Automotive Fuel Filler Neck Resin-Metal Retainer Design
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Solution Overview
Problem
The existing filler neck designs using resin pipes for automobiles face issues with sealing properties due to swelling of the resin when exposed to fuel, leading to peeling of the metal retainer and increased man-hours for selecting molding conditions and resin materials.
Innovation Solution
A filler neck design featuring a resin inner layer with a polyamide material for fuel permeability resistance and a polyethylene outer layer with a maleic acid functional group, combined with a metal retainer and outer circumference protector, which suppresses deformation and maintains sealing properties by covering the resin layers and providing mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the metal retainer is mounted directly on the resin pipe main body, then assembly is simplified, but the retainer peels off when the resin swells due to fuel exposure
Solution Approach 1:
The outer layer made of resin B acts as an intermediary between the inner resin layer and the metal retainer. This intermediate layer provides good adhesivity to both the inner resin and the metal retainer, ensuring strong bonding while accommodating the swelling of the inner layer due to fuel exposure. The intermediary layer prevents direct stress transmission that would cause peeling, thus maintaining retainer bonding reliability.
2Reliability
If resin material with high fuel permeability resistance is selected, then fuel permeability resistance is improved, but swelling occurs leading to increased man hours for selection of molding conditions and resin material
Solution Approach 1:
The invention changes the material composition parameter by using a two-layer resin structure instead of a single resin material. The inner layer uses resin A optimized for fuel permeability resistance, while the outer layer uses resin B optimized for adhesivity and dimensional stability. This parameter change (from single material to composite material) allows the system to achieve high fuel resistance without the swelling problems that would require extensive trial and error in material selection.
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 design effectively prevents resin swelling and maintains sealing integrity by using a polyethylene outer layer with reactive adhesion to polyamide, enhancing fuel resistance and mechanical strength, while the metal retainer ensures durable sealing and resistance to external forces.
Implementation Method 1
a polyethylene outer layer with a maleic acid functional group, combined with a metal retainer and outer circumference protector, which suppresses deformation and maintains sealing properties by covering the resin layers and providing mechanical strength
Implementation Method 2
an outer circumference protector part that is bent to an outer circumference side from the seal part and covers an outside surface of the resin outer layer
Data Source
AI summary
A filler neck is equipped with a neck main body having a pipe shaped resin inner layer and resin outer layer, and a retainer made of metal mounted so as to cover the edge part of the neck main body. The resin inner layer and the resin outer layer are made of resin materials for which one layer has superior fuel permeability resistance to the other layer. The resin inner layer has a screw part for screwing into a screw part of a fuel cap on the inner wall of the resin inner layer. The retainer has a seal part for sealing between the gasket, and a round cylinder shaped outer circumference protector part. The lower end of the outer circumference protector part is on plane perpendicular to the center axis of the fuel path. The plane includes the screw part.