Patent ID: 12252832

DETAILED DESCRIPTION

FIG.1is a diagram illustrating an exemplary washing machine, andFIG.2is a diagram illustrating a control relationship between components included in the exemplary washing machine.

Referring toFIGS.1and2, a washing machine100can include an outer tub3containing water, and an inner tub4that accommodates laundry and is rotatably disposed in the outer tub3, and a pulsator5that is rotatably disposed at a lower portion of the inner tub4.

The outer tub3is disposed in a casing defining the exterior of the washing machine100, and can be suspended within the casing by a suspension so that the vibration caused by the rotation of the inner tub4can be buffered.

The outer tub3rotates about an axis perpendicular to the ground, and the outer tub3can have a tubular shape with an opening defined at an upper side so that laundry can be received by the inner tub4from the upper side.

The inner tub4can be rotatably disposed in the outer tub3, and an opening providing fluid communication to the outer tub3can be defined at a lower portion of the inner tub4.

A plurality of through holes providing fluid communication to the outer tub3is defined at a side surface (on an inner circumferential surface) of the inner tub4to allow moisture to be introduced and emitted.

In addition, a nozzle43configured to inject water into the inner tub4by using centrifugal force according to the rotation of the inner tub4can be provided.

A plurality of through holes can be defined in the pulsator5, and the water introduced from the outer tub3through the opening of the inner tub4can move upward through the through holes defined at the pulsator5to move into the inner tub4.

A motor6can provide a rotational force to the inner tub4or the pulsator5. The rotational shaft of the motor6can be coupled to the pulsator5to provide the rotational force, and the rotational shaft of the motor6can provide the rotational force to the inner tub4through clutch engagement. Therefore, in the state in which the clutch is engaged, the rotation shaft rotates integrally with the inner tub4and the pulsator5. In some implementations, when the clutch is released, the inner tub4, in a stopped state, can rotate only the pulsator5.

The motor6can be capable of speed control. For example, the motor6can be a brushless DC motor (BLDC), but is not necessarily limited thereto. A technology for controlling the rotation speed of the inner tub4or the pulsator5using a speed-controllable motor such as BLDC is already well known in the washing machine technology field, and a detailed description thereof will be omitted.

The washing machine100can include a water supply unit for supplying water into the outer tub3and a drain unit for draining water from the outer tub3.

The water supply unit can include a water supply valve71for controlling a water supply pipe7connected to a water supply source.

A drawer18can be provided on the water supply pipe7, and when the water supply valve71is opened, the water supplied through the water supply pipe7passes through the drawer18, and then can be supplied into the outer tub3or the inner tub4.

In some implementations, the water supply unit can be provided with a water supply nozzle that directly injects water into the inner tub4without passing through the drawer18.

The drain unit can include a drain pump23provided on a drain pipe21for discharging the water in the outer tub3to the outside. The drain pump23can increase a drain current value as an amount of drainage increases.

In some implementations, the washing machine100can include a control panel that displays an input unit that selects or receives various settings (e.g., course selection, time input, etc.) from a user, and a display unit that displays an operation state (e.g., course progress status, remaining time, etc.) of the washing machine100.

A control unit8can control the operations of components included in the washing machine100and can include a microprocessor. Hereinafter, in describing the control method of the washing machine, it will be understood that the components are controlled by the control unit8unless otherwise specified.

The control unit8can perform a washing cycle, a rinsing cycle, and a spin-drying cycle.

In some implementations, the spin-drying cycle can include a sub spin-drying cycle and a main spin-drying cycle. In addition, the spin-drying cycle can further include a jet rinsing cycle in which water is sprayed onto the laundry through the nozzle43using the centrifugal force of the inner tub4while rotating the inner tub4at a predetermined speed.

In some implementations, the control unit8can control the drain pump23and the motor6. For example, the control unit8can control the operation of the drain pump23and measure the current of the drain pump23. In some implementations, the control unit8can measure and control the rotation speed of the motor6, thereby measuring and controlling the rotation speed of the inner tub4. In addition, the control unit8can spray water through the nozzle43. In some implementations, the control unit8can measure time.

