Effect of Surface Roughness Pattern on the Tribological Performance of Helical Gears

The surface roughness is one of the important topics in the mechanical elements. Usually, the standard deviation of asperities height is considered as the only key factor in the contact of rough surfaces while the surface pattern or the orientation of asperities is of vital importance as well. In this research, effect of different methods of surface finishing on the performance of a pair of helical gears is studied. A computer program is used to generate surface roughness profiles with different roughness patterns. This roughness profile is then used as an input in another simulation program which predicts the performance of helical gears under mixed-lubrication regime using the load-sharing concept. The results indicate that in the gears with transverse surface roughness pattern a larger portion of the load is carried by asperities and a higher friction coefficient occurs compared to longitudinal and isotropic roughness pattern. The predicted results are shown to be in good agreement with the results of another study on the effect of surface roughness pattern on the performance of journal bearings.