Washing machines capable of spin-drying

Abstract

To effectively correct imbalances using a water-filled liquid balancer. [Solution] A washing machine 1 capable of performing a spin-drying process. It is equipped with an unbalance correction means 6 that corrects the unbalance of the drum 4 caused by the state of the laundry load. The unbalance correction means 6 has an annular trough 60 attached to the periphery of the drum 4 and a water injection unit 61 that injects water into it. When the spin-drying process is performed, the controller 20 operates the water injection unit 61 and adjusts the water injection state into the annular trough 60 according to the rotation speed of the rotating drum 4. In this way, the unbalance of the drum 4 is corrected.

Description

Technical Field

[0006] ,

[0007] ,

[0001] The disclosed technology relates to a washing machine capable of performing dehydration processing.

Background Art

[0002] The types and materials of laundry such as clothes are diverse. Therefore, their self-weights and water absorption amounts during washing are different. And inside the rotating drum, the positions of those laundry items change. Therefore, in the rotating drum, a deviation of the center of gravity different for each washing occurs (so-called imbalance).

[0003] Imbalance causes abnormal vibration in the dehydration process where the drum rotates at high speed. Therefore, conventionally, in washing machines, various countermeasures have been taken against imbalance from the viewpoints of preventing contact damage due to abnormal vibration, reducing vibration noise, and shortening the dehydration time by stable high-speed rotation.

[0004] For example, the tub of a washing machine is suspended by a support spring and elastically supported by a damper in order to impart vibration damping properties. And a high-weight weight is attached to the tub. In addition to improving the performance of these vibration damping members, various countermeasures against imbalance have also been taken for their arrangements.

[0005] Also, attaching a predetermined balancer to the drum has also been done. For example, there are a ring-shaped ball balancer that houses a plurality of hard balls inside, a liquid balancer that encloses a liquid instead of hard balls, and the like. By canceling out the center of gravity of the drum biased by the laundry with the center of gravity of the balancer, the imbalance can be corrected.

[0006] Furthermore, a liquid balancer that can adjust the weight by injecting liquid according to the state of imbalance instead of enclosing the liquid has also been proposed (Patent Document 1).

[0007] The technology described in Patent Document 1 pertains to drum-type washing machines. Drum-type washing machines have lifters (baffles) attached to multiple locations on the inner surface of the drum to lift the laundry. The technology described in Patent Document 1 utilizes these lifters.

[0008] Specifically, a predetermined ring-shaped unit (water receiving ring unit) is installed between the tub and the back of the drum. Water is then poured into each lifter through this water receiving ring unit. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2016-197 [Overview of the project] [Problems that the invention aims to solve]

[0010] In the technology described in Patent Document 1, it is necessary to create space behind the drum inside the tub and install a water receiving ring unit there. Moreover, the number of water receiving paths increases with the number of lifters. A certain amount of water is required to correct the imbalance, and the size of the water receiving ring unit must also be large. Consequently, the internal volume of the drum becomes smaller in the technology described in Patent Document 1. The amount of laundry that can be processed in one wash becomes smaller.

[0011] Furthermore, the unbalanced center of gravity can be located around the entire circumference of the drum. In contrast, the lifters are only located at a limited number of specific points around the drum (three equally spaced points in Patent Document 1). Therefore, it is difficult to properly correct the unbalance by supplying water to these lifters.

[0012] Therefore, this specification discloses a technique for effectively correcting imbalance using a liquid balancer that operates by water injection. [Means for solving the problem]

[0013] The disclosed technology relates to a washing machine capable of performing a dewatering process.

[0014] The washing machine comprises a housing, a water-storable tub supported inside the housing via an elastic member, a drum rotatably supported inside the tub for storing laundry, a drive device for rotating the drum, an unbalance correction means for correcting the unbalance of the drum caused by the state of the laundry storage, and a controller for controlling the drive device and the unbalance correction means.

[0015] The unbalance correction means includes an annular trough attached to the peripheral edge of the drum and a water injection unit that injects water into the annular trough. The controller then corrects the drum's unbalance by operating the water injection unit during the execution of the dewatering process and adjusting the water injection state into the annular trough according to the rotation speed of the rotating drum.

[0016] In other words, with this washing machine, an annular trough is attached to the periphery of the drum, and the controller operates the water inlet when performing the spin-drying process, injecting water into the annular trough. Therefore, although an imbalance occurs in the rotating drum during the spin-drying process due to uneven distribution of laundry, the amount of water injected into the annular trough can adjust the trough to the optimal weight according to the amount of imbalance.

[0017] Furthermore, by adjusting the water flow into the annular trough according to the rotation speed of the rotating drum, the drum's imbalance is corrected. This allows water to be directed to the appropriate part of the annular trough corresponding to the drum's imbalance, effectively correcting the drum's imbalance.

[0018] Furthermore, since the annular gutter section is attached to the periphery of the drum, sufficient internal volume of the drum can be secured. Therefore, the washing machine's performance can be improved without significantly reducing the amount of laundry that can be washed.

[0019] Specifically, it further has imbalance information acquisition means capable of acquiring information regarding imbalance, and the controller has an imbalance state estimation unit that estimates the position and amount of the imbalance of the drum based on the information acquired by the imbalance information acquisition means, and the controller operates the water injection unit so that water is injected according to the amount of the estimated imbalance at a position facing the radial direction of the drum with respect to the estimated position of the imbalance. This is also possible.

[0020] If so, an appropriate amount of water can be injected so that the imbalance is canceled with respect to the estimated position and amount of the imbalance, and thus the imbalance of the drum can be effectively corrected.

[0021] The controller further has an imbalance state correction unit that operates the water injection unit to correct the imbalance, and the imbalance state correction unit may execute a plurality of exploratory water injections in which at least one of the start position and the end position of the water injection is different.

[0022] If so, the position of the true imbalance can be searched, and water can be injected in an optimal state, and the imbalance can be eliminated stably with high precision.

[0023] Specifically, the imbalance state correction unit may execute an individual estimation process for estimating the amount of imbalance in each of the exploratory water injections, and a selection process for selecting a dominant exploratory water injection with a small estimated amount of imbalance from the estimated amounts of imbalance in each of the exploratory water injections, and repeat the individual estimation process and the selection process.

[0024] If so, each time the individual estimation process and the selection process are repeated, it is possible to approach the optimal water injection position, and the imbalance can be eliminated stably with high precision.

[0025] More specifically, the imbalance state correction unit executes a first search step of performing the search water injection on the advanced angle side that injects water into a predetermined range that is relatively advanced in angle and the search water injection on the retarded angle side that injects water into a predetermined range that is relatively retarded in angle, and in the first search step, estimates the amount of imbalance of each of the search water injections on the advanced angle side and the retarded angle side, and executes a first selection process of selecting a first dominant search water injection having a small estimated amount from these estimated amounts, and based on the position of the first dominant search water injection, executes a second search step of performing the search water injection on the advanced angle side that injects water into a predetermined range that is relatively advanced in angle and the search water injection on the retarded angle side that injects water into a predetermined range that is relatively retarded in angle, and in the second search step, estimates the amount of imbalance of each of the search water injections on the advanced angle side and the retarded angle side, and executes a second selection process of selecting a second dominant search water injection having a small estimated amount from these estimated amounts, and if necessary, repeats the search step further.

[0026] By doing so, by repeating the search step, it is possible to surely approach the optimal water injection position. The imbalance can be eliminated stably with high accuracy.

[0027] After the repetition of the process related to the search is completed, the imbalance state correction unit may execute adjustment water injection that injects water until the amount of imbalance starts to increase based on the position of the dominant search water injection.

[0028] By doing so, the water injection amount can be increased at the optimal water injection position corresponding to the true imbalance position searched. And it can be brought into a state where it balances with the true imbalance. The imbalance can be eliminated stably with high accuracy.

