U.S. patent application number 11/036017 was filed with the patent office on 2005-11-17 for method for controlling dehydration of washing machine.
This patent application is currently assigned to LG Electronics Inc.. Invention is credited to Choi, Byung Keol, Jeon, Si Moon, Lee, Tae Hee, Seo, Hyun Seok.
Application Number | 20050251926 11/036017 |
Document ID | / |
Family ID | 35307944 |
Filed Date | 2005-11-17 |
United States Patent
Application |
20050251926 |
Kind Code |
A1 |
Lee, Tae Hee ; et
al. |
November 17, 2005 |
Method for controlling dehydration of washing machine
Abstract
A method for controlling dehydration of a washing machine, in
which one reference degree of eccentricity in the direction, in
which the vibration of a tub is large, is set to be lower than the
other reference degree of eccentricity in the direction, in which
the vibration of the tub is small, or one reference degree of
eccentricity in the direction to the installation of a drying
device is set to be lower than the other reference degree of
eccentricity in the reverse direction, thereby preventing the
washing machine from being excessively vibrated and allowing the
washing machine to easily perform a dehydrating operation.
Inventors: |
Lee, Tae Hee; (Buchun-si,
KR) ; Jeon, Si Moon; (Seoul, KR) ; Seo, Hyun
Seok; (Inchun-si, KR) ; Choi, Byung Keol;
(Inchun-si, KR) |
Correspondence
Address: |
GREENBLUM & BERNSTEIN, P.L.C.
1950 ROLAND CLARKE PLACE
RESTON
VA
20191
US
|
Assignee: |
LG Electronics Inc.
Seoul
KR
|
Family ID: |
35307944 |
Appl. No.: |
11/036017 |
Filed: |
January 18, 2005 |
Current U.S.
Class: |
8/158 ;
8/159 |
Current CPC
Class: |
D06F 2103/26 20200201;
D06F 37/203 20130101; D06F 33/48 20200201 |
Class at
Publication: |
008/158 ;
008/159 |
International
Class: |
D06F 033/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 12, 2004 |
KR |
2004-33594 |
Claims
What is claimed is:
1. A method for controlling dehydration of a washing machine, in
which reference degrees of eccentricity in the clockwise and
counterclockwise direction of a drum, for determining whether or
not main dehydration is performed, are set to different values.
2. The method as set forth in claim 1, wherein the reference degree
of eccentricity in the direction, in which the vibration of a tub
is large, is set to be lower than the reference degree of
eccentricity in the direction, in which the vibration of the tub is
small.
3. The method as set forth in claim 1, wherein, in case that a
drying device is eccentrically installed at left or right side from
the center of a tub, one reference degree of eccentricity in the
direction of installation of the drying device is set to be lower
than the other reference degree of eccentricity in the reverse
direction.
4. The method as set forth in claim 1, wherein, in case that the
numbers of dampers connected to left and right sides of a tub
differ from each other, one reference degree of eccentricity in the
direction to the dampers having a small number is set to be lower
than the other reference degree of eccentricity in the reverse
direction.
5. The method as set forth in claim 1, wherein, in case that the
numbers of springs connected to left and right sides of a tub
differ from each other, one reference degree of eccentricity in the
direction to the springs having a small number is set to be lower
than the other reference degree of eccentricity in the reverse
direction.
6. A method for controlling dehydration of a washing machine,
comprising the steps of: (i) rotating a drum in one direction out
of the clockwise and counterclockwise directions, and sensing a
degree of eccentricity; (ii) stopping the rotation of the drum when
the degree of eccentricity sensed in step (i) is not lower than a
first reference degree of eccentricity, and performing main
dehydration when the degree of eccentricity sensed in step (i) is
lower than the first reference degree of eccentricity; (iii)
rotating the drum in the direction reverse to the rotation in step
(i) when the rotation of the drum is stopped in step (ii), and
sensing a degree of eccentricity; and (iv) stopping the rotation of
the drum when the degree of eccentricity sensed in step (iii) is
not lower than a second reference degree of eccentricity set to a
value differing from that of the first reference degree of
eccentricity, and performing main dehydration when the degree of
eccentricity sensed in step (iii) is lower than the second
reference degree of eccentricity, wherein all steps from step (i)
are repeated in case that the rotation of the drum is stopped in
step (iv).
7. The method as set forth in claim 6, wherein, in the sense of the
degree of eccentricity, a motor for rotating the drum is
accelerated such that the rotational frequency (rpm) of the motor
reaches a predetermined rotational frequency (rpm), the motor is
maintained at a constant rotational speed for a predetermined time
when the rotational frequency (rpm) of the motor reaches the
predetermined rotational frequency (rpm), and then the motor is
turned off; and the degree of eccentricity is sensed using a
variation of the rotational speed (rpm) during a time of
maintaining the motor at the constant speed.
