Washing machine

Abstract

A washing machine capable of accurately determining a rinsing condition of laundry and rinsing the laundry to a clean state. A fully automatic washing machine (1) comprises: a control part (301) for performing a washing operation which comprises a washing cycle in which laundry is washed using detergent-containing water, a rinsing cycle in which the laundry is rinsed using water, and a dehydration cycle in which the laundry is dehydrated using a centrifugal force generated by spinning of a washing and dehydration tub; and a conductivity sensor (60) for measuring the conductivity of the water stored at the bottom in an outer tub (20). In the dehydration cycle subsequent to the rinsing cycle, the control part executes a spun-out liquid conductivity measurement process in which the conductivity sensor is used to measure the conductivity of the liquid spun out of laundry and stored in the outer tub, and adjusts the number of the rinsing cycles on the basis of the conductivity of the spun-out liquid.

Description

washing machine Technical Field

[0001] The present invention relates to a washing machine. Background Art

[0002] Washing machines are known that detect the conductivity of rinsing water (hereinafter referred to as "rinsing water") stored in an outer tub to confirm the rinsing status of the laundry and adjust the number of rinse cycles to prevent under-rinsing. An example of such a washing machine is shown in Patent Document 1 below.

[0003] In the washing machine disclosed in Patent Document 1, during the rinsing cycle, a prescribed amount of rinsing water is supplied to the water receiving tub (outer tub). The wash-and-spin tub rotates, and the rinsing water in the water receiving tub is pumped through a circulating water circuit to the upper portion of the wash-and-spin tub, where it is sprayed from a water supply nozzle into the interior of the wash-and-spin tub. A conductivity sensing unit midway through the circulating water circuit senses the conductivity of the rinsing water. If the conductivity is greater than a prescribed value, the rinsing cycle is repeated via an intermediate spin cycle if the number of repetitions has not reached the prescribed number. If the number of repetitions reaches the prescribed number, the rinsing cycle of water storage rinsing is performed. During the water storage rinsing cycle, water is supplied to a prescribed level in the wash-and-spin tub, i.e., the water receiving tub, and a stirring blade disposed within the wash-and-spin tub rotates, stirring the laundry.

[0004] In a configuration that senses the conductivity of the rinsing water stored in the outer drum, as in conventional washing machines, if the laundry cannot be properly rinsed and the detergent cannot be smoothly discharged from the laundry into the rinsing water, the sensed conductivity of the rinsing water will become smaller. Therefore, there is a possibility that the laundry may be judged to be sufficiently rinsed even though a lot of detergent remains in the laundry, and the washing operation may be terminated in an insufficiently rinsed state.

[0005] It should be noted that in the washing machine of Patent Document 1, for example, if the force of the water sprayed onto the laundry decreases depending on the arrangement of the laundry in the washing and dehydration tub, it is considered difficult for the detergent to be smoothly discharged from the laundry into the rinse water.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 7-308485

[0009] Summary of the Invention

[0010] Problems to be solved by the invention

[0011] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a washing machine that can accurately determine the rinsing status of laundry and can process the laundry into a rinsed and clean state.

[0012] Solutions for solving problems

[0013] The main embodiment of the present invention relates to a washing machine comprising: an outer tub disposed within a housing and storing water; a washing unit including an inner tub disposed within the outer tub and a drive motor, wherein the drive motor applies a mechanical force to laundry contained within the inner tub based on torque generated by the drive motor; a control unit controlling the operation of the washing unit to execute a washing operation, wherein the washing operation includes a washing process in which the laundry is washed with water containing detergent, a rinsing process in which the laundry is rinsed with water, and a dehydration process in which the laundry is dehydrated by centrifugal force generated by the rotation of the inner tub; and a conductivity sensor for measuring the conductivity of the water stored at the bottom of the outer tub. The control unit, during the dehydration process subsequent to the rinsing process, performs a dehydration conductivity measurement process in which the conductivity sensor measures the conductivity of dehydrated liquid squeezed from the laundry and stored in the outer tub, and adjusts the number of rinsing processes based on the dehydration conductivity.

[0014] For example, when the conductivity of the deliquescence is measured during the subsequent dehydration process of the second rinsing process, the control unit can perform the following processing as a method of adjusting the number of rinsing processes: when it is determined that the rinsing is insufficient based on the conductivity of the deliquescence, a rinsing process is added after the dehydration process; when it is determined that the rinsing is sufficient based on the conductivity of the deliquescence, a rinsing process is not added after the dehydration process.

[0015] Alternatively, when the conductivity of the deliquescence is measured during the subsequent dehydration process of the first rinsing process, the control unit can perform the following processing as a method of adjusting the number of rinsing processes: when it is determined based on the conductivity of the deliquescence that rinsing may not be sufficient in the remaining rinsing process, two rinsing processes are performed after the dehydration process; when it is determined based on the conductivity of the deliquescence that rinsing can be sufficient in the remaining rinsing process, one rinsing process is performed after the dehydration process.

[0016] The washing machine of this embodiment directly measures the conductivity of water that may contain detergent from the laundry. Unlike measuring the conductivity of rinsing water stored in the outer tub, the amount of residual detergent in the laundry is reliably reflected in the measured conductivity. This allows for highly accurate assessment of the rinsing status of the laundry, allowing for additional rinsing steps if rinsing is insufficient, ensuring that the laundry is rinsed clean.

[0017] The washing machine of this embodiment may further include a water supply device including a water supply valve connected to a faucet to supply tap water into the outer tub. In this case, the control unit may be configured to execute a water conductivity measurement process in which the water supply device is activated to store tap water in the outer tub, and the conductivity of the tap water is measured by the conductivity sensor. The conductivity of the tap water is determined as a reference conductivity, the dewatering conductivity is corrected such that the greater the reference conductivity, the smaller the dewatering conductivity, and the number of rinse cycles is adjusted based on the corrected dewatering conductivity.

[0018] According to the above configuration, by correcting the conductivity of the drained water using the reference conductivity, the influence of different properties of tap water can be eliminated, thereby accurately determining the amount of detergent remaining in the laundry.

[0019] As described above, when a configuration is employed in which a reference conductivity is used to calibrate the conductivity of the liquid removed, a configuration may be employed in which a detergent dispenser is further provided, the detergent dispenser including a detergent box storing liquid detergent and automatically dispensing the detergent from the detergent box into the outer tub. In this case, the control unit may be configured to operate the detergent dispenser and the water supply device during water supply during the washing process to store water containing detergent in the outer tub, and to perform the water conductivity measurement process before the detergent dispenser dispenses detergent into the outer tub.

[0020] According to the above configuration, the detergent dispensed by the detergent dispenser can be prevented from mixing with the tap water measured during the water conductivity measurement process, and the conductivity of the tap water with a high detergent concentration can be prevented from being set as the reference conductivity.

[0021] As described above, when a configuration is employed in which the conductivity of the deliquescence is corrected using a reference conductivity, a configuration further comprising a storage unit may be employed. In this case, the control unit may be configured to store the reference conductivity in the storage unit, and when the conductivity of the tap water measured during the water conductivity measurement is lower than the reference conductivity stored in the storage unit, the control unit may determine the conductivity of the tap water as the new reference conductivity.

[0022] According to the above configuration, the lowest conductivity of the tap water measured during the previous water conductivity measurement process is set as the reference conductivity. Therefore, even if the tap water stored in the outer tub may be affected by dirt and detergent in the laundry, the conductivity of the tap water that has approached its original value through repeated washing operations is set as the reference conductivity. This allows for more accurate determination of the amount of detergent remaining in the laundry.

