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 RADIAL CLEARANCE OF A BEARING
In order to
freely rotate, a ball bearing must have a certain amount of
internal freedom of movement (internal clearance,
or the space between the raceway and ball). Without this
internal clearance, the bearing can be difficult to rotate or
may even freeze-up and be impossible to rotate. On the other
hand, too much internal clearance will result in an unstable
bearing that may generate excessive noise or allow the shaft
to wobble. The internal clearance is measured in terms of the
direction of the load (radial internal clearance
and axial internal clearance).
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| 1.Radial
Clearance |
2.Axial
Clearance |
3.Moment
Clearance |
In our country radial clearance of the
bearings known as 'dug' or 'play' and certain class of people
do not prefer to use the bearings having radial clearance. But
for most of the application radial clearance is a must. This
statement is supported by the following arguments. Infact,
redial clearance in the bearing is an important factor.
Measuring
Radial Internal Clearance
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The example shows a radial ball bearing,
so the radial internal clearance is measured. The
bearing is grasped at one point on the inner ring and at
another point on the outer ring, directly opposite (see
large arrows). The bearing is held together to assure
radial contact between the inner raceway, balls, and
outer raceway. This allows measurement of the
bearing’s internal clearance at a point on the
opposite side of the bearing--180°--
from where the points of contact are being made. The
small gap between the top ball and the raceway
represents the bearing’s radial internal clearance.
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There is a designation system for indicating the
radial clearance of bearings. Following designation indicates
the magnitudes and clearance.
DESIGNATION
MAGNITUDE OF CLEARANCE
C I
*radial clearance smaller than c2
'0'
or c2 =radial clearance
smaller than Normal
'00' or
cn =normal radial clearance
'000' or c3
=radial clearance greater than normal
'0000' or c4
=radial clearance greater than c3
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