Air supply device and blower

Abstract

The blower device is provided with: an impeller; a motor that rotates the impeller; and a housing that houses the impeller and the motor, the motor having a rotor and a stator, the rotor having: a shaft; and a rotor magnet fixed to a radially outer surface of the shaft, the impeller being fixed to a position above a fixing position of the rotor magnet in the radially outer surface of the shaft, the housing having: a first bearing that rotatably supports the shaft at a position above the fixing position of the rotor magnet and below the fixing position of the impeller; and a second bearing that rotatably supports the shaft at a position below the fixed position of the rotor magnet, and the center-of-gravity position of the impeller is either a position overlapping the upper end of the first bearing when viewed from the radial direction or a position below the upper end of the first bearing.

Description

Technical Field

[0001] The invention relates to an air supply device and a hair dryer. Background Art

[0002] A conventional air supply device includes an impeller. The impeller is fixed to a shaft. The impeller rotates together with the shaft (see, for example, Patent Document 1). Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Publication No. 2020-669 Summary of the invention Technical problem to be solved by the invention

[0004] For example, the impeller is fixed to the end of the shaft. In the above structure, when the impeller rotates, the end of the shaft shakes. If the end of the shaft shakes greatly, the vibration and noise of the air supply device will increase.

[0005] An object of the present invention is to suppress vibration and noise of an air supply device. Technical solutions adopted to solve technical problems

[0006] An exemplary air supply device of the present invention comprises: an impeller, which can rotate around a central axis extending up and down; a motor, which rotates the impeller; and a housing, which accommodates the impeller and the motor. The motor comprises: a rotor, which can rotate around a central axis; and a stator, which rotates the rotor. The rotor comprises: a shaft, which extends along the central axis; and a rotor magnet, which is fixed to the radial outer side of the shaft. The impeller is fixed to a position above the fixed position of the rotor magnet in the radial outer side of the shaft. The housing comprises: a first bearing, which supports the shaft rotatably at a position above the fixed position of the rotor magnet and below the fixed position of the impeller; and a second bearing, which supports the shaft rotatably at a position below the fixed position of the rotor magnet. The center of gravity of the impeller is a position overlapping with the upper end of the first bearing when viewed from the radial direction, or a position below the upper end of the first bearing.

[0007] An exemplary hair dryer of the present invention includes the above-mentioned air sending device. Effects of the Invention

[0008] According to the exemplary air blowing device and hair dryer of the present invention, vibration and noise of the air blowing device can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is an exploded perspective view of the air supply device according to the embodiment. Figure 2 It is a cross-sectional view of the air supply device according to the embodiment. Figure 3 It is a cross-sectional perspective view of the housing of the embodiment. Figure 4 It is an enlarged cross-sectional view of the lower bushing and its surroundings according to the embodiment. Figure 5 is an exploded cross-sectional view of a housing of an embodiment. Figure 6 It is a cross-sectional view schematically showing a hair dryer according to the embodiment. (Explanation of symbols) 1 Impeller 2 Motor 3 Shell 11 Base 12 barrel 13 Moving blades 21 rotor 22 stator 31 First Shell 32 Second Shell 100 air supply device 110 bulge 211 axis 212 rotor magnet 213 lower bushing 214 upper bushing 301 first bearing 302 second bearing 310 lower end 311 inner tube 312 outer tube 313 stationary blade 320 upper end 321 lower side tube 1000 hair dryer 2131 radial inner edge CA Central Axis P Center of gravity position DETAILED DESCRIPTION

[0010] Below, refer to the attached Figures 1 to 6 , exemplary embodiments of the present invention are described.

[0011] In this specification, the direction in which the central axis CA of the air supply device 100 extends is referred to as the "axial direction", and the circumferential direction centered on the central axis CA is referred to as the "circumferential direction". In addition, the direction orthogonal to the central axis CA is referred to as the "radial direction". The direction approaching the central axis CA in the radial direction is referred to as the "radial inner direction", and the direction away from the central axis CA is referred to as the "radial outer direction".

