CN115151691A - Washing machine - Google Patents

Abstract

A washing machine comprising: a motor (6), a washing tub (8) having an outer tub (3) and an inner tub (4), a water discharge path (15) connected to a water discharge port (3G) of the outer tub (3), an overflow path (17) connected to an overflow port (3E) disposed at a position higher than the water discharge port (3G) in the outer tub (3), a water discharge valve (16) for opening and closing the water discharge path (15), a water supply valve (14) for supplying water into the washing tub (8), a water level detection unit for detecting a water level in the washing tub (8), and a microcomputer (21) for performing a washing operation. During the washing operation, the microcomputer (21) ends the rinsing process in a state where the drain valve (16) is closed, and during the tub cleaning process, raises the water level in the washing tub (8) to a tub cleaning water level (W3) which is higher than the overflow opening (3E) and lower than the opening (3D) of the outer tub (3) in a state where the drain valve (16) is continuously closed.

Description

Washing machine

Technical Field

The present invention relates to a washing machine.

Background

The washing machine described in patent document 1 includes: a water tub having a drain port formed at a bottom thereof; a drain hose connected to the drain port; a drain valve for opening and closing the drain hose; a rotating barrel accommodated in the water barrel in a longitudinal axis shape. The washing machine can perform a tub washing mode for washing the water tub and the rotary tub. In the tub rotation washing process in the tub washing mode, the rotation tub is rotated in a state where the drain valve is opened to continuously drain water from the water tub. Therefore, the water in the water bucket and the rotary bucket gradually rises to a water level without overflowing in a mortar shape. The water tub and the rotary tub are washed by the dehydration by the centrifugal force at this time and the water flow generated along with the rotation of the rotary tub.

Not only the washing machine of patent document 1, but also a biofilm formed by detergent residue and dirt (hereinafter, simply referred to as "dirt") remaining after a washing operation may be used as a nutrient in a washing tub of a general washing machine to generate mold. Since the biofilm is often generated in the vicinity of the water surface of the water stored in the washing tub during the washing operation, it is necessary to remove dirt at a high position in the washing tub in order to prevent the biofilm, i.e., mold, from being generated. However, in the case where water is always discharged from the lower water discharge port during the spin washing of the tub as in patent document 1, even if the spin tub is rotated, the water levels in the water tub and the spin tub hardly reach the dirt, and thus it is difficult to efficiently remove the dirt by the water flow. In addition, there is a fear that dirt, which is not easily removed and is caught in the water flow, may be re-attached to the water tub or the rotary tub as the water level is lowered due to the water discharge from the water discharge port.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2016-2263

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a washing machine capable of efficiently washing a washing tub.

Means for solving the problems

The present invention is a washing machine comprising: a motor generating a driving force; a washing tub having an outer tub which can store water, a drain port, a spillway port disposed at a position higher than the drain port, and an opening disposed at a position higher than the spillway port, and an inner tub which is disposed in the outer tub, rotates by receiving a driving force of the motor, is provided with a through hole for passing water between the inner tub and the outer tub, and an entrance facing the opening, and through which laundry is put in and out of the inner tub; a water discharge path connected to the water discharge port to discharge water in the washing tub; an overflow path connected to the overflow port to guide the water in the washing tub from the overflow port to the drainage path; a drain valve that opens and closes the drain path; a water supply part supplying water into the washing tub; a water level detecting part for detecting the water level in the washing tub; and a control part controlling the motor, the drain valve, and the water supply part, a detection result of the water level detection part being input to the control part, the control part performing a washing operation having a washing process of supplying water into the washing tub through the water supply part and washing laundry in the inner tub, a rinsing process of supplying water into the washing tub through the water supply part and rinsing the laundry in the inner tub after the washing process, and a tub washing process of washing the washing tub after the rinsing process, wherein the control part ends the rinsing process in a state where the drain valve is closed and water is stored in the washing tub, and rotates the inner tub through the motor in a state where the drain valve is continuously closed in the tub washing process, thereby raising a water level in the washing tub above the overflow port and below the open tub washing.

Further, the present invention is characterized in that the control part reduces the rotation speed of the motor when the water level inside the washing tub exceeds the tub washing water level during the tub washing process.

Further, the present invention is characterized in that the control part performs the tub washing process a plurality of times, the control part performs a drain process of opening the drain valve to drain a part of the water in the washing tub at least at a final stage of a first tub washing process, and the control part makes a maximum rotation speed of the motor in the tub washing processes after a second time higher than a maximum rotation speed of the motor in the tub washing process at the first time.

In addition, the present invention is characterized in that the control unit continuously rotates the motor during the drainage treatment.

