CN111727281A

CN111727281A - Washing machine

Info

Publication number: CN111727281A
Application number: CN201980013230.2A
Authority: CN
Inventors: 胁田克也; 池水麦平
Original assignee: Panasonic Intellectual Property Management Co Ltd
Current assignee: Panasonic Intellectual Property Management Co Ltd
Priority date: 2018-04-16
Filing date: 2019-03-19
Publication date: 2020-09-29
Anticipated expiration: 2039-03-19
Also published as: WO2019202891A1; JP7398678B2; JPWO2019202891A1; CN111727281B; TW201945612A

Abstract

The washing machine of the present invention comprises: a drum (3) disposed in the water tank (2); a motor (7) that drives the drum (3); a water supply valve (9) for supplying washing water into the water tank (2); a drain valve (13) for discharging the washing water; a heater (19) that heats water in the water tank (2); and a control unit (22) for controlling the washing operation. The control unit (22) controls a tank cleaning operation for cleaning the water tank (2) and the drum (3), and the tank cleaning operation executes the following steps: a sterilization step of heating the water in the water tank (2) by a heater (19) and sterilizing the water tank (2) by the generated steam; a cleaning step of cleaning the inside of the water tank (2) after the sterilization step; and a water discharge step of discharging water in the water tank (2). This prevents the next washing from causing dirt and odor due to adhesion of bacteria and mold to the clothes.

Description

Washing machine

Technical Field

The present invention relates to a washing machine for washing laundry and the like.

Background

In general, a washing machine deposits detergent residue and dirt on an inner surface of a water tub and an outer surface of a washing tub due to long-term use. Thus, bacteria and mold propagate detergent residues and dirt as a nutrient source and in living places. Therefore, after washing, a part of unpleasant odor and dirt from the inside of the washing machine and the laundry may adhere to the washed laundry.

In recent years, there is a washing machine provided with a spraying function of spraying washing water to laundry to be washed in order to improve washing performance. The washing machine having this structure is provided with a circulating water passage for circulating the washing water in the water tank into the washing tank. However, since maintenance of the inside of the circulating water passage is difficult, fouling substances accumulate in the circulating water passage. Therefore, bacteria and mold may propagate as a living place and generate unpleasant odor. In addition, adhesion of bacteria/mold to laundry after washing, adhesion of metabolites of bacteria/mold, and adhesion of biofilm to laundry after washing may occur. As a result, the laundry may be soiled despite the washing.

In order to solve the above problem, the following washing machine has been proposed (for example, see patent document 1).

The washing machine described in patent document 1 first performs a tank cleaning step using a tank cleaning detergent or the like to clean the washing tank.

Subsequently, after the tank cleaning step, a sterilization step is performed. Specifically, the air in the washing tub is heated by the heating unit. Then, the air heated by the heating is sent into the washing tank through the air blowing part so that the temperature in the washing tank is high.

Then, in a state where the temperature in the washing tank is raised, a small amount of water is further supplied into the heating unit or the washing tank, and the inside of the washing tank is brought into a high-temperature and high-humidity environment. In this way, a method of sterilizing the inside of the washing tub has been proposed.

However, in the structure of the washing machine of patent document 1, the sterilization step is performed after the tank cleaning step is performed using a tank cleaning agent or the like. Therefore, the dirt such as bacteria and mold which is eliminated in the sterilizing step is retained on the wall surface of the washing tub. Then, in the next washing, a biofilm formed by the survival of bacteria and mold, the bacteria and mold that have been destroyed are peeled off from the wall surface of the washing tank. Thus, biofilm, bacteria, mold, and the like, which are attached again to laundry, may be a source of dirt and odor after washing.

In addition, in the tank cleaning step using the tank cleaning agent or the like, it is necessary to prepare a dedicated tank cleaning agent separately from the cleaning detergent. Further, since the time required for cleaning the tank is generally several hours, it is difficult to remove the bacteria/mold group in a state where the biofilm is formed and is growing. In this case, even when the tank cleaning agent contains a sterilizing component such as a bleaching agent, only partial sterilization can be performed.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2005-253584

Disclosure of Invention

The invention provides a washing machine capable of inhibiting dirt and peculiar smell generated by bacteria, mold and the like attached to clothes during washing.

The washing machine of the present invention comprises: a washing tank rotatably provided in the water tank; a motor for rotationally driving the washing tub; a water supply unit for supplying washing water into the water tank; a drain part for draining the washing water in the water tank; a heating unit that heats water stored in the water tank; and a control part for controlling the washing operation and the tank cleaning operation. The control unit is configured to execute the following steps in the tank cleaning operation: a sterilization step of heating the water stored in the water tank by the heating unit and sterilizing the water tank by the generated steam; a cleaning step of cleaning the inside of the water tank after the sterilization step; and a water discharge step of discharging water in the water tank.

According to this configuration, the temperature and humidity in the water tank can be increased by the steam generated in the water tank during the tank cleaning operation. Thus, bacteria and mold living on the surfaces of the water tank and the washing tank can be eliminated by using heat and moisture of a certain level or more. Then, the killed bacteria, mold, biofilm, etc. are washed and discharged to the outside of the machine. This can prevent bacteria, mold, biofilm, and the like from being detached from the water tank or the washing tank at the next washing. As a result, it is possible to suppress adhesion of bacteria, mold, biofilm, and the like to the laundry, and to wash the laundry into a clean state.

