Motors and Axial Fans

Abstract

To provide a motor capable of suppressing deformation of a housing of the motor.SOLUTION: A motor comprises: a rotor capable of rotating around a central axis extending vertically; a stator rotating the rotor; and a housing covering the rotor and the stator from the outward in a radial direction. The housing comprises: a first housing located at one side in an axial direction; and a second housing located at the other side in the axial direction. The first housing has: a first opposed surface opposed to the second housing in the axial direction; and a first wall part 41 extending from the first opposed surface toward the other side in the axial direction. The second housing has: a second opposed surface opposed to the first housing in the axial direction; a second wall part 51 extending from the second opposed surface toward the one side in the axial direction; and a base part holding the stator. The first and second wall parts are opposed to each other in the radial direction.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a motor and an axial flow fan. [Background technology]

[0002] A conventional motor includes a first housing and a second housing, which are stacked axially. A bearing holder, to which a stator core and the like are attached, is disposed in the second housing (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-105974 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional configuration described above, the bearing holder is provided in the second housing, not the first housing. As a result, the first housing has lower strength than the second housing. This means that the first housing may be deformed.

[0005] An object of the present invention is to suppress deformation of a motor housing. [Means for solving the problem]

[0006] An exemplary motor of the present invention includes a rotor rotatable about a central axis extending vertically, a stator that rotates the rotor, and a housing that radially covers the rotor and stator. The housing includes a first housing located on one axial side and a second housing located on the other axial side. The first housing has a first opposing surface that faces the second housing in the axial direction and a first wall portion extending from the first opposing surface to the other axial side. The second housing has a second opposing surface that faces the first housing in the axial direction, a second wall portion extending from the second opposing surface to one axial side, and a base portion that holds the stator. The first wall portion and the second wall portion face each other radially.

[0007] An exemplary axial flow fan of the present invention includes the motor described above and rotor blades attached to the rotor. [Effects of the Invention]

[0008] According to the exemplary motor and axial flow fan of the present invention, deformation of the motor housing can be suppressed. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of an axial flow fan according to an embodiment. [Figure 2] FIG. 2 is an exploded perspective view of the axial flow fan according to the embodiment. [Figure 3] FIG. 3 is a plan view of the housing according to the embodiment as viewed from the axial direction. [Figure 4] FIG. 4 is a perspective view of the first housing according to the embodiment. [Figure 5] FIG. 5 is a perspective view of the second housing according to the embodiment. [Figure 6] FIG. 6 is a schematic diagram showing a lead wire holding structure by a housing according to the embodiment. [Figure 7] FIG. 7 is a cross-sectional view of the housing according to the embodiment. [Figure 8] FIG. 8 is an enlarged view of the periphery of the corner shown in FIG. [Figure 9] FIG. 9 is an enlarged schematic view showing the axial positioning structure of the first housing according to the embodiment. [Figure 10] FIG. 10 is an enlarged schematic view showing a structure for positioning the first housing in the axial direction according to a modified example. [Figure 11] FIG. 11 is an enlarged cross-sectional view of the first wall portion, the second wall portion and their surroundings according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings.

[0011] In this specification, the direction in which the central axis CA of the motor 100 extends is referred to as the "axial direction," and the axial direction is defined as the up-down direction. However, this definition of the up-down direction does not limit the orientation or positional relationship of the motor 100 when in use.

[0012] In this specification, one axial direction is referred to as the “upper” direction, and the other axial direction is referred to as the “lower” direction. In addition, for each component, the end face of the upper end facing upward is referred to as the “upper end face,” and the end face of the lower end facing downward is referred to as the “lower end face.”

[0013] In this specification, the direction perpendicular to the central axis CA is referred to as the "radial direction." In addition, in the radial direction, the direction approaching the central axis CA is referred to as the "radially inner direction," and the direction moving away from the central axis CA is referred to as the "radially outer direction." In addition, for each component, the side surface facing radially inward is referred to as the "radially inner surface," and the side surface facing radially outward is referred to as the "radially outer surface."

[0014] In this specification, the circumferential direction about the central axis CA is referred to as the "circumferential direction."

