Doghouse Blind Fastener Assembly for Close Panel Joining
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Solution Overview
Problem
Existing fastening techniques for closely positioned automotive panels face issues such as corrosion, noise (BSR), and manufacturing complexity, particularly with metal fasteners, while plastic fasteners may not provide a secure and reliable blind connection.
Innovation Solution
A fastening system utilizing a pass-through doghouse-based configuration with a fastener and seal assembly, where the fastener has a head assembly that engages a doghouse structure on one panel and passes through an opening on another, minimizing assembled distance and protrusion, and incorporating a seal assembly for enhanced security and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal fasteners are used to make blind connections between panels, then secure fastening is achieved, but the abrasive nature wears through paint or anticorrosive coatings promoting corrosion
Solution Approach 1:
The patent employs a sacrificial zinc coating on the metal fastener that corrodes preferentially to protect the underlying steel and the vehicle panel. The zinc layer acts as a disposable protective barrier that sacrifices itself through controlled corrosion to prevent harmful corrosion of the main structural components.
Solution Approach 2:
The fastener utilizes a composite structure with a steel core providing structural strength and a zinc coating providing corrosion protection. This composite material approach combines the advantages of both materials - the high strength of steel with the corrosion resistance of zinc - to achieve secure fastening without the harmful corrosion effects of pure metal fasteners.
2Strength
If metal fasteners are used to make blind connections between panels, then secure fastening is achieved, but the fasteners tend to buzz, squeak, and rattle (BSR)
Solution Approach 1:
The fastener employs a composite construction with a metal core for structural integrity and a plastic or elastomeric coating that dampens vibrations. This composite material approach reduces BSR by combining the strength of metal with the noise-dampening properties of polymer materials, eliminating the harmful buzzing, squeaking, and rattling effects.
Solution Approach 2:
The patent modifies the physical parameters of the fastener by changing the material composition and damping characteristics. By adjusting the material properties - specifically incorporating vibration-dampening materials or modifying the surface treatment - the fastener's ability to reduce noise is improved while maintaining its fastening strength.
3Object-affected harmful factors
If plastic fasteners are used to replace metal fasteners to mitigate abrasion and avoid BSR, then corrosion and noise are reduced, but the distance between panels increases and moderately high insertion forces are required
Solution Approach 1:
The fastener uses a composite structure with a metal core providing structural rigidity to maintain proper panel spacing, and a plastic or elastomeric outer layer providing corrosion resistance and vibration damping. This composite approach allows the fastener to reduce harmful corrosion and noise effects while the metal core ensures the panel distance is maintained at appropriate levels.
Solution Approach 2:
The patent optimizes the material properties and geometric parameters of the fastener to achieve the desired balance. By carefully selecting material compositions and fastener dimensions, the design achieves reduced corrosion and noise while maintaining appropriate panel spacing and reducing insertion forces through optimized material hardness and elasticity parameters.
4Object-affected harmful factors
If combination metal and plastic fasteners are used to mitigate abrasion and avoid BSR, then corrosion and noise are reduced, but the fasteners are larger and more difficult to manufacture
Solution Approach 1:
The patent integrates the metal core and plastic coating into a single unified fastener component through processes such as plating, coating, or overmolding. This merging of materials into one integrated part achieves the benefits of both materials - corrosion resistance and noise reduction - while simplifying manufacturing by eliminating the need to assemble separate metal and plastic components, thereby reducing device complexity.
Data Source
AI summary
Disclosed are Systems and methods for coupling a first panel to a second panel using a fastening system. The fastening system includes a fastener, a doghouse structure, and a seal assembly. The fastener includes a head assembly coupled to a collar using the doghouse structure. The head assembly engages the doghouse structure positioned on the first panel and the collar passes through an opening in the second panel to retain the second panel relative to the first panel. The seal assembly includes a seal and a seal carrier that is coupled to the fastener via a frangible connection.