DE102017202774B3 - Household appliance with an electromagnetic door lock - Google Patents

Abstract

A household appliance (100) having a door (101) and an electromagnetic door lock (103) for closing the door (101), wherein the electromagnetic door lock (103) comprises an electromagnetic coil (105) and a movable coil core (107), characterized by a Measuring circuit (300) which is electrically connected to the electromagnetic coil (105) and configured to apply an electrical measurement signal to the electromagnetic coil (105) and to detect an electrical response signal in response to the measurement signal for vibration detection in the household appliance (100) ,

Description

The present invention relates to vibration detection in a household appliance.

Mechanical vibrations in household appliances such as washing machines or dishwashers can lead to an impairment of the functioning of the household appliance. For detecting vibrations in a household appliance can be efficiently used in the DE102007028739 B4 revealed magnetic field sensor are used.

The publication DE 10 2014 204 606 A1 describes a household appliance with a door lock mechanism.

The publication DE 100 07 839 A1 describes a vibration detecting device.

It is the object of the present invention to provide an alternative concept for vibration detection in a household appliance.

This object is solved by the features of the independent claims. Advantageous forms of further development are the subject of the accompanying figures, the description and the dependent claims.

The present invention is based on the finding that in modern household appliances such as washing machines or dishwashers for closing or locking a door is often installed an electromagnetic door lock with an electromagnetic coil and a movable coil core. By applying a locking signal to the electromagnetic coil, an electromagnetic field is generated which attracts the movable spool core, whereby the door can be locked. According to the invention, the electromagnetic door lock is used for the particularly cost-effective detection of vibrations in the household appliance. This is based on the further realization that, in vibration in the household appliance, the movable coil core dives into the electromagnetic coil due to vibration, which leads to a change in an electrical property of the coil, in particular an inductance and thus an inductive reactance, which is related to the oscillation , This change can be detected by applying the coil with a separate measurement signal different from a lock signal to the door lock for vibration detection.

According to a first aspect, the invention relates to a household appliance having a door and an electromagnetic door lock for locking the door, wherein the electromagnetic door lock comprises an electromagnetic coil and a movable coil core having a measuring circuit which is electrically connected to the electromagnetic coil and is configured to apply an electrical measurement signal to the electromagnetic coil and to detect an electrical response signal in response to the measurement signal for vibration detection in the household appliance.

Thereby, the technical advantage is achieved that is realized by the measuring circuit with the electromagnetic door lock the function of an inertial sensor for detecting mechanical vibrations, in particular vibrations. In the household appliance can thus be dispensed with an additional, for example, attached to an electric motor of the household appliance, inertial sensor, so that manufacturing costs and manufacturing costs of the household appliance can be advantageously reduced.

The response signal of the measuring circuit can, for example, image the vibrations of a tub of a washing machine, the spray arms of a dishwasher or the laundry drum of a tumble dryer. Furthermore, it is possible to detect externally acting on the household appliance vibrations. These may be, for example, vibrations of a further domestic appliance, which is mechanically coupled to the household appliance, wherein the further domestic appliance is arranged in particular next to, on or below the household appliance.

In one embodiment, the electromagnetic door lock is activatable by an electrical lock signal, wherein the electrical measurement signal and the electrical lock signal are different.

As a result, the advantage is achieved that the function of the electromagnetic door lock as a vibration sensor does not affect the closing or locking function of the electromagnetic door lock.

The lock signal may be an electric current flowing through the electromagnetic coil. As a result, a magnetic field is generated by the electromagnetic coil. The bobbin may be ferromagnetic so that it is attracted to the electromagnetic coil. A slider connected to the spool core may then change position and activate a mechanical door lock mechanism. The spool core can be held in position by a needle so that mechanical locking of the door is realized even without the locking signal applied to the electromagnetic coil.

In one embodiment, the measuring circuit is configured to generate the electrical measuring signal with an electrical power which is lower than an electrical power, which is necessary for actuating the movable coil core by means of the electromagnetic coil.

As the measuring signal can advantageously be used an AC signal having a lower electrical power than for the operation, in particular for locking and / or unlocking the door, the electromagnetic door lock is necessary. Thus, the advantage can be achieved that vibrations of the coil core can be measured without affecting the function of closing or locking the door of the electromagnetic door lock.