8. The method as set forth in claim 6, wherein one reference degree
of eccentricity, out of the first and second reference degrees of
eccentricity, in the direction, in which the vibration of a tub is
large, is set to be lower than the other reference degree of
eccentricity in the direction, in which the vibration of the tub is
small.
9. The method as set forth in claim 6, wherein, in case that a
drying device is eccentrically installed at left or right side from
the center of a tub, one reference degree of eccentricity, out of
the first and second reference degrees of eccentricity, in the
direction of installation of the drying device is set to be lower
than the other reference degree of eccentricity in the reverse
direction.
10. The method as set forth in claim 6, wherein, in case that the
numbers of dampers connected to left and right sides of a tub
differ from each other, one reference degree of eccentricity, out
of the first and second reference degrees of eccentricity, in the
direction to the dampers having a small number is set to be lower
than the other reference degree of eccentricity in the reverse
direction.
11. The method as set forth in claim 6, wherein, in case that the
numbers of springs connected to left and right sides of a tub
differ from each other, one reference degree of eccentricity, out
of the first and second reference degrees of eccentricity, in the
direction to the springs having a small number is set to be lower
than the other reference degree of eccentricity.
12. A method for controlling dehydration of a washing machine,
comprising the steps of: (i) rotating a drum in one direction out
of the clockwise and counterclockwise directions, and sensing a
degree of eccentricity; (ii) stopping the rotation of the drum and
performing disentanglement of laundry when the degree of
eccentricity sensed in step (i) is not lower than a first reference
degree of eccentricity, and performing main dehydration when the
degree of eccentricity sensed in step (i) is lower than the first
reference degree of eccentricity; (iii) rotating the drum in the
direction reverse to the rotation in step (i) when the rotation of
the drum is stopped and the disentanglement of laundry is performed
in step (ii), and sensing a degree of eccentricity; and (iv)
stopping the rotation of the drum and performing disentanglement of
laundry when the degree of eccentricity sensed in step (iii) is not
lower than a second reference degree of eccentricity set to a value
differing from that of the first reference degree of eccentricity,
and performing main dehydration when the degree of eccentricity
sensed in step (iii) is lower than the second reference degree of
eccentricity, wherein all steps from step (i) are repeated in case
that the rotation of the drum is stopped and the disentanglement of
laundry is performed in step (iv).
13. The method as set forth in claim 12, wherein, in the sense of
the degree of eccentricity, a motor for rotating the drum is
accelerated such that the rotational frequency (rpm) of the motor
reaches a predetermined rotational frequency (rpm), the motor is
maintained at a constant rotational speed for a predetermined time
when the rotational frequency (rpm) of the motor reaches the
predetermined rotational frequency (rpm), and then the motor is
turned off; and the degree of eccentricity is sensed using a
variation of the rotational speed (rpm) during a time of
maintaining the motor at the constant speed.
14. The method as set forth in claim 12, wherein one reference
degree of eccentricity, out of the first and second reference
degrees of eccentricity, in the direction, in which the vibration
of a tub is large, is set to be lower than the other reference
degree of eccentricity in the direction, in which the vibration of
the tub is small.
15. The method as set forth in claim 12, wherein, in case that a
drying device is eccentrically installed at left or right side from
the center of a tub, one reference degree of eccentricity, out of
the first and second reference degrees of eccentricity, in the
direction of installation of the drying device is set to be lower
than the other reference degree of eccentricity in the reverse
direction.
16. The method as set forth in claim 12, wherein, in case that left
and right suspension systems of the tub are bilaterally asymmetric,
one reference degree of eccentricity, out of the first and second
reference degrees of eccentricity, in the direction to the
suspension system having relatively large vibration is set to be
lower than the other reference degree of eccentricity in the
reverse direction.
17. The method as set forth in claim 12, wherein, in case that the
numbers of dampers connected to left and right sides of a tub
differ from each other, one reference degree of eccentricity, out
of the first and second reference degrees of eccentricity, in the
direction to the dampers having a small number is set to be lower
than the other reference degree of eccentricity in the reverse
direction.
18. The method as set forth in claim 12, wherein, in case that the
numbers of springs connected to left and right sides of a tub
differ from each other, one reference degree of eccentricity, out
of the first and second reference degrees of eccentricity, in the
direction to the springs having a small number is set to be lower
than the other reference degree of eccentricity in the reverse
direction.
19. The method as set forth in claim 12, wherein the rotations of
the drum in the clockwise and counterclockwise directions are
alternately achieved in the disentanglement of laundry.
