Segmented Stator Ring Coating to Minimize Magnetic Resistance

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Solution Overview

Problem

Air gaps can occur between tangentially adjacent stator ring segments in electrical machines, increasing magnetic resistance.

Innovation Solution

Apply a radially inward pressing force to stator ring segments using a pressing device, followed by an outer coating to form a closed outer shell layer that maintains the pressing force after the device is stopped, minimizing magnetic resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If stator ring segments are placed together to form a stator ring, then the stator can be assembled from separate segments, but air gaps occur between adjacent segments which increases magnetic resistance

Engineering Contradiction:
Improvestator assembly from segmentsVSAvoidmagnetic resistance between segments
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

A pressing device is introduced as an intermediary tool to apply radial pressing force on the stator ring segments during coating application. This pressing device acts as a mediator between the coating process and the segments, ensuring continuous tangential pressing to eliminate air gaps and reduce magnetic resistance while maintaining the segmented assembly advantage

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If pressing force is applied continuously to stator ring segments, then contact between segments is maintained and magnetic resistance is reduced, but the complexity of the manufacturing process increases

Engineering Contradiction:
Improvecontact between segmentsVSAvoidpressing force application system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pressing force is applied preliminarily during the coating application process rather than as a separate continuous operation. The pressing device is integrated into the coating process, applying force before the outer coating is fully formed, allowing the coating itself to subsequently maintain the pressing force and eliminate the need for continuous external pressing mechanisms

Inventive Principle:
Principle #10Preliminary action

3Duration of action of stationary object

If outer coating is applied to stator ring segments while pressing force is applied, then the coating helps maintain pressing force after application, but the manufacturing process requires coordination of multiple operations

Engineering Contradiction:
Improvepressing force maintenanceVSAvoidcoating and pressing coordination
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The pressing operation and coating application are merged into a single integrated process step. The pressing device and coating application device work simultaneously, with the pressing force applied during coating rather than as separate sequential operations. This merging allows the outer coating to be formed under pressing conditions, enabling it to maintain the pressing force after application without requiring complex coordination between separate processes

Inventive Principle:
Principle #5Merging (Combining)

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 outer coating ensures continuous tangential pressing of stator ring segments, reducing magnetic resistance and maintaining contact integrity.

Implementation Method 1

a pressing device is used to generate a radially inwardly acting pressing force, by means of which the stator ring segments are tangentially pressed against one another

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

The outer coating is produced by cold spraying, flame spraying, a thermal spraying process for metallic materials or by deposition welding

Methodology Applied
Scientific EffectCold spraying: Cold-forming

Implementation Method 3

The outer coating is produced by cold spraying, flame spraying, a thermal spraying process for metallic materials or by deposition welding

Methodology Applied
Scientific EffectThermal spraying: Plasma Spray

Implementation Method 4

The elasticity coefficient of the layer material of the sheath layer preferably corresponds at least approximately to the elasticity coefficient of a housing of the electrical machine into which the stator is inserted

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4118731B1Method for manufacturing of an electrical machine
Publication Date: 2025.09.03 SIEMENS MOBILITY GMBH
  • EP4118731B1 patent drawingFigure 1
  • EP4118731B1 patent drawingFigure 2
  • EP4118731B1 patent drawingFigure 3

AI summary

The invention relates, inter alia, to a method for producing an electric machine (50), in which method, inter alia, stator ring segments (10) are placed next to one another to form a stator ring (20) and are then connected to one another. According to the invention, with this variant of the invention, after the stator ring (20) has been formed, a pressing force (F) acting radially inwards is generated by means of a pressing device, as a result of which pressing force the stator ring segments (10) are pressed tangentially against one another, and in the state in which they are pressed against one another, an outer coating is applied to radially external outer surfaces (13) of the stator ring segments (10), said coating forming a closed outer cover layer (21) on the stator ring (20).