Protective Fuse Structure With Downward Shielding for Arc Suppression
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Solution Overview
Problem
Conventional fuse elements for high voltage and large current applications are prone to arc discharge when fused, leading to potential destruction of insulating cases and lack a simultaneous overcurrent cutoff function using a cutoff signal.
Innovation Solution
A protective element design featuring a fuse element, insulating case, terminals, an insulating member with an opening portion, a shielding member that moves downward to cut the fuse element, and a locking member, which includes a heat generating body to soften the locking member and facilitate the shielding member's downward movement for effective arc discharge prevention and overcurrent cutoff.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If metals such as copper are used as fuse element materials to curb arc discharge, then arc discharge is reduced, but the melting point requirement conflicts with the need for lower melting point materials
Solution Approach 1:
The fuse element uses a composite structure with a copper base material that has a low melting point coating layer on its surface. The copper core provides low resistance and high melting point characteristics to reduce arc discharge, while the coating layer enables the fuse to melt at a lower temperature for reliable current cutoff.
2Temperature
If a robust and highly heat-resistant material such as ceramic is used as insulating case material, then heat resistance is improved, but the size of the insulating case must be increased
Solution Approach 1:
The insulating case uses a localized ceramic coating applied only to the inner surface or specific high-heat zones, rather than using solid ceramic throughout. This provides heat resistance where needed while maintaining a compact overall size and reducing weight compared to a full ceramic construction.
3Power
If conventional fuse elements are designed for high voltage and large current, then they can handle high power applications, but they lack the ability to provide cutoff function using a cutoff signal
Solution Approach 1:
The fuse element incorporates a dual-function design: it maintains its traditional overcurrent protection capability through thermal melting, while also including a magnetic or electric actuation mechanism that allows it to be triggered by an external cutoff signal. This enables the same device to perform both passive thermal protection and active controlled cutoff functions.
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 solution reliably cuts off current, prevents large-scale arc discharge, reduces the size and weight of the insulating case, and provides both overcurrent cutoff and signal-based cutoff functions for high voltage and large current applications.
Implementation Method 1
a heat generating body configured to generate heat, and a locking member configured to restrain downward movement of the shielding member, wherein as the shielding member moves downward, the locking member is inserted into the opening portion or the separation portion
Data Source
AI summary
A protective element includes a fuse element, an insulating case, a first terminal, and a second terminal, and also includes an insulating member disposed close to or in contact with the fuse element and having an opening portion or a separation portion formed therein, a shielding member configured to move downward to divide the fuse element, a pressing unit configured to press the shielding member downward, and a locking member configured to restrain downward the shielding member, wherein the shielding member has a convex portion that protrudes toward the fuse element, the convex portion has a tip end disposed at a lower end portion of the convex portion and extends in a width direction, the tip end has a first inclined blade which extends downward as nearing one side in the width direction, and the first inclined blade overlaps a region half the length of the fuse element in the width direction.