Ultrasonic motor


A motor that uses ultrasonic vibration transmitted through the elastic mechanical members.

An ultrasonic motor stator is pressed to a rotor to transform ultrasonic vibration to mechanical output motion. Ultrasonic motors have the following characteristics: 1) a simple structure assisting miniaturization and light weight, 2) direct drive capability with high torque in the low-speed range, 3) a high power-to-weight ratio, 4) quick response, 5) good controllability, 6) the ability to maintain the rotor position because of a self-holding force when the power supply is off, and 7) no magnetic noise. On the other hand, problems include the friction and wear that occur between the stator and the rotor. Ultrasonic motors can be driven by standing wave or progressive wave. The former offers high energy conversion efficiency, while the latter gives excellent controllability because forward and reverse rotations are possible. Generally, ultrasonic motors are used in direct drive applications requiring low speed and high torque performance.


[Related Terms]
Piezoelectric linear actuator, Piezoelectric element