Drum type washing machine

Abstract

To suppress noise caused by collision between an outer tub and a housing and to suppress finishing without dewatering being completed, by reducing a small load and unbalance of single piece of clothing when a drum and the outer tub are expanded.SOLUTION: In a state where a drum 21 is increased to rotational frequency at which clothing sticks and the rotational frequency of the drum 21 is maintained for predetermined time, a drum type washing machine 100 acquires rotational fluctuation by acquisition means for rotational fluctuation of the drum, and in the case where the rotational fluctuation is smaller than a determination threshold value of unbalance and larger than a correction determination threshold value of unbalance, the rotational frequency of the drum 21 is lowered stepwise, and every time the rotational frequency of the drum 21 is lowered, in a state where the rotational frequency of the drum 21 is maintained for predetermined time, by the acquisition means for rotational fluctuation of the drum 21, the rotational fluctuation is acquired, and, when comparing the rotational fluctuation with the correction determination threshold value of unbalance, in the case where the rotational fluctuation is small, the rotational frequency of the drum 21 is increased higher than the rotational frequency at which the clothing sticks.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a drum-type washing machine that spins a drum at high speed to dehydrate wet clothes after washing. In this specification, the drum-type washing machine includes a drum-type washer-dryer that performs drying in addition to washing and spin-drying. [Background technology]

[0002] During the spin cycle of a drum-type washing machine, uneven distribution of clothes (hereinafter referred to as "imbalance") creates a vibrating force, increasing vibration of the washing tub (hereinafter referred to as the "outer tub"). If the imbalance is large, the vibration of the outer tub becomes excessive during the spin cycle, so the spin cycle is repeated (hereinafter referred to as a "retry") to reduce the imbalance and continue spin cycle. The retry rotates the drum at a slower speed to reduce tangling of clothes, thereby reducing the imbalance and vibration of the outer tub. Imbalance is likely to increase with small loads or single clothes that do not stick evenly to the drum. Patent Document 1 is a document related to reducing imbalance for small loads or single clothes. Patent Document 1 describes that when the normal spin cycle is performed a predetermined number of times through a retry process (hereinafter referred to as a "retry"), the spin cycle is performed with rotation control that extends the time in the low rotation speed range R1 compared to the normal spin cycle. Furthermore, in Patent Document 1, the low rotation speed range R1 is set to a range in which the centrifugal force acting on the laundry in the rotating tub (referred to as the "drum" in this specification) due to the rotation of the rotating tub becomes smaller than the gravity acting on the laundry, that is, a range of rotation speeds before the laundry sticks to the inner peripheral wall of the rotating tub. Specifically, it is described that the low rotation speed range is set to a rotation speed of the rotating tub of 30 rpm or more and 40 rpm or less.

[0003] Patent Document 2 also provides literature on the drum acceleration rate during the spin cycle for small loads and single loads of laundry. Patent Document 2 states that when the amount of laundry to be washed (load) is small, less water is used during the washing and rinsing processes than when the amount of laundry (load) is large. Therefore, the spin cycle begins when the amount of water remaining in the outer tub is small. Furthermore, when the amount of laundry is small, less water is extracted from the laundry during spin cycle than when the amount of laundry is large. It also states that when the amount of laundry is small, the acceleration rate is increased in each section (outer tub resonance section, housing resonance section, and housing post-resonance section). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-120 [Patent Document 2] Japanese Patent Publication No. 2020-81417 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, there has been an increasing need to wash large amounts of clothes at one time, leading to an increase in washing capacity (hereinafter referred to as "large capacity"). To increase capacity, it is necessary to enlarge the drum into which the clothes are put and the outer tub that contains the drum. On the other hand, if the width of the drum-type washing machine is also increased to enlarge the drum and outer tub, the drum-type washing machine will become larger, making it difficult to transport and install. Therefore, it is necessary to increase the capacity while maintaining the width of the drum-type washing machine.

[0006] If the outer tub is enlarged while maintaining the width of the drum-type washing machine's main body, the gap between the outer tub and the housing that constitutes the drum-type washing machine's main body will decrease, making it more likely for the outer tub to come into contact with the housing and resulting in abnormal noise. Furthermore, as mentioned above, imbalance creates a vibrational force during spinning, and the greater the imbalance, the more likely the outer tub will vibrate excessively. If the vibration of the outer tub becomes excessive, in addition to abnormal noise, the spin cycle will be stopped midway to prevent abnormal vibrations, which could result in the spin cycle not being completed. In particular, small loads or single loads of clothing with a small laundry volume tend to be biased and stick to the drum, resulting in significant imbalance. Therefore, when spinning with clothing that is prone to imbalance, such as small loads or single loads of clothing, the outer tub is likely to vibrate excessively, potentially resulting in abnormal noise and an incomplete spin cycle.

[0007] In the retry operation of the washing machine disclosed in Patent Document 1, the time spent in the low-speed rotation range is extended compared to the normal spin cycle, correcting imbalance, and then the drum rotation speed is increased after the low-speed rotation range to adhere the clothes to the drum and perform spin drying. With this configuration, when correcting imbalance for a small load or a single load of clothes, the drum rotation speed is increased after the low-speed rotation range. Therefore, even if the imbalance is corrected in the low-speed rotation range where clothes do not adhere, the increased drum rotation speed causes the clothes to move as they adhere to the drum, resulting in a change in the balance of the clothes. As a result, when clothes adhere to the drum, significant imbalance occurs, causing excessive vibration of the outer tub, which can lead to noise and incomplete spin drying. Furthermore, the washing machine disclosed in Patent Document 2 increases the acceleration rate of the drum rotation speed when the load of clothes is small. When spinning a small load or a single load of clothes with this configuration, the water volume is small, so the water accumulated in the outer tub is discharged outside the machine, but the detergent foam is not completely discharged, leaving foam remaining in the drum and outer tub. If spin-drying is performed while foam remains in the drum or outer tub, the foam will act as a load to rotate the drum, causing the motor current value to exceed a specified value, which could cause spin-drying to stop midway and prevent it from being completed.

