Pressure Vessel Liner Wall Profile for Accurate Molding
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Solution Overview
Problem
The existing pressure vessel liners face issues with degraded molding accuracy and uneven plate thickness at both ends due to off-center injection gates, leading to stress concentration and reduced strength when joined with first liner members.
Innovation Solution
A pressure vessel liner design featuring a second liner member with joint sections at both ends and a gradually decreasing wall thickness from the midsection towards the joint sections, ensuring uniform holding pressure during injection molding and improved molding accuracy. Additionally, a reinforcing rib is formed on the inner surface of the second liner member to prevent buckling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the gate is positioned axially off the center of the cavity, then the second liner member can be molded, but the molding accuracy is degraded at both ends due to uneven holding pressure
Solution Approach 1:
The gate is intentionally positioned off-center in the cavity, creating an asymmetric injection path. This asymmetric design allows the resin to flow and distribute holding pressure in a manner that accommodates the specific geometric constraints of the second liner member, enabling successful molding while maintaining acceptable accuracy through compensated pressure distribution.
Solution Approach 2:
The invention changes the gate position parameter from center to off-center, and adjusts the cavity geometry parameters (distance between walls) to create a flow path that compensates for the off-center injection. This parameter optimization allows the resin to reach both ends of the liner member with sufficient holding pressure despite the asymmetric gate location.
2Ease of manufacture
If the plate thickness of the second liner member is non-uniform at both ends, then the liner can be molded with the off-center gate, but stress concentrates at joint sections reducing the strength of the pressure vessel liner
Solution Approach 1:
The cavity distance between walls is optimized to create a resin flow pattern that compensates for the off-center gate, ensuring more uniform plate thickness at the joint sections. This parameter adjustment reduces stress concentration and improves the overall strength of the pressure vessel liner while maintaining the benefits of off-center gate positioning.
3Volume of stationary object
If a second liner member is interposed between a pair of first liner members to increase pressure vessel size, then the pressure vessel capacity increases, but the liner becomes susceptible to buckling when internal pressure is smaller than external pressure
Solution Approach 1:
The second liner member is designed with a curved, cylindrical geometry rather than a flat structure. This curvature provides inherent buckling resistance by distributing external compressive forces uniformly across the surface, preventing localized instability while maintaining the volume expansion needed for increased pressure vessel capacity.
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 solution enhances the strength of the pressure vessel liner by eliminating stress concentration at the joint sections and preventing buckling, while also improving molding accuracy and ease of product release.
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
AI summary
A fuel tank including a built-in component is provided. The built-in component includes: a carrier part being a rigid body including a plurality of engaging parts, and a plurality of struts each including an engageable part to be engaged with one of the engaging parts. The engageable part of the strut includes an upper contact surface and a lower contact surface, which are formed spaced apart from each other in a height direction. The engaging parts of the carrier part each includes a biasing part that, when the strut is engaged with the engaging part, enters a space between the upper contact surface and the lower contact surface and generates biasing forces in directions to move the upper contact surface and the lower contact surface away from each other.