JP7807340B2 - washing machine - Google Patents

Description

The present invention relates to a washing machine.

In washing machines, dirt can accumulate on the inner and outer tubs, so a tub cleaning process may be performed during the wash cycle or separately from the wash cycle. For example, Patent Document 1 discloses a washing machine that, during the tub cleaning process performed during the wash cycle, rotates the inner tub at a speed higher than that during the wash cycle but lower than that during the spin cycle, thereby stirring up water that has accumulated in the outer tub (paragraph 0087, etc.).

JP 2013-39211 A

However, with conventional tub cleaning processes such as the technology described in Patent Document 1, even if the tub can be cleaned by stirring up the water accumulated in the outer tub, it is difficult for the filter in the drainage path to capture the fine lint that has come off the tub. As a result, when draining the water after cleaning the tub, the lint may pass through the filter in the drainage path and be discharged outside the machine, potentially clogging the drain trap. Furthermore, the lint that has come off may remain at the bottom of the outer tub even after draining, and may re-adhere to clothes during the next wash cycle, etc.

The object of the present invention is to provide a washing machine that prevents lint from being discharged outside the machine or from re-adhering to clothes when draining after tub cleaning.

To solve the above-mentioned problems, the present invention provides a washing machine comprising a housing, an outer tub supported within the housing for storing water, an inner tub enclosed within the outer tub for storing clothes, a circulation pump for circulating water within the outer tub, a water channel filter for collecting lint contained in the water circulated by the circulation pump, a drain valve for draining water from the outer tub, and a control device for controlling the inner tub, the circulation pump, and the drain valve. The circulation pump sprays water into the inner tub from above the outer tub when rotated forward, and directs water into an inlet formed in the bottom of the outer tub when rotated reversely. The control device executes a tub cleaning process in which the drain valve is closed to rotate the inner tub while water is stored in the outer tub. The tub cleaning process includes a first cleaning process in which the inner tub rotates at a first rotational speed while the circulation pump rotates reversely, and a second cleaning process in which the inner tub rotates at a second rotational speed higher than the first rotational speed while the circulation pump rotates reversely.

This invention makes it possible to provide a washing machine that prevents lint from being discharged outside the machine or from re-adhering to clothes when draining water after tub cleaning.

FIG. 2 is a perspective view of the drum-type washer-dryer seen from diagonally above the front. Cross-sectional view of the drum type washer-dryer seen from the right. FIG. 10 is a front view of the outer tank and the air path filter when the housing and inner tank are not shown. FIG. 2 is a perspective view of the drum type washer-dryer as viewed obliquely from the front, with the housing not shown. FIG. 5 is an enlarged view of the area surrounded by the dotted line in FIG. 4 . 6 is a cross-sectional view taken along a cross section in the front-rear direction including line AA in FIG. 5. FIG. 2 is a vertical cross-sectional view showing a part of the structure of the bellows cleaning device. FIG. 2 is a perspective view of the drum type washer-dryer as seen obliquely from the front and above, with the housing and outer tub cover not shown. FIG. 9 is an enlarged view of the area surrounded by the dotted line in FIG. 8 . 6 is a flowchart showing the overall operation performed by the control device of the drum type washer-dryer when the standard course of the washing and drying operation is selected. 6 is a flowchart showing the overall operation performed by the control device of the drum type washer-dryer when a tub cleaning course is selected. 10 is a time chart showing the changes in the rotation speed of the inner tub and the changes in the operation of the circulation pump and drain valve during the tub cleaning course. FIG. 10 is a diagram showing the water level of the circulating shower when the circulating pump is stopped in the comparative example. FIG. 10 is a diagram showing the water level of the circulating shower when the circulating pump is stopped in the case of Example 2.

Embodiments of the present invention will be described below with reference to the drawings. Note that the washing machine described below will be a drum-type washer-dryer in which the rotation axis of the inner tub is approximately horizontal.

<Configuration of a drum type washer-dryer>
First, the configuration of a drum type washer-dryer 1 (hereinafter, sometimes simply referred to as a washing machine) according to this embodiment will be described with reference to Figures 1 and 2. Figure 1 is a perspective view of the drum type washer-dryer as seen obliquely from above the front, and Figure 2 is a cross-sectional view of the drum type washer-dryer as seen from the right.

The drum type washer-dryer 1 according to this embodiment includes a housing 2, a door 2a, an outer tub 3, an inner tub 4 (washing and spin-drying tub, rotating drum), an air blower 5 (air blower 5a, hot air heater 5b, hot air outlet 5c, circulation air duct 5d, air duct hose 5e, sub-air duct filter 5f), a drainage channel 6 (internal drainage channel 6a, water channel filter 6b, drain valve 6c, drain hose 6d), an air duct filter 7, a lint discharge water channel 8, a circulation pump 9, and a detergent dissolving water channel 10. Although not shown in FIG. 2 , the drum type washer-dryer 1 according to this embodiment also includes a circulation water channel 11, a fluid balancer 12, a bellows cleaning mechanism 13, a hot water heater 14, a water level sensor, a water supply unit, and a control device.