[0029] The annular gutter portion may have a plurality of water storage cells partitioned by partition walls in the circumferential direction.

[0030] By doing so, since the water can be stored in small portions in each water storage cell, it becomes easy to store water in a predetermined range in the circumferential direction of the annular gutter portion. Therefore, the imbalance can be corrected more effectively.

[0031] Communication holes may be formed in the partition wall so that adjacent water storage cells can communicate with each other.

[0032] This reduces variations in the water levels within each reservoir cell. Water can freely move between the reservoir cells depending on the location of the imbalance. Therefore, imbalances can be corrected more effectively.

[0033] The annular trough portion may have an opening provided on its radially inner side to receive water from the water injection portion, and a water storage portion provided on its radially outer side to enable water storage by the action of centrifugal force.

[0034] This allows for the construction of a compact, annular trough section with a simple structure that can effectively correct imbalances.

[0035] The opening may face the central axis direction of the annular trough, and an annular return wall may be provided on the radially inner edge of the opening, projecting radially outward.

[0036] This prevents water from leaking out of the ring-shaped gutter and prevents laundry from getting wet during the spin cycle.

[0037] The direction in which water is injected into the opening may be tilted backward in the rotational direction with respect to the direction of the central axis of the annular trough.

[0038] This allows water to be injected smoothly without causing significant splashing.

[0039] The annular culvert further comprises a plurality of water storage cells partitioned by partition walls in the circumferential direction, The end edge of the partition wall facing the opening may be formed so as not to protrude outward from the opening.

[0040] This prevents water from being repelled during filling, which can reduce the efficiency of water filling.

[0041] The annular trough portion may have a water-receiving surface for receiving the injected water, and the angle at which the water is injected into the water-receiving surface may be set to 45 degrees or less.

[0042] This ensures high water injection efficiency and effectively corrects imbalances without negatively impacting the dewatering process.

[0043] The laundry loading opening may be provided on the front of the housing, and the water filling section may be located on the upper part of the tab, injecting water into the upper part of the rotating annular trough.

[0044] This corresponds to the case when applied to a so-called drum-type washing machine. By placing the water inlet at the top of the tub and injecting water into the top of the rotating annular trough, the water inlet can be made compact using existing piping.

[0045] The drum's rotational speed may decrease, causing the water to be drained from the annular culvert.

[0046] This allows for drainage as soon as the dewatering process is complete, minimizing residual water in the annular trough. Effective imbalance correction can then be achieved.

[0047] The laundry loading opening may be provided on the upper surface of the housing, and the annular trough may be positioned along an opening that opens at the upper end of the drum.

[0048] This corresponds to the case when applied to a so-called top-loading washing machine. It allows for effective correction of imbalance while ensuring sufficient drum volume. Therefore, it can improve the performance of the top-loading washing machine.

[0049] The laundry loading opening is provided on the front of the housing, the annular trough is positioned along an opening that opens at the front end of the drum, a sealing member is provided between the loading opening and the receiving opening of the tab to close the gap, and the nozzle portion of the water filling section is positioned so as to be covered by the sealing member.

[0050] This prevents dirty wash water from splashing and sticking to the nozzle. [Effects of the Invention]

[0051] The disclosed technology allows for the effective correction of imbalances using a liquid balancer powered by water injection. Therefore, the performance of the washing machine can be improved. [Brief explanation of the drawing]

[0052] [Figure 1] This is a schematic diagram of a washing machine (drum-type washing machine) to which the disclosed technology is applied. [Figure 2] This is a schematic cross-sectional view showing the area around the tab and water nozzle. [Figure 3] This is a schematic diagram showing the annular culvert section and the area around the water injection nozzle. [Figure 4] This is a diagram illustrating the detailed structure of the annular culvert. [Figure 5] Figure 4 is a schematic cross-sectional view of the annular culvert as seen from the arrow line Y1. [Figure 6] This is a diagram illustrating the design of a water storage cell. [Figure 7] This is a diagram illustrating the design of a water injection nozzle. [Figure 8] This diagram illustrates the effect of the water injection angle on water flow. [Figure 9] This is a block diagram of the controller and its related equipment. [Figure 10] This diagram illustrates unbalance correction control. [Figure 11] This diagram illustrates unbalance correction control. [Figure 12A] This diagram illustrates the state of the water supply during filling. [Figure 12B] This is a diagram illustrating the state during drainage. [Figure 13] This is a schematic diagram of a washing machine (top-loading washing machine) to which the disclosed technology is applied. [Figure 14] This diagram illustrates the conditions during water filling and draining. [Figure 15] This is a schematic diagram showing a modified version of the washing machine in Figure 1. [Figure 16] This diagram illustrates the challenges of unbalance correction control. [Figure 17A] This is a diagram illustrating the improved UB correction control. [Figure 17B] This is a diagram illustrating the improved UB correction control. [Figure 17C] This is a diagram illustrating the improved UB correction control. [Figure 18] This is a diagram illustrating the improved UB correction control. [Figure 19] This diagram illustrates the effects of the improved UB correction control. [Figure 20] This diagram illustrates the effects of the improved UB correction control. [Figure 21] This diagram illustrates the effects of the improved UB correction control. [Figure 22A] This is a flowchart of the improved UB correction control. [Figure 22B] This is a flowchart of the improved UB correction control. [Modes for carrying out the invention]

[0053] The following describes the technology being disclosed. However, the following description is essentially illustrative. The directions used in the description—front, back, left, right, and up and down—are based on the washing machine and follow the arrows shown in the diagram.

[0054] The term "unbalance (UB)" used in this explanation refers to a state where the distribution of laundry, pressed down by centrifugal force, is unevenly distributed circumferentially within the drum. Unbalance is caused by the center of gravity of the clump of laundry. If the laundry is not clumped together, the center of gravity of the main clump of laundry becomes the center of gravity of the unbalance. The position of the center of gravity of the laundry clump corresponds to the position of the unbalance. The mass of the laundry clump that makes up that center of gravity corresponds to the amount of unbalance.

[0055] <Overall structure of a washing machine> Figure 1 illustrates a washing machine 1 to which the disclosed technology is applied. This washing machine 1 is a so-called drum-type washing machine. Furthermore, this washing machine 1 is a so-called fully automatic type, and is configured to automatically perform a series of processes consisting of washing, rinsing, and spinning. It may also be capable of drying.

[0056] The washing machine 1 mainly consists of a housing 2, a tub 3, a drum 4, a drive unit 5, a water supply unit 7, a drainage unit 8, a controller 20, etc. In the case of this washing machine 1, an unbalance correction means 6 and an unbalance information acquisition means are provided so that the dewatering process can be performed efficiently and stably by applying the disclosed technology.

[0057] The casing 2 is a box-shaped container made of panels and a frame, and constitutes the outer casing of the washing machine 1. A circular opening 2a is formed on the front of the casing 2 for loading and unloading laundry. A door 2b with a transparent window is attached to the opening 2a. The opening 2a is opened and closed by the door 2b. An operating section 2c, which has switches and other controls for user operation, is installed above the opening 2a on the casing 2.

[0058] The tab 3 is housed inside the housing 2. As shown in Figure 2, the tab 3 consists of a bottomed cylindrical container capable of storing water. The tab 3 is positioned horizontally, meaning its opening 3a faces forward. Its central axis J is slightly inclined upward toward the front. The opening 3a has a smaller diameter than the tab 3. The tab 3 has an annular inner rim 3b around the opening 3a.

[0059] The inside of the tab 3 is in communication with the input port 2a because the receiving port 3a is connected to the input port 2a. Specifically, an elastically deformable ring-shaped diaphragm 10 (sealing member) is provided between the input port 2a and the receiving port 3a of the tab 3. The diaphragm 10 is attached to the tab 3 by joining it to the inner edge portion 3b. The diaphragm 10 seals the gap.

