An ultrasonic levitating bearing supporting radial and axial loads

An ultrasonic bearing that can support radial and axial loads simultaneously is proposed based on piezoelectric-driven principle and ultrasonic levitation technology. Supporting in two directions can be achieved only relying on single excitation source, which brings about compact structure and simple control. To predict the ultrasonic bearing's working frequency and acoustic impedance, acoustic impedance network of ultrasonic bearing is modeled. Finite element analysis (FEA) method is adopted to calculate the amplitude on radiating surface of the ultrasonic bearing. In order to verify the ultrasonic bearing's performance, a prototype is developed and levitating capability experiments are conducted. Results in the experiments demonstrate that the ultrasonic bearing shows good suspending performance and is able to support larger radial loads and certain axial loads simultaneously. The design of this kind of ultrasonic bearing will open up a new way to develop novel bearing structure in the future.