U.S. patent application number 15/576592 was filed with the patent office on 2018-06-07 for dewatering machine.
The applicant listed for this patent is AQUA CO., LTD., QINGDAO HAIER WASHING MACHINE CO., LTD.. Invention is credited to Tomonari KAWAGUCHI, Hiroki SATO.
Application Number | 20180155862 15/576592 |
Document ID | / |
Family ID | 55018398 |
Filed Date | 2018-06-07 |
United States Patent
Application |
20180155862 |
Kind Code |
A1 |
KAWAGUCHI; Tomonari ; et
al. |
June 7, 2018 |
Dewatering Machine
Abstract
A dewatering machine including an electric motor for rotating a
dewatering drum and a control part. When the dewatering drum starts
to rotate, the control part measures a load of the washings in the
dewatering drum. Then, the control part rotates the motor at a
first rotating speed by controlling a duty ratio of a voltage
applied to the motor and then to rotates the motor at a second
rotating speed higher than the first rotating speed. When the motor
accelerates to the first rotating speed, the control part acquires
a reference duty ratio at timing determined according to the
measured load. Next, within a specified period, the control part
determines whether the washings in the dewatering drum are biased
according to an index indicating the change between the duty ratio
and the reference duty ratio.
Inventors: |
KAWAGUCHI; Tomonari; (Tokyo,
JP) ; SATO; Hiroki; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AQUA CO., LTD.
QINGDAO HAIER WASHING MACHINE CO., LTD. |
Tokyo
Qingdao, Shandong |
|
JP
CN |
|
|
Family ID: |
55018398 |
Appl. No.: |
15/576592 |
Filed: |
May 26, 2016 |
PCT Filed: |
May 26, 2016 |
PCT NO: |
PCT/CN2016/083395 |
371 Date: |
November 22, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D06F 35/005 20130101;
D06F 2204/10 20130101; D06F 2204/065 20130101; D06F 23/04 20130101;
D06F 33/00 20130101; D06F 34/18 20200201; D06F 2222/00
20130101 |
International
Class: |
D06F 23/04 20060101
D06F023/04; D06F 33/02 20060101 D06F033/02 |
Foreign Application Data
Date |
Code |
Application Number |
May 26, 2015 |
JP |
2015-106538 |
Claims
1. A dewatering machine, comprising: a dewatering drum configured
to accommodate washings and rotate to dewater the washings; an
electric motor configured to rotate the dewatering drum; a load
measuring unit configured to measure a load of the washings in the
dewatering drum when the dewatering drum begins to rotate; a drive
control unit configured to, after the load measuring unit measures
the load, rotate the motor constantly at a first rotating speed by
controlling a duty ratio of a voltage applied to the motor and then
rotate the motor constantly at a second rotating speed higher than
the first rotating speed so as to dewater the washings formally; an
acquisition unit configure to acquire the duty ratio of the voltage
applied to the motor as a reference duty ratio in an acceleration
state in which the motor accelerates to the first rotating speed; a
timing determination unit configured to determine timing for the
acquisition unit to acquire the reference duty ratio; a
determination unit configured to, in a specified period after the
acquisition unit acquires the reference duty ratio, determine
whether the washings in the dewatering drum are biased or not
according to an index indicating a change between a duty ratio of
the voltage applied to the motor to maintain the first rotating
speed and the reference duty ratio; and a stopping control unit
configured to stop the rotation of the dewatering drum when the
determination unit determines that the washings are biased, wherein
the timing determination unit determines the timing for the
acquisition unit to acquire the reference duty ratio according to
the load measured by the load measuring unit.
2. The dewatering machine according to claim 1, wherein the
dewatering machine comprises an execution unit configured to, after
the stopping control unit stops the rotation of the dewatering
drum, execute one of the following executions: a rotation of the
dewatering drum for restart the dewatering of the washings and a
processing for correcting the bias of the washings in the
dewatering drum.
3. The dewatering machine according to claim 2, wherein before the
motor rotates constantly at the first rotating speed, the drive
control unit rotates the motor constantly at a specified speed
lower than the first rotating speed; and the execution unit
shortens the duration in which the motor rotates constantly at the
specified speed when the execution unit executes the rotation of
the dewatering drum for restart the dewatering of the washings.
4. A dewatering machine, comprising: a dewatering drum configured
to accommodate washings and rotate to dewater the washings; an
electric motor configured to rotate the dewatering drum; a drive
control unit configured to rotate the motor constantly at a first
rotating speed by controlling a duty ratio of a voltage applied to
the motor and then rotate the motor constantly at a second rotating
speed higher than the first rotating speed so as to dewater the
washings formally; an acquisition unit configured to acquire a duty
ratio every a specified time within a specified period after the
motor begins to accelerate to the first rotating speed; a counting
unit configured to add 1 to a count value with an initial value of
zero when the duty ratio acquired by the acquisition unit is
greater than or equal to the duty ratio acquired last time and
reset the count value to the initial value when the duty ratio
acquired by the acquisition unit is smaller than the duty ratio
acquired last time; a determination unit configured to determine
that the washings in the dewatering drum are biased when the count
value is greater than or equal to a specified threshold; and a
stopping control unit configured to stop the rotation of the
dewatering drum when the determination unit determines that the
washings are biased.
5. A dewatering machine, comprising: a dewatering drum configured
to accommodate washings and rotate to dewater the washings; an
electric motor configured to rotate the dewatering drum; a drive
control unit configured to rotate the motor constantly at a first
rotating speed by controlling a duty ratio of a voltage applied to
the motor and then rotate the motor constantly at a second rotating
speed higher than the first rotating speed so as to dewater the
washings formally; an acquisition unit configured to acquire a duty
ratio every a specified time within a period when the rotating
speed of the motor accelerates from the first rotating speed to a
second rotating speed; a determination unit configured to determine
that the washings in the dewatering drum are biased when the duty
ratio acquired by the acquisition unit is greater than or equal to
a specified threshold; a stopping control unit configured to stop
the rotation of the dewatering drum when the determination unit
determines that the washings are biased; a receiving unit
configured to receive a selection related to a dewatering condition
of the washings; and a threshold changing unit configured to change
the threshold according to the selection related to the dewatering
condition received by the receiving unit.
6. A dewatering machine, comprising: a dewatering drum configured
to accommodate washings and rotate to dewater the washings; an
electric motor configured to rotate the dewatering drum; a drive
control unit configured to rotate the motor constantly at a first
rotating speed by controlling a duty ratio of a voltage applied to
the motor and then rotate the motor constantly at a second rotating
speed higher than the first rotating speed so as to dewater the
washings formally; an acquisition unit configured to acquire a
maximum value of a duty ratio in an acceleration state in which the
motor accelerates to the first rotating speed to serve as a maximum
duty ratio; a calculation unit configured to calculate an
accumulated value of a difference between the duty ratio in every
specified time and the maximum duty ratio after the acquisition
unit acquires the maximum duty ratio; a determination unit
configured to determine that the washings in the dewatering drum
are biased when the accumulated value is smaller than the specified
threshold; and a stopping control unit configured to stop the
rotation of the dewatering drum when the determination unit
determines that the washings are biased.
7. The dewatering machine according to claim 6, wherein the
threshold is calculated using an equation adopting a count value
and the maximum duty ratio as variables, wherein the count value is
added by 1 once every the specified time.
8. The dewatering machine according to claim 6, wherein the drive
control unit controls the duty ratio in the following way: in the
acceleration state in which the motor accelerates to the first
rotating speed, the drive control unit generates the maximum duty
ratio when the rotating speed is slightly lower than a rotating
speed at which the dewatering drum resonates.
9. The dewatering machine according to claim 7, wherein the drive
control unit controls the duty ratio in the following way: in the
acceleration state in which the motor accelerates to the first
rotating speed, the drive control unit generates the maximum duty
ratio when the rotating speed is slightly lower than a rotating
speed at which the dewatering drum resonates.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a dewatering machine.
BACKGROUND
[0002] A patent literature 1 discloses a washing machine with a
dewatering function. During the dewatering of washings in the
washing machine, a motor, which rotates a washing and dewatering
drum accommodating the washings and to which a voltage with a
controlled duty ratio is applied, rotates at a constant speed of
120 rpm, then rotates at a constant speed of 240 rpm, and finally
rotates at a constant speed of 800 rpm.
[0003] When the washings in the washing and dewatering drum are
subjected to the dewatering operation in an imbalance state of
being biased and configured in a circumferential direction of the
washing and dewatering drum, vibration and noise are increased.
Therefore, whether the washings in the washing and dewatering drum
are biased is detected in the washing machine.
[0004] Specifically, the duty ratio at a time point when 3.6
seconds are elapsed after the motor starts to accelerate from 120
rpm to 240 rpm is taken as a reference duty ratio. In addition, a
target value related to the duty ratio which changes over time in a
state that the motor rotates at the constant speed of 240 rpm is
used as a comparative duty ratio and is calculated based on the
reference duty ratio. Moreover, when a difference between an actual
duty ratio obtained once at every specified timing and the
comparative duty ratio at the same timing in the state where the
motor rotates at the constant speed of 240 rpm is greater than a
specified threshold value, it is determined that the washings are
biased, and the rotation of the motor is stopped.
CURRENT TECHNICAL LITERATURE
Patent Literature
[0005] Patent Literature 1: Japanese Laid-Open Patent Publication
No. 2011-240040
Problems to be Solved by the Disclosure
[0006] The washing machine in the patent literature 1 determines
that a rotating speed of the motor reaches 240 rpm at the time
point when 3.6 seconds are elapsed after the motor starts to
accelerate from 120 rpm to 240 rpm, and the duty ratio at the time
point is regarded as the reference duty ratio.
[0007] However, since time required for the rotating speed of the
motor to reach 240 rpm may change based on the load of the washings
in the washing and dewatering drum, the time is not necessarily
limited to the above 3.6 seconds.
[0008] The reference duty ratio is an important factor which
affects accuracy for detecting whether the washings are biased.
However, in the case of the patent literature 1, the duty ratio at
the time point when 3.6 seconds are elapsed after the motor starts
to accelerate is always regarded as the reference duty ratio,
irrespective of the load. Therefore, the reference duty ratio,
which is a duty ratio acquired at timing deviating from the correct
timing due to the influence of the load, has an negative impact on
the accuracy for detecting whether the washings are biased.
[0009] In addition, in the case of a structure for detecting
whether the washings are biased, a problem to be solved for long is
to shorten the time for the dewatering operation.
SUMMARY
[0010] The present disclosure is a dewatering machine completed in
the background described above, and aims at providing a dewatering
machine capable of improving detection accuracy of bias of
washings.
[0011] In addition, the present disclosure also aims at providing a
dewatering machine capable of shortening duration of dewatering
operation.
Solution for Solving the Problems
[0012] The present disclosure provides a dewatering machine,
including: a dewatering drum for accommodating washings and
rotating to dewater the washings; an electric motor for rotating
the dewatering drum; a load measuring unit for measuring a load of
the washings in the dewatering drum when the dewatering drum begins
to rotate; a drive control unit for, after the load measuring
measures the load, rotating the motor constantly at a first
rotating speed by controlling a duty ratio of a voltage applied to
the motor and then rotating the motor constantly at a second
rotating speed higher than the first rotating speed so as to
dewater the washings formally; an acquisition unit for acquiring
the duty ratio of the voltage applied to the motor as a reference
duty ratio in an acceleration state in which the motor accelerates
to the first rotating speed; a timing determination unit for
determining timing for the acquisition unit to acquire the
reference duty ratio; a determination unit for determining whether
the washings in the dewatering drum are biased or not according to
an index indicating a change between a duty ratio of the voltage
applied to the motor to maintain the first rotating speed and the
reference duty ratio within a specified period after the
acquisition unit acquires the reference duty ratio; and a stopping
control unit for stopping the rotation of the dewatering drum in a
case where the determination unit determines that the washings are
biased, wherein the timing determination unit determines the timing
for the acquisition unit to acquire the reference duty ratio
according to the load measured by the load measuring unit.
