Axial flow fan

Abstract

To provide an axial flow fan capable of improving assembly workability while improving rigidity.SOLUTION: An axial fan includes a housing, an upper side motor, and a lower side motor. The housing is formed by connecting an upper side housing and a lower side housing. A lower side peripheral wall of the lower side housing includes a plurality of first engagement parts and a plurality of lower side protrusion pieces. The first engagement part is arranged on the outer surface in the radial direction. The lower side protrusion piece protrudes to the upper side in the axial direction from the upper surface in the axial direction opposing the first engagement part and the axial direction. An upper side peripheral wall of the upper side housing includes a plurality of upper side engagement claws, and a plurality of upper side notch grooves. The upper side engagement claw extends from a lower surface in the axial direction to the lower side in the axial direction, and has a second engagement part engaged with the first engagement part at a lower end part. The upper side notch groove is notched from the lower surface in the axial direction to the upper side in the axial direction on the inside in the radial direction of the upper side engagement claw. At least part of the lower side protrusion piece is positioned in the upper side notch groove.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an axial fan. [Background technology]

[0002] In a conventional axial flow fan, an upper housing and a lower housing are connected to form a housing surrounding a central axis. The upper housing houses an upper motor that rotates an upper impeller about the central axis. The lower housing houses a lower motor that rotates a lower impeller about the central axis.

[0003] The upper housing has a plurality of upper engagement claws extending axially downward, and the upper engagement claws engage with the lower housing (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] China Patent Application Publication No. 107781225 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in conventional axial fans, when the rigidity of the housing is increased, the upper engaging claws become less flexible, which causes a problem of reduced workability in assembling the upper and lower housings.

[0006] An object of the present invention is to provide an axial flow fan that can improve the rigidity and ease of assembly. [Means for solving the problem]

[0007] An exemplary axial flow fan of the present invention includes a housing, an upper motor, and a lower motor. The housing is formed by connecting the upper housing and the lower housing. The upper housing surrounds a central axis extending vertically and is disposed at an upper axial position. The lower housing is disposed at a lower axial position. The upper motor is accommodated in the upper housing and rotates the upper impeller about the central axis. The lower motor is accommodated in the lower housing and rotates the lower impeller about the central axis. The upper housing has a cylindrical upper peripheral wall that covers the upper impeller and the upper motor from the radial outside. The lower housing has a cylindrical lower peripheral wall that covers the lower impeller and the lower motor from the radial outside. The lower peripheral wall has a plurality of first engagement portions and a plurality of lower protruding pieces. The first engagement portions are disposed on the radial outer surface. The lower protruding piece protrudes axially upward from the axial upper surface, axially opposite the first engagement portion. The upper peripheral wall has a plurality of upper engagement claws and upper notch grooves. The upper engagement claws have a second engagement portion that extends axially downward from the axial lower surface and engages with the lower engagement male portion at its lower end. The upper notch groove is cut out axially upward from the axial lower surface radially inside the upper engagement claw. At least a portion of the lower protruding piece is positioned within the upper notch groove. Effect of the Invention

[0008] According to an exemplary embodiment of the present invention, it is possible to provide an axial flow fan that can improve the rigidity and the ease of assembly. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is an overall perspective view of an axial flow fan according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an exploded perspective view of the axial flow fan according to the embodiment of the present invention. [Diagram 3] FIG. 3 is a vertical cross-sectional view of the axial flow fan according to the embodiment of the present invention. [Figure 4] FIG. 4 is a perspective view of an upper housing of the axial fan according to the embodiment of the present invention. [Diagram 5]FIG. 5 is a perspective view of a lower housing of the axial flow fan according to the embodiment of the present invention. [Figure 6] FIG. 6 is an enlarged perspective view of a portion of the housing of the axial fan according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an exemplary embodiment of the present invention will be described in detail with reference to the drawings. In this specification, the direction in which the central axis of the axial fan extends is simply called the "axial direction", the direction perpendicular to the central axis of the axial fan is simply called the "radial direction", and the direction along the arc centered on the central axis of the axial fan is simply called the "circumferential direction". In this specification, for convenience of explanation, the axial direction is defined as the up-down direction, and the up-down direction in FIG. 3 is defined as the up-down direction of the axial fan, and the shape and positional relationship of each part will be described. The "upper side" of the axial fan is the "intake side", and the "lower side" is the "exhaust side". Note that this definition of the up-down direction does not limit the orientation and positional relationship of the axial fan when it is used. In this specification, a cross section parallel to the axial direction is referred to as a "longitudinal cross section". In addition, the term "parallel" used in this specification does not mean parallel in the strict sense, but includes approximately parallel.

