Washing machine capable of compensating for state of imbalance

Abstract

A washing machine which can spin-dry is disclosed. The washing machine includes an imbalance compensation means for compensating for an unbalanced drum resulting from laundry loading conditions. The imbalance correction means comprises: an annular trough unit provided on the outer circumferential edge portion of the drum; and a water supply unit for supplying water into the annular trough unit. A control unit operates the water supply unit when spin-drying. The control unit compensates for the unbalanced drum by adjusting the water supply to the annular trough unit according to the rotational speed of the rotating drum.

Description

Washing machine capable of correcting imbalance

[0001] The present disclosure relates to a washing machine capable of correcting imbalance.

[0002] The weight and absorption capacity of laundry during washing vary depending on the type and material of the items. Additionally, the position of the laundry changes within the rotating drum during the wash cycle. Consequently, a center deviation of the rotating drum—so-called imbalance—occurs with every wash cycle. In the spin-drying process, where the drum rotates at high speeds, this imbalance causes abnormal vibrations in the washing machine. Therefore, various countermeasures have been devised to address this imbalance, aiming to prevent contact damage caused by abnormal vibrations, reduce vibration noise, and shorten spin-drying times through stable high-speed rotation.

[0003] For example, to provide vibration damping, the tub of the washing machine is installed inside the housing via a structure suspended by support springs and a structure elastically supported by dampers. In addition, heavy weights are attached to the tub. Furthermore, balancers such as ball balancers and liquid balancers may be applied to the drum. The imbalance can be corrected by using the balancers to offset the center of gravity of the drum deflected by the laundry.

[0004] A washing machine according to one aspect of the present disclosure is a washing machine capable of performing a spin-drying process. The disclosed washing machine comprises a housing, a tub, a drum, and a drive unit. The tub is capable of holding water and is elastically supported inside the housing. The drum is capable of receiving laundry and is rotatably installed inside the tub. The drive unit rotates the drum. The washing machine includes an imbalance correction means for correcting an imbalance of the drum caused by the condition of receiving laundry. The imbalance correction means includes an annular trough portion disposed at the outer edge portion of the drum and a water supply portion for injecting water into the annular trough portion. A control unit controls the drive unit and the imbalance correction means to correct the imbalance of the drum by adjusting the water supply condition to the annular trough portion according to the rotational speed of the rotating drum when performing a spin-drying process.

[0005] FIG. 1 is a schematic diagram of a washing machine according to one embodiment of the present disclosure.

[0006] FIG. 2 is a schematic cross-sectional perspective view illustrating the tub and the area around the water injection nozzle.

[0007] Figure 3 is a schematic perspective view illustrating the annular trough and the area around the water supply nozzle.

[0008] FIG. 4 is a detailed view of one embodiment of an annular trough.

[0009] Figure 5 is a cross-sectional view Y1-Y1 of the annular trough portion shown in Figure 4.

[0010] Figure 6 shows an example of dividing a reservoir into multiple reservoir cells.

[0011] Figure 7 illustrates an example of the arrangement relationship between a water supply nozzle and an annular trough.

[0012] Figure 8 shows a simplified view of the results of investigating the effect of the injection angle of the injected water relative to the water surface on the water flow through a simulation of a fluid dynamics-based division.

[0013] FIG. 9 illustrates a block diagram of a control unit and its related components related to unbalance correction control.

[0014] FIG. 10 is a schematic diagram of a drum of a dehydration process viewed from the front, illustrating an example of unbalance correction control.

[0015] Figure 11 is a diagram illustrating an example of unbalance correction control, showing the rotational speed profile of the drum in the dewatering process, the control profile of the water supply valve, and the water supply amount profile.

[0016] Figure 12a shows the water supply condition.

[0017] Figure 12b shows the drainage state.

[0018] FIG. 13 is a schematic diagram of a washing machine according to one embodiment of the present disclosure.

[0019] Fig. 14 is an enlarged view of the annular trough portion shown in Fig. 13.

[0020] FIG. 15 is a schematic diagram of a washing machine according to one embodiment of the present disclosure.

[0021] Figure 16 illustrates an example of unbalance correction control before improvement.

[0022] FIG. 17a is a diagram showing the first search step in an example of an improved unbalanced correction control.

[0023] FIG. 17b is a diagram showing the second search step in an example of an improved unbalanced correction control.

[0024] FIG. 17c is a diagram showing the third search step in an example of an improved unbalanced correction control.

[0025] Figure 18 illustrates an example of an unbalance amount adjustment step.

[0026] FIG. 19 illustrates an example of a change in the amount of unbalance in an unbalance correction process by an improved unbalance correction control that was measured.

[0027] Figure 20 illustrates the relationship between the angle error between the estimated unbalanced position and the actual unbalanced position obtained by testing, and the angle error between the actual water supply position and the optimal water supply position.

[0028] Figure 21 illustrates the relationship between the angle error between the estimated unbalanced position and the actual unbalanced position obtained by testing, and the amount of residual unbalance after unbalance correction control.

[0029] FIGS. 22a and FIGS. 22b are flowcharts showing an example of improved unbalance correction control performed by a control unit.

[0030] The various embodiments of this document and the terms used therein are not intended to limit the technical features described in this document to specific embodiments, and should be understood to include various modifications, equivalents, or substitutions of said embodiments.

[0031] In relation to the description of the drawings, similar reference numerals may be used for similar or related components.

[0032] The singular form of the noun corresponding to the item may include one or multiple items, unless the relevant context clearly indicates otherwise.

[0033] In this document, each of the phrases such as "A or B", "at least one of A and B", "at least one of A or B", "A, B or C", "at least one of A, B and C", and "at least one of A, B, or C" may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof.

[0034] For example, the phrase “at least one of A, B, and C” may include one of A, B, C, A and B, A and C, B and C, and A and B and C.

[0035] The term "and / or" includes a combination of multiple related described components or any of the multiple related described components.

[0036] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish a component from another corresponding component and do not limit the components in other aspects (e.g., importance or order).

[0037] Where any (e.g., 1st) component is referred to as "coupled" or "connected" to another (e.g., 2nd) component, with or without the terms "functionally" or "communicationly," it means that said any component may be connected to said other component directly (e.g., via a wire), wirelessly, or through a third component.

[0038] Terms such as "include" or "have" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in this document, and do not preclude the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0039] When it is said that a component is "connected," "combined," "supported," or "in contact" with another component, this includes not only cases where the components are directly connected, combined, supported, or in contact, but also cases where they are indirectly connected, combined, supported, or in contact through a third component.

[0040] When it is said that a component is located "on" another component, this includes not only cases where one component is in contact with the other, but also cases where another component exists between the two components.

[0041] A clothing processing device is a concept that encompasses a device for washing clothing (objects to be washed), a device for drying clothing (objects to be dried), and a device capable of performing both washing and drying of clothing. In the term 'clothing processing device,' 'clothing' refers to objects to be processed (objects to be washed or objects to be dried) and does not refer only to literal clothing. A washing machine is an example of a clothing processing device, and washing machines according to various embodiments can perform washing, rinsing, spin-drying, and drying processes.

[0042] Washing machines according to various embodiments may include a top-loading washing machine in which a laundry inlet for loading or unloading laundry is provided to face upward, or a front-loading washing machine in which a laundry inlet is provided to face forward. Washing machines according to various embodiments may include washing machines with loading methods other than top-loading washing machines and front-loading washing machines.

[0043] In the case of a top-loading washing machine, laundry can be washed using a water flow generated by a rotating body such as a pulsator. In the case of a front-loading washing machine, laundry can be washed by rotating the drum to repeatedly raise and lower the laundry. A front-loading washing machine may include a washing machine capable of drying laundry contained inside the drum. The washing machine capable of drying may include a hot air supply device for supplying high-temperature air into the drum and a condensation device for removing moisture from the air discharged from the drum. As an example, the washing machine capable of drying may include a heat pump device. Washing machines according to various embodiments may include washing machines with washing methods other than those described above.

[0044] A washing machine according to various embodiments may include a housing that accommodates various components inside. The housing may be provided in the form of a box with a laundry input opening formed on one side.

[0045] The washing machine may include a door for opening and closing a laundry input. The door may be rotatably mounted to the housing by means of a hinge. At least one part of the door may be made transparent or translucent so that the interior of the housing is visible.

[0046] The washing machine may include a tub provided inside the housing to store water. The tub is provided in a roughly cylindrical shape with a tub opening formed on one side, and may be positioned inside the housing such that the tub opening corresponds to the laundry inlet.

[0047] The tub can be connected to the housing by a damper. The damper can absorb vibrations generated during the rotation of the drum and attenuate vibrations transmitted to the housing.

[0048] The washing machine may include a drum designed to accommodate laundry.

[0049] The drum may be positioned inside the tub such that a drum opening provided on one side corresponds to a laundry inlet and a tub opening. Laundry may pass through the laundry inlet, the tub opening, and the drum opening in sequence to be received inside the drum or withdrawn from the drum.

[0050] The drum can rotate inside the tub and perform respective actions according to the washing, rinsing, and / or spin-drying cycles. A number of holes are formed in the cylindrical wall of the drum so that water stored in the tub can flow into the interior of the drum or out of the exterior of the drum.

[0051] The washing machine may include a drive unit configured to rotate the drum. The drive unit may include a drive motor and a rotating shaft for transmitting the driving force generated by the drive motor to the drum. The rotating shaft may pass through the tub and be connected to the drum.

[0052] The drive unit can rotate the drum in the forward or reverse direction to perform each operation according to the washing, rinsing, and / or spin-drying, or drying cycles.

[0053] The washing machine may include a water supply device configured to supply water to the tub. The water supply device may include a water supply pipe and a water supply valve provided in the water supply pipe. The water supply pipe may be connected to an external water source. The water supply pipe may extend from the external water source to a detergent dispenser and / or the tub. Water may be supplied to the tub via the detergent dispenser. Water may be supplied to the tub without passing through the detergent dispenser.

