JP3143355B2 - Centrifugal dehydrator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dewatering basket in which laundry such as clothes is accommodated, and the dehydration basket is rotated at a high speed about a rotating shaft to remove the solvent for dehydrating or washing the laundry. The present invention relates to a centrifugal dehydrator for performing a liquid.

[0002]

2. Description of the Related Art A drum-type centrifugal dehydrator has a structure in which washed clothes are housed in a basket-shaped drum, and the drum is rotated at a high speed about a horizontal axis. One of the major problems with this centrifugal dehydrator is that when the drum is rotated at high speed while the clothes are not evenly distributed on the inner peripheral wall of the drum, abnormal vibration occurs due to imbalance in the mass distribution around the rotation axis. Or abnormal noise.

[0003] A centrifugal dehydrator for solving this problem has been conventionally proposed. For example, in a centrifugal dewatering method described in Japanese Patent Application Laid-Open No. 6-254294, a method is disclosed in which clothes in the drum are uniformly dispersed and arranged by low-speed drum rotation before performing a dehydration operation by high-speed drum rotation. Have been. More specifically, a two-stage drum rotation control in which the drum is rotated at a low speed for a very short time and then at a speed slightly higher than the rotation speed but sufficiently lower than the rotation speed during the spin-drying operation. By combining the above, the dispersion of clothes inside the drum is promoted.

Further, in this prior art, a vibration monitoring sensor is installed on a pedestal portion of the apparatus as a means for detecting an unbalanced load generated because clothes are not uniformly distributed inside the drum, and the rotational speed is high. When the vibration monitoring sensor detects abnormal vibration when rotating the drum, the rotational speed is reduced.

[0005]

However, even with the drum rotation control method as in the above-mentioned prior art, uniform dispersion of clothes cannot always be achieved with a single low-speed rotation of the drum. Therefore, if the vibration is large when the drum is rotated at a high speed after the drum is rotated at a low speed and the dispersion is attempted, it is necessary to perform the dispersion again by rotating the drum at a low speed. In this way, if it becomes necessary to repeat the dispersion by the low-speed rotation of the drum and the detection of the unbalanced load a plurality of times, there arises a problem that a long time is required for the dewatering process.

The present invention has been made to solve such a problem, and an object thereof is to surely detect an eccentric load caused by uneven distribution of clothes at the time of low-speed rotation of a drum and to detect unevenly distributed clothes in a drum. It is an object of the present invention to provide a centrifugal dewatering device capable of avoiding the occurrence of abnormal vibrations and abnormal noises and dispersing water efficiently by uniformly dispersing them on the peripheral wall surface.

[0007]

When a rotating body having an eccentric load is driven to rotate at a constant rotation speed, the load torque fluctuates with rotation, and the motor current flowing through the motor fluctuates. . At that time, the lower the rotation speed, the more noticeable the fluctuation of the motor current,
It becomes easy to detect the fluctuation. However,
The unbalanced load of the drum containing the clothes can be detected only in a state where the clothes rotate while being pressed against the inner peripheral wall of the drum, that is, in a state where the centrifugal force acting on the clothes exceeds gravity. . Thus, in the present invention, when the drum is rotated at a rotation speed slightly higher than the rotation speed at which the centrifugal force and the gravity acting on the clothes inside the drum are balanced, the fluctuation of the motor current is detected, and based on this, To determine the eccentric load.

On the other hand, when the drum is rotated at a rotation speed slightly lower than the rotation speed at which the centrifugal force and the gravity acting on the clothes in the drum are balanced, the dispersion of the clothes can be promoted. Now, the mass is W [kg], the radius of rotation from the center of the drum to the clothing is r [m], and the angular velocity of the drum is ω [rad / s].
, The rotational centrifugal force acting on the clothes P [kg · m / s ² ]
Can be expressed by the following equation (1). P = r · ω ² · W (1) That is, since the rotating centrifugal force acting on the garment located closer to the center of the drum and having a smaller radius r is smaller, the centrifugal force acting on the garment inside the drum and the gravity are smaller. As the rotation speed is gradually reduced from the equilibrium rotation speed, the garments overlap and fall first from the clothes located near the center of the drum. Therefore, by appropriately selecting the rotation speed of the drum according to the diameter of the drum, it is possible to drop and disperse only the overlapping garments, which are factors of the uneven load.

