Washing machine

Abstract

To provide a washing machine capable of detecting air leakage abnormality in a hose for connecting an air trap and a water level sensor, and capable of giving notice of the abnormality of a water level detection part.SOLUTION: In a drum type washing machine 1, a water level detection part 60 includes: an air trap connected to a bottom part of an outer tub; a water level sensor 62 for detecting an air pressure in the air trap changing according to the water level in the outer tub, and for outputting a water level signal of the value according to the water level in the outer tub to a control part 201; and a hose connecting the air trap and the water level sensor 62. In the abnormality detection processing, the control part 201 rotates a drum, acquires the water level signal from the water level sensor 62 during the rotation of the drum, and in the case where a variation value of the water level signal acquired during the rotation of the drum with respect to the water level signal acquired from the water level sensor 62 before the rotation of the drum is smaller than a threshold value, the control part determines that abnormality has occurred in the water level detection part 60. and allows a display part 204 to perform notification giving notice about the abnormality of the water level detection part 60.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Patent Document 1 describes a washing machine that has, as its water level detection unit, an air trap installed at the bottom of the outer tub and a water level sensor that the air trap is connected to via a pressure hose, and that detects the water level in the outer tub based on the transmission frequency of the water level sensor, which changes in response to changes in pressure in the air trap.The range of transmission frequencies that is output when the water level sensor is normal is preset, and if a frequency outside this range is detected, it is determined that there is an abnormality in the water level sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 63-21095 Summary of the Invention [Problem to be solved by the invention]

[0004] In addition to a malfunction of the water level sensor, a ruptured pressure hose is also a possible cause of an abnormality in the water level detection unit. If the pressure hose is ruptured, even if pressure corresponding to the water level in the outer tank is applied to the air trap, air may leak from the pressure hose, causing the pressure to be lost and preventing it from being applied to the water level sensor. This may prevent the water level sensor from detecting the water level.

[0005] In the washing machine of Patent Document 1, even if the pressure hose breaks and air leaks, the water level sensor itself is normal, so such an abnormality cannot be detected.

[0006] The present invention has been made in consideration of such problems, and aims to provide a washing machine that can detect air leakage abnormalities in the hose connecting the air trap and the water level sensor, and can alert the user to abnormalities in the water level detection unit. [Means for solving the problem]

[0007] A washing machine according to a main aspect of the present invention includes an outer tub arranged in a housing and configured to store water, an inner tub arranged in the outer tub and configured to accommodate laundry, a water supply device that supplies water to the outer tub, a water level detection unit that detects the water level in the outer tub, and a control unit that executes an abnormality detection process including determining whether an abnormality has occurred in the water level detection unit. Here, the water level detection unit includes an air trap connected to the bottom of the outer tub, a water level sensor that detects the air pressure in the air trap that changes depending on the water level in the outer tub and outputs a water level signal of a value corresponding to the water level in the outer tub to the control unit, and a hose connecting the air trap and the water level sensor. In the abnormality detection process, the control unit rotates the inner tank and acquires the water level signal from the water level sensor while the inner tank is rotating, and if the fluctuation value of the water level signal acquired during the rotation of the inner tank relative to the water level signal acquired from the water level sensor before the inner tank rotates is smaller than a threshold value, it determines that an abnormality has occurred in the water level detection unit and causes the alarm unit to issue an alarm informing the user of the abnormality in the water level detection unit.

[0008] In the washing machine according to this aspect, in the abnormality detection process, if the hose breaks and an air leak occurs, the pressure applied to the water level sensor does not increase easily even when the inner tub is rotated, and the water level signal from the water level sensor does not fluctuate easily. Based on this, the water level detection unit can detect that an abnormality has occurred due to an air leak in the hose. As a result, the alarm unit can notify the user of the abnormality in the water level detection unit.

[0009] In the washing machine of this aspect, the control unit can be configured to execute the abnormality detection process if the water level in the outer tub does not reach a specified water level within a specified time after the water supply device starts supplying water to the outer tub.

[0010] According to this configuration, if the water level in the outer tub does not reach the specified water level before the specified time has elapsed and an abnormality in the water level detection unit is suspected, an abnormality detection process is performed, so the washing operation is less likely to take a long time.

[0011] In the above configuration, a drain unit for draining water from the outer tub may be further provided. In this case, the control unit may be configured to drain water from the outer tub using the drain unit when it determines that an abnormality has occurred in the water level detection unit.

[0012] With this configuration, if the washing operation is stopped due to an abnormality in the water level detection unit, water that has accumulated in the outer tub due to the specified time of water supply can be prevented from remaining in the outer tub.