[0011] <1. Overall structure of axial flow fan> Fig. 1 is an overall perspective view of one example of an axial fan 1 according to an embodiment of the present invention, and Fig. 2 is an exploded perspective view of the axial fan 1. Fig. 3 is a vertical cross-sectional view of the axial fan. The axial fan 1 is formed by connecting an upper fan 4 and a lower fan 5.

[0012] The upper fan 4 has an upper housing 41, an upper impeller 42, an upper motor 43, and an upper circuit board 44. The lower fan 5 has a lower housing 51, a lower impeller 52, a lower motor 53, and a lower circuit board 54.

[0013] The upper housing 41 and the lower housing 51 are connected in the axial direction to form the housing 2. The connection structure between the upper housing 41 and the lower housing 51 will be described in detail later. The housing 2 has an air flow path 3 therein. The air flow path 3 extends along the central axis C inside the housing 2. The air flow path 3 has an intake port 31 at an upper end and an exhaust port 32 at a lower end.

[0014] <1-1. Upper fan configuration> The upper housing 41 is a resin molded product, and accommodates therein the upper impeller 42, the upper motor 43, and the upper circuit board 44. The upper housing 41 has an upper motor base portion 411 and an upper peripheral wall 412.

[0015] The upper motor base portion 411 has a base portion 4111 , a bearing holder 4112 , and an upper support portion 4113 .

[0016] The base 4111 is disposed axially below the upper motor 43, and has a disk shape extending radially about a central axis C. The bearing holder 4112 protrudes axially upward from an upper surface of the base 4111, and has a cylindrical shape centered on the central axis C.

[0017] The upper support portion 4113 extends radially outward from the radial outer surface of the base portion 4111 to connect the base portion 4111 and the upper peripheral wall 412. A plurality of upper support portions 4113 are arranged in the circumferential direction. Air flowing through the air-blowing passage 3 passes between adjacent upper support portions 4113.

[0018] The upper peripheral wall 412 is disposed radially outside the upper impeller 42. The upper peripheral wall 412 is cylindrical and extends vertically in the axial direction. That is, the upper peripheral wall 412 covers the upper impeller 42 and the upper motor 43 from the radial outside. The air flow passage 3 is disposed radially inside the upper peripheral wall 412. The air intake 31 is disposed at the axial upper end of the upper peripheral wall 412.

[0019] The upper impeller 42 is disposed radially inside the upper housing 41, and axially above and radially outside the upper motor 43. The upper impeller 42 is rotated around the central axis C by the upper motor 43. The upper impeller 42 has an upper impeller cup 421 and a plurality of upper blades 422.

[0020] The upper impeller cup 421 is fixed to the upper motor 43. The upper impeller cup 421 is a substantially cylindrical member having a lid on the axially upper side. The upper vanes 422 are arranged in the circumferential direction on the outer surface of the upper impeller cup 421.

[0021] The upper motor 43 is accommodated in the upper housing 41. The upper motor 43 is supported by the upper motor base portion 411. The upper motor 43 rotates the upper impeller 42 around the central axis C. The upper motor 43 has an upper shaft 431, an upper bearing 432, an upper stator 433, and an upper rotor 434.

[0022] The upper shaft 431 is disposed along the central axis C. The upper shaft 431 is made of a metal such as stainless steel, and is a columnar member extending up and down in the axial direction. The upper shaft 431 is supported by an upper bearing 432 so as to be rotatable around the central axis C.

[0023] The upper bearings 432 are arranged in at least one pair, one above and one below in the axial direction. The upper bearings 432 are held inside the bearing holder 4112. The upper bearings 432 are formed, for example, of ball bearings, but may also be formed of sleeve bearings or the like. The pair of upper bearings 432, one above and one below in the axial direction, support the upper shaft 431 rotatably around the central axis C with respect to the upper housing 41.

