Washing Machine Spin Control for Faster Laundry Rebalancing

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Solution Overview

Problem

Washing machines face challenges in achieving balanced laundry distribution during the spin phase, leading to vibrations and reduced efficiency due to uneven distribution of laundry items, which affects the drum's ability to reach target speeds and increases energy consumption.

Innovation Solution

A method for controlling the spin phase in a washing machine that involves adjusting the drum speed to redistribute laundry items before each spin step, with specified maximum distribution time and attempts to minimize imbalance, using a difference calculation to determine the further course of the spin phase and incorporating time credits for optimal distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the drum speed is increased to achieve high spin speeds for low residual moisture, then the spin efficiency is improved, but the vibrations and imbalance increase due to uneven laundry distribution

Engineering Contradiction:
Improvespin efficiencyVSAvoidvibrations
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by performing laundry redistribution before the spin phase through controlled acceleration and deceleration of the drum. The control unit executes redistribution phases that increase drum speed to detach laundry from the inner wall, then decrease speed to allow redistribution, ensuring balanced distribution before high-speed spinning begins. This prevents vibrations during the actual spin cycle.

Inventive Principle:
Principle #10Preliminary action

2Stability of the object's composition

If the drum speed is adjusted to redistribute laundry items, then the imbalance is reduced, but the spin phase duration increases due to additional distribution steps

Engineering Contradiction:
Improvelaundry distribution balanceVSAvoidspin phase duration
Core Design Contradiction:
Stability of the object's compositionVSDuration of action of moving object

Solution Approach 1:

The patent applies dynamics by making the drum speed variable during the spin phase. The control unit dynamically adjusts the drum speed between different phases: increasing speed during redistribution phases to detach laundry, decreasing speed to allow redistribution, and then increasing to target spin speed. This dynamic speed control enables both redistribution and efficient spinning within an optimized total duration.

Inventive Principle:
Principle #15Dynamics

3Stability of the object's composition

If multiple redistribution phases are implemented to achieve balanced distribution, then the imbalance is minimized, but the energy consumption increases due to repeated acceleration and deceleration

Engineering Contradiction:
Improvelaundry distribution balanceVSAvoidenergy consumption
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The patent applies feedback by using sensors to detect the distribution state of laundry in the drum and adjusting the drum speed accordingly. The control unit receives feedback about laundry position and mass distribution, then determines the optimal number and duration of redistribution phases needed to achieve balanced distribution, avoiding unnecessary acceleration and deceleration cycles.

Inventive Principle:
Principle #23Feedback

4Stability of the object's composition

If the drum is accelerated slowly during a predetermined time period to distribute laundry, then the distribution is improved, but the time required before reaching spin speed increases

Engineering Contradiction:
Improvelaundry distributionVSAvoidtime to reach spin speed
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent applies periodic action by implementing alternating phases of acceleration and deceleration during the spin cycle. Instead of continuous slow acceleration, the control unit executes periodic cycles: accelerate to detach laundry, decelerate to allow redistribution, then accelerate again. This periodic pattern achieves better distribution more quickly than continuous slow acceleration, reducing the total time to reach optimal spin speed.

Inventive Principle:
Principle #19Periodic action

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 approach allows for an optimal spin phase with balanced distribution, reducing residual moisture, energy consumption, and spin noise, while enabling high drum speeds and efficient detergent residue removal, thus improving the overall laundry treatment process.

Implementation Method 1

When spinning, the drum of the washing machine rotates at a very high speed, for example 1,200 rpm. The items of laundry lie firmly against an inner wall of the drum.

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

The laundry system speed depends on the load of laundry items in the drum. A specific proportion of the laundry items can thus be detached from the inner wall of the drum in a targeted manner by a suitable selection of a rotational speed.

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 3

If these items of laundry are unevenly distributed on the inner wall of the drum, there is an imbalance. The drum begins to vibrate, which also affects the parts connected to the drum, such as the tub and motor.

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP2785904B1Method for operating a washing machine having an improved spin cycle
Publication Date: 2016.02.10 BSH HAUSGERATE GMBH

AI summary

The invention relates to a method for controlling a spin cycle having a plurality of spin steps in a laundry treatment method in a washing machine having a drum, mounted rotatably around a substantially horizontal axis in a detergent vessel, wherein the pieces of laundry are distributed in an inner chamber of the drum by an increasing and/or lowering of a speed of the drum in the spin cycle before every spin step in a laundry distributing step, wherein a maximum distributing time (tmax n) and/or a maximum number (mtr n) of distributing attempts for reaching or falling short of a maximum value (Dmax 1) of an acceptably irregular distribution of the laundry pieces is specified for the laundry distributing step (n) before the spin step (n), wherein (a) the actually required time tact n is determined for every laundry distributing step (n); (b) a difference Δtn = tset n-tact n between the actual time (tact n) and a specified time (tset n) for the laundry distributing step (n) is calculated; and (c) a decision on the further course of the spin cycle is made depending on the calculated difference Δtn = tset n-tact n. The invention additionally relates to a washing machine suitable for carrying out said method.