Motor

Abstract

To secure strength of a motor.SOLUTION: A motor includes: a cover having a cylinder, an annular frame enclosing the cylinder, and a plurality of spokes connecting the cylinder with the annular frame; and a rotor attached to the cover. In a radial direction, two spokes of the plurality of spokes extend from the cylinder to come close to the frame and one portion of the frame is connected to the two spokes.SELECTED DRAWING: Figure 6

Description

[Technical field]

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

[0002] For example, in a so-called outer rotor type motor, it is known that in order to reduce noise, branch ports are formed on the inner peripheral bottom wall on the extension lines of the spoke portions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-67053 A [Patent Document 2] JP 2019-30182 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the formation of branch openings in the inner bottom wall may reduce the strength of the spokes.

[0005] One object of the present invention is to provide a motor that can ensure strength. [Means for solving the problem]

[0006] In one embodiment, 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. In the radial direction, two of the plurality of spokes extend from the cylinder toward the frame, and the two spokes are connected to a portion of the frame.

[0007] According to one embodiment, strength can be ensured. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing an example of a device using a motor according to an embodiment. [Diagram 2] FIG. 2 is a perspective view illustrating an example of a motor according to an embodiment. [Diagram 3] FIG. 3 is an exploded perspective view illustrating an example of a motor according to an embodiment. [Figure 4] FIG. 4 is a top view illustrating an example of a motor according to an embodiment. [Diagram 5] FIG. 5 is a cross-sectional perspective view illustrating an example of a motor according to an embodiment. [Figure 6] FIG. 6 is a top view illustrating an example of a cover in the embodiment. [Figure 7] FIG. 7 is a side cross-sectional view showing an example of a cover in the embodiment. [Figure 8] FIG. 8 is a top view illustrating an example of a housing in the embodiment. [Figure 9] FIG. 9 is a side cross-sectional view showing an example of a housing in the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the motor disclosed in the present application will be described in detail with reference to the drawings. Note that the dimensional relationships of the elements in the drawings, the ratios of the elements, etc. may differ from reality. The drawings may also include parts in which the dimensional relationships and ratios of the elements differ. To facilitate understanding of the description, each drawing may show a coordinate system including at least one of the axial direction (the direction of the rotational axis of the motor 1), radial direction, and circumferential direction of the motor 1, which will be described later. In addition, hereinafter, the direction of the rotational axis of the motor 1 may be simply referred to as the "axial direction."

[0010] [Embodiment] The motor 1 in the 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 the motor in the embodiment. As shown in Fig. 1, a pair of propellers 61 and 62 are fixed to the motor 1 in 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 in an embodiment. Figure 3 is an exploded perspective view showing an example of a motor in an embodiment. As shown in Figures 2 and 3, when the holder 70 side shown in Figure 1 is the positive direction in the axial direction and the motor 1 side is the negative direction, the cover 10 is located on the positive side in the axial direction of the motor 1, and the housing 20 is located on the negative side in the axial direction of the motor 1.

[0012] As shown in Fig. 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 in an embodiment. Fig. 5 is a cross-sectional perspective view showing an example of a motor in an embodiment. Fig. 5 shows a cross section taken along line AA in Fig. 4. The motor 1 described in the embodiment is, for example, an outer rotor type 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 outside in the radial direction of the housing 20 as shown in Fig. 5. The stator 40 may be fixed to the housing 20 via another member (for example, a resin such as an adhesive (a joining member) or a screw (a fastening member)).

[0014] As shown in FIG. 5, the stator 40 includes 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 on the radial outside of the stator 40 and has an annular outer shape. Teeth of the magnetic body 41 facing the rotor 50 in the radial direction protrude from the yoke to the radial inside. The magnetic body 41 is formed by punching a flat plate-shaped member made of a magnetic material such as an electromagnetic steel plate and stacking a plurality of them in the axial direction. The coil 42 is wound around the magnetic body 41, for example, via an insulator 43. Note that in the drawings other than FIG. 5, detailed illustrations of the magnetic body 41, the coil 42, and the insulator 43 may be omitted.

[0016] The rotor 50 is a cylindrical member formed of 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 therebetween. The rotor 50 includes a magnet and rotates in response to a magnetic force generated in the stator 40. In the following description, the magnets included in the rotor 50 may be omitted from illustration.