In addition, the washing machine may include a receiving unit that receives a selection of a type of laundry, and the control unit may control at least one of a maximum rotation speed of the motor during the tub washing process and a water level in the tub at a start of the tub washing process to be lower than a case of laundry other than the carpet when the laundry related to the selection received by the receiving unit is the carpet.

Effects of the invention

According to the present invention, in a washing machine having an outer tub and an inner tub inside the outer tub, water supplied by water supply from a water supply unit is passed between the outer tub and the inner tub through a through hole of the inner tub, and is thereby stored in the outer tub and the inner tub, i.e., the entire washing tub. When the drain valve opens the drain path, water in the washing tub is drained from the drain port of the outer tub through the drain path. When the water level in the washing tub rises to the overflow port disposed at a position higher than the drain port in the outer tub, water on the water surface side, i.e., the upper side, in the washing tub is guided from the overflow port to the drain passage through the overflow passage and discharged through the drain passage. The washings enter and exit the inner barrel through an opening arranged at a position higher than the overflow port in the outer barrel and the inlet and outlet of the inner barrel.

As a part of the washing operation, the control part of the washing machine performs a tub washing process of washing the washing tub after the rinsing process. Specifically, the control unit ends the rinsing process in a state where the drain valve is closed and the washing tub stores water, and rotates the inner tub by the motor in a state where the drain valve is continuously closed and the washing tub stores water in the subsequent tub washing process, thereby raising the water level in the washing tub to a tub washing water level higher than the overflow port and lower than the opening of the outer tub by a centrifugal force generated along with the rotation of the inner tub. When the inner tub is rotated so as not to discharge water halfway, a water flow generated by water rising to a tub washing water level in the washing tub reaches dirt in the washing tub at a height above the overflow port so as not to leak out of the washing tub from the opening. Therefore, the dirt in the washing tub can be removed by such water flow and centrifugal force. The removed dirt is guided to the drainage path from the overflow port through the overflow path together with the water on the water surface side in the washing tub and discharged, so that the dirt can be prevented from adhering to the washing tub again. Through such a tub washing process, the washing tub can be effectively washed.

Further, according to the present invention, the control part reduces the rotation speed of the motor when the water level inside the washing tub exceeds the tub washing water level during the tub washing process, whereby the water inside the washing tub can be prevented from leaking out of the washing tub from the opening of the outer tub.

Further, according to the present invention, in case that the tub washing process is performed a plurality of times, the control part drains a part of the water inside the washing tub by performing the drainage process at least at the last stage of the first tub washing process. The control unit increases the maximum rotational speed of the motor in the second and subsequent tub washing processes to be higher than the maximum rotational speed of the motor in the first tub washing process. In this case, during the second and subsequent tub washing processes, a small amount of water may be further pushed up by the centrifugal force generated by the high rotation of the inner tub, and thus, the tub washing water level becomes higher than that during the first tub washing process. Therefore, in the second and subsequent washing processes of the tub, the dirt in the vicinity of the opening among the dirt at the position higher than the level of the overflow port in the washing tub can be removed without fail. By such a multi-tub washing process, the washing tub can be washed more efficiently.

Further, according to the present invention, since the control part continuously generates the water current by continuously rotating the motor during the drainage process between the plurality of tub washing processes, the dirt removed from the washing tub is caught in the water current, and thus, the dirt can be prevented from being re-attached to the washing tub.

Further, according to the present invention, in the case where the felt having a high water absorbability is used as the laundry, the control unit lowers at least one of the maximum rotation speed of the motor during the tub washing process and the water level in the washing tub at the start of the tub washing process, as compared with the case where the laundry other than the felt is used. Thereby, it is possible to prevent the water level in the washing tub from rising sharply and the water in the washing tub from leaking out of the washing tub from the opening of the outer tub during the tub washing process in the washing operation with respect to the felt.

Drawings

Fig. 1 is a schematic longitudinal sectional view of a washing machine according to an embodiment of the present invention.

Fig. 2 is a block diagram showing an electrical structure of the washing machine.

Fig. 3 is a flowchart showing a washing operation performed in the washing machine.

Fig. 4 is a flowchart illustrating a tub washing process in a washing operation.

Fig. 5 is a time chart showing a multi-tub washing process performed continuously.

Description of the reference numerals

1: a washing machine; 3: an outer tub; 3D: an opening; 3E: an overflow port; 3G: a water outlet; 4: an inner barrel; 4D: an entrance and an exit; 4E: a through hole; 6: a motor; 8: a washing tub; 11: a display operation unit; 13: a water supply path; 14: a water supply valve; 15: a water drainage path; 16: a drain valve; 17: an overflow path; 21: a microcomputer; 28: a water level detection unit; q: washing the articles; w3: the tub cleans the water level.