[0008] To provide a drum-type washing machine that suppresses abnormal noises caused by the outer tub colliding with the housing when the drum and outer tub are expanded during spin-drying of a small load or a single piece of laundry, and that prevents spin-drying from ending prematurely. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention provides a drum-type washing machine comprising a rotatable drum whose rotation axis is horizontal or tilted so that the rear side is downwards, an outer tub that contains the drum and stores wash water, a housing that contains the outer tub, a means for acquiring rotational fluctuations of the drum, and an imbalance determination means that determines imbalance of laundry in the drum, wherein the drum rotation speed is increased to a speed at which clothes stick, and the drum rotation speed is maintained for a predetermined time while the drum rotation speed is acquired by the drum rotation fluctuation acquisition means, and if the rotation fluctuation is smaller than the imbalance determination threshold and larger than the imbalance correction determination threshold, the drum rotation speed is reduced in stages, and each time the drum rotation speed is reduced, the drum rotation speed is maintained for a predetermined time while the drum rotation speed is acquired by the drum rotation fluctuation acquisition means, and if the rotation fluctuation is smaller than the imbalance correction determination threshold, the drum rotation speed is increased to a speed higher than the drum rotation speed at which clothes stick. Other means will be described later. [Effects of the Invention]

[0010] According to the present invention, a drum-type washing machine can be provided that suppresses abnormal noises caused by the outer tub colliding with the housing when the drum and outer tub are expanded during spin-drying with a small load or a single piece of clothing, and that prevents the spin-drying process from ending prematurely. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view of a drum-type washing machine according to an embodiment of the present invention; [Figure 2]2 is a cross-sectional view of the internal structure of the drum-type washing machine of FIG. 1, as viewed from the right side. [Figure 3A] FIG. 1 is a diagram (1) showing the drum rotation operation in the dehydration process of the present invention. [Figure 3B] FIG. 2 is a diagram (2) showing the drum rotation operation in the dehydration process of the present invention. [Figure 4] 4 is a flowchart showing the operation of a spin-drying process according to one embodiment of the present invention. [Figure 5A] 1 is a flowchart (1) showing the operation of a spin-drying process according to an embodiment of the present invention. [Figure 5B] 10 is a flowchart (2) showing the operation of the spin-drying process according to one embodiment of the present invention. [Figure 6] 10A and 10B are diagrams illustrating the drum rotation operation for correcting imbalance in the spin-drying process according to one embodiment of the present invention. [Figure 7A] 1A and 1B are diagrams (1) and (2) showing drum rotation operations in washing according to two embodiments of the present invention. [Figure 7B] FIG. 10 is a diagram (2) showing the drum rotation operation in washing according to the second embodiment of the present invention. [Figure 8] FIG. 10 is a flow chart showing a dehydration process according to two embodiments of the present invention. [Figure 9A] 1A and 1B are diagrams showing the drum rotation operation in the dehydration process according to two embodiments of the present invention; [Figure 9B] FIG. 10 is a diagram (2) showing the drum rotation operation in the dehydration process according to the second embodiment of the present invention. [Figure 10A] 1A and 1B are diagrams showing drum rotation and water injection timing in washing according to two embodiments of the present invention; [Figure 10B] FIG. 10 is a diagram (2) showing the drum rotation operation and water injection timing in washing according to the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of a drum-type washing machine according to the present invention will be described with reference to the drawings. Note that each drawing is merely a schematic illustration to allow a sufficient understanding of the present invention. Therefore, the present invention is not limited to the illustrated examples. Furthermore, in each drawing, common or similar components are denoted by the same reference numerals, and redundant explanations thereof will be omitted. Furthermore, the drum-type washing machine according to the present invention also includes a drum-type washer-dryer equipped with a drying function.

[0013] [Example 1] First, a drum type washing machine 100 according to a first embodiment of the present invention will be described with reference to FIGS.

[0014] Fig. 1 is a perspective view of a drum type washing machine 100 of this embodiment. Fig. 2 is a cross-sectional view of the internal structure of the drum type washing machine 100 of this embodiment as seen from the right side. As shown in both figures, the outer shell of the drum type washing machine 100 is covered with a housing 1, which is made up of left and right side panels 1a, a front cover 1b, a rear cover 1c, a top cover 1d, and a bottom cover 11. The top cover 1d is provided with a water supply hose connection port 30 for supplying water to the drum type washing machine 100 from a water faucet.

[0015] Door 2 covers an opening (not shown) for putting in and taking out clothes, located approximately in the center of front cover 1b, and is supported openably and closably by a hinge (not shown) attached to front cover 1b. Door 2 opens when door opening handle 2a is pulled to release a locking mechanism (not shown), and closes when pressed against front cover 1b, locking the locking mechanism. Front cover 1b has a circular opening 1ba for putting in and taking out clothes, approximately concentric with opening 9a in front stay 9 and opening 17a in outer tub 17.

[0016] An operation / display panel 3 provided on the top of the housing 1 includes a power switch 4 and an operation switch 5. The operation / display panel 3 is electrically connected to a control device 13 provided inside the housing 1.

