Washing machine

Abstract

To provide a washing machine capable of achieving performance required by users at a high level.SOLUTION: A washing machine of an embodiment comprise a water tub, a rotary tub, a motor, a vibration detecting section, a determination section, and a threshold value changing section. The rotary tub is disposed in the water tub and houses clothing. The motor rotates the rotary tub. The vibration detecting section detects values relating to vibration of the water tub or the rotary tub. The determination section determines procedure of dewatering operation based on the value detected by the vibration detecting section and the threshold value. With respect to the threshold value used at a first dewatering process performed in the middle of a series of washing operation, the threshold changing section changes the threshold value used at a second dewatering process performed at the end of the washing operation.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] Embodiments of the present invention relate to washing machines.

Background Art

[0002] Washing machines that monitor vibration using a threshold value are known. By the way, it is desirable that the washing machine can achieve the performance required by the user at a higher level.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the present invention is to provide a washing machine capable of achieving the performance required by the user at a high level.

Means for Solving the Problems

[0005] The washing machine according to the embodiment includes a water tub, a rotary tub, a motor, a vibration detection unit, a determination unit, and a threshold value change unit. The rotary tub is disposed in the water tub and clothes are accommodated therein. The motor rotationally drives the rotary tub. The vibration detection unit detects a value related to the vibration of the water tub or the rotary tub. The determination unit makes a determination regarding how to proceed with the dehydration operation based on the value detected by the vibration detection unit and a threshold value. The threshold value change unit changes the threshold value used in a second dehydration process performed at the end of the washing operation with respect to the threshold value used in a first dehydration process performed during a series of washing operations. The threshold value changing unit reduces the threshold value used in the second dehydration process with respect to the threshold value used in the first dehydration process.

Brief Description of the Drawings

[0006]

Figure 1

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Mode for Carrying Out the Invention

[0007] Hereinafter, the washing machine according to the embodiment will be described with reference to the drawings. In the following description, the same reference numerals are given to configurations having the same or similar functions. And redundant descriptions of these configurations may be omitted. "Based on XX" means "based at least on XX", and may include cases based on other elements in addition to XX. "Based on XX" is not limited to the case of directly using XX, and may include cases based on those obtained by performing operations or processing on XX. "XX or YY" is not limited to either one of XX and YY, and may include both cases of XX and YY. This is the same when there are three or more selectable elements. "XX" and "YY" are arbitrary elements (for example, arbitrary information). In this application, the "washing machine" may include a washing and drying machine having a drying function. In this application, the "rotation speed" means the number of rotations per unit time. That is, the "rotation speed" is used in the sense corresponding to the "rotation rate".

[0008] (First Embodiment) <1. Overall Configuration of the Washing and Drying Machine> FIG. 1 is a cross-sectional view showing the overall configuration of the washing and drying machine 1 according to the first embodiment. The washing and drying machine 1 is an example of a "washing machine". The washing and drying machine 1 is, for example, a drum-type washing and drying machine. The washing and drying machine 1 has, for example, a housing (outer box) 11, a door 12, an operation unit PU, a water tub 13, a drum 14, a bellows 15, a drum motor 16, a water supply valve 17, a water injection case 18, a water injection pipe 19, a drain pipe 21, a drain valve 22, a warm air supply mechanism 30, and a control device 50 (see FIG. 3).

[0009] The housing 11 has a front plate, a rear plate, a left side plate, a right side plate, a bottom plate, and a top plate, and is formed in a hollow shape. An entrance / exit 11a, which is a through-hole, is provided in the front plate of the housing 11. The door 12 is attached to the front plate of the housing 11. The door 12 closes the entrance / exit 11a so as to be openable and closable.

[0010] The operation unit PU is provided, for example, at the front upper end of the housing 11. The operation unit PU includes a plurality of buttons or a touch panel and accepts the selection of an operation course by the user. Examples of the operation course include a standard course, a time-saving course (rush course), a stylish course (careful washing course), a silent course, and the like. The time-saving course is a course that completes the washing operation in a shorter operation time compared to the standard course. The silent course is a course that suppresses noise (i.e., suppresses the vibration of the water tank 13 or the drum 14) compared to the standard course.

[0011] The water tank 13 is provided inside the housing 11. The water tank 13 is formed in a cylindrical shape with the rear surface closed. The water tank 13 is supported by an elastic support mechanism ES in a state inclined downward to the rear. The elastic modulus of the elastic support mechanism ES changes according to the temperature of the ambient environment of the washing and drying machine 1. Therefore, the vibration characteristics of the water tank 13 and the drum 14 change according to the temperature of the ambient environment of the washing and drying machine 1. For example, when the temperature of the ambient environment of the washing and drying machine 1 is high, the elastic modulus of the elastic support mechanism ES increases, and the vibration of the water tank 13 and the drum 14 increases. The front surface of the water tank 13 has an opening. In the closed state of the door 12 with respect to the entrance / exit 11a, the door 12 closes the opening on the front surface of the water tank 13 in an airtight state.

[0012] The water tank 13 has a rear end portion 13e1 and a front end portion 13e2 as both axial ends of the drum motor 16. The rear end portion 13e1 is an end portion closer to the rotation shaft 16a of the drum motor 16 among both axial ends. The rear end portion 13e1 is an example of the "first end portion". On the other hand, the front end portion 13e2 is an end portion located on the opposite side of the rear end portion 13e1 and is an end portion farther from the rotation shaft 16a of the drum motor 16 among both axial ends. The front end portion 13e2 is an example of the "second end portion".

[0013] The drum 14 is disposed within the water tank 13. The drum 14 is an accommodation chamber for accommodating clothes (laundry). The drum 14 is cylindrical and is rotatably supported within the water tank 13. The drum 14 is configured to rotate about an inclined axis (central axis CL) that extends in the front-rear direction and is inclined slightly downward from the horizontal. The drum 14 is an example of a "rotating tank". The drum 14 may be referred to as a "washing tub".

[0014] The drum 14 has a rear end portion 14e1 and a front end portion 14e2 as both axial end portions of the drum motor 16. The rear end portion 14e1 is an end portion closer to the rotation axis 16a of the drum motor 16 among both axial end portions. The rear end portion 14e1 is an example of a "first end portion". On the other hand, the front end portion 14e2 is an end portion located on the opposite side of the rear end portion 14e1 and is an end portion farther from the rotation axis 16a of the drum motor 16 among both axial end portions. The front end portion 14e2 is an example of a "second end portion".

