KR100305256B1 - Drum type washing machine - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum type washing machine, wherein during the dehydration operation, before the predetermined dehydration rotation speed (N ₀ ) is reached, the rotation speed is lower than the dehydration rotation speed (N ₀ ), respectively. At least once, the control means 10 is controlled to have a step of rotation speed N ₂ lower than the rotation speed N ₁ of the previous stage, and to achieve low vibration by lowering the unbalance of the laundry before reaching a predetermined dewatering rotation. It is characterized by.

Description

Drum-type washing machine {DRUM TYPE WASHING MACHINE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum type washing machine, and more particularly to a technique for reducing unbalance of laundry in a dewatering stroke.

As a conventional drum type washing machine, there is one shown in FIG. 8, for example. In FIG. 8, reference numeral 1 denotes an outer case, and the outer case 1 includes a water tank 2 supported by the suspension 4, and the washing and dehydration of the water tank 2 freely rotatably supported on a horizontal axis. The drum 3 is provided. The driving motor 5 is attached to the lower side of the water tank 2 so that rotation of the driving motor 5 is transmitted to the washing-and-dehydrating drum 3 through pulleys, belts, and the like (not shown).

In the dehydration operation, the washing and dehydrating drum 3 is rotated by the drive motor 5 at a predetermined dehydration rotation speed N ₀ , and the laundry 6 is washed and dehydrated drum 3 by centrifugal force. It is pressed on the inner circumferential surface of and dehydration is performed. At this time, the laundry 6 is rarely distributed in a constant shape on the inner circumferential surface of the washing and dehydrating drum 3, thereby causing an unbalanced portion by the laundry 6. The centrifugal force of this unbalanced part causes vibration, and the water tank 2 vibrates, and the main body vibrates through a vibration transmission path such as the suspension 4. As such, the drum type washing machine in which the washing and dewatering drum 3 rotates about a horizontal axis with respect to the bottom surface 7 is unbalanced of the laundry 6 during dehydration. Vibrate in a vertical plane. For this reason, the vibration transfer force to the bottom surface 7 is larger than that of a washing machine (two tank washing machine, a vortex automatic washing machine, etc.) in which a dehydration tank rotates around a vertical shaft, and thus, a drum washing machine needs to be reinforced. There may be cases. Moreover, low vibration is mentioned as one of the important subjects of a drum type washing machine, such as making a main body weight heavy, in order to suppress the vibration which a main body becomes large because a vibration is large. As the most effective means of reducing the vibration of the main body, it is conceivable to make the unbalance of the laundry 6 which causes the vibration very small before reaching the predetermined dewatering rotation speed N ₀ .

On the other hand, there is a conventional technique disclosed in Figs. 9 and 10 and Japanese Patent Laid-Open No. 54-18163. In the prior art, when the washing and dewatering drum 3 is stopped before the dewatering rotation, as shown in Fig. 9, the laundry 6 is in a state gathered at the bottom, and thus the dewatering rotation speed N ₀ is maintained. As early as possible, the laundry 6 remains in an inclined state and is likely to become a large unbalance. For this reason, as shown in the time chart of FIG. First, in order to loosen the laundry 6, the washing and dehydrating drum 3 is repeatedly rotated forward, half and stop at about 50 rpm. Next, the washing-and-dehydrating drum 3 is rotated at a rotational speed N _{P such that the} centrifugal acceleration (= R · ω ² ) almost coincides with gravity to reach the dewatering rotational speed N ₀ after a predetermined time. The unbalance of the laundry 6 is made very small before reaching a predetermined dewatering rotation.

