JP2017219036A - Blower device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce thickness of a blower device used for cooling electronic equipment, as reduction in size and thickness of the electronic equipment is required.SOLUTION: A housing includes: an intake port penetrating in an axial direction at an upper part of a blower part; and an air blowing port opening toward the radial direction radially outside of the blower part. At least one part of flat plates 410 is an imperfectly round flat plate having an outer edge shape in which a specific shape appears repeatedly in the circumferential direction in a plan view. When the blower part rotates, by viscosity resistance of the surface of the flat plate 410 and a centrifugal force, an airflow going radially outside generates between the flat plates. As the airflow generates between the flat plates, the airflow hardly leaks in the vertical direction, and air blowing efficiency can be improved. Therefore, even in the case where thickness is reduced, air blowing efficiency hardly deteriorates. By the flat plate 410 being an imperfectly round flat plate, a whirl of a small airflow is intentionally generated in the vicinity of an outer edge part of the flat plate 410, and further quietness can be achieved.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a blower.

  2. Description of the Related Art Conventionally, there is known a centrifugal blower that generates an air flow outward in the radial direction by rotating an impeller having a plurality of blades. About the conventional air blower which has an impeller, it describes in Unexamined-Japanese-Patent No. 2008-88985, for example.

In the blower described in Japanese Patent Application Laid-Open No. 2008-88985, a plurality of blades called fan blades push out surrounding gas, thereby generating an air flow that goes radially outward.
JP 2008-88985 A

  In recent years, there has been a continuing demand for smaller and thinner electronic devices. For this reason, thickness reduction is calculated | required also about the air blower used for the cooling in an electronic device.

  Here, when an airflow is generated using an impeller as in the blower described in Japanese Patent Application Laid-Open No. 2008-88985, the airflow pushed out by the blades leaks from the upper and lower ends in the axial direction of the blades during rotation. As a result, the wind pressure at the upper and lower ends in the axial direction of the blade is smaller than the wind pressure near the axial center of the blade. For this reason, if the delivery device is thinned and the length of the impeller in the axial direction becomes small, there arises a problem that sufficient blowing efficiency cannot be obtained.

  In addition, air blowers mounted in electronic devices and the like are required to be quiet in addition to being thin.

  The objective of this invention is providing the technique which can implement | achieve the noise reduction of the centrifugal air blower with favorable ventilation efficiency.

  An exemplary first invention of the present application includes a blower that rotates around a central axis extending in the vertical direction, a motor that rotates the blower, and a housing that houses the blower and the motor. . The housing is disposed at an upper portion of the air blowing portion, and has an air inlet that penetrates in the axial direction. Have. The air blower includes a plurality of flat plates arranged in the axial direction with an axial gap therebetween. At least some of the plurality of flat plates are non-circular flat plates having an outer edge shape in which a specific shape repeatedly appears in the circumferential direction in plan view.

  According to the exemplary first invention of the present application, when the air blowing section rotates, an air flow toward the radially outer side is generated in the axial gap between the flat plates due to the viscous resistance and centrifugal force of the flat plate surfaces. Thereby, the gas supplied via the inlet port and the vent hole is directed outward in the radial direction of the blower. Since the airflow is generated between the flat plates, the airflow is less likely to leak in the vertical direction, and the air blowing efficiency can be improved. Therefore, even if it is a case where it thins, ventilation efficiency does not fall easily. Moreover, it is excellent in silence compared with a centrifugal fan having an impeller. Since the flat plate is a non-circular flat plate, a small air vortex is intentionally generated in the vicinity of the outer edge of the flat plate, thereby further reducing the noise.

FIG. 1 is a perspective view of the blower according to the first embodiment. FIG. 2 is a top view of the air blower according to the first embodiment. FIG. 3 is a cross-sectional view of the blower according to the first embodiment. FIG. 4 is an exploded perspective view of the air blower according to the first embodiment. FIG. 5 is a partial cross-sectional view of the blower according to the first embodiment. FIG. 6 is a top view of a plurality of flat plates of the blower according to the first embodiment. FIG. 7 is a top view of a plurality of flat plates of a blower according to a modification. FIG. 8 is a partial cross-sectional view of a blower according to a modification. FIG. 9 is a top view of a blower according to a modification.

  Below, the example of an air blower is disclosed. In the present disclosure, the shape and positional relationship of each part will be described with the upper plate part facing up with respect to the lower plate part. However, there is no intention to limit the direction at the time of manufacture and use of the blower by the definition of the vertical direction.