Drawings

Fig. 1 is a schematic configuration diagram of a washing machine according to embodiment 1 of the present invention.

Fig. 2 is a block diagram of the structure of the washing machine.

Fig. 3 is a time chart showing an operation in the tub cleaning operation of the washing machine.

Fig. 4 is a graph showing a relationship between the temperature of the washing machine and the sterilization effect.

Fig. 5 is a time chart showing operations of another example in the tank washing operation of the washing machine.

Fig. 6 is a schematic configuration diagram of a washing machine according to embodiment 2 of the present invention.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited to the embodiment.

(embodiment mode 1)

Fig. 1 is a schematic configuration diagram of a washing machine according to embodiment 1 of the present invention. Fig. 2 is a block diagram of the structure of the washing machine. Fig. 3 is a time chart showing an operation in the tub cleaning operation of the washing machine. Fig. 4 is a graph showing a relationship between the temperature of the washing machine and the sterilization effect.

The washing machine according to embodiment 1 is a so-called drum-type washing machine in which a rotary shaft 3a of a drum 3 serving as a washing tub 3 is arranged in a horizontal direction (including an inclination).

As shown in fig. 1, the washing machine according to embodiment 1 includes a casing 1, a water tank 2 elastically supported in the casing 1, and the like. Water tub 2 includes a drum 3 provided rotatably as a washing tub 3 and having a closed bottom. The rotary shaft 3a of the drum 3 is disposed at an angle θ (for example, 10 degrees) inclined forward and upward (upward left direction in the drawing).

Hereinafter, the door 25 side, the motor 7 side, the detergent box 10 side, and the drain path 12 side will be described as front, rear, upper, and lower sides, respectively.

The drum 3 is provided with a plurality of protrusions 4 protruding inward toward the rotation center of the drum 3 and a plurality of small holes 5 communicating with the inside of the water tank 2 on the inner circumferential side surface. The drum 3 further includes an opening portion 6 provided on the front surface side. A user can insert laundry (hereinafter, sometimes referred to as "laundry") such as laundry into drum 3 and take the laundry out of drum 3 through opening 6.

The water tub 2 includes a motor 7, and the motor 7 is attached to a rear surface and rotationally drives the drum 3. The motor 7 is, for example, a brushless dc motor that performs inverter control. The motor 7 is driven to a freely variable rotation speed by frequency conversion control.

A water supply pipe 8 for supplying washing water into the water tub 2 is connected to a faucet (not shown) of a tap water pipe, for example, and is provided with a water supply valve 9 as a water supply unit. The water supply pipe 8 is connected to a detergent box 10 for feeding detergent. The detergent box 10 is connected to the water tank 2 through a water supply passage 11. Thereby, the washing water flows from the water supply pipe 8 through the detergent box 10 and the water supply passage 11 and is supplied into the water tub 2. In addition, the washing water includes not only water in which detergent is dissolved but also water in a simple sense.

The washing water supplied into the tub 2 is discharged to the outside of the washing machine through the drainage path 12.

The drain path 12 includes a drain valve 13 as a drain unit and a drain filter 14. That is, when the drain valve 13 is opened, the washing water is discharged from the drain port 15 provided at the bottom of the tub 2 to the outside of the washing machine through the drain filter 14 and the drain valve 13. The drain filter 14 is provided at a position where the washing water circulates during the washing for trapping, for example, buttons or the like detached from the object to be washed. The drain filter 14 is configured to be detachable from the front surface side of the housing 1.

Circulating water passage 16 is disposed to guide the washing water in water tub 2 from water discharge port 15 of water tub 2 to opening 6 side of drum 3 located at the front portion in water tub 2. The circulating water passage 16 includes a pump 17 for circulating the washing water and a discharge port 18. The pump 17 is provided at the bottom in the casing 1 and is disposed downstream of the drain filter 14. The washing water in water tub 2 is discharged from discharge port 18 into drum 3 by driving of pump 17.

The heater 19 constitutes a heating portion that heats the water accumulated in the water tank 2, and is disposed at the bottom in the water tank 2. When a predetermined amount of water is accumulated in the water tank 2, the heater 19 is disposed at a position submerged in the water.

The water amount detector 20 detects the amount of the washing water supplied into the water tub 2. The temperature detection unit 21 is disposed near the front surface of the upper part of the water tank 2, and detects the temperature near the upper part of the water tank 2. The temperature detection unit 21 is formed of, for example, a thermistor.

The cloth amount detecting unit 23 detects the amount of the object to be cleaned put into the drum 3. The rotation detecting unit 24 detects a driving amount of the drum 3 such as a rotation speed.

The control unit 22 is disposed in the casing 1, and controls various components based on input information to perform a washing operation, a tub cleaning operation, and the like.

Specifically, as shown in fig. 2, the control unit 22 receives information such as the amount of the object to be washed detected by the cloth amount detection unit 23, the amount of the washing water detected by the water amount detection unit 20, the temperature in the water tank 2 detected by the temperature detection unit 21, and the driving amount (e.g., the number of revolutions) of the drum 3 detected by the revolution detection unit 24.

Then, the control unit 22 controls the motor 7, the water supply valve 9, the drain valve 13, the pump 17, the heater 19, and the like based on these input information, and sequentially controls the washing step, the rinsing step, the spin-drying step, and the like to perform the washing operation.