In view of the above, according to the present invention, while the rotational speed of the drum is changed near the rotational speed at which the centrifugal force acting on the clothes inside the drum and the gravity balance, the determination of the uneven load and the dispersion of the clothes are performed. I do it.

A first centrifugal dehydrator according to the present invention accommodates laundry such as clothes in a basket-shaped drum, and rotates or rotates the drum about a horizontal axis to dehydrate or wash the laundry. In a centrifugal dehydrator that removes solvent for
A motor for driving the drum to rotate, detecting means for detecting a current flowing through the motor, and detecting whether the current fluctuates in synchronization with a rotation cycle of the drum to determine whether an uneven load inside the drum is large. and a determination means for determining whether the laundry in said drum overlaps
Rotated while pressed against the inner wall of the drum
The centrifugal force acting on the laundry inside the drum
At the rotation speed that is rotated while slightly overcoming gravity
Rotate the drum at a certain first speed, when the rotation
When the determining unit determines that the eccentric load is large.
Near the center of the drum in the overlapping laundry
Laundry that is placed in the stack and causes uneven load
Drop by gravity on the way and stick to the inner peripheral wall of the drum
Rotate the laundry so that it does not drop by centrifugal force.
Reduce the speed so that the centrifugal force and gravity balance
At a second rotational speed, which is a slightly slower rotational speed.
Rotate to distribute the laundry evenly on the inner peripheral wall of the drum
When the drum is rotated at the first rotation speed
When the determining unit determines that the unbalanced load is small
The drum is rotated at a rotation speed at which dehydration or drainage operation is performed.
It is characterized by further comprising a rotation speed control means for rotating.
And

The determining means in the present invention detects that the fluctuation component of the motor current is synchronized with the rotation cycle of the drum,
When the fluctuation of the motor current is synchronized with the rotation cycle, it is determined that the unbalanced load inside the drum is large.

Therefore, according to the present invention, it is possible to reliably determine the magnitude of the eccentric load without performing the high-speed rotation of the drum that causes the occurrence of abnormal vibration.

[0013]

The first rotation speed is a rotation speed slightly higher than the rotation speed at which the centrifugal force acting on the clothes inside the drum and the gravity balance, and is a rotation speed at which it is easy to detect a change in the motor current. is there. When the drum is rotated at the first rotation speed, it is determined that the magnitude of the unbalanced load exceeds the allowable value when the fluctuation of the motor current is synchronized with the rotation cycle of the drum. In that case, the rotation speed control means performs speed control so as to reduce the rotation speed of the drum to the second rotation speed. When the drum is rotated at the second rotation speed, the laundry inside the drum is carried upward from the bottom in a state of being in close contact with the inner peripheral wall of the drum as the drum rotates, but since the gravity is larger than the centrifugal force, The laundry near the center of the drum overlaps and falls during rotation. Thus, the laundry is evenly distributed inside the drum.

After the drum has been rotated at the second rotation speed for a predetermined time, the magnitude of the eccentric load is determined again, and if the eccentric load has been eliminated, dehydration or drainage by predetermined high-speed rotation is performed. Operation is performed.

Therefore, according to the present invention, the unbalanced load inside the drum is reliably detected before the dewatering or draining operation is performed, and when the unbalanced load is large, the laundry is effectively and uniformly dispersed. After the operation is performed, a spin-drying or draining operation by high-speed rotation of the drum is performed. Therefore, it is possible to avoid occurrence of abnormal vibration and abnormal noise due to imbalance in the arrangement of the laundry stored in the drum. Further, since the unbalanced load is determined when the drum rotates at a low speed, even if the unbalanced load is not eliminated by one decentralized operation, the result is promptly detected and the decentralized operation is performed again. be able to. Therefore, it is possible to prevent the dehydration or liquid removal operation from being lengthened, and to efficiently perform the dehydration or liquid removal.

