The optimal modification scheme of the involute of the long tooth profile is the modification amount of the driving wheel 5 μ m. Modification quantity of driven wheel 4 μ m。 Figure 1 shows the time varying meshing force curves before and after the helical gear pair is optimized and modified by the involute of the long tooth profile tooth top at different speeds. This modification scheme effectively improves the meshing impact of helical gears, and the time-varying meshing force of helical gears under all working conditions is significantly reduced, and the peak meshing force under low, medium and high speed working conditions is only 19876.426N, 51253.637N, 98132.328N, reduced by 122.687N, 1540.64N, 2348.992N.
Figure 2 shows the time-varying meshing stiffness curve of the helical gear pair before and after the optimization and modification of the tooth top involute of the long tooth profile. Obviously, this scheme reduces the fluctuation range while reducing the time-varying meshing stiffness of the helical gear pair. Its peak value is only 4.38 × 10 ^ 8N/m, with a decrease of 14.1%; The fluctuation range is reduced to 3.67 × 10^8N/m~4.38 × 10^8N/m。
In general, the dynamic excitation of the helical gear pair of the reduction box of an electric vehicle after the optimization and modification of the involute of the tooth top of the long tooth profile has decreased significantly. Although the meshing impact of the helical gear under the low speed condition has not been completely eliminated, it has significantly improved compared with the unmodified one, and the vibration of the helical gear pair has been greatly reduced.