Airbag Diffuser with Tension-Actuated Outlet Closure
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Solution Overview
Problem
Conventional airbag devices experience delayed closure of the lower chamber outlet port and reduced inner pressure due to the extended design of the gas distributor and check valve, leading to inefficient inflation and deployment during side collisions.
Innovation Solution
An airbag device with a diffuser that partitions the airbag into two chambers, where the outlet ports are connected to the opposing base cloths, allowing the gas to flow and then narrowing and closing due to tension from the connected cloth, facilitating early closure and maintaining high pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the outlet port of the gas distributor for the lower chamber is extended toward the side of the lower chamber to prevent gas flow, then gas leakage is prevented, but the closure of the outlet port is delayed and inner pressure decreases
Solution Approach 1:
The gas distributor is divided into multiple outlet ports with different structures: the upper chamber outlet port has a check valve for one-way gas flow control, while the lower chamber outlet port uses a closure structure that closes after inflation. This segmentation allows each outlet port to be optimized for its specific function, resolving the contradiction between preventing gas leakage and achieving timely closure.
Solution Approach 2:
The lower chamber outlet port is designed to close automatically after the lower chamber completes its inflation. The closure action is triggered by the inflation process itself, where the gas distributor body moves relative to the lower chamber, causing the outlet port to close. This preliminary closure action prevents gas leakage while maintaining high inner pressure, as the closure occurs immediately after inflation rather than being delayed.
2Device complexity
If the gas distributor is formed with a cloth wrapped in a cylindrical shape, then the structure is simple, but the outlet port closes gradually from a cylindrically expanded state which delays sealing and pressure maintenance
Solution Approach 1:
The gas distributor is segmented into distinct functional zones: the diffuser portion with a specific shape for gas flow distribution, and the outlet port portions with specialized closure mechanisms. The lower chamber outlet port includes a closure structure that is integrated into the gas distributor body, allowing it to close rapidly after inflation. This segmentation enables the gas distributor to maintain a relatively simple overall structure while achieving rapid sealing through the specialized outlet port design.
3Speed
If the outlet port size for the lower chamber is made larger to supply gas quickly, then inflation speed increases, but the outlet port takes longer to close and inner pressure is reduced
Solution Approach 1:
The lower chamber outlet port is designed with dynamic closure characteristics: it remains open with a large effective area during the inflation phase to enable rapid gas supply and high inflation speed, then closes automatically after inflation is complete. The closure is achieved through the relative movement between the gas distributor body and the lower chamber, which causes the outlet port to seal. This dynamic behavior allows the system to achieve both fast inflation and timely closure, resolving the contradiction between inflation speed and closure timing.
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
Enables early initiation and completion of air chamber closure, maintaining high inner pressure for extended protection during side collisions without increasing the number of parts in the airbag device.
Implementation Method 1
a gas generator for supplying a gas to the airbag and inflating and deploying the airbag
Implementation Method 2
the opening narrows gradually and closes by a tension imposed from the connected cloth in conjunction with the inflation of the airbag
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
Closing movement of at least one of two or more air chambers is started at an early stage, and an inflated air chamber is tightly closed and maintained in an inflated state for a long time. Inside of an airbag (20) is partitioned into air chambers (21), (22) with a partitioning cloth (33), and a diffuser (40) that stores a gas generator (50) is disposed in the air chambers (21), (22) through the partitioning cloth (33). Gas from a gas generator (50) is rectified by the diffuser (40), and is supplied from outlet parts (43),(44) into the air chambers (21),(22), thereby inflating and deploying the air chambers (21),(22). An occupant side base cloth (42), a semi-perimeter portion around the lower outlet part(43), is connected to a back-side base cloth (31) of the airbag (20), and in accordance with an inflation of the lower air chamber (21), a tension is imposed on the occupant side base cloth (42) from the back-side base cloth (31) thereby elongating the lower air chamber (43) . This causes the base cloths (41), (42) to come close to each other and gradually narrow the opening width, thereby enabling the base cloths (41), (42) to closely stick to each other so as to close the opening of the lower outlet part (43).