Motor

Abstract

To provide a motor which can be easily assembled.SOLUTION: A motor 1 comprises a rotor 30 comprising a housing 31 having an opening 39, a yoke 32, and a plate 40 covering the opening 39 of the housing 31. The plate 40 comprises one or more projections 47, 48 extending in a radial direction, and the yoke 32 is supported by the housing 31 in a rotational axis direction. The projections 47, 48 contact the housing 31 and / or the yoke 32 in the rotational axis direction.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] For example, Patent Document 1 discloses a motor for a drone. In this motor, an opening formed in a top plate is covered with a punching plate. This punching plate can prevent dust from entering the motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-86311 A Summary of the Invention [Problem to be solved by the invention]

[0004] The punching plate is attached to the tabletop by engaging with a crimped portion formed on the underside of the tabletop. This requires bending part of the cylindrical portion formed on the underside of the tabletop in the radial direction, which makes the installation of the plate time-consuming.

[0005] Therefore, an object of the present invention is to provide a motor that can be easily assembled. [Means for solving the problem]

[0006] A motor according to one embodiment of the present invention comprises a rotor having a housing with an opening, a yoke, and a plate covering the opening of the housing, the plate having one or more radially extending protrusions, the yoke being supported by the housing in the direction of rotational axis, and the protrusions contacting the housing and / or the yoke in the direction of rotational axis. [Brief description of the drawings]

[0007] [Figure 1] 1 is a perspective view showing a schematic structure of a motor 1 according to an embodiment of the present invention. [Diagram 2] 2 is a cross-sectional view of the motor 1 taken along line 2-2 in FIG. [Diagram 3] 2 is a partially enlarged perspective view showing the schematic structure of a housing 31 and a yoke 32. FIG. [Figure 4] FIG. 2 is a plan view showing a schematic structure of a plate 40 according to one specific example. [Diagram 5] 2 is a partially enlarged perspective cross-sectional view taken along line 2-2 of FIG. 1. [Figure 6] 6 is a partially enlarged perspective cross-sectional view taken along line 6-6 in FIG. 1. [Figure 7] FIG. 2 is a partially enlarged perspective view of a housing 31 alone, illustrating the structure of the housing 31 according to one specific example. [Figure 8] FIG. 11 is a perspective view showing a schematic structure of a motor 1A according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view showing a schematic structure of a motor 1 according to an embodiment of the present invention. FIG. 1 is a perspective view showing the appearance of the motor 1 as seen from one side, that is, the upper side, in a direction (hereinafter referred to as the "rotation axis direction") along a rotation axis (hereinafter referred to as simply the "axis") x constituting the rotation axis of the motor 1. FIG. 2 is a cross-sectional view of the motor 1 taken along line 2-2 in FIG. 1. This cross-sectional view is a vertical cross-sectional view of the motor 1 taken along an imaginary plane including the axis x. The motor 1 is a motor incorporated in a propulsion device of an unmanned aircraft such as a drone.

[0009] In the following description of this embodiment, one side in the direction of the rotation axis is defined as the upper side, and the other side opposite the one side is defined as the lower side. The upper and lower sides do not necessarily correspond to the up-down relationship in the direction of gravity. Furthermore, the radial direction of the motor 1 is defined in a direction perpendicular to the axis x. In this radial direction, the side away from the axis x is defined as the outer circumferential side, while the direction approaching the axis x is defined as the inner circumferential side. Furthermore, the circumferential direction of the motor 1 is defined around the axis x. In this circumferential direction, clockwise and counterclockwise are defined around the axis x when the motor 1 is viewed from above.

[0010] As shown in Fig. 2, the motor 1 includes a stator 10 and a rotor 30 rotatably supported by the stator 10. The stator 10 includes a holder 11. The holder 11 includes a cylindrical portion (hereinafter referred to as the "inner portion") 12 on the inner periphery side, a cylindrical portion (hereinafter referred to as the "outer portion") 13 arranged on the outer periphery side of the inner periphery 12, and a portion (hereinafter referred to as the "connection portion") 14 that connects the lower ends of the inner periphery 12 and the outer periphery 13 to each other. The holder 11 is integrally formed from, for example, a resin material or a metal material.

