JP2000024366A - Washing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a washing performance by decreasing damage to clothes at the time of washing and reduce a washing period of time by efficiently providing a maximum torque of a motor so that a predetermined number of revolution of a washing tank can be rapidly reached. SOLUTION: A motor 4 is driven by the output of an inverter circuit 23 for switching input direct-current voltage to drive a pulsator or a washing tank. A control means 18 controls a washing, rinsing, and dehydrating steps and controls the inverter circuit 23, whereby after feeding water into the water tank, the washing tank is rotated by the motor 4 to force the water in the water tank onto the inner periphery thereof, bringing the water into contact with a rib of a receiving cover so that the water is circulated within the water tank, wherein a switching state of the circuit 23 is controlled so that outputs of a current sensing means 21 for sensing the electric current of the motor 4 is kept at a predetermined value or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a washing machine in which a pulsator or a washing tub is driven by a motor driven by an inverter circuit.

[0002]

2. Description of the Related Art Conventionally, a washing machine has been demanded to have good dirt removal and a short washing time, and further, to have little damage to clothes.

In a conventional washing machine, an induction motor is generally used to rotate a pulsator or a washing tub, and the pulsator is finely turned over, or a net is used at the time of washing. I was less.

[0004] However, it is difficult to arbitrarily adjust the rotation speed of the induction motor, so that it is difficult to optimally wash laundry of various qualities and quantities. Therefore,
A washing machine has been proposed in which a DC brushless motor is driven by an inverter circuit and the number of revolutions of a pulsator can be freely changed.

In such a washing machine, the rotation of the motor is controlled to a predetermined target rotation speed during washing. That is,
A circuit that generates a pulse according to the rotation of the motor to control the rotation speed is provided, and the pulse rotation time is measured to determine the rotation speed of the motor. In this case, a motor drive control circuit is controlled to increase or decrease the rotation speed so that the motor rotates at a target rotation speed.

In this way, the rotation speed of the pulsator driven by the motor is adjusted. The pulsator was rotated slowly to prevent delicate clothes from being damaged, and the pulsator was rotated quickly to create a strong current and wash stubborn dirt.

[0007]

However, in such a conventional washing machine, since the pulsator is rotated and the laundry is washed with a water current that moves while stirring, there is a problem that the laundry is easily entangled. In addition, there is a problem that washing time is extended when the pulsator is slowly rotated for washing.

Further, when a motor for rotating a pulsator or a washing tub is constituted by a DC brushless motor, and a large current is applied to the winding of the DC brushless motor, an excessively reverse magnetic field is applied to a permanent magnet constituting the rotor. However, since the permanent magnet is demagnetized and the motor does not operate, it is necessary to slowly drive the motor at a low torque at the start of driving, it takes time to start rotation, the cleaning performance is reduced, and the washing time is reduced. There was a problem of becoming long.

The present invention has been made to solve the above-mentioned problems, and suppresses damage to clothes during washing, improves washing performance, and drives the motor while controlling the current of the motor to reduce the maximum torque of the motor. It is an object of the present invention to make the washing tub quickly reach a predetermined number of revolutions to shorten the washing time.

[0010]

According to the present invention, in order to achieve the above object, a washing tub having a pulsator disposed at the bottom is contained in a water tub, and a receiving cover provided with a rib for controlling the flow of water is provided in the water tub. The pulsator or the washing tub is driven by driving the motor with the output of the inverter circuit that switches the input DC voltage by covering the upper part. The control means controls processes such as washing, rinsing, and dehydration, and also controls an inverter circuit.After supplying water to the water tub, the washing tub is rotated by a motor, and water in the water tub is pressed around the water tub, and ribs of the receiving cover are provided. And a step of circulating in the washing tub in such a way that the switching state of the inverter circuit is controlled so that the output of the current detecting means for detecting the current of the motor becomes equal to or less than a predetermined value in this step. It is.

