Rotating Electrical Machine Cooling Fins Noise Reduction

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Solution Overview

Problem

Rotating electrical machines face challenges in heat dissipation and noise reduction, particularly when used under direct sunlight, due to inefficient cooling of power conversion devices and noise generation from inverters.

Innovation Solution

A rotating electrical machine design featuring a cylindrical cover with integrated cooling fins and a centrifugal fan, along with a covering member made of sound-absorbing and vibration-damping materials, which enhances heat dissipation and noise suppression by distributing heat sources and using elongated cooling fins for efficient air flow and ventilation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If an inverter is mounted inside cylindrical casings stacked on a rotating shaft, then the rotating electrical machine can be compactly configured, but heat from the inverter cannot be dissipated to outside in a reliable manner

Engineering Contradiction:
Improvecompact configurationVSAvoidheat dissipation
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The inverter is nested within the cylindrical casing structure, with the power conversion device housed inside the casing that is stacked on the rotating shaft. This nested configuration achieves compact integration while the casing includes through-holes for heat dissipation, resolving the contradiction between compactness and thermal management.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Temperature

If part of air flow from the cooling fan is introduced into cooling fins of the inverter, then cooling efficiency is improved, but it remains difficult to dissipate heat of the inverter to outside reliably

Engineering Contradiction:
Improvecooling efficiencyVSAvoidheat dissipation reliability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The cooling system is segmented into multiple independent pathways: the cooling fan provides air flow to cooling fins on the stator, while separate through-holes in the cylindrical casing enable direct heat dissipation from the inverter to the external environment. This segmentation ensures reliable heat dissipation without compromising cooling efficiency.

Inventive Principle:
Principle #1Segmentation

3Object-generated harmful factors

If soundproofing means is enhanced to reduce noise from the inverter, then noise generation is suppressed, but heat dissipation effect is reduced

Engineering Contradiction:
Improvenoise reductionVSAvoidheat dissipation
Core Design Contradiction:
Object-generated harmful factorsVSTemperature

Solution Approach 1:

The casing structure is segmented to include dedicated soundproofing portions and dedicated through-holes for heat dissipation. The soundproofing material is selectively applied to specific regions (such as the end plates and portions of the casing) while leaving through-holes open for thermal ventilation, thus achieving both noise reduction and heat dissipation simultaneously.

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

The design effectively cools the machine by dissipating heat generated by power conversion devices and reduces noise levels, ensuring reliable operation under severe environments like direct sunlight without adverse effects on heat dissipation.

Implementation Method 1

the rotating electrical machine is provided with a cooling fan for cooling down the rotating electrical machine by performing heat exchange between air blown by a cooling fan and cold air supplied by cooling fins provided on a cover enclosing a stator

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

a covering member made of sound-absorbing and vibration-damping materials, which enhances heat dissipation and noise suppression

Methodology Applied
Scientific EffectAcoustic Absorption: Acoustic Absorption

Implementation Method 3

using elongated cooling fins for efficient air flow and ventilation

Methodology Applied
Scientific EffectHeat Exchanger: Heat Exchanger

Implementation Method 4

elongated cooling fins for efficient air flow and ventilation

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2549629B1Rotating electrical machine
Publication Date: 2019.05.15 HITACHI IND EQUIP SYST CO LTD
  • EP2549629B1 patent drawingFigure 1
  • EP2549629B1 patent drawingFigure 2
  • EP2549629B1 patent drawingFigure 3

AI summary

Provided is a rotating electrical machine which comprises a housing having a plurality of cooling fins formed on an outer circumference thereof, a stator fitted to the housing, a rotor fixed to a rotating shaft and configured to rotate by a rotating magnetic field generated by the stator, a cooling fan configured to rotate as the rotating shaft rotates, a cover disposed on the outer circumference of the housing, and a covering member disposed between the cover and the housing so as cover tips of the plurality of cooling fins and thereby form a space between the plurality of cooling fins. With this configuration, heat dissipation effect by sound-absorbing effect and a space formed by the covering member can be achieved and cooling by cooling air becomes possible.