DE102013215846A1 - Household appliance with sound output unit - Google Patents

Abstract

The domestic appliance (1) has at least one electric motor, in particular a brushless DC motor (2) which can be driven by means of an electrical drive signal (ATS, mATS, mATS2), and at least one sound output unit which generates at least one acoustic sound signal based on at least one electrical tone generation signal (TES) Signal generated on, wherein at least one electric motor (2) also serves as a sound output unit in that the drive signal (ATS) by means of the at least one tone generation signal (TES) is modulated.

Description

The invention relates to a domestic appliance, comprising at least one electric motor, which can be driven by means of electrical drive signals, and having at least one sound output unit, which generates acoustic signals based on electrical sound generation signals.

They are household appliances of the type in question, in which the sound output unit is a loudspeaker or a buzzer which plays tone sequences or melodies upon the occurrence of certain operating conditions (for example, an end of an operating program or an error).

It is the object of the present invention to overcome the disadvantages of the prior art at least partially, and in particular to provide a simplified and cost-effective way to output even complex sounds and sound sequences.

This object is achieved according to the features of the independent claims. Preferred embodiments are in particular the dependent claims.

The object is achieved by a household appliance, comprising at least one electric motor, which is drivable by means of at least one electrical signal (hereinafter referred to as "drive signals" hereinafter), and at least one sound output unit based on electrical signals (hereinafter without limitation commonly referred to as "tone generation signals") generates audible signals, wherein at least one electric motor also serves as a sound output unit by allowing the (original) drive signal to be modulated or varied by means of the at least one tone generation signal. In other words, the domestic appliance is set up to modulate the drive signal of the electric motor with the aid of the at least one tone generation signal such that the electric motor can also serve as a sound output unit. This has the advantage that it can be dispensed with a separate buzzer or speaker, which allows the simplified and cost-effective way to output even complex sounds and sound sequences. Another advantage is a fallback to generate acoustic signals in case of failure of the speaker or buzzer.

In this household appliance is exploited that cause an electric motor generated by the at least one tone generation signal current changes in the coils, a change in the magnetic field strength and thus a mechanical movement of the rotor or stator of the motor. These movements create sound waves. As a resonant body, for example, the electric motor itself, a motor shaft, an associated rotatable functional part (a fan, etc.) and any other element that has a mechanical connection with the electric motor, act.

Characterized in that the drive signal can be modulated or modulated by means of the at least one tone generation signal, tones and tone sequences can thus be generated in particular even when the electric motor is running. This considerably expands the possibilities of application for sound output.

The fact that the drive signal can be modulated or varied by means of the at least one tone generation signal may include in particular that a modulated drive signal can be generated or generated instead of the original drive signal.

It is an embodiment that the electric motor is a brushless electric motor. The use of a brushless electric motor has the advantage that a rotational movement of a drive shaft can be selectively prevented even at higher currents, by not applying a rotating field. As a result, a rotational movement of the brushless electric motor can be at least partially decoupled from its current supply (for example by generating the drive signal), so that it can be controlled in an optimized manner to generate acoustic signals without this needing to be expressed in a disadvantageous rotational movement. In addition, in brushless electric motors usually due to their electronic commutation already an electronics available, which can be used for tone generation. The brushless electric motor may be a brushless DC motor or a brushless AC motor.

However, the electric motor may basically also be a brush motor, e.g. a DC motor or an AC motor.

It is a further development that the at least one tone generation signal comprises at least one analog electrical signal which generates the desired acoustic signal or the desired tones (including tone sequences and / or speech) when applied to the electric motor. In particular, these analog tone generation signals may have a frequency in the audible range.

The electrical drive signal may be a continuous electrical signal or a series of a plurality of individual electrical signals (e.g., a train of pulses).

It is still an embodiment that the drive signal of the electric motor is a pulse width modulated signal ("PWM signal"). The PWM signal is particularly easy to generate, since electric motors, in particular brushless DC motors, can already have such a PWM-based motor control. In particular, the PWM signal may represent a periodic sequence of pulse width modulated pulses of equal width. In order to make a rotational movement, for example, by a brushless DC motor, a rotating field is applied to its coils whose power and thus usually speed is controlled by the pulse width modulation or a change or variation of the width or width of the applied pulses: the wider the pulses are, the higher the force or the speed. In particular, the frequency of the PWM should be much higher than a rotating field frequency in order to ensure the current flow order of the coils. For example, in most BLDC motors, the PWM frequency is between 15 kHz and 30 kHz.

