JP2000296289A - Washing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noise during the dewatering process by detecting vibration of washing tanks by a simple and low cost constitution. SOLUTION: A washing machine comprises a tub 2, magnets 8, 22 installed at upper and lower side of the tub 2, a water-level sensor 10 and a coil 23 mounted near the magnets, and a control means 14 which controls washing operation by obtaining output signals from the water-level sensor 10 and the coil 23 to detect vibration of the whole tub based on the signals. The dewatering process is controlled based on the detected vibration information. Thus, noise during dewatering can be prevented.

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 of conventional washing machines which detect the vibration of an outer tub and control the washing operation based on the detected vibration are given below.

As a first example, there is a fully automatic washing machine described in Japanese Patent Application Laid-Open No. 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 for both 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.

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, two magnetic bodies inserted into the coil of the water level sensor 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]

SUMMARY OF THE INVENTION The first conventional example described above is:
Because of the structure in which the position of the center of gravity is changed by moving the outer tub up and down, a vertical mechanism for the entire outer tub is required. Since there are usually four suspensions, four mechanisms are also required. Since the weight of the entire outer tub is several tens of kg even after drainage, the mechanism requires a lifting force of tens of kilograms per unit. 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-mentioned object, a washing machine according to the present invention is characterized in that a rotation speed signal of an inner tub and a rotating blade output from a rotation speed detecting means, The control unit controls the inner tank and the rotary blade based on the upper vibration signal of the upper part of the outer tank output from the vibration detecting means and the lower vibration signal of the lower part of the outer tank output from the second vibration detecting means. Is to perform the rotation control.

Specifically, the washing machine according to the present invention is provided with vibration detecting means above and below the outer tub. The upper detecting means includes a magnet provided above 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, the control means for controlling a series of washing operations such as washing, rinsing, and dehydration acquires the output signal of the vibration detecting means and detects the vibration of the outer tub based on this.

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. During dehydration, the vibration of the upper part of the outer tub and the vibration of the lower part are not necessarily proportional, and both contribute to noise. For this reason, by detecting the vibration state of the entire outer tank from both, the noise caused by this can be more correctly estimated. The control means controls the rotation of the inner tank based on the vibration state. Specifically, since the rotation speed of the inner tank is reduced according to the magnitude of the vibration, the noise level can be suppressed to a certain level or less without excessively deteriorating the dewatering effect, and excessive noise can be prevented.

In summary, according to the present invention, the vibration state of the entire outer tub is detected, and dehydration control is performed based on the vibration state.
Excessive noise during dehydration can be prevented. Furthermore, since the vibration detecting means on the upper part of the outer tub uses the coil of the existing water level detecting means in the washing machine, it can be realized only by adding one magnet.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a washing machine according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a washing machine according to an 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 rotary blade 3 is a rotatable stirring blade provided at the center of the bottom of the inner tank 1, and generates a water flow for washing and rinsing. The rotation mechanism 4 is provided below the outer tub 2,
A mechanism for rotating the inner tank 1 and the rotary wing 3,
It consists of a gear and an electromagnetic clutch.

The suspension rod 5 is a metal rod for suspending the outer tub 2 and supports the lower part of the outer tub 2 with a spring for vibration isolation. The rotating shaft 6 is
It is a rotation axis of the inner tank 1 and the rotary wing 3, and is coupled to the rotation mechanism 4. The rotation mechanism 4 selects and rotates one of the two with a 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 portion of the outer tub 2, and is located substantially directly 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 sensor for converting the water level of the outer tub 1 into an electric quantity, and the electric quantity changes according to the air pressure. The changeover switch 11 is a switch for selecting whether to connect the output terminal of the water level sensor 10 to the first amplification and rectification circuit 12 or to the oscillation circuit 13, and the control unit 14 performs the changeover.

The first amplification and rectification circuit 12 is a circuit that amplifies an output signal of the water level sensor 10, rectifies and smoothes the output signal, and outputs the signal as a DC signal. The oscillation circuit 13 is a circuit that is connected to the water level sensor 10 to generate an AC signal,
The frequency changes according to the electrical 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 includes a first amplifying and rectifying circuit 1
2, and the output signal of the second amplifying and rectifying circuit 24 is obtained from the input terminal of the analog signal, and the output signal of the oscillation circuit 13 is obtained from the input terminal of the digital signal.

