Knee Airbag Three-Part L-Shaped Deployment
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Solution Overview
Problem
Existing knee airbags tend to deploy in the longitudinal direction of the vehicle, failing to accurately abut against the bottom and front walls of the instrument panel, which limits their effectiveness in preventing lower limb contact during frontal collisions.
Innovation Solution
A knee airbag design comprising three parts with two seams, where one seam rests against the lower edge of the instrument panel and the other connects upper parts, forming an L-shaped profile and mushroom-like shape upon deployment, ensuring accurate contact with the panel's surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the knee airbag uses a traditional single-piece or two-piece bag design, then the manufacturing process is simpler, but the airbag deploys in the longitudinal direction (X direction) between the driver's or passenger's feet instead of accurately abutting against the bottom and front walls of the instrument panel
Solution Approach 1:
The airbag sack is divided into three distinct parts: a first part, a second part, and a third part. The first and second parts are connected by a first seam to form side A, while the third part forms side B. This segmentation allows the airbag to deploy in a controlled L-shaped profile with side A abutting against the bottom and front walls of the instrument panel, achieving accurate deployment positioning while maintaining manageable manufacturing complexity through modular construction.
Solution Approach 2:
The airbag employs asymmetric design where side A (formed by first and second parts) and side B (formed by third part) have different configurations and functions. Side A is designed to abut against the instrument panel walls with specific seam positioning, while side B faces the vehicle interior. This asymmetry enables precise deployment geometry where the first seam rests against the lower edge of the instrument panel, ensuring the airbag contacts the correct surfaces during deployment.
2Reliability
If the knee airbag is designed to deploy accurately against the instrument panel walls, then protection effectiveness is improved, but the bag requires more complex seam and part configuration
Solution Approach 1:
The airbag is segmented into three parts connected by two seams, where the first seam connects the first and second parts to form side A, and the second seam connects the second and third parts. This segmentation creates an L-shaped deployment profile that ensures side A accurately abuts against the bottom and front walls of the instrument panel, maximizing protection effectiveness by positioning the airbag cushion exactly where needed to prevent lower limb contact with hazardous elements.
Solution Approach 2:
Different parts of the airbag sack are assigned different functions and configurations. The first and second parts (forming side A) are specifically designed and positioned to contact the instrument panel walls during deployment, while the third part (forming side B) faces the vehicle interior. The first seam is strategically positioned to rest against the lower edge of the instrument panel, creating a localized high-quality contact zone that maximizes protection where it is most needed.
Data Source
AI summary
The knee airbag consists of a fabric bag, a gas generator, and a control unit, and in its folded state is located in the lower area of the vehicle's instrument panel. The bag (10) is formed by three parts (1, 2, 3) and has two seams (4, 5), with parts (1) and (2) of the bag (10) forming side A and part (3) of the bag (10) forming side B. When the airbag is activated, i.e., when the bag (10) is deployed, it has an L-shaped profile and rests with side A against the lower (21) and front (22) wall of the instrument panel (20), while side B is oriented towards the vehicle interior (60).