By modulating this PWM drive signal with a tone generation signal, an audible signal can be generated in the audible range. The fact that the PWM drive signal can be modulated or varied by means of the at least one tone generation signal may include in particular that instead of an original pulse sequence, a correspondingly modulated or changed pulse sequence can be generated or generated. In particular, a pulse density modulation, a frequency modulation, a pulse width modulation and / or a pulse pause or pulse width pause modulation are suitable as modulation. Also, a delta modulation may be applied.

Thus, it is a further embodiment that the (original) drive signal is pulse-duration-modulated by means of the at least one tone generation signal. Instead of the original PWM drive signal, therefore, a drive signal which is pulse-width modulated by means of the at least one tone generation signal is generated in particular. At this time, the pulse width or pulse width of a pulse of the original PWM drive signal is changed in accordance with a magnitude, particularly amplitude, of the tone generation signal at the time of the pulse (for example, at the time of starting the pulse). For example, the pulse duration may be increased in an amplitude-dependent manner if the strength, in particular amplitude, of the tone generation signal is above a predetermined threshold (e.g., zero) and is amplitude-reduced, if the magnitude, in particular amplitude, of the tone generation signal is below this threshold. As the pulse duration is changed, the magnitude of the current flowing through the coils also changes, which can produce acoustic signals. This refinement has the advantage that the pulse duration in PWM-controlled electric motors can be changed without further effort.

It is also an embodiment that the drive signal by means of the at least one tone generation signal is pulse density modulated. Instead of the original PWM drive signal, in particular, a pulse signal-modulated drive signal is generated by means of the at least one tone generation signal. At this time, the density or number of a series of pulses of the original PWM drive signal corresponding to a magnitude, in particular amplitude, of the tone generation signal at the time of the pulse (e.g., at the time of starting the pulse) is changed, in particular reduced. For example, the pulse duration may be increased in an amplitude-dependent manner if the strength, in particular amplitude, of the tone generation signal is above a predetermined threshold value (eg zero) and the number or density of the pulses are reduced or reduced as a function of amplitude, if the strength, in particular the amplitude, of the pulse Sound generation signal is below this threshold. With changed pulse duration and pulse density, the strength of the current flowing through the coils also changes, which may produce acoustic signals. This embodiment also has the advantage that the pulse duration in PWM-controlled electric motors can be changed without further effort, e.g. by assigning individual pulses a greater width or width or a width zero.

It is also an embodiment that the drive signal by means of the at least one tone generation signal is Pulspausenmodulierbar.

It is also an embodiment that the drive signal by means of the at least one tone generation signal is frequency modulated. The frequency modulation is easy to implement, since many motor controls are provided to vary the pulse rate. It is amplitude-dependent not the pulse duration varies, but the pulse rate. In particular, the pulse rate may be increased to higher magnitude, in particular amplitude, of the at least one tone generation signal (ie, the pitches between adjacent pulses are reduced) and decreased to lesser magnitude, in particular amplitude, of the at least one tone generation signal. Also by the frequency modulation, a recognizable acoustic signal is output to the electric motor, in particular brushless DC motor.

If the electric motor, in particular brush motor, should not be in operation, the pulse duration may be set so low that the DC motor or a functional part driven by it (eg a fan wheel) are still operated, but with such a low amperage or speed that thereby a function of the household appliance is not affected. For example, an electric motor for driving a circulating air fan may be operated at such a low speed that a thus generated air flow is practically negligible.

Alternatively or additionally, the modulation pulses of the original drive signal can be based on a pulse duration which reliably enables clear output of acoustic signals. This takes into account that a duration of acoustic signals is usually low and therefore the electrical signals do not require continuous operation of the electric motor. The effect of the output of acoustic signals via the otherwise not operated electric motor for the drive function is usually negligible. It plays e.g. Also, the inertia of the driven components (e.g., a fan wheel) plays a role. The drive motor may also be operated only for the output of acoustic signals, while its drive function is not used.

When using a brushless electric motor, however, it is possible to decouple the current flowing through the coils of the rotational movement of the brushless electric motor, for example by not applying a rotating field. Therefore, in this case, it is also advantageously possible to apply any electric tone generation signal to the brushless electric motor without causing or impairing rotational movement.

It is a further development that the domestic appliance is set up to switch between at least two types of modulation (for example pulse density modulation, frequency modulation, pulse duration modulation and pulse pause or pulse width pause modulation, etc.). As a result, a particularly favorable (for example loud and / or clear) output of acoustic signals may be achieved.

