Slotless Stator Winding Layout for Equal Coil Space Factor

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Solution Overview

Problem

The existing slotless rotary electric machine winding assemblies have inefficiencies in coil space utilization and precision due to unequal turns in inner and outer layers, leading to suboptimal torque and manufacturing challenges.

Innovation Solution

The winding assembly is designed with a two-layer structure where the number of turns in the outer layer exceeds that in the inner layer, ensuring equal coil space factors and efficient utilization of stator core space, while simplifying the manufacturing process through overlapping geometric projections and concentric circular arrangements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If each winding unit simultaneously occupies both inner layer and outer layer, then the winding assembly can be constructed, but the coil space factor of the outer layer becomes less than that of the inner layer, resulting in inefficient space utilization

Engineering Contradiction:
Improvecoil space factorVSAvoidwinding assembly construction
Core Design Contradiction:
Quantity of substanceVSEase of manufacture

Solution Approach 1:

The winding units are divided into two separate groups: a first winding group disposed at the inner layer and a second winding group disposed at the outer layer. This segmentation allows each layer to be optimized independently, with the outer layer winding units having greater numbers of turns to achieve equal coil space factors between layers, thereby resolving the space utilization inefficiency while maintaining manufacturing feasibility.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If the winding units are arranged with first lateral segments and second lateral segments on opposite sides, then a tubular structure is formed, but gaps and deviations occur, making it hard to improve the accuracy or precision of the winding assembly

Engineering Contradiction:
Improvewinding assembly accuracyVSAvoidwinding unit arrangement
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by making the profiles of the first lateral segment and second lateral segment symmetric with respect to a central line, and by specifically designing the outer layer winding units to have greater numbers of turns. This localized optimization of geometric properties ensures tight arrangement and equal coil space factors, thereby improving manufacturing precision without significantly increasing overall device complexity.

Inventive Principle:
Principle #3Local quality

3Quantity of substance

If the number of turns in outer layer winding units is increased to equalize coil space factors, then space utilization is improved, but the winding assembly becomes more complex to manufacture

Engineering Contradiction:
Improvespace utilizationVSAvoidwinding assembly structure
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent deliberately introduces asymmetry by setting different numbers of turns for inner layer and outer layer winding units. Specifically, the outer layer winding units have greater numbers of turns than the inner layer winding units. This asymmetric design compensates for the larger radial distance of outer layer units, achieving equal coil space factors and optimal space utilization while maintaining a relatively simple overall structure through the symmetric profile design of individual winding units.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3985842B1Stator and winding assembly thereof
Publication Date: 2024.02.14 DELTA ELECTRONICS INC(CN)
  • EP3985842B1 patent drawingFigure 1A
  • EP3985842B1 patent drawingFigure 1B
  • EP3985842B1 patent drawingFigure 2A

AI summary

The present disclosure provides a stator (2) and winding assembly (22) thereof. The stator (2) includes a stator core (21) including a tube wall (210) and a hollow portion (211) and a winding assembly (22). The winding assembly (22) is disposed in the hollow portion (211) and includes a first winding group (22a) and a second winding group (22b). The first winding group (22a) includes plural winding units (221, 222, 223) disposed on an inner side of the tube wall (210) and defining an outer layer. The second winding group (22b) includes plural winding units (224, 225, 226) disposed on an inner side of the outer layer and defining an inner layer. Any one of the projections of the winding units (224, 225, 226) at the inner layer is partially overlapped with the projections of the two adjacent winding units (221, 222, 223) at the outer layer. A number of turns of the winding units (221, 222, 223) of the first winding group (22a) is equal to or greater than that of the winding units (224, 225, 226) of the second winding group (22b).