Motors and motor drive systems for drones

Abstract

This helps prevent drone crashes caused by motor failure. [Solution] The motor for the drone comprises a rotating shaft, a first motor, and a second motor. The rotating shaft extends in the axial direction. The first motor has a first rotor and a first stator. The first rotor is configured to rotate the rotating shaft. The second motor has a second rotor and a second stator. The second rotor is configured to rotate the rotating shaft.

Description

Technical Field

[0001] The present invention relates to a motor for a drone and a motor drive system.

Background Art

[0002] Generally, a drone has a main body, a plurality of arms extending radially from the main body, and motors attached to the tips of the respective arms (for example, Patent Document 1). The motor rotates a propeller. An inverter drives the motor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a risk that the motor may malfunction and the drone may crash due to damage or short circuit of the winding constituting the stator of the motor. Therefore, an object of the present invention is to suppress the crash of the drone due to a motor failure.

Means for Solving the Problems

[0005] The drone motor according to the first aspect includes a rotating shaft, a first motor, and a second motor. The rotating shaft extends in the axial direction. The first motor has a first rotor and a first stator. The first rotor is configured to rotate the rotating shaft. The second motor has a second rotor and a second stator. The second rotor is configured to rotate the rotating shaft.

[0006] This drone motor has two motors, a first motor and a second motor. Therefore, even if one motor fails, the other motor can continue to propel the drone, thus reducing the risk of crashes.

[0007] The drone motor according to the second embodiment is configured as follows in the drone motor according to the first embodiment: The first rotor has a first rotor frame, a first yoke, and a plurality of first magnets. The first yoke is cylindrical. The first yoke is attached to the first rotor frame. Each first magnet is attached to the inner circumferential surface of the first yoke. Each first magnet is positioned radially outward with respect to the first stator. The second rotor has a second rotor frame, a second yoke, and a plurality of second magnets. The second yoke is cylindrical. The second yoke is attached to the second rotor frame. Each second magnet is attached to the inner circumferential surface of the second yoke. Each second magnet is positioned radially outward with respect to the second stator.

[0008] The drone motor according to the third embodiment is configured as follows in the drone motor according to the second embodiment: The first rotor frame has a top plate portion. The second rotor frame has a bottom plate portion. The top plate portion has a plurality of first openings and at least one first arm positioned between each first opening. The first arm has a first inclined surface and a second inclined surface. The first inclined surface faces the first axial side in the first rotation direction. The second inclined surface faces the second axial side in the second rotation direction. The bottom plate portion has a plurality of second openings and at least one second arm positioned between each second opening. The second arm has a third inclined surface and a fourth inclined surface. The third inclined surface faces the first axial side in the first rotation direction. The fourth inclined surface faces the second axial side in the second rotation direction.

[0009] A drone motor according to the fourth embodiment further comprises a stator frame in addition to the drone motor according to any of the first to third embodiments. The stator frame supports a first stator and a second stator. The first rotor has a first cylindrical portion. The first cylindrical portion is positioned radially outward relative to the first stator. The second rotor has a second cylindrical portion. The second cylindrical portion is positioned radially outward relative to the second stator. The stator frame has a third cylindrical portion. The third cylindrical portion is positioned axially between the first cylindrical portion and the second cylindrical portion.

[0010] The drone motor according to the fifth embodiment is configured as follows in the drone motor according to the fourth embodiment: The first, second, and third cylindrical portions each have a first end and a second end. The first end is located on the first side in the axial direction. The second end is located on the second side in the axial direction. The first end of the third cylindrical portion overlaps with the second end of the first cylindrical portion in a radial view. The second end of the third cylindrical portion overlaps with the first end of the second cylindrical portion in a radial view.

[0011] The drone motor according to the sixth embodiment is configured as follows in the drone motor according to the fourth or fifth embodiment: The first, second, and third cylindrical portions each have a first end and a second end. The first end is positioned on the first side in the axial direction. The second end is positioned on the second side in the axial direction. The first end of the third cylindrical portion cooperates with the second end of the first cylindrical portion to form a first labyrinth structure. The second end of the third cylindrical portion cooperates with the first end of the second cylindrical portion to form a second labyrinth structure.

