Laminated Core Cooling via Segmented Offset Channels

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Solution Overview

Problem

Laminated cores in electrical machines heat up due to electrical losses and magnetic eddy fields, particularly in areas without cooling channels, such as the tooth areas, leading to inefficient cooling.

Innovation Solution

The laminated core design incorporates tangentially offset sheet metal segments with recesses forming inlet, inter-tooth, and return channels that distribute and collect a cooling medium, allowing for efficient heat absorption from the tooth areas, with channels arranged to minimize mechanical stress and facilitate easy access for cooling medium flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If cooling channels are provided in the laminated core, then cooling capacity is improved, but the tooth areas (where coils are located and heat is generated) are not adequately cooled because they are not interspersed with cooling channels

Engineering Contradiction:
Improvecooling capacityVSAvoidcooling effectiveness in tooth areas
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The laminated core is divided into multiple individual laminations, each with its own cooling channels. This segmentation allows cooling channels to be distributed throughout the entire core structure, including the tooth areas, enabling effective cooling of heat-generating regions while maintaining overall cooling capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Cooling channels are specifically positioned within the tooth areas of individual laminations where heat is generated by the coils. This local placement ensures that cooling capacity is concentrated in the regions that need it most, improving cooling effectiveness in the previously problematic tooth areas.

Inventive Principle:
Principle #3Local quality

2Temperature

If multiple laminations are used with individual cooling channels, then cooling capacity is improved, but the structural complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvecooling capacityVSAvoidlaminated core structure
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The laminated core is divided into multiple individual laminations, each with its own cooling channels. This segmentation allows cooling channels to be distributed throughout the entire core structure, including the tooth areas, enabling effective cooling of heat-generating regions while maintaining overall cooling capacity.

Inventive Principle:
Principle #1Segmentation

3Temperature

If cooling channels are added to cool the tooth areas, then cooling effectiveness is improved, but mechanical strength may be reduced due to material removal

Engineering Contradiction:
Improvecooling effectivenessVSAvoidmechanical strength of laminated core
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The laminated core is divided into multiple individual laminations, each with its own cooling channels. This segmentation allows cooling channels to be distributed throughout the entire core structure, including the tooth areas, enabling effective cooling of heat-generating regions while maintaining overall cooling capacity.

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

This design enables quick and uniform cooling of the laminated core, reducing thermal conductivity limitations and enhancing the performance and stability of electrical machines by effectively transferring heat away from the tooth areas.

Implementation Method 1

The heat generated is absorbed through the cooling channels

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a cooling medium running through the cooling ducts

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3157138B1Method for cooling a stack of metal sheets, stack of metal sheets, rotor, stator and electric machine
Publication Date: 2018.07.25 SIEMENS AG
  • EP3157138B1 patent drawingFigure 1
  • EP3157138B1 patent drawingFigure 2
  • EP3157138B1 patent drawingFigure 3

AI summary

The invention relates to a laminated core (100), a rotor, a stator, an electric machine, and a method for cooling a laminated core 100. The laminated core (100) consists of sheets (1) or sheet segments (1a). The sheets (1) or the sheet segments (1a) have recesses (3a, 5a, 11a, 12a, 13a), wherein the recesses (3a, 5a, 11a, 12a, 13a) form channels for the cooling medium (K) after the sheets (1) or the sheet segments (1a) are assembled to form the laminated core (100). Characteristic of the channels (3, 5, 11, 12, 13) is that in a yoke area (9) of the lamination stack (100) inlet channels (3) and return channels (5) are formed from the recesses (3a, 5a, 11a, 12a, 13a), that further channels (11, 12, 13) run in parallel to the inlet and return channels (3, 5) and that the further channels (11, 12, 13) are located in the area of ​​the teeth of the lamination stack (100).The invention allows the interior of the sheet metal stack (100) to be cooled directly, and the production costs can be greatly reduced by using identical sheet metal segments (1, 1a) in a rotationally offset manner.