Motor

Abstract

To provide a motor capable of suppressing heat evolution.SOLUTION: A motor (1) has a rotor (15), a stator (13) facing the rotor (15), bearings (19a, 19b) rotatably supporting the rotor (15), a blade (2) attached on one side in an axial (X) direction of the rotor (15), and a holding part (11) holding the bearings (19a, 19b). The holding part (11) has an attaching part (112) to which an external device (3) is attached, and a contact part (113) contacting the stator (13). An end face (112a) on one side in the axial (X) direction of the attaching part (112) is arranged on the other side in the axial (X) direction compared with an end face (113b) on the other side in the axial (X) direction of the contact part (113).SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] A motor is known in which an opening is formed in a base portion, and the wind generated by the rotation of the propeller passes through the opening in the base portion, thereby cooling the motor (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-68604 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there has been a demand for improving the cooling efficiency of the motor and suppressing heat generation from the motor.

[0005] The present invention has been made in view of the above background, and provides a motor that can suppress heat generation. [Means for solving the problem]

[0006] The above-mentioned problems are solved by the present invention, which provides a motor including a rotor, a stator facing the rotor, a bearing that rotatably supports the rotor, blades attached to one axial side of the rotor, and a holding part that holds the bearing, the holding part having an attachment part to which an external device is attached and a contact part that comes into contact with the stator, and an end face on the one axial side of the attachment part being positioned on the other axial side of an end face on the other axial side of the contact part. [Brief explanation of the drawings]

[0007] [Figure 1]1 is a perspective view from above showing the overall configuration of an outer rotor type motor according to one embodiment of the present invention; [Figure 2] 1 is a perspective view from below showing the overall configuration of an outer rotor type motor according to an embodiment of the present invention; [Figure 3] 1 is a perspective cross-sectional view of a motor according to an embodiment of the present invention; [Figure 4] 1 is a cross-sectional view of a motor according to an embodiment of the present invention. [Figure 5] 1 is a perspective view showing a configuration of a holder of a motor according to an embodiment of the present invention; [Figure 6] 1 is a cross-sectional view showing a configuration of a holder of a motor according to an embodiment of the present invention. [Figure 7] 1 is a perspective view showing a configuration of a stator core of a motor according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0008] Embodiments of the present invention will be described with reference to the drawings. Fig. 1 is a perspective view from above showing the overall configuration of an outer rotor type motor according to one embodiment of the present invention. Fig. 2 is a perspective view from below showing the overall configuration of an outer rotor type motor according to one embodiment of the present invention. Fig. 3 is a perspective cross-sectional view of a motor according to one embodiment of the present invention. Fig. 4 is a cross-sectional view of a motor according to one embodiment of the present invention. Fig. 5 is a perspective view showing the configuration of a holder of a motor according to one embodiment of the present invention. Fig. 6 is a cross-sectional view showing the configuration of a holder of a motor according to one embodiment of the present invention. Fig. 7 is a perspective view showing the configuration of a stator core of a motor according to one embodiment of the present invention.

[0009] In the following description of this embodiment, for convenience, the direction in which axis X extends when motor 1 rotates will be referred to as the axial direction (rotation axis direction). Also, for convenience, in the following description, the direction of arrow a in the axial direction will be referred to as the upper side or upward, and the direction of arrow b will be referred to as the lower side or downward. In the radial direction perpendicular to axis X, the direction of arrow c, which moves away from axis X, will be referred to as the outer circumferential side or outward, and the direction of arrow d, which moves closer to axis X, will be referred to as the inner circumferential side or inward. In the circumferential direction of motor 1 as viewed from above, the direction of arrow e will be referred to as the clockwise direction, and the direction of arrow f will be referred to as the counterclockwise direction. In the following description, the upper side (the direction of arrow a) and the lower side (the direction of arrow b) refer to the vertical relationship of motor 1 on the drawing, and do not necessarily coincide with the vertical relationship in the direction of gravity.

