Crimp Terminal Serration Depth Variation for Stable Connections

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Solution Overview

Problem

Conventional crimp-style terminals experience variability in swaging conductor wires, leading to unstable electrical connections and potential damage due to inconsistent crimping forces, which can result in high resistance and low mechanical fixing strength, especially when dealing with fine element wires.

Innovation Solution

A crimp-style terminal design featuring a U-shaped conductor crimp unit with cylindrical concave serrations of varying depths, where the leading-end serrations are deeper to ensure secure contact and reduce oxide film growth, and trailing-end serrations are shallower to minimize damage and facilitate easy intrusion, stabilizing both electrical and mechanical connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If uniform depth serrations are used in the conductor crimp unit, then the structure is simple, but the swaging variation is large and electrical connection is unstable

Engineering Contradiction:
Improveserration structureVSAvoidelectrical connection stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies local quality by differentiating the serration depths at different locations within the conductor crimp unit. The leading end features deeper serrations to effectively remove oxide films and ensure stable electrical connection, while the trailing end has shallower serrations to minimize conductor damage. This spatial variation in serration depth optimizes both electrical and mechanical connection properties at different zones of the crimp unit.

Inventive Principle:
Principle #3Local quality

2Reliability

If deeper serrations are used to ensure stable electrical connection, then oxide film removal is improved, but conductor damage increases

Engineering Contradiction:
Improveelectrical connection stabilityVSAvoidconductor damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent resolves this contradiction by applying local quality through spatially differentiated serration depths. Deeper serrations are concentrated at the leading end where oxide film removal is most critical for electrical connection, while shallower serrations at the trailing end reduce mechanical damage to the conductor. This localized approach ensures effective oxide removal where needed while minimizing harm elsewhere.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the conductor crimp unit into distinct functional zones: a leading end with deeper serrations for oxide film removal and electrical connection, and a trailing end with shallower serrations for mechanical support with reduced damage. This segmentation allows each zone to perform its specific function optimally without compromising the other.

Inventive Principle:
Principle #1Segmentation

3Strength

If stronger crimping force is applied to reduce swaging variation, then mechanical connection strength is improved, but conductor damage increases

Engineering Contradiction:
Improvemechanical connection strengthVSAvoidconductor damage
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating shallower serrations at the trailing end of the conductor crimp unit, which reduces the crimping force required in that region. This localized reduction in serration depth minimizes conductor damage while the deeper serrations at the leading end ensure adequate mechanical interlocking and electrical connection, thereby maintaining overall mechanical strength without excessive force.

Inventive Principle:
Principle #3Local quality

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 reduces variability in swaging, stabilizes electrical connection resistance, and enhances mechanical connection strength by ensuring consistent contact and minimizing oxide film generation, while dispersing damage across element wires.

Implementation Method 1

when the conductor Wa of the electric wire W is crimped to the conductor crimp unit 112 of the crimp-style terminal 110 by swaging, and the element wire Wc of the conductor Wa is squeezed into the concave-grooved serration 118 while being deformed, an oxide film on a surface of the element wire Wc of the conductor Wa is torn staring from a serration edge 117

Methodology Applied
Scientific EffectMechanical deformation: Deformation

Implementation Method 2

a conductor crimp unit 112 which is almost U-shaped in section and crimped and connected to a conductor (a core wire) Wa formed by twisting together a plurality of element wires Wc of an electric wire W

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP2602876B1Crimp-style terminal
Publication Date: 2015.05.20 YAZAKI CORP
  • EP2602876B1 patent drawingFigure 1
  • EP2602876B1 patent drawingFigure 2~3
  • EP2602876B1 patent drawingFigure 4

AI summary

A crimp-style terminal (10) is provided with: a base plate (13); a conductor crimp unit (12) which is formed, to have a substantially U-shaped cross section, from a pair of conductor swage pieces (14) which extend to both sides of the base plate (13) and are swaged to encase conductors (Wa) of a wire (W), said wire being arranged on the inner surface of the base plate (13), and which is crimped and connected to the terminals of the conductors (Wa); and a plurality of serrations (16) which are on the inner surface of the conductor crimp unit (12) and which are formed from cylindrical concave sections having identical radii. Therein, the depth of the serrations (16) formed at the rear end-side inner surface of the conductor swage pieces (14) is shallower than that of the serrations (16) formed at the front end-side inner surface of the base plate (13).