The controller 22 also performs a tank cleaning operation, which will be described later, to clean the water tank 2, the drum 3, the circulating water passage 16, and the like.

When the washing machine is used, the user first opens the door 25 openably and closably provided on the front surface of the casing 1. This enables the objects to be washed to be taken out and put in from the opening 6 of the drum 3 provided on the front surface side of the drum 3.

Further, the operation display portion 26 is provided at an upper portion of the front surface side of the housing 1. The user inputs settings for operating the washing machine via the operation display unit 26. The setting input by the operation display unit 26 is output to the control unit 22. Thus, the control unit 22 executes the washing operation, the tank cleaning operation, and the like based on the inputted setting contents. The operation display unit 26 obtains and displays the setting contents and the operating conditions of the washing machine from the control unit 22. This enables the user to grasp the setting contents, the operating conditions, and the like, and to correct the setting contents as needed.

The washing machine according to embodiment 1 is configured as described above.

Hereinafter, operations and actions of the washing machine in the washing operation and the tub washing operation will be described with reference to fig. 1 to 4.

First, the operation and action in the washing operation for washing the laundry as the object to be washed will be described.

In the washing operation, the user opens the door 25 and puts the object to be washed into the drum 3 through the opening 6.

Next, the user turns ON (ON) a power switch (not shown) of the operation display unit 26, and presses a start switch (not shown), for example. Thereby, the washing operation including the washing step, the rinsing step, the dehydrating step, and the like is sequentially started.

In the washing operation, a washing step is first performed.

When the washing step is started, the control unit 22 first detects the amount (e.g., weight) of the object to be washed put into the drum 3 by the cloth amount detection unit 23. Specifically, when the drum 3 is rotationally driven by the motor 7, the cloth amount detection unit 23 detects the amount of the object to be cleaned based on the amount of torque applied to the motor 7, the current value of the motor 7, and the like.

Next, the control unit 22 sets the amount of water to be supplied into the water tank 2 based on the amount of the object to be cleaned detected by the cloth amount detection unit 23. The control unit 22 sets the time for executing each step such as the washing step, the rinsing step, and the spin-drying step. The control unit 22 determines a target detergent amount based on a detergent amount preset in accordance with the amount of the object to be cleaned, and displays the target detergent amount on the operation display unit 26. The user introduces detergent or the like into the detergent box 10 in accordance with the target amount of detergent displayed on the operation display unit 26.

Subsequently, control unit 22 opens water supply valve 9. Thus, water supplied from the water supply pipe is supplied into water tub 2 through water supply pipe 8, detergent box 10, and water supply passage 11. At this time, the drain valve 13 is closed. That is, the water introduced into the detergent box 10 through the water supply pipe 8 dissolves the detergent in the detergent box 10 to generate the washing water. The generated washing water is supplied into water tub 2 through water supply passage 11 and is accumulated in the bottom of water tub 2. The washing water accumulated at the bottom flows into drum 3 through small holes 5 in the outer circumferential side surface of drum 3.

Next, the controller 22 detects the amount of water supplied into the water tank 2 by the water amount detector 20. Then, when the amount of water preset according to the amount of the object to be washed is the same as the amount of water supplied, the control unit 22 closes the water supply valve 9. At this time, the control section 22 drives the drum 3 to rotate in one direction at, for example, a rotation speed of 20rpm by the motor 7 during the water supply so that the object to be washed rotates in the drum 3. This accelerates the permeation of the washing water into the object to be washed. At this time, since the washing water is absorbed by the object to be washed, the amount of water in the water tub 2 is generally lower than the set water level. Therefore, controller 22 opens water supply valve 9 again to replenish water into water tub 2 to return to the set water level. In addition, the water level is not lower than the set water level, and is not limited to this.

Next, when the water supply to the water tank 2 is completed, the controller 22 drives the pump 17. This leads the water accumulated in the bottom of the water tank 2 from the drain port 15 to the circulating water passage 16. The water guided to the circulating water passage 16 flows in the circulating water passage 16. Then, the water is discharged from discharge port 18 of circulating water passage 16 into drum 3. The sprayed washing water flows out of small hole 5 of drum 3 into water tub 2, and circulates again through a path from drain port 15 through circulating water passage 16. Thereby, the washing water sufficiently permeates into the object to be washed.

Subsequently, the control unit 22 performs so-called beat washing of the object to be washed. Specifically, the drum 3 is driven by the motor 7 to rotate forward and backward alternately at a predetermined rotational speed (e.g., 42rpm) for a predetermined time (e.g., 15 seconds), thereby performing the beat washing. In the beat washing, the object to be washed is first lifted by the protrusions 4 in the rotation direction of the drum 3. After that, the object to be washed drops from the upper portion inside the drum 3 after being lifted. Thereby, the object to be cleaned is cleaned.

Then, the control unit 22 executes the above-described washing step for a set predetermined time (for example, 10 minutes). Thereafter, the controller 22 opens the drain valve 13 to discharge the washing water from the washing machine to the outside of the machine. This completes the washing step of the washing operation.

Next, after the washing step is completed, the control unit 22 sequentially executes the rinsing step and the spin-drying step. Then, the control unit 22 ends the washing operation.

The detailed description of the rinsing step and the spin-drying step is the same as that of the conventional washing machine, and thus is omitted.

