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Foil bearings require no pressure system for the working fluid, so the hydrodynamic bearing is self-starting. Anti-wear coatings exist that allow over 100,000 start/stop cycles for typical applications. New third generation bearings can hold 9000 times their weight, at extremely high speeds. |
Foil bearings require no pressure system for the working fluid, so the hydrodynamic bearing is self-starting. Anti-wear coatings exist that allow over 100,000 start/stop cycles for typical applications. New third generation bearings can hold 9000 times their weight, at extremely high speeds. |
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Foil bearings were first developed in the late 1950s by [[Garrett Systems]] |
Foil bearings were first developed using independent [[R&D]] funds to serve military and space applications in the late 1950s by AirResearch Mfg. Co. of the Garrett Corp. [[Garrett Systems]] (later acquired by [[Honeywell]]). They were first tested for commercial use in [[United Airlines]] [[Boeing 727]] and [[Boeing 737]] cooling turbines in the early 1960s. Garrett AiResearch Air Cycle Machine Foil Bearings were first installed as original equipment in [[1969]] in the [[DC-10]]'s [[Environmental Control System]]s. Garrett-AiResearch foil bearings were installed on all U.S. military aircraft to replace existing oil-lubricated rolling-contact bearings. The ability to operate at [[cryogenic]] gas temperatures as well as at very high temperatures allowed foil bearings to have many other applications. |
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[[Capstone Turbine Corporation]] introduced the world's first oil free power generating [[microturbine]]s in 1998, made possible by foil bearings. [[Turbomachinery]] is the most common application because it operates at high speed. |
[[Capstone Turbine Corporation]] introduced the world's first oil free power generating [[microturbine]]s in 1998, made possible by foil bearings. [[Turbomachinery]] is the most common application because it operates at high speed. |
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Foil bearings are a type of hydrodynamic bearing. A shaft is supported by a compliant, spring loaded foil journal lining. Once the shaft is spinning fast enough, the working fluid (usually air), lifts the foil from the shaft so that there is no contact. The shaft and foil are separated by the viscous properties of the working fluid. A high speed of the shaft with respect to the foil is required to initiate the air gap.
Foil bearings require no pressure system for the working fluid, so the hydrodynamic bearing is self-starting. Anti-wear coatings exist that allow over 100,000 start/stop cycles for typical applications. New third generation bearings can hold 9000 times their weight, at extremely high speeds.
Foil bearings were first developed using independent R&D funds to serve military and space applications in the late 1950s by AirResearch Mfg. Co. of the Garrett Corp. Garrett Systems (later acquired by Honeywell). They were first tested for commercial use in United Airlines Boeing 727 and Boeing 737 cooling turbines in the early 1960s. Garrett AiResearch Air Cycle Machine Foil Bearings were first installed as original equipment in 1969 in the DC-10's Environmental Control Systems. Garrett-AiResearch foil bearings were installed on all U.S. military aircraft to replace existing oil-lubricated rolling-contact bearings. The ability to operate at cryogenic gas temperatures as well as at very high temperatures allowed foil bearings to have many other applications.
Capstone Turbine Corporation introduced the world's first oil free power generating microturbines in 1998, made possible by foil bearings. Turbomachinery is the most common application because it operates at high speed.
The main advantage of foil bearings is the elimination of the oil systems required by traditional bearing designs. Other advantages are:
Areas of current research are:
The main disadvantages are:
