U.S. patent application number 13/392599 was filed with the patent office on 2012-06-21 for control method of laundry machine.
Invention is credited to Jae Hyuk Jang, Bon Kwon Koo.
Application Number | 20120151687 13/392599 |
Document ID | / |
Family ID | 43628190 |
Filed Date | 2012-06-21 |
United States Patent
Application |
20120151687 |
Kind Code |
A1 |
Jang; Jae Hyuk ; et
al. |
June 21, 2012 |
CONTROL METHOD OF LAUNDRY MACHINE
Abstract
The control method of a laundry machine comprises re-performing
a laundry distributing step in case unbalance generated in a front
portion of a drum is sensed in at least one step of an accelerating
step and a unbalance sensing step.
Inventors: |
Jang; Jae Hyuk; (Seoul,
KR) ; Koo; Bon Kwon; (Seoul, KR) |
Family ID: |
43628190 |
Appl. No.: |
13/392599 |
Filed: |
August 27, 2010 |
PCT Filed: |
August 27, 2010 |
PCT NO: |
PCT/KR10/05809 |
371 Date: |
February 27, 2012 |
Current U.S.
Class: |
8/137 |
Current CPC
Class: |
D06F 37/24 20130101;
D06F 2222/00 20130101; D06F 37/22 20130101; D06F 37/304 20130101;
D06F 33/00 20130101; D06F 37/203 20130101; D06F 2204/065
20130101 |
Class at
Publication: |
8/137 |
International
Class: |
D06L 1/20 20060101
D06L001/20 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 27, 2009 |
KR |
10-2009-0079912 |
Aug 27, 2009 |
KR |
10-2009-0079923 |
Aug 27, 2009 |
KR |
10-2009-0080126 |
Claims
1. A control method of a laundry machine comprising: re-performing
a laundry distributing step in case unbalance generated in a front
portion of a drum is sensed in at least one step of an accelerating
step and a unbalance sensing step.
2. The control method as claimed in claim 1, wherein it is
determined, based on vibration sensed in the drum, whether the
front portion unbalance of the drum is generated.
3. The control method as claimed in claim 2, wherein it is
determined, based on a forward/rearward vibration sensed in the
drum, whether the front portion unbalance of the drum is
generated.
4. The control method as claimed in claim 2, wherein the sensing of
the vibration is implemented at higher a RPM of the drum than a
transient region.
5. The control method as claimed in claim 4, wherein the sensing of
the vibration is implemented when the drum is rotated at a constant
speed.
6. The control method as claimed in claim 4, wherein the sensing of
the vibration is implemented in a region of the RPM from 350 to 400
RPM.
7. A control method of a laundry machine comprising: sensing an
amount of the unbalance; identifying a position of the unbalance
inside a drum; and re-performing a laundry distributing step based
on the sensed unbalance amount and the unbalance position inside
the drum.
8. The control method as claimed in claim 7, wherein the laundry
distributing step is re-implemented in case the sensed unbalance is
a reference unbalance value or more or in case unbalance is
generated in a front portion of the drum.
9. The control method as claimed in claim 8, wherein it is
determined based on a forward/rearward vibration value of the drum
whether the front portion unbalance is generated in the drum.
10. A control method of a laundry machine comprising: sensing an
amount of the unbalance; identifying a position of the unbalance
inside a drum; and adjusting an allowable reference unbalance value
allowing acceleration of a drum rotation speed based on the
unbalance position of the drum
11. The control method as claimed in claim 10, wherein the
unbalance position of the drum is determined based on a
forward/rearward vibration value of the drum.
12. The control method as claimed in claim 11, wherein a reference
unbalance value allowing acceleration of a drum rotation speed is
set differently according to unbalance generated in a front
portion, center portion or rear portion of the drum.
13. The control method as claimed in claim 12, wherein the
reference unbalance value set for the unbalance generated in the
front portion of the drum is substantially smaller than the
reference unbalance value set to the unbalance generated in the
rear portion of the drum.
14. The control method as claimed in claim 1, wherein the laundry
machine comprises a driving unit comprising a shaft connected to a
drum, a bearing housing to rotatably support the shaft, and a motor
to rotate the shaft, and a suspension assembly is connected to the
driving unit.
15. The control method as claimed in claim 1, wherein the laundry
machine comprises a rear gasket for sealing to prevent washing
water from leaking from a space between a driving unit and a tub,
and enabling the driving unit movable relative to the tub.
16. The control method as claimed in claim 1, wherein a tub is
supported rigidly more than a drum being supported by a suspension
assembly.
Description
TECHNICAL FIELD
[0001] The present invention relates to a control method of a
laundry machine.
BACKGROUND ART
[0002] In general, a laundry machine may include washing, rinsing
and spinning cycles. Here, the spinning cycle includes a rotating
step of rotating a drum provided in such a laundry machine at the
highest RPM. Because of the step, the spinning cycle would generate
noise and vibration quite a lot, which is required to be solved in
the art the prevent invention pertains to.
DISCLOSURE OF INVENTION
Technical Problem
[0003] Accordingly, the present invention is directed to a control
method of a laundry machine.
[0004] An object of the present invention is to provide a control
method of a laundry machine which can solve the above problem.
Solution to Problem
[0005] To solve the problems, an object of the present invention is
to provide a control method of a laundry machine comprising
re-performing a laundry distributing step in case unbalance
generated in a front portion of a drum is sensed in at least one
step of an accelerating step and a unbalance sensing step.
