WO2011007540A1

WO2011007540A1 - Washing machine

Info

Publication number: WO2011007540A1
Application number: PCT/JP2010/004505
Authority: WO
Inventors: 大山眞; 安井利彦; 久保光市
Original assignee: パナソニック株式会社
Priority date: 2009-07-14
Filing date: 2010-07-12
Publication date: 2011-01-20
Also published as: JP2011019607A; EP2455529A4; US20120103026A1; TW201109493A; EP2455529A1; CN102471974A

Abstract

A washing machine is provided with an outer tub (24) which is supported within a housing (21), an inner tub (25) which is rotatably provided within the outer tub (24) and contains and stirs laundry, a circulation path (37) which sucks a wash liquid held in the outer tub (24) and returns the wash liquid again to the inside of the outer tub (24), and a circulation pump (39) which is provided in the middle of the circulation path (37) and circulates the wash liquid. Also, a wash-liquid-condition detection section (40) which detects the condition of the wash liquid is provided in the middle of the circulation path (37), and this enables a sufficient amount of circulation of the wash liquid flowing through the wash-liquid-condition detection section (40) to be ensured without dependent on the operation of the inner tub (25). As a result, the accuracy of detection of the degree of soiling of the wash liquid can be maintained at a high level without a reduction in the cleaning performance of the washing machine.

Description

Washing machine

The present invention relates to a washing machine that controls operation according to the state of the washing liquid.

As a conventional washing machine, for example, there is a washing machine disclosed in Patent Document 1. FIG. 10 is a cross-sectional view of a washing machine disclosed in Patent Document 1. As shown in FIG. 10, the washing machine includes a housing 1, an outer tub 2 supported inside the housing 1, and a bottomed cylindrical inner tub 3 that is rotatably provided inside the outer tub 2. And a drive motor 4 for rotating the inner tub 3. The rotation axis of the inner tank 3 is horizontal. The inner tub 3 accommodates laundry such as clothes. A circulation path 5 through which the washing liquid circulates is provided outside the outer tub 2. A turbidity sensor 6 for detecting the turbidity of the washing liquid is attached to the circulation path 5.

The washing liquid circulates in the circulation path 5 by the rotation of the inner tub 3. Thereby, detergent and dirt do not accumulate at the bottom of the outer tub 2. Further, the concentration of the washing liquid in the outer tub 2 and the washing liquid in the circulation path 5 is made uniform. Since the concentration of the washing liquid is made uniform, the degree of contamination of the washing liquid can be detected by detecting the turbidity of the washing liquid. That is, the turbidity sensor 6 detects the degree of contamination of the washing liquid. The control unit 7 determines the dirt on the laundry based on the detected degree of dirt on the washing liquid. The controller 7 shortens the washing time when there is little dirt and optimally controls the washing time.

The conventional washing machine circulates the washing liquid in the circulation path 5 by the rotation of the inner tub 3. Therefore, it is necessary to increase the rotational speed of the inner tub 3 in order to ensure a sufficient circulation amount of the washing liquid. On the other hand, the inner tub 3 functions as a stirring unit that stirs the laundry by rotation. That is, the laundry is lifted by the rotation of the inner tub 3, and then the laundry is dropped, thereby washing. This washing is called tapping. In this case, the inner tank 3 has an optimum rotation speed. When the inner tub 3 rotates at a rotation speed higher than the optimum rotation speed, the laundry is attached to the inner surface of the inner tub 3 and rotates. In such a state, the washing performance of the washing machine is deteriorated because tapping is not performed. The conventional washing machine rotates the inner tub 3 at an optimum rotation speed in order to maintain the washing performance by tapping. Therefore, the circulation amount of the washing liquid in the circulation path 5 is not sufficiently ensured. Thereby, equalization of the washing liquid in the outer tub 2 and the washing liquid in the circulation path 5 is delayed, and the detection accuracy of the turbidity sensor 6 is lowered.

JP-A-4-240485

The present invention provides a washing machine that maintains the detection accuracy of the degree of contamination of the washing liquid without deteriorating the washing performance.

The washing machine of the present invention includes a housing, an outer tub supported inside the housing, an inner tub that accommodates laundry and is rotatably provided inside the outer tub, and an agitation unit that agitates the laundry With. Furthermore, the washing machine of the present invention includes a circulation path that sucks the washing liquid accumulated in the outer tub and returns it to the inside of the outer tub, a circulation pump that is provided in the middle of the circulation path and circulates the washing liquid, and an agitator and a circulation pump. The control part which controls operation | movement of this. Furthermore, the washing machine of the present invention includes a washing liquid state detection unit that detects the state of the washing liquid in the middle of the circulation path.

