This document summarizes different types of gears classified based on their axis of rotation. It describes spur gears that have parallel axes for transferring power between parallel shafts. Helical gears are also discussed, which have twisted teeth oblique to the axis and produce thrust in the axial direction. Rack gears are explained as bars containing teeth that mesh with gears to convert rotary to linear motion. Bevel gears connect perpendicular shafts and can have straight or spiral teeth. Screw gears transmit power between non-parallel and non-intersecting shafts. Finally, worm gears are detailed as providing large reduction ratios using a threaded worm to drive a worm wheel.

1. SEMINAR
ON

3. CLASSIFICATION OF GEARS
Parallel Axis
Intersecting Axis
Non-intersecting
and Non-parallel
Axis
• Spur Gear
• Helical Gear
• Rack Gear
• Internal Gear
• Miter Gears
• Straight Bevel Gears
• Spiral Bevel Gears
• Worm and Worm Gear
• Screw Gear

4. SPUR GEAR
 Teeth are straight & parallel to shaft
axis. Transmit power and motion
between rotating parallel shafts.
 FEATURES:
• Easy to manufacture
• Their will be no axial
force
• Relative easy to produce
high quality gears.
• The commonest type
 APPLICATIONS:
• Transmission components

5. HELICAL GEAR
 Teeth are twisted oblique to the gear
axis.
 FEATURES:
• Has higher strength
compared with spur gear.
• Effective in reducing
noise & vibration with
spur gear.
• Gears in mesh produce
thrust forces in axial
direction.
 APPLICATIONS:
• Transmission components
• Automobiles
• Speed reducers

6. RACK GEAR
 The rack is a bar containing teeth on
one face for meshing with a gear.
 Racks with machined ends can be
joined together to make any desired
length.
 FEATURES:
• Change a rotary motion
into a rectilinear motion
 APPLICATIONS:
• A transfer system for machine tools,
printing press, robots, etc.
• Steering system in vehicles

7. BEVEL GEAR
 One of a pair of gears used to connect two
shafts whose axis interact and the pitch
surfaces are cones
 FEATURES:
• Bevel gears are useful when
the direction of a shaft's
rotation needs to be changed
• They are usually mounted on
shafts that are 90 degrees
apart, but can be designed to
work at other angles as well
• The teeth on bevel gears can
be straight or spiral.
 APPLICATTIONS:
• marine applications, automobiles,
printing presses, cooling towers,
power plants, steel plants, railway
track inspection machines, etc.

8. SCREW GEAR
 A helical gear that transmit power from
one shaft to another, non parallel ,non
interacting shafts
 FEATURES:
• Used in a speed reducer
and/or a multiplying gear
• Tends to wear as the gear
come in sliding contact
• Not suitable for
transmission of high
horsepower
 APPLICATIONS:
• Driving gear for automobiles
• Automatic machines that require
intricate movement

9. WORM & WORM GEAR
 Worm is a shank having at least one
complete tooth9thread) around the pitch
surface; the driver of a worm wheel
• Worm wheel is a teeth cut on an angle to be
driven by a worm
 FEATURES:
• Provides large reduction
ratios for a given center
distance
• Quiet and smooth action
• A worm wheel is not
feasible to drive a worm
except for special occasions
 APPLICATIONS:
• Worm gears are used widely in material
handling and transportation machinery,
machine tools, automobiles etc

11. Praveen Kumar Kharb