The drive circuit 15 is a circuit that obtains a control signal from the control unit 14 and generates electric power for operating the rotation mechanism 4 and electric power for opening and closing the water supply valve 17 and the drainage valve 19 based on the control signal. .

The water supply pipe 16 is connected to a water supply or the like, and
And a water pipe for supplying water to the outer tank 2. Drain pipe 18
Is a water pipe connected to the bottom of the outer tub 2 for draining water in the outer tub 2. The water supply valve 17 and the drainage valve 19 are opening / closing valves provided in the middle of the water supply pipe 16 or the drainage pipe 18, and both perform opening / closing operations 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 second magnet 22 of the outer frame 7.
Is a coil attached in the vicinity of. The second amplifying / rectifying circuit 24 is a circuit having the same function as the first amplifying / 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 of FIG. The magnetic body 102 is inserted into the center of the coil 101. One end of the coil 101 is connected to the changeover switch 11, and the other end is commonly grounded.

The magnetic body 102 is a rod-shaped magnetic body 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. Air chamber 10
The lower part of 4 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. Thereby, the insertion amount of the magnetic body 102 into the coil 101 increases. Since the inductance of the coil 101 changes according to the insertion amount of the magnetic body 102, the inductance changes as a result according to the water level of the outer tub 2.

FIG. 3 shows the first amplifying and rectifying circuit 12 of FIG.
FIG. 3 is a block diagram showing the configuration of 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. Rectification,
The smoothing circuit 12c is a circuit that converts an AC signal into a DC signal corresponding to an effective value. The second amplification and rectification circuit 24 has the same configuration.

FIG. 4 shows an example of the integration circuit 12b of FIG. This is a low-pass filter with a low cutoff frequency.

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 this embodiment is a measurement of the vibration amplitude, and hereinafter the vibration amplitude may be simply referred to as the amplitude. The control unit 14 sets the changeover switch 11 to the a side, and connects the water level sensor 10 to the amplification and rectification circuit 12. Since the first magnet 8 or the second magnet 22 is mounted 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.
In general, the vibration of the outer tub 2 at the time of dehydration is a combination of vibration components in the front-back, left-right, and up-down directions. However, in any of the vibration directions, the relative distance fluctuates, and 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 tub 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, the higher the vibration frequency of the outer tank 2, and the higher the induced voltage. Therefore, in order to obtain a voltage proportional to the vibration amplitude of the outer tub 2 irrespective of the rotation speed of the inner tub 1, the differential characteristics are corrected using the integration circuits 12 b and 24 b.

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 almost 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 characteristics of the induced voltage are canceled by the integrating characteristics of the integrating circuit, and the output voltage of the integrating circuit becomes independent of the rotation speed of the inner tank 1 and the outer tank. 2 is approximately proportional to the vibration amplitude.

FIGS. 5 and 6 show the displacement of the upper part of the outer tub 2 in the front-rear direction and the time of the voltage obtained by amplifying, rectifying, and smoothing the induced voltage of the coil 101 by the first amplifying and rectifying circuit 12 during dehydration. It is an example of a target change. FIG. 5 shows the first amplification,
FIG. 6 shows a case where the integration circuit 12b is omitted from the rectifier circuit 12, and FIG.

The start of dehydration is set to 0 second, and after 120 seconds, the power supply to the motor of the rotating mechanism 4 is cut off. The voltage generated by the coil 101 has a differential characteristic proportional to the temporal change rate of the magnetic flux density inside the coil 101. Therefore, if the amplitude of the outer tub 2 is constant, the higher the vibration frequency, that is, the higher the rotation speed of the inner tub 1, the higher the generated voltage.

In FIG. 5, 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 FIGS. 5 and 6, at the time of dehydration, the rotation speed of the inner tub 1 increases for several tens of seconds from the start of dehydration, and thereafter becomes substantially constant. Thereafter, the increase in the number of revolutions is over,
The period in which it is kept substantially constant may be referred to as a dehydration steady state.