[0010] As shown in FIGS. 1 to 7, motor 1 is an outer rotor brushless motor mounted on a floating mobile body such as a drone (not shown). 1 to 4, motor 1 has drone propellers (blades) 2 (see FIG. 4) attached to rotor housing 17 on the upper side (in the direction of arrow a), and drone body (external device) 3 attached to holder 11 on the lower side (in the direction of arrow b). As shown in FIGS. 3 and 4, motor 1 mainly has holder 11, stator 13, rotor 15, rotor housing 17, heat sink 18, and bearing 19.

[0011] The holder 11 is made of a non-magnetic material such as aluminum, and is a member that holds the stator 13 and the bearings 19. That is, the holder 11 functions as a holding portion. As shown in FIGS. 3 to 6, the holder 11 is a cylindrical member that is formed into a circular shape in a plan view. The holder 11 has an inner wall portion (first wall portion) 111, an attachment portion 112, an outer wall portion (second wall portion) 113, and a connection portion 114.

[0012] The inner wall portion 111 is formed on the inner circumferential side (direction of arrow d) in the radial direction of the holder 11. The inner wall portion 111 extends in the direction of the axis X and is formed into a cylindrical or approximately cylindrical shape overall. The inner wall portion 111 holds two bearings 19 (19a, 19b) on a surface 111n on the inner circumferential side (direction of arrow d) (hereinafter referred to as the "inner circumferential surface"). The two bearings 19 (19a, 19b) rotatably hold the rotor 15. The two bearings 19 (19a, 19b) are fitted into the inner peripheral surface 111n of the inner wall portion 111 and fixed to the inner wall portion 111 with an adhesive or the like. Note that the means for fixing the two bearings 19 is not limited to fitting and adhesive, and the outer ring of the bearing 19 may be press-fitted into the inner peripheral surface 111n of the inner wall portion 111 to fix them. That is, the inner wall portion 111 functions as a bearing holder (bearing holding portion) that holds the two bearings 19. The bearings 19 are, for example, ball bearings. However, the bearings 19 are not limited to ball bearings, and various other bearings such as sleeve bearings may also be used. The inner diameter of the lower end (in the direction of arrow b) of the inner circumferential surface 111n of the inner wall portion 111 is larger than that of the other portions, and a female screw groove 111s is formed therein.

[0013] A pusher 12 formed in a thin disk shape is fixed to the end (lower side (direction of arrow b)) of the inner wall portion 111 of the holder 11 opposite to the rotor housing 17. The pusher 12 has the function of applying a preload to the bearing 19. The pusher 12 has a radially outer surface (in the direction of arrow c) (hereinafter referred to as the "outer surface") that is screwed into the inner peripheral surface 111n of the inner wall portion 111 and fixed to the inner wall portion 111 with an adhesive or the like. For example, a screw groove (external screw groove) 12s is formed on the radially outer surface (in the direction of arrow c) of the pusher 12, and the screw groove 12s is screwed into an internal screw groove 111s formed on the inner peripheral surface 111n of the inner wall portion 111. The pusher 12 has a step portion 12a at its radially outer end. The step portion 12a supports the bearing 19a from below (in the direction of arrow b).

[0014] The mounting portion 112 is a portion to which the drone's airframe (external device) 3 is attached. The mounting portion 112 is provided at the lower end (in the direction of arrow b) of the inner wall portion 111. The mounting portion 112 is formed continuously with the inner wall portion 111 and is integrally formed therewith. More specifically, the mounting portion 112 is a portion of the inner wall portion 111 whose lower end (in the direction of arrow b) has an outer diameter that expands toward the outer periphery (in the direction of arrow c). As shown in FIGS. 5 and 6 , the mounting portion 112 is formed in an annular shape when viewed from above. The mounting portion 112 has a plurality of holes 112h formed along the axis X. The holes 112h are holes through which fasteners and wiring used when attaching the airframe 3, as well as wind generated by the propeller 2, etc., pass. The mounting portion 112 is formed to a size such that the surface facing the airframe 3 is covered by the airframe 3. The mounting portion 112 is formed to have a predetermined height. Specifically, the attachment portion 112 is formed to extend in the X-axis direction.

