Airbag Tether Layout for Head Restraint Across Occupant Sizes

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Solution Overview

Problem

Existing airbag designs that deploy in front of occupants can cause ejection of the head, leading to inadequate restraint and potential injury, particularly for different occupant physiques.

Innovation Solution

An airbag device with left and right tethers that regulate the deployed shape, featuring a recess with inclined surfaces and varying tether lengths to enhance restraint performance, minimizing bulging areas and adjusting tension for optimal occupant protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the airbag deploys like a sphere, then the airbag can be简单地 inflated, but the head of the occupant will be ejected and restraint performance deteriorates

Engineering Contradiction:
Improveease of inflationVSAvoidoccupant restraint performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The airbag is divided into multiple regions by tethers: a large deformation region for absorption and a small deformation region for restraint. This segmentation allows different parts of the airbag to serve different functions, resolving the contradiction between simple inflation and effective restraint.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the airbag are given different mechanical properties through the tether configuration. The front region has restricted deformation (small deformation region) for head restraint, while the rear region has free deformation (large deformation region) for energy absorption, creating local quality differences that solve the restraint problem.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If the airbag has large bulging areas, then the airbag can accommodate different occupant sizes, but the chin of small occupants may contact the airbag and cause injury

Engineering Contradiction:
Improveadaptability to different occupant sizesVSAvoidinjury risk to small occupants
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The airbag creates a localized small deformation region at the front with controlled geometry (upper and lower inclined surfaces) that protrudes toward the occupant. This localized structure provides appropriate restraint for small occupants' chins while maintaining overall adaptability through the larger airbag structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The airbag deformation is dynamically controlled by the tether system to create a specific deployment pattern with a recess and inclined surfaces. This dynamic deformation control ensures the airbag adapts to different occupant sizes while preventing harmful contact with small occupants' chins.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If the airbag deploys with uniform tension, then the inflation is simple, but the restraint performance for different occupant physiques is inadequate

Engineering Contradiction:
Improvesimplicity of deploymentVSAvoidrestraint performance for different physiques
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The tether system segments the airbag into regions with different tension characteristics. The tethers create a recess with inclined surfaces that generate non-uniform tension distribution, providing optimized restraint for different occupant physiques while maintaining relatively simple deployment mechanics.

Inventive Principle:
Principle #1Segmentation

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 airbag design effectively restrains occupants' heads by reducing bulging areas and adjusting tension, improving restraint performance regardless of physique, especially for small occupants.

Implementation Method 1

an airbag that expands and deploys toward the occupant by means of expansion gas

Methodology Applied
Scientific EffectExpansion gas:

Implementation Method 2

a left tether and a right tether that are provided inside the airbag and that regulate the deployed shape of the airbag

Methodology Applied
Scientific EffectTension: Tension

Data Source

PatentEP4613571A1Airbag device
Publication Date: 2025.09.10 AUTOLIV DEV AB
  • EP4613571A1 patent drawingFigure 1
  • EP4613571A1 patent drawingFigure 2
  • EP4613571A1 patent drawingFigure 3

AI summary

To provide an airbag device capable of adequately protecting an occupant. The present invention is an airbag device for protecting an occupant inside a vehicle, comprising: an airbag that expands and deploys toward the occupant by means of expansion gas; and a left tether and a right tether that are provided inside the airbag and that regulates the deployed shape of the airbag. The airbag has a front surface facing the occupant, and a right side surface and a left side surface located on either side of the front surface. The front end of the left tether is connected to the inside of the left side surface of the airbag and the rear end is connected to the front surface, and the front end of the right tether is connected to the inside of the right side surface of the airbag and the rear end is connected to the front surface. Furthermore, the airbag has a recess between the right side tether and the left side tether on the front side thereof, the recess being recessed toward the inside of the airbag, and when a cross section passing through the left-right center of the recess and extending in the front-to-back direction of the vehicle is viewed from one side in the left-right direction, an upper inclined surface and a lower inclined surface are formed with the vertical middle part of the recess as a boundary; and the lower inclined surface is configured to protrude more toward the occupant than the upper inclined surface with respect to a vertical line on the cross section passing through the boundary.