Fluid bearing

About: Fluid bearing is a research topic. Over the lifetime, 3340 publications have been published within this topic receiving 41034 citations.

The Role of Radial Clearance on the Performance of Foil Air Bearings

Abstract: Load capacity tests were conducted to determine how radial clearance variations affect the load capacity coefficient of foil air bearings. Two Generation III foil air bearings with the same design but possessing different initial radial clearances were tested at room temperature against an as-ground PS304 coated journal operating at 30,000 rpm. Increases in radial clearance were accomplished by reducing the journal's outside diameter via an in-place grinding system. From each load capacity test the bearing load capacity coefficient was calculated from the rule-of-thumb (ROT) model developed for foil air bearings. The test results indicate that, in terms of the load capacity coefficient, radial clearance has a direct impact on the performance of the foil air bearing. Each test bearing exhibited an optimum radial clearance that resulted in a maximum load capacity coefficient. Relative to this optimum value are two separate operating regimes that are governed by different modes of failure. Bearings operating with radial clearances less than the optimum exhibit load capacity coefficients that are a strong function of radial clearance and are prone to a thermal runaway failure mechanism and bearing seizure. Conversely, a bearing operating with a radial clearance twice the optimum suffered only a 20 percent decline in its maximum load capacity coefficient and did not experience any thermal management problems. However, it is unknown to what degree these changes in radial clearance had on other performance parameters, such as the stiffness and damping properties of the bearings.

Wafer polishing machine with fluid bearings

Abstract: A semi-conductor wafer polishing machine having a polishing pad assembly and a wafer holder includes a support positioned adjacent the polishing pad assembly. The support includes multiple fluid bearings that support the polishing pad assembly on the support. These fluid bearings are arranged concentrically to provide concentric regions of support for the polishing pad assembly, and each fluid bearing is coupled to a respective source of pressurized fluid at a respective pressure.

Bearing Design in Machinery: Engineering Tribology and Lubrication

Abstract: Classification and Selection of Bearings Lubricant Viscosity Fundamental Properties of Lubricants Principles of Hydrodynamic Lubrication Basic Hydrodynamic Equations Long Hydrodynamic Journal Bearing Short Journal Bearings Design Charts for Finite-Length Journal Bearings Practical Applications of Journal Bearings Hydrostatic Bearings Bearing Materials Rolling Element Bearings Selection and Design of Rolling Bearings Testing of Friction and Wear Hydrodynamic Bearings Under Dynamic Conditions Friction Characteristics Modeling Dynamic Friction Case Study: Composite Bearing-Rolling Element and Fluid Film in Series Non-Newtonian Viscoelastic Effects Orthopedic Joint Implants Appendix A: Units and Definitions of Material Properties Appendix B: Numerical Integration Bibliography Index