[0015] The outer wall portion 113 is formed on the outer peripheral side (direction of arrow c) in the radial direction of the holder 11. The outer wall portion 113 extends in the axial X direction and is formed into a cylindrical or approximately cylindrical shape overall. The outer wall portion 113 is formed continuously with the connecting portion 114 and is formed integrally with the connecting portion 114. The outer wall portion 113 holds the stator 13 at a surface 113g on the outer peripheral side (direction of arrow c) (hereinafter referred to as the "outer peripheral surface"). Note that the connecting portion 114 may be formed separately from the outer wall portion 113 and the mounting portion 112 and may be formed integrally with the outer wall portion 113 and the mounting portion 112 using a fastening member or the like. The stator 13 is fitted into the outer peripheral surface 113g of the outer wall portion 113 and fixed to the outer wall portion 113 with an adhesive or the like. Note that the means for fixing the stator 13 is not limited to fitting and adhesive, and the stator 13 may be fixed by press-fitting into the outer peripheral surface 113g of the outer wall portion 113. In other words, the outer wall portion 113 functions as a contact portion that comes into contact with the stator 13. The outer diameter of the outer wall portion 113 (outer peripheral surface 113g) is approximately the same as the inner diameter of an inner peripheral surface 132n (FIG. 7) of an annular portion 132 of the stator core 131, which will be described later. However, this is not limiting, and the outer diameter of the outer wall portion 113 (outer peripheral surface 113g) may be slightly smaller or slightly larger than the inner diameter of the inner peripheral surface 132n of the annular portion 132. The outer wall portion 113 has a function of holding the stator core 131, and the outer wall portion 113 forms a stator holding portion. The outer wall portion 113 is provided at a predetermined interval on the outer circumferential side (in the direction of the arrow c) from the inner wall portion 111. The outer wall portion 113, like the inner wall portion 111, extends along the direction of the axis X.

[0016] An end face 113b of outer wall portion 113 on the lower side in the axial X direction (direction of arrow b) is disposed higher in the axial X direction (direction of arrow a) than an end face 112a of mounting portion 112 on the upper side in the axial X direction (direction of arrow a). In other words, end face 112a of mounting portion 112 on one side in the axial X direction (direction of arrow a) is disposed higher in the axial X direction (direction of arrow b) than end face 113b of outer wall portion 113 on the other side in the axial X direction (direction of arrow b). Therefore, a space is formed along the axial X direction between end face 112a of mounting portion 112 on the upper side in the axial X direction (direction of arrow a) and end face 113b of outer wall portion 113 on the lower side in the axial X direction (direction of arrow b). The outer wall portion 113 is formed so that both its outer diameter and inner diameter are larger than those of the inner wall portion 111 and the mounting portion 112. Specifically, the inner diameter of the outer wall portion 113 is formed so that it is larger than those of the inner wall portion 111 and the mounting portion 112. When the holder 11 is viewed from above, a space is formed between an outer peripheral surface 111g of the inner wall portion 111 and an outer peripheral surface 112g of the mounting portion 112 and an inner peripheral surface 113n of the outer wall portion 113. When stator 13 is attached to holder 11, end face 113b of outer wall portion 113 on the lower side in the axial X direction (direction of arrow b) is disposed above end face 139b of coil 139 on the lower side in the axial X direction (direction of arrow b). In other words, end face 139b of coil 139 on the other side in the axial X direction (direction of arrow b) is disposed above end face 113b of outer wall portion 113 on the other side in the axial X direction (direction of arrow b).