<1. First Embodiment>
<1-1. Configuration of blower>
FIG. 1 is a perspective view of the blower 1 according to the first embodiment. FIG. 2 is a top view of the blower 1. FIG. 3 is a cross-sectional view of the blower device 1 in the AA cross section. FIG. 4 is an exploded perspective view of the blower 1. FIG. 5 is a partial cross-sectional view of the blower device 1. The blower 1 is a centrifugal blower that generates an airflow toward the radially outer side when the blower 40 rotates. For example, the blower 1 is mounted on an electronic device such as a personal computer and used to cool the inside thereof. In addition, the air blower of the present invention may be used for other purposes.

  As shown in FIGS. 1 to 4, the blower device 1 includes a housing 20, a motor unit 30, and a blower unit 40.

  The housing 20 is a housing that houses the motor unit 30 and the air blowing unit 40. The housing 20 includes a lower plate portion 21, a side wall portion 22, and an upper plate portion 23.

  The lower plate portion 21 constitutes the bottom portion of the housing 20. The lower plate portion 21 extends in the radial direction below the blower portion 40 and covers at least a part of the lower side of the blower portion 40. Further, the lower plate portion 21 supports the motor portion 30.

  The side wall portion 22 extends upward from the lower plate portion 21. The side wall part 22 covers the side of the air blowing part 40 between the lower plate part 21 and the upper plate part 23. Moreover, the side wall part 22 has the ventilation port 201 opened toward radial direction in a part of circumferential direction. In the present embodiment, the lower plate portion 21 and the side wall portion 22 are integrally formed. However, the lower plate portion 21 and the side wall portion 22 may be separate members.

  The upper plate portion 23 constitutes a lid portion of the housing 20. The upper plate portion 23 extends in the radial direction above the lower plate portion 21. Further, the upper plate portion 23 has an intake port 202 penetrating in the axial direction. That is, the upper plate portion 23 has an inner edge portion 231 that constitutes the air inlet 202. The shape of the air inlet 202 in the top view is, for example, a circle centered on the central axis 9.

  The motor unit 30 is a drive unit that rotates the blower unit 40. As shown in FIG. 5, the motor unit 30 includes a stationary unit 31 and a rotating unit 32. The stationary part 31 is fixed to the lower plate part 21. Thereby, the stationary part 31 is relatively stationary with respect to the housing 20. The rotating portion 32 is supported so as to be rotatable about the central axis 9 with respect to the stationary portion 31.

  The stationary part 31 includes a stator fixing part 311, a stator 312, and a bearing housing 313.

  The stator fixing portion 311 is fitted into a fixing hole 211 provided 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 extends in a cylindrical shape about the central axis 9 from the fixing portion with the fixing hole 211 upward. A stator 312 is fixed to the outer periphery of the upper portion of the stator fixing portion 311.

  The stator 312 is an armature that generates a magnetic flux according to a drive current supplied from the outside. The stator 312 annularly surrounds the central axis 9 extending vertically. The stator 312 has, for example, an annular stator core made of laminated steel plates and a conductive wire wound around the stator core.

  The bearing housing 313 is a bottomed cylindrical member. That is, the bearing housing 313 has a disk-shaped bottom portion and a cylindrical portion extending upward from the bottom portion. The bearing housing 313 is fixed to the inner peripheral surface of the stator fixing portion 311.

  The rotating unit 32 includes a shaft 321, a hub 322, a bearing member 323, and a magnet 324.

  The shaft 321 is a member disposed along the central axis 9. The shaft 321 according to the present embodiment is disposed inside a first cylindrical portion 512, which will be described later, and has a columnar portion extending around the central axis 9, and a circle extending in the radial direction from the lower end portion of the columnar portion. A plate-like portion.

  The hub 322 is fixed to the shaft 321. The hub 322 includes a hub body member 51 and a flange member 52.

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

  The first top plate portion 511 is a disk-shaped portion that extends in the radial direction about the central axis 9. The first top plate portion 511 is disposed above the stator 312. The 1st top plate part 511 has the recessed part 515 dented from an upper surface in the outer edge part.

  The first cylindrical portion 512 extends in a cylindrical shape about the central axis 9 from the first top plate portion 511 downward. A cylindrical portion of the shaft 321 is accommodated in the first cylindrical portion 512. The shaft 321 is fixed to the first cylindrical portion 512.

