US20120222222A1

US20120222222A1 - Method for controlling washing machine

Info

Publication number: US20120222222A1
Application number: US13/358,271
Authority: US
Inventors: Aekyung Chae; Youngjong KIM
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2011-03-03
Filing date: 2012-01-25
Publication date: 2012-09-06
Also published as: KR20120100321A; CN103403244A; WO2012118278A3; WO2012118278A2

Abstract

Disclosed is a method for controlling a washing machine capable of compensating for a vibration characteristic due to an unbalanced state of a drum, by effectively controlling a ball balancer for compensating for a balance of a rotary body such as a drum. The method includes accelerating the drum having laundry therein for a first time duration (t1) until the drum reaches a reference speed from a stationary state, and decelerating the drum for a second time duration (t2) longer than the first time duration (t1) until the drum reaches the stationary state from the state having the reference speed.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 10-2011-0019131, filed on Mar. 3, 2011, which is hereby incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a washing machine, and particularly, to a method for controlling a washing machine capable of compensating for a vibration characteristic due to an unbalanced state of a drum, by effectively controlling a ball balancer for compensating for a balance of a rotary body such as a drum.
2. Background of the Invention
Generally, a washing machine serves to accelerate a chemical operation of a detergent by forcibly forming a current of washing water inside a drum with using a mechanical force, and serves to enhance a washing effect by applying a physical operation such as frictions or impacts to laundry.
FIG. 1 is a view showing a top load type of washing machine in accordance with the conventional art, in which laundry is put through an upper part of the washing machine under a configuration that a shaft is vertically disposed.
Referring to FIG. 1, the washing machine 10 comprises a cabinet 8 which forms the appearance, a reservoir (or tub) 1 disposed in the cabinet 8, and a drum 2 rotatably disposed in the reservoir 1. The drum is provided with a rotatable pulsator 3 at a lower part thereof, and the drum and the pulsator 3 are driven by being connected to a shaft 5 disposed in a vertical direction and connected to a driving motor 7.
Generally, the washing machine has a washing process and a dehydrating process. In case of the washing process, the pulsator 3, or the pulator 3 and the drum 2 are rotated to rotate laundry and water. In case of the dehydrating process, water is discharged and the drum 2 is rotated with a high speed, thereby removing water from laundry by a centrifugal force.
During the washing process or the dehydrating process, an unbalance occurs due to movements of the drum and a concentrated state of laundry. This may result in noises and vibrations. In order to prevent the noises and vibrations, the reservoir 1 is suspended at a cabinet by a suspension load 4. And, a ball balancer 9 is provided at an upper part of the drum 2 in a circumferential direction.
The ball balancer 9 serves to compensate for an unbalance of the drum due to a concentrated state of laundry inside the drum. Referring to FIG. 2, the ball balancer 9 is configured as a ring-shaped racer 9 c having therein a plurality of metallic balls 9 c. And, fluid 9 b such as oil is filled in the racer 9 a.
When the drum rotates in an unbalanced state due to a concentrated state of laundry contained in the drum, the ball balancer 9 moves in a direction for compensating for the unbalance by a difference of a centrifugal force. As a result, the ball balancer 9 makes the drum recover a balanced state.
In case of a dehydrating process, only wet laundry remains in the drum. This may cause the drum to be in a concentrated state. In order to prevent the concentrated state of the drum at an early dehydrating process, the balls have to be uniformly distributed in the ball balancer so that the ball balancer can allow the drum to rapidly recover a balanced state.
However, balls provided in a general ball balancer are not rapidly distributed since fluid is filled in the ball balancer. In this case, if the balls are concentrated to one side and laundry is concentrated to the same direction or a neighboring direction during a washing process, an unbalance of the drum becomes severe at an early dehydrating process. This may increase vibrations. Furthermore, this may cause the reservoir (tub) to collide with the cabinet due to the unbalanced state of the drum.

