小型方柱压电陶瓷电机的设计及性能

设计了一种小型方柱弯曲旋转压电超声电机,即摇头式压电陶瓷超声电机.该电机采用带圆孔的金属方柱作为电机的定子部分,并在方柱的4个垂直表面分别粘贴沿厚度方向极化的压电陶瓷片,其外形尺寸小于6 mm×6 mm×10 mm.利用有限元分析软件ANSYS对电机的工作模态进行了模拟计算,得到金属方柱定子的一阶弯曲振动频率为125.5 kHz;并对其工作状态进行了谐响应分析,得到X(Y)向、Z向振幅,由此计算得到定、转子之间的最优接触角,约为24.5°.采用激光多普勒测振仪(Polytec 300-F)测量了电机的振动谱特性,测得一阶弯曲振动发生在129.6 kHz处,并观察到两个节面位于全长的1/4及3/4处,实验与有限元仿真结果基本一致.讨论了不同厚度陶瓷片及金属方柱圆孔孔径大小对电机输出特性的影响,确立了小型方柱电机的尺寸设计标准.

Design and Property of a Square Cylinder Type Piezoelectric Ultrasonic Micromotor

A novel rocking head type piezoelectric ultrasonic motor is designed. A square cylinder of bronze with a hole is used as the stator. 4 piezoelectric plates of PZT- 4 polarized in the thickness direction are bonded to the sides of the bar. The outer size of the motor is less than 6 mm×6 mm×10 mm. Finite element (FEA) of the stator has been made. It is found that the resonant frequency of first bending mode is 125.5 kHz. The working process of the motor is simulated by harmonic analysis, by which the vibration amplitude is calculated. Thus the taper angle of contact surface can be obtained. The Doppler Laser Vibrometer (Polytec 300-F) was used to measure the vibration characteristic of the ultrasonic motor. It shows that the resonant frequency of first bending mode is about 129.6 kHz, which coincides with the FEM result very well. Furthermore, the relationship between the output of piezoelectric motor and different dimensions of the structure are discussed, such as the thickness of piezoelectric ceramic, the diameter of hole in the quadrate bar. That can be useful to design and optimize the piezoelectric ultrasonic micromotor.