JABALPUR ENGINEERING

COLLEGE
TRAINING REPORT
SUBMITTED IN REQUIREMENT FOR
FOUR WEEK INDUSTRIAL TRAINING

AT

VE COMMERCIAL VEHICLES
DEWAS
(From 06 JUN to 06 JUL)

SUBMITTED TO:- SUBMITTED BY:-

PROF. A.K. JAIN Sir AKSHAT R. JAIN
Mechanical Engineering
Roll No - 0201ME201006

Department of
Mechanical Engineering
JABALPUR ENGINEERING COLLEGE
JABALPUR

PREFACE
As a part of course curriculum of B.TECH.(AICTE) we were
asked to undergo 4 weeks of summer training in any
organisation so as to give us exposure to practical learning to
get us familiar with various activities taking place in the
organization in any department related to our field.

I have put my sincere efforts to accomplish my objectives

within the stipulated time. Despite all limitations, obstructs,
hurdles and hindrances, I have toiled and worked to my
optimum potential to achieve desired goals. With the kind of
help and genuine interest and the guidance of my supervisor,
I’m presenting this hand carved effort.

ACKNOWLEDGEMENT

3
Training is systematic way to gain new knowledge. It is
possible only in the light of guidance, advice and help from a
number of sources without which a learner is a soldier in the
vast uncharted sea without radar.

I would like to express a deep sense of thanks and gratitude to

our project guide, our co-supervisor, Prof. A.K. Jain Sir for
guiding us immensely through the course of the project. His
constructive advice and constant motivation has been
responsible for the successful completion of this project.

Also, I would like to thanks Mr. Anil Kumar Sharma Sir (AM
– HR & Center Of Excellence, Unit 3) for giving me such
special opportuinity to undergo training in VE Commercial
Vehicles (Dewas).
 
 
 

TABLE OF CONTENTS

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Introduction………………………………………………………………………………………………………..…6-9

Design Calculations and Drawings…………………………………………………………….……….12-16

Gearbox Operation…………………………………………………………………………………………….17-20
Comments and Conclusions…………………………………………………………………………………….20
Appendix…………………………………………………………………………………………………………………21

Reference……………………………………………………………………………………………………………….22

List of Figures | Figure1 Spur gear.............................Error! Bookmark not defined.

Figure 2 Helical gear.......................................................................................................8
Figure 3 Bevel gear.........................................................................................................9
Figure 4 Worm gear.......................................................................................................9
Figure 5 First Gear........................................................................................................18
Figure 6 Second Gear...................................................................................................19
Figure 7 Third Gear......................................................................................................20
Figure 8 Fourth Gear....................................................................................................20
Figure 8 Reverse Gear..................................................................................................21
Figure 9 Stress Machine...............................................................................................22

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 1.0 Introduction |

A gear is a machine element used to transmit motion between rotating

shafts/wheels when the center distance between the shafts is not too large. They

provide a positive drive, maintaining exact velocity ratios between driving and driven

shafts.

A transmission is a speed and power changing device installed at some point

between the engine and driving wheels of the vehicle. It provides a means for

changing the ratio between engine rpm (revolutions per minutes) and driving wheel

rpm to best meet each particular driving situation. Given in order to get smooth

starts and have power to pass and climb hills, a power ratio must be provided to

multiply the torque and turning effort of the engine. Also required is a speed ration

to avoid the need for extremely high engine rpm at high road speed. The

transmission is geared to perform these functions.

Power transmission gears are usually made from chromium molybdenum steel

which provides good toughness and resistance to wear. Some (low power) gears are

made from sintered metal (powered metal). Non-power gears can be made of almost

any material including composites for quieter running non lubricated arrangements.

Most gears are run lubricated either by regular maintenance lubrication or by

being run semi submersed in oil or spray lubricated.

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1.1 Gears usage:

It plays an important role in our daily life basis, starting from our washing

machines in houses till the heavy vehicles in mining and construction places.

Accordingly for each machine or vehicle. Gears are simply a means of applying

leverage to rotating parts. A modern transmission provides both speeds and power.

The engineer who designed it selected the gear sizes that would give the best all

around performance. It is geared to a power ratio that puts the car in motion, and

then it shifts, or it shifted, to one or more speed ratios that keeps it rolling.

