drones

Abstract

To provide an unmanned aircraft that can improve dustproof or waterproof performance. [Solution] The unmanned aircraft 1 comprises a housing 3 having an open space S1 to the outside, a cover 7 covering the open space S1 to the outside, and a motor 6 positioned inside the space S1. The motor 6 comprises a shaft 8 having a portion that protrudes from the cover 7 in the direction from the housing 3 toward the cover 7, a rotor 61 rotatably supported by the cover 7 together with the shaft 8, and a stator 62 surrounded by the cover 7 and the rotor 61.

Description

Technical Field

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[0001] The present invention relates to a drone.

Background Art

[0002] For example, Patent Document 1 discloses a flying object having a plurality of frame parts. At the tip of each frame part, a propeller and a motor for rotating the propeller are incorporated. Outside air is taken into each frame part by a blower fan arranged at the air intake and exhaust port at the tip of each frame part.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Rain, dust, etc. are sucked into each frame part together with outside air from the air intake and exhaust port. When the motor is, for example, an outer rotor type, a predetermined clearance is formed between the rotor and the stator. It is important to prevent the intrusion of rain, dust, etc. into the motor through this clearance.

[0005] The present invention has been made in view of the above problems, and one of the problems is to provide a drone capable of improving dust-proof performance or waterproof performance.

Means for Solving the Problems

[0006] An unmanned aircraft according to one aspect of the present invention comprises a housing having an open space to the outside, a cover covering the open space to the outside, and a motor disposed inside the space, wherein the motor comprises a shaft having a portion protruding from the cover in the direction toward the cover from the housing, a rotor rotatably supported by the cover together with the shaft, and a stator surrounded by the cover and the rotor. [Brief explanation of the drawing]

[0007] [Figure 1] 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. [Figure 2] This is an exploded perspective view showing a schematic structure of a propulsion device 2 in one specific example. [Figure 3] This is a cross-sectional view along line 3-3 in Figure 1. [Figure 4] This is a partially enlarged cross-sectional view along line 4-4 in Figure 1. [Figure 5] This is a partially enlarged cross-sectional view along line 5-5 in Figure 4. [Figure 6] This is a partially enlarged cross-sectional view of a propulsion device 2, corresponding to Figure 3, which is a specific example. [Figure 7] This is a cross-sectional view of the propulsion device 2 relating to another specific example, corresponding to Figure 3. [Modes for carrying out the invention]

[0008] An 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 an embodiment of the present invention. The unmanned aircraft 1 is a so-called multicopter having a plurality of propulsion devices 2. The unmanned aircraft 1 comprises a main body (not shown), a plurality of arms (not shown), and a plurality of propulsion devices 2. The main body is, for example, located at the center of the unmanned aircraft 1. The plurality of arms extend from the main body in predetermined directions. Each propulsion device 2 is attached, for example, to the tip of each arm.

[0009] In the following description of the embodiments relating to the unmanned aircraft 1, terms such as "up," "down," "front," and "rear" are used for convenience. However, the terms "up" and "down" do not necessarily correspond to up and down in the direction of gravity, and are defined for convenience when considering the propulsion device 2 alone. Similarly, the terms "front" and "rear" do not necessarily correspond to front and rear in the direction of travel of the unmanned aircraft 1, and are defined for convenience when considering the propulsion device 2 alone.

[0010] The housing of the main body of the unmanned aircraft 1 incorporates components such as a control device for driving the unmanned aircraft 1, a battery, various sensors, and a camera. Multiple arms extend radially from this housing, for example. The arms are formed from, for example, cylindrical metal or resin materials. Wiring housed in the internal space of the arms connects the battery and other components incorporated in the main body to the propulsion device 2. In this way, power is supplied from the battery in the main body to the propulsion device 2. For example, instead of an arm with one end, a T-shaped arm with two ends may be used.

