Frontal Airbag Tether Reduces Neck Rotational Forces
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Solution Overview
Problem
Frontal airbags are inadequate in protecting passengers during laterally offset frontal crashes, as they can cause rapid head rotation and high forces on the neck due to frictional forces and linear deceleration.
Innovation Solution
A frontal airbag module with a first tether connected to the outer skin along two transverse connections, creating a 'soft cell' by reducing tension in the intermediate section, allowing head movement and reducing rotational forces on the neck, and enabling the airbag to rotate horizontally to follow the passenger's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the airbag is designed to provide strong deceleration force to stop the head, then the head is protected from forward impact, but rapid head rotation and high forces on the neck occur due to frictional forces
Solution Approach 1:
The airbag is divided into different functional zones with distinct mechanical properties. The impact area is segmented into a first section with higher tension and a second section (intermediate section) with reduced tension, creating a soft cell that allows controlled head movement and reduces rotational forces while maintaining deceleration protection.
Solution Approach 2:
Different sections of the airbag are given different local qualities in terms of tension and stiffness. The first section has higher tension to provide strong deceleration, while the second section has reduced tension to allow head movement and reduce rotational forces, creating a gradient of mechanical properties across the airbag surface.
2Stability of the object's composition
If the airbag impact area is made rigid to provide stable protection, then the airbag maintains its shape and protective function, but it cannot follow the passenger's movement during offset crashes
Solution Approach 1:
The airbag transitions from a static rigid structure to a dynamic system with variable tension zones. The soft cell in the second section allows the airbag to dynamically adapt its shape and follow passenger movement during offset crashes, while the first section maintains overall structural stability.
Solution Approach 2:
The airbag is segmented into zones with different degrees of flexibility. The first section maintains rigidity for stable protection, while the second section with reduced tension provides adaptability to follow passenger movement, allowing the airbag to respond to different crash scenarios.
3Device complexity
If the airbag uses uniform tension across the impact area, then the manufacturing and design are simplified, but it cannot provide optimized protection for both pure frontal and offset crashes
Solution Approach 1:
Instead of uniform tension, the airbag implements local quality variations with different tension levels in different sections. This creates optimized protection for both pure frontal crashes (first section) and offset crashes (second section), improving reliability without excessive complexity through the tether system.
Solution Approach 2:
The tension parameter is changed across different sections of the airbag. The first section has higher tension for frontal crash protection, while the second section has reduced tension for offset crash protection, allowing the airbag to handle multiple crash scenarios effectively.
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 solution provides improved protection by reducing deceleration forces on the head and neck during laterally offset crashes, minimizing the risk of serious injuries by allowing head movement and distributing forces more evenly.
Implementation Method 1
The first tether is under tension when the airbag is fully deployed because the first tether is (in the first direction) shorter than the intermediate section and/or because of the presence of a second tether connecting the first tether to another part of the airbag or to the housing of the airbag module. Due to the tension in the first tether, the tension in the section of the frontal airbag which is spanned over by the first tether (the intermediate section) is reduced
Implementation Method 2
when the head of the passenger hits the impact area of the frontal airbag the head is held by the same because of frictional forces, but the body of the passenger continues to move towards the inside of the car
Data Source
AI summary
A frontal airbag (10) having an outer skin (12) enclosing a gas space (G). The outer skin (12) forming an impact area (14) in front a vehicle occupant (P) and extends horizontally in a first direction (Y) and in a second perpendicular direction (Z′) when the airbag (10) is fully deployed. A first tether (20) extends in the first direction (Y) from a first end (21) connected to the impact area (14) at a first connection (25) to a second end (22) connected to the impact area (14) at a second connection (26). The first connection (25) extending in the second direction (Z′) from a lower end to an upper end and the second connection (24) extending in the second direction (Z′) from a lower end to an upper end, such that an intermediate impact area section (14c) is spanned by the first tether (20). The first tether (20) is under tension when the outer skin (12) is fully deployed such that the tension in the intermediate section (14c) of the impact area (14) is reduced relative to impact area sections (14a, 14b) next to the intermediate section (14c).