Stator Cooling via Offset Slot Laminations

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Solution Overview

Problem

Existing electric machines with slotted stators require complex cooling arrangements, such as fluid circulation channels or external fins, leading to increased size, cost, and complexity.

Innovation Solution

A stator design without a tubular support, featuring a stack of laminations with angularly offset pairs of notches, incorporating cooling means like external radial projections that act as fins, allowing for heat exchange without additional structural components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If cooling fluid circulation channels are used between the tubular stator support and outer envelope, then heat evacuation is achieved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improveheat evacuationVSAvoidcooling arrangement complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The invention extracts the cooling function from the complex fluid circulation system and implements it directly in the stator laminations through simple through-holes and radial projections, eliminating the need for elaborate cooling channels and fluid circulation infrastructure

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The stator laminations perform their own cooling function through integrated through-holes and radial projections that enable direct heat transfer to cooling fluid, making the structure self-cooling without requiring separate dedicated cooling subsystems

Inventive Principle:
Principle #25Self-service

2Temperature

If external cooling fins are arranged on the tubular stator support, then heat evacuation by conduction and convection is improved, but device size and manufacturing complexity increase

Engineering Contradiction:
Improveheat evacuation efficiencyVSAvoidstator support size
Core Design Contradiction:
TemperatureVSVolume of stationary object

Solution Approach 1:

The invention merges the cooling fin function directly into the stator lamination structure through radial projections, combining the stator body and cooling fins into a single integrated component, thereby eliminating additional volume from separate fin structures

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cooling function is moved from external three-dimensional fin structures to two-dimensional radial projections on the stator laminations, reducing overall device volume while maintaining effective heat transfer surface area

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Temperature

If a tubular stator support with cooling channels is used, then cooling function is achieved, but manufacturing cost and complexity increase

Engineering Contradiction:
Improvewinding coolingVSAvoidstator assembly manufacturing
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The invention extracts the cooling function from the complex tubular support structure and implements it through simple through-holes in the stator laminations, dramatically simplifying manufacturing while achieving the same cooling objective

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses identical stator laminations with standardized through-hole patterns that can be mass-produced and stacked, replacing the custom-molded complex tubular support structure with simple, repeatable components

Inventive Principle:
Principle #26Copying

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 simplifies the cooling process, reduces size and cost, and enhances heat evacuation efficiency by optimizing heat exchange surfaces with the environment.

Implementation Method 1

The fluid which circulates in these channels captures the calories coming from the windings to evacuate them outside the machine and thus ensure the cooling of these windings

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

the laminations comprise cooling means for the stator and in that the laminations carry a bore in the solid portion between two pairs of notches and a hollow portion between the next two pairs of notches

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3304698B1Rotating electrical machine comprising a cooled slotted stator, in particular an electric motor
Publication Date: 2019.10.16 IFP ENERGIES NOUVELLES
  • EP3304698B1 patent drawingFigure 1~2
  • EP3304698B1 patent drawingFigure 3~4

AI summary

The invention relates to an electrical machine including a rotor (10) and a stator (12) comprising a stack of steel laminations (22) in order to form a stator body (26) with at least two pairs (44) of slots (32) for receiving magnetic flux generators (34) through which an electrical current flows, said pairs of slots being offset angularly from one another by an angle (α). According to the invention, the steel laminations comprise means (60) for cooling the stator.