JP5299237B2 - 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.

  Conventionally, this type of washing machine has once started up the rotation of the motor, then stopped energizing the motor to rotate the drum inertially, and measured the change in rotational speed in a certain time interval until the drum stopped. In general, a function of detecting the amount of laundry, which is the amount of laundry, and automatically determining the washing time or the like according to the amount of fabric is added (see, for example, Patent Document 1).

  FIG. 9 is a cross-sectional view showing a schematic configuration of a drum type washing machine which is a kind of conventional washing machine, and FIG. 10 is a diagram showing a cloth amount detection method of the drum type washing machine.

  In FIG. 9, 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 projections 15 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 15 provided on the inner peripheral wall of the drum 3, and the stirring operation of dropping from the lifted appropriate height position is repeated. As a result, 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. In this rinsing process, the laundry stored in the drum 3 is rinsed by repeating a stirring operation in which the laundry is lifted by a stirring protrusion (not shown) and dropped by the rotation of the drum 3.

  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.

  Furthermore, this drum type washing machine is provided with a function of drying the 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.

  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 evenly stuck to the inner wall of the drum 3 by centrifugal force. To do. 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. 10, 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 and stops, into a partial rotation speed and outputs it.

  In FIG. 10, the horizontal axis represents time, and the vertical axis represents the rotational speed 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 Desired.

  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 Equation 2.

  Since the angular acceleration α is expressed by Equation 3 as a function of the angular velocity ω and time t, as shown in Equation 4, if the average radius r of the cloth is constant, the rotational speed, that is, the angular velocity ω, according to the weight m of the cloth. Changes.

  From 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 rotate the drum 3 by inertia and measuring the change in the rotational speed in a certain time interval until the drum 3 stops.

JP-A-5-168786

  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, due to the variation in the friction torque Tb of the drum rotation shaft, the proportional relationship between the time until the drum stops and the amount of cloth is not constant, and has different numerical values depending on each washing machine. . For this reason, there is a problem that the conventional cloth amount detection method has variations and the detection accuracy is limited.

  In addition, when the average radius r of the cloth is uniquely determined according to the weight of the cloth, the weight m of the cloth and the moment of inertia J are in a one-to-one relationship. The weight m can be detected. However, even when the weight of the cloth is constant, if cloth unevenness occurs, the cloth distribution in the drum 3 changes, and the average radius r is not determined only by the weight of the cloth. It will cause deterioration.

  In addition, although the generated torque of the motor is temperature-dependent, the above-described conventional cloth amount detection method applies a voltage with a constant pattern regardless of the temperature, so that the detection result varies depending on the temperature of the motor. there were.

  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.

  The present invention solves the above-mentioned conventional problems, and by reducing the change in the moment of inertia due to the cloth bias by stably attaching the cloth to the drum with the amount of cloth put into the drum, Stable cloth quantity detection that eliminates the influences of washing machine and clothes bias with cloth quantity detection means that can accurately detect with a simple configuration by suppressing the influence of friction torque of the drum rotating shaft and motor temperature. An object is to provide a washing machine having means.

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 and a control unit for controlling, the control unit, between the start of the operation for detecting the laundry weight of a first predetermined time ta, at startup by generating an acceleration torque Ta to the motor a starting step in the angular acceleration .alpha.a (t) increases the rotational speed of the drum, said accelerating rotation of said drum by generating the acceleration torque T1 to the motor after the activation step, the first predetermined or the rotational speed N 1 After the first detection step of measuring the acceleration angular acceleration α1 while the rotation speed is increased to the second predetermined rotation speed N2, and after the first detection step, generating the deceleration torque T2 in the motor in decelerating the rotation of the drum, and a second detection step of rotational speed from the third predetermined rotational speed N3 to fourth predetermined rotation speed N4 measures the deceleration angular acceleration α2 between the reduced And at a certain time tx during the start-up process, αa (t
x)> the angular acceleration at the time of starting that satisfies α1, and the amount of cloth is detected based on the angular acceleration at acceleration α1 and the angular acceleration at deceleration α2, and the angular acceleration at acceleration α1 When the rotational speed Na at the time is higher than the first predetermined rotational speed N1, the angular acceleration during the rotational speed increases from the rotational speed Na at the end of the starting process to the second predetermined rotational speed N2. It is characterized by doing.

