摘  要：分析了双轴承支撑超声电机的加工和装配误差所造成的定、转子接触界面沿圆周方向压力不均衡的现象，它是造成电机转速波动的主要原因之一。在此基础上，提出了一种单轴承支撑附加调心结构的新方案，通过实现接触界面的压力自平衡，来达到提高电机转速稳定性，同时减小体积、减轻质量的目的。实验结果表明，在电机输出力矩、速度等主要性能指标与原结构电机相比没有下降的前提下，新方案电机的空载转速波动率降低了约40%，质量降低约14%，厚度减小了27.3%。
关键词：单支撑超声电机；速度波动率；压力自平衡

Abstract: Firstly, the phenomenon of the pressure imbalance along circumference direction of the interface between the stator and the rotor due to the machining or assembling error was analyzed, which was one of the main reason of the speed fluctuation of the motor which has two bearing structure. Secondly, a scheme using single bearing and self-aligning structure was described and analyzed, which can realize pressure auto-balance of the interface between the stator and the rotor. On the same time, weight and size can be reduced. Finally, the new method was validated by experiment. Compared with the original structure motor, the no-load velocity fluctuation ratio of the new structure motor decreased 40%. Weight is reduced 14%. Size of the main body of the USM is reduced 27.3%. But there is no decreasing in the performance of the new structure motor.
Key words: single bearing ultrasonic motor; speed fluctuation ratio; pressure auto-balance