WASHING MACHINE

Abstract

 A washing machine capable of improving a washing effect with little detergent solution in a structure for accommodating washings in a washing tub having an axis extending longitudinally is provided. The washing machine (1) includes: a washing tub (4) having an axis (J) extending longitudinally; a circulation path (11) configured to draw detergent solution mixed with a detergent in the washing tub (4) and return the detergent solution into the washing tub (4) from an upper side (Z1); a pump (12) configured to pump the detergent solution in the washing tub (4) into the circulation path (11) and allow the detergent solution to rise in the circulation path (11); and a controller (30) configured to execute a washing operation. The washing operation includes a circulation-soaking process during which a circulation process and a soaking process are conducted alternately and repeatedly. The detergent solution is circulated between the washing tub (4) and the circulation path (11) by driving the pump (12) and sprayed onto washings in the circulation process. The pump (12) is stopped from being driven and the washings are soaked with the detergent solution in the washing tub (4) in the soaking process.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a washing machine.

TECHNICAL FIELD

[0002] When washings are washed with detergent solution mixed with a detergent in a washing machine, the higher the concentration of the detergent solution is, the greater the washing effect caused by the detergent solution will be. In a drum-type washing machine disclosed in the following patent document 1, detergent solution of high concentration is distributed to the washings inside the drum from a hollow shaft of the washing machine. In a drum-type washing machine disclosed in the following patent document 2, washing water of high concentration is sprayed onto the washings in the drum, so that the washings can undergo a highly concentrated washing.

[0003] Prior to a main washing process of washing the washings normally, sometimes washings need to be soaked. The washings are soaked in the detergent solution during a soaking to make dirt dissolve out, causing it easier to remove the dirt in the subsequent main washing process. Generally, the soaking is performed by utilizing the detergent solution the amount of which is substantially the same as that during the whole main washing process. In the case that the washing effect of soaking is improved by increasing the concentration of the detergent solution, a cost of the detergent increases if the amount of the detergent is increased.

[0004] Conversely, if the concentration of the detergent solution is increased by decreasing the amount of water without increasing the amount of the detergent, it is difficult to spray the detergent solution to the washings uniformly because only little detergent solution is produced. In particular, unlike the drum-type washing machine disclosed in Patent Document 1 and the drum-type washing machine disclosed in Patent Document 2, for a vertical type washing machine including a washing tub the axis of which extends longitudinally, the detergent solution tends to be stored at the bottom of the washing tub, thus there is a possibility that only lower part of the washings in the washing tub is soaked in the detergent solution. In this way, it is difficult to improve the cleaning effect of the washings by the detergent solution.

Related Technical Literatures

Patent Literatures

[0005] 

Patent Literature 1: Japanese Laid-Open Patent Publication No. 2005-65873

Patent Literature 2: Japanese Patent Publication No. 2008-534049

SUMMARY

[0006] The problem to be solved by the present disclosure

[0007] The present disclosure is made in view of the above, and aims to provide a washing machine capable of improving the cleaning effect with little detergent solution in a structure accommodated with washings in a washing tub having an axis that extends longitudinally.

The solution to the technical problem

[0008] The present disclosure relates to a washing machine, including a washing tub having an axis extending longitudinally, where the washing tub is configured to accommodate washings and is capable of storing water; a circulation path configured to draw detergent solution mixed with a detergent in the washing tub and return the detergent solution into the washing tub from an upper side; a pump configured to pump the detergent solution in the washing tub into the circulation path and allow the detergent solution to rise in the circulation path; and an execution unit configured to execute a washing operation. The washing operation includes a circulation-soaking process during which a circulation process and a soaking process are conducted alternately and repeatedly. The detergent solution is circulated between the washing tub and the circulation path by driving the pump and sprayed onto washings in the circulation process. The pump is stopped from being driven and the washings are soaked with the detergent solution in the washing tub in the soaking process.

[0009] Furthermore, the washing machine according to the present disclosure includes a motor for rotating the washing tub. The execution unit is configured to drive the motor to rotate the washing tub at a low speed below a predetermined rotation speed in at least one circulation process.

[0010] Furthermore, the washing machine according to the present disclosure includes a motor for rotating the washing tub. The execution unit is configured to drive the motor to rotate the washing tub repeatedly an intermittently in at least one circulation process.

[0011] Furthermore, the washing machine according to the present disclosure includes a motor for rotating the washing tub. During the circulation-soaking process, the execution unit is configured to cause the washing tub to stop in the circulation process, and drive the motor to rotate the washing tub merely for a predetermined angle prior to starting a next circulation process.

[0012] Furthermore, the washing machine according to the present disclosure includes a water supply path configured to supply water to the washing tub, and a water supply valve configured to open and close the water supply path. The washing operation includes a washing process consisting of the circulation-soaking process and a normal washing process. In the normal washing process, water is accumulated in the washing tub to perform a normal washing of the washings after the circulation-soaking process. During the circulation-soaking process, the execution unit is configured to open the water supply valve, so as to supply a part of a total water supply amount in the whole washing process to the washing tub and generate the detergent solution.

[0013] Furthermore, the washing machine according to the present disclosure includes a detergent container connected to the water supply path and containing the detergent. The water supply path is provided with a discharge opening, and water flowing through the water supply path after passing through the detergent container is discharged from the discharge opening toward a position away from the washings in the washing tub.

[0014] Furthermore, the execution unit is configured to change a time for performing the circulation process and a time for performing the soaking process according to load amount of the washings inside the washing tub.

The effect of the present disclosure

[0015] According to the present disclosure, a washing machine accommodates washings and stores water in a washing tub having an axis extending longitudinally. Inside the washing tub, the detergent solution mixed with a detergent is pumped into the circulation path by a pump, rises in the circulation path, and then returns into the washing tub from the upper side.

