JP2009006081A - Washing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance washing performance by controlling a discharging pressure when discharging water from an outlet of a circulating water spray device into a drum in a drum-type washing machine equipped with the circulating water spray device using a circulating pump. <P>SOLUTION: In a washing machine equipped with the circulating water spray device for circulating water in a water tank by sucking the water through a circulating water passage by a pumping action of the circulating pump and by discharging the water from the outlet into the inside of the drum and further into the water tank, a pump motor comprising a brushless motor is used for a driving source of the circulating pump to vary a rotation speed of the pump motor in the washing process and the rinsing process. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a washing machine provided with a circulating watering device that circulates water in a water tank by sucking it through a circulating water channel by a pumping action of a circulation pump, and discharging the water from a discharge port into the water tank.

  Conventionally, for example, in a drum type washing machine, for the purpose of improving washing performance and saving water, a circulation watering device having a circulation pump is provided, and the circulation pump of the circulation watering device is driven when the laundry is rinsed or rinsed. Thus, a configuration is considered in which water in the water tank is sucked through a circulation water channel and discharged from the discharge port into the water tank (inside the drum) for circulation. At this time, water discharged from the discharge port into the water tub is applied to the laundry accommodated in the drum. Moreover, in this kind of thing, the lint capture part is provided in the circulation channel, and the lint (waste thread) which comes out of the laundry is captured in the lint capture part. A pump motor that is a drive source of the circulation pump is generally a take-off type motor or a condenser motor.

In such a configuration, by turning on / off the circulation pump (pump motor) of the circulation watering device, the injection direction (injection degree) of water discharged from the discharge port into the drum is changed, whereby the drum There has been proposed a method in which water is poured over a wide area (see, for example, Patent Document 1).
Also, in a so-called vertical washing machine in which the axis of the rotating tub (inner tub) in the water tub (outer tub) is oriented vertically, a pump that is equipped with a circulating watering device similar to the above and is a drive source of the circulation pump A DC brushless motor is used as the motor, and when the circulation pump is stopped, the rotation speed (rotational speed) of the pump motor is decreased stepwise to prevent the lint captured by the lint capture unit from flowing backward. The thing which made it do is proposed (for example, refer patent document 2).
Japanese Patent Laid-Open No. 9-182887 JP 2007-29205 A

In the thing of patent document 1, it is possible to change the injection direction (injection degree) of the water discharged from a discharge port into a drum to a perspective (large and small) by turning on / off the circulation pump of a circulation sprinkler. However, the discharge pressure of water discharged from the discharge port into the drum cannot be arbitrarily adjusted.
On the other hand, Patent Document 2 describes that the lint captured by the lint capturing unit is prevented from flowing backward by gradually decreasing the rotational speed of the pump motor when the circulating pump is stopped. However, the control of changing the discharge pressure of the water discharged from the discharge port into the rotary tank (inner tank) during the water circulation operation by the circulation pump is not performed.

  The present invention has been made in view of the above circumstances, and its purpose is to discharge water from the outlet of the circulating watering device into the drum in a drum-type washing machine equipped with a circulating watering device using a circulation pump. It is an object of the present invention to provide a washing machine that can control the discharge pressure at the time of cleaning and further improve the cleaning performance.

  In order to achieve the above-described object, the present invention has a water tank capable of storing water and a hole capable of passing water, and is rotatably disposed in the water tank. In the washing machine, comprising: a rotating drum; and a circulation watering device that circulates the water in the water tank through the circulation water path by a pumping action of a circulation pump, and discharges the water from the discharge port into the water tank. The pump uses a pump motor composed of a brushless motor as a drive source, and includes a control means for controlling the rotation speed of the pump motor, and the control means changes the rotation speed of the pump motor within one stroke during the washing operation. It is characterized by making it.

  According to the present invention, since the pump motor composed of the brushless motor is used as the drive source of the circulation pump, the rotational speed of the pump motor can be easily controlled. And the discharge pressure of the water discharged into the drum from the discharge port of the circulation sprinkler can be easily changed by changing the rotational speed of the pump motor within one stroke during the washing operation. By changing the discharge pressure of water discharged from the discharge port, it is possible to change the water discharge direction and discharge range, and it is possible to pour water over the entire laundry in the drum, which improves the washing performance of the laundry. This can be further improved.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
First, in FIGS. 1 and 2, the outer box 1 has a rectangular box shape, and a base plate 3 having legs 2 at the bottom is provided. A laundry doorway 4 is formed at the front portion (left side in FIG. 1) of the outer box 1, and a door 5 for opening and closing the laundry doorway 4 is rotatably provided via a hinge (not shown). .

