U.S. patent application number 15/535034 was filed with the patent office on 2017-11-09 for dewatering machine.
The applicant listed for this patent is HAIER ASIA CO., LTD., QINGDAO HAIER WASHING MACHINE CO., LTD.. Invention is credited to Tomonari KAWAGUCHI, Hiroki SATO.
Application Number | 20170321363 15/535034 |
Document ID | / |
Family ID | 56106744 |
Filed Date | 2017-11-09 |
United States Patent
Application |
20170321363 |
Kind Code |
A1 |
KAWAGUCHI; Tomonari ; et
al. |
November 9, 2017 |
DEWATERING MACHINE
Abstract
A dewatering machine including: a dewatering tank, formed in a
cylindrical shape with a central axis extending in a direction
inclined relative to an up-down direction; a balancing ring
coaxially arranged in the dewatering tank, liquid for achieving
rotational balance of the dewatering tank is contained in the
balancing ring and flows freely; a control part. The control part
causes the dewatering tank to rotate at a rotating speed lower than
a lowest rotating speed at which the dewatering tank resonates in a
dewatering preparation stage of washings, so as to detect a biased
position of the washings, causes the dewatering tank to stop
rotating immediately before the washings biased in the dewatering
tank are positioned at an opposite side of liquid biased downward
in the balancing rings to a lower side, relative to the central
axis.
Inventors: |
KAWAGUCHI; Tomonari; (Tokyo,
JP) ; SATO; Hiroki; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HAIER ASIA CO., LTD.
QINGDAO HAIER WASHING MACHINE CO., LTD. |
Tokyo
Qingdao, Shandong |
|
JP
CN |
|
|
Family ID: |
56106744 |
Appl. No.: |
15/535034 |
Filed: |
December 11, 2015 |
PCT Filed: |
December 11, 2015 |
PCT NO: |
PCT/CN2015/097173 |
371 Date: |
June 9, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D06F 23/06 20130101;
D06F 33/00 20130101; D06F 34/28 20200201; D06F 37/304 20130101;
D06F 39/087 20130101; D06F 37/20 20130101; D06F 37/36 20130101 |
International
Class: |
D06F 23/06 20060101
D06F023/06; D06F 39/00 20060101 D06F039/00; D06F 37/36 20060101
D06F037/36; D06F 37/30 20060101 D06F037/30; D06F 37/20 20060101
D06F037/20; D06F 39/08 20060101 D06F039/08; D06F 33/02 20060101
D06F033/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 12, 2014 |
JP |
2014-252413 |
Claims
1. A dewatering machine, comprising: a dewatering tank, formed in a
cylindrical shape with a central axis extending in a direction
inclined relative to an up-down direction, wherein the dewatering
tank is configured to contain washings, and rotate around the
central axis so as to dewater the washings; a balancing ring,
formed in a hollow annular shape, wherein the balancing ring is
coaxially arranged in the dewatering tank, and liquid for achieving
rotational balance of the dewatering tank is contained in the
balancing ring and flows freely; and a dewatering preparation unit,
configured to cause the dewatering tank, in a dewatering
preparation stage for the washings, to rotate at a rotating speed
lower than a lowest rotating speed at which the dewatering tank
resonates, so as to detect a biased position of the washings in the
dewatering tank; and cause the dewatering tank to stop rotating
immediately before the washings biased in the dewatering tank are
positioned, relative to the central axis, at an opposite side of
the liquid biased downward in the balancing ring.
2. A dewatering machine, comprising: a dewatering tank, formed in a
cylindrical shape with a central axis extending in a direction
inclined relative to an up-down direction, wherein the dewatering
tank is configured to contain washings, and rotate around the
central axis so as to dewater the washings; an electric motor,
configured to cause the dewatering tank to rotate; an information
value acquisition unit, configured to, when the electric motor is
in an acceleration state of accelerating to a target rotating speed
used for formally dewatering the washings, sequentially acquire an
information value that should be decreased as a rotating speed of
the electric motor increases; a counting unit, configured to add a
count value with an initial value of zero by 1 once the information
value acquisition unit acquires the information value; a
calculation unit, configured to calculate an accumulated value of a
difference between the information value and a previous information
value under a condition that the information value is larger than
the previous information value; a determination unit, configured to
determine that the washings are biased in the dewatering tank under
a condition that the accumulated value when the count value is a
specified value reaches a first threshold when the count value is
the specified value; and a stopping unit, configured to cause the
dewatering tank to stop rotating when it is determined by the
determination unit that the washings are biased.
3. The dewatering machine according to claim 2, further comprising
an information correction unit, wherein information correction unit
is configured to correct the information value through moving
average before the accumulated value is calculated by the
calculation unit.
4. The dewatering machine according to claim 2, further comprising
an execution unit, wherein the execution unit is configured to
alternatively execute any of a restarting process and a correction
process under a condition that the dewatering tank is stopped
rotating through the stopping unit, wherein the restarting process
is a process for restarting to dewater the washings by causing the
dewatering tank to rotate again, and the correction process is a
process for correcting the biasing of the washings in the
dewatering tank; and the execution unit is configured to select to
execute the correction process rather than selecting to execute the
restarting process in the following situation: the restarting
process has been executed for a specified number, and the
dewatering tank is caused to stop rotating by the stopping
unit.
5. The dewatering machine according to claim 2, further comprising
an acceleration unit, wherein the acceleration unit causes the
electric motor to accelerate in three stages including a first
acceleration stage, a second acceleration stage and a third
acceleration stage, wherein the first acceleration stage refers to
an acceleration stage, in which the motor accelerates toward the
target rotating speed from starting rotating until the rotating
speed of the motor reaches a first rotating speed, wherein the
first rotating speed is higher than a rotating speed at which the
dewatering tank resonates transversely and lower than a rotating
speed at which the dewatering tank resonates longitudinally, the
second acceleration stage is an acceleration stage, in which the
rotating speed of the motor increases from the first rotating speed
to a second rotating speed higher than the first rotating speed,
the third acceleration stage is an acceleration stage, in which the
rotating speed of the motor increases from the second rotating
speed to the target rotating speed, the first threshold is
independently set in the first acceleration stage, the second
acceleration stage and the third acceleration stage respectively,
and the information value acquisition unit is configured to acquire
the information value in the first acceleration stage, the second
acceleration stage and the third acceleration stage respectively,
the counting unit causes the count value to be added by 1 and
calculates the accumulated value, and the determination unit
determines that the washings are biased in the dewatering tank when
the accumulated value reaches the first threshold.
6. The dewatering machine according to claim 5, further comprising:
a duty ratio acquisition unit, configured to acquire a duty ratio
of voltage applied to the motor at each specified time in the third
acceleration stage; and a transformation unit, configured to
transform the duty ratio acquired by the duty ratio acquisition
unit into a specified index value, when the index value reaches a
second threshold for a corresponding time, the determination unit
determines that the washings are biased in the dewatering tank.
7. The dewatering machine according to claim 6, further comprising
a threshold modification unit, wherein the threshold modification
unit is configured to modify the second threshold according to the
accumulated value in at least one acceleration stage of the first
acceleration stage, the second acceleration stage and the third
acceleration stage.
8. The dewatering machine according to claim 5, wherein when a
variation of the accumulated value reaches a third threshold, the
determination unit determines that the washings are biased in the
dewatering tank.
9. A dewatering machine, comprising: a dewatering tank, formed in a
cylindrical shape with a central axis extending in a direction
inclined relative to an up-down direction, wherein the dewatering
tank is configured to contain washings, and rotate around the
central axis so as to dewater the washings; an outer tank,
configured to contain the dewatering tank; an electric motor,
configured to cause the dewatering tank to rotate; a determination
unit, configured to determine that the washings are biased in the
dewatering tank when an information value, relevant to a rotation
state of the electric motor before a rotating speed of the electric
motor reaches a target rotating speed used for formally dewatering
the washings, reaches a threshold; a detection unit, configured to
mechanically detect eccentric rotation of the dewatering tank by
contacting the outer tank when the dewatering tank eccentrically
rotates along with biasing of the washings in the dewatering tank
and the outer tank is caused to vibrate; and a stopping unit,
configured to cause the dewatering tank to stop rotating in one of
the following situations: it is determined by the determination
unit that the washings are biased; the eccentric rotation of the
dewatering tank is detected by the detection unit.
10. (canceled)
11. The dewatering machine according to claim 3, further comprising
an execution unit, wherein the execution unit is configured to
alternatively execute any of a restarting process and a correction
process under a condition that the dewatering tank is stopped
rotating through the stopping unit, wherein the restarting process
is a process for restarting to dewater the washings by causing the
dewatering tank to rotate again, and the correction process is a
process for correcting the biasing of the washings in the
dewatering tank; and the execution unit is configured to select to
execute the correction process rather than selecting to execute the
restarting process in the following situation: the restarting
process has been executed for a specified number, and the
dewatering tank is caused to stop rotating by the stopping
unit.
12. The dewatering machine according to claim 3, further comprising
an acceleration unit, wherein the acceleration unit causes the
electric motor to accelerate in three stages including a first
acceleration stage, a second acceleration stage and a third
acceleration stage, wherein the first acceleration stage refers to
an acceleration stage, in which the motor accelerates toward the
target rotating speed from starting rotating until the rotating
speed of the motor reaches a first rotating speed, wherein the
first rotating speed is higher than a rotating speed at which the
dewatering tank resonates transversely and lower than a rotating
speed at which the dewatering tank resonates longitudinally, the
second acceleration stage is an acceleration stage, in which the
rotating speed of the motor increases from the first rotating speed
to a second rotating speed higher than the first rotating speed,
the third acceleration stage is an acceleration stage, in which the
rotating speed of the motor increases from the second rotating
speed to the target rotating speed, the first threshold is
independently set in the first acceleration stage, the second
acceleration stage and the third acceleration stage respectively,
and the information value acquisition unit is configured to acquire
the information value in the first acceleration stage, the second
acceleration stage and the third acceleration stage respectively,
the counting unit causes the count value to be added by 1 and
calculates the accumulated value, and the determination unit
determines that the washings are biased in the dewatering tank when
the accumulated value reaches the first threshold.
13. The dewatering machine according to claim 4, further comprising
an acceleration unit, wherein the acceleration unit causes the
electric motor to accelerate in three stages including a first
acceleration stage, a second acceleration stage and a third
acceleration stage, wherein the first acceleration stage refers to
an acceleration stage, in which the motor accelerates toward the
target rotating speed from starting rotating until the rotating
speed of the motor reaches a first rotating speed, wherein the
first rotating speed is higher than a rotating speed at which the
dewatering tank resonates transversely and lower than a rotating
speed at which the dewatering tank resonates longitudinally, the
second acceleration stage is an acceleration stage, in which the
rotating speed of the motor increases from the first rotating speed
to a second rotating speed higher than the first rotating speed,
the third acceleration stage is an acceleration stage, in which the
rotating speed of the motor increases from the second rotating
speed to the target rotating speed, the first threshold is
independently set in the first acceleration stage, the second
acceleration stage and the third acceleration stage respectively,
and the information value acquisition unit is configured to acquire
the information value in the first acceleration stage, the second
acceleration stage and the third acceleration stage respectively,
the counting unit causes the count value to be added by 1 and
calculates the accumulated value, and the determination unit
determines that the washings are biased in the dewatering tank when
the accumulated value reaches the first threshold.
14. The dewatering machine according to claim 6, wherein when a
variation of the accumulated value reaches a third threshold, the
determination unit determines that the washings are biased in the
dewatering tank.
15. The dewatering machine according to claim 7, wherein when a
variation of the accumulated value reaches a third threshold, the
determination unit determines that the washings are biased in the
dewatering tank.
16. The dewatering machine according to claim 9, further comprising
a threshold correction unit, configured to correct the threshold in
one of the following situations: a difference between the
information value and the threshold is above the specified value
when the eccentric rotation of the dewatering tank is detected by
the detection unit; it is determined by the determination unit that
the washings are biased before the eccentric rotation is detected
by the detection unit.
17. The dewatering machine according to claim 9, further comprising
a suspending unit, configured to suspend an operation performed by
the stopping unit for stopping the rotation of the dewatering tank,
until a detection number of the detection unit reaches a specified
number before it is determined by the determination unit that the
washings are biased.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a dewatering machine.
BACKGROUND
[0002] A washing machine with a dewatering function is disclosed in
the following patent literature 1. In the washing machine, as for a
cylindrical washing tank for containing washings, a central axis of
the washing tank is obliquely arranged relative to a plumb line.
Therefore, an upper part of the washing tank is obliquely
configured in a manner of protruding towards a front side of the
washing machine.
EXISTING TECHNICAL LITERATURE
Patent Literature
[0003] Patent literature 1: Japanese Patent Application Laid-open
No. 2000-312795
Problems to be Solved by the Disclosure
[0004] In a dewatering machine in which a dewatering tank for
containing washings is biased like the washing machine in patent
literature 1, the washings are easy to bias in the dewatering tank.
If dewatering operation is conducted in a state that the washings
are biased, the dewatering tank will conduct eccentric rotation,
thereby causing a vibration. Therefore, in the dewatering machine,
it is aimed to inhibit the eccentric rotation of the dewatering
tank early, so as to avoid vibration as much as possible.
SUMMARY
[0005] The present disclosure is made on the basis of the
background and aims to provide a washing machine capable of
inhibiting eccentric rotation of a biased dewatering tank
early.
Solutions for the Problems
[0006] The present disclosure provides a dewatering machine,
including: a dewatering tank, formed in a cylindrical shape with a
central axis extending in a direction inclined relative to an
up-down direction, the dewatering tank is configured to contain
washings, and rotate around the central axis so as to dewater the
washings; a balancing ring, formed in a hollow annular shape, the
balancing ring is coaxially arranged in the dewatering tank, and
liquid for achieving rotational balance of the dewatering tank is
contained in the balancing ring and flows freely; and a dewatering
preparation unit, configured to cause the dewatering tank, in a
dewatering preparation stage for the washings, to rotate at a
rotating speed lower than a lowest rotating speed at which the
dewatering tank resonates, so as to detect a biased position of the
washings in the dewatering tank; and cause the dewatering tank to
stop rotating immediately before the washings biased in the
dewatering tank are positioned, relative to the central axis, at an
opposite side of the liquid biased downward in the balancing
ring.
