JP2000350886A - Washing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To spray water of nearly the same volume into a washing/spin-dry basket even if there is difference in the volume of the washing water in the washing/spin-dry basket by controlling the rotation of the washing/spin-dry basket while monitoring the current flowing to a motor of a washing machine which removes the dirt of clothes by rotationally driving the washing/spin-dry basket and circulating the washing water. SOLUTION: The washing/spin-dry basket 2 freely rotatably disposed in an outer tank 1 is driven by a motor 5 and the water level of the washing/ spin-dry basket 2 is detected by a water level detecting means 10. The control means controls the motor 5 to control strokes and has a washing stroke of rotating the washing/spin-dry basket and spraying the washing water from between the outer tank 1 and the washing/spin-dry basket 2 into the washing/ spin-dry basket 2. The control means is so constituted as to approximately constantly control the current value of the motor 5 according to the water level of the washing/dehydrating tank 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a washing machine for rotating a washing / dewatering tub and circulating washing water to remove dirt from clothes.

[0002]

2. Description of the Related Art Conventionally, a washing machine has been constructed as shown in FIGS. Hereinafter, the configuration will be described.

As shown in FIG. 7, an outer tub 80 includes a washing and dewatering tub 82 in which a stirring blade 81 is rotatably arranged at the bottom, and is suspended from a washing machine outer frame 84 by a hanging rod 83. . The motor 85 is provided with a stirring blade 81 or a washing and dewatering tub 82 via a V-belt 86 and a speed reduction mechanism / clutch 87.
Drive. The drain valve 88 drains the washing water in the washing and dewatering tub 82, and the water supply valve 89 supplies water to the washing and dewatering tub 82.

[0004] A fluid balancer 89 for reducing vibration during dehydration is provided above the washing and dewatering tub 82, and a lid 90 is provided above the washing and dewatering tub 82.

[0005] The water level detecting means 91 detects the water level by converting the water pressure at a connection (trip point) 92 at the lower part of the outer tub 80 into an electric frequency. The rotation speed detecting means 93 is attached to the motor 85, outputs a pulse corresponding to the rotation speed of the motor 85, and outputs the pulse to the control device 9
4 is input.

The control device 94 includes a motor 85, a drain valve 88,
And the like, and sequentially controls a series of steps of washing, rinsing, and dehydrating, and is configured as shown in FIG. 8, and is controlled by a control means 95 including a microcomputer and a signal from the control means 95. Motor 85, drain valve 88,
Power switching means 96 for controlling water supply valve 89 and the like
And operation means 98 including key switches disposed in an operation panel 97, and display means 99 including a display device such as a light emitting diode. Here, 100 is an AC power supply, and 101 is a phase advance capacitor of the motor 85.

The operation of the above construction will be described. After the laundry and the detergent are put into the washing and dewatering tub 82, a water supply valve 89 is provided.
To supply water to the set water level in the washing and dewatering tub 82,
Then, by rotating the stirring blade 81, mechanical force is applied to the clothes to remove dirt, and even during rinsing, water is supplied to the set water level in the washing machine and dewatering tank 82, and the stirring blade 81 is rotated. Rinse clothing by driving.

[0008]

In such a conventional configuration, the agitating blade 81 is turned to the right or left to apply mechanical force to the garment to remove dirt, so that the garment is damaged and entangled. Was.

On the other hand, the washing and spin-drying tub 82 is driven to rotate by a motor 85 to raise the water in the washing and spin-drying tub 82 between the washing and spin-drying tub 82 and the outer tub 80, and When water is sprinkled inside the washing and dewatering tub 82 over the upper end portion of the washing and dewatering tub 82, the clothes can be washed with little damage and without tangling, but if this control is to be performed by an induction motor, the torque of the motor 85 is reduced. There was also a problem that it was insufficient and could not actually be controlled.

Further, a DC brushless motor is used as the motor 85, and power is supplied to the DC brushless motor by an inverter to control the speed of the washing and dewatering tub 82 at a constant speed.
Just trying to circulate the washing water has the problem that the motor current flows too much, such as when the amount of clothes is too large, and the permanent magnet provided on the rotor constituting the DC brushless motor is demagnetized. Was.

