Series: The number of sets of planetary gears. Since a set of planetary gears can not meet the large transmission ratio, sometimes 2 or 3 sets are required to meet the requirements of the user's larger transmission ratio. Due to the increase in the number of planetary gears, the length of the 2 or 3 speed reducer will be If there is an increase, the efficiency will decrease. Return gap: The output end is fixed, the input end rotates clockwise and counterclockwise, so that the input end produces a rated torque +-2% torque, the input end of the reducer has a slight angular displacement, this angular displacement is the return clearance. It is a "point", which is one-sixtieth of a degree. Some people call it a backlash. With the continuous development of the reducer industry, more and more enterprises have applied the reducer. The planetary reducer is an industrial product. The planetary reducer is a communication mechanism whose structure is tightly coupled to the gear box by an internal ring gear. On the housing, the center of the ring gear has a sun gear driven by external power, and a set of planetary gear sets equated by three gears on the tray between the two, the set of planet gears rely on the output shaft, The inner ring gear and the sun tooth support float during the period; when the input side power drives the sun tooth, the planetary gear can be driven to rotate, and follow the track of the inner ring gear to revolve along the center, and the rotation of the planet drives the output of the output shaft connected to the tray. power. The speed converter of the gear is used to decelerate the number of revolutions of the motor (motor) to the required number of revolutions, and to obtain a mechanism with a large torque. In the gear mechanism for transmitting power and motion, the planetary reducer is a precision reducer with a reduction ratio of 0.1 rpm to 0.5 rpm.