Rotary Electric Machine Gas Cooler Upper Casing Layout

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Solution Overview

Problem

Conventional rotary electric machines require a wide installation area due to their large width, limiting their installation flexibility without compromising cooling performance for stator coil ends.

Innovation Solution

The rotary electric machine design incorporates gas coolers housed in the casing's upper portion near stator coil ends, with a modified gas circulation passage that allows cooling gas to flow efficiently through the machine, reducing the machine's width by positioning one gas cooler outside the casing above each stator coil end and using partition walls to ensure effective cooling gas passage without obstructing the flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If four gas coolers are provided at the side surface of the rotary electric machine, then cooling performance for stator coil ends is improved, but the installation area increases

Engineering Contradiction:
Improvecooling performanceVSAvoidinstallation area
Core Design Contradiction:
TemperatureVSArea of stationary object

Solution Approach 1:

The gas coolers are repositioned from the side surface to the upper surface of the casing, utilizing the vertical dimension instead of horizontal space. This dimensional shift allows the coolers to be arranged above the stator coil ends without increasing the machine's footprint area, thereby maintaining cooling performance while reducing installation area.

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

Solution Approach 2:

The gas coolers are housed within gas cooler chambers that are integrated into the casing structure. This nesting approach allows the coolers to be contained within the existing casing volume rather than requiring external side-mounted space, effectively utilizing internal volume to reduce external footprint.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Area of stationary object

If the entire rotary electric machine is made large in width direction, then space for gas coolers is increased, but the degree of freedom in installation becomes low

Engineering Contradiction:
Improvespace for gas coolersVSAvoiddegree of freedom in installation
Core Design Contradiction:
Area of stationary objectVSAdaptability or versatility

Solution Approach 1:

By moving gas coolers to the upper surface and utilizing vertical space, the invention eliminates the need to increase width, thereby maintaining installation flexibility and adaptability to various mounting configurations while still providing adequate space for gas cooler operation.

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

Solution Approach 2:

The gas circulation passage is designed with flexible routing that can adapt to the repositioned coolers, allowing the cooling system to maintain effectiveness regardless of the compact arrangement, thus preserving installation freedom.

Inventive Principle:
Principle #15Dynamics

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 decreases the installation area of the rotary electric machine while maintaining effective cooling performance for stator coil ends, enabling increased installation flexibility and potential energy savings and durability improvements.

Implementation Method 1

a gas cooler (14) housed in a gas cooler chamber (13) provided at an upper portion of a casing (2) in which both ends of a stator coil (6) are located

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a gas circulation passage is formed in which cooling gas circulates in the order of a space A provided at an intake side of a fan → a space B surrounding the fan → the gas cooler chamber (13) → the gas cooler (14)

Methodology Applied
Scientific EffectForced convection: Forced Convection

Data Source

PatentEP3223406B1Rotary electric machine
Publication Date: 2021.03.24 MITSUBISHI ELECTRIC CORP
  • EP3223406B1 patent drawingFigure 1
  • EP3223406B1 patent drawingFigure 2
  • EP3223406B1 patent drawingFigure 3

AI summary

Gas coolers (14) one of which is housed in a gas cooler chamber (13) provided at an upper portion of a casing (2) and installed near an opening (15) of the casing (2) above each stator coil end (7), are provided. A gas circulation passage is formed in which a cooling gas circulates through a space A provided at an intake side of each fan (12) → a space B surrounding the fan (12) → the gas cooler chamber (13) → the gas cooler (14) → a space C including the stator coil end (7) → a gap (11) between a rotor (4) and a stator (3) and gas passages formed in the rotor (4) and the stator (3) → a space D between an outer periphery of the stator (3) and the casing (2) → the space A.