As shown in FIG. 1, the housing 2 is a box-shaped member that forms the outer shell of the drum-type washer-dryer 1, and includes a front cover 2b, a pair of left and right side panels 2c, a rear cover 2d, a top cover 2e, and a base 2f. The top cover 2e is provided with a detergent inlet and an operation panel, and the front cover 2b has a clothing inlet through which clothes (laundry) are inserted. The door 2a covers the clothing inlet and can be opened and closed via a hinge 2g so that the user can put clothes in and take them out.

As shown in Figure 2, the outer tub 3 is supported by the housing 2 and can store water inside. A ring-shaped outer tub cover 3a is provided at the front opening of the outer tub 3, and an opening for putting clothes in and taking them out is formed near the center of the outer tub cover 3a. The opening of this outer tub cover 3a and the clothes insertion opening in the front cover 2b of the housing 2 are connected via rubber bellows 15 (see Figure 7), ensuring watertightness between the door 2a and the outer tub 3 when closed. In addition, a drain outlet 3b is formed at the bottom of the bottom surface of the outer tub 3.

The inner tub 4 is contained within the outer tub 3 and rotates around the rotation axis 4a at low or high speed with clothes stored inside during each of the washing, rinsing, spin-drying, and drying processes. Note that during each process of the tub cleaning course described below, the inner tub 4 rotates without clothes stored inside. The peripheral and bottom walls of the inner tub 4 are formed with numerous through-holes 4b (not shown in Figure 2) for water and ventilation. The inner tub 4 also has an opening on its front side, and is supported so that this opening faces the door 2a when closed. Note that the rotation axis 4a of the inner tub 4 may be parallel to the horizontal plane, or may be inclined so that the opening is higher than the bottom (rear) surface.

During the drying process, the air blower 5 generates circulating air (shown by the dashed arrows in Figure 2) to dry the clothes. The air blown out from the air blower 5a is heated by the downstream hot air heater 5b and then supplied to the inner tub 4 through the hot air outlet 5c. The hot air supplied to the inner tub 4 heats the damp clothes stored in the inner tub 4, removing moisture from them, then flows through the through-holes 4b in the inner tub 4 into the gap between the inner tub 4 and the outer tub 3, passes through the air path filter 7, and reaches the circulation air path 5d connecting the outer tub 3 and the air blower 5a. Because the air flowing into the circulation air path 5d has become humid due to removing moisture from the clothes, cooling water (shown by the solid arrows in Figure 2) is supplied from the top of the circulation air path 5d to cool the high-humidity air, condensing the water vapor and dehumidifying the air. The dry air after dehumidification then passes through the air duct hose 5e and the sub-air duct filter 5f (exhaust-side air duct filter) and returns to the blower 5a. In this way, the blower 5 supplies high-temperature dry air to the damp clothes in the inner tub 4, accelerating the drying of the clothes.

The drain channel 6 is a path for draining water from the outer tub 3 and consists of an internal drain channel 6a that communicates with the drain outlet 3b on the bottom of the outer tub 3, a water channel filter 6b that collects lint in the wastewater flowing through the internal drain channel 6a, a drain valve 6c that is closed mainly during the washing and rinsing cycles and open mainly during the spin-drying and drying cycles, and a drain hose 6d through which the wastewater passes when the drain valve 6c is open. The lint collected by the water channel filter 6b is cleaned by the user as needed.

The air duct filter 7 and the sub-air duct filter 5f (exhaust-side air duct filter) are mesh filters for capturing lint contained in the circulating air, and the air duct filter 7 is disposed between the lower (upstream) side of the circulating air duct 5d and the rear surface of the outer tub 3, while the sub-air duct filter 5f (exhaust-side air duct filter) is disposed between the air duct hose 5e and the blower 5a (i.e., on the exhaust side of the circulating air duct 5d). Details regarding the collection and discharge of lint by the air duct filter 7 will be described later.
The lint discharge channel 8 connects the lower part of the circulating air channel 5d to the internal drain channel 6a.

The circulation pump 9 circulates water within the outer tub 3. Although not shown, it is composed of a motor, impeller, casing, etc. The casing has one intake port and two outlet ports. The intake port is connected downstream of the water channel filter 6b, the first outlet port is connected to the circulation water channel 11, and the second outlet port is connected to the detergent dissolving water channel 10.

The circulation water channel 11 (see Figures 4 and 5) is a water channel that guides wash water or rinse water from the first discharge port of the circulation pump 9 to a spray nozzle (not shown) formed on the outer peripheral surface of the upper front of the outer tub cover 3a. The spray nozzle is slit-shaped so that the water sprayed into the inner tub 4 spreads in a thin film.

The detergent dissolving water channel 10 (see Figure 5) is a water channel that guides wash water or rinse water from the second discharge port of the circulation pump 9 to the inlet 3c formed in front of the recessed portion 3d provided in the bottom of the outer tub 3.

