JP5287418B2 - 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 with its axial direction inclined downward from the front side to 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 has a large number of through holes 6 communicating with the water tank 2 on its peripheral surface, and is provided with 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 stored 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. Therefore, 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.

  In addition, 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.

  The drum-type washing machine has a function of drying laundry stored in the drum 3, and the air in the water tank 2 is exhausted and dehumidified by the circulation air passage 11 to be dried by heating. Air is blown again into the water tank 2 by the blower fan 12.

  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. 9 and 10.

  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 average voltage of the power supply voltage of the motor 7 by means of phase control when the input frequency from the rotation detector 14 is small, and decreases the average voltage when the frequency increases.

  In the cloth amount detection process, while performing rotation control, the average voltage applied to the motor 7 is gradually increased inside the control circuit to shift to high speed rotation so that the clothes are uniformly attached to the inner wall of the drum 3 by centrifugal force. To. 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. 10, the rotation detection unit 14 converts the inertial rotational force of the drum 3 to gradually decrease due to the friction torque and stops it, and outputs it after converting it to a minute rotational speed.

  In FIG. 10, 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 cloth 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, when the rotational speed of the drum is detected, the magnitude of the drum rotational speed and the maximum value MAX stored in the RAM in the control circuit are compared. If the drum rotation speed is equal to or higher than the maximum value MAX, the drum rotation speed is written in the RAM as a new maximum value MAX. If the drum rotation speed is smaller than the maximum value MAX, then whether or not the difference between the drum rotation speed and the maximum value MAX is greater than or equal to a predetermined width, that is, whether or not the decrease in the drum rotation speed with respect to the maximum value MAX is greater than or equal to a predetermined value. Is determined, and it is determined that an eccentric load is generated in the drum. When it is determined that an eccentric load is generated on the drum, the rotation of the drum is stopped. As a result, it is possible to prevent the generation of large vibration and noise due to the eccentric load.
JP-A-5-168786 JP 2005-177091 A

  When using the above conventional cloth amount detection method, the inertial rotational force of the drum gradually decreases due to the friction torque, and the proportional relationship between the time until the drum stops and the cloth amount is obtained in advance by experiments, The obtained measurement value is applied to all washing machines of the same model.

  However, as can be seen from Equation (4), the proportional relationship between the time until the drum stops and the amount of cloth is not constant due to the variation in the friction torque Tb of the drum rotation shaft, and the numerical value varies depending on each washing machine. Have For this reason, there is a problem that the conventional cloth amount detection method has variations and the detection accuracy is limited.

  Further, in the conventional cloth amount detection method, the rotation of the drum is temporarily raised regardless of the state of the clothes, so that the laundry stored in the drum 3 is affected by the bias (unbalance distribution), and the washing tub. Vibrates greatly, and the washing tub collides with the washing machine main body and makes an abnormal sound.

  Furthermore, in the conventional eccentric load detection method, the operation of decelerating and stopping the rotation speed of the drum in the cloth amount detection is not taken into account, and when the drum is decelerated and stopped, the eccentric load is erroneously detected to rotate the drum. , And the detection accuracy of the cloth amount detection is greatly impaired.

  Accordingly, the present invention solves the above-described conventional problems, and can detect the amount of laundry put into the drum, that is, the amount of cloth, with a simple configuration and with high accuracy, while suppressing variations in the friction torque of the drum rotation shaft. It is an object of the present invention to provide a washing machine having a quantity detection means and a washing machine having a stable cloth quantity detection means that eliminates the influence of unevenness of the 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 tank elastically supported in the washing machine body, a pulley attached to the rotation center shaft and disposed outside the water tank, a motor for driving the drum via the pulley and the belt, A rotation number detection device that detects the rotation number; and a control unit that controls rotation of the motor based on a detection output of the rotation number detection device, wherein the control unit gives a command rotation number to the motor, and the motor The acceleration of the drum is accelerated by generating a constant acceleration torque in the motor by applying a voltage according to the rotation speed of the motor, and the rotation speed is increased from the predetermined rotation speed N1 to N2. Kakuka After the first detection step of measuring the degree α1, and after the first detection step, the rotation of the drum is decelerated by generating a deceleration torque in the motor, and the rotation speed is increased from a predetermined rotation speed N3 to N4. A second detecting step of measuring the angular acceleration α2 during deceleration while decreasing, and detecting the amount of cloth based on the angular acceleration α1 during acceleration and the angular acceleration α2 during deceleration, and the first detecting step During the rotation of the drum, the number of rotations of the drum is measured a plurality of times. When the number of rotations of the drum decreases and the acceleration of the decrease in the number of rotations is equal to or greater than a predetermined value , It is determined that there is a bias, and the rotational driving of the drum is stopped.