In one embodiment, the measurement circuit has a signal generator which is designed to generate the measurement signal.

The signal generator can be designed to generate an alternating voltage signal as a measuring signal, so that a periodically alternating magnetic field is generated by the electromagnetic coil. This magnetic field can enforce the coil core, so that vibrations of the household appliance and thus vibrations of the coil core can lead to changes in the measurement signal.

The periodic oscillation of the measuring signal can be constantly applied to the coil and thus does not change, for example. The current intensity and the phase of the imaginary part of the measurement signal change, which in the illustrated embodiment leads to the response signal as a voltage drop across the resistor.

With the measurement signal of the signal generator, the measurement circuit forms the response signal, which may differ in amplitude and in phase from the measurement signal of the signal generator, but may have the same frequency.

In one embodiment, the measurement circuit has a resistor connected in series with the electromagnetic coil, and wherein the measurement circuit is configured to detect the response signal at the resistor, in particular as a voltage value across the resistor.

The inductance of the electromagnetic coil can be measured indirectly, for example via the voltage drop across a resistor.

The measuring signal may be an alternating voltage, so that the reactance of the measuring circuit may change with an inductance change of the electromagnetic coil. This change can be measured by changing the voltage dropped across the resistor so that this voltage change can be measured instead of the inductance change. Therefore, the measurement circuit can be realized cost-effectively, since an inductance measurement via a voltage measurement compared to a measurement of the phase shift can be realized more cheaply.

In a further embodiment, the inductance can be measured with a measuring bridge with the electromagnetic coil in a circuit branch and a further coil in a further circuit branch. The voltage difference between the branches can be indicated by the response signal as a function of the inductance of the electromagnetic coil. The dependence of the response signal on the inductance of the coil can be linear, for example, proportional.

In one embodiment, the response signal between the branches is phase-shifted with respect to the measurement signal, so that the variable inductance of the electromagnetic coil in a circuit branch is only partially depicted in the response signal.

In one embodiment, the inductance can be detected by a phase shift of the response signal relative to the measurement signal.

In one embodiment, the resistor and the electromagnetic coil form a series circuit, wherein the measuring circuit is designed to apply the measurement signal to the series circuit, in particular to external terminals of the series circuit.

Above the resistor connected in series with the electromagnetic coil, a voltage drops, which may depend on the current flowing through the electromagnetic coil. Advantageously, it is thus possible to measure the change in the measuring signal by oscillations of the household appliance via the voltage dropping across the resistor at the resistor. By applying the measurement signal to external terminals of the series connection, the advantage is achieved that the electromagnetic coil and the resistance are traversed by the measurement current of the measurement signal.

In one embodiment, the measuring circuit comprises a signal sensor, in particular a voltmeter or a frequency meter, for detecting the response signal.

As a result, the advantage is achieved that the response signal generated by the measuring circuit can be detected and forwarded or processed. The voltage drop across the resistor can form the response signal, which can be detected by the signal receiver in the form of a voltmeter. The electromagnetic coil and the coil core arranged movably therein form a plunger-armature transducer, wherein the coil core can form the plunger armature. Thus, mechanical vibrations of the spool core can be converted into electromagnetic oscillations in the electromagnetic coil, which can be detected for example by a frequency meter.

The movement of the spool core may be possible by an interference fit and / or dimensional and / or shape tolerances of the electromagnetic door closure. In addition, the coil core in its installed position can be set back by gravity, which can be advantageous for detecting mechanical vibrations through the coil core.

In one embodiment, the measuring circuit is configured to detect a response signal value of the response signal, in particular an absolute value or a maximum value or a frequency of the response signal, and to detect at least one oscillation in the domestic appliance on the basis of the signal value.

As a result, the advantage is achieved that the measuring circuit can detect a response signal value which correlates with the mechanical vibrations acting on the domestic appliance. Thus, the mechanical vibrations are not only converted from a mechanical signal into an electrical signal, but also advantageously detected this signal as a response signal, which can be used for further processing or evaluation.

In one embodiment, the response signal value depends on a vibration-induced change in inductance of the electromagnetic coil due to the vibration in the home appliance, the measurement circuit being configured to detect the vibration by detecting the response signal value.

In one embodiment, the response signal value depends on a vibratory insertion depth or immersion frequency of the movable spool core into the electromagnetic coil, wherein the sensing circuit is configured to detect a vibration amplitude or vibration frequency based on the response signal value.