With this configuration, it is possible to secure the circulation amount of the washing liquid flowing through the washing liquid state detection unit without depending on the operation of the stirring unit. Therefore, the detection accuracy of the degree of contamination of the washing liquid is maintained without deteriorating the cleaning performance.

1 is a cross-sectional view of a washing machine according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of the discharge port of the washing machine in the same embodiment. FIG. 3 is a cross-sectional view of another discharge port of the washing machine in the same embodiment. FIG. 4 is a sectional view of another washing machine according to the embodiment. FIG. 5 is a cross-sectional view of the washing liquid state detection unit of the washing machine in the same embodiment. FIG. 6 is a cross-sectional view showing another operation of the discharge port of the washing machine in the same embodiment. FIG. 7 is a cross-sectional view of another washing machine according to the embodiment. FIG. 8 is a cross-sectional view of another washing machine according to the embodiment. FIG. 9 is a sectional view of another washing machine according to the embodiment. FIG. 10 is a cross-sectional view of a conventional washing machine.

(Embodiment 1)
1 is a cross-sectional view of a washing machine according to Embodiment 1 of the present invention. An outer tub 24 supported by a spring 22, a damping portion 23, or the like that is a support portion is provided inside the housing 21. An inner tank 25 is rotatably provided in the outer tank 24. A drive motor 26 for rotating the inner tank 25 is provided on the back surface (right side in FIG. 1) of the outer tank 24. This washing machine is a so-called drum type washing machine, and the rotation axis of the inner tub 25 is inclined to be higher in the front (left side in FIG. 1) than the horizontal or horizontal. The door body 27 provided in the housing 21 opens and closes the front opening 24 a of the outer tub 24. The casing 21 and the door body 27 are sealed with a water seal packing 28. A plurality of protrusions 29 are provided on the inner surface of the cylindrical portion of the inner tank 25. The protrusion 29 lifts the laundry upward when the inner tub 25 is rotated at a low speed.

A water supply valve 30 having a water supply port 30a for connecting one end of a water supply hose (not shown) and a detergent charging unit 31 for a user to add a detergent in advance are provided on the upper portion of the housing 21. . Further, a water supply path 32 for connecting the water supply valve 30 and the detergent charging unit 31 and the detergent charging unit 31 and the outer tub 24 is provided. The other end of the water supply hose is connected to the water supply.

A water intake 33 is provided at the bottom of the outer tub 24. The water intake 33 is connected to a drainage path 36 via a drainage filter 34 and a drainage valve 35. The washing liquid is discharged from the drainage path 36 to the outside of the washing machine. A circulation path 37 branched from between the water intake 33 and the drain valve 35 is provided. The washing liquid taken from the water intake port 33 is returned to the outer tub 24 again by the circulation path 37. A discharge port 38 that is an outlet of the circulation path 37 is provided in the outer tub 24. The discharge port 38 ejects the washing liquid toward the inside of the inner tub 25. The route from the intake port 33 to the discharge port 38 is collectively referred to as a circulation route 37. The circulation path 37 is provided with a circulation pump 39 for circulating the washing liquid through the circulation path 37 and a washing liquid state detection unit 40 for detecting the state of the washing liquid. In addition, although the circulation path 37 demonstrated the case where it branched from between the water intake 33 and the drain valve 35, it is connected with the water intake (not shown) provided separately from the water intake 33 of the water discharge path 36, and is comprised. You can also

FIG. 2 is a sectional view of the discharge port 38 of the circulation path 37 of the washing machine in the present embodiment. The discharge port 38 is provided between the outer tub 24 and the inner tub 25, and sprays the washing liquid toward the inside of the inner tub 25 through the gap between the outer tub 24 and the inner tub 25. A state of jetting the washing liquid is shown in FIG. As shown in the cross-sectional view of FIG. 3, the discharge port 38 may be configured so that the discharge port 38 is provided in an exposed portion of the outer tank 24 and sprayed toward the inside of the inner tank 25. FIG. 3C shows how the washing liquid is jetted in this case. Further, as shown in the sectional view of FIG. 4, a discharge port 38 is provided between the outer tub 24 and the inner tub 25, and the washing liquid is not sprayed into the inner tub 25. It can be set as the structure which injects a washing | cleaning liquid in between.

