JPH11216296A - Drum type centrifugal dehydration device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust the balance of a drum in a short time. SOLUTION: The drum 5 is rotated at a rotation speed for sticking a part of laundry to a peripheral wall surface inside the drum 5 by centrifugal force, rotating it and turning the other laundry to a tumbling state on the inner peripheral side. Then, when an eccentric load A by unevenly distributed laundry reaches the upper part of the drum 5, the rotation speed of the drum 5 is quickly raised. Then, the laundry in the tumbling state is stuck near a position facing the previous eccentric load A and generates the eccentric load B and the eccentric amount of the entire drum 5 is reduced by the balance of the eccentric loads A and B. Then, when the eccentric amount is equal to or less than a stipulated value, high-speed dehydration rotation is started.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a drum type centrifugal dehydrator.

[0002]

2. Description of the Related Art A drum type washing machine has a structure in which laundry is accommodated in a basket-shaped drum and the drum is rotated about a horizontal axis. During centrifugal dehydration with this type of washing machine, if the drum is rotated at high speed with the laundry not being evenly distributed on the inner peripheral wall of the drum, abnormal vibration and abnormalities may occur due to imbalance in the mass distribution around the rotation axis. Noise is generated. On the other hand, in a commercially available drum-type washing machine, a weight is attached around an outer tub in which a drum is installed in order to suppress the abnormal vibration. For this reason, this type of conventional washer-dryer was very heavy, and the installation place was limited, and it was difficult to move and transport.

Several centrifugal dehydrators for solving the above-mentioned problem of abnormal vibration have been proposed. For example, in a centrifugal dehydrator described in Japanese Patent Application Laid-Open No. 6-254294, a method is disclosed in which balance is adjusted by low-speed rotation of a drum before performing dehydration operation by high-speed rotation of a drum. More specifically, a two-stage rotation control in which the drum is rotated at a low speed for a very short time, and then the drum is rotated at a rotation speed slightly higher than the rotation speed but sufficiently lower than the rotation speed during the spin-drying operation. The combination allows the laundry to be distributed substantially evenly on the inner periphery of the drum.

In the above-mentioned prior art, a vibration monitoring sensor is installed on a pedestal portion of the apparatus as means for detecting uneven distribution of the laundry inside the drum, and the rotational speed of the drum is increased to a high rotational speed for performing a dehydrating operation. When the vibration monitoring sensor detects abnormal vibration, the rotation speed is reduced.

[0005]

However, in the drum rotation control method according to the prior art, since the probability that the laundry is uniformly distributed is not high, the balance adjustment by low-speed rotation of the drum and the eccentricity by high-speed rotation of the drum are not necessarily performed. There is a high possibility that load detection is repeated many times. As a result, the time required for dehydration may be prolonged, and in the worst case, the dehydration may not be completed forever.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a drum-type centrifugal dewatering apparatus capable of quickly completing the balance adjustment of laundry at the start of dewatering. To provide.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a washing machine accommodated in a drum by rotating the drum at a high speed about a horizontal axis. In a drum type centrifugal dewatering device for dewatering articles, a) a motor for rotating and driving the drum, b) an eccentric load detecting means for detecting an eccentric load of the drum, and The first speed is slightly higher than the rotation speed at which the acting centrifugal force and gravity are substantially balanced.
When the eccentric load detected by the eccentric load detecting means reaches the upper part of the drum, the centrifugal force acting on all the laundry in the drum becomes larger than gravity when the drum is rotated at the rotation speed of Rotation control means for controlling the motor so as to rapidly increase the rotation speed of the drum to the rotation speed of 2.

The centrifugal force acting on each piece of laundry stored in the drum depends on the distance from the drum rotation axis to the laundry, and is closer to the drum rotation axis than to the laundry that is in close contact with the inner peripheral wall of the drum. The centrifugal force acting on the laundry located in is small. Therefore, when the drum is rotated at the first rotation speed by the rotation control means, a portion of the laundry adheres to the inner peripheral wall surface of the drum due to centrifugal force and rotates together with the drum, and the other laundry rotates with the drum. It is in a so-called tumbling state, in which a sufficient centrifugal force cannot be obtained on the inner peripheral side of the object, and it is lifted with the rotation of the drum and falls downward due to gravity on the way.

