Valve Joint Sealing Structure to Protect Threaded Regions
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Solution Overview
Problem
In valve devices for gas tanks in fuel cell-powered vehicles, high-pressure hydrogen gas accumulates in the threaded regions due to gaps between the sealing member and the valve seat fixation member, causing repeated stress and potential fatigue, which compromises the device's strength and air tightness.
Innovation Solution
A sealing structure is implemented where the sealing member is compressed between the joint and the valve seat fixation member, positioned radially inward of the threaded regions, blocking gas from reaching the screws and reducing stress on the threaded areas, and a tapered surface on the joint tip prevents separation-induced stress by hooking into the attachment hole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing member is positioned between the joint and valve seat fixation member, then air tightness is maintained, but gas accumulates in the screwed region causing stress and fatigue
Solution Approach 1:
The sealing member is repositioned from a radial sealing location to an axial sealing location, specifically between the joint and valve seat fixation member. This dimensional change in sealing position blocks the gas flow path before it reaches the screwed region, eliminating gas accumulation while maintaining air tightness. The sealing member now seals in the axial direction rather than radially, preventing gas from entering the screwed region between the internal and external threads.
2Strength
If the sealing member is moved radially inward to block gas, then gas accumulation is prevented, but the sealing effectiveness may be compromised
Solution Approach 1:
The sealing member acts as an intermediary element positioned between the joint and valve seat fixation member. It mediates the conflict between gas flow blocking and sealing requirements by creating a sealed chamber that contains gas pressure while preventing gas from reaching the screwed region. The sealing member transfers the sealing function from the radial interface to the axial interface, maintaining effectiveness while protecting the threaded regions.
3Strength
If the joint tip is designed with a tapered surface, then separation-induced stress is reduced, but manufacturing complexity increases
Solution Approach 1:
The joint tip is designed with a tapered surface instead of a flat or sharp edge. This curved/geometric modification allows the joint to gradually engage with the attachment hole during assembly, preventing sudden impact loads and separation-induced stress. The tapered geometry distributes mechanical stress over a larger area and longer engagement distance, enhancing durability while remaining compatible with standard manufacturing processes.
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 configuration effectively prevents gas from entering the threaded regions, reducing stress on the screws, maintaining air tightness, and enhancing the device's durability by minimizing the impact of high-pressure hydrogen gas and potential impacts.
Implementation Method 1
The sealing member that maintains air tightness between the joint and the valve seat fixation member is provided in a compressed state between the joint and the valve seat fixation member
Implementation Method 2
An outer peripheral edge of the sealing member is located radially inward of a screwed region of the internal thread and the external thread... the supplied gas is blocked by the sealing member that is compressed between the joint and the valve seat fixation member, before reaching the screwed region
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A valve device (1) includes a body (4), a joint (6), a check valve (16), a valve seat fixation member (30) having an outer peripheral surface on which an external thread (30a) is provided, and a sealing member (70). The body (4) has an attachment hole (21) that attaches the joint (6) and the valve seat fixation member (30) from an outside of the body (4) in a sequence of the joint (6) and the valve seat fixation member (30), and that has an inner peripheral surface in which an internal thread (23a) screwed to the external thread (30a) of the valve seat fixation member (30) is provided. The sealing member (70) is provided between the joint (6) and the valve seat fixation member (30). An outer peripheral edge of the sealing member (70) is located radially inward of a screwed region of the internal thread (23a) and the external thread (30a).