Motor

Abstract

A motor (1) comprises: a stator (6) that has a plurality of coils; a busbar (8) that is provided on the inner circumferential side of the stator (6) so as to be connected to the coils (62); and a heat sink (9) that is provided on the inner circumferential side of the busbar (8) so as to contact the busbar (8). The busbar (8) is electrically insulated from the heat sink (9).

Description

Motor

[0001] The present invention relates to a motor.

[0002] For example, Patent Document 1 discloses a motor including a stator and a rotor rotatably supported by the stator. The stator has coils wound around respective teeth of a stator core.

[0003] JP 2018-107958 A

[0004] When current is supplied to the coils, the coils generate heat. Since the resistance value of the coils rises due to the temperature increase caused by heat generation, the efficiency of the motor decreases. Therefore, it is necessary to suppress the temperature increase caused by heat generation of the coils as much as possible.

[0005] The present invention has been made in view of the above problems, and an example of the problem is to provide a motor capable of efficiently dissipating heat from coils.

[0006] A motor according to one aspect of the present invention includes: a stator having a plurality of coils; a bus bar disposed on an inner peripheral side of the stator and connected to the coils; and a heat sink disposed on an inner peripheral side of the bus bar and in contact with the bus bar, wherein the bus bar is electrically insulated from the heat sink.

[0007] FIG. 2 is a perspective view schematically showing a partial structure of a motor 1 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. FIG. 3 is an exploded perspective view schematically showing a structure of a stator 6 according to a specific example. FIG. 3 is a perspective view schematically showing a structure of a stator assembly 3 according to a specific example. FIG. 3 is an exploded perspective view schematically showing the structure of the stator assembly 3 according to the specific example. FIG. 3 is a plan view schematically showing the structure of the stator assembly 3 according to the specific example. FIG. 8 is a partially enlarged cross-sectional view taken along line 8-8 in FIG. 7.

[0008] One embodiment of the present invention will be described below with reference to the attached drawings. Figure 1 is a schematic perspective view showing a part of the structure of a motor 1 according to one embodiment of the present invention. This motor 1 is, in one example, a motor mounted on an unmanned aerial vehicle, including a multicopter. The motor 1 is attached, for example, to the ends of multiple arms extending from the body of the unmanned aerial vehicle. One or more propellers are attached to the rotor of the motor 1. Thrust and lift are generated in the unmanned aerial vehicle by the rotation of the rotor, i.e., the propellers, around the rotation axis x.

[0009] In the following explanation, the terms "up" and "down" are used for convenience in the direction along the rotation axis x (hereinafter referred to as the "axial direction"). However, the terms "up" and "down" do not necessarily correspond to up and down in the direction of gravity, and are defined as up and down for convenience when considering the motor 1 alone. Furthermore, the direction perpendicular to the rotation axis x is defined as the radial direction, and the direction away from the rotation axis x or approaching the rotation axis x in the radial direction is defined as the outer circumference side or the inner circumference side, respectively. In addition, the direction around the rotation axis x is defined as the circumferential direction.

[0010] Figure 2 is a cross-sectional view along line 2-2 in Figure 1. Figure 3 is a cross-sectional view along line 3-3 in Figure 2. Referring together to Figures 1 to 3, the motor 1 comprises a frame 2, a stator assembly 3, a shaft 4, and a rotor 5. The stator assembly 3 is fixed to the frame 2. The rotor 5 is fixed to the shaft 4. In this example, the shaft 4 is formed in a cylindrical shape with the axis of rotation x as its central axis. The shaft 4 is supported by the frame 2 so as to be rotatable around the axis of rotation x via, for example, two bearings 11. In this example, the bearings 11 are ball bearings, but other types of bearings may be used. The motor 1 is also attached, for example, to an attachment on the arm of an unmanned aerial vehicle on, for example, the underside of the frame 2.

