Frontal Airbag Guide Flap and Split Line Wrapper
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Solution Overview
Problem
Existing frontal airbag designs face challenges in protecting passengers positioned close to the airbag during deployment, particularly unbelted child seat occupants who are out of position, as per the upgraded Federal Motor Vehicle Safety Standard No. 208 requirements, which demands improved protection for such scenarios.
Innovation Solution
A frontal airbag assembly with a housing, inflatable airbag cushion, gas generator, and a wrapper with a split line and guide flap that tears during inflation, allowing the guide flap to guide the airbag cushion's expansion and protect the occupant by separating into front and rear portions, and featuring a cut-out to pass the occupant's nose and voids for visual inspection of proper installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the airbag assembly uses a traditional wrapper design without a split line, then the structure is simpler and easier to manufacture, but the airbag cannot properly deploy to protect out-of-position occupants and may cause abrasion injuries
Solution Approach 1:
The wrapper is divided into front and rear portions by introducing a split line that extends in the transverse direction. This segmentation allows the wrapper to separate during inflation, enabling the airbag to deploy effectively for out-of-position occupants while reducing abrasion risks. The split line is positioned to allow proper airbag expansion without compromising structural integrity where needed.
2Reliability
If the guide flap is permanently attached to the wrapper, then the structure is more stable, but the guide flap cannot release to allow proper airbag expansion and occupant protection
Solution Approach 1:
The guide flap is pre-positioned and attached to the wrapper in a controlled manner that allows it to perform its guiding function during initial inflation, then automatically release when needed. The attachment is designed to fail in a controlled way that ensures proper deployment sequence - the guide flap guides expansion first, then releases to allow full airbag deployment for occupant protection.
3Reliability
If the airbag assembly lacks a guide flap, then the structure is simpler, but the airbag cannot control its expansion direction to protect occupants and may cause injuries
Solution Approach 1:
The guide flap serves as an intermediary element between the airbag cushion and the wrapper. It controls the expansion direction of the airbag during deployment, guiding it to position correctly for occupant protection. The guide flap mediates the interaction between the inflating airbag and the wrapper constraints, ensuring safe and effective deployment while reducing injury risks.
4Reliability
If the inner end of the guide flap is permanently wedged between the wrapper and housing, then the guide flap maintains its position, but it cannot move outward to allow full airbag deployment
Solution Approach 1:
The guide flap transitions from a static wedged position to a dynamic movable position during deployment. Initially, the inner end is wedged between the wrapper and housing to maintain proper positioning and guide expansion. During inflation, the force overcomes this wedging, allowing the guide flap to move outward and release, enabling full airbag deployment while maintaining control throughout the process.
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 assembly effectively deploys to protect both the head and torso of out-of-position occupants by guiding the airbag cushion's expansion, reducing the risk of abrasion and ensuring proper installation through visual inspection, thus meeting the enhanced safety standards for Positions 1 and 2.
Implementation Method 1
a gas generator attached to the housing near the bottom wall and having a gas outlet in fluid connection with the gas inlet of the airbag cushion
Data Source
AI summary
A frontal airbag assembly has a housing defining an airbag space. An inflatable compacted airbag cushion is arranged in the airbag space and has a gas inlet connected to a gas generator. A wrapper having a front end attached outside of the housing to the front wall or the bottom wall of the housing and a rear end attached to the rear wall or the bottom wall of the housing. A guide flap extends between the wrapper and the airbag cushion and has an outer end attached to the wrapper between the front end and a split line of the wrapper, a first inward fold between the split line and the rear wall, and an inner end arranged between the wrapper and an upper portion of the front wall. The guide flap is released when the split line has separated the wrapper into a front portion and a rear portion.