JP6326634B2 - Washing machine - Google Patents

Description

  The present invention relates to a washing machine having a cloth amount sensor for detecting a cloth amount that is the amount of laundry put in a drum.

  An example of the structure of the drum type washing machine is shown in FIG. In the washing machine main body 1, a water tank 2 is supported in a suspended state by a suspension structure (not shown) having a vibration isolation structure. In the water tank 2, a drum 3 formed in a bottomed cylindrical shape is rotatably supported by inclining the axial direction of the drum 3 downward from the front side toward the back side. On the front side of the aquarium 2 is formed a clothing doorway 4 leading to the opening end of the drum 3, and by opening and closing the door 5 that closes the opening provided in the upward inclined surface on the front side of the washing machine body 1 so as to be openable and closable. The laundry can be taken in and out of the drum 3 through the clothing entrance 4.

  The drum 3 is formed with a large number of through holes 6 communicating with the water tank 2 on the peripheral surface, and provided with a plurality of stirring protrusions (not shown) for stirring clothes at a plurality of positions on the inner peripheral surface. The drum 3 is rotationally driven in the forward and reverse directions by a motor 7 attached to the back side of the water tank 2. In addition, a water injection pipe 8 and a drain pipe 9 are connected to the water tank 2 to perform water injection and drainage into the water tank 2 by controlling a water injection valve and a water discharge valve (not shown).

  When the door 5 is opened, laundry and detergent are put into the drum 3, and the operation is started by an operation on the operation panel 10 provided on the front surface of the washing machine body 1, for example, a water injection conduit is provided in the water tank 2. A predetermined amount of water is injected from 8 and the drum 3 is rotationally driven by the motor 7 to start the washing process. By the rotation of the drum 3, the laundry accommodated in the drum 3 is lifted in the rotation direction by the stirring protrusion provided on the inner peripheral wall of the drum 3, and the stirring operation of dropping from the lifted appropriate height position is repeated. The laundry has the effect of tapping and washing.

  After the required washing time, the dirty washing liquid is discharged from the drain pipe 9 and the washing liquid contained in the laundry is dehydrated by a dehydrating operation of rotating the drum 3 at a high speed. The rinsing process is performed by pouring water from 8. Also in this rinsing step, the laundry housed in the drum 3 is repeatedly washed with a stirring operation in which the laundry is lifted and dropped by the stirring protrusions by the rotation of the drum 3 to perform rinsing.

  On the back surface of the motor 7, a rotation detection unit 14 including a position detection element that detects the position of the rotor (rotor) of the motor is provided in order to detect the rotation state.

  In the drum-type washing machine having the above-described configuration, a function of detecting the amount of clothes such as clothes put in the drum 3 and automatically determining the washing time according to the amount of cloth is added. Is generally (see, for example, Patent Document 1). An example of a method for detecting the amount of cloth will be described below with reference to FIGS. 8 and 9.

  The cloth amount is detected by a control circuit (not shown) having a function of controlling the motor 7 for driving the drum 3 to rotate.

When washing is started, first, the control circuit starts the motor 7 and a detection output is input from the rotation detection unit 14. The detection frequency of the rotation detector 14 changes linearly in proportion to the rotation of the motor 7. That is, the control circuit increases the motor torque of the motor 7 when the input frequency from the rotation detector 14 is small, and decreases the motor torque when the frequency increases.

  In the cloth amount detection process, while performing rotation control, the torque of the motor 7 is gradually increased inside the control circuit to shift to high speed rotation so that the clothes are evenly adhered to the inner wall of the drum 3 by centrifugal force. In this state, the rotation of the motor 7 is stopped after continuing the rotation for a predetermined time. Thereby, the inertial rotation of the drum 3 is in a state where the motor 7 is rotated. At this time, as shown in the diagram of FIG. 9, the rotation detection unit 14 converts the inertial rotational force of the drum 3 to gradually decrease due to the friction torque and stops the rotation, and outputs the result.

  In FIG. 9, the horizontal axis indicates time, and the vertical axis indicates the number of rotations of the drive motor (motor). The time from the energization stop point E to the stop of the drum 3 is long when the amount of cloth is large, and the amount of cloth is When there are few, it is short. The cloth amount is detected by utilizing the fact that the difference in time required for the stop is proportional to the cloth amount.

  Here, when the weight of the cloth is m, the average radius of the cloth distributed on the inner periphery of the drum 3 is r, and the inertia moment of the drum 3 or the motor 7 is Jd, the inertia moment J of the rotating system including the cloth is expressed by the equation (1 ).

