Motor

Abstract

Provided is a motor in which an electronic component can be effectively cooled.　A motor (1) comprises: a rotor (40) having a cylinder (41) and blades (431) inside the cylinder (41); a stator (50) surrounding the rotor (40); and a housing (10) surrounding the stator (50). In a rotation axis direction X, the rotor (40) is provided with two ends having a plurality of openings (44H, 412H), and the housing (10) is provided with a fluid suction port and a fluid discharge port.

Description

Motor

[0001] The present invention relates to a motor.

[0002] Conventionally, a motor is known that generates an air flow in the motor by the rotation of a rotor provided with blades on the inside, and can cool electronic components in the motor (for example, see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2002-354751

[0004] However, the motor described in Patent Document 1 circulates the air flow from the center of the electric motor along the inner surface of the bracket. Therefore, the temperature of the air flow circulating in the motor may rise as the motor is driven, and the cooling efficiency of the electronic components in the motor may decrease.

[0005] Therefore, one of the problems of the present invention is to provide a motor capable of cooling electronic components in the motor.

[0006] (1): The motor includes a rotor having a cylinder and blades inside the cylinder, a stator surrounding the rotor, and a housing surrounding the stator. In the axial direction of the rotation axis, the rotor includes two ends having a plurality of openings, and the housing includes a fluid suction port and a fluid discharge port.

[0007] (2): In the motor according to (1), a magnet may be fixed to the outer peripheral surface of the cylinder.

[0008] (3): In the motor according to (1) or (2), a shaft may be provided, and the rotor may be fixed to the shaft.

[0009] (4): In the motor according to any one of (1) to (3), the plurality of openings of the rotor may be a fluid suction port or a fluid discharge port in the housing.

[0010] (5): In the motor according to any one of (1) to (4), the internal space of the cylinder may form a fluid flow path.

[0011] (6) A motor according to any of (1) to (5) may be provided with two bearings, and the rotor may be positioned between the two bearings in the direction of rotation.

[0012] This is a perspective view showing a first embodiment of the motor according to the present invention. This is a cross-sectional view of the motor shown in Figure 1 along the rotation axis direction. This is a cross-sectional view along line A-A in Figure 2. This is a cross-sectional view along line B-B in Figure 2. This is a cross-sectional view along line C-C in Figure 2. This is a perspective view of the rotor and shaft of the motor according to the second embodiment of the present invention, viewed from one side in the rotation axis direction. This is a perspective view of the rotor and shaft shown in Figure 6, viewed from the other side in the rotation axis direction. This is a cross-sectional view of the rotor and shaft shown in Figure 6 along the rotation axis direction.

[0013] The following examples illustrate embodiments of the motor according to the present invention, along with the accompanying drawings. The embodiments illustrated below are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. The present invention can be modified and improved from the following embodiments without departing from its spirit. In addition, in the accompanying drawings, the dimensions of each component may be exaggerated or reduced, or hatching may be omitted, in order to facilitate understanding.

[0014] (First Embodiment) Figure 1 is a perspective view showing the motor 1 in this embodiment. As shown in Figure 1, the motor 1 comprises a housing 10 (motor case), an end cap 20, and a shaft 30 that penetrates the inside (center in this embodiment) of both the housing 10 and the end cap 20. As shown in Figure 2, which will be described later, in the radial direction, the dimension W30 (width) of the shaft 30 is formed to be larger than the thickness W42 of the magnet 42 (difference between the dimension on the outer surface and the dimension on the inner surface) and the dimension W60 of the bearing 60 (difference between the dimension on the outer surface of the outer ring and the dimension on the inner surface of the inner ring), which will be described later, and has a predetermined rigidity. In the longitudinal direction of the shaft 30 (hereinafter referred to as "rotation axis direction X"), the shaft 30 has one end 31 and the other end 32. The one end 31 and the other end 32 are exposed from the housing 10. Although not particularly limited, in this embodiment, in the rotation axis direction X, the portion of the shaft 30 on the side of one end 31 is exposed from the housing 10 for a longer distance than the portion on the side of the other end 32. Hereinafter, for convenience, the side of the end 31 in the rotation axis direction X may be referred to as "upper," "upper side," etc., and the side of the other end 32 in the rotation axis direction X may be referred to as "lower," "lower side," etc., "lower."

[0015] Furthermore, the direction in which a straight line perpendicular to the rotation axis X and passing through the central axis of the shaft 30 extends is called the "radial direction." In addition, within the radial direction, the side relatively closer to the shaft 30 may be referred to as "inside" or "inner," and the side relatively farther from the shaft 30 may be referred to as "outside" or "outer." Also, the circumferential direction of a circle centered on the central axis of the shaft 30 is called the "circumferential direction."

[0016] The housing 10 is a cylindrical (in this embodiment, cylindrical) member extending in the direction of the rotation axis X, and may be formed of a magnetic material such as iron. The housing 10 includes a housing body 11 and a bearing holding portion 12 as a projection or end portion protruding from the housing body 11. The housing body 11 includes a cylindrical side wall 11A extending in the direction of the rotation axis X, and an annular (in this embodiment, circular) annular portion 11B connected to the upper end of the side wall 11A. This annular portion 11B extends radially from the side wall 11A toward the shaft 30 and has a planar shape.

