C-Shaped Stator Element Alignment via Non-Magnetic Bridge

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Solution Overview

Problem

The alignment and assembly of stator elements in electrical machines with c-shaped cores are complicated by tolerance issues, leading to larger air gaps and reduced precision, which affects the machine's performance and reliability.

Innovation Solution

Moulding non-magnetic bridges onto the poles of c-shaped stator elements to secure and align them precisely, creating a unitary stator with a small air gap and well-defined saliencies, simplifying assembly and enhancing rotor alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If c-shaped cores are used to achieve high fill-factor and easier winding, then manufacturing ease is improved, but alignment precision deteriorates due to tolerance issues

Engineering Contradiction:
Improvewinding easeVSAvoidalignment precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

A non-magnetic bridge component is introduced as an intermediary element to connect and align the C-shaped stator cores. The bridge includes alignment features such as protrusions fitting into recesses or keyed interfaces that precisely position the stator cores relative to each other, eliminating alignment errors caused by tolerances in the C-shaped cores themselves.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The alignment features are pre-formed on the stator cores and bridge component during manufacturing. The precise geometric relationships are established in advance through precision machining or molding of the alignment features, so that when assembly occurs, the alignment is automatically achieved without requiring complex adjustment procedures.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If larger air gap is provided to accommodate tolerance in alignment, then reliability is improved by allowing free rotation, but magnetic performance deteriorates due to increased reluctance

Engineering Contradiction:
Improverotation freedomVSAvoidmagnetic performance
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The non-magnetic bridge serves as a mediator that provides precise alignment between stator cores, enabling the air gap to be minimized for optimal magnetic performance while still accommodating tolerance variations through the precision alignment features built into the bridge structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If stator elements are assembled as separate components, then ease of manufacture is improved, but assembly complexity increases due to simultaneous alignment requirements

Engineering Contradiction:
Improvecomponent fabricationVSAvoidassembly complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The bridge component acts as an intermediary that pre-establishes the spatial relationships between stator elements. This allows stator elements to be manufactured separately and then quickly assembled together through simple insertion or attachment to the bridge, eliminating the need for complex simultaneous alignment procedures.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The alignment features are pre-formed on the stator cores and bridge component during manufacturing. The precise geometric relationships are established in advance through precision machining or molding of the alignment features, so that when assembly occurs, the alignment is automatically achieved without requiring complex adjustment procedures.

Inventive Principle:
Principle #10Preliminary action

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 approach allows for precise alignment and assembly of stator elements, reducing air gap reluctance, improving rotor start-up conditions, and enabling accurate sensor positioning, thereby enhancing the electrical machine's performance and simplifying the assembly process.

Implementation Method 1

The air gap between the rotor and the stator is ideally as small as possible so as to reduce reluctance

Methodology Applied
Scientific EffectMagnetic reluctance: Magnetic Reluctance

Data Source

PatentEP2828952B1Stator for an electrical machine
Publication Date: 2020.04.29 DYSON TECH LTD
  • EP2828952B1 patent drawingFigure 1
  • EP2828952B1 patent drawingFigure 2

AI summary

A stator comprising a plurality of stator elements, each stator element comprising a c-shaped core having two poles. Each pole of each stator element is secured to a pole of an adjacent stator element by a bridge formed of a non-magnetic material moulded onto the poles.