Air-Cooled Electric Machine Fan Integration in Drive-Side Coupling

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Solution Overview

Problem

Conventional air-cooled electrical machines have increased space requirements and impaired cooling effects due to the placement of fans on the non-drive side, leading to larger sizes and reduced power output.

Innovation Solution

The fan is rearranged to be on the drive side and integrated within the machine-side clutch, with guide elements and additional cooling ribs to enhance cooling efficiency, and optionally a second fan for the transmission side, all within a housing for protection and improved assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the fan is arranged on the non-drive side of the machine, then the cooling air can be directed through axially arranged cooling ducts, but the axial length of the drive is increased and the space requirement is increased

Engineering Contradiction:
Improvecooling effectVSAvoidaxial length
Core Design Contradiction:
TemperatureVSLength of moving object

Solution Approach 1:

The fan is inverted from its conventional position on the non-drive side to the drive side of the electrical machine. This inversion allows the fan to be integrated into the clutch assembly, eliminating the need for additional axial space while maintaining cooling functionality through the stator's axial cooling ducts

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of operation

If the coupling for detachable connection of the rotor shaft is arranged outside the housing, then the connection is accessible, but the axial overall length is increased

Engineering Contradiction:
Improveaccessibility of couplingVSAvoidaxial overall length
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

The coupling for detachable connection of the rotor shaft is merged with the housing structure, allowing the coupling to be accessible while eliminating the need for additional axial space that would be required if the coupling were positioned outside the housing

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

This configuration reduces the axial length and mass of the machine, enhances cooling on both sides, and allows for more compact, high-power designs suitable for applications like rail vehicles, while maintaining effective contamination protection and reduced assembly efforts.

Implementation Method 1

a fan on the non-drive side of the machine, which is non-rotatably connected to the rotor shaft in order to direct cooling air through axially arranged cooling ducts in the stator

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

to dissipate the heat generated

Methodology Applied
Scientific EffectHeat Dissipation: Convection

Data Source

PatentEP3200327B1Air-cooled electric machine
Publication Date: 2020.06.03 TRAKTIONSSYSTEME AUSTRIA GMBH
  • EP3200327B1 patent drawingFigure 1
  • EP3200327B1 patent drawingFigure 2
  • EP3200327B1 patent drawingFigure 3

AI summary

The invention relates to an air-cooled electric machine (1) with a rotor (3) non-rotatably connected to a rotor shaft (2), a stator (4) with axially arranged cooling channels (5), bearing shields (8, 9) arranged on the drive side (AS) and non-drive side (NAS) of the machine (1) containing the bearings (6, 7) for rotatably receiving the rotor shaft (2), a coupling (11) arranged at the drive-side end (10) of the shaft (2) with a machine-side coupling part (12) and a gearbox-side coupling part (13) for connection to a gearbox (14), and with a fan (15) connected to the rotor shaft (2) for guiding the cooling air through the axial cooling channels (5).To achieve a more compact design and improved cooling effect, the fan (15) is arranged on the drive side (AS) of the machine (1) and integrated into the coupling (11), so that the cooling air (L) can be guided from an air inlet (16) on the drive side (AS) through the axial cooling channels (5) to an air outlet (17) on the non-drive side (NAS).