Sealed Screw Assembly Using Plastic Deformation
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Solution Overview
Problem
Existing methods for sealing between a screw and a bore require additional pieces or specific surface finishes, are costly, and do not effectively handle high mechanical, vibratory, and thermal stresses, especially between metal surfaces with non-smooth finishes.
Innovation Solution
A method where the screw is engaged in an enlarged bore, and the screw head presses into the support material, creating a sealed fit without additional pieces, using standard screws and supports made from materials with differing mechanical strengths, such as aluminum and steel, to form a rim and frustoconical surfaces for enhanced sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional sealing pieces or smooth surface treatments are used, then sealing reliability is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The screw head itself performs the sealing function by deforming the support material under its own tightening force, eliminating the need for separate sealing components. The support material's plasticity allows it to deform and conform to the screw head surface, creating a seal automatically during the fastening process.
Solution Approach 2:
The support material's mechanical properties are utilized - specifically its plasticity and ductility - to allow permanent deformation under the screw head. By controlling the deformation parameter through proper screw tightening force, a reliable seal is achieved without additional components.
2Reliability
If additional sealing pieces or smooth surface finishes are used, then sealing reliability is improved, but manufacturing cost increases
Solution Approach 1:
The support material serves its dual function of structural support and sealing. No additional sealing components need to be manufactured, procured, or installed, significantly reducing manufacturing cost while maintaining sealing reliability.
Solution Approach 2:
The sealing function is extracted from being a separate component requirement and integrated into the fastening process itself. The sealing action is taken out from being a post-assembly step and becomes an inherent part of the screw tightening operation.
3Ease of manufacture
If the support material is deformed to create a seal, then sealing is achieved without additional pieces, but the support's mechanical strength is reduced
Solution Approach 1:
The deformation is localized to a small area directly under the screw head contact zone. The majority of the support structure retains its full mechanical strength and structural integrity, while only the local sealing region undergoes controlled deformation.
Solution Approach 2:
Only partial deformation of the support material is required - just enough to create the sealing contact under the screw head. The deformation is controlled to be sufficient for sealing but not excessive to compromise overall structural strength.
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 method achieves a simple, economical, and effective seal between metal pieces under high stresses without requiring smooth surfaces or additional sealing components, ensuring impermeability and secure assembly.
Implementation Method 1
the pressure exerted by the head causes a sealed fitting of the opening on part of the surface under the head of the screw by pushing back part of the material belonging to the support
Data Source
AI summary
A method for producing a sealing arrangement between an opening of the support, bore and a screw which comprises a head connected to a body and is provided with a threaded section for interacting with the hole of a part to be assembled with a support whose mechanical strength is lower than that of the screw. The invention is characterized in that, starting from an enlarged opening, the inventive method consists in engaging the screw into the bore in such a way that the head thereof is brought into contact with the opening, in screwing the screw into the hole of the part to be assembled in such a way that a pressure applied by the head sealingly presses the opening against the part of the under-head surface of the screw by removing a part of material of the support.