Motor and unmanned vehicle

Abstract

A motor (2) comprises: a stator (6) having a first split core (8A) and a second split core (8B) that can be split in the axial direction, a first coil (9A) wound around the first split core (8A), and a second coil (9B) wound around the second split core (8B); and a substrate (7) disposed on the radially inner side of the stator (6). The substrate (7) comprises: first lands (72) which are electrically connected to the first coil (9A); second lands (72) which are electrically connected to the second coil (9B); and wiring (75). The first lands (72) and the second lands (72) are arranged in the circumferential direction.

Description

Motor and Unmanned Aerial Vehicle

[0001] The present invention relates to a motor and an unmanned aerial vehicle.

[0002] For example, Patent Document 1 discloses a stator assembly in which a holder is arranged on the inner circumferential side of a stator core. In this stator assembly, the conductive wires of coils wound around each tooth of the stator core are drawn out to the holder and held by the holder.

[0003] Japanese Patent Laid-Open No. 9-56103

[0004] To achieve higher output of a motor, it is required to increase the number of teeth and improve the winding density (occupancy) of coils. As a solution to such a problem, for example, a configuration in which a stator core can be divided into two split cores in the axial direction has been proposed. However, as the number of teeth increases, the number of lead wires of coils increases, which complicates wiring work.

[0005] The present invention has been made in view of the above problems, and an example of an object of the present invention is to provide a motor and an unmanned aerial vehicle capable of simplifying wiring work.

[0006] A motor according to one aspect of the present invention comprises: a stator including a first split core and a second split core that are splittable in an axial direction, a first coil wound around the first split core, and a second coil wound around the second split core; and a substrate located radially inside the stator, wherein the substrate includes a first land electrically connected to the first coil, a second land electrically connected to the second coil, and a wiring, and the first land and the second land are arranged side by side in a circumferential direction.

[0007] An unmanned aerial vehicle according to one aspect of the present invention includes the motor described above, and the motor includes a plurality of blades provided on a rotor.

[0008] This is a schematic perspective view showing a part of the structure of an unmanned aircraft 1 according to one embodiment of the present invention. This is a cross-sectional view along line 2-2 in Figure 1. This is a partially exploded perspective view of a motor 2 according to one embodiment of the present invention. This is a schematic perspective view showing the structure of a stator assembly 3 according to one specific example. This is a cross-sectional view along line 5-5 in Figure 4. This is a schematic exploded perspective view showing the structure of a stator assembly 3 according to one specific example. This is a schematic exploded perspective view showing the structure of a stator core 8 according to one specific example. This is a schematic exploded perspective view showing the structure of a first divided core 8A according to one specific example. This is a schematic exploded perspective view showing the structure of a second divided core 8B according to one specific example. This is a partially enlarged plan view of a stator assembly 3 showing the structure of a substrate 7 according to one specific example. This is an exploded perspective view of a stator assembly 3 to explain the scene of manufacturing the stator assembly 3.

[0009] 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 an unmanned aircraft 1 according to one embodiment of the present invention. In one example, the unmanned aircraft 1 is a so-called multicopter equipped with a propulsion device 11 attached to the tip of an arm (not shown) extending from the main body of the unmanned aircraft 1. In the following description, the terms "up" and "down" will be used for convenience, but 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 viewed in relation to the propulsion device 11 alone.

[0010] The propulsion system 11 comprises a motor 2 and a propeller 12. The motor 2 supports the propeller 12 so that it can rotate around a rotation axis x. The propeller 12 is fixed to the rotor of the motor 2, which will be described later, using, for example, a fixing member such as a screw. In one example, the propeller 12 consists of two blades 13, 13 that extend in opposite directions to each other in a direction perpendicular to the rotation axis x. The two blades 13, 13 have the same shape as each other. By rotating the propeller 12 around the rotation axis x, the propulsion system 11 can generate lift and thrust for the unmanned aircraft 1.

