Motor

Abstract

A motor (1) is provided with: a cover (10) that comprises a cylinder (11), an annular frame (12) that surrounds the cylinder (11), and a plurality of spokes (13) that link the cylinder (11) and the annular frame (12); and a rotor (50) that is attached to the cover (10). Two spokes (14, 15) of the plurality of spokes (13) extend from the cylinder (11) approaching the frame (12), and a portion (17) of the frame (12) and the two spokes (14, 15) are linked.

Description

Motor

[0001] The present invention relates to a motor.

[0002] For example, in so-called outer rotor motors, it is known that branch ports are formed on the inner bottom wall on the extension of the spokes to reduce noise. Furthermore, in so-called outer rotor motors, large loads are placed on the screw holes used to secure the motor to other components. Therefore, it is known to attach reinforcing rings to the mounting legs that have mounting holes.

[0003] JP 2011-67053 A JP 2019-30182 A

[0004] However, the formation of branching openings in the inner bottom wall may reduce the strength of the spokes, and adding a reinforcing member to the motor housing increases the weight of the motor.

[0005] One object of the present invention is to provide a motor that can ensure strength, and another object of the present invention is to provide a motor that can be made lighter.

[0006] In one aspect, the motor includes a cover having a cylinder, an annular frame surrounding the cylinder, and a plurality of spokes connecting the cylinder and the annular frame, and a rotor attached to the cover. Two of the plurality of spokes extend radially from the cylinder toward the frame, and a portion of the frame is connected to the two spokes. In another aspect, the motor includes a housing having a cylinder, an annular frame surrounding the cylinder, and a plurality of spokes connecting the cylinder and the annular frame, and a stator attached to the housing. In the radial direction, the outer periphery of the cylinder includes a protrusion extending toward the frame. In the radial direction, two spokes branch off from the protrusion and extend toward the frame. In the circumferential direction, the two spokes connect to two portions of the frame, and the two portions of the frame are located at different positions from each other in the circumferential direction.

[0007] According to one aspect, the strength of the motor can be ensured, and according to another aspect, the weight of the motor can be reduced.

[0008] FIG. 1 is a perspective view showing an example of a device using a motor according to an embodiment. FIG. 2 is a perspective view showing an example of a motor according to an embodiment. FIG. 3 is an exploded perspective view showing an example of a motor according to an embodiment. FIG. 4 is a top view showing an example of a motor according to an embodiment. FIG. 5 is a cross-sectional perspective view showing an example of a motor according to an embodiment. FIG. 6 is a top view showing an example of a cover according to an embodiment. FIG. 7 is a side cross-sectional view showing an example of a cover according to an embodiment. FIG. 8 is a top view showing an example of a housing according to an embodiment. FIG. 9 is a side cross-sectional view showing an example of a housing according to an embodiment.

[0009] An embodiment of a motor disclosed herein will be described in detail below with reference to the drawings. Note that the dimensional relationships and ratios of elements in the drawings may differ from reality. The drawings may also include portions where the dimensional relationships and ratios differ. To facilitate understanding, each drawing may illustrate a coordinate system that includes at least one of the axial direction (the rotational axis direction of the motor 1), radial direction, and circumferential direction of the motor 1, which will be described later. In the following description, the rotational axis direction of the motor 1 may be simply referred to as the "axial direction."

[0010] [Embodiment] A motor 1 according to an embodiment is used in a device such as a drone propeller, as shown in Fig. 1. Fig. 1 is a perspective view showing an example of a device using a motor according to an embodiment. As shown in Fig. 1, a pair of propellers 61 and 62 are fixed to the motor 1 according to the embodiment by a holder 70.

[0011] As shown in Figures 2 and 3, the motor 1 includes a cover 10 and a housing 20. Figure 2 is a perspective view showing an example of a motor according to an embodiment. Figure 3 is an exploded perspective view showing an example of a motor according to an embodiment. As shown in Figures 2 and 3, when the holder 70 side shown in Figure 1 is defined as the positive axial direction and the motor 1 side is defined as the negative axial direction, the cover 10 is located on the positive axial side of the motor 1, and the housing 20 is located on the negative axial side of the motor 1.

[0012] 4 and 5, the motor 1 includes a stator 40 attached to the housing 20 and a rotor 50 attached to the cover 10. FIG. 4 is a top view showing an example of a motor according to an embodiment. FIG. 5 is a cross-sectional perspective view showing an example of a motor according to an embodiment. FIG. 5 shows a cross section taken along line A-A in FIG. 4. The motor 1 described in the embodiment is, for example, an outer rotor brushless motor in which the stator 40 is located radially inside the rotor 50.