[0011] Thereby, the damage of the clothes at the time of washing is suppressed,
The cleaning performance can be improved, and the maximum torque of the motor can be efficiently obtained by driving the motor with the inverter circuit while controlling the current flowing through the motor.
The washing tub can quickly reach a predetermined number of revolutions, and the washing time can be reduced.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is characterized in that a water tub containing a washing tub having a pulsator disposed at the bottom is included, a receiving cover covering an upper part of the water tub, and a receiving cover provided on the receiving cover. A rib for controlling the flow of water, a motor for driving the pulsator or the washing tub, an inverter circuit for switching an input DC voltage to obtain an output for driving the motor, and current detecting means for detecting a current of the motor Washing, rinsing, comprising control means for controlling the inverter circuit by controlling processes such as dehydration, the control means, after supplying water to the water tub, the washing tub is rotated by the motor, the inside of the water tub A step of circulating water in the washing tub by pressing water around the water tub and hitting the ribs of the receiving cover, and in this step, the output of the current detecting means becomes equal to or less than a predetermined value. In the process of rotating the washing tub to press the water in the water tub around the water tub and circulating the water in the washing tub, the clothes are rubbed with a pulsator. When washing with the same amount of detergent, there is almost no damage to the clothes at the time of washing, and it can be washed with little water, because there is no damage and the clothes are pressed against the wall of the washing tub and the water is passed through the clothes and washed. Increases the detergent concentration of the washing liquid,
The washing rate of clothes can be improved. At this time, in order to rotate the washing tub filled with water, a high motor torque is required, but since the motor is driven by the inverter circuit while controlling the current flowing through the motor, the maximum torque of the motor can be efficiently obtained. This allows the washing tub to quickly reach a predetermined number of revolutions. For this reason, the washing time can be reduced. Furthermore, since current is detected and controlled, overcurrent does not flow to the motor, so even if the motor is configured with a DC brushless motor, it is possible to avoid failure due to demagnetization of the permanent magnets that make up the rotor and heat generation of the motor. can do.

According to a second aspect of the present invention, in accordance with the first aspect of the present invention, there is provided a DC brushless motor for rotating and driving a washing tub. The motor efficiency is higher than that of an induction motor, and the motor current is higher. The motor is driven by the inverter circuit while detecting the torque, so that a high torque can be obtained without demagnetizing the magnet of the DC brushless motor and impairing the function of the motor.

According to a third aspect of the present invention, in the first or second aspect of the present invention, an imbalance detection lever is provided near a side surface of the washing tub, and the control means is configured to rotate the washing tub when the washing tub is rotating. When the washing tub comes into contact with the unbalance detection lever, the process of stopping the rotation of the washing tub, inverting the pulsator at a predetermined cycle, and then rotating the washing tub to circulate water is restarted. If an imbalance is detected, the predetermined value of the output of the current detection means is reset to a small value, and the washing tub at the start of rotation of the washing tub shakes greatly and the washing machine abnormally vibrates. In addition, even when an imbalance occurs, the imbalance can be automatically eliminated and the washing process can be continued, so that the possibility of the process being stopped halfway can be reduced.

According to a fourth aspect of the present invention, in the first or the second aspect of the present invention, there is provided a rotation speed detecting means for detecting a rotation speed of the motor, and the control means drives the motor, and thereafter supplies current to the motor. The amount of laundry in the washing tub is detected from the number of rotations of the motor during the inertial rotation when the motor is shut off, and the rotation of the washing tub in the process of rotating the washing tub and circulating water according to the amount of laundry is performed. The number is controlled, and substantially the same washing performance can be obtained regardless of the amount of laundry. Further, when the amount of laundry is small, washing can be performed in a short time, and unnecessary power consumption can be prevented because the rotation speed is controlled in accordance with the amount of laundry.

[0016] The invention according to claim 5 provides the above-mentioned claims 1 to
In the invention described in 4, the DC power supply section input to the inverter circuit is provided with a reactor and a step-up chopper type semiconductor switching element. Since the peak input current of the inverter circuit can be suppressed, the circuit power factor can be improved. Further, the size of the reactor can be reduced, and the cost can be reduced. In addition, since distortion of the input current waveform is suppressed, other devices are not affected by noise.