J = Jd + mr ² (1)
Further, assuming that the generated torque of the motor 7 is T, the friction torque of the drum and the rotating shaft is Tb, and the angular acceleration of the drum 3 is α, these relationships are expressed by Expression (2).

T = Jα + Tb (2)
Since the angular acceleration α is expressed by the equation (3) as a function of the angular velocity ω and the time t, as shown in the equation (4), if the average radius r of the cloth is constant, the rotation depends on the weight m of the cloth. The number or angular velocity ω changes.

α = dω / dt (3)
dω / dt = (T−Tb) / (Jd + mr ² ) (4)
From the above equation (4), it can be seen that dω / dt, that is, the change in the rotational speed, is inversely proportional to the fabric amount m.

  That is, the cloth amount can be known by stopping the energization of the motor 7 to inertially rotate the drum 3 and measuring the change in the rotational speed in a certain time interval until the drum 3 stops.

  In addition, a drum-type washing machine is provided that can immediately detect an eccentric load when an eccentric load due to the uneven distribution of laundry occurs suddenly (see, for example, Patent Document 2).

  A method for detecting the uneven load of the laundry will be described below.

  If an eccentric load suddenly occurs while increasing the rotation speed of the drum, the rotation speed of the drum increases as the eccentric load moves from the lowest position to the highest position as the drum rotates. Decrease. Focusing on this, when the drum rotation speed decreases by a certain width or more, it is determined that an eccentric load is generated on the drum, and the drum rotation is stopped.

Specifically, the number of rotations of the drum is detected while the rotation of the drum is being accelerated. For example, the rotation speed of the drum is detected eight times during one rotation, that is, every 45 degrees of the drum rotation angle, and the rotation speed is measured to obtain the acceleration of the decrease in the rotation speed. If the value is equal to or greater than a predetermined value, the drum rotational drive is stopped. As a result, it is possible to prevent the generation of large vibrations and noise due to the eccentric load.

JP-A-5-168786 JP 2010-227312 A

  In the above-described conventional cloth amount detection method, the drum rotation speed is increased unless the drum rotation speed is reduced regardless of the state of the clothes. Therefore, the laundry stored in the drum 3 is biased (unbalanced). Due to the influence of the distribution, the washing tub vibrates greatly, and the washing tub collides with the washing machine main body and sometimes makes an abnormal sound.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described conventional problems, and to provide a washing machine having a stable cloth amount detecting means that eliminates the influence of unevenness of laundry.

In order to solve the above-described conventional problems, a washing machine of the present invention includes a drum having a rotation center axis in a horizontal direction or an inclination direction and accommodating a laundry and rotating, and the drum being rotatably included. A water tub elastically supported in the washing machine body, a motor for driving the drum, a rotation speed detection device for detecting the rotation speed of the motor, and rotation of the motor based on a detection output of the rotation speed detection device A control unit for controlling the motor, and the control unit controls the motor torque according to the rotation speed of the motor, and generates a constant acceleration torque by controlling the rotation speed of the motor. After the first detection step of accelerating the rotation of the drum and measuring the acceleration angular acceleration α1 while the rotation number increases from a predetermined rotation number N1 to N2, the motor is subjected to the first detection step. Deceleration torque And a second detection step of measuring the deceleration angular acceleration α2 while the rotational speed is reduced from a predetermined rotational speed N3 to N4 by reducing the rotational speed of the drum, and the acceleration angular acceleration Based on α1 and the angular acceleration α2 during deceleration, the cloth amount is detected, and during the first detection step, an acceleration β1 in a state where the rotation angle from the starting position of the drum is 45 degrees or more and 90 degrees or less. If the difference in acceleration β2 in a state where the rotation angle from the starting position of the drum is 90 degrees or more is a predetermined value or more, it is determined that the stored laundry is biased and the rotation driving of the drum is stopped. It is a feature.

  As a result, the distribution of the laundry in the drum becomes non-uniform, the washing tub vibrates greatly, prevents the washing tub from colliding with the washing machine main body and making an abnormal sound in advance, Can be stopped.

  The washing machine of the present invention includes a washing machine having a cloth amount sensor for detecting the amount of cloth that is put into a drum, and a stable cloth amount detecting means that eliminates the influence of the bias of the laundry and the like. A washing machine having the same can be provided.

