JP2008264331A - Washing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control the effect of variability of a frictional torque of a drum rotary shaft and detect the amount of cloth inside a drum accurately with a simple structure. <P>SOLUTION: A washing machine is provided with a motor 7 for rotary driving the drum 3, a rotation number detecting section 33 which detects the rotation number of the motor, and a control section 31 which controls the rotation of the motor from the detection output of the rotation number detecting section 33. The control section is equipped with the first detecting process of measuring the time t1 for the rotation number to increase by ΔN1 by accelerating the rotation of the drum by a specified acceleration torque by the motor for detecting the amount of cloth, the switching process of conducting deceleration drive after the first detecting process, and the second detecting process of measuring the time t2 for the rotation number to decrease by ΔN2 by decelerating the rotation of the drum by a specified deceleration torque by the motor and detecting the amount of cloth from the angular acceleration torque by the motor as well as the amount of cloth from the angular acceleration α1 at the time of acceleration and the angular deceleration α2 at the time of deceleration that are provided by these processes. <P>COPYRIGHT: (C)2009,JPO&INPIT

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 body 1, a water tank 2 is supported in a suspended state by a suspension structure (not shown). A drum 3 formed in a bottomed cylindrical shape is supported in the water tank 2 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 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, 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 formed in the peripheral surface thereof that communicate with the water tank 2, and is provided with stirring protrusions (not shown) 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.

  This drum-type washing machine is provided with 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 heat and dry the air. The air is blown into the water tank 2 again. In the middle of the circulation air passage 11, a dehumidifying means such as an evaporator, a heating means such as a condenser, and a blower fan 12 serving as an air blowing means are provided. In the drying process using the circulation air passage 11, foreign matter such as lint generated from laundry such as clothes is circulated in the air circulated through the circulation air passage 11, and the eyes of the evaporator and the condenser are circulated. Since clogging, biting into the rotating part of the blower fan 12 and deposition on the inner surface of the blower fan 12 are likely to be hindered, foreign substances in the circulating air are trapped in the middle of the circulation blower path 11. A filter 13 to be removed is provided. A rotation detection unit 14 for detecting the rotation of the motor 7 is provided.

  In the drum type washing machine having the above-described configuration, the amount of laundry such as clothes put in the drum 3 is detected, and the washing time and the like are determined according to the amount of cloth. An example of a method for detecting the amount of cloth disclosed in Patent Document 1 will be described below with reference to FIG.

  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 detection unit 14 changes linearly with the rotation of the motor 7. 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 FIG. 8, the rotation detection unit 14 converts a state in which the inertial rotational force of the drum 3 gradually decreases due to the friction torque to stop, and outputs the converted value to the minute rotation number. In FIG. 8, the horizontal axis represents time, and the vertical axis represents the number of rotations of the drive motor (motor). The time from the stop of energization to the stop of the drum 3 is long when the amount of cloth is large and short when the amount of cloth is small. 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 cloth is obtained by Expression (1).

J = Jd + mr ² (1)
Further, assuming that the generated torque of the motor 7 is T, the friction torque of the drum rotation 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)
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.
JP-A-5-168786

  In the case of using the above conventional cloth amount detection method, the proportional relationship between the time until the drum's inertial rotational force gradually decreases due to the friction torque and the drum stops, and the cloth amount is obtained in advance by experiments. become. 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 and varies depending on the washing machine due to the influence of the variation in the friction torque of the drum rotation shaft. Therefore, the detection accuracy of the conventional cloth amount detection method has a limit.

  The present invention solves the above-described conventional problems, and can detect the amount of cloth fed into the drum with a simple configuration and with a simple configuration, while suppressing the influence of variation in friction torque of the drum rotation shaft. An object is to provide a washing machine having means.

