DESIGN AND ANALYSIS OF HYDORSTATIC GAS BEARINGS FOR VACUUM APPLICATIONS

摘要

Despite the apparent incongruity of operating bearing systems requiring a constant supply of pressurized gas in a vacuum environment, numerous systems of this type have been successfully operated to date [1]. Hydrostatic gas bearings provide the same benefits in vacuum that have made them a mainstay of precision engineering in atmospheric applications. Operation with minimal friction and complete freedom from stick-slip make them ideal for fast high precision servo applications. To some extent, the benefits are greater in vacuum, given the tendency of that environment to exacerbate the stick-slip phenomenon, combined with the limited selection of grease and oil lubricants available for vacuum applications, and their deleterious impact on delicate vacuum components such as cathode materials. While magnetic levitation devices have more recently been developed for similar applications, gas bearings have developed a significant track record in this field, including rotary and linear vacuum feed through bearings as well as large travel X-Y stages for accommodation of 300 millimeter silicon wafers.