Press-In Cap Nut Assembly for Media-Tight Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing press-in connections, particularly press-in nuts, face challenges in achieving media-tightness without damaging anti-twist elements during the production of cap nuts, which requires complex and costly processes such as welding or high-force press-fitting, leading to potential mechanical property deterioration and increased production costs.
Innovation Solution
A pre-assembled press-in nut design where the cap is initially partially bent to form retaining lugs, allowing for low-force captive fixation, followed by a second process step where the ring collar is completely bent to form a media-tight connection, separating the formation of a captive pre-fixation from the media-tight sealing to avoid damaging anti-twist elements and reduce production complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If welding is used to join cap to nut body, then media-tight connection is achieved, but local heat treatment changes mechanical properties and requires complex precautions
Solution Approach 1:
The patent replaces the welding process (thermal/chemical joining) with a mechanical press-fitting process. The cap is joined to the nut body through radial pressing and forming of retaining lugs, eliminating the need for welding operations, heat treatment controls, and associated complexity while achieving equivalent media-tight connection reliability.
2Reliability
If high forming force is applied to press ring collar onto cap, then media-tight connection is formed, but anti-twist elements on bottom of press-in nut are damaged
Solution Approach 1:
The patent segments the forming process into two distinct stages: first forming retaining lugs with low force to achieve captive fixation, then later applying high forming force to press the ring collar onto the cap for media-tight connection. This temporal segmentation allows the anti-twist elements to be protected during the critical high-force operation while still achieving the required sealing reliability.
Solution Approach 2:
The patent performs preliminary action by first forming the retaining lugs and achieving captive fixation before performing the high-force press-fitting of the ring collar. This preliminary captive fixation stabilizes the press-in nut during the subsequent high-force operation, preventing damage to the anti-twist elements while still achieving media-tight connection.
3Adaptability or versatility
If cap nut is produced as two separate pieces, then assembly flexibility is improved, but production complexity and cost increase
Solution Approach 1:
The patent merges the cap and nut body into a single pre-assembled unit through the press-fitting process that forms retaining lugs and media-tight connections. This integration simplifies production by reducing the number of separate components and assembly steps, while still maintaining the flexibility to produce different cap heights and configurations as needed for various applications.
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 approach enables cost-effective, space-optimized, and lightweight production of media-tight press-in connections with reduced risk of damage to anti-twist elements, meeting stringent sealing requirements like IP67 and IP68, while allowing for easy adjustment of cap height and use in various applications.
Implementation Method 1
the ring collar is bent in the circumferential direction... in such a way that the cap is prefixed captively by the ring collar
Implementation Method 2
a form-locking and/or friction-locking connection is formed with the hole edge of the component
Implementation Method 3
a form-locking and/or friction-locking connection is formed with the hole edge of the component
Implementation Method 4
the material flows from the component into the undercut area of the press-in nut
Implementation Method 5
a press-in nut can also be attached to the sheet metal by buckling the collar
Data Source
AI summary
A press-in nut is formed as a cap nut and has a nut body with a through hole, which is closed by a cap under formation of a blind hole. This is provided to obtain a media-tight connection with the nut body. The nut body has a ring collar at the top. In a pre-assembled state, the ring collar is only at least partially bent over, so that the cap is only held captively, without a media-tight connection being formed. The desired media-tight connection is only formed when press-fitting into a component.