[0023] As described above, in the case of adopting a configuration in which a reference conductivity is used to correct the conductivity of the deliquescence, the control unit may adopt the following configuration: the first water conductivity measurement process is performed before the cleaning process, the second water conductivity measurement process is performed after the dehydration process subsequent to the first rinsing process, the smaller of the two conductivities of the tap water measured in the first water conductivity measurement process and the second water conductivity measurement process is determined as the reference conductivity, and the deliquescence conductivity measurement process is performed in the dehydration process subsequent to the second rinsing process.

[0024] With this configuration, the tap water conductivity measured in the first and second water conductivity measurement processes can be set as the reference conductivity, the one that is less affected by laundry dirt and detergent and closer to its original value. This allows for more accurate determination of the amount of detergent remaining in the laundry.

[0025] As described above, when a configuration is employed in which the conductivity of the drained liquid is corrected using a reference conductivity, the following configuration may be employed: the conductivity sensor includes a pair of electrodes arranged to protrude upward from the inner surface of the bottom portion of the outer tub. In this case, the control unit may be configured to monitor the rate of change in conductivity measured by the conductivity sensor during the water conductivity measurement process and determine the conductivity after the rate of change falls below a predetermined value as the conductivity of the tap water; and to monitor the rate of change in conductivity measured by the conductivity sensor during the drained liquid conductivity measurement process and determine the conductivity after the rate of change falls below the predetermined value as the conductivity of the drained liquid.

[0026] According to the above configuration, the conductivity measured when the pair of electrodes are completely submerged is determined as the conductivity of the tap water and the conductivity of the drain liquid, so the conductivity of the tap water itself and the conductivity of the drain liquid itself can be accurately measured.

[0027] In the washing machine of this embodiment, the washing operation may include at least two rinsing cycles, an intermediate spin cycle following the first rinsing cycle, and a final spin cycle following the second rinsing cycle. In the final spin cycle, the inner tub rotates at a higher spin speed for a longer spin time than in the intermediate spin cycles. In this case, the control unit may be configured to perform the dewatered liquid conductivity measurement process during the final spin cycle, and when the rinsing cycle is added based on the dewatered liquid conductivity, the spin speed is changed to a lower value and / or the spin time is shortened during the final spin cycle, and the final spin cycle is performed after the added rinsing cycle.

[0028] According to the above configuration, the time required for the final spin-drying process before the additional rinsing process can be shortened, and an increase in the washing operation time due to the additional rinsing process and the final spin-drying process can be suppressed.

[0029] Effects of the Invention

[0030] According to the present invention, a washing machine can be provided that can determine the rinsing status of laundry with high accuracy and can process the laundry into a rinsed and clean state.

[0031] The effects and significance of the present invention will become more apparent through the description of the following embodiments. However, the following embodiments are merely examples of implementing the present invention, and the present invention is not limited to the contents described in the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1 is a side sectional view of a fully automatic washing machine according to an embodiment.

[0033] FIG2 is a diagram schematically showing the configuration of the water supply device according to the embodiment.

[0034] Fig. 3(a) is a top cross-sectional view of the outer tub according to the embodiment. Fig. 3(b) is a side cross-sectional view of the periphery of the conductivity sensor in the outer tub, taken along line AA' of Fig. 3(a) according to the embodiment.

[0035] FIG4 is a block diagram showing the configuration of the fully automatic washing machine according to the embodiment.

[0036] FIG5 is a flowchart illustrating a control process performed by a control unit during the washing operation according to the embodiment.

[0037] FIG6 is a flowchart illustrating a control process performed by the control unit during the water conductivity measurement process included in the washing operation according to the embodiment.

[0038] FIG. 7 is a flowchart illustrating a control process performed by the control unit during the measurement of the deliquescence conductivity included in the washing operation according to the embodiment.

[0039] FIG. 8 is a flowchart illustrating a control process performed by the control unit during the washing operation according to Modification 1. FIG.

[0040] FIG. 9 is a flowchart illustrating a control process performed by the control unit during the rinse addition determination process included in the washing operation according to Modification 1. FIG.

[0041] FIG. 10 is a flowchart showing a control process performed by the control unit during the washing operation according to Modification 2. FIG.

[0042] Explanation of the accompanying symbols 1: fully automatic washing machine (washing machine); 10: housing; 20: outer barrel; 22: washing and dehydration barrel (inner barrel); 31: driving motor; 60: conductivity sensor; 62: electrode; 100: water supply device; 100a: detergent feeding device; 111: first water supply valve (water supply valve); 112: second water supply valve (water supply valve); 170: detergent box; 202: bottom portion; 301: control unit; 302: storage unit; WU: washing unit. DETAILED DESCRIPTION

[0043] Hereinafter, a fully automatic washing machine 1 as one embodiment of the washing machine of the present invention will be described with reference to the drawings.

[0044] FIG1 is a side sectional view of a fully automatic washing machine 1 .

[0045] The fully automatic washing machine 1 includes a housing 10 forming an outer shell. Housing 10 comprises a rectangular cylindrical body 11 with open top and bottom surfaces, an upper panel 12 covering the upper surface of body 11, and a footrest 13 supporting body 11. A laundry inlet 14 is formed on upper panel 12. Inlet 14 is covered by a freely openable and closable upper cover 15. A control unit 16 is disposed within the front portion of upper panel 12. Control unit 16 controls the washing operation performed by the fully automatic washing machine 1.

[0046] An outer tub 20 with an open top is disposed within the housing 10. The outer tub 20 is elastically suspended by four suspension rods 21 having vibration isolation mechanisms. The outer tub 20 has a substantially cylindrical peripheral surface 201 and a substantially disc-shaped bottom surface 202.

[0047] A washing and dehydrating bucket 22 is disposed within the outer tub 20. The washing and dehydrating bucket 22 is cylindrical in shape with a bottom, is open upward, and rotates around a rotation axis extending in a vertical direction. Numerous dehydration holes 22a are formed throughout the inner circumference of the washing and dehydrating bucket 22. Numerous discharge holes 22b are also formed on the inner bottom surface of the washing and dehydrating bucket 22.

[0048] A balance ring 23 is provided on the upper portion of the washing and dehydrating barrel 22. In addition, a pulsator 24 is provided at the bottom of the washing and dehydrating barrel 22. A plurality of blades 24a are radially provided on the surface of the pulsator 24. The washing and dehydrating barrel 22 is equivalent to the "inner barrel" of the present invention.

[0049] A drive unit 30 is located on the outside of the bottom portion 202 of the outer tub 20, generating torque to drive the washing / spinning tub 22 and the pulsator 24. The drive unit 30 includes a drive motor 31 and a transmission mechanism 32. The transmission mechanism 32 includes a clutch mechanism 32a. By switching the clutch mechanism 32a, the torque of the drive motor 31 is transmitted only to the pulsator 24 during the washing and rinsing cycles, causing only the pulsator 24 to rotate. During the spin cycle, the torque of the drive motor 31 is transmitted to the pulsator 24 and the washing / spinning tub 22, causing the pulsator 24 and the washing / spinning tub 22 to rotate integrally.

[0050] The washing unit WU is composed of the washing and dehydrating tub 22, the pulsator 24 and the driving unit 30. In the washing unit WU, the driving motor 31 rotates the pulsator 24 and generates a water flow in the washing and dehydrating tub 22, thereby applying a mechanical force to the laundry contained in the washing and dehydrating tub 22 based on the torque generated by the driving motor 31.

