Influences of transient impact and vibration on the lubrication performance of spur gears

In this paper, the mathematical model of gear elastohydrodynamic lubrication is presented. The transient impact operating condition and underdamped load condition are considered. Taking thermal effect and squeeze effect into account, the full numerical solution of gear pairs is obtained. In this numerical calculation, multigrid method is applied to compute the film pressure; multigrid integration technique is used to calculate the solid surface deformation; column by column scanning technique is employed to calculate temperature. The simulation results show that an entrapped film dimple forms under transient impact condition; transient impact causes remarkable increases in film pressure and film temperature. Compared with the normal case the minimum thickness of the impact case is smaller, which is not beneficial to teeth lubrication. Thermal effect induces some decreases in film thickness because of the viscosity–temperature relationship. Vibrational load with high damped frequency causes greater increases in film thickness and greater decreases in the coefficient of friction than that of low damped frequency. However, the film temperature of high damped frequency is higher than that of low damped frequency.