[0016] The execution unit executes a washing operation including a circulation-soaking process, in which a circulation process and a soaking process are conducted alternately and repeatedly. The detergent solution is circulated between the washing tub and the circulation path by driving the pump and sprayed onto washings in the circulation process. The pump is stopped from being driven and the washings are soaked with the detergent solution in the washing tub in the soaking process.

[0017] Even if there is little detergent solution, the detergent solution is repeatedly sprayed onto the washings in the washing tub by a plurality of circulation processes, and thus is uniformly sprayed to the washings. Through the soaking process after each circulation process, the same effect identical to steeping can be obtained. As a result, dirt is effectively dissolved out of the whole washings. Therefore, the cleaning effect can be improved with little detergent solution.

[0018] Further, according to the present disclosure, the execution unit is configured to drive the motor to rotate the washing tub at a low speed below a predetermined rotation speed in at least one circulation process. Thus, the detergent solution returned to the washing tub from the circulation path can be uniformly sprayed onto the washings in the washing tub over the entire region in the rotation direction of the washing tub. Therefore, it is possible to further improve the cleaning effect brought by the detergent solution.

[0019] Further, according to the present disclosure, the execution unit is configured to drive the motor to rotate the washing tub repeatedly and intermittently in at least one circulation process. Thus, the detergent solution returned to the washing tub from the circulation path can be uniformly sprayed onto the washings in the washing tub over the entire region in the rotation direction of the washing tub. Therefore, it is possible to further improve the cleaning effect brought by the detergent solution.

[0020] Further, according to the present disclosure, in the circulation-soaking process, the execution unit is configured to stop the washing tub during the circulation process, and drive the motor to rotate the washing tub for a predetermined angle before starting the next circulation process. As a result, when the washing tub is stopped in the circulation process, it is possible to spray the washing water intensively in one part of the washing tub containing the washings in the rotation direction. Then, the washing tub rotates a little before starting the next circulation process, so that in the next circulation process, the washing water is sprayed intensively to the other parts except the part where the washing water was sprayed in the previous circulation process of the washings. By repeating the circulation process several times while gradually changing the position where the detergent solution is sprayed to the washings in such a manner, a sufficient amount of detergent solution is eventually sprayed to the washings in the washing tub from the region of the washing tub in the rotation direction. Therefore, it is possible to further improve the cleaning effect brought by the detergent solution.

[0021] Further, according to the present disclosure, in the case that the washing process is constituted by the circulation-soaking process and a normal washing process, the execution unit is configured to open the water supply valve in the circulation-soaking process before the normal washing process to supply water to the water supply path, so that a part of a total water supply amount determined throughout the washing process is supplied to the washing tub to generate the detergent solution. As a result, a detergent solution of high concentration can be produced.

[0022] Further, according to the present disclosure, the discharge opening of the water supply path discharges the water containing the detergent passing through the detergent container toward the position away from the washings in the washing tub. As a result, it is possible to prevent the following situation: the detergent having an excessively high concentration only adheres to a part of the surface of the washings Q before being dissolved into the water, so that it is difficult to clean the entire washings uniformly.

[0023] Further, according to the present disclosure, since the execution unit is configured to change the time for performing the circulation process and the time for performing the soaking process according to the load amount of the washings in the washing tub, the most suitable circulation-soaking process is performed according to the load. Therefore, the cleaning effect brought by the detergent solution in the circulation-soaking process can be further improved.

BRIEF DESCRIPTION OF DRAWINGS

[0024] 

FIG. 1 is a schematic view illustrating a washing machine according to an embodiment of the present disclosure.

FIG. 2 is a block diagram illustrating an electrical structure of the washing machine.

FIG. 3 is a flowchart illustrating a control operation in a circulation-soaking process.

FIG. 4 is a schematic view illustrating a washing machine according to a first modification.

FIG. 5 is a schematic diagram illustrating a washing machine according to a second modification.

FIG. 6 is a schematic view illustrating a washing machine according to a third modification.

List of numerals

[0025] 1: Washing machine; 4, Washing tub; 5, Motor; 6, Water supply path; 6B: Discharge opening; 7: Water supply valve; 8, Detergent container; 11, Circulation path; 12, Pump; 30, Controller; J: Axis; Q, Washings; Z1: Upper side

DETAILED DESCRIPTION

[0026] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram illustrating a washing machine 1 according to an embodiment of the present disclosure. An up-down direction in FIG. 1 is called as an up-down direction Z of the washing machine 1, and a left-right direction in FIG. 1 is called as a lateral direction Y of the washing machine 1. The up-down direction Z coincides with the vertical direction, and the lateral direction Y coincides with the horizontal direction. In the up-down direction Z, the upper side is referred to as an upper side Z1 and the lower side is referred to as a lower side Z2. Although the washing machine 1 may be a washing/drying machine having a drying function, the washing machine 1 will be described by taking a washing machine, in which the drying function is omitted and only the washing operation is executed, as an example. The washing machine 1 includes a housing 2, an outer tub 3 disposed in the housing 2, a washing tub 4, a motor 5, a water supply path 6, a water supply valve 7, a detergent container 8, a drainage path 9, a drain valve 10, a circulation path 11 and a pump 12.

[0027] The housing 2 is, for example, made of metal, and is formed in a box shape. An entrance 2B for communicating the inside and outside of the housing 2 is formed at an upper surface 2A of the housing 2. The upper surface 2A is provided with a door 14 for opening/closing the entrance 2B and a display operation portion 15 including a switch, a liquid crystal panel and the like. A user operates the switch or the like of the display operation portion 15 to turn on/off the power of the washing machine 1, set a washing operation mode freely, or issue an instruction for activating or stopping the washing operation to the washing machine 1. Information related to the washing operation is visually displayed on the liquid crystal panel or the like of the display operation portion 15.

