The mounted bearings must be protected with sealing mechanisms. These mechanisms must carry out two basic functions:
• Prevent external dirt or humidity from entering.
• Prevent lubricants from leaking out.
The service life of the bearings very often depends on the efficiency of these mechanisms.
The sealing mechanisms may vary a lot, and various factors must be considered when choosing the one to be applied:
• Type of lubricant (oil or grease)
• Rotation speed
• Available space
• Seal friction
• Cost, etc.
All these mechanisms are grouped in two main families:
Frictionless sealing mechanisms
Especially appropriate for high speed, high temperature or relatively dry and clean environments.
They are the so called labyrinth seals, grooved seals, etc.
Sealing mechanisms with friction
They are simpler and are widely used.
Their reliability depends on the pressure exerted on the sealing surface. They are the so called retainer seals, ring seals, etc. and are usually made of rubber or resins.
Under severe cases of dirt, water, etc., the two types of sealing mechanisms may be combined.
Finally, it is worth mentioning that the possibility exists of using bearings individually protected with seal covers (double-tapered bearings) and properly lubricated. (Request information on types and models from the manufacturer).