Study On Longitudinal-torsional Mode Conversion Ultrasonic Motor With Diagonal Slits

Ultrasonic motor(USM)is a new type of micro motor developed rapidly after 80 time in twentieth Century,the basic principle of USM is using the inverse piezoelectric effect of the piezoelectric material to excite the high frequency and micro amplitude vibration of the elastomer,then pass energy through friction.It has unique advantages compared with the traditional motor.After thirty years of development,ultrasonic motor has been widely used in various industries,such as industrial control,precision instruments,aerospace,automotive and other fields.At present,many countries attach great importance to USM,invested a lot of manpower and material resources.The mode conversion ultrasonic motor has been widely concerned due to its power output torque,simple structure,easy assembly and other advantages,a lot of research has been done at home and abroad.This paper designs a longitudinal-torsional mode conversion type ultrasonic motor with diagonal slits,the stator vibration theory of large diameter mode conversion ultrasonic motor is introduced in detail and analyze the influence of size parameters of mode conversion type ultrasonic motor with diagonal slits on motor performance.The main contents are as follows:(1)The basic concept,development history,features and application of ultrasonic motor are described in detail,according to the existing problems of the ultrasonic motor,the contents of this paper were determined.(2)Introducing the basic knowledge of piezoelectric ceramics and deducing the mode conversion mechanism and the motor drive mechanism of the ultrasonic motor.Analyzing the driving trajectory of the motor and the selecting the driving trajectory of the motor.(3)Introducing the vibration equation of cylindrical shell transducer,deducing the frequency equation of the ultrasonic motor stator by the equivalent circuit method.Doing the sensitivity analysis of the main parameters of the motor with the finite element software and the degree of influence of the parameters to the frequency and amplitude of the motor is obtained.(4)Introducing the structure of the motor in detail and making the optimization analysis of the parameters according to the sensitivity analysis then get the optimal motor parameters to make the design optimization.(5)Making the finite element analysis of the designed motor and get the vibration amplitude of the excited vibration frequency of the motor to do reference for future experiments.