  As a result, the moment of inertia is used to measure the amount of cloth using both the rising and falling speeds of the drum after the cloth is stably attached to the drum by increasing the angular acceleration in the starting process. It is possible to suppress the influence of the variation in the detection of the amount of cloth and to detect the amount of cloth accurately with a simple configuration.

  The washing machine of the present invention can accurately detect the amount of cloth with a simple configuration by stabilizing the moment of inertia and suppressing the influence of the individual device variations in the friction torque of the drum rotating shaft and the motor temperature.

Sectional drawing which shows schematic structure of the drum type washing machine which is 1 type of the 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 used for the drum type washing machine The flowchart figure which shows the cloth amount detection method used for the drum type washing machine Output torque characteristic diagram of induction motor of the drum type washing machine (A) The figure which shows the relationship between passage of time of the drum type washing machine which is a kind of washing machine in Embodiment 2 of this invention, and the rotational speed of a drum (b) The maximum of the rotational speed of the drum of the drum type washing machine Showing the relationship between the upper limit of the minimum difference and (A) The figure which shows the relationship of the passage of time of the drum type washing machine which is a kind of washing machine in Embodiment 3 of this invention, and the rotational speed of a drum (b) The passage of time of the drum type washing machine and the drum Diagram showing another relationship of rotation speed Sectional drawing which shows schematic structure of the drum-type washing machine which is a kind of conventional washing machine The figure which shows the cloth amount detection method of the drum type washing machine

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, control unit, from the start of the operation for detecting the laundry weight during the first predetermined time ta, the drum startup angular acceleration .alpha.a (t) by generating the acceleration torque Ta to the motor a startup step of increasing the rotational speed, the accelerating rotation of the drum by generating acceleration torque T1 to the motor after the activation step, the first predetermined rotational speed N 1 or et second predetermined Rotate to rotation speed N2 After the first detection step of measuring the acceleration angular acceleration α1 while the degree rises, and after the first detection step, the motor is caused to generate a deceleration torque T2 to reduce the rotation of the drum, and a second detection step of rotational speed from the third predetermined rotational speed N3 to fourth predetermined rotation speed N4 measures the deceleration angular acceleration α2 between the lowered, some time during the activation step At tx, the starting angular acceleration that satisfies αa (tx)> α1 exists, and the cloth amount is detected based on the acceleration angular acceleration α1 and the deceleration angular acceleration α2, and the acceleration angular acceleration α1 is When the rotation speed Na at the end of the activation process is higher than the first predetermined rotation speed N1, the rotation speed increases from the rotation speed Na at the end of the activation process to the second predetermined rotation speed N2. Angular acceleration between With the washing machine characterized by the above, it is possible to suppress the influence of variation in the detection of the amount of cloth by stabilizing the moment of inertia and offsetting the friction torque of the drum rotation shaft. The amount of cloth can be detected.

  In the second invention, in particular, the control unit of the first invention controls the voltage applied to the motor and the command frequency, or controls the voltage applied to the motor or the energization current, thereby starting acceleration torque Ta. By making the washing machine characterized by continuously changing (t) and controlling so that Ta = T1 at the end of the start-up process, it is not necessary to consider the effects of stepwise fluctuations in acceleration torque It becomes possible to detect the cloth amount with high accuracy.

