Tread Rubber Composition for Lightweight Tires With Wet Grip

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Solution Overview

Problem

Light-weight tires with reduced rubber volume face challenges in achieving improved wet grip performance.

Innovation Solution

A tire design with a specific ratio of tire weight to maximum load capability, utilizing a rubber composition with a tan δ of 0.15 or more and complex modulus less than 8.0 MPa, and a ratio of tan δ to tire weight of 0.016 or more, incorporating a reinforcing filler with a silica content and a resin component, to enhance wet grip performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If rubber volume is reduced to achieve light weight, then fuel efficiency is improved, but wet grip performance deteriorates

Engineering Contradiction:
Improvetire weightVSAvoidwet grip performance
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the tan δ and complex modulus of the rubber composition within specific ranges. By adjusting these viscoelastic parameters, the tire achieves optimal energy dissipation characteristics that improve wet grip performance even with reduced rubber volume, thus resolving the contradiction between light weight and wet grip performance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by formulating a specific rubber composition containing rubber components and reinforcing fillers in defined proportions. This composite structure optimizes the balance between weight reduction and performance maintenance, allowing the tire to achieve both light weight and improved wet grip performance

Inventive Principle:
Principle #40Composite materials

2Weight of moving object

If tire weight is reduced, then fuel efficiency is improved, but heat dissipation capability deteriorates

Engineering Contradiction:
Improvetire weightVSAvoidheat dissipation
Core Design Contradiction:
Weight of moving objectVSLoss of energy

Solution Approach 1:

The patent applies parameter changes by optimizing the tan δ parameter of the rubber composition. By controlling tan δ to be within a specific range, the tire enhances its ability to convert mechanical oscillation energy into thermal energy, thereby improving heat dissipation capability even with reduced tire weight

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes mechanical vibration principles by leveraging the viscoelastic properties of the rubber composition to convert high-frequency oscillations during tire operation into thermal energy. This energy conversion mechanism improves heat dissipation while maintaining light weight, resolving the contradiction between weight reduction and heat dissipation capability

Inventive Principle:
Principle #18Mechanical vibration

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 tire achieves improved wet grip performance by effectively converting high-frequency oscillations to thermal energy, promoting heat dissipation and maintaining steering stability.

Implementation Method 1

tan δ at 30°C of the rubber composition is over 0.15, and complex modulus at 30°C (E* 30) of the rubber composition is less than 8.0 MPa

Methodology Applied
Scientific EffectViscoelastic damping: Viscoelasticity

Implementation Method 2

making it possible to convert high-frequency oscillation to thermal energy, so that heat dissipation of the tread rubber is promoted

Methodology Applied
Scientific EffectHysteresis heating: Hysteresis

Data Source

PatentEP4108720B1tire
Publication Date: 2024.12.18 SUMITOMO RUBBER INDUSTRIES LTD
  • EP4108720B1 patent drawingFigure 1
  • EP4108720B1 patent drawingFigure 2
  • EP4108720B1 patent drawingFigure 3

AI summary

A tire comprising a tread part, wherein a ratio (G/WL) of a tire weight G (kg) with respect to a maximum load capability WL (kg) of the tire is 0.0131 or less, the tread comprises at least one rubber layer composed of a rubber composition comprising a rubber component and a reinforcing filler, tan δ at 30°C (30°C tan δ) of the rubber composition is over 0.15, and complex modulus at 30°C (E*30) of the rubber composition is less than 8.0 MPa, and a ratio (30°C tan δ/G) of the 30°C tan δ with respect to the G is 0.016 or more.