[0011] Frame 2 is formed in an annular shape around the axis of rotation x as a whole. Frame 2 has a base 21, a first sleeve 22, and a second sleeve 23, all of which are formed annularly around the axis of rotation x. The base 21, the first sleeve 22, and the second sleeve 23 are integrally formed from, for example, a metal material (e.g., aluminum) or a resin material. The base 21 has a first portion 24 that extends along a plane perpendicular to the axis of rotation x, and a second portion 25 that inclins upward in the axial direction as it extends radially outward from the first portion 24. The first portion 24 and the second portion 25 are each formed annularly around the axis of rotation x in a plan view in the axial direction.

[0012] In particular, as shown in Figure 3, the first portion 24 has one or more (eight in this example) through holes 26 that penetrate the first portion 24 in the axial direction. The eight through holes 26 are arranged in the circumferential direction. The second portion 25 also has one or more (eight in this example) through holes 27 that penetrate the second portion 25 in the axial direction. The eight through holes 27 are arranged in the circumferential direction. These through holes 26 and 27 are used as air passages between the internal and external spaces of the motor 2, or as spaces for passing wiring into the motor 2. The first portion 24 also has a plurality of screw holes 28 for fixing the frame 2 to the attachment of the unmanned aircraft. The screw holes 28 are holes with an inner surface in which a helical groove is formed.

[0013] The first sleeve 22 is a wall integrally formed on the outer circumference end of the second portion 25 of the base 21. In one example, the first sleeve 22 is formed in a cylindrical shape centered on the axis of rotation x. The stator assembly 3 is fixed to the outer circumference surface of the first sleeve 22. The second sleeve 23 is a wall integrally formed on the inner circumference end of the first portion 24 of the base 21. In one example, the second sleeve 23 is formed in a cylindrical shape centered on the axis of rotation x. The outer rings of the two bearings 11, 11 described above are supported on the inner circumference surface of the second sleeve 23, for example by press-fitting. The shaft 4 is supported on the inner rings of the two bearings 11, 11, for example by press-fitting.

[0014] An annular internal space is formed between the inner surface of the first sleeve 22 and the outer surface of the second sleeve 23, with respect to the axis of rotation x. In the radial direction, through holes 26 and 27 are formed in the base 21 between the inner surface of the first sleeve 22 and the outer surface of the second sleeve 23, so this internal space is connected to the external space of the motor 2 via the through holes 26 and 27. Therefore, as will be described later, as the rotor 5 rotates relative to the frame 2 with respect to the axis of rotation x, outside air is introduced into this internal space from the external space via the through holes 26 and 27, and outside air is discharged from this internal space to the external space.

[0015] As shown in Figure 2, a disc-shaped pusher 29 is attached to the lower end of the second sleeve 23, for example, by screwing it in. By adjusting the amount of screwing the pusher 29 into the second sleeve 23 in the axial direction, the pusher 29 applies a predetermined preload upward in the axial direction to the outer ring of the bearing 11, which is positioned lower in the axial direction. On the other hand, a projection 23a that protrudes annularly inward from the inner circumferential surface of the second sleeve 23 applies a predetermined preload downward in the axial direction to the outer ring of the bearing 11, which is positioned upper in the axial direction. In this way, the shaft 4 is supported by the two bearings 11, 11 in the second sleeve 23 so as to be rotatable around the rotation axis x.

[0016] The stator assembly 3 is formed in an annular shape around the axis of rotation x. In one example, the stator assembly 3 includes a stator 6, a substrate 7, busbars 8, and a heat sink 9. The stator 6, substrate 7, and busbars 8 are all formed in an annular shape around the axis of rotation x. On the other hand, as will be described later, in one example, the heat sink 9 extends in an arc shape over a predetermined angle in the circumferential direction. The stator assembly 3 is fixed to the frame 2 by fixing the stator 6 to the outer circumferential surface of the first sleeve 22. That is, the stator 6 is located on the outer circumferential side of the first sleeve 22.

[0017] In this example, the circuit board 7 is attached to the upper end of the stator 6. When the stator 6 is attached to the outer surface of the first sleeve 22, the circuit board 7 is positioned across the upper end of the first sleeve 22, from the outer surface to the inner surface. The busbars 8 and heatsink 9 are positioned on the inner surface of the circuit board 7. In this example, the heatsink 9 is fixed to the inner surface of the busbars 8. Thus, the busbars 8 and heatsink 9 are positioned on the inner surface of the first sleeve 22. That is, the heatsink 9 is positioned in the internal space between the inner surface of the first sleeve 22 and the outer surface of the second sleeve 23.

