Design of a noncontact spherical bearing based on near-field acoustic levitation

Based on near-field acoustic levitation, a noncontact bearing with a spherical rotor was proposed to explore its potential application for novel supporting bearing of suspended gyro. The stator of the noncontact bearing has a hollow bowl-shaped configuration, in order to produce acoustic levitation force for a spherical object. Two orthogonal flexural standing waves were piezoelectrically generated and led to a traveling wave in the stator, and then the induced high-intensity sound in the air gap between the stator and spherical rotor could apply levitation force and even driving force for the spherical rotor. In this article, finite element model of a bowl-shaped piezoelectric stator was built, and the dynamic analysis and parametric optimization for the stator have been conducted. The prototypes were manufactured and vibration parameters of the stators were experimentally obtained. The test system for the noncontact spherical bearing was built, and its levitation and driving characteristics were measured. The spherical rotor successfully achieved levitation and noncontact rotation based on near-field acoustic levitation and the experimental results preliminarily indicate the feasibility of near-field acoustic levitation for suspended gyro.