Crimp Tool Surface Roughness for Wire Barrel Uniformity
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Solution Overview
Problem
Conventional crimping methods for electrical wires concentrate stress on terminal wire barrels, leading to partial thinning and potential quality issues in the crimped connections.
Innovation Solution
A crimp tool with a curved face having a surface roughness greater than the placement face, ensuring uniform force distribution and preventing slippage, is used to crimp terminals with wire barrels to a core wire, maintaining even thickness and quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wire barrels are crimped to a core wire using a conventional crimp tool with smooth surfaces, then the crimping process is simple and fast, but stress is concentrated at the ends of the wire barrels causing them to be pushed upward and forming thinner portions
Solution Approach 1:
The patent applies local quality by differentiating the surface roughness of different parts of the crimp tool. The curved face (pressing surface) is given a larger surface roughness (Ra2) compared to the placement face (Ra1), creating localized friction characteristics that prevent slippage and stress concentration at specific locations during crimping.
Solution Approach 2:
The patent changes the physical parameter of surface roughness to resolve the contradiction. By increasing the surface roughness of the curved face (Ra2 > Ra1), the tool creates sufficient friction to hold the wire barrels in place during crimping, preventing the stress concentration and thinning that occurs with smooth surfaces.
2Reliability
If the curved face of the crimp tool has a larger surface roughness than the placement face, then slippage is suppressed and uniform force is applied to wire barrels, but the manufacturing process becomes more complex
Solution Approach 1:
The patent implements local quality by applying different surface roughness characteristics to different functional areas of the crimp tool. The curved face requires higher roughness (Ra2) for friction-based slippage prevention, while the placement face maintains lower roughness (Ra1) for proper positioning, creating localized functional zones.
Solution Approach 2:
The patent modifies the surface roughness parameter (Ra) as a key differentiator between tool surfaces. By setting Ra2 > Ra1 with specific ranges (0.2≤Ra2≤1.0μm), the patent transforms a simple crimping tool into a reliable device that prevents terminal thinning through controlled friction.
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 effectively prevents partial thinning of terminals, ensuring high-quality connections by uniformly distributing stress and suppressing slippage, as demonstrated in various embodiments with surface roughness ratios between 0.2μm and 1.0μm.
Implementation Method 1
the curved face comes into close contact with the wire barrels in a state in which slipping is unlikely to occur due to the frictional force thereof
Data Source
AI summary
A production method for a terminal-equipped electrical wire in which a terminal including a bottom plate portion and a pair of wire barrels extending sideward from the bottom plate portion is crimped to a core wire exposed at an end of an electrical wire, includes: a step of placing the core wire on the bottom plate portion; and a step of allowing the wire barrels to surround the core wire and be crimped to the core wire using a crimp tool, wherein the crimp tool includes a first tool having a placement face on which the bottom plate portion and the core wire are placed, and a second tool having a curved face for holding and curving the wire barrels between the curved face and the placement face, and a surface roughness Ra2 of the curved face is larger than a surface roughness Ra1 of the placement face (Ra2>Ra1).