Study On Wear Failure Mechanism Of Harmonic Reducer Of Industrial Robot

With the coming of the era of "Made in China 2025" and "Industrial 4.0",Chongqing needs to break through the technical bottleneck of key parts such as precision reducer of robots and revitalize the development of local robotic enterprises in the face of the huge application demand of industrial robots in the fields of automobile,machinery,electronics,national defense and military industry.Aiming at the problem that the precision of the harmonic reducer of industrial robot decreases gradually due to long-term operation under complex working conditions,this paper first determines the structural design parameters of the harmonic reducer equipped with J6 joint of a six-degree-of-freedom industrial robot,and establishes a three-dimensional finite element simulation model.Then,according to the input speed,load and lubrication of the harmonic reducer,the lubrication modes under different working conditions are deduced.At the same time,the fatigue wear life model of thin-walled bearings in harmonic reducer about the failure of flexible rings under working load is obtained.Finally,the accumulative wear accumulative precision failure model of harmonic reducer’s main contact pairs is established,and the variation law of wear on harmonic transmission efficiency,backlash and meshing transmission is analyzed,and the harmony is explored.Failure mechanism of precision degradation caused by wear of wave reducer.The research on the mechanism of the deterioration of harmonic transmission accuracy caused by the wear accumulation of the main contact pairs of harmonic reducer provides important reference for prolonging the service life of industrial robots,accuracy compensation and design of harmonic reducer,and has important economic value for promoting intelligent manufacturing and industrial transformation in Chongqing.The main research work of this paper is as follows:1)According to the meshing principle of harmonic drive,the meshing parameters of flexible wheel-rigid wheel are designed and selected.The main structural parameters of flexible wheel,rigid wheel and wave generator in harmonic reducer are determined.The meshing interference analysis of harmonic involute gear is carried out.The accuracy of the main structural parameters of harmonic reducer is proved by finite element assembly analysis and meshing simulation analysis.2)The wear failure mechanism of friction contact pairs of harmonic reducer under different lubrication conditions is studied.The contact fatigue wear model of contact pairs under elastohydrodynamic lubrication,boundary lubrication and adhesive wear model of contact pairs under mixed lubrication are deduced and studied.The contact simulation analysis of friction contact pairs of flexible wheel-wave generator and flexible wheel-rigid wheel elastic contact pairs under different lubrication conditions is carried out.3)Assuming that the maximum assembly deformation of Thin-walled bearing inner ring is unknown,based on the theory of flexible ring and thin-walled ring,the assembly deformation of Thin-walled bearing inner ring and cam,the elastic deformation of rolling body and flexible inner and outer ring,and the equivalent loading deformation of Thin-walled bearing outer ring are studied.The deformation compatibility equation,force balance equation and multi-body assembly contact finite element model of Thin-walled bearing are established.Finally,the fatigue wear life model of thin-walled bearings based on load distribution is obtained.4)The influence factors and action rules of wear on the backlash,transmission efficiency and meshing transmission of harmonic reducer are studied,and the degradation model of harmonic transmission accuracy failure is established by using the wear cumulants of the contact pairs inside the harmonic reducer under the condition of the overturning material test operation of the robot.Finally,the paper summarizes the work of this paper and looks forward to the next research direction.