[0011] Figure 2 is an exploded perspective view schematically showing the structure of a propulsion device 2 according to one specific example. Figure 3 is a cross-sectional view along line 3-3 in Figure 1. Referring together to Figures 1 to 3, the propulsion device 2 according to one specific example comprises a housing 3, a motor unit 4, and a propeller 5. In this example, the housing 3 has a generally cylindrical outer shape with an axis x1 extending in the front-rear direction of the propulsion device 2 as its central axis. The housing 3 comprises a main body 31 and a lid 32. The main body 31 and the lid 32 are formed from, for example, a metal material or a resin material.

[0012] In this example, along axis x1, the front end of the housing 3 has a shape that gradually decreases in diameter as it moves forward. Also along axis x1, the rear end of the housing 3 has a shape that gradually decreases in width as it moves backward. A hollow first space S1 is formed inside the main body 31. The first space S1 opens to the outside through a first opening 33, a second opening 34, and a third opening 35. The first opening 33 is formed on the upper side of the main body 31 of the housing 3. In this example, the first opening 33 is defined within a recess 36 formed on the upper side of the main body 31. The second opening 34 is formed on the lower side of the main body 31. The third opening 35 is formed at the rear end of the main body 31. Note that the above shape of the housing 3 is just an example, and the housing 3 may have other shapes as long as it has at least the first opening 33 and the third opening 35.

[0013] The motor unit 4 is positioned in the upper recess 36 of the main body 31, thereby covering the first opening 33. In this way, the motor unit 4 is positioned inside the first space S1. That is, the first opening 33 is closed by the motor unit 4. The second opening 34 is covered by the lid 32. That is, the second opening 34 is closed by the lid 32. The lid 32 may be detachably attached to the main body 31. On the other hand, an arm (not shown) extending from the main body is attached to the third opening 35. In this way, the third opening 35 is closed by the arm.

[0014] The motor unit 4 includes a motor 6 and a cover 7. In this example, the cover 7 is positioned above the motor 6. The cover 7 is attached to the shaft 8 of the motor 6, which protrudes above the cover 7. The cover 7 is attached to the bottom surface 37 of the recess 36 of the main body 31. In this way, the cover 7 covers the first opening 33. The cover 7 is attached to the main body 31 by fixing members such as one or more bolts 71, in this example four bolts. Since the motor 6 is positioned below the cover 7, the motor 6 is housed inside the first space S1.

[0015] The propeller 5 is attached to the shaft 8 of the motor 6. The motor 6 allows the propeller 5 to rotate around a rotation axis x2 that is perpendicular to the axis x1. In this example, the propeller 5 consists of a pair of blades 51, 51 extending in opposite directions perpendicular to the rotation axis x2. Other propellers with different numbers of blades may also be used. The propulsion system 2 is configured to generate lift and thrust for the unmanned aircraft 1 by the rotation of the propeller 5 around the rotation axis x2.

[0016] Figure 4 is a partially enlarged cross-sectional view along line 4-4 in Figure 1. The cover 7 has a cover body 72 and a pusher 73. The cover body 72 has a flat plate portion (hereinafter referred to as the "flat plate portion") 74 that extends along a plane perpendicular to the axis of rotation x2. The flat plate portion 74 is formed in an annular shape around the axis of rotation x2. The cover 7 is received by a part of the lower surface of the flat plate portion 74 on the bottom surface 37 of the recess 36 of the main body 31 of the housing 3. The bolt 71 is screwed into the main body 31 through a through hole 74a (see Figure 2) formed in the flat plate portion 74. The cover body 72 and the pusher 73 are made of, for example, a metal material or a resin material.

[0017] The cover body 72 has an inner circumference portion (hereinafter referred to as the "inner circumference portion") 75 and an outer circumference portion (hereinafter referred to as the "outer circumference portion") 76 that extend downward from the lower surface of the flat plate portion 74. Both the inner circumference portion 75 and the outer circumference portion 76 are formed in a cylindrical shape with the rotation axis x2 as the central axis. The outer circumference surface of the inner circumference portion 75 faces the inner circumference surface of the outer circumference portion 76 in the radial direction perpendicular to the rotation axis x2. In this example, the inner circumference portion 75 extends downward from the inner circumference end of the flat plate portion 74. A flat annular pusher 73 is positioned at the inner circumference end of the flat plate portion 74. Details of the pusher 73 will be described later.

