Motor and air blower

Abstract

To provide a motor capable of reducing an outer shape of a circuit board.SOLUTION: A motor 11 includes: a shaft 19 extending in an axial direction about a central axis; a rotor 13 rotatable about the shaft; a stator 21 opposed to the rotor with a gap therebetween; a support part 23 supporting the stator; and a circuit board 25 electrically connected to the stator and configured to switch a current flowing through the stator. The support part includes: a bearing 37 that rotatably supports the shaft; and a cylindrical part 35 that supports the bearing on a radially inner surface. The stator is supported on a radially outer surface of the cylindrical part. The circuit board is located on one side of the support part in the axial direction. The support part and at least a part of the circuit board overlap each other in the axial direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to motors and blowers. [Background technology]

[0002] There is known a motor in which a rotor shaft is rotatably disposed inside a cylindrical portion and a stator is disposed outside the cylindrical portion (see, for example, Patent Document 1). In such a motor, a circuit board is disposed around the cylindrical portion and is electrically connected to the stator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6180020 Summary of the Invention [Problem to be solved by the invention]

[0004] In such conventional motors, the cylindrical portion is disposed in a through hole formed in the circuit board, which poses a problem that the external dimensions of the circuit board tend to increase in size in order to ensure sufficient area for the circuit board.

[0005] In view of the above circumstances, one object of the present disclosure is to provide a motor and a fan that can reduce the external dimensions of a circuit board. [Means for solving the problem]

[0006] One aspect of the motor disclosed herein includes a shaft extending axially around a central axis, a rotor rotatable around the shaft, a stator facing the rotor across a gap, a support portion supporting the stator, and a circuit board electrically connected to the stator and switching the current flowing through the stator. The support portion has a bearing that rotatably supports the shaft and a cylindrical portion that supports the bearing on its radially inner surface. The stator is supported on the radially outer surface of the cylindrical portion. The circuit board is located on one axial side of the support portion. The support portion and at least a portion of the circuit board overlap in the axial direction.

[0007] One aspect of a blower according to the present disclosure includes the motor described above and an impeller portion provided on the rotor. [Effects of the Invention]

[0008] According to one aspect of the present disclosure, the outer dimensions of the circuit board in the motor and the fan can be reduced. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view of a blower using a motor according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional perspective view showing a state in which the rotor is removed in the motor of the embodiment. [Figure 3] FIG. 3 is a plan view showing a state in which the rotor and stator windings have been removed in the motor of one embodiment. [Figure 4] FIG. 4 is a bottom view of the bottom plate and the circuit board in the motor of the embodiment. [Figure 5] FIG. 5 is a bottom view of the bottom plate and the circuit board in the motor of the modified example. [Figure 6] FIG. 6 is a bottom view of the bottom plate portion and the circuit board in the motor of another modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, motors and blowers according to embodiments of the present disclosure will be described with reference to the drawings. Note that the scope of the present disclosure is not limited to the following embodiments and can be modified as desired within the scope of the technical concept of the present disclosure. In addition, in the following drawings, the scale and number of components may differ from the actual structure to make each component easier to understand.

[0011] In each drawing, a central axis J of the motor in each of the following embodiments is shown as appropriate. The central axis J is a virtual axis. In the following description, the direction in which the central axis J extends, i.e., the axial direction of the central axis J, will be simply referred to as the "axial direction," the radial direction centered on the central axis J will be simply referred to as the "radial direction," and the circumferential direction centered on the central axis J will be simply referred to as the "circumferential direction." In each drawing, a Z axis parallel to the axial direction is shown. In the following description, the side of the axial direction toward which the arrow of the Z axis points (+Z side) will be referred to as the "upper side," and the side of the axial direction opposite to the side toward which the arrow of the Z axis points (-Z side) will be referred to as the "lower side." In each of the following embodiments, the lower side corresponds to "one axial side," and the upper side corresponds to "the other axial side." Note that the terms "upper side" and "lower side" are simply names used to describe the relative positions of the components, and the actual relative positions may be different from those indicated by these names.

[0012] As shown in FIG. 1 or 2 , blower 10 of this embodiment includes motor 11, impeller unit 15, and housing 17. Housing 17 is frame-shaped and surrounds central axis J, with openings on both axial sides. Motor 11 and impeller unit 15 are housed radially inside housing 17. Motor 11 includes shaft 19, rotor 13, stator 21, support unit 23, bottom wall unit 39, and circuit board 25.