[0013] In addition, in the present disclosure, the dewatering
machine includes an execution unit for, in a case where the
stopping control unit enables the dewatering drum to stop rotating,
executing one of the following executions: a rotation of the
dewatering drum for restart the dewatering of the washings and a
processing for correcting the bias of the washings in the
dewatering drum.
[0014] In addition, in the present disclosure, before the motor
rotates constantly at the first rotating speed, the drive control
unit rotates the motor constantly at a specified speed lower than
the first rotating speed, and the execution unit shortens the
duration in which the motor rotates constantly at the specified
speed in a case where the execution unit executes the rotation of
the dewatering drum for restart the dewatering of the washings.
[0015] In addition, the present disclosure provides a dewatering
machine, including: a dewatering drum for accommodating washings
and rotating to dewater the washings; an electric motor for
rotating the dewatering drum; a drive control unit for rotating the
motor constantly at a first rotating speed by controlling a duty
ratio of a voltage applied to the motor and then rotating the motor
constantly at a second rotating speed higher than the first
rotating speed so as to dewater the washings formally; an
acquisition unit for acquiring a duty ratio every a specified time
within a specified period after the motor begins to accelerate to
the first rotating speed; a counting unit for adding 1 to a count
value with an initial value of zero when the duty ratio acquired by
the acquisition unit is greater than or equal to the duty ratio
acquired last time and resetting the count value to the initial
value when the duty ratio acquired by the acquisition unit is
smaller than the duty ratio acquired last time; a determination
unit for determining that the washings in the dewatering drum are
biased when the count value is greater than or equal to a specified
threshold; and a stopping control unit for stopping the rotation of
the dewatering drum in a case where the determination unit
determines that the washings are biased.
[0016] In addition, the present disclosure provides a dewatering
machine, including: a dewatering drum for accommodating washings
and rotating to dewater the washings; an electric motor for
rotating the dewatering drum; a drive control unit for rotating the
motor constantly at a first rotating speed by controlling a duty
ratio of a voltage applied to the motor and then rotating the motor
constantly at a second rotating speed higher than the first
rotating speed so as to dewater the washings formally; an
acquisition unit for acquiring a duty ratio every a specified time
within a period when the rotating speed of the motor accelerates
from the first rotating speed to a second rotating speed; a
determination unit for determining that the washings in the
dewatering drum are biased when the duty ratio acquired by the
acquisition unit is greater than or equal to a specified threshold;
a stopping control unit for stopping the rotation of the dewatering
drum in a case where the determination unit determines that the
washings are biased; a receiving unit for receiving a selection
related to a dewatering condition of the washings; and a threshold
changing unit for changing the threshold according to the selection
related to the dewatering condition received by the receiving
unit.
[0017] In addition, the present disclosure provides a dewatering
machine, including: a dewatering drum for accommodating washings
and rotating to dewater the washings; an electric motor for
rotating the dewatering drum; a drive control unit for rotating the
motor constantly at a first rotating speed by controlling a duty
ratio of a voltage applied to the motor and then rotating the motor
constantly at a second rotating speed higher than the first
rotating speed so as to dewater the washings formally; an
acquisition unit for acquiring a maximum value of a duty ratio in
an acceleration state in which the motor accelerates to the first
rotating speed to serve as a maximum duty ratio; a calculation unit
for calculating an accumulated value of a difference between the
duty ratio in every specified time and the maximum duty ratio after
the acquisition unit acquires the maximum duty ratio; a
determination unit for determining that the washings in the
dewatering drum are biased when the accumulated value is smaller
than the specified threshold; and a stopping control unit for
stopping the rotation of the dewatering drum in a case where the
determination unit determines that the washings are biased.
[0018] In addition, in the present disclosure, the threshold value
is calculated using an equation adopting a count value and the
maximum duty ratio as variables, wherein the count value is added
by 1 once every the specified time.
[0019] In addition, in the present disclosure, the drive control
unit controls the duty ratio in the following way: in the
acceleration state in which the motor accelerates to the first
rotating speed, the drive control unit generates the maximum duty
ratio when the rotating speed is slightly lower than a rotating
speed at which the dewatering drum resonates.
Effects of the Disclosure
[0020] Through the present disclosure, as the dewatering machine
performing the dewatering operation controls the duty ratio of the
voltage applied to the electric motor which rotates the dewatering
drum, the motor rotates constantly at the first rotating speed, and
then the motor rotates constantly at the second rotating speed
higher than the first rotating speed. Thus, the washings in the
dewatering drum are dewatered formally.
[0021] In association with the detection of the bias of the
washings in the dewatering drum, the reference duty ratio is
acquired by the acquisition unit in an acceleration state in which
the motor accelerates to the first rotating speed. Then, after the
acquisition unit acquires the reference duty ratio, within a
specified period, whether the washings in the dewatering drum are
biased or not is determined according to an index indicating the
change between the duty ratio of the voltage applied to the motor
to maintain the first rotating speed and the reference duty ratio.
In the case where the washings are determined to be biased, the
rotation of the dewatering drum is stopped.
[0022] As a detection step of the bias, when the dewatering drum
begins to rotate, a load of the washings in the dewatering drum is
measured, and a timing determination unit determines timing for the
acquisition unit to acquire the reference duty ratio according to
the measured load. Thus, since the reference duty ratio is acquired
at the correct timing in consideration of the load, the detection
of the bias of the washings can be accurately executed on the basis
of the reference duty ratio. The result is that the accuracy for
detecting whether the washings are biased is improved.
[0023] In addition, through the present disclosure, in a case where
the rotation of the dewatering drum is stopped according to the
determination that the washings are biased, either of the rotation
of the dewatering drum for restart the dewatering of the washings
and the processing for correcting the bias of the washings in the
dewatering drum can be selectively executed according to the index
indicating the change between the duty ratio between the reference
duty ratio.
[0024] That is, when the washings are determined to be biased, the
processing for correcting the bias of the washings is not
necessarily executed. Therefore, when the index is an index
indicating that the washings are slightly biased, the dewatering
drum is immediately rotated so as to restart the dewatering,
thereby shortening the dewatering operation time.
[0025] In addition, through the present disclosure, in the
dewatering operation including a step of rotating the motor
constantly at the specified speed lower than the first rotating
speed, in a case where the rotation of the dewatering drum for
restart the dewatering of the washings is executed, since the
duration of the step is shortened, the dewatering time is further
shortened.
[0026] In addition, through the present disclosure, as the
dewatering machine performing the dewatering operation controls the
duty ratio of the voltage applied to the electric motor which
rotates the dewatering drum, the motor rotates constantly at the
first rotating speed, and then the motor rotates constantly at the
second rotating speed higher than the first rotating speed. Thus,
the washings in the dewatering drum are dewatered formally.
[0027] In association with the detection of the bias of the
washings in the dewatering drum, after the motor begins to
accelerate to the first rotating speed, a duty ratio is acquired
every a specified time within a specified period, and each duty
ratio is compared with the duty ratio acquired last time.
Specifically, when the acquired duty ratio is greater than or equal
to the duty ratio acquired last time, the count value with an
initial value of zero is added by 1, and when the acquired duty
ratio is smaller than the duty ratio acquired last time, the count
value is reset to the initial value.
[0028] Moreover, when the count value is greater than or equal to
the specified threshold, the washings in the dewatering drum are
determined to be biased, and the rotation of the dewatering drum is
stopped.
[0029] As long as the change between duty ratios obtained at
adjacent timings is always monitored as described above, even if
the change between the duty ratio and the initial duty ratio
acquired at the beginning of the detection is small, the accurate
detection for acquiring the change of the duty ratio during the
detection in real time can also be performed, so that the accuracy
for detecting whether the washings are biased can be improved.
[0030] In addition, through the present disclosure, as the
dewatering machine performing the dewatering operation controls the
duty ratio of the voltage applied to the electric motor which
rotates the dewatering drum, the motor rotates constantly at the
first rotating speed, and then the motor rotates constantly at the
second rotating speed higher than the first rotating speed. Thus
the washings in the dewatering drum are dewatered formally.
[0031] In association with the detection of the bias of the
washings in the dewatering drum, within the period where the
rotating speed of the motor accelerates from the first rotating
speed to the second rotating speed, a duty ratio is acquired every
the specified timing. When the duty ratio is greater than or equal
to the specified threshold, the washings in the dewatering drum are
determined to be biased, and the rotation of the dewatering drum is
stopped.
[0032] The dewatering machine may receive a selection related to a
dewatering condition of the washings via the receiving unit and may
change the threshold according to the received dewatering
condition. Thus, since the bias of the washings can be detected
through the threshold adaptive to the dewatering condition in the
dewatering operation under various dewatering conditions, the
accuracy for detecting whether the washings are biased can be
improved.
[0033] In addition, through the present disclosure, as the
dewatering machine operates the dewatering operation controls the
duty ratio of the voltage applied to the electric motor which
rotates the dewatering drum, the motor rotates constantly at the
first rotating speed, and then the motor rotates constantly at the
second rotating speed higher than the first rotating speed. Thus,
the washings in the dewatering drum are dewatered formally.
[0034] In association with the detection of the bias of the
washings in the dewatering drum, a maximum value of the duty ratio
is acquired to serve as the maximum duty ratio in the acceleration
state where the motor accelerates to the first rotating speed, and
then an accumulated value of the difference between the maximum
duty ratio and the duty ratio of every specified timing is
calculated.
[0035] In a case where the washings in the dewatering drum are not
biased and after the maximum duty ratio is generated, since the
motor can also accelerate to the first rotating speed even if the
duty ratio is relatively small, the duty ratio is gradually
reduced. Thus, since the difference between the duty ratio and the
maximum duty ratio is gradually increased, the accumulated value is
increased. However, in a case where the washings in the dewatering
drum are biased, since the motor must increase the duty ratio after
generating the maximum duty ratio in order to accelerate to the
first rotating speed, the duty ratio after the maximum duty ratio
is generated can hardly decrease. Thus, since the difference
between the duty ratio and the maximum duty ratio can hardly
increase, the accumulated value can hardly increase.
[0036] Therefore, when the accumulated value is smaller than the
specified threshold, the washings in the dewatering drum are
determined to be biased, and the rotation of the dewatering drum is
stopped.
[0037] As long as a novel structure for monitoring the relative
change between the duty ratio generated after the maximum duty
ratio and the maximum duty ratio is adopted, the accuracy for
detecting whether the washings are biased can be improved.
[0038] In addition, through the present disclosure, the threshold
value is calculated using an equation adopting the count value
added by 1 once every the specified timing and the maximum duty
ratio as variables. The maximum duty ratio varies according to the
load of the washings in the dewatering drum. Therefore, the
threshold value is set differently according to the load. Thus,
since whether the washings are biased is detected according to the
optimum threshold corresponding to the load of the washings in the
dewatering drum, false detection can be prevented. Therefore, the
accuracy for detecting whether the washings are biased is further
improved.
[0039] In addition, through the present disclosure, the duty ratio
is set in such a manner that the maximum duty ratio is generated
when the rotating speed is slightly lower than the rotating speed
at which the dewatering drum resonates. At this moment, the
resonance occurs early after the maximum duty ratio is generated.
Therefore, a phenomenon that the accumulated value is difficult to
increase appears soon. Hence, the bias of the washings in the
dewatering drum can be early and correctly detected.
BRIEF DESCRIPTION OF DRAWINGS
[0040] FIG. 1 is a schematic longitudinal sectional right view
illustrating a dewatering machine 1 of an embodiment of the present
disclosure;
[0041] FIG. 2 is a block diagram illustrating an electric structure
of a dewatering machine 1.
[0042] FIG. 3 is a time chart illustrating a state of a rotating
speed of a motor 6 in a dewatering operation implemented by a
dewatering machine 1.