[0017] An outer tub 17 for storing water is provided inside the housing 1. The lower part of the outer tub 17 is supported by dampers 29 fixed to the housing 1. The dampers 29 consist of four parts: a front first damper 25, a front second damper 26, a rear first damper 27, and a rear second damper 28. The upper part of the outer tub 17 is connected to the upper stay 7 by a suspension device 12, so that the outer tub 17 is supported in a suspended state on the housing 1. The suspension device 12 is formed of, for example, a coil spring.

[0018] A weight 40 is provided at the front lower part of the outer tub 17, a weight 41 is provided at the front upper part of the outer tub 17, and a weight 42 is provided at the back of the outer tub 17.

[0019] The outer tub 17 contains a drum 21 for storing clothes. A motor 22 for rotating the drum 21 is disposed behind the outer tub 17. The motor 22 has a shaft 22a, which serves as a rotation axis, passing through the outer tub 17 and connecting to the drum 21. The motor 22 also has a Hall element for detecting the motor rotation speed, and outputs the motor rotation speed detected by the Hall element to the control device 13. By expanding the drum 21 and outer tub 17 in the front-to-rear direction, the capacity is increased while maintaining the width of the housing 1.

[0020] A vibration sensor 24 for detecting vibrations of outer tub 17 is fixed to the bottom of outer tub 17. The value of vibration sensor 24 is output to control device 13. Control device 13 is a component that functions as an imbalance determination means for determining imbalance of laundry in the drum.

[0021] The control device 13 appropriately controls the opening and closing of the water supply valve 31, the opening and closing of the drain valve 34a, the rotation of the motor 22, the heat generation of the heater (not shown), and the like, in response to commands input by the user via the operation / display panel 3, detected values ​​from various sensors, control programs, and the like, to perform various processes, such as washing, rinsing, spin-drying, and drying. Of these processes, the spin-drying process according to the present invention will be described in detail below. Based on the motor rotation speed input from the motor 22, the control device 13 calculates the rotation fluctuation from the rotation speed of the drum 21 corresponding to that motor rotation speed and the maximum and minimum values ​​of the rotation speed of the drum 21 during one rotation of the drum 21. The rotation speed of the drum 21 during one rotation is minimum when the clothes are rotated from top to bottom and maximum when the clothes are rotated from bottom to top. The greater the imbalance, the slower the rotation speed of the drum 21 when the clothes are rotated from bottom to top and the faster the rotation speed of the drum 21 when the clothes are rotated from top to bottom. Therefore, the greater the imbalance, the greater the difference between the maximum and minimum rotational speeds of the drum 21 during one rotation, and therefore the greater the rotational fluctuations. In addition, the control device 13 calculates the outer tub vibration value in any direction based on the vibration value input from the vibration sensor 24.

[0022] When motor 22 is driven, drum 21 is driven to rotate in both forward (clockwise when viewed from the front of drum type washing machine 100) and reverse (counterclockwise when viewed from the front of drum type washing machine 100). Rotation axis Az of drum 21 is horizontal from the front to the rear of drum type washing machine 100 or is inclined so that the back side is downwards. Figure 2 shows a state in which it is inclined so that the back side is downwards.

[0023] Drum 21 is provided with a plurality of dewatering holes 21b for draining the wash water in drum 21 into outer tub 17, and is provided with a plurality of baffles 23 (only one is shown in FIG. 2) on its inner circumferential surface. The baffles 23 are spaced apart around the circumferential direction of drum 21 and lift up clothes placed in drum 21 as drum 21 rotates. Baffles 23 extend in the front-to-rear direction of drum 21.

[0024] A cylindrical fluid balancer 21c is provided at the front end (front surface) of the drum 21. The outer tub 17 is a generally cylindrical structure with an open front and a closed rear, and a bottom. The opening of the outer tub 17 and the loading port of the housing 1 are connected by a bellows 19 that easily expands and contracts in the front-to-rear direction. The bellows 19 is made of an annular elastic member, and seals the drum 21 with water when the door 2 is closed. The loading port of the housing 1, the opening of the outer tub 17, and the opening of the drum 21 are all connected, and opening the door 2 allows clothes to be put into or taken out of the drum 21. The outer tub 17 can be divided into a side including the opening and a side to which the motor 22 is attached.

[0025] A water supply valve 31 is disposed below the water supply hose connection port 30. One end of a water supply hose 32 for supplying water to the outer tub 17 is connected to the water supply valve 31. When the water supply valve 31 is opened, water flows from the water supply hose connection port 30 through the water supply hose 32 into the detergent container 33, and is supplied into the outer tub 17 from the front water supply hose 35 or the rear water supply hose 36.

[0026] A drain valve 34a is provided in the drain path of a drain hose 34 provided at the bottom of outer tub 17. When drain valve 34a is closed, the water supplied to outer tub 17 accumulates in outer tub 17, and when drain valve 34a is opened, the wash water in outer tub 17 is drained from drain hose 34 to the outside of drum-type washing machine 100.

[0027] <Basic operation of the drum-type washing machine 100> Next, the basic operation of the drum type washing machine 100 will be described with reference to Figures 3A and 3B. Figures 3A and 3B are diagrams each showing the rotational operation of the drum 21 during the spin cycle. In the drum type washing machine 100, the user first presses the power switch 4 to start the drum type washing machine 100. Then, the user pulls the door open handle 2a to open the door 2 and place clothes into the drum 21, then closes the door 2, and operates the operation switch 5 to set up operation and start operation.