[0017] Figure 2 is a cross-sectional view of the motor 1 along the rotation axis X. As shown in Figure 2, the lower end of the side wall 11A of the housing body 11 is open.

[0018] Figure 3 is a cross-sectional view along line A-A in Figure 2, and Figure 4 is a cross-sectional view along line B-B in Figure 2.

[0019] As shown in Figures 2 and 3, in the rotation axis direction X, one or more openings 13 are formed near the upper end of the side wall 11A (near the annular portion 11B) that penetrate the side wall 11A radially. The number of openings 13 is not particularly limited, but in this embodiment, six openings 13 are formed at equal intervals along the circumferential direction. The shape and dimensions of the openings 13 are also not particularly limited, but in this embodiment, the six openings 13 are formed to be the same shape (oval) and the same dimensions.

[0020] As shown in Figures 2 and 4, in the rotation axis direction X, one or more openings 14 are formed near the lower end of the side wall 11A, penetrating the side wall 11A radially. The number of openings 14 is not particularly limited, but in this embodiment, six openings 14 are formed at equal intervals along the circumferential direction. The shape and dimensions of the openings 14 are also not particularly limited, but in this embodiment, the six openings 14 are formed to be the same shape (oval) and the same dimensions. Furthermore, in this embodiment, as shown in Figure 1, the openings 14 are formed to be approximately the same shape and dimensions as the openings 13, and the circumferential centers of the openings 14 and the circumferential centers of the openings 13 lie on a straight line extending in the rotation axis direction X.

[0021] As shown in Figures 1 and 2, the bearing holder 12 has a cylindrical shape (in this embodiment, a cylindrical shape). The lower end of the bearing holder 12 is open. The bearing holder 12 also has a bottom that forms the upper end, and a part of this bottom has an opening that forms a through hole 12H, which will be described later. The lower end of the bearing holder 12 is connected to the inner peripheral edge of the annular portion 11B of the housing body 11. The upper end 12A of the bearing holder 12 has an annular shape on the radially inner side (center in this embodiment), and a through hole 12H is formed on the inside of this annular upper end. One end (upper end) 31 of the shaft 30 is inserted through this through hole 12H.

[0022] As shown in Figures 1 and 2, the end cap 20 is attached to the lower end (opening) of the housing body 11 of the housing 10. The end cap 20 includes a cylindrical (in this embodiment, cylindrical) first portion 21 having a bottom and a cylindrical (in this embodiment, cylindrical) second portion 22 having a bottom. Here, the upper end of the first portion 21 and the upper end of the second portion 22 are open. The bottom (lower end 21A) of the first portion 21 and the bottom (lower end 22A) of the second portion 22 each have an annular shape that forms an opening. The first portion 21 has a large dimension (diameter in this embodiment), and the second portion 22 has a smaller dimension (diameter in this embodiment) than the first portion 21. The end cap 20 is attached to the housing 10 by fitting the upper end of the first portion 21 into the lower end of the housing body 11. The lower end 21A of the first portion 21 is connected to the lower end of the cylindrical side wall 21B and is formed in an annular shape. The second portion 22 protrudes downward from the inner periphery of the lower end portion 21A. In this embodiment, the lower end portion 21A has an opening 21AH that penetrates the lower end portion 21A in the rotation axis direction X, and the side wall 21B has an opening 21BH that penetrates the side wall 21B in the radial direction. Note that one or both of the openings 21AH and 21BH may not be formed. The lower end portion 22A of the second portion 22 has an annular shape with a through hole 22H in the center in the radial direction. The other end (lower end) 32 of the shaft 30 is inserted through this through hole 22H.

[0023] Figure 5 is a cross-sectional view taken along the line C-C in Figure 2. As shown in Figures 2 to 5, a portion of the shaft 30 (excluding one end 31, the vicinity of the one end 31, the other end 32, and the vicinity of the other end 32 of the shaft 30), the rotor 40, the stator 50, one or more bearings 60, the substrate 70, and the sensor 80 are housed in the space enclosed by the housing 10 and the end cap 20. In other words, the motor 1 includes the housing 10, the end cap 20, and the shaft 30, as well as the rotor 40, the stator 50, one or more bearings 60, the substrate 70, and the sensor 80 provided on the substrate 70.

[0024] As shown in Figure 2, one or more bearings 60 include two bearings 60, 60 (an upper bearing 60 and a lower bearing 60). The bearings 60 are not particularly limited, but in this embodiment, an example is shown where both bearings 60 are ball bearings. Also, the number of bearings 60 is not limited to two. The upper bearing 60 is housed inside the bearing retaining portion 12 of the housing 10 and is supported by the bearing retaining portion 12. The lower bearing 60 is housed inside the second portion 22 of the end cap 20 and is supported by the second portion 22. The shaft 30 passes inside the two bearings 60, 60, and the shaft 30 is rotatably supported by these two bearings 60.

