motor

Abstract

To provide a motor having further improved stability of supporting force of a stator.SOLUTION: A motor (1) includes: a rotating shaft (10); blades (11a and 11b) provided on the rotating shaft (10); a holder (30) having cylindrical members (31 and 33); a rotor (20); and a stator (40) opposite to the rotor (20) in a radial direction of the rotor (20), wherein the stator (40) is fixed to the cylindrical members (31 and 33), the stator (40) includes a magnetic body (401), a coil (406), and a resin member (410), a part of the resin member (410) intrudes between windings of the coil (406), other part of the resin member (410) forms the side face of the stator (40), and other part of the resin member (410) faces the blades (11a and 11b) in the axial direction of the rotating shaft (10).SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Conventionally, drone motors have a propeller attached to the top of the motor, and the wind generated by the propeller is used to cool the motor body and the interior of the motor. Motors used in drones are classified into outer rotor and inner rotor types.

[0003] For example, as an inner rotor type motor, a brushless motor has been proposed in which a thermally conductive heat transfer material is arranged between the coil winding surface of the stator located inside the motor case and the end face and inner surface of the case, thereby ensuring a heat conduction path from the coil to the case (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-98862 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the brushless motor of Patent Document 1, the stator and rotor are entirely covered by a case, so heat dissipation is not sufficient, and there are cases where it is desired to improve the efficiency of the motor.

[0006] An example of an object of the present invention is to provide a motor with improved heat dissipation properties. [Means for solving the problem]

[0007] The above-mentioned problems are solved by the present invention, which provides a motor including a rotating shaft, blades provided on the rotating shaft, a holder having a cylindrical member, a rotor, and a stator facing the rotor in a radial direction of the rotor, the stator being fixed to the cylindrical member, the stator including a magnetic body, a coil, and a resin member, a portion of the resin member being inserted between windings of the coil, another portion of the resin member forming a side surface of the stator, and another portion of the resin member facing the blades in an axial direction of the rotating shaft. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing the overall configuration of an outer rotor type motor used in a drone according to an embodiment of the present invention. FIG. [Figure 2] 1 is a perspective cross-sectional view showing a state in which a drone propeller is removed from a motor according to an embodiment of the present invention. FIG. [Figure 3] 1 is a perspective cross-sectional view showing the internal structure of a motor according to an embodiment of the present invention. [Figure 4] 1 is a perspective view showing a configuration of a holder according to an embodiment of the present invention; [Figure 5] 1 is a perspective view showing a configuration of a stator core according to an embodiment of the present invention; [Figure 6] 1 is a perspective view showing the arrangement of a stator core, an insulator, a coil, a yoke, and a magnet according to an embodiment of the present invention. FIG. [Figure 7] 1 is a perspective cross-sectional view showing a closed space formed inside a motor according to an embodiment of the present invention; [Figure 8] 1 is a perspective view showing a configuration of a heat sink according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0009] <Embodiments of the present invention> Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing the overall configuration of an outer rotor type motor used in a drone according to one embodiment of the present invention. FIG. 2 is a perspective cross-sectional view showing a state in which the drone's propellers have been removed from the motor according to one embodiment of the present invention. FIG. 3 is a perspective cross-sectional view showing the internal structure of a motor according to one embodiment of the present invention. FIG. 4 is a perspective view showing the configuration of a holder according to one embodiment of the present invention. FIG. 5 is a perspective view showing the configuration of a stator core according to one embodiment of the present invention. FIG. 6 is a perspective view showing the arrangement of a stator core, insulators, coils, yokes, and magnets according to one embodiment of the present invention. FIG. 7 is a perspective cross-sectional view showing a closed space formed inside a motor according to one embodiment of the present invention. FIG. 8 is a perspective view showing the configuration of a heat sink according to one embodiment of the present invention.

[0010] 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 or rotational 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 away from axis X will be referred to as the outer circumferential side or outer side, and the direction of arrow d approaching axis X will be referred to as the inner circumferential side or inner side. In the circumferential direction of motor 1, the direction of arrow e in a top view will be referred to as the clockwise direction, and the direction of arrow f will be referred to as the counterclockwise direction.

[0011] 1 to 5, motor 1 is an inner rotor brushless motor mounted on a floating mobile body such as a drone (not shown). As shown in Figures 1 to 3, motor 1 includes a rotating shaft 10, a propeller 11 fixed to rotating shaft 10, a rotor 20, a holder 30 that supports a bearing, and a stator 40 that faces rotor 20. Motor 1 is a so-called inner rotor type in which rotor 20, which is provided inside stator 40, i.e., on the rotating shaft 10 side, rotates, and rotating shaft 10 rotates together with rotor 20.

