Floor-Deployed Leg Airbag With 3D Tubular Support Struts
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Solution Overview
Problem
In vehicle interiors with ample legroom, existing knee airbags struggle to effectively protect occupants' legs from swinging upwards during collisions, especially in autonomous driving scenarios where seating positions are more flexible.
Innovation Solution
A vehicle occupant protection system featuring a foldable airbag with tubular inflatable chambers connected three-dimensionally, forming support struts and a restraint chamber, which deploys from the floor to provide comprehensive leg protection without additional vehicle support surfaces, utilizing a one-piece weaving method (OPW) for efficient manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional knee airbags are used in vehicles with ample legroom, then the airbag can be deployed, but the protection effectiveness is insufficient because the legs can still swing upwards freely
Solution Approach 1:
The airbag transitions from a two-dimensional flat structure to a three-dimensional form through tubular chambers that inflate vertically and horizontally. The support struts extend in multiple directions (front-to-back, side-to-side, and vertically) to create a volumetric restraint structure that effectively limits leg movement in all relevant dimensions, preventing upward swinging while adapting to different seating positions.
Solution Approach 2:
The airbag is divided into multiple tubular inflatable chambers that function as separate support struts. Each chamber can be independently positioned and sized to provide targeted support at critical locations, allowing the structure to adapt to various occupant positions and vehicle configurations while maintaining overall protection effectiveness.
2Reliability
If the airbag uses a large volume to enclose space for comprehensive protection, then protection coverage is improved, but the amount of filling gas required increases significantly
Solution Approach 1:
The airbag utilizes thin-walled tubular chambers that can be positioned close to the occupant's legs without requiring excessive clearance. These flexible tubular structures provide effective restraint through their geometric configuration and strategic positioning rather than through large volume, minimizing the filling gas requirement while maintaining comprehensive protection coverage.
Solution Approach 2:
By transitioning to a three-dimensional tubular structure with support struts extending in multiple directions, the airbag achieves comprehensive spatial coverage and effective leg restraint without requiring large chamber volumes. The volumetric arrangement of thin-walled tubular chambers provides protection through geometric configuration rather than bulk volume, significantly reducing filling gas requirements.
3Stability of the object's composition
If the airbag requires support surfaces on vehicle components to maintain its shape, then structural stability is improved, but the device complexity and installation requirements increase
Solution Approach 1:
The airbag structure is self-stabilizing through its own internal geometry. The tubular chambers are arranged to form a three-dimensional framework where each chamber supports the others, creating inherent structural stability without requiring external support surfaces. The structure maintains its shape through the mutual support of its tubular elements and the pressure differential between internal and external environments.
Solution Approach 2:
The airbag is segmented into multiple tubular chambers that function as self-supporting struts. Each chamber's cylindrical geometry provides inherent structural stability, and the distributed arrangement of multiple chambers creates a mutually supportive framework that maintains overall structural integrity without requiring additional support surfaces or complex installation structures.
4Ease of manufacture
If the airbag uses traditional manufacturing methods with multiple parts, then assembly is straightforward, but material waste and manufacturing complexity increase
Solution Approach 1:
Multiple tubular chambers and support structures are merged into a single one-piece woven construction. This integrated manufacturing approach eliminates the need for separate components and assembly operations, significantly reducing material waste from cutting and joining operations while maintaining the structural integrity and functional performance of the multi-chamber design.
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 system ensures effective leg protection by stabilizing its shape with minimal gas volume, adapting to various seating positions, and cushioning legs without requiring additional vehicle support, while reducing material waste and manufacturing complexity.
Implementation Method 1
several tubular inflatable chambers (18) which are in fluid connection with one another and which, when inflated, are connected three-dimensionally to one another
Implementation Method 2
At least the portions of the airbag which include the inflatable chambers are one-piece woven
Data Source
AI summary
A vehicle occupant protection system comprises an airbag (112) for the protection of the legs of a vehicle occupant, wherein, prior to activation of the vehicle occupant protection system, the airbag (112) is arranged folded on a floor (30) of a vehicle in front of an associated vehicle seat and, in a situation of restraint, deploys from the bottom (30) in front of the vehicle seat. The airbag (112) comprises several tubular inflatable chambers (18) being in fluid connection which, when inflated, are connected three-dimensionally to one another, wherein several of the chambers (18) form support struts (124) of the airbag (112), while at least one of the chambers (18) forms a restraint chamber (22) in an upper area of the airbag (112) which is arranged directly in front of a shin area, a knee area or a pelvis area of the vehicle occupant. At least the portions of the airbag (112) which include the inflatable chambers (18) are one-piece woven.