However, such a dehydration control method of the conventional drum type washing machine starts the laundry 6 because the laundry 6 starts to rotate in a state where the laundry 6 is collected under the washing and dehydrating drum 3 at the rotational speed N _P. The difference in the load of the drive motor 5 at the time of rotating upward and downward respectively is large. For this reason, the rotation speed (rotation angle speed (ω _1U )) when rotating the laundry 6 upward is slightly lower than the rotation speed (rotation angle speed (ω _1D )) when rotating the downward (ω _1U < ω <ω _1D ) and the centrifugal acceleration tends to be smaller than gravity. In addition, as shown in FIG. 9, since the laundry 6 is gathered at the bottom, the centrifugal acceleration due to the rotation of the washing and dehydrating drum 3 is small near the center of the laundry 6, so that the laundry is not lifted upward. Only the bottom of the dehydration drum (3) is rotated. As described above, the laundry 6 does not adhere to the inner circumferential surface of the washing and dewatering drum 3 despite the rotation speed at which the gravity and the centrifugal acceleration due to the rotation of the washing and dewatering drum 3 coincide with each other. It becomes in the state like FIG.11 (a), and it becomes easy to produce the unbalance of the laundry 6 in A part at predetermined | prescribed spin speed N _o . In addition, in order to make the laundry 6 adhere to the inner circumferential surface of the washing-and-dehydrating drum 3 at the rotational speed N _P , the rotational speed N is caused by the above-described phenomenon in the state in which the laundry 6 is collected at a lower side. _{It is necessary to set P} ) to the number of revolutions with centrifugal acceleration larger than gravity, and the centrifugal acceleration and gravity coincide with the radius Ri ₂ shown in Fig. 11B (Ri ₂ ω ² = g). As a result, since the laundry 6 having a radius Ri ₂ or more is attached to the inner circumferential surface of the washing and dehydrating drum 3 and becomes a distribution shown in FIG. 11B, there is a problem that an unbalanced part such as part B remains. .

The present invention has been made in view of the above problems, and an object of the present invention is to provide a drum type washing machine capable of realizing low vibration by reducing the unbalance of laundry causing vibration before entering a dehydration stroke at a predetermined dehydration rotation speed.

1 is a view showing an internal configuration of an embodiment of a drum type washing machine according to the present invention;

2 is a block diagram showing a configuration of a control system in the embodiment;

3 is a time chart at the time of the dehydration stroke of the embodiment;

4 is a view for explaining the state of the laundry in the washing and dehydrating drum at the rotational speed (N ₁ ) and the rotational speed (N ₂ ) in the embodiment;

FIG. 5 is a view showing a state in which laundry is attached to the inner circumferential surface of the dewatering and dewatering drum uniformly in the embodiment;

FIG. 6 is a view for explaining a state of laundry in a washing-and-dehydrating drum at rotational speed N ₁ and rotational speed N ₂ when the unbalance of laundry is large in the above embodiment; FIG.

7 is a flowchart for explaining an operation control example in the dehydration stroke in the embodiment;

8 is a view showing the internal configuration of a conventional drum type washing machine,

FIG. 9 is a view showing a state of laundry when the washing and dewatering drum is stopped in the conventional art; FIG.

10 is a time chart during the dehydration stroke of the prior art, and

It is a figure for demonstrating the state of the laundry in a washing | cleaning and a dehydration drum at the time of a dehydration stroke in the said prior art.

* Explanation of symbols for the main parts of the drawings

3: washing and dewatering drum 5: driving motor

6: laundry 10: control circuit (control means)

C: Unbalanced part of laundry R _i : Inner radius of laundry

In order to solve the above problems, the invention described in claim 1 has a plurality of steps of rotating each of the washing and dewatering drums at a lower rotation speed than the predetermined dehydration rotation speed before reaching a predetermined dewatering rotation speed in the dehydration operation of the laundry. And a control means for controlling at least one of the plurality of steps to have a step in which the rotation speed is lower than the rotation speed in the previous step. With this configuration, if there is an unbalanced part of the laundry attached to the inner circumferential surface of the washing-and-dehydrating drum at the rotational speed of the previous stage, the laundry of the unbalanced portion is raised to the upper side and the drop is repeated at the rotational speed of the rotational speed decreasing step. By this repetition, the laundry of the unbalanced part is released, and the laundry can be uniformly attached to the inner circumferential surface of the washing and dewatering drum before the dewatering stroke at the predetermined dewatering rotation speed, thereby making it possible to reduce the unbalanced part.

