Bellows Filler Pipe Layer Structure to Suppress Fuel Swelling
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Solution Overview
Problem
The formation of bellows sections in filler pipes leads to uneven thickness distribution, particularly with the inner layer becoming thicker in peaks, causing swelling deformation when in contact with fuel.
Innovation Solution
A filler pipe manufacturing method where the inner layer is extruded thinner than the outer layer, and the forming process ensures that the increase rate of the inner layer in peaks is equal to or less than the outer layer in peaks, relative to their respective proportions in the ordinary section, using a pipe manufacturing apparatus with split forming molds to shape the tubular material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the bellows section is formed by suction in the pipe manufacturing apparatus, then the tubular material is transferred to the forming surface, but the inner layer thickness increases in the peak regions causing swelling deformation
Solution Approach 1:
The patent applies local quality by making the inner layer thickness vary in a controlled manner across different regions of the pipe. Specifically, the inner layer is designed to be thinner in the peak regions of the bellows section compared to the ordinary section, while the outer layer maintains relatively uniform thickness. This local variation in layer thickness prevents swelling deformation in fuel-contact regions while maintaining the necessary bellows structure for flexibility.
Solution Approach 2:
The patent employs parameter changes by adjusting the extrusion parameters of the tubular material to control the initial thickness distribution of the inner and outer layers. By setting the outer layer to be thicker than the inner layer in the extrusion process, and controlling the forming parameters to limit the increase rate of inner layer proportion in peaks, the patent achieves the desired thickness distribution that prevents swelling while maintaining manufacturability.
2Reliability
If the inner layer is made thicker to improve fuel resistance, then swelling deformation is suppressed, but the overall pipe weight increases
Solution Approach 1:
The patent applies local quality by concentrating the necessary material thickness only where fuel contact occurs (inner layer in ordinary sections and valley regions), while using thinner material in non-fuel contact regions (inner layer in peak regions). This localized material distribution provides adequate fuel resistance where needed while minimizing overall pipe weight by avoiding unnecessary material in regions that do not contact fuel.
3Weight of moving object
If the outer layer is made thinner to reduce weight, then material usage decreases, but the structural integrity and protection capability are reduced
Solution Approach 1:
The patent applies local quality by designing the outer layer to be uniformly thick across all sections (ordinary and bellows sections), providing consistent structural protection and integrity. This uniform outer layer thickness ensures adequate structural integrity and protection capability while allowing the inner layer to be thinner in peak regions, thereby reducing overall weight and material usage compared to designs with uniformly thick inner layers.
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 method effectively suppresses swelling deformation by maintaining a thinner inner layer in the bellows section peaks, preventing contact with fuel and subsequent deformation.
Implementation Method 1
the outer layer of the bellows section is sucked to transfer the tubular material to the split forming molds
Data Source
AI summary
A filler pipe for suppressing swelling deformation caused by fuel, and a manufacturing method thereof. A resin filler pipe has a bellows section, including peaks and valleys, and an ordinary section, not including the bellows section, and is provided with at least inner layers, barrier layers, and outer layers. In the ordinary section, the inner layer is thinner than the outer layer, and the rate of increase in the proportion of the inner layer in the peaks of the bellows section with respect to the proportion of the inner layer in the ordinary section is equal to or less than the rate of increase in the proportion of the outer layer in the peaks of the bellows section with respect to the proportion of the outer layer in the ordinary section.