Advantageous Effects of Invention
[0006] The present invention has following advantageous
effects.
[0007] In case the spinning cycle is implemented according to the
control method of the present invention, noise and vibration
generated in the laundry machine may be reduced and the time of the
spinning cycle may be reduced simultaneously.
BRIEF DESCRIPTION OF DRAWINGS
[0008] The accompanying drawings, which are included to provide
further understanding of the disclosure and are incorporated in and
constitute a part of this application, illustrate embodiments of
the disclosure and together with the description serve to explain
the principle of the disclosure.
[0009] In the drawings:
[0010] FIG. 1 is an exploded perspective view illustrating a
laundry machine a spinning cycle control method according to the
present invention is applied to;
[0011] FIG. 2 is a sectional view illustrating a connecting state
of FIG. 1;
[0012] FIG. 3 is a graph illustrating RPM change according to the
spinning cycle control method of the present invention;
[0013] FIG. 4 is a graph showing a relation of mass vs. a natural
frequency; and
[0014] FIG. 5 is a graph illustrating vibration characteristics of
the laundry machine of FIG. 2
BEST MODE FOR CARRYING OUT THE INVENTION
[0015] According to a laundry machine according to an embodiment,
the tub may be fixedly supported to the cabinet or it may be
supplied to the cabinet by a flexible supporting structure such as
a suspension unit which will be described later. Also, the
supporting of the tub may be between the supporting of the
suspension unit and the completely fixed supporting.
[0016] That is, the tub may be flexibly supported by the suspension
unit which will be described later or it may be complete-fixedly
supported to be movable more rigidly. Although not shown in the
drawings, the cabinet may not be provided unlike embodiments which
will be described later. For example, in case of a built-in type
laundry machine, a predetermined space in which the built-in type
laundry machine will be installed may be formed by a wall structure
and the like, instead of the cabinet. In other words, the built-in
type laundry machine may not include a cabinet configured to define
an exterior appearance thereof independently.
[0017] In reference to FIGS. 1 and 2, a tub 12 provided in the
laundry machine is fixedly supported to a cabinet. The tub 12
includes a tub front 100 configured to define a front part of the
tub and a tub rear 120 configured to define a rear part of the tub.
The tub front 100 and the tub rear 120 are assembled to each other
by screws, to form a predetermined space big enough to accommodate
the drum. The tub rear 120 has an opening formed in a rear portion
thereof and an inner circumference of the rear portion composing
the tub rear 120 is connected with an outer circumference of a rear
gasket 250. The tub back 130 has a through-hole formed in a center
thereof to pass a shaft to pass there through. The rear gasket 250
is made of a flexible material not to transmit the vibration of the
tub back 130 to the tub rear 120.
[0018] The tub rear 120 has a rear surface 128 and the rear surface
128, the tub back 130 and the rear gasket 250 may define a rear
wall of the tub. The rear gasket 250 is connectedly sealed with the
tub back 130 and the tub rear 120, such that the wash water held in
the tub may not leak. The tub back 130 is vibrated together with
the drum during the rotation of the drum. At this time, the tub
back 130 is distant from the tub rear 120 enough not to interfere
with the tub rear. Since the rear gasket 250 is made of the
flexible material, the tub back 130 is allowed to relative-move,
without interference of the tub rear 120. The rear gasket 250 may
include a corrugated portion 252 extendible to a predetermined
length to allow the relative-motion of the tub back 130.
[0019] A foreign substance preventing member 200 configured to
prevent foreign substances from drawn between the tub and the drum
may be connected to a front portion of the tub front 100. The
foreign substance preventing member 200 is made of a flexible
material and it is fixed to the tub front 100. Here, the foreign
substance preventing member 200 may be made of the flexible
material identical to the material composing the rear gasket 250.
Hereinafter, the foreign substance preventing member 200 will be
referenced to as `front gasket`.
[0020] The drum 32 includes a drum front 300, a drum center and a
drum back 340. Balancers 310 and 330 may be installed in front and
rear parts of the drum, respectively. The drum back 340 is
connected with a spider 350 and the spider 350 is connected with
the shaft 351. The drum 32 is rotated in the tub 12 by a torque
transmitted via the shaft 351.
[0021] The shaft 351 is directly connected with a motor 170,
passing through the tub back 130. Specifically, a rotor 174
composing the motor 170 is directly connected with the shaft 351. a
bearing housing 400 is secured to a rear portion of the tub back
130 and the bearing housing 400 rotatably supports the shaft,
located between the motor 170 and the tub back 130.
[0022] A stator 172 composing the motor 170 is secured to the
bearing housing 400 and the rotor 174 is located surrounding the
stator 172. As mentioned above, the rotor 174 is directly connected
with the shaft 351. Here, the motor 170 is an outer rotor type
motor and it is directly connected with the shaft 351.
[0023] The bearing housing 400 is supported via a suspension unit
with respect to a cabinet base 600. The suspension unit 180
includes three perpendicular supporters and two oblique supporters
configured to support the bearing housing 400 obliquely with
respect to a forward and rearward direction.
[0024] The suspension unit 180 may includes a first cylinder spring
520, a second cylinder spring 510, a third cylinder spring 500, a
first cylinder damper 540 and a second cylinder damper 530.