[0013] The stator 40 is a substantially annular member, and is fixed to the radially outer side of the housing 20 as shown in Fig. 5. The stator 40 may be fixed to the housing 20 via other members (for example, a resin such as an adhesive (a joining member) or screws (a fastening member)).

[0014] As shown in Figure 5, the stator 40 comprises a magnetic body 41 having an annular portion (hereinafter referred to as a yoke) and a plurality of magnetic pole portions (hereinafter referred to as teeth), and a plurality of coils 42 wound around the plurality of magnetic pole portions.

[0015] The yoke is formed radially outside the stator 40 and has an annular outer shape. Teeth of the magnetic body 41 that face the rotor 50 radially protrude radially inward from the yoke. The magnetic body 41 is formed by punching out flat plate-shaped members made of a magnetic material such as electromagnetic steel plate and stacking multiple members in the axial direction. The coil 42 is wound around the magnetic body 41, for example, via an insulator 43. Note that detailed illustrations of the magnetic body 41, the coil 42, and the insulator 43 may be omitted in the drawings other than FIG. 5 .

[0016] The rotor 50 is a cylindrical member formed from a magnetic material such as an electromagnetic steel plate and extending in the axial direction. As shown in Fig. 4, the stator 40 and the rotor 50 face each other in the radial direction with a gap G0 between them. The rotor 50 is equipped with magnets and rotates in response to magnetic forces generated in the stator 40. Note that, in the following description, the magnets equipped in the rotor 50 may not be shown in the drawings.

[0017] 3, the rotor 50 is formed with engaging portions 51p to 51u that protrude in the positive axial direction. Each of the engaging portions 51p to 51u engages with an engaged portion 18p to 18u formed on the cover 10, respectively. In this configuration, the rotor 50 is attached to the cover 10, and the cover 10 rotates in conjunction with the rotor 50. The engaging portions 51p to 51u are formed in the same number as the engaged portions 18p to 18u formed on the cover 10, for example. The engaging portions 51p to 51u are an example of a portion of the rotor.

[0018] 3, the cover 10 has a tube 11, an annular frame 12, and a plurality of spokes 13. The housing 20 has a tube 21, an annular frame 22, and a plurality of spokes 23.

[0019] The cover 10 and the housing 20 are made of a metal such as aluminum. The cylinder 11, frame 12, and spokes 13 of the cover 10 are integrally formed by, for example, molding, and the cylinder 21, frame 22, and spokes 23 of the housing 20 are also integrally formed by, for example, molding.

[0020] The tube 11 of the cover 10 is formed on the radially inner side of the cover 10. As shown in Fig. 3, the tube 11 includes an outer peripheral portion 111, a rotating shaft 112, and an inner peripheral portion 120 including an upper surface portion 119. The upper surface portion 119 is formed on the positive axial side. The rotating shaft 112 protrudes from the tube 11 on the negative axial side. The rotating shaft 112 is formed hollow as shown in Fig. 5, for example, but may also be formed solid.

[0021] The cylinder 21 of the housing 20 is formed on the radially inner side of the housing 20. As shown in Fig. 3, the cylinder 21 has an outer peripheral surface 211 and an inner peripheral surface 212. The outer peripheral surface 211 is an example of the outer periphery of the cylinder.

[0022] The motor 1 also includes a pair of bearings 31 and 32. As shown in Figures 3 and 5, the bearings 31 and 32 are press-fitted into the inner circumferential surface 212 of the cylinder 21 of the housing 20. Thereafter, the rotating shaft 112 of the cover 10 is press-fitted into the inner diameter sides of the bearings 31 and 32, as shown in Figures 3 and 5. That is, in this embodiment, the rotating shaft 112, which is part of the cylinder 11 of the cover 10, is housed in the bearings 31 and 32, and the cylinder 21 of the housing 20 houses the bearings 31 and 32. In this configuration, the rotating shaft 112 of the cover 10 is rotatably supported by the cylinder 21 of the housing 20 via the bearings 31 and 32.