[0043] FIG. 4 is a diagram illustrating a relationship between a
weight of washings accommodated in a dewatering drum 4 of a
dewatering machine 1 and a load detected by a dewatering machine 1
according to the weight of the washings;
[0044] FIG. 5A is a flow chart illustrating an outline of
detections 1 to 4 for detecting whether washings in a dewatering
drum 4 are biased in dewatering operation;
[0045] FIG. 5B is a flow chart illustrating an outline of
detections 1 to 4 for detecting whether washings in a dewatering
drum 4 are biased in dewatering operation;
[0046] FIG. 6A is a flow chart illustrating control actions related
to detections 1 and 2;
[0047] FIG. 6B is a flow chart illustrating control actions related
to detections 1 and 2;
[0048] FIG. 7 is a graph illustrating a relationship between a
rotating speed of a motor 6 and a difference Sn of a rotating speed
in association with detection 1;
[0049] FIG. 8 is a graph illustrating a relationship between a
rotating speed of a motor 6 and an accumulated value U of an
absolute value of a difference about a difference S in association
with detection 2;
[0050] FIG. 9A is a flow chart illustrating control actions related
to detections 3 and 4;
[0051] FIG. 9B is a flow chart illustrating control actions related
to detections 3 and 4;
[0052] FIG. 10 is a graph illustrating a relationship between time
and a first count value E in association with detection 3;
[0053] FIG. 11 is a graph illustrating a relationship between time
and a corrected duty ratio dn_diff in association with detection
4;
[0054] FIG. 12 is a flow chart illustrating an outline of
detections 5-1 and 5-2 for detecting whether washings in a
dewatering drum 4 are biased in dewatering operation;
[0055] FIG. 13 is a flow chart illustrating control actions related
to detection 5-1;
[0056] FIG. 14 is a graph illustrating a relationship between a
rotating speed and a moving accumulated value Cn in association
with detections 5-1 and 5-2;
[0057] FIG. 15 is a flow chart illustrating control actions related
to detection 5-2;
[0058] FIG. 16 is a flow chart illustrating a control action of
detecting foam in dewatering operation;
[0059] FIG. 17 is a time chart illustrating a state of a rotating
speed of a motor 6 during dewatering operation implemented by a
dewatering machine 1 in association with detection 6;
[0060] FIG. 18 is a flow chart illustrating control actions related
to detection 6;
[0061] FIG. 19 is a graph illustrating a relationship between a
count value G and an accumulated value H in association with
detection 6; and
[0062] FIG. 20 is a graph illustrating a relationship between a
count value G and a duty ratio in association with detection 6.
A LIST OF REFERENCE NUMERALS
[0063] 1: dewatering machine; 4: dewatering drum; 6: motor: 30:
control part; dg: duty ratio; dmax: maximum duty ratio; dn: duty
ratio; d0: reference duty ratio; dn_diff: corrected duty ratio; E:
first count value; G: count value; H: accumulated value; and Q:
washings.
DETAILED DESCRIPTION
[0064] Embodiments of the present disclosure are described below in
detail with reference to drawings.
[0065] FIG. 1 is a schematic longitudinal sectional right view
illustrating a dewatering machine 1 of an embodiment of the present
disclosure.
[0066] An up-down direction in FIG. 1 is called as an up-down
direction X of a dewatering machine 1, and a left-right direction
in FIG. 1 is called as a front-rear direction Y of the dewatering
machine 1. Firstly, the dewatering machine 1 is schematically
described. In the up-down direction X, an up direction is called as
an upper side X1, and a down direction is called as a lower side
X2. In the front-rear direction Y, a left direction in FIG. 1 is
called as a front direction Y1, and a right direction in FIG. 1 is
called as a rear direction Y2.
[0067] The dewatering machine 1 includes all apparatuses capable of
carrying out dewatering operation of washings Q. Therefore, the
dewatering machine 1 not only includes an apparatus having a
dewatering function, but also includes a washing machine having a
dewatering function and a washing and drying machine. The
dewatering machine 1 is described below by taking the washing
machine as an example.
[0068] The dewatering machine 1 includes a housing 2, an outer drum
3, a dewatering drum 4, a rotary wing 5, an electric motor 6, and a
transmission mechanism 7.
[0069] The housing 2 is made of, e.g., metal, and formed in a box
shape. An upper surface 2A of the housing 2 is formed obliquely
relative to the front-rear direction Y in a manner of extending to
the upper side X1 toward the rear direction Y2. An opening 8
connecting the inside and outside of the housing 2 is formed in the
upper surface 2A. A door 9 for opening and closing the opening 8 is
arranged on the upper surface 2A. An operation part 20 consisting
of a liquid crystal operation panel and the like is arranged in a
region toward the front direction Y1 than the opening 8 on the
upper surface 2A. A user can operate the operation part 20 to
select a dewatering condition freely, or instruct the dewatering
machine 1 to start or to stop.
[0070] The outer drum 3 is made of, e.g., resin, and formed in a
bottomed cylindrical shape. The outer drum 3 has a substantially
cylindrical circumferential wall 3A arranged along the up-down
direction X; a bottom wall 3B, configured to block a hollow part of
the circumferential wall 3A from the lower side X2; and an annular
wall 3C, which is annular and protrudes towards a circle center
side of the circumferential wall 3A while covering an edge at a
side of the upper side X1 of the circumferential wall 3A. An
outlet-inlet 10 communicated with the hollow part of the
circumferential wall 3A from the upper side X1 is formed inside the
annular wall 3C. The outlet-inlet 10 is arranged in opposite and
communicated state relative to the opening 8 of the housing 2 from
the lower side X2. A door 11 for opening and closing the
outlet-inlet 10 is arranged on the annual wall 3C. The bottom wall
3B is formed in a circular plate shape in a manner of substantially
extending horizontally. A through hole 3D penetrating through the
bottom wall 3B is formed in a position of the circle center of the
bottom wall 3B.
[0071] Water can be stored in the outer drum 3. A water supply
pipeline 12 connected with a faucet of tap water is connected with
the outer drum 3 from the upper side X1, and the tap water is
supplied into the outer drum 3 from the water supply pipeline 12. A
water supply valve 13 which can be opened and closed to start or
stop water supply is arranged in a midway of the water supply
pipeline 12. A drainage pipeline 14 is connected with the outer
drum 3 from the lower side X2, and the water in the outer drum 3 is
discharged outside the washing machine from the drainage pipeline
14. A drainage valve 15 which can be opened and closed to start or
stop drainage is arranged in a midway of the drainage pipeline
14.
[0072] The dewatering drum 4 is made of, e.g., metal, and is formed
in a bottomed cylindrical shape which is a circle smaller than the
outer drum 3, and can accommodate washings Q. The dewatering drum 4
has a substantially cylindrical circumferential wall 4A arranged
along the up-down direction X and a bottom wall 4B configured to
block a hollow part of the circumferential wall 4A from the lower
side X2.
[0073] An internal circumferential surface of the circumferential
wall 4A is an internal circumferential surface of the dewatering
drum 4. An upper end part of the internal circumferential surface
of the circumferential wall 4A is an outlet-inlet 21 for enabling
the hollow part of the circumferential wall 4A to expose to the
upper side X1 . The outlet-inlet 21 is arranged in opposite and
communicated state relative to the outlet-inlet 10 of the outer
drum 3 from the lower side X2. The outlet-inlet 10 and the
outlet-inlet 21 are opened and closed through the door 11 together.
A user of the dewatering machine 1 puts the washings Q in the
dewatering drum 4 and takes the washings Q out of the dewatering
drum 4 through the opened opening 8, the outlet-inlet 10 and the
outlet-inlet 21.
[0074] The dewatering drum 4 is coaxially accommodated in the outer
drum 3. The dewatering drum 4 accommodated in the outer drum 3 can
rotate around an axis 16 which forms a central axis and extends in
the up-down direction X. In addition, a plurality of through holes,
which are not shown, are formed in the circumferential wall 4A and
the bottom wall 4B of the dewatering drum 4, and the water in the
outer drum 3 can flow between the outer drum 3 and the dewatering
drum 4 through the through holes. Therefore, a water level in the
outer drum 3 is consistent with a water level in the dewatering
drum 4.
[0075] The bottom wall 4B of the dewatering drum 4 is spaced from
the bottom wall 3B of the outer tank 3 toward the upper side X1 and
is formed in a circular plate shape extending substantially
parallel. A through hole 4C penetrating through the bottom wall 4B
is formed in a position of a circle center of the bottom wall 4B
consistent with the axis 16. A tubular supporting shaft 17
surrounding the through hole 4C and stretching out to the lower
side X2 along the axis 16 is arranged on the bottom wall 4B. The
supporting shaft 17 is inserted into the through hole 3D of the
bottom wall 3B of the outer drum 3, and a lower end part of the
supporting shaft 17 is located closer to the lower side X2 relative
to the bottom wall 3B.
[0076] The rotary wing 5, i.e., an impeller, is formed in a discoid
shape by taking the axis 16 as a circle center, and is arranged
concentrically with the dewatering drum 4 along the bottom wall 4B
in the dewatering drum 4. A plurality of blades 5A radially
disposed are arranged on an upper surface of the rotary wing 5
toward the outlet-inlet 21 of the dewatering drum 4. A rotating
shaft 18 extending toward the lower side X2 from a circle center of
the rotary wing 5 along the axis 16 is arranged on the rotary wing
5. The rotating shaft 18 is inserted into a hollow part of the
supporting shaft 17, and a lower end part of the rotating shaft 18
is located closer to the lower side X2 relative to the bottom wall
3B of the outer drum 3.
[0077] In the present embodiment, the motor 6 is implemented
through a variable frequency motor. The motor 6 is arranged in the
lower side X2 of the outer drum 3 in the housing 2, and is provided
with an output shaft 19 rotating around the axis 16. A transmission
mechanism 7 is located between the lower end parts of both the
supporting shaft 17 and the rotating shaft 18, and an upper end
part of the output shaft 19. The transmission mechanism 7
selectively transmits a driving force outputted by the motor 6 from
the output shaft 19 to one or both of the supporting shaft 17 and
the rotating shaft 18. A widely known transmission mechanism can be
taken as the transmission mechanism 7.
[0078] The dewatering drum 4 and the rotary wing 5 rotate around
the axis 16 when the driving force from the motor 6 is transmitted
to the supporting shaft 17 and the rotating shaft 18. The washings
Q in the dewatering drum 4 are stirred through the rotating
dewatering drum 4 and the blades 5A of the rotary wing 5 during
washing and rinsing. In addition, the washings Q in the dewatering
drum 4 are dewatered through high-speed integrated rotation of the
dewatering drum 4 and the rotary wing 5 during dewatering after the
rinsing.
[0079] FIG. 2 is a block diagram illustrating an electric structure
of a dewatering machine 1.
[0080] Referring to FIG. 2, the dewatering machine 1 includes: a
load measuring unit, a drive control unit, an acquisition unit, a
timing determination unit, a determination unit, a stopping control
unit, an execution unit, a counting unit, a receiving unit, a
threshold value changing unit and a control part 30 as a
calculation unit. The control part 30 is disposed in the housing 2
(referring to FIG. 1) and includes, for example, a CPU 31; a memory
32 such as ROM or RAM; a timer 35; and a microcomputer as a counter
34.
[0081] The dewatering machine 1 further includes a water level
sensor 33 and a rotating speed reading apparatus 34. The water
level sensor 33, the rotating speed reading apparatus 34, the motor
6, the transmission mechanism 7, the water supply valve 13, the
drainage valve 15 and the operation part 20 are electrically
connected with the control part 30 respectively.
[0082] The water level sensor 33 is a sensor for detecting the
water levels of the outer drum 3 and of the dewatering drum 4, and
a detection result of the water level sensor 33 is inputted into
the control part 30 in real time.
[0083] The rotating speed reading apparatus 34 is an apparatus for
reading a rotating speed of the motor 6, and strictly speaking, for
reading a rotating speed of the output shaft 19 of the motor 6, and
consists of, e.g., a Hall integrated circuit (IC). The rotating
speed read by the rotating speed reading apparatus 34 is inputted
into the control part 30 in real time. The control part 30 controls
a duty ratio of a voltage applied to the motor 6 according to the
inputted rotating speed, and then, enables the motor 6 to rotate at
a desired rotating speed.
[0084] The control part 30 switches a transmission target of the
driving force of the motor 6 to one or both of the supporting shaft
17 and the rotating shaft 18 by controlling the transmission
mechanism 7. The control part 30 controls the opening and closing
of the water supply valve 13 and the drainage valve 15. As
mentioned above, when the user selects the dewatering condition and
the like of the washings Q by operating the operating part 20, the
control part 30 receives the selection.
