Offset-Seam Shrink Cap for Stable High-Voltage Insulation
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Solution Overview
Problem
Existing shrink caps with welded or embossed seams are prone to mechanical instability, leading to potential breakage and compromised protective functions, especially when the seams are bent by 90° or more. This instability also affects the high-voltage strength and dielectric properties of the shrink cap.
Innovation Solution
The shrink cap design features a weld or embossed seam that is offset parallel to the plane of symmetry, allowing for a larger bending area without protruding beyond the cap's edges. The seam is bent over and preferably applied to the end face of the shrink cap, either directly or with the interposition of a joining agent, to enhance mechanical stability and high-voltage resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the welded or embossed seam is bent by 90° or more to eliminate sharp edges, then the risk of injury and damage is reduced, but the shrink cap becomes mechanically less stable and can break more easily
Solution Approach 1:
The weld seam is intentionally positioned asymmetrically, offset from the central plane of symmetry of the shrink cap. This asymmetric positioning allows the seam to be bent over and attached to the end face without creating excessive stress concentrations that would occur with symmetric bending, thereby maintaining mechanical stability while eliminating sharp edges
Solution Approach 2:
The weld seam is pre-positioned offset from the center before the shrinking process. This preliminary asymmetric positioning enables the subsequent bending operation to be performed more gently, attaching the seam to the end face without subjecting the shrink cap to severe deformation that would compromise its mechanical integrity
2Reliability
If the welded or embossed seam is created by pressing one end together and joining longitudinal halves, then the seam provides closure, but it creates a stiff and rigid seam that protrudes with a sharp edge
Solution Approach 1:
The weld seam is pre-positioned asymmetrically during the joining process, before the shrink cap is shrunk onto the component. This preliminary offset positioning allows the seam to be subsequently bent over and attached to the end face, transforming the harmful sharp edge into a beneficial feature that enhances mechanical stability and electrical insulation
Solution Approach 2:
The sharp edge that initially protrudes from the weld seam is converted into a benefit by bending the seam over and attaching it to the end face. The previously harmful sharp edge becomes part of the reinforced end face structure, improving both mechanical stability and high-voltage resistance
3Object-affected harmful factors
If the shrink cap is used to encase temperature-dependent switches, then protection from dirt and moisture is provided, but the sharp edges can damage the coil or switching mechanism
Solution Approach 1:
The weld seam is pre-positioned asymmetrically before shrinking, enabling it to be bent over and attached to the end face in advance. This preliminary action ensures that when the shrink cap is installed on the temperature-dependent switch, the seam does not protrude with a sharp edge that could damage the coil or switching mechanism
Solution Approach 2:
The potentially harmful sharp edge of the weld seam is converted into a beneficial feature by bending it over and attaching it to the end face. This transformation eliminates the risk of damage to the coil while maintaining the protective function of the shrink cap enclosure
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 design significantly reduces the risk of injury and damage from sharp edges, enhances mechanical stability, and improves the high-voltage strength of the shrink cap, achieving a high-voltage resistance of 3.5 kV or more.
Implementation Method 1
They are then shrunk using hot air to create a sheath that protects the component
Implementation Method 2
the welded or embossed seam is created, for example, with the help of two welding dies that apply pressure and heat to the end of the shrink tubing section from opposite sides
Data Source
Figure 1~3B
Figure 4
AI summary
A shrink cap (10) for sliding onto a temperature-dependent switch (12) comprises an open first end (18) for sliding onto the switch (12) and a closed second end (20) which is closed by a welded or stamped seam (22) extending from a closed end face (24) arranged in the region of the second end (20) and resulting from the welded or stamped seam (22). In a region between the first end (18) and the end face (24), the shrink cap (10) is essentially mirror-symmetrical to a first plane of symmetry (30). The welded or stamped seam (22) is arranged at its end section (34) adjacent to the end face (24) and offset parallel to the first plane of symmetry (30).