Further, if only a constant rotation speed is controlled, the amount of water sprinkled into the washing and dewatering tub 82 varies depending on the amount of washing water, so that it is not possible to sufficiently clean clothes, There is also a problem that a large amount of bubbles may be generated.

The present invention solves the above-mentioned conventional problems. The present invention controls the rotation of the washing and dewatering tub while monitoring the current flowing through the motor. The purpose is to enable almost the same amount of water to be sprinkled in the dewatering tank.

[0013]

In order to achieve the above object, the present invention drives a washing and dewatering tub rotatably provided in an outer tub by a driving means, and detects a water level of the washing and dewatering tub by a water level detecting means. The control means controls the driving means to control the stroke, and rotates the washing and dewatering tub to supply the washing water from between the outer tub and the washing and dewatering tub into the washing and dewatering tub. It has a washing step of spraying water, and is configured to control the current value of the driving means to be substantially constant according to the water level of the washing and dewatering tub.

Thus, the rotation of the washing and dewatering tub is controlled while monitoring the current flowing through the driving means, so that even if the amount of washing water in the washing and dewatering tub is different, almost the same amount of water is stored in the washing and dewatering tub. You can water it.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION
A washing and dewatering tub rotatably provided in the outer tub, a driving means for driving the washing and dewatering tub, a water level detecting means for detecting a water level of the washing and dewatering tub, and a process for controlling the driving means. Control means for controlling, the control means has a washing step of rotating the washing and dewatering tub and spraying washing water into the washing and dewatering tub from between the outer tub and the washing and dewatering tub. The current value of the driving means is controlled to be substantially constant according to the water level of the washing and dewatering tub, and the rotation of the washing and dewatering tub is controlled while monitoring the current flowing through the driving means, and By rotating the washing and dewatering tub according to the water level in the washing and dewatering tub and rotating the washing and dewatering tub, even if the amount of washing water is different, almost the same amount of water is sprinkled into the washing and dewatering tub. can do. In addition, since a certain amount of current can be prevented from flowing through the driving unit, it is possible to prevent the permanent magnet provided on the rotor in the motor constituting the driving unit from being demagnetized.

According to a second aspect of the present invention, in the first aspect of the present invention, there is provided a cloth amount detecting means for detecting the amount of clothes in the washing and dewatering tub, and the control means includes an output of the cloth amount detecting means. Thus, the current value of the driving means is controlled to be substantially constant, so that even if there is a difference in the amount of clothes in the washing and dewatering tub, it is possible to spray substantially the same amount of water in the washing and dewatering tub. it can.

According to a third aspect of the present invention, in the first or second aspect of the present invention, an inverter comprising a switching element for supplying power to the driving means and a current value corresponding to a current flowing through the driving means are detected. Current detection means, wherein the control means compares the output value of the current detection means with a current set value, controls the conduction ratio of the switching element, and controls the rotation speed of the drive means. Yes, watering into the washing and dewatering tub can be accurately controlled.

[0018]

An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the outer tub 1 includes a washing and dewatering tub 2 rotatably disposed therein, and a hanging bar 3 suspends a washing machine outer frame 4. The motor (driving means) 5
It is composed of a DC brushless motor and has a clutch and reduction mechanism 6
The washing and dewatering tub 2 or the stirring blade 7 rotatably disposed at the inner bottom of the washing and dewatering tub 2 is driven to rotate. The cover body 8 forms a water discharge section provided on the upper part of the outer tub 1.

The water supply valve 9 is for supplying water to the washing and dewatering tub 2, the water level detecting means 10 is for detecting the water level in the outer tub 1, and the drain valve 12 is for water supply in the outer tub 1. Drain the washing water.

As shown in FIG. 2, the motor 5 includes a stator (not shown) having a three-phase winding 13 and a rotor (not shown) having a two-pole permanent magnet on a ring. And a first winding 13 constituting a three-phase winding 13 on the stator.
a, the second winding 13b, and the third winding 13c.