[0015] A large number of holes 14a for water passage and ventilation are provided in the peripheral wall portion and the rear wall portion of the drum 14. A plurality of baffles 14b for stirring the laundry are provided on the inner surface of the peripheral wall portion of the drum 14. The laundry within the drum 14 is stirred by falling by gravity after moving in the circumferential direction while being caught by each baffle 14b. A circular opening through which the laundry is inserted and removed is provided in the front surface portion of the drum 14. An inlet 13a connected to the opening of the drum 14 is provided in the front surface portion of the water tank 13. The inlet 13a of the water tank 13 and the entrance / exit 11a of the housing 11 communicate with each other via a bellows 15.

[0016] The drum motor 16 is provided behind the water tank 13. The drum motor 16 constitutes a drive mechanism of the washing and drying machine 1. The drum motor 16 is, for example, a three-phase AC motor. However, the drum motor 16 may also be a DC motor with controllable speed, etc. The tip of the rotating shaft 16a of the drum motor 16 penetrates the back surface of the water tank 13 and protrudes into the water tank 13, and is connected and fixed to the central portion of the rear end portion 14e1 of the drum 14. Thereby, the drum 14 is directly rotationally driven by the drum motor 16. For example, the drum 14 is continuously rotated in the forward rotation direction (for example, the clockwise direction when viewed from the front) during the dehydration operation. For example, the drum 14 repeats forward and reverse rotations during the washing operation, rinsing operation, and drying operation. The drum motor 16 is an example of a "motor".

[0017] Here, the water tank 13 vibrates along with the vibration of the drum 14. One or more (for example, a plurality of) acceleration sensors 61 for detecting the vibration of the drum 14 by detecting the vibration of the water tank 13 are provided in the water tank 13. In the present embodiment, two acceleration sensors 61 (the first acceleration sensor 61A and the second acceleration sensor 61B) are provided in the water tank 13. The first acceleration sensor 61A is provided at the rear end portion 13e1 of the water tank 13 and detects the vibration of the rear end portion 13e1 of the water tank 13 (the vibration of the rear end portion 14e1 of the drum 14). The second acceleration sensor 61B is provided at the front end portion 13e2 of the water tank 13 and detects the vibration of the front end portion 13e2 of the water tank 13 (the vibration of the front end portion 14e2 of the drum 14). The vibration of the front end portion 14e2 of the drum 14 not supported by the rotating shaft 16a of the drum motor 16 is likely to be larger than the vibration of the rear end portion 14e1 of the drum 14 supported by the rotating shaft 16a of the drum motor 16.

[0018] The water supply valve 17 is fixed inside the housing 11. The inlet of the water supply valve 17 is connected to a faucet of a water supply through a hose (not shown). The outlet of the water supply valve 17 is switched between an open state and a closed state by a water supply valve motor 71 (see FIG. 3). The outlet of the water supply valve 17 is connected to a water injection case 18. The water injection case 18 is connected to the inside of the water tank 13 through a cylindrical water injection pipe 19. When the water supply valve 17 is opened, the water supplied from the water supply is supplied into the water tank 13.

[0019] A drain port 13b is provided at the bottom of the water tank 13. The upper end of a drain pipe 21 is connected to the drain port 13b. A drain valve 22 is provided in the drain pipe 21. The drain valve 22 is switched between an open state and a closed state by a drain valve motor 72 (see FIG. 3). When the drain valve 22 is opened, the washing water in the water tank 13 is discharged from the drain pipe 21.

[0020] An exhaust port 13c for discharging the air in the water tank 13 is provided at the upper part of the front of the water tank 13. An air supply port 13d for supplying dry air into the water tank 13 is provided at the upper part of the back surface of the water tank 13. Inside the housing 11, a warm air supply mechanism 30 for circulating and supplying warm air (heated air) in the drum 14 to perform a drying operation of laundry is provided.

[0021] The warm air supply mechanism 30 has, for example, a circulation air passage 31, a heat pump 32, and a blower fan 33. The heat pump 32 constitutes a refrigeration cycle by connecting a compressor 41, a condenser 42, an expansion device (not shown), and an evaporator 43 in a cycle by piping. The condenser 42 and the evaporator 43 are arranged in the circulation air passage 31. The heat pump 32 dehumidifies and heats the air passing through the circulation air passage 31 to generate dry air. The blower fan 33 circulates the air discharged from the exhaust port 13c in the circulation air passage 31, and supplies the air dehumidified and heated by the heat pump 32 into the drum 14 through the water tank 13 from the air supply port 13d. The heat pump 32 is an example of a "heating device" that heats the air passing through the circulation air passage 31. Note that the heating device may be a heater (such as an electric heater) instead of the heat pump 32.

[0022] <2. Electrical Circuit Configuration of Motor Drive System> FIG. 2 is a diagram showing the electrical circuit configuration for driving the drum motor 16 of the washing and drying machine 1. FIG. 2 schematically shows the drive system (motor control unit 111) of the drum motor 16. The inverter circuit 132 is configured by connecting six IGBTs (semiconductor switching elements) 133a to 133f in a three-phase bridge connection, and freewheel diodes 134a to 134f are connected between the collector and emitter of each IGBT 133a to 133f. The emitters of the IGBTs 133d, 133e, 133f on the lower arm side are connected to the ground via shunt resistors 135u, 135v, 135w. Each connection point between the emitters of the IGBTs 133d, 133e, 133f and the shunt resistors 135u, 135v, 135w is connected to the control circuit 111c via a level shift circuit 136. In the present embodiment, a combination of the shunt resistors 135u, 135v, 135w and the level shift circuit 136 constitutes an example of the current sensor 62 (see FIG. 3).

[0023] The level shift circuit 136 includes an operational amplifier or the like, generates a signal by amplifying the terminal voltage of the shunt resistors 135u, 135v, 135w, and gives a bias so that the output range of the generated signal falls on the positive side. The overcurrent comparison circuit 138 detects an overcurrent when the upper and lower arms of the inverter circuit 132 are short-circuited.

[0024] A drive power supply circuit 139 is connected to the input side of the inverter circuit 132. The drive power supply circuit 139 performs double-voltage full-wave rectification on the 100V AC power supply 140 by a full-wave rectification circuit 141 composed of a diode bridge and two capacitors 142a, 142b connected in series, and supplies a DC voltage of about 280V to the inverter circuit 132. Each phase output terminal of the inverter circuit 132 is connected to each phase winding 16u, 16v, 16w of the drum motor 16.

[0025] The control circuit 111c operates with the power supply 145 as the power source, and performs PWM (Pulse Wide Modulation) control on the six IGBTs 133a to 133f via the drive circuit 144 and the high-voltage driver circuit 146. The drive circuit 144 operates with the power supply 143 as the power source, converts the drive signal output by the control circuit 111c into a drive signal with increased voltage, and applies it to the gates of the IGBTs 133d, 133e, and 133f on the lower arm side. The high-voltage driver circuit 146 converts the output of the drive circuit 144 into a voltage higher than the double-voltage full-wave rectified voltage, and applies it to the gates of the IGBTs 133a, 133b, and 133c on the upper arm side. The output signal of the rotor position sensor 161 provided in the drum motor 16 is input to the control circuit 111c. The control circuit 111c generates a drive signal for driving the drum motor 16 based on the output signal of the rotor position sensor 161.

