ball and roller bearings - NTN Bearing Corporation of America

such as a light bulb in the bore of the bearing, avoiding
direct contact until the inner ring has expanded sufficiently.
Another method is to heat the bearing in a bath
of hot oil. The oil must be clean, and the temperature
should not exceed 250° F. Higher temperatures may
cause the oil to decompose and the bearing to lose its
proper hardness.
Running Test
Illustration A
After mounting, a running test should be performed
to ensure that the bearing has been properly
installed. The shaft or housing is first rotated by hand. If
no problems are observed, a low speed, no load power
test is performed. If no abnormalities are detected at
this point, the load and speed are gradually increased to
operating conditions. If any unusual noise, vibration or
temperature rise is observed during the test, the procedure
should be stopped and the installation examined.
TECHNICAL
INFORMATION
Under normal conditions, bearing temperature rises
with rotation and then reaches a stable operating temperature.
If the temperature continues to rise and does
not level off, or if there is a sudden temperature rise, or if
the temperature is unusually high, the bearing should be
inspected.
Dismounting
Bearings are often removed as part of periodic
inspection procedures, or during the replacement of
other parts. The shaft and housing are almost always
reinstalled, and the bearings themselves are often
reused. Because of this, the same guidelines for cleanliness
in mounting apply to dismounting. (Illustration B)
Illustration B
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