Experimental Study on Friction Characteristics and Running Stability of a Novel Ultrasonic Levitating Bearing

As a potential alternative to conventional non-contact bearings, ultrasonic bearings are especially suitable for high-speed power machines and the torque-testing devices within a small range. The friction characteristics of the proposed ultrasonic bearing are investigated. The friction torques at low speeds and high speeds are measured by pendulum balance method and current feedback method, respectively. By means of time-frequency spectrum analysis to the rotor center's orbits, the running stability of the bearing is studied when the bearing operates at starting or stopping stage and at high speeds. In addition, the influence on the bearing's running stability of some key factors including rotary speed, load on the bearing, and diameter clearance is revealed. The effective measures improving the bearing's running stability at a high speed are presented to guide the bearing's engineering application.