In such a state, the eccentric load detecting means detects the position of the eccentric load caused by the laundry rotating on the inner peripheral wall of the drum. The rotation control means includes:
As soon as the eccentric load reaches the top of the drum, the rotation speed of the drum is rapidly increased to a second rotation speed. Then
The laundry in the tumbling state immediately before that is stuck near the position facing the eccentric load on the inner circumference of the drum due to centrifugal force, and rotates with the drum. As a result, the eccentric load of the entire drum becomes small due to the balance between the eccentric load generated initially and the uneven distribution of the laundry generated at the time of rapid acceleration.

The timing at which the drum is raised from the first rotation speed to the second rotation speed is basically when the eccentric load reaches the upper portion of the drum, but the eccentric load depends on factors such as the degree of acceleration. The load may be set at an appropriate position before the load reaches the drum maximum position or after the load passes the drum maximum position.

Incidentally, the drum has a specific resonance frequency corresponding to the diameter and weight of the drum, and the resonance frequency of a generally used drum is such that the centrifugal force acting on the laundry and the gravity balance the gravity. Higher than the speed, but lower than the rotation speed at which sufficient dehydration can be performed. When the rotation speed reaches the resonance frequency in a state where the drum is not balanced, large vibration is generated. Therefore, in the centrifugal dehydrator according to the present invention, the second rotation speed is set to a rotation speed lower than the resonance frequency. Is preferred.

Further, the centrifugal dewatering apparatus according to the present invention further comprises a determining means for determining the magnitude of the eccentric load,
The rotation control means, when the determination means determines that the eccentric load is equal to or less than a predetermined value while the drum is rotating at the second rotation speed, reduces the rotation speed of the drum to a high dehydration rotation speed. It is possible to adopt a configuration in which the motor is controlled to be raised.

According to this configuration, it is confirmed that the eccentric load is reduced by the above-described rotation control of the drum, and when it is determined that the vibration is small even if the drum is rotated at a high dehydration rotation speed. Only at this time, the drum passes through a rotation speed corresponding to the resonance frequency and is further raised to the spin-drying rotation speed. Therefore, vibration and noise are reliably avoided.

Further, in the centrifugal dehydrator according to the present invention, the eccentric load detecting means may be configured to detect an eccentric load based on a change in a driving current of a motor.

That is, when the motor is controlled so as to keep the rotation speed substantially constant, the drive current of the motor fluctuates under the influence of load torque fluctuation. If an eccentric load is present on the drum, the eccentric load causes the largest load torque fluctuation. Therefore, the drive current of the motor fluctuates according to the position of the eccentric load on the inner circumference of the drum (that is, during one rotation of the drum). Therefore, the position of the eccentric load can be relatively easily detected by monitoring the drive current of the motor.

In the above-mentioned centrifugal dewatering apparatus according to the present invention, the rotation control means may control the centrifugal force acting on all the laundry to be smaller than gravity before rotating the drum at the first rotation speed. It is preferable that the motor be controlled so that the left and right reversing operation is performed at the rotation speed.

When such a left-right reversal rotation operation is performed, the loosening of the laundry entangled with each other in the drum proceeds, and each laundry easily moves individually. Therefore, when the drum is rotated next at the first rotation speed, the laundry is likely to be appropriately dispersed.

[0018]

According to the drum type centrifugal dewatering apparatus of the present invention, the balance of the drum can be quickly adjusted, so that the time required for dewatering and hence the time required for washing can be prevented from being prolonged. Further, generation of large vibration and noise during the high-speed dehydrating operation can be reliably prevented.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a washing machine provided with a drum type centrifugal dehydrator according to the present invention will be described below with reference to the drawings. First, the configuration of the washing machine according to the present embodiment will be described with reference to FIGS. FIG. 1 is a side sectional view of the washing machine, and FIG. 2 is a sectional view taken along line aa of FIG.

