Top-loading washing machine

Abstract

To provide a top-loading washing machine which can materialize improvement in water saving and washing performance regarding processing of sprinkling water to laundry from the upper side.SOLUTION: A top-loading washing machine 1 includes: a washing tub 8 including an outer tub 3 in which an overflow port 3D is provided and an inner tub 4 arranged inside the outer tub 3; a drainage passage 16 for draining the water in the washing tub 8; an overflow passage 21 guiding the water in the washing tub 8 to the drainage passage 16 from the overflow port 3D; a water stop valve 22 opening / closing the overflow passage 21; and a microcomputer 25. The microcomputer 25 executes tub rotation processing, at least at any one of a washing step and a rinsing step after the washing step, in which, by rotating the inner tub 4 while water is stored in the washing tub 8, the water in the washing tub 8 is raised between the outer tub 3 and the inner tub 4 and is sprinkled on laundry Q in the inner tub 4 from an entrance 4D of the inner tub 4, and during the rotation of the inner tub 4 in the tub rotation processing, the overflow passage 21 is brought into a closed state by the water stop valve 22.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a top-loading washing machine. [Background technology]

[0002] The vertical washing machine described in Patent Document 1 below includes an outer tub that stores water, a washing tub that is disposed in the outer tub and stores laundry, and a motor that rotates the washing tub. In the vertical washing machine, a tub rotation process is performed in either the washing process or the rinsing process after the washing process. In the tub rotation process, the washing tub that stores water rotates, and the water in the outer tub rises between the outer tub and the washing tub and is sprayed onto the laundry in the washing tub from an inlet and outlet at the top end of the washing tub. By spraying water from above in this way, the laundry on the inlet and outlet side can also be washed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-5794 A Summary of the Invention [Problem to be solved by the invention]

[0004] Although not disclosed in Patent Document 1, in a typical vertical washing machine, an overflow port is provided at the top of the outer tub, and an overflow channel is connected to the overflow port. Water that rises to the overflow port in the outer tub flows from the overflow port through the overflow channel and is discharged outside the machine. In the washing process and rinsing process, a water supply process is performed at the beginning to accumulate water in the outer tub to a relatively high water level, so if a tub rotation process is performed in the first half immediately after the water supply process, some of the water that rises according to the rotation of the washing tub is wasted and discharged from the overflow port without being used for watering. Therefore, when water saving is important, the tub rotation process cannot be performed in the first half of the washing process and rinsing process after the water supply process, and can only be performed in the second half of the process when the water level has dropped to a certain extent due to washing, rinsing, etc. In other words, the presence of the overflow port restricts the timing of the tub rotation process. In the tub rotation process executed in the latter stage, the amount of water sprayed from above into the washing tub, i.e., the amount of water sprayed, is small, so there is a limit to the improvement of washing performance.

[0005] The present invention has been made under such circumstances, and has an object to provide a vertical washing machine that can save water and improve washing performance in the process of spraying water onto laundry from above. [Means for solving the problem]

[0006] The present invention relates to a washing tub having a drive unit that generates torque, an outer tub provided with a drain outlet, an overflow outlet located at a position higher than the drain outlet, and an opening located at a position higher than the overflow outlet and configured to store water, an inner tub that is disposed within the outer tub and configured with a through hole for passing water between the outer tub and the inner tub and an inlet / outlet facing the opening from below, laundry being inserted / removed via the opening and the inlet / outlet, and that rotates by receiving torque from the drive unit, a drain channel connected to the drain outlet and discharging water from within the washing tub, a drain valve that opens / closes the drain channel, and a drain valve connected to the overflow outlet and configured with a through hole for passing water between the outer tub and the inner tub and an inlet / outlet facing the opening from below, the inner tub being disposed within the outer tub and rotating by receiving torque from the drive unit, This vertical washing machine includes an overflow channel that guides water from the overflow outlet to the drain channel, a stop valve that opens and closes the overflow channel, and a control unit that executes a tub rotation process in which, during at least one of a washing process and a rinsing process after the washing process, the drain channel is closed by the drain valve and water is stored in the washing tub, and the drive unit is operated to rotate the inner tub, thereby causing the water in the washing tub to rise between the outer tub and the inner tub and be sprayed onto the laundry in the inner tub from the inlet and outlet, and the control unit closes the overflow channel by the stop valve while the inner tub is rotating in the tub rotation process.

[0007] The present invention is also characterized in that the vertical washing machine includes a water supply unit which supplies water into the washing tub, and the control unit executes a water supply process in which, before the tub rotation process, the drainage path is closed by the drain valve and the water supply unit stores water in the washing tub, and during the water supply process, the overflow path is kept open by the stop valve.

[0008] The present invention is also characterized in that, during the tank rotation process, the control unit opens the overflow channel using the stop valve in response to the stop of the drive unit.

