Sealed self-aligning roller bearing is a type of bearing designed to withstand heavy loads with angular deviation or misalignment between the shaft and the bearing seat. Its core working principle combines self-aligning function and sealing mechanism. The following is a step-by-step analysis of its working characteristics:
1. Principle of heart regulating function
Structural design: Outer race raceway: adopts spherical design (usually with a curvature radius of 5-6 times the roller diameter), allowing for angular deviation between the bearing outer race and the bearing seat hole.
Inner raceway: It is a double raceway structure, with rollers symmetrically distributed in a drum or cylindrical shape.
Self centering mechanism: When the shaft deviates due to installation errors, thermal expansion, or load deformation, the outer ring can tilt relative to the inner ring (usually allowing angular deviation of 1-3 °), and the rollers automatically adjust the contact position between the inner and outer rings to evenly distribute the load.
Cage: guides roller movement, prevents direct contact between rollers, and reduces friction and wear.
2. Sealing mechanism
Sealing type: Contact seal: Rubber sealing ring (such as nitrile rubber NBR): Installed on both sides of the bearing, with lip and inner or outer ring interference fit, suitable for medium and low speeds and general polluted environments.
Metal labyrinth seal: forms a tortuous path through gap fitting, preventing pollutants from entering while reducing friction, suitable for high temperature or high-speed scenarios.
Non contact sealing: Gap sealing: relies on the viscosity of the lubricating grease inside the bearing to form a barrier, with a simple structure but weak sealing performance.
Sealing effect: prevent lubricant leakage (especially during vertical or inclined installation).
Block external pollutants (such as dust and moisture) from entering and extend the life of bearings.
3. Load distribution and compensation
Roller design: Drum shaped rollers can adapt to the inclination of the outer ring, maintain linear contact with the raceway, and avoid edge stress concentration.
Optimization of roller quantity and diameter to enhance radial load-bearing capacity (usually up to 3-5 times that of ball bearings of the same size).
Dynamic compensation: Under shaft deflection or vibration conditions, the roller automatically adjusts its position, balances load distribution, and reduces local overload.
4. Application scenarios and advantages
Typical applications: Agricultural machinery (such as harvester drive shafts), mining machinery (such as crushers), metallurgical equipment (such as rollers), and other scenarios where there is a risk of misalignment or deformation of the shaft system.
Core advantage: High adaptability: Tolerant for installation errors and shaft deformation, reducing dependence on machining accuracy.
Long lifespan: The ability to adjust the center reduces edge loads, and the sealing design delays pollution and lubrication failure.
Easy maintenance: The modular design facilitates the replacement of seals or the replenishment of lubrication.
5. Limitations
Limited axial bearing capacity: It needs to be used in conjunction with thrust bearings (such as a combination of self-aligning roller bearings and thrust ball bearings).
Speed limit: Friction of seals may limit high-speed performance (usually applicable to medium and low-speed conditions).
summarize
Sealed self-aligning roller bearings achieve dynamic compensation for shaft misalignment and adaptability to harsh working conditions through spherical raceway alignment and multi-layer sealing protection. Their design balances load distribution, sealing performance, and maintenance convenience, making them a key component under heavy and skewed working conditions.