The effect on dynamics of using various transmission designs for two-stage cycloidal speed reducers

Abstract

This paper investigates different transmission methods for a two-stage speed reducer by analyzing component motion and stress conditions during reducer operation. First, an exemplar (set) speed-reducing ratio is used to develop four differently structured two-stage speed reducers: a traditional design using two serially connected single-stage speed reducers, an Rotate Vector (RV) reducer constructed by serially connecting a cycloid speed reducer and an involute planet gear reducer, and two new concept designs. The first new concept named “New design 1” has a pin component in which a cam pair and pins connect two-stage cycloidal gears having different tooth numbers. The second new concept named “New design 2” has a center disc component in which a cam pair symmetrically connects two-stage cycloid gears with different tooth numbers. These four structural types of two-stage speed reducer form the basis for a system dynamics analysis model used to analyze the main components’ motion and stress variation conditions. Besides, this study also carries out the cycloid internal gear (nonpinwheel design) to replace the pinwheel in these four-structured two-stage speed reducers. The results highlight the differences and shortcomings of the four transmissions with pinwheel and nonpinwheel designs, including the dynamic load imbalance and stress peaks phenomena caused by design inadequacies.