[0018] The motor 6 is a so-called outer rotor type motor. The motor 6 has a shaft 8, a rotor 61, and a stator 62. The rotor 61 is attached to the shaft 8. On the other hand, the stator 62 is attached to the cover 7. The shaft 8 is rotatably supported about the rotation axis x2 with respect to the cover 7, that is, the stator 62, via a pair of bearings 9, 9 in the direction of the rotation axis x2 (hereinafter referred to as the "rotation axis direction"). The bearing 9 is, for example, a ball bearing. However, other bearings other than, for example, ball bearings may be used for the bearing 9.

[0019] The shaft 8 has a shaft-like portion (hereinafter referred to as the "shaft portion") 81 and a disk-shaped flange 82. The shaft portion 81 and the flange 82 are integrally formed from, for example, a metal material. The shaft 8 is held by the inner rings of the pair of bearings 9, 9 at the shaft portion 81. The outer rings of the bearings 9, 9 are held on the inner peripheral surface of the inner peripheral portion 75. Each bearing 9 is, for example, fitted and fixed to the inner peripheral surface of the inner peripheral portion 75 or the outer peripheral surface of the shaft portion 81. An adhesive may be used for fixing. Thus, a part of the cover 7, that is, the inner peripheral portion 75, houses the bearings 9, 9 that rotatably support the shaft 8 with respect to the cover 7.

[0020] The pusher 73 is formed in a flat annular shape around the rotation axis x2. A male thread is cut on the outer peripheral surface of the pusher 73, while a female thread is cut on the inner peripheral surface at the upper end of the inner peripheral portion 75. As a result, the pusher 73 is attached to the cover body 71 by being screwed into the upper end of the inner peripheral portion 75 around the rotation axis x2. Thus, the pusher 73 can apply a predetermined preload to the outer ring of the upper bearing 9 in the rotation axis direction. The end portion on the inner peripheral side of the pusher 73 faces the outer peripheral surface of the shaft portion 81 of the shaft 8 with a predetermined gap therebetween.

[0021] The flange 82 extends radially from the upper end of the shaft portion 81 in a direction orthogonal to the rotation axis x2 and is formed in a flat disk shape. In the radial direction, the dimension of the flange 82 is larger than that of the shaft portion 81. A part of the shaft portion 81 and the flange 82 protrude from the cover 7 in the direction from the housing 3 toward the cover 7, in this example, in the upward direction in the rotation axis direction. The propeller 5 is attached to the upper surface of the flange 82. Fixing members (not shown) such as bolts may be used for the attachment.

[0022] The rotor 61 has a holder 63, a yoke 64, and a magnet 65. The holder 63 is attached to the lower end of the shaft portion 81 of the shaft 8. The holder 63 is formed, for example, in a disk shape with the rotation axis x2 as the central axis. The holder 63 is formed, for example, from a metal material or a resin material. A cylindrical yoke 64 with the rotation axis x2 as the central axis is attached to the outer peripheral side end of the holder 63. The yoke 64 is formed, for example, using a magnetic material. A cylindrical magnet 65 with the rotation axis x2 as the central axis is attached to the inner peripheral surface of the yoke 64. The magnet 65 is, for example, a permanent magnet.

[0023] In this example, the upper ends of the yoke 64 and the magnet 65 face the lower surface of the flat plate portion 74 of the cover body 72 of the cover 7 with a predetermined gap therebetween in the rotation axis direction. Also, the outer peripheral surface of the yoke 64 faces the inner surface of the main body 31 of the housing 3 with a predetermined gap therebetween in the radial direction. Further, the inner peripheral surface of the magnet 65 faces the outer peripheral surface of the outer peripheral portion 76 of the cover 7 with a predetermined gap therebetween. Also, the lower surface of the holder 63 faces the lid 32 of the housing 3 with a first space S1 therebetween in the rotation axis direction. The rotor 61 is rotatably supported by the cover 7 together with the shaft 8.