[0015] <1. Axial flow fan> Fig. 1 is a perspective view of an axial fan 200 according to an embodiment of the present invention. Fig. 2 is an exploded perspective view of the axial fan 200 according to an embodiment of the present invention.

[0016] The axial flow fan 200 generates an airflow. The axial flow fan 200 includes a motor 100 and a rotor blade 210. The motor 100 is an outer rotor type. The rotor blade 210 is attached to the motor 100. Specifically, the rotor blade 210 is attached to a rotor 1, which will be described later. The motor 100 rotates the rotor blade 210. The rotation of the rotor blade 210 generates an airflow.

[0017] 2. Motor The motor 100 includes a rotor 1, a stator 2, and a housing 3. The motor 100 also includes a shaft 10.

[0018] The shaft 10 is arranged along a central axis CA that extends vertically. The shaft 10 is supported by a shaft holder 110. The shaft holder 110 extends axially in a cylindrical shape along the central axis CA. A bearing (not shown) that rotatably supports the shaft 10 is attached to the radially inner surface of the shaft holder 110.

[0019] The rotor 1 is rotatable about a central axis CA that extends vertically. The rotor 1 has a yoke 11 that is a cylindrical yoke with a lid. A yoke lid portion 111, which is the lid portion of the yoke 11, is disk-shaped and centered on the central axis CA. The yoke lid portion 111 has an opening at the radial center. The shaft 10 is fixed to the radially inner surface of the opening of the yoke lid portion 111. A yoke cylindrical portion 112, which is the cylindrical portion of the yoke 11, extends downward from the radial outer edge of the yoke lid portion 111. A magnet (not shown) is fixed to the radially inner surface of the yoke cylindrical portion 112.

[0020] The stator 2 rotates the rotor 1. The stator 2 is annular and centered on a central axis CA that extends vertically, and is disposed radially inward of the rotor 1. The radially outer surface of the stator 2 faces the radially inner surface of the rotor 1. Specifically, the radially outer surface of the stator 2 faces a magnet fixed to the radially inner surface of the yoke 11. The radially inner surface of the stator 2 is fixed to the radially outer surface of the shaft holder 110.

[0021] The stator 2 includes a stator core 21, an insulator 22, a coil 23, and a circuit board 24. The stator core 21 is an annular magnetic body centered on a central axis CA, and is a laminated body in which a plurality of plate-shaped electromagnetic steel sheets are stacked in the axial direction. The radially outer surface of the stator core 21 faces the magnet in the radial direction. The radially inner surface of the stator core 21 is fixed to the radially outer surface of the shaft holder 110.

[0022] The insulator 22 covers at least a portion of the stator core 21. The insulator 22 is an insulating member made of resin or the like. The coil 23 is formed by winding a conductive wire around the stator core 21 with the insulator 22 interposed therebetween. The circuit board 24 is electrically connected to the coil 23. Various electronic components are mounted on the circuit board 24.

[0023] The housing 3 covers the rotor 1 and the stator 2 from the radially outer side. The housing 3 also covers the rotor blades 210 attached to the rotor 1 from the radially outer side.

[0024] The motor 100 includes lead wires 20 (see FIG. 6). The lead wires 20 are electrically connected to the stator 2. Specifically, a plurality of lead wires 20 are connected to a circuit board 24. The lead wires 20 are drawn from the inside of the motor 100 to the outside. That is, the lead wires 20 are drawn from the radially inner side of the housing 3 to the radially outer side.

[0025] <3. Housing> FIG. 3 is a plan view of the housing 3 according to the embodiment, as viewed from the axial direction. In FIG. 3, the components arranged radially inward of the tubular portion 300 are not shown. Also, in FIG. 3, a diagonal line connecting the vertices of the housing 3 in a plan view is indicated by a two-dot chain line. Hereinafter, this diagonal line will be simply referred to as the diagonal line of the housing 3. The diagonal line of the housing 3 is a line connecting the vertices of a pair of corner portions 30 arranged opposite each other across the central axis CA. FIG. 4 is a perspective view of a first housing 4 according to the embodiment. FIG. 5 is a perspective view of a second housing 5 according to the embodiment. FIG. 6 is a schematic diagram showing a holding structure of the lead wire 20 by the housing 3 according to the embodiment. In FIG. 6, the lead wire 20 is shown in cross section.

