Inefficiency predictions in a hypoid gear pair through tribodynamics analysis

A tribo-dynamics model, predicting the conjunctional inefficiency and dynamic response of automotive hypoid gear pairs is presented (dynamics coupled with analytical viscous and boundary friction models). The temperature rise at the centre of the conjunction is accounted for using a thermal network model and Time Temperature Superposition (TTS) method. Newtonian and non-Newtonian lubricant shear behaviour are considered with surface topography measurements of a run-in pinion. Inefficiency calculations are performed for typical automotive drive cycle snapshots. Precisely measured lubricant shear characterstics for lubricants with different viscosity modifiers and evolving surface topography are used in the transmission inefficiency study. The integrated thermal-tribodynamic analysis is shown to distinguish between different viscosity modifier types, an approach not hitherto reported in literature.