[0011] The inner peripheral portion 12 and the outer peripheral portion 13 are formed in a cylindrical shape centered on the axis x. As a result, an annular space is formed between the cylindrical outer peripheral surface of the inner peripheral portion 12 and the cylindrical inner peripheral surface of the outer peripheral portion 13. The connection portion 14 is formed in an annular flat plate shape along an imaginary plane perpendicular to the axis x. A circular opening 12a is formed at the lower end of the inner peripheral portion 12. The stator 10 has a flat circular cover 15 that closes this opening 12a. The holder 11 is attached to the arm of the drone or the like by fastening parts (not shown) such as bolts. In this manner, the stator 10, i.e., the motor 1, is attached to the arm of the drone or the like.

[0012] The stator 10 has a stator core 16, a coil 17, and an insulator 18. The stator core 16 is attached to the cylindrical outer circumferential surface of the outer circumferential portion 13 of the holder 11. The stator core 16 is formed from a laminate of magnetic material such as silicon steel plates. The stator core 16 functions as a yoke for the stator 10. The stator core 16 has, for example, a cylindrical portion on the inner circumferential side, and a plurality of teeth each extending radially from the outer circumferential surface of this cylindrical portion (neither is shown). A coil 17 is wound around each tooth. The insulator 18 is an insulating material. The insulator 18 provides insulation between the stator core 16 and the coil 17.

[0013] Two bearings 20, 21 are attached to the cylindrical inner peripheral surface of the inner peripheral portion 12 of the holder 11 along the rotation axis direction. The bearings 20, 21 are, for example, ball bearings. The outer rings of the bearings 20, 21 are attached to the cylindrical inner peripheral surface of the inner peripheral portion 12 by, for example, press fitting, clearance fit, or the like. The above-mentioned rotor 30 is attached to the inner rings of the bearings 20, 21. In this way, the rotor 30 is rotatably supported by the stator 10 via the bearings 20, 21. Returning to Figs. 1 and 2, in this example, the rotor 30 has a housing 31 supported by the bearings 20, 21, a yoke 32 supported by the housing 31, and a magnet 33 attached to the yoke 32.

[0014] The housing 31 has an inner cylindrical tube (hereinafter referred to as the "inner cylindrical portion") 34, an outer cylindrical tube (hereinafter referred to as the "outer cylindrical portion") 35, a portion (hereinafter referred to as the "mounting portion") 36 for mounting a propeller (not shown), an annular frame 37 surrounding the outer cylindrical portion 35 in the radial direction, and a plurality of spokes 38 connecting the outer cylindrical portion 35, the mounting portion 36, and the frame 37 to one another. The inner cylindrical portion 34, the outer cylindrical portion 35, and the frame 37 are all formed in an annular shape centered on the axis x. The inner cylindrical portion 34, the outer cylindrical portion 35, the mounting portion 36, and the frame 37 are integrally formed from, for example, a resin material or a metal material.

[0015] The mounting portion 36 is formed, for example, in a flat cylindrical shape. A propeller (not shown) of the propulsion device is attached to the mounting portion 36 by fastening parts such as bolts. The inner cylinder portion 34 protrudes downward from the mounting portion 36 along the rotation axis direction. A part of the inner cylinder portion 34 is accommodated in the inner peripheral portion 12 of the holder 11. The outer rings of the bearings 20, 21 are attached to the outer peripheral surface of the inner cylinder portion 34 by, for example, press fitting, clearance fit, or the like. The outer cylinder portion 35 is arranged on the outer peripheral side of the inner cylinder portion 34. A part of the outer cylinder portion 35 is accommodated in the space between the inner peripheral portion 12 and the outer peripheral portion 13 of the holder 11. The frame 37 is arranged, for example, on the outer peripheral portion of the housing 31, particularly at the end of the outer peripheral portion in the radial direction, and extends continuously and uninterrupted in the circumferential direction around the axis x.

[0016] For example, six spokes 38 are arranged at equal angular intervals (60 degrees) around the axis x in the circumferential direction. Each spoke 38 extends radially to connect the outer cylinder portion 35 and the frame 37 to each other. In this example, as is clear from FIG. 2, the multiple spokes 38 extend along an imaginary plane perpendicular to the axis x. Thus, in the housing 31, one opening 39 is formed between two circumferentially adjacent spokes 38, 38, for a total of six openings 39. The rotor 30 has a plate 40 that covers all the openings 39 of the housing 31. In this example, the plate 40 is arranged along the lower surface 31a of the housing 31. The structure of the plate 40 will be described in detail later.

