Dynamics of Chain CVT Drives: Effects of Friction Characteristic

A chain CVT is a type of friction-limited continuously variable transmission that provides a continuum of gear ratios with fewer moving parts. The dynamic performance and torque capacity of a chain CVT drive rely significantly on the friction characteristic of the contact patch between the chain and the pulley. Since the friction characteristic of the contact patch may vary in accordance with the loading and design configurations, it is crucial to study the influence of friction characteristic on the performance of a CVT. Two different mathematical models of friction, which characterize different operating/loading conditions, are embedded into a detailed planar multibody model of chain CVT in order to understand the various friction-induced effects in the system. The mathematical models, the computational scheme, and the results corresponding to different loading scenarios are discussed. The results discuss the influence of friction characteristics on the dynamic performance, the axial force requirements, and the torque transmitting capacity of a chain CVT drive.