Characterization of Vertical and Pitch Stiffnesses of Porous Vacuum Preloaded Air Bearings

摘要

Demands for high-resolution and high-speed machinery have been pushing the limits of bearing technology. Vacuum preloaded air bearings (VPL's) provide near-frictionless motion and high pitch stiffness against moments that are created when the actuation force or an external work force (e.g., due to cutting), does not align with the center of mass of a moving stage. The VPL uses a combination of air pressure and vacuum, as illustrated in Fig. 1. The vacuum under the bearing structure preloads the bearing against the guide surface, while the pressurized air prevents the bearing from making physical contact with the guide.