Gas Generator Rod Guide Clearance Design
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Solution Overview
Problem
The existing gas generators for airbag systems face issues with the deformation of the partition wall and tube guide, leading to reduced plunger movement and abnormal operation due to uneven pressure distribution, causing the gas generator to malfunction over time.
Innovation Solution
A gas generator design featuring a cylindrical housing with a closing member and a breaking device that includes a base portion and a rod with an enlarged diameter portion, where the rupturable plate is fixed by welding to an annular plate surface portion, and the rod is enclosed by the cylindrical wall portion, ensuring reliable operation by maintaining a gap between the rod and the cylindrical wall portion, allowing for proper movement and collision with the rupturable plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the tube guide extends towards the storage chamber filled with pressurized gas, then the plunger can be guided properly, but the partition wall deforms due to pressure differential causing the tube guide opening to reduce in diameter
Solution Approach 1:
The patent applies beforehand cushioning by designing the tube guide with a specific structural configuration that anticipates and compensates for the pressure-induced deformation. The tube guide is structured to maintain its functional dimensions despite the expected deformation from the pressure differential between the storage chamber and diffuser chamber, ensuring reliable plunger movement throughout the service life of the gas generator.
2Productivity
If the partition wall is designed to separate the storage chamber and diffuser chamber, then gas flow control is achieved, but the partition wall and tube guide deform under large load causing abnormal operation
Solution Approach 1:
The patent applies beforehand cushioning by designing the tube guide with a specific structural configuration that anticipates and compensates for the pressure-induced deformation. The tube guide is structured to maintain its functional dimensions despite the expected deformation from the pressure differential between the storage chamber and diffuser chamber, ensuring reliable plunger movement throughout the service life of the gas generator.
3Manufacturing precision
If the rod is enclosed by the cylindrical wall portion, then the rod movement is guided accurately, but the rod may contact the cylindrical wall causing friction and movement restriction
Solution Approach 1:
The patent applies local quality by creating a specific geometric relationship between the rod and the cylindrical wall portion. The rod has a diameter that is carefully selected to be slightly smaller than the inner diameter of the cylindrical wall portion, creating a small clearance. This local dimensional difference allows the rod to be guided accurately by the cylindrical wall while maintaining smooth movement without excessive friction or contact.
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 design ensures reliable operation of the gas generator over the service life of the vehicle by preventing deformation-induced malfunctions, allowing the rod to move and break the rupturable plate effectively, ensuring consistent gas flow for airbag inflation.
Implementation Method 1
the rupturable plate of the closing member being fixed by welding to the annular plate surface portion of the fixing portion from the pressurized gas chamber
Data Source
AI summary
The present invention provides a gas generator including an ignition device chamber provided with the ignition device, a gas inflow chamber provided with a gas discharge port, and a pressurized gas chamber being arranged in order from the first end; a closing member including a fixing portion and a rupturable plate fixed to the fixing portion and closing between the pressurized gas chamber and the gas inflow chamber; and a breaking device for the rupturable plate being arranged between the ignition device chamber and the gas inflow chamber, the breaking device including a base portion, which has an outer circumferential surface abutted against an inner circumferential wall surface of the cylindrical housing, and a rod extending from the base portion to the rupturable plate, the fixing portion of the closing member including an annular plate surface portion, extending radially inward from the inner circumferential wall surface of the cylindrical housing, and a cylindrical wall portion extending from an inner circumference of the annular plate surface portion towards the gas inflow chamber, the rupturable plate of the closing member being fixed by welding to the annular plate surface portion of the fixing portion from the pressurized gas chamber, the breaking device being disposed such that a tip end of the rod is enclosed by the cylindrical wall portion of the fixing portion of the closing member.