  The second cylindrical portion 513 extends in a cylindrical shape about the central axis 9 from the first top plate portion 511 downward. The inner diameter of the second cylindrical portion 513 is larger than the outer diameter of the first cylindrical portion 512. That is, the second cylindrical portion 513 is disposed on the radially outer side of the first cylindrical portion 512.

  The magnet holding part 514 extends in a cylindrical shape centering on the central axis 9 from the radial outer end of the first top plate part 511 downward. The magnet holding part 514 is disposed on the radially outer side of the stator 312. A magnet 324 is fixed to the inner peripheral surface of the magnet holding portion 514.

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

  The outer wall portion 521 is a cylindrical portion that extends vertically around the central axis 9. The outer wall portion 521 is disposed along the outer peripheral surface of the magnet holding portion 514 of the hub body member 51.

  The second top plate portion 522 extends in an annular shape from the upper end portion of the outer wall portion 521 radially inward. The second top plate portion 522 is disposed in a recess 515 provided on the upper surface of the first top plate portion 511 of the hub body member 51. Further, the upper surface of the first top plate portion 511 and the upper surface of the second top plate portion 522 have the same axial position.

  The flat plate holding part 523 extends radially outward from the lower end part of the outer wall part 521. The flat plate holding portion 523 holds the blower portion 40 on the radially outer side of the magnet holding portion 514 of the hub body member. In the present embodiment, the air blowing unit 40 is placed on the upper surface of the flat plate holding unit 523. Thereby, the flat plate holding unit 523 holds the plurality of flat plates 410 of the blower unit 40.

  The bearing member 323 is a cylindrical member that extends vertically around the central axis 9. The bearing member 323 is disposed along the outer peripheral surface of the first cylindrical portion 512 of the hub body member 51. The bearing member 323 is fixed to the outer peripheral surface of the first cylindrical portion 512. A cylindrical portion of the bearing housing 313 is disposed on the radially outer side of the bearing member 323 and on the radially inner side of the second cylindrical portion 513 of the hub body member 51.

  The magnet 324 is fixed to the inner peripheral surface of the magnet holding part 514 of the hub body member 51. Further, the magnet 324 is disposed on the radially outer side of the stator 312. In the present embodiment, an annular magnet 324 is used. The radially inner surface of the magnet 324 faces the stator 312 in the radial direction with a slight gap. In addition, N poles and S poles are alternately magnetized in the circumferential direction on the inner peripheral surface of the magnet 324. Instead of the annular magnet 324, a plurality of magnets may be used. When a plurality of magnets are used, the plurality of magnets may be arranged in the circumferential direction so that N-pole magnets and S-pole magnets are alternately arranged.

  As shown enlarged in FIG. 5, the lubricating fluid 300 is interposed between the bearing housing 313 and the shaft 321, the bearing member 323, and the hub body member 51. For the lubricating fluid 300, for example, polyol ester oil or diester oil is used. The shaft 321, the hub 322, and the bearing member 323 are rotatably supported by the bearing housing 313 via the lubricating fluid 300. As described above, in this embodiment, the bearing housing 313 that is a component of the stationary portion 31, the shaft 321 that is the component of the rotating portion 32, the bearing member 323, the hub body member 51, and the lubricating fluid 300, A hydrodynamic bearing is constructed.

  The interface of the lubricating fluid 300 is disposed in a seal portion 301 that is a gap between the outer peripheral surface of the bearing housing 313 and the inner peripheral surface of the second cylindrical portion 513 of the hub body member 51. In the seal portion 301, the distance between the outer peripheral surface of the bearing housing 313 and the inner peripheral surface of the second cylindrical portion 513 increases from the top toward the bottom. That is, in the seal portion 301, the distance between the outer peripheral surface of the bearing housing 313 and the inner peripheral surface of the second cylindrical portion 513 increases as the distance from the interface of the lubricating fluid 300 increases. Thus, the lubricating fluid 300 is attracted upward in the vicinity of the interface by increasing the radial width of the seal portion 301 from the upper side to the lower side. Therefore, leakage of the lubricating fluid 300 to the outside of the seal portion 301 is suppressed.

  Thus, by using a fluid dynamic pressure bearing as a bearing mechanism that connects the stationary part 31 and the rotating part 32, the rotating part 32 can rotate stably. Therefore, the generation of abnormal noise from the motor unit 30 can be suppressed.

