According to the established contact fatigue finite element simulation model of hypoid gear transmission system, the finite element simulation software ANSYS Workbench is used for numerical calculation, and the equivalent stress distribution of hypoid gear transmission system is obtained, as shown in Figure 1.

It can be seen from Figure 1 that under the working conditions of rotating speed 2750 R / min and resistance moment 2000 nm, the maximum equivalent stress of meshing tooth pair of hypoid gear is mainly distributed in and near the arc contact surface of large and small hypoid gear, and the maximum equivalent stress at the arc contact surface of hypoid gear is 645.93 MPa, The safety factor of the maximum equivalent stress corresponding to the yield strength of hypoid gear material 1292 MPa is 1 292 / 645.93 = 2.000 22 ＞ 2, which meets the transmission requirements of hypoid gear transmission system under static and dynamic actual road conditions.

The equivalent elastic strain distribution of hypoid gear transmission system obtained by simulation calculation is shown in Figure 2.

It can be seen from Figure 2 that under the working conditions of rotating speed 2750 R / min and resistance moment 2000 nm, the maximum equivalent elastic strain of meshing tooth pair of hypoid gear is mainly distributed in and near the arc contact surface of large and small hypoid gear, which is basically consistent with the change trend and distribution of equivalent stress. The maximum equivalent elastic strain of the arc contact surface of hypoid gear is 0.003 229 7, and the equivalent elastic strain is small as a whole, which can be basically ignored. The hypoid gear transmission system designed under this condition can meet the requirements of strength and stiffness of the gear transmission system.

The equivalent stress distribution of contact tooth surface of large and small hypoid gears in hypoid gear transmission system is obtained by simulation calculation, as shown in Figure 3.

It can be seen from Figure 3 that under the working conditions of rotating speed 2750 R / min and resistance moment 2000 nm, there are differences in the magnitude and maximum distribution of the equivalent stress on the contact tooth surface of large and small hypoid gears in the meshing tooth pair of hypoid gears; The maximum equivalent stresses on the contact tooth surfaces of large and small hypoid gears are 217.96 MPa and 183.49 MPa respectively. The reasons for the above phenomena are that the curved tooth surfaces of large and small hypoid gears are complex, the contact forms and sizes of contact surfaces at different positions are different, and the bearing capacity of the curved surface of hypoid gears is large.

In order to calculate the fatigue life of hypoid gear transmission system under the above conditions, the hypoid gear material is tested to obtain the P-S-N curve of hypoid gear material, as shown in Fig. 4.

It can be seen from Figure 4 that the S-N curves of hypoid gear materials are different under different survival rates P, but the change trend of the corresponding curves is basically the same; With the increase of survival rate P, S-N decreased gradually. In this study, based on the S-N curve of hypoid gear material corresponding to survival rate P = 95% and the contact characteristic parameters analyzed above as boundary conditions, the fatigue life of meshing tooth pair of hypoid gear is obtained by simulation calculation, as shown in Fig. 5.

It can be seen from Fig. 5 that under the conditions of rotating speed 2750 R / min, resistance moment 2000 nm, P = 95% corresponding S-N curve of hypoid gear material, the minimum fatigue life of hypoid gear meshing tooth pair is 2.241 × 106 times, max. 6.459 3 × 107 times; The fatigue life of hypoid gear is the smallest where the contact stress is the largest. The reason for the above phenomenon is that the greater the load, the greater the damage of the gear at the corresponding part and the smaller the fatigue life. Therefore, it is necessary to avoid concentrated load in the design process. It should also be well lubricated in actual operation, and the gear should be repaired and treated in time in case of damage.

To sum up, the contact fatigue finite element simulation analysis of hypoid gear transmission system shows that the maximum equivalent stress and equivalent elastic strain of hypoid gear meshing tooth pair are mainly distributed in and near the arc contact surface of large and small hypoid gears; The maximum equivalent stress meets the transmission requirements of hypoid gear transmission system under static and dynamic actual road conditions, and the equivalent elastic strain meets the requirements of strength and stiffness of gear transmission system; There are differences in the magnitude and maximum distribution of equivalent stress on the contact tooth surface of different hypoid gears; Under different survival rates P, the S-N curves of hypoid gear materials are different, and the variation trend of the curves is basically the same; The fatigue life of hypoid gear is the smallest where the contact stress is the largest.