Sectional drawing which shows schematic structure of the drum type washing machine in Embodiment 1 of this invention. Circuit diagram showing the control device of the drum type washing machine The figure which shows the operation | movement of the cloth amount detection used for the drum type washing machine The figure which shows the cloth amount and acceleration difference of the cloth amount detection The figure which shows the operation | movement of the cloth amount detection used for the drum type washing machine Flow chart showing the cloth amount detection method The flowchart which shows the cloth amount detection operation | movement in Embodiment 2 of this invention. Sectional drawing which shows schematic structure of the drum type washing machine of a prior art example The figure which shows the cloth amount detection method of the drum type washing machine of a prior art example The flowchart which shows the cloth amount detection operation | movement in Embodiment 2 of this invention.

  According to a first aspect of the present invention, there is provided a drum having a central axis of rotation in a horizontal direction or an inclination direction, accommodating a laundry and performing a rotational movement, and rotatably enclosing the drum in a washing machine body. A water tank, a motor for driving the drum, a rotation speed detection device for detecting the rotation speed of the motor, and a control unit for controlling the rotation of the motor based on a detection output of the rotation speed detection device, The control unit controls the motor torque according to the rotation speed of the motor, and accelerates the rotation of the drum by generating a constant acceleration torque in the motor by controlling the command rotation speed. The first detection step of measuring the acceleration angular acceleration α1 while the rotation number increases from the rotation number N1 to N2, and the rotation of the drum by generating a deceleration torque after the first detection step. Slow down And a second detection step of measuring the deceleration angular acceleration α2 while the rotation speed decreases from the predetermined rotation speed N3 to N4, and based on the acceleration angular acceleration α1 and the deceleration angular acceleration α2, When the amount of cloth is detected and the difference between the acceleration β1 at the time of drum activation and the acceleration β2 at the time of drum rotation acceleration is greater than or equal to a predetermined value during the first detection step, the stored laundry is biased. Therefore, the rotation of the drum is stopped, so that the laundry distribution in the drum becomes uneven, the washing tub vibrates greatly, and the washing tub collides with the washing machine body. It is possible to prevent abnormal sounds in advance and stop the drum safely.

  In the second invention, in particular, in the first detection step, the control unit according to the first invention may be configured such that, after the drum is started, the acceleration β2 is greater than or equal to a predetermined value with respect to the acceleration β1. Can accurately determine that the stored laundry is biased.

According to a third aspect of the invention, in particular, the controller of the first or second aspect of the present invention is configured such that, in the first detection step, after the drum is driven to a certain angle, the acceleration β1 is acquired to obtain the stored laundry. It is possible to accurately determine if there is a bias in the object.

  According to a fourth aspect of the invention, in particular, the control unit according to the first to third aspects of the present invention changes the acceleration β2 with respect to the acceleration β1 that stops rotation of the drum according to the value of the acceleration β1 in the first detection step. It is possible to accurately determine that the stored laundry is biased.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a cross-sectional view showing a schematic structure of the drum type washing machine according to the first embodiment of the present invention, and FIG. 2 is a circuit diagram of a control device for controlling the operation of the drum type washing machine.

  In FIG. 1, the rotation of the motor 7 is transmitted via a belt 15 to a pulley 16 fixed to the rotation shaft of the drum 3. Since the basic operation as a washing machine is the same as that of the conventional example, the same reference numerals are given to the same components as those of the conventional example, and the description is omitted.

  In the control device shown in FIG. 2, the AC power of the commercial power source 20 is rectified by the rectifier 21, and the DC power smoothed by the smoothing circuit including the choke coil 22 and the smoothing capacitor 23 is used as the driving power. Is driven to rotate. Further, the rotation of the motor 7 is controlled based on the driving instruction input from the input setting unit 25 and the monitoring information of the driving state detected by each detecting means (not shown), and the water supply valve 27 is controlled by the load driving unit 26. The operation of the drain valve 28 and the blower fan 12 is controlled.

