U.S. patent application number 16/098070 was filed with the patent office on 2019-12-05 for centrifugal pump.
The applicant listed for this patent is SHINANO KENSHI KABUSHIKI KAISHA. Invention is credited to Yoshitaka MATSUI.
Application Number | 20190368495 16/098070 |
Document ID | / |
Family ID | 63254329 |
Filed Date | 2019-12-05 |
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United States Patent
Application |
20190368495 |
Kind Code |
A1 |
MATSUI; Yoshitaka |
December 5, 2019 |
CENTRIFUGAL PUMP
Abstract
A centrifugal pump is provided which is capable of achieving
thinning thereof with use of a radial gap-type motor, is smaller in
the flow path loss from a suction flow path to a discharge flow
path, and is capable of efficiently dissipating heat generated by a
coil without inclusion of an extra cooling structure. A rotor (13)
and a pump body (2) are arranged in a concentric manner around a
rotor shaft (7), and a suction side scroll flow path (14) and a
discharge side scroll flow path (15) formed in the pump body (2)
communicate with each other via central flow paths (10b), (10a)
formed in the pump body (2) and an impeller (9).
Inventors: |
MATSUI; Yoshitaka; (Nagano,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SHINANO KENSHI KABUSHIKI KAISHA |
Nagano |
|
JP |
|
|
Family ID: |
63254329 |
Appl. No.: |
16/098070 |
Filed: |
December 14, 2017 |
PCT Filed: |
December 14, 2017 |
PCT NO: |
PCT/JP2017/044883 |
371 Date: |
October 31, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04D 29/44 20130101;
F04D 29/4293 20130101; F04D 29/445 20130101; F04D 29/28 20130101;
F04D 13/0646 20130101; F04D 29/4273 20130101; F04D 13/0666
20130101; H02K 7/14 20130101; H02K 9/19 20130101 |
International
Class: |
F04D 13/06 20060101
F04D013/06; F04D 29/42 20060101 F04D029/42; F04D 29/28 20060101
F04D029/28; F04D 29/44 20060101 F04D029/44 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 22, 2017 |
JP |
2017-030913 |
Claims
1. A centrifugal pump that causes a radial gap-type electric motor
to rotationally drive an impeller to suction a fluid from an outer
circumference side of a pump body into a pump chamber and discharge
the fluid from the pump chamber via the outer circumference side of
the pump body, the centrifugal pump comprising: a base portion; a
rotor shaft having at least one end prevented from dropping off and
supported by the base portion in a standing manner; the impeller
rotatably attached to the rotor shaft; a rotor including a rotor
magnet mounted to the impeller in a concentric fashion; and the
pump body in which a suction side scroll flow path that suctions
the fluid from an outer circumference side of the impeller toward a
radially central portion thereof, a discharge side scroll flow path
that discharges the fluid from the radially central portion of the
impeller toward the outer circumference side thereof, and a stator
including a stator core having stator pole teeth formed and placed
to face radially the rotor magnet are integrally mounted, wherein
the rotor and the pump body are placed in a concentric fashion
around the rotor shaft, and the suction side scroll flow path and
the discharge side scroll flow path formed in the pump body
communicate with each other via central flow paths formed in the
pump body and the impeller.
2. The centrifugal pump according to claim 1, wherein the suction
side scroll flow path includes a suction hole provided on an outer
circumference surface of the pump body and a suction side scroll
groove partitioned in such a manner that the fluid entering from
the suction hole is guided toward a suction side central hole while
revolving in a circumferential direction and formed in such a
manner that a groove depth thereof becomes shallower as the groove
depth goes from the suction hole toward the suction side central
hole.
3. The centrifugal pump according to claim 2, wherein the suction
side scroll flow path is formed between the suction side scroll
groove formed on one end portion in an axial direction of the pump
body and a base portion superposed on the one end portion in the
axial direction.