[0018] The stator 6 comprises a stator core (magnetic material) 61, a plurality of coils 62, and an insulator 63. The stator core 61 is formed from a laminate (magnetic material) of multiple, for example, annular electromagnetic steel sheets, and functions as a yoke for the stator assembly 3. The inner circumferential surface of the stator core 61 is fixed to the outer circumferential surface of the first sleeve 22. As will be described later, the coils 62 are wound around each spoke of the stator core 61. The insulator 63 is placed between the stator core 61 and the coils 62. In this way, electrical insulation is established between the stator core 61 and the coils 62. The substrate 7 is provided on the insulator 63 that covers the stator core 61. Details of the stator assembly 3 will be described later.

[0019] On the other hand, the rotor 5 includes a housing 51, a yoke 52, and a magnet 53. The housing 51 is integrally formed with the shaft 4. The housing 51 extends radially outward from the upper end of the shaft 4. One or more blades 54 are formed on the inner surface (bottom surface) of the housing 51. The housing 51 is made of a disc-shaped plate material that slopes downward towards the outer circumference. The housing 51 does not have through holes or openings, and has a continuous surface that covers the opening at the upper end of the yoke 52. Each blade 54 is, for example, a plate material, spoke, or rod that extends along a plane containing the axis of rotation x. The blades 54 can generate airflow in the internal space of the motor 2 when the rotor 5 rotates.

[0020] A generally cylindrical yoke 52 is formed at the outer peripheral end of the housing 51. A cylindrical magnet 53 is attached to the inner circumferential surface of the yoke 52. The yoke 52 is made of a magnetic material, for example. The magnet 53 is a permanent magnet, for example. In this example, the magnet 53 is made of two cylindrical permanent magnets stacked vertically in the axial direction. The inner circumferential surface of the magnet 53 faces the outer circumferential surface of the stator core 61. The inner circumferential surface of the magnet 53 and the outer circumferential surface of the stator core 61 face each other with a predetermined space between them. This space forms a predetermined magnetic gap in the radial direction.

[0021] Multiple wires 12 are held on the underside of the base 21 of the frame 2. These wires 12 pass through, for example, through holes 26 or 27 of the base 21 and are electrically connected to multiple coils 62 via busbars 8 of the stator assembly 3. In this way, current is supplied to the coils 62 from a battery, for example, built into the main body of the unmanned vehicle. When current is supplied to the coils 62, a magnetic interaction is generated between the coils 62 and the magnet 53. This magnetic interaction allows the rotor 5 to rotate around the axis of rotation x. In this example, the motor 1 is a so-called outer rotor type motor in which the rotor 5 surrounds the stator 6.

[0022] The stator core 61 of the stator 6 has an annular portion 61a formed in an annular shape with the rotation axis x as its center, a plurality of (24 in this example) magnetic pole portions 61b arranged in the circumferential direction around the rotation axis x, and spokes 61c connecting the annular portion 61a and the magnetic pole portions 61b to each other. The annular portion 61a is formed in a cylindrical shape with the rotation axis x as its central axis. Each spoke 61c protrudes radially outward from the outer circumferential surface of the annular portion 61a. The magnetic pole portions 61b protrude circumferentially from the outer circumferential ends of the spokes 61c. The magnetic pole portions 61b are integrally formed with the outer circumferential ends of the spokes 61c.

[0023] A so-called tooth is formed by the magnetic pole portion 61b and the spoke 61c. The conductor 62a forming the coil 62 is wound around each spoke 61c in a clockwise or counterclockwise direction around a winding axis defined in the radial direction. An insulator 63 is placed between the spoke 61c and the coil 62. The insulator 63 is made of an insulating material, such as a resin material. The insulator 63 may be integrally formed with the stator core 61 by insert molding, for example. In this way, the spoke 61c, i.e., the stator core 61, and the conductor 62a of the coil 62 are electrically insulated from each other.

