Reducer between the prime mover and work machine or actuator from the matching speed and torque transfer effect, reducer is a relatively sophisticated machinery reducer, using its purpose is to reduce speed and increase torque. The transmission of the series can be divided into single-stage and multi-stage reducer; wheel plant in accordance with the shape of the teeth can be divided into cylindrical gear reducer, bevel gear reducer and a cone - cylindrical gear reducer lead round; use servo motor output shaft diameter Use the form can not exceed the maximum shaft diameter; 2, if the calculations by the torque, speed planetary gear to meet the usual operation, but in the full output servo worm reducer, there is insufficient phenomenon, can drive the motor side of the do limiting control, or in the mechanical axis of torque protection, it is very necessary.