U.S. patent application number 13/556680 was filed with the patent office on 2013-01-31 for pump device.
This patent application is currently assigned to NIDEC SANKYO CORPORATION. The applicant listed for this patent is Tsutomu ARAI, Mitsuo YOKOZAWA. Invention is credited to Tsutomu ARAI, Mitsuo YOKOZAWA.
Application Number | 20130028761 13/556680 |
Document ID | / |
Family ID | 47573109 |
Filed Date | 2013-01-31 |
United States Patent
Application |
20130028761 |
Kind Code |
A1 |
YOKOZAWA; Mitsuo ; et
al. |
January 31, 2013 |
PUMP DEVICE
Abstract
A pump device may include a stator provided with a stator core
having a ring-shaped part on a center side and a drive coil wound
around the stator core, and a partition wall disposed configured to
separate a pump chamber from the stator. The partition wall is
provided with a protruded part in a bottomed tube-like shape which
is protruded on an inner side of the ring-shaped part and an outer
peripheral face of a tube shaped part structuring the protruded
part is formed with a plurality of protruding parts protruding to
an outer side in a radial direction. The stator core is fixed to
the protruded part in a state that the plurality of the protruding
parts is press-fitted to the ring-shaped part.
Inventors: |
YOKOZAWA; Mitsuo; (Nagano,
JP) ; ARAI; Tsutomu; (Nagano, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
YOKOZAWA; Mitsuo
ARAI; Tsutomu |
Nagano
Nagano |
|
JP
JP |
|
|
Assignee: |
NIDEC SANKYO CORPORATION
Nagano
JP
|
Family ID: |
47573109 |
Appl. No.: |
13/556680 |
Filed: |
July 24, 2012 |
Current U.S.
Class: |
417/410.1 |
Current CPC
Class: |
F04D 5/002 20130101;
F04D 29/628 20130101; F04D 13/0626 20130101; F04D 13/064
20130101 |
Class at
Publication: |
417/410.1 |
International
Class: |
F04B 35/04 20060101
F04B035/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 25, 2011 |
JP |
2011-162569 |
Claims
1. A pump device comprising: a stator comprising: a stator core
having a ring-shaped part on a center side; and a drive coil which
is wound around the stator core; a rotor provided with an impeller
and a drive magnet which faces the stator through a predetermined
distance on an outer peripheral side of the stator; and a partition
wall which is disposed between the stator and the rotor for
separating a pump chamber in which the impeller is disposed from
the stator; wherein the partition wall is provided with a protruded
part in a bottomed tube-like shape which is protruded on an inner
side of the ring-shaped part; wherein an outer peripheral face of a
tube shaped part structuring the protruded part is formed with a
plurality of protruding parts which protrude from parts in a
circumferential direction to an outer side in a radial direction;
and wherein the stator core is fixed to the protruded part in a
state that the plurality of the protruding parts is press-fitted to
the ring-shaped part.
2. The pump device according to claim 1, wherein an inner
peripheral face of the ring-shaped part of the stator core is
provided with a plurality of recessed parts to which each of the
plurality of the protruding parts is capable of being press-fitted,
and the protruding parts are press-fitted to the recessed
parts.
3. The pump device according to claim 2, wherein both side portions
in the circumferential direction of the protruding part are
press-fitted to the recessed part, and a clearance is provided
between a tip end on an outer side in the radial direction of the
protruding part and the recessed part.
4. The pump device according to claim 2, wherein the plurality of
the protruding parts is formed in a same shape as each other and is
formed at three or more positions at an equal angular interval.
5. The pump device according to claim 4, wherein the protruding
part is extended in an axial line direction along the outer
peripheral face of the tube shaped part and is provided with a
tapered face whose protruding amount to an outer side in the radial
direction and to the circumferential direction is increased from a
side of a bottom part of the protruded part in the bottomed
tube-like shape toward a side of an opening end of the protruded
part, and a part of the protruding part on the side of the opening
end is press-fitted to the ring-shaped part of the stator core.
6. The pump device according to claim 1, wherein the partition wall
is provided with a cylindrical tube part provided on an outer
peripheral side of the protruded part and a circular ring-shaped
part which connects an opening end of the protruded part with the
cylindrical tube part, the stator is accommodated in a circular
ring-shaped recessed part for accommodating the stator which is
formed of the protruded part, the cylindrical tube part and the
circular ring-shaped part, and the stator is covered by a sealing
agent which is poured into the circular ring-shaped recessed part
for accommodating the stator.
7. The pump device according to claim 6, wherein the protruded part
in the bottomed tube-like shape is provided with a protruding
portion which protrudes in an axial line direction from an opening
of the circular ring-shaped recessed part for accommodating the
stator on a bottom part side of the protruded part, and an end of
the protruding part on the bottom part side of the protruded part
is reached to the protruding portion.
8. The pump device according to claim 7, wherein the partition wall
is a resin molded product, and an inner peripheral face of the tube
shaped part structuring the protruded part is formed with a groove
at a position corresponding to the protruding part formed on the
outer peripheral face of the tube shaped part.
9. The pump device according to claim 8, wherein a support shaft
which rotatably supports the rotor is fixed to an inner side face
of the bottom part of the protruded part, the rotor is provided
with a bearing part in a tube-like shape, the bearing part is
disposed on an inner side of the protruded part in a state that the
support shaft is inserted into a center hole of the bearing part, a
washer for adjusting a position in the axial line direction of the
rotor is fitted between the bottom part of the protruded part and
the bearing part, the washer is formed with a turning prevention
part protruding to an outer side in the radial direction from an
outer circumferential edge portion of the washer, and the turning
prevention part is fitted to the groove formed on the inner
peripheral face of the tube shaped part.
10. The pump device according to claim 6, wherein a support shaft
which rotatably supports the rotor is fixed to an inner side face
of the bottom part of the protruded part.
11. The pump device according to claim 1, wherein an outer
peripheral face of the tube shaped part structuring the protruded
part is provided with a positioning part which is abutted with the
ring-shaped part of the stator core from a side of an opening end
of the protruded part in the bottomed tube-like shape for
positioning the stator in an axial line direction, and the
positioning part and the protruding part are formed at a separated
position from each other in a circumferential direction.
12. The pump device according to claim 1, wherein the pump device
comprises: a first case which structures the partition wall and is
provided with a circular ring-shaped protruded part on an inner
side of an outer peripheral wall; a second case which is provided
with a circular ring-shaped stepped part into which the circular
ring-shaped protruded part is coaxially inserted and which
partitions the pump chamber on an inner peripheral side of the
circular ring-shaped stepped part together with the first case; and
an O-ring which is attached on a circular outer peripheral face of
the circular ring-shaped protruded part and is crushed between the
circular outer peripheral face of the circular ring-shaped
protruded part and a circular inner peripheral face of the circular
ring-shaped stepped part in a direction perpendicular to an axial
line of the circular ring-shaped protruded part.
13. The pump device according to claim 12, wherein the first case
is provided with a cylindrical tube part formed on an outer
peripheral side of the protruded part and a circular ring-shaped
part connecting an opening end of the protruded part with the
cylindrical tube part, the stator is accommodated in a circular
ring-shaped recessed part for accommodating the stator which is
formed of the protruded part, the cylindrical tube part and the
circular ring-shaped part, and the stator is covered by a sealing
agent which is poured into the circular ring-shaped recessed part
for accommodating the stator.
14. The pump device according to claim 13, wherein the second case
comprises: a bottom plate part; a side wall part in a ring shape
which is stood up from an outer peripheral side portion of the
bottom plate part; and a circular recessed part which is formed of
the bottom plate part and the side wall part; an inner peripheral
face on an upper side of the side wall part is formed with the
circular ring-shaped stepped part; and a liquid flow passage is
structured between the circular ring-shaped protruded part of the
first case and the circular recessed part of the second case at a
position on an inner side with respect to the circular ring-shaped
stepped part.