Detailed Description

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. Fig. 1 is a schematic longitudinal sectional view of a washing machine 1 according to an embodiment of the present invention. The vertical direction in fig. 1 is referred to as a vertical direction Z of the washing machine 1, and the upper side and the lower side in the vertical direction Z are referred to as an upper side Z1 and a lower side Z2, respectively. The washing machine 1 includes: a cabinet 2 constituting a housing of the washing machine 1; an outer tub 3 disposed in the cabinet 2; an inner tub 4 housed in the outer tub 3; a pulsator 5 which is an example of a rotary blade disposed in the inner tub 4; a motor 6 for generating a driving force for rotating the inner tub 4 and the pulsator 5; and a clutch 7, which is an example of a switching unit that switches a transmission destination of the driving force of the motor 6. The combination of the outer tub 3 and the inner tub 4 is referred to as a washing tub 8.

The case 2 is made of, for example, metal and is formed in a box shape. An opening 2B for communicating the inside and outside of the case 2 is formed in the upper surface 2A of the case 2. A door 10 for opening and closing the opening 2B is provided on the upper surface 2A. A display operation portion 11 formed of a liquid crystal operation panel or the like is provided around the opening 2B of the upper surface 2A. The user of the washing machine 1 can select an operation condition related to the washing operation performed in the washing machine 1 or instruct the washing machine 1 to start or stop the washing operation by operating the display operation unit 11. The display operation unit 11 displays information for the user.

The outer tub 3 is made of, for example, resin and is formed in a bottomed cylindrical shape. The outer tub 3 has: a substantially cylindrical circumferential wall 3A disposed along the vertical direction Z; a bottom wall 3B that closes the hollow portion of the circumferential wall 3A from the lower side Z2; and an annular wall 3C that protrudes toward the center of the circumferential wall 3A along the upper end edge of the circumferential wall 3A. Inside the annular wall 3C, an opening 3D communicating with the hollow portion of the circumferential wall 3A from the upper side Z1 is provided. The opening 3D faces and communicates with the opening 2B of the case 2 from the lower side Z2. The annular wall 3C may be provided with a door 12 for opening and closing the opening 3D. A weir 3E penetrating the circumferential wall 3A in the radial direction is provided at the upper part of the circumferential wall 3A. The bottom wall 3B is formed in a substantially horizontally extending disc shape, and a through hole 3F penetrating the bottom wall 3B is provided at a center position of the bottom wall 3B. A drain port 3G is provided in the bottom wall 3B at a position avoiding the through hole 3F. The overflow 3E is disposed at a position higher than the drain 3G in the tub 3, and the opening 3D is disposed at a position higher than the overflow 3E in the tub 3.

A water supply path 13 connected to a tap of tap water is connected to the annular wall 3C of the tub 3 from the upper side Z1. A water supply valve 14 is provided in the middle of the water supply path 13. The water supply valve 14 is constituted by, for example, an electromagnetic valve. A drain passage 15 is connected to the drain port 3G of the bottom wall 3B of the tub 3 from the lower side Z2. The drain passage 15 is led out of the washing machine 1, i.e., out of the machine. A drain valve 16 is provided in the middle of the drain passage 15. The water discharge valve 16 is opened and closed by a torque motor (not shown), for example. The water supply valve 14, which is opened and activated, opens the entire water supply path 13 by opening a middle portion of the water supply path 13. The water supply valve 14, which is closed and in an inoperative state, blocks a middle portion of the water supply path 13 to cut off the water supply path 13 in the middle. The drain valve 16, which is opened and in an operating state, opens the entire drain passage 15 by opening a middle portion of the drain passage 15. The drain valve 16, which is closed and in an inactive state, blocks the middle of the drain passage 15, thereby shutting off the drain passage 15.

When the water supply valve 14 is opened in a state where the drain valve 16 is closed, water is supplied from the water supply path 13 into the outer tub 3 to store water in the outer tub 3. The water supply path 13 and the water supply valve 14 function as an example of a water supply unit for supplying water into the tub 3, that is, the washing tub 8. When the water supply valve 14 is closed, the water supply is stopped. When the drain valve 16 is opened, the water in the outer tub 3 is drained from the drain port 3G to the outside of the machine through the drain passage 15. The washing machine 1 further comprises an overflow passage 17 having one end 17A connected to the overflow 3E of the circumferential wall 3A and the other end 17B connected to a downstream portion of the drain passage 15 which is further from the drain opening 3G than the drain valve 16.