Hereinafter, the tub washing operation of the washing machine will be described with reference to fig. 3.

Fig. 3 is a time chart showing an operation in the tank washing operation of the washing machine according to embodiment 1.

The tub cleaning operation is an operation for cleaning the water tub 2, the drum 3, the circulating water passage 16, and the like, which is performed separately from the above-described washing operation.

Specifically, as shown in fig. 3, the tank cleaning operation includes steps such as a sterilization step, a cleaning step, and a drain step, and these steps are sequentially executed.

The user first turns on a power switch (not shown) of the operation display unit 26 to set the tank cleaning operation. After the setting, the user operates a start switch (not shown). This starts the tank cleaning operation.

In the tank cleaning operation, a sterilization step is first performed.

When the sterilization step starts, the controller 22 opens the water supply valve 9. Thus, water supplied from the water supply pipe is supplied into water tub 2 through water supply pipe 8, detergent box 10, and water supply passage 11. At this time, during the tank washing operation, no detergent is put into the detergent box 10. Therefore, only water containing no detergent is supplied into water tub 2 and is accumulated in the bottom of water tub 2. The water accumulated at the bottom flows into the drum 3 through the small holes 5 on the outer peripheral side surface of the drum 3.

Next, the controller 22 detects the amount of water supplied into the water tank 2 by the water amount detector 20. At this time, the amount of water to be supplied is set to two levels, for example, a "low" water level and a "high" water level in each step of the tank cleaning operation in embodiment 1, and is set to a "low" water level in the sterilization step. The "low" water level corresponds to the amount of water that submerges the heater 19 in the supplied water. When the water level after water supply is detected by the water amount detection unit 20 as a "low" water level as a set amount, the control unit 22 closes the water supply valve 9.

After the water supply, the controller 22 energizes the heater 19 to heat the water accumulated in the bottom of the water tank 2. Specifically, the controller 22 controls the energization of the heater 19 based on the output (detected temperature) of the temperature detector 21 provided in the vicinity of the front surface of the upper portion of the water tank 2. This evaporates the water, and steam is generated in the water tank 2. The inside of the water tank 2 is heated by the steam generated in the water tank 2.

The controller 22 controls energization of the heater 19 based on the output of the temperature detector 21 so that the temperature (surface temperature) of the upper inner surface of the water tank 2 becomes the set temperature T1. The set temperature T1 is, for example, preferably 50 ℃ or higher, more preferably 50 ℃ or higher and 90 ℃ or lower.

In addition, when bacteria are removed from mold or bacteria, it is more advantageous to set the set temperature T1 higher. However, when the set temperature T1 is set to a high temperature, it is necessary to consider the heat-resistant temperature of the resin material that is the structural body of the washing machine. It takes time to heat the water supplied into the water tank 2 to the high set temperature T1. Therefore, the set temperature T1 is set within the above temperature range for the reason that the same effect as that at high temperature can be exhibited even at low temperature in a shorter time.

Here, the relationship between the heating temperature and the holding time for mold and the sterilization effect will be described with reference to fig. 4.

Fig. 4 is a graph showing the relationship between the heating temperature and the holding time for mold and the sterilization effect. Each heating temperature shown in fig. 4 has a magnitude relationship of temperature a < temperature b < temperature c. Specifically, for example, the temperature a is 45 ℃, the temperature b is 48 ℃, and the temperature c is 50 ℃.

As shown in fig. 4, it is understood that the higher the heating temperature is, the higher the sterilization effect can be obtained in a shorter time. Further, the lower the heating temperature, the longer the time required for the elimination of mold and bacteria.

That is, it was confirmed that the higher the heating temperature, the more advantageous the number of the mold and bacteria survived was, the smaller the number of the mold and bacteria survived was, the more two-digit. Therefore, in embodiment 1, the set temperature T1 is set to 50 ℃.

As shown in fig. 3, when the temperature detector 21 detects that the temperature of the upper inner surface of the water tub 2 reaches the set temperature T1(50 ℃), the controller 22 controls the amount of energization and the energization time for energizing the heater 19 so that the set temperature T1 is maintained for a predetermined time. In this case, when the set temperature T1 is 50 ℃, the predetermined time to be maintained is desirably, for example, about 10 minutes. When the set temperature is 55 ℃, the predetermined time to be maintained is preferably, for example, about 5 minutes. This makes it possible to take into consideration the heat-resistant temperature of the resin material, and to exhibit a high bacteria-removing effect against mold and bacteria in a shorter time and at a low temperature as well as at a high temperature.

In addition, in the washing machine of embodiment 1, the temperature detection unit 21 is provided on the upper front surface of the water tub 2. That is, the temperature of the portion farthest from the place where the water is heated at the bottom of the water tank 2 is detected. Thus, the controller 22 can reliably heat the entire interior of the water tank 2 to at least the set temperature T1 or higher.

At this time, the controller 22 drives the drum 3 to rotate in one direction at a low speed of, for example, 40rpm while heating the water accumulated in the bottom of the water tank 2. This causes the drum 3 to increase in temperature by contacting with the heated water. The drum 3 having the increased temperature rotates in the water tank 2. Thus, the upper part of the water tank 2, which is far from the water heated by the heater 19, can be heated by the heat radiated from the drum 3 after the temperature is raised. That is, the temperature difference between the upper and lower portions of the water tank 2 is reduced. As a result, the steam generated from the heated water does not condense (condense) even if it contacts the water tank 2 in the low-temperature portion. Therefore, the temperature in the water tank 2 can be raised more quickly.