20. The method as set forth in claim 12, wherein the rotation of
the motor in the counterclockwise direction is performed after a
designated time from the stop of the rotation of the drum in the
clockwise direction elapses in the disentanglement of laundry.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method for controlling
dehydration of a washing machine, and more particularly, to a
method for controlling dehydration of a washing machine, which
determines whether or not dehydration is performed in consideration
of a difference of vibrations of a tub between rotations of a drum
in clockwise and counterclockwise directions.
[0003] 2. Description of the Related Art
[0004] Generally, a washing machine is an apparatus for removing
contaminants from laundry using functions of a detergent and water.
Recently, various auxiliary devices, such as a drying device for
drying laundry, are connected to a tub of the washing machine.
[0005] FIG. 1 is a longitudinal sectional view of a conventional
washing machine, and FIG. 2 is an exploded perspective view of the
conventional washing machine, front and upper surfaces of which are
opened from a main body of the washing machine.
[0006] The conventional washing machine, as shown in FIGS. 1 and 2,
comprises a casing 2, a tub 10 installed in the casing 2 for
containing wash water, a drum 20 rotatably placed in the tub 10 for
containing laundry (m), a motor 30 for simultaneously supporting
and rotating the drum 20, and a drying device 40 for inhaling air
in the drum 20, condensing and heating the air, circulating the air
into the drum 20 to dry the laundry (m) in the drum 20.
[0007] An opening 2a for allowing the laundry (m) to be put into
and taken out of the casing 2 therethrough is formed through one
surface of the casing 2, and a door 4 for opening and closing the
opening 2a is installed on the casing 2.
[0008] The tub 10 is suspended from springs 5 connected the upper
part of the casing 2, and is mounted on dampers 6 installed on the
lower part of the casing 2, thereby being supported such that shock
imposed on the tub 10 can be absorbed.
[0009] Each of the springs 5 includes a left spring connected to
the upper part of the left side of the casing 2 and the upper part
of the left side of the tub 10, and a right spring connected to the
upper part of the right side of the casing 2 and the upper part of
the right side of the tub 10.
[0010] The number of the left springs and the number of the right
springs of the springs 5 may be the same as each other, or may
differ from each other.
[0011] Each of the dampers 6 includes a left damper connected to
the lower part of the left side of the casing 2 and the lower part
of the left side of the tub 10, and a right spring connected to the
lower part of the right side of the casing 2 and the lower part of
the right side of the tub 10.
[0012] The number of the left dampers and the number of the right
dampers of the dampers 6 may be the same as each other, or may
differ from each other.
[0013] A water supply device 12 for supplying wash water, which is
fed from the outside, to the inside of the tub 10, and a drainage
device 14 for discharging the wash water from the inside of the tub
10 to the outside are connected to the tub 10.
[0014] An opening 21 for allowing the laundry (m), the wash water,
and air to be put into and taken out of the drum 20 therethrough,
and through holes 22 for passing the wash water and the air
therethrough are formed through the drum 20.
[0015] A rotary shaft of the motor 30 passes through the tub 10,
and is supported by the tub 10 by a bearing. A front end of the
rotary shaft of the motor 30 is connected to the drum 20.
[0016] The motor 30 includes a sensing device, such as a hall
sensor, for sensing the rotational frequency (rpm) or rotational
angle thereof.
[0017] The drying device 40 includes a condensing duct 42 connected
to one side of the tub 10, a cooling water nozzle 44 for spraying
cooling water onto the condensing duct 42, and a drying duct 48
communicating with the condensing duct 42 and containing a
circulation fan 45 and a heater 46 for circulating air in a
high-temperature and low-humidity state into the drum 20.
[0018] The washing machine further comprises a controller for
controlling the water supply device 12, the drainage device 14, and
the motor 13 based on user's manipulation or the sensed quantity of
laundry and the sensed degree of eccentricity.
[0019] Hereinafter, the operation of the above conventional washing
machine will be described in detail.
[0020] First, laundry (m) is put into the drum 20, and the door 4
is closed. Thereafter, when the washing machine is operated, the
controller senses the quantity of the laundry (m) in the drum 20,
and sets a wash water level, a washing time, a quantity of a
detergent, and a type of water current, such as a rinsing water
current or a wash water current, based on the sensed quantity of
the laundry (m).
[0021] The controller controls the water supply device 12 based on
the sensed quantity of the laundry (m) for a designated time such
that the wash water is supplied to a designated level in the
washing machine, and the supplied wash water is supplied into the
tub 10. Thereafter, the controller rotates the motor 30 at a
designated rotational frequency for a designated time such that the
drum 20 is rotated by the motor 30, and dirt is removed from the
laundry (m) contained in the drum 20 by the action of the wash
water. After the above-described washing operation is completed,
the contaminated wash water in the tub 10 is discharged to the
outside of the washing machine through the drainage device 14.