[0009] In addition, the present invention is characterized in that the top-loading washing machine includes an actuator that operates both the drain valve and the stop valve under the control of the control unit. Effect of the Invention

[0010] According to the present invention, in the vertical washing machine, the tub rotation process is performed in at least one of the washing process and the rinsing process. In the tub rotation process, when water is stored in the washing tub, the inner tub rotates by receiving the torque of the drive unit, so that the water in the washing tub rises between the outer tub and the inner tub and is sprayed on the laundry in the inner tub from the inlet and outlet of the inner tub. By spraying water from above, the laundry on the inlet and outlet side can also be washed. During the rotation of the inner tub in the tub rotation process, the overflow channel connected to the overflow port of the outer tub is closed by the water stop valve, so that water can be saved by eliminating the waste of water in the washing tub being discharged from the discharge channel through the overflow channel. Furthermore, in this case, in each of the washing process and the rinsing process, the tub rotation process can be performed not only in the latter half of the process in which the water level in the washing tub drops depending on washing and rinsing, but also in the first half of the process in which the water level in the washing tub is high. If the tub rotation process is performed in the first half of the process, the amount of water sprayed on the laundry in the inner tub can be increased, thereby improving the washing performance.

[0011] In addition, according to the present invention, during the water supply process before the tub rotation process, the overflow channel is opened by the water stop valve, so that the water that reaches the overflow outlet can be guided from the overflow channel to the drain and discharged. In other words, in a vertical washing machine, the overflow function can be enabled during the water supply process, when overflow is required, and the overflow function can be disabled during the rotation of the inner tub during the tub rotation process, when overflow is not required.

[0012] Furthermore, according to the present invention, in the tub rotation process, the overflow channel can be opened to activate the overflow function in response to the stopping of the drive unit, i.e., the stopping of the spraying of water onto the laundry in the inner tub.

[0013] Furthermore, according to the present invention, the water stop valve and the drain valve that opens and closes the drain passage can be operated by a common actuator. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic vertical cross-sectional view of a top-loading washing machine according to an embodiment of the present invention; [Diagram 2]FIG. 2 is a block diagram showing the electrical configuration of the vertical washing machine. [Diagram 3] 4 is a flowchart showing a washing operation performed in the vertical washing machine. [Figure 4] 10 is a flowchart showing a tub rotation process in a washing operation. [Diagram 5] FIG. 2 is a schematic perspective view of an upper portion of a washing tub in a vertical washing machine. [Figure 6] FIG. 11 is a block diagram showing an electrical configuration of a vertical washing machine according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic vertical cross-sectional view of a vertical washing machine 1 according to an embodiment of the present invention. The vertical direction in FIG. 1 is referred to as the vertical direction Z of the vertical washing machine 1, and the upper side of the vertical direction Z is referred to as the upper side Z1 and the lower side is referred to as the lower side Z2. The vertical washing machine 1 includes a housing 2 forming its outer shell, an outer tub 3 arranged in the housing 2, an inner tub 4 arranged in the outer tub 3, a pulsator 5 arranged in the inner tub 4, a motor 6 as an example of a drive unit arranged on the lower side Z2 of the outer tub 3, and an electric clutch 7 that switches the destination of the torque generated by the motor 6. The outer tub 3 and the inner tub 4 are combined to form a washing tub 8.

[0016] The housing 2 is made of metal, for example, and is formed in a box shape. An opening 2B that connects the inside and outside of the housing 2 is formed on a top surface 2A of the housing 2. A door 10 for opening and closing the opening 2B is provided on the top surface 2A. A display operation unit 11 composed of a liquid crystal operation panel or the like is provided around the opening 2B on the top surface 2A. By operating the display operation unit 11, a user of the vertical washing machine 1 can select operating conditions for the washing operation performed by the vertical washing machine 1 and can instruct the vertical washing machine 1 to start or stop the washing operation. Information for the user is displayed on the display operation unit 11.

[0017] The outer tub 3 is made of, for example, resin, and is formed into a cylindrical shape with a bottom. The axis J of the outer tub 3 extends in the vertical direction Z through the center of the outer tub 3. In the following, the radial direction based on the axis J is referred to as the radial direction R, and the circumferential direction around the axis J is referred to as the circumferential direction L. Within the radial direction R, the direction approaching the axis J is referred to as the radial inner direction R1, and the direction away from the axis J is referred to as the radial outer direction R2.

[0018] The outer tank 3 has a substantially cylindrical circumferential wall 3A arranged 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 a ring-shaped annular wall 3C that protrudes radially inward R1 along the upper edge of the circumferential wall 3A. An overflow port 3D that penetrates the circumferential wall 3A in the radial direction R is provided at the upper end of the circumferential wall 3A. An opening 3E that communicates with the hollow portion of the circumferential wall 3A from the upper side Z1 is provided inside the annular wall 3C. The opening 3E faces and communicates with the opening 2B of the housing 2 from the lower side Z2.

