Drone

Abstract

To improve a cooling structure of a motor for a drone.SOLUTION: A drone contains: a stator; a rotor that is opposite via the stator and a gap; a stator case that houses the stator; a thermal converter that is arranged to one side of a shaft direction of the stator case; and a rotational wing that is rotated by a rotation of the rotor. The stator case includes a coolant path which is extended to a peripheral direction and in which a coolant flows. The thermal converter includes: a thermal conversion part that performs a thermal conversion of the coolant; and a pump part that generates a circulation of the coolant between the coolant path and the thermal conversion part. The thermal conversion part performs a thermal conversion with wind due to the rotation of the rotational wing and the coolant.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a drone. [Background technology]

[0002] Conventionally, there are known flying objects with rotors, generally called drones. A motor is used to rotate the rotors of the drones. A motor is an example of a rotating machine. In such motors, cooling the heat generated in the stator and other components is an important issue.

[0003] Patent Document 1 discloses a propeller device for driving a ship. This propeller device has a structure in which the motor rotor and the propeller are integrated, and a stator is arranged on the outer periphery. Since this propeller device is intended for marine use, it is expected that the stator will be cooled by seawater. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-245889 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the cooling effect of seawater cannot be obtained for motors that rotate propellers used in the air, such as drones. Furthermore, motors for drones are particularly required to be small and lightweight, and a cooling structure that can accommodate this is required.

[0006] For this reason, there was previously room for improvement in the cooling structure of drone motors.

[0007] The present invention aims to improve the cooling structure of a motor for a drone. [Means for solving the problem]

[0008] A drone according to one embodiment of the present invention comprises a stator, a rotor facing the stator across a gap, a stator case that houses the stator, a heat exchanger arranged on one axial side of the stator case, and a rotor that rotates due to rotation of the rotor, wherein the stator case has a refrigerant flow path extending circumferentially and through which a refrigerant flows, the heat exchanger has a heat exchange section that performs heat exchange of the refrigerant, and a pump section that generates a flow that circulates the refrigerant between the refrigerant flow path and the heat exchange section, and the heat exchange section performs heat exchange between the wind generated by the rotation of the rotor and the refrigerant.

[0009] In the drone of one aspect described above, the heat exchanger is arranged on the intake side of the rotor.

[0010] In the drone of one aspect described above, the pump unit is driven by rotation of the rotor.

[0011] In one aspect of the drone described above, the rotating wing is integral with the rotor.

[0012] In one aspect of the drone described above, the drone is characterized in that it has a wind guidance section that guides the wind generated by the rotation of the rotor to the heat exchange section.

[0013] In one aspect of the drone described above, the air guidance section is a cylindrical member that covers at least the radially outer side of the heat exchange section.

[0014] In one aspect of the drone described above, the air guidance section is on one axial side of the heat exchange section and blocks at least a portion of the area other than the area axially opposite the heat exchange section. Effect of the Invention

[0015] According to one aspect of the present invention, it is possible to improve the cooling structure of a motor for a drone. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view of a drone 100 according to a first embodiment of the present invention. [Diagram 2] This is an oblique view of the main part 105 of the drone 100 with the wind guide members 101 and 102 removed. [Diagram 3] 1 is a perspective view showing the main part 105 with the -Z side visible. [Figure 4] FIG. 2 is an exploded perspective view showing a main part 105. [Diagram 5] This is a plan view of the drone 100 seen from the +Z side. [Figure 6] 1 is a plan cross-sectional view of the drone 100 taken at the position of a refrigerant flow path extending radially within the leg 112. [Figure 7] 2 is an enlarged cross-sectional plan view showing the vicinity of a pump portion 300. FIG. [Figure 8] 1 is a side cross-sectional view of the drone 100 taken at the position of a coolant flow path extending axially within the leg 112. [Figure 9] FIG. 1 is a plan cross-sectional view of the drone 100, taken along a line perpendicular to the axial direction within the stator case 120 and cutting the drone 100 at the position of a refrigerant flow path that extends circumferentially. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, a rotating machine according to an embodiment of the present invention and a drone using the rotating machine will be described with reference to the drawings. Note that in the following drawings, the scale and number of each structure may differ from the actual structure in order to make each component easier to understand.

