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Protective closures are used to inhibit the entrance of particles
or to retain lubrication within the bearing. The two common
types of closures are shields and seals.
Shields are used when some protection of the bearing is needed
but no negative effect on torque or speed can be tolerated. The
standard shield is a non-contact metal shield and can be specified
in either removable or non-removable varieties.
Seals can be specified in either full contact or non-contact
varieties and in various materials. Full contact seals in synthetic
rubber are used either when complete protection of the bearing
is required, or when lubricant migration cannot be tolerated in
the application. They can also withstand slight positive pressure
differentials. The main disadvantage of contact seals is the
increase in torque and the decrease in running speed capability.
Non-contact seals can help to overcome some of the torque and
speed issues, though some compromise is made in sealing ability.
These seals can be made in synthetic rubber or reinforced
PTFE, with PTFE offering the lowest torque in the event of slight
contact.
Protective closures are a design decision that is not necessarily
black and white. We encourage you to discuss the selection of
closures with one of our
Application Support specialists.
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