Self-Piercing Fastening Sleeve for High-Strength Metal Components
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Solution Overview
Problem
Existing fastening sleeves are limited to insertion into relatively soft materials and cannot effectively form opening reinforcements in high-strength metallic components due to diameter restrictions and deformation during punching.
Innovation Solution
A self-piercing metallic fastening sleeve with a hollow cylindrical shaft, flange, and stamping ring, allowing insertion into high-strength metallic components without pre-drilling, using a punch and die to create a frictional connection and displacement of material for secure fastening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fastening sleeves are inserted into pre-drilled openings, then they can be easily installed in soft materials, but they cannot effectively form opening reinforcements in high-strength metallic components due to diameter restrictions and deformation during punching
Solution Approach 1:
The fastening sleeve is prepared in advance with a specific geometric configuration including a shaft with reduced wall thickness in the punching region and a flange with a stamping ring. This preliminary design enables the sleeve to undergo controlled plastic deformation during the punching process, allowing it to be inserted into high-strength metallic components without pre-drilling while maintaining structural integrity and fastening strength.
2Strength
If fastening sleeves are punched into high-strength metallic components, then opening reinforcements can be formed, but the sleeves deform during punching due to diameter restrictions
Solution Approach 1:
The fastening sleeve features non-uniform wall thickness distribution, with the wall thickness being reduced specifically in the punching region (first shaft region) while maintaining adequate thickness in other regions. This local quality variation allows the punching region to deform plastically during insertion into high-strength components, forming the opening reinforcement, while other regions maintain their shape and structural integrity.
Solution Approach 2:
The fastening sleeve is designed with variable geometric parameters along its length, particularly the wall thickness parameter that changes from the punching region to the functional region. This parameter change enables controlled plastic deformation during punching, allowing the sleeve to adapt to high-strength metallic components while maintaining sufficient structural properties for fastening.
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
Enables single-step insertion and secure fastening in high-strength metallic components with high pull-out forces, suitable for connecting additional components via functional regions, and withstands punching forces up to 90 kN and setting forces up to 120 kN.
Implementation Method 1
pressing the stamping ring (18) into the component (3), whereby material of the component (3) is displaced in the direction of the first shaft region (20) and the fastening sleeve (1) is arranged captively in the component (3) due to a frictional connection
Implementation Method 2
the fastening sleeve (1) is arranged captively in the component (3) due to a frictional connection
Data Source
Figure 1~3
Figure 4a~7
Figure 8~9
AI summary
A self-piercing metallic fastening sleeve (1) is adapted to form an opening reinforcement in a metallic component (3), preferably in a high-strength metallic component (3).The fastening sleeve (1) has the following features: a hollow cylindrical shaft (10) with a first (12) and a second axial end (14), a flange (16) which is arranged between the first (12) and the second axial end (14) and is formed so as to be closed and circumferential around the shaft (16), wherein the first (12) and the second axial end (14) protrude beyond the flange (16), the flange (16) has, on the side facing the first axial end (12), a stamping ring (18) which is arranged adjacent to the shaft (10), and a first shaft region (20) between the flange (16) and the first axial end (12) provides a punching and fastening region for the captive fastening of the fastening sleeve (1) to the metallic component (3), wherein the punching and fastening region is preferably not radially expandable, and a second shaft region (30) between the flange (16) and the second axial end (14) provides a functional area.