Study of a mini-ultrasonic motor with square metal bar and piezoelectric plate hybrid

A new mini-ultrasonic motor with a metal bar and piezoelectric plate hybrid as a stator has been studied. Four piezoelectric plates are bonded to four sides of the metal bar. The metal bar is made of brass and the piezoelectric plates are made of Pb(ZrTi)O-3. The polarization direction is vertical to the piezoelectric plate. Compared with the cylindrical type of motor, the motor with a square cross-section makes polarization more sufficient and the signal wire easier to be welded. In this study, the modal and harmonic analyses of the stator were performed by using the Finite Element Method. The resonance frequency of the motor is about 100 kHz, the no-load revolution is above 6000 rpm and the maximum torque is about 60 mu N m. This new mini-ultrasonic motor has potential applications.