[0026] <3-1. Housing configuration> The housing 3 includes a first housing 4 and a second housing 5. The first housing 4 is located on one side in the axial direction. The second housing 5 is located on the other side in the axial direction. That is, the first housing 4 is located on the upper side. The second housing 5 is located on the lower side. The first housing 4 and the second housing 5 are joined to each other in the axial direction.

[0027] The housing 3 also has a cylindrical portion 300 centered on the central axis CA. That is, the first housing 4 and the second housing 5 each have a cylindrical portion 300 centered on the central axis CA. The cylindrical portions 300 of the first housing 4 and the second housing 5 are joined to each other in the axial direction. In the following description, when it is necessary to distinguish between the cylindrical portions 300 of the first housing 4 and the second housing 5, the cylindrical portion 300 of the first housing 4 will be given the reference numeral 400 and will be referred to as the first cylindrical portion 400, and the cylindrical portion 300 of the second housing 5 will be given the reference numeral 500 and will be referred to as the second cylindrical portion 500.

[0028] The cylindrical portion 300 covers the rotor 1 and the stator 2 from the radially outer side. The rotor blades 210 are attached to the rotor 1. Therefore, the rotor blades 210 are covered from the radially outer side by the cylindrical portion 300. The cylindrical portion 300 guides the airflow generated by the rotation of the rotor blades 210 in the axial direction.

[0029] The housing 3 has an outer shape that is rectangular when viewed in the axial direction and has four corners 30. Each corner 30 may be rounded. For example, each corner 30 has a rounded chamfered shape. However, each corner 30 may also have a right-angled shape. Each corner 30 may also have a C-chamfered shape. In the following description, when it is necessary to distinguish between the four corners 30, the four corners 30 will be denoted by the reference numerals 30A, 30B, 30C, and 30D, respectively.

[0030] The corner portions 30 have through holes 31 that penetrate in the axial direction. One through hole 31 is provided at each of the four corner portions 30. The through holes 31 are arranged diagonally across the housing 3. A fastening member (not shown), such as a screw, is inserted into the through holes 31. The housing 3 is fixed to another member (not shown) by this fastening member.

[0031] The first housing 4 has a first opposing surface 40 that faces the second housing 5 in the axial direction. The second housing 5 has a second opposing surface 50 that faces the first housing 4 in the axial direction. Specifically, the first cylindrical portion 400 and the second cylindrical portion 500 have the first opposing surface 40 and the second opposing surface 50, respectively. The first cylindrical portion 400 has the first opposing surface 40 on its lower end surface, and the second cylindrical portion 500 has the second opposing surface 50 on its upper end surface.

[0032] The second housing 5 holds the shaft holder 110. In other words, the second housing 5 holds the stator 2. Specifically, the second housing 5 has a base portion 510 that holds the stator 2. For example, the base portion 510 is the same member as the second housing 5 and is formed integrally with the second housing 5.

[0033] The base portion 510 is disk-shaped and centered on the central axis CA. The shaft holder 110 is fixed to the radial center of the base portion 510. The base portion 510 also has a plurality of connecting portions 510a extending radially outward from its radially outer surface. The connecting portions 510a are connected to the radially inner surface of the second cylindrical portion 500. In other words, the connecting portions 510a connect the base portion 510 and the second cylindrical portion 500.

[0034] The second cylindrical portion 500 has a relatively high strength because the base portion 510 is connected to the second cylindrical portion 500 via the connecting portion 510a. On the other hand, no member equivalent to the base portion 510 is connected to the first cylindrical portion 400. Therefore, the second cylindrical portion 500 has a higher strength than the first cylindrical portion 400. In other words, the second cylindrical portion 500 is less likely to deform than the first cylindrical portion 400.

[0035] The cylindrical portion 300 also has a wiring portion 301 on which the lead wire 20 is arranged. Specifically, the first housing 4 has a wiring convex portion 401 on the first cylindrical portion 400, and the second housing 5 has a wiring concave portion 501 on the second cylindrical portion 500.