The voltage generated by the coil 101 is amplified, integrated, rectified, and smoothed by the first amplifying and rectifying circuit 12, or the voltage generated by the coil 23 is amplified, integrated and corrected by the second amplifying and rectifying circuit 24. The rectified and smoothed voltage may be referred to as an upper coil voltage or a lower coil voltage, respectively.

FIG. 7 shows the maximum amplitude (maximum value of displacement—minimum value) of the upper or lower part of the outer tub 2 and the average value of the upper coil voltage or the lower coil voltage in the dehydration steady state in a plurality of dehydration experiments. Is the relationship. In the steady state of dehydration,
There is a high correlation between the amplitude and the coil voltage, so that the amplitude can be easily calculated from the coil voltage.

FIG. 8 shows that the weight of the laundry, the first magnet 8 or the second magnet 22, and
It is an example of the relationship with the distance to 3. The weight of the laundry is
Both the weight in the steady state of dehydration and the dry weight are shown.

Since the outer tub 2 is supported by the hanging bar 5 having a spring, as the weight of the laundry increases, the spring is deformed and the outer tub 2 sinks. For this reason, the distance from the first magnet 8 to the coil 101 increases according to the weight. Further, as the outer tank 2 sinks, the position of the second magnet 22 also lowers. Since the coil 23 is fixed to the outer frame 7, the distance between the magnet and the coil changes as the outer tub 2 sinks.

FIG. 9 shows an example of the relationship between the weight of the laundry and the upper coil voltage and the lower coil voltage when the amplitude of the outer tub 2 is constant. Since the distance between the magnet and the coil changes according to the weight of the laundry, the voltage changes accordingly. Therefore, in order to calculate the upper and lower amplitudes of the outer tub 2 from the voltage, it is necessary to detect the weight of the laundry and correct the voltage based on the relationship shown in FIG.

Next, a method for determining the weight of the laundry will be described with reference to FIG. This is from the start of dehydration,
In this method, the weight is determined based on the time until the rotation speed of the inner tank 1 reaches a fixed value (for example, 150 rpm).

If the rotation force of the rotation mechanism 4 is the same, the larger the inertial mass in the inner tank 1, the slower the increase in the number of rotations and the longer the time. The figure shows an example of the distribution of the time from the start of dehydration to the rotation speed reaching 150 rpm for six types of laundry weight. It can be seen that there is almost no overlap in the distribution of the time at each weight, and the weight of the laundry can be determined in six stages from the time.

Hereinafter, the noise during dehydration will be described with reference to FIGS.

FIG. 11 is an example in which a representative pattern of the mass distribution of the laundry in the inner tub 1 which occurs during dehydration in actual washing is simulated by an equivalent mass. The upper unbalance mass 25 and the lower unbalance mass 26 are
Is an object having a predetermined mass, which is attached to an upper portion and a lower portion of the inner surface of the vehicle. These simulate the bias of the laundry.

The load mass 27 is an object having a predetermined mass whose center of gravity coincides with the rotation axis of the inner tank 1. This simulates the weight of the laundry. (A), (b), (c), and (d) in the figure are patterns in which the unbalance mass is only the upper portion, only the lower portion, the same direction in the vertical direction, and the opposite direction in the vertical direction.

As described above, in actual washing, the inner tub 1
The vibration mode (vibration mode) of the outer tub 2 during dehydration varies depending on the position and size of the bias of the laundry in the interior, and the noise generating portion and the noise level differ depending on the vibration mode. Therefore, in order to perform control for suppressing noise during dehydration, it is necessary to detect the vertical vibration of the outer tub 2 and identify the vibration mode from this.

FIG. 12 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 in the pattern (a) of FIG. The dehydration start time is set to 0, and the current of the motor is cut off at time T0. After the time T, the rotation speed is substantially constant, and from the time T to T0, the dehydration is in the steady state. The noise level increases with the rotation speed and becomes maximum in the steady state of dehydration.

FIG. 13 to FIG. 16 show the equivalent mass in the pattern of (a) to (d) above in the inner tub 1 to perform the dehydration operation. , Lower amplitude, and upper and lower coil voltages over time.