15. A pump device comprising: a stator comprising: a stator core
having a ring-shaped part on a center side; and a drive coil which
is wound around the stator core; and a partition wall configured to
separate a pump chamber from the stator; wherein the partition wall
is provided with a protruded part in a bottomed tube-like shape
which is protruded on an inner side of the ring-shaped part;
wherein an outer peripheral face of a tube shaped part structuring
the protruded part is formed with a plurality of protruding parts
which protrude from parts in a circumferential direction to an
outer side in a radial direction; and wherein the stator core is
fixed to the protruded part in a state that the plurality of the
protruding parts is press-fitted to the ring-shaped part.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] The present invention claims priority under 35 U.S.C.
.sctn.119 to Japanese Application No. 2011-162569 filed Jul. 25,
2011, the entire content of which is incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] At least an embodiment of the present invention may relate
to a pump device which is provided with a partition wall
partitioning a pump chamber.
BACKGROUND
[0003] A vortex pump for pressure-feeding liquid is, for example,
disclosed in Japanese Patent Laid-Open No. 2010-119164. The pump
device disclosed in the literature is provided with a stator having
a stator core around which a drive coil is wound, a rotor having an
impeller and a drive magnet in a tube-like shape which surrounds
the stator from an outer peripheral side, and a partition wall
which is disposed between the stator and the rotor for separating
the pump chamber within which the impeller is disposed from the
stator. In the pump device disclosed in the literature, the stator
is fixed to a base plate through an insulator which is utilized
when the drive coil is wound around the stator core and then the
stator is fixed to a housing. The housing is a resin molded body in
which the stator and the base plate are resin-molded by insert
molding and a part of the resin molded body functions as the
partition wall.
[0004] In the pump device disclosed in the above-mentioned Patent
Literature, two members (insulator and base plate) are disposed
between the housing and the stator and thus dimensional tolerance
and assembling tolerance are accumulated and, as a result, the
positional accuracy of the stator with respect to the partition
wall may be lowered. When the positional accuracy of the stator
with respect to the partition wall is lowered, it is difficult to
control a gap between the stator having the drive coil and the
drive magnet of the rotor facing each other through the partition
wall and thus it is difficult to maintain the performance of a
manufactured pump device to be substantially the same.
SUMMARY
[0005] In view of the problem described above, at least an
embodiment of the present invention may advantageously provide a
pump device in which the stator is capable of being positioned and
fixed with a high degree of accuracy with respect to the partition
wall separating the stator from the rotor.
[0006] According to at least an embodiment of the present
invention, there may be provided a pump device including a stator
provided with a stator core having a ring-shaped part on a center
side and a drive coil which is wound around the stator core, a
rotor provided with an impeller and a drive magnet which faces the
stator through a predetermined distance on an outer peripheral side
of the stator, and a partition wall which is disposed between the
stator and the rotor for separating a pump chamber in which the
impeller is disposed from the stator. The partition wall is
provided with a protruded part in a bottomed tube-like shape which
is protruded on an inner side of the ring-shaped part, an outer
peripheral face of a tube shaped part structuring the protruded
part is formed with a plurality of protruding parts which protrude
from parts in a circumferential direction to an outer side in a
radial direction, and the stator core is fixed to the protruded
part in a state that a plurality of protruding parts is
press-fitted to the ring-shaped part.
[0007] According to at least an embodiment of the present
invention, the stator is directly fixed to the partition wall
separating the stator from the rotor. Therefore, positional
accuracy of the stator with respect to the partition wall can be
enhanced. Further, different from a case that the stator core is
fixed to the partition wall in a state that the entire periphery in
the circumferential direction of the protruded part is press-fitted
to the ring-shaped part, the stator core is fixed to the partition
wall in a state that a plurality of the protruding parts provided
on the outer peripheral face of the tube shaped part of the
protruded part is press-fitted to the ring-shaped part and thus a
press-fitting margin between the partition wall and the stator core
is small. As a result, the stator core is easily press-fitted when
the stator core is to be fixed to the partition wall and thus
positional accuracy of the stator with respect to the partition
wall can be enhanced even when the stator is press-fitted and fixed
to the partition wall. Therefore, a gap space between the stator
core of the stator and the drive magnet of the rotor which face
each other through the partition wall can be controlled with a high
degree of accuracy.
[0008] In accordance with at least an embodiment of the present
invention, an inner peripheral face of the ring-shaped part of the
stator core is provided with a plurality of recessed parts to which
each of a plurality of the protruding parts is capable of being
press-fitted, and the protruding parts are press-fitted to the
recessed parts. According to this structure, the stator (stator
core) is positioned around the axial line "L" by press-fitting the
protruding part to the recessed part. Further, when the rotor
provided with the impeller is rotated by the magnetic drive
mechanism structured of the drive coil, the stator core and the
drive magnet, the stator is prevented from being turned around the
axial line "L" by the reaction force. In addition, since a
plurality of the protruding parts provided on the outer peripheral
face of the protruded part is press-fitted to the recessed parts
provided in the ring-shaped part, stress at the time of
press-fitting is easily released from each of the protruding parts
to the circumferential direction of the protruded part. Therefore,
deformation and damage of the partition wall can be prevented when
the stator is press-fitted and fixed.
[0009] In this case, it is preferable that both side portions in
the circumferential direction of the protruding part are
press-fitted to the recessed part, and a clearance is provided
between a tip end on an outer side in the radial direction of the
protruding part and the recessed part. According to this structure,
stress is restrained from occurring in the radial direction of the
protruded part at the time of press-fitting and fixing. Therefore,
deformation and damage of the partition wall can be prevented.
[0010] In accordance with at least an embodiment of the present
invention, the plurality of the protruding parts is formed in the
same shape and is disposed at three or more positions at an equal
angular interval. According to this structure, when a plurality of
protruding parts is press-fitted to the ring-shaped part,
concentricity of the protruded part of the partition wall with the
stator core is improved and thus the positional accuracy of the
stator with respect to the partition wall is improved.
[0011] In accordance with at least an embodiment of the present
invention, the protruding part is extended in an axial line
direction along the outer peripheral face of the tube shaped part
and is provided with a tapered face whose protruding amount to an
outer side in the radial direction and to the circumferential
direction is increased from a side of a bottom part of the
protruded part in the bottomed tube-like shape toward a side of an
opening end of the protruded part, and a part of the protruding
part on the side of the opening end is press-fitted to the
ring-shaped part of the stator core. According to this structure,
the protruding part is easily press-fitted to the ring-shaped part
of the stator core. Further, only a part of the protruding part is
press-fitted to the ring-shaped part of the stator core and thus a
press-fitting margin can be reduced.
[0012] In accordance with at least an embodiment of the present
invention, the partition wall is provided with a cylindrical tube
part provided on an outer peripheral side of the protruded part and
a circular ring-shaped part which connects an opening end of the
protruded part with the cylindrical tube part, the stator is
accommodated in a circular ring-shaped recessed part for
accommodating the stator which is formed of the protruded part, the
cylindrical tube part and the circular ring-shaped part, and the
stator is covered by a sealing agent which is poured into the
circular ring-shaped recessed part for accommodating the stator.
According to this structure, even when a press-fitting margin
between the partition wall and the stator core is small, the stator
can be surely fixed to the partition wall by the sealing agent.