  In order to solve the above-described conventional problems, the washing machine of the present invention accelerates the rotation of the drum by generating a predetermined acceleration torque in the motor and increases the rotation speed from the predetermined rotation speed N1 to N2. After the first detection step of measuring the angular acceleration α1 during acceleration and the first detection step, the rotation of the drum is decelerated by generating a predetermined deceleration torque Tc in the motor, and the predetermined rotation speed A second detection step of measuring the deceleration angular acceleration α2 while the rotational speed is reduced from N3 to N4, and the motor is decelerated to end the first detection step and switch to the second detection step. A switching step for generating torque Tb, detecting the amount of cloth based on angular acceleration α1 during acceleration and angular acceleration α2 during deceleration, Tb <0, and (absolute value of Tb) <(Tc Absolute value) It is.

  As a result, since the cloth amount is measured using both the speed of rising and lowering of the rotation of the drum, the variation of the friction torque of the drum rotation shaft can be offset, and the influence of the variation can be suppressed. Between the first detection step and the second detection step, there is a switching step in which deceleration is moderately performed with a deceleration torque Tc where Tb <0 and (absolute value of Tb) <(absolute value of Tc). Thus, since the first detection process and the second detection process can be switched smoothly, the amount of cloth can be accurately detected with a simple configuration.

  Since the washing machine of the present invention measures the amount of cloth using both the rotation speed of the drum and the speed of the descent, the variation in the friction torque of the drum rotation shaft is offset and the influence of the variation can be suppressed. In addition, since the first detection process and the second detection process can be smoothly switched, the amount of cloth can be detected with a simple configuration with high accuracy.

  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 that rotationally drives the drum, a rotation number detection unit that detects the rotation number of the motor, and a control unit that controls the rotation of the motor based on the detection output of the rotation number detection unit, The control unit accelerates the rotation of the drum by generating a predetermined acceleration torque in the motor, and measures the acceleration angular acceleration α1 while the rotation speed increases from the predetermined rotation speed N1 to N2. After the first detection step and the first detection step, the rotation of the drum is decelerated by causing the motor to generate a predetermined deceleration torque Tc, and the rotation speed decreases from a predetermined rotation speed N3 to N4. During deceleration during A second detection step for measuring the acceleration α2, and a switching step for causing the motor to generate a deceleration torque Tb in order to terminate the first detection step and switch to the second detection step, Based on the angular acceleration α1 and the deceleration angular acceleration α2, the cloth amount is detected, and when Tb <0 and (absolute value of Tb) <(absolute value of Tc), the drum rotation increases. Since the cloth amount is measured using both the descent speed and the descent speed, the variation in the friction torque of the drum rotation shaft can be offset, and the influence of the variation can be suppressed. Between the first detection step and the first detection step by including a switching step in which the deceleration torque Tc satisfies Tb <0 and (absolute value of Tb) <(absolute value of Tc). Second detector Since the switching can be smoothly performed, the amount of cloth can be accurately detected with a simple configuration.

  In particular, the second invention has a plurality of predetermined values of deceleration torque in the switching process in the first invention, and changes the deceleration torque according to the elapsed time from the start of the switching process and the rotation state of the drum. Since the first detection process and the second detection process can be switched more smoothly, the amount of cloth can be detected with a simple configuration with high accuracy.

  According to a third aspect of the invention, in particular, in the second aspect of the invention, at least the rotation of the drum is accelerated by generating a predetermined acceleration torque in the motor, and the rotational speed increases from a predetermined rotational speed N1 to N2. After the first detection step of measuring the angular acceleration α1 during acceleration and the first detection step, the rotation of the drum is decelerated by generating a predetermined deceleration torque Tb in the motor, and the predetermined rotation A second detection step of measuring the deceleration angular acceleration α2 while the number of revolutions is reduced from a number N3 to N4, and a switching step of ending the first detection step and switching to the second detection step. In the cloth amount detecting means for detecting the amount of cloth based on the acceleration angular acceleration α1 and the deceleration angular acceleration α2, when the elapsed time since the start of the cloth amount detection is t, To the motor The switching angular acceleration α3 (t) is controlled by generating the torque Td, the acceleration angular acceleration α1 at the end of the first detection process, and the switching angular acceleration α (ts) at t = ts at the start of the switching process. Is substantially the same value, and the switching angular acceleration α (te) at time t = te at the end of the switching step is substantially the same value as the deceleration angular acceleration α2 at the start of the second detection step. Since the switching between the detection step and the second detection step can be performed more smoothly, the amount of cloth can be accurately detected with a simple configuration.