[0024] The upper stator 433 is fixed to the outer circumferential surface of the bearing holder 4112. The upper stator 433 has a stator core 4331, an insulator 4332, and a coil 4333.

[0025] Stator core 4331 is formed by stacking electromagnetic steel plates such as silicon steel plates one above the other. Insulator 4332 is made of insulating resin. Insulator 4332 is provided to surround the outer surface of stator core 4331. Coil 4333 is formed of a conductive wire wound around stator core 4331 via insulator 4332.

[0026] The upper rotor 434 is disposed axially above and radially outward of the upper stator 433. The upper rotor 434 rotates about a central axis C relative to the upper stator 433. The upper rotor 434 includes a rotor yoke 4341 and a magnet 4342.

[0027] Rotor yoke 4341 is made of a magnetic material and is a substantially cylindrical member having a cover on the axially upper side. Rotor yoke 4341 is fixed to upper shaft 431. Magnet 4342 is cylindrical and fixed to the inner circumferential surface of rotor yoke 4341. Magnet 4342 is disposed radially outside upper stator 433.

[0028] The upper circuit board 44 is disposed axially below the upper impeller 42 and the upper motor 43, and axially above the base portion 4111 of the upper motor base portion 411. The upper circuit board 44 is, for example, in the shape of a disk expanding in the radial direction about the central axis C. The upper circuit board 44 is electrically connected to the lead wire of the coil 4333. An electronic circuit for supplying a drive current to the coil 4333 is mounted on the upper circuit board 44.

[0029] In the upper fan 4 configured as described above, when a driving current is supplied to the coil 4333 of the upper motor 43 via the upper circuit board 44, a radial magnetic flux is generated in the stator core 4331. A magnetic field generated by the magnetic flux of the stator core 4331 and a magnetic field generated by the magnet 4342 act on each other, generating a torque in the circumferential direction of the upper rotor 434. This torque causes the upper rotor 434 and the upper impeller 42 to rotate about the central axis C. When the upper impeller 42 rotates, an airflow is generated by the multiple upper blades 422. That is, in the upper fan 4, an airflow is generated with the upper side as the intake side and the lower side as the exhaust side, and air can be blown.

[0030] <1-2. Configuration of the lower fan> The lower housing 51 is a resin molded product, and accommodates therein the lower impeller 52, the lower motor 53, and the lower circuit board 54. The lower housing 51 has a lower motor base portion 511 and a lower peripheral wall 512.

[0031] The lower motor base portion 511 has a base portion 5111 , a bearing holder 5112 , and a lower support portion 5113 .

[0032] The base 5111 is disposed axially above the lower motor 53, and has a disk shape extending radially about a central axis C. The bearing holder 5112 protrudes axially downward from the lower surface of the base 5111, and has a cylindrical shape centered on the central axis C.

[0033] The lower support portion 5113 extends radially outward from the radial outer surface of the base portion 5111 to connect the base portion 5111 and the lower peripheral wall 512. A plurality of lower support portions 5113 are arranged in the circumferential direction. Air flowing through the air-blowing passage 3 passes between adjacent lower support portions 5113.

[0034] The lower peripheral wall 512 is disposed radially outside the lower impeller 52. The lower peripheral wall 512 is cylindrical and extends vertically in the axial direction. That is, the lower peripheral wall 512 covers the lower impeller 52 and the lower motor 53 from the radial outside. The air flow passage 3 is disposed radially inside the upper and lower peripheral walls 512. An exhaust port 32 is disposed at the axial lower end of the lower peripheral wall 512.

[0035] The lower impeller 52 is disposed radially inside the lower housing 51, and axially below and radially outside the lower motor 53. The lower impeller 52 is rotated around the central axis C by the lower motor 53. The lower impeller 52 has a lower impeller cup 521 and a plurality of lower vanes 522.

[0036] The lower impeller cup 521 is fixed to the lower motor 53. The lower impeller cup 521 is a substantially cylindrical member having a lid on the axially lower side. The lower vanes 522 are arranged in the circumferential direction on the outer surface of the lower impeller cup 521.

[0037] The lower motor 53 is accommodated in the lower housing 51. The lower motor 53 is supported by a lower motor base portion 511. The lower motor 53 rotates the lower impeller 52 around a central axis C. The lower motor 53 has a lower shaft 531, a lower bearing 532, a lower stator 533, and a lower rotor 534.

