Contact Connection Structure with Smooth Surface
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Solution Overview
Problem
Conventional contact connection structures between terminals exhibit high contact resistance due to uneven surfaces caused by rolling scratches on copper alloy base materials, leading to increased size and complexity when attempting to reduce resistance.
Innovation Solution
The terminals are manufactured with smooth outer surfaces through polishing and plating, ensuring the contact surfaces match the apparent contact area, thereby reducing contact resistance without enlarging or complicating the terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact load between contact parts is increased to reduce contact resistance, then contact resistance decreases, but the terminals increase in size and complexity
Solution Approach 1:
The invention applies local quality by creating a specific smooth surface structure at the contact portion of the female terminal, while other parts of the terminal can maintain their conventional rolled bar material structure. This localized treatment reduces contact resistance at the critical contact interface without requiring the entire terminal to be enlarged or complicated.
Solution Approach 2:
The invention changes the surface roughness parameter of the contact surface from the conventional uneven rolled surface to a smooth surface with controlled roughness (Ra 0.8 μm or less). This parameter change allows for better contact between plating layers and base material, reducing contact resistance without increasing terminal size or complexity.
2Reliability
If the contact load between contact parts is increased to reduce contact resistance, then contact resistance decreases, but the terminals increase in size
Solution Approach 1:
The smooth surface treatment is applied only to the contact portion of the female terminal where it interfaces with the male terminal. This localized approach reduces contact resistance without requiring the entire terminal structure to be enlarged, thereby avoiding increased weight.
Solution Approach 2:
The smooth surface is formed on the contact portion before plating is applied. This preliminary surface preparation ensures that the plating layer adheres properly and creates an uniform contact surface, reducing contact resistance without requiring additional terminal size or weight.
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 approach stabilizes contact resistance reduction across various contact loads, particularly with noble metal plating layers like silver and gold, by maintaining a consistent conduction area equal to the apparent contact area, effectively addressing the issue of high contact resistance.
Implementation Method 1
the elastically flexible part flexibly deforms to upper surface side to permit insertion of the tab portion
Implementation Method 2
With the restoring force of the elastically flexible part as a contact load, the contact surfaces of the indent portion of the female terminal and the tab portion of the male terminal come into electrical contact with each other
Implementation Method 3
Electric current flows through the contact surfaces to flow electrical current between the female terminal and the male terminal
Data Source
Figure 1A~1B
Figure 2A~3
Figure 4
AI summary
A contact connection structure includes: a first contact part provided in a first terminal, having a first plating layer formed on an outer surface of a first base material, and having an indent portion protruding from a plane formed by the outer surface of the first base material; and a second contact part provided in a second terminal, having a second plating layer formed on an outer surface of a second base material, and configured to be in contact with the indent portion. At least one of the outer surface of the first base material at the first contact part and the outer surface of the second base material at the second contact part is formed as a smooth surface with smaller surface roughness than surface roughness of a rolled bar material.