Wire-Wound Fuse Resistor With Low-Melting Connection Part
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Solution Overview
Problem
Conventional wire-wound resistors have high failure rates at surge-resistant soldering points due to poor soldering quality, leading to increased contact resistance and potential loosening under transient energy surges, and conventional fuse resistors have high fusing temperatures that can cause circuit damage.
Innovation Solution
A surge-resistant wire-wound resistor with electroplated metal layers on soldering points and a low-temperature fuse resistor design featuring a connection part with a lower melting point than the winding wires, both incorporating insulating layers and electroplated caps to enhance soldering reliability and reduce fusing temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional soldering methods are used on wire-wound resistors, then the manufacturing process is simple, but the soldering points have high failure rates under transient energy surges
Solution Approach 1:
The patent applies electroplating to create a multi-layer metal structure (base metal layer, intermediate layer, and soldering layer) specifically at the soldering points of the wire-wound resistor. This local enhancement of material properties at critical locations improves surge resistance and soldering reliability without changing the entire resistor structure, thereby resolving the contradiction between reliability improvement and device complexity.
2Reliability
If high melting point wire material is used in fuse resistors, then the electrical properties and resistance are improved, but the fusing temperature is too high causing circuit damage
Solution Approach 1:
The patent creates a temperature gradient structure where the connection part has lower melting point material than the winding wires. This allows the connection part to fuse first at a controlled temperature, providing circuit protection before the high melting point winding wires reach damaging temperatures, thus resolving the contradiction between electrical properties and safe fusing temperature.
Solution Approach 2:
The patent designs the connection part with lower melting point material as a protective element that will fuse beforehand to prevent catastrophic failure of the entire circuit. This preemptive measure absorbs the surge energy and protects the main winding wires and connected circuits from damage, embodying the beforehand cushioning principle.
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 significantly reduces the failure rate of surge-resistant soldering points to less than 0.1 ppm and provides effective circuit protection by ensuring reliable connections and controlled fusing temperatures, applicable in various electrical circuits and automotive systems.
Implementation Method 1
the first cap and the second cap are respectively electroplated with a first cap electroplated layer and a second cap electroplated layer
Implementation Method 2
the connection part has a lower melting point than the first winding wire and the second winding wire
Data Source
AI summary
The present invention relates to a wire-wound fuse resistor, which has: an insulating rod which has a first end and a second end; one metal wire having a wire head and a wire tail, being helically wound around the insulating rod from the first end to the second end, and being cut at a middle portion thereof to form a first winding wire and a second winding wire, which are separated from each other; a connection part disposed at the cut portion for electrical connection between the first winding wire and the second winding wire, in which the melting temperature of the connection part is lower than that of the one wound metal wire, wherein the connection part is cut off depending on a predetermined melting temperature or melting speed of the wire-wound fuse resistor.