The motor 5 is driven by an inverter 14, and the inverter 14 is composed of a switching element composed of a parallel circuit of a power transistor (IGBT) and a reverse conducting diode as shown in FIG. A series circuit of a first switching element 14a and a second switching element 14b, a series circuit of a third switching element 14c and a fourth switching element 14d, and a fifth switching element 14e and a sixth switching element 14f. The switching element is composed of a series circuit and the series circuit of the switching elements is connected in parallel.

Here, both ends of the series circuit of the switching elements are input terminals, a DC power supply is connected, and output terminals are connected to connection points of two switching elements constituting the series circuit of the switching elements. The output terminal is 3
The U terminal, which is connected to the three terminals of the phase winding 13, the U terminal, the V terminal, and the W terminal, and is turned on and off by a combination of two switching elements constituting a series circuit of the switching elements,
The V terminal and the W terminal are set to three states: positive voltage, zero voltage, and release.

The switching element is turned on / off by a control means 16, a first rotation speed detection means 17a, a second rotation speed detection means 17b, and a third rotation speed detection means 17c via a drive circuit 15. The configured rotation speed detecting means 17
Is controlled by First rotation speed detecting means 17
a, the second rotational speed detecting means 17b and the third rotational speed detecting means 17c are disposed on the stator so as to face permanent magnets provided on the rotor of the motor 5 at intervals of 120 electrical degrees. I have.

As shown in FIG. 3, while the motor 5 makes one rotation, the first rotation speed detecting means 17a, the second rotation speed detecting means 17b, and the third rotation speed detecting means 17c are respectively shown in FIG. At the timing shown, the high-low signal is set to 1
Output pulse. The control means 16 detects the timing of the arrow shown in the figure, that is, when any of the three rotation speed detecting means changes the signal from high to low and from low to high. Hereinafter, the output of the pulse signal from the rotation speed detecting means 17 means this timing.

The rotational speed detecting means 17 is constituted by an element for detecting the state of a magnetic field such as a Hall IC, and outputs a high signal when facing the N pole surface of a permanent magnet provided on the rotor. When facing the extreme surface, a low signal is output (or vice versa). FIG. 3 shows an example of the ON / OFF timing of the switching elements 14a to 14f for rotating the motor 5.

The switching elements 14a to 14f change the ON / OFF state based on the signal of the rotation speed detecting means 17 so that the U terminal, the V terminal, and the W terminal become positive voltage, zero voltage, and release. State, and a current is applied to the first winding 13a, the second winding 13b, and the third winding 13c to create a magnetic field,
Rotate the rotor.

The control means 16 is composed of a microcomputer, and has a first rotation speed detection unit 17a, a second rotation speed detection unit 17b, and a third rotation speed detection unit 17b in accordance with the rotation direction of the washing and dewatering tub 2.
The switching elements 14a to 14f corresponding to the output signal of the rotation speed detecting means 17c are turned on and off to control the motor 5. As for the rotation speed control, the rotation speed of the motor 5 or the washing and spin-drying tub 2 is detected by the pulse period of the rotation speed detection means 17, and the rotation speed data is fed back to determine the energization ratio of the switching elements 14a to 14f. By making adjustments, control is performed to achieve the target rotation speed.

The current detecting means 18 uses a resistor in this embodiment, and detects the input current value of the inverter 14 based on the voltage across the resistor. Reference numeral 19 denotes a commercial power supply, which is connected to the inverter 1 via a DC power supply exchange device including a diode bridge 20, a choke coil 21, and a smoothing capacitor 22.
4 is connected. The input setting means 23 sets a driving course and the like.

The control means 16 controls the operations of the clutch / deceleration mechanism 6, the water supply valve 9, and the drain valve 12 via the load driving means 24, and sequentially controls a series of steps of washing, rinsing, and dewatering. However, this is only an example, and the configuration of the motor 5,
The configuration of the inverter 14 is not limited to this.