[0013] When the above configuration is adopted, the control unit can be further configured to determine that a water supply abnormality has occurred when the fluctuation value is greater than or equal to the threshold value, and to cause the notification unit to issue an alert informing the user of the water supply abnormality.

[0014] With this configuration, it is possible to notify the user of the occurrence of a water supply abnormality even if there is no abnormality in the water level detection unit.

[0015] The washing machine according to this aspect may further include an inlet provided on the front of the housing through which laundry is put, and a door covering the inlet, wherein the inner tub is a horizontal-axis drum, and the outer tub has an opening on the front surface that is connected to the inlet via an annular door packing.

[0016] With the above configuration, the outer tub is more airtight, so when air is pushed toward the inner circumferential surface of the outer tub by the rotation of the drum, the air is less likely to escape from the outer tub and more likely to flow into the air trap, making it easier for the air pressure to increase. This makes it easier to see the difference in the fluctuation value of the water level signal from the water level sensor when there is an air leak in the hose and when there is not, making it easier for the water level detection unit to detect an abnormality such as an air leak in the hose. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a washing machine that can detect an abnormality in air leakage in the hose connecting the air trap and the water level sensor and can notify of an abnormality in the water level detection unit.

[0018] The effects and significance of the present invention will become more apparent from the following description of the embodiments, however, the following embodiment is merely an example of how the present invention can be implemented, and the present invention is not limited to the following embodiment. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a side cross-sectional view showing the configuration of a drum-type 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 detector is attached according to the embodiment. [Figure 3] FIG. 3 is a block diagram showing a configuration of a drum type washing machine according to an embodiment. [Figure 4] FIG. 4 is a flowchart showing a control process executed by the control unit in the water supply process according to the embodiment. [Figure 5] FIG. 5 is a flowchart showing an abnormality detection process included in the water supply process according to the embodiment. [Figure 6] FIG. 6 is a flowchart showing a control process executed by the control unit in the water supply step according to the first modified example. DETAILED DESCRIPTION OF THE INVENTION

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A drum-type washing machine, which is one embodiment of the washing machine of the present invention, will be described below with reference to the drawings.

[0021] Fig. 1 is a side cross-sectional view showing the configuration of a drum-type 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.

[0022] The drum type washing machine 1 has a rectangular housing 10. A circular loading opening 11 through which laundry is loaded is formed on the front of the housing 10. The loading opening 11 is covered by a door 12 that can be opened and closed.

[0023] An outer tub 20 having a substantially cylindrical shape is disposed within the housing 10. The outer tub 20 is elastically supported by a plurality of dampers 21 and springs 22. A horizontal-axis drum 23, which serves as an inner tub, is rotatably disposed within the outer tub 20. 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 an inclined axis that is inclined relative to the horizontal direction.

[0024] 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 loading port 11 of the housing 10 are connected by an annular door packing 24 made of an elastic material. The peripheral surface of the closed door 12 comes into contact with the door packing 24, and the space between the loading port 11 and the door 12 is watertight.

[0025] A large number of dewatering holes 23b are formed on the inner peripheral surface of the drum 23. In addition, three baffles 25, each having a substantially triangular prism shape, are provided on the inner peripheral surface of the drum 23 at equal intervals in the circumferential direction.

[0026] A drive motor 30 is disposed behind the outer tub 20, generating torque for rotating the drum 23. The drive motor 30 is, for example, an outer rotor DC brushless motor. During the washing and rinsing cycles, the drive motor 30 rotates the drum 23 at a rotation speed at which the centrifugal force acting on the laundry inside the drum 23 is smaller than the gravity, causing the laundry to tumble. On the other hand, during the spin cycle, the drive motor 30 rotates the drum 23 at a rotation speed at which the centrifugal force acting on the laundry inside the drum 23 is much larger than the gravity, causing the laundry to stick to the inner circumferential surface of the drum 23.

[0027] A tubular drain outlet 20b is formed at the bottom of the outer tub 20. A drain unit 40, which drains water from the outer tub 20, is connected to the drain outlet 20b. The drain unit 40 is composed 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 outlet 20b. The drain valve 41 is provided 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, water stored in the outer tub 20 is discharged outside the machine through the drain outlet 20b, the drain filter 43, and the drain hose 42. Foreign matter such as lint is captured by the drain filter 43.

[0028] A water supply device 50 is disposed in the upper part of the housing 10. The water supply device 50 supplies water into the outer tub 20. The water supply device 50 also functions as an automatic detergent dispenser, and automatically dispenses liquid detergent and liquid fabric softener into the outer tub 20.

[0029] The water supply device 50 includes a water supply valve unit 51, a water injection unit 52, and a nozzle unit 53.

[0030] 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. A water supply port 113 of the water supply valve 110 is connected to a water faucet via a connecting hose (not shown).

