Design And Optimization Of Double-point Meshing Combined Tooth Profile Harmonic Drive

The harmonic drive,which relies on the elastic deformation of the flexspline,solves the contradictory problem between the large transmission ratio and the structure size,and has become the focus of attention in the field of aerospace exploration,artificial intelligence and military field.The tooth profile directly affects the load-bearing capacity,transmission accuracy and transmission efficiency of the harmonic reducer.Involute gears have many advantages such as constant transmission ratio,excellent stability,and separability of transmission.However,when the tooth profile is meshed,the convex tooth profile is conjugated with the convex tooth profile,and there is only a single point of meshing,which makes the tooth profile contact strength lower;When the arc gear is meshed,the concave tooth profile and the convex tooth profile are in contact,the overall radius of curvature is large,and the contact strength is large,but the arc tooth profile is very sensitive to the center distance,and the deviation of the center distance during manufacturing and installation will produce changes in the tooth center distance.Amount,resulting in poor contact,causing damage to the gear teeth.Therefore,the research of the new type of tooth profile harmonic reducer is particularly important.This paper proposes a double-point meshing combined tooth profile harmonic drive,which combines the arc gear with the traditional combined gear,so the gear not only inherits the meshing advantages of the combined gear,but also inherits the double arc The advantages of gear meshing,its comprehensive meshing performance is superior.The main research contents are as follows:(1)Structural design of double-point fitting combined tooth profile harmonic reducer.The important structural parameters of the three major components of this type of reducer are determined.In addition,the design method of the wave generator is researched,and the radial deformation of the wave generator with different profile curves is compared and analyzed.(2)Harmonic gear meshing envelope theory and tooth profile design method.Based on the envelope theory,when the contour of the wave generator is elliptical,after giving the tooth profile of flexspline,the flexspline deformation equation is established,the general formula of the conjugate tooth profile is derived,and the circular spline tooth profile expression is given;Establish a method for solving the rigid tooth profile and numerically solve the circular spline tooth profile in matlab;Taking the double-arc tooth profile and the involute tooth profile as examples,the numerical solution of the tooth profile curve wasperformed,and the tooth profile parameters were optimized by observing the effect of the tooth profile structure parameters on the conjugate area,and verifies the tooth profile solution correctness.(3)Double-point meshing combined tooth profile design.Based on the study of the tangential double arc tooth profile,the arc gear is combined with the traditional involute gear,and an combined tooth profile with double point meshing in the working process is designed.Conjugate areas of the tooth profile,arc profile,male tangent double arc profile and double-point meshing combined tooth profile were compared,which proved that the double-point meshing combined tooth profile has the conjugate area,has a large meshing angle,two-point conjugation,and strong bearing capacity.Then,the least square method is used to fit the curve of the circular spline.It is verified that there is no interference phenomenon in the tooth profile meshing process,which further proves the feasibility of the double point meshing involute tooth profile,which can be used as a good harmonic transmission tooth Profile for designers to choose.(4)Finite element analysis of bowler-type flexspline.The effects of length-diameter ratio,bottom chamfering,barrel wall thickness and ring gear wall thickness on stress distribution in key areas were studied.Finally,taking the maximum equivalent stress on the flexspline as the optimization goal,an orthogonal experiment was designed to optimize the structural parameters of the flexspline.