Research on the micro-vibration mechanism of the planetary gear train based on fractal theory

This paper aims to reveal the vibration and tooth surface impact mechanism of the contact surface microstructure of the gear transmission system. Based on the fractal theory, the contact stiffness model of the gear is improved, and a dynamic model considering the micro-deformation of the contact surface is established. The height amplitude and frequency index of the gear surface microstructure jointly determine the type of microstructure deformation. By comparing and analyzing the dynamic response of the system with different fractal dimensions and scaling coefficient, it is found that the microstructure deformation not only reduces the stability of the planetary gear system but also causes a severe impact on the contact tooth surface. When the noise and vibration responses of the planetary gear train gradually stabilize and remain at a low level, the impact characteristics remain at a high level. Only when the fractal dimension is increased to more than 1.6, the impact characteristics of the tooth surface will decrease significantly. This has important theoretical guiding significance for the design and manufacture of high-speed and high-torque electric gear systems.