DRUM WASHING MACHINE

Description

TECHNICAL FIELD

[0001] The present invention relates to a rotatable drum type washing machine for washing laundry such as clothes.

BACKGROUND ART

[0002] Conventionally, a rotatable drum type washing machine of this kind washes laundry by operations shown below.

[0003] First, after laundry has been loaded into a rotatable drum, washing and/or rinsing water is supplied from the outside of the washing machine through a water supply unit. The supplied washing and/or rinsing water is poured into a vessel (for example water tub) that houses the rotatable drum through a detergent case previously inserted with a predetermined amount of detergent. After the washing and/or rinsing water has been poured, the laundry is made sufficiently wet with the washing and/or rinsing water while the rotatable drum is rotated at a low speed.

[0004] Next, the rotatable drum is rotated for a fixed time at a low rotational frequency to such an extent that the laundry does not stick to the wall surface of the rotatable drum. Therefore, the laundry wet with the washing and/or rinsing water is lifted to the upper part of the rotatable drum by rotation of the rotatable drum, and the laundry is then dropped from the upper part of the rotatable drum due to its deadweight. By impact of the dropping, dirt is removed, to clean the laundry.

[0005] However, in the configuration of the above rotatable drum type washing machine, it is difficult to get laundry, having been loaded into the rotatable drum, uniformly wet especially when an amount of laundry is large. This has caused non-uniform cleaning of the laundry, leading to significant deterioration in clearing performance.

[0006] In order to prevent the above non-uniform cleaning, the rotatable drum is first rotated at a predetermined, relatively low rotational frequency to perform beat-washing after pouring of the washing and/or rinsing water. The rotatable drum is then rotated at a higher rotational frequency than the rotational frequency at the time of the beat-washing, to perform squeeze-washing. Here, the predetermined rotational frequency is a rotational frequency at which the washing and/or rinsing water in the laundry is discharged to the outside of the rotatable drum by centrifugal force. At this time, a high rotational frequency of the rotatable drum and the number of times the rotatable drum is rotated at a high speed are controlled in accordance with an amount of cloths of the laundry and a temperature of the washing and/or rinsing water, thereby providing the laundry with a mechanical function necessary for cleaning, to efficiently agitate the laundry.

[0007] There has thus been disclosed a rotatable drum type washing machine which gets laundry uniformly wet to clean the laundry (e.g., see PTL 1).

[0008] That is, the conventional rotatable drum type washing machine of PTL 1 controls rotation of a rotatable drum based at least only on an amount of cloths of laundry and a temperature of washing and/or rinsing water. Further, squeeze-washing and the like are performed by making centrifugal force act on the laundry, to clean the laundry.

[0009] At this time, since an amount of dirt on the laundry and an amount of detergent inserted are unknown, when the rotatable drum is rotated at a high speed to clean the laundry, much unnecessary (more than necessary) foam may be generated in the rotatable drum. It is to be noted that a factor of generation of unnecessarily much foam generally lies in a case where there is a little dirt on the laundry, a case where the detergent has been inserted in an amount not smaller than necessary for cleaning the dirt on the laundry, or some other case.

[0010] However, since the rotatable drum type washing machine has not been configured to control cleaning of laundry based on the state of foam generated in the rotatable drum, there arises a problem of not being able to clean the laundry based on an optimum foam state. This has resulted in occurrence of such a problem where, when too much foam is generated, a load of a motor for rotating the rotatable drum increases due to resistance of the foam, to increase power consumption.

[0011] There have then been disclosed rotatable drum type washing machines for detecting generation of excessive foam in order to optimize washing based on the state of foam (e.g., see PTL 2, PTL 3).

[0012] A rotatable drum type washing machine described in PTL 2 has a configuration to detect generation of excessive foam by an electrode and spray cool water onto the foam to remove the excessive foam.

[0013] Further, a rotatable drum type washing machine described in PTL 3 is a rotatable drum type washing machine for controlling washing of laundry in such a manner as to detect generation of excessive foam by means of a drive current of a motor and reduce a rotational frequency of the rotatable drum (e.g., see PTL 3).

[0014] However, in the configurations of the conventional rotatable drum type washing machines, control is performed by detecting only generation of excessive foam, thus causing a problem of not being able to optimally clean the laundry based on the generated state of the foam.

[0015] DE 10 2007 036041 A1 relates to a method for eliminating foam in a drum washing machine with a program control for controlling a program sequence, one in a lye container rotatably mounted drum, a water inlet system, one at the bottom of the solution container arranged liquor drainage system with a lye pump, a drive motor for the drum and a sensor for determining a foam level hS and/or a negative temporal gradients of the foam level (dhS/dt) a in the tub located liquid-air mixture, wherein when the sensor is detected foam during a spin-up of the drum, ie; a continuous or discontinuous increasing the rotational speed of the drum, in continuously or intermittently switched liquor pump a small amount of water is added continuously or batchwise. DE 10 2007 036041 A1 also relates to a device suitable for carrying out this method drum washing machine.

[0016] EP 0 268 155 A2 describes a washing machine with a device for preventing the formation of foam. During the spinning operation, foam is often produced in the lye container for the washing drum after a spinning time of a few seconds from a mixture of water and washing agents which is expelled from the material being spun, and this can sometimes lead to an interruption of the work of the emptying pump. So that spinning can be carried out as soon as possible after completion of the washing operation at the maximum possible washing- drum speed of the material being washed or spun, without the danger of the formation of foam in the lye container to prevent the further pumping away of the washing lye, there is provided as a measuring device a pressure sensor, the output signals of which are an indication of the foam formation during the spinning operation, these output signals representing control variables for the drive motor of the washing drum and therefore for the regulation of the spinning speed. There is also described a program-controlled washing machine with a washing drum drivable in the washing and spinning mode by means of a motor.

[0017] EP 0 740 010 A2 describes a washing method which can eliminate suds or foam created in the course of washing by a washing machine and can effectively prevent the creation of foam, thereby improving the washing efficiency of the washing machine. In the washing method, a part of the washing liquid is continuously recirculated and sprayed during the washing process while the washing liquid is partially drained at each predetermined time interval. In the rinsing process, a part of the rinsing water is also continuously recirculated and sprayed during the rinsing process while the rinsing water is partially drained at each predetermined time interval.

Citation List

Patent Literature

[0018] 

PTL 1: Unexamined Japanese Patent Publication No. H8-299658

PTL 2: Unexamined Japanese Patent Publication No. 2003-260290

PTL 3: Unexamined Japanese Patent Publication No. 2005-169001

PTL 4: DE 10 2007 036041 A1

PTL 5: EP 0 268 155 A2

PTL 6: EP 0 740 010 A2

SUMMARY OF THE INVENTION

[0019] The invention is defined by the subject-matter of independent claim 1. The dependent claims are directed to advantageous embodiments.

ADVANTAGES OF THE INVENTION

[0020] Advantageously, a rotatable drum type washing machine includes: a rotatable drum for housing laundry; a vessel for housing the rotatable drum; a motor for driving the rotatable drum; a water supply unit for supplying washing and/or rinsing water into the vessel; a circulator for circulating the washing and/or rinsing water in the vessel into the rotatable drum; a foam detector for detecting an amount of foam; and a controller for controlling at least one of the following steps a washing step, a rinsing step and water removal step. The controller is configured to control so as to rotate the rotatable drum at a predetermined rotational frequency and configured to control a spraying of the washing and/or rinsing water by the circulator onto the laundry in the rotatable drum based on the amount of foam detected by the foam detector.

[0021] Therefore, based on the amount of foam detected by the foam detector, the rotatable drum is rotated at the predetermined rotational frequency, to discharge the washing and/or rinsing water impregnated among fibers of the laundry by centrifugal force together with dirt. Further, the washing and/or rinsing water is sprayed by the circulator onto the laundry in the rotatable drum, thereby loading (infiltrating) the washing and/or rinsing water into the fibers of the laundry. As a result, when there is much dirt on the laundry, replacement of the washing and/or rinsing
water among the fibers of the laundry is promoted to accelerate a dirt removing effect so as to enhance a cleaning effect.

[0022] Further, dirt attached to the detergent and to the washing and/or rinsing water mixed with the detergent in the vicinity of the laundry can be peeled as much as necessary. Therefore, unnecessary foaming at the time of washing is suppressed, and the cleaning operation is performed as much as necessary. This can result in realization of a rotatable drum type washing machine capable of reducing a wasteful operation and power consumption.

BRIEF DESCRIPTION OF DRAWINGS

[0023] 

FIG. 1 is a principal-part sectional view of a rotatable drum type washing machine in a first exemplary embodiment of the present invention.

FIG. 2 is a block diagram explaining control of the rotatable drum type washing machine according to the same exemplary embodiment.

FIG. 3 is a time chart explaining an example of a control operation of the rotatable drum type washing machine according to the same exemplary embodiment.

FIG. 4 is a view showing a state of laundry at the time of operating the rotatable drum type washing machine according to the same exemplary embodiment.

FIG. 5 is a time chart explaining an example of an operation of a rotatable drum type washing machine according to a second exemplary embodiment of the present invention.

FIG. 6 is a schematic constitutional view of a rotatable drum type washing machine according to a third exemplary embodiment of the present invention.

FIG. 7 is a flowchart explaining a control operation of a washing step of the rotatable drum type washing machine according to the same exemplary embodiment.

FIG. 8 is a diagram showing an example of an output of a transparency sensor in the washing step of the rotatable drum type washing machine according to the same exemplary embodiment.