[0024] Figure 4 is an exploded perspective view schematically showing the structure of a stator 6 according to one specific example. Note that the coil 62 is not shown in Figure 4. Referring together to Figures 2 to 4, the stator core 61 has a first divided core 61A and a second divided core 61B that can be divided in the axial direction. In this example, the first divided core 61A is positioned above the second divided core 61B in the axial direction. The first divided core 61A has an annular first portion A1, a plurality of first magnetic pole portions A2, and a plurality of first spokes A3 that connect the first portion A1 and the plurality of first magnetic pole portions A2. Similarly, the second divided core 61B has an annular second portion B1, a plurality of second magnetic pole portions B2, and a plurality of second spokes B3 that connect the second portion B1 and the plurality of second magnetic pole portions B2.

[0025] In the first segmented core 61A, twelve first spokes A3 extend from the first portion A1 outward. The twelve first spokes A3 are arranged at equal intervals in the circumferential direction. A portion of the first segmented core 61A is covered by the first insulator 63A. Specifically, the first insulator 63A has one upper portion A4 that covers the upper half of the first portion A1, each first spoke A3, and each first magnetic pole portion A2, and twelve lower portions A5 that cover the lower portions of each first spoke A3 and each first magnetic pole portion A2. Both the upper portion A4 and the lower portions A5 are resin films integrally formed on the first segmented core 61A, for example by insert molding. The first insulator 63A electrically insulates the coil 62 wound around the first spokes A3 from the first spokes A3.

[0026] On the other hand, in the second divided core 61B, twelve second spokes B3 extend from the second portion B1 outward. The twelve second spokes B3 are arranged at equal intervals in the circumferential direction. A part of the second divided core 61B is covered by the second insulator 63B. Specifically, the second insulator 63B has one lower portion B4 that covers the lower half of the second portion B1, each second spoke B3, and each second magnetic pole portion B2, and twelve upper portions B5 that cover the upper portions of each second spoke B3 and each second magnetic pole portion B2. The second divided core 61B is fitted into the lower portion B4 and the upper portion B5. The lower portion B4 and the upper portion B5 are formed of an insulating material such as resin. The second insulator 63B electrically insulates the coil 62 wound around the second spoke B3 from the second spoke B3.

[0027] The annular portion 61a of the stator core 61 is formed by connecting the first portion A1 to the upper side of the second portion B1. The annular first portion A1 and the annular second portion B1 are formed to have substantially the same shape and dimensions. The first spoke A3 extends outward along the upper surface of the first portion A1 and protrudes from the lower surface of the first portion A1 toward the second portion B1. The axial dimensions of the first spoke A3 and the first pole portion A2 coincide with the axial dimensions of the annular portion 61a. A part of the first pole portion A2 protrudes downward from the first portion A1. On the other hand, the second spoke B3 extends outward along the lower surface of the second portion B1 and protrudes from the upper surface of the second portion B1 toward the first portion A1. The axial dimensions of the second spoke B3 and the second pole portion B2 coincide with the axial dimensions of the annular portion 61a. A part of the second pole portion B2 protrudes upward from the second portion B1.

[0028] Figure 5 is a schematic perspective view showing the structure of a stator assembly 3 according to one specific example. Figure 6 is an exploded perspective view showing the structure of a stator assembly 3 according to one specific example. Referring to Figures 5 and 6 together, the substrate 7 has an annular portion (hereinafter referred to as the "substrate body") 71 around the axis of rotation x, and a plurality of lands 72 formed on the upper surface of the substrate body 71. The substrate body 71 has an upper surface and a lower surface. The substrate body 71 is formed of, for example, an insulating material, such as a resin material. The substrate body 71 is formed in a flat plate shape along a plane perpendicular to the axis of rotation x. In this example, the substrate 7 is fixed to the upper surface of the annular portion 61a of the stator core 61 via an insulator 63 at the lower surface of the substrate body 71. The substrate 7 is fixed to the insulator 63 with, for example, an adhesive.