[0007] In addition, the present disclosure provides a dewatering
machine, including: a dewatering tank, formed in a cylindrical
shape with a central axis extending in a direction inclined
relative to an up-down direction, the dewatering tank is configured
to contain washings, and rotate around the central axis so as to
dewater the washings; an electric motor, configured to cause the
dewatering tank to rotate; an information value acquisition unit,
configured to, when the electric motor is in an acceleration state
of accelerating to a target rotating speed used for formally
dewatering the washings, sequentially acquire an information value
that should be decreased as a rotating speed of the electric motor
increases; a counting unit, configured to add a count value with an
initial value of zero by 1 once the information value acquisition
unit acquires the information value; a calculation unit, configured
to calculate an accumulated value of a difference between the
information value and a previous information value under a
condition that the information value is larger than the previous
information value; a determination unit, configured to determine
that the washings are biased in the dewatering tank when the
accumulated value with the count value of a specified value reaches
a first threshold with the count value of the specified value; and
a stopping unit, configured to cause the dewatering tank to stop
rotating when it is determined by the determination unit that the
washings are biased.
[0008] In addition, the dewatering machine according to the present
disclosure further includes an information correction unit,
configured to correct the information value through moving average
before the accumulated value is calculated by the calculation
unit.
[0009] In addition, the dewatering machine according to the present
disclosure further includes an execution unit, the execution unit
is configured to alternatively execute any of a restarting process
and a correction process under a condition that the dewatering tank
is stopped rotating through the stopping unit, the restarting
process is a process for restarting to dewater the washings by
causing the dewatering tank to rotate again, and the correction
process is a process for correcting the biasing of the washings in
the dewatering tank; and the execution unit is configured to select
to execute the correction process rather than selecting to execute
the restarting process in the following situation: the restarting
process has been executed for a specified number, and the
dewatering tank is caused to stop rotating by the stopping unit
[0010] In addition, the dewatering machine according to the present
disclosure further includes an acceleration unit, and the
acceleration unit causes the electric motor to accelerate in three
stages including a first acceleration stage, a second acceleration
stage and a third acceleration stage. The first acceleration stage
refers to an acceleration stage, in which the motor accelerates
toward the target rotating speed from starting rotating until the
rotating speed of the motor reaches a first rotating speed, the
first rotating speed is higher than a rotating speed at which the
dewatering tank resonates transversely and lower than a rotating
speed at which the dewatering tank resonates longitudinally. The
second acceleration stage is an acceleration stage, in which the
rotating speed of the motor increases from the first rotating speed
to a second rotating speed higher than the first rotating speed.
The third acceleration stage is an acceleration stage, in which the
rotating speed of the motor increases from the second rotating
speed to the target rotating speed. The first threshold is
independently set in the first acceleration stage, the second
acceleration stage and the third acceleration stage respectively,
and the information value acquisition unit is configured to acquire
the information value in the first acceleration stage, the second
acceleration stage and the third acceleration stage respectively,
the counting unit causes the count value to be added by 1 and
calculates the accumulated value, and the determination unit
determines that the washings are biased in the dewatering tank when
the accumulated value reaches the first threshold.
[0011] In addition, the dewatering machine according to the present
disclosure further includes a duty ratio acquisition unit,
configured to acquire a duty ratio of voltage applied to the motor
at each specified time in the third acceleration stage; and a
transformation unit, configured to transform the duty ratio
acquired by the duty ratio acquisition unit into a specified index
value. When the index value reaches a second threshold for a
corresponding time, the determination unit determines that the
washings are biased in the dewatering tank.
[0012] In addition, the dewatering machine according to the present
disclosure further includes a threshold modification unit,
configured to modify the second threshold according to the
accumulated value in at least one acceleration stage of the first
acceleration stage, the second acceleration stage and the third
acceleration stage.
[0013] In addition, in the present disclosure, when a variation of
the accumulated value reaches a third threshold, the determination
unit determines that the washings are biased in the dewatering
tank.
[0014] In addition, the present disclosure provides a dewatering
machine, including: a dewatering tank, formed in a cylindrical
shape with a central axis extending in a direction inclined
relative to an up-down direction, the dewatering tank is configured
to contain washings, and rotate around the central axis so as to
dewater the washings; an outer tank, configured to contain the
dewatering tank; an electric motor, configured to cause the
dewatering tank to rotate; a determination unit, configured to
determine that the washings are biased in the dewatering tank when
an information value, relevant to a rotation state of the electric
motor before a rotating speed of the electric motor reaches a
target rotating speed used for formally dewatering the washings,
reaches a threshold; a detection unit, configured to mechanically
detect eccentric rotation of the dewatering tank by contacting the
outer tank when the dewatering tank eccentrically rotates along
with biasing of the washings in the dewatering tank and the outer
tank is caused to vibrate; a stopping unit, configured to cause the
dewatering tank to stop rotating in one of the following
situations: it is determined by the determination unit that the
washings are biased; the eccentric rotation of the dewatering tank
is detected by the detection unit; and a threshold correction unit,
configured to correct the threshold in one of the following
situations: a difference between the information value and the
threshold is above the specified value when the eccentric rotation
of the dewatering tank is detected by the detection unit; it is
determined by the determination unit that the washings are biased
before the eccentric rotation is detected by the detection
unit.
[0015] In addition, the present disclosure provides a dewatering
machine, including: a dewatering tank, formed in a cylindrical
shape with a central axis extending in a direction inclined
relative to an up-down direction, the dewatering tank is configured
to contain washings, and rotate around the central axis so as to
dewater the washings; an outer tank, configured to contain the
dewatering tank; an electric motor, configured to cause the
dewatering tank to rotate; a determination unit, configured to
determine that the washings are biased in the dewatering tank when
an information value, relevant to a rotation state of the electric
motor before a rotating speed of the electric motor reaches a
target rotating speed used for formally dewatering the washings,
reaches a threshold; a detection unit, configured to mechanically
detect eccentric rotation of the dewatering tank by contacting the
outer tank when the dewatering tank eccentrically rotates along
with biasing of the washings in the dewatering tank and the outer
tank is caused to vibrate; a stopping unit, configured to cause the
dewatering tank to stop rotating in one of the following
situations: it is determined by the determination unit that the
washings are biased; the eccentric rotation of the dewatering tank
is detected by the detection unit; and a suspending unit,
configured to suspend an operation performed by the stopping unit
for stopping the rotation of the dewatering tank, until a detection
number of the detection unit reaches a specified number before it
is determined by the determination unit that the washings are
biased.
Effects of Disclosure
[0016] According to the present disclosure, since the dewatering
tank of the dewatering machine has a cylindrical shape with a
central axis extending along a direction inclined relative to an
up-down direction, the dewatering tank is arranged obliquely. A
hollow annular balancing ring is coaxially arranged on the
dewatering tank. Thus, in a static state of the dewatering tank,
liquid contained in the balancing ring is biased downwards in the
balancing ring.
[0017] In the dewatering tank, washings are assumed to be biased in
a rotating direction of the dewatering tank in a same position as
the liquid biased downwards in the balancing ring. In the state,
when rotation of the dewatering tank is started to dewater the
washings, the dewatering tank eccentrically rotates from the
beginning of the rotation.
[0018] Therefore, in the dewatering machine, in a dewatering
preparation stage, a dewatering preparation unit causes the
dewatering tank to rotate at a very low speed lower than a maximum
rotating speed at which the dewatering tank resonates, so as to
detect a biased position of the washings in the dewatering tank in
a rotating direction. The dewatering preparation unit causes the
dewatering tank to stop rotating according to the detected biased
position immediately before the washings biased in the dewatering
tank will be positioned at an opposite side of the liquid biased
downwards in the balancing ring, relative to the central axis.
[0019] In addition, since the dewatering tank stops rotating when
the washings biased in the dewatering tank are positioned at the
opposite side of the liquid in the balancing ring relative to the
central axis, the washings finally may come to a same side of the
liquid in the balancing ring due to no time to stop and inertial
rotation of the dewatering tank after stopping.
[0020] Therefore, if the dewatering tank stops rotating immediately
before the washings biased in the dewatering tank will be
positioned at the opposite side of the liquid in the balancing ring
relative to the central axis, the washings biased in the dewatering
tank and the liquid biased downwards in the balancing ring can be
maintained in a state of being positioned on approximately opposite
sides relative the central axis. After such preparation stage, when
the dewatering tank rotates to dewater, the dewatering tank rotates
in a state that the liquid in the balancing ring and the washings
are approximately balanced. Thus, eccentric rotation of the
dewatering tank obliquely arranged can be early inhibited.
[0021] According to the present disclosure, the dewatering tank of
the dewatering machine has a cylindrical shape having the central
axis which extends along the direction inclined relative to the
up-down direction, and is arranged obliquely. In the dewatering
machine which uses a motor to rotate the dewatering tank, in a
state that the motor is accelerated to a target rotating speed for
formally dewatering the washings, information values which are
decreased with the increase of the rotating speed of the motor are
acquired successively. When the information values are obtained
each time, a count value with an initial value of zero is added by
1.
[0022] If the washings in the dewatering tank are biased, an
information value at a certain time becomes larger than a previous
information value sometimes since an information value which shall
be decreased is changed. In this case, an accumulated value of a
difference between the information value and the previous
information value is larger than zero. If the dewatering tank
continues to rotate in a state that the washings in the dewatering
tank are biased, the accumulated value becomes larger.
[0023] Moreover, when the accumulated value when the count value is
the specified value reaches a first threshold when the count value
is the specified value, it is determined that the washings are
biased in the dewatering tank, and the dewatering tank stops
rotating. Thus, under a condition that the washings are biased in
the obliquely arranged dewatering tank, eccentric rotation of the
dewatering tank may be inhibited early in an acceleration state of
the motor.
[0024] According to the present disclosure, since an information
value used in calculation of the accumulated value is corrected
through moving average before calculation of the accumulated value,
the information value is a high accuracy value of eliminating an
error. Thus, the accumulated value with high accuracy is calculated
according to the corrected information value, and whether the
washings are biased is detected through the accumulated value with
high accuracy, so that eccentric rotation of the dewatering tank
may be inhibited early.
[0025] According to the present disclosure, under a condition that
the washings are biased in the dewatering tank and the dewatering
tank stops rotating, the restarting process or the correction
process is executed. The restarting process is a process for
restarting to dewater the washing by enabling the dewatering tank
to rotate again, and the correction process is a process for
correcting washing biasing in the dewatering tank.
[0026] Dewatering is started again through the restarting process
under a condition that washing biasing is small to an extent
without generating eccentric rotation of the dewatering tank, so
that time used by the whole dewatering process may be shortened as
much as possible. Under a condition that washing biasing is large
to an extent that eccentric rotation of the dewatering tank is
still generated, washing biasing may be reliably corrected through
the correction process.
[0027] Under a condition that the restarting process is executed
for the specified number and the dewatering tank stops rotating,
washing biasing is large to an extent needing to be corrected. In
this case, the correction process is quickly executed without
spending time on carrying out the restarting process repeatedly and
stopping rotation of the dewatering tank, so that biasing may be
reliably corrected. Thus, eccentric rotation of the dewatering tank
may be inhibited early.
[0028] According to the present disclosure, in the first
acceleration stage, the second acceleration stage and the third
acceleration stage of the motor from starting rotation to reaching
the target rotating speed, the accumulated values are respectively
calculated, and when the accumulated values reach the corresponding
first thresholds in the first acceleration stage, the second
acceleration stage and the third acceleration stage respectively,
washing biasing in the dewatering tank may be determined, so that
the dewatering tank stops rotating. Namely, since the biasing of
the washings is detected in the first acceleration stage after the
motor starts to rotate, eccentric rotation of the dewatering tank
may be inhibited early. Furthermore, since the biasing of the
washings is detected in three stages according to a sequence of the
first acceleration stage, the second acceleration stage and the
third acceleration stage, the condition of washing biasing may be
reliably detected, and eccentric rotation of the dewatering tank is
inhibited as early as possible.
[0029] According to the present disclosure, in the third
acceleration stage, when the duty ratio acquired at each specified
moment is transformed into a specified index value, and the index
value reaches a second threshold at a corresponding moment, it is
determined that the washings are biased in the dewatering tank.
That is, in the third acceleration stage, since the condition
whether the washing is biased in the dewatering tank is double
detected by adopting a mode of the information values and the first
thresholds and adopting a mode of the duty ratio and the second
thresholds, eccentric rotation of the dewatering tank may be
reliably inhibited early.
[0030] According to the present disclosure, since the second
threshold is properly changed according to the accumulated value in
at least one acceleration stage of the first acceleration stage,
the second acceleration stage and the third acceleration stage,
whether the washings are biased may be detected with high accuracy
through the second threshold changed with combination of a
situation of the dewatering tank, and eccentric rotation of the
dewatering tank is inhibited early.
[0031] According to the present disclosure, whether the washings
are biased may be double detected through a mode whether the
accumulated value reaches the first threshold and whether a
variation of the accumulated value reaches the third threshold. In
this case, whether the dewatering tank is in a state of large
amplitude vibration, eccentric rotation of the dewatering tank may
be reliably inhibited early according to the variation of the
accumulated value though the accumulated value may be small without
reaching the first threshold.
[0032] According to the present disclosure, the dewatering tank of
the dewatering machine is in a cylindrical shape with a central
axis extending in the direction inclined relative to the up-down
direction and is obliquely arranged. Whether the washings are
biased in the dewatering tank is double detected through an
electric mode based on a relationship between the information value
relative to the rotation state of the motor and the threshold and a
mechanical mode based on contact between the detection unit and the
outer tank.
[0033] In the dewatering machine in the shipment stage, due to an
inclined difference of the dewatering tanks among individual
dewatering machines, some dewatering machines may have a condition
that the threshold is not correct. Thus, the threshold is corrected
under the following situation: a difference between the information
value when the detection unit detects eccentric rotation of the
dewatering tank and a threshold is above the specified value, or
the determination unit determines that the washings are biased
before eccentric rotation is detected by the detection unit. Thus,
in the dewatering process after the threshold is corrected, in the
electric mode, whether the washings are biased is detected with
high accuracy through the corrected threshold, so that eccentric
rotation of the dewatering tank is inhibited early.
[0034] According to the present disclosure, the dewatering tank of
the dewatering machine is in the cylindrical shape with the central
axis extending in the direction inclined relative to up-down
direction and is obliquely arranged. Whether the washings are
biased in the dewatering tank is double detected through the
electric mode based on a relationship between the information value
relative to the rotation state of the motor and the threshold and a
mechanical mode based on contact between the detection unit and the
outer tank.
