Protective Fuse Structure With Movable Shield for Arc Suppression
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Solution Overview
Problem
High voltage/high current fuses do not effectively prevent large-scale arc discharge when fusing, leading to insulating case breakdown, and lack both overcurrent cutoff and signal cutoff functions.
Innovation Solution
A protective element with a fuse element, insulating case, and shielding member that moves to cut the fuse element, using a heat-generating body to soften a locking member and allow the shielding member to cut the fuse, incorporating materials with high tracking resistance and a stacked metal layer structure to reduce arc discharge and enable both overcurrent cutoff and signal cutoff.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a metal fuse element with low resistance and high melting point is used to suppress arc discharge, then arc discharge is suppressed, but the insulating case size must be enlarged to accommodate the additional components
Solution Approach 1:
The shielding member is nested within the insulating case, moving through openings in the insulating members when activated. This allows the arc suppression mechanism to be contained within the existing case volume rather than requiring external space, resolving the contradiction between arc discharge suppression and case size reduction
Solution Approach 2:
The shielding member transitions from a static to a dynamic configuration, remaining retracted during normal operation and only extending through the openings when heat-generating body activation is required. This dynamic behavior allows compact packaging while maintaining arc suppression capability when needed
2Reliability
If a two-piece fuse element structure is used for overcurrent cutoff, then overcurrent protection is achieved, but the device lacks signal cutoff functionality
Solution Approach 1:
The fuse element structure is designed to serve dual functions: the first and second elements provide overcurrent cutoff through fusion, while the same elements also enable signal cutoff when the shielding member is activated by the heat-generating body. This multi-functionality resolves the contradiction between reliability and adaptability
3Strength
If ceramic material is used for the insulating case to ensure ruggedness and heat resistance, then durability is improved, but the case size and weight increase
Solution Approach 1:
The insulating members (first and second) are positioned locally at critical areas where arc discharge and heat generation occur, providing targeted thermal and electrical insulation. This localized approach maintains necessary heat resistance and ruggedness at the critical zones while allowing the overall case to be smaller and lighter than a fully ceramic construction
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
Prevents large-scale arc discharge, allows for a smaller and lighter insulating case, and achieves both overcurrent cutoff and signal cutoff functions in high voltage/high current applications.
Implementation Method 1
a heat-generating body that heats and softens the locking member or a fixing member fixing the locking member
Data Source
AI summary
A protective element includes: a fuse element including a first end portion and a second end portion; first and second insulating members each having an opening or a separation part, the first and second insulating members being disposed in a state proximal to or in contact with the fuse element; a shielding member movable in a moving direction that allows the shielding member to insert into the opening or the separation part so as to divide the fuse element; a locking member that suppresses movement of the shielding member; a pressing member that press the shielding member; and a heat-generating body configured to heat the locking member or a fixing member of the locking member.