  As a result, since the amount of cloth is measured using both the speed of rising and lowering of the drum rotation, the friction torque variation of the drum rotation shaft is offset, and the influence of the variation can be suppressed. With this structure, the amount of cloth can be detected with high accuracy, and even if the distribution of the laundry in the drum becomes uneven and the vibration of the drum becomes larger than a predetermined value, it is safe. The drum can be stopped.

  In the washing machine of the present invention, in the first detection step, if the rotation speed is equal to or lower than the predetermined rotation speed even after a predetermined time has elapsed after the start of rotation acceleration of the drum, It is determined that the object is biased, and the rotational driving of the drum is stopped.

  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 body and making an abnormal sound in advance, Can be stopped.

  The washing machine of the present invention can suppress the influence of the variation in the friction torque of the drum rotation shaft of each device, and can obtain a cloth amount detection means that can be accurately detected with a simple configuration. A stable cloth amount detecting means can be obtained by eliminating the influence of bias and the like.

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 pulley attached to the rotation center shaft and disposed outside the water tank, a motor for driving the drum via the pulley and a belt, and a rotation speed detection device for detecting the rotation speed of the motor; A control unit that controls the rotation of the motor based on the detection output of the rotation number detection device, the control unit giving a command rotation number to the motor and applying a voltage according to the rotation number of the motor Thus, by generating a constant acceleration torque in the motor, the rotation of the drum is accelerated, and the angular acceleration α1 during acceleration is measured while the rotation speed increases from a predetermined rotation speed N1 to N2. Process and After the first detection step, the rotation of the drum is decelerated by generating a deceleration torque in the motor, and the angular acceleration α2 during deceleration is measured while the number of revolutions decreases from a predetermined number of revolutions N3 to N4. A second detection step that detects the amount of cloth based on the acceleration angular acceleration α1 and the deceleration angular acceleration α2, and the drum during one rotation of the drum during the first detection step; If the rotational speed of the drum is reduced and the rotational speed of the drum decreases and the acceleration of the rotational speed reduction is equal to or greater than a predetermined value, it is determined that the stored laundry is biased, and the drum is driven to rotate. Since the amount of cloth is measured by using both the rising and falling speeds of the drum rotation, the variation in the friction torque of the drum rotation shaft can be offset and the influence of the variation can be suppressed. And easy Even if the amount of cloth can be accurately detected with a single configuration, the distribution of laundry in the drum becomes non-uniform, and the vibration of the drum is greater than a predetermined value, The drum can be safely stopped.

  In a second aspect of the invention, in particular, in the first detection step, the controller of the first aspect of the invention is the case where the rotational speed is equal to or lower than the predetermined rotational speed even after a predetermined time has elapsed after the start of rotation acceleration of the drum. Determines that the contained laundry is biased and controls to stop the rotation of the drum, so that the distribution of the laundry in the drum becomes uneven and the washing tub vibrates greatly. Thus, it is possible to prevent the washing tub from colliding with the washing machine main body and generating an abnormal sound in advance, and to safely stop the drum.

  In the third aspect of the invention, in particular, when the control unit of the first or second aspect of the invention determines that the stored laundry is biased and stops the rotational driving of the drum, the cloth amount is detected as a predetermined amount. By controlling to set the determination value, even when the stored laundry is biased and the rotation of the drum is stopped, the amount of cloth can be set, and the process can proceed to the next step.