FIG. 5 is a cross-sectional view of the washing liquid state detection unit 40. The washing liquid state detection unit 40 includes an optical sensor 41 that detects the turbidity of the washing liquid and an electrode sensor 42 that detects the conductivity of the washing liquid. The optical sensor 41 includes a light emitting element 43 and a light receiving element 44. The light emitting element 43 is, for example, an LED, and the light receiving element 44 is, for example, a phototransistor. The light emitting element 43 and the light receiving element 44 are installed opposite to each other at a substantially horizontal position with the circulation path 37 interposed therebetween. The electrode sensor 42 includes a pair of electrodes 45 a and 45 b on one side of the side wall of the circulation path 37.

The control unit 46 controls the operation of the drive motor 26, the water supply valve 30, the drain valve 35, the circulation pump 39, and the like. Further, the control unit 46 reads the output from the washing liquid state detection unit 40 and performs calculations. As a result, the degree of contamination of the washing liquid is detected.

Next, the operation of the washing machine of this embodiment will be described. The user opens the door body 27, puts laundry such as clothes into the inner tub 25, and closes the door body 27. When the start button is pushed, the operation of the washing machine is started. When the operation is started, the control unit 46 drives the drive motor 26 and estimates the amount of clothing from the load of the drive motor 26 and the like. The control unit 46 displays a necessary amount of detergent on a display unit (not shown) according to the estimated amount of clothing. The user pulls out the detergent insertion part 31, introduces the detergent based on the displayed amount of detergent, and pushes the detergent insertion part 31 back to the original position again.

The control unit 46 opens the water supply valve 30 after a predetermined time has elapsed. When the water supply valve 30 is opened, water is supplied from a water supply (not shown). The supplied water is supplied to the outer tub 24 through the water supply path 32. At this time, since the water passes through the detergent charging unit 31 in which the detergent is charged, it becomes a washing liquid containing the detergent and is supplied to the outer tub 24.

The control unit 46 drives the drive motor 26 almost simultaneously with the start of water supply, whereby the inner tank 25 rotates. When the washing liquid (water) reaches a predetermined amount of water, the water supply valve 30 is closed. On the other hand, the rotation of the inner tank 25 is continued. Since the three protrusions 29 are provided on the inner surface of the inner tub 25, the clothes are lifted when the inner tub 25 rotates. Thereafter, the laundry leaves the inner surface of the inner tub 25 and falls above the inner tub 25. This tapping washing promotes washing of the laundry. There is a suitable rotational speed for tapping, and the cleaning performance is degraded whether the rotational speed is higher or lower.

The control unit 46 opens the drain valve 35 after washing the clothes for a predetermined time. As a result, the washing liquid is drained from the washing path 36 to the outside of the washing machine. Then, the control part 46 performs the spin-drying | dehydration step which rotates the inner tank 25 at high speed and reduces the washing | cleaning liquid which remained in the laundry. Then, the control part 46 stops the inner tank 25, opens the water supply valve 30, supplies water to a predetermined water level, rotates the inner tank 25 again, and performs a rinse step. This dehydrating step and rinsing step are repeated about twice, and finally the dehydrating step is executed, and the series of steps is completed with the laundry being dehydrated.

Next, the operation of the washing liquid state detection unit 40 will be described. The optical sensor 41 detects the turbidity of the washing liquid. The portion of the circulation path 37 that is sandwiched between the light emitting element 43 and the light receiving element 44 is formed of a translucent resin material. As a result, the light from the light emitting element 43 passes through the washing liquid in the circulation path 37 and is received by the light receiving element 44. The light receiving element 44 outputs a signal corresponding to the intensity of the received light. The control unit 46 such as a microcomputer takes in this signal, converts it into a voltage, and outputs it. The light passing through the washing liquid is attenuated according to the degree of turbidity of the washing liquid. For example, when the amount of light received by the light receiving element 44 is small, the degree of turbidity of the washing liquid is large. That is, the washing liquid is dirty. Conversely, when the amount of light received by the light receiving element 44 is large, the degree of turbidity of the washing liquid is small. In this way, the turbidity of the washing liquid is quantitatively detected from the amount of light received by the light receiving element 44. Since the dirt contained in the laundry dissolves in the washing liquid and the washing liquid becomes cloudy, it can be estimated that the amount of dirt attached to the laundry is large when the washing liquid has a high degree of cloudiness.

On the other hand, the electrode sensor 42 measures the conductivity of the washing liquid. The conductivity is measured by, for example, forming an RC oscillation circuit with the impedance of the washing liquid between the electrodes 45a and 45b and the capacitor (not shown) of the control circuit, and changing the impedance of the washing liquid with a frequency change. And the frequency change is converted into a voltage value. Since electrolyte components such as sweat contained in the laundry are dissolved in the laundry liquid, the conductivity of the laundry liquid is high when there is a lot of dirt such as sweat contained in the laundry. That is, by quantitatively detecting the conductivity of the washing liquid, the amount of dirt such as sweat attached to the laundry can be estimated.

