Surge Protector Terminal-Spring Joint for Stable Solder Strength
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Solution Overview
Problem
The traditional soldering interface between the spring and the metal oxide varistor electrode in surge protection devices is deficient in terms of solder volume and uniformity, leading to unstable soldering strength and compromised operation.
Innovation Solution
Incorporating features such as openings, bends, and protrusions in the soldering joints of the surge protection device to facilitate controlled application of soldering paste, ensuring a reliable thermal link between the spring and the metal terminal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional soldering interface is used between spring and MOV electrode, then the structure is simple, but the soldering strength is unstable due to insufficient solder volume and non-uniform application
Solution Approach 1:
The flat surface of the spring is designed with a specific structure featuring a bend at one end that forms a gap between the flat surface and the metal terminal. This local structural modification creates a controlled space for solder paste application, ensuring uniform distribution and adequate volume of solder in the soldering joint, thereby improving soldering strength without significantly complicating the overall device structure
Solution Approach 2:
The gap formed by the bend in the flat surface is pre-designed to control the amount of solder paste before soldering. This preliminary structural arrangement ensures that the solder paste is uniformly applied and properly positioned between the spring and metal terminal, preventing both insufficient and excessive solder volume issues before the soldering process begins
2Reliability
If sufficient solder paste is applied to ensure reliable thermal link, then soldering strength improves, but air bubbles may form in the soldering paste compromising the connection
Solution Approach 1:
The flat surface structure with its inherent gap creates a controlled porous-like space that allows air bubbles to escape during the soldering process. The gap provides an escape path for trapped air, preventing bubble formation in the final solder joint while still maintaining sufficient solder paste volume for reliable thermal connection between the spring and metal terminal
3Stability of the object's composition
If uniform solder paste application is achieved, then soldering strength stabilizes, but the traditional method lacks control over solder volume and distribution
Solution Approach 1:
The flat surface is designed with a bend at one end, creating a three-dimensional gap structure rather than a simple planar interface. This dimensional change provides a controlled space that naturally regulates solder paste volume and distribution, ensuring uniform application and stable soldering strength without requiring complex external control mechanisms during manufacturing
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 enhances soldering strength and reliability by controlling the amount of soldering paste, preventing air bubble formation, and maintaining a consistent gap, thereby ensuring a stable open circuit during overvoltage conditions.
Implementation Method 1
The spring has a flat surface that is connected to the metal terminal using a soldering paste
Data Source
AI summary
A surge protection device includes a metal terminal and a spring. The metal terminal is located between two metal oxide varistors, where the metal terminal extends beyond the metal oxide varistors. The spring has a flat surface that is connected to the metal terminal using a soldering paste. The flat surface has a bend on one end which forms a gap between the flat surface and the metal terminal.