[0013] As shown in FIG. 1 or 2, the shaft 19 extends in the axial direction around a central axis J. The shaft 19 is supported by a support portion 23 so as to be rotatable around the central axis J. A lower end of the shaft 19 is disposed inside a cylindrical portion 35, which will be described later. A magnet 51 is attached to the lower end of the shaft 19.

[0014] As shown in FIG. 1 , the rotor 13 is fixed to the upper end of the shaft 19. The rotor 13 is rotatable around the shaft 19. The rotor 13 has an annular wall portion 29 and a rotor magnet 28. The annular wall portion 29 is annular and surrounds the central axis J. The annular wall portion 29 is located radially outside the stator 21 and surrounds the stator 21. The rotor magnet 28 is fixed to the radially inner surface of the annular wall portion 29. The rotor 13 is provided with an impeller portion 15. The impeller portion 15 has a plurality of blade portions 15a provided on the radially outer surface of the annular wall portion 29.

[0015] As shown in FIG. 1 or 2, the stator 21 faces the rotor 13 with a gap therebetween. The stator 21 is located radially inside the annular wall portion 29. The stator 21 is supported by the support portion 23 on the radially outer surface of a cylindrical portion 35 (described later). The stator 21 includes a stator core 31, a winding 33, and an insulator 34. The stator core 31 includes a core back 31a surrounding the cylindrical portion 35 and teeth 31b extending radially outward from the core back 31a. The radially inner surface of the core back 31a is fixed to the radially outer surface of the cylindrical portion 35 (described later). The winding 33 is attached to the stator core 31 via the insulator 34. As shown in FIG. 3, the insulator 34 includes a protrusion 34a. The protrusion 34a protrudes radially outward from a portion of the insulator 34 that covers the core back 31a from the radially outer side. A plurality of protrusions 34a are provided at intervals in the circumferential direction, and in this embodiment, four protrusions 34a are provided.

[0016] The support portion 23 supports the stator 21. As shown in FIG. 1 or 2, the support portion 23 has a cylindrical portion 35 and a bearing 37. The cylindrical portion 35 is cylindrical and surrounds the central axis J. In this embodiment, the cylindrical portion 35 is generally cylindrical and has an opening on both sides in the axial direction, with the central axis J as its center. That is, the cylindrical portion 35 has an opening 35a at the lower end of the cylindrical portion 35. The opening 35a has a circular shape centered on the central axis J when viewed in the axial direction. The stator core 31 is fixed to the radially outer surface of the cylindrical portion 35. The cylindrical portion 35 supports the bearing 37 on its radially inner surface.

[0017] As shown in FIG. 1 or 2, bearing 37 rotatably supports shaft 19. In this embodiment, bearing 37 is a ball bearing. Bearing 37 is fitted and held inside cylindrical portion 35. Two bearings 37 are provided, spaced apart in the axial direction. Note that bearing 37 may be a rolling bearing other than a ball bearing, or may be a sliding bearing, as long as it can rotatably support shaft 19.

[0018] As shown in FIG. 1 or 2, the bottom wall portion 39 extends radially outward from the lower end of the cylindrical portion 35. The bottom wall portion 39 is annular and surrounds the central axis J. In this embodiment, the bottom wall portion 39 is annular and centered on the central axis J. The bottom wall portion 39 is disposed below the stator 21 with a gap therebetween. In this embodiment, the bottom wall portion 39 is plate-shaped with its plate surface facing the axial direction. The bottom wall portion 39 has a through hole 43 that penetrates the bottom wall portion 39 in the axial direction. As shown in FIG. 4, a plurality of through holes 43 are provided. In this embodiment, four through holes 43 are provided. The bottom wall portion 39 is connected to the housing 17, for example, via a connecting portion (not shown).

[0019] As shown in FIG. 1 or 2 , the plate surface of the circuit board 25 faces the axial direction. The circuit board 25 is located below the support portion 23. In this embodiment, the circuit board 25 is fixed to the underside of the bottom wall portion 39. The upper surface of the circuit board 25 is in contact with the lower surface of the bottom wall portion 39. Note that the circuit board 25 may be disposed below and spaced apart from the lower surface of the bottom wall portion 39 via a board support portion or the like provided on the lower surface of the bottom wall portion 39. The fixing means for fixing the circuit board 25 to the bottom wall portion 39 is not particularly limited. The fixing means for fixing the circuit board 25 to the bottom wall portion 39 may be appropriately selected from, for example, snap fitting, screwing, welding, adhesive, etc.