[0085] Next, the dewatering operation of the dewatering machine 1
is described.
[0086] FIG. 3 is a time chart illustrating a state of a rotating
speed of a motor 6 in dewatering operation implemented by a
dewatering machine 1. In the time chart of FIG. 3, a horizontal
axis indicates elapsed time, and a vertical axis indicates a
rotating speed of the motor 6 (unit: rpm).
[0087] Referring to FIG. 3, in the dewatering operation, the
control part 30 measures the load of the washings Q in the
dewatering drum 4 when the dewatering drum 4 begins to rotate.
After the load is measured, the control part 30 enables the motor 6
to rotate at a constant speed of 120 rpm after the rotating speed
of the motor 6 is increased to 120 rpm. Then the control part 30
enables the motor 6 to rotate at a constant speed of 240 rpm after
the rotating speed of the motor 6 is increased from 120 rpm to 240
rpm. Then the control part 30 enables the motor 6 to rotate at a
constant speed of 800 rpm after the rotating speed of the motor 6
is increased from 240 rpm to 800 rpm. Through the constant rotation
of the motor 6 at 800 rpm, the washings Q in the dewatering drum 4
are formally dewatered. It shall be noted that during the
dewatering operation, when the rotating speed of the motor 6 is,
for example, comprised between 50 rpm and 60 rpm, the dewatering
drum 4 resonates horizontally, and when the rotating speed of the
motor 6 is, for example, comprised between 200 rpm and 220 rpm, the
dewatering drum 4 resonates longitudinally.
[0088] When the washings Q in the dewatering drum 4 are in a state
of being biased and arranged in the circumferential direction of
the dewatering drum 4, the washings Q are biased in the dewatering
drum 4. When the dewatering operation is carried out in such state,
the dewatering drum 4 performs eccentric rotation. Thus, the
dewatering drum 4 may swing widely, as such the dewatering machine
1 vibrate significantly and produce noise.
[0089] Therefore, the control part 30 detects whether the washings
Q in the dewatering drum 4 are biased during the dewatering
operation, and stops the motor 6 when the washings Q are detected
to be biased. In such detection, the control part 30 performs five
types of electric detections, i.e., detection 1, detection 2,
detection 3, detection 4 and detection 5.
[0090] The detections 1 to 4 are executed in a low-speed
eccentricity detection section, and the low-speed eccentricity
detection section includes an acceleration period where the
rotating speed of the motor 6 is increased from 120 rpm to 240 rpm
and a specified period after the motor 6 begins to accelerate to
240 rpm. The detection 5 is executed in a period where the rotating
speed of the motor 6 reaches 800 rpm from 240 rpm, i.e., a
high-speed eccentricity detection section.
[0091] FIG. 4 is a graph illustrating a relationship between the
weight and the load of the washings Q accommodated in the
dewatering drum 4, and the load is detected by the dewatering
machine 1 according to the weight of the washings Q. In the graph
of FIG. 4, the horizontal axis indicates the weight (unit: kg) of
the washings Q, and the longitudinal axis indicates a detection
value of the load.
[0092] Referring to FIG. 4, as described above, the control part 30
measures the load of the washings Q in the dewatering drum 4 when
the dewatering drum 4 begins to rotate. The control part 30 enables
the dewatering drum 4 to rotate at the specified rotating speed
when the dewatering drum 4 begins to rotate, and detects a value
obtained after accumulating the duty ratio of the voltage applied
to the motor 6 at this moment for a given times as the load. When
the weight of the washings Q is increased, since a high voltage
must be applied to the motor 6 to rotate the dewatering drum 4, the
load is increased along with the increase of the voltage. Thus, the
control part 30 electrically measures the load of the washings
Q.
[0093] FIG. 5A and FIG. 5B are flow charts illustrating outlines of
the detections 1 to 4.
[0094] Referring to FIG. 5A and FIG. 5B, when the dewatering
rotation of the dewatering drum 4 is started by starting the
dewatering operation (step S1), as described above, the control
part 30 measures the load of the washings Q in the dewatering drum
4 (step S2), and then the motor 6 rotates at a constant speed of
120 rpm (step S3).
[0095] Then, the control part 30 begins to accelerate the motor 6
to 240 rpm (step S4), and the detection 1 described above is
implemented during the acceleration of the motor 6 (step S5). In a
case where a result of the detection 1 is not "OK" (step S5: No),
that is, in a case where the control part 30 determines that the
washings Q are biased, the control part 30 stops the motor 6, stops
the rotation of the dewatering drum 4 (step SS6), and then
determines whether the dewatering operation can be restarted or not
(step S7).
[0096] Restart of the dewatering operation refers to rotating the
dewatering drum 4 to restart the dewatering operation immediately
after the control part 30 stops rotation of the dewatering drum 4
to suspend the dewatering operation. Detailed conditions will be
described below. Sometimes, the restart may also be conducted
according to the biased degree of the washings Q.
[0097] Before the restart, i.e., in a case where the restart has
not been implemented (step S7: Yes), the control part 30 executes
the restart (step S8). During the restarted dewatering operation,
the control part 30 shortens the duration of constant rotation at
120 rpm to be less than the duration of constant rotation at 120
rpm during the dewatering operation just stopped. In the case of
restart, since the washings Q are in a state of being attached to
an inner circumferential surface of the dewatering drum 4 to a
certain extent and removing most of the water, it is acceptable to
shorten the duration of constant rotation at 120 rpm. Thus, the
duration of the dewatering operation can be shortened. It shall be
noted that such reduction of duration can also be executed in
subsequent restarts.
[0098] When the restart cannot be performed (step S7: No), the
control part 30 executes an imbalance correction (step S9). During
the imbalance correction, after the drainage valve 15 is closed,
the control part 30 opens the water supply valve 13 and supplies
water into the dewatering drum 4 to reach a specified water level,
and the washings Q in the dewatering drum 4 are immersed in the
water so as to be easily scattered. In this state, the control part
30 rotates the dewatering drum 4 and the rotary wing 5, so that the
washings Q attached to the inner circumferential surface of the
dewatering drum 4 are dropped and stirred, thereby correcting the
bias of the washings Q in the dewatering drum 4.
[0099] On the other hand, in a case where the result of the
detection 1 is "OK" (step S5: Yes), that is, the control part 30
determines that the washings Q are not biased through the detection
1, the control part 30 continues to execute the above detection 2
(step S10) in the acceleration of the motor 6.
[0100] In a case where the result of the detection 2 is not "OK"
(step S10: No), that is, the control part 30 determines that the
washings Q are biased, the control part 30 stops the motor 6 and
the dewatering drum 4 so as to suspend the dewatering operation
(step S11). Then, the control part 30 confirms whether the
dewatering condition of the currently suspended dewatering
operation is a "wool fabric mode" or "independent dewatering
operation" (step S12).
[0101] The wool fabric mode is a dewatering condition for
dewatering the washings Q that are easy to absorb the water such as
wool fabrics. When the dewatering condition is the wool fabric mode
(step S12: Yes), and in a case where the currently suspended
dewatering operation is the condition that the restart has not been
implemented, i.e., before the restart (step S13: Yes), the control
part 30 executes the restart for shortening the duration of
constant rotation at 120 rpm (step S14).
[0102] In the case of the wool fabric mode, a great amount of water
oozed from the wool fabric and accumulated in the outer drum 3 may
obstruct the rotation of the dewatering drum 4. Thus, the control
part 30 may mistakenly determine that the result of the detection 2
is not "OK". Moreover, when the imbalance correction is performed
regardless of the mistaken determination and the wool fabric
absorbs a great amount of water again, the mistaken determination
may occur again in a subsequent detection 2. Therefore, in a case
where the result of the detection 2 is determines as not "OK" under
the wool fabric mode, the restart rather than the imbalance
correction is performed (step S14) as long as the restart is not
implemented (step S13: Yes). On the other hand, in the case of
being not before the restart, that is, as long as the currently
suspended dewatering operation is already restarted (step S13: No),
the control part 30 executes the imbalance correction (step
S15).
[0103] The independent dewatering operation refers to the
dewatering condition under which the rinsed washings Q are put into
the dewatering drum 4 and dewatered rather than the dewatering
operation executed subsequently to the washing operation and the
rinsing operation. In a case where the dewatering condition is the
independent dewatering operation (step S12: Yes) and before the
restart (step S13: Yes), the control part 30 executes the restart
(step S14).
[0104] In the case of the independent dewatering operation, when
the rinsed washings Q are immersed through the imbalance
correction, it is meaningless to prepare the rinsed washings Q in
advance. Therefore, in a case where the result of the detection 2
is determined not to be "OK" in the independent dewatering
operation, the restart rather than the imbalance correction is
performed as long as the restart has not been implemented. It shall
be noted that the control part 30 can also prompt a user to
redispose the washings Q in the dewatering drum 4 through the
display of the operation part 20 and the error report performed by
a buzzer. On the other hand, in the case of being not before the
restart (step S13: No), the control part 30 executes the imbalance
correction (step S15).
[0105] In another aspect, in a case where the dewatering condition
is neither the wool fabric mode nor the independent dewatering
operation (step S12: No), the control part 30 determines that the
currently suspended dewatering operation is before the restart, and
determines whether the dewatering operation can be restarted
subsequently or not (step S16). When the dewatering operation is
before the restart and can be restarted (step S16: Yes), the
control part 30 executes the restart for shortening the duration of
constant rotation at 120 rpm (step S17). When the condition of
being before the restart and capable of being restarted is not
satisfied (step S16: No), the control part 30 executes the
imbalance correction (step S18).
[0106] Moreover, in a case where the result of the detection 2 is
"OK" (step S10: Yes), that is, in a case where the control part 30
determines that the washings Q are not biased in the detection 2,
the control part 30 confirms if the value of the timer 35 is
greater than a set value per load (step 19). That is, in the step
S19, the control part 30 confirms whether the duration counted by
the timer 35 already reaches a set value corresponding to the load
of the washings Q in the dewatering drum 4. The set value is
described in detail below.
[0107] When the value of the timer 35 is greater than the set value
per load (step S19: Yes), and the motor 6 is in the state of
rotating at a constant speed of 240 rpm, the control part 30
executes the above detections 3 and 4 (step S20). In a case where
results of the detections 3 and 4 are not "OK" (step S20: No), that
is, the control part 30 determines that the washings Q are biased,
the control part 30 stops the motor 6 and the dewatering drum 4 so
as to suspend the dewatering operation (step S11), and executes the
corresponding processing in steps S12 to S18.
[0108] In another aspect, in a case where the results of the
detection 3 and detection 4 are "OK" (step S20: Yes), that is, in a
case where the control part 30 determines that the washings Q are
not biased in the detection 3 and detection 4, the control part 30
continues to rotate the motor 6 at a constant speed of 240 rpm so
as to continue the dewatering at 240 rpm (step S21).
[0109] Next, detections 1 to 4 are respectively described in
detail.
[0110] FIG. 6A and FIG. 6B are flow charts illustrating control
actions related to the detections 1 detection 2. Firstly, referring
to FIG. 6A and FIG. 6B, the detections 1 and 2 are described. The
detections 1 and 2 are detections of the bias of the washings Q by
utilizing the rotating speed of the motor 6.
[0111] In the above step S4, the control part 30 begins to
accelerate the motor 6 to 240 rpm and begins the detections 1 and
2. Firstly, the control part 30 trigger the timer 35 to time, and
measures a rotating speed V0 of the motor 6 at the beginning of the
acceleration through the rotating speed reading apparatus 34 (step
S31). The rotating speed V0 is about 120 rpm.
[0112] With respect to the value of the timer 35, i.e., the timing,
the detection time of the detections 1 and 2, i.e. the acceleration
time for the motor 6 to accelerate to 240 rpm varies depending on
the load. The reason is that the heavier the washings Q are, the
more time the motor 6 needs to reach the rotating speed of 240 rpm.
Therefore, the set value per load related to the acceleration time
of the motor 6 is obtained in advance through experiments and the
like, and stored in the memory 32.
[0113] Then, the control part 30 begins to count through the
counter 36 (step S32), and performs the counting once every 0.3
second by initializing the counter 36 once every 0.3 second (step
S33 and step S34).