[0036] The wiring protrusion 401 extends downward from the lower end surface of the first cylindrical portion 400. On the other hand, the wiring recess 501 is recessed downward from the upper end surface of the second cylindrical portion 500 and penetrates the second cylindrical portion 500 in the radial direction. The wiring protrusion 401 is disposed in the wiring recess 501.

[0037] The wiring portion 301 is composed of a wiring protrusion 401 and a wiring recess 501 (see FIG. 6). Specifically, the wiring portion 301 is composed of a gap between the tip of the wiring protrusion 401 and the bottom of the wiring recess 501 in the axial direction. The lead wire 20 is disposed in the gap between the tip of the wiring protrusion 401 and the bottom of the wiring recess 501 in the axial direction. In other words, a through hole for wiring is formed by the gap between the tip of the wiring protrusion 401 and the bottom of the wiring recess 501 in the axial direction. The lead wire 20 is drawn out from the radially inner side of the housing 3 to the radially outer side through the through hole.

[0038] <3-2. Walls of the first and second housings> Fig. 7 is a cross-sectional view of the housing 3 according to the embodiment. Fig. 7 is a cross-sectional view of the first housing 4 fixed to the second housing 5, taken along a plane parallel to the radial direction. Fig. 8 is an enlarged view of the periphery of the corner portion 30 shown in Fig. 7.

[0039] The first housing 4 has a first wall portion 41 extending from the first opposing surface 40 to the other side in the axial direction. The first wall portion 41 extends downward from the first opposing surface 40. In other words, the first wall portion 41 extends from the first opposing surface 40 toward the second housing 5.

[0040] The second housing 5 has a second wall portion 51 extending from the second opposing surface 50 to one side in the axial direction. The second wall portion 51 extends upward from the second opposing surface 50. In other words, the second wall portion 51 extends from the second opposing surface 50 toward the first housing 4.

[0041] The first wall portion 41 and the second wall portion 51 face each other in the radial direction. As a result, even if the first housing 4, which has lower strength than the second housing 5, tries to deform in the radial direction, the deformation of the first housing 4 can be restricted by the second wall portion 51. In other words, the deformation of the first housing 4 can be suppressed. As a result, the deformation of the housing 3 can be suppressed.

[0042] The first wall portion 41 is disposed at one of the corners 30. Here, in a configuration in which the housing 3 has a rectangular outer shape, the thickness of the corners 30 of the housing 3 is greater than the thickness of other portions. Therefore, it is preferable to dispose the first wall portion 41 at one of the corners 30 of the housing 3. In other words, it is preferable to dispose the first wall portion 41 at one of the corners 30 of the first housing 4. This allows the thickness of the first wall portion 41 to be made large. As a result, the strength of the first wall portion 41 can be sufficiently ensured.

[0043] The first wall portions 41 are disposed at a pair of diagonally opposite corners 30 of the housing 3. This further suppresses deformation of the first housing 4. The first wall portions 41 may be disposed at the corners 30A and 30C on one diagonal line, or at the corners 30B and 30D on the other diagonal line. The first wall portions 41 may be disposed at all of the corners 30.

[0044] The first wall portion 41 is connected to a radially inner portion of the outer edge of the through hole 31. In other words, the first wall portion 41 has a connection portion 41a (see FIG. 8) connected to the outer edge of the through hole 31, and extends circumferentially from the connection portion 41a.

[0045] For example, the first wall portions 41 disposed at the corners 30A, 30B, and 30C extend from the connection portion 41a to one side and the other side in the circumferential direction. On the other hand, the first wall portion 41 disposed at the corner 30D extends from the connection portion 41a to one side in the circumferential direction but does not extend to the other side in the circumferential direction. The wiring portion 301 is provided on the other side in the circumferential direction of the connection portion 41a of the first wall portion 41 disposed at the corner 30D.

[0046] Furthermore, the first wall portion 41 and the second wall portion 51 are in contact with each other in the radial direction. With this configuration, deformation of the first housing 4 can be further suppressed.