[0019] The annular wall 3C is provided with a door 12 for opening and closing the opening 3E. The lower surface of the annular wall 3C is provided with a guide surface 3F that is inclined downward while edging the opening 3E. The bottom wall 3B is formed in a disk shape extending substantially horizontally. An insertion hole 3G is provided at the center of the circle of the bottom wall 3B, and a drainage port 3H is provided in the bottom wall 3B on the radially outer side R2 of the insertion hole 3G. The insertion hole 3G and the drainage port 3H penetrate the bottom wall 3B in the vertical direction Z. In the outer tub 3, the overflow port 3D is positioned higher than the drainage port 3H, and the opening 3E is positioned higher than the overflow port 3D.

[0020] A water supply passage 13 connected to a tap for city water is connected to the annular wall 3C of the outer tub 3 from the upper side Z1. A water supply valve 14 is provided in the middle of the water supply passage 13. The water supply valve 14 is formed, for example, of a solenoid valve. The water supply passage 13 and the water supply valve 14 form a water supply section 15 that supplies water into the washing tub 8. When the water supply valve 14 is opened, it opens the middle of the water supply passage 13, thereby opening the entire water supply passage 13. When the water supply valve 14 is closed, it blocks the water supply passage 13 in the middle by closing the middle of the water supply passage 13. In the initial state immediately after the power of the vertical washing machine 1 is turned on, the water supply valve 14 is in a closed state.

[0021] One end of a drainage channel 16 is connected to a drain outlet 3H in the bottom wall 3B of the outer tank 3. A drain valve 17 is provided in the middle of the drainage channel 16. When the drain valve 17 is opened, it opens a part of the drainage channel 16, thereby opening the entire drainage channel 16. When the drain valve 17 is closed, it blocks the drainage channel 16 partway by closing a part of the drainage channel 16. In the initial state, the drain valve 17 is in a closed state.

[0022] When the water supply valve 14 is opened with the drain valve 17 closed, water is supplied from the water supply passage 13 into the outer tub 3, and water is stored in the outer tub 3, i.e., in the washing tub 8. When the water supply valve 14 is closed, the water supply stops. When the drain valve 17 is opened, the water in the washing tub 8 is discharged outside the machine, i.e., outside the housing 2, through the drain passage 16.

[0023] The inner tub 4 is made of, for example, metal, is formed into a cylindrical shape with a bottom that is one size smaller than the outer tub 3, and can accommodate laundry Q inside. The inner tub 4 is arranged coaxially within the outer tub 3. The inner tub 4 is rotatable about the axis J when housed within the outer tub 3. The inner tub 4 has a substantially cylindrical circumferential wall 4A arranged along the up-down direction Z, a bottom wall 4B that closes the hollow portion of the circumferential wall 4A from the lower side Z2, and a ring-shaped annular wall 4C that protrudes radially inward R1 along the upper edge of the circumferential wall 4A.

[0024] The inner peripheral surface of the circumferential wall 4A is the inner peripheral surface of the inner tub 4. The circumferential wall 4A is surrounded by the circumferential wall 3A of the outer tub 3. The bottom wall 4B is provided at the lower end of the inner tub 4. The annular wall 4C faces the annular wall 3C of the outer tub 3 from the lower side Z2. An entrance / exit 4D is provided inside the annular wall 4C. The entrance / exit 4D is located at the upper end of the inner tub 4 and exposes the hollow part of the circumferential wall 4A to the upper side Z1. The entrance / exit 4D faces the opening 3E of the outer tub 3 from the lower side Z2 and communicates with it. A user puts laundry Q in and takes it out of the inner tub 4 from the upper side Z1 through the opened opening 2B, opening 3E, and entrance / exit 4D.

[0025] A plurality of through holes 4E are provided in the circumferential wall 4A and the bottom wall 4B of the inner tub 4, and the water in the outer tub 3 flows between the outer tub 3 and the inner tub 4 through the through holes 4E and is also stored in the inner tub 4. Therefore, the water level in the outer tub 3 and the water level in the inner tub 4 are the same. Note that the through holes 4E may not be provided in the circumferential wall 4A and may be provided only in the bottom wall 4B.

[0026] The bottom wall 4B of the inner tank 4 is formed in a disk shape and extends approximately parallel to the bottom wall 3B of the outer tank 3 at a distance to the upper side Z1. An insertion hole 4F penetrating the bottom wall 4B is formed at the circular center position of the bottom wall 4B coinciding with the axis J. A tubular support shaft 18 is provided in the bottom wall 4B, surrounding the insertion hole 4F and extending to the lower side Z2 along the axis J. The support shaft 18 is inserted into the insertion hole 3G of the bottom wall 3B of the outer tank 3, and the lower end of the support shaft 18 is located on the lower side Z2 of the bottom wall 3B.

[0027] The pulsator 5 is formed in a disk shape with the axis J as its center, and is disposed on the bottom wall 4B inside the inner tub 4. The upper surface of the pulsator 5 facing the entrance / exit 4D of the inner tub 4 is provided with a plurality of raised, radially disposed protuberances 5A. The pulsator 5 is provided with a rotating shaft 19 extending from its center along the axis J to the lower side Z2. The rotating shaft 19 is inserted into the hollow portion of the support shaft 18, and the lower end of the rotating shaft 19 is located on the lower side Z2 than the bottom wall 3B of the outer tub 3.

