Transient non-Newtonian elastohydrodynamics of rough meshing hypoid gear teeth subjected to complex contact kinematics

Predictions are provided for mixed elastohydrodynamic conditions of meshing hyoid gear teeth pairs of light truck differentials. Under transient conditions, pertaining to vehicle cruising or in urban driving, the lubricant is subjected to non-Newtonian traction. The meshing teeth are subjected to complex kinematics, comprising rolling, sliding and squeeze film motions. Furthermore, instantaneously varying angled lubricant flow into the contact constitutes a precession of contact footprint, further complicating the prevailing conditions. The inclusion of all these interacting kinematics shows that the lubricant film thickness, shear characteristics and transmission efficiency are significantly affected by the ensuing transience. This cannot be adequately represented by the usual quasi-steady analyses. The in-depth detailed analysis of the hypoid gear pairs of vehicular differentials constitutes the main contribution of the paper.