Rotary Electric Machine Cooling Unit Placement

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Solution Overview

Problem

The complexity of connections between gas cooling units and circulation paths in rotary electric machines increases the size of the machine, reducing installation flexibility, especially when cooling units are placed on side surfaces, requiring a large installation area for optimal performance.

Innovation Solution

A rotary electric machine design with a gas cooling unit that includes intake and exhaust ports, a high and low temperature cooling gas flow path, and a heat insulating unit between the low temperature path and the casing, allowing the ventilation surface to be positioned above, below, or beside the casing, minimizing the volume of gas cooling units and preventing heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gas cooling units are distributed on both side surfaces of the rotary electric machine to maximize cooling performance, then cooling efficiency is improved, but the installation area required increases and installation flexibility is reduced

Engineering Contradiction:
Improvecooling efficiencyVSAvoidinstallation area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent positions the ventilation surface of the gas cooling unit above, below, or beside the side surface of the casing rather than directly on the side surface. This spatial repositioning allows the cooling unit to achieve effective cooling without projecting outward, thereby reducing the required installation area while maintaining cooling efficiency.

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

2Reliability

If multiple gas cooling units are distributed to optimize cooling performance, then cooling effectiveness is improved, but the connection between cooling units and circulation paths becomes more complicated

Engineering Contradiction:
Improvecooling effectivenessVSAvoidconnection complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates the high temperature cooling gas flow path and low temperature cooling gas flow path within a single gas cooling unit structure. The ventilation surface serves as a shared heat exchange component for both flow paths, simplifying the overall connection architecture between cooling units and circulation paths while maintaining effective cooling performance.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If gas cooling units are positioned to maximize cooling performance, then cooling capability is improved, but the outer dimensions of the rotary electric machine increase

Engineering Contradiction:
Improvecooling capabilityVSAvoidmachine volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent designs the gas cooling unit with nested flow paths where the low temperature cooling gas flow path is positioned close to the casing and the high temperature cooling gas flow path is positioned away from the casing. This nested arrangement allows both cooling functions to be integrated within a compact volume, minimizing the outer dimensions of the rotary electric machine while maintaining effective cooling capability.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 enhances cooling efficiency, reduces the number of gas cooling units needed, minimizes installation area, and increases installation flexibility by optimizing the placement of the gas cooling unit.

Implementation Method 1

a ventilation surface exchanging heat with the cooling gas at high temperature and cooling the cooling gas

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a heat insulating unit provided between the low temperature cooling gas flow path of the gas cooling unit and the casing, the heat insulating unit preventing transfer of heat between the low temperature cooling gas flow path and the casing

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3346588B1Rotary electric machine
Publication Date: 2021.05.05 MITSUBISHI ELECTRIC CORP
  • EP3346588B1 patent drawingFigure 1~2
  • EP3346588B1 patent drawingFigure 3~4
  • EP3346588B1 patent drawingFigure 5~6

AI summary

In a rotary electric machine having a cooling structure for cooling a stator and a rotor by circulating a cooling gas, a gas cooling unit is disposed above, below, or beside the side surface of a casing in which the stator and the rotor are accommodated and a heat insulating unit for preventing transfer of heat is provided between a low temperature cooling gas flow path in the gas cooling unit and the casing.