Pneumatic Tire Reinforcing Cord Buckling Prevention

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Solution Overview

Problem

Pneumatic tires with reinforcing cords embedded in a large inclination angle (≥40°) experience buckling and breakage due to compressive forces from road contact and high-speed travel, leading to reduced durability and handling stability.

Innovation Solution

A pneumatic tire design with reinforcing cords inclined between 40° to 90°, featuring a compressive rigidity of 1000 to 2400 N per 50 mm width and 40 to 80 cords per 50 mm, which effectively withstands compressive forces and suppresses buckling and breakage, while maintaining durability and ground contact ability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the inclination angle of reinforcing cords is increased to ≥40°, then the tire can maintain structural integrity during deformation, but compressive force is repeatedly applied to the reinforcing cords causing buckling and cord breakage

Engineering Contradiction:
Improvestructural integrityVSAvoidcord breakage resistance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent optimizes the inclination angle parameter of reinforcing cords to a specific range (40°≤α<55°) to balance structural integrity and compressive force resistance. This parameter optimization prevents excessive compressive forces while maintaining the necessary structural stability during tire deformation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent combines steel cords with specific rubber compound materials in the reinforcing layer, creating a composite structure that distributes and reduces compressive forces on the steel cords. The rubber matrix absorbs part of the compressive load, preventing direct transmission to the cords and reducing buckling risk.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the number of reinforcing cords is increased to suppress buckling, then cord breakage resistance improves, but the complexity of the reinforcing layer increases

Engineering Contradiction:
Improvecord breakage resistanceVSAvoidreinforcing layer complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent optimizes the density parameter of reinforcing cords (number of cords per unit width) to achieve the minimum required for buckling suppression without excessive complexity. By carefully selecting this parameter, the patent achieves adequate reliability while maintaining manufacturability and structural simplicity.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the compressive rigidity of the reinforcing layer is increased to prevent buckling, then cord breakage resistance improves, but durability and ground contacting ability deteriorate

Engineering Contradiction:
Improvecord breakage resistanceVSAvoiddurability
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent optimizes the compressive rigidity parameter of the reinforcing layer to a specific range that provides sufficient buckling resistance while maintaining flexibility for durability and ground contact. This balanced parameter selection prevents both buckling and excessive rigidity-related deterioration.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials in the reinforcing layer that provide adequate compressive rigidity through material properties rather than excessive cord density or stiffness. This allows the layer to resist buckling while maintaining the flexibility needed for durability and proper ground contact characteristics.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3299180B1Pneumatic tire
Publication Date: 2019.06.12 BRIDGESTONE CORP
  • EP3299180B1 patent drawingFigure 1
  • EP3299180B1 patent drawingFigure 2
  • EP3299180B1 patent drawing

AI summary

At a pneumatic tire (11), in a pneumatic tire in which a reinforcing layer (11) is structured from at least one reinforcing ply (53) in which are embedded plural reinforcing cords (54) that are formed from steel and are inclined with respect to a tire equator S, an inclination angle A of the reinforcing cords (54) with respect to the tire equator S is within a range of 40 to 90°, and a compressive rigidity F per 50 mm width of a reinforcing layer (52) in a direction parallel to the reinforcing cords (54) is within a range of 1000 to 2400 N.