Blower

Abstract

A blower (10) comprises a housing (60), a sleeve (70), a shaft (314), a propeller, and a lubricating oil (90). The housing (60) has a recess that opens upward. The sleeve (70) has a through-hole (71). The sleeve (70) is disposed in the recess. The shaft (314) penetrates the through-hole (71). The propeller is connected to an upper end of the shaft (314). The lubricating oil (90) is accommodated in the recess. The sleeve (70) has an upper part (74) and a lower part (75) positioned below the upper part (74). The recess is filled with the lubricating oil (90) to a level above the lower part (75). An outer peripheral surface (751) of the lower part (75) is positioned inside an outer peripheral surface (741) of the upper part (74) when viewed from below. When viewed from below, the distance between the outer peripheral surface (751) of the lower part (75) and the outer peripheral surface (741) of the upper part (74) increases along the circumferential direction.

Description

blower

[0001] The present disclosure relates to a blower.

[0002] 2. Description of the Related Art Conventionally, a hydrodynamic bearing device is known in which a working fluid (lubricating oil) is filled between a shaft and a sleeve that rotatably holds the shaft (see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2008-248916

[0004] In a blower equipped with a fluid dynamic bearing device such as that described in Patent Document 1, air bubbles contained in the lubricating oil can sometimes hinder the circulation of the lubricating oil, so there has been a demand for a way to expel the air bubbles contained in the lubricating oil to the outside.

[0005] A blower according to one aspect of the present disclosure includes a housing having a recess that opens upward, a sleeve having a through hole and disposed within the recess, a shaft that passes through the through hole, a propeller connected to the upper end of the shaft, and lubricating oil contained within the recess. The sleeve has an upper portion and a lower portion located below the upper portion. The lubricating oil is filled within the recess up to a position above the lower portion. The outer peripheral surface of the lower portion includes a first outer peripheral surface, and the first outer peripheral surface of the lower portion is located more inward than the outer peripheral surface of the upper portion when viewed from below. When viewed from below, at least a portion of the distance between the first outer peripheral surface of the lower portion and the outer peripheral surface of the upper portion is elongated along the circumferential direction of the outer peripheral surface of the upper portion.

[0006] A blower according to another aspect of the present disclosure includes a housing having a recess that opens upward, a sleeve having a through hole and disposed within the recess, a shaft that passes through the through hole, a propeller connected to the upper end of the shaft, and lubricating oil contained within the recess. The housing has an upper portion and a lower portion located below the upper portion. The lubricating oil is filled in the recess up to a position above the lower portion. The inner circumferential surface of the lower portion includes a first inner circumferential surface, and the first inner circumferential surface of the lower portion is located more inward than the inner circumferential surface of the upper portion when viewed from above. When viewed from above, the distance between the first inner circumferential surface of the lower portion and the inner circumferential surface of the upper portion decreases along the circumferential direction of the second inner circumferential surface of the upper portion.

[0007] According to the present disclosure, it is possible to easily discharge air bubbles contained in lubricating oil to the outside.

[0008] FIG. 1 is a perspective view showing the appearance of a blower according to the first and second embodiments of the present disclosure. FIG. 2 is a cross-sectional perspective view taken along an XZ plane including line Y1-Y1 in FIG. 1 . FIG. 3 is an exploded perspective view of a bearing and a shaft included in the blower. FIG. 4 is a top view of a housing included in the blower. FIG. 5 is a perspective view of a first cap included in the blower as viewed from above. FIG. 6 is a perspective view of a first cap included in the blower as viewed from below. FIG. 7 is a cross-sectional view of a sleeve taken along an XZ plane including line Y2-Y2 in FIG. 3 . FIG. 8 is a cross-sectional view taken from a front view along an XZ plane including line Y1-Y1 in FIG. 1 . FIG. 9 is a cross-sectional view taken from a bottom view along an XY plane including line Z1-Z1 in FIG. 1 . FIG. 10 is a cross-sectional view taken from a front view of a blower according to a modification of the first embodiment. FIG. 11 is a cross-sectional view taken from a bottom view of a blower according to a modification of the first embodiment. Fig. 12 is a perspective view of a bearing and a shaft of a blower according to a second embodiment of the present disclosure. Fig. 13 is a cross-sectional view as viewed from the front, taken along an XZ plane including line Y3-Y3 in Fig. 12. Fig. 14 is a cross-sectional view as viewed from below, taken along an XY plane including line Z2-Z2 in Fig. 12.

[0009] A blower 10 according to an embodiment of the present disclosure will be described in detail with reference to the drawings. Note that the drawings referred to in the following description are schematic diagrams, and the ratios of the sizes and thicknesses of the components in the drawings do not necessarily reflect the actual dimensional ratios. Furthermore, the embodiment and modified examples described below are merely examples of the present disclosure, and the present disclosure is not limited to the embodiment and modified examples. Various modifications other than these embodiment and modified examples are possible depending on the design, etc., as long as they do not deviate from the technical concept of the present disclosure.

[0010] First Embodiment (1) Overview First, an overview of a blower 10 according to a first embodiment will be described with reference to FIGS. 1, 2, 8, and 9. FIG.

[0011] The blower 10 includes a housing 60 , a sleeve 70 , a shaft 314 , a propeller 31 , and lubricating oil 90 .

[0012] The housing 60 has a recess 63 that opens upward.

[0013] The sleeve 70 has a through hole 71. The sleeve 70 is disposed in the recess 63.

[0014] The shaft 314 passes through the through-hole 71 .

[0015] The propeller 31 is connected to the upper end of the shaft 314 .

[0016] The lubricating oil 90 is contained within the recess 63 .

[0017] The sleeve 70 also has an upper portion 74 and a lower portion 75 located below the upper portion 74 .

[0018] The lubricating oil 90 is filled in the recess 63 up to a position above the lower portion 75 .

[0019] An outer peripheral surface 751 of the lower portion 75 is located more inward than an outer peripheral surface 741 of the upper portion 74 when viewed from below.

[0020] When viewed from below, the distance between the outer peripheral surface 751 of the lower portion 75 and the outer peripheral surface 741 of the upper portion 74 (hereinafter referred to as the first inter-surface distance) is at least partially elongated along the circumferential direction of the outer peripheral surface 741 .

[0021] Here, the "circumferential direction of the outer peripheral surface 741" refers to the rotation direction of the propeller 31. In other words, the "circumferential direction of the outer peripheral surface 741" can be rephrased as the circumferential direction centered on the central axis A1 (see FIG. 9 ) of the shaft 314.

[0022] In this embodiment, the "first inter-surface distance" is the distance between a first point and a second point defined below. The first point is any point on the "outer peripheral surface 751 of the lower portion 75." The second point is the intersection of a line passing through the first point and the central axis A1 of the shaft 314 and the "outer peripheral surface 741 of the upper portion 74" when viewed from the top-bottom direction.

