Bearing closures are available in two basic types - shields and seals. Both closure types are generally ordered as integral components of deep groove bearings.
Closures serve the same purposes with varying effectiveness - they exclude contamination, contain lubricants and protect the bearing from internal damage whilst being handled.
Closures are attached to the outer ring of the bearing. Seals are defined as closures which contact the inner ring, while shields clear the inner ring. Both are designed so that the stringent precision tolerances are not affected by their use.
Selection of Closures
Determining the proper closure for an application involves a trade-off, usually balancing sealing efficiency against speed capability and bearing torque. Shields do not raise bearing torque or limit speeds, but they do have low sealing efficiency. Seals are more efficient, but they may restrict operating speed and increase torque and temperature.
Another consideration in closure selection is air flow through the bearing. This is detrimental because it carries contamination into the bearing and dries out the lubricant. It is preferable to use seals if an air flow is present.
A number of types of closures are available from us. Please contact us for more information.