1.2 Types of gearboxes:

Different types of gearbox are used. These types are manual gear, automatic,

semi-automatic, and bicycle gearing. For each gearbox, several gears are utilized such

as spur, helical, bevel, hypoid and worm gears. Each type of gear is explained briefly

below:

• Spur Gear

This is the most common type

of gear tooth shape, and

would be fitted in the

accessory gearbox of an

engine. The gear can be Figure 1: Spur gears formed either internally or

externally. An internal gear would be used where a change in speed is

required without changing the axis of drive. External spur gears are used

where a change in speed is required but the shafts lie parallel to each other.

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 Spur gears may be noisy owing to the impact of the teeth upon each other

as they rotate.

 Helical Gear

Figure 2: Helical Gear

This is a smoother, less noisy running gear than the spur gear, the teeth are cut on a

curve or helix, which produces a sliding engagement of the teeth, and more than one

tooth is in engagement at any one time. A disadvantage of this gear for is that it

produces a heavy axial load. This disadvantage can be eliminated by using double

helical gears, with the teeth being cut in an opposite helix. An advantage of this type

of gear is that it can accept and transmit a higher loading than a spur gear of the

same size. Helical gears might be fitted in the reduction gearbox of a turbo prop

engine or in the gearbox of an ordinary car.

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 Bevel Gear

Figure 3: Bevel Gear

This type of gear is used when the drive is required to be transmitted through an

angle; in this case the gear teeth can be straight cut or in a helical form, when the axis

of the shafts intersect. An example of use would be for the transmission of drive from

the main rotating assembly on a gas turbine to the accessory gearbox, or the tail rotor

gearbox on a helicopter.

 Worm Gear

This gear form is used where there is a large resistance to turning, and a

large reduction in speed is required. The worm teeth are similar to a multi

start thread, and are cut at an angle or on the skew, in which case the gear

may be called a skew gear.

Figure 4: Worm Gear

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 Automatic gear box : An automatic transmission (also called

automatic gearbox) is a type of motor vehicle transmission that can

automatically change gear ratios as the vehicle moves, freeing the

driver from having to shift gears manually. Most automatic

transmissions have a defined set of gear ranges, often with a parking

pawl feature that locks the output shaft of the transmission stroke

face to keep the vehicle from rolling either forward or backward. [2]

 A semi-automatic transmission (SAT) (also known as a clutch-less

manual transmission, automated manual transmission, flappy-paddle

gearbox, or paddle-shift gearbox) is an automobile transmission that

does not change gears automatically, but rather facilitates manual

gear changes by dispensing with the need to press a clutch pedal at

the same time as changing gears. It uses electronic sensors,

pneumatics, processors and actuators to execute gear shifts on the

command of the driver or by a computer. This removes the need for a

clutch pedal which the driver otherwise needs to depress before

making a gear change, since the clutch itself is actuated by electronic

equipment which can synchronize the timing and torque required to

make quick, smooth gear shifts. The system was designed by

automobile manufacturers to provide a better driving experience

through fast overtaking maneuvers on highways

 Bicycle gearing: Bicycles usually have a system for selecting different

gear ratios. There are two main types: derailleur gears and hub gears.

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The derailleur type is the most common, and the most visible, using

sprocket gears. Typically there are several gears available on the rear

sprocket assembly, attached to the rear wheel. A few more sprockets

are usually added to the front assembly as well. Multiplying the

number of sprocket gears in front by the number to the rear gives the

number of gear ratios, often called "speeds".

The type of gearbox used in this project is a manual Nissan car

gearbox. The main specification of the gear box we selected consists

of main shaft, counter shaft, and housing. Gears are placed in the

main shaft and counter shaft to transmit the motion, whereas

bearings to hold and support the shafts inside the housing. The

selected gearbox has specifications of helical and spur gearings.

Gearbox importance appears in transmitting the work output from the

pistons to the car wheels. Owing to the gear ratios, gears such as

reverse gear, low gear, second gear, high gear, & overdrive rotate in

different rotational speeds. For example in high gear, the gear ratio is

1 to 1, thus the output shaft turns at the same speed as the

crankshaft.

The objective of this project is to illustrate how a gearbox works and

show the function of each component inside it.

