E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY 4...

Page 1 of 152

Shutdown SIS

Previous Screen

Product: EXCAVATOR
Model: E70B EXCAVATOR 5TG
Configuration: E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY 4D32 ENGINE

Systems Operation
E70B EXCAVATOR HYDRAULIC SYSTEM
Media Number -SENR4815-01 Publication Date -03/01/1995 Date Updated -11/10/2001

Systems Operation

Introduction
Reference: For Systems Operation of the electronic controller, make reference to Systems
Operation E70B Excavators Electronic Controller, Form No. 4814.

Reference: For Testing And Adjusting of the hydraulic and electronics systems, make reference to
Testing And Adjusting For E70B Excavators Hydraulic And Electronic Systems, Form No.
SENR4816.

Reference: For illustrated Specifications, make reference to Form No. SENR4813, Specifications.

Hydraulic Schematic

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY 4...Page 2 of 152

(1) Stick Cylinder

This gives movements to the stick.

(2) Swing Motor

This is a fixed displacement, swash plate type motor that gives rotation to the upper structure.

(3) Travel Motor

This is a two-speed, variable displacement, swash plate type motor that gives rotations to the track.

(4) Boom cylinder

This gives movements to the boom.

(5) Bucket Cylinder

This gives movements to the bucket.

(6) Rotary Joint

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY 4...Page 3 of 152

This supplies the pressure oil from the rotating upper structure to the travel motors.

(7) Main Control Valves

These are controlled by the pilot valves and allow the pressure oil from the main pumps to flow to the travel or swing
motors and/or the implements.

(8) Main Relief Valve

This limits the oil pressure in the implements and swing circuits to 27500 kPa (4000 psi).

(9) Main Relief Valve

This limits the oil pressure in the travel circuit to 31400 kPa (4550 psi).

(10) Pilot Control Valve (Left Travel)

This is operated by left travel control lever or pedal and sends pilot oil to the main control valve for left travel.

(11) Pilot Control Valve (Right Travel)

This is the same as pilot control valve (10) in construction and operation. It sends pilot oil to the main control valve for
right travel.

(12) Pilot Control Valve (Stick and Swing)

This is operated by left control lever and sends pilot oil to the main control valves for stick and swing operations.

(13) Hydraulic Activation Control Valve

When the lever is in the locked position, no pilot oil is sent to the pilot control valves. So a machine cannot start
working. Engine can start only when the lever is in the locked position.

(14) Pilot Control Valve (Boom and Bucket)

This is the same as pilot control valve (12) in construction and operation. It sends pilot oil to the main control valves for
boom and bucket operations.

(15) Proportional Reducing Valve

The electronic controller feels the engine speed monitored by a sensor and develops an electronic signal. The reducing
valve receives this signal and develops a hydraulic signal which controls the pump output flow.

(16) Pilot Oil Manifold

This is a common source of pilot oil for the pilot relief valve, and proportional reducing valve.

(17) Slow Return Valve

This increases the oil pressure in the return line to make sure there is sufficient oil supply through the make-up line to
swing motor (2).

(18) Oil Cooler

This is connected to the engine radiator and cools the return oil from the main control valves.

(19) Shock Reducing Valve

This reduces the hydraulic shock transmitted from the implement to the machine when the stick stops retracting and the
boom stops retracting or extending.

(20) Hydraulic Tank

This is a container for the return oil from the main hydraulic system and from case drain of the motors.

(21) Bypass Check Valve

When the hydraulic oil temperature is not high enough, this allows the return oil to directly go back to tank (20) without
going through oil cooler (18).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY 4...Page 4 of 152

(22) Pilot Filter

This cleans the pilot system oil by removing the foreign particles.

(23) Pilot Line

This line is used for the load signal pressure to go from control valves (7) to the pumps.

(24) Rear Pump

This is directly connected to the front pump and sends the pressure oil to the inlet port located to the left of the main
control valves.

(25) Front Pump

This is directly coupled with the engine and sends the pressure oil to the inlet port located to the right of the main control
valves.

(26) Pilot Pump

This is a gear type pump which is directly connected to the rear pump and sends the pressure oil to the pilot system.

Pump Flow And Pressure Control

Introduction

Engine Compartment
(24) Rear pump. (25) Front pump. (26) Pilot pump.

This machine is driven and controlled by the main and pilot hydraulic systems.

The main hydraulic system provides oil to the cylinders and motors of the machine. The pilot
hydraulic system provides oil to the control circuits.

The main hydraulic system is driven by two variable displacement pumps (25) and (24) which make
up the main pumps. The pumps are identical in performance and operate using a common swash
plate. Front pump (25), directly connected to the engine by a flexible coupling is also coupled in
series with rear pump (24). Outside the main pumps, gear type pilot pump (26) drives the pilot
hydraulic system. These three pumps run at the same speed as the engine (1800 rpm.). All engine
output is used for driving these three pumps.

Each of the main pumps delivers 66.6 liters (17 U.S.gal) of hydraulic oil per minute at no load.
When a load is placed on the machine, the hydraulic oil is forced into the main hydraulic circuit,
overcoming the resistance. As a result, the delivery pressure of the main pumps increase. At the
same time, the engine speed decreases.

As the load increases, the main pumps increase their pressures until the relief pressures of 27500
kPa (4000 psi) for implements and swing and 31400 kPa (4550 psi) for travel. To maintain the

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY 4...Page 5 of 152

absorbed horsepower from the engine constant, the main pumps begin to decrease the flow rate as
the delivery pressure increases.

Main Control Valve Compartment

(27) Outlet line (front pump). (28) Valve block (travel control valve). (29) Outlet line (rear pump).

The oil delivered from front and rear pumps (25) and (24) enters travel control valve block (28) of
control valves (7). If no work is being performed, pump oil flows through the control valves and
returns tank (20). At the same time, the control valves send a low signal pressure to each pump
which causes the respective pump to destroke to minimum output flow.

If an operation is being performed, the control valves direct pump oil to the respective cylinders
(boom, bucket and stick) and / or motors (swing and travel). The control valves contain various
valve spools, passages, check valves and orifices which allow an operation to be done by itself or in
combination with other operations. The valve spools are controlled by pilot oil from the pilot oil
circuit.

Cab
(30) Control lever (stick and swing). (31) Control lever (boom and bucket).

Cab Floor
(32) Travel pedal (right). (33) Travel pedal (left).

Pilot pump (26) always delivers a constant flow of pressure oil and forces it into the pilot circuit.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY 4...Page 6 of 152

The pilot circuit has three major functions. One function is to operate the control valves. When any
control levers (30), (31) or pedals (32), (33) are operated, pilot oil flows to the main control valve
through pilot control valves (12), (14), (11) or (10) respectively. This operates the control valves.
The operating pilot pressure increases to the pilot relief valve setting, 3450 kPa (500 psi).

The pilot circuit also functions to control the oil flow of pump output. An electronic controller
develops an electronic signal by feeling the change in the engine speed. Reducing valve (15)
receives the electronic signal and uses the pilot system oil to develop the hydraulic signal pressure
(power shift pressure). The hydraulic signal pressure goes to the regulators in the main pumps and
controls the pump output flow.

A third function is to give pilot pressure to the three pressure switches (two of them optional)
located in the pilot circuit, so the following controls can be used.

1. Automatic Engine Speed Control (AEC)

The AEC system functions to automatically reduce the engine speed when no hydraulic
operation is called for.

When all control levers (30), (31) and pedals (32), (33) have been returned to the neutral
position, the pressure switch in the pilot circuit turns OFF because of a decrease in the pilot
pressure. After three seconds (if AEC switch is in the ON position) the AEC motor runs. This
overrides the governor control lever setting and reduces the engine speed to approximately
1100 rpm.

Any activation of control levers or pedals turns ON the pressure switch because of an increase
in the pilot pressure. This increases the engine speed to the governor control lever setting.

2. Swing Motor Parking Brake Release (If equipped)

Immediately after any control lever for implements or swing is operated, the pressure switch
for swing motor parking brake turns ON because of an increase in the pilot pressure. This
energizes solenoid valve (III) in pilot oil manifold (16) and a branch of the pilot circuit
directly releases the brake.

3. Travel Alarm Buzzer (If equipped)

When a travel pedal is depressed, the alarm buzzer circuit is placed in the ON state.

Following additional Solenoid Valves are provided in the pilot circuit. Each of these valves opens or
blocks a branch of the pilot line for activating a circuit selected for operation.

Solenoid I : for easier ground surface leveling by inching

Solenoid II : for easier vertical finishing of ditch wall surfaces

Main Pumps

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY 4...Page 7 of 152

Outside Views of Main Pumps

(1) Power shift pressure port. (2) Pilot oil port. (3) Port (load signal pressure). (4) Outlet port (front pump). (5) Front
pump. (6) Inlet port. (7) Rear pump. (8) Outlet port (rear pump).

The front and rear main pumps are identical in construction, operation and control.

Oil from the hydraulic oil tank enters inlet port (6) which is common to both the pumps. Each pump
delivers its oil through its respective outlet port (4) or (8).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY 4...Page 8 of 152

Cross Section Of Main Pump

(6) Inlet port. (9) Control piston. (10) Housing. (11) Swash plate. (12) Control piston. (13) Valve plate. (14) Shaft. (15)
Barrel. (16) Piston. (17) Guide. (18) Retainer. (19) Shoe. (20) Creep plate. (21) Shaft. (22) Bearing. (23) Inlet passage.
(24) Outlet passages.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY 4...Page 9 of 152

Cross Section Of Pump Regulator

(1) Port (power shift pressure). (9) Control piston. (10) Housing. (11) Swash plate. (12) Control piston. (25) Piston. (26)
Arm. (27) Spool. (28) Sleeve. (29) Spring. (30) Adjusting screw. (31) Check valve. (32) Piston. (33) Cover. (34) Spring.
(35) Spring. (36) Spool. (37) Pilot piston. (38) Check valve.

Shaft (14) is directly connected to the engine. Since barrel (15) and guide (17) are splined to shaft
(14), they all rotate together.

Barrel (15) has nine cylinders into which pistons (16) are inserted. Each piston is connected to shoe
(19). Retainer (18) holds shoes (19) against creep plate (20) on swash plate (11). As barrel (15)
turns, each piston (16) turns on plate (20) and follows the angle of swash plate (11). As the pistons
follow the angle of the swash plate, they move in and out of the cylinder in barrel (15). Each piston
draws the oil in during its downstroke on plate (20) and pushes the oil out during its upstroke.

The oil from the hydraulic tank enters inlet port (6). The oil then goes through inlet passage (23) in
valve plate (13) and is drawn in behind pistons (16) in barrel (15). The oil that is forced out by
pistons (16) goes to the main control valve lines through outlet passages (24) and outlet port (4) or
(8).

The pump regulator shown above controls the pump flow. The operating principle of the regulator
will be described in the next section.

Pump Regulation

Flow Control Under No Load

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 10 of 152

Hydralic Schematic Of Signal Pressure (Main Control Valves In Neutral)

(1) Main control valves. (2) Stick control valve. (3) Swing control valve. (4) Travel control valve (left). (5) Orifice. (6)
Travel control valve (right). (7) Attachment control valve. (8) Boom control valve. (9) Bucket control valve. (10) Pilot
passage. (11) Passage. (12) Pilot line. (13) Line. (14) Drain line. (15) Pilot oil manifold. (16) Piston chamber. (17)
Passage. (18) Pilot passage. (19) Passage. (20) Piston. (21) Control piston. (22) Rear pump. (23) Line. (24) Front pump.
(25) Pilot pump. (26) Suction line.

The oil pressure in line (13) between pilot pump (25) and orifice (5) is kept at 3450 kPa (500 psi).

The downstream part of pilot passage (10) from orifice (5) is connected to all of control valve
blocks. When no load is placed on the machine (all control valves in Neutral), there is an open
connection between pilot passage (10) and drain line (14). This holds the oil pressure in the pilot
passage low.

As any control levers are operated, passages of respective valves corresponding to passage (11) of
bucket control valve (9) are closed. This increases the pressure in pilot passage (10) to 3450 kPa
(500 psi). The increased pressure goes through pilot line (12) to pilot passage (18).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 11 of 152

Pump Regulator Operation (Under No Load)

(16) Piston chamber. (17) Passage. (18) Pilot passage. (19) Passage. (20) Piston. (21) Control piston. (22) Rear pump.
(24) Front pump. (27) Bushing. (28) Swash plate. (29) Spring chamber. (30) Spring. (31) Spool. (52) Check valve. (55)
Check valve. P1 : Delivery pressure (front pump). P2 : Delivery pressure (rear pump). PN : Load signal pressure. PP :
Pilot pressure.

When there is no load placed on the pumps, signal pressure PN in pilot passage (18) is held low. In
turn, spring (30) moves spool (31) all the way to the right. This opens a connection between
passages (19) and (17). The pilot pump oil PP can enter piston chamber (16).

Also, pump delivery pressure P1 or P2 which goes in spring chamber (29) is kept low when there is
no load on the pumps. This allows pilot pressure PP to move piston (20) to the right until it is in
direct contact with the left end of bushing (27). As piston (20) moves to the right, control piston (21)
also moves to the right which turns swash plate (28) in the direction for its smaller angle. As a
result, pump flow decreases to 34 liters/min. (9.0 U.S. gpm).

NOTE: Spool (31) and check valves (52) and (55) in above cross section have not been placed in
actual locations for illustrative purpose.

Horsepower Flow Control (Before Pump Destroke)

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 12 of 152

Pump Regulator Operation (Before Pump Destroke)

(16) Piston chamber. (17) Passage. (18) Pilot passage. (19) Passage. (20) Piston. (21) Control piston. (22) Rear pump.
(24) Front pump. (28) Swash plate. (29) Spring chamber. (30) Spring. (31) Spool. (32) Passage. (33) Passage. (34)
Piston. (35) Arm. (36) Spool. (37) Passage. (38) Spring. (39) Fulcrum point. (40) pilot piston. (41) Passage. (42) Control
piston. (43) Spring. (44) Piston chamber. (45) Piston chamber. (46) Piston chamber. (47) Passage. (48) Passage. (49)
Passage. (50) Passage. (51) Passage (to control valve). (52) Check valve. (53) Passage. (54) Passage (to control valve).
(55) Check valve. P1 : Delivery pressure (front pump). P2 : Delivery pressure (rear pump). PN : Load signal pressure.
PP : Pilot pressure. PS : Power shift pressure.

As any control valve is operated, a load is placed on the pumps. This develops a signal pressure PN
of 3450 kPa (500 psi) in pilot passage (10) in the control valves. The pressure goes to pilot passage
(18) to move spool (31) to the left against the force of spring (30). When this happens, there is no
pilot pump delivery pressure PP sent to passage (17) because passage (19) is closed.

At the same time, because passage (53) is open, the oil in piston chamber (16) is allowed to vent to
the tank through passages (17) and (53). As a result, the pressure in piston chamber (16) becomes
low.

The larger of front pump delivery pressure P1 or rear pump delivery pressure P2 goes in spring
chamber (29).

If pressure P1 is higher than pressure P2 (as shown above), check valve (55) is open and check valve
(52) is closed. This allows pressure P1 to go in spring chamber (29).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 13 of 152

If pressure P2 is higher than pressure P1, pressure P2 goes in spring chamber (29) because check
valve (52) is open and check valve (55) is kept closed.

The force of spring (43) plus the force of the pressure P1 or P2 pushes control piston (42), swash
plate (28) and control piston (21) all the way to the left.

Under this condition, front pump delivery pressure P1 goes through passage (49) and passage (48)
inside control piston (21), and enters piston chamber (45). At the same time, rear pump delivery
pressure P2 goes through passage (50) and passage (47) inside control piston (42), and enters piston
chamber (46). Pressures P1 and P2 in chambers (45) and (46) then act on pilot piston (40) to move it
up.

Because the areas of the pilot piston on which the pressures act are the same, the force that moves
the pilot piston up is proportional to the combined pressures of P1 and P2.

The force that moves pilot piston (40) up also acts on arm (35) to turn it clockwise with point (39) as
its fulcrum. At the same time, power shift pressure PS in passage (33) acting on piston (34) also
gives the force to turn arm (35) clockwise. As a result, these forces act on arm (35) to turn it
clockwise with point (39) as its fulcrum. This develops the force on regulator spool (36) against the
force of spring (38).

A smaller load on the pumps causes lower pump delivery pressure P1 and P2 and also higher engine
speed. This causes lower power shift pressure PS. Under this condition, total forces that try to turn
arm (35) clockwise are smaller than the force of spring (38) pushing to the left through spool (36).
Spool (36) can be held forced to the left to keep passage (37) closed. This blocks the flow of the
pump delivery oil in spring chamber (29) to piston chamber (44) through passages (41), (37) and
(32).

In turn, the pressure in piston chamber (44) is kept low and control piston (21) is held forced to the
left by the forces of spring (43) and control piston (42).

Now, the angle of swash plate (28) is kept maximum for maximum pump flow.

The maximum flow condition continues as long as the force of spring (38) turning arm (35) to the
left is larger than the combined forces of pump delivery pressure P1 and P2 and power shift pressure
PS that try to turn arm (35) to the right.

Horsepower Flow Control (After Start Of Pump Destroke)

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 14 of 152

Pump Regulator Operation (After Start Of Pump Destroke)

(21) Control piston. (28) Swash plate. (29) Spring chamber. (32) Passage. (34) Piston. (35) Arm. (36) Spool. (37)
Passage. (38) Spring. (39) Fulcrum point. (40) Pilot piston. (41) Passage. (42) Control piston. (43) Spring. (44) Piston
chamber. P1 : Delivery pressure (front pump). P2 : Delivery pressure (rear pump). PN : Load signal pressure. PS : Power
shift pressure.

An increase in load increases delivery pressures P1 and P2. It also decreases the engine speed which
results in increased power shift pressure PS. Eventually, the total forces which come from pilot
piston (40) and piston (34) to turn arm (35) clockwise overcome the force of spring (38). When this
happens, spool (36) moves to the right against the force of spring (38) to open passage (37). Now,
the pressure P1 or P2 in spring chamber (29) can go to piston chamber (44) through passages (41),
(37) and (32).

Because the area of control piston (21) on which the pressure acts is larger than that of control piston
(42), piston (21) turns swash plate (28) to the right for its smaller angle. This allows the pump to
start destroking.

Along with the movement of swash plate (28), pilot piston (40) also moves to the right. As piston
(40) comes closer to point (39) of arm (35), the forces turning arm (35) decreases. Eventually, the
forces are overcome by the force of spring (38) which in turn moves spool (36) to the left to close
passage (37) again.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 15 of 152

This blocks the supply of the pump oil through passage (32) to chamber (44) which in turn stops the
movement of swash plate (28).

When this happens, a balance condition builds up between forces caused by the pump delivery
pressure and power shift pressure to turn arm (35) clockwise and the force of spring (38). Thus,
swash plate (28) is held at a new angle according to the load at the time.

The delivery pressures from the front and rear pumps combine to move the swash plate, which is
common to both pumps. This in turn controls the pump flow. Even when the delivery pressure of
one pump is low with the other pump pressure high, the pump flow will be maintained. In this case,
when the two delivery pressure are combined, this combined delivery pressure is still low enough
not to affect pump output. This will be the case as long as the combined pressure is not high enough
for destroke to occur. The total output from both pumps under this condition is almost the same as
when both pumps are loaded.

Thus, after start of pump destroke, both pumps are always operated by the maximum horsepower
available from the engine, regardless of loads placed on respective pumps.

Pressure/Flow (P-Q) Characteristic Curves

P-Q Characteristic Curves

(1) Point (start of pump destroke). (2) Horsepower characteristics when power shift pressure is constant at 2570 kPa
(370 psi). (3) Point (end of pump destroke).

