In harsh operating environments, bearings are constantly under attack from contaminants such as dirt, abrasive materials, caustic chemicals, extreme heat and heavy shock loads.
Selecting the right bearing seal to protect against contamination is often the most important consideration when choosing a bearing and housing assembly.
Know your options when it comes to determining a reliable sealing system and prevent premature bearing failure caused by localized contaminants.
Integral vs. External Bearing Seals
Sealing elements fall under two major categories, which are based on whether the seal is integral or external to the bearing component. Each sealing type has its own unique considerations.
According to MachineDesign, integral seals are compact and eliminate the need for grease cavities and external shaft seals, which can require more space and impose a mechanical burden on the shaft. External seals, however, are frequently used with oil rather than grease, as oil is often present in high-speed applications and where lubrication is shared between multiple components. External seals are also commonly used in applications that require regreasing or a large lubrication cavity
Contact vs. Non-Contact Bearing Seals
Seals can also be contact or non-contact by design. With a non-contact seal, there is no contact with the bearing’s inner ring. Conversely, a contact seal is designed to contact the bearing’s inner ring with the lip of the seal.
Choosing the best seal depends on the bearing application and environment. Contact seals, although they produce more friction, provide a better seal against fluids or small contaminants, like dust. Non-contact seals, on the other hand, are preferable for clean, heavy-duty environments, such as aggregate.
Schaeffler offers a virtually impenetrable external non-contact labyrinth seal design that has stood the test of time—FAG SuperTac II Taconite Seals. 
Non-contact seals typically include the following features: oil grooves, labyrinths and flingers. Schaeffler’s SuperTac II Sealing system includes a grease-packed radial labyrinth, as well as a grease-purged axial labyrinth, that create a practically impermeable web of protection against contamination. The result: a longer bearing life.
Within the SuperTac II Sealing system, the grease-packed radial labyrinth with a grease-purged axial labyrinth creates a practically impermeable web of protection against contamination, resulting in a longer bearing life.
The SuperTac’s non-contact seal design eliminates shaft wear, has exceptional high-speed capabilities and can accept greater misalignments than lip seals. The benefit to you: machine downtime is kept to a minimum.
Additionally, FAG SuperTac II Taconite Seals were designed as a drop-in fit into the seal grooves of SAF pillow blocks – including FAG and many other competitors’ brands – which eliminates the need for special housing features.