[0031] 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.

[0032] The water injection unit 52 includes a water injection port member 140 that opens at the front, a liquid agent tank section 150 that is accommodated in the water injection port member 140 so that it can be pulled out, a water channel forming member 160 that is arranged on the upper surface of the water injection port member 140, and a pump unit 170 that is arranged on the rear surface of the water injection port member 140.

[0033] A water inlet 141 is formed at the bottom of the water inlet member 140. A water inlet pipe 54 extending from the water inlet 141 is connected to the outer tub 20.

[0034] The liquid agent tank section 150 has a detergent tank 151 in which a liquid detergent is stored and a fabric softener tank 152 in which a liquid fabric softener is stored. The liquid agent tank section 150 is accommodated in the water inlet member 140 through an accommodation opening 13 provided on the front surface of the housing 10. A lid 153 that closes the accommodation opening 13 is provided on the front surface of the liquid agent tank section 150.

[0035] Inside the water channel forming member 160, a first water channel to which the outlet of the first water supply hose 120 is connected and a second water channel to which the outlet of the second water supply hose 130 is connected are formed.

[0036] The pump unit 170 includes a detergent pump 171 that supplies the liquid detergent in the detergent tank 151 into the first water passage, and a fabric softener pump 172 that supplies the fabric softener in the fabric softener tank 152 into the first water passage (see FIG. 3).

[0037] 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 54.

[0038] When liquid detergent or liquid fabric softener is automatically dispensed into the outer tub 20, the liquid detergent or liquid fabric softener is introduced into the first water passage from the liquid agent tank 150 by the pump unit 170 before the first valve 111 is opened. The liquid detergent or liquid fabric softener is mixed with water flowing through the first water passage and supplied into the outer tub 20.

[0039] Water supplied from the second water supply hose 130 to the water channel forming member 160 flows through the second water channel and is sent to the nozzle unit 53.

[0040] Nozzle unit 53 includes a shower nozzle 180 arranged inside the upper part of door gasket 24, and a water supply hose 181 extending from the second water channel of water channel forming member 160 and connected to shower nozzle 180.

[0041] The water outlet of shower nozzle 180 faces downward and rearward, i.e., toward the bottom of drum 23. Water flowing out from the second waterway passes through water supply hose 181 to shower nozzle 180, and is then sprayed in a shower-like manner from the outlet of shower nozzle 180 toward the inside of drum 23. This causes water to splash on the laundry inside drum 23, making it easier for the water to penetrate into the laundry.

[0042] Drum-type washing machine 1 is equipped with a water level detection unit 60 for detecting the water level in outer tub 20. Water level detection unit 60 includes an air trap 61 connected to drain outlet 20b at the bottom of outer tub 20, a water level sensor 62 located at the top of outer tub 20, and a hose 63 connecting air trap 61 and water level sensor 62. Hose 63 is made of resin, and its lower end is connected to connection port 61a at the top of air trap 61, extends upward from air trap 61, and its upper end is connected to inlet 62a of water level sensor 62. Water level sensor 62 is a pressure-type water level sensor that detects the water level in outer tub 20 by detecting the air pressure in air trap 61, and outputs a frequency signal to control unit 201 as a water level signal having a value corresponding to the detected water level.

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

[0044] In addition to the above-described configuration, the drum type washing machine 1 includes a control unit 201, a memory unit 202, an operation unit 203, a display unit 204, a sound output unit 205, a motor drive unit 206, a water supply drive unit 207, a drain drive unit 208, and a pump drive unit 209.

[0045] The operation unit 203 includes a power button for turning the power on and off, a course selection button for selecting an operation course from a plurality of operation courses related to the washing operation, and a start button for starting and pausing the washing operation. The operation unit 203 outputs an input signal to the control unit 201 according to the button operated by the user.

[0046] Display unit 204 includes a display such as a light-emitting element such as an LED or a liquid crystal panel, and displays the selected operation course, the progress of the washing operation, notifies of abnormalities, etc. in accordance with a control signal from control unit 201. Display unit 204 functions as a notification unit for notifying of abnormalities in water level detection unit 60 and water supply abnormalities, as will be described later.

[0047] The operation unit 203 and the display unit 204 may be configured as an operation display unit such as a touch panel.

[0048] The sound output unit 205 includes a speaker, and outputs sounds such as voice and alarm sounds from the speaker.

[0049] The motor drive unit 206 drives the drive motor 30 in accordance with a control signal from the control unit 201. The motor drive unit 206 includes a rotation sensor that detects the rotation speed of the drive motor 30, an inverter circuit, etc., and adjusts the drive power so that the drive motor 30 rotates at the rotation speed set by the control unit 201. Furthermore, the motor drive unit 206 includes a current sensor that detects the current flowing through the drive motor 30.

