Planetary gears are often referred to as three-component mechanisms, and the three components refer to sun wheels, planets and gears, respectively. If the three components to determine the relationship between the movement, in general, the first need to fix one of the components, and then determine who is the master, and determine the speed of the active parts and the direction of rotation, the results of passive speed, rotation direction to determine The.

Simple (single row) planetary gear mechanism is the basis of the transmission mechanism, usually the automatic transmission of the transmission mechanism by two rows or three rows of planetary gear mechanism. The simple planetary gear mechanism includes a sun gear, a plurality of planetary gears and a gear ring, wherein the planetary gear machining is supported by a fixed shaft of the carrier, allowing the planet wheel to rotate on the support shaft. Planetary gears and adjacent sun gears, the ring gear is always in the often engaged state, usually using helical gears to improve the smoothness of the work.