[0114] The control part 30 measures the rotating speed Vn (n: count
value) of the motor 6 in each counting (step S35). In step S35, the
control part 30 calculates the difference Sn between the measured
rotating speed Vn and the rotating speed Vn-1 measured before the
Vn. Then, the control part 30 calculates the accumulated value U
based on an absolute value of the difference between a difference
Sn and a previous difference Sn-1 in the step S35.
[0115] Next, the control part 30 confirms whether the value of the
timer 35 is already greater than the set value per load, that is,
whether the measuring time of the timer 35 reaches the set value
corresponding to the load of the washings Q in the dewatering drum
4 (step S36). The step S36 is equivalent to the step S19 described
above (referring to FIG. 5A).
[0116] In a case where the value of the timer 35 is less than the
set value per load, that is, in a case where the timing of the
timer 35 does not reach the corresponding set value (step S36: No),
and when the load of the washings Q in the dewatering drum 4 is
less than a given amount (step S37: Yes), the control part 30
determines that whether the difference Sn just calculated falls
within the scope of the detection 1 (step S38). The given amount is
obtained in advance through the experiment and the like and stored
in the memory 32.
[0117] Specifically, the threshold value is preset for the
difference Sn and stored in the memory 32. FIG. 7 is a graph
illustrating the relationship between the rotating speed of the
motor 6 and the difference Sn in association with the detection 1.
In the graph of FIG. 7, the horizontal axis indicates the rotating
speed (unit: rpm), and the longitudinal axis indicates the
difference Sn (unit: rpm).
[0118] By referring to the range of the rotating speed indicated by
the dotted arrow in FIG. 7, in a case where the washings Q are
regarded not to be biased due to small eccentricity, because of the
stable acceleration of the dewatering drum 4, the deviation of the
difference Sn is small as shown by the solid line. However, in a
case where the washings Q are regarded to be biased due to large
eccentricity, because of the instable acceleration of the
dewatering drum 4, as shown by the dotted line, the deviation of
the difference Sn is large, and a minimum value of the difference
Sn is smaller than the threshold value. Therefore, returning to
FIG. 6A, when the difference Sn is smaller than or equal to the
threshold value, the control part 30 determines that the difference
Sn falls within the scope of the detection 1 (step S38: Yes). In
this way, in the detection 1, the instability degree of the
acceleration of the dewatering drum 4 indicating whether the
washings Q are biased is detected according to the difference
Sn.
[0119] When the control part 30 determines that the difference Sn
falls within the scope of the detection 1 (step S38: Yes), the
rotation of the motor 6 is stopped (step S6), and the corresponding
processing in the above steps S7 to S9 is executed (referring to
FIG. 5A). The processing of the step S31 to step 38 is included in
the above step S5 (referring to FIG. 5A).
[0120] When the control part 30 determines that the difference Sn
does not fall within the range of the detection 1 since the
difference Sn is greater than the threshold value (step S38: No),
the control part 30 determines whether the accumulated value U just
calculated falls within the scope of the detection 2 or not (step
S39).
[0121] In addition, when the load of the washings Q in the
dewatering drum 4 is greater than a given amount (step S37: No),
the control part 30 executes the determination performed by the
detection 2 in the step S39 rather than the determination performed
by the detection 1 in the step S38. The reason is that in a case
where the amount of the washings Q is greater than the given
amount, since a great amount of water is oozed out from the
washings Q or the bias of the washings Q is sharply changed due to
the sudden attachment of the washings Q to the inner
circumferential surface of the dewatering drum 4, it is possible
that the detection 1 cannot be performed stably. Therefore, in a
case where the amount of the washings Q is greater than the given
amount, the detection 1 is omitted.
[0122] In association with the determination about whether the
accumulated value U falls within the scope of the detection 2, the
threshold value is preset for the accumulated value U and stored in
the memory 32. FIG. 8 is a diagram illustrating the relationship
between the rotating speed of the motor 6 and the accumulated value
U in association with the detection 2. In the graph of FIG. 8, the
horizontal axis indicates the time (unit: sec), and the
longitudinal axis indicates the accumulated value U (unit: rpm). By
referring to FIG. 8, the threshold value is set as two threshold
values, i.e. the upper threshold value represented by cardinal
points and the upper threshold value represented by triangular
points. The upper threshold value is a value greater than the lower
threshold value.
[0123] In a case where the washings Q are not biased due to small
eccentricity, since the acceleration of the dewatering drum 4 is
stable, as shown by the solid line, the accumulated value U is
always lower than the lower threshold value at any time. However,
in a case where the washings Q are biased due to large
eccentricity, since the acceleration of the dewatering drum 4 is
instable, as shown by the dotted line, the accumulated value U is
greater than the lower threshold value at any time. When the the
washings Q are biased greatly, the accumulated value U is greater
than the upper threshold value. Therefore, returning to FIG. 6A,
when the accumulated value U is greater than or equal to the lower
threshold value, the control part 30 determines that the
accumulated value U falls within the scope of the detection 2 (step
S39: Yes). In this way, in the detection 2, the instability degree
of the acceleration of the dewatering drum 4 indicating whether the
washings Q are biased is detected according to the accumulated
value U.
[0124] When the control part 30 determines that the accumulated
value U falls within the scope of the detection 2 (step S39: Yes),
the rotation of the motor 6 is stopped (step S11), and the
corresponding processing in the above steps S12 to S18 is executed.
The treatment of the steps S31 to S37 and the step S39 is included
in the step S10 described above (referring to FIG. 5A).
[0125] In a case where the dewatering condition is neither the wool
fabric mode nor the independent dewatering operation (step S12:
No), in the step S16, the control part 30 determines whether the
bias of the washings Q is large enough to enable the accumulated
value U to be greater than the upper threshold value or whether the
currently suspended dewatering operation is already restarted or
not.
[0126] In a case where the accumulated value U is greater than the
upper threshold value or the dewatering operation is already
restarted (step S16: Yes), the control part 30 executes the
imbalance correction (Step S18). In a case where the accumulated
value U is lower than the upper threshold value and the dewatering
operation is not restarted (step S16: No), the control part 30
executes the restart (step S17). The determination about whether
the accumulated value U is greater than the upper threshold value
is equivalent to the determination about whether the restart can be
carried out in the step S16 of FIG. 5B, and the determination about
whether the restart is already carried out is equivalent to the
determination about whether it is before the restart in the step
S16 of FIG. 5B.
[0127] Thus, in the steps S16 to S18, the control part 30
determines whether the bias within the range of the detection 2 is
small enough to perform the restart subsequently or large enough to
perform the imbalance correct according to the determination abpit
whether the accumulated value U is greater than the upper threshold
value, and chooses to execute the restart and the imbalance
correction according to the bias.
[0128] Moreover, in a state in which both the detections 1 and 2
determine that the washings Q are not biased, when the value of the
timer 35 reaches the set value per load (step S36: Yes), the
control part 30 terminates the detections 1 and 2 (step S40). In
addition, in the step S40, the control part 30 acquires the duty
ratio of the voltage applied to the motor 6 at the time point when
the value of the timer 35 reaches the set value as the reference
duty ratio d0. At the time point when the value of the timer 35
reaches the set value and the processing in the step S40 is
executed, the motor 6 is in the acceleration state of accelerating
to 240 rpm.
[0129] As described above, the set value in the step S36 varies
depending on the load of the washings Q in the dewatering drum 4.
Therefore, the control part 30 determines the timing for acquiring
the reference duty ratio d0 in the step S40 according to the load
measured during the dewatering operation of the dewatering drum 4.
In other words, the control part 30 changes the timing for
terminating the detections 1 and 2 and starts the subsequent
detections 3 and 4 according to the load. Therefore, the detections
3 and 4 can be executed at the optimum timing corresponding to the
amount of the washings Q.
[0130] FIG. 9A and FIG. 9B are flow charts illustrating control
actions related to the detections 3 and 4. Referring to FIG. 9A and
FIG. 9B, the detections 3 and 4 are described. The detections 3 and
4 are detections of the bias of the washings Q by utilizing the
duty ratio of the voltage applied to the motor 6.
[0131] In the above step S40, the control part 30 acquires the
reference duty ratio d0 and starts the detections 3 and 4. When the
detections 3 and 4 start, the rotating speed of the motor 6 is in
the state of reaching 240 rpm, and the motor 6 rotates at a
constant speed of 240 rpm.
[0132] In association with the detections 3 and 4, a first count
value E and a second count value T exist and are stored in the
memory 32. When the detections 3 and 4 start, the control part 30
respectively resets the first count value E and the second count
value T to the initial value 0 (step S41).
[0133] Then, the control part 30 initiates the timer 35 to begin
the timing (step S42) and monitors whether the value of the timer
35 is greater than 8.1 seconds. The detections 3 and 4 are executed
within this specified period of 8.1 seconds after the reference
duty ratio d0 is acquired.
[0134] In addition, the control part 30 starts the counting through
the counter 36 in the step S42, and performs the counting once
every 0.3 second by initializing the timer 36 once every 0.3 second
(step S43 and step S44). In step S44, the control part 30 adds 1
(+1) to the second count value T at the timing when the counter 36
is initialized, i.e. the timing when the counting is performed at
every time.
[0135] The control part 30 acquires a duty ratio do (n: count
value) of the voltage applied to the motor 6 during counting at
every time of timing (step S45). That is, within this specified
period of 8.1 seconds, the control part 30 acquires a duty ratio dn
once at the specified timing of every 0.3 second.
[0136] In addition, in the step S45, the control part 30 performs
the operation for the corrected duty ratio dn diff at the timing of
every 0.3 second on the basis of the following formula (1) and
formula (2). The corrected duty ratio dn_diff is a value obtained
by correcting the duty ratio dn acquired at the same timing, so
that the detection in the detection 4 can be accurately executed.
In addition, A and B in the formula (1) and formula (2) are
constants obtained through the experiment and the like.
dn_diff=A.times.dn-dn_x Formula (1)
dn_x=(A.times.d0)-(B.times.T) Formula (2)
[0137] Next, when the acquired duty ratio dn is greater than or
equal to the duty ratio dn-1 acquired last time (step S46: Yes),
the control pat 30 adds 1 (+1) to the first count value E (step
S47). Furthermore, in the detection 3, the duty ratio dn originally
acquired by the control part 30 is the above reference duty ratio
d0. In another aspect, when the acquired duty ratio dn is less than
the duty ratio dn-1 acquired at the last timing (step S46: No), the
control part 30 resets the first count value E to the initial value
0 (zero) (step S48).
[0138] Then, the control part 30 confirms whether the value of the
timer 35 is less than 8.1 seconds, i.e., whether the measuring time
of the timer 35 is greater than 8.1 seconds (step S49).
[0139] In a case where the value of the timer 35 is less than 8.1
seconds (step S49: Yes), when the load of the washings Q in the
dewatering drum 4 is greater than a given amount (step S50: Yes),
the control part 30 determines whether the latest first count value
E falls within the scope of the detection 3 (step S51). The given
amount is obtained in advance through the experiment and the like
and stored in the memory 32.
[0140] Specifically, the threshold is preset for the first count
value E and stored in the memory 32. FIG. 10 is a graph
illustrating the relationship between the time and the first count
value E in association with the detection 3. In the graph of FIG.
10, the horizontal axis indicates the time (unit: sec), and the
longitudinal axis indicates the first count value E. Referring to
FIG. 10, the threshold is provided with two values, i.e. a lower
threshold value represented by a single-point line and an upper
threshold value represented by a double-point line. Both the upper
value and the lower value are unrelated to the elapsed time and are
fixed values. The upper value is greater than the lower value.
[0141] In a case where the washings Q are not biased due to small
eccentricity, even if the voltage is low, the motor 6 can also
rotate at a constant speed of 240 rpm, so that the duty ratio dn is
gradually decreased. Thus, as shown by the solid line, the first
count value E is stabilized in proximity to the initial value
0.
[0142] However, in a case where the washings Q are biased due to
large eccentricity, since the high voltage is needed to maintain
the rotating speed of the motor 6 at 240 rpm, the duty ratio dn is
not decreased. Thus, the first count value E is increased rather
than returned to the initial value, and as shown by the dotted
line, the first count value E is greater than the lower threshold
value at any timing. When the washings Q are biased greatly, the
first count value E may also be greater than the upper threshold
value.