  In such a motor unit 30, when a drive current is supplied to the stator 312, magnetic flux is generated in the stator 312. A circumferential torque is generated between the stationary part 31 and the rotating part 32 by the action of the magnetic flux between the stator 312 and the magnet 324. As a result, the rotating part 32 rotates around the central axis 9 with respect to the stationary part 31. The air blowing unit 40 held by the flat plate holding unit 523 of the rotating unit 32 rotates around the central axis 9 together with the rotating unit 32.

  As shown in FIGS. 4 and 5, the air blower 40 includes a plurality of flat plates 410 and a plurality of spacers 420. The flat plate 410 and the spacer 420 are alternately arranged in the axial direction. Adjacent flat plate 410 and spacer 420 are fixed by adhesion or the like.

  As shown in FIGS. 4 and 5, in the present embodiment, the plurality of flat plates 410 include an upper flat plate 411 disposed at the uppermost position, a lower flat plate 412 disposed at the lowermost position, and a lower portion of the upper flat plate 411 and And four intermediate flat plates 413 disposed above the lower flat plate 412. That is, the air blowing unit 40 of the present embodiment has six flat plates 410. The plurality of flat plates 410 are arranged in the axial direction via the axial gap 400.

  Each flat plate 410 is formed of a metal material such as stainless steel or a resin material, for example. Each flat plate 410 may be formed of paper, for example. In that case, paper including glass fiber or metal wire as plant fiber may be used. When the flat plate 410 is formed of a metal material, the dimensional accuracy of the flat plate 410 can be improved as compared with the case where the flat plate 410 is formed of a resin material.

  In the present embodiment, the upper flat plate 411 and the four intermediate flat plates 413 have the same shape. As shown in FIGS. 1, 2, and 5, the upper flat plate 411 and the intermediate flat plate 413 each have an inner annular portion 61, an outer annular portion 62, a plurality of ribs 63, and a plurality of ventilation holes 60. In the present embodiment, each flat plate 410 has five ribs 63 and five air holes 60. Each of the air holes 60 communicates with a space outside the air blower 40 in the radial direction via an axial gap 400 adjacent to the upper and lower sides of the flat plate 410 having the air holes 60. Note that each of the vent holes 60 is disposed at a position overlapping the air inlet 202 of the housing 20 when viewed in the axial direction.

  The lower flat plate 412 is an annular and plate-like member disposed around the central axis 9. The lower flat plate 412 has a central hole 65 penetrating vertically in the center thereof. The details of the shape of each flat plate 410 will be described later.

  As shown in FIG. 4, each of the spacers 420 is an annular member. By arranging the spacer 420 between the flat plates 410, the axial gap 400 is secured between the flat plates 410. Each of the spacers 420 has a central hole 429 penetrating vertically in the center thereof. The motor unit 30 is disposed inside a center hole 65 (described later) of each flat plate 410 and a center hole 429 of each spacer 420.

  The spacer 420 is disposed at a position overlapping the inner annular portion 61 of the upper flat plate 411 and the intermediate flat plate 413 in the axial direction. As described above, the spacer 420 is disposed only in a partial region in the radial direction in the axial gap 400.

  When the motor unit 30 is driven, the air blowing unit 40 is rotated together with the rotating unit 32. As a result, an air flow toward the radially outer side is generated near the surface of each flat plate 410 due to the viscous resistance and centrifugal force on the surface of each flat plate 410. Therefore, an airflow is generated in the axial gap 400 between the flat plates 410 toward the radially outer side. Then, the gas at the top of the housing 20 is supplied to the axial gaps 400 via the air inlets 202 of the housing 20 and the vent holes 60 of the upper flat plate 411 and the intermediate flat plate 413, and is provided on the side of the housing 20. The blower outlet 201 is discharged outside the blower 1.

  Here, the axial thickness of each flat plate 410 is about 0.1 mm. On the other hand, the axial length of each axial gap 400 is about 0.3 mm. The axial length of the axial gap 400 is preferably 0.2 mm to 0.5 mm. When the axial length of the axial gap 400 is large, there is a gap between the airflow generated on the lower surface of the upper flat plate 410 and the airflow generated on the upper surface of the lower flat plate 410 when the blower 40 rotates. Then, the static pressure in the axial gap 400 does not increase, and there is a possibility that a sufficient air volume cannot be discharged. Moreover, when the axial length of the axial gap 400 is large, it is difficult to reduce the size of the blower 1 in the axial direction. For this reason, in the blower 1, the axial length of the axial gap 400 is in the range of 0.2 mm to 0.5 mm. Thereby, the static pressure in the axial gap 400 can be increased, a sufficient exhaust air volume can be obtained, and the blower 1 can be made thinner.

