Planetary gear reducer is also known as planetary reducer, servo reducer. In the family of reducers, planetary reducers are widely used in servo motors, stepper motors, DC motors and other transmission systems for their small size, high transmission efficiency, wide range of deceleration, high precision and many other advantages. It is mainly used to reduce the rotational speed, increasing torque and reduce the load/motor inertia ratio on the premise of ensuring the precision transmission.

For structural reasons, the minimum single-stage reduction of planetary reducer is 3, and the maximum is generally not more than 10. The common reduction ratio is 3/4/5/6/8/10. The number of reducer series is generally not more than 3, but some large reduction ratio customized reducer has four-stage reduction. Compared with other reducers, planetary reducers have the characteristics of high rigidity, high precision (single stage can achieve less than 1 minute), high transmission efficiency (single stage in 97% - 98%), high torque / volume ratio, lifelong maintenance-free and so on. Because of these characteristics, planetary reducers are mostly installed on stepper motors and servo motors to reduce speed, improve torque, and match inertia. The maximum rated input speed of planetary reducer can reach 18 000 rpm (related to the size of the reducer itself, the greater the reducer, the smaller the rated input speed) or more. The working temperature is generally between - 25 ℃ and 100 ℃. The working temperature can be changed by changing the grease.