Metal Terminal Fitting Recess Arrangement for Oxide Removal
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Solution Overview
Problem
Existing terminal connectors face challenges in reducing contact resistance and improving holding force due to oxide layers on conductors, especially when using materials like aluminum, and suffer from reduced mechanical strength with high compression rates.
Innovation Solution
The terminal connector features a crimping portion with recesses arranged at an angle of 85 to 95 degrees to the conductor's extending direction, overlapping in the extending direction, which increases the edge length and area for oxide removal and enhances holding force while maintaining a moderate compression rate to balance mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If recesses are arranged to overlap entirely in the extending direction of the conductor, then the structure is simple, but the holding force of the crimping portion deteriorates due to gaps between aligned rows of recesses
Solution Approach 1:
The patent transitions from a one-dimensional linear arrangement of recesses to a two-dimensional grid pattern. Recesses are arranged in multiple rows and columns with crossing sides at angles of 85-95 degrees, creating overlapping patterns that eliminate gaps and significantly enhance the holding force between the crimping portion and conductor.
2Reliability
If the compression rate of the crimping portion is decreased (high compression), then the oxide layer on the conductor is sufficiently removed and contact resistance is reduced, but the mechanical strength and tensile strength of the terminal connector are reduced
Solution Approach 1:
The crimping portion is segmented with multiple recesses arranged in a grid pattern, creating numerous small contact zones. This segmentation allows the crimping force to be distributed across multiple points, enabling effective oxide layer removal and low contact resistance while maintaining overall structural integrity and mechanical strength through the distributed reinforcement pattern.
Solution Approach 2:
The recesses create localized zones of high compression specifically at the conductor-crimping portion interface, where oxide layer removal is needed. The crossing sides at 85-95 degree angles concentrate the crimping force at these local contact points, achieving low contact resistance without requiring high overall compression that would compromise the entire connector's mechanical strength.
3Adaptability or versatility
If aluminum or other materials that easily form oxide layers are used for the conductor, then the conductor is suitable for various applications, but the oxide layer cannot be sufficiently removed even with recesses formed on the crimping portion, resulting in insufficient contact resistance reduction
Solution Approach 1:
The patent uses a two-dimensional grid arrangement of recesses with crossing sides at 85-95 degree angles, creating a dense pattern of contact edges. This multi-directional arrangement increases the total edge length and contact perimeter, providing sufficient mechanical action to remove tenacious oxide layers from aluminum and other reactive conductor materials, achieving low contact resistance while maintaining material versatility.
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 effectively reduces contact resistance, improves cooling and heating ability, and increases the holding force of the connector by ensuring efficient oxide layer removal and mechanical stability.
Implementation Method 1
the conductor is pressed against the crimping portion so as to be plastically deformed in the extending direction of the conductor. Then, the oxide layer formed on the surface of the conductor rubs against opening edges of the recesses (or against the protusions) and is broken or removed therefrom.
Implementation Method 2
If a cycle of heating and cooling (cooling and heating cycle) is repeated in a state in that the crimping portion is crimped onto the electric wire, the conductor and the crimping portion are expanded and shrunk repeatedly. This causes a gap between the conductor and the crimping portion, and accordingly, a contact resistance may be reduced.
Data Source
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AI summary
A plurality of recesses 18 are formed on a surface of a wire barrel 16 where an electric wire 11 is provided. In a state before the electric wire 11 is crimped onto the wire barrel 16, at least one of sides comprising rims of an opening of each recess 18 of a quadrangular shape is a crossing side 19 crossing at an angle of from 85 degrees to 95 degrees to an extending direction. In a state before the electric wire 11 is crimped onto the wire barrel 16, the crossing sides 19 of a plurality of recesses 18 positioned adjacent to each other in the extending direction are so arranged as to overlap with each other in the extending direction.