  According to a fourth aspect of the present invention, in particular, by applying a predetermined DC voltage to the motor, the control unit according to the first to third aspects causes the deceleration torque to change within a predetermined range at least in the second detection step. By controlling in this way, it becomes possible to accurately detect the amount of cloth without the need to consider the influence of fluctuations in the deceleration torque in a complicated manner.

  In the fifth invention, particularly in the first to fourth inventions, the first detection step and the second detection step are performed at a resonance rotational speed or less, so that the cloth is not affected by the vibration of the drum due to the resonance. Since the amount is detected, the amount of cloth can be detected with high accuracy.

  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 shows a schematic structure of a drum-type washing machine according to the first embodiment of the present invention. FIG. 2 shows a schematic configuration of a control device that controls 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. The basic operation as a washing machine is the same as the conventional example.

  In the control device shown in FIG. 2, the AC power of the commercial power supply 20 is rectified by the rectifier 21 and the inverter circuit 24 uses the DC power smoothed by the smoothing circuit including the choke coil 22 and the smoothing capacitor 23 as the driving power. 7 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, the blower fan 12, and the heater 29 is controlled.

The motor 7 includes a stator having three-phase windings 7a, 7b, and 7c and a rotor having three-phase windings 8a, 8b, and 8c, and is configured as a three-phase induction motor provided with a motor rotation speed detecting means 30. The rotation is controlled by the PWM control inverter circuit 24 configured by the switching elements 24a to 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 characteristics of 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 end of the first detection step, the rotation speed of the drum 3 is changed from acceleration to deceleration, and then a deceleration torque T2 is generated by the motor 7 that has rotated by inertia, and a predetermined rotation speed N3 is generated during the time t2. The second detection step is performed in which the rotational speed is decreased by ΔN2 to reach a predetermined rotational speed N4.

  Here, the operation state of the first detection process will be considered.

  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, considering the second detection step, Equation (7) and Equation (8) are obtained when the angular acceleration in the second detection step is α2.

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 the operation of detecting the amount of cloth when the laundry is biased. During the cloth amount detection, when increasing the rotation speed of the drum 3 that is the first detection step, the rotation control of the drum 3 is stopped according to the change in the rotation speed accompanying the increase in the rotation speed. ing. As shown in FIG. 5, when the laundry is biased, the rotation speed of the drum 3 does not increase uniformly, but increases while repeating vertical movement. 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 for avoiding such a situation is performed. In other words, when the rotation speed of the drum 3 is being accelerated and the rotation speed of the drum 3 decreases and the acceleration of the decrease in the rotation speed is equal to or greater than a predetermined value, the rotation control of the drum 3 is controlled to stop. . As for the detection timing of the rotation number of the drum 3, for example, the rotation number is measured eight times during one rotation, that is, every 45 degrees of rotation angle of the drum 3, and the acceleration of decrease in the rotation number is obtained. The measurement of the number of revolutions is not limited to the number of measurements described above, and there is no problem as long as the speed unevenness can be measured during one revolution.

  As shown in FIG. 5, during the first detection step during the cloth amount detection, it can be seen that the rotational speed is decreased at the time point a2. Further, at the time point a3, the rotational speed has decreased, and the acceleration of the rotational speed decrease in that case is calculated. If the value is greater than or equal to a predetermined value, the rotational driving of 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 as a table.

  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 voltage and a predetermined command rotational speed from the predetermined rotational speed N <b> 1. Control is performed to increase the rotational speed so that the rotational speed reaches a predetermined rotational speed N2 increased by ΔN1 (step S2). Here, the rotational speed n of the drum is detected (step S3), and it is determined whether or not the detected rotational speed n is higher than the previously detected drum rotational speed n-1 (step S4). If it has increased, when the drum 3 reaches the rotational speed N2 (step S5), the time t1 required for the rotational speed to increase by ΔN1 is calculated (step S6).

