U.S. patent application number 12/232555 was filed with the patent office on 2009-03-26 for pump.
This patent application is currently assigned to Matsushita Electric Works, Ltd.. Invention is credited to Toshiharu Hashimoto, Masaaki Nishikata, Takafumi Seki, Shinji Suematsu.
Application Number | 20090081059 12/232555 |
Document ID | / |
Family ID | 39864776 |
Filed Date | 2009-03-26 |
United States Patent
Application |
20090081059 |
Kind Code |
A1 |
Seki; Takafumi ; et
al. |
March 26, 2009 |
Pump
Abstract
A pump includes an impeller for sucking and discharging liquid,
a pump case having a suction port and a discharge port through
which the liquid is sucked and discharged, and a partition
cooperating with the pump case to form a pump chamber in which the
impeller is rotatably received. The pump is further includes a
rotor having a magnet for rotatingly driving the impeller and a
stator having claw-shaped magnetic poles for applying a rotational
driving force to the rotor, the rotor and the stator constituting a
claw pole type motor that serves as a driving power source of the
pump. At least the stator is entirely coated with a molded
resin.
Inventors: |
Seki; Takafumi; (Fukuoka,
JP) ; Hashimoto; Toshiharu; (Ibaraki, JP) ;
Nishikata; Masaaki; (Fukuoka, JP) ; Suematsu;
Shinji; (Fukuoka, JP) |
Correspondence
Address: |
BACON & THOMAS, PLLC
625 SLATERS LANE, FOURTH FLOOR
ALEXANDRIA
VA
22314-1176
US
|
Assignee: |
Matsushita Electric Works,
Ltd.
Osaka
JP
|
Family ID: |
39864776 |
Appl. No.: |
12/232555 |
Filed: |
September 19, 2008 |
Current U.S.
Class: |
417/420 ;
417/423.7 |
Current CPC
Class: |
F04D 13/064 20130101;
F04D 13/0673 20130101 |
Class at
Publication: |
417/420 ;
417/423.7 |
International
Class: |
F04D 13/06 20060101
F04D013/06 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 20, 2007 |
JP |
2007-243789 |
Claims
1. A pump comprising: an impeller for sucking and discharging
liquid; a pump case having a suction port and a discharge port
through which the liquid is sucked and discharged; a partition
cooperating with the pump case to form a pump chamber in which the
impeller is rotatably received; a rotor having a magnet for
rotatingly driving the impeller; and a stator having claw-shaped
magnetic poles for applying a rotational driving force to the
rotor, the rotor and the stator constituting a claw pole type motor
that serves as a driving power source of the pump, wherein at least
the stator is entirely coated with a molded resin.
2. A pump comprising: an impeller for drawing and discharging
liquid; a pump case having a suction port and a discharge port
through which the liquid is sucked and discharged; a partition
cooperating with the pump case to form a pump chamber in which the
impeller is rotatably received; a rotor having a magnet for
rotatingly driving the impeller; and a stator having claw-shaped
magnetic poles for applying a rotational driving force to the
rotor, the rotor and the stator constituting a claw pole type motor
that serves as a driving power source of the pump, wherein the
stator is formed of a dust core molded by compressing magnetic
powder.
3. The pump of claim 1, wherein the stator is formed of a dust core
molded by compressing magnetic powder.
4. The pump of claim 1, wherein the claw pole type motor has an
outer rotor structure in which the rotor is arranged outside the
partition and the stator is arranged inside the partition.
5. The pump of claim 2, wherein the claw pole type motor has an
outer rotor structure in which the rotor is arranged outside the
partition and the stator is arranged inside the partition.
6. The pump of claim 3, wherein the claw pole type motor has an
outer rotor structure in which the rotor is arranged outside the
partition and the stator is arranged inside the partition.
7. The pump of claim 1, wherein the claw pole type motor has an
inner rotor structure in which the rotor is arranged inside the
partition and the stator is arranged outside the partition.
