Drum-type washing machine

Abstract

To provide a drum-type washing machine enabling a set volume of water, which is previously set, to be supplied into an outer tank, even if a drum is being driven to rotate at relatively large rotational speed.SOLUTION: A drum-type washing machine comprises: an outer tank; a drum; a water level sensor to detect water level in the outer tank; storage means to store prescribed water level in a stable zone in which output corresponding to the water level in the outer tank is properly output by the water level sensor; and control means to control volume of water to be supplied into the outer tank. When supplying the water at a set water level higher than the prescribed water level into the outer tank while rotating the drum at specified rotational speed at which centrifugal force acting on laundry in the drum is equal to or higher than gravity, the control means measures required time from start of water supply until it is detected that the output of the water level sensor reaches the prescribed water level, calculates the volume of water supplied per unit hour based on the required time and the prescribed water level, and continues to supply water until lapse of water supply time calculated by dividing the set water level by the volume of water supplied per unit hour.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a drum-type washing machine installed in, for example, a coin-operated laundry facility. [Background technology]

[0002] Conventionally, drum-type washing machines (washing / drying machines) for washing laundry such as clothes include a housing, an outer tub (water tub) and drum (rotating tub) arranged within the housing, and a water supply channel and a drain channel connected to the outer tub (see, for example, Patent Document 1). Such drum-type washing machines have a piezoelectric sensor with a built-in diaphragm as a water level sensor (water level detection unit) that detects the water level in the outer tub. The water level sensor detects the water level in the outer tub by using a diaphragm to measure the water pressure that fluctuates with changes in the water level in the outer tub, and outputs an output corresponding to the water level supplied to the outer tub.

[0003] In a conventional drum-type washing machine, when water is supplied to the outer tub, the supply of water to the outer tub is started, and when the water level sensor detects that the water level in the outer tub has reached a preset water level, the supply of water to the outer tub is stopped. When water is drained from the outer tub, the drainage of the outer tub is started, and when the water level sensor detects that the water level in the outer tub has reached zero, the drainage from the outer tub is stopped. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-104227 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, for example, in a drum-type washing machine installed in a coin laundry, in addition to laundry such as clothes, futons such as mattresses may be washed. When washing a futon, if the drum is rotated at a relatively low rotation speed similar to when washing clothes, the futon will lose its shape. Therefore, in order to prevent the futon from losing its shape, it is common to wash the futon after supplying water while rotating the drum at a relatively high rotation speed that keeps the futon attached to the inner peripheral surface of the drum.

[0006] Here, with reference to Figure 7, we will explain how the output of the water level sensor changes when water is supplied into the outer tub while the drum is rotated at a relatively low rotation speed and when water is supplied into the outer tub while the drum is rotated at a relatively high rotation speed.

[0007] First, when water is supplied to the outer tub while the drum is rotating at a relatively low rotation speed, as time passes from the start of water supply and the water level in the outer tub gradually increases, the output of the water level sensor changes in proportion to the water level in the outer tub, as shown in Figure 7(a). At that time, the output of the water level sensor always indicates the water level in the outer tub correctly after water supply to the outer tub starts. In this way, at a slow rotation speed such as when washing clothes, positive pressure acts on the water level sensor regardless of the amount of water, and the water level sensor can accurately measure the water level in the outer tub.

[0008] In contrast, if water is supplied to the outer tub while the drum is rotating at a relatively high rotation speed, as time passes from the start of water supply and the water level in the outer tub gradually increases, the output of the water level sensor changes almost proportionally to the water level in the outer tub, as shown in Figure 7(b), until the water level in the outer tub reaches the critical water level. However, when the water level in the outer tub exceeds the critical water level, the water flow in the outer tub becomes intense due to the high rotation speed of the drum, and normal pressure is no longer applied to the water level sensor (negative pressure may act on the water level sensor), and the output of the water level sensor no longer indicates the water level in the outer tub.

[0009] In a drum-type washing machine, if the water level sensor is unable to properly detect the water level in the outer tub when water is being supplied to the outer tub, it will be impossible to properly supply a preset amount of water into the outer tub when the wash begins.

[0010] In this way, in drum-type washing machines that use a water level sensor to detect the water level in the outer tub, there is a problem in that the water level sensor cannot accurately detect the water level when the drum is rotating at a high rotation speed and the water pressure is unstable.

[0011] Therefore, the present invention aims to provide a drum-type washing machine having a water level sensor that is capable of properly supplying a preset amount of water into the outer tub even when the drum is rotated at a relatively high rotation speed. [Means for solving the problem]

[0012] A drum-type washing machine according to one aspect of the present invention includes a drum rotatably accommodated inside an outer tub that stores water, a water level sensor that detects the water level in the outer tub based on the water pressure acting from water supplied into the outer tub, a storage means that stores a predetermined water level in a stable region where the water level sensor appropriately outputs an output corresponding to the water level in the outer tub, and a control means that controls the amount of water supplied into the outer tub, and rotates the drum at a specified rotation speed at which the centrifugal force acting on laundry accommodated in the drum is equal to or greater than the gravity acting on the laundry. In the case where water at a set water level, which is set to a water amount higher than the predetermined water level, is supplied into the outer tub while rotating the tub, the control means measures the time required from when water supply into the outer tub starts to when it is detected that the water level in the outer tub has reached the predetermined water level based on the output from the water level sensor, calculates the amount of water supply per unit time based on the required time and the predetermined water level, and continues supplying water into the outer tub until the water supply time calculated by dividing the set water level by the amount of water supply per unit time has elapsed.