[0054] The water supply valve can open or close the water supply pipe in response to an electrical signal from the control unit. The water supply valve can allow or block the supply of water from an external water source to the tub. The water supply valve may include, for example, a solenoid valve that opens and closes in response to an electrical signal.

[0055] The washing machine may include a detergent dispenser configured to supply detergent to the tub. The detergent dispenser may include a manual detergent dispenser in which the user must add the detergent to be used for each wash cycle, and an automatic detergent dispenser that stores a large amount of detergent and automatically dispenses a predetermined amount during a wash cycle. The detergent dispenser may include a detergent container for storing detergent. The detergent dispenser may be configured to supply detergent into the tub during the water supply process. Water supplied through the water supply pipe may be mixed with the detergent by passing through the detergent dispenser. The water mixed with the detergent may be supplied into the tub. The term "detergent" is used as a collective term for pre-wash detergent, main wash detergent, fabric softener, bleach, etc., and the detergent container may be divided into a pre-wash detergent storage area, a main wash detergent storage area, a fabric softener storage area, and a bleach storage area.

[0056] The washing machine may include a drainage device configured to discharge water contained in a tub to the outside. The drainage device may include a drain pipe extending from the bottom of the tub to the outside of the housing, a drain valve provided in the drain pipe to open and close the drain pipe, and a pump provided on the drain pipe. The pump may pump water from the drain pipe to the outside of the housing.

[0057] The washing machine may include a control panel disposed on one side of the housing. The control panel may provide a user interface for the user to interact with the washing machine. The user interface may include at least one input interface and at least one output interface.

[0058] At least one input interface can convert sensory information received from a user into an electrical signal.

[0059] At least one input interface may include a power button, an operation button, a course selection dial (or course selection button), and a wash / rinse / spin setting button. At least one input interface may include, for example, a tact switch, a push switch, a slide switch, a toggle switch, a micro switch, a touch switch, a touchpad, a touchscreen, a jog dial, and / or a microphone.

[0060] At least one output interface can visually or audibly convey information related to the operation of the washing machine to the user.

[0061] For example, at least one output interface can convey information to the user regarding the washing course, the washing machine's operating time, and washing settings, rinse settings, and spin settings. Information regarding the operation of the washing machine may be output via a screen, indicator, voice, etc. At least one output interface may include, for example, a Liquid Crystal Display (LCD) panel, a Light Emitting Diode (LED) panel, a speaker, etc.

[0062] The washing machine may include a communication module for communicating with an external device via wired and / or wireless means.

[0063] The communication module may include at least one of a short-range communication module or a long-range communication module.

[0064] The communication module can transmit data to external devices (e.g., servers, user devices, and / or home appliances) or receive data from external devices. For example, the communication module can establish communication with servers and / or user devices and / or home appliances and transmit and receive various types of data.

[0065] To this end, the communication module may support the establishment of a direct (e.g., wired) communication channel or a wireless communication channel between external devices, and the performance of communication through the established communication channel. According to one embodiment, the communication module may include a wireless communication module (e.g., a cellular communication module, a short-range wireless communication module, or a GNSS (global navigation satellite system) communication module) or a wired communication module (e.g., a LAN (local area network) communication module, or a power line communication module). The corresponding communication module among these communication modules may communicate with an external device through a first network (e.g., a short-range communication network such as Bluetooth, WiFi (wireless fidelity) direct, or IrDA (infrared data association)) or a second network (e.g., a legacy cellular network, a 5G network, a next-generation communication network, the Internet, or a long-range communication network such as a computer network (e.g., a LAN or WAN). These various types of communication modules may be integrated into a single component (e.g., a single chip) or implemented as multiple separate components (e.g., multiple chips).

[0066] A short-range wireless communication module may include, but is not limited to, Bluetooth communication modules, BLE (Bluetooth Low Energy) communication modules, Near Field Communication modules, WLAN (Wi-Fi) communication modules, Zigbee communication modules, infrared (IrDA, infrared Data Association) communication modules, WFD (Wi-Fi Direct) communication modules, UWB (ultrawideband) communication modules, Ant+ communication modules, microwave (uWave) communication modules, etc.

[0067] The long-distance communication module may include a communication module that performs various types of long-distance communication and may include a mobile communication unit. The mobile communication unit transmits and receives wireless signals with at least one of a base station, an external terminal, and a server on a mobile communication network.

[0068] In one embodiment, the communication module can communicate with external devices, such as a server, a user device, or other home appliances, through a nearby access point (AP). The access point (AP) can connect a local area network (LAN) to which the washing machine or user device is connected to a wide area network (WAN) to which the server is connected. The washing machine or user device can be connected to the server through the wide area network (WAN). The control unit can control various components of the washing machine (e.g., drive motor, water supply valve). The control unit can control various components of the washing machine to perform at least one operation, including water supply, washing, rinsing, and / or spin-drying, according to user input. For example, the control unit can control the drive motor to adjust the rotation speed of the drum or control the water supply valve of the water supply device to supply water to the tub.

[0069] The control unit may include hardware such as a CPU or memory, and software such as a control program. For example, the control unit may include an algorithm for controlling the operation of components within the washing machine, at least one memory for storing data in the form of a program, and at least one processor for performing the aforementioned operation using data stored in at least one memory. The memory and the processor may each be implemented as separate chips. The processor may include one or more processor chips or one or more processing cores. The memory may include one or more memory chips or one or more memory blocks. Additionally, the memory and the processor may be implemented as a single chip.

[0070] When the drum of a washing machine rotates, so-called imbalance may occur, in which the center of rotation of the drum is deflected relative to the axis of rotation of the drum due to the weight and positional changes of the laundry contained inside the drum. This imbalance can cause noise, vibration, and resulting damage to the drum. To correct this imbalance, a liquid balancer that injects liquid, such as water, into the drum may be applied. For example, Japanese Patent Publication No. 2016-197 proposes a liquid balancer capable of adjusting weight by injecting water into the balancer according to the imbalance state. That is, in a drum-type washing machine, lifters (baffles) are attached at multiple locations on the inner surface of the drum to agitate the laundry, and liquid balancers are installed on the lifters. Specifically, a water supply ring unit is attached between the tub and the back surface of the drum, and water is injected into each lifter through the water supply ring unit. In this type of structure, it is necessary to install a space behind the drum inside the tub and attach a water supply ring unit there, and the water supply path increases depending on the number of lifters. To correct the imbalance, a certain amount of water supply is required, and the size of the water supply ring unit inevitably has to be larger. Consequently, the internal volume of the drum decreases, and the amount of laundry that can be processed in a single cycle may be reduced. Furthermore, the center of gravity deflected by the imbalance can be located in all directions relative to the drum's axis of rotation, but since the lifters are provided at limited specific locations on the inner surface of the drum, it may be difficult to properly correct the imbalance.

[0071] The present disclosure provides a washing machine employing a water-supplying liquid balancer capable of effectively correcting imbalance. However, the technical problems to be solved by the present disclosure are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

[0072] Hereinafter, embodiments of the washing machine of the present disclosure will be described with reference to the drawings. However, the following description is merely illustrative. In the following, the front-back, left-right, and up-down directions are based on the washing machine and are indicated by arrows in the drawings.

[0073] In addition, the term Unbalance (UB) used in this explanation refers to a state in which the distribution of laundry compressed by centrifugal force is skewed in the direction of rotation within the drum. Unbalance is caused by the center of gravity of the mass of laundry (laundry mass). When the laundry is not clumped together, the location of the center of gravity of the main mass of laundry becomes the location of the center of gravity of the laundry mass. The location of the center of gravity of the laundry mass corresponds to the location of unbalance. Furthermore, the mass of the laundry mass constituting the center of gravity corresponds to the amount of unbalance.

[0074] FIG. 1 is a schematic diagram of a washing machine (1) according to one embodiment of the present disclosure. The washing machine (1) of the present embodiment is a front-loading washing machine, so-called drum-type washing machine. The washing machine (1) of the present embodiment is a fully automatic washing machine capable of automatically performing a series of processes including washing, rinsing, and spin-drying. The washing machine (1) of the present embodiment may also be capable of drying.

[0075] Referring to FIG. 1, the washing machine (1) of the present embodiment may include a housing (2), a tub (3), a drum (4), a driving device (5), a water supply device (7), a drainage device (8), and a control unit (20). The washing machine (1) of the present embodiment may include an unbalance correction means (6) and an unbalance information acquisition means (Fig. 9: 9) so as to perform spin-drying efficiently and stably.

[0076] The housing (2) is a box-shaped container formed by panels, frames, etc., and forms the outer perimeter of the washing machine (1). A circular opening (2a) is provided on the front of the housing (2) for loading and unloading laundry. The opening (2a) is opened and closed by a door (2b) having a transparent window. An operating part (2c) including a switch that can be operated by a user may be installed in the upper area of ​​the opening (2a) of the housing (2).

[0077] A tub (3) is housed inside a housing (2). The tub (3) is a cylindrical water-retaining container having a tub opening (3a) and a bottom on the opposite side of the tub opening (3a). That is, the tub (3) is positioned horizontally so that the tub opening (3a) faces forward. The central axis (J) of the tub (3) is slightly inclined upward toward the front. The tub opening (3a) has a smaller diameter than the tub (3). The tub (3) is provided with an annular inner flange portion (3b) around the tub opening (3a).

[0078] By connecting the tub opening (3a) to the inlet (2a), the interior of the tub (3) communicates with the inlet (2a). For example, an elastically deformable ring-shaped diaphragm (10) (sealing member) may be interposed between the inlet (2a) and the tub opening (3a) of the tub (3). The diaphragm (10) may be attached to the tub (3) by being joined to the inner flange portion (3b). The diaphragm (10) blocks the gap between the inlet (2a) and the tub opening (3a).