[0024] As shown in Figures 2 to 4, in the radial direction, the flat plate portion 74 of the cover body 72 of the cover 7 extends larger than the first opening 33 and the motor 6. That is, the flat plate portion 74 covers the entire circumference of the first opening 33 around the axis of rotation x2. Since the motor 6 is housed in the first opening 33, the flat plate portion 74 is larger than the motor 6 in the radial direction. In a plan view from above along the axis of rotation x2, the contour of the motor 6 is positioned within the contour of the flat plate portion 74. Furthermore, the motor 6 is positioned upside down compared to the conventional arrangement where the holder is positioned on the upper side and extends cylindrically downward from the holder.

[0025] Figure 5 is a partially enlarged cross-sectional view along the line 5-5 in Figure 4. Referring to both Figures 4 and 5, the stator 62 is fixed to the outer circumferential surface of the outer periphery 76 of the cover 7. The stator 62 has a stator core 66 as a magnetic material, a plurality of coils 67, and an insulator 68. The stator core 66 is formed, for example, from a laminate of magnetic material. The stator core 66 has a cylindrical portion (hereinafter referred to as the "cylindrical portion") 66a and a plurality of teeth 66b extending radially outward from the outer circumferential surface of the cylindrical portion 66a. The stator core 66 is held by the inner circumferential surface of the cylindrical portion 66a to the outer circumferential surface of the outer periphery 76 of the cover 7. In this way, the stator 62 is surrounded by the rotor 61 and the cover 7.

[0026] A coil 67 is wound around each tooth 66b, which is arranged circumferentially around the rotation axis x2. An insulator 68, made of an insulating material such as resin, is placed between the teeth 66b and the coil 67. In this way, electrical insulation is established between the stator core 66 and the coil 67. The magnetic poles of the teeth 66b of the stator core 66 face the magnet 65 of the rotor 61 with a predetermined magnetic gap in the radial direction. When current is supplied to the coil 67, a magnetic interaction is generated between the coil 67 and the magnet 65. This magnetic interaction allows the magnet 65, i.e., the rotor 61 and the shaft 8, to rotate around the rotation axis x2.

[0027] As shown in Figure 4, a heat dissipation member 69 is sandwiched between the upper end of the coil 67 and the lower surface of the cover body 72 of the cover 7. The heat dissipation member 69 is a heat conductive material that is, for example, clay-like or grease-like, and is fluid while maintaining its shape. Heat conductive materials include, for example, resin materials such as EPDM and silicone. The heat dissipation member 69 can make gapless contact with the coil 67 and the cover body 72. In this example, the heat dissipation member 69 is arranged in a continuous annular shape in the circumferential direction between the coil 67 and the cover body 72. In this way, the heat dissipation member 69 can transfer heat from the coil 67 to the cover body 72.

[0028] Returning to Figures 4 and 5, an annular second space S2 is formed on the inner side, or inner circumference, of the stator 62 in the radial direction. Specifically, the second space S2 is formed between the inner circumference 75 and the outer circumference 76 of the cover 7. This second space S2 is connected to the first space S1 in the radial direction through the magnetic gap between the rotor 61 and the stator 62 and the gap between the rotor 61 and the cover 7. In other words, in the motor unit 4, the second space S2, which is the internal space inside the motor 6, and the first space S1, which is the external space outside the motor 6, are connected to each other.

[0029] In the unmanned aircraft 1 described above, the motor unit 4 is located in a recess 36 of the main body 31 of the housing 3. The first opening 33 formed in the recess 36 is covered by a cover 7. The motor 6, supported by the cover 7, is located inside the first space S1 within the housing 3. In other words, the motor 6 is arranged in a reversed position in the rotation axis direction compared to a conventional outer rotor type motor with the holder 63 positioned on the upper side. As a result, even if rain or dust falls on the propulsion system 2 during flight, for example, the cover 7 can reliably prevent rain, dust, etc. from entering the first space S1, i.e., the motor 6. In this way, the dustproof or waterproof performance of the unmanned aircraft 1 can be improved.

