DE102010063134B4 - Method for operating a household appliance and household appliance - Google Patents

Abstract

Method (S1-S4) for operating a household appliance (1), the method having at least the following steps: - recording measured values relating to at least one component (4) of the household appliance (1) (S1); and- comparing the measured values and/or values derived therefrom with threshold values (S2) determined from component failure tests, wherein the measured values and/or the values derived therefrom include load values of the at least one component (4) and wherein a history of the load values, in particular a frequency, a duration and/or a size of the load values is recorded.

Description

The invention relates to a method for operating a household appliance, the method having at least one step of acquiring measured values relating to at least one component of the household appliance. The household appliance is set up to carry out the procedure.

EP 1 245 711 A1 discloses a method for operating a household appliance, in particular a washing machine or dishwasher, with a plurality of user-selectable sequentially executable programs, each program having at least one program-specific calculation rule to be applied to a key figure stored in a memory for determining a measure representing the degree of danger to a machine component is assigned, which is then stored in memory as a new key figure, with the execution of a program being modified if the measure exceeds or falls below a threshold value. To protect the device, it can be provided that if the threshold value is exceeded or fallen short of or is reached, the speed or working duration of a machine component is limited and/or the machine function is blocked and/or a heating or cooling element is switched on or off. Alternatively or additionally it can be provided that in this case a signal is given to the user and/or to a control device of the machine. The process can be used with washing machines or dishwashers that can run a variety of different programs. It is disclosed to classify the individual programs or program parts into those with positive, neutral, negative and indifferent effects on a component of the household appliance. It is possible to take the risk of different machine components into account by providing a corresponding component-specific key figure for each machine component. The disadvantage of this process is that manufacturing tolerances, manufacturing errors and environmental conditions are not taken into account.

In the DE 101 20 199 B4 describes a method for controlling a washing program of a washing machine, wherein the washing program is monitored.

In the DE 10 2004 034 193 A1 A method for controlling a dewatering operation of a washing machine is described.

In the DE 34 16 639 A1 a method for controlling a spin program of a washing machine is described, the washing machine having an unbalance detection device.

In the DE 18 05 716 U describes a safety device for electrically heated devices, in particular electric stoves.

In the DE 10 2006 017 530 A1 A laundry care device is described which carries out a method for detecting unbalance parameters

In the GB 2 109 097 A A water heating device is described which has a water warmer and a temperature sensor for monitoring a heating process.

It is the object of the present invention to provide a particularly cost-effective household appliance with improved operational reliability.

This task is solved according to the features of the independent claims. Preferred embodiments can be found in particular in the dependent claims.

The task is solved by a method for operating a household appliance, the method having at least the following steps: (a) recording measured values relating to at least one component of the household appliance and (b) comparing the measured values and/or values derived therefrom with those determined from component failure tests Thresholds. The use of measured values makes it possible to predict a failure more accurately than with a general assumption of loads on the component for specific operating programs or operating program sections, which improves operational safety. A household appliance or at least one monitored component of it can also be designed for a medium (and not the maximum possible) average load, since a total failure of the monitored component can be detected at an early stage with a high degree of certainty.

The measured values can be measured directly on the relevant (monitored) component or indirectly at other locations, whereby conclusions are then drawn about the condition of the relevant component. For example, a torque on a drive shaft of a laundry drum of a laundry appliance (washing machine or washer-dryer) can be determined directly on the drive shaft by means of the Wiedemann effect, indirectly via a torque bushing connected to the drive shaft, or indirectly based on preliminary experimental tests from a (measured or set) speed and, if necessary. Rotation time of the laundry drum can be determined together with a measurement of a load on the laundry drum (derived torque). The measured values can therefore be any measured values which are suitable for determining a condition of the monitored component.

To compare derived values with the threshold values, the derived values can include a link between one or more measured values and other, unmeasured operating parameters (speed, set temperature, type of laundry, etc.). Different types of measured values can also be linked together.

Measured values of different types can generally come from different sources, for example from different measured value recording devices.