4. The centrifugal pump according to claim 1, wherein the discharge
side scroll flow path includes a discharge side central hole formed
in such a way as to communicate with the suction side central hole
via the central flow paths and a discharge side scroll groove
partitioned in such a manner that the fluid is guided from the
discharge side central hole to a discharge hole provided on an
outer circumference surface of the pump body while revolving and
formed in such a manner that a groove depth thereof becomes deeper
as the groove depth goes from the discharge side central hole
toward the discharge hole.
5. The centrifugal pump according to claim 4, wherein the discharge
side scroll flow path is formed between the discharge side scroll
groove formed on the other end portion in the axial direction of
the pump body and a base portion superposed on the other end
portion in the axial direction.
6. The centrifugal pump according to claim 1, wherein, on end
surfaces in the axial direction of the pump body, a shallow groove
and a deep groove are placed while being combined such that groove
bottom portions thereof are close to each other in such a manner
that a flow velocity of the fluid becomes uniform in the suction
side scroll flow path and the discharge side scroll flow path.
7. The centrifugal pump according to claim 1, wherein the impeller
includes an annular portion, to which the rotor is mounted, and a
blade portion, which is mounted to the rotor shaft, the annular
portion and the blade portion being molded integrally with each
other.
Description
TECHNICAL FIELD
[0001] The present invention relates to a centrifugal pump which
circulates, for example, a cooling fluid.
BACKGROUND ART
[0002] Conventional electronic apparatuses such as notebook
personal computers are provided with high-heat-generating
electronic components, such as an LED, a CPU, and an MPU, and a
centrifugal pump is used for fluid circulation to cool a control
circuit equipped with these components.
[0003] Moreover, to promote miniaturization and thinning of an
electronic apparatus, it is also necessary to achieve thinning of a
centrifugal pump. For that purpose, a centrifugal pump in which a
suction side flow path for fluid, through which a fluid is usually
suctioned from the center in the axial direction of an impeller, is
pressurized while being scrolled, and is then discharged from the
circumferential direction thereof, is formed to be bent by
90.degree. in such a way as to be parallel to a discharge side flow
path has been proposed (see PTL 1).
[0004] Moreover, since a suction flow path is formed in a casing,
the thickness of the casing becomes thick, and, therefore, a
centrifugal pump in which an axial gap-type motor is employed
instead of a radial gap-type motor as a motor which rotationally
drives an impeller has also been proposed (see PTL 2).
CITATION LIST
Patent Literature
[0005] PTL 1: JP-A-2001-132699
[0006] PTL 2: JP-A-2009-8055
SUMMARY OF INVENTION
Technical Problem
[0007] While thinning can be achieved in a centrifugal pump in
which the above-mentioned axial gap-type motor is employed, the
suction side flow path forms flow paths orthogonal inside a base,
is not seen uniform in the flow path cross-sectional area, and has
a configuration with a high degree of flow path loss. In
particular, since a back yoke equipped with a coil configuring the
axial gap-type motor is formed by being molded inside the base, the
thickness of the base is apt to become thick, so that the suction
side flow path cross-sectional area formed in the base cannot be
secured wide.
[0008] Moreover, since the suction side flow path flows into a pump
chamber side through the inside of a hollow fixed shaft of the
impeller, it is necessary to form the suction side flow path across
the back yoke in the radial direction. Accordingly, since it is
necessary to equip the back yoke with an intermittent portion, a
coli cannot be located in such a portion, so that the flux content
decreases, the effective magnetic flux acting on a rotor also
decreases, and the motor characteristic is also apt to
deteriorate.
[0009] Furthermore, since the suction side flow path is formed
while avoiding the coil, the heat generated by the coil cannot be
efficiently dissipated. If a cooling structure is additionally
provided, thinning cannot be achieved and manufacturing costs also
increase.