Preferably, when the fluctuation of the current is synchronous with the rotation cycle of the drum and the amplitude of the fluctuation is equal to or larger than a predetermined threshold, the determining means increases the unbalanced load inside the drum. Is determined. As a result, an effect that the determination of the unbalanced load can be performed more reliably can be expected.

[0018]

In the second centrifugal dehydrator, when the determining means determines that the unbalanced load inside the drum is equal to or more than the allowable value, the rotational speed corresponding to the second rotational speed in the first centrifugal dehydrator is used. Rotates the drum for a predetermined time. Due to the rotation of the drum, the laundry is uniformly dispersed in the drum.

[0020]

[0021]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an electric system of a centrifugal dehydrator in a drum type washing machine according to an embodiment of the present invention, FIG. 2 is a vertical sectional view of a drum type washing machine having the centrifugal dehydrator according to the embodiment, and FIG. FIG. 4 is a flowchart for explaining a procedure of drum rotation control in an example.
FIG. 5 is a diagram illustrating an example of a motor current for determining an unbalanced load in the present embodiment, and FIG. 5 is a schematic diagram illustrating a movement state of clothing inside the drum in the present embodiment.

First, the overall structure of the drum type washing machine will be described with reference to FIG. An outer tub 52 is arranged inside an outer box 50 of the drum type washing machine main body, and a drum 54 for storing clothes is supported by a main shaft 58 and installed inside the outer tub 52. A water passage hole 56 is formed in the peripheral wall of the drum 54, and the washing water supplied to the outer tub 52 flows into the drum 54 through the water passage hole, and water dehydrated from clothes in the drum 54 is removed. It is discharged to the outer tank 52. Main shaft 58
Is held by a bearing 60 mounted on the outer tub 52, and a main pulley 62 is attached to a tip of the bearing 60.
A motor 22 for rotating and driving the drum 54 is disposed below the outer tub 52, and a motor pulley 66 is attached to a rotating shaft of the motor 22. Motor pulley 66
Is transmitted to the main pulley 62 through the V-belt 64 to rotate the main shaft 58.

The washing water is supplied from the outside to the outer tank 52 through a water supply port 70, and the amount of the water is adjusted by a water supply valve 72. The washed water is discharged through the discharge port 74. The discharge port 74 is opened and closed by a discharge valve 76. A drive voltage is applied to the motor 22 from the circuit unit 78. The circuit unit 78 includes a control unit 10 and an inverter control circuit 20 which will be described later. Rotation sensor 24
Is composed of a light-emitting unit installed outside the outer tub 52 with the main pulley 62 interposed therebetween and a light-receiving unit installed inside the outer box 50, and serves to detect the rotation speed and the rotation position of the drum 54. .

Next, the electrical configuration and operation of the circuit section 78 of FIG. 2 will be described with reference to FIG. The control unit 10 mainly composed of a microcomputer is a central control unit 1
2. It comprises a rotation speed control unit 14, an unbalanced load determination unit 16 and a memory 18. Further, the unbalanced load determination unit 16 includes a peak value detection unit 161, an amplitude measurement unit 162, a position determination unit 16
3, a comparison unit 164 and an AND gate 165. In addition to the control unit 10, an inverter control circuit 20 for applying a drive voltage to the motor 22, a rotation sensor 24, and a motor current detection circuit 26 are provided.

Hereinafter, the operation of the electric system will be described. The memory 18 stores in advance an operation program for performing each of the washing and dehydration steps. When the operator performs a key operation from an operation unit (not shown) to select a dehydration process mode, for example, a type of fiber of clothing to be dehydrated, and instructs a start of the dehydration process, the central control unit 12 executes a corresponding operation program. Is read from the memory 18 and this operation program is executed to advance the dehydration process.

