Filament Winding Terminal End Fixation for Hydrogen Tanks

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The filament winding method for manufacturing high-pressure hydrogen tanks faces issues with terminal end fixation, leading to surface irregularities and reduced operability, particularly in mass production, due to manual operations and the use of double-faced tape or insertion methods that cause bulging and stress concentration.

Innovation Solution

A method where the terminal end of the fiber is tucked into the inner fiber layer, allowing the fixing region to be inserted between adjacent fibers, alleviating local bulging and improving surface smoothness and operability by using a terminal end handling jig to widen the space and secure the fixing region within the inner layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the terminal end of the fiber is tied and fixed by an operator's hand, then the fiber end is securely attached, but the winding step takes a lot of time and effort

Engineering Contradiction:
Improveattachment strength of fiber terminal endVSAvoidwinding speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The fiber terminal end automatically attaches itself to the winding surface through self-adhesion without requiring manual intervention. The fiber's own properties (adhesiveness) are utilized to secure its end, eliminating the need for operator tying operations while maintaining reliable attachment.

Inventive Principle:
Principle #25Self-service

2Ease of manufacture

If double-faced tape is used to fix the terminal end of the fiber, then the attachment is simplified, but irregularities are formed on the outer surface of the tank

Engineering Contradiction:
Improveease of terminal end fixationVSAvoidsurface smoothness
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The double-faced tape is completely removed from the process. Instead of using an external fixing material that causes surface irregularities, the invention relies on the fiber's inherent self-adhesive properties to attach the terminal end directly to the winding surface, eliminating the source of surface defects.

Inventive Principle:
Principle #2Taking out (Extraction)

3Extent of automation

If the terminal end of the fiber is inserted into the already-wound fiber, then manual fixation is avoided, but irregularities and stress concentration occur on the surface

Engineering Contradiction:
Improveautomation of terminal end fixationVSAvoidsurface smoothness
Core Design Contradiction:
Extent of automationVSManufacturing precision

Solution Approach 1:

The fiber terminal end uses its own adhesiveness to attach to the winding surface without being inserted into or held by the already-wound fiber structure. This self-adhesive mechanism provides automation while avoiding the creation of surface irregularities and stress concentration points that result from insertion methods.

Inventive Principle:
Principle #25Self-service

4Ease of manufacture

If the viscosity of resin is lowered for easy impregnation, then fiber impregnation is improved, but the terminal end becomes easily loosened during thermal curing

Engineering Contradiction:
Improvefiber impregnation easeVSAvoidterminal end attachment strength
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The fiber terminal end utilizes its inherent self-adhesive property to maintain attachment during thermal curing, independent of resin viscosity changes. This self-service mechanism ensures the terminal end remains securely attached even when low-viscosity resin is used for easy impregnation, as the attachment relies on fiber properties rather than resin state.

Inventive Principle:
Principle #25Self-service

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

This approach enhances the smoothness of the tank's surface, improves manufacturing operability, and securely fixes the terminal end, reducing the likelihood of bulging and stress concentration, thus enhancing the strength and appearance of the finished product.

Implementation Method 1

a curing step of thermally curing the impregnating resin in the wound fiber to thereby form the reinforcement fiber layer

Methodology Applied
Scientific EffectThermal curing: Phase Change

Data Source

PatentEP2799214B1Manufacturing method for a tank
Publication Date: 2017.12.13 TOYOTA JIDOSHA KK
  • EP2799214B1 patent drawingFigure 1
  • EP2799214B1 patent drawingFigure 2
  • EP2799214B1 patent drawingFigure 3(A)~3(B)

AI summary

The present invention provides a method of manufacturing a tank having a reinforcement fiber layer, the method comprising: a winding step of winding a fiber impregnated with resin by a predetermined number of windings; and a curing step of thermally curing the impregnating resin in the wound fiber to thereby form the reinforcement fiber layer. In the winding step, an end portion, being a winding end, of the fiber is tucked into an inner fiber layer which has already been wound to thereby insert at least a portion of a fixing region that is a part of the end portion into between fibers forming the outermost layer so that the end portion is fixed to the inner fiber layer.