8. The pump of claim 2, wherein the claw pole type motor has an
inner rotor structure in which the rotor is arranged inside the
partition and the stator is arranged outside the partition.
9. The pump of claim 3, wherein the claw pole type motor has an
inner rotor structure in which the rotor is arranged inside the
partition and the stator is arranged outside the partition.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a pump incorporating a claw
pole type motor and, more particularly, to a technique of
increasing a pump efficiency and reducing a pump size.
BACKGROUND OF THE INVENTION
[0002] It is known that a pump for sucking and discharging, e.g.,
liquid, employs a claw pole type motor with claw-shaped magnetic
poles as a motor for rotatingly driving an impeller (see, e.g.,
Japanese Patent Laid-open Application No. 2003-505648). The claw
pole type motor is simple in structure and therefore is
advantageous in that it can enjoy enhanced productivity and reduced
production costs.
[0003] Typically, the pump includes an impeller for sucking and
discharging liquid, a pump case with suction and discharge ports, a
partition cooperating with the pump case to form a pump chamber in
which the impeller is rotatably received, a rotor having a magnet
for rotatingly driving the impeller and a stator having claw-shaped
magnetic poles for applying a rotational driving force to the
rotor. The rotor and the stator are liquid-tightly isolated from
each other by means of the partition.
[0004] In this kind of pump, there have existed a demand for
enhancement of a suction and discharge capacity (pump efficiency)
and a demand for reduction in size.
SUMMARY OF THE INVENTION
[0005] In view of the above, the present invention provides a pump
capable of assuring increased efficiency and reduced size.
[0006] In accordance with the present invention, there is provided
a pump including: an impeller for sucking and discharging liquid; a
pump case having a suction port and a discharge port through which
the liquid is sucked and discharged; a partition cooperating with
the pump case to form a pump chamber in which the impeller is
rotatably received; a rotor having a magnet for rotatingly driving
the impeller; and a stator having claw-shaped magnetic poles for
applying a rotational driving force to the rotor, the rotor and the
stator constituting a claw pole type motor that serves as a driving
power source of the pump, wherein at least the stator is entirely
coated with a molded resin.
[0007] In order to enhance pump efficiency and to reduce pump size
in a pump using a claw pole type motor as its driving power source,
a stator is entirely coated with molded resin or is formed of a
dust core.
[0008] In accordance with the pump of the present invention, a
stator is entirely coated with molded resin, whereby the heat of
liquid sucked into a pump case through an suction port and the heat
emitted from a motor (a rotor and a stator) are dissipated through
the molded resin. This makes it possible to enhance pump
efficiency. With the pump of the present invention, the molded
resin acts to dissipate heat. This eliminates the need to
additionally provide a cooling device, which assists in reducing
the size of the pump itself.
[0009] With the pump of the present invention, the stator is formed
of a dust core. This makes it possible to suppress generation of an
eddy current and to reduce the loss of electric current,
consequently increasing pump efficiency. Since the stator is formed
of a dust core in the pump of the present invention, it is possible
to reduce the thickness of the stator itself and, eventually, to
reduce the size of the pump itself.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The object and features of the present invention will become
apparent from the following description of embodiments given in
conjunction with the accompanying drawings, in which:
[0011] FIG. 1 is a perspective view of a pump in accordance with a
first embodiment of the present invention;
[0012] FIG. 2 is a section view taken along line A-A in FIG. 1;
[0013] FIG. 3 is a section view of a pump in accordance with a
second embodiment of the present invention;
[0014] FIG. 4 is a section view of a pump in accordance with a
fourth embodiment of the present invention;
[0015] FIG. 5 is a section view of a conventional pump in which
magnetic poles are detected by a hall sensor; and
[0016] FIG. 6 is a section view of a pump in accordance with a
fifth embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0017] Hereinafter, an exemplary embodiment of the present
invention will be described with reference to FIGS. 1 to 6, which
form a part hereof.
