U.S. patent application number 15/969874 was filed with the patent office on 2018-08-30 for air blowing apparatus and vacuum cleaner.
The applicant listed for this patent is Nidec Corporation. Invention is credited to Ryosuke HAYAMITSU, Yuzo MIYAMOTO, Satoshi UEDA.
Application Number | 20180245601 15/969874 |
Document ID | / |
Family ID | 58695209 |
Filed Date | 2018-08-30 |
United States Patent
Application |
20180245601 |
Kind Code |
A1 |
HAYAMITSU; Ryosuke ; et
al. |
August 30, 2018 |
AIR BLOWING APPARATUS AND VACUUM CLEANER
Abstract
An air blowing apparatus according to an embodiment of the
disclosure includes: a motor including a shaft extending vertically
along a central axis; an impeller fixed to the shaft; and an
impeller cover surrounding an upper and an outer side in a radial
direction of the impeller and including a suction inlet at a
center. The impeller includes multiple movable vanes, a lower
shroud, and an upper shroud including a first raised portion and a
second raised portion. A clearance in the axial direction between a
lower surface of the impeller cover and at least one of the first
and the second raised portion is smaller than a clearance in the
axial direction between the lower surface of the impeller cover and
the upper shroud on the inner side in the radial direction of the
first raised portion.
Inventors: |
HAYAMITSU; Ryosuke; (Kyoto,
JP) ; MIYAMOTO; Yuzo; (Kyoto, JP) ; UEDA;
Satoshi; (Kyoto, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nidec Corporation |
Kyoto |
|
JP |
|
|
Family ID: |
58695209 |
Appl. No.: |
15/969874 |
Filed: |
May 3, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2016/083017 |
Nov 8, 2016 |
|
|
|
15969874 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04D 17/16 20130101;
F04D 25/08 20130101; F04D 29/662 20130101; F04D 25/0613 20130101;
F04D 29/281 20130101; A47L 5/22 20130101; H02K 1/30 20130101; H02K
7/04 20130101; H02K 7/085 20130101; H02K 1/2786 20130101; A47L 9/00
20130101; F04D 29/4206 20130101; H02K 5/225 20130101; H02K 7/14
20130101; F04D 29/287 20130101; F04D 25/06 20130101; F04D 29/162
20130101; F04D 29/4253 20130101 |
International
Class: |
F04D 29/28 20060101
F04D029/28; A47L 5/22 20060101 A47L005/22; F04D 29/42 20060101
F04D029/42; F04D 29/16 20060101 F04D029/16; F04D 29/66 20060101
F04D029/66; F04D 25/08 20060101 F04D025/08; F04D 25/06 20060101
F04D025/06 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 9, 2015 |
JP |
2015-219104 |
Claims
1. An air blowing apparatus comprising: a motor which includes a
shaft disposed along a central axis extending vertically; an
impeller which is fixed to the shaft; and an impeller cover which
surrounds an upper side and an outer side in a radial direction of
the impeller and which includes a suction inlet at a center,
wherein the impeller includes a plurality of movable vanes which
are disposed in a circumferential direction, a lower shroud which
is disposed on the lower side of the movable vanes, an upper shroud
which is disposed on the upper side of the movable vanes and which
includes a through hole penetrating in an axial direction, the
upper shroud includes a first raised portion which protrudes upward
from an upper surface of the upper shroud and which extends in the
circumferential direction, a second raised portion which is
disposed on the outer side in the radial direction of the first
raised portion, which protrudes upward from the upper surface of
the upper shroud, and which extends in the circumferential
direction, and a clearance in the axial direction between a lower
surface of the impeller cover and at least one of the first raised
portion and the second raised portion is smaller than a clearance
in the axial direction between the lower surface of the impeller
cover and the upper shroud on the inner side in the radial
direction of the first raised portion.
2. The air blowing apparatus according to claim 1, wherein the
second raised portion is disposed on an outer edge in the radial
direction of the upper shroud.
3. The air blowing apparatus according to claim 1, wherein an upper
end of the first raised portion is disposed higher than an upper
end of the second raised portion.
4. The air blowing apparatus according to claim 1, wherein the
upper shroud includes a plurality of upper shroud wall portions
which are disposed in the circumferential direction and which
connect the first raised portion and the second raised portion
together.
5. The air blowing apparatus according to claim 4, wherein an inner
end in the radial direction of each of the upper shroud wall
portions is disposed in front of a corresponding outer end in the
radial direction of the upper shroud wall portion in a rotational
direction of the impeller.
6. The air blowing apparatus according to claim 4, wherein a height
in the axial direction of an upper end of each of the upper shroud
wall portions is equal to a height in the axial direction of the
upper end of the first raised portion.
7. The air blowing apparatus according to claim 4, wherein the
number of the upper shroud wall portions and the number of the
movable vanes are different from each other.
8. The air blowing apparatus according to claim 4, wherein at least
one of the upper shroud wall portions is disposed between the
adjacent movable vanes in the circumferential direction.
9. The air blowing apparatus according to claim 4, wherein the
upper shroud includes a plurality of upper side balance correcting
portions which are formed by the first raised portion, the second
raised portion, and the plurality of upper shroud wall portions,
and a shape of each of the upper side balance correcting portions
is asymmetric with respect to the central axis.
10. The air blowing apparatus according to claim 4, wherein the
upper shroud includes a plurality of upper side balance correcting
portions which are formed by the first raised portion, the second
raised portion, and the plurality of upper shroud wall portions,
and at least one of the upper side balance correcting portions is
provided with a weight.
11. The air blowing apparatus according to claim 8, wherein a lower
side balance correcting portion is formed on the outer side in the
radial direction of the motor.
12. The air blowing apparatus according to claim 11, wherein the
motor includes a rotor unit which includes a lidded cylindrical
rotor holder fixed to the shaft and opened upward, a stator unit
which faces the rotor unit in the radial direction, and a bearing
which rotatably supports the shaft relative to the stator unit, and
the rotor holder includes the lower side balance correcting
portion.
13. A vacuum cleaner comprising the air blowing apparatus according
to claim 1.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority to Japanese
Patent Application No. 2015-219104 filed on Nov. 9, 2015, and is a
Continuation Application of PCT Application No. PCT/JP2016/083017
filed on Nov. 8, 2016. The entire contents of each application are
hereby incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present disclosure relates to an air blowing apparatus
and a vacuum cleaner.
2. Description of the Related Art
[0003] A conventionally known air blowing apparatus includes an
impeller. For example, an air blowing apparatus is provided with an
unbalanced member having an asymmetric mass distribution.
[0004] In the air blowing apparatus, the unbalanced member having
an asymmetric mass distribution is attached in a phase opposite to
that of an unbalanced position of a rotor. However, in such an air
blowing apparatus, it is difficult to reduce the clearance between
a rotating fan and a fan cover and thereby to reduce the risk that
the air discharged by the rotating fan flows into the clearance
between the rotating fan and the fan cover.
SUMMARY OF THE INVENTION
[0005] An air blowing apparatus according to an exemplary
embodiment of the present disclosure includes: a motor which
includes a shaft disposed along a central axis extending
vertically; an impeller which is fixed to the shaft; and an
impeller cover which surrounds an upper side and an outer side in a
radial direction of the impeller and which includes a suction inlet
at a center. The impeller includes a plurality of movable vanes
which are disposed in a circumferential direction, a lower shroud
which is disposed on the lower side of the movable vanes, an upper
shroud which is disposed on the upper side of the movable vanes and
which includes a through hole penetrating in the axial direction.
The upper shroud includes a first raised portion which protrudes
upward from an upper surface of the upper shroud and which extends
in the circumferential direction and a second raised portion which
is disposed on the outer side in the radial direction of the first
raised portion, which protrudes upward from the upper surface of
the upper shroud, and which extends in the circumferential
direction. A clearance in the axial direction between a lower
surface of the impeller cover and at least one of the first raised
portion and the second raised portion is smaller than a clearance
in the axial direction between the lower surface of the impeller
cover and the upper shroud on the inner side in the radial
direction of the first raised portion.
[0006] The above and other elements, features, steps,
characteristics and advantages of the present disclosure will
become more apparent from the following detailed description of the
preferred embodiments with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a vertical cross-sectional view of an air blowing
apparatus of a first embodiment.
[0008] FIG. 2 is a bottom view illustrating a motor cover and the
like of the first embodiment.
[0009] FIG. 3 is a perspective view illustrating the motor cover
and the like of the first embodiment.
[0010] FIG. 4 is a top view of an annular member of the first
embodiment.
[0011] FIG. 5 is a top view of an impeller of the first
embodiment.
[0012] FIG. 6 is a perspective view of the impeller of the first
embodiment.
[0013] FIG. 7 is a bottom view of a rotor unit of a second
embodiment.
