Two-Layer Multi-Strand Cable for Tire Flexibility and Endurance
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Solution Overview
Problem
Existing cables for tire apex plies lack sufficient flexibility, structural elongation, and endurance criterion, leading to high shear stress and reduced tire lifespan under cyclic stresses.
Innovation Solution
A two-layer multi-strand cable design with helically wound inner and outer layers of metal wires, optimized for structural elongation and endurance criterion, reducing bending stress and tensile stress through specific wire diameters and mass distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a single layer of strands with high structural elongation is used, then the cable achieves sufficient flexibility and structural elongation, but the endurance criterion is insufficient leading to high shear stress in the polymer matrix
Solution Approach 1:
The cable is divided into two distinct layers: an inner layer with K strands and an outer layer with Y multi-strands, where each multi-strand contains L strands. This segmentation allows the inner layer to provide structural elongation while the outer layer enhances endurance criterion, resolving the contradiction between flexibility and reliability
Solution Approach 2:
The cable employs a composite structure combining metal wires of different diameters (d1 for internal wires, d3 for external wires) arranged in multiple layers. This composite arrangement optimizes both structural elongation and endurance criterion by distributing stresses appropriately across different material configurations
2Reliability
If thicker metal wires are used to increase endurance criterion, then the cable achieves higher breaking strength, but the cable diameter increases and flexibility is reduced
Solution Approach 1:
Instead of using fewer thick wires, the invention segments the metal content into many thinner wires arranged in multiple layers and strands. The inner layer has K strands with Q1 internal wires and Q3 external wires, while the outer layer has Y multi-strands with L strands each. This segmentation maintains small cable diameter while achieving high endurance criterion through optimized wire distribution
Solution Approach 2:
The invention changes the parameter distribution by specifying different wire diameters (d1 for internal, d3 for external) and optimizing the number of wires per strand. This parameter optimization allows the cable to achieve V1 ≥ 1000 Nxm/g endurance criterion while maintaining D ≤ 7mm diameter
3Reliability
If more metal mass is added to increase endurance criterion, then the cable achieves higher breaking strength, but the cable becomes more rigid and tire shaping is difficult
Solution Approach 1:
The metal mass is segmented into multiple thin wires arranged in helical layers rather than concentrated in few thick wires. The inner layer contains K strands and the outer layer contains Y multi-strands with L strands each, distributing the metal mass to reduce rigidity while maintaining endurance criterion through optimized wire arrangement
Solution Approach 2:
The cable employs helical winding with specific pitch values (p1 for inner layer, p3 for outer layer) that allow the structure to be dynamic and flexible. The helical arrangement enables the cable to conform to tire shapes while the optimized metal distribution maintains sufficient endurance criterion
Data Source
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AI summary
The invention relates to a multi-strand cable (50) with two multi-strand layers, the cable (50) comprising: - an inner layer (CI) of the cable, made up of X = 1 multi-strand (M1) comprising K > 1 strands (T1) helically wound around a main axis (A), each strand (T1) being a strand with least two layers (C1, C3); and - an outer layer (CE) of the cable, made up of Y > 1 multi-strands (M2) wound around the inner layer (CI) of the cable, each multi-strand (M2) comprising L > 1 strands (T2) helically wound around a main axis (A'), each strand (T2) being a strand with at least two layers (C1'; C3'), with the multi-strands (M2) being helically wound around the main axis (A). The cable (50) has an endurance criterion V1 = Δσ bending (M/D) < 3000 N x m/g. The cable (50) has a structural elongation As such that As ≥ 1.0%.