Effect of Impact Load on Transient Elastohydrodynamic Lubrication of Involute Spur Gears

Nonstationary elastohydrodynamic lubrication (EHL) of an involute spur gear is a very complex problem. A full transient EHL solution of an involute spur gear is obtained by utilizing the multigrid method, which takes the variation in equivalent curvature, entrainment velocity, and load with time along the line of action into consideration. The lubricant thermal and rheological effects are ignored and the gear teeth are assumed to be rigid in the model as far as tooth flexure is concerned. The influences of load spectrum and impact on EHL are analyzed in this article. Over a meshing cycle of a tooth pair, initially the load is carried by two contacting tooth pairs and then there is a transition to single tooth pair, followed by a final transition to shared loading between two tooth pairs. The impact load when the teeth come into action is taken into consideration. The results show that the transient effects have a strong influence on the maximum pressure and minimum film thickness. The load spectrum plays an important role in EHL of gears.