[0012] The motor 1 has a propeller 11 attached to a rotating shaft 10 that protrudes upward (in the direction of arrow a), and the propeller 11 rotates integrally with the rotating shaft 10. The propeller 11 has a plurality of blades (for example, two blades) 11a and 11b centered on a connecting portion 11c.

[0013] The rotating shaft 10 is formed of a cylindrical member and protrudes upward by a predetermined distance from the upper bearing 53. The rotating shaft 10 has a through-hole 10h, and the shaft (not shown) of the connecting portion 11c of the propeller 11 is press-fitted or glued into the through-hole 10h to be attached integrally.

[0014] The rotating shaft 10 is rotatably supported by a bearing 51 arranged on the lower side and a bearing 53 arranged on the upper side. The bearings 51, 53 are fixed in the radial direction by press-fitting inner rings 51n, 53n of the bearings 51, 53 onto the outer peripheral surface 10g of the rotating shaft 10 (hereinafter referred to as the "outer peripheral surface") 10g. If necessary, the bearings 51, 53 may be fixed integrally with the rotating shaft 10 using an adhesive or the like while fitted onto the rotating shaft 10.

[0015] The bearings 51 and 53 are, for example, ball bearings. However, the bearings 51 and 53 are not limited to these, and various other bearings such as sleeve bearings may also be used. The bearings 51 and 53 are provided in and supported by a holder 30, which will be described later.

[0016] In the motor 1, a rotor 20 is fixed to an outer peripheral surface 10g of a rotating shaft 10. The rotor 20 is composed of a yoke 21 and a magnet Mg.

[0017] The yoke 21 is an annular member extending vertically along the axis X, and is fitted onto the outer peripheral surface 10g of the rotating shaft 10. The yoke 21 has an inner cylindrical portion (hereinafter referred to as the "inner cylindrical portion") 211 arranged on the rotor 20 side in the radial direction, an outer cylindrical portion (hereinafter referred to as the "outer cylindrical portion") 212 arranged on the stator 40 side in the radial direction, and an annular connecting portion 213 connecting the inner cylindrical portion 211 and the outer cylindrical portion 212 in the radial direction.

[0018] A magnet Mg is attached integrally to the outer peripheral surface 212g of the outer cylindrical portion 212 of the yoke 21 by adhesive or the like. The outer cylindrical portion 212 of the yoke 21 and the magnet Mg have the same thickness in the axial direction. The yoke 21 is an iron core made of a magnetic material such as iron.

[0019] The magnet Mg is an integrally molded magnetic body, and is divided into an area magnetized to the south pole and an area magnetized to the north pole, which are arranged alternately in the circumferential direction. The magnet Mg is fixed to the outer peripheral surface 212g of the yoke 21 by adhesive or the like, but this is not limiting and the magnet Mg may be fixed by press-fitting or the like.

[0020] Holder 30 supports bearing 51 arranged on the lower side and bearing 53 arranged on the upper side, and is a member made of a metal material such as an aluminum alloy. Holder 30 is formed by a cylindrical member 31 arranged on the lower side (hereinafter referred to as the "lower cylindrical member") and a cylindrical member 33 arranged on the upper side (hereinafter referred to as the "upper cylindrical member"), and is a structure divided into multiple parts (two in this embodiment). These lower cylindrical member 31 and upper cylindrical member 33 are arranged on the rotor 20 side in the radial direction, inside a resin member 410 described later.

[0021] The lower cylindrical member 31 supports a lower bearing 51. The upper cylindrical member 33 supports an upper bearing 53. The lower cylindrical member 31 and the upper cylindrical member 33 are both arranged coaxially with the axis X as the central axis.

[0022] As shown in Figure 4, the lower cylindrical member 31 is formed by an inner cylindrical portion 311 arranged radially inward, an outer cylindrical portion 312 arranged radially outward, and a plurality of (e.g., four) spokes 313 as connecting portions that radially connect the inner cylindrical portion 311 and the outer cylindrical portion 312.

[0023] A plurality of recesses 313h (FIG. 3) are formed in the spokes 313 of the lower cylindrical member 31. The recesses 313h of the spokes 313 are attachment portions to which the drone body (not shown) is attached, and are provided with recesses into which fasteners such as bolts and screws are inserted.

