Ease-off拓扑修形准双曲面齿轮齿面多目标优化设计方法

A design approach of multi-objective tooth optimization for hypoid gears with ease-off topological modification is proposed to improve comprehensive meshing performances of automobile drive axle. Firstly, the modified pinion is represented by a sum of two vector functions that determine the conjugate tooth of gear and the pinion normal ease-off surfaces, respectively, and are expressed by both predesigned transmission error function and tooth profile modification curves. Secondly, based on tooth contact analysis (TCA), loaded tooth contact analysis (LTCA) and the latest friction theory of gear, the bearing deformations, sliding velocity, distribution of loads and local friction coefficient of the discrete points on contact line of gears are obtained, and the instantaneous meshing efficiency and Block flash temperature are further determined. Thirdly, the best ease-off surfaces are obtained by solving a multi-objective optimization problem with minimal amplitude of loaded transmission error (ALTE), minimal instantaneous flash temperature and maximal average meshing efficiency. Moreover, the distribution of sliding velocity, the radius of curvature on tooth, and the influences of contact ratio on meshing performances are explored. Numerical results show that the best ease-off modification has enough parabola transmission errors at the meshing start and the meshing end, which can effectively reduce the sensitivity of installation error and ALTE. In addition, profile modification and small inclination of contact path contribute to a greater contact ratio, and the loads at top and root concentrate near the pitch line, while the sliding speed near the pitch line is smaller, as a result the meshing efficiency increases and the flash temperature decreases. However, when the tooth surface mismatch is too large, the loads and friction power consumption will increase, and the meshing efficiency will decrease.