[0025] The first cylinder spring 520 is connected between a first
suspension bracket 450 and the cabinet base 600. The second
cylinder spring 510 is connected between a suspension bracket 440
and the cabinet base 600.
[0026] The third cylinder spring 500 is directly connected between
the bearing housing 400 and the cabinet base 600.
[0027] The first cylinder damper 540 is inclinedly installed
between the first suspension bracket 450 and a rear portion of the
cabinet base. The second cylinder damper 530 is inclinedly
installed between the second suspension bracket 440 and a rear
portion of the cabinet base 600.
[0028] The cylinder springs 520, 510 and 500 of the suspension unit
180 may be elastically connected to the cabinet base 600 enough to
allow a forward/rearward and rightward/leftward movement of the
drum, not connected to the cabinet base 600 fixedly. That is, they
are elastically supported by the base 600 to allow the drum to be
rotated to a predetermined angle in forward/rearward and
rightward/leftward directions with respect to the connected
portion.
[0029] The perpendicular ones of the suspension unit may be
configured to suspend the vibration of the drum elastically and the
oblique ones may be configured to dampen the vibration. That is, in
a vibration system including a spring and damping means, the
perpendicular ones are employed as spring and the oblique ones are
employed as damping means.
[0030] The tub front 100 and the tub rear 120 are fixedly secured
to the cabinet 110 and the vibration of the drum 32 is suspendedly
supported by the suspension unit 180. The supporting structure of
the tub 12 and the drum 32 may be called `separated` substantially,
such that the tub 12 may not be vibrated even when the drum 32 is
vibrated.
[0031] The bearing housing 400 and the suspension brackets may be
connected with each other by first and second weights 431 and
430.
[0032] In case the drum 30 and 32 is rotated after the laundry 1 is
loaded in the drum 30 and 32 of the laundry machine according to
the above embodiments, quite severe noise and vibration may be
generated according to the position of the laundry 1. For example,
when the drum 30 and 32 is rotated in a state of the laundry not
distributed in the drum 30 and 32 uniformly (hereinafter,
`unbalanced rotatio`), much noise and vibration may be generated.
Especially, if the drum 30 and 32 is rotated at a high speed to
spin the laundry, the noise and vibration may be problematic.
[0033] Because of that, the laundry machine may include the
balancer 310 and 330 configured to prevent the noise and vibration
generated by the unbalanced rotation of the drum 32. According to
this embodiment, a front balancer 310 is mounted to a front portion
of the drum and a rear balancer 320 is mounted to a rear portion of
the drum. A front mounting groove (not shown) is recessed rearward
from the front portion of the drum to mount the front balancer 310
therein and a rear mounting groove (not shown) is recessed forward
from the rear portion of the drum to mount the rear balancer 320
therein.
[0034] According to this embodiment, the front balancer 310 is
identical to the rear balancer 320. However, it is not necessary to
mount the identical balancers to the front and rear portions of the
drum, respectively.
[0035] The balancers are mounted to the drum 30 and 32 to reduce
the unbalance. Because of that, the balancer may have a movable
gravity center. For example, the balancer may include movable
bodies having a predetermined weight located therein and a passage
the movable bodies move along. If the balancers may be ball
balancers, the balancer 70, 310 and 330 may include balls 72, 312
and 332 having a predetermined weight located therein and a passage
the ball moves along.
[0036] The balancers 310 and 320 have predetermined inner spaces to
form a passage of the balls 312 and 332. Here, the number of the
balls located in the inner spaces and the radii of the balls may be
determined in consideration of the unbalance amount to reduce and
the vibration property of the laundry machine.
[0037] In addition, oil (not shown) is filled in the inner spaces.
The amount and the viscosity of the filled oil may affect the
movement of the balls. Because of that, the amount and viscosity of
the oil may be determined for the balls of the balancer to have the
required movement. Also, the vibration property of the laundry
machine may be put into the consideration when determining
that.
[0038] More specifically, the balls are rotated by the friction
generated during the rotation of the drum 30 and 32 and they are
not kept unmovable in the drum when the drum is rotated. Because of
that, the balls are rotated at a different speed from the rotation
speed of the drum. Here, the laundry which generates the unbalance
may be rotated at the almost same speed as the speed of the drum
because of the friction generated by the close contact with an
inner circumferential surface of the drum and the lifters provided
in the inner circumferential surface. As a result, the rotation
speed of the laundry is different from that of the balls. The
rotation speed of the laundry is higher than that of the balls
during an initial rotation stage in which the drum is rotated at a
relatively low speed, specifically, a rotation angle speed of the
laundry is higher. In addition, a phase difference between the
balls and the laundry, which is a phase difference with respect to
a rotation center of the drum, may changes continuously.
[0039] Hence, when the rotation speed of the drum is getting
higher, the balls may be in close contact with an outer
circumferential surface of the passage by the centrifugal force. At
the same time, the balls are aligned at a predetermined position
having approximately 90.degree. to 180.degree. of the phase
difference with respect to the laundry. If the rotation speed of
the drum is a predetermined value or more, the centrifugal force is
getting larger and the friction generated between the outer
circumferential surface and the balls is a predetermined value or
more and the balls may be rotated at the same speed as the drum. at
this time, the balls are rotated at the same speed as the drum,
with maintaining the position having the 90.degree. to 180.degree.,
preferably, approximately 180.degree. of the phase difference with
respect to the laundry. In this specification of the present
invention, the rotation of the balls at the predetermined positions
as mentioned above may be expressed as `unbalance corresponding
position` or `balancing`.
