Crimping Tool with Differential Grooves for Aluminum Cable Contacts

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Solution Overview

Problem

The replacement of copper cables with aluminum cables in vehicles leads to reduced electrical conduction due to the oxide layer on aluminum, and increasing compression to improve conductivity compromises the mechanical strength of the cable.

Innovation Solution

A crimping tool with a punch and anvil design featuring grooves and surfaces of varying depths and heights to create distinct crimping elements, allowing for differential compression ratios between mechanical retention and electrical conduction portions, forming a descending and rising step to enhance conductivity while maintaining mechanical integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the compression ratio of the cable in the crimping zone is increased to break the oxide layer and improve electrical conduction, then electrical conductivity is improved, but the mechanical strength of the cable in the compressed zone is reduced

Engineering Contradiction:
Improveelectrical conductivityVSAvoidmechanical strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The crimping zone is divided into two distinct portions: a mechanical retention portion with lower compression ratio to preserve cable strength, and an electrical conduction portion with higher compression ratio to break the oxide layer and improve conductivity. This segmentation allows each portion to be optimized for its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different compression ratios are applied to different zones within the crimping area. The mechanical retention portion receives lighter compression to maintain structural integrity, while the electrical conduction portion receives heavier compression to ensure good electrical contact by breaking the oxide layer. This local differentiation of compression quality resolves the contradiction between mechanical strength and electrical conductivity.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If a single crimping height is used for the entire crimping zone, then the manufacturing process is simple, but it is impossible to simultaneously optimize both mechanical retention and electrical conduction

Engineering Contradiction:
Improvecrimping process simplicityVSAvoidsimultaneous optimization of mechanical and electrical properties
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The punch element is segmented into two distinct crimping portions with different heights: a first crimping portion for the mechanical retention zone and a second crimping portion for the electrical conduction zone. This segmentation enables differential compression ratios while maintaining a single integrated punch component, balancing manufacturing simplicity with performance optimization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The crimping tool uses a punch element with varying heights to apply different compression parameters to different zones. The first crimping portion has a greater height to apply lower compression, while the second crimping portion has a lesser height to apply higher compression. This parameter variation within a single component allows simultaneous optimization of mechanical and electrical properties without complicating the manufacturing process.

Inventive Principle:
Principle #35Parameter changes

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 achieves improved electrical conductivity and mechanical retention by optimizing compression ratios, reducing the degradation of properties over time and preventing galvanic corrosion.

Implementation Method 1

the compression ratio of the cable in the crimping zone can be increased

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

the strands of the cable are less compressed. The integrity of their mechanical properties is therefore essentially preserved

Methodology Applied
Scientific EffectPlasticity: Plasticity

Implementation Method 3

the aluminum being covered with an oxide layer, the electric conduction at the level of the contact areas between an aluminum cable and a copper contact can be reduced

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 4

the electric conduction at the level of the contact areas between an aluminum cable and a copper contact can be reduced

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP3488504B1Crimping tool, crimping process and contact obtained with the tool
Publication Date: 2021.06.16 APTIV TECHNOLOGIES LTD
  • EP3488504B1 patent drawingFigure 1
  • EP3488504B1 patent drawingFigure 2
  • EP3488504B1 patent drawingFigure 3~4

AI summary

A crimping tool (40) comprising a crimping section (14) extending in a longitudinal direction (L) comprising a crimping punch part (60) and a crimping anvil part (50), the punch part (60) being provided with a first punch element and a second punch element (62, 64) adjacent to the first element; the anvil part (50) being provided with a first and a second anvil element (51, 53) for crimping; the first and the second punch element (62, 64) respectively comprising a first and a second groove (73, 74), the first punch element (62) having a groove depth (P1) that is deeper than the groove depth (P2) of the second punch element (64), so as to form a downwards punch step (75) from the first groove (73) to the second groove (74); the first and the second anvil element (51, 53) respectively comprising a first and a second crimping surface (56, 58); the second crimping surface (58) is raised relative to the first crimping surface (56) so as to form an upwards anvil step (90).