Self-Aligning Roller Bearing Layout for Uneven Axial-Radial Loads
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Solution Overview
Problem
Double-row self-aligning roller bearings used in wind turbine generators face limitations in load capacity due to dimensional standards, where rollers in one row receive both axial and radial loads, leading to uneven contact surface pressures and reduced service life.
Innovation Solution
The design incorporates rollers in two rows with different lengths and contact angles, where longer rollers with a larger contact angle bear the axial load and part of the radial load, while shorter rollers with a smaller contact angle bear the rest of the radial load, within the constraints of ISO standards, ensuring equalized contact surface pressures and increased load capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the length of rollers in the row receiving axial load is increased to increase load capacity, then the bearing width exceeds standard values specified in dimensional standards
Solution Approach 1:
The patent applies asymmetry by making the rollers in the first row (receiving axial load) longer than the rollers in the second row. This asymmetric roller length configuration allows the first row rollers to have greater load capacity for axial loads while the bearing width remains within standard limits, as the longer rollers are compensated by optimized contact angles rather than uniformly increasing all dimensions.
Solution Approach 2:
The patent changes the contact angle parameter differently for rollers in the two rows. The first row rollers have a larger contact angle than the second row rollers, which increases the load capacity of the first row rollers for axial loads without requiring an increase in bearing width. This parameter optimization allows the bearing to meet dimensional standards while achieving the required load capacity.
2Strength
If the contact angle of rollers receiving axial load is increased to increase load capacity, then the inner diameter exceeds standard values specified in dimensional standards
Solution Approach 1:
The patent applies local quality by assigning different contact angles to rollers in different rows based on their specific load requirements. The first row rollers (receiving axial load) have a larger contact angle optimized for axial load capacity, while the second row rollers have a smaller contact angle appropriate for radial load only. This localized optimization of contact angles allows each roller row to have appropriate load capacity without requiring an increase in inner diameter beyond standard values.
3Device complexity
If uniform roller lengths and contact angles are used in both rows, then the bearing structure is simple, but the contact surface pressures become uneven and service life is reduced
Solution Approach 1:
The patent applies local quality by making the rollers in the first row (receiving axial load) longer than the rollers in the second row. This asymmetric roller length configuration allows the first row rollers to have greater load capacity for axial loads while the bearing width remains within standard limits, as the longer rollers are compensated by optimized contact angles rather than uniformly increasing all dimensions.
Solution Approach 2:
The patent changes the contact angle parameter differently for rollers in the two rows. The first row rollers have a larger contact angle than the second row rollers, which increases the load capacity of the first row rollers for axial loads without requiring an increase in bearing width. This parameter optimization allows the bearing to meet dimensional standards while achieving the required load capacity.
Data Source
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AI summary
A double-row self-aligning roller bearing, which is suitable for receiving an axial load and a radial load, and loads having different magnitudes acting on rollers in two rows, and achieves sufficient load capacity for the rollers that receive axial load within the constraint of dimensional standards, is provided. The double-row self-aligning roller bearing includes inner and outer rings; and rollers in two rows arranged in a bearing width direction interposed between the inner and outer rings and having lengths different from each other. The roller has an outer peripheral surface of a cross-sectional shape along a raceway surface of the outer ring having a spherical shape. Length of the longer rollers is equal to or greater than 39% of the bearing width. A ratio of contact angle of the shorter rollers and contact angle of the longer rollers is within a range of 1:4 to 1:2.