[0050] The water supply driving unit 207 drives the first valve 111 and the second valve 112 of the water supply valve 110 in accordance with a control signal from the control unit 201. The drain driving unit 208 drives the drain valve 41 in accordance with a control signal from the control unit 201. The pump driving unit 209 drives the detergent pump 171 and the fabric softener pump 172 of the pump unit 170 in accordance with a control signal from the control unit 201.

[0051] The storage unit 202 includes an EEPROM, a RAM, etc. Programs for executing various operation courses of the washing operation are stored in the storage unit 202. The storage unit 202 also stores various parameters and various control flags used in executing these programs.

[0052] The control unit 201 includes a CPU, etc., and controls the display unit 204, sound output unit 205, motor drive unit 206, water supply drive unit 207, drainage drive unit 208, pump drive unit 209, etc. based on signals from the operation unit 203, water level sensor 62, etc., in accordance with a program stored in the memory unit 202.

[0053] In the drum type washing machine 1, various operation courses are performed under the control of the control unit 201 based on the user's operation of the operation unit 203. In the washing operation, a washing step, an intermediate spin-drying step, a rinsing step, and a final spin-drying step are performed in this order. Depending on the operation course, the rinsing step and the intermediate spin-drying step may be performed two or more times.

[0054] In the washing process, detergent-containing water is filled in the outer tub 20 up to a set water level for washing, which is set according to the load of laundry in the drum 23. Then, the drum 23 is repeatedly rotated forward and backward, causing the laundry immersed in the detergent-containing water to tumble. The detergent-containing water penetrates into the laundry, and the power of the detergent and the mechanical force of the tumbling remove dirt adhering to the surface and interior of the laundry.

[0055] In the rinsing process, the outer tub 20 is filled with water up to the rinse level set according to the load, and the drum 23 rotates repeatedly in both forward and reverse directions to tumble the laundry. This causes the detergent contained in the laundry to be expelled together with the water, rinsing the laundry.

[0056] In the intermediate spin-drying step and the final spin-drying step, drive motor 30 rotates in one direction at high speed, causing drum 23 to rotate in one direction at a rotation speed at which the centrifugal force acting on the laundry inside drum 23 is much greater than gravity. The centrifugal force presses the laundry against the inner circumferential surface of drum 23, causing it to be dewatered. In the final spin-drying step, drum 23 rotates at a rotation speed higher than that in the intermediate spin-drying step.

[0057] Before the washing process, a load amount detection process is performed to detect the laundry load amount. Drum 23 rotates at a rotation speed at which the laundry inside drum 23 tumbles, for example, 40 to 50 rpm, and the load applied to drum 23 during rotation is detected from the value of the current flowing through drive motor 30. The greater the laundry load amount, the greater the load applied to drum 23 and the greater the value of the current flowing through drive motor 30. Control unit 201 determines the load amount based on the magnitude of the current value. The amount of detergent to be dispensed in the washing process and the amount of fabric softener to be dispensed in the rinsing process are determined based on the load amount. The greater the load amount, the greater the amount to be dispensed.

[0058] In the water supply process carried out in the washing process and the rinsing process, the water supply device 50 supplies water into the outer tub 20 through the water injection pipe 54 and also supplies water into the outer tub 20 through the shower nozzle 180. In addition, in the water supply process of the washing process, the water supply device 50 automatically supplies water and also dispenses liquid detergent into the detergent tank 151, and in the water supply process of the rinsing process, the water supply device 50 automatically supplies water and also dispenses liquid fabric softener into the fabric softener tank 152. If the rinsing process is carried out two or more times, the liquid fabric softener is dispensed in the final rinsing process.

[0059] Fig. 4 is a flowchart showing the control process executed by the control unit 201 in the water supply process. Fig. 5 is a flowchart showing the abnormality detection process included in the water supply process.

[0060] 4, when the water supplying process is started, control unit 201 drives detergent pump 171 in the case of the washing process, and drives fabric softener pump 172 in the case of the rinsing process (S101). Detergent pump 171 and fabric softener pump 172 operate for a supply time corresponding to the supply amount determined based on the load amount. As a result, liquid detergent or liquid fabric softener is supplied into the first water channel of water supply device 50.

[0061] In addition, when the rinsing step is performed multiple times in the washing operation, the liquid fabric softener is not dispensed in the rinsing steps other than the last rinsing step, and therefore the process of S101 is not performed.

[0062] Next, the control unit 201 opens the first valve 111 and the second valve 112 (S102). Water is supplied into the outer tub 20 from both the water supply pipe 54 and the shower nozzle 180. At this time, the detergent in the first water passage is washed away by the water and poured into the outer tub 20.

