washing machine

Abstract

To provide a technology capable of accurately determining whether or not a belt is cut, or whether or not the belt is out of a pulley.SOLUTION: A washing machine includes: a rotary tub for storing laundry; a pulley fixed to a rotation shaft of the rotary tub; a motor for rotating the rotary tub; a belt stretched between the motor and the pulley, and for transmitting the rotation of the motor to the rotary tub via the pulley; a current sensor for detecting a current value flowing in the motor; and a control part. The control part executes a determination process for determining whether or not the belt is cut or whether or not the belt is out of the pulley based on the current value detected by the current sensor when accelerating the motor.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The technology disclosed in the present specification relates to a washing machine. [Background Art]

[0002] Patent Document 1 discloses a washing machine. The washing machine of Patent Document 1 comprises: a rotating drum; a drum pulley fixedly installed on the rotating shaft of the rotating drum; a motor; a belt that transmits the rotation of the motor to the drum pulley; a current detection means that detects a current flowing through the motor; and a control means that controls the motor with reference to a predetermined target rotation speed, performs drive control and brake control, and executes each step such as washing, rinsing, and spin-drying. The control means always calculates an induced voltage value from the output value of the current detection means while the motor is being driven. When the rotation speed becomes higher than the target rotation speed of the motor in each step by a predetermined value or more, the control means starts brake control of the motor, and determines that the belt is broken or detached from the drum pulley based on the relationship between the value of the induced voltage generated by the motor immediately before the brake control of the motor is performed and the time from the start of the brake control until the output value of the current detection means reaches substantially zero. [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Patent No. 6706738 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] In the technology of Patent Document 1, whether the belt is broken is determined based on a value obtained when decelerating the motor by brake control, so it is difficult to accurately determine whether the belt is broken. The same applies to determining whether the belt is detached from the pulley. Accordingly, the present specification provides a technology that can accurately determine whether the belt is broken, or whether the belt is detached from the pulley. [Means for solving the problem]

[0005] A washing machine disclosed herein comprises a rotating tub for holding laundry, a pulley fixed to the rotating shaft of the rotating tub, a motor for rotating the rotating tub, a belt stretched between the motor and the pulley and transmitting the rotation of the motor to the rotating tub via the pulley, a current sensor for detecting the value of the current flowing through the motor, and a control unit. The control unit performs a determination step to determine whether the belt is broken or whether the belt has come off the pulley, based on the value of the current detected by the current sensor when accelerating the motor. [Brief explanation of the drawing]

[0006] [Figure 1] A schematic diagram showing the washing machine of the example. [Figure 2] A diagram showing the screen displayed on the control panel of the embodiment. [Figure 3] A flowchart of the washing cycle process in the example. [Figure 4] A flowchart showing the steps of the washing cycle in the example. [Figure 5] Flowchart of the determination process and weight detection process in the first embodiment. [Figure 6] A graph showing the rotational speed of the motor in the first embodiment. [Figure 7] A graph showing the current values ​​of the motor in the first embodiment. [Figure 8] Flowchart of the determination process and weight detection process in the second embodiment. [Figure 9] A graph showing the motor rotation speed in the second embodiment. [Figure 10] Flowchart of the determination process and weight detection process in the third embodiment. [Figure 11] A graph showing the rotational speed of the motor in the third embodiment. [Modes for carrying out the invention]

[0007] The washing machine 2 of the embodiment will be described with reference to the drawings. As shown in Figure 1, the washing machine 2 comprises a housing 4, a water tank 10 located inside the housing 4, and a rotating drum 12 located inside the water tank 10. The washing machine 2 also includes a water supply path 60 and a drainage path 64 connected to the water tank 10.

[0008] Washing machine 2 is, for example, a slanted drum type washing machine equipped with a rotating tub 12 that is inclined to the horizontal. In a modified example, washing machine 2 may be, for example, a top-loading washing machine equipped with a pulsator that rotates in the rotating tub 12. The type of washing machine 2 is not particularly limited. In another modified example, washing machine 2 may be a washer-dryer capable of performing a drying cycle to dry the laundry.

[0009] The housing 4 is equipped with a rotatable door 6. By rotating the door 6, the opening 102 of the water tank 10 and the opening 122 of the rotating drum 12 are opened and closed. An operation panel 80 is provided on the top of the housing 4. The operation panel 80 is composed of, for example, a touch panel. The operation panel 80 can display various information about the washing machine 2. The operation panel 80 can also accept various user operations related to the washing machine 2.

