Laundry Drum Suspension Fault Detection Using Gravity Sensing

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Solution Overview

Problem

Existing household appliances for laundry care, such as washing machines and tumble dryers, face issues with detecting faulty oscillating devices due to broken or worn springs and dampers, leading to imbalance and potential damage to other components.

Innovation Solution

Incorporating an acceleration sensor with multiple measuring axes attached to the drum or tub to measure the direction of gravitational acceleration, allowing for precise detection of even slight deviations from a standard state, thereby identifying error states quickly and accurately without additional components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If an oscillating device is used to mount the drum in the housing, then the drum can carry out oscillating movements relative to the housing during operation, but the oscillating device may develop fault conditions due to broken or worn springs and dampers leading to imbalance and mechanical stress on other components

Engineering Contradiction:
Improveoscillating movement capabilityVSAvoidfault detection capability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary detection by measuring the gravitational acceleration vector in the idle state before operation begins. This allows fault detection to occur before the oscillating device is activated, enabling preventive maintenance and avoiding damage to other components that would result from operating with a faulty oscillating device.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the acceleration sensor is positioned on the oscillating components (springs/dampers), then direct measurement of their state is possible, but the sensor experiences undesirably high loads and mechanical stress during operation

Engineering Contradiction:
Improvedirect component state measurementVSAvoidsensor load承受能力
Core Design Contradiction:
Measurement precisionVSStrength

Solution Approach 1:

The drum serves as an intermediary carrier for the acceleration sensor. Instead of mounting the sensor directly on the oscillating springs or dampers, it is mounted on the drum which experiences lower mechanical loads. The drum's position and orientation during idle state still accurately reflect the state of the oscillating device, allowing indirect but reliable fault detection without subjecting the sensor to excessive mechanical stress.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If multiple sensors are added to detect different fault conditions, then detection accuracy improves, but device complexity and space requirements increase

Engineering Contradiction:
Improvefault detection accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

A single acceleration sensor performs multiple functions: it detects broken springs, worn dampers, and asymmetric mounting conditions by measuring the gravitational acceleration vector in different orientations. The sensor's ability to detect faults in multiple oscillating components simultaneously demonstrates multi-functionality, achieving comprehensive fault detection without requiring separate sensors for each component.

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

Solution Approach 2:

The mechanical system of multiple sensors is replaced by a single electronic acceleration sensor that uses gravitational field measurement to detect mechanical faults. This substitution of mechanical detection methods with electronic sensing achieves equivalent or superior detection capability while reducing system complexity and component count.

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

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 enables early and precise identification of oscillating device faults, minimizing mechanical stress on other components and preventing malfunctions or damage, while maintaining a simplified design and avoiding sensor overload during operation.

Implementation Method 1

the direction of the gravitational acceleration relative to the acceleration sensor can be measured

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP2794974B1Household appliance for caring for pieces of laundry as well as a method for determining an error status of an oscillating device in a household appliance
Publication Date: 2015.09.16 BSH HAUSGERATE GMBH
  • EP2794974B1 patent drawingFigure 1~2

AI summary

The invention relates to a household appliance (1) for caring for pieces of laundry which has a drum (3) for accommodating the pieces of laundry and a housing (2) in which the drum (3) is mounted with an oscillating device (5), wherein the oscillating device (5) has an apparatus (10) for recognising an error status of the oscillating device (5), wherein the apparatus (10) comprises at least one acceleration sensor (11) that can be used to measure the direction (12) of the gravitational acceleration relative to the acceleration sensor (11), and depending on the result, an error status of the oscillating device (5) can be recognised. The invention also relates to a method for determining an error status of an oscillating device (5) in a household appliance (1).