Washing machine

Abstract

To provide a washing machine which can finish laundry in a suitably dewatered state irrespective of the cloth quality.SOLUTION: A fully automatic washing machine 1 includes: an outer tub which is arranged in a housing, and in which water is stored; a washing and dewatering tub which is rotatably arranged in the outer tub, and in which laundry is stored; a drive motor 31 for driving the washing and dewatering tub; a control part 101 for controlling the drive motor 31, and for executing a dewatering step of rotating the washing and dewatering tub for predetermined dewatering time at predetermined dewatering rotational frequency; and a water level detection part 60 for detecting the water level in the outer tub. The control part 101 determines the cloth quality of the laundry in the washing and dewatering tub based on the water level in the outer tub changing according to the amount of dewatered liquid per unit time from the laundry, during the period when the rotation of the washing and dewatering tub in a final dewatering step rises, and sets the dewatering time and / or dewatering rotational frequency at the value according to the determined cloth quality.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] Patent Document 1 describes a drum-type washing machine that, during the spin-drying process, determines the fabric quality of the laundry and changes the spin-drying time depending on whether the laundry absorbs water easily (such as cotton) or does not absorb water easily (such as synthetic fibers).

[0003] In the drum type washing machine, the spin-drying process includes a preliminary spin-drying process in which the drum rotates at a low speed several times before the main spin-drying process in which the drum rotates at a high speed. The fabric quality is determined based on the difference in the brake time between each preliminary spin-drying process. The smaller the difference in the brake time, the more the laundry is determined to have a low water absorption rate, and the spin-drying time of the main spin-drying process is shortened. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-128635 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the drum type washing machine described above, it is difficult to determine the fabric quality during the spin-drying process that does not include the preliminary spin-drying process. Therefore, it is conceivable to adopt a configuration that can determine the fabric quality of the laundry by a method other than the determination based on the difference in the brake time during the spin-drying process.

[0006] An object of the present invention is to provide a washing machine capable of finishing laundry in a suitable dehydration state regardless of the condition of the fabric of the laundry. [Means for solving the problem]

[0007] A washing machine according to a main aspect of the present invention includes an outer tub arranged in a housing and storing water, an inner tub arranged rotatably in the outer tub and storing laundry, a drive motor for driving the inner tub, a control unit for controlling the drive motor to execute a spin-drying process in which the inner tub is rotated for a predetermined spin-drying time and a predetermined spin-drying rotation speed, and a water level detection unit for detecting a water level in the outer tub. Here, the control unit determines the fabric quality of the laundry in the inner tub based on the water level in the outer tub, which changes according to the amount of liquid removed from the laundry per unit time, during a period when the rotation of the inner tub starts up in a final spin-drying process, and sets the spin-drying time and / or the spin-drying rotation speed to a value according to the determined fabric quality.

[0008] The dehydration time may be, for example, the time from when the rotation speed of the inner tub reaches the dehydration rotation speed until the inner tub stops, or the time from when the inner tub starts until it stops.

[0009] According to the washing machine of this embodiment, when the laundry in the inner tub contains a lot of clothes with fabrics that easily absorb water, the spin-drying time can be relatively long and the spin-drying rotation speed can be relatively high, so that the laundry is less likely to be insufficiently dehydrated. Furthermore, when the laundry in the inner tub contains a lot of clothes with fabrics that do not easily absorb water, the spin-drying time can be relatively short and the spin-drying rotation speed can be relatively low, so that the laundry is less likely to be over-dehydrated. Therefore, it is possible to finish the laundry in a suitable spin-drying state regardless of the state of its fabric.

[0010] In the washing machine according to the present aspect, the water level detector may have a pair of electrodes disposed on the bottom surface of the outer tub and may be configured to detect the electrical conductivity between the electrodes that varies depending on the water level in the outer tub. In this case, the control unit may be configured to determine the fabric type based on the electrical conductivity detected by the water level detector.

[0011] According to the above configuration, the water level detector can detect the water level in the outer tub, which changes according to the amount of drainage per unit time, based on the electrical conductivity generated between the electrodes.

[0012] When the water level detection unit is configured to detect the conductivity between the electrodes as described above, the device may further include a drain outlet provided on the bottom of the outer tub and a drain valve for opening and closing the drain outlet. In this case, the control unit may be configured to close the drain valve to store the liquid removed from the laundry in the outer tub to completely submerge the pair of electrodes, set the conductivity detected by the water level detection unit after the pair of electrodes are completely submerged as a reference conductivity, open the drain valve after the pair of electrodes are completely submerged, set the conductivity detected by the water level detection unit after the drain valve is opened as a judged conductivity, compare a judged water level value obtained by dividing the judged conductivity by the reference conductivity with a predetermined threshold value to judge the fabric quality, and when the judged water level value is greater than the threshold value, make the dewatering time longer and / or increase the dewatering rotation speed compared to when the judged water level value is equal to or less than the threshold value.

[0013] According to the above configuration, when the laundry contains a large amount of clothes made of fabrics that easily absorb water, such as cotton, the amount of liquid removed per unit time increases, and the water level in the outer tub is less likely to drop after the drain valve is opened, resulting in a high determined conductivity. As a result, when the determined water level value becomes greater than the threshold value, the spin time is lengthened and / or the spin rotation speed is increased. On the other hand, when the laundry contains a large amount of clothes made of fabrics that do not easily absorb water, such as chemical fibers, the amount of liquid removed per unit time decreases, and the water level in the outer tub is more likely to drop after the drain valve is opened, resulting in a low determined conductivity. As a result, when the determined water level value becomes equal to or less than the threshold value, the spin time is shortened and / or the spin rotation speed is reduced.

[0014] The water level judgment value is expressed as a ratio of the water level of the dehydration, which changes according to the amount of dehydration per unit time, to the upper limit water level that the water level detection unit can detect for the same dehydration, so it is not affected by the conductivity of the dehydration itself and is likely to be an accurate value. Therefore, by comparing the water level judgment value with a threshold value, the fabric quality can be judged with high accuracy and the dehydration time and / or dehydration rotation speed can be adjusted. This makes it possible to finish the laundry in a more optimal dehydration state.

[0015] When the above configuration is adopted, the control unit can be further configured to measure the drainage capacity when draining water from the outer tank before the final spin-drying process, and to set the threshold value to a larger value as the drainage capacity is lower.

[0016] With this configuration, even if the drainage capacity from within the outer tub affects the change in the water level within the outer tub, the threshold value is changed according to the drainage capacity, making it possible to determine the fabric quality with high accuracy.