[0017]

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

(Embodiment 1) As shown in FIG.
Has a pulsator 2 rotatably disposed at the center bottom. The water tub 3 includes the washing tub 1, and a motor 4, a drain valve 5, a washing / dewatering switching mechanism 6, and the like are provided at an outer bottom portion of the water tub 3. It is suspended from the upper corner of the frame 9. An upper cover 10 is provided above the outer frame 9, and a water supply valve 11, a control device 12, and the like are provided. A receiving cover 14 provided with ribs 13 and an inner lid 15 are provided around the upper portion of the washing tub 1. Further, an unbalance detection lever 16 is provided on the outer peripheral side surface of the washing tub 1.

The clutch switching mechanism 17 switches so as to transmit the driving force of the motor 4 to the pulsator 2 or the washing tub 1.

The control device 12 is constructed as shown in FIG. 1. The control means 18 receives a water supply valve 11 and a drain valve via a switching means 20 in response to an input from an operation means 19 such as a key switch. 5. Clutch switching mechanism 17
Controls the operation of the current detection means 21, the Hall IC 2
The operation of the motor 4 is controlled via the inverter circuit 23 in accordance with the input of the rotation speed detecting means 22 composed of 2a, 22b, 22c, and the processes such as washing, rinsing, and dehydrating are controlled.

The rotation number detecting means 22 detects the rotation number of the washing tub 1 by detecting the rotation number of the motor 4, and the water level detecting means 24 detects the water level in the washing tub 1. The respective outputs are input to the control means 18. The display means 25 displays the input state and a series of progress states. 26 is a power switch, and 27 is a commercial power supply. The commercial power supply 27 is converted into a direct current by a rectifying / smoothing circuit 28.

The current detecting means 21 is configured as shown in FIG. 3, and detects by providing a shunt resistor 30 in the power supply line 29 and measuring the voltage across the shunt resistor 30. A filter circuit 31 is provided at the output of the voltage for noise suppression at the time of semiconductor switching or the like, and the output detects the motor current.

FIG. 6 is a main block diagram of the control means 18 when the motor 4 is driven in the process of rotating the washing tub 1 to press the water in the tub 3 around the tub 3 and circulating the water in the washing tub 1. It is a circuit diagram.

The current setting means 32 sets the limit value of the current of the motor 4. The current setting means 32 inputs the limit value to the comparator 33 together with the output of the current detecting means 21. Set. The output of the rotation speed setting means 34 is input to the comparator 35 together with the output of the rotation speed detection means 22, and the comparator 35 outputs a difference δN in the rotation speed.

The rotational speed change amount detecting means 36 detects the rotational speed change amount dN / dt from the output of the rotational speed detecting means 22, and the output dN / d of the rotational speed change amount detecting means 36.
t and the output δN of the comparator 35 are input to the fuzzy control means 37, and the output thereof is used to control the inverter circuit 23 via the inverter drive circuit 38.

When information on a predetermined washing course is given to the control means 18 by the operation means 19, a motor current limit value is set. When the motor rotation speed is lower than a predetermined target rotation speed by the rotation speed detection unit 22,
The operating state of the motor is detected by the current detecting means 21.
When the motor speed N is different from the target speed, the switching operation of the inverter drive circuit 38 is changed.

At this time, the fuzzy control means 37 uses the fuzzy control means 37 based on the difference δN between the rotation speed of the motor 4 detected by the rotation speed detection means 22 and the set rotation speed set by the rotation speed setting means 34 and the rotation speed change amount dN / dt. By changing the drive duty ratio of the switching element of the inverter drive circuit 38 by logic, the rotation speed of the motor is controlled.

At this time, the current detecting means 21 prevents the motor current from exceeding the set value. That is, when the motor current is larger than the set value, the motor current is suppressed by lowering the motor rotation speed set value.

