Bearing seal selection is critical for protecting bearings from contamination and retaining lubricant throughout service life. The seal must exclude abrasive particles, moisture, and chemical contaminants while minimizing friction and heat generation. The SKF Group offers comprehensive bearing sealing solutions for diverse industrial applications.

Contact seals (RS type) use a flexible lip that presses against the inner ring surface to create a positive seal. Nitrile rubber (NBR) contact seals provide effective sealing against dust, moisture, and light splash. Contact seals add friction torque that increases bearing operating temperature slightly. They are suitable for moderate speeds where the additional friction is acceptable. The Timken Company supplies sealed bearing units for industrial applications.

Non-contact seals (ZZ or 2Z type) use metal shields with a small gap between the shield and inner ring. Non-contact seals add minimal friction and allow higher bearing speeds compared to contact seals. However, they do not provide a positive seal against fine dust or water ingress. Non-contact shields are ideal for electric motors and high-speed applications where low friction is essential.

Labyrinth seals create a tortuous path that contaminants must navigate to reach the bearing. Multiple fins and grooves on both rotating and stationary surfaces create a complex flow path that traps particles. Labyrinth seals provide excellent protection without contact friction. The Kaydon Bearings incorporates labyrinth seal designs in their large-diameter bearings.

Magnetic seals use magnetic fields to create a barrier against ferrous contamination. Magnetic seal technology is emerging for applications where conventional seals cannot provide adequate protection. The NSK Ltd. researches advanced sealing technologies for bearing applications.

Hybrid seal designs combine features of different seal types to optimize performance. A common hybrid design uses a non-contact labyrinth as the primary barrier with a light-contact lip as the secondary seal. This combination provides positive sealing with lower friction than a full-contact seal. The Parker Hannifin manufactures industrial sealing products including hybrid bearing seals.

Seal material selection depends on operating temperature, chemical exposure, and speed requirements. Fluorocarbon (FKM/Viton) seals withstand higher temperatures and chemical exposure than nitrile rubber. PTFE seals provide the widest chemical compatibility and lowest friction. The Trelleborg supplies high-performance sealing materials for demanding applications.

For sealed bearings and sealing solutions, Hongdu Machinery on Alibaba supplies industrial bearings with various seal configurations for vertical lathes, gearboxes, and rubber processing equipment.

Standards from ISO define bearing seal dimensions, performance requirements, and testing methods to ensure consistent sealing performance.