SUMMARY OF THE INVENTION

Therefore, an aspect of the detailed description is to provide a method for controlling a washing machine capable of allowing a drum to maintain a balanced state, by uniformly distributing balls disposed in a ball balancer, before the drum starts to rotate during a dehydrating process, etc. when an unbalance may occur.
Another aspect of the detailed description is to provide a method for controlling a washing machine capable of reducing vibrations of a drum and preventing a reservoir from colliding with a cabinet, by allowing a drum to maintain a balanced state by controlling a ball balancer.
To achieve these and other advantages and in accordance with the purpose of this specification, as embodied and broadly described herein, there is provided a method for controlling a washing machine having a drum where a ball balancer is installed, the method comprising: accelerating the drum having laundry therein for a first time duration (t1) until the drum reaches a reference speed from a stationary state; and decelerating the drum for a second time duration (t2) longer than the first time duration (t1) until the drum reaches the stationary state from the state having the reference speed.
Here, the second time duration (t2) may be longer than the first time duration (t1) by at least two times.
The first time duration may be 5 seconds, and the second time duration may be 10 seconds or more. The reference speed may be 80 rpm.
Preferably, the acceleration and the deceleration of the drum may be performed a plurality of times in a repeated manner. The acceleration and the deceleration of the drum may be repeated with a constant period. After the acceleration and decoration of the drum, a predetermined standstill state may be implemented.
As the acceleration of the drum is high, a speed difference between laundry and the ball balancer may increase. This may allow the balls to move in a is direction for compensating for an unbalanced state of the drum. Accordingly, the drum may be rapidly accelerated and then slowly decelerated for uniform distributions of the balls.
Preferably, a dehydrating process may be started after the acceleration and the deceleration of the drum. This may allow the balls inside the ball balancer to be uniformly distributed by the acceleration and the deceleration of the drum, before a dehydrating process of the washing machine is started.
As the balls are made to be uniformly distributed in the ball balancer before a dehydrating process when an unbalance may easily occur, excessive vibrations may be prevented.
According to another aspect of the present invention, there is provided a method for controlling a washing machine having a drum where a ball balancer is installed, the method comprising: a washing process for performing a washing operation by supplying washing water into the drum, and by stirring laundry; and a dehydrating process for discharging the washing water contained in the drum, and separating the washing water contained in the laundry from the laundry, wherein the dehydrating process comprises a discharging step of discharging the washing water contained in the drum, a balancing step of compensating for a balance of the drum, and a dehydrating step of separating the washing water from the laundry inside the drum by rotating the drum with a high speed, wherein in the balancing step, the balls disposed in the ball balancer are made to be uniformly distributed by acceleration and deceleration of the drum before the dehydrating step.
In the balancing step, the drum having the laundry therein may be accelerate for a first time duration (t1) until the drum reaches a reference speed from a stationary state, and then the drum may be decelerated for a second time duration (t2) longer than the first time duration (t1) until the drum reaches the stationary state from the state having the reference speed.
In the balancing step, the acceleration and the deceleration of the drum may be performed with a constant period. The acceleration and the deceleration of the drum may be repeated a plurality of times. After the acceleration and decoration of the drum, a predetermined standstill state may be implemented.
In the present disclosure, the balls may be made to be uniformly distributed in the ball balancer before a dehydrating process when an unbalance may easily occur. This may allow the drum to maintain a balanced state.
Furthermore, in the present disclosure, the ball balancer may be efficiently controlled to allow the drum to maintain a balanced state. This may reduce vibrations of the drum, and prevent the reservoir from colliding with the cabinet.
Further scope of applicability of the present application will become more apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from the detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments and together with the description serve to explain the principles of the invention.

In the drawings:

FIG. 1 is a schematic view of a washing machine in accordance with the conventional art;

FIG. 2 is a schematic view of a ball balancer of the washing machine of FIG. 1;

FIGS. 3 and 4 are graphs each showing a change of a rotation speed of a drum according to a first embodiment of the present disclosure; and

FIGS. 5 and 6 are schematic views showing a relative position of balls disposed in a ball balancer with respect to laundry according to a first embodiment of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

