CN111527255A

CN111527255A - Method for controlling washing machine

Info

Publication number: CN111527255A
Application number: CN201880084699.0A
Authority: CN
Inventors: 林明训; 郑还镇; 金宰铉; 李订勋; 禹景喆
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2017-12-28
Filing date: 2018-12-28
Publication date: 2020-08-11
Anticipated expiration: 2038-12-28
Also published as: CN115450020A; AU2022203579A1; AU2018394999A1; KR102457411B1; CN111527255B; KR20190080677A

Abstract

The present disclosure is a method for controlling a washing machine having a tub for containing water, a drum rotatably disposed in the tub, at least one spray nozzle disposed in front of the drum to spray water toward the drum, a washing motor configured to rotate the drum, and a circulation pump configured to circulate water discharged from the tub to the at least one spray nozzle, the method comprising: a step (a) of supplying water having detergent into an outer tub to reach a first water level; a step (b) of operating the circulation pump at a first speed such that the washing motor is repeatedly accelerated and braked when the circulation pump is operated at the first speed, causing laundry in the drum to be adsorbed to the inner circumferential surface of the drum in response to acceleration of the washing motor, and causing the laundry to fall from the inner circumferential surface of the drum in response to deceleration of the washing motor; wherein the first speed is set in a range in which water discharged from the circulation pump cannot reach the at least one nozzle or even if the water reaches the at least one nozzle, the sprayed water cannot reach the inner circumferential surface of the drum; a step (c) of supplying water into the outer tub such that a water level in the outer tub rises from a first water level to a second water level; and a step (d) of repeating the acceleration and deceleration of the washing motor such that the circulation pump is accelerated in response to the acceleration of the washing motor and the circulation pump is decelerated in response to the deceleration of the washing motor.

Description

Method for controlling washing machine

Technical Field

The present invention relates to a method for controlling a washing machine having a circulation pump for circulating wash water.

Background

In general, a washing machine is a general term for a device that removes contaminants from laundry, bedsheets, etc. (hereinafter, referred to as "laundry") using chemical decomposition of detergent and water and physical force such as friction between water and the laundry. The washing machine has a rotary cylindrical drum installed in an outer tub for containing water, and a plurality of through holes are formed in the rotary cylindrical drum. If the washing machine is operated with laundry loaded in the drum, water having detergent is supplied into the tub and/or the drum, and then the drum starts to rotate, performing a washing operation.

In order to improve washing performance and prevent the laundry from being contaminated by the detergent, the detergent supplied to the water needs to be uniformly dissolved. Generally, water having detergent is supplied in an initial washing operation, a drum is filled with water to a certain level while rotating, and the water is agitated to dissolve the detergent while the drum is rotating.

However, this method is applicable only when the water level in the tub is high enough to fill water to a certain level in the drum, and thus, if a predetermined amount of detergent is provided, the concentration level of the washing water does not exceed a predetermined level. Further, some of the supplied water with the detergent (hereinafter, referred to as "wash water") is absorbed into the laundry, and thus the water level in the outer tub is lowered. In order to compensate for the lowered water level, it is necessary to additionally supply more water, which results in a further reduction in the concentration level of the washing water. Therefore, the laundry cannot be washed using the washing water in which the detergent is highly concentrated.

Further, in this method, the region distant from the drum is less affected by the rotation of the drum, and therefore, in such a region, the water flow is not strong and the detergent cannot be sufficiently dissolved. For example, the detergent may not be sufficiently dissolved in a drain bellows configured to guide water discharged from the outer tub to the circulation pump or in the circulation pump case.

Japanese patent application publication No.2010036016A (hereinafter, referred to as "related art 1") discloses a washing machine in which washing water is circulated using a circulation pump employing a BLDC motor and is sprayed into a drum (water container). In the normal operation, the related art rotates the circulation pump at 2500rpm to provide the circulating water to the deep region inside the drum at a high angle, and when the amount of the laundry sensed by the load amount sensing means is determined to be less than a predetermined value, the related art rotates the circulation pump at 2500rpm to soak the laundry located at the bottom of the drum at a low angle. The related art 1 adjusts the speed of the circulation pump, but still sprays the circulation water into the drum, and thus it is still difficult to form washing water in which the detergent is highly concentrated before the water is applied to the laundry.

Japanese patent application publication No.2008113982A (hereinafter, referred to as "related art 2") discloses a washing machine having a circulation pump capable of rotating forward/backward. The circulation pump includes an impeller disposed in a housing having two outlets. One of the two discharge ports (hereinafter, referred to as "first outlet port") is used to dissolve the detergent, and the other of the two discharge ports (hereinafter, referred to as "second outlet port") is used to supply the circulating water to the circulating nozzle. In the housing, there is a first barrier configured to prevent water from being discharged through the second outlet port when the impeller rotates backward, and a second barrier configured to prevent water from being discharged through the first outlet port when the impeller rotates forward.

The water (detergent-dissolved water) discharged through the first outlet by the backward rotation of the impeller flows along a predetermined pipe and is recovered back to the outer tub through an inlet hole formed at the bottom of the outer tub (water tank). That is, when the impeller rotates backward, water circulates in a manner in which water discharged from the outer tub is pumped by the circulation pump and flows back into the outer tub. In particular, in this process, the circulating water does not flow into the drum, but reaches only a concave space provided at a lower side of the tub, which is not in contact with the drum, and thus, it is possible to prevent incompletely dissolved detergent from being applied to the laundry in the drum and to form washing water in which the detergent is highly concentrated before water is applied to the laundry.

However, the related art 1 needs to have an additional flow path for dissolving the detergent and a flow path for spraying the washing water into the drum.

Further, in the related art 2, as the backward rotation speed of the impeller increases, the flow rate at the first outlet port increases, thereby reducing the circulation period of the washing water. Therefore, the washing water is not agitated by the impeller during one cycle period.

Disclosure of Invention

Technical problem

A first object of the present invention is to provide a method for controlling a washing machine, which enables a detergent to be uniformly dissolved in wash water using a circulation pump.

A second object of the present invention is to provide a method for controlling a washing machine, which enables laundry to be uniformly soaked in washing water in which detergent is dissolved.

A third object of the present invention is to provide a method for controlling a washing machine, which prevents laundry from being contaminated by incompletely dissolved detergent.

A fourth object of the present invention is to provide a washing machine and a method for controlling the same, which perform a detergent dissolving step using a nozzle for spraying circulating water pumped by a circulating pump, wherein the circulating water is prevented from reaching the inside of a drum during the detergent dissolving step, so as to prevent incompletely dissolved detergent from being applied to laundry.

These objects are achieved by the features of the claims.

Technical scheme

In one general aspect of the present invention, there is provided a method for controlling a washing machine having a tub for containing water, a drum rotatably disposed in the tub, at least one spray nozzle disposed in front of the drum to spray water toward the drum, a washing motor configured to rotate the drum, and a circulation pump configured to circulate water discharged from the tub to the at least one spray nozzle.

The method comprises the following steps: a step of supplying water having detergent into the outer tub to a first water level; and a step of operating the circulation pump at a first speed. The first speed is set in a range in which water discharged from the circulation pump cannot reach any one of the at least one nozzle, or even if the water reaches the at least one nozzle, the sprayed water cannot reach the inside of the drum.

When the circulation pump is operated at the first speed, the wash pump is repeatedly accelerated to brake. The laundry in the drum is adsorbed to the inner circumferential surface of the drum in response to acceleration of the washing motor, and the laundry drops from the inner circumferential surface of the drum in response to deceleration of the washing motor.

The braking of the washing motor may be performed when the laundry is lifted from the lowest position in the drum to a height corresponding to a set angle, i.e., a rotation angle set to be less than 180 degrees of the drum.

The first speed may be equal to or less than 1500 rpm.

Then, a step of repeatedly operating and stopping the circulation pump a plurality of times while continuously rotating the washing motor in one direction (hereinafter, referred to as "washing step") may be performed. When the washing motor is continuously rotated in the washing step, the laundry in the drum may be repeatedly lifted to and dropped from a predetermined height while the washing motor is continuously rotated in one direction. In this case, after the drum 360 rotates 360 degrees or more, the washing motor may be decelerated.

The step of additionally supplying water into the outer tub may be further performed in the washing step. In the washing step, when the operation of the circulation pump is performed a plurality of times and the operation of the circulation pump is performed after the water is additionally supplied into the outer tub, the rotation speed of the circulation pump may be set to be higher than that in the previous operation.

In the step (e), the circulation pump may be repeatedly operated a plurality of times in response to a plurality of consecutive rotations of the washing motor in one direction, and the plurality of operations of the circulation pump may include: a first operation in which the circulation pump is rotated at a first rotation speed; and a second operation in which the circulation pump is rotated at a second rotation speed higher than the first rotation speed after the first operation.

The at least one nozzle may include: two or more lower nozzles spraying water to a first region on an inner circumferential surface of the drum; and two or more middle nozzles supplied with water along a flow path shared with the two or more lower nozzles and disposed higher than the two or more lower nozzles in the flow path so as to spray water to a second region on the inner circumferential surface of the drum. The rotation of the circulation pump may be controlled in the washing step such that water is sprayed from the two or more lower nozzles and the two or more middle nozzles.

In the washing step, the step of controlling the circulation pump may be performed such that the water pumped by the circulation pump is sprayed through the two or more lower nozzles to fail to reach the two or more nozzles.

The washing machine may further include a direct water nozzle (direct water nozzle) for spraying water supplied through the water supply valve into the drum. The washing step may include the steps of: the water supply valve is opened to spray water through the direct water nozzle while spraying water through the two or more middle nozzles and the two or more lower nozzles.

After the washing step, a step of accelerating the washing motor to a contact maintaining speed to rotate the laundry in the drum while being adsorbed to the inner circumferential surface of the drum and rotating the washing motor while maintaining the contact maintaining speed (contact maintaining speed), and a step of accelerating the circulation pump in response to the acceleration of the washing motor to spray water through the at least one nozzle may be further performed.

The invention has the advantages of

The control method for a washing machine according to the present invention causes wash water to be agitated by a circulation pump at a low water level, thereby uniformly dissolving detergent in the wash water. Then, since the washing water is supplied to the laundry through the at least one nozzle and the water level rises due to the additional water supply, the detergent can be uniformly applied to the laundry, and the incompletely dissolved detergent residues do not remain in the laundry after the washing is completed.

The method of controlling a washing machine according to the present invention utilizes washing water in which detergent is highly concentrated in an initial washing stage, thereby improving washing performance. That is, as the water level in the outer tub is gradually increased, contaminants may be removed from the laundry with the washing water highly concentrated with the detergent at the initial washing stage, and then the laundry may be washed in the outer tub using the rising water level using the water current sprayed from the nozzle, thereby improving washing performance.

Further, since the circulation pump motor may be controlled to vary the number of water streams sprayed from the plurality of nozzles during washing, washing may be performed by adjusting the amount of circulating water according to the water level.

Further, since the detergent dissolving step is performed using the nozzle formed in the gasket, a simple structure may be achieved without an additional circulation flow path for the detergent dissolving step, and the detergent dissolving step may be easily performed using an existing washing machine.

Drawings

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

fig. 1 is a perspective view illustrating a washing machine according to an embodiment of the present invention;

fig. 2 is a sectional view illustrating the washing machine shown in fig. 1;

fig. 3 is a block diagram illustrating a control relationship between main components of the washing machine according to an embodiment of the present invention;

fig. 4 is a view schematically showing main components of a washing machine according to an embodiment of the present invention;

FIG. 5 schematically illustrates a front view of the drum, showing the spray range of each nozzle;

FIG. 6 schematically illustrates a side view of the drum showing the spray range of each nozzle;

fig. 7 is a diagram illustrating various drum driving actions that may be implemented by the washing machine according to the embodiment of the present invention;

fig. 8 is a graph for comparing washing performance and vibration degree between various drum driving motions;

fig. 9 is a diagram for explaining an ejection action in each of the drum driving actions of the present invention compared with the conventional action;

fig. 10 is a flowchart illustrating a method for controlling a washing motor and a circulation pump motor in a drum driving action;

fig. 11 shows the entire washing sequence of the washing machine applicable to the present invention;

fig. 12 is a graph showing the speed (a) of the washing motor and the speed (b) of the circulation pump motor in the tumbling motion and the tumbling motion;

fig. 13 is a graph for explaining how a washing motor and a circulation pump motor operate in a shaking motion, a scrubbing motion, and a beating motion according to an embodiment of the present invention;

fig. 14 illustrates a variation (a) in the number of rotations (a) of the drum and a variation (b) in the number of rotations of the pump according to an embodiment of the present invention;

fig. 15 shows the arrangement of the laundry in the drum in the middle of the filtering action;

fig. 16 is a graph comparing between the speeds of the circulation pump motor in each drum driving action when the laundry load (laundry load) falls within the first laundry load range I and when the laundry load falls within the second laundry load range II;

fig. 17 illustrates a change (a) in the number of times of (rotation) of the drum and a change (b) in the number of times of (rotation) of the pump according to an embodiment of the present invention;

fig. 18 is a view for explaining a pressing action according to an embodiment of the present invention;

fig. 19 is a view for explaining a water supply/laundry soaking cycle according to an embodiment of the present invention;

fig. 20 is a diagram for explaining a method for controlling a washing machine according to an embodiment of the present invention; and

fig. 21 is a diagram for explaining a method for controlling a washing machine according to another embodiment of the present invention.