In particular, it is a further development that the domestic appliance is set up to switch between at least two types of modulation depending on a pulse duration of the PWM drive signal not modulated with the tone generation signal. It is considered that possibly one or more types of modulation allow a favorable output of acoustic signals with a smaller change in the drive characteristics of the electric motor than other types of modulation.

It is also an embodiment that the household appliance is adapted to generate at least one tone generation signal or modulated drive signal for outputting acoustic signals in the form of speech. Because it has surprisingly been found that even complex language (words, etc.) can be reproduced intelligibly by the electric motor.

It is yet another embodiment that the household appliance is adapted to generate at least one tone generation signal or modulated drive signal for outputting acoustic signals in the form of tone frequency-varied tone sequences. In particular, it has surprisingly been found that even melodies can be recognized by the electric motor.

It is a development that the electric motor has a motor control or is connected to such. The motor control in turn may be connected to a central control device. The modulated drive signals may be generated by the controller and transmitted to the motor controller, with corresponding currents being passed through the coils of the motor by means of the motor controller. In another variant of the control device, for example, only the desired speed and / or the at least one tone generation signal (eg a desired tone sequence as an analog tone or as encoded data, eg "032", "Alarm 2" or "laundry ready") to Motor control transmitted and generated by the engine control the correspondingly modulated drive signal.

It is a more understandable, especially louder, reproduction of sounds (including melodies and / or speech) preferred embodiment that the electric motor is mechanically connected to a serving as a resonant body of the household appliance.

It is yet another embodiment that serving as a resonant body component is an inner housing of the household appliance, which housing limits a treatment room of the household appliance. So a particularly large sound or resonance body is used.

It is also an embodiment that the serving as a resonant body component is an outer housing of the household appliance. This allows a particularly attenuation-free sound radiation.

It is also a further embodiment that the household appliance is a cooking appliance. The treatment room may then in particular be a cooking space delimited by a cooking space wall. It is a special development that the cooking appliance has an oven (eg a stand-alone oven or a stove). Then, the inner housing may for example be a furnace muffle, which emits a particularly good sound box. It can cause a particularly wide bandwidth and strong amplitude of the acoustic signal. The use A cooking chamber wall, in particular a furnace muffle, may have the further advantage that it is made possible by the strong vibrations generated thereon by the electric motor, in particular in the audible range and / or in the ultrasonic range, for example by loosening adhering food particles from the walls due to the vibrations.

It is also an embodiment that the electric motor is a circulating air motor, in particular a cooking appliance such as a baking oven, a Dampfgargeräts, a microwave oven or a combination thereof. The circulating air motor may in particular serve to operate a fan or fan, for example to circulate air in the cooking chamber, e.g. during a convection or a hot air operation of a baking oven. However, the electric motor may also be another drive motor, e.g. to blow fresh air into the cooking chamber or to remove fumes from the cooking chamber as part of a steam blower.

However, the invention is not limited to cooking appliances and may be e.g. also affect refrigerators and laundry care appliances. Thus, the electric motor may be a drive motor of a laundry drum, a washing machine or a tumble dryer. Also, the electric motor may be a drive motor of a drive of a heat pump of a tumble dryer, in particular a drive motor of a compressor of a compressor heat pump.

The invention is also achieved by a method for operating at least one electric motor, in particular a brushless DC motor, of a domestic appliance, wherein the electric motor is supplied with electrical tone generation signals which cause an output of acoustic signals by the brushless DC motor. The method can be configured analogously to the household appliance and has the same advantages.

The above-described characteristics, features, and advantages of this invention, as well as the manner in which they will be achieved, will become clearer and more clearly understood in connection with the following schematic description of exemplary embodiments which will be described in detail in conjunction with the drawings. In this case, the same or equivalent elements may be provided with the same reference numerals for clarity.

1 shows a sectional side view of a household appliance with an electric motor in the form of a brushless DC motor;

2 shows a plot of a tone generation signal;

3 shows a plot of a drive signal of the brushless DC motor;

4 shows a plot of a drive signal modulated with the tone generation signal according to a first embodiment; and

5 FIG. 12 shows a plot of a tone generation signal together with the drive signal modulated by the tone generation signal according to a second embodiment. FIG.