[0028] The outer tub 3 is, for example, made of resin, formed into a bottomed cylindrical shape and elastically supported by the housing 2 via an elastic supporting member (not shown) such as a so-called hanger rod. The outer tub 3 can store water therein. An imaginary straight line passing through a center of the circle of the outer tub 3 is axis J of the outer tub 3. The axis J extends in the vertical direction or in a direction slightly inclined with respect to the vertical direction, that is, in a longitudinal direction. The bottomed cylindrical outer tub 3 includes a substantially cylindrical circumferential wall 3A arranged around the axis J, a disk-shaped bottom wall 3B for sealing the circumferential wall 3A from the lower side Z2, and a ring-shaped annular wall 3C formed by crimping an upper edge of the circumferential wall 3A to protrude toward the axis J. The outer tub 3 is formed with a circular entrance 3D which is encircled by the annular wall 3C and opposed to the entrance 2B of the housing 2 from the lower side Z2, and a through hole 3E penetrating the center of the bottom wall 3B in the vertical direction Z.

[0029] The washing tub 4 is a metallic drum formed into a bottomed cylindrical shape slightly smaller than the outer tub 3, and can accommodate the washings Q therein. The washing tub 4 is coaxially arranged in the outer tub 3. Therefore, the axis of the washing tub 4 is the axis J aforementioned. The bottomed cylindrical washing tub 4 includes a substantially cylindrical circumferential wall 4A arranged around the axis J, a disk-shaped bottom wall 4B for sealing the circumferential wall 4A from the lower side Z2, a ring-shaped annular wall 4C formed by crimping an upper edge of the circumferential wall 4A to protrude toward the axis J. The washing tub 4 is formed with a circular entrance 4D which is encircled by the annular wall 4C and opposed to the entrance 3D of the outer tub 3 from the lower side Z2, and a plurality of through holes 4E formed on the circumferential wall 4A or the bottom wall 4B.

[0030] When the door 14 described above is opened, the entrance 2B, the entrance 3D and the entrance 4D are aligned in the vertical direction Z and are exposed to the upper side Z1 from the upper surface 2A of the housing 2, so that the washings Q are threw into/taken out of the washing tub 4 by means of the entrances. The water in the outer tub 3 flows between the outer tub 3 and the washing tub 4 via the through holes 4E, and is stored in the washing tub 4. Therefore, the water level in the outer tub 3 and the water level in the washing tub 4 coincide with each other. At the circular center of the bottom wall 4B, a rotation shaft 17 protruding to the lower side Z2 along the axis J is provided. The rotation shaft 17 is inserted into the through hole 3E of the bottom wall 3B of the outer tub 3 from the upper side Z1.

[0031] The motor 5 is constituted by, for example, a frequency conversion motor. The motor 5 is disposed on the lower side Z2 of the outer tub 3 in the housing 2, and is fixed to the bottom wall 3B of the outer tub 3 via a fixed part (not shown) or the like. The motor 5 has an output shaft 18 that rotates about the axis J. The output shaft 18 is connected to the rotation shaft 17 of the washing tub 4. When the motor 5 is driven, the driving force generated by the motor 5 is transmitted from the output shaft 18 to the rotation shaft 17 to drive the washing tub 4 to rotate around the axis J. It should be noted that a transmission mechanism (not shown) consisted of a clutch or the like may also be sandwiched between the rotation shaft 17 and the output shaft 18. Further, the washing tub 4 is provided with a pulsator (not shown) that rotates to stir the contained washings Q, and the driving force of the motor 5 may be selectively transmitted from the transmission mechanism to one or both of the washing tub 4 and the pulsator. In addition, in this embodiment, for convenience of explanation, the rotation number of the motor 5 is the same as the rotation number of the washing tub 4 and the pulsator.

[0032] The water supply path 6 is a flow path which has one end 6A connected to a faucet (not shown) and the other end 6C formed with a discharge opening 6B. The other end 6C of the water supply path 6 penetrates the annular wall 3C of the outer tub 3 from the upper side Z1, and the discharge opening 6B is configured to face a gap 19 in the lateral direction Y between the circumferential wall 3A of the outer tub 3 and the circumferential wall 4A of the washing tub 4 from the upper side Z1.

[0033] The water supply valve 7 is provided in the water supply path 6. When the water supply valve 7 is opened, the water supply path 6 is opened. In this way, through the water supply path 6, the water from the faucet flows down to the gap 19 from the discharge opening 6B, and is accumulated in the outer tub 3, as shown by a thick solid arrow. At this time, the discharge opening 6B discharges the water flowing through the water supply path 6 toward the gap 19 between the outer tub 3 and the washing tub 4, that is, the discharge opening 6B discharges the water toward a position away from the washings Q in the washing tub 4. The water accumulated in the outer tub 3 passes through the through holes 4E of the washing tub 4 to be accumulated in the washing tub 4. In this way, when the water supply valve 7 is opened, the water is supplied to the washing tub 4 from the water supply path 6. On the other hand, the water supply path 6 is closed when the water supply valve 7 is closed, and thus no water is supplied.

[0034] The detergent container 8 is formed as a box for containing the detergent, and is connected to the middle of the water supply path 6. The internal space of the detergent container 8 constitutes a middle section of the water supply path 6. When the water supply valve 7 is opened to supply water, the water from the faucet passes through the detergent container 8 to carry the detergent, flows through the water supply path 6 and is supplied from the discharge opening 6B to the outer tub 3 and the washing tub 4. As a result, the detergent solution mixed with the detergent is stored in the outer tub 3 and the washing tub 4.

