Modal analysis of harmonic drive reducer based on ANSYS

Modal characteristics are critical indicators for assessing the stability of harmonic reducer and serve as an essential basis for structural optimization. Based on the structure and working principle, the finite element model of harmonic reducer was systematically established and appropriately simplified. According to Block Lanczos method, the natural frequencies and mode shapes of the flexible gear and rigid gear under free boundary conditions were obtained by ANSYS. The single-factor analysis method was employed to investigate the influence of structural parameters of the flexible gear on its natural frequency and torsional stiffness. Results indicate that the natural frequency of the flexible gear increases with the length and wall thickness of the cylindrical section. Although the natural frequency of the flexible gear is lower than that of the rigid gear, it remains higher than the working excitation frequency, thus avoiding resonance. Additionally, the maximum stress in the flexible gear decreases with increasing tube length and wall thickness, which contrasts with the trend observed for torsional stiffness.