[0051] A drain opening 203 is formed on the bottom portion 202 of the outer tub 20. A drain valve 40 is provided at the drain opening 203. The drain valve 40 includes, for example, a valve and a torque motor for opening and closing the valve. A drain hose 41 is connected to the drain valve 40. When the drain valve 40 is opened, water stored in the washing and dehydrating tub 22 and the outer tub 20 is discharged outside the machine through the drain hose 41.

[0052] The outer tub 20 is provided with a water level detector 50 for detecting the water level within the outer tub 20. The water level detector 50 includes an air trap 51 formed at the bottom of the outer tub 20 and a water level sensor 53 connected to the air trap 51 via a hose 52. The water level sensor 53 is a diaphragm-type water level sensor that detects the water level within the outer tub 20 by detecting the air pressure within the air trap 51, which changes according to the water level within the outer tub 20.

[0053] A water supply device 100 is located behind the upper panel 12. The water supply device 100 is connected to a faucet and supplies water to the washing and dehydrating tub 22, i.e., the outer tub 20. Tap water is supplied from the water supply device 100 to the outer tub 20. Furthermore, the water supply device 100 also automatically dispenses liquid detergent into the washing and dehydrating tub 22, i.e., the outer tub 20.

[0054] FIG. 2 is a diagram schematically showing the configuration of the water supply device 100 .

[0055] The water supply device 100 includes a water supply valve unit 110 , a water inlet 120 , a first water supply path 130 , a second water supply path 140 , a three-way valve 150 , a pump 160 , and a detergent box 170 .

[0056] The water supply valve unit 110 is a so-called double valve, comprising a first water supply valve 111 and a second water supply valve 112. The water inlet 113 of the water supply valve unit 110 is connected to a faucet via a water supply hose (not shown). The rated flow rate of the first water supply valve 111 is greater than the rated flow rate of the second water supply valve 112. The first water supply valve 111 and the second water supply valve 112 constitute the "water supply valves" of the present invention.

[0057] The water injection port portion 120 is formed into a box shape, is positioned at the top of the rear portion of the washing and dehydration bucket 22. The bottom surface of the water injection port portion 120 is formed with a water injection port 121 that opens downward. As shown in Figure 1, the water injection port 121 is positioned at the top of the rear end portion of the washing and dehydration bucket 22, facing in the washing and dehydration bucket 22.

[0058] The first water supply passage 130 and the second water supply passage 140 are disposed between the water supply valve unit 110 and the water inlet 120. The upstream end of the first water supply passage 130 is connected to the first water supply valve 111, and the downstream end of the first water supply passage 130 is connected to the water inlet 120. The upstream end of the second water supply passage 140 is connected to the second water supply valve 112, and the downstream end of the second water supply passage 140 is connected to the water inlet 120.

[0059] The three-way valve 150 is disposed in the second water supply passage 140 . The pump 160 is, for example, a piston pump, and is disposed in the second water supply passage 140 downstream of the three-way valve 150 .

[0060] Liquid detergent is stored in the detergent box 170. An inlet 171 is formed on the upper surface of the detergent box 170. A filter (not shown) is attached to the inlet 171 to capture foreign matter that enters through the inlet 171. A downwardly extending discharge portion 172 is formed on the bottom surface of the detergent box 170. A cylindrical discharge port 173 is formed on the circumference of the discharge portion 172. A supply pipe 180 is connected to the discharge port 173. The detergent box 170 is connected to the three-way valve 150 via the supply pipe 180.

[0061] It should be noted that the second water supply valve 112 , the second water supply path 140 , the three-way valve 150 , the pump 160 , and the detergent box 170 constitute the detergent dispensing device 100 a .

[0062] When water is supplied to the outer tub 20 , the first water supply valve 111 and the second water supply valve 112 are opened. Thus, the water supply device 100 releases water from above the washing and dehydration tub 22 into the washing and dehydration tub 22 .

[0063] During water supply, when detergent dispenser 100a dispenses detergent into the wash / spin drum 22 (i.e., outer tub 20), three-way valve 150 is switched to connect supply pipe 180 to the downstream side of three-way valve 150 in second water supply passage 140. Pump 160 then operates, sucking air upstream of pump 160 from second water supply passage 140, creating a negative pressure upstream. As shown by the dashed line in Figure 2, liquid detergent in detergent box 170 is drawn through supply pipe 180 and delivered to second water supply passage 140. An amount of detergent corresponding to the operating time of pump 160 accumulates in second water supply passage 140.

[0064] Next, three-way valve 150 is switched to connect the upstream and downstream sides of the second water supply passage 140. Second water supply valve 112 is opened, and as shown by the solid arrow in Figure 2, water from the faucet is supplied to the second water supply passage 140. The water flowing through the second water supply passage 140 flushes away the detergent stored in the second water supply passage 140. The washed-away detergent flows along with the water toward the water inlet 120 and is then poured into the washing and dehydration tub 22 through the water inlet 121.

[0065] Fig. 3(a) is a top cross-sectional view of the outer tub 20. Fig. 3(b) is a side cross-sectional view of the outer tub 20 and its surroundings, taken along line AA' of Fig. 3(a).

[0066] The bottom portion 202 of the outer tub 20 is provided with a step 204 extending from the center toward the outer periphery. The inner surface of the bottom portion 202 is inclined so as to become lower as it moves from the right side of the step 204 in the direction of the dashed arrow in Figure 3 . A drain recess 205 is formed to the left of the lowest step 204 on the inner surface of the bottom portion 202, concavely recessing the bottom portion 202. A drain opening 203 is provided within the drain recess 205. Furthermore, the inner surface of the bottom portion 202 of the outer tub 200 slopes downward from the center toward the outer periphery.

[0067] A cylindrical mounting opening 206 is formed on the bottom 202 of the outer tub 20, protruding slightly downward, near the outer periphery and to the left of the drain recess 205, i.e., near the higher side of the inner surface of the bottom 202. An electrode-type conductivity sensor 60 is mounted on the mounting opening 206.

[0068] The conductivity sensor 60 has a cylindrical shape with an upper portion 60a having a smaller outer diameter than the lower portion 60b. The upper portion 60a fits into the mounting opening 206. A gasket 210 is provided between the lower portion 60b and the mounting opening 206 to form a water seal. The top of the upper portion 60a protrudes upward from the inner surface of the bottom portion 202. The upper portion 60a has a groove 61 in its center. The bottom surface of the groove 61 is lower than the inner surface of the bottom portion 202 surrounding the mounting opening 206. The portion of the groove 61 that is lower than the inner surface of the bottom portion 202 forms a residual water pocket 207 that is recessed from the inner surface of the bottom portion 202.

[0069] In the conductivity sensor 60, a pair of electrodes 62 are provided on two opposing sidewall surfaces of the groove portion 61. The pair of electrodes 62 has a square plate shape and is arranged in the space between the bottom portion 202 and the washing and dehydration tub 22 in a manner protruding upward from the bottom surface of the residual water bag 207 which is a part of the inner surface of the bottom portion 202.

[0070] The conductivity sensor 60 measures the conductivity of the tap water supplied from the water supply device 100 to the outer tub 20 and the conductivity of the water squeezed from the laundry during the spin cycle (hereinafter referred to as "spinning liquid"). When a voltage is applied to a pair of electrodes 62 and tap water or spinning liquid accumulates between the electrodes 62, a current corresponding to the conductivity of the tap water or spinning liquid flows between the electrodes 62. The conductivity sensor 60 outputs a signal corresponding to the current value as a conductivity signal representing the conductivity to the control unit 301.

[0071] FIG. 4 is a block diagram showing the configuration of the fully automatic washing machine 1 .