When the motor 5 is constituted by a DC brushless motor, the value of the current flowing through the motor 5 and the torque of the motor 5 are in a proportional relationship. As the value of the current flowing through the motor 5 increases, a higher torque can be obtained from the motor 5. In the washing machine having the above structure, the torque from the motor 5 is transmitted to the washing and dewatering tub 2, and the rotation speed of the washing and dewatering tub 2 is determined by the sum of the torque, the amount of washing water in the washing and dewatering tub 2, and the amount of clothes. Is decided.

The current value flowing through the motor 5 (motor torque)
4A, there is a relationship shown in FIG. 4A between the amount of clothes and the amount of washing water circulating in the washing and dewatering tub 2 when. Curve a in FIG. 4A shows the relationship between the amount of clothing and the amount of circulating water when the amount of washing water is at the middle water level, and curve b shows the amount of clothing and the amount of circulating water when the amount of washing water is at the low water level. Curve c shows the relationship between the amount of clothing and the amount of circulating water when the amount of washing water is at a small water level.

When the circulating water amount is less than Jb, the circulating water amount is small, so that the washing performance is low. When the circulating water amount is more than Ja, the circulating water amount is large, and foaming by the detergent increases.

As shown in FIG. 4A, the circulating water amounts Jb and Ja
If there is a sufficient difference, the motor 5 may be driven with a constant current value even if the amount of washing water or the amount of clothes fluctuates. However, in order to further improve the washing performance, the current of the motor 5 is increased to increase the circulation. When the amount of water is increased, as shown in FIG.
And the difference between Ja and Jb becomes narrower, and problems such as foaming of the detergent occur depending on the amount of washing water and the amount of clothes.

Therefore, by controlling the current of the motor 5 in accordance with the amount of washing water detected by the water level detecting means 10 and the result of detection of the amount of laundry described later, even if the amount of washing water or the amount of clothing fluctuates, Washing performance is high and washing with less foaming of detergent can be realized.

As an example of controlling the rotation torque of the motor 5 by using a control command from the control means 16 using the inverter 14, the following method is available. As described above, since the torque of the motor 5 and the value of the current flowing through the motor 5 are in a proportional relationship, by controlling the value of the current flowing through the motor 5,
It will control the torque. Each time a pulse signal is input from the motor 5, a current value is detected by the current detecting means 18, and based on this current value, the switching elements 14a to 14a
It can be realized by changing the on / off ratio of 14f.

First, in order to detect the value of the current flowing through the motor 5, the output signal detected by the current detecting means 18 is input to the control means 16 each time the rotating speed is determined by the rotating speed detecting means 17. From this signal, the value of the current flowing through the motor 5 (motor torque) is determined.

The detected current value is compared with a target current value (set current value). If the current is larger than the set current value, the duty ratio of the switching elements 14a to 14f of the inverter 14 is determined. It is made smaller to reduce the current flowing through the motor 5 and reduce the rotational torque. If the current is smaller than the set current value, the inverter 1
4, the energization ratio of the switching elements 14a to 14f is increased, the current flowing through the motor 5 is increased, and the rotational torque is increased.

In order to improve the response speed of the control as compared with this control method, the duty ratio of the switching elements 14a to 14f is not operated only by the difference (deviation) between the current value and the set current value. In consideration of the amount of change in the current value from the time of the previous measurement, a control method in which the operation amount of the duty ratio of the switching elements 14a to 14f is determined by fuzzy control based on the deviation amount and the amount of change is effective.

The operation of the above configuration will be described with reference to FIG. First, in step 51 of FIG. 5, a power switch (not shown) of the input setting means 23 is turned on, and in step 52, an operation course suitable for washing is selected by the input setting means 23. When a start switch (not shown) is turned on, the washing operation is started, and the amount (cloth amount) of the laundry put into the washing and spin-drying tub 2 is detected.

As a method for detecting the amount of cloth, the motor 5 is driven to turn the stirring blade 7 right and left, and the inertial rotation speed when the motor 5 is turned off is used as the rotation speed detecting means 17.
When the inertia rotation speed is low, the amount of cloth is determined to be small, and when the inertia rotation speed is high, the amount of cloth is determined to be large.