[0013] In this case, it is preferable that the protruded part in
the bottomed tube-like shape is provided with a protruding portion
which protrudes in an axial line direction from an opening of the
circular ring-shaped recessed part for accommodating the stator on
a bottom part side of the protruded part, and an end of the
protruding part on the bottom part side of the protruded part is
reached to the protruding portion. According to this structure, the
ends of the protruding parts which are reached to the protruding
portion are respectively fitted to the recessed parts of the
ring-shaped part of the stator core and, after that, the stator is
guided by the protruding parts and is accommodated in the stator
accommodating room.
[0014] Further, in this case, it is preferable that the partition
wall is a resin molded product, and an inner peripheral face of the
tube shaped part structuring the protruded part is formed with a
groove at a position corresponding to the protruding part formed on
the outer peripheral face of the tube shaped part. According to
this structure, a thickness of the tube shaped part of the
protruded part can be set almost uniform over the entire periphery
and thus shrinkage occurred in the protruded part when the
partition wall is molded can be set uniform. Therefore, the
cylindricality of the protruded part is improved.
[0015] In accordance with at least an embodiment of the present
invention, an outer peripheral face of the tube shaped part
structuring the protruded part is provided with a positioning part
which is abutted with the ring-shaped part of the stator core from
a side of an opening end of the protruded part in the bottomed
tube-like shape for positioning the stator in an axial line
direction, and the positioning part and the protruding part are
formed at a separated position from each other in a circumferential
direction. According to this structure, positioning of the stator
in the axial line direction is easily performed.
[0016] In accordance with at least an embodiment of the present
invention, a support shaft which rotatably supports the rotor is
fixed to an inner side face of the bottom part of the protruded
part. According to this structure, both of the support shaft
supporting the rotor and the stator are fixed to the protruded part
and thus a relative positional accuracy of the rotor supported by
the support shaft to the stator is improved.
[0017] Further, in accordance with at least an embodiment of the
present invention, a support shaft which rotatably supports the
rotor is fixed to an inner side face of the bottom part of the
protruded part, the rotor is provided with a bearing part in a
tube-like shape, the bearing part is disposed on an inner side of
the protruded part in a state that the support shaft is inserted
into a center hole of the bearing part, a washer for adjusting a
position in the axial line direction of the rotor is fitted between
the bottom part of the protruded part and the bearing part, the
washer is formed with a turning prevention part protruding to an
outer side in the radial direction from an outer circumferential
edge portion of the washer, and the turning prevention part is
fitted to the groove formed on the inner peripheral face of the
tube shaped part. According to this structure, a relative
positional adjustment of the rotor to the stator in the axial line
direction can be performed by fitting of the washer. Further, since
the turning prevention part and the groove are engaged with each
other, the washer is prevented from being turned around the axial
line when the rotor is rotated.
[0018] Further, the pump device in accordance with at least an
embodiment of the present invention may include a first case which
structures the partition wall and is provided with a circular
ring-shaped protruded part on an inner side of an outer peripheral
wall, a second case which is provided with a circular ring-shaped
stepped part into which the circular ring-shaped protruded part is
coaxially inserted and which partitions the pump chamber on an
inner peripheral side of the circular ring-shaped stepped part
together with the first case, and an O-ring which is attached on a
circular outer peripheral face of the circular ring-shaped
protruded part and is crushed between the circular outer peripheral
face of the circular ring-shaped protruded part and a circular
inner peripheral face of the circular ring-shaped stepped part in a
direction perpendicular to an axial line of the circular
ring-shaped protruded part.
[0019] Further, in accordance with at least an embodiment of the
present invention, the second case includes a bottom plate part, a
side wall part in a ring shape which is stood up from an outer
peripheral side portion of the bottom plate part, and a circular
recessed part which is formed of the bottom plate part and the side
wall part. An inner peripheral face on an upper side of the side
wall part is formed with the circular ring-shaped stepped part, and
a liquid flow passage is structured between the circular
ring-shaped protruded part of the first case and the circular
recessed part of the second case at a position on an inner side
with respect to the circular ring-shaped stepped part.
[0020] Other features and advantages of the invention will be
apparent from the following detailed description, taken in
conjunction with the accompanying drawings that illustrate, by way
of example, various features of embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Embodiments will now be described, by way of example only,
with reference to the accompanying drawings which are meant to be
exemplary, not limiting, and wherein like elements are numbered
alike in several Figures, in which:
[0022] FIGS. 1(a), 1(b) and 1(c) are perspective views and a front
view showing a pump device in accordance with an embodiment of the
present invention.
[0023] FIGS. 2(a) and 2(b) are cross-sectional views showing a pump
device in accordance with an embodiment of the present
invention.
[0024] FIG. 3 is an exploded perspective view showing a pump device
in accordance with an embodiment of the present invention.
[0025] FIG. 4(a) is a perspective view showing a rotor and FIG.
4(b) is a perspective view showing a stator.
[0026] FIGS. 5(a) and 5(b) are perspective views showing a lower
case.
[0027] FIGS. 6(a) and 6(b) are perspective views showing an upper
case.
[0028] FIGS. 7(a) and 7(b) are partly enlarged perspective views
showing a stator accommodating room of an upper case and the
like.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] A pump device in accordance with an embodiment of the
present invention will be described below with reference to the
accompanying drawings. In the following description, for
convenience of explanation, upper and lower sides of a pump device
are described according to an upper and lower direction in the
drawing. Further, a side from which a suction pipe and a discharge
pipe are protruded is referred to as a front side of the pump
device and its opposite side is referred to as a rear side and an
arrangement direction of the suction pipe and the discharge pipe is
referred to as a widthwise direction of the device.
[0030] (Entire Structure)
[0031] FIG. 1(a) is a perspective view showing a pump device in
accordance with an embodiment of the present invention which is
viewed from a forward oblique upper side, FIG. 1(b) is a
perspective view showing the pump device which is viewed from a
rearward oblique upper side, and FIG. 1 (c) is a front view showing
the pump device. A pump device 1 in accordance with an embodiment
of the present invention is a vortex pump which pressure-feeds
liquid such as refrigerant. The pump device 1 is provided with a
pump case 2 which is formed in a flat rectangular prism shape as a
whole. The pump case 2 is made of resin such as PPS (polyphenylene
sulfide). A suction pipe 3 and a discharge pipe 4 are protruded in
parallel toward the front side from a front face 2a of the pump
case 2. A wiring outlet part 6 for taking out lead wires 5 from an
inner side of the pump case 2 is provided at a corner portion 2b
located on a front left side between the front face 2a of the pump
case 2 and a side face adjacent to the front face 2a in a clockwise
direction. The lead wires 5 are extended out from a midway position
in an axial line "L" direction (height direction) of the pump
device 1 through the wiring outlet part 6 toward an obliquely front
side. The lead wires 5 are extended longer than the suction pipe 3
and the discharge pipe 4 and a connector 7 is attached to tip ends
of the lead wires 5.
[0032] An inclined face 2c (see FIG. 1(c)) intersecting the front
face 2a and the side face and extending in the axial line "L"
direction is formed at the corner portion 2b located on the front
left side of the pump case 2 where the wiring outlet part 6 is
provided by obliquely cutting out a tip end of the corner portion
2b. Further, a hook 8 is provided at the corner portion 2b located
on the front left side for locking the lead wires 5 when the lead
wires 5 are extended out along the inclined face 2c. The hook 8 is
extended in a direction perpendicular to the axial line "L" at a
center position in the axial line "L" direction of the inclined
face 2c so as to have a predetermined space between the inclined
face 2c and the hook 8. Further, the hook 8 is extended with a
constant width from the front face 2a side toward the side
face.
