An analytical modelling approach for overall torsional stiffness of rotate vector reducer

Analytical modelling for overall torsional stiffness of rotate vector (RV) reducer has been a meaningful research priority owing to its over-constrained and multi-crank actuation structural characteristics. This paper presents an analytical modelling approach for overall torsional stiffness of RV reducer. The approach starts from analysing stiffness topological relations among all components, in order to convert the stiffness modelling of entire machine into the stiffness calculation of several subsystems. Then, time-varying meshing information including contact points, contact pins, contact deformation, and multi-tooth mesh stiffness, are precisely identified with consideration of profile modification and loads. Subsequently, the nonlinear stiffness of turning-arm bearings and support bearings is calculated through the force analysis of crankshafts. On this basis, the overall torsional stiffness model of RV reducer is developed, which concerns various stiffness parameters of high-speed stage and low-speed stage. Furthermore, the sensitivities and influences of stiffness parameters on the overall torsional stiffness of RV reducer are systematically analysed. Finally, the effectiveness and accuracy of the proposed model are validated by the physical prototype test. The outcomes of this paper are beneficial to the stiffness prediction and design of RV reducer according to its performance requirement.