Self-Clinching Fastener Lug Geometry for Sealed Metal Joints
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Solution Overview
Problem
Existing self-attaching construction elements struggle to provide sufficient torque-out and push-out resistance while maintaining a fluid seal, particularly in applications like electric vehicles where air decay requirements are stringent.
Innovation Solution
A self-clinching construction element with a body portion and a punch portion, featuring a plurality of spaced apart lugs that encircle the punch portion, with a lug width ratio between 10% to 22% of the punch portion's maximum diameter, enhancing rotational and push-out resistance while improving sealing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional construction elements are installed by forcing them into the substrate to create a joint, then torque-out and push-out resistance are achieved, but fluid seal performance is insufficient
Solution Approach 1:
The construction element is divided into distinct functional segments: a body portion for structural strength, a punch portion for creating the anchoring engagement, and multiple lugs for distributing clamping force. This segmentation allows each part to optimize its function while working together to achieve both mechanical strength and fluid seal performance.
Solution Approach 2:
Different regions of the construction element have different geometric properties optimized for their specific functions. The lugs have specific width ratios (10-20% of punch portion diameter) to concentrate clamping force at critical sealing locations, while the overall element maintains structural integrity for torque-out and push-out resistance.
2Reliability
If the lug width is increased to improve sealing contact, then fluid seal performance improves, but torque-out and push-out resistance decrease
Solution Approach 1:
The invention optimizes the lug width as a specific parameter, defining it as 10-20% of the punch portion maximum diameter. This parameter range represents the optimal balance point where sufficient sealing contact is achieved without compromising the structural strength needed for torque-out and push-out resistance.
3Ease of manufacture
If the construction element design is simplified for ease of manufacture, then manufacturing cost decreases, but sealing performance becomes insufficient
Solution Approach 1:
The punch portion serves multiple functions: it creates the anchoring engagement in the substrate, defines the overall diameter for lug width calculations, and provides the reference geometry for ensuring proper fit and seal. This multi-functionality reduces the need for additional separate components or complex manufacturing steps.
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
The proposed construction element achieves enhanced torque-out and push-out resistance while significantly reducing air decay, meeting and exceeding industry standards for fluid seal integrity.
Implementation Method 1
forcing the construction element into the substrate (i.e., sandwiching the construction element and the metal panel between a drive mechanism and an anchoring block) such that material of the substrate plastically deforms and conforms to select features and profiles of the construction element
Data Source
AI summary
A self-clinching construction element for attachment to a plastically deformable metal substrate includes a body portion with a central axis, the body portion has an annular-shaped surface extending in a direction perpendicular to the central axis. A punch portion is coaxial with the central axis and extends from the body portion such that the annular-shaped surface encircles the punch portion. A plurality of spaced apart lugs axially project outwards from the annular-shaped surface and extending radially outwards from the outer peripheral surface of the punch portion. A lug of the plurality of spaced apart lugs has a maximum width that is less than a maximum width of the punch portion, and a percentage ratio between the maximum width of the lug and the maximum width of the punch portion is in a range of 10% to 22%.