Structure and Characteristic

An internal gear ring (A) is firmly attached to the gearbox housing. There is an external power to drive the sun gear (B) located in the center of the internal gear ring. Between two parts, there is a planetary gear set (C) consisting of three gears that are equally assembled onto the carrier. This set of planetary gears are supported by an output shaft, internal gear ring and sun gear to float among them. When the power of the output end drives the sun gear, the sun gear can drive planetary gears to self rotate and follow the trajectory of the internal gear ring to perform the revolution around the center. The rotation of planetary gears will drive the output shaft connected with the carrier to transmit power.


The transmission of planetary speed reducers differs from that of typical traditional gears. Traditional gears are only driven by the engaged surfaces between large and small gears and all the loadings are concentrated on the contact point, which tends to wear and crack the gears easily. In the case of high-speed ratio, more couples of engaged gears are required for multiple stages. This not only takes a large amount of space but also generates more abrading attrition. The clearance between the couple of engaged reducer gears in each stage also accumulates, and all the above reduce the efficiency greatly.

When the planetary speed reducer drives, the sun gear, planetary gears and internal gear ring are loaded on six contact points and are in mesh with internal gear trajectory to evenly distribute the impact load spread out over 360 degrees. This can reduce the abrasion between gears and prevent the gears from cracking. Planetary gears rotate in a floating way so their clearance is almost insignificant. Each stage of speed reduction will only need the engagement of intermittent gears, so the volume is relatively minimized and the maximum efficiency can reach up to 97%.