[0029] Figure 7 is a schematic plan view showing the structure of a stator assembly 3 according to one specific example. In this example, a plurality of (three in this example) land groups 73 are formed on the upper surface of the substrate body 71. Each land group 73 has a plurality of (eight in this example) lands 72 arranged in the circumferential direction. In this example, the three land groups 73 are arranged at predetermined intervals (equal intervals in this example) in the circumferential direction. The lands 72 have a first land 72A arranged on the inner circumference side and a second land 72B arranged on the outer circumference side. The conductors 62a of the coil 62 are connected to some of the first lands 72A and the second lands 72B by, for example, soldering or fusing (thermocompression bonding using electrical resistance).

[0030] In each land group 73, in the circumferential direction, two first lands 72A, 72A on the inner circumference and two second lands 72B, 72B on the outer circumference are arranged alternately. In this example, each first land 72A and second land 72B is positioned in the circumferential direction at a location corresponding to the side surface of the spokes 61c (first spoke A3 and second spoke B3) of the stator core 61. In one example, eight lands 72 are arranged between five spokes 61c that are aligned in the circumferential direction. The conductors 62a of the coil 62, which are wound around the spokes 61c clockwise (CW) or counterclockwise (CCW), are pulled out upwards, bent along the upper surface of the substrate body 71, and then electrically connected to the first land 72A or the second land 72B.

[0031] In the motor 2, for example, three phases (U phase, V phase, and W phase) of coils 62 are set up, and the three land groups 73 correspond to each phase. That is, the conductors 62a of the coils 62 drawn out toward each land group 73 correspond to the starting and ending windings of each phase. The stator core 61 is composed of a first divided core 61A and a second divided core 61B, and three phases of coils 62 are set up in each of the first divided core 61A and the second divided core 61B, respectively. Therefore, for each of the first divided core 61A and the second divided core 61B, a total of six conductors 62a are drawn out, consisting of the starting and ending windings of each phase of the conductors 62a of the three phases of coils 62, and four of these conductors 62a are drawn out toward each land group 73.

[0032] Figure 8 is a partially enlarged cross-sectional view along the line 8-8 in Figure 7. In this example, the substrate body 71 of the substrate 7 is positioned radially inward (on the inner circumference side) of the stator 6. The outer peripheral edge (outer circumference portion) 74 defined along the outer circumference end of the substrate body 71 is fixed to the upper surface of the insulator 63 on the upper surface of the annular portion 61a of the stator core 61. The outer peripheral edge 74 is formed in an annular shape. Adhesives or the like may be used to fix the substrate body 71 and the insulator 63. In this example, the outer peripheral edge 74 of the substrate body 71 is positioned on the inner circumference side of the inner circumference end of the coil 62. In this example, the outer peripheral edge 74 of the substrate body 71 faces the conductor 62a of the coil 62 in the radial direction. On the other hand, an inner peripheral edge 75 is defined along the inner circumference end of the substrate body 71.

[0033] In one example, three busbars 8 are arranged circumferentially to correspond to three phases (U phase, V phase, and W phase) coils 62. Each busbar 8 has a flat plate portion (hereinafter referred to as the "flat plate portion") 81 that extends in a direction intersecting (perpendicular to) the rotation axis x or along a plane, a portion (hereinafter referred to as the "extended portion") 82 that extends axially or downward from the inner circumference of the flat plate portion 81, and a bent portion (hereinafter referred to as the "curved portion") 83 that connects the flat plate portion 81 and the extended portion 82. The curved portion 83 forms part of a cylinder with the rotation axis x as its central axis. In one example, a part of the flat plate portion 81 extends from the inner circumference 75 into the substrate body 71. That is, a part of the flat plate portion 81 is held within the substrate body 71. In this example, a portion of the flat portion 81 of the busbar 8 is embedded within the substrate body 71 by insert molding the substrate 7 with a portion of the flat portion 81 of the busbar 8 placed inside the mold.