[0013] In this case, the timing when the water level in the outer tub will reach the set water level can be estimated based on the water supply speed until the water level reaches a predetermined water level in a stable region where the water level sensor appropriately outputs an output corresponding to the water level in the outer tub, and the water supply operation can be stopped. Therefore, in a drum-type washing machine having a water level sensor, even when the drum is rotated at a relatively high rotation speed, a preset amount of water can be appropriately supplied to the outer tub.

[0014] It is preferable that the control means measures the time required until it is detected that the water level in the outer tank has reached the specified water level based on the output from the water level sensor each time water is supplied into the outer tank, calculates the amount of water supplied per unit time based on the required time and the specified water level, and calculates the water supply time by dividing the set water level by the amount of water supplied per unit time.

[0015] In this case, each time water is supplied into the outer tub, the timing when the water level in the outer tub will reach the set water level is estimated, so that a preset amount of water can be reliably supplied to the outer tub.

[0016] You can select the futon washing course used when washing your futon. When the futon washing course is selected, it is preferable that the control means measures the time required until it is detected that the water level in the outer tub has reached the specified water level based on the output from the water level sensor, calculates the amount of water supply per unit time based on the required time and the specified water level, and calculates the water supply time by dividing the set water level by the amount of water supply per unit time.

[0017] In this case, the timing at which the water level in the outer tub will reach the set water level is estimated only when a futon washing course in which the drum is driven to rotate at a relatively high rotation speed is selected.

[0018] The predetermined water level is preferably set to a limit water level that is the upper limit of the water level in a stable region where the water level sensor appropriately outputs an output corresponding to the water level in the outer tank.

[0019] In this case, the timing when the water level in the outer tank will reach the set water level can be estimated with high accuracy.

[0020] It is preferable that the washing machine has a detergent dispenser for dispensing detergent into the drum, and the control means controls the detergent dispenser so that detergent is dispensed after it is detected that the water level in the outer tub has reached the predetermined water level based on the output of the water level sensor.

[0021] In this case, by adding detergent while measuring the time required for the water level in the outer tub to reach a specified level based on the output from the water level sensor, it is possible to prevent the detergent from affecting the output from the water level sensor, which would cause the required time to be measured correctly.

[0022] It is preferable that the predetermined water level is set to a different value depending on the specified rotation speed.

[0023] In this case, since the water flow in the outer tub changes when the drum rotation speed differs, a predetermined water level can be appropriately set at which the water level sensor appropriately outputs an output corresponding to the water level in the outer tub.

[0024] The laundry is preferably a futon.

[0025] In this case, when washing a futon in a drum-type washing machine, even if the drum is rotated at a relatively high rotation speed, a preset amount of water can be appropriately supplied to the outer tub.

[0026] The laundry is preferably a futon mattress.

[0027] In this case, even when the drum of a drum-type washing machine is rotating at a relatively high rotation speed that keeps the mattress attached to the inner surface of the drum, a preset amount of water can be appropriately supplied to the outer tub. Effect of the Invention

[0028] According to the drum type washing machine of the present invention, even when the drum is driven to rotate at a relatively high rotation speed, a preset amount of water can be appropriately supplied to the outer tub. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a perspective view of a drum type washing machine 1 according to an embodiment of the present invention. [Diagram 2] 2 is a side cross-sectional view showing the configuration of the drum-type washing machine 1 of FIG. [Diagram 3] FIG. 1 is a control block diagram of a drum-type washing machine 1. [Figure 4] 4 is a diagram illustrating a change in the output of the water level sensor 20 during high speed rotation. FIG. [Diagram 5] 5 is a flowchart showing the procedure of the water supply operation for the standard washing course and the mattress washing course in the drum type washing machine 1. [Figure 6] 13A and 13B are diagrams illustrating a modified example of a method for setting a predetermined water level. [Figure 7] 5A and 5B are diagrams illustrating changes in the output of the water level sensor during low-speed rotation and high-speed rotation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, a drum type washing machine 1 according to an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a perspective view of the drum type washing machine 1 according to the embodiment of the present invention. Fig. 2 is a side cross-sectional view showing the configuration of the drum type washing machine 1 of Fig. 1.

[0031] 1 and 2, the drum type washing machine 1 of this embodiment has a box-shaped housing 2, an outer tub 3 having a substantially cylindrical inner circumferential surface is disposed inside the housing 2, and a drum 4 having a substantially cylindrical inner circumferential surface for accommodating laundry is supported inside the outer tub 3 by a main shaft 5 extending in the front-rear direction. The drum 4 is rotatable about a horizontal axis.