[0017] When the water level detection unit is configured to detect the conductivity between the electrodes as described above, the control unit may further include a drain port provided on the bottom of the outer tub and a drain valve for opening and closing the drain port. In this case, the control unit may be configured to detect the conductivity with the water level detection unit in a state in which the pair of electrodes are completely submerged in the water in the outer tub immediately before or during drainage in a rinsing step performed before the final spin-drying step, and set the detected conductivity as a reference conductivity in the final spin-drying step, which is detected by the water level detection unit after the drain valve is closed, and set the conductivity corresponding to the water level according to the amount of liquid removed per unit time detected by the water level detection unit after the drain valve is closed as a judgment conductivity, and compare a judgment water level value obtained by dividing the judgment conductivity by the reference conductivity with a predetermined threshold value to judge the fabric quality, and when the judgment water level value is greater than the threshold value, make the spin-drying time longer and / or increase the spin-drying rotation speed compared to when the judgment water level value is equal to or less than the threshold value.

[0018] According to the above configuration, when the laundry contains many clothes made of fabric that easily absorbs water, the amount of liquid removed per unit time increases, and the water level in the outer tub is more likely to rise after the drain valve is closed, resulting in a higher determined conductivity. As a result, when the determined water level value becomes greater than the threshold value, the spin time is lengthened and / or the spin rotation speed is increased. On the other hand, when the laundry contains many clothes made of fabric that does not easily absorb water, the amount of liquid removed per unit time decreases, and the water level in the outer tub is less likely to rise after the drain valve is closed, resulting in a lower determined conductivity. As a result, when the determined water level value becomes equal to or less than the threshold value, the spin time is shortened and / or the spin rotation speed is reduced.

[0019] The water level judgment value is expressed as a ratio of the deliquor water level, which changes according to the amount of deliquor per unit time, to the upper limit water level that the water level detection unit can detect using water after rinsing of the same quality as the deliquor, so it is less affected by the conductivity of the deliquor itself and tends to be an accurate value. Therefore, by comparing the water level judgment value with a threshold value, the fabric quality can be judged with high accuracy and the dehydration time and / or dehydration rotation speed can be adjusted. This makes it possible to finish the laundry in a more suitable dehydration state.

[0020] When the water level detector detects the electrical conductivity between the electrodes as described above, the washing machine may further include a load detector that detects the load of the laundry contained in the inner tub. In this case, the control unit may be configured to set the threshold value to a larger value as the load increases.

[0021] According to the above configuration, even if the laundry load affects the amount of liquid removed per unit time, the threshold value is changed according to the load, so that the fabric quality can be determined with high accuracy. Effect of the Invention

[0022] According to the present invention, a washing machine capable of finishing laundry to a suitable dehydration state regardless of the condition of the fabric of the laundry can be provided.

[0023] The effects and significance of the present invention will become clearer from the following description of the embodiments. However, the following embodiment is merely an example of how the present invention can be put into practice, and the present invention is not limited to the embodiment described below. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a side cross-sectional view of a fully automatic washing machine according to an embodiment. [Diagram 2] Fig. 2(a) is a plan cross-sectional view of the outer tub according to the embodiment, and Fig. 2(b) is a side cross-sectional view of the outer tub and the periphery of the water level detector taken along line AA' in Fig. 2(a). [Diagram 3] FIG. 3 is a block diagram showing a configuration of a fully automatic washing machine according to an embodiment. [Figure 4] FIG. 4 is a flowchart showing the flow of a washing operation according to the embodiment. [Diagram 5] FIG. 5 is a flowchart showing a spin-drying control process executed by a control unit in a spin-drying step according to an embodiment. [Figure 6] FIG. 6 is a flowchart showing a dehydration operation condition determination process executed by the control unit in the final dehydration step according to the embodiment. [Figure 7] FIG. 7 is a flowchart showing a reference electrical conductivity acquisition process included in a dehydration operation condition determination process according to an embodiment. [Figure 8] FIG. 8 is a flowchart showing the determined electrical conductivity acquisition process included in the dehydration operation condition determination process according to the embodiment. [Figure 9] FIG. 9 is a diagram illustrating an example of a threshold determination table according to the embodiment. [Figure 10] Fig. 10(a) is a flowchart showing a dehydration operation condition determination process executed by a control unit in a final dehydration step according to Modification 1. Fig. 10(b) is a diagram showing an example of a threshold determination table according to Modification 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, a fully automatic washing machine 1, which is one embodiment of a washing machine of the present invention, will be described with reference to the drawings.

[0026] FIG. 1 is a side cross-sectional view of a fully automatic washing machine 1. As shown in FIG.

[0027] The fully automatic washing machine 1 has a housing 10 which constitutes its exterior. The housing 10 includes a rectangular cylindrical body 11 with upper and lower open faces, a top plate 12 which covers the top face of the body 11, and a foot stand 13 which supports the body 11. A laundry insertion opening 14 is formed in the top plate 12. The laundry insertion opening 14 is covered by an upper lid 15 which can be opened and closed.

[0028] An outer tank 20 with an open top is disposed within the housing 10. The outer tank 20 is elastically suspended and supported by four suspension rods 21 equipped with vibration isolation devices. The outer tank 20 has a substantially cylindrical peripheral surface portion 201 and a substantially disk-shaped bottom surface portion 202.

[0029] A washing / dehydrating tub 22 with an open top is disposed within the outer tub 20. The washing / dehydrating tub 22 has a substantially cylindrical peripheral surface portion 22a and a substantially disk-shaped bottom surface portion 22b, and rotates about a rotation axis extending in the vertical direction. A large number of dehydration holes 22c are formed on the peripheral surface portion 22a of the washing / dehydrating tub 22 all around. The washing / dehydrating tub 22 corresponds to the "inner tub" of the present invention.

[0030] A balance ring 23 is provided on the upper part of the washing / drying tub 22. A pulsator 24 is rotatably disposed on the bottom part of the washing / drying tub 22. A plurality of blades 24a are provided radially on the surface of the pulsator 24.

[0031] A drive unit 30 that generates torque to drive the washing / spinning tub 22 and the pulsator 24 is disposed on the outside of the bottom surface 202 of the outer tub 20. The drive unit 30 includes a drive motor 31 and a transmission mechanism 32. The transmission mechanism 32 has a clutch mechanism 32a, and by switching operation of the clutch mechanism 32a, the torque of the drive motor 31 is transmitted only to the pulsator 24 to rotate only the pulsator 24 in the washing step and the rinsing step, and the torque of the drive motor 31 is transmitted to the pulsator 24 and the washing / spinning tub 22 to rotate the pulsator 24 and the washing / spinning tub 22 integrally in the spinning step.