[0012] The drone motor according to the seventh embodiment further comprises a first bearing member, a second bearing member, a biasing member, and a spacer in addition to the drone motor according to any of the fourth to sixth embodiments. The first bearing member is positioned radially between the stator frame and the rotating shaft. The second bearing member is positioned radially between the stator frame and the rotating shaft. The second bearing member is positioned axially at a distance from the first bearing member. The biasing member biases one of the inner and outer rings of the first bearing member so as to move away from the second bearing member. The spacer is positioned between the first bearing member and the second bearing member. The spacer supports the other of the inner and outer rings of the first bearing member in the axial direction.

[0013] The drone motor according to the eighth embodiment further comprises a balance adjustment plate in addition to the drone motor according to any of the first to seventh embodiments. The balance adjustment plate is detachably attached to the first rotor or the second rotor.

[0014] The motor drive system according to the ninth embodiment comprises a drone motor according to any of the first to eighth embodiments, a first inverter, and a second inverter. The first inverter is electrically connected to the first motor. The second inverter is electrically connected to the second motor. [Effects of the Invention]

[0015] According to the present invention, it is possible to suppress drone crashes caused by motor failure. [Brief explanation of the drawing]

[0016] [Figure 1] Perspective view of a motor for a drone. [Figure 2] Plan view of a motor for a drone. [Figure 3] Cross-sectional view along line AA in Figure 2. [Figure 4] Plan view of the stator frame. [Figure 5] A schematic cross-sectional view of the first arm. [Figure 6] A schematic cross-sectional view of the second arm.

Best Mode for Carrying Out the Invention

[0017] Hereinafter, the drone motor 100 and the motor drive system 200 according to this embodiment will be described with reference to the drawings. In the following description, the axial direction is the direction in which the rotation axis O of the drone motor 100 extends. The circumferential direction is the circumferential direction of a circle centered on the rotation axis O, and the radial direction is the radial direction of a circle centered on the rotation axis O. In this embodiment, the first side in the axial direction means the upper side in FIG. 1, and the second side in the axial direction means the lower side in FIG. 1.

[0018] FIG. 1 is a perspective view of the drone motor 100, FIG. 2 is a plan view of the drone motor 100, and FIG. 3 is a cross-sectional view taken along the line A-A of FIG. 2. As shown in FIGS. 1 to 3, the motor drive system 200 includes a drone motor 100, a first inverter 11, and a second inverter 12. The drone motor 100 has a rotating shaft 2, a first motor 3, a second motor 4, a stator frame 5, a first bearing member 6, a second bearing member 7, a biasing member 8, a spacer 9, and a balance adjustment plate 10.

[0019] The drone motor 100 is used, for example, in an industrial drone. The drone motor 100 is configured to rotate a propeller (not shown) of the drone. The propeller is disposed on the second side in the axial direction with respect to the drone motor 100. The propeller is attached to the lower part of the drone motor 100. The rotation axis O of the drone motor 100 extends in the vertical direction. That is, in this embodiment, the axial direction means the vertical direction.

[0020] The drone includes a plurality of such drone motors 100. Generally, the drone includes four such drone motors 100. Each drone motor 100 is attached to the main body portion of the drone via an arm or the like. The main body portion of the drone houses a battery, a control unit (including the first and second inverters 11 and 12), and the like.

[0021] <Stator Frame> FIG. 4 is a plan view of the stator frame 5. As shown in FIGS. 1 to 4, the stator frame 5 is non-rotatable. The stator frame 5 is attached to an arm (not shown) extending from the main body portion of the drone. The stator frame 5 has a support portion 51, a cover portion 52 (an example of a third cylindrical portion), and a first connecting portion 53.

[0022] The support portion 51 supports the first stator 31 of the first motor 3 and the second stator 41 of the second motor 4. The support portion 51 is cylindrical and extends in the axial direction. Specifically, the support portion 51 is double-cylindrical. The support portion 51 has an outer cylindrical portion 511 and an inner cylindrical portion 512.

[0023] The inner cylindrical portion 512 extends axially within the outer cylindrical portion 511. The outer cylindrical portion 511 and the inner cylindrical portion 512 are arranged at intervals in the radial direction. The outer cylindrical portion 511 and the inner cylindrical portion 512 are connected by a second connecting portion 513. The second connecting portion 513 may be a plurality of arms extending in the radial direction or an annular plate having a plurality of openings. A through hole 515 extending in the axial direction is formed in the second connecting portion 513.