  In the outer case 1, a water tank 6 capable of storing water is disposed via an elastic support mechanism 7. The water tank 6 has a bottomed cylindrical shape whose front surface is open and whose rear surface is closed, and is arranged so that the axial direction is inclined upwardly from the horizontal direction. An annular water tank cover 8 is attached to the front of the water tank 6. This water tank cover 8 has a projecting part 8a projecting in the center direction from the peripheral wall part of the water tank 6, and a short cylindrical projecting part 8b projecting forward from the tip of the projecting part 8a. An inner peripheral portion of the portion 8b is an opening 9. A bellows 10 is provided between the front end of the protrusion 8b and the laundry entrance / exit 4, and the bellows 10 connect the opening 9 of the water tub 6 and the laundry entrance / exit 4 in a watertight and airtight manner. ing.

  A drum 11 is rotatably disposed in the water tank 6. Similarly to the water tank 6, the drum 11 has a bottomed cylindrical shape whose front surface is open and whose rear surface is closed, and is arranged so that the axial direction is inclined upward from the horizontal direction. A large number of holes 12 (only part of which are shown in FIG. 1) through which water and air can flow are formed in the peripheral wall portion of the drum 11, and a plurality of baffles 13 (only one in FIG. 1) are formed on the inner surface of the peripheral wall portion. Is shown). An annular balance ring 14 is provided at the front portion of the drum 11, and an opening 15 in the inner peripheral portion of the balance ring 14 communicates with the laundry entrance 4. The drum 11 is directly rotated by a drum motor 16 provided on the back side of the water tank 6. The drum motor 16 is constituted by, for example, an outer rotor type DC brushless motor, and functions as a driving unit for the drum 11. In the drum 11, the laundry is accommodated so as to be able to be taken in and out from the laundry entrance 4. The drum 11 functions as a shared tank for washing, rinsing and dehydrating laundry.

  One end of a drainage duct 20 is connected to a drainage port 19 provided at the lowermost part of the rear part of the water tank 6. As shown in FIG. 3, the other end of the drainage duct 20 is connected to the inlet of the filter case 22 of the filter unit 21 that constitutes the lint capturing unit. A filter cap 23 is detachably attached to the front portion of the filter case 22, and a lint filter (not shown) is provided on the filter cap 23. Therefore, the lint filter is detachably attached to the filter case 22 via the filter cap 23.

  A circulation pump unit 25 is provided on the downstream side of the filter unit 21 so as to be positioned on the base plate 3. The circulation pump 26 of the circulation pump unit 25 includes a pump unit 27 and a pump motor 28, and exerts a pump action by rotating an impeller (not shown) provided in the pump unit 27 by the pump motor 28. The pump motor 28 is provided with a cooling fan 28a that is positioned opposite to the pump unit 27 and rotated by the pump motor 28. When the pump motor 28 is driven, the pump motor 28 itself is driven by the cooling fan 28a. It can be cooled. The cooling fan 28a is not necessarily required, and may be provided as necessary.

  One end of a circulation duct 29 is connected to the discharge port 27a (see FIG. 4) of the pump unit 27. The other end of the circulation duct 29 extends upward and is connected to a discharge port 30 provided in the upper part of the water tank cover 8. As shown in FIG. 5, the discharge port 30 has an opening 30a that is open on the rear side (drum 11 side) of the tip, and water supplied from the circulation duct 29 is supplied from the opening 30a to the drum. 11 is discharged toward the rear part. As illustrated in FIG. 5B, the opening 30 a has a semicircular shape that is long in a direction orthogonal to the axial direction of the drum 11. A drain valve 32 is connected to the downstream side of the circulation pump unit 25 via a connection pipe 31 (see FIG. 3), and a drain hose 33 is connected to the drain valve 32.

