为研究超声悬浮轴承的静、动态承载特性, 设计了一种压电陶瓷驱动的全包围结构超声悬浮轴承。分析了气体挤压膜润滑承载机理,在等温隔热条件下, 根据牛顿流体的气体动力学理论, 建立了描述轴承启动阶段及支撑回转体稳定旋转阶段气膜压力的静、动态雷诺方程。采用有限差分法并利用MATLAB自定义函数的功能, 对超声悬浮轴承的静态及动态承载力进行了数值计算。为验证理论计算的正确性, 通过轴承样机自悬浮实验验证轴承悬浮特性的理论计算结果, 得出在其谐振频率下, 相同结构尺寸及悬浮参数的轴承静态承载力理论计算值与测量值之间的误差为8.33%; 在挤压数为100, 2~5 μm合理初始间隙下, 动态悬浮力理论计算值与实验测量值相吻合。考虑样机结构特性引起的能量转换误差及实验环境因素影响, 误差在合理允许范围之内, 验证了理论分析及计算的正确性,对超声悬浮轴承的理论研究及设计具有一定的指导意义。

An ultrasonic levitation bearing based on piezoelectric actuation is designed to study the static and dynamic capacities of an ultrasonic levitation bearing. In this paper, calculations and numerical simulations of the levitation force of a gas squeeze film bearing were done using the finite difference method and a MATLAB function to calculate discrete equations for numerical calculations. The Reynolds equation describing the pressure distribution of the gas film was established for the bearing′s start-up and stable operation, according to the theory of gas dynamics of a Newtonian fluid, under the conditions of isothermality and adiabatic process and based on lubrication and load mechanism of a gas squeeze film. In addition, a bearing prototype was fabricated to measure the bearing capacity. For the resonant frequency, there is a difference of 8.33% between the theoretical value and the experimental result for the same size and levitation parameters. For the dynamic levitation force, the measurement results agree well with the solution of the theoretical calculations when the squeeze number is 100 and the initial gap is between 2-5 μm. Studying the impact of electro-mechanical conversion and the experimental environment provide a basis for future ultrasonic levitation theory research and design.