Drum-type washing machine

Abstract

The present invention provides a drum-type washing machine that can distinguish between abnormalities occurring during water supply to the outer tub and abnormalities in water level detection, and notify the user accordingly. [Solution] In a drum-type washing machine 1, if the control unit 201 determines that the water level in the outer tub has changed since before the start of water supply, it causes the display unit 204 to issue a first notification corresponding to a water supply abnormality. If the control unit 201 determines that the water level in the outer tub has not changed since before the start of water supply, it rotates the drum to detect the load applied to the drum and determines whether the load has changed since before the start of water supply to the outer tub. If the control unit 201 determines that the load applied to the drum has not changed since before the start of water supply, it causes the display unit 204 to issue a first notification. If the control unit 201 determines that the load applied to the drum has changed since before the start of water supply, it causes the display unit 204 to issue a second notification corresponding to a water level detection abnormality.

Description

Technical Field

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

Background Art

[0002] A drum washing machine is described in Patent Document 1, in which water is supplied into an outer tub in which a drum is disposed by opening a first water supply valve, and when the water level in the outer tub detected by a water level detection means does not reach a first set water level after a first predetermined time has elapsed, an abnormality display is performed by a display means.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above drum washing machine, in addition to the case where a water supply abnormality occurs due to an abnormality in the water supply system or the drainage system and water does not accumulate normally in the outer tub, even when the water level in the outer tub actually reaches the first set water level within the first predetermined time but a water level detection abnormality occurs where the reach to the first set water level is not detected due to a failure of the water level detection means or the like, an abnormality display is performed by the display means.

[0005] Therefore, it is difficult for the user to know whether a water supply abnormality or a water level detection abnormality has occurred in the above drum washing machine.

[0006] The present invention has been made in view of such problems, and an object thereof is to provide a drum washing machine capable of distinguishing an abnormality occurring during water supply to the outer tub into a water supply abnormality and a water level detection abnormality and notifying the user.

Means for Solving the Problems

[0007] A drum-type washing machine according to the main aspect of the present invention comprises an outer tub disposed within a casing, a drum rotatably disposed within the outer tub around a horizontal axis or a rotation axis inclined with respect to the horizontal direction, and which holds laundry, a drive motor for rotating the drum, a water supply device for supplying water into the outer tub, a water level detection unit for detecting the water level in the outer tub, a notification unit, and a control unit. Here, the control unit, after rotating the drum with the drive motor and detecting the load applied to the drum, starts supplying water to the outer tub using the water supply device, and if it determines that a first time limit has elapsed since the start of water supply but before the water level in the outer tub reaches a predetermined water level such that the drum is submerged in the water, it determines whether the water level in the outer tub detected by the water level detection unit at the time the first time limit has elapsed has changed from before the start of water supply. If the control unit determines that the water level in the outer tank has changed since before the start of water supply, it causes the notification unit to issue a first notification corresponding to a water supply abnormality in which water is not properly filling the outer tank. If the control unit determines that the water level in the outer tank has not changed since before the start of water supply, it rotates the drum to detect the load applied to the drum and determines whether the load has changed since before the start of water supply to the outer tank. If the control unit determines that the load applied to the drum has not changed since before the start of water supply, it causes the notification unit to issue the first notification. If the control unit determines that the load applied to the drum has changed since before the start of water supply, it causes the notification unit to issue a second notification corresponding to a water level detection abnormality in which the water level detection unit is not properly detecting the water level in the outer tank.

[0008] For example, the control unit can determine that there is no change in water level if the difference between the water level detected after the first time limit has elapsed and the water level detected before the start of water supply is smaller than a predetermined range that takes detection errors into account. Furthermore, the control unit can determine that there is no change in load if the difference between the load on the drum detected after the first time limit has elapsed and the load on the drum detected before the start of water supply is smaller than a predetermined range that takes detection errors into account.

[0009] According to the drum-type washing machine of this embodiment, abnormalities that occur when supplying water to the outer tub can be distinguished and notified to the user as water supply abnormalities and water level detection abnormalities.

[0010] In the drum-type washing machine according to this embodiment, water is supplied to the outer tub by the water supply device until a set water level is reached, and the specified water level may be set to a water level lower than the set water level. In this case, if the control unit determines that the water level in the outer tub has reached the specified water level before the first time limit has elapsed, it rotates the drum with the water supply to the outer tub stopped to detect the load applied to the drum, and then resumes the water supply to the outer tub. If the water level detection unit does not detect that the water level in the outer tub has reached the set water level even after the second time limit has elapsed since the water supply was resumed, the control unit determines whether the water level in the outer tub detected by the water level detection unit at the time the second time limit has elapsed has changed from the time it was determined that the specified water level had been reached. If the control unit determines that the water level in the outer tank has changed since the determination that it has reached the specified water level, it causes the notification unit to issue the first notification. If the control unit determines that the water level in the outer tank has not changed since the determination that it has reached the specified water level, it rotates the drum to detect the load applied to the drum and determines whether the load has changed since the determination that it has reached the specified water level. If the control unit determines that the load applied to the drum has not changed since the determination that it has reached the specified water level, it causes the notification unit to issue the first notification. If the control unit determines that the load applied to the drum has changed since the determination that it has reached the specified water level, it causes the notification unit to issue the second notification.

[0011] For example, the control unit can determine that there has been no change in water level if the difference between the water level detected when the second time limit has elapsed and the water level detected when it is determined that the specified water level has been reached is smaller than a predetermined range that takes detection errors into account. Furthermore, the control unit can determine that there has been no change in load if the difference between the load on the drum detected when the second time limit has elapsed and the load on the drum detected when it is determined that the specified water level has been reached is smaller than a predetermined range that takes detection errors into account.