The invention according to claim 2 is the drum type washing machine according to claim 1, wherein the rotation speed of the previous step is "N ₁ ", the rotation speed of the step of decreasing the rotation speed is "N ₂ ", and the rotation speed (N ₁ ) Centrifugal force at an average inner circumferential radius of the laundry attached to the inner circumferential surface of the washing and dehydrating drum at the time of “CF ₁ ”, and an average inner circumferential radius of the laundry attached to the inner circumferential surface of the washing and dehydrating drum at the rotational speed (N ₂ ). When the centrifugal force of "CF ₂ " and the gravitational constant "G", CF ₁ > 1G and CF ₂ ≤ 1G. With this configuration, the laundry is attached to the inner circumferential surface of the washing-and-dehydrating drum at the rotational speed N ₁ , and if the laundry has an unbalanced portion in the attached state, only the laundry of the unbalanced portion at the rotational speed N ₂ is Falls under the influence of gravity near the top. As a result, the laundry uniformly adheres to the inner circumferential surface of the washing and dewatering drum, thereby reducing the unbalanced portion.

According to the invention described in claim 3, in the drum type washing machine according to claim 1 or 2, the rotation speed N ₁ of the previous step and the rotation speed N ₂ of the step of decreasing the rotation speed are determined by the amount of the laundry. The point is to decide. According to this configuration, the inner circumferential radius of the laundry when the laundry is uniformly attached to the inner circumferential surface of the washing and dewatering drum differs depending on the amount of the laundry. The larger the amount of the laundry, the smaller the inner circumference radius, and the smaller the amount of the laundry, the larger the inner circumference radius. Therefore, when the amount of the laundry is large, the rotational speed N ₁ , N ₂ is increased by the smaller inner radius of the laundry so as to match gravity at the inner radial position thereof, and when the amount of the laundry is small, the rotational speed (N ₁ , N ₂ ) is made small. This makes it possible to stably reduce the unbalance of the laundry.

The invention according to claim 4 is the drum type washing machine according to claim 1 or 2, wherein the rotation speed (N ₁ ) of the previous step and the rotation speed (N ₂ ) of the step of decreasing the rotation speed are the quality of the cloth of the laundry. It is a summary to decide according to. According to this configuration, the inner circumferential radius of the laundry when the laundry is uniformly attached to the inner circumferential surface of the washing and dewatering drum depends on the quality of the cloth of the laundry. The rougher the quality of the cloth, the smaller its inner radius. The softer the quality of the cloth, the larger its inner radius. Therefore, when the quality of the laundry cloth is rough, the rotational speed N ₁ , N ₂ is increased by the smaller inner diameter of the laundry so that its inner circumferential radial position is equal to gravity. Reduce (N ₁ , N ₂ ). This makes it possible to stably reduce the unbalance of the laundry.

The invention described in claim 5 is the drum type washing machine according to claim 1 or 2, wherein the load and torque of the motor driving the washing and dewatering drum at the rotational speed (N ₂ ) of the step in which the rotational speed decreases. The main point is to detect the unbalance of the laundry in the washing and dehydrating drum. With this configuration, when the unbalance of the laundry is large, the rotational unevenness in one rotation of the washing and dewatering drum is increased, and the load torque of the drive motor is changed in the state of large and small unbalance. Therefore, the load torque of the drive motor makes it possible to reliably detect the large unbalance of the laundry.

According to the sixth aspect of the present invention, in the drum type washing machine according to the first or second aspect, the washing in each of the rotational speed N1 of the previous step and the rotational speed N2 of the step in which the rotational speed decreases. The main point is to detect the unbalance of the laundry in the washing-and-dewatering drum by the difference in the load torque of the motor for driving the cumulative dehydrating drum. Can be rotated by this arrangement is unbalanced state as compared to the load torque of the drive motor at the time of (N ₁₎ driving the load torque and the rotational speed of the motor (N ₂₎ when the number of revolutions the fall of the laundry caused (N ₂₎ when The load torque side of the drive motor increases. Therefore, the difference in the load torque of the drive motor at the rotational speed N ₁ and the rotational speed N ₂ makes it possible to more reliably detect the unbalanced state of the laundry.