The water heated by the heater 19 is stirred by the rotation of the drum 3. This makes the temperature of the water in the water tank 2 uniform. As a result, the release of the vapor evaporated from the surface of the water is further promoted.

In the above state, the control unit 22 drives the pump 17. Thus, the water in the water tank 2 heated by the heater 19 flows to the circulating water passage 16 and is discharged from the discharge port 18 into the water tank 2. That is, the heated water is circulated. Specifically, water in the water tank 2 heated by the heater 19 is sucked from the water discharge port 15 provided in the bottom of the water tank 2 by driving the pump 17. The sucked water is guided to the circulating water passage 16 after passing through the drain filter 14. The water guided to the circulating water passage 16 is ejected from the ejection port 18 into the drum 3. The water discharged into drum 3 then flows out of small hole 5 of drum 3 into water tank 2, and is circulated again through a path from water discharge port 15 through circulating water passage 16.

That is, in the sterilization step of the tank washing operation, heated water (hereinafter, sometimes referred to as "heated water") is circulated through a path passing through the circulation water passage 16 from the drain port 15. This makes it possible to destroy bacteria and mold living in the path passing through the circulating water passage 16. As a result, bacteria and mold that survive the pathway can be more reliably sterilized. In this case, it is preferable to drive the pump 17 at a low speed to bring bacteria and mold into contact with the heated water for a long time. Specifically, it is preferable to drive the pump 17 so that the heating water flows at a speed of such a degree that the heating water does not stop flowing in the path passing through the circulating water passage 16. The pump 17 may be driven continuously or intermittently.

The control unit 22 executes the sterilization step for a predetermined time (for example, 30 minutes).

Next, the control unit 22 executes a cleaning step of the tank cleaning operation subsequent to the sterilization step.

The cleaning step is as follows: the dirt such as bacteria, mold, and biofilm eliminated in the sterilizing step is peeled off from the wall surfaces of the water tank 2 and the drum 3 and washed.

Specifically, the control unit 22 first stops the energization of the heater 19. Then, control unit 22 opens water supply valve 9 to supply water into water tub 2. At this time, the water level after the water supply is set to a "high" water level higher than the "low" water level at the time of the sterilization step as shown in fig. 3. This enables the inner surface of the upper side of the water tank 2 to be washed away as described later. The "high" water level is a water level corresponding to a state where the lower portion of the rear of the drum 3 is sufficiently immersed in water, and is, for example, a water level where the central portion of the outer peripheral wall of the inclined drum 3 is sufficiently immersed in water.

When the water level after water supply is detected by the water amount detection unit 20 as a "high" water level as a set amount, the control unit 22 closes the water supply valve 9. Thus, the lower portion of the rear of the drum 3 is sufficiently immersed in water.

Subsequently, the control unit 22 drives the motor 7 to rotate the drum 3 at a high speed (for example, 100 rpm). At this time, the water in water tub 2 increased to the "high" water level by the water supply is rolled up by the high-speed rotation of drum 3, and reaches the upper inner surface of water tub 2.

Thereby, the dirt such as bacteria, mold, and biofilm on the upper surface of the water tub 2, which is eliminated in the sterilizing step, is peeled off from the wall surfaces of the water tub 2 and the drum 3 by the rolled water. As a result, the dirt such as bacteria, mold, and biofilm that has adhered to the upper surface of the water tank 2 and has been eliminated can be washed away more reliably.

In this way, in the washing step of the tank washing operation, the temperature of the heated water is lowered by supplying water into the water tank 2 to mix tap water at normal temperature with the heated water in which steam is generated in the sterilization step. This allows the drum 3 to rotate at a high speed in consideration of the heat-resistant temperature of the resin material.

When the water level after water supply is detected to be "high" as a set amount by the water amount detector 20, the controller 22 closes the water supply valve 9 and drives the pump 17. Thereby, the water in the water tank 2 flows through the circulating water passage 16 and circulates. As a result, the dirt such as bacteria, mold, and biofilm that has adhered to the wall surface in the circulating water passage 16 and has been eliminated in the sterilization step is peeled off from the wall surface in the circulating water passage 16.

Then, the control unit 22 executes the above-described washing step for a predetermined time (for example, 30 minutes).

Here, the operation of another example of the cleaning step in the tank cleaning operation according to embodiment 1 will be described with reference to fig. 5.

Fig. 5 is a timing chart showing operations of another example in the tank cleaning operation according to embodiment 1. In other examples, the operation of the cleaning step is different from that of embodiment 1 shown in fig. 3.

Specifically, the other example differs from the operation of the one-time washing step of embodiment 1 shown in fig. 3 in that the water level in water tub 2 and the rotation speed of drum 3 are set a plurality of times in the washing step of the tub washing operation.