[0011] The main body of the unmanned aircraft 1 incorporates components such as a control device for controlling the aircraft's drive, a battery, various sensors, and a camera. Multiple arms extend radially from this main body, for example. Power is supplied to the motors 2 from the battery, etc., via wiring housed in the internal space of the arms. Each propulsion device 11 is attached, for example, to the tip of each arm. The tips of the arms may also be provided with attachments (not shown) to support the motors 2. The attachments may be integrally formed with the arms, for example, or they may be formed separately from the arms.

[0012] Figure 2 is a cross-sectional view along line 2-2 in Figure 1. Figure 3 is an exploded perspective view of a motor 2 according to one embodiment of the present invention. Note that the propeller 12 is not shown in Figure 3. Referring to Figures 2 and 3 together, the motor 2 comprises a frame 5, a stator assembly 3 fixed to the frame 5, a shaft 16 rotatably supported by the frame 5 via, for example, two bearings 14, and a rotor 4 fixed to the shaft 16. Note that the shaft 16 is a cylindrical portion 44, which will be described later. The stator assembly 3 has a stator 6 and a substrate 7. The frame 5 as a whole is formed in an annular shape around the axis of rotation x. The frame 5 has a base 51, a first wall 52, and a second wall (sleeve) 53, all formed in an annular shape around the axis of rotation x.

[0013] The base 51 has a first portion 54 extending along a plane perpendicular to the axis of rotation x, and a second portion 55 that inclines toward the outer circumference in the radial direction perpendicular to the axis of rotation x from the first portion 54 toward one side, i.e., the upper side, in the direction along the axis of rotation x (hereinafter referred to as "axial direction"). The first portion 54 has one or more (eight in this example) through holes 56 that penetrate the first portion 54 in the axial direction. The second portion 55 also has one or more (eight in this example) through holes 57 that penetrate the second portion 55 in the axial direction. These through holes 56 and 57 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.

[0014] The first wall 52 is a wall integrally formed on the outer circumferential end of the second portion 55 of the base 51. The first wall 52 is formed in a cylindrical shape with respect to the axis of rotation x. The stator assembly 3 is fixed to the outer circumferential surface of the first wall 52. The second wall 53 is a wall integrally formed on the inner circumferential end of the first portion 54 of the base 51. The second wall 53 is formed in a cylindrical shape with respect to the axis of rotation x. The outer rings of two bearings 14 are held on the inner circumferential surface of the second wall 53. The outer rings of the bearings 14 are fitted onto the inner circumferential surface of the second wall 53 and fixed, for example, with adhesive. The shaft 16 is supported on the inner ring of the bearing 14.

[0015] An annular internal space is formed between the inner surface of the first wall 52 and the outer surface of the second wall 53, around the axis of rotation x. Through holes 56 and 57 in the base 51 are connected to this internal space. Therefore, this internal space is connected to the external space of the motor 2. A flat cylindrical pusher 58, for example, is attached to the lower end of the second wall 53. In this example, the pusher 58 applies a predetermined preload to the outer ring of the lower bearing 14 in the axial direction. The motor 2 is fixed to the aforementioned attachment via fixing members such as screws, for example, on the base 51. The frame 5 is integrally formed from, for example, a metal material or a resin material.

[0016] A stator assembly 3 is fixed to the outer circumferential surface of the first wall 52. The stator assembly 3 is formed in an annular shape around the axis of rotation x. In one example, the stator 6 of the stator assembly 3 has a stator core (magnetic material) 8, a plurality of coils 9, and an insulator 10. The stator core 8 is formed from a laminate of a plurality of sheets of, for example, electromagnetic steel sheets (magnetic material), and functions as a yoke for the stator assembly 3. The coils 9 are wound around each spoke of the stator core 8, which will be described later. The insulator 10 is placed between the stator core 8 and the coils 9. In this way, electrical insulation is established between the stator core 8 and the coils 9. The substrate 7 is formed in an annular shape, for example. The substrate 7 is provided on the insulator 10 that covers the stator core 8.