The rotation speed control unit 14 outputs a rotation speed designation signal of the motor 22 to the inverter control circuit 20 based on a value previously incorporated in the operation program. The inverter control circuit 20 converts the rotation speed designation signal into a pulse width modulation (PWM) signal, and applies a drive voltage corresponding to the PWM signal to the motor 22. Therefore, the rotation speed control unit 14 and the inverter control circuit 20 function as a rotation speed control unit.

The motor current flowing when the motor 22 rotates is detected by the motor current detection circuit 26 and is input to the unbalanced load determination unit 16. The motor current detection circuit 26 converts the motor current into a voltage proportional to the effective value by a current / voltage conversion circuit. FIG. 4 shows an example of the waveform of the motor effective value current detected by the motor current detection circuit 26. FIG. 4A shows an example where the eccentric load is large, and FIG. 4B shows an example where the eccentric load is small. The detection signal from the motor current detection circuit 26 and the rotation sensor 2
4 is input. The rotation marker signal is a pulse signal obtained each time the drum 54 makes one rotation.

The peak value detecting section 161 detects the interval between the rotation marker signals, that is, the positive peak and the negative peak of the motor current fluctuation within one rotation of the drum 54 every one rotation period. The positive peak and the negative peak are input to the amplitude measuring unit 162 and the position determining unit 163. The position determination unit 163 compares the positive peak position and the negative peak position obtained each time the drum 54 makes one rotation with each rotation of the drum 54, and determines whether the position has periodicity. . That is, it is determined whether or not the fluctuation of the motor current is synchronized with the rotation cycle of the drum 54. For example, in the motor current shown in FIG. 4A, a positive peak and a negative peak are generated at substantially equal positions from the rotation marker signal. Therefore, it is determined that the fluctuation of the motor current is synchronized with the rotation cycle. On the other hand, in the motor current shown in FIG. 4B, the positive peak and the negative peak are respectively generated at positions irrelevant to the rotation marker signal.
Therefore, it is determined that the fluctuation of the motor current is not synchronized with the rotation cycle of the drum 54.

The amplitude measuring section 162 measures the amplitude value of the motor current fluctuation for each rotation from the positive peak value and the negative peak value obtained each time the drum 54 makes one rotation. The measurement result is compared with a predetermined threshold value in the comparing section 164, and a signal of a positive level is output when the amplitude value is larger than the threshold value. For example, the threshold is set as T shown in FIG. In the AND gate 165, the logical product of the result of the determination of the periodicity and the result of the comparison of the amplitude is obtained. Therefore,
When the fluctuation of the motor current is synchronized with the rotation cycle of the drum 54 and the fluctuation amplitude is equal to or larger than a predetermined threshold, for example, when the motor current is as shown in FIG. The gate 165 detects the motor load, that is, the result that the drum 54 has an unbalanced load.
Output to 4. The rotation speed controller 14 receives the result and outputs a rotation speed designation signal for rotating the motor 22 as described later.

Hereinafter, the control procedure of the dewatering process will be described with reference to FIGS. 1, 4 and 5 along the operation flowchart of FIG. When the dehydration process is started, first, a medium-speed dehydration rotation is performed (Step S10). The medium-speed dehydration rotation is a dehydration operation in a range of rotation speed such that the vibration of the drum main body can be small even when the drum 54 has an uneven load. For example, when the drum diameter is 700 [mm], the rotation is performed. The speed is about 500 [rpm]. Rotation speed control unit 1
4 designates this rotation speed to the inverter control circuit 20,
The inverter control circuit 20 applies a drive voltage corresponding to the rotation speed to the motor 22.