[0012] With the above configuration, it is possible to determine whether a water supply abnormality or a water level detection abnormality has occurred in two stages: the stage when water is supplied to a specified water level lower than the set water level, and the stage when water is supplied from the specified water level to the set water level, and to inform the user of which abnormality has occurred.

[0013] In the drum-type washing machine according to this embodiment, a configuration may be adopted that further includes an openable and closable door covering the loading opening provided in the housing, a door lock device that locks the door to prevent it from opening, and a drain unit that drains water from the outer tub. In this case, when the control unit causes the notification unit to give the second notification, it releases the lock on the door by the door lock device, and before releasing the lock on the door, it drains water from the outer tub using the drain unit.

[0014] With the above configuration, when a water level detection error occurs and there is little prospect of restarting the washing cycle, the user can open the door and remove the laundry from inside the drum. Moreover, when the door lock is released, the water level in the outer tub can be made lower than the bottom edge of the loading opening, thus preventing water from leaking from the loading opening when the door is opened. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a drum-type washing machine that can distinguish between abnormalities that occur when supplying water to the outer tub and abnormalities in water supply and notify the user accordingly.

[0016] The effects or significance of the present invention will become clearer from the description of the embodiments shown below. However, the following embodiments are merely examples for implementing the present invention, and the present invention is not limited to those described in the following embodiments in any way.

Brief Description of the Drawings

[0017] [Figure 1] FIG. 1 is a side cross-sectional view showing the configuration of a drum washing machine according to an embodiment. [Figure 2] FIG. 2 is a front cross-sectional view showing an outer tub to which a water level detection unit is attached according to an embodiment. [Figure 3] FIG. 3 is a block diagram showing the configuration of a drum washing machine according to an embodiment. [Figure 4] FIG. 4 is a flowchart showing control processing executed by a control unit in a water supply process according to an embodiment. [Figure 5] FIG. 5 is a flowchart showing control processing executed by a control unit in a water supply process according to an embodiment.

Embodiments for Implementing the Invention

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0019] FIG. 1 is a side cross-sectional view showing the configuration of a drum washing machine 1. FIG. 2 is a front cross-sectional view showing an outer tub 20 to which a water level detection unit 60 is attached.

[0020] The drum washing machine 1 includes a rectangular housing 10. A circular inlet 11 for loading laundry is formed on the front surface of the housing 10. The inlet 11 is covered by a door 12 that can be opened and closed.

[0021] Inside the housing 10, an outer tub 20 having a substantially cylindrical shape is disposed. The outer tub 20 is elastically supported by a plurality of dampers 21 and springs 22. Inside the outer tub 20, a horizontal-axis drum 23 is rotatably disposed. The drum 23 rotates around a horizontal axis. The drum 23 has a circular opening 23a on its front surface. The drum 23 may rotate around a rotation axis inclined with respect to the horizontal direction.

[0022] The outer tub 20 has a circular opening 20a in front of the opening 23a of the drum 23. The peripheral edge of the opening 20a of the outer tub 20 and the peripheral edge of the inlet 11 of the housing 10 are connected by an annular door packing 24 made of an elastic material. Also, the peripheral surface of the closed door 12 contacts the door packing 24, and the space between the inlet 11 and the door 12 is sealed against water.

[0023] On the inner peripheral surface of the drum 23, a large number of dehydration holes 23b are formed. Also, on the inner peripheral surface of the drum 23, a plurality of baffles 25 having a substantially triangular prism shape are provided at equal intervals in the circumferential direction.

[0024] Behind the outer tub 20, a drive motor 30 for generating a torque for rotating the drum 23 is disposed. The drive motor 30 is, for example, an outer-rotor type DC brushless motor. During the washing process and the rinsing process, the drive motor 30 rotates the drum 23 at a rotational speed at which the centrifugal force applied to the laundry in the drum 23 is smaller than the gravity and the laundry tumbles. On the other hand, during the dehydration process, the drive motor 30 rotates the drum 23 at a rotational speed at which the centrifugal force applied to the laundry in the drum 23 is much larger than the gravity and the laundry adheres to the inner peripheral surface of the drum 23.

[0025] A tubular drain port 20b is provided at the bottom of the outer tank 20. A drain section 40 for draining water from inside the outer tank 20 is connected to the drain port 20b. The drain section 40 consists of a drain valve 41, a drain hose 42, and a drain filter 43. The drain filter 43 is connected to the lower end of the drain port 20b. The drain valve 41 is located downstream of the drain filter 43 and includes, for example, a valve and a torque motor for opening and closing the valve. The drain hose 42 is connected to the drain valve 41. When the drain valve 41 is opened, the water stored in the outer tank 20 is discharged outside the machine through the drain port 20b, the drain filter 43, and the drain hose 42. Foreign matter such as lint is captured by the drain filter 43.

[0026] A water supply device 50 is located at the top of the housing 10. The water supply device 50 supplies water to the outer tank 20. The water supply device 50 also functions as an automatic detergent dispenser, automatically dispensing liquid detergent and liquid fabric softener into the outer tank 20.

[0027] The water supply device 50 includes a water supply valve unit 51 and a water injection unit 52.

[0028] The water supply valve unit 51 includes a water supply valve 110, a first water supply hose 120, and a second water supply hose 130. The water supply valve 110 has a first valve 111 and a second valve 112. The water inlet 113 of the water supply valve 110 is connected to a water tap via a connecting hose (not shown).