[0017] The yoke 32 is supported by a frame 37 of the housing 31 in the rotation axis direction. The yoke 32 is formed of, for example, a magnetic material. FIG. 3 is a partially enlarged perspective view showing a schematic structure of the housing 31 and the yoke 32. Referring to FIGS. 1 to 3 together, the yoke 32 has a cylindrical main body 41. A cylindrical magnet 33 is fixed to the inner peripheral surface of the main body 41 of the yoke 32. The magnet 33 is formed of, for example, a permanent magnet. The magnet 33 may be a single cylindrical permanent magnet, or may be formed of a plurality of permanent magnets connected in the circumferential direction and arranged in a cylindrical shape.

[0018] The yoke 32 has one or more recesses 42 formed on an upper edge 41a of a main body 41, and two protrusions 43, 43 extending upward in the direction of the rotation axis from a bottom (hereinafter referred to as a "bottom edge") 42a of each recess 42. In this example, six recesses 42 are formed in the circumferential direction on the upper edge 41a of the main body 41 corresponding to the outer circumferential side of the spokes 38. In this example, the upper end (hereinafter referred to as an "upper edge") 41a of the main body 41 is defined along an imaginary plane perpendicular to the axis x. The recesses 42 are recessed downward in the direction of the rotation axis from the upper edge 41a of the main body 41. The bottom edge 42a of the recesses 42 is defined along an imaginary plane perpendicular to the axis x, similar to the upper edge 41a of the main body 41.

[0019] The upper edge 41a of the main body 41 is set at approximately the same position as the upper surface 37a of the frame 37 in the rotation axis direction. The protruding portion 43 extends from the bottom edge 42a of the recess 42 upward in the rotation axis direction beyond the upper edge 41a of the main body 41. The upper end of the protruding portion 43 is bent radially inward. By bending the protruding portion 43 inward in this manner, the protruding portion 43 is crimped to the frame 37. As a result, the yoke 32 is supported by the frame 37 of the housing 31. In addition, a convex portion 37c that protrudes outward is formed on the outer peripheral surface 37b of the frame 37. In this example, the convex portion 37c extends long in the circumferential direction. The convex portion 37c enters the recess 42 between the two protruding portions 43, 43.

[0020] FIG. 4 is a plan view showing a schematic structure of a plate 40 according to a specific example. The plate 40 has a main body 45 formed of, for example, an annular flat plate, a plurality of through holes 46 formed in the main body 45, and one or a plurality of protrusions 47, 48 extending radially from the main body 45. The through holes 46 are defined, for example, as a circle in a plan view. The through holes 46 are arranged at equal intervals in the main body 45. The main body 45 has a circular outer peripheral portion 45a formed on the outer peripheral side and a circular inner peripheral portion 45b formed on the inner peripheral side. The size (diameter) of the outer peripheral portion 45a is approximately equal to the size (diameter) of the outer peripheral surface of the frame 37. The size (diameter) of the inner peripheral portion 45b is approximately equal to the size (diameter) of the outer peripheral surface of the outer cylinder portion 35.

[0021] In this example, the plate 40 has a plurality of first protrusions 47 extending from the outer periphery 45a to the outer periphery side, and a plurality of second protrusions 48 extending from the inner periphery 45b to the inner periphery side. The main body 45, the first protrusions 47, and the second protrusions 48 are all formed, for example, along the same plane. In this example, for example, six first protrusions 47 are formed at equal angular intervals (60 degrees) in the circumferential direction around the axis x. The six first protrusions 47 are formed corresponding to the positions of the spokes 38 of the housing 31. Meanwhile, for example, six second protrusions 48 are formed at equal angular intervals (60 degrees) in the circumferential direction around the axis x. The six first protrusions 47 are offset from the six second protrusions 48 by an angle of 30 degrees around the axis x. That is, one first protrusion 47 is disposed at a circumferential intermediate position between two second protrusions 48, 48 adjacent to each other around the axis x. In other words, one second protrusion 48 is disposed at a midpoint in the circumferential direction between two first protrusions 47, 47 adjacent to each other around the axis x.

[0022] Each first protrusion 47 has three protrusions 47a, 47b, 47c arranged in the circumferential direction. Each of the protrusions 47a, 47b, 47c has a generally rectangular contour in plan view. In the circumferential direction, the central protrusion 47b has a length greater than the protrusions 47a, 47c. In the circumferential direction, the protrusions 47a, 47c have the same length. In the radial direction, the protrusions 47a, 47b, 47c have one end and the other end extending in the radial direction. In the circumferential direction, the length from one end of the protrusion 47a to the other end of the protrusion 47c is smaller than the length of the bottom edge 42a of the recess 42 of the yoke 32. On the other hand, each of the second protrusions 48 has a generally arc-shaped contour that bulges convexly toward the inner circumferential side in plan view. The plate 40 is integrally formed from, for example, a metal material or a resin material.