FIG. 9A is a flowchart showing cleaning control of the rotatable drum type washing machine in a fourth exemplary embodiment of the present invention.

FIG. 9B is a flowchart showing cleaning control of the rotatable drum type washing machine in the same exemplary embodiment.

DESCRIPTION OF EMBODIMENTS

[0024] Embodiments of the present invention will be described below with reference to the drawings. It is to be noted that the present invention is not restricted by the present exemplary embodiments.

FIRST EXEMPLARY EMBODIMENT

[0025] FIG. 1 is a principal-part sectional view of a rotatable drum type washing machine in a first exemplary embodiment of the present invention. FIG. 2 is a block diagram explaining control of the rotatable drum type washing machine according to the same exemplary embodiment.

[0026] As shown in FIG. 1, the rotatable drum type washing machine of the present embodiment at least includes: vessel 2 (for example water tub) shakably disposed inside enclosure 1; rotatable drum 3 rotatably housed in vessel 2; motor 7 for rotatably driving rotatable drum 3; circulation channel 16 provided with circulation pump 17; controller 22; and foam detectors 27, 28. In enclosure 1, vessel 2 is disposed in the state of being inclined forward and elastically supported via an underslung spring (not shown) and a dumper (not shown), to store washing and/or rinsing water.

[0027] Rotatable drum 3 is formed in a bottom-closed cylinder shape for housing laundry and rotatably provided in vessel 2. A peripheral side wall surface of rotatable drum 3 is provided with a plurality of baffles 4 and a large number of small holes 5 communicating with the inside of vessel 2, and the front surface side of rotatable drum 3 is provided with opening 6 through which laundry is put in and taken out.

[0028] Motor 7 is fixed for example to the outer-peripheral lower part of vessel 2, and rotationally drives rotatable drum 3 via belt 8 and pulley 9. Water supply valve 10 is subjected to opening/closing-control by controller 22, and by opening water supply valve 10, washing and/or rinsing water is supplied into vessel 2 through detergent case 12 which is provided in water supply channel 11 and into which a detergent is inserted.

[0029] Further, on the bottom in vessel 2, water tank unit 13 for storing the washing and/or rinsing water is provided, and in water tank unit 13, heater 14 is disposed in substantially parallel (or parallel) with the water surface of the washing and/or rinsing water stored in vessel 2. Then, heater 14 heats the washing and/or rinsing water stored in water tank unit 13 to a predetermined temperature (e.g., 30 to 40°C) suitable for washing. At this time, the temperature of the washing and/or rinsing water in water tank unit 13 is detected by temperature detector 15 such as a thermister. For example, when there is no need for promoting foaming of the detergent by heating the washing and/or rinsing water, water tank unit 13 and heater 14 may not particularly be provided in vessel 2.

[0030] Moreover, the washing and/or rinsing water stored in water tank unit 13 in vessel 2 is circulated in rotatable drum 3 by circulation pump 17 as a circulator provided in circulation channel 16. At this time, one end of circulation channel 16 communicates with intake 18 which is provided on the bottom of water tank unit 13 and sucks in the washing and/or rinsing water, and the other end thereof communicates with outlet 19 which is provided in the upper part of opening 6 on the front surface side of rotatable drum 3. Then, the washing and/or rinsing water sucked in from intake 18 is spewed out inward rotatable drum 3 from outlet 19 and then circulated by circulation pump 17 provided in circulation channel 16.

[0031] Further, switch valve 20 is provided downstream of circulation pump 17 in circulation channel 16. Switch valve 20 selectively switches between circulation channel 16 that communicates with outlet 19 and drainage channel 21 that discharges the washing and/or rinsing water to the outside of the machine. Specifically, at the time of washing and rinsing, switch valve 20 is switched to the circulation channel 16 side, to spew out the washing and/or rinsing water in water tank unit 13 from outlet 19 toward the laundry in rotatable drum 3. On the other hand, after washing and rinsing, switch valve 20 is switched to the drainage channel 21 side, to discharge the washing and/or rinsing water in vessel 2 to the outside of the rotatable drum type washing machine.

[0032] Moreover, controller 22 is provided in enclosure 1, and as shown in FIG. 2, for example, operations of motor 7, water supply valve 10, heater 14, circulation pump 17, switch valve 20 and the like are controlled based on detection information (detection signals) of temperature detector 15, weight detector 25, water-level detector 26 and foam detector 27. Accordingly, a series of steps such as a washing step, a rinsing step and a water removal step is controlled by controller 22.

[0033] Further, as shown in FIG. 1, at least two foam detectors are provided at positions opposed to the rotatable drum on the inside of vessel 2. One foam detector 27 is provided at a lower position than the center of rotational shaft 3A of rotatable drum 3 on the inside of the front surface in vessel 2. It is to be noted that the reason for installing foam detector 27 at this position is to promptly detect generated foam. If foam detector 27 is installed at a higher position than the center of rotational shaft 3A of rotatable drum 3, detection of the amount of foam is delayed, and hence the inside of rotatable drum 3 is filled with foam due to generation of excessive foam. At this time, an operation such as a defoaming step or water drainage is performed for removing the filling foam. Thereat, in order to avoid those operations, foam detector 27 is provided at the lower position than the center of rotational shaft 3A of rotatable drum 3.

[0034] The other foam detector 28 is provided, for example, at a position opposed to the outer-peripheral bottom surface of rotatable drum 3 in the vicinity of the upper part of the rear-surface (motor) side in vessel 2. It is to be noted that foam detectors 27, 28 of the present exemplary embodiment are, for example, configured by an electrode sensor made up of a pair of electrodes, and an amount of foam is detected by controller 22 by means of a current change at the time of the foam coming into contact between the pair of electrodes. It is thereby possible to detect generation of foam up to a predetermined height at which foam detector 27 is provided in rotatable drum 3.

[0035] The rotatable drum type washing machine of the present exemplary embodiment is configured as described above.

[0036] An operation and function of the rotatable drum type washing machine will be described below with reference to FIGS. 3 and 4, while referring to FIGS. 1 and 2.

[0037] FIG. 3 is a time chart explaining an example of a control operation of the rotatable drum type washing machine according to the first exemplary embodiment. FIG. 4 is a view showing a state of laundry at the time of operating the rotatable drum type washing machine according to the same exemplary embodiment.

[0038] First, door 23 provided openably/closably on the front surface side of enclosure 1 shown in FIG. 1 is opened, and laundry is loaded into rotatable drum 3 from opening 6.

[0039] Next, a power supply switch (not shown) of operator 24 provided on the top surface of enclosure 1 is turned on, and a start switch (not shown) is operated, to start an operation of the rotatable drum type washing machine.

[0040] As shown in FIG. 3, controller 22 then detects an amount of loaded laundry by weight detector 25 shown in FIG. 2, to open water supply valve 10 and start supply of water into vessel 2 through detergent case 12, while rotatably driving rotatable drum 3 by motor 7 to be rotated forwardly, backwardly and the like at 50 rpm, for example. It is to be noted that an amount of water supplied is previously set in accordance with an amount of loaded cloths, is the amount being detected by weight detector 25. Thereby, washing and/or rinsing water is supplied into vessel 2 together with a detergent inserted into detergent case 12. When water-level detector 26 detects the previously set amount of washing and/or rinsing water supplied, controller 22 closes water supply valve 10 to halt supply of the washing and/or rinsing water.

[0041] Next, the washing step is performed.

[0042] In the washing step, as shown in FIG. 3, rotatable drum 3 is driven by motor 7 to be forwardly and backwardly rotated at 50 rpm, for example. Hence the so-called beat-washing is performed in which the laundry in rotatable drum 3 is lifted by baffles 4 and dropped from above onto the water surface of the washing and/or rinsing water in rotatable drum 3.

[0043] It should be noted that, when the temperature of the supplied washing and/or rinsing water is low or hot water is used for washing, heater 14 is turned on, to heat the washing and/or rinsing water in water tank unit 13 to a temperature suitable for washing, e.g., 30 to 40°C. This is preferable since, when cleaning performance deteriorates, for example at the time of a low temperature of not higher than 10°C, the cleaning effect can be enhanced by heating the washing and/or rinsing water.

[0044] At this time, the temperature of the washing and/or rinsing water heated by heater 14 is detected by temperature detector 15 such as a thermister provided on the outer bottom of water tank unit 13. Controller 22 then controls a current carrying amount of heater 14, or the like, such that the temperature of the washing and/or rinsing water becomes the previously set temperature.

[0045] Subsequently, controller 22 switches switch valve 20 to the circulation channel 16 side, and drives circulation pump 17 at a previously set rotational frequency, to circulate a predetermined amount of washing and/or rinsing water in rotatable drum 3. Thereby, the washing and/or rinsing water heated in water tank unit 13 is spewed out from outlet 19 and impregnated into the laundry that is agitated and beat-washed in rotatable drum 3. As a result, it is possible to promote dissolution of the detergent into the washing and/or rinsing water, while strengthening the function of separating dirt from clothes such as laundry, so as to enhance the clearing effect.

[0046] At this time, when the washing and/or rinsing water in water tank unit 13 is circulated by circulation pump 17 into rotatable drum 3, a water level in vessel 2 is lowered. For this reason, there occurs a case where the temperature of water tank unit 13 detected by temperature detector 15 exceeds a predetermined temperature (e.g. 70°C) due to lowering of the water level. In that case, controller 22 reduces the rotational frequency of circulation pump 17 to decrease an amount of washing and/or rinsing water circulated, to recover the water level in vessel 2.