Hereinafter, a method for controlling the spin-drying of the washing machine100will be described.

FIG.3is a flowchart illustrating an exemplary spin-drying control method of a washing machine,FIG.4is a flowchart illustrating an exemplary spin-drying control method of a washing machine in which a jet rinsing cycle is not performed,FIG.5is a diagram describing a control step in a sub spin-drying cycle in a spin-drying control method of an exemplary washing machine,FIG.6is a diagram describing a control step in a jet rinsing cycle in a spin-drying control method of an exemplary washing machine,FIG.7is a diagram describing a control step in a main spin-drying cycle in a spin-drying control method of an exemplary washing machine, andFIG.8is a graph illustrating a change in a rotation speed of an inner tub according to a spin-drying cycle in an exemplary washing machine according.

An exemplary spin-drying control method of a washing machine will be described with reference toFIGS.3to8.

An exemplary spin-drying control method of a washing machine can include a sub spin-drying cycle step (S10), a jet rinsing cycle step (S20), and a main spin-drying cycle step (S30).

In some implementations, a first target speed (W1), a second target speed (W2), a first reference speed (Wr1), a second reference speed (Wr2), a third reference speed (Wr3), a reference current (Ir), a first reference time (tr1), and a second reference time (tr2) can be preset in the control unit8.

In some implementations, the first reference speed (Wr1) can be set to be less than the first target speed (W1) (Wr1<W1).

In some implementations, the control unit8may or may not selectively perform the jet rinsing cycle step (S20).

The sub spin-drying cycle step (S10) can refer to a cycle in which after the rinsing cycle is terminated and all the water used in the rinsing cycle is drained, the moisture from the laundry is removed, but the rotation speed is decreased compared to the rotation speed in the main spin-drying cycle step (S30) to rotate the inner tub4in order to alleviate wrinkling of laundry. For example, if the maximum rotation speed of the inner tub4can be increased to 800 rpm or more and 900 rpm or less in the main spin-drying cycle step (S30), the maximum rotation speed of the inner tub4can be increased to 400 rpm or more and 500 rpm or less in the sub spin-drying cycle step (S10).

The sub spin-drying cycle step (S10) can include a sub spin-drying drainage amount measuring step (S11), a sub spin-drying drainage speed measuring step (S12), and a main spin-drying time setting step (S13).

In the sub spin-drying drainage amount measuring step (S11), the control unit8can rotate the motor6to increase the rotation speed (W) of the inner tub4up to a preset first target speed (W1) to remove moisture from the laundry, and measure the current (I) of the drain pump23to determine the drainage amount. For example, the control unit8can measure a change in the current (I) of the drain pump23and a change in the drainage amount while increasing the rotation speed (W) of the inner tub4to 450 rpm.

If the rotation speed (W) of the inner tub4is gradually increased, the moisture of laundry is discharged to the outer tub3through the through hole defined in the inner tub4by centrifugal force, and the water in the outer tub3may be discharged to the outside by the operation of the drain pump23after flowing into the drain pipe21. In some implementations, if the drain pump23operates, the current (I) required for the operation increases in proportion to the increase in the drainage amount. Therefore, the control unit8can measure the current (I) of the drain pump23to determine the drainage amount during the sub spin-drying cycle.

In the sub spin-drying drainage speed measuring step (S12), the control unit can measure the rotation speed (Wt) of the inner tub4when the current (I) of the drain pump23increases and then decreases to or below a preset reference current (Ir) (I≤Ir).

When the rotation speed (W) of the inner tub4is gradually increased in the sub spin-drying cycle step (S10), the current (I) of the drain pump23increases rapidly and then decreases and maintains a predetermined current (this is referred to as ‘intermediate current’), and then decreases once more and maintains a predetermined current range (this can be referred to as ‘minimum current’). In some implementations, maintaining the minimum current range may refer that sufficient drainage has already been made.