  In addition, as shown in FIG. 2, the intake port 202 is disposed around the central axis 9. That is, the center of the air inlet 202 coincides with the central axis 9. On the other hand, the air blower 40 is also arranged around the central axis 9. Thereby, in the ventilation part 40, it is hard to produce a pressure difference in the circumferential direction. As a result, noise generation can be suppressed. Note that “matching” includes not only the case of complete matching but also the case of approximately matching.

<1-2. Flat plate shape>
Next, the shape of each flat plate 410 will be described in detail with reference to FIGS. 4 and 6. FIG. 6 is a top view of the plurality of flat plates 410.

  In the present embodiment, as shown in FIG. 4, the upper flat plate 411 and the four intermediate flat plates 413 have the same shape. As described above, the upper flat plate 411 and the intermediate flat plate 413 each have the inner annular portion 61, the outer annular portion 62, the plurality of ribs 63, and the plurality of ventilation holes 60.

  The inner annular portion 61 is an annular portion that is arranged around the central axis 9. The inner annular portion 61 has a central hole 65 penetrating vertically in the center thereof. The outer annular portion 62 is an annular portion that is disposed radially outside the inner annular portion 61 about the central axis 9. Each of the ribs 63 connects the inner annular portion 61 and the outer annular portion 62. The vent hole 60 penetrates the flat plate 410 in the axial direction. The vent hole 60 is surrounded by the inner annular portion 61, the outer annular portion 62, and two ribs 63 adjacent in the circumferential direction.

  In a conventional blower that generates an airflow by rotating an impeller having a plurality of blades, the airflow generated by the impeller leaks at the upper and lower ends of the impeller. Moreover, the airflow leakage occurs regardless of the axial length of the blower. For this reason, since the influence of the said leakage in the whole air blower will become large if a thin air blower is made, air blowing efficiency falls. On the other hand, in the blower device 1 of the present embodiment, an air flow is generated near the surface of the flat plate 410, and thus the air flow is difficult to leak in the vertical direction. Therefore, even if the axial length of the blower 40 that generates the airflow is reduced, the blowing efficiency is less likely to decrease due to the leakage of the airflow. That is, even if it is a case where the air blower 1 is made thin, ventilation efficiency does not fall easily.

  Further, in a blower having an impeller, periodic noise is generated due to the shape, number, arrangement, etc. of blades. However, since this air blower 1 generates an air flow by the viscous resistance and centrifugal force on the surface of the flat plate 410, it is more silent than the air blower having an impeller.

  In terms of PQ characteristics (air volume-static pressure characteristics), the air blower 1 having the plurality of flat plates 410 has a larger static pressure in the low air volume region than the air blower having the impeller. For this reason, the blower 1 is suitable for use in a high-density housing that can discharge only a relatively low air volume, compared to a blower having an impeller. Examples of such a case include an electronic device such as a personal computer.

  In the present embodiment, the upper flat plate 411 and all the intermediate flat plates 413 have the air holes 60. As a result, all the axial gaps 400 communicate with the space above the housing 20 in the axial direction via the intake port 202 and the vent hole 60.

  The upper flat plate 411 and the intermediate flat plate 413 have a vent hole 60. For this reason, in the upper flat plate 411 and the intermediate flat plate 413, the outer annular portion 62 disposed outside the vent hole 60 serves as a blowing region that generates an air flow near the surface. On the other hand, the lower flat plate 412 does not have the vent hole 60. For this reason, on the upper surface side of the lower flat plate 412, the entire region outside the portion in contact with the spacer 420 becomes the air blowing region. That is, on the upper surface side of the lower flat plate 412, the region overlapping the vent hole 60 and the rib 63 of the upper flat plate 411 and the intermediate flat plate 413 in the axial direction and the region overlapping the outer annular portion 62 in the axial direction serve as the air blowing region. . Further, on the lower surface side of the lower flat plate 412, the entire region outside the portion in contact with the flat plate holding portion 523 becomes the air blowing region. Airflow is also generated on the lower surface of the flat plate holding portion 523.

