The document discusses the design and fabrication of an automobile gearbox. It outlines the objectives to design a helical gearbox and study gear manufacturing processes. It then discusses various aspects of gearbox design like gear ratios, materials selection, automatic vs manual transmissions, and presents some results like pitch line velocities. Market research was also conducted to determine costs. The conclusion states that gear and shaft design is complete and fabrication will begin soon.

1. Design and Fabrication of GearBox
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

2. AIM: To design and fabricate a
automobile gearbox
Objectives
•To design a Helical gear box
•Study of various gear manufacturing
processes
•Fabrication of gear box
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

3. Representation of Gearbox
Motor
Gear box Gear
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

4. Market Survey
Market research was done at following places
regarding type and cost calculation of the
Gearbox.
•Sokhi heli-wom gears pvt.ltd in Ghaziabad
•Hi-tech gears in Manesar
•Junk market in Mayapuri
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

5. Gearbox
A transmission or gearbox provides speed and tor
que conversions from a rotating power source to
another device using gear ratios, including for a
motor vehicle partly because of the limitations of
internal combustion engines. Torque converters,
hydraulics, electrical power and hybrid
configurations may also be used for the same
purpose.
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

6. Uses of Gearbox
•Gearbox has different uses at different places.
•In Automobiles, engine speed is about 5000
rpm ,but wheels rotate at 1000 rpm.Machine tool
spindle rotates at 50 rpm while the motor is at
1440 rpm.
•Automobile gearbox can have variable output
and input speeds ,and few reduction ratios in
between.
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

7. Gearbox types
It can be classified as
•Manual
•Automatic
Manual Gearbox can be further divided as
5.Synchromesh and Non Synchromesh
Non synchromesh includes :sliding mesh type
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

8. Synchromesh GearBox
Constant Mesh Gearbox where diagonal cut
helical gear sets are constantly "meshed"
together, and a dog clutch is used for changing
gears. On synchromesh boxes, friction cones or
"synchro-rings" are used in addition to the dog
clutch. This type of gearbox is used in modern
cars and trucks these days.
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

9. Material Selection
• Keeping in mind cost effectiveness. It was
intended to design a general purpose
Gearbox, where cheaper materials would be
used.
• So, Plain Carbon Steel will be used for moving
components and Cast iron for Frames and
bodies ,because of intricate shape they can be
easily casted.
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

10. Materials contd.
• Plain Carbon Steel with 0.4% carbon or EN8
material is selcted for shaft.
• Further,Hot rolled being cheaper than cold rolled
and heat treated materials , hot rolled will be
selcted.
• For gears : 30 Ni 4 Cr 1 is selected with
Sut=1500Mpa
• For gears, additonal cheap alloying element,such
as manganese (0.87%),to make it Strong , giving
ultimate strength of 600 Mpa.(P.S.G Design data
book 1.13)
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

11. Automatic Gearbox
• This type of transmission are easy to use.
Automatic transmission will select an
appropriate gear ratio without any operator
intervention .
• Sun and planet gear are mainly used
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

12. Design of Automobile Gearbox
• Gearbox are incorporated to match performance
of variable speed internal combustion engine.
• Lowest reduction ratio is needed at highest
speed of operation, and vice versa, values of
these reduction ratio lies b/w 3.5 to 4.5 for cars
and 5 to 7 for commercial vehicles.Gearbox
provides reduction ratio between 1:1 to 1:4 for
cars to 1:1 to 1:7 for commercial vehicles.
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

13. Special features of Automobile Gear
box
• Universally accepted number of gear ratios is
4.These four are in geometric progression,
However ,overdrive gear is provided to
enhance performance at higher speeds
• Additional reduction ratio is provided to
enhance performance during higher gradient
operation.
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

14. Results Obtained
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

15. Gear Ratios
1st gear ratio 4:1
2nd gear ratio 2.52:1
3rd gear ratio 1.58:1
4th gear ratio 1:1
5th gear ratio 1.58:1
6th gear ratio 2.52:1
7th gear ratio 4:1
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

16. Layout
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

17. Results
Pitch line velocities for different gear pairs
Gear Pair Velocity(km/hr)
GH 33.9
AB 67.9
CD 57
EF 44.7
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

18. Gantt Chart
Task Start Date End Date Days Completed Days Remaining
1. Problem Formulation 09/01/09 09/30/09 21 0
2.Literature and market survey 10/01/09 10/31/09 31 0
3.Design of gears and shafts 11/01/09 11/30/09 25 5
4. Cutting of gears 01/20/10 02/28/10 0 38
5. Gear assembling and casing 03/01/10 03/31/10 0 31
6. Final Report 04/01/10 04/30/10 0 30
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

19. Conclusion
Designing of gears and shafts has been done and near
future we will be starting with fabrication of gearbox.
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

20. Acknowledgement
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon

21. Bibliography
•P.S.G Design Data book
•Handbook for engineers
•Material Science By Rk Rajput
•Mechanical System Design By S.P . Patil
•Theory of machine By Khurmi & Gupta
•Machine Design By Khurmi & Gupta
Department of Mechanical and Automobile Engineering,
26/11/2009
Institute of Technology and Management, Gurgaon