Sealing in bearings plays a critical role in safeguarding their performance and longevity. It prevents solid contaminants and moisture from entering the bearing while simultaneously retaining the lubricant within the bearing or its arrangement.
Even the best bearings can face premature wear, contamination, and failure without proper sealing. This article explores the critical role of sealing in bearings, the types of seals available, and how to select the right sealing solution for your application.
Why Sealing Matters in Bearings
Bearings are often exposed to harsh environments where dirt, dust, water, and other contaminants are prevalent. These contaminants can compromise the lubricant inside the bearing, leading to increased friction, heat, and eventual damage. Seals act as protective barriers that prevent external contaminants from entering and to retain the lubricant within the bearing.
To ensure optimal efficiency, seals must minimize friction and wear, even under the harshest operating conditions. By maintaining their effectiveness, they protect the bearing’s performance and extend its service life, making them indispensable components in demanding industrial environments.
How to Select the Right Bearing Seal
Many factors have to be considered when selecting the most suitable sealing for a particular bearing arrangement:
- the type of lubrication (oil or grease),
- the peripheral speed at the sealing surface,
- the shaft arrangement (horizontal or vertical) and possible shaft misalignment,
- the space available,
- the friction in the seal and the temperature increase resulting from it,
- environmental influences, justifiable costs, etc.
The selection should be maintained carefully, considering the operating conditions, the cost of the seal and total effects included (costs of replacement of a bearing should be taken into account as well).
Types of Sealing
Non-contact sealing
The effectiveness of non-contact seals depends in principle on the sealing action of narrow gaps between rotating and stationary components. The gaps may be arranged radially, axially or axially and radially in combination.
Non-contact seals have practically no friction and do not wear. They are generally not easily damaged by solid contaminants. They are particularly suitable for high speeds and high temperatures. Their sealing efficiency may be enhanced by pressing grease into the gaps.
Contact seals
The action of contact seals depends on the seal exerting a certain pressure at the seal/ sealing contact area, usually by a sealing lip or surface, which is relatively narrow. The penetration of solid contaminants or moisture and /or the loss of lubricant are thus prevented.
The pressure may be produced either by the resilience of the sealing material and the designed interference between the seal and the sealing surface or from the force exerted by a garter spring incorporated in the seal.
Contact seals generally provide very reliable sealing, particularly when wear is kept to a minimum by producing an appropriate surface quality on the sealing surface and by lubricating the seal lip.
The friction of the seal on the sealing surface and the rise in temperature that it generates are a disadvantage, and contact seals are therefore only useful up to certain peripheral speeds. They are also susceptible to mechanical damage, for example, because of improper mounting or by solid contaminants.
Key Takeaways
Sealing is a vital aspect of bearing performance, directly influencing reliability, efficiency, and lifespan. Choosing the right seal ensures your bearings can withstand even the harshest conditions, protecting your machinery and minimizing downtime.
If you’re ready to enhance the performance of your bearings or need expert advice on sealing solutions, contact Codex today. Explore our range of bearings and sealing options to meet the demands of your industry.
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