Composite Fastener with Hard-Soft Sections for Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fastening devices for automotive components struggle to achieve both high retaining forces and maximum water tightness during assembly, while maintaining simplicity.
Innovation Solution
The use of a first fastening element with sections of harder and softer materials, where the softer section deforms to create a seal when a fastening screw is inserted, ensuring a tight fit and tolerance compensation, and the second fastening element is axially movable but torque-proof, allowing for non-rotational alignment and enhanced sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a fastening device with a cage part and female part is used to achieve high retaining forces, then the connection strength between components is improved, but the water tightness is compromised
Solution Approach 1:
The first fastening element is designed with differentiated material properties in different regions: a harder first section (material A) for structural strength and a softer second section (material B) for sealing. This local quality differentiation allows the same component to simultaneously provide both high retaining force through the harder section and effective water tightness through the softer section that deforms to seal against the second component's through opening.
Solution Approach 2:
The first fastening element is constructed as a composite structure with at least two different materials: material A (harder) for the first section and material B (softer) for the second section. This composite material approach enables the fastening element to exhibit both high mechanical strength for retaining forces and elastic deformation capability for sealing, thereby resolving the contradiction between strength and water tightness.
2Object-affected harmful factors
If a fastening device with extensive sealing measures is implemented to achieve maximum water tightness, then the sealing performance is improved, but the assembly complexity increases
Solution Approach 1:
The sealing function is merged into the first fastening element itself through the softer second section, eliminating the need for separate sealing components such as gaskets or sealing rings. The softer section of the fastening element directly seals against the second component's through opening, thereby achieving water tightness while maintaining simple assembly procedures.
Solution Approach 2:
The softer second section of the first fastening element automatically performs the sealing function through its own elastic deformation when the fastening screw is tightened. This self-service sealing mechanism eliminates the need for additional sealing components or complex sealing procedures, thereby achieving water tightness with simple assembly.
3Manufacturing precision
If a fastening device with rigid components is used to ensure precise alignment, then the positioning accuracy is improved, but the tolerance compensation capability is reduced
Solution Approach 1:
The first fastening element utilizes material parameter differentiation: the softer second section has lower stiffness to enable elastic deformation for tolerance compensation, while the harder first section maintains sufficient rigidity for precise alignment. This parameter change in material stiffness across different sections allows the device to simultaneously achieve precise alignment and tolerate manufacturing variations.
Solution Approach 2:
The first fastening element transitions from a completely rigid structure to a semi-flexible structure where the softer second section can elastically deform. This dynamic capability allows the fastening element to adapt to tolerance variations in the through openings of the first and second components while the harder first section maintains positioning accuracy, thereby achieving both precise alignment and tolerance compensation.
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 configuration achieves high retaining forces and maximum water tightness with simple assembly, while accommodating varying component tolerances and ensuring reliable fluid-tight sealing.
Implementation Method 1
the second fastening element upon screwing the fastening screw into its axial bore is pressed against the second section of the first fastening element and thereby deforms the same such that the second section abuts in a sealing manner on the surfaces delimiting the through opening of the second component
Data Source
AI summary
Device for fastening a first component (42) with a through opening (44) on a second component (40) with a through opening (18) being essentially rectangular in cross section, comprising a first fastening element (10) which comprises a radial flange (12) on one end and a shaft section (16) with rectangular cross section, which is insertable into the through opening of the second component and comprising a second fastening element which relative to the first fastening element is at least partly axially moveable, which second fastening element comprises an axial bore for receiving a fastening screw. The first fastening element comprises at least one first section (18) of a first, harder material and at least one second section (20) of a second, softer material, wherein the second fastening element upon screwing the fastening screw is pressed against the second section of the first fastening element and thereby deforming it in a sealing manner.