KR101309295B1 - Drum Washing machine - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum type washing machine, and more particularly, to a drum type washing machine capable of reducing the unbalance amount and reducing the overall washing time by varying the number of revolutions for detection in accordance with the amount of laundry. The drum washing machine of the present invention comprises a rotary tub; A motor for rotating the rotary tub; A weight sensing part for sensing a weight of laundry laid on the rotary tub; A controller for controlling the motor by varying the target speed according to the weight of the laundry in a winder stroke to increase the speed of the rotating tub to a target speed so as to uniformly distribute the laundry in the spinning tub in a dewatering cycle; . The drum washing machine of the present invention has the effect of reducing the overall washing time.

Description

[0001] DRUM WASHING MACHINE [0002]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a state according to the amount of laundry in a rotary tub. FIG.

Fig. 2 is a view showing a state of laundry and a force acting on the laundry in the drum when decelerating. Fig.

3 is a graph showing the speed of a rotary tub during a dewatering stroke according to the present invention.

4 is a schematic block diagram of a drum washing machine according to the present invention.

5 is a flow chart showing an example of a control process in the dehydration stroke according to the present invention.

Description of the Related Art [0002]

100: Rotating tub 110: Laundry

400: weight detecting section 410:

420: Imbalance detection unit 430: Motor drive unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum type washing machine, and more particularly, to a drum type washing machine capable of reducing the unbalance amount and reducing the overall washing time by varying the number of revolutions for detection in accordance with the amount of laundry.

Generally, a drum type washing machine comprises a cylindrical drum provided inside a main body of a washing machine, and a motor for rotating the rotary tub and the rotary tub inside the drum. It is advantageous in that the washing ability is superior to that of a general washing machine, the damage of the cloth is lessened in washing, and the use of less water is advantageous.

The drum washing machine tends to be distributed so that the laundry is tilted downward under the influence of gravity because the rotary drum of the drum rotates in a state in which the rotary shaft of the drum is laid horizontally. Therefore, unbalance is generated better than a pearl shaper type washing machine, and such unbalance causes vibration in rotation for dewatering. In addition, such unbalance has a problem in that mechanical damage is caused in the resonance band due to various mechanical factors in the process of increasing the number of revolutions at a high speed in the dewatering stroke.

In the drum type washing machine, it is necessary to arrange the laundry evenly before the dewatering cycle, that is, the winder stroke. Such a winder stroke can be performed while increasing the number of rotations to a certain number of revolutions and reducing the number of revolutions.

A conventional dehydration process of the drum washing machine is disclosed in Korean Patent Laid-Open Publication No. 1996-23426. This publication discloses a preliminary dewatering step of dewatering at a low speed at a constant speed and a method of detecting laundry imbalance and repelling the laundry by repeating the driving and stopping at a constant speed and proceeding the dewatering process through the acceleration section if unbalance is not detected .

In the disclosed conventional dehydration process, there is no step of detecting the weight of the laundry, so that the dehydration process is performed irrespective of the weight of the laundry. However, depending on the weight of the laundry, the radius of the laundry varies, which causes a difference in centrifugal force at the same number of revolutions. Therefore, the number of revolutions in which laundry is dropped and rearranged in the take-up machine is different from each other. Conventionally, when the weight of the laundry is larger or smaller than the predetermined number of revolutions, the dehydration process is performed at a constant number of revolutions. Therefore, it takes a long time to reduce the unbalance of the laundry, thereby increasing the time required for entering into the high-speed dehydration.

In addition, since the laundry may flow even after the unbalance is detected, the unbalance may be erroneously detected.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a washing tub which is capable of accurately detecting unbalance and minimizing a time required for dehydration by appropriately setting the speed of the rotary tub in accordance with the weight of the laundry in the reduction and detection of unbalance And a drum washing machine.

According to an aspect of the present invention, there is provided a drum washing machine comprising: a rotary tub; A motor for rotating the rotary tub; A weight sensing part for sensing a weight of laundry laid on the rotary tub; A controller for controlling the motor by varying the target speed according to the weight of the laundry in a winder stroke to increase the speed of the rotating tub to a target speed so as to uniformly distribute the laundry in the spinning tub in a dewatering cycle; .