[0032] The front surface of the housing 2 is formed with an operating section 2a for a user to operate, and a clothes insertion opening 6 that faces an opening 4a formed at the front end of the drum 4. The housing 2 is provided with a door 8 for opening and closing the clothes insertion opening 6, which is opened and closed by the door 8, and laundry can be put in and taken out of the drum 4 when the door 8 is open.

[0033] A plurality of baffles 4b are provided on the inner peripheral surface of drum 4 so as to protrude into drum 4. Baffles 4b are protrusions for lifting up laundry contained in drum 4. For example, during the washing process, when drum 4 is rotated by the driving force of drive motor 11 (described later), the laundry containing water inside drum 4 is lifted by baffles 4b and falls naturally, which is called beating washing.

[0034] A large number of water passage holes 4c are drilled into the inner surface of the drum 4. Water supplied to the outer tub 3 during washing and rinsing flows into the drum 4 through the water passage holes 4c, and water expelled from the laundry inside the drum 4 during centrifugal dehydration is splashed toward the outer tub 3 through these water passage holes 4c.

[0035] A water level sensor 20 is attached to the lower end of the back surface of the outer tub 3 via a connection pipe 20a. The water level sensor 20 is connected to the inside of the outer tub 3 and is a sensor that detects the water level (water volume) in the outer tub 3 based on the water pressure acting according to the depth of the water supplied into the outer tub 3. For example, a piezoelectric sensor with a built-in diaphragm can be used as the water level sensor 20. In this case, the water level sensor 20 detects the water level in the outer tub 3 by measuring the water pressure that varies with the change in the water level in the outer tub 3 using the diaphragm, and outputs an output corresponding to the water level supplied into the outer tub 3.

[0036] The main shaft 5 is rotatably supported by a bearing 5a attached to the rear wall of the outer tub 3, and a main pulley 10 is attached to the tip of the main shaft 5 that protrudes further rearward. A drive motor 11 is installed at the bottom of the housing 2, and a motor pulley 12 is attached to the rotating shaft of the drive motor 11. The torque of the motor pulley 12 is transmitted to the main pulley 10 via a timing belt 16. As a result, when the drive motor 11 is driven, the drum 4 rotates around the main shaft 5.

[0037] A water supply pipe 30 with a water supply valve 30a installed midway is connected to the upper part of the rear wall of the outer tub 3, and when the water supply valve 30a is opened, water supplied from the outside is supplied to the outer tub 3 via the water supply pipe 30. A drain pipe 31 with a drain valve 31a installed midway is connected to a drain outlet installed at the bottom of the outer tub 3, and when the drain valve 31a is opened, the water in the outer tub 3 is discharged outside the machine through the drain pipe 31.

[0038] Fig. 3 is a control block diagram of the drum type washing machine 1. As shown in Fig. 3, the control unit 50 of the drum type washing machine 1 is composed of, for example, a microcomputer, and includes a CPU, a ROM in which a program for controlling the operation of the drum type washing machine 1 is stored, and a RAM in which data used when executing the program is temporarily stored. The operation of the drum type washing machine 1 is controlled by the control unit 50. The control unit 50 is connected to the operation unit 2a, the water level sensor 20, the water supply valve 30a, the drain valve 31a, the drive motor 11, and the detergent dispenser 25.

[0039] In the drum type washing machine 1, the user can select between a standard washing course and a futon washing course (futon washing course) by operating the operation unit 2a of the housing 2. In the drum type washing machine 1, various operation courses can be selected by operating the operation unit 2a of the housing 2, but the following explanation will be given of the futon washing course.

[0040] The mattress cleaning course is used when washing a mattress, and the machine is operated in the following order: washing step, rinsing step, and spin-drying step. When a mattress is washed in the mattress cleaning course, the mattress is folded at its widthwise center line. Then, a folded portion is formed in the mattress along its longitudinal direction, and the width becomes approximately half of its original width. After that, the mattress is folded into a ring shape and inserted into the drum 4 so that it fits along the inner circumferential surface of the drum 4.

[0041] The control unit 50 has a memory unit 51 that stores various set values, a required time measurement unit 52, a water supply rate calculation unit 53, and a water supply time calculation unit .

[0042] The memory unit 51 stores the specified rotation speed (for standard washing) and set water level (for standard washing) of the drum 4 when the standard washing course is selected, the specified rotation speed (for washing the futon) and set water level (for washing the futon) of the drum 4 when the futon washing course is selected, and the specified water level when the futon washing course is selected, etc.

[0043] (Standard rotation speed of drum 4) Specifically, the memory unit 51 stores, for example, 43 rpm as the specified rotation speed (for standard washing) of the drum 4 when the standard washing course is selected, and stores, for example, 90 rpm as the specified rotation speed (for washing the futon) of the drum 4 when the mattress washing course is selected. That is, when the standard washing course is selected, the drum 4 is rotated at 43 rpm when the washing step and the rinsing step are performed, and when the mattress washing course is selected, the drum 4 is rotated at 90 rpm when the washing step and the rinsing step are performed. That is, when the mattress washing course is selected, water is supplied to the outer tub 3 and drained from the outer tub 3 during the washing step and the rinsing step while the drum 4 is rotated at 90 rpm.