The output characteristics of each pump depends on two pressures:

1. Pump output circuit pressure.

2. Power shift pressure which varies as engine speed varies.

The main pumps on this machine use a common swashplate which is operated by the combined
output pressures from the front and rear pumps. For a given total pressure where pump 1 and pump
2 pressures are equal or different, the rate of flow from each pump will be equal at that particular
combined output pressure.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 16 of 152

A value for pump flow is determined only after both pump delivery pressure have been set at a given
value. The characteristic or pressure-flow (P-Q) curve during pump operation represents a set of
flow rates based on the following pressure conditions:

1. Pump 1 pressure is added to pump 2 pressure; and

2. Pump 1 pressure is equal to pump 2 pressure.

Point (1) represents the start of pump destroke, with the swashplate angle at maximum.

To correctly measure the pump flow during a field test, be sure to hold the output pressures of
both pumps equal.

Reference: For more information on the P-Q characteristic curves, make reference to the section
Pump Flow Tests, in Testing And Adjusting For E70B Excavators Electronic And Hydraulic
Systems, Form No. SENR4816.

Hydraulic Schematic Of Main Control Valves

(1) Boom control valve

(2) Line relief valve (stick cylinder head end)

(3) Line relief valve (stick cylinder rod end)

(4) Stick control valve

(5) Load check valve (stick cylinder)

(6) Return passage

(7) Swing control valve

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 17 of 152

(8) Load check valve (swing motor)

(9) Parallel feeder passage

(10) Left travel control valve

(11) Center bypass passage

(12) Straight travel valve

(13) Return line

(14) Return port

(15) Main control valves

(16) Right travel control valve

(17) Center bypass passage

(18) Attachment control valve

(19) Load check valve (boom cylinder)

(20) Boom control valve

(21) Line relief valve (boom cylinder head end)

(22) Line relief valve (boom cylinder rod end)

(23) Load check valve

(24) Bucket control valve

(25) Line relief valve (bucket cylinder head end)

(26) Stick control valve

(27) Main relief valve (implements/swing)

(28) Main relief valve (travel)

(29) Logic valve

(30) Inlet port (front pump)

(31) Inlet port (rear pump)

(32) Return passage

(33) Parallel feeder passage

(34) Selector valve

(35) Outlet line (front pump)

(36) Outlet line (rear pump)

(37) Hydraulic tank

(38) Rear pump

(39) Pilot pump

(40) Front pump

Main Control Valves

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 18 of 152

Introduction
Main control valves (15) are located in the hydraulic system between the pumps and actuators
(cylinders and motors). The control valves control the flow and the pressure in the circuits from the
pumps to actuators. Depending on the machine operation, components and passages in the control
valves function to control flow and pressure.

In this section, a general circuit and component description is given for the following control valve
operations:

1. Main Control Valves In Neutral

2. Individual Control Valve
3. Pilot Control
4. Combined Implements/Motors. (Including pump flow combined operation of boom and
stick.)

Detailed information on the above items 1 and 2 is given in this Control Valve section. For detailed
information on items 3 and 4, see separate "OPERATION" sections involved.

Circuit Flow Illustration (Main Control Valves In Neutral)

(1) Boom control valve. (4) Stick control valve. (6) Return passage. (7) Swing control valve. (10) Left travel control
valve. (11) Center bypass passage. (12) Straight travel valve. (13) Return line. (15) Main control valves. (16) Right
travel control valve. (17) Center bypass passage. (18) Attachment control valve. (20) Boom control valve. (24) Bucket
control valve. (26) Stick control valve. (32) Return passage. (38) Rear pump. (39) Pilot pump. (40) Front pump.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 19 of 152

Circuit Flow Illustration (Individual Control Valve Operation) (Stick And Bucket Cylinder Operations As A Typical
Example)
(2) Line relief valve (stick cylinder head end). (3) Line relief valve (stick cylinder rod end). (4) Stick control valve. (5)
Load check valve. (11) Center bypass passage. (15) Main control valves. (17) Center bypass passage. (23) Load check
valve. (24) Bucket control valve. (25) Line relief valve (bucket head end). (27) Main relief valve (implements/swing).
(28) Main relief valve (travel). (33) Parallel feeder passage. (34) Selector valve. (38) Rear pump. (40) Front pump. (54)
Passage. (55) Check valve.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 20 of 152

Circuit Flow Illustration (Pilot Control Operation)

(12) Straight travel valve. (15) Main control valves. (24) Bucket control valve. (39) Pilot pump. (41) Pressure switch
(swing parking brake). (42) Pressure switch (AEC). (43) Pilot passage. (44) Pilot passage. (45) Pilot passage. (46) Pilot
passage. (47) Drain passage. (48) Pilot control valve for boom and bucket cylinders. (49) Drain line.

Circuit Flow Illustration (Combined Operation And Pump Flow Combined Operation)
(1) Boom control valve. (4) Stick control valve. (11) Center bypass passage. (12) Straight travel valve. (15) Main control
valves. (17) Center bypass passage. (26) Stick control valve. (29) Logic valve. (34) Selector valve. (50) Check valve.
(51) Check valve. (52) Passage. (53) Passage.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 21 of 152

Control Valve Blocks

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 22 of 152

Main Control Valves (Outside Views)

(1) Boom. (2) Stick. (3) Swing. (4) Left travel. (5) Straight travel. (6) Travel control valve block. (7) Right travel. (8)
Attachment. (9) Boom. (10) Bucket. (11) Stick. (12) Return port. (13) Main relief valve (travel). (14) Main relief valve
(implements/swing). (15) Inlet port (rear pump). (16) Inlet port (front pump).

Main Control Valves (Viewed From Top Of Machine)

(1) Boom. (2) Stick. (3) Swing. (4) Left travel. (5) Straight travel. (6) Travel control valve block. (7) Right travel. (8)

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 23 of 152

Attachment. (9) Boom. (10) Bucket. (11) Stick. (13) Main relief valve (travel). (14) Main relief valve
(implements/swing). (17) Return line. (18) Outlet line (rear pump). (19) Outlet line (front pump).

Travel control valve block (6) which contains left travel control valve (4), right travel control valve
(7) and straight travel valve (5) is located at the center of the main control valve blocks. Swing
control valve (3), stick control valve (2) and boom control valve (1) which are in parallel
arrangement are bolted to the left side of block (6). To its right side, attachment control valve (8),
boom control valve (9), bucket control valve (10) and stick control valve (11) are also bolted in
parallel arrangement.

Travel control valve block (6) has inlet ports (15) and (16) and return port (12). Inlet port (16)
allows the front pump oil to enter the control valve from outlet line (19). Inlet port (15) allows the
rear pump oil to enter the control valve from outlet line (18). Return oil from the control valve goes
out through return port (12) and back to the hydraulic tank through return line (17).

Main relief valves (13) and (14) are located on the top of block (6). Relief valve (13) limits the
maximum pump pressure in the travel circuit to 31400 kPa (4550 psi). Relief valve (14) limits the
maximum pump pressure in the implement and swing circuits to 27500 kPa (4000 psi).

Cross Section Of Control Valve

(1) Boom control valve. (2) Stick control valve. (3) Swing control valve. (4) Left travel control valve. (5) Straight travel
valve. (7) Right travel control valve. (8) Attachment control valve. (9) Boom control valve. (10) Bucket control valve.
(11) Stick control valve. (12) Return port. (15) Inlet port (rear pump). (16) Inlet port (front pump). (20) Center bypass
passage. (22) Center bypass passage. (23) Return passage. (24) Parallel feeder passage. (25) Parallel feeder passage. (26)
Return passage.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 24 of 152

The right control valve blocks are supplied front pump oil from inlet port (16) through center bypass
passage (22) and parallel feeder passage (25). The left control valve blocks are supplied rear pump
oil from inlet port (15) through center bypass passage (20) and parallel feeder passage (24).

When all of control levers are in the NEUTRAL position (no load placed on the machine), front
pump oil flows through center bypass passage (22) and return passage (26) and out through return
port (12). The oil then flows back to the hydraulic tank through return line (17).

Rear pump oil flows through center bypass passage (20) and return passage (23) and combines with
front pump oil at return port (12). The combined oil then goes back to the tank. Oil in parallel feeder
passages (24) and (25) supplied from both pumps remains blocked.

Activation of any control levers provides two paths for front pump oil. One path is from center
bypass passage (22) to right travel control valve (7). The other path is from parallel feeder passage
(25) to valves for attachment (8), boom (9) and bucket (10). At the same time, it provides two paths
for rear pump oil. One path is from center bypass passage (20) to valves for left travel (4) and stick
(2). The other path is from parallel feeder passage (24) to swing control valve (3).

Individual Valve Operation

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 25 of 152

Cross Section Of Bucket Control Valve (NEUTRAL Position)

(1) Bucket control valve. (2) Spring. (3) Cylinder port. (4) Cylinder port. (5) Pilot port. (6) Pilot port. (7) Passage. (8)
Center bypass passage. (9) Load check valve. (10) Parallel feeder passage. (11) Return passage. (12) Spool.

The bucket control valve is used as a typical example for describing the operation of individual
control valves.

When all controls are in Neutral, there is no pilot oil sent to pilot ports (5) and (6) from the pilot
control valve. In turn, spool (12) is centered in the neutral position by the force of spring (2). Front
pump oil goes through center bypass passage (8) to the hydraulic tank.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 26 of 152

Cross Section Of Bucket Control Valve (Bucket CLOSE Position)

(3) Cylinder port. (4) Cylinder port. (6) Pilot port. (7) Passage. (8) Center bypass passage. (9) Load check valve. (10)
Parallel feeder passage. (11) Return passage. (12) Spool. (13) Passage. (14) Orifice. (15) Passage. (16) Passage.

When the bucket control valve is operated to the bucket CLOSE position, pilot oil is supplied to
pilot port (6) which moves spool (12) to the left. This closes center bypass passage (8) and opens
passage (16). At the same time, passages (13) and (15) and orifice (14) are connected to return
passage (11).

Front pump oil in parallel feeder passage (10) flows through load check valve (9), passages (7) and
(16) to cylinder port (3). This extends the bucket cylinder which in turn allows the oil in the rod end
to flow to cylinder port (4).

Oil from cylinder port (4) flows through passages (13) and (15). The oil then goes through orifice
(14) to return line (11) and back to the hydraulic tank. Orifice (14) works like a slow return valve in
bucket CLOSE operation.

Load Check Valve

Combined Operations

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 27 of 152

Cross Section Of Boom Control Valve (Boom RAISE Position)

(1) Bucket control valve. (2) Load check valve. (3) Boom control valve. (4) Passage. (5) Cylinder port. (6) Cylinder
port. (7) Pilot port. (8) Return passage. (9) Load check valve. (10) Parallel feeder passage. (11) Boom cylinder. (12)
Passage. (13) Spool. W : Load.

Each of the control valves has a load check valve. During a combined operation of cylinders and/or
motors, if the oil pressure in one control valve is less (or becomes less) than the oil pressure in the
other control valve, the load check valve will close to prevent reverse oil flow.

As a typical example, when boom cylinder (11) is extended, there is pilot oil supplied to port (7)
which moves spool (13) to the left. Pump oil from parallel feeder passage (10) flows through load
check valve (9) to passage (4). The oil then flows through passage (12) to cylinder port (5). This
raises the boom.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 28 of 152

Cross Section Of Boom Control Valve (Load Check Valve Closed)

(4) Passage. (5) Cylinder port. (9) Load check valve. (10) Parallel feeder passage. (11) Boom cylinder. (12) Passage. W :
Load.

However, during a combined operation of boom RAISE and bucket, the load on the boom cylinder
is larger than that on the bucket cylinder.

Boom control valve (3) and bucket control valve (1) are supplied oil through the common parallel
feeder passage (10).

Because of the smaller load during bucket cylinder operation, the pressure in parallel feeder passage
(10) is lower than the pressure used for boom RAISE. As a result, the boom will start to lower
because of load W. The oil available for boom RAISE will start to flow back through cylinder port
(5) and passage (12) to passage (4). However, the pressure in passage (4) is higher than the pressure
in parallel feeder passage (10). As a result, load check valve (9) closes and prevents reverse oil flow.
The boom does not lower.

Load check valves used in other control valves work in the same way as that described above.

Inching Operations

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 29 of 152

Cross Section Of Stick Control Valve (Inching Operation For Stick OUT)
(1) Cylinder port. (2) Passage. (3) Load check valve. (4) Passage. (5) Passage. (6) Pilot port. (7) Spool. (8) Passage. (9)
Center bypass passage.

Also, the load check valve functions to prevent reverse oil flow during an inching operation.

As a typical example, an inching movement of the control valve for stick OUT results in pilot oil to
port (6). This in turn moves spool (7) to the right a small distance. Because passage (5) is partially
open, part of the oil from center bypass passage (9) returns to tank. Remainder of the oil from center
bypass passage (9) flows to passage (4). The oil then goes through load check valve (3), passages (2)
and (8) to cylinder port (1). This slowly retracts the stick cylinder for inching operation of stick
OUT.

Center bypass passage (9) does not provide enough pressure because part of oil goes to tank. If the
load on the stick is larger than the pressure available for stick OUT, the stick will start to move IN.
(The stick cylinder rod will start to extend.) The oil available for stick OUT will start to return
through port (1) to center bypass passage (9) through passages (8) and (2). When this condition
happens, the pressure in port (1) is higher than the pressure in bypass passage (9). As a result, load
check valve (3) closes to prevent this reverse oil flow.

Line Relief And Make-up Valves

Main Control Valves (Viewed From Top Of Machine)

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 30 of 152

(1) Line relief valve (bucket cylinder head end). (2) Line relief valve (boom cylinder head end). (3) Line relief valve
(stick cylinder head end)

In the line between each cylinder and its control valve are line relief and make up valves. When an
outside force operates against a cylinder whose control valve is in Neutral, the pressure in the
cylinder and the circuit to the control valve increases. During the pressure increase, the line relief
valve limits the pressure to 30900 kPa (4500 psi) [or 23000 kPa (3350 psi) on boom cylinder rod
end]. The line relief valve also operates as make-up valve.

If an outside force acts on the cylinder rod of a control valve that is in Neutral, the cylinder piston
will try to move. A vacuum will occur in the cylinder. Immediately after this happens, the make-up
part of the valve sends part of the return oil to the cylinder. This removes the vacuum condition
immediately after it has occurred in the cylinder.

Line Relief Valve Operation

Cross Section Of Line Relief Valve (Valve CLOSED Position)

(4) Orifice. (5) Poppet. (6) Poppet. (7) Pilot poppet. (8) Spring. (9) Cylinder passage. (10) Spring chamber.

The high pressure oil from cylinder passage (9) goes through orifice (4) in poppet (5) to spring
chamber (10). The pressures working against spring chamber (10) side and the cylinder passage (9)
side of poppets (5) and (6) are the same.

Because there is more surface area on the spring chamber side of the poppets than on the cylinder
passage side, both poppets are pushed all the way to the left and the valve is fully closed.

As long as the force of spring (8) is greater than the oil pressure in chamber (10), pilot poppet (7) is
kept closed. This allows no oil flow from chamber (10).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 31 of 152

Cross Section Of Line Relief Valve (Pilot Poppet OPEN Position)

(6) Poppet. (7) Pilot poppet. (8) Spring. (10) Spring chamber. (11) Return passage. (12) Passage.

The pressure of the oil in spring chamber (10) is working against pilot poppet (7). As the force of oil
pressure in chamber (10) becomes larger than the force of spring (8), pilot poppet (7) opens. This
allows the oil to flow through passage (12) and go around poppet (6) to return passage (11).

Cross Section Of Line Relief Valve (Valve OPEN Position)

(5) Poppet. (9) Cylinder passage. (10) Spring chamber. (11) Return passage. (13) Adjusting screw.

As a result, the pressure in spring chamber (10) decreases. Then oil pressure from cylinder passage
(9) moves poppet (5) to the right and flows directly to return passage (11). The circuit pressure is
limited to each relief pressure setting. The pressure adjustment can be made by adjusting screw (13).

Make-Up Valve Operation

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 32 of 152

Cross Section Of Line Relief Valve (Make-up Valve In Operation)

(4) Orifice. (5) Poppet. (6) Poppet. (9) Cylinder passage. (10) Spring chamber. (11) Return passage. (14) Shoulder.

When oil is lost through operation of the line relief for the rod (haed) end of a cylinder, then oil has
to be made up (replaced) in the head (rod) end respectively to prevent a vacuum condition.

Because passage (9) is connected to chamber (10) through orifice (4), a vacuum can occur in
passage (9) and chamber (10) at the same time.

Shoulder (14) of poppet (6) receives the oil pressure from return passage (11) and its back side
receives the negative pressure occurred in chamber (10). As a result, poppet (6) moves to the right.
Now the oil from return passage (11) goes to passage (9) as make-up oil. This removes the vacuum
immediately after it has occurred in passage (9).

Main Relief Valve

Hydraulic Schematic (Partial) (Main Relief Valves And Pilot Oil Circuit)
(1) Return port. (2) Swing control valve. (3) Main relief valve (implements/swing). (4) Right travel control valve. (5)
Main relief valve (travel). (6) Pilot passage. (7) Orifice. (8) Main poppet. (9) Passage. (10) Pilot passage. (11) Pilot

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 33 of 152

passage. (12) Spool. (13) Passage. (14) Passage. (15) Passage. (16) Check valve. (17) Check valve. (18) Passage. (19)
Front pump. (20) Rear pump. (21) Pilot pump.

Cross Section Of Main Relief Valve (Valve CLOSED Position)

(3) Main relief valve (implements and swing). (5) Main relief valve (travel). (6) Pilot passage. (11) Pilot passage. (13)
Passage. (15) Passage. (16) Check valve. (17) Check valve. (18) Passage. (19) Front pump. (20) Rear pump.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 34 of 152

Main Control Valve (Viewed From Top Of Machine)

(3) Main relief valve (implements/swing). (5) Main relief valve (travel).

There are two types of main relief valves located on the top of the main control valves. One is for
the travel circuit. The other is for the implements and swing circuits.

Oil from front pump (19) flows through passage (15) and check valve (16) to passage (13). Rear
pump (20) oil flows through passage (18) and check valve (17) to passage (13).

Activation of the travel control lever/pedal closes passage (14) of right travel control valve (4). This
increases the pressure in pilot passage (6) to 3450 kPa (500 psi) which is the relief pressure setting
of the pilot circuit.

Activation of the swing or an implement control lever closes the pilot oil passage of its valve. [This
passage location is similar to that of passage (9) relative to swing control valve (2).] As a result, the
pressure in both pilot passages (10) and (11) is equal to the relief pressure setting of the pilot circuit.

Main Relief Valve Operation (Travel Circuit)

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 35 of 152

Cross Section Of Main Relief Valve (Valve In Operation, With Main Poppet CLOSED)
(1) Return port. (5) Main relief valve (travel). (6) Pilot passage. (7) Orifice. (8) Main poppet. (12) Spool. (13) Passage.
(22) Passage. (23) Spring. (24) Poppet. (25) Passage. (26) Spring. (27) Passage. (28) Passage.

Activation of the travel control lever/pedal makes the pressure in pilot passage (6) equal to the pilot
relief pressure setting. This moves spool (12) to the right against the force of spring (26). This in
turn closes passage (22) to relief valve (3) and allows pump pressure only through passage (28) to
relief valve (5).

Front or rear pump oil coming through passage (13) flows through orifice (7) in main poppet (8),
passage (25) and then acts on poppet (24). As the oil pressure overcomes the relief setting force of
spring (23), poppet (24) opens. In turn, oil goes through passage (27) and out through return port (1)
to the tank.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 36 of 152

Cross Section Of Main Relief Valve (Valve In Operation, With Main Poppet OPEN)
(1) Return port. (7) Orifice. (8) Main poppet. (13) Passage. (24) Poppet. (29) Spring chamber. (30) Spring.