Detailed Description

Fig. 1 is a perspective view illustrating a washing machine according to an embodiment of the present invention. Fig. 2 is a sectional view illustrating the washing machine shown in fig. 1. Fig. 3 is a block diagram illustrating a control relationship between main components of the washing machine according to an embodiment of the present invention. Fig. 4 is a diagram schematically illustrating main components of a washing machine according to an embodiment of the present invention.

Referring to fig. 1 to 4, a housing 10 defines an external appearance of the washing machine, and an input hole 12h through which laundry is loaded is formed on a front surface of the housing 10. The case 10 may include: a cabinet (cabinet) 11 having an open front surface (open front surface), a left surface, a right surface, and a rear surface; and a front panel 12 coupled to the open front surface of the cabinet 11. The input hole 12h may be formed on the front panel 12. The cabinet 11 may have an open bottom surface and an open top surface, and the horizontal base 1 for supporting the washing machine may be coupled to the bottom surface of the cabinet 11. The housing 10 may further include: a top plate 13 covering the open top surface of the cabinet 11; and a control panel 14 disposed on an upper side of the front panel 12.

The control panel 14 may include: an input unit (e.g., a button, dial, touch pad, etc.) for receiving various settings regarding the operation of the washing machine from a user; and a display unit (e.g., LCD, LED display, etc.) for displaying an operation state of the washing machine.

A door 20 for opening and closing the access hole 12h is rotatably coupled to the housing 10. The door 20 may include: a door frame 21 having an opening portion near the center thereof and rotatably coupled to the front panel 12; and a window 22 installed at a central portion of the opening of the door frame 21.

An outer tub 31 for containing water may be provided in the case 10. An inlet hole for receiving laundry is formed on a front surface of the outer tub 31, and communicates with the input hole 12h of the casing 10 through the gasket 60.

The gasket 60 serves to prevent water contained in the outer tub 31 from leaking. The front end of the gasket 60 is coupled to the front surface (or the front panel 12) of the casing 10, and the rear end of the gasket 60 is coupled to the inlet hole of the outer tub 31, and a portion between the front end and the rear end extends in a tubular shape. The gasket 60 may be formed of a flexible material or an elastic material. The gasket 60 may be formed of rubber or synthetic resin.

The gasket 60 may include: a housing coupler 61 coupled to the periphery of the input hole 12h of the housing 10; a tub coupler 62 coupled to a periphery of the inlet hole of the tub 31; and a tubular extension portion 63 extending from the casing coupler 61 to the tub coupler 62.

The extension portion 63 may include: a flat portion 64 uniformly extending from the casing coupler 61 toward the tub coupler 62; and a foldable portion 65 formed between the flat portion 64 and the tub connector 62.

When the outer tub 31 moves in the eccentric direction, the foldable portion 65 is folded or unfolded. The foldable portion 65 may be formed on a portion of the circumference of the pad 60 or on the entire circumference of the pad 60.

At least one

nozzle

83a or 83b may be installed in the pad 60. The at least one

nozzle

83a or 83b is preferably mounted in the flat portion 64. According to an embodiment, at least one

nozzle

83a or 83b may be integrally formed with the flat portion 64, but aspects of the present invention are not limited thereto, and a nozzle connection structure (not shown) may be formed in the flat portion 64 such that a nozzle inlet pipe (not shown, a pipe through which water pumped by the circulation pump 36 is introduced) formed separately from the gasket 60 is introduced/fixed into the nozzle connection structure. In either case, it is preferable that the outlet of at least one

nozzle

83a or 83b for injecting water into the drum 40 is located in an inner region surrounded by the liner 60, and the circulating water conduit (guide pipe) 18 is connected to an inlet pipe located outside the liner 60.

The periphery of the inlet hole of the front panel 12 is rolled outward, and the housing coupler 61 is fitted into a concave portion formed by the periphery of the rolled portion. An annular groove to be wound by a wire is formed in the housing coupler 61, and the wire is wound on the groove, and then both ends of the wire are joined, so that the housing coupler 61 is firmly fixed to the periphery of the inlet hole of the front panel 12.

A drum 40 in which laundry is accommodated is rotatably provided in the tub 31. A plurality of through holes 47 communicating with the tub 31 may be formed in the drum 40. In addition, a lifter 45 for lifting the laundry while the drum 40 is rotated may be provided on an inner circumferential surface of the drum 40.

The drum 40 is disposed such that the input hole through which the laundry is loaded is located on the front surface, and the drum 40 rotates about a substantially horizontal rotation center line C. In this case, "horizontal" does not refer to its mathematical definition. That is, even in the case where the rotation center line C is inclined at a predetermined angle with respect to the horizontal state, the rotation center line C may be regarded as approximately horizontal if the rotation center line C is more likely to be in the horizontal state than in the vertical state.

The outer tub 31 may be supported by a damper 16 installed at the bottom of the case 10. The vibration of the tub 31 caused by the rotation of the drum 40 may be eliminated by the damper 16.

A water supply hose (not shown) for guiding water supplied from an external water source (e.g., a tap) to the outer tub 31; and a water supply valve 94 for adjusting a water supply hose.

A dispenser 35 for additives (e.g., detergent and fabric softener) supplied to the drum 40 may be provided. The additives may be individually contained in the dispenser 35 according to their types. The dispenser 35 may include a detergent container (not shown) for containing detergent and a softener container (not shown) for containing fabric softener.

At least one water supply pipe 34 may be provided to selectively guide the water supplied through the water supply valve 94 to each receptacle of the dispenser 35. The at least one water supply pipe 34 may include a first water supply pipe for supplying water to the detergent container and a second water supply pipe for supplying water to the fabric softener container, and in this case, the water supply valve 94 may include a first water supply valve for adjusting the first water supply pipe and a second water supply valve 2 for adjusting the second water supply pipe.

Meanwhile, the liner 60 may include a direct water nozzle 57 for injecting water into the drum 40 and a direct water supply pipe 39 for guiding water supplied through the water supply valve 94 to the direct water nozzle 57. The water supply valve 94 may include a third water supply valve for adjusting the direct water supply pipe 39.

The water discharged from the dispenser 35 is supplied to the outer tub 31 through the water supply bellows 37. A water supply hole (not shown) connected to the water supply bellows 37 may be formed in the outer tub 31. A drain hole for draining water may be formed in the outer tub 31, and the drain bellows 17 may be connected to the drain hole. There may be a circulation pump 36 for pumping water discharged from the drain bellows 17 to the circulation water conduit 18.

The circulation pump 36 may include: an impeller (not shown) for pumping water; a pump casing (not shown) for accommodating the impeller; and a circulation pump motor 92 for rotating the impeller. The pump housing may include: an inlet (not shown) through which water is introduced from the drain bellows 17; and a circulating water discharge port (not shown) that discharges water pumped by the impeller to the circulating water conduit 18. An inlet hole of the circulating water conduit 18 is connected to a circulating water discharge port, and an outlet hole of the circulating water conduit is connected to at least one nozzle 83a or nozzle 83b described later.

If a user inputs settings (e.g., washing course, washing time, rinsing time, dehydrating speed, etc.) through an input unit provided on the control panel 14, the controller or processor 91 controls the washing machine to operate according to the inputted settings. For example, algorithms of the water supply valve 94, the washing motor 93, the circulation pump motor 92, the drain valve 96, etc. according to each process selectable through the input unit may be stored in a memory (not shown), and the processor 91 may perform control such that the washing machine operates according to the algorithms corresponding to the settings input through the input unit.

A drain pump 33 may be provided for pumping the water discharged from the pump 31 to the drain pipe 19. The drain pump 33 pumps the water introduced through the drain bellows 17 to the drain pipe 19. The drain pump 33 may include: an impeller (not shown) for pumping water; a pump casing (not shown) for accommodating the impeller; and a drain pump motor 98 for rotating the impeller. The drain pump motor 98 may be configured substantially the same as the circulation pump motor 92. The pump casing may include: an inlet (not shown) into which water is introduced through the discharge bellows 17; and a discharge port (not shown) that discharges the water pumped by the impeller to the drain pipe 19.

Under the control of the processor 91, the circulation pump 38 (e.g., when washing laundry) or the drain pump 33 (e.g., when draining) may be operated according to a preset algorithm.

Meanwhile, the circulation pump motor 92 is a variable speed motor whose rotation speed is controllable. The circulation pump motor 92 may be a brushless direct current motor (BLDC), but the aspect of the present invention is not limited thereto. A driver for controlling the speed of the circulation pump motor 92 may be further provided, and the driver may be an inverter driver. The inverter driver inputs a target frequency to the motor by converting alternating current into direct current.

The circulation pump motor 92 may be controlled by the processor 91. The processor 91 may include a Proportional Integral (PI) controller, a Proportional Integral Derivative (PID) controller, and the like. The controller may receive an output value (e.g., an output current) of the circulation pump motor 92, and control the output value of the driver such that the rotation speed (or the number of rotations) of the circulation pump motor 92 follows a target rotation speed (or the number of rotations) preset based on the output value received by the circulation pump motor 92.

Meanwhile, the processor 91 may control not only the circulation pump motor 92 but also the drain pump motor 98, and may further control the overall operation of the washing machine, and although not specifically mentioned, it should be understood that each component described hereinafter is controlled by the processor 91.

At least one

nozzle

83a and 83b may be provided for spraying the circulating water pumped by the circulating pump 36 into the drum 40. In the embodiment, the

nozzles

83a and 83b disposed at the left and right sides of the liner 60 below the center C of the drum 40 spray water upward, but the scheme of the present invention is not necessarily limited thereto. That is, the number of nozzles and the positions thereof may vary, but in any case, the washing machine according to an embodiment of the present invention preferably includes at least one

nozzle

83a or 83b that further sprays water upward as the pressure of the supplied water increases (i.e., as the discharge pressure, discharge flow rate, rotation speed, or the number of rotations of the circulation pump 36 increases).

The outlet hole of each

nozzle

83a or 83b may be opened upward in the direction of the inside of the drum 40. Therefore, when water of a predetermined pressure or more is supplied, the water sprayed through each

nozzle

83a or 83b may be in a direction inclined toward the inside of the drum 40 such that the sprayed water reaches an area deep inside the drum 40.

Meanwhile, when the pressure of the water supplied to the at least one

nozzle

83a or 83b is insufficient, the water sprayed through the outlet hole of the at least one

nozzle

83a or 83b is not sprayed upward enough and easily drops due to gravity, thereby eventually failing to reach an area deep inside the drum 40.

In fig. 4, the form of the injection water having a sufficient pressure supplied by the circulation pump 36 is denoted by "a", and the form of the injection water having a pressure lower than the sufficient pressure is denoted by "b". That is, as the rotation speed of the circulation pump 36 varies, the form of the water flow injected through at least one

nozzle

83a or 83b may vary between a (high-speed rotation) and b (low-speed rotation).

Fig. 5 schematically shows a front view of the drum, in which the spray range of each nozzle is shown. Fig. 6 schematically shows a side view of the drum, in which the spray range of each nozzle is shown.

Referring to fig. 5, quadrants Q1, Q2, Q3, and Q4 are defined by dividing the drum 40 into four when viewed from the front side of the drum. The first nozzle 83a is disposed in the third quadrant Q3, and the second nozzle 83b is disposed in the fourth quadrant Q4. In fig. 5, the lower limit b of the water flow jetted through each of the

nozzles

83a and 83b represents a case where the circulation pump motor 92 rotates at 2600rpm, and the upper limit a of the water flow jetted through each of the

nozzles

83a and 83b represents a case where the circulation pump motor 92 rotates at 3000 rpm.

The first nozzle 83a is used to spray water to an area ranging from the third quadrant Q3 to the second quadrant Q2 according to the rotation speed of the circulation pump motor 92. That is, as the rotation speed of the circulation pump motor 92 increases, the water is gradually sprayed further upward through the first nozzles 83a, and if the circulation pump motor 92 rotates at the highest speed, the water flow sprayed from the first nozzles 83a reaches the second quadrants Q2 of the rear surface 41 of the drum 40.

The second nozzle 83b is used to spray water to the area within the range of the fourth quadrant Q4 and the first quadrant Q2 according to the rotation speed of the circulation pump motor 92. That is, as the rotation speed of the circulation pump motor 92 increases, the water is gradually sprayed further upward through the second nozzles 83b, and if the circulation pump motor 92 rotates at the highest speed, the water flow sprayed from the second nozzles 83b reaches the first quadrants Q2 on the rear surface 41 of the drum 40.