According to the seventh aspect of the present invention, in the drum type washing machine according to the fifth or sixth aspect, the steps of the rotation speed N ₁ and the steps of the rotation speed N ₂ are repeated until a predetermined unbalance is achieved. Let's make a point. By this structure, the unbalanced state of the laundry can be reduced to a certain amount or less by repeating the operation of the rotation speeds N ₁ and N ₂ .

According to the eighth aspect of the present invention, in the drum type washing machine according to the seventh aspect, when the predetermined unbalance is less than or equal to each other, the predetermined amount is increased by the predetermined amount of the rotational speed N ₁ and the rotational speed N ₂ , respectively. The dehydration rotation speed (N ₀ ) of is set to lower a predetermined amount. This configuration increases the rotational speeds N ₁ and N ₂ to reduce the inner circumferential rotation radius of the laundry that matches the gravity, so that the laundry is strongly pushed by the inner circumferential surface of the washing and dewatering drum, and the predetermined dewatering rotation speed ( By lowering N ₀ ), it is possible to better solve a state in which the occurrence of vibration is suppressed and not below a predetermined unbalance.

Embodiment of the Invention

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on FIG. In addition, in FIG. 1, the thing which is the same as or equivalent to the said apparatus, member, etc. of FIG. 8 attaches | subjects the same code | symbol as the above, and abbreviate | omits the overlapping description. First, the configuration of the drum type washing machine will be described with reference to FIG. 1. In the present embodiment, the control circuit 10 as a control means for controlling the rotation speed of the washing and dehydrating drum 3 in the lower part of the outer case 1 is described. Is arranged, and a rotation sensor (not shown) for detecting the rotation speed of the output shaft is attached to the drive motor 5. In addition, the upper part of the front face of the outer case 1 is provided with key input means, an indicator, etc. which are not shown in figure for performing the following key input. 2 shows a control system. The control circuit 10 includes a calculation unit 11, a storage unit 12, a control unit 13 and a counter unit 14, and includes input signals 15 such as keys and switches, The motor speed signal 16 and the motor load current signal 17 are input. In addition, the control circuit 10 controls the drive motor 5 via the drive circuit 18 and simultaneously controls the display operation of the display 19.

Next, each control method and operation | movement are demonstrated in order.

① to rotate at a number of revolutions predetermined dehydration rotation speed is dehydrated before reaching the (N ₀₎ (N ₀₎ than the number of revolutions of the lower two-stage _{(N 1, N 2 (N} 1> N 2)); the time of 3 As shown in the chart, the washing-and-dehydrating drum 3 was repeatedly rotated forward, stop, half-turn and stop several times at 50 rpm in order to solve the entanglement of the laundry 6 before reaching the predetermined dehydration rotation speed N ₀ . After that, the laundry 6 is rotated at a rotation speed N ₁ that can be attached to the inner circumferential surface of the washing and dehydrating drum 3. Since the laundry 6 at the time of stopping is rotated at the rotational speed N ₁ in a downwardly inclined state, it is necessary to apply a centrifugal force sufficiently larger than gravity, and as described in the prior art, the rotational speed N ₁ The laundry 6 has an unbalanced portion C as shown in FIG. Washing and dehydrating drum more strongly by the dehydration action of the outer circumferential side of the laundry 6 attached to the inner circumferential surface of the washing and dehydrating drum 3 by operating at a rotational speed N ₁ for a predetermined time (20 sec to 30 sec). It is pushed to the inner peripheral surface of (3). Next, as shown in Fig. 5, the inner circumferential radius Ri of the laundry 6 in the abnormal state in which the laundry 6 is uniformly attached to the inner circumferential surface of the washing-and-dehydrating drum 3 next. The centrifugal force at the position drops to a rotational speed N _{2 that} is consistent with gravity (Riω ² = g). If the laundry 6 attached to the inner circumferential surface of the washing-and-dehydrating drum 3 at the rotational speed N ₂ is uniform, this state can be maintained, but if there is an unbalanced portion, as shown in FIG. The laundry 6 above the suitable rotation radius Ri is attached to the inner circumferential surface of the washing and dehydrating drum 3 under the centrifugal force, but the laundry 6 in the unbalanced part has a smaller rotational radius Ra because of the smaller rotation radius Ra. Only the laundry 6 of the large, unbalanced portion falls under the influence of gravity near the upper side. The unbalanced laundry 6 is released by repeating the unbalanced laundry 6 rising to the top and falling during the rotation of the rotation speed N ₂ , and finally rotating radius Ri equal to gravity. The laundry 6 is attached to the inner circumferential surface of the washing and dehydrating drum 3, and the laundry 6 is uniform. A revolution number (N ₂₎ proceeds at a predetermined time (20s~30s), and then rotating the washing and dewatering drum (3), the number of revolutions predetermined dehydration (N _0). The rotation speeds (N ₁ , N ₂ ) are the centrifugal force (CF ₁ > 1G) at N ₁ and the centrifugal force (CF ₂ ≤1G) at N ₂ with respect to the gravity constant (G), and N ₁ > 80 rpm, N ₂ <80 rpm is preferable, for example, when the washing and dewatering drum 3 is 480 mm ψ and the laundry 6 is about 3 kg, the rotation speed N ₁ is about 100 rpm and the rotation speed N ₂ is about 72 rpm. .