SOLUTION TO PROBLEM
[0010] In response to the above issue, it is an object of the
present invention to provide a centrifugal pump which is capable of
achieving thinning thereof with use of a radial gap-type motor, is
smaller in the flow path loss from a suction flow path to a
discharge flow path, and is capable of efficiently dissipating heat
generated by a coil without inclusion of an extra cooling
structure.
[0011] In order to attain the above-mentioned object, the present
invention has the following configuration.
[0012] A centrifugal pump that causes a radial gap-type electric
motor to rotationally drive an impeller to suction a fluid from an
outer circumference side of a pump body into a pump chamber and
discharge the fluid from the pump chamber via the outer
circumference side of the pump body, the centrifugal pump including
a base portion, a rotor shaft having at least one end prevented
from dropping off and supported by the base portion in a standing
manner, the impeller rotatably attached to the rotor shaft, a rotor
including a rotor magnet mounted to the impeller in a concentric
fashion, and the pump body in which a suction side scroll flow path
that suctions the fluid from an outer circumference side of the
impeller toward a radially central portion thereof, a discharge
side scroll flow path that discharges the fluid from the radially
central portion of the impeller toward the outer circumference side
thereof, and a stator including a stator core having stator pole
teeth formed and placed to face radially the rotor magnet are
integrally mounted, wherein the rotor and the pump body are placed
in a concentric fashion around the rotor shaft, and the suction
side scroll flow path and the discharge side scroll flow path
formed in the pump body communicate with each other via central
flow paths formed in the pump body and the impeller.
[0013] According to the above-mentioned configuration of the
centrifugal pump, since the suction side scroll flow path and the
discharge side scroll flow path formed in the pump body communicate
with each other via the central flow paths formed in the pump body
and the impeller, thinning can be achieved even when a radial
gap-type motor is used. Moreover, since a flow path loss leading
from the suction side scroll flow path to the discharge side scroll
flow path is small and the fluid passes in such a manner that these
surround both end surface sides in the axial direction of the
stator core, the heat generated by the coil can be efficiently
dissipated.
[0014] It is desirable that the suction side scroll flow path
include a suction hole provided on an outer circumference surface
of the pump body and a suction side scroll groove partitioned in
such a manner that the fluid entering from the suction hole is
guided toward a suction side central hole while revolving in a
circumferential direction and formed in such a manner that a groove
depth thereof becomes shallower as the groove depth goes from the
suction hole toward the suction side central hole.
[0015] With this, since the fluid suctioned from the suction hole
into the pump body is guided toward the suction side central hole
while revolving along the suction side scroll groove and the groove
depth becomes gradually shallower as the groove depth goes toward
the suction side central hole, the fluid is guided to the impeller
side in the axial direction via the central flow path. At this
time, the height of the pump chamber is unnecessary, and no loss
occurs in the flow path even if thinning is achieved.
[0016] It is desirable that the suction side scroll flow path be
formed between the suction side scroll groove formed on one end
surface in the axial direction of the pump body and another base
portion superposed on the one end surface in the axial
direction.
[0017] With this, the height in the axial direction of the pump
body can be restricted, thinning can be promoted, and assembling
can be performed by superposing the pump body on the base portion,
so that good assembly productivity can also be obtained.
[0018] It is desirable that the discharge side scroll flow path
include a discharge side central hole formed in such a way as to
communicate with the suction side central hole via the central flow
paths and a discharge side scroll groove partitioned in such a
manner that the fluid is guided from the discharge side central
hole to a discharge hole provided on an outer circumference surface
of the pump body while revolving and formed in such a manner that a
groove depth thereof becomes deeper as the groove depth goes from
the discharge side central hole toward the discharge hole.
[0019] With this, the fluid suctioned from the central flow path to
the discharge side central hole is pressurized by rotation of the
impeller, is guided along the discharge side scroll groove, in
which the groove depth thereof becomes gradually deeper as the
groove depth goes from the discharge side central hole toward the
discharge hole, and is then discharged from a discharge port. At
this time, the height of the pump chamber is unnecessary, and no
loss occurs in the flow path even if thinning is achieved.
