Knee Air Bag Upward Deployment Tether
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Solution Overview
Problem
Conventional knee air bags interfere with roof air bags during deployment, leading to secondary injuries such as neck twisting due to excessive protrusion, as they are not designed to consider the interaction with other air bags, resulting in inadequate protection for both the upper body and knees.
Innovation Solution
A knee air bag design featuring an inflator, diffuser, and cushion with an external tether that guides the cushion to deploy upwards, reducing interference with the roof air bag by securing the tether to the cushion's upper and lower ends, and incorporating a diffuser with vent holes for even gas distribution and tethers to control inflation, ensuring rapid and effective deployment without colliding with the roof air bag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the knee air bag is deployed using conventional design, then the knee protection function is achieved, but the roof air bag is excessively pushed towards the passenger causing secondary injuries
Solution Approach 1:
The external tether is pre-installed on the cushion before deployment, positioned to automatically engage and restrain the cushion's upward movement. This preliminary preparation of the restraint mechanism prevents the harmful interaction with the roof air bag before it occurs, rather than reacting after the problem arises.
Solution Approach 2:
The external tether acts as an intermediary element between the knee air bag cushion and the roof air bag. It mediates the interaction by controlling the cushion's deployment path and limiting its upward movement, thereby preventing direct harmful contact between the two air bags while maintaining protective function.
2Speed
If the cushion is deployed rapidly to protect the knee, then the protection response time is improved, but the interference with the roof air bag increases causing excessive protrusion
Solution Approach 1:
The external tether is pre-configured with the cushion at the optimal restraint position before deployment. When rapid deployment occurs, the tether immediately engages to counteract excessive upward movement, allowing fast response while preventing harmful over-deployment that would cause secondary injuries.
Solution Approach 2:
The external tether provides dynamic control during deployment, allowing the cushion to expand rapidly for knee protection while simultaneously restraining upward movement. The tether's tension dynamically adjusts during the deployment process to permit necessary expansion while preventing excessive protrusion.
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 design prevents secondary injuries by ensuring the knee air bag deploys upwards along the seatback, minimizing interference with the roof air bag, and allows for rapid and effective protection of the passenger's knees, reducing the risk of neck or head injuries while maintaining a compact shape for efficient deployment.
Implementation Method 1
having an inflator, a diffuser and a cushion to protect a passenger's knee when the cushion is deployed
Implementation Method 2
an external tether which is provided on an upper portion of the inflator connector and secured at lower and upper ends thereof to the back of the cushion, thus guiding the cushion so that the cushion is deployed upwards
Data Source
AI summary
A knee air bag for a vehicle has an inflator, a diffuser and a cushion to protect a passenger's knee when the cushion is deployed. The knee air bag also includes an inflator connector which is provided on a back of the cushion, and an external tether which is provided on an upper portion of the inflator connector and secured at lower and upper ends thereof to the back of the cushion, thus guiding the cushion so that the cushion is deployed upwards. The knee air bag makes the cushion come into close contact with a seatback of the vehicle when the knee air bag is deployed, thus reducing interference with a roof air bag located at an upper position, therefore preventing a passenger's head or neck from suffering secondary injuries.