JP2001079285A - Washing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect vibrations of a washing tub by a simple structure and at a low cost and to reduce noise at the dehydration based on the detection of vibrations. SOLUTION: This washing machine consists of an outer tub 2, magnets 8 and 22 mounted at the top and the bottom of the outer tub, a water-level sensor 10 and a coil 23 adjacent to the magnets respectively, a rotation sensor 20, and a control part 14 receiving output signals from the water-level sensor 10, the coil 23 and the rotation sensor 20 and detecting vibrations of the upper/lower parts of the outer tub and the quantity of fabrics based on the output signals to control the washing motion of the washing machine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a washing machine, and more particularly to a method for detecting vibration of an outer tub and a method for controlling rotation of an inner tub.

[0002]

2. Description of the Related Art The following three examples are given as conventional examples of a washing machine which detects a vibration of an outer tub and controls a washing operation based on the detected vibration.

As a first example, there is a fully automatic washing machine described in JP-A-8-243295. In this method, vibration detecting means are provided on the upper and lower parts of the outer tank supported by the suspension, and means for changing the center of gravity of the outer tank are provided. By comparing the magnitude of the vertical vibration, the position of the center of gravity of the outer tub is changed so that the support point of the outer tub approaches a portion where the vibration is small.

[0004] As a second example, there is a washing machine combined with dehydration described in JP-A-9-294892. In this method, a water level detecting means for changing the insertion amount of the iron core into the coil according to the water level in the outer tub is attached to the upper part of the outer tub, and the iron core vibrates due to the vibration of the outer tub, and the insertion amount fluctuates. Configuration. The water level detection means detects the water level and the vibration of the outer tub, and controls the washing operation such as the rotation control of the inner tub during dehydration based on the detection results.

[0005] As a third example, there is a washing machine described in JP-A-9-94380. This is to detect the water level in the outer tank and the vibration of the outer tank by one water level sensor. Specifically, 2 inserted into the coil of the water level sensor
A plurality of magnetic bodies are provided. The first magnetic body has a structure in which the insertion amount changes in accordance with the water level in the outer tub, and the second magnetic body has a structure in which the insertion amount changes in accordance with the vibration of the upper end portion of the suspension supporting the outer tub.

[0006]

The first prior art has a structure in which the position of the center of gravity is changed by moving the outer tub up and down, so that a vertical mechanism for the entire outer tub is required. Since there are usually four suspensions, four mechanisms are also required. Since the entire outer tank weighs several tens of kilograms even after draining, the mechanism is
kg lifting power is required. In addition to this, two vibration detecting means are required, and the cost for these components is required.

In the second conventional example, a vibration component in the insertion direction of the iron core, that is, a vertical direction of the coil can be detected, but a vibration component in a direction perpendicular to this direction cannot be detected. Accordingly, there is a problem that even if the vertical vibration of the outer tub can be detected, the front-back, left-right vibration cannot be detected. Also, since the vibration of only the upper portion of the outer tank is detected, the vibration state of the entire outer tank cannot be correctly detected.

[0008] A third conventional example is an upper end of a suspension,
In other words, the configuration is such that the vibration of the mounting portion to the outer frame is detected, but the vibration is not necessarily proportional to the vibration of the outer tub itself. Therefore, the vibration state of the entire outer tank cannot be correctly detected.

An object of the present invention is to provide a washing machine which detects the vibration state of the entire outer tub with a simple structure and at low cost, and performs control for reducing noise during dehydration based on the detected information. It is in.

[0010]

In order to achieve the above object, a washing machine according to the present invention is characterized in that a laundry amount signal output by the laundry amount detecting means and an inner tub output by the rotational speed detecting means. The rotation speed of the inner tub is controlled by the control means based on the rotation speed signal, the upper vibration signal output from the first vibration detecting means, and the lower vibration signal output from the second vibration detecting means. Control.

Specifically, the washing machine according to the present invention is provided with vibration detecting means above and below the outer tub. The upper vibration detecting means includes a magnet provided on the outer tank and a water level detecting means having a coil provided near the magnet.
That is, the vibration is detected from the induced voltage generated in the coil due to the vibration of the magnet. Then, a control means for controlling a series of washing operations such as washing, rinsing and dehydration acquires an output signal of the vibration detecting means and detects vibration of the outer tub based on the output signal.

