Dynamic and tribological analysis of a toroidal CVT

The continuously variable transmission investigated in this paper works with contacts in the elastohydrodynamic regime of lubrication, thus the tangential forces are transmitted between elements through the shearing the lubricant film. The behavior of the lubricant film when subjected to shear depends of the nature of the lubricant and the relative motion between the contacting surfaces. In this paper a non-Newtonian behavior is assumed for the lubricant while the relative motion is determined for every point on the contact area by kinematic methods. The net tractive force in the sliding direction, and the spin torque are evaluated and from these the power losses in the contacts are calculated. The dynamic behavior of the device is evaluated taking into account the rheological behavior of the lubricant.