  On the other hand, when the detected rotational speed n is decreased as compared with the previously detected drum rotational speed n-1, the rotational speed reaches a predetermined rotational speed N2 increased by ΔN1 in the same manner as in step S2. Control is performed (step S13). Next, the drum rotation speed n + 1 is detected (step S14), and it is determined whether the rotation speed is increased compared with the rotation speed n (step S15). If it has increased, the process proceeds to step S5 to determine whether the drum 3 has reached the rotational speed N2. Hereinafter, the above determination is repeated. If the drum rotational speed n + 1 is decreased as compared with the rotational speed n, the time t3 required to decrease the rotational speed Δn, which is the difference between the drum rotational speeds n + 1 and n, is calculated (step S3). S16), α3, which is an acceleration for decreasing the drum rotation speed, is calculated (step S17), and it is determined whether α3 is equal to or greater than a predetermined value (step S18). If it is determined that α3 is equal to or greater than the predetermined value, it is determined that the stored laundry is biased, and the rotational driving of the drum is stopped (step S19). When the drum rotation driving is stopped during the cloth amount detection, a predetermined determination is made as the cloth amount detection (step S20). This is because the amount of laundry that is most likely to generate large vibrations and noise due to the eccentric load (for example, half of the rated capacity) is biased in the laundry, and the fabric is rotated during cloth amount detection. Even when is stopped, it is possible to set the amount of cloth and proceed to the next process. If it is determined in step S18 that α3 is smaller than the predetermined value, the process returns to step S13 and the above determination is repeated.

  Next, a decrease in the rotational speed of the motor 7 is started (step S7). A deceleration torque T2 is applied to reduce the rotational speed (step S8), and when the drum 3 reaches a predetermined rotational speed N4 from which the rotational speed has decreased by ΔN2 from the predetermined rotational speed N3 (step S9), the rotational speed is increased. The required time t2 required to descend by ΔN2 is calculated (step S10).

  Next, the angular acceleration α1 of the first detection step and the angular acceleration α2 of the second detection step are calculated from ΔN1, t1, ΔN2, and t2 based on the equations (5) and (7), and the difference α1 between the two angular accelerations is calculated. -Α2 is obtained (step S11), and the cloth amount is obtained from the relationship between the determination value measured in advance and the cloth amount based on the equation (9) (step S12).

  In order to accurately detect the amount of cloth using Expression (9), it is desirable to perform control so that variations in the acceleration torque T1 and the deceleration torque T2 of the motor 7 are reduced.

  The output torque characteristics of the induction motor are as shown in FIG. 7, and the acceleration torque T1 changes according to the difference (slip) between the command frequency and the actual rotational speed.

  In this case, the output torque in the detection process can be made constant by controlling the applied voltage in accordance with the rotation speed of the motor 7 so that the acceleration torque T1 is constant at least in the first detection section. Therefore, a highly accurate detection result can be obtained.

  Further, the vibration of the washing tub is greatest at the resonance frequency inherent to the vibration system including the washing tub. The vibration caused by the poor balance of the laundry is also the largest at this resonance frequency. Therefore, the resonance frequency is grasped at the time of design, and the first detection step and the second detection step are performed below the resonance frequency. By doing so, it is possible to avoid an increase in vibration.

  In the cloth amount detection of the washing machine configured as described above, the cloth amount is measured using the angular accelerations of both the drum rotation rise (first detection) and the descent speed (second detection). Therefore, the variation in the friction torque of the drum rotation shaft is canceled out, and the influence of the variation is suppressed, so that highly accurate detection is possible.

  Also, by detecting the decrease in the drum rotation speed when the drum rotation speed is increased during the cloth amount detection, the laundry tub vibrates greatly and collides with the washing machine body due to the poor balance of the laundry. It is possible to avoid the situation, determine the cloth amount determined in advance, and proceed to the next process.

(Embodiment 2)
FIG. 8 is a diagram illustrating a control method of the washing machine 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 number of rotations of the drum 3 is increased in order to detect the amount of cloth, a time limit is provided, and the number of rotations of the drum 3 is not more than a predetermined value even after a predetermined time has elapsed. In this case, a control for stopping the rotational drive of the drum 3 is provided.