When the outer tub vibrates during dehydration, the control means detects the vibration of the upper and lower parts of the outer tub by the vibration detecting means. At the time of dehydration, when the amount of cloth is large, the correlation between the vibration and noise at the upper part of the outer tub is high, and when the amount of cloth is small, the correlation between vibration and noise at the lower part of the outer tub is high. Therefore, at the start of washing or at the start of dehydration, the control means determines the amount of cloth by the cloth amount detecting means, based on the vibration of the upper part of the outer tub when the amount of cloth is large, and when the amount of cloth is small, The rotation of the inner tank is controlled based on the vibration of the lower part. A specific control method is to set an upper limit value for the rotation speed of the inner tub according to the magnitude of the vibration, monitor the rotation speed of the inner tub by the rotation speed detecting means, and determine the rotation speed. Control to keep the value below the upper limit is performed. Therefore, according to the present invention, the noise can be suppressed to a certain level or less without excessively deteriorating the dewatering effect, and excessive noise during dewatering can be prevented.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A washing machine according to one embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a washing machine according to one embodiment of the present invention. The inner tub 1 is a rotatable tub that stores laundry and has a number of dehydration holes on the side.
The outer tank 2 is a tank that encloses the inner tank 1. The rotating blade 3 is a rotatable stirring blade provided at the center of the bottom of the inner tank 1,
Stir the laundry when washing and rinsing. The rotating mechanism 4 is provided below the outer tub 2 and is a mechanism for rotating the inner tub 1 and the rotary wings 3, and includes a motor, a gear, and an electromagnetic clutch. The suspension rod 5 is a metal rod that suspends the outer tub 2, and supports a lower portion of the outer tub 2 with vibration isolation.

The rotating shaft 6 is a shaft for rotating the inner tub 1 or the rotating blades 3 and is connected to the rotating mechanism 4. Rotation mechanism 4
Selects one of the inner tub 1 and the rotary wing 3 and rotates it by an electromagnetic clutch. The outer frame 7 is a plate surrounding the side surface of the washing machine, and has a substantially rectangular parallelepiped shape. It supports the hanging bar 5 at the upper four corners. The first magnet 8 is a magnet attached to the upper part of the outer tub 2, and is located immediately below the water level sensor 10. The air chamber 21 is provided at a lower portion outside the outer tub 2, and the lower portion communicates with the outer tub 2. The air pipe 9 is a vinyl pipe or the like that connects the upper part of the air chamber 21 and the water level sensor 10.
As the water level in the outer tub 2 rises, the air in the air chamber 21 is pushed up, and the air pressure rises.

The water level sensor 10 is a mechanism for outputting an electric quantity indicating the water level of the outer tub 1, and the electric quantity corresponds to the air pressure. The changeover switch 11 is connected to the water level sensor 10.
Is a switch for selecting and connecting the output terminal of (1) to the first amplification and rectification circuit 12 or to the oscillation circuit 13. The switching is performed by the control unit 14. The first amplification and rectification circuit 12 is a circuit that amplifies, rectifies and smoothes the output signal of the water level sensor 10 and outputs the signal as a DC signal. The oscillating circuit 13 is a circuit that is connected to the water level sensor 10 to generate an AC signal, and the frequency of the AC depends on the electric quantity.

The control unit 14 is a circuit for acquiring a signal, performing an operation, outputting a control signal, and controlling a washing operation in accordance with a program recorded therein, and is a commercially available one-chip microcomputer or the like. It has an input / output terminal for digital signals, an input terminal for analog signals, and an A / D (analog-to-analog) for converting the analog signals into digital signals.
Digital) converter. The control unit 14 obtains the output signals of the first amplification and rectification circuit 12 and the second amplification and rectification circuit 24 from the input terminal of the analog signal, and outputs the output signal of the oscillation circuit 13 to the digital signal. Obtain from input terminal.

