Knee Airbag Module Covering Element Pivoting Design
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Solution Overview
Problem
Current airbag modules, particularly knee airbag modules, face challenges in minimizing mass while ensuring rapid deployment and effective unfolding, due to the limited time between gas generator activation and airbag deployment, especially when there is a small distance between the occupant's knee/shin area and the dashboard.
Innovation Solution
The airbag module employs a covering element made of textile fabric, which is flexible and strong, allowing for quick airbag deployment by pivoting against the dashboard, reducing the force required to open the outlet and enabling a lighter gas generator and housing design, with a geometry that applies force diagonally to the outlet opening, facilitating rapid airbag escape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the airbag module uses a rigid housing with a fully circumferential wall and an injection molded covering element, then the structural strength and sealing are improved, but the mass increases and the deployment speed decreases
Solution Approach 1:
The covering element is made from a flexible textile material instead of rigid injection molded plastic, allowing it to deform and pivot during deployment. This reduces the mass of the covering element while maintaining its function of sealing the outlet opening during storage and allowing rapid deployment when activated.
Solution Approach 2:
The covering element is designed to pivot dynamically during deployment rather than being fixed rigidly. The textile material allows the covering element to change its configuration from a sealed state during storage to an open state during deployment, enabling faster airbag deployment while reducing overall mass.
2Stability of the object's composition
If the airbag module uses a rigid housing with a fully circumferential wall, then the outlet opening sealing is improved, but the deployment speed decreases due to the time required to free the outlet opening
Solution Approach 1:
The flexible textile covering element can rapidly deform and pivot away from the outlet opening when the airbag inflates, unlike rigid covering elements that require more time and force to move. This maintains sealing during storage but enables rapid deployment.
Solution Approach 2:
The covering element is designed to be separable from the housing structure through a pivoting mechanism rather than being permanently fixed. This allows the covering element to be extracted or moved away from the outlet opening quickly during deployment while maintaining structural integrity during storage.
3Manufacturing precision
If the covering element is designed as an injection molded part, then the manufacturing precision and geometric complexity are improved, but the mass increases and flexibility decreases
Solution Approach 1:
The covering element is made from flexible textile material that can be sewn or attached to the housing, replacing rigid injection molded parts. This reduces mass while providing sufficient precision for the covering function through textile manufacturing techniques.
Solution Approach 2:
The textile covering element can be produced more economically and with less material than rigid injection molded parts, reducing mass while maintaining adequate precision for its temporary function during deployment.
4Duration of action of moving object
If the covering element is made from textile fabric material, then the flexibility and mass are reduced, but the manufacturing complexity increases
Solution Approach 1:
The textile covering element provides the required flexibility for rapid deployment and pivoting motion. The manufacturing complexity is managed through standardized textile cutting and attachment methods that are well-established in the industry.
Data Source
AI summary
A knee airbag module for a motor vehicle. The airbag module has a housing which is preferably composed of plastic and has a housing base (12) and a wall extending from the housing base (12), forming an outlet opening. A receptacle is provided in a first wall section. An airbag is folded into the housing, an air generator (30) which has outflow openings located within the airbag, and a covering element which closes the outlet opening. This covering element has a main section (54) which lies substantially in one plane, at least one first end section (52) accommodated in the at least one receptacle, and a second end section (56) situated opposite the first end section (52), extends out of the plane of the main section (54) and is connected to the housing (10). The covering element (50) is produced from a blank.