[0023] As shown in Figures 6 and 7, in the cover 10, an annular frame 12 is formed to surround the tube 11, and a plurality of spokes 13 connect the tube 11 and the annular frame 12. Figure 6 is a top view showing an example of the cover in this embodiment. Figure 7 is a side cross-sectional view showing an example of the cover in this embodiment. Figure 7 shows a cross-section of the motor 1 taken along line B-B in Figure 6.

[0024] The multiple spokes 13 extend from the tube 11 toward the frame 12, and include two spokes 14 and 15. In the following, one of the spokes 13, 14, may be referred to as a first spoke 14, and the other spoke 15 may be referred to as a second spoke 15.

[0025] Of the multiple spokes 13, a first spoke 14 and a second spoke 15 extend radially from the tube 11 toward the frame 12. In the embodiment, the first spoke 14 extends from a connection portion 16, which is an example of a portion of the tube 11, toward the frame 12, and the second spoke 15 extends from another portion of the tube 11 toward the frame 12, so that the first spoke 14 and the second spoke 15 extend from the tube 11 toward the frame 12 toward the frame 12. In other words, the first spoke 14 and the second spoke 15 extend in directions that intersect with each other from the tube 11 toward the frame 12 and are connected to the frame 12.

[0026] In the embodiment, the tube 11 of the cover 10 includes six connection portions 16a to 16f. When the connection portions 16a to 16f are not to be distinguished from one another, they may be simply referred to as connection portions 16.

[0027] Loads are likely to be applied to the portions (ends) of the spokes 13 that connect to the tube 11. In this embodiment, the first spoke 14 and the second spoke 15 share an end at the connection portion 16, thereby ensuring strength.

[0028] Furthermore, extensions of the spokes 13 do not pass through the center C1 of the tube 11. For example, as shown in Figure 6, extension E4b of the first spoke 14b passes through a portion of the tube 11 that is far from the center C1 in the radial direction. Furthermore, at connection portion 16b where the first spoke 14b is connected, two spokes 14b and 15b intersect, and the other spokes 13 are connected to a portion of the tube 11 that is far from connection portion 16b. This configuration prevents the load of three or more spokes 13 from concentrating at one point.

[0029] Note that extension line E4b of spoke 14b intersects with extension lines of other spokes 13 at a portion other than the center C1 of the tube 11. For example, extension line E4b intersects with extension line E4c of spoke 14c at a portion of the top surface 119 of the tube 11, and intersects with extension line E5d of spoke 15d at a position between the tube 11 and the frame 12. Furthermore, extension line E4b of spoke 14b and extension line E4e of spoke 14e are parallel to each other.

[0030] Furthermore, first through holes 19A to 19D and second through holes 19v to 19y are formed in the upper surface portion 119 of the tube 11. In the embodiment, the first through holes 19A to 19D are formed so as to have a substantially circular cross-sectional shape, and the second through holes 19v to 19y are formed so as to have a substantially circular cross-sectional shape with a larger diameter than the cross-sectional shape of the first through holes 19A to 19D. Note that hereinafter, when the first through holes 19A to 19D and the second through holes 19w to 19y are not to be distinguished from each other, they may be simply referred to as through holes 19. The through holes 19 are formed, for example, at equal intervals in the circumferential direction.

[0031] 6 is fitted with a screw for fixing an external member, such as the holder 70 shown in FIG. 1, to the cover 10. In this configuration, the cover 10 rotates together with the propellers 61 and 62 fixed via the holder 70. Note that the shape of the through hole 19 is not limited to the through hole shown in FIG. 4 and may be, for example, a recess, as long as the shape allows the holder 70 or the like to be fixed directly or via another member, such as a screw.

[0032] Alternatively, a portion of the frame 12 may be connected to the first spoke 14 and the second spoke 15. For example, as shown in Fig. 6, the first spoke 14a may intersect with the second spoke 15b at an intersection 17p formed in a portion of the frame 12. In this embodiment, the same number of intersections 17p to 17u as the number of connection portions 16a to 16f are formed. Note that, hereinafter, when the intersections 17p to 17u are not to be distinguished from one another, they may be simply referred to as intersections 17.

[0033] In the embodiment, the first spoke 14 and the second spoke 15 intersect at the intersections 17p to 17u radially inward from the frame 12. For example, as shown in FIG. 6 , the intersection of the first spoke 14b and the second spoke 15c is located radially inward from the frame 12 by a length L1. The length L1 is smaller than the outer shape of the frame 12 and smaller than the distance between the frame 12 and the tube 11. The range of the length L1 may be smaller than the length of the first spoke 14b or the length of the second spoke 15c, and may be greater than 1 / 10 of the length of the first spoke 14b or the length of the second spoke 15c.