[0014] FIG. 8 is a vertical cross-sectional view of an air blowing
apparatus of a third embodiment.
[0015] FIG. 9 is a perspective view of an impeller of the third
embodiment.
[0016] FIG. 10 is a plan view of the impeller of the third
embodiment.
[0017] FIG. 11 is a perspective view of a vacuum cleaner.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] Hereinafter, a description is provided for an air blowing
apparatus according to embodiments of the present disclosure with
reference to the drawings. In the following description, a
direction in which a central axis J extends is defined as an axial
direction. In addition, the upper side in the axial direction is
simply referred to as the upper side, and the lower side in the
axial direction is simply referred to as the lower side. Note that
the axial direction, the upper and lower directions, the upper
side, and the lower side are simply names used for the purpose of
explanation and do not limit actual positional relationship or
directions. Additionally, a direction parallel to the central axis
J is simply referred to as the "axial direction," a radial
direction centered at the central axis J is simply referred to as
the "radial direction," and a circumferential direction centered at
the central axis J is simply referred to as the "circumferential
direction," unless otherwise noted. Note that in the following
description, hatching in cross-sections is omitted for
convenience.
[0019] Hereinafter, a description is provided for an air blowing
apparatus 1 according to an exemplary first embodiment of the
present disclosure. FIG. 1 is a vertical cross-sectional view of
the air blowing apparatus 1 of the first embodiment. The air
blowing apparatus 1 includes a motor 10 and an impeller 50.
[0020] The motor 10 includes a shaft 11 which is disposed along the
central axis J extending vertically. The motor 10 includes a rotor
unit 20, a stator unit 30, and bearings 40. Each of the bearings 40
supports the shaft 11 such that the shaft 11 can rotate relative to
the stator unit 30.
[0021] The rotor unit 20 includes a lidded cylindrical rotor holder
21 which is fixed to the shaft 11 and which is opened upward. In
the present embodiment, the rotor holder 21 is directly fixed to
the shaft 11. Note that the rotor holder 21 may be fixed to the
shaft 11 by the intermediary of another member.
[0022] The rotor holder 21 includes a rotor holder cylindrical
portion 22, a rotor holder bottom portion 23, and a lower side
balance correcting portion 24. The rotor holder cylindrical portion
22 is a tubular portion which extends in the axial direction. An
inner circumferential surface of the rotor holder cylindrical
portion 22 has a magnet 25 fixed thereto. The magnet 25 is
cylindrical.
[0023] The rotor holder bottom portion 23 is located on the lower
side of the rotor holder cylindrical portion 22. To be more
precise, the rotor holder bottom portion 23 is a substantially
plate-shaped portion which extends inwardly from the lower end of
the rotor holder cylindrical portion 22.
[0024] The rotor holder 21 includes the lower side balance
correcting portion 24. The lower side balance correcting portion 24
is included in at least one of the rotor holder cylindrical portion
22 and the rotor holder bottom portion 23. In the present
embodiment, the lower side balance correcting portion 24 is located
outside the rotor holder cylindrical portion 22. However, the lower
side balance correcting portion 24 may be included in a portion of
the rotor holder bottom portion 23.
[0025] The stator unit 30 faces the rotor unit 20 in the radial
direction. The stator unit 30 includes a stator core 31, and a coil
33 is formed by winding lead wire around the stator core 31 using
an insulator 32. In the present embodiment, the motor 10 is what is
called an outer rotor type. Thus, the stator core 31 is located on
the inner side of the magnet 25 fixed to the inner circumferential
surface of the rotor holder cylindrical portion 22 with a clearance
in the radial direction in between.
[0026] The stator unit 30 includes a bearing housing 34, an
attachment plate 35, and a circuit board 37. The bearing housing 34
is a tubular member which extends in the axial direction. The
bearing housing 34 has a tubular shape for holding the bearings 40
on the inner surface thereof. In the present embodiment, each of
the bearings 40 is a ball bearing. Note that the bearing 40 may be,
for example, a plain bearing.
[0027] The attachment plate 35 is located on the upper side of the
rotor holder 21 and the stator core 31. The attachment plate 35
spreads on the outer side of the bearing housing 34 and in a
direction perpendicular to the shaft 11. At least a portion of the
inner side of the attachment plate 35 is fixed to the bearing
housing 34. The attachment plate 35 is formed of a member made of
metal. The attachment plate 35 includes an attachment plate flange
portion 36 which protrudes from an outer edge in the radial
direction. In the present embodiment, three of the attachment plate
flange portions 36 are formed in the circumferential direction.
[0028] The motor 10 further includes a circuit board 37 which is
located on the lower side of the attachment plate 35 and on the
upper side of the rotor holder 21. The circuit board 37 spreads on
the outer side of the bearing housing 34 and in a direction
perpendicular to the shaft 11. In other words, the outer end of the
circuit board 37 is located on the outer side of the outer end of
the bearing housing 34. The inner end of the circuit board 37 is
fixed to the bearing housing 34. The circuit board 37 includes a
lead line 38 which is electrically connected to an external power
supply. In addition, a pullout line pulled out from the coil 33
formed in the stator core 31 is electrically connected to the
circuit board 37. The electrical connection between the circuit
board 37 and the pullout line is established by, for example,
solder joint.
[0029] The air blowing apparatus 1 includes an impeller 50 which is
located on the upper side of the motor 10. The impeller 50 is fixed
to the shaft 11. Thus, when the motor 10 fixed to the shaft 11
rotates, the impeller 50 fixed to the shaft 11 also rotates about
the central axis J together with the shaft 11. An impeller cover 60
surrounds the upper side and the outer side in the radial direction
of the impeller 50.
[0030] The impeller 50 includes multiple movable vanes 51, a lower
shroud 52, an upper shroud 53, and an upper side balance correcting
portion 54. The upper side balance correcting portion 54 is
included in the upper shroud 53. To be more precise, the upper side
balance correcting portion 54 is located in a region on the outer
side of the upper surface of the upper shroud 53.
[0031] The multiple movable vanes 51 are disposed in the
circumferential direction. In other words, the impeller 50 includes
multiple movable vanes 51 disposed in the circumferential
direction. In the present embodiment, all of the multiple movable
vanes 51 have the same shape. To be more specific, the movable
vanes 51 are of a single type. However, the multiple movable vanes
51 may have different shapes. For example, some of the movable
vanes may have a length long in the radial direction, while the
other movable vanes may have a length short in the radial
direction.
[0032] The lower shroud 52 is located on the lower side of the
movable vanes 51. In other words, the impeller 50 includes a lower
shroud 52 disposed on the lower side of the movable vanes 51. The
lower portions of the multiple movable vanes 51 are connected to
the lower shroud 52. The inner side of the lower shroud 52 has a
through hole 521 vertically penetrating therethrough, and the shaft
11 is press-fitted to the through hole 521 and then is fixed. Note
that the shaft 11 may be fixed to the lower shroud 52 by a method
other than press fitting. In the present embodiment, the upper
surface of the lower shroud 52 is located highest at the central
portion and smoothly descends toward the outside. This improves air
blow efficiency of the impeller 50 because air flowing from the
upper side is guided toward the outer side in the radial direction
along the upper surface of the lower shroud 52. Note that the lower
shroud 52 has a different shape, for example a flat-plate shape
spreading in a direction perpendicular to the shaft 11.
[0033] The inner side of the lower surface of the lower shroud 52
is located on the upper side of any other portion of the lower
surface of the lower shroud 52. The lower surface of the lower
shroud 52 has a shape smoothly descending from the inner side
toward the outer side. The lower shroud 52 includes multiple lower
shroud ribs 522 which are disposed on the lower surface in the
circumferential direction. The position in the axial direction of
the lower end of the lower shroud ribs 522 is substantially the
same as the position in the axial direction of the outer edge of
the lower shroud 52. Note that the lower end of the lower shroud 52
may be located on the upper side of the outer edge of the lower
shroud 52. The lower shroud ribs 522 are located on the back side
in the rotational direction R of the impeller from the inner side
toward the outer side. This makes it possible to discharge air
located between the lower shroud 52 and the upper surface of a
diffuser 70 to be described later to the outside because when the
impeller 50 rotates, the lower shroud ribs 522 also rotate
together. In addition, if the lower shroud ribs 522 are formed, the
rigidity of the impeller 50 improves.