  As described above, the air blowing area of the lower flat plate 412 is wider than the air blowing areas of the upper flat plate 411 and the intermediate flat plate 413. Therefore, the static pressure can be improved in the axial gap 400 between the intermediate flat plate 413 and the lower flat plate 412 arranged on the lowermost side as compared with the other axial gaps 400.

  Airflow passing downward through the air inlet 202 and the plurality of vent holes 60 is attracted radially outward in each axial gap 400. For this reason, the airflow passing through the vent hole 60 becomes weaker as it goes downward. In the present embodiment, by making the air blowing area in the lower flat plate 412 larger than the air blowing areas of the upper flat plate 411 and the intermediate flat plate 413, the axial gap 400 arranged at the lowest position is more than the other axial gaps 400. A strong air flow is generated, and the air flow passing downward through the vent hole 60 is attracted. Thereby, a sufficient amount of gas is also supplied to the axial gap 400 arranged at the lowermost position. As a result, the blowing efficiency in the blowing unit 40 is further improved.

  As shown in FIG. 6, each of the plurality of flat plates 410 is a non-circular flat plate having an outer edge shape in which the specific shape 71 appears repeatedly in the circumferential direction in plan view. Here, a shape different from the arcuate curve centered on the central axis 9 is referred to as a “specific shape”. Further, “a specific shape repeatedly appears” means that the outer edge shape includes three or more specific shapes. As described above, since at least a part of the plurality of flat plates 410 has the specific shape 71, a small air vortex is intentionally generated near the outer edge of the flat plate 410. Thereby, generation | occurrence | production of the big vortex | eddy_current can be suppressed. As a result, the generation of noise due to the vortex of the airflow can be suppressed. Therefore, the air blower 1 can be made more silent.

  In this air blower 1, each flat plate 410 has a regular 13-sided outer edge. That is, each flat plate 410 that is a non-circular flat plate has a polygonal outer edge. For this reason, the specific shape 71 includes a linear portion 711 and a corner portion 712. Since the flat plate 410 is a polygon, the specific shape is a simple straight line combination. Therefore, compared with the case where the specific shape is notched, a complicated curved shape, or a shape other than a straight shape such as a combination of a plurality of shapes, noise reduction can be performed without performing a complicated molding process. Can do. Further, the area of the regular triangle is about 96% of the area of the circle having the same outermost diameter. Therefore, the flat plate 410 whose outer edge shape is a regular 13-sided shape can reduce noise without reducing the area of the air blowing region so much as compared to a flat plate whose outer edge shape is the same circle having the same outermost diameter.

  In each flat plate 410, the plurality of specific shapes 71 are arranged at equal intervals in the circumferential direction. The “equal intervals” include “substantially equal intervals”. Since the specific shape 71 is periodically arranged, the weight balance of the flat plate 410 is good. Therefore, the flat plate 410 can rotate stably. As a result, noise can be further reduced.

  Each flat plate 410 has 13 specific shapes 71, which is a prime number. Depending on the number of the specific shapes 71, a noise peak occurs at a frequency corresponding to the natural frequency. When the number of the specific shapes 71 is not a prime number, noise peaks occur at frequencies corresponding to all the divisors. In this air blower 1, since the number of the specific shapes 71 is a prime number, a peak is generated only at a frequency corresponding to the number, so that the number of generated peaks can be reduced. That is, noise can be further reduced. The number of the specific shapes 71 included in each flat plate 410 may be another prime number such as 5, 7, or 11, for example.

  In the blower 1, a 12-pole 9-slot motor is used for the motor unit 30. For this reason, the number of the specific shapes 71 that each flat plate 410 has is relatively prime to the number of slots and the number of poles of the motor unit 30. In the blower 1, the ribs 63 included in the upper flat plate 411 and the intermediate flat plate 413 are five. Therefore, the number of the specific shapes 71 that each flat plate 410 has is relatively prime with the rib 63. Thereby, it is suppressed that the noise generated due to the specific shape 71 resonates with the noise generated due to the motor unit 30 and the rib 63. Therefore, noise can be further reduced.

<2. Modification>
As mentioned above, although exemplary embodiment of this invention was described, this invention is not limited to said embodiment.

  FIG. 7 is a top view of a plurality of flat plates 410A of an air blower according to a modification. In the blower of the example of FIG. 7, each of the plurality of flat plates 410A is a non-circular flat plate having an outer edge shape in which the specific shape 71A repeatedly appears in the circumferential direction in plan view. The specific shape 71A includes a notch 713A that is recessed inward in the radial direction. It is known that by providing serrated irregularities called serrations on a rotating body or a high-speed propulsion body, a collision airflow is diffused and noise is reduced. In this flat plate 410A, the noises in the blower can be reduced by the plurality of notches 713A serving as serrations.