[0047] Here, the rotor blades 210 that rotate around the central axis CA are arranged radially inward of the housing 3. In this configuration, if the first housing 4 deforms radially inward, the first housing 4 may come into contact with the rotor blades 210. In other words, there is a possibility that the housing 3 may come into contact with the rotor blades 210.

[0048] Therefore, the second wall portion 51 is disposed radially inward of the first wall portion 41. The radially inner surface of the first wall portion 41 contacts the radially outer surface of the second wall portion 51. This makes it possible to suppress radially inward deformation of the first housing 4. In other words, it is possible to suppress radially inward deformation of the housing 3. If radially inward deformation of the housing 3 can be suppressed, it is possible to suppress contact of the housing 3 with the rotor blades 210.

[0049] The second housing 5 further has a third wall portion 52 extending from the second opposing surface 50 to one side in the axial direction. The third wall portion 52 extends upward from the second opposing surface 50. That is, the third wall portion 52 extends from the second opposing surface 50 toward the first housing 4.

[0050] The third wall portion 52 is disposed radially outward of the first wall portion 41. The first wall portion 41 and the third wall portion 52 face each other radially. As a result, even if the first housing 4, which has lower strength than the second housing 5, attempts to deform radially outward, the deformation of the first housing 4 can be restricted by the third wall portion 52. In other words, the radially outward deformation of the first housing 4 can be suppressed. As a result, the radially outward deformation of the housing 3 can be suppressed.

[0051] Furthermore, the third wall portion 52 faces the second wall portion 51 in the radial direction with the first wall portion 41 interposed therebetween. That is, at least a portion of the first wall portion 41 is disposed radially between the second wall portion 51 and the third wall portion 52. This forms a labyrinth structure in the region where the first wall portion 41 is disposed radially between the second wall portion 51 and the third wall portion 52. As a result, in addition to suppressing radial deformation of the first housing 4, it is also possible to suppress leakage of air in the radial direction from the interface between the first housing 4 and the second housing 5.

[0052] <3-3. Circumferential positioning of the first housing> A portion of the first wall portion 41 does not face the third wall portion 52 in the radial direction. Specifically, the first wall portion 41 has an overlapping portion 411 (see FIG. 8 ) that overlaps with the third wall portion 52 in the radial direction. On the other hand, the first wall portion 41 also has a portion that does not overlap with the third wall portion 52 in the radial direction. In other words, the first wall portion 41 has a circumferential end portion 412 that protrudes in the circumferential direction beyond the overlapping portion 411. The circumferential end portion 412 is a non-overlapping portion that does not overlap with the third wall portion 52 in the radial direction.

[0053] The circumferential end portion 412 has a protruding portion 413 that protrudes radially outward. For example, the protruding portion 413 protrudes radially outward beyond the radially outer surface of the third wall portion 52. The protruding portion 413 faces the surface of the third wall portion 52 that faces in the circumferential direction. In other words, the protruding portion 413 has a surface that faces the surface of the third wall portion 52 that faces in the circumferential direction.

[0054] By arranging the circumferential surface of the third wall portion 52 and the protrusion 413 facing each other, it is possible to position the first housing 4 in the circumferential direction. In addition, it is possible to suppress deformation of the first housing 4 in the circumferential direction. Note that the circumferential surface of the third wall portion 52 and the protrusion 413 may come into contact with each other. In this case, it is possible to further suppress deformation of the first housing 4 in the circumferential direction.

[0055] The first wall portion 41 also has a protrusion 414 that protrudes radially inward. The protrusion 414 protrudes radially inward further than the overlapping portion 411. The second wall portion 51 has a recess 511. The recess 511 is recessed toward the other side in the axial direction. Specifically, the recess 511 is recessed downward from the upper end surface of the second wall portion 51. The recess 511 also penetrates the second wall portion 51 in the radial direction.

[0056] The protrusions 414 are disposed in the recesses 511. That is, the outer circumferential surfaces of the protrusions 414 face the inner circumferential surfaces of the recesses 511. The outer circumferential surfaces of the protrusions 414 may come into contact with the inner circumferential surfaces of the recesses 511. This allows the first housing 4 to be positioned in the circumferential direction. When the outer circumferential surfaces of the protrusions 414 and the inner circumferential surfaces of the recesses 511 come into contact with each other, deformation of the first housing 4 in the circumferential direction can be further suppressed.