[0079] The tub (3) is supported inside the housing (2) with an elastic member in between. For example, a plurality of dampers (11) are installed at the bottom of the housing (2), and the tub (3) is supported by the plurality of dampers (11). In addition, a plurality of coil springs (12) are installed at the top of the housing (2), and the tub (3) is suspended from the plurality of coil springs (12).

[0080] A water supply device (7), including a water supply pipe (7a) and a water supply valve (7b), is installed above the tub (3). The upstream end of the water supply pipe (7a) protrudes outside the washing machine (1) and is connected to a water source (e.g., a water tap) not shown. The downstream end of the water supply pipe (7a) is connected to the upper part of the tub (3).

[0081] A water supply section (61) is installed above the tub (3). The unbalance correction means (6) includes the water supply section (61). This will be described later.

[0082] A drain is installed at the bottom of the tub (3). The drain is connected to the suction port of the drain pump (8b) through the upstream drain pipe (8a). The downstream drain pipe (8c) is connected to the discharge port of the drain pump (8b). The downstream drain pipe (8c) is drawn out from the bottom of the housing (2) to the outside of the housing (2). A vibration sensor (13) for detecting vibration of the tub (3) is provided in the tub (3). The means for acquiring unbalance information (Fig. 9: 9) includes the vibration sensor (13).

[0083] The drum (4) is a cylindrical container with a bottom that is slightly smaller in diameter than the tub (3). The drum (4) is accommodated inside the tub (3) with its central axis (J) aligned with the tub (3). A circular drum opening (4a) is provided at the front end of the drum (4) (opposite the bottom) and facing the inlet (2a). Laundry is accommodated inside the drum (4) through the inlet (2a), the tub opening (3a), and the drum opening (4a).

[0084] The drum opening (4a) has a smaller diameter than the drum (4). The drum (4) is provided with an annular flange portion (4b) around the drum opening (4a). The flange portion (4b) faces the inner flange portion (3b) of the tub (3). In this embodiment, an annular trough portion (60) constituting the unbalance correction means (6) is attached to the flange portion (4b). The annular trough portion (60) will be described later.

[0085] A plurality of dewatering holes (4c) are formed along the entire circumference of the side of the drum (4) (only a portion is shown in FIG. 2). A stirring lifter (4d) is provided at multiple locations on the inner surface of the drum (4). The front end of the drum (4), i.e., the drum opening (4a), is rotatably supported by the tub opening (3a).

[0086] The driving device (5) may be positioned at the rear of the tub (3). The driving device (5) may include a motor (5a), a shaft (5b), etc. The shaft (5b) penetrates the bottom of the tub (3) from the rear to the front and is rotatably supported in the tub (3). One end of the shaft (5b) protrudes into the interior of the tub (3) and is fixed to the center of the bottom of the drum (4). Thus, the drum (4) is rotatably supported inside the tub (3).

[0087] The motor (5a) is installed at the rear of the bottom of the tub (3) and is connected coaxially with the shaft (5b). The drive unit (5) directly drives the drum (4) (so-called direct drive method). Accordingly, the drum (4) rotates around the central axis (J) by the drive of the motor (5a).

[0088] A rotation sensor (14) for detecting rotational speed and rotational position is installed on the motor (5a). A current sensor (15) for detecting the current flowing through the motor (5a) is installed on the inverter (5c) installed on the motor (5a). The rotation sensor (14) and the current sensor (15) constitute an unbalance information acquisition means (Fig. 9: 9).

[0089] The control unit (20) may be installed on the upper part of the housing (2). The control unit (20) comprehensively controls the operation of the washing machine (1), including the rotation of the motor (5a). As described above, the control unit (20) may include hardware such as one or more processors, such as a CPU, and one or more memories, as well as software such as a control program and various data. The control program and various data may be stored in one or more memories. The processor controls the washing machine (1) by running the program stored in the memory.

[0090] The control unit (20) controls the driving device (5) (e.g., motor (5a)), water supply valve (7b), drainage pump (8b), etc., according to instructions input from the operating unit (2c). Accordingly, the washing machine (1) performs a series of processes including a washing process, a rinsing process, and a spin-drying process. The control unit (20) also controls the unbalance correction means (6) in the spin-drying process.

[0091] Hereinafter, embodiments of the unbalance correction means (6) are described. During the spin-drying process, the drum (4) is rotated at high speed while containing the laundry. The type or material of the laundry may vary. Therefore, the weight or absorption capacity of the laundry before the spin-drying process may differ each time it is washed. In addition, the position of the laundry changes within the rotating drum (4).

[0092] During the spin-drying process, the laundry is pressed against the inner surface of the drum (4) by the action of centrifugal force caused by the rotation of the drum (4). At that time, due to the condition of the laundry being received, a so-called imbalance occurs in which the center of gravity of the rotating drum (4) is deflected relative to the central axis (J). As the spin-drying progresses, the centrifugal force increases and the position of the laundry stabilizes. And as the weight of the laundry decreases, the imbalance decreases and the rotation of the drum (4) stabilizes. However, abnormal vibration may occur due to the imbalance at a relatively low rotational speed stage until that happens.

[0093] To correct the imbalance, the washing machine (1) of the present embodiment is provided with a water-filling type imbalance correction means (6). The imbalance correction means (6) may include an annular trough portion (60) disposed on the outer edge portion of the drum (4), for example, the flange portion (4b) of the drum opening (4a), and a water-filling portion (61) for injecting water into the annular trough portion (60).

[0094] FIG. 2 is a schematic cross-sectional perspective view illustrating the tub (3) and the area around the water supply nozzle (61c). FIG. 3 is a schematic perspective view illustrating the annular trough (60) and the area around the water supply nozzle (61c). FIG. 4 is a detailed view of one embodiment of the annular trough (60). FIG. 5 is a Y1-Y1 cross-sectional view of the annular trough (60) illustrated in FIG. 4.

[0095] Referring to FIG. 1, the water supply unit (61) of the present embodiment is positioned on the upper part of the tub (3). The annular trough unit (60) of the present embodiment is positioned at the front end of the drum (4). The water supply unit (61) injects water into the upper part of the rotating annular trough unit (60). The water supply unit (61) may include a water supply valve (61a), a water supply pipe (61b), and a water supply nozzle (61c).

[0096] The water supply pipe (61b) branches off from the water supply pipe (7a) from a section upstream of the water supply valve (7b). An openable water supply valve (61a) is installed near the branching point of the water supply pipe (61b). When the water supply valve (61a) is opened, water is supplied to the water supply pipe (61b) by the water pressure of the water supply source.

[0097] The end portion of the water supply pipe (61b) can pass through the diaphragm (10) and be received inside the diaphragm (10). A water supply nozzle (61c) is provided at the end of the water supply pipe (61b). As shown in FIG. 2, the water supply nozzle (61c) can be fixed to the joint between the diaphragm (10) and the inner flange portion (3b) of the tub by a bracket. The end portion of the water supply pipe (61b) and the area around the water supply nozzle (61c) are covered by the diaphragm (10). By doing so, the water supply nozzle (61c) and other parts can be prevented from becoming dirty or accumulating due to the influence of dirty cleaning water accumulating inside the tub (3).

[0098] The water supply nozzle (61c) penetrates the inner flange portion (3b) of the diaphragm (10) and the tub (3), and the outermost portion of the water supply nozzle (61c), which is provided with an outlet, is located inside the tub (3) and faces the annular trough portion (60). Depending on the specifications of the washing machine (1), the water supply pipe (61b) and the water supply nozzle (61c) may not penetrate the diaphragm (10). The water supply nozzle (61c) directs water toward the annular trough portion (60) and sprays water in a straight line.

[0099] The annular trough (60) is a ring-shaped member as shown in FIG. 3. The annular trough (60) is installed on the flange portion (4b) of the drum (4) so ​​as to face the inner flange portion (3b) of the tub (3) as shown in FIG. 1. Referring to FIG. 3, the annular trough (60) includes an annular opening (64) provided on the inner side in the radial direction and a reservoir portion (65) provided on the outer side in the radial direction. The opening (64) is opened toward the direction of the central axis (J) of the annular trough (60) (forward in this embodiment).

[0100] Referring to FIG. 4, the annular trough (60) may have a cylindrical outer wall (60a) and an annular first side wall (60b) and second side wall (60c) that extend parallel inward in the radial direction from both sides in the direction of the central axis (J) of the outer wall (60a). By doing so, a water reservoir (65) having an inverted U-shaped cross-section facing outward in the radial direction is formed. The water reservoir (65) can store water by the action of centrifugal force.

[0101] A curved wall section (60d) that is gently curved inward toward the reservoir section (65) is provided at the inner end in the diameter direction of the first side wall section (60b). The second side wall section (60c) is connected to an inner wall section (60f) that is diametrically opposite to the outer wall section (60a) through a gently curved intermediate wall section (60e). The inner wall section (60f) is located diametrically inward from the end of the curved wall section (60d).

[0102] The side opposite to the second side wall (60c) of the inner wall portion (60f) is located slightly outward in the radial direction than the first side wall portion (60b). In this embodiment, an annular return wall portion (60g) extending outward in the radial direction is provided on the side opposite to the second side wall portion (60c) of the inner wall portion (60f). The end of the return wall portion (60g) is located inward in the radial direction than the end of the curved wall portion (60d). By this, an annular gap is formed between the return wall portion (60g) and the curved wall portion (60d). An opening (64) for receiving water from the water supply portion (61) is formed by this gap. In other words, the return wall portion (60g) is formed by extending inward in the radial direction from the edge inward in the radial direction of the opening (64). A plurality of drainage holes (66) are formed in the base portion adjacent to the inner circumferential wall portion (60f) of the return wall portion (60g). By the return wall portion (60g), leakage of water injected into the annular trough portion (60) during the rotation of the drum (4) can be suppressed. Additionally, by the drainage holes (66), residual water in the annular trough portion (60) can be prevented when the drum (4) is not rotating.