[0010] As shown in Figure 2, the control panel 40 displays, for example, a screen SC1 for selecting a washing cycle. The control panel 40 also displays, for example, a start button B1 for instructing the start of a washing cycle. The screen SC1 and start button B1 shown in Figure 2 are displayed, for example, when the washing machine 2 is powered on.

[0011] The water tank 10, located inside the housing 4 shown in Figure 1, is capable of storing water. The rotating tub 12, located inside the water tank 10, is capable of holding laundry. The rotating tub 12 is positioned inside the water tank 10 in a rotatable state and is rotationally driven by a motor 20. A first pulley 22 is fixed to the rotating shaft 21 of the motor 20. A second pulley 14 is fixed to the rotating shaft 13 of the rotating tub 12. A belt 24 is stretched between the first pulley 22 and the second pulley 14 to transmit the rotation of the first pulley 22 to the second pulley 14 (in Figure 1, the belt 24 is highlighted in black for easier understanding). The belt 24 transmits the rotation of the motor 20 to the rotating tub 12 via the first pulley 22 and the second pulley 14. As the rotating tub 12 rotates, the laundry inside the tub 12 is washed.

[0012] The water supply route 60 has its upstream end connected to a water source (e.g., a water supply system) and its downstream end connected to the water tank 10. The water supply route 60 supplies water from the water source into the water tank 10. The water supply route 60 is equipped with a water supply valve 62. When the water supply valve 62 is opened, water is supplied into the water tank 10.

[0013] The drainage path 64 has its upstream end connected to the water tank 10 and its downstream end connected to a drainage destination (for example, a drain pan). The drainage path 64 discharges the water from the water tank 10 to the drainage destination. The drainage path 64 is equipped with a drain valve 66. When the drain valve 66 opens, the water in the water tank 10 is discharged to the drainage destination.

[0014] The washing machine 2 further includes a current sensor 52 that detects the current value flowing to the motor 20, and a control unit 50. The control unit 50 includes, for example, a CPU, ROM, and RAM, and performs various controls and processes based on a predetermined program. For example, the control unit 50 controls the rotation speed of the motor 20. The control unit 50 also performs predetermined processes based on the current value detected by the current sensor 52 when the motor 20 is accelerating. The controls and processes performed by the control unit 50 will be described later.

[0015] The washing machine 2 described above is capable of executing a washing operation for washing laundry accommodated in a rotating tub 12. In the washing operation, for example, a water supply step, a washing step, a drainage step, and the like are performed. Details of the washing operation will be described later.

[0016] (Washing operation process; Fig. 3) Next, the washing operation process of the embodiment will be described. The washing operation process is started, for example, when the power of the washing machine 2 is turned on. As shown in Fig. 3, in S10 of the washing operation process, a course for the washing operation is selected by a user operation on the operation panel 40. A user of the washing machine 2 operates the operation panel 40 (see Fig. 2) to select a desired course (for example, a standard course) from a plurality of courses having different operation contents. The courses for the washing operation include, for example, a standard course, a speed course, a soaking course, and the like. The operation content of each course can be set as appropriate. For example, for the standard course, the operation time is set to be longer than the operation time of the speed course.

[0017] As shown in Fig. 3, in the subsequent S12, the control unit 50 determines whether or not the start button B1 is pressed in a state where a course for the washing operation (for example, the standard course) is selected on the operation panel 40 (see Fig. 2). If the start button B1 is pressed (YES in S12), the process proceeds to S14. On the other hand, if the start button B1 is not pressed (NO in S12), the process returns to S10. In S14 after YES in S12, the control unit 50 executes the washing operation.

[0018] (Washing operation; Fig. 4) Next, the washing operation of the embodiment will be described. As shown in Fig. 4, the washing operation of the embodiment includes a determination step (S20), a weight detection step (S22), a water supply step (S24), a washing step (S26), and a drainage step (S28).

[0019] The determination step (S20) is a step in which the control unit 50 determines whether the belt 24 stretched between the first pulley 22 and the second pulley 14 is broken, or whether the belt 24 has come off the pulley (first pulley 22 or second pulley 14). The weight detection step (S22) is a step in which the control unit 50 detects the weight of the laundry contained in the rotating tub 12.