Because there is flow through orifice (7) and poppet (24) to tank, the pressure in chamber (29)
decreases. This allows main poppet (8) to move and compress spring (30). This allows front or rear
pump oil from passage (13) to return to tank through return port (1).

Main Relief Valve Operation (Implement/Swing Circuits)

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 37 of 152

Cross Section Of Main Relief Valve (Valve In Operation)

(1) Return port. (3) Main relief valve (implements/swing). (5) Main relief valve (travel). (6) Pilot passage. (7) Orifice.
(8) Main poppet. (11) Pilot passage. (12) Spool. (13) Passage. (23) Spring. (24) Poppet. (25) Passage. (26) Spring. (27)
Passage. (28) Passage. (31) Spring. (32) Poppet. (33) Passage. (34) Passage. (35) Passage.

Activation of an implement or swing control lever makes the pressure in pilot passages (6) and (11)
equal. Because the same amount of pressure is acting on each end of spool (12), spool (12) is moved
to the left by the force of spring (26). This opens passage (34).

Front or rear pump oil coming through passage (13) flows through orifice (7) in main poppet (8) to
passage (35). The oil then flows in two paths. One path is through passage (34) to poppet (32) and
the other is through passage (25) to poppet (24).

Because the force of spring (23) is higher than that of spring (31), poppet (24) remains closed.

As the oil pressure overcomes the relief setting force of spring (31), poppet (32) is opened. This
allows the oil to flow through passage (27) and out through return port (1) to the tank.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 38 of 152

In the same manner as for main relief valve operation in the travel circuit, main poppet (8) is
opened. In turn, all of pump oil flows to the tank.

Hydraulic Schematic For Pilot Oil

(1) Swing parking brake

(2) Pressure switch (swing parking brake release)

(3) Pressure switch (AEC)

(4) Main control valves

(5) Pilot line (stick)

(6) Pilot line (swing)

(7) Pilot line (left travel)

(8) Straight travel valve

(9) Pilot passage (straight travel valve)

(10) Pilot passage (pressure switch for swing parking brake release)

(11) Pilot passage (pressure switch for AEC)

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 39 of 152

(12) Pilot line (right travel)

(13) Pilot line (boom)

(14) Pilot line (bucket)

(15) Pilot line (stick combiner)

(16) Orifice (swing parking brake release pilot operation)

(17) Orifice (AEC pilot operation)

(18) Pilot control valve (left travel)

(19) Pilot control valve (right travel)

(20) Pilot line (boom combiner)

(21) Pilot line (stick)

(22) Pilot line (swing)

(23) Pilot line (left travel)

(24) Pilot line (right travel)

(25) Pilot line (boom)

(26) Pilot line (bucket)

(27) Pilot oil supply line

(28) Pilot control valve (swing and stick)

(29) Pilot oil supply line

(30) Hydraulic activation control valve

(31) Pilot oil supply line

(32) Pilot control valve (boom and bucket)

(33) Drain line

(34) Pilot oil supply line

(35) Proportional reducing valve

(36) Pilot oil supply line

(37) Passage

(38) Pilot oil manifold

(39) Passage

(40) Pilot line (power shift pressure)

(41) Pilot filter

(42) Outlet line (pilot pump)

(43) Pilot pump

(55) Solenoid valve III (swing parking brake release)

Pilot Oil Supply

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 40 of 152

Introduction

Pump Compartment
(35) Proportional reducing valve. (38) Pilot oil manifold. (41) Pilot filter. (42) Outlet line. (43) Pilot pump.

The pilot system oil output from pilot pump (43) goes through outlet line (42) and pilot filter (41)
and enters pilot oil manifold (38). The oil then goes to the following circuits:

1. Pilot control valve

2. Proportional reducing valve
3. Pilot circuits in main control valves following:

a) Pressure switch circuit for AEC

b) Pressure switch circuit for swing parking brake release
c) Straight travel valve circuit

Pilot Control Valve Circuits

Cab
(18) Pilot control valve (left travel). (19) Pilot control valve (right travel). (28) Pilot control valve (swing and stick). (32)
Pilot control valve (boom and bucket).

When any of pilot control valves (18), (19), (28) and (32) are operated, pilot oil goes to a main
control valve. The pilot oil shifts the spool in the control valve to operate a cylinder and/or motor.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 41 of 152

Viewed From Under Cab Floor

(30) Hydraulic activation control valve.

Hydraulic Activation Control Lever (LOCK Position)

(44) Lever.

Hydraulic Activation Control Lever (UNLOCK Position)

(44) Lever.

Hydraulic activation control valve (30) is part of the pilot control valve circuit. When hydraulic
activation control lever (44) is placed in the LOCK position, valve (30) is closed to block the pilot
oil supply to any of pilot control valves. None of the main control valve spools can be moved.

NOTE: Valve (30) cannot control the functions of the blade cylinder of the blade machine.

Valve (30) is equipped with a limit switch which allows the starting switch to operate only when
lever (44) is in the LOCK position.

Pilot pump oil which enters pilot oil manifold (38) flows through passage (39). Part of pilot oil from
passage (39) flows to hydraulic activation control valve (30). When lever (44) is in the UNLOCK
position, pilot oil in line (36) goes in pilot control valves (18), (19), (28) and (32) through respective
lines (27), (29) and (31). Under this condition, there is no flow between line (36) and drain line (33).

When lever (44) is in the LOCK position, valve (30) closes line (36) to block the pilot oil supply to
any of pilot control valves. When this happens, the oil in lines (27), (29) and (31) passes through
valve (30) to drain line (33). The oil then flows through pilot oil manifold (38) to the pump suction
line.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 42 of 152

Main Control Valve Compartment (Top View) (Pilot Oil Lines)

(20) Boom combiner. (21) Stick. (22) Swing. (23) Left travel. (24) Right trave. (25) Boom. (26) Bucket.

Main Control Valve Compartment (Bottom View) (Pilot Oil Lines)

(5) Stick. (6) Swing. (12) Right travel. (13) Boom. (14) Bucket.

Pilot oil from pilot control valves goes through respective pilot lines to ports of control valve(s)
selected for operation(s). This shifts spools of main control valves to operate cylinders and/or
motors.

Proportional Reducing Valve Circuit

Pump Compartment
(35) Proportional reducing valve. (38) Pilot oil manifold. (40) Pilot line.

Part of the pilot pump oil in passage (39) goes through line (37) to proportional reducing valve (35).
Valve (35) continuously receives an electrical signal from the electronic controller based on the
engine speed. Valve (35) then changes the pilot oil sent from passage (37) into a hydraulic signal
(power shift pressure). The hydraulic signal goes through pilot line (40) to the regulator of the main
pump which in turn controls the pump output flow.

Pilot Oil Circuits In Main Control Valves

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 43 of 152

Hydraulic Schematic (Partial)

(2) Pressure switch (swing parking brake release). (3) Pressure switch (AEC). (4) Main control valves. (8) Straight travel
valve. (9) Pilot passage. (10) Pilot passage. (11) Pilot passage. (16) Orifice. (17) Orifice. (34) Line. (38) Pilot oil
manifold. (39) Passage. (43) Pilot pump. (45) Swing control valve. (46) Passage. (47) Travel control valve (left). (48)
Passage. (49) Travel control valve (right). (50) Passage. (51) Passage. (52) Passage. (53) Port. (54) Drain line. (55)
Solenoid valve III.

Cross Section Of Travel Control Valve (Left)

(2) Pressure switch (swing parking brake release). (3) Pressure switch (AEC). (10) Pilot passage. (11) Pilot passage. (16)
Orifice. (17) Orifice. (34) Line. (45) Swing control valve. (46) Passage. (47) Travel control valve (left). (48) Passage.
(49) Travel control valve (right). (51) Passage. (52) Passage. (53) Port. (54) Drain line.

Main Control Valve Compartment (Top View)

(2) Pressure switch (swing parking brake release). (3) Pressure switch (AEC). (34) Line (pilot oil).

Part of pilot oil in passage (39) of pilot oil manifold (38) goes to valves (4) through line (34).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 44 of 152

The pressure in the pilot oil circuit between pilot pump (43) and orifice (16) or (17) is kept at the
pilot relief pressure setting of 3450 kPa (500 psi). This pilot pressure oil is supplied to the following
circuits:

1. Pressure switch circuit for AEC

2. Pressure switch circuit for swing parking brake release
3. Straight travel valve circuit

Pressure Switch Circuit (AEC)

Important passages in this circuit are pilot passages (11), (48) and (51). When the machine is
operated with no-load, the pressure in this circuit is kept low. Pressure switch (3) is in the OFF
position which in turn allows the Automatic Engine Speed Control (AEC) of the electronic
controller system to operate for a decrease in engine speed.

When a load is placed on the machine, the pressure in this circuit increases to the pilot relief setting.
This turns ON switch (3) to operate AEC system for an increase in engine speed (to the governor
lever setting).

In addition, when AEC pressure switch (3) is in the OFF position (no-load placed on the machine),
the electronic controller feels the no-load engine speed. Just before the engine speed is decreased by
the controller, it determines the target speed.

As an operation is started again, the controller allows the proportional reducing valve to control the
pump output depending on engine speed at the time.

When all control levers are in the NEUTRAL position, all of oil flow in passage (48) beyond orifice
(17) enters right travel control valve (49) and then goes through all of remaining control valves to
drain line (54).

The circuit pressure in passage (48) is low which maintains pressure switch (3) in the OFF position.
As a result, the AEC motor operates to decreases the engine speed.

When a control valve(s) is operated, the operating control valve blocks oil flow through passage
(48). This increases the circuit pressure in passage (48) and pilot passage (11) to the pilot relief
setting. In turn, switch (3) turns ON to operate the AEC motor for an increase in engine speed to the
governor lever setting.

Reference: For more details, reference the module, E70B Excavator, Systems Operation Electronic
System, Form No. SENR4814.

Pressure Switch Circuit (Swing Parking Brake Release)

Important passages in this circuit are pilot passages (10) and (52).

When the circuit pressure in pilot passages (10) and (52) increase to the pilot relief setting, pressure
switch (2) turns ON. This activates solenoid valve III (55) located on pilot oil manifold (38).
Solenoid valve III (55) allows pilot oil to pass to swing parking brake (1). In turn, brake (1) releases
to allow the swing motor to turn.

Oil flow in passage (52) beyond orifice (16) combines at passage (46) with oil flow from passage
(51). The combined oil passes through swing control valve (45) and remaining control valves except
for travel and goes to drain line (54).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 45 of 152

When any of the implement and swing control valves is operated, the operating valve blocks oil
flow beyond itself in passage (46). This increases the pressure in passage (52) and pilot passage (10)
to the pilot relief setting. As a result, pressure switch (2) turns ON to operate solenoid valve III (55).
Pilot oil can then go to swing parking brake (1) to release the brake.

For more details, see the section, Swing Control.

Straight Travel Valve Circuit

The major passage in this circuit is pilot passage (9). When the pressure in this circuit increases to
the pilot relief setting, straight travel valve (8) operates. No combined operations of travel and any
of implements and/or swing would affect the straight travel of the machine.

When travel control valves (47) and (49) are operated, pilot oil in pilot passage (9) goes through
both valves (47) and (49). When any of implements and/or swing is operated simultaneously, the
operating valve blocks the oil flow in passage (50) beyond the valve. This increases the circuit
pressure in passage (50) to the pilot relief setting which in turn operates straight travel valve (8).

For more details, see the section, Straight Travel Control.

Pilot Pump

Pump Compartment
(1) Pilot pump. (2) Pilot filter.

Pilot pump (1) is a gear type pump mounted on the main pumps. It supplies pressure oil to the pilot
system. At full load rpm, its output flow is 16 liter/min. (4.2 U.S. gpm).

Pilot Filter

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 46 of 152

Cross Section Of Pilot Filter

(2) Pilot filter. (3) Relief valve. (4) Filter element.

Filter element (4) in pilot filter (2) removes contaminants from the pilot oil.

If the oil flow through filter element (4) becomes restricted due to too cold oil or too much
contaminants, the oil bypasses the filter through relief valve (3) which is part of pilot filter (2).

Manifold Components (Mounted ON)

Pump Compartment
(1) Line (to main control valves). (2) Solenoid valve I. (3) Solenoid valve II. (4) Solenoid valve III. (5) Proportional
reducing valve. (6) Line (from pilot filter). (7) Accumulator. (8) Line (to hydraulic activation control valve). (9) Pilot oil
manifold. (10) Pilot relief valve.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 47 of 152

Cross Section Of Pilot Oil Manifold

(1) Line (to main control valves). (5) Proportional reducing valve. (6) Line (from pilot filter). (7) Accumulator. (8) Line
(to hydraulic activation control valve). (9) Pilot oil manifold. (10) Pilot relief valve. (11) Passage. (12) Check valve. (13)
Passage. (14) Passage.

Pilot oil coming through the pilot filter and line (6) enters pilot oil manifold (9) and goes through
passage (14). The oil then flows in three directions as follows:

1. To the hydraulic activation control valve through check valve (12), passage (13) and line
(8).
2. To proportional reducing valve (5) through passage (11).
3. To the main control valves through line (1).

Pilot oil in passage (13) is also at the inlets of pilot relief valve (10) and accumulator (7).

Pilot Relief Valve

Pilot relief valve (10) limits the pressure in the pilot circuit to 3450 kPa (500 psi). Since the flow of
oil in the pilot system is a small amount, most of output from the pilot pump goes through the pilot
relief valve.

Most of the oil needed by the pilot system is used to shift one or more of the spools in the main
control valves.

The pilot relief valve keeps the pilot pressure at 3450 kPa (500 psi) except for short periods when a
main control valve spool is operated.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 48 of 152

Accumulator

Cross Section Of Accumulator

(15) Gas chamber. (16) Bladder. (17) Bowl. (18) Oil Chamber. (19) Inlet port.

Accumulator (7) provides oil to the pilot line as makeup oil. During combined operations, the pilot
system needs more oil because there is not enough pilot pump oil. Also, when lowering implements
immediately after the engine has been stopped, makeup oil supply is needed.

The accumulator stores hydraulic pressure by taking advantage of the compressibility of nitrogen
gas put in gas chamber (15).

The pilot pump oil goes through inlet port (19) and in oil chamber (18). The oil remains there and
works against the gas in chamber (15) through bladder (16).

Check valve (12) which is located in the passage connected to inlet port (19) prevents pressure oil
from the accumulator from flowing back to line (6).

Accumulator oil can work like pilot pressure for a short period (less than a minute) after the engine
has been stopped. For example, accumulator oil can be used to lower the implements to the ground.

Solenoid Operated Valves

There are three solenoid valves mounted on pilot oil manifold (9).

When the solenoid of a valve receives an electrical signal, it energizes and operates the valve part.

For description of operation of each valve, see the section given separately.

Solenoid valve I (2); provides easier inching operation for leveling. For more information, see the
section, Leveling Operation.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 49 of 152

Solenoid valve II (3); provides easier ditch excavation operation. For more information, see the
section, Ditch Excavation Operation.

Solenoid valve III (4) (If equipped); releases the swing parking brake. For more information, see the
section, Swing Control.

Hydraulic Activation Control Valve

Cross Section Of Hydraulic Activation Control Valve (UNLOCK Position)

(1) Hydraulic activation control valve. (2) Port (pilot control valve for right and left travel). (3) Port (pilot control valve
for boom and bucket). (4) Port (pilot control valve for swing and stick). (5) Spool. (6) Return port (pilot control valve for
swing and stick). (7) Return port (pilot control valve for right and left travel). (8) Return port (pilot control valve for
boom and bucket). (9) Inlet port (pilot oil). (10) Hydraulic activation control lever.

When hydraulic activation control lever (10) is placed in the LOCK position, port (9) is closed and
there is no pilot oil supplied to hydraulic activation control valve (1). At the same time, ports (2), (3)
and (4) are connected to the pump suction line through port (7).

This blocks pilot oil flow to any of pilot control valves and none of main control valve spools can be
moved.

When lever (10) is in the UNLOCK position, port (9) opens and ports (6), (7) and (8) are closed. In
this position, the pilot oil goes in port (9) and out through port (2), (3) and (4) to pilot control valves
which in turn operates the main control valves.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 50 of 152

Section H-H Of Hydraulic Activation Control Valve (1)

(4) Port. (5) Spool. (9) Inlet port. (11) Plunger. (12) Limit switch. (13) Notch. (14) Housing.

Limit switch (12) is located in hydraulic activation control valve (1). The start switch can operate
only when the limit switch is turned ON, with hydraulic activation control lever (10) in the LOCK
position.

When lever (10) is in the UNLOCK position, spool (5) in valve (1) is held at the position shown in
the above left illustration. In this position, plunger (11) of switch (12) moves out to the left until its
end seats in notch (13). This turns OFF switch (12) which does not allow the start switch to operate.

When lever (10) is in the LOCK position, spool (5) turns clockwise to move plunger (11) in to the
right. (See the above right illustration.) This turns ON switch (12) which in turn allows the start
switch to operate.

Pilot Control Valves

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 51 of 152

Cross Section Of Pilot Control Valve (Implements And Swing)

(1) Lever. (2) Actuator plate. (3) Plunger. (4) Plunger. (5) Retainer. (6) Spring (metering). (7) Spring. (8) Return
chamber. (9) Return passage. (10) Passage. (11) Passage. (12) Passage. (13) Stem. (14) Stem. (15) Port. (16) Passage.
(17) Port. (18) Line (from control valve). (19) Line (to control valve). (20) Pilot pump.

Each pilot control valve has four valves which control two operations. For example, the left pilot
control valve has four valves, two for stick and two for swing.

When control lever (1) is moved to the left, actuator plate (2) tilts to the left. Actuator plate (2)
pushes down on plunger (3) against the force of springs (6) and (7). Stem (14) moves down with
plunger (3). The oil can now go through passages (16) and (11), and out port (15) to the main
control valve. The pressure of this oil on the end of the main control valve spool causes it to move
for implement or swing operation.

The oil at the opposite end of the main control valve spool for the operation comes back through
port (17), through passage (10) and then into return chamber (8) and back to tank.

Until plunger (3) makes direct contact with the top of stem (14), oil pressure in port (15) pushes up
against stem (14) and spring (6). As stem (14) moves up, passage (11) is closed and the flow of oil is
stopped to port (15) (the pressure remains in port (15)).

At this point, stem (14) has moved off retainer (5) and is being held in a pressure modulating
position. The stem has established a balance between the pressure in port (15) and the force of
spring (6).

When the control lever has moved approximately 90 percent of the distance for full implement or
swing actuation, plunger (3) makes direct contact with the top of stem (14). When this happens,

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 52 of 152

stem (14) is pushed down until passage (11) again opens to pilot pressure. Full pilot pressure now
goes to port (15).

When control lever (1) is released, spring (7) pushes up on plunger (3). Actuator plate (2) returns the
lever to HOLD position. Stem (14) moves up because retainer (5) has moved up with plunger (3)
and the force of spring (6) is less. The oil in port (15) can flow through return passage (9) and return
chamber (8) to tank.

Spring (7) maintains fine control operation.

Partial Cross Section Of Pilot Control Valve

(3) Plunger. (5) Retainer. (6) Spring. (7) Spring. (9) Return passage. (11) Passage. (14) Stem. (16) Passage. (21)
Passage. D: Diameter of stem (14) for return passage (9). d: Diameter of stem (14) for passage (11). E: Shoulder of stem
(14). F: Shoulder of stem (14). L: Length of spring (6) under compression. H: Distance of clearance.

