Multilayer Tip Rod Fiber Orientation for Flexibility and Strength

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Solution Overview

Problem

Conventional solid tip rods made of continuous fiber-reinforced resin materials lack flexibility and strength, particularly against shear and torsional forces, making them prone to breakage and difficult to assemble, while reducing the outer diameter for increased flexibility complicates processing and assembly.

Innovation Solution

A tip rod with a solid structure at its distal end, formed by dispersing reinforcement fibers in a matrix resin, featuring a three-layered design where fibers in each layer are directed differently, enhancing flexibility and strength against shear and torsional forces, allowing for easier assembly and processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If continuous fiber-reinforced resin material is used to make the tip rod solid, then strength and rigidity are improved, but flexibility and resistance to shear/torsional forces deteriorate

Engineering Contradiction:
Improvestrength against bendingVSAvoidflexibility
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The tip rod is segmented into multiple layers (outer layer, intermediate layer, inner layer) with different fiber orientations. Each layer contributes differently to mechanical properties: outer and inner layers provide bending strength with axial fibers, while intermediate layers provide shear resistance with circumferential fibers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the tip rod have different fiber orientations tailored to local stress requirements. The outer and inner layers have axial fibers for bending resistance, while intermediate layers have circumferential fibers for shear resistance, creating localized property optimization.

Inventive Principle:
Principle #3Local quality

2Strength

If continuous fiber-reinforced resin material is used to make the tip rod solid, then rigidity is improved, but resistance to torsional forces deteriorates

Engineering Contradiction:
Improverigidity against bendingVSAvoidresistance to torsional force
Core Design Contradiction:
StrengthVSForce

Solution Approach 1:

The tip rod structure is segmented into layers with different fiber orientations. Intermediate layers with circumferential fibers specifically address torsional resistance, while outer and inner layers maintain bending rigidity with axial fibers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Circumferential fibers are placed in intermediate layers specifically to resist torsional forces where they are most effective, while axial fibers in outer and inner layers maintain bending rigidity, creating localized property optimization for different force types.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the outer diameter of the tip rod is reduced to increase flexibility, then flexibility is improved, but processing difficulty and assembly difficulty increase

Engineering Contradiction:
ImproveflexibilityVSAvoidprocessing difficulty
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The invention changes the structural parameters by introducing a multilayer configuration with different fiber orientations and ratios. This allows the tip rod to maintain a practical outer diameter while achieving flexibility through the compliant intermediate layers with circumferential fibers.

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If the outer diameter of the tip rod is reduced to increase flexibility, then flexibility is improved, but strength against shear stress deteriorates

Engineering Contradiction:
ImproveflexibilityVSAvoidstrength against shear stress
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The tip rod is segmented into layers where intermediate layers with circumferential fibers specifically resist shear stresses. These layers act as shear webs that prevent breakage while allowing the overall rod to remain flexible.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Circumferential fibers are placed in intermediate layers specifically to resist shear stresses that occur during bending and torsion, while axial fibers in outer and inner layers maintain flexibility and bending strength.

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 tip rod achieves increased flexibility and resistance to breakage, enabling better sensitivity to fish bites and enhanced strength against shear rigidity, while allowing for easier assembly and processing, even with a larger outer diameter.

Implementation Method 1

molding the matrix resin that contains the reinforcement fibers into a prescribed shape, and heating the molded matrix resin that contains the reinforcement fibers to be cured

Methodology Applied
Scientific EffectCuring: Photopolymerisation

Data Source

PatentEP3036992B1Tip rod and fishing rod having the same
Publication Date: 2019.07.24 DAIWA SEIKO CORPORATION
  • EP3036992B1 patent drawingFigure 1
  • EP3036992B1 patent drawingFigure 2
  • EP3036992B1 patent drawingFigure 3

AI summary

A flexible and durable tip rod (12) and a fishing rod (1) having the same is provided. A tip rod (12) according to the disclosure is made of a fiber reinforced resin. The tip rod (12) has a solid structure at least at its distal end portion. The tip rod (12) is formed by dispersing reinforcement fibers (22, 22a, 22b) in a matrix resin (20), molding the matrix resin (20) that contains the reinforcement fibers (22, 22a, 22b) into a prescribed shape, and heating the molded matrix resin (20) that contains the reinforcement fibers (22, 22a, 22b) to be cured. An average diameter of the reinforcement fibers (22, 22a, 22b) is 3 to 15 µm, an average length of the reinforcement fibers (22, 22a, 22b) is 0.5 to 10 mm, a content of the fibers (22, 22a, 22b) dispersed in the matrix resin (20) is to 3 to 50 wt%. The solid structure of the tip rod (12) includes three layers, which are an outer layer (A), an intermediate layer (B), and an inner layer (C) in which the reinforcement fibers (22, 22a, 22b) are directed in a different direction for each layer. Alternatively the solid structure may include two layers, which are the outer layer (A) and the inner layer (B).