As shown in the figure, the three-dimensional nephogram of contact stress of the 0 # unmodified, 1 # optimized plan and 9 # optimized plan. The maximum contact stress before modification is as high as 553.412MPa, while the maximum contact stress after modification by No. 1 and No. 9 optimization schemes is 546.239MPa and 533.574MPa respectively, which is 7.173MPa and 19.838MPa lower than that without modification.
For the No. 1 optimization scheme, although the contact stress is slightly increased in the middle of the gear tooth, it will not affect the overall life of the helical gear, because the hardness in the middle of the gear tooth is relatively high and the bearing capacity is stronger; At the same time, the stress value at the root and top of the gear tooth has also decreased to a great extent, which has the advantage of reducing the degree of eccentric load of the helical gear tooth, preventing stress concentration, and helping to improve the bearing capacity and service life of the helical gear. For the No. 9 optimization scheme, although the distribution of the contact stress on the tooth surface has not changed significantly, the stress mutation phenomenon (the red part of the contact stress has serrated fluctuation before the modification) disappears.