Modulated Pilot Pressure

While the bottom of plunger (3) is not in direct contact with the top of stem (14), plunger (3)
compresses spring (6) through retainer (5) which in turn moves down stem (14). Any movement of
stem (14), under this condition, can control the pressure of the pilot oil which goes through passage
(11) to the main control valves. This gives modulation of the better pilot pressure to the spool of
main control valve for inching operation of implement or swing.

See Fig. A. When the force of spring (6) moves down stem (14), passage (11) opens. Part of the
pilot oil can go through passage (21) and out to the main control valve and moves the spool only
part of its travel distance against the force of the spring. This causes a slight increase in pressure
which works against the shoulders E and F of stem (14). Because the area of shoulder E is larger
than that of shoulder F, stem (14) moves up a small amount of its travel distance against the force of
spring (6). Return passage (9) partially opens and passage (11) is closed. (See Fig. B.)

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 53 of 152

Part of oil in passage (21) goes out through return passage (9) and there is a slight decrease in
pressure in passage (21).

When the pressure of moving up stem (14) is smaller than the force of spring (6), stem (14) comes
back to the position of Fig. A.

Stem (14) repeats up-and-down movements described above in a balanced condition between the
pressure in passage (21) and the force of spring (6).

During up-and-down movement of stem (14), a condition can occur that both return passage (9) and
passage (11) are instantly closed at a time (see Fig. C). This condition provides a certain length L of
spring (6) and also certain clearance H between the indented bottom face of plunger (3) and the top
of stem (4). At this point, the pressure in passage (21) establishes a balance with the force of spring
(6) at the time.

Further movement of plunger (3) decreases the length of spring (6) and establishes a new balance
between the force of spring (6) and the pressure in passage (21). The pressure in passage (21)
increases with an increase in the force of spring (6).

Thus, the force of spring (6) can control the pilot pressure as long as the clearance H exists.

Full Pilot Pressure

Further movement of plunger (3) (clearance H is zero) moves down stem (14). Spring (6) can no
longer control the pilot pressure. Full pilot pressure of 3450 kPa (500 psi) now goes to passage (21)
from passage (16).

Directional Travel

The pilot valves for travel operate like the pilot valves for the implements and swing. However,
there is a combination lever/foot pedal control for each of the left and right travel pilot control
valves. For more information on travel pilot control valve operation, see the section, Travel Control.

Proportional Reducing Valve

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 54 of 152

Cross Section Of Proportional Reducing valve

(1) Solenoid. (2) Valve.

The proportional reducing valve consists of solenoid (1) and reducing valve (2). While the engine is
operating, an electrical signal from the electronic controller energizes solenoid (1).

Solenoid (1) controls valve (2). Valve (2) allows a certain amount of pilot pressure through to the
pump regulator to control pump output. This pilot pressure to the regulator is called power shift
pressure. A decrease in engine speed increases the power shift pressure for decreased pump output.

An increase in engine speed decreases the power shift pressure for increased pump output.

Power Shift Pressure Increase

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 55 of 152

Cross Section Of Proportional Reducing Valve (Signal Current Increase)

(1) Solenoid. (3) Plunger. (4) Spool. (5) Passage (to pump suction line). (6) Passage (pilot pressure). (7) Spring. (8)
Passage (power shift pressure).

A decrease in engine speed increases the signal current to solenoid (1) which in turn gives increased
magnetic force to plunger (3). Plunger (3) pushes spool (4) down which overcomes the force of
spring (7) and the pressure in passage (8). Passage (6) then opens and the pilot pressure in passage
(6) can now go through passage (8) to the pump regulator as power shift pressure.

When power shift pressure increases, it destrokes the pump.

Power Shift Pressure Decrease

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 56 of 152

Cross Section Of Proportional Reducing Valve (Signal Current Decrease)

(1) Solenoid. (3) Plunger. (4) Spool. (5) Passage (to pump suction line). (6) Passage (pilot pressure). (7) Spring. (8)
Passage (power shift pressure).

An increase in engine speed decreases the signal current to solenoid (1). As the magnetic force given
to plunger (3) is smaller than the force of spring (7), plunger (3) moves up. Spool (4) follows
plunger (3) up and passage (5) is open. The power shift pressure in passage (8) then vents through
the passage in spool (4) and out through passage (5) to the pump suction line. The power shift
pressure decreases which in turn allows the pump to upstroke.

Hydraulic Schematic For Return Circuit

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 57 of 152

(1) Drain line (swing motor)

(2) Swing motor

(3) Left travel motor

(4) Right travel motor

(5) Makeup line

(6) Return line (control valves)

(7) Drain line (travel motor)

(8) Main control valves

(9) Pilot control valve (left travel)

(10) Pilot control valve (right travel)

(11) Pilot control valve (swing and stick)

(12) Hydraulic activation control valve

(13) Return line

(14) Pilot control valve (boom and bucket)

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 58 of 152

(15) Return line

(16) Return line

(17) Return line

(18) Drain passage

(19) Pilot oil manifold

(20) Slow return valve

(21) Oil cooler

(22) Drain line

(23) Return line

(24) Bypass check valve

(25) Drain line

(26) Hydraulic tank

(27) Rear pump

(28) Suction line

(29) Front pump

(30) Pilot pump

Return Circuit
Introduction

Control Valve Compartment (Viewed From Top)

(2) Swing motor. (5) Makeup line. (6) Return line.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 59 of 152

Pump Compartment
(19) Pilot oil manifold. (25) Drain line. (26) Hydraulic tank. (28) Suction line.

When main control valves (8) are in the Neutral position, the oil from front and rear pumps (29) and
(27) respectively flows through center bypass passages of main control valves (8). The oil returns to
hydraulic tank (26) through return line (6), slow return valve (20) and oil cooler (21).

Return oil from implements and motors flows through respective control valves to return line (6).

Case drain oil from the swing motor and travel motors goes through respective drain lines (1) and
(7) and combine at drain line (22). The oil then returns to the hydraulic tank.

Pilot return oil from pilot control valves (9) and (10) goes through return line (15) to return line (17).
Pilot return oil from pilot control valves (11) and (14) goes through respective return lines (16) and
(13) to hydraulic activation control valve (12). This oil then combines with the return oil from pilot
control valves (9) and (10) at return line (17). The combined pilot oil then goes through drain
passage (18) of pilot oil manifold (19) and drain line (25), and to suction line (28).

Makeup line (5) is a branch line of return line (6). It is connected to swing motor (2).

If a vacuum occurs in swing motor (2), the makeup line allows part of return oil to the swing motor.
This removes the vacuum condition and prevents cavitation.

Slow Return Valve And Oil Cooler Circuit

Radiator Compartment
(20) Slow return valve. (21) Oil cooler. (24) Bypass check valve. (31) Line (oil cooler inlet). (32) Line (oil cooler
outlet).

Slow return valve (20) is located in return line (6). This valve restricts oil flow to keep the pressure
in line (6) close to 340 kPa (50 psi). This causes part of oil in return line (6) to go to makeup line (5)
to remove the vacuum in swing motor (3).

See the section, Swing Control, for details on the makeup operation.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 60 of 152

Cross Section Of Bypass Check Valve

(24) Bypass check valve. (33) Line (bypass oil).

After the return oil flows through slow return valve (20), it separates into two lines; one to bypass
check valve (24) and the other to oil cooler (21).

When the oil temperature is very low, resistance to flow is high and causes an increase in oil
pressure. When the pressure increases close to 290 kPa (43 psi), bypass check valve (24) starts to
open. Most of the oil flows directly through the valve to hydraulic tank (26). The remainder of the
oil goes through oil cooler (21). This causes the oil temperature to increase and the pressure to
decrease.

An increase in oil temperature causes less resistance to flow. The opening of valve (24) becomes
smaller and there is more oil flow sent through oil cooler (21) which is bolted to the engine radiator.
Eventually, the valve is closed and all of return oil goes through cooler (21) to keep the correct oil
temperature.

Hydraulic Tank

Hydraulic Tank Compartment

(23) Return line. (26) Hydraulic tank. (34) Inlet. (35) Air breather.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 61 of 152

Cross Section Of Hydraulic Tank

(26) Hydraulic tank. (28) Suction line. (34) Inlet. (36) Return filter. (37) Relief valve. (38) Suction filter. (39) Return
chamber. (40) Tank chamber.

Return oil from oil cooler (21) and bypass check valve (24) goes through return line (23) and enters
return chamber (39) of tank (26) through inlet (34). The oil in return chamber (39) is passed through
return filter (36) for removing foreign substances before it enters tank chamber (40).

Relief valve (37) of return filter (36) opens when filter (36) is restricted. This bypasses return oil
directly to tank chamber (40) for protection.

The oil in tank (26) goes out through suction filter (38) and enters the pumps through suction line
(28). Filter (38) removes foreign substances contained in the tank oil.

Air breather (35) is provided near inlet (34). This prevents an increase or decrease in pressure in the
tank which could occur due to a change in oil level and/or temperature.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 62 of 152

Hydraulic Schematic For Boom Raise

(1) Boom cylinder

(2) Line

(3) Line

(4) Parallel feeder passage

(5) Return line

(6) Line

(7) Boom control valve

(8) Port

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 63 of 152

(9) Port

(10) Main control valves

(11) Load check valve (boom cylinder)

(12) Port

(13) Check valve

(14) Parallel feeder passage

(15) Return passage

(16) Boom control valve

(17) Port

(18) Pilot line (boom control valve)

(19) Port

(20) Pilot line (boom control valve)

(21) Pilot control valve (bucket and boom)

(22) Line

(23) Line

(24) Shock reducing valve for boom RAISE

(25) Front pump

(26) Rear pump

(27) Pilot pump

Boom, Bucket And Stick Control

Boom Control
Boom RAISE operation can be made in either operating speed, High or Low. The boom moves up in
High speed when the oil is supplied to the head end of boom cylinder (1) from both front and rear
pumps (25) and (26) respectively. The boom moves up in Low speed when oil is supplied only from
the front pump.

Boom LOWER operation uses only front pump oil.

Boom Raise (High Speed)

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 64 of 152

Main Control Valve Compartment (Viewed From Top Of Machine)

(7) Boom control valve. (16) Boom control valve.

When all control levers are in the Neutral position, oil from front pump (25) flows through parallel
feeder (circuits that have oil available at all times) passage (14) in main control valve (10). Passage
(14) supplies oil to boom control valve (7).

Oil from rear pump (26) flows through parallel feeder passage (4) in main control valve (10).
Passage (4) supplies boom control valve (16).

When the boom control lever is moved to its full RAISE position, the pilot oil in pilot control valve
(21) goes through pilot line (22) and shock reducing valve (24) and to line (23). Pilot oil flow then
divides. Oil flows through pilot line (18) to port (17) and through pilot line (20) to port (19).

Cross Section Of Boom Control Valve (7)

(8) Port. (9) Port. (11) Load check valve. (14) Parallel feeder passage. (15) Return passage. (17) Port. (28) Passage. (29)
Passage. (30) Spool. (31) Passage. (32) Spring.

The pilot oil through port (17) moves spool (30) in boom control valve (7) to the left. Now the front
pump oil from parallel feeder passage (14) goes through load check valve (11), passages (28), (31)
and out through port (8) to the head end of boom cylinder (1).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 65 of 152

Cross Section Of Boom Control Valve (16)

(4) Parallel feeder passage. (12) Port. (13) Check valve. (19) Port. (33) Passage. (34) Spool. (35) Passage. (36) Spring.

At the same time, pilot oil at port (19) of valve (16), moves spool (34) to the left. This allows rear
pump oil from parallel feeder passage (4) to go through passages (33), (35) and check valve (13) and
out through cylinder port (12) to line (6). The oil then combines with the front pump oil from valve
(7). The combined pump oil then goes through line (2) to the head end of boom cylinder (1).

Return oil from the rod end of boom cylinder (1) flows through line (3) to valve (7). The oil then
flows through passages (29), (15) and return line (5) to tank.

Boom Raise (Low Speed)

When the boom control lever is moved less than half of the travel distance for boom RAISE, full
pilot pressure will never be supplied to valve (7) and valve (16).

Under this condition, boom control valve (7) opens and valve (16) remains closed. The force of
spring (32) in valve (7) is less than the force for spring (36) in valve (16). Oil pressure will open
valve (7) before valve (16).

This allows only the front pump oil to go to the head end of boom cylinder (1). Without rear pump
oil, this slows down the cylinder rod movement for boom RAISE.

Shock Reducing Valve

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 66 of 152

Under Cab Floor

(24) Shock reducing valve (boom RAISE). (37) Shock reducing valve (boom LOWER). (38) Shock reducing valve
(stick OUT).

Cross Section Of Shock Reducing Valve (Check Valve Closed)

(24) Shock reducing valve (boom RAISE). (39) Check valve. (40) Spring. (41) Spring. (42) Port [pilot control valve (21)
side]. (43) Orifice. (44) Port [boom control valve (7) side]. (45) Passage.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 67 of 152

Shock reducing valve (24) for boom RAISE is one of three shock reducing valves located under the
cab floor. The remaining two shock reducing valves are for boom LOWER and stick OUT. All three
valves are contained in a valve block.

When boom raise operation is being stopped, shock reducing valve (24) restricts the pilot oil flow
returning from boom control valves (7) and (16). As a result, the spools in valves (7) and (16) slow
down in their return movement. Oil flow in pilot lines (18) and (20) slowly stops. This absorbs the
shock load before the cylinder rod stops travel.

When the shock reducing valve is in Neutral, passage (45) is closed. Ports (42) and (44) are
connected to each other through orifice (43).

Cross Section Of Shock Reducing Valve (Check Valve Open)

(39) Check valve. (40) Spring. (41) Spring. (42) Port [pilot control valve (21) side]. (44) Port [boom control valve (7)
side]. (45) Passage.

When the control lever is moved to the boom RAISE position, pilot oil is sent to port (42). Pressure
of the pilot oil moves check valve (39) to the left against the force of spring (40) and opens passage
(45). Pilot oil then goes out port (44) and through line (23) to boom control valves (7) and (16).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 68 of 152

Cross Section Of Shock Reducing Valve (Check Valve Closed)

(39) Check valve. (41) Spring. (42) Port [pilot control valve (21) side]. (43) Orifice. (44) Port [boom control valve (7)
side]. (45) Passage.

When the boom control lever is returned to the Neutral position, the pilot oil in control valves (7)
and (16) returns through lines (18) and (20) respectively to line (23). Oil flow combines in line (23)
and returns to port (44) of shock reducing valve (24).

The pressure of this pilot oil moves check valve (39) to the right against the force of spring (41) and
closes passage (45).

The pilot oil then goes through orifice (43) to port (42). Because the oil flow is restricted by orifice
(43), the oil flows at a lower rate and movements of the spools in control valves (7) and (16) slowly
stop at closed position. Also, the oil flow in line (2) in cylinder (1) slowly stops. This absorbs the
shock load before cylinder rod stops travel.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 69 of 152

Cross Section Of Shock Reducing Valve (Relief Position)

(39) Check valve. (42) Port [pilot control valve (21) side]. (44) Port [boom control valve (7) side]. (45) Passage.

Under the above condition, if there is a sudden increase in pressure at port (44) side, check valve
(39) moves further to the right. Passage (45) opens and allows the oil to go out of port (42). This
prevents a sudden increase in pressure at port (44) side.

The shock reducing valves for boom LOWER and stick OUT operate the same way as that described
for boom RAISE.

Boom Lower

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 70 of 152

Hydraulic Schematic (partial) (Boom Lower)

(1) Boom cylinder. (2) Line. (3) Line. (5) Return line. (7) Boom control valve. (8) Port. (9) Port. (10) Main control
valves. (11) Load check valve. (14) Parallel feeder passage. (15) Return passage. (25) Front pump. (26) Rear pump. (27)
Pilot pump. (44) Port. (45) Orifice. (46) Return passage.

When the boom is LOWERED, only the oil from front pump (25) is used. It flows through parallel
feeder passage (14) and boom control valve (7) to the rod end of boom cylinder (1).

When the control lever is moved to the boom LOWER position, pilot oil goes to port (44) of boom
control valve (7).

Cross Section Of Boom Control Valve (Lower Position)

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 71 of 152

(8) Port. (9) Port. (11) Load check valve. (14) Parallel feeder passage. (15) Return passage. (30) Spool. (44) Port. (45)
Orifice. (47) Passage.

The pilot oil through port (44) moves spool (30) to the right. The front pump oil in parallel feeder
passage (14) goes through load check valve (11), passage (47) and out through port (9). The oil then
goes through line (3) to the rod end of boom cylinder (1).

The return oil from the head end of the boom cylinder returns through line (2) to valve (7). The oil
then goes through orifice (45) of spool (30), return passages (15) and (46) to return line (5) for boom
LOWER. Because the flow of return oil is restricted by orifice (45), movement of the boom cylinder
rod is slowed down so that the boom can lower at a speed based on the flow rate of front pump oil.

Cylinders

Cross Section Of Cylinders

(1) Head end port. (2) Boom cylinder. (3) Cylinder. (4) Piston rod. (5) Snubber. (6) Piston. (7) Rod end port. (8) Stick
cylinder. (9) Snubber. (10) Snubber. (11) Bucket cylinder.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 72 of 152

Snubber Operation (Rod Extending)

(9) Snubber. (12) Passage.

When boom cylinder (2) comes close to the end of extension stroke, passage (12) is restricted by
snubber (9). The rod end return oil develops a higher pressure, causing the piston rod to slow down
before it stops.

Snubber Operation (Rod Retracting)

(10) Snubber. (13) Passage.

Also, when stick cylinder (8) comes close to the end of retraction stroke, passage (13) is restricted
by snubber (10). Return oil from this side develops a higher pressure so the same action as on the
extension stroke slows down the movement of the piston rod. This absorbs the shock load at the end
of the piston rod movement.

Bucket Control

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 73 of 152

Hydraulic Schematic (Partial) (Bucket CLOSE Position)

(1) Line. (2) Bucket cylinder. (3) Return line. (4) Main control valves. (5) Line. (6) Port. (7) Port. (8) Port. (9) Load
check valve. (10) Bucket control valve. (11) Orifice. (12) Return passage. (13) Parallel feeder passage. (14) Port. (15)
Front pump. (16) Rear pump. (17) Pilot pump.

When the bucket is operated for both CLOSE and DUMP, only the oil from front pump (15) is
supplied to the bucket cylinder. Oil from both pumps never combine for this operation.

Cross Section Of Bucket Control Valve (CLOSE Position)

(6) Port. (7) Port. (8) Port. (9) Load check valve. (11) Orifice. (12) Return passage. (13) Parallel feeder passage. (14)
Port. (18) Passage. (19) Passage. (20) Spool.

When the control lever is moved to the bucket CLOSE position, pilot oil goes to port (14) and
moves spool (20) to the left.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 74 of 152

Front pump oil in parallel feeder passage (13) goes through load check valve (9), passage (19) and
out port (7) of bucket control valve (10). The oil then goes through line (5) to the bucket cylinder
head end for bucket CLOSE.

The return oil in the rod end goes through line (1) to valve (10). The oil then goes through orifice
(11) of spool (20), return passage (12) and through return line (3) to tank. Because the return oil
flow is restricted by orifice (11), movement of piston rod slows down and the bucket can close based
on the flow rate of the front pump oil.

When the control lever is moved to the bucket DUMP position, the pilot oil goes to port (6) and
moves spool (20) to the right.

Front pump oil in parallel feeder passage (13) goes through load check valve (9), passage (18) and
out port (8) of valve (10). The oil then goes through line (1) to the bucket cylinder rod end for
bucket DUMP.

