Self-Aligning Roller Bearing Geometry for Balanced Load Sharing
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Solution Overview
Problem
Double-row self-aligning roller bearings used in wind turbine generators face uneven load distribution, leading to shorter rolling fatigue life and limited service life due to axial and radial loads, as rollers in one row receive both loads while others receive only radial loads, resulting in higher contact surface pressures and wear.
Innovation Solution
The design includes rollers in two rows with varying contact angles and lengths, where the ratio of contact angles between rows is optimized (0.25≤θ1/θ2≤0.5) and the distance distribution in the bearing width direction is adjusted (0.5≤B1/B2≤0.6) to equalize load sharing, with a DLC coating for enhanced wear resistance, ensuring the rollers can accommodate both fatigue and extreme loads within dimensional standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rollers of different lengths are arranged in two rows to equalize contact surface pressures, then the service life of the bearing is improved, but the bearing width exceeds standard dimensional values
Solution Approach 1:
The patent changes the contact angle parameter of rollers in different rows to equalize contact surface pressures. By setting different contact angles (θ1 and θ2) for rollers in the first and second rows respectively, the load distribution is optimized without requiring different roller lengths, thus avoiding exceeding standard bearing width dimensions.
2Strength
If the contact angle of rollers receiving axial load is increased to increase load capacity, then the load capacity is improved, but the inner diameter exceeds standard dimensional values
Solution Approach 1:
The patent optimizes the contact angle parameter within standard dimensional constraints. By carefully selecting the contact angles θ1 and θ2 to satisfy the relationship 0.2 ≤ θ1/θ2 ≤ 0.5, the load capacity is enhanced while maintaining compliance with standard inner diameter dimensions.
3Force
If rollers in one row receive both radial and axial loads, then the bearing can support combined loads, but the contact surface pressure becomes excessively high causing wear and fatigue
Solution Approach 1:
The patent applies different contact angle characteristics to rollers in different rows. Rollers in the first row have contact angle θ1 and rollers in the second row have contact angle θ2, where the ratio 0.2 ≤ θ1/θ2 ≤ 0.5. This local differentiation of geometric parameters allows each row to optimally handle the load components applied to it, equalizing contact surface pressures and preventing excessive stress.
Data Source
AI summary
Provided is a double-row self-aligning roller bearing including: an inner ring; an outer ring having a spherical raceway surface; and rollers arranged in two rows and interposed between the inner ring and the outer ring, wherein a ratio of a contact angle θ1 in one row to a contact angle θ2 in the other row falls within a range of 0.25≤θ1/θ2≤0.5, and a ratio of distance B1 in a bearing width direction from an end face of the bearing on a side of the one of the rows to an intersection of two lines of action defining the contact angles of the two rows, relative to a distance B2 in the bearing width direction from an end face of the bearing on a side of the other of the rows to the intersection falls within a range of 0.5≤B1/B2≤0.6.