[0047] Since the temperature of water tank unit 13 decreases with rise in water level in vessel 2, controller 22 controls heater 14 such that the temperature of washing and/or rinsing water in water tank unit 13 becomes a re-set temperature. Therefore, heater 14 is submerged into the risen washing and/or rinsing water, and controller 22 stably keeps the temperature of the washing and/or rinsing water in water tank unit 13 at the set temperature.

[0048] Hence the rotational frequency of circulation pump 17 and the like are controlled based on the temperature detected by temperature detector 15, thereby allowing heater 14 to be kept in the state of capable of heating the washing and/or rinsing water without being exposed on the water surface of the washing and/or rinsing water. Accordingly, the washing and/or rinsing water can be circulated by circulation pump 17 and supplied from outlet 19 into rotatable drum 3, while being heated to the optimum temperature.

[0049] Further, the washing and/or rinsing water in vessel 2 is rolled up and agitated by rotational driving of rotatable drum 3, to generate foam, the washing and/or rinsing water containing the detergent. When foam is excessively generated in vessel 2, it is detected by foam detector 27 disposed at a lower position than the center of rotational shaft 3A of rotatable drum 3. This can prevent a delay in detecting generated foam, while obviating filling of the inside of rotatable drum 3 with foam, to avoid the steps such as the defoaming step, the water drainage and the like. This can result in efficient washing of laundry.

[0050] On the other hand, foam detector 28 provided in the upper part of the rear surface side in vessel 2 detects generated foam when the foam is not detected by foam detector 27 and generated in a large amount up to the upper portion in vessel 2. This prevents the generated foam from reversely flowing into the detergent case and being leaked to the outside of the rotatable drum type washing machine.

[0051] At this time, as shown in FIG. 3, foam detectors 27, 28 each detect an amount of foam generated in vessel 2 at the time when the washing and/or rinsing water containing detergent is agitated by rotation of rotatable drum 3 after closing water supply valve 10 and completing supply of the washing and/or rinsing water. It is to be noted that foam detectors 27, 28 each include for example the electrode sensor and detects a current generated by foam coming into contact with the electrode sensor. A value of the detected current is then measured, to judge generation of foam and an amount of foam.

[0052] There will be described below a method for controlling rotatable drum type washing based on a result of detection by the foam detector of the present exemplary embodiment.

[0053] First, as shown in FIG. 3, controller 22 forwardly and backwardly rotates rotatable drum 3 at 50 rpm for a predetermined time to dissolve the detergent into the washing and/or rinsing water, and thereafter turns on foam detector 27 for a predetermined time to detect an amount of foam in vessel 2.

[0054] Generally, an appropriate amount of detergent is inserted into washing and/or rinsing water set in accordance with an amount of laundry, and dissolved into the washing and/or rinsing water. The dissolved detergent is foamed by rotation of rotatable drum 3 and the like so as to be activated, thus enhancing performance of removing dirt on the laundry. However, when there is much dirt on the laundry, a little foam is generated, to decrease the degree of activation of the detergent.

[0055] That is, when the foam generated in vessel 2 does not reach foam detector 27 and the foam is thus not detected, namely when the amount of foam is determined to be small, there is judged to be much dirt on the laundry in rotatable drum 3.

[0056] Thereat, when there is judged to be much dirt on the laundry, controller 22 controls a rotational frequency of motor 7, and increases the rotational frequency of rotatable drum 3 up to 150 to 200 rpm, to drive rotatable drum 3 to be rotated at high speed. At this time, the laundry is attached to the inner surface of rotatable drum 3 by high-speed rotation of rotatable drum 3. Hence the washing and/or rinsing water impregnated among the fibers of the laundry is discharged by centrifugal force together with dirt. Simultaneously, as shown in FIG. 3, circulation pump 17 as the circulator is turned on, to circulate the washing and/or rinsing water in water tank unit 13 into rotatable drum 3 and spray it onto the laundry in a shower form, for example.

[0057] Accordingly, as shown in FIG. 4, for example when rotatable drum 3 is rotated in a direction of an arrow BB, laundry 33 is rotated by centrifugal force in such a state as to stick to the inner surface of rotatable drum 3. At this time, the washing and/or rinsing water is exchanged frequently among fibers of laundry 33. This results in constant loading of new washing and/or rinsing water into the fibers of laundry 33, thus allowing enhancement of the clearing effect of laundry 33. Further, the washing and/or rinsing water can be sprayed onto the laundry by simultaneous circulation of the washing and/or rinsing water in rotatable drum 3, thus accelerating replacement of the washing and/or rinsing water among fibers of laundry 33. This can result in further enhancement of the cleaning effect of the laundry.

[0058] In the above manner, the amount of foam in vessel 2 is detected to control the rotational frequency of the rotatable drum, thereby executing the washing step.

[0059] The rinsing step is then started after completion of the washing step. Also in the rinsing step, similarly, switch valve 20 is first switched to the drainage channel 21 side, to discharge the washing and/or rinsing water in vessel 2, and switch valve 20 is then switched to the circulation channel 16 side. Subsequently, water supply valve 10 is opened and water supply is started from water supply channel 11 through detergent case 12, and a predetermined amount of rinsing water is supplied into vessel 2.

[0060] Next, when water-level detector 26 detects a previously set predetermined water level, controller 22 closes water supply valve 10 to halt supply of the rinsing water, and rotationally drives motor 7. At this time, in the rinsing step, rotatable drum 3 is driven by motor 7 to be forwardly and backwardly rotated at 50 rpm, and the laundry in rotatable drum 3 is lifted and dropped onto the surface of the rinsing water.

[0061] Also in the rinsing step, similarly to the washing step, heater 14 provided in water tank unit 13 of vessel 2 may be turned on to heat the rinsing water in vessel 2 so as to perform rinsing. Further, also in the rinsing step, switch valve 20 may be switched to the circulation channel 16 side to operate circulation pump 17 and circulate the rinsing water into rotatable drum 3. Hence a detergent component and remaining dirt are quickly removed from laundry such as clothes, thereby allowing enhancement of the rinsing effect.

[0062] As described above, according to the present exemplary embodiment, the rotatable drum is rotated at a predetermined rotational frequency based on the amount of foam detected by the foam detector and the washing and/or rinsing water is sprayed by the circulator onto the laundry in the rotatable drum, whereby it is possible to frequently exchange the washing and/or rinsing water among the fibers of the laundry by centrifugal force. Hence new washing and/or rinsing water can be constantly loaded into the fibers of the laundry, and simultaneously, the washing and/or rinsing water can be circulated in rotatable drum 3, to spray (scatter) the washing and/or rinsing water onto the laundry. As a result, replacement of the washing and/or rinsing water among the fibers of the laundry is accelerated, thereby allowing enhancement of the cleaning effect.

SECOND EXEMPLARY EMBODIMENT

[0063] A rotatable drum type washing machine in a second exemplary embodiment of the present invention will be described below with reference to FIG. 5.

[0064] FIG. 5 is a time chart explaining an example of an operation of the rotatable drum type washing machine according to the second exemplary embodiment of the present invention.

[0065] That is, as shown in FIG. 5, the rotatable drum type washing machine of the present exemplary embodiment is different from the rotatable drum type washing machine of the first exemplary embodiment in that upon rotating the rotatable drum at a predetermined rotational frequency at which the laundry sticks to the inner surface of the rotatable drum, at the start of the washing step, the washing and/or rinsing water is supplied and thereafter an amount of foam by foam detector 27 is detected. The other configurations and operations are the same as those in the first exemplary embodiment, and hence specific descriptions thereof may be omitted.

[0066] Accordingly, the washing step different from that in the first exemplary embodiment will be described below with reference to FIG. 5, while referring to FIG. 1.

[0067] As shown in FIG. 5, first at the start of the washing step, the rotational frequency of rotatable drum 3 is increased by motor 7 up to 150 to 200 rpm, for example, and that rotational frequency is kept. At this time, since vessel 2 has not been supplied with the washing and/or rinsing water, the laundry loaded in vessel 2 (for example water tub) is in a dry state. Accordingly, even when rotatable drum 3 is rotated at a high speed, the laundry in rotatable drum 3 tends not to get unbalanced and there is a little vibration in rotatable drum 3 due to eccentricity. Hence it is possible to smoothly increase the rotational frequency of rotatable drum 3 up to a predetermined rotational frequency.

[0068] After the rotational frequency of rotatable drum 3 has been increased up to 150 to 200 rpm and the rotation of rotatable drum 3 has been stabilized, water supply valve 10 is opened and a predetermined amount of washing and/or rinsing water is supplied into vessel 2. The washing and/or rinsing water supplied into vessel 2 is gradually impregnated into the laundry that is rotated in the state of sticking to the inner surface of rotatable drum 3. For this reason, rotatable drum 3 can keep high-speed rotation in a stable state without getting the laundry unbalanced in rotatable drum 3.

[0069] The washing and/or rinsing water supplied into vessel 2 is agitated by high-speed rotation of rotatable drum 3, thereby dissolving the detergent contained in the washing and/or rinsing water while foam is generated

[0070] Then, with the lapse of agitating time, the foam generated in vessel 2 rises in rotatable drum 3 as its amount increases, and reaches foam detector 27 to be detected thereby.