[0017] The connecting portion 114 is formed to extend from near an upper end (in the direction of arrow a) of the outer peripheral surface 112g of the mounting portion 112 in the axial X direction toward near an lower end (in the direction of arrow b) of the inner peripheral surface 113n of the outer wall portion 113 in the axial X direction. In other words, the connecting portion 114 is a portion that connects the mounting portion 112 and the outer wall portion 113 and extends at an inclination radially inward from the axial X direction. Specifically, the connecting portion 114 intersects with the extension direction (in the direction of arrow X) of the mounting portion 112 and the outer wall portion 113 and extends obliquely so as to approach the inner peripheral side (in the direction of arrow d) as it moves downward in the axial X direction (in the direction of arrow b). Therefore, as shown in FIG. 5 , a step is formed in the axial X direction between the end face 112b of the mounting portion 112 on the lower side (in the direction of arrow b) in the axial X direction and the end face 113b of the outer wall portion 113 on the lower side (in the direction of arrow b) in the axial X direction. One end (the end on the lower side (in the direction of arrow b)) of connecting portion 114 is formed continuous with mounting portion 112, and is formed integrally with mounting portion 112. The other end (the end on the upper side (in the direction of arrow a)) of connecting portion 114 is formed continuous with outer wall portion 113, and is formed integrally with outer wall portion 113. A plurality of connection portions 114 are provided at predetermined intervals along the circumferential direction of the attachment portion 112 and the outer wall portion 113. Therefore, an opening S is formed between adjacent connection portions 114.

[0018] A heat sink (cooling portion) 18 is provided between the inner wall portion 111 and the outer wall portion 113. The heat sink 18 is provided at a position facing the stator 13 in the radial direction. The heat sink 18 is formed in a plate shape and has a function of dissipating heat from within the motor 1. The heat sink 18 is provided at a position facing the stator 13 in the radial direction with the outer wall portion 113 interposed therebetween. The length of the heat sink 18 along the axial direction is shorter at its outer peripheral portion than at its outer wall portion 113, but longer at its inner peripheral portion than at its outer wall portion 113. Here, the inner peripheral portion of the heat sink 18 refers to the portion facing the mounting portion 112 along the axial direction. In other words, a part of the heat sink 18 has a protruding portion 18b that protrudes downward along the axial direction (in the direction of arrow b), and the protruding portion 18b faces the mounting portion 112. A plurality of heat sinks 18 are provided at predetermined intervals along the circumferential direction of the inner wall portion 111 and the outer wall portion 113. Therefore, a space is formed between adjacent heat sinks 18. The shape of the heat sink 18 may be a rectangle in which the lengths of the outer peripheral portion and the inner peripheral portion are equal, or the outer peripheral portion may be shorter than the inner peripheral portion. Any shape may be used as long as it comes into contact with the wind W passing through the inside of the motor 1.

[0019] The stator 13 is fixed to an outer peripheral surface 113g of the outer wall portion 113 of the holder 11. As shown in FIGS. 3 and 4, the stator 13 is provided at a position facing the rotor 15. The stator 13 has a stator core 131 and a coil 139. As shown in FIG. 7, stator core 131 is a laminated body of magnetic materials such as silicon steel plates. Stator core 131 has an annular portion 132, teeth 133, and tip portions 134. Teeth 133 and tip portions 134 are collectively referred to as a magnetic pole portion.

[0020] The annular portion 132 is an annular body formed in a circular shape in a plan view, and is formed to have a predetermined thickness in the radial direction. The inner surface 132n of the annular portion 132 (the side end surface on the inner diameter side in the radial direction of the stator 13) is the part that contacts the outer peripheral surface 113g of the outer wall portion 113 of the holder 11, and the outer peripheral surface 132g of the annular portion 132 is the part where the tooth portion 133 is formed.

[0021] The teeth 133 are formed on an outer peripheral surface 132g of the annular portion 132. The teeth 133 are formed integrally with the annular portion 132 so as to extend from the outer peripheral surface 132g of the annular portion 132 toward the outer periphery (the side in the direction of arrow c). In other words, the teeth 133 are formed so as to extend along the radial direction of the annular portion 132. A plurality of teeth 133 are formed at regular intervals along the circumferential direction of the outer peripheral surface 132g of the annular portion 132.

[0022] The tip portions 134 are formed at the tip of each tooth portion 133. The tip portions 134 are formed integrally with the tooth portions 133 so as to protrude from the tip of the tooth portion 133 in the clockwise direction (the direction of arrow e) and the counterclockwise direction (the direction of arrow f) in the circumferential direction of the annular portion 132. The tip portions 134 are formed with a fixed gap between them so that adjacent tip portions 134 do not come into contact with each other. The gap between adjacent tip portions 134 is narrower than the gap (slot) between adjacent tooth portions 133.

