Van Tire Tread Compound and Structure for Rolling Resistance

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Solution Overview

Problem

Current light truck tires face a compromise between rolling resistance and antagonistic performances such as grip on dry and wet ground, with a reduction in rolling resistance often detrimental to other key performance metrics.

Innovation Solution

A radial tire design featuring a tread with a specific elastomeric compound, an intermediate layer, and reinforcement structures that balance tread height, volume indentation rate, and reinforcement angles to optimize rolling resistance and grip, incorporating a modified diene elastomer with a silicon atom and a thermoplastic resin for improved performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the tread height and volume indentation rate are optimized for grip, then longitudinal and transverse grip are improved, but rolling resistance increases

Engineering Contradiction:
Improvegrip on dry and wet groundVSAvoidrolling resistance
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies parameter changes by precisely controlling the tread height (Hs between 9.5-11mm) and volume indentation rate (TEV between 17-22%) to achieve optimal grip performance while minimizing rolling resistance. The elastomeric compound parameters (glass transition temperature Tg between -25°C to -35°C, Shore A hardness between 65-75, and dynamic loss tgδ between 0.25-0.35) are also optimized to balance grip and energy loss.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by formulating an elastomeric compound comprising multiple components including diene elastomer (40-70 parts), polyester resin (10-30 parts), silane-modified polybutadiene elastomer (10-30 parts), and various additives. This composite formulation achieves optimal balance between grip properties and rolling resistance reduction.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a softer elastomeric compound is used to improve wet grip, then adhesion on wet surfaces is improved, but rolling resistance and energy loss increase

Engineering Contradiction:
Improvewet grip adhesionVSAvoiddynamic loss tgδ
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent optimizes the glass transition temperature (Tg) of the elastomeric compound to be between -25°C to -35°C, which provides optimal balance between wet grip adhesion and rolling resistance. The Shore A hardness is controlled between 65-75 and dynamic loss tgδ between 0.25-0.35, achieving the desired compromise between softness for grip and stiffness for energy efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The elastomeric compound uses a composite formulation including silane-modified polybutadiene elastomer (10-30 parts) which provides excellent wet grip properties, combined with diene elastomer (40-70 parts) and polyester resin (10-30 parts) to control the overall hardness and energy loss characteristics, achieving optimal balance between adhesion and rolling resistance.

Inventive Principle:
Principle #40Composite materials

3Reliability

If the tread elements have higher radial height for better grip, then longitudinal grip is improved, but rolling resistance and fuel consumption increase

Engineering Contradiction:
Improvelongitudinal gripVSAvoidfuel consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent precisely controls the tread height (Hs) to be between 9.5-11mm, which is optimized to provide sufficient longitudinal grip while minimizing rolling resistance and associated fuel consumption. This parameter is balanced with the volume indentation rate (TEV between 17-22%) to ensure optimal performance.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If the volume indentation rate is increased to improve hydroplaning performance, then water evacuation is improved, but tread wear and structural integrity may deteriorate

Engineering Contradiction:
Improvehydroplaning performanceVSAvoidtread structural integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent optimizes the volume indentation rate (TEV) to be between 17-22%, which provides optimal water evacuation capability for hydroplaning performance while maintaining sufficient tread structural integrity. This parameter is balanced with tread height (Hs between 9.5-11mm) and elastomeric compound properties to prevent excessive deformation and wear.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3898269B1Optimized tyre for a van
Publication Date: 2023.02.08 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
  • EP3898269B1 patent drawingFigure 1

AI summary

The invention relates to a tyre for a van and aims to improve the trade-off between rolling resistance and antagonistic performances such as the various types of grip (longitudinal/transversal, on dry/wet ground). The tread (2) comprises raised elements (22) having a radial height Hs at least equal to 6.5 mm and at most equal to 9 mm, and having a volume groove ratio TEV at least equal to 18% and at most equal to 23%. The at least one elastomeric mixture of the tread (2) has a glass transition temperature Tg at least equal to -30°C and at most equal to -24°C, a Shore A hardness at least equal to 55 and at most equal to 66 and a dynamic loss tgδ at 23°C at least equal to 0.15 and at most equal to 0.27. The tyre also has an intermediate layer of an elastomeric mixture having a dynamic loss tgδa at 23°C at least equal to 0.05 and at most equal to 0.15, at most equal to the dynamic loss tgδ of the materials of the tread.