[0020] As shown in FIG. 1 or 2 , the winding 33 is electrically connected to the circuit board 25 via a conductive member 45. This electrically connects the circuit board 25 to the stator 21. The conductive member 45 is a metal member extending in the axial direction. In this embodiment, the conductive member 45 is a binding pin around which an end of the conductive wire constituting the winding 33 is wound. The conductive member 45 is held by the protrusion 34a. The conductive member 45 axially penetrates the protrusion 34a. A portion of the conductive member 45 located below the protrusion 34a is passed through the through hole 43 and connected to the circuit board 25. This connects the winding 33 and the circuit board 25. A portion of the conductive member 45 is disposed within the through hole 43. The conductive member 45 axially penetrates the circuit board 25 and is connected to the circuit board 25 by solder 47.

[0021] An inverter circuit that supplies current to windings 33 of stator 21 is provided on circuit board 25. The inverter circuit supplies current to windings 33 via conductive member 45. Circuit board 25 switches the current flowing through stator 21 using the inverter circuit.

[0022] As shown in Fig. 4, in this embodiment, the circuit board 25 has a square shape with four arc-shaped corners. That is, in this embodiment, the circuit board 25 has a polygonal shape. In this embodiment, shapes with arc-shaped corners are also included in the polygonal shape. The arc-shaped corners of the circuit board 25 in this embodiment are arc-shaped with the center axis J as the center. The radially outer edge of the circuit board 25 is located radially inward of the radially outer edge of the bottom wall portion 39.

[0023] Here, circuit board 25 is required to have a sufficient mounting area for mounting the circuits and electronic components required for motor 11. However, for example, if circuit board 25 is to be fixed to the upper surface of bottom wall portion 39, it becomes necessary to provide a through-hole in circuit board 25 for passing cylindrical portion 35 of support portion 23 therethrough, which results in the external dimensions of circuit board 25 becoming larger.

[0024] To address the above problem, in this embodiment, as shown in FIG. 1 or 2, circuit board 25 is located below support portion 23, and support portion 23 and at least a portion of circuit board 25 overlap in the axial direction. Therefore, there is no need to provide a through hole in circuit board 25 to avoid support portion 23. This allows the outer shape of circuit board 25 to be smaller than when a through hole for passing tubular portion 35 is provided in circuit board 25, while still ensuring a mounting area for mounting electronic components and the like. Furthermore, even if the outer shape of circuit board 25 remains unchanged, the mounting area of ​​circuit board 25 can be increased by the amount that a portion of circuit board 25 can be provided in the area where a through hole would previously have been provided.

[0025] Note that "at least a portion of the support portion 23 and the circuit board 25 overlap in the axial direction" means that at least a portion of the circuit board 25 has a portion that is located inside the outline of the support portion 23 when viewed in the axial direction. In this embodiment, the outline of the support portion 23 is the line that represents the cylindrical portion 35, which is shown by the dashed line in Figure 4. In this embodiment, the portion of the circuit board 25 that is located inside the circular dashed line that represents the cylindrical portion 35 in Figure 4 is the portion that overlaps with the support portion 23 in the axial direction.

[0026] Furthermore, in this embodiment, there is no need to provide a through hole in the circuit board 25 for passing the cylindrical portion 35 therethrough, which increases the degree of freedom in the shape of the circuit board 25. In this embodiment, the circuit board 25 has a polygonal shape. Therefore, compared to when the circuit board 25 is circular, the yield when manufacturing a plurality of circuit boards 25 from a base material can be improved.

[0027] In this embodiment, the circuit board 25 is fixed to the underside of the bottom wall portion 39. Therefore, the circuit board 25 can be stably arranged below the support portion 23, and it is easy to arrange the circuit board 25 so that a portion of the circuit board 25 overlaps with the support portion 23 in the axial direction.

