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Seals and Shields

NHBB offers a variety of protective closures designed to retain lubricants and prevent contamination from reaching critical bearing surfaces. When specifying closures, consideration should be given to bearing width● and the compatibility of retainer and shield type to allow for appropriate clearance. Depending on the requirements of your application, it may be necessary to customize a closure by modifying the types listed here. Please contact NHBB HiTech’s Applications Engineering department for information about special designs that may be better suited to your particular application.

Seal Types

Seals are generally used in high contamination environments where a positive closure is required, but they can increase torque and heat generation, which may affect operating speed limits.


D, D1

S, S1

Q

Q4

Shield Types

The shields shown below provide a barrier to gross contamination without unduly affecting speed and torque.


H

Z

Table of Seals and Shields

Type Description Material Max. Temp. Speed Limit (dN♦) Comments
D Seal — removable Nitrile rubber bonded to steel insert 250° F 180,000 Positive contact, high torque, most effective in excluding contamination
D1 Seal — removable Fluorocarbon rubber bonded to steel insert 400° F 180,000 Positive contact, high torque, most effective in excluding contamination
Q Seal with snap wire — removable Glass reinforced PTFE* 600° F 200,000 Positive contact, lower torque than D or D1, very effective in excluding contamination
Q4 Seal with outboard shield and snap wire — removable Glass reinforced PTFE*, 300 series stainless steel 600° F 200,000 Positive contact, high torque, most effective in excluding contamination
S Seal — removable, noncontact Nitrile rubber bonded to steel insert 250° F No influence on speed Noncontact, no effect on bearing torque, less protection than D or Q
S1 Seal — removable, noncontact Fluorocarbon rubber bonded to steel insert 400° F No influence on speed Noncontact, no effect on bearing torque, less protection than D or Q
Z Shield — removable, noncontact 300 series stainless steel 600° F No influence on speed No effect on bearing torque, less protection than seal
H Seal — nonremovable 300 series stainless steel 600° F No influence on speed No effect on bearing torque, less protection than seal

♦dN = bore (in millimeters) x rpm.

*Polytetrafluoroethylene is a high-melt-temperature thermoplastic.

● Width dimensions noted in the product tables of this Design Guide are for open bearings. Please consult the factory to identify widths for bearings with closures. In NHBB’s part numbering system, RW refers to radial bearings with cartridge widths.