[0028] The motor 6 is an electric motor such as an inverter motor. The motor 6 is disposed below the outer tub 3 on the lower side Z2 inside the housing 2. The motor 6 has an output shaft 20 that rotates about an axis J, and outputs generated torque from the output shaft 20.

[0029] The clutch 7 is interposed between the lower ends of the support shaft 18 and the rotating shaft 19 and the upper end of the output shaft 20 protruding from the motor 6 to the upper side Z1. A known transmission mechanism is used as the clutch 7. The clutch 7 selectively transmits the torque output from the output shaft 20 of the motor 6 to one or both of the support shaft 18 and the rotating shaft 19. When the torque from the motor 6 is transmitted to the support shaft 18, the inner tub 4 receives the torque of the motor 6 and rotates around the axis J. When the torque from the motor 6 is transmitted to the rotating shaft 19, the pulsator 5 receives the torque of the motor 6 and rotates around the axis J.

[0030] The vertical washing machine 1 further includes an overflow channel 21 having one end 21A connected to the overflow port 3D of the circumferential wall 3A and the other end 21B connected to a downstream portion of the drain channel 16 that is farther from the drain port 3H than the drain valve 17. The other end 21B is located at a lower position than the one end 21A. When the water level in the washing tub 8 rises to the overflow port 3D, the water on the water surface side, i.e., the upper side Z1, in the washing tub 8 falls through the overflow channel 21 from the overflow port 3D and is guided to the drain channel 16, through which it is discharged to the outside of the machine.

[0031] The vertical washing machine 1 also includes a stop valve 22 provided in the overflow channel 21. When the stop valve 22 is opened, it opens the overflow channel 21 in its entirety by opening the overflow channel 21 in its entirety. When the stop valve 22 is closed, it blocks the overflow channel 21 in its entirety by closing the overflow channel 21 in its entirety. In the initial state, the stop valve 22 is in an open state.

[0032] 2 is a block diagram showing the electrical configuration of the vertical washing machine 1. The vertical washing machine 1 includes a microcomputer 25 as an example of a control unit. The microcomputer 25 includes, for example, a CPU 26, a memory 27 such as a ROM or a RAM, and a timer 28 for measuring time, and is built into the housing 2 (see FIG. 1).

[0033] The motor 6, clutch 7, water supply valve 14, drain valve 17, and stop valve 22 are each electrically connected to the microcomputer 25 via, for example, a drive circuit 29, and the display operation unit 11 is also electrically connected to the microcomputer 25. The microcomputer 25 turns the motor 6 ON to operate it and turns it OFF to stop it. The microcomputer 25 can also control the rotation direction of the motor 6. Therefore, the motor 6 can rotate forward and backward. The microcomputer 25 controls the clutch 7 to switch the transmission destination of the torque of the motor 6 to one or both of the inner tub 4 and the pulsator 5.

[0034] The microcomputer 25 controls the opening and closing of the water supply valve 14, the drain valve 17, and the stop valve 22. Specifically, the vertical washing machine 1 includes a torque motor 30 that operates the drain valve 17, and an actuator 31 that is provided separately from the torque motor 30 and operates the stop valve 22, and the torque motor 30 and the actuator 31 are connected to a drive circuit 29. Therefore, the microcomputer 25 controls the opening and closing of the drain valve 17 by controlling the operation of the torque motor 30, and controls the opening and closing of the stop valve 22 by controlling the operation of the actuator 31.

[0035] When the user operates the display operation unit 11 to select operating conditions and the like, the selection is accepted by the microcomputer 25. The microcomputer 25 controls the display contents of the display operation unit 11.

[0036] The vertical washing machine 1 further includes a buzzer 32, a rotation speed reading device 33, and a water level detection unit 34, which are electrically connected to the microcomputer 25. The microcomputer 25 notifies the user of the start and end of a washing operation by making the buzzer 32 generate a predetermined sound.

[0037] The rotation speed reading device 33 is a device that reads the rotation speed of the motor 6, more precisely, the rotation speed of the output shaft 20 of the motor 6, and is composed of, for example, a Hall IC. The rotation speed read by the rotation speed reading device 33 is input to the microcomputer 25 in real time. The microcomputer 25 controls the motor 6 so that it rotates at a desired rotation speed by controlling the duty ratio of the voltage applied to the motor 6 based on the input rotation speed. Note that the rotation speeds 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 the reduction ratio of the clutch 7.

[0038] The water level detection unit 34 is a water level sensor that detects the water level in the washing tub 8. As an example of the water level detection unit 34, a pressure type water level sensor that detects the water level in the washing tub 8 based on the pressure in the outer tub 3 can be used.