[0035] It is assumed that vibration of the dewatering tank is not
too large, but due to the moving mode of the outer tank, the
detection unit easily contacts the outer tank to generate error
detection in the mechanical mode to cause the dewatering tank to
stop rotating. Thus, until the detection number of the detection
unit reach the specified number before the determination unit
determines that the washings are biased, rotation stopping of the
dewatering tank is suspended. Thus, not only the dewatering tank is
prevented from stopping rotating due to error detection of the
mechanical mode, but also eccentric rotation of the dewatering tank
may be inhibited early.
BRIEF DESCRIPTION OF DRAWINGS
[0036] FIG. 1 is a schematic longitudinal sectional right side view
illustrating a dewatering machine according to an embodiment of the
present disclosure.
[0037] FIG. 2 is a block diagram illustrating an electric structure
of a dewatering machine.
[0038] FIG. 3 is a sequence diagram illustrating a state of an
output signal of a Hall IC forming a rotating speed reading
apparatus for reading a rotating speed of a motor.
[0039] FIG. 4 is a sequence diagram illustrating a state of a
rotating speed of a motor in a dewatering operation process
implemented in a dewatering machine.
[0040] FIG. 5 is a schematic diagram illustrating an interior of a
dewatering tank.
[0041] FIG. 6 is a sequence diagram illustrating a state of a
rotating speed of a motor at a preparation stage of dewatering
operation.
[0042] FIG. 7 is a flow chart illustrating a control action at the
preparation stage of dewatering operation.
[0043] FIG. 8 is a flow chart illustrating a control action in a
first acceleration stage of a motor in a dewatering operation
process.
[0044] FIG. 9A is a flow chart illustrating a control action
related to detection 1 to detection 3 for detecting washings
biasing in the dewatering tank in a first acceleration stage to a
third acceleration stage of a motor.
[0045] FIG. 9B is a flow chart illustrating a control action
related to detection 1 to detection 3.
[0046] FIG. 10 is a diagram illustrating a relationship between a
count value n and a moving average value Cn in combination with
detection 1 to detection 3.
[0047] FIG. 11 is a diagram illustrating a relationship between a
count value n and an accumulated value G in combination with
detection 1 to detection 3.
[0048] FIG. 12 is a flow chart illustrating a control action when a
detection result is no good (NG).
[0049] FIG. 13 is a flow chart illustrating a control action in the
second acceleration stage of the motor.
[0050] FIG. 14 is a flow chart illustrating a control action in the
third acceleration stage of a motor.
[0051] FIG. 15 is a flow chart illustrating schemas of the
detection 4-1 and the detection 4-2 for detecting whether there is
washings biasing in the dewatering tank in the third acceleration
stage.
[0052] FIG. 16 is a flow chart illustrating a control action of the
detection 4-1.
[0053] FIG. 17 is a diagram illustrating a relationship between the
rotating speed and a moving accumulated value Cm in combination
with detection 4-1 and detection 4-2.
[0054] FIG. 18 is a flow chart illustrating a control action of the
detection 4-2.
[0055] FIG. 19 is a flow chart illustrating a first modification of
a control action of the detection 3 in the third acceleration
stage.
[0056] FIG. 20 is a schematic diagram illustrating an interior of
the dewatering tank in the dewatering operation process.
[0057] FIG. 21 is a flow chart illustrating a second modification
of a control action of detection 3 in the third acceleration
stage.
[0058] FIG. 22 is a flow chart illustrating a control action of a
third modification in the dewatering operation process.
[0059] FIG. 23 is a flow chart illustrating a control action of the
third modification.
[0060] FIG. 24 is a flow chart illustrating a control action of a
fourth modification.
[0061] FIG. 25 is a flow chart illustrating a control action of a
fifth modification.
REFERENCE NUMERALS LIST
[0062] 1: dewatering machine; 3: outer tank; 4: dewatering tank; 6:
motor; 17: central axis; 19: balancing ring; 30: control part; 34:
counter; 36: safety switch; C.sub.m: moving accumulated value;
C.sub.n: moving average value; d.sub.m: duty ratio; D.sub.n:
difference; G: accumulated value; K: inclined direction; n: count
value; Q: washings; Z: up-down direction; Z2: lower side.
DETAILED DESCRIPTION
[0063] Embodiments of the present disclosure are described in
detail by referring to the drawings below.
[0064] FIG. 1 is a schematic longitudinal sectional right side view
illustrating a dewatering machine 1 according to an embodiment of
the present disclosure. An up-down direction in FIG. 1 is referred
to as an up-down direction Z of the dewatering machine 1, and a
left-right direction in FIG. 1 is referred to as a front-rear
direction Y of the dewatering machine 1. Firstly, description is
made to summary of the dewatering machine 1. In the up-down
direction Z, an upper side is referred to as an upper side Z1, and
a lower side is referred to as a lower side Z2. In the front-rear
direction Y, a left side in FIG. 1 is referred to as a front side
Y1, and a right side in FIG. 1 is referred to as a rear side
Y2.
[0065] The dewatering machine 1 includes all apparatuses capable of
carrying out a dewatering operation of washings Q. That is, the
dewatering machine 1 not only includes an apparatus with a
dewatering function, but also includes a washing machine with a
dewatering function and a washing and drying machine. Description
is made in regard to the dewatering machine 1 by taking the washing
machine as an example below.
[0066] The dewatering machine 1 includes: a housing 2, an outer
tank 3, a dewatering tank 4, a rotary wing 5, an electric motor 6,
and a transmission mechanism 7.
[0067] The housing 2 is made of, such as, metal, and formed in a
box shape. An upper surface 2A of the housing 2 is formed to be
inclined relative to a horizontal direction (HD) in a manner of
extending to the upper side Z1 toward the rear side Y2. An opening
8 to enable the inside and outside of the housing 2 to be
communicated 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 10 consisting of a LCD operation panel and
the like is arranged in an area closer the front side Y1 than the
opening 8 on the upper surface 2A. A user could select a dewatering
condition freely, or make indications, such as an indication of
starting to run, an indication of stopping running, to the
dewatering machine 1, by operating the operation part 10.
[0068] The outer tank 3 is made of, such as, resin, and formed in a
cylindrical shape having a bottom. The outer tank 3 has: a
circumferential wall 3A, which is roughly cylindrical and
configured along an inclined direction K inclined toward the front
side Y1 relative to the up-down direction Z; a bottom wall 3B,
configured to block a hollow part of the circumferential wall 3A
from the lower side Z2; 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 Z1 of
the circumferential wall 3A. The inclined direction K presents
inclination not only relative to the up-down direction Z, but also
relative to the horizontal direction (HD). An entrance 11
communicated with the hollow part of the circumferential wall 3A
from the upper side Z1 is formed inside the annular wall 3C. The
entrance 11 is opposite to the opening 8 of the housing 2 from the
lower side Z2, and the entrance 11 and the opening 8 are in a
communicated state. A door 12 for opening and closing the entrance
11 is arranged on the annual wall 3C. The bottom wall 3B is formed
in a circulate plate shape which is orthogonal to the inclined
direction K and obliquely extends relative to the horizontal
direction (HD). A through hole 3D penetrating through the bottom
wall 3B is formed in a circle center of the bottom wall 3B.
[0069] Water can be stored in the outer tank 3. A water feeding
pipeline 13 connected with a faucet of tap water is connected with
the outer tank 3 from the upper side Z1, so that the tap water is
fed to the outer tank 3 through the water feeding pipeline 13. A
feeding valve 14 which can be opened and closed to start or stop
water feeding is arranged in a midway of the water feeding pipeline
13. A drainage pipeline 15 is connected with the outer tank 3 from
the lower side Z2, and the water in the outer tank 3 is discharged
outside the machine from the drainage pipeline 15. A drainage valve
16 which can be opened and closed to start or stop drainage is
arranged in a midway of the drainage pipeline 15.
[0070] The dewatering tank 4 is made of, such as, metal, and has a
central axis 17 extending along the inclined direction K. The
dewatering tank 4 is formed in a cylindrical shape having a bottom
smaller than that of the outer tank 3, and can accommodate the
washings Q internally. The dewatering tank 4 has a roughly
cylindrical circumferential wall 4A arranged along the inclined
direction K and a bottom wall 4B for blocking a hollow part of the
circumferential wall 4A from the lower side Z2.
[0071] An internal circumferential surface of the circumferential
wall 4A is an internal circumferential surface of the dewatering
tank 4. An upper end of the internal circumferential surface of the
circumferential wall 4A is an entrance 18 for enabling the hollow
part of the circumferential wall 4A to expose to the upper side Z1.
The entrance 18 is opposite to the entrance 11 of the outer tank 3
from the lower side Z2, and the entrance 18 and the entrance 11 are
in a communicated state. The entrances 11 and 18 are opened and
closed through the door 12 together. A user of the dewatering
machine 1 takes the washings Q in and out of the dewatering tank 4
through the opened opening 8 and the entrances 11 and 18.
[0072] The dewatering tank 4 is coaxially accommodated in the outer
tank 3, and is obliquely arranged relative to the up-down direction
Z and the horizontal direction HD. The dewatering tank 4
accommodated in the outer tank 3 can rotate around the central axis
17. A plurality of through holes which are not shown are formed in
the circumferential wall 4A and the bottom wall 4B of the
dewatering tank 4, and the water in the outer tank 3 can flow
between the outer tank 3 and the dewatering tank 4 through the
through holes. Therefore, a water level in the outer tank 3 is
consistent with a water level in the dewatering tank 4.
[0073] A balancing ring 19 formed in a hollow annular shape is
coaxially arranged at the upper end of the circumferential wall 4A,
and is used for reducing vibration of the dewatering tank 4 when
the dewatering tank 4 rotates so as to obtain rotational balance of
the dewatering tank 4. Liquids for obtaining the rotational balance
of the dewatering tank 4, such as saline water, are accommodated in
an annular cavity 19A in the balancing ring 19 in a free flow
manner.
[0074] The bottom wall 4B of the dewatering tank 4 is formed in a
circulate plate shape extending with the bottom wall 3B of the
outer tank 3 in parallel roughly across the gap in the upper side
Z1, and a through hole 4C penetrating through the bottom wall 4B is
formed at a circle center of the bottom wall 4B consistent with the
central axis 17. A tubular supporting shaft 20 surrounding the
through hole 4C and protruding to the lower side Z2 along the
central axis 17 is arranged on the bottom wall 4B. The supporting
shaft 20 is inserted into the through hole 3D on the bottom wall 3B
of the outer tank 3, and a lower end of the supporting shaft 20 is
located in the lower side Z2 of the bottom wall 3B.
[0075] The rotary wing 5, i.e. so-called impeller, is formed in a
discoid shape by taking the central axis 17 as a circle center, and
is concentrically arranged with the dewatering tank 4 along the
bottom wall 4B in the dewatering tank 4. A plurality of blades 5A
radially configured are arranged on an upper surface of the rotary
ring 5 facing the entrance 18 of the dewatering tank 4 from the
lower side Z2. A rotating shaft 21 extending toward the lower side
Z2 from a circle center of the rotary wing 5 along the central axis
17 is arranged on the rotary wing 5. The rotating shaft 21 is
inserted into a hollow part of the supporting shaft 20, and a lower
end of the rotating shaft 21 is located in the lower side Z2 of the
bottom wall 3B of the outer tank 3.
[0076] In the present embodiment, the motor 6 is realized through a
variable frequency motor. The motor 6 is arranged in the lower side
Z2 of the outer tank 3 in the housing 2, and is provided with an
output shaft 22 rotating by centering the central axis 17. The
transmission mechanism 7 is located between the lower ends of both
the supporting shaft 20 and the rotating shaft 21, and an upper end
of the output shaft 22. The transmission mechanism 7 selectively
transmits a driving force outputted by the motor 6 from the output
shaft 22 to one or both of the supporting shaft 20 and the rotating
shaft 21. A widely known transmission mechanism can be taken as the
transmission mechanism 7.
[0077] The dewatering tank 4 and the rotary wing 5 rotates around
the central axis 17 when the driving force from the motor 6 is
transmitted to the supporting shaft 20 and the rotating shaft 21.
The washings Q in the dewatering tank 4 are stirred through the
rotating dewatering tank 4 and the blades 5A of the rotary wing 5
during a washing operation and a rinsing operation. In addition, a
centrifugal force acts on the washings Q in the dewatering tank 4
through high-speed integrated rotation of the dewatering tank 4 and
the rotary wing 5 during a dewatering operation after the rinsing
operation. Thus, the washings Q are dewatered. A rotation direction
of the dewatering tank 4 and the rotary wing 5 is consistent with a
circumferential direction X of the dewatering tank 4.
[0078] FIG. 2 is a block diagram illustrating an electric structure
of the dewatering machine 1.
[0079] By referring to FIG. 2, the dewatering machine 1 includes: a
dewatering preparation unit, an information value acquisition unit,
a counting unit, a calculation unit, a determination unit, a
stopping unit, an information correction unit, an execution unit,
an acceleration unit, a duty ratio acquisition unit, a conversion
unit, a threshold changing unit, a threshold correction unit and a
control part 30 served as a suspending unit. The control part 30 is
configured as a microcomputer including: for example, CPU 31;
memory 32 such as a ROM, a RAM; a timer 33; and as a counter 34
served as the counting unit, and the control part 30 is internally
placed in the housing 2 (referring to FIG. 1).
[0080] The dewatering machine 1 further includes: a water level
sensor 35, a safety switch 36 as a detection unit, and a rotating
speed reading apparatus 37. The water level sensor 35, the safety
switch 36, the rotating speed reading apparatus 37, the motor 6,
the transmission mechanism 7, the feeding valve 14, the drainage
valve 16 and the operation part 10 are electrically connected with
the control part 30 respectively.
[0081] The control part 30 switches a transmission target of the
driving force of the motor 6 to one or both of the supporting shaft
20 and the rotating shaft 21 by controlling the transmission
mechanism 7. The control part 30 controls opening and closing of
the feeding valve 14 and the drainage valve 16. As mentioned above,
when the user selects the dewatering condition and the like of the
washings Q by operating the operating part 10, the control part 30
receives the selection.
[0082] The water level sensor 35 is a sensor for detecting the
water level of the outer tank 3 and the dewatering tank 4, and a
detection result of the water level sensor 35 is inputted into the
control part 30 in real time.