[0023] Insulators 138 (see FIG. 4) made of an insulating material are attached to the annular portion 132 and the tooth portions 133 of the stator core 131, and coils 139 are wound around the insulators 138. That is, the annular portion 132 and the tooth portions 133 of the stator core 131 are electrically insulated from the coils 139 via the insulators 138. Note that an insulating resin film may be applied or formed on the surface of the stator core 131, and the resin film may be used as an insulator.

[0024] 3 and 4, the rotor 15 is formed in an annular shape. The rotor 15 includes a yoke 151 and a magnet 153.

[0025] The yoke 151 is an iron core having a cylindrical shape extending along the axis X. The yoke 151 surrounds the magnet 153 and holds the magnet 153 together. The yoke 151 forms a magnetic circuit together with the magnet 153 and is made of a magnetic material such as iron. The yoke 151 is formed higher than the magnet 153 in the direction of the axis X.

[0026] The magnet 153 is an integrally molded magnetic body. The magnet 153 has a cylindrical shape extending along the axis X, similar to the yoke 151. The magnet 153 is fixed to the inner circumferential surface 151n of the yoke 151 using an adhesive. However, the method is not limited to an adhesive, and the magnet 153 may be held in contact with the inner circumferential surface 151n of the yoke 151 by press-fitting or the like, for example. The inner circumferential surface of magnet 153, which faces tip end 134 of stator core 131, is divided into an area magnetized to an S pole and an area magnetized to an N pole, which are arranged alternately along the circumferential direction. The height of magnet 153 in the axial X direction is formed to be lower than the height of yoke 151 in the axial X direction. Note that the height of magnet 153 in the axial X direction may be formed to be equal to the height of yoke 151 in the axial X direction. That is, the magnet 153 is held in a state in which the outer peripheral surface 153g of the magnet 153 is covered from the outer peripheral side (the side in the direction of the arrow c) by the yoke 151. An outer peripheral portion 173 (described later) of the rotor housing 17 is held by an inner peripheral surface 151n of the yoke 151 and an end face 153a on the upper side (the direction of the arrow a) of the magnet 153.

[0027] The rotor housing 17 is made of a relatively light metal such as an aluminum alloy and has an overall disk shape. However, the material of the rotor housing 17 is not limited to an aluminum alloy, and the rotor housing 17 may be made of other materials such as resin or plastic. As shown in FIGS. 1, 3, and 4, the rotor housing 17 has an inner circumferential portion 171, an outer circumferential portion 173, and spoke portions 175.

[0028] 3 and 4, the inner peripheral portion 171 is formed on the inner peripheral side (direction of arrow c) of the rotor housing 17. The inner peripheral portion 171 is formed in a disk shape, and has a hole 171h formed in the center about the axis X. The inner peripheral portion 171 has an outer diameter that allows it to cover the inner wall portion 111 of the holder 11 from above (direction of arrow a). The inner peripheral portion 171 has a cylindrical rotating shaft 172 that extends in the vertical direction (the direction of the arrow ab) around the axis X. The inner ring of the bearing 19 (19a, 19b) is held on an outer peripheral surface 172g of the rotating shaft 172. That is, the rotating shaft 172 rotates together with the rotor 15 in the motor 1. Note that the rotating shaft 172 may have a cylindrical shape with no space on the inner peripheral side. The propeller 2 is attached to the rotary shaft 172 by a bolt 2b. That is, the propeller 2 rotates together with the rotary shaft 172 in the motor 1.

[0029] The outer peripheral portion 173 is formed in an annular shape at the end portion on the outer peripheral side (direction of arrow c) of the rotor housing 17. The outer peripheral portion 173 is a portion that covers the magnet 153 fixed to the inner peripheral surface 151n of the yoke 151 from above (direction of arrow a) with its end portion on the outer peripheral side (direction of arrow c) in the radial direction. The outer peripheral portion 173 is press-fitted into the inner peripheral surface 151n of the yoke 151, thereby being attached integrally to the yoke 151, and an outer surface 173m of the outer peripheral portion 173 is in contact with the inner peripheral surface 151n of the yoke 151. The outer peripheral portion 173 may also be attached integrally to the yoke 151 by adhesively bonding the inner peripheral surface 151n of the yoke 151.

