Epicyclic Gear Train
If the axis of the shafts, over which the gear is compound mounted, are moving relative to the fixed axis, the gear train is known as an epicyclical gear train. In the simple, compound and reverted gear train, the axis of the shafts is fixed. But in the epicyclic gear train, the shaft axis is not fixed but is moving relative to ‘ the fixed axis.
The epicyclic gear trains are useful for transmitting high-velocity ratios with the gear of moderate size in a relatively lesser area.
Advantage of epicyclic gear trains as compared to the reverted gear train and compound gear trains
- They take less space and also have lightweight because they share the load between several gear meshes.
- It has smaller and stiffer components which reduce noise and vibration with increased efficiency.
- The input and output shafts of the epicyclic train are concentric so the driver and driven equipment can be mounted in line, providing additional space savings.
- In very high horsepower units, the components of parallel shaft designs become so bulky that epicyclié trains gain a further economic advantage.
Epicyclic Gear Train Disadvantage
- It has a complex design as compared to others.
- Driver and driven instrumentality should be in line to avoid further gearing.