Accordingly, the point in time when the reference current (Ir) is set higher than the minimum current (lower than the intermediate current), and the current (I) of the drain pump23increases and then decreases to or below the reference current (Ir) (I≤Ir) can be seen as the point in time when sufficient drainage is made.

In the main spin-drying time setting step (S13), the control unit8can set (change) the rotation time (T) of the inner tub4in the main spin-drying cycle based on the rotation speed (Wt) of the inner tub4measured in the sub spin-drying drainage speed measuring step (S12).

The rotation time (T) of the inner tub4in the main spin-drying cycle can be preset (Ti) in the control unit8. In some implementations, the rotation time (T) of the inner tub4may be directly input by the user through an input unit, and the control unit8can set the rotation time (T) of the inner tub4by detecting the amount (weight) of laundry.

However, when the user inputs the expected time (Ti) as the rotation time of the inner tub4(T=Ti), or the control unit8sets the rotation time of the inner tub4as the time (Ti) calculated simply through the amount (mass) of the laundry (T=Ti), it does not reflect how much water the laundry contains during the washing and rinsing cycles and the drainage properties of the laundry. Accordingly, there may be problems in that the laundry is wet due to insufficient dehydration, or the laundry is wrinkled due to excessive dehydration.

In order to solve this problem, in some implementations, when, in a state (W=W1) in which the rotation speed (W) of the inner tub4is increased to the first target speed (W1), the current (I) of the drain pump23exceeds the reference current (Ir) (I>Ir), the control unit8may no longer increase the rotation speed (W) of the inner tub4, so that it is determined that the laundry retains a lot of moisture and, the rotation time may be set as the extension time (Te) (T=Te) by extending the preset rotation time (Ti) of the inner tub4in the main spin-drying cycle step. In some implementations, the extension time (Te) can be set to be greater than the preset rotation time (Ti) of the inner tub4(Te>Ti).

In some implementations, when the rotation speed (Wt) of the inner tub4measured in the sub spin-drying drainage speed measuring step (S12) is less than the preset first reference speed (Wr1) (Wt<Wr1), the control unit8can determine that the laundry has a little moisture, and shorten the preset rotation time (Ti) of the inner tub in the main spin-drying cycle. For example, when the rotation speed (Wt) of the inner tub4measured in the sub spin-drying drainage speed measuring step (S12) is less than the preset first reference speed (Wr1) (Wt<Wr1), the control unit8can shorten the preset rotation time (Ti) of the inner tub and set it as the shortened time (Ts). In some implementations, the shortened time (Ts) can be set to be smaller (Ts<Ti) than the preset rotation time (Ti) of the inner tub4in the main spin-drying cycle step.

In some implementations, when the rotation speed (Wt) of the inner tub4measured in the sub spin-drying drainage speed measuring step (S12) is greater than or equal to the preset first reference speed (Wr1) and less than or equal to the first target speed (W1) (Wr1≤Wt≤W1), the preset rotation time (Ti) of the inner tub can be maintained (T=Ti).

In some implementations, when the rotation speed (Wt) of the inner tub4measured in the sub spin-drying drainage speed measuring step (S12) is less than the preset first reference speed (Wr1) (Wt<Wr1), the preset maximum rotation speed of the inner tub4can be reduced in the main spin-drying cycle (which may mean a second target speed to be described later).

The jet rinsing cycle step (S20) can refer to a cycle in which the laundry is rinsed by spraying water to the laundry through the nozzle43while the inner tub4is rotated at a predetermined rotation speed after the sub spin-drying cycle step (S10).

The jet rinsing cycle step (S20) can include a jet rinsing drainage amount measuring step (S21), a jet rinsing drainage time measuring step (S22), and a main spin-drying time correcting step (S23).