As shown in FIG. 1, the outer tub 2 has a structure in which the outer tub 2 is vibration-isolated and supported at four locations by a hanging rod 5 having a spring. Therefore, resonance occurs at a specific oscillation period determined by the relationship between the total mass supported by the hanging bar 5 and the spring constant, and the amplitude sharply increases. Actually, the resonance phenomenon occurs twice immediately after the start of dehydration. The first resonance is a phenomenon in which the entire outer tank 2 rotates while being eccentric in the same direction, and is called primary resonance. The second resonance is a phenomenon in which the entire outer tub 2 rotates while tilting, and is called secondary resonance.

In FIG. 13 (pattern (a), upper unbalance mass 25 only) and FIG. 14 (pattern (b), lower unbalance mass 26 only), one of the outer tubs 2 that occurs immediately after the start of dehydration. The maximum value occurs twice in each amplitude and voltage due to the secondary resonance and the secondary resonance. In FIG. 14, the upper coil voltage at the time of steady dehydration is very low.

In FIG. 15 (pattern (c), upper and lower unbalance masses are in the same direction), the maximum value due to the primary resonance is clear, but the maximum value due to the secondary resonance is unclear. Conversely, in FIG. 16 (pattern (d), the upper and lower unbalance masses are opposite), the maximum value due to the primary resonance is unclear, but the maximum value due to the secondary resonance is clear.

As described above, the primary and secondary coil voltages of the upper and lower coils
It is possible to determine which of the patterns (a) to (d) the vibration state of the outer tank 2 is based on the maximum value due to the next resonance and the value after that. This method will be described later.

FIGS. 17 and 18 respectively show the average value of the noise level at the time of steady dehydration in each of the patterns,
It is an example of the relationship with the average value of an upper and lower coil voltage. FIG.
7, in the case of the pattern (b) (only the lower unbalanced mass 26), the upper coil voltage is very low irrespective of the noise level, but otherwise, there is a difference between the noise level and the upper and lower coil voltages. There is a high correlation.

However, the inclination of the approximate straight line is slightly different depending on the pattern. Therefore, if it is determined which pattern the vibration state of the outer tub 2 is close to, the noise level can be estimated from the upper and lower coil voltages in the dehydration steady state.

Hereinafter, a control method during dehydration will be described.
This will be described with reference to FIGS.

In order to keep the noise level below a certain value, a threshold is provided for the noise level. In the examples of FIGS. 17 and 18, for example, the threshold is set to L1 = 54 dB. Then, on the approximate straight line, the upper coil voltages Vua, Vu corresponding to L1
c, Vud, and lower coil voltages Vda, Vdb, Vdc, Vdd are determined. Based on which of the patterns the vibration state of the outer tub 2 is closer to, select one of these patterns,
The threshold values of the upper and lower coil voltages are V1 and V2.

FIG. 19 shows the inner tub 1 in the steady state of dehydration.
It is an example of the relationship between the number of rotations and the noise level. Each time the rotational speed is reduced by 100 rpm, the noise level decreases by about 3 dB. Therefore, when the upper and lower coil voltages exceed the threshold value during steady state of dehydration, if the rotation speed is reduced in accordance with the degree of the increase, the noise level during dehydration can be suppressed to the threshold value or less.

A method of controlling the rotation of the inner tank 1 based on the upper and lower coil voltages will be described with reference to FIG.

At the start of dehydration, t = 0. The upper and lower coil voltages Vu and Vd are compared with the threshold value V1 or V2. However, immediately after the start of dehydration, Vu and Vd have large values due to the primary and secondary resonances. Therefore, the control unit 14 performs the comparison after the rotation speed of the inner tub 1 reaches a certain value.

If Vu> V1 or Vd> V2, the control unit 14 calculates the upper limit rotational speed candidate ru or rd according to ΔVu = Vu−V1 or ΔVd = Vd−V2. An example is shown in FIG. If Vu ≦ V1 or Vd ≦ V2, it is assumed that ru or rd = maximum rotational speed rmax (for example, 1000 rpm).

If Vu> V1 or Vd> V2,
ΔVu or ΔVd decreases ru or rd accordingly. In the example shown in the figure, ru and ΔVu, rd and ΔVd are linearly related, and ru = rmax−c1 · ΔVu, rd = rmax−c2 · ΔVd
And The coefficients c1 and c2 are shown in FIG. 17 and FIG. 18, the relationship between the noise level and the upper and lower coil voltages, and FIG.
Determined from the relationship between the noise level and the rotation speed.

