Wheel Bearing Geometry for Higher Rigidity at Lower Weight
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Solution Overview
Problem
Existing bearing devices for vehicle wheels, particularly in electric vehicles, face challenges in reducing weight while maintaining or enhancing rigidity, as previous designs focus on size optimization without considering the radial and axial directions effectively.
Innovation Solution
A bearing device with a specific relationship between the pitch circle diameter and inter-rolling element pitch, set as b/a≥2, optimizing the radial and axial sizes to reduce weight and improve rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the size of the bearing device is increased to enhance rigidity for electric vehicles, then the rigidity is improved, but the weight of the bearing device is increased
Solution Approach 1:
The invention changes the geometric parameters of the bearing device by setting the pitch circle diameter b of the double-row rolling elements and the inter-rolling element pitch a to satisfy b/a≥2. This parameter optimization allows the bearing to achieve enhanced rigidity through improved load distribution while avoiding weight increase from overall size enlargement
Solution Approach 2:
The invention optimizes the spatial arrangement of rolling elements by controlling the ratio between pitch circle diameter (radial dimension) and inter-rolling element pitch (axial dimension). This dimensional optimization enables the bearing to achieve rigidity enhancement without proportionally increasing weight
2Weight of moving object
If the pitch circle diameter and inter-rolling element pitch are optimized with b/a≥2, then the weight is reduced while rigidity is enhanced, but the previous design without this optimization fails to achieve further weight reduction
Solution Approach 1:
The invention introduces a specific parameter relationship (b/a≥2) between pitch circle diameter and inter-rolling element pitch to optimize the bearing structure. This parameter optimization achieves weight reduction while maintaining rigidity, resolving the limitation of previous designs that did not consider this specific geometric relationship
Data Source
AI summary
Provided is a wheel bearing device that can further reduce weight while increasing rigidity. A wheel bearing device 1 comprises: an outer ring 2 having a double row of outer raceway surfaces 23, 24; an inner member (hub ring 3 and inner ring 4) having a double row of inner raceway surfaces 33, 41 opposing the double row of outer raceway surfaces 23, 24; and double ball rows 5, 6 accommodated between both raceway surfaces of the inner member and the outer ring 2 in a manner allowing rolling. The pitch diameter b of balls 7 in the ball rows 5, 6, and the pitch a between an outer side ball 7 and an inner side ball 7 in the ball rows 5, 6 satisfy the relationship b/a≥2.0.