Gas Generator Seal Structure for Staged Discharge Port Rupture
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Solution Overview
Problem
In gas generators with both large-diameter and small-diameter discharge ports covered by the same seal tape, the seal tape covering the large-diameter port tends to rupture earlier, leading to unintended discharge through the small-diameter port, which can result in output characteristics not meeting design specifications.
Innovation Solution
The gas generator incorporates a closing member with distinct rupture pressures for the seal tape covering the first and second discharge ports, along with a breakage assisting portion to manage the stress distribution, ensuring that the seal tape ruptures appropriately to maintain desired output characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the same seal tape covers both large-diameter and small-diameter discharge ports, then the structure is simplified and manufacturing is easier, but the seal tape covering the large-diameter port ruptures earlier causing unintended discharge through the small-diameter port
Solution Approach 1:
The closing member is divided into multiple portions with different rupture pressures: a first portion covering the large-diameter discharge port that ruptures at a first rupture pressure, and a second portion covering the small-diameter discharge port that ruptures at a second rupture pressure higher than the first rupture pressure. This segmentation allows each portion to rupture at its designated pressure without affecting the other, resolving the reliability issue while maintaining the simplified single-piece structure.
Solution Approach 2:
Different portions of the closing member are given different local qualities in terms of rupture pressure characteristics. The first portion is designed with lower rupture pressure for the large-diameter port, while the second portion has higher rupture pressure for the small-diameter port. This local differentiation ensures that when pressure is applied, only the intended portion ruptures at each pressure level, preventing unintended discharge.
2Productivity
If the seal tape covering the large-diameter discharge port ruptures earlier, then the large-diameter port opens as intended, but the force transmits to the periphery causing the seal tape to displace or lift, releasing the small-diameter hole at lower than original rupture pressure
Solution Approach 1:
A breakage assisting portion is provided in the closing member at the boundary between the first and second portions. This breakage assisting portion is designed to rupture first when pressure is applied, serving as a preliminary action that releases stress before it can transmit to the periphery and cause displacement or lifting of the seal tape. This prevents the second portion from rupturing at lower than intended pressure.
Solution Approach 2:
The breakage assisting portion acts as an intermediary element between the first and second portions of the closing member. When the first portion ruptures, the breakage assisting portion provides a controlled stress release path, preventing the transmission of rupture forces to the periphery that would otherwise cause the second portion to lift or displace. This intermediary structure ensures that the second portion maintains its integrity until the designated higher pressure is reached.
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 allows the gas generator to achieve appropriate output by ensuring that the discharge ports open as intended, maintaining the designed gas generation amount and pressure over time.
Implementation Method 1
a gas generating agent that generates a combustion gas by actuation of the igniter
Implementation Method 2
a portion covering the at least one first discharge port and configured to rupture at a first rupture pressure and a portion covering the at least one second discharge port and configured to rupture at a second rupture pressure higher than the first rupture pressure
Data Source
AI summary
A gas generator includes a housing, one or more first discharge ports provided in the housing and configured to discharge the combustion gas, one or more second discharge ports provided in the housing configured to discharge the combustion gas, and a closing member covering at least one of the one or more first discharge ports and at least one of the one or more second discharge ports together. The closing member includes a portion covering the at least one first discharge port and configured to rupture at a first rupture pressure and a portion covering the at least one second discharge port and configured to rupture at a second rupture pressure, and the closing member includes a breakage assisting portion configured to reduce a strength of the closing member at at least a boundary portion between the at least one first discharge port and the at least one second discharge port.