Buckling analysis of flexspline in harmonic gear reducers

Abstract Harmonic gear reducers are widely used in the field of precision machinery due to their advantages of high transmission accuracy, large reduction ratio, and compact structure. As the core transmission component, the flexspline’s stability directly determines the performance and service life of the reducer. Based on the eigenvalue buckling analysis method, this paper studies the stability of the flexspline under cyclic loads. A three-dimensional finite element model of the flexspline was established, considering material nonlinearity, geometric nonlinearity, and contact boundary conditions comprehensively. Through eigenvalue buckling analysis, the critical buckling loads and buckling morphologies under different modes were obtained, the evolution law of its instability modes was revealed, and the effects of wall thickness on the buckling characteristics were discussed. Under a working torque of 100 N·m, the maximum deformation of the flexspline is 7.2×10 -4 mm, the maximum stress is 123.36 MPa, and the first three-order critical buckling loads are 825.66 MPa, 832.5 MPa, and 846.72 MPa, respectively, all of which are much higher than the material yield limit, indicating that the structure has excellent buckling resistance stability.