[0017] On the other hand, the rotor 4 includes a housing 41, a yoke 42, and a magnet 43. The housing 41 has a cylindrical portion (hereinafter referred to as the "tube portion") 44 centered on the axis of rotation x, a cover 45 extending radially outward from the tube portion 44, and one or more blades 46 formed on the inner surface (bottom surface) of the cover 45. The outer surface of the tube portion 44 is fixed to the inner ring of the bearing 14. The propeller 12 is fixed to the upper end of the tube portion 44 via a fixing member (not shown), such as a screw. In this way, the propeller 12 rotates together with the tube portion 44, i.e., the shaft 16, around the axis of rotation x. In this embodiment, the tube portion 44, which serves as the shaft 16, is formed as part of the rotor 4.

[0018] As shown in Figure 3, the cover 45 is formed of a disc-shaped plate material that slopes downward towards the outer circumference. The cover 45 has no through holes or openings and has a continuous surface that covers the opening of the housing 41. Multiple radially extending blades 46 are formed on the inner surface of the cover 45. In this example, eight blades 46 are arranged at predetermined intervals (e.g., equal intervals) in the circumferential direction. Each blade 46 is, for example, a plate material, spoke, or rod that extends along a plane containing the rotation axis x. In this example, the lower end of each blade 46 is defined along a plane perpendicular to the rotation axis x. These blades 46 can generate airflow by causing air to flow in the internal space of the motor 2 when the rotor 4 rotates around the rotation axis x.

[0019] A generally cylindrical yoke 42 is formed at the outer peripheral end of the cover 45. A cylindrical magnet 43 is attached to the inner circumferential surface of the yoke 42. The yoke 42 is made of, for example, a magnetic material. The magnet 43 is, for example, a permanent magnet. In this example, the magnet 43 is made of two cylindrical permanent magnets stacked in the axial direction. The inner circumferential surface of the magnet 43 faces the stator core 8. The inner circumferential surface of the magnet 43 and the outer circumferential surface of the stator core 8 face each other with a predetermined space between them. This space forms a predetermined magnetic gap in the radial direction.

[0020] Multiple wires 15 are held on the underside of the base 51 of the frame 5. These wires 15 pass through, for example, through holes 56 in the base 51 and are electrically connected to multiple coils 9 via the substrate 7 of the stator 6. In this way, current is supplied to the coils 9 from the battery of the main body of the unmanned aircraft 1. When current is supplied to the coils 9, a magnetic interaction is generated between the coils 9 and the magnet 43. This magnetic interaction allows the rotor 4 to rotate around the rotation axis x. The rotor 4 surrounds the stator 6. This motor 2 is a so-called outer rotor type motor.

[0021] Figure 4 is a schematic perspective view showing the structure of a stator assembly 3 according to one specific example. Figure 5 is a cross-sectional view along line 5-5 in Figure 4. Referring to Figures 4 and 5 together, the stator core 8 of the stator 6 has an annular portion 81 formed in an annular shape with respect to the rotation axis x, a plurality of (24 in this example) magnetic pole portions 82 arranged in the circumferential direction around the rotation axis x, and spokes 83 connecting the annular portion 81 and the magnetic pole portions 82 to each other. Each spoke 83 protrudes radially outward from the outer circumferential surface of the annular portion 81. The magnetic pole portions 82 are integrally formed at the outer circumferential ends of the spokes 83. The magnetic pole portions 82 extend in the circumferential direction.

[0022] The magnetic pole portion 82 and the spoke 83 form what is known as teeth. The conductor 9a forming the coil 9 is wound around each spoke 83 in a clockwise or counterclockwise direction around a winding axis defined in the radial direction. An insulator 10 is placed between the spoke 83 and the coil 9. The insulator 10 is made of an insulating material, such as a resin material. The insulator 10 may be integrally formed with the stator core 8 by insert molding, for example. In this way, the spoke 83, i.e., the stator core 8, and the conductor 9a of the coil 9 are electrically insulated from each other.

[0023] As shown in Figure 4, 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 body 71 is positioned radially inward (on the inner circumference side) of the stator 6. An outer peripheral edge 73 defined along the outer peripheral end of the substrate body 71 is provided on and fixed to the upper surface of the insulator 10 on the upper surface of the annular portion 81 of the stator core 8. Adhesives or the like may be used to fix the substrate body 71 and the insulator 10. In this example, the outer peripheral end (outer peripheral edge 73) of the substrate body 71 is positioned on the inner circumference side of the inner peripheral end of the coil 9.