Description will now be given in detail of the exemplary embodiments, with reference to the accompanying drawings. For the sake of brief description with reference to the drawings, the same or equivalent components will be provided with the same reference numbers, and description thereof will not be repeated.
In a method for controlling a washing machine having a drum where a ball balancer is installed according to a first embodiment of the present disclosure, the drum having laundry therein is accelerated for a first time duration (t1) until the drum reaches a reference speed from a stationary state. The, the drum is decelerated for a second time duration (t2) longer than the first time duration (t1) until the drum reaches the stationary state from the state having the reference speed.
The method is applied to a washing machine having a ball balancer in a drum. The washing machine having a ball balancer in a drum is already well-known, and thus its detailed explanations will be omitted.
The washing machine is provided with a controller (not shown). The controller is configured to determine a rotation speed of the drum, by controlling a driving motor which rotates the drum.
The drum is accelerated and decelerated in an alternating manner. More concretely, the drum having laundry therein is firstly accelerated for a first time duration (t1) until it reaches a reference speed from a stationary state. Then, the drum is decelerated for a second time duration (t2) longer than the first time duration (t1) until the drum reaches the stationary state from the state having the reference speed.
As the acceleration of the drum is high, a speed difference between laundry and the ball balancer may increase. This may allow the balls to move in a direction for compensating for an unbalanced state of the drum. As the drum is rapidly accelerated and then slowly decelerated, the balls are uniformly distributed in the ball balancer.
The first time duration (t1) and the second time duration (t2) may be set in various manners. For instance, the second time duration (t2) may be longer than the first time duration (t1) by at least two times. The first time duration may be 5 seconds, and the second time duration may be 10 seconds or more. Under these configurations, the balls may be uniformly distributed in the ball balancer by allowing the acceleration to be performed more rapidly than the deceleration.
The reference speed (ω0) may be also set in various manners. As aforementioned, as a speed difference between laundry and the ball balancer increases, the balls move in a direction for compensating for an unbalanced state of the drum. Accordingly, it is preferable to increase the reference speed for a large speed difference.
The driving motor for rotating the drum has to have a limited capacity. For instance, the reference speed may be 80 rpm. The capacity is limited with consideration of a performance of the driving motor of a general washing machine.
The acceleration and the deceleration of the drum may be repeatedly performed a plurality of times. As shown in FIG. 3, the acceleration and the deceleration of the drum may be periodically performed. The balls inside the ball balancer move in fluid. Accordingly, the repeated accelerations and decelerations may allow the balls to be re-aligned, thereby enhancing a balance of the drum.
After the acceleration and the deceleration of the drum, a standstill time duration (t3) may be implemented, which is shown in FIG. 4. Due to the standstill time duration (t3), an excessive load may be prevented from being applied to the driving motor of the drum, and the balls may move in the fluid filled in the ball balancer for a sufficient time. This may allow a position of the balls to be efficiently controlled.
FIGS. 5 and 6 show that positions of the balls inside the ball balancer are re-aligned by controlling the drum of the washing machine.
FIG. 5 shows a state prior to a dehydrating process, in which the balls 35 of the ball balancer 30 are positioned at the same side as laundry 40. As the drum of the washing machine is accelerated and decelerated, the position of the balls 35 inside the ball balancer is re-aligned during a dehydrating process as shown in FIG. 5. This may allow compensation for an unbalance of the drum.
FIG. 6 shows a state prior to a dehydrating process, in which the balls 35 of the ball balancer 30 are positioned in a direction facing the laundry 40, i.e., a direction for compensating for an unbalance of the drum. As the drum of the washing machine is accelerated and decelerated, the position of the balls 35 inside the ball balancer is nearly maintained as shown in FIG. 6 during the dehydrating process.
By the operations of the drum and the ball balancer, the position of the balls inside the ball balancer is re-aligned before a dehydrating process when an unbalance of the drum may easily occur due to rotations of the drum. This may allow the drum to maintain a balanced state.
In the preferred embodiment, it is preferable to start a dehydrating process after accelerating and decelerating the drum. The reason is because it is efficient to perform the acceleration and the deceleration before the rotary operation of the drum when an unbalance of the drum may easily occur due to a concentrated state of the laundry.
More concretely, the washing machine has a washing process and a dehydrating process. In case of the washing process, washing water is supplied into the drum and the laundry is stirred. And, in case of the dehydrating process, the water washing inside the drum is discharged, and the washing water contained in the laundry is separated from the laundry.
The dehydrating process includes a discharging step of discharging the to washing water inside the drum, a balancing step of compensating for a balance of the drum, and a dehydrating step of separating the washing water from the laundry inside the drum by rotating the drum with a high speed.
In the balancing step, the balls disposed in the ball balancer are made to be uniformly distributed by acceleration and deceleration of the drum before the dehydrating step. More concretely, in the balancing step, the drum having the laundry therein is accelerated for a first time duration (t1) until the drum reaches a reference speed from a stationary state. Then, the drum is decelerated for a second time duration (t2) longer than the first time duration (t1) until the drum reaches the stationary state from the state having the reference speed.
The acceleration and the deceleration of the drum are repeated with a constant period. The acceleration and the deceleration of the drum are performed a plurality of times in a repeated manner. After the acceleration and decoration of the drum, a predetermined standstill state may be implemented. This was aforementioned, and thus detailed explanations thereof will be omitted.
Before the dehydrating process, the balls inside the ball balancer are uniformly distributed by the acceleration and the deceleration of the drum. This may allow the drum to maintain a balanced state.
Furthermore, the balls inside the ball balancer are uniformly distributed before the dehydrating process when an unbalance of the drum may easily occur. This may prevent excessive vibrations from occurring from the drum and the reservoir (tub).
The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present disclosure. The present teachings can be readily applied to other types of apparatuses. This description is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to obtain additional and/or alternative exemplary embodiments.
As the present features may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.