[0023] According to the above configuration, for example, the first inter-surface distance is longer in one circumferential direction of the outer peripheral surface 741 (counterclockwise in FIG. 9 ). In other words, the first inter-surface distance is shorter in the other circumferential direction (clockwise in FIG. 9 ) centered on the up-down direction. This causes capillary action, and the lubricating oil 90 moves clockwise within the space S1 between the outer peripheral surface 751 and the outer peripheral surface 741. Accordingly, air bubbles B1 (see FIG. 9 ) generated within the lubricating oil 90 move counterclockwise within the space S1. This prevents the air bubbles B1 from stagnating within the recess 63, making it easier for the air bubbles B1 to be discharged to the outside of the recess 63.

[0024] (2) Details The blower 10 according to this embodiment will be described in detail with reference to the drawings.

[0025] In the following description and in the drawings, the axial direction of the shaft 314 of the blower 10 is defined as the Z-axis direction, and the directions perpendicular to each other in a plane perpendicular to the Z-axis direction are defined as the X-axis direction and the Y-axis direction. Note that, depending on the mode of use, the Z-axis may not be the up-down direction, but for the sake of convenience, the following description will be made assuming that the Z-axis direction is the up-down direction. Also, the arrows indicating the directions in the drawings are merely shown for the purpose of explanation and do not have any substance.

[0026] In the following description, expressions indicating relative directions or attitudes, such as "parallel" and "orthogonal," also include cases where the directions or attitudes are not strictly the same. That is, "two directions are parallel" does not only mean that the two directions are completely parallel, but also means that the directions are substantially parallel, i.e., there is a difference of, for example, a few percent. Furthermore, "two directions are orthogonal" does not only mean that the two directions are completely orthogonal, but also means that the angle between the two directions has a difference of, for example, a few percent from 90°.

[0027] (2.1) Configuration First, the configuration of the blower 10 according to the embodiment will be described.

[0028] 1 and 2, blower 10 has a frame 20, a rotor unit 30, a stator unit 40, and a bearing unit 50. Fig. 2 is a cross-sectional perspective view taken along an XZ plane including line Y1-Y1 in Fig. 1.

[0029] (2.1.1) Frame The frame 20 is a member that houses the rotor unit 30, the stator unit 40, and the bearing unit 50, and has a cylindrical opening 21 that is open in the vertical direction. At the lower end of the opening 21, multiple beams 22 (see FIG. 2) are arranged radially, extending from the inner edge of the opening 21 toward the center. A base 23 that holds the rotor unit 30, the stator unit 40, and the bearing unit 50 is connected to the tips of the multiple beams 22. In other words, the base 23 is arranged in the center of the opening 21.

[0030] (2.1.2) Rotor Section The rotor section 30 has a propeller 31, a yoke 32, and a magnet 33. The propeller 31 has a cylindrical main body 311 with a bottom, and a plurality of blades 312 extending outward from the periphery of the main body 311.

[0031] The main body 311 has a cylindrical shape with an upper bottom 313 and an open bottom. A cylindrical yoke 32 is attached to the inner peripheral surface of the main body 311, and a cylindrical magnet 33 is attached to the inner peripheral surface of the yoke 32. A columnar shaft 314, whose axial direction is in the Z-axis direction, is fixed to the center of the bottom 313.

[0032] (2.1.3) Stator Section The stator section 40 generates magnetic flux in response to the drive current. The stator section 40 includes a stator core 41, multiple coils 42 attached to the stator core 41, and a circuit board 43 for supplying power to each coil 42. The stator core 41 is made of laminated steel plates, for example, in which electromagnetic steel plates such as silicon steel plates are stacked in the axial direction. The stator core 41 is fixed directly or indirectly to the base 23. The stator core 41 has multiple teeth 411 protruding outward, and each coil 42 is attached to each tooth 411. As a result, the multiple coils 42 are arranged at equal intervals in the circumferential direction around the stator core 41. The multiple coils 42 are an assembly of wound conductors and are electrically connected to the circuit board 43 located directly below each coil 42. Each coil 42 is arranged inside the yoke 32 and magnet 33.

[0033] (2.1.4) Bearing Unit The bearing unit 50 will be described in detail. The bearing unit 50 is a portion that rotatably supports the shaft 314, the upper end of which is connected to the propeller 31. Figure 3 is an exploded perspective view of the bearing unit 50 and the shaft 314 according to the embodiment. As shown in Figure 3, the bearing unit 50 has a housing 60, a sleeve 70, and a cap unit 80.

[0034] The housing 60 is a member that accommodates a portion of the shaft 314, the sleeve 70, and the cap portion 80. FIG. 4 is a top view of the housing 60. As shown in FIGS. 3 and 4 , the housing 60 has a disk-shaped base 61 and a cylindrical tube portion 62 that protrudes upward from the base 61. The tube portion 62 has an open upper end and a bottom at its lower end. Therefore, the interior of the tube portion 62 forms a columnar recess 63 with an opening at the top. Lubricating oil 90 is contained within the recess 63. A groove (first groove) 64 extending from the upper end to the bottom along the Z-axis is formed on the inner circumferential surface 630 of the recess 63 at the end in the negative direction of the X-axis. The first groove 64 is recessed outward (in the negative direction of the X-axis) from the inner circumferential surface 630 of the recess 63.

[0035] As shown in Fig. 4, a circular depression 631 is formed in the center of the bottom surface of the recess 63. A receiving plate 632 that receives the tip of the shaft 314 is disposed within the depression 631, as shown in Fig. 8. Fig. 8 is a cross-sectional view taken along the XZ plane including the Y1-Y1 line in Fig. 1. The XZ plane including the Y1-Y1 line passes through the central axis of the shaft 314.

[0036] As shown in FIGS. 4 and 8, a groove (second groove) 65 is formed on the bottom surface of the recess 63, extending along the X-axis direction and connecting the first groove 64 and the recess 631.

[0037] 3, the cap portion 80 includes a first cap 81 and a second cap 82 disposed above the first cap 81. The cap portion 80 also includes a retaining plate 83 disposed between the first cap 81 and the second cap 82. The first cap 81, the second cap 82, and the retaining plate 83 are disposed above the sleeve 70 with the shaft 314 passing through them.

[0038] Fig. 5 is a perspective view of the first cap 81 as seen from above. Fig. 6 is a perspective view of the first cap 81 according to the embodiment as seen from below. The first cap 81 is formed, for example, by pressing a metal plate. The first cap 81 may also be formed, for example, from a resin. The first cap 81 has a truncated cone portion 811 and a flange portion 812 that protrudes outward from the periphery of the truncated cone portion 811.

[0039] A first through-hole 813 is formed in the center of the truncated cone portion 811. The shaft 314 passes through the first through-hole 813. An air vent 814 is provided at the end of the inner circumferential surface of the first through-hole 813 in the negative direction of the X-axis. The air vent 814 is a semicircular notch.

[0040] The flange 812 has a ridge 816 formed at its end facing the negative X-axis direction, which ridge 816 protrudes upward and extends in the X-axis direction. The space below this ridge 816 penetrates in the X-axis direction and serves as a flow path for the lubricating oil 90. The end of the ridge 816 facing the negative X-axis direction is a lid 817 that is disposed within the first groove 64. The lid 817 closes the upper surface of the first groove 64. The lid 817 protrudes in the negative X-axis direction to correspond to the first groove 64.