The fluid balancer (see Figure 7) is a component for suppressing eccentricity due to uneven clothing positioning, etc. It is installed near the edge of the opening of the inner tub 4 and rotates integrally with the inner tub 4. The hot water heater 14 (see Figure 9) heats the wash water accumulated at the bottom of the outer tub 3 and is installed in the recess 3d of the outer tub 3. The water level sensor (not shown) detects the water level by measuring the pressure of the water accumulated in the outer tub 3. The water supply unit (not shown) includes a detergent water supply solenoid valve, a softener water supply solenoid valve, a cooling water supply solenoid valve, and a shower water supply solenoid valve. When the shower water supply solenoid valve opens, the water supply branches into three branches: shower water, which is sprayed into the inner tub 4; bellows water, which washes away lint adhering to the inner surface of the bellows (see Figure 7); and duct cleaning, which washes away lint adhering to the sub-air duct filter 5f and the circulation air duct 5d. The control device (not shown) controls the opening and closing of the solenoid valves and drain valve 6c of the water supply unit, the rotation of the motors that drive the inner tub 4 and circulation pump 9, and the operation of the air blower 5 and hot water heater 14, etc.

<Collection and discharge of lint by air duct filter>
3 is a front view of the outer tub and air duct filter when the housing and inner tub are not shown. In the washing machine of this embodiment, the blower 5a is located above the right side of the outer tub 3, so the circulation air duct 5d from the outer tub 3 to the blower 5a is located below the blower 5a and behind the outer tub 3 to connect them in the shortest distance. In addition, in the washing machine of this embodiment, in order to reduce the ventilation resistance from the outer tub 3 to the blower 5a and increase the volume of circulating air, a large, vertically elongated air intake 3e is provided on the back of the outer tub 3, and this air intake 3e is covered with a wide-area air duct filter 7.

In a washing machine, the mechanical force of clothes rubbing against each other in the inner tub 4 during the washing and rinsing cycles, and the mechanical force of the air supplied to the inner tub 4 during the drying cycle, cause clothing fibers to peel off and produce lint. The lint produced is heavy and wet at the beginning of the drying cycle, so it does not float, but as the drying process progresses it becomes lighter and begins to float. Any lint that floats up and is larger than the mesh of the air duct filter 7 is captured by the air duct filter 7 and discharged into the internal drainage channel 6a during the subsequent washing and rinsing cycles, or when the tub cleaning course described below is performed.

On the other hand, lint that floats during the drying process and is smaller than the mesh size of the air duct filter 7 passes through the air duct filter 7 and enters the circulating air duct 5d. Furthermore, it is thought that this could make it easier for the floating lint to be sucked into the blower 5a via the open section 9, or for the lint to accumulate on the heater 5b. Therefore, the above problem can be alleviated by providing a sub-air duct filter 10 between the air duct hose 5e and the blower 5a to capture lint that moves with the drying air.

Fine lint particles that enter the circulation air duct 5d absorb the cooling water supplied to the duct for dehumidification during the drying process, or the water supplied to the water tub during the washing or rinsing process, and combine with surrounding lint to form lint clumps that accumulate on the backside of the filter. However, because the lint clumps are small enough in their initial stages, they are discharged through the lint discharge channel 8 to the internal drain channel 6a along with the cooling water during the drying process, or along with the drainage from the outer tub 3 after the washing or rinsing process. At this time, the lint discharge channel duct-side connector 8a is located lower than the maximum height reached by the water flow caused by the spooling during the standard tub cleaning process described below and the third tub cleaning process in the tub cleaning course described below. Furthermore, it is desirable for the lint discharge channel duct-side connector 8a to be located lower than the maximum height reached by the water flow caused by the spooling during the second tub cleaning process in the tub cleaning course described below. This allows for more reliable lint removal, not only by the cooling water but also by the water used to clean the tank.

The diameter of the lint discharge channel 8 may be on the order of a few millimeters, but it is preferable to design the lint discharge channel 8 to have a diameter of approximately 6 to 10 mm so that even lint clumps that have grown to a certain extent can be discharged. Furthermore, it is preferable to connect the lint discharge channel drainage channel side connector 8b provided at the lower end of the lint discharge channel 8 to the upstream side of the channel filter 6b so that the lint discharged via the lint discharge channel 8 can be collected by the channel filter 6b. However, it is also possible to connect the lint discharge channel drainage channel side connector 8b to the downstream side of the channel filter 6b so that the lint clumps can be directly discharged into a sewer or the like.

<Rotation direction of the circulation pump and the generated water flow>
Figure 4 is a perspective view of the drum-type washer-dryer as viewed diagonally from the front, with the housing not shown, Figure 5 is an enlarged view of the area surrounded by the dotted line in Figure 4, and Figure 6 is a cross-sectional view taken along a cross section in the front-to-back direction including line A-A in Figure 5.

When the motor of the circulation pump 9 rotates forward, the wash water or rinse water accumulated at the bottom of the outer tub 3 is guided to the water channel filter 6b via the drain outlet 3b and internal drain channel 6a. After lint has been removed by the water channel filter 6b, the water flows into the casing through the intake port, where it becomes a swirling flow due to the centrifugal force of the impeller and is discharged from the first outlet. The water discharged from the first outlet is guided to the sprinkler nozzle via the circulation water channel 11, from which it is sprayed as a circulating shower into the inner tub 4. The sprayed water then circulates again to the drain outlet 3b of the outer tub 3 via the through-hole 4b in the inner tub 4. The water flow generated when the motor of the circulation pump 9 rotates forward is indicated by the black arrows in Figures 4 and 5.