  Here, the drainage duct 20, the filter case 22 of the filter unit 21, the pump part 27 of the circulation pump unit 25, and the circulation duct 29 constitute a circulation water channel 34. Further, the circulating water channel 34, the circulation pump unit 25, and the discharge port 30 constitute a circulation watering device 35.

  In this case, when water is supplied into the aquarium 6 with the drain valve 32 closed, the water is discharged from the drain port 19, the drain duct 20, the filter case 22, the pump portion 27 of the circulation pump unit 25, and the connection pipe. It is stored by entering through 31 and before the drain valve 32. The water supplied more than that is stored in the water tank 6. When the pump motor 27 of the circulation pump 26 is driven in this state, the water in the water tank 6 is sucked into the pump portion 27 through the drainage duct 20 and the filter case 22 by the pump action of the circulation pump 26, and the pump The water in the section 27 is discharged from the discharge port 27a to the circulation duct 29 side, passes through the circulation duct 29, and is discharged from the discharge port 30 into the drum 11 and eventually into the water tank 6. Water is circulated through the circulation channel 34 (see arrow A in FIGS. 1 and 2). When the drain valve 32 is opened in a state where water is stored in the water tank 6, the water in the water tank 6 flows from the drain port 19 to the drain duct 20, the filter case 22, and the pump part of the circulation pump unit 25. 27, discharged through the connection pipe 31, drain valve 32 and drain hose 33 to the outside of the machine.

  An overflow port 36 is provided in the outer peripheral part slightly below the center of the water tank cover 8, and the upper end of an overflow duct 37 is connected to the overflow port 36. The lower end of the overflow duct 37 is connected to a portion of the drain hose 33 near the drain valve 32. Therefore, when the water in the water tank 6 exceeds the overflow port 36, the water is discharged from the overflow port 36 through the overflow duct 37 and the drain hose 33 to the outside of the apparatus.

An operation panel 40 provided with an operation unit 38 and a display unit 39 (see FIG. 6) is provided at the upper part of the front surface of the outer box 1, and a control device 41 including a microcomputer is provided on the back side of the operation panel 40. ing. This control device 41 constitutes the control means of the present invention. A water supply valve 42 is provided at the rear part of the upper part in the outer box 1, and a water supply case 43 is provided at the front part, and an outlet of the water supply valve 42 is connected to the water supply case 43 through a water supply pipe 44. . Although not shown, a hose connected to a water tap is connected to the water inlet 42a of the water supply valve 42. A detergent is introduced into the water supply case 43. The lower part of the water supply case 43 is connected to a water supply port 46 provided in the upper part of the water tank 6 through a water supply hose 45.
In this case, when the water supply valve 42 is opened, tap water is supplied to the water supply case 43 via the water supply pipe 44, and the water is supplied to the water tank 6 via the water supply hose 45 together with the detergent introduced into the water supply case 43. Of these, the drum 11 is supplied.

  FIG. 6 shows an electrical schematic configuration related to the gist of the present invention. 6, the control device 41 includes an operation unit 38 provided on the operation panel 40, a water level sensor 50 for detecting the water level in the water tank 6, a rotation sensor 51 for detecting the rotation speed of the drum motor 16, and a pump motor. Signals from a rotation sensor 52 for detecting the rotation speed 28 and a current transformer 53 for detecting an input current of the pump motor 28 are input. The rotation sensors 51 and 52 are composed of Hall elements, for example. The current transformer 53 constitutes a state detection unit that detects the operation state of the pump motor 28. Based on these input signals and a control program prepared in advance, the control device 41 includes a display unit 39, a water supply valve 42, a drum motor 16, a pump motor 28 of the circulation pump 26, and a drain valve 32 provided on the operation panel 40. It has a function to control.

Next, the operation of the above configuration will be described.
When washing, first, the user opens the door 5, puts laundry (not shown) into the drum 11 from the laundry entrance 4 and puts a necessary detergent, for example, powder detergent, into the water supply case 43. To do. Then, with the door 5 closed, the operation unit 38 of the operation panel 40 is operated to set the operation condition and start the operation. Then, the control device 41 starts the washing operation based on the control program stored in advance. To do.