  In the third aspect of the invention, in particular, the control unit of the first or second aspect of the invention applies a predetermined voltage to the motor and drives it at a predetermined command frequency, or controls a voltage or energization current applied to the motor. Thus, at least in the first detection step, at least in the first detection step, the washing torque is controlled so that the acceleration torque T1 changes within a predetermined range. By controlling the torque T1 so as to change within a predetermined range, it is possible to accurately detect the cloth amount without the need to consider the influence of fluctuations in the deceleration torque in a complicated manner.

  In the fourth aspect of the invention, in particular, the control unit according to any one of the first to third aspects applies at least the second detection by applying a predetermined voltage to the motor or controlling the energization current. In the process, the amount of cloth can be detected accurately without the need for complicated consideration of the effects of fluctuations in the deceleration torque by using a washing machine that is controlled so that the deceleration torque T2 changes within a predetermined range. It becomes possible to do.

  The fifth invention is characterized in that, in particular, the first detection step and the second detection step of any one of the first to fourth inventions are performed at or below a resonance frequency of a vibration system including the water tank. By using the washing machine, the cloth amount is detected without being affected by the vibration of the drum due to resonance, and the cloth amount can be detected with high accuracy.

  In a sixth aspect of the invention, in particular, in any one of the first to fifth aspects of the invention, a temperature detection unit that detects the temperature of the motor is provided, and the control unit detects the winding temperature of the motor by the temperature detection unit. By using a washing machine that corrects the detection result of the cloth amount according to the difference from the reference temperature, the cloth amount is detected in consideration of the temperature dependency of the generated torque in the motor. It becomes possible to detect the amount of cloth well.

  In a seventh aspect of the invention, in particular, in any one of the first to sixth aspects of the invention, the resistance value of the motor winding is calculated by measuring the amount of current that flows when a predetermined voltage is applied to the motor, and the resistance A winding temperature estimation unit that estimates the winding temperature from the value, and the control unit displays a detection result of the cloth amount according to a difference between the winding temperature of the motor estimated by the winding temperature estimation unit and a reference temperature. By making the washing machine to be corrected, the cloth amount is detected in consideration of the temperature dependency of the torque generated in the motor, and the cloth amount can be detected with high accuracy.

  In the eighth aspect of the invention, in particular, the controller of any one of the first to seventh aspects measures the maximum rotation speed and the minimum rotation speed of the drum in a predetermined rotation angle section in the first detection step, When the difference between the rotational speed and the minimum rotational speed is equal to or greater than a predetermined value, by making the washing machine characterized by stopping the rotational driving of the drum, the distribution of the cloth in the drum becomes uneven, Even when the vibration of the drum becomes larger than a predetermined value, the drum can be stopped safely.

  In the ninth invention, in particular, the control unit according to any one of the first to eighth inventions measures the elapsed time from the start of rotation of the drum, and the first detection is performed even if the second predetermined time tb has elapsed. When the process is not finished, the rotation time of the drum is stopped, so that the acceleration time is longer than the second predetermined time tb, such as when excessive clothing is thrown in, etc. In such a case, it is possible to stop the rotational driving of the drum and move to the next step.

  In the tenth aspect of the invention, in particular, the control unit of any one of the first to ninth aspects of the invention measures the elapsed time from the start of rotation of the drum, and the second detection is performed even if the third predetermined time tc has elapsed. When the process is not finished, the rotation driving of the drum is stopped, and the washing machine is characterized in that the acceleration time and the deceleration time are the second predetermined time tc when excessive clothing is put in. In the case where it becomes longer than this, the rotational drive of the drum can be stopped and the next process can be started.

