Wholly Aromatic Polyester Bead Fiber for Bicycle Tires
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Solution Overview
Problem
Bicycle tire bead fibers fail to achieve sufficient air volume and processability, and para-aramid fibers like Technora or Kevlar suffer from water absorption issues, requiring additional processing steps to prevent rubber deterioration.
Innovation Solution
A bead fiber composed of wholly aromatic polyester fiber with an elastic modulus of 800 cN/dtex or more, preferably in the form of a twisted or plied yarn with specific twist coefficients, is used to enhance air volume and prevent rim detachment without the need for drying before rubber application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If high-strength organic fiber is used as bead fiber to reduce weight, then weight is reduced, but air volume is insufficient
Solution Approach 1:
The patent changes the key parameter of elastic modulus from conventional values to 800 cN/dtex or more, while maintaining the fiber material as wholly aromatic polyester. This parameter change enables the bead fiber to provide both lightweight properties and sufficient air volume by enhancing the structural rigidity and air-trapping capability of the bead portion.
2Strength
If para-aramid fiber is used as bead fiber, then strength is improved, but water absorption causes rubber deterioration
Solution Approach 1:
The patent replaces para-aramid fiber with wholly aromatic polyester fiber, which has comparable or superior strength properties but does not suffer from water absorption issues. This material substitution eliminates the need for pre-drying processing and prevents rubber deterioration, effectively removing the harmful water absorption factor while maintaining high strength.
3Strength
If para-aramid fiber is used as bead fiber, then strength is improved, but additional drying processing is required
Solution Approach 1:
The patent substitutes para-aramid fiber with wholly aromatic polyester fiber that inherently resists water absorption. This material replacement eliminates the mandatory pre-drying processing step required for para-aramid fibers, simplifying the manufacturing process while maintaining the necessary strength properties for bead fibers.
4Ease of manufacture
If conventional bead fiber is used, then manufacturing is simple, but rim detachment prevention is insufficient
Solution Approach 1:
The patent elevates the elastic modulus parameter to 800 cN/dtex or more, which significantly enhances the bead fiber's ability to prevent rim detachment. This parameter change improves reliability without complicating manufacturing, as the wholly aromatic polyester fiber maintains good processability and can be manufactured using conventional methods.
Data Source
AI summary
Provided is bead fiber with which sufficient air volume can be infused for making a high-performance bicycle tire, which has superior workability that does not require drying of the bead fibers when covering the bead fibers with rubber, and which is effective in preventing rim detachment. A high-performance bicycle tire can be obtained by using this tire bead fiber. The tire bead fiber is characterized by being formed using wholly aromatic polyester fiber with a modulus of elasticity of 800 cN/dt or greater.