Tyre Sidewall Profile Design for Curb Impact Resistance

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Heavy-duty vehicle tires are prone to damage and premature wear when contacting curbs due to their thick bead zone design, which increases fragility and susceptibility to shocks and friction.

Innovation Solution

A tire design featuring a radial carcass reinforcement with a single layer of reinforcing elements anchored in the bead zone, a modified meridian section profile that extends the outer surface with a constant thickness, and a hollow rim of the '15° drop center' type, reducing the bead zone's thickness and enhancing deformation homogeneity during curb contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the bead zone is thickened to protect against curb contact, then the tire's resistance to shocks and friction improves, but the tire's fragility and susceptibility to damage increases

Engineering Contradiction:
Improveresistance to curb contact damageVSAvoidsusceptibility to shocks and friction
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies local quality by providing targeted reinforcement at the bead zone through a specific structural configuration: a single layer of carcass reinforcement anchored at the beads, combined with a crown reinforcement of at least two layers forming angles of 10° to 45° with the circumferential direction. This localized structural design strengthens the bead zone specifically for curb contact protection while avoiding unnecessary thickening that would increase overall fragility.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining different reinforcement elements: the carcass reinforcement layer (single layer anchored at beads) working in conjunction with the crown reinforcement (multiple layers at specific angles). This composite structure creates a synergistic effect where the combination of layers provides superior protection against curb contact while maintaining flexibility and reducing susceptibility to shocks compared to a uniformly thickened design.

Inventive Principle:
Principle #40Composite materials

2Duration of action of stationary object

If multiple layers of reinforcing elements are added to strengthen the bead zone, then the tire's endurance improves, but the device complexity and manufacturing difficulty increases

Engineering Contradiction:
Improvetire enduranceVSAvoidbead zone structure complexity
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the reinforcement structure into distinct functional zones: a single layer of carcass reinforcement for the bead zone (anchored at the beads) and a separate crown reinforcement consisting of at least two layers at specific angles. This segmentation allows each layer to perform its specific function optimally while simplifying the overall manufacturing process compared to using multiple layers throughout the entire tire structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses partial action by applying reinforcement selectively only where needed - the single layer of carcass reinforcement is concentrated at the bead zone where it is most needed for endurance, while the crown reinforcement extends to the tire crown. This avoids the complexity of uniformly thickening the entire tire structure while still achieving the desired endurance improvement.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If the carcass reinforcement layer is extended axially outside the upturn to cover free ends, then the protection against unwinding improves, but the tire profile fragility increases

Engineering Contradiction:
Improveprotection against unwindingVSAvoidprofile fragility during curb contact
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies the taking out principle by extracting the protective function from the carcass reinforcement layer extension and assigning it to the crown reinforcement instead. The carcass reinforcement is kept as a single layer anchored at the beads without excessive axial extension, while the crown reinforcement (at least two layers at 10° to 45° angles) provides the necessary protection against unwinding during accidental heating. This separation reduces profile fragility while maintaining reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3820721B1Tyre comprising reinforced sidewalls
Publication Date: 2022.03.23 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
  • EP3820721B1 patent drawingFigure 1
  • EP3820721B1 patent drawingFigure 2
  • EP3820721B1 patent drawingFigure 3

AI summary

The invention relates to a tyre with a radial carcass reinforcement formed by a single ply of reinforcement elements anchored in each of the beads by being turned up around a bead core (4) reinforced by a stiffening element (9). According to the invention, in the sidewall of the tyre, the profile of the outer surface (S) of the tyre is at a constant distance (D) from the carcass reinforcement ply between the points F and A, and joins the outer surface of the bead at the point C, forming two successive arcs of circles (C1 and C2).