Airbag Igniter Cover Member Reinforcing Rib Design

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Solution Overview

Problem

Existing igniter assemblies for airbag systems face challenges with thin plastic insulation covers that are insufficiently strong, leading to deformation and poor workability during assembly.

Innovation Solution

A cover member with a small wall thickness and reinforcing ribs made from electrically insulating materials like Nylon or fluorine resin, which provides sufficient strength and enhances assembly workability by preventing deformation and ensuring proper fitting with the metallic cup.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the insulation cover is made thin to achieve insulation, then the insulation performance is improved, but the strength is insufficient causing deformation

Engineering Contradiction:
Improveinsulation performanceVSAvoidcover strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The cover member is segmented into multiple peripheral walls instead of a single thick wall. Each peripheral wall can be made thin for insulation, while the collective structure of multiple walls provides the necessary strength and rigidity to prevent deformation during assembly

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cover member uses a composite structure combining multiple thin peripheral walls with insulating material properties. This composite design achieves both insulation performance through the thin walls and structural strength through the multi-wall configuration

Inventive Principle:
Principle #40Composite materials

2Loss of substance

If the insulation cover is made thin to reduce material usage, then the manufacturing cost is reduced, but the assembly workability deteriorates due to deformation

Engineering Contradiction:
Improvematerial usageVSAvoidassembly workability
Core Design Contradiction:
Loss of substanceVSEase of operation

Solution Approach 1:

By dividing the cover into multiple thin peripheral walls, the design uses less material overall while the segmented structure maintains rigidity. This segmentation allows the cover to be assembled without deformation, improving assembly workability despite the reduced material thickness

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cover member employs thin peripheral walls that function as flexible yet sufficiently rigid shells. These thin walls provide the necessary insulation while maintaining enough structural integrity to prevent deformation during handling and assembly operations

Inventive Principle:
Principle #30Flexible shells and thin films

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 cover member with reinforcing ribs improves the assembly workability by maintaining shape under load and preventing deformation, ensuring reliable electrical insulation and secure fitting with the metallic cup, thus enhancing the overall performance of the igniter assembly.

Implementation Method 1

a heating wire (220) extending along the inner circumference of the holder (110), the heating wire (220) being configured to generate heat by self-heating

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP2873942B1Igniter assembly, assembly method thereof, and cover member
Publication Date: 2018.11.14 DAICEL CORP
  • EP2873942B1 patent drawingFigure 1
  • EP2873942B1 patent drawingFigure 2(a)~2(d)
  • EP2873942B1 patent drawingFigure 3(a)~3(d)

AI summary

The present invention provides an igniter assembly, including: an igniter main body, integrated with a resin portion, the igniter main body including: a metallic header having an electro-conductive pin; a metallic cup covering the metallic header so as to form a charging space, an ignition agent charged within the charging space; and a cover member covering the metallic cup, the cover member being provided with a reinforcing rib at least on an inner circumferential surface of a peripheral wall thereof: the igniter assembly including the resin portion surrounding at least a portion of the peripheral wall of the cover member, a portion of the metallic header, and the electro-conductive pin.