[0020] It is desirable that the discharge side scroll flow path be
formed between the discharge side scroll groove formed on the other
end surface in the axial direction of the pump body and one base
portion superposed on the other end surface in the axial
direction.
[0021] With this, the height in the axial direction of the pump
body can be restricted, thinning can be promoted, and assembling
can be performed by superposing the pump body on the base portion,
so that good assembly productivity can also be obtained.
[0022] It is desirable that, on end surfaces in the axial direction
of the pump body, a shallow groove and a deep groove be placed
while being combined such that groove bottom portions thereof are
close to each other in such a manner that a flow velocity of the
fluid becomes uniform in the suction side scroll flow path and the
discharge side scroll flow path.
[0023] With this, since a shallow groove and a deep groove are
placed while being combined such that groove bottom portions
thereof are close to each other in such a manner that the flow
velocity of the fluid becomes uniform in the suction side scroll
groove and the discharge side scroll groove formed while being
radially partitioned in the pump chamber, the volume of the pump
chamber can be prevented from increasing in the axial direction,
thinning can be promoted, and the flow path loss leading from a
suction port to a discharge port can be reduced as much as
possible, so that the pump performance can be maintained.
[0024] The impeller can include an annular portion, to which the
rotor is mounted, and a blade portion, which is mounted to the
rotor shaft, the annular portion and the blade portion being molded
integrally with each other.
[0025] With this, the rotor and the impeller can be concurrently
mounted to the rotor shaft, and the location in the axial direction
can be made compact.
Advantageous Effects of Invention
[0026] A centrifugal pump which is capable of achieving thinning
thereof with use of a radial gap-type motor, is smaller in the flow
path loss from a suction flow path to a discharge flow path, and is
capable of efficiently dissipating heat generated by a coil without
inclusion of an extra cooling structure can be provided.
BRIEF DESCRIPTION OF DRAWINGS
[0027] FIG. 1 is a perspective view of a centrifugal pump.
[0028] FIG. 2 is a sectional view in the direction of arrow X-X in
FIG. 1.
[0029] FIGS. 3A and 3B are a top half view obtained by seeing
through a base portion and a sectional view in the direction of
arrow Y-Y in FIG. 1.
[0030] FIGS. 4A and 4B are a suction side perspective view and a
discharge side perspective view of a pump body.
DESCRIPTION OF EMBODIMENTS
[0031] Hereinafter, an embodiment of a centrifugal pump according
to the present invention will be described with reference to the
accompanying drawings illustrated in FIG. 1 to FIGS. 4A and 4B. In
the present embodiment, a centrifugal pump which rotationally
drives an impeller using an inner rotor-type motor of the radial
gap type is described as an example. A DC brushless motor is used
as the inner rotor-type motor.
[0032] In FIG. 1, a centrifugal pump 1 causes a radial gap-type
electric motor to rotationally drive an impeller 9 to suction a
fluid from a suction port 3 formed on an outer circumference of a
pump body 2 and discharge the fluid from a discharge port 4 formed
on the outer circumference of the pump body 2.
[0033] A pair of plate-like base portions 5a, 5b is superposed on
the pump body 2, which is molded with resin, in such a way as to
sandwich both end surfaces thereof, and fixing bolts 6 are
screw-fitted into outer periphery portions of the base portions 5a,
5b, which face each other via the pump body 2, so that the base
portions 5a, 5b and the pump body 2 are integrally mounted.
[0034] Next, a structure of the centrifugal pump 1 is described in
detail with reference to FIG. 2.