[0033] The pump case 2 is structured of a lower case (second case)
11 and an upper case (first case or partition wall) 12 which are
superposed on each other in the upper and lower direction. The
suction pipe 3 and the discharge pipe 4 are protruded from the
front face of the lower case 11. The wiring outlet part 6 is
structured at the corner portion on the front left side of the
upper case 12. The hook 8 is provided on the lower case 11. In this
embodiment, a corner portion 2f on the rear right side of the pump
case 2 which is located at a position diagonal to the wiring outlet
part 6 is provided with a turning prevention mechanism 13 for
preventing relative turning of the lower case 11 to the upper case
12 when the lower case 11 and the upper case 12 are superposed on
each other.
[0034] FIG. 2(a) is a longitudinal sectional view showing the pump
device 1 which is cut by the "X-X" line in FIG. 1(a) and FIG. 2(b)
is a longitudinal sectional view showing the pump device 1 which is
cut by the "Y-Y" line in FIG. 1(a). FIG. 3 is an exploded
perspective view showing the pump device 1. FIG. 4(a) is a
perspective view showing a rotor and FIG. 4(b) is a perspective
view showing a stator.
[0035] As shown in FIGS. 2(a) and 2(b) and FIG. 3, the lower case
11 and the upper case 12 are superposed on each other in a
partially overlapped state in a direction perpendicular to axial
line "L". A partitioned chamber 20 for accommodating a rotor and
for forming a pump chamber is structured between the lower case 11
and the upper case 12. A rotor 23 provided with a circular
ring-shaped impeller 21 and a drive magnet 22 and a support shaft
24 which rotatably supports the rotor 23 are disposed in the
partitioned chamber 20. Further, an outer peripheral side portion
of the partitioned chamber 20 is structured to be a circular
ring-shaped pump chamber 25 through which liquid is pressure-fed by
the impeller 21 and the impeller 21 structuring the rotor 23 is
disposed within the pump chamber 25. An O-ring 26 is disposed
between the lower case 11 and the upper case 12 for preventing
leakage of liquid from the partitioned chamber 20. A stator 29
provided with a drive coil 27 and a stator core 28 on which the
drive coil 27 is mounted and a base plate 30 are disposed on an
upper side of the upper case 12 which is opposite to the side where
liquid is pressure-fed, in other words, on an opposite side to the
partitioned chamber 20 with respect to the upper case 12 (opposite
side to the lower case 11). The drive magnet 22, the stator core
28, and the drive coil 27 wound around the stator core 28 structure
a magnetic drive mechanism for rotationally driving the impeller
21.
[0036] A liquid flow passage 31 is formed on a bottom face and a
ceiling face of the pump chamber 25 over a predetermined angular
range around the axial line "L". More specifically, a lower side
liquid flow passage 31a formed of a circular arc groove having a
semicircular cross-sectional shape is formed on the bottom face of
the pump chamber 25 which is structured of the lower case 11, and
an upper side liquid flow passage 31b formed of a circular arc
groove having a semicircular cross-sectional shape is formed on the
ceiling face of the pump chamber 25 which is structured of the
upper case 12. The lower side liquid flow passage 31a and the upper
side liquid flow passage 31b are superposed on each other when
viewed in the axial line "L" direction. In this embodiment, the
liquid flow passage 31 is formed over an angular range
approximately larger than 270.degree. around the axial line
"L".
[0037] In the pump chamber 25, a suction port 3a (see FIG. 5(a))
which is in communication with the suction pipe 3 is provided at a
portion of the lower case 11 where one end of the liquid flow
passage 31 is located and a discharge port 4a (see FIG. 5(a)) which
is in communication with the discharge pipe 4 is provided at a
portion of the lower case 11 where the other end of the liquid flow
passage 31 is located. A portion of the bottom face of the pump
chamber 25 which is located between the suction port 3a and the
discharge port 4a is formed as a lower side blocking part 32a where
the lower side liquid flow passage 31a is not formed. Similarly, a
portion of the ceiling face of the pump chamber 25 which is located
between the suction port 3a and the discharge port 4a is formed as
an upper side blocking part 32b where the upper side liquid flow
passage 31b is not provided.
[0038] A support shaft 24 is made of stainless steel and its lower
end portion is fixed to a support shaft fixing recessed part 60
which is provided in the lower case 11. Further, its upper end
portion is fixed to a support shaft fixing recessed part 82 which
is provided at a center of a bottom part 81 of a center protruded
part 80 formed in a bottomed tube-like shape that is provided at
the center portion of the upper case 12. The support shaft fixing
recessed part 82 is provided at a center of an inner side face of
the bottom part 81.
[0039] The rotor 23 is provided with, as shown in FIG. 4(a), a disk
part 40, a bearing part 41 in a cylindrical tube shape which is
protruded upward from a center of an upper face of the disk part
40, and a magnet holding cylindrical tube part 42 which is
protruded upward from the upper face of the disk part 40 so as to
coaxially surround the bearing part 41 with a predetermined
distance from the bearing part 41, which are made of resin such as
PPS. The predetermined distance between the bearing part 41 and the
cylindrical tube part 42 is a distance in which the stator 29 is
capable of being accommodated therebetween through the upper case
12. The rotor 23 is rotatable around the axial line "L" of the
support shaft 24 in a state that the support shaft 24 is inserted
into a center hole 41a of the bearing part 41 and the bearing part
41 is disposed on an inner side of the center protruded part 80 of
the upper case 12. One piece or plural pieces of the washer 43 is
fitted between an upper end of the bearing part 41 and the bottom
part 81 of the center protruded part 80 and the position of the
rotor 23 in the axial line "L" direction with respect to the stator
29 is adjusted by fitting of the washer 43 (see FIGS. 2(a) and
2(b)). In this embodiment, two pieces of the washer are used. For
example, when one or two pieces of a washer 43 whose thickness is
0.2 mm and a washer 43 whose thickness is 0.3 mm are selected, a
total thickness of the washers 43 can be adjusted in a range from
0.2 mm to 0.6 mm with an interval of 0.1 mm.
[0040] A yoke 44 in a cylindrical tube shape is held by an inner
peripheral face of the magnet holding cylindrical tube part 42 and
the drive magnet 22 in a cylindrical tube shape is held by an inner
peripheral face of the yoke 44. The yoke 44 is integrally formed
with the rotor 23 by insert molding and the drive magnet 22 is
adhesively fixed to the yoke 44. An outer peripheral portion on an
outer peripheral side in the disk part 40 with respect to the
cylindrical tube part 42 is structured as the impeller 21.
[0041] An outer peripheral portion of the impeller 21 is formed
with recessed parts 45 which are formed in two rows in the upper
and lower direction at an equal angular interval in the
circumferential direction. The recessed parts 45 are provided with
upper side recessed parts 46, which are formed by cutting a
circumferential edge of an upper face of the disk part 40 in a
circular arc shape, and lower side recessed parts 47 which are
formed by cutting a circumferential edge of an under face of the
disk part 40 in a circular arc shape. Portions between the recessed
parts 45 adjacent to each other in the circumferential direction
are formed as blades 48 which are respectively extended in a radial
direction. A portion between the upper side recessed parts 46 and
the lower side recessed parts 47 which are adjacent to each other
in the upper and lower direction is extended in the circumferential
direction and is formed to be a rib 49 partitioning the respective
blades 48 in the upper and lower direction. The impeller 21 is, as
shown in FIGS. 2(a) and 2(b), disposed in the pump chamber 25.