[0029] The inlet of the first water supply hose 120 is connected to the first valve 111, and the inlet of the second water supply hose 130 is connected to the second valve 112. When the first valve 111 is opened, water flows into the first water supply hose 120, and when the second valve 112 is opened, water flows into the second water supply hose 130.

[0030] The water injection unit 52 includes a water inlet member 140 with an open front, a liquid tank section 150 housed in the water inlet member 140 in a retractable manner, a water channel forming member 160 positioned on the upper surface of the water inlet member 140, and a pump unit 170 positioned on the rear surface of the water inlet member 140.

[0031] A water inlet 141 is formed at the bottom of the water inlet member 140. A water inlet pipe 53 extending from the water inlet 141 is connected to the outer tank 20.

[0032] The liquid tank section 150 includes a detergent tank 151 for storing liquid detergent and a fabric softener tank 152 for storing liquid fabric softener. The liquid tank section 150 is housed in the water inlet member 140 through a receiving opening 13 provided on the front of the housing 10. A lid 153 is provided on the front of the liquid tank section 150 to close the receiving opening 13.

[0033] Inside the water channel forming member 160, a first water channel is formed to which the outlet of the first water supply hose 120 is connected, and a second water channel is formed to which the outlet of the second water supply hose 130 is connected.

[0034] The pump unit 170 includes a detergent pump 171 that supplies liquid detergent from the detergent tank 151 into the first water channel, and a fabric softener pump 172 that supplies fabric softener from the fabric softener tank 152 into the first water channel (see Figure 3).

[0035] The water supplied from the first water supply hose 120 to the water channel forming member 160 flows through the first water channel and is discharged to the bottom of the water inlet member 140, and is supplied into the outer tank 20 via the water inlet 141 and the water inlet pipe 53.

[0036] When liquid detergent or liquid fabric softener is automatically dispensed into the outer tank 20, the liquid detergent or liquid fabric softener is introduced into the first water channel from the liquid tank section 150 by the pump unit 170 before the first valve 111 is opened. The liquid detergent or liquid fabric softener is mixed with the water flowing through the first water channel and supplied into the outer tank 20.

[0037] The drum-type washing machine 1 is equipped with a water level detection unit 60 for detecting the water level in the outer tub 20. The water level detection unit 60 includes an air trap 61 connected to the drain port 20b at the bottom of the outer tub 20, a water level sensor 62 positioned at the top of the outer tub 20, and a hose 63 connecting the air trap 61 and the water level sensor 62. The hose 63 is made of resin, its lower end is connected to the connection port 61a at the top of the air trap 61, it extends upward from the air trap 61, and its upper end is connected to the inlet 62a of the water level sensor 62. The water level sensor 62 is a pressure-type water level sensor that detects the water level in the outer tub 20 by detecting the air pressure in the air trap 61, and outputs a frequency signal to the control unit 201 as a detection signal corresponding to the detected air pressure, i.e., the water level.

[0038] Furthermore, due to its performance, the water level sensor 62 cannot detect the water level when the water level in the outer tank 20 is very low and the change in air pressure in the air trap 61 from a state where there is no water in the outer tank 20 is very small. Therefore, the water level sensor 62 outputs a frequency signal with the same value as when there is no water, even if the water level changes until it reaches a detectable level. In other words, the water level sensor 62 detects that the water level in the outer tank 20 is zero until it reaches a detectable level. When the outer tank 20 is filled with water up to a detectable level, the drum 23 is not yet submerged in the water.

[0039] Figure 3 is a block diagram showing the configuration of the drum-type washing machine 1.

[0040] In addition to the above-described configuration, the drum-type washing machine 1 includes a control unit 201, a storage unit 202, an operation unit 203, a display unit 204, a sound output unit 205, a door lock device 206, a motor drive unit 207, a water supply drive unit 208, a drainage drive unit 209, and a pump drive unit 210.

[0041] The control unit 203 includes a power button for turning the power on and off, a course selection button for selecting a desired washing course from multiple washing courses, and a start button for starting and pausing the washing operation. The control unit 203 outputs an input signal to the control unit 201 corresponding to the button pressed by the user.

[0042] The display unit 204 includes light-emitting elements such as LEDs and a display such as a liquid crystal panel, and, in accordance with control signals from the control unit 201, displays the selected operating course, displays the progress of the washing operation, and notifies of abnormalities. As will be described later, the display unit 204 functions as a notification unit that provides a first notification in response to a water supply abnormality and a second notification in response to a water level detection abnormality during the water supply process.

[0043] The operation unit 203 and the display unit 204 may be configured as an operation display unit such as a touch panel.

[0044] The sound output unit 205 includes a speaker, and outputs sounds such as voice and alarm sounds from the speaker.

[0045] The door lock device 206 locks the door 12 in the closed position. The door lock device 206 includes, for example, an insertion part into which a door hook provided on the rear surface of the door 12 is inserted, an engagement part that engages with the door hook inserted into the insertion part to prevent the door hook from coming out of the insertion part, and a solenoid that moves the engagement part between an engaged position and a released position.

[0046] The motor drive unit 207 drives the drive motor 30 according to a control signal from the control unit 201. The motor drive unit 207 includes a rotation sensor for detecting the rotational speed of the drive motor 30, an inverter circuit, etc., and adjusts the drive power so that the drive motor 30 rotates at the rotational speed set by the control unit 201. Furthermore, the motor drive unit 207 includes a current detection unit 207a for detecting the current flowing through the drive motor 30.

[0047] The water supply drive unit 208 drives the first valve 111 and the second valve 112 of the water supply valve 110 according to the control signal from the control unit 201. The drainage drive unit 209 drives the drainage valve 41 according to the control signal from the control unit 201. The pump drive unit 210 drives the detergent pump 171 and the fabric softener pump 172 of the pump unit 170 according to the control signal from the control unit 201.