[0063] The control unit 201 periodically acquires a water level signal from the water level sensor 62 and monitors whether the water level in the outer tub 20 has reached a specified water level until a specified time has elapsed (S103, S104).

[0064] Due to its performance, the water level sensor 62 cannot detect the water level when the water level in the outer tub 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 tub 20 is very small. Therefore, even if the water level changes, the water level sensor 62 outputs a frequency signal of the same value as when there is no water until the water level reaches a detectable level. The specified water level is set to a water level slightly higher than the detectable water level. The specified time is set to a time that will allow the specified water level to be reached when water is supplied from the water supply device 50 at a flow rate within the normal range. When the water level detection unit 60 detects that the specified water level has been reached, the water level sensor 62 outputs a frequency signal corresponding to the specified water level.

[0065] If the water level in the outer tub 20 reaches the specified water level before the specified time has elapsed (S103: YES), the control unit 201 continues to supply water and then monitors whether the set water level has been reached (S105). Then, if the water level in the outer tub 20 reaches the set water level (S105: YES), the control unit 201 closes the first valve 111 and the second valve 112 (S106). Water supply from the water supply device 50 stops, and the water supply process ends.

[0066] On the other hand, if the water level in the outer tub 20 does not reach the specified water level after the specified time has elapsed, that is, if the water level sensor 62 does not output a frequency signal corresponding to the specified water level (S103: NO → S104: YES), the control unit 201 determines that an abnormality has occurred and closes the first valve 111 and the second valve 112 (S107). This causes the water supply from the water supply device 50 to stop.

[0067] If the water faucet remains closed, or if a malfunction occurs in the water supply valve 110 and the first valve 111 and the second valve 112 cannot be opened, water is not supplied from the water supply device 50, and it is determined that water has not accumulated to the specified water level in the outer tub 20, as described above. In this case, a water supply abnormality has occurred.

[0068] On the other hand, even if the water level in the outer tub 20 exceeds the specified water level, if the water level detection unit 60 detects that the hose 63 is torn due to aging or other reasons, causing air leakage from the hose 63 to the extent that the air pressure in the air trap 61 does not reach the specified water level, the water level sensor 62 will not output a frequency signal corresponding to the specified water level, and it will be determined that the water has not accumulated in the outer tub 20 to the specified water level, as described above. In this case, an abnormality has occurred in the water level detection unit 60.

[0069] Therefore, in order to grasp the content of the abnormality and take appropriate measures according to the content, the control unit 201 executes the abnormality detection process shown in FIG. 5 (S108).

[0070] 5, the control unit 201 acquires a frequency signal from the water level sensor 62 (S201). Next, the control unit 201 drives the drive motor 30 to rotate the drum 23 in one direction at a specified rotation speed (S202). Then, the control unit 201 acquires a frequency signal from the water level sensor 62 while the drum 23 is rotating (S203). Thereafter, the control unit 201 stops the drum 23 (S204).

[0071] When the drum 23 rotates, if water is present at the bottom of the outer tub 20, water is forced outward from the drum 23, i.e., toward the inner circumferential surface of the outer tub 20, and if there is no water, air is forced into the air trap 61 through the drain outlet 20b. As a result, if the hose 63 is not torn, the air pressure in the air trap 61 increases compared to before the drum 23 rotated. In the drum-type washing machine 1, an air vent hole (not shown) is provided at the top of the outer tub 20, but when the door 12 is closed, the interior of the outer tub 20 is relatively airtight. Therefore, when air is forced toward the inner circumferential surface of the outer tub 20 by the rotation of the drum 23, there is little room for the air to escape from the outer tub 20, so air easily flows into the air trap 61, and the air pressure easily increases.

[0072] The faster the drum 23 rotates, the stronger the force with which water and air are pushed outward, making it easier for the air pressure in the air trap 61 to rise. The specified rotation speed of the drum 23 in S202 is set to a rotation speed such that when air at the bottom of the outer tub 20 is pushed out and into the air trap 61, the air pressure in the air trap 61 will be at least higher than the air pressure at the specified water level, assuming no air leaks in the hose 63. This makes it easier to obtain a sufficient change in the frequency signal of the water level sensor 62. Note that, in order to increase the increase in air pressure in the air trap 61, it is desirable to set the specified rotation speed to a high rotation speed such that the laundry sticks to the inner circumferential surface of the drum 23.

[0073] The control unit 201 calculates a variation value of the frequency signal while the drum 23 is rotating with respect to the frequency signal before the drum 23 rotates (S205). Then, the control unit 201 determines whether the variation value is smaller than a threshold value (S206).

