In addition to causing translation vibration of gear along the vertical engagement line, the friction moment will also form to restrict torsional vibration. When the lubrication of the tooth surface is poor or the tooth surface is slightly damaged, friction excitation becomes an important factor affecting the dynamic characteristics of gear transmission system.Since the friction arm, friction coefficient and friction direction are time-varying, multi-tooth meshing causes interaction and its dynamic behavior is complicated, it is necessary to accurately analyze the friction dynamic excitation mechanism of tooth surface and its influence on the dynamic characteristics of gear system.

Firstly, an accurate six-degree-of-freedom dynamic model considering the influence of friction force on tooth surface is established, in which time-varying characteristics such as meshing stiffness and friction coefficient of tooth surface need to be considered, and the relationship between tooth surface roughness and friction coefficient in gear lubrication model is discussed.The 4-5 order variable step Runge-Kutta method is used to carry out numerical simulation to study the gear vibration characteristics changes caused by the changes of tooth surface micro-morphology and to verify by experiments.

Involute gear is the main gear, and its meshing process is roughly the same.In order to simplify the analysis process, FZG gluing experiment is used to analyze the friction behavior of A-gear in detail.This type of gear achieves a large relative slip rate through modification, and its friction excitation is obvious, at the same time, it accelerates the destruction of the tooth surface, which is conducive to quickly verify the influence of the change of friction characteristics caused by the Micro-changes of the tooth surface on the dynamic characteristics.Figure shows the gear and experimental bench model under study.