Single row self-aligning roller bearing is a rolling bearing with automatic self-aligning capability. Its core design compensates for the angular deviation (i.e. misalignment) between the shaft and the bearing seat through a special roller shape and inner and outer ring structure, while bearing large radial loads and certain axial loads. The following is a detailed analysis of its working principle:
1. Structural composition and key design
Outer ring
Spherical raceway: The inner surface of the outer ring is designed as a spherical surface, which forms a self-aligning structure in contact with the spherical surface of the roller.
Integral or split type: Usually it is an integral structure, but some large-sized bearings may adopt an outer ring split design for easy installation.
.Inner Ring
Double or Single Edges: The inner ring usually has double edges to fix the roller position, and some models may use a single edge design to simplify the structure.
.Cylindrical raceway: The inner raceway is cylindrical, in contact with the roller line, and bears radial loads.
.Roller
Symmetrical spherical roller: The roller is drum shaped (with a protrusion in the middle), with spherical ends, and is in contact with both the outer spherical raceway and the inner cylindrical raceway.
.Quantity and arrangement: The number of rollers is relatively large (usually 15-30), evenly distributed along the circumference to disperse the load.
.Retaining frame
Stamped steel retaining frame or solid retaining frame: used to separate the rollers, prevent them from rubbing against each other, and guide the rollers to rotate.
.Special design: Some models use window type retainers to improve the circulation of lubricating oil.
.2. Working principle: Automatic centering mechanism
Angle deviation compensation
When the shaft bends or is installed incorrectly (angle deviation ≤ 1.5 °~2.5 °), the inner ring tilts relative to the outer ring.
. The spherical end of the roller is in contact with the outer spherical raceway, allowing the roller to swing slightly in the inclined direction and automatically adjust the contact position to evenly distribute the load.Example: In a transmission shaft system, if the shaft bends due to force, a single row self-aligning roller bearing can compensate for the deviation through roller swing, avoiding stress concentration caused by edge contact.
.Load distribution and transmission
Radial load: transmitted through the linear contact between the roller and the inner and outer rings, with a large contact area and strong load-bearing capacity.
.Axial load: Due to the symmetrical arrangement of rollers, it can withstand bidirectional axial loads, but the axial bearing capacity is usually lower than the radial capacity.
. Composite load: When subjected to both radial and axial loads simultaneously, the contact stress between the roller and the raceway is automatically adjusted through spherical design to maintain stable operation.Rotation and lubrication
The cage guides the rollers to rotate along the raceway, reducing friction and wear.
. Lubricating oil enters the contact area through the cage window or roller gap, forming an oil film lubrication to reduce temperature rise and energy consumption.III. Core Performance Characteristics
High centering ability
It can automatically compensate for the angle deviation between the shaft and the bearing seat, reducing the impact of installation errors or shaft deformation on the bearing life.
. Comparison: The self-aligning angle of deep groove ball bearings is only about 2 '~4', while that of single row self-aligning roller bearings can reach 1.5 °~2.5 °.High load-bearing capacity
With a large number of rollers and a large contact area, the radial load-bearing capacity is 2-3 times that of deep groove ball bearings of the same size.
. Suitable for heavy-duty scenarios such as rolling mills, mining machinery, and wind turbine gearboxes.Resistance to impact and vibration
Spherical roller design can disperse impact loads and reduce local stress concentration.
. Example: In a vibrating screen, bearings need to withstand high-frequency impacts, and a self-aligning structure can avoid early failure caused by roller deflection.Low friction and temperature rise
The rollers are in linear contact with the raceway, and the friction coefficient is lower than that of sliding bearings.
. The design of the cage optimizes the flow of lubricating oil and reduces operating temperature (usually 10-15 ℃ lower than cylindrical roller bearings under the same load).