[0034] In one example, the flat plate portion 81 has terminal portions (not shown) that extend radially and circumferentially within the substrate body 71. The aforementioned lands 72 (first land 72A, second land 72B) are formed by a part of these terminal portions being exposed on the upper surface of the substrate body 71. That is, the lands 72 constitute a part of the busbar 8. Current is supplied to the coil 62 or drawn from the coil 62 via the busbar 8. The busbar 8 is integrally formed from a metallic material. The metallic material includes, for example, copper. In addition, an insulating layer (not shown) is formed on the surface of the busbar 8 other than the lands 72 by surface treatment such as an insulating coating. Alternatively, a conductive thin film (wiring) may be formed on the substrate body 71 instead of the terminal portions. In this case, the lands 72 and the busbar 8 are formed separately from each other.

[0035] In one example, the heat sink 9 has a body 91 and a plurality of fins 92. The body 91 extends in an arc shape over a predetermined range in the circumferential direction, for example, in a plan view in the axial direction. However, the body 91 may be formed in a cylindrical shape with the rotation axis x as its central axis. The plurality of fins 92 are arranged at predetermined intervals (for example, equally spaced) in the circumferential direction. In this example, each fin 92 extends radially from the inner circumferential surface of the body 91. Each fin 92 is formed in a flat plate shape extending along a plane containing the rotation axis x. The plurality of fins 92 are integrally formed on the inner circumferential surface of the body 91. The heat sink 9 is formed by extrusion molding of a metal material having high thermal conductivity, such as aluminum.

[0036] The heat sink 9 is fixed to the inner surface of the extended portion 82 of the busbar 8 from the outer surface of the main body 91. In this example, the main body 91 is fixed to the busbar 8 by press-fitting. As mentioned above, an insulating layer is formed on the surface of the busbar 8, at least excluding the land 72, so the busbar 8 is electrically insulated from the heat sink 9. Alternatively, instead of forming an insulating layer, an insulating material such as an insulating sheet may be sandwiched between the outer surface of the busbar 8 and the inner surface of the heat sink 9. In this example, the height of the heat sink 9 in the axial direction is set to about half the total height of the stator 6 in the axial direction. However, the height of the heat sink 9 in the axial direction may be set to be about the same as the total height of the stator 6 in the axial direction.

[0037] Returning to Figure 2, the substrate 7 extends further inward than the first sleeve 22 of the frame 2. Thus, the busbar 8 and heat sink 9 are positioned in the internal space formed between the inner surface of the first sleeve 22 and the outer surface of the second sleeve 23. In this example, the inner ends of the multiple fins 92 of the heat sink 9 face the outer surface of the second sleeve 23 with a predetermined gap between them. In this example, the multiple fins 92 are formed in a flat shape along a plane containing the axis of rotation x, so that air passages extending in the axial direction are formed between circumferentially adjacent fins 92, 92. These passages are connected in the axial direction to through holes 26, 27 formed in the frame 2. These passages also face the vanes 54 on the lower surface of the housing 51 in the axial direction.

[0038] In the motor 1 described above, when current is supplied to the coil 62, the rotor 5 rotates around the rotation axis x. At this time, heat is generated in the coil 62. This heat generation increases in proportion to the increase in the load of the motor 1, i.e., the amount of current. In one example, the heat is transferred from the coil 62 to the magnetic pole portion 61b, for example, via the spokes 61c of the stator core 61. The heat is then released into the atmosphere from the magnetic pole portion 61b. Furthermore, in another example, the heat is transferred from the coil 62 to the frame 2, for example, via the spokes 61c and the annular portion 61a of the stator core 61. The heat is then released into the atmosphere from the first sleeve 22 of the frame 2, the first portion 24, the second portion 25 of the base 21, etc.

[0039] Furthermore, in another example, heat is transferred from the conductor 62a of the coil 62 to the flat plate portion 81 via the lands 72 (first land 72A, second land 72B) and terminal portion. Subsequently, heat is transferred from the curved portion 83 and extended portion 82 of the busbar 8 to the body 91 of the heat sink 9. In the heat sink 9, heat is released into the atmosphere from the fins 92 via the body 91. In the motor 1, the rotation of the rotor 5, i.e., the blades 54 of the housing 51, generates an airflow that flows into the internal space, for example, through the through holes 26 and 27 of the frame 2, passes around the coil 62, and flows out into the external space. This airflow carries the heat released from the frame 2, heat sink 9, coil 62, and stator core 61, respectively. In this way, the motor 1 can efficiently release heat through multiple heat transfer routes. The coil 62 is cooled within the motor 1.

