Study on piezoelectric cylinder micro ultrasonic motor with 1 mm diameter

A tiny ultrasonic motor was constructed by using a cylindrical piezoelectric ceramic as stator. The fabricated tiny motor has a diameter of 1 mm, a length of 5 mm and a/weight of 36 mg. Four electrodes were deposited on the stator's surface and evenly distributed along the circumferential direction. A polarization method was developed for the stator and the space between two adjacent electrodes was carefully designed. By using the bending mode vibration of the stator, the tiny motor shows a performance with 1800 rpm speed and 4 μNm stalled torque and can be bear higher drive voltage until 350 V_pp. With the same technique, fabrication of even smaller motor can be envisioned.