Gas Generator Collar Radial Contact Design
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Solution Overview
Problem
Existing gas generators for airbag systems face challenges in maintaining stable output performance due to deformation of the housing during actuation, which can lead to improper contact between igniter cups and disruption of combustion processes.
Innovation Solution
The design incorporates a housing with separate combustion chambers and igniter collars featuring radial plate portions and wall surfaces that face each other, preventing deformation and contact between adjacent components, and optionally uses a spacer to enhance stability during pressure increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the housing structure is simplified for ease of manufacture, then manufacturing cost decreases, but deformation during actuation increases leading to unstable igniter contact
Solution Approach 1:
The housing is divided into a rigid support structure (bottom plate with mounting holes) and a separate combustion chamber structure. The igniter mounting portions are segmented as distinct rigid elements that resist deformation independently from the combustion chamber, allowing the housing to be manufactured in segments and assembled, maintaining both ease of manufacture and structural rigidity where needed.
Solution Approach 2:
The bottom plate is designed with locally reinforced rigid portions at the igniter mounting locations while other areas of the housing can be simpler. The mounting holes and surrounding areas have increased thickness or structural reinforcement to prevent deformation during actuation, while maintaining overall ease of manufacture for non-critical areas.
2Volume of moving object
If the igniter collars are positioned close together to reduce housing size, then volume decreases, but contact between collars during actuation occurs disrupting combustion
Solution Approach 1:
A non-combustible spacer element is introduced between the first and second igniter collars. This spacer maintains a fixed gap that prevents contact between the collars during actuation while allowing the collars to be positioned closer than they would be without the spacer, thus reducing overall housing volume while maintaining combustion stability.
Solution Approach 2:
The spacer is pre-installed between the igniter collars to prevent the harmful action of contact during actuation. By establishing the gap beforehand, the design ensures that even under pressure during combustion, the collars cannot come into contact and disrupt the combustion process.
3Weight of moving object
If the housing walls are made thinner to reduce weight, then weight decreases, but deformation under pressure increases affecting igniter alignment
Solution Approach 1:
The housing is segmented into thin-walled combustion chamber portions and a separate rigid bottom plate structure. The thin walls are used only where structural strength is not critical, while the bottom plate with mounting holes provides rigid support for igniter alignment. This segmentation allows weight reduction in non-critical areas while maintaining precision where needed.
Solution Approach 2:
The housing walls are made thin overall to reduce weight, but the bottom plate and mounting portions have locally increased thickness or rigidity to maintain igniter alignment precision. The critical mounting areas have reinforced structures that resist deformation under pressure, while other housing areas use thin walls for weight reduction.
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 ensures stable output performance by preventing deformation of the housing and maintaining proper alignment of igniter components, thus ensuring consistent combustion and gas generation.
Implementation Method 1
a first gas generating agent accommodated in a first combustion chamber, and ignited and burnt by a combustion product generated by combustion of an ignition agent
Implementation Method 2
ignited and burnt by a combustion product generated by combustion of an ignition agent
Implementation Method 3
a second gas generating agent which are accommodated inside a second combustion chamber cup, and ignited and burnt by a combustion product generated by combustion of an ignition agent in the ignition device chamber
Implementation Method 4
ignited and burnt by a combustion product generated by combustion of an ignition agent
Implementation Method 5
when a pressure inside the housing rises at a time of actuation, the first wall surface of the first igniter and the second wall surface of the second igniter being in contact with each other in a state of being pushed radially inward against each other
Data Source
AI summary
The present invention provides a gas generator including a metallic first collar of a first igniter of an ignition device chamber, which has a first columnar main body portion, a first plate portion extending in a radial direction of a housing from part of a circumferential surface thereof, and a first wall surface formed by extending part of the first plate portion in an axial direction of the housing, a metallic second collar of a second ignition device of a second combustion chamber, which has a second columnar main body portion, a second plate portion extending in the radial direction from part of a circumferential surface thereof and a second wall surface formed by extending part of the second plate portion in the axial direction of the housing, a bottom side of the first columnar main body portion portion of the first collar being fitted in a first hole to fix a first igniter of the ignition device chamber, the first hole being one of two holes formed in the bottom plate of the housing separately from each other in the radial direction, a bottom side of the second columnar main body portion portion of the second collar being fitted in a second hole to fix a second igniter of the second combustion chamber, the second hole being the other one of the two holes formed in the bottom plate separately from each other in the radial direction, further, the first wall surface of the first collar and the second wall surface of the second collar being arranged to face each other in the radial direction, when a pressure inside the housing rises at a time of actuation, the first wall surface and the second wall surface being in contact with each other in a state of being pushed radially inward against each other.