In this manner, the degree of dirt on the laundry such as clothes is estimated by the optical sensor 41 and the electrode sensor 42. Specifically, for example, the degree of contamination is estimated by detecting a temporal change in the outputs of the optical sensor 41 and the electrode sensor 42 and performing a calculation such as taking a difference between certain periods. Alternatively, the degree of contamination is estimated by combining the output results of both the optical sensor 41 and the electrode sensor 42. Operation control of the washing step and the rinsing step is performed according to the estimated degree of dirt on the laundry. That is, when there is little dirt on the laundry, the time for the washing step is shortened. Alternatively, the amount of water used in the washing step and rinsing step is reduced. Thereby, water saving, power saving, and shortening of operation time are performed.

Here, the degree of turbidity of the washing liquid varies depending on the detergent contained in the washing liquid. In addition, the conductivity of the washing liquid may increase depending on the components of the detergent contained in the washing liquid. For this reason, depending on the timing detected by the washing liquid state detection unit 40, such as immediately after water supply, it is possible to distinguish the type and amount of detergent. As described above, the washing liquid state detection unit 40 may detect not only the degree of contamination of the washing liquid but also the state of the washing liquid such as the type and amount of the detergent included based on the degree of turbidity and conductivity of the washing liquid. it can.

In order to increase the correlation between the detection result by the washing liquid state detection unit 40 and the amount of dirt adhering to clothing, it is necessary to devise a determination algorithm such as the absolute value of the detection value and the change rate of the detection value. . In the present embodiment, since the washing liquid state detection unit 40 is provided in the circulation path 37, the structure that prevents the dirt from adhering to the optical sensor 41, the electrode sensor 42, or the like, or the influence of stirring of the washing liquid is affected. It can be configured to be difficult to receive. Therefore, any determination algorithm contributes to the improvement of detection accuracy, and the determination algorithm is not limited. For example, the degree of stain of the washing liquid can be determined on the assumption that the degree of dirt on the laundry, and in this case, depending on the degree of dirt of the laundry liquid, the operation time in the washing step and the rinsing step of the washing machine The amount of water is controlled.

In addition, although it demonstrated using the optical sensor 41 and the electrode sensor 42 as the washing | cleaning liquid state detection part 40, even if it is any one, the stain | pollution | contamination degree of a washing | cleaning liquid is detectable. Moreover, although the case where the optical sensor 41 and the electrode sensor 42 were used in order to measure the turbidity and electrical conductivity of a washing liquid was demonstrated, another sensor can be used.

It is desirable to shield the light receiving element 44 of the optical sensor 41 so as not to be affected by external light. However, when infrared rays are used as the optical sensor 41, light shielding is unnecessary, and the configuration can be simplified.

The washing liquid that circulates in the circulation path 37 includes particles such as foam and sand. Since bubbles are lighter than water, they gather above the inside of the circulation path 37, and particles such as sand gather below the inside of the circulation path 37 because they are heavy. Therefore, if the light emitting element 43 and the light receiving element 44 are provided in a substantially horizontal direction across the vicinity of the center of the circulation path 37, the detection accuracy is improved. However, the present invention is not limited to this configuration, and it is possible to detect the degree of turbidity of the washing liquid even when the light emitting element 43 and the light receiving element 44 are provided in the vertical direction, the oblique direction, or one side of the circulation path 37. is there.

Similarly, by providing the electrode 45a and the electrode 45b in the vicinity of the center in the vertical direction of the circulation path 37, the influence of bubbles is reduced and the conductivity is detected with higher accuracy. Note that the present invention is not limited to this configuration, and the conductivity of the washing liquid can be detected even when the electrode 45a and the electrode 45b are provided facing each other in the vertical direction or the diagonal direction with the circulation path 37 interposed therebetween. .

By driving the circulation pump 39, the washing liquid accumulated in the outer tub 24 is sucked from the water intake port 33, passes through the washing liquid state detection unit 40 and the drainage filter 34, and is discharged from the discharge port 38 to the inside of the inner tub 25. It is injected toward The washing liquid cleans the laundry and is sucked again from the water intake 33. Thus, by circulating the washing liquid accumulated in the outer tub 24, the dirt concentration of the washing liquid becomes more uniform. That is, the degree of dirt of the washing liquid detected by the washing liquid state detection unit 40 and the degree of dirt of the washing liquid in the outer tub 24 are substantially the same. For this reason, by providing the washing liquid state detection unit 40 in the circulation path 37, the degree of contamination of the washing liquid can be detected more accurately and quickly. That is, it is possible to determine the contamination at an early stage. In addition, by spraying the circulated washing liquid onto the clothes, the clothes can be quickly wetted after the start of the washing step. Further, the cleaning power is increased by the mechanical force due to the spraying of the washing liquid.