First Embodiment
[0018] FIG. 1 is a perspective view of a pump in accordance with a
first embodiment of the present invention. FIG. 2 is a section view
taken along line A-A in FIG. 1.
[0019] The pump in accordance with the first embodiment includes an
impeller 1 for sucking and discharging liquid, a pump case 4 with a
suction port 2 and a discharge port 3 through which the liquid is
sucked and discharged, a partition 6 cooperating with the pump case
4 to form a pump chamber 5 in which the impeller 1 is rotatably
received, a rotor 8 having a magnet 7 for rotatingly driving the
impeller 1, a stator 10 having claw-shaped magnetic poles 9 for
applying a rotational driving force to the rotor 8 and a control
circuit board 11 for controlling magnetic field generated by the
stator 10. The rotor 8, the stator 10 and the control circuit board
11 constitute a claw pole type motor that serves as a driving power
source of the pump.
[0020] The pump of the first embodiment employs, as its driving
power source, the claw pole type motor having a so-called outer
rotor structure in which the rotor 8 is arranged outside the
partition 6 and the stator 10 is arranged inside the partition
6.
[0021] The pump chamber 5 is formed by coupling the partition 6 for
liquid-tightly isolating the rotor 8 from the stator 10 (for
isolating a pump part from a motor part) to the pump case 4 having
the suction port 2 opened at the center of a ceiling surface and
the discharge port 3 formed in a sidewall. A seal member (not
shown) for water-tightly partitioning the pump part and the motor
part is arranged in the coupling portion of the pump case 4 and the
partition 6.
[0022] The impeller 1 is rotatably supported through a bearing
portion 13 with respect to a fixed shaft 12 provided within the
pump chamber 5. When rotated about the fixed shaft 12, the impeller
1 applies a centrifugal force to the liquid sucked into the pump
chamber 5 through the suction port 2, thereby discharging the
liquid out of the pump through the discharge port 3. The liquid
sucked and discharged by the impeller 1 may be, e.g., hot water
heated to a temperature of about 80.degree. C. A reception plate 45
is arranged above the bearing portion 13.
[0023] The rotor 8 has a cylindrical body integrally formed with
the impeller 1. The magnet 7 forming a magnetic circuit (magnetic
flux) is arranged in the inner wall of the cylindrical body of the
rotor 8. In between the magnet 7 and the partition 6, there is
provided a gap (clearance) enough to keep the magnet 7 and the
partition 6 out of contact during rotation of the rotor 8.
[0024] The stator 10 is arranged inside the cylindrical rotor 8 in
a mutually facing relationship, with the partition 6 interposed
therebetween. The stator 10 includes an iron core having a
plurality of claw-shaped magnetic poles (claw poles) 9, and an
annular coil (winding) 15 arranged in the iron core via an
insulation plate (not shown). The stator 10 and the partition 6 may
make surface-to-surface contact with each other. The stator 10 is
entirely coated with a molded resin 40 composed of, e.g.,
unsaturated polyester.
[0025] With this claw pole type stator 10, the magnetic fields
generated by energizing the annular coil 15 can be transferred from
the claw-shaped magnetic poles 9 to the rotor 8 with increased
efficiency.
[0026] The control circuit board 11 is provided at the rear side of
the stator 10. In response to a signal issuing from a position
detector (not shown), the control circuit board 11 controls the
magnetic fields generated from the annular coil 15. The control
circuit board 11 and the stator 10 are coated with the molded resin
40.
[0027] In the pump configured as above, as the magnetic fields
generated by energization of the annular coil 15 are transferred
from the claw-shaped magnetic poles 9 to the magnet 7, the magnet 7
is attracted and repelled so that the impeller 1 integrally formed
with the rotor 8 can rotate about the fixed shaft 12. Rotation of
the impeller 1 initiates a pumping action whereby liquid is sucked
into the pump chamber 5 through the suction port 2 and pressurized
within the pump chamber 5. The pressurized liquid is pumped
radially circumferentially and discharged out of the pump through
the discharge port 3.