[0038] The lower shaft 531 is disposed along the central axis C. The lower shaft 531 is made of a metal such as stainless steel, and is a columnar member extending up and down in the axial direction. The lower shaft 531 is supported by a lower bearing 532 so as to be rotatable around the central axis C.

[0039] The lower bearings 532 are arranged in at least one pair, one above and one below in the axial direction. The lower bearings 532 are held inside the bearing holder 5112. The lower bearings 532 are formed, for example, of ball bearings, but may also be formed of sleeve bearings or the like. The pair of lower bearings 532, one above and one below in the axial direction, support the lower shaft 531 rotatably around the central axis C with respect to the lower housing 51.

[0040] The lower stator 533 is fixed to the outer circumferential surface of the bearing holder 5112. The lower stator 533 includes a stator core 5331, an insulator 5332, and a coil 5333.

[0041] The stator core 5331 is formed by stacking electromagnetic steel plates, such as silicon steel plates, one above the other. The insulator 5332 is made of insulating resin. The insulator 5332 is provided to surround the outer surface of the stator core 5331. The coil 5333 is formed of a conducting wire wound around the stator core 5331 via the insulator 5332.

[0042] The lower rotor 534 is disposed axially below and radially outward of the lower stator 533. The lower rotor 534 rotates about a central axis C relative to the lower stator 533. The lower rotor 534 includes a rotor yoke 5341 and a magnet 5342.

[0043] The rotor yoke 5341 is made of a magnetic material and is a substantially cylindrical member having a cover on the axially lower side. The rotor yoke 5341 is fixed to the lower shaft 531. The magnet 5342 is cylindrical and fixed to the inner peripheral surface of the rotor yoke 5341. The magnet 5342 is disposed radially outside the lower stator 533.

[0044] The lower circuit board 54 is disposed axially above the lower impeller 52 and the lower motor 53, and axially below the base portion 5111 of the lower motor base portion 511. The lower circuit board 54 is, for example, in the shape of a disk extending radially about the central axis C. The lead wires of the coils 5333 are electrically connected to the lower circuit board 54. An electronic circuit for supplying a drive current to the coils 5333 is mounted on the lower circuit board 54.

[0045] In the lower fan 5 configured as described above, when a driving current is supplied to the coil 5333 of the lower motor 53 via the lower circuit board 54, a radial magnetic flux is generated in the stator core 5331. A magnetic field generated by the magnetic flux of the stator core 5331 and a magnetic field generated by the magnet 5342 act on each other, generating a torque in the circumferential direction of the lower rotor 534. This torque causes the lower rotor 534 and the lower impeller 52 to rotate about the central axis C. When the lower impeller 52 rotates, an airflow is generated by the multiple lower blades 522. That is, in the lower fan 5, an airflow is generated with the upper side as the intake side and the lower side as the exhaust side, and air can be blown.

[0046] <2.Detailed structure of the upper housing> 4 is a perspective view of the upper housing 41, showing the state when the upper housing 41 is viewed from the axially lower side. The upper peripheral wall 412 of the upper housing 41 has a pair of upper engagement claws 4121, upper cutout grooves 4122, upper engagement male portions (third engagement portions) 4123, upper protruding pieces 4124, upper recesses 4125, and upper protrusions 4126. The upper peripheral wall 412 also has an upper annular rib 4128.

[0047] The upper engagement claw 4121 extends axially downward from the axial lower surface 4120 of the upper peripheral wall 412 and has an upper engagement female portion (second engagement portion) 4121a at its lower end. In this embodiment, the upper engagement female portion 4121a is formed as a through hole that penetrates the upper engagement claw 4121 in the radial direction. Note that the upper engagement female portion 4121a is not limited to a through hole, and may be formed by forming a recess on the radial inner surface of the upper engagement claw 4121. The upper engagement claw 4121 is formed so that its circumferential width narrows toward the axially downward side.

[0048] The upper cutout groove 4122 is formed by cutting out the axially upper side from the axially lower surface 4120 on the radially inner side of the upper engagement claw 4121. In other words, the upper cutout groove 4122 has a concave shape that is concave in the axial direction. Both circumferential ends of the upper cutout groove 4122 are open. By forming the upper cutout groove 4122, the upper engagement claw 4121 becomes more easily flexible in the radial direction. The upper cutout groove 4122 also has an upper cutout groove recess 4122a that is concave radially inward from the upper end (see FIG. 6).

