Speed Ratio Control Characteristics of a Metal V-Belt Continuously Variable Transmission (1st Report, Effect of Belt Clamp Force on the Dynamics of the CVT without Load)

摘要

The dynamics of speed ratio control system of a metal V-belt CVT depends upon the clamp force characteristics at a concerned speed ratio. The system is getting unstable in the region of maximum reduction ratio at no load where the speed ratio changes easily by a small change in clamp force ratio. This paper clarifies this phenomenon by making analyses on the steady state relation between the clamp force ratio and speed ratio on the basis of a friction drive theory, and on the linearized motion control. The parameter defined by the change in the clamp force ratio per unit change in the speed ratio varies the damping ratio of the system. Especially in the reduction ratio range the damping ratio becomes small, which explains the instability observed in the experiments.