For example, in FIG. 19, the relationship between the rotational speed r and the noise level L is L = k (= 3 dB / 100 rpm) · r + e (constant)
Then, the rotation speed change Δr = (1 / k) · ΔL. In the relationship between the noise level L and the upper coil voltage Vu in FIG. 17, the pattern (a) is used, and the approximate straight line is Vu =
If cua · L + f (constant), ΔL = (1 / cua) · ΔVu
Becomes From the above, c1 = (1 / k) · (1 / cua). Similarly, for c2, c2 = (1 / k). (1 / cda, etc.).

Returning to FIG. 20, the description will be continued. The control unit 14 selects either ru or rd based on the vibration state of the outer tub 2 and sets the upper limit rotational speed r1. The figure shows the case where r1 = ru. Assuming that V exceeds V1 at t = t1, t ≦ t
At 1, r1 = rmax. When t> t1, r1 is set according to .DELTA.V.
Is determined. Assuming that r reaches r1 at t = t2, the control unit 14 thereafter controls the rotation of the inner tank 1 so as to keep the rotation speed r of the inner tank 1 near r1.

One specific example of performing the above-described rotation control is as follows.
The operation of the control unit 14 will be described with reference to the flowchart of FIG. This example is a method in which the lower one of ru or rd is set as the upper limit rotational speed r1. At the start of dehydration, the control unit 14 starts energizing the motor of the rotation mechanism 4. The initial value of the rotational speed upper limit r1 is the maximum rotational speed rmax.

Then, the laundry weight (cloth amount) is determined by the above-described method (s-1), and the threshold values V1 and V2 of the upper and lower coil voltages are corrected based on the result. Here, V1 is the largest Vua among Vua, Vuc, and Vud in FIG.
V2 is Vdb in the case of only the lower unbalance mass 26 from Vda to Vdd in FIG.
2).

Thereafter, until the dehydration is stopped, the control unit 14 acquires the upper and lower coil voltages Vu and Vd at a constant cycle (s-3). When the rotation speed r of the inner tank 1 reaches a fixed value ra (for example, 500 rpm) (s-4), the control unit 14 compares r with r1. This will be described later in detail.

Since r1 = rmax at first, r1 >> r is satisfied (s-5). Then, the control unit 14 compares the upper coil voltage Vu with the threshold value V1 (s-6), and if Vu> V1, the difference ΔVu
, The upper limit rotation speed candidate ru is determined. Specifically, as described above, ru = rmax−c1ΔVu, c1 = (1 / k) · (1
/ cua) (s-7). If Vu is less than V1, (s-
6), ru = rmax is set (s-8).

Further, the lower coil voltage Vd is compared with the threshold value V2 (s-9). If Vd> V2, the upper limit rotation speed candidate rd is determined according to the difference ΔVd. Specifically, as described above, rd = rmax-c2.DELTA.Vd, and c2 = (1 / k) .multidot. (1 / cdb) (s-10). If Vd is less than V2 (s-9), r
Let d = rmax (s-11). Then, the smaller one of ru and rd is set as the upper limit rotational speed r1 (s-1).
2).

Then, the control unit 14 compares the rotational speed r of the inner tank 1 with r1 (s-13), and performs control to decrease r if it exceeds r1. Specifically, when r exceeds r1, the power supply to the motor is cut off (s-14). If r is equal to or smaller than r1, control is performed to increase r. Specifically, when r is lower than r1 by a certain amount or more, the motor is energized (s
-14).

By controlling the rotation speed to decrease and increase, it is possible to maintain r near r1 after increasing r to r1.
When r reaches near r1 and the difference between the two becomes very small (s-5), it is determined that the dehydration steady state has been reached.
The control unit 14 fixes the value of r1 to the value at that time and updates r1 from (s-6) to (s-14) or (s-15).
The operation up to is omitted.

Until the dehydration time ends or a dehydration error such as the user opening the lid during dehydration occurs (s-1).
6), the control unit 14 repeats the operation from (s-5) to (s-15).