[0072] In addition to the above-mentioned components, the fully automatic washing machine 1 further includes an operation unit 70 and a display unit 80. Furthermore, the control unit 16 includes a control unit 301, a storage unit 302, a motor driver 303, a clutch driver 304, a water supply valve driver 305, a three-way valve driver 306, a drain valve driver 307, and a pump driver 308.

[0073] The operation unit 70 includes various operation buttons such as a power button for turning the power on and off, a start button for starting the washing operation, and a mode selection button for selecting an operation mode, and outputs operation signals corresponding to these operation buttons to the control unit 301.

[0074] The display unit 80 includes a plurality of LEDs and a seven-segment display, and displays the operation mode, the progress of the washing operation and the remaining time, various error indications, and the like under the control of the control unit 301 .

[0075] The water level sensor 53 outputs a water level signal corresponding to the water level in the washing and dehydrating tub 22 , ie, the outer tub 20 , to the control unit 301 .

[0076] The motor drive unit 303 drives the drive motor 31 based on a control signal output from the control unit 301. The motor drive unit 303 includes a rotation sensor that detects the rotational speed of the drive motor 31, an inverter circuit, and other components. The motor drive unit 303 adjusts the drive power so that the drive motor 31 rotates at the rotational speed set by the control unit 301. Furthermore, the motor drive unit 303 includes a current detection circuit that detects the current flowing through the drive motor 31.

[0077] The clutch driving unit 304 drives the clutch mechanism 32 a of the transmission mechanism unit 32 based on a control signal output from the control unit 301 .

[0078] The water supply valve driving unit 305 drives the first water supply valve 111 and the second water supply valve 112 according to a control signal from the control unit 301 .

[0079] The three-way valve driving unit 306 drives the three-way valve 150 based on a control signal from the control unit 301 .

[0080] The drain valve driving unit 307 drives the drain valve 40 based on a control signal from the control unit 301 .

[0081] The pump driving unit 308 drives the pump 160 based on a control signal from the control unit 301 .

[0082] The storage unit 302 includes an EEPROM (Electrically Erasable Programmable Read-Only Memory), a RAM (Random Access Memory), etc. The storage unit 302 stores programs for executing washing operations in various operation modes. In addition, the storage unit 302 stores various operation conditions for the washing operation.

[0083] The control unit 301 includes a CPU (central processing unit), etc., and controls the display unit 80, the motor drive unit 303, the clutch drive unit 304, the water supply valve drive unit 305, the three-way valve drive unit 306, the drain valve drive unit 307 and the pump drive unit 308, etc. based on the signals from the operating unit 70, the water level sensor 53, the conductivity sensor 60, etc., according to the program stored in the storage unit 302.

[0084] The fully automatic washing machine 1 performs washing operations in various operation modes under the control of the control unit 301. The washing operation includes a washing process, a rinsing process, and a spin cycle. The spin cycle includes an intermediate spin cycle performed in the middle of the washing operation and a final spin cycle performed at the end of the washing operation.

[0085] In this embodiment, during the final spin cycle following the rinsing process, a dewatering conductivity measurement process is performed, in which conductivity sensor 60 measures the conductivity of dewatered liquid squeezed from the laundry and stored in outer tub 20. The amount of detergent remaining in the laundry is then determined based on the measured dewatering conductivity. If the dewatering conductivity increases due to a high amount of residual detergent in the laundry, a rinse cycle is added after the final spin cycle.

[0086] The conductivity of the dewatering process varies not only depending on the amount of detergent remaining in the laundry but also on the properties of the water contained in the laundry, namely, the tap water. The properties of tap water vary depending on the region. For example, if the tap water is hard water, containing a large amount of calcium or magnesium ions, the conductivity will be higher than if the tap water is soft water, containing a small amount of calcium or magnesium ions. Therefore, in this embodiment, to eliminate the influence of different tap water properties, a water conductivity measurement process is performed to measure the conductivity of the tap water supplied from the water supply device 100. The conductivity of the tap water is then determined as a reference conductivity, and the determination of whether to add a rinse process is based on the dewatering process conductivity corrected by this reference conductivity.

[0087] Figure 5 is a flowchart illustrating the control process performed by the control unit 301 during the washing operation. Figure 6 is a flowchart illustrating the control process performed by the control unit 301 during the water conductivity measurement process included in the washing operation. Figure 7 is a flowchart illustrating the control process performed by the control unit 301 during the dewatering conductivity measurement process included in the washing operation.

[0088] After the user puts laundry into the washing / dehydrating tub 22, he operates the operating unit 70 to start the washing operation.

[0089] Referring to Figure 5 , when the washing operation begins, the control unit 301 first performs a load sensing process (S101) to detect the load of laundry within the washing and dehydration tub 22. Specifically, the control unit 301 activates the drive motor 31 to rotate the pulsator 24. The load is determined based on the drive current of the drive motor 31 and the amount of inertial rotation until the drive motor 31 stops. A higher load results in a higher drive current and a lower inertial rotation. Based on the detected load, the control unit 301 sets the water supply (washing water level, rinsing water level) for the washing and rinsing processes, as well as the amount of detergent to be added during the washing process. A higher load results in a higher water supply and a higher amount of detergent to be added.

[0090] Next, the control unit 301 executes a first water conductivity measurement process for measuring the conductivity of the tap water supplied from the water supply device 100 ( S102 ).

[0091] 6 , the controller 301 opens the first and second water supply valves 111 and 112, and begins supplying water from the water supply device 100 into the outer tub 20 ( S201 ). Tap water is released from the water inlet 121 of the water supply device 100 into the washing / spinning tub 22. The tap water falls onto the laundry and other items contained within the washing / spinning tub 22, then flows out of the dehydration holes 22a and discharge holes 22b of the washing / spinning tub 22, and accumulates at the bottom of the outer tub 20.

[0092] The control unit 301 measures the conductivity using the conductivity sensor 60 at regular sampling time intervals, for example, 0.1 second intervals, and compares the conductivity measured last time with the conductivity measured this time to monitor whether the rate of change of the conductivity has reached or fallen below a predetermined value (S202 to S204).

[0093] The pair of electrodes 62 of the conductivity sensor 60 protrude upward from the inner bottom of the outer tub 20. Therefore, they gradually become submerged in water as tap water accumulates. Before the electrodes 62 are completely submerged, the surface area of ​​the electrodes 62 in contact with the tap water changes, causing the current flowing between the electrodes to vary, and thus the conductivity. Consequently, it is impossible to accurately measure the conductivity of the tap water itself.

[0094] When the pair of electrodes 62 are completely submerged in water, the change in the measured conductivity disappears, and the rate of change falls below a predetermined value. If it is determined that the rate of change in the conductivity has fallen below the predetermined value (S203: Yes), the control unit 301 determines the currently measured conductivity, i.e., the conductivity immediately below the predetermined value, as the conductivity of the tap water (hereinafter referred to as "water conductivity") (S205). This allows accurate measurement of the conductivity of the tap water itself.

[0095] Note that the conductivity after the rate of change becomes equal to or less than a predetermined value may be measured a plurality of times, and the average value of the plurality of conductivities may be determined as the water conductivity.

[0096] In this way, when the water conductivity is measured, the first water conductivity measurement process is completed. The water supply device 100 continues to supply water to the outer tub 20.

[0097] Returning to FIG. 5 , when the first water conductivity measurement process is completed, the control unit 301 checks whether a reference conductivity is stored in the storage unit 302 ( S103 ). If the reference conductivity is stored in the storage unit 302 ( S103 : Yes), the control unit 301 determines whether the water conductivity measured during the water conductivity measurement process is less than the reference conductivity ( S104 ).