[0074] If a water supply abnormality occurs, but the hose 63 is not torn and there is no air leakage, the air pressure in the air trap 61 increases due to the air flowing in as the drum 23 rotates, and the pressure applied to the water level sensor 62 increases. As a result, the frequency signal while the drum 23 is rotating fluctuates compared to before the drum 23 rotates, and the value of this fluctuation exceeds the threshold value.

[0075] If the fluctuation value is equal to or greater than the threshold value (S206: NO), the control unit 201 determines that a water supply abnormality has occurred because the water level detection unit 60 is normal, and causes the display unit 204 to issue a notification notifying the user of the water supply abnormality (S207). For example, an error code indicating the water supply abnormality is displayed on the display unit 204.

[0076] On the other hand, if the water level detection unit 60 has an abnormality such as a rupture in the hose 63, causing air to leak from the hose 63, even if water pushed out by the rotation of the drum 23 flows into the air trap 61, the pressure will escape due to the air leak from the hose 63, making it difficult for the pressure applied to the water level sensor 62 to increase. Therefore, the frequency signal while the drum 23 is rotating will be less likely to fluctuate compared to before the drum 23 rotates, and the value of this fluctuation will be smaller than the threshold value.

[0077] If the fluctuation value is smaller than the threshold value (S206: YES), the control unit 201 determines that an abnormality has occurred in the water level detection unit 60, such as an air leak in the hose 63, and causes the display unit 204 to issue a notification notifying the user of the abnormality in the water level detection unit 60 (S208). For example, an error code indicating the abnormality in the water level detection unit 60 is displayed on the display unit 204. Then, the control unit 201 opens the drain valve 41 (S209). As a result, water that has actually accumulated above the specified water level is discharged from the outer tub 20.

[0078] In this way, when the water supply abnormality or the abnormality of the water level detection unit 60 is notified and the abnormality detection process is completed, the water supply step is stopped and the washing operation is stopped.

[0079] The drum type washing machine 1 of this embodiment may also include 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 in 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, and the laundry in the drum 23 dries. The air returning to the circulation path from the outer tub 20 is cooled and dehumidified by the cooler before being heated by the heater.

[0080] <Effects of the embodiment> According to this embodiment, the water level detection unit 60 includes an air trap 61 connected to the bottom of the outer tub 20, a water level sensor 62 that detects the air pressure in the air trap 61, which changes according to the water level in the outer tub 20, and outputs a water level signal of a value according to the water level in the outer tub 20 to the control unit 201, and a hose 63 that connects the air trap 61 and the water level sensor 62. In the abnormality detection process shown in FIG. 5, the control unit 201 rotates the drum 23 and acquires a frequency signal, which is a water level signal, from the water level sensor 62 while the drum 23 is rotating. If the variation value of the frequency signal acquired during the rotation of the drum 23 relative to the frequency signal acquired from the water level sensor 62 before the rotation of the drum 23 is smaller than a threshold value, the control unit 201 determines that an abnormality has occurred in the water level detection unit 60 and causes the display unit 204 to issue an alert informing the user of the abnormality in the water level detection unit 60.

[0081] According to this configuration, in the abnormality detection process, if the hose 63 breaks and an air leak occurs, the pressure applied to the water level sensor 62 does not easily increase even when the drum 23 is rotated, and the frequency signal from the water level sensor 62 does not easily fluctuate, so the water level detection unit 60 can detect that an abnormality has occurred, that is, an air leak in the hose 63. As a result, the abnormality in the water level detection unit 60 can be notified to the user by the display unit 204.

[0082] Furthermore, according to this embodiment, the control unit 201 executes an abnormality detection process when the water level in the outer tub 20 does not reach a specified water level within a specified time after the water supply device 50 starts supplying water to the outer tub 20.

[0083] According to this configuration, if an abnormality in the water level detection unit 60 is suspected because the water level in the outer tub 20 does not reach the specified water level before the specified time has elapsed, an abnormality detection process is performed, so the washing operation is less likely to take longer than if the abnormality detection process were performed every time before water was supplied to the outer tub 20.

[0084] Furthermore, according to this embodiment, when the control unit 201 determines that an abnormality has occurred in the water level detection unit 60, the control unit 201 causes the drain unit 40 to drain water from the outer tub 20.

[0085] According to this configuration, when the washing operation is stopped due to an abnormality in the water level detection unit 60, the water accumulated in the outer tub 20 due to the specified time of water supply can be prevented from remaining in the outer tub 20.

[0086] Furthermore, according to this embodiment, when the fluctuation value is equal to or greater than the threshold value, the control unit 201 determines that a water supply abnormality has occurred, and causes the display unit 204 to issue a notification informing the user of the water supply abnormality.