[0103] The interior of the annular trough (60) is divided into equal intervals in the circumferential direction by a plurality of partition walls (67), as shown in FIG. 5. A plurality of water storage cells (68) are formed by the water storage portion (65) being divided by the partition walls (67).

[0104] Referring to FIG. 4, the opening (64) is also partitioned by a partition wall (67). The end edge (67a) of the partition wall (67) facing the opening (64) is formed concavely inward so as not to protrude outward from the opening (64) (that is, from the first side wall (60b) and return wall (60g) of the annular trough (60). If the partition wall (67) protrudes outward from the opening (64), the water may hit the partition wall (67) and bounce outward when water is poured into the annular trough (60), thereby worsening the water supply efficiency. Therefore, by forming the partition wall (67) as shown in FIG. 4, the deterioration of water supply efficiency can be suppressed.

[0105] Additionally, as shown by the dashed line in FIG. 4, a connecting hole (69) may be provided in the partition wall (67) so that two adjacent water storage cells (68) can communicate with each other. By forming the connecting hole (69), water can be moved between two adjacent water storage cells (68). Thus, the difference in the amount of water stored in each water storage cell (68) can be reduced, allowing for balanced water storage in multiple water storage cells (68).

[0106] The reservoir (65) can be appropriately partitioned to ensure stable water storage performance of each water storage cell (68). FIG. 6 shows an example of partitioning the reservoir (65) into a plurality of water storage cells (68). In one embodiment, the reservoir (65) can be partitioned such that the cell center angle (θ1) of each water storage cell (68) is 10° or more and 30° or less. In other words, the cell center angle (θ1) of each water storage cell (68) can be 20° ± 10°.

[0107] As the annular trough (60) rotates while water is stored in each water storage cell (68), the water level (water level (Sw)) collected in each water storage cell (68) changes under the influence of centrifugal force and gravity. For example, referring to FIG. 6 (a) and (b), the tangential plane of each water storage cell (68) is called the reference plane (Rp). As the rotational speed of the drum (4) increases, the angle of inclination (θw) between the water level (Sw) and the reference plane (Rp) becomes smaller (Fig. 6 (a)), and as the rotational speed of the drum (4) decreases, the angle of inclination (θw) between the water level (Sw) and the reference plane (Rp) becomes larger (Fig. 6 (b)). If the angle of inclination (θw) of the water level (Sw) relative to the reference plane (Rp) is large, water leaks easily from the water storage cell (68) when full, so the amount of water that can be stored in the water storage cell (68) is reduced.

[0108] Also, referring to FIG. 6 (c) and (d), as the reservoir cell (68) becomes larger in the circumferential direction, the influence on the slope of the reservoir surface (Sw) increases, and the slope angle of the reservoir surface (Sw) increases (Fig. 6 (c)). As the reservoir cell (68) becomes smaller in the circumferential direction, the influence on the slope of the reservoir surface (Sw) decreases, and the slope angle of the reservoir surface (Sw) decreases (Fig. 6 (d)). That is, as the central angle (cell central angle (θ1)) of each reservoir cell (68) becomes smaller, the slope angle of the reservoir surface (Sw) of each reservoir cell (68) becomes smaller, and the amount of water that can be stored increases.

[0109] On the other hand, as the cell center angle (θ1) decreases, the capacity of each water storage cell (68) decreases, and at the same time, the number of partition walls (67) increases. That is, the total capacity of the annular trough section (60) decreases. The water storage section (65) can be appropriately partitioned in consideration of the above points. According to the inventors' findings, if the cell center angle (θ1) is set to be 20° or less and 10° or more (15°±5°), stable water storage performance of each water storage cell (68) can be secured. As an example, the cell center angle (θ1) can be set to 15°.

[0110] FIG. 7 illustrates an example of the arrangement relationship between the water spray nozzle (61c) and the annular trough (60). Referring to FIG. 7, the water spraying direction (Y3) of the water spray nozzle (61c) may be a direction tilted backward in a predetermined range with respect to the central axis (J) direction of the annular trough (60) in the rotation direction (Y2) of the drum (4). Additionally, the water spraying direction (Y3) of the water spray nozzle (61c) may be directed toward the opening (64) in a tilted state so as to approach the annular trough (60) in a predetermined range from the outside inward in the diameter direction of the annular trough (60).

[0111] Referring to the upper drawing of FIG. 7, the water storage cell (68) moves to the right by the rotation of the annular trough (60) as indicated by the arrow (Y2). The water supply direction (Y3) of the water supply nozzle (61c) is a direction tilted backward relative to the movement direction (Y2) of the water storage cell (68). As a result, water can be smoothly injected into the water storage cell (68) from the water supply nozzle (61c) without scattering water significantly.

[0112] In this embodiment, the cell center angle (θ1) is set to 15°. In this state, the range of the rearward inclination angle (θ2), viewed from the perspective of the rotational direction of the water supply direction (Y3) of the water supply nozzle (61c) which can smoothly supply water to the water storage cell (68) without being blocked by the partition wall (67), can be set to 30°±5° with respect to the direction of the center axis (J) of the annular trough part (60). As an embodiment, the rearward inclination angle (θ2) can be set to 30°.

[0113] Water (injected water) supplied from the water supply nozzle (61c) to the annular trough (60) collides with the inner wall surface of the annular trough (60). The annular trough (60) has a receiving surface (70) that receives the injected water. Depending on the angle of inclination in the diameter direction (water supply angle (θ3)) with respect to the receiving surface (70) in the water supply direction (Y3), the dispersion state of the injected water colliding with the receiving surface (70) changes. The water supply angle (θ3) can be set so that most of the water supplied from the water supply nozzle (61c) to the annular trough (60) is directed toward the reservoir (65), that is, to achieve high water supply efficiency.

[0114] FIG. 8 shows a simplified result of investigating the effect of the injection angle (θ3) of the injection water on the water surface (70) on the water flow by a simulation of a fluid dynamics-based division. The injection water that collides with the water surface (70) is dispersed. In FIG. 8, q1 and q2 represent the water advance side range and the water retreat side range, respectively, based on the point where the injection water collides with the water surface (70).

[0115] The table in FIG. 8 shows the ratio of water flow distributed to q1 and q2 according to the water supply angle (θ3). From the table in FIG. 8, it can be seen that when the water supply angle (θ3) becomes 45°, the ratio of q2 begins to increase relatively, and the water supply efficiency begins to deteriorate. Therefore, the water supply angle (θ3) can be set to 45° or less. As an example, the water supply angle (θ3) can be set to 45°.

[0116] The inner wall surface of the annular trough (60) has a continuous curved shape extending from the water level (70) toward the reservoir (65). Therefore, the injected water flowing into the water level (70) can smoothly flow toward the reservoir (65).

[0117] In addition, the water surface (70) always moves in conjunction with the rotation of the annular trough (60). Since the collision area of ​​the water surface (70) is also continuously offset, the dispersion of the injected water is mitigated. Therefore, the injected water flowing into the water surface (70) can be smoothly guided to the reservoir (65), thereby ensuring high water supply efficiency.

[0118] Hereinafter, embodiments of unbalance correction control are described. FIG. 9 illustrates a block diagram of a control unit (20) and its related components related to unbalance correction control. Referring to FIG. 9, the control unit (20) receives information from unbalance information acquisition means (Fig. 9: 9), such as a vibration sensor (13), a rotation sensor (14), and a current sensor (15), and outputs a control signal to a motor (5a) and a water supply valve (61a) based on the received information. The control unit (20) controls the water supply unit (61) during the execution of the dewatering process and adjusts the water supply state to the annular trough unit (60) according to the rotational speed of the drum (4). By doing so, the unbalance of the drum (4) is corrected (unbalance correction control).

[0119] For example, the control unit (20) may include an unbalanced (UB) state estimation unit (21), a water supply control unit (22), and a drive control unit (23) as functional components. The control unit (20) may further include an unbalanced state correction unit (24). The drive control unit (23) controls the drive of the motor (5a) so that the drum (4) rotates according to each process of the washing process. The water supply control unit (22) controls the opening and closing of the water supply valve (61a) when controlling the unbalanced state correction. The unbalanced state correction unit (24) will be described later.

[0120] The unbalance state estimation unit (21) estimates the location and amount of unbalance of the drum (4) based on information acquired by the unbalance information acquisition means (Fig. 9: 9) (e.g., vibration sensor (13), rotation sensor (14), current sensor (15)). The method for estimating the unbalance state can be appropriately selected from various known methods.

[0121] The water supply control unit (22) controls the water supply valve (61a) to supply water to the annular trough (60) according to the amount of the estimated unbalance, centering on the estimated unbalance location and the location of the annular trough (60) facing in the diameter direction of the drum (4). FIG. 10 is a schematic diagram of the drum (4) of the dehydration process viewed from the front, which is a diagram for explaining an example of unbalance correction control. Referring to FIG. 10, the drum (4) rotates clockwise about the central axis (J). The unbalance location (CG) and amount (W) of the unbalance of the laundry are estimated by the unbalance state estimation unit (21). The control unit (20) obtains the estimated unbalance location (CG) and the location facing in the diameter direction (unbalance opposing location (OP)). And the control unit (20) controls the water supply valve (61a) so that water is supplied to the annular trough (60) according to the amount of unbalance (W) in the range where the center angle is ±90° centered on the unbalanced opposing position (OP).

[0122] (Specific example of imbalance control during dehydration treatment)

[0123] When the washing and rinsing processes are finished and the rinsed water is drained from the tub (3), the dehydration process is initiated. FIG. 11 is a drawing for explaining an example of unbalance correction control, showing the rotational speed profile of the drum (4) of the dehydration process, the control profile of the water supply valve (61a), and the water supply amount profile.

