Composite Tire Cord Structure for Ride Comfort and Durability

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Solution Overview

Problem

The use of polyester fiber cords in tires can impair ride comfort and durability due to their higher modulus and poor compression fatigue resistance compared to nylon fiber cords, increasing the risk of breakage from repeated deformation.

Innovation Solution

A tire cord composed of twisted polyester and nylon fibers, with specified stress and elongation ranges, is used in the tire ply to maintain ride comfort and durability while reducing manufacturing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If polyester fiber cords are used instead of nylon fiber cords, then manufacturing cost is reduced, but ride comfort is impaired and compression fatigue resistance deteriorates

Engineering Contradiction:
Improvemanufacturing costVSAvoidride comfort and compression fatigue resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies composite materials by combining polyester fiber and nylon fiber in a single cord structure. The cord contains both polyester filaments and nylon filaments twisted together, creating a composite fiber cord that leverages the cost advantage of polyester while incorporating the superior mechanical properties of nylon to maintain ride comfort and compression fatigue resistance

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent specifies precise parameter ranges for the composite cord: stress at 2.5% elongation of 0.05 to 0.18 N/tex and stress at 5.0% elongation of 0.09 to 0.33 N/tex. By controlling these mechanical parameters within defined ranges, the invention optimizes the balance between cost reduction and performance maintenance

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If polyester fiber cords are used, then manufacturing cost is reduced, but strength decreases due to repeated deformation resulting in breakage

Engineering Contradiction:
Improvemanufacturing costVSAvoidcompression fatigue resistance
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The composite cord structure combines polyester and nylon fibers, where nylon provides enhanced strength and resistance to compression fatigue. This composite approach allows the cord to withstand repeated deformation without breakage while maintaining the cost benefits of polyester

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent defines specific stress and elongation parameter ranges that ensure the cord maintains sufficient strength under repeated deformation conditions. The stress at 2.5% elongation (0.05 to 0.18 N/tex) and stress at 5.0% elongation (0.09 to 0.33 N/tex) are controlled to prevent breakage while reducing cost

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

The specified tire cord configuration allows for equivalent ride comfort and durability to nylon fiber cords while reducing manufacturing costs, by optimizing elongation and stress within the 2.5% to 5.0% range.

Implementation Method 1

the cord includes a first filament made of a polyester fiber and a second filament made of a nylon fiber which are twisted together

Methodology Applied
Scientific EffectTwisting:

Data Source

PatentEP4130363B1Tire cord and tire
Publication Date: 2025.10.29 SUMITOMO RUBBER INDUSTRIES LTD
  • EP4130363B1 patent drawingFigure 1
  • EP4130363B1 patent drawingFigure 2
  • EP4130363B1 patent drawingFigure 3

AI summary

The present invention provides a tire cord and a tire capable of reducing a manufacturing cost of a tire while maintaining ride comfort and durability. The tire cord 11 is used for a ply 10 of a tire 1. The cord contains polyester fibers and has a stress σ1 at 2.5% elongation of 0.05 to 0.18 N/tex and a stress σ2 at 5.0% elongation of 0.09 to 0.33 N/tex.