Studless Tire Sipe Layout for Ice Grip and Land Rigidity

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Solution Overview

Problem

Existing pneumatic tire designs struggle to balance the rigidity of the land portion with effective water drainage and on-ice gripping performance, particularly in studless tires.

Innovation Solution

A pneumatic tire design featuring connected minute sipes on land portions, arranged in a specific configuration to form sipe units, with controlled sipe density and phase shifts, enhancing water drainage and maintaining rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If sipes are disposed at high density to improve water drainage and on-ice gripping performance, then water drainage capability is improved, but rigidity of the land portion is reduced

Engineering Contradiction:
Improvewater drainage capabilityVSAvoidrigidity of land portion
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent divides the continuous sipe structure into discrete minute sipes (first, second, and third minute sipes) with specific length ranges. This segmentation allows water drainage functionality to be distributed across multiple small openings while preserving the structural integrity of the land portion between sipes, thus resolving the contradiction between drainage capability and rigidity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different sipe configurations to different regions of the tread. Minute sipes are strategically positioned in specific land portions where water drainage is most needed, while other regions maintain higher rigidity. This localized approach allows optimization of drainage performance in critical areas without compromising overall structural strength.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If sipes are made deeper to improve on-ice gripping performance, then gripping performance is improved, but rigidity of the land portion is reduced

Engineering Contradiction:
Improveon-ice gripping performanceVSAvoidrigidity of land portion
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent implements sipes with depth of 3mm or more, which is sufficient to penetrate through typical ice layers and reach the road surface. This excessive depth ensures effective gripping performance on ice while the segmented configuration and strategic positioning prevent excessive rigidity loss in the land portion.

Inventive Principle:
Principle #16Partial or excessive action

3Object-affected harmful factors

If connected sipes are formed by connecting first, second, and third minute sipes, then water drainage path is improved, but device complexity increases

Engineering Contradiction:
Improvewater drainage pathVSAvoidsipe configuration complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent combines three separate minute sipes (first, second, and third) into a connected sipe structure where they share common endpoints. This merging creates an integrated water drainage pathway that spans across the land portion, improving drainage efficiency while the modular three-component design keeps manufacturing complexity manageable.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4424523B1Pneumatic tire
Publication Date: 2026.04.01 BRIDGESTONE CORP
  • EP4424523B1 patent drawingFigure 1
  • EP4424523B1 patent drawingFigure 2
  • EP4424523B1 patent drawingFigure 3

AI summary

Provided is a pneumatic tire in which sipe units with minute sipes are repeatedly arranged in a land portion; at least one end in an extending direction of the minute sipe of at least one of the minute sipes terminates within the land portion; w1(w2) × h is 150 (mm2) or less, and a sipe density is 0.15 (1/mm) or more.