On the basis of the result of the cloth amount detection, in step 54, water supply is started to the set water level PS1 corresponding to the cloth amount. The water supply valve 9 is turned on to supply water into the washing / dewatering tub 2. In step 55, the water supply is continued until the water level detecting means 10 detects the set water level PS1 determined by the cloth amount detection. When the set water level PS1 is detected by the water level detection means 10, the routine proceeds to step 56, where the water supply valve 9 is turned off and the water supply is terminated. After the water supply is completed, after step 57,
The washing and dewatering tub 2 is rotationally driven to start the washing operation.

Before starting the washing operation, a set current value It determined by the operation course set in step 57 and the set water level PS1 supplied into the washing and dewatering tub 2 is determined. The set current value It is set to 2.7 A for the middle water level, 3.1 A for the low water level, and 3.3 A for the small water level, depending on the washing water level.
Also, according to the result of the cloth amount detection, the setting is changed to 2.7 A when the detected cloth amount is 4 kg or more and 2.2 A when the detected cloth amount is less than 4 kg, even at the same middle water level.

Next, an upper limit rotation speed Tt determined by the operation course set in step 58 and the set water level PS1 supplied into the washing and dewatering tub 2 is determined. Similarly to the set current value It, the upper limit rotational speed Tt is set at 160% according to the washing water level.
r / min, low water level 180 r / min, small water level 1
Settings such as 90 r / min are made. Also, according to the result of the cloth amount detection, the detected cloth amount is 4 kg even at the same middle water level.
160r / min for above, 1 for less than 4kg
The setting is changed to 70 r / min.

By controlling the motor current value to be constant (constant torque control) in the steps 57 and 58, the relationship between the amount of washing water, the amount of clothing, and the amount of circulating water is determined as shown in FIG. As shown in c).

As shown in FIG. 4C, by changing the set current value It according to the water level, the interval between the curves of the circulating water amount for each water level is narrowed, and the total circulating water amount is increased. This means improved washing performance. In the curve a indicating the characteristic of the middle water level, the amount of circulating water of 4 kg or more of clothing is increased by changing the set current value It when the amount of clothing is 4 kg. In this way, water can be sprinkled moderately into the washing and dewatering tub 2 irrespective of fluctuations in the water level and the amount of cloth.

Further, the upper limit rotation speed Tt is such that when the rotation control based on the set current value It is performed, the rotation is excessively increased due to a small amount of laundry or the like, and detergent bubbles are generated excessively. This is a value set in order to prevent the problem described above.

In the driving course for washing blankets and fashionable clothes, the detergents used are often different.
When operated with a normal circulating water flow rate, detergent foam may be formed too much. Therefore, the upper limit rotation speed Tt is set to 120 r / min.
To reduce the amount of circulating water and suppress foaming.

In step 59, the timer 1 for counting the total washing time is cleared, and in step 60,
The timer 2 for measuring the ON or OFF time when the motor 5 is turned on / off is cleared. And
After step 61, the driving of the motor 5 for the washing operation is started.

The outline of the washing operation at this time will now be described. FIG. 6 shows the time transition of the number of rotations of the washing and dewatering tub 2 and the motor current value during the washing operation. Until the motor current value reaches the set current value It, the motor current is increased and the output torque of the motor 5 is increased, thereby increasing the rotation speed of the washing and spin-drying tub 2.

Then, control is performed so that the motor current value converges on the set current value It, and the motor 5 is turned on for a time t ₁ .
At this time, the rotation speed of the motor 5 is also a predetermined value (for example, 130
r / min). Then during the time t _2, the motor 5
Is turned off, and the washing and dewatering tub 2 is stopped. Then, the motor 5 is turned on again to rotate the washing / dewatering tub 2.
This operation is repeated until the total washing time tsen elapses.

As described above, the motor 5 is periodically turned on to rotate the washing / dewatering tub 2 to circulate the washing water to remove dirt from the clothes. The reason why the motor 5 is turned on / off periodically is that there is a problem of a rise in the temperature of the motor 5 and that if the motor 5 is turned on continuously, foaming by the detergent increases.