With the above configuration, the circulation of the washing liquid is forcibly performed by the circulation pump 39. Therefore, the circulation of the washing liquid is performed regardless of the rotation of the inner tub 25 that is a stirring unit for stirring clothes. That is, even when the rotational speed of the inner tub 25 is low, the washing liquid can be sufficiently circulated. In addition, it is possible to arbitrarily set the circulation amount and the circulation timing of the washing liquid so as not to be affected by the operation of the stirring unit. For this reason, it is possible to perform control to increase the detection accuracy of the degree of contamination of the washing liquid without impairing the cleaning power. Further, by increasing the circulation amount of the washing liquid, it is possible to prevent the dirt from adhering to the washing liquid state detection unit 40.

Furthermore, also in the rinsing step, by driving the circulation pump 39, the washing liquid with less dirt components circulates through the washing liquid state detection unit 40. As a result, the washing liquid with a small amount of dirt components cleans the washing liquid state detection unit 40. That is, the detergent component and dirt adhering at the washing step are removed, and the deterioration of the detection performance of the washing liquid state detection unit 40 is suppressed.

In addition, although the discharge port 38 of the circulation path 37 demonstrated the structure provided in one place under the outer tank 24, the circulation path 37 is branched, the discharge port 38 is provided in several places, and it goes to the inner tank 25. The structure which injects washing liquid simultaneously may be sufficient. Moreover, you may comprise the discharge port 38 which injects between the inner tank 25 and the outer tank 24 from the part which branched the circulation path 37 into plurality.

In addition, the circulation pump 39 is intermittently operated repeatedly during driving and stopping during the washing step and the rinsing step. When the circulation pump 39 is driven, bubbles and dirt particles are mixed and circulated in the washing liquid, so that the degree of dirt is detected to be large, and the detection value varies greatly. For this reason, the washing liquid state detection unit 40 performs stable and highly accurate detection by detecting the state of the washing liquid while the circulation pump 39 is stopped. Therefore, the estimation accuracy of dirt is improved. Further, even after the circulation pump 39 is stopped, the detected value is not stable for a while due to the influence of bubbles or the like. For this reason, the detection is performed after the circulation pump 39 is stopped for a predetermined time. Alternatively, when the detected turbidity change width becomes equal to or less than a predetermined value, the detection accuracy is improved by adopting it as a detection value. Further, by performing an operation such as averaging a plurality of detection values, errors are further eliminated and detection accuracy is increased. Further, the washing liquid state detection unit 40 can always perform measurement such as 1 second intervals and use only necessary information.

Also, the electrode sensor 42 is the same as the optical sensor 41, and the measurement accuracy is improved by measuring when the circulation pump 39 is stopped. Note that the turbidity detection by the optical sensor 41 and the conductivity detection by the electrode sensor 42 do not have to be performed at the same timing, and may be performed at a timing according to each feature. If there is no problem in accuracy, the degree of dirt on the laundry may be detected by detecting the degree of dirt on the laundry while the circulation pump 39 is being driven.

In addition, the circulation of the washing liquid to the circulation path 37 is not performed by the rotation of the inner tub 25 that is the agitation unit, but is performed by the circulation pump 39. The circulation of can be stopped. For this reason, high detection accuracy can be obtained while ensuring cleaning power. Furthermore, by changing the rotational speed of the circulation pump 39 according to the progress of the washing step and the rinsing step, higher detection accuracy can be obtained in consideration of the penetration of the washing liquid into the clothes, the degree of foaming, and the like. it can.

Further, the washing liquid in the outer tub 24 is stirred by the rotation of the inner tub 25 that is a stirring portion. For this reason, the rotation of the inner tub 25 affects the detection of the washing liquid state detection unit 40 and causes a detection error. This detection error is reduced by synchronizing the operation of the circulation pump 39 and the operation of the drive motor 26 (that is, the rotation of the inner tank 25). That is, the control unit 46 drives and stops the circulation pump 39, drives the drive motor 26 in the forward direction (hereinafter referred to as forward rotation), and stops and drives in the direction opposite to the forward direction (hereinafter referred to as inversion). Say). Thereby, the detection by the washing liquid state detection unit 40 is performed under a certain condition. Specifically, for example, the controller 46 repeats the operation of driving the circulation pump 39 for 1 minute and then stopping for 1 minute. This 2 minutes is one cycle. In this case, the control unit 46 repeats the operation of rotating the drive motor 26 normally for 30 seconds and then reversing for 30 seconds in one cycle twice. In this way, the operations of the circulation pump 39 and the drive motor 26 are synchronized. Note that the above-described method of synchronization is an example, and the drive time and the stop time, or the forward rotation time and the inversion time are not necessarily the same. Moreover, you may change the rotational speed of the circulation pump 39 in the middle. Further, the synchronization method may be changed during the washing step.