[0025] As shown in Figures 2 to 5, the stator 50 is located outside the rotor 40 and surrounds the rotor 40. On the other hand, the stator 50 is enclosed by the housing 10. The stator 50 includes a stator core 51, an insulator 52 that covers part of the stator core 51, and a plurality of coils 53.

[0026] The stator core 51 may be constructed, for example, by stacking multiple electromagnetic steel sheets (multiple magnetic materials) in the direction of the rotation axis X, or by applying pressure to magnetic iron powder to solidify it. As shown in Figure 5, the stator core 51 includes an annular portion (annular in this embodiment) 511 fixed to the inner circumferential surface 11Aa of the side wall 11A of the housing body 11, a plurality of spokes 512 extending radially inward from the annular portion 511, and protruding portions (magnetic pole portions (salliance poles)) 513 that are connected to the inner ends of each of the plurality of spokes 512 and spread out in the circumferential direction. A so-called tooth is formed by one spoke 512 and one magnetic pole portion 513 connected to the one spoke 512.

[0027] The stator core 51 may be fixed to the housing 10 by fixing, for example, by adhesive, the outer circumferential surface 51B of the annular portion 511 (i.e., the outer circumferential surface 51B of the stator core 51) to the inner circumferential surface 11Aa of the side wall 11A of the housing body 11.

[0028] The inner circumferential surfaces 51A of each of the multiple magnetic pole portions 513 (i.e., the inner circumferential surfaces 51A of the stator core 51) are exposed from the insulator 52.

[0029] Each of the spokes 512 has a conductive coil 53 wound around it via an insulator 52. This insulates the stator core 51 from the coil 53. The coils 53 are electrically connected to a circuit formed on the substrate 70, and power is supplied to the coils 53 through the circuit on the substrate 70.

[0030] As shown in Figure 2, the insulator 52 covers the upper and lower portions of the stator core 51. The upper end portion 52U of the insulator 52 forms the upper end portion of the stator 50. In this embodiment, the lower edge 13D of the opening 13 is at the same position as or above the upper end portion 52U in the rotation axis direction X. Therefore, in the rotation axis direction X, the opening 13 is located between the upper end portion 52U of the insulator 52 and the annular portion 11B of the housing body 11. The lower edge 13D of the opening 13 is at the same position as or above the upper end portion 52U, which allows the opening 13 to communicate entirely with the internal space SP2, which will be described later. In the radial direction, the opening 13 may face the coil 53 or a part of the shaft 30. Also, the upper end portion 52U may be above the lower edge 13D of the opening 13, as long as the opening 13 can communicate with the internal space SP2, which will be described later. In other words, the lower edge 13D of the opening 13 may be positioned below the upper end 52U, and this can be changed as appropriate.

[0031] On the other hand, the lower end portion 52D of the insulator 52 forms the lower end portion of the stator 50. In this embodiment, the upper edge 14U of the opening 14 is at the same position as or below the lower end portion 52D in the rotation axis direction X. In the radial direction, the opening 14 may face the coil 53 or a part of the shaft 30. By having the upper edge 14U of the opening 14 at the same position as or below the lower end portion 52D, the opening 14 can be fully connected to the internal space SP3, which will be described later. Furthermore, as long as the opening 14 can be connected to the internal space SP3, which will be described later, it may be modified as appropriate. For example, the lower end portion 52D may be below the upper edge 14U of the opening 14. In other words, the upper edge 14U of the opening 14 may be above the lower end portion 52D.

[0032] As shown in Figures 2 to 5, the rotor 40 is positioned radially between the shaft 30 and the stator 50. That is, in this embodiment, the shaft 30, rotor 40, stator 50, and housing 10 are arranged radially from the inside out in the order of shaft 30, rotor 40, stator 50, and housing 10. The rotor 40 is also positioned in the rotation axis direction X between the upper bearing 60 and the lower bearing 60.

[0033] The rotor 40 is fixed to the shaft 30 and rotates together with the shaft 30. The rotor 40 includes, for example, a cylinder 41 (rotor yoke) made of a magnetic material, an impeller 43 having a plurality of blades 431 (described later), a magnet 42, and a plate 44.

[0034] The cylinder 41 has a lower end that forms an open bottom 412. The cylinder 41 also has a cylindrical shape (in this embodiment, a cylindrical shape). The cylinder 41 is fixed to the shaft 30 and rotates together with the shaft 30. The cylinder 41 includes a cylindrical side portion 411 extending in the direction of the rotation axis X, a flange 413 protruding outward from the upper end of the side portion 411, and a bottom portion 412 connected to the lower end of the side portion 411.

[0035] As shown in Figures 2 and 3, the flange 413 has an annular shape when viewed from the rotation axis direction X. Although not particularly limited, in this embodiment, in the rotation axis direction X, the upper surface 413U of the flange 413 is in approximately the same position as the upper end 52U of the stator 50. In the radial direction, the inner circumferential surface 413A of the flange 413 forms the opening OP at the upper end of the cylinder 41, and the outer circumferential surface 413B of the flange 413 faces the insulator 52 in the radial direction. Note that the upper surface 413U of the flange 413 may be in a different position (for example, an upper position or a lower position) relative to the upper end 52U of the stator 50.