[0143] Therefore, returning to FIG. 9A, when the latest first count
value E is greater than or equal to the lower threshold value, the
control part 30 determines that the first count value E falls
within the scope of the detection 3 (step S51: Yes). That is, when
the first count value E within the above specified period of 8.1
seconds is greater than or equal to the specified threshold, the
control part 30 determines that the washings Q in the dewatering
drum 4 are biased.
[0144] As long as the change between adjacent duty ratios dn
obtained at timing is always monitored like in the detection 3,
even if the reference duty ratio d0, i.e., the change between the
duty ratio dn and the initial duty ratio dn, acquired at the
beginning of the detection is small, the accurate detection for
controlling the change of the duty ratio dn during the detection in
real time can also be performed. Thus, the accuracy for detecting
whether the washings Q are biased can be improved.
[0145] Then, when the control part 30 determines that the first
count value E does not fall within the range of the detection 3
since the first count value E is less than the lower threshold
value (step S51: No), the control part 30 determines whether the
corrected duty ratio dn_diffjust obtained falls within the scope of
the detection 4 (step S52).
[0146] In addition, when the load of the washings Q in the
dewatering drum 4 is less than a given amount (step S50: No), the
control part 30 executes the determination performed by the
detection 4 in the step S52 rather than the determination performed
by the detection 3 in the step S51. The reason is that when the
detection 3 is executed in a case where the amount of the washings
Q is less than the given amount, the first count value E is
instable since the duty ratio dn is converged at an early stage, so
it is possible that the detection 3 cannot be executed stably.
Therefore, in a case where the amount of the washings Q is less
than the given amount, the detection 3 is omitted.
[0147] Determination about whether the corrected duty ratio dn_diff
falls within the scope of the detection 4 is that the threshold is
preset for the corrected duty ratio dn_diff and is stored in the
memory 32. FIG. 11 is a graph illustrating a relationship between
the time and the corrected duty ratio dn_diff in association with
the detection 4. In the graph of FIG. 11, the horizontal axis
represents time (unit: second) and the vertical axis represents the
corrected duty ratio dn_diff. By referring to FIG. 11, two
threshold values including a lower threshold value represented by a
single-dot dash line and an upper threshold value represented by a
double-dot dash line are set for the threshold. The upper threshold
value and the lower threshold value gradually increase with elapsed
time, respectively. The upper threshold value is greater than the
lower threshold value.
[0148] In a case where the washings Q are not biased due to small
eccentricity, since the motor 6 can also rotate at the constant
speed of 240 rpm even if the voltage is low, the corrected duty
ratio dn_diff is smaller than the lower threshold value and
gradually decreases as shown by a solid line.
[0149] However, in a case where the washings Q are biased due to
large eccentricity, a high voltage is required to maintain the
rotating speed of the motor 6 at 240 rpm. Therefore, the corrected
duty ratio dn_diff does not decrease, but exceeds the lower
threshold value as shown by a dotted line. When the washings Q are
biased greatly, the corrected duty ratio dn_diff may exceed the
upper threshold value. Therefore, returning to FIG. 9A, when the
corrected duty ratio dn_diff is greater than the lower threshold
value, the control part 30 determines that the corrected duty ratio
dn_diff falls within the scope of the detection 4 (step S52:
Yes).
[0150] It shall be noted that the corrected duty ratio dn_diff
obtained by the above formulas (1) and (2) is a value set when the
duty ratio dn is equal to or greater than the reference duty ratio
d0 and is increased over time. Therefore, the corrected duty ratio
dn_diff does not fall within the threshold values only when the
duty ratio dn decreases normally relative to the reference duty
ratio d0.
[0151] As mentioned above, the first count value E for the
detection 3 and the corrected duty ratio dn_diff for the detection
4 refer to indexes of change between the duty ratio dn of the
voltage applied to the motor 6 and the reference duty ratio d0
within the specified period of 8.1 seconds for maintaining the
rotating speed of 240 rpm. The control part 30 determines whether
the washings Q in the dewatering drum 4 are biased based on such
indexes in the detections 3 and 4.
[0152] In addition, since the first count value E for the detection
3 and the corrected duty ratio dn_diff for the detection 4 are
obtained based on the reference duty ratio d0, the reference duty
ratio d0 is an important factor which affects accuracy for
detecting whether the washings Q are biased. In the dewatering
machine 1, as described above, the control part 30 measures the
load of the washings Q in the dewatering drum 4 (step S2 in FIG.
5A) when the dewatering drum 4 starts to rotate, and determines the
timing for acquiring the reference duty ratio d0 according to the
measured load (step S36 in FIG. 6A). Thus, since the reference duty
ratio d0 is acquired at appropriate timing in consideration of the
influence of the load, whether the washings Q are biased can be
accurately detected in the detections 3 and 4 according to the
reference duty ratio d0. As a result, the accuracy for detecting
whether the washings Q are biased can be improved.
[0153] Moreover, when the control part 30 determines that the first
count value E falls within the scope of the detection 3 (step S51:
Yes) or determines that the corrected duty ratio dn_diff falls
within the scope of the detection 4 (step S52: Yes), the rotation
of the motor 6 is stopped (the step S11) and the corresponding
processing in steps S12-S18 is performed. The processing in steps
S40-S52 is included in the step S20 (referring to FIG. 5A).
[0154] Steps S16A and S16B in FIG. 9B are included in the above
step S16 (referring to FIG. 5B). Specifically, the determination in
the step S16A is equivalent to the determination of whether it is
before the restart in the step S16 in FIG. 5B; and the
determination in the step S16B is equivalent to the determination
of whether the restart is performed in the step S16 in FIG. 5B.
[0155] When the dewatering condition is neither a woolen fabric
mode nor a single-dewatering operation (step S12: No), the control
part 30 determines whether the currently suspended dewatering
operation is before a restart in the step S16A. When the currently
suspended dewatering operation is determined to be before the
restart (step S16A: Yes), the control part 30 determines whether
the bias of the washings Q is as low as an extent that both the
first count value E and the corrected duty ratio dn_diff are
smaller than respective upper threshold values.
[0156] When the currently suspended dewatering operation is before
the restart (step S16A: Yes) and the first count value E and the
corrected duty ratio dn_diff are smaller than the respective upper
threshold values (step S16B: Yes), the control part 30 executes the
restart (step S17).
[0157] When the currently suspended dewatering operation is not
before the restart, i.e., the restart is completed (step S16A: No),
the control part 30 executes imbalance correction (step S18). In
addition, even if the currently suspended dewatering operation is
before the restart (step S16A: Yes), in a case where at least one
of the first count value E and the corrected duty ratio dn_diff is
greater than the respective upper threshold value (step S16B: No),
the control part 30 executes imbalance correction (step S18).
[0158] In this way, in a case where the rotation of the dewatering
drum 4 is stopped in the step S11, the controller 30 determines the
bias falling within the scopes of the detection 3 and the detection
4 is small enough to continue to restart or is large enough to
require imbalance correction according to the first count value E
and the corrected duty ratio dn_diff in steps S16B to S18.
[0159] In other words, the control part 30 executes the restart or
the imbalance correction according to the first count value E and
the corrected duty ratio dn_diff, i.e., according to whether the
values are greater than or equal to the respective upper threshold
values. Therefore, when the washings Q are determined to be biased,
the imbalance correction is not necessarily executed. Thus, when
the first count value E and the corrected duty ratio dn_diff are
values representing small bias of the washings Q, the time for the
dewatering operation can be shortened by executing the restart
immediately.
[0160] Moreover, when the washings Q are determined to be not
biased in both the detections 3 and 4, and the value of the timer
35 passes 8.1 seconds (step S49: No), the control part 30
terminates the detections 3 and 4 (step S53).
[0161] Next, the detection 5 is described in detail. Specifically,
the detection 5 is divided into detection 5-1 and detection 5-2.
FIG. 12 is a flow chart illustrating outlines of the detection 5-1
and the detection 5-2. In detection 5-1 and the detection 5-2,
whether the washings Q are biased is detected by utilizing the duty
ratio.
[0162] Referring to FIG. 12, after the detections 3 and 4 are
completed, the motor 6 continues to rotate at the constant speed of
240 rpm for a specified duration. With expiration of the specified
time, the control part 30 accelerates the motor 6 from 240 rpm to
the target rotating speed of 800 rpm (step S60).
[0163] When the rotating speed of the motor 6 reaches 300 rpm in a
state where the motor 6 is accelerated, the control part 30 takes
the duty ratio of the voltage applied to the motor 6 at the time
point as an .alpha. value (step S61). 300 rpm is the rotating speed
at which the dewatering drum 4 does not store water and is least
affected by the eccentricity of the dewatering drum 4. Therefore,
the .alpha. value at 300 rpm is the duty ratio in a state of being
least affected by the eccentricity of the dewatering drum 4 and
only affected by the load of the washings Q.
[0164] Then, the control part 30 performs the above detection 5-1
when the motor 6 continues to accelerate and the rotating speed is
increased from 600 rpm to 729 rpm (step S62). When the result of
the detection 6-1 is not "OK" (step S62: No), i.e., the control
part 30 determines that the washings Q are biased, the control part
30 stops the motor 6 and stops the rotation of the dewatering drum
4 (step S63). In this way, after the dewatering operation is
suspended, the control part 30 determines whether the dewatering
operation is before the restart, i.e., determines whether the
currently suspended dewatering operation has already been restarted
(step S64).
[0165] When the dewatering operation is before the restart (step
S64: Yes), the control part 30 executes the restart (step S65).
When the dewatering operation is not before the restart (step S64:
No), the control part 30 executes the imbalance correction (step
S66).
[0166] On the other hand, in a case where the result of the
detection 5-1 is "OK" (step S62: Yes), i.e., the control part 30
determines that the washings Q are not biased in the detection 5-1,
the control part 30 continues to perform the detection 5-2 in a
state that the motor 6 continues accelerating from 730 rpm (step
S67).
[0167] In a case where the result of the detection 5-2 is "OK"
(step S67: Yes), i.e., the control part 30 determines that the
washings Q are not biased in the detection 5-2, the control part 30
continues dewatering the washings Q by rotating the motor 6 at the
constant target rotating speed after accelerating the motor 6 to
the target rotating speed (800 rpm) (step S68).
[0168] On the other hand, when the result of the detection 5-2 is
not "OK" (step S67: No), i.e., in a case where the control part 30
determines that the washings Q are biased, the control part 30
continues to dewater the washings Q by rotating the motor 6 at a
constant rotating speed below the target rotating speed (step
S69).
[0169] Next, the detection 5-1 and the detection 5-2 are
respectively described in detail.
[0170] FIG. 13 is a flow chart illustrating control actions related
to the detection 5-1.
[0171] Referring to FIG. 13, the control part 30 starts the
detection 5-1 as the rotating speed of the motor 6 reaches 600 rpm
in a state of continuing accelerating the motor 6 after the step
S61 (referring to FIG. 12) (step S70).
[0172] Then, the control part 30 starts to count through the
counter 36 (step S71). The counter 36 is initialized once every 0.3
second so as to count once every 0.3 second (steps S72 and
S73).
[0173] The control part 30 acquires a rotating speed of the motor 6
during each counting and a duty ratio dn (n: a count value) of
voltage applied to the motor 6 during the counting (step S74).
Namely, the control part 30 acquires the rotating speed and the
duty ratio dn of the motor 6 at each specified moment within a
period where the rotating speed of the motor 6 reaches 800 rpm from
240 rpm.
[0174] In addition, the control part 30 calculates a correction
value Bn obtained by correcting the duty ratio dn with the a value
according to a following formula (3) in step S74. It shall be noted
that X and Y in the formula (3) are constants derived from
experiments and the like. Different from simple ratio calculation,
a weight in the formula (3) is changed, so that the correction
value Bn obtained by correcting the duty ratio dn can execute the
detection 5-1 with good accuracy.