[0028] The stator 10 generates heat as the annular coil 15 is
energized. The liquid sucked and discharged by the impeller 1 is
hot water of about 80.degree. C. as mentioned above. Therefore, the
motor is heated up, which may lead to reduction in the suction and
discharge efficiency (motor efficiency). Since the stator 10 is
entirely coated with the molded resin 40 according to the present
embodiment, it is possible to dissipate the heat of the motor and
the heat of the liquid out of the motor through the molded resin
40. With the pump of the present embodiment, it is therefore
possible to cool the motor without having to use an additional
cooling device, which assists in enhancing the motor efficiency and
reducing the motor size.
[0029] Further, since the stator 10 is entirely coated with the
molded resin 40 according to the present embodiment, it is possible
for the molded resin 40 to protect the stator 10 and increase the
strength thereof.
[0030] In the pump of the present embodiment, the internal pressure
of the pump chamber 5 is increased as the impeller 1 rotates. The
internal pressure acts against the partition 6. In case that the
thickness of the partition 6 is increased to secure a pressure
resistance enough to resist the internal pressure, the motor size
becomes greater. By employing a structure in which the stator 10
makes surface-to-surface contact with the partition 6, it is
possible for the stator 10 to withstand and reduce the pressure
applied to the partition 6. In the pump of the present embodiment,
it is therefore possible to increase the internal hydraulic
pressure of the pump without having to make the partition 6 thick.
Further, since the thickness of the partition 6 can be reduced, it
is possible to reduce the material cost in the pump of the present
embodiment.
Second Embodiment
[0031] In a pump in accordance with a second embodiment of the
present invention, a stator 10' is formed of a dust core. Other
structures of the pump of the second embodiment are the same as
those of the outer rotor type pump described above in connection
with the first embodiment, except that the stator 10' is not coated
with the molded resin 40. Those portions of the second embodiment
different from the first embodiment will now be described, and
redundant description of the same portions will be omitted.
[0032] FIG. 3 is a section view of the pump in accordance with the
second embodiment of the present invention. The pump of the second
embodiment employs the stator 10' formed of a dust core which is
molded by filling magnetic powder in a cavity of a mold and
compressing the same. The dust core is of a structure in which
individual iron particles are coated with inorganic insulating
films and bound together by resin. The dust core has advantages in
that it exhibits a reduced iron loss (eddy current loss) at a high
frequency.
[0033] Since the stator 10' is formed of a dust core in the pump of
the second embodiment set forth above, it is possible to use the
stator 10' in a high frequency band of several hundred kHz in which
a stator heretofore made of an electromagnetic steel plate or a
ferrite plate cannot be used satisfactorily. In addition, the pump
is further reduced in size while exercising the same performance as
is available in the conventional case.
Third Embodiment
[0034] A pump in accordance with a third embodiment of the present
invention is made by the combination of the pumps of the first and
second embodiments. The pump of the third embodiment is the same in
structure as the pump of the first embodiment shown in FIGS. 1 and
2 but is produced by combining the structure (the structure of the
first embodiment) in which the stator 10 is entirely coated with
the molded resin 40 and the structure (the structure of the second
embodiment) in which the stator 10' is formed of a dust core.
[0035] The pump of the third embodiment provides the 1b
advantageous effects of the second embodiment as well as those of
the first embodiment. Therefore, it is possible to increase the
motor efficiency by efficiently dissipating the heat of the motor
and the heat of the liquid. It is also possible to reduce the pump
size, while allowing the pump to be used in a high frequency
band.
[0036] With the pump of the third embodiment, the stator 10' formed
of a dust core is relatively low in strength. However, it is
possible to protect the stator 10' from external forces by coating
the entire stator 10' with the molded resin 40.