[0039] The microcomputer 25 executes a washing operation by controlling the operation of the motor 6, the clutch 7, the water supply valve 14, the drain valve 17, and the water stop valve 22. The washing operation includes a washing process for washing the laundry Q, a rinsing process for rinsing the laundry Q after the washing process, and a spin-drying process for spin-drying the laundry Q by rotating the inner tub 4 after the rinsing process. The vertical washing machine 1 may be a washer-dryer that also executes a drying process for drying the laundry Q after the spin-drying process. In this embodiment, the rinsing process is executed twice, the first rinsing process being referred to as the first rinsing process, and the second rinsing process being referred to as the second rinsing process. The rinsing process may be executed only once, instead of multiple times.

[0040] When the user puts laundry Q into the inner tub 4 and issues an instruction to start the washing operation, the microcomputer 25 starts the washing operation. The user may put detergent into the inner tub 4 before or after putting in the laundry Q. Referring to the flowchart of FIG. 3, first, the microcomputer 25 detects the amount of laundry Q in the inner tub 4, that is, the load amount (step S1). As an example of load amount detection, the microcomputer 25 detects the load amount from the variation in the number of rotations of the motor 6 when the inner tub 4 is rotated steadily at a low speed. The microcomputer 25 determines the water level W (see FIG. 1) of the water to be supplied and stored in the inner tub 4 based on the load amount detected earlier. The relationship between the water level W and the load amount is obtained in advance by experiments or the like and stored in the memory 27.

[0041] Then, as a water supply process at the beginning of the washing process, microcomputer 25 closes drain valve 17 to close drain passage 16, and continuously opens water supply valve 14 to supply water into washing tub 8 (step S2). This causes water to accumulate in washing tub 8 and the water level to rise. When the water level in washing tub 8 rises to the previously determined water level W, microcomputer 25 closes water supply valve 14 to stop water supply. This ends the water supply process. During the water supply process, microcomputer 25 opens stop valve 22 to keep overflow passage 21 open.

[0042] Next, in a state where water is stored in the washing tub 8, the microcomputer 25 executes the stirring process (step S3). Specifically, the microcomputer 25 switches the clutch 7 as necessary so that the torque of the motor 6 is transmitted to the pulsator 5, and then drives the motor 6 to rotate the pulsator 5. The pulsator 5 may rotate continuously in the same direction, but in this embodiment, the pulsator 5 is reversed so that the normal and reverse rotations are alternately repeated at intervals of 1 to 2 seconds by intermittent driving of the motor 6. In the stirring process, the laundry Q in the inner tub 4 is stirred and washed by the reversing pulsator 5. The pulsator 5 may rotate even during the water supply process in step S2, which makes it easier for the detergent to dissolve in water. Dirt on the laundry Q is broken down by the detergent dissolved in water. When a predetermined stirring time has elapsed, the microcomputer 25 ends the stirring process.

[0043] After the stirring process, the microcomputer 25 executes the loosening process while water continues to accumulate in the inner tub 4 (step S4). In the loosening process, the microcomputer 25 reverses the pulsator 5 by intermittently driving the motor 6 under conditions different from those in the stirring process. In this embodiment, as an example, the pulsator 5 reverses at a higher rotation speed than in the stirring process so as to alternately rotate forward and backward at intervals of 0.5 seconds, which is shorter than that in the stirring process. As a result, the laundry Q immersed in water in the inner tub 4 is loosened by the reversing pulsator 5. Therefore, the uneven distribution of the laundry Q is eliminated. The uneven distribution of the laundry Q refers to the uneven distribution of the laundry Q in the inner tub 4, and is also called imbalance. When a predetermined loosening time has elapsed, the microcomputer 25 ends the loosening process. In the washing process, the water level W immediately after the water supply process gradually decreases according to the progress of each process in the washing process, such as the stirring process and the loosening process.

[0044] After the loosening process, the microcomputer 25 executes the tub rotation process (step S5). Specifically, referring to the flowchart of Fig. 4, the microcomputer 25 first switches the clutch 7 so that the torque of the motor 6 is transmitted to the inner tub 4 (step S51). Next, the microcomputer 25 closes the overflow passage 21 by closing the stop valve 22 (step S52).

[0045] Next, microcomputer 25 checks whether the water level in washing tub 8 has reached a predetermined tub rotation water level (step S53). The tub rotation water level is a water level at which the water in outer tub 3 will not overflow from opening 3E when inner tub 4 rotates from now on, and is specifically higher than half the internal height of inner tub 4. If the water level in inner tub 4 is not at the tub rotation water level (NO in step S53), the water level in inner tub 4 is higher than the tub rotation water level, so microcomputer 25 opens drain valve 17 to drain washing tub 8 (step S54).

