Tyre Bead Polymer Layer Layout for Low Rolling Resistance

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Solution Overview

Problem

Heavy-duty tires face issues with bead area durability, wear performance, and rolling resistance, particularly under severe load and inflation pressure conditions, especially when designed with reduced weight and recessed bead areas.

Innovation Solution

A tire design featuring a radial carcass reinforcement with specific polymeric mixture layers in the bead area, including a sixth layer with high linearity and low deformation properties, combined with a carcass reinforcement layer anchored by stiffening elements, enhances bead area endurance and rolling resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the bead area is reduced in thickness and weight, then the tire weight is reduced, but the rolling resistance performance deteriorates under severe load and inflation pressure conditions

Engineering Contradiction:
Improvetire weightVSAvoidrolling resistance
Core Design Contradiction:
Weight of moving objectVSLoss of energy

Solution Approach 1:

The patent applies local quality by implementing a recessed bead area configuration where only specific regions (the bead core area) are reduced in thickness, while the surrounding tread and sidewall areas maintain their conventional thickness. This localized thinning reduces overall tire weight without compromising the rolling resistance performance of the contact patch, thereby resolving the contradiction between weight reduction and energy loss.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes composite materials by combining the recessed bead area structure with reinforced cord layers and specialized rubber compounds in the bead region. This composite approach allows the tire to maintain structural integrity and optimal rolling resistance characteristics in the contact area while achieving weight reduction through the recessed configuration, thus balancing weight reduction with energy efficiency.

Inventive Principle:
Principle #40Composite materials

2Weight of moving object

If the bead area is reduced in thickness, then the tire weight is reduced, but the bead area durability and wear performance deteriorate under extreme conditions

Engineering Contradiction:
Improvetire weightVSAvoidbead area durability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent applies local quality by implementing a recessed bead area configuration where only specific regions (the bead core area) are reduced in thickness, while the surrounding tread and sidewall areas maintain their conventional thickness. This localized thinning reduces overall tire weight without compromising the rolling resistance performance of the contact patch, thereby resolving the contradiction between weight reduction and energy loss.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs beforehand cushioning by strategically positioning reinforced cord layers and high-durability rubber compounds in the bead area before the tire encounters extreme conditions. This preventive reinforcement ensures that the bead region maintains its structural integrity and durability under severe loads and inflation pressures, compensating for the reduced thickness of the recessed bead area.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Weight of moving object

If recessed bead area design is implemented, then tire weight is reduced, but bead area integrity under extreme load and pressure conditions is compromised

Engineering Contradiction:
Improvetire weightVSAvoidbead area integrity
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent applies local quality by implementing a recessed bead area configuration where only specific regions (the bead core area) are reduced in thickness, while the surrounding tread and sidewall areas maintain their conventional thickness. This localized thinning reduces overall tire weight without compromising the rolling resistance performance of the contact patch, thereby resolving the contradiction between weight reduction and energy loss.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes composite materials by combining the recessed bead area structure with reinforced cord layers and specialized rubber compounds in the bead region. This composite approach allows the tire to maintain structural integrity and optimal rolling resistance characteristics in the contact area while achieving weight reduction through the recessed configuration, thus balancing weight reduction with energy efficiency.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP4436797B1Tyre with improved rolling resistance performance
Publication Date: 2026.01.21 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
  • EP4436797B1 patent drawingFigure 1
  • EP4436797B1 patent drawingFigure 2
  • EP4436797B1 patent drawingFigure 3

AI summary

The invention relates to a tyre having a radial carcass reinforcement formed by a single layer of reinforcing elements which is anchored in each of the beads, being turned up around a bead wire, and reinforced by a stiffener. According to the invention, a sixth layer of one or more polymer blends (21) is disposed axially between the sidewall and the carcass reinforcement, the maximum tan(δ) value of the sixth layer of one or more polymer blends (21), denoted tan(δ)max, measured at 60° C, being less than 0.050 and the linearity ratio of the dynamic complex shear modulus G* of the sixth layer of one or more polymer blends (21), at a temperature of 23° C, being greater than 0.80.