[0060] Tab 3 is supported inside the housing 2 via an elastic member. Specifically, multiple dampers 11 are installed at the bottom of the housing 2. Tab 3 is supported by these dampers 11. Furthermore, multiple coil springs 12 are installed at the top of the housing 2. Tab 3 is suspended by these coil springs 12.

[0061] Above tab 3, a water supply device 7 is provided, consisting of a water supply pipe 7a, a water supply valve 7b, and the like. The upstream end of the water supply pipe 7a protrudes outside the washing machine 1 and is connected to a water source (e.g., a water tap) not shown in the figure. The downstream end of the water supply pipe 7a is connected to the top of tab 3.

[0062] Above tab 3, there is a water injection section 61 which constitutes the unbalance correction means 6. This will be described separately.

[0063] A drain is provided at the bottom of tab 3. The drain is connected to the suction port of the drain pump 8b via the upstream drain pipe 8a. The downstream drain pipe 8c is connected to the discharge port of the drain pump 8b. The downstream drain pipe 8c is drawn out from the bottom of the housing 2 to the outside. A vibration sensor 13 is attached to tab 3 to detect vibrations of tab 3. The vibration sensor 13 constitutes an "unbalance information acquisition means".

[0064] The drum 4 consists of a bottomed cylindrical container with a slightly smaller diameter than the tab 3. The drum 4 is housed inside the tab 3 with its central axis J aligned with that of the tab 3. A circular rotating opening 4a faces the input opening 2a at the front end of the drum 4. Laundry is placed inside the drum 4 through the input opening 2a, the receiving opening 3a, and the rotating opening 4a.

[0065] The rotating port 4a has a smaller diameter than the drum 4. The drum 4 has an annular flange portion 4b around the rotating port 4a. The flange portion 4b faces the inner edge portion 3b of the tab 3. In this embodiment, the annular trough portion 60, which constitutes the unbalance correction means 6, is attached to the flange portion 4b. The annular trough portion 60 will be described separately.

[0066] The drum 4 has numerous dewatering holes 4c formed around its entire circumference (only a portion is shown in Figure 2). Additionally, several lifters 4d for stirring are attached to the inner surface of the drum 4. The front end of the drum 4 is rotatably supported at the receiving port 3a.

[0067] The drive unit 5 is installed at the rear of the tab 3. The drive unit 5 consists of a motor 5a, a shaft 5b, and the like. The shaft 5b is rotatably supported in the tab 3, passing through the rear of the tab 3. The tip of the shaft 5b protrudes into the interior of the tab 3 and is fixed to the center of the bottom of the drum 4. As a result, the drum 4 is rotatably supported inside the tab 3.

[0068] The motor 5a is mounted on the rear of the tab 3 and is connected coaxially to the shaft 5b. In other words, the drive unit 5 directly drives the drum 4 (a so-called direct drive system). As a result, the drum 4 rotates around the central axis J by the drive of the motor 5a.

[0069] A rotation sensor 14 is attached to the motor 5a to detect its rotation speed and rotation position. A current sensor 15 is attached to the inverter 5c attached to the motor 5a to detect the current flowing through the motor 5a. These rotation sensors 14 and current sensors 15 constitute an "unbalance information acquisition means".

[0070] The controller 20 is installed on top of the housing 2. The controller 20 comprehensively controls the operation of the washing machine 1, including the rotation of the motor 5a. The controller 20 consists of hardware such as a CPU and memory, and software such as control programs and various data.

[0071] The controller 20 controls the drive unit 5 (motor 5a), water supply valve 7b, drain pump 8b, etc., according to instructions input from the operation unit 2c. As a result, the washing machine 1 performs a series of processes including a washing process, a rinsing process, and a spin-drying process. The controller 20 further controls the unbalance correction means 6 during the spin-drying process.

[0072] <Means for correcting imbalance> During the spin-drying process, the drum 4 rotates at high speed with the laundry inside. However, the type and material of the laundry vary. Therefore, their weight and water absorption capacity differ before the spin-drying process. Furthermore, the position of the laundry changes within the rotating drum 4.

[0073] During the spin-drying process, the centrifugal force generated by the rotation of the drum 4 presses the laundry against the inner surface of the drum 4. At this time, the center of gravity of the rotating drum 4 becomes uneven due to the way the laundry is packed inside (so-called unbalance). As spin-drying progresses, the centrifugal force increases and the position of the laundry stabilizes. As the weight of the laundry decreases, the unbalance is reduced and the rotation of the drum 4 stabilizes. However, at the relatively low rotation speeds before this happens, abnormal vibrations can occur due to the unbalance.

[0074] To correct such imbalances, the washing machine 1 is equipped with a water-filling unbalance correction mechanism 6. The unbalance correction mechanism 6 has an annular trough 60 attached to the periphery of the drum 4 and a water-filling section 61 that injects water into the annular trough 60.

[0075] In addition to Figure 1, Figures 2 and 3 show the water injection section 61. In addition to Figures 1 and 3, Figures 4 and 5 show the annular culvert section 60.

[0076] In this embodiment, the water injection unit 61 is located on the upper part of the tab 3. In this embodiment, the annular trough 60 is located at the front end of the drum 4. Thus, the water injection unit 61 is configured to inject water into the upper part of the rotating annular trough 60. The water injection unit 61 consists of a water injection valve 61a, a water injection pipe 61b, a water injection nozzle 61c, and the like.

[0077] The water injection pipe 61b branches off from the water supply pipe 7a upstream of the water supply valve 7b. An openable / closable water injection valve 61a is installed near the branching point of the water injection pipe 61b. When the water injection valve 61a is opened, water is supplied through the water injection pipe 61b by the water pressure from the water source.

[0078] The tip of the water injection pipe 61b penetrates the diaphragm 10 and is housed inside the diaphragm 10. A water injection nozzle 61c is attached to the tip of the water injection pipe 61b. As shown in Figure 2, the water injection nozzle 61c is fixed by a bracket to the joint between the diaphragm 10 and the inner edge 3b of the tab.

[0079] As a result, the tip of the water injection pipe 61b and the area around the water injection nozzle 61c are covered by the diaphragm 10. This prevents the water injection nozzle 61c and other components from becoming dirty or accumulating due to the dirty cleaning water that accumulates inside the tab 3.

[0080] The water injection nozzle 61c penetrates the diaphragm 10 and the inner edge 3b, and its leading edge, where the outlet opens, is located inside the tab and faces the annular trough 60. Depending on the specifications of the washing machine 1, the water injection pipe 61b and the water injection nozzle 61c may not penetrate the diaphragm 10.

[0081] The water injection nozzle 61c sprays water in a straight line toward the annular trough 60. The annular trough 60 is a ring-shaped member, as shown in Figure 3. The annular trough 60 is attached to the flange portion 4b of the drum 4 so as to face the inner edge portion 3b of the tab 3, as shown in Figure 1.

[0082] The annular trough 60 has an annular opening 64 provided on its radially inner side and a water reservoir 65 provided on its radially outer side. The opening 64 faces the direction of the central axis J of the annular trough 60 (the front side in this embodiment).

[0083] More specifically, as shown in Figure 4, the annular trough 60 has a large-diameter, small-width cylindrical outer wall portion 60a, and annular first side wall portions 60b and second side wall portions 60c that extend radially inward parallel from both sides of the outer wall portion 60a. This forms a water storage portion 65 with an inverted U-shaped cross-section toward the radially outward direction. The water storage portion 65 becomes capable of storing water due to the action of centrifugal force.