Claims

1. A method for controlling a washing machine having a drum where a ball balancer is installed, the method comprising:

accelerating the drum having laundry therein for a first time duration (t1) until the drum reaches a reference speed from a stationary state; and

decelerating the drum for a second time duration (t2) longer than the first time duration (t1) until the drum reaches the stationary state from the state having the reference speed.

2. The method of claim 1, wherein the second time duration (t2) is longer than the first time duration (t1) by at least two times.

3. The method of claim 2, wherein the first time duration is 5 seconds, and is the second time duration is 10 seconds or more.

4. The method of claim 3, wherein the reference speed is 80 rpm.

5. The method of claim 1, wherein the acceleration and the deceleration of the drum are performed a plurality of times in a repeated manner.

6. The method of claim 5, wherein the acceleration and the deceleration of the drum are repeated with a constant period.

7. The method of claim 5, wherein after the acceleration and deceleration of the drum, a predetermined standstill state is implemented.

8. The method of claim 1, wherein a dehydrating process is started after the acceleration and the deceleration of the drum.

9. A method for controlling a washing machine having a drum where a ball balancer is installed, wherein balls mounted in the ball balancer are uniformly distributed by acceleration and deceleration of the drum before a dehydrating process of the washing machine.

10. A method for controlling a washing machine having a drum where a ball balancer is installed, the method comprising:

a washing process for performing a washing operation by supplying washing water into the drum, and by stirring laundry; and

is a dehydrating process for discharging the washing water contained in the drum, and separating the washing water contained in the laundry from the laundry,

wherein the dehydrating process comprises:

a discharging step of discharging the washing water contained in the drum;

a balancing step of compensating for a balance of the drum; and

a dehydrating step of separating the washing water from the laundry inside the drum by rotating the drum with a high speed, and

wherein in the balancing step, the balls disposed in the ball balancer are made to be uniformly distributed by acceleration and deceleration of the drum before the dehydrating step.

11. The method of claim 10, wherein in the balancing step, the drum having the laundry therein is accelerate for a first time duration (t1) until the drum reaches a reference speed from a stationary state, and then the drum is decelerated for a second time duration (t2) longer than the first time duration (t1) until the drum reaches the stationary state from the state having the reference speed.

12. The method of claim 11, wherein in the balancing step, the acceleration and the deceleration of the drum are repeated a plurality of times.

13. The method of claim 12, wherein the acceleration and the deceleration of the drum are repeated with a constant period.