[0071] At this time, the washing and/or rinsing water is supplied into vessel 2 in the state of rotatable drum 3 being rotated at a high speed until time T1 at which the predetermined amount of washing and/or rinsing water is supplied. During this period, the washing and/or rinsing water containing the detergent is sufficiently agitated and foam in accordance with dirt is generated.

[0072] Then, at the time when supply of the washing and/or rinsing water is completed after the lapse of time T1 from the start of supply of the water and the washing and/or rinsing water containing the detergent has been sufficiently agitated, the foam is detected by foam detector 27. At this time, when the foam does not reach foam detector 27 and is not detected, namely when the amount of foam is small, there can be judged to be much dirt on the laundry in rotatable drum 3.

[0073] Then, when there is judged to be much dirt on the laundry, controller 22 keeps the rotational frequency of rotatable drum 3 at 150 to 200 rpm, to rotate the rotatable drum at a rotational frequency at which the laundry sticks to the inner surface of rotatable drum 3. Hence the washing and/or rinsing water impregnated among the fibers of the laundry is discharged by centrifugal force together with dirt.

[0074] Simultaneously, controller 22 drives circulation pump 17 as the circulator, to circulate the washing and/or rinsing water and spray it onto the laundry in rotatable drum 3. Hence it is possible to effectively load the washing and/or rinsing water into the fibers of the laundry. That is, when there is much dirt on the laundry, the washing and/or rinsing water is actively replaced among the fibers of the laundry to accelerate removal of the dirt, thereby allowing enhancement of the clearing effect.

[0075] According to the present exemplary embodiment, the rotatable drum is rotated at a high speed from the start of the washing step, to sufficiently roll up and agitate the washing and/or rinsing water in the vessel, and hence it is possible to promote dissolution of the detergent and generation of foam. This can result in accurate detection of the amount of foam.

THIRD EXEMPLARY EMBODIMENT

[0076] A rotatable drum type washing machine in a third exemplary embodiment of the present invention will be described below with reference to FIG. 6.

[0077] FIG. 6 is a schematic constitutional view of the rotatable drum type washing machine according to the third exemplary embodiment of the present invention. It is to be noted that in the third exemplary embodiment, a description will be given using as an example a different type of rotatable drum type washing machine from the rotatable drum type washing machine of the first exemplary embodiment, but basic configurations and operations are the same as those in the first exemplary embodiment.

[0078] That is, as shown in FIG. 6, the rotatable drum type washing machine of the present exemplary embodiment is different from the rotatable drum type washing machine of the first exemplary embodiment in that a transparency sensor for detecting a transparency (turbidity) of washing and/or rinsing water is as the foam detector, the heater is not provided, and the like. Since the method for control by detecting the amount of foam in the rotatable drum by the foam detector will thus be different, an exemplary embodiment will be provided and described below. As shown in FIG. 6, the rotatable drum type washing machine of the present exemplary embodiment at least includes: vessel 2 (for example water tub) shakably disposed inside enclosure 1; rotatable drum 3 rotatably housed in vessel 2; motor 7 for rotatably driving rotatable drum 3; circulation channel 16 provided with circulation pump 17; controller 22; and foam detector 32. Rotatable drum 3 is disposed as inclined downward from a horizontal direction to a rear surface direction. Further, rotatable drum 3 is connected with rotational shaft 3A of motor 7 provided on the rear surface of rotatable drum 3, and rotationally driven by rotation of motor 7 through rotational shaft 3A. The peripheral side wall surface of rotatable drum 3 is provided with a large number of small holes (not shown), and rotatable drum 3 functions as a water removal vessel and a drying vessel as well as a washing vessel.

[0079] Further, intake 18 is provided in the vicinity of the lowest part of vessel 2, and communicates with circulation channel 16. Then, as shown in arrows in the figure, washing and/or rinsing water taken from intake 18 by circulation pump 17 provided in circulation channel 16 is circulated as spewed out in the shower form from outlet 30, which is provided for example in the lower part of the front surface side of rotatable drum 3, into rotatable drum 3 through circulation channel 16. Therefore, circulation of the washing and/or rinsing water through circulation channel 16 can be performed only by control of circulation pump 17. As a result, the washing and/or rinsing water can be circulated regardless of cleaning control which is to control the detergency, such as a water flow of the washing and/or rinsing water in rotatable drum 3 which is generated by rotation of rotatable drum 3.

[0080] At this time, foreign matters such as fibers of the laundry and hair included in the washing and/or rinsing water as circulation water at the time of circulation are removed by installing filter 31 between intake 18 and circulation pump 17 in circulation channel 16. This can obviate clogging of circulation pump 17 and drainage channel 21.

[0081] Further, the transparency sensor that functions as foam detector 32 is provided upstream of filter 31 in circulation channel 16. Transparency sensor is configured by a light-emitting element such as an LED (Light Emitting Diode) and a light-receiving element such as a photo transistor which are provided as opposed to each other. At this time, at least a portion of circulation channel 16 located between the light-emitting element and the light-receiving element of the transparency sensor is configured by a translucent material.

[0082] Then, light emitted from the light-emitting element of the transparency sensor is transmitted through the washing and/or rinsing water flowing through circulation channel 16 and received by the light-receiving element. An amount of light received is converted into a voltage and then outputted to controller 22. Thereby, an amount of foam is detected by the turbidity of the washing and/or rinsing water. Further, the turbidity is found from the output voltage of the transparency sensor.

[0083] Moreover, switch valve 20 is provided for example between intake 18 and circulation pump 17, and connected to drainage channel 21 located downstream of switch valve 20.

[0084] Furthermore, water-level detector 26 is provided in the vicinity of intake 18 of vessel 2 which is impregnated (submerged) into the washing and/or rinsing water immediately after its supply, and detects a water level of the water supplied into vessel 2 and rotatable drum 3. Water-level detector 26 is configured for example by a diaphragm or the like, and detects pressure applied to the diaphragm as a transformation of the film, to detect the water level. It is to be noted that an amount of diaphragm transformed in water-level detector 26 is detected for example by a change in capacitance or a distortion gauge.

[0085] Further, water supply inlet 29 is connected to an external faucet through a hose (not shown) or the like, and sequentially supplies washing and/or rinsing water and rinsing water into vessel 2 and rotatable drum 3 by opening/closing of water supply valve 10.

[0086] Moreover, controller 22 is, configured for example by a microcomputer or the like, and when a water level detection signal of water-level detector 26 is inputted, opening/closing of switch valve 20 and water supply valve 10, motor 7 and circulation pump 17 are controlled, to control all of the washing step.

[0087] Furthermore, controller 22 converts the output voltage of the light-receiving element constituting the transparency sensor as foam detector 32 into a transparency of the washing and/or rinsing water, to perform an input step. At this time, the higher the transparency is, namely the smaller the amount of foam is, the lower the output voltage of the light-receiving element becomes. On the other hand, when the amount of foam of the washing and/or rinsing water passing through circulation channel 16 increases, the transparency decreases, and hence the output voltage of the light-receiving element increases. That is, the amount of foam of the washing and/or rinsing water can be detected by the output voltage of the transparency sensor which is outputted based on the transparency of the washing and/or rinsing water.

[0088] Further, controller 22 also has a function of a cloth-amount detector by detecting a current signal flowing through motor 7 that rotates rotatable drum 3. Thereby, a weight of rotatable drum 3, namely a weight of laundry loaded into rotatable drum 3 is determined, to adjust an amount of water, washing time and the like to the optimum.

[0089] An operation of the rotatable drum type washing machine according to the present exemplary embodiment will be described below with reference to FIG. 7.

[0090] FIG. 7 is a flowchart explaining the control operation of the washing step of the rotatable drum type washing machine according to the third exemplary embodiment of the present invention.

[0091] First, when laundry is loaded into the rotatable drum and washing is started, controller 22 detects an amount of laundry by the cloth-amount detector (Step S1). In addition, as described above, the cloth-amount detector detects an amount of cloths based on at least one piece of information concerning the motor operation, such as a magnitude of a load current signal of motor 7, changes in current amount and rotational angle at the time of rotating rotatable drum 3 together with the laundry.

[0092] Next, controller 22 decides a basic amount of washing and/or rinsing water to be supplied based on the amount of laundry detected by the cloth-amount detector, the washing and/or rinsing water being supplied into vessel 2. For example, when the amount of laundry is determined as "small", controller 22 sets WL1 (Water Level 1) of a "low" water level as a set water level. When the amount of laundry is determined as "medium", controller 22 sets WL2 of a "medium" water level as the set water level. Further, when the amount of laundry is determined as "large", controller 22 sets WL3 of a "high" water level as the set water level (Step S2).

[0093] Next, controller 22 opens water supply valve 10 (Step S3), and supplies the washing and/or rinsing water into vessel 2 and rotatable drum 3 until the water reaches the set water level (Step S4). When the washing and/or rinsing water does not reach the set water level (NO in Step S4), the detection operation is repeated until the washing and/or rinsing water reaches the set water level. At this time, controller 22 drives circulation pump 17 during supply of the washing and/or rinsing water, and circulates the washing and/or rinsing water supplied as circulation water together with the detergent from outlet 30 into vessel 2 through circulation channel 16, to promote dissolution of the detergent into the washing and/or rinsing water. It is to be noted that, when the washing and/or rinsing water is spewed out from outlet 30 into rotatable drum 3, clothes as laundry absorb the washing and/or rinsing water before the detergent is dissolved into the washing and/or rinsing water. Thereat, the rotational frequency of circulation pump 17 is set to be weak (low), to control such that much washing and/or rinsing water is not spewed out into rotatable drum 3.