  The control device 41 first detects the amount (weight) of the laundry stored in the drum 11. For example, the amount of laundry is detected as follows. The drum 11 is rotated by rotating the drum motor 16 in one direction with a predetermined constant electric power for a predetermined time, the rotation speed is detected by the rotation sensor 51, and the laundry speed is detected by the degree of fluctuation of the rotation speed. The amount is determined in three stages, for example, large capacity, medium capacity, and small capacity. The control device 41 determines the water level according to the amount of laundry.

  Next, the control device 41 supplies water to the water tank 6 and thus to the drum 11 by opening the water supply valve 42 with the drain valve 32 closed. When the water supply valve 42 is opened, as described above, tap water is supplied to the water supply case 43 via the water supply pipe 44, and the water is supplied to the water supply case 43 through the water supply hose 45 together with the detergent. It is supplied into the water tank 6 and eventually into the drum 11. A part of the water and detergent supplied into the water tank 6 enters and is stored in front of the drainage valve 32 through the drainage duct 20, the filter case 22, the pump unit 27 of the circulation pump unit 25, and the connection pipe 31. At this time, the detergent has many undissolved parts. The water level in the water tank 6 is detected by the water level sensor 50, and when the set water level is reached, the water supply valve 42 is closed. The set water level is set according to the amount of laundry.

  If water supply is completed, the control apparatus 41 will perform a washing process next. In the washing process, the drum 11 is alternately rotated by the drum motor 16 in both forward and reverse directions at a rotational speed of, for example, 50 to 60 rpm. Thereby, the laundry in the drum 11 is repeatedly swung up by the baffle 13 and dropped, and the laundry is washed.

In this washing process, the pump motor 28 of the circulation pump 26 is also driven along with the rotation of the drum 11. When the pump motor 28 is driven, the impeller in the pump unit 27 rotates, and as described above, the water in the water tank 6 passes through the drain duct 20 and the filter case 22 by the pump action by the rotation of the impeller. The water in the pump unit 27 is discharged from the discharge port 27 a to the circulation duct 29, passes through the circulation duct 29, and is discharged from the discharge port 30 into the drum 11 and eventually into the water tank 6. Thus, the water in the water tank 6 is circulated through the circulation water channel 34. At this time, in order to circulate the water in the water tank 6 and discharge the water from the discharge port 30 on the upper part of the water tank cover 8, a lift of 7.84 [kPa] (80 cmH ₂ O) or more is required.

  FIG. 7 shows a control example of a change in the rotational speed of the pump motor 28 in the circulation pump 26. FIG. 7 shows an example where the amount of laundry is large. At the beginning of the washing process, the pump motor 28 is driven at, for example, 3000 rpm (initial rotation speed) higher than the normal rotation speed (for example, 2500 rpm) in order to actively dissolve the undissolved detergent (see B1 in FIG. 7). ). Thereby, dissolution of the detergent contained in water is promoted by stirring the impeller in the pump unit 27. Further, when the pump motor 28 is driven at a high rotational speed, a high-capacity cleaning liquid is circulated and ejected from the discharge port 30 into the drum 11 at a high pressure. In this case, since the shape of the opening 30a in the discharge port 30 is long in the direction orthogonal to the axial direction of the drum 11, the water discharged from the opening 30a spreads in a wide range in the drum 11 (Refer to C1 in FIG. 8). Thereby, many washing | cleaning liquids can be poured with respect to the laundry located in the back in the drum 11. FIG. The laundry in the drum 11 is dropped almost once by the rotation of the drum 11 while turning over in a lump state, and the washing liquid from the discharge port 11 is applied thereto. In this way, the washing efficiency is improved by actively applying the washing liquid to the laundry, and uneven washing of the laundry can be prevented.

  In this case, the initial rotation speed is changed according to the amount of laundry. Specifically, as shown in FIG. 12, the initial rotation speed in the washing process is 3000 rpm as described above when the amount of laundry is large, but when the amount of laundry is medium, In the case of a slightly lower 2900 rpm and a small capacity, the lower 2800 rpm is set. Thereby, according to the amount of the laundry in the drum 11, a washing | cleaning liquid can be poured favorable.