According to this embodiment, the rotation control of the inner tank 1 is performed with the lower one of the upper limit rotation speed candidates calculated from the upper and lower amplitudes of the outer tank 2 as the upper limit rotation speed. Even in the vibrating state, the number of revolutions of the inner tub 1 is reduced so that the noise level is surely equal to or lower than a certain value, so that excessive noise can be prevented.

In particular, even when the mass is unevenly distributed only in the lower part of the inner tank 1 and the amplitude of the upper part is very small as in the above-mentioned pattern (b), excessive noise can be obtained by controlling the rotation based on the lower part amplitude. Can be prevented.

Next, another example of controlling the rotation of the inner tank 1 will be described with reference to FIGS. In this example, the vibration state of the outer tank 2 is the pattern (a) of the mass distribution described above.
In this method, it is determined which of the vibrations is closer to (d), and the rotation of the inner tank 1 is controlled based on the judgment. Hereinafter, the fact that the vibration state of the outer tub 2 is close to the vibrations according to the patterns (a), (b), (c), and (d) is referred to as vibration modes A, B, respectively.
They may be referred to as C and D.

As shown in FIGS. 13 to 16, the upper and lower coil voltages during dehydration characteristically fluctuate according to the vibration mode. Therefore, the vibration mode is determined by comparing the maximum value of the voltage at the time of primary and secondary resonance of the outer tank 2 and the value after a certain time has elapsed.

As shown in FIG. 23, the maximum values of the upper coil voltage at the time of primary and secondary resonance are pu1, pu2, and the maximum values of the lower coil voltage are pd1, pd2, respectively. Specifically, assuming that the dehydration start time is time t = 0, the maximum value of the primary resonance is 0 <t ≦ T1 at any laundry weight.
T1 and T2 are determined such that the maximum value of the secondary resonance occurs within T1 <t ≦ T2, and the maximum values of the voltages at 0 <t ≦ T1 are pu1, pd1, and T1 <t ≦ The maximum values of the voltages at T2 are pu2 and pd2.

When the rotation speed r of the inner tank 1 reaches a constant value, for example, ra = 500 rpm, t = T3.
The lower coil voltages are pu3 and pd3, respectively. These values are approximately equal to the values of Vu and Vd at the time of steady dehydration. The determination of the vibration mode is made by comparing pu1 to pu3 and pd1 to pd3. The specific determination method will be described later with reference to FIG.
This will be described with reference to FIG.

A specific control method will be described with reference to the flowchart of FIG. The control unit 14 controls the period from the start of dehydration to the stop of dehydration.
The upper and lower coil voltages Vu and Vd are obtained at a constant cycle (u−
1). Then, the cloth amount is determined (u-2).

Then, the control unit 14 obtains the maximum values pu1, pd1 (u-3) and Vd2 of Vu and Vd at the time of the primary resonance by the above-described method.
The maximum values pu2 and pd2 at the time of the next resonance are detected (u-4). When the rotation speed r of the inner tank 1 reaches the fixed value ra (u-5), the values of Vu and Vd at this time are set as pu3 and pd3, respectively (u-6). Then, the control unit 14 determines that pu1 to pu3 and p
The vibration mode of the outer tub 2 is determined based on d1 to pd3 (u-7).

The details of the determination method will be described with reference to the flowchart of FIG. The deviation of the cloth in the inner tank 1 is small, and pu1 to pu3 and pd1 to pd3 are all
When the value is small and does not exceed the threshold value Vtu or Vtd (v-1), it is difficult to determine the vibration mode, and the mode is temporarily set to mode A (v-2).

In this case, there is no possibility that excessive noise is generated during the steady state of dehydration. If the threshold is exceeded (v−
1), qu = pu3 / max (pu1, pu2), and qd = pd3 / m
Calculate ax (pd1, pd2). qu and qd are relative values of Vu or Vd when r = ra with respect to the maximum value of Vu or Vd at the time of resonance (v-3). Then, the up / down ratio Q = qu / qd of the relative value is calculated (v-4).

