Dual-Drum Washing Machine for Three-Dimensional Laundry Motion

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Solution Overview

Problem

Conventional washing machines limit laundry motion to two-dimensional circulation within the drum, leading to inefficient washing, increased washing time, and potential for clothes to become entangled and wrinkled during dehydration.

Innovation Solution

A washing machine design featuring two drums and a dual rotor motor system that allows for independent rotation of the drums, enabling three-dimensional motion of laundry through differential rotation speeds, along with optimized torque distribution and reduced magnetic flux leakage, to enhance washing efficiency and prevent entanglement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single drum is used for washing, then the device complexity is low, but the laundry motion is limited to two-dimensional circulation resulting in poor washing efficiency

Engineering Contradiction:
Improvewashing efficiencyVSAvoiddrum structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention employs a nested dual-drum structure where the inner drum is positioned inside the outer drum, both sharing a common axis. The inner drum rotates independently from the outer drum, enabling three-dimensional laundry motion without requiring separate washing chambers. This nesting approach achieves enhanced washing efficiency while maintaining a compact and relatively simple overall device structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention implements dynamic operation by enabling the inner drum and outer drum to rotate at different speeds and directions. During washing, the drums can rotate in opposite directions to create tumbling motion; during dehydration, they can rotate in the same direction at different speeds to prevent laundry entanglement. This dynamic control transforms the static single-drum system into an adaptable multi-motion system that significantly improves washing efficiency.

Inventive Principle:
Principle #15Dynamics

2Productivity

If high rotation speed is used for dehydration, then the dehydration efficiency is improved, but the laundry becomes entangled and stuck on the drum surface

Engineering Contradiction:
Improvedehydration efficiencyVSAvoidlaundry entanglement and wrinkles
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The invention applies dynamic speed differential control between the inner drum and outer drum during dehydration. Both drums rotate in the same direction but at different speeds, creating relative motion that prevents laundry from becoming stuck on the drum surface. The speed difference generates centrifugal force variations that continuously move the laundry, maintaining high dehydration efficiency while preventing entanglement and wrinkles.

Inventive Principle:
Principle #15Dynamics

3Productivity

If dual drum structure with independent rotation is implemented, then three-dimensional laundry motion is achieved improving washing efficiency, but the motor structure complexity increases

Engineering Contradiction:
Improvewashing efficiencyVSAvoidmotor structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention merges two motor functions into a single dual-rotor motor structure. The motor contains an inner rotor connected to the inner drum and an outer rotor connected to the outer drum, both sharing a common stator. This integrated motor design enables independent rotation control of both drums while avoiding the complexity of using two separate motors, thereby achieving three-dimensional laundry motion with improved washing efficiency without excessive motor structure complexity.

Inventive Principle:
Principle #5Merging (Combining)

4Adaptability or versatility

If conventional single rotor motor is used, then the motor structure is simple, but it cannot provide differential rotation for dual drums

Engineering Contradiction:
Improvedrum rotation control flexibilityVSAvoidmotor structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention segments the motor's rotational output by dividing it into two independent rotational systems within a single motor structure. The dual-rotor motor contains an inner rotor and an outer rotor that can rotate independently, each connected to respective drums. This segmentation of the motor structure provides the adaptability and versatility needed for differential drum rotation while maintaining a unified motor assembly rather than requiring two separate motors.

Inventive Principle:
Principle #1Segmentation

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 three-dimensional motion improves washing performance, reduces washing time, minimizes entanglement, and prevents wrinkles by ensuring smooth laundry movement and efficient torque distribution, while maintaining a compact motor size and reducing material waste.

Implementation Method 1

the washing machine is configured to run the rotation shaft by a driving motor, which has a rotor structure by use of permanent magnets

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The rotor is in a circular shape, and has a plurality of permanent magnets regularly aligned in an annular form

Methodology Applied
Scientific EffectMagnetic field interaction: Magnetic Field

Implementation Method 3

the rotor teeth form magnetic fluxes with the stator so as for the rotor to have a rotational force

Methodology Applied
Scientific EffectMagnetism: Magnetism

Implementation Method 4

The laundry is rotated along the inner circumferential surface of the drum by a centrifugal force responsive to the rotation of the drum

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 5

the laundry also performs a circular motion along the inner circumferential surface according to rotation speed of the drum and a falling motion from an upper side of the drum by the force of gravity

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 6

a washing machine forcibly spins the laundry within a drum by using a mechanical force, such as a frictional force generated between the drum, which is rotated by a driving force transferred from a driving motor, and the laundry

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2771506B1Washing machine
Publication Date: 2023.03.01 LG ELECTRONICS INC
  • EP2771506B1 patent drawingFigure 1~2
  • EP2771506B1 patent drawingFigure 3~4
  • EP2771506B1 patent drawingFigure 5~6

AI summary

Disclosed is a washing machine comprising a main drum rotatably mounted in the tub, a sub drum mounted inside the main drum to be relatively rotatable with respect to the main drum, an outer shaft for rotating the main drum, an inner shaft for rotating the sub drum and disposed inside the outer shaft, and a driving motor. The driving means is configured to rotate the main drum and the sub drum in different directions and/or with different rotational speeds. The washing machine further comprises a main drum spider to connect the main drum to the outer shaft to transfer a driving force of the driving means to the main drum, and a sub drum spider to connect the sub drum to the inner shaft to transfer a driving force of the driving means to the sub drum, wherein the two spiders are arranged to be independently rotatable.