| Harmonic gear transmission is a new type of transmission,compared with the worm reducer,planetary reducer and other commonly used domestic high speed ratio reducer,harmonic reducer structure is simpler,smaller volume,larger bearing capacity,and higher transmission accuracy.Widely used in aerospace,radar,medical instruments,robots and other high precision transmission fields.Because of the harmonic drive rely mainly on elastic deformation of flexspline to deliver,so deformation of the flexspline is vital for the harmonic drive performance,this paper takes double circular arc tooth profile without common tangent harmonic reducer as the research object,using parametric programming with MATLAB and finite element method(FEM)with Workbench to explore the harmonic tooth profile parameters and structure parameters on the harmonic drive meshing characteristics and the influence of the flexspline deformation law,based on this,advances the finite element method(FEM)and modification of the harmonic double circular arc tooth profile,and extended to other harmonic tooth profile.Based on changing the radial deformation coefficient,the meshing performance of different tooth profiles and the stress and deformation of flexspline were compared to provide a more complete evaluation system for harmonic tooth profile comparison.1 The composition and working principle of harmonic gear drive and harmonic reducer were explained respectively,and the formula of transmission ratio was deduced by will method for various harmonic drive forms.On the condition of harmonic hypothesis,the deformation equation and the exact rotation Angle relation of the flexspline were derived,and the meshing theory of harmonic drive based on envelope method and improved kinematics method was derived respectively,and the tooth profile equations of each harmonic tooth profile were given.In view of the interference problem of spatial tooth profile meshing,three practice schemes of flexspline with different sections as the main section were proposed,which provide a theoretical basis for the design and modification of tooth profile and the establishment of multi-tooth nonlinear contact finite element model in the following paper.2 Taking CSF-25-80 double circular arc tooth profile without common tangent as an example,the conjugate tooth profile of double circular arc tooth profile was solved,and the conjugate characteristics of double circular arc tooth profile were studied.On this basis,and the meaning and quantitative index of "double conjugate" phenomenon of double circular arc tooth profile were expounded.The influence law of tooth profile parameters on harmonic conjugate characteristics was analyzed,and the influence law of structural parameters on the deformation of the flexible wheel was explored.The advantages and disadvantages of the three repair schemes were analyzed from the meshing state,and on this basis,the influence of structural parameters on the flexspline three-dimensional adjustment was further analyzed.3 Taking the double circular arc tooth profile without common tangent as the research object,the finite element method was used to analyze the finite element radial deformation of the flexspline.After determining the tooth profile parameters of the flexspline,the improved kinematics method was used to design the circular spline tooth profile conjugated with the flexspline by assuming the linear radial deformation and the finite element radial deformation respectively.Based on the radial deformation of linear hypothesis and finite element method,the flexspline tooth profile was modified in three dimensions,and the stress of flexspline was compared and analyzed between the linear pseudo design and finite element method.The finite element method was used to improve the accuracy and practicability of the design and modification of the harmonic double circular arc tooth profile,which provides some reference for the design and modification of the actual harmonic tooth profile.4 Taking the common tangent double arc tooth profile,the double arc tooth profile without common tangent and the involute tooth profile as the research objects,the true deformation of the flexspline is obtained by finite element,and on this basis,each tooth profile is designed and Modification,respectively explores the conjugate characteristics,motion trajectory and stress deformation of each harmonic tooth profile when the radial deformation changes,and compare the advantages and disadvantages of each tooth profile in terms of meshing performance and stress deformation.It provides a more complete theoretical basis for the evaluation and selection of the harmonic drive tooth profile. |
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