[0034] The upper shroud 53 is located on the upper side of the
movable vanes 51. The upper shroud 53 has a through hole 531
penetrating in the axial direction. To be more precise, the
impeller 50 includes an upper shroud 53 which is disposed on the
upper side of the movable vanes 51 and which has a through hole 531
penetrating in the axial direction. The upper portions of the
multiple movable vanes 51 are connected to the upper shroud 53. The
through hole 531 penetrating in the axial direction is formed in
the central portion of the upper shroud 53. Thus, air suctioned
from the upper side of the impeller 50 is suctioned via the through
hole 531 of the upper shroud 53 into the impeller 50. The upper
shroud 53 has a shape smoothly descending from the inner end toward
the outer side. Therefore, air suctioned into the impeller 50 is
guided to smoothly descend toward the outer side along the lower
surface of the upper shroud 53 and the upper surface of the lower
shroud 52.
[0035] The impeller cover 60 surrounds the upper side and the outer
side in the radial direction of the impeller 50. In addition, the
impeller cover 60 includes a suction inlet 61 at the center. This
makes it possible to suction air on the upper side of the air
blowing apparatus 1 via the suction inlet 61 into the air blowing
apparatus 1. The air suctioned via the suction inlet 61 passes via
the through hole 531 formed in the upper shroud 53 and is taken
into the impeller 50.
[0036] The impeller cover 60 includes an impeller cover upper edge
portion 62 which forms the suction inlet 61, an impeller cover
slope 63 which spreads and smoothly descends from the outer side of
the impeller cover upper edge portion 62 toward the outside, an
impeller cover raised portion 64 which protrudes upward from the
outer side of the impeller cover slope 63, and an impeller cover
tubular portion 65 which extends downward from the outer side of
the impeller cover raised portion 64.
[0037] The lower surface of the impeller cover slope 63 faces the
upper surface of the upper shroud 53 with a clearance in between.
The clearance formed between the lower surface of the impeller
cover slope 63 and the upper surface of the upper shroud 53 is
substantially uniform. This makes it possible to suppress the
reduction in air blow efficiency of the air blowing apparatus 1
attributed to inflow of air between the impeller cover slope 63 and
the upper shroud 53.
[0038] The impeller cover raised portion 64 is a portion which
protrudes upward from the outer side of the impeller cover slope
63. The impeller cover raised portion 64 is formed annularly
centered at the central axis J. The lower surface of the impeller
cover raised portion 64 is located higher than the outer side of
the lower surface of the impeller cover slope 63. To be more
specific, within a region where the impeller cover raised portion
64 is located, the lower surface of the impeller cover 60 is
recessed upward. The space formed on the lower side of the impeller
cover raised portion 64 contains the upper side balance correcting
portion 54 located therein.
[0039] The inner surface of the impeller cover tubular portion 65
spreads from the outer side of the outer end of the impeller 50 and
descends toward the outside, forming a smooth surface. Thus, the
air discharged from the impeller 50 is guided to smoothly descend
toward the outside. In the present embodiment, the inner surface of
the impeller cover tubular portion 65 includes an impeller cover
guide portion 66 which is raised inward and downward and is located
on the lower side of the lower end of the upper shroud 53. The
impeller cover guide portion 66 and a diffuser flat plate portion
71 to be described later face each other with a clearance in
between. The clearance described above has a portion narrowest at a
position in the axial direction which is almost the same as that of
or is on the lower side of the upper surface of the lower shroud
52. This makes it possible to temporarily raise the static pressure
of the air discharged from the impeller 50 and to improve the air
blow efficiency of the air blowing apparatus 1.
[0040] The air blowing apparatus 1 further includes a diffuser 70
at least a portion of which is located on the upper side of the
stator unit 30. The diffuser 70 includes a diffuser flat plate
portion 71 and upper side static vanes 72. The diffuser flat plate
portion 71 spreads in a direction perpendicular to the shaft 11.
The diffuser flat plate portion 71 is located on the upper side of
the stator unit 30 and is located on the lower side of the lower
shroud 52. The upper surface of the diffuser flat plate portion 71
faces the lower surface of the lower shroud 52 in the axial
direction with a clearance in between.
[0041] The diffuser 70 is fixed to the stator unit 30 on the lower
side of the impeller cover 60. To be more specific, the attachment
plate 35 is fixed to the diffuser 70. To sum up, the lower surface
of the diffuser flat plate portion 71 is foxed to the attachment
plate flange portion 36. This makes it possible to precisely fasten
the diffuser 70 and the stator unit 30 together. Since the
attachment plate 35 is a flat plate shaped metal member spreading
in a direction perpendicular to the shaft 11, when the upper
surface of the attachment plate flange portion 36 and the lower
surface of the diffuser flat plate portion 71 come into surface
contact with each other, it is possible to precisely fix the
attachment plate 35 and the diffuser flat plate portion 71 together
in a direction perpendicular to the shaft 11. Note that the
attachment plate 35 or the diffuser 70 may be a member formed of a
different material.
[0042] The diffuser 70 has a diffuser through hole 73 penetrating
in the axial direction. To be more specific, a substantially
circular diffuser through hole 73 centered at the central axis J is
formed in the center of the diffuser flat plate portion 71. At
least a portion of the bearing housing 34 is fitted into the
diffuser through hole 73. This makes it possible to improve
coaxiality of the bearing housing 34 and the diffuser 70. In the
present embodiment, a fitting portion 341 fitted to the diffuser
through hole 73 is formed on the outer side above the bearing
housing 34. In the present embodiment, the fitting portion 341 is
partially fitted and thus can be fixed to the edge of the diffuser
through hole 73 while improving the coaxiality of the bearing
housing 34 and the diffuser 70. Note that the diffuser 70 and the
stator unit 30 may be fixed by a different structure. For example,
a portion of the bearing housing 34 and a portion of the diffuser
70 may be strongly fixed together, and the attachment plate 35 and
the diffuser 70 may be distant from each other.
[0043] The diffuser 70 includes a tubular shaped diffuser tubular
portion 74 which extends downward from the outer side of the
diffuser flat plate portion 71. The multiple upper side static
vanes 72 disposed in the circumferential direction are located on
the outer surface of the diffuser tubular portion 74. In other
words, the diffuser 70 includes the multiple upper side static
vanes 72. The multiple upper side static vanes 72 are disposed in
the circumferential direction and on the outer side of the diffuser
flat plate portion 71. The outer side of the upper side static
vanes 72 is connected to a middle cover 75 extending in the shape
of a tube.
[0044] The upper portion of the middle cover 75 is connected to the
lower portion of the impeller cover tubular portion 65. The upper
side static vanes 72 are located on the outer side of and the lower
side of the outer end of the impeller 50. Thus, the air guided in
the impeller cover 60 passes through a flow path formed by the
outer surface of the diffuser tubular portion 74 and the inner
surface of the middle cover 75 and is discharged downward. At that
moment, the upper side static vanes 72 disposed in the flow path
can guide the air flowing in the flow path smoothly toward the
lower side. Thus, it is possible to improve the air blow efficiency
of the air blowing apparatus 1. In the present embodiment, the
diffuser flat plate portion 71, the upper side static vanes 72, and
the middle cover 75 form a single member made of resin. Note that
the diffuser flat plate portion 71, the upper side static vanes 72,
and the middle cover 75 may be separate members. In addition, the
middle cover 75 and the impeller cover 60 may form a single unit.
To be more specific, the impeller cover tubular portion 65 may
extend downward over a length longer than FIG. 1 such that the
lower end of the impeller cover tubular portion 65 is located below
the region where the upper side static vanes 72 are located.
[0045] FIG. 2 is a bottom view illustrating a motor cover 80 and
the like. As illustrated in FIGS. 1 and 2, the air blowing
apparatus 1 includes the motor cover 80. The motor cover 80 is
located on the lower side of the impeller cover 60 and is located
on the outer side in the radial direction of the motor 10. In
addition, the motor cover 80 has a tubular shape extending in the
axial direction and opened downward.
[0046] In the present embodiment, lower side static vanes 81 and a
blower case 82 are disposed on the outer side of the motor cover
80. The lower side static vanes 81 are static vanes disposed on the
outer surface of the motor cover 80 at equal intervals in the
circumferential direction. The outer side of the lower side static
vanes 81 is connected to the blower case 82. The blower case 82 has
a tubular shape extending in the axial direction. The upper portion
of the blower case 82 is connected to the lower portion of the
middle cover 75. The motor cover 80 and the blower case 82 face
each other in the radial direction with a clearance in between and
form a flow path which allows air discharged through the upper side
static vanes 72 to flow. Note that in the present embodiment, the
motor cover 80, the lower side static vanes 81, and the blower case
82 form a single member made of resin. However, the motor cover 80,
the lower side static vanes 81, and the blower case 82 may be
separate members.