Further, when the control unit 46 stops the drive motor 26 and stops the rotation of the inner tank 25 after a predetermined time after the circulation pump 39 is stopped, both the circulation pump 39 and the drive motor 26 are stopped. By performing the detection by the washing liquid state detection unit 40 at this time or before and after this time, the error is reduced. In this case, the stop of the drive motor 26 is effective even if it is provided only slightly between the forward rotation and the reverse rotation.

Here, as shown in FIG. 2, the discharge port 38 of the circulation path 37 is provided so as to inject the washing liquid from the gap between the outer tub 24 and the inner tub 25 toward the inside of the inner tub 25. With this configuration, the washing power of the washing machine is improved, for example, the circulated washing liquid hits the laundry such as clothes, and the wetting of the laundry is promoted.

If the rotation speed of the circulation pump 39 is equal to or higher than the predetermined rotation speed, the washing liquid is injected into the inner tub 25 as shown in FIG. Circulate with. On the other hand, if the rotational speed of the circulation pump 39 is equal to or lower than the predetermined rotational speed, the washing liquid circulates inside the outer tub 24 as shown in FIG. That is, by controlling the rotational speed of the circulation pump 39, the washing liquid is switched between a state where the washing liquid does not enter the inside of the inner tub 25 and a state where the washing liquid is sprayed both inside and outside the inner tub 25 as necessary. be able to. The improvement of the detection accuracy of the washing liquid state detection unit 40 will be described below.

After the operation of the washing machine is started, the water supply valve 30 is opened, and the detergent introduced into the detergent introduction unit 31 together with the water supply flows into the outer tub 24. When the circulation pump 39 is driven at a predetermined rotational speed or higher at the stage of water supply, a washing liquid having a high detergent concentration is jetted from the discharge port 38 into the inner tub 25. In this case, when the laundry liquid having a high detergent concentration is absorbed by clothes or the like, the detergent concentration of the laundry liquid accumulated in the outer tub 24 is lowered. The washing liquid immediately after the start of water supply is in a state where only the detergent is dissolved. The washing liquid in this state is detected by the washing liquid state detection unit 40, and the type of the detergent can be identified as a powder detergent or a liquid detergent. Further, this detection result can be used as an initial value of the washing liquid before the start of the washing step. However, if a large amount of the washing liquid in this state is sprayed into the inner tub 25, it is impossible to distinguish between the types of detergents as described above and to use the washing liquid as an initial value. Therefore, in the water supply immediately after the start of washing, the rotational speed of the circulation pump 39 is set to a predetermined rotational speed or less, and the washing liquid does not spray from the discharge port 38 into the inner tub 25 but falls below the outer tub 24. Let This improves the accuracy of detecting the type of detergent and detecting the initial state of the washing liquid before the start of the washing step. In addition, when the circulation of the washing liquid by the circulation pump 39 is stopped in order not to spray the washing liquid onto the clothes, the washing liquid collected in the washing liquid state detection unit 40 and the washing liquid collected in the outer tub 24 are made uniform. Is not performed, the detection accuracy deteriorates. That is, as described above, the washing liquid is dropped from the discharge port 38 to the lower side of the outer tub 24 and is circulated inside the outer tub 24, whereby the dissolution of the detergent is promoted and the washing liquid is made uniform. Thereafter, from the middle of the washing step, the washing effect is enhanced by spraying the washing liquid onto the laundry, and the dissolution of the dirt from the laundry is accelerated, and the amount of dirt can be estimated at an early stage. it can. In this way, by controlling the rotational speed of the circulation pump 39, it is possible to perform highly accurate soil determination using one circulation pump 39 and the circulation path 37.

It should be noted that when the washing liquid is circulated only in the outer tub 24, it is desirable that no washing liquid is injected into the inner tub 25. However, there is no problem as long as the washing liquid splashes or the washing liquid flowing down the outer wall surface of the inner tub 25 enters the inner tub 25 through the holes or gaps in the inner tub 25. Further, the detection accuracy is improved by reducing at least the amount of the washing liquid sprayed into the inner tub 25. That is, when at least the washing liquid does not enter the inner tub 25 and circulates in the outer tub 24, the detection accuracy is improved. In other words, it is not effective only when the washing liquid is not sprayed into the inner tub 25 at all. Even when a part of the washing liquid is sprayed into the inner tub 25, a part of the washing liquid is used. If it is injected between the outer tank 24 and the inner tank 25 and circulates inside the outer tank 24, the detection accuracy is improved.

