Experimental investigations of ultrasonic levitation in a machine tool spindle system

An investigation into a non-contact bearing for machine tool spindle system that functions on the squeeze film ultrasonic levitation is conducted in this paper. Squeeze film type ultrasonic levitation is investigated experimentally and compared with the performance predicted by the theoretical models. A prototype non-contact journal bearing is developed for suspension of a solid steel spindle with diameter of 50 mm. The maximum load capacity of 51 N (6.37 N/cm²) is obtained which is considerably larger than the previously reported squeeze film bearings whose load capacities are usually within a few Newton (less than 1 N/cm²).