The drive circuit 15 is a circuit for generating electric power for driving the rotating mechanism 4 and electric power for opening and closing the water supply valve 17 and the drain valve 19 based on a control signal from the control unit 14. The water supply pipe 16 is a water supply pipe that is connected to a water supply or the like and supplies water to the inner tank 1 and the outer tank 2. The drain pipe 18 is a water pipe connected to the bottom of the outer tank 2 to drain water in the outer tank 2. The water supply valve 17 and the drainage valve 19 are respectively connected to the water supply pipe 16.
Alternatively, it is an opening / closing valve provided in the middle of the drain pipe 18, and both perform opening / closing operation by electric power from the drive circuit 15.

The rotation sensor 20 includes the inner tank 1 or the rotary blade 3
Is a sensor for measuring the number of rotations of the rotating mechanism 4, and is composed of, for example, a magnet attached to a rotating part of the rotating mechanism 4 and a coil attached to a fixed part. The control unit 14 obtains the induced voltage generated in the coil, and calculates the rotation speed from the obtained voltage. The second magnet 22 is a magnet attached to a lower portion of the outer tub 2, and the coil 23 is a coil provided on the outer frame 7 near the second magnet 22. The second amplifying and rectifying circuit 24 is a circuit similar to the first amplifying and rectifying circuit 12, and amplifies, rectifies, and smoothes the voltage generated in the coil 23.

FIG. 2 is a sectional view showing an example of the structure of the water level sensor 10. The magnetic body 102 is inserted inside the coil 101. One end of the coil 101 is a changeover switch 11
And the other end is commonly grounded. The magnetic body 102
It is a bar-shaped magnetic material that stands upright at the center of the film surface 103, and is supported from above by a spring 105. The film surface 103 is a flat thin film that partitions the inside of the air chamber 104 up and down, and is movable up and down. The lower part of the air chamber 104 is connected to the air pipe 9. When the water level in the outer tub 2 rises, the air pressure in the air pipe 9 rises, and the membrane surface 103 rises.

Thus, the coil 101 of the magnetic body 102
The amount of insertion into the device increases. Since the inductance of the coil 101 changes according to the insertion amount, as a result, it changes according to the water level of the outer tub 2. Therefore, the coil 101 is connected to the oscillation circuit 1
3, the oscillation frequency of the circuit changes according to the inductance, and consequently, changes according to the water level.

FIG. 3 is a block diagram showing the configuration of the first amplifying and rectifying circuit 12. As shown in FIG. The amplifier circuit 12a is a circuit that amplifies an AC signal. The integration circuit 12b is a circuit that outputs a signal obtained by substantially integrating the input signal. The rectification and smoothing circuit 12c is a circuit that converts an AC signal into a DC signal that is proportional to its effective value. The second amplification and rectification circuit 24 has the same configuration.

Hereinafter, the vibration of the outer tank 2 causes the coil 10
1 and a method of detecting the vibration of the outer tub 2 based on the induced voltage generated in the coil 23 will be described. The detection of the vibration in the present embodiment is the measurement of the vibration amplitude.
The vibration amplitude may be simply referred to as amplitude. Control unit 14
Connects the water level sensor 10 to the first amplifying and rectifying circuit 12 with the changeover switch 11 on the a side. Since the first magnet 8 or the second magnet 22 is provided near the water level sensor 10 or the coil 23, respectively, these magnets vibrate when the outer tub 2 vibrates, and are guided to the coil 101 or the coil 23. Voltage is generated.

The induced voltage generated in the coil is proportional to the temporal change rate of the magnetic flux density inside the coil. When the magnet vibrates, the relative distance between the magnet and the coil changes, so that the magnetic flux density also changes, and an induced voltage is generated in the coil. Since the fluctuation width of the relative distance increases as the vibration amplitude increases, the fluctuation width of the magnetic flux density also increases, and the induced voltage increases.
Generally, the vibration of the outer tub 2 during dehydration is a combination of vibration components in the front-back, left-right, and up-down directions, but the relative distance fluctuates in any case of the vibration direction, so that an induced voltage is generated. Therefore, the induced voltage has a value corresponding to the vibration amplitude regardless of the vibration direction of the upper part or the lower part of the outer tank 2. Since the induced voltage is proportional to the temporal change rate of the magnetic flux density, it has a differential characteristic that increases in proportion to the vibration frequency when the vibration amplitude of the magnet is the same. Therefore, the higher the rotation speed of the inner tank 1,
Since the vibration frequency of the outer tub 2 increases, the induced voltage also increases.