[0012] In addition, for convenience, the axial direction is defined as the up-down direction in this specification, and the side where the impeller 1 is arranged is described as the upper side of the air supply device 100. However, the definition of the up-down direction does not limit the actual orientation and positional relationship of each component of the air supply device 100.

[0013] <1. Structure of air supply device> Figure 1 It is an exploded perspective view of the air blowing device 100 according to the embodiment. Figure 2 It is a cross-sectional view of the air blowing device 100 according to the embodiment. Figure 3 It is a cross-sectional perspective view of the housing 3 according to the embodiment. Figure 4 It is an enlarged cross-sectional view of the lower bushing 213 and its surroundings according to the embodiment. Figure 5 It is an exploded cross-sectional view of the housing 3 according to the embodiment. Figure 2 to Figure 5 This corresponds to a cross section of the air supply device 100 cut along a plane including the central axis CA.

[0014] The air blowing device 100 includes an impeller 1, a motor 2, and a housing 3. The impeller 1 is rotatable about a central axis CA extending vertically. The motor 2 rotates the impeller 1. The housing 3 accommodates the impeller 1 and the motor 2.

[0015] <1-1. Impeller> The impeller 1 has a base portion 11. The base portion 11 is in the shape of a disk with the central axis CA as the center. The base portion 11 is fixed to the motor 2. Specifically, the base portion 11 has a protrusion 110 in the radial center portion. The protrusion 110 is a cylindrical portion extending in the axial direction. That is, the base portion 11 has a through hole penetrating in the axial direction in the radial center portion. The protrusion 110 is fixed to the radial outer side surface of the shaft 211 described below. For example, the shaft 211 is pressed into the through hole of the protrusion 110. By fixing the protrusion 110 to the radial outer side surface of the shaft 211, the blade 1 is fixed to the shaft 211.

[0016] The blade 1 has a cylinder 12 and a plurality of moving blades 13. The cylinder 12 extends downward from the radial outer edge of the base 11. That is, the cylinder 12 is cylindrical with the central axis CA as the center. The plurality of moving blades 13 extend radially outward from the radial outer surface of the cylinder 12 and are arranged in the circumferential direction.

[0017] Here, the center of gravity of the impeller 1 is located radially inward of the cylinder 12. When the air supply device 100 is cut along a plane including the central axis CA, as shown in FIG. Figure 2 As shown, the position P indicated by a black circle in the figure is the center of gravity of the impeller 1. The center of gravity P of the impeller 1 overlaps with the central axis CA below the base portion 11 and above the lower end of the cylinder portion 12.

[0018] <1-2. Motor> The motor 2 includes a rotor 21 and a stator 22. The rotor 21 is rotatable about a central axis CA. The stator 22 rotates the rotor 21.

[0019] The rotor 21 has a shaft 211. The shaft 211 extends along the central axis CA. The shaft 211 is supported so as to be rotatable about the central axis CA. By rotating the shaft 211, the impeller 1 fixed to the shaft 211 rotates together with the shaft 211. In addition, the shaft 211 has a groove portion (symbol omitted) extending in the circumferential direction on the radially outer side surface.

[0020] The rotor 21 has a rotor magnet 212. The rotor magnet 212 is cylindrical. The rotor magnet 212 is arranged radially inward of the cylindrical magnet cover 2120. As a result, the radial outer side surface of the rotor magnet 212 is covered by the magnet cover 2120 over the entire surface. In addition, the rotor magnet 212 is fixed to the radial outer side surface of the shaft 211. The impeller 1 is fixed to a position above the fixed position of the rotor magnet 212 in the radial outer side surface of the shaft 211.

[0021] For example, in the process of fixing the rotor magnet 212 to the shaft 211, an adhesive is applied to the groove portion and its periphery in the radial outer side surface of the shaft 211. Then, the shaft 211 is press-fitted into the rotor magnet 212. That is, the rotor magnet 212 is fixed to the radial outer side surface of the shaft 211 by the adhesive.

