These bearings are used where it is not
practical to use plain bearings, and where a high degree of reliability and
precision is required.
The advantages are:
·
Low frictional losses
·
Wide range of loads may be
accepted
·
Simple lubrication requirements
Ball Bearings
The most common type of bearing used on
aircraft. The ball bearing has many
variations in design allowing it to be used in a wide variety of situations/
They carry radial loads and moderate axial
loads in both directions and where a high axial load may be experienced, the
balls run in a deep groove in the races.
Caged Ball Bearings
In general use, for engine applications and
for equipment with rotational speeds in excess of 100 rpm. When used within engine/gearbox casings they
are lubricated with engine oil supplied by jets or by splash. When used outside casings, they are
lubricated by the application of grease which may be applied at specified
intervals by grease gun, or may be of the pre-packed type where lubricating
grease is packed and sealed into the bearing on assembly.
Crowded Ball Bearings
This bearing has filling slots in one or
both races and has no cage or separators.
The balls therefore touch each other during operation, hence the term ‘crowded’. They are suitable only where slow rotation or
part rotation (oscillations) are found, and are usually of the sealed or
pre-packed type.
Angular Contact Ball Bearings
Accept radial loads, and axial loads in one
direction where a single bearing may be used.
For axial loads in both directions
an opposed pair of bearings is often used.