[0040] As a result, in case load is concentrated on a predetermined
portion of the drum inside by the laundry, the ball located in the
balancer 70, 310 and 330 may move to an unbalance corresponding
position to reduce the unbalance.
[0041] As follows, a control method of the laundry machine having
the above configuration according to the above embodiments will be
described. typically, the laundry machine includes washing, rinsing
and spinning cycles and the control method according to the present
invention which is be applicable to the spinning cycle will be
described in reference to corresponding drawings.
[0042] FIG. 3 is a graph illustrating RPM change of the drum as the
time passes according to the control method of the spinning cycle.
According to FIG. 3, a horizontal axis is `time` and a vertical
axis is `rotation speed` of the drum 30 and 32 which is change of
RPM.
[0043] In reference to FIG. 3, the spinning cycle control method
according to the present invention includes a laundry distributing
step (S100) and a spinning step (S200).
[0044] The laundry distributing step (S100) distributes the laundry
uniformly, as rotating the drum at a relatively low speed. The
spinning cycle (S200) rotates the drum at a relatively high speed
to remove moisture contained in the laundry. Here, such the laundry
distributing step and spinning step are named with respect to main
functions thereof. The functions of the steps may not be limited to
the names. For example, the laundry distributing step may remove
the moisture of the laundry by using the rotation of the drum, as
well as the laundry distributing.
[0045] The laundry distributing step (S100) composing the control
method according to the present invention may include a wet laundry
sensing step (S110), a laundry disentangling step (S130) and an
unbalance sensing step (S150). The spinning step (S200) may include
a transient region passing step (S210) and an accelerating step
(S230). As follows, each one of the above steps will be
described.
[0046] Once the rinsing cycle is completed, the laundry located in
the drum 30 and 32 is wet by the moisture. A control part senses
the amount of the laundry, that is, the amount of the wet laundry
located in the drum 30 and 32, when the spinning cycle is put into
operation (S110).
[0047] The reason why the amount of the wet laundry is that the
amount of the dry laundry measured in an initial stage of the
washing cycle is different from the amount of the wet laundry
containing the moisture. The sensed amount of the wet laundry may
be used as an element configured to determine an allowable
condition of the drum accelerating or to determine to re-implement
the laundry distributing step after decreasing the speed of the
drum 30 and 32 based on an unbalance condition in the transient
region passing step (S210).
[0048] According to the control method of the present invention,
the amount of the wet laundry located in the drum 30 and 32 is
measured in case the drum is rotated at a decreased speed after
rotated at a constant speed of approximately 100 to 110 RPM reached
by the acceleration for a predetermined time period. If the
rotation speed of the drum is decreased, rheostatic braking is
used. Specifically, the amount of the wet laundry is measured by
using the amount of acceleration period rotation in accelerating
the motor 40 and 170 configured to rotate the drum 30 and 32, the
amount of the acceleration period rotation in decreasing the speed
of the motor 40 and 170, and an applied DC voltage.
[0049] After measuring the amount of the wet laundry, the control
part may implement the laundry disentangling step (S130) configured
to distribute the laundry inside the drum uniformly.
[0050] The laundry disentangling step distributes the laundry
located in the drum 30 and 32 uniformly to prevent the laundry from
concentrated on a specific region inside the drum, which might
increase the unbalance. If the unbalance is increased, noise and
vibration will be increased in case the RPM of the drum is
heightened. The laundry disentangling step accelerates the drum in
a predetermined single direction with a predetermined oblique and
it is implemented until the RPM reaches a rotation speed of the
unbalance sensing step which will be described later.
[0051] Hence, the control part senses the unbalance of the drum
(S150).
[0052] If the laundry is concentrated on a specific region inside
the drum 30 and 32, not distributed uniformly, the unbalance is
increased and the nose and vibration will be generated when the RPM
of the drum 30 and 32 is heightened. Because of that, the control
part senses the unbalance of the drum and it determines whether the
drum is accelerated.
[0053] The unbalance sensing uses difference of the accelerated
speeds during the rotation of the drum 30 and 32. That is, there is
difference of the accelerated speeds when the drum is rotated
downward along the gravity and when it is rotated upward reversely
according to the level of the generated unbalance. The control part
measures the difference of the accelerated speeds by using a speed
sensor, for example, a hall sensor provided in the motor 40 and 170
to sense the amount of the unbalance. In case the unbalance is
sensed, the laundry located inside the drum keeps the close contact
with the inner circumferential surface of the drum, without dropped
from the inner circumferential surface, even during the rotation of
the drum. The case having the drum rotated at approximately 100 to
110 RPM is corresponding to this case.
[0054] If the drum is accelerated at a high speed in case the
sensed unbalance amount of the drum having a predetermined amount
of wet laundry is a reference unbalance value or more, the
vibration and noise of the drum will increase remarkably and it is
difficult to accelerate the speed of the drum. Because of that, the
control part may store a reference unbalance value, which allows
the acceleration of the speed according to the amount of the wet
laundry as a table typed data. After that, the control part applies
the sensed wet-laundry amount and the unbalance amount to the table
and it determines whether the speed of the drum is accelerated. In
other words, in case the unbalance amount sensed according to the
sensed wet-laundry amount is the reference unbalance value or more,
it can be determined that the unbalance amount is too much to
accelerate the drum speed and the above wet-laundry sensing,
laundry disentangling and unbalance sensing steps are repeated.