[0057] The protrusions 414 are disposed on the connecting portion 41a (see FIG. 8). In other words, the protrusions 414 protrude radially inward from a radially inner portion of the outer edge of the through hole 31. Therefore, the radially inner portion of the outer edge of the through hole 31 becomes thicker by the amount of the protrusions 414 protruding radially inward. This increases the strength of the outer edge of the through hole 31.

[0058] <3-4. Axial positioning of the first housing> Fig. 9 is an enlarged schematic view showing an axial positioning structure for the first housing 4 according to the embodiment. Fig. 10 is an enlarged schematic view showing an axial positioning structure for the first housing 4 according to a modified example.

[0059] An end face of the second wall portion 51 facing one side in the axial direction comes into contact with the first opposing surface 40 (see FIG. 9). That is, the upper end face of the second wall portion 51 comes into contact with the first opposing surface 40. For example, the entire upper end face of the second wall portion 51 comes into contact with the first opposing surface 40. This positions the first housing 4 in the axial direction, and makes it possible to prevent the first housing 4 from shifting in the axial direction relative to the second housing 5.

[0060] Furthermore, it is possible to prevent gaps from occurring at the joint between the first housing 4 and the second housing 5 on the inner circumferential surface of the tubular portion 300 of the housing 3. If there is a gap at the joint between the first housing 4 and the second housing 5, it will have an effect such as turbulence on the airflow generated radially inside the tubular portion 300. However, if there is no gap at the joint between the first housing 4 and the second housing 5, it is possible to prevent the influence on the airflow generated radially inside the tubular portion 300. This improves the airflow blowing efficiency of the axial flow fan 200.

[0061] Note that, with regard to the axial positioning of the first housing 4, the configuration of a modified example shown in FIG. 10 may be adopted. In this modified example, the end face of the second wall portion 51 facing one axial side does not contact the first opposing surface 40. On the other hand, the end face of the first wall portion 41 facing the other axial side contacts the second opposing surface 50. That is, the lower end face of the first wall portion 41 contacts the second opposing surface 50. For example, the entire lower end face of the first wall portion 41 contacts the second opposing surface 50. Even when the configuration of the modified example shown in FIG. 10 is adopted, the first housing 4 is positioned in the axial direction, and axial displacement of the first housing 4 relative to the second housing 5 can be suppressed.

[0062] <3-5. Fixing structure between the first housing and the second housing> The first housing 4 has at least one of engagement claws 310 protruding radially and engagement holes 320 engaging with the engagement claws 310 (see FIG. 4). The second housing 5 has at least the other of engagement claws 310 and engagement holes 320 (see FIG. 5). The engagement claws 310 protrude radially outward. The engagement holes 320 penetrate radially.

[0063] When the first housing 4 has the engaging claws 310, the second housing 5 has at least the engaging holes 320 that engage with the engaging claws 310 of the first housing 4. When the first housing 4 has the engaging holes 320, the second housing 5 has at least the engaging claws 310 that engage with the engaging holes 320 of the first housing 4.

[0064] The engagement claws 310 are attached to the engagement holes 320 by a snap fit method. That is, the engagement claws 310 and the engagement holes 320 are engaged with each other by utilizing the elastic deformation of the first housing 4 and the second housing 5. This makes it possible to easily fix the first housing 4 to the second housing 5.

[0065] Furthermore, when attaching the second housing 5 to the first housing 4, it is sufficient to simply fit the first housing 4 into the second housing 5 from above. In other words, there is no need for a jig to fix the first housing 4 and the second housing 5 in place during the attachment work, which makes the attachment work easier.

[0066] In this embodiment, the first housing 4 has two engagement claws 310 and two engagement holes 320. The second housing 5 has two engagement claws 310 and two engagement holes 320. These engagement claws 310 and engagement holes 320 are arranged on diagonal lines of the housing 3 when viewed from the axial direction. In the following description, the first diagonal line of the housing 3 is designated by the symbol L1, and the second diagonal line of the housing 3 is designated by the symbol L2 (see FIG. 3).

