Roller Bearing Instrumented Zone Rigidity for Force Measurement

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Solution Overview

Problem

Existing rolling bearing deformation measurement techniques struggle to distinguish between variations in deformations induced by rolling bodies and average deformations caused by other factors, such as temperature, making it difficult to accurately determine forces transmitted at the wheel-roadway interface for vehicle assistance and safety systems.

Innovation Solution

A rolling bearing design with an elastically deformable circumferential surface featuring instrumented zones with higher rigidity than non-instrumented zones, where gauges, such as piezoresistive or magnetostrictive elements, are strategically placed to enhance the ratio of deformation variations to average deformations, and structural means like axial walls and slots are used to stiffen instrumented zones and soften non-instrumented zones, allowing for more precise force measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If deformation measurement is performed on the fixed ring to determine forces transmitted by the bearing, then force determination capability is improved, but measurement precision deteriorates due to small variation amplitude relative to overall deformations induced by temperature and other factors

Engineering Contradiction:
Improvedeformation measurement precisionVSAvoidforce determination reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The fixed ring is segmented into multiple zones with different rigidity characteristics. Instrumented zones with higher rigidity are created where deformation gauges are mounted, separated from non-instrumented zones by transition zones. This segmentation allows the instrumented zones to exhibit enhanced deformation variations when subjected to rolling body passage, improving the detectability of force-induced deformations against the background of temperature-induced average deformations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different zones of the fixed ring are given different local rigidity properties. The instrumented zones are designed with higher rigidity through structural features such as axial walls or increased thickness, while non-instrumented zones maintain lower rigidity. This local quality differentiation ensures that deformation measurements taken at instrumented zones are more sensitive to rolling body passage forces while being less affected by temperature-induced average deformations.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If the fixed ring is made more rigid to reduce temperature-induced deformations, then stability is improved, but deformation variations induced by rolling bodies become even smaller, worsening measurement precision

Engineering Contradiction:
Improvefixed ring stabilityVSAvoiddeformation variation detectability
Core Design Contradiction:
Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The fixed ring is divided into instrumented zones with localized high rigidity and other zones with lower rigidity. This segmentation allows the overall ring to maintain stability while specific localized areas exhibit enhanced deformation responses to rolling body passage, solving the contradiction between global stability and local measurement sensitivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Rather than making the entire fixed ring uniformly rigid, the invention applies local quality enhancement only to specific instrumented zones. These zones have increased rigidity through structural features, while other zones remain more compliant. This localized approach maintains overall stability while creating measurable deformation variations at the instrumented locations.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If structural means are added to stiffen instrumented zones, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvedeformation measurement precisionVSAvoidbearing structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The structural means for stiffening (such as axial walls or increased thickness features) are merged with the raceway structure itself rather than being added as separate components. The instrumented zones are integrated into the fixed ring geometry, combining the load-bearing function with the measurement function in a unified structure, thereby improving measurement precision without proportionally increasing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design significantly increases the ratio of deformation variations induced by rolling bodies to average deformations, improving the accuracy of force measurement and reducing the influence of non-relevant deformation sources, thereby enhancing the reliability of force determination for vehicle safety systems.

Implementation Method 1

a circumferential surface (3) which is elastically deformable by the passage of the rolling bodies

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the gauge may comprise one or more patterns based on resistive elements, in particular piezoresistive or magnetostrictive elements

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Implementation Method 3

the gauge may comprise one or more patterns based on resistive elements, in particular piezoresistive or magnetostrictive elements

Methodology Applied
Scientific EffectMagnetostriction: Magnetostriction

Data Source

PatentEP2090793B1Roller bearing with differential rigidity of zones instrumented by deformation
Publication Date: 2011.06.22 NTN SNR ROULEMENTS
  • EP2090793B1 patent drawingFigure 1~2
  • EP2090793B1 patent drawingFigure 3~5

AI summary

The bearing has a fixed outer body (1) comprising an outer surface (3) that is elastically deformable by efforts induced by the passage of rolling bodies i.e. balls, during the rotation of a rotating body. The surface has an instrumented zone (4) on which a measurement gauge for measuring the deformations is associated. The zone is circumferentially surrounded on both sides by a non instrumented zone (5), where the rigidity of the zone (4) is greater than that of the zone (5). The surface has a flange (6) comprising a fixation orifice (7) forming a fixation unit of the bearing.