[0049] The upper cutout groove recess 4122a has, on the inner surface of the axial lower portion, an upper tapered portion 4122b that inclines axially upward as it approaches radially inward (see FIG. 6).

[0050] The upper recesses 4125 are recessed axially upward from the axial lower surface 4120 on the radially inner side of the upper cutout grooves 4122. The upper recesses 4125 are arranged side by side in two locations in the circumferential direction and radially opposed to the upper cutout grooves 4122.

[0051] The pair of upper engagement claws 4121, the upper cutout grooves 4122, and the upper recesses 4125 are disposed opposite each other in the radial direction with the central axis C in between.

[0052] The upper engaging male portion 4123 is formed to protrude radially outward from the radial outer surface 412a of the upper peripheral wall 412.

[0053] The upper protruding piece 4124 protrudes axially downward from the axial lower surface 4120, facing the upper engaging male part 4123 in the axial direction. The upper protruding piece 4124 has an upper guide recess 4124b and an upper protruding piece convex part 4124c. The upper guide recess 4124b is recessed radially inward from the radial outer surface 4124a, extends axially, and has an open lower end. The upper guide recess 4124b faces the upper engaging male part 4123 in the axial direction. The upper protruding piece convex part 4124c protrudes radially inward from the lower end of the upper protruding piece 4124 (see FIG. 6).

[0054] The upper convex portions 4126 protrude axially downward from the axial lower surface 4120 on the radially inner side of the upper protruding pieces 4124. The upper convex portions 4126 are arranged side by side in two locations in the circumferential direction and radially opposed to one upper protruding piece 4124.

[0055] The pair of upper engaging male parts 4123, upper projecting pieces 4124 and upper convex parts 4126 are disposed opposite each other in the radial direction with the central axis C in between.

[0056] The upper engagement claws 4121 and the upper engagement male parts 4123 are alternately arranged at equal intervals in the circumferential direction. That is, a plurality of pairs of upper engagement claws 4121 and upper cutout grooves 4122 facing each other in the radial direction are arranged at equal intervals in the circumferential direction. Also, a plurality of pairs of upper engagement male parts 4123 and upper protruding pieces 4124 facing each other in the axial direction are arranged at equal intervals in the circumferential direction.

[0057] The upper annular rib 4128 is formed in an annular shape, protrudes axially downward from the axial lower surface 4120 on the radial inner side of the upper recess 4125, and surrounds the central axis C.

[0058] <3.Detailed configuration of the lower housing> 5 is a perspective view of the lower housing 51, showing the state of the lower housing 51 as viewed from above in the axial direction. The lower peripheral wall 512 of the lower housing 51 has a pair of lower engagement claws 5121, a lower notched groove 5122, a lower engagement male portion (first engagement portion) 5123, a lower protruding piece 5124, a lower recess 5125, and a lower protrusion 5126. The lower peripheral wall 512 also has a lower annular rib 5128.

[0059] The lower engagement claw 5121 extends axially upward from the axial upper surface 5120 of the lower peripheral wall 512, and has a lower engagement female portion (fourth engagement portion) 5121a at its upper end. In this embodiment, the lower engagement female portion 5121a is formed as a through hole that penetrates the lower engagement claw 5121 in the radial direction. The lower engagement female portion 5121a is not limited to a through hole, and may be formed by forming a recess on the radial inner surface of the lower engagement claw 5121. The lower engagement claw 5121 is formed so that its circumferential width narrows toward the axial upper side.

[0060] The lower cutout groove 5122 is formed by cutting out the axially downward from the axial upper surface 5120 on the radially inner side of the lower engagement claw 5121. In other words, the lower cutout groove 5122 has a concave shape that is concave in the axial direction. Both circumferential ends of the lower cutout groove 5122 are open. By forming the lower cutout groove 5122, the lower engagement claw 5121 becomes more easily flexible in the radial direction. The lower cutout groove 5122 also has a lower cutout groove recess 5122a that is concave radially inward from the lower end (see FIG. 6).