[0026] The control circuit 111c detects the three-phase currents Iau to Iaw flowing through the windings 16u to 16w of the drum motor 16 obtained via the level shift circuit 136, estimates the phase θ and the rotational angular velocity ω of the rotating magnetic field on the secondary side based on the detected current values, and performs direct coordinate transformation and dq (direct-quadrature) coordinate transformation on the three-phase currents Iau to Iaw to calculate the exciting current component Id and the torque current component Iq (hereinafter referred to as the "q-axis current"). The q-axis current is a current component that increases in proportion to the motor torque acting on the drum motor 16. The q-axis current is an example of the "torque current". However, the "torque current" as referred to in this specification is not limited to the q-axis current, and any current that increases according to the load of the motor may be used.

[0027] <3. Configuration of the control device> Next, the control device 50 will be described. The control device 50 is mainly composed of a computer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The control device 50 comprehensively controls the entire washing and drying machine 1, and executes a washing operation including a washing operation, a rinsing operation, and a dehydration operation by the washing and drying machine 1, and a subsequent drying operation (drying operation).

[0028] Figure 3 is a block diagram showing the functional configuration of the control device 50. In addition to the acceleration sensor 61 described above, a current sensor 62 and a temperature sensor 63 are connected to the control device 50. The current sensor 62 measures the current flowing through the drum motor 16. In FIG. 3, for convenience of explanation, the current sensor 62 and the motor control unit 111 are shown separately. However, the current sensor 62 may be included in the motor control unit 111. The temperature sensor 63 is attached to, for example, the inner surface of the housing 11 and measures the temperature of the ambient environment of the washing and drying machine 1.

[0029] The control device 50 includes, for example, a vibration detection unit 51, a weight detection unit (fabric amount detection unit) 52, a fabric quality detection unit 53, a temperature detection unit 54, a dehydration operation determination unit 55, a threshold value change unit 56, a control unit 57, a motor control unit 111, and a storage unit 59. All or part of these functional units are realized by a hardware processor such as a CPU executing a program (software). However, all or part of these functional units may be realized by hardware (including a circuit unit; circuitry) such as an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array), or discrete circuits, or may be realized by cooperation between software and hardware. The motor control unit 111 may be provided as a part of the control unit 57. The storage unit 59 is realized by one or a combination of a RAM, a ROM, and an EEPROM (Electrically Erasable Programmable ROM).

[0030] <Vibration Detection Unit> The vibration detection unit 51 detects a value related to the vibration of the water tank 13 or the drum 14 (hereinafter referred to as "vibration index value"). The vibration index value includes, for example, a vibration index value based on the magnitude of the q-axis current calculated by the control circuit 111c (hereinafter referred to as "q-axis current index value"), a vibration index value based on the magnitude of the acceleration detected by the first acceleration sensor 61A (hereinafter referred to as "first acceleration index value"), a vibration index value based on the magnitude of the acceleration detected by the second acceleration sensor 61B (hereinafter referred to as "second acceleration index value"), and a vibration index value based on a combination of the magnitude of the acceleration detected by the first acceleration sensor 61A and the magnitude of the acceleration detected by the second acceleration sensor 61B (hereinafter referred to as "combined acceleration index value"). Each of the q-axis current index value, the first acceleration index value, the second acceleration index value, and the combined acceleration index value may be the magnitude of the q-axis current or the acceleration itself, or may be a value obtained by performing a preset arithmetic process (for example, an arithmetic operation for obtaining an average value or an integral value) on the magnitude of the q-axis current or the acceleration.

[0031] <Weight detection unit> The weight detection unit 52 determines the weight (fabric amount) of the clothing by utilizing, for example, the change in the load amount of the drum motor 16 due to the weight of the clothing. The weight detection unit 52 detects the weight of the clothing based on, for example, the magnitude of the torque current flowing through the drum motor 16 (for example, the current value of the q-axis current) with the clothing accommodated in the drum 14 before water is supplied to the water tank 13 and the drum 14 is rotated by the drum motor 16.

[0032] <Fabric quality detection unit> The fabric quality detection unit 53 determines the fabric quality by utilizing, for example, the change in the load amount of the drum motor 16 due to the difference in water absorption according to the fabric quality. The fabric quality detection unit 53 determines the fabric quality by determining, for example, whether the laundry is mainly cotton-based or mainly chemical fiber-based. The fabric quality detection unit 53 detects the fabric quality by combining two indicators, which are (1) the average value (or integral value) of the q-axis current while the drum 14 is rotating at a constant speed during the washing operation, and (2) the average value of the difference between the maximum value and the minimum value of the q-axis current during one rotation of the drum 14 during the washing operation.

[0033] <Temperature detection unit> The temperature detection unit 54 receives the measurement result of the temperature sensor 63 from the temperature sensor 63. The temperature detection unit 54 detects the temperature of the ambient environment of the washing and drying machine 1 based on the measurement result of the temperature sensor 63.

[0034] <Dehydration operation determination unit> Next, the dehydration operation determination unit 55 will be described. The dehydration operation determination unit 55 makes a determination regarding how to proceed with the dehydration operation based on the vibration index value detected by the vibration detection unit 51 and a threshold value. In the present embodiment, as the way to proceed with the dehydration operation, the dehydration operation determination unit 55 determines whether to retry the dehydration operation or the number of revolutions (the maximum allowable number of revolutions) that the drum 14 reaches in the dehydration operation. The dehydration operation determination unit 55 is an example of a "determination unit".

[0035] Here, the flow of a series of washing operations will be described. FIG. 4 is a diagram showing the flow of a series of washing operations including a drying operation. The washing operation includes, for example, a "washing process", a "first dehydration process", a "shower rinse process", a "second dehydration process", a "test rinse process", a "preheat pre-dehydration process", and a "preheat final dehydration process" in this order.

