With the development of industrial technology, frequency conversion control motors have been widely used in rail transit, wind power generation, industrial frequency conversion and other fields. As an important component of the motor reducer, the stability of gear system has the vital influence on the normal operation of the motor system. In this paper, the dynamic characteristics of gear bearing system with rough tooth surface wear are studied. The gear-bearing system model considering time-varying meshing stiffness, backlash, friction and oil film force of sliding bearing is established. Then, the fractal theory is used to describe the surface roughness of gear, and the minimum oil film thickness and the wear coefficient at different meshing points are calculated according to the surface topography height. Next, based on the Hertz theory and the Archard theory, the tooth surface wear is calculated, and the backlash with tooth surface wear is obtained, which is substituted into the gear bearing system. Finally, the Runge Kutta method is used to solve the dynamic equations of the system, and the phase diagrams, the Poincaré section diagrams, the bifurcation diagrams and the three-dimensional spectrum diagrams of the system response are obtained. Furthermore, the effects of fractal dimension, damping ratio and average meshing stiffness on the system response are analyzed.
 

gear,bearing,fractal theory,Archard theory,Dynamic