[0067] The engagement claws 310 of the first housing 4 are respectively arranged at a pair of corners 30 located on the first diagonal line L1. The engagement holes 320 of the first housing 4 are respectively arranged at a pair of corners 30 located on the second diagonal line L2. The engagement holes 320 of the second housing 5 are respectively arranged at a pair of corners 30 located on the first diagonal line L1. The engagement claws 310 of the second housing 5 are respectively arranged at a pair of corners 30 located on the second diagonal line L2.

[0068] In this configuration, the first housing 4 and the second housing 5 are fixed to each other at four locations, so that the first housing 4 and the second housing 5 can be fixed to each other more firmly.

[0069] The engagement claws 310 protrude radially outward from the outer surface of the tubular portion 300. Meanwhile, the engagement holes 320 are formed in tongue portions 321 (see FIGS. 3 and 4) extending axially from the axial end surface of the tubular portion 300. In this configuration, when attaching the first housing 4 to the second housing 5, it is necessary to insert the mating tubular portion 300 between the pair of tongue portions 321 facing radially.

[0070] Therefore, for example, in a configuration in which engagement claws 310 are provided on all four corners 30 of the first housing 4 (or the second housing 5) and engagement holes 320 are provided on all four corners 30 of the second housing 5 (or the first housing 4), if the first housing 4 is tilted relative to the second housing 5 during the installation work of the first housing 4 to the second housing 5, it becomes difficult to install the first housing 4 to the second housing 5.

[0071] On the other hand, in the configuration of the embodiment, the first housing 4 has tongue portions 321 at a pair of corners 30 located on the second diagonal line L2, but does not have tongue portions 321 at a pair of corners 30 located on the first diagonal line L1. In other words, the second housing 5 has tongue portions 321 at a pair of corners 30 located on the first diagonal line L1, but does not have tongue portions 321 at a pair of corners 30 located on the second diagonal line L2. This makes it easier to insert the mating tubular portion 300 between the pair of radially opposing tongue portions 321. As a result, the attachment work of the first housing 4 to the second housing 5 is facilitated.

[0072] <4. Modifications> Fig. 11 is an enlarged cross-sectional view of the first wall 41, the second wall 51, and their surroundings according to a modified example. Fig. 11 is a cross-sectional view of the first housing 4 fixed to the second housing 5, cut along a plane parallel to the radial direction.

[0073] The second wall portion 51 has a protrusion 512 on its radially outer surface. The protrusion 512 protrudes radially outward. The protrusion 512 contacts the radially inner surface of the first wall portion 41. For example, the protrusion 512 may extend linearly in the axial direction. The protrusion 512 may also be dot-shaped. In this modified example, by precisely forming the amount of radial outward protrusion of the protrusion 512, it is possible to suppress radial displacement of the first housing without precisely finishing the entire radially outer surface of the second wall portion 51.

[0074] <5.Other> The embodiments of the present invention have been described above. However, the scope of the present invention is not limited to the above-described embodiments. The present invention can be implemented by adding various modifications within the scope of the gist of the invention. Furthermore, the above-described embodiments can be combined in any appropriate manner. [Industrial Applicability]

[0075] The present invention can be used, for example, as a motor for an axial flow fan. [Explanation of symbols]

[0076] 1 rotor 2 stator 3. Housing 4. First Housing 5 Second Housing 30 Corner 31 Through hole 40 First opposing surface 41 1st wall 41a Connection 50 Second opposing surface 51 2nd wall section 52 Third wall 100 motor 200 axial fan 210 Moving blade 310 Engagement claw 320 Engagement hole 411 Superimposed part 412 Circumferential end 413 Protrusion 414 Convex 510 Base 511 recess 512 Protrusion CA center axis L1 First diagonal L2 Second diagonal