Further, the state where the washing liquid is not sprayed into the inner tub 25 or the state where the washing liquid is sprayed both inside and outside the inner tub 25 is not effective only at the beginning of water supply. For example, when washing is started and the detergent has a lot of foaming, foaming can be further increased by spraying the washing liquid into the inner tub 25. In addition, foaming can be suppressed by stopping the injection of the washing liquid into the inner tub 25. That is, a decrease in detection accuracy due to bubbles is suppressed. As described above, by controlling the rotational speed of the circulation pump 39, it is possible to switch the injection of the washing liquid without adding a configuration.

Water supplied from the water supply path 32 is supplied between the outer tank 24 and the inner tank 25. As shown in A of FIG. 1, the washing liquid state detection unit 40 is provided below the lowest point inside the inner tub 25. That is, the supplied water reaches the washing liquid state detection unit 40 before entering the inner tub 25.

In the rinsing step, the water supplied from the water supply path 32 reaches the washing liquid state detection unit 40 without passing through laundry such as clothes including dirt and detergent. When the washing liquid state detection unit 40 detects water that does not contain dirt or detergent, it is possible to detect a secular change due to dirt adhering to the washing liquid state detection unit 40 or the like. By correcting the measurement based on the detection result, it is possible to maintain the detection accuracy corresponding to the secular change.

On the other hand, at the time of water supply in the washing step, the water supplied from the water supply path 32 enters the washing liquid state detection unit 40 without entering the inner tub 25 as the washing liquid containing the detergent introduced into the detergent charging unit 31. To reach. For this reason, the detergent component does not adhere to or is absorbed by the clothes or the like, and the washing liquid in which only the detergent is dissolved before the dirt component is melted from the clothes reaches the washing liquid state detection unit 40. By detecting this state, the accuracy of discriminating whether the detergent is a powder detergent or a liquid detergent is increased. Thereby, the accuracy as the initial value of the washing liquid in the washing step is increased, and the accuracy of detection of the degree of contamination of the washing liquid is increased. Based on this result, when there is little dirt, efficient washing, such as shortening the washing time or reducing the amount of water used, can be performed.

Also, as the water supply progresses, the amount of water supply increases and the washing liquid containing the detergent enters the inner tub 25. Since the water supply path 32 supplies the washing liquid between the outer tub 24 and the inner tub 25, the amount of the detergent adhering to or adsorbing on the clothes is smaller than in the case of supplying water directly into the inner tub 25. . Further, even after the amount of water supply is increased and the water is supplied into the inner tub 25, the detection accuracy as the initial value of the washing liquid in the washing step is increased.

Further, by driving the circulation pump 39, the detergent can be dissolved quickly and the washing liquid can be quickly applied to the clothes. In addition, the laundry liquid containing the detergent reaches the laundry liquid state detection unit 40 before the circulation pump 39 is driven, so that the initial state of the laundry liquid is accurately detected before the laundry liquid is bubbled.

Also, in order to improve the washing performance of the washing machine, it is preferable to rotate the inner tub 25 as a stirring unit from an early stage. However, when the inner tub 25 is rotated from an early stage, the washing liquid is foamed. This bubble may reduce the detection accuracy of the washing liquid state detection unit 40. For this reason, before the inner tub 25 is rotated, the washing liquid containing the detergent reaches the washing liquid state detection unit 40. For this reason, the initial state of the washing liquid before the washing liquid is foamed is detected with high accuracy.

On the other hand, the washing liquid accumulated in the outer tub 24 is agitated by the rotation of the inner tub 25 serving as a stirring portion, and the washing liquid becomes foamed. The washing liquid state detection unit 40 is provided at a position away from the water intake 33 in the middle of the circulation path 37, and is provided at a position that does not directly face the inner tub 25. Thereby, the influence which rotation of the inner tub 25 has on the detection of the washing | cleaning liquid state detection part 40 can be restrained few. In addition to providing the washing liquid state detection unit 40 at a position bent with respect to the inner tub 25 as shown in FIG. 1, a partition wall is provided between the inner tub 25 and the washing liquid state detection unit 40, thereby It can be set as the structure which does not oppose the tank 25 directly.

