Meshing characteristic analysis of spur gear pair with tooth surface wear fault based on improved fractal method

The three-dimensional (3D) fractal contact model of the interaction between gear teeth is established considering the actual surface morphology of gear teeth. The time-varying meshing stiffness (TVMS) model of spur gear pair is established and verified by finite element (FE) method based on the loaded tooth contact analysis (LTCA) method and considering the influence of friction between the gear teeth. The meshing characteristics and wear depth under tooth surface wear fault condition are analyzed by incorporating the Archard’s wear model, considering the effects of tooth roughness and friction. The effects of friction and fractal parameters on TVMS and wear depth are analyzed. Friction causes the TVMS at the pitch line position to mutate. The increase in friction coefficient and decrease in fractal dimension result in the increase in wear depth and the decrease in TVMS within the region where two pairs of gear teeth engage in meshing. TVMS shows partial linearity with the change of fractal dimension. The influence of fractal dimension on TVMS and wear depth becomes increasingly prominent with the progression of wear cycles, surpassing the influence of friction coefficient.