[0024] The cover portion 52 is cylindrical. The cover portion 52 extends in the axial direction. The cover portion 52 is disposed radially outside the support portion 51. The cover portion 52 is disposed so as to surround the support portion 51. The cover portion 52 is arranged at a distance from the support portion 51 in the radial direction. The cover portion 52 is shorter in the axial direction than the support portion 51.

[0025] The cover portion 52 has a first end portion 521 and a second end portion 522 in the axial direction. The first end portion 521 is the end portion on the first side in the axial direction. That is, the first end portion 521 is disposed on the side of the first yoke 322 described later. The second end portion 522 is the end portion on the second side in the axial direction. That is, the second end portion 522 is the end portion on the side of the second yoke 422 described later.

[0026] The first connecting portion 53 connects the support portion 51 and the cover portion 52. The shape of the first connecting portion 53 is not particularly limited. For example, the first connecting portion 53 may be an annular plate having a plurality of openings 531, or it may be a plurality of arms extending in the radial direction.

[0027] <Rotating shaft, bearing members, biasing members, and spacers> The rotating shaft 2 extends axially. The rotating shaft 2 extends axially within the stator frame 5. More specifically, the rotating shaft 2 extends axially within the support portion 51. The rotating shaft 2 is rotatably positioned. The rotating shaft 2 is rotatably supported by the stator frame 5. More specifically, the rotating shaft 2 is supported by the stator frame 5 via a first bearing member 6 and a second bearing member 7.

[0028] The first bearing member 6 is positioned radially between the rotating shaft 2 and the stator frame 5. More specifically, the first bearing member 6 is positioned radially between the rotating shaft 2 and the support portion 51. The first bearing member 6 is attached to the first axial end of the support portion 51.

[0029] The second bearing member 7 is positioned radially between the rotating shaft 2 and the stator frame 5. More specifically, the second bearing member 7 is positioned radially between the rotating shaft 2 and the support portion 51. The second bearing member 7 is attached to the second axial end of the support portion 51. The second bearing member 7 is positioned axially at a distance from the first bearing member 6.

[0030] The biasing member 8 biases the outer ring of the first bearing member 6 toward the first axial direction. That is, the biasing member 8 biases the outer ring of the first bearing member 6 toward the direction away from the second bearing member 7. The biasing member 8 is an annular shape extending in the circumferential direction. The biasing member 8 is, for example, a wave washer or a disc spring. The biasing member 8 is positioned between the protrusion 514 that projects radially inward from the inner circumferential surface of the support portion 51 and the first bearing member 6.

[0031] The biasing member 8 biases the first bearing member 6 via the pressure plate 81. The pressure plate 81 is annular in shape and extends in the circumferential direction. The pressure plate 81 is in contact with the outer ring of the first bearing member 6. However, the pressure plate 81 is not in contact with the inner ring of the first bearing member 6.

[0032] The spacer 9 is positioned between the first bearing member 6 and the second bearing member 7. Specifically, the spacer 9 is positioned between the inner ring of the first bearing member 6 and the inner ring of the second bearing member 7. The spacer 9 is in contact with the inner ring of the first bearing member 6 and the inner ring of the second bearing member 7. The spacer 9 is cylindrical. The rotating shaft 2 extends inside the spacer 9. The spacer 9 rotates integrally with the rotating shaft 2.

[0033] The spacer 9 supports the inner ring of the first bearing member 6 in the axial direction. Specifically, the spacer 9 restricts the axial movement of the first bearing member 6 toward the second side. Because the spacer 9 is positioned in this way, the amount of deflection of the biasing member 8 when the first bearing member 6 is installed can be set to a predetermined amount.

[0034] <First Motor> The first motor 3 is positioned on the first axial side relative to the second motor 4. Specifically, the first motor 3 is positioned above the second motor 4. The first motor 3 has basically the same configuration as the second motor 4. The first motor 3 has a first stator 31 and a first rotor 32. The first motor 3 is a so-called outer rotor type motor.

[0035] The first stator 31 is positioned so as not to rotate. The first stator 31 is positioned on the second axial side relative to the first rotor 32. The first stator 31 is positioned so as to be covered by the first rotor 32. The first stator 31 is supported by the stator frame 5. In radial view, the first stator 31 overlaps with the first bearing member 6. The first stator 31 has a first stator core 311 and a plurality of first coil portions 312.