[0022] Further, the washing machine performs a rinsing operation
for eliminating foam remaining in the laundry (m) several times. In
the same manner as the washing operation, the controller controls
the water supply device 12 and the motor 30 based on the sensed
quantity of the laundry (m). Then, the contaminated water
containing the foam is discharged to the outside of the washing
machine through the drainage device 14.
[0023] After the repetitions of the rinsing operation are
completed, the washing machine performs a dehydrating operation for
centrifugally dehydrating the laundry (m).
[0024] The dehydrating operation includes sensing the quantity of
the laundry to determine an optimum dehydrating time or an optimum
dehydrating rotational frequency, sensing a degree of eccentricity
to determine whether or not the dehydration operation is performed
or the laundry (m) are disentangled, and main-dehydrating the
laundry (m) by rotating the motor 30 at a high speed after sensing
the quantity of the laundry or sensing the degree of
eccentricity.
[0025] FIG. 3 is a flow chart illustrating a dehydrating operation
of the conventional washing machine.
[0026] As shown in FIG. 3, after the washing or rinsing operation
is completed, the washing machine senses the quantity of the
laundry (m) and senses the degree of eccentricity.
[0027] When sensing the quantity of the laundry (m), the motor 30
starts its operation such that the motor 30 maintains a constant
rotational speed for a designated time, and is turned off. A pulse
width modulation (PWM) duty value from the start of the operation
of the motor 30 to the termination of the maintaining of the
regular rotational speed of the motor 30 and a surplus rotational
angle of the motor 30 after the turn-off of the motor 30 are
measured, thereby sensing the quantity of the laundry (m) (S1).
[0028] When sensing the degree of eccentricity, the motor 30 is
operated such that the drum 20 is rotated in either one direction
of clockwise and counterclockwise directions (for example, the
clockwise direction), and a degree of eccentricity (UB.sub.1) is
sensed during the operation of the motor 30 (S2 and S3).
[0029] Thereafter, in case that the sensed degree of eccentricity
(UB.sub.1) is lower than a reference degree of eccentricity (Pass
UB) for determining whether or not a dehydrating operation starts,
the drum 20 is rotated in the above direction (for example, the
clockwise direction) so that the main dehydration of the laundry
(m) is performed (S4 and S5).
[0030] On the other hand, in case that the sensed degree of
eccentricity (UB.sub.1) is not lower than the reference degree of
eccentricity (Pass UB), it is determined that the degree of
eccentricity (UB.sub.1) is excessive, the disentanglement of the
laundry (m) is performed, and the sense of the degree of
eccentricity is performed again (S6).
[0031] The motor 30 of the washing machine is then rotated in the
reverse direction such that the drum 20 is rotated in the other
direction of clockwise and counterclockwise directions (for
example, the counterclockwise direction), and a degree of
eccentricity (UB.sub.2) is re-sensed using a variation of the
rotational frequency during the reverse operation of the motor 30
(S7 and S3).
[0032] Thereafter, in case that the re-sensed degree of
eccentricity (UB.sub.2) is lower than the reference degree of
eccentricity (Pass UB) for determining whether or not the
dehydrating operation starts, the drum 20 is rotated in the reverse
direction (for example, the counterclockwise direction). On the
other hand, in case that the re-sensed degree of eccentricity
(UB.sub.2) is not lower than the reference degree of eccentricity
(Pass UB), it is determined that the degree of eccentricity
(UB.sub.2) is excessive, the disentanglement of the laundry (m) is
performed again, and the sense of the degree of eccentricity is
performed again. Then, the above-described regular and reverse
rotations of the drum 20, sense of the degree of eccentricity,
comparison, and disentanglement of the laundry (m) are repeated
until subsequent degrees of eccentricity (UB.sub.3, UB.sub.4, . . .
) are lower than the reference degree of eccentricity (Pass
UB).
[0033] The main dehydration of the laundry (m) is performed for an
optimum dehydrating time or at an optimum dehydrating rotational
frequency based on the quantity of the laundry (m) obtained in the
sense of the laundry (m). Here, the laundry is centrifugally
dehydrated at a high speed.
[0034] Thereafter, after the dehydrating operation of the washing
machine is completed, the drying device 40 is operated, thereby
performing a drying operation.
[0035] In case that the tub 10 of the conventional washing machine
is supported by the springs 5 or the dampers 6 such that the tub 10
is bilaterally asymmetrical, vibrations having different degrees
are generated from the rotations of the tub 10 in the clockwise
direction and the counterclockwise direction, thereby causing the
tub 10 or the drying device 40 to collide with the casing 2 and
generating excessive vibration of the washing machine.
