Tribo-dynamics of differential hypoid gear pairs

This paper presents a multi-body dynamics model of hypoid gear pairs, showing the interactions between gear pair dynamics, NVH and friction in the thermo-elastohydrodynamic teeth pair conjunctions during meshing. The multi-body model consists of a two-degree of freedom torsional model developed in the ADAMS environment. The coefficient of friction is calculated using an analytical formula for non-Newtonian behaviour of a thin lubricant film. Additionally, road data and aerodynamic effects are used in the form of resisting torque applied to the output side of the gear pair. Sinusoidal engine torque variation is also included to represent engine torsional response. Results are presented for a light truck in both low speed city driving condition in 2ndgear and steady state cruising in 4th gear. Transmission efficiency is obtained under both conditions.Transmission performance under both cold and hot steady state cycles within the New European Driving Cycle (NEDC) is assessed.