In the jet rinsing drainage amount measuring step (S21), the inner tub4can maintained at a predetermined rotation speed (Wj) and rotated while water is sprayed onto the laundry using the centrifugal force of the inner tub4, and the current (I) of the drain pump23can be measured. For example, in the jet rinsing drainage amount measuring step (S21), while maintaining the rotation speed of the inner tub4at 90 rpm or more and 110 rpm or less, water is sprayed on the laundry, and the current (I) of the drain pump23can be measured.

In the jet rinsing drainage time measuring step (S22), the time (Δt) from the point in time when water is started to be sprayed in the jet rinsing drainage amount measuring step (S21) to the point in time when the current (I) of the drain pump23increases to the reference current (Ir) or greater (Ir≥Ir) can be measured.

In the jet rinsing drainage time measuring step (S22), since the inner tub4rotates while maintaining a predetermined rotation speed range and at the same time, water is supplied to the laundry, the drainage property (drainage capacity) of the laundry through the time (Δt) from the point in time when water is supplied to the laundry to the point in time when the supplied water is drained again can be determined.

In the main spin-drying time correcting step (S23), the rotation time (T) of the inner tub set in the main spin-drying time setting step (S13) can be corrected (T1) based on the time (Δt) measured in the jet rinsing drainage time measuring step (S22).

In some implementations, the first reference time (tr1) and the second reference time (tr2) can be set in the control unit8, and the first reference time (tr1) can be set to be greater than the second reference time (tr2) (tr1>tr2).

In some implementations, when the time (Δt) measured in the jet rinsing drainage time measuring step (S22) exceeds the first reference time (tr1) (Δt>tr1), it is determined that the drainage capacity of the laundry is low, and the rotation time (T) of the inner tub set in the main spin-drying time setting step (S13) can be further extended. For example, as the value obtained by subtracting the first reference time (tr1) from the time Δt measured in the jet rinsing drainage time measuring step (S22) increases, the rotation time (T) of the inner tub set in the main spin-drying time setting step (S13) can be corrected to increase in proportion to the obtained value. In addition, an additional time (te1) is given by setting a section for a value obtained by subtracting the first reference time (tr1) from the time (Δt) measured in the jet rinsing drainage time measuring step (S22), and this may be added to the rotation time (T) of the inner tub set in the main spin-drying time setting step (S13) (T1=T+te1).

In some implementations, when the time (Δt) measured in the jet rinsing drainage time measuring step (S22) is less than the second reference time (tr2) (Δt<tr2), it is determined that the laundry has a high drainage capacity, and the rotation time (T) of the inner tub set in the main spin-drying time setting step (S13) can be shorten. For example, as the value obtained by subtracting the time (Δt) measured in the jet rinsing drainage time measuring step (S22) from the second reference time (tr2) increases, the rotation time (T) of the inner tub measured in the main spin-drying time setting step (S13) can be corrected to decrease in proportion to the obtained value. In addition, a shortened time (ts1) is given by setting a section for a value obtained by subtracting the time (Δt) measured in the jet rinsing drainage time measuring step (S22) from the second reference time (tr2), and this can be subtracted from the rotation time (T) of the inner tub set in the main spin-drying time setting step (S13) (T1=T−ts1).

In some implementations, when the time (Δt) measured in the jet rinsing drainage time measuring step (S22) is equal to or less than the first reference time and greater than or equal to the second reference time (tr2) (tr2≤Δt≤tr1), the rotation time of the inner tub set in the main spin-drying time setting step (S13) can be maintained (T1=T).

The main spin-drying cycle step (S30) can refer to a cycle in which the inner tub4is rotated in order to remove moisture from the laundry after the jet rinsing cycle step (S20) (if the jet rinsing cycle step (S20) is not performed, after the sub spin-drying cycle step (S10)).

The main spin-drying cycle step (S30) can include a main spin-drying drainage amount measuring step (S31), a main spin-drying drainage speed measuring step (S32), and a main spin-drying time adjusting step (S33).