[0035] The drainage path 9 is a flow path having an end 9A and another end 9B. The end 9A is connected to the bottom wall 3B of the outer tub 3 from the lower side Z2 at a position other than the through hole 3E. The end 9B is drawn out of the housing 2 at a position lower than the end 9A.

[0036] The drain valve 10 is provided in the drainage path 9. When the drain valve 10 is opened, the drainage path 9 is opened. Accordingly, the detergent solution accumulated in the outer tub 3 and the washing tub 4 is discharged to the outside of the machine through the drainage path 9. In this way, after the water is drained off, the drainage path 9 is closed when the drain valve 10 is closed, thus the drainage is stopped.

[0037] The circulation path 11 is a flow path having an end 11A and another end 11C. The end 11A is connected to a section of the drainage path 9, which is between the end 9A and the drain valve 10. The end 11C is formed with a discharge opening 11B. The circulation path 11 is bent after extending in the lateral direction Y from the end 11A, extends to the upper side Z1 through a gap between the housing 2 and the outer tub 3, and is bent toward the axis J side to reach the end 11C. The end 11C is bent toward the lower side Z2 just above the entrance 3D of the outer tub 3. The discharge opening 11B opens at the lower end of the end 11C, and faces the entrance 4D of the washing tub 4 from the upper side Z1.

[0038] The pump 12 is a centrifugal pump equipped with a rotating impeller (not shown) or the like, and is provided in the circulation path 11. When being driven, the pump 12 pumps the detergent solution in the outer tub 3 and the washing tub 4 into the end 11A of the circulation path 11 via the drainage path 9, so as to raise the detergent solution in the circulation path 11. As a result, the detergent solution is pumped into the circulation path 11 from the outer tub 3 and the washing tub 4, and is discharged from the water discharge opening 11B at the end 11C. The detergent solution discharged from the discharge opening 11B flows down to the entrance 4D of the washing tub 4 as indicated by a thick broken line arrow, and is returned to the washing tub 4 from the upper side Z1. When the pump 12 is continuously driven, the detergent solution circulates between the washing tub 4 and the circulation path 11.

[0039] The washing machine 1 includes a controller 30 as an execution unit. The controller 30 is, for example, a microcomputer including a central processing unit (CPU) and a memory such as a read only memory (ROM) and a random access memory (RAM), and is disposed in the housing 2.

[0040] Referring to FIG. 2, i.e. a block diagram illustrating an electrical structure of the washing machine 1, the washing machine 1 further includes a water level sensor 31, a rotation sensor 32, and a timer 33 for measuring time. Each of the water level sensor 31, the rotation sensor 32 and the timer 33 and the motor 5, the pump 12, the display operation portion 15, the water supply valve 7 and the drain valve 10 described above is electrically connected to the controller 30.

[0041] The water level sensor 31 is a sensor for detecting the water level of the outer tub 3 and the washing tub 4, and a detection result of the water level sensor 31 is input to the controller 30 in real time.

[0042] The rotation sensor 32 is a device for reading the number of revolutions of the motor 5, strictly speaking, the number of revolutions of the output shaft 18 of the motor 5. For example, the rotation sensor 32 is formed by a Hall IC (not shown) that outputs a pulse each time the output shaft 18 rotates by a predetermined rotation angle. The number of revolutions read by the rotation sensor 32 is input to the controller 30 in real time. The controller 30 controls a voltage applied to the motor 5 based on the input number of revolutions. More specifically, the controller 30 controls the duty ratio of the voltage applied to the motor 5 to drive the motor 5 to rotate at the desired number of revolutions. The controller 30 also controls the driving of the pump 12.

[0043] As described above, in response to selecting operation conditions of the washing operation by the user through the display operation portion 15, the controller 30 accepts the selection. The controller 30 performs control to display information necessary to the user in the display operation portion 15 in a visible manner. The controller 30 controls opening/closing of the water supply valve 7 and the drain valve 10. Therefore, the controller 30 can supply water to the washing tub 4 by opening the water supply valve 7 with the drain valve 10 being closed, and can drain the washing tub 4 by opening the drain valve 10.

[0044] Next, the washing operation executed by the controller 30 in the washing machine 1 will be described. The washing operation includes a washing process consisting of an original circulation-soaking process and a normal washing process after the circulation-soaking process, a rinsing process after the washing process, and a dewatering process. The circulation-soaking process may be regarded as an independent process in the washing operation or may be regarded as part of the washing process as in the present embodiment. The dewatering process includes a final dewatering process executed at the end of the washing operation and an intermediate dewatering process executed after the washing process and the rinsing process.

[0045] The controller 30 detects the amount of washings Q in the washing tub 4 as a load amount before starting the washing operation. The unit of the load amount is, for example, kg. As an example of detecting the load amount, the controller 30 may acquire the load amount from the weight of the washings Q detected by a weight sensor (not shown) provided in the washing machine 1. Further, the load amount may be detected by variations in the number of revolutions of the motor 5 when the washing tub 4 is steadily rotated at a low speed. In the case that the pulsator described above is provided, the controller 30 stops the driving of the motor 5 immediately after rotating the pulsator carried with the washings Q for a predetermined time, thereby rotating the motor 5 inertly, and the inertial rotation amount of the motor 5 at that time is measured. The larger the load amount is, the smaller the inertial rotation amount of the motor 5 connected to the pulsator carried with the heavy washings Q will be. The smaller the load amount is, the larger the inertia rotation amount of the motor 5 connected to the pulsator carried with the light washings Q will be. The controller 30 detects the load amount according to the magnitude of the inertia revolutions.