[0036] The first stator core 311 is supported by the stator frame 5. The first stator core 311 is attached to the first axial end of the stator frame 5. The first stator core 311 is positioned radially outward from the support portion 51 of the stator frame 5. That is, the first stator core 311 is positioned to surround the support portion 51. The first stator core 311 is supported by the support portion 51. The first stator core 311 is constructed by laminating multiple sheets of electrical steel.

[0037] The first coil section 312 is wound around the first stator core 311. More specifically, the first coil section 312 is wound around the teeth of the first stator core 311. An insulating layer 313 is interposed between the first coil section 312 and the first stator core 311.

[0038] The first rotor 32 is rotatably positioned. The first rotor 32 is configured to rotate the rotating shaft 2. That is, the first rotor 32 is attached to the rotating shaft 2. More specifically, the first rotor 32 is attached to the first axial end of the rotating shaft 2.

[0039] The first rotor 32 is positioned on the first axial side relative to the first stator 31. The first rotor 32 rotates integrally with the propeller. The first rotor 32 is configured to rotate the same propeller as the second rotor 42. The first rotor 32 has a first rotor frame 321, a first yoke 322 (an example of a first cylindrical section), and a plurality of first permanent magnets 323.

[0040] The first rotor frame 321 is configured to support the first yoke 322 and the first permanent magnet 323. The first rotor frame 321 is configured to rotate together with the first yoke 322 and the first permanent magnet 323. The first rotor frame 321 is rotatably supported on the stator frame 5. In detail, the first rotor frame 321 is supported on the stator frame 5 via a rotating shaft 2 and a first bearing member 6.

[0041] The first rotor frame 321 rotates together with the rotating shaft 2. The first rotor frame 321 is made of a separate component from the rotating shaft 2, but it may also be integrally formed with the rotating shaft 2 from a single component.

[0042] The first rotor frame 321 has a top plate portion 3211, a cylindrical portion 3212, and a protruding portion 3215. The top plate portion 3211 is disc-shaped. The top plate portion 3211 defines the upper surface of the drone motor 100. The top plate portion 3211 has a plurality of first openings 3213 and a plurality of first arms 3216.

[0043] Each first opening 3213 is spaced apart from each other in the circumferential direction. Each first opening 3213 is closed by a mesh-like plate 3214, such as perforated metal.

[0044] Each first arm 3216 is positioned between each first opening 3213 in the circumferential direction. That is, the first openings 3213 and the first arms 3216 are arranged alternately in the circumferential direction. The first arms 3216 extend radially.

[0045] Figure 5 is a schematic cross-sectional view of the first arm 3216. As shown in Figure 5, each first arm 3216 has a first inclined surface 3217 facing the first axial direction R1. The first inclined surface 3217 is inclined to face the first axial direction R1 and the first axial direction. In addition, each first arm 3216 has a second inclined surface 3218 facing the second axial direction R2. The second inclined surface 3218 is inclined to face the second axial direction R2 and the second axial direction.

[0046] Therefore, when the first rotor 32 rotates in the first rotation direction R1, an airflow directed axially toward the first direction is generated within the drone motor 100. On the other hand, when the first rotor 32 rotates in the second rotation direction R2, an airflow directed axially toward the second direction is generated within the drone motor 100. The first rotation direction R1 refers to the clockwise direction in Figure 2. The second rotation direction R2 refers to the rotation direction opposite to the first rotation direction R1, i.e., the counterclockwise direction in Figure 2.

[0047] The cylindrical portion 3212 extends from the outer peripheral end of the top plate portion 3211 to the second axial direction. The cylindrical portion 3212 is positioned radially outward relative to the first stator 31.

[0048] The protrusion 3215 projects from the top plate portion 3211 to the second axial side. The protrusion 3215 is cylindrical. The protrusion 3215 is in contact with the inner ring of the first bearing member 6. The inner ring of the first bearing member 6 is sandwiched in the axial direction by the protrusion 3215 and the spacer 9.

[0049] The first yoke 322 is cylindrical. The first yoke 322 is positioned radially outward relative to the first stator 31. The first yoke 322 is positioned to surround the first stator 31. The first yoke 322 is fixed to the cylindrical portion 3212 of the first rotor frame 321. The first yoke 322 is configured to rotate integrally with the first rotor frame 321.