[0040] In the circumferential direction, the substrate 7 may be positioned at a specific location relative to the stator core 61, or it may be positioned at any location. For example, the position of the substrate 7 in the circumferential direction may be appropriately changed depending on the number of magnetic pole portions 61b or spokes 61c of the stator core 61, or depending on the position of the conductors 62a drawn from the coils 62. Such position changes may be appropriately set, for example, according to the specifications of the windings of the coils 62 of the stator core 61 (clockwise (CW) winding, counterclockwise (CCW) winding, number of turns, etc.). Furthermore, the position change may be made by moving the substrate 7 in the circumferential direction by, for example, the width of one spoke 61c (one slot).

[0041] Although the present invention has been described above through the embodiments described above, the technical scope of the present invention is not limited to the scope described in the embodiments above. It will be obvious to those skilled in the art that various modifications or improvements can be made to the embodiments described above. It will be clear from the claims that such modified or improved forms may also be included in the technical scope of the present invention.

[0042] The embodiments described above are for the purpose of facilitating understanding of the present invention and are not intended to limit its interpretation. Furthermore, the embodiments described above do not limit the scope of application of the present invention, and the present invention may encompass anything as its target application. The components of the above embodiments, as well as their arrangement, materials, conditions, shapes, sizes, etc., are not limited to those exemplified and can be modified as appropriate.

[0043] For example, the present invention includes differences that arise in the implementation of manufacturing tolerances, etc. Furthermore, components shown in different embodiments can be partially substituted or combined to the extent that they do not conflict with the technical requirements. In addition, each component can be selectively combined as appropriate to achieve at least some of the above-mentioned problems and effects.

[0044] 1 Motor, 11 Bearing, 12 Wiring, 2 Frame, 21 Base, 22 First Sleeve, 23 Second Sleeve, 23a Protrusion, 24 First Part, 25 Second Part, 26 Through Hole, 27 Through Hole, 28 Screw Hole, 29 Pusher, 3 Stator Assembly, 4 Shaft, 5 Rotor, 51 Housing, 52 Yoke, 53 Magnet, 54 Blades, 6 Stator, 61 Stator Core (Magnetic Material), 61a Annular Part, 61b Magnetic Pole Part, 61c Spoke, 61A First Split Core, 61B Second Split Core, A1 First Part, A2 First Magnetic Pole Part, A3 First Spoke, A4 Upper Part, A5 Lower Part, B1 Second Part, B2 Second Magnetic Pole Part, B3 Second Spoke, B4 Lower Part, B5 Upper Part, 62 Coil, 62a Conductor, 63 Insulator, 7 Circuit board, 71 Ring portion (main body of the circuit board), 72 Land, 72A First land, 72B Second land, 73 Land group, 74 Outer edge (outer part), 75 Inner edge, 8 Busbar, 81 Flat portion (flat part), 82 Extending portion (extending part), 83 Bent portion (curved part), 9 Heat sink, 91 Main body, 92 Fin, x Rotation axis

Claims

1. A motor comprising: a stator having a plurality of coils; a busbar disposed on the inner circumference side of the stator and to which the coils are connected; and a heat sink disposed on the inner circumference side of the busbar and in contact with the busbar, wherein the busbar is electrically insulated from the heat sink.

2. The motor according to claim 1, wherein the busbar is held on a substrate attached to the inner circumference of the stator.

3. The motor according to claim 2, wherein the busbar forms two electrically connectable lands on the substrate, arranged on both sides of the coil in the circumferential direction.

4. The motor according to claim 2, wherein the busbar is formed on the substrate and connected to two electrically connectable lands located on both sides of the coil in the circumferential direction.

5. The motor according to claim 3 or 4, wherein the two lands comprise a first land and a second land, the first land being on the inner circumference in the radial direction and the second land being on the outer circumference in the radial direction.

6. The motor according to any one of claims 1 to 5, wherein the stator comprises a plurality of segmented cores that can be divided in the axial direction.

7. The motor according to any one of claims 1 to 6, wherein the outer periphery of the substrate is annular.

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