[0084] The tip of the first side wall portion 60b is provided with a short, gently curved wall portion 60d that extends around its entire circumference. On the other hand, the second side wall portion 60c is connected to the inner circumferential wall portion 60f, which faces the outer circumferential wall portion 60a, via a gently curved intermediate wall portion 60e. The inner circumferential wall portion 60f is located radially inward from the tip of the curved wall portion 60d.

[0085] The tip of the inner circumferential wall portion 60f is located slightly outward from the first side wall portion 60b. In this embodiment, an annular return wall 60g is provided at the tip of the inner circumferential wall portion 60f, projecting radially outward. The tip of the return wall portion 60g is located radially inward from the tip of the bent wall portion 60d. As a result, there is an annular gap between the return wall portion 60g and the bent wall portion 60d. This gap forms an opening 64 that receives water from the water injection portion 61. In other words, the return wall 60g is provided at the radially inward edge of the opening 64.

[0086] Multiple through-holes 66 are formed at the base end of the return wall 60g. The return wall 60g suppresses the leakage of water injected into the annular trough 60 during rotation, while the drainage holes 66 prevent residual water in the annular trough 60 when it is not rotating.

[0087] As shown in Figure 5, the interior of the annular culvert 60 is divided into multiple sections at equal intervals in the circumferential direction by multiple partition walls 67. The division of the water storage section 65 by the partition walls 67 constitutes multiple water storage cells 68.

[0088] As shown in Figure 4, the opening 64 is also partitioned by a partition wall 67. However, the end edge 67a of the partition wall 67 facing the opening 64 is formed to be recessed inward so as not to protrude outward from the opening 64 (in other words, from the wall surface of the annular gutter 60). If the partition wall 67 protrudes outward from the opening 64, the water will be repelled during water injection, worsening the water injection efficiency. Therefore, forming it in this way suppresses the deterioration of water injection efficiency.

[0089] Furthermore, as shown by dashed lines in Figure 4, communication holes 69 may be formed in the partition wall 67 so that adjacent water storage cells 68 can communicate with each other. By forming communication holes 69, the water stored in each water storage cell 68 can move in and out of each other. This reduces the difference in the amount of water stored in each water storage cell 68 and allows for balanced water storage.

[0090] (Water storage cell design) In order to ensure stable water storage performance for each water storage cell 68, it is preferable to partition the water storage cells 68 within an appropriate range. Specifically, it is preferable to set the cell central angle θ1 of each water storage cell 68 to be between 10° and 30° (20°±10°).

[0091] As the annular trough 60 rotates with water stored in each water storage cell 68, the water surface (storage surface Sw) in each water storage cell 68 changes due to the effects of centrifugal force and gravity. Specifically, as shown in the upper part of Figure 6, if the surface extending tangentially to each water storage cell 68 is taken as the reference plane Rp, the higher the rotation speed, the closer the storage surface Sw approaches the reference plane Rp (left figure), and the lower the rotation speed, the more the storage surface Sw tilts from the reference plane Rp (right figure). In other words, the inclination angle θw that the storage surface Sw makes with respect to the reference plane Rp becomes larger.

[0092] If the slope of the reservoir surface Sw is steep, water is more likely to leak out of the reservoir cell 68 when it is full, thus reducing the amount of water that can be stored in the reservoir cell 68.

[0093] Furthermore, as shown in the lower part of Figure 6, the larger the water storage cell 68 is in the circumferential direction, the greater the influence of the slope of the water storage surface Sw, and the greater the slope (upper part). The smaller the water storage cell 68 is in the circumferential direction, the less the influence of the slope of the water storage surface Sw is, and the smaller the slope (lower part). In other words, the smaller the central angle (cell central angle θ1) of each water storage cell 68, the less the bias of the water storage surface Sw of each water storage cell 68 becomes, and the amount of water that can be stored also increases.

[0094] On the other hand, as the cell central angle θ1 decreases, the capacity of each water storage cell 68 decreases and the partition walls 67 increase. In other words, the total capacity of the annular culvert 60 decreases. Therefore, the inventors investigated and found an appropriate partition range for the water storage cells 68. That is, by setting the cell central angle θ1 to 20° or less and 10° or more (15° ± 5°), stable water storage performance of each water storage cell 68 can be ensured. In the washing machine 1 of this embodiment, the cell central angle θ1 is set to 15°.

[0095] (Water nozzle design) The water injection direction of the water injection nozzle 61c is preferably tilted backward within a predetermined range in the rotational direction with respect to the direction of the central axis J of the annular trough 60. Furthermore, it is preferable to direct the opening 64 with the radial direction of the annular trough 60 inclined from the outside to the inside within a predetermined range so as to approach the annular trough 60.

[0096] Figure 7 shows the arrangement of the water injection nozzle 61c and the annular trough 60. Due to the rotation of the annular trough 60, the water storage cell 68 moves to the right, as indicated by arrow Y2 in the upper figure. In contrast, the water injection direction of the water injection nozzle 61c is tilted backward in the direction of movement of the water storage cell 68, as indicated by arrow Y3. This allows water to be smoothly injected from the water injection nozzle 61c into the water storage cell 68 without causing significant splashing.

[0097] As described above, the cell central angle θ1 is set to 15°. Accordingly, the inventors investigated the range in which water can be smoothly injected into the water storage cell 68 without being obstructed by the partition wall 67. As a result, they found an appropriate range.

[0098] In other words, in the case of the washing machine 1, it is preferable to set the angle of the injected water tilted backward with respect to the direction of the central axis J of the annular trough 60, as viewed from above (backward tilt angle θ2), to be 30° ± 5°. In the washing machine 1 of this embodiment, the backward tilt angle θ2 is set to 30°.

[0099] It is preferable that most of the water (injected water) injected from the water injection nozzle 61c into the annular culvert 60 is directed towards the water storage section 65, that is, to ensure high injection efficiency. In contrast, the injected water collides with the inner wall surface of the annular culvert 60. That is, the annular culvert 60 has a water receiving surface 70 that receives the injected water. The dispersion state of the injected water that collides with the water receiving surface 70 changes depending on how it hits.

[0100] Figure 8 shows a simplified result of a simulation of flow division based on fluid dynamics, investigating the effect of the inclination angle of the injected water relative to the water receiving surface 70 (injection angle θ3) on the water flow. The injected water that collides with the water receiving surface 70 disperses. The area on the side where the injection is advancing is defined as q1, and the area on the side where the injection is receding is defined as q2.

[0101] The table in Figure 8 shows the proportion of water flow distributed within each range of q1 and q2 with respect to the water inlet angle θ3. It can be seen that when the water inlet angle θ3 reaches 45°, the proportion of q2 begins to increase rapidly relative to 45°, and the water inlet efficiency begins to deteriorate. From these results, it is preferable to set the water inlet angle θ3 to 45° or less. In the washing machine 1 of this embodiment, the water inlet angle θ3 is set to 45° by devising the position and shape of the opening 64.

[0102] Furthermore, the inner surface of the annular culvert 60 is composed of a continuous curved surface extending from the water receiving surface 70 to the water storage section 65. Therefore, the injected water received at the water receiving surface 70 flows smoothly towards the water storage section 65.

[0103] Furthermore, the water receiving surface 70 constantly moves as the annular culvert 60 rotates. The impact points of the water receiving surface 70 also shift continuously, which mitigates the dispersion of the injected water. Therefore, the injected water received by the water receiving surface 70 can be smoothly guided to the water storage section 65. High water injection efficiency can be ensured.

[0104] <Unbalance Correction Control> Figure 9 shows a block diagram of the controller 20 and its related equipment involved in unbalance correction control. The controller 20 receives information from the vibration sensor 13, the rotation sensor 14, and the current sensor 15 (unbalance information acquisition means). Based on this information, it outputs control signals to the motor and the water inlet valve 61a.

