Airbag Tether Bracket Mechanism for Rotation Control

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Solution Overview

Problem

Conventional side airbag apparatuses fail to sufficiently suppress the rotation of deployed airbags away from the seat due to increased rotational force moments, and require additional components like support plates and brackets, increasing installation time.

Innovation Solution

An airbag apparatus with a tether supported by a bracket attached to the seat back frame, where the tether's other end is attached to the airbag, reducing the rotational force moment and simplifying installation by integrating the bracket with the seat back frame during airbag module attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the side airbag apparatus is installed on the far side distant from the side door, then the airbag deployment space is improved, but the airbag rotation away from the seat increases due to lack of pressure wall

Engineering Contradiction:
Improveairbag deployment spaceVSAvoidairbag rotation control
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

A tether is introduced as an intermediary component to connect the airbag to the seat back frame. The tether acts as a mediator that transmits restraining force from the seat structure to the airbag, preventing rotation away from the seat while allowing the airbag to be installed on the far side for optimal deployment space.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If a tether is coupled only to the airbag and seat without intermediate support, then the device complexity is reduced, but the rotation suppression effectiveness decreases due to increased moment of force

Engineering Contradiction:
Improvetether support structureVSAvoidrotation suppression effectiveness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The bracket serves as an intermediary support structure positioned between the seat back frame and the tether coupling point. This intermediate support reduces the moment arm length, thereby decreasing the moment of force that causes rotation, while maintaining relative simplicity in the overall structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The bracket is pre-installed on the seat back frame at an optimized position before airbag deployment. This preliminary positioning ensures that the tether has the correct attachment geometry to effectively counteract rotational forces during collision, improving reliability without adding complex adjustment mechanisms.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If a support plate and rotatable bracket are added to catch the airbag, then the rotation suppression is improved, but the installation time increases

Engineering Contradiction:
Improveairbag rotation suppressionVSAvoidinstallation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention extracts the essential function of the support plate and rotatable bracket mechanism, retaining only the bracket as a fixed support element. The complex rotatable catching mechanism is removed, keeping only the necessary bracket structure that provides adequate rotation suppression while significantly reducing installation complexity and time.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using a movable support plate that rotates to catch the airbag, the invention inverts the approach by using a fixed bracket that passively provides support. The bracket's fixed position and geometry inherently provide the rotation suppression function without requiring active movement or complex catching mechanisms.

Inventive Principle:
Principle #13The other way round (Inversion)

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

Effectively suppresses airbag rotation away from the seat, improving passenger protection without increasing installation time by using a tether supported by a bracket that acts as the fulcrum, reducing the moment of rotary force.

Implementation Method 1

an inflator provided inside the airbag, which generates gas so as to deploy the airbag

Methodology Applied
Scientific EffectGas generation:

Implementation Method 2

the tether is supported by the front end of the bracket... the moment of force for rotating the tip side of the airbag in the direction away from the seat increases

Methodology Applied
Scientific EffectMoment of force reduction:

Data Source

PatentEP3778312B1Airbag device
Publication Date: 2023.05.24 AUTOLIV DEV AB
  • EP3778312B1 patent drawingFigure 1
  • EP3778312B1 patent drawingFigure 2~3
  • EP3778312B1 patent drawingFigure 4A~4B

AI summary

To effectively retain a deployed airbag without increasing installation man hours, in addition to suppressing rotation of this airbag in a direction away from a seat. For example, a side airbag apparatus 1 installed inside a backrest SB of the seat S includes: an airbag 2; an inflator 3 provided inside the airbag 2; a tether 4; and a bracket 5. The airbag 2 is deployed in a first direction in which a base end side 2a thereof is attached to a seat back frame SBF and the tip side thereof is distant from the backrest SB. The tether 4 includes: one end 4a attached to the seat back frame SBF; and the other end which extends in the first direction on the outer surface of the airbag 2 in the deployed state so as to be attached to the part on the tip side 2b of the airbag 2. A bracket 5 is attached to the seat back frame SBF and provided in the direction in which the tether 4 extends. The tether 4 is supported by the front end of the bracket 5.