[0087] If the water level in the outer tub 20 does not reach the specified water level before the specified time has elapsed, it can be assumed that a water supply abnormality has occurred, provided that no abnormality has occurred in the water level detection unit 60.

[0088] According to this configuration, if the fluctuation value is above the threshold value and therefore there is no abnormality in the water level detection unit 60, an alarm informing the user of the occurrence of a water supply abnormality is issued by the display unit 204.

[0089] Furthermore, according to this embodiment, the outer tank 20 has an opening 20a on its front surface, and the opening 20a is configured to be connected to the inlet 11 on the front surface of the housing 10 via a ring-shaped door gasket 24.

[0090] This configuration improves the airtightness inside the outer tub 20, so that when air is pushed toward the inner circumferential surface of the outer tub 20 by the rotation of the drum 23, the air is less likely to escape from the outer tub 20 and more likely to flow into the air trap 61, making it easier for the air pressure to increase. This makes it easier to see the difference in the fluctuation value of the frequency signal from the water level sensor 62 between when there is an air leak in the hose 63 and when there is not, making it easier for the water level detection unit 60 to detect an abnormality in air leakage in the hose 63.

[0091] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications to the embodiments of the present invention are possible.

[0092] <Change example 1> FIG. 6 is a flowchart showing the control process executed by the control unit 201 in the water supply process according to the first modification.

[0093] In this modification, when the water supply process is started, the control unit 201 executes the following steps S121 to S127 as an abnormality detection process before starting to supply water into the outer tub 20.

[0094] That is, similar to the abnormality detection processing of Figure 5, the control unit 201 rotates the drum 23, acquires a frequency signal from the water level sensor 62 while the drum 23 is rotating, and calculates a fluctuation value for the frequency signal acquired from the water level sensor 62 before the drum 23 rotates (S121 to S125).

[0095] If the water level detection unit 60 has an abnormality such as a rupture in the hose 63, causing air to leak from the hose 63, even if the air pushed out by the rotation of the drum 23 flows into the air trap 61, the pressure applied to the water level sensor 62 is unlikely to increase because the pressure is released by the air leaking from the hose 63. Therefore, the frequency signal while the drum 23 is rotating is less likely to fluctuate compared to before the drum 23 rotates, and the value of this fluctuation becomes smaller than the threshold value.

[0096] If the fluctuation value is smaller than the threshold value (S126: YES), the control unit 201 determines that an abnormality has occurred in the water level detection unit 60, such as air leakage from the hose 63, and causes the display unit 204 to issue a notification informing the user of the abnormality in the water level detection unit 60 (S127). The water supply process is stopped, and the washing operation is stopped.

[0097] On the other hand, if the fluctuation value is greater than or equal to the threshold value (S126: NO), the control unit 201 determines that there is no abnormality in the water level detection unit 60, and supplies liquid detergent or liquid fabric softener into the first water passage of the water supply device 50 by operating the detergent pump 171 or the fabric softener pump 172 (S101), and then opens the first valve 111 and the second valve 112 (S102) to start supplying water into the outer tub 20 accompanied by the addition of liquid detergent or liquid fabric softener.

[0098] Thereafter, if the control unit 201 determines that the water level in the outer tub 20 has not reached the specified water level even after the specified time has elapsed (S103: NO → S104: YES), it closes the first valve 111 and the second valve 112 (S107) and stops supplying water to the outer tub 20.

[0099] At this time, since the previous abnormality detection process (S121 to S127) determined that there was no abnormality in water level detection unit 60, it can be assumed that a water supply abnormality has occurred. Therefore, control unit 201 causes display unit 204 to issue a notification notifying the user of the water supply abnormality (S128). The water supply process is stopped, and the washing operation is stopped.

[0100] According to this modified example, during the water supply process, an abnormality detection process is performed before water supply by the water supply device 50 begins, so unlike the above embodiment, when an abnormality in the water level detection unit 60 is discovered, water does not accumulate in the outer tank 20, and water is less likely to be wasted.

[0101] <Other change examples> In the above embodiment, the drain valve 41 is left open after it is opened in S209 of the abnormality detection process in Fig. 5. However, the control unit 201 may close the drain valve 41 when a predetermined drain time has elapsed since the start of drainage. The drain time is set to a time that is long enough to completely drain the water accumulated in the outer tub 20 by supplying water for a specified time.

[0102] 5 is started, in S201, the control unit 201 acquires the frequency signal before the rotation of the drum 23 from the water level sensor 62. However, the control unit 201 may use the frequency signal acquired last from the water level sensor 62 before the lapse of a specified time as the frequency signal before the rotation of the drum 23, and may not perform the process of S101.

