Rotor Cooling Circuit Using Centrifugal Flow in Electric Motors

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Solution Overview

Problem

Existing cooling systems for high-power electric motors, such as those using external pumps or additional components, increase complexity and cost while failing to efficiently dissipate heat from critical components like stator windings and bearings.

Innovation Solution

A cooling system for electric motors that utilizes a fluid-driven circuit integrated within the rotor and stator, utilizing spiral ribs and grooves to facilitate heat dissipation without external pumps, leveraging the motor's rotation to circulate cooling fluid.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If external pumps or additional components are used for cooling, then cooling effectiveness is improved, but device complexity and manufacturing costs increase

Engineering Contradiction:
Improvecooling effectivenessVSAvoidsystem complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling circuit is merged with the rotor structure itself. The rotor body incorporates cooling channels, cooling ribs, and cooling cavities that form an integrated cooling system, eliminating the need for separate external pumping devices and additional cooling components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rotor serves dual functions: it performs its primary rotational function while simultaneously serving as the cooling system. The rotor structure itself conducts heat away from critical components through its integrated cooling features, making the system self-cooling without external assistance.

Inventive Principle:
Principle #25Self-service

2Temperature

If external pumps or additional components are used for cooling, then cooling effectiveness is improved, but manufacturing costs increase

Engineering Contradiction:
Improvecooling effectivenessVSAvoidmanufacturing cost
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The cooling circuit is merged with the rotor structure itself. The rotor body incorporates cooling channels, cooling ribs, and cooling cavities that form an integrated cooling system, eliminating the need for separate external pumping devices and additional cooling components.

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

Provides efficient and cost-effective cooling without external components, simplifying manufacturing and maintenance, while effectively dissipating heat from stator windings and bearings.

Implementation Method 1

a cooling circuit having a first part for transporting cooling fluid on and/or along the circumferential surface of the rotor from the first side to the second side and a second part for transporting the cooling fluid back to the first side

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the second part being located at least partially inside the housing and having a larger distance to the rotation axis than the first part

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP4679683A1Cooling system for an electric device and electric motor with the cooling system
Publication Date: 2026.01.14 KB INTELLECTUAL PROPERTY GMBH & CO KG
  • EP4679683A1 patent drawingFigure 1
  • EP4679683A1 patent drawingFigure 2
  • EP4679683A1 patent drawingFigure 3

AI summary

The present invention refers to a cooling system (100) for an electric device, in particular an electric motor, comprising a housing (110), a rotor (130) enclosed in the housing (120) and a cooling circuit (160) having a first part (162) for transporting cooling fluid on the circumferential surface (140) of the rotor (130) from the first side (136) to the second side (138) and a second part (164) for transporting the cooling fluid back to the first side (136) or vice versa, the second part (164) being located at least partially inside the housing (120) and having a larger distance to the rotation axis X than the first part (162). Further, the present invention refers to an electric motor (110).