[0022] The rotor 21 has a lower bushing 213. The lower bushing 213 is fixed to the radial outer side of the shaft 211. The lower bushing 213 is arranged below the rotor magnet 212. Specifically, the lower bushing 213 is axially arranged between the second bearing 302 described below and the rotor magnet 212. The lower bushing 213 is in axial contact with the lower end of the rotor magnet 212. As a result, the axial position deviation of the rotor magnet 212 is suppressed.

[0023] The stator 22 is arranged radially outward of the rotor 21. The stator 22 and the rotor 21 are spaced apart in the radial direction and face each other. Specifically, the stator 22 and the radially outer side surface of the rotor magnet 212 are spaced apart in the radial direction and face each other. The stator 22 is fixed to the housing 3. The stator 22 has a stator core 221, an insulator 222 and a coil 223.

[0024] The stator core 221 is an annular magnetic body centered on the central axis CA, and is a laminated body formed by stacking a plurality of plate-shaped electromagnetic steel sheets in the axial direction. The radial inner side of the stator core 221 is radially spaced apart from the rotor magnet 212. The radial outer side of the stator core 221 is fixed to the housing 3.

[0025] The insulator 222 covers at least a portion of the stator core 221. The insulator 222 is an insulating member made of resin or the like. The coil 223 is formed by winding a conductive wire around the stator core 221 via the insulator 222. The coil 223 is electrically connected to a circuit board (not shown). Various electronic components are mounted on the circuit board.

[0026] <1-3. Casing> The housing 3 includes a first bearing 301 that rotatably supports the shaft 211 and a second bearing 302 that rotatably supports the shaft 211. The first bearing 301 rotatably supports the shaft 211 at a position above the fixed position of the rotor magnet 212 and below the fixed position of the impeller 1. The second bearing 302 rotatably supports the shaft 211 at a position below the fixed position of the rotor magnet 212.

[0027] The housing 3 includes a first housing 31 and a second housing 32. The first housing 31 and the second housing 32 are respectively fixed to the stator 22. The second housing is arranged below the first housing 31. Thus, the first housing 31 and the second housing 32 are fastened in the axial direction.

[0028] The first housing 31 holds the first bearing 301. The first housing 31 has a first holding portion 31a that holds the first bearing 301. The outer ring of the first bearing 301 is fixed to the first holding portion 31a, and the inner ring of the first bearing 301 is fixed to the radially outer side surface of the shaft 211.

[0029] The second housing 32 holds the second bearing 302. The second housing 32 has a second holding portion 32a that holds the second bearing 302. The outer ring of the second bearing 302 is fixed to the second holding portion 32a, and the inner ring of the second bearing 302 is fixed to the radially outer side surface of the shaft 211.

[0030] The first housing 31 has an inner tube portion 311. The inner tube portion 311 is a tube centered on the central axis CA. The first retaining portion 31a is connected to the inner tube portion 311. That is, the inner tube portion 311 has the first retaining portion 31a at the radial center.

[0031] The inner cylinder 311 covers the stator 22 from the radial outside and holds the stator 22. Specifically, the inner cylinder 311 has a rib 3110 on the radial inner side surface that contacts the stator 22. There are multiple ribs 3110. The multiple ribs 3110 protrude radially inward from the radial inner side surface of the inner cylinder 311 and extend in the axial direction. The multiple ribs 3110 are arranged in the circumferential direction. The multiple ribs 3110 contact the stator 22 from the radial outside, thereby holding the stator 22 on the radial inner side of the inner cylinder 311.

[0032] The first housing 31 has an outer tube portion 312. The outer tube portion 312 is cylindrical centered on the central axis CA. The outer tube portion 312 is arranged radially outward of the inner tube portion 311 and spaced apart from the inner tube portion 311. The outer tube portion 312 forms an airflow passage with the inner tube portion 311 in the radial direction.

