Pneumatic Tire Conductive Thread Structure for Breakage Resistance

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Solution Overview

Problem

Conductive threads in pneumatic tires are prone to breakage due to repeated deformation during tire operation, leading to reduced electrical conductivity and potential radio interference.

Innovation Solution

Incorporating metal filaments with a stress of 13 N or less at 1% elongation into the electroconductive threads, arranged to extend from bead portions through the tread and sidewall portions, enhances flexibility and reduces breakage risk.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electroconductive thread is used to improve conductivity, then electrical conductivity is improved, but the thread breaks due to repeated deformation during running

Engineering Contradiction:
Improveelectrical conductivityVSAvoidthread breakage resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The electroconductive thread is constructed as a composite material combining metal fibers (providing electrical conductivity) with elastic fibers such as spandex or rubber (providing flexibility and deformation resistance). This composite structure allows the thread to maintain conductivity while accommodating the repeated deformations experienced during tire operation without breaking.

Inventive Principle:
Principle #40Composite materials

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 configuration effectively suppresses thread breakage, maintains electrical conductivity, and prevents residual air during vulcanization, while ensuring low weight and corrosion resistance.

Implementation Method 1

a metal filament having a stress of 13 N or less at 1% elongation

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4155096B1Pneumatic tire
Publication Date: 2025.12.17 SUMITOMO RUBBER INDUSTRIES LTD
  • EP4155096B1 patent drawingFigure 1
  • EP4155096B1 patent drawingFigure 2
  • EP4155096B1 patent drawingFigure 3

AI summary

To provide a pneumatic tire capable of suppressing breakage of electroconductive threads. A pneumatic tire has a carcass (6). The carcass (6) includes a carcass ply (6A) having carcass cords extending from one bead portion (4) to the other bead portion (4) through a tread portion (2). At least one electroconductive thread (10) extending from the one bead portion (4) to at least the tread portion (2) is arranged on an outer surface of the carcass ply (6A). The electroconductive thread (10) includes a metal filament (11). The metal filament (11) has a stress of 13 N or less at 1% elongation.