In addition, although the drum type washing machine in which the rotation axis of the inner tub 25 is substantially horizontal has been described, the same effect can be obtained even in other washing machines (pulsator type washing machines) as shown in the sectional view of FIG. Have. In FIG. 7, the same components as those in FIGS. 1 to 6 are described with the same reference numerals. In the washing machine shown in FIG. 7, the rotation axis of the inner tub 25 is vertical. In addition, although rotation of the stirring body 47 provided in the bottom face of the inner tank 25 is operation | movement of a stirring part, it is not limited to this. Further, the water supply path 32 supplies water between the inner tank 25 and the outer tank 24. On the other hand, even if the water supplied from the water supply path 32 is directly supplied to the inside of the inner tub 25, the washing liquid is circulated to the circulation path 37 by the circulation pump 39, and the washing liquid state detection unit 40 is used. The state of the washing liquid can be detected. Even if the washing machine is a washing / drying machine having a drying function, the washing machine has the same effect at the time of washing.

FIG. 8 is a cross-sectional view of another washing machine according to the embodiment of the present invention. The difference from the above washing machine is that a switching valve 48 is provided in the circulation path 37 and the circulation path 37 is branched into an inner tank circulation path 49 and an outer tank circulation path 50. In FIG. 8, the washing machine can switch the circulation path 37 to the inner tank circulation path 49 or the outer tank circulation path 50 by the switching valve 48. Immediately after the start of water supply, the washing liquid does not directly enter the inner tank 25 by switching the path to the outer tank circulation path 50. In this case, it is possible to accurately detect the state in which only the detergent is dissolved in the washing liquid, that is, the initial state. In this case, it is not necessary to reduce the rotation speed of the circulation pump 39 to reduce the circulation amount of the washing liquid, and the circulation amount of the washing liquid can be maintained. That is, the cleaning performance is improved by increasing the dissolution rate of the detergent in the washing liquid. Thereby, it is possible to achieve both the detection accuracy of the washing liquid state detection unit 40 and the washing performance of the washing machine.

In FIG. 8, the switching valve 48 is provided. However, as shown in the sectional view of another washing machine in FIG. 9, a circulation pump 139 that can switch the output path between forward rotation and reverse rotation is provided. By using it, it becomes possible to switch and supply the washing liquid to each of the inner tank circulation path 49 and the outer tank circulation path 50, and the same effect is obtained.

As described above, the washing machine according to the present invention can perform optimum operation control according to the degree of dirt by accurately detecting the degree of dirt of the washing liquid. That is, it can be used for a washing machine other than a washing machine for washing clothes and the like.

21 Housing 24 Outer tank 25 Inner tank (stirring section)
DESCRIPTION OF SYMBOLS 27 Door body 30 Water supply valve 30a Water supply port 31 Detergent input part 32 Water supply path 33 Water intake port 34 Drain filter 35 Drain valve 36 Drain path 37 Circulation path 39 Circulation pump 40 Washing liquid state detection part 41 Optical sensor 42 Electrode sensor 43 Light emitting element 44 Light receiving element 45a, 45b Electrode 46 Control unit 47 Stirrer 48 Switching valve 49 Inner tank circulation path 50 Outer tank circulation path

Claims

A housing,
An outer tub supported inside the housing;
An inner tub that accommodates laundry and is rotatably provided in the outer tub;
An agitation unit for agitating the laundry;
A circulation path for sucking the washing liquid accumulated in the outer tub and returning it to the inside of the outer tub again;
A circulation pump provided in the middle of the circulation path for circulating the washing liquid;
A control unit for controlling the operation of the stirring unit and the circulation pump,
A washing machine provided with a washing liquid state detection unit for detecting the state of the washing liquid in the middle of the circulation path.
The control unit intermittently operates the circulation pump during the washing step,
The washing machine according to claim 1, wherein the washing liquid state detecting unit detects the state of the washing liquid when the circulation pump is stopped.
The washing machine according to claim 1, wherein the circulation path sprays the washing liquid into the inner tub.
The washing machine according to claim 1, wherein the control unit synchronizes driving of the stirring unit and driving of the circulation pump.
The washing machine according to claim 1, wherein the control unit stops driving the stirring unit after a predetermined time after the circulation pump is stopped.
The washing machine according to claim 1, wherein the controller drives the circulation pump during a rinsing step.
The washing machine according to claim 1, wherein the agitation unit is the inner tub, and the laundry is agitated by rotation of the inner tub.
The washing machine according to claim 1, further comprising a stirrer rotatably provided on an inner bottom portion of the inner tub, wherein the stirrer is the stirrer, and the laundry is stirred by rotation of the stirrer.