1 shows a sectional view in side view of a household appliance in the form of an oven 1 with a circulating air motor in the form of a brushless DC motor 2 trained electric motor. The brushless DC motor 2 has a motor control 3 on, for example, includes a microcontroller and which is intended to provide a suitable energization of coils of the DC motor 2 to produce its drive. The engine control 3 is with a control device of the oven 1 connected, which here, for example, a central control device 4 is and among other things, serves the DC motor 2 adjust. The central control device likes this 4 For example, a desired speed to the engine control 3 transmit, which regulates the energization of the coils accordingly.

The engine control 3 is set up here to output a pulse width modulated drive signal for energizing the coils. The larger the associated pulse duration, the greater the force on a drive shaft 5 of the DC motor 2 and the higher is a rotational speed of the drive shaft 5 attached fan wheel 6 , The fan wheel 6 serves to air in a cooking chamber 7 of the oven 1 circulate and so in particular to allow a recirculation mode or a hot air operation. For hot air operation like the fan 6 eg from a ring radiator 8th be surrounded. fan 6 and ring radiator 8th like from a baffle 9 be covered permeable to air.

The DC motor 2 is mechanically fixed with a cooking space 7 limiting oven muffle 10 connected, by which also the drive shaft 5 leads. Vibrations or vibrations of the DC motor 2 settle on the oven muffle 10 which consequently serves as a sound box for the DC motor 2 serves.

The central control device 4 is also equipped to control the engine 3 to cause the original drive signal to be changed, in particular to modulate, that of the DC motor 2 for a server of the oven 1 outputs clear audible signals. These acoustic signals are on the muffle furnace 10 transferred and strengthened there. The DC motor 2 thus serves as a sound output unit.

The central control device 4 For example, for such a change of the original drive signal, an analog or a digitally present tone generation signal to the motor controller 3 transfer. The engine control 3 then modulates the original drive signal accordingly. The central control device 4 alternatively, only a corresponding command sequence to the motor control 3 send, eg "Alarm 2", and the engine control 3 modulates the original drive signal accordingly, for example, to output a specific acoustic alarm signal, or generates the modulated drive signal instead of the original drive signal.

2 1 shows as a solid line a tone generation signal TES as a plot of a dimensionless signal amplitude A over time t in arbitrary units. The signal amplitude A may represent a measure of an electrical voltage, for example. The tone generation signal TES here is a sinusoidal wave, which corresponds to an acoustic signal, for example.

3 shows an original pulse width modulated drive signal ATS of the brushless DC motor 2 as a plot of a dimensionless signal amplitude A2 over time t in arbitrary units. The signal amplitude A2 may represent, for example, a measure of an electrical current or an electrical voltage. The drive signal ATS is present as a sequence of pulses P with a constant pulse duration W and a constant period T or (pulse) frequency f = 1 / T. Both the pulse duration W and the pulse frequency f are by means of the motor control 3 variable, and thus a duty cycle W / T. The higher the duty cycle W / T, the higher the speed of the DC motor 2 , The pulse frequency f may be varied between 15 kHz and 30 kHz, for example. The only driven by an original pulse width modulated drive signal ATS DC motor 2 does not produce audible audible signals.

4 shows a plot of a with the tone generation signal TES pulse width modulated drive signal mATS according to a first embodiment. To generate the pulse duration modulated drive signal mATS the principle known method of pulse width modulation is applied, wherein the pulse duration W of the individual pulses P of the original drive signal ATS is changed depending on the then present amplitude of the tone generation signal TES, for example, above a predetermined amplitude threshold and below of the predetermined amplitude threshold is reduced. The amplitude threshold need not be at an amplitude value of zero. The amplitude threshold value may be set depending on a pulse duration W of the original drive signal ATS.

With output of the pulse width modulated drive signal mATS generates the DC motor 2 the audible acoustic signals based on the modulation. Namely, the pulse width modulated drive signal mATS is demodulated into a current waveform corresponding to the tone generation signal TES by the inductive response of its coils. As the current generates the magnetic field, a mechanical vibration is generated at the DC motor 2 generated, which is audible as a sound wave. The frequency width of the acoustic signals may in particular be in the range of a few kHz, for example up to 5 kHz, in particular up to 1 kHz.

5 shows as a solid line the tone generation signal TES as a plot of the dimensionless signal amplitude A over time t in arbitrary units. 5 also shows an associated delta or pulse density modulated drive signal mATS2 as a plot of the dimensionless signal amplitude A2 over time t. To generate the pulse-density-modulated drive signal mATS2 the principle known method of pulse density modulation is applied, in which case the pulse duration W of the individual pulses P of the original drive signal ATS is changed depending on the then present amplitude of the tone generation signal TES, eg above a predetermined amplitude threshold increases and is exposed below the predetermined amplitude threshold. The amplitude threshold need not be at an amplitude value of zero. The amplitude threshold value may be set depending on a pulse duration W of the original drive signal ATS. With output of the pulse width modulated drive signal mATS2 generates the DC motor 2 the audible acoustic signals based on the modulation.

