Two-Cavity Airbag Folding for Stable Sequential Inflation

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Solution Overview

Problem

Existing safety airbags face challenges in maintaining inflation stability, which can lead to inadequate protection or injury to vehicle occupants due to improper inflation or positioning.

Innovation Solution

The safety airbag design includes a first airbag cavity with a fixed end and a free end that folds towards the fixed end, and a second airbag cavity with bilaterally symmetrical structure and N-shaped fold portions, allowing for controlled inflation speed and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the overhead safety airbag is inflated quickly to provide immediate protection, then the response time is reduced, but the inflation trajectory becomes difficult to control and may cause injury to occupants

Engineering Contradiction:
Improveinflation speedVSAvoidinflation stability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The airbag is divided into a first airbag cavity and a second airbag cavity that inflate in sequence. The first cavity provides initial inflation to position the airbag, while the second cavity completes the inflation process, enabling controlled staged deployment that maintains both speed and stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first airbag cavity is inflated before the second airbag cavity to preliminarily position the airbag in the correct trajectory. This preliminary action ensures that the subsequent inflation of the second cavity occurs in a controlled manner, preventing uncontrolled rapid expansion that could injure occupants.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the safety airbag is placed in the roof to allow design flexibility of steering wheel and dashboard, then the design freedom is improved, but the control of inflation trajectory becomes more difficult

Engineering Contradiction:
Improvedesign flexibilityVSAvoidtrajectory control
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The airbag system is segmented into two cavities with different functions. The first cavity controls the initial deployment trajectory from the roof, while the second cavity ensures proper positioning and cushioning, thereby maintaining trajectory control despite the flexible roof mounting position.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first airbag cavity performs the preliminary action of establishing the correct inflation trajectory from the roof position. This ensures that even with design flexibility in steering wheel and dashboard positioning, the airbag follows a controlled path during deployment.

Inventive Principle:
Principle #10Preliminary action

3Volume of moving object

If the safety airbag enters the space reserved for the occupant during inflation, then the protection coverage is improved, but the likelihood of injury to occupants increases

Engineering Contradiction:
Improveprotection coverageVSAvoidinjury risk
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The inflation process is segmented into two phases corresponding to the two airbag cavities. The first cavity expands to establish proper positioning and trajectory, while the second cavity provides the remaining protection coverage. This segmentation ensures that the airbag achieves full coverage without uncontrolled intrusion into the occupant space.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first airbag cavity performs the preliminary action of positioning the airbag along the correct trajectory before the second cavity completes the expansion. This preliminary positioning prevents the airbag from directly intruding into the occupant's space during the main inflation phase, reducing injury risk while maintaining protection coverage.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4112395B1Airbag and folding method for airbag
Publication Date: 2025.04.23 AUTOLIV DEV AB
  • EP4112395B1 patent drawingFigure 1
  • EP4112395B1 patent drawingFigure 2A~2G
  • EP4112395B1 patent drawingFigure 3A~3G

AI summary

A safety airbag (10) and a folding method for a safety airbag (10). The safety airbag (10) includes a first airbag cavity (100) and a second airbag cavity (200). The second airbag cavity (200) is arranged on a panel of the first airbag cavity (100). When the safety airbag (10) is in an inflated state, the size of the second airbag cavity (200) in a first direction (V) is smaller than the size of the first airbag cavity (100) in the first direction (V). The first airbag cavity (100) has a left part (130) and a right part (140) that are arranged in a second direction (H). When the safety airbag (10) is in a stowed state, the left part (130) and the right part (140) are folded inwards to form a left covering part (1301) and a right covering part (1401). The left covering part (1301) and the right covering part (1401) are each configured to cover part of the second airbag cavity (200) so as to completely cover the second airbag cavity (200) from the left and right sides. The second direction (H) is different from the first direction (V), thereby enabling effective control of the inflation speed of the second airbag cavity (200), such that the second airbag cavity (200) can be inflated after being located at a desired operating position so as to improve the stability of the safety airbag (10) during expansion and inflation.