Design Of Short Harmonic Drive With Double-circular-arc Tooth Profile

In this paper, according to the engagement theory of harmonic drive, and combining with the experience of designing involute tooth profile, the short harmonic drive with double-circular-arc tooth profile (DCATP) was designed. and then the structure of its flexspline was analyzed and optimized with FEA (finite element analysis). Finally, the prototype of this harmonic drive is manufactured. The main work done in this paper is briefly stated as follows:(1) The DCATP of the flexspline was designed based on the engagement principle of harmonic gear and its special transmission characteristics, the tooth profile of circular spline which is conjugate with the tooth profile of the flexspline was designed based on the envelope theory.(2) The key components of the harmonic drive were designed in details, their 3d models were established and assembled by Solidworks, the meshing performance is analyzed under the condition of static model, include the distributing disciplinarian of the gear, backlash and meshing characteristics.(3) The static analysis of the flexspline structure is carried out, calculating its fatigue strength, and checking the stability of its structure.(4) Stress and strain of the flexspline was analyzed through the software ANSYS when it was loaded with wave generator, making sure its deformation is within the reasonable range of the design, and predicting its easily damage area. Taking the stress of the flexspline as objective function to optimize its structure through multiple tests about its important parameters.(5) In order to verify the correctness of the design, the harmonic drive with DCATP was machined, the tooth of the flexspline was machined in Hero hobbing machine, the tooth of the circular spline was machined in gear shaping machine made in china. As can be seen by the above work that the harmonic gear with DCATP has better engagement performance, based on this, and combined with the optimal design of the short flexspline structure, the design of the short harmonic reducer with DCATP is realized, finally, the trial production of harmonic reducer (25-50) is finished.