[0036] Further, in case that the drying device 40 is installed
eccentrically on one side of left and right sides of the tub 10,
the distance between one side of the drying device 40 and the
casing 2 is shorter than that between the other side of the drying
device 40 and the casing 2, thereby causing the drying device 40 to
easily collide with the casing 2.
[0037] The reference degree of eccentricity Pass (UB), which is set
to a low value in order to prevent the above excessive vibration or
collision, increases the number of the repetitions of the sense of
the degree of eccentricity and the disentanglement of the laundry
(m), thereby causing a failure in performing the dehydrating
operation or lengthening the overall dehydrating time.
SUMMARY OF THE INVENTION
[0038] Therefore, the present invention has been made in view of
the above problems, and it is an object of the present invention to
a method for controlling dehydration of a washing machine, in which
reference degrees of eccentricity of rotations of a drum in the
clockwise and counterclockwise directions are set to different
values, thereby preventing the washing machine from being
excessively vibrated and allowing the washing machine to advance
into a dehydrating operation.
[0039] In accordance with one aspect of the present invention, the
above and other objects can be accomplished by the provision of a
method for controlling dehydration of a washing machine, in which
reference degrees of eccentricity in the clockwise and
counterclockwise direction of a drum, for determining whether or
not main dehydration is performed, are set to different values.
[0040] Preferably, the reference degree of eccentricity in the
direction, in which the vibration of a tub is large, may be set to
be lower than the reference degree of eccentricity in the
direction, in which the vibration of the tub is small.
[0041] Preferably, in case that a drying device is eccentrically
installed at left or right side from the center of a tub, one
reference degree of eccentricity in the direction of installation
of the drying device may be set to be lower than the other
reference degree of eccentricity in the reverse direction.
[0042] Further, preferably, in case that the numbers of dampers
connected to left and right sides of a tub differ from each other,
one reference degree of eccentricity in the direction to the
dampers having a small number may be set to be lower than the other
reference degree of eccentricity in the reverse direction.
[0043] Moreover, preferably, in case that the numbers of springs
connected to left and right sides of a tub differ from each other,
one reference degree of eccentricity in the direction to the
springs having a small number may be set to be lower than the other
reference degree of eccentricity in the reverse direction.
[0044] In accordance with another aspect of the present invention,
there is provided a method for controlling dehydration of a washing
machine, comprising the steps of: (i) rotating a drum in one
direction out of the clockwise and counterclockwise directions, and
sensing a degree of eccentricity; (ii) stopping the rotation of the
drum when the degree of eccentricity sensed in step (i) is not
lower than a first reference degree of eccentricity, and performing
main dehydration when the degree of eccentricity sensed in step (i)
is lower than the first reference degree of eccentricity; (iii)
rotating the drum in the direction reverse to the rotation in step
(i) when the rotation of the drum is stopped in step (ii), and
sensing a degree of eccentricity; and (iv) stopping the rotation of
the drum when the degree of eccentricity sensed in step (iii) is
not lower than a second reference degree of eccentricity set to a
value differing from that of the first reference degree of
eccentricity, and performing main dehydration when the degree of
eccentricity sensed in step (iii) is lower than the second
reference degree of eccentricity, wherein all steps from step (i)
are repeated in case that the rotation of the drum is stopped in
step (iv).
[0045] In accordance with yet another aspect of the present
invention, there is provided a method for controlling dehydration
of a washing machine, comprising the steps of: (i) rotating a drum
in one direction out of the clockwise and counterclockwise
directions, and sensing a degree of eccentricity; (ii) stopping the
rotation of the drum and performing disentanglement of laundry when
the degree of eccentricity sensed in step (i) is not lower than a
first reference degree of eccentricity, and performing main
dehydration when the degree of eccentricity sensed in step (i) is
lower than the first reference degree of eccentricity; (iii)
rotating the drum in the direction reverse to the rotation in step
(i) when the rotation of the drum is stopped and the
disentanglement of laundry is performed in step (ii), and sensing a
degree of eccentricity; and (iv) stopping the rotation of the drum
and performing disentanglement of laundry when the degree of
eccentricity sensed in step (iii) is not lower than a second
reference degree of eccentricity set to a value differing from that
of the first reference degree of eccentricity, and performing main
dehydration when the degree of eccentricity sensed in step (iii) is
lower than the second reference degree of eccentricity, wherein all
steps from step (i) are repeated in case that the rotation of the
drum is stopped and the disentanglement of laundry is performed in
step (iv).