[0032] A drain outlet 203 is provided on the bottom surface 202 of the outer tub 20. A drain unit 40 is connected to the drain outlet 203. The drain unit 40 includes a drain valve 41 that opens and closes the drain outlet 203, and a drain hose 42 connected to the drain valve 41. When the drain valve 41 is opened, water stored in the washing and spin-drying tub 22 and the outer tub 20 is drained outside the machine through the drain hose 42.

[0033] A water supply unit 50 for supplying tap water into the washing and spin-drying tub 22, i.e., the outer tub 20, is disposed at the rear of the top panel 12. The water supply unit 50 has a water supply valve 51. A water inlet 51a of the water supply valve 51 is connected to a water faucet via a water supply hose. When the water supply valve 51 is opened, tap water from the water faucet flows through a water supply passage 52 and is supplied from a water inlet 53 into the washing and spin-drying tub 22, i.e., the outer tub 20.

[0034] Fig. 2(a) is a plan cross-sectional view of the outer tub 20. Fig. 2(b) is a side cross-sectional view of the outer tub 20 around the water level detection unit 60, taken along line AA' in Fig. 2(a).

[0035] A step 204 extending from the center toward the outer periphery is provided on the bottom portion 202 of the outer tub 20, and the inner surface of the bottom portion 202 slopes downward from the right side of the step 204 in the direction of the dashed arrow in Fig. 2. On the left side of the step 204, where the inner surface of the bottom portion 202 is lowest, a drain recess 205 is formed by recessing the bottom portion 202, and a drain port 203 is provided within the drain recess 205. The inner surface of the bottom portion 202 of the outer tub 20 slopes downward from the center toward the outer periphery.

[0036] A cylindrical mounting hole 206 that protrudes slightly downward is formed in the bottom surface portion 202 of the outer tub 20 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 surface portion 202. An electrode-type conductivity sensor is attached to the mounting hole 206 from below as the water level detection unit 60.

[0037] The water level detection unit 60 has a cylindrical shape with an upper part 60a having a smaller outer diameter than the lower part 60b, and the upper part 60a is fitted into the mounting port 206. A packing 210 is provided between the lower part 60b and the mounting port 206 to provide a water seal. The tip of the upper part 60a protrudes above the inner surface of the bottom part 202, and has a groove part 61 in the center. The bottom surface of the groove part 61 is lower than the inner surface of the bottom part 202 around the mounting port 206, and the part of the groove part 61 lower than the inner surface of the bottom part 202 becomes a residual water pocket 207 recessed from the inner surface of the bottom part 202.

[0038] In the water level detection unit 60, a pair of electrodes 62 are provided on two opposing side wall surfaces of the groove portion 61. The pair of electrodes 62 have a rectangular plate shape and are disposed in the space between the bottom portion 202 and the bottom portion 22b of the washing and dewatering tub 22 so as to protrude upward from the bottom surface of the residual water pocket 207 in the bottom portion 202.

[0039] The water level detection unit 60 is used to detect the water level in the outer tub 20 in the control process in the final spin-drying step, which will be described later.

[0040] When detecting the water level in the outer tub 20, the water level detection unit 60 applies a voltage to the pair of electrodes 62. When water is present between the pair of electrodes 62, a current flows between the electrodes with a magnitude corresponding to the conductivity between the electrodes. That is, as the water level in the outer tub 20 rises and the water level between the pair of electrodes 62 increases, the surface area of ​​the electrode 62 in contact with the water increases, so that the conductivity between the electrodes increases and the current flowing between the electrodes increases.

[0041] The water level detection unit 60 detects the water level between a pair of electrodes 62, i.e., the conductivity that changes depending on the water level in the outer tank 20, as a current value, and outputs a detection signal indicating the detected conductivity to the control unit 101.

[0042] The water level detection unit 60 can detect the water level in the outer tub 20 from the bottom surface of the residual water pocket 207, where the lower ends of the pair of electrodes 62 are located, to the position of the upper ends of the pair of electrodes 62. In other words, the position of the upper ends of the pair of electrodes 62 is the upper limit water level that can be detected by the water level detection unit 60. When the water level in the outer tub 20 exceeds the upper limit water level, the conductivity detected by the water level detection unit 60 no longer changes.

[0043] FIG. 3 is a block diagram showing the configuration of the fully automatic washing machine 1. As shown in FIG.

[0044] In addition to the above-mentioned configuration, the fully automatic washing machine 1 includes a control unit 100. The control unit 100 includes a control unit 101, a memory unit 102, a motor drive unit 103, a clutch drive unit 104, a water supply valve drive unit 105, and a drain valve drive unit 106. The fully automatic washing machine 1 also includes an operation unit 110 and a water level sensor 120.

[0045] The operation unit 110 includes various operation buttons such as a power button for turning on and off the power to the fully-automatic washing machine 1, a start / pause button for starting and pausing a washing operation, a course selection button for selecting an arbitrary operation course from a plurality of operation courses related to the washing operation, etc. The operation unit 110 outputs an input signal to the control unit 101 according to the operation button operated by the user.

[0046] Water level sensor 120 is a diaphragm type water level sensor, and is connected via a hose to an air trap provided at the bottom of outer tub 20. Water level sensor 120 detects the air pressure in the air trap to detect the water level in washing and spin-drying tub 22, i.e., in outer tub 20, and outputs a water level signal to control unit 101 according to the detected water level.

[0047] The motor driving unit 103 drives the driving motor 31 in accordance with a control signal output from the control unit 101. The motor driving unit 103 includes a rotation sensor that detects the rotation speed of the driving motor 31, an inverter circuit, etc., and adjusts the driving power so that the driving motor 31 rotates at the rotation speed set by the control unit 101. Furthermore, the motor driving unit 103 includes a current detection circuit that detects the current flowing through the driving motor 31.

[0048] The clutch driving unit 104 drives the clutch mechanism 32a of the transmission mechanism unit 32 in accordance with a control signal output from the control unit 101. The water supply valve driving unit 105 drives the water supply valve 51 in accordance with a control signal from the control unit 101. The drain valve driving unit 106 drives the drain valve 41 in accordance with a control signal from the control unit 101.

[0049] The storage unit 102 includes an EEPROM, a RAM, etc. The storage unit 102 stores programs for executing various operation courses of the washing operation. The storage unit 102 also stores various operation conditions used for the washing operation.

[0050] The control unit 101 includes a CPU and the like, and controls the motor driving unit 103, the clutch driving unit 104, the water supply valve driving unit 105, the drain valve driving unit 106, and the like in accordance with a program stored in the storage unit .

[0051] The fully automatic washing machine 1 performs various washing operations of various operation courses. When the washing operation is performed, laundry is placed in the washing and dewatering tub 22 by the user.

