The Research Of Ring-Type Linear Ultrasonic Motor

The ultrasonic motor is a kind of direct driver which is uses the converse piezoelectric effect of the piezoelectricity ceramics, by using transformation and the coupling of each kind of expansion and contraction vibration pattern enlarging the material microscopic distortion by resonate effect and transforming it to macroscopic movement of the rotor or the slide by the friction coupling. The ultrasonic motor displays particular properties like the higher power density, the non-electronmagetic interference, the low speed with big torque, the small start-stop time-constants, the movement without the noise, high holding torque with no current applied and so on. This dissertation is about taking use of the merit of the traveling wave principle, exciting a traveling wave in a ring type stator with two tangential paths, generating the linear movement of the ultrasonic motor.By analyzing the principle of traveling wave, this paper point out that the traveling wave of the rotational motor generates by two same types and frequencies standing wave superimposition, while the traveling wave of the ring-type motor degenerates by two standing wave of extremely approaches in frequencies.Analytical results proves the existence of the two needed bend standing wave which generate traveling wave in the ring-type structure with two linear portions, and also confirms the existence of traveling wave through the harmony response analysis.This paper derives the equation of the particle of the elastomer, obtains the elliptical trace of the notch of the ring-type linear motor, simulates the start term of the motor and educes the theoretical start-time 0.5ms.A prototype motor of the ring-type structure has been manufactured and taken experimental research according to the theoretical analysis results. The ring-type linear ultrasonic motor obtains its maximal velocity 15mm/s with the power of 300V and load of 0.24Kg.