Home » Blog » Bearing Closures: Bearing Seals and Bearing Shields Part 2

Bearing Closures: Bearing Seals and Bearing Shields Part 2

March 4, 2019 by Christine Berlly

Welcome to Part 2 of our blog series on bearing closures (Read Part 1 here), where we continue to discuss how closures can extend bearing life and help retain lubricant. Following are descriptions of the most common bearing closure types AST can supply.

Type 2RU – Molded rubber seal, non-contact. This type of seal is Buna-N bonded to a steel insert. The seal is fixed into a groove in the outer ring. This type of seal can be removed, but care must be used not to bend or cut the seal lip. Max operating temperature is 240° F.

This type of seal has a very thin lip adjacent to the inner ring, but does not make contact. It provides better protection than type ZZ or ZZS, but without the increase in torque exhibited by type 2RS. Certain lubricants and chemicals react with rubber. The code for a single seal is RU.

Type 2VS – Molded Viton seal. This type of seal is made of Viton bonded to a steel insert. The seal is fixed into a groove in the outer ring. This type of seal can be removed, but care must be used not to bend or cut the seal lip. Max operating temperature is 400° F.

This type of seal makes contact with the inner ring, providing better protection in contaminated environments than a metal shield. However, this results in an increase in torque and reduces the max speed capability of the bearing. This seal has excellent chemical resistance. The code for a single seal is VS.

Type TTS – Glass reinforced PTFE seal is retained in the outer ring with a snap wire. This type of seal can be removed, but care must be used not to bend or cut the seal lip. Max operating temperature is 400° F. This type of seal makes contact with the inner ring, providing better protection in contaminated environments than a metal shield. However, this results in an increase in torque and reduces the max speed capability of the bearing.

This type of seal exhibits less torque than type 2RS, but is more delicate. This seal has excellent chemical resistance. The code for a single seal is TS. Teflon seals are only available on certain series of bearings.

AST’s consultants and engineers are ready to provide further information about ball bearing cages and any other bearing questions. Contact them here.


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