[0036] The "washing process" includes detergent input, water supply, rotation of the drum 14 (washing), and drainage. The "first dehydration process" is a process that rotates the drum 14 after the "washing process" and before the "shower rinsing process" to perform a certain degree of dehydration on the clothes. The "shower rinsing process" is a rinsing process that rotates the drum 14 while simultaneously supplying and draining water (i.e., while pouring water over). The "second dehydration process" is a process that rotates the drum 14 after the "shower rinsing process" and before the "final rinsing process" to perform a certain degree of dehydration on the clothes. The "final rinsing process" is a rinsing process that rotates the drum 14 with water stored in the water tank 13. In this embodiment, the maximum rotation speed of the drum 14 in the first dehydration process and the maximum rotation speed of the drum 14 in the second dehydration process are approximately the same. Each of the first dehydration process and the second dehydration process is a dehydration process performed during a series of washing operations. The first dehydration process is an example of the "first dehydration process". The second dehydration process is another example of the "first dehydration process".

[0037] The "preheat preliminary dehydration process" is a process that rotates the drum 14 while supplying warm air to the circulation air passage 31 by the warm air supply mechanism 30 after the "final rinsing process" and before the "preheat final dehydration process" to perform preliminary dehydration on the clothes. The maximum rotation speed of the drum 14 in the preheat preliminary dehydration process is lower than the maximum rotation speed of the drum 14 in the first dehydration process or the second dehydration process.

[0038] The "preheat final dehydration process" is a dehydration process performed at the end of a series of washing operations. The preheat final dehydration process is a dehydration process performed immediately before the drying operation. The preheat final dehydration process is a dehydration process that rotates the drum 14 while supplying warm air to the circulation air passage 31 by the warm air supply mechanism 30 to remove as much moisture as possible from the clothes. The maximum rotation speed of the drum 14 in the preheat final dehydration process is higher than the maximum rotation speed of the drum 14 in the first dehydration process or the second dehydration process. The implementation time of the preheat final dehydration process is longer than the implementation time of the first dehydration process or the second dehydration process. The preheat final dehydration process is an example of the "second dehydration process".

[0039] Next, the relationship between the dehydration process and the threshold value corresponding to the vibration index value will be described. First, the operation regarding the dehydration process 1 will be described. Note that the operations regarding the dehydration process 2 and the preheat pre-dehydration process are basically the same as the operation regarding the dehydration process 1.

[0040] FIG. 5 is a diagram for explaining the startup operation of the dehydration process 1. In the startup of the dehydration process 1, the rotation speed of the drum 14 is increased stepwise, and the determination operation using the threshold value is performed at a plurality of rotation speeds (a plurality of speeds). For example, the control unit 57 first increases the rotation speed of the drum 14 to the first rotation speed R1, and then fixes the rotation speed of the drum 14 to the first rotation speed R1 for a certain period of time. After the state of the washing and drying machine 1 stabilizes, the dehydration operation determination unit 55 makes a first determination J1 regarding how to proceed with the dehydration operation based on the vibration index value detected by the vibration detection unit 51 and the threshold value T1 set corresponding to the first rotation speed R1.

[0041] For example, if the vibration index value exceeds the threshold value T1 in the first determination J1, the dehydration operation determination unit 55 determines that the imbalance of the clothing is outside the allowable range. "Imbalance" means an uneven load state due to the bias of the clothing in the drum 14. In this case, the control unit 57 performs a retry operation, which is a retry of the dehydration process. The retry operation is an operation of stopping the rotation of the drum 14, supplying water into the water tank 13, and rotating the drum 14 to move the clothing in an attempt to eliminate the imbalance of the clothing. When the retry operation is performed, it starts again from the beginning of the dehydration process (that is, from the first determination J1 at a low rotation speed).

[0042] On the other hand, when the vibration index value is equal to or less than the threshold value T1 in the first determination J1, the dehydration operation determination unit 55 determines that the imbalance of the clothing is within the allowable range. In this case, the control unit 57 increases the rotation speed of the drum 14 to a second rotation speed R2 that is higher than the first rotation speed R1, and then fixes the rotation speed of the drum 14 at the second rotation speed R2 for a certain period of time. After the state of the washing and drying machine 1 stabilizes, the dehydration operation determination unit 55 makes a second determination J2 regarding how to proceed with the dehydration operation based on the vibration index value detected by the vibration detection unit 51 and the threshold value T2 set corresponding to the second rotation speed R2.

[0043] The content of the second determination J2 is the same as the content of the first determination J1. That is, when the vibration index value exceeds the second threshold value T2 in the second determination J2, the dehydration operation determination unit 55 determines that the imbalance of the clothing is outside the allowable range. In this case, the control unit 57 performs a retry operation and starts the dehydration process from the beginning. On the other hand, when the vibration index value is equal to or less than the threshold value T2 in the second determination J2, the dehydration operation determination unit 55 determines that the imbalance of the clothing is within the allowable range. In this case, the control unit 57 increases the rotation speed of the drum 14 to a third rotation speed R3 that is higher than the second rotation speed R2. Then, a third determination J3 using the third threshold value T3 is performed at the third rotation speed R3. Similarly thereafter, when the vibration index value detected in the third determination J3 is equal to or less than the threshold value T3, a fourth determination J4 using the fourth threshold value T4 is performed at a fourth rotation speed R4 that is faster than the third rotation speed R3. When the vibration index value detected in the fourth determination J4 is equal to or less than the threshold value T4, a fifth determination J5 using the fifth threshold value T5 is performed at a fifth rotation speed R5 that is faster than the fourth rotation speed R4. The content of the third to fifth determinations J3 to J5 is the same as the content of the first determination J1. Here, the first to third rotation speeds R1 to R3 described above are rotation speeds that are half or less of the maximum rotation speed of the drum 14 in the dehydration process 1. That is, the first to third threshold values T1 to T3 used in the first to third determinations J1 to J3 are threshold values corresponding to rotation speeds that are half or less of the maximum rotation speed of the drum 14 in the dehydration process 1.

[0044] Note that the vibration index values used for determination in each of the first to fifth determinations J1 to J5 are not limited to one, and two or more of the q-axis current index value, the first acceleration index value, the second acceleration index value, and the combined acceleration index value may be used. In this case, for each of the first to fifth threshold values T1 to T5, two or more threshold values corresponding to the various vibration index values used are used.

[0045] In addition, one or more of the first to fifth determinations J1 to J5 (for example, the fifth determination J5) may be a determination for determining the rotational speed (the allowable maximum rotational speed) reached during the dehydration process in progress instead of determining the necessity of the retry operation. For example, the operation when the fifth determination J5 is a determination for determining the rotational speed reached is as follows.

[0046] When the vibration index value detected in the fifth determination J5 exceeds the threshold value T5, the dehydration operation determination unit 55 determines that the imbalance of the clothing is outside the allowable range. In this case, the control unit 57 stops increasing the rotational speed of the drum 14 beyond the fifth rotational speed R5. That is, the maximum rotational speed in the dehydration process 1 is fixed to the fifth rotational speed R5, which is lower than the target rotational speed RM1. On the other hand, when the vibration index value detected in the fifth determination J5 is equal to or less than the threshold value T5, the dehydration operation determination unit 55 determines that the imbalance of the clothing is within the allowable range. In this case, the control unit 57 increases the rotational speed of the drum 14 beyond the fifth rotational speed R5 to the target rotational speed RM1. In this case, the target rotational speed RM1 becomes the maximum rotational speed in the dehydration operation 1.

