Steering Wheel Airbag Module Retaining Means
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Solution Overview
Problem
Existing steering wheel units face challenges in achieving precise positioning of the airbag module while maintaining high operational reliability, often requiring robust positioning means that increase production time and costs due to tolerance issues and the need for strengthening elements.
Innovation Solution
Incorporating additional retaining means between the airbag module and the steering wheel that are inactive under normal conditions, allowing for less stringent design requirements for positioning means, which are only activated during high forces from the gas generator, such as retaining hooks and omega springs, to ensure secure attachment without compromising precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If robust positioning means are used to ensure airbag module remains connected during gas generator ignition, then operational reliability is improved, but manufacturing precision and production time deteriorate due to tolerance chains and need for strengthening elements
Solution Approach 1:
The connection system is divided into two separate functional components: positioning means (axial positioning hooks and steps) for precise location during normal operation, and retaining means (retaining hooks and omega springs) for securing during high-force events. This segmentation allows each component to be optimized for its specific function without compromising the other.
Solution Approach 2:
The retaining means are designed to be dynamically engaged only when necessary - the omega springs remain inactive during normal operation but automatically engage to provide retaining force when high forces occur during gas generator ignition. This dynamic activation eliminates the need for continuously robust positioning structures.
2Reliability
If robust positioning means with strengthening elements are used, then operational reliability is improved, but device complexity and production costs increase
Solution Approach 1:
The connection system is divided into two separate functional components: positioning means (axial positioning hooks and steps) for precise location during normal operation, and retaining means (retaining hooks and omega springs) for securing during high-force events. This segmentation allows each component to be optimized for its specific function without compromising the other.
Solution Approach 2:
The omega springs are designed as simple, inexpensive retaining elements that can be easily manufactured and replaced if needed. Their simple geometry and use of conventional spring material make them cost-effective compared to continuously robust positioning structures.
3Reliability
If positioning means are designed to be robust for high forces, then operational reliability is improved, but positioning precision deteriorates due to tolerance chains
Solution Approach 1:
The connection system is divided into two separate functional components: positioning means (axial positioning hooks and steps) for precise location during normal operation, and retaining means (retaining hooks and omega springs) for securing during high-force events. This segmentation allows each component to be optimized for its specific function without compromising the other.
Solution Approach 2:
The retaining means are designed to be dynamically engaged only when necessary - the omega springs remain inactive during normal operation but automatically engage to provide retaining force when high forces occur during gas generator ignition. This dynamic activation eliminates the need for continuously robust positioning structures.
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
This solution enables improved mounting and removal capabilities, reduces manufacturing complexity, and maintains precise positioning without the need for excessive robustness in positioning components, thus enhancing operational reliability and aesthetic appeal.
Implementation Method 1
compression springs are provided between the housing floor and the steering wheel, which push the housing away in axial direction
Data Source
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AI summary
A steering wheel unit for a motor vehicle is described. This steering wheel unit has a steering wheel and an airbag module (30) located in the hub area of the steering wheel. This airbag module exhibits a housing (32), an airbag (52) folded into the housing, and a gas generator (54). The airbag module can be pushed down against the force of at least one spring element, whereby positioning means are present which define the position of the airbag module in relation to the steering wheel. In order to achieve a high degree of operational reliability and a very exact positioning of the airbag module in the steering wheel, at least one retaining means (28;38,68) is present which acts between the airbag module and the steering wheel (28;38,68). This retaining means is ineffective in the absence of outer forces and when the airbag module (30) is pressed down.