[0036] As shown in Figures 2 and 4, the bottom portion 412 (lower end of the cylinder 41) has an annular plate shape when viewed from the rotation axis direction X. In this embodiment, the bottom portion 412, together with the lower end portion 42D of the magnet 42, constitutes the lower end of the rotor 40. In the radial direction, a through hole 412PH is formed on the inside of the bottom portion 412 (center in this embodiment), and the bottom portion 412 has an annular shape. The shaft 30 is inserted through the through hole 412PH. The shaft 30 may be press-fitted into the through hole 412PH, for example.

[0037] The bottom portion 412 has one or more openings 412H that penetrate the bottom portion 412 in the direction of the rotation axis X. The number, shape, and dimensions of the openings 412H are not particularly limited. As shown in Figure 4, in this embodiment, three openings 412H are formed. In this embodiment, the shape and dimensions of the three openings 412H are identical except for their position in the circumferential direction. Specifically, each of the three openings 412H has a substantially fan-shaped form in which the outer peripheral edge 412Hb is longer than the inner peripheral edge 412Ha. Furthermore, the inner peripheral edge 412Ha of each of the three openings 412H lies on a first circle C1 centered on the central axis of the shaft 30, and the outer peripheral edge 412Hb of each of the three openings 412H lies on a second circle C2 that is concentric with the first circle C1 and has a larger diameter than the first circle C1. Note that, for convenience, auxiliary dashed lines are shown in Figure 4 to indicate the first circle C1 and the second circle C2.

[0038] Furthermore, in this embodiment, since the three openings 412H described above are formed in the bottom portion 412, the bottom portion 412 includes an inner first annular portion 412A, an outer second annular portion 412B, and three spokes 412C extending radially outward from the first annular portion 412A. The first annular portion 412A and the second annular portion 412B are connected by the three spokes 412C. A through hole 412PH is formed by the inner periphery of the first annular portion 412A.

[0039] As shown in Figures 2 and 3, the plate 44 is located slightly below the flange 413 and, together with the flange 413, constitutes the upper end of the rotor 40. The plate 44 is fixed to the shaft 30 and rotates with the shaft 30. The plate 44 has an annular plate shape when viewed from the rotation axis direction X, and extends radially from the outer circumferential surface of the shaft 30 toward the inner circumferential surface 411A of the side portion 411 of the cylinder 41. The plate 44 may be fixed to the cylinder 41. In the radial direction, an annular through hole 44PH is formed in the center of the plate 44. The shaft 30 is inserted through the through hole 44PH. The shaft 30 may be press-fitted into the through hole 44PH, for example.

[0040] The plate 44 has one or more openings 44H that penetrate the plate 44 in the direction of the rotation axis X. The number, shape, and dimensions of the openings 44H are not particularly limited. As shown in Figure 3, in this embodiment, three openings 44H are formed. In this embodiment, the shape and dimensions of the three openings 44H are the same except for their position in the circumferential direction. Specifically, each of the three openings 44H has a substantially fan-shaped form in which the outer peripheral edge 44Hb is longer than the inner peripheral edge 44Ha. Furthermore, the inner peripheral edge 44Ha of each of the three openings 44H lies on a third circle C3 centered on the central axis of the shaft 30, and the outer peripheral edge 44Hb of each of the three openings 44H lies on a fourth circle C4 that is concentric with the third circle C3 and has a larger diameter than the third circle C3. Note that in Figure 3, dashed auxiliary lines are shown for convenience to indicate the third circle C3 and the fourth circle C4.

[0041] Furthermore, in this embodiment, since the plate 44 has the three openings 44H described above, the plate 44 includes an inner first annular portion 44A, an outer second annular portion 44B, and three spokes 44C extending radially outward from the first annular portion 44A. The first annular portion 44A and the second annular portion 44B are connected by the three spokes 44C. A through hole 44PH is formed by the inner periphery of the first annular portion 44A.

[0042] As shown in FIGS. 2 and 5, the magnet 42 has a cylindrical (in this embodiment, circular cylindrical) shape. The magnet 42 is formed by alternately magnetizing N poles and S poles along the circumferential direction on the outer peripheral surface 42B of the magnet 42. The outer peripheral surface 42B of the magnet 42 is inside the inner peripheral surface 51A of the stator core 51 and faces the inner peripheral surface 51A of the stator core 51 through an air gap in the radial direction.