[0044] (Set water level) Specifically, the memory unit 51 stores, for example, 130 liters as the set water level (for standard washing) when the standard washing course is selected, and stores, for example, 180 liters as the set water level (for washing the mattress) when the mattress washing course is selected. That is, when the standard washing course is selected, 130 liters of water is supplied into the outer tub 3 when the washing process and the rinsing process are performed. When the mattress washing course is selected, 180 liters of water is supplied into the outer tub 3 when the washing process and the rinsing process are performed. Note that the set water level is a water surface height (height from the bottom surface of the outer tub 3 to the water surface) that is set in advance, but in this embodiment, the set water level (set water volume) is set to the amount of water supplied into the outer tub 3 until the water surface in the outer tub 3 reaches the set water level.

[0045] Thus, in this embodiment, since the drum is driven at a relatively high rotation speed when washing bedding such as a futon compared to laundry such as clothes, the water inside the drum moves to the outer periphery of the drum by centrifugal force, and therefore the set water level (for washing the futon) in the futon washing course is set to a greater amount of water than the set water level (for standard washing) in the standard washing course.

[0046] (Prescribed water level for mattress cleaning course) In the drum type washing machine 1, the change in the output of the water level sensor 20 when water is supplied into the outer tub 3 while the drum 4 is rotating at a relatively high rotation speed of 90 rpm will be described with reference to FIG.

[0047] 4, the change in the water level in the outer tub 3 over time from the start of water supply is indicated by a thin line, and the change in the output of the water level sensor 20 at that time is indicated by a thick line. Note that the water supply rate (amount of water supplied per unit time) at which water is supplied to the outer tub 3 is constant.

[0048] As time passes from the start of water supply and the water level in the outer tub 3 gradually increases linearly, the output of the water level sensor 20 changes linearly in proportion to the water level in the outer tub 3, as shown in Fig. 4, until the water level in the outer tub 3 reaches the limit water level. In this way, the output of the water level sensor 20 changes in the same way as the water level in the outer tub 3 until the water level in the outer tub 3 reaches the limit water level, so the water level sensor 20 can properly detect the water level in the outer tub 3.

[0049] Thereafter, when the water level in the outer tub 3 exceeds the critical water level, the output of the water level sensor 20 no longer changes linearly in proportion to the water level in the outer tub 3, as shown in Fig. 4. In this way, when the water level in the outer tub 3 exceeds the critical water level, the output of the water level sensor 20 changes to be different from the water level in the outer tub 3, and the water level sensor 20 can no longer properly detect the water level in the outer tub 3.

[0050] In this embodiment, the region where the water level in the outer tub 3 is from 0 to the critical water level is referred to as the "stable region," and the region where the water level in the outer tub 3 is higher than the critical water level is referred to as the "unstable region." In other words, the "stable region" is the region where the water level sensor 20 properly outputs an output corresponding to the water level in the outer tub 3, and the "unstable region" is the region where the water level sensor 20 does not properly output an output corresponding to the water level in the outer tub 3.

[0051] Therefore, in the drum type washing machine 1, the water level sensor 20 can properly detect the water level in the outer tub 3 in the "stable region", but the water level sensor 20 cannot detect the water level in the outer tub 3 in the "unstable region".

[0052] First, a case where water is supplied at the start of a washing cycle in the standard washing course in the drum type washing machine 1 will be described.

[0053] When water is supplied at the start of a washing cycle in the standard wash course, it is necessary to supply water into the outer tub 3 so that the water level in the outer tub 3 reaches a preset water level (for standard wash). In this case, when the water level sensor 20 detects that the water level in the outer tub 3 has reached the preset water level (for standard wash), the supply of water into the outer tub 3 is stopped. When washing clothes in the standard wash course, the drum 4 rotates at a rotation speed (e.g., 43 rpm) at which the centrifugal force acting on the laundry contained in the drum 4 does not exceed the gravity acting on the laundry, and the output of the water level sensor 20 also increases approximately in proportion to the increase in the actual water level (see FIG. 7(a)), so that the water level in the outer tub 3 can be accurately detected by the water level sensor 20.

[0054] Next, a case where water is supplied at the start of a washing cycle in the mattress cleaning course in the drum type washing machine 1 will be described.

