Introduction and explain types of gear train

1. SUBMITED BY
ANURAG PANDEY
131MC00234

2. Gear train is a combination of gears used to transmit the motion from one
shaft to another. It is required to obtain large speed reduction within a
small space.
The following main types of gear trains are
 Simple gear train
 Compound gear train
 Reverted gear train
 Planetary or epicyclic gear train

3.  Each shaft support one gear.
 A series of gears capable of receiving
and transmitting motion from one
gear axes remain fixed relative to the
frame and each gear is on separated
shaft.
 A simple gear train also have bevel
gear

4.  When the series of gears are
connected in such a way that two
or more gears rotate about an axis
with the same angular velocity ; it
is known as compound gear train.

5.  If the axis of the first and last
wheel of a compound gear
coincide it is called reverted gear
train.
 Such arrangement is used in clock
in simple lathe where ‘back gear’
is used to give slow speed to the
chuck.
 If r is the pitch circle radius of a
gear,
r1+ r2 = r3 + r4

6.  When there exist a relative
motion of axes in a gear train, it is
called an epicyclic gear train.
 In epicyclic gear train the axis of
at least one of the gears also
move to the relative frame.
 If arm ‘a’ is fixed. Turn ‘s’
through x revolution in the clock
wise direction. Assuming
clockwise motion of wheel as a
positive and counter clockwise
motion as negative.

7.  Revolution made by ‘a’ =0
 Revolution made by ‘s’=x
Revolution made by ‘p’ = -(Ts / Tp )x
Large speed reduction are possible with epicyclic gears.
In general gears trains have two degrees of freedom.