Bn=dn-(.alpha..times.X+Y) Formula (3)
[0175] In addition, the control part 30 calculates a moving
accumulated value Cn (n: count value) of the correction value Bn in
step S74. The moving accumulated value Cn (n: count value) is a sum
of 5 consecutive correction values Bn in a counting sequence.
Moreover, for a certain moving accumulated value Cn and a previous
moving accumulated value Cn-1, the 4 correction values Bn on the
rear side of the 5 correction values Bn forming the moving
accumulated value Cn-1 are same with the 4 correction values Bn on
the front side of the 5 correction values Bn forming the moving
accumulated value Cn. It shall be noted that the quantity of the
correction values Bn summed for forming the moving accumulated
value Cn is not limited to 5.
[0176] Furthermore, the control part 30 calculates a threshold of
the moving accumulated value Cn (step S75) according to a following
formula (4).
The threshold=(rotating speed) .times.a+b Formula (4)
[0177] The a and b in the formula (4) are constants derived from
experiments and the like and stored in the memory 32. In addition,
constants a and b vary depending on the current rotating speed of
the motor 6 and a selected dewatering condition. Thus, the
threshold herein has multiple values at the same rotating speed. It
shall be noted that, it can be known from the formula (4) that the
threshold is not influenced by the a value.
[0178] Then, the control part 30 confirms whether the current
rotating speed of the motor 6 is less than 730 rpm or not (step
S76).
[0179] In a case where the current rotating speed of the motor 6 is
less than 730 rpm (step S76: "Yes"), the control part 30 determines
whether a last moving accumulated value Cn falls within the scope
of the detection 5-1 or not (step S77).
[0180] FIG. 14 is a graph illustrating a relationship between the
rotating speed and the moving accumulated value Cn in association
with the detections 5-1 and 5-2. In the graph of FIG. 14, a
horizontal axis represents the rotating speed (unit: rpm), and a
longitudinal axis represents the moving accumulated value Cn.
Referring to FIG. 14, for the threshold calculated in step S75, two
threshold values including a first threshold value represented by a
single-dot dash line and a second threshold value represented by a
double-dot dashed line are set according to, for example, different
dewatering conditions. The first threshold value is higher than the
second threshold value.
[0181] Following dewatering conditions exist: a dewatering
condition in which dewatering operation is carried out after water
is stored in the dewatering drum 4 and washings are rinsed in
"ordinary rinsing" mode, a dewatering condition of "water-splashing
and dewatering" in which dewatering is performed and water is
splashed to the washings Q when water is drained, a dewatering
condition of "restart", etc. The use operates the operation part 20
to make a selection from these dewatering conditions, and selection
is received by the control part 30. In the dewatering after washing
and ordinary rinsing, the acceleration of the motor 6 needs a force
since the washings Q contain a great quantity of water; while under
the condition of "water-splashing and dewatering" and "restart",
the acceleration of the motor 6 may need a very tiny force since
the washings are in a state of removing water to some extent.
[0182] In the dewatering operation after washing and ordinary
rinsing, the control part 30 uses the first threshold value higher
than the second threshold value since the detection can hardly be
implemented using the second threshold value. On the other hand, in
the dewatering after water splashing, dewatering and the restart,
the control part 30 uses the second threshold value lower than the
first threshold value since the detection is not accurate if the
control part 30 uses the first threshold value. Thus, under either
the condition that the washings Q contain a great quantity of water
or the condition that the water of the washings Q is removed to
some extent, the detection 5-1 is executed by using the threshold
value adapted with respective conditions.
[0183] In addition, based on the objective same as the
differentiation of such dewatering conditions, under the condition
of large load of the washings Q in the dewatering drum 4, the
control part 30 uses the first threshold value higher than the
second threshold value since the detection can hardly be
implemented using the second threshold value in the detection 5-1.
In addition, under the condition of small load of the washings Q in
the dewatering drum 4, the control part 30 uses the second
threshold value lower than the first threshold value since the
detection is not accurate if the control part 30 uses the first
threshold value in the detection 5-1. Thus, the detection 5-1 is
executed by using the threshold value adapted with different loads
of the washings Q respectively.
[0184] It shall be noted that, although the two threshold values
including the first threshold value and the second threshold value
are illustrated in FIG. 14, more than 3 threshold values may also
be set according to various dewatering conditions and loads.
[0185] Moreover, compared with the condition that the washings Q
are not biased due to smaller eccentricity (referring to a solid
line), the moving accumulated value Cn at each rotating speed is
increased under the condition that the washings Q are biased due to
large eccentricity (referring to the dotted lines in FIG. 14). If
the washings Q are greatly biased, the moving accumulated value Cn
is larger than the set threshold values, i.e., a corresponding one
of the first threshold value and the second threshold value.
[0186] Thus, returning to FIG. 13, when the newest moving
accumulated value Cn is above the set threshold value, the control
part 30 determines that the moving accumulated value Cn falls
within the scope of the detection 5-1 (step S77: "Yes").
[0187] When the control part 30 determines that the moving
accumulated value Cn falls within the scope of the detection 5-1
(step S77: "Yes"), the rotation of the motor 6 is stopped (the
above step S63) and the corresponding processing in step S64-step
S66 is executed. The processing in step S71-step S77 is included in
the step S62 (referring to FIG. 12).
[0188] Then, in a state that washings Q are determined to be not
biased in the detection 5-1, when the rotating speed of the motor 6
reaches 730 rpm (step S76: "No"), the control part 30 ends the
detection 5-1, and then starts the detection 5-2 (step S78).
[0189] FIG. 15 is a flow chart illustrating control actions related
to detection 5-2.
[0190] Referring to FIG. 15, in a state that the motor 6 continues
accelerating, the control part 30 starts to carry out the detection
5-2 (step S78 above) as the rotating speed of the motor 6 reaches
730 rpm.
[0191] Then, the control part 30 starts to count through the
counter 36 (step S79) and initializes the counter 36 per 0.3 s so
as to carry out counting per 0.3 s (step S80 and step S81).
[0192] Like step S74 in the detection 5-1, the control part 30 may
acquire the rotating speed of the motor 6 during each counting and
the duty ratio dn of the voltage applied to the motor 6 during the
counting, and calculate the correction value Bn and the moving
accumulated value Cn (step S82).
[0193] Then, the control part 30 calculates the threshold for the
moving accumulated value Cn according to the formula (4) (step
S83). The constants a and b forming the formula (4) are same as
those in detection 5-1, and may have different values due to the
current rotating speed of the motor 6 and the selected dewatering
condition. Thus, the threshold herein includes multiple values at
the same rotating speed, e.g., the first threshold value and the
second threshold value.
[0194] Then, the control part 30 confirms whether the current
rotating speed of the motor 6 reaches the target rotating speed
(800 rpm) (step S84).
[0195] Under the condition that the current rotating speed of the
motor 6 is less than the target rotating speed (step S84: "Yes"),
like in the detection 5-1 (step S77), the control part 30
determines whether the newest moving accumulated value Cn falls
within the scope of the detection 5-2 (step S85).
[0196] Specifically, referring to FIG. 14, in a case where the
washings Q are biased due to large eccentricity (referring to the
dotted lines in FIG. 14), compared with the condition that the
washings Q are not biased due to small eccentricity (referring to
the solid line), the moving accumulated value Cn at each rotating
speed is increased. When the washings Q are greatly biased, the
moving accumulated value Cn is larger than the set threshold value,
i.e., a corresponding one of the first threshold values and the
second threshold values.
[0197] Thus, returning to FIG. 15, when the newest moving
accumulated value Cn is above the set second threshold value, the
control part 30 determines that the moving accumulated value Cn
falls within the scope of the detection 5-2 (step S85: "Yes").
[0198] When the control part 30 determines that the moving
accumulated value Cn falls within the scope of the detection 5-2
(step S85: "Yes"), the rotating speed L of the motor 6 is acquired
at a determined time point, i.e., in the detection 5-2 (step
S86).
[0199] Then, the control part 30 rotates the motor 6 constantly at
the acquired rotating speed L, strictly speaking, a rotating speed
obtained by rounding away the single digit of the rotating speed L
from zero, so that the washings Q are continuously dewatered (step
S69 above). At this moment, the control part 30 prolongs dewatering
time at the rotating speed L so as to obtain a same dewatering
effect as that of dewatering at an original target rotating
speed.
[0200] Then, in a state that the washings Q are determined to be
not biased in the detection 5-2, when the rotating speed of the
motor 6 reaches the target rotating speed (step S84: "No"), the
control part 30 terminates the detection 5-2 and rotates the motor
6 constantly at the target rotating speed so as to continue
dewatering the washings Q (step S68 above).
[0201] As described above, in the detections 5-1 and 5-2, the
control part 30 changes the threshold according to the dewatering
conditions received by the operation part 20 (steps S75 and S83).
Moreover, when the acquired duty ratio dn, strictly, the moving
accumulated value Cn calculated based on the acquired duty ratio dn
is greater than a changed specified threshold value, the control
part 30 determines whether the washings Q are biased in the
dewatering drum 4. In other words, since whether the washings Q are
biased can be detected using the threshold suitable for each
dewatering condition during the dewatering operation in each
dewatering condition, the accuracy for detecting whether the
washings Q are biased can be improved.
[0202] The present disclosure is not limited to the above-described
embodiments; and various changes can be made within the scope of
claims.
[0203] For example, during the dewatering operation, particularly
when the rotating speed of the motor 6 is lower than 600 rpm, the
water may not be drained smoothly as the foam blocks the drainage
pipeline 14. Therefore, the control part 30 can control the
detection of the foam in the drainage pipeline 14 in parallel with
the related control in the detections 1 to 5.
[0204] FIG. 16 is a flow chart illustrating a control action of
detecting the foam in the dewatering operation.
[0205] Referring to FIG. 16, the control part 30 starts the
dewatering of the dewatering drum 4 by starting the dewatering
operation (the step S1). Thus, the rotating speed of the motor 6 is
increased as described above (referring to FIG. 3).
[0206] The control part 30 acquires the rotating speed of the motor
6 once at every specified timing in the dewatering operation and
the duty ratio of the voltage applied to the motor 6, i.e., the
duty ratio of applied voltage (step S91).
[0207] When the rotating speed of the motor 6 is lower than 600 rpm
(step S92: Yes), the control part 30 calculates a voltage limit
value V_limit (step S93). The voltage limit value V_limit is the
duty ratio of the maximum voltage applied to the motor 6 at each
rotating speed and is calculated by substituting the rotating speed
into the specified formula.
[0208] Moreover, the control part 30 detects the foam in the
drainage pipeline 14 by determining whether the duty ratio of the
applied voltage acquired in the step S91 is greater than the
voltage limit value V_limit at every timing (step S94).
[0209] Specifically, since the water is accumulates at the bottom
of the dewatering drum 4 and prevents the dewatering drum 4 from
rotating when the foam blocks the drainage pipeline 14 and the
water cannot be drained, in order to rotate the dewatering drum 4,
a voltage equivalent to the duty ratio of the applied voltage above
the voltage limit value V_limit must be applied to the motor 6.
Therefore, when the duty ratio of the applied voltage is greater
than the voltage limit value V_limit, the control part 30
determines that it is in such a state that the foam blocks the
drainage pipeline 14 (step S94: Yes). On the other hand, when the
duty ratio of the applied voltage is smaller than the voltage limit
value V_limit, the control part 30 determines that it is in such a
state that the foam does not block the drainage pipeline 14 (step
S94: No).
[0210] When the control part 30 determines that the foam blocks the
drainage pipeline 14 (step S94: Yes), whether it is before the
restart is determined, i.e., whether the currently suspended
dewatering operation is restarted (step S95).
[0211] When it is before the restart (step S95: Yes), the control
part 30 executes the restart (step S96). When it is not before the
restart (step S95: No), the control part 30 executes the imbalance
correction (step S97). Regardless of executing the restart or the
imbalance correction, the dewatering operation may be restarted
after a temporary suspension. Therefore, during the restart of the
dewatering operation, the foam in the drainage pipeline 14 may
disappear naturally.
[0212] On the other hand, when the rotating speed of the motor 6 is
greater than 600 rpm (step S92: No), the control part 30 terminates
the processing of detecting the foam (step S98).