[0030] A plurality of spokes 175 (for example, six) are formed and connect the inner circumferential portion 171 and the outer circumferential portion 173. One end of each spoke 175 is connected to the edge of the inner circumferential portion 171 on the outer circumferential side (direction of arrow c), and the other end is connected to the edge of the outer circumferential portion 173 on the inner circumferential side (direction of arrow d). The inner peripheral portion 171, the outer peripheral portion 173, and the spoke portions 175 are integrally formed.

[0031] In the above configuration, the holder 11 is inserted into the stator core 131 so that the inner peripheral surface 132n of the annular portion 132 of the stator core 131 is aligned with the outer peripheral surface 113g of the outer wall portion 113 of the holder 11. At this time, adhesive is applied in advance to the outer peripheral surface 113g of the outer wall portion 113 of the holder 11. When the holder 11 is inserted into the stator core 131, the outer peripheral surface 113g of the outer wall portion 113 of the holder 11 and the inner peripheral surface 132n of the annular portion 132 of the stator core 131 are brought into close contact with each other, and the adhesive is allowed to dry, thereby fixing the stator core 131 to the holder 11. In addition, the pusher 12 , the bearing 19 , and the rotor housing 17 are attached to the inner wall portion 111 of the holder 11 . In this way, the motor 1 can be assembled.

[0032] According to the above configuration, when motor 1 is driven, propeller 2 attached to rotor 15 also rotates around axis X together with rotation shaft 172. Wind W (see FIG. 6) generated by the rotation of propeller 2 flows toward the lower side of motor 1 (in the direction of arrow b). At this time, wind W attempts to pass through opening S between mounting portion 112 and outer wall portion 113 to the lower side of motor 1 (in the direction of arrow b). Here, end face 112a of mounting portion 112 on the upper side in the direction of axis X (in the direction of arrow a) is located lower in the direction of axis X (in the direction of arrow b) than end face 113b of outer wall portion 113 on the lower side in the direction of axis X (in the direction of arrow b). Therefore, as shown by the arrow in FIG. 6, the flow of wind W inside motor 1 attempts to exit through opening S before hitting mounting portion 112. That is, the wind W reaches the opening S before the end face 112a of the mounting portion 112 on the upper side in the axial X direction (in the direction of the arrow a), so that the wind W can easily pass from the upper side to the lower side of the motor 1 to avoid collision with the body 3, ensuring a sufficient flow velocity and volume. This prevents the wind W from accumulating inside the motor 1, thereby improving the cooling efficiency of the motor 1 and suppressing heat generation by the motor 1. It also improves the efficiency of the motor 1. It also reduces the risk of burning out the coil 139 and improves the cooling performance of the heat sink 18.

[0033] Furthermore, because the connecting portion 114 is disposed at an angle radially inward relative to the axial X direction, a step can be formed in the axial X direction between the mounting portion 112 and the outer wall portion 113, as shown in Fig. 5, and this step can be used as the opening S. Furthermore, because the outer wall portion 113 is formed outward of the mounting portion 112, a space can be formed between the outer peripheral surface 112g of the mounting portion 112 and the inner peripheral surface 113n of the outer wall portion 113, and a path for the wind W can be secured even when the machine body 3 covers the entire mounting portion 112. Therefore, the cooling of the motor 1 by the wind W is less affected by the size of the machine body 3. Furthermore, since the connection portions 114 are arranged at intervals along the circumferential direction of the attachment portion 112 and the outer wall portion 113, many paths for the wind W to pass through can be formed. Furthermore, end face 139b of coil 139 on the other side in the axial X direction (direction of arrow b) is positioned closer to the other side in the axial X direction (direction of arrow b) than end face 113b of outer wall portion 113 on the other side in the axial X direction (direction of arrow b). This makes it easier for wind W passing through opening S to hit coil 139, thereby improving the cooling efficiency of coil 139. Furthermore, since the heat sink 18 faces the stator 13 in the radial direction and faces the mounting portion 112 of the holder 11 in the axial X direction, the heat sink 18 is positioned in the path of the wind W, and the heat of the heat sink 18 can be efficiently dissipated to the outside by the wind W. Furthermore, since the heat sink 18 faces the stator 13 via the outer wall portion 113, the heat of the stator 13 can be easily absorbed. Furthermore, the heat sink 18 has a protruding portion 18b that protrudes in the axial direction X, and the protruding portion 18b faces the mounting portion 112 of the holder 11 in the axial direction X, so that the heat sink 18 can be made as large as possible, thereby improving the cooling efficiency of the motor 1.