[0050] The first yoke 322 has a first end 3221 and a second end 3222. The first end 3221 is the first end in the axial direction. The first end 3221 is located on the side furthest from the cover portion 52. That is, the first end 3221 is located on the side of the first rotor frame 321. The second end 3222 is the second end in the axial direction. That is, the first end 3221 is located on the side of the cover portion 52.

[0051] The second end 3222 of the first yoke 322 overlaps with the first end 521 of the cover portion 52 in a radial view. Furthermore, the second end 3222 of the first yoke 322 cooperates with the first end 521 of the cover portion 52 to form a first labyrinth structure.

[0052] In detail, the second end 3222 of the first yoke 322 has a recess on its inner circumferential surface. This recess is annular in shape extending in the circumferential direction and opens to a second side in the axial direction. The first end 521 of the cover portion 52 also has a recess on its outer circumferential surface. This recess is annular in shape extending in the circumferential direction and opens to a first side in the axial direction. Thus, the first labyrinth structure is formed by positioning the first end 521 of the cover portion 52 within the recess formed in the second end 3222 of the first yoke 322, and positioning the second end 3222 of the first yoke 322 within the recess formed in the first end 521 of the cover portion 52.

[0053] Each first permanent magnet 323 is supported by the first rotor frame 321. More specifically, each first permanent magnet 323 is mounted on the inner circumferential surface of the first yoke 322. Each first permanent magnet 323 is spaced apart from one another in the circumferential direction.

[0054] Each first permanent magnet 323 is positioned radially outward from the first stator 31. The first permanent magnets 323 are arranged to surround the first stator 31. Furthermore, the first permanent magnets 323 are spaced apart from the first stator 31 in the radial direction.

[0055] <Second Motor> The second motor 4 is positioned on the second axial side relative to the first motor 3. Specifically, the second motor 4 is positioned below the first motor 3. The second motor 4 has substantially the same configuration as the first motor 3. The second motor 4 is configured by inverting the first motor 3. The second motor 4 has a second stator 41 and a second rotor 42. The second motor 4 is a so-called outer rotor type motor.

[0056] The second stator 41 is positioned so as not to rotate. The second stator 41 is positioned on the first axial side relative to the second rotor 42. The second stator 41 is positioned so as to be covered by the second rotor 42. The second stator 41 is supported by the stator frame 5. In radial view, the second stator 41 overlaps with the second bearing member 7. The second stator 41 has a second stator core 411 and a plurality of second coil portions 412.

[0057] The second stator core 411 is supported by the stator frame 5. The second stator core 411 is attached to the second axial end of the stator frame 5. The second stator core 411 is positioned radially outward from the support portion 51 of the stator frame 5. That is, the second stator core 411 is positioned to surround the support portion 51. The second stator core 411 is supported by the support portion 51. The second stator core 411 is constructed by laminating multiple electromagnetic steel sheets.

[0058] The second coil section 412 is wound around the second stator core 411. More specifically, the second coil section 412 is wound around the teeth of the second stator core 411. An insulating layer 413 is interposed between the second coil section 412 and the second stator core 411.

[0059] The second rotor 42 is rotatably positioned. The second rotor 42 is configured to rotate the rotating shaft 2. That is, the second rotor 42 is attached to the rotating shaft 2. More specifically, the second rotor 42 is attached to the second axial end of the rotating shaft 2.

[0060] The second rotor 42 is positioned on the second axial side relative to the second stator 41. A propeller is attached to the second rotor 42. The second rotor 42 rotates integrally with the propeller. The second rotor 42 has a second rotor frame 421, a second yoke 422 (an example of a second cylindrical section), and a plurality of second permanent magnets 423.

[0061] The second rotor frame 421 is configured to support the second yoke 422 and the second permanent magnet 423. The second rotor frame 421 is configured to rotate together with the second yoke 422 and the second permanent magnet 423. The second rotor frame 421 is rotatably supported on the stator frame 5. In detail, the second rotor frame 421 is supported on the stator frame 5 via the rotating shaft 2 and the second bearing member 7.

[0062] The second rotor frame 421 rotates together with the rotating shaft 2. The second rotor frame 421 is made of a separate component from the rotating shaft 2, but it may also be integrally formed with the rotating shaft 2 from a single component.

[0063] The second rotor frame 421 has a plurality of through holes 424. Each through hole 424 can be, for example, a plurality of screw holes configured for screwing in a bolt 101. With this configuration, the second rotor frame 421 can be used as the first rotor frame 321.