In one embodiment, the measuring circuit is designed to compare the detected vibration, in particular a vibration amplitude or an oscillation frequency, with a reference vibration, in particular with a reference amplitude or with a reference frequency, and to detect a vibration anomaly on the basis of a comparison result.

As a result, the advantage is achieved that periodic movements, in particular rotations of mechanical components of the household appliance can be monitored. If the oscillation detected by the measuring circuit does not deviate from the reference oscillation or only within predetermined tolerances, it is possible to conclude that the domestic appliance is in proper operation. In the case of deviations from the reference oscillation outside given tolerance ranges, the response signal provided by the measuring circuit can thus be an indication of a deviation from that provided by the manufacturer. Operating parameters of the household appliance. This deviation can be generated for example by changing the bearing of a rotating component, a modified shock absorber or a modified electric motor of the household appliance. Furthermore, a deviating from the reference vibration response signal can be generated by a mechanical change of the electromagnetic door closing.

In an embodiment, the measurement circuit is configured to generate an indication signal indicative of a detected vibration property.

As a result, the advantage is achieved that the response signal is mapped to a reduced display signal. For example, the maximum vibration amplitude, the vibration amplitude average, the vibration frequency or the vibration frequency dispersion is generated as the indication signal.

In one embodiment, the measuring circuit is designed to transmit the indication signal via a communication network, in particular to a service server. This allows the service server to be informed of a state of the household appliance.

As a result, the advantage is achieved that errors can be detected without manual control and can be detected and processed by an external body, such as a service server. By continuous emission of the display signal, a change over time of the display signal can be detected, so that, for example, conclusions on wear or wear of components of the household appliance are possible and a change in the operating parameters of the household appliance can be anticipated and thus timely maintenance can be done.

In one embodiment, the household appliance according to claim comprises an optical or acoustic display, wherein the measuring circuit is configured to display the display signal by means of the display.

As a result, the advantage is achieved that an acoustically or visually perceptible indicator for a characteristic of the vibration of the household appliance is realized directly on the device, so that the status of the household appliance with respect to the vibration is directly verifiable.

According to a second aspect, the invention relates to a method for vibration detection in a domestic appliance having an electromagnetic door lock for closing a door of the household appliance, wherein the electromagnetic door lock comprises an electromagnetic coil and a movable coil core, comprising the steps of: applying the electromagnetic coil to a electrical measuring signal by a measuring circuit; and detecting an electrical response signal in response to the measurement signal by the vibration detection measurement circuit.

This method of vibration detection can be used in addition to household appliances in other devices or machines. For example, in a vehicle, an electromagnetic coil disposed in the vicinity of the engine can absorb engine vibrations with a spool core.

Further process features emerge directly from the features of the household appliance according to the first aspect.

• 1 ein Haushaltsgerät gemäß einer Ausführungsform;
• 2 einen Teil eines elektromagnetischen Türverschlusses gemäß einer Ausführungsform; und
• 3 eine Messschaltung gemäß einer Ausführungsform.

Further embodiments of the invention will be explained in more detail with reference to the accompanying drawings. Show it:

• 1 a household appliance according to an embodiment;
• 2 a portion of an electromagnetic door closure according to one embodiment; and
• 3 a measurement circuit according to an embodiment.

1 shows a schematic representation of a general household appliance 100 , such as a washing machine. The household appliance 100 includes a door 101 for loading the household appliance 100 , The door 101 closes a device opening on a side surface of the household appliance 100 , Furthermore, the household appliance includes 100 an electromagnetic door lock 103 to close the door 101 , which laterally of the circular door 101 is arranged. The door 101 is centered in a side surface of the cuboid shaped household appliance 100 arranged.

2 shows a schematic representation of a cross section of the electromagnetic door closure 103 with an electromagnetic coil 105 and a movable spool core 107 and one pusher 106 , The movable spool core 107 is at least partially in the tubular electromagnetic coil 105 arranged so that coincides with the relative position of the bobbin 107 with respect to the electromagnetic coil 105 , the inductance of the electromagnetic coil 105 changes. The coil core 107 is cylindrical in shape and has an end which is not the electromagnetic coil 105 passes through a coil core edge, which compared to the inner diameter of the tubular electromagnetic coil 105 has a larger diameter. The bobbin edge is from the slider 106 at least partially. The slider 106 can with the door 101 be connected and a lock or unlock the door 101 cause.

