Tyre Groove Protrusions for Stone Ejection and Fatigue Resistance

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Solution Overview

Problem

Tyres designed for urban and suburban use face issues with stone entrapping in grooves, leading to 'stone drilling' and material tearing when driving on unmade or partially asphalt-paved roads, as existing protrusions do not provide sufficient surface area for stone ejection and can compromise tyre fatigue resistance.

Innovation Solution

The tyre features protruding elements with a smaller base size at the groove bottom and a larger top surface, allowing for increased contact area and flexibility, enabling efficient stone ejection and reduced fatigue risk by providing a wide rest surface and lateral bending mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If protrusions are made with constant section or tapering towards the upper end, then stone ejection capability is improved, but the connecting radii between side walls and groove bottom must be decreased, worsening fatigue resistance

Engineering Contradiction:
Improvestone entrappingVSAvoidfatigue resistance
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The protrusion features an asymmetric cross-section that is larger at the top and smaller at the base, allowing the top surface to effectively contact and eject stones while the reduced base area maintains adequate connecting radii with groove bottom side walls, thus preserving fatigue resistance

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The protrusion is designed with non-uniform cross-sectional area along its height, providing a larger surface area at the top for stone ejection functionality while maintaining smaller dimensions at the base to preserve structural integrity and fatigue resistance in the groove region

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If protrusions are made with larger top surfaces for stone ejection, then stone ejection efficiency is improved, but the space between the base of protrusion and side walls of groove is reduced, compromising tyre strength

Engineering Contradiction:
Improvestone entrappingVSAvoidtyre strength
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The protrusion features an asymmetric cross-section that is larger at the top and smaller at the base, allowing the top surface to effectively contact and eject stones while the reduced base area maintains adequate connecting radii with groove bottom side walls, thus preserving fatigue resistance

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The protrusion is designed with non-uniform cross-sectional area along its height, providing a larger surface area at the top for stone ejection functionality while maintaining smaller dimensions at the base to preserve structural integrity and fatigue resistance in the groove region

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design effectively prevents stone entrapping, reduces the risk of material tearing, and optimizes traction, grip, and drainage performance on unmade roads while maintaining tyre strength and flexibility.

Implementation Method 1

the protruding stripe is deflected as a whole, thereby generating a reaction force on the basis of a deformation restoring force

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the top head portion is inclined around the base portion, and the protruding stripe is deflected as a whole

Methodology Applied
Scientific EffectDeformation: Deformation

Implementation Method 3

during rolling, the centrifugal force by itself is not able to eject them

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2344350B1Tyre for vehicle wheels
Publication Date: 2013.01.02 PIRELLI TYRE SPA
  • EP2344350B1 patent drawingFigure 1
  • EP2344350B1 patent drawingFigure 2
  • EP2344350B1 patent drawingFigure 3~6

AI summary

A tyre for vehicle wheels comprises a tread band (4) having a plurality of grooves (9) and including a plurality of elements protruding from a bottom surface (15) of the grooves (9). The protruding elements (18) have a height (h) less extended than a depth (H) of the grooves (9) and each of the protruding elements (18) has a proximal portion (20) placed close to the bottom surface (15) that is smaller than a distal portion (18a) thereof. The protruding element (18) comprises a stem (21) linked to the bottom surface (15), and two tailpieces (22) extending in mutually opposite directions from a distal end of the stem (21).