On the lobe profile design in a cycloid reducer using instant velocity center

A cycloid speed reducer is one of the rotational speed regulation devices of the machinery. It has advantages of the higher reduction ratio, the higher accuracy, the easier adjustment of the transmission ratio and the smaller workspace than any other kinds of the reducer. This paper proposes a simple and exact approach for the lobe profile design of the cycloid plate gear, which is a main part of the cycloid reducer, by means of the principle of the instant velocity center in the general contact mechanism and the homogeneous coordinate transformation. It is considered the four types of the cycloid reducers in this study: the stationary ring gear type epicycloid reducer, the rotating ring gear type epicycloid reducer, the stationary ring gear type hypocycloid reducer and the rotating ring gear type hypocycloid reducer. Design examples for the four types of the cycloid reducers are presented to simulate the operation and to demonstrate the feasibility of this approach using a computer-aided program developed on C++ language.