The inner tub 4 is made of, for example, metal, is formed in a bottomed cylindrical shape smaller than the outer tub 3 by one turn, and can accommodate the laundry Q therein. The inner tub 4 is coaxially disposed in the outer tub 3. The inner tub 4 accommodated in the outer tub 3 is rotatable about an axis J constituting a central axis thereof and extending in the vertical direction Z. The washing machine 1 having the inner tub 4, i.e., the washing tub 8, arranged vertically as described above is a vertical washing machine. The inner barrel 4 has: a substantially cylindrical circumferential wall 4A disposed along the vertical direction Z; a bottom wall 4B that closes the hollow portion of the circumferential wall 4A from the lower side Z2; and an annular wall 4C projecting toward the axis J along the upper end edge of the circumferential wall 4A. The radial direction is a radial direction R with respect to the axis J.

The inner circumferential surface of the circumferential wall 4A is the inner circumferential surface of the inner barrel 4. The circumferential wall 4A is in a state of being surrounded by the circumferential wall 3A of the outer tub 3. The bottom wall 4B is provided at the lower end of the inner barrel 4. The annular wall 4C faces the annular wall 3C of the tub 3 from the lower side Z2. An inlet/outlet 4D is provided inside the annular wall 4C. The inlet/outlet 4D is positioned at the upper end of the inner tub 4 so that the hollow portion of the circumferential wall 4A is exposed upward Z1. The inlet/outlet 4D faces and communicates with the opening 3D of the tub 3 from the lower side Z2. The user puts in and takes out the laundry Q into and from the upper side Z1 of the inner tub 4 through the opened opening 2B, the opening 3D, and the doorway 4D.

The circumferential wall 4A and the bottom wall 4B of the inner barrel 4 are provided with a plurality of through holes 4E, and water in the outer barrel 3 flows between the outer barrel 3 and the inner barrel 4 through the through holes 4E and is stored in the inner barrel 4. Therefore, water is accumulated in the outer tub 3 and the inner tub 4, i.e., the entire washing tub 8, and the water level in the outer tub 3 is identical to the water level in the inner tub 4. The circumferential wall 4A may not be provided with the through-holes 4E, and only the bottom wall 4B may be provided with the through-holes 4E.

The bottom wall 4B of the inner tub 4 is formed in a disc shape and extends substantially parallel to the bottom wall 3B of the outer tub 3 at an interval on the upper side Z1. A through hole 4F penetrating the bottom wall 4B is provided at a center position of the bottom wall 4B coinciding with the axis J. The bottom wall 4B is provided with a tubular support shaft 18 that surrounds the through hole 4F and extends downward Z2 along the axis J. The support shaft 18 is inserted through the through hole 3F of the bottom wall 3B of the tub 3, and the lower end of the support shaft 18 is located below the bottom wall 3B by Z2.

The pulsator 5 is formed in a disk shape with the axis J as a center, and is disposed on the bottom wall 4B in the inner tub 4. A plurality of blades 5A are provided on the upper surface of the pulsator 5 facing the inlet/outlet 4D of the inner tub 4 in a radial arrangement. The pulsator 5 is provided with a rotating shaft 19 extending from the center thereof to the lower side Z2 along the axis J. The rotation shaft 19 is inserted through the hollow portion of the support shaft 18, and the lower end portion of the rotation shaft 19 is located below the bottom wall 3B of the outer tub 3 by Z2.

The motor 6 is an electric motor such as a variable frequency motor. The motor 6 is disposed on the lower side Z2 of the tub 3 in the casing 2. The motor 6 has an output shaft 20 that rotates about the axis J, and the generated driving force is output from the output shaft 20.

The clutch 7 is interposed between the lower end portions of the support shaft 18 and the rotary shaft 19 and the upper end portion of the output shaft 20 protruding upward Z1 from the motor 6. The clutch 7 selectively transmits the driving force output from the output shaft 20 of the motor 6 to one or both of the support shaft 18 and the rotary shaft 19. When the driving force from the motor 6 is transmitted to the support shaft 18, the inner tub 4 receives the driving force of the motor 6 and rotates about the axis J. When the driving force from the motor 6 is transmitted to the rotary shaft 19, the pulsator 5 receives the driving force of the motor 6 and rotates about the axis J. The clutch 7 is a known electric transmission mechanism. The torque motor (not shown) may operate the clutch 7.

Fig. 2 is a block diagram showing an electrical configuration of the washing machine 1. The washing machine 1 includes a microcomputer 21 as an example of a water supply part and a control part. The microcomputer 21 is built in the case 2, and includes, for example, a CPU (central processing unit) 22; a memory 23 such as a ROM (read only memory) or a RAM (random access memory); and a timer 24 (see fig. 1) for timing.