[0048] The memory unit 202 includes EEPROM, RAM, etc. The memory unit 202 stores programs for executing various washing cycles. The memory unit 202 also stores various parameters and control flags used for executing these programs.

[0049] The control unit 201, which includes a CPU and the like, controls the display unit 204, sound output unit 205, door lock device 206, motor drive unit 207, water supply drive unit 208, drainage drive unit 209, pump drive unit 210, etc., according to a program stored in the memory unit 202, based on signals from the operation unit 203, water level sensor 62, etc.

[0050] In the drum-type washing machine 1, based on the user's operation of the control unit 203, the control unit 201 controls the washing operation for various cycles. The washing operation consists of a washing cycle, an intermediate spin-drying cycle, a rinsing cycle, and a final spin-drying cycle, performed in sequence. Depending on the cycle, the rinsing cycle and the intermediate spin-drying cycle may be performed two or more times. When the washing operation starts, the door 12 is locked by the door lock device 206.

[0051] During the washing process, water containing detergent is filled into the outer tub 20 up to a set water level for washing, which is determined according to the load of laundry in the drum 23. Then, as the drum 23 rotates repeatedly in the forward and reverse directions, the laundry immersed in the detergent-containing water tumbles. The detergent-containing water penetrates deep into the laundry, and the combined force of the detergent and the mechanical force from tumbling removes dirt attached to the surface and interior of the laundry.

[0052] In the rinsing process, the drum 23 repeatedly rotates forward and backward with water accumulated in the outer tub 20 up to a set rinsing water level corresponding to the load, causing the laundry to tumble. This causes the detergent contained in the laundry to be discharged along with the water, and the laundry is rinsed.

[0053] In the intermediate and final dewatering processes, the drive motor 30 rotates at high speed in one direction, causing the drum 23 to rotate in one direction at a speed at which the centrifugal force acting on the laundry inside the drum 23 is much greater than that of gravity. Due to the action of centrifugal force, the laundry is pressed against the inner surface of the drum 23 and dewatered. In the final dewatering process, the drum 23 rotates at a higher speed than in the intermediate dewatering process.

[0054] Before the washing process, a load detection process is performed to detect the load of laundry. The drum 23 rotates at a rotational speed that causes the laundry inside to tumble, and the current value flowing to the drive motor 30 is detected by the current detection unit 207a as the load applied to the drum 23 during rotation. The greater the load of laundry, the greater the load applied to the drum 23 and the greater the current value flowing to the drive motor 30. The control unit 201 determines the load based on the load, i.e., the magnitude of the current value. Based on the load, the amount of detergent to be added in the washing process and the amount of fabric softener to be added in the rinsing process are determined. The greater the load, the greater the amount to be added. Also, based on the load, the set water levels for the washing and rinsing processes are determined.

[0055] During the water supply process in the washing and rinsing cycles, water is supplied to the outer tank 20 through the water supply pipe 53 by the water supply device 50 until it reaches a set water level. In addition, during the water supply process in the washing cycle, the water supply device 50 automatically dispenses liquid detergent from the detergent tank 151 along with the water supply, and during the water supply process in the rinsing cycle, the water supply device 50 automatically dispenses liquid fabric softener from the fabric softener tank 152 along with the water supply. If the rinsing cycle is performed two or more times, the liquid fabric softener is dispensed during the final rinse cycle.

[0056] Figures 4 and 5 are flowcharts showing the control processes executed by the control unit 201 during the water supply process.

[0057] Referring to Figures 4 and 5, when the water supply process begins, the control unit 201 uses the water level detection unit 60 to detect the water level in the outer tank 20 before the start of water supply (S101). Normally, there is no water in the outer tank 20, so the detected water level is zero. The detected water level is stored in the storage unit 202.

[0058] Next, the control unit 201 rotates the drum 23 using the drive motor 30 at a rotational speed that causes the laundry inside the drum 23 to tumble (S102). The control unit 201 then detects the current value flowing through the drive motor 30 as the load applied to the drum 23 using the load detection unit, which is the current detection unit 207a (S103). At this time, the rotational speed of the drum 23 may be equal to or different from the rotational speed during the load detection step. The detected current value is stored in the storage unit 202 as the current value before water supply starts, i.e., as the load. Alternatively, the processes in S102 and S103 may be omitted, and the current value detected in the load detection step may be stored in the storage unit 202 as the current value before water supply starts, i.e., as the load.

[0059] Next, the control unit 201 opens the water supply valve 110, namely the first valve 111 and the second valve 112 (S104). Water supply to the outer tank 20 begins, and water from the water supply pipe 53 is discharged between the outer surface of the drum 23 and the inner surface of the outer tank 20.

[0060] During the washing cycle, detergent is automatically dispensed from the water supply device 50, and during the rinsing cycle (or the final rinse cycle if there are multiple rinses), fabric softener is automatically dispensed from the water supply device 50. Therefore, when dispensing automatically, before the water supply valve 110 is opened, liquid detergent or fabric softener is supplied into the first water channel of the water supply device 50 by the operation of the detergent pump 171 or fabric softener pump 172. Thus, when water supply begins, the detergent or fabric softener in the first water channel is washed away by the water and dispensed into the outer tub 20.

[0061] The control unit 201 monitors the water level in the outer tank 20 using the water level detection unit 60 and checks whether the water level in the outer tank 20 has reached the specified water level before the first time limit elapses from the start of water supply (S105~S107). The control unit 201 determines that the specified water level has been reached if the detected water level is equal to or greater than the specified water level.

