Full definition
Sealed bearings are specially designed bearings that incorporate integrated seals to ensure longevity and reliability in various industrial applications. The primary function of these seals is to retain the factory-filled lubricant, typically grease, ensuring that it remains within the bearing throughout its operational life, which can last anywhere from 5 to 10 years under normal operating conditions. This design significantly reduces maintenance requirements, as the need for regular re-greasing is eliminated. Furthermore, the seals protect the internal components from external contaminants such as dust, dirt, and moisture, which can cause premature wear and failure of the bearing.
Sealed bearings are classified into two main types based on the sealing mechanism: the rubber or NBR seals designated as 2RS or 2RSH, and the non-contact metal shields labeled as 2Z or 2ZR. The 2RS type provides a tighter seal against environmental contaminants, while the 2ZR type offers lower friction torque due to its non-contact nature, making it suitable for applications where minimal resistance is crucial. The operating temperature range for these bearings is typically between –25°C to +110°C, with the 2RS seal variant being particularly robust in various temperature conditions. This wide operational range allows sealed bearings to be utilized effectively in diverse industrial environments, from manufacturing to automotive applications.
In terms of performance standards, sealed bearings are often referenced against the ISO 15 standard, which defines the boundary dimensions and tolerances for rolling bearings. This standardization ensures that sealed bearings can be universally integrated into a variety of machines and equipment, streamlining design and procurement processes across multiple sectors. Brands such as SKF, NSK, FAG, NTN, and Timken are known for their high-quality sealed bearings, which are engineered to meet specific industrial needs and provide reliable performance over extended periods.