CIRCUIT A PRESSION PRIORITAIRE PROPORTIONNELLE COMPENSEE
3PC
CENTRE FORMATION CASABLANCA
S3PC CONTROL VALVE
PROPORTIONAL PRIORITY, PRESSER
COMPENSTED (PPPC0 HYDRAULIC SYSTEM
OPERATION
3PC HYDRAULIC SYSTEM BLOCK DIAGRAM
HOLD
Third Fourth
Pilot Function Function
Accumulator
Tilt Lift
Manifold Cylinder Cylinders
Inlet Tilt Lift Auxiliary Auxiliary
Pump
Manifold Control Control Control Control
Control
Valve Valve Valve Valve
Valve
Hydraulic Piston
Pump
Tank
Wired To
Controller
Tilt Lift Auxiliary Auxiliary
Pilot Pilot Solenoid Solenoid
Valve Valve Valves Valves
STEERING AND IMPLEMENT PUMP
CONSTANT FLOW
Margin
Spring
Actuator
Signal
Piston
Pressure
Bias
Spring
Orifice
Signal
Limiter
Margin
Swashplate Spool
To Control Pressure
Valve Group Cutoff Spool
3PC MAIN CONTROL VALVE GROUP
HOLD
Pilot
Accumulator Third Fourth
Function Function
Tilt Lift
Cylinder Cylinders
Pilot
Shutoff
Solenoid
Line
Lock Relief
Valve Valve
Pilot
Supply Makeup
Valve
Return
To
Tank Pressure
Reducing
Pressure Bridge
Valve
Compensator Passage
Valve
Pump
Supply
Signal Control
Duplication Spool
Valve Resolver
Valve
Orifice
Load
Signal
to Pump Signal
Limiter
Valve
Return
to
Tank
Pilot Control Pilot Control Pilot Control Pilot Control
Valve Valve Valve Valve
or or or or
Solenoid Valves Solenoid Valves Solenoid Valves Solenoid Valves
PILOT OPERATED CONTROL VALVE
HOLD To Signal
From Signal Duplicat ion Valve
Duplication Valve
From Previous
Resolver
Port A Port B Load Check
Spool
Pressure
Line Compensat or
Relief Valve Valve
Makeup Valve
Lock
Valve Bridge
Passage
Cont rol Feeder
Spool Passage
Int ernal
Passage
To / From Pilot To / From Pilot
Cont rol Valve Cont rol Valve
To Tank
PRESSURE COMPENSATOR VALVE OPERATION
From Signal
Duplication Valve
To Pump Control Signal
Valve and
Signal Relief Valve
To
Resolver
Signal
Valve
Duplication
Valve Valve A Valve B Valve C
Load
Check Spool
Pressure
Compensator
Valve
Spool
Pump Bridge Pump Feeder Pump
Supply Passage Supply Passage Supply
HOLD LOW PRESSURE HIGH PRESSURE
PILOT OPERATED CONTROL VALVE
HIGHEST CIRCUIT LOAD SIGNAL
To Next
From Signal Resolver
Duplication Valve
Load Check
Port A Port B Valve
Pressure
Line Compensat or
Relief Valve Valve
Makeup
Valve
Lock
Valve Bridge
Passage
Cont rol
Spool Feeder
Passage
To Pilot From Pilot
Cont rol Valve Cont rol Valve
To Tank
PILOT OPERATED CONTROL VALVE
LOWER CIRCUIT LOAD SIGNAL
To Next
From Signal Resolver
Duplication Valve
From Previous
Resolver
Load Check
Port A Port B Valve
Pressure
Line
Compensat or
Relief Valve
Valve
Makeup
Valve
Lock
Valve Bridge
Passage
Cont rol
Spool Feeder
Passage
From Pilot To Pilot
Cont rol Valve Cont rol Valve
To Tanks
3PC MAIN CONTROL VALVE GROUP
ACTIVE
Pilot
Accumulat or Third Fourth
Function Function
Tilt Lift
Cylinder Cylinders
Pilot
Shutoff
Solenoid Line
Lock Relief
Valve Valve
Pilot
Supply Makeup
Valve
Return
To
Tank Pressure
Reducing
Valve Pressure Bridge
Compensator Passage
Valve
Pump
Supply
Signal Control
Duplication Spool
Signal Valve Resolver
Drain Valve
Valve
Orifice
Load Signal
Signal Limiter
to Pump Valve
Return
To
Tank
Pilot Control Pilot Control Pilot Control Pilot Control
Valve Valve Valve Valve
or or or or
Solenoid Valves Solenoid Valves Solenoid Valves Solenoid Valves
Function CONTROLS FOR THE CONTROL VALVES
Lock
Valve
Pilot Oil
Pump Supply
To Next Resolver
Pump Supply ECM
From Signal To Next Resolver
Duplication Valve
From Signal
Duplication Valve
Orifice
Pilot Oil
Pilot Oil
Proportional Position
Pilot Control Solenoid Sensor
Valve
PILOT CONTROL Lever
VALVE Detent Plunger
HOLD Plate
Adjustment
Pin
Spring
Retainer
Plunger
