Single-Carcass-Layer Tire for Higher EV Load Without Stiffening

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Solution Overview

Problem

Existing tires struggle to carry the increased load required for electric vehicles without compromising vehicle habitability, compactness, and comfort, while also managing energy dissipation and temperature control, especially under conditions of under-inflation.

Innovation Solution

A tire design featuring a single layer of carcass reinforcement, a higher load index than standard extra-load tires, and a specific flank height and inflation pressure configuration to maintain load-carrying capacity without increasing recommended pressure, thus optimizing energy dissipation and temperature management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the tire size is increased to carry greater load, then the load-carrying capacity is improved, but the vehicle's interior space is reduced and exterior dimensions are increased

Engineering Contradiction:
Improveload-carrying capacityVSAvoidvehicle interior space
Core Design Contradiction:
StrengthVSVolume of moving object

Solution Approach 1:

The patent changes the structural parameters of the tire by implementing a single-layer carcass reinforcement with optimized cord arrangement and angles, allowing the tire to achieve higher load-carrying capacity without increasing its external dimensions. This enables the vehicle to maintain its original interior space and exterior footprint while supporting the increased weight from battery installations.

Inventive Principle:
Principle #35Parameter changes

2Strength

If the tire size is increased to carry greater load, then the load-carrying capacity is improved, but the vehicle's exterior dimensions are increased

Engineering Contradiction:
Improveload-carrying capacityVSAvoidvehicle exterior dimensions
Core Design Contradiction:
StrengthVSLength of stationary object

Solution Approach 1:

The patent modifies the internal structural parameters of the tire through a single-layer carcass design with specific cord angles and reinforcement patterns, enabling the tire to achieve higher load capacity while maintaining the same external dimensions. This allows the vehicle to support increased battery weight without expanding its exterior footprint.

Inventive Principle:
Principle #35Parameter changes

3Strength

If the recommended inflation pressure is increased to carry greater load, then the load-carrying capacity is improved, but the passenger comfort is reduced due to tire stiffening

Engineering Contradiction:
Improveload-carrying capacityVSAvoidpassenger comfort
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent changes the structural parameters by implementing a single-layer carcass reinforcement with optimized cord arrangement, allowing the tire to achieve higher load-carrying capacity at standard inflation pressures. This structural modification enables the tire to support increased loads without stiffening, thereby maintaining passenger comfort while carrying the additional battery weight.

Inventive Principle:
Principle #35Parameter changes

4Strength

If larger tires are used to carry greater load, then the load-carrying capacity is improved, but the rolling resistance and external noise are increased

Engineering Contradiction:
Improveload-carrying capacityVSAvoidrolling resistance
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The patent optimizes the structural parameters of the tire through a single-layer carcass design with specific cord angles and reinforcement patterns, enabling the tire to achieve higher load-carrying capacity without increasing its external dimensions. This prevents the increase in rolling resistance and energy loss that would otherwise result from using larger tires, while still supporting the increased vehicle weight from battery installations.

Inventive Principle:
Principle #35Parameter changes

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

The tire achieves a higher load-carrying capacity without sacrificing vehicle comfort or increasing energy dissipation and temperature, even under conditions of under-inflation, thereby addressing the challenges posed by the weight increase in electric vehicles.

Implementation Method 1

a tire comprising a crown (12), two beads (32), two sidewalls (30) connecting each bead (32) to the crown (12) and a carcass reinforcement (34) anchored in each bead (32), the carcass reinforcement (34) extending in each sidewall (30) and in the crown (12) radially internally to the crown reinforcement (16)

Methodology Applied
Scientific EffectTensile strength: Tension

Implementation Method 2

the tire having a load index LI such that LI ≥ LI'+1... the tire achieves a higher load-carrying capacity

Methodology Applied
Scientific EffectStress distribution: Deformation

Implementation Method 3

Another problem encountered by manufacturers during tire development is energy dissipation and temperature within the tire's structure... a significant increase in energy dissipation and a rise in temperature were observed

Methodology Applied
Scientific EffectEnergy dissipation: Viscoelasticity

Data Source

PatentEP4225590B1Tyre comprising a single carcass layer
Publication Date: 2025.04.23 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
  • EP4225590B1 patent drawingFigure 1
  • EP4225590B1 patent drawingFigure 2~3
  • EP4225590B1 patent drawingFigure 4

AI summary

The pneumatic tyre (11) for a passenger vehicle comprises a crown (12), two beads (32), two sidewalls (30) each connecting each bead (32) to the crown (12), and a carcass reinforcement (34) anchored in each bead (32). The pneumatic tyre (11) has a load index LI such that LI ≥ LI'+1, where LI' is the load index of an EXTRA LOAD tyre having the same dimension according to the ETRTO Standards Manual 2019. The pneumatic tyre (11) has a sidewall height H defined by H = SW x AR/100, where SW is the nominal cross-sectional width and AR is the nominal aspect ratio of the tyre according to the ETRTO Standards Manual 2019, such that H < 95. The carcass reinforcement (34) comprises a single carcass layer (36).