Valve Device Tilted Lead-in Passage for Stress Reduction
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Solution Overview
Problem
Valve devices for high-pressure gas tanks, such as those used in fuel cell vehicles, face challenges in reducing weight while maintaining durability due to stress concentration at sharp angles in the valve insertion holes, which can lead to durability issues when using lightweight materials like aluminum alloys.
Innovation Solution
The valve device features a lead-in passage that is tilted with respect to the normal line of the valve insertion hole's inner surface, reducing stress concentration by altering the angle from sharp to obtuse, and can extend in a plane perpendicular to the center axis with an offset, improving durability and ease of working.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the lead-in passage opening is formed in the smooth inner surface of the valve insertion hole, then the manufacturing is simple, but stress concentration occurs at the sharp angle corner
Solution Approach 1:
The lead-in passage is positioned asymmetrically with respect to the valve insertion hole, such that the passage is tilted relative to the normal line of the hole's inner surface. This asymmetric arrangement creates an obtuse angle at the opening corner, eliminating stress concentration while maintaining manufacturing simplicity through a single-formed structure without requiring post-processing
2Weight of moving object
If aluminum alloy is used for the body, then weight is reduced, but durability decreases due to stress concentration
Solution Approach 1:
The asymmetric positioning of the lead-in passage creates an obtuse angle configuration that eliminates stress concentration points. This allows the use of lightweight aluminum alloy materials without compromising durability, as the asymmetric geometry prevents the stress concentration that would otherwise lead to fatigue failure in lightweight materials
3Strength
If the lead-in passage is tilted with respect to the normal line, then stress concentration is alleviated, but the manufacturing precision requirement increases
Solution Approach 1:
The asymmetric tilt angle is built into the basic geometric configuration of the lead-in passage during the primary manufacturing process. This preliminary design of the tilted passage ensures that the obtuse angle configuration is achieved without requiring high-precision post-processing or complex manufacturing steps, thereby maintaining ease of manufacture while eliminating stress concentration
Data Source
AI summary
A valve device includes: a valve member that controls flow of a fluid, and a body that has a valve insertion hole in which the valve member is inserted, and whose inner surface is cylindrically formed, and into which the fluid flows, and a lead-in passage that has an opening in the inner surface of the valve insertion hole, and that causes the fluid to flow into the valve insertion hole. A line representing the direction of extension of the lead-in passage is tilted from a line normal to the inner surface of the valve insertion hole at a position of the opening of the lead-in passage, in a view in the axis direction of the valve insertion hole.