[0020] (Determination process and weight detection process of the first embodiment; Figures 5, 6, and 7) Next, the determination process and weight detection process of the first embodiment will be described in detail. Figure 5 is a flowchart of the determination process and weight detection process of the embodiment. The process shown in Figure 5 starts when the washing operation is started. In S40 of this process, the control unit 50 accelerates the motor 20 for rotating the rotating tub 12.

[0021] As shown in Figure 6, when the washing operation starts, the motor 20 initially rotates at a speed less than a predetermined first reference rotation speed R1. Subsequently, the control unit 50 accelerates the motor 20, increasing its rotation speed from a speed less than the predetermined first reference rotation speed R1 (for example, the first rotation speed X1 (for example, 70 rpm)) to a speed equal to or greater than a predetermined second reference rotation speed R2 (for example, the second rotation speed X2 (for example, 270 rpm)). The second reference rotation speed R2 is equal to or greater than the first reference rotation speed R1. The control unit 50 increases the rotation speed of the motor 20 from the first rotation speed X1 to the second rotation speed X2 in a time tx less than a predetermined reference time Tr. When the rotation speed of the motor 20 is less than the first reference rotation speed R1, the rotation speed of the rotating tub 12 is slow, so the laundry contained in the rotating tub 12 is less likely to stick to the inner surface of the rotating tub 12. On the other hand, when the rotational speed of the motor 20 is greater than or equal to the second reference rotational speed R2, the rotational speed of the rotating tub 12 is high, so the laundry contained in the rotating tub 12 is more likely to stick to the inner surface of the rotating tub 12. The first reference rotational speed R1 is, for example, 85 rpm. The second reference rotational speed R2 is, for example, 265 rpm. The reference time Tr is, for example, 1.8 seconds. The control unit 50 may increase the rotational speed of the motor 20 as shown in graph a, as shown in graph b, or as shown in graph c. The maximum value of the slope of the rotational speed graph when the motor 20 is accelerating is, for example, 50 (rpm / sec) or more.

[0022] As shown in Figure 5, in S42 following S40, the control unit 50 determines whether the current value Ix detected by the current sensor 52 when the motor 20 is accelerated in S40 is equal to or greater than a predetermined reference current value Ir. As shown in Figures 6 and 7, the control unit 50 determines whether the current value Ix detected by the current sensor 52 changes from less than the reference current value Ir to greater than or equal to the reference current value Ir while the rotational speed of the motor 20 is changed from a first rotational speed X1 to a second rotational speed X2.

[0023] If the detected current value Ix of the current sensor 52 is greater than or equal to the reference current value Ir (YES in S42), the process proceeds to S44 (see Figure 5). If the detected current value Ix of the current sensor 52 is less than the reference current value Ir (NO in S42), the process proceeds to S46 (see Figure 5).

[0024] As shown in Figure 5, in S44, after YES in S42, the control unit 50 determines that the belt 24 stretched between the first pulley 22 and the second pulley 14 is normal. The control unit 50 determines that the belt 24 is not broken and that the belt 24 has not come off the pulleys (first pulley 22 and second pulley 14). On the other hand, in S46, after NO in S42, the control unit 50 determines that the belt 24 is abnormal. The control unit 50 determines that the belt 24 is broken or that the belt 24 has come off the pulley (first pulley 22 or second pulley 14).

[0025] If the belt 24 is functioning correctly, the load required to rotate the rotating drum 12 acts on the motor 20, preventing the motor 20 from spinning freely. As a result, the load on the motor 20 increases, and the detected current value Ix of the current sensor 52 increases. On the other hand, if the belt 24 is abnormal, the load required to rotate the rotating drum 12 does not act on the motor 20. Therefore, the motor 20 spins freely, and the load on the motor 20 does not increase, so the detected current value Ix of the current sensor 52 does not increase. Thus, the control unit 50 can determine whether the belt 24 is broken or whether the belt 24 has come off the pulleys 22 and 14 based on the current value Ix detected by the current sensor 52 when accelerating the motor 20.

[0026] In S54, following S46, the control unit 50 displays information on the operation panel 40 indicating that there is a problem with the belt 24 (either the belt 24 is broken or the belt 24 has come off the pulleys 22 and 14). For example, the control unit 50 displays "The belt is broken." on the operation panel 40. After S54, the control unit 50 terminates the washing cycle.