[0023] FIG. 5 is a partially enlarged perspective cross-sectional view of a cross section taken along line 2-2 in FIG. 1. In particular, referring to FIG. 3 and FIG. 5 together, the plate 40 is disposed along the lower surface 31a of the housing 31. The first convex portion 47 of the plate 40 is accommodated in the recess 42 of the yoke 32. Specifically, the protruding portion 43 is disposed between the convex pieces 47a and 47b of the first convex portion 47 and between the convex pieces 47b and 47c. In this manner, the convex pieces 47a, 47b, and 47c of the first convex portion 47 are supported by the bottom edge 42a of the recess 42. The convex piece 47b is sandwiched between the convex portion 37c of the outer peripheral surface 37b of the frame 37 and the bottom edge 42a of the recess 42 of the yoke 32. The size (diameter) of the outer periphery of the convex pieces 47a, 47b, and 47c is formed to be smaller than the size (diameter) of the outer periphery of the main body 41 of the yoke 32. That is, the outer peripheral ends of the protruding pieces 47a, 47b, and 47c are disposed on the inner side than the outer peripheral surface of the yoke 32 in the radial direction.

[0024] FIG. 6 is a partially enlarged perspective cross-sectional view taken along line 6-6 in FIG. 1. FIG. 7 is a partially enlarged perspective view of the housing 31, which shows a structure of the housing 31 according to a specific example. Referring to both FIG. 6 and FIG. 7, one or more recesses 50 recessed from the outer circumferential surface of the outer tubular portion 35 to the inner circumferential side are formed at the upper end of the outer tubular portion 35 between two circumferentially adjacent spokes 38. The recesses 50 are disposed below the lower surface of the spokes 38 facing the surface of the plate 40 in the rotation axis direction. In this example, a total of six recesses 50 are formed between every two adjacent spokes 38. The inner circumferential side portions of the recesses 50 form the inner circumferential side portions of the opening 39. Each recess 50 is offset from the spoke 38 by an angle of 30 degrees around the axis x.

[0025] The recess 50 forms a surface (hereinafter referred to as a "support surface") 51 extending along a virtual plane perpendicular to the axis x between two adjacent spokes 38, 38 at the upper end of the outer cylinder portion 35. In a plan view, the shape of the support surface 51 almost matches the contour of the second protrusion 48 of the plate 40. The depth of the recess 50 in the rotation axis direction is set to be larger than the thickness of the plate 40 in the rotation axis direction. As described above, in the circumferential direction around the axis x, the position of the recess 50 is disposed away (offset) from the position of the recess 42 by 30 degrees in the circumferential direction. Therefore, when the first protrusion 47 is disposed in the recess 42, the second protrusion 48 is disposed in the recess 50. In this way, the second protrusion 48 is supported on the support surface 51 of the recess 50 as shown in FIG. 6.

[0026] Here, the assembly method of the rotor 30 will be described below. In the assembly, the plate 40 is attached to the housing 31. With the first protrusions 47 of the plate 40 and the spokes 38 aligned in the circumferential direction, the outer cylinder portion 35 of the housing 31 is received into the inner circumferential portion 45b of the main body 45 of the plate 40. As the inner circumferential portion 45b receives the outer cylinder portion 35, the second protrusions 48 of the main body 45 slide on the outer circumferential surface of the outer cylinder portion 35. When the plate 40 reaches the upper end of the outer cylinder portion 35, the second protrusions 48 of the plate 40 engage with the recesses 50 of the outer cylinder portion 35. The second protrusions 48 are supported on the support surface 51 of the outer cylinder portion 35. In this way, the second protrusions 48 come into contact with the housing 31, that is, are supported by the housing 31. The main body 45 comes into contact with the lower surface 31a of the housing 31.