[0062] The specified water level is the water level in the outer tank 20 that is submerged in the water, and is set lower than the set water level. The specified water level is also lower than the lower end of the inlet 11. The first time limit is set so that, when water is supplied from the water supply device 50 at a flow rate within the normal range, the water level in the outer tank 20 can reach the specified water level, but cannot reach the lower end of the inlet 11.

[0063] If the control unit 201 determines that the water level in the outer tank 20 has reached the specified water level before the first time limit elapses (S106: YES), it closes the water supply valve 110 (S116) and executes the processes S117 to S134 in Figure 5, which will be described later, in order to supply water up to the set water level.

[0064] On the other hand, if the control unit 201 determines that the first time limit has elapsed without the water level in the outer tank 20 reaching the specified water level (S106: NO → S107: YES), it considers that an abnormality has occurred in the water supply process and closes the water supply valve 110 (S108). Then, the control unit 201 executes the following processes S109 to S115 to identify the type of abnormality and issue an abnormality notification according to the type.

[0065] The control unit 201 compares the water level in the outer tank 20 before the start of water supply, as detected in S101, with the water level in the outer tank 20 after the first time limit has elapsed, as detected in S106, to determine whether the water level in the outer tank 20 has changed since before the start of water supply (S109). For example, the control unit 201 determines that there has been no change in the water level if the difference between the two water levels is smaller than a predetermined range that takes detection errors into account, that is, if the two water levels are approximately equal.

[0066] If the water level in the outer tank 20 has changed since before the start of water supply, it is assumed that some water has accumulated in the outer tank 20 due to the water supply from the water supply device 50, and that water level has been detected. Therefore, in this case, it is highly likely that the water level detection unit 60 is functioning normally, and that there is a problem with the water supply system, such as the water tap and water supply device 50, or the drainage system, such as the drainage unit 40, which is preventing water from accumulating properly in the outer tank 20, i.e., a water supply abnormality (which can also be called a water supply / drainage abnormality) has occurred.

[0067] Therefore, if the control unit 201 determines that the water level in the outer tank 20 has changed since before the start of water supply (S109: YES), it causes the display unit 204 to issue a first notification corresponding to the water supply abnormality (S110). For example, the display unit 204 displays an error code corresponding to the water supply abnormality.

[0068] When the display unit 204 issues a first notification based on the occurrence of a water supply abnormality, the water supply process is stopped and the washing operation is halted.

[0069] If the water level in the outer tank 20 has not changed since before the start of water supply, it can be assumed that a water supply abnormality has occurred, in which little or no water has been supplied by the water supply device 50 from the beginning of water supply. Furthermore, it can be assumed that although water is being supplied to the outer tank 20 normally, there is a malfunction or other abnormality in the water level detection unit 60, and the water level in the outer tank 20 is not being detected normally, i.e., a water level detection abnormality has occurred.

[0070] Therefore, if the control unit 201 determines that the water level in the outer tank 20 has not changed since before the start of water supply (S109: NO), it rotates the drum 23 in the same way as in S102 (S111), and detects the current value flowing to the drive motor 30 as the load applied to the drum 23 in the same way as in S103 (S112). Then, the control unit 201 compares the current value detected in S103 before the start of water supply with the current value detected in S112 after the first time limit has elapsed to determine whether the current value of the drive motor 30, that is, the load applied to the drum 23, has changed since before the start of water supply (S113).

[0071] If a water supply malfunction occurs, the drum 23 is not submerged in water, and the laundry inside the drum 23 is not wet. Therefore, the load applied to the rotating drum 23, i.e., the current value of the drive motor 30, will be approximately the same as before water supply started, although there may be some variation due to detection errors and the tumbling state of the laundry. On the other hand, if a water level detection malfunction occurs, in reality, there is often more water than the specified level accumulated in the outer tub 20, the drum 23 is submerged in water, and the laundry inside the drum 23 is wet and heavy. Therefore, the load applied to the rotating drum 23, i.e., the current value of the drive motor 30, will be greater than before water supply started.

[0072] For example, the control unit 201 determines that there is no change in the current value, i.e., the load, when the difference between the two detected current values ​​is smaller than a predetermined range that takes into account detection errors, that is, when the two detected current values ​​are approximately equal.

[0073] If the control unit 201 determines that the current value of the drive motor 30 has not changed since before the start of water supply (S113: NO), it causes the display unit 204 to issue a first notification corresponding to the occurrence of a water supply abnormality (S110).

[0074] On the other hand, if the control unit 201 determines that the current value of the drive motor 30 has changed since before the start of water supply (S113: YES), it causes the display unit 204 to issue a second notification corresponding to the occurrence of a water level detection abnormality (S114). For example, the display unit 204 displays an error code corresponding to the water level detection abnormality.

[0075] Furthermore, the control unit 201 releases the lock on the door 12 by the door lock device 206 (S115). This allows the door 12 to open, making it possible to remove the laundry from inside the drum 23. As described above, even if the first time limit elapses while water is being supplied at a normal flow rate, the water level in the outer tub 20 does not reach the bottom of the opening 11. Therefore, even if the door 12 is open, there is virtually no risk of water leaking from the opening 11.

[0076] While a water supply malfunction may occur not due to a failure of the water supply valve 110 or other components, but rather because the water tap is not properly opened, in this case, the malfunction can be resolved by the user properly opening the water tap, allowing the washing cycle to be restarted. In other words, in the case of a water supply malfunction, there is a good chance that the washing cycle can be restarted. On the other hand, in the case of a water level detection malfunction, there is a malfunction or other problem with the water level detection unit 60, making it difficult for the user to resolve the malfunction, and there is almost no chance that the washing cycle can be restarted. Therefore, in this embodiment, if a water supply malfunction occurs, the door 12 is not unlocked when the first notification is given, and if a water level detection malfunction occurs, the door 12 is unlocked when the second notification is given.

