An Investigation to the Design of Vacuum Preloaded Air Bearings With Respect to Reproducibility

Vacuum preloaded (VPL-) air bearings are generally designed by combining a collar bearing and a central area where vacuum is drawn (Figure 1). Sometimes the bearing area and vacuum area are separated by a groove which is connected to ambient pressure in order to prevent flow from the pressurized area to the vacuum ejected area. The collar bearing around the vacuum area is generally orifice compensated, compensated by a porous surface or by shallow grooves applied in the bearing surface. In this paper a study is presented towards the design of bearing configurations with the highest axial bearing stiffness that can be machined with good reproducibility. Various bearing configurations are analyzed analytically and numerically and the performance of the analyzed bearings are compared to each other.