Vibration Research And Fatigue Analysis Of Harmonic Reducer

As a widely used component in modern machinery,reducer has attracted much attention.While the harmonic reducer,as a rising star,has been widely used because of its advantages,such as small size,large deceleration ratio,small vibration and so on.It is mainly used in the fields of advanced precision mechanical transmission such as missile,submarine,tank,optical instrument precision transmission and high sealing vacuum transmission and so on.This subject takes the 80 harmonic reducer as the research object.On basis of fully understanding the main structure.Vibration research and fatigue analysis are carried out.The main contents are as follows.1)Establish 3D model and verify the interference.Working principle of the harmonic reducer,after analyzing the coordination relation of the whole machine,the precise 3D model designs of the key parts,such as rigid wheel,flexspline,flexible bearing and wave generator,are completed.The data and the assembly of the model are used to verify whether the structure interferes.2)Establish mathematical models and kinematics equations.According to the different stiffness characteristics of harmonic gear drive and other gear transmissions,and considering the backlash influence of wave generator,flexspline and rigid wheel,the mathematical model is established.Then according to the principle of input and output of harmonic reducer and the position relationship of components,the corresponding relative motion equation and the exchange matrix between wave generator and flexspline,flexspline and rigid wheel is established respectively.3)Coupling analysis of the rigid-flexible.The rigid-flexible hybrid model is established by ADAMS software,and the rigid-flexible coupling simulation analysis is carried out on the virtual prototype.Then the variation diagrams of time-history load,the velocity and the displacement of the flexspline with time generated by the meshing of flexible and rigid wheels are obtained.Thus the correctness of the model is verified.4)Vibration and dynamic analysis of the whole machine.According to the error source analysis and the physical model of harmonic transmission,the system dynamics model is established,and the transfer function matrix and frequency response function matrix are obtained.In the software of ANSYS Workbench,the dynamic analysis is carried out,and the deformation cloud diagram,stress diagram,strain diagram and the position of the maximum stress and strain are obtained.Through modal analysis,the first eight modes of the whole machine are obtained,the natural frequency and mode of the structure are determined,and the vibration mode of the whole machine under the specific frequency is obtained.Through harmonic response analysis,the frequency amplitude curve of the whole machine is obtained.The results show that there are obvious resonance at 570 Hz frequency,and the stress and deformation diagrams of the whole machine are obtained at a specific frequency.For the whole machine,flexspline is the most prone to fatigue damage of the parts.5)Fatigue strength analysis on the flexspline.Carry on further detailed analysis to flexspline.According to the smooth cylindrical shell model,the stress analysis of flexspline is carried out,and the normal stress,circumferential normal stress,shear stress and fatigue strength along the busbar are obtained.And then carry on dynamics analysis to flexspline,and the results of harmonic response analysis are in good agreement with the results of the first 8 modes.The flexspline is prone to fatigue failure in the frequency range of 530Hz-540 Hz.By solving the transient dynamic model,it is concluded that the fatigue failure occurs first at the transition between the tooth root of the flexspline and the smooth cylinder.For the fatigue safety factor,the numerical value of the computer analysis is very close to that of the theoretical calculation,which verifies the correctness of the theoretical analysis.Finally,according to the analysis results,some effective suggestions on how to improve the strength of the whole machine are put forward.Through the vibration research and fatigue analysis of the 80 type harmonic reducer,it can better provide the relevant basis for the actual production and contribute to the better performance of the harmonic reducer.