a small presentation about gearbox automobile process mfg

1. GEARBOX PROCESS

2. MANUFACTURING
TECHNOLOGY
Introduction
 Gears are used extensively for transmission of power. They find application in Automobiles,
gear boxes, oil engines, machine tools, industrial machinery, agricultural machinery, geared
motors etc.
 To meet the strenuous service conditions the gears should have robust construction, reliable
performance, high efficiency, economy and long life. Also, the gears should be fatigue free and
free from high stresses to avoid their frequent failures.
 The gear drives should be free form noise and should ensure high load carrying capacity at
constant velocity ratio.
 To meet all the above conditions, the gear manufacture has become a highly specialized field.

3. 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.

4. UESE 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.

5. 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

6. 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.

7. LAYOUT

8. MANUFACTURING
TECHNOLOGY
Materials used in Gear Manufacturing Process
 The various materials used for gears include a wide variety of cast irons, non ferrous
materials
Selection of Gear Materials Depends upon
 Type of service
Peripheral speed
Degree of accuracy required
Method of manufacture
Required dimensions & weight of the drive Allowable stress
Shock resistance
Wear resistance.

9. MANUFACTURING
TECHNOLOGY
 Gear Manufacturing can be divided into two categories, Forming and Machining.
Forming consists of direct casting, molding, drawing, or extrusion of tooth forms in molten,
powdered, or heat softened materials. Machining involves roughing and finishing operations.

10. GEAR FORMING PROCESS
Extrusion
 Extrusion is a manufacturing process where material is drawn through a die, giving the
material a new cross-sectional shape that is usually constant throughout the lengths of the
material. Dies with multiple openings can extrude several strands simultaneously, as well as create
hollow cross- sections by using a pin (mandrel) in the die.

11. GEAR FORMING PROCESS
Extrusion
 Extrusion process is used to form teeth on long rods, which are then cut into usable lengths
and machined for bores and keyways etc. Nonferrous materials such as aluminum and copper
alloys are commonly extruded rather than steels. Results in good surface finish with clean edges
and pore free dense structure with higher strength
 Small sized gear can also be made by extrusion process. There is saving in material &
machining time.
 This method can produce any shape of tooth & it is suitable for high volume production.
Gears produced by extrusion find application in watches, clocks, type writers etc.

12. GEAR FORMING PROCESS
 Stamping
Sheet metal can be stamped with tooth shapes to form low precision gears at low cost in high
quantities. Surface finish and accuracy are poor.
 Application
Toy gears, hand operated machine gears, slow speed mechanism gears
 Precision stamping
The dies are made of higher precision with close tolerances. The stamped gears will not have
burrs.
 Application
Clock gears, watch gears etc.

13. GEAR FORMING PROCESS
Stamping
 After stamping, the gears are shaved; they give best finish & accuracy .
 The materials which can be stamped are: low, medium & high carbon steels, stainless steel.
 This method is suitable for large volume production.

14. POWDER METALLURGY
 Sintering Process
 The metal powder is pressed in dies to convert into tooth shape, after which the
product is sintered. After sintering, the gear may be coined to increase density &
surface finish. This method is usually used only for small gears.

15. POWDER METALLURGY

16. SINTERING PROCESS

17. GEAR MACHINING OR
GENERATING PROCESS
 Roughing processes include milling the tooth shape with formed
cutters or generating the shape with a rack cutter, shaping cutter or a
hob cutter.
 Despite its name, the roughing processes actually produce a
smooth and accurate gear tooth. Only for high precision and quiet
running, the secondary finishing operation is justified at added cost

18. GEAR SHAPING PROCESS
 Gear shaping uses a cutting tool in the shape of a gear which is
reciprocated axially across the gear blank to cut the teeth while the
blank rotates around the shaper tool.
 It is true shape generation process in that the gear shaped tool cuts
itself into mesh with the gear blank.

19. GEAR SHAPING BY DISC
CUTTER
 The disc cutter shape
confirms the gear tooth
shape. Each gear needs
separate cutter. However,
with 8 to 10 std. cutters, gears
from 121 to 120 teeth can be
cut with fair accuracy. Tooth
is cut one by one by plunging
the rotating cutter in to the
blank.

20. GEAR SHAPING BY END
MILL CUTTER
 he End mill cutter shape confirms the gear tooth shape. Each tooth is cut at time and
then indexed for next Tooth space for cutting. A set of 10 cutters will do for 12 to 120
teeth gears. Suited for small volume production of low precision gears.

21. ADVANTAGES
1. The gears produced by the method are of very high accuracy.
2. Both internal & external gears can be cut by this process.
3. Non – conventional types of gears can also be cut by this method.

22. DISADVANTAGES
1. The production rate with gear shaper is lower than
Hobbing.
2. There is no cutting on the return stroke in a gear shaper.
3. Worm & worm wheels can’t be generated on a gear shaper.

23. CONCLUSION
 Designing of gears and shafts has been done and near future
we will be starting with fabrication of gearbox.