[0046] Preferably, in the sense of the degree of eccentricity, a
motor for rotating the drum may be accelerated such that the
rotational frequency (rpm) of the motor reaches a predetermined
rotational frequency (rpm), the motor may be maintained at a
constant rotational speed for a predetermined time when the
rotational frequency (rpm) of the motor reaches the predetermined
rotational frequency (rpm), and then the motor may be turned off;
and the degree of eccentricity may be sensed using a variation of
the rotational speed (rpm) during a time of maintaining the motor
at the constant speed.
[0047] Preferably, one reference degree of eccentricity, out of the
first and second reference degrees of eccentricity, in the
direction, in which the vibration of a tub is large, is set to be
lower than the other reference degree of eccentricity in the
direction, in which the vibration of the tub is small.
[0048] Further, preferably, in case that a drying device is
eccentrically installed at left or right side from the center of a
tub, one reference degree of eccentricity, out of the first and
second reference degrees of eccentricity, in the direction of
installation of the drying device may be set to be lower than the
other reference degree of eccentricity in the reverse
direction.
[0049] Moreover, preferably, in case that left and right suspension
systems of the tub are bilaterally asymmetric, one reference degree
of eccentricity, out of the first and second reference degrees of
eccentricity, in the direction to the suspension system having
relatively large vibration may be set to be lower than the other
reference degree of eccentricity in the reverse direction.
[0050] Preferably, in case that the numbers of dampers connected to
left and right sides of a tub differ from each other, one reference
degree of eccentricity, out of the first and second reference
degrees of eccentricity, in the direction to the dampers having a
small number may be set to be lower than the other reference degree
of eccentricity in the reverse direction.
[0051] Further, preferably, in case that the numbers of springs
connected to left and right sides of a tub differ from each other,
one reference degree of eccentricity, out of the first and second
reference degrees of eccentricity, in the direction to the springs
having a small number may be set to be lower than the other
reference degree of eccentricity in the reverse direction.
[0052] Preferably, the rotations of the drum in the clockwise and
counterclockwise directions may be alternately achieved in the
disentanglement of laundry.
[0053] Further, preferably, the rotation of the motor in the
counterclockwise direction may be performed after a designated time
from the stop of the rotation of the drum in the clockwise
direction elapses in the disentanglement of laundry.
[0054] In the method of the present invention, one reference degree
of eccentricity in the direction, in which the vibration of the tub
is large, is set to be lower than the other reference degree of
eccentricity in the direction, in which the vibration of the tub is
small, thereby preventing the part of the large vibration of the
tub from performing a dehydrating operation until the reference
degree of eccentricity in the direction to the part of the large
vibration of the tub has a small value so as to prevent the washing
machine from being excessively vibrated, and allowing the part of
the small vibration of the tub to easily perform the dehydrating
operation.
[0055] Further, in the method of the present invention, one
reference degree of eccentricity in the direction to the
installation of a drying device is set to be lower than the other
reference degree of eccentricity in the reverse direction, thereby
preventing the drying device from colliding with a casing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0056] The above and other objects, features and other advantages
of the present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0057] FIG. 1 is a longitudinal sectional view of a conventional
washing machine;
[0058] FIG. 2 is an exploded perspective view of the conventional
washing machine, front and upper surfaces of which are opened from
a main body of the washing machine;
[0059] FIG. 3 is a flow chart illustrating a dehydrating operation
of the conventional washing machine;
[0060] FIG. 4 is a graph illustrating a variation of the rotational
frequency (rpm) of a motor according to a variation of time in a
method for controlling dehydration of a washing machine in
accordance with an embodiment of the present invention; and
[0061] FIG. 5 is a flow chart illustrating the method for
controlling dehydration of a washing machine in accordance with the
embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0062] Now, a preferred embodiment of the present invention will be
described in detail with reference to the annexed drawings.
[0063] FIG. 4 is a graph illustrating a variation of the rotational
frequency (rpm) of a motor according to a variation of time in a
method for controlling dehydration of a washing machine in
accordance with an embodiment of the present invention, and FIG. 5
is a flow chart illustrating the method for controlling dehydration
of a washing machine in accordance with the embodiment of the
present invention.
[0064] The method for controlling the dehydration of the washing
machine in accordance with this embodiment of the present
invention, as shown in FIGS. 4 and 5, comprises sensing a quantity
of laundry (section "a"), sensing a degree of eccentricity
(sections "b" and "b'"), disentangling the laundry to release the
eccentricity of the laundry (section "c"), and dehydrating the
laundry by rotating a drum at a high speed (section "d").
[0065] In the sense of the quantity of the laundry (section "a"), a
motor is accelerated such that the rotational frequency (rpm) of
the motor reaches a first predetermined rotational frequency
(rpm.sub.1), the first predetermined rotational frequency
(rpm.sub.1) of the motor is maintained at a constant rotational
speed for a predetermined time, and then the motor is turned off. A
pulse width modulation (PWM) duty value until the termination of
the maintaining of the constant rotational speed of the motor, and
a surplus rotational angle of the motor after the turn-off of the
motor are measured, thereby sensing the quantity of the laundry
(S11).