[0024] In this example, multiple (three in this example) land groups 74 are formed on the upper surface of the substrate body 71. Each land group 74 has multiple (eight in this example) lands 72 arranged in the circumferential direction. In this example, the three land groups 74 are arranged at predetermined intervals (equal intervals in this example) in the circumferential direction. The lands 72 are conductive patterns formed on the upper surface of the substrate body 71, for example, by copper foil. The lands 72 have lands 72A arranged on the inner circumference side and lands 72B arranged on the outer circumference side. The conductors 9a of the coil 9 are connected to some of the lands 72A and 72B by means of soldering or fusing (thermocompression bonding using electrical resistance).

[0025] Figure 6 is an exploded perspective view schematicly showing the structure of a stator assembly 3 according to one specific example. In this stator assembly 3, the stator core 8 has a first divided core 8A and a second divided core 8B that can be divided in the axial direction. In this example, the first divided core 8A is positioned above the second divided core 8B in the axial direction. The first divided core 8A has an annular first portion 81A, a plurality of first pole portions 82A, and a plurality of first spokes 83A that connect the first portion 81A and the plurality of first pole portions 82A. Similarly, the second divided core 8B has an annular second portion 81B, a plurality of second pole portions 82B, and a plurality of second spokes 83B that connect the second portion 81B and the plurality of second pole portions 82B.

[0026] In the first segmented core 8A, twelve first spokes 83A extend outward from the first section 81A. The twelve first spokes 83A are arranged at equal intervals in the circumferential direction. A portion of the first segmented core 8A is covered by the first insulator 10A. A first coil 9A is wound around each first spoke 83A. Meanwhile, twelve second spokes 83B extend outward from the second section 81B. The twelve second spokes 83B are arranged at equal intervals in the circumferential direction. A portion of the second segmented core 8B is covered by the second insulator 10B. A second coil 9B is wound around each second spoke 83B.

[0027] The annular portion 81 is formed by connecting the first portion 81A to the upper side of the second portion 81B. The annular first portion 81A and the annular second portion 81B are formed to have substantially the same shape and dimensions as each other. The first spoke 83A extends outward along the upper surface of the first portion 81A. The axial dimensions of the first spoke 83A and the first pole portion 82A coincide with the axial dimensions of the annular portion 81. A portion of the first pole portion 82A protrudes downward from the first portion 81A. On the other hand, the second spoke 83B extends outward along the lower surface of the second portion 81B. The axial dimensions of the second spoke 83B and the second pole portion 82B coincide with the axial dimensions of the annular portion 81. A portion of the second pole portion 82B protrudes upward from the second portion 81B.

[0028] Figure 7 is an exploded perspective view schematically showing the structure of a stator core 8 according to one specific example. Referring together to Figures 5 and 7, projections 84 are formed on the inner circumference ends of three of the twelve second spokes 83B of the second divided core 8B, projecting inward. In this example, the projections 84 are formed on the entire length of the second spoke 83B from the upper surface of the second portion 81B. The second spokes 83B on which the projections 84 are formed are arranged at equal intervals in the circumferential direction. On the other hand, three recesses 85 are formed on the outer circumference of the first portion 81A of the first divided core 8A, corresponding to the projections 84 and recessing inward from the outer circumference. When the first portion 81A and the second portion 81B are connected in the axial direction, the three projections 84 fit into the three recesses 85, respectively.

[0029] When the first divided core 8A and the second divided core 8B are connected in the axial direction, the first spoke 83A, the first magnetic pole portion 82A and the first coil 9A, and the second spoke 83B, the second magnetic pole portion 82B and the second coil 9B are arranged alternately in the circumferential direction, as shown in Figures 4 to 6 above. The axial dimensions of the first spoke 83A and the first magnetic pole portion 82A, the axial dimensions of the second spoke 83B and the second magnetic pole portion 82B, and the dimensions of the annular portion 81 in the axial direction all coincide, and the first spoke 83A and the first magnetic pole portion 82A and the second spoke 83B and the second magnetic pole portion 82B overlap in the axial direction and are positioned at the same location in the radial and circumferential directions.

