Asymmetrical Pole Tip Lamination Stack for Electric Motors

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Solution Overview

Problem

Manufacturers of washing machines and electric motors face pressures to reduce costs, improve performance, and enhance energy efficiency, with existing technologies not adequately addressing these needs through modular designs and efficient material usage.

Innovation Solution

A lamination stack for electrical machines is developed using multiple sheet metal profiles with asymmetrical pole tip profiles, forming a helically-wound spiral stack that provides symmetry and efficiency, including a method of manufacturing these stacks by intermeshing and inverting sheet metal profiles to create a combined profile with pole stems and extensions on both sides, allowing for improved magnetic field coupling and reduced material waste.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional symmetrical pole profiles are used, then manufacturing is simpler, but material usage is inefficient and performance is suboptimal

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidmaterial usage efficiency
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The patent applies asymmetry by using asymmetrical pole profiles in the sheet metal laminations. Each pole has an asymmetrical profile with a pole stem and a pole extension on one side only, creating a T-shaped cross-section. This asymmetrical design allows for more efficient material distribution and magnetic flux paths while maintaining manufacturability through standard stamping processes.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent transitions from traditional 2D symmetrical pole faces to a 3D asymmetrical pole structure with extensions. The pole extension protrudes from the pole stem in a specific direction, creating a three-dimensional profile that optimizes magnetic coupling and flux distribution throughout the stator assembly.

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

2Quantity of substance

If complex asymmetrical profiles are used, then material usage efficiency improves, but manufacturing complexity increases

Engineering Contradiction:
Improvematerial usage efficiencyVSAvoidprofile complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The asymmetrical pole profile is segmented into distinct functional portions: a pole stem portion that provides structural support and magnetic flux path, and a pole extension portion that optimizes magnetic coupling with adjacent poles. This segmentation allows each portion to be optimized independently while maintaining overall manufacturability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The asymmetrical pole profile serves multiple functions simultaneously: the pole stem provides structural integrity and magnetic flux path, while the pole extension enhances magnetic coupling and flux distribution. This multi-functionality is achieved within a single stamping operation, avoiding the need for separate manufacturing steps.

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

3Adaptability or versatility

If modular assemblies are implemented, then cost reduction and versatility improve, but design complexity increases

Engineering Contradiction:
Improvedesign versatilityVSAvoiddesign complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The asymmetrical pole profile with pole stem and extension is designed as a universal component that can be applied across different motor sizes and applications. The same basic profile structure serves multiple functions and can be scaled for various power requirements, enabling modular design approaches.

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

Solution Approach 2:

The modular asymmetrical pole design allows for parameter variations (such as extension length, stem thickness, and lamination count) to be adjusted for different applications while maintaining the same fundamental structure. This enables cost-effective modular assemblies that can be adapted to various motor specifications.

Inventive Principle:
Principle #35Parameter changes

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 solution enhances the efficiency and cost-effectiveness of electric motors by improving magnetic field coupling, reducing material usage, and allowing for modular designs that can be applied to various applications, such as washing machines and hybrid vehicles, while maintaining performance and energy efficiency.

Implementation Method 1

the asymmetrical pole tip profiles of the multiple sheet metal profiles producing a combined profile having a pole stem and a pole extension either side of the pole stem so that the stack has symmetry when viewed in the axial direction

Methodology Applied
Scientific EffectMagnetic field coupling: Magnetic Field

Data Source

PatentEP2789074B1Electrical machine
Publication Date: 2020.04.01 FISHER & PAYKEL APPLIANCES LTD
  • EP2789074B1 patent drawingFigure 1
  • EP2789074B1 patent drawingFigure 2
  • EP2789074B1 patent drawingFigure 3

AI summary

A method of making lamination stacks for electrical machines comprises producing generally symmetrical pole tips from alternating asymmetrical pieces. With the alternating asymmetrical pieces combined, the resulting pole tip is generally symmetrical with a larger possible pole tip width compared with currently-used stamping techniques.