[0047] The blower case 82 includes a blower case outer tubular
portion 83, a blower case connection portion 84, and a blower case
inner tubular portion 85. The blower case outer tubular portion 83
is a tubular portion which is connected to the lower portion of the
middle cover 75 and which extends downward in the axial direction
from the lower portion of the middle cover 75. The lower portion of
the blower case outer tubular portion 83 is smoothly curved toward
the inner side and is connected to the blower case connection
portion 84. The blower case connection portion 84 is a portion
which is smoothly curved downward toward the inner side. The inner
side of the blower case connection portion 84 is connected to the
blower case inner tubular portion 85. The blower case inner tubular
portion 85 is a tubular portion which is connected to the lower
portion of the blower case connection portion 84 and which extends
downward.
[0048] Since the blower case 82 has the above structure, the air
discharged downward from the upper side static vanes 72 flows
downward along the flow path formed on the inner side of the blower
case outer tubular portion 83, flows inward along the inner side of
the blower case connection portion 84, and flows downward along the
inner side of the blower case inner tubular portion 85. Here, if
the air blowing apparatus 1 of the present embodiment is mounted on
a vacuum cleaner, for example, the air suctioned through the
suction inlet 61 may contain trash or water. In that case, it is
necessary that the trash or water do not come into contact with the
motor 10. Since the motor cover 80 is disposed on the outer side of
the motor 10 in the air blowing apparatus 1, trash or water
contained in the suctioned air does not intrude into the motor
cover 80. This makes it possible for trash or water not to come
into contact with the motor 10.
[0049] FIG. 3 is a perspective view illustrating the motor cover 80
and the like. The motor cover 80 includes at least one lead line
holder 87 in the circumferential direction. Thus, the motor cover
80 includes a tubular shaped motor cover tubular portion 86 and the
lead line holder 87. The lead line 38 is held by the lead line
holder 87. In the present embodiment, the lead line holder 87 is a
through hole which is formed in a portion of the motor cover 80 and
which penetrates in the axial direction. The outer end of the lead
line holder 87 is located on the outer side of the outer end of the
motor cover tubular portion 86, and the inner end of the lead line
holder 87 is located on the inner side of the inner end of the
motor cover tubular portion 86. To be more specific, in the motor
cover 80, the lead line holder 87 is a through hole penetrating in
the axial direction and has a shape more bulging in the radial
direction than the motor cover tubular portion 86 does. This makes
it possible to hold the lead line 38. If there is not lead line
holder 87 and the lead line 38 extends downward from the circuit
board 37, the lead line 38 vibrates due to the air flowing in the
air blowing apparatus 1. On the other hand, in the present
embodiment, the lead line holder 87 provided makes it possible to
suppress large vibration of the lead line 38.
[0050] Since the outer end of the lead line holder 87 more bulges
outward than the motor cover tubular portion 86 does, the width in
the radial direction of the flow path formed by the motor cover 80
and the blower case 82 is narrower on the outer side of the lead
line holder 87 than the outer side of the motor cover tubular
portion 86. In addition, the lower side static vanes 81 are not
disposed on the outer side of the lead line holder 87. It is
desirable that the flow path have an axially symmetric shape in the
flow of air in the flow path. In that case, the area of the
cross-section of the flow path is axially symmetric centered at the
central axis J and thus the pressure distribution of the air or the
resistance applied to the air is nearly axially symmetric. As a
result, the air blow efficiency improves. On the other hand, since
the lead line holder 87 is provided in the present embodiment, the
flow path is narrow on the outer side of the lead line holder 87
when viewed in the axial direction. Hence, if the lower side static
vanes 81 are not disposed on the outer side of the lead line holder
87, it is possible to increase the area of the cross-section of the
flow path compared to the case of providing the lower side static
vanes 81. Therefore, when the air is flowing in the flow path, it
is possible to establish nearly the same conditions of pressure or
resistance force applied to the air on the outer side of the motor
cover tubular portion 86 and on the outer side of the lead line
holder 87. Consequently, the air blow efficiency of the air blowing
apparatus 1 improves. Note that since the lead line holder 87 may
have a different shape or configuration, the area of the
cross-section of the flow path and the pressure distribution may be
adjusted by appropriately choosing a structure different from the
above structure when fabricating the lead line holder 87 having a
structure other than that of the present embodiment.
[0051] Note that the lead line holder 87 may have a different
shape. For example, the inner surface of the motor cover 80 may
have a hook and a portion of the lead line 38 may be fixed to the
hook. In addition, the lead line holder 87 may be provided on the
lower surface of the diffuser 70 and may extend outward along the
diffuser 70, may be fixed to a portion of the upper side static
vanes 72, and may be pulled out to the outside of the air blowing
apparatus 1. The upper end of the lead line holder 87 is located on
the lower side of the upper end of the motor cover tubular portion
86. To be more precise, the upper surface of the motor cover
tubular portion 86 has a motor cover cutout portion 88 which is
recessed downward, and the upper end of the lead line holder 87
corresponds to the motor cover cutout portion 88.
[0052] The upper surface of the motor cover tubular portion 86
includes the motor cover cutout portion 88 which is recessed
downward. A plurality of the motor cover cutout portions 88 are
disposed in the circumferential direction. The attachment plate
flange portion 36 is disposed on the upper side of the motor cover
cutout portions 88. In the present embodiment, the attachment plate
flange portion 36 and each of the motor cover cutout portions 88
face each other with a clearance in the axial direction in between.
In short, each of the motor cover cutout portions 88 forms a
communication path 881 which establishes communication between the
inside and the outside of the motor cover 80.
[0053] In the air blowing apparatus 1, the impeller cover 60, the
middle cover 75, and the blower case 82 form the outer surface of
the air flow path as in FIG. 1. However, the outer surface of the
flow path need not be formed by three members and may be formed
only by the impeller cover 60, for example. To be more specific,
the length in the axial direction of the impeller cover 60 may be
longer than that illustrated in FIG. 1, and the impeller cover
tubular portion 65 may have substantially the same diameter and
have a shape extending downward. In the air blowing apparatus
having this configuration, the air discharged from the impeller is
smoothly guided downward. Thus, the air blow efficiency
improves.
[0054] On the other hand, in the air blowing apparatus 1, the air
flowing in the flow path is guided inward by the blower case
connection portion 84. By this configuration, the flow path can be
closer to the motor cover 80. A portion of the air flowing downward
in the flow path flows through the lower portion of the motor cover
80 into the motor cover 80, and then flows upward inside the motor
cover 80. Hence, it is possible to cool the motor 10. The air cools
the motor 10, and then flows through the communication path 881, is
discharged to the outside of the motor cover 80, and again flows
downward outside the motor cover 80.
[0055] Note that in the air blowing apparatus 1 of the first
embodiment, the movable vanes 51, the upper side static vanes 72,
and the lower side static vanes 81 are all different in number from
one another. Generally, in the air blowing apparatus, noise and
vibration occurs in the air blowing apparatus while the impeller is
rotating. Noise and vibration can be amplified particularly in the
case where the number of movable vanes and the number of static
vanes are the same or where the number of one type is a multiple of
the number of another type. On the other hand, in the air blowing
apparatus 1, the number of movable vanes 51, the number of upper
side static vanes 72, and the number of lower side static vanes 81
are mutually prime. Hence, noise and vibration are not amplified as
described above. Moreover, in the air blowing apparatus 1, the
number of movable vanes 51, the number of upper side static vanes
72, and the number of lower side static vanes 81 are all different
prime numbers. Therefore, noise and vibration are further
reduced.
[0056] The lower side balance correcting portion 24 is formed on
the outer side in the radial direction of the motor 10. In the
present embodiment, the lower side balance correcting portion 24 is
formed by an annular member 26 fixed to the outer surface of the
rotor holder cylindrical portion 22. If the lower side balance
correcting portion 24 is formed on the outer side in the radial
direction of the motor 10, the work of balance correction becomes
easy. FIG. 4 is a top view of the annular member 26. As illustrated
in FIGS. 1 and 4, the annular member 26 includes an annular member
bottom portion 261, an annular member tubular portion 262, and
multiple annular member wall portions 263. The annular member 26 is
a resin member separate from the rotor holder 21. The annular
member 26 if fixed to the lower side of the outer circumferential
surface of the rotor holder cylindrical portion 22.
[0057] The annular member bottom portion 261 is an annular portion
centered at the central axis J. The inner end of the annular member
bottom portion 261 is fixed to the outer circumferential surface of
the rotor holder cylindrical portion 22. The annular member tubular
portion 262 has a tubular shape extending upward from the outer
edge of the annular member bottom portion 261. Each of the annular
member wall portions 263 is a portion extending inward from the
inner surface of the annular member tubular portion 262. The inner
end of the annular member wall portion 263 comes into contact with
the outer surface of the rotor holder cylindrical portion 22. In
this configuration, the rotor holder cylindrical portion 22 and the
annular member 26 form multiple spaces which are opened upward and
partitioned in the circumferential direction. In the case of
correcting the balance of the assembly of the motor 10 and the
impeller 50, it is possible to correct the mass distribution of the
assembly relative to the central axis J by providing a weight 264
in at least one of the multiple spaces described above. Thus, the
rotational balance of the assembly is corrected. Note that compared
to the case of providing the lower side balance correcting portion
24 on the inner surface of the rotor holder cylindrical portion 22,
the workability of balance correction improves in the present
embodiment because the lower side balance correcting portion 24 can
be provided on the outer side of the rotor holder cylindrical
portion 22. Note that in the present embodiment, lower side balance
correcting portion 24 is formed by the annular member 26 but may be
formed by a different member or method.
