A Simple Thermal Correction for Large Spin Traction Curves

Abstract

Presented in this paper is a simple design technique, based upon energy equivalence methods, to predict the thermally influenced large spin traction curves from a single nonspin large slip traction curve. The performance characteristics of variable speed traction drives is very closely linked to the rheological behavior of the fluid in the contact. At moderate values of spin the traction force can be predicted quite accurately from the Johnson and Tevaarwerk model. Their model is completely isothermal in nature. As the spin increases a definite discrepancy occurs between predicted and measured data and this discrepancy grows with increasing spin. Elastic effects in the fluid are negligible at these larger spin values and therefore the shearing is purely dissipative in nature. The observed discrepancy is thought to be caused by the heating of the material in the contact and the loss of limiting strength accompained by this. The model presented in this paper reduces the discrepancy between isothermally predicted spin traction and the thermally affected traction.