[0055] As mentioned above, the repetition of the wet laundry
sensing step, the laundry disentangling step and the unbalance
sensing step may be continued until the sensed unbalance amount
meets less than the reference unbalance value. However, if the
laundry machine is in an abnormal state or the laundry is entangled
severely inside the drum, the sensed unbalance amount cannot meet
less tan the reference unbalance value and the steps may be
repeated. As a result, it is preferable that the control part
controls the drum to stop the rotation and notifies the user that
the spinning cycle is not completed normally, if the speed of the
drum fails to be accelerated for a predetermined time period, for
example, approximately more than 20 to 30 minutes after the
spinning cycle starts.
[0056] In case the unbalance amount sensed according to the sensed
wet laundry amount is less than the reference unbalance amount, the
RPM accelerating condition is satisfied and the control part
implements the transient region passing step (S210).
[0057] Here, the transient region is a predetermined RPM band
including at least one resonance frequency which generates
resonance according to the system of the laundry machine. When the
system of the laundry machine is determined, the transient region
is a unique vibration property generated according to the
determined system. The transient region is variable according to
the system of the laundry machine. For example, the transient
region includes a scope of approximately 200 to 270 RPM in the
laundry according to the first embodiment and a scope of
approximately 200 to 350 RPM in the laundry machine according to
the second embodiment.
[0058] FIG. 4 illustrates a graph showing a relation of mass vs. a
natural frequency. It is assumed that, in vibration systems of two
laundry machines, the two laundry machines have mass of m0 and m1
respectively and maximum holding laundry amounts are .DELTA.m,
respectively. Then, the transition regions of the two laundry
machines can be determined taking .DELTA.nf0 and .DELTA.nf1 into
account, respectively. In this instance, amounts of water contained
in the laundry will not be taken into account, for the time
being.
[0059] In the meantime, referring to FIG. 4, the laundry machine
with smaller mass m1 has a range of the transition region greater
than the laundry machine with greater mass m0. That is, the range
of the transition region having variation of the laundry amount
taken into account becomes the greater as the mass of the vibration
system becomes the smaller.
[0060] The ranges of the transition regions will be reviewed on the
related art laundry machine and the laundry machine of the
embodiment.
[0061] The related art laundry machine has a structure in which
vibration is transmitted from the drum to the tub as it is, causing
the tub to vibrate. Therefore, in taking the vibration of the
related art laundry machine into account, the tub is indispensible.
However, in general, the tub has, not only a weight of its own, but
also substantial weights at a front, a rear or a circumferential
surface thereof for balancing. Accordingly, the related art laundry
machine has great mass of the vibration system.
[0062] Opposite to this, in the laundry machine of the embodiment,
since the tub, not only has no weight, but also is separated from
the drum in view of a supporting structure, the tub may not be put
into account in consideration of the vibration of the drum.
Therefore, the laundry machine of the embodiment may have
relatively small mass of the vibration system.
[0063] Then, referring to FIG. 4, the related art laundry machine
has mass m0 and the laundry machine of the embodiment has mass m1,
leading the laundry machine of the embodiment to have a greater
transition region, at the end.
[0064] Moreover, if the amounts of water contained in the laundry
are taken into account simply, .DELTA.m in FIG. 4 will become
greater, making a range difference of the transition regions even
greater. And, since, in the related art laundry machine, the water
drops into the tub from the drum even if the water escapes from the
laundry as the drum rotates, an amount of water mass reduction come
from the spinning is small. Since the laundry machine of the
embodiment has the tub and the drum separated from each other in
view of vibration, the water escaped from the drum influences the
vibration of the drum, instantly. That is, the influence of a mass
change of the water in the laundry is greater in the laundry
machine of the embodiment than the related art laundry machine.
[0065] Under above reason, though the related art laundry machine
has the transition region of about 200.about.270 rpm, A start RPM
of the transient region of the laundry machine according to this
embodiment may be similar to a start RPM of the transient region of
the conventional laundry machine. An end RPM of the transient
region of the laundry machine according to this embodiment may
increase more than a RPM calculated by adding a value of
approximately 30% of the start RPM to the start RPM. For example,
the transient region finishes at an RPM calculated by adding a
value of approximately 80% of the start RPM to the start RPM.
According to this embodiment, the transient region may include a
RPM band of approximately 200 to 350 rpm.
[0066] In the meantime, by reducing intensity of the vibration of
the drum, unbalance may be reduced. For this, even laundry
spreading is performed for spreading the laundry in the drum as far
as possible before the rotation speed of the drum enters into the
transition region.
[0067] In a case, a balancer is used, a method may be put into
account, in which the rotation speed of the drum passes through the
transition region while movable bodies provided in the balancer are
positioned on an opposite side of an unbalance of the laundry. In
this instance, it is preferable that the movable bodies are
positioned at exact opposite of the unbalance in middle of the
transition region.
[0068] However, as described above, the transient region of the
laundry machine according to this embodiment is relatively wide in
comparison to that of the conventional laundry machine. Because of
that, even if the laundry even-spreading step or ball balancing is
implemented in a RPM band lower than the transient region, the
laundry might be in disorder or balancing might be failed with the
drum speed passing the transient region.
