Tread Rubber and Groove Layout for Dry-Road Tire Grip

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Solution Overview

Problem

Pneumatic tires face challenges in achieving high initial and peak grip performance on dry road surfaces, as existing tire designs struggle to balance tread deformation, heat generation, and grip effectiveness.

Innovation Solution

A tire design with a land ratio of 0.50 to 0.80 on the grounding surface and a specific average loss tangent value of the tread rubber between 0.40 to 0.60, combined with a tread pattern featuring circumferential grooves and width direction grooves, enhances grip performance by allowing for better deformation and heat generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the land ratio is increased to improve initial grip performance, then the contact area with the road surface increases, but the heat generation capability decreases

Engineering Contradiction:
Improveinitial grip performanceVSAvoidheat generation capability
Core Design Contradiction:
ForceVSTemperature

Solution Approach 1:

The patent optimizes the land ratio parameter to a specific range (0.55 ≤ R < 0.85) to balance the conflicting requirements of initial grip performance and heat generation capability. This parameter change resolves the contradiction by finding the optimal intermediate value that satisfies both conditions simultaneously.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If the land ratio is decreased to improve heat generation, then the tread can warm up faster, but the initial grip performance deteriorates

Engineering Contradiction:
Improveheat generationVSAvoidinitial grip performance
Core Design Contradiction:
TemperatureVSForce

Solution Approach 1:

The patent establishes a lower bound (0.55) for the land ratio parameter to ensure sufficient initial grip performance while allowing enough exposed tread area for heat generation. This parameter setting resolves the contradiction by preventing the land ratio from becoming too small.

Inventive Principle:
Principle #35Parameter changes

3Force

If more grooves are added to the tread pattern, then the heat generation and grip performance are improved, but the structural complexity increases

Engineering Contradiction:
Improvegrip performanceVSAvoidtread pattern complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent divides the tread into multiple land parts separated by grooves, with each land part having specific characteristics. This segmentation allows the tread to generate heat effectively while maintaining manageable structural complexity through systematic arrangement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent assigns different properties to different land parts (shoulder land parts vs. center land parts) based on their positions and functions. This local quality approach optimizes grip performance in different regions without uniformly increasing overall complexity.

Inventive Principle:
Principle #3Local quality

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 exhibits improved initial and peak grip performance on dry road surfaces due to optimized tread deformation and heat generation, maintaining effective grip throughout the tire's lifespan.

Implementation Method 1

an average value tan δA of a loss tangent tan δ of the rubber composition at -15°C to 20°C... is 0.40 to 0.60

Methodology Applied
Scientific EffectViscoelastic heating: Viscoelasticity

Data Source

PatentEP4169739B1tire
Publication Date: 2024.07.31 SUMITOMO RUBBER INDUSTRIES LTD
  • EP4169739B1 patent drawingFigure 1
  • EP4169739B1 patent drawingFigure 2
  • EP4169739B1 patent drawing

AI summary

An object of the present disclosure is to provide a tire having improved overall performance of an initial grip performance and a peak grip performance on a dry road surface. Provided is a tire comprising a tread part, the tread part having two or more circumferential grooves extending continuously in a tire circumferential direction, a pair of shoulder land parts partitioned by the circumferential grooves and grounding ends, a center land part located between the pair of shoulder land parts, and a width direction groove, wherein a land ratio R on a grounding surface of the tread part is 0.50 to 0.80, wherein the tread part has at least one rubber layer consisting of a rubber composition comprising a rubber component, and wherein an average value tan δA of a loss tangent tan δ of the rubber composition at -15°C to 20°C, measured under a condition of a frequency of 10 Hz, an initial strain of 0.1%, and a dynamic strain amplitude of ± 0.25%, is 0.40 to 0.60.