chapter  19
52 Pages

Split Gear Drives

An epicyclic gearing system is particularly well suited for achieving a high reduction ratio in a relatively small, power-dense package. The principles of epicyclic gearing are well established, and historically the epicyclic gear has been used for almost as long as the simple form of gear, which comprises a single pinion and a wheel. Basically, an epicyclic gear consists of three coaxial torquecarrying members, which, quite arbitrarily, can be an input, output, or stationary reaction members:

1. A sun gear, which has external teeth 2. An annulus gear, which is a ring that has teeth on its inner surface 3. A planet carrier, which supports the bearing spindles of a number of identical planet

pinions that have external teeth

As with any type of power transmission system, the engineer is faced with many analytical challenges during the design phase to ensure a highly reliable power train is obtained. In the case of an epicyclical gearing system, this challenge is particularly dif€cult due to the complex interaction of revolving and rotating components as they transmit power.