According to the control method as described above, it is possible to reduce the unbalanced part of laundry (6) prior to administration to a predetermined dehydration rotation speed dehydration (N _0), it is possible to reduce the vibrations during the dewatering stroke.

② Rotational speed (N ₁ , N ₂ ) is determined by the amount of laundry; The amount of the laundry 6 is detected by, for example, the load torque at startup applied to the drive motor 5. According to the amount of the laundry 6, the size of the inner circumferential radius Ri of the laundry 6 in the abnormal state in which the laundry 6 is uniformly attached to the inner circumferential surface of the washing and dehydrating drum 3 is different. If the amount of (6) is large, the inner circumferential radius Ri of the laundry 6 is small. On the contrary, if the amount of the laundry 6 is small, the inner circumferential radius Ri of the laundry 6 becomes large. Therefore, detecting the amount of laundry (6) until dehydration and administration, thereby changing the rotational speed (N _1, N ₂₎ by the detection result. That is, when the laundry 6 is large, the rotational speeds N ₁ and N ₂ are increased as the inner circumferential radius of the laundry 6 is smaller so as to match gravity at the inner circumferential radial position of the laundry 6, and the laundry 6 is increased. On the contrary, the rotation speed (N ₁ , N ₂ ) can be made small.

As described above, according to the control method, the unbalance of the laundry 6 can be stably reduced by controlling the rotation speeds N ₁ and N ₂ in accordance with the amount of the laundry 6.

③ determine the rotation speed (N ₁ , N ₂ ) according to the quality of the cloth of the laundry; The quality of the cloth of the laundry 6 is detected by the variation of load torque, for example. Even when the weight of the laundry 6 is the same, the laundry 6 in the abnormal state in which the laundry 6 is uniformly attached to the inner circumferential surface of the washing and dehydrating drum 3 according to the quality of the cloth of the laundry 6. The inner circumferential radius Ri of the laundry 6 is smaller as the size of the inner circumferential radius Ri is different, and the quality of the cloth of the laundry 6 is smaller. ), The inner circumferential radius Ri becomes large. Therefore, the quality of the cloth of the laundry 6 is detected until before the dehydration stroke, and the rotation speeds N ₁ and N ₂ are changed by the detection result. That is, when the quality of the cloth of the laundry 6 is strong, the rotational speed N ₁ , N ₂ is increased by the smaller the inner circumference radius of the laundry 6 so that the inner circumferential radius position of the laundry 6 matches gravity. (6) When the quality of the fabric is soft, the rotation speed (N ₁ , N ₂ ) can be reduced.

As described above, according to the control method, the unbalance of the laundry 6 can be stably reduced by controlling the rotation speeds N ₁ and N ₂ in accordance with the quality of the cloth of the laundry 6.