[0041] A slit 818 extending in the X-axis direction is formed at the end of the flange 812 facing the positive X-axis. The end of the slit 818 facing the positive X-axis direction is open, and the end facing the negative X-axis direction extends into the truncated cone portion 811.

[0042] The retaining plate 83 is a disk-shaped member. The retaining plate 83 is made of, for example, resin. Note that the retaining plate 83 may also be formed by, for example, pressing metal. A second through-hole 831 is provided in the center of the retaining plate 83. The shaft 314 passes through the second through-hole 831. A plurality of (for example, four) protrusions 832 that protrude inward are provided on the periphery of the second through-hole 831. The plurality of protrusions 832 have the function of fixing the shaft 314 so that it does not slip out upward.

[0043] The second cap portion 82 (see FIG. 3 ) is formed, for example, in a cylindrical shape with a bottom and an upper surface serving as the bottom. The second cap portion 82 is formed, for example, by pressing a metal plate. The second cap 82 may be formed, for example, from a resin or the like. A third through-hole 821 is provided in the center of the upper surface of the second cap portion 82. The shaft 314 passes through the third through-hole 821. The second cap portion 82 houses the retaining plate 83 therein.

[0044] The sleeve 70 is disposed in the recess 63. As shown in Figures 3 and 7, the sleeve 70 is a cylindrical member, and has a through-hole 71 extending in the Z-axis direction formed in the center. Here, Figure 7 is a cross-sectional view of the sleeve 70, taken along the XZ plane including the line Y2-Y2 in Figure 3.

[0045] The through hole 71 is positioned so that the shaft 314 passes through it. A plurality of guide grooves 72 are formed on the inner circumferential surface (inner side surface) of the sleeve 70, i.e., the inner circumferential surface forming the through hole 71. The guide grooves 72 are arranged at predetermined intervals in the circumferential direction centered on the Z-axis direction. The upper and lower portions of each guide groove 72 are bent, with the intermediate portion being linear along the Z-axis direction. For example, when the shaft 314 rotates counterclockwise in a top view, the upper and lower portions of each guide groove 72 have a bent shape that tapers toward the end of the shaft 314's rotation direction. Lubricating oil 90 is filled between the shaft 314 and the sleeve 70. When the shaft 314 rotates, the shape of each guide groove 72 described above causes the lubricating oil 90 to collect near the apex of the guide groove 72, increasing dynamic pressure. This allows the shaft 314 and the sleeve 70 to maintain a non-contact state. Furthermore, the lubricating oil 90 can be propelled downward.

[0046] A protrusion 73 that protrudes upward is formed around the through hole 71 on the upper surface of the sleeve 70. The outer peripheral surface of the protrusion 73 is a tapered surface that tapers upward. The portion of the upper surface of the sleeve 70 other than the protrusion 73 and the tip surface (upper surface) of the protrusion 73 are flat surfaces.

[0047] 7 to 9, the sleeve 70 has an upper portion 74 and a lower portion 75 located below the upper portion 74. Here, Fig. 9 is a cross-sectional view taken along the XY plane including the Z1-Z1 line in Fig. 1 as viewed from below. In the following description, "viewed from the vertical direction" refers to both a view from above and a view from below.

[0048] The upper part 74 is cylindrical, and the outer diameter of the upper part 74 is slightly larger than the inner diameter of the recessed part 63. Therefore, by press-fitting the upper part 74 of the sleeve 70 into the recessed part 63, the sleeve 70 is fixed in an unrotatable state relative to the recessed part 63. In this state, the outer peripheral surface 741 of the upper part 74 is in contact with the inner peripheral surface 630 of the recessed part 63.

[0049] At least a portion of the outer peripheral surface 751 of the lower portion 75 is located more inward than the outer peripheral surface 741 of the upper portion 74 when viewed in the vertical direction. In this embodiment, as shown in FIG. 9 , the outer peripheral surface 751 of the lower portion 75 is located more inward than the outer peripheral surface 741 of the upper portion 74 around the entire circumferential circumference centered in the vertical direction when viewed in the vertical direction. In other words, when the sleeve 70 is fixed to the recess 63, the outer peripheral surface 751 of the lower portion 75 faces the inner peripheral surface 630 of the recess 63, which contacts the outer peripheral surface 741 of the upper portion 74, across a space S1. Here, the lubricating oil 90 is filled in the recess 63 up to a position above the lower portion 75. This allows the lubricating oil 90 to be stored in the space S1.

[0050] As described above, the first groove 64 extending along the Z-axis direction from the top end to the bottom is formed at the end of the inner circumferential surface 630 of the recess 63 in the negative direction of the X-axis. Therefore, the sleeve 70 is disposed within the recess 63 such that at least a portion of the outer circumferential surface 751 of the lower portion 75 faces the first groove 64.

[0051] The shape of the lower portion 75 of the sleeve 70 will be described in more detail below.

[0052] To explain the shape of the lower portion 75, multiple points P1 to P4 (see FIG. 9 ) are defined on the outer peripheral surface 751 of the lower portion 75 when viewed from below. Point P1 is the point where the first inter-plane distance (first inter-plane distance D1) between the outer peripheral surface 751 of the lower portion 75 and the outer peripheral surface 741 of the upper portion 74 is shortest. As shown in FIG. 9 , when proceeding counterclockwise from point P1 along the outer peripheral surface 751 of the lower portion 75, one passes through points P2 to P4 in order and returns to point P1. Here, point P2 is the end of the lower portion 75 in the positive direction of the X-axis. Point P3 is the point where the first inter-plane distance (first inter-plane distance D3) between the outer peripheral surface 751 of the lower portion 75 and the outer peripheral surface 741 of the upper portion 74 is longest. Point P4 is a relay point when proceeding counterclockwise from point P3 to point P1, and is, for example, the end of the lower portion 75 opposite point P2 (the negative side of the X-axis). 8 and 9, point P4 faces point P2 in the X-axis direction via shaft 314. Also, as shown in Fig. 9, sleeve 70 is fixed to recess 63 so that point P4 faces the deepest part of first groove 64 (the end in the negative direction of the X-axis) in the X-axis direction.

[0053] Here, the region from point P1 to point P2 on the outer peripheral surface 751 of the lower portion 75 is referred to as the first portion M11, the region from point P2 to point P3 as the first portion M12, the region from point P3 to point P4 as the second portion M2, and the region from point P4 to point P1 as the third portion M3. That is, as shown in FIG. 9 , the lower portion 75 has the first portion M11, the first portion M12, the second portion M2, and the third portion M3, and the third portion M3 connects the first portion M11 and the second portion M2. More specifically, the third portion M3 connects to the first portion M11 at point P1 and to the second portion M2 at point P4.

