As an important part of wind turbine, planetary gear transmission system has the advantages of compact structure, strong bearing capacity, and is also one of the mechanisms with the highest failure rate. During the operation of the system, the high temperature of the tooth surface will lead to the tearing of the oil film, which will lead to the failure of the lubricating oil protection, and the sharp rise of local temperature will cause the failure of the transmission system. Therefore, the research on the dynamic temperature field of planetary gear transmission system has important engineering significance for the optimal design of gearbox lubrication mechanism.
In recent years, scholars at home and abroad have carried out a series of studies on the temperature field of planetary gear system. Shi and Liu have studied the temperature distribution law of planetary gear and pointed out that the highest temperature of the tooth surface occurs near the tooth top; Chang et al. analyzed the spatial distribution of gear temperature and flash temperature history on the basis of considering the change of heat source during planetary gear meshing; Bao Heyun and others studied the temperature distribution of the components of the planetary gear system by analyzing the flow field and temperature field inside the planetary gear box; Yin Zhaoming et al. studied the double involute gear by subsection method, and obtained the temperature distribution law that the body temperature is asymmetric along the tooth width direction and the instantaneous temperature field of the driving gear is higher than that of the driven gear; Luo et al. analyzed the factors affecting the friction heat generation of planetary gears, and concluded that the equivalent radius of the meshing point and the thermal load sharing ratio are the important reasons for the temperature change of the planetary gear body; Li et al. analyzed the unsteady temperature field of the gear surface, and obtained the continuous temperature distribution law of the planetary gear surface at any meshing time and at any position; Dobias et al. obtained a series of approximate solutions of temperature field and stress field by establishing numerical modeling algorithm of iterative format for high-speed lubricated helical gears, and studied the influence of friction coefficient on temperature field and the distribution of friction heat flow; Pang Daqian and others discussed the relative growth relationship and growth amount of the transient temperature of the tooth surface, and obtained the rules of the influence of different speeds, different torques and output power on the transient temperature field of the sun gear and the planet gear; Wei Yongqiao and Zhou obtained the transient temperature distribution along the meshing line by analyzing the sensitivity of the contact temperature of the tooth surface to the design parameters and working conditions; Qiao Shuai and others comprehensively considered the influence of the time-varying stiffness of planetary gear and bearing and the flexibility of transmission shaft, and on this basis analyzed the influence of different working conditions on the temperature rise of planetary gear, and obtained the conclusion that the influence of load change on the temperature response of the system is more obvious when the load is at high speed.
To sum up, scholars have carried out a lot of research work on the temperature distribution characteristics of planetary gear transmission system, and have made a series of fruitful research results. However, the research on the temperature field of planetary gear system mostly focuses on the friction heat generation of planetary gears, ignoring the influence of bearing friction heat generation on gear temperature. Therefore, based on the friction heat generation mechanism of planetary gear system, this paper comprehensively considers the influence of bearing gear friction heat generation and bearing gear transmission shaft heat dissipation on the system temperature, and combines the heat transfer theory and finite element thinking to analyze the temperature rise law and temperature distribution of planetary gear transmission system under the change of working conditions.