1.Calculate the S-N curve of gear

The required contact strength is calculated according to ISO / TS 6336-2.

Since it is a life calculation, the safety factor shmin = 1 and the life factor ZnT = 1 are taken to obtain the S-N curve in Fig. 1

2.Calculation of contact life of gear

According to ISO / TS 6336-2, the formula of gear contact strength is as follows:

The contact stress and life of the gear can be obtained by calculation. The corresponding S-N curve is shown in Fig. 2.

The life under load spectrum is calculated as follows:

From the life calculation of single working condition and load spectrum, the instantaneous peak load has a great influence on the contact life of gear. Even under the normal working load, the contact life can meet the design requirements, and there is a high safety margin. The instantaneous peak load will greatly reduce the contact life of the gear.