[0094] Next, when water-level detector 26 detects that the set water level has been reached (YES in Step S4), controller 22 closes water supply valve 10 (Step S5).

[0095] A water supply step S1A is executed by Steps S1 to S5 described above.

[0096] Next, controller 22 starts a first low-speed agitating step for rotationally driving rotatable drum 3 at a predetermined rotational frequency (Step S6). It should be noted that the first low-speed agitating step is the agitating operation of lifting the laundry by the baffles or the like in rotatable drum 3 and dropping the laundry from the upper part of rotatable drum 3 due to its deadweight. That is, rotatable drum 3 is rotationally operated at a rotational frequency to such an extent that the laundry does not stick to the inner peripheral wall surface of rotatable drum 3 by centrifugal force, for example at the order of 50 rpm or lower, though depending also on the amount of laundry water. At this time, rotatable drum 3 may be rotated in the same one direction or may be periodically rotated in the reverse direction. Thereby, kinetic energy at the time of dropping is applied to the laundry, to allow effective cleaning of the laundry.

[0097] Then, simultaneously with the first low-speed agitating step, controller 22 turns on circulation pump 17 to drive it for example for the order of one minute, and circulates the washing and/or rinsing water with the detergent sufficiently dissolved therein from outlet 30 into rotatable drum 3 through circulation channel 16 (Step S7). This proceeds impregnation of the washing and/or rinsing water into the laundry. It is to be noted that circulation pump 17 is driven at a rotational frequency at which the washing and/or rinsing water sufficiently is spewed out into rotatable drum 3 and easily impregnated into the laundry.

[0098] Next, controller 22 turns off and halts circulation pump 17 (Step S8). Thereby, the washing and/or rinsing water is brought into the state of not being circulated through circulation channel 16 for example for the order of one minute, and retained in rotatable drum 3 and vessel 2 in order to remove foam having generated during the circulation.

[0099] Next, controller 22 again activates circulation pump 17 for example after the lapse of the order of one minute from the halting of circulation pump 17 (Step S9). Accordingly, the washing and/or rinsing water is again circulated as spewed out from outlet 30 into rotatable drum 3 through circulation channel 16.

[0100] Then at the re-activation of circulation pump 17, controller 22 reads an output voltage from the transparency sensor to detect a transparency of the washing and/or rinsing water. At this time, controller 22 determines an amount of foam of the washing and/or rinsing water from the output voltage as the read transparency (Step S10).

[0101] Here, the detection operation of the transparency sensor for determining the amount of foam of the washing and/or rinsing water will be described below with reference to FIG. 8.

[0102] FIG. 8 is a diagram showing an example of the output voltage of the transparency sensor in the washing step of the rotatable drum type washing machine according to the third exemplary embodiment of the present invention. It is to be noted that FIG. 8 is one obtained by monitoring the output voltage of the transparency sensor from the start of cleaning, for example.

[0103] As shown in FIG. 8, when circulation pump 17 is turned on (Step S7) simultaneously with the first low-speed agitating step (Step S6) after completion of supply of the water, the washing and/or rinsing water with the detergent dissolved therein is spewed out from outlet 30 into rotatable drum 3 in the shower form through circulation channel 16. This leads to generation of foam by the detergent. At this time, due to generation of the foam, the output voltage of the transparency sensor abruptly increases (Z1), and when a certain period of time (not longer than one minute) elapses, the output voltage of the transparency sensor is settled at a stable value (Z2).

[0104] Then, when circulation pump 17 is turned off and halted after the lapse of one minute from the start of driving of circulation pump 17 (Step S8), circulation of the washing and/or rinsing water through circulation channel 16 stops. In this case, since the generated foam is retained in rotatable drum 3 or vessel 2 apart from intake 18 of circulation channel 16 which is located at a lower position than the water surface of the washing and/or rinsing water in vessel 2, the transparency of the washing and/or rinsing water in the vicinity of intake 18 increases. For this reason, the output voltage of the transparency sensor gradually decreases (Z3), and when a certain period of time (not longer than one minute) elapses, the output voltage of the transparency sensor is settled at a stable value (Z4).

[0105] At this time, since agitating is kept being performed in rotatable drum 3 for two minutes when circulation pump 17 is turned on and off, impregnation of the washing and/or rinsing water into the laundry is promoted, and dirt on the laundry comes up. It is to be noted that, although foam is generated by agitating of the washing and/or rinsing water and the laundry by rotation of rotatable drum 3, the more dirt the laundry has, the less foam tends to be generated because a larger amount of detergent component is consumed.

[0106] Moreover, as shown in FIG. 8, after the lapse of one minute from the halting of circulation pump 17, circulation pump 17 is turned back on (Step S9). Thereby, the foam retained on the water surface of the washing and/or rinsing water in rotatable drum 3 and vessel 2 is sucked from intake 18 into circulation channel 16 together with the washing and/or rinsing water. At this time, when there is a little dirt on the laundry or the amount of detergent is excessively large with respect to the dirt, excessive foam is generated for two minutes from the start of cleaning, and much foam having been generated passes through circulation channel 16.

[0107] At this time, after a predetermined time T0 (e.g., ten seconds) since driving of circulation pump 17 has been resumed, the output voltage (Z5) of the transparency sensor is detected, to determine an amount of foam.

[0108] At this time, as shown in FIGS. 7 and 8, when a value of the output voltage of the transparency sensor is a predetermined value, e.g. a value smaller than 4.5 V (YES in Step S10), the amount of foam is determined to be not larger than estimated.

[0109] Next, after determination of the amount of foam, standby is performed until a set time is reached (NO in Step S11). When the set time elapses (YES in Step S11), controller 22 controls driving of motor 7, to execute a high-speed rotation step for rotating rotatable drum 3 at a high speed (Step S12). At this time, the rotational frequency of rotatable drum 3 in the high-speed rotation step is a rotational frequency at which the laundry sticks to the inner wall surface of rotatable drum 3. Specifically, it is a rotational frequency that is high enough to allow moisture of the laundry in rotatable drum 3 to be forcibly removed by centrifugal force, e.g., preferably not lower than 150 rpm and further preferably not lower than 300 rpm. Moreover, the time T when rotatable drum 3 is rotated at a high speed is set relatively short, e.g., for 30 seconds so long as the washing and/or rinsing water contained in the laundry can be rinsed for the time T. It is to be noted that the high-speed rotation step may be performed by a successive one operation, or may be performed by an intermittent repeated on/off operation for a short period of time. At this time, since excessive foam may be generated by the detergent by high-speed rotation of rotatable drum 3, in the case of repeated operation, it is preferable to intermittently perform high-speed rotation.

[0110] Thereby, at the time of the first low-speed agitating step, the washing and/or rinsing water in the vicinity of fibers of clothes which contain the detergent made of a surfactant attached to a dirt substance of the fibers of the clothes is removed by centrifugal force by high-speed rotation of rotatable drum 3, thus allowing efficient removal of the dirt substance from the fibers of the clothes together with the washing and/or rinsing water. Further, during high-speed rotation of rotatable drum 3, the washing and/or rinsing water is circulated by circulation pump 17 and spewed out in the shower form toward the laundry in rotatable drum 3, thus allowing effective absorption of the washing and/or rinsing water not attached with dirt into the laundry. This promotes replacement of the washing and/or rinsing water included in the fibers of the clothes, to allow effective cleaning of the laundry.

[0111] Next, when the time T for the high-speed rotation step is not longer than 30 seconds (NO in Step S12), standby is performed until 30 seconds elapse and the high-speed rotation of rotatable drum 3 is kept.

[0112] Subsequently, when 30 seconds elapse as the time T for the high-speed rotation step (YES in Step S12), controller 22 carries out a second low-speed rotation step (Step S13). Similarly to the first low-speed agitating step in Step S6, in the second low-speed agitating step, circulation pump 17 is activated and the washing and/or rinsing water is spewed out from outlet 30 into rotatable drum 3 through circulation channel 16. At this time, rotatable drum 3 is rotated at a rotational frequency to such an extent that the laundry does not stick but rolls over in rotatable drum 3, e.g., 30 rpm. It is to be noted that circulation pump 17 may be continuously operated or intermittently operated, to discharge the washing and/or rinsing water from outlet 30 into rotatable drum 3.

[0113] That is, the second low-speed agitating step is further performed after the high-speed rotation step, thus allowing further peeling of the remaining dirt substance on the fibers of the clothes again by the chemical function of the detergent and the mechanical function associated with rotation of rotatable drum 3. At this time, when a concentration of the dirt substance in the washing and/or rinsing water among the fibers of the clothes is high, the dirt might be attached to the fibers of the clothes again. However, the dirt attached to the surfactant of the detergent and surrounded generally tends not to be attached again, and only a surfactant not attached to dirt is attached to the laundry. Hence it is possible to peel the dirt substance only with respect to the remaining dirt by the chemical function by the detergent.

[0114] Next, it is determined whether or not the second low-speed agitating step has been executed for a predetermined time (Step S14). When the second low-speed agitating step has not been executed for the predetermined time (NO in Step S14), standby is performed until the predetermined time has elapsed. At this time, the time for executing the second low-speed agitating step may be long enough when the remaining detergent is sufficiently impregnated into the laundry, and hence a predetermined time not depending on an amount of cloths is set, e.g., 5.5 minutes in the present exemplary embodiment.