[0043] The magnet 42 is fixed to the cylinder 41, for example, by adhesion, such that the inner peripheral surface 42A of the magnet 42 contacts the outer peripheral surface of the side portion 411 of the cylinder 41 and a part of the upper surface of the magnet 42 contacts the lower surface of the flange 413 of the cylinder 41. That is, the magnet 42 is fixed to the outer peripheral surface of the cylinder 41. The lower end portion 42D of the magnet 42 is below the bottom portion 412 of the cylinder 41 and the lower end portion 52D of the insulator 52, and together with the bottom portion 412 of the cylinder 41, constitutes the lower end portion of the rotor 40 as described above. Note that the position of the lower end portion 42D of the magnet 42 is not limited to this, and may be, for example, at the position of the bottom portion 412 in the rotational axis direction X, or may be above the bottom portion 412.

[0044] As shown in FIGS. 2 and 5, the impeller 43 is fixed to the shaft 30 and rotates together with the shaft 30. The impeller 43 extends in the rotational axis direction X and has a cylindrical (in this embodiment, circular cylindrical) shape with openings at the upper end portion and the lower end portion. The impeller 43 is housed inside the cylinder 41 and is between the plate 44 and the bottom portion 412 of the cylinder 41 in the rotational axis direction X.

[0045] The impeller 43 includes a cylindrical portion 432 and one or more blades 431. The cylindrical portion 432 has a circular cylindrical shape with openings at the upper end portion and the lower end portion, and has a length slightly smaller than the length between the plate 44 and the bottom portion 412 of the cylinder 41 in the rotational axis direction X.

[0046] The blades 431 are provided on the outer circumferential surface of the cylindrical portion 432. That is, the inner circumferential edge 431B of the blades 431 is on the outer circumferential surface of the cylindrical portion 432. On the other hand, the outer circumferential edge 431A of the blades 431 faces the inner circumferential surface 411A of the side portion 411 of the cylinder 41 with a small gap in the radial direction. That is, the blades 431 are inside the cylinder 41. The number, shape, and dimensions of the blades 431 are not particularly limited. In this embodiment, three blades 431 are provided. Also in this embodiment, the three blades 431 are formed to be substantially the same shape and dimensions except for their position in the circumferential direction. The blades 431 extend in a curved manner from near the upper end to near the lower end of the cylindrical portion 432 in the rotation axis direction X.

[0047] As shown in Figure 5, in this embodiment, each of the three blades 431 is formed in a substantially fan shape in a cross-section along the radial direction, where the length of the outer peripheral edge 431A is longer than the length of the inner peripheral edge 431B. Furthermore, in a cross-section along the radial direction, each of the three blades 431 is formed in a substantially rectangular shape, with each cut surface 431E extending radially to the vicinity of the inner peripheral surface 411A. The cut surfaces 431E of the three blades 431 are arranged at approximately equal intervals in the circumferential direction (i.e., at approximately 120° intervals). In addition, in a cross-section along the radial direction, each of the outer peripheral edges 431A of the three blades 431 forms part of a circle concentric with the circle formed by the inner peripheral surface 411A (a circle centered on the central axis of the shaft 30). Furthermore, as shown in Figure 5, the three blades 431 are formed so as not to overlap each other when viewed from the direction of the rotation axis X. As shown in Figure 2, the three blades 431 are positioned in the rotation axis direction X, facing the upper bearing 60 via the plate 44. The three blades 431 also face the lower bearing 60 in the rotation axis direction X, via the bottom 412 of the cylinder 41 and the base plate 70.

[0048] As shown in FIG. 2, the substrate 70 is fitted into the opening at the upper end of the first portion 21 of the end cap 20, closing the opening. The substrate 70 has an inner peripheral portion and is formed in an annular shape. A hole 70H penetrating the substrate 70 in the rotational axis direction X is formed inside the substrate 70 (at the center in this embodiment) in the radial direction, and the shaft 30 is inserted through this hole 70H. In the rotational axis direction X, the above-described opening 14 is formed at a position slightly above or at the same position as the substrate 70. Therefore, in the rotational axis direction X, the opening 14 of the housing 10 is between the substrate 70 and the lower end portion 52D of the insulator 52. Note that a part of the substrate 70 and a part of the opening 14 may overlap in the rotational axis direction X, the opening 14 may be disposed above or below the lower end portion 52D of the insulator 52, or may be disposed above or below the substrate 70. However, by forming the opening 14 at a position slightly above or at the same position as the substrate 70 in the rotational axis direction X, the opening 14 can be entirely communicated with an internal space SP3 described later. The substrate 70 may be provided with a connector connected to an external power source, various electronic components, various wirings, and one or more sensors 80 (e.g., Hall elements) capable of detecting the position of the rotor 40. Also, a part of the wirings provided on the substrate 70 electrically connects the plurality of coils 53 and the external power source. In the present embodiment, an opening 70Ha penetrating the substrate 70 in the rotational axis direction X is formed in the substrate 70. However, the opening 70Ha does not necessarily have to be formed.

[0049] In such a motor 1, when current flows through the plurality of coils 53, a magnetic interaction occurs between the inner peripheral surface 51A of the stator core 51 and the outer peripheral surface 42B of the magnet 42 facing each other through the air gap, and the rotor 40 rotates together with the shaft 30 with respect to the stator 50, the housing 10, the substrate 70, etc. That is, the blades 431 housed in the internal space of the cylinder 41 of the rotor 40 (specifically, the internal space SP1 between the plate 44 and the bottom portion 412 in the internal space of the cylinder 41 as shown in FIG. 2) rotate around the shaft 30. Then, due to the rotation of the blades 431, an air flow (fluid) is generated in the internal space SP1 of the cylinder 41.