  According to a fourth aspect of the invention, in particular, in any one of the first to third aspects of the invention, the control unit performs the first detection step when the elapsed time from the start of the cloth amount detection is t. And a starting step of starting the drum from a stationary state by generating an acceleration torque to the motor and increasing the rotational speed to a predetermined rotational speed Na with a starting angular acceleration αa (t). By providing the startup angular acceleration αa (t) that satisfies αa (t1)> α1 at a certain time t1, the centrifugal force generated by the acceleration that satisfies αa (ta)> α1 causes the clothing to be applied to the inner wall of the drum. Since the 1st detection process can be started in the state stuck, the state of the clothes in the 1st detection process can be stabilized, and it becomes possible to detect the amount of cloths with sufficient accuracy.

  According to a fifth aspect of the invention, in particular, in any one of the first to fourth aspects of the invention, at least during the first detection step and the second detection step, the q-axis current supplied to the motor is increased or decreased. By controlling the acceleration torque and deceleration torque of the motor, the acceleration torque and the deceleration torque are made substantially constant by making the q-axis current related to the magnet torque that is the main component of the torque in the motor constant. Because of the control, the cloth amount can be detected with high accuracy.

  According to a sixth invention, in particular, in any one of the first to fifth inventions, at least during the first detection step and the second detection step, the d-axis current supplied to the motor is substantially zero. As a result, since the generated torque in the motor is only the magnet torque, the acceleration torque and the deceleration torque are controlled only by the q-axis current, so that the control can be easily performed. It becomes possible to detect.

  In a seventh aspect of the invention, in particular, in any one of the first to sixth aspects of the invention, the control unit measures the maximum rotation speed and the minimum rotation speed of the drum in the predetermined rotation angle section in the first detection step, When the difference between the maximum rotation speed and the minimum rotation speed is equal to or greater than a predetermined value, by stopping the rotation of the drum, the distribution of the cloth in the drum becomes non-uniform, and the vibration of the drum is predetermined. Even when the value is larger than the value, the drum can be safely stopped.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be understood that the embodiments disclosed below are illustrative in all respects and are not restrictive. The technical scope of the present invention is shown not by the content disclosed in the embodiment but by the description of the scope of claims, and further includes all modifications within the meaning and scope equivalent to the scope of claims. Should be understood.

(Embodiment 1)
The schematic structure of the drum type washing machine in Embodiment 1 of the present invention is the same as that of the conventional example shown in FIG. The control device for controlling the operation of the drum type washing machine in the present embodiment has a schematic configuration as shown in FIG.

  In the control device shown in FIG. 1, AC power from a commercial power source 20 is rectified by a rectifier 21, and DC power smoothed by a smoothing circuit including a choke coil 22 and a smoothing capacitor 23 is used as drive power, and a motor is driven by an inverter circuit 24. 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 a two-pole permanent magnet, and is configured as a DC brushless motor provided with three position detection elements 30a, 30b, and 30c. The rotation is controlled by a PWM control inverter circuit 24 configured by the switching elements 24a to 24f. The rotor position detection signals detected by the position detection elements 30a, 30b, and 30c are input to the control unit 31 configured by a microcomputer. Based on this rotor position detection 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, thereby requiring the rotor. Rotate at the number of revolutions.

  The control unit 31 includes a rotation speed detection unit 33 to which detection outputs of the three position detection elements 30a, 30b, and 30c are input. The rotation speed detection unit 33 detects the cycle each time the signal state of any of the three position detection elements 30a, 30b, and 30c changes, and calculates the rotation speed of the rotor from the cycle. The detection output of the rotation speed detector 33 is supplied to the cloth amount detector 34, and the cloth amount is detected as described below based on the detected rotation speed. Since the detection output of the rotation speed detector 33 corresponds to the rotation speed of the drum 3, the rotation speed of the drum 3 is obtained from the detection output of the rotation speed detector 33 in the following description.