[0030] Figure 6 corresponds to Figure 3 and is a partially enlarged cross-sectional view of a propulsion device 2 according to one specific example. As shown in Figure 6, the second space S2 formed on the inner circumference side of the stator 62 is surrounded by the cover 7 and the holder 63. This second space S2 is connected to the first space S1 through the magnetic gap between the rotor 61 and the stator 62, the gap between the teeth 66b in the circumferential direction, and the gap between the rotor 61 and the cover 7. As a result, when the rotor 61 rotates around the rotation axis x2, air can enter and exit between the first space S1 and the second space S2 as indicated by arrow A. In this way, for example, heated air generated by the coil 67 can be discharged from the second space S2 towards the first space S1.

[0031] Figure 7 corresponds to Figure 3 and is a cross-sectional view of a propulsion device 2 relating to another specific example. As shown in Figure 7, in the unmanned aircraft 1, for example, the propulsion device 2 is attached to the tip of an arm 10. The arm 10 is formed, for example, in a hollow cylindrical shape. A fan motor 11 is positioned inside the arm 10 at a predetermined location along the axis x1. The fan motor 11 can generate airflow along the axis x1 by the rotation of a fan (not shown) around the axis x1. In this example, the fan motor 11 can generate airflow directed towards the inside of the housing 3 of the propulsion device 2 and airflow directed towards the outside of the housing 3.

[0032] In this way, the fan motor 11 generates an airflow, for example, from the first space S1 to the second space S2. As a result, cool air from the first space S1 can be sent into the second space S2 inside the motor 6. This airflow can be used to cool the coil 67 of the motor 6. On the other hand, the fan motor 11 can also generate an airflow, for example, from the second space S2 to the first space S1. This airflow can release the heated air generated by the coil 67 towards the first space S1. The fan motor 11 may be attached to, for example, the underside of the housing of the main body of the unmanned aircraft 1.

[0033] 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.

[0034] 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.

[0035] 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. [Explanation of Symbols]

[0036] 1 Unmanned aircraft, 2 Propulsion system, 3 Housing, 31 Main body, 32 Cover, 33 First opening (opening), 34 Second opening, 35 Third opening, 36 Recess, 37 Bottom surface, 4 Motor unit, 5 Propeller, 51 Blade, 6 Motor, 61 Rotor, 62 Stator, 63 Holder, 64 Yoke, 65 Magnet, 66 Stator core, 66a Cylindrical part (cylindrical section), 66b Teeth, 67 Coil, 68 Insulator, 69 Heat dissipation member, 7 Cover, 71 Bolt (fixing member), 72 Cover body, 73 Pusher, 74 Flat plate part (flat plate section), 74a Through hole, 75 Inner circumference part (inner circumference section), 76 Outer circumference part (outer circumference section), 8 Shaft, 81 Axial part (shaft section), 82 Flange, 9 Bearing, 10 Arm, 11 fan motor, S1 first space (space), S2 second space, x1 axis, x2 rotation axis

Claims

1. A housing having an open space on the outside, A cover that covers the space that is open to the outside, The motor is located inside the aforementioned space, The aforementioned motor is A shaft having a portion that protrudes from the cover in the direction from the housing toward the cover, Along with the shaft, a rotor is rotatably supported by the cover, An unmanned aircraft comprising a stator enclosed by the cover and the rotor.

2. A portion of the cover houses a bearing that rotatably supports the shaft relative to the cover. The unmanned aircraft according to claim 1.

3. The stator is fixed to the cover. The unmanned aircraft according to claim 1 or 2.

4. The aforementioned space that opens to the outside is referred to as the first space, In the radial direction, the second space formed inside the stator and the first space are connected. An unmanned aircraft according to any one of claims 1 to 3.

5. The propeller is attached to the portion protruding from the aforementioned cover, An unmanned aircraft according to any one of claims 1 to 4.

6. The portion protruding from the cover is provided with a flange. The unmanned aircraft according to claim 5, wherein the propeller is attached to the flange.

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