[0052] FIG. 4 is a flowchart showing the flow of the washing operation.

[0053] In the washing operation, a load amount detection step, a washing step, an intermediate spin-drying step, a rinsing step, and a final spin-drying step are executed in order (S1 to S5). Depending on the operation course, the intermediate spin-drying step (S3) and the rinsing step (S4) are executed multiple times.

[0054] In the load amount detection step (S1), the control unit 101 operates the drive motor 31 to rotate the pulsator 24, and determines the load amount based on the drive current of the drive motor 31 and the amount of inertial rotation until the drive motor 31 stops. The greater the load amount, the greater the drive current and the smaller the amount of inertial rotation. The control unit 101 sets the amount of water to be supplied in the washing process and the rinsing process (washing water level, rinsing water level) and the amount of detergent to be dispensed in the washing process according to the detected load amount. The greater the load amount, the greater the amount of water to be supplied and the amount of detergent to be dispensed. The amount of water to be supplied and the amount of detergent to be dispensed are displayed on a display unit not shown. The control unit 101 stores the detected load amount in the memory unit 102.

[0055] The pulsator 24, the drive motor 31 and the control unit 101 constitute the "load amount detection unit" of the present invention.

[0056] In the washing step (S2), the control unit 101 controls the water supply unit 50 to supply water into the outer tub 20 up to the washing water level set based on the load amount. When supplying water, an amount of detergent set based on the load amount is added. This causes water containing detergent to accumulate in the outer tub 20. Next, the control unit 101 controls the drive motor 31 to rotate the pulsator 24 alternately clockwise and counterclockwise. A water flow is generated in the washing and spin-drying tub 22, and the laundry is washed by the force of the water flow and detergent. After a predetermined washing time has elapsed, the control unit 101 opens the drain valve 41 to drain water from the outer tub 20. In this way, the washing step ends. The drain valve 41 remains open.

[0057] In the intermediate spin-drying step (S3), when no water is stored in outer tub 20, control unit 101 operates drive motor 31 to rotate washing / spinning tub 22 together with pulsator 24 at high speed at a predetermined spin-drying rotation speed. The laundry is spin-dried by the action of centrifugal force generated in washing / spinning tub 22. When a predetermined spin-drying time has elapsed since the rotation speed of washing / spinning tub 22 reaches the spin-drying rotation speed, control unit 101 stops drive motor 31 to stop washing / spinning tub 22. Furthermore, control unit 101 closes drain valve 41. In this way, the intermediate spin-drying step ends.

[0058] In the rinsing step (S4), the control unit 101 controls the water supply unit 50 to supply water into the outer tub 20 up to the rinsing water level set based on the load amount. This allows water to accumulate in the outer tub 20. Next, the control unit 101 controls the drive motor 31 to rotate the pulsator 24 alternately clockwise and counterclockwise. A water flow is generated in the washing and spin-drying tub 22, and the laundry is rinsed by the force of the generated water flow. After a predetermined rinsing time has elapsed, the control unit 101 opens the drain valve 41 to drain water from the outer tub 20. In this way, the rinsing step ends. The drain valve 41 remains open.

[0059] The control unit 101 measures the drainage capacity of the drain unit 40 when draining water from the outer tub 20 in the rinsing process. That is, the control unit 101 measures the drainage time required for the water level in the outer tub 20 to drop by a predetermined amount. The shorter the drainage time, the higher the drainage capacity can be considered to be. The control unit 101 stores the measured drainage time in the memory unit 102 as information indicating the drainage capacity. The drainage capacity is used in the spin-drying operation condition determination process executed by the control unit 101 in the final spin-drying process.

[0060] In the final spin-drying step (S5), similarly to the intermediate spin-drying step, the control unit 101 operates the drive motor 31 to rotate the washing / spin-drying tub 22 together with the pulsator 24 at high speed at the spin-drying rotation speed. The laundry is spin-dried by the action of the centrifugal force generated in the washing / spin-drying tub 22. When the spin-drying time has elapsed after the rotation speed of the washing / spin-drying tub 22 reaches the spin-drying rotation speed, the control unit 101 stops the washing / spin-drying tub 22 and closes the drain valve 41. In this manner, the final spin-drying step ends, and the washing operation ends.

[0061] The intermediate dehydration process and the final dehydration process are both dehydration processes, and hereinafter, when there is no need to distinguish between them, they will simply be referred to as dehydration processes.

[0062] FIG. 5 is a flowchart showing the spin-drying control process executed by control unit 101 in the spin-drying step.

[0063] 5, when the spin-drying process is started, control unit 101 sets the target rotation speed of washing / spin-drying tub 22 to a first rotation speed, starts drive motor 31, and starts washing / spin-drying tub 22 (S101). The first rotation speed is set to a rotation speed slightly higher than the rotation speed (e.g., 50 to 60 rpm) at which washing / spin-drying tub 22 and outer tub 20 greatly vibrate in the horizontal direction due to resonance, i.e., 120 rpm.

[0064] When the rotation speed of washing / drying tub 22 reaches the first rotation speed (S102: YES), control unit 101 maintains the rotation speed of washing / drying tub 22 at the first rotation speed (S103) and waits for a first time to elapse from the start of maintaining the rotation speed (S104). The first time is a period of several tens of seconds, for example 30 seconds, and is set before the spin-drying process depending on the load of laundry in washing / drying tub 22, etc. During the first time, most of the amount of water that can be discharged can be squeezed out of the laundry by centrifugal force acting at the first rotation speed.

[0065] When the first time period has elapsed (S104: YES), the control unit 101 sets the target rotation speed to the second rotation speed, and increases the rotation speed of the washing and spin-drying tub 22 (S105). The second rotation speed is set to a rotation speed that is slightly higher than the rotation speed at the so-called vertical resonance point (e.g., 200 to 220 rpm) at which the washing and spin-drying tub 22 and the outer tub 20 greatly vibrate in the vertical direction due to resonance, and is set to, for example, 240 rpm.

[0066] When the rotation speed of washing / drying tub 22 reaches the second rotation speed (S106: YES), control unit 101 maintains the rotation speed of washing / drying tub 22 at the second rotation speed (S107) and waits for the second time to elapse from the start of maintaining the rotation speed (S104). The second time is a period of several tens of seconds to about one minute, for example 50 seconds, which is longer than the first time, and is set before the spin-drying step depending on the load of laundry in washing / drying tub 22, etc. During the second time, most of the amount of water that can be discharged can be discharged from the laundry by centrifugal force acting at the second rotation speed.

[0067] When the second time period has elapsed (S108: YES), control unit 101 sets the target rotation speed to the dehydration rotation speed, and increases the rotation speed of washing / dehydrating tub 22 (S109).