When the pump motor 28 is driven at 3000 rpm for a predetermined time, the rotational speed of the pump motor 28 is reduced to, for example, 1800 rpm (minimum rotational speed) lower than the normal rotational speed (2500 rpm) (see B2 in FIG. 7). Then, as the discharge pressure from the discharge port 30 decreases, the momentum of the cleaning liquid discharged from the discharge port 30 becomes weak (see C2 in FIG. 8), and the cleaning liquid is applied to the laundry near the front portion of the drum 11. Can be applied efficiently. This 1800 rpm is a minimum rotation speed for clearing the head of the circulation water channel 34, in other words, a minimum rotation speed for discharging the cleaning liquid from the discharge port 30. In this way, by increasing or decreasing the rotational speed of the pump motor 28, it becomes possible to evenly apply the washing liquid to the laundry.
In addition, when the water in the water tank 6 is circulated through the circulation channel 34 in this way, the lint that comes out of the laundry is captured by the lint filter of the filter unit 21 located on the upstream side of the circulation pump 26.

  When the circulation pump 26 is operated by continuing the washing operation, the detergent has a strong foaming power and the pump motor 28 is operated at a high rotational speed as long as the detergent is completely dissolved and the dirt is still removed and not melted into the washing liquid. If the operation is continued, excessive bubbles are generated, and the circulation pump 26 causes air damage due to the bubbles. In the worst case, the cleaning liquid cannot be circulated.

  FIG. 9 is a diagram showing the relationship between the rotational speed of the pump motor 28 and the foaming of the detergent. As the rotational speed of the pump motor 28 is increased, foaming gradually increases. When the rotational speed exceeds a certain rotational speed, foaming occurs explosively due to stirring in the pump unit 27. When the detergent is not yet dissolved as in the beginning of washing, foaming is difficult even if the rotational speed is increased, but when the detergent is well dissolved, foaming is likely to occur. FIG. 10 is a diagram showing the relationship between the input current of the circulation pump 26 (pump motor 28) and air gaps. When the air gap starts, the input current of the circulation pump 26 tends to decrease.

  Therefore, when air debris is generated in the circulation pump 26, the rotational speed of the pump motor 28 is decreased to reduce the amount of the circulating cleaning liquid. However, this is negative for cleaning, and it is desired to minimize it. Therefore, the rotational speed of the pump motor 28 is decreased, and the rotational speed to be decreased is determined by feedback from the pump motor 28. FIG. 11 shows the relationship between the rotational speed of the pump motor 28 and the input current of the circulation pump 26. The input current of the circulation pump 26 is detected by a current transformer 53. The input current is substantially proportional to the square of the rotational speed of the pump motor 28 in a state where no air stagnation is generated, but extremely decreases when air stagnation occurs.

  The rotational speed at which the circulation pump 26 begins to bite air varies depending on the amount of detergent, and the air begins to bite as soon as the amount of detergent increases. The control device 41 detects the input current of the pump motor 28, and when the input current becomes smaller than a preset threshold value (for example, 1A), the control device 41 determines that the air has occurred, and the rotation of the pump motor 28 is determined. The speed is reduced by, for example, 50 rpm (see B3 in FIG. 7). Then, the detected input current is sequentially compared with the threshold value, and if it is determined that the input current is small, the input current is decreased by 50 rpm (see B4 in FIG. 7), and the rotation speed is reached to determine that there is no air jam. Reduce the speed (see B5 in FIG. 7). Then, when the air gap is eliminated, the rotational speed of the pump motor 28 is periodically changed again. The higher rotational speed in the middle stage of the washing process where bubbles are likely to occur is set to the normal rotational speed of 2500 rpm (see B6 in FIG. 7).

  In the second half of the washing process, the dirt dissolves, the detergent expires, and foaming decreases. Therefore, control is performed so as to increase the higher rotational speed. At this time, if the rotation speed is increased at once, there is a possibility that air scum will be generated again. Therefore, the rotation speed is gradually increased by 50 rpm (refer to B7 in FIG. 7), contrary to the decrease. The higher rotation speed in the second half is 2800 rpm (see B8 in FIG. 7).

  When the set time for the washing process has elapsed, the rotation of the drum 11 is stopped and the operation of the circulation pump 26 is also stopped. Thereafter, the water in the water tank 6 is discharged outside the apparatus by opening the drain valve 32. When drainage is finished, tap water is supplied into the water tank 6 by opening the water supply valve 42 with the drain valve 32 closed, and stored up to the set water level.