In the main spin-drying drainage amount measuring step (S31), the control unit8may measure the current (I) of the drain pump23while increasing the rotation speed (W) of the inner tub4to a preset second target speed (W2). For example, the control unit8may measure the change in the current (I) of the drain pump23and determine the change in the drainage amount while increasing the rotation speed (W) of the inner tub4to 840 rpm.

In the main spin-drying drainage speed measuring step (S32), the control unit8can measure the rotation speed of the inner tub when the current of the drain pump increases and then decreases to or below the reference current.

Referring toFIG.4, when the rotation speed (W) of the inner tub4gradually increases in the main spin-drying cycle step (S30), it can be seen that the current (I) of the drain pump23rapidly increases and then decreases, and is maintained to a minimum. In some implementations, maintaining the minimum current range can refer that sufficient drainage has already been made.

Accordingly, it can be seen that the point in time when the current (I) of the drain pump23increases and then decreases to or below the reference current (Ir) (I≤Ir) is the point in time when sufficient drainage is achieved.

Hereinafter, a case in which the jet rinsing cycle step (S20) is not performed and a case in which the jet rinsing cycle step (S20) is performed will be separately described.

First, in the case where the jet rinsing cycle step (S20) is not performed, the control unit8can control (T2) the rotation time (T) of the inner tub4measured in the main spin-drying time setting step (S13) based on the rotation speed (Wt) of the inner tub4set in the main spin-drying drainage speed setting step (S32), in the main spin-drying time adjusting step (S33).

In some implementations, when the rotation speed (Wt) of the inner tub4measured in the main spin-drying drainage speed measuring step (S32) exceeds a preset second reference speed (Wr2) (Wt>Wr2), the control unit8can extend the rotation time (T) of the inner tub set in the main spin-drying time setting step (S13) (T2>T). For example, based on the value obtained by subtracting the preset second reference speed (Wr2) from the rotation speed (Wt) of the inner tub4measured in the main spin-drying drainage speed measuring step (S32), the rotation time (T) of the inner tub set in the main spin-drying time setting step (S13) can be corrected to increase in proportion to the obtained value. In addition, an additional time (te2) is given by setting a section for a value obtained by subtracting the second reference speed (Wr2) from the rotation speed (Wt) of the inner tub4measured in the main spin-drying drainage speed measuring step (S32), and this can be added to the rotation time (T) of the inner tub set in the main spin-drying time setting step (S13) (T2=T+te2).

In some implementations, when the rotation speed (Wt) of the inner tub4measured in the main spin-drying drainage speed measuring step (S32) is less than a preset third reference speed (Wr3) (Wt<Wr3), the control unit8can shorten the rotation time (T) of the inner tub set in the main spin-drying time setting step (S13) (T2<T). For example, based on the value obtained by subtracting the rotation speed (Wt) of the inner tub4measured in the main spin-drying drainage speed measuring step (S32) from the third reference speed (Wr3), the rotation time (T) of the inner tub set in the main spin-drying time setting step (S13) can be corrected to decrease in proportion to the obtained value. In addition, a shortened time (ts2) is given by setting a section for a value obtained by subtracting the rotation speed (Wt) of the inner tub4measured in the main spin-drying drainage speed measuring step (S32) from the third reference speed (Wr3), and this can be subtracted from the rotation time (T) of the inner tub set in the main spin-drying time setting step (S13) (T2=T−ts2).

In some implementations, when the rotation speed (Wt) of the inner tub4measured in the main spin-drying drainage speed measuring step (S32) is less than or equal to the second reference speed (Wr2) and greater than or equal to the third reference speed (Wr3) (Wr3≤Wt≤Wr2), the rotation time (T2=T) of the inner tub set in the main spin-drying time setting step (S13) can be maintained.

In some implementations, when performing the jet rinsing cycle step (S20), the control unit8can control the rotation time (T1) of the inner tub set in the main spin-drying time correcting step (S23) based on the rotation speed (Wt) of the inner tub4measured in the main spin-drying drainage speed measuring step (S32), in the main spin-drying time adjusting step (S33).