[0066] In the sense of the quantity of the laundry, the quantity of
the laundry is obtained by adding a value, obtained by multiplying
the sensed PWM duty value by a proportional constant, to a value,
obtained by multiplying the surplus rotational angle by a
proportional constant.
[0067] Here, the quantity of the laundry may be obtained by
performing the operation of the motor and the calculation once, or
may be obtained by repeating the operation of the motor and the
calculation twice or more and applying resultant values to a
specific equation, for example averaging the resultant values.
[0068] In the sense of the degree of eccentricity (section "b"),
the drum is rotated in either one direction of clockwise and
counterclockwise directions (for example, the counterclockwise
direction) (S12).
[0069] In the sense of the degree of eccentricity (section "b"),
the motor is accelerated such that the rotational frequency (rpm)
of the motor reaches a second predetermined rotational frequency
(rpm.sub.2, here, rpm.sub.2>rpm.sub.1), the second predetermined
rotational frequency (rpm.sub.2) of the motor is maintained at a
constant rotational speed for a predetermined time, and then the
motor is turned off. An rpm ripple for the time of maintaining the
constant rotational speed of the motor is sensed as the degree of
eccentricity (UBccw.sub.1) (S13).
[0070] Thereafter, in case that the sensed degree of eccentricity
(UBccw.sub.1) is lower than a first reference degree of
eccentricity (Pass UBccw), the drum is rotated in the above
direction (for example, the counterclockwise direction) so that the
main dehydration of the laundry (section "d") is performed (S14 and
S15).
[0071] Here, the first reference degree of eccentricity (Pass
UBccw) is a reference degree of eccentricity for determining
whether or not the dehydration of the laundry in the direction of
rotation of the drum starts.
[0072] In the main dehydration of the laundry (section "d"), the
motor is accelerated such that the rotational frequency (rpm) of
the motor reaches a third predetermined rotational frequency
(rpm.sub.3, here, rpm.sub.3>rpm.sub.2) determined by the sensed
quantity of the laundry, the third predetermined rotational
frequency (rpm.sub.3) of the motor is maintained for a time
determined by the sensed quantity of the laundry when the
rotational frequency (rpm) of the motor reaches the third
predetermined rotational frequency (rpm.sub.3), and then the motor
is turned off.
[0073] On the other hand, in case that the sensed degree of
eccentricity (UBccw.sub.1) is not lower than the first reference
degree of eccentricity (Pass UBccw), it is determined that the
degree of eccentricity (UBccw.sub.1) is excessive, and the
disentanglement of the laundry (section "c") is performed
(S16).
[0074] In the disentanglement of the laundry (section "c"), the
motor is operated in regular and reverse directions such that the
drum is alternately rotated in the clockwise and counterclockwise
directions.
[0075] That is, in the disentanglement of the laundry (section
"c"), after a designated time from the stop of the rotation of the
drum in the clockwise direction elapses, the drum is rotated in the
counterclockwise direction.
[0076] After the disentanglement of the laundry (section "c"), the
drum is rotated in the reverse direction of the rotation of the
drum in the initial sense of the degree of eccentricity (for
example, the clockwise direction) (S17).
[0077] Here, the motor is accelerated such that the rotational
frequency (rpm) of the motor reaches the second predetermined
rotational frequency (rpm.sub.2), the second predetermined
rotational frequency (rpm.sub.2) of the motor is maintained at a
constant rotational speed for a predetermined time when the
rotational frequency (rpm) of the motor reaches the second
predetermined rotational frequency (rpm.sub.2), and then the motor
is turned off. Then, a degree of eccentricity (UBcw.sub.1) is
re-sensed (S18).
[0078] In the sense of the degree of eccentricity (section "b'"),
an rpm ripple for the time of maintaining the constant rotational
speed of the motor is sensed as the degree of eccentricity
(UBcw.sub.1).
[0079] Thereafter, in case that the sensed degree of eccentricity
(UBcw.sub.1) is lower than a second reference degree of
eccentricity (Pass UBcw) for determining whether or not the main
dehydration of the laundry starts, the drum is rotated in the above
direction (for example, the clockwise direction) of rotation of the
drum for re-sensing the degree of eccentricity so that the main
dehydration of the laundry (section "d") is performed (S19 and
S15).
[0080] On the other hand, in case that the sensed degree of
eccentricity (UBcw.sub.1) is not lower than the second reference
degree of eccentricity (Pass UBcw), it is determined that the
degree of eccentricity (UBcw.sub.1) is excessive, and the
disentanglement of the laundry (section "c") is performed again
(S20).