  The feature of the cloth amount detection method in the present embodiment will be described with reference to FIG. FIG. 2 shows the relationship between the time required for increasing the rotational speed of the drum 3 and the time required for decreasing the rotational speed. The horizontal axis represents the elapsed time from the start of the cloth amount detection, and the vertical axis represents the rotation speed. When the cloth amount detection is started, after a predetermined time elapses or the rotation speed is reached, the motor 7 generates acceleration torque Ta, and a first detection process is performed in which the rotation speed is increased by ΔN1 during time t1. After the first detection step is completed, the rotation speed of the drum 3 is changed from acceleration to deceleration, and then a deceleration torque Tb is generated by the motor 7 so that a predetermined time elapses or the drum 3 reaches a predetermined rotation speed. A switching step is performed in which the vehicle is decelerated until it reaches. When the switching step ends, a second detection step is performed in which the motor 7 generates a deceleration torque Tc, and the rotational speed is decreased by ΔN2 during time t2.

  Here, it is assumed that (absolute value of Tc) <(absolute value of Tb).

  The main purpose of this switching step is to smoothly switch between the first detection step and the second detection step, so Tb may be a constant value, but the elapsed time from the start of the switching step. Further, even if a plurality of values are changed depending on the state of the drum 3, switching can be performed more smoothly.

  In addition, the angular acceleration at the end of the first detection step and the angular acceleration at the start of the switching step is made substantially the same, and the angular acceleration at the end of the switching step and the start of the second detection step is made almost the same, thereby enabling smoother switching. It can be carried out.

  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 (3).

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)
When 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)
When the average radius r, acceleration torque T1, and deceleration torque T2 in the drum inner periphery of the cloth are constant values, the equation (9) is expressed as (α1−) according to 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, only the relationship between the fabric weight m and the change in the angular acceleration (α1−α2) is grasped and stored as a table or the like in the fabric amount detection unit 34 in FIG. 1, regardless of the change in the friction torque Tb. It can be seen that the amount of cloth can be detected easily and accurately.

  FIG. 4 is a flowchart showing the cloth amount detection method in the present embodiment. When the cloth amount detection starts (step S1), the control unit 31 drives the motor 7 to increase the rotational speed of the drum 3 from the predetermined rotational speed A by a predetermined torque, and the rotational speed increases by ΔN1. Control is performed so as to reach the predetermined rotational speed B (step S2). When the drum 3 reaches the rotational speed B (step S3), a time t1 required for the rotational speed to increase by ΔN1 is calculated (step S4).

  Next, a deceleration operation is performed with the deceleration torque Tb, and a decrease in the rotational speed of the motor 7 is started (step S5). Deceleration is started with the deceleration torque Tc after a predetermined time has elapsed after the deceleration operation is started with the deceleration torque Tb or when the drum 3 reaches a predetermined number of revolutions (step S6). When the drum 3 reaches a predetermined rotational speed D where the rotational speed has decreased by ΔN2 from the predetermined rotational speed C (step S7), a required time t2 required for the rotational speed to decrease by ΔN2 is calculated (step S7). S8). Next, from ΔN1, t1, ΔN2, and t2, the angular acceleration difference α1-α2 is obtained based on the equations (5) and (7) (step S9), and the determination value S and the amount of the cloth measured in advance are calculated. From the relationship, the cloth amount is obtained based on the equation (9) (step S10).

  In order to accurately detect the amount of cloth using Expression (9), it is desirable to control the acceleration torque T1 and the deceleration torque T2 of the motor 7 to be constant.

  Such control can be realized by controlling the voltage applied to the motor 7, but it is generally known that constant torque control of the motor is performed by vector control as shown in FIG. .

In the control block of FIG. 5, at least two-phase current out of the current supplied to the motor 7 and a rotational position signal of the motor obtained by a Hall IC or the like are detected. Using these signals, the current of the motor 7 is converted into two orthogonal currents, Iq which is a torque component and Id which is a magnetic flux component. Thereafter, the converted Iq and Id are compared with the commanded Iq ^* and Id ^* , and the appropriate control gains P and I are used to control the Iq and Id of the motor 7 to be constant. Can do.