[0027] On the other hand, if the belt 24 is functioning correctly, in S48, following S44, the control unit 50 calculates the weight of the laundry contained in the rotating tub 12. The control unit 50 calculates the weight of the laundry based on the current value Ix detected by the current sensor 52 when the motor 20 is accelerated in S40. The control unit 50 converts the detected current value Ix from the current sensor 52 into the weight of the laundry.

[0028] In the following step S50, the control unit 50 calculates the amount of water to be supplied to the rotating tub 12 during the washing operation. The control unit 50 calculates the amount of water to be supplied based on the weight of the laundry calculated in step S48 above.

[0029] In the following step S52, the control unit 50 calculates the amount of detergent to be added to the rotating tub 12 during the washing cycle. The control unit 50 calculates the amount of detergent based on the weight of the laundry calculated in step S48. Also in step S52, the control unit 50 displays the calculated amount of detergent (for example, "1 cup") on the operation panel 40. With this, the determination step and the weight detection step are completed.

[0030] As shown in Figure 4, after the determination process and the weight detection process are completed, the control unit 50 executes the water supply process (S24), the washing process (S26), and the drainage process (S28).

[0031] The water supply process (S24) is the process of supplying the amount of water calculated in S50 (see Figure 5) above into the rotating drum 12. In the water supply process (S24), the control unit 50 opens the water supply valve 62 provided in the water supply path 60. If the washing machine 2 is equipped with an automatic detergent dispenser, the control unit 50 may also execute a control in the water supply process (S24) to dispense the amount of detergent calculated in S52 (see Figure 5) above into the rotating drum 12 using the automatic dispenser.

[0032] The washing process (S26) shown in Figure 4 is the process of washing the laundry contained in the rotating tub 12. In the washing process (S26), the control unit 50 rotates the motor 20 at a predetermined rotational speed (for example, 150 rpm) to rotate the rotating tub 12. As a result, the rotating tub 12 rotates, and the laundry inside the rotating tub 12 is washed with the washing solution (a mixture of water and detergent). The predetermined rotational speed of the motor 20 in the washing process (S26) is smaller than the second rotational speed X2 of the motor 20 in the determination process (S20) (for example, 270 rpm, see Figure 6). In the determination process (S20), the control unit 50 accelerates the motor 20 to a second rotational speed X2 that is greater than or equal to the predetermined rotational speed in the washing process (S26) (see S40 in Figure 5). The control unit 50 determines whether the belt 24 is broken or whether the belt 24 has come off the pulleys 22 and 14 based on the current value Ix detected by the current sensor 52 at that time (see S42, S44, and S46 in Figure 5).

[0033] The drainage process (S28) shown in Figure 4 is the process of discharging the washing liquid (a mixture of water and detergent) from the rotating tub 12 to the outside of the rotating tub 12. In the drainage process (S28), the control unit 50 opens the drain valve 66 provided in the drainage path 64. With this, the washing operation is completed. Note that in the washing operation, a rinsing process and a spin-drying process may be performed after the drainage process (S28).

[0034] (effect) The washing machine 2 of the embodiment has been described above. As is clear from the above description, in the washing machine 2 of the embodiment, the control unit 50 performs a determination step to determine whether the belt 24 is broken or whether the belt 24 has come off the pulleys 22 and 14, based on the current value Ix detected by the current sensor 52 when accelerating the motor 20 (see S40, S42, S44, and S46 in Figure 5).

[0035] In this configuration, as the motor 20 accelerates, the load on the motor 20 increases if the belt 24 is not broken, and the current value Ix detected by the current sensor 52 increases. This makes the value for determination clearer, allowing for accurate determination of whether or not the belt 24 is broken. The same applies when determining whether or not the belt 24 has come off the pulleys 22 and 14.

[0036] Furthermore, the control unit 50 performs a determination step before executing the water supply step, which supplies water into the rotating tub 12 via the water supply path 60 (an example of a water supply means) (see S20 and S24 in Figure 4). With this configuration, the determination step can be executed before the laundry in the rotating tub 12 gets wet. As a result, even if it is determined that the belt 24 is broken, the laundry can be removed from the rotating tub 12 before it gets wet. The same applies if it is determined that the belt 24 has come off the pulleys 22 and 14.