The measured values and/or the values derived therefrom include load values of the at least one component. Load values can be understood in particular to mean values of variables by means of which a component is externally loaded. This makes it possible to easily compare with component failure tests in which the component to be monitored has been exposed to known loads and a probable component failure is determined depending on the load parameters varied in the component failure tests (e.g. a moment and/or a torque, predetermined patterns of alternating load, etc .) was determined. Consequently, an improved failure prediction for the monitored component can be carried out based solely on measurements of loads applied to this component.

Furthermore, a history of the load values, in particular a frequency, a duration and/or a size of the load values, is recorded. This means that long-term loads in particular can be recorded precisely, even across operating programs or operating program sections that have been carried out several times.

It is a further embodiment that the measured values and/or the values derived therefrom include component characteristics (component-related characteristics, in particular mechanical characteristics) of the at least one component. The component characteristics can, for example, represent values of a deflection, a stress in the component and/or a torsion of the monitored component. This makes it possible to predict component failure even more precisely. The component characteristics can be determined load-dependent or load-independent. This makes it possible to detect imminent failure - even independently of the detection and evaluation of a load on the component.

The component failure tests can include at least one service life test. In a lifespan test, several identical components are usually subjected to long-term stresses that occur in typical operation (particularly cyclic loads) until the components fail. This means that an average failure of an at least essentially identical component can be predicted simply from its load (size, type, pattern, etc.) or load history. A threshold value can be determined, for example, from loads previously applied to the component, whereby the probability of failure of the component can increase significantly when the threshold value is reached or exceeded.

The measured values and/or values derived therefrom for comparison with threshold values determined from service life tests can be pure load values (measured with one or more measured value recording devices). This has the advantage that no component parameters such as deflection or torsion need to be determined and, if necessary, recording the measured values is simplified. Alternatively, load values and component characteristics can be used.

The component failure tests can alternatively or additionally include at least one fracture test. During a fracture test, a component to be examined is usually overloaded until it fails and at least one component parameter (deflection, twist or torsion, stress in the component, etc.) is recorded. The fracture test can also be carried out cyclically. In particular, a probable failure can be predicted from several tests depending on one or more different component parameters. The at least one component characteristic value can be determined depending on the load (depending on one or more load values), for example for pure deflection, pure twisting or mixed forms. The use of a fracture test as the component failure test has the advantage that a correlation of a failure case is already provided with reaching or exceeding a threshold value of at least one component characteristic value. Knowledge of a previous exposure is not necessary. A failure, in particular a break, of the monitored component may be inherent in a deflection or twisting of the component when a threshold value is reached or exceeded, since under the (maximum possible or measured) loads that can be imposed, this threshold value is unlikely to occur for a component that is not damaged and reaching or exceeding this means damage, in particular Crack formation or crack propagation, indicates that a weakened material is then present. This means that an extraordinary failure of the component can also be detected.

It is an embodiment intended for an even more precise prediction of the damage event that the measured values and/or the values derived therefrom include both component characteristics and load values of the at least one component. The at least one threshold value can thus be determined depending on at least one load parameter.

It is particularly advantageous for a reliable damage prediction if both aspects are used, i.e. a comparison of suitable measured values and/or values derived therefrom is carried out with threshold values determined from service life tests and with threshold values determined from fracture tests.

It is also an embodiment that after reaching or exceeding at least one of the threshold values, at least one associated message is output. This message may include at least one warning and/or at least one service message. The message can be displayed on a display unit of the household appliance. The message can alternatively or additionally be issued to a service point, e.g. a dealer or a manufacturer. For this purpose, the household appliance can have a communication device with an external network (e.g. Internet, telephone network, etc.).

It is also an embodiment that after reaching or exceeding at least one of the threshold values (from the service life tests and/or from the fracture tests), at least one load on the associated component is automatically reduced by the household appliance. In this way, the household appliance can be operated for an extended period of time, so that a user can continue to use the household appliance, even if only to a limited extent, until the corresponding component is replaced or repaired. For example, after an (accumulated) load on a drive shaft has been reached and/or after cracking has been detected, a maximum usable speed can be reduced and a warning of overloading can be issued with a reduced load weight.