[0046] The circulation-soaking process will be described with reference to the flowchart of FIG. 3. During the circulation-soaking process, the drain valve 10 is always in a closed state. As the circulation-soaking process starts, the controller 30 controls the water supply valve 7 to open for a predetermined time to supply water to the washing tub 4 (step S1). As a result, the detergent solution is accumulated in the washing tub 4 to a predetermined water level.

[0047] Next, the controller 30 performs the circulation process for the first time (step S2). In the circulation process, the controller 30 controls the pump 12 to circulate the detergent solution between the washing tub 4 and the circulation path 11, and the detergent solution is sprayed to the washings Q in the washing tub 4 from the discharge opening 11B of the circulation path 11 during the circulation process. The time for performing the circulation process, that is, the time for driving the pump 12 is, for example, about 15 seconds. Moreover, the detergent solution which has passed through the pump 12 in the circulation path 11 is finely crushed by the impeller of the pump 12 and dissolved in water, so that the detergent solution of high concentration is generated.

[0048] Next, the controller 30 performs the soaking process for the first time (step S3). In the soaking process, the controller 30 performs control to stop the driving of the pump 12 to soak the washings Q in the detergent solution in the washing tub 4. Specifically, the detergent solution sprayed from the upper side Z1 to the washings Q in the circulation process soaks into the washings Q due to its own weight. In addition, in the soaking process, since the drain valve 10 is continuously closed, the detergent solution is accumulated in the washing tub 4 so that the washings Q, particularly the lower part of the washings Q, is immersed in the detergent solution. The time for performing the soaking process, that is, the time during which the pump 12 is stopped is, for example, about 45 seconds.

[0049] Next, the controller 30 performs the circulation process for the second time (step S4), and then performs the soaking process for the second time (step S5). In addition, since the pump 12 is stopped in the soaking process just before the circulation process, at the start of the circulation process, the detergent solution is in a state of being accumulated in the outer tub 3 and the washing tub 4 and accumulated at the end 11A of the drainage path 9 and the circulation path. Therefore, during the circulation process immediately after the soaking process, the pump 12 can promptly start the circulation of detergent solution without idling. Further, in the first circulation process, since the washings Q before washing are dry and can absorb a large amount of detergent solution, the time for the first circulation process is set to be longer. However, the washings Q are in a state of having absorbed a certain amount of detergent solution since the start of the second circulation process, the time for the circulation process is set to be shorter than that of the first circulation process. Based on the same reason, the time for the first soaking process is set to be longer in the first soaking process, while the time for subsequent soaking processes since the second soaking process is set to be shorter than that of the first soaking process.

[0050] The controller 30 alternately repeats the circulation process (step S4) and the soaking process (step S5) for a plurality of times until a predetermined time has elapsed from supplying water in step S1 (No in step S6). The predetermined time herein is, for example, 30 minutes. In this case, the circulation process and the soaking process are repeated 30 times in total. Even if there is little detergent solution, the detergent solution is uniformly applied to the washings Q in the washing tub 4 repeatedly through a plurality of circulation processes, and the washings Q are brought to a state equivalent to being soaked in the detergent solution through the soaking processes after the circulation processes. As a result, the dirt is effectively dissolved out the washings Q. Therefore, the cleaning effect can be improved with little detergent solution.

[0051] When the predetermined time has elapsed (Yes in step S6), the circulation-soaking process is completed, and the controller 30 performs the next process, i.e., the normal washing process. When the normal washing process is started, the controller 30 controls the water supply valve 7 to open with the drain valve 10 being continuously closed, so as to supply water to the washing tub 4 additionally. As a result, the detergent solution is accumulated in the washing tub 4 to a water level higher than the water level of the detergent solution accumulated due to the supplied water in step S1. In the normal washing process, the controller 30 drives the motor 5 under a state that the detergent solution is stored in the washing tub 4, so as to rotate the washing tub 4 or the pulsator described above. As a result, a water flow of the detergent solution is generated in the washing tub 4 to stir the washings Q. The dirt is removed from the washings Q by the mechanical force such as friction and vibration given to the washings Q by the water flow, or the dirt is chemically decomposed by the detergent solution, whereby the washings Q are washed formally. In particular, due to the circulation-soaking process before the normal washing process, the washings Q are in a state that the dirt is dissolved out to be easily removed, thus a high cleaning effect can be exhibited in the normal washing process.

[0052] The controller 30 may further execute a first process, in which the motor 5 is driven to rotate the washing tub 4 at a low speed below a predetermined rotation speed, in at least one circulation process. The number of revolutions of the motor 5 when the washing tub 4 is rotated at a low speed is, for example, 50 rpm. In addition, the number of revolutions of the motor 5 when the washing tub 4 is rotated at a high speed in the dewatering process is, for example, 600 rpm to 800 rpm. By rotating the washing tub 4 at a low speed in the circulation process, it is possible to suppress the bias of the washings Q in the washing tub 4, and prevent the detergent solution in the washing tub 4 from being scattered to the outside from the entrance 4D. Further, the controller 30 may further execute a second process, in which the motor 5 is driven to perform an intermittent rotation of the washing tub 4 repeatedly, in at least one circulation process. The intermittent rotation of the washing tub 4 refers to stopping or rotating the washing tub 4 repeatedly by turning on or turning off the motor 5 repeatedly.

[0053] Through the first process and the second process, the detergent solution returned to the washing tub 4 from the circulation path 11 is sprayed to the washings Q in the washing tub 4 over the entire region in the rotation direction of the washing tub 4. Therefore, it is possible to further improve the cleaning effect by detergent solution.