  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 configuration of a drum type washing machine which is a kind of washing machine according to the first embodiment of the present invention. FIG. 2 is a circuit diagram showing a control device of the drum type washing machine. 3 is a diagram showing an operation for detecting the amount of cloth used in the drum type washing machine, FIG. 4 is a diagram showing a cloth amount for detecting the amount of cloth used in the drum type washing machine, and an acceleration difference, and FIG. FIG. 6 is a flowchart showing a cloth amount detection method used in the drum type washing machine, and FIG. 6 shows an output torque characteristic diagram of the induction motor 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 operation instruction input from the input setting unit 25 and the monitoring information of the operation state detected by each detection means (not shown), and the water supply valve 27 is controlled by the load drive 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. A speed signal detected by the motor rotation speed detection means 30 is input to a 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, thereby rotating the rotor to the required rotational speed. Rotate with

  The control unit 31 includes a drum speed detection unit 33 to which the detection output of the motor rotation speed 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 rotation speed.

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

  FIG. 3 shows the relationship between the time required to increase the rotation speed of the drum 3 and the time required to decrease the rotation 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, the acceleration torque Ta is generated by the motor 7 during the elapsed time t to start the drum 3 from a stationary state, and the angular acceleration αa (t at startup for a first predetermined time ta. ) To start up the rotation speed. Next, following the start-up step, a first detection step is performed in which the acceleration torque T1 is generated by the motor 7, the rotational speed is increased by ΔN1 from the rotational speed N1, and the time t1 to reach N2 is measured. After this 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 the rotation speed is decreased by ΔN2 from the rotation speed N3. And a second detection step of measuring a time t2 to reach a predetermined rotational speed N4 is performed.

  In the startup process, the angular acceleration may change depending on the elapsed time in order to start the drum 3 from a stationary state. At least at a certain time tx in the startup process, the angular acceleration αa ( tx) is such that αa (tx)> α1 with respect to the angular acceleration α1 in the first detection step, that is, by having a larger angular acceleration than in the first detection step, the acceleration of the drum 3 is accelerated. Control to be.

  In particular, at the time of start-up, if the angular acceleration is low, the cloth does not stick to the drum 3 due to rotation near the bottom of the drum 3, or if the rotational speed is increased in such a state, the cloth is biased. As a result, the first detection process is performed, and the accuracy of the cloth amount detection is deteriorated. In order to prevent the cloth from becoming unstable in this way, the angular acceleration αa (tx) at the start time at a certain time tx is made larger than the angular acceleration α1 in the first detection step, and the weight of the cloth Stabilizes the relationship with the moment of inertia.

  Further, regarding the rotational speed N1 in the first detection step and the rotational speed N4 in the second detection step, it is an essential condition that the cloth sticks to the drum 3 at each rotational speed. That is, it is necessary to set the rotation speed higher than the rotation speed at which gravity is equal to the vertical upward component of the centrifugal force generated by the rotation of the drum 3. This is the operation indicated by the solid line in FIG.

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

  From Equation 3 shown in the background art, the angular acceleration α1 in the first detection step is expressed by Equation 5.

  Further, Expression 6 is established from Expression 1 and Expression 2 of the background art.

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

  When the component of the friction torque Tb is eliminated from Equation 6 and Equation 8, Equation 9 is obtained.

  FIG. 4 is a diagram in which the horizontal axis represents the amount of cloth and the vertical axis represents the acceleration difference, and shows the above formula 9 in an easily understandable manner.

  When the average radius r, acceleration torque T1, and deceleration torque T2 in the drum inner periphery of the cloth are constant values, Equation 9 corresponds to the weight m of the cloth (α1-α2) as shown in FIG. Indicates a change.

  Here, α1 and α2 can be easily obtained by measuring the relationship between the rotational speed of the drum 3 and time, as shown in 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.

  When the starting process end rotation speed Na is smaller than the first detection process start rotation speed N1, the operation described above is performed.

  Next, the operation indicated by the alternate long and short dash line in FIG. 3 will be described. This is a case where the friction torque of the drum rotation shaft is small and the drum rotation speed exceeds N1 during the starting process.

  Since the angular acceleration of the drum 3 during the starting process changes with time, even if the time for reaching the rotational speed N1 to N2 is measured, the angular acceleration during that time cannot be obtained.