[0213] In addition, the control of FIG. 16 not only is used for
detecting the foam, but also can be used for detecting a phenomenon
of "stagnant water" that the water in the outer drum 3 cannot reach
the drainage pipeline 14 due to vibration and the like.
[0214] In addition, in a low-speed eccentricity detection section
(referring to FIG. 3) of the dewatering operation, the detections 1
to 4 are executed in order to electrically detect whether the
washings Q in the dewatering drum 4 are biased. However, the
detection 6 described below can also be executed instead of the
detections 1 to 4, or the detection 6 can also be executed in
parallel with the detections 1 to 4.
[0215] FIG. 17 is a time chart illustrating a state of the rotating
speed of the motor 6 during the dewatering operation in association
with the detection 6, and specifically, a chart from which a
portion equivalent to the low-speed eccentricity detection section
in FIG. 3 is deleted. Therefore, in the time chart of FIG. 17, the
horizontal axis represents the elapsed time and the vertical axis
represents the rotating speed (unit: rpm) of the motor 6, as in
FIG. 3. It shall be noted that, in FIG. 17, the state of the duty
ratio of the voltage applied to the motor 6 by the control part 30
is represented by the dotted line, besides the state of the
rotating speed of the motor 6 is represented by the solid line.
[0216] Referring to FIG. 17, the control part 30 controls the duty
ratio in such a manner that the maximum value of the duty ratio is
generated during an acceleration state of accelerating the motor 6
from 120 rpm to 240 rpm in the low-speed eccentricity detection
section. At this time, an accelerated speed of the motor 6 is
controlled to be always fixed. The maximum value of the duty ratio
generated during the acceleration state of the motor 6 is called
the maximum duty ratio dmax below. Specifically, the control part
30 controls the duty ratio in such a manner that the maximum duty
ratio dmax is generated at a rotating speed (for example, 180 rpm)
slightly lower than the rotating speed (200 rpm to 220 rpm) at
which the dewatering drum 4 resonates, and specifically,
longitudinally resonates.
[0217] Such control of the duty ratio can be executed commonly
regardless of the magnitude of the load of the washings Q in the
dewatering drum 4. In addition, in order to realize the control, a
gain and the like representing the difference between the target
rotating speed of the motor 6 and a current actual rotating speed
and representing responsiveness of the change of the rotating speed
relative to the duty ratio are preset in the control part 30. It
shall be noted that the rotating speed at which the longitudinal
resonance occurs is called longitudinal resonance rotating speed
below.
[0218] When the control part 30 starts to accelerate the motor 6
from 120 rpm, the duty ratio gradually increases as shown by the
dotted line in FIG. 17. Then, the maximum duty ratio dmax is
generated when the rotating speed of the motor 6 reaches 180 rpm.
When the washings Q are not biased in the dewatering drum 4, since
the motor 6 can be accelerated to 240 rpm even if the duty ratio is
relatively small after the maximum duty ratio dmax is generated,
the duty ratio gradually decreases as shown by the dotted line.
[0219] However, when the washings Q are biased in the dewatering
drum 4, the vibration is increased as the rotating speed of the
motor 6 approaches the longitudinal resonance rotating speed.
Therefore, since the duty ratio must be increased to 240 rpm, the
duty ratio dmax needs to be increased even after the maximum duty
ratio dmax is generated, and the duty ratio after the maximum duty
ratio dmax is generated can hardly decrease. Therefore, after the
maximum duty ratio dmax is generated, the duty ratio may be
maintained at a value slightly lower than the maximum duty ratio
dmax without decrease as shown by a one-dot lock line in FIG. 17,
or may be increased after temporarily falling below the maximum
duty ratio dmax as shown by the double-dot dash line in FIG. 17. In
the detection 6, whether the washings Q in the dewatering drum 4
are biased is electrically detected by monitoring a relative change
between the duty ratio after the maximum duty ratio dmax is
generated and the maximum duty ratio dmax.
[0220] FIG. 18 is a flow chart illustrating control actions related
to the detection 6. Referring to FIG. 8, the detection 6 is
described.
[0221] In the step S4, the control part 30 starts to accelerate the
motor 6 from 120 rpm to 240 rpm. Then, since the duty ratio has the
maximum value when the rotating speed of the motor 6 reaches, for
example, 180 rpm in the acceleration state of accelerating the
motor 6 to 240 rpm, the control part 30 takes the maximum value as
the maximum duty ratio dmax (step S101).
[0222] In association with the detection 6, a count value G and an
accumulated value H exist and are stored in the memory 32. When
acquiring the maximum duty ratio dmax, the control part 30 resets
the count value G and the accumulated value H to an initial value 0
(step S101).
[0223] Then, after the maximum duty ratio dmax is acquired, when
the rotating speed of the motor 6 reaches the rotating speed (for
example, 200 rpm) immediately before the longitudinal resonance
(step S102: Yes), the control part 30 starts the timer 35 to start
the timing and starts to count by the counter 36 (step S103). As a
result, the detection 6 is started. The control part 30 initializes
the counter 36 once every specified time (for example, 0.1 second)
to count once every 0.1 second (steps S104 and S105) by referring
to the value of the timer 35. The control part 30 adds one (+1) to
the count value G once at timing of initializing the counter 36
every time in step S105, i.e., at timing of counting every
time.
[0224] The control part 30 acquires the duty ratio dg (g: count
value G) of the voltage applied to the motor 6 once during counting
when counting every time (step S106). In other words, the control
part 30 acquires the duty ratio dg once every specified time of 0.1
second.
[0225] In addition, in step S106, the control part 30 acquires the
duty ratio dg once every specified time and calculates an
accumulated value H of a difference between the duty ratio dg and
the previous maximum duty ratio dmax. The difference is a value
obtained by subtracting the duty ratio dg from the maximum duty
ratio dmax. The accumulated value H is a value obtained by adding
the latest difference to the last accumulated value H, and is
updated every time when adding 1 to the count value G.
[0226] FIG. 19 is a graph illustrating the relationship between the
count value G and the accumulated value H in association with the
detection 6. In the graph of FIG. 19, the horizontal axis
represents the count value G, and the vertical axis represents the
accumulated value H. Referring to FIG. 19, when the washings Q are
not biased in the dewatering drum 4 due to relatively small
eccentricity, the duty ratio gradually decreases after the maximum
duty ratio dmax is generated, as described above. Thus, since the
difference between the duty ratio dg and the maximum duty ratio
dmax is gradually increased, the accumulated value H is increased
as shown by the solid line. On the other hand, when the washings Q
are biased in the dewatering drum 4 due to relatively large
eccentricity, the duty ratio after the maximum duty ratio dmax is
generated can hardly decrease, as described above. Therefore, since
the difference between the duty ratio dg and the maximum duty ratio
dmax can hardly increase, the accumulated value H can hardly
increase as shown by the dotted line.
[0227] A specified threshold is set for the accumulated value H.
The threshold is obtained from the following formula (5) using the
count value G added with 1 every specified time and the maximum
duty ratio dmax as variables.
Threshold=(K.times.G-L)-M.times.(N-dmax) Formula (5)
[0228] K, L, M and N in the formula (5) are constants previously
obtained from experiments and the like, and are stored in the
memory 32. As shown by dot dash lines in FIG. 19, the threshold is
changed in a manner of increasing as the count value G increases.
The threshold can be pre-stored in the memory 32, and can also be
calculated by the control part 30 based on the formula (5) every
time when the count value G is changed.
[0229] Referring to FIG. 18, when the count value G reaches the
timing of, for example, 20, and specifically, reaches the timing of
start of longitudinal resonance (step S107: Yes), the control part
30 confirms whether the latest accumulated value H is smaller than
the specified threshold value obtained from the formula (5) (step
S108). When the accumulated value H is smaller than the threshold
(step S108: Yes), the control part 30 determines whether the
washings Q are biased in the dewatering drum 4 and stops the motor
6 (step S109). Therefore, the rotation of the dewatering drum 4 is
stopped. After the motor 6 is stopped, similar to the detections 1
to 4, the processing of steps S11 to S18 can also be executed
(referring to FIG. 5B).
[0230] When the accumulated value H is no less than the specified
threshold (step S108: No) and the count value G reaches the
specified value (for example, 81) (step S110: Yes), the rotating
speed of the motor 6 reaches 240 rpm and the motor 6 is in a state
of rotating at the constant speed of 240 rpm. In this case, the
control part 30 terminates the detection 6 (step S111).
[0231] In this way, the accuracy for detecting whether the washings
Q are biased can be improved by monitoring the detection 6 for the
index representing the relative change between the duty ratio dg
after the maximum duty ratio dmax is generated and the maximum duty
ratio dmax, i.e., the accumulated value H.
[0232] Particularly, in the detection 6, the duty ratio is set in
such a manner that the maximum duty ratio dmax is generated at a
rotating speed slightly lower than the longitudinal resonance
rotating speed. At this time, the longitudinal resonance occurs at
an earlier timing after the maximum duty ratio dmax is generated.
As a result, the phenomenon that the accumulated value H can hardly
increase occurs earlier. Therefore, that the washings Q are biased
in the dewatering drum 4 can be detected early and correctly. In
addition, when the maximum duty ratio dmax is generated at the
longitudinal resonance rotating speed, a bad condition that the
subsequent change of the rotating speed becomes unstable may
appear. However, in the present embodiment, such a bad condition
can be suppressed by generating the maximum duty ratio dmax at the
rotating speed slightly lower than the longitudinal resonance
rotating speed.
[0233] FIG. 20 is a graph illustrating the relationship between the
count value G and the duty ratio in association with the detection
6. In the graph of FIG. 20, the horizontal axis represents the
count value G and the vertical axis represents the duty ratio.
Referring to FIG. 20, when the load is relatively large, as shown
by the solid line, a relatively large duty ratio is required to
increase the rotating speed of the motor 6 at a constant
acceleration, and the maximum duty ratio dmax is increased
accordingly. On the other hand, when the load is relatively small,
as shown by the dotted line, a relatively small duty ratio is
required to increase the rotating speed of the motor 6 at the
constant accelerated speed, and the maximum duty ratio dmax s
decreased accordingly. Therefore, for the difference between the
duty ratio dg after the specified time from generation of the
maximum duty ratio dmax and the maximum duty ratio dmax, a
difference R when the load is relatively small is apparently
smaller than a difference S when the load is relatively large. So,
compared with the case of a large load, it is conceivable that it
is more difficult for the accumulated value H in the case of a
small to increase, and the accumulated value H is also smaller than
the threshold even if the washings Q are not biased. In this way,
when the load is relatively small, the dewatering operation may be
stopped due to false detection of presence of the bias of the
washings Q.
[0234] Therefore, the threshold is obtained from the formula (5)
using the count value G and the maximum duty ratio dmax as the
variables, as described above. Since the maximum duty ratio dmax
varies depending on the magnitude of the load of the washings Q in
the dewatering drum 4, the threshold is determined differently
based on the load. Therefore, since whether the washings Q are
biased is detected based on an optimal threshold corresponding to
the magnitude of the load of the washings Q in the dewatering drum
4 in the detection 6, the false detection can be prevented even if
the load is relatively small. Thus, the accuracy for detecting
whether the washings Q are biased can be further improved.
[0235] In above embodiments, the motor 6 is controlled through the
duty ratio on a premise that the motor 6 is a variable frequency
motor. However, when the motor 6 is a brush motor, the motor 6 is
controlled through the voltage applied to the motor 6 instead of
the duty ratio.
[0236] In addition, although the rotating speed in the above
description has specific values, such as 120 rpm, 240 rpm or 800
rpm, these specific values are values that vary according to
performance of the dewatering machine 1. In addition, sometimes the
duty ratio may be obtained for making various determinations in the
above description. However, the duty ratio can be original data of
the obtained duty ratio, can also be a corrected value that is
corrected as needed, and can further be a value calculated based on
the duty ratio like the moving accumulated value Cn.
[0237] In addition, the dewatering drum 4 of above embodiments can
be configured vertically in a manner of rotating by using an axis
16 extending in the up-down direction X as a center. However, the
dewatering drum 4 can also be configured obliquely in a manner of
obliquely extending the axis 16 relative to the up-down direction
X.
* * * * *