| Harmonic drive has many advantages,such as simple structure,large transmission ratio,more meshing teeth and high transmission accuracy.It is widely used in robotic joints,aerospace and other fields.Wave generator is one of the three components of harmonic drive,which has an important influence on meshing performance and flexspline strength of harmonic drive.The flexible bearing of the existing harmonic wave generator with flexible bearing and cam combination is the weak part in the harmonic drive,which directly determines the service life of the harmonic drive,and is difficult to manufacture and high in production cost.Therefore,exploring the new structure of harmonic wave generator,perfecting its design theory and analyzing the stress of wave generator are of great significance for improving the service life of harmonic drive and reducing the manufacturing cost of harmonic drive.In this paper,a new type of wave generator for harmonic drive is presented,which is integrated into the inner wall of flexspline and cam and is supported by full cylindrical roller bearings.Focusing on its design theory research,the parametric optimization and stress analysis of wave generator and flexspline are carried out,and the finite element analysis of a new type of harmonic drive based on integrated design of cylindrical roller wave generator is carried out.The main research contents are as follows:(1)Structural design of a new integrated cylindrical roller wave generator.The working principle of wave generator is studied.According to the circumferential clearance condition of full cylindrical roller bearing,the basic structural parameters of cylindrical roller wave generator are determined,and the theoretical design method of the cam profile of wave generator is studied.(2)Optimum design of flexspline and wave generator parameters.A simplified parametric assembly model of flexspline and wave generator is established by UG.The effect of main parameters on the deformation and stress of flexspline is discussed.The response surface method is used to optimize the parameters of the flexispline and wave generator,The strength analysis of the optimized flexspline is also carried out.(3)A finite length elastic contact model is established.The finite length elastic contact model is established,and the numerical solution method is used to compile the matlab solver program.According to the working criterion of harmonic drive,the equivalent load of the new cylindrical roller wave generator and the maximum load of the roller are determined.The influence of modification mode and parameters on contact stress of cylindrical roller with flexspline and cam is discussed.The modification curve and its parameters of cylindrical roller suitable for wave generator in this paper are determined.(4)Finite element analysis of a new harmonic drive with integrated cylindrical roller wave generator.The stress and deformation distribution of the flexspline under no-load and load under the action of the new integrated cylindrical roller wave generator are obtained by finite element simulation.The effect of wave generator combined with cam and flexible bearing on flexspline is compared and analyzed.The stress distribution of roller and cam under load and inclined condition is analyzed.The stiffness curves of the cylindrical roller wave generator and flexspline simplified model are obtained.Finally,modal analysis of the flexspline is carried out. |
