Abstract: According to the principle of NC grinding tooth of spiral bevel gear, the theoretic models of basic grinding tooth parameters and the calculation formula of grinding forces in the physical sense are gotten．The heat distribution ratio is computed by using the thermal model of a single grinding grit, and the heat flux is obtained by applying rectangle heat source．Based on the thermo-elastic-plastic deformation theory, the constitutive relationship of stress-strain field on grinding tooth interface by applying PRANDTL-REUSS method is set up．According to the bilinear isotropic hardening model of gear material, the transient temperature field of a single tooth is simulated by using the 3D finite element model of thermo-mechanical coupling, and the method of small sub-step moving of loads．Many conclusions of the simulation are gotten．Firstly, the place of the highest transient temperature of grinding is located at the center of grinding arc．Secondly, while changing of the conditions, space, time of grinding, and so on, the transient temperature of other points has its corresponding changing rule．By the numerical analysis of comparing test data with simulation ones of thermo-mechanical coupling, the results show that the thermo-mechanical coupling model has relatively high precision. These conclusion provide a foundation for the control of grinding quality of sprial bevel gear.

Key words: 3D model, Grinding tooth, Numerical analysis, Thermo-mechanical coupling