[0054] Furthermore, as described above, point P4 and the deepest part of the first groove portion 64 are opposed to each other in the X-axis direction, and therefore at least a part of the second portion M2 and at least a part of the third portion M3 are opposed to the first groove portion 64, as shown in FIG. 9.

[0055] The first inter-plane distance between the first portion M11 and the outer peripheral surface 741 of the upper portion 74 increases in one circumferential direction centered on the up-down direction. In this embodiment, the first inter-plane distance between the first portion M11 and the outer peripheral surface 741 of the upper portion 74 increases as one moves counterclockwise. Furthermore, the first inter-plane distance between the first portion M12 and the outer peripheral surface 741 of the upper portion 74 increases as one moves counterclockwise. As a result, the first inter-plane distance D3 is longer than the first inter-plane distance D1. Note that the first inter-plane distance D3 is preferably at least twice the first inter-plane distance D1, and more preferably at least five times the first inter-plane distance D1.

[0056] Furthermore, the first inter-plane distance between the second portion M2 and the outer peripheral surface 741 of the upper portion 74 is substantially constant along the circumferential direction. Therefore, the first inter-plane distance between the outer peripheral surface 751 of the lower portion 75 and the outer peripheral surface 741 of the upper portion 74 in the second portion M2 is longer than the first inter-plane distance between the outer peripheral surfaces 751 and 741 of the first portion M11. Furthermore, the first inter-plane distance between point P4 and the outer peripheral surface 741 of the upper portion 74 (first inter-plane distance D4) is longer than the first inter-plane distance between point P2 and the outer peripheral surface 741 of the upper portion 74 (first inter-plane distance D2) in a bottom view. Here, point P4 faces the deepest portion of the first groove portion 64 in the X-axis direction. This allows the distance between the first groove portion 64 and the outer peripheral surface 751 of the lower portion 75 to be longer, making it easier for the air bubble B1 in the space S1 to move to the groove portion 64.

[0057] In the third portion M3, the first inter-surface distance between the outer circumferential surface 751 of the lower portion 75 and the outer circumferential surface 741 of the upper portion 74 decreases counterclockwise.

[0058] (2.2) Operation The operation of blower 10 will be described below. When current is supplied to each coil 42 of blower 10, magnetic flux is generated in each tooth 411. Then, the action of the magnetic flux between teeth 411 and magnets 33 generates a circumferential torque between stator portion 40 and rotor portion 30. As a result, propeller 31 rotates around shaft 314, and airflow is generated by each blade 312. Bearing portion 50 stably supports rotating shaft 314.

[0059] 8 , the rotation of the shaft 314 causes the lubricating oil 90 in the recess 63 to flow circulating through the space S2 between the sleeve 70 and the shaft 314, the depression 631, the second groove 65, the space S1, the first groove 64, and the space S3 between the ridge 816 and the sleeve 70. Here, the space S1 is the space between the outer circumferential surface 751 of the lower portion 75 of the sleeve 70 and the outer circumferential surface 741 of the upper portion 74 of the sleeve 70, as described above.

[0060] In addition to the above-described flow, the lubricating oil 90 in the space S1 moves in the circumferential direction within the space S1 as shown in Fig. 9. The circumferential movement of the lubricating oil 90 in the space S1 will be described below.

[0061] The first inter-surface distance between the first portion M11 and the outer peripheral surface 741 of the upper portion 74, and the first inter-surface distance between the first portion M12 and the outer peripheral surface 741, decrease in the clockwise direction. This causes capillary action, causing the lubricating oil 90 to move clockwise within the space S1. Accordingly, the bubbles B1 generated within the lubricating oil 90 move counterclockwise within the space S1. In this embodiment, the first portion M11, the first portion M12, the second portion M2, and the third portion M3 are all curved when viewed from the top-bottom direction. Furthermore, the first portion M11 and the first portion M12 are smoothly connected at point P2. Furthermore, the first portion M12 and the second portion M2 are smoothly connected at point P3. This facilitates the lubricating oil 90 to move clockwise within the space S1, and the bubbles B1 to move counterclockwise within the space S1.

[0062] In the third portion M3, the first inter-surface distance between the outer peripheral surface 751 of the lower portion 75 and the outer peripheral surface 741 of the upper portion 74 becomes shorter in the counterclockwise direction, and therefore, counterclockwise movement of the bubble B1 is suppressed in the third portion M3. The bubble B1 that reaches the third portion M3 moves upward through the first groove portion 64. The bubble B1 that reaches the upper end of the first groove portion 64 is discharged to the outside of the recess 63 through the vent 814 of the first cap 81 (see FIG. 8 ).

[0063] (3) Modifications The above embodiment is merely one of various embodiments of the present disclosure. The above embodiment can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Modifications of the embodiment are listed below. The above embodiment and the modifications described below can be applied in appropriate combinations.

[0064] Modifications of the above embodiment are listed below. In the modifications described below, components common to the above embodiment are given the same reference numerals, and descriptions thereof will be omitted.

[0065] 10 and 11 , the upper portion 74 of the sleeve 70 may have an inclined portion 742. As shown in FIG. 11 , the inclined portion 742 is provided at the lower end of the upper portion 74 at a position facing the first groove portion 64 when viewed in the up-down direction. Furthermore, as shown in FIG. 10 , the distance between the inclined portion 742 and the housing 60 (the inner circumferential surface 630 of the recess 63) increases downward. This makes it easier for the air bubble B1 that moves counterclockwise within the space S1 and reaches the third portion M3 to move along the inclined portion 742 to the first groove portion 64.

[0066] In the above embodiment, the first part M11, the first part M12, the second part M2, and the third part M3 are all composed of curves when viewed from the top and bottom, but at least a portion of the first part M11, the first part M12, the second part M2, and the third part M3 may be composed of straight lines.

[0067] (Embodiment 2) (1) Overview An overview of the fan 10 (10a) of embodiment 2 will be described below with reference to Fig. 1 and Figs. 12 to 14. Note that the same components as those of embodiment 1 are denoted by the same reference numerals and their description will be omitted. In addition, the external appearance of the fan 10a is the same as that of the fan 10 of embodiment 1, and therefore will be described with reference to Fig. 1.

[0068] The blower 10 a includes a housing 60 a , a sleeve 70 a , a shaft 314 , a propeller 31 , and lubricating oil 90 .

[0069] The housing 60a has a recess 63a that opens upward.

[0070] The sleeve 70a has a through-hole 71. The sleeve 70a is disposed in the recess 63a.

[0071] The shaft 314 passes through the through-hole 71 .

[0072] The propeller 31 is connected to the upper end of the shaft 314 .

[0073] The lubricating oil 90 is contained in the recess 63a.

[0074] The housing 60 also has an upper portion 66 and a lower portion 67 located below the upper portion 66 .

[0075] The lubricating oil 90 is filled in the recess 63 a up to a position above the lower portion 67 .

[0076] At least a portion of the inner circumferential surface 671 of the lower portion 67 is located more inward than the inner circumferential surface 661 of the upper portion 66 when viewed from above.

