Performance prediction method of cycloidal speed reducers

Abstract

The cycloidal speed reducer is used in industry universally. In order to know the influence of the design parameters on the reducer performance, this study proposes a prediction method which cannot only estimate the stability but also forecast the power loss to identify the performance differences of various designs. The design of reducers in this paper follows non-pin designs so that the transmission uses a cycloidal gear and a cycloid internal gear. Firstly, several design cases considering different number and pitch radii of output rollers are used to explain the prediction method and establish statistical math models in which the data is obtained from the reducer dynamic analysis. Then, the variation coefficient of kinematic and stress data is used to predict the stability (or vibrations risk) and efficiency (or power loss), respectively. The results indicate that the effect of the number of output rollers on the stability is greater than that of the pitch radius of the output rollers. Although increasing the number of output rollers may increase the risk of vibrations, the power loss of the speed reducer can be reduced. Besides, the proposed prediction method can also be applied to reducers with multi-cycloidal gears to investigate how non-pin designs affect their overall performance. The results confirm that the stability and efficiency is reduced significantly when the number of cycloidal gears is greater than two, and in such a case, the design of dual cycloidal gears is the best option.