Reducing the fluctuation of static transmission error is a well-known tooth profile modification criterion, but in practice, there are not only indexes to measure the fluctuation, such as CHTE and PPTE. In the variable naming rules, CHTE represents the combination of harmonic amplitude of static transfer error, see formula; PPTE represents the peak value of static transfer error.
Taking gear pair 3 as an example, figure 1 shows the change of CHTE and PPTE with the modification amount of tooth profile. The abscissa of the minimum point of CHTE and PPTE is the same when there is no tooth direction drum trimming, as shown in Figure 1 (a). The abscissa of the minimum value of CHTE is greater than that of PPTE when there is tooth direction drum trimming, as shown in Fig. 1 (b). The results show that the optimal profile modification with the minimum of CHTE or PPTE as the objective is the same without profile modification, and the optimal profile modification with the minimum of CHTE as the objective is greater than that with the minimum of PPTE as the objective.
Figure 2 shows the dynamic load coefficient of gear pair 3 under different tooth profile modification. Figure 2 (a) shows the result of long modification and Figure 2 (b) shows the result of medium modification. Although the modification effect of medium modification is not sensitive to the modification amount, the dynamic load coefficient of gear system with CHTE as profile modification index is smaller. Figure 3 is the static transmission error curve of gear pair 3 under the condition of long profile modification. In Figure 3 (a), CHTE is taken as the profile modification index, and in Figure 3 (b), PPTE is taken as the profile modification index. It can be seen that although the fluctuation amplitude in Fig. 3 (b) is smaller, the sudden change is more obvious when the single and double teeth alternate, so the impact on the system is greater.