[0098] If the storage unit 302 does not store the reference conductivity ( S103 : No), or if the water conductivity is lower than the reference conductivity stored in the storage unit 302 ( S104 : Yes), the control unit 301 determines the water conductivity as a new reference conductivity and stores the new reference conductivity in the storage unit 302 ( S105 ).

[0099] On the other hand, when the water conductivity is equal to or higher than the reference conductivity stored in the storage unit 302 ( S104 : No), the control unit 301 maintains the reference conductivity stored in the storage unit 302 .

[0100] Next, the control unit 301 executes the cleaning process (S106 to S108). First, the control unit 301 performs a water supply operation to store water containing detergent in the outer tub 20 (S106). The control unit 301 closes the second water supply valve 112 and maintains the first water supply valve 111 open. The water supply device 100 continues to supply water from the first water supply valve 111. Moreover, the control unit 301 activates the detergent injection device 100a to inject the amount of detergent set according to the load into the outer tub 20. It should be noted that when the detergent is injected, the second water supply valve 112 is opened, but the opening is maintained even after the detergent is injected. Then, when the water level in the outer tub 20 reaches the cleaning water level set according to the load, the control unit 301 closes the first water supply valve 111 and the second water supply valve 112 to stop the water supply.

[0101] Next, the control unit 301 performs a washing operation (S107). The control unit 301 activates the drive motor 31 to rotate the pulsator 24 alternately clockwise and counterclockwise, with the pulsator 24 occasionally stopping. The rotation of the pulsator 24 generates a water flow within the washing and dehydration tub 22. The force of this water flow, i.e., the mechanical force and the force of the detergent, cleans the laundry. When the specified washing time has elapsed, the control unit 301 stops the pulsator 24.

[0102] Next, the control unit 301 opens the drain valve 40 to initiate drainage (S108). The detergent-containing water stored in the outer tub 20 is discharged through the drain hose 41. The washing process ends when the water in the outer tub 20 is completely drained after a certain period of time has passed since the water level detector 50 detected the lowest water level. The drain valve 40 remains open.

[0103] It should be noted that, when the setting of not automatically dropping detergent into the detergent input device 100a is carried out, in the water supply action of cleaning process, the detergent input device 100a is inactive. In this case, the user manually drops detergent into the washing and dehydration barrel 22 when the water supply action is performed.

[0104] Next, the control unit 301 executes the intermediate spin process (S109). The control unit 301 activates the drive motor 31, causing the washing and dehydration tub 22 and the pulsator 24 to rotate integrally at a predetermined spin speed (e.g., 800 rpm). At this point, the control unit 301 increases the speed of the washing and dehydration tub 22 to the spin speed. Specifically, the control unit 301 performs steady-state rotation for a predetermined period of time, based on a first speed (e.g., 120 rpm) and a second speed (e.g., 240 rpm) that is higher than the first speed, during the speed increase.

[0105] The laundry is pressed against the inner circumference of the washing and dehydration barrel 22 by the centrifugal force generated by the rotation of the washing and dehydration barrel 22, squeezing water out of the laundry. The dehydration liquid from the laundry is discharged into the outer barrel 20 through the dehydration hole 22a and discharged to the outside of the machine through the drain hose 41.

[0106] When the rotation speed of the washing and dehydrating tub 22 reaches the dehydration rotation speed and the prescribed dehydration time has passed, the control unit 301 stops the washing and dehydrating tub 22. Thus, the intermediate dehydration process ends. The drain valve 40 remains open.

[0107] It should be noted that the dehydration time may also be the time from the start of rotation of the washing and dehydration barrel 22 to its stop, rather than the time from the speed of the washing and dehydration barrel 22 reaching the dehydration speed to the time of stopping the washing and dehydration barrel 22.

[0108] Then, the control unit 301 performs a spray rinsing process as the first rinsing process (S110). In the spray rinsing process, the control unit 301 opens the first water supply valve 111 and the second water supply valve 112 to supply water to the washing and dehydration barrel 22 by the water supply device 100, and drives the driving motor 31 to rotate the washing and dehydration barrel 22 and the pulsator 24 at a low speed as a whole.

[0109] The tap water released from the water inlet 121 of the water supply device 100 falls on the laundry that has passed the intermediate dehydration process and is close to the inner peripheral surface side of the washing and dehydration tub 22. The laundry fully absorbs the water, and the water that is not absorbed by the laundry flows out from the laundry together with the detergent. Thus, the laundry is rinsed.

[0110] When the predetermined rinsing time has passed, the control unit 301 stops the washing and dehydrating tub 22. Thus, the spray rinsing process ends.

[0111] Next, the control unit 301 performs an intermediate dehydration process (S111). The detergent remaining in the laundry is drained along with the water that has been fully contained in the laundry by the spray rinsing process. Thus, the laundry is rinsed while being dehydrated. When the intermediate dehydration process is completed, the drain valve 40 is closed.

[0112] Next, the control unit 301 executes the second water conductivity measurement process (S112). Thus, the water conductivity is measured in the same manner as in the first water conductivity measurement process.

[0113] The control unit 301 determines whether the water conductivity measured during the second water conductivity measurement is less than the reference conductivity (S113). If the water conductivity is less than the reference conductivity stored in the storage unit 302 (S114: Yes), the control unit 301 determines the water conductivity as a new reference conductivity and stores the new reference conductivity in the storage unit 302 (S114). On the other hand, if the water conductivity is greater than or equal to the reference conductivity stored in the storage unit 302 (S113: No), the control unit 301 maintains the reference conductivity stored in the storage unit 302.

[0114] Tap water supplied by the water supply device 100 passes through the washing and dehydration tub 22 and is stored in the outer tub 20. Therefore, the tap water is easily absorbed by the laundry contained in the washing and dehydration tub 22, and dirt attached to the laundry is easily mixed into the tap water. Therefore, during the first water conductivity measurement performed before the wash cycle, the tap water stored in the outer tub 20 is likely to contain dirt, and the measured water conductivity is easily affected by the amount of dirt. Furthermore, if detergent is manually added before the first water conductivity measurement, the measured water conductivity is also easily affected by the detergent.

[0115] On the other hand, during the second water conductivity measurement process, which is performed after the intermediate dehydration process following the first rinsing process, dirt from the laundry is removed during the washing process, so the measured water conductivity is less likely to be affected by the amount of dirt than during the first water conductivity measurement process. Furthermore, when detergent is manually added, the water conductivity measured during the first water conductivity measurement process is more likely to be affected by the detergent, so during the second water conductivity measurement process, the effect of the detergent on the water conductivity may be smaller than during the first water conductivity measurement process. It should be noted that when detergent is automatically added by the detergent-dispensing device 100a, the water conductivity measured during the first water conductivity measurement process is less likely to be affected by the detergent, so during the second water conductivity measurement process, since detergent used during the washing process may remain, the effect of the detergent on the water conductivity may be greater than during the first water conductivity measurement process.

[0116] For this reason, if the tap water stored in the outer tub 20 is not likely to contain dirt from laundry, or if detergent is manually added automatically, the water conductivity measured in the first water conductivity measurement may be lower than the water conductivity measured in the second water conductivity measurement. On the other hand, if the tap water stored in the outer tub 20 is likely to contain dirt from laundry, or if detergent is manually added, the water conductivity measured in the second water conductivity measurement may be lower than the water conductivity measured in the first water conductivity measurement.

[0117] In this embodiment, the control unit 301 executes steps S103-S105 and S112-S114 to determine the smaller of the two water conductivities measured during the first and second water conductivity measurements as the reference conductivity. Thus, the water conductivity (tap water conductivity) close to its original value, where the effects of laundry dirt and detergent are minimal, can be set as the reference conductivity.

