Multi-layer Tread Band with Revealed Grooves for Wet Grip

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Solution Overview

Problem

Tyre tread bands face challenges in maintaining grip and reducing rolling resistance throughout their lifespan, as wear leads to decreased hollow volume in grooves, affecting drainage and traction, while conventional thickness adjustments impact hysteresis and thermal losses.

Innovation Solution

A tyre tread band design featuring multiple wearing layers with circumferential grooves and transverse incisions, where the first layer provides initial contact and the second layer with channels and holes enhances drainage and traction after wear, reducing compressibility and energy dissipation, and maintaining performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If the thickness of the tread band is increased to provide more material for wear, then the distance the tyre can cover before replacement is increased, but hysteresis losses and rolling resistance increase

Engineering Contradiction:

Improvedistance covered before replacementVSAvoidhysteresis losses and rolling resistance

Core Design Contradiction:

Duration of action of moving objectVSLoss of energy

Solution Approach 1:

The tread band is divided into multiple wearing layers (first wearing layer, second wearing layer, and optionally third wearing layer) with different functions. The first layer provides initial contact and drainage, while subsequent layers are revealed after wear and provide continued drainage and grip. This segmentation allows optimization of each layer's thickness and composition to balance durability and energy efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The tread structure transitions dynamically as wear progresses. Initially, the first wearing layer with circumferential grooves provides drainage. As this layer wears away, the second wearing layer with channels and transverse incisions is revealed, maintaining drainage capability. This dynamic revelation of different layers ensures consistent performance throughout the tyre's lifespan while allowing thinner overall construction.

Inventive Principle:

Principle #15Dynamics

2Loss of energy

If the thickness of the tread band is reduced to increase stiffness and reduce thermal losses, then hysteresis losses are reduced, but the tyre may wear out faster

Engineering Contradiction:

Improvethermal losses through hysteresisVSAvoidservice life of the tyre

Core Design Contradiction:

Loss of energyVSDuration of action of moving object

Solution Approach 1:

Different wearing layers have different local qualities optimized for their specific functions. The first wearing layer is optimized for initial contact and water drainage with circumferential grooves. The second wearing layer, revealed after wear, has channels and transverse incisions optimized for maintaining drainage and grip as the tyre ages. This allows thinner overall construction with reduced hysteresis while maintaining durability through functional differentiation.

Inventive Principle:

Principle #3Local quality

3Reliability

If the hollow volume of grooves is maintained to ensure good drainage on wet roads, then drainage performance is improved, but the tread band thickness must be increased which increases rolling resistance

Engineering Contradiction:

Improvedrainage performance on wet roadsVSAvoidrolling resistance

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The drainage system is extended into the depth dimension with multiple wearing layers containing grooves, channels, and incisions at different depths. The first wearing layer has circumferential grooves for initial drainage. The second wearing layer, revealed after wear, has channels and transverse incisions that create additional drainage pathways. This multi-level approach maintains drainage performance without requiring excessive tread thickness, as the drainage capability is distributed through the depth of the tread structure.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

4Reliability

If transverse incisions are added to create additional edges for grip, then traction is improved, but the complexity of the tread structure increases

Engineering Contradiction:

Improvetraction and gripVSAvoidtread structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The transverse incisions are pre-formed in the second wearing layer during manufacturing, but they remain closed or covered during the initial service period when the first wearing layer is active. As the first layer wears away, these incisions are automatically revealed, providing additional edges and improved grip at the appropriate time. This preliminary preparation of the incisions simplifies the manufacturing process while ensuring the complexity is only introduced when needed for enhanced traction.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8939183B2Tread with an improved drainage space

Publication Date: 2015.01.27 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)

AI summary

Tire tread band having a tread surface having at least two wearing layers, a first wearing layer formed by raised elements each having a contact surface, having at least grooves of circumferential orientation, and intended to contact the road surface when new, and at least one wearing layer in contact with the road surface after the first layer has entirely worn away, and containing at least one channel extending in the circumferential direction, and opening onto the tread surface when the wearing layer that precedes it has completely worn away, each wearing layer distinct from the first wearing layer, having transverse incisions distributed in the circumferential direction, extending from a channel of the layer in a direction which is not circumferential, opening fully or partially into at least one other circumferentially oriented channel or groove, irrespective of the level of wear of the other wearing layer.