1. GEAR DRIVE
 Power transmission is the movement of energy
from its place of generation to a location where it
is applied to performing useful work.
 A gear is a component within a transmission
device that transmits rotational force to another
gear or device .

2.  It transmit exact velocity ratio .
 It may be used to transmit large
powers
 It has high efficiency.
 It has reliable service .
 It has compact layout
Advantages of Gear Drive

3. Disadvantages of Gear Drive
 The manufacture of gears
require special tools and
equipment
 The error in cutting teeth may
cause vibration and noise during
operation .

4. Types of Gears
Spur Gear
 Teeth is parallel to axis of
rotation
 Transmit power from one
shaft to another parallel
shaft
 Used in Electric screwdriver,
oscillating sprinkler, windup
alarm clock, washing
machine and clothes dryer

5. External & Internal Gear
 An external gear is one
with the teeth formed on
the outer surface of a
cylinder or cone.
 Conversely, an internal
gear is one with the teeth
formed on the inner surface
of a cylinder or cone.

6. Helical Gear
 The teeth on helical gears are
cut at an angle to the face of
the gear
 This gradual engagement
makes helical gears operate
much more smoothly and
quietly than spur gears

7. Bevel Gear
 Bevel gears are useful when the
direction of a shaft's rotation
needs to be changed
 The teeth on bevel gears can be
straight, spiral or hypoid
 locomotives, marine applications,
automobiles, printing presses,
cooling towers, power plants,
steel plants, railway track
inspection machines, etc.

8.  Hypoid gears resemble spiral
bevel gears except the shaft axes
do not intersect.
 Usually require some of the most
viscous types of gear oil to avoid
it being extruded from the mating
tooth faces.
 Which are normally straight cut
bevel gears in motor vehicle
axles.
Hypoid Gear

9. Worm and Worm Gear
 Worm gears are used when large
gear reductions are needed. It is
common for worm gears to have
reductions of 20:1, and even up to
300:1 or greater
 Many worm gears have an interesting
property that no other gear set has: the
worm can easily turn the gear, but the
gear cannot turn the worm
 Worm gears are used widely in
material handling and transportation
machinery, machine tools,
automobiles etc

10. Rack and Pinion
 It is Special case of a spur gear
where it is made of infinite
diameter so that the pitch
surface is a plane .
 It is used in a lathe in which the
rack transmits motion to the
saddle .

11. Non-Circular Gear
 A non-circular gear (NCG) is a
special gear design with special
characteristics and purpose.
 Textile machines,
potentiometers, CVTs
(continuously variable
transmissions), window shade
panel drives, mechanical presses,
high torque hydraulic engines.

12. Crown Gear
A crown gear can only
mesh accurately with
another bevel gear

13. Sun and Planet Gear
 A gear train having a relative
motion of axes is called a
planetary or an epicyclic gear
train
 Important application of
epicyclic gears are in
transmission, computing devices,
wrists watches, hoists, back gear
of lathe etc.

14. Harmonic Drive Gear
 Is a special type of
mechanical gear system that can
improve certain characteristics
compared to traditional gearing
systems
 typically used in industrial motion
control, machine tool, printing
machine, robotics and aerospace.
 for gear reduction but may also be used
to increase rotational speed, or for
differential gearing.

15. 1. Grease lubrication
Grease lubrication is suitable for any gear
system that is open or enclosed, so long as it runs
at low speed.
2. Splash lubrication
Splash lubrication is the normal method for
lubricating spur, helical, bevel and worm gears.
3. Spray lubrication
For the higher speed units (10 to 20 m/s
peripheral speed)
Lubricant for Gear