Airbag Thin Regions for Knee Protection
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Solution Overview
Problem
Existing airbag designs for knee protection struggle to deploy smoothly along the curved rear face of vehicle body structures, particularly where the middle region protrudes rearward, leading to inadequate protection and deployment efficiency.
Innovation Solution
The airbag apparatus features a flexible airbag with thin regions that remain thin upon inflation, connected by an outer connecting element with joints arranged away from each other in the up and down direction, allowing the airbag to bend and deploy in a bowing fashion, and includes a cushioning region and tethers to ensure effective knee protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the airbag is designed with a uniform thickness structure, then the cushioning region provides adequate protection, but the airbag cannot deploy smoothly along the curved rear face of the vehicle body structure
Solution Approach 1:
The airbag is designed with non-uniform thickness distribution: thin regions (where walls are approximated) enable bending and deployment along curved surfaces, while the cushioning region maintains sufficient thickness for protection. This local differentiation allows the airbag to conform to the curved rear face of the vehicle body structure while providing reliable knee protection.
2Shape
If the vehicle body side wall is shortened in up and down direction, then the airbag can deploy along curved surfaces, but the deployment smoothness is insufficient
Solution Approach 1:
The airbag is divided into multiple functional regions: thin regions for bending, cushioning region for protection, and an outer connecting element with two joints arranged away from each other in the up and down direction. This segmentation allows different parts to perform specialized functions, enabling smooth deployment along curved surfaces while maintaining deployment speed.
Solution Approach 2:
The airbag design incorporates curved deployment characteristics through the outer connecting element that reduces the substantial length of the vehicle body side wall. The two joints arranged away from each other create a bowing fashion deployment pattern that conforms to the curved rear face of the vehicle body structure, improving deployment smoothness.
3Ease of operation
If thin regions are formed by approximating walls, then the airbag can bend upon deployment, but stress concentration may occur at these thin regions
Solution Approach 1:
The airbag structure differentiates between thin regions (for flexibility and bending) and the cushioning region (for strength and protection). The thin regions are strategically located where bending is needed, while the cushioning region maintains sufficient wall separation and thickness to resist stress and provide reliable protection during impact.
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 configuration enables the airbag to deploy smoothly and quickly along the curved rear face of the vehicle body structure, providing steady protection to the occupant's knees by maintaining a thick and wide cushioning region while preventing stress concentration at the thin regions.
Implementation Method 1
an inflator for supplying the airbag with an inflation gas
Data Source
AI summary
An airbag apparatus mountable in front of a seat of a vehicle and including an airbag is disclosed. The airbag is deployable between a member of a vehicle body structure and knees of a vehicle occupant. The airbag includes a bag body formed by connecting peripheral edges of a vehicle body side wall and an occupant side wall, an outer connecting element that is located on an outer face of the vehicle body side wall and connected to the vehicle body side wall by two joints arranged away from each other in an up and down direction at deployment for reducing a length in an up and down direction of the vehicle body side wall, and a plurality of thin regions that are arranged between the two joints of the outer connecting element to the vehicle body side wall on the bag body. The thin regions are arranged generally along a left and right direction in a mutually separate fashion and help bend the airbag at deployment.