[0046] If the water level in the washing tub 8 has reached the tub rotation water level (YES in step S53), the microcomputer 25 closes the drain valve 17 to close the drain passage 16, and operates the motor 6 in a state where water is stored in the washing tub 8 up to the tub rotation water level (step S55). This causes the inner tub 4 to rotate at high speed, for example at 200 rpm. Then, a vortex is generated in the outer tub 3, and the water surface, which was previously horizontal, curves in a U-shape so that the center on the axis J side becomes lower and the outer periphery on the radially outer side R2 becomes higher (see the two-dot chain line S in FIG. 1). This causes the water in the washing tub 8 to rise between the circumferential wall 3A of the outer tub 3 and the circumferential wall 4A of the inner tub 4.

[0047] The rising water passes between the ribs 3I arranged in a line on the underside of the annular wall 3C of the outer tub 3, swirling in a spiral and falls, and is sprayed onto the laundry Q in the inner tub 4 through the entrance 4D of the inner tub 4 (see the thick two-dot chain lines in Figs. 1 and 5). The guide surface 3F of the annular wall 3C of the outer tub 3 guides the water passing between the ribs 3I downward toward the entrance 4D (see Fig. 1).

[0048] Even if the amount of laundry Q is so large that it is about to spill out of the water surface after the water supply process, the laundry Q on the entrance / exit 4D side can be reliably washed by spraying water from the upper side Z1 due to the rotation of the inner tub 4. Furthermore, washing by spraying water can reduce damage to the laundry Q. Note that the tub rotation process may be performed only in the case of large-volume washing where the amount of laundry Q is equal to or greater than a predetermined amount.

[0049] Since the tub rotation process is started with the laundry Q having been preliminarily eliminated by the loosening process in step S4, the rotation speed of the inner tub 4 increases smoothly to the rotation speed at which watering starts during the tub rotation process. This allows the tub rotation process to be carried out smoothly. In addition, since the preliminarily loosening process makes it difficult for abnormal vibrations of the inner tub 4 to occur during the tub rotation process, it is possible to avoid the need to stop the rotation of the inner tub 4 in response to abnormal vibrations and eliminate the unevenness of the laundry Q in the inner tub 4. This allows the washing time to be shortened.

[0050] During the tub rotation process, the microcomputer 25 detects the degree of imbalance of the laundry Q in the inner tub 4, that is, the eccentric load, while water continues to accumulate in the inner tub 4 (step S56). Specifically, as the imbalance of the laundry Q increases, the variation in the rotation speed of the motor 6 increases. Therefore, the microcomputer 25 detects the imbalance of the laundry Q in the inner tub 4 by reading the variation in the rotation speed of the motor 6 with the rotation speed reading device 33. In this case, the time required to detect the degree of imbalance of the laundry Q can be reduced compared to the case where the inner tub 4 is drained once and then the degree of imbalance of the laundry Q is detected. The degree of imbalance of the laundry Q may be detected by another known method. If the imbalance of the laundry Q is greater than a predetermined value, the smooth rotation of the inner tub 4 may be affected.

[0051] If no deviation of a predetermined magnitude or more is detected (NO in step S56), and a predetermined tub rotation time has elapsed since the motor 6 started to rotate in step S55 (YES in step S57), the microcomputer 25 stops the motor 6 (step S58). Then, in response to the stopping of the motor 6, the microcomputer 25 opens the stop valve 22 to open the overflow passage 21 (step S59). This ends the tub rotation process.

[0052] As described above, the microcomputer 25 closes the overflow channel 21 by closing the stop valve 22 during steps S52 to S59 in the tub rotation process, that is, while the inner tub 4 is rotating. This prevents the water in the washing tub 8 from being wasted by passing through the overflow channel 21 and being discharged from the drainage channel 16, thereby saving water. Furthermore, in this case, the tub rotation process can be performed not only in the latter half of the washing process when the water level in the washing tub 8 is low due to washing in the agitation process (step S3), but also in the former half of the washing process when the water level in the washing tub 8 is high, for example, immediately after the water supply process (step S2). If the tub rotation process is performed in the former half of the washing process, the amount of water sprayed on the laundry Q in the inner tub 4 can be increased, thereby improving the washing performance, or more precisely, the washing performance. In order to further reduce the discharge of water from inside the washing tub 8 to the overflow channel 21 while the inner tub 4 is rotating, the stop valve 22 may be disposed in the overflow channel 21 near the overflow outlet 3D, or even at the overflow outlet 3D (see FIG. 1).

[0053] On the other hand, during the water supply process before the tub rotation process (step S2), as described above, the microcomputer 25 opens the stop valve 22 to open the overflow channel 21. As a result, when the water level in the washing tub 8 rises during the water supply process and reaches the overflow outlet 3D, the water that has reached the overflow outlet 3D can be guided from the overflow channel 21 to the drainage channel 16 and discharged. In other words, in the vertical washing machine 1, the overflow function can be enabled during the water supply process, when overflow is required, and disabled during the rotation of the inner tub 4 in the tub rotation process, when overflow is not required.