[0064] The propeller is fixed to the second rotor frame 421 and rotates with the second rotor frame 421. For example, the second rotor frame 421 has a number of screw holes 424 into which bolts (not shown) are screwed. The propeller is fastened to the second rotor frame 421 by bolts.

[0065] The second rotor frame 421 has a bottom plate portion 4211, a cylindrical portion 4212, and a protruding portion 4215. The bottom plate portion 4211 is disc-shaped. The bottom plate portion 4211 has the same configuration as the top plate portion 3211 of the first rotor frame 321. The bottom plate portion 4211 defines the bottom surface of the drone motor 100. The bottom plate portion 4211 has a plurality of second openings 4213 and a plurality of second arms 4216.

[0066] Each second opening 4213 is spaced apart from each other in the circumferential direction. Each second opening 4213 is closed by a mesh-like plate 4214, such as perforated metal.

[0067] Each second arm 4216 is positioned between each second opening 4213 in the circumferential direction. That is, the second openings 4213 and the second arms 4216 are arranged alternately in the circumferential direction. The second arms 4216 extend radially.

[0068] Figure 6 is a schematic cross-sectional view of the second arm 4216. As shown in Figure 6, each second arm 4216 has a third inclined surface 4217 facing the first axial direction R1. The third inclined surface 4217 is inclined to face the first axial direction R1 and the first axial direction. In addition, each second arm 4216 has a fourth inclined surface 4218 facing the second axial direction R2. The fourth inclined surface 4218 is inclined to face the second axial direction R2 and the second axial direction.

[0069] Therefore, when the second rotor 42 rotates in the first rotation direction R1, an airflow directed towards the first axial direction is generated within the drone motor 100. On the other hand, when the second rotor 42 rotates in the second rotation direction R2, an airflow directed towards the second axial direction is generated within the drone motor 100.

[0070] The cylindrical portion 4212 extends from the outer peripheral end of the bottom plate portion 4211 toward the first axial direction. The cylindrical portion 4212 is positioned radially outward relative to the second stator 41.

[0071] The protrusion 4215 projects from the bottom plate portion 4211 to the first axial direction. The protrusion 4215 is cylindrical in shape. The protrusion 4215 is in contact with the inner ring of the second bearing member 7. The inner ring of the second bearing member 7 is sandwiched in the axial direction between the protrusion 4215 and the spacer 9. The outer ring of the second bearing member 7 is supported by the support portion 51 of the stator frame 5. More specifically, the outer ring of the second bearing member 7 is biased to the second axial direction by the support portion 51.

[0072] The second yoke 422 is cylindrical. The second yoke 422 is positioned radially outward relative to the second stator 41. The second yoke 422 is positioned so as to surround the second stator 41. The second yoke 422 is positioned on the second axial side relative to the first yoke 322. The second yoke 422 is positioned at a distance from the first yoke 322 in the axial direction. A cover portion 52 is positioned between the first yoke 322 and the second yoke 422 in the axial direction. In this way, the first yoke 322, the second yoke 422, and the cover portion 52 constitute the side wall of the drone motor 100.

[0073] The second yoke 422 is fixed to the cylindrical portion 4212 of the second rotor frame 421. The second yoke 422 is configured to rotate integrally with the second rotor frame 421.

[0074] The second yoke 422 has a first end 4221 and a second end 4222. The first end 4221 is the first end in the axial direction. That is, the first end 4221 is located on the cover portion 52 side. The second end 4222 is the second end in the axial direction. The second end 4222 is located on the side furthest from the cover portion 52. That is, the second end 4222 is located on the second rotor frame 421 side.

[0075] The first end 4221 of the second yoke 422 overlaps with the second end 522 of the cover portion 52 in a radial view. Furthermore, the first end 4221 of the second yoke 422 cooperates with the second end 522 of the cover portion 52 to form a second labyrinth structure.

[0076] In detail, the first end 4221 of the second yoke 422 has a recess on its inner circumferential surface. This recess is annular in shape extending in the circumferential direction and opens to a first side in the axial direction. The second end 522 of the cover portion 52 also has a recess on its outer circumferential surface. This recess is annular in shape extending in the circumferential direction and opens to a second side in the axial direction. Thus, the second labyrinth structure is formed by positioning the second end 522 of the cover portion 52 within the recess formed in the first end 4221 of the second yoke 422, and positioning the first end 4221 of the second yoke 422 within the recess formed in the second end 522 of the cover portion 52.

