Airbag Venting with Peel Tether Dynamics
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Solution Overview
Problem
Conventional airbag systems face challenges in providing optimal protection during collision events, particularly for out-of-position occupants, as they either underinflate or overinflate, leading to inadequate resistance and potential injury.
Innovation Solution
The airbag system incorporates a venting assembly with adjustable venting capacity, featuring a first vent that increases gas exit during initial deployment to reduce initial resistance and then restricts gas exit as pressure builds, ensuring adequate resistance during occupant ride-down by transitioning through various tether configurations and vent states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the airbag inflates rapidly to provide adequate resistance during collision, then protection effectiveness is improved, but initial impact forces on out-of-position occupants increase causing potential injury
Solution Approach 1:
The venting assembly transitions from a static vent configuration to a dynamic system where the vent state changes based on inflation pressure. Initially, the vent is in a first state allowing high venting capacity to reduce impact forces. As pressure builds, the peel tether releases and the vent transitions to a second state with restricted venting capacity, enabling the airbag to provide adequate resistance for normal occupants.
Solution Approach 2:
The system changes the venting capacity parameter dynamically during inflation. The venting assembly has different vent states (first state with high capacity, second state with restricted capacity) that are activated based on inflation pressure levels. This parameter change allows the airbag to adapt its characteristics during the collision event, reducing initial impact forces while maintaining subsequent protection effectiveness.
2Device complexity
If the airbag uses a fixed venting capacity, then device complexity is reduced, but it cannot provide optimal protection for both out-of-position and normally positioned occupants
Solution Approach 1:
The venting assembly operates autonomously based on inflation pressure without requiring external control systems. The peel tether automatically releases when the inflation pressure exceeds the threshold, causing the vent to transition from the first state to the second state. This self-service mechanism provides adaptability for different occupant positions while avoiding complex electronic controls or sensors.
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 adaptive venting mechanism enhances protection by minimizing initial impact forces on out-of-position occupants while maintaining sufficient resistance during the ride-down phase, thereby reducing injury risk across different collision scenarios.
Implementation Method 1
an inflatable chamber (112) configured to receive inflation gas and pressurize the airbag cushion
Implementation Method 2
a venting assembly (120) configurable in different states during deployment of the airbag assembly and controlling a flow of inflation gas exiting the airbag assembly
Data Source
AI summary
Airbag assemblies and vents are disclosed. An airbag assembly includes an airbag cushion and a vent assembly including a vent, one or more sheer tethers, and a peel tether. The sheer tether(s) are configured to be drawn to a taut state by expansion of the airbag cushion to configure the vent in a first venting state. The sheer tether(s) are releasably coupled to the peel tether. The releasable coupling is configured to maintain the sheer tether(s) releasably coupled to the peel tether. The peel tether is configured to transition from a slack state to a taut state as the airbag cushion continues to expand. The peel tether drawn taut produces a peel force transverse to the sheer force. The peel force causes the releasable coupling to release and the peel tether to uncouple from the sheer tether(s), to transition the vent to a second state.