  The motor 7 includes a stator having three-phase windings 7a, 7b, and 7c and a rotor having three-phase windings, and is configured as a three-phase synchronous motor provided with motor rotation speed detection means 30, and includes switching elements 24a to 24c. The rotation is controlled by the PWM control inverter circuit 24 configured by 24f. The speed signal detected by the motor rotation speed detection means 30 is input to the control unit 31 constituted by a microcomputer. Based on this speed signal, the drive circuit 32 performs PWM control of the on / off states of the switching elements 24a to 24f, thereby controlling the energization of the three-phase windings 7a, 7b, and 7c of the stator, and rotating the rotor to the required rotational speed. Rotate with

  The control unit 31 includes a drum rotation speed detection unit 33 to which the detection output of the motor rotation number detection unit 30 is input. The drum rotation speed detector 33 calculates the rotation speed of the drum 3 based on the speed signal output from the motor rotation speed detector 30 and the ratio of the shaft of the motor 7 and the radius of the pulley 16. The detection output of the drum rotation speed detection unit 33 is supplied to the cloth amount detection unit 34, and the cloth amount is detected as described below based on the detected number of rotations.

  The cloth amount detection method in the present embodiment will be described below with reference to FIG.

  FIG. 3 is a diagram showing the operation of detecting the amount of cloth, and shows the relationship between the time required for increasing the rotation speed of the drum 3 and the time required for decreasing the rotation speed. Time and the vertical axis represent the number of rotations.

  When the cloth amount detection is started, the acceleration torque T1 is generated by the motor 7 after the elapse of a predetermined time or when the predetermined rotation speed N1 is reached, and the rotation speed is increased by ΔN1 during the time t1 to reach the predetermined rotation speed N2. A first detection process for detecting the arrival time t1 is performed. After the first detection step is completed, the rotation speed of the drum 3 is changed from acceleration to deceleration, and then the deceleration torque T2 is generated by the motor 7 that has rotated by inertia, and from the predetermined rotation speed N3 during the time t2. A second detection step is performed in which the rotational speed is decreased by ΔN2 and reaches a predetermined rotational speed N4.

  Here, the operation state of the first detection step will be described.

  From equation (3), the angular acceleration α1 in the first detection step is represented by equation (5).

α1 = ΔN1 / t1 (5)
Moreover, Formula (6) is materialized from Formula (1) and (2).

T1 = α1 (Jd + mr ² ) + Tb (6)
Similarly, the second detection step will be described. When the angular acceleration in the second detection step is α2, Equations (7) and (8) are obtained.

α2 = ΔN2 / t2 (7)
T2 = α2 (Jd + mr ² ) + Tb (8)
If the component of the friction torque Tb is eliminated from the equations (6) and (8), the equation (9) is obtained.

α1-α2 = (T1-T2) / (Jd + mr ² ) (9)
FIG. 4 is a diagram showing the relationship between the amount of cloth and the acceleration difference, the horizontal axis is the cloth amount, and the vertical axis is the acceleration difference. The above equation (9) is easily understood.

  When the average radius r, acceleration torque T1, and deceleration torque T2 in the drum inner circumference of the cloth are constant values, the equation (9) is expressed in accordance with the weight m of the cloth as shown in FIG. It shows that α2) changes.

  Here, α1 and α2 can be easily obtained by measuring the relationship between the number of rotations of the drum 3 and time as shown in the equations (5) and (7). Therefore, if only the relationship between the weight m of the cloth and the change in the angular acceleration (α1−α2) is grasped and stored as a calculation table in the cloth amount detection unit 34 of the control unit in FIG. It can be seen that the amount of cloth can be detected easily and accurately regardless of the relationship.

  Here, FIG. 5 shows an operation for detecting the amount of cloth when the laundry is biased. During the cloth amount detection, when increasing the rotation speed of the drum 3 as the first detection step, control is performed to stop the rotation drive of the drum 3 in accordance with the change in the rotation speed accompanying the increase in the rotation speed. Yes. As shown in FIG. 5, when the laundry is biased, the rotational speed of the drum 3 does not rise constantly but rises indefinitely. This is because the laundry tub vibrates due to the balance of the laundry accommodated in the drum 3. If the vibration becomes too large, the washing tub collides with the washing machine body and generates an abnormal sound.

  Here, control is performed to avoid the occurrence of a situation in which the washing tub collides with the washing machine body and generates an abnormal sound.

  That is, while the rotation of the drum 3 is being accelerated, if the acceleration β2 at the time of drum rotation acceleration is greater than or equal to a predetermined value with respect to the acceleration β1 at the time of drum activation, the rotation driving of the drum 3 is stopped. Control. The detection timing of the acceleration of the drum 3 is, for example, measured eight times during one rotation, that is, every 45 degrees of the rotation angle of the drum 3, and the acceleration is obtained from the rotation number. The measurement of the acceleration is not limited to the above measurement count, and there is no problem as long as the speed irregularity can be measured during one rotation.

