Longitudinal Ultrasonic Welding for Stranded Conductor Joints

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Solution Overview

Problem

Existing methods for connecting stranded conductors to connection parts, such as rotary friction welding and torsional ultrasonic welding, face issues like asymmetry leading to imbalances, high costs, complex system technology, limited applicability to larger cross-sections, and difficulty in achieving precise axial angles, resulting in inefficient and potentially damaging connections with poor electrical conductivity.

Innovation Solution

The method employs longitudinal ultrasonic welding to create a material connection between a support sleeve and a stranded conductor, allowing for precise positioning and absorption of compression forces, breaking down non-conductive oxide layers, and enabling a gas-tight, corrosion-resistant bond with flexible geometric configurations, using a clamping device that presses and welds the support sleeve to the conductor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If rotary friction welding is used to connect stranded conductors to connection parts, then a material-locking joint is created, but the joining partners must be rotationally symmetrical and the process becomes complex and costly

Engineering Contradiction:

Improvejoint strengthVSAvoidprocess complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent replaces rotary friction welding with a pressing operation followed by longitudinal ultrasonic welding. This substitution eliminates the requirement for rotational symmetry and simplifies the joining system while maintaining strong material-locking joints between the support sleeve and connection part.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Force

If rotary friction welding is used, then compression forces are absorbed, but the support sleeve must be dimensioned large resulting in long and stiff contact connection areas

Engineering Contradiction:

Improvecompression force absorptionVSAvoidcontact connection area length

Core Design Contradiction:

ForceVSLength of moving object

Solution Approach 1:

The patent changes the joining method from rotary friction welding to pressing combined with longitudinal ultrasonic welding. This parameter change allows the support sleeve to be dimensioned more compactly while still absorbing compression forces effectively, resulting in shorter and more flexible contact connection areas.

Inventive Principle:

Principle #35Parameter changes

3Strength

If torsional ultrasonic welding is used to join connection parts, then joining energy is introduced, but the connection parts often tear and the system technology becomes very complex and error-prone

Engineering Contradiction:

Improvejoint strengthVSAvoidconnection reliability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent inverts the joining sequence: instead of directly ultrasonic welding the connection part to the stranded conductor (which causes tearing), it first presses the support sleeve onto the conductor to create a reinforced structure, then performs ultrasonic welding. This reversed approach distributes stresses more evenly and prevents tearing while simplifying the system.

Inventive Principle:

Principle #13The other way round (Inversion)

4Strength

If rotary friction welding is used, then joining is achieved, but precise axial angle positioning between joining partners cannot be set

Engineering Contradiction:

Improvejoint strengthVSAvoidaxial angle precision

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The patent replaces rotary friction welding with a pressing operation followed by longitudinal ultrasonic welding. This substitution enables precise axial angle positioning during the pressing step, allowing accurate alignment between the support sleeve and connection part before welding, thereby achieving manufacturing precision that was not possible with rotary friction welding.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 approach enables safe, damage-free connections with high electrical conductivity, reduced complexity, and cost-effective industrial production, allowing for flexible geometric designs and precise alignment, even with non-rotationally symmetrical shapes, while avoiding cavities that could lead to corrosion.

Implementation Method 1

a welding surface of an ultrasonic sonotrode is placed on the connection part and that the welding surface is excited by means of a converter with an ultrasonic vibration in such a way that the welding surface oscillates longitudinally and the welding energy is introduced into the connection part and the stranded conductor

Methodology Applied

Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Data Source

PatentEP3555964B1Joining a connecting element to a stranded conductor

Publication Date: 2021.10.27 AUTO KABEL MANAGEMENT GMBH

Figure 1a~1b
Figure 2a~2b
Figure 3a~3b

AI summary

The invention relates to the connection of a stranded conductor 2 to a connection part 10, via an end 4 of said stranded conductor 2 and a connection part 10 which is bonded with said end 4 of the stranded conductor 4, wherein an end face of the end of the stranded conductor 2 is welded to said connection part 10 ultrasonically. A particularly good weld seam can be achieved by welding the end of the stranded conductor 4 to a sleeve 8, initially by means of ultrasonic welding.