Magnetic Sensor Calibration for Accurate Tire Tread Thickness

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Solution Overview

Problem

Existing magnetic sensors used for measuring tread thickness in tires are not accurate across tires with varying metal reinforcement densities, leading to significant measurement errors.

Innovation Solution

A method and system for adjusting a magnetic sensor to measure the distance from a metallic element in rubber-based objects by identifying an inflection point, selecting a standard response curve, and constructing a correction curve model to correct the raw response curve, allowing precise thickness measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a magnetic sensor is adjusted by connecting it to a PC via USB and using adjustment software, then the adjustment precision and ease of operation are improved, but the device complexity increases due to additional software and communication requirements

Engineering Contradiction:
Improveadjustment precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

A communication circuit is introduced as an intermediary between the control circuit and the first magnetic sensor. This communication circuit simplifies the control circuit's design by handling the USB communication protocols and data processing, thereby reducing overall device complexity while maintaining high adjustment precision through software-based control

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces manual mechanical adjustment with an automated electronic adjustment system. The control circuit automatically adjusts the magnetic sensor's operating parameters based on digital signals from the PC, eliminating the need for manual mechanical tuning mechanisms and improving both precision and ease of operation

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If the magnetic sensor is adjusted manually without automated control, then the device complexity is reduced, but the adjustment precision and time consumption are worsened

Engineering Contradiction:
Improvedevice complexityVSAvoidadjustment time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The control circuit is designed to automatically adjust the magnetic sensor without requiring manual intervention. The system performs self-diagnosis and self-adjustment based on feedback from the sensor, significantly reducing adjustment time while maintaining relatively simple device architecture through automated routines

Inventive Principle:
Principle #25Self-service

3Device complexity

If the magnetic sensor operates without temperature compensation, then the device complexity is reduced, but the measurement reliability under temperature variation is worsened

Engineering Contradiction:
Improvedevice complexityVSAvoidmeasurement reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

A temperature compensation circuit is introduced as an intermediary component that monitors temperature changes and automatically adjusts the magnetic sensor's operating parameters to compensate for thermal effects. This maintains measurement reliability across temperature variations while adding minimal complexity through a dedicated compensation module

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements temperature feedback control where the temperature compensation circuit continuously monitors the magnetic sensor's operating temperature and adjusts bias currents or other parameters in real-time to maintain optimal performance. This feedback mechanism ensures reliable measurements under varying temperature conditions without requiring complex redesign

Inventive Principle:
Principle #23Feedback

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 precise measurement of rubber layer thickness and efficient recycling or retreading by ensuring the magnetic sensor is calibrated for different tire constructions, reducing measurement errors and enabling safe machining near metallic elements.

Implementation Method 1

a first magnetic sensor arranged to detect a position of the movable component

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Implementation Method 2

a second magnetic sensor arranged to detect a position of the movable component

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Implementation Method 3

a magnetic circuit having a movable component

Methodology Applied
Scientific EffectMagnetic circuit: Magnetic Field

Data Source

PatentEP4591027B1Method for adjusting a magnetic sensor
Publication Date: 2026.05.20 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
  • EP4591027B1 patent drawingFigure 1~2
  • EP4591027B1 patent drawingFigure 3
  • EP4591027B1 patent drawingFigure 4

AI summary

A method for adjusting a magnetic sensor (6) configured to provide, as a response signal, a measurement of a distance that separates said magnetic sensor (6) from a metal element (4) located in a rubber-based object (1), such as a metal reinforcing element (4) present in a pneumatic tyre, said method comprising: - a step (a) of acquiring a first curve, referred to as "raw response curve", during which the magnetic sensor (6) is successively placed at different positions relative to the object (1) so that said magnetic sensor (6) is successively located at different corresponding distances from the metal element (4), and, in each of said positions, the response signal returned by said magnetic sensor (6) is collected, so as to obtain a raw response curve which represents the evolution of the response signal of the magnetic sensor (6) as a function of the distance separating said sensor from the metal element (4), - a step (b) of determining, from the raw response curve, a correction curve model, - a correction step (c), during which a second curve, referred to as "corrected response curve", is established, by correcting the raw response curve on the basis of the correction curve model.