1. Simulation method validation
In order to verify the simulation model, the minimum oil film thickness is far less than the root mean square of tooth surface roughness and the coefficient of viscous pressure α Take 2.6 × As shown in Figure 1, the test data include the amount of wear at the root of two adjacent teeth. The difference between them is mainly caused by manufacturing and installation errors, while the influence of these factors is ignored in the simulation model. In the early stage of wear, the wear change rate of the test results is slightly higher than that of the simulation results, which is mainly due to the absence of additives in the test oil. As time goes on, the wear rate of simulation results is gradually consistent with the experimental data, which verifies the effectiveness and accuracy of the proposed model.
2. Analysis of simulation results
According to the load distribution model, the load distribution coefficient of the meshing tooth surface changes with the increase of the number of wear cycles. Fig. 2 shows the change law of the load distribution coefficient of the meshing tooth surface with the number of meshing cycles. It can be seen from Fig. 2 that the wear does not change the load of the single tooth meshing zone, but only changes the load distribution of the double tooth meshing zone, For the driving gear, the load in the double tooth meshing zone near the tooth root decreases gradually with the increase of wear depth, while the load in the double tooth meshing zone on the other side is opposite; For the driven gear, the load of the double tooth meshing zone near the top of the tooth decreases gradually with the increase of the wear depth, while the load of the double tooth meshing zone on the other side is on the contrary.
It can be seen from the formula that, for the meshing gear pair under the steady-state condition, the tooth surface wear coefficient changes with the change of meshing position and tooth surface load distribution. As shown in Figure 3, the wear coefficient decreases from the meshing point near the root of the driving gear to its tooth top. In the single tooth meshing area, the wear coefficient suddenly increases, mainly due to the increase of load on the tooth. With the increase of wear times, the wear coefficient at the initial meshing position decreases gradually, and the wear coefficient at the alternate position of double tooth meshing area and single tooth meshing area increases gradually, which is the same as the change law of load distribution coefficient at corresponding position in Figure 2.
Figure 4 shows the cumulative wear depth of the master-slave gears at different meshing positions. It can be seen from the figure that the most serious wear occurs at the root of the driving gear (see Fig. 4 (a)), and the maximum wear occurs at the top of the driven gear (see Fig. 4 (b)), which is mainly due to the large wear coefficient, high contact pressure and large sliding ratio at the meshing position. The wear of gear pair near the pitch line is almost zero, which is mainly due to the fact that only rolling occurs there. It is worth noting that, due to the alternation of single tooth meshing and double tooth meshing, the tooth surface load changes suddenly, which makes the tooth surface wear depth change suddenly at time a. these conclusions are consistent with the experimental results.
(b) Driven gear