[0050] Here, as shown in Figure 2, an internal space SP2 is formed in the upper part of the motor 1. This internal space SP2 is a space enclosed by the part of the housing 10 above the upper end 52U of the insulator 52, the upper end 52U of the insulator 52, the upper surface 413U of the flange 413 of the cylinder 41, the lower surface 60D of the upper bearing 60, a part of the outer circumferential surface of the shaft 30, a part of the inner circumferential surface 411A of the cylinder 41 (the upper part), and the plate 44. The opening 13 formed in the upper part of the housing 10 is in communication with the internal space SP2. Therefore, in the internal space SP2, the opening 13 formed in the housing 10 is an inlet (suction port) or outlet (discharge port) for airflow (fluid) to the outside of the motor 1, and the opening 44H formed in the plate 44 is an inlet (suction port) or outlet (discharge port) for airflow (fluid) to the internal space SP1 within the housing 10.

[0051] Furthermore, as shown in Figure 2, an internal space SP3 is formed in the lower part of the motor 1. This internal space SP3 is a space enclosed by the portion of the housing 10 below the lower end 52D of the insulator 52, the lower end 52D of the insulator 52, the lower part of the magnet 42 including the lower end 42D, the bottom 412 of the cylinder 41, a part of the outer circumferential surface of the shaft 30, and the substrate 70. The opening 14 formed in the lower part of the housing 10 communicates with the internal space SP3. Therefore, in the internal space SP3, the opening 14 formed in the housing 10 is an inlet (suction port) or outlet (discharge port) for airflow (fluid) to the outside of the motor 1, and the opening 412H formed in the bottom 412 is an inlet (suction port) or outlet (discharge port) for airflow (fluid) to the internal space SP1 within the housing 10.

[0052] Furthermore, in this embodiment, as described above, an opening 70Ha may be formed in the substrate 70 and openings 21AH and 21BH may be formed in the end cap 20 as needed. Therefore, the internal space SP3 communicates with the space inside the end cap 20 via the opening 70Ha. The space inside the end cap 20 communicates with the outside via the openings 21AH and 21BH. Thus, the openings 21AH and 21BH formed in the end cap 20 function as an inlet (suction port) or outlet (discharge port) for airflow (fluid) to the outside in the motor 1. Moreover, since the openings 21AH and 21BH are located on the lower side of the motor 1, they function together with the opening 14 as an inlet (suction port) or outlet (discharge port) for airflow (fluid) to the outside on the lower side of the motor 1. On the other hand, since the opening 13 is located on the upper side of the motor 1, it functions as an inlet (suction port) or outlet (discharge port) for airflow (fluid) to the outside on the upper side of the motor 1. In the rotation axis direction X, the opening 13 is located on one end 31 of the shaft 30 relative to the upper end of the rotor 40. In the radial direction, the opening 13 is positioned outward relative to the upper bearing 60 (in other words, the upper bearing 60 is positioned inward relative to the opening 13). The sensor 80 is positioned facing the opening 13 in the radial direction.

[0053] As described above, when an airflow (fluid) is generated in the internal space SP1 of the cylinder 41, this airflow flows both outside and inside the motor 1. Specifically, a fluid flow path FP is formed inside the motor 1, through which the fluid is drawn in from one of the upper opening 13 and the lower openings 14, 21AH, and 21BH, passes through one of the internal spaces SP2 and SP3, flows through the internal space SP1, and then passes through the other internal space SP2 and SP3 before being discharged to the outside from the other of the upper opening 13 and the lower openings 14, 21AH, and 21BH. For convenience, the schematic of the flow path FP is shown with a dashed line in Figure 2. In other words, in the motor 1, the internal space SP1 of the cylinder 41 forms a fluid flow path FP that flows between the outside and inside of the motor 1.

[0054] As described above, the motor 1 comprises a rotor 40 having a cylinder 41 and blades 431 inside the cylinder 41, a stator 50 surrounding the rotor 40, and a housing 10 surrounding the stator 50. In the rotation axis direction X, the rotor 40 has two ends (a plate 44 with opening 44H and a bottom 412 with opening 412H) having a plurality of openings 44H and 412H, and the housing 10 has a fluid intake port (one of openings 13 and 14) and a fluid discharge port (the other of openings 13 and 14). In the rotation axis direction X, opening 14 is located on the other end 32 side of the shaft 30 relative to the lower end of the rotor 40. In the radial direction, opening 14 is positioned outward relative to the lower bearing 60 (in other words, the lower bearing 60 is positioned inward relative to opening 14). The sensor 80 is positioned facing opening 14 in the radial direction. Furthermore, the lower end of the magnet 42 is positioned opposite the opening 14.