An outer tub 2 is suspended by a spring 3 and a damper 4 inside the outer box 1, and a drum 5 for containing laundry is supported by a main shaft 8 inside the outer tub 2. A door 7 for opening and closing the front opening of the outer tub 2 is provided on the front surface of the outer box 1, and laundry is stored inside the drum 5 by opening the door 7. A large number of water holes 6 are provided in the peripheral wall of the drum 5, and water supplied to the outer tub 2 flows into the drum 5 through the water holes 6, and conversely, from the laundry in the drum 5. The dehydrated water is scattered to the outer tub 2 through the water holes 6. On the inner periphery of the drum 5, baffles 9 for scraping up the laundry with the rotation are arranged at a rotation angle of 120 ° from each other.

The main shaft 8 is held by a bearing 10 mounted on the outer tub 2, and a main pulley 11 is attached to a tip of the main shaft 8. A motor 12 is arranged on the lower surface of the outer tub 2, and the rotational driving force of the motor 12 is transmitted to the main pulley 11 via a motor pulley 13 and a V-belt 14. An opening is provided on the ring of the main pulley 11 at one place on the circumference, and a rotation sensor 19 including a light emitting unit and a light receiving unit is arranged on both sides of the ring. The light emitted from the light-emitting portion reaches the light-receiving portion through the opening only once during one rotation of the drum 5, and the rotation sensor 19 detects the detection signal (in synchronization with the rotation of the drum 5 based on the light-receiving signal). (Rotation marker) is output.

The water supply pipe 15 connected to the external tap is
It is connected to the outer tank 2 via a water supply valve 16. When the water supply valve 16 is opened, water is supplied to the outer tub 2 through the water supply pipe 15. On the other hand, a drainage pump 18 is provided in a drainage pipe 17 connected to the bottom of the outer tub 2, and water accumulated in the outer tub 2 is discharged to the outside by driving the drainage pump 18.

Next, the electrical configuration and operation of a portion related to dehydration in the washing machine will be described with reference to FIG.
The control unit 20, which is the center of the control, is configured by a microcomputer including a CPU, and functionally includes a central control unit 21, a rotation speed control unit 22, an eccentric load detection unit 23,
It includes an eccentric load determination unit 24 and the like. An operation unit 31 is connected to the central control unit 21, and an instruction to start washing or the like is given through the operation unit 31. The central control unit 21 includes a memory and a timer in which an operation program for performing the dehydration operation is stored in advance, and while executing the operation program, an instruction to start a dehydration process, measurement of a predetermined time, or a target rotation speed. Indicate numerical values such as.

The rotation speed control unit 22 includes a motor drive unit 32
And the rotation speed detector 34 so that the rotation speed of the motor 12 becomes the target rotation speed specified by the central control unit 21. Specifically, the rotation speed control unit 22
The phase control angle is calculated based on the difference between the target rotation speed and the current rotation speed received from the rotation speed detector 34, and is provided to the motor drive unit 32. The motor drive unit 32 includes an inverter drive circuit including a power switching element such as a triac, and controls on / off of the power switching element in accordance with a given phase control angle, so that 100
A V-sine wave alternating current is cut out and supplied to the motor 12 as a drive current.

The motor current detector 33 detects the fluctuation component of the drive current synchronized with the rotation of the drum 5, converts this into a voltage value, and inputs it to the eccentric load detector 23. FIG. 4 is a waveform diagram showing an example of such a fluctuation component of the motor drive current. In the figure, a rotation marker M is a timing at which a signal indicating a break of one rotation cycle of the drum 5 obtained by the rotation sensor 19 is generated. If an eccentric load exists on the drum 5, the motor drive current has a fluctuation component corresponding to the eccentric load as shown in FIG. Since this fluctuation corresponds to the fluctuation of the load torque of the motor 12, the maximum peak appears when the load torque becomes maximum within one rotation period of the drum 5.

