Aeronautical needle roller bearing
MS21438/MS21349 series RBC Bearings

This is a non-separable unit, comprising an inner ring,
needle rollers, retaining washers, seal/thrust washers,
and an extra-thick outer ring to withstand heavy rolling
loads. The end washers are fastened to the inner ring.
Type ATF has a single row of rollers and type ATL has
two rows of rollers. The outer ring of type ATF bearing is
The seals on the ATF and ATL bearings are located in
counterbores of the outer ring and seal against the O.D.
of the end washers, providing a good retention of
lubricant and exclusion of foreign material. Seal/thrust
washers, made of a self-lubricating resin material,
separate the steel thrust surfaces, extending the life of
lubricant and bearing.
Grooves and holes for relubrication are provided in
the inner ring only, since the outer ring must serve as a
roller. Type ATF has a groove in the bore of the outer ring
for storage of additional lubricant. For protection from
corrosion under heavy rolling loads, the O.D. of the
bearing is chrome plated. Other exposed surfaces, as
mounted, are cadmium or zinc-nickel plated. Inner rings
are oxided.


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