The description will be continued with reference to the flowchart of FIG. In step 61, start control for driving the motor 5 is performed. The start control method is as follows.
Is turned on and the inverter 1
4, the conduction ratio of the switching element 14 is increased, and the torque of the motor 5 is increased. In this manner, rotation can be started regardless of the amount of clothes in the washing and dewatering tub 2.

After starting, steps 62 to 7
In step 1, the duty ratio of the switching elements 14a to 14f of the inverter 14 is controlled by the motor current value detected by the current detecting means 18 and the rotation speed detected by the rotational speed detecting means 17, and feedback control is performed by the current value to obtain a constant torque. Thus, the washing and dewatering tub 2 is controlled to rotate.

The specific feedback control based on the current value in steps 62 to 71 is as follows. In step 63, it is detected whether a signal from the rotation speed detecting means 17 has been input. If a signal is detected, the process proceeds to step 64. In step 64, the current detecting means 1
8, the current value Im flowing to the motor 5 at this time is detected. Since the relationship between the current value and the motor torque is in a proportional relationship, the torque value applied to the motor 5 at this time can be estimated.

Next, at step 65, when the signal was inputted from the previous rotation speed detecting means 17, the current detecting means 18
Current value Imn-1 detected this time and current value Im detected this time
Is calculated (= Im-Imn-1). In step 66, the difference (deviation Ie) between the set current value It and the current value Im is calculated. In step 67, the current switching elements 14a to 14a are determined based on the deviation Ie and the variation ΔIm.
An operation amount ΔPI to be operated is calculated from the current-carrying ratio of f. That is, feedback based on the current value and feedback control to keep the motor torque constant are performed.

At step 68, the current rotational speed Tp is obtained from the signal detected by the rotational speed detecting means 17, and at step 69
Then, it is determined whether the current rotational speed Tp is equal to or higher than the upper limit rotational speed Tt. If the rotational speed is equal to or less than the upper limit rotational speed Tt, the process directly proceeds to step 71, and the operation amount Δ determined in step 67
A new conduction ratio Pa is set by P1.

If the current rotational speed Tp is equal to or higher than the upper limit rotational speed Tt, it is necessary to reduce the rotational speed. As a control method for determining the operation amount, proportional control in which the operation amount is increased as the difference between the upper limit rotation speed Tt and the current rotation speed Tp is larger is effective. Based on this control, the operation amount ΔP2 is determined, and the process proceeds to step 71, where a new conduction ratio Pa is set based on the operation amount ΔP1 and the operation amount ΔP22.

The above control is repeated at step 62 to determine the ON time of the motor and repeat until the time t _{1 has} elapsed.
The washing and dewatering tub 2 is controlled so as to rotate at a constant torque, the washing water is circulated, and a washing operation for removing dirt on clothes is performed.

If this operation is performed continuously, the winding temperature of the motor 5 rises too much, so that it is necessary to insert a motor-off period for a certain period of time. Therefore, the process proceeds to step 72, in step 72 to step 74 to turn off only the motor 5 period of time t _2. The periodic intermittent operation of turning on the motor at time t ₁ and turning off the motor at time t _{2 is} repeated until the washing time tsen elapses. When the time tsen elapses, the washing process ends, and the process proceeds to the next process.

[0061]

As described above, according to the first aspect of the present invention, the washing and dewatering tub provided rotatably in the outer tub, the driving means for driving the washing and dewatering tub, A water level detecting means for detecting a water level of the washing and dewatering tub; and a control means for controlling the stroke by controlling the driving means, wherein the control means rotates the washing and dewatering tub to wash the outer tub with the washing and dewatering tub. Since the washing and dewatering tub has a washing step of sprinkling washing water into the washing and dewatering tub, and the current value of the driving means is controlled to be substantially constant according to the water level of the washing and dewatering tub, By detecting the amount of washing water and the current flowing through the driving means, the current of the driving means is controlled to be constant according to the amount of washing water so that a constant torque is applied to the washing and dewatering tub, and Even if there is a difference in the amount of washing and the amount of washing water, almost the same amount of It can be a to. In addition, even when the amount of clothing is too large, a certain amount of current can be prevented from flowing through the driving means, so that the permanent magnet provided on the rotor in the motor constituting the driving means is prevented from being demagnetized. be able to.