The operation of the above configuration will be described with reference to FIGS. When the operation is started in step 100 of FIG. 5, the control means 18 controls the driving force of the motor 4 by the clutch switching mechanism 17 in step 101.
From the washing tub 1. Then, in step 102, the water supply valve 11 is driven to supply water to a predetermined water level, and the switching element of the inverter circuit 23 is controlled to rotate the washing tub 1.

When the rotation of the washing tub 1 is started, a high torque is required to increase the acceleration. However, when a large current is applied to the motor 4, the motor windings are overheated, and as described later, when the motor is configured by a DC brushless motor, the rotor is configured by a strong magnetic field generated by the large current. Permanent magnets can be demagnetized.

Therefore, at step 103, it is determined whether the current of the motor 4 detected by the current detecting means 21 is equal to or less than a predetermined limit value. If the current value exceeds the limit value, the drive duty ratio is reduced at step 104. And return to step 103. At step 105, it is determined whether or not the rotation speed of the motor 4 detected by the rotation speed detecting means 22 is higher than a predetermined value. If the rotation speed is higher than the predetermined value, the drive duty ratio is increased at step 106 and the process returns to step 103. .

At the beginning of rotation, the drive duty ratio is small,
The rotation speed is increased while being detected until the rotation speed reaches a predetermined rotation speed. At this time, if the motor current is detected and exceeds the limit value, as described above, the drive duty ratio is reduced and control is performed so that an excessive current does not flow.

At this time, when the washing tub 1 is rotated, as shown in FIG. 6, the water in the water tub 3 is rotated by the rotation of the washing tub 1, and the water level is centrifuged from the state shown in FIG. The state shown in FIG. As the number of revolutions is gradually increased, the water level reaches the receiving cover 14 as shown in FIG. 5 (c), the water hits the rib 13 and flows down toward the center of the washing tub 1, and the laundry is passed through. The water circulates through the holes provided in the wall surface.

Next, in steps 107 and 108 in FIG. 5, the speed of the motor 4 is increased until it reaches N1.
When the time t1 elapses at 09, steps 110 and 11
At 1, the motor 4 is decelerated until the number of revolutions becomes N2, and after the time t2 elapses at step 112, the process is repeated at step 113 until the number of repetitions reaches N3.

Therefore, the state shown in FIG. 6 (b) and the state shown in FIG. 6 (c) are alternately repeated to wash the clothes. When the centrifugal washing for a predetermined time is completed, the process proceeds to the next step.

FIG. 7 shows the torque and speed characteristics of the motor 4 and a load curve. As described above, in the torque-rotational speed characteristic curve, the torque becomes substantially constant from the point A by controlling the current of the motor 4 to a predetermined limit value or less. An example of a load curve in the process of rotating the washing tub 1 to press the water in the water tub 3 around the water tub 3 and circulating the water in the washing tub 1 is shown by a solid arrow a. During the first few milliseconds when the rotation of the washing tub 1 starts, a so-called soft start in which the on-time duty ratio of the switching element of the inverter circuit 23 is reduced is performed.

Thereafter, the drive duty ratio of the inverter drive circuit 38 is increased until the set number of revolutions is reached. At this time, the motor current value is detected by the current detecting means 21, the duty ratio is increased or decreased so as not to exceed the limit value, the current value, that is, the torque is limited, and finally the motor reaches a predetermined rotation speed.

When the motor current is not limited, the load curve changes according to the amount of the laundry, and becomes a load curve as shown by broken lines b and c in FIG. When the amount of the laundry is large (broken line b), there is a high possibility that an excessive current flows, and when the amount of the laundry is small (dashed line c), the rising of the rotation is delayed. That is, the control is susceptible to a change in the amount of laundry.