[0068] In the intermediate spin-drying step, the spin-drying speed is set to a predetermined speed (e.g., 700 rpm). In the final spin-drying step, the spin-drying speed is set to a speed determined according to the fabric quality of the laundry in the washing and spin-drying tub 22 by a spin-drying operation condition determination process described later.

[0069] As the second time period approaches the end, the amount of water drained from the laundry decreases, but as the rotation speed of the washing and spin-drying tub 22 increases from the second rotation speed, the centrifugal force acting on the laundry increases, and more water may be drained from the laundry than at the second rotation speed.

[0070] When the rotation speed of the washing / spinning tub 22 reaches the spin rotation speed (S110: YES), the control unit 101 maintains the rotation speed of the washing / spinning tub 22 at the spin rotation speed (S111) and waits for the spin time to elapse from the start of the maintenance (S112). The spin time may be several minutes to several tens of minutes. In the final spin-drying step, the spin-drying time is set to a time determined according to the fabric quality of the laundry in the washing / spin-drying tub 22 by a spin-drying operation condition determination process described later.

[0071] When the spin-drying time has elapsed (S112: YES), control unit 101 stops drive motor 31 and stops washing / drying tub 22 (S113), thus completing the spin-drying process.

[0072] In addition, the dehydration time does not have to be the time from when the rotation speed of the washing and dehydrating tub 22 reaches the dehydration rotation speed to when the washing and dehydrating tub 22 is stopped, but may be the time from when the rotation of the washing and dehydrating tub 22 starts to when it is stopped.

[0073] In the final spin-drying step, the control unit 101 executes a spin-drying operation condition determination process in parallel with the spin-drying control process of Fig. 5. In the spin-drying operation condition determination process, during the period when the rotation of the washing and spin-drying tub 22 starts up in the final spin-drying step, the fabric quality of the laundry in the washing and spin-drying tub 22 is determined based on the water level in the outer tub 20, which changes according to the amount of liquid removed from the laundry per unit time. Then, the spin-drying operation conditions, that is, the spin-drying time and the spin-drying rotation speed, are set to values ​​according to the determined fabric quality.

[0074] Fig. 6 is a flowchart showing the dehydration operation condition determination process executed by the control unit 101 in the final dehydration step. Fig. 7 is a flowchart showing the reference conductivity acquisition process included in the dehydration operation condition determination process. Fig. 8 is a flowchart showing the judged conductivity acquisition process included in the dehydration operation condition determination process.

[0075] 6, control unit 101 closes drain valve 41 (S201). The timing for closing drain valve 41 is set to be simultaneous with, immediately before, or immediately after the start of washing / dehydrating tub 22. When drain valve 41 is closed, the dehydrated liquid discharged from the laundry by the rotation of washing / dehydrating tub 22 accumulates at the bottom of outer tub 20.

[0076] Next, the control unit 101 executes a reference conductivity acquisition process (S202).

[0077] Referring to FIG. 7, the control unit 101 detects the conductivity by the water level detection unit 60 at a fixed sampling time interval, for example, at intervals of 0.1 seconds, and monitors whether the rate of change of the conductivity has reached or fallen below a specified value by comparing the conductivity measured previously with the conductivity measured this time (S301 to S303).

[0078] The pair of electrodes 62 of the water level detection unit 60 are arranged to protrude upward from the inner bottom surface of the outer tank 20, and are gradually submerged as the excreted liquid accumulates. Until the pair of electrodes 62 are completely submerged, the surface area of ​​the electrodes 62 that comes into contact with the excreted liquid changes due to the rise in the water level, and therefore the conductivity between the electrodes changes.

[0079] When the pair of electrodes 62 are completely submerged, the detected change in conductivity disappears, and the rate of change reaches or falls below the specified value. When the control unit 101 determines that the rate of change in conductivity has reached or falls below the specified value (S302: YES), it determines the currently measured conductivity, i.e., the conductivity immediately after it reaches or falls below the specified value, as the reference conductivity (S304). The reference conductivity is the conductivity when the drainage water level in the outer tank 20 is the upper limit water level that the water level detection unit 60 can detect.

[0080] It is also possible to measure the conductivity multiple times after it becomes equal to or lower than the specified value, and to determine the average value of the multiple conductivities as the reference conductivity.

[0081] When the reference conductivity is thus acquired, the reference conductivity acquisition process ends.

[0082] Returning to FIG. 6, when the reference conductivity acquisition process is completed, the control unit 101 opens the drain valve 41 (S203). When the drain valve 41 is opened, the water level of the deliquescence in the outer tub 20 is close to the upper limit water level that can be detected by the water level detection unit 60. When the drain valve 41 is opened, the drainage of the deliquescence in the outer tub 20 starts while deliquescence from the laundry continues. Thereafter, the water level in the outer tub 20 changes according to the amount of deliquescence per unit time from the laundry, and the greater the amount of deliquescence per unit time, the slower the drop in the water level in the outer tub 20 becomes.

[0083] Next, the control unit 101 executes a determined conductivity acquisition process (S204).

[0084] Referring to FIG. 8, the control unit 101 causes the water level detection unit 60 to detect the conductivity at a constant sampling time interval, for example, 0.1 second, until a predetermined number of conductivities, for example, 100, are detected (S401 to S403).

[0085] When a predetermined number of conductivities are detected (S402: YES), the control unit 101 calculates an average value of these conductivities and sets the average value as a determined conductivity (S404).

[0086] The determined conductivity indicates an average water level obtained by averaging a predetermined number of water levels detected each time a sampling time has elapsed since the drain valve 41 was opened, and this average water level is a value corresponding to the amount of liquid removed per unit time. Therefore, the determined conductivity is a conductivity corresponding to the water level corresponding to the amount of liquid removed per unit time, detected by the water level detection unit 60 after the reference conductivity is determined and the drain valve 41 is opened. The determined conductivity, i.e., the value of the average water level, increases as the amount of liquid removed per unit time increases.

[0087] When the determined conductivity is thus acquired, the process of acquiring the determined conductivity ends.

[0088] Returning to FIG. 6, the control unit 101 obtains a determination water level value by dividing the determination conductivity by the reference conductivity (S205).

[0089] Even if the water level in the outer tub 20 is the same, the conductivity detected by the water level detection unit 60 may be different due to differences in the conductivity of the drained water itself. The conductivity of the drained water itself may change depending on the properties of the tap water from which the drained water is discharged and the detergent concentration during draining.

[0090] In this embodiment, the judgment water level value is expressed as the ratio of the average water level during deliquing, which changes according to the amount of deliquing per unit time, to the upper limit water level during the same deliquing that can be detected by the water level detection unit 60. Therefore, the judgment water level value is an accurate value that is not affected by the conductivity of the deliquing itself.

