Design and Investigation on Static and Dynamic Characteristics of Aerostatic Bearings with Non-Coplanar Orifice and Groove

Aerostatic bearings are extensively applied in the motion stage systems of cutting-edge equipment such as lithography machines. In this paper, a novel aerostatic bearing with non-coplanar orifice and groove (NCOG) is proposed, which effectively addresses the issue that the air supply tubes affect the high-speed motion accuracy of aerostatic guideways. Based on the gas lubrication theory, a three-dimensional computational fluid dynamics (CFD) model is established to analyze the pressure distribution and flow field status of the aerostatic bearing with NCOG. This reveals the lubrication mechanism as well as the static and dynamic characteristics of the aerostatic bearing with such a structure. The results indicate that the aerostatic bearing with NCOG can achieve the same functionality as traditional bearings with identical structural dimensions. The research on static characteristics shows that increasing the orifice diameter and the groove depth can enhance the pressure within the groove. The results of the dynamic characteristics study demonstrate that increasing the orifice diameter can reduce the micro-vibrations of the bearing. Additionally, when the groove depth is less than 0.04 mm, the turbulent kinetic energy (TKE) of the bearing increases with the increase in groove depth, while when it is greater than 0.04 mm, the TKE decreases with the deepening of the groove. Notably, when the groove depth exceeds 0.1 mm, the TKE of the bearing decreases sharply. The effectiveness of the CFD model and the accuracy of the conclusions regarding the static and dynamic characteristics are verified through experiments.