[0124] Referring to FIG. 11, in the initial stage of the dehydration process, the drum (4) is rotated at a low rotational speed, and an imbalance is detected. To resolve the imbalance, a preliminary dehydration process may be performed in which the drum (4) is temporarily rotated at a high speed. Afterward, the rotational speed of the drum (4) is increased until it reaches a predetermined rotational speed (r2) of 1000 rpm or more (main dehydration process). After being maintained in that state for a certain period, it is decelerated, and the dehydration process is terminated.

[0125] In the unbalance correction control, the water supply process to the annular trough (60) is performed in the initial stage of the dehydration process when the rotational speed of the drum (4) is less than a predetermined rotational speed (r1). The rotational speed (r1) may be, for example, the resonant rotational speed of the washing machine (1).

[0126] A control unit (20), for example, a water supply control unit (22), controls the opening and closing of the water supply valve (61a) according to the rotational speed of the drum (4) to intermittently supply water (intermittent water) to the water supply range (R1) of the annular trough unit (60). For example, as shown in the middle drawing of FIG. 11, the water supply valve (61a) is opened at a timing when water can be supplied to the water supply range (R1) according to the rotation of the drum (4) (on operation of the water supply valve (61a)). The water supply valve (61a) is closed at a timing when water cannot be supplied to the water supply range (R1) (off operation of the water supply valve (61a)).

[0127] FIG. 12a shows the water supply state. FIG. 12b shows the drainage state. First, referring to FIG. 12a, as described above, straight water is injected into the annular trough (60) from the water supply nozzle (61c). The injected water is guided to the reservoir (65) through the water surface (70). Since the annular trough (60) rotates, it moves to the reservoir (65) and is stored by the action of centrifugal force as indicated by the arrow (Y4).

[0128] Since the injected water is distributed and stored in each water storage cell (68) having an optimized capacity, it can be stably stored in an appropriate range of the water storage section (65) with a sufficient amount of water and excellent water storage efficiency. In addition, as described above, the splashing of water can be suppressed according to the inclination angle range and the water spraying angle range of the water spraying nozzle (61c).

[0129] By intermittent watering controlled by the control unit (20), water can be selectively supplied within the watering range (R1) without being supplied outside the watering range (R2) as shown in the lower drawing of FIG. 11. By repeating intermittent watering, the amount of water stored in the watering range (R1) can be increased. When the amount of water stored in the watering range (R1) reaches the estimated amount of unbalance (W), the watering is stopped. By doing so, the deviation of the center of gravity of the drum (4) caused by the condition of the laundry can be offset, and the unbalance of the drum (4) can be corrected.

[0130] After that, the control unit (20) increases the rotational speed of the drum (4) to perform the main dewatering process. During the main dewatering process, the water stored in each water storage cell (68) is maintained by the action of centrifugal force. When the main dewatering process is finished, the motor (5a) is decelerated and the rotational speed of the drum (4) is reduced.

[0131] When the rotational speed of the drum (4) reaches a predetermined low rotational speed, the action of the centrifugal force weakens as shown in the upper drawing of FIG. 12b, and water is gradually drained from each water storage cell (68). That is, as the rotational speed of the drum (4) decreases, water is drained from the annular trough (60). In a washing machine (1) according to one embodiment of the present disclosure, a return wall (60g) is installed in the annular trough (60). Water in the water storage cells (68) flows along the second side wall (60c), the curved wall (60d), and the inner circumference wall (60f). Since the water is blocked by the return wall (60g), the water is not drained from the annular trough (60) all at once. Therefore, splashing caused by the drained water can be suppressed, and the spin-dried laundry can be prevented from getting wet again by the water drained from the annular trough (60). Since the return wall portion (60g) has a drain hole (66), water can be drained through the drain hole (66) as shown in the lower drawing of FIG. 12b. Thus, water can be drained without leaving any water in the annular trough portion (60).

[0132] Although a drum-type washing machine (1) has been described, the unbalance correction structure according to the present disclosure can also be applied to a top-loading washing machine, so-called top-loading washing machine. FIG. 13 is a schematic diagram of a washing machine (1B) according to one embodiment of the present disclosure. The washing machine (1B) of the present embodiment is a top-loading washing machine, so-called top-loading washing machine. Since the basic configuration of the washing machine (1B) is almost identical to that of the washing machine (1), the same reference numerals are used for components that have the same function as the washing machine (1) below, and the description thereof is simplified or omitted.

[0133] Referring to FIG. 13, in the case of the washing machine (1B), the inlet (2a) is installed on the upper surface of the housing (2), and the tub (3) and drum (4) are arranged vertically inside the housing (2). The annular trough (60) of the washing machine (1B) is arranged along the drum opening (4a) that is opened at the top of the drum (4). The water supply nozzle (61c) is positioned at the rear of the washing machine (1B), that is, near the water supply valve (61a).

[0134] FIG. 14 is an enlarged view of the annular trough portion (60) illustrated in FIG. 13. In the case of a drum washing machine (1B), the flange portion (4b) faces upward. An annular extension portion (80) extending upward from the flange portion (4b) is provided at the upper part of the drum (4). An annular trough portion (60) is installed on the annular extension portion (80).

[0135] The lower surface of the annular trough (60) faces the flange portion (4b) at a distance. At the boundary between the annular extension portion (80) and the flange portion (4b), a plurality of outer through holes (81) are formed that penetrate the annular extension portion (80) inwardly and outwardly (in the diameter direction). In the annular trough portion (60) of this embodiment, the annular wall portion (60g) is omitted. At the boundary between the second wall portion and the inner wall portion (60f), a plurality of inner through holes (82) are formed that penetrate the inner wall portion (60f) inwardly and outwardly (in the diameter direction).

[0136] The upper drawing of FIG. 14 illustrates the water supply state. As indicated by the arrow (Y3), water is injected into the annular trough (60) in a straight line from the water supply nozzle (61c). The injected water is guided to the reservoir (65) via the water surface (70). Because the annular trough (60) rotates, the injected water is stored in the reservoir cell (68) on the outer diameter side of the reservoir (65) due to the action of centrifugal force.

[0137] Water corresponding to the estimated position (CG) and amount (W) of the imbalance is injected into the annular trough (60) by intermittent water supply controlled by the control unit (20). By doing so, the bias of the center of gravity of the drum (4) caused by the condition of the laundry can be offset, thereby correcting the imbalance of the drum (4).

[0138] When the main dewatering process is finished, the motor (5a) is decelerated and the rotational speed of the drum (4) reaches a predetermined low rotational speed. As shown in the lower drawing of FIG. 14, when the action of centrifugal force weakens, the water collected in each water storage cell (68) by the action of gravity gradually collects at the bottom of the annular trough (60) and is drained from the annular trough (60) through the inner through hole (82).

[0139] The water drained from the annular trough (60) flows through the gap between the annular trough (60) and the flange (4b), and is drained from the drum (4) to the tub (3) through the outer through hole (81) of the annular extension (80). Thus, when the dewatering process is finished, the water can be drained without leaving any water in the annular trough (60).

[0140] FIG. 15 is a schematic diagram of a washing machine (1C) according to one embodiment of the present disclosure. The washing machine (1C) of the present embodiment is a drum-type washing machine. The washing machine (1C) of the present embodiment differs from the washing machine (1) shown in FIG. 1 in that an unbalance correction means (6), including an annular trough (60) and a water supply nozzle (61C), is installed not only at the front end of the drum (4) but also at the rear end. The unbalance correction means (6) installed at the rear end of the drum (4) is identical to the unbalance correction means (6) installed at the front end of the drum (4), except that the installation direction of the water supply nozzle (61C) and the annular trough (60) is symmetrical to that of the unbalance correction means (6) installed at the rear end of the drum (4). By installing the unbalance correction means (6) at the front end and the rear end of the drum (4) respectively in this way, the degree of freedom for unbalance correction control is increased. Therefore, unbalance correction can be performed more stably.

[0141] Although not illustrated in the drawing, in the case of the top-loading washing machine (1B) illustrated in FIG. 13, an unbalance correction means (6) can be added to the lower part of the drum (4). However, in this case, the installation direction of the water supply nozzle (61c) and the annular trough part (60) of the unbalance correction means (6) installed at the lower part of the drum (4) is the same as the installation direction of the water supply nozzle (61c) and the annular trough part (60) of the unbalance correction means (6) installed at the upper part of the drum (4).

[0142] In the following, embodiments of an unbalance correction control (improved unbalance correction control) capable of stably performing high-precision correction of unbalance are described.

[0143] As described above, in order to correct the imbalance, it is common practice to first estimate the imbalance state (location and amount of imbalance) by means of acquiring imbalance information (Fig. 9: 9). However, estimating the imbalance state is difficult and typically involves an estimation error.

[0144] Fig. 16 illustrates an example of unbalance correction control before improvement. Referring to Fig. 16, the thick black arrow indicates the water injection position. P UB α is the actual unbalanced position of the laundry. Ps represents the estimated unbalanced position. In this case, the actual unbalanced position (P UB ) and estimated unbalanced position (P S There is an error of about 40° between them. The degree of error may vary, but this degree of error is typical. Based on the estimated unbalanced position (Ps), the control unit (20) controls the water supply valve (61a) to supply water to the annular trough (60) according to the amount of unbalance (W) in a range where the center angle is ±90° centered on the unbalanced opposing position (OP), as shown in the upper drawing of FIG. 16. The result of continuing water supply according to the amount of unbalance estimated based on the estimated unbalanced position (Ps) is shown in the lower drawing of FIG. 16. That is, if the estimation of the unbalanced state includes an error, water is supplied to a range of the annular trough (60) that is offset from the actual unbalanced opposing position, so the unbalance cannot be properly corrected.