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2.0 Design Calculations and Drawings

The following table shows the gearbox components and their specifications:
Part List

Item Part Name Quantity Picture Material

1 Clutch Shaft 1 C.I.

1st speed synchronizer

2 1 Steel
assembly

3 1st synchronizer hub 1 Steel

12
4 2nd gear 1 Steel

5 3rd gear 1 Steel

6 1st gear 1 Steel

13
7 4th gear 1 Steel

2nd & 3rd synchronizer

8 1 Steel
hub

9 Reverse Idler 3 C.I.

10 Countershaft 1 C.I.

14
11 Countershaft gear 1 Steel

12 2nd gear & 3rd gear input 1 Steel

13 Reverse gear 1 Steel

15
14 Bearing 5 Steel

15 Drive gear 3 Steel

16 Housing 1 C.I

16
3.0 Gearbox Operation |

The gearbox principle is based on receiving the motion from the piston,

where the clutch controls whether to connect the motion to the clutch gear or

not, and pass it through the main shaft. Within the main shaft, the arrangement

of the gears decides the passage of the motion, thus, leading to specific speed of

the drive gear. In our gearbox, 5 transmissions were found and explained as

follows:

3.1 First Gear: the clutch connects the motion to the clutch gear then to the counter

shaft which provides the motion to the 1 st gear input. Next, the 1st gear input causes

the 1st gear to rotate and thus leading to rotate the drive shaft. The 1 st gear diameter

is 30 mm which is relatively large. Though the large gear gives low speed, very large

power is obtained. In the first gear, the gear ratio is 3 to 1.

Figure 5: First Gear

3.2 Second Gear: again when the clutch connects the motion to the clutch

gear, the counter shaft is directed to transmit the motion to the 2 nd gear

input, hence the 2nd gear rotates leading to the drive shaft to rotate with

2.4 to 1 gear ratio; . The 2nd gear diameter is 25 mm, less power

but higher speed is provided compared to the 1st gear.

Figure 6: Second Gear

3.3 Third Gear: as dog clutch clutches the 3 rd gear of 20 mm in diameter, the

motion passes through the counter shaft leading to the drive shaft to gear

ratio of 1.4 to . Compared to 2nd gear, the drive shaft rotates in

very high speed with lower power.

 Figure 7: Third Gear

3.4 Fourth Gear: Owing to the straight pass of motion, the gear ratio of the 4 th

gear becomes 1 to 1; the driven gear is the same as the driving gear.

Figure 8 Fourth Gear

 3.5 Reverse Gear: Though, the motion of the reverse gear is similar to the first

gear, the motion of delivered to the drive shaft is in the opposite

direction. This happens due to the reverse idler which exists between the

main shaft and the countershaft.

Figure 1 Reverse Gear

4.0 Comments and Conclusion |

Unfortunately, many difficulties were met in the project from the

beginning of how to choose a gearbox till the end of how to assemble the parts

again after disassembling. Some of these difficulties are listed below:

• A gearbox was bought and disassembled and then it was

discovered that the gearbox was automatic and it had to be left and

another one had to be brought instead. 3 weeks were lost for this

problem.

• During disassembling the new gearbox, as we had no experience in

such thing, little help was asked. However, wrong instructions were given

by the technicians. On the other hand, one student from another group
 helped us and we got back on the right track. 2 weeks were spent for

disassembling.

• Press machine (Appendix 1) was used to dislocate the case out of

the main shaft. For future improvements for the following batch that they

should stick to the schedule so that they don’t run out of time.

Finally, the objective of the project is successfully accomplished; the

gearbox functionality is known and the role of each component inside it is

fully

understandable.
5.0 Appendix |

This figure shows the stress machine used to dislocate the case out of the
shaft:

Figure 9 Stress machine

6.0 References |
 [1] Lahue, K. C., Petersen's big book of auto repair, In-text: (Lahue, 1976.)

[2] Autoweb.com, Leading Transmission Maker Predicts Major Shift to

Automatics in Heavy Vehicles, Accessed 27 May 2014.

Brain, M., HowStuffWorks "How Sequential Gearboxes Work", Intext: (Brain,

2014), Bibliography: Brain, M, and Accessed 27 May 2014.