[0042] The stator 29 is disposed within a stator accommodating room
(stator accommodating circular ring-shaped recessed part) 83 which
is formed in a circular ring-shaped recessed part and is provided
on an outer peripheral side of the center protruded part 80 and on
an upper face side of the upper case 12. A stator core 28 is, as
shown in FIG. 4(b), provided with a ring-shaped part 50 on its
center side and a plurality of salient poles 51 which is protruded
from the ring-shaped part 50 to an outer side in the radial
direction. A drive coil 27 is wound around each of a plurality of
the salient poles 51. As shown in FIGS. 2(a) and 2(b), each of the
salient poles 51 is oppositely disposed through the upper case 12
in a direction perpendicular to the axial line "L" to the drive
magnet 22 of the rotor 23 which is disposed within the partitioned
chamber 20 that forms a magnet accommodating space in which the
circular ring-shaped drive magnet 22 is accommodated. The upper
case 12 is disposed between the rotor 23 and the stator 29 to be
functioned as a partition wall separating the pump chamber 25 and
the magnet accommodating space from the stator 29.
[0043] The stator core 28 is structured so that a plurality of
plate-shaped core pieces 52 having the same shape which are formed
by die cutting of a thin plate-shaped magnetic steel plate is
laminated in the upper and lower direction and a laminated
direction of the plate-shaped core pieces 52 is the axial line "L"
direction. An inner peripheral face of the ring-shaped part 50 of
the stator core 28 is formed with three inner side recessed parts
53 whose cross-sectional shape in a direction perpendicular to the
axial line "L" is a circular arc contour shape at an equal angular
interval around the axial line "L". Three inner side recessed parts
53 are the same shape and are extended in the axial line "L"
direction. The depths in the radial direction of the respective
inner side recessed parts 53 are the same as each other and its
cross-sectional shape is the same as each other at each position in
the axial line "L" direction.
[0044] A base plate 30 is disposed in an upper space 87 which is
provided on an inner side of a frame-shaped outer peripheral wall
86 protruding from an upper face of the upper case 12 to an upper
side along its circumferential edge. The base plate 30 serves as a
circuit board for supplying an electric current to the drive coil
27 wound around the stator core 28 and covers the stator 29
disposed within the stator accommodating room 83 from the upper
side. A face on the stator core 28 side of the base plate 30 is
connected with the lead wires 5, which are drawn out to an outer
side of the pump case 2 through the wiring outlet part 6. The
wiring outlet part 6 is, as shown in FIG. 3, provided with a wiring
outlet port 33 which is formed by cutting out an outer peripheral
wall 86, a wire placing part 34 for arranging and placing the lead
wires 5 in one row which are drawn out from the inner side of the
pump case 2 to the outer side through the wiring outlet port 33,
and a fixing member 35 which is fixed to the upper case 12 so as to
close the wiring outlet port 33 from the upper side of the base
plate 30 for sandwiching the lead wires 5 arranged on the wire
placing part 34 between the wire placing part 34 and the fixing
member 35 and thereby their coatings are fixed in a pressed
state.
[0045] In this embodiment, as shown in FIGS. 1(a) and 1(b), a
potting agent 16 (sealing agent) is poured into the stator
accommodating room 83 and the upper space 87 of the upper case 12
so as to reach the upper end of the outer peripheral wall 86 and
thus the stator 29 and the base plate 30 are covered and fixed by
the potting agent 16. The potting agent 16 is resin having
insulation property such as epoxy, acrylic, or silicon resin.
[0046] When an exciting current is supplied to the drive coil 27
from the connector 7 through the lead wires 5 and the base plate
30, the rotor 23 is rotated around the axial line "L". As a result,
liquid is sucked into the pump chamber 25 through the suction pipe
3, pressurized in the pump chamber 25 and then discharged from the
discharge pipe 4. The motor (rotor 23, stator 29 and base plate 30)
which drives the pump device 1 in this embodiment is a three-phase
brushless motor and three Hall elements not shown for detecting a
position of the drive magnet 22 of the rotor 23 are disposed on the
base plate 30. When the order of an exciting current supplied to
the drive coil 27 is reversed, the rotor 23 is rotated in the
reverse direction and thus, liquid is sucked through the discharge
pipe 4, pressurized in the pump chamber 25 and then discharged from
the suction pipe 3.
[0047] (Lower Case)
[0048] FIG. 5(a) is a perspective view showing the lower case 11
which is viewed from an upper side and FIG. 5(b) is a perspective
view showing the lower case 11 which is viewed from a lower side.
The lower case 11 is provided with a bottom plate part 61, a ring
shaped side wall part 62 which is stood up from an outer peripheral
side portion of the bottom plate part 61 so as to extend to an
upper side, and a circular recessed part 63 which is formed by the
bottom plate part 61 and the side wall part 62. A contour shape of
the side wall part 62 which is viewed in the axial line "L"
direction is a substantially rectangular shape and a planar shape
of the lower case 11 viewed in the axial line "L" direction is a
substantially rectangular shape. The side wall part 62 is provided
with a flat upper end face 62a and the upper end face 62a is an
upper end face of the lower case 11. The pump chamber 25 is
structured so as to be a ring shape along the circumferential edge
of the circular recessed part 63. A support shaft fixing recessed
part 60 is provided at the center of a circular bottom face of the
circular recessed part 63.
[0049] A circular ring-shaped recessed part 64 is formed on an
outer peripheral side of the support shaft fixing recessed part 60
coaxially with the support shaft fixing recessed part 60. A portion
between the support shaft fixing recessed part 60 and the circular
ring-shaped recessed part 64 is formed to be an inner side
ring-shaped protruded face 65 and a portion on an outer peripheral
side of the circular ring-shaped recessed part 64 is formed to be
an outer side ring-shaped protruded face 66. The outer side
ring-shaped protruded face 66 structuring the circular recessed
part 63 is formed with a lower side liquid flow passage 31a
structuring a bottom face of the pump chamber 25 and a lower side
blocking part 32a along its circumferential edge. A circular
ring-shaped end face portion 67 of the outer side ring-shaped
protruded face 66 which is adjacent to the inner side of pump
chamber 25 faces the disk part 40 of the rotor 23 which is disposed
within the partitioned chamber 20 through a minute gap "G1" (see
FIGS. 2(a) and 2(b)). In the circular ring-shaped end face portion
67, two grooves 67a having a constant width by which the lower side
liquid flow passage 31a is in communication with the circular
ring-shaped recessed part 64 are formed at positions separated from
each other by 180.degree.
[0050] A circular ring-shaped stepped part 68 is provided on an
upper side portion of the circular recessed part 63, in other
words, on an inner peripheral face of an upper side portion of the
side wall part 62. The circular ring-shaped stepped part 68 is
provided with a circular ring-shaped end face 68a, which is
extended in a radial direction from a midway position in the axial
line "L" direction of the inner peripheral face of the side wall
part 62, and a circular inner peripheral face 68b which is extended
to an upper side from an outer circumferential edge of the circular
ring-shaped end face 68a. The circular ring-shaped stepped part 68
forms a circular recessed part having a diameter larger than a
circular recessed part 63 on an upper end portion of the lower case
11.
[0051] The suction pipe 3 and the discharge pipe 4 are protruded in
parallel from the front face of the side wall part 62. An inclined
face 2c and a hook 8 are provided at the corner portion 2b of the
lower case 11 on the front left side which is adjacent to the
discharge pipe 4 of the side wall part 62. A turning prevention
recessed part 69 structuring the turning prevention mechanism 13 is
provided at a corner portion 2f on the rear right side of the side
wall part 62. The turning prevention recessed part 69 is a recessed
part which is recessed to a lower side from the upper end face 62a.
Further, the turning prevention recessed part 69 is cut out from
the outer peripheral side and its inner peripheral face is exposed
to the outer side of the lower case 11.