  As shown in FIG. 5, the acceleration β1 from a1 to a2 is calculated during the detection process during the cloth amount detection. For example, when measuring the number of rotations eight times during one rotation after a2, the acceleration β2 is calculated every 45 degrees of the rotation angle of the drum 3, and if the difference between the value and the acceleration β1 is equal to or greater than a predetermined value, the drum 3 is stopped. The predetermined value is set based on an experiment in consideration of the allowable range of vibration, and is provided in the control unit 31.

  FIG. 6 is a flowchart showing the cloth amount detection method.

  In FIG. 6, when the cloth amount detection starts (step S <b> 1), the control unit 31 drives the motor 7 to give a predetermined motor torque and a predetermined command rotational speed from the predetermined rotational speed N <b> 1. Is controlled so as to reach a predetermined rotational speed N2 increased by ΔN1 (step S2), and the rotational speed n of the drum is detected (step S3). Here, when the rotation angle of the drum is not less than 46 degrees and not more than 90 degrees (steps S4 and S5), the acceleration β1 is calculated from the previous rotation speed n-1 (step S6).

When the rotation angle of the drum is 91 degrees or more (step S5), the acceleration β2 is calculated from the previous rotation speed n−1 (step S7). If it is determined that the calculated difference between β1 and β2 is less than the predetermined value (step S8), the time t1 required for the rotation speed to increase by ΔN1 when the drum 3 reaches the rotation speed N2 (step S9). Is calculated (step S10).

  On the other hand, if it is determined that the calculated difference between β1 and β2 is greater than or equal to a predetermined value (step S8), it is determined that the stored laundry is biased, and the drum rotational drive is stopped (step S13). Hereinafter, the above determination is repeated.

  Next, from ΔN1, t1, ΔN2, and t2, based on the angular acceleration α1 in the detection step based on the equations (5) and (7), the relationship between the determination value and the amount of cloth measured in advance is obtained from the equation (9). ) To obtain the amount of cloth (step S12).

  In this case, the command rotation speed is controlled so that the motor 7 is constant so that the acceleration torque T1 is constant in the detection section, and the motor torque is controlled according to the rotation speed of the motor 7, so that Since the output torque at can be made constant, a highly accurate detection result can be obtained.

  In the cloth amount detection of the washing machine configured as described above, the balance of the laundry is poor by comparing the difference between the acceleration when the drum rotation speed during the cloth amount detection is increasing and the acceleration at the time of drum activation. As a result, it is possible to avoid a situation in which the washing tub vibrates greatly and collides with the washing machine body.

(Embodiment 2)
FIG. 7 is a flowchart illustrating a cloth amount detection method according to the second embodiment of this invention.

  The configuration of the washing machine, the configuration of the control device, and the cloth amount detection method in the second embodiment are basically the same as those described in the first embodiment. The difference in the present embodiment is that when the stored laundry is judged to be biased, for example, when the number of rotations is measured eight times during one rotation, the rotation angle of the drum 3 is obtained every 45 degrees. The sum of the maximum acceleration of β2 and the second largest acceleration of β2 is used. The total acceleration is not limited to the total acceleration described above, and other accelerations may be used.

  In FIG. 7, steps up to step S7 are the same as those in the first embodiment, and thus description thereof is omitted. The acceleration β2 is calculated from the previous rotation speed n−1 (step S7), and the acceleration β2 is compared with the maximum acceleration β2max (step S20). When the acceleration β2 is equal to or greater than the maximum acceleration β2max, β2max is substituted for β2max−1, which is the second largest acceleration (step S22), and β2 is substituted for β2max, which is the maximum acceleration (step S23).

  If the acceleration β2 is not equal to or greater than the maximum acceleration β2max, the acceleration β2 is calculated from the previous rotation speed n-1 (step S7), and the acceleration β2 is compared with β2max-1, which is the second largest acceleration (step S21). When the acceleration β2 is equal to or larger than β2max−1 which is the second largest acceleration, the acceleration β2 is substituted into β2max−1 which is the second largest acceleration (step S24).

  When it is determined that the difference between the calculated acceleration β1 and the sum of the maximum acceleration β2max and the second largest acceleration β2max-1 is less than a predetermined value (step S25), when the drum 3 reaches the rotational speed N2. (Step S9), a required time t1 required for the rotation speed to increase by ΔN1 is calculated (Step S10).

