Elastohydrodynamic lubrication of hypoid gear pairs at high loads

Abstract

Differential hypoid gear pairs have been the mechanism of choice for high-torque capacity final drives in all forms of vehicles, at least since mid-19th century. Transmission efficiency as well noise and vibration concerns requires combined elastohydrodynamic and tooth contact analysis of hypoid gear teeth pairs through mesh. Although such analyses have been reported for general cases of elliptical point contact conjunctions with angled flow entrainment, they do not comply with the prevailing load and kinematic conditions in differential gears. In particular, teeth pair contacts are subject to significant loads of order of several kilo Newtons requiring solution to the elastohydrodynamic lubrication problem at such high loads. The current analysis reports solutions for rolling and sliding elastohydrodynamics of hypoid gear teeth pairs at realistic drive torques, not hitherto reported in literature.