Design, analysis, and optimization of a strain wave gear with a novel tooth profile

In this study, an optimization process was designed for a strain wave gear (SWG) through finite element analysis (FEA) to improve its performance. Two optimization steps are executed in this process. In the first optimization step, a novel two-dimensional (2D) tooth profile is obtained using a double Bezier curve with a common tangent line profile (DBCCTLP), and the mathematical model of this profile is derived. Subsequently, the obtained tooth profile is optimized through 2D FEA based on the torsional stiffness and number of engaged teeth. A three-dimensional (3D) model of an SWG is subsequently established to explore its 3D meshing performance through FEA and optimize the parameters of its flexible spline (FS). In the second optimization step, 3D FEA is conducted to predict the torsional stiffness, hysteresis loss, and stress of the SWG using the DBCCTLP-based optimum tooth profile. The optimum structural design parameters for a 3D FS cup were determined through 3D FEA and optimization. Finally, the transmission error and cyclic stress for the initial and optimum SWG design were successfully simulated and compared.