[0061] The lower cutout groove recess 5122a has, on the inner surface of the axial upper portion, a lower tapered portion 5122b that inclines axially downward as it approaches radially inward (see FIG. 6).

[0062] The lower recesses 5125 are recessed axially upward from the axial upper surface 5120 on the radially inner side of the lower cutout grooves 5122. Two lower recesses 5125 are arranged side by side in the circumferential direction and radially opposed to one lower cutout groove 5122.

[0063] The pair of lower engagement claws 5121, the lower cutout grooves 5122, and the lower recesses 5125 are disposed opposite each other in the radial direction with the central axis C in between.

[0064] The lower engaging male portion 5123 is formed to protrude radially outward from a radial outer surface 512a of the lower peripheral wall 512.

[0065] The lower protruding piece 5124 protrudes axially upward from the axial upper surface 5120, facing the lower engaging male part 5123 in the axial direction. The lower protruding piece 5124 has a lower guide recess 5124b and a lower protruding piece protrusion 5124c. The lower guide recess 5124b is recessed radially inward from the radial outer surface 5124a, extends axially, and has an open upper end. The lower guide recess 5124b faces the lower engaging male part 5123 in the axial direction. The lower protruding piece protrusion 5124c protrudes radially inward from the upper end of the lower protruding piece 5124 (see FIG. 6).

[0066] The lower convex portions 5126 protrude axially upward from the axial upper surface 5120 on the radially inner side of the lower protruding pieces 5124. The lower convex portions 5126 are arranged side by side in two locations in the circumferential direction and radially opposed to the lower protruding pieces 5124.

[0067] The pair of lower engaging male parts 5123, the lower projecting pieces 5124 and the lower convex parts 5126 are disposed opposite each other in the radial direction with the central axis C in between.

[0068] The lower engagement claws 5121 and the lower engagement male parts 5123 are alternately arranged at equal intervals in the circumferential direction. That is, a plurality of pairs of lower engagement claws 5121 and lower cutout grooves 5122 facing each other in the radial direction are arranged at equal intervals in the circumferential direction. Also, a plurality of pairs of lower engagement male parts 5123 and lower protruding pieces 5124 facing each other in the axial direction are arranged at equal intervals in the circumferential direction.

[0069] The lower annular rib 5128 is formed in an annular shape, and protrudes axially downward from the axial upper surface 5120 on the radially inner side of the lower recess 5125 to surround the central axis C.

[0070] <4. Connection structure of upper and lower housing> 6 is an enlarged perspective view of a part of the housing 2. When the upper housing 41 and the lower housing 51 are joined, the lower end of the upper engagement claw 4121 is inserted into the upper end of the lower guide recess 5124b, and the upper end of the lower engagement claw 5121 is inserted into the lower end of the upper guide recess 4124b. At this time, the upper engagement claw 4121 and the lower engagement claw 5121 are formed so that the circumferential width becomes narrower toward the tip side. As a result, the upper engagement claw 4121 and the lower engagement claw 5121 are easily inserted into the upper end of the lower guide recess 5124b and the lower end of the upper guide recess 4124b, respectively. This improves the workability of assembling the housing 2.

[0071] Next, the upper housing 41 and the lower housing 51 are brought closer to each other. At this time, the upper guide recess 4124b and the lower guide recess 5124b guide the upper engagement claw 4121 and the lower engagement claw 5121 to the lower engagement female portion 5121a and the upper engagement female portion 4121a, respectively. By providing the upper guide recess 4124b and the lower guide recess 5124b, the workability of assembling the housing 2 is improved.

[0072] Thereafter, the upper engagement male part 4123 is inserted into and engaged with the lower engagement female part 5121a. Also, the lower engagement male part 5123 is inserted into and engaged with the upper engagement female part 4121a. As a result, the upper housing 41 and the lower housing 51 are fixed in the axial direction (see FIG. 1).