Referring to fig. 6, the first, second and third regions are defined as three divisional regions of the drum 400 when viewed from the side of the drum. As the rotation speed of the circulation pump motor 92 is gradually increased, the water stream sprayed from at least one of the

nozzles

83a or 83b reaches a deeper area inside the drum 40. As shown in the example of the drawing, if the rotation speed of the circulating rotation pump motor 92 is 2200rpm, the water current sprayed from the at least one nozzle 83a or nozzle 83b reaches the first region (0-1/3L) on the inner circumferential surface 42 of the drum 40, if the rotation speed of the circulating pump motor 92 is 2500rpm, the water current sprayed from the at least one nozzle 83a or nozzle 83b reaches the second region (1/3L-2/3L), and if the rotation speed of the circulating pump motor 92 is 2800rpm, the water current sprayed from the at least one nozzle 83a or nozzle 83b reaches the third region (2/3L-L). If the rotation speed of the circulation pump motor 92 is further increased, the water flow may reach the rear surface 41 of the drum 40. If the rotation speed is 300rpm, the water current reaches one third of the height H of the drum 40; if the rotation speed is 3400rpm, the water current reaches two thirds of the height H of the drum 40; if the rotation speed is 3400rpm, the water flow reaches the maximum height available, and due to the structure of at least one

nozzle

83a or 83b, the water flow cannot go further upward after reaching the maximum height available, eventually resulting in only increasing the strength of the water flow.

Fig. 7 is a diagram illustrating a drum driving action that may be implemented by the washing machine according to the embodiment of the present invention. Hereinafter, the drum driving action will be described in detail with reference to fig. 7.

The drum driving action refers to a combination of the rotational direction and the rotational speed of the drum 40. The falling direction and the falling time of the laundry received in the drum 40 may be changed according to the drum driving motion, and thus the movement of the laundry in the drum 40 may be changed. The drum driving action may be achieved by the processor 91 controlling the washing motor 93.

Since the laundry is lifted by the lifters 45 provided on the inner circumferential surface of the drum 40 when the drum 40 rotates, it is possible to vary the impact force applied to the laundry by controlling the rotation speed and the rotation direction of the drum 40. That is, mechanical forces such as a frictional force between the laundry, a frictional force between the laundry and the washing water, and a falling impact of the laundry may be changed. In other words, the degree of impact (hitting) or rubbing (rubbing) of the laundry for washing may be changed, and the degree of scattering or inversion (turning up) of the laundry may be changed.

Meanwhile, in order to realize these various drum driving actions, it is preferable that the washing motor 93 be a direct drive motor. That is, a configuration of the motor is preferable in which a stator of the motor is fixedly secured to a rear portion of the outer tub 31, and the driving shaft 38 rotating together with a rotor of the motor directly drives the drum 40. This is because the direct drive motor helps to control the rotational direction and torque of the motor so that the drum driving action can be rapidly controlled without a delay time or backlash (backlash).

However, if the washing machine has a structure in which torque from the motor is transmitted to the driving shaft through a pulley or the like, drum driving actions (e.g., drum driving action, spin-drying action, etc.) regardless of delay time or play can be realized, but the structure is not suitable for realizing other various drum driving actions. A method for driving the washing motor 93 and the drum 40 is apparent to those skilled in the art, and thus a detailed description thereof is omitted herein.

In fig. 7, (a) is a diagram showing a kneading action. The rubbing action is an action in which the washing motor 93 rotates the drum 40 in one direction (preferably, one or more times), and drops the laundry on the inner circumferential surface of the drum 40 from a position at an angle of less than 90 degrees in the rotation direction (rotation) of the drum 40. In this case, the laundry drops to the lowest position of the drum 40.

For example, if the washing motor 93 rotates the drum 40 at about 40rpm, the laundry at the lowest position in the drum 40 is lifted to a predetermined height in the rotation direction of the drum 40 and dropped from a predetermined position spaced less than 90 degrees from the lowest position in the drum 40 in the rotation direction to the lowest position in the drum 40 as if the laundry were rolling. When the drum 40 rotates in the clockwise direction, it seems as if the laundry keeps rolling at the third quadrant 3Q of the drum 40.

In the rubbing action, the laundry is washed by friction with the washing water, friction between the laundry, and friction with the inner circumferential surface of the drum 40. In this case, the motion causes the laundry to be sufficiently inverted, thereby providing an effect of lightly rubbing the laundry.

Here, it is preferable that the rotation speed rpm of the drum 40 is determined with respect to the radius of the drum 40. That is, the greater the RPM of the drum 40, the stronger the centrifugal force acting on the laundry in the drum 40. The difference between the centrifugal force and the gravity force makes the movement of the laundry different. Of course, the rotation force of the drum 40, the friction between the drum 40 and the laundry, and the RPM of the drum 40 should also be considered. The rotation speed of the drum 40 in the kneading motion is determined such that the sum of various forces (e.g., frictional force and centrifugal force) applied to the laundry is weaker than gravity by 1G.

In fig. 7, (b) is a diagram showing the tumbling motion. The tumbling motion is a motion in which the washing motor 93 rotates the drum 40 in one direction (preferably, one or more times), and drops the laundry on the inner circumferential surface of the drum 40 from a position of about 90 degrees to 110 degrees in the rotation direction (rotation) of the drum 40 to a lowest position in the drum 40. The tumbling motion is a drum driving motion generally used in washing and rinsing because a mechanical force is generated only when the control drum 40 is rotated at an appropriate rotation speed in one direction.

Before the motor 140 is driven, the laundry loaded into the drum 40 is located at the lowest position in the drum 40. When the washing motor 93 provides torque to the drum 40, the drum 40 rotates, so that the lifters 45 provided on the inner circumferential surface of the drum 40 lift the laundry from the lowest position in the drum 40. For example, if the washing motor 93 rotates the drum 40 at about 46rpm, the laundry drops from a position at about 90 to 110 degrees from a lower position of the drum 40 in the rotation direction.

In the tumbling motion, the rotation speed of the drum 40 may be determined such that the tumbling motion generates a centrifugal force stronger than the centrifugal force of the kneading motion but weaker than the gravity.

The tumbling motion is exhibited such that the laundry is lifted from the lowest position in the drum 40 to a position at 90 degrees from the lowest position or up to the second quadrant Q2, and drops therefrom as being separated from the inner circumferential surface of the drum 40.

Therefore, in the tumbling motion, the laundry is washed by friction of the laundry with the washing water and impact caused by dropping of the laundry, especially by a mechanical force stronger than that generated in the kneading motion. In particular, the tumbling motion has the effect of disentangling and scattering the laundry.

In fig. 7, (c) is a diagram showing the beat-wash operation. The beat-wash action is a motion in which the motor 140 rotates the drum 40 in one direction (preferably, completes one rotation) and drops the laundry on the inner circumferential surface of the drum 40 from the uppermost position of the drum 40 (preferably, a position of about 146 degrees to 161 degrees from the lowermost position in the drum 40, but not limited thereto, or a position in which the drum 40 is rotated more than 161 degrees but less than 180 degrees (e.g., rotated 180 degrees)).

That is, the beat-wash motion is a motion in which the drum 40 is rotated at a speed at which the laundry is prevented from falling off from the inner circumferential surface of the drum 40 due to the centrifugal force (i.e., a speed at which the laundry is rotated together with the drum 40 while being adsorbed to the inner circumferential surface of the drum 40 due to the centrifugal force), and the drum 40 is suddenly braked, thereby maximizing the impact on the laundry.

For example, if the washing motor 93 rotates the drum 40 at a speed exceeding about 60rpm, the laundry may be rotated by centrifugal force without falling (i.e., rotated together with the drum 40 while being adsorbed to the inner circumferential surface of the drum 40), and, in the process, if the laundry is lifted up to a predetermined height by the rotation of the drum 40, it is possible to control a torque in a direction opposite to the rotation direction of the drum 40 to be applied to the washing motor 93.

In the beat-wash motion, the laundry is lifted from the lowest position of the drum 40 to the highest position by the rotation of the drum 40 and then is suddenly dropped due to the braking of the drum 40, compared to other motions, thereby maximizing the drop impact to the laundry. Thus, the mechanical force (e.g., impact force) generated by the slapping action is typically stronger than the mechanical force generated by the kneading or tumbling action.

The beating motion is exhibited such that, when the drum 40 rotates in the clockwise direction, the laundry moves from the lowest position in the drum 40 to a predetermined height (e.g., the highest position (180 degrees) of the drum 40) via the third quadrant 3Q and the second quadrant 2Q, and then suddenly separates from the inner circumferential surface of the drum 40, falling to the lowest position in the drum 40. Therefore, when the amount of laundry is small, the beating motion may more effectively provide mechanical force to the laundry.

Meanwhile, in order to brake the drum 40 by the motor 140 in the beat-wash operation, it is preferable to perform reverse braking. The reverse phase braking is a motor braking method in which a rotational force is generated in a direction opposite to a current rotational direction of the washing motor 93 to brake the washing motor 93. In order to generate a rotational force in a direction opposite to the current rotational direction of the washing motor 93, the phase of the current supplied to the washing motor 93 may be reversed, and thus sudden braking is performed in this manner.

The beat-wash action is an action in which, when the drum 40 is rotated, laundry is washed by friction between the drum 40 and the laundry, and when the drum 40 is braked, the laundry is washed by dropping of the laundry and an impact of inverting the laundry.

In fig. 7, (d) is a diagram showing a shaking motion. The shaking motion is a motion in which the washing motor 93 bi-directionally rotates the drum 40 and drops the laundry from a position of about less than 90 degrees (preferably, a position of about 30 to 45 degrees rotated in the rotation direction of the drum 40), but is not limited thereto, and may be a position of more than 45 and less than 90 degrees rotated in the rotation direction of the drum 40. For example, if the washing motor 93 rotates the drum 40 at about 40rpm in a counterclockwise direction, the laundry at the lowermost position in the drum 40 is lifted to a predetermined height in the counterclockwise direction. In this case, the washing motor 93 stops the rotation of the drum 40 before the laundry reaches a position rotated about 90 degrees in the counterclockwise direction, so that the laundry falls from a position rotated about less than 90 degrees in the counterclockwise direction (rotation) to a lowermost position in the drum 40.

After the rotation of the drum 40 is stopped, the washing motor 93 rotates the drum 40 in a clockwise direction at about 40rpm, thereby lifting the laundry to a predetermined height in the rotation direction of the drum 40 (i.e., clockwise direction). Then, before the laundry reaches a position of about 90 degrees in the clockwise direction, the washing motor 93 is controlled to stop rotating the drum 40, so that the laundry drops or rolls from a position of about less than 90 degrees to a lowest position in the drum 40.

That is, the swing motion is a motion of repeating forward rotation and stop of the drum 40 and backward rotation and stop of the drum 40, and it appears that the laundry repeats a motion in which the laundry is lifted from the lowest position to the second quadrant 2Q of the drum 40 via the third quadrant 3Q and softly dropped therefrom, and then the laundry is lifted to the first quadrant 1Q via the fourth quadrant 4Q of the drum 40 and softly dropped therefrom. That is, the shaking motion is exhibited such that the laundry makes a motion of looking like a lying down character 8 on the third and fourth quadrants 3Q and Q4 of the drum 40.

In this case, a resistance braking (rheostatic braking) is sufficient to brake the washing motor 93. The resistance braking can minimize the load on the washing motor 93 and the mechanical wear of the washing motor and control the impact applied to the laundry.

The resistance braking is a braking method that utilizes a generator-like function of the washing motor 93 due to rotational inertia thereof when cutting off the current flowing to the motor. If the current flowing to the motor is cut off, the direction of the current flowing to the coil of the washing motor 93 is opposite to the direction of the current before the power is cut off, so a force (fleming's right hand rule) acts in a direction to interfere with the rotation of the washing motor 93, thereby braking the washing motor 93. Unlike the reverse phase braking, the resistance braking does not abruptly brake the washing motor 93 but smoothly changes the rotation direction of the drum 40.

In fig. 7, (e) is a diagram showing the scrub action. The scrubbing motion is a motion in which the washing motor 93 rotates the drum 40 bidirectionally and drops the laundry from more than about 90 degrees in the rotation direction of the drum 40.

For example, if the washing motor 93 rotates the drum 40 in a forward direction at a speed of about 60rpm or more, the laundry is lifted to a predetermined height in the forward direction from the lowest position of the drum 40. In this case, when the laundry reaches a position corresponding to a set angle of about 90 degrees or more (preferably, but not limited to, an angle of 139 to 150 degrees, and may be 150 degrees or more) in the forward direction, the washing motor 93 provides a reverse torque to the drum 40, thereby temporarily stopping the rotation of the drum 40. Then, the laundry adsorbed to the inner circumferential surface of the drum 40 is abruptly dropped.

Then, the washing motor 93 rotates the drum 40 in a backward direction at a speed of about 60RPM or more, thereby lifting the falling laundry to a predetermined height of 90 degrees or more in the backward direction. When the laundry reaches a position corresponding to a set angle of 90 degrees or more (e.g., an angle of 139 to 150 degrees) in the backward direction, the washing motor 93 provides a reverse torque to the drum 40 again, thereby temporarily stopping the rotation of the drum 40. In this case, the laundry adsorbed to the inner circumferential surface of the drum 40 falls from a position of 90 degrees or more in the backward direction.