[0145] Taking these points into consideration, in the improved unbalance correction control, an unbalance position is searched by executing a search water multiple times in which at least one of the start position and end position of the water supply is different.

[0146] Referring to FIG. 9, in the case of a washing machine (1) that performs improved unbalance correction control, the control unit (20) further comprises an unbalance state correction unit (24). The washing machine (1) is equipped with a vibration sensor (13) that detects vibrations of the tub. The unbalance state correction unit (24) utilizes the vibration sensor (13). To correct the unbalance, the unbalance state correction unit (24) operates the water supply valve (61a) in cooperation with the water supply control unit (22). The unbalance state correction unit (24) performs multiple search water supplys in which at least one of the water supply start position and end position is different.

[0147] In one embodiment, an individual estimation process is performed to estimate the amount of unbalance in each of multiple search counts, and a selection process is performed to select the search count with the smallest estimated amount of unbalance among the multiple search counts as the dominant search count, and these individual estimation and selection processes are repeated until the unbalance state becomes stable.

[0148] The unbalanced state correction unit (24) performs a first advanced side search water supply (first advanced water supply) that supplies water to a predetermined range that is relatively advanced, and a first retard side search water supply (first retard water supply) that supplies water to a predetermined range that is relatively retarded (first search step). The advanced side refers to the front of the water supply range based on the estimated unbalanced opposing position (OP), and the retard side refers to the back of the water supply range based on the estimated unbalanced position. In the first search step, the amount of unbalanced for each of the first advanced side search water supply and the first retard side search water supply is estimated, and the one with the smaller estimated amount of unbalanced among the first advanced side search water supply and the first retard side search water supply is selected as the first superior search water supply (first selection processing). Then, based on the position of the first dominant search number, a second advanced-angle search number (second advanced-angle search number) is executed to administer within a predetermined range that is relatively advanced, and a second perceptual-angle search number (second perceptual search number) is executed to administer within a predetermined range that is relatively perceptual (second search step). In the second search step, the amount of imbalance for each of the second advanced-angle search number and the second perceptual-angle search number is estimated, and the one with the smaller estimated amount of imbalance among the second advanced-angle search number and the second perceptual-angle search number is selected as the second dominant search number (second selection process). If necessary, the third and fourth search steps may be repeated further.

[0149] FIG. 17a is a diagram showing the first search step in an example of improved unbalance correction control. FIG. 17b is a diagram showing the second search step in an example of improved unbalance correction control. FIG. 17c is a diagram showing the third search step in an example of improved unbalance correction control.

[0150] First, the unbalance state estimation unit (21) estimates the unbalance position and amount based on the information acquired by the unbalance information acquisition means (Fig. 9: 9). Then, as shown in the upper drawing of Fig. 17a, the water supply control unit (22), in cooperation with the unbalance state correction unit (24), controls the water supply valve (61a) to supply water to a range that is advanced by a predetermined angle (position shifted forward in the rotation direction) relative to the unbalance opposing position (OP) based on the result of estimating the unbalance position relative to the rotation direction of the drum (4) (first advanced water supply). The amount of water supplied in the first advanced water supply is a small amount, for example, 50g, which is sufficiently less than the amount of unbalance.

[0151] The water supply control unit (22) repeats the first advance water supply several to tens of times. Simultaneously with the first advance water supply, the unbalanced state correction unit (24) detects the vibration of the tub (3) using the vibration sensor (13). The vibration of the tub (3) is detected from the start to the end of the first advance water supply. Because water is supplied to the unbalanced opposing position (OP) side by the first advance water supply, the vibration of the tub (3) is reduced. The unbalanced state correction unit (24) calculates the amount of change in vibration (e.g., amplitude) (vibration change amount (△Va)) from the vibration detection data. For example, the difference between the amplitude at the start of the advance water supply and the end of the advance water supply can be defined as the vibration change amount (△Va).

[0152] As shown in the lower drawing of FIG. 17a, the water supply control unit (22) controls the water supply valve (61a) to supply water to a range that is angled (positioned backward in the direction of rotation) relative to the unbalanced opposing position (OP) based on the rotation direction of the drum (4) (first delayed water supply). The amount of water supplied in the first delayed water supply is also small.

[0153] The water supply control unit (22) repeats the first delayed water supply several to tens of times. Simultaneously with the first delayed water supply, the unbalanced state correction unit (24) detects the vibration of the tub (3). The vibration of the tub (3) is detected from the start to the end of the first delayed water supply. Since water is supplied to the unbalanced opposing position (OP) side by the first delayed water supply, the vibration of the tub (3) generally decreases. The unbalanced state correction unit (24) calculates the amount of change in vibration (e.g., amplitude) (vibration change amount (△Vr)) from the vibration detection data. For example, the difference between the amplitude at the start of the delayed water supply and the end of the delayed water supply can be defined as the vibration change amount (△Vr).

[0154] The unbalanced state correction unit (24) compares the magnitudes of the two calculated vibration change amounts (△Va) and (△Vr). Then, the search number with the smaller vibration change amount is selected as the dominant search number (selection processing). In the exemplary drawing, the first advanced angle number becomes the dominant search number. This series of processing corresponds to the first search step.

[0155] Next, as shown in the upper drawing of FIG. 17b, the water supply control unit (22) controls the water supply valve (61a) to supply water to a range that is advanced by a predetermined angle based on the rotation direction of the drum (4) for the water supply position of the superior search water selected in the first search step (second advanced water supply). The degree of advancement in the second advanced water supply is smaller than that in the first advanced water supply. The water supply control unit (22) repeats the second advanced water supply. And simultaneously with the second advanced water supply, the unbalanced state correction unit (24) detects vibration of the tub (3). The unbalanced state correction unit (24) calculates the second vibration change amount (△Va) from the vibration detection data.

[0156] As shown in the lower drawing of FIG. 17b, the water supply control unit (22) controls the water supply valve (61a) so that water is supplied to a range at a predetermined angle perceived relative to the rotation direction of the drum (4) for the water supply position of the superior search water supply (second retardation water supply). The water supply control unit (22) repeats the second retardation water supply. The degree of retardation in the second retardation water supply is smaller than that in the first retardation water supply. And simultaneously with the second retardation water supply, the unbalanced state correction unit (24) detects vibration of the tub (3). The unbalanced state correction unit (24) calculates the second vibration change amount (△Vr) from the vibration detection data.

[0157] The unbalanced state correction unit (24) compares the magnitudes of the two calculated second vibration change amounts (△Va) and (△Vr), and selects the search number with the smaller vibration change amount as the second dominant search number (selection processing). In the exemplary drawing, the second advanced angle number becomes the second dominant search number. This series of processing corresponds to the second search step.

[0158] Next, as illustrated in the upper drawing of FIG. 17c, the water supply control unit (22) controls the water supply valve (61a) so that water is supplied to a range that is advanced by a predetermined angle relative to the rotation direction of the drum (4) for the water supply position of the second superior search water supply (third advanced water supply). The degree of advancement is smaller for the third advanced water supply than for the second advanced water supply. The water supply control unit (22) repeats the third advanced water supply. Simultaneously with the third advanced water supply, the unbalanced state correction unit (24) detects vibration of the tub (3). The unbalanced state correction unit (24) calculates the third vibration change amount (△Va) from the vibration detection data.

[0159] As shown in the lower drawing of FIG. 17c, the water supply control unit (22) operates the water supply valve (61a) so that water is supplied to a range at a predetermined angle perceived relative to the rotation direction of the drum (4) for the water supply position of the second superior search water supply (third perceived water supply). The water supply control unit (22) repeats the third perceived water supply. The degree of perception is smaller for the third perceived water supply than for the second perceived water supply. Simultaneously with the third perceived water supply, the unbalanced state correction unit (24) detects vibration of the tub (3). The unbalanced state correction unit (24) calculates the third vibration change amount (△Vr) from the vibration detection data.

[0160] The unbalanced state correction unit (24) compares the magnitudes of the two calculated third vibration change amounts (△Va) and (△Vr), and selects the search number with the smaller vibration change amount as the third dominant search number (selection processing). In the exemplary drawing, the third advanced angle number becomes the third dominant search number.

[0161] As illustrated in FIGS. 17a, 17b, and 17c, as the search step progresses, the overlapping range of the advanced and retardant water streams increases. That is, the dominant search water stream approaches the unbalanced position. Considering the estimation error of the unbalanced position, a practically appropriate unbalanced position can be reached by performing three search steps. The unbalanced state correction unit (24) determines the center position of the water stream range of the third dominant search water stream as the actual unbalanced opposing position. The unbalanced state correction unit (24) terminates the search step.

[0162] After that, the unbalanced state correction unit (24) performs an unbalanced amount adjustment step. Specifically, after the repetition of the processing regarding the tan color water supply is finished, the unbalanced state correction unit (24) performs an adjustment water supply based on the last dominant search water supply position until the amount of unbalance begins to increase.

[0163] FIG. 18 illustrates an example of an unbalance amount adjustment step. Referring to FIG. 18, the water supply control unit (22) controls the water supply valve (61a) to supply water within the water supply range of the third superior search water supply (adjusted water supply). The amount of water supplied for the adjustment water supply may also be small, for example, about 50g. The water supply control unit (22) repeats the adjustment water supply. Simultaneously with the adjustment water supply, the unbalance state correction unit (24) detects the vibration (Vf) of the tub (3) from the start of the advance water supply.

[0164] Since water is supplied based on the actual unbalanced opposing position, the vibration (Vf) of the tub (3) decreases until the amount of water supplied balances the actual amount of unbalance. Then, when the amount of water supplied exceeds the state where it balances the actual amount of unbalance, the amount of unbalance increases in the opposite direction, and as a result, the vibration (Vf) of the tub (3) changes to an increase. Accordingly, the unbalanced state correction unit (24) detects an inflection point from the vibration detection data where the vibration (Vf) of the tub (3) begins to increase. The water supply control unit (22) terminates the adjustment water supply when it reaches the inflection point where the vibration (Vf) of the tub (3) begins to increase. By doing so, the amount of water supplied can be balanced with the actual unbalanced position and amount, and the unbalance can be resolved in an optimal state.