In this case, the drum rotational speed Na ′ at the end of the acceleration torque starting process in the starting process is set as the starting rotational speed of the first detection process, and the time t1 ′ from the rotational speed Na ′ to the rotational speed N2 is measured and measured. After completion, ΔN1 = N2−Na ′ and t1 = t1 ′, and the above-described calculation of the cloth amount may be performed.

  The cloth amount detection method will be described with reference to FIG.

  In FIG. 5, when the cloth amount detection starts (step S1), the control unit 31 drives the motor 7 with the acceleration torque Ta (t) (step S2) to increase the rotation speed of the drum 3 (step S3). ). When the first predetermined time ta elapses from the start of the cloth amount detection, the starting process is terminated (step S4). At this time, the acceleration torque is controlled to be the acceleration torque T1 in the first detection step (step S5).

  Here, the rotation speed Na at the end of the starting process is compared with a predetermined rotation speed N1 (step S6), and if Na <N1, the acceleration is continued until the predetermined rotation speed N1 is reached (step S7). When the rotation speed reaches N1, measurement of time t1 is started (step S8). Thereafter, acceleration is continued, and when the drum 3 reaches the rotational speed N2 (step S9), a time t1 required for the rotational speed to increase by ΔN1 is calculated (step S10).

  If Na> N1 in step S6, the starting process end rotational speed Na ′ is stored (step 11), ΔN1 = N2−Na ′ is set based on this (step S12), and measurement of time t1 ′ is started. (Step S8 '). After that, when acceleration continues and the drum 3 reaches the rotational speed N2 (step S9 ′), a time t1 ′ required for the rotational speed to increase by ΔN1 is calculated, and t1 = t1 ′ is set (step S10 ′). ).

  Next, the motor 7 is driven with the deceleration torque T2 to start a decrease in the rotational speed (step S13). When the drum 3 reaches the predetermined rotational speed N3 (step S14), the measurement of the time t2 is started (step S15), and when the rotational speed reaches the predetermined rotational speed N4 decreased by ΔN2 (step S16). The time t2 required for the rotational speed to drop by ΔN2 is calculated (step S17).

  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 Equations 5 and 7, and the difference α1-α2 between the two angular accelerations is calculated. Obtaining (step S18), from the relationship between the determination value S and the cloth amount measured in advance, the cloth amount is obtained based on Equation 9 (step S19), and the cloth amount detection is terminated (step S20).

  In order to accurately detect the amount of cloth using Equation 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. 6, and the acceleration torque T1 changes according to the difference (slip) between the command frequency and the actual rotational speed. In this case, by appropriately setting N1 and N2, the torque fluctuation in the detection process can be suppressed to a narrow range of 5 to 10%. High detection results can be obtained. The same applies to the deceleration torque T2.

  Note that the output torque of the motor 7 has a characteristic that changes depending on the temperature of the windings constituting the motor 7. Specifically, the output torque changes in proportion to the current flowing through the winding of the motor 7, but the resistance value of the winding changes with temperature as shown in Equation 10 below, so when the same voltage is applied As the value of the flowing current changes, the output torque also changes.

  Note that Rt is a resistance value at a temperature t ° C., R 0 is a resistance value at 0 ° C., and α is a temperature coefficient that varies depending on the substance. In the case of copper, it is about 0.0004.

  Here, the current It at the temperature t ° C. is expressed by Equation 11 according to Ohm's law when the current E when the voltage E is applied at the temperature 0 ° C. is multiplied by the correction coefficient “1 + αt” to the detection result. Thus, it is possible to correct the influence of the change in the output torque of the motor 7 due to the temperature.

  Measuring the temperature of the winding can be realized by winding a temperature detecting means 35 constituted by a thermistor or the like into the winding and processing the detected temperature information by the control unit 31. Further, it is also possible to calculate the resistance value of the winding by measuring the amount of current flowing when a predetermined voltage is applied to the motor 7 and estimate the winding temperature from this resistance value.

