Rolling Bearings Lubrication and Sealing
Rolling bearings have been in use since the late 19th century to provide long-lasting and reliable performance in heavy-duty machines. Although they have evolved and become more sophisticated over time, the basics of lubrication and sealing remain the same. This article will provide an overview of the two components involved in successful bearing operation—lubrication and sealing—and cover the benefits of ensuring proper performance for each.
Lubrication
When a bearing is exposed to heavy loads, friction is created between the rolling elements, their raceways and the cage (especially at higher speeds). The use of lubrication is essential to reduce friction, heat and wear of the bearing components. The role of lubrication is extremely important to the effective working of the bearing, providing both protection and cooling. Lubricants reduce friction, reduce electrical conductivity, protect against corrosion and make bearing exchange easier.
In order to ensure effective lubrication of a bearing, the lubricant must be selected based on the operating conditions, type of bearing and desired bearing lifetime. Bearing manufacturers provide information on the types of lubrication that can be used and a special lubricant for a specific purpose such as high temperature or high-pressure environments should be used. The condition of the lubricant should also be regularly monitored and checked for signs of contamination.
Sealing
A roller bearings inner and outer stainless steel rings, along with its rolling elements and the cage, can also be partially filled with a viscous oil-based sealant, as well as a wiper to prevent contaminants from entering the bearing. This helps prevent the lubricating oil from leaking out and ensures that it is contained within the bearing. There are three types of bearing seals available, contact, labyrinth and non-contact seals, the choice of which depends on the bearings application.
The use of contact seals is the most common and they are typically made of lip-type seals that tightly hug the bearing and are relatively simple to install. Labyrinth seals are also a good choice for many applications and provide an excellent protection with minimal friction. Finally, shielded or non-contact seals are typically used in applications where contamination needs to be kept out, but particularly in low to medium speed applications.
Conclusion
The lubrication and sealing of roller bearings are important components of ensuring successful operation within any given application. The areas of lubrication and sealing should always be taken into consideration to ensure the longevity of the bearing and to reduce costly repairs or replacements. By carefully selecting a suitable lubricant and seal type for their bearing, users can expect optimal performance. Furthermore, routine lubricant checks and maintenance of the bearing seals can be beneficial in helping to avoid any potential problems and extend the life of the bearing assembly.
