In order to study the influence of different applied torques on the vibration characteristics of gear pair and keep other parameters unchanged, the two excitation and vibration responses of gear pair with applied torques of 1t, 0.5T and 0.25t were analyzed respectively. The meshing stiffness curve of gear pair under different applied torque is shown in Fig. 1.

It can be seen that under the same torque, with the increase of tooth thickness deviation, the single tooth meshing stiffness of gear pair decreases, which is consistent with the previous conclusion; Under the same tooth thickness deviation, the single tooth meshing stiffness of the gear pair decreases with the decrease of the applied torque. This phenomenon is mainly caused by the nonlinear change of contact deformation with the load. When the applied torque is small, the total meshing force of the gear pair is also small, and the two gears are just in contact. At this time, the local contact deformation is more likely to occur, and the contact stiffness caused by the contact deformation is smaller, which leads to the decrease of meshing stiffness, which is consistent with the conclusion.

The transmission error of gear pair under different action torque is shown in Figure 2.

It can be seen that under the same torque, with the increase of tooth thickness deviation, the transmission error of gear pair increases, which is consistent with the previous conclusion; Under the same tooth thickness deviation, the transmission error decreases with the decrease of applied torque.

The dynamic meshing forces of gear pairs under different applied torques are shown in Fig. 3-5.

It can be found that with the increase of tooth thickness deviation, the dynamic meshing force fluctuation and system vibration increase under the same torque, which is consistent with the previous conclusion; Under the same tooth thickness deviation, with the decrease of applied torque, the fluctuation of dynamic meshing force decreases obviously, the vibration of gear pair decreases, and the sensitivity of gear pair vibration characteristics to tooth thickness deviation decreases.