[0047] Next, the operation regarding the preheat final dehydration process will be described. FIG. 6 is a diagram for explaining the startup operation of the preheat final dehydration process. In the startup of the preheat final dehydration process, the dehydration operation determination unit 55 performs a determination operation using a threshold value at a plurality of rotational speeds while increasing the rotational speed of the drum 14 stepwise, similar to the startup of the dehydration process 1. In the preheat final dehydration process, similar to the dehydration process 1, the first to fifth determinations J1 to J5 are performed at the first to fifth rotational speeds R1 to R5. It is also the same in that the fifth determination J5 may be a determination for determining the rotational speed reached during the dehydration operation in progress instead of determining the necessity of the retry operation.

[0048] In the preheat final dehydration process, the dehydration operation determination unit 55 performs a sixth determination J6 using a sixth threshold value T6 at a sixth rotation speed R6 that is faster than the fifth rotation speed R5 after the fifth determination J5. When the vibration index value detected in the sixth determination J6 is equal to or less than the threshold value T6, a seventh determination J7 using a seventh threshold value T7 is then performed at a seventh rotation speed R7 that is faster than the sixth rotation speed R6. In the present embodiment, the sixth determination J6 and the seventh determination J7 are determinations for determining the reaching rotation speed during the ongoing dehydration operation (i.e., the preheat final dehydration process). That is, if it is determined by the dehydration operation determination unit 55 that the imbalance is outside the allowable range at the sixth rotation speed R6 or the seventh rotation speed R7, the control unit 57 stops increasing the rotation speed of the drum 14 and fixes the maximum rotation speed of the drum 14 in the preheat final dehydration process at the sixth rotation speed R6 or the seventh rotation speed R7. On the other hand, if it is determined by the dehydration operation determination unit 55 that the imbalance is within the allowable range at the sixth rotation speed R6 and the seventh rotation speed R7, the control unit 57 increases the rotation speed of the drum 14 beyond the seventh rotation speed R7 up to the target rotation speed RM2. In this case, the target rotation speed RM2 becomes the maximum rotation speed in the preheat final dehydration process. Note that the sixth determination J6 and the seventh determination J7 may be determinations for determining the necessity of a retry operation instead of determinations for determining the reaching rotation speed during the dehydration operation.

[0049] <Threshold value changing unit> Next, the threshold value changing unit 56 will be described. The threshold value changing unit 56 changes the threshold values T1 to T5 used in the first to fifth determinations J1 to J5 in the dehydration process 1 (or dehydration process 2) to the threshold values T1' to T5' used in the first to fifth determinations J1 to J5 in the preheat final dehydration process. Hereinafter, for the sake of distinction, the threshold values T1 to T5 used in the preheat final dehydration process are denoted as threshold values T1' to T5'. Note that the "changing of the threshold value" by the threshold value changing unit 56 is not limited to reading and using different threshold values, and may also include reading and executing different subprograms so as to use different threshold values.

[0050] In this embodiment, the threshold changing unit 56 reduces the thresholds T1 to T5 used in the dehydration process 1 to the thresholds T1' to T5' used in the preheating final dehydration process. "Reducing the threshold" means making the determination conditions stricter. That is, "reducing the threshold" means that the imbalance is determined to be outside the allowable range, and the retry operation is likely to be promoted, or the condition is such that the reaching rotational speed is likely to be fixed low.

[0051] FIG. 7 is a diagram conceptually showing an example of the change in the threshold. In this embodiment, the threshold changing unit 56 increases the ratio of reducing the plurality of thresholds T1' to T5' used in the preheating final dehydration process with respect to the plurality of thresholds T1 to T5 (the plurality of thresholds corresponding to the plurality of speeds) used in the dehydration process 1, and reduces them. That is, the determination regarding the imbalance becomes stricter for the determination at a lower speed (lower rotational speed), and the threshold is changed so that the retry operation is likely to be promoted.

[0052] For example, the threshold T1' is a value obtained by reducing the threshold T1 by 80%. The threshold T2' is a value obtained by reducing the threshold T2 by 70%. The threshold T3' is a value obtained by reducing the threshold T3 by 60%. The threshold T4' is a value obtained by reducing the threshold T4 by 40%. The threshold T5' is a value obtained by reducing the threshold T5 by 20%. In this embodiment, the changed thresholds T1' to T3' are changed so as to be less than or equal to half the size of the thresholds T1 to T3 before the change, respectively.

[0053] FIG. 8 is a diagram showing an example of the content of the threshold change amount information I1 corresponding to the example of FIG. 7. The threshold change amount information I1 is stored in the storage unit 59 as a part of the threshold information 59a. The threshold changing unit 56 acquires the values of the changed thresholds T1' to T5' by referring to the threshold change amount information I1. Note that the threshold change amount information I1 is not limited to table information, and may be information showing a conversion formula for converting the thresholds T1 to T5 into the thresholds T1' to T5', etc.

[0054] FIG. 9 is a diagram showing another example of the content of the threshold change amount information I1. In the example shown in FIG. 9, each of the thresholds T1 to T5 includes a threshold T1A to T5A corresponding to the first acceleration index value (i.e., an index value based on the magnitude of the acceleration detected by the first acceleration sensor 61A) and a threshold T1B to T5B corresponding to the second acceleration index value (i.e., an index value based on the magnitude of the acceleration detected by the second acceleration sensor 61B). Further, each of the changed thresholds T1' to T5' includes a changed threshold T1A' to T5A' corresponding to the first acceleration index value and a changed threshold T1B' to T5B' corresponding to the second acceleration index value. These thresholds are an example of a plurality of thresholds corresponding to a plurality of positions of the water tank 13 or the drum 14.

[0055] In the example shown in FIG. 9, the threshold change unit 56 reduces the plurality of thresholds T1A to T5A, T1B to T5B used in the dehydration process 1 to the plurality of thresholds T1A' to T5A', T1B' to T5B' used in the preheat final dehydration process, and increases the ratio of reduction for the thresholds (i.e., T1B' to T5B') corresponding to the positions farther from the drum motor 16. For example, the thresholds T1A', T2A', T3A', T4A', T5A' are values obtained by reducing the thresholds T1A, T2A, T3A, T4A, T5A by 80%, 70%, 60%, 40%, and 20% respectively. On the other hand, the thresholds T1B', T2B', T3B', T4B', T5B' are values obtained by reducing the thresholds T1B, T2B, T3B, T4B, T5B by 85%, 75%, 65%, 50%, and 30% respectively. Such information is stored in the threshold change amount information I1 and can be referred to by the control unit 57. Note that when the acceleration sensor 61 is provided at three or more positions in the axial direction of the drum motor 16, the plurality of thresholds corresponding to the plurality of positions of the water tank 13 or the drum 14 may be three or more thresholds.

