# Study on dynamic model of gear system

It is the central task of gear system dynamics to establish accurate dynamic model of gear system. Only by establishing the analysis model of gear system can the dynamic analysis of gear system be carried out effectively. According to the different factors considered among gear pairs, the dynamic models of gear system can be divided into four types: linear time invariant model, linear time-varying model, nonlinear time invariant model and nonlinear time-varying model. At present, the dynamic model of gear system commonly used in research is nonlinear time-varying model. The analysis model considers the time-varying of meshing stiffness and the nonlinear influence caused by the backlash of gear teeth. The model is close to the actual operation state of gear system and relatively accurate.

More and more researchers focus on whether to consider the influence of sliding friction in the dynamic model of gear system. The dynamic model of gear system is established considering the influence of sliding friction.

Considering the sliding friction and time-varying meshing stiffness, a 6 In this paper, the Runge Kutta method is used to solve the gear dynamic model, and the influence of the sliding friction on the dynamic response of the system and the dynamic transmission error in the direction of the meshing line under different micro characteristics of the tooth surface are analyzed. Finally, the simulation model is verified by experiments, and the influence of sliding friction on the dynamic characteristics of gear transmission is determined Sound law. Song et al. Established a 6-DOF dynamic model of gear system. The sliding friction force was introduced into the model as a dynamic excitation. The influence of five different sliding friction models on the dynamic response of gear system was studied by using the gear model song. Based on the 6-DOF dynamic model of gear system established by song et al., this paper mainly studies the change law of gear meshing force in the direction perpendicular to the gear meshing line in the case of considering sliding friction force and not considering sliding friction force.

The dynamic model of gear system is established without considering the sliding friction force. Established 6 The dynamic response signals of the healthy gear and the gear with spalling fault under different working conditions are calculated. The relationship between the tooth spalling fault and the dynamic response of the gear system is obtained by analyzing the dynamic response signals in time domain and frequency domain. At the same time, the edge contact stiffness algorithm is compared with the traditional stiffness algorithm The gear meshing stiffness is calculated to verify the superiority of the algorithm considering the edge contact stiffness.

By establishing a six degree of freedom dynamic model of gear system, Mohamed od et al. Studied the influence of different degrees of gear crack fault on the dynamic response of gear system, and used the method of short-time Fourier transform to diagnose different degrees of crack fault. Four kinds of gear system dynamic models with different degrees of freedom (6 degrees of freedom without friction, 8 degrees of freedom, 6 degrees of freedom with friction force, and 12 degrees of freedom) are established. Through the analysis of the dynamic response of the gear system with different degrees of freedom, the adaptability of the four kinds of gear dynamic models with different degrees of freedom is obtained. 