The scrubbing motion can wash the laundry by abruptly dropping the laundry from a predetermined height. In this case, it is preferable that the washing motor 93 is braked in reverse-phase (reverse-phase) to brake the drum 40.

Since the rotation direction of the drum 40 is abruptly changed, the laundry is not separated from the inner circumferential surface of the drum 40 to a large extent, and thus, the scrubbing motion may have a strong rubbing effect of the washing.

For example, the scrubbing motion is a repetitive motion in which the laundry moves to the second quadrant via the third quadrant, drops abruptly therefrom, moves to the first quadrant via the fourth quadrant, and drops abruptly therefrom. Thus, the scrubbing motion appears to the laundry to move up and down repeatedly.

In fig. 7, (f) is a diagram showing a filtering action. The filtering action is an action in which the washing motor 93 rotates the drum 40 while preventing the laundry from being separated from the inner circumferential surface of the drum 40, while the washing water is sprayed to the inside of the drum 40 through at least one

nozzle

83a or 83 b.

Since the washing water is sprayed to the inside of the drum 40 while the laundry is dispersed and rotated in close contact with the inner circumferential surface of the drum 40, the washing water penetrates into the laundry due to centrifugal force and is then discharged to the tub 31 through the through holes 47 of the drum 40.

Since the filtering action allows the washing water to permeate into the laundry while expanding the surface area of the laundry, the laundry is uniformly soaked.

In fig. 7, (g) is a diagram showing the pressing action. The squeezing motion is a motion in which the washing motor 93 repeats an operation of rotating the drum 40 so that the laundry does not fall off from the inner circumferential surface of the drum 40, and the rotation speed of the drum 40 is reduced so that the laundry is separated from the inner circumferential surface of the drum 40 when the washing water is sprayed into the drum 40 through the at least one

nozzle

83a or 83 b.

That is, the squeezing action is different from the filtering action in that the laundry is rotated at a speed at which the laundry is not separated from the inner circumferential surface of the drum 40, and in the squeezing action, the drum 40 repeats acceleration and deceleration of the drum so that adsorption to and separation from the inner circumferential surface are repeated.

Fig. 8 is a graph for comparing washing performance and vibration level between various drum driving motions. In fig. 8, the horizontal axis represents washing performance, and contaminants contained in laundry may be more easily separated toward the left direction of the horizontal axis. The vertical axis represents a vibration level and a noise level, and the vibration level increases in an upward direction toward the vertical axis while the time required to wash the same laundry decreases in the upward direction toward the vertical axis.

The beating and scrubbing motions are motions suitable for a washing course selected when laundry is heavily contaminated and a reduction in washing time is required. Furthermore, the beat and scrub actions are actions that result in a high degree of vibration and a high noise level. Therefore, the beating and rubbing motions are not preferred motions for washing courses selected when the laundry is sensitive clothes or noise and vibration need to be minimized.

The kneading motion is a motion characterized by excellent washing performance, low vibration level, minimized possibility of damaging laundry, and low motor load. Therefore, the kneading action is suitable for each washing course, and is particularly suitable for dissolving the detergent and soaking the laundry in the initial washing stage. However, the rubbing motion generates a lower vibration level than the tumbling motion, but takes a longer time to wash the laundry to a certain level.

The washing performance of the tumbling action is lower than that of the scrubbing action, but the degree of vibration thereof is between the degree of vibration of the scrubbing action and the degree of vibration of the scrubbing action. The tumbling action is suitable for each washing process, and is particularly suitable for the step of dispersing the laundry.

The washing performance of the pressing motion is similar to that of the tumbling motion, and the vibration level thereof is higher than that of the tumbling motion. In the squeezing motion, the washing water permeates into the laundry and is discharged to the outside of the drum 40 in a process in which the laundry is repeatedly adsorbed to and separated from the inner circumferential surface of the drum 40, and thus, the squeezing motion is suitable for a rinsing step or a step of supplying the washing water to the laundry.

The washing performance of the filtering action is lower than that of the squeezing action, and the noise level thereof is similar to that of the kneading action. In the filtering action, the washing water permeates the laundry and is discharged to the outer tub 31 while the laundry is adsorbed to the inner circumferential surface of the drum 40, and thus, the filtering action is suitable for a step of soaking the laundry or a step of supplying the washing water to the laundry at an initial washing stage.

The shaking motion is the motion with the lowest vibration level and the lowest washing performance. The shaking motion is therefore suitable for washing processes with low noise or low vibration and for gentle care (step) meaning that sensitive clothes are to be washed.

Fig. 9 is a diagram for explaining the ejection operation in each of the drum driving operations of the present invention, compared with the conventional operation. In fig. 9, (a) is a graph showing the rotation speed of the drum 40 or the washing motor 93 in each drum driving action, (b) is a graph showing the rotation speed of the circulation pump motor in the existing washing machine having the constant speed pump in each drum driving action, (c) is a graph showing the rotation speed of the circulation pump motor 92 in the washing machine according to the embodiment of the present invention in each drum driving action, and (e) shows the spray pattern through at least one

nozzle

83a or 83b (hereinafter, referred to as "spray action") in each drum driving action in the washing machine according to the embodiment of the present invention.

Referring to fig. 9, since the conventional washing machine cannot change the speed of the circulation pump motor, the conventional washing machine has no choice but to rotate the circulation pump motor at a constant speed all the time even if the drum driving motion is changed. Therefore, the existing washing machine cannot effectively respond to the movement of the laundry according to the type of drum driving action by using the water stream sprayed through the nozzle, and has difficulties in managing power consumption, washing performance, and soaking the laundry. The present invention aims to solve these problems by appropriately controlling the rotation speed of the circulation pump motor 92 in accordance with the drum driving action and in the process in consideration of the laundry load.

In particular, in the case of a drum driving action in which laundry is lifted while being adsorbed to the inner circumferential surface 42 of the drum 40 and is separated from the inner circumferential surface 42 due to braking of the drum when a predetermined height is reached, thereby falling from the inner circumferential surface (hereinafter, referred to as a "drop triggering action by braking" (e.g., a shaking action, a beating action, or a scrubbing action)), the rotation speed of the circulation pump motor 92 may be controlled to be varied within a predetermined speed range. That is, the circulation pump motor 92 may be controlled to repeat the operation of accelerating to the upper limit of the speed range and decelerating to the lower limit of the speed range.

The range in which the rotation speed of the circulation pump motor 92 changes while the drop trigger action by braking (effecting) is performed may be set according to the laundry load.

In a region where the circulation pump motor 92 is controlled to rotate at a constant speed in the kneading motion, the tumbling motion, and the filtering motion, the rotation speed of the circulation pump motor 92 may be set according to the laundry load.

Meanwhile, referring to (c) of fig. 9, the RPM of the circulation pump motor 92 may be controlled in different manners in the rubbing action, the shaking action, the patting action, the scrubbing action, and the filtering action. In the figure, the RPM of the circulation pump motor 92 in response to a large laundry load is indicated by a solid line, and the RPM of the circulation pump motor 92 in response to a small laundry load is indicated by a dotted line. In the case of the tumbling action, the RPM of the circulation pump motor 92 may be controlled in the same manner regardless of the laundry load.

In each drum driving action shown in fig. 9, the operation of the washing motor 93 and the operation of the circulation pump motor 92 are correlated with each other. Hereinafter, a method for controlling the washing motor 92 and the circulation pump motor 92 will be described with reference to fig. 10. In fig. 9, a1 to a6 show steps of controlling the washing motor 93, and B1 to B6 show steps of controlling the circulation pump motor 92.

When the washing machine is operated, if a preset drum driving motion is started, the processor 91 controls the washing motor 93 and the circulation pump motor 92 according to a method set for each drum driving motion.

Specifically, the processor 91 starts the driving of the washing motor 93 (a1), and accelerates the washing motor 93 (a 2). A sensor for sensing a rotation angle of the drum 40 may be provided, and if the rotation angle of the drum 40 sensed by the sensor reaches a predetermined value θ (hereinafter, referred to as "action angle") (A3), the processor 91 may perform control to decelerate the washing motor 93 (a 4).

The drum 40 may be continuously rotated one or more times in the kneading motion, the tumbling motion, and the filtering motion, and in this case, the motion angle θ is 360 degrees or more.

In contrast, in the drop trigger action by braking (realization), such as the shake action, the beat action, and the scrub action, the action angle θ may be set to an appropriate value within a range of 180 degrees according to the characteristics of each corresponding drum driving action. For example, the motion angle θ may be 30 degrees to 45 degrees in the shaking motion, 146 degrees to 161 degrees in the shaking motion, and 139 degrees to 150 degrees in the scrubbing motion.

When the drum 40 is decelerated to stop, the drum driving action is completed once, and then the drum driving action is performed again (a 5). The steps a2 to a5 are repeatedly performed until the number of times of performing the drum driving motion reaches a preset number of times, and when the number of times of performing the drum driving motion reaches the preset number of times, the operation of the washing motor 93 is stopped (a 6).

Meanwhile, when the driving of the washing motor 93 is started in step a1, the processor 91 applies a start signal SG1 to the circulation pump motor 92, and starts the driving of the circulation pump motor 92 in response to the start signal SG1 (B1). Then, based on the motion information (i.e., information on the drum driving motion currently being performed), the processor 91 accelerates the circulation pump motor 92 according to the setting set for each drum driving motion (B2).

Meanwhile, in step S3, when the rotation angle of the drum 40 reaches the action angle θ, the processor 91 applies an angle control completion signal SG2 to the circulation pump motor 92.

In the case of the drop trigger action by braking (effecting), in response to the angle control completion signal SG2, after the rotation speed reaches the upper limit value Pr (V, H) set for each drum driving action, the rotation speed stops accelerating (or the circulation pump motor 92 is braked), and then the rotation speed is decelerated in accordance with the setting set for each drum driving action (B4, B5).

Then, when the driving of the washing motor 92 is started again in step a5, the processor 91 applies a restart signal SG3 to the circulation pump motor 92. In response to the restart signal SG3, the circulation pump motor 92 stops decelerating the rotation speed when the rotation speed reaches the lower limit value Pr (V, L) set for each drum driving action (B5), and steps B2 to B5 are repeated.

Meanwhile, in the case of the rubbing action, the tumbling action, or the filtering action, while the angle control completion signal SG2 is applied to the circulation pump motor 92, the circulation pump motor 92 is rotated while maintaining the rotation speed set for each corresponding drum driving action. Therefore, in the above-described operation, the circulation pump motor 92 is decelerated in response to the angle control completion signal SG2 (B4).

Meanwhile, in any drum driving motion, when the washing motor 93 is stopped in step a6, the processor 91 applies a stop signal SG4 to the circulation pump motor 92, and the circulation pump motor 92 is stopped in response to the stop signal SG 4.

As shown in fig. 11, the washing machine may be configured to sequentially implement a water supply/laundry soaking cycle, a washing cycle, a dehydrating cycle, a rinsing cycle, and a dehydrating cycle. The water supply/laundry soaking cycle is a cycle for soaking laundry by supplying water with detergent.

The washing cycle is a cycle for removing contaminants from the laundry by rotating the drum 40 according to a predetermined algorithm, and a kneading motion or a tumbling motion may be performed during the washing cycle.

The dehydration cycle is a cycle for removing moisture from laundry by rotating the drum 40 at a high speed. The drain pump 33 may be operated while the drum 40 is rotated.

The rinsing cycle is a cycle for removing detergent from laundry. During the rinsing cycle, water is supplied and a kneading motion or a tumbling motion may be performed. After the rinsing cycle, the dehydrating cycle may be performed again.

Hereinafter, a method for controlling the washing motor 93 and the circulation pump motor 92 in each drum driving action will be described in more detail.

Fig. 12 shows a graph of the speed (a) of the washing motor in the kneading motion and the tumbling motion, and a graph of the speed (b) of the circulation pump motor in the kneading motion and the tumbling motion. Fig. 16 is a graph comparing between when the laundry load falls within the first laundry load range I and when the laundry load falls within the second laundry load range II.

The washing machine may perform a first step of rotating the drum 40 in one direction such that the laundry on the inner circumferential surface of the drum 40 is lifted to a position corresponding to a rotation angle of the drum 40 of approximately less than 90 degrees and dropped therefrom, and perform a second step of rotating the drum 40 in one direction such that the laundry on the inner circumferential surface of the drum 40 is lifted to a position higher than a position corresponding to a rotation angle of the drum 40 of less than 130 degrees and then dropped therefrom. The second step may be performed after the first step, but the aspect of the present invention is not limited thereto, and the second step may be performed before the first step.

The number of revolutions of the circulation pump 36 during the first step may be controlled to a preset first revolution value, and the number of revolutions of the circulation pump 36 during the second step may be controlled to a second revolution value higher than the first revolution value. Here, the first rotation value and the second rotation value are values during which the circulation pump 36 is rotated at a constant speed.

