Co-Crosslinked Elastomer Piezoelectric Stack for Tire Shock Detection

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Solution Overview

Problem

Current piezoelectric composites used in tires lack the mechanical properties necessary for integration into tire structures, particularly resistance to deformation and elongation, while also requiring enhanced electroactive properties for energy generation and shock detection.

Innovation Solution

A device comprising a piezoelectric composite layer sandwiched between two conductive composite layers, where the piezoelectric composite is based on a rubber composition with over 50 parts by weight of elastomer, diene elastomer, a crosslinking system, and piezoelectric inorganic fillers, and the conductive composite layers are based on diene elastomer, conductive fillers, with the diene elastomers co-crosslinked for improved cohesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If piezoelectric composites are used in tires, then energy generation and shock detection capabilities are improved, but mechanical properties such as resistance to deformation and elongation are insufficient

Engineering Contradiction:
Improveenergy generationVSAvoidresistance to deformation
Core Design Contradiction:
Use of energy by moving objectVSStrength

Solution Approach 1:

The patent employs a composite material system consisting of a piezoelectric layer containing piezoelectric particles dispersed in an elastomeric matrix, combined with conductive layers. This composite structure allows the device to simultaneously achieve piezoelectric functionality for energy generation and the mechanical flexibility required for tire integration, resolving the contradiction between functional performance and mechanical strength.

Inventive Principle:
Principle #40Composite materials

2Use of energy by moving object

If piezoelectric composites are used in tires, then energy generation and shock detection capabilities are improved, but resistance to elongation is insufficient

Engineering Contradiction:
Improveenergy generationVSAvoidresistance to elongation
Core Design Contradiction:
Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent utilizes flexible elastomeric matrices to encapsulate the piezoelectric particles, creating a thin film structure that can withstand elongation and deformation typical of tire applications. The elastomeric nature of the matrix provides the necessary flexibility and elasticity, allowing the device to maintain its piezoelectric properties while accommodating the dynamic mechanical environment of the tire.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If piezoelectric composites are integrated into tire, then tire monitoring and impact detection are improved, but integration compatibility with tire materials is challenging

Engineering Contradiction:
Improvetire monitoringVSAvoidintegration compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent achieves integration compatibility by using elastomeric matrices in the piezoelectric device that are chemically and mechanically similar to common tire materials. This homogeneity in material composition allows for seamless integration into the tire structure, enabling reliable tire monitoring and impact detection without creating material incompatibility issues.

Inventive Principle:
Principle #33Homogeneity

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

The solution provides a flexible and elastic device with enhanced piezoelectric properties, allowing for effective energy generation and shock detection within the tire, while maintaining mechanical integrity and compatibility with tire materials.

Implementation Method 1

Piezoelectricity develops in materials such as crystals, certain semi-crystalline polymers, and piezoelectric ceramics. This physical phenomenon corresponds to the appearance of an electrical polarization induced by external mechanical deformation.

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the diene elastomer of the P layer being co-crosslinked with the diene elastomer of each E layer

Methodology Applied
Scientific EffectCo-crosslinking: Chemical Bonding

Data Source

PatentEP3811424B1Device consisting of an elastomer matrix, comprising piezoelectric charges and electrodes
Publication Date: 2024.05.29 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
  • EP3811424B1 patent drawingFigure 1~2
  • EP3811424B1 patent drawingFigure 3
  • EP3811424B1 patent drawing

AI summary

The invention relates to a piezoelectric device comprising at least one piezoelectric composite layer P inserted between two conductive composite layers E, each layer E forming an electrode, characterised in that: the layer P is a rubber composition containing more than 50 parts by weight per hundred parts by weight rubber, phr, of diene elastomer, a cross-linking system and at least 5 vol. %, in relation to the total volume of the rubber composition, of piezoelectric inorganic charges; and each layer E is a rubber composition containing at least 50 phr of diene elastomer, a cross-linking system, and conductive charges. The invention also relates to a method for producing said device and to a tyre comprising said device.