[0034] <Other forms> Although the motor has been described above by citing preferred embodiments, the motor is not limited to the configuration of the above embodiments. For example, the motor 1 described above is configured as an outer rotor brushless motor, but the present invention is also applicable to motors other than brushless motors, such as inner rotor motors. Furthermore, the outer peripheral surface 112g of the mounting portion 112 may be an inclined surface that slopes radially inward (in the direction of arrow d) as it moves upward in the direction of axis X (in the direction of arrow a). This allows the opening S between the mounting portion 112 and the outer wall portion 113 to be larger, improving the cooling efficiency of the motor 1 and suppressing heat generation by the motor 1. Furthermore, the inner peripheral surface 113n of the outer wall portion 113 may be an inclined surface that slopes radially outward (in the direction of arrow c) as it approaches downward in the direction of axis X (in the direction of arrow b). This allows the opening S between the mounting portion 112 and the outer wall portion 113 to be larger, improving the cooling efficiency of the motor 1 and suppressing heat generation by the motor 1. Furthermore, the inner wall portion 111, the attachment portion 112, the outer wall portion 113, and the connection portion 114 that constitute the holder 11 may be formed integrally, or some of them may be formed separately. Also, a disc-shaped rotor housing without spokes 175 may be used. In addition, those skilled in the art can appropriately modify the motor of the present invention in accordance with conventionally known knowledge. As long as such modifications still comprise the configuration of the present invention, they are of course included in the scope of the present invention. [Explanation of symbols]

[0035] 1...motor, 2...propeller, 3...airframe, 11...holder, 12...pusher, 13...stator, 15...rotor, 17...rotor housing, 18...heat sink, 19 (19a, 19b)...bearing, 111...inner wall portion, 112...mounting portion, 113...outer wall portion, 114...connecting portion, 131...stator core, 132...annular portion, 133...teeth portion, 134...tip portion, 138...insulator, 139...coil, 151...yoke, 153...magnet, 171...inner periphery, 173...outer periphery, 175...spoke portion.

Claims

1. A rotor, a stator facing the rotor; a bearing that rotatably supports the rotor; a blade attached to one axial side of the rotor; a holding portion that holds the bearing, the holding portion has an inner wall portion that holds the bearing, an attachment portion to which an external device is attached, an outer wall portion that holds the stator, a contact portion that comes into contact with the stator, and a plurality of connection portions that connect the attachment portion and the outer wall portion, The attachment portion is provided on the inner wall portion, an end face on one axial side of the attachment portion is disposed on the other axial side of an end face on the other axial side of the contact portion, The plurality of connection portions are arranged to be inclined radially inward from the axial direction, An opening is formed between two adjacent connection portions among the plurality of connection portions. Motor.

2. the stator has a coil; an end surface of the coil on the other axial side is disposed on the other axial side of the end surface of the contact portion on the other axial side; The motor according to claim 1 .

3. the heat sink faces the stator in the radial direction via the holding portion; 3. The motor according to claim 1 or 2.

4. the heat sink faces the mounting portion and the connecting portion in the axial direction; The motor according to claim 3 .

5. The heat sink has a protrusion that protrudes in an axial direction, The protruding portion faces the mounting portion in the axial direction.

5. The motor according to claim 3 or 4.

6. The heat sink is disposed between the inner wall portion and the outer wall portion.

5. The motor according to claim 3 or 4.

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