[0103] Furthermore, in the above embodiment, the air trap 61 of the water level detection unit 60 is connected to the drain outlet 20b at the bottom of the outer tub 20. However, as long as the water level in the outer tub 20 can be detected, the air trap 61 may be connected to any position at the bottom of the outer tub 20. Note that, as in the case where the air trap 61 is connected to the drain outlet 20b, if the air trap 61 is connected to the circumferential surface side of the outer tub 20 rather than the rear end face side, air and water pushed toward the inner circumferential surface side of the outer tub 20 by the rotation of the drum 23 will be more likely to flow into the air trap 61.

[0104] Furthermore, in the above embodiment, abnormalities in the water level detection unit 60 and water supply abnormalities are reported by the display unit 204. However, abnormalities in the water level detection unit 60 and water supply abnormalities may be reported by a sound such as a voice from the sound output unit 205 in addition to the display unit 204.

[0105] Furthermore, in the above embodiment, the water supply device 50 is configured to function as an automatic detergent dispenser. However, the automatic detergent dispenser may be provided separately from the water supply device 50. In this case, the automatic detergent dispenser may be configured to directly dispense liquid detergent and liquid fabric softener from the detergent tank and fabric softener tank into the outer tub 20.

[0106] Furthermore, drum type washing machine 1 may be configured so that water supply device 50 does not have the function of an automatic detergent dispenser, i.e., no automatic detergent dispenser is provided. In this case, water supply device 50 may be provided with a detergent case that stores a single dose of detergent such as powder detergent, and when first valve 111 is opened, water that has flowed through the first water channel may be discharged to the bottom of water inlet member 140 via the detergent case.

[0107] Furthermore, in the above embodiment, a drum-type washing machine 1 is shown. However, the present invention can also be applied to washing machines other than the drum-type washing machine 1, for example, a fully automatic washing machine having a vertical-axis washing and spin-drying tub as an inner tub inside an outer tub. The fully automatic washing machine may also be a fully automatic washer-dryer with a drying function. In this case, it is desirable that the opening on the top surface of the outer tub be covered with an openable lid to improve the sealing of the outer tub.

[0108] In addition, the embodiments of the present invention can be modified in various ways as appropriate within the scope of the technical ideas set forth in the claims. [Explanation of symbols]

[0109] 1. Drum washing machine 10. Cabinet 11 Inlet 12 doors 20 Outer tank 20a opening 23 Drum (inner tank) 24 Door gasket 40 Drainage section 50 Water supply equipment 60 Water level detection unit 61 Air Trap 62 Water level sensor 63 Hose 201 Control Unit 204 Display unit (notification unit)

Claims

1. an outer tank disposed within the housing and configured to store water; an inner tub disposed in the outer tub and configured to accommodate laundry; a water supply device that supplies water into the outer tank; a water level detection unit that detects the water level in the outer tank; a control unit that executes an abnormality detection process including determining whether an abnormality has occurred in the water level detection unit, The water level detection unit an air trap connected to the bottom of the outer tank; a water level sensor that detects the air pressure in the air trap, which changes depending on the water level in the outer tub, and outputs a water level signal of a value corresponding to the water level in the outer tub to the control unit; a hose connecting the air trap and the water level sensor, In the abnormality detection process, the control unit rotating the inner tub and acquiring the water level signal from the water level sensor while the inner tub is rotating; When a fluctuation value of the water level signal acquired during the rotation of the inner tub relative to the water level signal acquired from the water level sensor before the rotation of the inner tub is smaller than a threshold value, it is determined that an abnormality has occurred in the water level detection unit, and an alarm unit is caused to issue an alarm notifying the user of the abnormality in the water level detection unit. A washing machine characterized by:

2. The washing machine according to claim 1, the control unit executes the abnormality detection process when the water level in the outer tub does not reach a specified water level within a specified time period after the water supply device starts supplying water to the outer tub. A washing machine characterized by:

3. The washing machine according to claim 2, Further provided is a drainage unit for draining water from the outer tank, When the control unit determines that an abnormality has occurred in the water level detection unit, the control unit causes the drain unit to drain water from the outer tank. A washing machine characterized by:

4. The washing machine according to claim 2 or 3, The control unit determines that a water supply abnormality has occurred when the fluctuation value is equal to or greater than the threshold value, and causes the notification unit to issue a notification of the water supply abnormality. A washing machine characterized by:

5. The washing machine according to claim 1, an inlet provided on a front surface of the housing, through which laundry is put; a door covering the insertion port, The inner tank is a horizontal drum, The outer tub has an opening on the front surface, and the opening is connected to the inlet via an annular door packing. A washing machine characterized by:

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