Item 1324
OTHER: Mechanical -
Bearing - Elastomeric - Shim
Shim Material:
Rotorway uses brass shims.
Lord mentions the start of using composite shims in a 1978 article. A picture in this article shows a collection of differing diameter shims for a radial bearing They are black (probably carbon) and the cloths threads appear to be at a X-ply of 45º and 135º.
Lord mentions the use of steel, aluminum, alloy, stainless steel, titanium and composites. It mentions in 1978 article that composites is the direction. It also shows an identical steel and composite part, where the composite's weight is 19% of the steel's.
It mentions that the composite winding pattern was found to be critical.
It appears that the preferred composite is graphite/epoxy.
Materials:
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Shims : ~ Non-extensible Materials |
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Stainless Steel |
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Titanium |
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Steel |
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Aluminium |
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Carbon composite |
Shims:
Use of Carbon Composite: by DJ
Just a thought re making radial bearings in carbon; ~ We could, cheaply, make our own short rigid tubes, in the required different diameters by making them in carbon out of braided carbon tubing over different sized mandrels. See: http://www.cstsales.com/carbon-sleeve.htm
Just a thought re making thrust/radial bearings in carbon; ~ In fact it might be possible to produce all the conical washers, in carbon, with different radiuses, at the same time by making up the sandwich in a simple mold and then vacuum bagging it. The rubber in the final product will replace the bleeder plies that are located between the carbon plies during curing.
Carbon was mentioned as an alternative to, say, stainless steel for the rigid disk portions of the bearing. It will have its pros and cons, like metal has, and was only thrown out as an alternate idea for consideration.
Carbon fiber is a very strong material in tension and is very light weight. Much more so than metals. The non-extensible (rigid) disks (shims) are in tension because the bulging action of the bonded elastomeric is attempting
to increase the overall diameter of the shim. Very thin shims can be made from 2 plies of bi-directional fabric, giving fibers at 45 degree azimuths, or 3 plies giving 30 degree azimuths. The cloth is placed in the mold with the epoxy etc., somewhat similar to working with fiberglass, and the part is made.
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Last Revised: May 13, 2004