[0052] (Upper Case)
[0053] FIG. 6(a) is a perspective view showing the upper case 12
which is viewed from an upper side and FIG. 6(b) is a perspective
view showing the upper case 12 which is viewed from a lower side.
The upper case 12 is, as shown in FIG. 6(a), provided with a center
protruded part 80 to which the ring-shaped part 50 of the stator
core 28 is fitted, a cylindrical tube part 89, which is coaxially
structured with the center protruded part 80 and with which the
outer peripheral faces of the salient poles 51 of the stator core
28 are abutted, and an inner side ring-shaped part 90 which
connects an opening end of the center protruded part 80 with a
lower end part of the cylindrical tube part 89. Further, the upper
case 12 is, as shown in FIG. 6(b), provided with a circular
ring-shaped protruded part 91, which is coaxially structured with
the center protruded part 80 and the cylindrical tube part 89 on an
outer peripheral side of the cylindrical tube part 89 and is
protruded to a lower side, an outer side ring-shaped part 92, which
connects an upper end part of the cylindrical tube part 89 with an
upper end part of the circular ring-shaped protruded part 91, and a
projecting part 93 which projects from an upper end part of the
circular ring-shaped protruded part 91 to an outer peripheral
side.
[0054] A contour shape of the projecting part 93 is a roughly
rectangular shape and the corner portion 2b on the front left side
is cut out obliquely to form the inclined face 2c. The outer
peripheral wall 86 for partitioning an upper space 87 in which the
base plate 30 is disposed is protruded to the upper side from an
outer circumferential edge of the projecting part 93 except the
corner portion 2b on the front left side which is provided with the
cut-out portion. In the corner portion 2b on the front left side
having the cut-out portion, the outer peripheral wall 86 is located
at an inner position from an outer circumferential edge of the
projecting part 93. Further, in the corner portion 2b on the front
left side, the outer peripheral wall 86 is cut out with a constant
width in a rectangular shape and the cut-out part is formed as the
wiring outlet port 33. A portion between the wiring outlet port 33
and the outer circumferential edge of the projecting part 93 is the
wire placing part 34. An upper face of the wire placing part 34 is
formed with wire holding grooves 36a whose cross section is a
circular arc shape and which are extended in parallel to an outer
side in the radial direction so as to correspond to the number of
the lead wires 5. Further, an under face of the fixing member 35 is
formed with wire holding grooves 36b corresponding to the wire
holding grooves 36b (see FIG. 1(c)). The lead wires 5 are
sandwiched between the wire holding grooves 36a and the wire
holding grooves 36b in the upper and lower direction and are fixed
in a state that their coatings are pressed.
[0055] The corner portion 2f on the rear right side of the
projecting part 93 located at a diagonal position to the wiring
outlet part 6 is formed with a turning preventing protruded part 97
in a circular cylindrical shape which is protruded to the lower
case 11 side. The turning preventing protruded part 97 is capable
of being fitted to the turning prevention recessed part 69 provided
in the lower case 11 and structures the turning prevention
mechanism 13 together with the turning prevention recessed part
69.
[0056] The stator accommodating room 83 in which the stator 29 is
disposed is structured of faces of the center protruded part 80,
the cylindrical tube part 89 and the inner side ring-shaped part 90
on an opposite side with respect to the lower case 11. The center
protruded part 80 is provided with a protruding portion 80a, which
is protruded to an upper side from an opening of the stator
accommodating room 83, on a side of the bottom part 81. A thickness
in the radial direction of the cylindrical tube part 89 is formed
thinner than a thickness in the radial direction of the center
protruded part 80.
[0057] A circular ring-shaped lower end face 94 of the circular
ring-shaped protruded part 91 is formed with an upper side liquid
flow passage 31b and an upper side blocking part 32b, which
structures a ceiling face of the pump chamber 25, at a midway
position in the radial direction on an inner side with respect to
the circular ring-shaped stepped part 68. In the circular
ring-shaped lower end face 94, a circular ring-shaped end face
portion 94a which is adjacent to an inner side of the pump chamber
25 faces the disk part 40 of the rotor 23 disposed within the
partitioned chamber 20 through a minute gap "G2" (see FIGS. 2(a)
and 2(b)2).
[0058] A radial direction protruded part 96 protruding to an outer
side by a predetermined dimension in the radial direction is
provided on an upper end portion of a circular outer peripheral
face 95 of the circular ring-shaped protruded part 91. The radial
direction protruded part 96 is provided with a circular ring-shaped
end face 96a, which is extended to an outer side in the radial
direction from a midway position in the axial line "L" direction of
the circular ring-shaped protruded part 91 so as to face the lower
case 11, and a circular outer peripheral face 96b which is extended
to an upper side from an outer circumferential edge of the circular
ring-shaped end face 96a so as to face the outer side in the radial
direction.
[0059] In this embodiment, when the upper case 12 and the lower
case 11 are to be superposed on each other to partition the pump
chamber 25 (partitioned chamber 20), an O-ring 26 is mounted on the
circular outer peripheral face 95 of the circular ring-shaped
protruded part 91 of the upper case 12. In this case, a lubricant
is applied to the O-ring 26. Further, the support shaft 24 is
previously fixed to the support shaft fixing recessed part 82 of
the upper case 12 and the rotor 23 is disposed in the circular
recessed part 63 of the lower case 11 so that the support shaft 24
is capable of being inserted into the bearing part 41. Next, the
circular ring-shaped protruded part 91 of the upper case 12 is
inserted into the inner side of the circular ring-shaped stepped
part 68 of the lower case 11. After that, the upper case 12 and the
lower case 11 are relatively come close to each other so that the
circular ring-shaped lower end face 94 of the circular ring-shaped
protruded part 91 (circular ring-shaped end face portion which is
located on the outer peripheral side with respect to the upper side
liquid flow passage 31b and the upper side blocking part 32b) is
abutted with the circular ring-shaped end face 68a of the circular
ring-shaped stepped part 68 of the lower case 11.
[0060] In this case, the circular outer peripheral face 96b of the
radial direction protruded part 96 of the upper case 12 is abutted
with the circular inner peripheral face 68b of the circular
ring-shaped stepped part 68 of the lower case 11 and thus the upper
case 12 is positioned in the radial direction by the lower case 11.
Further, the O-ring 26 is crushed in the radial direction between
the circular outer peripheral face 95 of the circular ring-shaped
protruded part 91 of the upper case 12 and the circular inner
peripheral face 68b of the lower case 11 in a sandwiched state
between the circular ring-shaped end face 96a of the radial
direction protruded part 96 and the circular ring-shaped end face
68a of the circular ring-shaped stepped part 68. As a result, the
leakage of liquid from the partitioned chamber 20 is prevented. In
this embodiment, when the circular ring-shaped protruded part 91 of
the upper case 12 is inserted into an inner side of the circular
ring-shaped stepped part 68 of the lower case 11, the turning
preventing protruded part 97 of the turning prevention mechanism 13
is fitted to the turning prevention recessed part 69 provided in
the lower case 11 and thus the lower case 11 and the upper case 12
are prevented from being relatively turned to each other around the
axial line "L". Therefore, the O-ring 26 is prevented from being
twisted in the circumferential direction in a state that the O-ring
26 is crushed in the radial direction and thus, when the pump
chamber 25 is to be partitioned, the damage of the O-ring 26 is
prevented. When the upper case 12 is superposed on the lower case
11 to form the pump chamber 25 (partitioned chamber 20) in a
partitioned state, the lower end of the support shaft 24 penetrated
through the bearing part 41 of the rotor 23 is inserted and fixed
to the support shaft fixing recessed part 60 of the lower case 11
and the support shaft 24 and the center protruded part 80 are set
to be in a coaxial state. Further, the rotor 23 is supported by the
support shaft 24 in a rotatable state around the support shaft
24.
