Side Airbag Venting via Tether Cutter

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Solution Overview

Problem

Existing side airbag devices lack an efficient means to adjust internal pressure in response to varying collision speeds, occupant physique, and collision energy, relying on complex and costly inflator modifications.

Innovation Solution

A side airbag device with a vent hole, patch, tether, and tether cutter that adjusts internal pressure by discharging gas based on collision speed and occupant information, using sensors to determine when to cut the tether and open or close the vent hole to optimize restraint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the inflator output is modified to adjust internal pressure according to collision speed, then the restraint performance is improved, but the structure becomes more complicated and cost increases

Engineering Contradiction:
Improverestraint performanceVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the pressure adjustment function from the inflator by introducing a separate vent hole mechanism with a patch and tether system. The inflator remains simple while the vent hole, controlled by the tether-cutter mechanism, handles the adaptive pressure release function based on collision severity detection.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces sensors as intermediary elements that detect collision speed and physical characteristics, then trigger the tether cutter to release the tether, which in turn opens the vent hole. This intermediary detection and control system enables adaptive pressure adjustment without modifying the inflator itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the inflator output is modified to adjust internal pressure according to collision speed, then the restraint performance is improved, but the cost increases

Engineering Contradiction:
Improverestraint performanceVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts the pressure adjustment function from the inflator by introducing a separate vent hole mechanism with a patch and tether system. The inflator remains simple while the vent hole, controlled by the tether-cutter mechanism, handles the adaptive pressure release function based on collision severity detection.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses relatively simple and inexpensive components for the vent hole mechanism (patch, tether, cutter) compared to modifying the inflator. The tether is designed to be cut and discarded after single use, representing a cost-effective approach to achieving adaptive pressure control.

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

3Force

If the airbag cushion is expanded with high internal pressure, then the restraint force is improved, but the injury risk to the occupant increases

Engineering Contradiction:
Improverestraint forceVSAvoidinjury risk
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The patent makes the internal pressure dynamic rather than static. The vent hole remains closed during low-speed collisions to maintain high pressure for effective restraint, but opens during high-speed collisions to reduce pressure and minimize injury risk. This dynamic adjustment is controlled by the tether cutter mechanism responding to collision severity detection.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the pressure parameter of the airbag cushion based on collision conditions. By controlling the vent hole opening state through the tether mechanism, the internal pressure is adjusted according to collision speed and occupant characteristics, optimizing the balance between restraint force and injury prevention.

Inventive Principle:
Principle #35Parameter changes

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 device effectively adjusts internal pressure to optimize occupant restraint, reducing injury risk by matching pressure to collision conditions, thereby enhancing safety without increasing complexity or cost.

Implementation Method 1

an inflator that supplies a gas; an airbag cushion that is expandable from the side toward a front of the vehicle by the gas

Methodology Applied
Scientific EffectGas pressure: Pressure Increase

Implementation Method 2

a tether cutter that is configured to cut the tether in response to information relating to a state of the vehicle

Methodology Applied
Scientific EffectMechanical cutting: Fracture Mechanics

Data Source

PatentEP3459796B1Side airbag device
Publication Date: 2021.01.13 AUTOLIV DEV AB
  • EP3459796B1 patent drawingFigure 1
  • EP3459796B1 patent drawingFigure 2A~2C
  • EP3459796B1 patent drawingFigure 3A~3C

AI summary

[Problems] An object of the present invention is to provide a side airbag device that can adjust an internal pressure of an airbag cushion according to various conditions such as a collision speed, a collision angle, a physique of an occupant, and collision energy at a vehicle collision. [Solving Means] A side airbag device includes: an inflator 110; a cushion 104 that is expandable from the side of a seat 102 toward a front of a vehicle; a vent hole 116 that is provided at a predetermined position of the cushion 104 and that discharges the gas; a patch 122 that openably covers the vent hole 116 from an inside of the cushion 104; a tether 126 that is connected to the patch 122 and a predetermined position (a tether cutter 128) of the side of the seat 102, the tether 126 pulling the patch 122 toward a rear of the vehicle so as to open the vent hole 116 when the cushion 104 is expanded and deployed; and a tether cutter 128 that is configured to cut the tether 126 in response to information relating to a state of the vehicle.