[0028] When operation begins, the drum 21 rotates under the control of the control device 13, and the laundry volume before water is poured is calculated. The laundry volume is calculated based on the current value of the motor 22 when it is rotated. At this time, the larger the laundry volume, the greater the load on the motor 22 and the larger the current value, so the laundry volume can be determined from the current value. Then, the amount of detergent to be dispensed is displayed on the operation and display panel 3 based on the laundry volume. At this time, the larger the calculated laundry volume, the larger the amount of detergent to be dispensed. The user checks the display on the operation and display panel 3 and dispenses a predetermined amount of detergent into the detergent container 33. The control device 13 then starts the washing process.

[0029] During the washing cycle, the control device 13 opens the water supply valve 31, and supplies water from the water supply hose connection port 30, along with detergent, into the outer tub 17 via the water supply hose 32, the detergent container 33, and the front water supply hose 35 or the rear water supply hose 36. The larger the calculated laundry volume, the greater the amount of water supplied during the washing cycle. After this operation is performed for a predetermined time, the washing cycle is repeated, with the drum 21 rotating forward, stopped, reversed, and stopped, for a predetermined time. During this operation, the laundry is repeatedly lifted and dropped by the baffle 23, enhancing the washing power of the laundry.

[0030] After the washing cycle, the control device 13 executes the spin-drying cycle. In the spin-drying cycle shown in FIG. 3A, the drum 21 is first rotated at a low rotation speed (e.g., less than 80 r / min) that prevents clothes from sticking to the drum 21. At the low rotation speed, clothes that have become wet during the washing cycle are lifted by the baffle 23 as the drum 21 rotates, and are spread out on the inner circumferential surface of the drum 21 as the clothes fall. Once the clothes begin to spread, the rotation speed of the drum 21 is gradually increased (e.g., to 100 r / min) to cause the clothes to stick to the drum 21 (sticking rotation speed range). Once the clothes stick to the drum 21, the rotation speed of the drum 21 is increased, passing through the resonance rotation speed range of the outer tub 17 (e.g., 100 to 400 r / min), until it reaches a steady rotation speed (e.g., 900 r / min), and the water contained in the clothes is centrifugal dehydrated. The resonant rotation speed of the outer tub 17 is a value obtained by converting the natural frequency (Hz) at which the outer tub 17 resonates into a rotation speed (rpm).

[0031] If the imbalance is large, clothes stick to the drum 21, and the rotational fluctuations in the sticking rotational speed range and the vibration of the outer tub 17 become large in the resonance rotational speed range of the outer tub 17. If the rotational fluctuations or outer tub vibration values ​​calculated by the control device 13 exceed a predetermined value (hereinafter referred to as "imbalance detection"), the rotational speed of the drum 21 shown in Figure 3B is stopped and the spin cycle is repeated (hereinafter referred to as "retry"). Furthermore, if the number of imbalance detections or retries exceeds a predetermined number, the spin cycle after the washing cycle is skipped and the process moves to the next cycle.

[0032] After the spin cycle, the control device 13 executes the rinsing cycle. In the rinsing cycle, the water supply valve 31 is opened, and water supplied from the water supply hose connection port 30 is supplied into the outer tub 17 via the water supply hose 32, the detergent container 33, and the front water supply hose 35 or the rear water supply hose 36. As with the washing cycle, the larger the calculated laundry volume, the greater the amount of water supplied. In the rinsing cycle, as with the washing cycle, the drum 21 repeatedly rotates forward, stops, reverses, and stops. During this cycle, an agitation operation is performed for a predetermined period of time, during which the clothes lifted by the baffle 23 fall.

[0033] Thereafter, the control device 13 repeats the spin-drying and rinsing steps a predetermined number of times, and then moves on to the final spin-drying step. If the number of imbalance detections or retries exceeds a predetermined number during the spin-drying step after the rinsing step, the control device 13 skips the spin-drying step after the rinsing step and moves on to the next step. If the number of imbalance detections or retries exceeds a predetermined number during the final spin-drying step, an error is reported.

[0034] If the drum-type washing machine has a drying function, the control device 13 executes a drying process after the final spin-drying process. The rotation speed of the drum 21 during the drying process is set to be slower than that during the washing process. During the drying process, the drum 21 rotates at a slow speed, and a blower unit (not shown) blows warm air onto the clothes in the drum 21 to dry the clothes while reducing wrinkles in the clothes.

[0035] <Drum rotation and dehydration control in the dehydration process> Next, the rotational operation of drum 21 in the dehydration process and the dehydration control will be described in detail with reference to FIGS.

[0036] Fig. 4 is a flowchart showing the operation in the low rotation speed range and the attachment rotation speed range in the spin-drying process. Fig. 5A and Fig. 5B are flowcharts showing the operation of increasing the rotation speed of drum 21 in the spin-drying process and determining whether the spin-drying process is started, respectively.

[0037] First, the operation at the start of the spin cycle will be described with reference to Figure 4. When the spin cycle starts, a loosening operation (S201) is performed to reduce tangles in the clothes and then spin the clothes, by rotating drum 21 in the forward direction, which is the opposite rotation direction to the spin rotation direction, and then the rotation speed of drum 21 is stopped at 0 r / min (S202), and the process proceeds to step S203.

[0038] In step S203, while rotating the drum 21 in the reverse direction, the rotation speed of the drum 21 is increased (S203) to a rotation speed R0 (e.g., 75 r / min) at which the clothes stick to the drum, and the rotation speed R0 is maintained for a time t1 (S204) to calculate the rotation fluctuation. Because the clothes stick to the drum 21 due to centrifugal force, the rotation speed R0 at which the clothes stick to the drum 21 is determined in advance by testing based on the rotation speed and diameter of the drum 21.