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

Thus, the original drive signal may also be pulse-pulse-modulatable and / or frequency-modulatable for the purpose of outputting acoustic signals.

However, any other suitable electric motor may be used instead of a brushless DC motor, e.g. by means of a brush DC motor or an AC motor, in particular a brushless AC motor,

Generally, "on", "an", etc. may be taken to mean a singular or a plurality, in particular in the sense of "at least one" or "one or more" etc., unless this is explicitly excluded, e.g. by the expression "exactly one", etc.

Also, a number may include exactly the specified number as well as a usual tolerance range, as long as this is not explicitly excluded.

LIST OF REFERENCE NUMBERS

1

 oven

2

 brushless DC motor

3

 motor control

4

 central control device

5

 drive shaft

6

 fan

7

 oven

8th

 heaters circular

9

 baffle wall

10

 muffle furnace

A

 dimensionless signal amplitude

A2

 signal amplitude

ATS

 pulse width modulated drive signal

mATS

 Pulse-duration modulated drive signal

mATS2

 pulse density modulated drive signal

P

 Pulse

t

 Time

T

 period

TES

 Tone generation signal

W

 pulse duration

W / T

 duty cycle

Claims (15)

Household appliance ( 1 ), comprising - at least one electric motor ( 2 ) which is drivable by means of an electrical drive signal (ATS, mATS, mATS2), and - at least one sound output unit which generates at least one acoustic signal based on at least one electrical tone generation signal (TES), characterized in that at least one electric motor ( 2 ) also serves as a sound output unit in that the drive signal (ATS) can be modulated by means of the at least one tone generation signal (TES). Household appliance ( 1 ) according to claim 1, characterized in that the electric motor is a brushless electric motor, in particular a brushless DC motor ( 2 ) is. Household appliance ( 1 ) according to one of the preceding claims, characterized in that the drive signal (ATS) of the electric motor ( 2 ) is a pulse width modulated signal. Household appliance ( 1 ) according to claim 3, characterized in that the drive signal (ATS) by means of the at least one tone generation signal (TES) is pulse width modulated. Household appliance ( 1 ) according to one of claims 3 or 4, characterized in that the drive signal (ATS) by means of the at least one tone generation signal (TES) is pulse density modulated. Household appliance ( 1 ) according to one of claims 3 to 5, characterized in that the drive signal (ATS) by means of the at least one tone generation signal (TES) is Pulse pause modulated. Household appliance ( 1 ) according to one of claims 3 to 6, characterized in that the drive signal (ATS) by means of the at least one tone generation signal (TES) is frequency modulated. Household appliance ( 1 ) according to one of the preceding claims, characterized in that the domestic appliance ( 1 ) is adapted to generate at least one electrical tone generation signal (TES) for outputting at least one acoustic signal in the form of speech. Household appliance ( 1 ) according to one of the preceding claims, characterized in that the domestic appliance ( 1 ) is adapted to generate at least one electrical tone generation signal (TES) for outputting at least one acoustic signal in the form of tone-frequency-varied tone sequences, in particular melodies. Household appliance ( 1 ) according to one of the preceding claims, characterized in that the electric motor ( 2 ) with a resonant body component ( 10 ) of the household appliance ( 1 ) is mechanically connected. Household appliance ( 1 ) according to one of the preceding claims, characterized in that the component serving as a resonant body comprises an inner housing ( 10 ) of the household appliance ( 1 ), which housing is a treatment room ( 7 ) of the household appliance ( 10 ) limited. Household appliance ( 1 ) according to one of the preceding claims, characterized in that the component serving as a resonant body comprises an outer housing of the domestic appliance ( 1 ). Household appliance ( 1 ) according to one of the preceding claims, characterized in that the household appliance is a furnace, in particular oven ( 1 ) is. Household appliance ( 1 ) according to claim 13, characterized in that the electric motor ( 2 ) is a circulating air motor. Method for operating at least one electric motor ( 2 ) of a household appliance ( 1 ), characterized in that at least one drive signal (ATS) of the electric motor, in particular brushless DC motor ( 2 ) is modulated by means of at least one electrical tone generation signal (TES) such that an output of at least one acoustic signal by the electric motor ( 2 ) is effected.

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