Fourth Embodiment
[0037] In a pump in accordance with a fourth embodiment of the
present invention, not only the entire stator 10 but also the
partition 6 is coated with the molded resin 40. Other structures of
the pump of the fourth embodiment are the same as those of the
outer rotor type pump described above in connection with the first
embodiment. Those portions of the fourth embodiment different from
the first embodiment will now be described, and redundant
description of the same portions will be omitted.
[0038] FIG. 4 is a section view of the pump in accordance with the
fourth embodiment of the present invention. In the pump of the
fourth embodiment, the partition 6 is entirely coated with the
molded resin 40, in addition to the structure (the structure of the
first embodiment) in which the stator 10 is entirely coated with
the molded resin 40.
[0039] Since the partition 6 is entirely coated with the molded
resin 40, the contact surface between the partition 6 and the
molded resin 40 is increased in the pump of the fourth embodiment.
Therefore, the pump of the fourth embodiment provides not only the
advantageous effects available in the first embodiment but also the
advantageous effects that it is possible to more effectively
dissipate the heat of the motor and the heat of the liquid
transferred through the partition 6. Accordingly, the motor
efficiency can be further increased with the pump of the fourth
embodiment.
[0040] In this kind of pump, it is typical to employ a motor
driving method as shown in FIG. 5, in which the magnet 7 is used as
a rotor and the timing of supplying an electric current is
controlled by detecting the magnetic poles with a hall sensor 41.
However, in case of using the hall sensor 41 as in this example,
the pump itself is increased in size. For preventing the pump from
being increased in size, the magnetic poles of the magnet 7 may be
detected from the waveforms of an electric current, thereby
eliminating the need to use the hall sensor 41. Detection of the
magnetic poles of the magnet 7 from the waveforms of an electric
current is applicable to the pumps of the first to third
embodiments as well as the pump of the fourth embodiment. This
eliminates the need to install the hall sensor 41 near the rotor 8.
Therefore, it becomes possible to reduce the size of the pump
itself.
Fifth Embodiment
[0041] A pump in accordance with a fifth embodiment of the present
invention employs as its driving power source a claw pole type
motor with an inner rotor structure in which a rotor is arranged
inside a partition and a stator is arranged outside the partition.
FIG. 6 is a section view of the pump in accordance with the fifth
embodiment.
[0042] The pump of the fifth embodiment includes an impeller 21 for
sucking and discharging liquid, a pump case 24 with a suction port
22 and a discharge port 23 through which the liquid is sucked and
discharged, a partition 26 cooperating with the pump case 24 to
form a pump chamber 25 in which the impeller 1 is rotatably
received, a rotor 28 having a magnet 27 for rotatingly driving the
impeller 21, a stator 30 having claw-shaped magnetic poles (not
shown) for applying a rotational driving force to the rotor 28 and
a control circuit board 31 for controlling magnetic field generated
by the stator 30. The rotor 28, the stator 30 and the control
circuit board 31 constitute a claw pole type motor that serves as a
driving power source of the pump.
[0043] The pump of the fifth embodiment employs, as its driving
power source, the claw pole type motor having a so-called inner
rotor structure in which the rotor 28 is arranged inside the
partition 26 and the stator 30 is arranged outside the partition
26.
[0044] The pump chamber 25 is formed by coupling the partition 26
for liquid-tightly isolating the rotor 28 from the stator 30 (for
isolating a pump part from a motor part) to the pump case 24 having
the suction port 22 opened at the center of a ceiling surface and
the discharge port 23 formed in a sidewall. A seal member 29 for
liquid-tightly partitioning the pump part and the motor part is
arranged in the coupling portion of the pump case 24 and the
partition 26.