[0039] Time t1 is the time it takes for the drum 21 to rotate one or more revolutions, and the rotation fluctuation is acquired. After calculating the rotation fluctuation in step S204, a first imbalance determination (S205) is performed in which the rotation fluctuation is compared with a first threshold value. If it is determined in step S205 that the rotation fluctuation is less than the first threshold value (S205, less than threshold value), a second imbalance determination (S206) is performed in which the rotation fluctuation is compared with a second threshold value. If it is determined in step S205 that the rotation fluctuation is equal to or greater than the first threshold value (S205, greater than threshold value), the rotation speed of the drum 21 is stopped at 0 r / min (S213).

[0040] In the second imbalance determination in step S206, if the rotational fluctuation is less than the second threshold (S206, less than threshold), the process proceeds to step S215 in Fig. 6, where the rotational speed of the drum 21 is increased. In the second imbalance determination (S206), if the rotational fluctuation is equal to or greater than the second threshold (S206, greater than or equal to threshold), the rotational speed of the drum 21 is reduced to R1 (S207), and the rotational speed of the drum 21 is maintained at R1 for time t1 (S208), and the rotational fluctuation is calculated.

[0041] The first threshold and the second threshold will now be described. The first threshold is set to a value greater than the second threshold. The first threshold is used to determine whether the clothes are unbalanced overall and whether the rotation speed of the drum 21 should be stopped at 0 r / min and a loosening operation should be performed to correct the overall balance of the clothes. The second threshold is used as an imbalance correction determination threshold, and is used to determine whether the clothes are balanced and whether the rotation speed of the drum 21 can be increased. The first threshold and the second threshold are determined in advance through testing.

[0042] In the second imbalance determination in step S206, if the rotational fluctuation is less than the second threshold (S206, less than threshold), a third imbalance determination (S209) is performed in which the rotational fluctuation at R1 of the rotational speed of the drum 21 calculated in step S208 is compared with the second threshold. If the rotational fluctuation is less than the second threshold (S209, less than threshold), the process proceeds to step S215 in FIG. 6, where the rotational speed of the drum 21 is increased. If, in the third imbalance determination (S209), the rotational fluctuation is equal to or greater than the second threshold (S209, greater than threshold), the rotational speed of the drum 21 is reduced to R2 (S210), and the rotational speed of the drum 21 is maintained at R2 for time t1 (S211), and the rotational fluctuation is calculated.

[0043] In the third imbalance determination (S209), if the rotational fluctuation is equal to or greater than the second threshold (S209, threshold or greater), a fourth imbalance determination (S212) is performed in which the rotational fluctuation at R2 of the drum 21 calculated in step S211 is compared with the second threshold. In the fourth imbalance determination (S212), if the rotational fluctuation is less than the second threshold (S212, less than threshold), the process proceeds to step S215 in FIG. 6, where the rotational speed of the drum 21 is increased. In the fourth imbalance determination (S212), if the rotational fluctuation is equal to or greater than the second threshold (S212, threshold or greater), the rotational speed of the drum 21 is stopped at 0 r / min (S213).

[0044] Next, the spin-drying operation when the rotational fluctuation is less than the second threshold value in the second imbalance determination (S206), the third imbalance determination (S210), or the fourth imbalance determination (S213) will be described with reference to FIG. 5A. When the rotational speed of the drum 21 is increased (S215), the drum 21 passes through the aforementioned resonant rotational speed range of the outer tub 17, which tends to increase vibration of the outer tub 17. To prevent abnormal noise and vibration due to a collision between the outer tub 17 and the housing 1 within the resonant rotational speed range of the outer tub 17, spin-drying is performed while determining whether the rotational speed of the drum 21 has reached the target rotational speed (S217) while judging the outer tub vibration value and the threshold value (S216). If the rotational speed of the drum 21 reaches the target rotational speed (S217, reached) in step S217, the target rotational speed is maintained for a predetermined time (S218), and the spin-drying process is terminated. If the rotation speed of the drum 21 has not reached the target rotation speed (S217, not reached), the rotation speed of the drum 21 is increased (S215) and the outer tub vibration value is compared with a threshold value (S216) until the rotation speed of the drum 21 reaches the target rotation speed.

[0045] Here, the spin-drying operation when the threshold value is exceeded in steps S205, S212 of FIG. 4 and step S216 of FIG. 5A will be described. If the threshold value is exceeded in steps S205, S212, or S216, the rotation speed of drum 21 is stopped at 0 r / min (S213). Then, it is determined whether the number of retries has reached a predetermined number (S214). If the number of retries is less than the predetermined number in step S214 (S214, less than the predetermined number), the process proceeds to step S201 and a retry is performed. If the number of retries has reached the predetermined number in step S214 (S214, reached the predetermined number), the process proceeds to step S219 of FIG. 5B. In step S219, a spin-drying process is determined. If the spin-drying process is other than the final spin-drying process in step S219 (S219, other than the final spin-drying process), the spin-drying process is skipped (S220) and the process proceeds to the next process. In step S219, if the spin-drying process is the final spin-drying process (S219, final spin-drying process), a spin-drying error is reported (S220) and operation is terminated. In this embodiment, if the number of retries for the final spin-drying process reaches a predetermined value, a spin-drying error is reported (S221), but an additional spin-drying process (hereinafter referred to as a "return cycle") may be performed after the final spin-drying process.

[0046] <Drum rotation to correct imbalances in the spin-drying process> Next, a method for correcting imbalance during the spin cycle in this embodiment will be described using Figures 4 and 6. Figure 6 shows a schematic diagram of the movement of clothes when correcting imbalance. Imbalance occurs when clothes overlap inside the drum 21, and clothes that stick to the outer periphery of the drum 21 are stuck in a balanced manner. Note that this embodiment describes a method for correcting imbalance when a small load or a single piece of clothing is used, which tend to cause large imbalances.