[0115] Then, after execution of the second low-speed agitating step for the predetermined time (YES in Step S14), the washing step is completed. This can reduce a step using calculation processing or a constant table for controlling the washing step, so as to alleviate a load required for the step of controller 22.

[0116] On the other hand, when the output voltage of the transparency sensor is larger than a predetermined value (e.g., output value is not smaller than 4.5 V) (NO in Step S10), controller 22 determines that the amount of foam generated in rotatable drum 3 is excessive. In that case, the step does not move to the high-speed rotation step of Step S12 but the first low-speed agitating step of Step S6 is continued, and after the lapse of a predetermined time (e.g., 5.5 minutes) (Step S14), the washing step is completed.

[0117] It is to be noted that, although not described in FIG. 7, when the output voltage of the transparency sensor is far larger than the predetermined value in Step S10 (e.g., not smaller than 4.8 V), the washing step may be suspended, and the defoaming step may be provided in which part of the washing and/or rinsing water in vessel 2 is discharged to discharge foam and the washing and/or rinsing water is again supplied as much as necessary, to erase foam. Hence an influence on the cleaning performance exerted by generation of excessive foam can be made small.

[0118] As described above, according to the present exemplary embodiment, when the output voltage of the transparency sensor becomes not smaller than a predetermined value in a predetermined time during the washing step, the generated foam is judged to be much since dirt on the laundry is far below the detergency of the detergent. Then, the cleaning is completed without performing the high-speed rotation step. It is thereby possible to realize a rotatable drum type washing machine capable of suppressing a wasteful cleaning operation and power consumption.

[0119] It is to be noted that in the present exemplary embodiment, the description has been given using the example where controller 22 reads the output voltage of the transparency sensor after the predetermined time (10 seconds after re-activation of circulation pump 17), to determine the amount of foam, but this is not restrictive. For example, the output voltage of the transparency sensor may be read periodically or constantly during the time from Step S6 to Step S12 where rotatable drum 3 is rotated at a high speed, namely during the time set in Step S11. Hence it is possible to determine whether or not to perform the high-speed rotation step at the time when the output voltage of the transparency sensor becomes not smaller than the predetermined value. Therefore, for example in the case of using such a material that is, for a type of a laundry, foamed after a predetermined time (10 seconds) detected by the transparency sensor, even if much foam is generated after the predetermined time, cleaning can be completed without performing a high-speed rotation step for further foaming. This can result in further suppression of a wasteful cleaning operation and power consumption.

[0120] Moreover, in the present exemplary embodiment, the description has been given using the example where the output voltage of the transparency sensor is read to determine the amount of foam, but this is not restrictive. For example, a foam detection water-level sensor for detecting an amount of foam may be used. It should be noted that in the foam detection water-level sensor, for example, electrodes may be installed at two places. One place is on the wall surface of vessel 2 which is located in the vicinity of intake 18 and submerged into the water without fail at the time of performing the washing step, and the other place is on the wall surface of vessel 2 which is submerged into the water when a predetermined amount of washing and/or rinsing water is supplied and foam is generated in an amount not smaller than estimated. The foam detection water-level sensor may detect a change in resistance value between those electrodes. Accordingly, even when the turbidity of the washing and/or rinsing water itself becomes high due to dissolution of dirt on the laundry thereinto regardless of an amount of foam, it is possible to detect the amount of foam itself regardless of the transparency of the washing and/or rinsing water. This can result in determination of the amount of foam regardless of the kind of dirt. Similarly, the foam detector made of the electrode sensor configured by a pair of electrodes may be provided and the amount of foam may be detected, the electrode sensor having been described in the first exemplary embodiment.

[0121] Further, in the present exemplary embodiment, the description has been given using the example where the control is performed by the controller configured by the microcomputer, but this is not restrictive. For example, the control may be carried out in the form of a program cooperated with a hardware resource such as an electric/information appliance, a computer or a server which is provided with a CPU (or a microcomputer), a RAM, a ROM, a storage/record device, an I/O or the like. Accordingly, it is possible to easily install and control distribution, updating and the like of a new function by a program being recorded in a record medium such as a magnetic medium and optical medium or being delivered by use of a communication line such an the Internet.

FOURTH EXEMPLARY EMBODIMENT

[0122] A rotatable drum type washing machine in a fourth exemplary embodiment of the present invention will be described below with reference to FIGS. 9A and 9B. It is to be noted that, since the rotatable drum type washing machine of the fourth exemplary embodiment has the same configuration as that of the rotatable drum type washing machine described in the third exemplary embodiment, a detailed description thereof will be omitted.

[0123] FIGS. 9A and 9B are flowcharts showing cleaning control of the rotatable drum type washing machine in the fourth exemplary embodiment of the present invention.

[0124] The rotatable drum type washing machine of the present exemplary embodiment is different from that of the third exemplary embodiment in that, when the output voltage of the transparency sensor becomes not smaller than a predetermined value, controller 22 performs control by at least either reducing the rotational frequency of rotatable drum 3 in the high-speed rotation step or reducing the time for the high-speed rotation step. The other control method is similar to that of the third exemplary embodiment up to Step S9 shown in FIGS. 9A and 9B.

[0125] Thereat, the control after Step S15, which is different from that in the third exemplary embodiment, will be principally described.

[0126] As shown in FIGS. 9A and 9B, similarly to the third exemplary embodiment, for example after the lapse of the order of one minute from the halting of circulation pump 17 after execution of Step S1A for supplying water to Step S8, controller 22 again activates circulation pump 17 (Step S9).

[0127] Then, controller 22 reads the output voltage from the transparency sensor to detect the transparency of the washing and/or rinsing water. Controller 22 then determines an amount of foam of the washing and/or rinsing water from the output voltage as the read transparency (Step S15).

[0128] At this time, when the output voltage of the transparency sensor is smaller than 4.0 V (YES in Step S15), the amount of foam is judged to be normal. Standby is then performed until a set time elapses (NO in Step S16), and after the lapse of the set time (YES in Step S16), the high-speed rotation step is executed (Step S17). The high-speed rotation step is executed by rotating rotatable drum 3 at 300 rpm for 30 seconds, for example.

[0129] On the other hand, when the output voltage of the transparency sensor is not smaller than 4.0 V (NO in Step S15), it is determined whether or not the output voltage of the transparency sensor is not smaller than 4.5 V (Step S18).

[0130] At this time, when the output voltage of the transparency sensor is smaller than 4.5 V (YES in Step S18), the amount of foam is judged to be excessive. Standby is then performed until a set time elapses (NO in Step S19), and after the lapse of the set time (YES in Step S19), the high-speed rotation step is executed (Step S20). In this case, the rotational frequency of rotatable drum 3 is reduced as compared with the case where the output value of the transparency sensor is smaller than the predetermined value (4.0 V) in Step S15, and the high-speed rotation step is executed at 150 rpm for 30 seconds, for example.

[0131] Further, when the output voltage of the transparency sensor is not smaller than 4.5 V (NO in Step S18), it is determined whether or not the output voltage of the transparency sensor is not smaller than 4.8 V (Step S21) as shown in FIG. 9B. When the output voltage of the transparency sensor is smaller than 4.8 V (YES in Step S21), standby is performed until a set time elapses (NO in Step S22), and after the lapse of the set time (YES in Step S22), the high-speed rotation step is executed (Step S23). In this case, the time for rotating rotatable drum 3 is reduced as compared with the case where the output voltage value of the transparency sensor is smaller than the predetermined value (4.5 V) in Step S18, and the high-speed rotation step is executed at 150 rpm for 15 seconds, for example.

[0132] On the other hand, when the output voltage of the transparency sensor is not smaller than 4.8 V (NO in Step S21), the first low-speed agitating step of Step S6 is continued without performing the high-speed rotation step, and after the lapse of a predetermined time (YES in Step S24), the washing step is completed.

[0133] It should be noted that in the present exemplary embodiment, the description has been given using the example where reduction in rotational frequency in the high-speed rotation step and reduction in time therefor are simultaneously performed in accordance with the value of the output voltage of the transparency sensor, but this is not restrictive. For example, either the reduction of the rotatable drum in rotational frequency in the high-speed rotation step or the reduction of the rotatable drum in time for the high-speed rotation step may be executed. That is, when the amount of generated foam is large since dirt on the laundry is below the detergency of the amount of detergent inserted, it can be assumed that there is a little dirt to be peeled from the laundry. Therefore, even one of reduction in rotational frequency of the rotatable drum in the high-speed rotation step or reduction in for the high-speed rotation step is executed, sufficient cleaning performance can be obtained. This can result in realization of a rotatable drum type washing machine which can further suppress a wasteful cleaning operation and power consumption.

[0134] It is to be noted that, although the description has been given using the rotatable drum type washing machine as the example in each of the above exemplary embodiments, this is not restrictive, and for example, a rotatable drum type washing/drying machine may be applied, and a similar effect can be obtained.

[0135] Further, in each of the above exemplary embodiments 3 and 4, the descriptions have been given by use of the example of performing the low-speed agitating step twice, but this is not restrictive. For example, the low-speed agitating step may be performed just once. This leads to reduction in washing time.