[0058] FIG. 5 is a top view of the impeller 50, and FIG. 6 is a
perspective view of the impeller 50. As illustrated in FIGS. 1, 5,
and 6, the impeller 50 includes an upper side balance correcting
portion 54. In the present embodiment, the upper side balance
correcting portion 54 is formed in the upper surface of the upper
shroud 53. The upper shroud 53 includes a first raised portion 541,
a second raised portion 542, and upper shroud wall portions 543.
The first raised portion 541 is an annular portion protruding
upward from the upper surface of the upper shroud. The second
raised portion 542 is an annular portion protruding upward from the
upper surface of the upper shroud. The second raised portion 542 is
located on the outer side of the first raised portion 541. In other
words, the upper shroud 53 includes: the first raised portion 541
which protrudes upward from the upper surface of the upper shroud
53 and which extends in the circumferential direction; and the
second raised portion 542 which is located on the outer side in the
radial direction of the first raised portion 541, which protrudes
upward from the upper surface of the upper shroud 53, and which
extends in the circumferential direction. The clearance in the
axial direction between the lower surface of the impeller cover 60
and at least one of the first raised portion 541 and the second
raised portion 542 is smaller than the clearance in the axial
direction between the lower surface of the impeller cover 60 and
the upper shroud 53 on the inner side in the radial direction of
the first raised portion 541. This makes it possible to suppress
inflow of the air, discharged by the impeller 50 to the outside in
the radial direction, into the space between the upper shroud 53
and the lower surface of the impeller cover 60. Thus, the air blow
efficiency of the air blowing apparatus 1 improves. In the present
embodiment, second raised portion 542 is disposed on the outer edge
of the upper shroud. This makes it possible to further suppress
inflow of the air, discharged by the impeller 50 to the outside in
the radial direction, into the space between the upper shroud 53
and the lower surface of the impeller cover 60. The multiple upper
shroud wall portions 543 are disposed in the circumferential
direction and connect the first raised portion 541 and the second
raised portion 542 together. To be more precise, the upper shroud
53 includes multiple upper shroud wall portions 543 which are
disposed in the circumferential direction and which connect the
first raised portion 541 and the second raised portion 542
together. In this way, it is possible to improve the rigidity of
the upper shroud 53.
[0059] The above configuration forms multiple spaces in the
circumferential direction in the upper surface of the upper shroud
53 which are open upward and which are partitioned by the first
raised portion 541, the second raised portion 542, and the upper
shroud wall portions 543. In other words, the upper shroud 53
includes multiple upper side balance correcting portions 54 which
are formed by the first raised portion 541, the second raised
portion 542, and the multiple upper shroud wall portions 543. At
least one of the upper side balance correcting portions 54 is
provided with a weight 544. To sum up, in the case of correcting
the balance of the assembly of the motor 10 and the impeller 50, it
is possible to correct the mass distribution of the assembly
relative to the central axis J by providing a weight 544 in at
least one of the multiple spaces described above. Thus, the
rotational balance of the assembly is corrected. Note that in the
present embodiment, it is possible to easily correct the balance
even after the assembly is built because the upper side balance
correcting portions 54 are formed in the upper surface of the upper
shroud 53. In short, the workability of correcting the balance of
the assembly improves.
[0060] The upper end of the first raised portion 541 is disposed
higher than the upper end of the second raised portion 542. In
other words, the first raised portion 541 protrudes higher than the
second raised portion 542. If the second raised portion 542 is
provided, it is possible to reduce the risk that a portion of the
air discharged to the outside of the impeller 50 could flow onto
the upper surface of the upper shroud 53. In addition, since first
raised portion 541 protrudes higher than the second raised portion
542, it is possible to reduce the risk that the air inside the
spaces formed by the first raised portion 541, the second raised
portion 542, and the upper shroud wall portion 543 could flow
inward beyond the first raised portion 541. Moreover, the air tends
to flow outward beyond the first raised portion 541 rather than to
flow inward beyond the second raised portion 542. In other words,
since the upper end of the first raised portion 541 is located
higher than the upper end of the second raised portion 542, the
labyrinth characteristic between the impeller cover 60 and the
upper surface of the upper shroud 53 improves.
[0061] The inner end of each of the upper shroud wall portions 543
is located in front of the corresponding outer end of the upper
shroud wall portion 543 in the rotational direction R of the
impeller. In other words, the inner end in the radial direction of
each upper shroud wall portion 543 is disposed in front of the
outer end in the radial direction of that upper shroud wall portion
543 in the rotational direction R of the impeller. As illustrated
in FIGS. 5 and 6, from the inner side toward the outer side, each
upper shroud wall portion 543 is smoothly curved toward rear in the
rotational direction R of the impeller. To be more precise, each
upper shroud wall portion 543 has a shape similar to that of each
movable vane 51. When the impeller 50 rotates, the upper shroud
wall portions 543 also rotate together with the impeller 50, and
each of the upper shroud wall portions 543 serves as a movable
vane. In this way, it is possible to discharge the air located in
the spaces formed between the impeller cover 60 and the upper
surface of the upper shroud 53 to the outside. In addition, it is
possible to reduce the risk that the air discharged by the impeller
50 to the outside could flow onto the upper surface of the upper
shroud 53. To put it differently, when the upper shroud wall
portions 543 rotate together with the impeller 50, the upper shroud
wall portions 543 are given a labyrinth function. Moreover, since
the upper end of the first raised portion 541 is located higher
than the upper end of the second raised portion 542, the air
located between the first raised portion 541 and the second raised
portion 542 is more easily discharged to the outside. Here in the
present embodiment, from the inner side toward the outer side, each
upper shroud wall portion 543 is smoothly curved toward rear in the
rotational direction R of the impeller. However, the upper shroud
wall portion 543 may have a different shape. For example, from the
inner side toward the outer side, the upper shroud wall portion 543
may be a flat plate shaped portion located rear in the rotational
direction R of the impeller. In addition, the height in the axial
direction of the upper end of the upper shroud wall portion 543 is
equal to the height in the axial direction of the upper end of the
first raised portion 541. Thus, if the upper shroud wall portion
543 is higher, it is possible to more efficiently discharge the air
in the spaces formed between the impeller cover 60 and the upper
surface of the upper shroud 53 to the outside.
[0062] The number of upper shroud wall portions 543 and the number
of movable vanes 51 are different from each other. Thus, the number
of hissing noises produced from the movable vanes 51 differs from
the number of hissing noises produced from the upper shroud wall
portions 543 over the period of one rotation of the impeller 50
about the central axis J. As a consequence, it is possible to
reduce the risk that the hissing noise of the movable vanes 51 and
the hissing noise of the upper shroud wall portion 543 occur at the
same time to produce a loud noise.
[0063] At least one of the upper shroud wall portions 543 is
disposed between adjacent movable vanes 51 in the circumferential
direction. To put it differently, at least one of the outer ends in
the radial direction of the upper shroud wall portions 543 is
disposed in the circumferential direction between the outer end in
the radial direction of a movable vane 51 and the outer end in the
radial direction of a movable vane 51 adjacent to that movable vane
51. Thus, the upper shroud wall portions 543 and the movable vanes
51 are disposed at different positions in the circumferential
direction. Hence, the balance of the upper shroud 53 is enhanced
and the rigidity as a whole improves in a well balanced manner. In
addition, when the impeller 50 rotates, hissing noise by the upper
shroud wall portions 543 and hissing noise by the movable vanes 51
are prevented from occurring at a particular location in the
circumferential direction. Therefore, it is possible to reduce the
noise by the impeller 50.
[0064] Note that in the present embodiment, the impeller 50
includes the upper side balance correcting portion 54, and the
rotor holder 21 includes the lower side balance correcting portion
24. This makes it possible to correct the balance at two locations
of the assembly of the impeller 50 and the motor 10 after the
assembly is built. Here, in the present embodiment, the lower side
balance correcting portion 24 is formed on the lower side of the
rotor holder 21, and the upper side balance correcting portion 54
is formed on the upper surface of the upper shroud 53. For this
reason, it is easy to correct the balance of the assembly even
after the diffuser 70 is fixed to the motor 10. Moreover, in the
present embodiment, the motor cover 80 is opened downward. In other
words, the motor cover 80 is tubular and does not have a structure
to close the lower side thereof. This makes it possible to correct
the balance using the lower side balance correcting portion 24 even
after the motor cover 80 is built in.