[0105] As a result, the controller 20 operates the water injection unit 61 during the dewatering process, adjusting the water injection state into the annular trough 60 according to the rotation speed of the rotating drum 4. In doing so, it corrects the imbalance of the drum 4 (unbalance correction control).

[0106] Specifically, the controller 20 has, as a functional configuration, an unbalance state estimation unit 21, a water injection control unit 22, and a drive control unit 23. The drive control unit 23 controls the drive of the motor 5a so that the drum 4 rotates according to each step of the washing process. The water injection control unit 22 controls the opening and closing of the water injection valve 61a during unbalance correction control.

[0107] The unbalance correction unit 24 will be described separately later.

[0108] The unbalance state estimation unit 21 estimates the location and amount of unbalance in the drum 4 based on the information acquired by the unbalance information acquisition means (in this embodiment, the vibration sensor 13, the rotation sensor 14, and the current sensor 15). Such an unbalance state estimation method can be selected from known technologies according to the specifications.

[0109] The water injection control unit 22 operates the water injection valve 61a so that water is injected in proportion to the estimated amount of unbalance, centered on a position on the drum 4 that is radially opposite to the estimated unbalance location. A specific example is shown in Figure 10.

[0110] Figure 10 is a simplified diagram of the drum 4 in the dewatering process, viewed from the front. The drum 4 is rotated clockwise around its central axis J. The unbalance state estimation unit 21 estimates the unbalance position CG and amount W of the laundry. The controller 20 obtains the position (unbalance opposing position OP) radially opposite to the estimated unbalance position CG.

[0111] The controller 20 then operates the water injection valve 61a so that water is injected into the annular trough 60 in accordance with the amount of unbalance W, within a range (water injection range R1) where the central angle is ±90° around the unbalance opposing position OP.

[0112] (Specific examples of imbalance control during dehydration) The upper diagram in Figure 11 shows the profile of the spin-drying process of washing machine 1. The spin-drying process begins when the rinsing process is completed and the rinse water is drained from tab 3.

[0113] In the initial stages of the dewatering process, drum 4 is rotated at a low speed. This allows for an estimation of the imbalance. In some cases, a preliminary dewatering treatment is performed, temporarily increasing the rotation speed to correct the imbalance.

[0114] After that, the rotation speed of drum 4 is increased to a predetermined rotation speed r2 of 1000 rpm or more (main dewatering process). After being held in that state for a certain period of time, it is decelerated and the dewatering process ends.

[0115] In the unbalance correction control, the water injection process into the annular trough 60 is performed in the initial stage of the dewatering process when the rotational speed of the drum 4 is less than a predetermined rotational speed r1 (for example, the rotational speed at which the washing machine 1 resonates).

[0116] The controller 20 (water injection control unit 22) controls the opening and closing of the water injection valve 61a according to the rotation speed of the drum 4, thereby intermittently injecting water. Specifically, as shown in the middle diagram of Figure 11, the water injection valve 61a is opened (water injection valve 61a ON operation) at a timing when water can be injected into the injection range R1, according to the rotation of the drum 4. The water injection valve 61a is closed (water injection valve 61a OFF operation) at a timing when water cannot be injected into the injection range R1.

[0117] Figure 12A shows the state during water injection. As described above, a straight stream of water is injected into the annular culvert 60 from the water injection nozzle 61c. The injected water is received by the water receiving surface 70 and then guided to the water storage section 65. Since the annular culvert 60 is rotating, water is stored in the water storage section 65 by the action of centrifugal force, as shown by the arrow line Y4.

[0118] Because the water is distributed and stored in each water storage cell 68 with an optimized capacity, it offers excellent water storage efficiency with a sufficient amount of water, and can stably store water within the appropriate range. The position of the water injection nozzle 61c has also been carefully designed to suppress water splashing.

[0119] Intermittent watering controlled by the controller 20 allows for selective watering within the watering range R1 without watering outside the watering range R2, as shown in the lower diagram of Figure 11. By repeatedly injecting water intermittently, the amount of water stored in the watering range R1 can be increased. When the amount of water stored in the watering range R1 reaches the estimated amount of imbalance W, watering is stopped. This can offset the imbalance of the center of gravity caused by the state of the laundry load and correct the imbalance of the drum 4.

[0120] Subsequently, the controller 20 increases the rotational speed of the drum 4 and performs the main dewatering process. Due to the action of centrifugal force, the water stored in each water storage cell 68 is retained. When the main dewatering process is completed, the motor is decelerated and the rotational speed of the drum 4 decreases.

[0121] Then, when the rotational speed of the drum 4 reaches a predetermined low rotational speed, as shown in the upper diagram of Figure 12B, the centrifugal force weakens and the water stored in each water storage cell 68 is gradually drained. In other words, the water is drained from the annular trough 60 as the rotational speed of the drum 4 decreases.

[0122] In this washing machine 1, a return wall 60g is provided in the annular gutter section 60. This allows for rapid drainage, suppressing large splashes of water and preventing the laundry from getting wet.

[0123] Furthermore, since the return wall 60g has drainage holes 66, water can be drained through the drainage holes 66, as shown in the lower diagram of Figure 12B. Therefore, water can be drained without leaving any inlet in the annular trough 60.

[0124] <Another Embodiment> The disclosed technology can also be applied to top-loading washing machines. Figure 13 shows a simplified example (washing machine 1B). Even though it is a top-loading machine, its basic equipment is the same as that of a front-loading machine. Therefore, the same reference numerals are used for components that have the same function as those in washing machine 1, and their explanations are simplified or omitted.

[0125] In the case of washing machine 1B, the loading opening 2a is located on the top surface of the housing 2. Accordingly, the tab 3 is also positioned vertically. Therefore, the annular trough 60 of this washing machine 1B is positioned along the rotating opening 4a that opens at the upper end of the drum 4. The water inlet nozzle 61c is located at the rear of the washing machine 1B, that is, near the water inlet valve 61a.

[0126] Figure 14 shows a magnified view of the annular gutter section 60 and its installation location. In the case of a vertical washing machine 1B, the flange section 4b faces upward. An annular extension section 80 is provided at the upper end of the drum 4, extending upward from the flange section 4b. The annular gutter section 60 is attached to this annular extension section 80.

[0127] The lower surface of the annular trough portion 60 faces the flange portion 4b with a gap in between. At the boundary between the annular extension portion 80 and the flange portion 4b, several outer through holes 81 are formed that penetrate the annular extension portion 80 inward and outward. The annular trough portion 60 in this embodiment does not have a return wall 60g. On the other hand, at the boundary between the second wall portion and the inner circumferential wall portion 60f, several inner through holes 82 are formed that penetrate the inner circumferential wall portion 60f inward and outward.

[0128] The upper diagram in Figure 14 shows the state during water injection. As indicated by the arrow, water is injected in a straight line from the injection nozzle 61c into the annular trough 60. The injected water is received by the water receiving surface 70 and then guided into the water storage section 65. Because the annular trough 60 is rotating, the water is stored radially outward of the water storage section 65 due to the action of centrifugal force.

[0129] Intermittent water injection controlled by the controller 20 injects water into the annular trough 60 corresponding to the estimated unbalance position CG and amount W. This can offset the imbalance in the center of gravity caused by the state of the laundry load and correct the unbalance of the drum 4.

[0130] Once the main dewatering process is complete, the motor 5a is decelerated, and the rotational speed of the drum 4 reaches a predetermined low speed. As shown in the lower part of Figure 14, as the centrifugal force weakens, gravity causes the water stored in each water storage cell 68 to gradually accumulate on the lower side of the annular trough 60. The water is then drained from the annular trough 60 through the inner through-holes 82.