  FIG. 8 shows how the rotational speed of the drum 3 increases with time. The horizontal axis represents the elapsed time when the motor 7 is driven, a predetermined voltage is applied, a predetermined command rotational speed is given, and the rotational speed of the drum 3 is increased, and the vertical axis is the rotational speed of the drum 3. .

For example, when clothes wet with water are put into the drum 3 and the laundry is biased, the output torque of the motor 7 is insufficient, and a predetermined time t4 has elapsed after the start of the first detection process. The rotational speed N6 of the drum 3 becomes smaller than a predetermined value N5. That is, if the rotation speed N6 of the drum 3 is smaller than the predetermined value N5 even after the predetermined time t4 has elapsed after the start of the first detection process, it is determined that the laundry put in the drum 3 is biased. be able to. The predetermined value N5 is a value obtained when the number of revolutions of the drum after a predetermined time t4 has elapsed after the first detection step has been measured in an experiment in the rated capacity of the washing machine, and the laundry is not biased. Any value that does not stop rotation by mistake may be used.

  In this case, if the rotation speed is not N5 or more after the predetermined first predetermined time t4 has elapsed from the start of rotation of the drum 3, the rotation driving of the drum 3 is stopped and the process proceeds to the next step. In this case, the determination value of the amount of cloth is set to the amount of clothes of the laundry that is most likely to generate large vibrations and noises due to the eccentric load (for example, half of the rated capacity). Even when the rotational drive is stopped during the cloth amount detection, it is possible to set the cloth amount and proceed to the next process.

  As described above, in the second embodiment, when the drum rotation speed is less than the predetermined value when the first predetermined time has elapsed from the start of the drum cloth amount detection, that is, the first detection process starts, By controlling to stop the rotation of the cloth, even when the laundry is biased, the cloth amount detection process can be completed and the process can proceed to the next process.

  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.

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 Output torque characteristics of the induction motor The figure which shows the control method of the drum type washing machine 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

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 (5)

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 rotatably enclosing the drum and elastically supported in a washing machine body; and the rotation A pulley attached to a central shaft and disposed outside the water tank, a motor for driving the drum via the pulley and belt, a rotation speed detection device for detecting the rotation speed of the motor, and the rotation speed detection device A control unit that controls the rotation of the motor based on the detection output of the motor, and the control unit gives a command rotation number to the motor and applies a voltage according to the rotation number of the motor to apply a constant to the motor. A first detecting step of accelerating the rotation of the drum by generating the acceleration torque and measuring the acceleration angular acceleration α1 while the rotation speed increases from a predetermined rotation speed N1 to N2, Detector After that, a second detection step of measuring the deceleration angular acceleration α2 while reducing the rotation speed of the drum by generating a deceleration torque in the motor and reducing the rotation speed from a predetermined rotation speed N3 to N4. And detecting a cloth amount based on the acceleration angular acceleration α1 and the deceleration angular acceleration α2, and a plurality of rotation speeds of the drum during one rotation of the drum during the first detection step. If the rotational speed of the drum decreases and the acceleration of the rotational speed decrease is equal to or greater than a predetermined value, it is determined that the stored laundry is biased and the rotational driving of the drum is stopped. Features a washing machine. In the first detection step, when the rotation speed is equal to or lower than the predetermined rotation speed even after a predetermined time has elapsed after the start of acceleration of rotation of the drum, the stored laundry is biased. The washing machine according to claim 1, wherein the rotation driving of the drum is stopped. The control unit determines that the stored laundry is biased, and sets the predetermined determination value as the detection of the amount of cloth when rotation of the drum is stopped. Or the washing machine of 2. The control unit according to any one of claims 1 to 3, wherein the control unit controls the deceleration torque to change within a predetermined range by applying a predetermined DC voltage to the motor, at least in the second detection step. The washing machine as described in. The washing machine according to any one of claims 1 to 4, wherein the first detection step and the second detection step are performed at a resonance frequency or lower.