Planetary gear reducer is a kind of important equipment widely used in industrial machinery transmission system, its main function is to provide greater output torque through deceleration, and can change the speed of input shaft. There are coaxial input, bevel gear input, helical gear input, bevel gear-helical gear input; output shaft form with expansion disk hollow shaft, involute spline hollow shaft, with flat key hollow shaft, involute spline solid shaft; mounting form horizontal mounting, vertical mounting, torque arm mounting, and so on.