[0035] One end of a rotor shaft 7 is supported and fixed in a
standing manner at the base portion 5a, which is one of the pair of
base portions 5a, 5b. The impeller 9 is integrally mounted to the
rotor shaft 7 via a sliding bearing 8. The impeller 9 is prevented
from dropping off by a C-type retaining ring 7a via a thrust
receiver 7b at the other end of the rotor shaft 7, thus being
mounted integrally with the rotor shaft 7.
[0036] In FIGS. 2 and 3B, a rotor 13 is integrally mounted to the
impeller 9. The impeller 9 includes an annular portion 9a, which
forms a central flow path 10a, and a blade portion 9b, which
conveys the fluid from the central portion toward the outer
circumference side, the annular portion 9a and the blade portion 9b
being molded integrally with each other. An annular back yoke 11 is
integrally mounted to the outer circumference surface of the
annular portion 9a and a rotor magnet 12 is integrally mounted to
the outer circumference side thereof via, for example, adhesion or
insert molding. With this, the rotor 13 and the impeller 9 can be
concurrently mounted to the rotor shaft 7 in a concentric fashion,
and the location in the axial direction can be made compact. The
rotor magnet 12 can be a magnet previously molded in an annular
shape or a magnet divided into a plurality of segments. Moreover, a
stepped portion 9c is formed at a suction side opening portion of
the annular portion 9a. Furthermore, in a case where the impeller 9
and the rotor 13 are molded integrally with each other, for
example, in view of durability or the like, it is desirable that
those be integrally molded with, for example, polyphenylene sulfide
(PPS).
[0037] Moreover, a central flow path 10a (a hollow hole) is formed
along the axial direction around a connection portion of the
impeller 9 with the rotor shaft 7. This central flow path 10a is
formed in such a way as to communicate with a central flow path 10b
formed in the pump body 2, as described below. More specifically, a
suction side scroll flow path 14, which is used to suction the
fluid from the outer circumference side of the impeller 9 toward
the radially central portion thereof, and a discharge side scroll
flow path 15, which is used to discharge the fluid from the central
portion of the impeller 9 toward the outer circumference side
thereof, are arranged to communicate with each other via the
central flow paths 10a, 10b.
[0038] Next, a structure of the pump body 2 is described.
[0039] In FIG. 2, the suction side scroll flow path 14, which is
used to suction the fluid from the outer circumference side of the
impeller 9 toward the central portion of a pump chamber 16 in the
radial direction, is formed at one end portion 2a in the axial
direction of the pump body 2. Specifically, the suction side scroll
flow path 14 is formed between a suction side scroll groove
(recessed portion) 14a, which is formed at the one end portion 2a
in the axial direction of the pump body 2, and the base portion 5b,
which is mounted to be superposed on the end surface in the axial
direction in such a way as to cover the suction side scroll groove
14a. Moreover, the one end portion 2a in the axial direction
extends to the radially inner side in such a way as to cover the
annular portion 9a of the impeller 9, and a lip portion 2c (a
return structure), which is formed in an L-shaped manner from that
end portion, is formed. The lip portion 2c is located in such a way
as to mesh with the stepped portion 9c of the annular portion 9a.
The inner circumference surface of the lip portion 2c forms the
central flow path 10b, which communicates with the central flow
path 10a. With this, the fluid can be prevented from flowing back
from a gap between the impeller 9 and the pump body 2 toward the
central flow path 10a.
[0040] Moreover, in FIG. 2, the discharge side scroll flow path 15,
which is used to discharge the fluid from the central portion of
the impeller 9 toward the outer circumference side thereof in the
radial direction, is formed at the other end portion 2b in the
axial direction of the pump body 2. Specifically, the discharge
side scroll flow path 15 is formed between a discharge side scroll
groove (recessed portion) 15a, which is formed at the other end
portion 2b in the axial direction of the pump body 2, and the base
portion 5a. The pump chamber 16, which is provided in the pump body
2, is formed by causing the suction side scroll flow path 14 and
the discharge side scroll flow path 15 to communicate with each
other via the central flow paths 10a, 10b. Furthermore, the suction
side scroll flow path 14 and the discharge side scroll flow path 15
do not necessarily need to be formed between the end portion in the
axial direction of the pump body 2 and the base portion, and,
instead of the base portion, another member can be employed.