[0028] In this embodiment, a portion of conductive member 45 connecting winding 33 and circuit board 25 is disposed in through-hole 43 provided in bottom wall portion 39. Therefore, winding 33 and circuit board 25 can be electrically connected via conductive member 45 while circuit board 25 is fixed to the underside of bottom wall portion 39. Furthermore, conductive member 45 can be formed in a simple shape extending in the axial direction.

[0029] In this embodiment, the circuit board 25 covers at least a portion of the opening 35a. Therefore, it is possible to mount electronic components on the upper surface of the portion of the circuit board 25 that covers at least a portion of the opening 35a. In other words, it is possible to arrange electronic components by utilizing the interior of the opening 35a. This makes it possible to further reduce the outer shape of the circuit board 25 while ensuring a sufficient mounting area for the circuit board 25. Furthermore, if the outer size of the circuit board 25 is not changed, it is possible to further increase the mounting area for the circuit board 25. In this embodiment, the circuit board 25 covers the entire opening 35a. Therefore, it is possible to further reduce the outer shape of the circuit board 25. Furthermore, it is possible to further increase the mounting area for the circuit board 25.

[0030] In this embodiment, electronic components 49 are mounted on the lower surface of the circuit board 25. In this embodiment, the circuit board 25 is located below the support portion 23, and therefore the lower surface of the circuit board 25 is the surface of the circuit board 25 opposite the surface facing the stator 21. As a result, by mounting the electronic components 49 on the lower surface of the circuit board 25, the axial dimension of the electronic components 49 is not limited by the size of the gaps between the stator 21 and the rotor 13 and the circuit board 25. Therefore, the electronic components 49 can be mounted on the circuit board 25 without considering their relationship to the stator 21 and the rotor 13. Furthermore, because the electronic components 49 are not provided in positions axially opposite the stator 21 and the rotor 13, the stator 21 and the rotor 13 can be disposed closer to the bottom wall portion 39. This facilitates the axial miniaturization of the motor 11.

[0031] In this embodiment, electronic components 49 are mounted on the portion of the upper surface of circuit board 25 facing opening 35a. Therefore, opening 35a can be used to arrange electronic components 49. This prevents the external dimensions of circuit board 25 from becoming too large, and allows the required board area to be obtained with less board material. Furthermore, by not providing through holes in circuit board 25 as described above, board material can be saved.

[0032] In this embodiment, a magnetic sensor 49a that faces the magnet 51 in the axial direction is mounted on a portion of the upper surface of the circuit board 25 that faces the opening 35a. Therefore, the rotation of the shaft 19 can be detected by the magnet 51 provided on the shaft 19 and the magnetic sensor 49a mounted on the circuit board 25, thereby detecting the rotation of the rotor 13. By arranging the magnetic sensor 49a using the opening 35a in this manner, it becomes easy to arrange a signal line that transmits a signal from the magnetic sensor 49a to an electronic component 49 that switches the current flowing through the stator 21, for example.

[0033] (Variation 1) As shown in FIG. 5, in the motor 11A of this modification, the circuit board 25A has a polygonal shape. Specifically, the circuit board 25A has a quadrilateral shape with four corners that are not arc-shaped. The circuit board 25A may have any other polygonal shape. The rest is the same as the motor 11 of the above embodiment. Even with this motor 11A, it is possible to achieve the same effects as the above embodiment. Furthermore, the circuit board 25A of this modification can have a simpler shape, thereby further improving material yield.

[0034] (Variation 2) As shown in Figure 6, in motor 11B of this modified example, circuit board 25B is circular and has deformed portions 53 at a pair of symmetrical positions on the circle. The pair of deformed portions 53 are linear edges that are parallel to each other and located at symmetrical positions on either side of central axis J. The rest is the same as in the above modified example. This motor 11B can also achieve the same effects as in the above modified example.

[0035] Although the embodiments and modifications of the present disclosure have been described above, the configurations and combinations thereof in the embodiments and modifications are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible without departing from the spirit of the present disclosure. Furthermore, the present disclosure is not limited to the embodiments.

[0036] For example, the above describes an example in which the motor is used in a blower. However, the application of the motor is not particularly limited. The above motor may also be used in devices other than a blower. Furthermore, the circuit board does not have to cover the opening of the cylindrical portion. Furthermore, the electronic components may be provided only on one axial side (lower side) or the other axial side (upper side) of the circuit board. Furthermore, the entire circuit board may overlap with the support portion in the axial direction. Other members may be disposed between the circuit board and the support portion in the axial direction. Furthermore, although the embodiment in which the rotation of the rotor is detected by a magnet attached to the shaft and a magnetic sensor mounted on the circuit board has been described, the rotation of the rotor may be detected in any other manner.