  Thereafter, the first rinsing process (rinse 1) is performed. In the first rinsing process, as in the washing process, the drum 11 is alternately rotated in the forward and reverse directions at a rotational speed of 50 to 60 rpm by the drum motor 16 and the pump motor 28 of the circulation pump 26 is shown in FIG. The drive is controlled as follows. Since the detergent is diluted at the time of rinsing, the generation of foam is less than at the time of the washing process. That is, the pump motor 28 can be operated at a higher rotational speed than during the washing stroke. Therefore, in the first rinsing process, the initial rotational speed of the pump motor 28 is set higher than that in the washing process, for example, 3500 rpm (see B9 in FIG. 7), and the rotational speed is set in the same manner as in the washing process. Change periodically. The minimum rotation speed at this time is also 1800 rpm. Thereby, rinsing can be performed efficiently. Also in the first rinsing process, the input current is compared with the threshold value to determine whether or not air is generated. If it is determined that air is generated, control is performed to decrease by 50 rpm (B10 in FIG. 7). reference). In this case, the rotational speed change amount is also 50 rpm.

  Also in the first rinsing process (rinsing 1), the initial rotational speed of the pump motor 28 is changed depending on the amount of laundry. Specifically, as shown in FIG. 12, the initial rotation speed in the first rinsing process is 3500 rpm as described above when the amount of laundry is large, but 3350 rpm when the volume is medium. In the case of a small capacity, the speed is 3200 rpm. Thereby, according to the amount of laundry in the drum 11, a rinse can be performed efficiently.

  When the first rinsing process is completed, drainage and water supply are performed, and then the second rinsing process (rinsing 2) similar to the first rinsing process is performed. In the second rinsing process, the detergent component is further diluted in comparison with the first rinsing process, so that the rotational speed of the pump motor 28 can be set higher. Specifically, as shown in FIG. 12, the initial rotation speed in the second rinsing process is 3700 rpm when the amount of laundry is large, 3500 rpm when medium, and 3300 rpm when small. And Thereby, according to the amount of laundry in the drum 11, a rinse can be performed efficiently. Also in the second rinsing process, the input current is compared with the threshold value to determine whether or not air is generated. When it is determined that air is generated, control is performed to decrease by 50 rpm. In this case, the rotational speed change amount is also 50 rpm.

  When the second rinsing process is completed, a dehydration process is performed after draining. In the dehydration process, the laundry is centrifugally dehydrated by rotating the drum 11 in one direction at a high speed by the drum motor 16. Thus, the washing operation ends.

According to the above-described embodiment, the following operational effects can be obtained.
Since the pump motor 28 composed of a brushless motor is used as the drive source of the circulation pump 26 in the circulation sprinkler 35, the rotational speed of the pump motor 28 can be easily controlled. And the discharge pressure of the water discharged into the drum 11 from the discharge port 30 of the circulation sprinkler 35 is changed by changing the rotational speed of the pump motor 28 in one stroke (washing stroke or rinsing stroke) during the washing operation. It can be easily changed. By changing the discharge pressure of the water discharged from the discharge port 30, it is possible to change the water discharge direction and the discharge range, so that the entire laundry in the drum 11 can be poured evenly, and the laundry This makes it possible to further improve the cleaning performance and rinsing performance.

  The rotational speed of the pump motor 28 is changed according to the amount of laundry. When the amount of laundry is large (when it is close to the rated capacity), the higher rotational speed of the pump motor 28 is set high, the discharge pressure from the discharge port 30 is increased, and the washing liquid is actively applied to the laundry. By applying the cleaning liquid, it becomes possible to infiltrate the entire cleaning solution more efficiently and uniformly. When the amount of laundry is large, especially when the laundry is dry, the bulk is high, and if the discharge pressure of the cleaning liquid discharged from the discharge port 30 is weak, it is difficult to apply to the entire laundry. In such a case, by increasing the discharge pressure and actively applying the cleaning liquid, the laundry becomes damp quickly and the volume of the laundry in the drum 11 can be reduced. As a result, the cleaning liquid can be applied more efficiently. When the amount of laundry is small, the washing liquid can be applied evenly to the laundry even if the higher rotational speed of the pump motor 28 is set low and the discharge pressure from the discharge port 30 is lowered. Energy saving can be achieved by setting the rotational speed of the pump motor 28 low and reducing the input of the pump motor 28.