[0041] Moreover, as illustrated in FIG. 3A, a stator 17 is mounted
to the pump body 2. The stator 17 includes a stator core 17c in
which stator pole teeth 17b are radially provided in a protruding
manner from a core back portion 17a formed in an annular manner
toward the radially inner side. A coil 17d is wound around each
stator pole tooth 17b.
[0042] As illustrated in FIGS. 3A and 3B, the pump body 2 is
mounted to the base portions 5a, 5b in such a manner that the
stator pole teeth 17b face the rotor magnet 12 in the radial
direction, so that the suction side scroll flow path 14 and the
discharge side scroll flow path 15 communicate with each other via
the central flow paths 10b, 10a formed in the impeller 9.
[0043] According to the above-described configuration of the
centrifugal pump 1, since the suction side scroll flow path 14,
which is used to suction the fluid from the outer circumference
side of the impeller 9 (annular portion 9a) toward the radially
central portion thereof, and the discharge side scroll flow path
15, which is used to discharge the fluid from the central portion
of the impeller 9 (blade portion 9b) toward the outer circumference
side thereof, communicate with each other via the central flow
paths 10b, 10a formed in the pump body 2 and the impeller 9,
thinning can be achieved even if a radial gap-type motor is used.
Moreover, since the flow path loss leading from the suction side
scroll flow path 14 to the discharge side scroll flow path 15 is
small and the fluid passes in such a manner that these surround
both end surface sides in the axial direction of the stator core
17c, the heat generated by the coil 17d can be efficiently
dissipated.
[0044] Next, an internal configuration of the pump body 2 is
described with reference to FIGS. 4A and 4B.
[0045] FIG. 4A is a perspective view illustrating the one end
portion 2a in the axial direction of the pump body 2, in which the
suction side scroll flow path 14 is formed. The fluid, which has
entered from a suction hole 14b provided on the outer circumference
surface of the pump body 2, is guided toward a suction side central
hole 14c while revolving in the circumferential direction. A
suction side scroll groove 14a is partitioned by a partition wall
14d, and is formed in a revolving shape in such a manner that the
groove depth thereof becomes gradually shallower as the groove
depth goes from the suction hole 14b toward the suction side
central hole 14c (the lip portion 2c: see FIG. 3B).
[0046] With this, the fluid, which has been suctioned into the pump
chamber 16 via the suction hole 14b, is guided toward the suction
side central hole 14c while revolving along the suction side scroll
groove 14a. At this time, since the groove depth becomes gradually
shallower as the groove depth goes toward the suction side central
hole 14c, the fluid is guided through the central flow path 10b to
the central flow path 10a on the side of the impeller 9 in the
axial direction. While the fluid moves in a revolving manner in the
pump body 2, the height of the pump chamber 16 is unnecessary, so
that no loss occurs in the flow path even if thinning is
achieved.
[0047] FIG. 4B is a perspective view illustrating the other end
portion 2b in the axial direction of the pump body 2, in which the
discharge side scroll flow path 15 is formed. The fluid, which has
entered from a discharge side central hole 15b through the central
flow path 10a, is guided to a discharge hole 15c provided on the
outer circumference surface of the pump body 2 while revolving in
the circumferential direction along the blade portion 9b of the
impeller 9. The discharge side scroll groove 15a is partitioned by
a partition wall 15d, and is formed in a revolving shape in such a
manner that the groove depth thereof becomes gradually deeper as
the groove depth goes from the discharge side central hole 15b
toward the discharge hole 15c.