[0045] The rotor 28 has a cylindrical body integrally formed with
the impeller 21. The magnet 27 forming a magnetic circuit (magnetic
flux) is arranged in the outer wall of the cylindrical body of the
rotor 28. The rotor 28 is rotatably supported through a bearing
portion 35 about a fixed shaft 34 whose opposite ends are
respectively fitted into a shaft supporting portion 32 of the pump
case 24 and a shaft supporting portion 33 of the partition 26. The
fixed shaft 34 is held against rotation by means of anti-rotation
plates 36 and 37 attached to the opposite end portions thereof. In
between the magnet 27 and the partition 26, there is provided a gap
(clearance) enough to keep the magnet 27 and the partition 26 out
of contact during rotation of the rotor 28.
[0046] The impeller 21 integrally formed with the rotor 28 rotates
about the fixed shaft 34 and applies a centrifugal force to the
liquid sucked into the pump chamber 25 through the suction port 22,
thereby discharging the liquid out of the pump through the
discharge port 23.
[0047] The stator 30 is arranged outside the rotor 28 in a mutually
facing relationship, with the partition 26 interposed therebetween.
The stator 10 includes an iron core having a plurality of
claw-shaped magnetic poles (claw poles), and an annular coil 38
arranged in the iron core via an insulation plate (not shown). The
stator 30 and the partition 26 may make surface-to-surface contact
with each other. With this claw pole type stator 30, the magnetic
fields generated by energizing the annular coil 38 can be
transferred from the claw-shaped magnetic poles to the rotor 28
with increased efficiency.
[0048] The control circuit board 31 is provided at the rear side of
the partition 26. In response to a signal issuing from a position
detector 39 as a position detecting sensor, the control circuit
board 31 controls the magnetic fields generated from the annular
coil 38. The stator 30, the control circuit board 31 and the
partition 26 are coated in their entirety with a molded resin 40
composed of, e.g., unsaturated polyester.
[0049] In the pump configured as above, as the magnetic fields
generated by energization of the annular coil 38 are transferred
from the claw-shaped magnetic poles to the magnet 27, the magnet 27
is attracted and repelled so that the impeller 21 integrally formed
with the rotor 28 can rotate about the fixed shaft 34. Rotation of
the impeller 21 initiates a pumping action whereby liquid is sucked
into the pump chamber 25 through the suction port 22 and
pressurized within the pump chamber 25. The pressurized liquid is
pumped radially circumferentially and discharged out of the pump
through the discharge port 23.
[0050] Since the claw pole type motor having the inner rotor
structure is entirely coated with the molded resin 40 in the fifth
embodiment, it is possible to dissipate the heat of the motor and
the heat of the liquid out of the motor through the molded resin
40. It is also possible to cool the motor without having to use an
additional cooling device, which assists in enhancing the motor
efficiency and reducing the motor size.
[0051] Further, since the pump is entirely coated with the molded
resin 40 except for the pump case 24 in the present embodiment, it
is possible for the molded resin 40 to protect the entire motor
part including the control circuit board 31 and to increase the
strength thereof.
[0052] In the pump of the fifth embodiment, the internal pressure
of the pump chamber 25 is increased as the impeller 21 rotates. The
internal pressure acts against the partition 26. By employing a
structure in which the stator 30 makes surface-to-surface contact
with the partition 26, it is possible for the stator 30 to
withstand and reduce the pressure applied to the partition 26. In
the pump of the present embodiment, it is therefore possible to
increase the internal hydraulic pressure of the pump without having
to make the partition 26 thick. Further, since the thickness of the
partition 26 can be thin, it is possible to reduce the material
cost in the pump of the present embodiment.
[0053] In the pump of the fifth embodiment, the stator 30 may be
formed of a dust core as in the second embodiment. Furthermore, the
pump of the fifth embodiment may be of a structure in which the
stator 30 is formed of a dust core without coating the same with
the molded resin 40.
[0054] While the invention has been shown and described with
respect to the embodiments, it will be understood by those skilled
in the art that various changes and modifications may be made
without departing from the scope of the invention as defined in the
following claims.
* * * * *