On the other hand, if it is determined that the difference between the calculated acceleration β1 and the sum of the maximum acceleration β2max and the second largest acceleration β2max-1 is greater than or equal to a predetermined value (step S25), the stored laundry is biased. And the rotation of the drum is stopped (step S13). Hereinafter, the above determination is repeated.

  In the cloth amount detection of the washing machine configured as described above, the maximum value and the second largest value of the acceleration of the drum rotation speed during the cloth amount detection are compared with the acceleration at the time of starting the drum. It is possible to increase the accuracy of avoiding a situation in which the washing tub vibrates greatly and collides with the washing machine main body due to the poor balance.

(Embodiment 3)
FIG. 10 is a flowchart showing a cloth amount detection method according to the third embodiment of the present invention.

  Since the configuration of the washing machine, the configuration of the control device, and the cloth amount detection method in the third embodiment are basically the same as those described in the first embodiment, the components described in the first embodiment. The same parts are denoted by the same reference numerals and description thereof is omitted.

  The difference in the present embodiment is that the predetermined value to be compared with the difference between the acceleration β1 and the acceleration β2, which determines that the stored laundry is biased, is changed according to the value of the acceleration β1. The method of changing is not limited to the method of the third embodiment described in detail below, and other methods may be used.

  In FIG. 10, steps up to step S7 are the same as those in the first embodiment, and a description thereof will be omitted.

  The acceleration β2 is calculated from the previous rotation speed n−1 (step S7), and if it is determined that the quotient of the acceleration β1 and the acceleration β2 is equal to or greater than a predetermined value (step S30), it is determined that the stored laundry is biased. Then, the rotation of the drum is stopped (step S13). Hereinafter, the above determination is repeated.

  In the cloth amount detection of the washing machine configured as described above, the balance of the laundry is poor by comparing the quotient of the acceleration when the drum rotation speed during the cloth amount detection and the acceleration at the time of drum activation are compared. As a result, it is possible to increase the accuracy of avoiding a situation where the washing tub greatly vibrates and collides with the washing machine body.

  According to the present invention, it is possible to accurately detect the amount of cloth put into the drum with a simple configuration, and to perform appropriate washing time setting, detergent amount display, and appropriate time setting dehydration process. It is useful for home and commercial washing machines.

DESCRIPTION OF SYMBOLS 1 Washing machine main body 2 Water tank 3 Drum 7 Motor 15 Belt 16 Pulley 20 Commercial power supply 30 Motor rotation speed detection means 31 Control part 32 Drive circuit 33 Drum rotation speed detection part 34 Cloth amount detection part

Claims (4)

A drum having a central axis of rotation in a horizontal direction or an inclined direction and accommodating a laundry to perform a rotational movement; a water tub that rotatably includes the drum and elastically supported in a washing machine body; and the drum A rotation number detection device that detects the rotation number of the motor, and a control unit that controls the rotation of the motor based on a detection output of the rotation number detection device, wherein the control unit includes the motor The motor torque is controlled in accordance with the rotation speed of the motor, and the rotation speed of the drum is accelerated by generating a constant acceleration torque to the motor by controlling the rotation speed of the motor. After the first detection step of measuring the acceleration angular acceleration α1 while the rotational speed is increased to, and after the first detection step, to reduce the rotation of the drum by generating a deceleration torque in the motor, Predetermined A second detection step of measuring the angular acceleration α2 during deceleration while the rotational speed decreases from the rotational speed N3 to N4, and detecting the amount of cloth based on the angular acceleration α1 during acceleration and the angular acceleration α2 during deceleration In addition, during the first detection step, the acceleration β1 when the rotation angle from the drum activation position is 45 degrees or more and 90 degrees or less and the rotation angle from the drum activation position is 90 degrees or more . When the difference in acceleration β2 is greater than or equal to a predetermined value, it is determined that the stored laundry is biased, and the rotational driving of the drum is stopped. When the acceleration β2 is greater than or equal to a predetermined value with respect to the acceleration β1 after activation of the drum in the first detection step, the control unit is biased in the stored laundry. The washing machine according to claim 1, wherein the washing machine determines and stops the rotational driving of the drum. 3. The washing machine according to claim 1, wherein the control unit obtains the acceleration β <b> 1 after the drum is driven to a certain angle in the first detection step. 4. In the first detection step, the control unit determines a predetermined value for determining that the stored laundry is biased based on the value of the acceleration β1, that is, a predetermined value to be compared with a difference between the acceleration β1 and the acceleration β2. The washing machine according to any one of claims 1 to 3, wherein the washing machine is changed.

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