The Effect of Vacuum on Driving Properties of Ring Type Ultrasonic Motor

Ultrasonic motor(USM) is one of the promising actuators that are utilized under vacuum conditions.There are a few studies on it in vacuum.Properties of rotational speed and torque of nonmagnetic and common ring type traveling wave ultrasonic motors in normal,low vacuum and high vacuum were studied respectively by using vacuum tester and simulating tester of USM′s properties.It was found that both rotational speed and torque of the two USMs decreased as the environment pressure decreased.Under vacuum condition,the load properties of common USM were worse than those under normal condition.The load properties of nonmagnetic USM were affected a little by environment pressure.Nonmagnetic USM had better load properties than common USM.Acoustics suspension and tribology theories were applied to primarily analyze these phenomena.