Knee Airbag Traction Element Curved Shape Design
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Solution Overview
Problem
Existing knee airbag designs face challenges in achieving a curved or bent shape during expansion while being easy to produce and assemble, with previous methods requiring complex sewing processes or force transmission components.
Innovation Solution
An airbag with a traction element attached to its side wall, where the traction element's length is shorter than the section it spans, forcing the airbag into a curved shape upon expansion, and optionally configured as a constricted fill channel to reduce gas volume or filling time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the side wall is shortened to achieve curved cross section, then the desired banana-shaped cross section is obtained, but relatively precise sewing processes that are difficult to automate are required
Solution Approach 1:
The traction element is attached to the side wall in advance during manufacturing, creating a pre-configured tensioning system that will automatically form the curved cross section when the airbag inflates, eliminating the need for complex post-manufacturing adjustments or precise sewing processes
2Shape
If a traction element in the form of a strap is sewn on the side wall to achieve curved shape, then the desired shape is obtained, but the assembly in the motor vehicle becomes relatively complicated requiring connection to another vehicle part
Solution Approach 1:
The force transmission function is extracted from the airbag system itself by incorporating the traction element directly into the airbag envelope structure, eliminating the need for separate external connection components and simplifying the overall assembly process
Solution Approach 2:
The traction element is merged with the airbag envelope as an integrated component, combining the shaping function and the force transmission function into a single unified structure that requires no additional external connections
Data Source
AI summary
An airbag has an airbag envelope (10) having two side walls (12, 14) enclosing a gas chamber. The first side wall (12) constitutes herein the impact surface and the second side wall (14) constitutes the support surface. A traction element (20) furthermore extends from a first end to a second end, whose first end is connected to the outer side of the second side wall (14) in order to force the inflated airbag to assume a curved shape. In order to achieve an easy production and assembly, the second end of the traction element (20) is also connected to the outer side of the second side wall (14), wherein the operating length of the traction element (20) is smaller than the length of the section of the second side wall (14) that is spanned thereby.