Wrapped Reinforcing Cord With Higher-Density Core for Bending Fatigue
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Solution Overview
Problem
Existing reinforcing cords, particularly those made of carbon fibers, suffer from crimping and bending fatigue, especially under low temperatures and repeated bending stresses, which limits their effectiveness in rubber products like belts.
Innovation Solution
A reinforcing cord design featuring a core with a higher linear density than the wrapped thread, where the thread is tightly wound around the core to prevent filament movement and deformation, enhancing resistance to crimping and bending fatigue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If carbon fibre cords are used to provide high stiffness and low weight, then tensile modulus and weight efficiency are improved, but resistance to crimping and bending fatigue deteriorates
Solution Approach 1:
The invention uses a composite structure combining carbon fibre core with polymer thread wrapping. The carbon fibre provides high tensile modulus and low weight, while the polymer thread wrapping prevents crimping and improves bending fatigue resistance. This composite approach allows both high stiffness and improved reliability to coexist.
Solution Approach 2:
The polymer thread acts as a flexible wrapping shell around the carbon fibre core. This thin film structure constrains the carbon fibre filaments, preventing them from crimping under bending stress, while maintaining the overall flexibility and light weight of the cord.
2Weight of moving object
If smaller cords are used to reduce bending strain and increase fuel efficiency, then bending strain and weight are reduced, but manufacturing precision and control of wrapping parameters become more difficult
Solution Approach 1:
The invention optimizes wrapping parameters such as thread linear density (3-10 g/km), number of wraps (500-5000 turns per meter), and wrap tension to achieve the desired balance between cord diameter, bending strain resistance, and manufacturing feasibility. These parameter adjustments allow small cord diameters while maintaining control over the wrapping process.
Data Source
AI summary
A cord for reinforcing a rubber product, comprising a core (9) and at least one thread (8) wrapped around the core, wherein the core comprises at least one strand of filaments, and wherein the linear density of the core is greater than the linear density of the thread.