Railway Wheel Orifice Sensor Offset for Contact Point

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Solution Overview

Problem

Existing railway wheel measurement technologies fail to accurately determine the lateral position of the wheel-rail contact point, especially at high speeds, and often weaken the wheel structure or are not applicable to all types of wheel tires.

Innovation Solution

A railway wheel design with strategically positioned deformation sensors offset from the neutral fiber plane in orifices, forming a Wheatstone bridge to measure vertical deformations and compensate for centrifugal forces, allowing precise determination of the lateral contact point.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If deformation sensors are mounted in the neutral fiber plane of the orifice, then the measurement is simpler, but the sensitivity to lateral position of contact point is insufficient

Engineering Contradiction:
Improvelateral position measurementVSAvoidsensor positioning complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transitions from measuring in the neutral fiber plane (2D) to measuring in a plane offset from the neutral axis by distance e (adding a third dimensional aspect). This dimensional shift enables the stress gradient measurement to capture bending components that are sensitive to lateral contact position, thereby resolving the contradiction between measurement simplicity and measurement precision.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If numerous recesses are added to the wheel rim for strain gauges, then contact point determination is possible, but the wheel structure is weakened

Engineering Contradiction:
Improvecontact point determinationVSAvoidwheel rim strength
Core Design Contradiction:
Measurement precisionVSStrength

Solution Approach 1:

Instead of adding numerous recesses throughout the wheel rim, the patent applies strain gauges locally in a specific region - within an orifice at a specific offset distance from the neutral axis. This localized measurement approach achieves contact point determination without compromising the overall structural integrity of the wheel rim.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If conventional measurement methods are used, then the setup is simpler, but accuracy at high speeds is compromised

Engineering Contradiction:
Improvehigh-speed measurement accuracyVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the measurement parameter from simple strain magnitude to stress gradient (derivative of stress with respect to position). By measuring the stress gradient at an offset location, the system captures bending components that are sensitive to lateral contact position, enabling accurate measurement at high speeds where conventional methods fail.

Inventive Principle:
Principle #35Parameter changes

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

Enables accurate measurement of the lateral position of the wheel-rail contact point, improving the determination of mechanical forces and dynamic behavior, and can be applied to standard wheels without significant structural weakening.

Implementation Method 1

at least one deformation sensor being mounted in said orifice to measure the vertical deformations during the contact of the wheel with a rail

Methodology Applied
Scientific EffectStrain measurement: Deformation

Implementation Method 2

the stress gradient inside an opening consists of a component due to compression and a component due to fabric bending. The stress gradient related to fabric bending is highly dependent on the lateral position of the contact point

Methodology Applied
Scientific EffectStress gradient:

Implementation Method 3

A railway wheel design with strategically positioned deformation sensors offset from the neutral fiber plane in orifices, forming a Wheatstone bridge to measure vertical deformations and compensate for centrifugal forces

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3072774B1Wheel and force-measurement device for a rail vehicle
Publication Date: 2020.09.23 SNCF MOBILITES
  • EP3072774B1 patent drawingFigure 1~3
  • EP3072774B1 patent drawingFigure 4~5
  • EP3072774B1 patent drawingFigure 6A~6C

AI summary

A wheel (1) for a railway vehicle, the wheel (1) comprising a web (11) in which at least one orifice (3) is formed, at least one strain sensor (4) being mounted in said orifice (3) for measuring vertical strains when the wheel (1) contacts a rail, the web comprising an inner face (A), intended to be turned towards the center of a railway track in use, and an outer face (B) opposite the inner face (A), the web (11) comprising a neutral fiber plane (N) extending in the thickness of the web (11) at an equal distance from the inner face (A) and the outer face (B) of said orifice (3), the strain sensor (4) is offset from said neutral fiber plane (N) in order to increase the sensitivity of vertical strains to the lateral position of the point of contact of the wheel (1) with said rail.