[0048] With this, the fluid, which has flowed from the central flow
path 10a into the discharge side central hole 15b, is pressurized
by rotation of the impeller 9 (the blade portion 9b) and is guided
toward the outer circumference surface of the pump body 2. More
specifically, the pressurized fluid is conveyed while revolving
along the discharge side scroll groove 15a, the groove depth of
which becomes gradually deeper as the groove depth goes from the
discharge side central hole 15b toward the discharge hole 15c, and
is then discharged from the discharge port 4. At this time, while
the fluid moves in a revolving manner in the pump body 2, the
height of the pump chamber 16 is unnecessary, so that no loss
occurs in the flow path even if thinning is achieved.
[0049] It is desirable that, on the end surface in the axial
direction of the pump body 2, the suction side scroll groove 14a
and the discharge side scroll groove 15a be formed in such a way as
to be symmetric with respect to a point in such a manner that the
flow velocity of the fluid flowing in these grooves becomes
uniform. Specifically, as illustrated in FIGS. 2 and 3B, the
suction side scroll groove 14a and the discharge side scroll groove
15a are formed in such a manner that a shallow groove and a deep
groove are combined such that the groove bottom portions thereof
are close to each other on the end surfaces in the axial direction
of the pump body 2.
[0050] In this way, since the shallow groove and the deep groove
are formed in combination on the end surfaces in the axial
direction of the pump body 2 in such a manner that the flow
velocity of the fluid flowing in the suction side scroll groove 14a
and the discharge side scroll groove 15a, which are formed by
partitioning in the radial direction in the pump chamber 16,
becomes uniform, there is no increase in the volume of the pump
chamber 16 in the axial direction, thinning can be promoted, and
the flow path loss leading from the suction port 3 to the discharge
port 4 can reduced as much as possible, so that the pump
performance can be maintained.
[0051] In FIG. 1, it is desirable that annular seal members 18, 19
(for example, O rings) be provided between the pump body 2 and a
pair of base portions 5a, 5b, which are superposed on the pump body
2. With this, the sealing performance for fluid of the suction side
scroll flow path 14 and the discharge side scroll flow path 15 can
be enhanced.
[0052] Here, an example of a fluid conveying operation of the
centrifugal pump 1 is described.
[0053] In FIG. 2, when the electric motor is activated, the
impeller 9, which is integrally mounted to the rotor shaft 7, is
rotationally driven.
[0054] With this, the fluid is suctioned from the suction port 3
through the suction side scroll flow path 14, and the fluid
suctioned from the suction hole 14b into the pump chamber 16 is
guided to the suction side scroll groove 14a and is then conveyed
toward the suction side central hole 14c while revolving (see FIG.
4A).
[0055] Then, the fluid is conveyed from the suction side central
hole 14c to the discharge side central hole 15b through the central
flow paths 10a, 10b (see FIG. 3B). The fluid, which has flowed from
the central flow path 10a into the discharge side central hole 15b,
is guided toward the outer circumference surface of the pump body 2
while revolving along the discharge side scroll groove 15a by
rotation of the impeller 9, is pressurized toward the discharge
hole 15c from the discharge side central hole 15b through the
discharge side scroll flow path 15, and is then discharged from the
discharge port 4 (see FIG. 4B).
[0056] As described above, the centrifugal pump 1, in which
thinning is achieved with use of a radial gap-type electric motor,
the flow path loss leading from the suction side scroll flow path
14 to the discharge side scroll flow path 15 is small, and the heat
generated by the coil 17d can be efficiently dissipated without
inclusion of an extra cooling structure, can be provided.
[0057] In the above-described embodiment, the impeller 9, which is
mounted in a concentric manner around the rotor shaft 7, includes
the annular portion 9a and the blade portion 9b integrally molded
with resin, but can be configured with separate components.
[0058] Moreover, while the rotor shaft 8 is fixed and the rotor 13
and the impeller 9 are configured to be rotated, the rotor 13 and
the impeller 9 can be configured to be rotated integrally with the
rotor shaft 7.
* * * * *