That is, as shown in fig. 5, the control section 22 first stops energization of the heater 19 in the cleaning step. Then, controller 22 opens water supply valve 9 to supply water into water tub 2. At this time, in each step of the tank cleaning operation according to the other example, as shown in fig. 5, the amount of water to be supplied is set to three levels, for example, a "low" water level, a "medium" water level, and a "high" water level, and is first set to the "medium" water level in the cleaning step. That is, the water level of the water supplied in the washing step is higher than the "low" water level in the sterilizing step, and is set in a two-stage structure of the "medium" water level and the "high" water level. In the washing step of another example, the rotation speed of drum 3 is set to "low speed", "medium speed", and "high speed" according to the water level. In the following, an example is described in which the water level in the washing step is changed in a two-stage structure, but the water level may be changed in a three-stage structure or more.

First, when the "middle" water level corresponding to the first stage in the water tank 2 is detected by the water amount detection part 20, the control part 22 closes the water supply valve 9. Then, the controller 22 controls the motor 7 to rotate the drum 3 at a medium speed (for example, 80 rpm). Thereby, the water in the water tub 2 increased to the "middle" water level by the water supply is rolled up by the rotation of the drum 3. As a result, the rolled water peels off the dirt such as bacteria, mold, and biofilm that has been eliminated in the sterilizing step from the wall surfaces of the water tub 2 and the drum 3.

Subsequently, the control unit 22 drives the pump 17. Thereby, the water in the water tank 2 flows through the circulating water passage 16 and circulates. At this time, dirt such as bacteria, mold, and biofilm that has adhered to the wall surface in the circulating water passage 16 and has been eliminated in the sterilization step is peeled off from the wall surface in the circulating water passage 16.

Then, after a predetermined time has elapsed since the "medium" water level was detected by the water amount detector 20, the controller 22 opens the water supply valve 9 again to supply water into the water tank 2. When the "high" water level corresponding to the second stage in water tub 2 is detected by water amount detector 20, controller 22 closes water supply valve 9. At this time, when the water is accumulated to the "high" level in the water tank 2, the lower portion of the drum 3 is sufficiently immersed in the water as described above.

When the water level detecting unit 20 detects the "high" water level, the control unit 22 stops driving the pump 17.

Then, in a state where the water level is "high" by a set amount, the controller 22 drives the motor 7 to rotate the drum 3 at a high speed (e.g., 100 rpm). Thereby, the water in water tub 2 is further rolled up by the high-speed rotation of drum 3, and reaches the uppermost inner surface of water tub 2. As a result, the rolled water effectively peels off dirt such as bacteria, mold, and biofilm from the wall surfaces of the water tub 2 and the drum 3, and washes the dirt. At this time, the control unit 22 stops driving the pump 17, and thus the water in the water tank 2 cannot flow into the circulating water passage 16. Therefore, the water level in the water tank 2 is maintained in a "high" state. This can sufficiently secure the amount of water that is rolled up by the high-speed rotation of the drum 3. As a result, the flushing effect can be further improved.

The control unit 22 executes the cleaning step of the tank cleaning operation according to the other example for a predetermined time (for example, 30 minutes).

As described above, the operation of the cleaning step in the tank cleaning operation according to embodiment 1 and the other examples is completed.

Next, the control unit 22 executes the water discharge step subsequent to the cleaning step of embodiment 1 and other examples. Since the tank cleaning operation in embodiment 1 and the other examples is the same except for the operation in the cleaning step, the water discharge step is not distinguished, and the description is made with reference to fig. 3 and 5.

In the water discharge step, the control section 22 first opens the water discharge valve 13. Thereby, the water in the water tank 2 and the circulating water passage 16 containing the dirt such as bacteria, mold, and biofilm eliminated in the sterilizing step is discharged through the water discharge passage 12.

After the water is drained, the controller 22 controls the motor 7 to rotate the drum 3 at a higher speed (for example, 300rpm) for a short time (for example, 5 minutes) than in the high-speed rotation in the washing step. Thereby, water droplets and the like adhering to drum 3 are blown into water tub 2 by centrifugal force. The blown water droplets fall to the drain port 15 of the water tank 2 and are discharged to the outside of the machine through the drain path 12.

Then, the control unit 22 closes the drain valve 13 to end the tank cleaning operation.

As described above, the washing machine of embodiment 1 includes: a drum 3 rotatably provided in the water tub 2; a motor 7 for rotationally driving the drum 3; a water supply valve 9 for supplying washing water into the water tub 2; a drain valve 13 for draining the washing water in the water tank 2; a heater 19 that heats the water stored in the water tank 2; and a control unit 22 for controlling the washing operation and the tank cleaning operation. The control unit 22 is configured to execute the following steps during the tank cleaning operation: a sterilization step of heating the water stored in the water tank 2 by the heater 19 and sterilizing the water tank 2 by the generated steam; a cleaning step of cleaning the inside of the water tank 2 after the sterilization step; and a water discharge step of discharging water in the water tank 2.

With this configuration, during the tank cleaning operation, the temperature and humidity in the water tank 2 can be increased by the steam generated in the water tank 2. Thus, bacteria and mold living on the surfaces of the water tank 2 and the drum 3 can be destroyed by heat and moisture of a certain level or more. Then, the killed bacteria, mold, biofilm, and the like are washed and discharged to the outside of the machine. This can prevent bacteria, mold, biofilm, and the like from being peeled off from the water tub 2 and the drum 3 at the next washing. As a result, it is possible to prevent bacteria, mold, biofilm, and the like from adhering to the laundry, and to wash the laundry into a clean state.