[0077] When viewed from above, the distance between the inner circumferential surface 671 of the lower portion 67 and the inner circumferential surface 661 of the upper portion 66 (hereinafter referred to as the second inter-surface distance) becomes shorter along the circumferential direction of the inner circumferential surface 661 .

[0078] Here, the "circumferential direction of the inner circumferential surface 661" refers to the rotation direction of the propeller 31. In other words, the "circumferential direction of the inner circumferential surface 661" can be rephrased as the circumferential direction centered on the central axis A1 (see FIG. 14 ) of the shaft 314.

[0079] In this embodiment, the "second inter-surface distance" is the distance between a third point and a fourth point defined below. The third point is an arbitrary point on the "inner circumferential surface 671 of the lower portion 67." The fourth point is the intersection of a line passing through the third point and the central axis A1 of the shaft 314 and the "inner circumferential surface 661 of the upper portion 66" when viewed from the top-bottom direction.

[0080] According to the above configuration, for example, the second inter-surface distance decreases in one circumferential direction of the inner circumferential surface 661 (counterclockwise in FIG. 14 ). As a result, the distance between at least a portion of the inner circumferential surface 671 of the lower portion 67 and the outer circumferential surface 751a of the sleeve 70a (hereinafter referred to as the third inter-surface distance) increases in the counterclockwise direction. In other words, the third inter-surface distance decreases in the clockwise direction. In this embodiment, the "third inter-surface distance" is the distance between a fifth point and a sixth point, as defined below. The fifth point is an arbitrary point on the "inner circumferential surface 671 of the lower portion 67." The sixth point is the intersection of a line passing through the fifth point and the central axis A1 of the shaft 314 and the "outer circumferential surface 751a of the sleeve 70a" when viewed from the top-bottom direction.

[0081] Because the third inter-surface distance becomes shorter in the clockwise direction, capillary action causes the lubricating oil 90 to move clockwise within the space S1a between the inner circumferential surface 671 of the lower portion 67 and the outer circumferential surface 751a of the sleeve 70a. Accordingly, air bubbles B1 (see FIG. 14) generated within the lubricating oil 90 move counterclockwise within the space S1a. This prevents the air bubbles B1 from stagnating within the recess 63a, making it easier for the air bubbles B1 to be discharged to the outside of the recess 63a.

[0082] (2) Details The blower 10a according to this embodiment will be described in detail with reference to the drawings.

[0083] (2.1) Configuration First, the configuration of the blower 10a according to the embodiment will be described.

[0084] The blower 10a has a bearing portion 50a that is different from the bearing portion 50 of the blower 10 of embodiment 1. The configuration of the blower 10a other than the bearing portion 50a is the same as that of the blower 10, and therefore detailed description thereof will be omitted here.

[0085] The bearing 50a will be described in detail below. The bearing 50a is a portion that rotatably supports the shaft 314, the upper end of which is connected to the propeller 31. FIG. 12 is a perspective view of the bearing 50a and the shaft 314 according to the embodiment. FIG. 13 is a cross-sectional view taken along the XZ plane including the Y3-Y3 line in FIG. 12. The XZ plane including the Y3-Y3 line passes through the center line of the shaft 314. As shown in FIGS. 12 and 13, the bearing 50a has a housing 60a, a sleeve 70a, and a cap portion 80.

[0086] The housing 60a accommodates a portion of the shaft 314, the sleeve 70a, and the cap portion 80. As shown in FIGS. 12 and 13 , the housing 60a has a disk-shaped base 61a and a cylindrical tube portion 62a that protrudes upward from the base 61a. The tube portion 62a is open at the top and has a bottom at the bottom. The interior of the tube portion 62a forms a cylindrical recess 63a (see FIG. 13 ) that also has an opening at the top. Lubricating oil 90 is contained within the recess 63a. A groove (first groove) 64a extending from the top to the bottom along the Z-axis is formed on the inner circumferential surface 630a of the recess 63a at the end in the negative direction of the X-axis. The first groove 64a is recessed outward (in the negative direction of the X-axis) from the inner circumferential surface 630a of the recess 63a.

[0087] 13, a circular recess 631a is formed in the center of the bottom surface of the recess 63a. A receiving plate 632 for receiving the tip of the shaft 314 is disposed in the recess 631a.

[0088] A second groove 65a is formed on the bottom surface of the recess 63a, extending along the X-axis direction and connecting the first groove 64a and the recess 631a.

[0089] 13 and 14, the housing 60a has an upper portion 66 and a lower portion 67 located below the upper portion 66. Here, Fig. 14 is a cross-sectional view taken along the XY plane including the line Z2-Z2 in Fig. 12 as viewed from below. In the following description, "viewed from the vertical direction" refers to both a view from above and a view from below.

[0090] The upper portion 66 is cylindrical, and the inner diameter of the upper portion 66 is slightly smaller than the outer diameter of the sleeve 70a. Therefore, by press-fitting the sleeve 70a into the housing 60a (recess 63a), the sleeve 70a is fixed in a non-rotatable state relative to the recess 63a. In this state, a portion of the circumferential surface 630a (inner circumferential surface 661 of the upper portion 66) is in contact with the outer circumferential surface 741a of the sleeve 70a.

[0091] At least a portion of the inner circumferential surface 671 of the lower portion 67 is located more inward than the inner circumferential surface 661 of the upper portion 66 when viewed from the vertical direction. In this embodiment, the inner circumferential surface 671 of the lower portion 67 is located more inward than the inner circumferential surface 661 of the upper portion 66 around the entire circumferential circumference centered in the vertical direction when viewed from the vertical direction. In other words, when the sleeve 70a is fixed to the recess 63a, the inner circumferential surface 671 of the lower portion 67 faces the outer circumferential surface 751a of the sleeve 70a across a space S1a. Here, the lubricating oil 90 is filled in the recess 63a up to a position above the lower portion 67. This allows the lubricating oil 90 to be stored in the space S1a.

[0092] The shape of the lower portion 67 of the housing 60a will be described in more detail below.

[0093] To explain the shape of the lower portion 67, multiple points P1a to P5a are defined on the inner circumferential surface 671 of the lower portion 67 when viewed from below. Point P1a is the point where the second inter-surface distance (second inter-surface distance D1a) between the inner circumferential surface 671 of the lower portion 67 and the inner circumferential surface 661 of the upper portion 66 is longest. As shown in FIG. 14 , when traveling counterclockwise from point P1a along the inner circumferential surface 671 of the lower portion 67, one passes through points P2a to P4a in order and returns to point P1a. Here, point P2a is the end of the lower portion 67 in the positive direction of the X axis. Point P3a is the point where the second inter-surface distance between the inner circumferential surface 671 of the lower portion 67 and the inner circumferential surface 661 of the upper portion 66 becomes approximately zero. Point P4a is a relay point when traveling counterclockwise from point P3a to point P1a, and is, for example, the end of the lower portion 67 opposite point P2a (the negative side of the X axis). Point P4a overlaps with the deepest portion of first groove portion 64a (the end portion in the negative X-axis direction). In other words, first groove portion 64a is provided in a predetermined range in the circumferential direction around point P4a on inner circumferential surface 671.

