Gas Generator Grounding via Electro-Conductive Member
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Solution Overview
Problem
Conventional gas generator modules face issues with static electricity accumulation due to insulation from the vehicle body, leading to unwanted ignition, as the metallic housing is electrically isolated from the module case and vehicle body, preventing effective discharge of electric charges.
Innovation Solution
A gas generator-module case assembly that includes an annular electro-conductive member acting as a ground terminal, connected to a metallic cylindrical fixing member and a connector, allowing electric charges to flow to a ground circuit via a grounded lead wire, ensuring safe discharge of static electricity even when a resin material is present between the gas generator housing and the module case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a resin material is installed between the gas generator housing and the module case to prevent steering wheel resonance, then vibration damping is improved, but electrical insulation increases causing static charge accumulation
Solution Approach 1:
The electrical connection path is segmented into multiple components: the electro-conductive member (first segment), the metallic cylindrical fixing member (second segment), and the grounded lead wire (third segment). This segmentation allows the resin insulation layer to be present while maintaining electrical continuity through the distributed conductive elements.
Solution Approach 2:
The electro-conductive member acts as an intermediary element that bridges the gap created by the resin insulation. It provides a dedicated electrical pathway from the gas generator housing to ground, mediating between the insulating resin and the grounding requirement.
2Object-affected harmful factors
If the metallic housing is electrically insulated from the module case using rubber or resin, then unwanted resonance is prevented, but electric charge discharge is blocked causing ignition risk
Solution Approach 1:
The electro-conductive member and metallic fixing member are pre-installed and positioned to ensure electrical continuity before the gas generator is fully assembled and before static charge accumulation becomes a hazard. This preliminary electrical connection prevents the ignition risk from arising in the first place.
Solution Approach 2:
The resin material, which causes the harmful effect of electrical insulation, is accepted as necessary for vibration damping. The invention converts this harmful insulation effect into a manageable condition by adding separate electro-conductive grounding elements that bypass the insulation, allowing the resin to fulfill its vibration damping function while the conductive elements handle the electrical discharge function.
3Reliability
If direct metal-to-metal connection is maintained between gas generator and module case, then electrical grounding is ensured, but vibration resonance increases
Solution Approach 1:
The mechanical connection and electrical connection functions are segmented into separate components. The resin material handles the mechanical vibration damping, while the electro-conductive member and metallic fixing member handle the electrical grounding, eliminating the need for direct metal-to-metal contact.
Solution Approach 2:
The metallic cylindrical fixing member serves multiple functions: it mechanically secures the igniter assembly, provides an electro-conductive path for grounding, and structurally connects different components. This multi-functionality eliminates the need for separate dedicated grounding elements.
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
Prevents unwanted ignition by effectively grounding the metallic housing, ensuring that static electricity is safely discharged, thereby preventing malfunctions caused by electric charge accumulation.
Implementation Method 1
an annular electro-conductive member which is in contact with a cylindrical part and an annular part of the closure shell to serve as a ground terminal
Data Source
AI summary
The present invention provides a gas generator (1) including a metallic housing (10), with an igniter assembly including an igniter main body (14) fixed to a metallic cylindrical fixing member (12a, 12b) with a resin and a connector-connecting portion (40) for fitting a connector (60), at least part of the metallic cylindrical fixing member (12a, 12b) being electro-conductive to the housing (10), and including an exposed portion (30a) exposed to an inner surface of the connector-connecting portion, the exposed portion (30a) serving as a ground terminal, wherein when the connector is connected to the connector-connecting portion, the ground terminal is in contact with an earth terminal (63) of the connector, a grounding lead wire of the connector being grounded to a ground circuit located outside the gas generator.