Hydraulic Schematic For Stick Out

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 75 of 152

(1) Stick cylinder

(2) Line

(3) Line

(4) Return line

(5) Port

(6) Port

(7) Port

(8) Return passage

(9) Main control valves

(10) Stick control valve

(11) Port

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 76 of 152

(12) Load check valve

(13) Center bypass passage

(14) Return passage

(15) Stick control valve

(16) Passage

(17) Center bypass passage

(18) Passage

(19) Check valve

(20) Passage

(21) Port

(22) Line

(23) Pilot control valve (swing and stick)

(24) Line

(25) Line

(26) Line

(27) Shock reducing valve (stick OUT)

(28) Line

(29) Line

(30) Shuttle valve

(31) Line

(32) Front pump

(33) Rear pump

(34) Pilot pump

Stick Control
When the stick is controlled for both stick OUT (stick cylinder rod RETRACTION) and IN (stick
cylinder rod EXTENSION), oil from front and rear pumps (32) and (33) is supplied to stick cylinder
(1).

Shock reducing valve (27) for stick OUT is located between pilot lines (29) and (31). This gives a
cushion effect to the cylinder rod before it stops travel for stick OUT. (See the section, Boom
Control.) No shock reducing valve is provided for stick IN.

Stick Out

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 77 of 152

Cross Section of Stick Control Valve (15) (Stick OUT)

(5) Port. (6) Port. (7) Port. (8) Return passage. (12) Load check valve. (16) Passage. (17) Center bypass passage. (21)
Port. (35) Passage. (36) Passage. (37) Spool.

When the control lever is moved to the stick OUT position, pilot oil from pilot control valve (23)
goes through line (29), shock reducing valve (27) and line (31) and (22) to port (7) of stick control
valve (15). This moves spool (37) to the right.

Oil from rear pump (33) flows through center bypass passage (17) to stick control valve (15). The
oil then goes through load check valve (12), passage (35) and out through port (6). The oil flows
through line (3) to the rod end of stick cylinder (1).

Main Control Valve Compartment (Viewed From Top Of Machine)

(10) Stick control valve. (15) Stick control valve.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 78 of 152

Cross Section Of Stick Control Valve (10) (Stick OUT)

(11) Port. (13) Center bypass passage. (14) Return passage. (18) Passage. (19) Check valve. (38) Passage. (39) Passage.
(40) Spool.

At the same time, pilot oil also flows from pilot control valve (23) through lines (31), (28), shuttle
valve (30) and line (26) to port (11) of stick control valve (10). This moves spool (40) to the right to
close passage (39) which in turn blocks the oil flow from center bypass passage (13) to return
passage (14).

All of front pump oil in center bypass passage (13) now goes through passage (38) and check valve
(19) to passage (18). The oil then combines with the rear pump oil in passage (16).

The return oil from the stick cylinder head end flows through line (2) to port (5) of valve (15).
Return oil flows through passage (36), return passage (8) and return line (4) to the tank.

Stick IN
When the control lever is moved to the stick IN position, pilot control valve (23) sends the pilot oil
to port (11) of valve (10) and port (21) of valve (15).

In the same manner as for stick OUT, the front pump oil goes in valve (15) through passage (18) and
the rear pump oil goes in valve (15) through center bypass passage (17). The oil from both pumps
combine with each other in passage (16).

The combined oil then goes out port (5) and through line (2) to the stick cylinder head end for stick
IN.

Shuttle Valve

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 79 of 152

Shuttle Valve Operation (Stick OUT)

(30) Shuttle valve. (40) Ball valve. (41) Pilot oil manifold. (42) Passage. (43) Port. (44) Passage.

Shuttle valve (30) is installed in pilot oil manifold (41). It allows pilot oil flow to stick control valve
(10) when the stick is operated for both stick OUT and IN. Port (43) is the pilot oil inlet when the
stick cylinder is retracted (stick OUT). Passage (42) is the pilot oil passage when the stick cylinder is
extended (stick IN).

In stick OUT operation, the pilot oil goes in through passage (43) to move ball valve (40) to the right
and out through passage (44). The oil then goes through line (26) to port (11) of valve (10).

In stick IN operation, the pilot oil goes in through passage (42) to move ball valve (40) to the left
and out through passage (44). The oil then goes through line (26) to port (11) of valve (10) in the
same manner as that for stick OUT.

Hydraulic Schematic for Swing Right

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 80 of 152

(1) Swing parking brake.

(2) Swing motor rotary group.

(3) Swing motor.

(4) Check valve.

(5) Relief valve.

(6) Makeup line.

(7) Pilot line (swing parking brake).

(8) Line.

(9) Line.

(10) Return line.

(11) Pressure switch (swing parking brake).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 81 of 152

(12) Main control valves.

(13) Port.

(14) Port.

(15) Port.

(16) Parallel feeder passage.

(17) Stick control valve.

(18) Return passage.

(19) Left travel control valve.

(20) Pilot passage.

(21) Right travel control valve.

(22) Attachment control valve.

(23) Boom control valve.

(24) Bucket control valve.

(25) Load check valve.

(26) Orifice.

(27) Swing control valve.

(28) Pilot passage.

(29) Pilot line.

(30) Port.

(31) Pilot line.

(32) Pilot control valve (swing and stick).

(33) Line.

(34) Drain line.

(35) Solenoid valve III.

(36) Drain passage.

(37) Pilot oil manifold.

(38) Passage.

(39) Slow return valve.

(40) Drain line.

(41) Front pump.

(42) Rear pump.

(43) Pilot pump.

Swing Control

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 82 of 152

Introduction
Swing motor (3) is driven by the oil from rear pump (42). When the left control lever is moved to
the right or left, the pilot oil flows to swing parking brake (1). Swing brake (1) is released first, and
then swing motor rotary group (2) starts to rotate.

The swing drive reduces the motor speed into two stages and then rotates the upper structure.

Swing Right Operation

Main Control Valve Compartment

(8) Line. (11) Pressure switch (swing parking brake). (27) Swing control valve.

Swing Control Valve (Swing Right Position)

(13) Port. (14) Port. (15) Port. (16) Parallel feeder passage. (18) Return passage. (25) Load check valve. (30) Port. (44)
Passage. (45) Passage. (46) Passage. (47) Spool.

When the control lever is moved to the swing RIGHT position, the pilot oil from pilot control valve
(32) goes through port (30) of swing control valve (27). Spool (47) moves to the left and opens
passages (45) and (46).

The rear pump oil enters swing control valve (27) through parallel feeder passage (16) and load
check valve (25). The oil then goes through passages (44) and (46) and out through port (13). From
port (13), oil flows through line (8) to swing motor rotary group (2).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 83 of 152

Return oil from group (2) goes through line (9) and enters valve (27) through port (14). The oil then
goes through passage (45) and return passage (18) to return line (10). Rotary group (2) rotates and
causes the upper structure to swing to the right.

Swing Parking Brake

On Position

Pilot oil leaves pilot oil manifold (37) through passage (38) and enters main control valves (12)
through line (33). Oil then goes through orifice (26) to pilot passage (28). During pilot oil flow,
orifice (26) causes lower pressure in passage (28).

With main control valves (12) in Neutral, pilot passage (28) connects in series the control valves for
swing (27), stick (17), attachment (22), boom (23) and bucket (24). Now the pilot oil in passage (28)
goes through all of these valves and to drain line (34). The oil in drain line (34) leaves pilot oil
manifold (37) through passage (36). It then goes through drain line (40) to the pump suction line.

Pressure Switch
(11) Switch. (48) Port.

With the control valves in neutral, the oil pressure in passage (20) which is a branch of passage (28)
is kept low. As a result, pressure switch (11) located at the end of passage (20) is OFF and does not
energize solenoid valve III (35).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 84 of 152

Pump Compartment
(35) Solenoid valve III.

Solenoid Valve Not Energized Position

(7) Pilot line. (35) Solenoid valve III. (36) Drain passage. (38) Passage. (49) Solenoid. (50) Port. (51) Drain port. (52)
Port. (53) Spring. (54) Spool.

Pilot line (7) for swing parking brake (1) is connected to port (52) of solenoid valve III (35). When
solenoid (49) is not activated, port (52) is open to drain port (51). The pilot oil in line (7) goes
through drain passage (36) in pilot manifold (37). It then flows through drain line (40) to the pump
suction line. With no pilot pressure at parking brake (1), the swing parking brake remains ON.

Off Position

Operation of any control valves other than travel closes passage (28) and increases oil pressure in
passage (28). The increased pilot pressure goes to port (48) of pressure switch (11). Switch (11)
turns ON and energizes solenoid valve III (35).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 85 of 152

Solenoid Valve Energized Position

(49) Solenoid. (50) Port. (51) Port. (52) Port. (53) Spring. (54) Spool.

When solenoid (49) is energized, spool (54) moves to the left and port (50) is open to port (52). The
pilot oil coming from passage (38) in pilot manifold (37) enters port (50) and leaves through port
(52). The oil then goes through pilot line (7) to parking brake (1). This releases the parking brake.

Activation of travel valves (19) or (21) does not close passage (28). The parking brake remains ON.

Because passage (28) is closed before passage (46) is opened in swing control valve (27), swing
motor (3) operates only after parking brake (1) has been released by the pilot pressure from solenoid
valve (35).

Solenoid valve (35) is turned OFF by a timer relay four seconds after a swing or implement
operation is completed. This makes sure the parking brake remains released until the motor comes to
a stop.

For swing left operation, pilot oil is supplied to port (15) of swing control valve (27) and spool (47)
moves to the right. The rear pump oil in parallel feeder passage (16) goes out through port (14). It
flows through line (9) to motor rotary group (2). In this case, the supply and return ports are reverse
of swing right operation. This causes the upper structure to swing to the left.

For information on operation of the swing parking brake, see the following section, Swing Motor.

Swing Motor

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 86 of 152

Cross Section Of Swing Motor

(1) Cam plate. (2) Retainer plate. (3) Piston. (4) Disc. (5) Plate. (6) Piston. (7) Balance plate. (8) Spring. (9) Relief valve.
(10) Cover. (11) Makeup port. (12) Passage. (13) Passage. (14) Shaft. (15) Drain port. (16) Shoe. (17) Barrel. (18)
Housing. (19) Pilot port (swing brake release). (20) Relief valve. (21) Plug. (22) Piston. (23) Check valve. (24) Spring.
(25) Plug. (26) Plug. (27) Plug. (28) Spring. (29) Spring. (30) Check valve. (31) Passage. (32) Port. (33) Passage. (34)
Port. (35) Passage.

Introduction

The swing motor may be divided into the following three groups;

1. Rotary group, which consists of barrel (17), pistons (3), shoes (16), retainer plate (2) and
shaft (14).
2. Parking brake group, which consists of discs (4), plates (5), piston (6) and springs (8).
3. Relief and makeup valve group, which consists of relief valves (9) and (20), plug (21),
piston (22), springs (24), plugs (25), (26) and (27), springs (28), (29) and check valves (23),
(30).

Operation

The oil from the rear pump passes through the swing control valve which directs oil to port (32) or
(34) of the swing motor.

For swing right, pump oil enters port (34) and goes through passage (35) in cover (10), passage (12)
in balance plate (7) and through passage (13) in barrel (17).

Pump oil in barrel (17) gives pressure to piston (3). Piston (3) in turn forces shoe (16) against cam
plate (1). Along with piston (3), shoe (16) slides down on the inclined surface of cam plate (1) from
the top dead center to bottom dead center.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 87 of 152

Motor Passages (Viewed From Cover Side)

(12) Passage (in balance plate). (13) Passage (in barrel). (31) Passage. (32) Port. (34) Port. (35) Passage. (36) Passage (in
balance plate). (37) Counterclockwise turn.

The force created by shoe (16) and piston (3) against cam plate (1) causes barrel (17) to rotate
counterclockwise. After passing through the bottom dead center position passage (13) to piston (3)
opens to passage (36) in balance plate (7). Oil now returns to the hydraulic tank. Piston (3) and shoe
(16) continue to move up on the inclined surface of cam plate (1) as barrel (17) continues to turn
counterclockwise.

When the rear pump oil is supplied to port (32) for swing left, the supply and return ports are
reversed. Barrel (17) and shaft (14) turn counterclockwise.

The case drain oil returns through drain port (15) of housing (18) to the hydraulic tank.

Swing Parking Brake

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 88 of 152

Parking Brake
(1) Housing. (2) Barrel. (3) Piston. (4) Disc. (5) Plate. (6) Pilot port. (7) Piston. (8) Spring. (9) Cover.

The swing parking brake group is located between housing (1) and cover (9). It is made up of discs
(4), plates (5), piston (7) and springs (8).

Teeth on the inner circumference of disc (4) engage with splines on barrel (2). Teeth on the outer
circumference of plate (5) engage with splines on the inner circumference of housing (1).

When there is no pump oil supplied to the swing motor, discs (4), plates (5) and piston (3) are
mechanically locked to housing (1) by the force of springs (8). Through discs (4) and plates (5),
barrel (2) is also held to housing (1). As a result, the upper structure is locked to the lower structure
to present rotation of the upper structure.

Before oil from the rear pump is supplied to the swing motor, pilot oil passes through the solenoid
valve III and enters pilot port (6) of the swing motor. The pressure of the pilot oil moves piston (7)
away from discs (4) and plates (5) against the force of springs (8). When the force that holds the
discs and plates together is released, the upper structure is then released for the swing operation.

Relief/Makeup Operation

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 89 of 152

Swing Circuit Schematic (Partial)

(1) Passage. (2) Motor rotary group. (3) Makeup port. (4) Check valve. (5) Passage. (6) Passage. (7) Swing motor. (8)
Makeup line. (9) Check valve. (10) Relief valve. (11) Relief valve. (12) Passage. (13) Port. (14) Port. (15) Check valve.
(16) Slow return valve. (17) Return line. (18) Main control valves. (19) Orifice. (20) Return line. (21) Hydraulic tank.

Swing Motor And Control Valve Compartment

(7) Swing motor. (8) Makeup line. (10) Relief valve. (11) Relief valve. (17) Return line.

Relief Valve

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 90 of 152

Relief Valve
(5) Passage. (10) Relief valve. (12) Passage. (22) Piston chamber. (23) Piston. (24) Spring. (25) Plug. (26) Orifice. (27)
Spring chamber. (28) Poppet. (29) Spring. (30) Passage. (31) Orifice.

When the swing control lever is moved back to Neutral during swing right operation, inlet and outlet
ports of the swing control valve are closed. As a result, oil flow is blocked at supply port (13) and
return port (14) of swing motor (7).

For a short period of time after a stop operation, the motor continues to rotate because of the mass of
the upper structure. It attempts to draw oil from port (13) and force it out port (14). Since port (14) is
closed, the pressure of the blocked oil in passage (5) increases. The increased pressure in passage (5)
forces poppet (28) to open against the force of spring (29) in relief valve (10). Oil then flows
through passage (12) and check valve (4) to passage (6). From passage (6), oil enters motor rotary
group (2). During this operation, the force of the rotating upper structure is absorbed as the swing
motor comes to a stop.

As the pressure in passage (5) increases, the pressure oil goes to piston chamber (22) through orifice
(31), passage (30) and orifice (26).

As the pressure in piston chamber (22) overcomes the force of spring (24), piston (23) moves to the
right until it is stopped by plug (25). This decreases the pressure in piston chamber (22) and spring
chamber (27). In a very short time oil forces piston (23) to the right, poppet (28) can be opened by
the pressure slightly lower than the relief pressure setting. As the movement of piston (23) has been
completed, the pressure in spring chamber (27) increases which in turn increases the pressure in
passage (5) to the relief pressure setting. It is not until the full relief pressure setting is reached that
all of the oil is allowed to flow out of relief valve (10) to passage (12).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 91 of 152

Because of this relief action in two stages, no peak pressure builds up when relief valve (10) opens.
Less shock load occurs when the swing motor stops.

At the start of swing right operation, the swing motor does not immediately accelerate to speed
because of the mass of the upper structure. Part of the pressure oil flows past the poppet in relief
valve (10) to makeup port (3). This gives smoother acceleration at the start of a swing operation.

Oil Makeup

As described previously, when rotation of the swing motor is stopped, all ports in the swing control
valve become blocked. There is no pump oil sent to swing motor (7).

As the upper structure attempts to continue rotating, part of the oil in swing motor (7) is lost in the
form of internal leakage. Because of this oil loss, a vacuum could occur at port (13) side. To prevent
this, oil from return line (17) goes through makeup line (8), makeup port (3), passage (1), check
valve (4) and passage (6) into motor rotary group (2).

Slow Return Valve

Radiator Compartment
(16) Slow return valve. (17) Return line.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 92 of 152

Cross Section Of Slow Return Valve

(15) Check valve. (16) Slow return valve. (17) Return line. (19) Orifice. (20) Return line.

Slow return valve (16) is located downstream of return line (17). Valve (16) makes it possible to
makeup lost oil during swing stop.

However, when all of main control valves (18) are in Neutral, the oil from the front and rear pumps
goes through return line (17) to tank (21). Slow return valve (16) gives a resistance to the oil flow in
return line (17) to maintain the oil pressure at 345 kPa (50 psi).

When there is not enough oil to the swing motor, this return line back pressure adds oil immediately
to the motor rotary group through makeup port (3) and passage (6).

Orifice (19) in check valve (15) of valve (16) allows makeup oil from return line (20) to go to return
line (17). The oil then goes through makeup line (8) and enters the swing motor.

When the motor speed is decreased during a high speed right swing by moving the swing control
lever partially to Neutral, oil supply from port (13) decreases. At the same time, oil flow keeps going
out through port (14) to return line (17) because the swing control valve is partially open. However,
on port (14) side, the pressure is lower than the relief setting of valve (10). So, valve (10) is kept
closed and there is no makeup oil sent to passage (6) through check valve (4). As a result, a vacuum
develops at port (13) side. In this situation, check valve (4) and slow return valve (16) function to
supply makeup oil to the swing motor.

If the swing motor is stopped or decelerated during a swing in the opposite direction when oil is
supplied through port (14), check valve (9) instead of check valve (4) operates to prevent vacuum in
swing motor (7).

Swing Drive

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 93 of 152

Cross Section of Swing Drive

(1) Swing motor. (2) Output shaft (swing motor). (3) First stage carrier. (4) First stage planetary gear. (5) First stage sun
gear. (6) Second stage carrier. (7) Ring gear. (8) Second stage sun gear. (9) Second stage planetary gear. (10) Roller
bearing. (11) Housing. (12) Roller bearing. (13) Pinion shaft. (14) Swing bearing. (15) Ring gear.

The swing drive is a series of planetary gears which reduce the rotating speed of swing motor (1).
The swing motor is bolted on the swing drive which is bolted to the upper structure. The swing drive
output pinion shaft (13) provides motion to the upper structure by rotating around a large ring gear
attached to the lower structure.

The swing drive is divided into two groups.

1. The first group functions as a double reduction of motor speed. The first stage reduction
consists of first stage sun gear (5), first stage planetary gears (4), first stage carrier (3) and ring
gear (7).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 94 of 152

The second stage reduction consists of second stage sun gear (8), second stage planetary gears
(9), second stage carrier (6) and ring gear (7).

2. The second group functions as the drive for reduced motor speed output. It consists of
pinion shaft (13) which is supported by roller bearings (10) and (12) located in housing (11).

First Stage Planetary Gear Rotation

(3) First stage carrier. (4) First stage planetary gear. (5) First stage sun gear. (7) Ring gear. (16) Shaft (First stage
planetary gear).

Swing motor output shaft (2) is splined to first stage sun gear (5). First stage planetary gears (4) of
first stage carrier (3) are in mesh with first stage sun gear (5).