When the motor of the circulation pump 9 rotates in reverse, the wash water or rinse water accumulating at the bottom of the outer tub 3 is guided to the water channel filter 6b via the drain outlet 3b and internal drain channel 6a. The water from which lint has been removed by the water channel filter 6b flows into the casing through the intake port, where it becomes a swirling flow due to the centrifugal force of the impeller and is discharged from the second outlet. The water discharged from the second outlet is guided through the detergent dissolving water channel 10 to the inlet 3c at the front of the bottom of the outer tub 3, then flows rearward and circulates again to the drain outlet 3b of the outer tub 3. The water flow generated when the motor of the circulation pump 9 rotates in reverse is indicated by the white arrows in Figures 4-6.

<Structure of Bellows Cleaning Device>
FIG. 7 is a longitudinal cross-sectional view showing a portion of the bellows cleaning mechanism. The bellows cleaning mechanism 13 is composed of a shower water supply solenoid valve (not shown), a bellows cleaning water channel 13a, and a bellows cleaning nozzle 13b. The bellows cleaning water channel 13a connects the shower water supply solenoid valve and the bellows cleaning nozzle 13b and extends radially inward along the inner surface of the outer tub cover 3a, facing the fluid balancer. The bellows cleaning nozzle 13b ejects tap water from the front side of the outer tub cover 3a toward the upper inner surface of the bellows 15, washing away lint adhering to the bellows 15. The washed-out lint, together with the tap water, is discharged into the internal drainage channel 6a via the drain outlet 3b of the outer tub 3 and collected by the water channel filter 6b.

<Hot water heater structure>
FIG. 8 is a perspective view of the drum-type washer-dryer as viewed obliquely from the front and above, with the housing and outer-tub cover omitted, and FIG. 9 is an enlarged view of the area surrounded by the dotted line in FIG. 8 . As described above, the hot water heater 14 heats the wash water accumulated at the bottom of the outer tub 3 and is provided in the recessed portion 3d of the outer tub 3. Lint that detaches from clothes during the washing and rinsing cycles may accumulate around the hot water heater 14. However, when the motor of the circulation pump 9 rotates in reverse while water is accumulated at the bottom of the outer tub 3, a water flow, as shown by the arrows in FIG. 9 , is generated in the recessed portion 3d of the outer tub 3. This water flow discharges lint adhering to the periphery of the hot water heater 14 into the internal drainage channel 6a via the drain outlet 3b of the outer tub 3 and is collected by the water channel filter 6b.

<Operation of the washer/dryer on the standard course>
FIG. 10 is a flowchart showing the overall operation performed by the control device of a drum-type washer-dryer when the standard wash/dry cycle is selected. When the standard cycle is selected and the start button on the operation panel is pressed, the control device sequentially executes a wash cycle (step S1), a rinse cycle (step S2), a standard tub cleaning cycle (step S3), a spin cycle (step S4), and a drying cycle (step S5), as shown in FIG. 10 . Each cycle will be described in detail below. Hereinafter, rotating the motor driving the inner tub 4 forward (reverse) may be simply referred to as "rotating the inner tub 4 forward (reverse)," and rotating the motor of the circulation pump 9 forward (reverse) may be simply referred to as "rotating the circulation pump 9 forward (reverse). Furthermore, the rotation speed of the motor of the inner tub 4 may be simply referred to as the rotation speed of the inner tub 4, and the rotation speed of the motor of the circulation pump 9 may be simply referred to as the rotation speed of the circulation pump 9.

<Washing process>
First, the control device calculates the amount of laundry before water is dispensed based on the rotation speed and current value of the motor (not shown) when rotating the inner tub 4. For example, if the current flowing through the motor is large, the load required to rotate the inner tub 4 is large, and the amount of laundry can be considered to be large.

Next, the control device opens the detergent water supply solenoid valve to supply tap water to the detergent dispenser. The tap water supplied to the detergent dispenser is then supplied to the outer tub 3 via a hose along with the detergent. Furthermore, the control device leaves the detergent water supply solenoid valve open and rotates the inner tub 4 while rotating the circulation pump 9 in reverse, thereby generating a water flow as shown by the white arrows in Figures 4-6. In the case of powder detergent, this water flow dissolves the detergent, producing a highly concentrated detergent solution. In the case of liquid detergent, the detergent dissolving operation, which reverses the rotation of the circulation pump 9, may be omitted. The rotation speed of the circulation pump 9 when dissolving the detergent is, for example, 1500 rpm.

The control device then rotates the circulation pump 9 forward while repeatedly rotating the inner tub 4 forward and backward, thereby performing a pre-wash by spraying a highly concentrated detergent solution from the spray nozzle into the inner tub 4, as shown by the black arrows in Figures 4 and 5. The rotational speed of the circulation pump 9 when spraying water from the spray nozzle is, for example, 2500 rpm.