[0073] At this time, the upper engagement claw 4121 and the lower engagement claw 5121 are easily bent in the radial direction by forming the upper notch groove 4122 and the lower notch groove 5122. This allows the upper engagement claw 4121 and the lower engagement claw 5121 to easily move along the upper guide recess 4124b and the lower guide recess 5124b. Therefore, the workability of assembling the housing 2 can be improved while improving the rigidity of the upper housing 41 and the lower housing 51. In addition, the upper engagement claw 4121 and the lower engagement claw 5121 can be biased radially inward to more firmly engage the upper engagement male part 4123 and the lower engagement female part 5121a. In addition, the lower engagement male part 5123 and the upper engagement female part 4121a can be more firmly engaged. Furthermore, by forming the upper notch groove 4122 and the lower notch groove 5122, the upper engagement claw 4121 and the lower engagement claw 5121 are easily bent in the radial direction, thereby reducing the stress concentrated on the upper engagement claw 4121 and the lower engagement claw 5121.

[0074] Moreover, at least a portion of the lower protruding piece 5124 is positioned within the upper cutout groove 4122. Moreover, at least a portion of the upper protruding piece 4124 is positioned within the lower cutout groove 5122. In this embodiment, the lower protruding piece 5124 fits into the upper cutout groove 4122, and the upper protruding piece 4124 fits into the lower cutout groove 5122. This allows the upper housing 41 and the lower housing 51 to be firmly fixed in the circumferential direction (see FIG. 1).

[0075] At this time, the lower protruding piece convex portion 5124c contacts the upper tapered portion 4122b. Also, the upper protruding piece convex portion 4124c contacts the lower tapered portion 5122b. This reduces the contact area between the lower protruding piece convex portion 5124c and the upper tapered portion 4122b, and can reduce the contact area between the upper protruding piece convex portion 4124c and the lower tapered portion 5122b. Therefore, rattling at the contact surface can be reduced.

[0076] Furthermore, the upper convex portion 4126 is inserted into the lower recess 5125, and at least a portion of the upper convex portion 4126 is located within the lower recess 5125. The lower convex portion 5126 is inserted into the upper recess 4125, and at least a portion of the lower convex portion 5126 is located within the upper recess 4125. This makes it easy to position the upper housing 41 and the lower housing 51 in the circumferential direction, and improves the ease of assembly of the housing 2.

[0077] Furthermore, the lower annular rib 5128 and the upper annular rib 4128 come into contact with each other to connect the upper housing 41 and the lower housing 51. This reduces the contact area between the upper housing 41 and the lower housing 51, improving the accuracy of the flatness of the contact surfaces. As a result, rattling on the contact surfaces can be reduced.

[0078] In addition, a pair of upper engaging male parts 4123 and upper protruding pieces 4124 facing axially, a pair of lower engaging claws 5121 and lower cutout grooves 5122 facing radially, a pair of lower engaging male parts 5123 and lower protruding pieces 5124 facing axially, and a pair of upper engaging claws 4121 and upper cutout grooves 4122 facing radially are each arranged at equal intervals in the circumferential direction, so that the upper housing 41 and the lower housing 51 are stably fixed in the circumferential and axial directions.

[0079] <5.Other> Although the embodiment of the present invention has been described above, the scope of the present invention is not limited to this, and various modifications can be made without departing from the spirit of the invention. Furthermore, the above embodiment and its modifications can be combined in any suitable manner.

[0080] In this embodiment, the air intake 31 is provided at the upper end of the air flow passage 3, and the exhaust port 32 is provided at the lower end. However, the air intake 31 may be provided at the lower end of the air flow passage 3, and the exhaust port 32 may be provided at the upper end.

[0081] In this embodiment, the lower engagement male part (first engagement part) 5123 may be a female type and the upper engagement female part (second engagement part) 4121a may be a male type, and they may be engaged with each other. Also, the upper engagement male part (third engagement part) 4123 may be a female type and the lower engagement female part (fourth engagement part) 5121a may be a male type, and they may be engaged with each other.

[0082] In addition, the upper engaging male portion 4123 and upper protruding piece 4124 of the upper housing 41 may be omitted, and upper engaging claws 4121 and upper cutout grooves 4122 may be provided in multiple locations, and the lower engaging claws 5121 and lower cutout grooves 5122 of the lower housing 51 may be omitted, and lower engaging male portions 5123 and lower protruding pieces 5124 may be provided in multiple locations, to connect the upper housing 41 and the lower housing 51.

