Needle Roller Bearing Geometry for Thin-Wall Strength
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Solution Overview
Problem
There is a demand for rolling bearings with reduced friction and a compact radial size, requiring a smaller cross-sectional area while maintaining productivity and strength, as sliding bearings are being replaced by rolling bearings.
Innovation Solution
A rolling bearing design featuring a shell type outer ring with a raceway surface, needle rollers, and a retainer with a movement restricting portion, where the roller diameter and outer ring wall thickness have a specific relationship (0.5≤length D1/length T1<1.5) to achieve a reduced cross section and ensure proper load-bearing capacity and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the cross-sectional area of the bearing is reduced to achieve compact radial size, then the bearing becomes more compact, but the strength and load-bearing capacity may be compromised
Solution Approach 1:
The patent applies parameter changes by optimizing the ratio between roller diameter (D1) and outer ring wall thickness (T1) within the range 0.5≤D1/T1<1.5. This parameter optimization allows the bearing to achieve compact cross-sectional dimensions while maintaining sufficient strength and load-bearing capacity through the carefully balanced geometric relationship between key components.
Solution Approach 2:
The patent implements local quality by providing a raceway surface with specific surface treatment or hardening on the inner surface of the outer ring, where the load-bearing contact occurs. This localized enhancement of surface properties ensures high load-bearing capacity at the critical contact zone while keeping the overall wall thickness minimal, thus achieving compact size without sacrificing strength.
2Volume of moving object
If the roller diameter is reduced to minimize cross-sectional area, then the bearing becomes more compact, but the load-bearing capacity of individual rollers decreases
Solution Approach 1:
The patent applies segmentation by using multiple needle rollers arranged in parallel within the bearing. While each individual roller has a small diameter (D1≤2mm) to achieve compact size, the collective arrangement of multiple rollers distributes the load across many contact points, thereby maintaining sufficient total load-bearing capacity despite the reduced size of individual rolling elements.
Solution Approach 2:
The patent optimizes the relationship between roller diameter (D1) and wall thickness (T1) within the range 0.5≤D1/T1<1.5 to ensure that even with reduced roller dimensions, the bearing maintains adequate load-bearing capacity through the optimized geometric configuration and efficient space utilization.
3Volume of moving object
If the outer ring wall thickness is reduced to achieve compact size, then the bearing cross section is minimized, but the structural strength and stability are compromised
Solution Approach 1:
The patent maintains structural stability with reduced wall thickness by optimizing the ratio D1/T1 within 0.5≤D1/T1<1.5. This parameter control ensures the outer ring has sufficient rigidity and stability to support the loading conditions while keeping the wall thickness (T1) as small as possible to achieve compact bearing dimensions.
Solution Approach 2:
The patent enhances local quality by providing a raceway surface treatment or hardening on the inner surface of the outer ring where the rollers contact. This localized strengthening allows the outer ring to maintain high load-bearing capacity and structural integrity at the critical contact zone even with reduced overall wall thickness.
4Volume of moving object
If the bearing design is optimized for compact size, then the cross-sectional area is reduced, but the productivity of manufacturing may be affected
Solution Approach 1:
The patent specifies a practical parameter range (D1≤2mm and 0.5≤D1/T1<1.5) that balances compactness with manufacturability. These parameter guidelines enable standard manufacturing processes to produce the optimized bearing design efficiently, ensuring good productivity while achieving the target compact cross-sectional dimensions.
Data Source
AI summary
A rolling bearing includes a shell type outer ring having a raceway surface on an inside diameter side thereof, a plurality of rollers arranged on the raceway surface, and a retainer arranged on the inside diameter side of the shell type outer ring and retaining the plurality of needle rollers. The shell type outer ring includes a movement restricting portion that restricts a movement of the retainer in an axial direction. When a diameter of the rollers is a length D1 and a wall thickness of the shell type outer ring is a length T1, the length D1 is not more than 2 mm, and a relationship of 0.5≤length D1/length T1<1.5 holds.