Elastomer Composite Reinforcing Elements for Tire Mass Reduction
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Solution Overview
Problem
Tire carcass reinforcements face challenges in balancing breaking strength and endurance while minimizing mass, as reducing density or increasing breaking force of reinforcing elements leads to incompatible performance characteristics, and existing solutions are industrially complex and costly for widespread tire use.
Innovation Solution
An elastomer composite with reinforcing elements comprising a multifilament strand of aromatic polyamide or aromatic copolyamide and polyester, wound helically and balanced in twists, with a specific torsion factor range and density, allowing for adaptable performance characteristics in tires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the density of reinforcing elements is reduced to lighten the carcass ply, then the mass of the tire is reduced, but the breaking force of the carcass ply decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the torsion factor within a specific range (5.2 to 6.5) and controlling residual twist to be strictly less than 2.5% of the total twist. These parameter adjustments enable the reinforcing elements to maintain high breaking force while allowing reduced density (80-145 elements per decimeter), thus resolving the contradiction between tire mass reduction and breaking force maintenance
Solution Approach 2:
The patent uses composite materials by combining aromatic polyamide or aromatic copolyamide with polyester in a multifilament strand assembly. This composite structure leverages the high strength properties of aromatic polyamide and the flexibility and endurance properties of polyester, enabling the carcass ply to achieve both reduced mass and sufficient breaking force through optimized material composition rather than relying solely on increasing element density
2Strength
If the torsion of reinforcing elements is lowered to increase breaking force, then the breaking force increases, but the endurance significantly decreases
Solution Approach 1:
The patent resolves this contradiction by establishing an optimal parameter range for the torsion factor (K = 5.2 to 6.5) and controlling residual twist to be strictly less than 2.5% of the total twist R. Within this parameter window, the reinforcing elements achieve both high breaking force and satisfactory endurance, eliminating the need to choose between the two opposing performance characteristics
Solution Approach 2:
The composite structure of aromatic polyamide and polyester filaments works synergistically to resolve the breaking force-endurance contradiction. The aromatic polyamide provides high strength for breaking force, while the polyester contributes to flexibility and durability for endurance. The helical winding and balanced twist configuration further optimize both properties simultaneously
3Reliability
If the thickness of elastomer skims is increased to ensure correct calendering and bridge formation, then the cohesion of reinforcing elements is improved, but the composite thickness and mass increase
Solution Approach 1:
The patent applies parameter changes by optimizing the density of reinforcing elements to a specific range (80-145 elements per decimeter) and controlling the torsion factor within 5.2 to 6.5. These parameter optimizations improve the spatial distribution and inter-element cohesion, allowing reduced elastomer skim thickness while maintaining reliable reinforcing element bonding and bridge formation
Data Source
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Figure 3a~3b
Figure 4~5
AI summary
The invention relates to an elastomer composite (35; 36) comprising at least one reinforcing element (44; 45) embedded in an elastomer composition, said reinforcing element (44; 45) comprising an assembly consisting of: a multifilament strand of aromatic polyamide or aromatic copolyamide, and a multifilament strand of polyester. The two strands are wound helically around one another and the reinforcing element (44; 45) has a balanced twist. The twist factor K of the reinforcing element (44; 45) varies between 5.2 and 6.5, with K being defined by the formula K = (R x Ti1/2) / 957, in which R is the twist of the reinforcing element (44; 45) expressed as turns per metre and Ti is the sum of the titres of the multifilament strands of the reinforcing element (44; 45) in tex, and the density of the reinforcing elements (44; 45) in the composite (35; 36) varies between 80 and 145 reinforcing elements per decimetre of composite.