Therefore, regardless of the rotation speed of the inner tank 1, the outer tank 2
In order to obtain a voltage proportional to the oscillation amplitude of
The differential characteristics are corrected using 2b and 24b. The integration circuits 12b and 24b are circuits having an integration characteristic in which the amplification factor of the circuit = output voltage / input voltage is substantially inversely proportional to the frequency of the input signal in a certain frequency band or more.
Therefore, when the induced voltage is applied to the integrating circuit, the differential characteristic of the induced voltage is canceled by the integrating characteristic of the integrating circuit, and the output voltage of the integrating circuit becomes outside regardless of the rotation speed of the inner tank 1. It is almost proportional to the vibration amplitude of the tank 2.

FIGS. 4 and 5 show the outer tub 2 during dehydration.
5 is an example of a temporal change of a displacement obtained by amplifying, rectifying, and smoothing a displacement of an upper portion of the coil and an induced voltage of the coil 101 by the first amplifying and rectifying circuit 12. FIG. 4 shows a case where the first amplifying and rectifying circuit 12 does not include the integrating circuit 12b.
Shows the case where the same circuit exists. 0 seconds at the start of dehydration,
After 120 seconds, the power supply to the motor of the rotation mechanism 4 is cut off.
As described above, the induced voltage of the coil 101 increases as the rotation speed of the inner tank 1 increases.

In FIG. 4, since the rotation speed is low immediately after the start of dehydration, a large amplitude due to resonance of the outer tub 2 does not appear in the voltage, and the voltage increases as the rotation speed increases. If the differential characteristic is corrected by the integration circuit 12b, a large amplitude immediately after the start of dehydration appears in the voltage, as shown in FIG.

Also, except for the first about 10 seconds, the amplitude and the voltage are approximately proportional. Therefore, if the integration circuit 12b is used, the differential characteristic of the electromagnetic induction can be corrected and a voltage substantially proportional to the amplitude can be obtained, so that the amplitude can be easily calculated from the voltage. As shown in FIG. 4, the rotation speed of the inner tub 1 during dehydration increases for several tens of seconds after the start of dehydration, and thereafter becomes substantially constant.

Hereinafter, a period in which the increase in the number of revolutions is completed and is kept substantially constant may be referred to as a dehydration steady state. Further, the voltage generated by the coil 101 is converted to a first amplification and rectification circuit 12.
The voltage amplified, integrated, rectified, and smoothed by the upper coil voltage, and the voltage generated by the coil 23 amplified, integrated, rectified, and smoothed by the second amplification and rectification circuit 24 is the lower coil voltage. Sometimes referred to as voltage.

FIG. 6 shows the relationship between the maximum amplitude (maximum value of displacement-minimum value) of the upper part of the outer tub 2 and the average value of the upper coil voltage and the maximum value of the lower part of the outer tub 2 in the dehydration steady state in a plurality of dehydration experiments. This is the relationship between the amplitude and the average value of the lower coil voltage. At the time of steady dehydration, there is a high correlation between the amplitude and the coil voltage both above and below the outer tub 2, and therefore the amplitude can be easily calculated from the voltage.

FIG. 7 shows the noise during dehydration.
This will be described with reference to FIGS.

FIG. 7 shows an example of a temporal change in the noise level, the upper coil voltage, and the rotation speed of the inner tub 1 during dehydration.
The dehydration start time is set to 0, and the current of the motor is cut off at time T0. After time T, the number of revolutions is substantially constant, and from time T to T0 is the dehydration steady state. The noise level increases with the number of rotations, and reaches a maximum at the time of steady dehydration.

FIGS. 8 to 11 show the average value of the noise level and the average value of the upper and lower coil voltages when the JIS test cloth is washed many times in a washing machine with a rated capacity of 7 kg during dehydration. It is an example of the relationship with. FIG. 8 shows the relationship between the noise level and the upper coil voltage when the amount of cloth is 5 kg, FIG. 9 shows the relationship between the noise level and the lower coil voltage when the amount of cloth is the same, FIG.
0 shows the relationship between the noise level and the upper coil voltage at the cloth weight of 1.5 kg, and FIG. 11 shows the relationship between the noise level and the lower coil voltage at the same cloth weight. The cross-correlation coefficients between the noise level and the upper or lower coil voltage are 0.91, 0.86, 0.71 and 0.85 in the order of FIGS.