The motor 6, the clutch 7, the water supply valve 14, and the drain valve 16 are electrically connected to the microcomputer 21 via, for example, a drive circuit 25, and the display operation unit 11 is also electrically connected to the microcomputer 21. The microcomputer 21 operates the motor 6 to drive it or stops the motor 6 without operating it. The microcomputer 21 can also control the rotation direction of the motor 6. Thus, the motor 6 can rotate forward or backward. The microcomputer 21 controls the clutch 7 to switch a transmission target of the driving force of the motor 6 to one or both of the inner tub 4 and the pulsator 5. The microcomputer 21 controls opening and closing, i.e., operation/non-operation, of the water supply valve 14 and the water discharge valve 16. When the user operates the display operation unit 11 to select an operation condition or the like, the microcomputer 21 receives the selection. The microcomputer 21 controls the display contents of the display operation unit 11.

The washing machine 1 further includes a buzzer 26, a rotation speed reading device 27, and a water level detecting part 28 electrically connected to the microcomputer 21. The microcomputer 21 generates a predetermined sound by the buzzer 26, and notifies the user of the start and end of the washing operation.

The rotation speed reading device 27 is a device that reads the rotation speed of the motor 6, strictly speaking, the rotation speed of the output shaft 20 of the motor 6, and is constituted by, for example, a hall IC. The rotation speed read by the rotation speed reading device 27 is input to the microcomputer 21 in real time. The microcomputer 21 controls the duty ratio of the voltage applied to the motor 6 based on the input rotation speed, thereby controlling the motor 6 to rotate at a desired rotation speed. The rotation speed of the inner tub 4 and the pulsator 5 may be the same as the rotation speed of the motor 6, or may be a value obtained by multiplying the rotation speed of the motor 6 by a predetermined constant such as a reduction ratio of the clutch 7.

The water level detector 28 is a water level sensor for detecting the water level in the tub 3, i.e., the water level in the washing tub 8. As an example of water level detecting unit 28, a pressure type water level sensor that detects the water level in washing tub 8 based on the pressure in washing tub 8 may be used. The water level of the water stored in washing tub 8 is not necessarily horizontal over the entire area, and water level detecting unit 28 detects the highest water level on the water surface as the current water level in washing tub 8. The current water level in the washing tub 8, that is, the detection result of the water level detecting part 28 is inputted to the microcomputer 21.

The microcomputer 21 performs a washing operation by controlling the operations of the motor 6, the clutch 7, the water supply valve 14, and the drain valve 16. The washing operation at least comprises: a washing process of supplying water into the washing tub 8 and washing the laundry Q in the inner tub 4 by opening the water supply valve 14; a rinsing process of supplying water into the washing tub 8 and rinsing the laundry Q in the inner tub 4 by opening the water supply valve 14 after the washing process; and a tub washing process of washing the washing tub 8 after the rinsing process. In the present embodiment, two rinsing processes are performed, the first rinsing process is referred to as a first rinsing process, and the second rinsing process is referred to as a second rinsing process. The washing operation in the present embodiment also includes a dehydration process for dehydrating the laundry Q by rotating the inner tub 4. The dehydration process comprises the following steps: an intermediate dehydration process, which is executed in the middle of the washing operation; and a final dehydration process, which is performed at the end of the washing operation. It should be noted that the washing machine 1 may be a washing and drying all-in-one machine that performs a drying process for drying the laundry Q after the dehydration process.

When the user puts the laundry Q into the inner tub 4 and instructs the start of the washing operation, the microcomputer 21 starts the washing operation. The user may put the detergent into the inner tub 4 before and after putting the laundry Q. Referring to the flowchart of fig. 3, first, the microcomputer 21 detects the load amount, which is the amount of the laundry Q in the inner tub 4 (step S1). As an example of the load amount detection, the microcomputer 21 detects the load amount from the fluctuation of the rotation speed of the motor 6 when the inner tub 4 is rotated stably at a low speed. The microcomputer 21 determines a washing water level W1 (refer to fig. 1) which is a water level of water stored in the washing tub 8 to be supplied next based on the previously detected load amount. The relationship between the washing water level W1 and the load amount is determined in advance by an experiment or the like and stored in the memory 23.

Then, as a water supply process of one cycle of the washing process, the microcomputer 21 continuously opens the water supply valve 14 to supply water into the washing tub 8 (step S2). Since the drain valve 16 is in a closed state, the water level in the washing tub 8 rises. When the water level in the washing tub 8 rises to the previously determined washing water level W1, the microcomputer 21 stops the supply of water by closing the water supply valve 14. Thereby, the water supply process is ended.