[0118] Furthermore, in this embodiment, if the water conductivity measured during the water conductivity measurement process is less than the reference conductivity stored in the storage unit 302, the control unit 301 determines this water conductivity as the new reference conductivity. Thus, the minimum water conductivity between the water conductivity measured in the first and second water conductivity measurement processes is set as the reference conductivity. Therefore, even in situations where the tap water stored in the outer tub 20 may be affected by dirt and detergent from the laundry, the water conductivity (tap water conductivity) at which the effects of dirt and detergent from the laundry are minimized and close to the original value due to repeated washing operations is set as the reference conductivity.

[0119] Next, the control unit 301 executes a water storage and rinsing process as the second rinse process (S115-S117). First, the control unit 301 supplies water to the outer tub 20 (S115). The control unit 301 maintains the first and second water supply valves 111, 112 open, continuing the water supply to the outer tub 20 that began during the second water conductivity measurement process. When the water level in the outer tub 20 reaches the rinse level set according to the load, the control unit 301 closes the first and second water supply valves 111, 112, stopping the water supply.

[0120] Next, the control unit 301 performs a water storage and rinsing operation (S116). The control unit 301 activates the drive motor 31, causing the pulsator 24 to rotate alternately clockwise and counterclockwise, with intermittent stops. The rotation of the pulsator 24 generates a water flow within the washing and dehydration tub 22, which rinses the laundry. This removes any remaining detergent from the laundry. When the specified rinsing time has elapsed, the control unit 301 stops the pulsator 24.

[0121] Next, the control unit 301 opens the drain valve 40 to drain the water (S117). When the water in the outer tub 20 is completely drained, the water storage and rinsing process ends. The drain valve 40 remains open.

[0122] Then, the control unit 301 performs the final dehydration process (S118). The control unit 301 causes the drive motor 31 to rotate the washing and dehydration barrel 22 and the pulsator 24 integrally at a prescribed dehydration speed. In the final dehydration process, the dehydration speed (for example, 1000rpm) is set to a higher speed than the intermediate dehydration process. Same as the intermediate dehydration process, the control unit 301 causes the speed stage of the washing and dehydration barrel 22 to rise to the dehydration speed. The dehydration liquid from the washing is discharged into the outer tub 20 through the dehydration hole 22a of the washing and dehydration barrel 22.

[0123] In the final spin cycle, a spin time longer than the intermediate spin cycle is set. When the spin cycle speed reaches the spin speed and the spin time has elapsed, the control unit 301 stops the washing and dehydration tub 22. Thus, the final spin cycle ends. When the final spin cycle ends, the drain valve 40 is closed.

[0124] During the final spin-drying process, the control unit 301 executes a dewatering conductivity measuring process in which the conductivity sensor 60 measures the conductivity of dewatered liquid squeezed out of the laundry and stored in the outer tub 20 ( S119 ).

[0125] 7 , the control unit 301 closes the drain valve 40 ( S301 ), whereby the drain liquid discharged into the outer tub 20 is easily accumulated at the bottom of the outer tub 20 .

[0126] The control unit 301 measures the conductivity of the conductivity sensor 60 at regular sampling intervals, such as 0.1 second intervals, and compares the previously measured conductivity with the currently measured conductivity to monitor whether the rate of change in conductivity has fallen below a predetermined value (S302-S304). As liquid is removed and stored within the outer tub 20, the pair of electrodes 62 of the conductivity sensor 60 gradually become submerged.

[0127] When the pair of electrodes 62 are completely submerged, the change in the measured conductivity disappears, and the rate of change falls below a predetermined value. If it is determined that the rate of change in the conductivity has fallen below the predetermined value (S303: Yes), the control unit 301 determines the currently measured conductivity, i.e., the conductivity immediately below the predetermined value, as the conductivity of the dewatered liquid (hereinafter referred to as "dewatered liquid conductivity") (S305). This allows accurate measurement of the conductivity of the dewatered liquid itself.

[0128] Note that the conductivity after the rate of change becomes equal to or less than a predetermined value may be measured a plurality of times, and the average value of the plurality of conductivities may be determined as the deliquescence conductivity.

[0129] The control unit 301 opens the drain valve 40 ( S306 ), whereby the drain liquid discharged into the outer tub 20 is discharged to the outside of the machine through the drain hose 41 .

[0130] It should be noted that the deliquid conductivity measurement process starts when the washing and dehydrating tub 22 starts rotating and ends at least when the rotation speed of the washing and dehydrating tub 22 reaches the dehydration rotation speed.

[0131] Returning to Figure 5 , after the dewatering conductivity measurement process is completed, and further, at the end of the final dehydration process, the control unit 301 corrects the dewatering conductivity measured during the dewatering conductivity measurement process using the reference conductivity stored in the storage unit 302. Specifically, the control unit 301 subtracts the reference conductivity from the dewatering conductivity to determine the corrected dewatering conductivity (hereinafter referred to as the "corrected conductivity") (S120). For conditions in which the dewatering conductivity remains constant, the greater the reference conductivity, the smaller the corrected conductivity. The corrected conductivity is a value that eliminates the effects of varying tap water properties and accurately reflects the amount of detergent remaining in the laundry.

[0132] Next, the control unit 301 determines whether the corrected conductivity is greater than a predetermined threshold value (S121). If a large amount of detergent remains in the laundry and the rinsing is insufficient, the corrected conductivity is greater than the threshold value.

[0133] When the corrected electrical conductivity is equal to or lower than the threshold value ( S121 : NO), it is considered that the washing process is not insufficiently rinsed, and thus the control unit 301 ends the washing operation without adding a rinse cycle.

[0134] On the other hand, if the corrected conductivity is greater than the threshold (S121: YES), it is considered that the laundry is under-rinsed, so the control unit 301 executes a water storage rinsing process as an additional rinsing process. Specifically, the control unit 301 performs a water supply operation, a water storage rinsing operation, and a water discharge operation (S122-S124), thereby resolving the problem of under-rinsing of the laundry.

[0135] When the additional rinsing process is completed, the control unit 301 performs a final spin-drying process (S125) and ends the washing operation.

[0136] <Effects of implementation>

[0137] According to this embodiment, during the spin cycle following the rinsing cycle, the control unit 301 performs a dewatering conductivity measurement process, in which conductivity sensor 60 measures the conductivity of dewatered liquid squeezed from the laundry and stored in the outer tub 20. The control unit then adjusts the number of rinsing cycles based on the dewatering conductivity. Specifically, the control unit 301 measures the dewatering conductivity during the final spin cycle. If the dewatering conductivity determines that rinsing is insufficient, the control unit 301 adds a rinse cycle after the final spin cycle. If the dewatering conductivity determines that rinsing is sufficient, the control unit 301 does not add a rinse cycle after the final spin cycle.

[0138] This configuration directly measures the conductivity of water that may contain detergent flowing from the laundry. Unlike measuring the conductivity of rinsing water stored in outer tub 20, the amount of detergent remaining in the laundry is reliably reflected in the measured conductivity. This allows for highly accurate determination of the rinsing status of the laundry, allowing for additional rinsing steps if rinsing is insufficient, ensuring that the laundry is fully rinsed.

[0139] Furthermore, according to this embodiment, the control unit 301 activates the water supply device 100 to store tap water in the outer tub 20. The conductivity sensor 60 then performs a water conductivity measurement process to measure the conductivity of the tap water, determining the conductivity of the tap water as a reference conductivity. The control unit 301 then corrects the conductivity of the drained water so that the greater the reference conductivity, the lower the conductivity of the drained water. The number of rinse cycles is adjusted based on the corrected conductivity of the drained water.