[0094] 14, point P4a faces point P2a in the X-axis direction via shaft 314. Point P5a is a relay point when proceeding counterclockwise from point P4a to point P1a.

[0095] Here, the region on the inner circumferential surface 671 of the lower portion 67 from point P1a to point P2a is referred to as the first portion M11a, the region from point P2a to point P3a as the first portion M12a, the region from point P3a to point P4a as the second portion M2a, and the region from point P4a to point P1a as the third portion M3a. That is, as shown in FIG. 14 , the lower portion 67 has the first portion M11a, the first portion M12a, the second portion M2a, and the third portion M3a, and the third portion M3a connects the first portion M11a and the second portion M2a. More specifically, the third portion M3a connects to the first portion M11a at point P1a and to the second portion M2a at point P4a.

[0096] As described above, the first groove portion 64a is provided in a predetermined range in the circumferential direction around the point P4a on the inner circumferential surface 671. Therefore, the first groove portion 64a is provided in at least a part of the second portion M2a and at least a part of the third portion M3a.

[0097] The second inter-surface distance between the first portion M11a and the inner circumferential surface 661 of the upper portion 66 decreases as one moves counterclockwise. Also, the second inter-surface distance between the first portion M12a and the inner circumferential surface 661 of the upper portion 66 decreases as one moves counterclockwise.

[0098] Furthermore, the second inter-plane distance between the second portion M2a and the inner circumferential surface 661 of the upper portion 66 is substantially constant along the circumferential direction. In this embodiment, the second inter-plane distance between the second portion M2a and the inner circumferential surface 661 of the upper portion 66 is substantially zero. Therefore, the second inter-plane distance between the inner circumferential surface 671 of the lower portion 67 and the inner circumferential surface 661 of the upper portion 66 in the second portion M2a is shorter than the second inter-plane distance between the inner circumferential surface 671 and the inner circumferential surface 661 in the first portion M11a. Furthermore, the second inter-plane distance between point P4a and the inner circumferential surface 661 of the upper portion 66 is substantially zero, and in a bottom view, the second inter-plane distance between point P4a and the inner circumferential surface 661 of the upper portion 66 is shorter than the second inter-plane distance (second inter-plane distance D2a) between point P2a and the inner circumferential surface 661 of the upper portion 66. That is, the third inter-plane distance between point P4a and the outer peripheral surface 751a of the sleeve 70a is longer than the third inter-plane distance between point P2a and the outer peripheral surface 751a in a bottom view. Here, as described above, the first groove portion 64a is provided in the inner peripheral surface 671 within a predetermined range in the circumferential direction centered on point P4a. This increases the distance between the first groove portion 64a and the outer peripheral surface 751a of the sleeve 70a, making it easier for the air bubble B1 in the space S1a to move to the first groove portion 64a.

[0099] Furthermore, in at least a part of the third portion M3a, the second inter-surface distance between the inner circumferential surface 671 of the lower portion 67 and the inner circumferential surface 661 of the upper portion 66 increases counterclockwise. More specifically, in the region of the third portion M3a from point P5a to point P1a, the second inter-surface distance increases counterclockwise.

[0100] The sleeve 70a is disposed in the recess 63a. As shown in Figures 13 and 14, the sleeve 70a is a cylindrical member having a through-hole 71 formed in the center thereof and extending in the Z-axis direction.

[0101] 13, the sleeve 70a has an upper portion 74a and a lower portion 75a located below the upper portion 74a. The upper portion 74a and the lower portion 75a are cylindrical and centered on the central axis A1 of the shaft 314. The outer diameter of the upper portion 74a is larger than the outer diameter of the lower portion 75a. The outer diameter of the lower portion 75a is set to a size such that it does not come into contact with the inner circumferential surface 671 of the lower portion 67 of the housing 60a.

[0102] Furthermore, the upper portion 74a of the sleeve 70a has an inclined portion 742a. ​​More specifically, the inclined portion 742a is provided at a position on the upper portion 74a facing the lower end of the upper portion 66 in the up-down direction. The inclined portion 742a is preferably provided at a position facing the first groove portion 64a when viewed in the up-down direction. In this embodiment, the inclined portion 742a is provided around the entire circumferential direction at a position facing the lower end of the upper portion 66 in the up-down direction. This allows the inclined portion 742a and the first groove portion 64a to face each other regardless of the circumferential orientation of the sleeve 70a. As shown in FIG. 13 , the distance between the inclined portion 742a and the housing 60a (the inner circumferential surface 630a of the recess 63a) increases downward.

[0103] (2.2) Operation The operation of the fan 10a will be described below. Note that a description of the operation common to the fan 10 will be omitted.

[0104] 14, the rotation of the shaft 314 causes the lubricating oil 90 in the space S1a to move in the circumferential direction within the space S1a. The circumferential movement of the lubricating oil 90 in the space S1a will be described below.

[0105] The second inter-surface distance between the first portion M11a and the inner circumferential surface 661 of the upper portion 66 and the second inter-surface distance between the first portion M12a and the inner circumferential surface 661 decrease in the counterclockwise direction. Here, the distance (the radial distance around the central axis A1) between the inner circumferential surface 661 of the upper portion 66, excluding the first groove portion 64a, and the outer circumferential surface 751a of the sleeve 70a, is constant along the circumferential direction. That is, the first portions M11a and M12a approach the outer circumferential surface 751a of the sleeve 70a as they move clockwise. As a result, the third inter-surface distance between the first portions M11a and M12a and the outer circumferential surface 751a of the sleeve 70a decreases in the clockwise direction. This causes capillary action, causing the lubricating oil 90 to move clockwise within the space S1a. Accordingly, bubbles B1 generated in the lubricating oil 90 move counterclockwise within the space S1a. In this embodiment, the first portion M11a, the first portion M12a, the second portion M2a, and the third portion M3a are all formed by curves when viewed from the top-bottom direction. The first portion M11a and the first portion M12a are smoothly connected at point P2a. The first portion M12a and the second portion M2a are smoothly connected at point P3a. This facilitates clockwise movement of the lubricating oil 90 within the space S1a, and facilitates counterclockwise movement of the air bubbles B1 within the space S1a. At least some of the first portion M11a, the first portion M12a, the second portion M2a, and the third portion M3a may be formed by straight lines.

[0106] In the third portion M3a, the second inter-surface distance between the inner circumferential surface 671 of the lower portion 67 and the inner circumferential surface 661 of the upper portion 66 increases counterclockwise. That is, in the third portion M3a, the third inter-surface distance between the inner circumferential surface 671 of the lower portion 67 and the outer circumferential surface 751a of the sleeve 70a decreases counterclockwise. Therefore, counterclockwise movement of the bubble B1 is suppressed in the third portion M3a. The bubble B1 that reaches the third portion M3a moves upward through the first groove 64a. Because the sleeve 70a has the inclined portion 742a, the bubble B1 that moves counterclockwise through the space S1a and reaches the third portion M3a is more likely to move along the inclined portion 742a to the first groove 64a.

