Driver Airbag Sub-Chamber Venting Reduces Abdominal Load

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Solution Overview

Problem

Existing driver airbags often apply significant forces to the upper abdominal region during accidents, and while adaptive ventilation systems provide some protection, they may not offer sufficient adaptivity to accommodate varying driver weights and accident severities effectively.

Innovation Solution

A steering wheel unit with a line-shaped inner connection between the front and back layers, creating a sub-chamber within the main chamber, which is connected via an overflow opening and ventilation holes, allowing for progressive or degressive ventilation characteristics based on pressure and external factors, reducing load on the upper abdominal region.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the airbag chamber is designed as a single large chamber, then the airbag provides sufficient cushioning volume, but it applies excessive force to the upper abdominal region

Engineering Contradiction:
Improveforce on upper abdominal regionVSAvoidairbag chamber volume
Core Design Contradiction:
ForceVSQuantity of substance

Solution Approach 1:

The airbag chamber is divided into a main chamber and a sub-chamber separated by an inner connection. The sub-chamber is positioned in the upper abdominal region and can be independently vented, allowing localized depth reduction in high-risk areas while preserving overall cushioning volume through the main chamber.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If adaptive ventilation is implemented to protect drivers of varying weights, then protection optimality is improved, but device complexity increases

Engineering Contradiction:
Improveadaptivity to driver weightVSAvoidventilation device complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The inner connection is designed as a tear connection that transitions from a closed state to an open state based on internal pressure. This passive dynamic mechanism automatically adapts ventilation to accident severity and driver characteristics without requiring active sensors or control systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The ventilation system uses the airbag's own internal pressure to control the tear connection. When pressure exceeds a threshold, the inner connection automatically tears to open the sub-chamber for venting, eliminating the need for external control mechanisms.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If the inner connection is designed as a tear connection, then progressive ventilation is achieved, but manufacturing precision requirements increase

Engineering Contradiction:
Improveprogressive ventilation characteristicVSAvoidinner connection tear strength
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The inner connection's tear strength is engineered as a specific parameter that can be controlled during manufacturing. By adjusting material properties, seam strength, or geometric features of the inner connection, the tear pressure threshold can be optimized to match target driver populations while maintaining manufacturing feasibility.

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

This design reduces the depth of the airbag in the upper abdominal area, distributing load to the lower ribs and providing adaptive ventilation with a degressive or progressive characteristic, enhancing protection for drivers of varying sizes and weights.

Implementation Method 1

gas can stream from the main chamber through the overflow opening into the sub-chamber and from there out of the ventilation opening

Methodology Applied
Scientific EffectGas flow:

Implementation Method 2

The back layer has at least one ventilation hole connecting the sub-chamber with the environment

Methodology Applied
Scientific EffectVentilation:

Implementation Method 3

A completely deployed driver airbag usually covers the whole steering wheel including its rim. The driver airbag comprises a front layer pointing towards the driver and a back layer pointing towards the steering wheel.

Methodology Applied
Scientific EffectInflation:

Data Source

PatentEP3235692B1Driver airbag and steering wheel unit
Publication Date: 2019.01.30 AUTOLIV DEV AB
  • EP3235692B1 patent drawingFigure 1~2
  • EP3235692B1 patent drawingFigure 3
  • EP3235692B1 patent drawingFigure 4~6

AI summary

A driver airbag which applies only small forces to the upper abdominal region of the driver and which provides additional possibilities of adaptivity is described. This driver airbag comprises a front layer pointing towards the driver when the driver airbag is deployed and a back layer pointing towards the steering wheel when the driver airbag is deployed. Front layer and back layer are circumferentially connected to each other by an edge connection and define a chamber (20). Additionally a line-shaped inner connection (25) connecting the front layer and the back layer in a lower area of the driver airbag is provided. This inner connection encircles at least partially a sub-chamber (23) of the chamber (20), such that the chamber (20) comprises a main chamber (22) and this sub-chamber (23). The back layer has at least one ventilation hole which connects the sub-chamber (23) with the environment (Fig. 4).