As described above, in this embodiment, since the torque is limited by limiting the motor current, optimal motor torque control can be performed regardless of the amount of the laundry, and the rotation of the washing tub 1 can be controlled. It has the advantages of quick startup and shorter washing time. Further, since an excessive torque is not generated, there is an advantage that a durable life of a mechanical portion around a motor of the washing machine is extended.

It should be noted that the rotation speed detecting means 22 is a Hall IC.
Although an example in which the rotor position detection and the rotation speed detection of the motor 4 are used by using three motors is shown, a rotary encoder is used, the rotation speed is detected by two Hall ICs, and the pulse of the induced voltage of the motor coil is counted. Alternatively, the rotation speed may be detected.

Further, by rotating the washing tub 1 while supplying water from the water supply valve 11 for supplying water to the water tub 3, the washing time can be reduced.

(Embodiment 2) As shown in FIG.
9 uses a DC brushless motor having three-phase windings. The detection of the rotational position of the rotor and the detection of the number of rotations of the motor 39 are performed using the Hall ICs 40a, 40b, and 40c. The inverter circuit 41 drives the motor 39 by alternately turning on and off the six switching elements to form a three-phase AC power supply.

FIG. 9 shows an example of the on / off timing of the semiconductor switching elements 41a to 41f of the inverter circuit 41. The torque control of the motor 39 is performed by the switching element 41.
a, 41c, and 41e are switched at a high frequency to control the effective voltage applied to each phase of the motor 39. That is, by reducing the on / off duty ratio of the switching elements 41a, 41c and 41e, the motor 3
9 is performed. Other configurations are the same as those in the first embodiment.

In the above configuration, since a DC brushless motor having high efficiency and a large starting torque is used as the motor 39, the motor 39 that obtains a high torque for rotating the washing tub 1 with water in the water tub 3 is made compact. Configurable. Further, since the motor 39 has no brush, there is an advantage that the life of the motor is long and the noise is small. Therefore, a washing machine with high reliability and quiet sound can be realized.

(Embodiment 3) The unbalance detection lever 16 shown in FIG. 2 detects a case in which the laundry is offset and the laundry tub 1 shakes greatly when the laundry tub 1 rotates. In the process of rotating the washing tub 1 to press the water in the water tub 3 around the water tub 3 and circulating the water in the washing tub 1, when the rotation speed of the washing tub 1 is raised to a predetermined value with a large torque in a short time, Balance may occur and large vibrations may occur. When the washing tub 1 swings and comes into contact with the unbalance detection lever 16, a switch (not shown) interlocked with the lever is turned on to determine the imbalance state.

When the imbalance is detected, the cloth is loosened by reversing the pulsator 2 in small increments to eliminate the imbalance. Thereafter, the washing tub 1 is rotated again. If imbalance continues at this time,
By reducing the starting torque and slowing the startup time, the probability of occurrence of imbalance is reduced.

This process is performed until the imbalance is eliminated.
Repeat a predetermined number of times. If the imbalance has not been resolved after a predetermined number of times, the process is stopped.

As described above, according to this embodiment, it is possible to prevent the washing tub 1 from shaking at the start of rotation of the washing tub 1 and abnormally oscillating. In addition, even when an imbalance occurs, it is possible to automatically eliminate the imbalance and continue the washing process, thereby reducing the possibility that the process is interrupted halfway.

(Embodiment 4) The control means 18 shown in FIG.
At the start of washing, the motor 4 is driven so as to reach a predetermined rotation speed. After that, the power is cut off and the motor 4
Is detected by the number of pulses of the Hall IC 22. The amount of the laundry in the washing tub 1 is detected based on the magnitude of the rotation angle.

When the amount of laundry is large, it is necessary to increase the amount of circulating water in order to obtain the washing performance. Therefore, the control means 18 achieves the washing performance by increasing the rotation speed of the washing tub 1 according to the amount of the laundry. When the load is small, the time of each step is set short.

As described above, in this embodiment, even if the amount of laundry changes, the same washing performance can be obtained regardless of the amount of laundry. Also, if the amount of laundry is small,
Washing can be performed in a short time, and unnecessary power consumption can be prevented because the number of rotations is controlled according to the amount of laundry.