Next, the microcomputer 21 executes the agitation process in a state where water is stored in the washing tub 8. Specifically, the microcomputer 21 switches the clutch 7 as necessary to transmit the driving force of the motor 6 to the pulsator 5, and then rotates the pulsator 5 by driving the motor 6 (step S3). The pulsator 5 can continuously rotate in the same direction, but in the present embodiment, the pulsator 5 rotates in reverse alternately repeating normal rotation and reverse rotation every 1 second to 2 seconds by intermittent driving of the motor 6. In the agitation process, the laundry Q in the inner tub 4 is agitated and washed by the counter-rotating pulsator 5. In the water supply process of step S2, the pulsator 5 may also rotate, so that the detergent is easily dissolved in the water. The dirt of the laundry Q is decomposed by the detergent dissolved in water. When the predetermined stirring time has elapsed, the microcomputer 21 ends the stirring process. Thereby, the washing process is ended.

After the washing process, as an intermediate dehydration process, the microcomputer 21 rotates the inner tub 4 at a high speed in a state where the drain valve 16 is opened (step S4). The laundry Q in the inner tub 4 is dehydrated by the centrifugal force generated by the high-speed rotation. The water seeped out of the laundry Q by the dehydration is discharged to the outside of the machine through the drainage passage 15. At the final stage of the intermediate spinning course, the microcomputer 21 switches the clutch 7 so that the driving force of the motor 6 is not transmitted to the inner tub 4 and stops the motor 6, and thus the inner tub 4 is inertially rotated. At the end of the intermediate dehydration process, the microcomputer 21 closes the water discharge valve 16.

Next, as a first rinsing process, the microcomputer 21 performs spray rinsing (step S5). Specifically, the microcomputer 21 showers the water supply into the inner tub 4 by intermittently opening the water supply valve 14 in a state where the water discharge valve 16 is closed. In this state, the microcomputer 21 rotates the inner tub 4 at a low speed of, for example, 30rpm so as to spray water over the corners of the laundry Q. Thereby, the laundry Q in the inner tub 4 is rinsed without dead space. After that, the microcomputer 21 performs the same intermediate dehydration process as the step S4 (step S6). Each intermediate dehydration process may be regarded as a part of the rinsing process performed immediately after the intermediate dehydration process.

Next, the microcomputer 21 performs a second rinsing process. The contents of the second rinsing process are substantially the same as the washing process except for the point that no detergent is present. Specifically, the microcomputer 21 supplies water in the same manner as in step S2 (step S7), and then performs agitation rinsing of the laundry Q in the same manner as in step S3 (step S8). After that, when the prescribed agitation time has elapsed, the microcomputer 21 stops the motor 6 in a state where the drain valve 16 is closed and water is stored in the washing tub 8, thereby ending the second rinsing process.

Next, the microcomputer 21 performs the tub washing process (step S9), and finally, the microcomputer 21 performs the final dehydrating process (step S10) similar to the intermediate dehydrating process. However, the rotation condition of the inner tub 4 may be different between the intermediate dehydration process and the final dehydration process, and particularly, the maximum rotation speed of the inner tub 4 in the final dehydration process is higher than that of the inner tub 4 in the intermediate dehydration process. The washing operation is ended as the final dehydration process is ended.

Next, the tub washing process of step S9 will be described with reference to the flowchart of fig. 4. Regarding the tub washing process, the water level inside the washing tub 8 exists, in addition to the above-described washing water level W1: an overflow water level W2 having the same height as the overflow port 3E of the outer tub 3; a tub washing water level W3 which is higher than the overflow water level W2 and lower than the opening 3D of the outer tub 3; and an abnormal water level W4 higher than the tub washing water level W3 (see fig. 1). The overflow water level W2 is higher than the wash water level W1 and is set at the same height as the lower end 3H of the overflow 3E in the present embodiment. The tub washing water level W3 may not be a fixed water level, and may vary between the overflow water level W2 and the abnormal water level W4. The abnormal water level W4 is set to be lower than the opening 3D of the tub 3 to some extent. In addition, the water supply valve 14 is always in a closed state during the tub washing process.

At the beginning of the tub washing process, the microcomputer 21 switches the clutch 7 to transmit the driving force of the motor 6 to the inner tub 4 (step S11). Next, the microcomputer 21 confirms the current water level in the washing tub 8 (step S12). If the water level in the washing tub 8 is not lower than the washing water level W1 (no in step S12), the microcomputer 21 lowers the water level in the washing tub 8 by opening the drain valve 16 to drain the inner tub 4 (step S13).

