Tyre Tread Groove Segmentation for Snow Grip

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Solution Overview

Problem

Directional tyres with main transverse grooves inclined heavily in the axial direction are poorly suited for providing effective gripping edges, particularly on snow-covered surfaces, leading to limited traction and braking performance.

Innovation Solution

Incorporating a central rib that separates two tread regions with pairs of transverse grooves having axially internal and external segments at different inclinations, where the external segment of one groove is aligned with the internal segment of the other, creating symmetrical and discordant angles to enhance traction and braking without introducing imbalances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If main transverse grooves are inclined heavily in the axial direction, then water evacuation capability is improved, but gripping edge effectiveness deteriorates

Engineering Contradiction:
Improvewater evacuationVSAvoidgrip on snow-covered surfaces
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The transverse grooves are divided into multiple segments (first, second, third segments) with different inclinations. The first segment has a first inclination, the second segment has a second inclination, and the third segment has a third inclination. This segmentation allows each segment to perform different functions: water evacuation and gripping edge provision simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different segments of the grooves have different local qualities in terms of inclination angles. The first segment is optimized for water evacuation with a steeper inclination, while the second and third segments provide gripping edges with different inclinations. This local differentiation resolves the contradiction between water evacuation and grip effectiveness.

Inventive Principle:
Principle #3Local quality

2Reliability

If transverse grooves are made with different inclinations, then traction and braking performance is improved, but tread band balance may deteriorate

Engineering Contradiction:
Improvetraction and braking performanceVSAvoidtread band balance
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The grooves feature asymmetric inclination patterns with first, second, and third segments having different inclinations. This asymmetric design provides varied gripping edges for improved traction and braking while the overall symmetric arrangement of grooves on either side of the central rib maintains tread band balance.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The groove configuration is applied symmetrically to both sides of the central rib, creating homogeneous patterns that balance the tread band. This ensures that while individual grooves have asymmetric segments for performance, the overall tread band remains balanced during rotation.

Inventive Principle:
Principle #33Homogeneity

3Reliability

If grooves are positioned closer to the equatorial plane, then gripping edge effectiveness is improved, but aquaplaning risk increases

Engineering Contradiction:
Improvegrip on icy surfacesVSAvoidaquaplaning risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The groove design extends in multiple dimensions with segments having different inclinations and orientations. By creating a three-dimensional groove structure with varying inclinations rather than simple two-dimensional grooves, the design achieves both gripping edge effectiveness near the equatorial plane and water evacuation capability to prevent aquaplaning.

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

Data Source

PatentEP3894236B1Tyre for vehicle wheels
Publication Date: 2023.08.16 PIRELLI TYRE SPA
  • EP3894236B1 patent drawingFigure 1~2

AI summary

A tyre for vehicle wheels, comprising a tread band (2) on which there are defined a first and second circumferential grooves (5, 6), delimiting a central rib (4) formed, - a first region (11) that extends from a first lateral edge (8a) of the tread band up to the first circumferential groove (5), and a second region (12) that extends substantially symmetrically to the first region from a second lateral edge (8b) of the tread band up to the second circumferential groove (6), a plurality of first pairs of corresponding transverse grooves (25) that are arranged one after the other over the circumferential extent of the first region (11), each first pair comprising a first transverse groove (30) that extends between the first lateral edge (8a) and the first circumferential groove (5) and a second transverse groove (40) that extends between the first circumferential groove (5) and the first lateral edge (8a) at an inclination that is discordant with respect to the first transverse groove (30), each first transverse groove (30) comprises a first segment (33) that extends from the first lateral edge and is inclined with respect to a circumferential direction by a first angle (A) of between 70° and 90°, and a second segment (34) that extends from the first segment (33) towards the first circumferential groove (5) and is inclined by a second angle (B) that is smaller than the first angle (A), each second transverse groove (40) comprises a first segment (42) that extends from the first circumferential groove (5) and is inclined by a third angle (C) that differs, in absolute values, from the first angle (A) by less than 15°, and a second segment (43) that extends from the first segment (42) up to the second segment (34) of the first transverse groove (30) and is inclined by a fourth angle (D) that is smaller than the third angle (C) and differs, in absolute values, from the second angle (B) by less than 15°; t he respective first ends (41) of the first transverse groove (30) and of the second transverse groove (40) are substantially aligned in an axial direction (Y) of the tyre or are at most displaced by less than 20 mm.