Fuse Device With Interlocking Cover And Grooved Arc Path
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Solution Overview
Problem
Conventional fuse devices face challenges in high current applications due to increased arc discharge impact, thermal stress, and the risk of the case member being dislodged or damaged during current interruption, which can lead to unexpected damage such as short circuits, especially when trying to increase current ratings and prevent arc discharge.
Innovation Solution
A fuse device design featuring a base member and a cover member with a fitting projection and opening system made of nylon-type plastic, which enhances impact resistance and prevents the cover member from disengaging during arc discharge, using a low melting point fuse element with a high melting point metal layer for rapid blowout and improved thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the fuse element size is increased to reduce resistance for higher current ratings, then the current rating is improved, but the arc discharge impact increases in proportion to the size increase
Solution Approach 1:
The patent utilizes the arc discharge phenomenon by providing a groove structure that guides the arc along a predetermined path. The arc, which would otherwise cause random damage, is redirected to follow the groove from one electrode to the other, containing the harmful effect and preventing case member damage while still achieving high current rating interruption.
2Temperature
If the case member is made larger to withstand thermal influence at higher current ratings, then the thermal resistance is improved, but the impact resistance and structural stability worsen due to increased internal pressure and thermal stress
Solution Approach 1:
The case member is segmented into multiple functional regions: a groove structure for arc guidance, a fitting projection-opening mechanism for structural interlocking, and reinforced wall portions. This segmentation allows each region to specialize in handling specific stresses (thermal, mechanical, or arc-related) without requiring the entire case to be oversized, thereby maintaining impact resistance while managing thermal influence.
3Power
If the fuse element is made larger to reduce resistance for high current applications, then the current carrying capacity is improved, but the internal pressure and thermal stress on the case member increase causing potential dislodgement or damage
Solution Approach 1:
The fitting projection and opening structure is pre-configured in the case member before operation. This preliminary structural arrangement ensures that when internal pressure and thermal stress increase during high current operation, the interlocking fitting projection-opening mechanism is already in place to prevent case member dislodgement or damage, allowing the fuse to handle higher current ratings safely.
4Power
If conventional fuse elements are used for high current ratings, then the current capacity is improved, but the blowout speed decreases and mounting properties deteriorate
Solution Approach 1:
The fuse element uses a layered structure with different melting points (low melting point solder layer and high melting point metal layer). This parameter variation allows the fuse to maintain structural integrity during reflow mounting while enabling rapid blowout at operating temperatures. The low melting point layer provides quick response for blowout, while the high melting point layer ensures mounting stability, thus achieving both high current rating and fast blowout speed.
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 design effectively prevents the cover member from disengaging and reduces the risk of damage by enhancing resistance to upward pressure and thermal stress, allowing for higher current ratings while maintaining reliable interruption of the current path without causing short circuits.
Implementation Method 1
a fuse element disposed between the base member and the cover member; when a current higher than the rated current flows, the self-heating causes blowout of the fuse element to interrupt the current path
Implementation Method 2
using a low melting point fuse element with a high melting point metal layer for rapid blowout
Data Source
AI summary
Provided is a fuse device used for high rating and high current applications excellent in impact resistance at the time of current interruption, and capable of preventing falling off of the case. The fuse device includes: a base member; a cover member fitted to the base member and covering a surface of the base member; and a fuse element mounted on the surface of the base member; wherein one of the base member and the cover member is provided with a side wall intersecting with the plane of the surface of the base member and including an opening formed therein, and the other of the base member and the cover member is provided with a fitting projection projecting outward from a plane intersecting with the plane of the surface of the base member and fitted into the opening of the side wall.