The effect on dynamics of using a new transmission design for eccentric speed reducers

•A new transmission design for eccentric speed reducers is proposed.•A dynamic analysis model is constructed for testing new transmission designs.•The solution for the cross piece design is the round disc design.•Double-gear design is superior to the single-gear design in dynamic balance.•The shortcomings of the involute gear used in eccentric speed reducers are shown.

This paper proposes a new transmission design for eccentric speed reducers that differs from that used with a traditional cycloid speed reducer. The main difference, other than the input and output shafts, is that it uses the internal gear as its fixed part and transmission between the external gear and output shaft occurs via pins connected to a drive plate. In this paper, gearing theory is used to construct a mathematical model of the involute external and internal gears, based on which the trajectory equations, component geometry, and reducer kinematics can be derived. A dynamics analysis model is also constructed and used to test the feasibility of two types of drive plate designs — a cross piece and a round disc, each with a single-gear and double-gear design. The stress results show the infeasibility of the cross drive plate versus the feasibility of the round disc drive plate. An additional kinematic analysis provides evidence that the design of the gear tooth profile also affects the machine transmission and can lead to vibration and stress fluctuation.