  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. Further, since the determination value is corrected in consideration of the change in the output torque due to the change in the winding temperature of the motor, the influence of the temperature is suppressed, so that highly accurate detection is possible.

  In the present embodiment, the rotation of the motor 7 is transmitted to the pulley 16 fixed to the rotating shaft of the drum 3 via the belt 15, but the motor 7 is directly connected to the rotating shaft of the drum 3. Thus, the same effect can be obtained with the driving configuration.

Further, the rotational speed of the motor 7 is detected, and the rotational speed of the drum 3 is calculated based on the detected rotational speed. However, the same effect can be obtained when the rotational speed of the drum 3 is directly detected.
In addition, although an induction motor is used as the motor 7, the same effect can be obtained by using another motor such as a permanent magnet motor. In that case, as a control method for reducing the variation in torque, a method for controlling the motor applied voltage and the energized current can be cited.

(Embodiment 2)
FIG. 7A is a diagram showing the relationship between the passage of time of a drum type washing machine which is a type of washing machine according to Embodiment 2 of the present invention and the rotational speed of the drum, and FIG. The figure which shows the relationship of the upper limit of the difference of the maximum and minimum of the rotational speed of the drum of a washing machine is shown.

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 between the second embodiment and the first embodiment is that when the rotational speed of the drum 3 is increased in order to detect the amount of cloth, the drum 3 is changed according to the change in the rotational speed accompanying the increase in the rotational speed. It is the point which provided the control which stops the rotational drive of.

  FIG. 7A 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 applied, and the rotational speed of the drum 3 is increased, and the vertical axis is the rotational speed of the drum 3. . As illustrated, 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 second 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 the predetermined rotation angle section during the acceleration of the rotation of the drum 3. 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.

  As shown in FIG. 7B, 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. 7B may be set based on the allowable range of vibration obtained experimentally at each rotation speed of the drum 3.

  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 known 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.

  As described above, in the second embodiment, the balance of the laundry is poor 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. As a result, the situation where the washing tub vibrates greatly and collides with the main body of the washing machine is avoided, and after stopping, it is started again and detected, or it is determined as a predetermined amount of cloth and proceeds to the next process. It becomes possible.

(Embodiment 3)
FIG. 8A is a diagram showing the relationship between the passage of time of a drum type washing machine which is a type of washing machine according to Embodiment 3 of the present invention and the rotational speed of the drum, and FIG. The figure which shows another relationship between progress of the time of a washing machine and the rotational speed of a drum is shown.

  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 difference between the third embodiment and the first embodiment is that when the rotational speed of the drum 3 is increased / decreased in order to detect the amount of cloth, there is a time limit, and when a predetermined time has elapsed, the drum 3 is provided with control for stopping the rotational drive.

FIG. 8A 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 applied, 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 a heavy load is applied to the drum 3 such as clothes wet in water, the output torque of the motor 7 may be insufficient, and the rotation speed may not be increased to the end rotation speed N2 of the first detection step. . In this case, when a predetermined first predetermined time Tend1 elapses from the start of the rotation of the drum 3, the rotation driving of the drum 3 is stopped and the process proceeds to the next step.

  In addition, even when a heavy load is applied and the rotational speed is increased to the rotational speed N2, as shown in FIG. 8B, if the sum of the friction torque Tb and the deceleration torque is small, the second detection process ends. The time to reach the rotational speed N4 may become longer. In this case, when a predetermined second predetermined time Tend2 has elapsed from the start of the rotation of the drum 3, the rotation driving of the drum 3 is stopped and the process proceeds to the next step.

  As described above, in the third embodiment, even when the first predetermined time or the second predetermined time has elapsed since the start of drum rotation, the first detection process or the second detection process is completed. By controlling to stop the rotation of the drum when there is not, it is possible to proceed to the next process without taking more time than necessary for the cloth amount detection process.

