Design and dynamic transmission error analysis of a new type of cycloidal-pin reducer with a rotatable output-pin mechanism

A new type of one-stage precision cycloidal-pin reducer is designed and explored in this study. The design innovatively replaces the fixed output-pin mechanism of conventional cycloidal-pin reducers with a rotatable output-pin mechanism, thereby transforming the sliding contact between the output-pin and the output-hole into a rolling contact. This new structural design is found to significantly improve the transmission efficiency of the reducer. To evaluate the dynamic transmission error (DTE) characteristics of the proposed reducer, a general dynamic model of the cycloidal-pin transmission system considering the influences of multi-source error factors on the geometry of the main components is established. The geometric error of the component is determined by taking random values within a given design-tolerance zone. The geometric error distribution introduced using this method can well match the actual machining situation. Finally, the DTEs of the new reducers with three different tolerance designs are analyzed numerically and tested experimentally. The results show that the new reducer with a reasonable tolerance design can achieve high transmission accuracy and has the potential for application in the joints of industrial robots.