[0030] Figure 8 is an exploded perspective view schematically showing the structure of a first divided core 8A according to one specific example. Note that the coil 9A is not shown in Figure 8. The first insulator 10A has an upper portion 101 that covers the first portion 81A, the first spoke 83A, and the first magnetic pole portion 82A from above, and a lower portion 102 that covers the first spoke 83A and the first magnetic pole portion 82A from below, respectively. Both the upper portion 101 and the lower portion 102 are, for example, resin films integrally formed on the first divided core 8A by insert molding of a resin material while the first divided core 8A is placed in a mold.

[0031] The upper portion 101 has an inner circumferential portion 101a that covers the upper surface and outer circumferential surface of the first portion 81A, and an outer circumferential portion 101b that covers the upper surface and (both) sides (when viewed from the circumferential direction) of the first spoke 83A and the upper surface and (two) back surfaces (when viewed from the radial direction) of the first magnetic pole portion 82A. When the first insulator 10A is attached to the first divided core 8A, the outer circumferential edge 73 of the substrate body 71 of the substrate 7 is fixed on the inner circumferential portion 101a of the first insulator 10A. In addition, around the rotation axis x, a plurality of recesses (hereinafter referred to as "notches") 103 are formed in the inner circumferential portion 101a that are recessed upward from the lower end of the inner circumferential portion 101a. The notches 103 are configured to accommodate the second spoke 83B of the second divided core 8B when the first divided core 8A and the second divided core 8B are connected.

[0032] Each lower portion 102 partially covers the portion of the first spoke 83A and the first magnetic pole portion 82A below the lower surface of the first portion 81A. Specifically, the lower portion 102 covers the lower surface and sides of the first spoke 83A and the lower surface and back of the first magnetic pole portion 82A. In this way, the entire upper, lower, and side surfaces of the first spoke 83A and the entire upper, lower, and back surfaces of the first magnetic pole portion 82A are covered by the outer circumference 101b of the upper portion 101 and the lower portion 102. In this way, the first insulator 10A electrically insulates the first coil 9A wound around the first spoke 83A from the first spoke 83A.

[0033] Figure 9 is an exploded perspective view schematically showing the structure of the second divided core 8B according to one specific example. Note that the coil 9B is not shown in Figure 9. The structure of the second insulator 10B is symmetrical with respect to the structure of the first insulator 10A with respect to a plane perpendicular to the rotation axis x. Specifically, the second insulator 10B has a lower portion 104 corresponding to the upper portion 101 and an upper portion 105 corresponding to the lower portion 102. The lower portion 104 has an inner circumference portion 104a and an outer circumference portion 104b, which correspond to the inner circumference portion 101a and outer circumference portion 101b, respectively.

[0034] Furthermore, around the axis of rotation x, a plurality of recesses (hereinafter referred to as "notches") 106 are formed in the inner circumference portion 104a, extending downward from the upper end of the inner circumference portion 104a. The notches 106 are configured to accommodate the first spoke 83A of the first divided core 8A when the first divided core 8A and the second divided core 8B are connected. Note that the inner end of the inner circumference portion 101a of the upper portion 101 extends further inward than the inner end of the inner circumference portion 104a of the lower portion 104. That is, the inner circumference portion 104a of the lower portion 104 partially covers a part of the lower surface of the second portion 81B of the second divided core 8B.

[0035] As shown in Figures 5 to 9, a recess 81C is formed on the inner circumferential surface of the first portion 81A of the first divided core 8A. On the other hand, a recess 81D is formed on the inner circumferential surface of the second portion 81B of the second divided core 8B. When connecting the first divided core 8A and the second divided core 8B in the axial direction, the recess 81C and the recess 81D are aligned in the circumferential direction, thereby allowing the first divided core 8A and the second divided core 8B to be aligned with each other. The stator assembly 3, including the first divided core 8A and the second divided core 8B which are thus connected to each other, is fixed to the outer circumferential surface of the first wall 52 of the frame 5 with, for example, an adhesive. Specifically, the inner circumferential surfaces of the annular portions 81 formed by the first divided core 8A and the second divided core 8B which are connected to each other are fixed to the outer circumferential surface of the first wall 52 with an adhesive.