[0077] Based on the occurrence of a water level detection abnormality, a second notification is issued by the display unit 204, and when the door 12 is unlocked, the water supply process is stopped and the washing operation is stopped.

[0078] Now, the control unit 201 closes the water supply valve 110 based on the fact that the water level in the outer tub 20 has reached the specified water level before the first time limit has elapsed (S106: YES → S116). Next, the drive motor 30 rotates the drum 23 at a rotational speed that causes the laundry inside the drum 23 to tumble (S117). The control unit 201 then detects the current value flowing through the drive motor 30 as the load applied to the drum 23 (S118). At this time, the rotational speed of the drum 23 may be equal to or different from the rotational speed during the rotation in the load detection step and the rotation before the start of water supply in S102. The detected current value is stored in the storage unit 202 as the current value at the time of determination that the specified water level has been reached, i.e., as the load.

[0079] Next, the control unit 201 opens the water supply valve 110 (S119). This resumes the supply of water into the outer tank 20.

[0080] The control unit 201 monitors the water level in the outer tank 20 using the water level sensor 62 and checks whether the water level in the outer tank 20 has reached the set water level before the second time limit elapses after the water supply is restarted (S120~S122).

[0081] If the control unit 201 determines that the water level in the outer tub 20 has reached the set water level before the second time limit elapses (S121: YES), it closes the water supply valve 110 (S123) and ends the water supply process. The washing operation then moves on to the process in which the drum 23 rotates for washing or rinsing, following the water supply process.

[0082] On the other hand, if the control unit 201 determines that the second time limit has elapsed without the water level in the outer tank 20 reaching the set water level (S121: NO → S122: YES), it considers that an abnormality has occurred in the water supply process and closes the water supply valve 110 (S124). Then, the control unit 201 identifies the type of abnormality by executing the following processes S125 to S134 and provides an abnormality notification according to the type.

[0083] The control unit 201 compares the water level in the outer tank 20 detected in S105 when it is determined in S106 that the specified water level has been reached with the water level in the outer tank 20 detected in S121 when the second time limit has elapsed, to determine whether the water level in the outer tank 20 has changed since it was determined that the specified water level had been reached (S125). For example, the control unit 201 determines that there has been no change in the water level if the difference between the two water levels is smaller than a predetermined range that takes detection errors into account, that is, if the two water levels are approximately equal.

[0084] If the control unit 201 determines that the water level in the outer tank 20 has changed since the determination that it had reached the specified water level (S125: YES), it determines that there is a high possibility that a water supply abnormality has occurred, and therefore causes the display unit 204 to issue a first notification corresponding to the water supply abnormality (S126).

[0085] When the display unit 204 issues a first notification based on the occurrence of a water supply abnormality, the water supply process is stopped and the washing operation is halted.

[0086] If the water level in the outer tank 20 has not changed since the determination that it has reached the specified water level, it can be assumed that a water supply abnormality has occurred, for example, that the water supply valve 110 failed to open when water supply to the outer tank 20 was restarted. Furthermore, it can be assumed that a water level detection abnormality has occurred, such as that the water level detection unit 60 malfunctioned after water supply to the outer tank 20 started, and the water level sensor 62 continued to output a frequency signal indicating a water level above the specified water level. In this case, the control unit 201 will receive a frequency signal from the water level sensor 62 indicating a water level above the specified water level in S105, and will determine in S106 that the specified water level has been reached.

[0087] Therefore, if the control unit 201 determines that the water level in the outer tank 20 has not changed since the determination that it has reached the specified water level (S125: NO), it rotates the drum 23 in the same way as in S117 (S127) and detects the current value flowing to the drive motor 30 as the load applied to the drum 23 in the same way as in S118 (S128). Then, the control unit 201 compares the current value at the time of the determination that it has reached the specified water level, as detected in S118, with the current value at the time of the second time limit, as detected in S128, to determine whether the current value of the drive motor 30, i.e., the load applied to the drum 23, has changed since the determination that it has reached the specified water level (S129).

[0088] If a water supply abnormality occurs, the amount of water submerged in the drum 23 does not change from the time it is determined that the specified water level has been reached, and the amount of water contained in the laundry inside the drum 23 also does not change. Therefore, the load applied to the rotating drum 23, i.e., the current value of the drive motor 30, will be approximately the same as when it is determined that the specified water level has been reached, although there may be some variation due to detection errors and the tumbling state of the laundry. On the other hand, if a water level detection abnormality occurs, the amount of water submerged in the drum 23 increases from the time it is determined that the specified water level has been reached, and the amount of water contained in the laundry inside the drum 23 also increases, making it heavier. Therefore, the load applied to the rotating drum 23, i.e., the current value of the drive motor 30, will be greater than when it is determined that the specified water level has been reached.

[0089] For example, the control unit 201 determines that there is no change in the current value, i.e., the load, when the difference between the two detected current values ​​is smaller than a predetermined range that takes into account detection errors, that is, when the two detected current values ​​are approximately equal.

[0090] If the control unit 201 determines that the current value of the drive motor 30 has not changed since the determination that the specified water level has been reached (S129: NO), it causes the display unit 204 to issue a first notification corresponding to the occurrence of a water supply abnormality (S126).

[0091] On the other hand, if the control unit 201 determines that the current value of the drive motor 30 has changed since the determination that the specified water level has been reached (S129: YES), it causes the display unit 204 to issue a second notification corresponding to the occurrence of a water level detection abnormality (S130).