[0047] In step S206, if the rotation fluctuation is equal to or greater than the second threshold, the rotation speed of the drum 21 is reduced from R0, at which the clothes stick to the drum 21, to R1. The rotation speed R1 of the drum 21 is set to a rotation speed (e.g., 70 r / min) at which the clothes do not all fall off the drum 21.

[0048] At a rotation speed R0 at which clothes stick to the drum 21, unbalanced clothes remain stuck to the drum 21 even when the drum 21 is rotated from top to bottom or from top to bottom. Because clothes stick due to the centrifugal force of the drum 21, when the rotation speed of the drum 21 is reduced from R0, the speed at which clothes stick to the drum 21, to R1, clothes stuck to the outer periphery, which has a larger radius of rotation from the center of rotation of the drum 21, remain stuck to the drum 21, while unbalanced clothes on the inner side, which has a smaller radius of rotation from the center of rotation, fall off. By reducing the rotation speed R0 at which clothes stick to the drum 21 to R1, clothes that are stuck to the outer periphery of the drum 21 in a balanced manner remain stuck to the drum 21, and only the unbalanced clothes can be moved. Therefore, by reducing the rotation speed of the drum 21 from R0 to R1, only the unbalanced clothes can be moved, correcting the imbalance. In this state, the rotational fluctuation is calculated in step S208, and if the rotational fluctuation is less than the second threshold value in the third imbalance determination (S209) (S209, less than threshold value), the rotational speed of the drum 21 can be increased while most of the clothes are still stuck to the drum 21. If the rotational speed at which clothes stick to the drum 21 is different from the rotational speed at which the clothes are loosened, as in Patent Document 1, the imbalance state may change while the rotational speed of the drum 21 is increased to the rotational speed at which the clothes stick to the drum 21, and the imbalance may become greater. On the other hand, in the imbalance correction of this embodiment, the imbalance can be corrected while most of the clothes are still stuck to the drum 21, and the rotational speed of the drum 21 can be increased to the rotational speed at which the clothes stick to the drum 21 while maintaining a small imbalance.

[0049] Depending on the degree of overlap of the clothes, there is a concern that the imbalance may not be corrected at the rotation speed R1 of the drum 21. Therefore, in step S209, if the rotation fluctuation is equal to or greater than the second threshold, the rotation speed of the drum 21 is gradually reduced from R1 to R2. This allows the clothes that have become unbalanced inside the drum 21 to fall further from the drum 21 while maintaining the clothes stuck to the outer periphery of the drum 21. As described above, the rotation speed of the drum 21 can be increased with the imbalance corrected. The rotation speed R2 of the drum 21 is set to a rotation speed (e.g., 65 r / min) at which all of the clothes do not fall from the drum 21.

[0050] As described above, when a small load or a single garment is used, which tend to cause large imbalances, correcting the imbalance allows the rotation speed of the drum 21 to be increased while the imbalance is small, thereby preventing excessive vibration of the outer tub 17 and suppressing the generation of abnormal noise due to a collision between the outer tub 17 and the housing 1 and premature termination of the spin cycle. Note that in this embodiment, the rotation speed of the drum 21 is reduced in two stages, from R0 to R1 and R2, to correct the imbalance, but the rotation speed of the drum 21 may be reduced in more than two stages.

[0051] [Example 2] Next, a second embodiment will be described with reference to Figures 7A to 10B. In the second embodiment, when the number of retries exceeds a predetermined number for a light load or a single laundry, and the spin-drying process is skipped, the spin-drying control is changed from normal spin-drying control to spin-drying control for a light load or a single laundry. Note that the drum-type washing machine 100 has a configuration basically similar to that of the first embodiment, and therefore, only the differences will be described below.

[0052] First, the control of the spin cycle in Example 2 will be described with reference to FIGS. 7A, 7B, and 8. FIGS. 7A and 7B are schematic diagrams showing the rotational movement of the drum 21 during a washing operation. FIG. 7A schematically shows the rotational movement of the drum 21 when the washing operation is completed without skipping during the spin cycle. The washing operation involves three spin cycles: rinse-spin 1, rinse-spin 2, and final spin cycle. If no skip occurs during each spin cycle, spin cycles are performed using normal spin cycle control even for a small load or a single laundry. FIG. 7B schematically shows the rotational movement of the drum 21 during a washing operation when a skip occurs during rinse-spin 1. If a skip occurs during rinse-spin 1, an additional spin cycle (additional spin cycle) is performed after rinse-spin 2, followed by a final spin cycle. During rinse-spin 1, spin cycles are performed using normal spin cycle control even for a small load or a single laundry. If a skip occurs in rinse spin 1, the subsequent spin cycle will be performed using spin control for small loads or single clothes to prevent skips. Note that Figure 7B shows an example of spin control when a skip occurs in rinse spin 1, but if rinse spin 1 completes without a skip and a skip occurs in rinse spin 2, rinse spin 2 will be performed using normal spin control, and small load or single clothes spin control will be used in the spin cycles of the additional spin and final spin.

[0053] FIG. 8 shows the application flow of spin control for a small load or a single garment. When operation starts, the laundry volume is determined based on the current value (S301), as described in the first embodiment. If the determined laundry volume is not a small load or a single garment (S301, not a small load or a single garment), normal spin control (S321) is performed, with rinse spin 1 (S322), rinse spin 2 (S323), and final spin (S324). Note that the processes in steps S321 to S324 are the same as those in steps S302, S303, S308, and S314, respectively, described below. If the laundry volume is determined to be a small load or a single garment (S301, small load or a single garment), normal spin control (S302) is performed with rinse spin 1 (S303).