[0055] Similarly, when supplying water at the start of the washing process in the mattress cleaning course, water must be supplied to the outer tub 3 so that the water level in the outer tub 3 reaches a preset water level (for cleaning the mattress). However, in the case of the mattress cleaning course, the drum 4 rotates at a rotation speed (e.g., 90 rpm) at which the centrifugal force acting on the mattress housed in the drum 4 exceeds the gravity acting on the mattress. Therefore, a phenomenon occurs in which the output of the water level sensor 20 is initially proportional to the increase in the actual water level, but gradually reaches a plateau and becomes no longer proportional, and the water level sensor 20 is no longer able to properly detect that the water level in the outer tub 3 has reached the preset water level. The above phenomenon is believed to be caused by the fact that the water flow in the outer tub 3 becomes intense as the amount of water increases due to the high rotation speed of the drum 4, and normal pressure is no longer applied to the water level sensor 20 (negative pressure acts on the water level sensor 20). In this way, if the water level sensor 20 cannot properly detect that the water level in the outer tub 3 has reached the set water level (for cleaning the mattress), it is difficult to properly stop the supply of water to the outer tub 3.

[0056] Therefore, the inventor of the present invention discovered a method for calculating the water supply speed (amount of water supplied per unit time) into the outer tub 3 of the drum type washing machine 1 in the "stable region" immediately after water supply into the outer tub 3 is started, estimating the water supply time until the water level in the outer tub 3 reaches a set water level (for cleaning a futon) using the calculated water supply speed, and appropriately stopping the water supply into the outer tub 3 at the timing when the water level in the outer tub 3 reaches the set water level (for cleaning a futon) based on the water supply time. According to this method, even in a futon cleaning course in which the water level cannot be accurately detected by the water level sensor 20, accurate water supply can be achieved by simply reusing the existing water level detection means (water level sensor) without using a new water level detection means.

[0057] When setting the predetermined water level used to calculate the water supply speed in the mattress cleaning course, first, a "stable region" in which the water level sensor 20 appropriately outputs an output corresponding to the water level in the outer tub 3 from the start of water supply into the outer tub 3 is derived by performing an experiment in advance in the drum type washing machine 1, and the limit water level is detected from the result. The predetermined water level is set in advance to a water level in the "stable region" from 0 to the limit water level in the outer tub 3. The predetermined water level is a predetermined water surface height (height from the bottom surface of the outer tub 3 to the water surface), and in this embodiment, the amount of water supplied into the outer tub 3 until the water surface in the outer tub 3 reaches the predetermined water level is set as the predetermined water level. Note that in this embodiment, a case will be described in which the limit water level, which is the upper limit of the water level in the "stable region", is set as the predetermined water level.

[0058] The required time measurement unit 52 is a so-called timer, and measures the time required from when water supply to the outer tub 3 starts until it is detected that the water level in the outer tub 3 has reached a predetermined water level, based on the output of the water level sensor 20. While the required time measurement unit 52 is measuring the required time, the rotation speed of the drum 4 is maintained at the specified rotation speed (for cleaning a futon).

[0059] The water supply rate calculation unit 53 calculates the water supply rate (amount of water supplied per unit time) based on the required time measured by the required time measurement unit 52 and the above-mentioned predetermined water level.

[0060] In this way, every time water is supplied in the mattress cleaning course in the drum type washing machine 1, the time required for it to be detected that the water level in the outer tub 3 has reached a predetermined water level is measured based on the output of the water level sensor 20 immediately after water supply into the outer tub 3 is started, and the water supply speed is calculated, thereby making it possible to properly calculate the water supply speed for the drum type washing machine 1. That is, when water is supplied to start the washing step in the mattress cleaning course in the drum type washing machine 1, the required time is measured to calculate the water supply speed, and when water is supplied to start the rinsing step in the mattress cleaning course, the required time is measured to calculate the water supply speed.

[0061] In addition, in a plurality of drum type washing machines 1, the water supply speed (amount of water supplied per unit time) when water is supplied into the outer tub 3 is not constant for all drum type washing machines 1, and may differ for each drum type washing machine 1. For example, in a coin-operated laundry shop where a plurality of drum type washing machines 1 are installed, the water supply speed for each drum type washing machine 1 often differs between a case where water is supplied to only one drum type washing machine 1 and a case where water is supplied to multiple drum type washing machines 1 at the same time. In addition, since the actual water supply speed may differ for each coin-operated laundry shop or for each water supply facility of the coin-operated laundry shop, by measuring the water supply speed each time water is supplied, accurate water supply can be automatically performed without making adjustments for each installation site of the product.

[0062] The water supply time calculation unit 54 calculates the water supply time by dividing the set water level (for cleaning the mattress) previously set for the mattress cleaning course by the water supply rate calculated by the water supply rate calculation unit 53. That is, the water supply time calculated by the water supply time calculation unit 54 indicates the time until the water level in the outer tub 3 reaches the set water level in the specific drum type washing machine 1 for which the water supply rate has been calculated.

[0063] The water supplying operation procedure for the standard washing course and the mattress washing course in the drum type washing machine 1 will be described with reference to Fig. 5. Fig. 5 is a flow chart showing the water supplying operation procedure for the standard washing course and the mattress washing course in the drum type washing machine 1.

[0064] <Step S1> In step S1, the control unit 50 judges whether or not the mattress cleaning course has been selected. If the control unit 50 judges that the mattress cleaning course has been selected, the process proceeds to step S2. If the control unit 50 judges that the standard cleaning course has been selected, the process proceeds to step S8.