Next, the control device opens the detergent water supply solenoid valve to supply water based on the detection value of the water level sensor until the specified water level is reached. The control device then rotates the circulation pump 9 forward while repeatedly rotating the inner tub 4 forward and backward to perform the main wash. During the main wash, the hot water heater 14 is turned on to heat the water at the bottom of the outer tub.

<Rinsing process>
The rinsing step basically includes a first rinse and a second rinse (final rinse).

During the first rinse, the control device first opens the drain valve 6c to drain the wash water used in the washing process. After draining is complete, the control device rotates (reversely) the inner tub 4 at high speed (e.g., 1250 rpm) to spin out the wash water contained in the clothes.

Next, the control device closes the drain valve 6c and opens the shower water supply solenoid valve to supply tap water to the outer tub 3. At this time, the control device rotates the inner tub 4 at a low speed while driving the circulation pump 9 in the forward direction, thereby rinsing the inner tub 4 by spraying rinsing water from the spray nozzles into the inner tub 4, as shown by the black arrows in Figures 4 and 5.

The control device first stops the inner tub 4 and circulation pump 9 and opens the drain valve 6c to drain the rinse water from the outer tub 3. After draining is complete, the control device rotates the inner tub 4 at high speed to dehydrate the rinse water contained in the clothes. This completes the first rinse.

During the second rinse, the control device closes the drain valve 6c and opens the softener water supply solenoid valve to supply tap water to the outer tub 3. Next, it closes the softener water supply solenoid valve and opens the detergent water supply solenoid valve and shower water supply solenoid valve to supply tap water to the outer tub 3. During this process, the control device rotates the inner tub 4 at a low speed and drives the circulation pump 9 in the forward direction, spraying rinse water containing softener (finishing agent) into the inner tub 4 from the spray nozzles, allowing the softener to soak into the clothes. Furthermore, when the shower water supply solenoid valve opens, as described above, tap water reaches the bellows wash nozzle 13b via the bellows wash water passage 13a and is sprayed toward the upper inner surface of the bellows 15, washing away any lint adhering to the bellows 15. This washing away includes lint that adhered to the bellows 15 during the drying process of the previous operation.

<Standard tank cleaning process>
In the standard tub cleaning process, the control device first opens the drain valve 6c to drain the rinse water used in the rinsing process. After draining is complete, the control device rotates (reversely rotates) the inner tub 4 at high speed (e.g., 900 rpm) for a predetermined time to dehydrate the rinse water contained in the clothes.

The control device then reduces the rotation speed of the inner tub 4, and when the inner tub 4 reaches a predetermined rotation speed (e.g., 350 rpm), closes the drain valve 6c. Note that the rotation speed of the inner tub 4 at this time is not limited to 350 rpm, as long as it is higher than the rotation speed in the washing process and the first tub cleaning process in the tub cleaning course described below, and lower than the high-speed rotation speed in the spin cycle.

The control device then alternately opens the detergent water supply solenoid valve and the shower water supply solenoid valve while keeping the drain valve 6c closed, allowing tap water to pool at the bottom of the outer tub 3. While allowing tap water to pool at the bottom of the outer tub 3, the control device maintains the rotation speed of the inner tub 4 at a relatively high 350 rpm, thereby causing the tap water to be drawn upward. When the shower water supply solenoid valve opens, as described above, tap water reaches the bellows cleaning nozzle 13b via the bellows cleaning water passage 13a and is sprayed toward the upper inner surface of the bellows 15, washing away lint adhering to the bellows 15. When the control device detects that the predetermined water level has been reached using a water level sensor or time control based on dynamic water pressure, it closes the shower water supply solenoid valve, but maintains the rotation speed of the inner tub 4 and continues to draw up tap water.

After a predetermined time, the control device opens the drain valve 6c while maintaining the rotation speed of the inner tub 4, allowing the lint-containing water to be drained without coming into contact with the clothes inside the inner tub 4, and the lint is collected by the water channel filter 6b. Once drainage is complete, the machine moves on to the spin cycle.

In this standard tub cleaning process, tap water is spun up to a relatively high position, washing away dirt and lint adhering to the upper part of the outer tub 3, including the outer tub cover 3a. Furthermore, the tap water spun up during the standard tub cleaning process reaches the air duct filter 7, and the water flow also washes away lint adhering to the front and rear of the air duct filter 7. In particular, during the standard tub cleaning process, the inner tub 4 rotates in the reverse direction (counterclockwise when viewed from the front), spun up tap water primarily toward the upper right side, efficiently cleaning the entire top edge of the air duct filter 7, located at the rear right side of the outer tub 3. Furthermore, since the standard tub cleaning process uses fresh water rather than wash water or rinse water, it is also possible to prevent lint from re-adhering. Furthermore, by spinning the inner tub 4 at a high speed of 900 rpm before rotating it at 350 rpm to spun up tap water, foaming during spun-up can be prevented, even if a small amount of detergent solution remains on the clothes before the tub cleaning process.