[0054] After rinse spin 1 (S303), skip determination 1 (S304) in rinse spin 1 (S303) is performed. If spin is completed without skipping in rinse spin 1 (S303), skip determination 1 (S304, no skip) is made, and rinse spin 2 (S308) of step S308 is performed using normal spin control. If the number of retries reaches a predetermined number in rinse spin 1 (S303) and a skip is made, skip determination 1 (S304, skip) determines that a skip is made, and a small load and single garment determination (S305) is made. If a small load is determined in the small load and single garment determination (S305, small load), small load spin control is applied to perform the subsequent spin process. If a small load and single garment is determined to be a single garment (S305, single garment), single garment spin control is applied to perform the subsequent spin process. In steps S301, S310, and S315, which determine whether the load is small or whether the clothing is a single garment, reference is made to the result of determining the clothing capacity based on the current value (S301).

[0055] Here, spin control for small loads and spin control for single clothes will be described. The spin control for small loads is spin control applied to small loads where clothes do not stick to the drum 21 in a balanced manner, while the spin control for single clothes is spin control applied to clothes washed on a single mat, etc. A small load does not stick to the drum 21 in a balanced manner and is prone to greater imbalance. However, a single piece of clothing tends to stick to a part of the drum 21, making it more prone to greater imbalance than a small load. Therefore, the spin control for single clothes sets the outer tub vibration value and rotation fluctuation thresholds higher than those for small loads to make it easier to complete the spin. In this embodiment, the spin control for small loads and spin control for single clothes have different thresholds for the outer tub vibration value and rotation fluctuation. However, since both types of clothes tend to be more unbalanced, the same thresholds may also be applied. The spin control for small loads or single clothes and the normal spin control will be described later.

[0056] If the spin cycle is completed without skipping in rinse spin 2 (S308) and also without skipping in rinse spin 1 (S303), skip determination 2 (S309, no skip in rinse spin 1 and rinse spin 2) determines that no skip was performed, and the final spin cycle is performed using normal spin control in step S314. If the number of retries in rinse spin 2 (S308) reaches the predetermined number and a skip is performed, or if skip determination 1 determines that a skip is performed (S304, skip is performed), skip determination 2 (S309, skip is performed in rinse spin 1 or rinse spin 2) determines that a skip is performed, and a determination is made between a small load and a single garment (S310). If the determination between a small load and a single garment determines that a small load is performed (S310, small load), small load spin control is applied (S311), and the subsequent spin cycles are performed. If the determination of a small load and a single garment determines that the garment is a single garment (S310, single garment), spin control for a single garment is applied (S312) and the subsequent spin process is carried out.

[0057] If a skip occurs in either or both of rinse spin 1 (S303) and rinse spin 2 (S308), the rotation speed of the drum 21 does not increase and the spin cycle ends, which may result in insufficient rinsing, so additional spin (S313) is performed. When additional spin (S313) is performed with a small load or a single load of laundry, spin is performed with control for a small load or a single load of laundry applied, and the process proceeds to the final spin of step S314.

[0058] If the spin cycle is completed without skipping in the final spin cycle (S314), skip determination 3 (S315, no skip in final spin cycle) determines that no skipping has occurred, and the operation is terminated. If the number of retries reaches a predetermined number and a skip is performed in the final spin cycle (S314), skip determination 3 (S315, skip in final spin cycle) determines that a skip has occurred, and a determination is made as to whether the load is small or whether the laundry is a single garment (S316). If the determination as to whether the load is small or whether the laundry is a single garment (S316, small load), spin control for small loads is applied (S317). If the determination as to whether the load is small or whether the laundry is a single garment (S316, single garment), spin control for single garments is applied (S318), and the operation proceeds to the return cycle in step S319. The return cycle (S319) is an additional spin cycle when the final spin cycle (S314) is skipped, and the operation is terminated after the return cycle (S319) is completed.

[0059] <Spin control for small loads or single garments> Next, spin control for a small load or a single load of clothing will be described using FIGS. 9A, 9B, and 10. FIGS. 9A and 9B are diagrams illustrating the rotational motion of the drum 21 during the spin cycle. FIG. 9A illustrates an example of the rotational motion of the drum 21 during the spin cycle for normal spin control and for a small load or a single load of clothing. The spin control for a small load or a single load of clothing has a higher acceleration rate of the rotational speed of the drum 21 in the resonant rotational speed range of the outer tub 17 than the normal spin control. FIG. 9B illustrates the vibration of the outer tub 17 when the rotational motion of the drum 21 illustrated in FIG. 9A is applied. Since a small load or a single load of clothing tends to be distributed toward the rear of the drum 21 and tends to become unbalanced behind the drum 21, FIG. 9B illustrates the results of simulating the imbalance of a small load or a single load of clothing by placing a weight behind the drum 21. Clothing that tends to become unbalanced behind the drum 21, such as a small load or a single load of clothing, experiences greater vibration at the rear of the outer tub 17 than at the front of the outer tub 17. When the vibration at the rear side of the outer tub 17 becomes large, the effect on the flow of the liquid (vibration effect on the outer tub 17) sealed in the fluid balancer 21c provided at the front end of the drum 21 becomes small. Therefore, by increasing the acceleration rate of the rotation speed of the drum 21 in the resonant rotation speed range of the outer tub 17, the resonance of the outer tub 17 can be overcome before the vibration of the outer tub 17 is amplified in the resonant rotation speed range of the outer tub 17, and therefore the vibration of the outer tub 17 can be reduced.