[0136] The rotatable drum type washing machine of the present invention includes: a rotatable drum for housing laundry; a vessel for housing the rotatable drum; a motor for driving the rotatable drum; a water supply unit for supplying washing and/or rinsing water into the vessel; a circulator for circulating the washing and/or rinsing water in the vessel into the rotatable drum; a foam detector for detecting an amount of foam; and a controller for controlling at least one of the following steps a washing step, a rinsing step and water removal step. The controller is configured to control so as to rotate the rotatable drum at a predetermined rotational frequency and configured to control a spraying of the washing and/or rinsing water by the circulator onto the laundry in the rotatable drum based on the amount of foam detected by the foam detector.

[0137] Thereby, based on the amount of foam detected by the foam detector, the rotatable drum is rotated at the predetermined rotational frequency, to enhance the cleaning effect of laundry. For example, when there is much dirt on laundry, the foam detector judges that the amount of foam is small, and the rotatable drum is rotated at a predetermined rotational frequency at which the laundry sticks to the inner surface of the rotatable drum. As a result, the washing and/or rinsing water impregnated among the fibers of the laundry is discharged by centrifugal force together with dirt. Further, the washing and/or rinsing water is sprayed by the circulator onto the laundry in the rotatable drum, thereby loading (infiltrating) the washing and/or rinsing water into the fibers of the laundry. As a result, when there is much dirt on the laundry, replacement of the washing and/or rinsing water among the fibers of the laundry is promoted to accelerate a dirt removing effect so as to enhance a cleaning effect. Further, by detecting the amount of foam after the lapse of a predetermined time from the start of the washing step, it is possible to promote dissolution of the detergent by rotation of the rotatable drum, while accurately detecting the amount of foam.

[0138] Moreover in the rotatable drum type washing machine of the present invention, when the amount of foam detected by the foam detector is small, the controller rotates the rotatable drum at a predetermined rotational frequency at which the laundry sticks to the inner surface of the rotatable drum. Thereby, the washing and/or rinsing water in the vessel is rolled up and agitated by high-speed rotation of the rotatable drum. As a result, dissolution of the detergent and generation of foam are promoted, while the amount of foam can be more accurately detected.

[0139] Moreover in the rotatable drum type washing machine of the present invention, the controller rotates the rotatable drum at a rotational frequency at which the laundry sticks to the inner surface of the rotatable drum at a start of the washing step, and thereafter, the controller supplies the washing and/or rinsing water and the controller is configured to control to detect the amount of foam by the foam detector. Hence it is possible to rotate the rotatable drum from the start of the washing step, so as to supply water in a state where non-uniformity of the laundry is prevented. By driving the rotatable drum to be rotated at a high speed in the state where the laundry is not one-sided and is stable in rotatable drum 3, it is possible to sufficiently roll up and agitate the washing and/or rinsing water in the vessel, so as to promote dissolution of the detergent and generation of the foam. As a result, the amount of foam can be more accurately detected by the foam detector.

[0140] Moreover in the rotatable drum type washing machine of the present invention, the controller is configured to control to detect the amount of foam by the foam detector after the lapse of a predetermined time from the start of the washing step. Therefore, the rotatable drum is rotated until the predetermined time has elapsed, and hence it is possible to promote dissolution of the detergent into the washing and/or rinsing water, while promoting generation of foam. This can result in accurate detection of the amount of foam in accordance with dirt on the laundry, so as to control rotation of the rotatable drum.

[0141] Further in the rotatable drum type washing machine of the present invention, the washing step has: a low-speed agitating step of rotating the rotatable drum at such a speed at which the laundry is not attached to at least the inner surface of the rotatable drum, and a high-speed rotation step of rotating the rotatable drum at a speed at which the laundry does not stick to the inner surface of the rotatable drum, and the controller switches to the high-speed rotation step when the amount of foam detected by the foam detector comes into a predetermined condition during the low-speed agitating step.

[0142] According to this configuration, first, the rotatable drum is rotated at a low speed to bring the laundry into the state of being wet with washing and/or rinsing water sufficiently mixed with the detergent, and hence it is possible to efficiently attach the surfactant of the detergent to the dirt on the laundry. Subsequently, by rotating the rotatable drum at a high speed in accordance with the output of the foam detector, it is possible to peel from the laundry the dirt attached to the detergent and the washing and/or rinsing water mixed with the detergent in the vicinity of the fibers of the laundry. It is thereby possible to prevent unnecessary foaming of the detergent, to perform the cleaning operation as much as necessary. This can result in suppression of a wasteful operation and power consumption.

[0143] Further in the rotatable drum type washing machine of the present invention, when the amount of foam detected by the foam detector becomes not smaller than a predetermined value, the controller is configured not to perform the high-speed rotation step. Accordingly, when the dirt on the laundry is below the detergency of the amount of detergent inserted and the amount of foam generated is large, the cleaning operation is completed without rotating the rotatable drum at a high speed. This can reduce a load on the motor in the case of rotating the rotatable drum at a high speed in the state of excessive foam being generated, thereby allowing elimination of a wasteful operation and power consumption.

[0144] Further in the rotatable drum type washing machine of the present invention, when the amount of foam detected by the foam detector becomes not smaller than a predetermined value, the controller is configured to perform at least one of reduction in rotational frequency of the rotatable drum in the high-speed rotation step or reduction in duration of time for the high-speed rotation step.

[0145] According to this configuration, when the dirt on the laundry is below the detergency of the amount of detergent inserted and the amount of foam generated is excessive, there is a little dirt to be peeled from the laundry, and hence it is possible to perform at least either reduction in rotational frequency of the rotatable drum in the high-speed rotation step or reduction in time for the step. Therefore, it is possible to obtain sufficient cleaning performance and also suppress generation of excessive foaming. This can reduce a load on the motor in the case of rotating the rotatable drum at a high speed in the state of excessive foam being generated, thereby allowing elimination of a wasteful operation and power consumption.

[0146] Moreover, in the rotatable drum type washing machine of the present invention, the foam detector comprises the transparency sensor for detecting transparency of the washing and/or rinsing water for determining the amount of foam based on an output value of the transparency sensor. Hence it is possible to easily determine whether the amount of foam is large or small just by monitoring the transparency of the washing and/or rinsing water.

INDUSTRIAL APPLICABILITY

[0147] According to the present invention, it is possible to promote replacement of washing and/or rinsing water among fibers of laundry for accelerating removal of dirt, so as to enhance the cleaning effect, and hence the present invention is useful for such a technical field as a rotatable drum type washing machine.

REFERENCE MARKS IN THE DRAWINGS

[0148] 

1

enclosure

2

vessel, for example water tub

3

rotatable drum

3A

rotational shaft

4

baffle

5

small hole

6

opening

7

motor

8

belt

9

pulley

10

water supply valve (water supply unit)

11

water supply channel

12

detergent case

13

water tank unit

14

heater

15

temperature detector

16

circulation channel

17

circulation pump (circulator)

18

intake

19,30

outlet

20

switch valve

21

drainage channel

22

controller

23

door

24

operator

25

weight detector

26

water-level detector

27,28,32

foam detector

29

water supply inlet

31

filter

33

laundry

Claims

1. A rotatable drum type washing machine comprising:

a rotatable drum (3) for housing laundry (33);

a vessel (2) for housing the rotatable drum (3);

a motor (7) for driving the rotatable drum (3);

a water supply unit (10) for supplying washing and/or rinsing water into the vessel (2);

a foam detector (27, 32) for detecting an amount of foam in the vessel (2); and

a controller (22) for controlling at least one of the following steps a washing step, a rinsing step, and water removal step;

characterized by:

a circulator (17) being a circulation pump for circulating the washing and/or rinsing water in the vessel (2) into the rotatable drum (3);

wherein the controller is configured to control a spraying of the washing and/or rinsing water by the circulator (17) onto the laundry (33) in the rotatable drum (3) based on the amount of foam detected by the foam detector (27, 32); wherein
the washing step has the following steps:

a low-speed agitating step of rotating the rotatable drum (3) at a speed at which the laundry does not stick to at least an inner surface of the rotatable drum, and

a high-speed rotation step of rotating the rotatable drum (3) at a speed at which the laundry sticks to the inner surface of the rotatable drum, and wherein the controller (22) is configured to carry out at least one of the low-speed agitating step and the high-speed rotation step;

wherein the controller (22) is configured to carry out the high-speed rotation step of the washing step when the controller (22) determines that the amount of foam generated in the vessel (2) during the low-speed agitating step is smaller than a predetermined amount of foam by detecting the amount of foam generated in the vessel (2) by means of the foam detector (27, 32).

2. The rotatable drum type washing machine according to claim 1, wherein the controller (22) is configured to supply the washing and/or rinsing water and the controller (22) is configured to detect the amount of foam by means of the foam detector (27, 32) after rotating the rotatable drum (3) at a predetermined rotational frequency at which the laundry sticks to an inner surface of the rotatable drum (3), at a start of the washing step.

3. The rotatable drum type washing machine according to claim 1, wherein the controller (22) is configured to detect the amount of foam by the foam detector (27, 32) after a lapse of a predetermined time from a start of the washing step.

4. The rotatable drum type washing machine according to claim 1, wherein the controller (22) is configured not to perform the high-speed rotation step of the washing step when the controller (22) determines that the amount of foam generated in the vessel (2) becomes not smaller than a predetermined amount of foam by means of the foam detector (27, 32).

5. The rotatable drum type washing machine according to claim 1, wherein the controller (22) is configured to perform at least one of reduction in rotational frequency of the rotatable drum in the high-speed rotation step of the washing step and reduction in duration of time for the high-speed rotation step when the amount of foam generated in the vessel (2) becomes not smaller than a predetermined amount of foam by means of the foam detector (27, 32).

