Fuel Tank Float Valve Seal Structure for Overturn Leakage Prevention
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Solution Overview
Problem
Existing fuel tank valve devices fail to reliably close the opening portion when a vehicle is overturned, leading to potential fuel leakage due to displacement of the seal member relative to the housing.
Innovation Solution
A valve device with a housing having a partition wall with a specific opening portion design, including a first region and second regions extending in a slit shape, and a seal member with a support portion, wide portion, and narrow portion that ensures the seal member remains effective even when maximally displaced, preventing fuel from leaking into the ventilation chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional seal member is used in a valve device, then the structure is simple, but the seal member cannot reliably close the opening portion when the vehicle is overturned due to displacement
Solution Approach 1:
The seal member is divided into multiple functional regions: a first cover portion for the first region, and a second cover portion with support portion, wide portion, and narrow portion for the second region. This segmentation allows each region to perform its specific sealing function independently, ensuring reliable sealing even when displaced during vehicle overturning.
Solution Approach 2:
The seal member extends in multiple directions from the first cover portion, with the second cover portion forming a three-dimensional structure that covers the second region. This multi-dimensional configuration ensures that the seal member maintains contact with the opening portion regardless of displacement direction, improving sealing reliability under extreme conditions.
2Reliability
If the seal member is designed to cover the entire opening portion, then sealing is improved, but the displacement of the seal member relative to the opening portion causes sealing failure
Solution Approach 1:
Different regions of the seal member are designed with different properties: the support portion provides structural retention, the wide portion ensures coverage of the second region, and the narrow portion connects to the first cover portion. This local differentiation ensures that each part performs its function optimally, maintaining sealing reliability even when the overall position of the seal member changes during vehicle overturning.
3Reliability
If the opening portion is designed with a complex shape, then sealing reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The opening portion is divided into a first region and a second region, with the second region extending in a slit shape. This segmentation allows for simpler manufacturing of each region while achieving the overall complex sealing geometry required for reliable sealing under all vehicle orientations.
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 valve device reliably closes the opening portion even when the vehicle is overturned, ensuring effective sealing and preventing fuel leakage by maintaining contact between the seal member and the valve seat, even in extreme positions.
Implementation Method 1
a seal portion having elasticity for opening and closing the first opening and the second opening is disposed on an upper side of the float valve
Data Source
AI summary
There is provided a valve device, including: a housing; a float valve; and a seal member. An opening portion includes a first region, and a second region. The seal member includes a first cover portion, and a second cover portion. The second cover portion includes a support portion, a wide portion, and a narrow portion. In a state where the seal member is retained and supported by the support portion with respect to the float valve, a width of the wide portion is set such that a tip end of the second region is covered, and that the second region of the opening portion is not exposed out of the seal member even in a state where the seal member is maximally displaced in a radial direction and; or a peripheral direction of the housing with respect to the opening portion.