Two-Layer Multi-Strand Cord for Tyre Reinforcement

The cord is divided into multiple independent strands (at least three strands) with specific constructions (e.g., 7x19, 7x7). Each strand is further segmented into wire elements that can be individually optimized. This segmentation allows the cord to achieve higher energy-to-break per unit area through the combined effect of multiple strands while maintaining manageable complexity through standardized strand designs.

The cord uses composite construction combining different metal materials (e.g., steel wires, stainless steel wires, aluminum wires) with different properties in specific configurations. The core strand may use high-strength steel while outer strands use corrosion-resistant stainless steel or lightweight aluminum, creating a composite structure that optimizes both strength and durability without excessive complexity.

Different strands are assigned different local qualities based on their positions and functions. The core strand provides primary strength and deformation resistance, while outer strands use corrosion-resistant materials like stainless steel to protect against perforations and corrosive agents. This local differentiation allows the cord to simultaneously achieve breakage resistance and corrosion protection without compromising either property.

The cord structure incorporates protective measures in advance by using corrosion-resistant materials in outer strands and designing the multi-strand configuration to distribute stress before it reaches critical levels. The interlocking wire elements and strand arrangements provide cushioning against both mechanical deformation and corrosive environment exposure before damage occurs.

Instead of simply adding more threads in parallel, the invention arranges threads in three-dimensional strand structures with specific helical winding patterns. The wires are wound around core elements at controlled angles, creating a spatial configuration that distributes inter-thread contacts more evenly and reduces concentration of stress at any single contact point, thereby reducing transverse weakening while maintaining high force at break.

The invention optimizes parameters such as wire diameter, strand count, winding angle, and twist rate to achieve the desired balance. By carefully selecting these parameters, the cord achieves high force at break through optimized material distribution while minimizing transverse weakening through controlled inter-thread contact geometry. Specific embodiments use parameters like 0.25-0.50mm wire diameters and controlled helical angles to achieve this balance.