Embodiment 5 As shown in FIG. 10, the DC power supply of the inverter circuit 23 is
, A reactor 43, a step-up chopper type semiconductor switching element 44, and an input capacitor 45.
Other configurations are the same as those in the first embodiment.

In the above configuration, in the process of rotating the washing tub 1 to press the water in the water tub 3 around the water tub 3 and circulating the water in the washing tub 1, the washing tub 1 is rotated after water is supplied. Requires torque. At this time,
The peak of the input current of the converter circuit section 42 increases, the circuit power factor decreases, and the input current waveform distortion increases.

In the present embodiment, the voltage of the input capacitor 45 is controlled by turning on and off the boosting chopper type semiconductor switching element 44 to boost the power supply voltage using the electromotive force generated in the reactor 43. Therefore, the current at the peak of the power supply voltage can be suppressed.

As a result, the circuit power factor can be improved, the reactor 43 can be small, and the power supply distortion can be reduced. In addition, since distortion of the input current waveform is suppressed, other devices are not affected by noise.

In each of the above embodiments, one current detecting means is connected to the input side of the inverter circuit.
At least two phase currents of the phase motor may be detected. The other one-phase current value is obtained by combining these two phases. With such a configuration, there is an advantage that it is possible to immediately detect when the lead wire of the motor is broken.

[0057]

As described above, according to the first aspect of the present invention, a water tub containing a washing tub having a pulsator disposed at the bottom, a receiving cover for covering an upper periphery of the water tub, A rib for controlling the flow of water provided on the receiving cover, and a motor for driving the pulsator or the washing tub,
An inverter circuit that obtains an output for driving the motor by switching an input DC voltage; a current detection unit that detects a current of the motor; and a control unit that controls processes such as washing, rinsing, and dehydration to control the inverter circuit. With
The control means includes a step of, after supplying water to the water tub, rotating the washing tub by the motor, pressing water in the water tub around the water tub, and circulating the water in the washing tub by hitting the rib of the receiving cover. Then, in this step, since the switching state of the inverter circuit is controlled so that the output of the current detecting means is equal to or less than a predetermined value, after supplying water, the washing tub is rotated and the water in the water tub is rotated. Is pressed against the periphery of the water tank by centrifugal force, and has a process of circulating by applying water to the ribs of the receiving cover. Therefore, optimal motor torque control can be performed regardless of the amount of laundry. The spinning speed of the washing tub is quick, and the washing time can be reduced.

According to the second aspect of the present invention, since the DC brushless motor for rotating and driving the washing tub is provided, it is possible to compactly construct a motor for obtaining a high torque for rotating the washing tub with water in the tub. It is. Further, since there is no brush for the motor, there is an advantage that the life of the motor is long and the noise is small. Therefore, a washing machine with high reliability and quiet sound can be realized. Since the number of rotations is controlled by detecting the current, it is possible to prevent the magnet of the motor from being demagnetized by flowing an overcurrent.

According to the third aspect of the present invention, an unbalance detection lever is provided near a side surface of the washing tub, and the control means detects the unbalance when the washing tub is rotating. When contacting the lever, the rotation of the washing tub is stopped, the pulsator is inverted at a predetermined cycle, and then the washing tub is rotated to restart the process of circulating water,
When the imbalance is continuously detected, the output predetermined value of the current detecting means is reset to a small value, so that the washing tub at the start of rotation of the washing tub shakes greatly and the washing machine abnormally vibrates. In addition, even when an imbalance occurs, the imbalance can be automatically eliminated and the washing process can be continued, so that the possibility of the process being stopped halfway can be reduced.

