Stator Coil Locking Rings for Secure Preformed Coil Assembly

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Solution Overview

Problem

Existing solutions for securing preformed coil assemblies on stator teeth in electric motors are not reliable and efficient, particularly in applications where potting is not feasible, such as low-ambient-temperature motors, and there is a need for a cost-effective and easy assembly method.

Innovation Solution

A stator design featuring a cylindrical core with radially extending teeth, upper and lower coil locking layers, and preformed coil assemblies with elongated openings and T-shaped mating parts, where winding carriers with projecting mating parts are securely locked by complementary mating openings in the coil locking rings, preventing axial, radial, and tangential movements, and using a method that includes supporting rings and coil locking rings for assembly and impregnation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If winding carriers are used to centre and secure coils on stator teeth, then coil positioning and electrical insulation are improved, but the reliability of securing the winding carriers to the stator teeth is insufficient

Engineering Contradiction:
Improvecoil positioningVSAvoidsecuring reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The coil assembly is segmented into multiple components: the winding carrier, the coil, and the locking element. The locking element is further segmented with multiple protrusions that engage with corresponding recesses in the stator tooth, distributing the securing function across multiple contact points rather than a single attachment method.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking element is nested within the winding carrier structure, with the protrusions extending from the locking element fitting into recesses on the stator tooth. This nested arrangement allows the locking mechanism to be integrated into the overall coil assembly while maintaining secure engagement with the stator.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If potting is used to protect and fix stator components, then thermal dissipation and component fixation are improved, but the solution becomes inapplicable in low-ambient-temperature environments due to cracking

Engineering Contradiction:
Improvecomponent protectionVSAvoidtemperature range applicability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent extracts the fixation function from the potting process and implements it through a mechanical locking mechanism. The locking element with protrusions and recesses provides structural fixation without requiring synthetic resin, thereby eliminating the temperature-related cracking issue while maintaining component security.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The chemical bonding mechanism of potting (synthetic resin) is replaced with a purely mechanical locking system. The protrusions and recesses create a mechanical interlock that secures the coil assembly to the stator tooth, substituting the need for temperature-sensitive bonding materials with a temperature-independent mechanical solution.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If a mechanical locking mechanism with multiple components is implemented, then securing reliability is improved, but device complexity increases

Engineering Contradiction:
Improvecoil assembly fixationVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking element is merged with the winding carrier in terms of functional integration. While the locking element is a separate component, it is designed to work in conjunction with the winding carrier as a unified assembly, reducing the need for additional separate fastening mechanisms and simplifying the overall construction.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The locking element serves multiple functions simultaneously: it provides mechanical retention by engaging with the stator tooth, maintains proper coil positioning, and ensures electrical insulation. This multi-functionality reduces the need for separate components for each function, thereby limiting the increase in overall device complexity.

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

Data Source

PatentEP3840185B1Stator for electric motors comprising preformed coil assemblies mounted thereon
Publication Date: 2024.10.09 ETEL SA
  • EP3840185B1 patent drawingFigure 1~2
  • EP3840185B1 patent drawingFigure 3~4
  • EP3840185B1 patent drawingFigure 5a~5b

AI summary

The invention relates to stator (10) for electric motors, comprising a core (12) having an upper and a lower portion (12a, 12b) and comprising teeth (14) forming slots (16) therebetween, a first and a second coil locking layer (19a, 19b) fixedly mounted on respective upper and lower portions (12a, 12b) of said core (12), and a plurality of preformed coil assembly (30) mounted on respective tooth (14) of said core (12). Each coil would carrier (30) comprises a winding section (32) comprising an elongated opening (34) configured to be adjusted around the corresponding tooth (14), and a first and a second winding carrier (35a, 35b) connected to respective opposite ends of the winding section (32). The first and second winding carriers (35a, 35b) of each of said plurality of preformed coil assemblies (30) comprise each a projecting mating part (20) while said first and second coil locking rings (19a, 19b) comprise each a corresponding plurality of mating openings (40) of complementary shape inside which are fitted the projecting mating part (20) of respective first and second winding carriers (35a, 35b) of one of said plurality of preformed coil assemblies (30).