[0091] If the laundry is significantly unevenly distributed in the washing / drying tub 22, the outer tub 20 tends to vibrate when the washing / drying tub 22 starts to rotate, causing the water in the outer tub 20 to vibrate and making it easier for the water level between the pair of electrodes 62 to increase or decrease. Therefore, if a judgment water level value is determined from only one water level detected at a timing when a predetermined time has elapsed since the drain valve 41 was opened, it will be significantly affected by the increase or decrease in the water level, making it difficult to accurately obtain the judgment water level value.

[0092] In this embodiment, the judgment water level value is determined from the average value of a predetermined number of water levels detected after the drain valve 41 is opened, making it less susceptible to the effects of increases and decreases in water level and making it easier to obtain the judgment water level value with high accuracy.

[0093] When the determination water level value is thus obtained, the control unit 101 determines the fabric type of the laundry in the washing and spin-drying tub 22 by comparing the determination water level value with a predetermined threshold value.

[0094] If the laundry contains a lot of clothes made of fabrics that easily absorb water, such as cotton, the amount of liquid removed per unit time increases, so the water level in the outer tub 20 drops more slowly after drainage starts. This increases the critical conductivity, and therefore the critical water level value.

[0095] On the other hand, if the laundry contains a lot of clothes made of fabrics that are difficult to absorb water, such as chemical fibers, the amount of liquid removed per unit time decreases, and the water level in the outer tub 20 drops quickly. This reduces the critical conductivity, and therefore the critical water level value.

[0096] However, the amount of liquid removed per unit time is also affected by the laundry load, and the larger the load, the larger the amount of liquid removed per unit time. Furthermore, the speed at which the water level in the outer tub 20 drops is also affected by the drainage capacity of the drain section, and the lower the drainage capacity, the slower the water level drops in the outer tub 20. Therefore, the threshold value for determining the fabric type needs to be changed depending on the load and the drainage capacity.

[0097] 3, a threshold determination table 102a used to determine a threshold value according to the laundry load and the drainage capacity is stored in the storage unit 102. An example of the threshold determination table 102a is shown in FIG.

[0098] In the threshold determination table 102a, each threshold value Xn used for determining the fabric quality is registered in association with the load amount and the drainage capacity. The threshold value Xn is increased as the load amount increases and increased as the drainage capacity decreases.

[0099] In the threshold determination table 102a shown in FIG. 9, the load amount is divided into three ranges and the drainage capacity is divided into two ranges, but the load amount may be divided into two or four or more ranges, and the drainage capacity may be divided into three or more ranges.

[0100] The control unit 101 reads out from the storage unit 102 the laundry load amount and the drain time stored in the storage unit 102 as information indicating the drain capacity, and determines the threshold value Xn according to the load amount and the drain capacity with reference to the threshold value determination table 102a (S206). Then, the control unit 101 determines whether the determination water level value is greater than the threshold value (S207).

[0101] When the laundry in the washing and drying tub 22 contains a large amount of clothes that easily absorb water (such as cotton), the judgment water level value becomes greater than the threshold value, and when the laundry contains a large amount of clothes that do not easily absorb water (such as synthetic fibers), the judgment water level value becomes less than the threshold value.

[0102] If the control unit 101 determines that the judgment water level value is greater than the threshold value (S207: YES), it sets the spin-drying rotation speed to a third rotation speed (e.g., 800 rpm) (S208) and sets the spin-drying time to a third time (e.g., 5 minutes) (S209).

[0103] On the other hand, if the control unit 101 determines that the judgment water level value is equal to or lower than the threshold value (S207: NO), it sets the spin-drying rotation speed to a fourth rotation speed (e.g., 700 rpm) lower than the third rotation speed (S210), and sets the spin-drying time to a fourth time (e.g., 4 minutes) shorter than the third time (S211).

[0104] In this way, the spin-drying operation condition determination process is completed. The spin-drying operation condition determination process is completed during the period from when washing / dehydrating tub 22 starts to rotate until the rotation speed of washing / dehydrating tub 22 increases from the second rotation speed.

[0105] In this manner, in the present embodiment, in the final spin-drying step, when the laundry in the washing / spin-drying tub 22 contains many clothes that easily absorb water, the washing / spin-drying tub 22 rotates at a relatively high spin-drying speed for a long spin-drying time, preventing the laundry from becoming insufficiently spin-dry. Furthermore, when the laundry in the washing / spin-drying tub 22 contains many clothes that do not easily absorb water, the washing / spin-drying tub 22 rotates at a relatively low spin-drying speed for a short spin-drying time, preventing the laundry from becoming over-spin-dry.

[0106] <Effects of the embodiment> According to this embodiment, the fully automatic washing machine 1 is equipped with a water level detection unit 60 that detects the water level in the outer tub 20, and the control unit 101 determines the fabric quality of the laundry in the washing and dehydrating tub 22 based on the water level in the outer tub 20, which changes depending on the amount of liquid removed from the laundry per unit time, during the period when the rotation of the washing and dehydrating tub 22 starts up in the final dehydration process, and sets the dehydration time and dehydration rotation speed to values ​​according to the determined fabric quality.

[0107] According to this configuration, when the laundry in the washing / spinning tub 22 contains a large amount of clothes made of fabric that easily absorbs water, the spin-drying time can be relatively long and the spin-drying rotation speed can be relatively high, so that the laundry is less likely to be insufficiently spin-dried. Furthermore, when the laundry in the washing / spinning tub 22 contains a large amount of clothes made of fabric that does not easily absorb water, the spin-drying time can be relatively short and the spin-drying rotation speed can be relatively low, so that the laundry is less likely to be over-spin-dried. Therefore, it is possible to finish the laundry in an appropriate spin-drying state regardless of the state of its fabric.

[0108] Furthermore, according to this embodiment, the water level detection unit 60 has a pair of electrodes 62 arranged on the bottom surface 202 of the outer tub 20, and detects the electrical conductivity between the electrodes, which changes according to the water level in the outer tub 20. Then, the control unit 101 determines the fabric type based on the electrical conductivity detected by the water level detection unit 60.

[0109] According to this configuration, the water level detector 60 can detect the water level in the outer tub 20, which changes according to the amount of drainage per unit time, by the conductivity generated between the electrodes.

