Tire Sipe Structure for Cornering Grip Under Tread Wear

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Solution Overview

Problem

Tires with existing sipe structures face degradation in on-ice/snow and wet performance during cornering due to increased stiffness of the land portion with tread wear, leading to reduced edge effect and compromised cornering capabilities.

Innovation Solution

The tire design incorporates an outer sipe element extending in the tire axial direction and a plurality of inner sipe elements extending in the tire circumferential direction, with bent elements featuring offset and terminating elements that connect and overlap, maintaining stiffness and enhancing edge effect even as the tread wears, thereby improving cornering performance on ice/snow and wet surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a conventional sipe structure without circumferential components is used, then the structure is simple, but stiffness of the land portion in the tire axial direction increases with tread wear, reducing edge effect and cornering performance

Engineering Contradiction:
Improvesipe structureVSAvoidcornering performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The sipe is divided into multiple segments including a circumferential component and multiple inclined components. This segmentation allows each segment to perform specific functions: the circumferential component maintains land portion flexibility in the axial direction to preserve edge effect during cornering, while the inclined components provide cutting edges for snow/ice penetration. The segmented structure prevents the entire sipe from becoming rigid as tread wears.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention adds a circumferential dimension component to the traditional axial-oriented sipe structure. By incorporating a component extending in the tire circumferential direction, the sipe gains the ability to maintain flexibility in the axial direction while still providing effective cutting edges. This dimensional addition resolves the contradiction between structural simplicity and cornering performance reliability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Strength

If the land portion becomes stiff due to tread wear, then structural integrity is maintained, but edge effect during cornering decreases, degrading on-ice/snow and wet performance

Engineering Contradiction:
Improveland portion integrityVSAvoidedge effect
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The sipe structure implements local quality differentiation through its multi-component design. The circumferential component specifically addresses the need for flexibility in the axial direction to maintain edge effect, while the inclined components locally provide cutting functionality. This localized functional distribution allows different parts of the sipe to address different requirements, preventing uniform rigidity that would harm cornering performance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sipe structure is designed to dynamically adapt to tread wear. As the tread portion wears, the inclined components gradually become more prominent while the circumferential component continues to maintain land portion flexibility. This dynamic evolution ensures that edge effect is preserved throughout the tire's service life, transitioning from initial acceleration/deceleration performance to sustained cornering performance as tread wears.

Inventive Principle:
Principle #15Dynamics

3Reliability

If inclined portions are added to the sipe to maintain edge effect, then cornering performance is improved, but the sipe structure becomes more complex

Engineering Contradiction:
Improvecornering performanceVSAvoidsipe structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges multiple functional components into a single integrated sipe structure. The circumferential component and multiple inclined components are combined within one sipe, allowing them to work together synergistically. This merging approach achieves improved cornering performance through the coordinated action of different components while avoiding the complexity of multiple separate features, as all elements are unified within the single sipe structure.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4238784B1tire
Publication Date: 2025.01.15 SUMITOMO RUBBER INDUSTRIES LTD
  • EP4238784B1 patent drawingFigure 1
  • EP4238784B1 patent drawingFigure 2
  • EP4238784B1 patent drawingFigure 3

AI summary

A tread portion of a tire includes at least one land portion 4. The land portion 4 includes an outer region 41 disposed inwardly of a tread surface 40 in a tire radial direction, an inner region 42 disposed on an inner side in the tire radial direction, and at least one sipe 5. The sipe 5 includes one outer sipe element 51 extending in the outer region 41 in a tire axial direction, and a plurality of inner sipe elements 52 extending in the inner region 42. The inner sipe elements 52 include a component 52A extending in a tire circumferential direction, and is connected to the outer sipe element 51.