Integrated Liquid-Cooled Housing for Electrical Machines

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Solution Overview

Problem

Existing liquid-cooled housings for electrical machines face challenges in effective heat transfer due to the use of negative molds and additional cooling tubes, which complicate manufacturing and impair heat transfer efficiency.

Innovation Solution

A liquid-cooled housing design where the peripheral jacket and end shield are connected in one piece, eliminating the need for additional cooling tubes by integrating channels directly into the housing structure, allowing for improved heat transfer and liquid-tight material transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional cooling tubes are introduced into the mold before casting or sintering, then liquid cooling is achieved, but heat transfer is impaired due to small cross-section and cavities between tubes and material

Engineering Contradiction:
Improveliquid cooling capabilityVSAvoidheat transfer efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The cooling channels are merged with the housing structure itself, eliminating the need for separate cooling tubes. The channels are formed directly in the housing material through the negative mold, creating an integrated structure where the housing walls form the channel boundaries. This eliminates the tube-wall heat transfer barrier and cavity issues associated with embedded tubes.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cooling function is extracted from separate tube components and integrated into the housing structure. By forming channels directly in the housing material rather than embedding tubes, the design removes the intermediate tube wall that impairs heat transfer, allowing direct thermal contact between the housing and cooling liquid.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of manufacture

If negative molds are used for casting or sintering the housing, then the housing can be produced, but manufacturing complexity increases and requires specialist companies and trained personnel

Engineering Contradiction:
Improvehousing production capabilityVSAvoidmanufacturing process complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The negative mold is designed with pre-formed channel cavities that directly create the cooling channels during the casting or sintering process. This preliminary design of the mold eliminates the need for subsequent tube embedding or channel creation steps, simplifying the overall manufacturing process while maintaining the ability to produce complex cooled housings.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If the end shield is screwed onto the front of the tube with reinforcement strips, then assembly is simplified and decentralized production is enabled, but liquid-tightness in the transition area is compromised

Engineering Contradiction:
Improvedecentralized production capabilityVSAvoidliquid-tightness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The end shield and peripheral jacket are merged into a single integral component through the negative mold forming process. The mold creates a continuous structure where the transition area between the end shield and jacket is formed as one piece, eliminating the screwed connection and associated leakage risks while maintaining the benefits of standardized production.

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 design enhances heat transfer efficiency by eliminating the need for additional cooling tubes, allowing cooling liquid to flow directly between the peripheral jacket and end shield, thereby improving thermal management without the complexity of negative molds.

Implementation Method 1

heat transfer to the cooling liquid

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

cooling liquid flows through the ring-shaped cooling channel

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2479875B1Liquid cooled housing with bearing shield for electrical machine
Publication Date: 2018.07.04 BOMBARDIER TRANSPORTATION GMBH
  • EP2479875B1 patent drawingFigure 1
  • EP2479875B1 patent drawingFigure 2
  • EP2479875B1 patent drawingFigure 3

AI summary

The invention relates to a housing (1) for an electric machine, wherein the housing (1) comprises: - a circumferential shell (2) which surrounds an interior housing space (I) for receiving the electric machine in a circumferential direction, - a bearing plate (4) for supporting a rotor shaft of the machine, - channels (10, 20) for conveying coolant, wherein - the circumferential shell (2) and the bearing plate (4) are integrally connected, - at least one channel (10, 20) for conveying coolant is provided on and/or in the circumferential shell (2) and on and/or in the bearing plate (4), and - at least one fluid transfer (52) from a channel (10) of the circumferential shell (2) to a channel (20) of the bearing plate (4) and/or vice versa is formed in the transition area of ​​the circumferential shell (2) to the bearing plate (4).