Pneumatic Tire Bead Core Weight Reduction Using Carbon Glass Composite Cord
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Solution Overview
Problem
Pneumatic tires face challenges in weight reduction of bead cores while maintaining performance, as non-metallic materials like carbon fibers tend to buckle and suffer from stress concentration, leading to reduced strength and practicality.
Innovation Solution
A composite cord comprising carbon fibers and glass fibers is used, with a multilayer or cable bead structure, where the glass fibers improve fatigue resistance and the carbon fibers provide high strength, ensuring the bead core's burst pressure remains consistent even with increased windings, and the composite cord is spirally wound around an annular core body to distribute stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If non-metallic materials like carbon fibers are used for bead cores, then weight reduction is achieved, but the bead cores may buckle locally and suffer from stress concentration leading to reduced strength
Solution Approach 1:
The patent applies composite materials by combining carbon fibers (for high strength) with glass fibers (for fatigue resistance and buckling prevention) in a single cord structure. This composite construction allows the bead core to achieve both weight reduction and sufficient mechanical strength, resolving the contradiction between using lightweight non-metallic materials and maintaining required strength properties.
Solution Approach 2:
The patent applies local quality by creating a multilayer cord structure where different fiber types are positioned at specific locations. The glass fibers are arranged to prevent buckling in critical areas while carbon fibers provide strength where needed. This localized functional distribution allows the bead core to simultaneously achieve weight reduction and maintain strength through strategic material placement.
2Weight of moving object
If carbon fiber cords are used for bead cores, then weight reduction is achieved, but fatigue resistance is poor leading to reduced reliability
Solution Approach 1:
The patent combines carbon fibers (providing high strength and weight reduction) with glass fibers (providing excellent fatigue resistance). This composite material approach allows the bead core to achieve both weight reduction and improved reliability, as the glass fiber component specifically addresses the poor fatigue resistance of pure carbon fiber cords.
Solution Approach 2:
The patent changes the material composition parameters by introducing glass fibers into the carbon fiber structure. This parameter modification (adding a second material phase) transforms the bead core from having poor fatigue resistance to having improved reliability, while maintaining the weight reduction benefits of the carbon fiber base material.
3Strength
If multilayer bead structure with increased windings is used, then burst pressure increases, but manufacturing complexity increases
Solution Approach 1:
The patent uses a composite cord structure that inherently provides both strength and structural integrity in a unified construction. This composite approach achieves the required burst pressure without requiring excessive multilayer windings, as the composite material properties themselves contribute to pressure resistance, thereby reducing manufacturing complexity.
Solution Approach 2:
The patent applies local quality by strategically positioning different fiber types within the cord structure to optimize performance. This localized functional distribution achieves the necessary burst pressure through efficient material placement rather than through increased complexity of multilayer windings, simplifying the manufacturing process.
Data Source
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AI summary
A pneumatic tire is provided that can achieve performance that is equivalent to or higher than that of known tires while allowing weight reduction of bead cores by using, for the bead cores, a composite cord. A pneumatic tire includes annular bead cores (5) embedded in bead portions (3), and a carcass layer (4) locked on the bead cores (5). Each of the bead cores (5) includes a cable bead structure in which a composite cord (10) is spirally wound around an annular core body (20), the composite cord including a core wire (11) formed of carbon fibers and a plurality of siding wires (12) formed of glass fibers disposed around the core wire (11).