[0037] Furthermore, the control unit 50 can execute the washing process after executing the water supply process (see Figure 4). In the determination process (S20), the control unit 50 determines whether the belt 24 is broken or whether the belt 24 has come off the pulleys 22 and 14, based on the current value Ix detected by the current sensor 52 when accelerating the motor 20 to a rotational speed higher than or equal to the rotational speed in the washing process (S26). With this configuration, by accelerating the motor 20 to a rotational speed higher than or equal to the rotational speed in the washing process, the load on the motor 20 increases, so it is possible to accurately determine whether the belt 24 is broken or not. The same applies when determining whether the belt 24 has come off the pulleys 22 and 14.

[0038] (Determination process and weight detection process of the second embodiment; Figures 8 and 9) Next, a second embodiment will be described. In the following, detailed explanations of configurations similar to those described above will be omitted. Figure 8 is a flowchart of the determination process and weight detection process of the second embodiment. As shown in Figure 8, in the second embodiment, the process of S60 is executed after S40. In S60, the control unit 50 stores in memory the information of the current value Ix detected by the current sensor 52 when the motor 20 is accelerated in S40. In the subsequent S62, the control unit 50 decelerates the motor 20 that was accelerated in S40. As shown in Figure 9, the control unit 50 reduces the rotational speed of the motor 20 to a rotational speed less than the first reference rotational speed R1 (for example, the first rotational speed X1).

[0039] In the following step S64, the control unit 50 accelerates the motor 20 again, which was decelerated in S62. The control unit 50 increases the rotational speed of the motor 20 from a rotational speed less than the first reference rotational speed R1 (for example, the first rotational speed X1) to a rotational speed greater than or equal to the second reference rotational speed R2 (for example, the second rotational speed X2). The control unit 50 increases the rotational speed of the motor 20 from the first rotational speed X1 to the second rotational speed X2 in a time tx less than the reference time Tr.

[0040] In the following S66, the control unit 50 stores in memory the information of the current value Ix detected by the current sensor 52 when the motor 20 is accelerated in S64. In the following S142, the control unit 50 determines whether the average value of the detected current value Ix stored in memory in S60 and the detected current value Ix stored in memory in S66 is greater than or equal to the reference current value Ir. If the average value of the detected current value Ix is greater than or equal to the reference current value Ir (YES in S142), the process proceeds to S44. If the average value of the detected current value Ix is less than the reference current value Ir (NO in S42), the process proceeds to S46.

[0041] As described above, in the second embodiment, the control unit 50 performs acceleration control to accelerate the motor 20 multiple times, and performs a determination step to determine whether the belt 24 is broken or whether the belt 24 has come off the pulleys 22 and 14, based on the current value Ix detected by the current sensor 52 during the multiple acceleration control.

[0042] With this configuration, it is possible to accurately determine whether or not the belt 24 is broken by making a determination based on multiple detected current values ​​Ix. The same applies to determining whether or not the belt 24 has come off the pulleys 22 and 14.

[0043] (modified version) In the second embodiment described above, acceleration control to accelerate the motor 20 was performed twice, but the configuration is not limited to this. In a modified example, the control unit 50 may perform acceleration control to accelerate the motor 20 three or more times. In this case, the control unit 50 determines whether the belt 24 is broken or not based on the average value of the detected current value Ix of the current sensor 52 during the three or more acceleration control operations. The same applies to determining whether the belt 24 has come off the pulleys 22 and 14.

[0044] (Determination process and weight detection process of the third embodiment; Figures 10 and 11) Next, a third embodiment will be described. In the following, detailed explanations of configurations similar to those described above will be omitted. Figure 10 is a flowchart of the determination process and weight detection process of the third embodiment. As shown in Figure 10, in the third embodiment, the process of S80 is executed after S40. In S40, the control unit 50 accelerates the motor 20 in the forward direction. The forward direction is, for example, the direction in which the rotation axis 21 of the motor 20 rotates clockwise. In the subsequent S80, the control unit 50 stores in memory the information of the current value Ix detected by the current sensor 52 when the motor 20 is accelerated in the forward direction in S40.