As swing motor shaft (2) rotates sun gear (5) counterclockwise, planetary gears (4) rotate clockwise
on their shafts (16), moving counterclockwise around ring gear (7) which is bolted to housing (11).
This in turn rotates carrier (3) counterclockwise.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 95 of 152

Cross Section of Swing Drive (Partial)

(3) First stage carrier. (4) First stage planetary gear. (5) First stage sun gear. (6) Second stage carrier. (7) Ring gear. (8)
Second stage sun gear. (9) Second stage planetary gear. (10) Roller bearing. (12) Roller bearing. (13) Pinion shaft.

Splines on the inner circumference of first stage carrier (3) engage with the splines on second stage
sun gear (8). This causes gear (8) to rotate counterclockwise. In turn, second stage planetary gears
(9) turns clockwise on their shafts, moving counterclockwise around ring gear (7) in the same
manner as in the first stage. This turns second stage carrier (6) counterclockwise. The splines of
pinion shaft (13) engage with splines on the inner circumference of carrier (6). This causes shaft
(13) to rotate counterclockwise.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 96 of 152

Pinion Shaft (13) Rotation

(13) Pinion shaft. (15) Ring gear. (17) Location of moving pinion shaft.

Pinion shaft (13) engages with ring gear (15) on the inner circumference of swing bearing (14). As
pinion shaft (13) rotates counterclockwise, it moves clockwise around ring gear (15) which is bolted
to the lower structure. This causes the upper structure to swing to the right (clockwise).

Hydraulic Schematic For Forward Travel

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 97 of 152

(1) Travel motor (left)

(2) Motor rotary group

(3) Travel motor (right)

(4) Passage

(5) Parking brake

(6) Passage

(7) Brake pilot valve

(8) Passage

(9) Counterbalance spool

(10) Check valve

(11) Passage

(12) Line

(13) Line

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 98 of 152

(14) Rotary joint

(15) Line

(16) Return line

(17) Port

(18) Port

(19) Line

(20) Passage

(21) Left travel control valve

(22) Return passage

(23) Right travel control valve

(24) Passage

(25) Center bypass passage

(26) Pilot line

(27) Port

(28) Pilot line

(29) Pilot control valve (left travel)

(30) Pilot control valve (right travel)

(31) Front pump

(32) Rear pump

(33) Pilot pump

Travel Control
Introduction
Controls For Travel

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED BY... Page 99 of 152

Illustration Of Travel Operation

(1) Travel motor (left track). (3) Travel motor (right track). (36) Forward direction. (37) Control lever/pedal (left track).
(38) Idler wheel location. (39) Control lever/pedal (right track). (40) Cab. (41) Reverse direction.

The direction of travel (FORWARD or REVERSE) is relative to the position of the lower structure.
For normal travel, idler wheel (38) is positioned in front of cab (40) and travel motors (1) and (3) to
the rear of the cab. With the machine in the normal position of travel, move the control levers/pedals
(37) and (39) forward. Then the machine will travel in direction (36). This movement is called
FORWARD travel. When control levers/pedals (37) and (39) are moved to the rear, the machine
travels in direction (41). This direction is called REVERSE travel.

When cab (40) is turned 180°, travel motors (1) and (3) will be positioned in front of the cab. The
direction of travel and operation of control levers/pedals (37) and (39) are reverse to when the
machine is in the normal travel direction.

Left travel control lever/pedal (37) operates left travel motor (1) for the left track. Right travel
control lever/pedal (39) operates right travel motor (3) for the right track.

Pivot Turn

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 100 of 152

Pivot And Spot Turn Illustration

(37) Control lever/pedal (left track). (39) Control lever/pedal (right track). (42) Track (left). (43) Track (right). (44) Pivot
turn. (45) Spot turn.

NOTE: The following explanations are for normal travel direction.

When only one of control levers/pedals (37) or (39) is moved forward, the respective track travels
forward. Since the opposite track is stationary, the machine turns with the stationary track as its axis
(pivot point). This is called a pivot turn.

A pivot turn is made when the traveling direction of the machine is to be changed.

Spot Turn

A spot turn is made when the traveling direction of the machine is to be changed in a narrow place.

To complete a spot turn operation, move one control lever/pedal (37) to the rear and the other
control lever/pedal (39) forward at the same time. Then one track (42) travels to the rear and the
other track travels forward. The machine makes a minimum radius (spot) turn with its center as its
axis.

Forward Travel Operation

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 101 of 152

Main Control Valve Compartment

(21) Left travel control valve. (23) Right travel control valve.

When travel control levers are operated, the pilot oil from pilot control valves (29) and (30) shift the
spools in travel control valves (21) and (23). Valves (21) and (23) allow oil flow from rear pump
(32) and front pump (31) to rotary joint (14). The rotary joint transfers oil from the rotating upper
structure to the lines in the lower structure. The oil flows to left and right travel motors (1) and (3)
respectively.

NOTE: Since right and left travel controls function the same, explanations are given relative to left
travel control.

Cross Section Of Travel Control Valve (Left Track)

(17) Port. (18) Port. (20) Passage. (22) Return passage. (24) Passage. (25) Center bypass passage. (27) Port. (46) Spool.
(47) Passage. (48) Passage.

The pilot oil from pilot control valve (29) goes through pilot line (26) to port (27) of travel control
valve (21). Spool (46) moves to the left to close the opening between center bypass passage (25) and
passage (48). This allows rear pump oil in center bypass passage (25) to go through passages (24)
and (20), and out through port (17). From port (17), oil goes through line (15), rotary joint (14), line
(13) and passage (11), and enters motor rotary group (2) through check valve (10).

At the same time, rear pump oil flows through counterbalance spool (9). The oil then goes through
passage (8), brake pilot valve (7) and passage (4) to parking brake (5). Brake (5) releases to allow
rotation of left travel motor (1) in the forward direction.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 102 of 152

Return oil from motor rotary group (2) flows through passage (6), counterbalance spool (9) and line
(12) to rotary joint (14). Oil then goes through line (19) and port (18) into left travel control valve
(21). The oil goes through passage (47) and return passage (22), and back to the hydraulic tank
through return line (16).

Oil from front pump (31) turns right travel motor (3). Operation of right track is the same as that
described for left track.

The travel alarm (if equipped) is located under the cab floor. When the travel control lever/pedal is
activated for either forward or reverse travel, the pressure oil is sent to the pressure switch to sound
the alarm intermittently.

Pilot Control Valve (Travel)

Cross Section Of Pilot Control Valve (Travel)

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 103 of 152

(1) Control lever/pedal. (2) Actuator plate. (3) Plunger. (4) Retainer. (5) Spring. (6) Spring. (7) Stem. (8) Passage. (9)
Passage. (10) Spring. (11) Stem. (12) Port (pilot oil return). (13) Return chamber. (14) Passage. (15) Passage. (16) Port
(from pilot pump). (17) Passage. (18) Port (to travel control valve). (19) Passage. (20) Passage. (21) Passage. (22) Port
(to travel control valve).

When control lever/pedal (1) is moved to the FORWARD travel position, actuator plate (2) pushes
down on plunger (3) and retainer (4) against the force of springs (5) and (6). Until the bottom face of
plunger (3) is in direct contact with the top of stem (7), stem (7) moves down against the force of
spring (6) to open passage (19). After the bottom face has made contact with the top of stem (7),
plunger (3) directly moves down stem (7) to open passage (19).

The oil from pilot port (16) goes through passages (21), (19), (20) and (9), and out port (18) to the
travel control valve. The pressure of this oil on the end of the travel valve spool causes it to move
into the FORWARD position.

The oil from the chamber at the opposite end of the main control valve for travel comes back
through port (22), through passage (17), (15) and (14). Then the oil flows into return chamber (13)
and back to the tank through port (12).

Until the bottom face of plunger (3) makes direct contact with the top of stem (7), oil pressure in
port (18) pushes up against stem (7) and spring (6). Any increase in pressure in port (18) will
increase the force against stem (7) and spring (6). As stem (7) moves up, passage (19) is closed and
the flow of oil is stopped to port (18). [The pressure remains in port (18).] At this point, stem (7) has
moved off retainer (4) and is being held in a pressure modulating position. The stem has established
a balance between the pressure in port (18) and the force of spring (6). For details of how spring (6)
operates, see "Pilot Control Valve for Implements and Swing in the section, "Pilot Circuit".

When the control lever/pedal is moved forward almost full travel distance, plunger (3) makes direct
contact with the top of stem (7). This fully opens passage (19) so that passage (20) is again open to
pilot pressure. Full pilot pressure of approximately 3450 kPa (500 psi) now goes to port (18).

When the lever/pedal is released, spring (5) pushes up on retainer (4) and plunger (3). Actuator plate
(2) returns the lever to the NEUTRAL position. Stem (7) moves up because retainer (4) has moved
up with plunger (3) and the force of spring (6) is less. The oil in port (18) can now flow through
passage (9), (20), (8) and return chamber (13) and back to tank.

When lever/pedal (1) is moved to the reverse travel position, operation is the same as that described
for FORWARD.

Travel Motor

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 104 of 152

Travel Motor
(1) Drain port. (2) Port. (3) Port. (4) Shaft (motor). (5) Retainer. (6) Ball retainer. (7) Spacer. (8) Housing (motor). (9)
Spring. (10) Passage. (11) Passage. (12) Brake pilot valve. (13) Cover. (14) Passage. (15) Valve plate. (16) Passage. (17)
Travel drive. (18) Swash plate. (19) Shoe. (20) Barrel. (21) Piston. (22) Friction plate. (23) Steel plate. (24) Brake
piston. (25) Spring. (26) Check valve. (27) Counterbalance valve. (28) Counterbalance spool. (29) Retainer. (30) Spring.
(31) Plug.

Left Travel Motor

(1) Drain port. (2) Port. (3) Port. (27) Counterbalance valve. (32) Travel motor.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 105 of 152

The travel motor can be divided into the following three groups.

1. Rotary group; Consists of barrel (20), shaft (4), pistons (21), shoes (19), retainer (5), spring
(9), spacer (7) and ball retainer (6).
2. Counterbalance group; Consists of counterbalance spool (28), retainer (29), spring (30),
plug (31) and check valve (26).
3. Parking brake group; Consists of brake pilot valve (12), brake piston (24), friction plates
(22), steel plates (23) and spring (25).

Depending on travel direction, pump oil goes into the travel motor through port (2) or (3) and is
forced out through port (3) or (2).

The case drain oil that has leaked from the sliding surfaces and clearances returns to tank through
drain port (1) of cover (13).

Supply oil from the rear pump goes in the left travel motor through port (3) during forward travel.
On the right motor, port (3) serves as the supply oil port during reverse travel.

Inlet And Outlet Ports [Viewed From Cover (13) Side]

(14) Passage (valve plate). (16) Passage (barrel). (33) Passage (valve plate).

The oil from port (3) goes through passage (11) and check valve (26) to passage (10). The oil then
goes through passage (14) in valve plate (15) to passage (16) in barrel (20) to force piston (21)
down. Piston (21) causes shoe (19) to slide on the surface of swash plate (18) from top dead center
to bottom dead center. Piston (21) and shoe (19) rotate counterclockwise along with barrel (20).

The oil that is forced out by the pistons situated at the outlet side goes through passage (16) in barrel
(20) and passage (33) in valve plate (15), and out through port (2).

Shaft (4) which is splined to barrel (20) turns counterclockwise for FORWARD travel.

In REVERSE travel, port (3) serves as the oil return port and port (2) serves as the supply port. The
left travel motor rotates clockwise.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 106 of 152

Counterbalance Valve

Cross Section Of Counterbalance Valve (Neutral Position)

(1) Counterbalance valve. (2) Check valve. (3) Spring. (4) Passage (parking brake). (5) Counterbalance spool. (6)
Spring. (7) Check valve. (8) Orifice. (9) Port. (10) Port. (11) Cover (motor).

A counterbalance valve is installed in travel motor cover (11) and functions to prevent troubles such
as shock at travel stop, overrunning during traveling down a grade and/or cavitation. The valve also
functions to send part of pump oil to the parking brake for brake release just before the start of
machine movement.

Travel

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 107 of 152

Cross Section Of Counterbalance Valve (Travel Position)

(2) Check valve. (3) Spring. (4) Passage (parking brake). (5) Counterbalance spool. (8) Orifice. (9) Port. (10) Port. (11)
Cover (motor). (12) Passage. (13) Spool chamber. (14) Passage. (15) Passage. (16) Passage. (17) Motor rotary group.

The pump oil delivered to port (9) forces check valve (2) to open and goes through passage (16) to
motor rotary group (17). Also, part of pump oil through port (9) goes through orifice (8) of
counterbalance spool (5) and passage (15), and enters spool chamber (13). This moves spool (5) to
the left to open passage (12). Passage (12) allows the motor return oil from passage (12) to go out
through port (10) and back to the tank. As a result, the motor starts to turn.

As spool (5) moves to the left, passage (4) also is opened which allows part of pump oil through port
(9) to go to the parking brake. The brake is released and the motor is free to turn.

If the pump oil is sent to the counterbalance valve through port (10), spool (5) moves to the right and
the motor turns in the reverse direction in the same operating principle as described above.

Travel Stop

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 108 of 152

Counterbalance Valve Operation (Travel Stop Position)

(3) Counterbalance spool. (6) Spring. (8) Orifice. (9) Port. (10) Port. (12) Passage. (13) Spool chamber. (14) Passage.
(15) Passage. (17) Motor rotary group.

When oil flow to port (9) is blocked, there is a decrease in oil pressure in spool chamber (13).
Counterbalance valve (5) is then moved to the right (to the Neutral position) by the force of spring
(6). This causes the oil in spool chamber (13) to go through passage (15) and out through port (9).
At this time, since orifice (8) and passage (15) give a restriction to the flow, there is an appropriate
increase in pressure in spool chamber (13). This slows down the return movement of spool (5)
which in turn closes passage (12) slowly.

When there is no oil supplied to port (9), the machine is still in rotation because of the machine's
mass in motion. The motor return oil from rotary group (17) goes through passage (14) and is then
restricted at passage (12) which slows down the motor rotation. Eventually, spool (5) is returned to
the neutral position to close passage (12). This blocks the motor return oil flow to stop the motor. As
a results, the motor can stop smoothly without causing shock loads to the machine.

When oil flow through port (10) is blocked, spool (5) moves to the left and the motor can stop
slowly in the same operating principle as described above.

Travel (Down Grade)

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 109 of 152

Counterbalance Valve Operation (Traveling Down Position)

(5) Counterbalance spool. (6) Spring. (8) Orifice. (9) Port. (12) Passage. (13) Spool chamber. (14) Passage. (15)
Passage. (16) Passage. (17) Motor rotary group.

When the machine moves down a slope, the mass of the machine can cause the travel motors to
overspeed. The pumps can not maintain the supply of oil through port (9) to the motors. This could
cause cavitation in the motor. This causes a decrease in pressure (negative pressure) at port (9), in
spool chamber (13) and passage (16).

As pressure decreases in chamber (13), spool (5) is moved to the right by the force of spring (6) to
close passage (12). Flow of the return oil from rotary group (17) is restricted at passage (12). This
increases the pressure of the return oil which causes the motor to get in the braking condition. When
this condition happens, there is an increase in pressure of the pump oil sent to port (9). The oil then
goes through orifice (8) and passage (15), and into spool chamber (13). This moves counterbalance
spool (5) to the left against the force of spring (6) which partially opens passage (12). The pressure
of return oil in passage (14) decreases because of decreased resistance to flow. The motor can now
overspeed again. To prevent this, passage (12) is again restricted.

The above operation continues to repeat to allow the motor to operate according to the amount of oil
supplied from the pump. This eliminates cavitation.

Oil Makeup Operation

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 110 of 152

Oil Makeup Circuit

(1) Left travel motor. (2) Motor rotary group. (3) Passage. (4) Check valve. (5) Port. (6) Line. (7) Line. (8) Rotary joint.
(9) Port. (10) Passage. (11) Left travel control valve. (12) Passage. (13) Return passage.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 111 of 152

Cross Section Of Left Travel Control Valve

(9) Port. (10) Passage. (12) Passage. (13) Return passage.

Oil makeup operation is given with respect to left travel. Operation is the same for right travel.

If the left travel control lever is returned to the Neutral position to stop left travel, supply of pump
oil to motor (1) is blocked at passage (12).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 112 of 152

Makeup Valve (Check Valve) Operation

(2) Motor rotary group. (3) Passage. (4) Check valve. (5) Port.

Even when there is no pump oil supplied to the travel motor, the motor continues to rotate because
of the mass of the machine. This develops a negative pressure at passage (3) of motor rotary group
(2) which opens check valve (4).

With valve (11) in neutral, return oil from passage (13) flows to passage (10). The return oil then
goes through port (9), line (6), rotary joint (8) and line (7) to port (5). Then the oil passes through
opened check valve (4), passage (3), and into rotary group (2) as makeup oil. This makeup oil circuit
eliminates the possibility of cavitation occurring in the motor.

Operation of the right travel motor for prevention of cavitation is the same as that described above
for left travel motor.

Parking Brake

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 113 of 152

Cross Section Of Travel Motor (Partial) (Parking Brake Section)

(1) Orifice. (2) Shaft (motor). (3) Brake pilot valve. (4) Passage. (5) Barrel. (6) Friction plate. (7) Steel plate. (8) Piston
chamber. (9) Counterbalance spool. (10) Passage. (11) Passage. (12) Spring. (13) Housing (motor). (14) Cover (motor).
(15) Brake piston.

In the parking brake part of the travel motor, steel plates (7) are splined to housing (13). Friction
plates (6) are splined to barrel (5).

When there is no pump oil supplied to the travel motor, the motor stops rotation. Then the parking
brake mechanically engages. If the motor gets the oil supply from the pump, the brake is released
and then the motor starts to rotate.

With no pump oil to the motor, brake piston (15) is pushed to the left by the force of spring (12). At
this time, piston chamber (8) is open to case drain of the motor through passages (11) and (10) and
orifice (1). Along with the movement of brake piston (15), steel plates (7) and friction plates (6) are
held together against housing (13). This stops rotation of barrel (5) and shaft (2). Now the machine
parking brake mechanically engages.

Orifice (1) in brake pilot valve (3) restricts the return oil from piston chamber (8). This delays
engagement of the parking brake. If the return oil was not restricted by orifice (1), the parking brake
would start to engage before travel of the machine is stopped. This would result in earlier wear
and/or damage.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 114 of 152

Cross Section Of Brake Pilot Valve (Brake OFF Position)

(1) Orifice. (3) Brake pilot valve. (4) Passage. (9) Counterbalance spool. (14) Cover (motor). (16) Poppet. (17) Spring.
(18) Retainer.

When pump oil is supplied to the motor, counterbalance spool (9) shifts which allows oil flow to
passage (4). The oil in passage (4) opens poppet (16) of brake pilot valve (3) and closes orifice (1).
The oil then goes through passage (11) and into piston chamber (8). This moves brake piston (15)
away from plates (7) and (6) against the force of spring (12). As a result, the force that holds steel
plates (7) and friction plates (6) together is released. Now barrel (5) and shaft (2) are free to turn.

Rotary Joint

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 115 of 152

Rotary Joint
(1) Cover. (2) Drain port. (3) Seal. (4) Port. (5) Port. (6) Upper housing. (7) Port. (8) Port. (9) Lower housing. (10)
Flange. (11) Drain port. (12) Port. (13) Port. (14) Port. (15) Port. (16) Front direction. (17) Rotary joint.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 116 of 152

The rotary joint accomplishes two functions. One functioin is to supply pump oil from the upper
structure (which swings) to the travel motors of the lower structure (which does not swing). It also
functions to provide a means for oil from the motors to return to the hydraulic tank.

Upper housing (6) is bolted to the upper structure. Lower housing (9) is bolted to the lower structure
through flange (10). The ports of upper housing (6) are open to the ports of lower housing (9)
through passages in lower housing (9).

