Winter Tyre Sipe Structure for Stiffness Without Mould Tearing

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Solution Overview

Problem

Existing winter tyres with complex type sipes face issues of increased manufacturing complexity due to large interference surfaces, leading to tearing during moulding, and reduced snow retention due to excessive stiffness, which affects performance on snowy and dry/wet road surfaces.

Innovation Solution

A tyre design featuring complex type sipes with alternating recesses and protrusions along the longitudinal sipe development, configured to maximize interference surface area while minimizing block deformation, ensuring high stiffness without compromising snow retention and manufacturing ease.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex type sipes with large interference surfaces are provided on blocks, then tyre performance on dry or wet road surfaces is improved due to increased block stiffness, but manufacturing complexity increases and tearing during moulding occurs

Engineering Contradiction:
Improvetyre performance on dry or wet road surfacesVSAvoidmanufacturing complexity and tearing during moulding
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies local quality by creating specific geometric features (protrusions and recesses) at localized positions within the sipe structure. The radial profiles include coupling portions with protrusions on one block portion and corresponding recesses on the other, concentrating the interference function at specific locations rather than requiring large overall interference surfaces. This localized geometric design provides the necessary stiffness while reducing manufacturing complexity.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If simple type sipes are provided on blocks, then manufacturing is simplified and snow retention is maintained, but tyre performance on dry or wet road surfaces deteriorates due to reduced block stiffness

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidperformance on dry or wet road surfaces
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces localized geometric features (protrusions and recesses with specific radial profiles) within otherwise simple sipe structures. This approach maintains the overall simplicity of the sipe design for easy manufacturing while adding local complexity only where interference is needed to provide block stiffness for dry/wet road performance.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4452671B1Winter tyre
Publication Date: 2026.02.18 PIRELLI TYRE SPA
  • EP4452671B1 patent drawingFigure 1~5
  • EP4452671B1 patent drawingFigure 6~7
  • EP4452671B1 patent drawingFigure 8~10

AI summary

A tyre (1) comprises at least one block (8) on which at least one complex type sipe (10) is obtained separating the block (8) into two portions (11, 2) comprising a first surface (13) and a second surface (14) respectively facing each other. The first surface (13) is extended between a set of first and second longitudinal sections (17, 18) having, respectively, a first and a second radial profile (20, 21), which are symmetrical to each other, each one comprising a coupling portion between the two block portions (11, 12) formed by a protrusion (25; 31) and a recess (26; 30) defined by three consecutive inclined lengths (27, 28, 29; 32, 33, 34), the pattern of which is such that the ends (23, 24) of the coupling portion are offset from each other along a direction transverse to the longitudinal direction of the sipe.