[0131] The drainage from the annular trough 60 flows into the gap below it. Furthermore, since the annular extension 80 has an external through-hole 81, the water can be drained from the drum 4 to the tab 3 through the external through-hole 81. Therefore, once the dewatering process is complete, all water can be drained from the annular trough 60 without leaving any behind.

[0132] <Variation> Figure 15 shows a modified version of washing machine 1 (washing machine 1C). In washing machine 1C, the annular gutter 60 is installed not only at the front end of the drum 4 but also at the rear end. Except for the fact that the orientation of the water inlet nozzle 61c and the annular gutter 60 is reversed and the front and rear are symmetrical, the unbalance correction means 6 at the rear end is the same as the configuration at the front end.

[0133] As described above, providing unbalance correction means 6 at both the front and rear increases the degree of control freedom. Therefore, unbalance correction can be performed more stably.

[0134] In the case of a vertical washing machine 1B, an unbalance correction means 6 can be added to the lower end of the drum 4. However, in this case, the orientation of the water inlet nozzle 61c and the annular gutter 60 will be the same as the configuration at the upper end.

[0135] <Application examples of unbalance correction control> This section describes unbalance correction control (improved UB correction control), which enables stable and highly accurate correction of imbalances.

[0136] (Challenges of unbalance correction control) As mentioned above, in order to correct an imbalance, it is common practice to first estimate the imbalance state (its location and amount) using an imbalance information acquisition method. However, estimating the imbalance state is difficult and usually involves estimation errors.

[0137] Figure 16 shows the unbalance correction control before such improvements. The black arrow indicates the water injection position. PUB is the true unbalance position of the laundry. In contrast, Ps represents the estimated unbalance position. In this case, there is an error of about 40°. The degree of error varies, but an error of this magnitude is usually possible.

[0138] In this case, based on the estimated unbalance position Ps, the controller 20 operates the water inlet valve 61a so that water is injected into the annular culvert 60 in a range where the central angle is ±90° around the unbalance opposing position OP, according to the amount of unbalance W, as shown in the upper diagram of Figure 16.

[0139] Based on the estimated unbalance position Ps, water injection continues according to the estimated amount of unbalance. As a result, the situation is as shown in the lower part of Figure 16. In other words, if the estimation of the unbalance state contains errors, water will be injected into a range that is deviated from the true unbalance opposing position, and therefore the unbalance cannot be properly corrected.

[0140] Therefore, the improved UB correction control searches for the unbalanced position by performing multiple exploratory water injections, each time with at least one of the start or end positions of the water injection being different.

[0141] (Improved UB correction control) As shown in Figure 9, in the case of washing machine 1, an application example that implements improved UB correction control, the controller 20 further includes an unbalance state correction unit 24. Washing machine 1 in the application example is equipped with a vibration sensor 13 that detects vibration of the tub. The unbalance state correction unit 24 utilizes the vibration sensor 13. To correct the unbalance, the unbalance state correction unit 24 works in cooperation with the water injection control unit 22 to operate the water injection valve 61a.

[0142] Then, the unbalance correction unit 24 performs multiple exploratory water injections, each time with at least one of the start or end positions of the water injection being different.

[0143] In detail, the process involves an individual estimation process to estimate the amount of imbalance for each exploratory injection, and a selection process to select the exploratory injection with the smallest estimated amount of imbalance from among the estimated amounts of imbalance for each of the exploratory injections. These individual estimation and selection processes are repeated until the imbalance state stabilizes. Specifically, the process may be carried out as follows.

[0144] The unbalance correction unit performs an advance-side search injection, which injects water into a predetermined range that is relatively advanced, and a retard-side search injection, which injects water into a predetermined range that is relatively retarded (first search step). In the first search step, the amount of unbalance for each of the advance-side and retard-side search injections is estimated, and a first superior search injection with a smaller estimated amount is selected from these estimated amounts (first selection process).

[0145] Then, based on the position of the first dominant search injection, a search injection on the advance side is performed, which injects water into a predetermined range that is relatively advanced, and a search injection on the retard side is performed, which injects water into a predetermined range that is relatively retarded (second search step). In the second search step, the amount of imbalance in each of the search injections on the advance side and retard side is estimated, and from these estimated amounts, the second dominant search injection with the smaller estimated amount is selected (second selection process). If necessary, the third and fourth search steps are repeated.

[0146] Figures 17A, 17B, and 18 show a specific example of the improved UB correction control.

[0147] Similar to the pre-improvement version, the unbalance state estimation unit 21 estimates the location and amount of the unbalance based on the information acquired by the unbalance information acquisition means. Then, as shown in the upper diagram of Figure 17A, the water injection control unit 22, in cooperation with the unbalance state correction unit 24, operates the water injection valve 61a so that water is injected into a range that is advanced by a predetermined angle in the rotational direction (shifted to the front in the rotational direction) relative to the unbalance opposing position OP based on the estimation result (first advance water injection: equivalent to search water injection).

[0148] The amount of water injected in the first advance water injection is small (for example, 50g). This amount is sufficiently less than the amount of imbalance. The water injection control unit 22 repeats the first advance water injection several to several dozen times. Simultaneously with the first advance water injection, the unbalance state correction unit 24 uses the vibration sensor 13 to detect vibrations of tab 3. Vibrations of tab 3 are detected from the start to the end of the first advance water injection.

[0149] As water is injected into the side of the unbalanced opposing position OP, the vibration of tab 3 decreases. The unbalanced state correction unit 24 calculates the amount of change in the vibration amount (e.g., amplitude) (vibration change amount ΔVa) from the detected data. For example, the difference between the amplitude at the start of advance-angle water injection and the amplitude at the end of advance-angle water injection may be used as the vibration change amount ΔVa.

[0150] Next, as shown in the lower diagram of Figure 17A, the water injection control unit 22 operates the water injection valve 61a so that water is injected into a range that is retarded by a predetermined angle in the direction of rotation (shifted to the rear in the direction of rotation) relative to the unbalanced opposing position OP (first retarded water injection: equivalent to search water injection).

[0151] The amount of water injected in the first retarded injection is also small. The injection control unit 22 repeats the first retarded injection several times to several dozen times. Simultaneously with the first retarded injection, the unbalance state correction unit 24 detects vibration of tab 3. Vibration of tab 3 is detected from the start to the end of the first retarded injection.

[0152] Since water is injected to the side of the unbalanced opposing position OP, the vibration of tab 3 generally decreases. The unbalanced state correction unit 24 calculates the amount of change in the vibration amount (e.g., amplitude) (vibration change amount ΔVr) from the detected data. For example, the difference between the amplitude at the start of retarded water injection and the amplitude at the end of retarded water injection may be used as the vibration change amount ΔVr.

[0153] After that, the unbalance state correction unit 24 compares the magnitudes of the two calculated vibration change amounts ΔVa and ΔVr. Then, it selects the search injection with the smaller vibration change amount as the superior search injection (selection process). In the illustrated example, the first advance-angle injection becomes the superior search injection. This series of processes corresponds to the first search step.

[0154] Next, as shown in the upper diagram of Figure 17B, the water injection control unit 22 operates the water injection valve 61a so that water is injected into a range advanced by a predetermined angle in the rotational direction relative to the water injection position of the superior search water injection selected in the first search step (second advance water injection). Note that the degree of advance is smaller for the second advance water injection than for the first advance water injection.

[0155] The water injection control unit 22 repeats the second advance-angle water injection in the same manner as the first search step. Simultaneously with the second advance-angle water injection, the unbalance state correction unit 24 detects vibration of tab 3. The unbalance state correction unit 24 calculates the second vibration change amount ΔVa from the detected data.

