Fast evaluation of friction forces in traction-drive contacts including thermal effects

In automotive traction drives, power is transmitted by friction forces. The friction forces result from the shear stresses developed in lubricated and highly loaded contacts between rolling bodies. Due to the kinematics of a traction drive, shear velocities occur in both the rolling direction and pe rpendicular to it. Due to these shear velocities and by normal pressure, th e lubricant is forced to build up shear stresses. The increase of the shear stresses may be modelled by a nonlinear viscous element. The describing di fferential equations are coupled by the equivalent shear stress, which defi nes the nonlinear behaviour of the element. A fast method is described to e valuate the coupled differential equations. By using a known analytical app roximation for the equivalent shear stress, the differential equations are decoupled and can be solved analytically. In an iterative procedure the equ ivalent shear stress is updated, and the complete solution is found. The it erative method is extended to account for thermal effects in the contact.