[0054] The controller 30 can also perform a third process, in which the washing tub 4 is stopped during the circulation process and the motor 5 is driven to rotate the washing tub 4 for only a predetermined angle before starting the next circulation process, in the circulation-soaking process. In this way, when the washing tub 4 is stopped during the circulation process, it is possible to intensively spray the washing water on a part of the washings Q in the rotational direction the washing tub 4 containing. Then, the washing tub 4 slightly rotates before starting the next circulation process, so that in the next circulation process, the washing water is intensively sprayed on a part of the washings Q other than the part sprayed by the washing water in the previous circulation process. By repeating the circulation process a plurality of times while slightly changing the position of the washings Q immersed in the detergent solution, a sufficient amount of detergent solution is uniformly sprayed to the washings Q in the washing tub 4 over the entire region in the rotation direction of the washing tub 4 finally. Therefore, the cleaning effect caused by the detergent solution is further improved. It should be noted that, in the case of the third process, the washing tub 4 may stop or rotate in a soaking process immediately after the circulation process in which the washing tub 4 stopped. In the case that the washing tub 4 rotates in the soaking process, the controller 30 temporarily stores the stop position of the washing tub 4 in the previous circulation process.

[0055] In the circulation-soaking process, only one of the first process, the second process and the third process may be performed, or a combination of the first process, the second process and the third process may be carried out. For example, in the first to fifth circulation process in the early stage of the circulation-soaking process, only the first process is performed, and in the sixth circulation process and subsequent circulation processes, only the third process is performed. In this case, it is possible to uniformly spray the detergent solution throughout the whole washings Q at an early stage in the circulation-soaking process through the first to fifth circulation process, and in subsequent circulation process since the sixth circulation process, a large amount of detergent solution is locally sprayed to the washings Q, so that it is possible to improve the cleaning effect of the part of the washings Q immersed in the detergent solution.

[0056] Further, a combination of the first to third processes can be arbitrarily set according to the load amount of the washings Q and the washing operation mode. For example, in the case that the load amount is small due to a small amount of washings Q or under a mode in which cotton easy to absorb water is washed, the detergent solution is easily immersed into the lower part of the washings Q even if little detergent solution is uniformly sprayed to the washings Q. Therefore, the frequencies of the first and second processes are increased, and the frequency of the third process is reduced. On the other hand, in the case that the load amount is large due to the large number of washings Q or under a mode in which thick blankets are washed, if no large amount of detergent solution is intensively sprayed on a part of the washings Q, the detergent solution can hardly immerse into the lower part of the washings Q. Therefore, the frequency of the third process is increased, and the frequencies of the first and second processes are reduced.

[0057] The controller 30 may open the water supply valve 7 in step S1 of the circulation-soaking process, so as to supply a part of water supplied during the entire washing process to the washing tub 4 to generate the detergent solution. That is, the detergent solution is generated in the circulation-soaking process by using a part of the water supply amount predetermined in the entire washing process. As a result, it is possible to generate the detergent solution of high concentration without increasing the amount of water supplied during the entire washing operation. In addition, the water supply amount in the whole washing process is, for example, 60 L. In this case, the water supply amount in the circulation-soaking process is set to be about ⅓ to ½ of 60 L, for example, 20 L.

[0058] In this manner, in the circulation process, by generating high-concentration detergent solution with little detergent and water and repeating the circulation-soaking process in which the detergent solution is uniformly immersed into the washings Q via the pump 12, it is possible to obtain the same cleaning effect as that obtained in the case of washing by using a large amount of detergent solution of high concentration. In addition, the high concentration herein is, for example, a range of 2 to 3 times the concentration.

[0059] In addition, as described above, when water is supplied in step S1, water containing the detergent, which has passed through the detergent container 8, is discharged from the discharge opening 6B of the water supply path 6 to the position away from the washings Q in the washing tub 4. That is, during the supplying water in the circulation-soaking process, the water containing the detergent from the detergent container 8 is supplied without being sprayed on the washings Q directly. As a result, it is possible to prevent the following situation: the detergent having an excessively high concentration only adheres to a part of the surface of the washings Q before being dissolved into the water, so that it is difficult to clean the entire washings uniformly.

[0060] The controller 30 may also change the time of the circulation process and the time of the socking process according to the load amount of the washings Q in the washing tub 4 respectively. Specifically, when the load is large due to large number of washings Q, it is necessary to spray a large amount of detergent solution on the washings Q to immerse the washings, thus the time of the circulation process and the time of the soaking process are generally set by the controller 30 to be long. On the other hand, when the load is little due to a small amount of washings Q, a sufficient washing effect can be obtained by spraying little detergent solution to immerse the washings Q, thus the time of the circulation process and the time of the soaking process are generally set by the controller 30 to be short. As a result, it is possible to execute a most suitable circulation-soaking process on the basis of the load amount. Therefore, the cleaning effect brought by the detergent solution in the circulation-soaking process can be further improved.

[0061] The present disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims.

[0062] For example, in the embodiment described above, the end 11A of the circulation path 11 is connected to the drainage path 9 (see FIG. 1), but it may be connected to the lower end of the outer tub 3.

[0063] FIG. 4 is a schematic view illustrating a washing machine 1 according to a first modification. FIG. 5 is a schematic diagram illustrating a washing machine 1 according to a second modification. FIG. 6 is a schematic diagram illustrating a washing machine 1 according to a third modification. In FIGS. 4 to 6, the same parts as those described with reference to FIG. 1 are denoted by the same reference numerals, and a description thereof will be omitted. As shown in the first to third modifications of FIGS. 4 to 6, the washing machine 1 may further include a tank 21.