[0054] Then, in the tub rotation process, as described above, the microcomputer 25 opens the stop valve 22 in response to the stop of the motor 6, thereby opening the overflow channel 21 (step S59). In this manner, in the tub rotation process, the overflow channel 21 can be opened in response to the stop of the motor 6, i.e., the stop of the water spraying on the laundry Q, to enable the overflow function. As a modified example, the overflow channel 21 may be always closed during the entire period of the tub rotation process.

[0055] When the microcomputer 25 detects a bias of a predetermined magnitude or more during the tank rotation process (YES in step S56), it checks whether the current bias detection is the first bias detection in the current tank rotation process (step S60). The number of bias detections in the current tank rotation process is temporarily stored in the memory 27.

[0056] If this is the first time that imbalance is detected (YES in step S60), the microcomputer 25 stops the motor 6 to temporarily suspend the rotation of the inner tub 4 (step S61). Then, the microcomputer 25 switches the clutch 7 so that the torque of the motor 6 is transmitted to the pulsator 5, and then reverses the pulsator 5 under the same conditions as the loosening process in step S4, for example, to loosen the laundry Q in the inner tub 4 (step S62). At this time, water has already accumulated in the inner tub 4 and the laundry Q is immersed in the water and in a state where it is easy to loosen, so there is no need to supply water to loosen the laundry Q.

[0057] In order to loosen the laundry Q, the microcomputer 25 may rotate the inner tub 4 instead of the pulsator 5, or may rotate both the inner tub 4 and the pulsator 5. Moreover, the inner tub 4 and the pulsator 5 may rotate in the same direction only, or may rotate in the opposite direction as described above.

[0058] After loosening the laundry Q for a predetermined time, the microcomputer 25 switches the clutch 7 so that the torque of the motor 6 is transmitted to the inner tub 4, and then resumes the rotation of the inner tub 4 (step S55). That is, if the unevenness is detected for the first time in the tub rotation process, the unevenness is eliminated by loosening, and the rotation of the inner tub 4 is resumed. This allows the tub rotation process to be continued without having to stop the tub rotation process once to eliminate the unevenness of the laundry Q and then restart the tub rotation process, thereby further shortening the washing time. On the other hand, if the unevenness is detected for the second or more times in the current tub rotation process (NO in step S60), the microcomputer 25 stops the motor 6 (step S58), opens the water stop valve 22 (step S59), and stops the tub rotation process. Note that the processes related to unevenness detection (steps S56 and S60 to S62) may be omitted in the tub rotation process.

[0059] 3, when the tub rotation process is completed or stopped as described above, the microcomputer 25 executes an agitation process similar to step S3 (step S6). When the agitation process is completed, the washing step is completed.

[0060] Next, the microcomputer 25 rotates the inner tub 4 at high speed with the drain valve 17 open as a spin-drying step after the washing step, i.e., an intermediate spin-drying step (step S7). The laundry in the inner tub 4 is spin-dried by centrifugal force generated by this high-speed rotation. Water that seeps out of the laundry during spin-drying is discharged outside the machine through the drain passage 16. At the end of the intermediate spin-drying step, the microcomputer 25 switches the clutch 7 to stop the motor 6 so that the torque of the motor 6 is not transmitted to the inner tub 4, and the inner tub 4 rotates by inertia. At the end of the intermediate spin-drying step, the microcomputer 25 closes the drain valve 17.

[0061] Next, the microcomputer 25 executes shower rinsing as the first rinsing step (step S8). Specifically, the microcomputer 25 supplies shower water into the inner tub 4 by intermittently opening the water supply valve 14 with the drain valve 17 closed. In this state, the microcomputer 25 rotates the inner tub 4 at a low speed, for example, 30 rpm, so that the shower water reaches every corner of the laundry Q. This allows the laundry Q in the inner tub 4 to be rinsed evenly. Thereafter, the microcomputer 25 executes the same intermediate spin-drying step as step S7 (step S9). Note that each intermediate spin-drying step may be regarded as a part of the processing in the immediately following rinsing step.

[0062] Next, the microcomputer 25 executes a second rinsing step. The content of the second rinsing step is the same as the washing step, except that no detergent is present. Specifically, the microcomputer 25 supplies water as in step S2 (step S10), then agitates and rinses the laundry Q as in step S3 (step S11), loosens the laundry Q as in step S4 (step S12), and executes a tub rotation process as in step S5 (step S13). Then, when the microcomputer 25 agitates and rinses the laundry Q as in step S11 (step S14), the second rinsing step is completed.

[0063] The effect obtained by the tub rotation process in the washing step can also be obtained by the tub rotation process in the second rinsing step. Therefore, for example, even in the first half of the second rinsing step when the water level in the washing tub 8 is high, for example, immediately after the water supply process (step S10), the tub rotation process (step S13) can be executed by closing the water stop valve 22, so that the tub rotation process can be executed in the first half of the second rinsing step. This increases the amount of water sprayed on the laundry Q in the inner tub 4, thereby improving the washing performance, or more precisely, the rinsing performance.