The driving action of the drum in the first step (i.e., the drum driving action) may correspond to the kneading action. The drum driving motion in the second step may be a kneading motion or a tumbling motion, and preferably may be a tumbling motion. Hereinafter, an example of performing the kneading action in the first step and the tumbling action in the second step is described.

Referring to fig. 12 to 16, the kneading motion and the tumbling motion are performed using the water contained in the outer tub 31 so that the water current may be sprayed through at least one nozzle 83a or nozzle 83 b. Referring to fig. 12, in the kneading action, drum 40 is accelerated to rotation speed dr (r) and rotated while maintaining rotation speed dr (r) for a predetermined time. The rotation speed Dr (R) is preferably 37rpm to 40rpm, but is not necessarily limited thereto.

During the kneading action, the rotation speed of the circulation pump motor 92 is controlled to a preset rotation speed pr (r). In fig. 12, t (SG1) indicates the timing at which the start signal SG1 (see fig. 10) is generated, t (SG2) indicates the timing at which the angle control completion signal SG2 (see fig. 10) is generated, and t (SG4) is the timing at which the stop signal SG4 (see fig. 10) is generated. In the following, the same indication is used in other examples.

The rotation speed pr (r) may be set according to the laundry load. Before performing the drum driving action, the processor 91 may rotate the washing motor 93 and sense the laundry load while rotating the washing motor 93. The laundry load may be determined based on the principle that the moment of inertia of the drum 40 varies according to the laundry load received in the drum 40. For example, the laundry load may be calculated by measuring a time taken to reach a preset target speed, by measuring an acceleration slope of the washing motor 93, by measuring a time taken to stop the washing motor 93 in braking the washing motor 93, by measuring a deceleration gradient, or by measuring a counter electromotive force. The aspect of the present invention is not limited thereto, and various methods of calculating a laundry load have been well known in the related art of washing machines, and thus the well-known methods may be applied. Hereinafter, although not described, it is assumed that the step of sensing laundry loading is performed before each drum driving motion is performed.

The processor 91 may set the rotation speed pr (r) according to a laundry load range in which the sensed laundry load falls. For example, the laundry loads may be classified into first to ninth categories. In the case of classifying the laundry load range into a light load (or a first laundry load range I; see fig. 16) and a heavy load (or a second laundry load range II; see fig. 16), the sensed laundry load may be classified as a light load if it corresponds to the first to fourth categories, and as a heavy load if it corresponds to the fifth to ninth categories. However, aspects of the present invention are not limited thereto, and the laundry load range may be divided for each category.

In this embodiment, when the laundry load is heavy, the rotation speed (rotation) is set higher than that when the laundry load is light. For example, if the laundry load is light, the rotation speed pr (r) may be set to 2800rpm, and if the laundry load is heavy, the rotation speed pr (r) may be set to 3100 rpm. In particular, when the load of laundry is light, most of the laundry moves in the front portion of the drum 40, and therefore the water stream sprayed from at least one

nozzle

83a or 83b does not have to reach the rear surface 41 of the drum (rotation speed less than 2800 rpm; see fig. 6).

In contrast, when the load of laundry is heavy, the laundry is loaded to the center of the drum 40, and thus the water stream sprayed from at least one

nozzle

83a or 83b needs to reach a height higher than the center of the drum 40. Therefore, it is preferable that the water flow reaches the first quadrant Q1 (see fig. 5) and the second quadrant Q2 (see fig. 5), and for this reason, the rotation speed of the circulation pump motor 92 is set to 3000rpm or more, preferably 3100 rpm.

In the tumbling action, the washing motor 93 and the circulation pump motor 92 are controlled in a manner similar to that in the kneading action. However, for the same laundry load, the rotation speed dr (r) of the washing motor 93 during the tumbling motion is set higher than the rotation speed during the kneading motion, and the rotation speed pr (t) of the circulation pump motor 92 during the tumbling motion is also set higher than the rotation speed during the kneading motion. Meanwhile, the rotation speed dr (t) of the washing motor 93 is preferably 46rpm, but is not necessarily limited thereto.

Meanwhile, in the tumbling motion, it is important to apply a stronger mechanical force to the laundry than in the kneading motion, and therefore, the water stream sprayed through the at least one

nozzle

83a or 83b needs to have a sufficient pressure regardless of the laundry load. Therefore, in the tumbling motion, the circulation pump motor 92 may be rotated at a constant speed of a predetermined value between 3400rpm and 3600rpm regardless of the load of the laundry. However, the aspect of the invention is not limited to this, and when the laundry load is heavy, the rotation speed pr (t) may be set higher than that when the laundry load is light. For example, when the laundry load is light, the rotation speed pr (t) may be set to 3400rpm, and when the laundry load is heavy, the rotation speed pr (t) may be set to 3600 rpm.

The step of controlling the circulation pump 36 while performing the above-described kneading motion and tumbling motion is suitable for the washing cycle and/or the rinsing cycle in the series of cycles shown in fig. 11.

Fig. 13 is a graph for explaining how the washing motor and the circulation pump motor operate in the shaking motion, the scrubbing motion, and the beating motion according to the embodiment of the present invention.

Referring to fig. 13 and 16, in the drop trigger action by braking (effecting), the processor 91 performs control such that the rotation speed of the circulation pump motor 92 is changed while the drum 40 is rotating.

The drop trigger action by braking (effecting) is performed by the outer tub 31 filled with water, so that the water flow is sprayed through the nozzle 83a or the nozzle 83 b. In the drop trigger action by braking (effecting), the processor 91 may accelerate the washing motor 93 so that the laundry on the inner circumferential surface 42 of the drum 40 is lifted while being adsorbed to the drum 40. At the speed of accelerating the washing motor 93 so that the drum 40 rotates the shaft at a speed at which the laundry is lifted without falling from the inner circumferential surface of the drum 40, the processor 91 brakes the washing motor 93 so that the laundry falls from the inner circumferential surface 42. That is, in the falling trigger action by the braking (realization), the washing motor 93 accelerated to the preset rotation speed dr (v) is decelerated to stop.

The rotational speed dr (v) may be set differently for each drum driving action. The maximum laundry lifting height is increased in the order of the shaking motion, the scrubbing motion, and the patting motion, and thus, the magnitude of the centrifugal force should be increased in the order of the shaking motion, the scrubbing motion, and the patting motion. Therefore, the rotation speed dr (v) can be set to increase in the order of the shake, scrub, and beat motion.

However, the maximum laundry lifting height in the drop trigger motion by braking (realization) is also determined by the rotation angle (or motion angle θ) of the brake drum 40, and therefore, even in the case where the same rotation speed dr (v) is set for all of the shaking motion, the rubbing motion, and the beating motion, if a different motion angle θ is set for each motion, the maximum laundry lifting height (or the height at which laundry starts to drop) may be different. In either case, it is preferable that the action angle θ is set to increase in the order of the shake action, the scrub action, and the beat action. Within the range satisfying the above-mentioned premise, the motion angle θ may be set to, for example, 30 to 45 degrees for the shake motion, 139 to 150 degrees for the scrub motion, and 146 to 161 degrees for the beat motion.

Meanwhile, during the drop trigger action by braking (effecting), the processor 91 may increase the rotation speed of the circulation motor 92 when the laundry is lifted (or when the washing motor 93 is accelerated).

During the drop trigger action by braking (effecting), the processor 91 may decelerate the rotation speed of the circulation pump motor 92 when the laundry is dropped (or when the washing motor 93 is braked to be decelerated).

That is, the processor 91 may control the circulation pump motor 92 such that the circulation pump motor 92 is accelerated in response to acceleration of the washing motor 93, and is decelerated in response to braking of the washing motor 93.

The rotation speed of the circulation pump motor 92 may be varied within a rotation speed range set for each drum driving action. In fig. 13, the upper limit value of the rotation speed range is represented as the maximum rotation speed Pr (V, H), and the lower limit value thereof is represented as the minimum rotation speed Pr (V, L).

Hereinafter, the maximum rotation speed of the circulation pump motor 92 is taken as the upper limit of the preset rotation speed range. The maximum rotational speed of the circulation pump motor 92 does not refer to the maximum speed at which the circulation pump 92 can rotate.

Before performing the drum driving action, the processor 91 may rotate the washing motor 93 and sense the laundry load while rotating the washing motor 93. The method for sensing the load of laundry may be implemented as described above in relation to the tumbling action/tumbling action, or may be implemented using any other method.

The rotation speed range may be set according to the laundry load. That is, the processor 91 may set the maximum rotation speed Pr (V, H) and the minimum rotation speed Pr (V, L) according to the laundry load. In each drum driving action, the rotation speed range may be set higher as the laundry load increases.

For example, in the case of the scrub motion SC, when the sensed laundry load corresponds to a light load (or a first laundry load range I; see FIG. 16), the rotation speed of the circulation pump motor 92 may vary between a lowest rotation speed Pr (V, L) of 2800prm and a highest rotation speed Pr (V, H) of 3100 rpm. Further, when the sensed laundry load corresponds to a heavy load (or a second laundry load range II; see FIG. 16), the rotation speed of the circulation pump motor 92 may be varied between the lowest rotation speed Pr (V, L) of 3400rpm and the highest rotation speed Pr (V, H) of 3600 rpm.

In the case of the beat-wash action ST, when the sensed laundry load corresponds to a light load (or the first laundry load range I; see fig. 16), the rotation speed of the circulation pump motor 92 may vary between the lowest rotation speed Pr (V, L) of 2200prm and the highest rotation speed Pr (V, H) of 2500 rpm. Further, when the sensed laundry load corresponds to a heavy load (or a second laundry load range II; see FIG. 16), the rotation speed of the circulation pump motor 92 may be varied between the lowest rotation speed Pr (V, L) of 3400rpm and the highest rotation speed Pr (V, H) of 3600 rpm.

Meanwhile, even in the case of the shaking motion SW, the range in which the rotation speed of the circulation pump motor 92 varies according to the laundry load may be set in a similar manner to the scrubbing motion SC or the beating motion ST.

In this case, it is preferable to set the rotation speed of the circulation pump motor 92 within a range that does not allow the water stream sprayed from the at least one

nozzle

83a or 83b to reach the rear surface 41 of the drum 40 (e.g., 2200rpm to 2800 rpm; see fig. 6).

However, since the height at which the laundry falls in the shaking motion is smaller than the height at which the laundry falls in the scrubbing motion or the beating motion, the predetermined rotation speed range of the circulation pump motor 92 can be set regardless of the load of the laundry. For example, the rotation speed of the circulation pump motor 92 may vary between a minimum rotation speed Pr (V, L) of 2200rpm and a maximum rotation speed Pr (V, H) of 2800rpm both in the case of heavy laundry loads and in the case of light laundry loads.

Hereinafter, operations of the washing motor and the circulation pump motor in the shaking motion, the scrubbing motion, and the patting motion according to an embodiment of the present invention will be described in more detail with reference to fig. 10, 13, and 16.

Referring to fig. 10 and 13, the processor 91 may accelerate the washing motor 93 to a preset maximum rotation speed dr (v) (a 2).

When the washing motor 93 is driven (a1), the processor 91 may generate a start signal SG 1. In response to the start signal SG1, the circulation pump motor 92 may start to operate.

When the circulation pump motor 92 is driven (B1), the processor 91 may accelerate the circulation pump motor 92 based on the motion information (B2).

The processor 91 may accelerate the circulation pump motor 92 to the maximum rotation speed Pr (V, H). When the circulation pump motor 92 reaches the target RPM (Pr (V, H)), the processor 91 may stop the acceleration of the circulation pump motor 92, thereby limiting the speed thereof (B3).

The processor 91 may rotate the washing motor 93 by a preset operation angle θ. The processor 91 may control the washing motor 93 such that a time when the washing motor 93 reaches the maximum rotation speed dr (v) and a time when the washing motor 93 rotates by the action angle θ correspond to each other.

When the washing motor 93 rotates to the action angle θ (a3), the processor 91 may generate an angle control completion signal SG 2. According to the angle control completion signal SG2, the circulation pump motor 92 may be decelerated (B4).

Referring to fig. 13, the processor 91 may control the washing motor 91 and the circulation pump motor 92 such that a time when the washing motor 93 reaches the maximum rotation speed dr (V) and a time when the circulation pump motor 92 reaches the maximum rotation speed Pr (V, H) correspond to each other.

However, a time delay such as a time required for the processor 91 to perform a process or a time required to transmit a signal may occur between a time t (SG2) at which the angle control completion signal SG2 is generated when the washing motor 93 is controlled to the movement angle θ (or the washing motor 93 reaches the maximum rotation speed dr (v) (a3)) and a time at which the circulation pump motor 92 starts to decelerate in response to the generated angle control completion signal SG 2. Therefore, as shown in fig. 13, in order to immediately decelerate the circulation pump motor 92 when the washing motor 93 reaches the maximum rotation speed dr (v), it is preferable that the processor 91 anticipates an angle control completion time (i.e., a time when the washing motor 93 reaches the maximum rotation speed dr (v)) and generates the angle control completion signal SG2 slightly earlier than the angle control completion time.

