The convective heat transfer coefficient of different tooth surfaces and the friction heat flux were identified based on the theory of tribology, heat transfer, and gear meshing theory. A more accurate parametric model of finite element thermal analysis of a single tooth was established by using APDL and the more accurate bulk temperature field of the gear was obtained. The factors that affect the bulk temperature field of gears were also analyzed, and the influence mechanism of each factor was carried out. The results show that high-pressure angle and tooth profile modification cannot only ef...