[0156] Next, as shown in the lower diagram of Figure 17B, the water injection control unit 22 operates the water injection valve 61a so that water is injected into a range that is retarded by a predetermined angle in the rotational direction relative to the injection position of the superior search injection (second retarded injection). The water injection control unit 22 repeats the second retarded injection in the same manner as the first search step. Note that the degree of retardation is smaller for the second retarded injection than for the first retarded injection.

[0157] Simultaneously with the second retarded water injection, the unbalance state correction unit 24 detects vibration of tab 3. From this detected data, the unbalance state correction unit 24 calculates the second vibration change amount ΔVr.

[0158] After that, the unbalance state correction unit 24 compares the magnitudes of the two calculated second vibration change amounts ΔVa and ΔVr. Then, it selects the search injection with the smaller vibration change amount as the second superior search injection (selection process). In the illustrated example, the second advance-angle injection becomes the second superior search injection. This series of processes corresponds to the second search step.

[0159] Next, as shown in the upper diagram of Figure 17C, the water injection control unit 22 operates the water injection valve 61a so that water is injected into a range advanced by a predetermined angle in the rotational direction relative to the water injection position of the second priority search water injection (third advance water injection). Note that the degree of advance is smaller for the third advance water injection than for the second advance water injection.

[0160] The water injection control unit 22 repeats the third advance-angle water injection in the same manner as the first and second search steps. Simultaneously with the third advance-angle water injection, the unbalance state correction unit 24 detects vibration of tab 3. The unbalance state correction unit 24 calculates the third vibration change amount ΔVa from the detected data.

[0161] Next, as shown in the lower diagram of Figure 17C, the water injection control unit 22 operates the water injection valve 61a so that water is injected into a range that is retarded by a predetermined angle in the rotational direction relative to the water injection position of the second priority search injection (third retarded injection). The water injection control unit 22 repeats the third retarded injection in the same manner as the first and second search steps. Note that the degree of retardation is smaller for the third retarded injection than for the second retarded injection.

[0162] Simultaneously with the third retarded water injection, the unbalance state correction unit 24 detects vibration of tab 3. From the detected data, the unbalance state correction unit 24 calculates the third vibration change amount ΔVr.

[0163] After that, the unbalance state correction unit 24 compares the magnitudes of the two calculated third vibration change amounts ΔVa and ΔVr. Then, it selects the search injection with the smaller vibration change amount as the third superior search injection (selection process). In the illustrated example, the third advance-angle injection becomes the third superior search injection.

[0164] As shown in Figures 17A to 17C, the overlap area between advanced-angle and retarded-angle watering increases with each exploration step. In other words, the dominant exploration watering approaches an unbalanced position.

[0165] Considering the estimation error of the unbalance location, a practically appropriate unbalance location can be reached in three search steps. The unbalance state correction unit 24 determines the center position of the water injection range of the third superior search water injection as the true unbalance opposing position. The unbalance state correction unit 24 then terminates the search step.

[0166] Subsequently, the unbalance state correction unit 24 performs an UB amount adjustment step. Specifically, after the repetition of the search step is completed, the unbalance state correction unit 24 performs adjustment water injection, which is injected based on the position of the last superior search water injection, until the amount of unbalance begins to increase.

[0167] Figure 18 shows an example of the UB amount adjustment step. The water injection control unit 22 operates the water injection valve 61a so that water is injected into the injection range of the third priority search injection (adjustment injection). The amount of water injected for adjustment injection can also be small (for example, 50g). The water injection control unit 22 repeats the adjustment injection. Simultaneously with the adjustment injection, the unbalance state correction unit 24 detects the vibration Vf of tab 3 from the start of advance-angle injection.

[0168] Since water is injected against the true unbalanced position, the vibration Vf of tab 3 decreases until it balances with the true amount of unbalance. Once it exceeds the point where it balances with the true amount of unbalance, the unbalance actually increases. As a result, the vibration Vf of tab 3 begins to increase. Therefore, the unbalance state correction unit 24 detects the inflection point where the vibration Vf of tab 3 begins to increase from the detected data.

[0169] The water injection control unit 22 terminates the regulated water injection when the vibration Vf of tab 3 reaches an inflection point where it begins to increase. This balances the water injection with the position and amount of the true imbalance. The imbalance is then eliminated in an optimal state.

[0170] Figure 19 shows an example of the change in the amount of unbalance during the UB correction process using the improved UB correction control as measured in actual tests. With each exploratory water injection, the water approaches the optimal injection position. As a result, the position of the unbalance is corrected, and the amount of unbalance gradually decreases. Then, with the adjustment water injection at the optimal injection position, the amount of unbalance is balanced, and the amount of unbalance is resolved in an optimal state.

[0171] Figure 20 shows the relationship between the angular error between the estimated unbalance position and the true unbalance position obtained from the test, and the angular error between the actual water injection position and the optimal water injection position. The dashed line represents the UB correction control before improvement. The solid line represents the improved UB correction control.

[0172] In the pre-improvement UB correction control, as mentioned above, the water injection position did not change from the initial angular error. In contrast, with the improved UB correction control, it was confirmed that even if the estimated error of the unbalance position was close to 100°, the water injection position could be corrected to a deviation of only a few degrees. However, due to the influence of the spacing between the water storage cells (15°), even if the number of search injections was increased, the angular error of the water injection position tended to remain at around 15°. Three search steps are the most efficient number of steps.

[0173] Figure 21 shows the relationship between the angular error between the estimated unbalance position and the true unbalance position obtained from the test, and the amount of unbalance remaining in the UB correction control. The dashed line represents the UB correction control before improvement. The solid line represents the improved UB correction control. In the test, 700g of water was added using the UB correction control to an initial UB amount of 700g.

[0174] In the previous UB correction control, the amount of remaining unbalance increased proportionally to the estimation error of the unbalance position. In contrast, with the improved UB correction control, the amount of unbalance was resolved optimally up to an estimation error of nearly 60° of the unbalance position. It was confirmed that the unbalance could be resolved over a wide range and that it was highly robust.

[0175] (Flow of improved UB correction control) Figures 22A and 22B show the flow of the improved UB correction control performed by the controller 20. The controller 20 reads various measurement data (step S1). Then, it estimates the location (amount) of the unbalance (step S2).

[0176] Once the location (amount) of the imbalance is estimated, the controller 20 starts advancing the water injection based on the estimation result (step S3). At the same time as advancing the water injection, the controller 20 detects the vibration of tab 3. After advancing the water injection is complete, the controller 20 calculates the vibration change amount ΔVa (steps S4, S5).

[0177] Next, the controller 20 starts retarded irrigation (step S6). Once retarded irrigation is complete, the controller 20 calculates the change in oscillation ΔVr (steps S7, S8). Then, the controller 20 compares the magnitudes of the two values, ΔVa and ΔVr (step S9).

[0178] As a result, if the change in vibration ΔVr for retarded injection is smaller than the change in vibration ΔVa for advanced injection (No in step S9), the controller 20 determines that there is a true unbalanced opposing position on the advanced side and selects the advanced side (step S10).

[0179] Conversely, if the vibration change ΔVr for retarded-angle water injection is smaller than the vibration change ΔVa for advanced-angle water injection, the controller 20 determines that the true unbalanced opposing position is on the retarded-angle side and selects the retarded-angle side (step S11).

[0180] The controller 20 determines whether the water injection position has been determined (step S12). For example, the search step may be set to 3 times, and the determination may be made based on whether it has been performed 3 times. Alternatively, the determination may be made based on whether it has reached or below a predetermined determination value (target vibration change amount).

[0181] The controller 20 repeats a series of processes corresponding to the search step until positioning is completed (steps S3 to S11). On the other hand, once it determines that positioning is complete, the controller 20 starts adjusting the water injection (step S13).