[0140] According to this configuration, by correcting the conductivity of the drained water using the reference conductivity, the influence of differences in the properties of tap water can be eliminated, thereby enabling the amount of detergent remaining in the laundry to be determined with high accuracy.

[0141] Furthermore, according to this embodiment, during the water supply during the washing process, the control unit 301 operates the detergent dispenser 100a and the water supply device 100 to store water containing detergent in the outer tub 20. The control unit 301 then performs a first water conductivity measurement process before the detergent dispenser 100a dispenses detergent into the outer tub 20.

[0142] This configuration prevents detergent introduced by detergent injector 100a from being mixed into tap water measured in the first water conductivity measurement process, and prevents the conductivity of tap water with a high detergent concentration from being set as the reference conductivity.

[0143] Moreover, according to this embodiment, the control unit 301 stores the reference conductivity in the storage unit 302. When the conductivity of the tap water measured during the water conductivity measurement process is lower than the reference conductivity stored in the storage unit 302, the conductivity of the tap water is determined as the new reference conductivity.

[0144] With this configuration, the lowest conductivity of the tap water measured during the previous water conductivity measurement process is set as the reference conductivity. Therefore, even if the tap water stored in the outer tub 20 may be affected by dirt and detergent in the laundry, the conductivity of the tap water that has approached its original value through repeated washing operations is set as the reference conductivity. This allows for more accurate determination of the amount of detergent remaining in the laundry.

[0145] Furthermore, according to this embodiment, the control unit 301 performs a first water conductivity measurement process before the washing process and a second water conductivity measurement process after the spin process (intermediate spin process) following the first rinsing process. The control unit 301 then determines the smaller of the two tap water conductivities measured in the first and second water conductivity measurement processes as the reference conductivity, and performs the dewatering conductivity measurement process during the spin process (final spin process) following the second rinsing process.

[0146] With this configuration, the tap water conductivity measured in the first and second water conductivity measurements, whichever is closer to its original value and less affected by laundry dirt and detergent, can be set as the reference conductivity. This allows for more accurate determination of the amount of detergent remaining in the laundry.

[0147] Furthermore, according to this embodiment, the conductivity sensor 60 includes a pair of electrodes 62 arranged to protrude upward from the inner surface of the bottom portion 202 of the outer tub 20. During the water conductivity measurement process, the control unit 301 monitors the rate of change in the conductivity measured by the conductivity sensor 60 and determines the conductivity after the rate of change falls below a predetermined value as the conductivity of the tap water. Furthermore, during the dewatering conductivity measurement process, the control unit 301 monitors the rate of change in the conductivity measured by the conductivity sensor 60 and determines the conductivity after the rate of change falls below the predetermined value as the dewatering conductivity.

[0148] According to this configuration, the conductivity measured when the pair of electrodes 62 are completely submerged is determined as the conductivity of the tap water and the conductivity of the drain liquid, so the conductivity of the tap water itself and the conductivity of the drain liquid itself can be accurately measured.

[0149] As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment at all, Moreover, embodiment of this invention can also be variously modified other than what was mentioned above.

[0150] <Change Example 1>

[0151] In the above embodiment, after the final spin-drying process is completed, it is determined whether to add the rinsing process based on the conductivity of the dehydrated liquid.

[0152] In contrast, in this modified example, during the final spin cycle, a determination is made based on the conductivity of the dehydrated liquid whether to add a rinse cycle. Furthermore, if a determination is made that an additional rinse cycle is added, the final spin cycle is altered by reducing the spin speed and / or shortening the spin time.

[0153] Fig. 8 is a flowchart showing the control process performed by control unit 301 during the washing operation according to Modification 1. Fig. 9 is a flowchart showing the control process performed by control unit 301 during the rinse addition determination process included in the washing operation according to Modification 1.

[0154] 8 , in the final spin-drying process, when the deliquescence conductivity measurement process is completed ( S119 ), the control unit 301 executes the additional rinsing determination process ( S126 ).

[0155] 9 , the control unit 301 uses the reference conductivity stored in the storage unit 302 to correct the deionized water conductivity measured during the deionized water conductivity measurement process. Specifically, the control unit 301 subtracts the reference conductivity from the deionized water conductivity to determine the corrected conductivity (S401). The control unit 301 then determines whether the corrected conductivity is greater than a threshold value (S402).

[0156] When the corrected electrical conductivity is equal to or lower than the threshold value ( S402 : No), it is considered that the rinse is not insufficient, and the control unit 301 ends the rinse addition determination process.

[0157] On the other hand, if the corrected conductivity is greater than the threshold value ( S402 : YES), it is considered that the rinsing is insufficient, and the control unit 301 sets an additional flag ( S403 ). The additional flag is included in the control unit 301 , for example.

[0158] Furthermore, the control unit 301 changes the spin speed to reduce the final spin process, and changes it to shorten the spin time of the final spin process (S404). For example, the spin speed and spin time are changed to the intermediate spin process. In this case, the final spin process is actually changed to the intermediate spin process. Afterwards, the control unit 301 ends the rinse additional determination process. It should be noted that the rinse additional determination process ends at least when the rotation speed of the washing and dehydration barrel 22 reaches the spin speed.

[0159] It should be noted that the control unit 301 may change only one of the spin speed and the spin time in the final spin process.

[0160] Returning to Figure 8 , after the additional rinse determination process is completed and further to the final spin cycle, the control unit 301 determines whether the additional flag is set (S127). If the additional flag is not set (S127: No), the control unit 301 ends the washing operation. On the other hand, if the additional flag is not set (S127: No), the control unit 301 executes the additional rinsing process (S122-S124) followed by the final spin cycle (S125), thereby ending the washing operation.

[0161] According to the configuration of this modified example, by adding a rinse cycle and then performing a final rinse cycle again after the rinse cycle, the final spin cycle before the additional rinse cycle is modified by reducing the spin speed and / or shortening the spin time. This shortens the time required for the final spin cycle before the additional rinse cycle, and reduces the increase in washing operation time caused by the additional rinse cycle and the final spin cycle.

[0162] <Change Example 2>

[0163] In the above embodiment, the control unit 301 measures the conductivity of the deliquescence during the final dehydration process. When it is determined that the rinsing is insufficient based on the conductivity of the deliquescence, a rinsing process is added after the final dehydration process. When it is determined that the rinsing is sufficient based on the conductivity of the deliquescence, a rinsing process is not added after the final dehydration process.

[0164] In contrast, in this variation, the control unit 301 measures the conductivity of the deliquescence during the intermediate dehydration process subsequent to the first rinsing process. When it is determined based on the conductivity of the deliquescence that rinsing may not be sufficient in the remaining rinsing process, two rinsing processes are performed after the intermediate dehydration process. When it is determined based on the conductivity of the deliquescence that rinsing can be sufficient in the remaining rinsing process, one rinsing process is performed after the intermediate dehydration process.

[0165] FIG. 10 is a flowchart showing a control process performed by control unit 301 during the washing operation according to Modification 2. FIG.

[0166] 10 , when the shower rinsing process as the first rinsing process ends ( S110 ), the control unit 301 performs an intermediate dehydration process ( S130 ). Furthermore, the control unit 301 performs a dehydration conductivity measurement process ( S131 ) during the intermediate dehydration process to measure dehydration conductivity.

[0167] After the dewatering conductivity measurement process is completed, and further, after the intermediate dehydration process is completed, the control unit 301 subtracts the reference conductivity from the dewatering conductivity to calculate a corrected conductivity (S132) and determines whether the corrected conductivity is greater than a predetermined threshold (S133). The threshold in this modified example is set to be greater than the threshold in the above-described embodiment.