[0110] Furthermore, according to this embodiment, the control unit 101 closes the drain valve 41 to store the liquid removed from the laundry in the outer tub 20 to completely submerge the pair of electrodes 62, and sets the conductivity detected by the water level detection unit 60 after the pair of electrodes 62 are completely submerged as the reference conductivity. Furthermore, the control unit 101 opens the drain valve 41 after the pair of electrodes 62 are completely submerged, and sets the conductivity corresponding to the water level according to the amount of liquid removed per unit time, detected by the water level detection unit 60 after the drain valve 41 is opened, as the judgment conductivity. Then, the control unit 101 compares a judgment water level value obtained by dividing the judgment conductivity by the reference conductivity with a predetermined threshold value to judge the fabric quality, and when the judgment water level value is greater than the threshold value, makes the spin-drying time longer and increases the spin-drying rotation speed compared to when the judgment water level value is equal to or less than the threshold value.

[0111] According to this configuration, the water level judgment value is expressed as the ratio of the water level of the dehydration, which changes according to the amount of dehydration per unit time, to the upper limit water level that the water level detection unit 60 can detect for the same dehydration, so it is not affected by the conductivity of the dehydration itself and is likely to be an accurate value. Therefore, by comparing the water level judgment value with a threshold value, the fabric quality can be judged with high accuracy and the dehydration time and dehydration rotation speed can be adjusted. This makes it possible to finish the laundry in an even more suitable dehydration state.

[0112] Furthermore, according to this embodiment, the control unit 101 measures the drainage capacity when draining water from the outer tub 20 before the final spin-drying step, and sets the threshold value to a larger value as the drainage capacity decreases.

[0113] According to this configuration, even if the drainage capacity from within the outer tub 20 affects the change in the water level within the outer tub 20, the threshold value is changed according to the drainage capacity, so that the fabric quality can be determined with high accuracy.

[0114] Furthermore, according to this embodiment, the control unit 101 sets the threshold value to a larger value as the load amount increases.

[0115] According to this configuration, even if the laundry load affects the amount of liquid removed per unit time, the threshold value is changed according to the load, so that the fabric quality can be determined with high accuracy.

[0116] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications of the embodiment of the present invention are possible.

[0117] <Change Example 1> In the above embodiment, in order to detect the water level in the outer tub 20, which changes according to the amount of liquid removed from the laundry per unit time, without being affected by the conductivity of the deliquescence itself, a judgment water level value obtained by dividing the judgment conductivity by the reference conductivity is used. Then, so that the reference conductivity and the judgment conductivity are the conductivity of the same deliquescence, that is, the conductivity of water of exactly the same quality, the conductivity when the pair of electrodes 62 are completely submerged in water due to deliquescence is obtained as the reference conductivity, and the conductivity when water is drained from the outer tub 20 from a state in which the pair of electrodes 62 are completely submerged in water is obtained as the judgment conductivity.

[0118] The water in the outer tub 20 immediately before or during drainage in the rinsing step before the final spin-drying step contains approximately the same amount of detergent as the water drained from the laundry, and has approximately the same quality and electrical conductivity.

[0119] Therefore, in this modified example, the conductivity when the pair of electrodes 62 is completely submerged in the water in the outer tub 20 immediately before or during drainage in the rinsing process is obtained as the reference conductivity. Then, in the final spin-drying process, rotation of the washing and spin-drying tub 22 is started with the drain valve 41 closed, and the conductivity when the water level in the outer tub 20 rises according to the amount of liquid drained from the laundry per unit time is obtained as the determined conductivity.

[0120] Fig. 10(a) is a flowchart showing a spin-drying operation condition determination process executed by the control unit 101 in the final spin-drying step according to Modification 1. Fig. 10(b) is a diagram showing an example of a threshold determination table 102b according to Modification 1.

[0121] 10(a), the control unit 101 closes the drain valve 41 (S501). The timing for closing the drain valve 41 is set to be simultaneous with, immediately before, or immediately after the start of the washing and spin-drying tub 22. When the drain valve 41 is closed, the liquid drained from the laundry by the rotation of the washing and spin-drying tub 22 accumulates at the bottom of the outer tub 20, and the water level in the outer tub 20 rises.

[0122] Next, the control unit 101 executes the determined conductivity acquisition process of Fig. 8 and acquires the determined conductivity (S502). The determined conductivity indicates an average water level obtained by averaging a predetermined number of water levels detected each time a sampling time has elapsed since the drain valve 41 was closed, and the average water level is a value corresponding to the amount of drainage per unit time. Therefore, the determined conductivity is a conductivity corresponding to the water level detected by the water level detection unit 60 after the drain valve 41 was closed and corresponding to the amount of drainage per unit time. The determined conductivity, i.e., the value of the average water level, increases as the amount of drainage per unit time increases.

[0123] When the control unit 101 acquires the determined conductivity, it opens the drain valve 41 (S503). This allows the liquid removed from the laundry to be discharged from the outer tub 20.

[0124] Next, the control unit 101 obtains a determination water level value by dividing the determination conductivity by the reference conductivity (S504).

[0125] The reference conductivity is obtained in the rinsing step performed before the final spin-drying step. That is, the control unit 101 detects the conductivity with the water level detection unit 60 in a state in which the pair of electrodes 62 are completely submerged in the water in the outer tub 20 immediately before or during drainage in the rinsing step (S4), and sets the detected conductivity as the reference conductivity.

[0126] In this modified example, the judgment water level value is expressed as the ratio of the average water level of the deliquor, which changes according to the amount of deliquor per unit time, to the upper limit water level of the post-rinsing water of the same quality as the deliquor that can be detected by the water level detection unit 60. Therefore, the judgment water level value is an accurate value that is not easily affected by the conductivity of the deliquor itself.

[0127] In this modification, a threshold determination table 102b is stored in the storage unit 102 instead of the threshold determination table 102a in the above embodiment. As shown in Fig. 10(b), the threshold determination table 102b registers each threshold value Yn used for determining the fabric quality in association with the laundry load. The threshold value Yn is increased as the load increases.

[0128] In the threshold determination table 102b shown in FIG. 10(b), the load amount is divided into three ranges, but the load amount may be divided into two or four or more ranges.

[0129] The control unit 101 reads out the load amount of the laundry from the storage unit 102, and determines the threshold value Yn according to the load amount by referring to the threshold value determination table 102b (S505). Then, the control unit 101 determines whether the determination water level value is greater than the threshold value (S506).

[0130] If the control unit 101 determines that the judgment water level value is greater than the threshold value (S506: YES), it sets the spin-drying rotation speed to a third rotation speed (e.g., 800 rpm) (S507) and sets the spin-drying time to a third time (e.g., 5 minutes) (S508).

[0131] On the other hand, if the control unit 101 determines that the judgment water level value is equal to or lower than the threshold value (S506: NO), it sets the spin-drying rotation speed to a fourth rotation speed (e.g., 700 rpm) lower than the third rotation speed (S509), and sets the spin-drying time to a fourth time (e.g., 4 minutes) shorter than the third time (S510).