According to the second aspect of the present invention, there is provided a cloth amount detecting means for detecting the amount of clothes in the washing and dewatering tub,
The control means is configured to control the current value of the driving means to be substantially constant by the output of the cloth amount detection means, so that even if there is a difference in the amount of clothes in the washing and dewatering tub, the control can be performed with higher accuracy. In addition, the amount of water sprayed into the washing and dewatering tub can be kept constant, and the washing performance can be improved.

According to the third aspect of the present invention, there is provided an inverter comprising a switching element for supplying power to the driving means, and a current detecting means for detecting a current value corresponding to a current flowing through the driving means, The control unit compares the output value of the current detection unit with the current set value, controls the conduction ratio of the switching element to control the number of revolutions of the drive unit. Since the driving means can be controlled, the torque of the motor (driving means) can be stably and accurately fixed to give a constant torque to the washing and dewatering tub, and the amount of clothes and the amount of washing water in the washing and dewatering tub can be provided. Even if there is a difference, it is possible to sprinkle the same amount of water required for cleaning clothes in the washing and dewatering tub. Thereby, it is possible to remove the stains on the clothes while suppressing the occurrence of foaming due to the detergent. In addition, since a current value exceeding a certain value can be prevented from flowing through the motor, it is possible to prevent a permanent magnet provided on a rotor in the motor constituting the motor from being demagnetized and the motor from being damaged.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a washing machine according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a part of the washing machine in a block form;

FIG. 3 is an operation timing chart of the inverter of the washing machine.

4A is a characteristic diagram showing the relationship between the amount of clothing and the amount of circulating water when the current flowing through the motor is constant. FIG. 4B is a characteristic diagram showing the relationship between the amount of clothing and the amount of circulating water when the current flowing through the motor is increased. c) Relational characteristic diagram between the amount of clothes and the amount of circulating water in the washing machine according to the embodiment of the present invention.

FIG. 5 is an operation flowchart of a main part of the washing machine.

FIG. 6 is an operation timing chart of main parts of the washing machine.

FIG. 7 is a longitudinal sectional view of a conventional washing machine.

FIG. 8 is a block circuit diagram of the washing machine.

[Description of Signs] 1 outer tub 2 washing and dewatering tub 5 motor (drive means) 10 water level detection means 16 control means

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Tadashi Inuzuka 1006 Kadoma Kadoma, Osaka Pref.Matsushita Electric Industrial Co., Ltd. F term (reference) 3B155 AA01 BB08 CB06 HC05 HC07 KA02 KA19 KB08 LB17 LC12 MA01 MA05 MA06 MA09

Claims (3)

[Claims] 1. A washing and dewatering tub rotatably provided in an outer tub, a driving means for driving the washing and dewatering tub, a water level detecting means for detecting a water level of the washing and dewatering tub, and the driving means Control means for controlling the stroke and controlling the stroke, the control means rotating the washing and dewatering tub to spray the washing water into the washing and dewatering tub from between the outer tub and the washing and dewatering tub. A washing machine having a washing step, wherein a current value of the driving means is controlled to be substantially constant according to a water level of the washing and dewatering tub. 2. A laundry amount detecting means for detecting the amount of clothes in the washing and dewatering tub, wherein the control means controls the current value of the driving means to be substantially constant by the output of the clothing amount detecting means. The washing machine according to claim 1. 3. An inverter comprising a switching element for supplying power to the driving means, and a current detecting means for detecting a current value corresponding to a current flowing through the driving means, wherein the control means outputs the current of the current detecting means. 3. The method according to claim 1, wherein the control unit controls the rotation speed of the driving unit by comparing a current setting value with a current setting value and controlling a conduction ratio of the switching element.
The washing machine as described.