Contact Terminal With Meandering Spring For Stable Force

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Solution Overview

Problem

Contact terminals in automotive applications face reliability issues due to uneven force distribution and increased thermal stress, which can lead to reduced performance at high temperatures, especially above 150 °C, and are prone to manufacturing deviations.

Innovation Solution

A contact terminal design featuring a base part with contact tongues and a sleeve with a meandering zigzag-shaped flexible support structure, where the spring element provides a time-independent contact force, separating the functions of electrical/thermal contact and force application, ensuring even force distribution across lamellas and compensating for manufacturing deviations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a resilient contact element is used to provide contact normal force, then the contact terminal can maintain contact force, but the contact force becomes dependent on operation time and temperature due to thermal stress

Engineering Contradiction:
Improvecontact normal forceVSAvoidcontact force stability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The contact terminal is divided into separate functional parts: the base part with contact tongues for electrical connection and the sleeve with spring element for force application. This segmentation allows each part to be optimized for its specific function, with the spring element providing stable force independent of thermal stress affecting the electrical contacts.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs a meandering zigzag-shaped flexible support structure that changes its geometric parameters under thermal stress. The zigzag configuration allows the structure to expand and contract in a controlled manner, maintaining contact force stability despite temperature variations up to 200°C.

Inventive Principle:
Principle #35Parameter changes

2Strength

If an utterly covering hood is used to protect the inner electrical unit, then protection is improved, but the contact force distribution becomes uneven across contact points

Engineering Contradiction:
Improveprotection of electrical unitVSAvoidforce distribution uniformity
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The spring element is designed with localized contact points that distribute force evenly across individual contact tongues. The meandering zigzag structure creates multiple discrete contact zones, ensuring each contact point receives appropriate force independently, rather than applying uniform pressure across the entire hood structure.

Inventive Principle:
Principle #3Local quality

3Device complexity

If multiple lamellas share a common support, then device complexity is reduced, but the normal force distribution becomes uneven and contact force behavior becomes interdependent

Engineering Contradiction:
Improvesupport structure complexityVSAvoidindependent contact force behavior
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

Each contact tongue is equipped with its own dedicated spring element and flexible support structure. This segmentation ensures that the contact force behavior of each lamella is independent, allowing individual optimization and compensation for manufacturing deviations without affecting other contact points.

Inventive Principle:
Principle #1Segmentation

4Reliability

If the contact tongue is optimized for electrical contact, then electrical performance is improved, but the contact force application becomes compromised

Engineering Contradiction:
Improveelectrical contact performanceVSAvoidcontact force application
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent separates the electrical contact function (performed by the base part and contact tongues) from the force application function (performed by the sleeve and spring element). This allows the contact tongues to be optimized for electrical and thermal contact without compromising mechanical force application, as these functions are performed by distinct structural elements.

Inventive Principle:
Principle #1Segmentation

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 provides a robust, temperature-independent contact force up to 200 °C, ensuring reliable operation and optimal contact performance despite manufacturing variations, with the flexible support structure allowing for precise force application and compensation of misalignments.

Implementation Method 1

The at least one spring element is adapted to contact the plurality of contact tongues on a backside opposite to the contact surfaces side

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

Terminals in Automotive applications provide a contact normal force to the electrical contacts by employing resilient contact elements

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

enables an operation at temperatures beyond 150 °C without a significant change of its contact force

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 4

The flexible support structure is meandering from the first arm to the second arm. The flexible support structure extends in a zigzag shape perpendicular to the mating axis

Methodology Applied
Scientific EffectFlexible support structure: Elasticity

Data Source

PatentEP3392975B1Contact terminal assembled from at least two parts
Publication Date: 2020.02.19 APTIV TECHNOLOGIES LTD
  • EP3392975B1 patent drawingFigure 1~2
  • EP3392975B1 patent drawingFigure 3~4
  • EP3392975B1 patent drawingFigure 5~6

AI summary

A contact terminal (1) assembled from at least two parts, comprising a base part (10), having a plurality of contact tongues (12), aligned along a mating axis (X), adapted to contact a male connector pin (100) by contact surfaces (13) on the plurality of contact tongues (12); a sleeve (40) adapted to be arranged at least partially over the base part (10), the sleeve (40) having at least one spring element (60), wherein the at least one spring element (60) is adapted to contact the plurality of contact tongues (12) on a side opposite to the contact surfaces side (4) ; wherein the at least one spring element (60) comprises a first arm (63) and a second arm (64) and a flexible support structure (65) in between, wherein the first arm and the second arm protrude from the sleeve , along the mating axis inside the sleeve, wherein the flexible support structure (65) is meandering from the first arm to the second arm.