  According to the present invention, it is possible to accurately detect the amount of cloth put on the drum with a simple configuration, and to perform an appropriate washing time setting, detergent amount display, and an 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 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 35 Temperature detection part 36 Winding temperature estimation part

Claims (10)

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 speed detection device that detects the rotation speed of the motor, and a control unit that controls the rotation of the motor based on the detection output of the rotation speed detection device,
The controller is
Between the start of the operation for detecting the laundry weight of a first predetermined time ta, increasing the rotational speed of the drum at startup angular acceleration .alpha.a (t) by generating the acceleration torque Ta to the motor A starting process to
The activation the accelerating rotation of the drum in the acceleration torque T1 to be generated in the motor after the step, the rotational speed is increased to a first predetermined rotational speed N 1 or et second predetermined rotational speed N2 A first detection step of measuring an acceleration angular acceleration α1 during acceleration;
After the first detection step, the rotation of the drum is decelerated by causing the motor to generate a deceleration torque T2, and the rotation speed is increased from a third predetermined rotation speed N3 to a fourth predetermined rotation speed N4. and a second detection step of measuring the deceleration angular acceleration α2 between the lowered,
At a certain time tx in the starting process, the starting angular acceleration satisfying αa (tx)> α1 exists, and the cloth amount is detected based on the acceleration angular acceleration α1 and the deceleration angular acceleration α2 .
When the rotation speed Na at the end of the starting process is higher than the first predetermined rotation speed N1, the angular acceleration at acceleration α1 is set to the second predetermined rotation speed from the rotation speed Na at the end of the starting process. A washing machine, characterized in that the angular acceleration is increased while the rotational speed is increased to N2 . The control unit continuously changes the starting acceleration torque Ta (t) by controlling the voltage applied to the motor and the command frequency, or by controlling the voltage applied to the motor or the energization current. 2. The washing machine according to claim 1, wherein the washing machine is controlled so that Ta = T1 at the end. The control unit applies a predetermined voltage to the motor and drives the motor at a predetermined command frequency, or controls the voltage or energization current applied to the motor, so that at least in the first detection step, the acceleration torque T1 The washing machine according to claim 1, wherein the washing machine is controlled to change within a predetermined range. The control unit controls the deceleration torque T2 to change within a predetermined range at least in the second detection step by applying a predetermined voltage to the motor or controlling an energization current. The washing machine according to any one of claims 1 to 3, wherein: 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 less of a vibration system including the water tank. A temperature detection unit that detects the temperature of the motor is provided, and the control unit detects the winding temperature of the motor by the temperature detection unit, and corrects the detection result of the cloth amount according to a difference from a reference temperature. The washing machine according to any one of claims 1 to 5. A resistance value of the motor winding is calculated by measuring the amount of current that flows when a predetermined voltage is applied to the motor, and includes a winding temperature estimation unit that estimates the winding temperature from the resistance value. The cloth amount detection result is corrected according to a difference between the winding temperature of the motor estimated by the winding temperature estimation unit and a reference temperature, according to any one of claims 1 to 6. Washing machine. In the first detection step, the control unit measures the maximum rotation speed and the minimum rotation speed of the drum in a predetermined rotation angle section, and if the difference between the maximum rotation speed and the minimum rotation speed is equal to or greater than a predetermined value, the drum The washing machine according to any one of claims 1 to 7, wherein the rotation driving of the washing machine is stopped. The control unit measures the elapsed time from the start of rotation of the drum, and stops the rotation drive of the drum when the first detection step is not finished even after the second predetermined time tb has elapsed. The washing machine according to any one of claims 1 to 8. The control unit measures the elapsed time from the start of rotation of the drum, and stops the rotation of the drum when the second detection step is not finished even after the third predetermined time tc has elapsed. The washing machine according to any one of claims 1 to 9.

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