JP4656660B2 - 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 an amount of laundry put in a rotating 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 rotating 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 rotary 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 that it can be opened and closed. The laundry can be taken in and out of the rotary drum 3 through the clothing entrance 4.

  The rotating drum 3 is formed with a large number of through holes 6 communicating with the inside of the water tank 2 on its peripheral surface, and provided with stirring protrusions (not shown) at a plurality of positions on the inner peripheral surface. The rotary drum 3 is rotationally driven in the forward and reverse directions by a drum drive 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 rotating 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 pipe is placed in the water tank 2. A predetermined amount of water is injected from the passage 8 and the drum 3 is rotated by the drum drive motor 7 to start the washing process. By the rotation of the rotating drum 3, the laundry accommodated in the rotating drum 3 is lifted in the rotating direction by the stirring protrusion provided on the inner peripheral wall of the rotating drum 3, and the stirring operation of dropping from the lifted appropriate height position Is repeated, so that 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 rotary drum 3 at a high speed. Rinsing is performed by pouring water from the path 8. Also in this rinsing step, the laundry stored in the rotating drum 3 is rinsed by repeating the stirring operation in which the laundry is lifted and dropped by the stirring protrusion by the rotation of the rotating drum 3.

  This drum type washing machine is provided with a function of drying laundry stored in the rotary drum 3, and the air in the water tank 2 is exhausted and dehumidified by the circulation air passage 11 to be heated and dried. Is again blown into the water tank 2. 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. Further, a rotation detection unit 14 for detecting the rotation of the drum drive motor 7 is provided.

  In the drum type washing machine having the above-described configuration, the amount of laundry such as clothes put into the rotary drum 3 is detected, and the washing time and the like are determined according to the amount of laundry. 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 a drum drive motor 7 for driving the rotary drum 3 to rotate.

  When washing is started, first, the control circuit starts the drum drive motor 7, and a detection output is input from the rotation detection unit 14. The detection frequency of the rotation detector 14 changes linearly with the rotation of the drum drive motor 7. The control circuit increases the average voltage of the power supply voltage of the drum drive 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 drum drive motor 7 is gradually increased inside the control circuit to shift to high speed rotation, and the clothing is uniformly applied to the inner wall of the rotary drum 3 by centrifugal force. Make it stick. In this state, the rotation of the drum drive motor 7 is stopped after continuing the rotation for a predetermined time. Thereby, the inertial rotation of the rotary drum 3 is in a state of rotating the drum drive motor 7 in reverse.

  At this time, as shown in FIG. 6, the rotation detection unit 14 converts the inertial rotational force of the rotary drum 3 to gradually decrease due to a mechanical loss and stops and converts it into a minute rotational speed and outputs it. In FIG. 6, the horizontal axis represents time, and the vertical axis represents the number of rotations of the drive motor (drum drive motor). The time from the stop of energization to the stop of the rotary 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.

  That is, the centrifugal force F applied to the cloth can be obtained by the following equation, where m is the weight of the cloth per unit volume, r is the radius of the rotating drum 3, and ω is the rotational angular velocity.

F = mrω ²
If the number of revolutions per minute is constant, the rotational angular velocity ω and the radius r of the rotating drum are constant, so that the cloth centrifugal force F is proportional to the weight m.

When the energization of the drum drive motor 7 is stopped, the centrifugal force F becomes the initial inertial rotational force of the rotating drum 3. Accordingly, the time until the rotating drum 3 stops is proportional to the centrifugal force F, that is, the cloth amount.
JP-A-5-168786

  When the conventional cloth amount detection method is used, a proportional relationship between the amount of time until the rotary drum stops and the inertial rotational force of the rotating drum gradually decreases due to mechanical loss and the amount of cloth is experimentally determined. I will leave. The obtained measurement value is applied to all washing machines of the same model. However, due to the effect of variations in the frictional resistance of the drum rotating shaft, the proportional relationship between the time until the rotating drum stops and the amount of cloth is not constant and varies depending on the washing machine. Therefore, the detection accuracy of the conventional cloth amount detection method has a limit.

  Therefore, the present invention provides a washing machine having a cloth amount detecting means capable of accurately detecting a cloth amount put into a rotary drum with a simple configuration while suppressing the influence of variation in frictional resistance of the drum rotation shaft. For the purpose.