If the water level in the washing tub 8 is lower than the washing water level W1 (yes in step S12), at the timing t0, the microcomputer 21 starts the rotation of the inner tub 4 by operating the motor 6 in a state that the drainage valve 16 is continuously closed (step S14). Then, a vortex is generated in the washing tub 8 by a centrifugal force generated by the rotation of the inner tub 4, and the water surface S in the washing tub 8 is bent in a U-shape such that a central portion on the inner side in the radial direction R, which is the axis J side, becomes lower and an outer peripheral portion on the outer side in the radial direction R becomes higher as shown by a two-dot chain line in fig. 1. Thereby, the water level in the washing tub 8 sequentially exceeds the washing water level W1 and the overflow water level W2 to rise to the tub washing water level W3. Then, the water on the upper side Z1, which is the water surface S side in the washing tub 8, is guided from the overflow port 3E to the drainage channel 15 through the overflow channel 17 and is discharged to the outside of the machine through the drainage channel 15.

When the water level in the washing tub 8 exceeds the tub washing water level W3 to reach the abnormal water level W4 during the tub washing process (yes in step S15), the microcomputer 21 lowers the water level in the washing tub 8 by lowering the rotation speed of the motor 6 (step S16). This prevents water in the washing tub 8 from leaking out of the washing tub 8 through the opening 3D of the outer tub 3.

When the predetermined time t1 has elapsed from the rotation start timing t0 of the motor 6 in step S14 (yes in step S17) in a state where the water level in the washing tub 8 is lower than the abnormal water level W4 (no in step S15), the microcomputer 21 confirms the water level in the washing tub 8 (step S18). If the water level in the washing tub 8 is lower than the overflow water level W2 (yes in step S18), the microcomputer 21 raises the water level in the washing tub 8 by increasing the rotation speed of the motor 6 (step S19). If the water level in the washing tub 8 is the overflow water level W2 (no in step S18), the microcomputer 21 maintains the water level in the washing tub 8 at the overflow water level W2 by maintaining the rotation speed of the motor 6 (step S20).

The rotation speed of the motor 6 in a state where the water level in the washing tub 8 is maintained at the overflow water level W2 is the maximum rotation speed in the tub washing process. The maximum rotation speed is set to a rotation speed lower than the resonance point of the washing machine 1, for example, 240rpm or less. In the present embodiment, the maximum rotation speed when the water level in the washing tub 8 reaches the overflow water level W2 smoothly is 120rpm, and the maximum rotation speed when the rotation speed of the motor 6 is increased after the predetermined time t1 (step S19) is 150rpm. The maximum rotation speed in the case where the rotation speed of the motor 6 is reduced (step S16) by the water level in the washing tub 8 reaching the abnormal water level W4 is 70rpm.

When the inner tub 4 is rotated without draining water halfway, the water flow generated by the water in the washing tub 8 rising to the tub washing water level W3 reaches the dirt in the washing tub 8 at a height above the lower end 3H of the overflow 3E, and does not leak out of the washing tub 8 through the opening 3D. The dirt at a height position equal to or higher than the lower end 3H is present on the upper portion of the inner peripheral surface of the circumferential wall 3A of the outer tub 3, the upper portion of the outer peripheral surface of the circumferential wall 4A of the inner tub 4, and the like. Therefore, the dirt particularly above the weirs 3E can be removed without fail by the water flow and the centrifugal force. The dirt removed together with the water on the water surface S side in the washing tub 8 is guided from the overflow gate 3E to the drainage channel 15 through the overflow channel 17 and discharged, so that the dirt can be prevented from adhering to the washing tub 8 again. Through such a tub washing process, the washing tub 8 can be effectively washed. In addition, the tub washing process is performed every washing operation, and thus the washing tub 8 can be maintained in a clean state for a long time.

Before starting the washing operation, the user can select the type of the laundry Q by operating the display operation unit 11. The microcomputer 21 and the display operation unit 11 function as an example of a receiving unit to receive selection of the type of laundry Q. When the laundry Q related to the selection received by the microcomputer 21 is the felt, the microcomputer 21 lowers at least one of the maximum rotation speed of the motor 6 during the tub washing process and the water level W1, which is the water level in the washing tub 8 at the start of the tub washing process, as compared with the case of the laundry other than the felt. Thus, during the tub washing operation of the blanket as the washing material Q having high water absorption, the water level in the washing tub 8 is prevented from rapidly rising to the abnormal water level W4 and the water in the washing tub 8 is prevented from leaking out of the washing tub 8 from the opening 3D of the outer tub 3.

When a predetermined time t2 of, for example, 10 to 20 seconds has elapsed from the rotation start timing t0 of the motor 6 in step S14 (yes in step S21), the microcomputer 21 opens the drain valve 16 to discharge the water in the washing tub 8 as the drain processing in the final stage of the tub washing process (step S22). The microcomputer 21 continues the rotation of the motor 6 at, for example, 30rpm in the water discharge process of step S22. As a result, since water flow continues to be generated in washing tub 8 even during the drainage process, dirt removed from washing tub 8 is caught in the water flow, and thus, it is possible to prevent dirt from adhering to washing tub 8 again. Then, the microcomputer 21 stops the motor 6 (step S23), ending the tub washing process.

