Airbag Vent Slit Design for Pressure Control
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Solution Overview
Problem
The existing airbag apparatus has a complex structure due to the sewing of the vent hole cover, which limits cost reduction and efficiency in rapidly expanding the airbag to a high-pressure state and suppressing excessive pressure when an occupant is constrained.
Innovation Solution
An airbag apparatus with a vent hole configured as a slit between the outer and central portions of two superimposed base cloths, which closes during expansion to maintain high pressure and opens when constrained to release gas, allowing for simple manufacturing and extended effect duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vent hole cover is sewn to the airbag at multiple spiral sewing portions, then the vent hole can be closed during expansion, but the sewing portion structure becomes complicated
Solution Approach 1:
The invention extracts the vent hole cover and its complex spiral sewing portions from the airbag structure. Instead of sewing a separate cover component, the vent hole is formed directly as a slit in the airbag body, eliminating the need for additional covering parts and their associated complex sewing operations.
Solution Approach 2:
The invention merges the vent hole cover function with the airbag body itself by forming the vent hole as a slit directly in the airbag material. This integration eliminates the separate cover component and simplifies the overall structure while maintaining the venting function.
2Strength
If thick threads are used for the outermost sewing portion, then the sewing portion does not rupture during expansion, but the structure becomes more complex and costly
Solution Approach 1:
The invention removes the outermost sewing portion that required thick threads for reinforcement. By forming the vent hole as a slit and eliminating the separate vent hole cover and its sewing attachments, the need for varied thread specifications is removed entirely.
3Ease of operation
If slender threads are used for inner sewing portions, then the sewing portion ruptures to open the vent hole, but the structure becomes complicated
Solution Approach 1:
The invention extracts and eliminates the complex sewing portion structure that used slender threads for controlled rupture. The vent hole is formed as a simple slit in the airbag body, removing the need for differentiated thread specifications and complex sewing patterns.
Solution Approach 2:
Instead of using sewing portions that are designed to rupture (with slender threads) to open the vent hole, the invention inverts the approach by forming the vent hole as a pre-existing slit that is naturally opened by the airbag's expansion and deformation during deployment.
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 apparatus rapidly expands to a high-pressure state and effectively suppresses excessive pressure when constrained, with a simple structure that reduces manufacturing costs and prolongs the airbag's effectiveness.
Implementation Method 1
an inflator which introduces gas to an inside of the airbag body
Implementation Method 2
when gas is introduced to the airbag body, the airbag body inflates in a normal direction of the base cloths, and also, an outer diameter thereof is decreased. Subsequently, the slit is closed.
Implementation Method 3
when an occupant is constrained by the airbag body after the airbag body expands, the airbag body is pressed by the occupant along the normal direction of the base cloth, and also, an outer diameter thereof is increased. Subsequently, the slit is opened and functions as a vent hole.
Data Source
AI summary
An airbag apparatus for vehicle includes: an airbag body formed by joining outer peripheral portions of two base cloths, the two base cloths being superimposed on each other; an inflator introducing gas to an inside of the airbag body; and a vent hole formed on the airbag body and configured of a slit, the vent hole communicating between the inside and an outside of the airbag body, the slit being formed so as to be directed from the outer peripheral portions toward central portions of the two base cloths over the two base cloths.