[0069] As a result, balancing may be implemented at least one time
in the laundry machine according to this embodiment before and
while the drum speed passing the transient region. Here, the
balancing may be defined as rotation of the drum at a
constant-speed for a predetermined time period. Such the balancing
allows the movable body of the balancer to the opposite positions
of the laundry, only to reduce the unbalance amount. By extension,
the effect of the laundry even-spreading. Eventually, the balancing
is implemented while the drum speed passing the transient region
and the noise and vibration generated by the expansion of the
transient region may be prevented.
[0070] Here, when the balancing is implemented before the drum
speed passing the transient region, the balancing may be
implemented in a different RPM band from the RPM of the
conventional laundry machine. For example, if the transient region
starts at 200 RPM, the balancing is implemented in the RPM band
lower than approximately 150 RPM. Since the conventional laundry
machine has a relatively less wide transient region, it is not so
difficult for the drum speed to pass the transient region even with
the balancing implemented at the RPM lower than approximately 150
RPM. However, the laundry machine according to this embodiment has
the relatively wide expanded transient region as described above.
if the balancing is implemented at the such the low RPM like in the
conventional laundry machine, the positions of the movable bodies
might be in disorder by the balancing implemented with the drum
speed passing the transient region. Because of that, the laundry
machine according to this embodiment may increase the balancing RPM
in comparison to the conventional balancing RPM, when the balancing
is implemented before the drum speed enters the transient region.
That is, if the start RPM of the transient region is determined,
the balancing is implemented in a RPM band higher than a RPM
calculated by subtracting a value of approximately 25% of the start
RPM from the start RPM. For example, the start RPM of the transient
region is approximately 200 RPM, the balancing may be implemented
in a RPM band higher than 150 RPm lower than 200 RPM.
[0071] Moreover, the unbalance amount may be measured during the
balancing. That is, the control method may further include a step
to measure the unbalance amount during the balancing and to compare
the measured unbalance amount with an allowable unbalance amount
allowing the acceleration of the drum speed. If the measured
unbalance amount is less than the allowable unbalance amount, the
drum speed is accelerated after the balancing to be out of the
transient region. In contrast, if the measured unbalance amount is
the allowable unbalance amount or more, the laundry even-spreading
step may be re-implemented. in this case, the allowable unbalance
amount may be different from an allowable unbalance amount allowing
the initial accelerating.
[0072] That is, in case the rotation speed of the drum 32 passes
the transient region, the resonance is generated in the laundry
machine and noise and vibration of the laundry machine are
generated remarkably. The noise and vibration of the laundry
machine will give an unpleasant feeling to the user and they will
interfere with the acceleration of the drum speed. As a result, in
case the rotation speed of the drum passes the transient region, an
acceleration inclination may be adjusted appropriately in the
transient region and to noise and vibration may be maintained as
little as possible during the acceleration of the drum 32.
[0073] After the transient region passing step, the control part
implements the accelerating step (S230). Once passing the transient
region, the RPM of the drum 32 is accelerated at a relatively high
speed to remove water elements from the laundry. In other words,
the RPM of the drum 32 is increased to a predetermined value and
the moisture of the laundry inside the drum 32 is removed, in the
accelerating step (S230). However, the accelerating step increases
the RPM of the drum 32 at the high speed and noise and vibration
will be generated a lot in the laundry machine. Especially, the
noise and vibration may be increasing in proportion to the
unbalance amount of the drum 32.
[0074] In the meanwhile, the laundry machine having the spinning
cycle control method applied thereto may include the balancer 310
and 330 configured to prevent the noise and vibration generated by
unbalance. The balls provided in the balancer 310 and 330 are
configured move to the unbalance corresponding positions to reduce
the unbalance amount. Here, the balls of the balancer may moveable
more smoothly in the normal RPM than the accelerated speed and in
the relatively slow speed than in the high speed. Because of that,
if the drum 32 is accelerated at the relatively high speed, the
balls cannot move to the unbalance corresponding positions
smoothly. The spinning cycle control method may include a step of
moving the balls to move to the unbalance corresponding positions,
passing the transient region, namely, a balancing step.
[0075] In this case, the RPM used to implement the balancing may be
set to be higher than the transient region of the laundry machine.
The balancing is more and more advantageous to implement, as the
RPM of the drum 32 is getting lower. However, if the RPM is
decreased below the transient region again to implement the
balancing, the noise and vibration may be generated by resonance.
As a result, the first balancing of the control method may be
implemented at a second RPM (RPM 2), for example, 350 to 400
RPM.
[0076] After the balancing step, the control part increases the RPM
of the drum 32 to a target RPM, to remove the moisture from the
laundry. Then, the control part controls the normal rotation of the
drum to be embodied at the target RPM for a predetermined time
period such that it may remove the moisture from the laundry
smoothly.
[0077] In the meanwhile, for the spinning step (S200) to follow the
laundry distributing step (S100), the unbalance amount of the drum
has to be less than the reference unbalance amount as mentioned
above.
[0078] If the reference unbalance amount is set to be too large,
the noise and vibration will be increased while the rotation speed
of the drum is passing the transient region. Especially, when the
target RPM is reached in the spinning step, the noise and vibration
may be remarkably increased. In contrast, if the reference
unbalance amount is set to be too small, the noise and vibration
could be reduced in the following process and it takes too much
time from the end of the laundry distributing step (S100) to the
start of the spinning step (S200). In other words, if the reference
unbalance amount is too small, the sensed unbalance amount fails to
be less than the reference unbalance amount and the wet laundry
sensing, laundry disentangling and unbalance sensing steps would be
repeated. This may result in the increase of the spinning cycle and
in the user's complaint.