The clothes in the drum 54 are dewatered to some extent by the rotation at the medium speed. First drum 54
Since a large amount of water is soaked in the clothes inside, the weight balance of each clothes before dehydration and the weight balance of each clothes after dehydration do not always match. Therefore, by performing the medium-speed dehydration rotation so that the weight of each garment inside the drum 54 is in a state close to the state after the final dehydration, it is possible to detect the state of the uneven load as accurately as possible.

The water permeating the clothes inside the drum 54 is dehydrated to some extent by the medium-speed dehydration rotation, and the clothes are rotated while being attached to the inner peripheral wall surface of the drum 54. Next, the drum 54 is rotated at a low speed to determine the unbalanced load (Step S12). That is, the rotation speed control unit 14 outputs a predetermined low rotation speed (first rotation speed) N1 as a rotation speed designation signal to the inverter control circuit 20, and the inverter control circuit 20 determines that the rotation speed of the drum 54 is the first rotation speed. A drive voltage is applied to the motor 22 so as to reach the rotation speed N1. Here, the first rotation speed N1 is a rotation speed at which the centrifugal force acting on the clothes inside the drum 54 slightly exceeds the gravity, and is appropriately determined according to the drum diameter. For example, if the drum diameter is 70
At 0 [mm], the first rotation speed N1 is 55 [rpm].
Degree.

When the rotation speed of the drum 54 is equal to the first rotation speed N
When the value reaches 1, the unbalanced load determination unit 16 determines the unbalanced load based on the motor current detected by the motor current detection circuit 26 as described above (step S14).

If it is determined that the unbalanced load is large, the rotation speed is further reduced and a low-speed rotation for dispersing the clothes is performed (step S18). That is, the rotation speed controller 14 outputs a predetermined low rotation speed (second rotation speed) N2 to the inverter control circuit 20 as a rotation speed designation signal, and the inverter control circuit 20 determines that the rotation speed of the drum 54 is the second rotation speed. A drive voltage is applied to the motor 22 so as to reach the speed N2. Here, the second rotation speed N 2
4 is a rotation speed slightly lower than the rotation speed at which the centrifugal force acting on the clothes inside and the gravity are balanced, and is appropriately determined according to the drum diameter similarly to the first rotation speed N1. For example, when the drum diameter is 700 mm, the second
Is about 50 [rpm].

When the rotation speed is the first rotation speed N1, the clothes in the drum 54 are rotated in a state where the clothes are pressed against the inner peripheral wall of the drum 54 while the clothes are overlapped as shown in FIG. When the rotation speed is reduced to the second rotation speed N2 from this state, as shown in FIG. 5B, the centrifugal force acting on one of the overlapping clothes near the center of the drum is smaller than the gravity, This garment falls during rotation. On the other hand, since the centrifugal force acting on the clothes stuck to the inner peripheral wall of the drum 54 is larger than the gravity, the clothes continue to rotate without falling. As a result, as shown in FIG. 5C, all the clothes are almost evenly distributed on the inner peripheral wall surface of the drum 54, and the unbalanced load is eliminated.

After performing the low-speed rotation at the second rotation speed N2 for a predetermined time, the rotation-speed control unit 14 performs the low-speed rotation at the first rotation speed N1 again in order to determine the unbalanced load. Is performed (step S12). At this time, the unbalanced load determination unit 16 determines whether the uneven distribution of the clothing has been eliminated.

If it is determined in step S14 that the unbalanced load is small, then high-speed spinning is performed (step S16). That is, when the rotation speed control unit 14 receives the determination result that the unbalanced load is small from the unbalanced load determination unit 16, the rotation speed control unit 14 outputs the third rotation speed N3 as a rotation speed designation signal. A drive voltage is applied to the motor 22 so that the rotation speed becomes the third rotation speed N3. Here, for example, the third rotation speed N3 is
It is about 700 [rpm]. This third rotation speed N3
Is a value according to the dehydration process mode specified by the operator, and is a value that differs depending on the type of the fiber of the clothing and the like. By rotating the drum 54 at the third rotation speed N3 for a predetermined time, complete dehydration is performed.