When Q is large (for example, more than 1.5), the relative value qu >> V of Vu at the time of r = ra shown in FIG.
Mode A is assumed to be close to the pattern of the relative value qd of d (v-6). When Q is small (for example, less than 0.7), it is assumed that the pattern is close to the pattern of qu << qd shown in FIG. 14, and the mode is set to mode B (v-7).

If Q is around 1, (v-5)
The mode is determined by comparing the maximum values at the time of the secondary resonance. When the primary maximum value is clearly larger than the secondary maximum value in both the upper and lower directions (for example, the ratio is 1.2) (v-8), only the primary maximum value shown in FIG. (V-9).

When the primary maximum value is clearly smaller than the secondary maximum value (for example, a ratio of 0.8) (v-8), only the secondary maximum value shown in FIG. D. When the primary and secondary maxima are approximately equal (v-8), mode A is assumed to be rather close to the pattern of FIG. 13 (v-11).

Returning to FIG. 24, the description will be continued. When the vibration mode is A, C, or D (u-8), the control unit 14 sets the upper limit rotational speed r1 based on the upper coil voltage Vu. First, one of the threshold values Vua, Vuc, and Vud according to the vibration mode is compared with Vu, and if Vu exceeds the threshold value, (u−
9) Set r1 according to the difference between Vu and the threshold.
Specifically, r1 = rmax−c1ΔVu, c1 = (1 / k) · (1 /
cua, 1 / cuc, or 1 / cud) (u-1
0).

If Vu is less than the threshold value (u-9),
It is assumed that r1 = rmax (u-11). When the vibration mode is B (u-8), the upper limit rotational speed r1 is determined based on the lower coil voltage Vd.
Set. First, Vd is compared with a threshold value Vdb. If Vd exceeds the threshold value (u-12), r1 is set according to the difference between Vd and the threshold value. Specifically, r1 = rma
x−c2ΔVd, c2 = (1 / k) · (1 / cdb) (u−1
3).

If Vd is less than the threshold value, (u-1)
2), r1 = rmax (u-11). And control unit 1
4 performs control to keep r near r1. Specifically, r>
If r1 (u-14), lower r (u-15),
If r is lower than r1 by a certain amount or more, r is increased (u-1).
6). Until the dehydration ends or a dehydration error occurs (u-
17), the control unit 14 repeats the operations from (u-8) to (u-17).

According to this embodiment, before the dehydration steady state is reached, the vibration mode of the outer tub 2 is determined, and the rotation speed reduction law according to the vibration mode is selected, and the rotation control is performed based on this.
Compared to the above example, the noise level can be suppressed to a certain level or less without unnecessarily lowering the rotation speed.

In the above embodiment, an example has been described in which the magnets provided in the outer tank 2 and the coils provided in the outer frame 7 near the magnets are used as the vibration detecting means on the upper and lower parts of the outer tank 2. . Not limited to this, the acceleration, speed,
Other means for detecting the displacement, for example, using an acceleration sensor such as a piezoelectric element provided on the upper and lower parts of the outer tank 2 and a gyro,
Similarly, vibration can be detected, and the effect of suppressing noise during dehydration can be obtained.

[0096]

According to the present invention, since the vibration detecting means is provided on the upper and lower portions of the outer tub to detect the vibration state of the entire outer tub, it is possible to completely detect the vibration which causes noise during dehydration.

At the time of spin-drying, the upper limit value of the rotation speed of the inner tub is set based on the rotation speed reduction rule according to the vibration state, and control is performed to bring the rotation speed of the inner tub closer to the upper limit value. The noise level during dehydration can be suppressed below a certain level without impairing the dehydration effect more than necessary.

[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 circuit diagram illustrating an example of the integration circuit of FIG. 3;

FIG. 5 is a diagram showing an example of a temporal change in the amplitude of the upper part of the outer tank and the output voltage of the amplification and rectification circuit, showing a case without an integration circuit.

FIG. 6 is a diagram showing an example of a temporal change in the amplitude of the upper portion of the outer tank and the output voltage of the amplification and rectification circuit, showing a case where an integration circuit is provided.

FIG. 7 is a diagram showing the relationship between the amplitude of the upper and lower parts of the outer tank and the coil voltage.

FIG. 8 is a diagram illustrating a relationship between the weight of laundry and a distance between a magnet and a coil.

FIG. 9 is a diagram illustrating a relationship between the weight of laundry and a coil generation voltage.

FIG. 10 is a diagram illustrating an example of a time required for the rotation speed of the inner tank to reach 150 rpm.

FIG. 11 is a diagram simulating a mass distribution of laundry in the inner tub.

FIG. 12 is a diagram illustrating an example of a temporal change of a noise level, a coil voltage, and a rotation speed of an inner tub during dehydration.

FIG. 13 is a diagram showing an example of the temporal change of the amplitude of the outer tub and the coil voltage at the time of dehydration, showing the case of only the upper part.

FIG. 14 is a diagram showing an example of temporal changes in the amplitude of the outer tub and the coil voltage during dehydration, and shows the case of only the lower part.

FIG. 15 is a diagram showing an example of temporal changes in the amplitude of the outer tub and the coil voltage during dehydration, showing a case where the vertical direction is the same.

FIG. 16 is a diagram showing an example of a temporal change in the amplitude of the outer tub and the coil voltage during dehydration, showing a case where the direction is upside down.

FIG. 17 is a correlation diagram between a noise level during dehydration and an upper coil voltage.

FIG. 18 is a correlation diagram between a noise level during dehydration and a lower coil voltage.

FIG. 19 is a diagram showing an example of the relationship between the rotation speed of the inner tub and the noise level during dehydration.

FIG. 20 is a diagram illustrating an example of a method of controlling rotation of an inner tank during dehydration.

FIG. 21 is a diagram illustrating an example of an upper limit rotation speed of an inner tub during dehydration.

FIG. 22 is a flowchart showing the operation of the control unit during dehydration.

FIG. 23 is a diagram illustrating an example of a temporal change of a coil voltage during dehydration.

FIG. 24 is a flowchart showing the operation of the control unit at the time of dehydration.

FIG. 25 is a flowchart showing a method of determining the vibration mode of the outer tub 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, 25 ... upper unbalanced mass, 26
... Lower unbalance mass, 27 ... Load mass, 101 ... Coil, 102 ... Magnetic material, 103 ... Film surface, 104 ... Air chamber, 105 ... Spring

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Toshifumi Koike 502 Kandachi-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. F-term (reference) in Hitachi, Ltd.Electrical Equipment Division 3B155 AA06 BA03 CA16 CB06 KA02 KA19 KA35 KB07 KB08 LA02 LA04 LB02 LB17 LC07 LC29 LC32 LC33 LC34 MA01 MA03 MA05 MA06

Claims (5)

[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 and a rotatable blade provided at the bottom of the inner tank, a rotating means for rotating the inner tank and the rotatable blades, and detecting a rotation speed of the rotating means, Rotation number detection means for outputting a rotation number signal of the detected rotation number; first vibration detection means for detecting vibration of the upper part of the outer tub and outputting an upper vibration signal of the detected vibration; A second vibration detection unit that detects vibration of a lower portion of the tank and outputs a lower vibration signal of the detected vibration, and acquires the upper vibration signal, the lower vibration signal, and the rotation speed signal, and A washing machine comprising: control means for controlling rotation of the rotating means based on the upper vibration signal, the lower vibration signal, and the rotation speed signal. 2. The apparatus according to claim 1, wherein the control means identifies a vibration mode of the outer tub based on the upper vibration signal and the lower vibration signal, and rotates the rotation means according to the vibration mode. A washing machine characterized by performing control. 3. The control device according to claim 1, wherein the control means sets an upper limit value of a rotation speed of the rotation device in accordance with the upper vibration signal and the lower vibration signal, and the rotation speed exceeds the upper limit value. A washing machine for controlling the rotation of the rotating means so as not to cause the washing machine to rotate. 4. The apparatus according to claim 1, further comprising weight detection means for detecting the weight of the laundry in said inner tub, wherein said control means comprises:
Obtain an output signal of the weight detected by the weight detecting means,
A washing machine wherein the detection result of the vibration is corrected based on the obtained output signal. 5. The apparatus according to claim 1, wherein the first vibration detecting means is fixed to a coil built in a water level detecting means for detecting a water level of the outer tub, and is fixed to the outer tub near the water level detecting means. A washing machine characterized by comprising a magnet.