[0017] 3, the rotor 50 is formed with engaging portions 51p to 51u that protrude in the positive axial direction. The engaging portions 51p to 51u engage with engaged portions 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 tube 11, frame 12 and multiple spokes 13 of the cover 10 are integrally formed by, for example, die processing, and the tube 21, frame 22 and multiple spokes 23 of the housing 20 are also integrally formed by, for example, die processing.

[0020] The tube 11 of the cover 10 is formed on the inside in the radial direction of the cover 10. As shown in Fig. 3, the tube 11 includes an outer circumferential portion 111, a rotating shaft 112, and an inner circumferential portion 120 including an upper surface portion 119. The upper surface portion 119 is formed on the positive side in the axial direction. The rotating shaft 112 protrudes from the tube 11 on the negative side in the axial direction. The rotating shaft 112 is formed to be hollow as shown in Fig. 5, for example, but may be formed to be 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 circumferential surface 211 and an inner circumferential surface 212. The outer circumferential 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. The bearings 31 and 32 are press-fitted into the inner circumferential surface 212 of the tube 21 of the housing 20 as shown in Figs. 3 and 5. Then, 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 Figs. 3 and 5. That is, in the embodiment, the rotating shaft 112, which is a part of the tube 11 of the cover 10, is accommodated in the bearings 31 and 32, and the tube 21 of the housing 20 accommodates the bearings 31 and 32. In this configuration, the rotating shaft 112 of the cover 10 is rotatably supported by the tube 21 of the housing 20 via the bearings 31 and 32.

[0023] As shown in Fig. 6 and Fig. 7, in the cover 10, an annular frame 12 is formed to surround a tube 11, and a plurality of spokes 13 connect the tube 11 and the annular frame 12. Fig. 6 is a top view showing an example of a cover in an embodiment. Fig. 7 is a side cross-sectional view showing an example of a cover in an embodiment. Fig. 7 shows a cross section taken along line BB in Fig. 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, the spoke 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] In the radial direction, the first spoke 14 and the second spoke 15 of the multiple spokes 13 extend from the tube 11 toward the frame 12 so as to approach each other. 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, and the first spoke 14 and the second spoke 15 extend from the tube 11 toward the frame 12 so as to approach each other. In other words, the first spoke 14 and the second spoke 15 extend from the tube 11 toward the frame 12 in directions that intersect with each other, and are connected to the frame 12.

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

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

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

[0029] Furthermore, extension line E4b of spoke 14b intersects with an extension line of another spoke 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 upper surface portion 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] In addition, first through holes 19A to 19D and second through holes 19v to 19y are formed in the upper surface portion 119 of the cylinder 11. In the embodiment, the first through holes 19A to 19D are formed to have a substantially circular cross-sectional shape, and the second through holes 19v to 19y are formed 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. In the following description, the first through holes 19A to 19D and the second through holes 19w to 19y may be simply referred to as through holes 19 when they are not to be distinguished from each other. The through holes 19 are formed, for example, at equal intervals in the circumferential direction.

[0031] A screw for fixing an external member such as the holder 70 shown in Fig. 1 to the cover 10 is screwed into the through hole 19 shown in Fig. 6. 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 holder 70 or the like can be fixed directly or via another member such as a screw.

[0032] Also, the first spoke 14 and the second spoke 15 may be connected to a portion of the frame 12. 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 the embodiment, the intersections 17p to 17u are formed in the same number as the connection portions 16a to 16f.

[0033] In the embodiment, the first spoke 14 and the second spoke 15 intersect at the intersections 17p to 17u on the radially inner side of the frame 12. For example, as shown in Fig. 6, the portion where the first spoke 14b and the second spoke 15c intersect 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 large in the radial direction, so that the strength of the intersecting portions 17p to 17u can be easily ensured.

[0035] Further, the plurality of spokes 13 includes two spokes 14 and 15, and a spoke 15 and 14 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 spoke 15 or 14 adjacent to the one spoke, extend from the frame 12 so as to approach one portion of the tube 11. For example, the first spoke 14a and the second spoke 15a extend from the frame 12 so as to approach one portion of the tube 11, as shown in FIG.

[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 Fig. 6, the first spoke 14a extends toward an intersection 17p that is a 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 at an intersection 17p and one spoke 15a intersects at an intersection 17u which is another part of the frame 12, and these intersect at a connection portion 16a which is part of the tube 11.

[0039] 6, the intersection 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, the stress applied from the rotor 50 via the engaging portions 51p to 51u can be dispersed between the frame 12 and the intersections 17p to 17u.