[0033] The first housing 31 has a stationary blade 313. The stationary blade 313 is disposed between the inner tube portion 311 and the outer tube portion 312 in the radial direction. The stationary blade 313 connects the inner tube portion 311 and the outer tube portion 312. There are a plurality of stationary blades 313. The plurality of stationary blades 313 are arranged in the circumferential direction.

[0034] By rotating the impeller 1, an airflow from top to bottom is generated between the inner tube 311 and the outer tube 312 in the radial direction. At this time, the airflow between the inner tube 311 and the outer tube 312 in the radial direction is smoothly circulated by the plurality of stationary blades 313.

[0035] <2. Position of the first bearing> In the structure in which the impeller 1 is fixed to the upper end of the shaft 211, if the upper end of the shaft 211 is not supported, the shaking of the shaft 211 becomes larger, which becomes a cause of vibration and noise. On the other hand, in the structure in which the upper end of the shaft 211 is supported to be rotatable by the first bearing 301 (i.e., in the structure of the present embodiment), the vibration and noise caused by the rotation of the impeller 1 can be suppressed. However, if the interval between the center of gravity position P of the impeller 1 and the axial direction of the first bearing 301 becomes larger, the effect of suppressing vibration and noise is reduced. The larger the interval between the center of gravity position P of the impeller 1 and the axial direction of the first bearing 301, the greater the shaking of the shaft 211, and the easier it is to generate vibration and noise. Therefore, it is preferred that the interval between the center of gravity position P of the impeller 1 and the axial direction of the first bearing 301 is small.

[0036] Therefore, in this embodiment, if Figure 2 As shown, the center of gravity position P of the impeller 1 is a position overlapping with the upper end of the first bearing 301 when viewed from the radial direction, or a position lower than the upper end of the first bearing 301. That is, when viewed from the radial direction, the center of gravity position P of the impeller 1 overlaps with the first bearing 301. As a result, the shaft 211 is not easy to shake when the impeller 1 rotates. As a result, vibration and noise can be suppressed. In addition, it is preferred that the center of gravity position P of the impeller 1 is within the range from the upper end to the lower end of the first bearing 301 when viewed from the radial direction. Therefore, in the present embodiment, the center of gravity position P of the impeller 1 is a position overlapping with the lower end of the first bearing 301 when viewed from the radial direction, or a position higher than the lower end of the first bearing 301. As a result, the center of gravity interval between the impeller 1 and the first bearing 301 in the axial direction becomes smaller, which is more effective in suppressing vibration and noise.

[0037] Furthermore, in the present embodiment, the radial center portion of the impeller 1 is hollow, and therefore, more than half of the first bearing 201 from the upper end toward the lower end is arranged radially inward of the cylinder 12. That is, the axial center of the first bearing 301 is located above the lower end of the cylinder 12. In the present embodiment, when viewed from the radial direction, all portions of the first bearing 301 are arranged radially inward of the cylinder 12. Thus, it is easy to achieve that the center of gravity position P of the impeller 1 overlaps with the first bearing 301 when viewed from the radial direction. In addition, in Figure 2 In order to make the lower end position of the cylinder 12 clear, the lower end position of the cylinder 12 is indicated by “PL”.

[0038] Furthermore, in the present embodiment, the protrusion 110 protrudes upward from the upper surface of the base portion 11. For example, when the protrusion 110 is made smaller in the axial direction without protruding upward from the upper surface of the base portion 11, it is possible to ensure a configuration space for the first bearing 301 on the radially inner side of the cylinder portion 12, but the fixation of the protrusion 110 to the shaft 211 is weakened. However, when the protrusion 110 is made larger in the axial direction on the radially inner side of the cylinder portion 12 in order to suppress the weakening of the fixation of the protrusion 110 to the shaft 211, it is not possible to ensure a sufficient configuration space for the first bearing 301 on the radially inner side of the cylinder portion 12.