In order to solve the above-described problems, a washing machine of the present invention has a rotation center shaft in a horizontal direction or an inclination direction, and includes a rotation drum that accommodates laundry, and the rotation drum that rotatably includes the rotation drum. A drum that is elastically supported on the drum, a drum drive motor that rotationally drives the drum, a rotational speed detector that detects the rotational speed of the drum drive motor, and the drum drive based on the detection output of the rotational speed detector A control unit that controls the rotation of the motor, and the control unit accelerates the rotation of the rotating drum with a predetermined torque by the drum drive motor to detect the cloth amount, and rotates from the rotation speed A. When the rising time T until reaching the speed B is measured, and the driving by the drum drive motor is stopped and the rotary drum is rotated by inertia, the rotation speed C reaches the rotation speed D. Measuring the fall time t until the, makes a comparison between the sum and the preset determination value by calculating the sum of the rising time T the fall time t, it is larger laundry amount as the sum is greater It is determined .

  According to the washing machine having the above-described configuration, the cloth amount is measured using both the rotation speed of the rotating drum and the speed of lowering, so that the variation in the frictional resistance of the drum rotation shaft is offset and the influence of the variation is suppressed. It is possible to accurately detect the amount of cloth with a simple configuration.

  In the washing machine of the present invention configured as described above, the rotation control unit is configured to detect a maximum rotation speed of the rotating drum in a predetermined rotation angle section during acceleration of rotation of the rotating drum in the step of detecting the cloth amount. It is preferable that the minimum rotational speed is measured, and the rotational driving of the rotary drum is stopped when the difference between the maximum rotational speed and the minimum rotational speed is a predetermined value or more.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(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, the AC power of the commercial power supply 20 is rectified by a rectifier 21, and the DC power smoothed by a smoothing circuit including a choke coil 22 and a smoothing capacitor 23 is used as driving power, and a drum is driven by an inverter circuit 24. The drive motor 7 is rotationally driven. Further, the rotation of the drum drive 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 load drive unit 26 supplies water. The operation of the valve 27, the drain valve 28, the blower fan 12, and the heater 29 is controlled.

  The drum drive 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. Then, the rotation is controlled by the PWM control inverter circuit 24 constituted 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 period 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 period. The detection output of the rotation speed detection unit 33 is supplied to the cloth amount detection unit 34, and the cloth amount is detected based on the detected rotation speed as described below. Since the detection output of the rotation speed detection unit 33 corresponds to the rotation speed of the rotation drum 3, the rotation speed of the rotation drum 3 is obtained from the detection output of the rotation speed detection unit 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. 2A shows the relationship between the frictional resistance of the drum rotating shaft, the time required for increasing the rotational speed of the rotating drum 3, and the time required for decreasing the rotational speed due to inertial rotation. The horizontal axis is the frictional resistance of the drum rotation axis, and the vertical axis is the time. The rising times T1 and T2 indicate the time required for raising the rotary drum 3 from the predetermined rotational speed A to the predetermined rotational speed B. The descent times t1 and t2 indicate the time required for the descent from the predetermined rotation speed C to the predetermined rotation speed D when driving of the rotary drum 3 is stopped and inertial rotation is performed. The rise time T1 and the fall time t1 indicate a case where measurement is performed with the same cloth amount, and the rise time T2 and the drop time t2 indicate a case where measurement is performed with a larger same cloth amount. The total time (T1 + t1) and the total time (T2 + t2) indicate the total time of the rise time and the fall time.

  As shown in FIG. 2A, when the rotational speed of the rotary drum 3 is increased, the required times T1 and T2 become longer as the frictional resistance increases. When the rotational speed of the rotating drum 3 decreases due to inertial rotation, the required times t1 and t2 become shorter as the frictional resistance increases. The total time (T1 + t1) and the total time (T2 + t2) are constant regardless of the frictional resistance because the influence of the frictional resistance is offset. The difference between the total time (T1 + t1) and the total time (T2 + t2) corresponds to the difference in the amount of cloth. Accordingly, if the relationship between the total time (T + t) and the cloth amount as shown in FIG. 2B is measured with the judgment value S, the judgment value S is obtained by rotating the rotary drum 3 and FIG. Based on the relationship b), it is possible to accurately detect the amount of cloth while avoiding the influence of variations in the frictional resistance of the drum rotation shaft.

  FIG. 3 is a flowchart showing the cloth amount detection method according to the present embodiment. When the cloth amount detection starts (step S1), the control unit 31 drives the drum drive motor 7 to increase the rotation speed of the rotary drum 3 from the predetermined rotation speed A with a predetermined torque, and to perform a predetermined rotation. Control is performed to reach speed B (step S2). When the rotary drum 3 reaches the rotational speed B (step S3), a time T required to reach the rotational speed B from the rotational speed A is calculated (step S4).

