1. To Our Presentaion

2. Presentation Topic :
Gear & Gear
Trains

3. GEAR

4. Types of Gear
Gear
Spur Gear Helical Gear
Herringbone
Gear
Bevel Gear Worm Gear

5. Spur Gear
– Used to transmit rotary
between parallel shafts.

6. Helical Gear
– Used to transmit rotary
motion between parallel or
nonparallel shaft.

7. Herringbone Gear
– A Herringbone Gear consists
basically of two rows of helical teeth
cut into one gear.
– The axial thrust forces are cancelled
by direct subtraction.
– Herringbone Gears are used for
heavy and continuous load
applications.

8. Bevel Gear
– Used to transmit rotary
motion between intersecting
shafts.

9. Worm Gear
– Used to transmit rotary
motion between
nonparallel nonintersecting
shafts.

10. Gear Trains

11. Introduction
Two or more gears are made to mesh with each
other to transmit power from one shaft to another.
Such a combination is called gear train or train of
toothed wheels.

12. Gear Trains
Simple
gear train
Compound
gear train
Reverted
gear train
Epicyclic
gear train
Types of Gear Trains

13. Simple Gear Train
When there is only one gear on
each shaft it is known as simple
gear train. The gears are
represented by their pitch circles.

14. Compound gear train
When there are more than one gear
on a shaft,it is called a compound
train of gear.

15. Reverted Gear Train
When the axes of the first gear (i.e.
first driver) and the last gear (i.e. last
driven or follower) are co-axial,then
the gear train is known as reverted
gear train.

16. Epicyclic Gear Train
the axes of the shafts, over which the gears are
mounted, may move relative to a fixed axis.
 If the motion is called epicyclic and the gear trains
arranged in such a manner that one or more of
their members move upon and around another
member are known as epicyclic gear trains

17. Velocity Ratioz of Epicyclic Gear
Train
The following two methods may be used for finding out the
velocity ratio of an epicyclic gear train.
1. Tabular method, and
2. Algebraic method.

18. Compound Epicyclic Gear
Train—Sun and Planet Gear

19. Gear Terminology
 Diametral pitch
 Module
 Circular pitch
 Gear ratio
 Pressure line
 Pressure angle
 Pitch angle
 Contact ratio
 Path of approach
 Path of recess
 Path of contact
 Arc of recess
 Arc of contact
 Angle of action
 Pitch circle
 Addendum circle
 Dedendum circle
 Clearance
 Backlash
 Full depth
 Face width