Seals (3) are provided between the sliding surfaces of lower and upper housings to prevent oil
leakage between the passages.

Travel Drive

Cross Section Of Travel Drive

(1) Flange. (2) Housing. (3) Cover. (4) Gear. (5) Shaft (motor). (6) Gear. (7) Crankshaft. (8) Gear. (9) Pin. (10) Gear.
(11) Travel motor.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 117 of 152

Travel Drive
(12) Sprocket wheel. (13) Travel drive.

Travel drive (13) and travel motor (11) are combined to make one assembly.

Rotation of the motor is transmitted to the travel drive through shaft (5) and gear (4). The travel
drive reduces the speed of rotation and increases its torque. Travel drive housing (2) has flange (1)
where sprocket wheel (12) is bolted. As a result, the torque increased by the travel drive is
transmitted to sprocket wheel (12) through housing (2) which in turn causes the track to rotate.

First Stage Reduction Section

(4) Gear. (5) Shaft (motor). (6) Gear. (7) Crankshaft.

In the first stage reduction, when gear (4) is rotated clockwise by the motor shaft, three gears (6)
which engage with gear (4) rotate counterclockwise. Also, each crankshaft (7) which is splined to
gears (6) rotates counterclockwise.

Gear (4) has 15 teeth while each gear (6) has 24 teeth. The speed is reduced here in the ratio of 15 to
24.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 118 of 152

Movement Of Gears (8) And (10)

(6) Gear. (7) Crankshaft. (8) Gear. (10) Gear. (14) Eccentric section. (15) Eccentric section.

In the second stage reduction, with rotation of crankshaft (7), sections (14) and (15) turn to transmit
movement to gears (10) and (8) respectively.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 119 of 152

Second Stage Reduction Section (Reduction By Eccentric Movements)

(2) Housing. (9) Pin. (10) Gear. (16) Pin (first one). (17) Pin (last one). P : Pitch of pin (9).

Housing (2) has 36 pins (9) which are in rolling contact with 35 teeth of each gear (8) and (10).
Movement of gears (8) and (10) caused by crankshafts (7) give rotation to housing (2) through pins
(9).

Description is given with respect to clockwise rotation of crankshafts (7) as shown in above
illustration.

Just before crankshafts (7) start rotation, gear (10) takes position (1) where a full engagement of
uppermost pin (16) and gear (10) is made. When crankshafts (7) turn 180°, gear (10) takes position
(2) where a full engagement of lower most pin and gear (10) is made. At this position, pin (16) turns
clockwise by half a pitch of pin. When crankshafts (7) turn a full turn, a full engagement (3) is made
between gear (10) and another uppermost pin (17) which is located next to pin (16). For each
rotation of crankshafts (7), housing (2) advances by one pin (=36-35). The ratio is 1/36.

For each rotation of motor shaft (5), gears (10) and (8) turn 15/24 of a turn. Thus, the overall
reduction ratio is;

15/24 × 1/36 = 1/57.6

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 120 of 152

The motor shaft must turn 57.6 turns for the housing to make one full turn.

Loading Operation (Mode Switch To Dump /

Loading)
Introduction

Combined Operations Of Boom RAISE, Stick OUT And Swing RIGHT

Combined Operations Of Boom LOWER, Stick OUT and Swing LEFT

With the bucket loaded (or filled), it is moved to the dump location by simultaneous (at the same
time) operation of boom RAISE, stick OUT and swing. After the bucket is unloaded at the dump
location, it is moved to the original excavating position by simultaneous operations of boom
LOWER, stick OUT and swing. This is one cycle of the loading operation.

Depending on whether the boom is raised or lowered, the flow rate of oil from both pumps to the
implement and swing motors varies.

For loading operations, work mode switch (1) should be placed in Dump/Loading Mode (2).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 121 of 152

Right Console
(1) Work mode switch.

Work Mode Switch

(1) Work mode switch. (2) Dump/loading mode.

Combined Loading Operations

Boom RAISE, Stick OUT And Swing

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 122 of 152

Schematic (Partial) (Boom RAISE, Stick OUT And Swing)

(1) Line. (2) Line. (3) Line. (4) Passage. (5) Passage. (6) Passage. (7) Parallel feeder passage. (8) Boom control valve.
(9) Check valve. (10) Boom control valve. (11) Stick control valve. (12) passage. (13) Check valve. (14) Logic valve.
(15) Swing control valve. (16) Passage. (17) Passage. (18) Parallel feeder passage. (19) Selector valve. (20) Check valve.
(21) Front pump. (22) Rear pump. (23) Pilot pump.

In a loading operation involving boom RAISE, stick OUT and swing, the pumps are used as follows:

1. The large load placed on the boom cylinders results in high pressure, small flow from the
pump. For fast movement of the boom to a high position, the boom cylinder gets all of the oil
from front pump (21) and part of the oil from rear pump (22).
2. To get the correct swing and stick movement relative to boom movement, the stick and
swing circuits share oil from rear pump (22). If swing movement is too fast, the bucket would
reach the side of the dump unit before the boom is raised high enough to clear the side.

In this part of a loading operation, pilot oil operates boom valve (8), boom valve (10), swing valve
(15) and stick valve (11).

With boom raised, selector valve (19) is closed and logic valve (14) is open. (More details will be
given later.)

The oil from the front pump goes through parallel feeder passage (18) and passage (16) to boom
control valve (8). The oil then goes through lines (3) and (2) to the head end of the boom cylinder.
Because selector valve (19) is closed, no front pump oil in parallel feeder passage (18) goes through
check valve (20), passages (17) and (12) to stick control valve (11). As a result, all the front pump
oil goes to boom control valve (8) through parallel feeder passage (18).

The rear pump oil flows through parallel feeder passage (7) and then separates into the following
three oil flows.

1. One path goes through passage (6) to swing control valve (15). The oil is then supplied to
the swing motor.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 123 of 152

2. Another path goes through passage (5), logic valve (14), check valve (13) and passage (12)
to stick control valve (11). The oil is then supplied to the rod end of the stick cylinder.
3. The third path goes through passage (4), boom control valve (10) and check valve (9) to
line (1). The oil then combines with the front pump oil in line (2) and goes to the head end of
the boom cylinder.

In this type of loading operation, most of the work is done through the boom RAISE movement to
clear the excavation after digging. Little is done by stick and swing circuits.

Most of the rear pump oil is supplied to the boom cylinder through boom control valve (10). This
can move the boom up at a faster speed.

Immediately after the bucket clears the excavation, stick and swing operations combine with the
boom RAISE operation. The load on the front pump (when the boom is raised) remains larger than
for the stick and swing circuits. Because the pressure in line (1) is higher than that in parallel feeder
passage (7), check valve (9) is closed most of the time. The possibility of rear pump oil flow through
parallel feeder passage (7) to line (1) side is small. Most of rear pump oil will be supplied to the
swing control valve and stick control valve. As a result, swing and stick operation is not affected by
boom operation.

Boom LOWER, Stick OUT And Swing

Schematic (Partial) (Boom LOWER, Stick OUT And Left Swing)

(4) Passage. (5) Passage. (6) Passage. (7) Parallel feeder passage. (8) Boom control valve. (10) Boom control valve. (11)
Stick control valve. (12) Passage. (14) Logic valve. (15) Swing control valve. (16) Passage. (17) Passage. (18) Parallel
feeder passage. (19) Selector valve. (20) Check valve. (21) Front pump. (22) Rear pump. (23) Pilot pump. (24) Passage.

In a loading operation involving boom LOWER, stick OUT and left swing, the pumps are used as
follows:

1. During boom LOWER, the smaller load on the boom results in decreased pressure and
increased flow from the front pump. This moves the boom down at a faster speed. To get the
correct speed for boom LOWER and stick OUT, front pump (21) sends most of its oil to the
boom cylinder and the remainder to the stick cylinder.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 124 of 152

2. To decrease the cycle time of loading operation, the swing speed is increased in proportion
to the faster boom and stick movements. For this purpose, the swing circuit gets all of the oil
from rear pump (22).

In this type of loading operation, pilot oil operates boom control valve (8), swing control valve (15)
and stick control valve (11). At this time, selector valve (19) is open and logic valve (14) and boom
control valve (10) are closed.

The front pump oil flows through parallel feeder passage (18) and then separates into following two
oil flows.

1. One oil flow goes through passage (16) and into boom control valve (8). The oil is then
supplied to the rod end of the boom cylinder.
2. The other oil flow goes through selector valve (19), check valve (20), passages (17) and
(12), and to stick control valve (11). The oil is then supplied to the rod end of the stick
cylinder.

Because the oil flow through selector valve (19) is restricted by passage (24), most of the front pump
oil goes through passage (16) to the boom cylinder. The remainder of the front pump oil goes
through selector valve (19) to the stick cylinder.

The rear pump sends all of its oil to swing control valve (15) through parallel feeder passage (7) and
passage (6). The oil is then supplied to the swing motor. Because logic valve (14) and boom control
valve (10) are closed, as described before, there is no oil supplied to the stick cylinder and boom
cylinder through passages (5) and (4), respectively.

Selector Valve And Logic Valve

Boom Raise

Schematic (Partial) (Selector Valve In Closed Position, Logic Valve In Open Position)
(1) Stick control valve. (2) Passage. (3) Straight travel valve. (4) Parallel feeder passage. (5) Boom control valve. (6)

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 125 of 152

Stick control valve. (7) Logic valve. (8) Passage. (9) Passage. (10) Check valve. (11) Orifice. (12) Line. (13) Passage.
(14) Check valve. (15) Pilot passage. (16) Check valve. (17) Passage. (18) Passage. (19) Port. (20) Parallel feeder
passage. (21) Passage. (22) Pilot passage. (23) Orifice. (24) Solenoid valve II. (25) Line. (26) Pilot passage. (27)
Passage. (28) Selector valve. (29) Line. (30) Pilot manifold. (31) Drain line. (32) Passage. (33) Passage. (34) Line. (35)
Front pump. (36) Rear pump. (37) Drain line. (38) Suction line. (43) Passage.

When boom control valve (5) operates to the boom RAISE position, there is an open connection
between passages (18) and (8). Passage (8) is connected through drain line (34), passage (33) in pilot
oil manifold (30) and drain line (37) to pump suction line (38). As a result, the pressure in passage
(18) becomes low.

Selector Valve

Control Valve Compartment

(6) Stick control valve. (28) Selector valve.

Cross Section Of Selector Valve (Selector Valve In Closed Position)

(6) Stick control valve. (10) Check valve. (11) Orifice. (20) Parallel feeder passage. (22) Pilot passage. (23) Orifice. (26)

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 126 of 152

Pilot passage. (27) Passage. (28) Selector valve. (29) Drain line. (39) Spool. (40) Spring. (41) Spool chamber. (42)
Valve block. (43) Passage. (44) Passage.

Selector valve (28) is located in valve block (42) which also contains stick control valve (6).

The front pump oil from parallel feeder passage (20) goes through passages (43) and (44), and
orifice (23) to pilot passage (22). The oil then opens check valve (10) to allow oil flow through
orifice (11), lines (29) and (25), solenoid valve II (24), passage (32) and line (31) to passage (18).
Because the pressure in passage (18) is low, the pressure in pilot passage (22) becomes low.

Part of the front pump oil from passage (20) goes through passage (43) and pilot passage (26) to
chamber (41). Because of orifice (23), pressure in passage (22) is low and pressure in passage (26) is
high. As a result, spool (39) shifts to the right. This closes passage (27) to allow all of the front
pump oil in parallel feeder passage (20) to go through passage (21) to boom control valve (5). The
oil is then supplied to the head end of the boom cylinder.

Logic Valve

Control Valve Compartment

(7) Logic valve.

Cross Section Of Logic Valve (Logic Valve In Open Position)

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 127 of 152

(2) Passage. (3) Straight travel valve. (4) Parallel feeder passage. (7) Logic valve. (12) Line. (13) Passage. (14) Check
valve. (15) Pilot passage. (16) Check valve. (17) Passage. (19) Port. (45) Valve block.

Logic valve (7) is located in travel control valve block (45) which also contains straight travel valve
(3) and check valves.

The oil in pilot passage (15) of logic valve (7) goes through check valve (16) and line (12) to line
(25). The oil then vents through solenoid valve II (24), passage (32), line (31) and passage (18) to
pump suction. This makes the pressure in pilot passage (15) low.

Rear pump oil flows through port (19), passage (17), parallel feeder passage (4) and passage (2) to
valve (7). When the pressure in pilot passage (15) becomes low enough to open logic valve (7), the
rear pump oil in passage (2) goes through logic valve (7), check valve (14) and passage (13) to stick
control valve (1). The oil is then supplied to the rod end of the stick cylinder.

Boom Lower

Schematic (Partial) (Selector Valve In Open Position, Logic Valve In Closed Position)
(1) Stick control valve. (2) Passage. (3) Straight travel valve. (4) Parallel feeder passage. (5) Boom control valve. (6)
Stick control valve. (7) Logic valve. (8) Passage. (9) Passage. (10) Check valve. (11) Orifice. (12) Line. (13) Passage.
(14) Check valve. (15) Pilot passage. (16) Check valve. (18) Passage. (20) Parallel feeder passage. (21) Passage. (22)
Pilot passage. (23) Orifice. (24) Solenoid valve II. (25) Line. (26) Pilot passage. (27) Passage. (28) Selector valve. (29)
Line. (30) Pilot oil manifold. (31) Line. (32) Passage. (35) Front pump. (36) Rear pump. (43) Passage. (45) Check valve.

When boom control valve (5) is moved to the boom LOWER position, the path between passages
(18) and (8) is closed.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 128 of 152

Cross Section Of Selector Valve (Selector Valve In Open Position)

(3) Straight travel valve. (9) Passage. (10) Check valve. (11) Orifice. (20) Parallel feeder passage. (22) Pilot passage.
(23) Orifice. (26) Pilot passage. (27) Passage. (29) Line. (39) Spool. (40) Spring. (41) Spool chamber. (43) Passage. (44)
Passage. (45) Check valve.

Front pump oil from parallel feeder passage (20) goes through passage (43) and then separates into
two pilot oil flows. One oil flow goes through pilot passage (26) and into spool chamber (41). The
other oil flow goes through passage (44) and orifice (23) to pilot passage (22).

Oil flow from pilot passage (22) through solenoid valve II (24) is blocked at passage (18). Also,
flow through line (12) is blocked by check valve (16). As a result of blocked oil flow in passage (26)
and passage (22), their oil pressures are equal. Because the pressure acting on both sides of spool
(39) is equal, spool (39) is moved to the left by the force of spring (40) to open passage (27).

As passage (27) is opened, the oil in parallel feeder passage (20) goes through passage (27) and
check valve (45) to passage (9). The oil then goes through passage (13) to stick control valve (1) and
is supplied to the stick cylinder.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 129 of 152

Cross Section Of Logic Valve (Logic Valve In Closed Position)

(2) Passage. (3) Straight travel valve. (4) Parallel feeder passage. (7) Check valve. (12) Line. (13) Passage. (14) Check
valve. (15) Pilot passage. (16) Check valve.

Because oil flow through line (12) is blocked, check valve (16) is kept closed. The force of the
spring in valve (7) closes the valve. This blocks the flow of rear pump oil through parallel feeder
passage (4) to stick control valve (1).

Leveling Operation (Mode Switch To Inching)

Introduction
The purpose of a leveling operation is to level a ground surface with high accuracy using the
combined movement of the boom and stick. During a leveling operation, the boom and stick make
fine movements to keep the tip of the bucket against the ground surface.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 130 of 152

Leveling (Movement Of Boom And Stick)

For leveling operation, the movement of stick IN and boom RAISE is combined. In this operation,
boom and stick circuits get oil from separate pumps. Operation of the boom and stick cylinders does
not affect each other. Operation of power and mode switches provides a better inching operation of
the boom and stick.

Right Console
(1) Switch (work mode). (2) Switch (power mode).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 131 of 152

Switch Controls
(1) Switch (work mode). (2) Switch (power mode). (3) Switch position (inching mode). (4) Switch position (Mode I).

Since leveling operations are slow speed work "power" mode switch (2) is turned to Mode I position
(4) for light work. Also, "work" mode switch (1) is turned to inching Mode position (3) to keep the
boom and stick operating circuits separated at a reduced rate of flow.

Leveling Circuit

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 132 of 152

Schematic (Partial)
(1) Stick cylinder. (2) Boom cylinder. (3) Return line. (4) Return passage. (5) Center bypass passage. (6) Slot. (7)
Bypass passage. (8) Boom control valve. (9) Stick control valve. (10) Pilot line. (11) Passage. (12) Slot. (13) Center
bypass passage. (14) Passage. (15) Check valve. (16) Line. (17) Pilot passage. (18) Boom control valve. (19) Bypass
passage. (20) Stick control valve. (21) Pilot passage. (22) Parallel feeder passage. (23) Pilot passage. (24) Return
passage. (25) Selector valve. (26) Port. (27) Pilot control valve (stick). (28) Return line. (29) Solenoid valve I. (30) Line.
(31) Passage. (32) Passage. (33) Line. (34) Shuttle valve. (35) Passage. (36) Pilot oil manifold. (37) Drain line. (38)
Front pump. (39) Rear pump. (40) Pilot pump. (41) Hydraulic tank.

When the boom and stick control levers are moved slowly to the rear, pilot oil goes through
passages (17), (21) and (23) to boom valve (18), stick valve (20), and boom valve (8) respectively.

Since work mode switch (1) is set at inching mode position (3), solenoid valve I (29) energizes to
block pilot oil to pilot line (10).

When pilot oil is supplied to the above valves, each valve operates as follows.

1. Since pilot passage (17) is common with pilot passage (23), boom pilot oil is the same in
both. However, the force of the return spring for boom control valve (18) is greater than the
return spring for boom control valve (8). Since the low pilot pressure used for boom inching
operation cannot operate valve (18), valve (18) remains open. This allows part of the rear
pump oil to drain from center bypass passage (13) to hydraulic tank (41). This results in fine
control of the stick.
2. With solenoid valve I (29) energized, pilot oil flow from stick pilot control valve (27)
through line (30) is blocked at port (26). This blocks pilot oil to valve (9). The oil in pilot line
(10) from stick control valve (9) goes to drain through shuttle valve (34) and return line (28)

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 133 of 152

to the return port of stick pilot control valve (27). Because stick control valve (9) is in the
open position, part of front pump oil is drained to the tank from center bypass passage (5).
This allows fine control of the boom.
3. The spool of boom control valve (8) is partially moved. This allows part of the front pump
oil to drain from center bypass passage (5) to bypass passage (7) in the boom control valve.
As a result, the amount of front pump oil that is supplied from parallel feeder passage (22)
through slot (6) to boom cylinders (2) is decreased for better inching operation of boom
cylinder.
4. The spool of stick control valve (20) is also partially moved. In the same manner as
described above, this allows part of rear pump oil to drain from center bypass passage (13) to
bypass passage (19) of the stick control valve. The amount of rear pump oil supplied from
center bypass passage (13) through slot (12) to stick cylinder (1) is decreased for better
inching operation of the stick cylinder.
5. The pressure of oil in center bypass passage (5) which is connected to the tank does not
increase high enough to open check valve (15) in passage (14). As a result, there is no front
pump oil flow through passage (16) to the stick circuit.
6. With the boom raised, selector valve (25) is in the CLOSED position, as described before in
the "Loading Operation" section. This allows all of front pump oil in parallel feeder passage
(22) to go to boom cylinder (2).

Items 1, 2, 3 and 4 described above provide sure inching operations of the boom and stick. Items 5
and 6 describe how the boom and stick circuits are separated. As a result, movement of one cylinder
does not affect the movement of the other during inching operation of the boom and stick.

