Washer Drum Position Sensing Using 3D Hall Detection

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Solution Overview

Problem

Existing laundry treatment appliances, such as washing machines and tumble dryers, face challenges in accurately measuring the position and imbalance of a suspended container, particularly during spin cycles, as current detection methods can only record vertical movements and are prone to failure due to dirt accumulation or limited spatial coordination detection.

Innovation Solution

A laundry treatment appliance equipped with a detection device that generates a magnetic field and uses Hall elements to detect magnetic flux density and field line directions, allowing for three-axis spatial coordinate monitoring of the container's position, enabling reliable load and imbalance measurement and preventing container impacts by monitoring movements in multiple directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a Hall element is used to detect magnetic flux density for position measurement, then vertical position detection is enabled, but horizontal position detection is not possible

Engineering Contradiction:
Improvevertical position detectionVSAvoidspatial detection capability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent transitions from one-dimensional (vertical) position detection using a single Hall element to three-dimensional spatial detection by incorporating three orthogonal Hall elements (X, Y, Z axes). This dimensional expansion enables comprehensive monitoring of container position in all spatial directions, resolving the limitation of vertical-only detection.

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

Solution Approach 2:

The detection device is designed with multi-functional capability by integrating three Hall elements that can simultaneously detect position information along three different axes. This universal detection system replaces the need for separate detection mechanisms for vertical and horizontal movements, enabling comprehensive position monitoring with a unified device.

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

2Measurement precision

If an optical distance measuring device is used, then vertical position measurement is achieved, but the device is susceptible to failure due to dirt accumulation

Engineering Contradiction:
Improvevertical position measurementVSAvoiddevice operation reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the optical distance measuring device with a magnetic field-based detection system using Hall elements. This substitution eliminates the optical path that is vulnerable to dirt accumulation, as the magnetic field sensing mechanism is not affected by optical obstructions, thereby significantly improving reliability in dirty environments.

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

Solution Approach 2:

The detection method changes from optical parameter measurement (light intensity, distance) to magnetic field parameter measurement (magnetic flux density). This parameter transformation fundamentally alters the detection mechanism's sensitivity to environmental contaminants, making it robust against dirt accumulation while maintaining measurement precision.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If a magnetic field generating element and detector device are used to detect magnetic flux density, then position detection is enabled, but lateral displacement detection is not possible

Engineering Contradiction:
Improveposition detectionVSAvoidlateral position information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent enhances the detection capability from one-dimensional (distance-based) to three-dimensional spatial detection by arranging three Hall elements orthogonally. Each element detects magnetic flux density along a specific axis, and through coordinate transformation, complete lateral and vertical position information is recovered, eliminating information loss.

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

Solution Approach 2:

The system uses the magnetic flux density measurements from three orthogonal Hall elements as feedback signals to calculate the container's three-dimensional position. By continuously monitoring the magnetic field variations along all three axes, the system maintains complete positional awareness and prevents lateral displacement information loss.

Inventive Principle:
Principle #23Feedback

4Measurement precision

If three orthogonal Hall elements are used to detect magnetic flux density in three directions, then three-dimensional position detection is enabled, but device complexity increases

Engineering Contradiction:
Improvethree-dimensional position detectionVSAvoiddetection device structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines three separate position detection functions (along X, Y, Z axes) into a single integrated detection device. By merging the three Hall elements and their associated circuitry into one unified module, the system achieves three-dimensional detection capability while minimizing the increase in overall device complexity through functional integration.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The detection device is designed as a universal three-axis sensor that performs multiple detection functions simultaneously. This multi-functional design eliminates the need for separate detection mechanisms for each spatial dimension, thereby achieving comprehensive three-dimensional position detection without proportionally increasing device complexity.

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

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

This solution provides accurate and reliable load and imbalance measurement, allowing for early detection of critical states and initiation of control measures to prevent container impacts, ensuring safe operation and efficient processing.

Implementation Method 1

an element (2b) generating a magnetic field

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

a detector device (2a) for detecting a magnetic flux density of the magnetic field

Methodology Applied
Scientific EffectMagnetic flux density detection: Hall Effect

Data Source

PatentEP2162579B1Laundry treatment device
Publication Date: 2012.02.01 BSH HAUSGERATE GMBH
  • EP2162579B1 patent drawingFigure 1
  • EP2162579B1 patent drawingFigure 2

AI summary

The invention relates to a laundry treatment device, particularly a washing machine, or a laundry dryer, comprising a housing (1), a container (3) suspended in the housing (1) in a swiveling manner, and an apparatus (2) for detecting the position and/or the arrangement of the container (3) in the housing (1), wherein the detection unit (2) comprises a magnetic field-generating element (2b) and a detector unit (2a) for detecting a magnetic flux density of the magnetic field. The position detection unit (2) is characterized in that the detector unit (2a) also detects the direction of the magnetic field lines of the magnetic field and determines the position of the container (3) as a function of the flux density and the field line direction.