[0107] The air bubbles B1 that reach the upper end of the first groove portion 64a are discharged to the outside of the recess 63a through the vent hole 814 of the first cap 81.

[0108] (Summary) As described above, the blower (10) of the first aspect includes a housing (60), a sleeve (70), a shaft (314), a propeller (31), and lubricating oil (90). The housing (60) has a recess (63) that opens upward. The sleeve (70) has a through-hole (71). The sleeve (70) is disposed within the recess (63). The shaft (314) passes through the through-hole (71). The propeller (31) is connected to the upper end of the shaft (314). The lubricating oil (90) is accommodated within the recess (63). The sleeve (70) also has an upper portion (74) and a lower portion (75) located below the upper portion (74). The lubricating oil (90) is filled within the recess (63) up to a level above the lower portion (75). When viewed from below, the outer peripheral surface (751) of the lower portion (75) is located inside the outer peripheral surface (741) of the upper portion (74). When viewed from below, the distance between the outer peripheral surface (751) of the lower portion (75) and the outer peripheral surface (741) of the upper portion (74) is at least partially elongated along the circumferential direction of the outer peripheral surface (741).

[0109] According to this embodiment, the bubbles (B1) are prevented from stagnating in the recess (63), and the bubbles (B1) are easily discharged to the outside of the recess (63).

[0110] In the blower (10) of the second aspect, in the first aspect, the outer peripheral surface (751) of the lower part (75) of the sleeve (70) is located inside the outer peripheral surface (741) of the upper part (74) over the entire circumference when viewed from the top-bottom direction.

[0111] According to this embodiment, the bubbles (B1) are more easily discharged to the outside of the recess (63).

[0112] In the blower (10) of the third aspect, in the first or second aspect, the recess (63) of the housing (60) has a groove (64) recessed outward. The sleeve (70) is disposed in the recess (63) so that the outer peripheral surface (751) of the lower part (75) faces the groove (64).

[0113] According to this embodiment, the bubbles (B1) are easily discharged to the outside of the recess (63) through the groove (64).

[0114] In the blower (10) of the fourth aspect, in the third aspect, the lower part (75) of the sleeve (70) has a first side part (P4) facing the groove part (64) and a second side part (P2) facing the first side part (P4) across the shaft (314). When viewed from below, the distance between the outer peripheral surface (751) of the lower part (75) and the outer peripheral surface (741) of the upper part (74) at the first side part (P4) is longer than the distance between the outer peripheral surface (751) of the lower part (75) and the outer peripheral surface (741) of the upper part (74) at the second side part (P2).

[0115] According to this embodiment, the bubbles (B1) can easily move to the grooves (64).

[0116] In the blower (10) of the fifth aspect, in the third or fourth aspect, the lower part (75) of the sleeve (70) has a first part (M11), a second part (M2) in which the distance between the outer peripheral surface (751) of the lower part (75) and the outer peripheral surface (741) of the upper part (74) is longer than that of the first part (M11) when viewed from below, and a third part (M3) connecting the first part (M11) and the second part (M2). In at least a part of the third part (M3), the distance between the outer peripheral surface (751) of the lower part (75) and the outer peripheral surface (741) of the upper part (74) when viewed from below becomes shorter along the circumferential direction centered on the up-down direction. The third part (M3) faces the groove part (64).

[0117] According to this aspect, the movement of the bubbles (B1) in one circumferential direction is suppressed in the third portion (M3), which makes it easier for the bubbles (B1) that reach the third portion (M3) to move upward through the groove portion (64).

[0118] In the blower (10) of the sixth aspect, in any one of the third to fifth aspects, the upper portion (74) of the sleeve (70) has a sloped portion (742) at the lower end of the upper portion (74). The sloped portion (742) faces the groove portion (64) when viewed from below. When viewed from below, the distance between the sloped portion (742) and the housing (60) increases downward.

[0119] According to this aspect, the air bubble (B1) that moves within the space (S1) in one circumferential direction centered on the vertical direction and reaches the third portion (M3) is more likely to move along the inclined portion (742) to the groove portion (64).

[0120] A blower (10a) of a seventh aspect includes a housing (60a), a sleeve (70a), a shaft (314), a propeller (31), and lubricating oil (90). The housing (60a) has a recess (63a) that opens upward. The sleeve (70a) has a through-hole (71). The sleeve (70a) is disposed within the recess (63a). The shaft (314) passes through the through-hole (71). The propeller (31) is connected to the upper end of the shaft (314). The lubricating oil (90) is accommodated within the recess (63a). The housing (60a) has an upper portion (66) and a lower portion (67) located below the upper portion (66). The lubricating oil (90) is filled within the recess (63a) up to a level above the lower portion (67). When viewed from above, the inner peripheral surface (671) of the lower portion (67) is located inside the inner peripheral surface (661) of the upper portion (66). When viewed from above, the distance between the inner peripheral surface (671) of the lower portion (67) and the inner peripheral surface (661) of the upper portion (66) becomes shorter along the circumferential direction of the inner peripheral surface (661) of the upper portion (66).

[0121] According to this embodiment, the bubbles (B1) are prevented from stagnating in the recesses (63a), and the bubbles (B1) are easily discharged to the outside of the recesses (63a).

[0122] In the blower (10a) of the eighth aspect, in the seventh aspect, the inner surface (671) of the lower part (67) of the housing (60a) is located inside the inner surface (661) of the upper part (66) around the entire circumference when viewed from above.

[0123] According to this embodiment, the bubbles (B1) are more easily discharged to the outside of the recess (63a).

[0124] In the blower (10a) of the ninth aspect, in the seventh and eighth aspects, the recess (63a) of the housing (60a) has a groove (64a) recessed outward.

[0125] According to this embodiment, the bubbles (B1) are easily discharged to the outside of the recess (63a) through the groove (64a).

[0126] In the blower (10a) of the tenth aspect, in the ninth aspect, the lower part (67) of the housing (60a) has a first side part (P4a) in which the groove part (64a) is provided, and a second side part (P2a) facing the first side part (P4a) across the shaft (314). When viewed from above, the distance between an inner peripheral surface (671) of the lower part (67) and an inner peripheral surface (661) of the upper part (66) at the first side part (P4a) is shorter than the distance between the inner peripheral surface (671) of the lower part (67) and the inner peripheral surface (661) of the upper part (66) at the second side part (P2a).

[0127] According to this embodiment, the bubbles (B1) can easily move to the grooves (64a).

[0128] In the blower (10a) of the eleventh aspect, in the ninth or tenth aspect, the lower part (67) has a first portion (M11a), a second portion (M2a) in which the distance between the inner peripheral surface (671) of the lower part (67) and the inner peripheral surface (661) of the upper part (66) is shorter than that of the first portion (M11a), as viewed from above, and a third portion (M3a) connecting the first portion (M11a) and the second portion (M2a). In at least a part of the third portion (M3a), the distance between the inner peripheral surface (671) of the lower part (67) and the inner peripheral surface (661) of the upper part (66) increases in the circumferential direction centered on the up-down direction, as viewed from above. A groove portion (64a) is provided in the third portion (M3a).