[0056] <Control unit> Next, the control unit 57 is controlled. The control unit 57 controls the washing and drying machine 1 based on the determination result of the dehydration operation determination unit 55 and the change of the threshold value by the threshold value change unit 56. For example, when the vibration index value detected by the vibration detection unit 51 exceeds the threshold values T1 to T5 before the change or the threshold values T1' to T5' after the change, the control unit 57 performs a retry operation in the dehydration process or fixes the maximum rotation speed of the drum 14 in the dehydration process. On the other hand, when the vibration index value detected by the vibration detection unit 51 does not exceed the threshold values T1 to T5 before the change or the threshold values T1' to T5' after the change, the control unit 57 increases the rotation speed of the drum 14 to the target rotation speed RM1 or the target rotation speed RM2 in the dehydration process to perform the dehydration operation.

[0057] <4. Advantages> When an unbalanced state (unbalanced state) due to uneven distribution of clothing occurs in the drum 14, the water tank 13 swings around as the drum 14 rotates, causing vibration and noise. Here, compared with the dehydration process performed during a series of washing operations, the dehydration process performed at the end of a series of washing operations removes more water remaining in the clothing, so the rotation speed of the drum 14 is high and the rotation of the drum 14 may last for a long time. Here, since vibration and noise increase in proportion to the square of the rotation speed of the drum 14, an unbalanced state that was not a problem when the rotation speed of the drum 14 was low may become a problem when the rotation speed of the drum 14 is high. In addition, since the rotation of the drum 14 lasts for a long time in the dehydration process performed at the end of a series of washing operations, vibration and noise may continue for a long time. Furthermore, when the unbalanced state is large, the increase in the rotation speed of the drum 14 may be suppressed before reaching the target rotation speed, and the dehydration rate of the clothing may decrease.

[0058] On the one hand, in this embodiment, the washing and drying machine 1 includes a vibration detection unit 51 that determines how to proceed with the dehydration operation based on the vibration index value detected by the vibration detection unit 51 and a threshold value, and a threshold value change unit 56 that changes the threshold values T1' to T5' used in the preheat final dehydration process performed at the end of the washing operation with respect to the threshold values T1 to T5 used in the dehydration process 1. According to such a configuration, it is possible to start the preheat final dehydration process by selecting conditions different from those of the dehydration process 1. Thereby, the performance required by the user can be realized at a high level.

[0059] In this embodiment, the vibration detection unit 51 determines whether to retry the dehydration operation or the rotational speed reached by the drum 14 as how to proceed with the dehydration operation. According to such a configuration, it is possible to determine whether to retry the dehydration operation or the rotational speed reached by the drum 14 at the start of the preheat final dehydration process by selecting conditions different from those of the dehydration process 1. Thereby, it becomes easier to realize the performance required by the user at a higher level.

[0060] In this embodiment, the threshold change unit 56 reduces the thresholds T1' to T5' used in the preheat final dehydration process with respect to the thresholds T1 to T5 used in the dehydration process 1. According to such a configuration, it is possible to simultaneously achieve shortening of the washing operation time and reduction of vibration and noise. That is, in the dehydration process 1, since the maximum rotational speed of the drum 14 is low, the unbalance state is less likely to be a problem. For this reason, in the dehydration process 1, in order to reduce the retry operation as much as possible and shorten the time, it is desirable to set the threshold (relatively large threshold) for starting up in various unbalance states. On the other hand, if the preheat final dehydration process is started in the same relatively large unbalance state as the dehydration process 1, the vibration and noise will increase, and it will be difficult for the rotational speed to increase up to the target maximum rotational speed RM2. Therefore, by reducing the thresholds T1' to T5' used in the preheat final dehydration process, it is possible to carefully select a small unbalance state and start the dehydration process. As a result, it is possible to suppress the vibration and noise in the preheat final dehydration process and increase the rate of increase up to the target maximum rotational speed RM2. In addition, by carefully selecting a small unbalance state and starting the dehydration process, it is possible to reduce the number of times that a retry operation occurs after starting up to a high rotational speed and it becomes necessary to start over from the beginning. In this sense, it is also possible to shorten the time of the washing operation.

[0061] In this embodiment, the thresholds T1 to T5 that are reduced by the threshold change unit 56 include the thresholds T1 to T3 corresponding to rotational speeds that are half or less of the maximum rotational speed of the drum 14 in the dehydration process 1. According to such a configuration, by making a strict determination result even at a low rotational speed, it is possible to further reduce the number of times that a retry operation occurs after starting up to a high rotational speed and it becomes necessary to start over from the beginning. As a result, it is possible to shorten the time of the washing operation.

[0062] In the washing and drying machine 1, the unbalance on the front side of the water tank 13 (drum 14) is more likely to lead to larger vibrations compared to the unbalance on the rear side of the water tank 13 (drum 14) supported by the drum motor 16. Therefore, in this embodiment, when the threshold value changing unit 56 changes the plurality of threshold values T1 to T5 used in the dehydration process 1 to the plurality of threshold values T1' to T5' used in the preheat final dehydration process, the ratio of decreasing the threshold value corresponding to the position farther from the drum motor 16 is increased. According to such a configuration, it is possible to select the condition that the unbalance on the front side of the water tank 13 (drum 14) is small and start the preheat final dehydration process. Thereby, vibrations and noise can be further reduced.

[0063] The higher the rotational speed in the region where the retry operation occurs, the longer it takes for the rotation of the drum 14 to stop, and since it is necessary to increase the rotational speed of the drum 14 again through the determination operation in the low-speed region, the time delayed in one retry operation becomes longer. Therefore, in this embodiment, when the threshold value changing unit 56 changes the plurality of threshold values T1 to T5 used in the dehydration process 1 to the plurality of threshold values T1' to T5' used in the preheat final dehydration process, the ratio of decreasing the threshold value corresponding to the lower speed is increased. According to such a configuration, by increasing the ratio of decreasing the threshold value as the rotational speed is lower, it is possible to detect an unbalanced state that causes problems in the high-speed rotation region at an earlier stage. Thereby, the number of times of having to start over from the beginning due to the occurrence of a retry operation after starting up to a high rotational speed can be further reduced. As a result, the time for the washing operation can be shortened.