[0092] If the second time limit elapses while water is being supplied at a flow rate within the normal range, the water level in the outer tank 20 will have risen above the lower end of the inlet 11. Therefore, if the door 12 is opened in this state, water will leak out of the inlet 11.

[0093] Therefore, the control unit 201 opens the drain valve 41 for a predetermined drainage time (S131-S133). As a result, the drainage unit 40 drains water from inside the outer tank 20. The drainage time is set to allow the amount of water that could accumulate in the outer tank 20 when water is supplied at the maximum flow rate within the normal range for the second limit time to be drained down to a water level at least below the lower end of the inlet 11. The drainage time may also be set to allow all the water to be drained from inside the outer tank 20. In addition, the drain valve 41 may be kept open instead of being closed.

[0094] Subsequently, the control unit 201 releases the lock on the door 12 by the door lock device 206 (S134). Since the water level does not rise above the lower end of the input opening 11, water does not leak from the input opening 11 even when the door 12 is opened.

[0095] Based on the occurrence of a water level detection abnormality, a second notification is issued by the display unit 204, and when the door 12 is unlocked, the water supply process is stopped and the washing operation is stopped.

[0096] The drum-type washing machine 1 of this embodiment may also be equipped with a drying device for drying laundry. In this case, the drying device includes, for example, a circulation path connected to the outer tub 20. A blower fan, a cooler, and a heater are arranged within the circulation path. Air heated by the heater circulates between the outer tub 20 and the circulation path by the operation of the blower fan, drying the laundry in the drum 23. The air returning from the outer tub 20 to the circulation path is cooled and dehumidified by the cooler before being heated by the heater.

[0097] <Effects of the Embodiment> According to this embodiment, the control unit 201 rotates the drum 23 with the drive motor 30 and detects the load applied to the drum 23, then starts supplying water to the outer tank 20 with the water supply device 50. If it is determined that the first time limit has elapsed before the water level in the outer tank 20 reaches a specified water level after the start of water supply, the control unit 201 determines whether the water level in the outer tank 20 detected by the water level detection unit 60 at the end of the first time has changed from before the start of water supply. If the control unit 201 determines that the water level in the outer tank 20 has changed from before the start of water supply, it causes the display unit 204 to issue a first notification corresponding to a water supply abnormality. If the control unit 201 determines that the water level in the outer tank 20 has not changed from before the start of water supply, it rotates the drum 23 to detect the load applied to the drum 23 and determines whether the load has changed from before the start of water supply to the outer tank 20. Then, if the control unit 201 determines that the load applied to the drum 23 has not changed since before the start of water supply, it causes the display unit 204 to issue a first notification. If the control unit 201 determines that the load applied to the drum 23 has changed since before the start of water supply, it causes the display unit 204 to issue a second notification corresponding to the occurrence of a water level detection abnormality.

[0098] With this configuration, abnormalities that occur when supplying water to the outer tank 20 can be distinguished and notified to the user as either water supply abnormalities or water level detection abnormalities.

[0099] Furthermore, according to this embodiment, if the control unit 201 determines that the water level in the outer tank 20 has reached a specified water level before the first time limit has elapsed, it rotates the drum 23 with the water supply to the outer tank 20 stopped, detects the load applied to the drum 23, and then resumes the water supply to the outer tank 20. If the water level detection unit 60 does not detect that the water level in the outer tank 20 has reached a set water level even after the second time limit has elapsed since the water supply was resumed, the control unit 201 determines whether the water level in the outer tank 20 detected by the water level detection unit 60 at the end of the second time has changed since the determination that the specified water level had been reached. If the control unit 201 determines that the water level in the outer tank 20 has changed since the determination that the specified water level had been reached, it causes the display unit 204 to issue a first notification. If the control unit 201 determines that the water level in the outer tank 20 has not changed since the determination that the specified water level had been reached, it rotates the drum 23 to detect the load applied to the drum 23 and determines whether the load has changed since the determination that the specified water level had been reached. Then, if the control unit 201 determines that the load applied to the drum 23 has not changed since the determination that the specified water level has been reached, it causes the display unit 204 to issue a first notification. If the control unit 201 determines that the load applied to the drum 23 has changed since the determination that the specified water level has been reached, it causes the display unit 204 to issue a second notification.

[0100] With this configuration, it is possible to determine whether a water supply abnormality or a water level detection abnormality has occurred in two stages: the stage when water is supplied to a specified water level lower than the set water level, and the stage when water is supplied from the specified water level to the set water level, and to inform the user of which abnormality has occurred.

[0101] Furthermore, according to this embodiment, when the control unit 201 causes the display unit 204 to issue a second notification corresponding to the occurrence of a water level detection abnormality, it unlocks the door 12 using the door lock device 206, and before unlocking the door 12, it drains water from inside the outer tank 20 using the drain unit 40.

[0102] With this configuration, when a water level detection error occurs and there is little prospect of restarting the washing cycle, the user can open the door 12 and remove the laundry from inside the drum 23. Moreover, when the lock on the door 12 is released, the water level in the outer tub 20 can be made lower than the bottom edge of the loading opening 11, thus preventing water from leaking from the loading opening 11 when the door 12 is opened.

[0103] Although embodiments of the present invention have been described above, the present invention is not limited in any way by the above embodiments, and various modifications are possible to the embodiments of the present invention other than those described above.