  Here, since the torque T of the motor 7 is expressed by Expression (10), the torque T of the motor 7 can be controlled by controlling Iq and Id.

T = P (ψa · Iq + (Ld−Lq) IqId) (10)
Here, P is the number of pole pairs of the motor 7, ψa is a flux linkage by a magnet, Ld is a d-axis inductance, and Lq is a q-axis inductance.

  In particular, ψa · Iq in equation (10) represents a magnet torque and is the main component of the torque generated by the motor. Therefore, the torque of the motor 7 can be controlled by Iq. Further, when Id is not zero, if Ld or Lq changes depending on the rotation state, an error is likely to occur when calculating the torque T when calculating the variation of the torque T or the amount of cloth. That is, there is a case where the torque T does not become constant even if Iq and Id are controlled to be constant. Therefore, by setting Id to zero and controlling Iq to be constant, the torque of the motor 7 is controlled to be constant. It is desirable to reduce the amount calculation error.

  In FIG. 2, the period from the start of the drum 3 (0 second) to the start of the first detection process (the left end of the section t1) is referred to as the start process, and the start is performed as a condition of the acceleration αa (t) in this start process. If the starting angular acceleration αa (t) satisfying αa (ta)> α1 is provided at a certain time ta of the process, the start of the first detection process is started in a state where clothing is adhered to the inner wall of the drum 3. Therefore, the amount of cloth can be detected with high accuracy.

(Embodiment 2)
A washing machine according to Embodiment 2 of the present invention will be described with reference to FIG. The configuration of the washing machine, the configuration of the control device, and the cloth amount detection method in the present 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, the driving of the drum 3 is stopped according to the change in the number of rotations accompanying the increase in the number of rotations. This is the point where control is provided.

  FIG. 6A shows how the rotation speed of the drum 3 increases with time. The horizontal axis represents the elapsed time when the motor 7 is driven and the rotational speed of the drum 3 is increased by a predetermined torque, and the vertical axis is the rotational speed of the drum 3. As shown in the figure, the rotational 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.

  In the present embodiment, control for avoiding such a situation is performed. That is, the difference between the maximum rotation speed and the minimum rotation speed is detected for the rotation speed of the drum 3 in a predetermined rotation angle section while the rotation of the drum 3 is being accelerated. If the difference is greater than or equal to a predetermined value, the drum 3 is controlled to stop rotating. As the maximum rotation speed and the minimum rotation speed of the drum 3 in the predetermined rotation angle section, for example, the rotation speed is measured four times during one rotation, and the maximum rotation speed and the minimum rotation speed are obtained.

  For example, as shown in FIG. 6B, the upper limit value of the difference between the maximum rotation speed and the minimum rotation speed is set based on the experiment in correspondence with the rotation speed of the drum 3, and is provided in the control unit 31 as a table. . The upper limit value of the difference between the maximum rotation speed and the minimum rotation speed as shown in FIG. 6B may be set based on the allowable range of vibration obtained experimentally at each rotation speed of the drum 3.

  In this way, by controlling so that the difference between the maximum rotation speed and the minimum rotation speed in the predetermined rotation angle section of the drum 3 does not exceed the upper limit value, the laundry tub becomes large due to the poor balance of the laundry. It is possible to avoid a situation where it vibrates and collides with the washing machine body.

  As described above, the washing machine of the present invention can accurately detect the amount of cloth put into the drum with a simple configuration and perform a good dehydration process. Useful for the machine.