[0018] In addition, in the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional Cartesian coordinate system. In the XYZ coordinate system, the Z-axis direction is parallel to the axial direction of the central axis J shown in FIG. 1. The Y-axis direction is parallel to the radial direction of the central axis J in which the leg 112 in FIG. 1 extends. The X-axis direction is perpendicular to both the Z-axis direction and the Y-axis direction. In each of the X-axis direction, the Y-axis direction, and the Z-axis direction, the side indicated by the arrow in the drawing is the + side, and the opposite side is the - side.

[0019] In the following description, the positive side (+Z side) in the Z-axis direction is referred to as "one side", and the negative side (-Z side) in the Z-axis direction is referred to as "the other side". Note that "one side" and "the other side" are names used simply for the purpose of description and do not limit the actual positional relationship and direction. Unless otherwise specified, the direction parallel to the central axis J (Z-axis direction) is simply referred to as "axial direction", the radial direction centered on the central axis J is simply referred to as "radial direction", and the circumferential direction centered on the central axis J, i.e., around the axis of the central axis J, is simply referred to as "circumferential direction". In the radial direction, the side approaching the central axis J is referred to as "radially inner side", and the side moving away from the central axis J is referred to as "radially outer side". In the circumferential direction, the clockwise side when viewed from the +Z side to the -Z side is referred to as "one circumferential side", and the counterclockwise side is referred to as "the other circumferential side".

[0020] In this specification, "extending in the axial direction" includes not only extending strictly in the axial direction (Z-axis direction) but also extending in a direction tilted by less than 45° with respect to the axial direction. In addition, in this specification, "extending in the radial direction" includes not only extending strictly in the radial direction, i.e., in a direction perpendicular to the axial direction (Z-axis direction), but also extending in a direction tilted by less than 45° with respect to the radial direction. In addition, "parallel" includes not only strictly parallel but also tilted by an angle of less than 45°. In addition, "expanding in a direction perpendicular to the axial direction" includes not only strictly expanding in a direction perpendicular to the axial direction (Z-axis direction), but also expanding in a direction tilted by less than 45° with respect to the direction perpendicular to the axial direction (Z-axis direction).

[0021] First Embodiment 1 is a perspective view of a drone according to a first embodiment of the present invention. The drone 100 has a motor 200 and a rotor 151. The motor 200 is an example of a rotary machine. The drone 100 flies by receiving lift generated by the rotation of the rotor 151.

[0022] The motor 200 has a stator 180 (see FIG. 4) housed in the stator case 120, a rotor 150 facing the stator 180 across a gap, and a shaft 152. The shaft 152 is a rotating shaft of the motor 200 that extends in the axial direction along the central axis J. In this embodiment, the rotor 151 is integral with the rotor 150 and the shaft 152, and when the rotor 150 rotates about the shaft 152, the rotor 151 also rotates.

[0023] The drone 100 also has a heat exchanger 110 arranged on one axial side of the stator case 120, and air guide members 101 and 102. The heat exchanger 110 has an axis portion 111 coaxial with the shaft 152, and legs 112, 113, and 114 extending radially from the axis portion 111. The air guide members 101 and 102 are an example of an air guide portion that guides the wind generated by the rotation of the rotor 151 to the legs 112 that function as a heat exchange portion of the heat exchanger 110.

[0024] 2 is a perspective view of the main part 105 with the air guide members 101 and 102 removed from the drone 100 in FIG. 1. Each of the legs 112, 113, and 114 of the heat exchanger 110 extends radially from the shaft part 111, then extends to the other axial side and stands on a surface on one axial side of the stator case 120. Each of the legs 112, 113, and 114 is fixed to the surface on one axial side of the stator case 120 by adhesive, welding, or the like. As will be described in detail later, the leg 112 functions as a heat exchanger that exchanges heat with the refrigerant.

[0025] Fig. 3 is a perspective view showing the main part 105 in a direction in which the -Z side is visible. A stator cover 190 is disposed on the other axial side of the stator case 120. Fig. 4 is an exploded perspective view showing the main part 105 in an exploded state. The shaft 152 is fixed to the shaft part 111 via a bearing 140. The impeller 130 is fixed to one axial end of the shaft 152. The shaft part 111 of the heat exchanger 110 has a bottomed cylindrical shape having a bottom on one axial side, and the impeller 130 is housed within the cylinder of the shaft part 111.

[0026] The rotor 150 has a magnet 160 and a magnet cover 170 that prevents the magnet 160 from falling off. The stator 180 has a stator core 181 and a winding 182 wound around the stator core 181. The rotor 150 is disposed radially inside the stator 180 and faces the stator 180 in the radial direction across a gap. In this embodiment, the motor 200 is a radial gap motor, but the present invention is also applicable to an axial gap motor.

