Gas Generator Multifunctional Member for Rapid Airbag Inflation
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Solution Overview
Problem
Existing gas generators in air bag systems experience prolonged time delays between activation and gas discharge due to the need for rupture of the closure member, which hampers prompt activation of restraining devices.
Innovation Solution
A gas generator design incorporating a multifunctional member with a base plate and cylindrical wall portion that holds and ruptures the closing member, securing a gas discharge path and supporting the gas generating agent, allowing for immediate combustion gas and pressurized gas discharge through strategically placed through-holes and plenum chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a closing member is used to seal the pressurized gas chamber, then gas discharge path integrity is maintained, but activation time is prolonged due to rupture delay
Solution Approach 1:
The closing member is pre-formed with a fragile portion at a specific location, preparing it for controlled rupture. This preliminary structural preparation ensures that when activation occurs, the rupture happens immediately at the predetermined weak point rather than requiring time for the closing member to fail unpredictably, thus reducing activation time while maintaining seal integrity during normal operation
Solution Approach 2:
The closing member is designed with non-uniform structure by incorporating a fragile portion with reduced thickness or strength at a specific location. This local quality change allows the closing member to maintain overall structural integrity for sealing while having a specific weak point that ruptures quickly upon activation, resolving the contradiction between maintaining seal reliability and enabling rapid gas discharge
2Speed
If a multifunctional member is introduced to hold and rupture the closing member, then gas discharge speed is improved, but device complexity increases
Solution Approach 1:
The multifunctional member is designed to perform multiple functions: it supports the closing member in its initial sealed position, guides the rupture process by concentrating force on the fragile portion, and facilitates rapid gas discharge. By consolidating these functions into a single component rather than using separate elements, the design achieves fast gas discharge speed while minimizing the increase in device complexity
Solution Approach 2:
The multifunctional member combines the support function and rupture initiation function into a single integrated component. Instead of using separate support structures and rupture mechanisms, the design merges these functions into one element that both holds the closing member and actively participates in its controlled rupture, thus improving gas discharge speed without proportionally increasing structural complexity
3Reliability
If the closing member is made stronger to maintain seal integrity, then reliability is improved, but activation difficulty increases
Solution Approach 1:
The closing member is designed with differential structural properties: the majority of the closing member maintains sufficient strength and thickness to ensure reliable sealing integrity, while a specific fragile portion has reduced thickness or strength to enable easy rupture. This local quality differentiation allows the seal to be strong overall while having a predetermined weak point that facilitates simple activation
Solution Approach 2:
The fragile portion is pre-formed during manufacturing with reduced strength characteristics, preparing the closing member for easy rupture at a specific location. This preliminary structural preparation ensures that during activation, the closing member can be ruptured easily at the predetermined point without requiring excessive force, while the rest of the closing member maintains sufficient strength for reliable sealing
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
Enables rapid and reliable gas discharge upon activation, ensuring prompt inflation of air bags and maintaining high performance throughout the vehicle's service life by minimizing delays and ensuring secure gas path integrity.
Implementation Method 1
combustion gas generated by combustion of the gas generating agent
Implementation Method 2
the pressurized gas inside the pressurized gas chamber housing entering the first plenum chamber from an opening portion obtained by rupture of the closing member, passing through the second through-hole and the second plenum chamber, and then being discharged from the gas discharge port
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The present invention provides a gas generator(10), including: a cylindrical ignition device chamber housing(20) provided with a gas discharge port(27), accommodating an igniter(25) and a gas generating agent(38) therein, a cylindrical pressurized gas chamber housing(40) filled with pressurized gas, the cylindrical pressurized gas chamber housing being joined to the ignition device chamber housing(40) to form an outer shell container; a closing member(12) being provided with a fragile portion(11) and closing between the ignition device chamber housing(20) and the pressurized gas chamber housing (40) ; a multifunctional member(30) that is movable in an axial direction during activation being arranged inside the ignition device chamber housing(20) together with the igniter(25) and the gas generating agent(38), the igniter(25) closing an opening portion of the ignition device chamber housing(20) and being fixed thereto; the multifunctional member(30) having, a base plate portion(31) and a cylindrical wall portion(32) extending from one surface of the base plate portion(31), the cylindrical wall portion(32) having an opening portion at a distal end thereof the base plate portion(31) abutting against an inner wall surface(21) of the ignition device chamber housing(20) and having a first through-hole(33) in a thickness direction, and the cylindrical wall portion(32) having a smaller outer diameter than an outer diameter of the base plate portion(31), and being provided with a second through-hole(34) in the thickness direction thereof, the opening portion abutting against the fragile portion(11) of the closing member(12); a first plenum chamber(35) enclosed by the base plate portion(31), the cylindrical wall portion(32) and the closing member(12); a second plenum chamber(36) formed by a cylindrical space between an outer wall surface of the cylindrical wall portion(32) and the inner wall surface(21) of the ignition device chamber housing, and the gas discharge port(27) being provided in a circumferential wall portion of the ignition device chamber housing(20), to face the second plenum chamber(36); a gas generating agent charging chamber(37) enclosed by the base plate portion(31), the igniter(25), and the inner wall surface(21) of the ignition device chamber housing and charged with the gas generating agent(38), by pressure increase inside the ignition device chamber housing(20) due to combustion gas generated by combustion of the gas generating agent(38), the multifunctional member(30) being moved in the axial direction to rupture the closing member(12), the combustion gas passing through the first through-hole(33), the first plenum chamber(35), the second through-hole(34) and the second plenum chamber(36), and then being discharged from the gas discharge port(27), the pressurized gas inside the pressurized gas chamber housing(40) entering the first plenum chamber(35) from an opening portion obtained by rupture of the closing member(12), passing through the second through-hole(34) and the second plenum chamber(36), and then being discharged from the gas discharge port(27).