Fig. 14 illustrates a variation (a) in the number of rotations (a) of the drum and a variation (b) in the number of rotations of the pump according to an embodiment of the present invention. Fig. 15 shows the arrangement of the laundry in the drum in the middle of the filtering action. In fig. 15, (a) shows a case where a small amount of laundry is loaded in the drum, and (b) shows a case where a large amount of laundry is loaded in the drum.

The method for controlling a washing machine according to an embodiment of the present invention includes the step of rotating the drum 40 in one direction to prevent laundry from falling off the inner circumferential surface of the drum 40. This step corresponds to the filtering action described above.

Referring to fig. 14, 15 and 16, the processor 91 may perform control such that the rotation speed pr (f) of the circulation pump motor 92 is increased when the drum 40 is rotated in one direction (preferably, one or more times) during the filtering action. If the rotation speed of the drum 40 starts to increase during the filtering action, the centrifugal force applied to the laundry also increases, and the laundry closest to the inner circumferential surface of the drum 40 is sequentially adsorbed to the drum. That is, during the increase of the rotation speed of the drum 40 to the preset rotation speed dr (f) in the filtering action, the laundry located at the center of the drum 40 is not provided with a sufficient centrifugal force at an initial stage, thereby causing the laundry to move. Thereafter, if the rotation speed of the drum 40 is increased sufficiently, the position of most of the laundry (preferably, all of the laundry) in the drum 40 with respect to the drum 40 is fixed.

Specifically, if the amount of laundry in the drum 40 is equal to or less than a predetermined threshold, the laundry is generally gathered around the inlet of the drum 40 in the filtering action (see fig. 15 (a)). In this case, it is preferable to reduce the rotation speed of the circulation pump 36 so that the circulating water sprayed from at least one of the

nozzles

83a or 83b falls on the front of the drum 40.

In contrast, if the amount of laundry in the drum 40 is greater than the predetermined threshold value, when the rotation speed of the drum 40 is increased, the empty space in the drum 40 surrounded by the laundry extends rearward from the inlet of the drum 40, resulting in the form shown in (b) of fig. 15.

Controlling the rotational speed of the circulation pump 36 to increase the filtering action is contemplated from the extension of the empty space in the drum 40 that occurs during the filtering action described above. That is, when the empty space extends toward the rear of the drum 40, the injection pressure of at least one

nozzle

83a or 83b is controlled to be correspondingly increased, thereby allowing the water current to reach an area deep inside the drum 40.

In the filtering action, the processor 91 accelerates the washing motor 93 to the preset rotation speed dr (f), and when the washing motor 93 reaches the preset rotation speed dr (f), the processor 91 performs control to maintain the preset rotation speed dr (f) for a preset time period. The rotation speed dr (f) is determined in a speed range in which the laundry is rotated while being adsorbed to the inner circumferential surface of the drum 40, and the rotation speed dr (f) may be varied according to the load of the laundry, and may be set to approximately between 80rpm and 108 rpm.

The processor may accelerate the wash motor 93 to the rotational speed dr (f) with the set first acceleration slope Ag 1. Based on the time period tr1 until the highest rotational speed dr (f) is reached, the processor 91 may set a first acceleration slope Ag 1. The time period tr1 may be set differently according to the laundry load.

Alternatively, the processor 91 may perform control such that the rotation speed dr (f) is maintained until the washing motor 93 rotates by a set angle. In this case, the set angle may be different according to the laundry load.

In the filtering action, the maximum rotation speed pr (f) of the circulation pump motor 92 may be differently set according to the laundry load. That is, the processor 91 may set the maximum rotation speed pr (f) of the circulation pump motor 92 according to the sensed laundry load. The maximum rotation speed pr (f) of the circulation pump motor 92 may be set such that the maximum rotation speed pr (fs) in response to the sensed laundry load corresponding to the light load (or the first laundry load range I; see fig. 16) is higher than the maximum speed pr (fm) in response to the sensed laundry load corresponding to the heavy load (or the second laundry load range II; see fig. 16).

In this case, the rotation speed of the circulation pump 36 may be set to increase corresponding to the time t1 at which the rotation of the drum 40 accelerates. That is, the time for accelerating the rotation of the drum 40 is correlated with (or synchronized with) the time for increasing the rotation speed of the circulation pump 36.

In the filtering operation, the processor 91 may execute control so that the circulation pump motor 92 is accelerated to the set rotation speed pr (f), and when reaching the rotation speed pr (f), the rotation speed pr (f) is maintained.

The processor 91 may accelerate the circulation pump motor 92 to the rotation speed pr (f) with the set second acceleration slope Ag 2. The second acceleration slope Ag2 may be set equal to or less than the first acceleration slope Ag 1.

Alternatively, the processor 91 may set the second acceleration slope Ag2 based on the time period tr2 taken to reach the highest rotation speed pr (f). The time period Tr2 may be different according to the laundry load.

When the washing motor 93 is stopped, the processor 91 may generate a stop signal SG 4. In response to the stop signal SG4, the circulation pump motor 92 may be stopped (a 6).

The method for controlling a washing machine according to an embodiment of the present invention may further include the step of sensing the amount of laundry (hereinafter, referred to as "laundry load") in the drum 40. There are various known methods for calculating the laundry load. For example, the drum 40 may be accelerated with laundry loaded in the drum 40, and the laundry load may be determined based on a time period taken until the rotation speed of the drum 40 reaches a preset rotation speed. However, the aspect of the present invention is not limited thereto, and any other known method may be used to calculate the laundry load.

As described above, the control of the circulation pump 36 in performing the filtering action is applicable to the water supply/laundry soaking cycle or the rinsing cycle in the series of cycles shown in fig. 11.

Fig. 17 is a diagram illustrating a change (a) in the number of times of (rotation) of the drum and a change (b) in the number of times of (rotation) of the pump according to an embodiment of the present invention. Fig. 18 is a view for explaining a pressing action according to an embodiment of the present invention. Fig. 19 is a diagram for explaining a water supply/laundry soaking cycle according to an embodiment of the present invention. Hereinafter, description is provided with reference to fig. 17 to 19.

In the method for controlling a washing machine according to an embodiment of the present invention, in performing the squeezing action, the circulation pump 36 is accelerated in response to acceleration of the washing motor 93, and is decelerated in response to deceleration of the washing motor 93.

Specifically, in the method, the acceleration and deceleration of the washing motor 93 are alternately repeated, such that the washing motor 93 is accelerated to rotate together with the drum 40 while the laundry in the drum 40 is adsorbed to the drum 40 due to the centrifugal force, and then the washing motor 93 is decelerated to separate the laundry 40 from the drum 40. In this process, the circulation pump motor 92 is operated to spray water through at least one of the nozzles 83a or 93 b. At this time, the circulation pump motor 93 is accelerated in response to acceleration of the washing motor 93, and is decelerated in response to deceleration of the washing motor 93.

The processor 91 may accelerate the washing motor 93 to a first rotation speed (or a maximum rotation speed Dr (Q, H)) such that the laundry in the drum 40 rotates together with the drum 40, thereby forming an empty space surrounded by the laundry due to centrifugal force.

The maximum rotation speed DR (Q, H) of the washing motor 93 in the pressing action may be equal to or greater than 70rpm (preferably 80 rpm). The lowest rotation speed DR (Q, L) of the washing motor 93 may be defined as a lower limit of the set rotation speed range. The minimum rotation speed DR (Q, L) may be set to 35rpm or more and less than 55rpm (preferably 46 rpm).

Referring to fig. 18 (a), once the drum 40 starts to rotate, the laundry starts to rotate together with the drum 40 (see left drawing in fig. 18 (a)).

Referring to (b) of fig. 18, when the washing motor 93 is accelerated, the processor 91 may accelerate the circulation pump motor 92 within a preset rotation speed range such that water is sprayed through at least one

nozzle

83a or 83 b. At the time t (SG1) when the acceleration of the washing motor 93 starts, the processor 91 may start accelerating the circulation pump motor 92.

If the circulation pump motor 92 is accelerated to rotate at a predetermined speed or more, water may be sprayed from at least one of the

nozzles

83a or 83 b. In this case, the water sprayed from the at least one

nozzle

83a or 83b may be directed to an area near the front surface of the drum 40 on the inner circumferential surface of the drum 40 (see the leftmost drawing in (b) of fig. 18).

If the drum 40 rotates at a predetermined speed or more, the laundry in the drum 40 is adsorbed to the inner circumferential surface 42 of the drum 40 due to centrifugal force. In this case, a cylindrical space (or an empty space at the center of the drum 40) surrounded by the laundry is formed (see the second drawing from the left in (a) of fig. 18).

When the laundry is more closely adsorbed to the inner circumferential surface of the drum 40, a cylindrical space surrounded by the laundry may extend. That is, if the centrifugal force acting on the laundry increases as the rotation speed of the drum 40 increases, the cylindrical space surrounded by the laundry may extend.

The processor 91 may accelerate the circulation pump motor 92 in response to acceleration of the wash motor 93. The processor 91 may accelerate the circulation pump motor 92 to the maximum rotation speed Pr (Q, H). In the squeezing operation, the maximum rotation speed Pr (Q, H) of the circulation pump motor 92 may be a rotation speed (2200rpm to 3600rpm, preferably 3500rpm) at which the water jet ejected from the at least one

nozzle

83a or 83b reaches the rear surface of the drum 40.

When the circulation pump motor 92 is accelerated, the water sprayed from at least one

nozzle

83a or 83b may move to be further directed toward the rear surface of the drum 40. If the circulation pump motor 92 is accelerated to a predetermined speed or more, water sprayed from at least one

nozzle

83a or 83b may be directed toward the rear surface 41 of the drum 40 (see the second drawing from the left in (b) of fig. 18).

The processor 91 may decelerate the washing motor 93 if the rotation speed of the washing motor 93 reaches the maximum rotation speed Dr (Q, H). When the rotation speed of the drum 40 is reduced, an empty space formed in the drum 40, i.e., an empty space surrounded by laundry, is reduced (see the third diagram from the left in (a) of fig. 18). The washing motor 93 may be decelerated until reaching the second rotation speed (or the minimum rotation speed Dr (Q, L)).

In response to the deceleration of the washing motor 93, the processor 91 may decelerate the circulation pump motor 92 within a rotation speed range. While the wash motor 93 is decelerating, the processor 91 may decelerate the wash pump motor 92 up to the lowest rotation speed Pr (Q, L). At the beginning of the deceleration of the washing motor 93, the processor 91 may decelerate the circulation pump motor 92.

When the circulation pump motor 92 is rotated at the lowest rotation speed Pr (Q, L), the water stream sprayed from the at least one

nozzle

83a or 83b may reach a position closer to the front surface of the drum 40 than the rear surface 41 of the drum 40. The minimum rotation speed Pr (Q, L) may be from 1100rpm to 1600rpm, preferably 1300 rpm.

When the circulation pump motor 92 is decelerated, water sprayed from at least one

nozzle

83a or 83b may be gradually moved to be directed toward the front surface of the drum 40. If the circulation pump motor 92 is decelerated to a predetermined speed or less, the water sprayed from the nozzle 83a or the nozzle 83b may be directed to a position on the inner circumferential surface of the drum 40, which is closer to the front surface of the drum 40 than the rear surface 41 of the drum 40.

If the washing motor 93 decelerates to the minimum rotation speed Dr (Q, L), the processor 91 may accelerate the washing motor 93. When the rotation speed of the drum 40 increases, an empty space formed in the drum 40, i.e., an empty space surrounded by laundry, extends (see the fourth drawing from the left in (a) of fig. 18). The washing motor 93 may be accelerated until the maximum rotation speed Dr (Q, H) is reached.

In response to the acceleration of the washing motor 93, the processor 91 may accelerate the circulation pump motor 92 to the highest rotation speed Pr (Q, H) again.

In response to the deceleration of the washing motor 93, the processor 91 may decelerate the circulation pump motor 92 within a rotation speed range. When the washing motor 93 is decelerated, the processor 91 may decelerate the circulation pump motor 92 to the minimum rotation speed Pr (Q, L). At the beginning of the deceleration of the washing motor 93, the processor 91 may begin to decelerate the circulation pump motor 92.

The above-described acceleration and deceleration of the washing motor may be repeated a predetermined number of times, and the acceleration and deceleration of the circulation pump motor 92 may also be repeated in response to the acceleration and deceleration of the washing motor. The combination of the above-described squeezing action and the operation of the circulation pump 36 may be achieved during the water supply/laundry soaking cycle. Hereinafter, a more detailed description will be provided with reference to fig. 19. The water supply/laundry soaking cycle may include a detergent dissolving step and a laundry soaking step. The detergent dissolving step is performed with the detergent and water contained in the outer tub 31. In the laundry soaking step, the processor 91 may accelerate the washing motor 93 such that the laundry on the inner circumferential surface of the drum 40 is lifted without falling from the inner circumferential surface 42 of the drum 40 due to a centrifugal force, and then brake the washing motor 93 such that the laundry falls from the inner circumferential surface 42 of the drum 40. At this time, the drum driving motion may be a shaking motion, a rubbing motion, or a beating motion.