≪Dehydration process≫
During the spin cycle, the control device further increases the rotation speed of the inner tub 4 while keeping the drain valve 6c open, and rotates the inner tub 4 in the reverse direction at high speed (e.g., 1000 rpm) to (finally) spin out the water contained in the clothes. After the spin cycle has been performed for a predetermined time, the system transitions to the drying cycle.

≪Drying process≫
During the drying process, the control device opens the cooling water supply solenoid valve, energizes the hot air heater 5b, and drives the blower 5a to promote drying of the clothes. Specifically, air blown from the blower 5a is heated by the downstream hot air heater 5b and then supplied to the inner tub 4 through the hot air outlet 5c. The hot air supplied to the inner tub 4 removes moisture from the clothes, then passes through the through-holes in the inner tub 4, passes through the air duct filter 7, and reaches the circulation air duct 5d. The high-humidity air that flows into the circulation air duct 5d is dehumidified by the cooling water supplied from the cooling water supply solenoid valve and returns to the blower 5a through the air duct hose 5e.

<Operational behavior of washer-dryer during tub cleaning course>
In addition to the standard course of a washing operation including a washing step, a rinsing step, and a spin cycle, and a washing and drying operation including a drying step, the drum type washer-dryer of this embodiment can also be set to a tub cleaning course, which is a dedicated operation for cleaning the outer tub 3 and the like without putting clothes in. For example, if a drying operation including only the drying step without the washing step has been performed three times in a row, or if a clogged air duct filter 7 is detected during the drying operation due to a rise in temperature or a decrease in airflow, a message prompting the user to select the tub cleaning course is displayed on an operation panel (not shown) or the like.

Figure 11 is a flowchart showing the overall operation performed by the control device of a drum-type washer-dryer when the tub cleaning course is selected, and Figure 12 is a time chart showing the changes in the rotation speed of the inner tub and the changes in the operation of the circulation pump and drain valve during the tub cleaning course. When the tub cleaning course is set and the start button is operated on the operation panel, the control device sequentially executes the water supply process (step S11), first tub cleaning process (step S12), second tub cleaning process (step S13), draining process (step S14), third tub cleaning process (step S15), and spin-drying process (step S16), as shown in Figure 11. Each process is described in detail below.

≪Water supply process≫
First, the control device opens the detergent water supply solenoid valve with the drain valve 6c closed to supply water and accumulate tap water at the bottom of the outer tub 3. While repeatedly rotating the inner tub 4 forward and backward, the control device detects that the water level has reached a predetermined level based on the water level sensor, and then closes the detergent water supply solenoid valve.

<First tank cleaning process>
Once the water supply is complete, the control device drives the circulation pump 9 in the reverse direction, for example, at 1,500 rpm, while keeping the drain valve 6c closed, i.e., with tap water remaining in the outer tub 3. This generates a water flow at the bottom of the outer tub 3 in the direction indicated by the white arrows in Figures 4-6. Lint accumulated on the hot water heater 14 at the bottom of the outer tub 3 is discharged through the drain outlet 3b of the outer tub 3 into the internal drainage channel 6a and collected by the water channel filter 6b. In addition to cleaning the hot water heater 14, this water flow also serves to clean dirt from the inner surfaces of pipes and other components in the path indicated by the white arrows in Figures 4-6. During the first-tub-cleaning step, the inner tub 4 continues to rotate forward and backward from the water supply step, and its rotation speed (first rotation speed) is approximately the same as that of the washing step, for example, 40 to 50 rpm.

<Second tank cleaning process>
After a predetermined time has elapsed since the start of the first tank cleaning process (reverse rotation of the circulation pump 9), the process transitions to the second tank cleaning process. In the second tank cleaning process, as in the first tank cleaning process, the control device drives the circulation pump 9 in the reverse direction, for example, at 1500 rpm, while keeping the drain valve 6c closed, i.e., while tap water remains in the outer tub 3. However, in the second tank cleaning process, the inner tub 4 rotates in one direction (reverse direction) at a higher rotation speed (second rotation speed), for example, 100 rpm, than in the first tank cleaning process. Therefore, the tap water rises to a higher position than in the first tank cleaning process, washing away, for example, parts of the side and back surfaces of the outer tub 3 (e.g., the air duct filter 7). In particular, in the second tank cleaning process, the inner tub 4 rotates in the reverse direction, primarily toward the upper right, thereby efficiently cleaning the air duct filter 7, located at the rear right side of the outer tub 3, all the way up to the top.

≪Drainage process≫
After a predetermined time has elapsed since the start of the second tank cleaning process, the process transitions to the drainage process. In the drainage process, the control device stops the circulation pump 9 and opens the drain valve 6c to begin drainage. The control device then gradually increases the rotation speed of the inner tub 4, for example, from 100 rpm to 350 rpm while draining. During this process, lint washed from the front side of the air duct filter 7 during the second tank cleaning process is discharged directly into the internal drainage channel 6a, and lint washed from the back side of the air duct filter 7 is discharged into the internal drainage channel 6a via the lint discharge channel 8. The lint discharged into the internal drainage channel 6a is then collected by the channel filter 6b before reaching the drain valve 6c.