When the amount of cloth is large, both the upper and lower coil voltages have a high correlation with the noise level, and particularly have a high correlation with the upper coil voltage. When the amount of cloth is small, the lower coil voltage has a high correlation with the noise level, but the upper coil voltage has a relatively low correlation with the noise level. Therefore, when the cloth amount is large, the noise level can be estimated from the upper coil voltage, and when the cloth amount is small, the noise level can be estimated from the lower coil voltage.

FIG. 12 shows an example of the relationship between the number of revolutions of the inner tank 1 and the noise level, in the case of a 5 kg JIS test cloth.
The rotation speed of the inner tub 1 at the time of steady dehydration is 800 rpm or more. In this rotation speed range, every time the rotation speed is reduced by 100 rpm, the noise level is reduced by about 3 dB.

FIG. 13 shows the amount of cloth and the first magnet 8-coil 1
01, the amount of cloth and the second magnet 22-coil 23
It is an example of the relationship with the distance between. As the amount of cloth, both the dry weight and the weight of the compress at the time of steady dehydration are shown. Since the outer tub 2 is supported by the hanging rod 5 having a spring, the larger the cloth amount, the greater the deformation of the spring and the outer tub 2
Sinks. Therefore, the distance between the first magnet 8 and the coil 101 increases with the amount of cloth. Further, as the outer tank 2 sinks, the position of the second magnet 22 fixed to the outer tank 2 also decreases. On the other hand, the position of the second coil 23 fixed to the outer frame 7 remains unchanged regardless of the amount of cloth. Accordingly, the positional relationship between the two changes in accordance with the cloth amount, and the relation between the cloth amount and the distance between the magnet and the coil is as shown in FIG.

FIG. 14 shows an example of the relationship between the cloth amount and the upper coil voltage and the relationship between the cloth amount and the lower coil voltage when the vibration amplitude of the outer tub 2 is constant. Since the distance between the magnet and the coil changes according to the amount of cloth, the voltage also changes according to the amount of cloth. Therefore, in order to detect the upper and lower amplitudes of the outer tub 2 from the voltage, it is necessary to detect the cloth amount and refer to this.

Next, a method of detecting the amount of cloth during dehydration will be described with reference to FIG. This is a method of determining the amount of cloth based on the time from the start of dehydration to the time when the rotation speed of the inner tub 1 reaches a certain value (for example, 150 rpm). If the rotation force of the rotation mechanism 4 is the same, the greater the mass of the cloth in the inner tank 1, the slower the increase in the number of rotations and the longer the time. FIG. 15 is an example of the distribution of time from the start of dehydration to the rotation speed reaching 150 rpm for six types of cloth amounts. The distribution of the time in each cloth amount hardly overlaps, and the cloth amount can be determined in six stages from the time.

Hereinafter, a method of controlling the rotation of the inner tub 1 to suppress the noise level to a certain level or less during dehydration will be described with reference to FIGS. 8 to 11 and FIGS.

First, a description will be given with reference to FIGS. As shown in each figure, the relationship between the noise level and the upper and lower coil voltages at the time of steady dehydration is obtained experimentally in advance for several types of cloth. Then, the relationship between the noise level and the upper and lower coil voltages at each cloth amount is approximated by an approximate straight line. The value at which the noise level during dehydration is desired to be suppressed below this is set as the upper limit threshold value of the noise level. For example, the threshold value L1 is set to 54 dB. Then, the upper and lower coil voltages corresponding to L1 are obtained on the approximate straight line, and these are set as thresholds V1 or V2 of the upper and lower coil voltages.
For example, when the cloth weight is 5 kg, the threshold values of the upper and lower coil voltages are V1 (5) and V2 (5), respectively.