[0083] The safety switch 36 is a switch for detecting a vibration
of the outer tank caused by an eccentric rotation of the dewatering
tank 4 along with bias of the washings Q in the dewatering tank 4,
and is arranged at a position away from the outer tank 3 by a
specified interval along the horizontal direction HD in the housing
2 (referring to FIG. 1). When the outer tank 3 is caused to vibrate
along the horizontal direction HD substantially due to the
eccentric rotation of the dewatering tank 4 along with the bias of
the washings Q in the dewatering tank 4, the outer tank 3 comes
into contact with the safety switch 36 in forward and transverse
directions. Thus, the safety switch 36 is changed into "on", so as
to detect the vibration of the outer tank 3 mechanically, namely,
the eccentric rotation of the dewatering tank 4. The detection
result of the safety switch 36 is inputted into the control part 30
in real time.
[0084] The rotating speed reading apparatus 37 is an apparatus for
reading a rotating speed of the motor 6, and more specifically, is
an apparatus for reading a rotating speed of the output shaft 22 of
the motor 6, and consists of for example a plurality of Hall IC40.
The rotating speed read by the rotating speed reading apparatus 37
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, so that the motor 6
rotates with a desired rotating speed. On the other hand, the
control part 30 applies a brake to the rotation of the motor 6 to
stop the rotation of the dewatering tank 4 based on a fact that the
eccentric rotation of the dewatering tank 4 is detected by the
safety switch 36. The braker herein can cause a control part 30 to
control the duty ratio to stop the rotation of the motor 6
urgently, and also can cause the control part 30 to start a brake
device by additionally arranging the brake device (not shown),
thereby stopping the rotation of the motor 6 urgently.
[0085] For example, the number of Hall IC40 is 3 in the present
embodiment. The Hall IC40 are divided into a first Hall IC41, a
second Hall IC42 and a third Hall IC43. Herein, the motor 6 has a
rotor (not shown) integrally rotating with the output shaft 22, and
magnets in a N-pole and magnets in a S-pole are arranged
alternately in rows in a rotation direction of the rotor on an
external circumferential surface of the rotor. If a group
consisting of adjacent magnets in the N-pole and magnets in the
S-pole are called as a "NS group", a plurality of NS groups are
arranged along the rotation direction side by side on the external
circumferential surface of the rotor. The first Hall IC41, the
second Hall IC42, and the third Hall IC43 are arranged along the
rotation direction of the rotor at regular intervals side by side
according to such sequence. As the rotor rotates, each NS group
passes through each Hall IC40 along the rotation direction in
sequence. When the NS group passes through, each Hall IC40
transmits a pulse P. The rotating speed reading apparatus 37 reads
the rotating speed of the motor 6 through a size of an interval of
the adjacent pulses P.
[0086] FIG. 3 is a sequence diagram illustrating a state of an
output signal of the Hall IC40 forming the rotating speed reading
apparatus 37. In the sequence diagram of FIG. 3, a horizontal axis
indicates an elapsed time, and a vertical axis indicates an "on"
and "off" state of the output signal of each Hall IC. As shown in
FIG. 3, there exists a deviation between times that the first Hall
IC41, the second Hall IC42 and the third Hall IC43 produce the
pulse P. Therefore, when a certain NS group passes through each
Hall IC40 in sequence, the first Hall IC41, the second Hall IC42
and the third Hall IC43 produce the pulses P respectively according
to such sequence.
[0087] An "on" state indicating a state in which the pulse P is
produced and an "off" state other than the "on" state are presented
in a waveform of an output signal of each Hall IC40. "Interruption
W" is defined as switching from the "off" state to the "on" state
and switching from the "on" state to the "off" state. The
interruption W has a time at which the pulse P is produced and a
time at which the pulse P is disappeared twice in one pulse P. When
the interruption W occurs, the object of such situation is to input
from the rotating speed reading apparatus 37 to the control part 30
in real time. It shall be noted that, the times that the rotor 1 of
the motor 6 produces the interruption W during rotation are
different due to number of poles of the motor 6.
[0088] As shown in FIG. 3, when there are three Hall IC40 like in
the present embodiment, for example, in a period R of the first
Hall IC41 from the time at which the pulse P1 disappears to a time
at which the next pulse P2 is produced and then disappears, the
three Hall IC40 produce six interruptions W in total. With respect
to the entire three Hall IC 40, it is desired that an interval I
from some interruption W to the next interruption W is always the
same in a steady rotation state of the motor 6.
[0089] However, the interval I may also be disordered even if the
motor 6 rotates steadily, due to an installation error of the NS
group of the motor 6 and an installation error of each Hall IC40.
It shall be noted that, generally, the interval I is slowly
decreased when the motor 6 is in an acceleration state. The
interval I can be a value which is the same as a time unit (such as
second), and can also be a summing value of counts in each interval
I when the counter 34 (referring to FIG. 2) counts once according
to a fixed period.
[0090] Then, description is made to the dewatering operation
conducted in the dewatering machine 1.
[0091] FIG. 4 is a sequence diagram illustrating a state of a
rotating speed of the motor 6 in the dewatering operation process.
In the sequence diagram of FIG. 4, a horizontal axis indicates the
elapsed time, and a vertical axis indicates a rotating speed of the
motor 6 (unit: rpm). It shall be noted that, the rotating speed of
the dewatering tank 4 is the same as that of the motor 6 during the
dewatering operation.
[0092] By referring to FIG. 4, at the beginning of the dewatering
operation, a preparation stage, i.e., a dewatering preparation
interval, of the washings Q is provided. In the dewatering
preparation interval, the control part 30 adjusts a position
relationship between the washings Q in the dewatering tank 4 and
liquid in the balancing ring 19. After the dewatering preparation
interval, the control part 30 starts the rotation of the motor 6,
so as to dewater the washings Q.
[0093] Specifically, after the dewatering preparation interval, the
control part 30 causes the motor 6 to rotate steadily at 120 rpm
after the rotating speed of the motor 6 being increased from 0 rpm
to 120 rpm, i.e. a first rotating speed. The first rotating speed
is greater than a rotating speed (such as 50 rpm.about.60 rpm) at
which a transverse resonance occurred on the dewatering tank 4, and
is smaller than a rotating speed (such as 200 rpm.about.220 rpm) at
which a longitudinal resonance occurred on the dewatering tank 4.
After the motor 6 rotates at 120 rpm steadily, the control part 30
causes the motor 6 to rotate steadily at 240 rpm after the rotating
speed of the motor 6 being increased from 120 rpm to 240 rpm, i.e.
a second rotating speed. The second rotating speed is slightly
greater than the rotating speed at which the longitudinal resonance
is occurred. Next, the control part 30 causes the motor 6 to rotate
steadily at 800 rpm after the rotating speed of the motor 6 being
increased from 240 rpm to 800 rpm, i.e. a target rotating speed.
The washings Q in the dewatering tank 4 are formally dewatered
through the steady rotation of the motor 6 at 800 rpm.
[0094] In this way, the control part 30 causes the motor 6 to
accelerate through three stages i.e., a first acceleration stage of
enabling the motor 6 to rotate to 120 rpm from the beginning, a
second acceleration stage of rotating from 120 rpm to 240 rpm, and
a third acceleration stage of rotating from 240 rpm to 800 rpm, so
as to reach a target 800 rpm. Different from such situation, if the
motor 6 is accelerated to 800 rpm from 0 rpm uninterruptedly, a
drainage state of the drainage pipeline 15 may be deteriorated
since a lot of water leaks from the washings Q, or the drainage
pipeline 15 is jammed with foam. However, in the present
embodiment, the motor 6 is accelerated stepwise so that a lot of
water will not leak from the washings Q at one time. Therefore,
such bad condition can be prevented.
[0095] When the washings Q in the dewatering tank 4 are in a bias
configuration state of being distributed on the circumferential
direction X (referring to FIG. 1) of the dewatering tank 4
unevenly, the washings Q are biased in the dewatering tank 4. If
the dewatering operation is carried out in such state, the
dewatering tank 4 may be substantially shaken due to the eccentric
rotation thereof, thereby applying great vibration to the
dewatering machine 1, producing noise.
[0096] Therefore, the control part 30 detects whether the washings
Q in the dewatering tank 4 are biased during the dewatering
operation, and stops the motor 6 when detecting that the washings Q
are biased. The control part 30 performs four electric detections,
i.e. detection 1, detection 2, detection 3 and detection 4, in such
detection mode. It shall be noted that, the mechanical detection of
the safety switch 36 (referring to FIG. 1) is performed in the
whole period of the dewatering operation. It shall be noted that,
the term "detection" below refers to an action of inspecting, and
the term "check" refers to an action of finding some result during
the detection.
[0097] Detection 1 is performed at the first acceleration stage.
Detection 2 is performed at the second acceleration stage.
Detection 3 and detection 4 are performed at the third acceleration
stage. Specifically, detection 1 to detection 3 are performed in
the whole period of the corresponding acceleration stages in the
first acceleration stage to the third acceleration stage, and
relative to this, detection 4 is performed in a midway of the third
acceleration stage. In this way, the motor 6 is accelerated in
three stages in the dewatering machine 1, thereby monitoring a
rotation state of the dewatering tank 4 through detections 1-4
while avoiding performing the dewatering slowly at the rotating
speeds at which the transverse resonance and the longitudinal
resonance occurred, namely, 120 rpm and 240 rpm. Description is
made to the dewatering preparation stage and detections 1-4 in
sequence below.
[0098] Firstly, description is made to the dewatering preparation
stage. FIG. 5 is a schematic diagram illustrating an interior of
the dewatering tank 4. FIG. 5 shows an interior of the dewatering
tank 4 viewed along a direction of the central axis 17 of the
dewatering tank 4. A front position biasing toward the front side
Y1 and a deep position biasing toward the rear side Y2 are
presented in the dewatering tank 4. Since the central axis 17 is
arranged obliquely towards the front side Y1 relative to the
up-down direction Z, the front position is located at a position
closer to the lower side Z1 than the deep position (referring to
FIG. 1). Since the liquid accommodated in the balancing ring 19 is
free of the effect of the centrifugal force generated by the
rotation of the dewatering tank 4 in a state that the dewatering
tank 4 is static and that the dewatering tank 4 rotates at a very
low speed, the liquid accommodated in the balancing ring 19 is
provided at the front position in the balancing ring 19 due to a
self-weight and biased towards the lower side Z2.
[0099] In the case that the washings Q are placed in the dewatering
tank 4 in a manner of being biased along the circumferential
direction X, when the dewatering tank 4 starts to rotate, relative
to the central axis 17, the washings Q are preferably located at
the deep position at a side opposite to the liquid biased to the
front position in the lower side Z2 in the balancing ring 19. If
the washings Q are in such state, the eccentric rotation of the
dewatering tank 4 can be inhibited from the beginning of the
rotation since the dewatering tank 4 starts to rotate in a state
that the washings Q and the liquid in the balancing ring 19 are
roughly balanced.
[0100] In contrast, it is assumed that, in the dewatering tank 4,
the washings Q are biased in the circumferential direction X of the
dewatering tank 4 at a position same as the position where the
liquid in the balancing ring 19 is biased towards the lower side
Z2. In the state, when the dewatering tank 4 starts to rotate to
dewater the washings Q, the dewatering tank 4 carries out the
eccentric rotation when starting to rotate.
[0101] FIG. 6 is a sequence diagram illustrating a state of the
rotating speed of the motor 6 at the preparation stage of
dewatering operation. In the sequence diagram of FIG. 6, a
horizontal axis indicates the elapsed time, and a vertical axis
indicates the rotating speed of the motor 6 (unit: rpm). The
dewatering tank 4 rotates steadily at a very low speed at the
preparation stage. It shall be noted that, the rotating speed of
the motor 6 at this time is lower than a minimum rotating speed
when a resonance occurred on the dewatering tank 4. The minimum
rotating speed is different due to different sizes of the
dewatering tank 4, and is a rotating speed when the transverse
resonance occurred on the dewatering tank 4 in the present
embodiment, namely, 50 rpm-60 rpm described above. In this case,
for example, the rotating speed of the motor 6 at the preparation
stage is 10 rpm-30 rpm, preferably 20 rpm.
[0102] If the dewatering tank 4 rotates steadily at the very low
speed when the washings Q are placed in the dewatering tank 4 in a
manner of being biased in the circumferential direction X, the
rotating speed of the motor 6 is changed like that shown in FIG. 6.
Specifically, the washings Q are moved toward the upper side Z1
when going to the deep position from the front position, which
causes a burden to the motor 6. Therefore, the rotating speed of
the motor 6 is reduced. On the contrary, the rotating speed of the
motor 6 is increased due to the reduction of the previous burden
when the washings Q are moved to the front position from the deep
position. Therefore, it can be known that, the washings Q are
located at the front position when the rotating speed of the motor
6 is maximum, and the washings Q are located at the deep position
when the rotating speed of the motor 6 is minimum. In this way,
since the dewatering tank 4 rotates at very low speed, a biased
position of the washings Q in the dewatering tank 4 in the
circumferential direction X can be detected according to the
rotating speed of the motor 6.
[0103] FIG. 7 is a flow chart illustrating a control action at the
preparation stage of dewatering operation.
[0104] According to the above contents, the control part 30 causes
the motor 6 to start to rotate at very low speed at the dewatering
preparation stage, so that the dewatering tank 4 rotates at very
low speed (step S1). It shall be noted that, prior to the
dewatering operation, if the water in the outer tank 3 and the
dewatering tank 4 is discharged after the washings Q are rinsed,
the motor 6 starts to rotate at the very speed in step S1 according
to a current station that the discharging is finished. When the
motor 6 rotates at the very low speed, the control part 30 detects
the biased position of the washings Q in the dewatering tank 4 in
real time according to an output result from the rotating speed
reading apparatus 37 (step S2). Next, the control part 30 brakes
the motor to stop the rotation of dewatering tank 4 immediately
before the washings Q reach at the deep position according to the
detected biased position (step S3).
[0105] If the rotation of the dewatering tank 4 is stopped when the
washings Q biased in the dewatering tank 4 are located at a side
opposite to the liquid in the balancing ring 19 relative to the
central axis 17, the washings Q will finally arrive at a side same
as that of the liquid in the balancing ring 19 because the rotation
might not be stopped timely or the dewatering tank 4 might rotate
again due to inertia when the brake is relieved after the
dewatering tank 4 is stopped.
