Modular Electric Machine Frame with Axial Cooling Ducts

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Solution Overview

Problem

Traditional manufacturing methods for water-cooled frames of electric machines, such as casting and welded constructions, are costly and inefficient, especially for smaller machines, due to high manual work and tooling costs, making it difficult to produce frames of varying lengths and diameters efficiently.

Innovation Solution

A modular frame construction using extruded tubular profiles with arc-shaped inner surfaces and axial cooling ducts, where multiple modules are welded together to form a continuous circular frame, allowing for easy adjustment of length and diameter without the need for specific tooling for each size, and machining to achieve a desired circular opening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional casting or welded construction methods are used for water-cooled frames, then cooling functionality is achieved, but manufacturing cost and tooling costs increase significantly

Engineering Contradiction:
Improvemanufacturing costVSAvoidcooling functionality
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The frame is divided into multiple modular segments that can be produced separately using cost-effective extrusion processes. Each segment contains integrated cooling channels, and the segments are subsequently assembled to form the complete frame structure. This segmentation enables lower tooling costs while maintaining cooling functionality through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The frame structure is designed to serve multiple functions: structural support, liquid cooling conduit, and modular assembly unit. The extruded profile integrates both mechanical load-bearing capabilities and cooling fluid flow paths, eliminating the need for separate cooling system tooling and reducing overall manufacturing complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of manufacture

If traditional casting methods with embedded steel tubes are used, then cooling channels are formed, but manual work and tooling costs increase

Engineering Contradiction:
Improvetooling costVSAvoidmanual work
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

Cooling channels are pre-formed as integral parts of the extruded frame segments during the manufacturing process itself, rather than requiring subsequent manual embedding of steel tubes. The extrusion process creates the cooling fluid flow paths directly within the frame structure, eliminating time-consuming manual operations.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If extruded tubular profiles are used to eliminate tooling for different lengths, then length flexibility is achieved, but tooling costs for different inner diameters remain

Engineering Contradiction:
Improvelength adjustmentVSAvoidtooling cost for different diameters
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The frame is segmented into standardized modules with fixed inner diameters. By varying the number of modules assembled together, different overall diameters and lengths can be achieved using the same basic extrusion tooling. This modular approach eliminates the need for dedicated tooling for each diameter size.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A single extrusion tooling setup produces universal frame segments that can be configured into multiple frame sizes and lengths by simply changing the number of segments assembled. The same basic profile serves multiple diameter requirements through modular repetition.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Productivity

If modular frame construction is used, then production efficiency for various IEC standards is improved, but assembly complexity increases

Engineering Contradiction:
Improveproduction efficiencyVSAvoidassembly structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The frame is divided into standardized modular segments designed for efficient assembly. Each segment contains identical connection interfaces and cooling channel configurations, enabling rapid assembly through repetitive joining operations rather than complex custom fabrication for each IEC standard.

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

This method reduces tooling costs and enables the production of frames of desired lengths and diameters efficiently, accommodating various IEC standards, while maintaining effective cooling capabilities for electric machines.

Implementation Method 1

producing frame modules having an arc-shaped inner surface, the frame modules extending in the axial direction over a length of the frame and in the circumferential direction over a portion of the circumference of the frame

Methodology Applied
Scientific EffectGeometric curvature: Geometry

Implementation Method 2

welding adjacent frame modules to each other from the edges of the frame modules by welding the opposite side edges, in the circumferential direction, of adjacent frame modules together along the axial length of the side edges of the frame modules

Methodology Applied
Scientific EffectWelding: Welding

Implementation Method 3

machining an inner surface of the frame in order to achieve a circular inner opening of a desired diameter in the frame

Methodology Applied
Scientific EffectMachining: Abrasion

Implementation Method 4

each frame module comprising at least one axial cooling duct passing in the axial direction through the frame module, The electric machine may be cooled with liquid e.g. water passing in cooling ducts in the frame

Methodology Applied
Scientific EffectFluid flow through cooling ducts: Convection

Data Source

PatentEP3754818B1A frame of an electric machine
Publication Date: 2022.08.24 ABB (SCHWEIZ) AG
  • EP3754818B1 patent drawingFigure 1
  • EP3754818B1 patent drawingFigure 2
  • EP3754818B1 patent drawingFigure 3

AI summary

The frame comprises frame modules (50) with an arc-shaped inner surface (51). The frame modules extend in the axial direction over a length of the frame and in the circumferential direction over a portion of the circumference of the frame. Adjacent frame modules are attached to each other from the edges (53, 54) of the frame modules in order to form a continuous circular frame having a circular inner opening. Each frame module comprises at least one axial cooling duct (55).