[0036] Figure 10 is a partially enlarged plan view of a stator assembly 3 that schematically shows the structure of a substrate 7 according to one specific example. In Figure 10, a region including one land group 74 is shown. In each land group 74, two lands 72B, 72B on the inner circumference and two lands 72A, 72A on the outer circumference are arranged alternately in the circumferential direction. In this example, each land 72A, 72B is positioned in the circumferential direction at a position corresponding to the side surface of the first spoke 83A and the second spoke 83B. In this example, eight lands 72 are arranged between five first spokes 83A and second spokes 83B that are aligned in the circumferential direction.

[0037] Specifically, lands 72A and 72B are positioned corresponding to the three central first spokes 83A and second spokes 83B, and to the positions on both sides of the first spokes 83A and second spokes 83B. Furthermore, two adjacent lands 72A in the circumferential direction are located between adjacent first spokes 83A and second spokes 83B in the circumferential direction. Similarly, two adjacent lands 72B in the circumferential direction are located between adjacent second spokes 83B and first spokes 83A in the circumferential direction. In addition, one land 72A and one land 72B are positioned corresponding to each of the first spokes 83A, second spokes 83B, and first spokes 83A. With this arrangement of lands 72A and 72B, for example, in the three central first spokes 83A, second spokes 83B and first spoke 83A, the coil 9 can be wound around these first spokes 83A, second spokes 83B and first spoke 83A in either a clockwise (CW) or counterclockwise (CCW) direction.

[0038] In this example, the wire 9a of the leftmost second coil 9B in Figure 10 is wound counterclockwise (CCW) around the second spoke 83B. After being wound around the second spoke 83B, this wire 9a is pulled out upwards, bent along the upper surface of the substrate body 71, and then electrically connected to the inner-circumferential land (second land) 72B of the substrate 71. Similarly, the wire 9a of the second first coil 9A from the left is wound clockwise (CW) around the first spoke 83A. After being wound around the first spoke 83A, this wire 9a is pulled out upwards, bent along the upper surface of the substrate body 71, and then electrically connected to the inner-circumferential land (first land) 72B of the substrate 7.

[0039] Furthermore, the wire 9a of the rightmost second coil 9B is wound clockwise (CW) around the second spoke 83B. After being wound around the second spoke 83B, this wire 9a is pulled out upwards, bent along the top surface of the main board body 71, and then electrically connected to the outer peripheral land (second land) 72B of the main board 7. Also, the wire 9a of the second first coil 9A from the right is wound clockwise (CW) around the first spoke 83A. After being wound around the first spoke 83A, this wire 9a is pulled out upwards, bent along the top surface of the main board body 71, and then electrically connected to the inner peripheral land (first land) 72B of the main board 7.

[0040] In the motor 2, for example, three-phase (U-phase, V-phase, and W-phase) coils 9 are configured, and the three land groups 74 correspond to each phase. That is, the conductors 9a of coils 9A and 9B drawn out toward each land group 74 correspond to the starting and ending windings of each phase. The stator core 8 is composed of a first divided core 8A and a second divided core 8B, and three-phase coils 9A and 9B are configured in each divided core 8A and 8B, respectively. Therefore, a total of four conductors 9a are drawn out toward each land group 74, consisting of the starting and ending windings of each phase of the conductors 9A and 9B.

[0041] Furthermore, as shown in Figure 10, on the substrate 7, wiring 75 extends from each land 72A, 72B. The wiring 75 may be formed along the upper surface of the substrate body 71, or it may be formed inside the substrate body 71. Current is supplied to each land 72A, 72B of the U-phase, V-phase, and W-phase via these wirings 75, while current is drawn from each land 72A, 72B of the U-phase, V-phase, and W-phase. Since the lands 72A, 72B are arranged on both the outer and inner circumference sides of the substrate body 71, it is easy to secure a routing area for the wiring 75 on the substrate body 71.

