Variable Extension Hinge for Air Bag Chute Door
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Solution Overview
Problem
The existing air bag deployment door designs in automotive vehicles often intersect with the windshield during deployment, leading to potential damage and increased costs due to the need for tethers to prevent this, while also requiring a large door size to accommodate larger and more powerful air bags, which complicates styling and aerodynamics.
Innovation Solution
The air bag chute assembly features a tubular chute with a door flap attached via a hinge with S-shaped extendable straps of varying lengths, restricting rotation at one end to prevent over-rotation and minimize the sweep zone, eliminating the need for additional tethers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the air bag door is placed near the top surface of the instrument panel to provide optimum passenger protection, then the air bag deployment effectiveness is improved, but the door is more likely to intersect with and damage the windshield during deployment
Solution Approach 1:
The hinge straps are designed with S-shaped geometry that allows dynamic extension and restriction during door rotation. The variable lengths enable the hinge to adapt its rotational characteristics during deployment, restricting the door sweep zone to prevent windshield contact while maintaining deployment effectiveness.
Solution Approach 2:
Different hinge straps have different lengths to create localized rotational restrictions at specific points along the door edge. This allows precise control over which portions of the door sweep zone are restricted, enabling the door to open sufficiently for bag deployment while preventing contact with the windshield in critical areas.
2Area of moving object
If the air bag door size is increased to accommodate larger and more powerful air bags, then the air bag capacity is improved, but the door swing area is more likely to intersect with the windshield
Solution Approach 1:
The hinge assembly uses straps of varying lengths to create localized rotational restrictions at specific points along the door edge. This allows the door to achieve sufficient overall opening size for large air bags while restricting the sweep zone in areas that would intersect with the windshield.
Solution Approach 2:
The hinge is divided into multiple separate straps rather than a single continuous hinge. This segmentation allows independent control of rotational characteristics at different locations along the door, enabling precise management of the door sweep zone to accommodate large bags without windshield contact.
3Manufacturing precision
If a tether is added to prevent the door from swinging beyond the required opening size, then the door sweep zone control is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The door sweep zone control function is extracted from a separate tether component and integrated directly into the hinge structure through variable length straps. This eliminates the need for additional tethers while maintaining precise control over the door rotation and sweep zone.
Solution Approach 2:
The hinge and door sweep zone control functions are merged into a single integrated hinge assembly with variable length straps. This combines what would traditionally be separate components (hinge and tether) into one unified structure, reducing overall device complexity and manufacturing steps.
4Productivity
If the instrument panel depth is shortened to improve aerodynamics and styling, then the aerodynamic performance is improved, but the air bag door is more likely to contact the windshield during deployment
Solution Approach 1:
The S-shaped hinge straps provide dynamic extension and restriction during door rotation, adapting to the reduced instrument panel depth configuration. This allows the door to deploy effectively in the shortened space while the variable strap lengths restrict the sweep zone to prevent windshield contact.
Solution Approach 2:
The hinge strap lengths are specifically designed as variable parameters to compensate for the reduced instrument panel depth. By adjusting the strap lengths, the system maintains appropriate door sweep zone control despite the shorter available deployment space, preventing windshield contact while preserving aerodynamic benefits.
Data Source
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AI summary
An air bag chute assembly attaches an air bag module to an automotive instrument panel. An outer collar attaches the assembly to the instrument panel. A tubular chute extends interiorly from the collar to a lower end defining a deployment path for the air bag. A door flap is disposed in an upper end of the chute rotatable from the collar to emerge from the instrument panel. A hinge attaching the door flap to the collar comprises a plurality of S-shaped extendable hinge straps laterally spaced along one edge of the door flap. A first hinge strap proximate one lateral end of the hinge has a first length shorter than a second length of a second hinge strap proximate an opposite lateral end of the hinge, thereby restricting rotation of the door flap at the one lateral end in order to avoid contacting a windshield during deployment.