[0034] According to this configuration, the intersecting portions 17p to 17u can be made larger in the radial direction, and therefore the strength of the intersecting portions 17p to 17u can be easily ensured.

[0035] The plurality of spokes 13 includes two spokes 14 and 15 and a spoke 15 adjacent to one of the two spokes 14 and 15 in the circumferential direction. For example, as shown in Fig. 6, the first spoke 14a is adjacent to the second spokes 15a and 15b in the circumferential direction, and the second spoke 15a is adjacent to the first spokes 14a and 14f in the circumferential direction.

[0036] Furthermore, two of the spokes 13, 14 and 15, for example, one spoke 14 or 15 and the adjacent spoke 15 or 14, extend from the frame 12 toward a portion of the tube 11. For example, as shown in FIG. 6 , the first spoke 14 a and the second spoke 15 a extend from the frame 12 toward a connection portion 16 a, which is an example of a portion of the tube 11.

[0037] In addition, in the radial direction, two spokes 14 and 15 of the multiple spokes 13 extend from the tube 11 toward the frame 12. For example, as shown in Figure 6, the first spoke 14a extends toward an intersection 17p that is part of the frame 12, and the second spoke 15a extends toward an intersection 17u that is different from the intersection 17p.

[0038] In such a configuration, for example, one spoke 14a intersects with another spoke 15b at intersection 17p, and one spoke 15a intersects with another spoke 14f at intersection 17u, which is another part of the frame 12, at connection 16a, which is part of the tube 11.

[0039] 6, the intersecting portion 17, which is a part of the frame 12, may include engaged portions 18p to 18u that engage with portions 51p to 51u of the rotor 50. The engaged portions 18p to 18u are an example of a part of the frame. That is, the cover 10 engages with the engaging portions 51p to 51u, which are a part of the rotor 50, at the engaged portions 18p to 18u. With this configuration, stress applied from the rotor 50 via the engaging portions 51p to 51u can be dispersed between the frame 12 and the intersecting portions 17p to 17u.

[0040] Furthermore, the cylinder 11 preferably has a large size (thickness) in the axial direction to ensure the strength of the through-hole 19. In this case, the spokes 13 in this embodiment are curved in the axial direction so as to be convex from the stator 40 side toward the cylinder 11 (in the direction away from the stator 40). Specifically, as shown in FIG. 7 , the first spokes 14 and the second spokes 15 are curved from the negative axial side where the stator 40 is located toward the positive axial side where the top surface 119 of the cylinder 11 of the cover 10 is located. In this case, the spokes 13 are located axially on the negative axial side of the top surface 119. Furthermore, the top surface 119 of the cylinder 11 and the spokes 13 are formed so as to be continuously connected.

[0041] This configuration distributes the load applied to the first spokes 14 and the second spokes 15. Furthermore, an axial distance H1 can be secured between the radially outer sides of the first spokes 14 and the second spokes 15 and the upper surface portion 119 of the tube 11. This prevents the propeller 61 or 62, etc., attached to the upper surface portion 119 from coming into contact with the spokes 13 or the frame 12.

[0042] Next, as shown in Figures 8 and 9, in the housing 20, an annular frame 22 is formed to surround the tube 21, and as shown in Figure 3, a plurality of spokes 23 connect the tube 21 and the annular frame 22. Figure 8 is a top view showing an example of a housing in this embodiment. Figure 9 is a side cross-sectional view showing an example of a housing in this embodiment. Figure 9 shows a cross-section taken along line CC in Figure 8.

[0043] As shown in Fig. 8, the cylinder 21 of the housing 20 is formed with a flange 216 that protrudes radially outward from the outer circumferential surface 211. Furthermore, the outer circumferential surface 211 of the cylinder 21 is provided with a protrusion 26 that extends radially toward the frame 22. In this embodiment, the protrusion 26 is formed integrally with the flange 216. As shown in Fig. 5, the protrusion 26 is formed on the negative side in the axial direction. As shown in Fig. 8, the cylinder 21 is provided with four protrusions 26A to 26D that are formed at approximately equal intervals in the circumferential direction.