[0040] Moreover, in order to ensure the strength of the through-hole 19, it is preferable that the size (thickness) of the tube 11 in the axial direction is large. In this case, the spokes 13 in the embodiment are curved in the axial direction so as to be convex from the stator 40 side toward the tube 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 disposed toward the positive axial side where the top surface portion 119 of the tube 11 of the cover 10 is located. In this case, the spokes 13 are located on the negative axial side of the top surface portion 119 in the axial direction. Moreover, the top surface portion 119 of the tube 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. In addition, a 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 cylinder 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 Fig. 8 and Fig. 9, in the housing 20, an annular frame 22 is formed to surround the tube 21, and as shown in Fig. 3, a plurality of spokes 23 connect the tube 21 and the annular frame 22. Fig. 8 is a top view showing an example of a housing in the embodiment. Fig. 9 is a side cross-sectional view showing an example of a housing in the embodiment. Fig. 9 shows a cross section taken along line CC in Fig. 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, in the radial direction, the outer circumferential surface 211 of the cylinder 21 is provided with a protrusion 26 that extends toward the frame 22. In the 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. In the following, 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 the 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 the embodiment, the connection portions 27 and 28 are formed in the same number as the first spokes 24 and the second spokes 25, respectively. That is, the housing 20 has four connection portions 27A to 27D and four connection portions 28A to 28D. Note that the connection portions 27 and the connection portions 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, in the circumferential direction, first spoke 24B branching off from protrusion 26B is connected to connection portion 27B, first spoke 24D branching off from protrusion 26D is connected to connection portion 27D, second spoke 25B is connected to connection portion 28B, and second spoke 25D is connected to connection portion 28D.

[0047] 8, the two portions 27A and 28A of the frame 22 are 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 portion 27A and the connection portion 28A. An opening Gv is formed in the circumferential direction between the connection portion 27A and the connection portion 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] Further, 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 protruding portion 26A. Similarly, through holes 29B to 29D are formed in the protruding portions 26B to 26D, respectively. Screws or the like for fixing other devices such as the arm (not shown) of a drone are inserted into 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 the other devices can be fixed 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 connecting portions 27A to 27D and 28A to 28D. The through hole 29y is provided to fix a cable k or the like connected to the motor 1. A cable fixing jig (not shown) is attached to the through hole 29y, and the cable k extending from the lower part of the motor 1 is fixed. The through holes 29A to 29D shown in FIG. 8 may be formed to adjust the rigidity of the protruding portions 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 likely to receive loads. In the 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] Also, as shown in Fig. 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 cannot be seen.

[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 weight of the housing 20 can be reduced by decreasing the thickness on the radially outer side. In addition, the load applied to the spokes 23 is distributed by curving the spokes 23 in the axial direction.

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

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

[0055] Moreover, the motor 1 in the 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. In the radial direction, an outer peripheral surface 211 of the cylinder 21 includes a protrusion 26 extending toward the frame 22. In the radial direction, two spokes 24, 25 branch off from the protrusion 26 and extend toward the frame 22. In the circumferential direction, the two spokes 24, 25 are connected to two portions 27, 28 of the frame 22, and the two portions 27, 28 of the frame are located at different positions from each other in the circumferential direction. With this configuration, the weight of the motor can be reduced.

[0056] [Variations] Although the configuration in the embodiment has been described above, the embodiment is not limited thereto. For example, the cover 10 and the housing 20 can be implemented separately, the cover 10 in the embodiment may be combined with a housing having a different shape, and the housing 20 in the embodiment may be combined with a cover having a different 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 thereto and may be formed so that, for example, T3>T2. 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 thereto and may have a shape in which only one of them is curved.

[0058] Although the present invention has been described above based on the embodiment and each modification, it goes without saying that the present invention is not limited to the embodiment and each modification, and various modifications are possible within the scope of the gist of the present invention. Such modifications that do not depart from the scope of the gist 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. [Explanation of symbols]

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

Claims

1. a cover including a tube, an annular frame surrounding the tube, and a plurality of spokes connecting the tube and the annular frame; a rotor attached to the cover; In a radial direction, two spokes of the plurality of spokes extend from the tube toward the frame, A portion of the frame is connected to the two spokes. Motor.

2. A stator is provided. The spokes are curved so as to be convex from the stator side toward the cylinder. The motor according to claim 1 .

3. Two of the spokes extend from the frame toward a portion of the barrel, a portion of the frame includes an engaged portion that engages with a portion of the rotor; 3. The motor according to claim 1 or 2.

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

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