Washing Machine Motor Stator Auxiliary Core Magnetic Resistance

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Solution Overview

Problem

Conventional direct connection type drum washing machines experience increased magnetic resistance, cogging torque, and noise due to the space between stator teeth, which reduces effective torque and increases material costs.

Innovation Solution

A motor design featuring a stator with a main core having protruded teeth and an auxiliary core that shields the spaces between teeth, reducing magnetic resistance and cogging torque, while maintaining a straight tooth shape to minimize scrap and costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If space is formed between adjacent stator teeth to facilitate coil winding, then ease of manufacture is improved, but magnetic resistance increases and effective torque decreases

Engineering Contradiction:
Improveease of coil windingVSAvoidmagnetic resistance
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

An auxiliary core is introduced as an intermediary component between the main core teeth. This auxiliary core fills the spaces between adjacent teeth, serving as a mediator that maintains magnetic flux continuity while allowing sufficient space for coil winding operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The stator core is constructed as a composite structure combining a main core with protruded teeth and an auxiliary core with recessed portions. This composite design allows the auxiliary core material to fill gaps and provide magnetic path continuity while the main core provides the structural framework for coil winding.

Inventive Principle:
Principle #40Composite materials

2Loss of energy

If trapezoidal tip shape is given to stator teeth to reduce magnetic resistance, then magnetic performance is improved, but manufacturing cost increases due to increased scrap

Engineering Contradiction:
Improvemagnetic resistanceVSAvoidmanufacturing cost
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

The stator core is segmented into two functional parts: the main core with simple straight teeth for easy manufacturing, and the auxiliary core with specifically shaped recessed portions that reduce magnetic resistance. This segmentation allows each part to be optimized independently for its specific function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The auxiliary core provides localized magnetic resistance reduction at the tooth tips and spaces where it is most needed, while the main core maintains simple straight teeth throughout for easy manufacturing. This local quality approach applies complex geometry only where necessary rather than throughout the entire structure.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If space exists between stator teeth, then coil winding is facilitated, but cogging torque and torque ripple increase

Engineering Contradiction:
Improvecoil windingVSAvoidcogging torque
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The auxiliary core acts as an intermediary that modifies the magnetic field distribution in the spaces between teeth. By providing magnetic path continuity through these spaces, it mediates between the need for winding space and the need to minimize cogging torque.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The auxiliary core's recessed portions are designed to dynamically adapt to the relative position variations between rotor and stator during operation, maintaining optimal magnetic flux distribution that reduces cogging torque while preserving winding accessibility.

Inventive Principle:
Principle #15Dynamics

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

The design effectively reduces cogging torque and torque ripple, enhances motor performance, and decreases noise and material costs by optimizing the magnetic flux path and reducing scrap production during manufacturing.

Implementation Method 1

an auxiliary core for shielding a space defined between adjacent teeth of the main core, thereby reducing a magnetic resistance generated due to the space

Methodology Applied
Scientific EffectMagnetic resistance: Magnetic Reluctance

Implementation Method 2

a device for generating dynamic energy using an electromagnetic force generated when current flows through a conducting wire arranged in an area where a magnetic field is generated

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP1793468B1Motor, method for manufacturing the same, and washing machine using the same
Publication Date: 2018.07.11 LG ELECTRONICS INC
  • EP1793468B1 patent drawingFigure 1
  • EP1793468B1 patent drawingFigure 2
  • EP1793468B1 patent drawingFigure 3

AI summary

A motor having a structure configured to reduce magnetic resistance between a rotor and a stator, a method for manufacturing the motor, and a washing machine using the motor are disclosed. The motor includes a rotor, and a stator co-operating with the rotor. The stator includes a main core and an auxiliary core. The main core includes a base and a plurality of teeth protruding from the base. The auxiliary core is structured to prevent the occurrence of magnetic resistance from being generated from spaces, defined between adjacent teeth, when the stator co-operates with the rotor.