[0024] The inner cylindrical portion 311 of the lower cylindrical member 31 has a step portion 311d (Figures 3 and 4) formed on the radially inner surface (hereinafter referred to as the "inner surface") 311n, and the lower bearing 51 is attached to this step portion 311d.

[0025] In this case, the lower bearing 51 is placed on the stepped portion 311d and fixed to the inner peripheral surface 311n of the inner cylindrical portion 311 by press-fitting, adhesive, or the like. The inner cylindrical portion 311 has a disk-shaped lid portion 311c integrally formed at its bottom portion to prevent the intrusion of dust, foreign matter, and the like from below. The lower end of the rotating shaft 10 is supported by the bearings 51 and 53, separated by a predetermined gap from the lid portion 311c of the lower cylindrical member 31.

[0026] The outer cylindrical portion 312 of the lower cylindrical member 31 is formed to be longer in the axial direction than the inner cylindrical portion 311. Two grooves 312m recessed inward in the radial direction are formed in the outer peripheral surface 312g of the outer cylindrical portion 312. The grooves 312m are concave grooves having a predetermined depth in the radial direction and a predetermined length in the axial direction. The two grooves 312m are formed in parallel with a predetermined distance apart in the axial direction. Furthermore, these grooves 312m are formed in an annular shape with respect to the outer peripheral surface 312g of the outer cylindrical portion 312.

[0027] The upper cylindrical member 33 has an integrated configuration of a cylindrical portion 331 and an upper lid portion 332. The outer and inner peripheral portions of the cylindrical portion 331 of the upper cylindrical member 33 have the same dimensions as the outer and inner peripheral portions of the outer cylindrical portion 312 of the lower cylindrical member 31, and are arranged coaxially with the lower cylindrical portion 31.

[0028] Two grooves 331m recessed radially inward are formed on the outer peripheral surface 331g of the cylindrical portion 331. The grooves 331m are recessed grooves having a predetermined depth in the radial direction and a predetermined length in the axial direction, and the two grooves 331m are formed in parallel with a predetermined distance apart in the axial direction. The grooves 331m are also formed annularly on the outer peripheral surface 331g of the cylindrical portion 331.

[0029] The two grooves 331m formed in the cylindrical portion 331 of the upper cylindrical member 33 and the two grooves 312m formed in the outer cylindrical portion 312 of the lower cylindrical member 31 are both concave grooves of the same shape and size. Note that the number of these grooves 312m, 331m does not necessarily have to be two, and may be one, or three or more. Furthermore, the grooves 312m, 331m do not necessarily have to be annular, and may be formed by a collection of multiple grooves that are interrupted intermittently in the circumferential direction.

[0030] A step 331d is formed on the top surface of the cylindrical portion 331 of the upper cylindrical member 33. The step 331d of the cylindrical portion 331 is formed on the side of the inner circumferential surface 331n of the cylindrical portion 331. The upper lid portion 332 is fitted onto the step 331d of the cylindrical portion 331.

[0031] The upper cover 332 of the upper cylindrical member 33 is integral with an annular portion 332a, a cylinder 332b that extends upward in the axial direction from the inner peripheral end of the portion 332a and supports the bearing 51, and an annular flange 332c that extends inner from the upper end of the cylinder 332b and engages with the bearing 51. In the upper cover 332, the annular portion 332a, the cylinder 332b, and the annular flange 332c form a support portion that supports the bearing 51.

[0032] An outer peripheral end of the annular portion 332a is disposed in a stepped portion 331d of the cylindrical portion 331, and the annular portion 332a is integrated with the cylindrical portion 331. Note that the flange 332c engages with the outer ring 53g of the bearing 53, but this is not limitative and the flange 332c may extend to a position facing the inner ring 53n of the bearing 53.

[0033] A stator 40 is provided between the lower cylindrical member 31 and the upper cylindrical member 33. The stator 40 has a stator core 401, an insulator 402, a plurality of coils 406, and a resin member 410. The resin member 410 covers the stator core 401, the insulator 402, and the plurality of coils 406, and fills in between the windings of the coils 406.

[0034] 5, stator core 401 is an electromagnetic steel plate formed by laminating silicon steel plates or the like as a magnetic material. However, stator core 401 may also be made of a non-magnetic material, resin, or the like. Stator core 401 includes an annular portion 4011 and a plurality of teeth 4012 extending from annular portion 4011 toward rotor 20. Ends 4013 of teeth 4012 on the rotor 20 side are magnetic pole portions.