[0061] The tube shaped part 84 structuring the center protruded
part 80 is provided with an outer peripheral face and an inner
peripheral face which are formed in a tapered shape whose diameter
is enlarged from a side of the bottom part 81 toward a side of an
opening end 80b along the axial line "L" direction. The outer
peripheral face of the tube shaped part 84 is formed with three
stator fixing protruding parts 85 which are protruded to outer
sides in a radial direction from parts in the circumferential
direction. The three stator fixing protruding parts 85 are provided
with the same shape and are formed at an equal angular interval
around the axial line "L". Each of the stator fixing protruding
parts 85 is formed so that its cross section perpendicular to the
axial line "L" is a circular arc contour shape and is extended in
the axial line "L" direction along the outer peripheral face of the
center protruded part 80. Further, each of the stator fixing
protruding parts 85 is provided with a tapered face whose
protruding amount to an outer side in the radial direction and in
the circumferential direction is increased from a side of the
bottom part 81 toward a side of the opening end, in other words,
from the upper side to the lower side. An upper end 85a on the
bottom part 81 side of each of the three stator fixing protruding
parts 85 is reached to a protruding portion 80a which protrudes in
the center protruded part 80 upward from the opening of the stator
accommodating room 83, and a lower end of each of the three stator
fixing protruded parts 85 on the inner side ring-shaped part 90
side is reached downward with respect to a positioning part 88
described below.
[0062] Further, the outer peripheral face of the tube shaped part
84 of the center protruded part 80 is formed with a positioning
part 88 so as to be abutted with the ring-shaped part 50 of the
stator core 28 from the underside in the axial line "L" direction
to position the stator core 28 in the axial line "L" direction. The
positioning part 88 is a protruded part in a circular arc shape
which is extended in a circumferential direction along the outer
peripheral face of the tube shaped part 84 and is provided at three
positions in the circumferential direction. An upper end face of
the positioning part 88 which is abutted with the stator core 28 is
a flat face which is perpendicular to the axial line "L". The
positioning part 88 and the stator fixing protruding part 85 are
formed at a separated position in the circumferential direction and
a gap space 88a is provided between the positioning part 88 and the
stator fixing protruded part 85 in the circumferential direction.
Three pieces of a plate-shaped rib 98 are provided between the
positioning part 88 and the cylindrical tube part 89 so as to
extend in a radial direction and connect the positioning part 88
with the cylindrical tube part 89. Strength of the stator
accommodating room 83 of the upper case 12 is assured by the ribs
98.
[0063] An inner peripheral face of the tube shaped part 84 of the
center protruded part 80 is formed with three grooves 99 extending
in the axial line "L" direction at corresponding positions to the
respective stator fixing protruding parts 85 formed on the outer
peripheral face of the tube shaped part 84. In other words, the
inner peripheral face of the tube shaped part 84 of the center
protruded part 80 is formed with three grooves 99 having the same
shape at an equal angular interval around the axial line "L" of the
support shaft 24. The cross-sectional shape perpendicular to the
axial line "L" of each of the grooves 99 is semicircular and the
groove 99 is extended in the axial line "L" direction along the
inner peripheral face of the center protruded part 80. Further, a
width in the circumferential direction of each of the grooves 99 is
gradually increased from a side of the bottom part 81 toward a side
of the opening end 80b.
[0064] (Fixing Structure of Stator)
[0065] FIGS. 7(a) and 7(b) are partly enlarged views showing a
stator accommodating room of an upper case and the like. FIG. 7(a)
is a view showing a state that the stator 29 is not accommodated in
the stator accommodating room and FIG. 7(b) is a view showing a
state that the stator 29 is accommodated in the stator
accommodating room. After the drive coil 27 is wound around each of
the salient poles 51, the stator core 28 is fixed to the inside of
the stator accommodating room 83 of the upper case 12. More
specifically, in a state that the stator fixing protruding part 85
is fitted to the inner side recessed part 53 of the ring-shaped
part 50 of the stator core 28, the stator 29 is inserted into the
stator accommodating room 83 and, after that, the lower end portion
85b of the stator fixing protruding part 85 (part on the opening
end 80b side of the center protruded part 80) is press-fitted to
the inner side recessed part 53 of the ring-shaped part and thereby
the stator 29 is fixed to the upper case 12. In this embodiment, a
diameter on an inner side of the ring-shaped part 50 of the stator
core 28 is larger than that of the tube shaped part 84 of the
center protruded part 80 and thus, a gap space is structured
between the inner side of the ring-shaped part 50 and the tube
shaped part 84 except the portions of the stator fixing protruding
parts 85. Further, a curvature of the inner side recessed part 53
of the ring-shaped part 50 of the stator core 28 is larger than
that of the lower end portion 85b of the stator fixing protruding
part 85 and thus only a tip end part of the lower end portion 85b
of the stator fixing protruding part 85 is press-fitted to the
bottom part of the inner side recessed part 53 of the ring-shaped
part 50. In other words, a gap space is formed between the side
faces in the circumferential direction of the lower end portion 85b
and the inner side recessed part 53.
[0066] In this embodiment, the upper end 85a on the bottom part 81
side of the stator fixing protruding part 85 is reached to the
protruding portion 80a of the center protruded part 80 which is
protruded upward from the opening of the stator accommodating room
83. Therefore, when the stator 29 is to be fitted to the stator
accommodating room 83, the upper end 85a of each of the stator
fixing protruding parts 85 is easily fitted to the inner side
recessed part 53 of the ring-shaped part 50 of the stator core 28.
Further, the stator fixing protruding part 85 is formed in a
tapered face which is widened toward the lower side and thus, when
the stator 29 is inserted into the stator accommodating room 83, at
first, the stator 29 is guided to a lower side by the stator fixing
protruding parts 85. Then, the positioning part 88 is abutted with
the ring-shaped part 50 of the stator core 28 from the underside to
position the stator 29 in the axial line "L" direction. Further,
the upper end faces of the positioning parts 88 are abutted with
the stator core 28 and thus the attitude of the stator core 28 is
determined. In this embodiment, the stator 29 is positioned and
fixed in a state that the lower end portions 85b of the stator
fixing protruding parts 85 are press-fitted to the inner side
recessed parts 53 of the ring-shaped part 50 of, for example, one
piece of the plate-shaped core piece 52 structuring the stator core
28.
[0067] When the stator 29 is fixed to the inside of the stator
accommodating room 83 of the upper case 12, the salient poles 51 of
the stator core 28 around which the drive coil 27 is wound and the
drive magnet 22 of the rotor 23 which is disposed in the
partitioned chamber 20 are faced each other through the tube shaped
part 84 of the upper case 12. In this state, a potting agent 16 is
poured into the stator accommodating room 83. The potting agent 16
is flowed into a space structured between the inner side face of
the ring-shaped part 50 and the tube shaped part 84 and thereby the
stator 29 is covered by the potting agent 16.
