Polyamide Cord Endless Flat Belt for Stable Twist Travel

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Solution Overview

Problem

Existing endless flat belts used for twist travel, such as paper tube winding, face issues with breakage due to stress concentration at joints, uneven winding pressure, and one-sided elongation, leading to instability and short service life, especially when manufactured without cylindrical metal molds for varying lengths.

Innovation Solution

An endless flat belt design featuring a polyamide fiber cord core buried in an inner rubber layer, with specific modulus of elasticity values for the cord core and reinforcement fabric, allowing for stable tension and performance during twist travel, and a method to manufacture belts of various lengths without cylindrical metal molds by connecting reinforcement fabric ends and applying vulcanization molding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If adhesive is used to join belt ends, then the belt can be made endless, but the joint part hardens and stress concentration occurs leading to breakage

Engineering Contradiction:
Improvebelt service lifeVSAvoidjoint part strength
Core Design Contradiction:
Duration of action of moving objectVSStrength

Solution Approach 1:

The patent removes the adhesive joint from the belt structure entirely by using a continuous loop design where the belt ends are joined through the molding process itself rather than post-assembly adhesive bonding. This eliminates the hardened joint portion that causes stress concentration and breakage.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The belt is molded as a continuous loop from the beginning, with the end portions connected through the molding process itself rather than requiring post-manufacturing assembly. This preliminary formation of the endless structure prevents the creation of weak joint sections.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If belt tension is increased to eliminate uneven winding pressure, then winding performance improves, but belt wear increases and service life decreases

Engineering Contradiction:
Improvewinding performanceVSAvoidbelt service life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent creates different structural zones within the belt: the inner rubber layer with cord core provides high tensile strength for tension resistance, while the reinforcement fabric layers provide surface durability for wear resistance. This local differentiation allows the belt to handle high tension without increasing overall wear.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The belt uses a composite structure combining rubber material with reinforcement fabric and cord core. This composite design provides both the tensile strength needed for high tension operation and the surface durability required for extended service life, resolving the contradiction between winding performance and service life.

Inventive Principle:
Principle #40Composite materials

3Reliability

If strong winding is applied to eliminate uneven pressure, then winding performance improves, but power consumption increases and mandrel wear increases

Engineering Contradiction:
Improvewinding performanceVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the physical parameters of the belt by optimizing the modulus of elasticity of the cord core (10-200 MPa) and reinforcement fabric to achieve the right balance between flexibility for easy winding and strength for maintaining tension. This allows effective winding performance with reduced power consumption.

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If belt is softened to improve winding performance, then flexibility improves, but deformation volume increases leading to uneven wear

Engineering Contradiction:
Improvewinding flexibilityVSAvoidbelt deformation
Core Design Contradiction:
Ease of operationVSShape

Solution Approach 1:

The belt structure differentiates between the inner rubber layer containing the cord core, which provides flexibility and elastic recovery to prevent permanent deformation, and the outer reinforcement fabric layers that maintain shape stability. This local functional differentiation resolves the contradiction between flexibility and shape retention.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution stabilizes belt tension and performance, prevents breakage and one-sided elongation, ensures longer service life, and allows for easy production of belts with large circumferential lengths, while maintaining rigidity and equalizing winding pressure.

Implementation Method 1

a cord core which is wound spirally at a predetermined pitch in a width direction of the endless flat belt

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a reinforcement fabric stuck to one surface of the inner rubber layer

Methodology Applied
Scientific EffectTensile strength: Elasticity

Implementation Method 3

applying vulcanization molding

Methodology Applied
Scientific EffectVulcanization: Chemical Bonding

Data Source

PatentEP3144559B1Endless flat belt and method for manufacturing same
Publication Date: 2022.04.27 NITTA CORP
  • EP3144559B1 patent drawingFigure 1~4
  • EP3144559B1 patent drawingFigure 5(a)~6
  • EP3144559B1 patent drawingFigure 7(a)~8

AI summary

An endless flat belt includes an inner rubber layer 1, a cord core 11 buried in the inner rubber layer 1 and spirally wound at a predetermined pitch in a width direction of the belt, and a reinforcement fabric 2 stuck to the inner rubber layer 1. The cord core comprises polyamide fiber. Opposite ends of the reinforcement fabric 2 are connected with each other into an endless form by adhesion or sewing. A surface rubber layer 3 is stuck to a surface of the reinforcement fabric 2 which is opposite a surface thereof stuck to the inner rubber layer 1.