Detent Coil
Spring
Spool
Spring
Orifice
Spring Pilot Supply
Chamber
From To To
Control Tank Control
Valve Valve
PILOT CONTROL
Lever
VALVE
Detent Plunger
SHIFT
Adjustment Pin Plate
Retainer Plunger Spring
Plunger
Detent Coil
Spool Spring
Spool
Orifice
Pilot Supply
From To To
Control Valve Tank Control Valve
PILOT CONTROL
VALVE Lever
IN DETENT Detent Plunger
Adjustment Pin
Plate
Retainer
Plunger
Detent Coil
Spool
Orifice
Pilot Supply
From To To
Control Valve Tank Control Valve
SOLENOID OPERATED CONTROL VALVE
HOLD
To Next
From Signal Resolver Valve
Duplication Valve
From Previous
Resolver Valve
Port A Port B
Load Check
Lock Spool
Valve Pressure
Compensator Valve
Line Relief
Bridge Passage
and
Makeup
Valve
Line Relief
Cont rol and
Spool Makeup Valve
Int ernal Feeder
Passage Passage
Proportional
Solenoid Proportional
Solenoid
Joystick Joystick
Control Control
Supply To
To Tank Passage Tank
SOLENOID OPERATED CONTROL VALVE
CIRCUIT ACTIVATED
To Next
From Signal Resolver Valve
Duplication Valve
From Previous
Resolver Valve
Port A Port B Load Check
Valve Pressure
Line Relief Lock Compensat or
and Valve Valve
Makeup
Valve Bridge Passage
Line Relief
Cont rol
and
Spool Makeup Valve
Int ernal
Feeder
Passage
Passage
Proportional
Solenoid
Proportional
Solenoid
Joystick Joystick
Control Supply Control
Passage
To
930G WHEEL LOADER PILOT OPERATED HYDRAULIC SYSTEM
Quick Coupler HOLD
and
Auxiliary Control
Valves
Manual Lowering Valve
Combination
Valve
Third Fourth
From Pilot Function Function
Steering Accumulator
Tilt Lift
Cylinder Cylinders
Return
Restrictor
To Manifold
Steering
Priority Valve
Inlet Tilt Lift Auxiliary Auxiliary
Manifold Control Control Control Control
Valve Valve Valve Valve
Pump
Control
Valve Tilt
Control
Valve
Hydraulic Piston
Pump
Tank
Drain Flow
Valve Control
Valve
Wired To Tilt Pilot
Controller Valve
Lift Pilot Auxiliary Auxiliary
Valve Pilot Pilot
Valve Valve
"H" SERIES MEDIUM WHEEL LOADER IMPLEMENT HYDRAULIC SYSTEM
HOLD / RIDE CONTROL AUTO / 9.7 KM/H (6 MPH) AND ABOVE
Tilt
Cylinder
Ride
Control Auxiliary
Lift Accumulator
Cylinders Function
Manual Load Check Head End Pilot Shutoff
Lower Valve Solenoid Valve Valve
Line Rod End
Valve Relief Solenoid Valve
Valves
Raise Pilot
Load Check Solenoid Valve Pilot
Valve Accumulator
Rackback Pilot
Solenoid Valve Ride Control
Lift Spool
Relief Valve
Tilt Spool Balance Pilot
Pressure Solenoid Pressure
Compensator Valve Reducing Steering
Valve Valve Pilot
Screen Supply
Resolver Pressure Balance (Command
Valve Compensator Valve Control
Valve Steering
only)
Signal
Relief
Signal Valve
Duplication
Valve Lower / Float
Dump Pilot
Pilot
Solenoid Valve Margin Relief
Solenoid Valve
Valve
Choke Check
Valve
Case
Drain
Filter
Tank
Pump
HYDRAULIC SCHEMATIC COLOR CODE
Black - Mechanical connection. Seal Red - High pressure oil
Dark Gray - Cutaway section Red/White Stripes - 1st pressure reduction
Light Gray - Surface color Red Crosshatch - 2nd reduction in pressure
White - Atmosphere or Pink - 3rd reduction in pressure
Air (No pressure)
Purple - Pneumatic pressure Red/Pink Stripes - Secondary source oil pressure
Yellow - Moving or activated components Orange - Pilot, charge, or Torque Converter oil
Cat Yellow - (R estricted usage) Orange / White Stripes -
Identification of components Reduced pilot, charge, or TC oil pressure
within a moving group
Orange Crosshatch - 2nd reduction in
Brown - Lubricating oil pilot, charge, or TC oil pressure.
Green - Tank, sump, or return oil Blue - Trapped oil
Green / White Stripes -
Scavenge Oil or Hydraulic Void
Centre de Formation - CASABLANCA