Therefore, when the rotation speed (Wt) of the inner tub4measured in the main spin-drying drainage speed measuring step (S32) exceeds the preset second reference speed (Wr2) (Wt>Wr2), the control unit8can extend the rotation time (T1) of the inner tub set in the main spin-drying time correcting step (S23) (T2>T1).

Accordingly, when the rotation speed (Wt) of the inner tub4measured in the main spin-drying drainage speed measuring step (S32) is less than the preset third reference speed (Wr3) (Wt<Wr3), the control unit8can shorten the rotation time (T1) of the inner tub measured in the main spin-drying time correcting step (S23) (T2<T1).

In some implementations, when the rotation speed (Wt) of the inner tub4measured in the main spin-drying drainage speed measuring step (S32) is less than or equal to the second reference speed (W2) and greater than or equal to the third reference speed (W3) (W3≤Wt≤W2), the rotation time of the inner tub set in the main spin-drying time correcting step (S23) can be maintained (T2=T1).

FIG.9is a flowchart illustrating another exemplary spin-drying control method of a washing machine, andFIG.10is a graph illustrating a current value and drainage amount of a drain pump according to a rotation of an inner tub in another exemplary washing machine.

Another exemplary spin-drying control method of a washing machine will be described with reference toFIGS.9and10.

In some implementations, a target speed (W1), a reference current (Ir), and a reference time (Tr) can be set in the control unit8. For example, the target speed (W1) can be set to 800 rpm or more and 900 rpm or less, the reference current (Ir) can be set to 65 mA or more and 75 mA or less, and the reference time (Tr) can be set to 1 minute and 30 seconds or more and 2 minutes or less, but is not limited thereto, and can be changed according to the capacity of the washing machine.

The another exemplary spin-drying control method of the washing machine can include a stop time setting step (S205[JWS1]), a spin-drying starting step (S210), a drain stopping step (S220), a drainage amount determining step (S230), a spin-drying time adjusting step (S240), a re-stopping step (S250), and a spin-drying termination determining step (S260).

In some implementations, the stop time setting step (S205) can be performed during the sub spin-drying cycle. The spin-drying starting step (S210), the drain stopping step (S220), the drainage amount determining step (S230), the spin-drying time adjusting step (S240), the re-stopping step (S250), and the spin-drying termination determining step (S260) can be performed during the main spin-drying cycle.

The sub spin-drying cycle can refer to a cycle in which moisture is removed from the laundry after all the water used in the rinsing cycle is drained, and the inner tub4is rotated with the decreased rotation speed relatively compared to a rotation speed in the main spin-drying cycle in order to alleviate wrinkling of the laundry.

In the stop time setting step (S205), the control unit8can rotate the motor6to increase the rotation speed (W) of the inner tub4to a preset sub spin-drying target speed while removing the moisture in the laundry, and can measure the current (I) of the drain pump23to determine the drainage amount. For example, the control unit8can measure a change in the current (I) of the drain pump23while increasing the rotation speed (W) of the inner tub4to 450 rpm.

When the rotation speed (W) of the inner tub4is gradually increased, the moisture of laundry may be discharged to the outer tub3through the through hole defined in the inner tub4by centrifugal force. After the water in the outer tub3flows into the drain pipe21, the water may be discharged to the outside by the operation of the drain pump23. In some implementations, when the drain pump23operates, the current (I) required for the operation increases in proportion to the increase in the drainage amount. Therefore, the control unit8can measure the current (I) of the drain pump23to determine the drainage amount during the sub spin-drying cycle.

In some implementations, the control unit8can measure the rotation speed (Wt) of the inner tub4when the current (I) of the drain pump23increases and then decreases to or below a preset sensing current (Is) (I≤Is).

When the rotation speed (W) of the inner tub4gradually increases in the sub spin-drying cycle, the current (I) of the drain pump23rapidly increases and then decreases to maintain a predetermined current range. In some implementations, maintaining the predetermined current range can refer that sufficient drainage has already been made.