(4) unbalance detection in the washing and dehydrating drum 3 by the load torque of the drive motor 5 at the rotational speed N ₂ ; The rotational speed of the drive motor 5 is detected by the rotation sensor, and the time-variation rate of the detected rotational speed is calculated by the calculation unit 11 to detect the load torque of the drive motor 5. In the time chart of FIG. 3, the driving is performed at rotation speeds N ₁ and N ₂ before the predetermined rotation speed N ₀ is reached. At the rotational speed N ₂ , when the unbalanced amount of the laundry 6 shown in FIG. 6A is large, the driving motor 5 when the unbalanced portion is rotated upwards and rotated downwardly. The load torque is different, and when it is rotated upward, the rotation of the washing and dehydrating drum 3 is slowed down, and when it is rotated downward, the washing and dehydration drum 3 is accelerated by the influence of inertia and gravity of the unbalanced part. The rotation unevenness in one rotation of the dehydrating drum 3 is large, and unlike the control method of 1) above, not only the laundry 6 in the unbalanced portion but also the laundry 6 other than the uniformly attached laundry 6 are shown in FIG. As shown by), it falls from the upper side. In the unbalanced state as shown in FIG. 6B and the unbalanced state as shown in FIG. 4B, the load torque of the drive motor 5 is different, so the variation rate of the rotational speed of the drive motor 5 is different. , The former becomes larger. Therefore, if the rate of change of the rotational speed of the drive motor 5 detected at the rotational speed N ₂ is equal to or greater than a predetermined value (unbalance detection), the rotational speed after rotating again at the rotational speed N ₁ without entering the dehydration stroke Rotate to (N ₂ ) to perform unbalance detection. Repeat the operation of the rotation speed (N ₁ , N ₂ ) until the unbalance disappears, and when the unbalance disappears, the process shifts to the dehydration stroke.

As described above, according to this control method, since the state of the laundry 6 varies greatly depending on the unbalanced amount of the laundry 6, it is possible to reliably detect a state where the unbalance amount is large.

(5) unbalance detection in the washing-and-dehydrating drum (3) by the difference in the load torque of each drive motor (5) at rotational speed (N ₁ ) and rotational speed (N ₂ ); The time varying rate at the rotational speed N ₁ and the rotational speed N ₂ is calculated by the calculation unit 11, and the result of the calculation is stored in the storage unit 12 to obtain the difference between them. The variation rate (δ ₁ ) of the rotational speed of the drive motor 5 at the rotational speed N ₁ is detected, and the variation rate δ ₂ of the rotational speed of the drive motor 5 at the next rotational speed N ₂ is determined. Detect. As described in the control method ④, δ ₂ becomes larger than δ ₁ if it is in an unbalanced state at the rotation speed N ₂ . For this reason, operation of both car in the operating section 11, the difference then rotated at a predetermined value or more (unbalanced detection) when dehydrated can administration is rotated does not enter again (N _1), rotational speed (N ₂₎ Rotate to to perform unbalance detection. Repeat the operation of the rotation speed (N ₁ , N ₂ ) until the unbalance disappears, and when the unbalance disappears, the process shifts to the dehydration stroke.

As described above, according to the control method, it is possible to reliably detect a large unbalanced amount of the laundry 6 even if there is no information on the amount of the laundry 6 and the quality of the cloth.

(6) detecting the change rate of the rotational speed of the drive motor 5 by the change rate of the load torque of the drive motor 5; The rotational speed of the drive motor 5 is detected by the rotation sensor, and the input voltage of the drive motor 5 is varied in the control circuit 10 so as to keep the rotational speed constant. Then, from the change in the input voltage of the two-drive motor 5, the calculation unit 11 calculates a time variation rate of the load torque of the drive motor 5 to detect the change rate of the rotation speed of the drive motor 5. Therefore, even if this method is used, unbalance detection in the washing-and-dehydrating drum 3 in the control method ④ or ⑤ is possible.