[0035] End portion 4013 of stator core 401 has protrusions that protrude in the clockwise direction (direction of arrow e) and counterclockwise direction (direction of arrow f) in the circumferential direction.

[0036] An end (inner peripheral portion) 4013 of the stator core 401 is disposed on the outer cylindrical portion 312 of the lower cylindrical member 31 (FIG. 3). In addition, the cylindrical portion 331 of the upper cylindrical member 33 is disposed on the end 4013 of the stator core 401 (FIG. 3).

[0037] That is, the end 4013 of the stator core 401 is sandwiched between the outer cylindrical portion 312 of the lower cylindrical member 31 of the holder 30 and the cylindrical portion 331 of the upper cylindrical member 33, and they are integrally formed by bonding or the like. In this case, the holder 30 forms a part of the stator 40, and the holder 30 is disposed on the rotor 20 side with respect to the resin member 410.

[0038] Here, diameter d3 (FIG. 5) of a circle passing through the inner circumferential surface 4013n of the end portion 4013 of the stator core 401 is the same as diameter d1 (FIG. 4) of a circle passing through the inner circumferential surface 312n of the outer tubular portion 312 of the lower tubular member 31 and diameter d2 (FIG. 4) of a circle passing through the inner circumferential surface 331n of the tubular portion 331 of the upper tubular member 33. In other words, the inner circumferential surface 4013n of the end portion 4013, the inner circumferential surface 312n of the outer tubular portion 312 of the lower tubular member 31, and the inner circumferential surface 331n of the tubular portion 331 of the upper tubular member 33 are flush with each other in the axial direction.

[0039] As shown in FIG. 6, insulators 402 made of an insulating material are attached to teeth 4012 of stator core 401, and coils 406 are wound around teeth 4012 with insulators 402 interposed therebetween.

[0040] In stator core 401, a plurality of coils 406, the number of which is the same as the number of teeth 4012, are arranged side by side in the circumferential direction. Note that an insulating resin film may be formed on the surface of stator core 401, and the resin film may be used as an insulator.

[0041] An air gap (magnetic gap) g1 is formed between an inner peripheral surface 4013n of the end portion 4013 of the stator core 401 and an outer peripheral surface Mgn of the magnet Mg fixed to the outer peripheral surface 212g of the outer cylindrical portion 212 of the yoke 21.

[0042] In this case, as shown in Fig. 7, a closed space SP1 is formed by the lower cylindrical member 31, the upper cylindrical member 33, the stator core 401, the rotating shaft 10, and the bearings 51 and 53. The rotor 20 and the air gap g1 formed between the rotor 20 and the stator 40 are disposed in this closed space SP1. Note that in Fig. 7, the rotor 20 (yoke 21 and magnet Mg) is omitted from the illustration in order to clearly show the closed space SP1.

[0043] 3, resin member 410 of stator 40 covers stator core 401, insulator 402, and coil 406 from above and below, forming an annular (cylindrical) member as a whole. Resin member 410 contains, for example, an inorganic material having thermal conductivity such as alumina, an epoxy-based resin material, or the like.

[0044] The stator 40 is molded using a resin member 410 so that during injection molding, the molding resin fills two grooves 312m formed on the outer peripheral surface 312g of the outer cylindrical portion 312 of the lower cylindrical member 31 and two grooves 331m formed on the outer peripheral surface 331g of the cylindrical portion 331 of the upper cylindrical member 33.

[0045] The resin member 410 is connected to the lower cylindrical member 31 and the upper cylindrical member 33, which have grooves 312m and 331m. Specifically, a portion of the resin member 410 is inserted into the grooves 312m and 331m. Therefore, the lower cylindrical member 31 and the upper cylindrical member 33, which have grooves 312m and 331m, make it difficult for the resin member 410 to move up and down in the axial direction.

[0046] Furthermore, in part of resin member 410, resin fills the gaps between the windings (copper wire) of coil 406. Therefore, resin member 410 and coil 406 are tightly integrated with no gaps. In other words, heat generated in coil 406 is easily transferred to resin member 410.

[0047] Resin member 410 covers stator core 401, insulator 402, and coil 406 from above and below in the axial direction. That is, a portion of resin member 410 fills the gaps between the windings, and another portion of resin member 410 forms the side surfaces (inner surface, outer surface, upper surface, and lower surface) of the entire stator 40. This allows stator 40 to be protected from the outside, particularly from above and below. In this way, another portion of resin member 410 forms part of the side surfaces of stator 40.

