Gas Generator Closing Structure for Reliable Pressure Rupture
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Solution Overview
Problem
Existing gas generators face issues with uniform cup thickness leading to fragment formation and difficulty in concentrating combustion gas at the opening area, resulting in unreliable and non-reproducible emission of combustion gas.
Innovation Solution
A gas generator design featuring a case with a funnel-shaped annular inclination portion and a lid portion of reduced thickness, integrated with a dome-shaped annular inclination portion, where the lid portion preferentially ruptures under pressure to emit combustion gas, guided by a controlled gas flow path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform thickness is used for the cup, then manufacturing is simplified, but fragment formation occurs during rupture and combustion gas concentration becomes difficult
Solution Approach 1:
The cup is designed with non-uniform thickness distribution, featuring a thin portion at the bottom end and a thick portion at the side wall. This local quality variation ensures that the thin portion ruptures preferentially to emit combustion gas while the thick portion maintains structural integrity, preventing fragment formation and ensuring reliable opening.
Solution Approach 2:
The thickness parameter of the cup is changed spatially, creating a gradient from thin at the bottom end to thick at the side wall. This parameter change optimizes both the rupture behavior for reliable gas emission and the structural strength to prevent unwanted fragmentation.
2Ease of operation
If the cup is designed to open for gas emission, then combustion gas can be emitted, but it is difficult to concentrate the combustion gas at the opening area
Solution Approach 1:
The cup's bottom end is designed with a curved, dome-like shape rather than a flat surface. This curvature naturally directs and concentrates the combustion gas toward the opening area during rupture, improving gas concentration control while maintaining the emission function.
3Reliability
If the lid portion is made with reduced thickness, then preferential rupture is achieved, but structural strength is reduced
Solution Approach 1:
The lid portion is designed with locally reduced thickness at specific areas, creating weak points that rupture preferentially under pressure. This local thinning ensures reliable opening while the overall structure maintains sufficient strength through strategically placed thicker sections.
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
Ensures highly reliable and reproducible opening of the gas generator, minimizing fragment formation and efficiently directing combustion gas emission.
Implementation Method 1
a gas generating agent that combusts by an operation of the ignition device
Implementation Method 2
a part of the cover ruptures to emit the combustion gas
Data Source
AI summary
The gas generator includes an ignition device and a case, the case including a side wall portion, an opening portion, and a closing portion closing a tip end side of the side wall portion, the opening portion being connected to the ignition device, closing portion includes, an annular inclination portion connected to the tip end side of the side wall portion, and formed in a funnel shape inclined to radially converge to an inner side of the case from a base end side toward a tip end side, and a lid portion connected to the tip end side of the annular inclination portion, the annular inclination portion and the lid portion are integrally formed, and the lid portion is formed to have a thickness smaller than a thickness of the annular inclination portion, except for an end portion of the lid portion connected to the annular inclination portion.