In one embodiment, the electromagnetic coil 105 formed by two symmetrically wound side by side coils, so that a higher sensitivity to an altered inductance of the electromagnetic coil 105 is realized. In this embodiment, by countersinking the spool core 107 into the electromagnetic coil 105 the inductances in the coils wound side by side changed in opposite ways. The mutual compensation of the coils can cause high temperature stability. The circuit complexity for measured value output is also low in this embodiment.

Another advantage of the inductive measurement is the possibility of a non-contact measurement, so that only the coil core 107 in mechanically coupled connection with the oscillating component of the household appliance 100 must be to realize a measurement of the vibration.

In one embodiment, the spool core 107 cylindrical, wherein the outer diameter of the spool core 107 the inner diameter of the tubular electromagnetic coil 105 equivalent. Thus, the coil core can 107 the space inside the electromagnetic coil 105 fully enforce. The coil core 107 can oscillate along its longitudinal axis in this arrangement. The inductance of the electromagnetic coil 105 can come up with the displacement of the spool core 107 along the longitudinal axis of the spool core 107 change as long as the bobbin core 107 from the magnetic field of the electromagnetic coil 105 is detected.

In one embodiment, the absolute immersion depth of the spool core 107 into the electromagnetic coil 105 with the measuring circuit 300 determinable.

In one embodiment, the home appliance 100 a loadable chamber, such as a laundry drum or a crockery container, wherein the mechanical vibrations of the household appliance may be changed by the degree of loading of the loadable chamber. These vibration changes can be caused by the vibration of the spool core 107 be pictured and thus can with the measuring circuit 300 be measurable.

In one embodiment of mechanical vibrations, which of the coil core 107 are recorded on the sound output of the household appliance 100 getting closed.

3 shows a schematic representation of the measuring circuit 300 , with a signal generator 109 a resistance 111 , the electromagnetic coil 105 and a signal receiver 113 , The resistance 111 , the electromagnetic coil 105 are arranged electrically in series and the signal receiver is electrically parallel to the resistor 111 arranged. The signal generator 109 is electrically parallel to the resistor 111 and the electromagnetic coil 105 arranged.

In one embodiment, the signal generator 109 For example, generate an alternating voltage with an amplitude in the range of 1 V to 300 V and a frequency in the range of 100 Hz to 20 kHz. That of the signal generator 109 generated measurement signal and the resistance R _mes are advantageously chosen so that the expected amplitude difference of the response signal, which by vibrations of the household appliance 100 is generated in proportion to the amplitude of the response signal is maximum. The amplitude difference ΔU _Rmax can be _determined , for example, by the following formula: $$\begin{array}{c}\mathrm{\Delta }{\widehat{U}}_{Rmax}\left(\mathrm{\Delta }s\right)=R_{mes}\cdot u_z\cdot \\ \left(\frac{1}{\sqrt{2\cdot R^2+{\left(4\cdot \pi \cdot f\cdot \left(\frac{\left(L_{max}-L_{\text{min}}\right)\cdot s}{s_{max}}+L_{\text{min}}\right)\right)}^2}}-\frac{1}{\sqrt{2\cdot R^2+{\left(4\cdot \pi \cdot f\cdot \left(\frac{\left(L_{max}-L_{\text{min}}\right)\cdot \left(s+\mathrm{\Delta }s\right)}{s_{max}}+L_{\text{min}}\right)\right)}^2}}\right)\end{array}$$

The measuring resistor R _mes can have an ohmic resistance in the range from 1 mΩ to 20 kΩ. L _max and L _min denote the maximum and the minimum inductance corresponding to the maximum and minimum immersion depth s of the spool core 107 into the electromagnetic coil 105 , The maximum immersion depth of the spool core 107 For example, s _max = 6 mm. The minimum inductance L _min may be about 70 mH and the maximum inductance L _max may be about 120 mH. In the closed state of the door lock 103 can the immersion depth of the spool core 107 for example, s = 0 mm. When changing the immersion depth .DELTA.s of the spool core 107 due to vibrations in the household appliance 100 of about 0.2 mm, the amplitude difference of the response signal .DELTA.U _{Rmax can be} about two percent of the amplitude of the measurement signal according to the above formula.

