Segmented Stator Teeth with Over-Moulded Insulation

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Solution Overview

Problem

Traditional stator designs with solid back-iron and integral teeth face limitations in coil winding efficiency due to space constraints and poor thermal conductivity, requiring complex winding processes and risking distortion during injection moulding of insulation layers.

Innovation Solution

The design features radially mounted stator teeth with resilient elements and an over-moulded plastics layer, allowing for easier coil winding and improved thermal conductivity, while minimizing distortion risks and enabling separate tooth mounting to a circumferential support, using different materials for insulation and injection moulded layers based on specific properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the entire stator is formed of a single solid piece, then structural strength is improved, but space for coil windings is limited and manufacturing complexity increases

Engineering Contradiction:
Improvestructural strengthVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The stator is divided into separate components: a stator back-ring and multiple radially mounted stator teeth. This segmentation allows each tooth to be independently manufactured and assembled, reducing overall manufacturing complexity while maintaining structural integrity through proper joining mechanisms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Coil windings are formed around the stator teeth before the teeth are mounted to the stator back-ring. This preliminary action allows for optimized coil placement and reduces the complexity of the final assembly process, as coils are pre-positioned rather than requiring complex in-situ winding operations.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If an injection moulded plastics layer is applied to the tooth, then electrical insulation and thermal conductivity are improved, but the tooth may be distorted by high pressures

Engineering Contradiction:
Improveelectrical insulationVSAvoidtooth distortion
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The injection moulded plastics layer is applied to the stator tooth before the tooth is mounted to the stator back-ring. This preliminary application allows the insulation layer to be formed under controlled conditions, and the subsequent mounting process is designed to accommodate the insulated tooth without causing distortion.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The injection moulding process parameters are optimized for the specific local conditions of the stator tooth geometry. The moulding pressure, temperature, and injection rate are controlled to provide adequate electrical insulation while minimizing the risk of distorting the tooth structure during the insulation application process.

Inventive Principle:
Principle #3Local quality

3Reliability

If coil windings are wound around integral teeth, then electrical connection is improved, but space utilization is poor and thermal conductivity decreases

Engineering Contradiction:
Improveelectrical connectionVSAvoidspace utilization
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The stator teeth are separated from the stator back-ring and can be radially mounted after coil windings are formed. This segmentation creates gaps between adjacent teeth that can be filled with additional coil windings, improving space utilization and allowing for larger total cross-section of coil windings to reduce resistance and improve thermal conductivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The stator teeth are arranged in a radial configuration around the stator back-ring, utilizing the radial dimension to optimize coil winding placement. This radial arrangement allows coil windings to be positioned in the gaps between teeth while maintaining electrical connection, effectively using three-dimensional space more efficiently.

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

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 reduces manufacturing complexity and cost, enhances thermal conductivity, and improves electrical insulation, facilitating efficient coil winding and assembly while maintaining mechanical strength and guiding coil windings effectively.

Implementation Method 1

The use of an over moulded layer applied to single stator tooth can minimise the risk of any air gaps forming between the insulation layer and the stator tooth, thereby providing an electrical insulation layer between the coils and the stator

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 2

The use of an over moulded layer applied to single stator tooth can minimise the risk of any air gaps forming between the insulation layer and the stator tooth, thereby providing an electrical insulation layer between the coils and the stator while also improving thermal conductivity

Methodology Applied
Scientific EffectThermal conductivity: Conduction (thermal)

Implementation Method 3

The design features radially mounted stator teeth with resilient elements

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2907223B1Teeth of an electric motor or generator
Publication Date: 2023.07.12 PROTEAN ELECTRIC LIMITED
  • EP2907223B1 patent drawingFigure 1
  • EP2907223B1 patent drawingFigure 2~2b
  • EP2907223B1 patent drawingFigure 3

AI summary

A stator or rotor for an electric motor or generator comprising a plurality of teeth for receiving coil windings, wherein each tooth has an injection moulded plastic layer formed on a plurality of sides of each tooth with a first gap formed in the injection moulded plastic layer on a first side of each of the teeth with a first insulation element placed in the first gap formed in the injection moulded plastic layer, wherein the injection moulded plastic layer and first insulation element are arranged to electrically insulate the plurality of teeth from the coil windings.