The most common cause of small bearing
failure is excessive force applied during assembly, which usually
results in the following adverse effects on bearing
performance:
Excessive forces during assembly of small bearings are
generated by poor handling techniques or incorrect/uncontrolled
interference due to poor design or tolerance stack up.
NEVER press fit a bearing to a mating component by
applying force across the bearing raceways through
the
balls. This will always result in brinelling damage
to the bearing. Press the inner ring for a press fit on
the shaft or the outer ring for a press fit in the
housing.
Calculate the effect of worst-case
tolerances on interference fits. Allow for thermal expansion
and material type in calculating the maximum loss of radial
play. Use a bearing with suitable radial play range. Loss of
radial play will change the mechanical characteristics of
the bearing (contact angle, torque, resonant frequency), and
can ultimately cause bearing
failure.
Excessive interference has cracked the
inner race.
Follow all guidelines for mounting practices. Make sure that
fixtures are aligned.
Bearings are susceptible to shock or impact loads, especially
when the axial play has been removed
through preload. Dropping
a preloaded assembly, or even placing it on a hard surface, can
cause
brinelling. It is recommended that assembly work surfaces
are covered with a layer of shock-absorbing
material.
Excessive forces during assembly of small bearings are
generated by poor handling techniques or incorrect/uncontrolled
interference due to poor design or tolerance stack up.