[0079] Because of that, according to the control method of the
present invention, the reference unbalance mount is set to be
relatively high to reduce the time between the finish of the
laundry distributing step (S100) and the start of the spinning step
(S200), with reducing the noise and vibration in the following step
simultaneously.
[0080] Specifically, when the reference unbalance amount allowing
the acceleration of the unbalance sensing step (S150) is set
relatively high, it is more efficient and smooth to finish the
laundry distributing step (S100) and to enter into the spinning
step (S200). Because of that, the time taken to start the spinning
step (S200) from the laundry distributing step (S100) may be
reduced. As follows, the method of reducing the noise and vibration
in the following step will be described.
[0081] The drum 32 is connected with the tub back 130 in the
laundry machine having the vibration of the tub separated from that
of the drum. The tub back 130 is supported by the suspension unit
180 via the bearing housing 400, not by the tub 12. as a result,
compared with the conventional laundry machine in which the tub
back 130 supports the load of the drum 120, directly connected with
the tub 120, the drum 32 provided in the laundry machine according
to the present invention may have large freedom. Especially, the
freedom of the front portion of the drum 32 may be increased. If
unbalance is generated in the front portion of the drum because of
the laundry concentrated on the front portion of the drum 32
(hereinafter, `drum front unbalance`), vibration generated in the
front portion of the drum 32 happens to be large. Because of that,
it is very important to determine whether unbalance is located in
the front portion of the drum 32, rather than to distribute the
laundry concentrated in the front portion of the drum and to
compensate the unbalance in case unbalance is generated in the
laundry machine having the vibration of the tub separated from that
of the drum.
[0082] For that, the laundry machine includes a vibration sensor
and the vibration sensor senses a vibration value of the drum, to
determine the position of the unbalance generation inside the drum
32. In other words, if unbalance is generated by the laundry
concentrated on the front portion of the drum in the laundry
machine having the vibration of the tub separated from that of the
drum, vibration will be increased and then the control may sense
the value transmitted from the vibration sensor. In case the sensed
vibration is a predetermined value or more, the control part may
determine that unbalance is generated in the front portion of the
drum 32 and the control part may determine unbalance generated in
center and rear portions of the drum based on the vibration value
transmitted from the vibration sensor.
[0083] In the meanwhile, the vibration sensor may be located in the
rear portion of the drum 32 and it may sense the vibration of the
drum 32. Especially, freedom of the front portion of the drum is
increased in the laundry machine having the vibration of the tub
separated from that of the drum as mentioned above and. because of
that, if upward/downward vibration and forward/rearward vibration
of the drum are generated, compared with rightward and leftward
vibration, the freedom of the drum front portion will be increased.
When the drum front unbalance is generated, vibration values of the
drum in upward/downward and forward/rearward directions may
relatively large. The control part may be determined the generation
of the drum front unbalance based on the upward/downward vibration
value and/or the forward/rearward vibration value.
[0084] In the meanwhile, both or either of the upward/downward
vibration and the forward/rearward vibration mentioned above may be
sensed may be sensed according to the kind of the vibration sensor
provided in the laundry machine, to determine the unbalance
generation position.
[0085] In the meanwhile, it is preferable that the rotation speed
(RPM 2) configured to sense vibration to detect the unbalance
generation position of the drum may be higher than the transient
region. Much noise and vibration of the drum could be generated by
resonance in the transient region. Because of that, in case the
vibration of the drum is increased up to a predetermined value or
more, it is difficult to determine whether the vibration is
generated by the resonance or the drum unbalance position. As a
result, the second rotation speed (RPM 2) may be higher the
transient region, for example, 350 to 400 RPM. Since the unbalance
position of the drum is detected by the vibration sensor, the drum
may be rotated normally at a predetermined speed for the accurate
vibration sensing. With rotating the drum in a brand of 350 to 400
RPM out of the transient region, the control part controls the
vibration sensor to sense the vibration value. In case the sensed
vibration value is a predetermined value or more, the control part
determines that unbalance is generated in the front portion of the
drum. If the unbalance is generated in the front portion of the
drum based on the result of the determination, the control part may
re-implement the laundry distributing step (S100).
[0086] The drum front unbalance sensing of the vibration sensor may
be implemented in the balancing step (S232) described above. The
rotation speed of the balancing step (S232) is approximately 350 to
400 RPM as described above and the step is in a constant speed
operation period, such that it is possible for the vibration sensor
to sense the drum front unbalance.
[0087] The vibration sensing step configured to detect the
unbalance position of the drum described above according to the
control method may be implemented in both of the unbalance sensing
step and the accelerating step. In other words, the unbalance
sensing step senses unbalance and it compares the sensed unbalance
with the reference unbalance amount allowing the acceleration of
the drum speed. Also, the unbalance position of the drum is sensed
based on the vibration value of the drum and the laundry
distributing step is re-implemented. Here, when the sensed
unbalance amount is more than the reference unbalance amount or the
drum front unbalance is generated, the laundry distributing step is
re-implemented without starting the spinning step. Here, the method
of detecting the unbalance position of the drum in the unbalance
sensing step is similar to the method of detecting the unbalance
position in the accelerating step and repeated description will be
omitted accordingly.