[0060] When the laundry volume is larger than a small load or a single load, the clothes are distributed also at the front of the drum 21, which can easily cause imbalance at the front of the drum 21. When imbalance occurs at the front of the drum 21, the vibration at the front of the outer tub 17 becomes greater than that at the rear of the outer tub 17. When the vibration at the front of the outer tub 17 becomes greater, it impedes the flow of liquid sealed in the fluid balancer 21c provided at the front end of the drum 21. Therefore, if the acceleration rate of the drum 21 is increased, the flow of liquid sealed in the fluid balancer 21c may deteriorate, which may increase the vibration of the outer tub 17.

[0061] Therefore, the spin control for small loads or single clothes can reduce the vibration of the outer tub 17 by increasing the acceleration rate of the rotation speed of the drum 21 in the resonant rotation speed range of the outer tub 17 compared to normal spin control, so that the threshold values ​​for the outer tub vibration value and rotation fluctuation can be made larger than those in normal spin control, and skips and premature termination of operation can be prevented in small loads and single clothes, which are prone to large imbalances.

[0062] Here, the spin control for small loads or single clothes is applied after the rinse spin 2 is determined to be skipped in the spin cycle. Therefore, the rinsing cycle immediately before that allows the foam remaining in the drum 21 to be expelled outside the machine, and when the acceleration rate of the drum 21 is increased, the foam can be prevented from becoming a burden on the increase in the rotation speed of the drum 21, preventing the spin cycle from stopping midway.

[0063] 10A and 10B are diagrams showing the rotational movement of the drum 21 and the timing of water injection during washing, respectively. FIGS. 10A and 10B show the rotation speed of the drum 21 and a schematic diagram of water injection into the drum 21 during the spin cycle under normal spin control and light-load or single-laundry spin control. Under normal spin control, water injection (ON) is performed from the start of the spin cycle until the clothes stick to the drum 21. By injecting water into the drum 21, tangled clothes and detergent bubbles adhering to the door are washed away. Under light-load or single-laundry spin control, water injection is turned OFF from the start of the spin cycle until the clothes stick to the drum 21. By turning off water injection from the start of the spin cycle until the clothes stick to the drum 21, imbalance caused by water splashing onto the clothes during the spin cycle is prevented. When the rotation speed is increased to a level at which the clothes stick to the drum 21 or during a retry, imbalance caused by water being removed from the clothes can be reduced more effectively, preventing skipping or premature termination of the spin cycle.

[0064] Furthermore, small amounts of detergent are used for small loads and single laundry, and spin control for small loads or single laundry is applied from rinse spin 2 onwards, so detergent foam is discharged from drum 21 during the rinsing process after rinse spin 1. Therefore, when spin control for small loads or single laundry is applied, foam adhesion to the door can be suppressed even if water injection at the start of the spin process is turned off.

[0065] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of the embodiments with other configurations, and it is also possible to add other configurations to the configuration of the embodiments. Furthermore, it is possible to add, delete, or replace part of each configuration with other configurations. [Explanation of symbols]

[0066] 1... housing, 13... control device (unbalance determination means), 17... outer tub, 21... drum, 22... motor, 24... vibration sensor, 100... drum type washing machine

Claims

1. A drum-type washing machine includes a rotatable drum whose rotation axis is horizontal or tilted so that the rear side is downwards, an outer tub that contains the drum and stores wash water, a housing that contains the outer tub, means for acquiring rotation fluctuations of the drum, and means for determining imbalance of laundry in the drum, The rotation speed of the drum is increased to a speed at which clothes stick to the drum, and while the drum rotation speed is maintained for a predetermined time, the rotation fluctuation is acquired by the drum rotation fluctuation acquisition means, and the rotation fluctuation is judged by the imbalance judgment means. If the rotation fluctuation is smaller than the imbalance judgment threshold and larger than the imbalance correction judgment threshold, the drum rotation speed is gradually reduced, and each time the drum rotation speed is reduced, the drum rotation speed is maintained for a predetermined time, and the rotation fluctuation is acquired by the drum rotation fluctuation acquisition means, and the rotation fluctuation is compared with the imbalance correction judgment threshold. If the rotation fluctuation is small, the drum rotation speed is increased to a speed higher than the rotation speed at which clothes stick to the drum. A drum type washing machine characterized by the above.

2. A drum-type washing machine comprising: a rotatable drum whose rotation axis is horizontal or tilted so that the rear side is downwards; an outer tub that contains the drum and stores wash water; a housing that contains the outer tub; a means for determining the volume of clothes placed in the drum; a means for acquiring rotation fluctuations of the drum; a means for acquiring rotation fluctuations of the drum; a vibration acquiring means for the outer tub; a laundry imbalance determination threshold value in the drum; and a vibration determination threshold value for the outer tub, The laundry volume determining means determines whether the load is small or whether the laundry is single, and when the number of times that dehydration is repeated exceeds a predetermined number during the dehydration process, causing the dehydration process to be skipped, dehydration control for small loads or single laundry is applied to the subsequent dehydration processes. A drum type washing machine characterized by the above.

3. The drum type washing machine according to claim 2, The spin control for small loads or single clothes is performed by changing the imbalance determination threshold, the outer tub vibration determination threshold, the drum acceleration rate, and the water injection control during the spin process from the normal spin control. A drum type washing machine characterized by the above.

4. The drum type washing machine according to claim 3, In the spin control for a small load or a single piece of clothing, the imbalance determination threshold and the outer tub vibration determination threshold are set to values ​​greater than those in the normal spin control, the drum acceleration rate is set to be higher than that in the normal spin control, and water injection is turned off at the start of the spin cycle. A drum type washing machine characterized by the above.

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