Air bearing

This article is licensed under theGNU Free Documentation License.It uses material from the Wikipedia article "Air bearing" (click for full Wikipedia text)

An  'air bearing ' is a bearing (mechanical) that literally consists of a layer of earth's atmosphere used as the working fluid for a fluid bearing. Air bearings are often used where the gap between moving surfaces must be small and where differential velocity is high enough to allow the viscosity of air to build up enough pressure to keep the moving surfaces separated. Examples of the use of an air bearing is the "flying head" in a computer's hard disk drive. Systems requiring highly precise motion typically incorporate air bearing technology in order to achieve accurate and repeatable motion with low friction and no wear. Common applications include machine tools, multi axis metrology systems, and spindles for the semiconductor and data storage industries. Air bearings with compliant spring foil to maintain journal clearances are called foil bearings. Air bearings fall under hydrodynamic lubrication. By hydrodynamic lubrication or aerodynamic lubrication we mean a process in which two surfaces, moving at some relative velocity with respect to each other, are separated by a fluid (be it liquid or gaseous) film in which forces are generated by virtue of that relative motion only. Airfoil bearings are a class of hydrodynamic air bearings that are self-acting fluid film bearings which require no external pressurization. A number of elements in the construction of foil bearings make for their superior behavior and performance even under unconventional conditions. Two mechanisms, one hydrodynamic or aerodynamic, and the other elastic, are instrumental in producing the exceptional qualities of foil bearings. The earliest fluid film foil bearings’ principal was demonstrated by Bloch & Van Rossum (1953). Air foil bearings are being used on an ever-wider range of machinery, small and large, in both familiar, new technologies and oil free turbomachineries. This is due to the fact that foil air bearings can tolerate severe operating conditions and can function in hostile environments, which for conventional bearings would, at the least, be a risky undertaking. In numerous cases aerodynamic foil bearings have proven to be the only ones to make the operation possible. The technological community based on the nature and potentialities of foil bearings have secured a modern place in advanced technologies that they deserve. The environmentally friendly airfoil bearings are widely used in oil free advanced high speed rotating machinery such as micro turbo-alternators, centrifugal compressors/blowers, small gas turbine engines, turbochargers, gaseous chemical handling turbocompressors, air cycle machine for trains or aircraft’ cabin pressurization, high speed brush less permanent magnet motors, fuel cell turbocompressors and medical grade air compressors and many more.

External links

• Air Bearing components for use in a variety of machine applications
• Glossary of Air Bearing industry terms
• Mohawk Innovative Technology, Inc.
• Nasa Foil Bearing Research
• Air bearing kits
• Aeris co. Machine moving Air Bearing manufcturers
• Manufacturing unique Air Bearing equipment
• move a B1 with your finger, from the company that moves Nasa's space shuttle
  
  This article is licensed under the GNU Free Documentation License.It uses material from the Wikipedia article "Air bearing" (click for full Wikipedia text) Hide