[0165] FIG. 19 illustrates an example of a change in the amount of unbalance in an unbalance correction process by an improved unbalance correction control based on actual measurements. Referring to FIG. 19, whenever search watering is performed, the watering position approaches the optimal watering position. As a result, the unbalanced position is corrected, and the amount of unbalance is gradually reduced. Then, through the adjustment watering at the optimal watering position, the amount of water and the amount of unbalance are balanced, and the amount of unbalance is resolved in an optimal state.

[0166] Figure 20 illustrates the relationship between the angular error between the estimated unbalanced position and the actual unbalanced position obtained by testing, and the angular error between the actual water supply position and the optimal water supply position. The dashed line represents the unbalanced correction control before improvement, and the solid line represents the improved unbalanced correction control.

[0167] Referring to Fig. 20, in the unbalance correction control prior to improvement, the angle error of the estimated unbalance position and the angle error of the water supply position are the same. In contrast, in the improved unbalance correction control, even if the angle error of the estimated unbalance position is around 60°, the water supply position can be corrected so that the angle error of the water supply position is approximately a few degrees. However, due to the influence of the spacing of the reservoir cells (e.g., 15°), the angle error of the water supply position tends to remain at approximately 15° even if the number of search water supply cycles is increased. Three cycles of the search water supply stage are efficient.

[0168] Figure 21 illustrates the relationship between the angular error between the estimated unbalance position and the actual unbalance position obtained by the test, and the amount of residual unbalance after unbalance correction control. The dashed line represents the unbalance correction control before improvement, and the solid line represents the improved unbalance correction control. In the test, the initial amount of unbalance was 700g, and 700g was supplied by unbalance correction control.

[0169] Referring to Fig. 21, in the unbalance correction control before improvement, the amount of residual unbalance increases in proportion to the estimation error of the unbalance position. In contrast, in the improved unbalance correction control, it can be seen that the amount of unbalance is resolved in an optimal state up to an estimation error of the unbalance position of around 60°. Therefore, according to the improved unbalance correction control, unbalance can be resolved over a wide range, thereby ensuring robustness.

[0170] FIGS. 22a and FIGS. 22b are flowcharts showing an example of improved unbalance correction control performed by a control unit (20). Referring to FIGS. 22a and FIGS. 22b, the control unit (20) reads various measurement data (step S1) and estimates the unbalance position (amount) (step S2).

[0171] When the unbalanced position (amount) is estimated, the control unit (20) initiates advance water injection based on the estimation result (step S3). The control unit (20) detects vibration of the tub (3) simultaneously with the advance water injection. When the advance water injection is completed, the control unit (20) calculates the vibration change amount (△Va) (steps S4, S5). Subsequently, the control unit (20) initiates retard water injection (step S6). When the retard water injection is completed, the control unit (20) calculates the vibration change amount (△Vr) (steps S7, S8). The control unit (20) compares the magnitudes of the two vibration change amounts (△Va) and (△Vr) (step S9).

[0172] As a result, if the vibration change amount (△Va) of the advance water supply is smaller than the vibration change amount (△Vr) of the retard water supply (No in step S9), the control unit (20) determines that there is an actual unbalanced opposing position on the advance side and selects the advance side as the water supply position (step S10). Conversely, if the vibration change amount (△Vr) of the retard water supply is smaller than the vibration change amount (△Va) of the advance water supply, the control unit (20) determines that there is an actual unbalanced opposing position on the retard side and selects the retard side as the water supply position (step S11).

[0173] The control unit (20) determines whether the determination of the water supply location has been completed (step S12). For example, if the search step is set to 3 times, the determination of the water supply location can be determined by whether the search water supply to determine the water supply location has been performed 3 times. For example, the determination of the water supply location can also be determined by whether the vibration change amount (△Va and / or △Vr) of the tub (3) has reached a predetermined determination value (target vibration change amount).

[0174] The control unit (20) repeats a series of processes corresponding to the search phase until the determination of the water supply location is completed (steps S3 to S11). Meanwhile, when it is determined that the location determination is completed, the control unit (20) starts the adjustment water supply (step S13).

[0175] The control unit (20) determines whether the vibration (Vf) of the tub (3) has started to increase (step S14). If it is determined that the vibration (Vf) of the tub (3) has started to increase, the adjustment water supply is terminated (step S15). By doing so, the improved unbalance correction control is terminated. The control unit (20) increases the rotational speed of the tub (3) and proceeds to the main dewatering process.

[0176] The washing machine according to the present invention is not limited to the embodiments described above and may include various configurations not mentioned in the description of the embodiments described above. For example, the water supply unit (61) of the washing machine (1) may be positioned at the bottom of the tub (3) to inject water into the bottom of the rotating annular trough unit (60). The water supply unit (61) of the washing machine (1) may also be positioned at the side of the tub (3).

[0177] In the above-described embodiments, water is supplied to the annular trough (60) using an external water source having a predetermined water pressure, but is not limited thereto. For example, a water supply pump (not shown) may be installed in the housing (2), and water may be supplied to the annular trough (60) using the water pressure of the water supply pump.

[0178] In the aforementioned embodiments, a structure in which the annular trough (60) is installed at the front end (upper end in the case of a top-loading washing machine (1B)) or at both the front end (upper end in the case of a top-loading washing machine (1B)) and the rear end (lower end in the case of a top-loading washing machine (1B)) of the drum (4) is exemplified, but is not limited thereto. The annular trough (60) may be installed only at the rear end (lower end in the case of a top-loading washing machine (1B)) of the drum (4).

[0179] Dehydration treatment is generally performed at the final stage of the washing process, but it may also be performed during the rinsing process. The present disclosure may also be applied to dehydration treatment other than the final stage.

[0180] In the improved unbalance correction control, estimation of the unbalance state is not essential. Even without estimating the unbalance state, the unbalance location can be identified by the number of searches and selection processing, that is, by repeating the search step. According to this, the means for acquiring unbalance information (Fig. 9: 9) becomes unnecessary, which offers a cost advantage. However, compared to the case where the estimation of the unbalance state is performed first, the number of searches may increase.

[0181] For example, the optimal number of search steps may be three, but depending on the specifications of the washing machine, it may be two or four or more. In addition, the end of the search is not defined by the number of times the search step is performed, but a predetermined target value for determining the end of the search (e.g., a target value for the amount of change in vibration of the tub (3)) may be set, and the search step may be repeated until, for example, the amount of change in vibration of the tub (3) reaches the set target value. The number of advanced and retardant water sprays is not limited to two. If the water spray range is misaligned in the rotational direction, the number of advanced and retardant water sprays may be three or more.

[0182] A washing machine according to one aspect of the present disclosure is a washing machine capable of performing a spin-drying process, comprising: a housing; a tub capable of storing water that is elastically supported inside the housing; a drum that is rotatably installed inside the tub and receives laundry; a driving device for rotating the drum; an unbalance correction means comprising an annular trough portion disposed at the outer edge portion of the drum and a water supply portion for injecting water into the annular trough portion, for correcting an unbalance of the drum caused by the receiving state of the laundry; and a control unit for controlling the driving device and the unbalance correction means to correct the unbalance of the drum by adjusting the water supply state to the annular trough portion according to the rotational speed of the rotating drum during the execution of the spin-drying process.

[0183] According to the aforementioned embodiment of the washing machine, when an imbalance occurs in the drum due to the unevenness of the laundry, an optimal weight of water corresponding to the amount of imbalance can be supplied to the annular trough. Furthermore, since the imbalance of the drum is corrected by adjusting the water supply state to the annular trough according to the drum's rotation speed, water can be supplied to the appropriate part of the annular trough corresponding to the location of the drum's imbalance, thereby effectively correcting the drum's imbalance. Since the annular trough is provided at the outer edge of the drum, it does not affect the internal volume of the drum. Therefore, the washing capacity of the washing machine is hardly reduced or is reduced only slightly, thereby improving the performance of the washing machine.

[0184] In one embodiment, the washing machine may include an unbalance information acquisition means for acquiring information regarding the unbalance. The control unit may include an unbalance state estimation unit that estimates the location and amount of the unbalance of the drum based on the information acquired by the unbalance information acquisition means. The control unit may operate the water supply unit to supply water according to the estimated amount of the unbalance at the location of the annular trough unit facing the estimated location of the unbalance in the diameter direction of the drum. Accordingly, the unbalance of the drum can be effectively corrected because an appropriate amount of water can be injected into the annular trough unit to offset the unbalance with respect to the estimated location and amount of the unbalance.

[0185] In one embodiment, the control unit may include an unbalance state correction unit that operates the water supply unit to correct the unbalance. The unbalance state correction unit may execute search water supply multiple times in which at least one of the water supply start position and end position is different. Accordingly, the actual unbalance position can be searched, allowing water to be supplied to the annular trough in an optimal state, and the unbalance can be stably resolved with high precision.

[0186] In one embodiment, the unbalance state correction unit executes a search step comprising an individual estimation process for estimating the amount of unbalance in each of the plurality of search numbers and a selection process for selecting the one with the smallest estimated amount of unbalance among the plurality of search numbers as the dominant search number, and can repeat the search step. According to this, the optimal number position can be approached each time the individual estimation process and the selection process are repeated, and the unbalance can be stably resolved with high precision.