[0027] FIG. 5 is a plan view of the drone 100 seen from the +Z side. FIG. 6 is a plan sectional view of the drone 100 cut at the position of the refrigerant flow path extending radially inside the leg 112. The heat exchanger 110 has a pump section 300. The shaft section 111 of the heat exchanger 110 functions as a pump casing of the pump section 300. The cylindrical interior of the shaft section 111 of the heat exchanger 110 functions as a refrigerant flow path 115 in the pump casing of the pump section 300. The refrigerant flow path 115 is a flow path through which a refrigerant that cools the motor 200 flows. The refrigerant is, for example, oil. The refrigerant may be liquid or gas. The refrigerant flow path 115 is a space between the inner wall of the cylinder of the shaft section 111 and the impeller 130. The refrigerant flow path 115 is connected to refrigerant flow paths 116a and 117a extending radially inside the leg 112.

[0028] 7 is an enlarged plan cross-sectional view of the pump section 300 and its vicinity. The impeller 130 is a cascade impeller. The impeller 130 has a plurality of teeth 131 extending radially outward. The heat exchanger 110 has a partition 118 protruding into the refrigerant passage 115 at a circumferential position of the leg 112. The radially inner end of the partition 118 is located radially outward from the radially outer end of the teeth 131. The partition 118 is located, within the circumferential width of the leg 112, on the other circumferential side of the refrigerant passage 116a and on one circumferential side of the refrigerant passage 117a.

[0029] 8 is a side cross-sectional view of the drone 100 cut at the position of the coolant flow passage extending in the axial direction inside the leg 112. The leg 112 has coolant flow passages 116b and 117b extending in the axial direction. The radially outer end of the coolant flow passage 116a is connected to one axial end of the coolant flow passage 116b. The radially outer end of the coolant flow passage 117a is connected to one axial end of the coolant flow passage 117b.

[0030] The stator case 120 has refrigerant flow paths 121 and 122 extending in the axial direction. The other axial end of the refrigerant flow path 116b is connected to one axial end of the refrigerant flow path 121. The other axial end of the refrigerant flow path 117b is connected to one axial end of the refrigerant flow path 122.

[0031] FIG. 9 is a plan cross-sectional view showing the drone 100 cut at the position of a refrigerant flow path extending in the circumferential direction in a plane perpendicular to the axial direction in the stator case 120. The stator case 120 has a refrigerant flow path 123 extending in the circumferential direction in a plane perpendicular to the axial direction. The other axial end of the refrigerant flow path 121 is connected to the other circumferential end of the refrigerant flow path 123. The other axial end of the refrigerant flow path 122 is connected to one circumferential end of the refrigerant flow path 123. The stator case 120 has a separation portion 124 between the other circumferential end and the one circumferential end of the refrigerant flow path 123. Therefore, the refrigerant flow path 123 is not connected to go around the circumference in the circumferential direction.

[0032] Here, a description will be given of the flow of the coolant in the drone 100. The drone 100 has a closed flow path for circulating the coolant by coolant flow paths 115, 117a, 117b, 122, 123, 121, 116b, and 116a. The coolant is sealed in this closed circulation flow path.

[0033] When the drone 100 is driven, the rotor 150 rotates in one circumferential direction around the central axis J as a rotation axis. This rotation of the rotor 150 causes the rotor 151 to generate lift, causing the drone 100 to lift off. The rotation of the rotor 151 generates wind from one axial side to the other axial side of the drone 100. For this reason, the one axial side of the drone 100 may be referred to as the intake side, and the other axial side may be referred to as the exhaust side.

[0034] Rotation of rotor 150 in one circumferential direction rotates shaft 152 in one circumferential direction via rotor blades 151. Rotation of shaft 152 in one circumferential direction rotates impeller 130 fixed to one axial end of shaft 152 in one circumferential direction.

[0035] When the impeller 130 rotates in one circumferential direction, the pump unit 300 operates to suck the refrigerant in the refrigerant flow passage 116a into the refrigerant flow passage 115 and discharge the refrigerant in the refrigerant flow passage 115 into the refrigerant flow passage 117a. The refrigerant sent to the pump unit 300 flows through the refrigerant flow passage 123 in the stator case 120, thereby cooling the stator 180 housed in the stator case 120. That is, the refrigerant exchanges heat with the stator case 120, which has become heated by the heat of the stator 180, by flowing through the refrigerant flow passage 123 in the stator case 120. Thereafter, the refrigerant flows through the refrigerant flow passage 117a and returns to the refrigerant flow passage 115 to circulate.