[0077] Each second permanent magnet 423 is supported by the second rotor frame 421. More specifically, each second permanent magnet 423 is mounted on the inner circumferential surface of the second yoke 422. Each second permanent magnet 423 is spaced apart from one another in the circumferential direction.

[0078] Each second permanent magnet 423 is positioned radially outward relative to the second stator 41. The second permanent magnets 423 are arranged to surround the second stator 41. Furthermore, the second permanent magnets 423 are spaced apart from the second stator 41 in the radial direction.

[0079] <Balance adjustment plate> The balance adjustment plate 10 is detachably attached to the first rotor 32. Alternatively, the balance adjustment plate may be detachably attached to the second rotor 42. The balance adjustment plate 10 is fastened to the first rotor frame 321 by a plurality of bolts 101. The first rotor frame 321 has a plurality of screw holes 324 into which the bolts 101 are threaded. The balance adjustment plate 10 can be removed by unscrewing the bolts 101.

[0080] If the assembled drone motor 100 is unbalanced, the balance adjustment plate 10 can be removed, and the appropriate parts of the balance adjustment plate 10 can be cut or drilled. Then, the balance adjustment plate 10 can be reattached to the first rotor frame 321 with bolts 101 to adjust the balance of the drone motor 100.

[0081] <First and Second Inverters> The first inverter 11 is electrically connected to the first motor 3. More specifically, the first inverter 11 is electrically connected to the first coil section 312 of the first stator 31 of the first motor 3. The cable connecting the first inverter 11 and the first coil section 312 extends from the outside to the inside of the drone motor 100 via the cover section 52. The first inverter 11 is configured to drive and control the first motor 3. The first inverter 11 converts DC power from the battery into AC power and supplies it to the first motor 3.

[0082] The second inverter 12 is electrically connected to the second motor 4. More specifically, the second inverter 12 is electrically connected to the second coil section 412 of the second stator 41 of the second motor 4. The cable connecting the second inverter 12 and the second coil section 412 extends from the outside to the inside of the drone motor 100 via the cover section 52. The second inverter 12 is configured to drive and control the second motor 4. The second inverter 12 converts DC power from the battery into AC power and supplies it to the second motor 4.

[0083] [Differentiation] Although embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications are possible without departing from the spirit of the invention. Furthermore, the following modifications can basically be applied simultaneously.

[0084] (a) In the above embodiment, recesses are formed on the inner circumferential surfaces of the second end 3222 of the first yoke 322 and the first end 4221 of the second yoke 422, and recesses are formed on the outer circumferential surfaces of the first end 521 and the second end 522 of the cover portion 52, but these configurations are not limited. For example, recesses may be formed on the outer circumferential surfaces of the second end 3222 of the first yoke 322 and the first end 4221 of the second yoke 422, and recesses may be formed on the inner circumferential surfaces of the first end 521 and the second end 522 of the cover portion 52.

[0085] (b) In the above embodiment, the first cylindrical portion is formed by the first yoke 322, but is not limited thereto. For example, the first cylindrical portion may be formed by the first rotor frame 321. That is, the first cylindrical portion may be formed by the cylindrical portion 3212 of the first rotor frame 321. In this case, the first yoke 322 is attached to the inner circumferential surface of the cylindrical portion 3212 of the first rotor frame 321. In this embodiment, the second cylindrical portion is formed by the second yoke 422, but similarly, the second cylindrical portion may be formed by the second rotor frame 421.

[0086] (c) In the above embodiment, the first motor 3 was controlled by the first inverter 11 and the second motor 4 was controlled by the second inverter 12, but the configuration of the drone motor 100 is not limited to this. For example, the first motor 3 and the second motor 4 may be controlled by a single inverter.

[0087] (d) In the above embodiment, the propeller was positioned on the second axial side of the drone motor 100, but the propeller may be positioned on the first axial side of the drone motor 100. That is, the propeller may be attached to the first rotor frame 321.

[0088] (e) The balance adjustment plate 10 was attached to the first rotor 32 rather than the second rotor 42 to which the propeller is attached, but it may also be attached to the second rotor 42 to which the propeller is attached rather than the first rotor 32.

