Double-Layer Multi-Strand Tire Cord for Bending Endurance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cords used in heavy-duty industrial vehicle tires, particularly those for construction plant vehicles, face issues with durability due to corrosion from uneven road surfaces, leading to reduced life expectancy, as existing solutions either compromise flexibility or require complex manufacturing processes.
Innovation Solution
A two-layer multi-strand cord design with optimized bending endurance and size criteria, featuring specific thread diameters, winding angles, and penetration coefficients, enhancing durability and resistance to corrosive environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the diameter of threads is increased to increase force at break, then the force at break increases, but the flexibility of the cord decreases
Solution Approach 1:
The cord is divided into multiple strands, each strand containing multiple threads arranged in layers. This segmentation allows the use of thinner individual threads (maintaining flexibility) while achieving high overall strength through the combined effect of many threads. The multi-strand construction with 7-19 strands provides both the required force at break and adequate flexibility for heavy-duty tire applications.
2Strength
If the number of threads is increased to increase force at break, then the force at break increases, but the ability of elastomer compound to penetrate strands decreases
Solution Approach 1:
Threads within each strand are arranged with varying characteristics - internal layers have different thread counts and diameters than external layers. This local variation in thread arrangement creates zones with different penetration resistance, allowing elastomer compound to penetrate more effectively while still maintaining high overall strength through the cumulative effect of all threads.
Solution Approach 2:
The cord structure follows a nested arrangement where multiple layers of threads are wound around each other to form strands, and multiple strands are twisted together to form the cord. This nested structure with internal, intermediate, and external layers allows elastomer penetration through the hierarchical arrangement while maintaining strength through the nested configuration of metallic elements.
3Strength
If individual thread strength is increased to increase force at break, then the force at break increases, but manufacturing investment increases significantly
Solution Approach 1:
Instead of using a few high-strength, expensive threads, the invention employs many standard-strength threads that are more economical to manufacture. The cumulative strength of numerous moderately strong threads achieves the required force at break without the significant investment needed for producing fewer ultra-high-strength threads, making the manufacturing process more cost-effective.
4Reliability
If cord structure is optimized for bending endurance, then bending endurance improves, but manufacturing complexity increases
Solution Approach 1:
The invention optimizes bending endurance by carefully selecting and adjusting parameters such as the number of strands (7-19), threads per strand (13-37), thread diameters (0.15-0.35mm), and winding angles (10-30 degrees). These parameter optimizations achieve superior bending endurance while maintaining compatibility with standard manufacturing processes, avoiding excessive complexity.
Data Source
AI summary
A multi-strand cord (50) comprises an internal layer (CI) of the cord made up of K=1 three-layer (C1, C2, C3) internal strand (TI), with the internal layer (C1) being made up of Q internal metallic threads (F1), the intermediate layer (C2) being made up of M intermediate metallic threads (F2) and the external layer (C3) being made up of N external metallic threads (F3), and an external layer (CE) of the cord made up of L>1 three-layer (C1′, C2′, C3′) external strands (TE) wound around the internal layer (CI) of the cord, with the internal layer (C1′) being made up of Q′ internal metallic threads (F1′), the intermediate layer (C2′) being made up of M′ intermediate metallic threads (F2′) and the external layer (C3′) being made up of N′ external metallic threads (F3′). The cord (50) has an endurance criterion SL≤40 000 MPa·mm withSL=max(Δσbending_CICp;Δσbending_CECr×Cp);and a size criterion Ec≥0.46 with Ec=Sc/Se.