FIG. 6 is a view showing a state in which an eccentric load due to the uneven distribution of the laundry exists on the inner peripheral wall of the drum 5. As shown in FIG. 6, when the eccentric load passes through the lowest position of the drum 5 and is going to be lifted upward, the direction of the tangential component of the gravity of the drum 5 acting on the eccentric load is Opposite to the direction of rotation. That is,
Since the above-described component due to gravity acts to decelerate the drum 5, it is necessary to supply a larger drive current to the motor 12 to maintain the same rotation speed. Conversely, when the eccentric load passes through the highest position of the drum 5 and falls, the direction of the tangential component of the gravity of the drum 5 acting on the eccentric load is the same as the rotation direction of the drum 5. That is, in this case, since the above-described component due to gravity acts to accelerate the drum 5, the same rotation speed is maintained by reducing the motor drive current.

In addition, factors such as friction between the main shaft 8 and the bearing 10 also affect the motor drive current. However, since the above-mentioned fluctuation factors due to the eccentric load are the most dominant, generally the eccentric load is When the drum 5 is lifted upward after passing through the lowest position, the motor drive current shows a maximum peak. Conversely, when the eccentric load is reduced after passing through the highest position of the drum 5, the motor drive current shows a minimum peak.

The fluctuation amplitude L of the motor drive current corresponds to the magnitude of the eccentric load (eccentric amount). FIG. 5 is a graph showing an example of the relationship between the fluctuation amplitude L and the amount of eccentricity. The eccentricity can be obtained from the fluctuation amplitude L during the spin-drying process by examining such a relationship in advance by experiment and storing the relationship in a ROM or the like.

That is, when a signal having the waveform shown in FIG.
, Ie, every one rotation period of the drum 5, the maximum peak and the minimum peak are detected. Then, the difference (fluctuation amplitude L) between the maximum and minimum peaks is calculated, and the amount of eccentricity is obtained by referring to the correspondence stored in the ROM. In addition, the timing of the occurrence of the maximum peak (or the minimum peak) (for example, the delay time from the immediately preceding rotation marker M) causes the drum 5
The position of the eccentric load on the inner circumference is detected. The eccentric load determination unit 24 executes a determination process of the eccentric amount and the eccentric position as described later, and provides an appropriate instruction signal to the rotation speed control unit 22 according to the result.

Next, the procedure of the control operation at the time of the dehydration process in the washing machine having the above configuration will be described with reference to the flowchart shown in FIG. In the following description, a numerical value when the inner diameter of the drum 5 is 460 mm is taken as an example. However, when the drum diameter is different, it can be dealt with by appropriately changing the numerical values such as the rotational speeds. That is clear.

Before the start of the spin-drying process, the laundry in the drum 5 absorbs water and is piled up on the bottom of the drum 5. When the dehydration process is started according to an instruction from the central control unit 21, the rotation speed control unit 22 first controls the motor drive unit 32 to perform a loosening operation (step S1). That is,
The rotational speed (here, 60 to 60) that balances the centrifugal force and the gravity acting on the laundry adhered to the inner peripheral wall of the drum 5
A control is performed so that the drum 5 rotates alternately rightward and leftward at predetermined time intervals within a range of a rotation speed (for example, 50 to 55 rpm) lower than about 65 rpm (hereinafter referred to as “balanced rotation speed”). As a result, the laundry is agitated in both the left and right directions in the drum 5, and the entanglement is loosened therebetween. In addition, since air enters the gaps between the laundry items due to the agitation, it is easy for the individual laundry items to peel off from each other.

After performing the loosening operation for a predetermined time, the rotation speed control unit 22 controls the motor drive unit 32 to increase the rotation speed of the drum 5 to 70 rpm by the phase control (step S2). That is, the drum 5 at this time
Is a rotation speed slightly higher than the above-described equilibrium rotation speed. When the rotation speed of the drum 5 is maintained at around 70 rpm, as shown in FIG. 8A, the laundry adhered to the inner peripheral wall of the drum 5 rotates while being stuck to the inner peripheral wall by centrifugal force. Keep doing. On the other hand, since the centrifugal force acting on the laundry located on the inner peripheral side is weak, the laundry is lifted upward by the baffle 9 (omitted in FIG. 8), and falls backward by rotation due to gravity on the way. To do
It becomes a tumbling state.

