Pedestrian Protection Airbag Partitioning Tether Design
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Solution Overview
Problem
Conventional pedestrian protection airbag devices struggle to deploy quickly and effectively over the upper surfaces of front pillars due to oscillation issues during deployment.
Innovation Solution
The airbag device features a partitioning tether that inflates the primary region first, with gas flow paths narrowing to the supply ports, allowing for rapid inflation and deployment of the vertical inflatable portions over the pillars without oscillation, and includes thickness regulating sections to ensure uniform deployment and prevent the airbag from getting hung up between the hood and cowl.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the airbag is deployed using conventional design without partitioning tether, then the structure is simpler, but the vertical inflatable portions oscillate and cannot be deployed quickly over the front pillars
Solution Approach 1:
The airbag is divided into multiple inflatable portions (horizontal inflatable portion and vertical inflatable portions) separated by partitioning tethers. This segmentation allows different regions to inflate at controlled rates, with the horizontal portion inflating first to guide gas flow, preventing oscillation of the vertical portions while achieving rapid deployment.
2Speed
If the airbag inflates uniformly throughout, then the inflation process is simpler, but the vertical inflatable portions cannot be deployed quickly and adequately over the front pillars
Solution Approach 1:
The horizontal inflatable portion inflates first as a preliminary action before the vertical inflatable portions. This preliminary inflation establishes proper gas flow paths and positioning, ensuring that when the vertical portions inflate subsequently, they deploy quickly and adequately over the front pillars without oscillation.
Solution Approach 2:
Different regions of the airbag are given different inflation characteristics. The horizontal inflatable portion has different structural properties than the vertical inflatable portions, allowing localized control of inflation timing and rate. This local quality differentiation enables the horizontal portion to inflate first while the vertical portions follow, achieving rapid and controlled deployment.
3Ease of operation
If the airbag is designed without thickness regulation, then the manufacturing is simpler, but the airbag may get hung up between the hood and cowl during deployment
Solution Approach 1:
Thickness regulating sections are added at specific locations where the airbag may contact the hood or cowl during deployment. These localized structural features control the thickness of the airbag at critical points, preventing it from getting hung up while maintaining simplicity in other regions of the airbag structure.
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 deploys quickly and adequately over the upper surfaces of the front pillars, ensuring effective protection by preventing oscillation and ensuring proper inflation without obstruction.
Implementation Method 1
the inflation gas having flown into the airbag via the inlet port will firstly flow into the primary inflatable region disposed in front of the partitioning tether of the horizontal inflatable portion, and then flow towards the left and right along the partitioning tether. Subsequently, the gas flows into the secondary inflatable portion via the supply ports
Data Source
AI summary
An airbag (60) of a pedestrian protection airbag device (M) includes a horizontal inflatable portion (66) that covers a cowl (7) disposed at the rear of a vehicle hood (10) and a pair of vertical inflatable portions (72) that cover left and right front pillars (5). The horizontal inflatable portion (66) includes an in-hood inflatable portion (67) that is deployable beneath the rear end (10c) of the hood (10) and an out-of-hood inflatable portion (70) that is deployable in such a manner as to protrude out of the hood and is in gas communication with the vertical inflatable portions (72) at vicinities of its left and right ends. The airbag further includes a partitioning tether (74) that partitions an inflatable region of the airbag as fully inflated ranging from the out-of-hood inflatable portion to the left and right vertical inflatable portions into a primary inflatable region (81) and a secondary inflatable region (82) which is shaped along the rear edge (60b) of the airbag. Supply ports (80) via which the secondary inflatable region admits an inflation gas from the primary inflatable region are disposed only at vicinities of left and right ends (74a, 74b) of the partitioning tether.