Transient EHL analysis of helical gears

The paper describes a transient elastohydrodynamic lubrication (EHL) model of involute helical gears and examines the extent to which the behaviour can be taken to be approximated using equivalent point and line contact steady state approaches. Significant transient effects are found near the ends of the contact line, particularly at locations where tip relief is active. Different tip relief profiles considered show that high stress concentrations and poor lubricant films may be avoided with suitable profile choice. Finally, 3D results of a preliminary evaluation of surface roughness effects on local contact stress and EHL film thickness are described.