Claims

1. a rotor that can rotate around a central axis that extends vertically; a stator that rotates the rotor; a housing that covers the rotor and the stator from the outside in the radial direction, The housing includes: a first housing located on one side in the axial direction; a second housing located on the other side in the axial direction, The first housing includes: a first opposing surface opposing the second housing in the axial direction; a first wall portion extending from the first opposing surface to the other side in the axial direction, The second housing includes: a second opposing surface opposing the first housing in the axial direction; a second wall portion extending from the second opposing surface to one side in the axial direction; a base portion that holds the stator, the first wall portion and the second wall portion face each other in a radial direction, the second wall portion is disposed radially inward of the first wall portion, the second housing further includes a third wall portion extending from the second opposing surface to one side in the axial direction, the third wall portion is disposed radially outward of the first wall portion, The first wall portion is an overlapping portion overlapping the third wall portion in the radial direction; a circumferential end portion that protrudes in the circumferential direction beyond the overlapping portion, the circumferential end portion has a protruding portion that protrudes radially outward, The protrusion faces an end surface of the third wall portion facing the circumferential direction.

2. The motor according to claim 1 , wherein the first wall portion and the second wall portion contact each other in the radial direction.

3. the second wall portion has a protrusion on a radially outer surface, The motor according to claim 2 , wherein the protrusion protrudes radially outward and contacts a radially inner surface of the first wall portion.

4. 4. The motor according to claim 1, wherein an end surface of the second wall portion facing one side in the axial direction is in contact with the first opposing surface.

5. 4. The motor according to claim 1, wherein an end surface of the first wall portion facing the other side in the axial direction is in contact with the second opposing surface.

6. The motor according to any one of claims 1 to 5, wherein the third wall portion faces the second wall portion in the radial direction with the first wall portion interposed therebetween.

7. the first wall portion has a convex portion that protrudes radially inward beyond the overlapping portion, the second wall portion has a recessed portion recessed toward the other side in the axial direction and penetrating in the radial direction, The motor according to any one of claims 1 to 6, wherein the protrusion is disposed in the recess.

8. The housing has an outer shape that is quadrangular with four corners when viewed from the axial direction, The corner portion has a through hole penetrating in the axial direction, the first wall portion has a connection portion connected to an outer edge portion of the through hole, and extends from the connection portion in the circumferential direction; The motor according to claim 7 , wherein the protrusion is disposed on the connection portion.

9. The housing has an outer shape that is quadrangular with four corners when viewed from the axial direction, The motor according to any one of claims 1 to 7, wherein the first wall portion is disposed at one of the corner portions.

10. The motor according to claim 9 , wherein the first wall portions are respectively disposed at a pair of the corner portions located diagonally opposite each other of the housing.

11. the first housing has at least one of an engagement claw protruding in the radial direction and an engagement hole engaging with the engagement claw, The motor according to any one of claims 1 to 7, wherein the second housing has at least the other of the engagement claw and the engagement hole.

12. a rotor that can rotate around a central axis that extends vertically; a stator that rotates the rotor; a housing that covers the rotor and the stator from the outside in the radial direction, The housing includes: a first housing located on one side in the axial direction; a second housing located on the other side in the axial direction, The first housing includes: a first opposing surface opposing the second housing in the axial direction; a first wall portion extending from the first opposing surface to the other side in the axial direction, The second housing includes: a second opposing surface opposing the first housing in the axial direction; a second wall portion extending from the second opposing surface to one side in the axial direction; a base portion that holds the stator, the first wall portion and the second wall portion face each other in a radial direction, the first housing has at least one of an engagement claw protruding in the radial direction and an engagement hole engaging with the engagement claw, the second housing has at least the other of the engagement claw and the engagement hole, The housing has an outer shape that is quadrangular with four corners when viewed from the axial direction, the first housing has two of the engagement claws and two of the engagement holes; the second housing has two of the engagement claws and two of the engagement holes; the engaging claws of the first housing are respectively arranged at a pair of corners located on a first diagonal line of the housing, and the engaging holes of the first housing are respectively arranged at a pair of corners located on a second diagonal line of the housing, A motor, wherein the engagement holes of the second housing are respectively positioned at a pair of corners located on the first diagonal line, and the engagement claws of the second housing are respectively positioned at a pair of corners located on the second diagonal line.

13. A motor according to any one of claims 1 to 12; and a rotor blade attached to the rotor.

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