(7) The rotation speed (N ₁ → N ₂ → N ₁ → N ₂ ) is repeated until the predetermined unbalance is less than or equal. Even after this repetition, the rotation speed (N ₁ , N ₂ ) is increased and the predetermined dewatering rotation speed is reached. Lower (N ₀ ); It demonstrates using the flowchart of FIG. In the time chart of FIG. 3, the unbalance detection (control method ④ or ⑤) is performed at the time of rotation of the rotation speed N ₂ (step 102) after the rotation by the rotation speed N ₁ (step 101). performed (step 103). when the unbalanced amount of laundry (6) large detection again rotated after a predetermined time up to the (N _1), by rotating a rotational speed (N ₂₎ is subjected to an unbalanced detection (step (101) to (103). Even if the rotation speed N ₁ and the rotation speed N ₂ are repeated a predetermined number of times (step 104), when it is detected that the amount of unbalance of the laundry 6 is large, water is supplied once to solve the entanglement of the laundry 6. The washing and dehydrating drum (3) is subjected to several times of forward rotation, stop, half-turn, and stop at 50 rpm, and after draining (steps 105 to 109) again, the rotation speed (N ₁ ) and the rotation speed (N ₂ ) Carry out the rotation. After that, similarly, even after repeating a predetermined number of times, the rotation speed N ₁ and the rotation speed N ₂ , when the unbalance is large, the rotation speed N ₁ and the rotation speed N ₂ are raised to increase the gravity. In accordance with, the inner circumferential rotation radius of the laundry 6 is decreased, the allowable range of unbalance is increased, and the predetermined dehydration rotation speed N ₀ is lowered (step 110), and the rotation speeds N ₁ , N ₂ are The rotation process (steps 111 and 112) and the predetermined dehydration rotation speed N ₀ stroke (step 113) are performed to complete dehydration. When the unbalance amount is detected by the unbalance detection in step 103, the rotation speed is immediately changed to a predetermined dehydration rotation speed N ₀ stroke (step 114) without changing the rotation speed, thereby completing the dehydration.

As described above, according to this control method, the unbalance amount of the laundry 6 is detected, and when the unbalance amount is large, the process shifts to a smaller stroke to reduce the unbalance amount, and when the unbalance amount cannot be reduced, a predetermined dewatering rotation speed ( By lowering N ₀ ), dehydration can be completed without generating large vibration.

As described above, according to the invention as set forth in claim 1, the steps of rotating the laundry at a lower rotation speed than the predetermined rotation speed before reaching the predetermined rotation speed at the time of dehydration operation of the laundry in the washing-and-dewatering drum are plural steps. In addition, since at least one of the plurality of steps has a control means for controlling the rotation speed to be lower than the rotation speed of the previous step, the laundry is uniformly attached to the inner circumferential surface of the washing and dewatering drum before the dehydration stroke at the predetermined rotation speed. The unbalanced portion can be made small, and the vibration during the dewatering stroke can be made small.

According to the invention described in claim 2, the rotational speed of the preceding step is "N ₁ ", and the rotational speed of the step of decreasing the rotation speed is "N ₂ ", the inner peripheral surface of the washing and dehydrating drum at the rotational speed (N ₁ ) a centrifugal force in the mean inner radius of the attached laundry "CF _1", a centrifugal force in the mean inner radius of the laundry attached to the inner peripheral surface of the washing and dewatering drum when the rotational speed _{(N 2) "CF 2"} , gravity When the constant is set to “G”, CF ₁ 〉 1G and CF ₂ ≤ 1G, the laundry is uniformly attached to the inner circumferential surface of the washing and dehydrating drum, so that the unbalanced portion becomes small, so that vibration during dehydration administration can be surely reduced. have.

According to the invention described in claim 3, since the rotation speed N ₁ of the previous step and the rotation speed N ₂ of the step of decreasing the rotation speed are determined by the amount of the laundry, unbalanced laundry even if the amount of the laundry changes. Can be made small stably.

According to the invention as set forth in claim 4, since the rotation speed N ₁ of the previous step and the rotation speed N ₂ of the lowering step are determined according to the quality of the cloth of the laundry, even if the amount of the laundry is changed, the laundry is changed. The unbalance of can be made small stably.

According to the invention as set forth in claim 5, since the unbalance of the laundry in the washing-and-dehydrating drum is detected by the load torque of the motor driving the washing-and-dehydrating drum at the rotational speed N ₂ of the step of decreasing the rotational speed. In the unbalanced state and the small state, the load torque of the drive motor is different, so the unbalanced amount of laundry can be detected reliably.

