Laser Welding Paths for Stator Conductor End Gaps

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Solution Overview

Problem

Existing methods for laser welding conductor wires in dynamo electric machines face challenges such as clearance issues due to insulating film stripping and inefficiencies in connecting conductor ends, leading to unreliable and time-consuming connections.

Innovation Solution

A method and apparatus for laser welding conductor wires that involves arranging the conductor wires in slots of a core, applying a laser beam in substantially closed paths within the end surfaces to form molten pools, and connecting these pools with a path that fills the gap between the wires, ensuring a reliable and efficient connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the insulating film is stripped from the ends of pin conductors to enable laser welding, then the laser beam can effectively weld the conductor ends, but a clearance appears between adjacent side surfaces of the conductors

Engineering Contradiction:
Improvewelding reliabilityVSAvoidalignment precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent introduces a filler material as an intermediary substance that fills the clearance between conductor side surfaces. This mediator allows the laser welding process to bridge the gap created by insulating film removal, enabling reliable weld formation despite the misalignment between adjacent conductor surfaces.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the laser beam is applied in a straight path between conductor ends, then the welding process is simple and fast, but the clearance between conductors cannot be filled effectively

Engineering Contradiction:
Improvewelding speedVSAvoidconnection reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent segments the laser beam path into multiple sections: a first portion applied to the first conductor end and a second portion applied to the second conductor end. This segmentation allows each laser path to independently form molten pools that can bridge the clearance gap, ensuring reliable connection while maintaining efficient welding speed through optimized path configuration.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If conductor ends are sharpened for easier slot insertion, then insertion is facilitated, but the end surfaces are no longer flat causing non-homogenous power distribution during laser welding

Engineering Contradiction:
Improveinsertion easeVSAvoidpower distribution uniformity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies local quality by concentrating laser energy at specific locations (the ends of conductors) rather than requiring uniform power distribution across the entire end surface. The segmented laser paths focus energy to create localized molten pools that bridge the clearance, accommodating the non-flat geometry of sharpened conductor ends while maintaining welding effectiveness.

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 approach allows for a fast and reliable connection of conductor wire ends, ensuring high precision and minimizing material waste, while maintaining the advantages of laser beam welding such as low cycle times and automation.

Implementation Method 1

A laser beam is applied to a first end surface of a first conductor wire and a second end surface of a second conductor wire to weld together the first end of the first conductor wire and the second end of the second conductor wire

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

applying a laser beam in substantially closed paths within the end surfaces to form molten pools

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

The first and the second molten pool are connected to one another by applying the laser beam in a path from the first molten pool to the second end surface

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 4

Due to gravity, the melt may bridge a gap between the conductor ends

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 5

applying a laser beam in substantially closed paths within the end surfaces to form molten pools

Methodology Applied
Scientific EffectLaser beam scanning: Laser

Data Source

PatentEP4268358B1Method and device for laser welding conductor wires
Publication Date: 2025.05.14 ATOP SPA
  • EP4268358B1 patent drawingFigure 1
  • EP4268358B1 patent drawingFigure 2
  • EP4268358B1 patent drawingFigure 3

AI summary

The present invention relates to a method for laser welding conductor wires (5, 7), in particular conductor wires (5, 7) arranged in slots (2) of a core (3) of a dynamo electric machine, such as a stator core, to form a winding and a device (35) for laser welding conductor wires (5, 7). A first end (4) of a first conductor wire (5) and a second end (6) of a second conductor wire (7) are arranged adjacent to each other. A laser beam is applied to a first end surface (8) of the first conductor wire (5) and a second end surface (10) of the second conductor wire (7) to weld together the first end (4) of the first conductor wire (5) and the second end (6) of the second conductor wire (7). The first end surface (8) and the second end surface (10) point upwards, preferable the first end surface (8) and the second end surface (10) are axial end surfaces. A laser beam (31) is applied in a first substantially closed path (21) within the first end surface (8) to form a first molten pool (25). The laser beam (31) is applied in a second substantially closed path (22) within the second end surface (10) to form a second molten pool (26). The laser beam (31) is applied in a third substantially closed path (23) to the first end surface (8) and to the second end surface (10) connecting the first and second molten pool.