[0039] On the other hand, in this embodiment, by making the protrusion 110 protrude upward from the upper surface of the base portion 11, it is possible to prevent the protrusion 110 from becoming smaller in the axial direction, and to ensure sufficient space for arranging the first bearing 301 in the radially inner side of the cylinder portion 12. Therefore, even if the first bearing 301 is arranged in the radially inner side of the cylinder portion 12, it is possible to prevent the fixation of the protrusion 110 with respect to the shaft 211 from becoming weak.

[0040] Furthermore, in the present embodiment, the lower end of the first bearing 301 is located above the upper end of the stationary blade 313. Here, in the present embodiment, the impeller 1 is arranged above the stationary blade 313. Therefore, by arranging the first bearing 301 in such a manner that the lower end of the first bearing 301 is located above the upper end of the stationary blade 313, it is possible to easily achieve that the center of gravity position P of the impeller 1 overlaps with the first bearing 301 when viewed from the radial direction. Figure 2 In order to make the upper end position of the stationary blade 313 clear, the upper end position of the stationary blade 313 is represented by “PT”.

[0041] <3. Reinforcement of the shaft by the upper bushing> In the structure in which the first bearing 301 is arranged radially inward of the cylinder 12, the axial position of the first bearing 301 needs to be displaced upward. That is, the axial distance between the rotor magnet 212 and the first bearing 301 becomes larger. In this case, if the portion between the rotor magnet 212 and the first bearing 301 in the axial direction of the shaft 211 is not reinforced, the shaft 211 may bend or the like.

[0042] Therefore, in the present embodiment, the rotor 21 has an upper bushing 214. The upper bushing 214 is fixed to the radial outer side of the shaft 211. The upper bushing 214 is arranged between the rotor magnet 212 and the first bearing 301 in the axial direction. In addition, a gap is provided in the axial direction between the rotor magnet 212 and the upper bushing 214. However, the upper bushing 214 may also contact the upper end of the rotor magnet 212 in the axial direction.

[0043] By arranging the upper bushing 214 between the rotor magnet 212 and the first bearing 301 in the shaft 211 in the axial direction, the rigidity of the shaft 211 is improved. As a result, the shaft 211 is less likely to bend.

[0044] <4. Fixing of the lower bushing to the rotor magnet> When the shaft 211 is pressed into the rotor magnet 212, the adhesive applied to the radially outer surface of the shaft 211 flows downward and reaches the upper end surface of the lower bushing 213. Thus, the rotor magnet 212 and the lower bushing 213 can be fixed by the adhesive.

[0045] Here, if the upper end surface of the lower bushing 213 is flat, the adhesive easily flows in the radial direction from the upper end surface of the lower bushing 213. Therefore, the adhesive existing between the rotor magnet 212 and the lower bushing 213 in the axial direction is reduced.

[0046] Therefore, in this embodiment, if Figure 4 As shown, the radial inner edge portion 2131 of the lower bushing 213 is recessed to a position lower than the upper end surface of the lower bushing 213. In the above structure, an annular recess is formed by the radial outer side surface of the shaft 211 and the radial inner edge portion 2131 of the lower bushing 213. As a result, the adhesive flowing downward on the radial outer side surface of the shaft 211 is accumulated in the radial inner edge portion 2131. As a result, the fixing between the shaft 211 and the lower bushing 213 by the adhesive can be strengthened.

[0047] In addition, the radial inner edge portion 2131 of the lower bushing 213 is recessed to a position lower than the upper end surface of the lower bushing 213. Here, in order to fix the magnet cover 2120 to the radial outer side surface of the rotor magnet 212, an adhesive is applied to the radial outer side surface of the rotor magnet 212. The adhesive applied to the radial outer side surface of the rotor magnet 212 flows downward on the radial outer side surface of the rotor magnet 212 and accumulates in the radial outer edge portion 2132 of the lower bushing 213. As a result, the fixation between the rotor magnet 212 and the magnet cover 2120 based on the adhesive can be strengthened.