The eccentric load detecting section 23 detects the position of the eccentric load on the inner periphery of the drum 5 based on the fluctuation component of the motor driving current as described above (step S3), and the eccentric load determining section 24 detects the position. When the eccentric position reaches the upper part of the drum 5 (step S4), an instruction signal is given to the rotation speed control unit 22. That is, when the rotation speed of the drum 5 is 70 rpm
m, the motor drive current fluctuates due to the eccentric load A caused by the uneven distribution of the laundry rotating on the inner peripheral wall surface of the drum 5. As described above, when the eccentric load A passes through the highest position of the drum 5 and falls, the motor drive current shows the minimum peak. Therefore, it is estimated that the eccentric load A has just reached the highest position of the drum 5 just before the motor drive current reaches the minimum peak.

Therefore, the eccentric load determining unit 24 monitors such a change in the motor drive current, and the eccentric load A
An instruction signal is generated when it is determined that the upper portion has been reached. Upon receiving the instruction signal, the rotation speed control unit 22 controls the motor drive unit 32 so as to supply a 100 V full-wave drive current to the motor 12 without performing phase control (step S5). As a result, the rotation speed of the drum 5 increases rapidly. Further, when the rotation speed of the drum 5 reaches around 130 rpm, the rotation speed control unit 22 switches to the phase control and controls the motor drive unit 32 to maintain the rotation speed at 130 rpm (step S6). The rotation speed at this time is a rotation speed at which the centrifugal force acting on all the laundry in the drum 5 is surely larger than the gravity, and a resonance frequency inherent to the drum 5 (here, about 200 rpm).
pm).

As described above, the rotational speed of the drum 5 is set to 70r
When the speed is rapidly increased from pm to 130 rpm, a large centrifugal force also acts on the laundry that has been in the tumbling state in the drum 5, and the laundry adheres to the inner peripheral wall surface of the drum 5. At this time, since the eccentric load A is present on the upper portion of the drum 5, the laundry in the tumbling state is moved to a position near the drum 5 near the eccentric load A as shown in FIG. The eccentric load B is attached to the inner peripheral wall surface. Therefore, by the balance between the eccentric load A and the eccentric load B,
The amount of eccentricity of the entire drum 5 decreases. The timing at which an instruction signal for rapidly increasing the rotation speed of the motor 12 is generated (that is, at which position of the eccentric load A on the drum 5 the instruction signal is generated) is determined in advance by an experiment. It is good to decide the appropriate timing.

When the rotation speed of the drum 5 reaches 130 rpm and is maintained at the rotation speed, the eccentric load detecting unit 2
3 detects the amount of eccentricity based on the fluctuation component of the motor drive current (step S7). Then, the eccentric load determination unit 24
Determines whether the amount of eccentricity is equal to or less than a specified value (step S8). The specified value is appropriately determined in advance based on the maximum allowable eccentric amount such that the vibration amplitude of the outer box 1 or the outer tub 2 during the high-speed spinning operation falls within the allowable range. Therefore, when it is determined in step S8 that the amount of eccentricity is equal to or smaller than the specified value, it can be determined that the vibration is small even if the state shifts to the high-speed spinning rotation in that state. Then, proceed to step S9,
The rotation speed control unit 22 controls the motor drive unit 32 so as to increase the rotation speed of the drum 5 to a high-speed spinning rotation speed (for example, 1000 rpm).

When the drum 5 rotates at a high spin-dry speed, the water contained in the laundry is discharged from the laundry by centrifugal force and scattered to the outer tub 2 through the water holes 6. When a predetermined time elapses after shifting to the high-speed dehydration rotation speed (step S10), the central control unit 21 instructs the rotation speed control unit 22 to stop the rotation of the motor 12. As a result, the drum 5 stops, and the dewatering process ends. At the time of high-speed dehydration operation, the rotation speed of the drum 5 is set according to a washing course specified by the user (for example, a blanket washing course, a dry-only clothes washing course, etc.) in order to protect laundry that is liable to damage the cloth. The upper limit may be limited to 1000 rpm or less (for example, 800 rpm).