[0106] In view of this, the control part 30 causes the dewatering
tank 4 to stop rotating immediately before the washings Q biased in
the dewatering tank 4 is located at a side opposite to, relative to
the central axis 17, the liquid biased towards the lower side Z2 in
the balancing ring 19. Therefore, after the dewatering tank 4 is
stopped, the washings Q biased in the dewatering tank 4 and the
liquid biased towards the lower side Z2 in the balancing ring 19
are maintained at a state of being located at roughly opposite
sides relative to the central axis 17. In addition, since the
dewatering tank 4 is supported through a one-way bearing in a
unidirectional rotation manner, the stopped dewatering tank 4 does
not reverse, and is in a static state. After such preparation
stage, when the dewatering tank 4 rotates to dewater, the
dewatering tank 4 rotates in a state that the liquid in the
balancing ring 19 and the washings Q are roughly balanced. Thus,
the eccentric rotation of the biased dewatering tank 4 can be
inhibited early.
[0107] Next, description is made to the first acceleration stage
after subjecting to the dewatering preparation interval. It shall
be noted that, since the liquid in the balancing ring 19 is not
biased toward the lower side Z2 due to an effect of the centrifugal
force after the first acceleration stage, the liquid substantively
does not cause the eccentric rotation of the dewatering tank 4.
[0108] FIG. 8 is a flow chart illustrating a control action in the
first acceleration stage. By referring to FIG. 8, after the
dewatering preparation interval, the control part 30 causes the
motor 6 to accelerate to reach a target rotating speed (i.e., 120
rpm) so as to start the dewatering operation (step S11). Once the
above interruption W is inputted ("yes" in step S12), the control
part 30 enables a count value n with an initial value "zero" to add
by 1 (+1) (step S13). Then, the control part 30 starts detection 1
in the first acceleration stage (step S14). When detection 1 is
"OK" ("yes" in step S15), that is, under a condition that the
control part 30 determines that the washings Q are not biased, the
control part 30 resets the count value n to zero (step S17) if
detection 1 is ended ("yes" in step S16). Then, when the rotating
speed of the motor 6 reaches 120 rpm ("yes" in step S18), the
control part 30 causes the motor 6 to rotate steadily at 120 rpm
(step S19).
[0109] FIG. 9A and FIG. 9B are flow charts illustrating a control
action regarding detection 1. By referring to FIG. 9A, the control
part 30 starts detection 1 in the above step S14, and once the
interruption W is inputted ("yes" in step S21), a timing value
A.sub.n is obtained (step S22). The timing value A.sub.n is
referred to as A.sub.n below. A.sub.n is the interval I between the
inputted interruption W and the previous interruption W (referring
to FIG. 3) and is a positive value measured by the timer 33. Under
a condition that there does not exist a previous interruption W,
the interval I from a start time of detection 1 to the initial
interruption W is A.sub.n. It shall be noted that, when the
interruption W is inputted, since the count value n is added by 1
(step S13) while A.sub.n is obtained, a suffix "n" in the A.sub.n
is consistent with the count value n added by 1. Therefore, for
example, when the initial interruption W is inputted, the count
value n becomes 1, and A.sub.n becomes A.sub.1. When a next
interruption W is inputted, the count value n becomes 2, and
A.sub.n becomes A.sub.2.
[0110] Next, the control part 30 calculates a moving average value
B.sub.n of A.sub.n (step S23). Hereinafter, the moving average
value B.sub.n is sometimes referred to as B.sub.n. B.sub.n is a
value obtained by dividing a summing value of A.sub.n and previous
A.sub.n-1.about.A.sub.n-5 by 6. Herein, 6 is divided so as to be in
combination with the situation that there exists six interruptions
W during the period R from the time that the pulse P disappears to
the time that the next pulse P is produced and then disappears
(referring to FIG. 3).
[0111] Next, the control part 30 calculates a moving average value
C.sub.n of B.sub.n (step S24). Hereinafter, the moving average
value C.sub.n is sometimes referred to as C.sub.n. C.sub.n is a
value obtained by dividing a summing value of B.sub.n and previous
B.sub.n-1.about.B.sub.n-5 by 6.
[0112] In an acceleration state of the motor 6 for accelerating to
the target rotating speed, the control part 30 enables the count
value n to be added by 1 in step S13 (referring to FIG. 8) once the
interruption W is inputted, and obtains C.sub.n successively in
step S24. Therefore, in fact, the operation for adding the count
value n by 1 and the operation for obtaining C.sub.n are conducted
simultaneously. That is, the control part 30 enables the count
value n to be added by 1 every time C.sub.n is obtained.
[0113] According to experiences, the obtained A.sub.n.about.C.sub.n
are not stable until the count value n reaches a specified starting
value ("no" in step S25), and the count value n is inapplicable to
detection 1. The starting value refers to, such as, 75, in the
present embodiment. When the count value n reaches the starting
value ("yes" in step S25), the control part 30 calculates a
difference D.sub.n obtained by subtracting the previous C.sub.n-1
from C.sub.n (step S26). Then, the control part 30 calculates a
moving average value E.sub.n of the difference D.sub.n (step S27).
The moving average value E.sub.n is a value obtained by dividing a
summing value of the difference D.sub.n and previous differences
D.sub.n-1.about.D.sub.n-5 by 6. Hereinafter, the difference D.sub.n
is referred to as D.sub.n and the moving average value E.sub.n is
referred to as E.sub.n.
[0114] With respect to respective meanings of D.sub.n and E.sub.n,
description is made by taking C.sub.11
(=(B.sub.6+B.sub.7+B.sub.8+B.sub.9+B.sub.10+B.sub.11)/6) and
C.sub.17
(=(B.sub.12+B.sub.13+B.sub.14+B.sub.15+B.sub.16+B.sub.17)/6) as an
example. E.sub.17, the count value n of which is consistent with
that of C.sub.17, is a value obtained by dividing
D.sub.12.about.D.sub.17 by 6. E.sub.17 may be expressed with
C.sub.n as shown in the following formula (1), and may be expressed
with B.sub.n as shown in the following formula (2).
E 17 = ( D 12 + D 13 + D 14 + D 15 + D 16 + D 17 ) / 6 = ( C 12 - C
11 + C 13 - C 12 + C 14 - C 13 + C 15 - C 14 + C 16 - C 15 + C 17 -
C 16 ) / 6 = ( C 17 - C 11 ) / 6 Formula ( 1 ) E 17 = ( ( B 12 + B
13 + B 14 + B 15 + B 16 + B 17 ) - ( B 6 + B 7 + B 8 + B 9 + B 10 +
B 11 ) ) / 36 Formula ( 2 ) ##EQU00001##
[0115] As mentioned above, with respect to the total three Hall
IC40, there exists six interruptions W during the period R of one
Hall IC40 from the time at which a pulse P disappears to the time
at which the next pulse P is produced and then disappears
(referring to FIG. 3). The installation error of the Hall IC40 can
be eliminated through B.sub.n. Moreover, according to Formula (2),
E.sub.n is equivalent to a difference of a summing value of
B.sub.n.about.B.sub.n+5 related to six interruptions W produced
when a certain NS group passes one Hall IC40 and a summing value of
B.sub.n+6.about.B.sub.n+11 related to six interruptions W produced
when a next NS group passes the Hall IC40. An error due to a
relevant position of the adjacent NS groups can be roughly
eliminated through E.sub.n calculated with multiple B.sub.n.
[0116] FIG. 10 is a diagram illustrating a relationship between a
count value n and C.sub.n, where a horizontal axis indicates the
count value n, and a vertical axis indicates C.sub.n. By referring
to FIG. 10, although A.sub.n decreases with a rotating speed
increase caused by the acceleration of the motor 6, the change of
A.sub.n is disordered due to the installation error of the NS group
and the installation error of each Hall IC40. The actual A.sub.n
increases and decreases as shown by the dotted line. B.sub.n is
obtained through the moving average in S23 with the installation
error of each Hall IC40 being eliminated, and C.sub.n is obtained
through the moving average in S24 with the noise of B.sub.n being
eliminated. Then, D.sub.n is obtained through C.sub.n, and E.sub.n
is obtained through D.sub.n. A.sub.n, B.sub.n, C.sub.n, D.sub.n and
E.sub.n are relevant information values regarding the rotation
state of the motor 6.
[0117] In the case that the dewatering tank 4 does not rotate
eccentrically because the washings Q are not biased, C.sub.n should
decrease with the increase of the rotating speed of the motor 6
(referring to an arrow in a dot and dash line), as shown by a solid
line in FIG. 10. In addition, since the moving average value of
A.sub.n is B.sub.n and the moving average value of B.sub.n is
C.sub.n, A.sub.n and B.sub.n should also decrease with the increase
of the rotating speed of the motor 6 although both of A.sub.n and
B.sub.n have noise respectively.
[0118] In the case that the dewatering tank 4 does not rotate
eccentrically, since C.sub.n always decreases in the acceleration
process of the motor 6, the difference D.sub.n obtained by
subtracting the previous C.sub.n-1 from C.sub.n becomes not greater
than zero, and the moving average value E.sub.n of D.sub.n also
becomes not greater than zero. By referring to FIG. 9B, if E.sub.n
is not greater than zero ("yes" in step S28), the control part 30
enables a variable F.sub.n to be zero (step S29). On the other
hand, in the case that the dewatering tank 4 rotates eccentrically
because the washings Q in the dewatering tank 4 are biased, C.sub.n
which should decrease may be changed and increase with the increase
of the rotating speed of the motor 6. In this case, D.sub.n and
E.sub.n at a time, at which C.sub.n increased, become greater than
zero ("no" in step S28), and the control part 30 sets the variable
F.sub.n as E.sub.n per se (step S30).
[0119] The control part 30 calculates an accumulated value G
(=F.sub.1+F.sub.2+ . . . ) of F.sub.n once F.sub.n is obtained
(step S31). The accumulated value G is also an accumulated value of
the moving average value E.sub.n of the difference D.sub.n between
C.sub.n and C.sub.n-1 in the case that C.sub.n is greater than the
previous C.sub.n-1.
[0120] FIG. 11 is a diagram illustrating a relationship between the
count value n and the accumulated value G, where a horizontal axis
indicates the count value n, and a vertical axis indicates the
accumulated value G. In the case that the motor 6 accelerates while
the dewatering tank 4 eccentrically rotates continuously, the
accumulated value G increases stepwise, as shown in FIG. 11. With
respect to the accumulated value G, first thresholds are determined
according to each specified count value n. The first thresholds are
correlated with the count value n and stored in the memory 32
(referring to FIG. 2). The first thresholds are positive
values.
[0121] Returning to FIG. 9B, when the accumulated value G for count
value n with a specified value reaches a first threshold for count
value n with the specified value ("yes" in step S32), the control
part 30 sets the detection result as NG, and determines that the
dewatering tank 4 is largely eccentric and the washings Q are
biased (step S33).
[0122] On the other hand, if the accumulated value G is less than
the corresponding first threshold ("no" in step S32), the control
part 30 sets the detection result as OK, and determines that the
washings Q are not biased (step S34). Then, the control part 30
carries out steps S21.about.S34 repeatedly, until the count value n
becomes an end value indicating that the first acceleration stage
is ended ("no" in step S35). The end value of the count value n in
the present embodiment is, for example, 245. When the count value n
becomes the end value ("yes" in step S35), detection 1 is ended by
the control part 30 (step S36). The processes of steps
S21.about.S34 are equivalent to the process of the above step S15,
and the processes of steps S35.about.S36 are equivalent to the
process of the above step S16 (referring to FIG. 8).
[0123] FIG. 12 is a flow chart illustrating a control action in the
case that the detection result is NG. By referring to FIG. 12, the
control part 30 causes the motor 6 to stop rotating (step S41),
i.e. causes the dewatering tank 4 to stop rotating, when the
detection result is determined as NG. Thus, in the case that the
washings Q in the dewatering tank 4 are biased, the eccentric
rotation of the dewatering tank 4 can be inhibited early when the
motor 6 is in the acceleration state.
[0124] Especially, prior to calculating the accumulated value G,
the control part 30 first corrects a calculation basis (i.e.,
A.sub.n) of the accumulated value G through performing the moving
average in step S23 and step S24 repeatedly. Therefore, C.sub.n
obtained as a correction result becomes a high precision value with
the error being eliminated. Therefore, an accumulated value G with
high precision is calculated according to C.sub.n, the precision of
which is improved through the correction, and the bias of the
washings Q is detected with high precision through the accumulated
value G, thus the eccentric rotation of the dewatering tank 4 can
be inhibited early.
[0125] After the dewatering tank 4 stops rotating, the control part
30 determines whether the current state is a state before the
dewatering operation is restarted (step S42). Restarting of the
dewatering operation refers to a restarting process, through which
the control part 30 starts the dewatering operation again by
enabling the dewatering tank 4 to rotate again immediately after
the dewatering tank 4 is caused to stop rotating to suspend the
dewatering operation. Sometimes, the restarting process may also be
conducted even if the biasing of the washings Q is small.
[0126] Before the restarting of the restarting process is
implemented ("yes" in step S42), the control part 30 performs the
restarting process (step S43). It shall be noted that, prior to the
restarting process, a drainage can be first conducted in the outer
tank 3. In the case that the drainage pipeline 15 is jammed with
foams, the foams can be discharged outside of the drainage pipeline
15 through the drainage herein, and thus, the situation that the
drainage pipeline 15 is jammed with the foams can be
eliminated.
[0127] If it is not a state before restarting ("no" in step S42),
the control part 30 performs a correction process (step S44). In
the correction process, the control part 30 closes the drainage
valve 16 and opens the feeding valve 14 so as to feed water into
the dewatering tank 4 to a specified water level, so that the
washings Q in the dewatering tank 4 are immerged into water and are
easy to loosen. In this state, the control part 30 causes the
washings Q attached to the internal circumferential surface of the
dewatering tank 4 to peel off and stir by causing the dewatering
tank 4 and the rotary wing 5 to rotate, thereby correcting the
biasing of the washings Q in the dewatering tank 4.
[0128] In this way, the control part 30 performs either the
restarting process or the correction process alternatively in the
case that the dewatering tank 4 has stopped rotating. If the
biasing of the washings Q is small enough so that the dewatering
tank 4 does not rotate eccentrically, the dewatering is started
again through the restarting process. Therefore, a time required in
the whole dewatering process can be shortened as far as possible.
