环形行波超声波电机面接触分析及转子结构优化设计

考虑转子的柔性变形，建立了环形行波超声波电机定转子三维面接触模型，分析了定子的振动、定转子的法向接触以及切向摩擦，研究了定转子间的面接触特性及电机的转矩-转速特性。结果显示：由于转子的柔性变形，定转子间的接触区域形状是不规则的，接触压力沿径向分布是不均匀的。通过将样机转矩-转速特性的理论计算值与试验测量值进行对比，验证了三维面接触模型。在此基础上，基于三维面接触模型，分析柔性转子结构参数变化对定转子最大接触压力及电机转矩-转速特性的影响，根据分析结果对转子结构进行优化，实现了定转子间的最大接触压力明显下降，并使电机的转矩-转速特性得以明显提升。

Surface Contact Analysis of Ring Type Traveling Wave Ultrasonic Motor and Optimization of the Rotor Structure

Taking the flexibility of rotor into account, a three-dimensional surface contact model of ring type traveling wave ultrasonic motors is developed. The stator vibration, the normal contact and the tangential friction between the stator and rotor are analyzed, and the surface contact mechanism between the stator and rotor and the torque-speed characteristics of the motor are investigated. The results show that owing to the flexibility of the rotor, the shape of contact area between the stator and the rotor is irregular and the contact pressure distribution along the radial direction is inhomogeneous. The three-dimensional surface contact model is validated by comparing the calculated torque-speed characteristics with the measured values of the prototype motor. Based on the three-dimensional surface contact model, the influences of the structural parameters of the flexible rotor on the maximum contact pressure and the torque-speed characteristics of the motor are analyzed. The structure of the rotor is optimized according to the analysis results, which achieves a significant reduction in the maximum contact pressure as well as an obvious improvement of torque-speed characteristics of the motor.