Snow Tire Kerf Structure for Uniform Block Rigidity

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Solution Overview

Problem

Conventional snow tires face challenges in maintaining optimal rigidity and friction force on both snow-covered and dry roads due to the kerf structure, which either leads to excessive block collapse or entanglement, reducing traction.

Innovation Solution

A 3D kerf structure with a wave-shaped straight portion and expansion portion, featuring unit structures with central semi-sphere holes and polygonal protrusions in opposite directions, providing alternative embossed and engraved configurations to maintain uniform block rigidity and enhance interlocking effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If kerfs are formed to provide edge effect on snow-covered roads, then gripping force is improved, but rigidity of the rubber tread block is reduced and performance on dry roads is degraded

Engineering Contradiction:
Improvegripping force on snowVSAvoidrigidity of tread block
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The kerf is divided into multiple sections (first section with slope, second section with substantially vertical side surface) with different geometric characteristics. Each section serves a specific function: the sloped first section provides cutting edge effect on snow, while the vertical second section maintains block rigidity and prevents excessive collapse.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the kerf are given different geometric properties tailored to local requirements. The first section has a slope angle of 10-70 degrees optimized for snow cutting, while the second section has a substantially vertical side surface optimized for maintaining structural integrity and controlling block collapse.

Inventive Principle:
Principle #3Local quality

2Strength

If kerf thickness is increased to maintain block rigidity, then performance on dry roads is improved, but edge effect on snow is reduced

Engineering Contradiction:
Improverigidity of tread blockVSAvoidedge effect on snow
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The kerf geometry transitions from a simple 2D cross-sectional view to a 3D structure with varying thickness along its length. The kerf is thinner at the cutting edge (first section) for snow penetration and thicker at the base (second section) for structural support, utilizing the third dimension (depth/length along the kerf) to resolve the contradiction.

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

3Strength

If small blocks of tread portion collapse excessively, then friction force from road surface is reduced, but rigidity maintenance is compromised

Engineering Contradiction:
Improverigidity of tread blockVSAvoidfriction force from road surface
Core Design Contradiction:
StrengthVSForce

Solution Approach 1:

The kerf structure is designed in advance to prevent excessive block collapse before it occurs. The substantially vertical side surface in the second section acts as a constraint that limits the degree of collapse, while the overall kerf geometry is configured to allow controlled collapse that generates friction force. This preliminary design prevents the harmful extreme of excessive collapse while maintaining the beneficial aspect of collapse-induced friction.

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP2865545B1Snow trire with a kerf structure
Publication Date: 2019.01.30 HANKOOK TIRE WORLDWIDE
  • EP2865545B1 patent drawingFigure 1~2
  • EP2865545B1 patent drawingFigure 3~4
  • EP2865545B1 patent drawingFigure 5~6

AI summary

The present invention relates to a kerf structure for a snow tire, including a wave-shaped straight portion and an expansion portion formed expanding from the straight portion, wherein the expansion portion includes unit structures, on each of which central semi-sphere holes and polygonal forms around the semi-sphere holes form protrusions in opposite directions are formed continuously. According to the present invention, the kerf structure for a snow tire provides a symmetric shape, thereby securing uniform block rigidity regardless of the direction of the kerf, and the interlocking effect can be maximized through the combination of the protrusion shape of the polygonal shape and the embossing of the semi-sphere hole. In addition, according to the present invention, the tire performance on dry roads can be ensured by optimizing the collapse of the tire tread portion and the uniform performance of the traction can be maintained until the last stages of tread wear since the polygonal shape is maintained until the last stage of the wear even though the tire is worn.