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Bearing Closures

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 Barden. Please see the below table for operating information:

Shield

SS Shield

Barshield

AA Barshield™

Flexeal

FF Flexeal™

Synchroseal

UU Synchroseal™

Barseal

Barseal™

Deep Groove Bearing Closure Types

Closures for deep groove bearings Maximum speed    
Type Use Material Construction Benefits (dN units) Operating Temperature Range Limitations
SS Shields Low torque, high speed closure that can provide lubricant retention & limited contamination protection 302 stainless steel Precision stamping Maximum lubricant space, resistance to vibration Not limited by shield design 315°C 600°F Limited contamination protection
AA Barshield High speed rubber shield that provides improved protection from contamination without reducing allowable operating speeds Rubber, metal insert Rubber material bonded to metal stiffener Good exclusion of contamination without a reduction in operating speed Not limited by shield design -38°C to 107°C -30°F to 225°F May not prevent entrance of gases or fluids
FF Flexeals Minimum torque, low friction seal that provides lubricant retention and contamination protection Aluminium/ fiber laminate Precision stamping and bonding Excellent exclusion of contamination, resistance to aircraft hydraulic fluids 650,000 150°C/300°C Continuous 176°C/350°C Intermittent May not prevent entrance of gases or fluids
UU Synchroseal Specialised seal suitable for low torque applications Teflon filled fiberglass Thin ring, piloted in a specially designed inner ring notch Low torque, positive seal that can prevent entrance of solid, gaseous or liquid contamination 100,000 315°C 600°F Limited to low speed operation
YY Buna-N-Barseal YY closures provide improved sealing performance compare to Flexeals Buna-N rubber, metal insert Rubber material bonded to metal stiffener Excellent positive sealing to prevent the entrance of foreign contaminates 180,000 -54°C to 107°C -65°F to 225°F Limited to relatively low speed and temperature operation
PP Polyacrylic Barseal Polyacrylic Barseals provide a positive seal & allow for higher temperature operation than YY seals Polyacrylic rubber, metal insert Rubber material bonded to metal stiffener Excellent positive sealing to prevent the entrance of foreign contaminates 180,000 -21°C to 130°C -5°F to 265°F Requires relatively low speed operation
VV Viton Barseal While similar in design to YY and PP seals, VV seals provide for high temperature operation Viton rubber, metal insert Rubber material bonded to metal stiffener Excellent positive sealing to prevent the entrance of foreign contaminates 180,000 -40°C to 288°C -40°F to 550°F Viton material provides excellent thermal & chemical properties and is the material of choice for aerospace bearings

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The Barden Corporation (UK) Limited
Plymbridge Road, Estover
Plymouth, Devon
PL6 7LH, UK
Tel: +44 (0) 1752 735555
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