This document provides an introduction to gear cutting and gear drives. It discusses that gears are an important part of power transmission systems used in various machines. Gears are classified based on the position of shaft axes and peripheral velocity. Common gear materials include various grades of steel, cast iron, aluminum, and bronze. Selection of gear material depends on the power transmitted, size, service period, accuracy needs, and manufacturing method. Gear drives effectively transmit power but require more space and are more expensive than other drives. They provide high transmission efficiency but tooth wear can occur over time.

1. BRAINWARE UNIVERSITY
NAME : DEBABRATA MONDAL
WELCOME
STUDENT CODE : BWU/DME/21/006
SUBJECT CODE: DME403
SUBJECT NAME: production technology
DEPARTMENT: MECHANICAL ENGINEERING

2. GEAR CUTTING

3. INTRODUCTION TO GEAR CUTTING.
 Gear is one of the important machine tool elements which is
an integral and inevitable part of power transmission
system.
 They find applications in Automobiles, gear boxes, oil
engines, machine tools, industrial machinery, agricultural
machinery, geared motors etc.
 To meet the difficult service conditions the gear should have
robust construction, reliable performance, high efficiency,
economy and long life.
 The gear drive should be free from noise and should ensure
high load carrying capacity at constant load ratio.

4. FUNCTION OF GEAR
1. To transmit torque from the driving shaft to driven shaft.
2. To reduce the speed generated by prime mover.
3. To change the direction of rotation through idlers.

5. CLASSIFICATION OF GEAR
The gears are classified as fallows:
1.According to the position of axes of shafts.
A. When shaft axes parallel:
 Spur gear
 Helical gears
 Herringbone gears
 Rack and pinion
B. When shaft axes intersecting
 Straight bevel gears
 Spiral bevel gears
C. When shaft axes non-intersecting and non parallel
 Hypoid gears
 Worm gears
 Screw gears

6. CLASSIFICATION OF GEAR
2. According to the peripheral velocity of the gears
 Low-velocity gears
 Medium velocity gears
 High velocity gears
3. According to the type of gears
 External gear
 Internal gear
 Rack and pinion
4. According to the position of teeth on the gear surface
 Straight gear
 Inclined gear
 Curved gear

7. GEAR MATERIALS
1. Metallic Materials
A. Ferrous metals - For high load.
 Cast iron
 Cast steel
 Medium and high carbon steels
 Alloy steel
B. Non-ferrous metals- For light load.
 Aluminium
 Bronze
2. Non- metallic materials
 Wood
 Plastic or fibre

8. SELECTION OF GEAR MATERIALS
The proper selection of gear material depends on :-
 Amount of power to be transmitted.
 Size and weight of the gear.
 Service period of the gear.
 Degree of accuracy required.
 Method of manufacture to be used.

9. ADVANTAGES OF GEAR DRIVES
1. Transmit more power than other type of drive.
2. Transmission efficiency is high.
3. It requires less space.
4. Maintenance is easy.
5. They have zero slip.
6. They have good durability and precision.

10. DISADVANTAGES OF GEAR DRIVES
1. Gear design and manufacturing is expensive.
2. Installation is difficult.
3. Tooth wear may occur during power transmission.
4. Inaccuracies in gear tooth cause noise and vibrations.

11. Thank you