According to the fourth aspect of the present invention, there is provided a rotation speed detecting means for detecting the rotation speed of the motor, wherein the control means drives the motor and controls the time of the inertia rotation when the energization is cut off. Because the amount of laundry in the washing tub is detected from the number of rotations of the motor, the number of rotations of the washing tub in the process of rotating the washing tub and circulating water is controlled according to the amount of laundry. Approximately the same washing performance can be obtained regardless of the amount of laundry. Further, when the amount of laundry is small, washing can be performed in a short time, and unnecessary power consumption can be prevented because the rotation speed is controlled in accordance with the amount of laundry.

According to the fifth aspect of the present invention, since the reactor and the boost chopper type semiconductor switching element are provided in the DC power supply section input to the inverter circuit, the peak input current of the inverter circuit can be suppressed. The power factor can be improved, the reactor can be downsized, and the cost can be reduced. In addition, since distortion of the input current waveform is suppressed, other devices are not affected by noise.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram of a washing machine according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the washing machine.

FIG. 3 is a circuit diagram of a power detection unit of the washing machine.

FIG. 4 is a main part block circuit diagram of control means of the washing machine.

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

FIG. 6 (a) is a sectional view of a main part of the washing machine in a state where a washing tub is stopped; (b) is a sectional view of a main part of the washing machine in a state where a washing tub is rotating at a low speed; Sectional view of the main part of the washing machine with the washing tub rotating at high speed

FIG. 7 is a torque-rotation speed load characteristic diagram of a motor of the washing machine.

FIG. 8 is a partially block circuit diagram of a washing machine according to a second embodiment of the present invention.

FIG. 9 is a timing chart of an inverter circuit of the washing machine.

FIG. 10 is a circuit diagram of a washing machine according to a fifth embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 washing tub 2 pulsator 3 water tub 4 motor 13 rib 14 receiving cover 18 control means 21 current detection means 23 inverter circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Katsuyuki Nagai 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Sadayuki Tamae 1006 Kadoma Kadoma Kadoma City Osaka Pref. Term (Reference) 3B155 AA10 BA09 BA16 BB08 BB15 BB16 CA05 CA16 CB06 EA12 GC06 HB10 HC06 KA02 KA34 KA35 KB03 KB08 KB11 LB17 LB35 LC02 LC15 LC33 LC38 MA05

Claims (5)

[Claims] 1. A water tub containing a washing tub having a pulsator disposed at a bottom portion, a receiving cover covering an upper part of the water tub, a rib for controlling a flow of water provided on the receiving cover, the pulsator or the washing machine. A motor for driving the tank,
An inverter circuit that obtains an output for driving the motor by switching an input DC voltage; a current detection unit that detects a current of the motor; and a control unit that controls processes such as washing, rinsing, and dehydration to control the inverter circuit. With
The control means includes a step of, after supplying water to the water tub, rotating the washing tub by the motor, pressing water in the water tub around the water tub, and circulating the water in the washing tub by hitting the rib of the receiving cover. A washing machine configured to control a switching state of the inverter circuit so that an output of the current detection unit is equal to or less than a predetermined value in this step. 2. The washing machine according to claim 1, further comprising a DC brushless motor that rotationally drives the washing tub. 3. An unbalance detection lever is provided near the side surface of the washing tub, and the control means rotates the washing tub when the washing tub comes into contact with the unbalance detection lever while the washing tub is rotating. Is stopped, the pulsator is inverted at a predetermined cycle, and then the washing tub is rotated to restart the process of circulating water.If unbalance is continuously detected, the output predetermined value of the current detecting means is reset to a small value. The washing machine according to claim 1 or 2, wherein the washing is performed. 4. A rotating speed detecting means for detecting a rotating speed of the motor, wherein the control means drives the motor, and then, based on the rotating speed of the motor during the inertial rotation when the power is cut off, the washing in the washing tub. 3. The washing machine according to claim 1, wherein an amount of the laundry is detected, and a rotation speed of the laundry tub in a process of rotating the laundry tub and circulating water is controlled according to the amount of the laundry. 5. The washing machine according to claim 1, wherein a reactor and a step-up chopper type semiconductor switching element are provided in a DC power supply section input to the inverter circuit.