Further, in the sterilization step, the controller 22 controls the heater 19 based on the output of the temperature detector 21 for detecting the temperature of the water tank 2, and heats the upper portion of the water tank 2 to a predetermined temperature. This optimizes the amount of steam generated in the water tank 2, and enables living bacteria and mold to be efficiently killed.

Further, the control unit 22 maintains the predetermined temperature for a predetermined time. Thereby, the generated steam is distributed throughout the entire water tub 2. As a result, bacteria and mold living in the entire water tank 2 can be more reliably destroyed by the steam.

Further, in the sterilization step, the controller 22 stirs the heated water stored in the water tank 2 by the rotational driving of the drum 3. This uniformly heats the water accumulated in the bottom of the water tank 2. Then, the heat of the heated water is transferred to the entire drum 3 by the stirring. This allows the temperature in water tub 2 to be raised quickly by releasing heat from the entire drum 3 heated by heat transfer. That is, the temperature in water tub 2 can be efficiently increased, and the temperature in water tub 2 can be rapidly equalized. This can more reliably prevent the occurrence of condensation of steam due to a cold portion in the water tank 2. As a result, the steam can be efficiently distributed throughout the entire water tub 2.

In addition, the washing machine of embodiment 1 further includes: a circulating water passage 16 provided to guide water in the water tank 2 from the bottom of the water tank 2 into the drum 3; and a pump 17 for circulating the water in the water tank 2 through the circulating water passage 16. Then, the controller 22 drives the pump 17 during the tank cleaning operation to circulate the water in the water tank 2 through the circulating water passage 16.

This causes the heated water to flow into the circulating water passage 16, thereby destroying bacteria and mold living in the circulating water passage 16. The sterilized dirt such as bacteria, mold, and biofilm can be peeled off from the circulating water passage 16 and discharged to the outside of the machine. This makes it possible to clean the inner surface of the piping around water which has a high humidity and is likely to be a living place for bacteria and mold. As a result, the reattachment of the dirt to the object to be cleaned during the next washing can be suppressed.

(embodiment mode 2)

Fig. 6 is a schematic configuration diagram of a washing machine according to embodiment 2 of the present invention. The washing machine of embodiment 2 is different from the drum-type washing machine of embodiment 1 in that it is configured by a so-called vertical washing machine.

That is, the rotation axis of washing tub 3 of the washing machine of embodiment 2 is set in the vertical direction. Since other configurations are the same as those in embodiment 1, the same reference numerals are given to the same configurations, and the detailed description is given with reference to embodiment 1.

As shown in fig. 6, washing tub 3 of the washing machine according to embodiment 2 is rotatably provided in water tub 2. A stirring blade 27 is rotatably provided at the bottom of the washing tub 3. The stirring blade 27 is rotationally driven by the motor 7 to stir the washing water stored in the water tank 2.

The heater 19 is disposed at the bottom of the water tank 2 and heats the washing water stored in the water tank 2. The temperature detector 21 is disposed above the water tank 2 and detects the temperature in the water tank 2.

In the vertical washing machine according to embodiment 2, as in embodiment 1, the control unit 22 controls the washing operation and the tub cleaning operation for cleaning the water tub 2, the washing tub 3, and the like.

Further, as in embodiment 1, the tank cleaning operation is composed of the respective steps such as the sterilization step, the cleaning step, and the water discharge step, and the respective steps are sequentially executed.

That is, in the sterilization step of the tank cleaning operation, the control unit 22 energizes the heater 19 based on the output of the temperature detection unit 21. Thereby, the water stored in the water tank 2 is heated to generate steam. The inside of the water tank 2 is heated by the generated steam.

At this time, when the temperature of the inner surface of the upper portion of the water tank 2 detected by the temperature detector 21 reaches the set temperature by the steam, the controller 22 controls the energization of the heater 19 so that the set temperature is maintained for a predetermined time. Then, bacteria, mold, and the like living on the wall surfaces of the water tank 2 and the washing tank 3 are destroyed by the steam having the set temperature or higher.

Next, the control unit 22 executes a cleaning step executed subsequent to the sterilization step.

In the cleaning step, controller 22 first opens water supply valve 9 to supply a predetermined amount of water into water tub 2. When it is detected by the water amount detector 20 that the water level after water supply has become the set water level, the controller 22 closes the water supply valve 9. Next, the control unit 22 drives the stirring blade 27 to rotate at a high speed. As a result, water is attached to the inner circumferential surface of the water tank 2 by centrifugal force generated by the water flow generated in the water tank 2, and the periphery of the water surface rises in a V-shape. At this time, the dirt such as bacteria, mold, and biofilm that has been eliminated in the sterilization step and has adhered to the water tank 2 is washed off from the water tank 2 by the water that rises in the V-shape.

Next, the control section 22 executes a water discharge step.

In the drain step, the controller 22 opens the drain valve 13 to drain the water in the water tank 2 to the outside of the washing machine through the drain path 12.

In embodiment 2, the configuration in which the stirring blade 27 is rotationally driven independently of the washing tub 3 has been described as an example, but the present invention is not limited to this. For example, the stirring blade 27 may be configured to be rotationally driven integrally with the washing tub 3.

