How does a planetary reducer work?

27 Mar.,2025

 

Planetary gearbox, also called planetary reducer, is one of the transmission devices widely used in motion control. In a gear train, there is more than one gear that rotates and revolves around a certain axis. This kind of gear train is called a planetary gear train. A reducer that operates on this principle is called a planetary reducer.

Planetary reducer (planetary reducer) is an industrial product with a wide range of uses, which can reduce the speed of the motor while increasing the output torque. The planetary reducer can be used as a supporting component in industries such as lifting, excavation, transportation, and construction.

Overview:

Number of stages: the number of sets of planetary gears. Because one set of planetary gears cannot meet the larger transmission ratio, sometimes 2 or 3 sets are required to meet the user’s requirements for larger transmission ratios. Due to the increase in the number of planetary gears, the length of the 2-stage or 3-stage reducer will be reduced. Increased, efficiency will decrease. Return clearance: Fix the output end and rotate the input end clockwise and counterclockwise to make the input end produce rated torque +-2% torque, there is a slight angular displacement at the input end of the reducer, and this angular displacement is the return clearance. Unit It is a “point”, which is one-sixtieth of a degree. Some people call it backlash. With the continuous development of the reducer industry, more and more companies are using reducers. Planetary reducers are an industrial product. Planetary reducers are a transmission mechanism whose structure is tightly combined with the gear box by an internal gear ring. On the shell, there is a sun gear driven by external power at the center of the ring gear. Between the two, there is a planetary gear set composed of three gears equally divided on the tray. This set of planetary gears relies on the output shaft, The inner gear ring and sun gear support float during the period; when the input side power drives the sun gear, it can drive the planetary gear to rotate, and follow the inner gear ring track along the center to revolve, the rotation of the planet drives the output shaft connected to the tray to output power. A mechanism that uses a gear speed converter to decelerate the number of revolutions of the motor (motor) to the required number of revolutions and obtain a larger torque. In the reducer mechanism used to transmit power and motion, the planetary reducer is a precision reducer, and the reduction ratio can be accurate to 0.1 rpm-0.5 rpm.

 

Working principle

An inner gear ring (A) is tightly connected to the gearbox housing, and the center of the ring gear has a sun gear (B) driven by external power. In between, there is a set of three gears that are divided into equal parts. The planetary gear set on the tray (C) This set of planetary gears relies on the output shaft, the inner gear ring and the sun gear to support the floating during the period; when the planetary reducer drives the sun gear by the input side power, it can drive the planetary gears to rotate and follow The trajectory of the inner gear ring revolves along the center, and the rotation of the star drives the output shaft connected to the tray to output power.

The structure of planetary reducer

The main transmission structure of the planetary reducer is: bearing, planetary gear, sun gear, and inner ring gear.