[0104] For example, in the above embodiment, the specified water level is set to a water level lower than the set water level. However, the specified water level may be set to the same water level as the set water level. That is, the set water level may be the specified water level. In this case, in the water supply process shown in Figures 4 and 5, the processes S117 to S134 are not executed after S116, and the processes S131 to S133 are executed between the processes of S114 and S115.

[0105] Furthermore, in the above embodiment, when it is determined that a water level detection abnormality has occurred at the stage when water is supplied up to the specified water level, and a second notification is given in S114, there is virtually no risk of water leakage from the inlet 11, so drainage from the outer tank 20 does not occur before the lock on the door 12 is released in S115. However, in order to reliably prevent water leakage from the inlet 11, drainage from the outer tank 20 may occur before the lock on the door 12 is released. In this case, the same process as in S131 to S133 is performed. However, the drainage time is shortened.

[0106] Furthermore, in the above embodiment, the door 12 is unlocked when it is determined that a water level detection abnormality has occurred, but the door 12 is not unlocked when it is determined that a water supply abnormality has occurred. However, the door 12 may also be unlocked when it is determined that a water supply abnormality has occurred.

[0107] Furthermore, in the above embodiment, the door 12 is unlocked when it is determined that a water level detection abnormality has occurred, but the door 12 does not necessarily have to be unlocked.

[0108] Furthermore, in the above embodiment, the current value flowing to the drive motor 30 is detected as the load applied to the drum 23. However, other physical quantities correlated with the load, such as the time it takes for the drum 23 to rise to a predetermined rotational speed, may also be detected as the load.

[0109] Furthermore, in the above embodiment, during the water supply process shown in Figures 4 and 5, the display unit 204 provides a first notification (S110, S126) corresponding to a water supply abnormality and a second notification (S114, S130) corresponding to a water level detection abnormality. However, in addition to the display unit 204, the sound output unit 205 may provide the first and second notifications using sound such as voice.

[0110] Furthermore, in the above embodiment, the air trap 61 of the water level detection unit 60 is connected to the drain port 20b at the bottom of the outer tank 20. However, the air trap 61 may be connected to any position at the bottom of the outer tank 20, as long as the water level inside the outer tank 20 can be detected.

[0111] In addition, the embodiments of the present invention can be modified in various ways as appropriate within the scope of the technical idea set forth in the claims. [Explanation of Symbols]

[0112] 1. Drum-type washing machine 10 cabinets 11 Inlet 12 doors 20 Outer tank 23 Drums 30 Drive motor 40 Drainage section 50 Water supply equipment 60 Water level detection unit 201 Control Unit 204 Display Unit (Notification Unit) 206 Door lock device

Claims

1. An outer tank located inside the enclosure, The outer tub contains a drum that is rotatable around a horizontal axis or around a rotation axis inclined with respect to the horizontal direction, and which holds the laundry. A drive motor for rotating the drum, A water supply device that supplies water into the outer tank, A water level detection unit for detecting the water level in the outer tank, The news department and, It comprises a control unit and, The control unit, After the drive motor rotates the drum and detects the load applied to the drum, the water supply device starts supplying water to the outer tank. If it is determined that the first time limit has elapsed since the start of water supply but before the water level in the outer tank reaches a specified water level that would immerse the drum in the water, then it is determined whether the water level in the outer tank detected by the water level detection unit at the time the first time limit has elapsed has changed from before the start of water supply. If it is determined that the water level in the outer tank has changed since before the start of water supply, the notification unit will issue a first notification corresponding to a water supply abnormality in which water is not properly filling the outer tank. If it is determined that the water level in the outer tank has not changed since before the start of water supply, the drum is rotated to detect the load applied to the drum, and it is determined whether or not the load has changed since before the start of water supply to the outer tank. If it is determined that the load applied to the drum has not changed since before the start of water supply, the first notification is made by the notification unit. If it is determined that the load applied to the drum has changed since before the start of water supply, the notification unit is instructed to issue a second notification corresponding to a water level detection abnormality in which the water level in the outer tank is not detected properly by the water level detection unit. A drum-type washing machine characterized by the following features.

2. In the drum-type washing machine according to claim 1, Water is supplied to the outer tank by the water supply device until it reaches the set water level. The specified water level is set to a water level lower than the set water level. The control unit, If it is determined that the water level in the outer tank has reached the specified water level before the expiration of the first time limit, the water supply to the outer tank is stopped, and the drum is rotated to detect the load applied to the drum, after which the water supply to the outer tank is resumed. If the water level in the outer tank does not reach the set water level even after the second time limit has elapsed since the water supply was resumed, the water level detection unit determines whether the water level in the outer tank detected by the water level detection unit at the time the second time limit elapsed has changed from the time it was determined that the specified water level had been reached. If it is determined that the water level in the outer tank has changed since the determination that it reached the specified water level, the first notification is made by the notification unit. If it is determined that the water level in the outer tank has not changed since the determination that it reached the specified water level, the drum is rotated to detect the load applied to the drum, and it is determined whether or not the load has changed since the determination that it reached the specified water level. If it is determined that the load applied to the drum has not changed since the determination that the specified water level has been reached, the first notification is given to the notification unit. If it is determined that the load applied to the drum has changed since the determination that the specified water level has been reached, the second notification is made to the notification unit. A drum-type washing machine characterized by the following features.

3. In the drum-type washing machine according to claim 1 or 2, A door that can be opened and closed covers the input slot provided in the housing, A door locking device that locks the aforementioned door to prevent it from opening, The tank further comprises a drainage section for draining water from the outer tank, The control unit, When the notification unit is to perform the second notification, the door lock device is released from its lock. Before unlocking the aforementioned door, drainage is performed from the outer tank by the drainage unit. A drum-type washing machine characterized by the following features.

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