As described above, the washing machine of the present invention includes: a washing tank rotatably provided in the water tank; a motor for rotationally driving the washing tub; a water supply unit for supplying washing water into the water tank; a drain part for draining the washing water in the water tank; a heating unit for heating the water stored in the water tank; and a control part for controlling the washing operation and the tank cleaning operation. The control unit is configured to execute the following steps in the tank cleaning operation; a sterilization step of heating the water stored in the water tank by the heating unit and sterilizing the water tank by the generated steam; a cleaning step of cleaning the inside of the water tank after the sterilization step; and a water discharge step of discharging water in the water tank.

According to this configuration, the temperature and humidity in the water tank can be increased by the steam generated in the water tank during the tank cleaning operation. Thus, bacteria and mold living on the surfaces of the water tank and the washing tank can be eliminated by using heat and moisture of a certain level or more. The killed bacteria, mold, biofilm, and the like are washed and discharged to the outside of the machine. This can prevent bacteria, mold, biofilm, and the like from being peeled off from the water tank or the washing tank at the next washing. As a result, it is possible to prevent bacteria, mold, biofilm, and the like from adhering to the laundry, and to wash the laundry into a clean state.

In addition, the following structure is desirable: in the sterilization step, the control unit of the washing machine controls the heating unit based on the output of the temperature detection unit for detecting the temperature of the water tank, and heats the upper portion of the water tank to a predetermined temperature.

This optimizes the generation of steam in the water tank, and efficiently eliminates viable bacteria and mold.

In addition, the following structure is desirable: the control part of the washing machine of the invention maintains the specified temperature for the specified time.

Thereby, the steam is distributed throughout the entire water tub 2 in the water tub. As a result, bacteria and mold living in the entire water tank 2 can be more reliably destroyed by the steam.

In addition, the washing machine of the present invention is desirably configured as follows: the control unit stirs the heated water stored in the water tank by the rotational driving of the washing tank in the sterilization step.

This heats the heated water accumulated in the bottom of the water tank uniformly. And, the heat of the heated water is transferred to the entire washing tub by the agitation. Thus, the temperature in the water tub can be raised quickly by releasing heat from the entire washing tub heated by heat transfer. That is, the temperature in the water tank can be efficiently increased and rapidly equalized. This can more reliably prevent the occurrence of condensation of steam due to a cold portion in the water tank. As a result, the steam can be efficiently distributed throughout the entire water tank.

In addition, the washing machine of the present invention further includes: a circulating water passage configured to guide water in the water tank from a bottom of the water tank into the washing tank; and a pump for circulating the water in the water tank through the circulating water passage. Moreover, the following structure is desirable: the control unit drives the pump during the tank cleaning operation to circulate the water in the water tank through the circulation water passage.

According to this configuration, the heated water is caused to flow into the circulating water passage, thereby eliminating bacteria and mold living in the circulating water passage. In addition, the sterilized dirt such as bacteria, mold, and biofilm can be peeled off from the circulating water passage and discharged to the outside of the machine. This makes it possible to clean the inner surface of the piping around water which has a high humidity and is likely to be a living place for bacteria and mold. As a result, the adhesion of dirt to the clothes can be suppressed again in the next washing.

Industrial applicability

The present invention is useful for a washing machine or the like which suppresses adhesion of bacteria, mold, biofilm, and the like to an object to be washed during washing and is expected to realize clean washing of the object to be washed.

Description of the reference numerals

1: a housing; 2: a water tank; 3: a drum (washing tub); 3 a: a rotating shaft; 4: a protrusion body; 5: a small hole; 6: an opening part; 7: an electric motor; 8: a water supply pipe; 9: a water supply valve (water supply part); 10: a detergent box; 11: a water supply passage; 12: a drainage path; 13: a drain valve (drain unit); 14: a drain filter; 15: a water outlet; 16: a circulating water passage; 17: a pump; 18: an ejection port; 19: a heater (heating unit); 20: a water amount detection unit; 21: a temperature detection unit; 22: a control unit; 23: a cloth amount detection unit; 24: a rotation detection unit; 25: a door; 26: an operation display unit; 27: stirring wings.

Claims

1. A washing machine is provided with:

a washing tank rotatably provided in the water tank;

a motor for rotationally driving the washing tub;

a water supply unit for supplying washing water into the water tank;

a drain part for draining the washing water in the water tank;

a heating unit that heats the water stored in the water tank; and

a control part for controlling the washing operation and the tank cleaning operation,

wherein the control unit executes the following steps in the tank cleaning operation: a sterilization step of heating the water stored in the water tank by the heating unit and sterilizing the water tank by the generated steam; a cleaning step of cleaning the inside of the water tank after the sterilization step; and a water discharge step of discharging the water in the water tank.

2. The washing machine as claimed in claim 1,

the control unit controls the heating unit based on an output of a temperature detection unit for detecting the temperature of the water tank in the sterilization step, and heats the upper portion of the water tank to a predetermined temperature.

3. A washing machine according to claim 2,

the control unit maintains the predetermined temperature for a predetermined time.

4. A washing machine according to any one of claims 1 to 3,

the controller agitates the heated water stored in the water tank by the rotational driving of the washing tank in the sterilization step.

5. A washing machine according to any one of claims 1 to 4,

the washing machine further has:

a circulating water passage provided to guide the water in the water tank from a bottom of the water tank into the washing tank; and

a pump for circulating the water in the water tank through the circulating water passage,

the control unit drives the pump during the tank cleaning operation to circulate the water in the water tank through the circulation water passage.