Epicyclic gear train for power transmission

1. Epicyclic gear train
• Gears are the circular bodies in which teeths have cut.
• When a number of gears are arranged to the same shaft or different
shaft, they are termed as gear trains.
• Gears are generally used to increase the speed of rotation or
decrease the speed of rotation.
• There are number of types of gears and gear trains.
1. Based on

2. Terms related to gear train-
• Driver gear-The gear which is given rotation is called as Driver gear.
• Driven gear-The gear which is being rotated by the driver gear,is
called as driven gear.
• Speed ratio- The ratio of speed of driver gear to driven gear is called
as speed ratio.
Mathemetically,
Speed ratio = N2/N1
• Train value- The ratio of number of teeths in driver gear to driven
gear is known as Train value.
Mathemetically,
Train value = T1/T2
N2/N1 = T1/T2

3. Types of Gear trains-
1.Simple gear train

5. 2. Compound gear train

6. 3. Reverted gear train

7. 4. Epicyclic gear train

14. Step no Conditions of motion Revolutions of elements
Arm C Gear A Gear B
1 Arm fixed-gear A
rotates through + 1
revolution i.e. 1 rev.
anticlockwise
0 +1 -TA/TB
2 Arm fixed-gear A
rotates through + x
revolutions
0 +x -x ×TA/TB
3 Add + y revolutions
to all element
+y +y +y
4 Total motion +y x+y +y+-x ×TA/TB