[0065] In the present embodiment, the upper side balance correcting
portion 54 is formed by the first raised portion 541, the second
raised portion 542, and the upper shroud wall portions 543 formed
on the upper surface of the upper shroud 53, and the weight 544
disposed on the upper surface of the upper shroud 53 corrects the
balance. However, the upper side balance correcting portion 54 may
have a different configuration. For example, a so-called minus
balance mechanism may be employed in which a portion of the outer
edge of the upper shroud 53 is cut out to adjust the weight of the
impeller 50 and thus the balance of the assembly of the impeller 50
and the motor 10 is corrected. In that case, the shape of the upper
side balance correcting portion 54 is asymmetric with respect to
the central axis J. This makes it possible to correct the balance
of the impeller 50.
[0066] Next, a description is provided for an air blowing apparatus
1A according to an exemplary second embodiment of the application
of the present disclosure. In the description of the air blowing
apparatus 1A according to the second embodiment, the same
explanation as that of the air blowing apparatus 1 of the first
embodiment is omitted. In addition, the parts and the members
having the same configurations as those of the first embodiment are
given the same reference signs as those of the first
embodiment.
[0067] FIG. 7 is a bottom view of a rotor unit 20A of the air
blowing apparatus 1A according to the second embodiment. The
configuration of the air blowing apparatus 1A according to the
second embodiment is listed below with reference to FIGS. 1 and 7.
Note that description is provided only for the details of the
members and the parts different from those of the first embodiment,
not for the members and the parts same as those of the first
embodiment. To be more specific, the air blowing apparatus 1A
includes: a motor 10A which has a shaft 11 disposed along the
central axis J extending vertically; an impeller 50 which is fixed
to the shaft 11; an impeller cover 60 which surrounds the upper
side and the outer side in the radial direction of the impeller 50
and which has a suction inlet 61 at the center; a motor cover 80
which is located on the lower side of the impeller cover 60 and
which is located on the outer side in the radial direction of the
motor 10A; and a blower case 82 which is located on the lower side
of the impeller cover 60 and which is located on the outer side in
the radial direction of the motor cover 80. The motor 10A includes:
a rotor unit 20A which includes a lidded cylindrical rotor holder
21A fixed to the shaft 11 and opened upward; a stator unit 30 which
faces the rotor unit 20A in the radial direction; and bearings 40
each of which supports the shaft 11 such that the shaft 11 can
rotate relative to the stator unit 30. The motor cover 80 has a
tubular shape extending in the axial direction and opened downward.
The blower case 82 has a tubular shape extending in the axial
direction and opened downward. The impeller 50 includes multiple
movable vanes 51 disposed in the circumferential direction. The
rotor holder 21 includes a rotor holder cylindrical portion 22 and
a rotor holder bottom portion 23A which is located on the lower
side of the rotor holder cylindrical portion 22. The lower end of
the motor cover 80 is located on the upper side in the axial
direction of the lower end of the blower case 82, and the motor
cover 80 includes a communication path 881 which establishes
communication in the radial direction between the inside and the
outside of the motor cover 80, the communication path being located
on the upper side of the lower end of the motor cover 80.
[0068] In the above configuration, the impeller cover 60, the motor
cover 80, and the blower case 82 form a flow path which guides
downward the air discharged from the impeller 50 to the outside in
the air blowing apparatus 1A. Here, in the air blowing apparatus
disclosed in Japanese Unexamined Patent Application Publication No.
2003-129995, no motor cover is disposed on the outer side of the
motor. For this reason, it is difficult to cool the motor such that
trash or water contained in the gas discharged from the impeller
will not come into contact with the motor. If the motor cover is
disposed on the outer side of the motor, however, the air
discharged from the impeller does not come into contact with the
motor, which makes it difficult to cool the motor. Thus, it is
necessary to fabricate an air blowing apparatus which prevents
trash or water contained in the air discharged from the impeller
from coming into contact with the motor and at the same time which
cools the motor.
[0069] In the air blowing apparatus 1A, the lower end of the motor
cover 80 is located on the upper side in the axial direction of the
lower end of the blower case 82. Thus, most of the air flowing
through the flow path formed by the impeller cover 60, the motor
cover 80, and the blower case 82 is discharged toward the lower
side of the motor cover 80. However, a portion of the air which has
flowed through the flow path is discharged to the lower side of the
motor cover 80 and then enters the motor cover 80, and after that
flows inside the motor cover 80 toward the upper side in the axial
direction. This makes it possible to cool the motor 10A. A portion
of the air which has cooled the motor 10A passes through the
communication path 881 which establishes communication in the
radial direction between the inside and the outside of the motor
cover 80 and is discharged to the outside of the motor cover 80.
Here, if the air blowing apparatus 1A is mounted on a vacuum
cleaner, for example, there is a case where it is desirable to
raise the temperature of the air discharged from the air blowing
apparatus 1A as high as possible. If the air blowing apparatus 1A
is mounted, a portion of the air discharged from the impeller 50
can cool the motor 10A as described above, and it is possible to
raise the temperature of the air by thermal conduction. Thus,
compared to the air discharged from the impeller 50, the
temperature is high for the air passing through the communication
path 881 and again flowing downward through the flow path located
on the outer side of the motor cover 80. Therefore, it is possible
to discharge air having a higher temperature from the air blowing
apparatus 1A.
[0070] In addition, the air blowing apparatus 1A further includes,
on the lower side of the impeller cover 60, a diffuser 70 which is
fixed to the stator unit 30 and at least a portion of which is
located on the upper side of the stator unit 30. Moreover, the
stator unit 30 includes: a tubular bearing housing 34 which holds
the bearings 40 on the inner surface thereof and which holds a
stator core 31 on the outer surface thereof; and an attachment
plate 35 which is fastened to the bearing housing 34 and which
spreads in a direction perpendicular to the shaft 11 on the outer
side of the bearing housing 34. The attachment plate 35 is fixed to
the diffuser 70.
[0071] Since the air blowing apparatus 1A has the configuration
described above, the cooling characteristic of the motor 10A
further improves. The attachment plate 35 of the second embodiment
is a member made of metal. In addition, the attachment plate 35 is
connected to a member the temperature of which tends to rise, such
as the stator core 31 and the bearings 40. Thus, when the
temperature of the motor 10A becomes high, heat is easily conducted
to the attachment plate 35 from a member such as the stator core 31
which tends to become a heat source. Then, the heat stored in the
attachment plate 35 is cooled by the air flowing inside the motor
cover 80. As a result, the cooling characteristic of the motor 10A
improves.
[0072] In addition, in the second embodiment, the diffuser 70
includes: a diffuser flat plate portion 71 which spreads in the
radial direction; and a diffuser tubular portion 74 which extends
downward in the axial direction from the outer end of the diffuser
flat plate portion 71. The communication path 881 is located on the
upper side in the axial direction of the lower end of the diffuser
tubular portion 74. Thus, the space formed in the radial direction
between the diffuser tubular portion 74 and the motor cover 80 has
a negative pressure compared to the inside of the flow path. For
this reason, it becomes easier for the air which has cooled the
motor 10A to flow through the communication path 881. Therefore, it
is possible to effectively cool the motor 10A.
[0073] The attachment plate 35 is located on the upper side in the
axial direction of the lower end of the diffuser tubular portion
74. Thus, the attachment plate 35 is disposed near the region where
the communication path 881 is formed. As a result, the air flowing
upward inside the motor cover 80 comes into contact with the
attachment plate 35 to cool the attachment plate 35, passes through
the communication path 881, and then is discharged to the outside
of the motor cover 80. Thus, the cooling characteristic of the
motor 10A further improves.
[0074] Furthermore, a portion of the attachment plate 35 forms a
portion of the communication path 881. To be more specific, with
reference to FIGS. 1 and 7, the attachment plate 35 includes an
attachment plate flange portion 36, and the attachment plate flange
portion 36 protrudes outward from the motor case through the motor
cover cutout portion 88. Thus, a portion of the motor cover cutout
portion 88 and a portion of the attachment plate flange portion 36
form the communication path 881 which establishes communication
through the motor cover 80 in the radial direction. As a result,
the air flowing upward inside the motor cover 80 passes through the
communication path 881 along a portion of the attachment plate 35
and is discharged to the outside of the motor cover 80. This
configuration makes it possible to efficiently cool the attachment
plate 35 and more effectively deprive the attachment plate 35 and
the stator unit 30 of heat.
[0075] As illustrated in FIG. 7, the rotor holder 21A includes a
rotor holder through hole 231A in the rotor holder bottom portion
23A penetrating in the axial direction. A plurality of the rotor
holder through holes 231A are formed in the rotor holder bottom
portion 23A. Each of the rotor holder through holes 231A is a
through hole whose longitudinal direction is oriented in the radial
direction. A plurality of the rotor holder through holes 231A are
formed along the circumferential direction. In the present
embodiment, eight rotor holder through holes are formed at equal
intervals along the circumferential direction. Note that the rotor
holder through hole 231A may have a different shape or arrangement,
and the number thereof may be less than eight or more than eight.
This makes it possible to efficiently guide the air flowing into
the motor cover 80 toward the inside of the motor 10A, and to
effectively cool parts such as the coil 33 and the stator core
31.
[0076] The bearing housing 34 and the attachment plate 35A are both
made of metal. This makes it possible to improve the thermal
conductivity of the bearing housing 34 and the attachment plate
35A. Hence, it is possible to more effectively cool the stator unit
30.
[0077] A lower side balance correcting portion 24A is formed by a
recessed portion or the through hole disposed in the outer surface
of the rotor holder 21A. The recessed portion or the through hole
is formed axially asymmetrically. In the present embodiment, the
lower side balance correcting portion 24A is a recessed portion
formed in the rotor holder bottom portion 23A. If the recessed
portion is formed at a preferable location of the rotor holder
bottom portion 23A, it is possible to partially remove the rotor
holder 21A, making it possible to correct the balance of the
assembly of the impeller 50 and the motor 10A. Note that the lower
side balance correcting portion 24A may be a through hole or a
cutout, for example, and may be formed at more than one location.
In addition, the lower side balance correcting portion 24 may be
formed in a rotor holder cylindrical portion 22. In the above
configuration, a so-called minus balance makes it possible to
correct the balance of the assembly.
[0078] Next, a description is provided for an air blowing apparatus
1B according to an exemplary third embodiment of the application of
the present disclosure. In the description of the air blowing
apparatus 1B according to the third embodiment, the same
explanation as that of the air blowing apparatus 1 of the first
embodiment is omitted. In addition, the parts and the members
having the same configurations as those of the first embodiment may
be given the same reference signs as those of the first
embodiment.
[0079] FIG. 8 is a vertical cross-sectional view of the air blowing
apparatus 1B according to the third embodiment. The air blowing
apparatus 1B includes a motor 10B, an impeller 50B, and an impeller
cover 60B. The motor 10B includes a shaft 11B which is disposed
along the central axis J extending vertically. The impeller 50B is
fixed to the shaft 11B. The impeller cover 60B surrounds the upper
side and the outer side in the radial direction of the impeller 50B
and includes a suction inlet 61B at the center.
[0080] FIGS. 9 and 10 are a perspective view and a plan view of the
impeller 50B according to the third embodiment, respectively. With
reference to FIGS. 8, 9, and 10, the impeller 50B includes multiple
movable vanes 51B, a lower shroud 52B, and an upper shroud 53B. The
multiple movable vanes 51B are disposed in the circumferential
direction. In the impeller 50B, the number of movable vanes 51B is
ten, including five main vanes having a length long in the radial
direction and five auxiliary vanes having a length short in the
radial direction disposed alternately. The inner end in the radial
direction of each of the main vanes is disposed on the inner side
of the inner end in the radial direction of the upper shroud
53B.
[0081] The lower shroud 52B is disposed on the lower side of the
movable vanes 51B. The inner portion in the radial direction of the
lower shroud 52B protrudes upward in the axial direction compared
to the outer portion thereof, and the upper surface of the lower
shroud 52B is smoothly curved downward and outward toward the outer
side in the radial direction. The upper shroud 53B includes a
through hole 531B which is disposed higher than the movable vanes
51B and which penetrates in the axial direction.
[0082] A blower case 82B is disposed on the lower side of the
impeller cover 60B. The blower case 82B has a substantially
cylindrical shape extending in the axial direction. The lower end
portion of the impeller cover 60B is fixed to the upper end portion
of the blower case 82B. The blower case 82B is connected to the
motor cover 80B by multiple static vanes 72B disposed in the
circumferential direction. The motor cover 80B has a tubular shape
extending in the axial direction and opened downward. The blower
case 82B, the static vanes 72B, and the motor cover 80B form a
single member. The impeller cover 60B, the blower case 82B, and the
motor cover 80B form a flow path. To be more specific, the air
blowing apparatus 1B further includes the motor cover 80B which is
disposed on the lower side of the impeller cover 60B and which is
disposed on the outer side in the radial direction of the motor
10B. The multiple static vanes 72B are disposed in the
circumferential direction on the outer surface in the radial
direction of the motor cover 80B. In other words, the multiple
static vanes 72B are disposed in the flow path on the outer side in
the radial direction of the motor cover 80B. This makes it possible
to guide the air flowing in the flow path smoothly downward. Thus,
the air discharged from the impeller 50B is guided into the flow
path along the inner surface of the impeller cover 60B and then
smoothly discharged downward in the axial direction. As opposed to
the case of the air blowing apparatus 1, the air flows straightly
in the flow path in the air blowing apparatus 1B. For this reason,
the flow rate does not easily reduce, improving the air blow
efficiency of the air blowing apparatus 1B.
[0083] The upper shroud 53B includes a first raised portion 541B
and a second raised portion 542B. Each of the first raised portion
541B and the second raised portion 542B is an annular portion. The
first raised portion 541B protrudes upward from the upper surface
of the upper shroud 53B, and extends in the circumferential
direction. The second raised portion 542B protrudes upward from the
upper surface of the upper shroud 53B, and extends in the
circumferential direction. The second raised portion 542B is
disposed on the outer side in the radial direction of the first
raised portion 541B.
[0084] The clearance in the axial direction between the lower
surface of the impeller cover 60B and at least one of the first
raised portion 541B and the second raised portion 542B is smaller
than the clearance in the axial direction between the lower surface
of the impeller cover 60B and the upper shroud 53B on the inner
side in the radial direction of the first raised portion 541B. In
other words, the clearance in the axial direction between the lower
surface of the impeller cover 60B and the upper surface of the
upper shroud 53B is small in a region where the first raised
portion 541B or the second raised portion 542B is formed. This
makes it possible to obtain a labyrinth effect between the impeller
cover 60B and the first raised portion 541B or the second raised
portion 542B and to reduce the risk that the air discharged from
the impeller 50B could flow into the clearance between the impeller
cover 60B and the upper shroud 53B. As a result, the efficiency of
the air blowing apparatus improves.
[0085] The upper end of the first raised portion 541B is disposed
higher than the upper end of the second raised portion 542B. In
other words, the first raised portion 541B protrudes higher than
the second raised portion 542B. This makes it possible to reduce
the clearance in the axial direction between the first raised
portion 541B and the lower surface of the impeller cover 60B.
Hence, the labyrinth effect improves. In addition, it is possible
to reduce the weight of the outer portion in the radial direction
of the impeller 50B compared to the case where the second raised
portion 542B more protrudes upward. As a result, the rotational
balance is enhanced and the vibration of the impeller 50B is
reduced. Additionally, the second raised portion 542B is disposed
on the outer edge in the radial direction of the upper shroud 53B.
This makes it possible to more reduce the risk that the air
discharged from the impeller 50B could flow onto the upper surface
of the upper shroud 53B.
[0086] The upper shroud 53B includes multiple upper shroud wall
portions 543B which are disposed in the circumferential direction
and which connect the first raised portion 541B and the second
raised portion 542B together. This improves the rigidity of the
upper shroud 53B. In addition, the inner end in the radial
direction of each of the upper shroud wall portions 543B is located
in front of the corresponding outer end in the radial direction of
the upper shroud wall portion 543B in the rotational direction R of
the impeller 50B. Thus, when the impeller 50B rotates, the air
which has flowed onto the upper surface of the impeller 50B is
discharged by the upper shroud wall portions 543B outward in the
radial direction. Hence, the labyrinth function in the clearance
between the upper shroud 53B and the lower surface of the impeller
cover 60B improves.
[0087] The height in the axial direction of the upper end of the
upper shroud wall portion 543B is equal to the height in the axial
direction of the upper end of the first raised portion 541B. Thus,
in the impeller 50B, the upper shroud wall portion 543B and the
first raised portion 541B have the same height, and both of them
are higher than the second raised portion 542B. As a result, if the
upper shroud wall portion 543B is higher, it is possible to more
efficiently discharge the air in the space formed between the
impeller cover 60B and the upper surface of the upper shroud 53B to
the outside.
[0088] In the air blowing apparatus 1B, the number of upper shroud
wall portions 543B is 11, and the number of movable vanes 51B is
10. In other words, the number of upper shroud wall portions 543B
and the number of movable vanes 51B are different from each other.
Thus, the number of hissing noises produced from the movable vanes
51B differs from the number of hissing noises produced from the
upper shroud wall portions 543B over the period of one rotation of
the impeller 50B about the central axis J. As a consequence, it is
possible to reduce the risk that the hissing noise of the movable
vanes 51B and the hissing noise of the upper shroud wall portion
543B occur at the same time to produce a loud noise. Particularly
in the case of the air blowing apparatus 1B, the number of upper
shroud wall portions 543B and the number of movable vanes 51B are
mutually prime. Thus, it is possible to further reduce the risk
that the hissing noise by the upper shroud wall portions 543B and
the hissing noise by the movable vanes 51B occur at the same time
during the period of one rotation of the impeller 50B, making it
possible to more suppress noise. In addition, at least one of the
upper shroud wall portions 543B is disposed between adjacent
movable vanes 51B in the circumferential direction. To put it
differently, at least one of the outer ends in the radial direction
of the upper shroud wall portions 543B is disposed in the
circumferential direction between the outer ends in the radial
direction of adjacent movable vanes 51B. Hence, the balance of the
upper shroud 53B is enhanced and the rigidity as a whole improves
in a well balanced manner. In addition, when the impeller 50B
rotates, hissing noise by the upper shroud wall portions 543B and
hissing noise by the movable vanes 51B are prevented from occurring
at the same time. Therefore, it is possible to reduce the noise by
the impeller 50B.
[0089] The impeller 50B includes an upper side balance correcting
portion 54B included in the upper shroud 53B. To be more precise,
the upper shroud 53B includes multiple upper side balance
correcting portions 54B formed by the first raised portion 541B,
the second raised portion 542B, and the multiple upper shroud wall
portions 543B. In other words, each of the upper side balance
correcting portion 54B is a space which is formed by the first
raised portion 541B, the second raised portion 542B, the upper
shroud wall portions 543B, and the upper surface of the upper
shroud 53B and which is opened upward in the axial direction. At
least one of the upper side balance correcting portions 54B is
provided with a weight 544B. Thus, it is possible to correct the
dynamic balance of the impeller 50B.
[0090] Note that the dynamic balance of the impeller 50B may be
corrected by a different method. For example, the dynamic balance
of the impeller 50B may be corrected by cutting at least one of the
first raised portion 541B, the second raised portion 542B, and the
upper shroud wall portion 543B. In other words, the shape of the
upper side balance correcting portion 54B may be asymmetric with
respect to the central axis J. This makes it possible to correct
the dynamic balance of the impeller 50B even in the case where
members such as the weight 544B are lacked.
[0091] The motor 10B includes a stator unit 30B, a rotor unit 20B,
and bearings 40B. The stator unit 30B faces the rotor unit 20B in
the radial direction. The stator unit 30B includes a bearing
housing 34B, a stator core 31B which is fixed to the outer surface
in the radial direction of the bearing housing 34B, and a circuit
board 37B which is fixed to the outer surface in the radial
direction of the bearing housing 34B above the stator core 31B.
Lead wire electrically connected to the circuit board 37B is wound
around the stator core 31B using an insulator (not illustrated). In
this way, a coil 33B is formed. The bearings 40B are fixed to the
inner surface of the bearing housing 34B. Each of the bearings 40B
supports the shaft 11B such that the shaft 11B can rotate relative
to the stator unit 30B. The upper end portion of the bearing
housing 34B is fixed to the motor cover 80B.
[0092] The stator unit 30B includes: the tubular bearing housing
34B which holds the bearings 40B on the inner surface thereof; and
an attachment plate 35B which spreads in a direction perpendicular
to the shaft 11B on the outer side of the bearing housing 34B. The
attachment plate 35B is fixed to the motor cover 80B. This makes it
possible to fix the motor 10B of an outer rotor type to the motor
cover 80B. In other words, in the case of the motor 10B of an outer
rotor type, it is impossible to fix the rotor holder 21B to the
motor cover 80B if a rotor holder bottom portion 23B to be
described later is disposed higher than the stator core 31B.
However, in the air blowing apparatus 1B, it is possible to fix the
attachment plate 35B to the motor cover 80B because the rotor
holder bottom portion 23B is disposed lower than the stator core
31B, and the bearing housing 34B and the attachment plate 35B are
disposed higher than the stator core 31B. Note that although the
bearing housing 34B and the attachment plate 35B form a single
member, they may be separate members. In addition, although the
attachment plate 35B is fixed to the motor cover 80B by press
fitting, a different fixing method may be employed.
[0093] The motor cover 80B includes a motor cover through hole 73B
penetrating in the axial direction. The motor cover through hole
73B is a circular hole centered at the central axis J. At least a
portion of the bearing housing 34B is fitted to the motor cover
through hole 73B. In detail, the attachment plate 35B formed on the
upper end portion of the bearing housing 34B is fixed to the inner
end portion in the radial direction of the motor cover 80B. This
makes it possible to fix the bearing housing 34B and the motor
cover 80B coaxially with the central axis J.
[0094] The motor 10B includes a circuit board 37B which is disposed
on the lower side of the attachment plate 35B and on the upper side
of the rotor holder 21B. The circuit board 37B is fixed to the
outer side in the radial direction of the bearing housing 34B and
is disposed in the axial direction between the lower surface of the
attachment plate 35B and the upper end of the rotor holder 21B. The
circuit board 37B includes a lead wire (not illustrated)
electrically connected to an external power supply. The electric
current supplied through the lead line is supplied to the coil via
the circuit board 37B. The motor cover 80B includes a motor cover
through hole 881B through which the lead line is inserted at least
one location in the circumferential direction. This makes it
possible to extend the lead line to the outside of the motor cover
80B.
[0095] The rotor unit 20B includes a lidded cylindrical rotor
holder 21B which is fixed to the shaft 11B and which is opened
upward. The rotor holder 21B includes: a rotor holder bottom
portion 23B which is fixed to the shaft 11B; and a substantially
cylindrical rotor holder cylindrical portion 22B which extends
upward from the outer side in the radial direction of the rotor
holder bottom portion 23B. The rotor holder bottom portion 23B is
disposed on the lower side of the rotor holder cylindrical portion
22B. A substantially cylindrical magnet 25B is fixed to the inner
surface of the rotor holder cylindrical portion 22B.
[0096] The rotor holder cylindrical portion 22B further includes a
rotor holder flange portion 27B which extends outward in the radial
direction from the upper end portion of the rotor holder
cylindrical portion 22B. The rotor holder flange portion 27B forms
a lower side balance correcting portion 24B. In other words, the
rotor holder 21B includes the lower side balance correcting portion
24B. Thus, the lower side balance correcting portion 24B is formed
on the outer side in the radial direction of the motor 10B. In
other words, the rotor holder 21B includes: the rotor holder
cylindrical portion 22B; the rotor holder bottom portion 23B which
is disposed on the lower side of the rotor holder cylindrical
portion 22B; and the lower side balance correcting portion 24B
which is included in at least one of the rotor holder cylindrical
portion 22B and the rotor holder bottom portion 23B. A weight 264B,
for example, is fixed to the lower side balance correcting portion
24B. This makes it possible to correct the rotational balance of
the motor 10B. Moreover, if both the upper side balance correcting
portion 54B and the lower side balance correcting portion 24B
correct the rotational balance, it is possible to correct the
two-plane balance of the single rotating body made up of the motor
10B, the shaft 11B, and the impeller 50B.
[0097] Note that although the lower side balance correcting portion
24B is formed using a motor of an outer rotor type in the air
blowing apparatus 1B, the motor 10B may be of an inner rotor type.
In addition, the lower side balance correcting portion 24B may be
formed by a portion other than the rotor holder flange portion 27B.
For example, the dynamic balance of the rotor unit 20B may be
corrected by partially cutting the rotor holder cylindrical portion
22B to reduce the weight of that portion.
[0098] FIG. 11 is a perspective view illustrating a vacuum cleaner
100. The vacuum cleaner 100 includes the air blowing apparatus
described above. This makes it possible to improve the air blow
efficiency of the air blowing apparatus mounted on the vacuum
cleaner 100.
[0099] Exemplary embodiments of the present disclosure have been
described above. However, the constituents, combinations thereof,
and the like in the first embodiment and the second embodiment are
examples. It is possible to add, omit, substitute, and modify the
constituents within the scope not departing from the gist of the
present disclosure. In addition, the present disclosure is not
limited to the embodiments.
[0100] Features of the above-described preferred embodiments and
the modifications thereof may be combined appropriately as long as
no conflict arises.
[0101] While preferred embodiments of the present disclosure have
been described above, it is to be understood that variations and
modifications will be apparent to those skilled in the art without
departing from the scope and spirit of the present disclosure. The
scope of the present disclosure, therefore, is to be determined
solely by the following claims.
* * * * *