6. The rotatable drum type washing machine according to claim 1, wherein the foam detector (27) is configured by an electrode sensor made up of a pair of electrodes.

7. The rotatable drum type washing machine according to claim 1, wherein the foam detector (32) comprises a transparency sensor for detecting transparency of the washing and/or rinsing water for determining the amount of foam based on an output value of the transparency sensor.

Ansprüche

1. Waschmaschine mit rotierbarer Trommel, umfassend:

eine rotierbare Trommel (3) zur Unterbringung von Wäsche (33);

ein Behältnis (2) zur Unterbringung der rotierbaren Trommel (3);

einen Motor (7) zum Antreiben der rotierbaren Trommel (3);

eine Wasserzufuhreinheit (10) zum Zuführen von Wasch- und/oder Spülwasser in das Behältnis (2);

einen Schaumdetektor (27, 32) zum Erfassen einer Schaummenge in dem Behältnis (2); und

eine Steuerung (22) zum Steuern von mindestens einem der folgenden Schritte: ein Waschschritt, ein Spülschritt und ein Wasserablassschritt;

gekennzeichnet durch:

einen Zirkulator (17), der eine Umwälzpumpe zum Zirkulieren des Wasch- und/oder Spülwassers in dem Behältnis (2) in die rotierbare Trommel (3) ist;

wobei die Steuerung darauf konfiguriert ist, ein Versprühen des Wasch- und oder Spülwassers durch den Zirkulator (17) auf die Wäsche (33) in der rotierbaren Trommel (3) zu steuern, basierend auf der mit dem Schaumdetektor (27, 32) erfassten Schaummenge; wobei
der Waschschritt die folgenden Schritte hat:

einen niedrigtourigen Schüttelschritt, bei dem die rotierbare Trommel (3) mit einer Geschwindigkeit rotiert wird, bei der die Wäsche nicht an mindestens die innere Fläche der rotierbaren Trommel gedrückt wird, und

einen hochtourigen Rotationsschritt, bei dem die rotierbare Trommel (3) mit einer Geschwindigkeit rotiert wird, bei der die Wäsche an die innere Fläche der rotierbaren Trommel gedrückt wird, und wobei die Steuerung (22) darauf konfiguriert ist, mindestens einen des niedrigtourigen Schüttelschritts und des hochtourigen Rotationsschritts auszuführen;

wobei die Steuerung (22) darauf konfiguriert ist, den hochtourigen Rotationsschritt des Waschschritts auszuführen, wenn die Steuerung (22) bestimmt, dass die in dem Behältnis (2) während des niedrigtourigen Schüttelschritts erzeugte Schaummenge kleiner ist als eine vorbestimmte Schaummenge, durch Erfassen der in dem Behältnis (2) erzeugten Schaummenge mit dem Schaumdetektor (27, 32).

2. Waschmaschine mit rotierbarer Trommel nach Anspruch 1, wobei die Steuerung (22) darauf konfiguriert ist, das Wasch- und/oder Spülwasser zuzuführen, und wobei die Steuerung (22) darauf konfiguriert ist, die Schaummenge mit dem Schaumdetektor (27, 32) zu erfassen, nachdem die rotierbare Trommel (3) bei einer vorbestimmten Rotationsfrequenz rotiert wurde, bei der die Wäsche an eine innere Fläche der rotierbaren Trommel (3) gedrückt wird, und zwar zu Beginn des Waschschritts.

3. Waschmaschine mit rotierbarer Trommel nach Anspruch 1, wobei die Steuerung (22) darauf konfiguriert ist, die Schaummenge mit dem Schaumdetektor (27, 32) nach einer vorbestimmten Zeitspanne ab Beginn des Waschschritts zu erfassen.

4. Waschmaschine mit rotierbarer Trommel nach Anspruch 1, wobei die Steuerung (22) darauf konfiguriert ist, den hochtourigen Rotationsschritt des Waschschritts nicht auszuführen, wenn die Steuerung (22) bestimmt, dass die in dem Behältnis (2) erzeugte Schaummenge nicht kleiner wird als eine mit dem Schaumdetektor (27, 32) vorbestimmte Schaummenge.

5. Waschmaschine mit rotierbarer Trommel nach Anspruch 1, wobei die Steuerung (22) darauf konfiguriert ist, mindestens eines von Rotationsfrequenz der rotierbaren Trommel während dem hochtourigen Rotationsschritt des Waschschritts und Dauer des hochtourigen Rotationsschritts zu reduzieren, wenn die in dem Behältnis (2) erzeugte Schaummenge nicht kleiner wird als eine mit dem Schaumdetektor (27, 32) vorbestimmte Schaummenge.

6. Waschmaschine mit rotierbarer Trommel nach Anspruch 1, wobei der Schaumdetektor (27) von einem Elektrodensensor, bestehend aus einem Elektrodenpaar, konfiguriert ist.

7. Waschmaschine mit rotierbarer Trommel nach Anspruch 1, wobei der Schaumdetektor (32) einen Transparenzsensor zum Erfassen der Transparenz von Wasch- und/oder Spülwasser umfasst, um die Schaummenge basierend auf einem Ausgangswert des Transparenzsensors zu bestimmen.

Revendications

1. Machine à laver à tambour rotatif comprenant :

un tambour rotatif (3) destiné à recevoir le linge (33),

une cuve (2) destinée à contenir le tambour rotatif (3),

un moteur (7) destiné à entraîner le tambour rotatif (3),

une unité d'approvisionnement en eau (10) destinée à fournir de l'eau de lavage et/ou de rinçage à la cuve (2),

un détecteur de mousse (27, 32) destiné à détecter une quantité de mousse dans la cuve (2), et

un organe de commande (22) destiné à commander au moins une des étapes suivantes : une étape de lavage, une étape de rinçage et une étape d'évacuation de l'eau ;

caractérisée par :

un circulateur (17) consistant en une pompe de circulation destinée à faire circuler l'eau de lavage et/ou de rinçage de la cuve (2) au tambour rotatif (3) ;

l'organe de commande étant conçu pour commander une pulvérisation de l'eau de lavage et/ou de rinçage par le circulateur (17) sur le linge (33) présent dans le tambour rotatif (3) en fonction de la quantité de mousse détectée par le détecteur de mousse (27, 32) ;
l'étape de lavage comprenant les étapes suivantes :

une étape de malaxage à basse vitesse consistant à faire tourner le tambour rotatif (3) à une vitesse à laquelle le linge ne colle pas à au moins une surface interne du tambour rotatif, et

une étape de rotation à grande vitesse consistant à faire tourner le tambour rotatif (3) à une vitesse à laquelle le linge colle à la surface interne du tambour rotatif, l'organe de commande (22) étant conçu pour mettre en oeuvre l'étape de malaxage à basse vitesse et/ou l'étape de rotation à grande vitesse ;

l'organe de commande (22) étant conçu pour mettre en oeuvre l'étape de rotation à grande vitesse dans le cadre de l'étape de lavage lorsque l'organe de commande (22) détermine que la quantité de mousse générée dans la cuve (2) au cours de l'étape de malaxage à basse vitesse est inférieure à une quantité prédéterminée de mousse en détectant la quantité de mousse générée dans la cuve (2) au moyen du détecteur de mousse (27, 32).

2. Machine à laver à tambour rotatif selon la revendication 1, dans laquelle l'organe de commande (22) est conçu pour fournir l'eau de lavage et/ou de rinçage et l'organe de commande (22) est conçu pour détecter la quantité de mousse au moyen du détecteur de mousse (27, 32) après que le tambour rotatif (3) a tourné à une fréquence de rotation prédéterminée à laquelle le linge colle à la surface interne du tambour rotatif (3), au début de l'étape de lavage.

3. Machine à laver à tambour rotatif selon la revendication 1, dans laquelle l'organe de commande (22) est conçu pour détecter la quantité de mousse par l'intermédiaire du détecteur de mousse (27, 32) après l'écoulement d'une période prédéterminée à compter du début de l'étape de lavage.

4. Machine à laver à tambour rotatif selon la revendication 1, dans laquelle le détecteur (22) est conçu pour ne pas mettre en oeuvre l'étape de rotation à grande vitesse dans le cadre de l'étape de lavage lorsque l'organe de commande (22) détermine que la quantité de mousse générée dans la cuve (2) ne devient pas inférieure à une quantité prédéterminée de mousse au moyen du détecteur de mousse (27, 32).

5. Machine à laver à tambour rotatif selon la revendication 1, dans laquelle l'organe de commande (22) est conçu pour effectuer une réduction de la fréquence de rotation du tambour rotatif au cours de l'étape de rotation à grande vitesse dans le cadre de l'étape de lavage et/ou une réduction de la durée de l'étape de rotation à grande vitesse lorsque la quantité de mousse générée dans la cuve (2) ne devient pas inférieure à une quantité de mousse prédéterminée au moyen du détecteur de mousse (27, 32).

6. Machine à laver à tambour rotatif selon la revendication 1, dans laquelle le détecteur de mousse (27) est constitué par un capteur à électrodes composé d'une paire d'électrodes.

7. Machine à laver à tambour rotatif selon la revendication 1, dans laquelle le détecteur de mousse (32) comprend un détecteur de transparence destiné à détecter la transparence de l'eau de lavage et/ou de rinçage pour déterminer la quantité de mousse en fonction d'une valeur de sortie produite par le détecteur de transparence.

Drawing