Double-Layer Multi-Strand Cable for Bending and Corrosion Endurance

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Solution Overview

Problem

Heavy industrial vehicle tires, particularly those used in civil engineering, face premature failure due to perforations on uneven surfaces, allowing corrosive agents to oxidize metal reinforcing elements, reducing their lifespan. Existing cables have low penetrability by the elastomeric mixture, leading to poor durability in corrosive environments, and increasing breaking force or wire diameter compromises flexibility and penetrability.

Innovation Solution

A two-layer multi-strand cable design with optimized inter-wire contact surfaces and a high efficiency coefficient, combined with a polymer composition, to enhance bending endurance and corrosion resistance, while maintaining flexibility and penetrability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the cord diameter is increased beyond 0.50 mm to increase breaking strength, then the breaking force is improved, but the flexibility of the cord is reduced

Engineering Contradiction:
Improvebreaking forceVSAvoidflexibility
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The cable is divided into multiple strands, each strand containing multiple wires. This segmentation allows the overall cable to achieve high breaking strength through the cumulative effect of many individual wires, while each wire remains thin and flexible. The multi-strand construction enables the cable to maintain flexibility despite the high total strength requirement.

Inventive Principle:
Principle #1Segmentation

2Strength

If the number of cords is increased to increase breaking strength, then the breaking force is improved, but the penetrability of the strands by the elastomeric compound is reduced

Engineering Contradiction:
Improvebreaking forceVSAvoidpenetrability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies different qualities to different parts of the cable structure. The outer strands have a specific construction with controlled wire spacing and orientation that optimizes penetrability by the elastomeric compound, while the inner strands provide the primary strength. This local differentiation allows the cable to achieve both high breaking strength and good penetrability without compromising either property.

Inventive Principle:
Principle #3Local quality

3Strength

If the unit strength of each cord is increased to improve breaking strength, then the breaking force is improved, but the manufacturing investment is significantly increased

Engineering Contradiction:
Improvebreaking forceVSAvoidmanufacturing investment
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

Instead of using fewer high-strength cords that would require expensive manufacturing facilities, the patent segments the strength requirement across many standard-strength wires. This allows the use of conventional manufacturing equipment while achieving the same total breaking force, significantly reducing manufacturing investment while maintaining the required strength performance.

Inventive Principle:
Principle #1Segmentation

4Reliability

If in situ rubberization is applied to prevent corrosion by covering internal layers with rubber, then the durability in corrosive environment is improved, but the manufacturing complexity increases due to numerous industrial constraints

Engineering Contradiction:
Improvedurability in corrosive environmentVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary protection by ensuring the elastomeric compound thoroughly penetrates the strand structure during the initial cable manufacturing process. This preliminary impregnation creates a protective barrier against corrosion before the cable is put into service, eliminating the need for complex post-manufacturing rubberization processes and their associated industrial constraints.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4172407B1Double-layer multi-strand cable having improved bending endurance
Publication Date: 2024.07.31 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
  • EP4172407B1 patent drawingFigure 1
  • EP4172407B1 patent drawingFigure 2
  • EP4172407B1 patent drawingFigure 3

AI summary

The invention relates to a multi-strand cable (50) comprising an inner layer (Cl) of the cable, consisting of K=1 inner strand (Tl) that has two plies (C1, C3), the inner ply (C1) consisting of Q inner metal wires (F1) and the outer ply (C3) consisting of N outer metal wires (F3), and an outer layer (CE) of the cable, consisting of L>1 outer strands (TE) that have three plies (C1', C2', C3') and are wound around the inner layer (Cl) of the cable, the inner ply (C1') consisting of Q' inner metal wires (F1'), the intermediate ply (C2') consisting of M' intermediate metal wires (F2') and the outer ply (C3') consisting of N' outer metal wires (F3'). The cable (50) has: - an endurance criterion SL ≤ 40000 MPa.mm where SL = max (F); and - an overall dimension criterion Ec ≥ 0.46 where E = Sc/Se.