On the Design of Planetary Gear Reducer with Simple Planet Gears

Planetary gear trains are commonly used in various transmissions due to the following reasons: compact size, light weight, and multi-degrees of freedom. For example, planetary gear trains can be designed for following functions: gear reducers for power machinery, internal gear hubs for bicycle, gear increasers for wind generator, gear reducers for robot. In general, the reduction of non-coupled planetary gear train is less than 10. The purpose of this paper is to introduce the planetary gear train with high reduction ratio. Coupled planetary gear train can be designed to has high reduction ratio. Hence, this paper focuses on innovative, kinematic, and engineering design of coupled planetary gear train with high reduction ratio. The coupled planetary gear train synthesized in this paper is a planetary gear train with simple planet gears. It can be used as the gear reducer for a robot. Refer to the train value equation, the reduction-ratio equation of coupled planetary gear train is derived for the design purpose. Then, the coupled planetary coupled gear train with simple planet gears is synthesized based on the above reduction-ratio equation. Finally, the corresponding engineering design drawing is accomplished.