  The rotational speed of the pump motor 28 is changed between the washing process and the rinsing process. Specifically, in the washing process, the higher rotational speed of the pump motor 28 is set lower than that in the rinsing process, thereby suppressing the generation of bubbles and the generation of air dirt. In the rinsing process, the detergent concentration is reduced. Therefore, the rinsing efficiency can be improved by setting the higher rotational speed of the pump motor 28 higher.

By setting the rotational speed of the pump motor 28 high at the initial stage of the washing process, the dissolution of the detergent can be promoted and the washing efficiency can be improved.
When the input current of the pump motor 28 is detected by the current transformer 53, it is determined whether or not air circulation has occurred in the circulation pump 26 based on the detection result of the current transformer 53. By changing the rotation speed of the motor 28 so as to decrease, it is possible to operate the circulating watering device 35 satisfactorily while avoiding the occurrence of air stagnation, thereby improving the cleaning efficiency.

The present invention is not limited to the above-described embodiment, and can be modified or expanded as follows.
As an example of detecting the occurrence of air contamination in the circulation pump 26, an example in which the input current of the pump motor 28 is detected by the current transformer 53 has been shown, but instead, the duty for driving the pump motor 28 is made constant, and the pump motor It is also possible to make a judgment based on the 28 rotational speed fluctuations. In this case, it is possible to detect the occurrence of air stagnation as the rotational speed of the pump motor 28 increases.

1 is a longitudinal side view of a washing machine showing an embodiment of the present invention. Broken perspective view Perspective view of base plate, lint filter unit and circulation pump unit Perspective view of lint filter unit and circulation pump unit (A) is a longitudinal side view of the discharge port portion, (b) is a view of the discharge port as viewed from the direction of arrow X in (a). Electrical configuration block diagram Diagram showing changes in pump motor rotation speed The figure which shows the discharge range of the water discharged from a discharge outlet The figure which shows the relationship between the rotational speed of the pump motor and foaming (air gap) Diagram showing the relationship between air gap (bubbles) and input current Diagram showing the relationship between the rotational speed of the pump motor and the input current The figure which shows the relationship between the amount of laundry in each process, the initial rotational speed of a pump motor, the minimum rotational speed, the rotational speed change amount, and an air-gear determination threshold value.

Explanation of symbols

  In the drawings, 1 is an outer box, 6 is a water tank, 11 is a drum, 16 is a drum motor (drive means), 21 is a filter unit, 25 is a circulation pump unit, 26 is a circulation pump, 27 is a pump unit, and 28 is a pump. A motor, 29 is a circulation duct, 30 is a discharge port, 34 is a circulation water channel, 35 is a circulation watering device, 41 is a control device (control means), and 53 is a current transformer (state detection means).

Claims (5)

A water tank capable of storing water,
A drum that has a hole through which water can pass and is rotatably disposed in the water tub, in which laundry is accommodated and rotated by driving means;
In a washing machine comprising a circulating watering device that circulates by circulating the water in the water tank through the circulation water channel by the pumping action of a circulation pump and discharging the water from the discharge port into the water tank,
The circulating pump uses a pump motor composed of a brushless motor as a drive source, and includes a control means for controlling the rotational speed of the pump motor,
The washing machine according to claim 1, wherein the control means changes a rotation speed of the pump motor within one stroke during a washing operation.   2. The washing machine according to claim 1, wherein the control means changes the rotational speed of the pump motor in accordance with the amount of laundry accommodated in the drum.   The washing machine according to claim 1 or 2, wherein the control means changes a rotation speed of the pump motor between a washing process and a rinsing process.   The washing machine according to any one of claims 1 to 3, wherein the control means increases the rotational speed of the pump motor at an initial stage of a washing process. Comprising a state detecting means for detecting an operating state of the pump motor;
The washing machine according to any one of claims 1 to 4, wherein the control means changes a rotation speed of the pump motor based on a detection result of the state detection means.

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