Effect of Gear's Surfaces Roughness and Dimensions to Friction Moment in Drive Differental of Car

This paper focuses on analyzing the relationship of gear's surface roughness and dimensions to friction moment in drive differental of car when the gear pairs rotate around a symmetry axis. The simulation has determined the relationship of tooth surface contact roughness and cylinder radius on the ratio of input acting load and frictional moment helps to determine mechanical efficiency of gear transmission. The analyzing friction moment, which depends on roughness level and dimensions, can be applied for any similar contact surface: in case of increasing roughness, the dependence of friction moment on acting load become non-linear and confirmation in experiments. The driving differental efficiency is measured in experiments according to SAE J1266-2001 standards. In experiment process, at 50% loading mode, measured results diffence by under to 8.9 % compared with simulation. This proves that the established model closely describes physical processes in the differential system and the dynamic model is suitable.