<Third tank cleaning process>
When the control device detects that draining is complete based on the water level sensor, it closes the drain valve 6c and proceeds to the third tub cleaning process. In the third tub cleaning process, the control device first keeps the drain valve 6c closed and alternately opens the detergent water supply solenoid valve and the shower water supply solenoid valve to collect tap water at the bottom of the outer tub 3. While collecting tap water at the bottom of the outer tub 3, the control device maintains the rotation speed of the inner tub 4 at 350 rpm, thereby sprinkling the tap water upward. When the shower water supply solenoid valve opens, as described above, tap water reaches the bellows cleaning nozzle 13b via the bellows cleaning water passage 13a and is sprayed toward the upper inner surface of the bellows 15, washing away lint adhering to the bellows 15. When the control device detects that the water level has reached a predetermined level using the water level sensor or time control based on dynamic water pressure, it closes the shower water supply solenoid valve, but maintains the rotation speed of the inner tub 4 and continues to sprinkle tap water. The rotation speed of the inner tub 4 (third rotation speed) is not limited to 350 rpm, as long as it is higher than the rotation speed in the second tub cleaning step and lower than the high-speed rotation speed in the spin-drying step.

In the third tank cleaning process, tap water is raised to high positions that could not be reached in the first and second tank cleaning processes, so dirt and lint adhering to the top of the outer tub 3, including the outer tub cover 3a, can also be washed away. Furthermore, at the end of the third tank cleaning process, the control device drives the circulation pump 9 in the reverse direction, for example at 1500 rpm, so that lint and other particles detached from the inner surface of the outer tub 3 during the third tank cleaning process are efficiently collected by the water channel filter 6b.

The control device then stops the circulation pump 9 and opens the drain valve 6c to begin draining the water, and the lint contained in the water collected in the third tank cleaning process is further collected by the water channel filter 6b. Once draining is complete, the machine moves on to the spin-drying process.

≪Dehydration process≫
During the spin-drying process, the control device further increases the rotation speed of the inner tub 4 while keeping the drain valve 6c open, and rotates the inner tub 4 in the reverse direction at high speed (e.g., 1000 rpm), thereby using centrifugal force to remove water adhering to the inner tub 4. After the spin-drying process has been performed for a predetermined time, the tub cleaning course ends.

<Effects of Example 1>
As described above, in this embodiment, even when the standard course is selected, the standard tank cleaning step is executed between the rinsing step and the spinning step, so that dirt adhering to the outer tub 3 and lint adhering to the air duct filter 7 can be washed away. However, when a drying operation is executed that does not include a washing step or the like and includes only a drying step, the standard tank cleaning step is not executed, so that dirt and lint accumulate on the outer tub 3 and the air duct filter 7. Therefore, when the drying operation is executed a predetermined number of times (e.g., three times) in succession, the tank cleaning course can be executed to wash away the accumulated dirt and lint in a shorter time than the standard course.

Furthermore, the water used in the first, second, and third tank cleaning steps of the tank cleaning course is clean water, not wash water or rinse water, which prevents dirt and lint from re-adhering. Furthermore, in the tank cleaning course, the circulation pump 9 is rotated in reverse to generate a strong water flow that is sucked into the water channel filter 6b at the bottom of the outer tub 3, concentrating lint in the water channel filter 6b and preventing lint from being discharged outside the machine when the drain valve 6c opens. If the circulation pump 9 were not driven, when the drain valve 6c opens, fine lint would not only be easily discharged outside the machine through the water channel filter 6b, but would also be likely to remain at the bottom of the outer tub 3. The lint remaining at the bottom of the outer tub 3 becomes even finer in the third tank cleaning step, where the rotation speed of the inner tub 4 is high, making it easier to discharge outside the machine. Furthermore, when the circulation pump 9 is rotated in the reverse direction, the strong water flow can remove lint and hairs that have accumulated on the hot water heater 14 at the bottom of the outer tub 3.
The lint collection operation may be performed before draining the water in the standard washing course. By driving the circulation pump 9 before draining the water, fine lint is collected in the water channel filter 6b, which prevents the lint from being discharged outside the machine and clogging the drain trap.

Example 2 relates to the control of the circulation pump 9 when stopping the water spray (circulation shower) from the water spray nozzle during the washing process or rinsing process.

As mentioned above, when spraying water from the spray nozzles, the circulation pump 9 rotates forward at a high speed, for example, 2500 rpm. As a comparative example, if the circulation pump 9 is suddenly stopped from rotating at high speed when spraying water, a large amount of water lifted by the circulation pump 9 still remains in the circulation water channel 11 when the pump stops. Figure 13 shows the water level of the circulation shower when the circulation pump stops in the comparative example. As shown in Figure 13, if the water level of the circulation shower is higher than the water surface level accumulated in the outer tub 3, immediately after the circulation pump 9 stops, water equivalent to this difference returns to the water surface level. As a result, a backflow occurs in the circulation pump 9, and the collected lint may overflow from the water channel filter 6b.