[0048] In this case, motor 1 covers a portion of stator 40 including coil 406 with resin member 410 having relatively high heat dissipation properties, and resin member 410 is exposed to the outside and disposed so as to face blades 11a and 11b of propeller 11. This allows wind generated by blades 11a and 11b of propeller 11 to hit resin member 410 for cooling, thereby further cooling stator 40. Meanwhile, motor 1 may have resin member 410 partially exposing the upper and lower sides of coil 406.

[0049] As described above, the motor 1 has a closed space SP1 formed by the rotating shaft 10, the upper bearing 53, the lower cylindrical member 31, the upper cylindrical member 33, and the resin member 410. The closed space SP1 is divided into two spaces by the rotor 20 (connection portion 213). This prevents dust and foreign matter from entering the air gap g1 disposed in the closed space SP1. The closed space SP1 is not limited to this configuration and may be formed by the rotating shaft 10, the lower bearing 51, the lower cylindrical member 31, the upper cylindrical member 33, and the resin member 410. In this case, an opening is formed in the lower cylindrical member 31, and the rotating shaft 10 protrudes from this opening. A lid is provided on the upper cylindrical member 33, facing the end of the rotating shaft 10 on the upper cylindrical member 33 side.

[0050] A heat sink 60 is attached to an outer peripheral surface 4011g of the stator 40. The heat sink 60 is an annular member made of a metal such as an aluminum alloy. The heat sink 60 is fixed to an outer peripheral surface 4011g of the annular portion 4011 of the stator core 401 and an outer peripheral surface 410ag of an upper portion 410a of the resin member 410. The heat sink 60 may extend to an upper surface 410u of the resin member 410 (hereinafter referred to as the "upper surface"). The term "side surface" encompasses an upper surface (upper surface), a lower surface (lower surface), an outer peripheral surface (outer surface), and an inner peripheral surface (inner surface).

[0051] The heat sink 60 has a cylindrical portion 61 and a plurality of fins 62 extending radially outward from the outer peripheral surface of the cylindrical portion 61. The cylindrical portion 61 extends to a height that makes it flush with the upper surface 410u of the resin member 410. The fins 62 have approximately the same height as the annular portion 4011 of the stator core 401. Note that the fins 62 may have a height that reaches the upper surface 410u of the resin member 410 or a height that exceeds the upper surface 410u.

[0052] The cylindrical portion 61 of the heat sink 60 is in contact with the outer peripheral surface 410ag of the upper portion 410a of the resin member 410. In other words, the heat sink 60 is provided on the resin member 410 of the stator 40. Therefore, the heat sink 60 can easily transfer heat generated in the coil 406 from the upper portion 410a of the resin member 410 to the fins 62 and dissipate the heat from the fins 62.

[0053] Furthermore, since the fins 62 of the heat sink 60 are in contact with the outer surface 4011g of the annular portion 4011 of the stator core 401, the heat generated in the coil 406 is transferred directly from the annular portion 4011 of the stator core 401 to the fins 62, and can be easily dissipated from the fins 62.

[0054] In this way, the motor 1 is covered from above and below by a resin member 410 having a relatively high heat dissipation property, and the resin member 410 is arranged so as to face the blades 11a and 11b of the propeller 11 with the resin member 410 exposed to the outside.

[0055] As a result, motor 1 can directly transfer heat generated in coil 406 to resin member 410 and efficiently radiate the heat to the outside from resin member 410. Furthermore, in motor 1, wind from blades 11a and 11b of propeller 11 hits resin member 410, allowing resin member 410 to be air-cooled, so coil 406 can be efficiently cooled.

[0056] Furthermore, since the motor 1 has a heat sink 60 provided on the outer periphery of the resin member 410, in addition to the cooling of the resin member 410 by the wind from the propeller 11, the cooling of the resin member 410 can also be promoted by the fins 62 of the heat sink 60.

[0057] In the motor 1, the air gap (magnetic gap) g1 between the magnet Mg of the rotor 20 and the end 4013 of the stator core 401 is disposed in a closed space SP1. This prevents dust and foreign matter from entering the closed space SP1, and prevents foreign matter from entering the air gap g1. This reduces the risk of damage or breakdown of the motor 1.

[0058] According to the above configuration, in motor 1, coil 406 can be cooled via resin member 410, and the efficiency of the motor can be improved.

