In the past research on the dynamics of gear system with pitting corrosion fault, the main concern is that the main factor affecting the dynamic response of gear system is attributed to the reduction of gear meshing stiffness, and the influence of the change of sliding friction force on the gear system response is largely ignored, and the tooth surface pitting fault will cause the increase of tooth surface roughness In addition, it is pointed out that when the tooth surface is slightly damaged, the gear friction excitation will become an important vibration source of the gear system, so the influence of the sliding friction force on the response of the gear system can not be ignored.
Therefore, the dynamic model of gear system considering the influence of sliding friction force is used to simulate and analyze the dynamic response of gear system from three aspects, that is, only considering stiffness excitation, only considering friction excitation, and comprehensively considering stiffness excitation and friction excitation.
In this paper, the early micro pitting fault of gear is simulated. Firstly, the model of early micro pitting fault is established, and the influence of pitting fault on meshing stiffness and friction excitation of gear is studied. Then three simulation cases are passed: case I (only considering stiffness excitation), case II (considering only friction excitation) and case III (considering both stiffness excitation and friction excitation) respectively The influence of different gear states (health, pitting-1, pitting-2, pitting-3) on the dynamic response of gear system; finally, through the comprehensive analysis of the above simulation cases, it is concluded that the influence of only considering the sliding friction force is almost as large as that of considering only the meshing stiffness of the gear at the early stage of micro pitting. However, with the increase of pitting failure, the influence of time-varying meshing stiffness is gradually more than that of sliding friction.