[0044] Furthermore, two spokes 24 and 25 branch out from the protrusion 26 in the radial direction and extend toward the frame 22. Note that, hereinafter, when the two spokes 24 and 25 need to be distinguished from each other, they may be referred to as the first spoke 24 and the second spoke 25. In this embodiment, the first spoke 24 branches out in a clockwise direction (CW) when viewed from above, and the second spoke 25 branches out in a counterclockwise direction (CCW) when viewed from above.

[0045] In the circumferential direction, the two spokes 24 and 25 are connected to two connection portions 27 and 28 of the frame 22. In this embodiment, the number of connection portions 27 and 28 is the same as the number of first spokes 24 and second spokes 25. That is, the housing 20 has four connection portions 27A to 27D and four connection portions 28A to 28D. The connection portions 27 and 28 are an example of two portions.

[0046] 8, first spoke 24A branching off from protrusion 26A of tube 21 is connected to connection portion 27A formed on frame 22, and second spoke 25A is connected to connection portion 28A. Similarly, first spoke 24B branching off from protrusion 26B is connected to connection portion 27B, and second spoke 25B is connected to connection portion 28B. Furthermore, first spoke 24D branching off from protrusion 26D is connected to connection portion 27D, and second spoke 25D is connected to connection portion 28D.

[0047] 8, the two portions 27A and 28A of the frame 22 are located at different positions in the circumferential direction. For example, as shown in FIG. 8, an opening GA is formed in the circumferential direction between the connection portions 27A and 28A. An opening Gv is formed in the circumferential direction between the connection portions 27A and 28B. Similarly, the connection portions 27B to 27D and the connection portions 28A to 28D face the other connection portion 27 or 28 in the circumferential direction via the openings GB to GD or the openings Gw to Gy.

[0048] Furthermore, a through hole 29 for fixing to another member is formed in the protruding portion 26. The through hole 29 is an example of an engaged portion.

[0049] For example, a through-hole 29A is formed in the protrusion 26A. Similarly, through-holes 29B to 29D are formed in the protrusions 26B to 26D, respectively. Screws or the like for fastening other devices, such as a drone arm (not shown), are inserted through the through-holes 29A to 29D. The shape of the through-holes 29A to 29D is not limited to the through-hole shown in FIG. 8 , and may be, for example, a recess, as long as it allows other devices to be fastened directly or via other members, such as screws. Note that, as shown in FIG. 8 , another through-hole 29y may be formed in any of the eight connection portions 27A to 27D and 28A to 28D. The through-hole 29y is provided to fasten a cable k or the like connected to the motor 1. For example, a cable fastening jig (not shown) is attached to the through-hole 29y, and the cable k extending from the lower part of the motor 1 is fastened to the jig. The through-holes 29A to 29D shown in FIG. 8 may also be formed to adjust the rigidity of the protrusions 26A to 26D.

[0050] In the housing 20, the portions through which screws or the like are inserted and the ends where the spokes 23 connect to the tube 21 are both portions that are prone to loads. In this embodiment, the through holes 29 through which screws or the like are inserted and the ends of the first spokes 24 and the second spokes 25 are all formed in the protruding portion 26. This allows the portions that require reinforcement to be shared in the protruding portion 26, thereby suppressing an increase in the weight of the housing 20.

[0051] 9, the cross section of the spoke 23 in the circumferential direction becomes smaller from the tube 21 toward the frame 22. For example, as shown in FIG. 9, the cross section of the spokes 25A and 24B has a thickness T2 on the frame 22 side that is smaller than a thickness T1 on the tube 21 side. Note that in FIG. 9, the connection portions 27A and 28B and the opening Gv are located behind the tube 21 and are not visible.

[0052] In this configuration, the strength can be ensured by increasing the thickness in the axial direction near the engaging portion where the load is large, and the thickness can be reduced on the radially outer side to reduce the weight of the housing 20. In addition, since the spokes 23 are curved in the axial direction, the load acting on the spokes 23 is distributed.

[0053] Furthermore, the flange 216 and protrusion 26 of the tube 21, the spokes 23, and the frame 22 are formed to be continuously connected in a curved shape. For example, as shown in Fig. 8, the spokes 24 and 25 are formed to be curved in the radial direction. Furthermore, as shown in Fig. 9, the connecting portions 27 and 28 also have a curved shape relative to the spoke 23. With this configuration, the load is not concentrated in the bending portion, and the load can be distributed among the flange 216, the protrusion 26, the spokes 23, and the frame 22.