[0037] The present technology can be configured as follows. (1) A motor comprising: a shaft extending in the axial direction around a central axis; a rotor rotatable around the shaft; a stator facing the rotor across a gap; a support portion supporting the stator; and a circuit board electrically connected to the stator and switching the current flowing through the stator, wherein the support portion has a bearing that rotatably supports the shaft and a cylindrical portion that supports the bearing on its radially inner surface, the stator is supported on the radially outer surface of the cylindrical portion, the circuit board is located on one axial side of the support portion, and the support portion and at least a portion of the circuit board overlap in the axial direction. (2) The motor according to (1), wherein electronic components are mounted on one axially facing surface of the circuit board. (3) The motor according to (1) or (2), wherein the cylindrical portion has an opening at one end on one axial side of the cylindrical portion, and the circuit board closes at least a part of the opening. (4) The motor according to (3), wherein an electronic component is mounted on a portion of the surface on the other axial side of the circuit board that faces the opening. (5) A motor as described in (4), in which the end of the shaft on one axial side is positioned inside the cylindrical portion, a magnet is attached to the end of the shaft on one axial side, and a magnetic sensor axially facing the magnet is mounted on the surface on the other axial side of the circuit board facing the opening. (6) A motor described in any one of (1) to (5), wherein the support portion has a bottom wall portion that extends radially outward from one axial end of the cylindrical portion, and the circuit board is fixed to one axial side of the bottom wall portion. (7) The motor according to (6), wherein the stator has a winding, the bottom wall portion has a through hole, and a portion of a conductive member connecting the winding and the circuit board is disposed within the through hole. (8) The motor according to any one of (1) to (7), wherein the circuit board has a polygonal shape. (9) A blower comprising the motor according to any one of (1) to (8) and an impeller portion provided on the rotor. [Explanation of symbols]

[0038] 10...blower, 11, 11A, 11B...motor, 13...rotor, 15...impeller portion, 19...shaft, 21...stator, 23...support portion, 25, 25A, 25B...circuit board, 33...winding, 35...cylindrical portion, 35a...opening, 37...bearing, 39...bottom wall portion, 43...through hole, 45...conductive member, 49...electronic component, 49a...magnetic sensor, 51...magnet, J...central axis

Claims

1. a shaft extending axially around a central axis; a rotor rotatable about the shaft; a stator facing the rotor with a gap therebetween; a support portion that supports the stator; a circuit board electrically connected to the stator and configured to switch the current flowing through the stator; Equipped with The support portion is a bearing that rotatably supports the shaft; a cylindrical portion that supports the bearing on a radially inner surface thereof; and the stator is supported on a radially outer surface of the cylindrical portion, the circuit board is located on one axial side of the support portion, The motor, wherein the support portion and at least a portion of the circuit board overlap in the axial direction.

2. 2. The motor according to claim 1, wherein electronic components are mounted on one axial surface of the circuit board.

3. the cylindrical portion has an opening at one axial end of the cylindrical portion, The motor of claim 1 , wherein the circuit board blocks at least a portion of the opening.

4. The motor according to claim 3 , wherein an electronic component is mounted on a portion of the surface on the other axial side of the circuit board that faces the opening.

5. an end portion of the shaft on one side in the axial direction is disposed inside the cylindrical portion, A magnet is attached to one axial end of the shaft, The motor according to claim 4 , wherein a magnetic sensor is mounted on a surface of the other axial side of the circuit board in a portion facing the opening, the magnetic sensor facing the magnet in the axial direction.

6. the support portion has a bottom wall portion that extends radially outward from one axial end of the cylindrical portion, The motor according to claim 1 , wherein the circuit board is fixed to one axial side of the bottom wall portion.

7. the stator has a winding; the bottom wall portion has a through hole, The motor according to claim 6 , wherein a portion of a conductive member connecting the winding and the circuit board is disposed within the through hole.

8. The motor of claim 1 , wherein the circuit board has a polygonal shape.

9. A motor according to any one of claims 1 to 8; an impeller portion provided on the rotor; A blower comprising:

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