The circuit diagram which shows the control apparatus of the washing machine in Embodiment 1 of this invention The figure which shows the operation | movement of the cloth amount detection used for the washing machine The figure which shows the cloth amount and acceleration difference of the cloth amount detection of the washing machine The flowchart which shows the cloth amount detection method of the washing machine Vector control block diagram for cloth amount detection of the washing machine The figure which shows the control method of the washing machine in Embodiment 2 of this invention. Sectional drawing which shows schematic structure of the conventional drum type washing machine The figure which shows the cloth amount detection method of the conventional drum type washing machine

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Washing machine main body 2 Water tank 3 Drum 4 Clothes entrance / exit 5 Door 7 Motor 7a, 7b, 7c Three-phase winding 8 Water injection pipe 9 Drain pipe 10 Operation panel 11 Circulation ventilation path 12 Blower fan 13 Filter 14 Rotation detection part 20 Commercial Power supply 21 Rectifier 22 Choke coil 23 Smoothing capacitor 24 Inverter circuit 24a to 24f Switching element 25 Input setting unit 26 Load drive unit 27 Water supply valve 28 Drain valve 29 Heater 30a, 30b, 30c Position detection element 31 Control unit 32 Drive circuit 33 Number of rotations Detection unit 34 Cloth amount detection unit

Claims (7)

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 unit that detects the rotation number of the motor, and a control unit that controls the rotation of the motor based on the detection output of the rotation number detection unit. First detection step of measuring the acceleration angular acceleration α1 while the rotation speed is increased from the predetermined rotation speed N1 to N2 by accelerating the rotation of the drum by generating a predetermined acceleration torque in the motor And, after the first detection step, the rotation speed of the drum is reduced by generating a predetermined deceleration torque Tc in the motor, and the rotation speed is decreased from the predetermined rotation speed N3 to N4. Measure acceleration α2. A second detecting step for measuring, and a switching step for causing the motor to generate a deceleration torque Tb in order to end the first detecting step and switch to the second detecting step, and the acceleration angular acceleration α1 Further, the washing machine detects the amount of cloth based on the angular acceleration α2 during deceleration and satisfies Tb <0 and (absolute value of Tb) <(absolute value of Tc). The washing machine according to claim 1, wherein the washing machine has a plurality of predetermined values of deceleration torque in the switching step, and the deceleration torque is changed according to an elapsed time from the start of the switching step and a rotation state of the drum. First detection of accelerating the rotation of the drum by generating at least a predetermined acceleration torque in the motor and measuring the acceleration angular acceleration α1 while the rotation speed increases from the predetermined rotation speed N1 to N2. After the step and the first detecting step, the rotation of the drum is decelerated by generating a predetermined deceleration torque Tb in the motor, and the speed is reduced while the rotation speed is decreased from a predetermined rotation speed N3 to N4. A second detection step of measuring the angular acceleration α2, and a switching step of ending the first detection step and switching to the second detection step, the acceleration angular acceleration α1 and the deceleration angular acceleration α2. In the cloth amount detection means for detecting the cloth amount, when the elapsed time from the start of the cloth amount detection is t, during the switching step, the motor is caused to generate a torque Td to increase the switching angle. Degree α3 (t) is controlled, and the angular acceleration at acceleration α1 at the end of the first detection step and the switching angular acceleration α (ts) at t = ts at the start of the switching step are substantially the same value and are switched. 3. The washing machine according to claim 2, wherein the switching angular acceleration α (te) at the time t = te at the end of the process is substantially the same value as the deceleration angular acceleration α2 at the start of the second detection process. When the elapsed time from the start of the cloth amount detection is t, the control unit starts the drum from a stationary state by generating an acceleration torque to the motor before performing the first detection step, and performs a predetermined process. The startup angular acceleration αa (t) has a startup step of increasing the rotational speed at the startup angular acceleration αa (t) to the rotational speed Na, and αa (t1)> α1 at a certain time t1 in the startup step. The washing machine according to any one of claims 1 to 3, wherein a washing machine is provided. 5. The acceleration torque and the deceleration torque of the motor are controlled by increasing or decreasing q-axis current supplied to the motor at least during the first detection step and the second detection step. The washing machine according to any one of claims. The washing machine according to any one of claims 1 to 5, wherein a d-axis current supplied to the motor is substantially zero during at least the first detection step and the second detection step. The control unit measures the maximum rotation speed and the minimum rotation speed of the drum in the predetermined rotation angle section in the first detection step, and when the difference between the maximum rotation speed and the minimum rotation speed is equal to or greater than a predetermined value, The washing machine according to any one of claims 1 to 6, wherein the rotation drive is stopped.