Optimization Of Flexspline Structure Parameters And Dynamic Simulation For Harmonic Drive

The flexspline, as a critical component of harmonic drive, of which the fatigue strength and meshing performance directly affect the service life and bearing capacity of harmonic drive. Therefore, a reasonable choice of the flexspline structure parameters is very important. This paper takes D120 harmonic drive as the research object. The stress and elastic deformation of flexspline are analyzed based on the finite element method. The transmission performance of harmonic drive is improved by optimizing the cup and tooth profile parameters of flexspline.Firstly, the parameterized model of flexspline contact analysis is established using the shell elements on the basis of harmonic drive theory. The easily fatigue damage location of flexspline is determined by solving the stress field and elastic deformation under load and no-load.Secondly, orthogonal test is applied to study the impact of structural parameters on the maximum stress of flexspline. Further, an optimization model is built to minimize the maximum stress and the optimum parameters of flexspline cup are obtained using zero-order method.Thirdly, the computation model of conjugate tooth profile is derived based on the kinematics of harmonic gear drive, which sets a foundation for the subsequent tooth profile optimization. Meanwhile, the contact state of gear tooth is analyzed according to the spatial distribution of flexspline elastic deformation. The contact line distribution obtained is proved in dynamic simulation.Finally, the entity parametric finite element model of harmonic gear drive is set up, and the gear tooth centrodes and conjugate tooth profile under load and no-load are analyzed by combining with the kinematics of harmonic gear drive. Keep the basic involute profile unchanged on the basis of the optimum structural parameter of flexspline cup. The best parameters of tooth profile are got by amending the addendum coefficient in the manner of approaching the theory conjugate tooth profile. Thus, a new structural model is obtained according to D120 harmonic gear drive. The comparative analysis of new model and original model in flexspline stress and meshing performance is done. The research methods and results not only provide new ideas for structure improvement of harmonic gear drive but also provide reference for further studies on the relationship between flexspline structure and elastic deformation.