Next, a method of controlling the rotation of the inner tub 1 during dehydration will be described with reference to FIG. At the start of dehydration, t = 0. First, the control unit 14 determines a cloth amount.
For example, as described above, the determination is made based on the time when the rotation speed r of the inner tank 1 reaches 150 rpm. The control unit 14 acquires the upper and lower coil voltages Vu and Vd, compares them with the threshold value V1 or V2, and sets the upper limit rotational speed r1 of the inner tank 1 based on the result. However, at the time of low-speed rotation immediately after the start of dehydration, the outer tub has a large amplitude due to a resonance phenomenon.
d is a large value.

For this reason, after the rotation speed of the inner tub 1 exceeds a certain value, the control unit 14 makes the comparison. V when the amount of cloth is large
u and V1, and if Vu> V1, ΔVu = Vu−
R1 is set according to V1. Vd when the amount of cloth is small
And V2, and if Vd> V2, ΔVd = Vd−V
R1 is set according to 2. FIG. 17 shows an example when the amount of cloth is large. If Vu ≦ V1, r1 = maximum rotational speed rma
x (for example, 1000 rpm). The maximum rotation speed is the highest rotation speed that can be obtained when the rotation mechanism 4 rotates the inner tank 1. If Vu> V1, r1 is reduced according to ΔVu. In the example of the figure, r1 and ΔVu have a linear relationship, and r1
= Rmax−c1 · ΔVu. The coefficient c1 is determined from an approximate expression of the relation between the noise level and the upper coil voltage and a relational expression between the noise level and the rotation speed.

For example, in FIG. 12, the approximate expression of the relationship between the rotational speed r and the noise level L is L (dB) = 0.03r (rpm) +
Assuming 24.6, the rotation speed change Δr = (1 / 0.03) Δ
L. In addition, the approximate straight line in FIG.
If L (dB) −5.85, ΔL = (1 / 0.12)
3) It becomes ΔVu. From the above, c1 = (Δr / ΔL) (Δ
L / ΔVu) = (1 / 0.03) (1 / 0.123) = 2
71. Similarly, when the cloth amount is small, r1 = rmax
−c2 · ΔVd, c2 = (Δr / ΔL) (ΔL / ΔVd).

Returning to FIG. When V exceeds V1 at t = t1, the control unit 14 determines that r1 =
rmax. When t> t1, r1 and ΔV described above are used.
r1 is determined according to the relational expression between u or r1 and ΔVd. After r reaches r1, the control unit 14 sets the rotational speed r to r
The rotation of the inner tank 1 is controlled so as to keep it at around 1.

A specific example of the above-described rotation control of the inner tub 1 during dehydration will be described with reference to the flowchart of FIG. At the start of dehydration, the control unit 14 starts energizing the motor of the rotation mechanism 4. The initial value of the rotation speed upper limit r1 is the maximum rotation speed rmax. Then, the rotation speed of the inner tank 1 is obtained, and this is 150 rpm.
(S-1).
Then, the control unit 14 selects a calculation formula for calculating the upper limit rotational speed r1 from the upper and lower coil voltage thresholds V1 and V2 and the upper and lower coil voltages according to the cloth amount. The voltage threshold and the calculation formula are obtained from the relationship between the noise level during dehydration and the upper and lower coil voltages as shown in FIGS. The relationship differs depending on the amount of cloth.

Therefore, the relationship is experimentally determined in advance for several types of cloth amounts to be used as the determination value of the cloth amount, and the voltage threshold value and the calculation formula are obtained from this (s-
2). Thereafter, until the dehydration is stopped, the control unit 14 acquires the upper and lower coil voltages Vu and Vd at regular intervals (s-3). Then, the control unit 14 waits for the rotation speed r of the inner tank 1 to reach a constant value ra (for example, 500 rpm). This is to avoid a period in which the outer tub has a large amplitude due to a resonance phenomenon immediately after the start of dehydration (s-4).

The controller 14 sets a large amount of cloth if the determined amount of cloth exceeds a certain threshold value (eg, 1/2 of the rated capacity of the washing machine), and sets a small amount of cloth if it does not exceed the threshold (s-5). In the case of a large amount of cloth, the control unit 14 first compares the upper coil voltage Vu with the threshold value V1 (s-6). If the amplitude of the upper part of the outer tub 2 is large and Vu> V1, the upper limit rotation is performed from the difference ΔVu. Calculate the number r1.