[0042] Figure 11 is an exploded perspective view of the stator assembly 3 to illustrate the manufacturing process. Prior to the manufacturing of the stator assembly 3, the first insulator 10A and the second insulator 10B are formed on the first split core 8A and the second split core 8B, respectively, by, for example, insert molding. In addition, the first coil 9A and the second coil 9B are wound around the first spoke 83A and the second spoke 83B of the first split core 8A and the second split core 8B, respectively. The conductors 9a of the first coil 9A or the second coil 9B, which constitute the winding start and end lines for each of the three phases, are drawn out.

[0043] In the first divided core 8A, the outer edge 73 of the substrate 7 is pre-fixed to the inner circumference 101a of the upper portion 101 of the first insulator 10A. Also, the wires 9a of the first coil 9A, which is wound around the first spoke 83A of the first divided core 8A, are pre-electrically connected to the lands 72A and 72B on the substrate body 71 of the substrate 7. In this state, the second divided core 8B is connected to the first divided core 8A. With the recess 81C on the inner circumference surface of the first portion 81A of the first divided core 8A and the recess 81D on the inner circumference surface of the first portion 81B of the second divided core 8B aligned in the circumferential direction, the annular first portion 81A of the first divided core 8A is placed on the annular second portion 81B of the second divided core 8B. At this time, as shown in Figure 5, the inner circumference projection 84 of the second spoke 83B fits into the recess 85 on the outer circumference surface of the first portion 81A. In this way, the first divided core 8A is positioned in a predetermined position relative to the second divided core 8B.

[0044] At the same time, the second spokes 83B and the first spokes 83A are inserted into the notch 103 of the first insulator 10A and the notch 106 of the second insulator 10B, respectively. As described above, in the upper first divided core 8A, the six conductive wires 9a are already electrically connected to the lands 72A and 72B. Therefore, after the first divided core 8A and the second divided core 8B are connected, the six conductive wires 9a of the lower second divided core 8B are electrically connected to the lands 72A and 72B of the substrate 7. For electrical connection, after the conductive wire 9a having an extra portion is cut to a length corresponding to the lands 72A and 72B in advance, the conductive wire 9a is connected to the lands 72A and 72B respectively. The stator assembly 3 is thus manufactured.

[0045] In the drone 1 described above, when current is supplied to the coil 9, the rotor 4, that is, the propeller 12, rotates about the rotation axis x. At this time, heat is generated in the coil 9, the lands 72A and 72B of the substrate 7, and the wiring 75. In addition to being directly dissipated from the coil 9 and other components, the heat is transmitted from the stator core 8 to the frame 5. The rotation of the rotor 4, that is, the blades 46 of the housing 41, generates an airflow that flows in from the external space of the motor 2 to the internal space, passes around the coil 9, and flows out to the external space of the motor 2, for example. Such airflow carries heat away from the coil 9, the substrate 7, and the frame 5. Thus, inside the motor 2, the coil 9 and the substrate 7 are cooled by the generated airflow.

[0046] Furthermore, the first coil 9A and the second coil 9B respectively wound around the axially dividable first divided core 8A and second divided core 8B are each electrically connected to the lands 72A and 72B on the substrate 7 arranged on the inner peripheral side of the stator core 8. Since the lands 72A and 72B are arranged in the circumferential direction, the wiring work of connecting the first coil 9A and the second coil 9B to the lands 72A and 72B can be simplified. Moreover, since the lands 72A and 72B are arranged at positions along the side surfaces of the first spoke 83A and the second spoke 83B in the circumferential direction, they can accommodate any coil 9 wound clockwise or counterclockwise.

