Airbag Vent Opening Control Using a Single Tether

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Solution Overview

Problem

Existing airbag devices have complex structures that require costly components like cylindrical opposing sheets, which complicate the internal pressure adjustment mechanism and hinder cost-effective improvements in occupant restraint performance and safety.

Innovation Solution

A simplified airbag device structure utilizing a first tether that becomes taut during expansion to reduce the gas discharge section opening, and relaxes upon occupant contact to increase discharge, thereby maintaining internal pressure and reducing occupant load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a cylindrical opposing sheet part and two tethers are used to adjust internal pressure, then gas discharge control is improved, but device complexity increases and manufacturing cost rises

Engineering Contradiction:
Improvegas discharge controlVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the essential function of the complex cylindrical opposing sheet mechanism and implements it using only a single tether element. The tether is directly connected to the gas discharge hole, eliminating the need for the cylindrical sheet and its associated tethers, while still achieving the desired gas discharge control through the tether's tension state

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The single tether in the patent performs multiple functions: it controls the gas discharge hole opening, maintains airbag shape during expansion, and adjusts internal pressure. This multi-functional design replaces the specialized cylindrical opposing sheet mechanism, reducing component count while maintaining gas discharge control reliability

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If a cylindrical opposing sheet part protrudes and expands from the airbag, then internal pressure adjustment is achieved, but manufacturing cost increases

Engineering Contradiction:
Improveinternal pressure adjustmentVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the expensive cylindrical opposing sheet component with a simple, inexpensive tether element. The tether is a basic structural component that can be manufactured at low cost using standard materials and processes, significantly reducing manufacturing expenses while maintaining the internal pressure adjustment function

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent removes the costly cylindrical opposing sheet part from the design and retains only the essential tether element needed for pressure adjustment. This extraction of the core function eliminates unnecessary complexity and reduces manufacturing costs associated with producing and assembling the cylindrical component

Inventive Principle:
Principle #2Taking out (Extraction)

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 simplified structure achieves improved occupant restraint performance and safety by economically implementing a mechanism that adjusts gas discharge based on occupant interaction, enhancing both cost-effectiveness and safety features.

Implementation Method 1

Upon completion of expansion and deployment, the first tether of the airbag cushion is taut and the area of the gas discharge section opening is reduced

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

when the occupant comes into contact with the occupant side panel of the chamber, the first tether relaxes, increasing the area of the gas discharge section opening

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4155136B1Vehicular airbag device
Publication Date: 2026.01.28 AUTOLIV DEV AB
  • EP4155136B1 patent drawingFigure 1(a)~1(b)
  • EP4155136B1 patent drawingFigure 2(a)~2(b)
  • EP4155136B1 patent drawingFigure 3(a)~3(b)

AI summary

Problem Provide an airbag device for a vehicle with a simple structure having improved occupant restraint performance and improved safety. RESOLUTION MEANS The airbag cushion 104 includes a gas discharge section 120, a first tether 124, and a chamber having an occupant side panel 114 and a steering wheel side panel 116. The first tether 124 includes a first end 126 directly or indirectly connected to the occupant side panel 114 and second ends 128a, 128b connected to the steering wheel side panel 116. The edge of the gas discharge section 120 can be pulled into the chamber 105 by the taut first tether 124 and the area of the gas discharge section 120 opening with the edge of the gas discharge section 120 pulled into the chamber 105 is smaller than when the first tether 124 is relaxed.