According to one embodiment, in the detergent dissolving step, the processor 91 may brake the washing motor 93 when the laundry is lifted from the lowest position in the drum to a height corresponding to a set angle set to a rotation angle less than 220 degrees of the drum 40.

According to an embodiment, the processor 91 may accelerate the washing motor 93 to the maximum rotation speed dr (v) and then brake the washing motor 93. The processor 91 may repeat the operation of accelerating the washing motor 93 to the maximum rotation speed dr (v) and then braking the washing motor 93. The processor 91 may repeat the operation of accelerating the washing motor 93 to the maximum rotation speed dr (v) and then braking the washing motor 93 by alternately changing the rotation direction of the drum 40.

In the detergent dissolving step, the processor 91 may control the circulation pump motor 92 such that water is sprayed through at least one

nozzle

83a or 83 b. In this case, the processor 91 may accelerate the circulation pump motor 92 in response to acceleration of the washing motor 93, and decelerate the circulation pump motor 92 in response to braking (or deceleration) of the washing motor 93.

The detergent dissolving step may be performed by filling water in which detergent is dissolved to a first water level in the outer tub 31. Before the detergent dissolving step, the water supply valve 94 may be opened by the processor 91 so that the water supplied through the water supply hose is supplied to the outer tub 31 together with the detergent contained in the dispenser 35, and then the detergent dissolving step may be performed. Meanwhile, the first water level may be a water level approximately allowing the washing water to reach the inside of the drum 40.

The laundry soaking step may be performed when the water level in the outer tub 31 reaches a second water level higher than the first water level. After the detergent dissolving step, the processor 91 may open the water supply valve 94 again, thereby supplying water to the inside of the outer tub 31. The detergent in the dispenser has been entirely used in the water supply of the first water level, and thus, in the water supply to the second water level, although the water guided through the water supply hose passes through the dispenser, the water may be supplied only to the inside of the outer tub 31 without adding the detergent. However, the aspect of the present invention is not limited thereto, and an additional flow path for guiding the water supplied through the water supply valve 94 without passing through the dispenser 35 may be further provided, and in this case, the water supply to the second water level may be performed through the additional flow path.

The detergent can be effectively dissolved in the detergent dissolving step, and the laundry can be effectively soaked in the washing water in which the detergent is dissolved in a short time in the laundry soaking step.

In the laundry soaking step, the pressing action described above with reference to fig. 17 and 18 and the operation of the circulation pump 36 may be controlled accordingly.

Meanwhile, in the laundry soaking step, the processor 91 may set the maximum rotation speed and/or the minimum rotation speed of the washing motor 93 according to the load of the laundry in the drum 40. For example, if the maximum rotation speed of the washing motor 93 in response to a small laundry load in the drum 40 is Dr (Q, H1), and the maximum rotation speed of the washing motor 93 in response to a large laundry load in the drum 40 is Dr (Q, H2), the processor 91 may set Dr (Q, H2) higher than Dr (Q, H1). In this way, when the laundry load is large, even the central portion of the drum 40 is filled with the laundry, and in order to rotate the drum 40 with all the laundry adsorbed to the inner circumferential surface of the drum 40, a greater centrifugal force is required as compared to the case where the laundry load is small. Therefore, when the laundry load is large, the maximum rotation speed is set to be higher than when the laundry load is small, so that the laundry is adsorbed to the inner circumferential surface 42 of the drum 40.

The processor 91 may set the rotation speed range of the circulation pump motor 92 according to the sensed laundry load. For example, in case that the maximum rotation speed of the circulation pump motor 92 in response to a small laundry load in the drum 40 is Pr (Q, H1), and the maximum rotation speed of the circulation pump motor 92 in response to a large laundry load in the drum 40 is Pr (Q, H2), then the processor 91 may set Pr (Q, H2) higher than Pr (Q, H1).

As described above with reference to fig. 15, the laundry is gathered from the front end to the rear end of the drum 40. If the maximum rotation speed of the circulation pump motor 92 is increased according to the load of the laundry, the water flow may be allowed to reach the laundry near the rear surface of the drum 40, thereby enhancing the laundry soaking performance. In doing so, the laundry may be further adsorbed to the inner circumferential surface 42 of the drum 40.

The method of controlling a washing machine using the above-described squeezing action can effectively soak laundry in detergent-dissolved water in an initial washing stage, thereby reducing the time for soaking the laundry and accordingly reducing the overall washing time.

Further, by changing the rotation speed of the circulation pump motor 92, circulating water is effectively sprayed in response to the movement of the laundry in the squeezing motion, thereby effectively soaking the laundry.

Fig. 20 is a diagram for explaining a method for controlling a washing machine according to another embodiment of the present invention. Hereinafter, description will be made with reference to fig. 20. A method for controlling a washing machine according to another embodiment of the present invention may include a water supply step of supplying water with detergent to an inside of the outer tub 31 to a first water level. The processor 91 may control the water supply valve 94 to supply water to the dispenser 35.

After the water supply step, a detergent dissolving step (a "dissolve detergent" step in fig. 20) of operating the circulation pump 36 at the first speed and repeating acceleration and deceleration of the washing motor 93 is performed. The first speed may be set in a range that does not allow the water discharged from the circulation pump 36 to reach the at least one

nozzle

83a or 83b, or does not allow the sprayed water to reach the inside of the drum 40 even if the water is sprayed through the at least one

nozzle

83a or 83 b. The first speed may be set to be equal to or lower than 1500 rpm.

In the above, "at least one nozzle" is exemplified by the two

nozzles

83a and 83b, but is merely an example, and at least one nozzle may be variously implemented. For example, the at least one nozzle may include two or more lower nozzles that spray water to a first region on the inner circumferential surface of the drum 40, and two or more intermediate nozzles that are supplied with water through a flow path shared with the two or more lower nozzles and are disposed higher than the two or more lower nozzles to spray water in a second region on the inner circumferential surface of the drum 40.

If the first and second regions are defined with reference to a vertical line passing through the center of the ring-shaped gasket 60 installed at the inlet of the tub 31 when viewed from the front side of the drum, it may be provided that: a first intermediate nozzle disposed in the first region higher than the center of the pad 60 to spray water downward toward the second region; a first lower nozzle disposed in the first region below the center of the pad 60 to spray water upward toward the second region; a second intermediate nozzle disposed in the second region higher than the center of the pad 60 to spray water downward toward the first region; and a second lower nozzle disposed in the second region below the center of the pad 60 to spray water upward toward the first region. In this case, the water pumped by the circulation pump 36 may be directed to the first lower nozzle, the first middle nozzle, the second lower nozzle, and the second middle nozzle.

Further, the upper nozzle may be disposed higher than the first and second intermediate nozzles. The upper nozzle may be a nozzle for spraying circulating water or a direct water nozzle for supplying water that passes through the water supply valve without being mixed with the detergent. Alternatively, the upper nozzle may be a nozzle for supplying water, which is mixed with the fabric softener after passing through a detergent box filled with the fabric softener.

The first and second lower nozzles and the first and second intermediate nozzles may be supplied with circulating water through the circulating water guide flow path. For example, directing the flow path may include: an inlet connected to a circulating water conduit 18; and a first guide flow path and a second guide flow path branched from the inlet. The first lower nozzle and the first intermediate nozzle may be disposed in the first guide flow path, and the second lower nozzle and the second intermediate nozzle may be disposed in the second guide flow path.

In the detergent dissolving step, the rotation speed of the circulation pump 36 may be set such that water is sprayed only through the first and second lower nozzles, and water is not sprayed through the first and second intermediate nozzles.

In the detergent dissolving step, the circulation pump 36 serves as an agitator that agitates the washing water to uniformly dissolve the detergent. In the detergent dissolving step, the circulation pump 36 is rotated at such a low speed that the water sprayed from the nozzle 83a or the nozzle 83b cannot reach the laundry in the drum 40, thereby preventing the water having the detergent incompletely dissolved therein from acting on the laundry.

Since the above detergent dissolution step is performed, it is possible to effectively dissolve the detergent in water in the initial washing stage, thereby improving the washing effect in the washing step.

In addition, the circulation pump motor may be rotated even when there is insufficient water in the drum at the initial washing stage, thereby effectively dissolving the detergent.

The processor 91 may perform control such that the washing motor is repeatedly accelerated and braked while the circulation pump 36 is rotated at the first rotation speed. In this case, the laundry in the drum 40 is adsorbed to the inner circumferential surface of the drum 40 in response to acceleration of the washing motor 93, and falls from the inner circumferential surface in response to braking of the washing motor 93.

In the detergent dissolving step, the washing motor 91 may be braked when the laundry is lifted from the lowermost position of the drum 40 to a height corresponding to a set angle set to be less than a rotation angle of the drum 40 of less than 180 degrees. That is, in the detergent dissolving step, a drop trigger action by braking (effecting) may be performed.

Although not shown, after the detergent dissolving step, an additional water supply step of supplying water into the outer tub 31 to increase the water level in the outer tub 31 from the first water level to the second water level is performed.

When the water level in the outer tub 31 is increased to the second water level through the additional water supply step, the laundry soaking step of repeating the acceleration and deceleration of the washing motor 93 is (performed), so that the circulation pump 36 is accelerated in response to the acceleration of the washing motor 93 and is decelerated in response to the deceleration of the washing motor 93. In the laundry soaking step, the circulating water may be sprayed through at least one

nozzle

83a or 83b at a higher water pressure than in the detergent dissolving step.

According to one embodiment, in the laundry soaking step, the circulating water may be sprayed through the first and second lower nozzles and the first and second intermediate nozzles.

After the laundry soaking step, a washing step (see "washing" step in fig. 20) may be performed. In the washing step, the washing motor 93 may be continuously rotated a plurality of times. Hereinafter, a process of accelerating the washing motor 93 to a predetermined speed, rotating the washing motor 93 while maintaining the predetermined speed, and braking the washing motor 93 to stop is defined as one rotation cycle. The rotation cycle may correspond to a kneading action or a tumbling action.

The rotation cycle may be repeated a plurality of times. Further, the operation and stop of the circulation pump 36 may be repeated while repeating the rotation cycle. The circulation pump 36 may begin to operate whenever a spin cycle begins. When the rotation cycles stop (i.e., the intervals between the rotation cycles), the circulation pump 36 may stop operating (see (a) and (b) of fig. 20).

During multiple iterations of the circulation pump 36, the rotational speed of the circulation pump 36 may be increased. Specifically, the multiple operations of the circulation pump 36 may include: a first operation in which the circulation pump 36 is rotated at a first rotation speed; and a second operation in which the circulation pump 36 is rotated at a second rotation speed higher than the first rotation speed after the first operation. Here, the second operation represents a case where the circulation pump 36 is rotated at a higher speed than before, and the first operation is an operation performed just before the second operation, in which the circulation pump 36 is rotated at a speed that has not been accelerated yet.

Meanwhile, a step of additionally supplying water into the outer tub 32 during the washing step may be further performed. The "additional water supply" in (a) of fig. 20 is to indicate a time for additionally supplying water into the outer tub 31.

When the circulation pump 36 is operated after the water is additionally supplied into the outer tub 31, the rotation speed of the circulation pump 36 may be set to be higher than that in the previous operation. Since the amount of water contained in the outer tub 31 is increased due to the additional water supply, the circulation pump 36 is controlled to rotate at a higher speed, thereby increasing the pressure and flow rate of the water sprayed through the at least one

nozzle

83a or 83 b.

According to one embodiment, in the washing step, water may be sprayed through a pair of lower nozzles and a pair of middle nozzles by the rotation of the circulation pump 36.

Meanwhile, in the washing step, the washing pump 36 may be controlled such that the water pumped by the circulation pump 36 is sprayed through the pair of lower nozzles, but is now allowed to reach the pair of middle nozzles.

Further, in the washing step, when water is sprayed through the pair of middle nozzles and the pair of lower nozzles, water may be sprayed through the direct water spray nozzle 57.

After the washing step, a rinsing step ("rinsing" in fig. 20) may be performed. That is, the steps of accelerating the washing motor 93 to a preset contact maintaining speed such that the laundry in the drum 40 rotates while being adsorbed to the inner circumferential surface of the drum 40, and controlling the washing motor 93 to rotate while maintaining the contact maintaining speed may be performed. Speed may be performed. In this step, the driving action of the drum 40 may correspond to the filtering action described above.

In order to spray water through the at least one nozzle during the filtering action, the step of accelerating the circulation pump 36 in response to the acceleration of the washing motor 93 may be performed.

By adopting the method for controlling a washing machine according to the present embodiment, it is possible to adjust the intensity of water sprayed through the

nozzle

83a or 83b in response to a change in the water level of the drum 40, thereby improving washing performance.

Further, it is possible to perform washing with washing water in which detergent is highly concentrated at a low retention water level of the drum 40 and then perform washing at an elevated water level, thereby improving washing performance.

