Terminal-Equipped Wire Crimping for Thin-Wire Strength and Conductivity
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Solution Overview
Problem
Existing technologies face challenges in achieving a balance between connection strength and electrical resistance in small-diameter electric wires used in vehicles, particularly when crimping thin wires with a diameter of 0.35 sq (mm²) or less, as excessive compression damages strands and increases resistance, while insufficient compression weakens the connection.
Innovation Solution
A terminal-equipped electric wire design featuring a coated conductive wire with a tension member and conductive wire disposed on its outer periphery, where the conductive wire is crimped from the entire circumference, and the tension member's strength exceeds that of the conductor, minimizing deformation and maintaining contact area, thus balancing tensile strength and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If strong compression is applied during crimping to break the oxide film and improve conductivity, then electrical resistance decreases, but the strands are damaged and tensile strength at the connection part is significantly lowered
Solution Approach 1:
The invention divides the crimping process into two distinct stages: a first crimping process that applies strong compression to break the oxide film and ensure good electrical contact, and a second crimping process that applies weaker compression to consolidate the connection without damaging the strands. This segmentation allows each stage to optimize for its specific purpose, resolving the contradiction between achieving low resistance and maintaining high tensile strength.
Solution Approach 2:
The first crimping process is performed as a preliminary action before the second crimping process. By pre-breaking the oxide film through strong compression in the first stage, the subsequent second stage can use milder compression that is sufficient for mechanical consolidation without causing strand damage. This preliminary action sequence enables both good conductivity and high connection strength.
2Strength
If less compression is given during crimping to preserve strand integrity, then tensile strength is maintained, but the oxide film breaking is insufficient and resistance at the connection part increases
Solution Approach 1:
The crimping process is segmented into two stages with different compression levels. The first stage uses strong compression specifically targeted at breaking the oxide film, while the second stage uses milder compression for mechanical consolidation. This segmentation allows the system to achieve both low resistance (through adequate oxide film breaking in stage 1) and high tensile strength (through gentle consolidation in stage 2).
Solution Approach 2:
The crimping is performed as periodic action with two distinct compression cycles. The first cycle applies high compression to break the oxide film, then pauses, and the second cycle applies milder compression for consolidation. This periodic application of different compression levels resolves the contradiction by ensuring adequate oxide film breaking without excessive strand damage.
3Ease of manufacture
If a single crimping process is used to balance conductivity and tensile strength, then the process is simple, but it is difficult to control the balance between conductivity and tensile strength, especially for thin wires
Solution Approach 1:
The crimping process is segmented into two distinct processes with different compression characteristics. The first crimping process is optimized for breaking the oxide film (prioritizing conductivity), while the second is optimized for mechanical consolidation (prioritizing tensile strength). This segmentation provides clear control parameters for each stage, making it easier to achieve the desired balance between conductivity and strength, particularly for thin wires where the margin for error is small.
Solution Approach 2:
The invention changes the compression rate parameter between two distinct crimping processes. The first process uses a higher compression rate to break the oxide film, while the second process uses a lower compression rate to consolidate without damage. By explicitly defining different parameter ranges for different stages, the invention provides a controllable method to achieve both good conductivity and high tensile strength, resolving the difficulty of balancing these properties in a single process.
4Weight of moving object
If the diameter of the electric wire is reduced for weight reduction, then vehicle weight decreases, but the scope of appropriate crimping conditions that satisfy both connection strength and electric resistance becomes smaller
Solution Approach 1:
The segmentation of crimping into two stages with different compression levels provides greater adaptability for thin-wire applications. The first stage with higher compression ensures adequate oxide film breaking even for very thin wires, while the second stage with milder compression prevents strand damage. This segmented approach expands the scope of appropriate crimping conditions for thin wires, enabling weight reduction while maintaining connection quality.
Solution Approach 2:
By implementing two distinct crimping processes with different compression rate parameters, the invention expands the usable parameter space for thin-wire crimping. The first process uses higher compression rates suitable for breaking oxide films on thin conductors, while the second uses lower rates appropriate for consolidating thin-wire connections. This parameter differentiation increases the scope of appropriate crimping conditions, allowing thin wires to be used effectively while maintaining both low resistance and high connection strength.
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 ensures excellent crimping workability, achieving both high connection strength and low resistance, reducing the number of components and operational steps, and preventing damage to the tension member, especially effective for thin wires.
Implementation Method 1
strong compression at the time of crimping the conductive wire crimp part
Implementation Method 2
strands forming the conductor arc in contact with the conductive wire crimp part of the crimp terminal, thereby achieving conduction with the crimp terminal
Data Source
AI summary
A terminal-equipped electric wire includes a terminal and a coated conductive wire, which are electrically connected to each other. A crimp part of the terminal is a part that crimps the coated conductive wire and includes a conductive wire crimp part crimping a conductive wire exposed from a coating on a tip-end side of the coated conductive wire, and a coating crimp part crimping the coating of the coated conductive wire. The coated conductive wire includes a tension member disposed in an approximate center of a cross section, and a conductive wire including a plurality of conductors disposed on an outer periphery of the tension member. The tension member includes a plurality of strands. The conductive wire is crimped at the conductive wire crimp part from the entire circumference of the circumferential direction of the conductive wire. Preferably, a tensile strength of the tension member is greater than that of the conductive wire.