All features explained and shown in connection with individual embodiments of the invention may be provided in different combinations in the article according to the invention, in order to simultaneously realize their advantageous effects.

The scope of the present invention is given by the claims and is not limited by the features illustrated in the specification or shown in the figures.

LIST OF REFERENCE NUMBERS

100

household appliance

101

door

103

electromagnetic door lock

105

electromagnetic coil

106

pusher

107

Plunger

109

signal generator

111

resistance

113

signal sensor

300

measuring circuit

Claims (15)

A household appliance (100) having a door (101) and an electromagnetic door lock (103) for closing the door (101), wherein the electromagnetic door lock (103) comprises an electromagnetic coil (105) and a movable coil core (107), characterized by a Measuring circuit (300) which is electrically connected to the electromagnetic coil (105) and configured to apply an electrical measurement signal to the electromagnetic coil (105) and to detect an electrical response signal in response to the measurement signal for vibration detection in the household appliance (100) , Household appliance (100) after Claim 1 wherein the electromagnetic door lock (103) can be activated by an electrical lock signal, characterized in that the electrical measurement signal and the electrical lock signal are different. Household appliance (100) after Claim 1 or 2 , characterized in that the measuring circuit (300) is designed to generate the electrical measuring signal with an electrical power which is less than is an electric power, which is necessary for the actuation of the movable spool core (107) by means of the electromagnetic coil (105). Domestic appliance (100) according to one of the preceding claims, characterized in that the measuring circuit (300) has a signal generator (109) which is designed to generate the measuring signal. Domestic appliance (100) according to one of the preceding claims, characterized in that the measuring circuit (300) has a resistor (111) which is connected in series with the electromagnetic coil (105), and wherein the measuring circuit (300) is formed, the Response signal to the resistance (111), in particular as a voltage value across the resistor (111) to detect. Domestic appliance (100) according to any one of the preceding claims, characterized in that the resistor (111) and the electromagnetic coil (105) form a series circuit, wherein the measuring circuit (300) is formed, the measurement signal to the series circuit, in particular to external terminals of Series connection to create. Domestic appliance (100) according to one of the preceding claims, characterized in that the measuring circuit (300) has a signal sensor (113), in particular a voltmeter or a frequency meter, for detecting the response signal. Domestic appliance (100) according to one of the preceding claims, characterized in that the measuring circuit (300) is designed to detect a response signal value of the response signal, in particular an absolute value or a maximum value or a frequency of the response signal, and at least one oscillation in the domestic appliance ( 100) based on the signal value. Household appliance (100) after Claim 8 characterized in that the response signal value depends on a vibration-induced change in inductance of the electromagnetic coil (105) due to the vibration in the home appliance (100), and in that the measurement circuit (300) is adapted to detect the vibration by detecting the response signal value. Household appliance (100) after Claim 8 or 9 characterized in that the response signal value depends on a vibration-induced immersion depth or immersion frequency of the movable spool core (107) into the electromagnetic coil (105), and in that the measurement circuit (300) is formed on the basis of the response signal value, a vibration amplitude or a vibration frequency of the vibration capture. Domestic appliance (100) according to any one of the preceding claims, characterized in that the measuring circuit (300) is adapted to compare the detected vibration, in particular a vibration amplitude or a vibration frequency, with a reference vibration, in particular with a reference amplitude or with a reference frequency, and to detect a vibration anomaly on the basis of a comparison result. Household appliance (100) according to one of the preceding claims, characterized in that the measuring circuit (300) is adapted to generate an indication signal indicative of a characteristic of a detected vibration. Household appliance (100) after Claim 12 , characterized in that the measuring circuit (300) is adapted to emit the display signal via a communication network, in particular to a service server. Household appliance (100) after Claim 12 or 13 , having an optical or acoustic display, characterized in that the measuring circuit (300) is adapted to display the display signal by means of the display. A method of vibration detection in a domestic appliance (100) comprising an electromagnetic door lock (103) for closing a door (101) of the household appliance (100), wherein the electromagnetic door lock (103) comprises an electromagnetic coil (105) and a movable coil core (107 ), characterized by Applying an electrical measurement signal to the electromagnetic coil (105) by a measuring circuit (300); and detecting an electrical response signal in response to the measurement signal by the vibration detection measurement circuit (300).

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