Resin Pressure Vessel Liner With Tapered Wall and Anti-Buckling Rib
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Solution Overview
Problem
Existing pressure vessel liners face issues with uneven molding accuracy and stress concentration due to non-uniform wall thickness, leading to reduced strength and potential buckling, especially when the gate for resin injection is off-center, causing differences in plate thickness and surface levels.
Innovation Solution
The pressure vessel liner is designed with a second liner member having a wall thickness that gradually decreases from the midsection to both ends, joined with first liner members, and features a reinforcing rib on the inner peripheral surface, ensuring uniform holding pressure and improved molding accuracy, while preventing stress concentration and buckling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the gate is positioned axially off the center of the cavity for injection molding, then the molding process can be simplified, but the molding accuracy at both ends in the axial direction deteriorates due to uneven holding pressure
Solution Approach 1:
The cavity is designed with asymmetric wall thickness distribution, being thinner at both ends in the axial direction and thicker at the midsection. This asymmetric geometry compensates for the off-center gate positioning, ensuring that holding pressure is evenly distributed during injection molding, thereby maintaining high molding accuracy at both ends while allowing gate simplification
2Ease of manufacture
If the wall thickness of the second liner member is non-uniform, then the molding process becomes easier, but stress concentration occurs at joint sections, reducing the strength of the pressure vessel liner
Solution Approach 1:
The liner member is designed with locally optimized wall thickness distribution, where the wall thickness varies along the axial direction to ensure uniform holding pressure during molding. This local quality adjustment prevents stress concentration at joint sections while maintaining ease of manufacture, thereby preserving the strength of the pressure vessel liner
3Volume of stationary object
If a second liner member in a bottomless cylindrical shape is interposed between the pair of first liner members to increase the pressure vessel size, then the pressure vessel capacity increases, but the risk of buckling increases when internal pressure is smaller than external pressure
Solution Approach 1:
The liner member is designed with a curved, cylindrical geometry that provides structural stability. The curved shape distributes external pressure more evenly, reducing the risk of buckling when internal pressure is smaller than external pressure, while still allowing the pressure vessel capacity to be increased by interposing the second liner member
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 design enhances the strength and durability of the pressure vessel liner by ensuring uniform wall thickness and incorporating a reinforcing rib, thereby reducing stress concentration and preventing buckling, while also simplifying the manufacturing process.
Implementation Method 1
a resin injected such that a wall thickness of a molded product gradually decreases from a center in the axial direction of a cavity in a molding die toward both ends in the axial direction of the cavity
Data Source
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AI summary
A pressure vessel liner (1) is made of resin and has a pair of first liner members (10), in a bottomed cylindrical shape, joined with a second liner member (20) in a bottomless cylindrical shape, wherein the second liner member (20) has a wall thickness thereof gradually decreasing from a midsection in an axial direction thereof toward joint sections (A) at both ends in the axial direction. In addition, the second liner member (20) is formed with a reinforcing rib (21) at the midsection, circumferentially on an inner peripheral surface thereof.