[0048] <5. Fixing the housing and stator> In this embodiment, if Figure 3 and Figure 5 As shown, the second housing 32 has a lower cylinder 321. The lower cylinder 321 is cylindrical centered on the central axis CA. In addition, the second retaining portion 32a is connected to the lower cylinder 321. That is, the lower cylinder 321 has the second retaining portion 32a at the radial center.

[0049] In fixing the housing 3 and the stator 22, the portion of the stator 22 above the lower end is pressed into the inner tube 311, and the lower end of the stator 22 is pressed into the lower tube 321. When the stator 22 is pressed into both the inner tube 311 and the lower tube 321, the lower end 310 of the inner tube 311 and the upper end 320 of the lower tube 321 overlap in the radial direction.

[0050] Here, the stationary blade 313 is connected to the inner cylinder portion 311. In this structure, if the upper end portion 320 of the lower cylinder portion 321 is to overlap with the lower end portion 310 of the inner cylinder portion 311 from the radial outside, it is necessary to take measures such as making the stationary blade 313 smaller in the axial direction to ensure space for the lower end portion 310 of the inner cylinder portion 311 and the upper end portion 320 of the lower cylinder portion 321 to overlap.

[0051] Here, in the present embodiment, the inner diameter of the lower end portion 310 of the inner cylinder portion 311 is enlarged compared to the portion of the inner cylinder portion 311 that is above the lower end portion 310. In other words, the lower end portion 310 of the inner cylinder portion 311 is more radially outwardly recessed than the portion of the inner cylinder portion 311 that is above the lower end portion 310 over the entire circumference. In addition, the lower end portion 310 of the inner cylinder portion 311 does not have a rib 3110 on its radial inner circumferential surface. Therefore, the lower end portion 310 of the inner cylinder portion 311 does not contact the stator 22, and a gap is provided between the lower end portion 310 of the inner cylinder portion 311 and the stator 22 in the radial direction.

[0052] Furthermore, the upper end portion 320 of the lower cylinder portion 321 is disposed in the radial gap between the lower end portion 310 of the inner cylinder portion 311 and the stator 22. That is, the upper end portion 320 of the lower cylinder portion 321 is disposed radially inward of the lower end portion 310 of the inner cylinder portion 311. Thus, there is no need to take measures such as reducing the size of the stationary blades 313 in the axial direction.

[0053] <6.Use example> Figure 6 1 is a cross-sectional view schematically showing a hair dryer 1000 according to the embodiment.

[0054] The hair dryer 1000 includes an air blowing device 100. In addition, the hair dryer 1000 includes a main body 1001, a handle 1002, and a heater 1003.

[0055] The main body 1001 is cylindrical. The handle 1002 is cylindrical. The upper end of the handle 1002 is connected to the trunk of the main body 1001. The interiors of the main body 1001 and the handle 1002 are connected to each other. The heater 1003 is arranged inside the main body 1001. The air supply device 100 is arranged inside the handle 1002. Inside the handle 1002, the state of the air supply device 100 becomes the same as that of the main body 1001. Figure 2 The states shown are reversed.

[0056] The air supply device 100 is driven to introduce air from the lower end of the handle 1002 into the handle 1002, generating airflow. The airflow flows axially inside the main body 1001 and is heated by the heater 1003. Thus, warm air is discharged from the main body 1001.

[0057] In the hair dryer 1000 of the present embodiment, vibration and noise can be suppressed by using the air sending device 100 .

[0058] <7. Others> The above is an explanation of the embodiments of the present invention. In addition, the scope of the present invention is not limited by the above embodiments. The present invention can be implemented by adding various changes within the scope of the invention. Moreover, the above embodiments can be appropriately combined arbitrarily.

[0059] The present invention can adopt the following structures (1) to (9).

