Influence of Pressure-Equalizing Groove on Static Load Performance of Aerostatic Guideway

Abstract

The load capacity and static stiffness of the existing air hydrostatic guideways are relatively low, and the static performance of the air film is degraded when external forces are increased during the process. Therefore, this study considered an aerostatic guideway of an ultra-precision micromachine tool as the research object. Single- and double-row orifice structures were designed on the guideway, and linear, extended, and X-shaped pressure-equalizing groove (PEG) structures with rectangular cross-sections were designed on the working surface of the guideway. By establishing a computational fluid dynamics model of the guideway air film, the pressure contour was obtained through simulation, and finally, the advantages of the double-row orifice structure were determined. Then, the influences of the structure, width, and depth of PEG and the diameter and number of orifices on the load capacity, stiffness, and air consumption were studied, which provided a theoretical basis for improving the load performance of the aerostatic guideway. The results showed that the design of the PEG effectively improved the load performance but increased the air consumption. The extended PEG exhibited the best load performance. When the eccentricity was large, the width of the PEG moderately increased, improving the load capacity and stiffness. While increasing the depth only improved the stiffness, it had little effect on the load capacity and air consumption. When the eccentricity was small, the diameter and number of orifices moderately increased. The experimental data were consistent with the simulation results, demonstrating the accuracy of the simulation method.

Keywords

• aerostatic guideway
• pressure-equalizing groove
• load capacity
• stiffness
• air consumption