  Next, the drum drive motor 7 is stopped and the inertial rotation of the rotary drum 3 is started (step S5). When the rotary drum 3 reaches the predetermined rotational speed D from the predetermined rotational speed C (step S6), a required time t required to reach the rotational speed D from the rotational speed C is calculated (step S7). Next, the total time (T + t) = determination value S is obtained (step S8), and the cloth amount is obtained from the relationship between the previously determined determination value S and the cloth amount (step S9).

(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 in the first embodiment.
It is the same as that of description. The difference in the present embodiment is that when the rotational speed of the rotary drum 3 is increased in order to detect the amount of cloth, the rotation of the rotary drum 3 is driven according to the change in the rotational speed accompanying the increase in the rotational speed. This is the point of providing control for stopping.

  FIG. 4A shows how the rotational speed of the rotating drum 3 increases with time. The horizontal axis represents the elapsed time when the drum drive motor 7 is driven and the rotational speed of the rotary drum 3 is increased by a predetermined torque, and the vertical axis is the rotational speed of the rotary drum 3. As shown in the figure, the rotational speed of the rotating drum 3 does not increase uniformly, but increases while repeating vertical movement. This is because the washing tub vibrates due to the balance of the laundry accommodated in the rotary 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 rotation drum 3 in a predetermined rotation angle section during the acceleration of the rotation of the rotation drum 3. If the difference is greater than or equal to a predetermined value, control is performed to stop the rotation of the rotary drum 3. As the maximum rotation speed and the minimum rotation speed of the rotary 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. 4B, an 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 rotary drum 3, and is provided as a table in the control unit 31. deep. The upper limit value of the difference between the maximum rotation speed and the minimum rotation speed as shown in FIG. 4B may be set based on an experimentally determined allowable vibration range at each rotation speed of the rotary 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 rotating drum 3 does not exceed the upper limit value, the laundry tub is It is possible to avoid such a situation that it vibrates greatly and collides with the washing machine body.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to detect the quantity of cloth thrown into the rotating drum with a simple configuration with high accuracy, and to perform a good dehydration process, which is useful for household and commercial washing machines. .

The circuit diagram which shows the control apparatus of the drum type washing machine in Embodiment 1 of this invention The figure which shows the principle of the cloth amount detection method used for the drum type washing machine Flow chart showing the cloth amount detection method 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 a drum type washing machine The figure which shows the cloth amount detection method of the drum type washing machine of a prior art example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Washing machine main body 2 Water tank 3 Rotating drum 4 Clothes entrance / exit 5 Door 6 Through-hole 7 Drum drive motor 7a, 7b, 7c Three-phase winding 8 Water injection line 9 Drain line 10 Operation panel 11 Circulation ventilation path 12 Blower fan 13 Filter DESCRIPTION OF SYMBOLS 14 Rotation detection part 20 Commercial power supply 21 Rectifier 22 Choke coil 23 Smoothing capacitor 24 Inverter circuit 24a-24f Switching element 25 Input setting part 26 Load drive part 27 Water supply valve 28 Drain valve 29 Heater 30a, 30b, 30c Position detection element 31 Control part 32 Drive circuit 33 Rotation speed detection unit 34 Cloth amount detection unit

Claims (2)

A rotating drum having a central axis of rotation in a horizontal direction or an inclined direction and accommodating laundry;
A water tub enclosing the rotating drum rotatably and elastically supported in the washing machine body;
A drum drive motor for rotating the drum;
A rotational speed detection device for detecting the rotational speed of the drum drive motor;
In the washing machine provided with a control unit that controls the rotation of the drum drive motor based on the detection output of the rotation speed detection device,
The control unit accelerates the rotation of the rotating drum with a predetermined torque by the drum drive motor to detect the amount of cloth, which is the amount of the laundry, until the rotation speed A reaches the rotation speed B. And the descent time t from the rotational speed C to the rotational speed D when the rotary drum is inertially rotated after stopping the driving by the drum drive motor is measured, A washing machine characterized in that the sum of the rising time T and the falling time t is calculated and compared with a predetermined determination value and the sum, and it is determined that the amount of cloth increases as the sum increases .   The rotation control unit measures the maximum rotation speed and the minimum rotation speed of the rotating drum in a predetermined rotation angle section in the middle of accelerating the rotation of the rotating drum in the step of detecting the cloth amount, and the maximum rotation speed The washing machine according to claim 1, wherein when the difference between the rotation speed and the minimum rotation speed is equal to or greater than a predetermined value, the rotation driving of the rotating drum is stopped.

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