Tractions at the spinning point contacts of a variable ratio friction drive

Abstract

Prediction of the available traction forces at the contacts is a major difficulty in the design of lubricated rolling contact friction drives. Data obtained on disc machines are not directly applicable because of the variations in geometry as ratio changes are made, and because of the inherent relative angular velocity or ‘spin’ at the contacts. An attempt is made to apply current theories on traction in elastohydrodynamic lubrication to the special case of friction drive contacts. The results are compared with experimental data obtained on a traction test rig based upon a variable ratio toroidal drive.