For the established dynamic model of gear system, the influence of sliding friction on tooth surface is considered in the model. Therefore, the Coulomb friction model μ I (T) with time-varying friction coefficient is introduced

In the formula, μ AVG is the average friction coefficient, which is related to tooth surface roughness, lubrication condition and relative sliding speed. When the gear is rotated and engaged, the friction coefficient will change with time. The sliding friction force of gear can be calculated by the formula, and the influence of sliding friction is introduced into the dynamic model of gear system.

Establishing the analysis model of gear system is the central task of gear system dynamics. Only by establishing the dynamic model of gear system can the dynamic analysis of gear system be carried out effectively. This paper introduces the nonlinear gear dynamic model considering the influence of gear sliding friction, and describes the process of establishing the gear dynamic model in detail. In addition, the calculation method of meshing stiffness of healthy gear and pitting fault gear is mainly introduced, which provides a theoretical basis for calculating the meshing stiffness of different gear states. At the same time, it also briefly describes the calculation process of gear dynamic model The Coulomb friction model with time-varying friction coefficient provides a method for introducing the influence of tooth surface friction into gear dynamic model.