Wheel Bearing Hub Axial Rigidity via Localized Diameter
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Solution Overview
Problem
Conventional wheel support bearing assemblies in automotive vehicles face challenges in achieving sufficient rigidity during cornering while maintaining a limited bearing diameter, which affects the vehicle's stability and rolling fatigue life, and often result in increased weight due to the need for enhanced structural components.
Innovation Solution
The design incorporates an outer member with a hub axle having an increased outer diameter at the midpoint between the rows of rolling elements, a thinned wall portion between the raceways, and an axial recess in the hub axle to enhance rigidity without increasing weight, while using balls with a specific pitch circle diameter and number distribution to optimize rolling fatigue life and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the outer diameter of the hub axle at the midpoint between rolling element rows is increased, then the rigidity of the bearing assembly is improved, but the weight of the bearing assembly increases
Solution Approach 1:
The patent applies local quality by increasing the outer diameter of the hub axle specifically at the midpoint between the rolling element rows (where rigidity is most needed to resist moment loads during cornering) while maintaining a smaller diameter in other regions. This localized dimensional change provides the necessary rigidity improvement without proportionally increasing the overall weight of the bearing assembly.
2Strength
If the number of rolling elements in the outboard row is increased, then the rigidity in the outboard region is improved, but the overall size of the bearing assembly increases
Solution Approach 1:
The patent implements local quality by increasing the number of rolling elements specifically in the outboard row (where higher rigidity is required to counteract lateral forces during cornering) while keeping the inboard row with fewer elements. This asymmetric configuration provides enhanced outboard region rigidity without proportionally increasing the overall bearing assembly size.
3Strength
If the pitch circle diameter of the outboard row is increased, then the rigidity in the outboard region is improved, but the bearing assembly occupies more space
Solution Approach 1:
The patent applies local quality by increasing the pitch circle diameter specifically for the outboard row of rolling elements (to enhance rigidity in the region subjected to lateral cornering forces) while maintaining a smaller pitch circle diameter for the inboard row. This selective configuration improves outboard region rigidity without proportionally increasing the overall space occupied by the bearing assembly.
4Strength
If the outer diameter of the hub axle is increased throughout, then the rigidity is improved, but the weight increases significantly
Solution Approach 1:
The patent resolves this contradiction by applying local quality - increasing the hub axle outer diameter only at the critical midpoint between rolling element rows where rigidity is most needed to resist moment loads, rather than uniformly increasing the diameter throughout the entire hub axle. This localized approach provides necessary rigidity improvement while minimizing weight increase.
Data Source
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AI summary
To provide a wheel support bearing assembly, in which the rigidity of an outboard portion thereof can be increased without increasing the weight of the bearing assembly, the wheel support bearing assembly includes outer and inner members (1,2) and rows Lo and Li of rolling elements (7,8) interposed between outboard and inboard raceways (3 to 6) defined in the outer and inner members confronting each other. The inner member (2) includes a hub axle (18) having a wheel fitting flange (20) on an outboard side thereof, and an inner race member (19) mounted on an inboard end thereof, The hub axle has an outer diameter D1 measured at a point P intermediate between Lo and Li is greater than the minimum diameter D2 of the raceway (6) on the inboard side, A pitch circle diameter PCDo of the outboard row Lo is greater than PCDi of the inboard row Li.