The task is also solved by a household appliance, wherein the household appliance is designed and set up to carry out the method and has at least one measured value acquisition device for recording the measured values and an evaluation and comparison device, in particular a control device, for comparing. The control device can be equipped with or coupled to at least one memory for storing the threshold values and/or a load history of at least one component.

The household appliance can be, for example, a laundry treatment device or a dishwasher. The laundry treatment device can in particular be a laundry device for washing laundry, for example a washing machine or a washer-dryer.

The laundry appliance can in particular have an oscillatable tub, in which a laundry drum rotatable about a substantially horizontal axis for receiving laundry is arranged, as well as a drive motor for driving the laundry drum via a drive shaft. The drive shaft is rotatably mounted in a pivot bearing.

The laundry appliance can also have a speed control device, which outputs a control variable for adjusting a speed of the drive motor and to which, in particular, a feedback variable dependent on the speed of the laundry drum is supplied. The laundry appliance can also include a program control that controls a spin cycle, by means of which the laundry drum is accelerated to at least one spin speed by activating the drive motor. The speed control device and the program control can, for example, be integrated in the control device.

It is a special embodiment that the at least one component to be monitored is the drive shaft.

• 1 zeigt als Schnittdarstellung in Seitenansicht ein erfindungsgemäßes Haushaltsgerät in Form einer Waschmaschine;
• 2 zeigt als Schnittdarstellung in Seitenansicht eine detailliertere Ansicht der Waschmaschine im Bereich einer Antriebswelle; und
• 3 zeigt ein Ablaufdiagramm eines erfindungsgemäßen Verfahrens auf dem erfindungsgemäßen Haushaltsgerät.

In the following figures, the invention is described schematically in more detail using an exemplary embodiment. For clarity, elements that are the same or have the same effect can be provided with the same reference numerals. Features of the preferred embodiments of the method according to the invention can be used in the household appliance according to the invention. Within the scope of the invention, these features can also be combined with one another in any way.

• 1 shows a sectional view in side view of a household appliance according to the invention in the form of a washing machine;
• 2 shows a sectional side view of a more detailed view of the washing machine in the area of a drive shaft; and
• 3 shows a flowchart of a method according to the invention on the household appliance according to the invention.

1 shows a laundry appliance in the form of a washing machine 1. The washing machine 1 has a laundry drum 2 which can be rotated about a substantially horizontal axis and which is rotatably housed in a oscillatable tub 3. The tub 3 holds lye L for washing laundry W located in the laundry drum 2. The laundry drum 2 is driven by means of a rear drive shaft (drum shaft) 4, which is rotatably mounted in a pivot bearing 5, the drive shaft 4 in turn being driven by a drive motor 6.

The washing machine 1 also has a control device 7 for carrying out at least one operating program or operating program section. The control device 7 is set up, among other things, to output a control variable for setting a speed of the drive motor 6. The washing machine 1 can also include a program control that controls a spin cycle, by means of which the laundry drum 2 is accelerated to at least one spin speed by controlling the drive motor 6. The lye L is pumped out for the spin cycle.

A measured value acquisition device 8 is provided on the drive shaft 4 in order to record load values acting on the drive shaft (e.g. a moment or a torque) and/or component characteristics of the drive shaft (e.g. a tension, a deflection and/or a rotation around its longitudinal axis (torsion)). to determine. The control device 7 can convert the measured values into values derived therefrom. The control device 7 can also convert component characteristics into load values, or vice versa. The control device 7 has a memory 10 in which threshold values for carrying out the in 3 are stored using the procedure described. The washing machine 1 is generally designed to carry out this method.

The control device 7 is coupled to a display unit 11 for issuing, among other things, warnings.

2 shows a sectional view in side view of a more detailed view of the washing machine in the area of the drive shaft 4. The pivot bearing 5 is designed as a ball bearing which is held by a ball bearing seat 12. The drive shaft 4 is connected to the drive motor (not shown) via a pulley 13.