[0068] In this embodiment, as shown in FIGS. 2(a) and 2(b), one or
plural washers 43 are fitted between the upper end face of the
bearing part 41 of the rotor 23 and the bottom part 81 of the
protruded part and thereby the magnetic center position in the
axial line "L" direction of the drive magnet 22 mounted on the
rotor 23 is shifted to a lower side with respect to the magnetic
center position in the axial line "L" direction of the stator core
28. As a result, the rotor 23 is urged upward by a magnetic
attraction force acted between the stator core 28 and the drive
magnet 22. In this embodiment, turning prevention parts 43a in a
semicircular shape are formed in each of the washers 43 so as to
protrude to an outer side in the radial direction from its outer
circumferential edge portion. Further, each of the turning
prevention parts 43a is fitted to each of the grooves 99 formed on
the inner peripheral face of the center protruded part 80 and
thereby the washer 43 is prevented from being turned around the
axial line "L" when the rotor 23 is rotated. Further, as described
above, one or two pieces of the washers 43 whose thickness is 0.2
mm and 0.3 mm are selectively used. In this case, when two turning
prevention parts 43a are provided in the washer 43 whose thickness
is 0.2 mm and three turning prevention parts 43a are provided in
the washer 43 whose thickness is 0.3 mm, the washer 43 whose
thickness is 0.2 mm and the washer 43 whose thickness is 0.3 mm are
easily distinguished from each other.
[0069] (Operation and Effect)
[0070] According to this embodiment, the stator 29 is directly
fixed to the upper case 12 (partition wall or first case) which
partitions the stator 29 from the rotor 23. Therefore, positional
accuracy of the stator 29 with respect to the upper case 12
(partition wall) can be enhanced. Further, different from a case
that the stator core 28 is fixed to the upper case 12 in a state
that the entire periphery in the circumferential direction of the
center protruded part 80 is press-fitted to the ring-shaped part 50
of the stator 29, in this embodiment, the stator core 28 is fixed
to the upper case 12 in a state that three stator fixing protruding
parts 85 provided on the outer peripheral face of the tube shaped
part 84 of the center protruded part 80 are press-fitted to the
ring-shaped part 50 and thus a press-fitting margin between the
upper case 12 and the stator core 28 is small. As a result, the
stator core 28 is easily press-fitted when the stator core 28 is to
be fixed to the upper case 12 and thus positional accuracy of the
stator 29 with respect to the upper case 12 can be enhanced even
when the stator 29 is press-fitted and fixed to the upper case 12.
Therefore, a gap space between the stator core 28 of the stator 29
and the drive magnet 22 of the rotor 23 which face each other
through the upper case 12 (partition wall) can be controlled with a
high degree of accuracy.
[0071] Further, the inner peripheral face of the ring-shaped part
50 of the stator core 28 is formed with a plurality of inner side
recessed parts 53 to which each of three stator fixing protruding
parts 85 is capable of being press-fitted and each of the stator
fixing protruding parts 85 is press-fitted to each of the inner
side recessed parts 53. Therefore, the stator 29 (stator core 28)
is positioned around the axial line "L". Further, when the rotor 23
provided with the impeller 21 is rotated by the magnetic drive
mechanism structured of the drive coil 27, the stator core 28 and
the drive magnet 22, the stator 29 is prevented from being turned
around the axial line "L" by the reaction force. In addition, in
this embodiment, three stator fixing protruding parts 85 provided
on the outer peripheral face of the center protruded part 80 are
press-fitted to the inner side recessed parts 53 of the ring-shaped
part 50 and thus stress at the time of press-fitting is easily
released from each of the stator fixing protruding parts to the
circumferential direction of the center protruded part 80.
Therefore, deformation and damage of the upper case 12 can be
prevented when the stator 29 is press-fitted and fixed.
[0072] In addition, three stator fixing protruding parts 85 are
provided with the same shape as each other and three or more stator
fixing protruding parts 85 may be formed at an equal angular
interval. Therefore, when three stator fixing protruding parts 85
are press-fitted and fixed to the ring-shaped part 50,
concentricity of the center protruded part 80 of the upper case 12
with the stator core 28 is improved. Accordingly, the positional
accuracy of the stator 29 with respect to the upper case 12 is
improved.
[0073] Further, in this embodiment, the stator 29 is covered by the
potting agent 16 as a sealing agent which is poured into the stator
accommodating room 83 and thus, even when a press-fitting margin
between the upper case 12 and the stator core 28 is small, the
stator 29 can be surely fixed to the upper case 12 by the potting
agent 16.
[0074] In addition, in this embodiment, the inner peripheral face
of the tube shaped part 84 of the center protruded part 80 is
formed with the groove 99 at a position corresponding to each of
the stator fixing protruding parts 85 formed on the outer
peripheral face of the tube shaped part 84. Therefore, a thickness
of the tube shaped part 84 of the center protruded part 80 can be
set almost uniform over the entire periphery. As a result,
shrinkage occurred in the center protruded part 80 when the upper
case 12 is molded can be set uniform and thus the cylindricality of
the center protruded part 80 is improved.
[0075] Further, in this embodiment, the positioning part 88 and the
stator fixing protruding parts 85 are formed at separated positions
in the circumferential direction and thus, even when the
ring-shaped part 50 of the stator core 28 shaves the stator fixing
protruding parts 85 made of resin at the time of press-fitting,
shavings are not attached to the positioning part 88. Therefore,
positioning in the axial line "L" direction of the stator 29 can be
performed with a high degree of accuracy.
[0076] In addition, in this embodiment, the support shaft 24
rotatably supporting the rotor 23 is fixed to the center of the
inner side face of the bottom part 81 (face on the partitioned
chamber 20 side) of the center protruded part 80 to which the
stator core 28 is fixed. Therefore, a relative positional accuracy
of the rotor 23 supported by the support shaft 24 to the stator 29
is improved. Further, according to this structure, the support
shaft 24 is fixed to the bottom part 81 of the center protruded
part 80 and the stator core 28 is fixed to the opening end 80b side
of the center protruded part 80 and thus the fixed part of the
stator 29 and the fixed part of the support shaft 24 are separated
from each other in the axial line "L" direction. Therefore, even
when the tube shaped part 84 of the center protruded part 80 may be
deformed at the time of press-fitting and fixing of the stator 29,
the fixing of the support shaft 24 is prevented from being
unstable.
Other Embodiments
[0077] In the embodiment described above, each of the stator fixing
protruding parts 85 and each of the inner side recessed parts 53
are provided with a circular arc contour in cross section and the
tip end on the outer peripheral side of the stator fixing
protruding part 85 is press-fitted to the inner side recessed part
53 and gap spaces are provided both sides in the circumferential
direction. However, for example, it may be structured that one of
the cross-sectional shapes of the stator fixing protruding part 85
and the inner side recessed part 53 is changed and both sides in
the circumferential direction of the stator fixing protruding part
85 are press-fitted to the inner side recessed part 53 and a
clearance is provided between the tip end on the outer side in the
radial direction and the inner side recessed part 53. In this case,
at the time of press-fitting, stress is restrained to occur the
center protruded part 80 in the radial direction and thus
deformation and damage of the upper case 12 can be prevented. In
accordance with an embodiment of the present invention, no inner
side recessed part 53 which is provided in the ring-shaped part 50
of the stator core 28 may be formed. Further, in a case that the
entire periphery on the outer peripheral side of the stator fixing
protruding part 85 is press-fitted to the inner side recessed part
53, positioning in the circumferential direction and the radial
direction of the stator 29 are performed simultaneously. In
addition, the cross sectional shapes of each of the stator fixing
protruding part 85 and each of the inner side recessed part 53 are
not limited to a semicircular shape and a triangular shape and a
quadrangular shape may be used.
[0078] While the description above refers to particular embodiments
of the present invention, it will be understood that many
modifications may be made without departing from the spirit
thereof. The accompanying claims are intended to cover such
modifications as would fall within the true scope and spirit of the
present invention.
[0079] The presently disclosed embodiments are therefore to be
considered in all respects as illustrative and not restrictive, the
scope of the invention being indicated by the appended claims,
rather than the foregoing description, and all changes which come
within the meaning and range of equivalency of the claims are
therefore intended to be embraced therein.
* * * * *