Water Pocket Drum Balancing for Washing Machine Spin Vibration

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Solution Overview

Problem

Washing machines experience vibrations during centrifugation due to uneven laundry distribution in the drum, leading to unbalanced rotating inertia forces, which current solutions either require significant structural modifications or result in reduced drum size and increased mass, limiting laundry capacity.

Innovation Solution

A system comprising a vibration measuring system with sensors, an electronic control circuit, and a variable-intensity counteracting force generation system using pockets at the drum's circumference, filled and emptied by controlled valves to offset the imbalance, allowing for precise regulation of counteracting forces to match the laundry's dewatering progress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If additional masses are added to balance vibrations, then vibration reduction is achieved, but the washing machine becomes heavier

Engineering Contradiction:
ImprovevibrationVSAvoidwashing machine mass
Core Design Contradiction:
Object-affected harmful factorsVSWeight of stationary object

Solution Approach 1:

The patent uses movable counterweights that can dynamically adjust their position and mass distribution during the centrifugation cycle. The counterweights are not fixed but can move along the drum circumference, allowing the system to adapt to changing laundry distribution patterns and maintain balance without adding excessive permanent mass to the washing machine structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the mass parameter of the counterbalancing system by using pockets that can be filled with or emptied of water. This allows the counterweight mass to be variable rather than fixed, enabling precise adjustment to match the actual imbalance caused by laundry distribution while avoiding the need for a constantly heavy counterbalancing structure.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If drum diameter is reduced to avoid tub-casing contact, then vibration control is improved, but laundry capacity is reduced

Engineering Contradiction:
ImprovevibrationVSAvoiddrum capacity
Core Design Contradiction:
Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The patent introduces a counterweight system consisting of water-filled pockets positioned opposite to the laundry mass distribution. These pockets generate counteracting centrifugal forces that balance the vibrations caused by uneven laundry distribution, allowing the drum to maintain its full diameter and capacity without excessive vibration or tub-casing contact.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

3Device complexity

If fixed counterweight systems are used, then structural simplicity is maintained, but adaptability to changing laundry distribution is reduced

Engineering Contradiction:
Improvecounterweight system structureVSAvoidresponse to laundry redistribution
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The system incorporates sensors that continuously monitor the vibration and mass distribution in the drum. This feedback information is used by the control system to adjust the water level in the counterweight pockets, enabling the system to adapt to changing laundry distribution patterns while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent uses hydraulic principles by filling and emptying water pockets to adjust counterweight mass. This allows for smooth, continuous adjustment of the counterbalancing force without complex mechanical moving parts, maintaining structural simplicity while achieving high adaptability to changing conditions.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 effectively minimizes or eliminates vibrations by balancing rotating inertia forces, reducing stress on bearings and maintaining the drum's geometry and capacity, while allowing for quiet nighttime operation without extensive architectural changes.

Implementation Method 1

a vibration measuring system, including a sensor

Methodology Applied
Scientific EffectVibration: Vibration

Implementation Method 2

a system of pockets open at the minimum radius, or watertight pockets, located at a circumference of the drum, which may be filled with water via first valves controlled by the control system, and then selectively emptied via second valves also controlled by the control system, so as to generate a rotary force of equal intensity to that produced by the laundry but in the opposite direction

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2643511B1System to balance rotating inertia forces during centrifugation in a washing machine
Publication Date: 2015.10.14 BSH HAUSGERATE GMBH
  • EP2643511B1 patent drawingFigure 1~2
  • EP2643511B1 patent drawingFigure 3~4
  • EP2643511B1 patent drawingFigure 5~6

AI summary

The invention presents a system to control vibrations induced by poor distribution of the laundry in a washing machine during the centrifugation phase, based on the measurement of timing and intensity of the said forces by means of an accelerometer, and of the consequent generation of two counteracting rotating forces by means of the masses of water contained in suitable pockets (1), open at the inner radius (3) and located on the outside of the drum (5), or watertight and located on the inner edge of the drum, which are filled before centrifugation, and partially drained in a controlled fashion once the actual imbalance has been determined. The system features electronically controlled valve systems which can regulate both the uniform filling phase (where included) and the controlled drainage phase.