If the biasing of the washings Q is large enough so that the
dewatering tank 4 rotates eccentrically again in the next
dewatering process, the biasing of the washings Q can be reliably
corrected through the correction process.
[0129] After performing the restarting process for a specified
number (which is 1 herein) and enabling the dewatering tank 4 to
stop rotating ("no" in step S42), the control part 30 selects to
not perform the restarting process and selects to perform the
correction process (step S44). That is, in the case that the
restarting process has been performed for the specified number and
the dewatering tank 4 has stopped rotating, the biasing of the
washings Q is large and needs to be corrected. In this case, the
correction process is quickly performed rather than spending time
on the restarting process and stopping the rotation of the
dewatering tank 4. Therefore, the biasing is corrected reliably.
Therefore, the eccentric rotation of the dewatering tank 4 can be
inhibited early. It shall be noted that, in the present embodiment,
although the specified time is set as 1, it can also be set as more
than 2.
[0130] Then, description is made to the second acceleration stage
after the steady rotation at 120 rpm. FIG. 13 is a flow chart
illustrating a control action in the third acceleration stage. By
referring to FIG. 13, the control part 30 causes the motor 6 to
accelerate to a target rotation speed of 240 rpm at the second
acceleration stage (step S51). The control part 30 enables the
count value n to add by 1 (step S53) once the interruption W is
inputted ("yes" in step S52). It shall be noted that, the count
value n at the beginning of the second acceleration stage is
zero.
[0131] Next, in the second acceleration stage, the control part 30
starts detection 2 (step S54). In the case that detection 2 is OK
("yes" in step S55), that is, in the case that the control part 30
determines that the washings Q are not biased in the second
acceleration stage, the control part 30 resets the count value n to
zero (step S57) at the end of detection 2 ("yes" in step S56).
Then, when the rotating speed of the motor 6 reaches 240 rpm ("yes"
in step S58), the control part 30 causes the motor 6 to rotate
steadily at 240 rpm (step S59).
[0132] The content of detection 2 is the same as that of detection
1. Therefore, the processes of above steps S21.about.S34 are
equivalent to the process of step S55, and the processes of step
S35 and S36 are equivalent to the process of step S56 (referring to
FIG. 9B). The first threshold in detection 2 is set as to be
different from that in detection 1. In addition, with respect to
detection 2, since the rotating speed of the motor 6 is higher than
that in detection 1, the starting value in step S25 (referring to
FIG. 9A) is accordingly less than the starting value in detection
1, which is, for example, 17 in the present embodiment. In the case
that the detection result of detection 2 is NG ("no" in step S55),
that is, in the case that the control part 30 determines that the
washings Q in the dewatering tank 4 are biased, the control part 30
performs the processes of steps S41.about.S44 as it did in
detection 1 (referring to FIG. 12).
[0133] It shall be noted that, with respect to the dewatering
operation under the restarting process after detection 2, the
duration of the steady rotation at 120 rpm (referring to FIG. 4)
can be shortened to be shorter than the duration of the steady
rotation at 120 rpm of the previous dewatering operation which is
stopped. With respect to the restarting process, since the washings
Q are attached to the internal circumferential surface of the
dewatering tank 4 to a certain extent and in a state of roughly
being dewatered, the duration of the steady rotation at 120 rpm can
be shortened. Thus, the time of the dewatering operation can be
shortened.
[0134] Next, description is made to the third acceleration stage
after the steady rotation at 240 rpm. FIG. 14 is a flow chart
illustrating a control action in the third acceleration stage. By
referring to FIG. 14, the control part 30 causes the motor 6 to
accelerate to a target rotating speed 800 rpm in the third
acceleration stage (step S61). The control part 30 enables the
count value n to be added by 1 (step S63) once the interruption W
is inputted ("yes" in step S62). In addition, the count value n at
the beginning of the third acceleration stage is zero.
[0135] In the third acceleration stage, the control part 30 starts
detection 3 (step S64). Next, in the case that detection 3 is OK
("yes" in step S65), that is, in the case that the control part 30
determines that the washings Q are not biased, the control part 30
stops detection 3 when the rotating speed of the motor 6 reaches
800 rpm ("yes" in step S66), and resets the count value n as zero,
so that the motor 6 rotates steadily at 800 rpm to continue to
dewater (step S67).
[0136] The content of detection 3 is substantively the same as
those of detections 1 and 2. Therefore, the processes of the above
steps S21.about.S34 are equivalent to the process of step S65
(referring to FIG. 9A and FIG. 9B). The first threshold in
detection 3 is set as to be different from those of detections 1
and 2 respectively. It shall be noted that, the starting value in
step S25 (referring to FIG. 9A) in detection 3 is the same as that
in detection 2. In the case that the detection result of detection
3 is NG ("no" in step S65), that is, in the case that the control
part 30 determines that the washings Q in the dewatering tank 4 are
biased, the control part 30 also performs the processes of steps
S41.about.S44 as it does in detections 1 and 2 (referring to FIG.
12).
[0137] It shall be noted that, with respect to dewatering operation
under the restarting process after detection 3, as described
regarding detection 2, the duration of the steady rotation at 120
rpm may be shortened to be shorter than the duration of the steady
rotation at 120 rpm of the previous dewatering operation which is
stopped. Moreover, the difference between detection 3 and
detections 1, 2 lies in: after n becomes the end value in step S35
(referring to FIG. 9B), the processes in step S21.about.step S34
may also be repeated during the period that the rotating speed of
the motor 6 reaches 800 rpm. At the beginning of repeating such
processes, respective values of n and A.sub.n.about.G are reset to
zero.
[0138] As described above, in detection 1 of the first acceleration
stage, detection 2 of the second acceleration stage and detection 3
of the third acceleration stage, the control part 30 acquires
information values of A.sub.n.about.E.sub.n and the like
respectively, enables the count value to be added by 1 so as to
calculate the accumulated value G. When the accumulated value G
reaches a corresponding first threshold, the control part 30
determines that the washings Q are biased in the dewatering tank 4
and causes the dewatering tank 4 to stop rotating. That is, since
the detection of the biasing of the washings Q begins in the first
acceleration stage after the motor 6 starts to rotate, eccentric
rotation of the dewatering tank 4 may be inhibited early. Moreover,
since the detection of the biasing of the washings Q is carried out
in three stages in a sequence of the first acceleration stage, the
second acceleration stage, and the third acceleration stage, the
biasing of the washings Q can be reliably detected, so that
eccentric rotation of the dewatering tank 4 may be inhibited as
early as possible.
[0139] In detection 3, the control part 30 executes detection in a
first mode. As described above, In the detection in the first mode,
the biasing of the washings Q in the dewatering tank 4 is detected
according to whether the accumulated value G reaches the first
threshold. The control part 30 may also execute a detection in a
second mode rather than executing the detection in the first mode.
In the detection in the second mode, the biasing of the washings Q
is detected according to whether a variation of the accumulated
value G reaches a third threshold. Different from the first
threshold, the third threshold is preset and stored in the memory
32 (referring to FIG. 2). The third threshold is a positive value.
Like in the third acceleration stage, when the rotating speed of
the motor 6 rises to a certain extent, for example, 400 rpm, an
eccentric state of the washings Q in the dewatering tank 4 may be
deteriorated because water of the washings Q is removed due to
previous dewatering. As a result, the vibration of the dewatering
tank 4 becomes larger. On the other hand, as the characteristics of
the accumulated value G, although the accumulated value G sharply
increases when the rotating speed of the motor 6 is low, the
accumulated value G increases slowly as the rotating speed
approaches the target rotating speed.
[0140] Thus, merely for the detection in the first mode, when the
rotating speed rises to some extent, the accumulated value G may be
lower than the first threshold no matter whether the vibration of
the dewatering tank 4 is large or small, so that the dewatering
tank 4 fails to stop rotating. Accordingly, both of the detections
in the first mode and the second mode may be executed. As for the
detection in the second mode, when the variation of the accumulated
value G, i.e., a variation degree of the accumulated value G,
reaches the third threshold, the control part 30 determines that
the washings Q are biased and causes the dewatering tank 4 to stop
rotating. Thus, the accumulated value G may always be small and
fails to reach the first threshold no matter whether the dewatering
tank 4 is in a state of large amplitude vibration, and with such
situation, state variation of the washings Q during dewatering may
also be sensitively reflected by focusing on the variation of the
accumulated value G. Therefore, the eccentric rotation of the
dewatering tank 4 can be reliably inhibited early. Certainly, the
detection in the second mode not only can be executed in detection
3, but also can be executed in detection 1 and detection 2.
[0141] Next, description is made to detection 4 which is executed
in parallel with the detection 3 in the third acceleration stage.
Detection 4 consists of detection 4-1 and detection 4-2. Detections
1-3 are detections for detecting the biasing of the washings Q by
using interruption W related to the motor 6 in an acceleration
state. Relative to this, detection 4-1 and detection 4-2 are
detections for detecting the biasing of washings Q by using the
duty ratio. FIG. 15 is a flow chart illustrating schemas of
detection 4-1 and detection 4-2.
[0142] Referring to FIG. 15, as the third acceleration stage, the
control part 30 causes the motor 6 to accelerate from 240 rpm to
800 rpm in step S61 (referring to FIG. 14).
[0143] In a state that the motor 6 is accelerated, when the
rotating speed of the motor 6 reaches 300 rpm, the control part 30
acquires a duty ratio of the voltage applied to the motor 6 at this
moment as .alpha. value (step S71). The rotating speed 300 rpm does
not refer to a rotating speed in a state that water is stored in
the dewatering tank 4, but refers to a rotating speed which is not
influenced by eccentricity of the dewatering tank 4 most. Thus, the
.alpha. value at 300 rpm is the duty ratio in a state that it is
not influenced by eccentricity of the dewatering tank 4 most, but
only is influenced by a load of the washings Q.
[0144] Moreover, in a state that the motor 6 continues to
accelerate, during a period in which the rotating speed rises from
600 rpm to 729 rpm, the control part 30 implements detection 4-1
(step S72). Under a condition that detection 4-1 is not OK ("no" in
step S72), that is, under a condition that the control part 30
determines that the washings Q are biased, the control part 30
executes the processes in step S41.about.step S44 as it does in
detections 1.about.3 (referring to FIG. 12). It shall be noted
that, as described in detection 2 and detection 3, with respect to
the dewatering operation in the restarting process after detection
4-1, the duration of the steady rotation at 120 rpm may be
shortened to be shorter than the duration of the steady rotation at
120 rpm of the previous dewatering operation which is stopped.
[0145] On the other hand, under a condition that detection 4-1 is
OK ("yes" in step S72), that is, under a condition that the control
part 30 determines in detection 4-1 that the washings Q are not
biased, the control part 30 continues to implement detection 4-2 in
a state that the motor 6 continues to accelerate from 730 rpm (step
S77).
[0146] Under a condition that detection 4-2 is OK ("yes" in step
S77), that is, under a condition that the control part 30
determines in detection 4-2 that the washings Q are not biased, the
control part 30 causes the motor 6 to stably rotate at 800 rpm
after accelerating the motor 6 to the target rotating speed of 800
rpm, so as to cause the washings Q to be dewatered continuously
(step S78).
[0147] On the other hand, under a condition that detection 4-2 is
not OK ("no" in step S77), that is, under a condition that the
control part 30 determines that the washings Q are biased, the
control part 30 causes the motor 6 to stably rotate at a rotating
speed less than 800 rpm, so as to cause the washings Q to be
dewatered continuously (step S79).
[0148] Next, detection 4-1 and detection 4-2 are described in
detail respectively.
[0149] FIG. 16 is a flow chart illustrating a control action with
respect to detection 4-1. Referring to FIG. 16, in the state that
the motor 6 continues to accelerate after step S71 (referring to
FIG. 15), the control part 30 starts to carry out detection 4-1
(step S80) as the rotating speed of the motor 6 reaches 600
rpm.
[0150] Next, the control part 30 starts to count through the
counter 34 (step S81), and initializes the counter 34 every 0.3 s
so as to count within 0.3 s (step S82 and step S83).
[0151] The control part 30 acquires the rotating speed of the motor
6 at the time of each counting and a duty ratio d.sub.m(m: a count
value) of the voltage applied to the motor 6 at the time of
counting (step S84). That is, the control part 30 acquires the
rotating speed and the duty ratio d.sub.m of the motor 6 at
specified moment in the third acceleration stage in which the
rotating speed of the motor 6 rises from 240 rpm to 800 rpm. The
duty ratio d.sub.m is an information value related to the rotation
state of the motor 6.
[0152] Moreover, in step S84, the control part 30 calculates a
correction value B.sub.m according to the following formula (3),
where B.sub.m is obtained by correcting the duty ratio d.sub.m with
the .alpha. value. It shall be noted that X and Y in the formula
(3) are constants solved through experiments and the like.
Different from simple ratio calculation, a weight is changed
through the formula (3), so that the duty ratio d.sub.m is
corrected, and detection 4-1 may be executed with good accuracy
through the obtained correction value B.sub.m.
B.sub.m=d.sub.m-(.alpha..times.X+Y) formula (3)
[0153] Moreover, in step S84, the control part 30 calculates a
moving accumulated value C.sub.m (m: count value) of the correction
value B.sub.m. The moving accumulated value C.sub.m is a value
obtained by summing 5 consecutive correction values B.sub.m in a
counting sequence. Additionally, as for a certain moving
accumulated value C.sub.m and a moving accumulated value C.sub.m-1
previous to C.sub.m, the last 4 correction values B.sub.m among the
5 correction values B.sub.m for forming the moving accumulated
value C.sub.m-1 and the front 4 correction values B.sub.m among the
5 correction values B.sub.m for forming the moving accumulated
value C.sub.m are same values respectively. It shall be noted that
the number of the correction values B.sub.m for forming the moving
accumulated value C.sub.m is not limited to 5. The moving
accumulated value C.sub.m is a specified index value transformed
from the duty ratio d.sub.m by the control part 30.
[0154] Next, the control part 30 calculates a second threshold
(step S85) related to the moving accumulated value C.sub.m
according to the following formula (4). The second threshold is a
positive value.
The second threshold=(rotating speed).times.a+b formula (4)
[0155] a and b in the formula (4) are constants solved through
experiments and the like and stored in the memory 32. Moreover, the
constants a, b are different depending on the rotating speed of the
motor 6 at the current moment and a selected dewatering condition.
Thus, as for the second threshold herein, multiple values exist at
the same rotating speed. It shall be noted that the second
threshold is a value not influenced by the .alpha. value, and this
case is further defined through the formula (4).
