过载下超声电机设计及预压力分析

Design and Pre-pressure Analysis Under Overload for Ultrasonic Motor

由于超声电机的预压力易受外界干扰而发生变化,为其在受过载时预压力保持基本恒定,基于PMR40型超声电机,设计了一款开槽碟形弹簧(碟簧),作为缓冲件来改进电机结构,并建立了整机冲击动力学模型。在最高冲击加速度为1000g^5000g轴向过载下,碟簧对电机预压力的影响进行分析。结果表明:电机在受到最高加速度在1000g以下时,碟簧对预压力维持作用非常明显,无碟簧和含碟簧结构电机预压力变化率分别为28.1%和10.0%;受冲击加速度在2000g以上时,碟簧对电机预压力的维持能力有所下降,但其缓冲作用可降低预压力变化,从而使电机工作相对稳定。该研究对适用于过载下超声电机的设计具有指导意义。

The pre-pressure of the ultrasonic motor will be easily changed by external influence,which affects the stability of its operation.For the application of ultrasonic motor under overload,a new structure must be designed to keep its pre-pressure basically constant.Based on the PMR40 type ultrasonic motor,a slotted disc spring is designed in this work as a buffer to improve the structure of the motor.The impact dynamics model of the whole motor is established under maximal impact acceleration of 1000 g^5000 g to analyze the influences of the disc spring on the pre-pressure of the motor.The results indicated that the disc spring had obvious maintenance impact on the pre-pressure of the motor when the maximal axial acceleration is under 1000 g.The variation rate of pre-pressure for the motors without and with the disc spring were 28.1% and 10.0% respectively.While under high overload condition(maximal acceleration≥2000 g),the ability of the disc spring to maintain the pre-pressure of the motor is decreased,but its buffering effect can reduce the change of pre-pressure relatively,so as to maintain the stability of the motor.This work is of important guiding significance for the design of ultrasonic motors suitable for overload.