1. By
Avinash N. Fulbaria

2.  Introduction
Applications
Types of Gear Train
Introduction to Compound Gear Train
 Equation Derivation for Compound Gear
Train.
 Reference

3.  A gear train is a combination
of gears used to transmit
motion and power from one
shaft to another
 It is also known as train of
toothed wheels
 Gear trains may use spur,
bevel or spiral gears.

4.  Used to either speed up or stepped
down the speed of driven shaft and
follower.
 Examples :- 1) Automobile
2) Clocks
3) Ships
4) Watches
5) Lathe Machines etc.

5.  Simple gear trains
 Compound gear trains
 Riveted gear trains
 Epicyclic gear trains

6. INTRODUCTION
Each of the
intermediate
gears carries two
gears except the
driving and driven
shafts.
 Examples :- used
in headstock of
lathe machine.

7.  As gear A drives gear B .
 Gear C is rigidly mounted on gear on the
axis of gear B so speed will be same.
 Gear C drives the gear D

8. 1) For gear A and B :
NB ∕ NA = tA ∕ tB = dA ∕ dB….(1)
2) For gear C and D :
ND ∕ NC = tC ∕ tD = dC ∕ dD…(2)
Multiplying (1) and (2)
NB ∕ NA × ND ∕ NC = tA ∕ tB × tC ∕ tD
= dA ∕ dB × dC ∕
dD

9. But NB = NC (Since gear B and C are fixed
on same shaft )
Therefore,
Velocity ratio, ND∕ NA= tA ∕ tB × tC ∕ tD
= dA ∕ dB × dC ∕
dD

10. ND∕ NA=
Product of number of teeth on drivers
Product of number of teeth on followers
ND∕ NA =
Product of diameters of drivers
Product of diameters of followers

11. 1) Higher and lower velocity ratio can be
obtained .
2) Velocity ratio for the given distance
between driving and driven shaft can be
obtained.

12. Kenneth J. Waldron, Gary L. Kizel,
Kinematics, Dynamics and Design of
Machinery ,Second Edition, 2010

13. END