[0168] When the corrected conductivity is greater than the threshold value (S133: Yes), rinsing may be insufficient in the remaining rinsing process. Therefore, in order to perform two rinsing processes, the control unit 301 sequentially performs the water storage rinsing process (S134~S136), the intermediate dehydration process (S137), the water storage rinsing process (S138~S140) and the final dehydration process (S141).

[0169] On the other hand, when the corrected conductivity is below the threshold (S133: No), sufficient rinsing is possible in the remaining one rinsing process, so in order to perform one rinsing process, the control unit 301 sequentially performs the water storage rinsing process (S138-S140) and the final dehydration process (S141).

[0170] According to the configuration of this modification, as in the above embodiment, the rinsing status of the laundry can be determined with high accuracy, and if rinsing is insufficient, a rinsing step can be added to allow the laundry to be rinsed clean.

[0171] It should be noted that in this modified example, the detergent dispenser 100a of the water supply device 100 serves as a liquid agent dispenser and, in addition to the detergent box 170, may also include a softener box for storing liquid softener. Like the detergent box 170, the softener box is connected to the second water supply passage 140 via a three-way valve. In this case, during the final rinse cycle (water storage rinse cycle) performed before the final spin cycle, the softener in the softener box is automatically dispensed into the outer tub 20.

[0172] Other changes

[0173] In the above embodiment, the water conductivity measurement process is performed twice: before the washing process and after the intermediate spin cycle following the rinsing process. However, the water conductivity measurement process may be performed only once: before the washing process or after the intermediate spin cycle following the rinsing process. In the case where the water conductivity measurement process is performed only once, as in the above embodiment, when the water supply device 100 includes a detergent dispenser 100a that automatically dispenses detergent into the detergent box 170, it is ideal to perform the water conductivity measurement process before the washing process. On the other hand, when the water supply device 100 includes a detergent box that dispenses a single amount of detergent midway through the water supply path into the outer tub 20, and tap water must pass through the detergent box when water is supplied from the water supply device 100, in order to avoid being affected by the detergent dispensed from the detergent box into the outer tub 20, it is ideal to perform the water conductivity measurement process after the intermediate spin cycle following the rinsing process.

[0174] Furthermore, in the above embodiment, a spray rinsing process is performed as the first rinsing process. However, a water storage rinsing process may also be performed as the first rinsing process. However, when a spray rinsing process is performed as the first rinsing process, insufficient rinsing is more likely to occur than when a water storage rinsing process is performed as the first rinsing process. Therefore, it is of great significance for the fully automatic washing machine 1 to have a function of adjusting the number of rinses based on the conductivity of the liquid extracted from the laundry.

[0175] Furthermore, the structure and arrangement of the conductivity sensor 60 are not limited to those of the above-described embodiment, and any structure and arrangement may be used as long as the conductivity of the tap water or deionized water stored in the outer tub 20 can be measured.

[0176] Furthermore, the configuration of the detergent dispenser 100a is not limited to that of the above-described embodiment. For example, the detergent dispenser 100a may be provided separately from the water supply device 100 and not included in the water supply device 100.

[0177] Furthermore, in the above embodiment, an example of the present invention being applied to a fully automatic washing machine 1 is shown. However, the present invention can also be applied to a fully automatic washer-dryer equipped with a clothes drying function. Furthermore, the present invention can also be applied to a drum-type washing machine and a drum-type washer-dryer that have a horizontally-axis-shaped drum as an inner drum within an outer drum. In a drum-type washing machine and a drum-type washer-dryer, a washing unit is formed by a drum and a drive motor that rotates the drum. The rotation of the drum causes the laundry to tumble, thereby applying mechanical force to the laundry.

[0178] Furthermore, various modifications can be made to the embodiments of the present invention as appropriate within the scope of the technical concept shown in the claims.

Claims

1. A washing machine, characterized in that: have: The outer barrel is arranged inside the box body and stores water; a washing unit, comprising an inner tub disposed in the outer tub and a driving motor, and applying mechanical force to the laundry contained in the inner tub based on the torque generated by the driving motor; a control unit for controlling the operation of the washing unit to perform a washing operation including the following processes: a washing process for washing the laundry with water containing detergent, a rinsing process for rinsing the laundry with water, and a dehydrating process for dehydrating the laundry by generating centrifugal force through the rotation of the inner tub, and A conductivity sensor is used to measure the conductivity of the water stored at the bottom of the outer barrel, The control unit performs a dewatering conductivity measuring process of measuring the conductivity of dewatered liquid squeezed out of the laundry and stored in the outer tub by the conductivity sensor in the dewatering process subsequent to the rinsing process. The control unit adjusts the number of times of the rinsing process based on the conductivity of the dewatering liquid.

2. The washing machine according to claim 1, characterized in that: It also has a water supply device, including a water supply valve connected to a faucet, to supply tap water into the outer barrel, The control unit executes a water conductivity measuring process in which the water supply device is operated to store tap water in the outer tub and the conductivity of the tap water is measured by the conductivity sensor. The control unit determines the conductivity of the tap water as a reference conductivity, The control unit corrects the conductivity of the deliquescence so that the conductivity of the deliquescence decreases as the reference conductivity increases. The control unit adjusts the number of times of the rinsing process based on the corrected conductivity of the dewatering liquid.

3. The washing machine according to claim 2, characterized in that: It also includes a detergent feeding device, including a detergent box for storing liquid detergent. The detergent in the box is automatically put into the outer barrel. The control unit operates the detergent injector and the water supply device during the water supply in the washing process to store water containing detergent in the outer tub. The control unit performs the water conductivity measuring process before the detergent is introduced into the outer tub by the detergent introducing device.

4. The washing machine according to claim 2 or 3, characterized in that: The device further comprises a storage unit. The control unit stores the reference conductivity in the storage unit, When the conductivity of the tap water measured in the water conductivity measurement process is lower than the reference conductivity stored in the storage unit, the control unit determines the conductivity of the tap water as the new reference conductivity.

5. The washing machine according to claim 2, characterized in that: The control unit performs the first water conductivity measurement process before the cleaning process. The control unit performs the second water conductivity measuring process after the dehydration process subsequent to the first rinsing process, The control unit determines the smaller conductivity of the two conductivities of the tap water measured in the first water conductivity measurement process and the second water conductivity measurement process as the reference conductivity, The control unit performs the dewatering conductivity measuring process in the dehydration process subsequent to the second rinsing process.

6. The washing machine according to claim 2, characterized in that: The conductivity sensor includes: a pair of electrodes configured to protrude upward from the inner surface of the bottom portion of the outer barrel; The control unit monitors the change rate of the conductivity measured by the conductivity sensor during the water conductivity measurement process, and determines the conductivity after the change rate becomes less than a predetermined value as the conductivity of the tap water. The control unit monitors a change rate of the conductivity measured by the conductivity sensor during the measurement of the deliquescence conductivity, and determines the conductivity after the change rate becomes equal to or less than the predetermined value as the deliquescence conductivity.

7. The washing machine according to claim 1, characterized in that: The washing operation includes: at least two rinsing processes, an intermediate dehydration process subsequent to the first rinsing process, and a final dehydration process subsequent to the second rinsing process, in which the inner tub rotates at a higher dehydration speed for a longer dehydration time than in the intermediate dehydration process. The control unit performs the dehydration conductivity measurement process during the final dehydration process. When the rinsing process is added based on the conductivity of the dewatered liquid, the control unit changes the dehydration speed in the final dehydration process being executed by reducing the dehydration speed and / or shortening the dehydration time. The control unit performs the final spin-drying process after the additional rinsing process.

Images