[0156] Then, the control part 30 confirms whether the rotating
speed of the motor 6 at the current moment is less than 730 rpm
(step S86).
[0157] Under a condition that the rotating speed of the motor 6 at
the current moment is less than 730 rpm ("yes" in step S86), the
control part 30 determines whether a newest moving accumulated
value C.sub.m falls in the range of detection 4-1 (step S87).
[0158] FIG. 17 is a diagram illustrating a relationship between the
rotating speed and the moving accumulated value C.sub.m in
combination with detection 4-1 and detection 4-2. In FIG. 17, a
horizontal axis represents the rotating speed (unit: rpm), and a
longitudinal axis represents the moving accumulated value C.sub.m.
Referring to FIG. 17, the second thresholds calculated in step S85
are set to be two thresholds including an upper second threshold
represented by a dot dash line and a lower second threshold
represented by a double dot dash line. The upper second threshold
is higher than the lower second threshold. The upper second
threshold and the lower second threshold vary along with the
rotating speed.
[0159] As for the dewatering conditions, there exists the following
three dewatering conditions: carrying out the dewatering operation
after "water storage rinsing" of rinsing the washings Q with the
water stored in the dewatering tank 4; "water splashing and
dewatering" of carrying out the dewatering operation by draining
water when splashing the water to the washings Q; the above
"restarting process", etc. The dewatering conditions are selected
by the user through operating the operation part 10, and the
selection is received by the control part 30. In the dewatering
operation after washing operation and water storage rinsing, of the
motor 6 is hard to accelerate since the washings Q contain a great
quantity of water, while under the condition of water splashing and
dewatering and the restarting process, acceleration of the motor 6
may be realized with very tiny force because the water is removed
from the washings Q to some extent.
[0160] In the dewatering operation after the washing operation and
water storage rinsing, the control part 30 uses the upper second
threshold higher than the lower second threshold because it is
difficult to execute detection with the lower second threshold. On
the other hand, in the dewatering operation after water splashing
and dewatering and the restarting process, the control part 30 uses
the lower second threshold lower than the upper second threshold
because the detection is not accurate if the upper second threshold
is used. Thus, under either the condition that the washings Q
contain a great quantity of water or under the condition that the
water of the washings Q are removed to some extent, detection 4-1
is executed with the second threshold suitable for the respective
conditions.
[0161] Moreover, based on the objective same as a difference
between such dewatering conditions, under the condition that the
load of the washings Q in the dewatering tank 4 is large, the
control part 30 uses the upper second threshold higher than the
lower second threshold in detection 4-1 because it is difficult to
execute the detection with the lower second threshold. Moreover,
under the condition that the load of the washings Q in the
dewatering tank 4 is small, the control part 30 uses the lower
second threshold lower than the upper second threshold in detection
4-1 because the detection is not accurate if the upper second
threshold is used. Thus, detection 4-1 is executed with the second
threshold suitable for different loads of the washings Q
respectively.
[0162] It shall be noted that in FIG. 17, although the two second
thresholds including the upper second threshold and the lower
second threshold are illustrated, more than 3 second thresholds may
also be set according to various dewatering conditions and the
loads.
[0163] Moreover, compared with the condition that the washings Q
are not biased due to smaller eccentricity (referring to a solid
line in FIG. 17), under the condition that the washings Q are
biased due to larger eccentricity (referring to the dotted lines in
FIG. 17), the moving accumulated value C.sub.m at each rotating
speed is larger. If the washings Q are greatly biased, the moving
accumulated value C.sub.m is larger than the set second threshold,
i.e. a corresponding one of the upper second threshold and the
lower second threshold.
[0164] Returning to FIG. 16, when the newest moving accumulated
value C.sub.m reaches the second threshold for a corresponding
moment, the control part 30 determines that the washings Q are
biased in the dewatering tank 4 and the moving accumulated value
C.sub.m falls in the range of detection 4-1 ("yes" in step
S87).
[0165] When the control part 30 determines that the moving
accumulated value C.sub.m falls in the range of detection 4-1
("yes" in step S87), the processes in steps S41.about.S44 will be
executed (referring to FIG. 12). The processes in steps
S80.about.S87 are included in the above step S72 (referring to FIG.
15).
[0166] Next, if it is determined in detection 4-1 that the washings
Q are not biased, the control part 30 ends detection 4-1 and then
starts detection 4-2 (step S88) when the rotating speed of the
motor 6 reaches 730 rpm ("no" in step S86).
[0167] FIG. 18 is a flow chart illustrating a control action
regarding detection 4-2. Referring to FIG. 18, in the case that the
motor 6 continues to accelerate, the control part 30 starts
detection 4-2 (step S88) as the rotating speed of the motor 6
reaches 730 rpm.
[0168] Next, the control part 30 starts to count through the
counter 34 (step S89), and initializes the counter 34 per 0.3 s so
as to carry out counting within each 0.3 s (steps
S90.about.S91).
[0169] Similar to step S84 in detection 4-1, upon each counting,
the control part 30 acquires the rotating speed of the motor 6 at
the time of each counting and the duty ratio d.sub.m of the voltage
applied to the motor 6 at the time of counting, and calculates the
correction value B.sub.m and the moving accumulated value C.sub.m
(step S92).
[0170] Next, the control part 30 calculates the second threshold
(step S93) related to the moving accumulated value C.sub.m
according to the formula (4). The constants "a", "b" included in
the formula are same as those used in detection 4-1, and are
different depending on the rotating speed of the motor 6 at the
current moment and the selected dewatering condition. Therefore, at
the same rotating speed, the second threshold herein may have
multiple values like the upper second threshold and the lower
second threshold described above.
[0171] Next, the control part 30 confirms whether the rotating
speed of the motor 6 at the current moment reaches the target
rotating speed (800 rpm) (step S94).
[0172] In the case that the rotating speed of the motor 6 at the
current moment dos not reach the target rotating speed ("yes" in
step S94), the control part 30 determines whether the newest moving
accumulated value C.sub.m falls in the range of the detection 4-2
(step S95) as it does in detection 4-1 (step S87).
[0173] Specifically, by referring to FIG. 17, compared with the
situation that the washings Q are not biased due to small
eccentricity (referring to the solid line in FIG. 17), in the
situation that the washings Q are biased due to larger eccentricity
(referring to the dotted line in FIG. 17), the moving accumulated
value C.sub.m for each rotating speed is larger. If the washings Q
are greatly biased, the moving accumulated value C.sub.m is larger
than the set second thresholds, i.e., a corresponding one of the
upper second threshold and the lower second threshold.
[0174] Returning to FIG. 18, if the newest moving accumulated value
C.sub.m is not less than the set second threshold, the control part
30 determines that the washings Q are biased in the dewatering tank
4 and the moving accumulated value C.sub.m falls in the range of
detection 4-2 ("yes" in step S95).
[0175] When it is determined that the moving accumulated value
C.sub.m falls in the range of detection 4-2 ("yes" in step S95),
the control part 30 acquires the rotating speed L of the motor 6
(step S96) at the judged time point, i.e., the time point when it
is detected in detection 4-2 that the washings Q are biased.
[0176] Next, the control part 30 causes the motor 6 to stably
rotate at the acquired rotating speed L, strictly speaking, a
rotating speed obtained by rounding off the digit in the units
position of the rotating speed L, so that the washings Q are
continuously dewatered (step S79). At this moment, the control part
30 prolongs dewatering time at the rotating speed L so as to obtain
a dewatering effect same as that obtained through the dewatering at
the original target rotating speed of 800 rpm.
[0177] Next, if it is determined in detection 4-2 that the washings
Q are not biased, the control part 30 ends detection 4-2 and causes
the motor 6 to stably rotate at 800 rpm so as to continue to
dewater the washings Q (the above step S78) when the rotating speed
of the motor 6 reaches the target rotating speed ("no" in step
S94).
[0178] In this way, in the third acceleration stage, the biasing of
the washings Q in the dewatering tank 4 is double detected in a
mode adopting information values (such as C.sub.n) and the first
threshold (i.e., detections 1.about.3), and a mode adopting the
duty ratio d.sub.m and the second thresholds (i.e., detection 4),
so that eccentric rotation of the dewatering tank 4 may be reliably
inhibited early.
[0179] The present disclosure is not limited to the embodiments as
described above, but various changes may be made within a scope
recorded in the claims.
[0180] FIG. 19 is a flow chart illustrating a first modification of
the control action of detection 3 in the third acceleration stage.
It shall be noted that, throughout the drawings including FIG. 19,
same reference numerals are used for same steps in other diagrams,
and detailed description with respect to the repeated steps is
omitted. By referring to FIG. 19, like in detection 3, the control
part 30 causes the motor 6 to accelerate to the target rotating
speed of 800 rpm (step S61), and enabled the count value "n" to be
added by 1 (step S63) once the interruption W is inputted ("yes" in
step S62). In the third acceleration stage, the control part 30
starts detection 3 (step S64). Next, after it is determined that
the detection 3 is OK ("yes" in step S65), the control part 30 ends
detection 3 and resets the count value n to zero when the rotating
speed of the motor 6 reaches 800 rpm ("yes" in step S66), so that
the motor 6 stably rotates at 800 rpm, and dewatering continues
(step S67).
[0181] In the first modification, during detection 3, the control
part 30 monitors a maximum G.sub.max of G when the rotating speed
of the motor 6 is 250.about.300 rpm (step S68). With respect to the
maximum G.sub.max, a specified reference value smaller than the
first threshold is set and stored in the memory 32. If the maximum
G.sub.max does not exceed the reference value ("yes" in step S68),
the control part 30 increases all of the second thresholds adopted
in detection 4 (step S69).
[0182] That is, if the maximum G.sub.max in detection 3 is less
than the reference value, the dewatering tank 4 is at least in a
state of being in static balance. If the dewatering tank 4 is in a
state that the balance can be achieved statically or dynamically,
although it is OK in both of detection 3 and detection 4,
longitudinal shaking of the dewatering tank 4 may also be
sensitively detected by the concurrently executed detection 4 even
if detection 3 is OK in a state of dynamic imbalance. Thus, it can
be imagined that, if the C.sub.m in detection 4 is too large, the
NG is caused. As a result, a poor condition of rotation stopping of
the dewatering tank 4 may occur when detection 4 is carried out
although vibrations of the outer tank 3 and the dewatering tank 4
are not large.
[0183] In order to prevent such poor condition, the control part 30
estimates that the vibrations of the outer tank 3 and the
dewatering tank 4 are not large and carries out a control of
widening the second thresholds of detection 4 in step S69 as long
as the maximum G.sub.max in detection 3 is a low value below the
reference value ("yes" in step S68). That is, error detection of
detection 4 adopting the duty ratio d.sub.m is prevented through
detection 3.
[0184] FIG. 20 relates to a second modification of the control
action in detection 3, and is a schematic diagram illustrating the
interior of the dewatering tank 4 in the dewatering operation. For
example, as shown in FIG. 20(a), the washings Q in the dewatering
tank 4 might be arranged in the dewatering tank 4 with a first
washing Q1 and a second washing Q2 being placed at a half of the
dewatering tank 4 relative to the central axis 17. When the
dewatering tank 4 rotates at the high speed of 800 rpm in the
state, the dewatering tank 4 which is perfectly round initially
deforms into an elliptic shape with a long edge formed in an
opposite position direction of the first washing Q1 and the second
washing Q2, as shown in FIG. 20 (b), and may contact with the
circumferential wall 3A of the outer tank 3. In order to prevent
such problem, in the third acceleration stage, control of detection
3 of the second modification shown in FIG. 21 may be
implemented.
[0185] By referring to FIG. 21, the control part 30 causes the
motor 6 to accelerate to the target rotating speed of 800 rpm (step
S61), and enables the count value n to be added by 1 (step S63)
once the interruption W is inputted ("yes" in step S62), as it does
in detection 3. In the third acceleration stage, the control part
30 starts detection 3 (step S64). Next, after it is determined that
detection 3 is OK ("yes" in step S65), the control part 30 ends
detection 3, resets the count value n to zero and causes the motor
6 to steadily rotate at 800 rpm so as to continuously carry out
dewatering (step S67) when the rotating speed of the motor 6
reaches 800 rpm ("yes" in step S66).
[0186] With respect to the maximum G.sub.max in detection 1, a
specified first reference value smaller than the first threshold is
set; with respect to the maximum G.sub.max in detection 2, a
specified second reference value smaller than the first reference
value is set; and with respect to the maximum G.sub.max in
detection 3 when the rotating speed of the motor 6 is 250.about.300
rpm, a specified third reference value smaller than the second
threshold is set. The first reference value.about.the third
reference value are stored in the memory 32.
[0187] As for detection 3 of the second modification, the previous
maximum G.sub.max in detection 1 never exceeds the first reference
value ("yes" in step S101), the previous maximum G.sub.max in
detection 2 never exceeds the second reference value ("yes" in step
S102), and if the maximum G.sub.max in detection 3 when the
rotating speed of the motor 6 is 250.about.300 rpm never exceeds
the third reference value ("yes" in step S103), the control part 30
decreases all the second thresholds in detection 4 (step S104).
[0188] That is, as long as the maximums G.sub.max in respective
detection among detections 1.about.3 are smaller values below the
corresponding reference values ("yes" in steps S101.about.S103),
the washings Q in the dewatering tank 4 may be in a state of being
evenly distributed in the dewatering tank 4 or in a state of being
tidily divided into two parts, as shown in FIG. 20.
[0189] Thus, as long as the maximums G.sub.max in respective
detection among detections 1.about.3 are smaller values below the
corresponding reference values ("yes" in steps S101.about.S103),
the control part 30 decreases the second thresholds (step S104) if
the washings Q in the dewatering tank 4 are assumed to be in a
state of being divided into two parts. Therefore, in detection 4
which is executed in parallel with detection 3, before the
dewatering tank 4 deforms greatly toward the elliptic shape,
detection 4-2 is enabled to be NG in step S95, so as to continue
the dewatering operation at the rotating speed that makes the
dewatering tank 4 not contact with the outer tank 3 in step S79
(referring to FIG. 18).
[0190] As described above, in the modifications 1 and 2, the
control part 30 properly changes the second thresholds according to
the maximum G.sub.max of the accumulated values G in at least one
of the first acceleration stage, the second acceleration stage and
the third acceleration stage. Therefore, by changing the second
thresholds to be suitable for the current situation in the
dewatering tank 4, the biasing of the washings Q may be detected
with high accuracy, so that eccentric rotation of the dewatering
tank 4 is inhibited early. It shall be noted that, controls of the
modification 1 and the modification 2 may also be carried out in
parallel.
