Gas Generator Gastight Container Swaged Joint Strength
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Solution Overview
Problem
The existing gas generators with gastight containers formed from weak members, joined using methods like brazing, adhesion, or winding, suffer from insufficient joint strength, leading to potential breakage under external forces and compromised sealing performance.
Innovation Solution
A gas generator design featuring a gastight container with a cup body and cover body, where the cover body has a fold-over portion with swaging portions to enhance the joint strength, and an elastic biasing mechanism to maintain sealing integrity, ensuring the gas generating agent remains hermetically sealed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If brazing, adhesion, welding, or tightening by winding is used to join the cup body and cover body, then the gastight container can be assembled, but the joint strength is insufficient and the gastight container may break due to external force
Solution Approach 1:
The patent changes the joining method from conventional brazing, adhesion, or winding to a swaging process. The swaging process applies radial compressive force to deform the cup body and cover body together, creating a mechanically interlocked joint with superior strength that can withstand external forces during air bag deployment.
Solution Approach 2:
The patent replaces chemical joining methods (brazing, adhesion) with a mechanical deformation method (swaging). The swaging process uses controlled plastic deformation of the metal components to create a permanent, strong joint that is mechanically superior to conventional joining methods.
2Reliability
If the gastight container is made from relatively weak members to allow melting or bursting with heat/pressure, then the container can release gas generating agent, but the joint portion breaks under external force
Solution Approach 1:
The patent applies different properties to different parts of the gastight container. The cup body and cover body are made from relatively weak members that can melt or burst with heat/pressure generated by the igniter, while the swaged joint portions are strengthened through plastic deformation to withstand external forces during assembly and deployment.
Solution Approach 2:
The swaging process is performed in advance during assembly to pre-strengthen the joint portions before the gastight container is subjected to external forces. This preliminary mechanical reinforcement ensures that the joints can withstand handling and deployment forces while maintaining the intended weak property for controlled rupture during activation.
3Device complexity
If conventional joining methods are used, then assembly is simple, but sealing performance lowers due to joint breakage
Solution Approach 1:
The patent combines the joining function and strengthening function into a single swaging operation. The swaging process simultaneously joins the cup body and cover body while pre-strengthening the joint portions, eliminating the need for separate joining and strengthening steps while maintaining construction simplicity.
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 achieves high sealing performance and desired gas output with a simplified construction, preventing joint breakage and maintaining hermetic sealing even under external forces.
Implementation Method 1
a first swaging portion formed by decreasing a diameter of the fold-over portion radially inward and a second swaging portion formed by decreasing a diameter of the fold-over portion radially inward
Implementation Method 2
an elastic biasing mechanism to maintain sealing integrity
Implementation Method 3
melts or bursts with heat or a pressure generated by activation of the igniter
Implementation Method 4
melts or bursts with heat or a pressure generated by activation of the igniter
Data Source
AI summary
A gas generator includes a housing and a gastight container which accommodates a gas generating agent. The gastight container includes a cup body and a cover body. The cover body includes a bottom portion and a fold-over portion which covers an opening end of the cup body. The cover body is fixed to the cup body by providing, in the fold-over portion in a portion covering an outer circumferential surface of the opening end of the cup body, a first swaging portion in a portion of the fold-over portion which corresponds to a sidewall portion of the cup body and defines a gas generating agent accommodation chamber at a position adjacent to the bottom portion and a second swaging portion in a portion opposed to a portion of the fold-over portion which covers an inner circumferential surface of the opening end of the cup body.