[0055] In this motor 1, the airflow (fluid) generated by the rotation of the blades 431 flows through the openings 13 and 14 of the housing 10 and the openings 44H and 412H of the rotor 40, circulating both inside and outside the motor 1. Therefore, even when the motor 1 is driven for a long time or at high speeds, the temperature of the fluid flowing inside the motor 1 is prevented from rising, and the electronic components (e.g., multiple coils 53) inside the motor 1 can be cooled.

[0056] (Second Embodiment) Next, a motor according to the second embodiment will be described. The motor of this embodiment has the same configuration as the motor 1 of the first embodiment, except that a part of the rotor is different from the rotor 40 of the first embodiment. Therefore, only the differences from the motor 1 of the first embodiment will be described below, and other components will be denoted by the same reference numerals as in the first embodiment and their descriptions will be omitted.

[0057] Figure 6 is a perspective view of the rotor 400 and shaft 30 of the motor 2 according to the second embodiment, viewed from one side in the rotation axis direction X. Figure 7 is a perspective view of the rotor 400 and shaft 30 of the motor 2, viewed from the other side in the rotation axis direction X. Figure 8 is a cross-sectional view of the rotor 400 and shaft 30 of the motor 2 along the rotation axis direction. As described above, the motor 2 has the same configuration as the motor 1, except that a part of the rotor 400 is different from the rotor 40. That is, the motor 2, like the motor 1, has a housing 10, an end cap 20, a shaft 30, a stator 50, two bearings 60, and a base plate 70. Therefore, in Figures 6 to 8, the housing 10, end cap 20, stator 50, two bearings 60, and base plate 70 are omitted from the illustration, and only the shaft 30 and rotor 400 are shown.

[0058] As shown in Figures 6 to 8, the rotor 400 of motor 2 includes a plate 440 having a different configuration from the plate 44 of rotor 40, and a bottom 4412 of cylinder 4411 having a different configuration from the bottom 412 of cylinder 41 of rotor 40. In this respect, the rotor 400 of motor 2 differs from the rotor 40 of motor 1, but in other respects, the rotor 400 has the same configuration as rotor 40.

[0059] As shown in Figures 6 and 8, the plate 440 of the rotor 400 is located slightly below the flange 413 of the rotor 400 and, together with the flange 413, constitutes the upper end of the rotor 400. The plate 440 is fixed to the shaft 30 and rotates with the shaft 30. The plate 440 has an annular plate shape when viewed from the rotation axis direction X, and extends radially from the outer circumferential surface of the shaft 30 to the inner circumferential surface of the side portion 411 of the cylinder 4411 of the rotor 400. Radially, an inner circumferential portion and a through hole 44PH surrounded by the inner circumferential portion are formed on the inside of the plate 440 (center in this embodiment). The shaft 30 is inserted through the through hole 44PH. The shaft 30 may be press-fitted into the through hole 44PH, for example.

[0060] The plate 440 has one or more openings 440H that penetrate the plate 440 in the rotation axis direction X. The number, shape, and dimensions of the openings 440H are not particularly limited. In this embodiment, six openings 440H are formed. In this embodiment, the shape and dimensions of the six openings 440H are the same except for their position in the circumferential direction. Specifically, each of the six openings 440H has a substantially fan-shaped form in which the outer peripheral edge 440Hb is longer than the inner peripheral edge 440Ha. In each of the six openings 440H, the two side edges 440Hc and 440Hd that connect the inner peripheral edge 440Ha and the outer peripheral edge 440Hb extend linearly along the radial direction and face each other in the circumferential direction.

[0061] Each of the six openings 440H is provided with a blade 441 that extends diagonally from the side edge 440Hc upward toward the side edge 440Hd. The upper end 441U of the blade 441 is below the flange 413 of the cylinder 4411. Therefore, each of the six blades 441 is located inside the cylinder 4411. Thus, in this embodiment, the blades 441 are provided on the plate 440 which is the upper end of the rotor 400, and the plate 440 forms a so-called impeller. In this respect, the rotor 400 differs from the rotor 40 in which the impeller 43 is provided inside the cylinder 41. Note that the upper end 441U of the blade 441 may be at the same position as or above the flange 413 of the cylinder 4411.

[0062] In this embodiment, an example in which the blade 441 faces upward has been described, but the blade 441 may also be formed to face downward, that is, to face the internal space SP1.

[0063] As shown in Figures 7 and 8, the bottom portion 4412 of the cylinder 4411 has an annular plate shape when viewed from the direction of the rotation axis X. In this embodiment, the bottom portion 4412 is located slightly above the lower end portion 42D of the magnet 42 and together with the lower end portion 42D of the magnet 42 constitutes the lower end of the rotor 400. In the radial direction, an inner circumference and a through hole 412PH surrounded by the inner circumference are formed in the center of the bottom portion 4412. The shaft 30 is inserted through the through hole 412PH. The shaft 30 may be press-fitted into the through hole 412PH, for example.

