Electric Motor Stator Core Thinning via Insulator Segmentation

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Solution Overview

Problem

Conventional inner rotor type electronic motors face challenges in increasing rotor diameter while maintaining the outside diameter of the stator unchanged, leading to issues with stator core thinning and accurate coil winding positioning due to reduced stator core rigidity.

Innovation Solution

The stator core is thinned by creating cut-away parts at predetermined intervals on the insulator flanges, allowing for precise positioning during coil winding and enabling increased rotor diameter without altering the stator's outside diameter, with the insulator divided into segments for cost-effective manufacturing and assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the rotor diameter is increased to increase power output, then the power output is improved, but the stator outside diameter must be increased accordingly

Engineering Contradiction:
Improvepower outputVSAvoidstator outside diameter
Core Design Contradiction:
PowerVSLength of stationary object

Solution Approach 1:

The patent shifts the design constraint from the radial dimension (stator outside diameter) to the axial dimension (stator core thickness). By reducing the stator core thickness in the axial direction, the rotor diameter can be increased while maintaining the same stator outside diameter, thus resolving the contradiction between power output and stator size.

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

2Length of stationary object

If the stator core thickness is reduced to increase rotor diameter, then the rotor diameter is improved, but the positioning accuracy during coil winding deteriorates

Engineering Contradiction:
Improverotor diameterVSAvoidpositioning accuracy
Core Design Contradiction:
Length of stationary objectVSManufacturing precision

Solution Approach 1:

The insulator is divided into multiple segments that can be assembled around the stator core. These segmented insulators provide positioning protrusions that engage with corresponding positioning grooves on the stator core, enabling accurate positioning during coil winding even when the stator core is thin.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The insulator acts as an intermediary component between the stator core and the coil winding process. By providing positioning protrusions on the insulator, the system achieves accurate positioning without relying on the stator core's own geometric features, thus resolving the positioning accuracy issue.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Length of stationary object

If the stator core is thinned to increase rotor diameter, then the rotor diameter is improved, but the stator core rigidity deteriorates

Engineering Contradiction:
Improverotor diameterVSAvoidstator core rigidity
Core Design Contradiction:
Length of stationary objectVSStrength

Solution Approach 1:

The patent uses a composite structure combining the stator core with the insulator material. The insulator provides additional structural support and rigidity to the thinned stator core, compensating for the reduced stiffness while allowing the rotor diameter to be increased.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2209181B1Electric motor
Publication Date: 2018.09.12 FUJITSU GENERAL LTD
  • EP2209181B1 patent drawingFigure 1
  • EP2209181B1 patent drawingFigure 2
  • EP2209181B1 patent drawingFigure 3

AI summary

There is provided an electronic motor in which a stator core is thinned to obtain an increased diameter of a rotor is to produce a high power output, and a stator can be positioned with high accuracy at the time when a coil is wound on the stator. The outside peripheral surface of a yoke part 31 is substantially the same as the outside peripheral surface of a flange 42 of an insulator 4, and in a part of the flange 42, a cut-away part 43 is provided to expose a part of the end face of a stator core 30.