A cross-hatched area 14 of the drive shaft 4 has a magnetostrictive material, the magnetic field of which can be detected by means of the measured value acquisition device 8 designed as a magnetic field sensor or magnetometer. Due to the magnetostrictive nature, a stress or deformation acting on the area 14 can be detected by the Villari effect or, in the case of a twist, by the Wiedemann effect by a change in the magnetic field. From this, a deformation and/or twist (as component parameters) and/or an applied moment or torque (as load parameters) can be determined.

3 shows a flowchart of a method for operating the washing machine 1.

In a first step S1, measured values recorded by the measured value acquisition device 8, which relate to the drive shaft 4, are recorded, namely a deformation and/or rotation (as component parameters) and/or an applied moment or torque (as load parameters) of the drive shaft in the area 14.

In a second step S2, these measured values are compared with threshold values determined from component failure tests, in particular by means of the control device 7.

For example, the measured values can be values of at least one of the component parameters recorded at regular time intervals, here for example a torsion. It is one possibility to use a threshold value determined from a fracture test, which should not occur regardless of the load (i.e. under no typically applied loads) if the drive shaft 4 is undamaged. If the torsion reaches the threshold value, this is an indication of a weakening of the drive shaft, in particular due to crack formation or crack propagation.

Alternatively or additionally, a value of a component parameter can be used to detect at least one associated load variable, for example a torsion of the drive shaft 4 as a function of an applied torque. An abnormally increased torsion for a certain torque can indicate crack formation or crack propagation, whereby a torque-dependent torsion threshold value for the presence of a hazard or an immanent failure of the component was determined from a fracture test and can be applied here.

Alternatively or additionally, only load characteristics are recorded and stored (in particular accumulated) in the memory 10 and compared with a threshold value for a load on the drive shaft 4 determined from service life tests.

In a third step S3, when the threshold value or threshold values are reached or exceeded (from above or below), a message is output, for example to the display unit 11 or to a service center.

With the third step S3, a fourth step S4 can be carried out, in which the control device 7 places a lower load on the drive shaft 4, in particular operates the laundry drum 2 at a lower speed in order to delay failure of the drive shaft 4.

Of course, the present invention is not limited to the exemplary embodiments shown.

This means that other components can also be monitored. Additional or other measured values or values derived from them may also be used. In particular, other measured value acquisition devices can also be used alternatively or additionally, for example a load sensor and/or a temperature sensor.

Reference symbol list

1

washing machine

2

laundry drum

3

Lye container

4

drive shaft

5

Pivot bearing

6

drive motor

7

Control device

8th

Measurement recording device

10

Storage

11

Display unit

12

Ball bearing seat

13

pulley

14

Area with magnetostrictive material

L

Lye

S1

first step of the process

S2

second procedural step

S3

third step of the process

S4

fourth step of the process

W

Laundry

Claims (8)

Method (S1-S4) for operating a household appliance (1), the method having at least the following steps: - Recording measured values relating to at least one component (4) of the household appliance (1) (S1); and - Comparing the measured values and/or values derived therefrom with threshold values (S2) determined from component failure tests, wherein the measured values and/or the values derived therefrom include load values of the at least one component (4) and wherein a history of the load values, in particular a frequency, is provided Duration and/or a size of the load values is recorded. Procedure (S1-S4). Claim 1 , wherein the measured values and/or the values derived therefrom include component characteristics of the at least one component (4). Procedure (S1-S4). Claim 1 or 2 , wherein at least one component failure test includes at least one service life test. Method (S1-S4) according to one of the preceding claims, wherein at least one component failure test comprises at least one fracture test. Method (S1-S4) according to one of the preceding claims, wherein at least one associated message is output (S3) after at least one of the threshold values has been reached or exceeded. Method (S1-S4) according to one of the preceding claims, wherein after reaching or exceeding at least one of the threshold values, at least one load on the associated component (4) is automatically reduced by the household appliance (1) (S4). Household appliance (1), in particular washing machine, wherein the household appliance (1) is set up to carry out the method according to the preceding claims and at least one measured value recording device (8) for recording the measured values and an evaluation and comparison device, in particular control device (7), for comparing having. household appliance (1). Claim 7 , wherein the household appliance (1) is a washing machine and the at least one component (4) comprises a drum shaft.

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