For example, when the cloth weight is 5 kg, r1 is calculated from ΔVu = Vu−V1 (5) based on the relationship between the noise L and Vu in FIG. 8 (s−7). The amplitude is small and Vu is V1
Even in the following case (s-6), if the amplitude of the lower part of the outer tub 2 is large, the noise level during dehydration becomes high.
4 compares the lower coil voltage Vd with the threshold value V2 (s-
8) If Vd> V2, the upper limit rotational speed r1 is obtained from the difference ΔVd.
Is calculated.

For example, when the cloth amount is 5 kg, L and Vd in FIG.
From the relation ΔVd = Vd−V2 (5), r1
Is calculated (s-9). When Vd is V2 or less, (s−
8), r1 = rmax is set (s-11). In the case of a small amount of cloth (s-5), the control unit 14 compares the lower coil voltage Vd with the threshold value V2 (s-8), and if Vd> V2, the difference ΔVd
From the upper limit rotational speed r1.

For example, when the cloth weight is 1.5 kg, L in FIG.
ΔVd = Vd−V2 (1.5) based on the relationship between Vd and Vd.
Then, r1 is calculated from (s-9). When Vd is equal to or lower than V2 (s-8), r1 = rmax is set (s-11).

Then, the control unit 14 sets the rotation speed r of the inner tank 1 to r.
If r exceeds r1, control is performed to reduce r. Specifically, if r exceeds r1 by a fixed value Δr1 or more (s-11), the applied voltage E of the motor is increased by a fixed value Δ
The frequency F of the voltage is decreased by a constant value ΔF by E (s-12). If r is equal to or less than r1, control to increase r is performed. Specifically, if r is lower than r1 by a fixed value Δr1 or more (s-13), E is increased by ΔE and F is increased by ΔF (s-14).

With the above control, it is possible to keep r near r1 after increasing r to r1. The controller 14 repeats the operations from (s-5) to (s-15) until the dehydration time ends or a dehydration error such as the user opening the lid during dehydration occurs (s-15). .

According to the present embodiment, the dehydration noise and the amplitude at the upper part of the outer tub 2 are highly correlated when the amount of cloth is large, and the noise and the amplitude at the lower part of the outer tank 2 are small when the amount of cloth is small. Is highly correlated, the amount of the cloth is determined at the time of dehydration.
The upper limit rotation speed is set based on the upper amplitude, and in the case of a small amount of cloth, the upper limit rotation speed is set based on the amplitude of the lower portion of the outer tub 2. Then, since the rotation speed of the inner tub 1 is controlled to be equal to or lower than the upper limit rotation speed, the noise level at the time of dehydration is suppressed to a certain level or less and the rotation speed is reduced more than necessary for any amount of cloth. There is no loss of effectiveness.

In the above embodiment, an example was described in which a magnet provided in the outer tank 2 and a coil provided near the magnet of the outer frame 7 were used as the vibration detecting means on the upper and lower parts of the outer tank 2. However, other vibration detecting means, such as a piezoelectric element,
Even if an acceleration sensor such as a gyro is used, the vibration of the outer tub 2 can be similarly detected, and the rotation of the inner tub 1 can be controlled based on the detection result so as to suppress noise during dehydration.

[0055]

As described above, according to the present invention, vibration detecting means is provided above and below the outer tub to detect the vibration of the entire outer tub. All can be detected.

At the time of dehydration, when the amount of cloth is large, the noise level has a high correlation with the vibration of the upper portion of the outer tub. When the amount of cloth is small, the noise level has a high correlation with the vibration of the lower portion of the outer tub. . Based on this, the cloth amount is detected by the cloth amount detecting means, and either the upper or lower vibration is selected according to the cloth amount, and the upper limit value of the rotation speed of the inner tank is set according to the vibration. However, since the control is performed to keep the rotation speed of the inner tub near the upper limit, the noise level during dehydration can be suppressed to a certain level or less without unnecessarily impairing the dehydration effect.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a washing machine according to an embodiment of the present invention.

FIG. 2 is a sectional view showing an example of the structure of the water level sensor of FIG.

