Vortex suppression and nano-vibration reduction of aerostatic bearings by arrayed microhole restrictors

Abstract

Air vortex flow can induce small amplitude vibration of aerostatic bearings on the order of nanometers, which is known to be harmful to positioning accuracy of aerostatically supported devices in ultra-precision applications. In this paper, in order to suppress the vortex flow and reduce vibration of aerostatic bearings, a novel design of arrayed microhole restrictor (AMR) is proposed, and its effects are numerically and experimentally investigated. By computational fluid dynamics analysis, the transient flow features are studied for aerostatic bearings with AMR and conventional restrictors, and static performances of the bearings are also compared. Vibration strength of the bearing is measured experimentally to validate the effectiveness of AMR. The results show that vortex shedding in the recess is suppressed and the vibration can be effectively reduced by AMR, while load capacity and stiffness of the bearing remain unchanged.