Accordingly, it can be seen that the point in time when the current (I) of the drain pump23increases and then decreases to or below the sensing current (Is) (I≤Is) is the point in time when sufficient drainage is achieved.

Then, by measuring the rotation speed (Wt) of the inner tub4at a time when the current (I) of the drain pump23is decreased to or below the detection current (Is) (I≤Is), the moisture content of the laundry can be predicted.

Thus, as the measured rotation speed (Wt) of the inner tub4increases, sufficient drainage is possible only when the high rotation speed is reached, which means that the laundry contains a lot of moisture.

Therefore, in the stop time setting step (S205), the control unit8determines the moisture content of the laundry based on the rotation speed (Wt) of the inner tub4when the current (I) of the drain pump increases and then decreases to or below the detection current (Is) (I≤Is), and can set the stop time (Tp) of the drain pump in the drain stopping step (S220) in proportion to the moisture content.

In some implementations, the control unit8can set the spin-drying time (Ts) in proportion to the moisture content.

In the spin-drying starting step (S210), the control unit8can drive the motor6to rotate the inner tub4, and can drive the drain pump23. Therefore, the control unit8can start the main spin-drying cycle.

Then, the control unit8can control the washing machine to dehydrate the laundry while increasing the rotation speed (W) of the inner tub4to the preset target speed (W1). In some implementations, the current (I) of the drain pump23rapidly increases and then starts to decrease (seeFIG.4).

When the rotation speed (W) of the inner tub4reaches a preset target speed (W=W1) in the spin-drying starting step (S210), the drain stopping step (S220) can be started.

In some implementations, after the rotation speed (W) of the inner tub4reaches the target speed (W1), the control unit8can maintain the rotation speed of the inner tub4(W=W1) until the spin-drying cycle is terminated. However, the control unit8may increase the rotation speed (W) of the inner tub4(W>W1) through the spin-drying time adjusting step (S40), which will be described later.

In the drain stopping step (S220), the control unit8can stop the drain pump23for the preset stop time (Tp).

In some implementations, the stop time (Tp) may be set based on the moisture content of the laundry in the stop time setting step (S205).

In some implementations, the control unit8can detect the weight of laundry and set the stop time (Tp) to be longer as the laundry amount is larger (heavier) based on the laundry amount.

In some implementations, the stop time (Tp) is set to 10 seconds or less, but is not limited thereto, and may be changed according to the capacity of the washing machine100and the capacity and performance of the drain pump.

The drainage amount determining step S230can be performed after the stop time (Tp) of the drain stopping step (S220) has elapsed.

In the drainage amount determining step (S230), the control unit8can drive the drain pump23stopped in the drain stopping step (S220) again for a predetermined time, and then can measure the current value (I) of the drain pump23. For example, the control unit8can measure the current value (I) of the drain pump23after the drain pump23is driven again for 30 seconds, but is not limited thereto, and it can be changed according to the capacity of the washing machine100and the capacity and performance of the drain pump.

In the drainage amount determining step (S230), the control unit8can determine whether the current value (I) of the drain pump23exceeds the preset reference current value (Ir).

In the spin-drying time adjusting step (S240), the control unit8can change the spin-drying time by comparing the time (T) elapsed since the inner tub4starts to rotate with a preset reference time (Tr) when the current value (I) of the drain pump23measured in the drainage amount determining step (S230) exceeds the reference current value (Ir) (I>Ir).

In some implementations, the time (T) elapsed after the inner tub4starts to rotate may refer to the interval from the point in time when the inner tub4starts to rotate in the spin-drying starting step (S210) to the point in time when the current value (I) of the drain pump23is measured in the drainage amount determining step (S230).

In the spin-drying time adjusting step (S240), the control unit8can increase the preset spin-drying time (Ts) by a predetermined time (t1) (Ts1=Ts+t1) when the time (T) elapsed since the inner tub (4) starts to rotate exceeds the reference time (Tr) (T>Tr) (S241).