The controller may further include a controller for controlling the rotation speed of the rotating tub to decrease the speed of the rotating tub at a predetermined reduction rate to reduce the unbalanced state of the laundry after maintaining the target speed for a predetermined time when the laundry reaches the predetermined target speed, Thereby controlling the motor.

Also, the motor is a BLDC motor, and the controller controls the unbalance of the rotary tub by using the variation width of the q-axis current corresponding to the rotation torque among the currents applied to the BLDC motor in the speed deceleration period. Or not.

Further, the controller may control the rotation speed of the BLDC motor to increase the speed of the BLDC motor to perform high-speed dehydration when it is determined that the rotary tub is not in an unbalanced state.

The control unit controls the motor to increase the target speed as the weight of the laundry increases.

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

)이 작아지게 된다. 이렇게 동일 회전수에서 원심력이 다르기 때문에 세탁물에 작용하는 중력과 원심력이 같아지는 임계 rpm도 다르게 된다. FIG. 1 shows that the radius from the center varies depending on the amount of the laundry 110 that is input into the rotary tub 100. As the radius from the center decreases, the centrifugal force at the same number of revolutions (

) Becomes smaller. Since the centrifugal force is different at the same number of revolutions, the critical rpm at which the centrifugal force and the gravitational force acting on the laundry are equal becomes different.

The winder stroke rearranges the laundry by using the flow of the laundry generated in relation to the gravity with a change in the centrifugal force which varies with the rotation, while increasing or decreasing the speed of the rotary tub to a proper number of revolutions.

Referring to FIG. 2, when the winder is operated while increasing the number of revolutions, the laundry having the largest radius (R1) has the lowest critical rpm because the centrifugal force is largest at the same number of revolutions. As the number of revolutions increases, the washing tubs are brought into close contact with the rotating tub in order to uniformly rearrange laundry. In addition, the radius of laundry to the outermost laundry varies depending on the weight of the laundry. That is, when the weight of the laundry is small, the outermost laundry also has a critical rpm at a low rotation speed.

Therefore, when the weight of the laundry is small, laundry can be relocated even at a low rotation speed. Therefore, if the number of revolutions for detecting and reducing unbalance is set high, it takes a long time to satisfy the reference value of unbalance. Further, when the weight of the laundry is large, if the laundry is unbalanced at a low rotational speed, laundry may flow after the laundry is sensed, thereby causing vibration and noise in the dehydrating process.

4 is a schematic block diagram of a drum washing machine according to the present invention. The drum washing machine according to the present invention includes a weight sensing part 400 for sensing the weight of the laundry, an unbalance sensing part 420 for detecting unbalance of the laundry, i.e., unbalance of the laundry, and a motor driving part 430 And a control unit 410 for controlling the motor driving unit 430 according to the detection results of the weight detecting unit 400 and the unbalance detecting unit 420.

3 and 5, when the laundry is charged into the rotary tub 100 of the drum type washing machine, the speed of the motor detected while rotating the motor at a predetermined RPM is used The weight of the laundry is sensed by the weight sensing unit 400 in step S510. In step S520, the weight of the laundry is compared with predetermined reference weights. In step S520, But it can be divided into two steps or more. As mentioned above, since the target rotation speed for each weight step has a lower critical rpm as the weight of the laundry is smaller, the target rotation speed is set to be smaller. Even if the target rotation speed is set to such a small value, the unbalance can be sufficiently reduced and detected, and the unbalance can be reduced and detected at a low rotation speed, thereby reducing the overall dewatering time.