On the other hand, if it is determined in step S8 that the amount of eccentricity exceeds the specified value, the rotation speed control unit 22 receives the result of this determination and drives the motor to reduce the rotation speed of the drum 5. The section 32 is controlled. Then, returning to step S1, the above-described loosening operation is performed again.

Thus, in the washing machine of this embodiment,
The balance of the laundry is adjusted with a high probability, and it is possible to shift to the high-speed spin-dry rotation in a state where the eccentric load of the drum 5 is surely reduced.

Since the centrifugal force acting on the laundry depends on the distance between the laundry and the axis of rotation of the drum 5, the rotation speed of the drum 5 for adjusting the balance changes according to the drum diameter and the like. There is a need. Therefore, by experiment in advance,
A rotation speed at which the best balance adjustment can be performed on the drum 5 is determined in advance. In addition, these numerical values need not always be fixed, and for example, a configuration is adopted in which an appropriate value is selected according to the amount (load amount) of the laundry stored in the drum 5 and the control is executed. Is also good.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a configuration of an embodiment of a washing machine provided with a drum type centrifugal dehydrator of the present invention.

FIG. 2 is a sectional view taken along line aa of the washing machine of FIG. 1;

FIG. 3 is an electrical configuration diagram of a dehydration-related portion of the washing machine in FIG. 1;

FIG. 4 is a waveform diagram showing an example of a fluctuation component of a motor current due to an eccentric load.

FIG. 5 is a graph showing an example of the relationship between the fluctuation amplitude of the motor current and the amount of eccentricity.

FIG. 6 is a schematic cross-sectional view of a drum for explaining a change in motor current due to an eccentric load.

FIG. 7 is a flowchart showing a control operation at the time of a spin-drying process in the washing machine of the present embodiment.

FIG. 8 is a schematic cross-sectional view of a drum for explaining the arrangement of laundry during a spin-drying process in the washing machine of the embodiment.

[Explanation of symbols]

 2 ... Outer tank 5 ... Drum 9 ... Baffle 19 ... Rotation sensor 20 ... Control unit 21 ... Central control unit 22 ... Rotation speed control unit 23 ... Eccentric load detection unit 24 ... Eccentric load determination unit 32 ... Motor drive unit 33 ... Motor current Detector 34: Rotation speed detector

Continued on the front page (72) Inventor Naoki Hayashi 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Inside Sanyo Electric Co., Ltd. (72) Inventor Kenji Nakagawa 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (5)

[Claims] 1. A drum-type centrifugal dewatering device for dewatering laundry contained in a drum by rotating the drum at a high speed about a horizontal axis, comprising: a) a motor for rotating and driving the drum; and b) a drum. An eccentric load detecting means for detecting the eccentric load of the drum; and c) a first speed slightly higher than a rotation speed at which the centrifugal force and the gravity acting on the laundry adhered to the inner peripheral wall surface of the drum are substantially balanced.
When the eccentric load detected by the eccentric load detecting means reaches the upper part of the drum, the centrifugal force acting on all the laundry in the drum becomes larger than gravity when the drum is rotated at the rotation speed of And a rotation control means for controlling the motor so as to rapidly increase the rotation speed of the drum to the rotation speed of 2. 2. The drum type centrifugal dewatering apparatus according to claim 1, wherein the second rotation speed is lower than the inherent resonance frequency of the drum. 3. A deciding means for judging the magnitude of the eccentric load, wherein the rotation control means determines that the eccentric load is equal to or less than a predetermined value when the drum is rotating at a second rotation speed. 3. The drum type centrifugal dewatering apparatus according to claim 2, wherein when it is determined that the rotation speed of the drum is increased, the motor is controlled to increase the rotation speed of the drum to a high speed. 4. The drum type centrifugal dehydrator according to claim 1, wherein said eccentric load detecting means detects an eccentric load based on a change in a driving current of a motor. 5. The rotation control means performs a left-right reversal operation at a rotation speed such that a centrifugal force acting on all the laundry is smaller than gravity before rotating the drum at the first rotation speed. The drum type centrifugal dehydrator according to any one of claims 1 to 4, wherein the motor is controlled as described above.