[0065] <Step S2> In step S2, the control unit 50 controls the drive motor 11 to rotate the drum 4 at a relatively high specified number of revolutions (for cleaning a futon mattress), and opens the water supply valve 30a to start supplying water to the outer tub 3. At this time, the control unit 50 closes the drain valve 31a, and the water supplied to the outer tub 3 is stored in the outer tub 3 and also stored in the drum 4 through the water passage hole 4c.

[0066] <Step S3> In step S3, the control unit 50 measures, using the required time measurement unit 52, the time required from when water supply to the outer tub 3 begins to occur until it is detected that the water level in the outer tub 3 has reached a predetermined water level based on the output of the water level sensor 20.

[0067] <Step S4> In step S4, the control unit 50 calculates the water supply rate (amount of water supplied per unit time) using the water supply rate calculation unit 53 based on the required time measured by the required time measurement unit 52 and the preset water level.

[0068] <Step S5> In step S5, the control unit 50 calculates the water supply time by dividing the set water level (for cleaning the mattress) previously set for the mattress cleaning course by the water supply rate calculated by the water supply rate calculation unit 53 using the water supply time calculation unit 54.

[0069] <Step S6> In step S6, the control unit 50 determines whether the water supply time calculated by the water supply time calculation unit 54 has elapsed. If the control unit 50 determines that the water supply time has elapsed, the process proceeds to step S7. In this way, in the mattress cleaning course, the water level sensor 20 cannot detect that the water level in the outer tub 3 has reached the set water level (for cleaning the mattress), so when the water supply time has elapsed, the water level in the outer tub 3 is deemed to have reached the set water level (for cleaning the mattress).

[0070] <Step S7> In step S7, the control unit 50 closes the water supply valve 30a to stop the supply of water to the outer tub 3, because the water level in the outer tub 3 has reached the set water level for the standard cleaning course or the mattress cleaning course.

[0071] <Step S8> In step S8, the control unit 50 controls the drive motor 11 to rotate the drum 4 at a relatively small specified number of revolutions (for standard washing), and opens the water supply valve 30a to start supplying water to the outer tub 3. At this time, the control unit 50 closes the drain valve 31a, and the water supplied to the outer tub 3 is stored in the outer tub 3 and also stored in the drum 4 through the water passage hole 4c.

[0072] <Step S9> In step S9, the control unit 50 determines whether the water level detected by the water level sensor 20 has reached the set water level (for standard cleaning). If the control unit 50 determines that the water level has reached the set water level (for standard cleaning), the process proceeds to step S7.

[0073] (Example) For example, if the amount of water to be supplied when the specified water level is reached is determined to be 40 liters through prior measurement, and the time required for the mattress cleaning course measured by the required time measurement unit 52 is 50 seconds, the water supply rate calculation unit 53 calculates the water supply rate (amount of water supplied per unit time) as follows: 40(liters) / 50(seconds)=0.8(liters / second) Here, when the target water volume (set water level) in the mattress cleaning course is 180 liters, the water supply time calculation unit 54 calculates the necessary water supply time as follows. Note that the necessary water supply time includes the required time of 50 seconds. 180(liters) / 0.8(liters / second)=225(seconds) In this case, if water supply is continued until 225 seconds have elapsed since the start of water supply, the target amount of water can be accurately supplied even if the water level sensor 20 cannot detect the water level.

[0074] As described above, the drum type washing machine 1 has the detergent dispenser 25. The detergent dispenser 25 is a device that dispenses a predetermined amount of detergent into the drum 4 (into the outer tub 3). In the drum type washing machine 1, when the standard washing course is selected, the detergent is dispensed into the drum 4 at a stage where a small amount of water is dispensed after the supply of water into the outer tub 3 is started. In contrast, when the mattress washing course is selected, the detergent is not dispensed while the required time measurement unit 52 is measuring the required time. That is, the control unit 50 controls the detergent dispenser 25 so that the detergent is dispensed after it is detected that the water level in the outer tub 3 has reached a predetermined water level based on the output of the water level sensor 20 from the time when the supply of water into the outer tub 3 is started. Therefore, when the mattress washing course is selected, the detergent is dispensed into the drum 4 at a stage where more water is supplied than when the standard washing course is selected.

[0075] As described above, the drum type washing machine 1 of this embodiment includes the drum 4 rotatably accommodated inside the outer tub 3 that stores water, the water level sensor 20 that detects the water level in the outer tub 3 based on the water pressure acting from the water supplied into the outer tub 3, a memory unit (memory means) 51 that stores a predetermined water level in a stable region where the water level sensor 20 appropriately outputs an output corresponding to the water level in the outer tub 3, and a control unit (control means) 50 that controls the amount of water supplied into the outer tub 3. The centrifugal force acting on a futon (futon mattress) accommodated in the drum 4 causes the futon (futon mattress) to move in a stable manner. In the case where water at a set water level, which is set to a water volume greater than a predetermined water level, is supplied into the outer tub 3 while rotating the drum 4 at a specified rotation speed that is greater than or equal to the gravity acting on the drum 4 (above the predetermined water level), the control unit 50 measures the time required from when water supply into the outer tub 3 begins until it is detected that the water level in the outer tub 3 has reached the predetermined water level based on the output from the water level sensor 20, calculates the amount of water supplied per unit time based on the required time and the predetermined water level, and continues supplying water into the outer tub 3 until the water supply time calculated by dividing the set water level by the amount of water supplied per unit time has elapsed.