If the weight of the laundry is large, the target rotation speed is set to be high so that accurate unbalance can be detected. (S531, S532, S533) When the target rotation speed is set, the speed of the rotary tub is increased to the target rotation speed, (Step (S540), step S550). If the target rotation speed is reached, the controller detects the unbalance (2) (step S560). After a certain period of time, the motor is kept at the minimum rotation speed for detecting and reducing unbalance. Slowly decelerate the speed with a smaller slope. The laundry is uniformly relocated through the deceleration (step (3)) (step S570). Whether or not the rotation speed of the lowest limit has been reached is determined by detecting the number of rotations of the motor. If not, the controller determines whether the unbalance amount is smaller than a preset reference value . The determination of the unbalance amount is made by converting the three-phase current applied to the BLDC motor used in the drum washing machine into the two-phase current and using the fluctuation width of the q-axis current related to the torque of the motor among the converted two- (4) (S580, S590, S600). If the laundry is unbalanced to the lowest rotation speed, it is determined that the drum washing machine is in the unbalanced state. If the fluctuation width is smaller than the predetermined reference value, (Step S610) to stop the drum or to rotate the rotary tub in normal and reverse directions to prevent damage.

As described above in detail, according to the present invention, the time required for washing can be minimized by varying the number of revolutions for reducing and detecting the unbalance amount according to the weight of the laundry.

In addition, since the unbalance amount is detected by an appropriate number of revolutions according to the weight of the laundry, unbalance of the laundry can be accurately detected.

Claims (12)

A dewatering control method of a drum washing machine comprising a rotary tub for receiving laundry and a motor for rotating the rotary tub, Detecting the weight of the laundry; Determining whether the weight of the detected laundry belongs to one of the weight stages of the laundry divided into at least two stages, and setting a target rotation speed of the motor according to the determined weight stage of the laundry; And performing a winder to uniformly relocate the laundry in the rotary tub while increasing the speed of the motor to the target rotation speed. The method according to claim 1, Detecting an unbalance amount of the laundry while reducing the speed of the motor when the speed of the motor reaches the target rotation speed; And controlling the speed of the motor to substantially dewater the laundry in accordance with an unbalance amount of the laundry. The method of claim 1, wherein setting the target rotational speed of the motor comprises: Wherein the target rotational speed of the motor is set so that the target rotational speed of the motor is proportional to the weight of the laundry. The method according to claim 1, Further comprising maintaining the speed of the motor at the target number of revolutions for a predetermined time before decreasing the speed of the motor after the speed of the motor reaches the target number of revolutions. 3. The method of claim 2, And if the detected amount of unbalance of the laundry is smaller than a preset reference value, the speed of the motor is increased to perform high-speed dehydration. 6. The method of claim 5, When the detected amount of unbalance of the laundry is equal to or greater than the preset reference value when the speed of the motor reaches the preset lowest speed while the speed of the motor is reduced while detecting the unbalance amount of the laundry, Is stopped. A rotary tub; A motor for rotating the rotary tub; A weight sensing unit for sensing a weight of laundry laid on the rotary tub; And Determining whether the weight of the laundry belongs to one of the weight stages of the laundry divided into at least two stages, setting the target rotation speed of the motor according to the determined weight stage of the laundry, And a controller for increasing the speed of the motor to the target rotation speed so as to uniformly relocate the motor in the drum. 8. The method of claim 7, Wherein the control unit detects an unbalance amount of the laundry while reducing the speed of the motor when the speed of the motor reaches the target rotation speed and detects an unbalance amount of the laundry when the speed of the motor reaches the target rotation speed, Drum washing machine to control the speed. 8. The method of claim 7, Wherein the control unit sets the target rotation speed of the motor so that the target rotation speed of the motor is proportional to the weight of the laundry. 8. The method of claim 7, Wherein the control unit maintains the speed of the motor at the target rotation speed for a predetermined time before decreasing the speed of the motor after the speed of the motor reaches the target rotation speed. 8. The method of claim 7, Wherein the motor is a BLDC motor and the control unit controls the amount of unbalance of the laundry by using the fluctuation range of the q-axis current corresponding to the rotational torque among the currents applied to the non- Detecting drum washing machine. 9. The method of claim 8, Wherein the control unit increases the speed of the motor to perform high-speed dehydration if the unbalance amount of the laundry is smaller than a preset reference value.

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