[0187] In one embodiment, the unbalance state correction unit executes a first search step that executes a first advance-side search water supply that supplies water to a predetermined range of the annular trough portion that is relatively advanced based on the rotation direction of the drum, and a first retardation-side search water supply that supplies water to a predetermined range of the annular trough portion that is relatively retarded based on the rotation direction of the drum; in the first search step, it estimates the amount of unbalance for each of the first advance-side search water supply and the first retardation-side search water supply, and executes a first selection process that selects the one with the smaller estimated amount of unbalance among the first advance-side search water supply and the first retardation-side search water supply as the first dominant search water supply; and executes a second search step that executes a second advance-side search water supply that supplies water to a predetermined range that is relatively advanced based on the position of the first dominant search water supply, and a second retardation-side search water supply that supplies water to a predetermined range that is relatively retarded. In the second search step, the amount of imbalance for each of the second advanced-angle search water and the second retardation-angle search water is estimated, and the second selection process is executed to select the one with the smaller estimated amount of imbalance between the second advanced-angle search water and the second retardation-angle search water as the second dominant search water; and the search step may be repeated further if necessary. Accordingly, by repeating the search step, the optimal water position can be approached further, and the imbalance can be resolved stably with high precision.

[0188] In one embodiment, after the repetition of the search step is terminated, the unbalance state correction unit may perform an adjustment watering based on the position of the last dominant search watering until the amount of unbalance begins to increase. By doing so, the amount of water to be poured at the optimal watering position corresponding to the actual unbalanced position found can be increased, and the amount of water to be poured can be balanced with the actual amount of unbalance, thereby enabling the unbalance to be resolved stably with high precision.

[0189] In one embodiment, the annular trough may include an opening for receiving water from the water supply section and a water reservoir installed radially outward from the opening to store water injected through the opening by the action of centrifugal force. Accordingly, a compact annular trough capable of effectively correcting imbalance with a simple structure can be realized.

[0190] In one embodiment, the opening is opened in the direction of the central axis of the annular trough, and an annular return wall extending inward in the diametrical direction may be provided at the inner edge of the opening. Accordingly, leakage from the annular trough can be suppressed, thereby preventing the laundry contained inside the drum from getting wet during spin drying.

[0191] In one embodiment, the direction of water injection from the water supply section into the opening may be inclined backward relative to the central axis direction of the annular trough section with respect to the rotational direction of the drum. Accordingly, water can be supplied to the annular trough section without significant splashing.

[0192] In one embodiment, the annular trough portion is provided with a receiving surface for receiving injected water, and the water injection direction of the water injected from the water injection portion into the opening may have a water injection angle of 45 degrees or less with respect to the receiving surface. Accordingly, high water injection efficiency can be secured, so that the imbalance can be effectively corrected without adversely affecting the dewatering process.

[0193] In one embodiment, the annular trough may be provided with a plurality of water storage cells partitioned by a plurality of partition walls in the circumferential direction. A communication hole may be formed in the plurality of partition walls so that the plurality of water storage cells communicate with each other. Accordingly, since water can be stored in a predetermined range in the circumferential direction of the annular trough, water storage can be easily achieved, and imbalance can be corrected more effectively. Since water can move between water storage cells through the communication hole, even if there is a difference in the water storage volume of the plurality of water storage cells, the difference can be reduced. Furthermore, since water can freely move between each water storage cell depending on the location of the imbalance, the imbalance can be corrected even more effectively.

[0194] In one embodiment, the end edge of the partition wall facing the opening may not protrude outside the opening. Accordingly, it is possible to prevent water from splashing out during water supply and thus reducing water supply efficiency.

[0195] In one embodiment, a laundry inlet is installed on the front of the housing, and the water supply unit is positioned on the upper part of the tub to inject water into the rotating annular trough. As an example of application to a so-called drum-type washing machine, the water supply unit can be configured compactly using existing piping.

[0196] In one embodiment, the annular trough portion is positioned along a drum opening that is open opposite the inlet at the front end of the drum, and the area around the water supply nozzle of the water supply portion may be covered by a sealing member that blocks the gap between the inlet and the tub opening of the tub. Accordingly, it is possible to prevent dirty washing water inside the tub from splashing and adhering to the water supply nozzle portion.

[0197] In one embodiment, a laundry inlet is installed on the upper surface of the housing, and the annular trough may be arranged along a drum opening that is opened at the top of the drum. As an example of application to a so-called top-loading washing machine, the imbalance can be effectively corrected while sufficiently securing the internal volume of the drum.

[0198] As described above, according to the present disclosure, the imbalance of the drum can be effectively corrected by using a liquid balancer with water, and the performance of the washing machine can be improved. However, the technical effects intended to be achieved in this document are not limited to the technical effects mentioned above, and other technical effects not mentioned will be clearly understood by those skilled in the art to which this disclosure belongs from the description in this document.

[0199] As described above, although the washing machine of the present disclosure has been explained by limited embodiments and drawings, the present disclosure is not limited to the above embodiments and various modifications are possible within the scope without departing from the spirit thereof.

Claims

1. As a washing machine capable of performing spin drying, Housing(2); A water-retaining tub (3) elastically supported inside the above housing (2); A drum (4) that is rotatably installed inside the above tub and accommodates laundry; A driving device (5) for rotating the above drum; An unbalance correction means (6) for correcting the unbalance of the drum caused by the receiving state of the laundry, comprising an annular trough portion (60) disposed on the outer edge portion of the drum and a water injection portion (61) for injecting water into the annular trough portion; A washing machine comprising: a control unit (20) that controls the driving device and the unbalance correction means to correct the unbalance of the drum by adjusting the water supply state to the annular trough section according to the rotational speed of the rotating drum during the execution of the above dehydration process.

2. In Paragraph 1, It includes an unbalance information acquisition means (9) for acquiring information regarding unbalance; The above control unit is provided with an unbalance state estimation unit (21) that estimates the position and amount of unbalance of the drum based on information acquired by the unbalance information acquisition means. A washing machine in which the control unit operates the water supply unit to supply water according to the amount of the estimated unbalance at the position of the annular trough portion facing the diameter direction of the drum with respect to the estimated position of the unbalance.

3. In Paragraph 1 or 2, The above control unit includes an unbalanced state correction unit (24) that operates the water supply unit to correct the unbalance, and A washing machine in which the above-mentioned unbalanced state correction unit performs multiple search waters, at least one of the water start position and end position.

4. In Paragraph 3, The above-mentioned unbalanced state correction unit executes a search step including individual estimation processing for estimating the amount of unbalance in each of the plurality of search weeks, and selection processing for selecting the one with the smallest estimated amount of unbalance among the plurality of search weeks as the dominant search week. A washing machine that repeats the above search step.

5. In Paragraph 4, The above-mentioned unbalanced state correction unit is, A first search step is executed to perform a first advance-side search watering that performs watering in a predetermined range of the annular trough portion that is relatively advanced based on the rotation direction of the drum, and a first retardation-side search watering that performs watering in a predetermined range of the annular trough portion that is relatively retarded based on the rotation direction of the drum. In the first search step, the amount of imbalance between the first advanced search number and the first retardation search number is estimated, and the first selection process is executed to select the one with the smaller estimated amount of imbalance between the first advanced search number and the first retardation search number as the first dominant search number. A second search step is executed to perform a second advance-side search water supply that performs a search water supply in a predetermined range that is relatively advanced based on the position of the first superior search water supply, and a second perception-side search water supply that performs a search water supply in a predetermined range that is relatively perceived. In the second search step, the amount of imbalance between the second advanced search number and the second retardation search number is estimated, and the second selection process is executed to select the one with the smaller estimated amount of imbalance between the second advanced search number and the second retardation search number as the second dominant search number. A washing machine that repeats the above search steps further as needed.

6. In Paragraph 4 or 5, After the repetition of the above search step is terminated, the unbalanced state correction unit performs an adjustment watering process until the amount of unbalance begins to increase based on the position of the last dominant search watering.

7. In any one of paragraphs 1 through 6, The above-mentioned annular trough comprises an opening (64) for receiving water from the water supply section and a water reservoir (65) installed on the outer side in the radial direction with respect to the opening (64) for storing water injected through the opening by the action of centrifugal force.

8. In Paragraph 7, The above opening is opened in the direction of the central axis (J) of the annular trough, and A washing machine having an annular return wall (60g) extended inward in the radial direction at the inner edge of the opening in the radial direction.

9. In Paragraph 7 or 8, A washing machine in which the direction of water injection (Y3) from the water injection section to the opening is tilted backward relative to the central axis (J) of the annular trough section with respect to the rotational direction of the drum.

10. In any one of paragraphs 7 through 9, The above-mentioned annular trough is equipped with a receiving surface that receives injected water, and A washing machine in which the water injection direction (Y3) of water injected from the water injection section into the opening forms a water injection angle with the water surface of 45 degrees or less.

11. In any one of paragraphs 7 through 10, The above-mentioned annular trough section is provided with a plurality of water storage cells (68) partitioned by a plurality of partition walls (67) in the circumferential direction, and A washing machine having communication holes (69) formed in the plurality of partition walls so that the plurality of water storage cells communicate with each other.

12. In Paragraph 11, A washing machine in which the end edge (67a) of the partition wall facing the opening does not protrude outside the opening.

13. In any one of paragraphs 1 through 12, A laundry input port (2a) is installed on the front of the housing, and A washing machine in which the above-mentioned water injection part is positioned on the upper part of the tub and injects water into the rotating annular trough.

14. In Paragraph 13, The above-mentioned annular trough portion is arranged along the drum opening (4a) which is opened opposite the input port at the front end of the drum, and A washing machine in which the area around the water supply nozzle of the above-mentioned water supply section is covered by a sealing member that blocks the gap between the above-mentioned inlet and the tub opening (3a) of the above-mentioned tub.

15. In any one of paragraphs 1 through 12, A laundry input port (2a) is installed on the upper surface of the housing, and A washing machine in which the above-mentioned annular trough is positioned along the drum opening (4a) that is opened at the top of the drum.

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