FIG. 3 is a block diagram illustrating a configuration of a first amplification and rectification circuit of FIG. 1;

FIG. 4 is a characteristic diagram showing an example of a temporal change in amplitude of an upper portion of an outer tank and output voltages of an amplification and rectification circuit.

FIG. 5 is a characteristic diagram showing an example of a temporal change in amplitude of an upper portion of an outer tank and output voltages of an amplification and rectification circuit.

FIG. 6 is a characteristic diagram showing a relationship between amplitudes of upper and lower outer tubs and coil voltages.

FIG. 7 is a characteristic diagram showing an example of an amplitude of an outer tub and a temporal change of a coil voltage during dehydration.

FIG. 8 is a correlation diagram between the noise level during dehydration and the upper coil voltage when the cloth weight is 5 kg.

FIG. 9 is a correlation diagram between the noise level during dehydration and the lower coil voltage when the cloth weight is 5 kg.

FIG. 10 is a correlation diagram between the noise level during dehydration and the upper coil voltage when the cloth weight is 1.5 kg.

FIG. 11 is a correlation diagram between a noise level during dehydration and a lower coil voltage when the cloth weight is 1.5 kg.

FIG. 12 is a characteristic diagram illustrating an example of a method of controlling rotation of an inner tank during dehydration.

FIG. 13 is a characteristic diagram showing a relationship between the weight of laundry and a distance between a magnet and a coil.

FIG. 14 is a characteristic diagram showing a relationship between the weight of laundry and a coil generation voltage.

FIG. 15 is a characteristic diagram illustrating an example of a time required for the rotation speed of the inner tank to reach 150 rpm.

FIG. 16 is a characteristic diagram showing an example of a method of controlling rotation of an inner tub during dehydration.

FIG. 17 is a characteristic diagram illustrating an example of an upper limit rotation speed of an inner tub during dehydration.

FIG. 18 is a flowchart showing the operation of the control unit during dehydration.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Inner tank, 2 ... Outer tank, 3 ... Rotating blade, 4 ... Rotating mechanism, 5 ...
Hanging rod, 6: rotating shaft, 7: outer frame, 8: first magnet, 9: air tube, 10: water level sensor, 11: changeover switch, 12 ...
1st amplification and rectification circuit, 13 oscillation circuit, 14 control unit, 15 drive circuit, 16 water supply pipe, 17 water supply valve, 1
8 ... drain pipe, 19 ... drain valve, 20 ... rotation sensor, 21 ...
Air chamber, 22 ... second magnet, 23 ... coil, 24 ... second
Amplifying and rectifying circuit, 101 ... coil, 102 ... magnetic material,
103: membrane surface, 104: air chamber, 105: spring.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toshifumi Koike 502 Kandachi-cho, Tsuchiura-shi, Ibaraki F-term in Machinery Research Laboratory, Hitachi, Ltd. (Reference) 3B155 AA06 BA03 BB05 KA02 KA34 KA35 KA35 LA02 LA11 LB17

Claims (1)

[Claims] An outer frame, an outer tank supported by the outer frame for vibration isolation,
A rotatable inner tank that is encased in the outer tank, a rotating blade provided at the bottom of the inner tank, a rotating means for rotating the inner tank and the rotating blades, and detecting a rotation speed of the rotating means, Rotation number detection means for outputting a rotation number signal indicating the rotation number; first vibration detection means for detecting vibration of the upper part of the outer tub and outputting an upper vibration signal indicating the vibration; A second vibration detection unit that detects a lower vibration and outputs a lower vibration signal indicating the vibration; a cloth amount detection unit that detects a cloth amount in the inner tank and outputs information of the cloth amount; The information of the rotation speed signal, the upper vibration signal, the lower vibration signal, and the cloth amount is acquired, and the rotation speed signal, the upper vibration signal, the lower vibration signal, and the cloth amount information are obtained. Control means for controlling rotation of the rotation means, wherein the control means controls the upper vibration signal when the cloth amount is equal to or more than a predetermined value. Based on, if the fabric weight is less than the predetermined value, washing machine on the basis of the lower vibration signal, and wherein the controlling the rotation of said rotating means.