[0059] <Other embodiments> The motor of the present invention has been described above with reference to preferred embodiments, but the motor of the present invention is not limited to the configuration of the above embodiments. For example, the motor 1 of this embodiment is configured as an inner rotor brushless motor, but the present invention is also applicable to motors other than brushless motors. The present invention is also applicable to outer rotor motors. In the case of an outer rotor motor, a stator is disposed inside the rotor. For example, a heat sink may be provided on the outer peripheral surface of the rotor.

[0060] Furthermore, in this embodiment, the case where the heat sink 60 is fixed to the stator 40 has been described, but the present invention is not limited to this, and the stator 40 may not be provided with the heat sink 60 .

[0061] In addition, those skilled in the art can appropriately modify the motor of the present invention in accordance with conventional knowledge, change the combination of components, and remove unnecessary components depending on the application. 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]

[0062] 1...motor, 10...rotating shaft, 11...propeller, 20...rotor, 21...yoke, 211...inner cylindrical portion, 212 outer cylindrical portion, 213...connection portion, Mg...magnet, 30...holder, 31...lower cylindrical member, 311...inner cylindrical portion, 312...outer cylindrical portion, 312m...groove portion, 313...spoke as connecting portion, 33...upper cylindrical member, 331...cylindrical portion, 331m...groove portion, 332...upper cover portion, 40...stator, 401...stator core, 4011...annular portion, 4012...teeth portion, 4013...end portion, 402...insulator, 406...coil, 410...resin member, 410a...upper portion, 51, 53...bearing, g1...air gap (magnetic gap), SP1...closed space

Claims

1. A rotation axis; a propeller provided on the rotating shaft; a first bearing and a second bearing that support the rotating shaft; a holder including a cylindrical first member supporting the first bearing, a cylindrical second member supporting the second bearing, and a lid portion provided at a bottom of the cylindrical second member; A rotor, a stator facing the rotor in a radial direction of the rotor; Equipped with The stator is fixed to the cylindrical first member, the stator includes a magnetic body, a coil, and a resin member; an end of the rotating shaft on the second bearing side is spaced inward from the lid by a predetermined distance, a part of the resin member is inserted between the windings of the coil, another part of the resin member forms a side surface of the stator; another part of the resin member faces the propeller in the axial direction of the rotation shaft, A heat sink is provided on the resin member exposed to the outside. A motor mounted on a floating mobile body.

2. A rotating shaft, a propeller provided on the rotating shaft; a first bearing and a second bearing that support the rotating shaft; a holder including a cylindrical first member supporting the first bearing, a cylindrical second member supporting the second bearing, and a lid portion provided at a bottom of the cylindrical second member; a rotor having an annular member and a magnet fixed to an outer peripheral surface of the rotary shaft; a stator facing the rotor in a radial direction of the rotor; Equipped with the annular member includes an inner cylindrical portion, an outer cylindrical portion, and a connecting portion connecting the inner cylindrical portion and the outer cylindrical portion, the magnet is attached to the outer circumferential surface of the outer cylindrical portion, The stator is fixed to the cylindrical first member, the stator includes a magnetic body, a coil, and a resin member; an end of the rotating shaft on the second bearing side is spaced inward from the lid by a predetermined distance, The stator faces the propeller in the axial direction of the rotation shaft. A motor mounted on a floating mobile body.

3. Another part of the resin member forms a side surface of the stator on the propeller side. A motor mounted on the floating mobile body according to claim 1.

4. In the radial direction, the rotor is located on the rotation axis side relative to the stator. A motor mounted on the floating mobile body according to any one of claims 1 to 3.

5. In a radial direction, the cylindrical first member and the cylindrical second member are located on the rotor side with respect to the resin member. A motor mounted on the floating mobile body according to claim 1, 3 or 4.

6. the stator includes a plurality of coils including the coil; The plurality of coils are arranged side by side in the circumferential direction, the resin member has an annular shape that covers the plurality of coils, In a radial direction, the cylindrical first member and the cylindrical second member are located on the rotor side inside the resin member. A motor mounted on the floating mobile body according to any one of claims 1 and 3 to 5.

7. A closed space is formed by the cylindrical first member, the cylindrical second member, the first bearing, the second bearing, and the magnetic body, The closed space contains the rotor and a magnetic gap formed between the rotor and the magnetic body. A motor mounted on the floating mobile body according to any one of claims 1 to 6.

8. Another part of the resin member forms a part of the outer surface of the stator. A motor mounted on the floating mobile body according to claim 4.

9. the holder forms a part of the stator and is located on the rotor side relative to the resin member in the radial direction; A motor mounted on the floating mobile body according to claim 7.

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