[0060] (1) An air supply device comprising: an impeller, the impeller being rotatable about a central axis extending vertically; a motor that rotates the impeller; and a housing for housing the impeller and the motor; The motor has: a rotor rotatable about the central axis; and a stator, the stator causing the rotor to rotate, The rotor has: a shaft extending along the central axis; and a rotor magnet, wherein the rotor magnet is fixed to the radial outer side of the shaft, The impeller is fixed to a position on the radially outer side surface of the shaft that is above a position where the rotor magnet is fixed. The housing has: a first bearing that rotatably supports the shaft at a position above a fixed position of the rotor magnet and below a fixed position of the impeller; and a second bearing that rotatably supports the shaft at a position below a fixed position of the rotor magnet; The center of gravity of the impeller is located at a position overlapping with the upper end of the first bearing or at a position below the upper end of the first bearing when viewed from the radial direction.

[0061] (2) In the air blowing device described in (1), the center of gravity of the impeller is located at a position overlapping with the lower end of the first bearing or at a position above the lower end of the first bearing when viewed from the radial direction.

[0062] (3) In the air supply device described in (1) or (2), the impeller has: A base portion, wherein the base portion has a protrusion at a radial center portion, and the protrusion is fixed to a radial outer side surface of the shaft; a cylindrical portion extending downward from a radially outer edge portion of the base portion; and a plurality of moving blades, the plurality of moving blades extending radially outward from the radially outer side of the cylinder portion and arranged in a circumferential direction, The center of gravity of the impeller is located radially inward of the cylinder. The axial center of the first bearing is located above the lower end of the cylindrical portion.

[0063] (4) In the air blowing device described in (3), the projection protrudes upward from the upper surface of the base portion.

[0064] (5) In the air supply device described in any one of (1) to (4), the housing has: a first housing holding the first bearing; and a second housing holding the second bearing, The first housing has: An inner cylindrical portion, the inner cylindrical portion is in a cylindrical shape centered on the central axis, covers the stator from the outside in the radial direction, and holds the stator; an outer cylindrical portion, the outer cylindrical portion being in a cylindrical shape centered on the central axis, and being arranged radially outward of the inner cylindrical portion at a distance from the inner cylindrical portion to form an air flow passage in the radial direction with the inner cylindrical portion; and A stationary blade is arranged between the inner tube portion and the outer tube portion in a radial direction, and a lower end of the first bearing is located above an upper end of the stationary blade.

[0065] (6) In the air supply device described in any one of (1) to (5), the rotor has an upper bushing fixed to the radially outer side surface of the shaft, The upper bushing is arranged between the rotor magnet and the first bearing in an axial direction.

[0066] (7) In the air supply device described in any one of (1) to (6), the rotor has a lower bushing fixed to the radially outer side surface of the shaft, The lower bushing is arranged below the rotor magnet. The rotor magnet is fixed to the radial outer side of the shaft by an adhesive. The radial inner edge portion of the lower bushing is recessed below an upper end surface of the lower bushing.

[0067] (8) In the air supply device described in any one of (1) to (7), the housing has: a first housing holding the first bearing; and a second housing holding the second bearing, The first housing has: An inner cylindrical portion, the inner cylindrical portion is in a cylindrical shape centered on the central axis, covers the stator from the outside in the radial direction, and holds the stator; an outer cylindrical portion, the outer cylindrical portion being in a cylindrical shape centered on the central axis, and being arranged radially outward of the inner cylindrical portion at a distance from the inner cylindrical portion to form an air flow passage in the radial direction with the inner cylindrical portion; and a stationary blade, the stationary blade being arranged between the inner tube portion and the outer tube portion in a radial direction, The inner diameter of the lower end of the inner tube portion is enlarged compared to the portion of the inner tube portion that is above the lower end. The second housing has a lower cylindrical portion, and the lower cylindrical portion is cylindrical with the central axis as the center. The upper end portion of the lower cylindrical portion is arranged radially inward of the lower end portion of the inner cylindrical portion.

[0068] (9) A hair dryer comprising the air supply device according to any one of (1) to (8). Industrial Applicability

[0069] The present invention can be used, for example, in an air supply device installed in a hair dryer or the like.

