Rubber Tread Composition for High-Load Fuel-Efficient Tires

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Solution Overview

Problem

Existing tires face limitations in improving comfortability and fuel efficiency, particularly under high-load conditions, as reducing tire cross-sectional width alone is insufficient, and there is a need for enhanced performance in vehicles with increased load capacity.

Innovation Solution

A tire design with a tire outer diameter of 600 mm or less, utilizing a rubber composition that includes specific parameters such as tire cross-sectional width, tan δ at 30°C, total styrene amount, and isoprene-based rubber content, along with fillers like silica, to optimize fuel efficiency during high-load running.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If tire cross-sectional width is reduced to improve comfortability, then vehicle space is improved, but fuel efficiency under high-load conditions deteriorates

Engineering Contradiction:
Improvevehicle spaceVSAvoidfuel efficiency
Core Design Contradiction:
Volume of moving objectVSUse of energy by moving object

Solution Approach 1:

The patent changes the chemical composition parameters of the rubber material by controlling the styrene content (10-30%) and isoprene-based rubber content (25% or less) to optimize the tan δ at 30°C, thereby improving fuel efficiency under high-load conditions while maintaining acceptable comfortability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite rubber composition combining styrene-butadiene rubber with isoprene-based rubber and specific fillers (silica, carbon black) to achieve optimal balance between comfortability and fuel efficiency, where the composite material properties are tuned through controlled composition ratios

Inventive Principle:
Principle #40Composite materials

2Volume of moving object

If tire cross-sectional width is reduced to improve comfortability, then wheelhouse space is optimized, but heat generation under high-load conditions increases

Engineering Contradiction:
Improvewheelhouse spaceVSAvoidheat generation
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The patent controls the tan δ at 30°C within a specific range (0.08-0.15) by adjusting rubber composition parameters, which directly reduces heat generation during high-load operation while maintaining compact tire dimensions for optimized wheelhouse space

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If rubber composition is modified to improve fuel efficiency, then energy consumption is reduced, but tire deformation control becomes more difficult

Engineering Contradiction:
Improveenergy consumptionVSAvoidtire deformation control
Core Design Contradiction:
Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent optimizes the rubber composition by controlling styrene content (10-30%) and isoprene-based rubber content (25% or less) to achieve a tan δ at 30°C of 0.08-0.15, which reduces energy consumption while the filler system (silica, carbon black) maintains structural stability and deformation control

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 tire design effectively suppresses heat generation and deformation, leading to improved fuel efficiency and comfortability by balancing tire dimensions and composition, enhancing performance under high-load conditions.

Implementation Method 1

a tan δ at 30°C (30°C tan δ) of the rubber composition satisfy the following inequality (1)

Methodology Applied
Scientific Effecttan δ (loss tangent): Viscoelasticity

Data Source

PatentEP4389459B1tire
Publication Date: 2026.03.18 SUMITOMO RUBBER INDUSTRIES LTD
  • EP4389459B1 patent drawingFigure 1
  • EP4389459B1 patent drawingFigure 2
  • EP4389459B1 patent drawing

AI summary

It is an object of the present invention to provide a tire having improved fuel efficiency during high-load running. Provided is a tire comprising a tread part, wherein a tire outer diameter Dt is 600 mm or less, wherein the tread part is composed of a rubber composition comprising a rubber component and a filler, and wherein a tire cross-sectional width Wt, in mm, and a tan δ at 30°C (30°C tan δ) of the rubber composition satisfy the following inequality (1): 30°Ctanδ≦−7.84×10−5×Wt−1952+0.175