  Moreover, in the air blower of the example of FIG. 7, several flat plate 410A rotates to the circumferential direction one side with rotation of 30 A of motor parts. The outer edge shape of the flat plate 410A constituting the notch 713A includes a notch guide portion 714A that curves toward the other side in the circumferential direction as it goes radially outward. Thereby, the notch guide part 714A follows the direction of the airflow flowing near the surface of the flat plate 410A. For this reason, it is suppressed that the surrounding airflow is prevented in the periphery of the notch guide part 714A. Therefore, the blowing efficiency of the blower 1 is improved.

  As shown in FIG. 7, each of the ribs 63A is curved and extends toward the other side in the circumferential direction as it goes outward in the radial direction. Thereby, the rib 63A follows the direction of the airflow flowing near the surface of the flat plate 410A. For this reason, the rib 63A is unlikely to obstruct the airflow around the flat plate 410A. Therefore, the blowing efficiency of the blower 1 is improved. Moreover, the curvature of the notch guide part 714A and the curvature of the rib 63A are the same. Note that “same” includes “substantially identical”. Thereby, it can suppress more that ventilation efficiency falls resulting from the notch 713A and the rib 63A.

  FIG. 8 is a partial cross-sectional view of an air blower 1B according to another modification. In the blower 1B in the example of FIG. 8, the motor unit 30B includes a stationary unit 31B, a rotating unit 32B, and two ball bearings 33B.

  The stationary part 31B includes a stator fixing part 311B and a stator 312B. The stator fixing portion 311B is a bottomed cylindrical member fixed to the housing 20B. The stator 312B is an armature that is fixed to the outer peripheral surface of the stator fixing portion 311B.

  The rotating part 32B includes a shaft 321B, a hub 322B, and a magnet 324B. The shaft 321B has at least a lower end portion disposed inside the stator fixing portion 311B. The upper end portion of the shaft 321B is fixed to the hub 322B. The magnet 324B is fixed to the hub 322B. The magnet 324B is disposed to face the stator 312B in the radial direction.

  Each of the ball bearings 33B connects the rotating part 32B to the stationary part 31B so as to be rotatable. Specifically, the outer ring of the ball bearing 33B is fixed to the inner peripheral surface of the stator fixing portion 311B of the stationary portion 31B. Further, the inner ring of the ball bearing 33B is fixed to the outer peripheral surface of the shaft 321B of the rotating part 32B. And the ball | bowl which is a some spherical rolling element exists between an outer ring | wheel and an inner ring | wheel. Thus, instead of the fluid dynamic pressure bearing, a rolling bearing (bearing) such as a ball bearing may be used as the bearing structure of the motor unit 30B.

  In the example of FIG. 8, the motor unit 30B has two ball bearings 33B. Then, ball bearings 33B are arranged in the vicinity of the upper end and the lower end of the axial region where the inner peripheral surface of the stator fixing portion 311B and the shaft 321B face each other. Thereby, it is suppressed that the shaft 321B inclines with respect to the central axis 9B.

  FIG. 9 is a top view of a blower 1C according to another modification. In the air blowing device 1C of the example of FIG. 9, the housing 20C has a plurality of air blowing ports 201C. Specifically, the side wall portion 22 </ b> C has air blowing ports 201 </ b> C that open in the radial direction at a plurality of locations in the circumferential direction. The housing 20C has a tongue portion 203C around each air outlet 201C. In addition, the air blower 40C includes a plurality of flat plates 410C arranged in the axial direction with an axial gap therebetween.

  In a centrifugal fan having an impeller, periodic noise is generated due to the shape, number, and arrangement of blades. In addition, the noise is likely to be generated around the tongue. For this reason, when exhausting in a plurality of directions, the number of tongues increases, and noise characteristics are further deteriorated. However, in this blower 1C, since the air flow toward the radially outer side is generated by the rotation of the flat plate 410C, periodic noise can be reduced as compared with the centrifugal fan having the impeller. Therefore, even when exhaust is performed in a plurality of directions as in the air blower 1C, it is possible to suppress deterioration of noise characteristics due to the relationship with the tongue 203C.

