Concave Airbag Tether Structure for Knee Deployment Shaping
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Solution Overview
Problem
Airbag cushions often face deployment kinematics issues due to vehicle contours, particularly around the steering column, leading to inadequate protection for the driver's knees, as they may pivot or deflect undesirably and fail to redirect inflation gases effectively to critical regions.
Innovation Solution
An internal tether with concave shapes and vent holes is integrated into the airbag cushion to enhance deployment regions around the knees, redirecting inflation gases and creating enlarged deployment areas while maintaining a reduced thickness between the knees, thereby improving protection and deployment kinematics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the airbag cushion is deployed to cover the steering column area, then the overall protection coverage is improved, but the inflation gas distributes uniformly causing inadequate protection in critical knee regions
Solution Approach 1:
The tether incorporates concave regions at specific locations (first concave region, second concave region, third concave region) that create localized thickness variations in the deployed airbag. These concave regions cause the airbag to be thicker at the knees and thinner between the knees, directing inflation gas to critical protection areas while maintaining overall coverage.
2Strength
If the airbag cushion thickness is increased to provide better protection, then the protective force is improved, but the inflation gas volume required increases and deployment control becomes difficult
Solution Approach 1:
Rather than uniformly increasing thickness, the tether creates localized thickness variations through its concave regions. The airbag is thicker only where needed (at the knees) and thinner in non-critical areas (between the knees), optimizing protective force distribution without requiring excessive inflation gas volume.
3Area of stationary object
If the airbag cushion is designed to cover the space between the knees, then the overall coverage is improved, but the protection effectiveness at the knees is reduced due to gas distribution
Solution Approach 1:
The tether's concave regions create a thickness profile where the airbag is thinner between the knees and thicker at the knees. This local differentiation ensures that coverage is maintained across the entire steering column area while concentrating protective effectiveness at the critical knee regions through localized thickness enhancement.
4Ease of manufacture
If the airbag cushion deploys with uniform thickness, then the manufacturing simplicity is maintained, but the deployment kinematics are poor due to pivoting and deflection
Solution Approach 1:
The tether introduces controlled local variations in thickness through its concave regions, which guide the deployment kinematics. The thinner regions between the knees allow the airbag to conform to the steering column contour, while the thicker regions at the knees provide stable support, preventing unwanted pivoting and deflection.
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 internal tether system ensures enhanced protection for the driver's knees by redirecting inflation gases to critical areas, providing improved deployment characteristics and preventing the knees from sliding off during impacts, thus addressing the limitations of existing airbag cushion designs.
Implementation Method 1
these vent openings may be biased towards the first and second ends to reinforce the effect of the concave shape by directing inflation gases towards the regions configured to deploy adjacent to the occupant's knees
Data Source
AI summary
Airbag cushions and related assemblies comprising improved internal tethers for reshaping deployment. In some embodiments, the assembly may comprise an inflatable cushion and an internal tether comprising an elongated axis positioned within the inflatable cushion, wherein the internal tether comprises a first concave portion attached to a first internal surface of the inflatable cushion and a second concave portion attached to a second internal surface of the inflatable cushion. The first concave portion and the second concave portion may be configured to redirect inflation of the inflatable cushion to form, upon deployment, two enlarged deployment regions and a reduced deployment region between the two enlarged deployment regions.