[0076] This makes it possible to estimate the timing when the water level in the outer tub 3 will reach the set water level based on the water supply speed until the water level reaches a predetermined water level in a stable region where the water level sensor 20 properly outputs an output corresponding to the water level in the outer tub 3, and to stop the water supply operation. Therefore, in the drum type washing machine 1 having the water level sensor 20, even when the drum is rotated at a relatively high rotation speed, the preset amount of water can be properly supplied to the outer tub 3.

[0077] In the drum type washing machine 1 of this embodiment, each time water is supplied into the outer tub 3, the control unit 50 measures the time required until it is detected that the water level in the outer tub 3 has reached a predetermined water level based on the output from the water level sensor 20, calculates the amount of water supplied per unit time based on the required time and the predetermined water level, and calculates the water supply time by dividing the set water level by the amount of water supplied per unit time.

[0078] This allows the timing when the water level in the outer tub 3 will reach the set water level to be estimated each time water is supplied into the outer tub 3, thereby ensuring that a preset amount of water is supplied to the outer tub 3.

[0079] In the drum type washing machine 1 of this embodiment, it is possible to select a futon cleaning course to be used when washing a futon, and when the futon cleaning course is selected, the control unit 50 measures the time required until it is detected that the water level in the outer tub 3 has reached a predetermined water level based on the output of the water level sensor 20, calculates the amount of water supply per unit time based on the required time and the predetermined water level, and calculates the water supply time by dividing the set water level by the amount of water supply per unit time.

[0080] As a result, the timing at which the water level in the outer tub 3 will reach the set water level is estimated only when a mattress washing course in which the drum 4 is driven to rotate at a relatively high rotation speed is selected.

[0081] In the drum type washing machine 1 of this embodiment, the predetermined water level is set to a limit water level that is the upper limit of the water level in the stable region where the water level sensor 20 properly outputs an output corresponding to the water level in the outer tub 3.

[0082] This makes it possible to accurately estimate the timing when the water level in the outer tub 3 will reach the set water level.

[0083] The drum type washing machine 1 of this embodiment has a detergent dispenser 25 that dispenses detergent into the drum 4, and the control unit 50 controls the detergent dispenser 25 so that detergent is dispensed after it is detected that the water level in the outer tub 3 has reached a predetermined water level based on the output of the water level sensor 20.

[0084] This prevents the detergent from affecting the output of the water level sensor 20, causing the output to become abnormal and preventing the required time from being measured properly, by adding the detergent while measuring the time required for the water level in the outer tub 3 to reach a predetermined level based on the output from the water level sensor 20.

[0085] In the drum type washing machine 1 of this embodiment, the predetermined water level is set to a limit water level that is the upper limit of the water level in the stable region where the water level sensor 20 properly outputs an output corresponding to the water level in the outer tub 3.

[0086] This makes it possible to accurately estimate the timing when the water level in the outer tub 3 will reach the set water level.

[0087] The drum type washing machine 1 of this embodiment has a detergent dispenser 25 that dispenses detergent into the drum 4, and the control unit 50 controls the detergent dispenser 25 so that detergent is dispensed after it is detected that the water level in the outer tub 3 has reached a predetermined water level based on the output of the water level sensor 20.

[0088] This prevents the detergent from affecting the output of the water level sensor 20, causing the output to become abnormal and preventing the required time from being measured properly, by adding the detergent while measuring the time required for the water level in the outer tub 3 to reach a predetermined level based on the output from the water level sensor 20.

[0089] In the drum type washing machine 1 of this embodiment, the laundry is a futon.

[0090] As a result, when washing a futon in the drum type washing machine 1, even if the drum 4 is rotated at a relatively high rotation speed, a preset amount of water can be appropriately supplied to the outer tub 3.

[0091] In the drum type washing machine 1 of this embodiment, the laundry is a futon mattress.

[0092] This allows a preset amount of water to be properly supplied to the outer tub 3 even when the drum 4 in the drum-type washing machine 1 is rotated at a relatively high rotation speed so that the mattress remains stuck to the inner surface of the drum 4.

[0093] Although the embodiment of the present invention has been described above, the specific configuration of each part is not limited to the above-described embodiment.

[0094] For example, in the above embodiment, the set water level for the mattress cleaning course was 180 liters for both the washing and rinsing steps, but the set water level for the mattress cleaning course can be set individually for each washing or rinsing step.