According to the invention as set forth in claim 6, the difference between the load torque of the motor driving the washing and dewatering drum at each of the rotational speed N ₁ at the previous stage and the rotational speed N ₂ at the lowering speed Since the unbalance of the laundry in the washing-and-dehydrating drum is detected, the load torque side of the drive motor at the rotational speed (N ₂ ) at which the load of the laundry falls is increased when the unbalanced state is increased. It can be detected reliably.

According to the invention as set forth in claim 7, since the steps of the rotation speed N ₁ and the steps of the rotation speed N ₂ are repeated until a predetermined unbalance or less is achieved, the uniformity of the laundry during the dehydration stroke is improved and the vibration is low. Anger can be realized more.

According to the invention as set forth in claim 8, when the predetermined unbalance is not less than or equal to the rotational speed N ₁ and the rotational speed N ₂ , respectively, a predetermined amount is raised, and the predetermined dewatering rotational speed N ₀ is a predetermined amount. Since it is made low, the state which does not become below predetermined unbalance can be solved better, and dehydration can be completed without generating big vibration.

Claims (9)

At the time of dehydration operation of the laundry in the washing-and-dehydrating drum, there are a plurality of steps of rotating at a lower speed than the predetermined dewatering speed before reaching a predetermined dewatering speed, and at least one of the plurality of steps is more than the previous speed. A drum type washing machine having control means for controlling the rotation speed to have a step of decreasing. The method of claim 1, The rotational speed of the previous step is "N ₁ ", the rotational speed of the step of decreasing the rotation speed "N ₂ ", the average inner radius of the laundry attached to the inner peripheral surface of the washing and dehydration drum at the rotational speed (N ₁ ) When the centrifugal force of "CF ₁ ", the centrifugal force in the mean inner circumferential radius of the laundry attached to the inner circumferential surface of the washing and dehydrating drum at the rotational speed (N ₂ ) is "CF ₂ " and the gravity constant is "G". , CF ₁ 〉 1G and CF ₂ ≦ 1G. The method according to claim 1 or 2, Drum speed washing machine, characterized in that for determining the rotational speed (N ₁ ) of the previous step and the rotational speed (N ₂ ) of the step of decreasing the rotation speed by the amount of the laundry. The method according to claim 1 or 2, Drum speed washing machine, characterized in that for determining the rotational speed (N ₁ ) of the previous step and the rotational speed (N ₂ ) of the step of decreasing the rotation speed according to the quality of the cloth of the laundry. The method according to claim 1 or 2, The drum type washing machine detects the unbalance of the laundry in the washing-and-dewatering drum by the load torque of the motor that drives the washing-and-dehydrating drum at the rotational speed (N ₂ ) of the step of decreasing the rotational speed. The method according to claim 1 or 2, The washing-and-dehydrating drum according to the difference in the load torque of the motor that drives the washing-and-dehydrating drum at each of the rotational speed N ₁ at the previous stage and the rotational speed N ₂ at the lowering stage. The drum type washing machine which detects the unbalance of the laundry inside. The method of claim 5, Drum-type washing machine characterized in that the steps of the rotation speed (N ₁ ) and the step of the rotation speed (N ₂ ) is repeated until a predetermined unbalance or less. The method of claim 7, wherein During the dehydration operation of the laundry in the washing-and-dewatering drum, a step of rotating at a lower rotation speed than the predetermined dehydration rotation speed No before the predetermined dewatering rotation speed No has a plurality of steps, which is equal to or less than the predetermined unbalance. When it does not become the drum type washing machine, characterized in that the rotational speed (N ₁ ) and the rotational speed (N ₂ ) to raise a predetermined amount, respectively, and the predetermined dehydration rotational speed (N ₀ ) is lowered by a predetermined amount. The method of claim 6, Drum-type washing machine characterized in that the steps of the rotation speed (N ₁ ) and the step of the rotation speed (N ₂ ) is repeated until a predetermined unbalance or less.