[0036] The legs 112 of the heat exchanger 110 are cooled by receiving the wind generated by the rotation of the rotor 151. Since the legs 112 are provided on the intake side of the wind generated by the rotor 151, they are cooled more than when they are provided on the exhaust side. The refrigerant is cooled when it flows through the refrigerant flow paths 116a and 117a in the legs 112 that function as heat exchangers. That is, the refrigerant exchanges heat with the legs 112 that has been cooled by the wind generated by the rotation of the rotor 151 by flowing through the refrigerant flow paths 116a and 117a in the legs 112.

[0037] In this embodiment, the air guide members 101 and 102 are provided to guide the wind generated by the rotation of the rotor 151 toward the leg 112 .

[0038] The air guide member 101 is an example of a cylindrical member that covers at least the radial outside of the leg portion 112 as a heat exchanger. As shown in FIG. 1, the air guide member 101 is a cylindrical member with an outer diameter size that is approximately equal to the outer diameter size of the stator case 120. The axial length of the air guide member 101 is longer than the length from the surface on one axial side of the stator case 120 to the surface on one axial side of the leg portion 112. If the air guide member 101 is not provided, the intake air from the outside to the rotor 151 may reach the rotor 151 through the other axial side of the leg portion 112 having the refrigerant flow paths 116a and 117a. In this case, the amount of air flowing toward the leg portion 112 is small, and the leg portion 112 cannot be cooled efficiently. If the air guide member 101 is provided, the intake air to the rotor 151 can be guided toward the leg portion 112 without passing through the other axial side of the leg portion 112, and the leg portion 112 can be cooled more efficiently.

[0039] The air guide member 102 is an example of a member that blocks at least a part of a portion of the leg 112 as a heat exchanger, other than a portion facing the leg 112 in the axial direction. As shown in Figs. 1 and 5, the air guide member 102 has a wind shielding surface that spreads in a sector shape in a direction perpendicular to the axial direction between the leg 113 and the leg 114. As shown in Fig. 6, the air guide member 102 has a wind shielding surface that spreads in the axial direction from a radially outer end of the wind shielding surface that spreads in a direction perpendicular to the axial direction to a surface on one axial side of the stator case 120. By providing the air guide member 102, the intake air from the outside to the rotor 151 can be guided toward the leg 112 without passing between the leg 113 and the leg 114, and the leg 112 can be cooled more efficiently.

[0040] According to this embodiment, the flow of the refrigerant can be generated by the impeller 130 rotating together with the rotor 150, and there is no need to provide an external power source for the pump section 300, making it possible to realize a compact and lightweight drone 100.

[0041] Furthermore, according to this embodiment, by providing a heat exchanger that uses the wind generated by the rotor 151 that drives the drone 100 for cooling, a more efficient cooling structure for the motor of the drone can be provided.

[0042] The present invention is not limited to the above-mentioned embodiment, and various improvements and design changes may be made without departing from the spirit of the present invention. In addition, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0043] 100: drone, 110: heat exchanger, 120: stator case, 150: rotor, 151: rotor blade, 152: shaft, 180: stator, 200: motor

Claims

1. A stator; a rotor facing the stator across a gap; a stator case that houses the stator; a heat exchanger disposed on one axial side of the stator case; A rotor blade that rotates due to rotation of the rotor; having The stator case has a refrigerant flow passage extending in a circumferential direction and through which a refrigerant flows, The heat exchanger includes a heat exchange portion that performs heat exchange of a refrigerant, and a pump portion that generates a flow that circulates the refrigerant between the refrigerant flow path and the heat exchange portion, The heat exchange unit exchanges heat between the wind generated by the rotation of the rotor blades and the refrigerant. A drone characterized by

2. The heat exchanger is disposed on the intake side of the rotor. The drone according to claim 1 .

3. The pump unit is driven by rotation of the rotor. The drone according to claim 1 .

4. The rotor blades are integral with the rotor. The drone according to claim 1 .

5. The rotor includes a wind guide section that guides wind generated by the rotation of the rotor to the heat exchange section. The drone according to claim 1 .

6. The airflow guidance section is a cylindrical member that covers at least the radially outer side of the heat exchange section. The drone according to claim 5 .

7. The airflow guidance section is on one axial side of the heat exchange section and closes at least a portion of a portion other than a portion facing the heat exchange section in the axial direction. The drone according to claim 5 .

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