[0129] According to this aspect, the movement of the bubbles (B1) in one circumferential direction is suppressed in the third portion (M3a), which makes it easier for the bubbles (B1) that reach the third portion (M3a) to move upward through the groove portion (64a).

[0130] In the blower (10a) of a twelfth aspect, in any one of the ninth to eleventh aspects, the sleeve (70a) has an inclined portion (742a) at a position facing the lower end of the upper portion (66). The inclined portion (742a) faces the groove portion (64a) when viewed from below. When viewed from below, the distance between the inclined portion (742a) and the housing (60a) increases downward.

[0131] According to this aspect, the bubble (B1) that moves within the space (S1a) in one circumferential direction centered on the vertical direction and reaches the third portion (M3a) is more likely to move along the inclined portion (742a) to the groove portion (64a).

[0132] In the blower (10a) of a thirteenth aspect, in any one of the ninth to eleventh aspects, the sleeve (70a) has an inclined portion (742a) provided around the entire circumferential direction at a position facing the lower end of the upper portion (66). When viewed from above, the distance between the inclined portion (742a) and the housing (60a) increases downward.

[0133] According to this aspect, the bubble (B1) that has traveled through the space (S1a) in one circumferential direction centered on the vertical direction and reached the third portion (M3a) is more likely to travel along the inclined portion (742a) to the groove portion (64a). Furthermore, the inclined portion (742a) and the groove portion (64a) can be made to face each other regardless of the circumferential direction of the sleeve (70a).

[0134] The second to sixth aspects are not essential components of the blower (10) and may be omitted as appropriate. The eighth to thirteenth aspects are not essential components of the blower (10a) and may be omitted as appropriate.

[0135] 10 Blower 31 Propeller 60 Housing 63 Recess 64 Groove (first groove) 66 Upper part 67 Lower part 70 Sleeve 71 Through hole 74 Upper part 75 Lower part 90 Lubricating oil 314 Shaft 630 Inner peripheral surface 661 Inner peripheral surface 671 Inner peripheral surface 741 Outer peripheral surface 742 Inclined part 751 Outer peripheral surface 10a Blower 60a Housing 630a Inner peripheral surface 63a Recess 64a Groove (first groove) 70a Sleeve 742a Inclined part B1 Air bubble M11 First part M11a First part M2 Second part M2a Second part M3 Third part M3a Third part P2a Second side part P4a First side part S1 Space S1a Space

Claims

1. A blower comprising: a housing having a recess that opens upward; a sleeve having a through hole and disposed within the recess; a shaft that passes through the through hole; a propeller connected to the upper end of the shaft; and lubricating oil contained within the recess, wherein the sleeve has an upper part and a lower part located below the upper part, the lubricating oil is filled in the recess up to a position above the lower part, the outer peripheral surface of the lower part includes a first outer peripheral surface, the first outer peripheral surface of the lower part is located more inward than the outer peripheral surface of the upper part when viewed from below, and at least a portion of the distance between the first outer peripheral surface of the lower part and the outer peripheral surface of the upper part is longer circumferentially along the outer peripheral surface of the upper part when viewed from below.

2. A blower according to claim 1, wherein the outer peripheral surface of the lower part of the sleeve is located inside the outer peripheral surface of the upper part along the entire circumferential direction of the outer peripheral surface of the lower part when viewed from below.

3. A blower according to claim 1 or 2, wherein the recess of the housing has a groove recessed outward, and the sleeve is disposed within the recess so that the outer circumferential surface of the lower part faces the groove.

4. A blower as described in claim 3, wherein the lower part of the sleeve has a first side part facing the groove part and a second side part facing the first side part across the shaft, and when viewed from below, the distance between the outer circumferential surface of the lower part at the first side part and the outer circumferential surface of the upper part is longer than the distance between the outer circumferential surface of the lower part at the second side part and the outer circumferential surface of the upper part.

5. A blower as described in claim 3 or 4, wherein the lower part of the sleeve has: a first part; a second part in which, when viewed from below, the distance between the outer circumferential surface of the lower part and the outer circumferential surface of the upper part is longer than that of the first part; and a third part connecting the first part and the second part, wherein, in at least a part of the third part, when viewed from below, the distance between the outer circumferential surface of the lower part and the outer circumferential surface of the upper part is shorter along the circumferential direction of the outer circumferential surface, and the third part faces the groove portion.

6. A blower according to any one of claims 3 to 5, wherein the upper portion of the sleeve has a sloped portion at a lower end thereof, the sloped portion faces the groove portion when viewed from below, and the distance between the sloped portion and the housing increases downward when viewed from below.

7. A blower comprising: a housing having a recess that opens upward; a sleeve having a through hole and disposed within the recess; a shaft that passes through the through hole; a propeller connected to the upper end of the shaft; and lubricating oil contained within the recess, wherein the housing has an upper part and a lower part located below the upper part, the lubricating oil is filled in the recess up to a position above the lower part, the inner circumferential surface of the lower part includes a first inner circumferential surface, the first inner circumferential surface of the lower part is located more inward than the inner circumferential surface of the upper part when viewed from above, and at least a portion of the distance between the first inner circumferential surface of the lower part and the inner circumferential surface of the upper part is shortened along the circumferential direction of the inner circumferential surface of the upper part when viewed from above.

8. The blower according to claim 7, wherein the inner circumferential surface of the lower part of the housing is located more inward than the inner circumferential surface of the upper part along the entire circumferential direction of the inner circumferential surface of the lower part when viewed from above.

9. The blower according to claim 7 or 8, wherein the recess of the housing has a groove recessed outward.

10. A blower as described in claim 9, wherein the lower part of the housing has a first side part in which the groove part is provided, and a second side part that faces the first side part via the shaft, and when viewed from above, the distance between the inner peripheral surface of the lower part at the first side part and the inner peripheral surface of the upper part is shorter than the distance between the inner peripheral surface of the lower part at the second side part and the inner peripheral surface of the upper part.

11. A blower as described in claim 9 or 10, wherein the lower part of the housing has: a first part; a second part in which, when viewed from above, the distance between the inner circumferential surface of the lower part and the inner circumferential surface of the upper part is shorter than that of the first part; and a third part connecting the first part and the second part; and in at least part of the third part, the distance between the inner circumferential surface of the lower part and the inner circumferential surface of the upper part is longer in the circumferential direction when viewed from above, and the third part is provided with the groove portion.

12. A blower as claimed in any one of claims 9 to 11, wherein the sleeve has an inclined portion at a position facing the lower end of the upper part of the housing, the inclined portion facing the groove portion when viewed from below, and the distance between the inclined portion and the housing when viewed from below increases downward.

13. A blower as claimed in any one of claims 9 to 11, wherein the sleeve has an inclined portion at a position opposite the lower end of the upper part of the housing, the inclined portion being provided around the entire circumference in the circumferential direction, and the distance between the inclined portion and the housing increases downward when viewed from above.

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