This document discusses different types of gears, including their defining characteristics, advantages, disadvantages, and applications. It describes internal and external gears, and various gear types based on axis positioning such as spur gears, helical gears, bevel gears, and worm gears. Each gear type is defined, and their uses in applications like washing machines, textile machines, and vehicle steering are outlined. The document also briefly covers herringbone gears.

1. TYPES OF GEARS
PRESENTER:
Shuvas Khanal [21131]
Arpan Koirala [21132]

2. INTERNAL GEAR
AND
EXTERNAL GEAR

3. According to the position of axes
of the shaft :
a. Parallel
 Spur Gear
 Helical Gear
 Rack and Pinion
b. Intersecting
 Bevel Gear
c. Non Intersecting and Non Parallel
 Worm Gears

4. SPUR GEAR
 Most commonly used Gear type.
 Teeth are parallel to the axis of the gear.
 Transmit power from one shaft to other
parallel shaft.

5.  Advantage:
 Low Cost
 Ease of manufacture
 Availability
 Disadvantage:
 Only works with mating gear
 Axis of each gear must be parallel
 Applications:
 Washing Machines, Rolling Mills, Marine Engines .

6. HELICAL GEAR
 Teeth are at an angle to the gear axis
 This gradual arrangement makes helical
gear Operate much more smoothly and
quietly than spur gear
 Can transmit power between Right angle
or Parallel Axis

7.  Advantage:
 Smooth and quiet due to gradual tooth engagements
 Parallel to perpendicular shaft arrangement
 Disadvantage:
 Difficult to Manufacture
 Cost is High
 Resulting axial thrust component
 Applications:
 Fertilizer industries, Printing industries, hearth moving industries, Conveyors,
Elevators

8. BEVEL GEAR
Useful when the direction of shaft location
has to be changed.
 Mounted on shaft that are 90deg apart, can
also be designed to work in other angles.
 Teeth can be straight, Spiral or Hypoid

9.  Advantage:
 Operate on Shafts intersecting at an Angle.
 Sliding friction will be low.
 Disadvantage:
 Assembled with respective shaft precisely.
 At high speed it will produce noise.
 Applications:
Textile Machine, Sewing Machine.

10. WORM GEAR
 Used when large Gear Reduction
is needed.
 Have good intersecting property.
 Used widely in material Handling
and transportation machinery,
machine tools etc.

11.  Advantage:
 Higher speed reduction could be secured; speed reduction could be secured
up to 300:1
 Worm and worm gears operate silently
 Disadvantage:
 Manufacturing cost is high as compared with manufacturing cost of bevel
gear
 Worm and worm gear set will have heavy power losses.
 Efficiency will be low
 Applications:
 Tuning Instruments, Lifts/Elevators.

12. RACK AND PINION
 Convert Rotational to Linear motion
 Round Gear – Pinion
 Flat or Straight Gear – Rack
 Best example is Vehicle Steering System.

13.  Advantage:
 Rack and pinion gives easier and more compact control over the vehicle
 Cheap, Compact, Robust
 Disadvantage:
 The rack and pinion can only work with certain levels of friction
 Applications:
 Rack Elevators, Steering

14. HERRINGBONE GEAR
 Two helical gears that have been placed
side by side as a mirrored pair.
 Referred to as “double helical”.
 No thrust loading on the bearings

15.  Advantage:
 The double helical form balances the inherent thrust forces
 Efficient transfer of torque and smooth motion at very high rotational
velocities
 Disadvantage:
 High cost due to special gear shaping.
 equipment and special cutting tools
 Applications:
 Used in Heavy Machineries

16. THANK YOU !