[0088] In the meanwhile, in the control method according to another
embodiment of the present invention, the reference unbalance amount
allowing the acceleration of the drum speed may be adjusted based
on the unbalance position of the drum. In other words, if unbalance
is generated in each of the front, center and rear portions of the
drum, the reference unbalance amount allowing the acceleration of
the drum at each position may be determined differently. In this
case, the reference unbalance amount in case unbalance is generated
in the front portion of the drum is the smallest and the reference
unbalance amount in case unbalance is generated in the rear portion
of the drum is the largest. And the reference unbalance amount in
case unbalance is generated in the center portion of the drum is
approximately a middle value of the two. As a result, the reference
unbalance amount is differentiated according to the unbalance
generation position of the drum and it may be possible to reduce
the noise generated in the following step.
[0089] First, vibration characteristics of the laundry machine
according to the embodiment of the present invention will now be
described with reference to FIG. 5.
[0090] As the rotation speed of the drum is increased, a region
(hereinafter, referred to as "transient vibration region") where
irregular transient vibration with high amplitude occurs is
generated. The transient vibration region irregularly occurs with
high amplitude before vibration is transited to a steady-state
vibration region (hereinafter, referred to as "steady-state
region"), and has vibration characteristics determined if a
vibration system (laundry machine) is designed. Though the
transient vibration region is different according to the type of
the laundry machine, transient vibration occurs approximately in
the range of 200 rpm to 270 rpm. It is regarded that transient
vibration is caused by resonance. Accordingly, it is necessary to
design the balancer by considering effective balancing at the
transient vibration region.
[0091] In the mean time, as described above, in the laundry machine
according to the embodiment of the present invention, the vibration
source, i.e., the motor and the drum connected with the motor are
connected with the tub 12 through the rear gasket 250. Accordingly,
vibration occurring in the drum is little forwarded to the tub, and
the drum is supported by a damping means and the suspension unit
180 via a bearing housing 400. As a result, the tub 12 can directly
be fixed to a cabinet 110 without any damping means.
[0092] As a result of studies of the inventor of the present
invention, vibration characteristics not observed generally have
been found in the laundry machine according to the present
invention. According to the general laundry machine, vibration
(displacement) becomes steady after passing through the transient
vibration region. However, in the laundry machine according to the
embodiment of the present invention, a region (hereinafter,
referred to as "irregular vibration") where vibration becomes
steady after passing through the transient vibration region and
again becomes great may be generated. For example, if the maximum
drum displacement or more generated in an RPM band lower than the
transient region or the maximum drum displacement or more of steady
state step in a RPM band higher than the transient region is
generated, it is determined that irregular vibration is generated.
Alternatively, if an average drum displacement in the transient
region, +20% to -20% of the average drum displacement in the
transient region or 1/3 or more of the maximum drum displacement in
the natural frequency of the transient region are generated, it may
be determined that the irregular vibration is generated.
[0093] However, as a result of the studies, irregular vibration has
occurred in a RPM band higher than the transient region, for
example has occurred at a region (hereinafter, referred to as
"irregular vibration region") in the range of 350 rpm to 1000 rpm,
approximately. Irregular vibration may be generated due to use of
the balancer, the damping system, and the rear gasket. Accordingly,
in this laundry machine, it is necessary to design the balancer by
considering the irregular vibration region as well as the transient
vibration region.
[0094] For example, the balancer is provide with a ball balancer,
it is preferable that the structure of the balancer, i.e., the size
of the ball, the number of balls, a shape of the race, viscosity of
oil, and a filling level of oil are selected by considering the
irregular vibration region as well as the transient vibration
region. When considering the transient vibration region and/or the
irregular vibration region, especially considering the irregular
vibration region, the ball balancer has a greater diameter of 255.8
mm and a smaller diameter of 249.2. A space of the race, in which
the ball is contained, has a sectional area of 411.93 mm2. The
number of balls is 14 at the front and the rear, respectively, and
the ball has a size of 19.05 mm. Silicon based oil such as Poly
Dimethylsiloxane (PDMS) is used as the oil. Preferably, oil has
viscosity of 300 CS at a room temperature, and has a filling level
of 350 cc.
[0095] In addition to the structure of the balancer, in view of
control, it is preferable that the irregular vibration region as
well as the transient vibration region is considered. For example,
to prevent the irregular vibration, if the irregular vibration
region is determined, the balancing may be implemented at least one
time before, while and after the drum speed passes the irregular
vibration region. Here, if the rotation speed of the drum is
relatively high, the balancing of the balancer may not be
implemented properly and the balancing may be implemented with
decreasing the rotation speed of the drum. however, if the rotation
speed of the drum is decreased to be lower than the transient
region to implement the balancing, it has to pass the transient
region again. In decreasing the rotation speed of the drum to
implement the balancing, the decreased rotation speed may be higher
than the transient region.
[0096] It will be apparent to those skilled in the art that various
modifications and variations can be made in the present invention
without departing from the spirit or scope of the invention. Thus,
it is intended that the present invention cover the modifications
and variations of this invention provided they come within the
scope of the appended claims and their equivalents.
INDUSTRIAL APPLICABILITY
[0097] The present invention has an industrial applicability.
[0098] In case the spinning cycle is implemented according to the
control method of the present invention, noise and vibration
generated in the laundry machine may be reduced and the time of the
spinning cycle may be reduced simultaneously.
* * * * *