During leveling operation, the operating speed can be increased by slowly pulling the stick control
lever of the pilot control valve further. However, when the boom control lever is moved beyond mid
position, there is an increase in pilot pressure in passage (17). This closes the center bypass passage
of boom control valve (18). As a result, inching operation of the stick becomes difficult.

Metering Operation

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 134 of 152

Cross Section Of Stick Control Valve (Partial)

(11) Passage. (12) Metering slot. (13) Center bypass passage. (19) Bypass passage. (42) Spool.

The spools of boom control valve (8) and stick control valve (20) have metering slots. Oil from the
rear pump is metered through slot (12) to the head end of stick cylinder (1). Oil from front pump is
metered through slot (6) to the head end of boom cylinder (2).

When the stick control lever is moved for stick IN leveling, spool (42) is slightly moved to the left
and the rear pump sends two oil flows.

In one path, oil goes through center bypass passage (13), bypass passage (19) and past boom control
valve (18) to return passage (4).

The other path goes through center bypass passage (13) and is metered through slot (12) to the head
end of stick cylinder (1).

If the opening of slot (12) becomes smaller, the amount of oil through bypass passage (19) will
increase. In turn, the amount of oil through slot (12) to the stick cylinder will decrease for better
inching operation of the stick cylinder.

Slot (6) of boom control valve (8) operates the same as that described above for slot (12).

Solenoid Valve I

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 135 of 152

Cross Section Of Solenoid Valve I (Solenoid Energized)

(26) Port. (29) Solenoid valve I. (31) Passage. (32) Passage. (43) Passage. (44) Spool.

Pump Compartment
(29) Solenoid valve I. (36) Pilot oil manifold.

If the stick control lever is slowly moved back, pilot oil is routed from stick pilot control valve (27)
to port (26) of solenoid valve I (29).

With work mode switch (1) set in Inching Mode (3) position, solenoid valve I (29) is energized and
spool (44) is forced to the left. Pilot oil is blocked from going through passage (43) to stick control
valve (9). Instead, oil coming in through passage (31) goes through the passage inside spool (44) and
out through passage (32). This oil then goes to the pump suction line through drain line (37).

The oil in pilot line (10) from stick control valve (9) returns through shuttle valve (34) and stick
pilot control valve (27) to the pump suction line. As a result, stick control valve (9) is opened and
center bypass oil flow is allowed to return to tank (41) through return passage (24) and return line
(3).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 136 of 152

Ditch (Trench) Excavation Operation (Mode

Switch To Side Wall Crowding)
Introduction

Ditch (Trench) Excavation (Illustration Of Applied Swing Force)

When excavating a trench, its cross section should be exactly rectangular. However, because of the
force of the trench wall, the bucket wants to move away from the wall of the trench.

To get a straight (vertical) wall, it is necessary that an additional side force be used to hold the
bucket against the side wall. The operator does this by applying partial swing in the direction of the
wall.

Right Console
(1) Switch (work mode). (2) Switch (power mode).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 137 of 152

Work Mode Switch

(1) Switch (work mode). (2) Switch (power mode). (3) Switch (side wall crowding).

When the bucket needs an additional side force from the swing circuit, set work mode switch (1) to
position (3). Depending on work conditions, power mode switch (2) may be set to any of the mod I,
II and III.

Crowding Operations (Solenoid Valve II Energized)

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 138 of 152

Hydraulic Schematic (Partial) (Side Wall Crowding Operation)

(4) Pilot passage. (5) Return line. (6) Main control valves. (7) Boom control valve. (8) Bucket control valve. (9) Pilot
passage. (10) Boom control valve. (11) Stick control valve. (12) Swing control valve. (13) Stick control valve. (14)
Parallel feeder passage. (15) Passage. (16) Passage. (17) Passage. (18) Passage. (19) Logic valve. (20) Pilot passage.
(21) Pilot passage. (22) Parallel feeder passage. (23) Pilot passage. (24) Pilot passage. (25) Selector valve. (26) Pilot
line. (27) Solenoid valve II. (28) Pilot line. (29) Pilot line. (30) Port. (31) Pilot oil manifold. (32) Front pump. (33) Rear
pump. (34) Pilot pump

A side wall crowding operation is done by combined operation of the control levers for swing, boom
(inching), stick and bucket.

When the control levers are operated, pilot pressure is sent to passages (20), (4), (21), (23), (24) and
(9) to operate control valves for swing (12), boom (7), stick (11) and (13) and bucket (8),
respectively.

Pilot passages (20) and (23) get the same boom pilot pressure. However, the return spring for boom
control valve (10) is stronger than that for valve (7). As a result, valve (10) is not operated by the
low pilot pressure used for the boom inching operation.

With work mode switch (1) in position (3) for side wall crowding operation, solenoid valve II (27) is
energized to close port (30). This allows no oil flow from pilot lines (26), (28) and (29). In turn,
logic valve (19) remains closed and selector valve (25) remains open.

Operations of the valves, as described above, allow the circuit oil to flow as follows during a side
wall crowding operation.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 139 of 152

1. All of the oil from rear pump (33) flows through passage (16), parallel feeder passage (14)
and swing control valve (12) to the swing motor. The swing motor uses its torque only for
holding the bucket against the side wall and does not rotate.

All of the oil supplied to the swing motor is vented through the relief valve of the motor to
develop relief pressure. This increases the motor torque to securely hold the bucket against the
side wall.

2. The oil from front pump (32) flows through passage (15), parallel feeder passage (22) to
control valves for boom (7) and bucket (8). Also, because selector valve (25) is open, there is
front pump oil flow through passages (18) and (17) to stick control valve (11).

The rate at which the boom and bucket are moved during excavation of a trench is slow. As a result,
only part of the front pump oil is used to operate the boom and bucket cylinders. The remainder of
the front pump oil is supplied to the stick cylinder to increase the operating speed of the stick.

Solenoid Valve II

Top View Of Pilot Oil Manifold

(27) Solenoid valve II. (31) Pilot oil manifold.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 140 of 152

Cross Section Of Solenoid Valve II (Solenoid Energized)

(27) Solenoid valve II. (30) Port. (35) Passage. (36) Port. (37) Spool. (38) Drain port. (39) Passage. (40) Passage.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 141 of 152

Hydraulic Schematic (Pilot Circuit)

(7) Boom control valve. (11) Stick control valve. (14) Parallel feeder passage. (19) Logic valve. (22) Parallel feeder
passage. (25) Selector valve. (26) Pilot line. (27) Solenoid valve II. (28) Pilot line. (29) Pilot line. (30) Port. (36) Port.
(38) Drain port. (41) Pilot passage.

When work mode switch (1) is set to position (3) for a side wall crowding operation, solenoid valve
II (27) is energized. Spool (37) moves down. Passages (35) and (39) open, and passage (40) is
closed.

This allows no oil flow through pilot lines (26), (28) and (29). As a result, logic valve (19) is closed
which in turn allows no oil flow from parallel feeder passage (14) to stick control valve (11).

Also, selector valve (25) remains open because the pilot pressure in pilot passage (29) is equal to
that in pilot passage (41).

Straight Travel Control

Introduction

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 142 of 152

Control Valve Compartment (Viewed From Rear of Machine)

(1) Boom. (2) Stick. (3) Swing. (4) Left travel. (5) Right travel. (6) Boom. (7) Bucket. (8) Stick. (9) Line (from front
pump outlet). (10) Straight travel valve. (11) Line (from rear pump outlet).

Hydraulic Schematic (Partial) (Only Right and Left Travel Activated)

(4) Left travel control valve. (5) Right travel control valve. (9) Line (from rear pump outlet). (10) Straight travel valve.
(11) Line (from rear pump outlet). (12) Main control valves. (13) Front pump. (14) Rear pump. (15) Pilot pump.

If the upper structure or implements are operated while the machine is traveling, straight travel valve
(10) makes sure that the machine travels straight. It also allows better control for operations such as
pipe laying or placement of timbers.

When the machine travels with no swing or implement operation, oil from front pump (13) drives
the right travel motor and oil from rear pump (14) drives the left travel motor. Since both these
circuits are separated, the machine continues to travel straight, unless a difference in travel
resistance occurs between the right and left tracks.

However, if a swing or implement operation was used during travel without the straight travel
system, the amount of oil supplied from front pump (13) and rear pump (14) would differ. This

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 143 of 152

would affect the oil supplied to the right and left travel motors and cause the machine not to travel in
a straight line.

The straight travel system makes sure that the machine travels straight when circuits other than the
travel circuits are simultaneously operated while the machine is traveling. When straight travel valve
(10) is actuated by pilot pressure, the following occurs.

1. Front pump (13) supplies oil not only to the right travel circuit but also to the left travel
circuit to drive both motors in parallel.
2. The swing and implement circuits get their supply of pressure oil from rear pump (14).
However, when the machine is traveling, the swing and implement circuits do not require a
large amount of flow. They are operated at speeds low enough to keep the machine stable.
Therefore, the remainder of the pressure oil is divided between the right and left travel
circuits.

Implement And Travel Operation

Hydraulic Schematic (Partial) (Bucket and Travel Activated)

(1) Return line. (2) Parallel feeder passage. (3) Main control valves. (4) Stick control valve. (5) Swing control valve. (6)
Left travel control valve. (7) Passage. (8) Center bypass passage. (9) Right travel control valve. (10) Boom control
valve. (11) Bucket control valve. (12) Passage. (13) Passage. (14) Passage. (15) Center bypass passage. (16) Passage.
(17) Passage. (18) Passage. (19) Passage. (20) Passage. (21) Straight travel valve. (22) Pilot passage. (23) Pilot passage.
(24) Pilot passage. (25) Pilot passage. (26) Drain line. (27) Pilot passage. (28) Parallel feeder passage. (29) Line. (30)
Line. (31) Pilot oil manifold. (32) Front pump. (33) Rear pump. (34) Pilot pump.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 144 of 152

When the bucket control lever is activated during travel, there is pilot oil flow from the travel pilot
control valves through pilot passages (27) and (24) to left and right travel control valves (6) and (9),
respectively. For bucket operation, pilot oil flows from bucket pilot control valve through pilot
passage (25) to bucket control valve (11).

As the bucket control valve is operated, passage (20) is closed. There is an increase in pilot pressure
in passages (22) and (23). The increased pilot pressure operates straight travel valve (21). (The
hydraulic schematic above shows valve (21) shifted.)

Passage (19) connects in series all of the control valves for swing and implements. If any of these
valves is operated, the connection between passage (19) and passage (13), (14) or (18) is closed. As
a result, the pilot pressure in pilot passages (22) and (23) increases enough to operate valve (21).

As long as all of control levers for swing and implements are in the neutral position, pilot passage
(22) is connected to pump suction line through passage (19) and line (26). As a result, the pilot
pressure in passages (22) and (23) is not enough to operate valve (21).

When valve (21) is operated, oil from both pumps flows as follows so that the machine can travel
straight.

1. Oil from front pump (32) flows through line (30) to passage (17) in main control valves (3).
It then flows in two directions. One path goes through center bypass passage (8) to right travel
control valve (9).

The other path goes through passage (7), through valve (21), and through center bypass
passage (15) to left travel control valve (6). As a result, the right and left travel motors get
equal amount of oil from the front pump.

2. Oil from rear pump (33) flows through line (29) to passage (16) in main control valves (3).
It then flows in two directions. One path goes through parallel feeder passage (2). The other
path goes through passage (12) and valve (21) to parallel feeder passage (28). Then part of oil
in passage (28) goes to bucket control valve (11) to operate the bucket.

Straight Travel Valve

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 145 of 152

Cross Section Of Straight Travel Valve (Neutral Position)

(1) Passage. (2) Straight travel valve. (3) Parallel feeder passage. (4) Center bypass passage. (5) Spool chamber. (6)
Passage. (7) Parallel feeder passage. (8) Center bypass passage. (9) Port. (10) Spool. (11) Pilot passage. (12) Front
pump. (13) Rear pump.

When there is a travel operation only, pilot pressure in pilot passage (11) is low. The pressure in
spool chamber (5) also remains low so that spool (10) does not shift. Oil from both pumps flows as
follows.

1. Oil from front pump (12) goes to passage (6) in the main control valves. It then flows in
two directions. One path goes through center bypass passage (4) to the right travel control
valve. The other path goes through valve (2) and parallel feeder passage (3) and enters control
valves for boom and bucket.
2. Oil from rear pump (13) goes through port (9) to passage (1) in the main control valves. It
then flows in two directions.

One path goes through parallel feeder passage (7) and enters control valves for swing and stick. The
other path goes through valve (2) and center bypass passage (8) to the left travel control valve.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 146 of 152

Cross Section Of Straight Travel Valve (Activated Position)

(1) Passage. (2) Straight travel valve. (3) Parallel feeder passage. (4) Center bypass passage. (5) Spool chamber. (6)
Passage. (7) Parallel feeder passage. (8) Center bypass passage. (9) Port. (10) Spool. (11) Pilot passage. (12) Front
pump. (13) Rear pump. (14) Passage. (15) Passage. (16) Orifice. (17) Passage. (18) Check valve.

When travel and implement (or swing) operation occurs, pilot pressure in pilot passage (11)
increases. This in turn increases the pressure in spool chamber (5) enough to shift spool (10) to the
left. This opens passage (14) and closes passages (15) and (17). Then pump oil flows as follows:

1. The front pump oil goes to passage (6) and then flows in two directions. One path goes
through center bypass passage (4) to the right travel control valve. The other path goes
through valve (2) and center bypass passage (8) to the left travel control valve.
2. The rear pump oil goes through port (9) to passage (1) and then flows in two directions.
One path goes through parallel feeder passage (7) and enters control valves for swing and
stick. The other path goes through valve (2) and parallel feeder passage (3) to control valves
for boom and bucket.

Part of rear pump oil in passage (1) which is not used for swing and/or implement operation goes
through orifice (16) and check valve (18) in spool (10) to center bypass passage (8). It then
combines with the front pump oil to help drive both right and left travel motors.

Blade Operation
Introduction

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 147 of 152

Machine View
(1) Blade cylinder. (2) Blade.

Blade (2) is installed to the front of the undercarrage (idle wheel side). It is used for leveling work.

In addition to the standard equipment, the blade machine is equipped with the following
components.

Blade Pump

Pump Compartment
(3) Main pump. (4) Blade pump. (5) Pilot pump.

Blade pump (4) is a gear type pump directly connected to main pump (3). It supplies oil flow to
blade cylinder (1) to operate the blade. The maximum flow rate is approximately 29 liter/min. (7.7
gpm).

Blade Control Valve

Pump Compartment
(6) Blade control valve. (7) Pilot oil manifold. (8) Main relief valve (blade).

Blade control valve (6) controls the oil flow which is sent to the blade cylinder. Valve (6) has a main
relief valve (8) which limits the blade system pressure to 17200 kPa (2500 psi).

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 148 of 152

Blade Control Lever

Cab
(9) Blade control lever.

Blade control lever (9) is mechanically linked to the spool in blade control valve (6). By activating
lever (9), the operations of blade RAISE, LOWER and FLOAT (leveling operation only by blade
mass) can be done.

Blade Cylinder

Blade cylinder (1) extends/retracts for blade LOWER or RAISE. In addition, if it is held at any
cylinder position with the blade control valve in NEUTRAL, the blade can be used as an outrigger.

Blade Lower

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 149 of 152

Schematic (Partial) (Boom LOWER)

(1) Blade cylinders. (2) Rotary joint. (3) Line. (4) Main control valves. (5) Line. (6) Return line. (7) Line. (8) Hydraulic
tank. (9) Port. (10) Port. (11) Line. (12) Line. (13) Return passage. (14) Return passage. (15) Main relief valve. (16)
Blade pump. (17) Line relief valve. (18) Check valve. (19) Passage. (20) Passage. (21) Center bypass passage. (22)
Blade control valve.

Pump Compartment
(6) Return line. (7) Line. (11) Line. (12) Line. (15) Main relief valve. (17) Line relief valve. (22) Blade control valve.
(23) Spool.

Oil from blade pump (16) flows through line (12) to blade control valve (22). When the blade
control lever is pushed forward, spool (23) moves out. This allows oil flow from valve (22) to blade
cylinders (1) for blade LOWER.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 150 of 152

Cross Section Of Blade Control Valve (Blade LOWER)

(9) Port. (10) Port. (13) Return passage. (14) Return passage. (18) Check valve. (19) Passage. (20) Passage. (21) Center
bypass passage. (23) Spool. (24) Passage. (25) Sleeve. (26) Ball. (27) Passage. (28) Passage. A : RAISE position. B :
LOWER position.

As spool (23) moves to the right, balls (26) move together until they go into the large-diameter
section of sleeve (25). When this happens, movement of the blade control lever is blocked. This is
the blade LOWER position (B). When the blade control lever is further pushed forward into detent,
the blade is placed in the FLOAT position. The blade can lower onto the ground by its own mass
since there is no hydraulic control on it in this position.

Never use the FLOAT position for lowering the blade to the ground.

Also, as spool (23) moves to the right, passage (19) is closed. This blocks flow between center
bypass passage (21) and passage (19).

In turn, all of oil from center bypass passage (21) flows through passage (20), check valve (18),
passages (24) and (27), and out valve (22) through port (9). The oil then flows through line (7),
rotary joint (2) and line (3) to the head end of blade cylinder (1). This causes blade LOWER
operation.

Return oil from cylinder (1) flows through line (5), rotary joint (2) and line (11), and enters valve
(22) through port (10). The oil then flows through passage (28), return passage (13) and (14) and
return line (6) to hydraulic tank (8).

Blade Raise

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 151 of 152

When the blade control lever is pulled backward, spool (23) moves to the left. In the same operating
principle as that described for blade LOWER, valve (22) sends pump (16) oil to the rod end of
cylinder (1) for blade RAISE operation.

Blade Float

Cross Section Of Blade Control Valve (Blade FLOAT)

(9) Port. (10) Port. (13) Return passage. (14) Return passage. (19) Passage. (21) Center bypass passage. (23) Spool. (25)
Sleeve. (26) Ball. (27) Passage. (28) Passage. (29) Slot. C : FLOAT position.

Leveling operation on soft surface can be made with the blade in the FLOAT position (C). In this
position, no hydraulic oil is supplied to the blade cylinder and there is no hydraulic control on the
cylinder. In turn, the blade stays on the ground by its own mass.

The blade control lever is placed in the FLOAT position when it is pushed all the way forward into
detent.

In the FLOAT position, balls (26) are held in slot (29) and spool (23) remains in this position until
the blade control lever is pulled out of detent.

Open passage (19) allows oil flow from center bypass passage (21) to return passage (14).

At the same time, all of oil in cylinder (1) flows ports (9) and (10) and back to return line (13)
through passages (27) and (28), respectively.

As a result, there is no hydraulic control on the blade because of no oil supply to cylinder (1). In
turn, the blade is kept on the ground surface.

Line Relief/Make-up Valve

Line relief and make-up valve (17) is installed in the circuit for the head end of blade cylinder (1).

When the circuit pressure increases excessively (beyond the relief setting) with valve (22) in
NEUTRAL, valve (17) is open and allows excess oil to vent from the circuit. In addition, when the

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023
E70B TRACK-TYPE EXCAVATOR 5TG00001-UP (MACHINE) POWERED ... Page 152 of 152

negative pressure (vacuum) occurs in the circuit, the make-up part of this valve sends part of return
oil to the circuit with the negative pressure as make-up oil.

Thus, this valve prevents occurrence of too high oil pressure and/or vacuum condition.

Copyright 1993 - 2023 Caterpillar Inc. Tue Jan 3 08:16:34 UTC+0800 2023
All Rights Reserved.
Private Network For SIS Licensees.

https://127.0.0.1/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/siswe... 1/3/2023