[0083] Similarly, the upper engagement claw 4121 and upper cutout groove 4122 of the upper housing 41 may be omitted, and an upper engagement male portion 4123 and upper protruding piece 4124 may be provided in multiple locations, and the lower engagement male portion 5123 and lower protruding piece 5124 of the lower housing 51 may be omitted, and a lower engagement claw 5121 and lower cutout groove 5122 may be provided in multiple locations, to connect the upper housing 41 and the lower housing 51. [Industrial Applicability]

[0084] The present invention can be used in, for example, an axial flow fan. [Explanation of symbols]

[0085] 1 Axial Fan 2. Housing 3 Air flow path 4 Upper Fan 5 Lower Fan 31 Air Intake 32 Exhaust port 41 Upper housing 42 Upper impeller 43 Upper motor 44 Upper circuit board 51 Lower housing 52 Lower impeller 53 Lower motor 54 Lower circuit board 411 Upper motor base 412 Upper peripheral wall 421 Upper impeller cup 422 Upper wing 431 Upper Shaft 432 Upper bearing 433 Upper Stator 434 Upper Rotor 511 Lower motor base 512 Lower peripheral wall 521 Lower impeller cup 522 Lower wing 531 Lower Shaft 532 Lower Bearing 533 Lower Stator 534 Lower Rotor 4111 Base 4112 Bearing holder 4113 Upper support part 4120 Axial bottom surface 4121 Upper engagement claw 4121a Upper engaging female part (second engaging part) 4122 Upper notch groove 4122a Upper notch groove recess 4122b Upper tapered section 4123 Upper engagement male part (third engagement part) 4124 Upper protruding piece 4124a Radial outer surface 4124b Upper guide recess 4124c Upper protruding piece convex part 4125 Upper recess 4126 Upper convex part 4128 Upper annular rib 4331, 5331 Stator core 4332, 5332 Insulator 4333, 5333 coils 4341, 5341 Rotor Yoke 4342, 5342 Magnets 5111 Base 5112 Bearing holder 5113 Lower support part 5120 Axial top surface 5121 Lower engagement claw 5121a Lower engaging female part (4th engaging part) 5122 Lower notch groove 5122a Lower notch groove recess 5122b Lower tapered section 5123 Lower engaging male part (first engaging part) 5124 Lower protruding piece 5124a Radial outer surface 5124b Lower guide recess 5124c Lower protruding piece convex part 5125 Lower recess 5126 Lower convex part 5128 Lower annular rib C center axis

Claims

1. a housing that surrounds a central axis extending vertically and is formed by connecting an upper housing disposed in an axial upper portion and a lower housing disposed in an axial lower portion; an upper motor accommodated in the upper housing and configured to rotate an upper impeller about the central axis; a lower motor accommodated in the lower housing and configured to rotate a lower impeller about the central axis, the upper housing has a cylindrical upper peripheral wall that covers the upper impeller and the upper motor from the radial outside, the lower housing has a cylindrical lower peripheral wall that covers the lower impeller and the lower motor from the radially outer side, The lower peripheral wall is a lower protruding piece that protrudes axially upward from an axial upper surface and engages with the upper housing; a lower protrusion protruding axially upward from an axial upper surface on the radial inner side of the lower protruding piece and a part of which is located within an upper recess recessed axially upward from an axial lower surface of the upper peripheral wall; or The upper peripheral wall is an upper protruding piece that protrudes axially downward from a lower surface of the lower housing and engages with the lower housing; an upper convex portion that protrudes axially downward from the axial lower surface radially inward of the upper protruding piece and has a portion located within a lower concave portion that is recessed axially downward from the axial upper surface of the lower peripheral wall.

2. The lower protruding piece and the lower convex portion face each other in a radial direction, or The axial flow fan according to claim 1 , wherein the upper protruding piece and the upper convex portion face each other in a radial direction.

3. The lower protruding piece extends axially further than the lower convex portion, or The axial flow fan according to claim 1 , wherein the upper protruding piece extends axially further than the upper convex portion extends axially.

4. The upper peripheral wall has an upper notch groove cut from an axially lower surface to an axially upper side, At least a portion of the lower protruding piece is located within the upper notch groove, or The lower peripheral wall has a lower notch groove cut from an axially upper surface to an axially lower side, The axial flow fan according to claim 1 , wherein at least a portion of the upper protruding piece is located within the lower notched groove.

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