[0064] Finally, the microcomputer 25 executes a final spin-drying step similar to the intermediate spin-drying step (step S15). However, the rotation conditions of the inner tub 4 may be different between the intermediate spin-drying step and the final spin-drying step, and in particular, the maximum rotation speed of the inner tub 4 in the final spin-drying step is higher than the maximum rotation speed of the inner tub 4 in the intermediate spin-drying step. The washing operation ends when the final spin-drying step is completed.

[0065] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the claims.

[0066] For example, in the embodiment described above, each of the stirring process, loosening process, and tub rotation process is performed in both the washing process and the second rinsing process, but it may be performed in only one of the washing process and the second rinsing process, or it may be performed in the first rinsing process. The tub rotation process in the washing process (step S5) and the tub rotation process in the second rinsing process (step S13) may be the same or different as described above. Also, one or both of the stirring process and loosening process may be omitted in the washing operation.

[0067] Fig. 6 is a block diagram showing the electrical configuration of a vertical washing machine 1 according to a modified example. In Fig. 6, the same parts as those explained so far are given the same reference numerals, and explanations of those parts are omitted. The torque motor 30 (see Fig. 2) that operates the drain valve 17 and the actuator 31 (see Fig. 2) that operates the stop valve 22 may be omitted, and the vertical washing machine 1 may include one actuator 41 that operates both the drain valve 17 and the stop valve 22.

[0068] The actuator 41 is composed of a two-stage torque motor or the like, and operates both the drain valve 17 and the stop valve 22 under the control of the microcomputer 25. Specifically, the actuator 41 operates in two stages from the OFF state, so that it can open and close both the drain valve 17 and the stop valve 22 collectively, or selectively open and close only one of the drain valve 17 and the stop valve 22. In this way, the drain valve 17 and the stop valve 22 can be operated by the common actuator 41.

[0069] As another modification, the vertical washing machine 1 may include a three-way valve 42 that serves as both the drain valve 17 and the stop valve 22 (see FIG. 1). In this case, the three-way valve 42 is formed of, for example, a solenoid valve. The three-way valve 42 is disposed at a connection portion of the drain passage 16 to which the other end 21B of the overflow passage 21 is connected. The three-way valve 42 may allow drainage from the overflow passage 21 to the outside of the machine while stopping drainage from the drain outlet 3H, allow drainage from the overflow passage 21 to the outside of the machine while stopping drainage from the overflow passage 21, or stop or allow drainage from either the drain outlet 3H or the overflow passage 21 at the same time.

[0070] In the above-described embodiment, the axis J of the inner tub 4 in the vertical washing machine 1 is arranged to extend vertically along the vertical direction Z (see FIG. 1), but the vertical washing machine 1 also includes a configuration in which the axis J is arranged to be slightly inclined with respect to the vertical direction Z. [Explanation of symbols]

[0071] 1. Top-loading washing machine 3 Outer tank 3D overflow mouth 3E opening 3H Drain port 4 Inner tank 4D entrance / exit 4E Through hole 6 Motor 8 Washing tub 15 Water supply section 16 Drainage Channel 17 Drain valve 21 Overflow channel 22 Water stop valve 25 Microcomputer 41 Actuator Q Laundry Z2 lower side

Claims

1. A drive unit that generates torque; a washing tub having an outer tub provided with a drain outlet, an overflow outlet located at a position higher than the drain outlet, and an opening located at a position higher than the overflow outlet, and for storing water; an inner tub provided with a through hole for passing water between the outer tub and the inner tub, and an inlet / outlet facing the opening from below, and disposed within the outer tub, laundry is put in and taken out through the opening and the inlet / outlet, and the inner tub rotates by receiving a torque from the drive unit; A drainage channel connected to the drain outlet for discharging water from the washing tub; A drain valve that opens and closes the drainage path; An overflow channel connected to the overflow outlet and directing water in the washing tub from the overflow outlet to the drainage channel; A stop valve for opening and closing the overflow channel; A control unit that executes a tub rotation process in which the drainage channel is closed by the drain valve and water is stored in the washing tub, and the drive unit is operated to rotate the inner tub, thereby causing the water in the washing tub to rise between the outer tub and the inner tub and to be showered onto the laundry in the inner tub from the inlet and outlet, during at least one of a washing process and a rinsing process after the washing process, and a control unit that prevents water from flowing from the overflow channel to the drainage channel by closing the overflow channel by the water stop valve during the rotation of the inner tub in the tub rotation process.

2. A water supply unit that supplies water into the washing tub, 2. The vertical washing machine according to claim 1, wherein the control unit executes a water supply process in which the drainage path is closed by the drain valve and the water supply unit is used to store water in the washing tub before the tub rotation process, and during the water supply process, the overflow path is opened by the water stop valve.

3. 3. The vertical washing machine according to claim 1, wherein the control unit opens the overflow channel by using the stop valve in response to the stop of the drive unit during the tub rotation process.

4. The top-loading washing machine according to any one of claims 1 to 3, further comprising an actuator that operates both the drain valve and the water stop valve under the control of the control unit.

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