Airbag Diffuser Temporary Stitching Alignment

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Solution Overview

Problem

The existing mass production processes for airbag devices require specialized jigs for temporary stitching of airbag cushions and diffusers, increasing costs and labor, and leading to quality control issues.

Innovation Solution

A driver's side airbag device configuration that includes a temporary stitched part between the diffuser and the airbag cushion's occupant side panel, which is breakable by gas pressure, allowing for simpler alignment and stable deployment without the need for dedicated jigs, using markings for alignment and orthogonal or intersecting lines for efficient stitching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a special jig is used for temporary stitching of the airbag cushion and diffuser in mass production, then the stitching precision and alignment can be controlled, but the production cost and labor requirements increase

Engineering Contradiction:

Improvestitching precisionVSAvoidproduction cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The diffuser is designed with self-aligning features including a projecting portion that fits into a recess on the airbag cushion, and marking lines that guide the stitching position. This self-alignment mechanism eliminates the need for expensive specialized jigs while maintaining stitching precision through inherent geometric constraints and visual guides.

Inventive Principle:

Principle #25Self-service

2Manufacturing precision

If a special jig is used for temporary stitching, then quality variation can be controlled, but labor and time requirements increase

Engineering Contradiction:

Improvequality consistencyVSAvoidproduction time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The diffuser is pre-equipped with alignment features including a projecting portion and marking lines during the manufacturing process. These preliminary preparations enable workers to quickly align and stitch the diffuser to the airbag cushion without requiring time-consuming jig setup, thereby maintaining quality consistency while reducing production time.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If the diffuser is temporarily stitched to the airbag cushion without alignment features, then the production process is simpler, but the diffuser may become misaligned during stowage and deployment

Engineering Contradiction:

Improveproduction simplicityVSAvoiddiffuser alignment stability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The alignment system is segmented into distinct functional elements: a projecting portion on the diffuser that fits into a recess on the airbag cushion for mechanical positioning, and marking lines that provide visual guidance. This segmentation allows the alignment function to be integrated into the components themselves without complicating the overall production process.

Inventive Principle:

Principle #1Segmentation

4Productivity

If orthogonal or intersecting lines are used for temporary stitching across the supply port, then the stitching can be efficiently broken by gas pressure, but the stitching pattern becomes more complex

Engineering Contradiction:

Improvedeployment efficiencyVSAvoidstitching pattern complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The stitching pattern is designed with local quality variation: orthogonal or intersecting lines are concentrated specifically across the circular supply port area where gas pressure is highest, while other areas use simpler stitching. This localized complexity ensures efficient stitch breaking where needed without unnecessarily complicating the overall stitching pattern.

Inventive Principle:

Principle #3Local quality

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 simplifies the stitching process, stabilizes the diffuser and airbag cushion positions during deployment, ensures consistent quality, and reduces production costs while improving occupant restraint performance.

Implementation Method 1

an inflator that supplies gas to the airbag cushion

Methodology Applied

Scientific EffectGas expansion:

Implementation Method 2

a diffuser that is contained in the airbag cushion and straightens gas flow from the inflator

Methodology Applied

Scientific EffectGas flow straightening:

Implementation Method 3

a temporary stitched part that is breakably sewn between the diffuser and the prescribed location of the occupant side panel of the airbag cushion, across the occupant side supply opening of the diffuser

Methodology Applied

Scientific EffectPressure-induced fracture: Fracture Mechanics

Data Source

PatentUS11472363B2Driver's side airbag device

Publication Date: 2022.10.18 AUTOLIV DEV AB

AI summary

A driver's side airbag device 100 is provided with a diffuser 124 that is contained in an airbag cushion 104 and straightens gas flow from an inflator 112. The diffuser 124 has a connecting part 136 that is connected to the inflator 112 and one or a plurality of supply ports that supply gas received from the inflator 112 into the airbag cushion 104. The supply ports include a passenger side supply port 148 that overlaps at a predetermined location of the occupant side panel 120 of the airbag cushion 104 with the diffuser 124 contained therein. The driver's side airbag device 100 is further provided with a temporary stitched part 150 that breakably stitches the diffuser 124 and a predetermined portion of the occupant side panel 120 of the airbag cushion 104 across the occupant side supply opening 148 of the diffuser 124.