[0064] The bottom portion 4412 has one or more openings 4412H that penetrate the bottom portion 4412 in the rotation axis direction X. The number, shape, and dimensions of the openings 4412H are not particularly limited. In this embodiment, six openings 4412H are formed. In this embodiment, the shape and dimensions of the six openings 4412H are the same except for their position in the circumferential direction. Specifically, each of the six openings 4412H has a substantially fan-shaped form in which the outer peripheral edge 4412Hb is longer than the inner peripheral edge 4412Ha. In each of the six openings 4412H, the two side edges 4412Hc and 4412Hd that connect the inner peripheral edge 4412Ha and the outer peripheral edge 4412Hb extend linearly along the radial direction and face each other in the circumferential direction.

[0065] Each of the six openings 4412H is provided with one or more blades 4413 extending diagonally downward from the side edge 4412Hc toward the side edge 4412Hd. The lower end 4413D of the blade 4413 is above the lower end 42D of the magnet 42. Here, the cylindrical magnet 42 is fixed to the outer surface of the cylindrical tube 4411. Therefore, if the magnet 42 and the tube 4411 are considered together as the tube 4450 of the rotor 400, the blade 4413, whose lower end 4413D is above the lower end 42D of the magnet 42, is located inside the tube 4450. Thus, in this embodiment, the blade 4413 is provided at the bottom 4412 of the tube 4411, which is the lower end of the rotor 400. In this respect, the rotor 400 differs from the rotor 40 in which blades 431 are provided on an impeller 43 fixed to the shaft 30. The lower end portion 4413D of the blade 4413 may be positioned at the same location as or below the lower end portion 42D of the magnet 42.

[0066] In this embodiment, an example in which the blade 4413 faces downwards has been described. However, the blade 441 may be formed so that the blade 4413 faces upwards, that is, so that it faces the internal space SP1. In this case, the blade 4413 is located inside the cylinder 4411.

[0067] As described above, the motor 2 comprises a rotor 400 having a cylinder 4411 (or cylinder 4450) and blades 441 and 4413 located inside the cylinder 4411 (or cylinder 4450), a stator 50 surrounding the rotor 400, and a housing 10 surrounding the stator 50. In the rotation axis direction X, the rotor 400 has two ends (a plate 440 with an opening 440H and a bottom 4412 with an opening 4412H) having a plurality of openings 440H and 4412H, and the housing 10 has a fluid intake port (one of the openings 13 and 14) and a fluid discharge port (the other of the openings 13 and 14).

[0068] With this motor 2, the airflow (fluid) generated by the rotation of the blades 441 and 4413 flows through the openings 13 and 14 of the housing 10 and the openings 440H and 4412H of the rotor 400, circulating between the inside and outside of the motor 2. As a result, the airflow does not stagnate inside the motor 2. Therefore, even when the motor 2 is driven for a long time or at high speeds, the temperature of the fluid flowing inside the motor 2 does not rise, and the electronic components (e.g., multiple coils 53) inside the motor 2 can be effectively cooled.

[0069] In this embodiment, an example in which blades are provided on both the plate 440 and the bottom portion 4412 has been described. However, as a modification of the second embodiment, blades may be provided on only one of the plate 440 or the bottom portion 4412.

[0070] Although the present invention has been described above with reference to the first and second embodiments, the present invention is not limited thereto.

[0071] For example, the first embodiment and the second embodiment may be used in combination. Specifically, the impeller 43 may be provided on the shaft 30, the blades 441 on the plate 440, and the blades 4413 on the bottom 4412. Alternatively, the impeller 43 may be provided on the shaft 30, and only one of the blades 441 and the blades 4413 may be provided.

[0072] Those skilled in the art can modify the motor of the present invention as appropriate in accordance with conventionally known knowledge. Such modifications, insofar as they still possess the configuration of the present invention, are of course included within the scope of the present invention.

[0073] 1, 2...Motor, 10...Housing, 13, 14...Opening (suction port or discharge port), 30...Shaft, 40, 400...Rotor, 41, 4411, 4450...Cylinder, 42...Magnet, 44H, 412H, 440H, 4412H...Opening, 44...Plate (end), 50...Stator, 60...Bearing, 412...Bottom (end), 431, 441, 4413...Blades, SP1...Internal space, FP...Flow path

Claims

1. A motor comprising: a rotor having a cylinder and blades inside the cylinder; a stator surrounding the rotor; and a housing surrounding the stator, wherein in the direction of rotation, the rotor has two ends having a plurality of openings, and the housing has a fluid intake port and a fluid discharge port.

2. The motor according to claim 1, wherein a magnet is fixed to the outer surface of the cylinder.

3. The motor according to claim 1 or 2, comprising a shaft, wherein the rotor is fixed to the shaft.

4. The motor according to any one of claims 1 to 3, wherein the plurality of openings of the rotor are fluid suction ports or fluid discharge ports within the housing.

5. The motor according to any one of claims 1 to 4, wherein the internal space of the cylinder forms a fluid passage.

6. The motor according to any one of claims 1 to 5, comprising two bearings, wherein the rotor is positioned between the two bearings in the direction of rotation.

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