[0064] Referring to FIG. 4, the tank 21 has a capacity capable of storing the detergent solution generated in the circulation washing process, and is disposed in the housing 2 in a space that is closer to the lower side Z2 than the outer tub 3 is. The tank 21 is interposed in the drainage path 9, and is located between a connecting portion between the end 11A of the circulation path 11 and the drainage path 9 and the end 9A of the drainage path 9. The internal space of the tank 21 constitutes an intermediate portion of the drainage path 9. A drain valve 22 is provided between the end 9A and the tank 21 in the drainage path 9. Hereinafter, for convenience of description, the drain valve 10 is referred to as a first drain valve 10, and the drain valve 22 is referred to as a second drain valve 22. The opening and closing of the second drain valve 22 is controlled by the controller 30.

[0065] When both the first drain valve 10 and the second drain valve 22 are opened, the water flowing to the drainage path 9 from the outer tub 3 is discharged outside the machine once it passes through the tank 21 and reaches the other end 9B. On the other hand, when the first drain valve 10 is closed with the second drain valve 22 being opened, the water flowing to the drainage path 9 from the outer tub 3 is stored in the tank 21 rather than being discharged outside the machine. The tank 21 is connected to an end 23A of an air vent pipe 23 from the upper side Z1. The air vent pipe 23 extends from the end 23A to the upper side Z1, and another end 23B of the air vent pipe 23 is connected to the upper portion of the circumferential wall 3A of the outer tub 3. As a result, the air in the tank 21 escapes into the outer tub 3 through the air vent pipe 23, so that the water flowing to the drainage path 9 from the outer tub 3 can flow smoothly into the tank 21. Moreover, even if bubbles in the tank 21 enter the air vent pipe 23, the bubbles are guided into the outer tub 3, thus it is possible to prevent the bubbles from blocking the air vent pipe 23.

[0066] In the first to third modifications, the controller 30 executes the circulation-soaking process illustrated in FIG. 3. In the circulation-soaking process, the first drain valve 10 is always in a closed state, and the second drain valve 22 may be opened and closed as necessary. In addition, when the second drain valve 22 is always opened, since the tank 21 functions only as a part of the drainage path 9, a circulation-soaking process, which is the same as that performed in the case that the tank 21 is not provided, is executed.

[0067] On the other hand, in the circulation-soaking process in which the second drain valve 22 is opened or closed as needed, the detergent solution is accumulated in the tank 21 because the controller 30 performs control to supply water with the second drain valve 22 being opened in Step S1. Then, the controller 30 alternately repeats the circulation process and the soaking process until the predetermined time elapsed in step S6.

[0068] In the circulation process in step S2 or step S4, after the detergent solution stored in the tank 21 is pumped into the circulation path 11 by the pump 12, the detergent solution is sprayed to the washings Q in the washing tub 4 from the upper side Z1 by means of the discharge opening 11B of the circulation path 11 (see the thick dashed arrow in FIG. 4). The detergent solution sprayed to the washings Q is accumulated in the tank 21 through the drainage path 9, pumped into the circulation path 11 again by the pump 12, and is sprayed to the washings Q. As a result, in the circulation process, the detergent solution circulates between the washing tub 4 and the circulation path 11 via the tank 21. It should be noted that, in the first circulation process in step S2, in order to immerse a large amount of detergent solution into the washings Q in a dry state before washing, the second drain valve 22 may be closed so that the detergent solution is stored in the washing tub 4.

[0069] On the other hand, in the soaking process in step S3 or step S5, the controller 30 first closes the second drain valve 22 while stopping the pump 12. As a result, the detergent solution supplied to the washing tub 4 from the circulation path 11 in the previous circulation process is accumulated in the washing tub 4, thus the detergent solution can easily immerse into the washings Q. Moreover, the controller 30 opens the second drain valve 22 at a timing in the final stage when a predetermined time has elapsed from the start of the soaking process. As a result, the detergent solution in the washing tub 4 is accumulated in the tank 21 through the drainage path 9, so that circulation of the detergent solution can be promptly started in the circulation process that is immediately performed.

[0070] When the predetermined time has elapsed (Yes in step S6) and the normal washing process is performed, the controller 30 closes the second drain valve 22 and opens the water supply valve 7 to supply water to the washing tub 4 along with the start of the normal washing process. In this case, the pump 12 is driven to transfer the detergent solution in the tank 21 to the washing tub 4 via the circulation path 11. In this way, by utilizing the detergent solution of the tank 21 for supplying water, water supplied from the water supply path 6 can be suppressed to be little.

[0071] As described above, in step S1 of supplying water in the circulation-soaking process, as a structure for supplying water containing the detergent without spraying the detergent solution on the washings Q directly, the discharge opening 6B of the water supply path 6 is provided as follows: as indicated by the arrow in thick solid line, the water containing the detergent is discharged toward the gap 19 between the outer tub 3 and the washing tub 4, that is, toward the position away from the washings Q in the washing tub 4. As a modification of this structure, a second modification and a third modification can be exemplified.

[0072] In the second modification shown in FIG. 5, the water supply path 6 passes through the detergent container 8, and extends to the lower side Z2 between the circumferential wall 3A of the outer tub 3 and the housing 2. Another end 6C of the water supply path 6 is connected to the lower end of the circumferential wall 3A. In this case, the water supply path 6 is a flow path outside the outer tub 3, and the discharge opening 6B at the end 6C faces the lower end of the gap 19 between the outer tub 3 and the washing tub 4 in the lateral direction Y. On the other hand, the washing machine 1 of the second modification includes a branch path 25 branched from the water supply path 6 in the detergent container 8. The branch path 25 is a flow path extending from the detergent container 8 to the lower side Z2. At the lower end of the branch path 25, a water supply port 25A facing the entrance 4D of the washing tub 4 from the upper side Z1 is provided. A water supply valve 26 is provided in the branch path 25. In the following description of the second modification, the water supply valve 7 is referred to as a first water supply valve 7, and the water supply valve 26 is referred to as a second water supply valve 26 for convenience. The opening and closing of the second water supply valve 26 are controlled by the controller 30.