  In said embodiment and modification, although the number of the flat plates which a ventilation part has was six, this invention is not limited to this. The number of flat plates may be 2 to 5, or 7 or more.

  Moreover, in said embodiment and modification, although the hub was comprised from two members, a hub main body member and a flange member, this invention is not limited to this. The hub may be composed of one member or may be composed of three or more members.

  Moreover, about the detailed shape of each member, you may differ from the shape shown by each figure of this application. For example, the shape of a housing, a ventilation part, or a motor part may differ from said embodiment and a modification. Moreover, you may combine each said element suitably in the range by which a contradiction does not arise.

  The present invention can be used for a blower.

1, 1B, 1C Blower 9, 9B Center shaft 20, 20B, 20C Housing 30, 30A, 30B Motor part 31, 31B Stationary part 32, 32B Rotating part 33B Ball bearing 40, 40C Air blower 60 Ventilation hole 61 Inner annular part 62 Outer ring portion 63, 63A Rib 71, 71A Specific shape 201, 201C Blower port 202 Inlet port 203C Tongue portion 300 Lubricating fluid 301 Seal portion 312, 312B Stator 313 Bearing housing 321, 321B Shaft 323 Bearing member 324, 324B Magnet 400 Shaft Directional gaps 410, 410A, 410C Flat plate 711 Linear part 712 Corner part 713A Notch 714A Notch guide part

Claims (11)

A blower,
A blower that rotates about a central axis extending in the vertical direction;
A motor unit for rotating the air blowing unit;
A housing that houses the blower section and the motor section;
Have
The housing is
An air intake port disposed in an upper portion of the air blowing portion and penetrating in the axial direction;
An air outlet that is arranged on the radially outer side of the air blowing part and opens in the radial direction at least in a circumferential direction; and
Have
The air blowing part has a plurality of flat plates arranged in the axial direction through an axial gap,
At least a part of the plurality of flat plates is a non-circular flat plate having an outer edge shape in which a specific shape repeatedly appears in a circumferential direction in a plan view. It is an air blower of Claim 1, Comprising:
The said specific shape is a ventilation apparatus containing the notch dented to radial inside. The blower device according to claim 2,
The air blowing part is rotated to one side in the circumferential direction by the motor part,
The blower device including a notch guide portion in which the outer edge shape constituting the notch is curved toward the other side in the circumferential direction toward the radially outer side. It is an air blower of Claim 3, Comprising:
The non-circular flat plates are respectively
An annular inner annular portion disposed around the central axis;
An annular outer annular portion disposed radially outside the inner annular portion around the central axis;
A plurality of ribs connecting the inner annular portion and the outer annular portion in a radial direction;
A plurality of vent holes surrounded by the inner annular portion, the outer annular portion and two ribs adjacent in the circumferential direction and penetrating in the axial direction;
Have
Each of the vent holes communicates with the space on the radially outer side of the air blowing portion via the axial gap,
Each of the ribs curves to the other side in the circumferential direction as it goes radially outward,
The air blower in which the curvature of the notch guide portion and the curvature of the rib are the same. It is an air blower of Claim 1, Comprising:
The specific shape includes a corner,
The non-circular flat plate has a polygonal outer edge. It is an air blower in any one of Claim 1 thru | or 5, Comprising:
The blower device, wherein the number of the specific shape of the non-circular flat plate is a prime number. The blower device according to any one of claims 1 to 6,
In the non-circular flat plate, the plurality of specific shapes are arranged at equal intervals in the circumferential direction. The blower device according to any one of claims 1 to 7,
The air blower in which the center of the air inlet coincides with the central axis. A blower device according to any one of claims 1 to 8,
The motor part is
A stationary part having an armature and a bearing housing;
A rotating part having a magnet, a shaft, and a bearing member, which are arranged at positions opposed to the radial direction of the armature;
Have
A lubricating fluid is interposed between the bearing housing, the shaft and the bearing member,
The interface of the lubricating fluid is disposed in a seal portion that is a gap between the bearing housing and the rotating portion,
The air blower in which the distance between the bearing housing and the rotating part increases as the seal part moves away from the interface. A blower device according to any one of claims 1 to 8,
The motor part is
A stationary part having an armature;
A rotating part having a magnet disposed at a position facing the radial direction of the armature;
A ball bearing that rotatably connects the rotating part to the stationary part;
A blower. A blower device according to any one of claims 1 to 10,
The said housing is an air blower which has the said air outlet in the multiple places of the circumferential direction.

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