[0095] In the above embodiment, when the mattress cleaning course is selected in the drum type washing machine 1, the drum 4 is rotated at a preset specified number of revolutions (for mattress cleaning), but this is not limited to the above. For example, when the specified number of revolutions (for mattress cleaning) when the mattress cleaning course is selected by the owner of the coin-operated laundry shop can be changed for the drum type washing machine 1 installed in a coin-operated laundry shop, a different value of the specified water level may be set according to the changed specified number of revolutions (for mattress cleaning). In this case, since the water flow in the outer tub 3 also changes when the number of revolutions of the drum 4 changes, the specified water level at which the water level sensor 20 appropriately outputs an output corresponding to the water level in the outer tub 3 can be appropriately set.

[0096] In the above embodiment, a case has been described in which a limit water level, which is the upper limit of the water level within the range of the "stable region", is set as the predetermined water level when the mattress cleaning course is selected in the drum type washing machine 1, but this is not limiting. The predetermined water level may be set to a water level lower than the limit water level, which is the upper limit of the water level within the range of the "stable region".

[0097] The predetermined water level may be set to a value smaller than the limit water level, which is the upper limit of the water level within the range of the "stable region". For example, as shown in Fig. 6, the median water level within the range of the "stable region" may be set as the predetermined water level. In this case, when performing calculations similar to the above-mentioned (Example), for example, if the amount of water supplied when the predetermined water level is reached is 20 liters by prior measurement, and the required time measured by the required time measurement unit 52 is 25 seconds, the water supply rate calculation unit 53 calculates the water supply rate (amount of water supplied per unit time) as follows: 20(liters) / 25(seconds)=0.8(liters / second) Here, when the target water volume (set water level) in the mattress cleaning course is 180 liters, the water supply time calculation unit 54 calculates the necessary water supply time as follows. Note that the necessary water supply time includes the required time of 25 seconds. 180(liters) / 0.8(liters / second)=225(seconds) Similarly, in this case, if water supply is continued until 225 seconds have elapsed since the start of water supply, the target amount of water can be accurately supplied even if the water level sensor 20 cannot detect the water level.

[0098] In the above embodiment, for example, a piezoelectric sensor with a built-in diaphragm is used as the water level sensor 20, but the present invention is not limited to this. The water level sensor 20 may be any sensor that detects the water level in the outer tub 3 based on the water pressure acting from the water supplied into the outer tub 3.

[0099] In the above embodiment, the drum type washing machine 1 has been described, but the present invention is not limited thereto. For example, the present invention can be applied to a drum type washing and drying machine. [Explanation of symbols]

[0100] 1. Drum type washing machine 3 Outer tank 4 Drums 20 Water level sensor 50 Control section (control means) 51 Storage unit (storage means) 52 Required time measurement section 53 Water supply speed calculation section 54 Water supply time calculation section

Claims

1. A drum rotatably accommodated inside an outer tub that stores water; a water level sensor that detects a water level in the outer tub based on a water pressure acting from water supplied into the outer tub; a storage means for storing a predetermined water level in a stable region where the water level sensor appropriately outputs an output corresponding to the water level in the outer tank; A control means for controlling the amount of water supplied into the outer tub, When the drum is rotated at a specified rotation speed at which the centrifugal force acting on the laundry contained in the drum is equal to or greater than the gravity acting on the laundry, water is supplied into the outer tub at a set water level set to a water amount greater than the predetermined water level, The control means measures the time required from when water supply into the outer tub begins to reach the specified water level based on the output of the water level sensor, calculates the amount of water supply per unit time based on the required time and the specified water level, and continues to supply water into the outer tub until the water supply time calculated by dividing the set water level by the amount of water supply per unit time has elapsed.

2. The drum-type washing machine according to claim 1, characterized in that the control means measures the time required for the water level in the outer tub to reach the specified water level based on the output of the water level sensor each time water is supplied into the outer tub, calculates the amount of water supplied per unit time based on the required time and the specified water level, and calculates the water supply time by dividing the set water level by the amount of water supplied per unit time.

3. You can select the futon washing course used when washing your futon.

2. The drum type washing machine according to claim 1, wherein, when the futon washing course is selected, the control means measures the time required until it is detected that the water level in the outer tub has reached the specified water level based on the output of the water level sensor, calculates the amount of water to be supplied per unit time based on the required time and the specified water level, and calculates the water supply time by dividing the set water level by the amount of water to be supplied per unit time.

4. The drum type washing machine according to any one of claims 1 to 3, characterized in that the specified water level is set to a limit water level which is the upper limit of the water level in a stable region where the water level sensor appropriately outputs an output corresponding to the water level in the outer tub.

5. A detergent dispenser is provided for dispensing detergent into the drum, The drum type washing machine according to any one of claims 1 to 3, characterized in that the control means controls the detergent dispensing device so that detergent is dispensed after it is detected that the water level in the outer tub has reached the predetermined water level based on the output of the water level sensor.

6. 4. The drum type washing machine according to claim 1, wherein the predetermined water level is set to a different value depending on the specified rotation speed.

7. 4. The drum type washing machine according to claim 1, wherein the laundry is a futon.

8. 4. The drum type washing machine according to claim 1, wherein the laundry is a futon mattress.

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