Piezo Sonic's PSM60N-ET ultrasonic motor. Motor (front) and driver (back)

Piezo Sonic (Setagaya-ku, Tokyo) has released a high-torque ultrasonic motor, the PSM60N. The ultrasonic motor rotates by minute vibrations and frictional force. Since it does not use coils and magnets, it can be used in high magnetic field environments such as magnetic resonance tomography (MRI) systems.The company's ultrasonic motor uses a piezoelectric element to vibrate a ring with a comb-shaped slit. When the rotor (rotating body) is brought into contact with the ring, the vibration of the teeth is transmitted to the rotor, which rotates. The comb tooth structure amplifies the vibration. We chose a material with high friction to increase the torque. The maximum torque is 1.2 Newton meters, which is 5 to 10 times higher than a DC motor of the same size. The motor is also equipped with an optical encoder. (Photo taken on December 4, 2019, credit: Nikkan Kogyo Shimbun / Kyodo News Images)