Claims

1. An air supply device, characterized in that: have: An impeller, the impeller being rotatable about a central axis extending vertically; a motor that rotates the impeller; and a housing for housing the impeller and the motor; The motor has: a rotor rotatable about the central axis; and a stator, the stator causing the rotor to rotate, The rotor has: a shaft extending along the central axis; and a rotor magnet, wherein the rotor magnet is fixed to the radial outer side of the shaft, The impeller is fixed to a position on the radially outer side surface of the shaft that is above a position where the rotor magnet is fixed. The housing has: a first bearing that rotatably supports the shaft at a position above a fixed position of the rotor magnet and below a fixed position of the impeller; as well as a second bearing that rotatably supports the shaft at a position below a fixed position of the rotor magnet; The center of gravity of the impeller is located at a position overlapping with the upper end of the first bearing or at a position below the upper end of the first bearing when viewed from the radial direction.

2. The air supply device according to claim 1, characterized in that: The center of gravity of the impeller is located at a position overlapping with the lower end of the first bearing or at a position above the lower end of the first bearing when viewed from the radial direction.

3. The air supply device according to claim 1, characterized in that: The impeller has: A base portion, wherein the base portion has a protrusion at a radial center portion, and the protrusion is fixed to a radial outer side surface of the shaft; a cylindrical portion extending downward from a radially outer edge portion of the base portion; as well as a plurality of moving blades, the plurality of moving blades extending radially outward from the radially outer side of the cylinder portion and arranged in a circumferential direction, The center of gravity of the impeller is located radially inward of the cylinder. The axial center of the first bearing is located above the lower end of the cylindrical portion.

4. The air supply device according to claim 3, characterized in that: The protrusion protrudes upward from the upper surface of the base portion.

5. The air supply device according to claim 1, characterized in that: The housing has: a first housing holding the first bearing; and a second housing holding the second bearing, The first housing has: An inner cylindrical portion, the inner cylindrical portion is in a cylindrical shape centered on the central axis, covers the stator from the outside in the radial direction, and holds the stator; an outer cylindrical portion, the outer cylindrical portion being in a cylindrical shape centered on the central axis, and being arranged radially outward of the inner cylindrical portion at a distance from the inner cylindrical portion to form an air flow passage in the radial direction with the inner cylindrical portion; and a stationary blade, the stationary blade being arranged between the inner tube portion and the outer tube portion in a radial direction, The lower end of the first bearing is located above the upper end of the stationary blade.

6. The air supply device according to claim 1, characterized in that: The rotor has an upper bushing fixed to the radial outer side of the shaft. The upper bushing is arranged between the rotor magnet and the first bearing in an axial direction.

7. The air supply device according to claim 1, characterized in that: The rotor has a lower bushing fixed to the radial outer side of the shaft. The lower bushing is arranged below the rotor magnet. The rotor magnet is fixed to the radial outer side of the shaft by an adhesive. The radial inner edge portion of the lower bushing is recessed below an upper end surface of the lower bushing.

8. The air supply device according to claim 1, characterized in that: The housing has: a first housing holding the first bearing; and a second housing holding the second bearing, The first housing has: An inner cylindrical portion, the inner cylindrical portion is in a cylindrical shape centered on the central axis, covers the stator from the outside in the radial direction, and holds the stator; an outer cylindrical portion, the outer cylindrical portion being in a cylindrical shape centered on the central axis, and being arranged radially outward of the inner cylindrical portion at a distance from the inner cylindrical portion to form an air flow passage in the radial direction with the inner cylindrical portion; and a stationary blade, the stationary blade being arranged between the inner tube portion and the outer tube portion in a radial direction, The inner diameter of the lower end of the inner tube portion is enlarged compared to the portion of the inner tube portion that is above the lower end. The second housing has a lower cylindrical portion, and the lower cylindrical portion is cylindrical with the central axis as the center. The upper end portion of the lower cylindrical portion is arranged radially inward of the lower end portion of the inner cylindrical portion.

9. A hair dryer, characterized in that: A fan device according to claim 1 is provided.

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