If the rotation speed of the circulation pump motor 92 is maintained at a high speed, the water level in the drum 40 is lowered and additional water supply is required. In this case, more water may be used to wash the laundry, or it may be difficult to wash the laundry with washing water in which the detergent is highly concentrated. According to the embodiment, since the rotation speed of the circulation pump motor 92 is changed according to the water level in the drum 40, a smaller amount of water may be used when washing laundry and a highly concentrated washing operation may be performed.

Further, if the water level in the drum 40 is raised due to the additional water supply, the pressure of the water to be sprayed through the nozzles is increased, thereby improving the washing performance under the physical influence of the water pressure.

In addition, the additional water supply amount, the rotation speed of the circulation pump motor and the interval between water supplies are changed according to the water level of the washing water, thereby enabling effective washing and shortening the entire washing cycle.

Fig. 21 is a diagram for explaining a method for controlling a washing machine according to another embodiment of the present invention. The embodiment described with reference to fig. 21 includes another embodiment that may be the washing step described above.

The following steps may be performed: the acceleration and deceleration of the circulation pump 36 is repeated one or more times while the washing motor is continuously rotated in one direction. When the washing motor 93 continuously rotates in one direction, the laundry in the drum 32 may be repeatedly lifted to a predetermined height and dropped therefrom. In this case, the circulation pump 36 may operate one cycle, and the washing motor 93 operates two or more cycles. In one embodiment, the circulation pump 36 is shown operating for one cycle and the washing motor 93 for three cycles, but this is merely an example.

The water supply to the outer tub 31 may be performed in stages. The processor 91 may control the water supply valve 94 such that the water level in the outer tub 31 rises to a first water level H1 (first water supply). When the water level in the outer tub 31 reaches the first water level H1, a first cycle in which the circulation pump 36 rotates at the first speed Pr (R, H1) may be performed. The speed of rotation Pr (R, H1) may be from 1800rpm to 2200rpm (preferably 2000 rpm).

In the structure provided with the pair of lower nozzles and the pair of intermediate nozzles, if the rotary pump motor 92 is rotated at the rotation speed Pr (R, H1), water may be similarly sprayed only through the pair of lower nozzles, not through the pair of intermediate nozzles. That is, if the circulation pump motor 92 is rotated at the rotation speed Pr (R, H1), the discharge pressure of the circulation pump 36 is insufficient to increase the water to reach the pair of intermediate nozzles and to be sprayed therefrom. However, even in this case, since water can be injected through the pair of lower nozzles, the circulation pump motor 92 does not run idle.

After the first cycle of the circulation pump 36, the processor 91 may control the water supply valve 94 such that the water level in the outer tub 31 rises to the second water level H2 (second water supply). When the water level in the outer tub 31 reaches the second water level H2, a second cycle in which the circulation pump 36 rotates at the second speed PR (R, H2) may be performed. The speed of rotation Pr (R, H2) may be from 2250rpm to 2750rpm, preferably 2500 rpm.

After the second cycle of the circulation pump 36, the processor 91 may control the water supply valve 94 such that the water level in the outer tub 31 reaches the third water level H3 (third water supply). When the water level in the outer tub 31 reaches the third water level H3, a third cycle in which the circulation pump 36 rotates at the third rotation speed Pr (R, H3) may be performed.

After the third cycle of the circulation pump 36, the processor 91 may control the water supply valve 94 such that the water level in the outer tub 31 reaches the fourth water level H4 (fourth water supply). When the fourth water supply has been provided, the fourth cycle of the circulation pump 36 may be performed, and in this case, the circulation pump 36 may be rotated at the third speed PR (R, H3) as in the third cycle. The rotation speed Pr (R, H3) may be 2520 to 3080rpm (preferably 2800 rpm).

Meanwhile, the processor 91 may control the water supply valve 94 such that water is sprayed through the direct water spray nozzle 57 at the last water supply (fourth water supply in this embodiment) in the washing step. In this case, water may be supplied to the softener container of the dispenser 35 in which the fabric softener is contained, and thus, water may be supplied to the water injection nozzle 57 together with the fabric softener.

The water introduced through the water supply valve 94 may pass through the softener container along a predetermined flow path and then be supplied to the direct water nozzle 57 together with the fabric softener.

However, the aspect of the present invention is not limited thereto, and the raw water (water supplied from the external water source) may be sprayed through the direct water nozzle 58, and the water having passed through the softener container of the dispenser 35 may be directly supplied to the outer tub 31 during the spraying operation.

Meanwhile, the direct water nozzle 57 may be disposed higher than the pair of intermediate nozzles. Preferably, intermediate nozzles are provided on the left and right sides of the liner 60, respectively, and the direct water nozzles 57 may be interposed therebetween.

Further, a pair of lower nozzles may be provided at the left and right sides of the gasket 60, respectively. In this case, when water is simultaneously sprayed from the direct water nozzles 57, the pair of middle nozzles, and the pair of lower nozzles, the water flow may form a star shape when viewed from the front.

Meanwhile, referring to fig. 21, the processor 91 may control additional water supply on a time basis. That is, the processor 91 may start the first water supply at time t-t (w1), start the second water supply at time t-t (w2), start the third water supply at time t-t (w3), and start the fourth water supply at time t-t (w 4).

In this case, the time interval t (w2) -t (w1) between the first and second water supplies, the time interval t (w3) -t (w2) between the second and third water supplies, and the time interval t (w4) -t (w3) between the third and fourth water supplies may be preset values.

The processor 91 may set a time interval t (w3) -t (w2) between the second water supply and the third water supply to be greater than a time interval t (w2) -t (w1) between the first water supply and the second water supply. This is because, if the water level of the washing water in the drum 40 is raised, a longer washing time may be required.

Also, the processor 91 may set the time interval t (w4) -t (w3) between the third and fourth water supplies to be different from the time interval t (w2) -t (w1) between the first and second water supplies or the time interval t (w3) -t (w2) between the second and third water supplies.

The processor 91 may set the amount of increase in the rotation speed of the circulation pump motor 92 based on the amount of water supplied in each of the first to third water supplies. The processor 91 may accelerate the circulation pump motor 92 at every time of performing the first water supply to the third water supply according to the amount of increase in the rotation speed of the circulation pump motor 92.

However, the rotation speed of the circulation pump motor 92 may be set not to exceed the maximum rotation speed set according to the sensed laundry load. The processor 91 may set the maximum rotation speed of the circulation pump motor 92 according to the laundry load sensed in the laundry load sensing step.

The processor 91 may gradually accelerate the circulation pump motor 92 until the set maximum rotational speed is reached. After the rotary pump motor 92 reaches the maximum rotation speed, the processor 91 may control the circulation pump motor 92 to maintain the maximum rotation speed despite the water level in the drum 40 being changed.

Even when the water level in the drum 40 is gradually increased by the additional water supply, the processor 91 may maintain the maximum rotation speed of the circulation pump motor 92 without accelerating the circulation pump motor 92 beyond the maximum rotation speed. According to an embodiment, at the last water supply (fourth water supply in this embodiment) in the washing step, the water in which the detergent is dissolved may be supplied to the outer tub 31. The dispenser 35 may further include a detergent container in which detergent is contained. The water introduced through the water supply valve 94 may pass through the detergent container along a predetermined flow path and then be supplied to the outer tub 31 together with the detergent.

The present invention as described above can be implemented as codes that can be written on a computer-readable medium in which a program is recorded and thus read by a computer. The computer-readable medium includes all types of recording apparatuses in which data is stored in a computer-readable manner. Examples of the computer readable recording medium may include a Hard Disk Drive (HDD), a Solid State Disk (SSD), a Silicon Disk Drive (SDD), a Read Only Memory (ROM), a Random Access Memory (RAM), a compact disc read only memory (CD-ROM), a magnetic tape, a floppy disk, and an optical data storage device. Further, the computer readable medium may be implemented as a carrier wave (e.g., data transmission through the internet). Further, the computer may include a processor or controller.

Claims

1. A method for controlling a washing machine having an outer tub (31) for containing water, a drum (40) rotatably disposed in the outer tub (31), at least one spray nozzle (57) disposed in front of the drum (40) to spray water to the drum (40), a washing motor (93) configured to rotate the drum (40), and a circulation pump (36) configured to circulate water discharged from the outer tub (31) to the at least one spray nozzle (57), the method comprising:

a step (a) of supplying water having detergent into the outer tub (31) to reach a first water level;

a step (b) of operating the circulation pump (36) at a first speed such that the washing motor (93) is repeatedly accelerated and braked when the circulation pump (36) is operated at the first speed, causing laundry in the drum (40) to be adsorbed to the inner circumferential surface of the drum (40) in response to acceleration of the washing motor (93), and causing the laundry to fall from the inner circumferential surface of the drum (40) in response to deceleration of the washing motor (93);

a step (c) of supplying water into the outer tub (31) such that a water level in the outer tub (31) rises from the first water level to a second water level; and

a step (d) of repeating acceleration and deceleration of the washing motor (93) such that the circulation pump (36) is accelerated in response to the acceleration of the washing motor (93) and the circulation pump (36) is decelerated in response to the deceleration of the washing motor (93), wherein the pressure of the water from the circulation pump (36) in the step (b) is lower than the maximum pressure of the water from the circulation pump (36) in the step (d).

2. The method according to claim 1, wherein the braking of the washing motor (93) in the step (b) is performed when laundry is lifted from a lowest position in the drum (40) to a height corresponding to a set angle set to be less than a rotation angle of 180 degrees of the drum (40).

3. The method according to claim 1 or 2, wherein the first speed is set in a range in which water discharged from the circulation pump (36) cannot reach any one of the at least one nozzle (57), or even if the water reaches the at least one nozzle (57), the sprayed water cannot reach the inside of the drum (40), or in a case where the at least one nozzle (57) includes a lower nozzle and an intermediate nozzle installed higher than the lower nozzle, the water from the circulation pump (36) is supplied only to the lower nozzle and not to the intermediate nozzle.

4. The method of any of claims 1-3, wherein the first speed is equal to or below 1500 rpm.

5. The method of any one of claims 1-4, further comprising, after step (d): a step (e) of repeating the operation and stop of the circulation pump (36) a plurality of times while continuously rotating the washing motor (93) in one direction.

6. The method according to claim 5, wherein, in the step (e), the washing motor (93) is continuously rotated in one direction so that the laundry in the drum (40) is repeatedly lifted to a predetermined height and dropped therefrom.

7. A method according to claim 5 or 6, wherein in step (e) the washing motor (93) is decelerated after the drum (40) has rotated 360 degrees or more.

8. The method of claim 5, 6 or 7,

wherein, in the step (e), the operation of the circulation pump (36) is repeated a plurality of times in response to the washing motor (93) continuously rotating a plurality of times in one direction; and

wherein the multiple operation of the circulation pump (36) comprises:

a first operation in which the circulation pump (36) rotates at a first rotational speed; and

a second operation, wherein the circulation pump (36) rotates at a second rotational speed higher than the first rotational speed after the first operation.

9. Method according to any of claims 5-8, further comprising the step of additionally supplying water into the outer tub (40) during step (e), wherein the method comprises the steps of: setting a rotation speed of the circulation pump (36) to be higher than that in a previous operation when the operation of the circulation pump (36) is performed a plurality of times and the operation of the circulation pump (36) is performed after additional water supply into the outer tub (40).

10. The method according to any one of claims 5 to 9, wherein the at least one nozzle (57) comprises:

two or more lower nozzles spraying water to a first region on an inner circumferential surface of the drum (40);

two or more intermediate nozzles supplied with water along a flow path shared with the two or more lower nozzles and disposed higher than the two or more lower nozzles in the flow path, thereby spraying water to a second region on the inner circumferential surface of the drum (40); and

wherein the rotation of the circulation pump (36) is controlled in the step (e) such that water is sprayed from the two or more lower nozzles and the two or more intermediate nozzles.

11. The method of claim 10, wherein step (e) comprises the step of controlling the circulation pump (36) such that water pumped by the circulation pump (36) is sprayed through the two or more lower nozzles but does not reach the two or more intermediate nozzles.

12. The method according to claim 11, wherein the washing machine further comprises a direct water nozzle (57) for spraying water supplied through a water supply valve (94) into the drum (40),

wherein the step (e) includes the step of opening the water supply valve (94) to spray water through the direct water nozzle (57) while spraying water through the two or more intermediate nozzles and the two or more lower nozzles.

13. The method of claim 5, further comprising, after said step (e):

a step (f) of accelerating the washing motor (93) to a contact maintaining speed such that the laundry in the drum (40) rotates while being adsorbed to the inner circumferential surface of the drum (40), and rotating the washing motor (93) while maintaining the contact maintaining speed; and

a step (g) of accelerating the circulation pump (36) in response to acceleration of the washing motor (93) so that water is sprayed through the at least one nozzle (57).

14. A washing machine comprising:

an outer tub (31) for holding water;

a drum (40) rotatably disposed in the tub (31);

at least one nozzle (57) provided in front of the drum (40) to spray water toward the drum (40);

a washing motor (93) configured to rotate the drum (40);

a circulation pump (36) configured to circulate water drained from the outer tub (31) to the at least one nozzle (57); and

a processor (91) configured to perform the method according to any one of claims 1 to 13.