The microcomputer 21 may also perform the tub washing process a plurality of times. Fig. 5 is a time chart in the case where the tub washing process is performed twice. In the time chart of fig. 5, the horizontal axis represents elapsed time, and the vertical axis shows the water level in the washing tub 8, the rotation speed of the motor 6, and the operation/non-operation state of the drain valve 16, which are the detection results of the water level detection unit 28, in order from the top. Note that t0', t1', t2', W1', and W3' in the second-time tub cleaning process in fig. 5 correspond to t0, t1, t2, W1, and W3 described above in the first-time tub cleaning process, respectively.

The microcomputer 21 opens the drain valve 16 to drain a part of the water within the washing tub 8 at least in the drain process (step S22) at the last stage of the first tub washing process. The microcomputer 21 increases the maximum rotational speed of the motor 6 in the second and subsequent tub washing processes to be higher than the maximum rotational speed of the motor 6 in the first tub washing process. As an example, the maximum rotation speed of the motor 6 in the first tub washing process is 70rpm, and the maximum rotation speed of the motor 6 in the second and subsequent tub washing processes is 120rpm.

In this case, during the second and subsequent tub washing processes, a small amount of water may be further pushed up by the centrifugal force generated by the high rotation of the inner tub 4, and thus the tub washing water level W3' becomes higher than the tub washing water level W3 during the first tub washing process. Therefore, in the second and subsequent tub washing processes, among the dirt in the washing tub 8 at a height equal to or higher than the lower end 3H of the overflow 3E, the dirt near the opening 3D can be removed without fail. By such a plurality of tub washing processes, the washing tub 8 can be washed more efficiently. In the drain process (step S22) at the final stage of the final tub washing process, the water in the washing tub 8 is drained until the water level in the washing tub 8 becomes zero.

The present invention is not limited to the embodiments described above, and various modifications can be made within the scope described in the claims.

For example, the axis J of the inner tub 4 in the washing machine 1 is disposed so as to extend vertically in the vertical direction Z in the above-described embodiment (see fig. 1), but the washing machine 1 as a vertical washing machine may include a configuration in which the axis J is disposed so as to be slightly inclined with respect to the vertical direction Z.

Claims (5)

1. A washing machine, characterized by comprising:

a motor generating a driving force;

a washing tub having an outer tub which can store water, a drain port, a spillway port disposed at a position higher than the drain port, and an opening disposed at a position higher than the spillway port, and an inner tub which is disposed in the outer tub, rotates by receiving a driving force of the motor, is provided with a through hole for passing water between the inner tub and the outer tub, and an entrance facing the opening, and through which laundry is put in and out of the inner tub;

a water discharge path connected to the water discharge port to discharge water in the washing tub;

an overflow path connected to the overflow port to guide the water in the washing tub from the overflow port to the drainage path;

a drain valve that opens and closes the drain path;

a water supply part supplying water into the washing tub;

a water level detecting part for detecting the water level in the washing tub; and

a control part controlling the motor, the drain valve, and the water supply part, a detection result of the water level detection part being input to the control part, the control part performing a washing operation having a washing process of supplying water into the washing tub through the water supply part and washing laundry in the inner tub, a rinsing process of supplying water into the washing tub through the water supply part and rinsing the laundry in the inner tub after the washing process, and a tub washing process of washing the washing tub after the rinsing process,

the controller may end the rinsing process in a state where the drain valve is closed and water is stored in the washing tub, and rotate the inner tub by the motor in a state where the drain valve is continuously closed during the tub washing process, thereby raising a water level in the washing tub to a level higher than the overflow port and lower than the open tub washing water level.

2. The washing machine as claimed in claim 1,

the control part reduces the rotation speed of the motor when the water level in the washing tub exceeds the tub washing water level during the tub washing process.

3. Washing machine according to claim 1 or 2,

the control part performs the tub washing process a plurality of times,

the control part performs a drain process of opening the drain valve to drain a part of water within the washing tub at least at a last stage of the first tub washing process,

the control part makes the maximum rotation speed of the motor in the second and later barrel washing processes higher than the maximum rotation speed of the motor in the first barrel washing process.

4. A washing machine according to claim 3,

the control unit continues the motor during the drainage process.

5. A washing machine according to any one of claims 1 to 4,

the washing machine includes a receiving part receiving a selection regarding a kind of laundry,

when the laundry related to the selection received by the receiving unit is the carpet, the control unit lowers at least one of the maximum rotation speed of the motor during the tub washing process and the water level in the washing tub at the start of the tub washing process, as compared with a case of laundry other than the carpet.

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