Wrapped Reinforcing Cord Structure for Crimp and Bending Fatigue

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Solution Overview

Problem

Carbon fibre reinforcing cords in rubber products suffer from low resistance to crimping and bending fatigue, especially under bending stresses and at low temperatures, which limits their durability and efficiency in applications like rubber belts.

Innovation Solution

A cord design featuring a core with a higher linear density than the wrapped thread, where the thread restricts filament movement and deformation, enhancing stiffness and resistance to crimping, using materials like carbon, glass, or basalt filaments with a lightweight and non-bulky thread.

Engineering Contradictions & Design Principles

VSEngineering 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

Engineering Contradiction:
Improvetensile modulusVSAvoidresistance to crimping and bending fatigue
Core Design Contradiction:
StrengthVSReliability

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.

Inventive Principle:
Principle #40Composite materials

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.

Inventive Principle:
Principle #30Flexible shells and thin films

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

Engineering Contradiction:
Improvecord weightVSAvoidwrapping parameter control
Core Design Contradiction:
Weight of moving objectVSManufacturing precision

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.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20230043287A1Wrapped cord for reinforcing a rubber product
Publication Date: 2023.02.09 NGF EURO
  • US20230043287A1 patent drawing
  • US20230043287A1 patent drawing
  • US20230043287A1 patent drawing

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.