Tire Tread Profiles for Wear and Stability

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Solution Overview

Problem

Tires with tread portions having a designated mounting direction face issues with low wear resistance and steering stability, particularly at the outermost tread surface when mounted on a vehicle.

Innovation Solution

The tire design includes an outer tread edge with an outer shoulder main groove and land portion featuring specific circular arc profiles and lateral grooves, which distribute contact pressure uniformly, enhancing wear resistance and steering stability by minimizing local pressure on the tread surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a tire has a tread portion with a designated mounting direction, then steering stability on dry and wet road surfaces is improved, but wear resistance at the outermost tread surface is low

Engineering Contradiction:
Improvesteering stabilityVSAvoidwear resistance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent applies different radius of curvature values to different regions of the tread surface. The outer shoulder land portion has a smaller radius of curvature (R1) compared to the outer middle land portion (R2), creating local variation in surface geometry. This local quality differentiation allows the outer shoulder region to have enhanced wear resistance while maintaining the overall steering stability provided by the directed mounting tread design.

Inventive Principle:
Principle #3Local quality

2Stress or pressure

If the tread portion has a profile curved convexly outward, then contact pressure distribution is improved, but wear resistance at the outer shoulder land portion remains insufficient

Engineering Contradiction:
Improvecontact pressure distributionVSAvoidwear resistance
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The patent introduces a local quality variation by specifying different radius of curvature values for different tread regions. The outer shoulder land portion (R1) has a smaller radius than the outer middle land portion (R2), creating a localized geometric feature that enhances wear resistance in the high-stress outer shoulder area while preserving the overall convex curved profile for good contact pressure distribution.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3785940B1tire
Publication Date: 2022.01.19 SUMITOMO RUBBER INDUSTRIES LTD
  • EP3785940B1 patent drawingFigure 1
  • EP3785940B1 patent drawingFigure 2
  • EP3785940B1 patent drawingFigure 3

AI summary

A tire that can exhibit excellent steering stability and wet performance is provided; a tread portion (2) includes an outer tread edge To, an outer shoulder main groove (5), an outer shoulder land portion (8), and an outer middle land portion (9); a tread surface of the outer middle land portion (9) includes a first profile (16) composed of a circular arc having a radius of curvature R1; a tread surface of the outer shoulder land portion (8) includes a second profile (17) composed of a circular arc having a radius of curvature R2, and a third profile (18) extending from an inner end in a tire axial direction of the second profile (17) to a groove edge of the outer shoulder main groove (5) and composed of a circular arc having a radius of curvature R3 smaller than the radius of curvature R2.