[0054] As described above, the motor 1 in this embodiment includes a cover 10 having a cylinder 11, an annular frame 12 surrounding the cylinder 11, and a plurality of spokes 13 connecting the cylinder 11 and the annular frame 12, and a rotor 50 attached to the cover 10. Two spokes 14, 15 of the plurality of spokes 13 extend radially from the cylinder 11 toward the frame 12, and the two spokes 14, 15 are connected to an intersection 17 that is part of the frame 12. This configuration ensures the strength of the cover.

[0055] The motor 1 in this embodiment includes a housing 20 having a cylinder 21, an annular frame 22 surrounding the cylinder 21, and a plurality of spokes 23 connecting the cylinder 21 and the annular frame 22, and a stator 40 attached to the housing 20. The outer peripheral surface 211 of the cylinder 21 includes a protrusion 26 extending radially toward the frame 22. Two spokes 24, 25 branch off from the protrusion 26 and extend radially toward the frame 22. The two spokes 24, 25 connect to two portions 27, 28 of the frame 22 in the circumferential direction, and the two portions 27, 28 of the frame are located at different positions in the circumferential direction. This configuration allows the motor to be lightweight.

[0056] [Modifications] While the configuration of the embodiment has been described above, the embodiment is not limited to this. For example, the cover 10 and the housing 20 can be implemented separately, the cover 10 in the embodiment can be combined with a housing of another shape, and the housing 20 in the embodiment can be combined with a cover of another shape.

[0057] 9 is formed to be equal to or less than the thickness T2 of the spoke 23 on the frame side in the embodiment, but is not limited to this and may be formed so that T3 > T2. Also, as shown in FIG. 9, the spoke 23 is formed so that both the portion P1 on the positive axial side and the portion P2 on the negative axial side are curved, but is not limited to this and may have a shape in which only one of them is curved.

[0058] While the present invention has been described above based on the embodiments and modifications, it goes without saying that the present invention is not limited to the embodiments and modifications, and various modifications are possible without departing from the spirit of the present invention. Such modifications without departing from the spirit of the present invention are also included in the technical scope of the present invention, and this will be clear to those skilled in the art from the description of the claims.

[0059] 1 motor, 10 cover, 11 cylinder, 111 outer peripheral portion, 112 rotating shaft, 119 upper surface portion, 120 inner peripheral portion, 12 frame, 13 spokes, 14 first spokes, 15 second spokes, 16 connection portion, 17p to 17u intersection portion, 18p to 18u engaged portion, 19 through hole, 20 housing, 21 cylinder, 211 outer peripheral surface, 212 inner peripheral surface, 22 frame, 23 spokes, 24 first spokes, 25 second spokes, 26 protrusion portion, 27, 28 connection portion, 29 through hole, 31, 32 bearing, 40 stator, 50 rotor, 51p to 51u engagement portion, 61, 62 propeller, 70 holder

Claims

1. A motor comprising: a cover having a cylinder, an annular frame surrounding the cylinder, and a plurality of spokes connecting the cylinder and the annular frame; and a rotor attached to the cover, wherein two of the plurality of spokes extend radially from the cylinder toward the frame, and the two spokes are connected to a portion of the frame.

2. The motor according to claim 1, further comprising a stator, wherein the spokes are curved so as to be convex from the stator side towards the cylinder.

3. A motor as described in claim 1 or 2, wherein two of the plurality of spokes extend from the frame toward a portion of the cylinder, and the portion of the frame has an engaged portion that engages with a portion of the rotor.

4. A motor as described in claim 1 or 2, wherein the plurality of spokes comprises the two spokes and a spoke adjacent to one of the two spokes in the circumferential direction, and the one spoke and the spoke adjacent to the one spoke extend from the frame toward a portion of the cylinder.

5. A motor comprising: a housing having a cylinder, an annular frame surrounding the cylinder, and a plurality of spokes connecting the cylinder and the annular frame; and a stator attached to the housing, wherein in the radial direction, the outer periphery of the cylinder has a protrusion extending toward the frame, in the radial direction, two spokes branch off from the protrusion and extend toward the frame, in the circumferential direction, the two spokes are connected to two parts of the frame, and in the circumferential direction, the two parts of the frame are at different positions from each other.

6. The motor according to claim 5, wherein the cross section of said spokes in the circumferential direction decreases from said cylinder toward said frame.

7. The motor according to claim 5 or 6, wherein the protruding portion is formed with an engaged portion that is engaged with another member.

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