Effect of Gear Tooth Friction on the Vibro-Acoustics of Hypoid Gears

This study examines the significance of gear tooth friction force in differential gear vibration and sound radiation. The analysis employs an Elastohydrodynamic Lubrication (EHL) model for hypoid gears to calculate the friction force and study its effect on the vibro-acoustic characteristics of differential gear set. Firstly, the input geometric and kinematic data required for the EHL simulations are obtained from the loaded Tooth Contact Analysis (TCA). Then, the EHL analysis is performed to calculate the elastohydrodynamic pressure and film thickness. The results are then applied to calculate the effective viscosity and the shear stress on the gear tooth, which yields the gear tooth friction force. This friction force is used to derive the coefficient of friction that is applied in the dynamic response calculation of hypoid gears using a multi-body nonlinear dynamic model. Time-varying dynamic bearing forces are calculated from the dynamic response . Finally, the significance of friction on vibro-acoustics of hypoid gears is measured by comparing the dynamic mesh force in the presence and absence of friction.