[0064] (Second Embodiment) Next, the second embodiment will be described. The second embodiment is different from the first embodiment in that the content of the threshold value change varies according to the weight of the clothing. The configuration other than that described below is the same as that of the first embodiment.

[0065] FIG. 10 is a diagram showing an example of the content of the threshold change amount information I2 of the second embodiment. In the present embodiment, the threshold change unit 56 varies the rate at which the threshold used in the preheat final dehydration process is changed with respect to the threshold used in the dehydration process 1 according to the weight of the clothing detected by the weight detection unit 52. In the example shown in FIG. 10, when the weight of the clothing is small, T1L to T5L, which are obtained by reducing the thresholds T1 to T5 used in the dehydration process 1 by 60% respectively, are used in the preheat final dehydration process. Also, when the weight of the clothing is medium, T1M to T5M, which are obtained by reducing the thresholds T1 to T5 used in the dehydration process 1 by 40% respectively, are used in the preheat final dehydration process. Further, when the weight of the clothing is large, T1H to T5H, which are obtained by reducing the thresholds T1 to T5 used in the dehydration process 1 by 20% respectively, are used in the preheat final dehydration process.

[0066] According to such a configuration, vibration and noise can be further suppressed. That is, the lighter the weight of the clothing (the fewer the clothing), the less likely the clothing is to evenly stick to the inner surface of the drum 14, and the more likely an unbalanced state is to occur. As a result, vibration and noise increase. Therefore, by reducing the threshold used in the preheat final dehydration process when the weight of the clothing is light, the preheat final dehydration process can be started under more strictly selected conditions when the weight of the clothing is light. As a result, vibration and noise in the preheat final dehydration process can be further suppressed. On the other hand, the thresholds T1 to T5 used in the dehydration process (for example, dehydration process 1) during the washing operation are set large even when the weight of the clothing is light, so that, for example, the retry operation in the dehydration process 1 can be reduced and the time delay can be decreased.

[0067] (Third Embodiment) Next, the third embodiment will be described. The third embodiment is different from the first embodiment in that the content of the threshold change varies according to the fabric quality of the clothing. The configuration other than that described below is the same as that of the first embodiment.

[0068] FIG. 11 is a diagram showing an example of the content of the threshold change amount information I3 in the third embodiment. In the present embodiment, the threshold change unit 56 varies the rate at which the threshold used in the preheat final dehydration process is changed with respect to the threshold used in the dehydration process 1 according to the fabric quality of the clothing detected by the fabric quality detection unit 53. In the example shown in FIG. 11, when it is determined that the clothing is mainly made of chemical fiber-based materials, T1F to T5F, which are obtained by reducing the thresholds T1 to T5 used in the dehydration process 1 by 30% each, are used in the preheat final dehydration process. On the other hand, when it is determined that the clothing is mainly made of cotton-based materials, T1C to T5C, which are obtained by reducing the thresholds T1 to T5 used in the dehydration process 1 by 50% each, are used in the preheat final dehydration process.

[0069] According to such a configuration, vibration and noise can be further suppressed. That is, when the clothing is mainly made of cotton-based materials that are easy to absorb water, an unbalanced state is likely to occur, and the vibration and noise increase. Therefore, by reducing the threshold used in the preheat final dehydration process when the clothing is mainly made of cotton-based materials, the preheat final dehydration process can be started under more strictly selected conditions when the clothing is mainly made of cotton-based materials. As a result, vibration and noise during the preheat final dehydration process can be further suppressed. On the other hand, the thresholds T1 to T5 used in the dehydration process (for example, dehydration process 1) during the washing operation are set large even when the clothing is mainly made of cotton-based materials, so that, for example, the retry operation in the dehydration process 1 can be reduced and the time delay can be decreased.

[0070] (Fourth Embodiment) Next, the fourth embodiment will be described. The fourth embodiment is different from the first embodiment in that the content of the threshold change varies according to the temperature of the surrounding environment. The configuration other than that described below is the same as that of the first embodiment.

[0071] FIG. 12 is a diagram showing an example of the content of the threshold change amount information I4 in the fourth embodiment. In the present embodiment, the threshold change unit 56 varies the rate at which the threshold used in the preheat final dehydration process is changed with respect to the threshold used in the dehydration process 1 according to the temperature of the surrounding environment detected by the temperature detection unit 54. In the example shown in FIG. 12, when the temperature of the surrounding environment is low, T1L' to T5L' obtained by reducing the thresholds T1 to T5 used in the dehydration process 1 by 20% each are used in the preheat final dehydration process. Further, when the temperature of the surrounding environment is medium, T1M' to T5M' obtained by reducing the thresholds T1 to T5 used in the dehydration process 1 by 40% each are used in the preheat final dehydration process. Further, when the temperature of the surrounding environment is high, T1H' to T5H' obtained by reducing the thresholds T1 to T5 used in the dehydration process 1 by 60% each are used in the preheat final dehydration process.

[0072] According to such a configuration, vibration and noise can be further suppressed. That is, the higher the temperature of the surrounding environment, the more easily the water tank 13 and the drum 14 shake, so the vibration and noise increase. Therefore, by reducing the threshold used in the preheat final dehydration process when the temperature of the surrounding environment is high, the preheat final dehydration process can be started under more strictly selected conditions when the temperature of the surrounding environment is high. As a result, vibration and noise in the preheat final dehydration process can be further suppressed. On the other hand, the thresholds T1 to T5 used in the dehydration process (for example, dehydration process 1) during the washing operation are set large even when the temperature of the surrounding environment is high, so that, for example, the retry operation in the dehydration process 1 can be reduced and the time delay can be decreased.

[0073] (Fifth Embodiment) Next, the fifth embodiment will be described. The fifth embodiment is different from the first embodiment in that the content of the threshold change differs according to the washing operation course. The configuration other than that described below is the same as that of the first embodiment.

[0074] FIG. 13 is a diagram showing an example of the content of the threshold change amount information I5 of the fifth embodiment. In the present embodiment, even if the weight of the clothes detected at the start of operation or during operation and the temperature of the surrounding environment are the same, the threshold change unit 56 changes the ratio of changing the threshold used in the preheat final dehydration process with respect to the threshold used in the dehydration process 1 according to the washing operation course selected by the user. In the example shown in FIG. 13, when the short-time course is selected, T1T to T5T obtained by increasing the thresholds T1 to T5 used in the dehydration process 1 by 50% each are used in the preheat final dehydration process. When the reservation course is selected, T1R to T5R obtained by increasing the thresholds T1 to T5 used in the dehydration process 1 by 20% each are used in the preheat final dehydration process. When the silent course is selected, T1S to T5S obtained by decreasing the thresholds T1 to T5 used in the dehydration process 1 by 50% each are used in the preheat final dehydration process.