[0073] In the circulation-soaking process in the second modification, when water is supplied in step S1, the controller 30 opens the first water supply valve 7 and closes the second water supply valve 26. As a result, the water from the faucet passes through the detergent container 8 to carry the detergent, flows down to reach the supply path 6, and then is supplied to a space 27 inside the outer tub 3 from the discharge opening 6B, as indicated by a thick solid arrow. The space 27 is closer to the lower side Z2 than the bottom wall 4B of the washing tub 3. At this time, the discharge opening 6B discharges the water flowing through the water supply path 6 toward the space 27, that is, the position away from the washings Q in the washing tub 4. As a result, the water containing the detergent is supplied without being sprayed on the washings Q directly. On the other hand, in the case of supplying water in the normal washing process performed after the circulation-soaking process, the controller 30 closes the first water supply valve 7 and opens the second water supply valve 26. As a result, the water from the faucet is directly supplied into the washing tub 4 from the water supply port 25A through the branch path 25. That is, the water supply path 6 is used to supply water initially, and the branch path 25 is used to supply water thereafter.

[0074] In the third modification shown in FIG. 6, the end 6C of the water supply path 6 passes through the entrance 3D of the outer tub 3, and the discharge opening 6B at the end 6C faces the entrance 4D of the washing tub 4 from the upper side Z1. In the washing machine 1 of the third modification, a guiding portion 28 is provided inside the washing tub 4. The guiding portion 28 is a groove extending in the up-down direction Z along the axis J over a range from the upper end to the lower end of the circumferential wall 4A of the washing tub 4, and the plan cross section thereof is configured in an arc shape curved toward the axis J side. The guiding portion 28 is fixed to the circumferential wall 4A so as to cover one circumferential portion of the circumferential wall 4A from the axis J side. As a result, a guide flow path 29 extending in the up-down direction Z is formed between the guiding portion 28 and the circumferential wall 4A. The upper end of the guiding portion 28 is a reception portion 28A formed in a bowl shape bulging toward the axis J. The guide flow path 29 is exposed from the reception portion 28A to the upper side Z1. The discharge opening 6B is opposed to the reception portion 28 A from the upper side Z1.

[0075] In the circulation-soaking process in the third modification, the controller 30 opens the water supply valve 7 when water is supplied in step S1. As a result, the water from the faucet passes through the detergent container 8 to carry the detergent, passes through the water supply path 6, and falls from the discharge opening 6B to the reception portion 28A of the guiding portion 28 as indicated by a thick solid arrow. The water received by the reception portion 28A flows down the guide path 29, is leaked from the through holes 4E of the washing tub 4 to the outside of the washing tub 4, and reaches the space 27 inside the outer tub 3 that is closer to the lower side Z2 than the bottom wall 4B of the washing tub 4. At this time, the discharge opening 6B discharges the water flowing through the water supply path 6 toward the guiding portion 28, that is, the position away from the washings Q in the washing tub 4. As a result, the water containing the detergent is supplied without being sprayed on the washings Q directly.

Claims

1. A washing machine, comprising:

a washing tub having an axis extending longitudinally, wherein the washing tub is configured to accommodate washings and is capable of storing water;

a circulation path configured to draw detergent solution mixed with a detergent in the washing tub and return the detergent solution into the washing tub from an upper side;

a pump configured to pump the detergent solution in the washing tub into the circulation path and allow the detergent solution to rise in the circulation path; and

an execution unit configured to execute a washing operation, wherein the washing operation comprises a circulation-soaking process during which a circulation process and a soaking process are conducted alternately and repeatedly, wherein the detergent solution is circulated between the washing tub and the circulation path by driving the pump and sprayed onto washings in the circulation process, and the pump is stopped from being driven and the washings are soaked with the detergent solution in the washing tub in the soaking process.

2. The washing machine according to claim 1, further comprising a motor for rotating the washing tub, wherein the execution unit is configured to drive the motor to rotate the washing tub at a low speed below a predetermined rotation speed in at least one circulation process.

3. The washing machine according to claim 1 or claim 2, further comprising a motor for rotating the washing tub, wherein the execution unit is configured to drive the motor to rotate the washing tub repeatedly an intermittently in at least one circulation process.

4. The washing machine according to any of claims 1 to 3, further comprising a motor for rotating the washing tub, during the circulation-soaking process, the execution unit is configured to cause the washing tub to stop in the circulation process, and drive the motor to rotate the washing tub merely for a predetermined angle prior to starting a next circulation process.

5. The washing machine according to any of claims 1 to 4, further comprising:

a water supply path configured to supply water to the washing tub, and

a water supply valve configured to open and close the water supply path,

wherein the washing operation comprises a washing process consisting of the circulation -soaking process and a normal washing process, in the normal washing process, water is accumulated in the washing tub to perform a normal washing of the washings after the circulation-soaking process, wherein

during the circulation-soaking process, the execution unit is configured to open the water supply valve, so as to supply a part of a total water supply amount in the whole washing process to the washing tub and generate the detergent solution.

6. The washing machine according to claim 5, further comprising a detergent container connected to the water supply path and containing the detergent, wherein the water supply path is provided with a discharge opening, and water flowing through the water supply path after passing through the detergent container is discharged from the discharge opening toward a position away from the washings in the washing tub.

7. The washing machine according to any of claims 1 to 6, wherein the execution unit is configured to change a time for performing the circulation process and a time for performing the soaking process according to load amount of the washings inside the washing tub.

Drawing