[0191] FIG. 22 and FIG. 23 are flow charts illustrating a control
action of a third modification in the dewatering operation. As
described above, the dewatering machine 1 may electrically detect
eccentric rotation of the dewatering tank 4 through detections
1.about.4, and may also mechanically detect eccentric rotation of
the dewatering tank 4 through the safety switch 36. That is, the
biasing of the washings Q may be double detected in an electric
mode and a mechanical mode. The electric mode is a mode of carrying
out detection based on a relationship of information values (i.e.,
the accumulated value G, the moving accumulated value C.sub.m, the
first threshold and the second threshold) related to the rotation
state of the motor 6 at 800 rpm, and the mechanical mode is a mode
of carrying out detection through contact between the safety switch
36 and the outer tank 3. Therefore, either in the case that it is
determined in detections 1.about.4 that the washings Q are biased,
or in the case that the eccentric rotation of the dewatering tank 4
is detected by the safety switch 36, the control part 30 causes the
dewatering tank 4 to stop rotating.
[0192] Both of the mechanical mode and the electric mode are
expected to detect eccentric rotation of the dewatering tank 4 at a
same moment. However, in the dewatering machine 1 in a shipment
stage, due to a difference between relative positions of the
dewatering tank 4 and the safety switch 36 caused by an inclined
error of the dewatering tank 4 among individuals of the dewatering
machine 1, the first thresholds and the second thresholds of some
dewatering machines 1 may not be proper. As a result, there is a
time deviation between the mechanical detection and the electrical
detection. Then, when the dewatering machine 1 is used, the
deviation may be eliminated by correcting the first thresholds and
the second thresholds. Although description is made regarding
correcting the first thresholds in detection 1, the present
disclosure is not limited to only correcting the first thresholds
in detection 1, and the first thresholds in detections 2.about.3
and the second thresholds in detection 4 may also be corrected.
[0193] By referring to FIG. 22, the control part 30 causes the
dewatering tank 4 to rotate and start dewatering as the initial
dewatering operation after shipment starts (step S111). Along with
starting of dewatering, detection 1 is carried out in the first
stage. At this time, when the safety switch 36 is switched to "on"
("yes" in step S112), the control part 30 uses the count value n at
this time as n.sub.x and uses the accumulated value G at this time
as G.sub.x (step S113). The first threshold when the count value n
is n.sub.x is a value acquired by subtracting the first specified
value from n.sub.x in the present embodiment. The first specified
value is a positive value.
[0194] The control part 30 determines whether a value obtained by
subtracting G.sub.x from the previous first threshold is above a
second specified value J (step S114). The second specified value J
is a positive value. In the case that a difference between the
first threshold and the G.sub.x is below the second specified value
J ("no" in step S114), since there substantially does not exist a
time deviation between the moment that the eccentric rotation is
detected by detection 1 and the moment that the eccentric rotation
is detected by the safety switch 36, the first threshold may be
determined as proper, and the control part 30 continuously carries
out operation without changing the first threshold (step S115).
[0195] In the case that the difference between the first threshold
and G.sub.x is above the second specified value J ("yes" in step
S114), it can be determined that there exists a time deviation
between the moment at which the eccentric rotation is detected by
detection 1 and the moment at which the eccentric rotation is
detected by the safety switch 36. Therefore, it can be determined
that the moment at which the eccentric rotation is detected by
detection 1 may be slower than that at which the eccentric rotation
is detected by the safety switch 36. However, since the deviation
may have occurred by accident, the control part 30 enables a
correction alternate value U, the factory default of which is zero,
to be added by 1 temporarily (step S116). If the correction
alternate value U added by 1 is smaller than a specified upper
limit value (which is 3 herein) ("no" in step S117), the control
part 30 does not change the first threshold and enables operation
to continue (step S118).
[0196] On the other hand, if the correction alternate value U added
by 1 reaches the upper limit value ("yes" in step S117), the
current first threshold is not proper because there apparently
exists a time deviation between the moment at which the eccentric
rotation is detected by detection 1 and the moment at which the
eccentric rotation is detected by the safety switch 36. Therefore,
the control part 30 sets a value acquired by subtracting the second
specified value J from the first threshold as a new first
threshold, so as to change and decrease the first threshold (step
S119). Next, the control part 30 resets the correction alternate
value U to zero (step S120) and enables operation to continue (step
S121).
[0197] In this way, if a difference between the accumulated value
G.sub.x and the first threshold when eccentric rotation of the
dewatering tank 4 is detected by the safety switch 36 is above a
specified value ("yes" in step S114), the control part 30 corrects
the first threshold (step S119). Therefore, in detection 1 of
dewatering after the first threshold being corrected, whether the
washings Q are biased may be detected with high accuracy through
the corrected first threshold, so that eccentric rotation of the
dewatering tank 4 is inhibited early.
[0198] By referring to FIG. 23, under a condition that the safety
switch 36 is not started ("no" in step S112), if the accumulated
value G does not exceed the first threshold ("no" in step S113),
the control part 30 does not change the correction alternate value
which is zero initially (step S132) and enables the operation to
continue (step S133).
[0199] On the other hand, under a condition that the safety switch
36 is not started ("no" in step S112), when the accumulated value G
reaches the first threshold and the detect result of detection 1 is
NG ("yes" in step S113), the control part 30 sets the count value n
at this moment to be n.sub.y and set the accumulated value G at
this moment to be G.sub.y. The first threshold when the count value
n is n.sub.y is a value acquired by subtracting the first specified
value from n.sub.y in the present embodiment.
[0200] The control part 30 determines whether G.sub.y is above a
value T obtained by adding the first threshold and a third
specified value together (step S135). The third specified value is
a positive value. Under a condition that G.sub.y is less than T
("no" in step S135), since there substantially exists no time
deviation between the moment at which the eccentric rotation is
detected by detection 1 and the moment at which the eccentric
rotation is detected by the safety switch 36, the first threshold
is determined to be proper. Therefore, the control part 30 does not
change the first threshold and enables the operation to continue
(step S136).
[0201] Under a condition that G.sub.y is above T ("yes" in step
S135), it can be determined that there exists a time deviation
between the moment at which the eccentric rotation is detected by
detection 1 and the moment at which the eccentric rotation is
detected by the safety switch 36, and the moment at which the
eccentric rotation is detected by detection 1 is much earlier than
that at which the eccentric rotation is detected by the safety
switch 36. However, since the deviation might have occurred by
accident, the control part 30 enables a correction alternate value
V to be added by 1 temporarily (step S137). Under a condition that
the correction alternate value V added by 1 is less than a
specified upper limit value (which is 3 herein) ("no" in step
S138), the control part 30 does not change the first threshold and
enables the operation to continue (step S139).
[0202] On the other hand, under a condition that the correction
alternate value V added by 1 reaches the specified upper limit
value ("yes" in step S138), the first threshold is not proper
because there apparently exists a time deviation between the moment
at which the eccentric rotation is detected by detection 1 and the
moment at which the eccentric rotation is detected by the safety
switch 36. Therefore, the control part 30 sets a value obtained by
adding the first threshold and the third specified value together
to be a new first threshold, thereby changing the first threshold
and enabling the first threshold to be widened (step S140). Next,
the control part 30 resets the correction alternate value V to zero
(step S141) and enables the operation to continue (step S142).
[0203] In this way, if the control part 30 determines that the
washings Q are biased before eccentric rotation is detected by the
safety switch 36 ("yes" in step S131), the first threshold is
corrected (step S140). Thus, in detection 1 of dewatering after the
first threshold being corrected, biasing of the washings Q may be
detected with high accuracy through the corrected first threshold,
so that eccentric rotation of the dewatering tank 4 is inhibited
early. It shall be noted that, the modification 3 may also be
combined with modification 1 and modification 2.
[0204] Next, description is made to a fourth modification. With
respect to the safety switch 36, the following conditions may be
imagined: although vibration of the dewatering tank 4 is not so
large, due to a moving mode of the outer tank 3, the safety switch
36 may be started by light contact with the outer tank 3. In order
to prevent the dewatering tank 4 from stopping rotating caused by
error detection of such mechanical mode, a control action of the
fourth modification is carried out in parallel with detection 1. In
the control action of the fourth modification, a threshold,
different from the first threshold, is used (which is set to be a
fourth threshold). The fourth threshold may also be a value same as
the first threshold. However, preferably, the fourth threshold is a
value lower than the first threshold. In the following, description
is made on a premise that the fourth threshold is slightly less
than the first threshold.
[0205] FIG. 24 is a flow chart illustrating a control action of the
fourth modification. By referring to FIG. 24, the control part 30
enables the dewatering tank 4 to rotate and starts dewatering (step
S151) along with starting of the dewatering operation. Along with
dewatering, detection 1 is carried out in the first acceleration
stage. At this time, when the safety switch 36 is switched to "on"
("yes" in step S152), the control part 30 sets the accumulated
value G at this time to be G.sub.z (step S153).
[0206] The control part 30 determines whether G.sub.z is above the
fourth threshold (step S154). If G.sub.z is above the fourth
threshold ("yes" in step S154), a result of starting the safety
switch 36, i.e., detection carried out by the safety switch 36, is
normal since the moment at which eccentric rotation is detected by
detection 1 and the moment at which eccentric rotation is detected
by the safety switch 36 are deemed to be consistent approximately.
Therefore, the control part 30 determines that the washings Q are
biased and causes the dewatering tank 4 to stop rotating (step
S155). It shall be noted that, since detection 1 is executed
simultaneously, the control part 30 may also determine that the
washings Q are biased (step S33 in FIG. 9B) and cause the
dewatering tank 4 to stop rotating (step S41 in FIG. 12) when the
accumulated value G becomes above the first threshold ("yes" in
step S32 in FIG. 9B), even if the safety switch 36 is not started
("no" in step S152).
[0207] On the other hand, under a condition that G.sub.z when the
safety switch 36 is started is less than the fourth threshold ("no"
in step S154), the control part 30 determines that vibration of the
dewatering tank 4 is negligibly small, the safety switch 36 is
considered to be subjected to false starting and the operation is
continued (step S156). Therefore, a success rate of the dewatering
operation may be improved.
[0208] However, when the safety switch 36 is restarted while the
operation is continuing hereafter, and the starting number of the
safety switch 36 reach a specified number (which is 3 herein) from
the beginning of dewatering operation ("yes" in step S157), the
control part 30 determines that the safety switch 36 is started
normally and the washings Q are biased, and causes the dewatering
tank 4 to stop rotating (step S155). In other words, until times of
eccentric rotation detected by the safety switch 36 before it is
determined that the washings Q are biased reach the specified
number ("no" in step S157), the control part 30 suspends rotation
stopping of the dewatering tank 4, and the operation continues.
Therefore, rotation stopping of the dewatering tank 4 caused by
false detection of the mechanical mode of the safety switch 36 may
be prevented, and eccentric rotation of the dewatering tank 4 is
inhibited early. It shall be noted that, the specified number
herein is not limited to 3 and may also be 1. Moreover, preferably,
the control action of the modification 4 is executed in the first
acceleration stage where the rotating speed is low to an extent
that no problem is generated even ignoring starting of the safety
switch 36 in step S156. Certainly, the modification 4 may also be
combined with modification 1, modification 2 and modification
3.
[0209] In addition, a modification 5, as a further modification of
the modification 4, may also carry out the control action shown in
FIG. 25. In modification 5, steps S153 and S154 in modification 4
are omitted. In this case, beginning from dewatering starting (step
S151), even if the safety switch 36 is switched on ("yes" in step
S152), the control part 30 may also determines that the safety
switch 36 is started by mistake and causes the operation to
continue (step S156) if the starting number of the safety switch 36
do not reach the specified number (which is 3 herein) ("no" in step
S157). However, as described above, since detection 1 is executed
simultaneously, the control part 30 may cause the dewatering tank 4
to stop rotating (step S41 in FIG. 12) when the accumulated value G
becomes above the first threshold ("yes" in step S32 in FIG. 9B).
That is, if the accumulated value G is less than the first
threshold, the control part 30 may neglect starting of the safety
switch 36 when the starting number is not greater than 2.
[0210] On the other hand, when the starting number of the safety
switch 36 reach 3 ("yes" in step S157), the control part 30
determines that a result detected by the safety switch 36 is normal
and the washings Q are biased, thereby enabling the dewatering tank
4 to stop rotating (step S155). In other words, even in
modification 5, like modification 4, until times of eccentric
rotation detected by the safety switch 36 before it is determined
that the washings Q are biased reaches the specified number ("no"
in step S157), the control part 30 suspends rotation stopping of
the dewatering tank 4, and the operation continues. Besides
modification 4, modification 5 may also be combined with
modifications 1.about.3. However, in modification 4, since false
starting of the safety switch 36 is determined based on the fourth
threshold less than the first threshold (referring to FIG. 24), the
biasing of the washings Q may be determined earlier compared with
modification 5 so as to cause the dewatering tank 4 to stop
rotating.
[0211] In the above present embodiment, on the premise that the
motor 6 is a variable frequency motor, the motor 6 is controlled
based on the duty ratio. However, under a condition that the motor
6 is a brush motor, the motor 6 is controlled based on the voltage
applied to the motor 6 instead of the duty ratio.
[0212] Moreover, in the above description, although specific
numerical values including 120 rpm, 240 rpm, 800 rpm, etc. are used
as the rotating speed, the specific numerical values are varied
according to the performance of the dewatering machine 1. Moreover,
in the above description, in detections 1.about.3, the accumulated
value G is calculated based on the moving average value C.sub.n.
However, if not influenced by errors, etc, the accumulated value G
may also be calculated based on any information value of other
information values such as A.sub.n and B.sub.n, which may be
reduced as the rotating speed of the motor 6 increases. In
addition, although the accumulated value G is an accumulated value
of the moving average values E.sub.n, the accumulated value G may
also be an accumulated value of difference D.sub.n if influences
including opposite position errors of NS groups do not exist. In
addition, in detection 4, although the duty ratio is acquired to
perform determination, the acquired duty ratio may be original data
of the acquired duty ratios, may also be a correction value
corrected as needed and may also be an index value acquired by
transforming the duty ratio just like the moving accumulated value
C.sub.m.
* * * * *