In some implementations, the spin-drying time (Ts) may mean from a point in time when the inner tub4starts to rotate in the spin-drying starting step (S210) to a point in time when the inner tub4stops to rotate and the spin-drying cycle is terminated.

In addition, increasing the spin-drying time may mean delaying a point in time when the inner tub4stops to rotation at the preset spin-drying time by a predetermined time (t1).

In the spin-drying time adjusting step (S240), the control unit8can increase the rotation speed (W) of the inner tub4(W>W1) when the time (T) elapsed since the inner tub4starts to rotate exceeds the reference time (Tr) (T>Tr) (S242).

In the spin-drying time adjusting step (S240), the control unit8can shorten the stop time (Tp) for stopping the driving of the drain pump23by a predetermined time (t2) (Tp1=Tp−t2) when the time (T) elapsed since the inner tub4starts to rotate exceeds the reference time (Tr) (T>Tr). For example, when the preset stop time (Tp) is 9 seconds, it can be shortened to 8 seconds (Tp1<Tp) (S243).

In some implementations, in the spin-drying time adjusting step (S240), the control unit8can selectively perform the increase of the spin-drying time (Ts) (S241), the increase of the rotation speed of the inner tub4(S242), or the shortening (S243) of the stop time (Tp), and the control unit8can perform by combining any two of them, or may perform all of them.

Therefore, in some implementations, the stop time (Tp) of the drain pump23can be set based on the moisture content in the laundry or the amount of laundry, and the current value (I) of the drain pump23can be measured during the spin-drying cycle to determine the moisture drainage ability of the laundry, and correspondingly, a constant degree of dehydration can be provided by resetting the spin-drying cycle time (Ts) and the rotation speed (W) of the inner tub4.

After the spin-drying time adjusting step (S240), the control unit8can perform the drain stopping step (S220).

In some implementations, in the spin-drying time adjusting step (S240), the control unit8can perform the drain stopping step (S220) when the time (T) elapsed since the inner tub4starts to rotate is less than or equal to the reference time (Tr) (T≤Tr).

In some implementations, when the current value (I) of the drain pump23measured in the drainage amount determining step (S230) is less than or equal to the reference current value (Ir) (I≤Ir), the control unit8can control the re-stopping step (S250).

In the re-stopping step (S250), the control unit8can stop the operation of the drain pump23for the stop time (Tp).

In some implementations, when the stop time (Tp) is shortened (Tp1) in the spin-drying time adjusting step (S240) and then the re-stopping step (S250) is started, the originally input stop time (Tp) can be restored, and then the driving of the drain pump23can be stopped.

In some implementations, when the stop time (Tp) is shortened (Tp1=Tp−t2) in the spin-drying time adjusting step (S240) and then the re-stopping step (S250) is started, the driving of the drain pump23can be stopped with the shortened stop time (Tp1=Tp−t2).

In some implementations, in the re-stopping step (S250), the control unit8can stop the driving of the drain pump23, but may shorten the previously input stop time (Tp) by a predetermined time (t3) (Tp−t3).

The spin-drying termination determining step (S260) can be performed after the stop time of the re-stopping step (S250) has elapsed.

In the spin-drying termination determining step S260, the control unit8can measure the current value (I) of the drain pump23again after driving the drain pump23again for a predetermined time. Then, by comparing the remeasured current value (I) of the drain pump23with the reference current value (Ir), the control unit can determine whether to terminate the spin-drying cycle.

In the spin-drying termination determining step (S260), the control unit8can perform the spin-drying time adjusting step (S240) when the remeasured current value (I) of the drain pump23exceeds the reference current value (Ir) (I>Ir).

In the spin-drying termination determining step (S260), the control unit8can terminate the spin-drying cycle when the remeasured current value (I) of the drain pump is less than or equal to the reference current value (I≤Ir).