Diameter, Twisted Hybrid Ultrasonic Motor

Piezoelectric ultrasonic motor (USM) is a new type of solid-state motor hat has been developed quickly and be used widely in recent years domestic and abroad. Generally, it contains the oscillator (the stator) that causes ultrasonic vibration and the rotor that is connected to the oscillator. USM uses ultrasonic vibration as a power and transmits vibration of stator by the coupling friction between the stator and rotor, and then changes the vibration to continuous rotation or linear displacement, which is used to drive the rotor rotation or move.Ultrasonic motor has characters of simple structure; low noise, high efficiency, large power density, high torque and low speed and can drive large loads directly and so on, which is a breakthrough and effective supplement of traditional motors. The advantages of ultrasonic motors are confirmed in some areas such as aviation, robotics, and other special areas. In recent years, many scholars domestic and abroad try their best to study varieties of ultrasonic motors, which include ring-type ultrasonic motor, longitudinal and torsional composite type ultrasonic motor, mode conversion-type ultrasonic motor and so on.Radial and torsional composite ultrasonic motor has been proposed for the first time in this paper, which has the some advantages, such control easily, high Power output, high torque and positive inversion characteristics consistent, low speed stability. Further, the radial and torsional composite ultrasonic motor is different in structure from the longitudinal and torsional composite ultrasonic motor, which make radial and torsional composite ultrasonic motor could be used widely in some areas,which have special requirements in radial and longitudinal.The radial and torsional composite ultrasonic motor is researched in this paper, based on the previous research work of the radial vibration and torsional vibration, the driving mechanism, theoretical model and solution of resonance frequency and so on, the radial and torsional composite ultrasonic standing wave motor are studied in basic theoretic, which would provide some reference for the further theoretical research and practical application.The context includes several parts as follow:(1) Basis on the existing theoretical, the radial vibration of the piezoelectric ceramic thin disk and the metal thin ring with same thickness are studied and electro-mechanical equivalent circuit are derived. The relationship between fundamental resonance frequency and the geometry is obtained, and the experiments are performed by finite element method.(2) From the torsional vibration equation of the plane shear stress for thin ring and thin disk, the torsional vibration electro-mechanical equivalent circuit of constant thickness piezoelectric ceramic thin ring, thin metal ring and disk with isotropic character in different direct are established, and the resonant frequency are derived from the equivalent circuit. At the same time, torsional vibration resonant frequency of constant thickness piezoelectric ceramic thin ring, thin metal ring and disk with isotropic character in different direct are calculated in theoretical, and the results show that the resonant frequency rises with the inner radius increases and decreases with the outer radius increases. The modal analysis results by computer simulation, and the theoretical calculation and computer simulation are good agreement.(3) The electro-mechanical equivalent circuit of constant thickness piezoelectric ceramic thin disk, thin metal ring with isotropic character in different direct in radial vibration are derived, based on equivalent network cascade theory, the electro-mechanical equivalent circuit of the sandwich piezoelectric ultrasonic motor in radial vibration is established. The resonant frequency equation and analytical expression in radial vibration are derived. The resonance frequency, modal graph and harmonic response graph in some size of the sandwich-type piezoelectric ultrasonic motor system in radial vibration are simulated by finite element method and calculated, it is show that there is good agreement in the results calculated by equivalent network cascade theory with the results of calculation by computer.(4) Applying the front torsional vibration electro-mechanical equivalent circuits of thin disk and ring isotropic in different direction with content thickness and piezoelectric ceramic thin ring, based on equivalent network cascade theory, the electro-mechanical equivalent circuit of the sandwich piezoelectric ultrasonic motor in torsional vibration are established. The resonant frequency equation and analytical expression in torsional vibration are derived from the electro-mechanical equivalent circuit. The resonance frequency, modal graph and harmonic response graph in some size of the sandwich-type piezoelectric ultrasonic motor system in torsional vibration are simulated by finite element method and calculated, the results calculated by equivalent network cascade theory and simulation results by computer are good in agreement.