[0047] Furthermore, in this example, a total of 12 conductive wires 9a including the winding start wires and winding end wires of three phases are led out from the coil 9. Since a total of 4 winding start wires and winding end wires of each of the three phases are aggregated into one land group 74, the wiring work can be organized. In addition, when manufacturing the stator assembly 3, the wiring work of the 6 conductive wires 9a in the upper first divided core 8A and the wiring work of the 6 conductive wires 9a in the lower second divided core 8B can be performed separately. Therefore, the wiring work can be simplified compared to the case where the wiring work for 12 conductive wires is performed all at once. In addition, since extra lands 72A and 72B are formed, the substrate 7 can comply with various specifications.

[0048] It should be noted that, in the circumferential direction, the substrate 7 may be arranged at a specific position relative to the stator core 8, or may be arranged at any arbitrary position. For example, the position of the substrate 7 in the circumferential direction may be appropriately changed according to the number of the plurality of magnetic pole portions 82 or the number of spokes 83 included in the stator core 8, or according to the positions of the conductive wires 9a led out from the plurality of coils 9. Such a position change may be appropriately set, for example, according to the winding specifications of the coil 9 on the stator core 8 (clockwise (CW) winding, counterclockwise (CCW) winding, number of turns, etc.). In addition, the position may be changed by moving the substrate 7 in the circumferential direction by an amount corresponding to one spoke 83 (one slot), for example.

[0049] The present invention has been described above through the above embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that the forms with such changes or improvements can also be included in the technical scope of the present invention.

[0050] 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.

[0051] 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.

[0052] 1 Unmanned aircraft, 2 Motor, 3 Stator assembly, 4 Rotor, 41 Housing, 42 Yoke, 43 Magnet, 44 Cylindrical part (tube section), 45 Cover, 46 Blades, 5 Frame, 51 Base, 52 First wall, 53 Second wall, 54 First part, 55 Second part, 56 Through hole, 57 Through hole, 58 Pusher, 6 Stator, 7 Substrate, 71 Substrate body, 72, 72A, 72B Lands, 73 Outer edge, 74 Land group, 75 Wiring, 8 Stator core, 81 Annular part, 82 Magnetic pole part, 83 Spoke, 8A First split core, 81A First annular part, 82A First magnetic pole part, 83A First spoke, 81B Second annular part, 82B Second magnetic pole part, 83B Second spoke, 8B Second split core, 81C Recess, 81D Recess, 84 Protrusion, 85 Recess, 9 Coil, 9a Wire, 10 Insulator, 10A First insulator, 10B Second insulator, 101 Upper part, 101a Inner circumference, 101b Outer circumference, 102 Lower part, 103 Notch, 104 Lower part, 105 Upper part, 104a Inner circumference, 104b Outer circumference, 106 Notch, 11 Propulsion device, 12 Propeller, 13 Blade, 14 Bearing, 15 Wiring, x Rotation axis

Claims

1. A motor comprising: a stator having a first divided core and a second divided core that are axially separable, a first coil wound around the first divided core, and a second coil wound around the second divided core; and a substrate located radially inside the stator, wherein the substrate comprises a first land electrically connected to the first coil, a second land electrically connected to the second coil, and wiring, and the first land and the second land are aligned in the circumferential direction.

2. The motor according to claim 1, wherein the first divided core comprises an annular first portion, a plurality of first magnetic pole portions, and a plurality of first spokes connecting the annular first portion and the plurality of first magnetic pole portions.

3. The motor according to claim 1 or 2, wherein the second divided core comprises an annular second portion, a plurality of second magnetic pole portions, and a plurality of second spokes connecting the annular second portion and the plurality of second magnetic pole portions.

4. The motor according to claim 1, wherein in the circumferential direction, the first land and the second land are arranged between the first spoke and the second spoke.

5. The motor according to any one of claims 1 to 4, wherein the stator comprises a first insulator covering the first divided core, and the outer edge of the substrate is fixed to the inner circumference of the first insulator.

6. The motor according to any one of claims 1 to 5, wherein the stator comprises a second insulator covering the second divided core.

7. The motor according to any one of claims 1 to 6, comprising a rotor surrounding the stator.

8. An unmanned aircraft comprising a motor according to any one of claims 1 to 7, wherein the motor comprises a plurality of blades provided on a rotor.

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