[0081] Here, the second reference degree of eccentricity (Pass
UBcw) refers to a reference degree of eccentricity in the direction
of installation of a drying device on the center of the tub, and is
set to be lower than the first reference degree of eccentricity
(pass UBccw) in the reverse direction.
[0082] That is, in case that the drying device is eccentrically
installed at left or right side from the center of the tub, when
severe vibration is generated from the direction of the
installation of the drying device from the center of the tub (for
example, the clockwise direction), the drying device collides with
a casing. Accordingly, the reference degree of eccentricity (Pass
UBcw) in the direction of installation of the drying device (for
example, the clockwise direction) is set to be smaller than the
reference degree of eccentricity (Pass UBccw) in the reverse
direction (for example, the counterclockwise direction), and the
dehydration of laundry in the direction of installation of the
drying device is not performed until the sensed degree of
eccentricity in the direction of installation of the drying device
(for example, the clockwise direction) has a small value, thereby
minimizing the collision between the drying device and the casing,
and causing the reference degree of eccentricity (Pass UBccw) in
the reverse direction (for example, the counterclockwise direction)
to have a relatively large value, thus facilitating the start of
the dehydration of the laundry.
[0083] Further, the second reference degree of eccentricity (Pass
UBcw) is a reference degree of eccentricity in the direction (for
example, the clockwise direction), in which the vibration of the
tub is large, out of the clockwise and counterclockwise directions
of the drum, and is set to be lower than the first reference degree
of eccentricity (pass UBccw).
[0084] That is, in case that the numbers of dampers for supporting
left and right sides of the lower part of the tub differ from each
other or the numbers of springs for supporting left and right sides
of the upper part of the tub differ from each other, left and right
suspension systems of the tub are bilaterally asymmetric so that
different vibrations are generated from left and right parts of the
tub. When the reference degree of eccentricity (Pass UBcw) in the
direction to the suspension system having a relatively large
vibration is set to be lower than the reference degree of
eccentricity (Pass UBccw) in the direction to the other suspension
system, and the dehydration of laundry in the direction to the part
of the large vibration is not performed until the sensed degree of
eccentricity in the direction to the part of the large vibration
(for example, the clockwise direction) has a small value, thereby
preventing severe vibration from being generated in one direction
out of the left and right directions, and causing the reference
degree of eccentricity (Pass UBccw) in the reverse direction to the
part of the small vibration (for example, the counterclockwise
direction) to have a relatively large value, thus facilitating the
start of the dehydration of the laundry.
[0085] After the disentanglement of the laundry (section "c") is
performed again, the washing machine repeats the above rotation of
the drum in the clockwise/counterclockwise directions, the sense of
the degree of eccentricity (sections "b" and "b'"), the comparison,
and the disentanglement of the laundry (section "c").
[0086] That is, after the disentanglement of the laundry (section
"c") is performed again, the drum 20 is rotated in the same
direction (for example, the counterclockwise direction) as the
rotation of the drum in the initial sense of the degree of
eccentricity, and the degree of eccentricity is re-sensed, and, in
case that the re-sensed degrees of eccentricity (UBccw.sub.2,
UBccw.sub.3, . . . ) are lower than the first reference degree of
eccentricity (Pass UBccw), the main dehydration of the laundry is
performed in the above rotational direction. Then, the drum 20 is
rotated in the direction (for example, the clockwise direction)
reverse to the rotation of the drum in the initial sense of the
degree of eccentricity, and the degree of eccentricity is
re-sensed, and, in case that the re-sensed degrees of eccentricity
(UBccw.sub.2, UBccw.sub.3, . . . ) are lower than the second
reference degree of eccentricity (Pass UBcw), the main dehydration
of the laundry is performed in the above rotational direction.
[0087] As apparent from the above description, the present
invention provides a method for controlling dehydration of a
washing machine, in which one reference degree of eccentricity in
the direction, in which the vibration of the tub is large, tub is
set to be lower than the other reference degree of eccentricity in
the direction, in which the vibration of the tub is small, thereby
preventing the part of the large vibration of the tub from
performing a dehydrating operation until the reference degree of
eccentricity in the direction to the part of a large vibration of
the tub has a small value so as to prevent the washing machine from
being excessively vibrated, and allowing the part of the small
vibration of the tub to easily perform the dehydrating
operation.
[0088] Further, in the method of the present invention, one
reference degree of eccentricity in the direction to the
installation of a drying device is set to be lower than the other
reference degree of eccentricity in the reverse direction, thereby
preventing the drying device from colliding with a casing.
[0089] Although the preferred embodiment of the present invention
has been disclosed for illustrative purposes, those skilled in the
art will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying
claims.
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