Self-Aligning Roller Bearing Raceway Geometry for Lower Sliding
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Solution Overview
Problem
Self-aligning roller bearings experience high friction losses and material stresses due to high sliding speeds at the contact areas between rollers and raceways, particularly at the edge areas of the rolling contact, leading to roller setting and undesirable lateral sliding.
Innovation Solution
The raceways on the inner and outer bearing rings are tilted relative to each other around a common intersection point, with the inner bearing ring's raceways having groove points on a line that forms an angle with the vertical, reducing the radial distance from the groove point and altering the contact conditions to minimize sliding speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the raceways have a constant radius, then the manufacturing effort is reduced, but the sliding speeds at the edge areas remain high causing friction losses and material stresses
Solution Approach 1:
The patent applies local quality by implementing a non-constant radius only in the edge areas of the raceways, while the central area maintains a constant radius. This localized modification reduces sliding speeds and friction losses at the critical edge areas without requiring complete redesign of the entire raceway, thus balancing manufacturing effort with performance improvement.
Solution Approach 2:
The patent changes the geometric parameter of the raceway radius from constant to non-constant in specific areas. By varying the radius parameter in the edge areas, the sliding speed is reduced, which directly addresses the friction loss problem while maintaining manufacturability through controlled parameter modification.
2Loss of energy
If the raceways have a non-constant radius, then the sliding speeds are reduced, but the axial positioning of the rollers is impaired causing lateral sliding
Solution Approach 1:
The non-constant radius is applied locally only in the edge areas of the raceways, while the central area maintains a constant radius that ensures proper axial positioning of the rollers. This localized approach allows the edge areas to benefit from reduced sliding speeds without compromising the overall roller positioning functionality.
Solution Approach 2:
The patent applies the non-constant radius modification partially, only in the edge areas where sliding speeds are highest, rather than throughout the entire raceway. This partial action is sufficient to reduce friction losses while avoiding the excessive modification that would impair axial positioning.
3Reliability
If the groove points are positioned on the pressure line, then the contact area is optimized, but the radial distance from groove point increases causing higher sliding speeds
Solution Approach 1:
The patent modifies the position parameter of the groove points, moving them off the pressure line to a position where the radial distance is reduced. This parameter change directly reduces sliding speeds while the contact area remains optimized through the curved lateral surface geometry of the rollers.
Data Source
AI summary
A reduction in the setting of rollers in a self-aligning roller bearing is provided. The self-aligning roller bearing has inner and outer bearing rings and rollers arranged at least in one roller row. The rollers have a curved lateral surface the direction of the rotation axis and has a radius, and roll over curved raceways of the bearing rings. The raceways are each assigned a groove point around which the curved raceway extends at a radial distance in the direction of the rotation axis. A pressure line intersects the rotation axis at an angle of 90° at a point where these rollers have their largest roller diameter, and the radius of the curved lateral surface is smaller than both radial distances.