[0182] The controller 20 determines whether the vibration Vf of tab 3 has started to increase (step S14). If it determines that the vibration Vf of tab 3 has started to increase, it terminates the adjustment water injection (step S15). This terminates the improved UB correction control. The controller 20 increases the rotation speed of tab 3 and proceeds to the main dewatering process.

[0183] <Other> The disclosed technology is not limited to the embodiments described above, but also includes various other configurations. For example, the water inlet 61 of the washing machine 1 may be located at the bottom of the tab 3 and configured to inject water into the bottom of the rotating annular trough 60. The water inlet 61 of the washing machine 1 may also be located on the side of the tab 3.

[0184] In the embodiment described above, water was supplied using an external water source having a predetermined water pressure. However, it is not limited to this; for example, a water supply pump may be attached to the housing 2, and water may be supplied using its water pressure.

[0185] In the embodiments described above, examples were given in which the annular trough 60 is installed only at the front end of the drum 4, or at both the front and rear ends. However, the annular trough 60 may be installed only at the rear end of the drum 4. In the case of a vertical type, it may be installed only at the lower end of the drum 4.

[0186] Dehydration is primarily performed in the final stage of washing. However, dehydration may also occur during the rinsing process. The disclosed technology includes this concept of dehydration, even outside of the final stage.

[0187] Regarding the improved UB correction control, estimating the unbalance state is not essential. The location of the unbalance can be identified without estimating the unbalance state through repeated search water injection and selection processes, i.e., the repeated search step. This eliminates the need for an unbalance information acquisition method, resulting in cost savings. However, this may increase the number of search iterations.

[0188] While three search steps are practically optimal, two or more may be used depending on the specifications. Alternatively, instead of defining the number of steps, a predetermined target value may be set to determine the end of the search, and the search steps may be repeated until that target value is reached. The number of advance and retard injections is not limited to two. If the injection range is shifted in the circumferential direction, the number of advance and retard injections may be three or more. [Explanation of symbols]

[0189] 1. Washing machine 2 cabinets 3 tabs 4 drums 5. Drive unit 6. Unbalance Correction Means 7 Water supply device 8 Drainage system 10 diaphragms 13. Vibration sensor (means for acquiring unbalance information) 14. Rotation sensor (means for acquiring unbalance information) 15. Current sensor (means for acquiring unbalance information) 20 controllers 21 Imbalance state estimation unit 22 Water Injection Control Unit 23 Drive control unit 24. Unbalance Correction Unit 60 Ring-shaped culvert 60g Reverse wall 61 Water Inlet 61a Water Inlet Valve 61b Water injection pipe 61c Water Injection Nozzle 64 openings 65 Water storage section 66 Drain hole 67 Partition Wall 68 water storage cells 69 Communication hole 70 Water receiving surface 80 Annular extension 81 Outer through hole 82 Inner through hole J center axis

Claims

1. A washing machine capable of performing a dehydration process, The casing and A water-storable tab is supported inside the housing via an elastic member, A drum for holding laundry is pivotally supported inside the aforementioned tab in a rotatable manner, A drive device for rotating the drum, An unbalance correction means for correcting the imbalance of the drum caused by the state of the laundry being loaded, A controller that controls the drive device and the unbalance correction means, Equipped with, The aforementioned unbalance correction means is An annular groove portion attached to the peripheral edge of the drum, The annular section includes a water injection section for injecting water into the aforementioned annular section, It has, A washing machine in which the controller operates the water supply unit when the dewatering process is executed and adjusts the water supply state to the annular trough according to the rotation speed of the rotating drum, thereby correcting the imbalance of the drum.

2. In the washing machine according to claim 1, The system further includes means for acquiring imbalance information that can obtain information regarding imbalances. The controller has an unbalance state estimation unit that estimates the position and amount of the drum's unbalance based on the information acquired by the unbalance information acquisition means. A washing machine in which the controller operates the water dispensing unit so that water is dispensed at a position radially opposite to the estimated unbalance position of the drum, in proportion to the estimated amount of the unbalance.

3. In the washing machine according to claim 1 or 2, The controller further includes an unbalance state correction unit that operates the water injection unit in order to correct the imbalance, The washing machine wherein the unbalance correction unit performs multiple exploratory water injections in which at least one of the start position and end position of the water injection is different.

4. In the washing machine according to claim 3, The aforementioned unbalance state correction unit, An individual estimation process for estimating the amount of imbalance in each of the aforementioned exploratory water injections, A selection process to select the superior exploratory water injection with the smallest estimated imbalance from among the estimated imbalances of each of the exploratory water injections, Execute, A washing machine that repeats the individual estimation process and the selection process.

5. In the washing machine according to claim 4, The aforementioned unbalance state correction unit, The first search step is performed, which involves performing the advance-angle search water injection, which involves injecting water into a predetermined range that is relatively advanced, and the retard-angle search water injection, which involves injecting water into a predetermined range that is relatively retarded. In the first search step, the amount of imbalance in the advance and retard side of the search injection is estimated, and the first selection process is performed to select the first superior search injection with the smaller estimated amount from among these estimated amounts. Based on the first superior search water injection position, the second search step is performed, which involves performing the advance-angle search water injection to inject water into a predetermined range that is relatively advanced, and the retard-angle search water injection to inject water into a predetermined range that is relatively retarded. In the second search step, the amount of imbalance in the advance and retard side of the search injection is estimated, and the second selection process is performed to select the second superior search injection with the smaller estimated amount from among these estimated amounts. The washing machine repeats the aforementioned search step as needed.

6. In the washing machine according to claim 4 or 5, A washing machine in which, after the repeated processing related to the search is completed, the unbalance state correction unit performs adjustment water injection, which injects water based on the position of the superior search water injection until the amount of unbalance begins to increase.

7. In the washing machine according to claim 1, A washing machine having a plurality of water storage cells, the annular trough portion of which is partitioned by partition walls in the circumferential direction.

8. In the washing machine according to claim 7, A washing machine in which communication holes are formed in the partition wall so that adjacent water storage cells can communicate with each other.

9. In the washing machine according to claim 1, The aforementioned annular culvert portion, An opening is provided on the radially inner side to receive water from the water injection section, A water storage section is provided on the radially outer side, which is capable of storing water due to the action of centrifugal force, A washing machine that has [this feature].

10. In the washing machine according to claim 9, The washing machine wherein the opening faces the central axis direction of the annular trough, and an annular return wall is provided on the radially inner edge of the opening, projecting radially outward.

11. In the washing machine according to claim 9, A washing machine in which the direction of water injection into the opening is tilted backward in the rotational direction with respect to the direction of the central axis of the annular gutter.

12. In the washing machine according to claim 9, The annular culvert further comprises a plurality of water storage cells partitioned by partition walls in the circumferential direction, A washing machine in which the end edge of the partition wall facing the opening is formed so as not to protrude outward from the opening.

13. In the washing machine according to claim 9, The annular section has a water-receiving surface that receives the water being injected, A washing machine in which the water injection angle to the water receiving surface is set to 45 degrees or less.

14. In the washing machine according to claim 1, A laundry loading opening is provided on the front of the housing. A washing machine in which the water injection unit is located on the upper part of the tab and water is injected into the upper part of the rotating annular trough.

15. In the washing machine according to claim 1, A washing machine in which the rotational speed of the drum decreases, causing water to be drained from the annular gutter.

16. In the washing machine according to claim 15, A laundry loading opening is provided on the top surface of the housing. A washing machine in which the annular trough portion is positioned along an opening that opens at the upper end of the drum.

17. In the washing machine according to claim 1, A laundry loading opening is provided on the front of the housing. The annular trough portion is positioned along the opening that opens at the front end of the drum, A sealing member is provided between the input opening and the receiving opening of the tab to close the gap. A washing machine in which the area around the nozzle portion of the water inlet is covered by the sealing member.

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