Tire Component Thickness and Rubber Aging for Stable Handling

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Solution Overview

Problem

Long-term maintenance of handling stability is crucial for safety, as tires degrade over time and existing technologies fail to consistently maintain handling stability after degradation.

Innovation Solution

A tire with a rubber composition that has a rate of change in elongation at break (ΔEB) of 8.0% or lower after heat aging, combined with a product (ΔEB × Tt) of less than 30, where Tt is the thickness of the tire component, to maintain handling stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional rubber compositions are used, then initial handling performance is achieved, but handling stability deteriorates after degradation

Engineering Contradiction:
Improvehandling stability after degradationVSAvoidelongation at break maintenance
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention changes the chemical composition parameters of the rubber compound by incorporating specific antioxidants (6ppd and 77pd in defined ratios) and sulfur compounds, which fundamentally alters how the rubber degrades thermally. This parameter change ensures that elongation at break remains above 40% after heat aging, directly resolving the contradiction between initial performance and long-term stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite antioxidant system combining 6ppd and 77pd with specific sulfur compounds, creating a synergistic effect that provides both initial protection and long-term stability. This composite approach allows the rubber to maintain handling stability after degradation while preserving elongation properties, resolving the technical contradiction.

Inventive Principle:
Principle #40Composite materials

2Strength

If rubber thickness is increased to improve durability, then strength is improved, but handling stability after degradation worsens due to greater cumulative degradation

Engineering Contradiction:
Improvetire component strengthVSAvoidhandling stability after degradation
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

By changing the chemical parameters of the rubber compound through specific antioxidant and sulfur compound combinations, the invention enables thinner rubber sections to achieve the same durability as thicker sections. The controlled degradation rate means that even thinner components maintain handling stability, resolving the contradiction between strength and long-term reliability.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If rubber composition is optimized for initial performance, then handling performance is improved, but degradation resistance worsens

Engineering Contradiction:
Improvehandling performanceVSAvoiddegradation resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention applies preliminary protective action by incorporating specific antioxidants (6ppd and 77pd) and sulfur compounds into the rubber compound before the tire is put into service. This preliminary protection prevents degradation from occurring rapidly, allowing the rubber to maintain both handling performance and degradation resistance throughout its service life.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention optimizes the chemical parameters of the rubber compound by defining specific ratios of antioxidants and sulfur compounds, creating a composition that simultaneously delivers excellent initial handling performance and superior degradation resistance, resolving the contradiction between these two requirements.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4566838A1tire
Publication Date: 2025.06.11 SUMITOMO RUBBER INDUSTRIES LTD
  • EP4566838A1 patent drawingFigure 1
  • EP4566838A1 patent drawingFigure 2
  • EP4566838A1 patent drawing

AI summary

Provided is a tire having excellent handling stability after degradation. The tire includes a tire component that includes a rubber composition, the rubber composition having a rate of change ΔEB in elongation at break between before and after heat aging of 8.0% or lower, the tire having a product (ΔEB × Tt) of the ΔEB (%) and a thickness Tt (mm) of the tire component of less than 30.