In the above embodiment, before determining the eccentric load,
The medium-speed spin-drying rotation (Step S10) for performing a certain degree of spin-drying has been performed.
You may start from 2.

Although the above embodiment has been described with reference to a drum-type washing machine, it is apparent that the present invention can be applied to a washing machine using a petroleum-based solvent or the like, that is, a dry cleaner.

Further, as a method of detecting the uneven distribution of clothes inside the drum, for example, a mercury switch or an acceleration sensor may be used in addition to the method of detecting the motor current.

[Brief description of the drawings]

FIG. 1 is an electric block diagram of a centrifugal dehydrator in a drum type washing machine according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a drum type washing machine including the centrifugal dehydrator according to the embodiment.

FIG. 3 is a flowchart for explaining a procedure of drum rotation control in the embodiment of the present invention.

4A and 4B are diagrams illustrating an example of a motor effective value current for determining an unbalanced load according to the present embodiment, in which FIG. 4A illustrates an example in which the unbalanced load is large, and FIG. .

FIGS. 5A and 5B are schematic diagrams illustrating a movement state of clothing inside the drum in the present embodiment, in which FIG. 5A illustrates a state in which the centrifugal force acting on the clothing rotates the drum at a rotational speed against the gravity, and FIG. ) Is a state in which the clothes are dispersed, and (c) is a state in which the clothes are dispersed and the uneven load is eliminated.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Control part 14 ... Rotation speed control part (rotation speed control means) 16 ... Uneven load determination part (judgment means) 20 ... Inverter control circuit (rotation speed control means) 22 ... Motor 26 ... Motor current detection circuit (detection means) 54 ... Drum

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-250196 (JP, A) JP-A-4-166192 (JP, A) JP-A-1-268597 (JP, A) JP-A-3- 215289 (JP, A) JP-A-5-31294 (JP, A) JP-A-5-184769 (JP, A) JP-A-54-70656 (JP, A) JP-B-45-38794 (JP, B1) JP-B-47-38114 (JP, B1) JP-B-63-35269 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) D06F 49/04 D06F 49/00 D06F 33/02

Claims (2)

(57) [Claims] 1. A centrifugal dehydrator for storing laundry such as clothes in a basket-shaped drum and rotating the drum about a horizontal axis to dehydrate the laundry or remove a solvent for washing. A) a motor for rotating and driving the drum; b) detection means for detecting a current flowing in the motor; andc) detecting that the current fluctuates in synchronization with a rotation cycle of the drum. and a determining means for determining whether the offset load of the internal drum is large, the drum circumference remains laundry in said drum is overlapped
The centrifugal force acting on the laundry inside the drum slightly exceeds gravity so that it rotates while being pressed against the wall.
That state is rotated the drum at a first rotational speed is a rotational speed that is rotated by a drum center of the said during rotation when it is determined that offset load is large by the determining means, overlapping laundry
Washing that is located close to the
The rinse is dropped by gravity during rotation, and the inner peripheral wall of the drum is
Do not drop the laundry stuck on to the centrifugal force
Sea urchin, centrifugal force and thus reduce the rotational speed and the gravitational force is balanced
The drum is rotated at a second rotation speed, which is a rotation speed slightly lower than the rotation speed, and the laundry is placed on the inner peripheral wall surface of the drum.
Evenly decentralized, when it is determined that offset load is small by the determining means when rotating the drum at a first rotation speed, rotate the drum at a rotating speed of performing the dehydration or dehydrogenation liquid operation A centrifugal dewatering device, further comprising a rotation speed control means for causing the rotation speed to be controlled. 2. The method according to claim 1, wherein the variation of the current is synchronized with a rotation cycle of the drum and the amplitude of the variation is equal to or greater than a predetermined threshold value, and the determination unit determines that the uneven load inside the drum is large. The centrifugal dehydration apparatus according to claim 1, wherein: