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United States Patent Application 20170356464
Kind Code A1
Hino; Yuko ;   et al. December 14, 2017

BLOWER APPARATUS

Abstract

This blower apparatus includes an air blowing portion including a plurality of flat plates arranged with an axial gap defined between adjacent ones of the flat plates; a motor portion arranged to rotate the air blowing portion; and a housing arranged to house the air blowing portion and the motor portion. The housing includes an air inlet arranged to pass through a portion of the housing in an axial direction above the air blowing portion, and an air outlet arranged to face in a radial direction radially outside of the air blowing portion. One of the flat plates includes a projecting portion arranged to project upward and/or downward, and another one of the flat plates includes an opposing portion arranged to be circumferentially opposed to the projecting portion. Relative circumferential positions of the flat plates can be easily fixed by the opposing portion.


Inventors: Hino; Yuko; (Kyoto, JP) ; Yoo; Seung-Sin; (Kyoto, JP) ; Tsukamoto; Tomoyuki; (Kyoto, JP) ; Makita; Akihiko; (Kyoto, JP)
Applicant:
Name City State Country Type

Nidec Corporation

Kyoto

JP
Assignee: Nidec Corporation
Kyoto
JP

Family ID: 1000002682478
Appl. No.: 15/615143
Filed: June 6, 2017


Related U.S. Patent Documents

Application NumberFiling DatePatent Number
62347380Jun 8, 2016

Current U.S. Class: 1/1
Current CPC Class: F04D 29/626 20130101; F04B 35/04 20130101; F04B 17/00 20130101; F04D 29/083 20130101; F04D 25/06 20130101
International Class: F04D 29/62 20060101 F04D029/62; F04D 29/08 20060101 F04D029/08; F04D 25/06 20060101 F04D025/06; F04B 35/04 20060101 F04B035/04

Foreign Application Data

DateCodeApplication Number
Mar 15, 2017JP2017-049386

Claims



1. A blower apparatus comprising: an air blowing portion arranged to rotate about a central axis extending in a vertical direction; a motor portion arranged to rotate the air blowing portion; and a housing arranged to house the air blowing portion and the motor portion; wherein the housing includes: an air inlet arranged above the air blowing portion, and arranged to pass through a portion of the housing in an axial direction; and an air outlet arranged to face in a radial direction at least one circumferential position radially outside of the air blowing portion; the air blowing portion includes a plurality of flat plates arranged in the axial direction with an axial gap defined between adjacent ones of the flat plates; one of the flat plates includes a projecting portion arranged to project upward or downward or both ways; and another one of the flat plates includes an opposing portion arranged to be circumferentially opposed to the projecting portion.

2. The blower apparatus according to claim 1, wherein the flat plates include: a first positioning flat plate including the projecting portion, the projecting portion being arranged to project upward; and one or a plurality of second positioning flat plates arranged upwardly adjacent, to the first positioning flat plate, each second positioning flat plate including a cut in which the projecting portion is fitted.

3. The blower apparatus according to claim 1, wherein the flat plates include: a first positioning flat plate including the projecting portion, the projecting portion being arranged to project upward; and one or a plurality of second positioning flat plates arranged upwardly adjacent, to the first positioning flat plate, each second positioning flat plate including a positioning hole being a through hole in which the projecting portion is fitted.

4. The blower apparatus according to claim 3, wherein the flat plates include the plurality of second positioning flat plates; the plurality of second positioning flat plates are arranged to have smaller diameters of the positioning holes as the plurality of second positioning flat plates are arranged at higher positions; and the projecting portion is arranged to become smaller in a cross-sectional area at higher positions.

5. The blower apparatus according to claim 1, wherein at least one of the flat plates includes an air hole arranged to pass therethrough in the axial direction; and the projecting portion is arranged radially outward of the air hole.

6. The blower apparatus according to claim 3, wherein each second positioning flat plate includes: an inner annular portion being annular, and centered on the central axis; an outer annular portion being annular, centered on the central axis, and arranged radially outside of the inner annular portion; a plurality of ribs each of which is arranged to radially join the inner annular portion and the outer annular portion to each other; and a plurality of air holes each of which is surrounded by the inner annular portion, the outer annular portion, and two circumferentially adjacent ones of the ribs, and is arranged to pass through the second positioning flat plate in the axial direction; and each positioning hole is defined in one of the ribs.

7. The blower apparatus according to claim 3, wherein each second positioning flat plate is annular and includes a central hole being a circular through hole; and the second positioning flat plate includes an inner edge portion defining the central hole, and a radial gap between the inner edge portion and the motor portion defines an air hole.

8. The blower apparatus according to claim 7, wherein the air blowing portion further includes a spacer arranged between axially adjacent ones of the flat plates; the spacer is arranged in an annular shape around the projecting portion; and the axially adjacent ones of the flat plates are fixed to each other through the spacer.

9. The blower apparatus according to claim 1, wherein the air blowing portion further includes a spacer arranged between axially adjacent ones of the flat plates; and the axially adjacent ones of the flat plates are fixed to each other through the spacer.

10. The blower apparatus according to claim 8, wherein the spacer is defined by a heat-welding sheet.

11. The blower apparatus according to claim 1, wherein a center of the air inlet is arranged to coincide with the central axis.

12. The blower apparatus according to claim 1, wherein the motor portion includes: a stationary portion including an armature and a bearing housing; and a rotating portion including a shaft, a bearing member, and a magnet arranged radially opposite to the armature; the bearing housing and a combination of the shaft and the bearing member are arranged to have a lubricating fluid therebetween; the bearing housing and the rotating portion are arranged to together define a gap defining a seal portion therebetween, the seal portion having a surface of the lubricating fluid defined therein; and in the seal portion, a distance between the bearing housing and the rotating portion is arranged to increase with increasing distance from the surface of the lubricating fluid.

13. The blower apparatus according to claim 1, wherein the motor portion includes: a stationary portion including an armature; a rotating portion including a magnet arranged radially opposite to the armature; and a ball bearing arranged to connect the rotating portion to the stationary portion such that the rotating portion is rotatable with respect to the stationary portion.

14. The blower apparatus according to claim 1, wherein the housing includes a plurality of the air outlets at a plurality of circumferential positions.
Description



BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The present invention relates to a blower apparatus.

2. Description of the Related Art

[0002] A centrifugal blower apparatus which generates an air flow traveling radially outward by rotating an impeller including a plurality of blades is known. A known blower apparatus including an impeller is described in, for example, JP-A 2008-88985.

[0003] In the blower apparatus described in JP-A 2008-88985, a plurality of blades referred to as fan blades push surrounding gas to generate air flows traveling radially outward.

SUMMARY OF THE INVENTION

[0004] In recent years, there has still been a demand for reductions in the size and thickness of electronic devices. Accordingly, there has also been a demand for a reduction in the thickness of blower apparatuses used to cool the interiors of the electronic devices.

[0005] Here, in the case where an impeller is used to generate air flows, as in the blower apparatus described in JP-A 2008-88985, air flows pushed by a blade leak from axially upper and lower ends of the blade while the impeller is rotating. As a result, air pressure is lower at the axially upper and lower ends of the blade than in the vicinity of an axial middle of the blade. Accordingly, a reduction in the thickness of the blower apparatus, which involves a reduction in the axial dimension of the impeller, will result in a failure to secure sufficient air blowing efficiency.

[0006] Accordingly, instead of an impeller including a plurality of blades, a plurality of flat plates arranged in an axial direction with an axial gap defined between adjacent ones of the flat plates may be used as an air blowing portion of a blower apparatus. In such a blower apparatus, once the air blowing portion starts rotating, an air flow traveling radially outward is generated in the axial gap between the adjacent flat plates by viscous drag of surfaces of the flat plates and a centrifugal force. Thus, gas supplied through an air inlet and an air hole travels radially outwardly of the air blowing portion. Since the air flow is generated between the flat plates, the air flow does not easily leak upwardly or downwardly, and thus, an improvement in air blowing efficiency is achieved. Accordingly, a reduced thickness of the above blower apparatus would not result in a significant reduction in the air blowing efficiency. In addition, the above blower apparatus is superior to a comparable centrifugal fan including an impeller in terms of being silent.

[0007] However, the blower apparatus including the plurality of flat plates changes in air blowing performance depending on relative circumferential positions of the flat plates. Therefore, positioning of the flat plates with respect to each other is important to achieve desired air blowing performance. Accordingly, there is a demand for quick and secure positioning of the flat plates with respect to each other.

[0008] An object of the present invention is to provide a technique for enabling flat plates to be easily positioned with respect to each other in a process of manufacturing a blower apparatus including the flat plates.

[0009] A blower apparatus according to a preferred embodiment of the present invention includes an air blowing portion arranged to rotate about a central axis extending in a vertical direction; a motor portion arranged to rotate the air blowing portion; and a housing arranged to house the air blowing portion and the motor portion. The housing includes an air inlet arranged above the air blowing portion, and arranged to pass through a portion of the housing in an axial direction; and an air outlet arranged to face in a radial direction at least one circumferential position radially outside of the air blowing portion. The air blowing portion includes a plurality of flat plates arranged in the axial direction with an axial gap defined between adjacent ones of the flat plates. One of the flat plates includes a projecting portion arranged to project upward or downward or both ways. Another one of the flat plates includes an opposing portion arranged to be circumferentially opposed to the projecting portion.

[0010] According to the above preferred embodiment of the present invention, relative circumferential positions of the flat plates can be easily fixed by the opposing portion. Accordingly, desired air blowing performance can be achieved, and an assemblage in a manufacturing process can be quickly performed.

[0011] The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a perspective view of a blower apparatus according to a first preferred embodiment of the present invention.

[0013] FIG. 2 is a top view of the blower apparatus according to the first preferred embodiment.

[0014] FIG. 3 is a sectional view of the blower apparatus according to the first preferred embodiment.

[0015] FIG. 4 is an exploded perspective view of the blower apparatus according to the first preferred embodiment.

[0016] FIG. 5 is a partial sectional view of the blower apparatus according to the first preferred embodiment.

[0017] FIG. 6 is an exploded perspective view of a plurality of flat plates according to the first preferred embodiment.

[0018] FIG. 7 is a top view of the flat plates according to the first preferred embodiment.

[0019] FIG. 8 is a partial sectional view of a blower apparatus according to a modification of the first preferred embodiment.

[0020] FIG. 9 is an exploded perspective view of a plurality of flat plates of the blower apparatus according to a modification of the first preferred embodiment.

[0021] FIG. 10 is a partial sectional view of a blower apparatus according to a modification of the first preferred embodiment.

[0022] FIG. 11 is an exploded perspective view of a plurality of flat plates of a blower apparatus according to a modification of the first preferred embodiment.

[0023] FIG. 12 is a partial sectional view of a blower apparatus according to a modification of the first preferred embodiment.

[0024] FIG. 13 is a top view of a blower apparatus according to a modification of the first preferred embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, blower apparatuses according to preferred embodiments of the present, invention will be described. It is assumed herein that a side on which an upper plate portion is arranged with respect to a lower plate portion is an upper side, and the shape of each member or portion and relative positions of different members or portions will be described based on the above assumption. It should be noted, however, that the above definition of the upper and lower sides is not meant to restrict in any way the orientation of a blower apparatus according to any preferred embodiment of the present invention at the time of manufacture or when in use.

1. FIRST PREFERRED EMBODIMENT

[0026] 1-1. Structure of Blower Apparatus

[0027] FIG. 1 is a perspective view of a blower apparatus 1 according to a first preferred embodiment of the present invention. FIG. 2 is a top view of the blower apparatus 1. FIG. 3 is a sectional view of the blower apparatus 1 taken along line A-A in FIG. 2. FIG. 4 is an exploded perspective view of the blower apparatus 1. FIG. 5 is a partial sectional view of the blower apparatus 1. The blower apparatus 1 is a centrifugal blower apparatus designed to generate an air flow traveling radially outward by rotating an air blowing portion 40. The blower apparatus 1 is, for example, installed in an electronic device, such as, for example, a personal computer, to cool an interior thereof. Note that blower apparatuses according to preferred embodiments of the present invention may be used for other purposes.

[0028] Referring to FIGS. 1 to 4, the blower apparatus 1 includes a housing 20, a motor portion 30, and the air blowing portion 40.

[0029] The housing 20 is a case arranged to house the motor portion 30 and the air blowing portion 40. The housing 20 includes a lower plate portion 21, a side wall portion 22, and an upper plate portion 23.

[0030] The lower plate portion 21 is arranged to define a bottom portion of the housing 20. The lower plate portion 21 is arranged to extend radially below the air blowing portion 40 to cover at least a portion of a lower side of the air blowing portion 40. In addition, the lower plate portion 21 is arranged to support the motor portion 30.

[0031] The side wall portion 22 is arranged to extend upward from the lower plate portion 21. The side wall portion 22 is arranged to cover a lateral side of the air blowing portion 40 between the lower plate portion 21 and the upper plate portion 23. In addition, the side wall portion 22 includes an air outlet 201 arranged to face in a radial direction at one circumferential position. In the present preferred embodiment, the lower plate portion 21 and the side wall portion 22 are defined integrally with each other. Note that the lower plate portion 21 and the side wall portion 22 may alternatively be defined by separate members.

[0032] The upper plate portion 23 is arranged to define a cover portion of the housing 20. The upper plate portion 23 is arranged to extend radially above the lower plate portion 21. In addition, the upper plate portion 23 includes an air inlet 202 arranged to pass therethrough in an axial direction. In other words, the upper plate portion 23 includes an inner edge portion 231 arranged to define the air inlet 202. The air inlet 202 is, for example, circular and is centered on a central axis 9 in a plan view.

[0033] The motor portion 30 is a driving portion arranged to rotate the air blowing portion 40. Referring to FIG. 5, the motor portion 30 includes a stationary portion 31 and a rotating portion 32. The stationary portion 31 is fixed to the lower plate portion 21. The stationary portion 31 is thus arranged to be stationary relative to the housing 20. The rotating portion 32 is supported to be rotatable about the central axis 9 with respect to the stationary portion 31.

[0034] The stationary portion 31 includes a stator fixing portion 311, a stator 312, and a bearing housing 313.

[0035] The stator fixing portion 311 is fitted in a fixing hole 211 defined in the lower plate portion 21. As a result, the stator fixing portion 311 is fixed to the lower plate portion 21. The stator fixing portion 311 is arranged to extend upward from the fixing hole 211 to assume a cylindrical shape with the central axis 9 as a center thereof. The stator 312 is fixed to an outer circumferential portion of an upper portion of the stator fixing portion 311.

[0036] The stator 312 is an armature arranged to generate magnetic flux in accordance with electric drive currents supplied from an external source. The stator 312 is arranged to annularly surround the central axis 9, which extends in a vertical direction. The stator 312 includes, for example, an annular stator core defined by laminated steel sheets, and conducting wires wound around the stator core.

[0037] The bearing housing 313 is a member being cylindrical and having a closed bottom. Specifically, the bearing housing 313 includes a disk-shaped bottom portion, and a cylindrical portion arranged to extend upward from the bottom portion. The bearing housing 313 is fixed to an inner circumferential surface of the stator fixing portion 311.

[0038] The rotating portion 32 includes a shaft 321, a hub 322, a bearing member 323, and a magnet 324.

[0039] The shaft 321 is a member arranged to extend along the central axis 9. The shaft 321 according to the present preferred embodiment includes a columnar portion arranged inside of a first cylindrical portion 512, which will be described below, and arranged to extend with the central axis 9 as a center thereof, and a disk-shaped portion arranged to extend radially from a lower end portion of the columnar portion.

[0040] The hub 322 is fixed to the shaft 321. The hub 322 is made up of a hub body member 51 and a flange member 52.

[0041] The hub body member 51 includes a first top plate portion 511, the first cylindrical portion 512, a second cylindrical portion 513, and a magnet holding portion 514.

[0042] The first top plate portion 511 is a disk-shaped portion arranged to extend radially with the central axis 9 as a center thereof. The first top plate portion 511 is arranged above the stator 312. The first top plate portion 511 has a recessed portion 515 recessed from an upper surface thereof at an outer edge portion thereof.

[0043] The first cylindrical portion 512 is arranged to extend downward from the first top plate portion 511 to assume a cylindrical shape with the central axis 9 as a center thereof. The columnar portion of the shaft 321 is housed in the first cylindrical portion 512. In addition, the shaft 321 is fixed to the first cylindrical portion 512.

[0044] The second cylindrical portion 513 is arranged to extend downward from the first top plate portion 511 to assume a cylindrical shape with the central axis 9 as a center thereof. The second cylindrical portion 513 is arranged to have an Inside diameter greater than an outside diameter of the first cylindrical portion 512. In other words, the second cylindrical portion 513 is arranged radially outside of the first cylindrical portion 512.

[0045] The magnet holding portion 514 is arranged to extend downward from a radially outer end of the first top plate portion 511 to assume a cylindrical shape with the central axis 9 as a center thereof. The magnet holding portion 514 is arranged radially outside of the stator 312. The magnet 324 is fixed to an inner circumferential surface of the magnet holding portion 514.

[0046] The flange member 52 includes an outer wall portion 521, a second top plate portion 522, and a flat plate holding portion 523.

[0047] The outer wall portion 521 is a cylindrical portion arranged to extend in the vertical direction with the central axis 9 as a center thereof. The outer wall portion 521 is arranged to extend along an outer circumferential surface of the magnet holding portion 514 of the hub body member 51.

[0048] The second top plate portion 522 is arranged to extend radially inward from an upper end portion of the outer wall portion 521 to assume the shape of a circular ring. The second top plate portion 522 is arranged in the recessed portion 515, which is defined in the upper surface of the first top plate portion 511 of the hub body member 51. In addition, the upper surface of the first top plate portion 511 and an upper surface of the second top plate portion 522 are arranged at the same axial position.

[0049] The flat plate holding portion 523 is arranged to extend radially outward from a lower end portion of the outer wall portion 521. The flat plate holding portion 523 is arranged to hold the air blowing portion 40 on a radially outer side of the magnet holding portion 514 of the hub body member 51. In the present preferred embodiment, the air blowing portion 40 is mounted on an upper surface of the flat plate holding portion 523. The flat plate holding portion 523 is thus arranged to hold a plurality of flat plates 410 included in the air blowing portion 40.

[0050] The bearing member 323 is a cylindrical member arranged to extend in the vertical direction with the central axis 9 as a center thereof. The bearing member 323 is arranged to extend along an outer circumferential surface of the first cylindrical portion 512 of the hub body member 51. In addition, the bearing member 323 is fixed to the outer circumferential surface of the first cylindrical portion 512. The cylindrical portion of the bearing housing 313 is arranged radially outside of the bearing member 323 and radially inside of the second cylindrical portion 513 of the hub body member 51.

[0051] The magnet 324 is fixed to the inner circumferential surface of the magnet holding portion 514 of the hub body member 51. In addition, the magnet 324 is arranged radially outside of the stator 312. The magnet 324 according to the present preferred embodiment is in the shape of a circular ring. A radially inner surface of the magnet 324 is arranged radially opposite to the stator 312 with a slight gap therebetween. In addition, an inner circumferential surface of the magnet 324 includes north and south poles arranged to alternate with each other in a circumferential direction. Note that a plurality of magnets may be used in place of the magnet 324 in the shape of a circular ring. In the case where the plurality of magnets are used, the magnets are arranged in the circumferential direction such that north and south poles of the magnets alternate with each other.

[0052] As illustrated in an enlarged view in FIG. 5, a lubricating fluid 300 is arranged between the bearing housing 313 and a combination of the shaft 321, the bearing member 323, and the hub body member 51. A polyolester oil or a diester oil, for example, is used as the lubricating fluid 300. The shaft 321, the hub 322, and the bearing member 323 are supported to be rotatable with respect to the bearing housing 313 through the lubricating fluid 300. Thus, in the present preferred embodiment, the bearing housing 313, which is a component of the stationary portion 31, the combination of the shaft 321, the bearing member 323, and the hub body member 51, each of which is a component of the rotating portion 32, and the lubricating fluid 300 together define a fluid dynamic bearing.

[0053] A surface of the lubricating fluid 300 is defined in a seal portion 301, which is a gap between an outer circumferential surface of the bearing housing 313 and an inner circumferential surface of the second cylindrical portion 513 of the hub body member 51. In the seal portion 301, the distance between the outer circumferential surface of the bearing housing 313 and the inner circumferential surface of the second cylindrical portion 513 is arranged to increase with decreasing height. In other words, in the seal portion 301, the distance between the outer circumferential surface of the bearing housing 313 and the inner circumferential surface of the second cylindrical portion 513 is arranged to increase with increasing distance from the surface of the lubricating fluid 300. Since the radial width of the seal portion 301 thus increases with decreasing height, the lubricating fluid 300 is attracted upward in the vicinity of the surface of the lubricating fluid 300. This reduces the likelihood that the lubricating fluid 300 will leak out of the seal portion 301.

[0054] Use of the fluid dynamic bearing as a bearing mechanism that connects the stationary portion 31 and the rotating portion 32 allows the rotating portion 32 to rotate stably. Thus, the likelihood of an occurrence of an unusual sound from the motor portion 30 can be reduced.

[0055] Once electric drive currents are supplied to the stator 312 in the motor portion 30 as described above, magnetic flux is generated around the stator 312. Then, interaction between the magnetic flux of the stator 312 and magnetic flux of the magnet 324 produces a circumferential torque between the stationary portion 31 and the rotating portion 32, so that the rotating portion 32 is caused to rotate about the central axis 9 with respect to the stationary portion 31. The air blowing portion 40, which is held by the flat plate holding portion 523 of the rotating portion 32, is caused to rotate about the central axis 9 together with the rotating portion 32.

[0056] Referring to FIGS. 4 and 5, the air blowing portion 40 includes the plurality of flat plates 410 and a plurality of spacers 420. The flat plates 410 and the spacers 420 are arranged to alternate with each other in the axial direction. In addition, adjacent ones of the flat plates 410 and the spacers 420 are fixed to each other through, for example, adhesion. That is, axially adjacent ones of the flat plates 410 are fixed to each other through one of the spacers 420.

[0057] Referring to FIGS. 4 and 5, in the present preferred embodiment, the flat plates 410 include a top flat plate 411, which is arranged at the highest position, a bottom flat plate 412, which is arranged at the lowest position, and four intermediate flat plates 413, 414, 415, and 416, which are arranged below the top flat plate 411 and above the bottom flat plate 412. That is, the number of flat plates 410 included in the air blowing portion 40 according to the present, preferred embodiment is six. The flat plates 410 are arranged in the axial direction with an axial gap 400 defined between adjacent ones of the flat plates 410. Here, the four intermediate flat plates 413 to 416 will be referred to as, from highest to lowest, a first intermediate flat plate 413, a second intermediate flat plate 414, a third intermediate flat plate 415, and a fourth intermediate flat plate 416.

[0058] Each flat plate 410 is made of, for example, a metal material, such as stainless steel, or a resin material. Each flat plate 410 may alternatively be made of, for example, paper. In this case, paper including a glass fiber, a metal wire, or the like in addition to plant fibers may be used. The flat plate 410 is able to achieve higher dimensional accuracy when the flat plate 410 is made of a metal material than when the flat plate 410 is made of a resin material. Each flat plate 410 has a central hole 65 (see FIG. 4) arranged to pass therethrough in the vertical direction in a center thereof. The shape of each flat plate 410 will be described in detail below.

[0059] Referring to FIG. 4, each spacer 420 is a member in the shape of a circular ring. The spacers 420 are arranged between the flat plates 410 to secure the axial gaps 400 between the flat plates 410. Each spacer 420 has a central hole 429 arranged to pass therethrough in the vertical direction in a center thereof. The motor portion 30 is arranged in the central holes 65 of the flat plates 410 and the central holes 429 of the spacers 420. Each spacer 420 is arranged in a region in the corresponding axial gap 400, the region covering only a portion of the radial extent of the corresponding axial gap 400.

[0060] In this blower apparatus 1, each spacer 420 is made of, for example, a metal or a resin. Note, however, that each spacer 420 may alternatively be defined by a heat-welding sheet. Also note that each spacer 420 may alternatively be defined by at least one metal or resin member and at least one heat-welding sheet placed one upon another.

[0061] Once the motor portion 30 is driven, the air blowing portion 40 is caused to rotate together with the rotating portion 32. As a result, viscous drag of a surface of each flat plate 410 and a centrifugal force together generate an air flow traveling radially outward in the vicinity of the surface of the flat plate 410. Thus, an air flow traveling radially outward is generated in each of the axial gaps 400 between the flat plates 410. Thus, gas above the housing 20 is supplied to each axial gap 400 through the air inlet 202 of the housing 20 and a plurality of air holes 60 of the top flat plate 411 and the intermediate flat plates 413 to 416, and is discharged out of the blower apparatus 1 through the air outlet 201, which is defined in a side portion of the housing 20.

[0062] Here, each flat plate 410 is arranged to have an axial thickness of about 0.1 mm. Meanwhile, each axial gap 400 is arranged to have an axial dimension of about 0.3 mm. The axial dimension of the axial gap 400 is preferably in the range of 0.2 mm to 0.5 mm. An excessively large axial dimension of the axial gap 400 would lead to a separation between an air flow generated by a lower surface of the flat plate 410 on the upper side and an air flow generated by an upper surface of the flat plate 410 on the lower side during rotation of the air blowing portion 40. This separation could result in a failure to generate sufficient static pressure in the axial gap 400 to discharge a sufficient volume of air. Moreover, an excessively large axial dimension of the axial gap 400 would make it difficult to reduce the axial dimension of the blower apparatus 1. Accordingly, in this blower apparatus 1, the axial dimension of the axial gap 400 is arranged to be in the range of 0.2 mm to 0.5 mm. This arrangement allows the blower apparatus 1 to achieve a reduced thickness while allowing an increase in the static pressure in the axial gap 400 to discharge a sufficient volume of air.

[0063] In a related-art blower apparatus that generates air flows by rotating an impeller including a plurality of blades, air flows generated by the impeller leak at upper and lower end portions of the impeller. This leakage of the air flows occurs regardless of the axial dimension of the blower apparatus. Therefore, as the blower apparatus is designed to be thinner, an effect of this leakage on the blower apparatus as a whole becomes greater, resulting in lower air blowing efficiency. Meanwhile, in the blower apparatus 1 according to the present preferred embodiment, the air flows are generated in the vicinity of the surfaces of the flat plates 410, and therefore, the air flows do not easily leak upward or downward. Therefore, even when the axial dimension of the air blowing portion 40, which generates the air flows, is reduced, a reduction in air blowing efficiency due to leakages of the air flows does not easily occur. That is, even when the blower apparatus 1 has a reduced thickness, a reduction in air blowing efficiency thereof does not easily occur.

[0064] In addition, in a blower apparatus including an impeller, periodic noise occurs owing to the shape, number, arrangement, and so on of blades. However, this blower apparatus 1 is superior to a comparable blower apparatus including an impeller in terms of being silent, because the air flows are generated by the viscous drag of the surface of each flat plate 410 and the centrifugal force in the blower apparatus 1.

[0065] In addition, from the viewpoint of P-Q characteristics (i.e., flow rate-static pressure characteristics), the blower apparatus 1 including the flat plates 410 is able to produce a higher static pressure in a low flow rate region than the blower apparatus including the impeller. Therefore, when compared to the blower apparatus including the impeller, the blower apparatus 1 is suitable for use in a densely packed case, from which only a relatively small volume of air can be discharged. Examples of such cases include cases of electronic devices, such as, for example, personal computers.

[0066] Referring to FIG. 2, the air inlet 202 is centered on the central axis 9. That is, a center of the air inlet 202 coincides with the central axis 9. Meanwhile, the air blowing portion 40 is also centered on the central axis 9. Accordingly, differences in pressure do not easily occur at different circumferential positions in the air blowing portion 40. This contributes to reducing noise. It is assumed that the term "coincide" as used here includes not only "completely coincide" but also "substantially coincide".

[0067] 1-2. Shapes of Flat Plates

[0068] Next, the shape of each flat plate 410 will now be described in detail below with reference to FIGS. 6 and 7. FIG. 6 is an exploded perspective view of the flat plates 410. FIG. 7 is a top view of the flat plates 410.

[0069] Referring to FIG. 6, in the present preferred embodiment, each of the top flat plate 411 and the four intermediate flat plates 413 to 416 is arranged to have the same shape and size. Each of the top flat plate 411 and the intermediate flat plates 413 to 416 includes an inner annular portion 61, an outer annular portion 62, a plurality of ribs 63, and the plurality of air holes 60. In the present preferred embodiment, the number of ribs 63 and the number of air holes 60 included in each of the top flat plate 411 and the intermediate flat plates 413 to 416 are both five.

[0070] The inner annular portion 61 is an annular portion centered on the central axis 9. The inner annular portion 61 has the central hole 65 arranged to pass therethrough in the vertical direction in a center thereof. The outer annular portion 62 is an annular portion arranged radially outside of the inner annular portion 61 with the central axis 9 as a center thereof. Each rib 63 is arranged to join the inner annular portion 61 and the outer annular portion 62 to each other. Each air hole 60 is arranged to be in communication with a space radially outside of the air blowing portion 40 through the axial gap(s) 400 adjacent to the flat plate 410 including the air hole 60 on the upper and/or lower sides of the flat plate 410. Each air hole 60 is arranged at a position overlapping with the air inlet 202 of the housing 20 when viewed in the axial direction.

[0071] The bottom flat plate 412 is an annular and plate-shaped member centered on the central axis 9. The bottom flat plate 412 has the central hole 65 arranged to pass therethrough in the vertical direction in a center thereof.

[0072] In the present preferred embodiment, the top flat plate 411 and all the intermediate flat plates 413 to 416 include the air holes 60. Accordingly, all the axial gaps 400 are in axial communication with a space above the housing 20 through the air inlet 202 and the air holes 60. In each of the top flat plate 411 and the intermediate flat plates 413 to 416, the outer annular portion 62, which is arranged radially outside of the air holes 60, defines an air blowing region which generates an air flow in the vicinity of a surface thereof. Meanwhile, the bottom flat plate 412 includes no air hole 60. Therefore, in an upper surface of the bottom flat plate 412, an entire region radially outside of a portion of the bottom flat plate 412 which makes contact with the spacer 420 defines an air blowing region. In other words, in the upper surface of the bottom flat plate 412, a region which axially coincides with the air holes 60 and the ribs 63 of the top flat plate 411 and the intermediate flat plates 413 to 416, and a region which axially coincides with the outer annular portions 62 thereof, together define the air blowing region. In addition, in a lower surface of the bottom flat plate 412, an entire region radially outside of a portion of the bottom flat plate 412 which makes contact with the flat plate holding portion 523 defines an air blowing region. Notice that an air flow is generated by a lower surface of the flat plate holding portion 523 as well.

[0073] Here, the bottom flat plate 412 includes five projecting portions 710 each of which is arranged to project upward. Meanwhile, each of the top flat plate 411 and the intermediate flat plates 413 to 416 includes a positioning hole 720 in each of the ribs 63 thereof. Each positioning hole 720 is a through hole arranged to pass through the rib 63 in the axial direction. One of the projecting portions 710 is fitted in each positioning hole 720. Thus, the bottom flat plate 412 defines a first positioning flat plate 71 including the projecting portions 710 projecting upward. In addition, the top flat plate 411 and the intermediate flat plates 413 to 416 define a plurality of second positioning flat plates 72 arranged upwardly adjacent to the first positioning flat plate 71, each second positioning flat plate 72 including the positioning holes 720.

[0074] Each of the ribs 63 of each of the top flat plate 411 and the intermediate flat plates 413 to 416, which are the second positioning flat plates 72, includes an inner edge portion defining the positioning hole 720, and the inner edge portion defines an opposing portion arranged to be circumferentially opposed to a corresponding one of the projecting portions 710 of the bottom flat plate 412, which is the first positioning fiat plate 71. Notice that the wording "to be opposed to" includes both "to be opposed to an object in a non-contact manner with an intervening gap" and "to be opposed to and in contact with an object without an intervening gap".

[0075] Thus, the bottom flat plate 412, which is the first positioning flat plate 71, and the other flat plates 410, which are the second positioning flat plates 72, include portions circumferentially opposed to each other, and this makes it easier to circumferentially position the flat plates 410 with respect to each other. This enables the flat plates 410 to be positioned with respect to each other quickly and securely. This makes it possible to quickly assemble the air blowing portion 40 in a process of manufacturing the blower apparatus 1.

[0076] In particular, since the projecting portions 710 are inserted into the positioning holes 720, the opposing portions arranged to be opposed to the projecting portions 710 are arranged on both circumferential sides of each projecting portion 710. This contributes to preventing each of the second positioning flat plates 72 from being circumferentially displaced to either side relative to the first positioning flat plate 71. This contributes to more securely arranging the flat plates 410 in desired relative positions.

[0077] In addition, the inner edge portion of each rib 63 which defines the positioning hole 720 is opposed to the corresponding projecting portion 710 in a radial direction as well. This contributes to preventing each second positioning flat plate 72 from being displaced in the radial direction relative to the first positioning flat plate 71. This contributes to more securely arranging the flat plates 410 in desired relative positions.

[0078] In addition, in this blower apparatus 1, each projecting portion 710 is arranged to project upward from the bottom flat plate 412, which is the first positioning flat plate 71. Therefore, in a process of manufacturing the air blowing portion 40, the top flat plate 411 and the intermediate flat plates 413 to 416, which are the second positioning flat plates 72, can be placed above the bottom flat plate 412, which is the first positioning flat plate 71, one after another from bottom to top. Therefore, the air blowing portion 40 can be easily assembled, resulting in improved manufacturing efficiency.

[0079] In this blower apparatus 1, the positioning holes 720 are defined in the ribs 63 as described above. That is, the projecting portions 710 are inserted into the ribs 63, which are arranged radially inward of the outer annular portion 62, which defines the air blowing region. This contributes to preventing each projecting portion 710 from interfering with an air flow traveling radially outward in any axial gap 400. This contributes to preventing each projecting portion 710 from reducing the air blowing efficiency of the blower apparatus 1.

2. EXAMPLE MODIFICATIONS

[0080] While a preferred embodiment of the present invention has been described above, it is to be understood that the present invention is not limited to the above-described preferred embodiment.

[0081] FIG. 8 is a partial sectional view of a blower apparatus 1A according to a modification of the above-described preferred embodiment. FIG. 9 is an exploded perspective view of a plurality of flat plates 410A of the blower apparatus 1A according to the modification illustrated in FIG. 8. In the blower apparatus 1A according to the modification illustrated in FIGS. 8 and 9, an air blowing portion 40A includes the plurality of flat plates 410A, which are arranged in the axial direction with an axial gap 400A defined between adjacent ones of the flat plates 410A, and a plurality of spacers 420A, similarly to the air blowing portion 40 according to the above-described preferred embodiment.

[0082] A bottom flat plate 412A is in the shape of a circular ring, and includes a first central hole 651A, which is a circular through hole. In addition, each of a top flat plate 411A and intermediate flat plates 413A, 414A, 415A, and 416A is in the shape of a circular ring, and includes a second central hole 652A, which is a circular through hole. The second central hole 652A has a larger area than the first central hole 651A in a plan view. As a result, a radial gap between a motor portion 30A and an inner edge portion of each of the top flat plate 411A and the intermediate flat plates 413A to 416A, the inner edge portion defining the second central hole 652A, defines an air hole 60A in the shape of a circular ring and arranged to pass therethrough in the axial direction. Thus, the air hole 60A is arranged to extend all the way around the motor portion 30A, and this leads to improved air intake efficiency of the blower apparatus 1A.

[0083] The bottom flat plate 412A includes five projecting portions 710A each of which is arranged to project upward. Meanwhile, each of the top flat plate 411A and the intermediate flat plates 413A to 416A includes five positioning holes 720A. Each positioning hole 720A is a through hole arranged to pass through a corresponding one of the flat plates 411A and 413A to 415A in the axial direction. One of the projecting portions 710A is fitted in each positioning hole 720A. Thus, the bottom flat plate 412A defines a first positioning flat plate 71A including the projecting portions 710A projecting upward. In addition, the top flat plate 411A and the intermediate flat plates 413A to 416A define a plurality of second positioning flat plates 72A arranged upwardly adjacent to the first positioning flat plate 71A. Each of the top flat plate 411A and the intermediate flat plates 413A to 416A, which are the second positioning flat plates 72A, includes inner edge portions each of which defines a separate one of the positioning holes 720A, and each of the inner edge portions defines an opposing portion arranged to be circumferentially opposed to a corresponding one of the projecting portions 710A of the bottom flat plate 412A, which is the first positioning flat plate 71A.

[0084] As described above, the bottom flat plate 412A, which is the first positioning flat plate 71A, and the other flat plates 410A, which are the second positioning flat plates 72A, include portions circumferentially opposed to each other, and this makes it easier to circumferentially position the flat plates 410A with respect to each other. This enables the flat plates 410A to be positioned with respect to each other quickly and securely. This makes it possible to quickly assemble the air blowing portion 40A in a process of manufacturing the blower apparatus 1A.

[0085] In particular, since the projecting portions 710A are inserted into the positioning holes 720A, the inner edge portions of each second positioning flat plate 72A, the inner edge portions defining the positioning holes 720A thereof, are arranged on both circumferential sides of each projecting portion 710A. That is, each inner edge portion of each second positioning flat plate 72A defines an opposing portion arranged to be circumferentially opposed to a corresponding one of the projecting portions 710A. This contributes to preventing each of the second positioning flat plates 72A from being circumferentially displaced to either side relative to the first positioning flat plate 71A. This contributes to more securely arranging the flat plates 410A in desired relative positions.

[0086] Referring to FIG. 8, the spacers 420A are arranged between adjacent ones of the flat plates 410A, each spacer 420A being arranged in an annular shape around a corresponding one of the projecting portions 710A. This secures the axial gap 400A between the adjacent flat plates 410A.

[0087] In the blower apparatus 1A according to the modification illustrated in FIGS. 8 and 9, each projecting portion 710A is arranged radially outward of the air hole 60A between the motor portion 30A and each of the top flat plate 411A and the intermediate flat plates 413A to 416A. Thus, the positioning of the flat plates 410A is done at a relatively outer position in the radial direction, and this contributes to more precisely arranging the flat plates 410A in desired relative circumferential positions.

[0088] FIG. 10 is a partial sectional view of a blower apparatus 1B according to another modification of the above-described preferred embodiment. In the blower apparatus 1B according to the modification illustrated in FIG. 10, an air blowing portion 40B includes a plurality of flat plates 410B arranged in the axial direction with an axial gap 400B defined between adjacent ones of the flat plates 410B. The flat plates 410B include a top flat plate 411B, which is arranged at the highest position, a bottom flat plate 412B, which is arranged at the lowest position, and four intermediate flat plates 413B, 414B, 415B, and 416B, which are arranged below the top flat plate 411B and above the bottom flat plate 412B. The four intermediate flat plates 413B to 416B will be referred to as, from highest to lowest, a first intermediate flat plate 413B, a second intermediate flat plate 414B, a third intermediate flat plate 415B, and a fourth intermediate flat plate 416B.

[0089] The bottom flat plate 412B is in the shape of a circular ring, and includes a first central hole 651B, which is a circular through hole. In addition, each of the top flat plate 411B and the Intermediate flat plates 413B to 416B is in the shape of a circular ring, and includes a second central hole 652B, which is a circular through hole. The second central hole 652B has a larger area than the first central hole 651B in a plan view. As a result, a radial gap between a motor portion 30B and an inner edge portion of each of the top flat plate 411B and the intermediate flat plates 413B to 416B, the inner edge portion defining the second central hole 652B, defines an air hole 60B in the shape of a circular ring and arranged to pass therethrough in the axial direction. Thus, the air hole 60B is arranged to extend all the way around the motor portion 30B, and this leads to improved air intake efficiency of the blower apparatus 1B.

[0090] The bottom flat plate 412B includes a plurality of projecting portions 710B each of which is arranged to project upward. Meanwhile, each of the top flat plate 411B and the intermediate flat plates 413B to 416B includes positioning holes 720B, each of which is a through hole. One of the projecting portions 710B is fitted in each positioning hole 720B. Thus, the bottom flat plate 412B defines a first positioning flat plate 71B including the projecting portions 710B projecting upward. In addition, the top flat plate 411B and the intermediate flat plates 413B to 416B define a plurality of second positioning flat plates 72B arranged upwardly adjacent to the first positioning flat plate 71B. Each of the top flat plate 411B and the intermediate flat plates 413B to 416B, which are the second positioning flat plates 72B, includes inner edge portions each of which defines a separate one of the positioning holes 720B, and each of the inner edge portions defines an opposing portion arranged to be circumferentially opposed to a corresponding one of the projecting portions 710B of the bottom flat plate 412B, which is the first positioning fiat plate 71B.

[0091] In addition, each projecting portion 710B is arranged to become smaller in a cross-sectional area perpendicular to the axial direction at higher positions. Meanwhile, the top flat plate 411B and the intermediate flat plates 413B to 416B, which are the second positioning flat plates 72B, are arranged to have smaller diameters of the positioning holes 720B as they are arranged at higher positions. Specifically, each positioning hole 720B of the third intermediate flat plate 415B is arranged to be smaller than each positioning hole 720B of the fourth intermediate flat plate 416B. Each positioning hole 720B of the second intermediate flat plate 414B is arranged to be smaller than each positioning hole 720B of the third intermediate flat plate 415B. Each positioning hole 720B of the first intermediate flat plate 413B is arranged to be smaller than each positioning hole 720B of the second intermediate flat plate 414B. Each positioning hole 720B of the top flat plate 411B is arranged to be smaller than each positioning hole 720B of the first intermediate flat plate 413B.

[0092] As described above, the projecting portions 710B and the positioning holes 720B are arranged to become gradually smaller at higher axial positions, and this contributes to preventing each second positioning flat plate 72B from being displaced downward from a predetermined axial position. Thus, the flat plates 410B can be fixed in desired relative axial positions without a spacer being arranged between adjacent ones of the flat plates 410B.

[0093] In addition, the bottom flat plate 412B, which is the first positioning flat plate 71B, and the other flat plates 410B, which are the second positioning flat plates 72B, include portions circumferentially opposed to each other, and this makes it easier to circumferentially position the flat plates 410B with respect to each other. This enables the flat plates 410B to be positioned with respect to each other quickly and securely. This makes it possible to quickly assemble the air blowing portion 40B in a process of manufacturing the blower apparatus 1B.

[0094] FIG. 11 is an exploded perspective view of a plurality of flat plates 410C of a blower apparatus according to yet another modification of the above-described preferred embodiment. In the blower apparatus according to the modification illustrated in FIG. 11, an air blowing portion includes the plurality of flat plates 410C arranged in the axial direction with an axial gap defined between adjacent ones of the flat plates 410C.

[0095] A bottom flat plate 412C is in the shape of a circular ring, and includes a first central hole 651C, which is a circular through hole. In addition, each of a top flat plate 411C and intermediate flat plates 413C, 414C, 415C, and 416C is in the shape of a circular ring, and includes a second central hole 652C, which is a circular through hole. The second central hole 652C has a larger area than the first central hole 651C in a plan view.

[0096] The bottom flat plate 412C includes five projecting portions 710C each of which is arranged to project upward. Meanwhile, each of the top flat plate 411C and the intermediate flat plates 413C to 416C includes five cuts 730C each of which is recessed radially inward from an outer edge thereof. One of the projecting portions 710C is fitted in each cut 730C. Thus, the bottom flat plate 412C defines a first positioning flat plate 71C including the projecting portions 710C projecting upward. In addition, the top flat plate 411C and the intermediate flat plates 413C to 416C define a plurality of second positioning flat plates 72C arranged upwardly adjacent to the first positioning flat plate 71C. Each of the top flat plate 411C and the intermediate flat plates 413C to 416C, which are the second positioning flat plates 72C, includes edge portions each of which defines a separate one of the cuts 730C, and each of the edge portions defines an opposing portion arranged to be circumferentially opposed to one of the projecting portions 710C of the bottom flat plate 412C, which is the first positioning flat plate 71C.

[0097] As described above, in the modification illustrated in FIG. 11, each of the cuts 730C, instead of the positioning holes, defines an opposing portion arranged to be opposed to the corresponding projecting portion 710C. The projecting portions 710C are inserted into the cuts 730C, and thus, the opposing portions arranged to be opposed to the projecting portions 710C can be arranged on both circumferential sides of each projecting portion 710C. This makes it easier to circumferentially position the flat plates 410C with respect to each other.

[0098] FIG. 12 is a partial sectional view of a blower apparatus 1D according to yet another modification of the above-described preferred embodiment. In the blower apparatus 1D according to the modification illustrated in FIG. 12, a motor portion 30D includes a stationary portion 31D, a rotating portion 32D, and two ball bearings 33D.

[0099] The stationary portion 31D includes a stator fixing portion 311D and a stator 312D. The stator fixing portion 311D is a member being cylindrical and having a closed bottom and fixed to a housing 20D. The stator 312D is an armature fixed to an outer circumferential surface of the stator fixing portion 311D.

[0100] The rotating portion 32D includes a shaft 321D, a hub 322D, and a magnet 324D. At least a lower end portion of the shaft 321D is arranged inside of the stator fixing portion 311D. In addition, an upper end portion of the shaft 321D is fixed to the hub 322D. The magnet 324D is fixed to the hub 322D. The magnet 324D is arranged radially opposite to the stator 312D.

[0101] Each ball bearing 33D is arranged to connect the rotating portion 32D to the stationary portion 31D such that the rotating portion 32D is rotatable with respect to the stationary portion 31D. Specifically, an outer race of each ball bearing 33D is fixed to an inner circumferential surface of the stator fixing portion 311D of the stationary portion 31D. In addition, an inner race of each ball bearing 33D is fixed to an outer circumferential surface of the shaft 321D of the rotating portion 32D. Further, a plurality of balls, each of which is a spherical rolling element, are arranged between the outer race and the inner race. As described above, instead of a fluid dynamic bearing, rolling-element bearings, such as, for example, ball bearings, may be used as a bearing structure of the motor portion 30D.

[0102] In the modification illustrated in FIG. 12, the motor portion 30D includes the two ball bearings 33D. The ball bearings 33D are arranged near an upper end and a lower end of an axial range over which the inner circumferential surface of the stator fixing portion 311D and the shaft 321D are opposed to each other. This contributes to preventing the shaft 321D from being inclined with respect to a central axis 9D.

[0103] FIG. 13 is a top view of a blower apparatus 1E according to yet another modification of the above-described preferred embodiment. In the blower apparatus 1E according to the modification illustrated in FIG. 13, a housing 20E includes a plurality of air outlets 201E. Specifically, a side wall portion 22E includes the air outlets 201E, each of which is arranged to face in a radial direction, at a plurality of circumferential positions. The housing 20E includes tongue portions 203E, each of which is arranged near a separate one of the air outlets 201E. In addition, an air blowing portion 40E includes a plurality of flat plates 410E arranged in the axial direction with an axial gap defined between adjacent ones of the flat plates 410E.

[0104] In a centrifugal fan including an impeller, periodic noise occurs owing to the shape, number, arrangement, and so on of blades. In addition, such noise tends to easily occur around a tongue portion. Accordingly, when air is to be discharged in a plurality of directions, a deterioration in noise characteristics occurs because of an increased number of tongue portions. However, in this blower apparatus 1E, air flows traveling radially outward are generated by rotation of the flat plates 410E, and therefore, the blower apparatus 1E is able to achieve reduced periodic noise when compared to the centrifugal fan including the impeller. Therefore, the blower apparatus 1E, which is designed to discharge air in a plurality of directions, does not significantly deteriorate in noise characteristics due to the tongue portions 203E.

[0105] Note that, although the number of flat plates included in the air blowing portion is six in each of the above-described preferred embodiment and the modifications thereof, this is not essential to the present invention. The number of flat plates may alternatively be two, three, four, five, or more than six.

[0106] Also note that, although each of the projecting portions arranged to project from the first positioning flat plate is circumferentially opposed to a portion of a main body of each second positioning flat plate in each of the above-described preferred embodiment and the modifications thereof, this is not essential to the present invention. For example, in another preferred embodiment of the present invention, a projecting portion arranged to project from a first positioning flat plate toward an adjacent second positioning flat plate, and a projecting portion arranged to project from the second positioning flat plate toward the first positioning flat plate, may be circumferentially opposed to each other.

[0107] Also note that, although the bottom flat plate, which is arranged at the lowest position of all the flat plates, defines the first positioning flat plate in each of the above-described preferred embodiment and the modifications thereof, this is not essential to the present invention. In another preferred embodiment of the present invention, a top flat plate arranged at the highest position of all flat plates may define a first positioning flat plate and include a projecting portion arranged to project downward. In yet another preferred embodiment of the present invention, an intermediate flat plate may define a first positioning flat plate and include at least one of a projecting portion arranged to project upward and a projecting portion arranged to project downward.

[0108] Also note that, although only one of the flat plates defines the first positioning flat plate in each of the above-described preferred embodiment and the modifications thereof, this is not essential to the present invention. In another preferred embodiment of the present invention, two or more of a plurality of flat plates may define first positioning flat plates. In this case, one or more flat plates adjacent to each of the first positioning flat plates define a second positioning flat plate(s).

[0109] Also note that, although each of all the flat plates defines the first positioning flat plate or the second positioning flat plate in each of the above-described preferred embodiment and the modifications thereof, this is not essential to the present invention. In another preferred embodiment of the present invention, at least one of a plurality of flat plates may define neither a first positioning flat plate nor a second positioning flat plate.

[0110] Also note that, although the hub is defined by two members, i.e., the hub body member and the flange member, in each of the above-described preferred embodiment and the modifications thereof, this is not essential to the present invention. The hub may alternatively be defined by a single member, or three or more members.

[0111] Also note that the detailed shape of any member may be different from the shape thereof as illustrated in the accompanying drawings of the present application. For example, the shape of any of the housing, the air blowing portion, and the motor portion may be different from that according to each of the above-described preferred embodiment and the modifications thereof. Also note that features of the above-described preferred embodiment and the modifications thereof may be combined appropriately as long as no conflict arises.

[0112] Preferred embodiments of the present invention are applicable to blower apparatuses.

[0113] While preferred embodiments of the present invention 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 invention. The scope of the present invention, therefore, is to be determined solely by the following claims.

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