[0045] In the following step S82, the control unit 50 accelerates the motor 20 in the reverse direction. The reverse direction is, for example, the direction in which the rotation axis 21 of the motor 20 rotates counterclockwise. As shown in Figure 11, the control unit 50 increases the rotational speed of the motor 20 in the reverse direction from a rotational speed less than the first reference rotational speed R1 (for example, the first rotational speed X1) to a rotational speed greater than or equal to the second reference rotational speed R2 (for example, the second rotational speed X2). The control unit 50 increases the rotational speed of the motor 20 in the reverse direction from the first rotational speed X1 to the second rotational speed X2 in a time tx less than the reference time Tr.

[0046] In the following step S84, the control unit 50 stores in memory the current value Ix detected by the current sensor 52 when the motor 20 is accelerated in the reverse direction in step S82. In the following step S142, the control unit 50 determines whether the average value of the detected current value Ix stored in memory in step S80 and the detected current value Ix stored in memory in step S84 is greater than or equal to the reference current value Ir. If the average value of the detected current value Ix is greater than or equal to the reference current value Ir (YES in S142), the process proceeds to step S44. If the average value of the detected current value Ix is less than the reference current value Ir (NO in S42), the process proceeds to step S46.

[0047] As described above, in the third embodiment, the control unit 50 performs a first acceleration control (S40) to accelerate the motor 20 in the forward direction and a second acceleration control (S82) to accelerate the motor 20 in the reverse direction. Based on the current value Ix detected by the current sensor 52 during the first and second acceleration control, it determines whether or not the belt 24 is broken. The same applies to whether or not the belt 24 has come off the pulleys 22 and 14.

[0048] With this configuration, it is possible to accurately determine whether the belt 24 is broken or not by determining whether the belt 24 is broken based on the detected current value Ix when the motor 20 is rotating forward and the detected current value Ix when the motor 20 is rotating in reverse. The same applies to determining whether the belt 24 has come off the pulleys 22 and 14.

[0049] (modified version) In a modified version of the third embodiment, the control unit 50 may perform a first acceleration control to accelerate the motor 20 in the forward direction two or more times. Alternatively, the control unit 50 may perform a second acceleration control to accelerate the motor 20 in the reverse direction two or more times. In this case, the control unit 50 determines whether the belt 24 is broken based on the average value of the current value Ix detected by the current sensor 52 in the two or more first acceleration controls and the current value Ix detected by the current sensor 52 in the two or more second acceleration controls. The same applies to determining whether the belt 24 has come off the pulleys 22 and 14.

[0050] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives itself constitutes technical usefulness. [Explanation of symbols]

[0051] 2: Washing machine, 4: Casing, 10: Water tank, 12: Rotating drum, 14: Second pulley, 20: Motor, 22: First pulley, 24: Belt, 40: Control panel, 50: Control unit, 52: Current sensor, 60: Water supply path, 64: Drainage path, 80: Control panel

Claims

1. A rotating tub for holding laundry, A pulley fixed to the rotating shaft of the aforementioned rotating tank, A motor for rotating the aforementioned rotating tank, A belt is stretched between the motor and the pulley, and transmits the rotation of the motor to the rotating drum via the pulley. A current sensor that detects the current value flowing through the motor, A water supply means for supplying water into the rotating tank, It comprises a control unit and, The control unit, When accelerating the motor, a determination process can be performed to determine whether the belt is broken or whether the belt has come off the pulley, based on the current value detected by the current sensor. Before performing the water supply step, which involves supplying water into the rotating tank using the water supply means, the determination step is performed. A washing machine that, after performing the water supply step, can perform a washing step to wash the laundry in the rotating tub by rotating the motor at a predetermined rotational speed, and in the determination step, determines whether the belt is broken or whether the belt has come off the pulley based on the current value detected by the current sensor when the motor is accelerated to a rotational speed of a predetermined rotational speed or higher.

2. The washing machine according to claim 1, wherein the control unit performs acceleration control to accelerate the motor multiple times, and in the determination step, it determines whether the belt is broken or whether the belt has come off the pulley based on the current value detected by the current sensor during the multiple acceleration control operations.

3. The washing machine according to claim 1, wherein the control unit performs a first acceleration control to accelerate the motor in the forward direction and a second acceleration control to accelerate the motor in the reverse direction, and in the determination step, it determines whether the belt is broken or whether the belt has come off the pulley based on the current value detected by the current sensor during the first acceleration control and the second acceleration control.

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