摘要：为揭示预应力对超声电机定子振动特性的影响，准确分析电机的输出性能，对行波旋转型超声电机定子结构在有、无预应力两种状态下进行了模态分析，研究了预应力对超声电机定子振动固有频率和振幅的影响，提出了模态“纯”度的判别标准，分析了预应力对模态混叠的影响。结果表明：预应力增加了超声电机定子振动的固有频率，增大了定子振动的振幅，能够有效抑制电机模态混叠现象。

关键词：预应力；固有频率；振幅；模态混叠
Abstract: For disclosing the effects of pre-pressure on stator vibration to analyse ultrasonic motor output perfotmance more accurately, this paper, aiming to a given ring-type traveling wave ultrasonic motor, studied ultrasonic motor stator mode analyse in double-state with pre-pressure and non-pre-pressure, mainly analysed the affects of pre-pressure on inherent frequency, amplitude of ultrasonic motor stator vibration, and presented mode hallmark differentiate principle to study the affects of prepressure on mode mixing Results shows that pre-pressure can increase ultrasonic motor stator inherent frequency, amplitude and avoid mode mixing availably

Key words: pre-pressure; inherent frequency; amplitude; mode mixing