[0132] Thus, the dehydration operation condition determination process is completed.

[0133] According to this modification, the water level judgment value is expressed as a ratio of the water level of the deliquor, which changes according to the amount of deliquor per unit time, to the upper limit water level that the water level detection unit 60 can detect using water after rinsing of the same quality as the deliquor, so it is less affected by the conductivity of the deliquor itself and is likely to be an accurate value. Therefore, by comparing the water level judgment value with a threshold value, the fabric quality can be judged with high accuracy and the dehydration time and dehydration rotation speed can be adjusted. This makes it possible to finish the laundry in an even more suitable dehydration state.

[0134] Furthermore, according to this modification, even if the laundry load affects the amount of liquid removed per unit time, the threshold value is changed according to the load, so that the fabric quality can be determined with high accuracy.

[0135] <Other changes> In the above embodiment and modified example 1, in the determined conductivity acquisition process of Fig. 8, the control unit 101 detects a predetermined number of conductivities using the water level detection unit 60 and sets the average value of these conductivities as the determined conductivity. However, the control unit 101 may detect a conductivity using the water level detection unit 60 at the start of the determined conductivity acquisition process, that is, at the timing when a predetermined time (for example, 10 seconds) has elapsed since the drain valve 41 was opened in the above embodiment or since the drain valve 41 was closed in modified example 1, and set this one conductivity as the determined conductivity.

[0136] Furthermore, in the above embodiment and modified example 1, the control unit 101 sets both the spin-drying time and the spin-drying rotation speed in the final spin-drying step to values ​​corresponding to the determined fabric quality. However, the control unit 101 may set only one of the spin-drying time and the spin-drying rotation speed in the final spin-drying step to a value corresponding to the determined fabric quality.

[0137] Furthermore, in the above embodiment, a residual water pocket 207 is provided on the bottom surface 202 of the outer tub 20, and a pair of electrodes 62 of the water level detection unit 60 protrude upward from the bottom surface of the residual water pocket 207. However, a configuration in which the residual water pocket 207 is not provided on the bottom surface 202 of the outer tub 20 may be adopted. In this case, it is preferable to adopt a configuration in which the pair of electrodes 62 of the water level detection unit 60 protrude upward from the inner surface of the bottom surface 202.

[0138] Furthermore, in the above embodiment, the water level detection unit 60 is a conductivity sensor that detects the conductivity between a pair of electrodes 62 that changes in response to changes in the water level in the outer tub 20. However, the water level detection unit 60 may have any configuration as long as it can detect the water level in the outer tub 20.

[0139] Furthermore, in the above embodiment, an example in which the present invention is applied to a fully automatic washing machine 1 has been 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 drum-type washer-dryer that have a horizontal shaft-type drum as an inner tub inside an outer tub.

[0140] In addition, the embodiments of the present invention can be modified in various ways as appropriate within the scope of the technical ideas set forth in the claims. [Explanation of symbols]

[0141] 1. Fully automatic washing machine (washing machine) 10. Chassis 20 Outer tank 22 Washing and spinning tub (inner tub) 24 Pulsator (load detector) 31 Drive motor (load detection unit) 41 Drain valve 60 Water level detector 62 electrodes 101 Control unit (load amount detection unit) 202 Bottom part 203 Drain port

Claims

1. an outer tank disposed within the housing and configured to store water; an inner tub that is rotatably disposed within the outer tub and that accommodates laundry; A drive motor that drives the inner tank; a control unit that controls the drive motor to execute a spin-drying process in which the inner tub is rotated for a predetermined spin-drying time and at a predetermined spin-drying rotation speed; A water level detection unit that detects the water level in the outer tank, The control unit is determining a fabric quality of the laundry in the inner tub based on a water level in the outer tub that changes according to an amount of liquid removed from the laundry per unit time during a period when the rotation of the inner tub is increasing in a final spin-drying step; The dewatering time and / or the dewatering rotation speed are set to a value according to the determined fabric quality. A washing machine characterized by:

2. The washing machine according to claim 1, the water level detector has a pair of electrodes disposed on a bottom surface of the outer tub and detects electrical conductivity between the electrodes that changes in response to the water level in the outer tub; The control unit determines the fabric type based on the electrical conductivity detected by the water level detection unit. A washing machine characterized by:

3. The washing machine according to claim 2, A drain port provided on a bottom surface of the outer tank; A drain valve that opens and closes the drain outlet portion, The control unit is The drain valve is closed to collect the liquid drained from the laundry in the outer tub, thereby completely submerging the pair of electrodes in water, and the conductivity detected by the water level detection unit after the pair of electrodes is completely submerged in water is set as a reference conductivity. After the pair of electrodes is completely submerged in water, the drain valve is opened, and the conductivity corresponding to the water level according to the amount of drainage per unit time detected by the water level detection unit after the drain valve is opened is set as a determined conductivity; A determination water level value obtained by dividing the determination conductivity by the reference conductivity is compared with a predetermined threshold value to determine the fabric quality; When the judgment water level value is greater than the threshold value, the spin-drying time is made longer and / or the spin-drying rotation speed is made higher than when the judgment water level value is equal to or less than the threshold value. A washing machine characterized by:

4. The washing machine according to claim 3, The control unit measures a drainage capacity during drainage from the outer tub before the final spin-drying step, and sets the threshold value to a larger value as the drainage capacity decreases. A washing machine characterized by:

5. The washing machine according to claim 2, A drain port provided on a bottom surface of the outer tank; A drain valve that opens and closes the drain outlet portion, The control unit is Immediately before or during drainage in a rinsing step carried out before the final dewatering step, The conductivity is detected by the water level detector in a state where the pair of electrodes are completely submerged in the water in the outer tank, and the detected conductivity is set as a reference conductivity. In the final dehydration step, the drain valve is closed and the rotation of the inner tank is started, and the conductivity corresponding to the water level according to the amount of drainage per unit time detected by the water level detection unit after the drain valve is closed is set as a determined conductivity; A determination water level value obtained by dividing the determination conductivity by the reference conductivity is compared with a predetermined threshold value to determine the fabric quality; When the judgment water level value is greater than the threshold value, the spin-drying time is made longer and / or the spin-drying rotation speed is made higher than when the judgment water level value is equal to or less than the threshold value. A washing machine characterized by:

6. The washing machine according to any one of claims 3 to 5, The washing machine further includes a load amount detection unit that detects a load amount of laundry contained in the inner tub, The control unit sets the threshold value to a larger value as the load amount increases. A washing machine characterized by:

Images