[0075] According to such a configuration, when a course that needs to shorten time, such as the short-time course, is selected, the operation time can be shortened by increasing the ratio of reaching the target maximum rotation speed without delay due to the retry operation as much as possible. When the reservation course is selected, the washing operation needs to end on time. If the operation time varies, it has to be set as the time for finishing the operation with a margin. In this case, it is likely that the washing operation will end earlier than the scheduled time specified by the user, and the user may take out the clothes with a cold, hard, and wet feeling. Therefore, since the amount of imbalance may be reduced by drying the clothes in the preheat final dehydration process, setting the thresholds T1R to T5R used in the preheat final dehydration process larger than the thresholds T1 to T5 used in the dehydration process 1 reduces unnecessary retry operations and makes it easier to perform the operation within the specified time.

[0076] On the other hand, in the silent course, by reducing the thresholds T1S to T5S used in the preheat final dehydration process, the preheat final dehydration process starts only under the strictly selected imbalance conditions. Thereby, vibration and noise can be reduced.

[0077] The above describes several embodiments, but the embodiments are not limited to the above examples. For example, two or more of the above-described embodiments may be combined and implemented. For example, in the second to fifth embodiments, the threshold value used in the preheat final dehydration process may be changed to a smaller threshold value corresponding to a lower speed of the drum 14, similar to the first embodiment, or may be changed by setting a difference between the threshold value corresponding to the first acceleration index value and the threshold value corresponding to the second acceleration index value.

[0078] In the above-described embodiments, the change of the threshold value used in the preheat final dehydration process has been described. However, the dehydration process (second dehydration process) performed at the end of a series of washing operations is not limited to the preheat final dehydration process, and may be a normal final dehydration process without a drying operation. That is, the threshold value changing unit 56 may change the threshold value used in the normal final dehydration process with respect to the threshold value used in the dehydration process 1. For example, the maximum rotation speed of the drum 14 in the normal final dehydration process is higher than the maximum rotation speed of the drum 14 in the dehydration process 1 or the dehydration process 2, but is not limited thereto. For example, the execution time of the normal final dehydration process is longer than the execution time of the dehydration process 1 or the dehydration process 2, but is not limited thereto.

[0079] In the above-described embodiments, the case where the threshold value used in the final dehydration process is changed to be smaller than the threshold value used in the dehydration process 1 has been mainly described. However, the embodiments are not limited to such examples. For example, when the imbalance state in the final dehydration process is likely to be smaller than that in the dehydration process 1, the threshold value used in the final dehydration process may be changed to be larger than the threshold value used in the dehydration process 1. Further, the above-described embodiments are not limited to drum-type washing machines, and may be applied to front-loading washing machines in which the rotating tub is arranged horizontally.

[0080] According to at least one embodiment described above, the washing machine includes a determination unit that makes a determination regarding how to proceed with the dehydration operation based on the value detected by the vibration detection unit and a threshold value, and a threshold value change unit that changes the threshold value used in a second dehydration process performed at the end of the washing operation with respect to the threshold value used in a first dehydration process performed during a series of washing operations. With such a configuration, the performance required by the user can be realized at a high level.

[0081] Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, as well as in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0082] 1... Washing and drying machine (washing machine), 13... Water tank, 14... Drum (rotating tub), 51... Vibration detection unit, 52... Weight detection unit, 53... Fabric detection unit, 54... Temperature detection unit, 55... Dehydration operation determination unit (determination unit), 56... Threshold value change unit.

Claims

1. A water tank, A rotating tank disposed in the water tank for accommodating clothes, A motor for rotationally driving the rotating tank, A vibration detection unit for detecting a value related to the vibration of the water tank or the rotating tank, A determination unit for making a determination regarding how to proceed with the dehydration operation based on the value detected by the vibration detection unit and a threshold value, A threshold value changing unit for changing the threshold value used in a second dehydration process performed at the end of the washing operation with respect to the threshold value used in a first dehydration process performed during a series of washing operations, Comprising, The threshold value changing unit makes the threshold value used in the second dehydration process smaller than the threshold value used in the first dehydration process, A washing machine.

2. In the second dehydration process, the maximum rotational speed of the rotating tank is higher than that in the first dehydration process, The threshold value that is changed to be smaller by the threshold value changing unit includes a threshold value corresponding to a rotational speed that is half or less of the maximum rotational speed of the rotating tank in the first dehydration process, The washing machine according to Claim 1.

3. The determination unit determines, as how to proceed with the dehydration operation, whether to retry the dehydration operation or the maximum rotational speed of the rotating tank that is allowed, The washing machine according to Claim 1 or Claim 2.

4. The threshold value includes a plurality of threshold values corresponding to a plurality of positions of the water tank or the rotating tank, The threshold value changing unit increases the ratio of reducing the plurality of threshold values used in the second dehydration process with respect to the plurality of threshold values used in the first dehydration process, and reduces them so that the threshold value corresponding to the position farther from the rotation axis of the motor is smaller, The washing machine according to any one of Claims 1 to 3.

5. The threshold value includes a plurality of threshold values corresponding to a plurality of speeds of the rotating tank, The threshold value changing unit increases the ratio of reducing the plurality of threshold values used in the second dehydration process with respect to the plurality of threshold values used in the first dehydration process, and reduces them so that the threshold value corresponding to the lower speed is smaller, The washing machine according to any one of Claims 1 to 4.

6. Further comprising a weight detection unit for detecting the weight of the clothes accommodated in the rotating tank, The threshold value changing unit varies the ratio of changing the threshold value used in the second dehydration process with respect to the threshold value used in the first dehydration process according to the weight of the clothes detected by the weight detection unit, The washing machine according to any one of Claims 1 to 5.

7. Further comprising a fabric detection unit for detecting the fabric of the clothes accommodated in the rotating tank, The threshold changing unit varies the rate of changing the threshold used in the second dehydration process with respect to the threshold used in the first dehydration process according to the fabric quality of the clothing detected by the fabric quality detecting unit. The washing machine according to any one of claims 1 to 6. **Claim 8** The washing machine further includes a temperature detecting unit that detects the temperature of the ambient environment of the washing machine. The threshold changing unit varies the rate of changing the threshold used in the second dehydration process with respect to the threshold used in the first dehydration process according to the temperature of the ambient environment detected by the temperature detecting unit. The washing machine according to any one of claims 1 to 7. **Claim 9** Even when the weight of the clothing or the temperature of the ambient environment is the same, the threshold changing unit varies the rate of changing the threshold used in the second dehydration process with respect to the threshold used in the first dehydration process according to the selected operation course. The washing machine according to any one of claims 1 to 8.

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