[0089] (f) In the above embodiment, the first rotation direction R1 meant clockwise in Figure 2 and the second rotation direction R2 meant counterclockwise in Figure 2, but the definitions of the first rotation direction R1 and the second rotation direction R2 are not limited to these. That is, the first rotation direction R1 may mean counterclockwise in Figure 2 and the second rotation direction R2 may mean clockwise in Figure 2. [Explanation of Symbols]

[0090] 2: Rotating shaft 3: First motor 31: First Status 32: First Rotor 321: First rotor frame 3211: Top panel 3213: First opening 3216: First Arm 3217: 1st slope 3218 :Second slope 322: First York 323: First permanent magnet 4: Second motor 41: Second Status 42: Second Rotor 421: Second rotor frame 4211: Bottom plate part 4213: Second opening 4216: Second Arm 4217: Third slope 4218: 4th slope 422: Second York 423: Second permanent magnet 5: Stator frame 52: Cover section 6: First bearing member 7: Second bearing member 8: Biasing member 9: Spacer 10: Balance adjustment plate 11: First Inverter 12: Second Inverter 100: Motor for drones 521: First end 522: Second end 3221: First end 3222 :Second end 4212: Cylindrical section 4221: First end 4222 :Second end

Claims

1. A rotating shaft extending in the axial direction, A first motor having a first rotor and a first stator configured to rotate the aforementioned rotating shaft, A second motor having a second rotor and a second stator configured to rotate the aforementioned rotating shaft, A motor for drones, equipped with the following features.

2. The first rotor comprises a first rotor frame, a cylindrical first yoke attached to the first rotor frame, and a plurality of first magnets attached to the inner circumferential surface of the first yoke. Each of the first magnets is arranged radially outward with respect to the first stator. The second rotor comprises a second rotor frame, a cylindrical second yoke attached to the second rotor frame, and a plurality of second magnets attached to the inner circumferential surface of the second yoke. Each of the second magnets is positioned radially outward with respect to the second stator. A motor for a drone according to claim 1.

3. The first rotor frame has a top plate portion, The second rotor frame has a bottom plate portion, The top plate portion has a plurality of first openings and at least one first arm positioned between each of the first openings. The first arm has a first inclined surface facing the first axial side in the first rotation direction and a second inclined surface facing the second axial side in the second rotation direction. The bottom plate portion has a plurality of second openings and at least one second arm positioned between each of the second openings. The second arm has a third inclined surface facing the first axial direction in the first rotation direction and a fourth inclined surface facing the second axial direction in the second rotation direction. A motor for a drone according to claim 2.

4. Stator frame supporting the first stator and the second stator, Furthermore, The first rotor has a first cylindrical portion that is positioned radially outward with respect to the first stator, The second rotor has a second cylindrical portion that is positioned radially outward with respect to the second stator, The stator frame has a third cylindrical portion that is positioned between the first cylindrical portion and the second cylindrical portion in the axial direction. A motor for a drone according to claim 1.

5. Each of the first, second, and third cylindrical portions has a first end located on the first axial side and a second end located on the second axial side. The first end of the third cylindrical portion overlaps with the second end of the first cylindrical portion in a radial view. The second end of the third cylindrical portion overlaps with the first end of the second cylindrical portion in a radial view. A motor for a drone according to claim 4.

6. Each of the first, second, and third cylindrical portions has a first end located on the first axial side and a second end located on the second axial side. The first end of the third cylindrical portion cooperates with the second end of the first cylindrical portion to form a first labyrinth structure. The second end of the third cylindrical portion cooperates with the first end of the second cylindrical portion to form a second labyrinth structure. A motor for a drone according to claim 4.

7. A first bearing member is positioned radially between the stator frame and the rotating shaft, A second bearing member is positioned radially between the stator frame and the rotating shaft, and is positioned axially at a distance from the first bearing member, A biasing member that biases one of the inner ring and outer ring of the first bearing member so as to move away from the second bearing member, A spacer is disposed between the first bearing member and the second bearing member, and supports the other of the inner and outer rings of the first bearing member in the axial direction. Furthermore, A motor for a drone according to claim 4.

8. The motor for a drone according to claim 1, further comprising a balance adjustment plate that is detachably attached to the first rotor or the second rotor.

9. A motor for a drone according to any one of claims 1 to 8, A first inverter electrically connected to the first motor, A second inverter electrically connected to the second motor, A motor-driven system equipped with the following features.

Images