In this embodiment, the control device therefore gradually reduces the rotational speed of the circulation pump 9 when stopping the pump 9 while it is rotating in the forward direction, rather than suddenly stopping the high-speed circulation pump 9. The rotational speed can be reduced, for example, by reducing it from 2500 rpm by 500 rpm or 1000 rpm at predetermined time intervals until the pump is finally stopped, or by reducing it all at once from 2500 rpm to around 1000 rpm and stopping it after a predetermined time.

Figure 14 shows the water level of the circulating shower when the circulating pump is stopped in Example 2. When the control device drives the circulating pump 9 at a low speed, for example, around 1000 rpm, and then stops it, as shown in Figure 14, the water level of the circulating shower when the circulating pump is stopped will be lower than the height of the water surface accumulated in the outer tub 3. Therefore, even immediately after the circulating pump 9 is stopped, backflow to the circulating pump 9 is unlikely to occur, and the overflow of collected lint from the water channel filter 6b can be prevented. Note that if a decrease in the circulating flow rate of the circulating shower can be tolerated, the rotational speed of the circulating pump 9 may be set to 1000 rpm or less from the beginning.

Next, a modified example of Example 2 will be described. In this modified example, the control device controls the rotation speed of the circulation pump 9 based on the detection value of the water level sensor. Specifically, the relationship between the height of the water surface accumulated in the outer tank 3 and the target rotation speed of the circulation pump 9 is stored in advance as a table in the control device. The control device then controls the circulation pump 9 to reach the target rotation speed according to the detection value of the water level sensor, while ultimately stopping the circulation pump 9. This has the advantage of allowing the circulation pump 9 to be driven at the highest possible rotation speed before being stopped, within the range that prevents backflow after the circulation pump 9 is stopped.

The above-mentioned embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those that include all of the described configurations. For example, the above-mentioned tub cleaning process can be applied not only to drum-type washer-dryers, but also to vertical washer-dryers and washing machines without a drying function. It is also possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is also possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

1...drum type washer-dryer, 2...housing, 2a...door, 2b...front cover, 2c...side panel, 2d...rear cover, 2e...top cover, 2f...base, 2g...hinge, 3...outer tub, 3a...outer tub cover, 3b...drain outlet, 3c...inlet, 3d...recess, 3e...air intake, 4...inner tub, 4a...rotating shaft, 4b...through hole, 5...blower device, 5a...blower, 5b...hot air heater, 5c...hot air outlet, 5d...circulating air duct, 5e...air duct hose, 5f...auxiliary air duct filter 6...Drainage channel, 6a...Internal drainage channel, 6b...Water channel filter, 6c...Drain valve, 6d...Drainage hose, 7...Air channel filter, 8...Lint discharge channel, 8a...Lint discharge channel air channel side connection, 8b...Lint discharge channel drainage channel side connection, 9...Circulation pump, 10...Detergent dissolving channel, 11...Circulation channel, 12...Fluid balancer, 13...Bellows cleaning mechanism, 13a...Bellows cleaning channel, 13b...Bellows cleaning nozzle, 14...Hot water heater, 15...Bellows

Claims (5)

The housing and
an outer tank supported within the housing and configured to store water;
an inner tub that is contained in the outer tub and that stores clothes;
a circulation pump that circulates the water in the outer tank;
a water channel filter that collects lint contained in the water circulated by the circulation pump;
a drain valve for draining water from the outer tank;
a control device that controls the inner tank, the circulation pump, and the drain valve;
a blower for supplying air into the inner tank;
an air passage connecting the outer tank and the blower;
an air path filter provided in the air path to capture lint contained in the air ,
When the circulation pump rotates forward, water is sprayed into the inner tank from the top of the outer tank, and when the circulation pump rotates backward, water is guided to an inlet formed at the bottom of the outer tank,
When the control device detects that the air duct filter is clogged during the drying process, the control device outputs a display prompting the user to set a tub cleaning course different from a standard course including a washing process, a rinsing process, and a spin-drying process;
When the tank cleaning course is selected,
The control device executes a tank cleaning process in which the inner tank is rotated while the drain valve is closed and water is stored in the outer tank,
The tank cleaning step includes:
a first cleaning step in which the circulation pump rotates in a reverse direction while the inner tank rotates at a first rotation speed;
a second cleaning step in which the circulation pump rotates in a reverse direction and the inner tank rotates at a second rotation speed higher than the first rotation speed;
A washing machine characterized by having: The washing machine according to claim 1,
a hot water heater provided at the bottom of the outer tub to heat the water stored in the outer tub;
In the first washing step, lint adhering to the hot water heater is washed away. The washing machine according to claim 1,
The washing machine is characterized in that the water stirred up in the second cleaning step reaches the air path filter. The washing machine according to claim 1,
the tank cleaning step further includes a third cleaning step in which the inner tank is rotated at a third rotation speed higher than the second rotation speed;
The washing machine is characterized in that the water stirred up in the third washing step reaches an outer tub cover provided at an opening on the front side of the outer tub. The washing machine according to claim 4,
The washing machine is characterized in that the circulation pump rotates in reverse at the end of the third washing step.