[0027] Then, the yoke 32 is attached to the housing 31. When attached, the protruding portion 43 of the yoke 32 is not bent and protrudes flatly upward. Each pair of protruding portions 43, 43 is aligned with the protruding pieces 47a, 47b, 47c of the first protruding portion 47 of the plate 40. The first protruding portion 47 of the plate 40 is supported by the bottom edge 42a of the recessed portion 42 of the main body 41 of the yoke 32. In this manner, the protruding piece 47b of the first protruding portion 47 is sandwiched between the protruding portion 37c of the frame 37 of the housing 31 and the bottom edge 42a of the recessed portion 42 of the yoke 32. In this state, the upper ends of the protruding portions 43, 43 are bent inward toward the frame 37 of the housing 31. The yoke 32 is attached to the housing 31 by crimping. At the same time, the first protruding portion 47 comes into contact with the housing 31 and the yoke 32, that is, is supported by the housing 31 and the yoke 32.

[0028] In the motor 1 as described above, the plate 40 covers the opening 39 of the housing 31 to prevent dust from entering the motor 1. The plate 40 is sandwiched between the protrusion 37c of the housing 31 and the bottom edge 42a of the recess 42 of the yoke 32 by the first protrusion 47 of the outer peripheral portion 45a in the rotation axis direction. At the same time, the plate 40 is supported by the support surface 51 of the recess 50 of the outer cylindrical portion 35 of the housing 31 in the rotation axis direction by the second protrusion 48 of the inner peripheral portion 45b. The plate 40 is easily attached to the housing 31 by inserting the outer cylindrical portion 35 into the inner peripheral portion 45b, and the motor 1 can be easily assembled. Moreover, since the first protrusion 47 and the second protrusion 48 extend radially from the main body 45, an increase in the thickness of the motor 1 in the rotation axis direction can be avoided.

[0029] In addition, the recess 50 of the outer cylinder portion 35 of the housing 31 is continuous with the opening 39 in the rotation axis direction. Therefore, for example, when molding the housing 31, the housing 31 can be punched out without the need for a slide or the like. Even when the housing 31 is manufactured by cutting instead of molding, it is not necessary to add the recess 50 by post-processing. As a result, the housing 31 can be easily manufactured. On the other hand, it is not necessary to add a new structure for supporting the first protrusion 47 to the frame 37 of the housing 31 or the recess 42 of the yoke 32. In addition, since the first protrusion 47 is accommodated in the recess 42 of the yoke 32 and the second protrusion 48 is accommodated in the recess 50 of the outer cylinder portion 35, it is possible to reliably prevent the plate 40 from rotating around the axis x.

[0030] FIG. 8 is a perspective view showing a schematic structure of a motor 1A according to another embodiment of the present invention. In this motor 1A, a plate 40A is incorporated instead of the plate 40 described above. In this plate 40A, the through hole 46 is not formed in the main body 45. Therefore, the plate 40A can reliably prevent dust and the like from entering the internal space of the motor 1A. Since the other configurations of the plate 40A are the same as those of the plate 40, the same reference numerals are used for the same configurations, and duplicated explanations will be omitted here. Since such a plate 40A is formed from a thin plate, the weight of the housing 31, i.e., the motor 1A, can be reduced compared to a case in which the opening 39 is eliminated from the housing 31.

[0031] In the motor 1, 1A as described above, one of the first convex portion 47 and the second convex portion 48 of the plate 40, 40A may be omitted. That is, the plate 40, 40A may be supported by contacting either the first convex portion 47 or the second convex portion 48 with the housing 31 and / or the yoke 32. When the plate 40, 40A is supported only by the first convex portion 47, the recess 50, i.e., the support surface 51, may not be formed on the outer peripheral surface of the outer cylinder portion 35 of the housing 31. In the above-mentioned example, the plate 40, 40A has six first convex portions 47 and second convex portions 48 formed in the circumferential direction, but the number of first convex portions 47 and second convex portions 48 less than six may be formed.

[0032] Although the present invention has been described above through the above embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear to those skilled in the art that various modifications or improvements can be made to the above embodiments. It is clear from the claims that such modifications or improvements can also be included in the technical scope of the present invention.

[0033] The above-described embodiments are intended to facilitate understanding of the present invention, and are not intended to limit the present invention. The components of the above-described embodiments, as well as their arrangements, materials, conditions, shapes, sizes, etc., are not limited to those illustrated, and can be modified as appropriate. Furthermore, components shown in different embodiments can be partially substituted or combined with each other within the scope of technical inconsistency. [Explanation of symbols]

[0034] 1, 1A motor, 10 stator, 11 holder, 12 cylindrical portion (inner peripheral portion), 12a opening, 13 cylindrical portion (outer peripheral portion), 14 connecting portion (connecting portion), 15 cover, 16 stator core, 17 coil, 18 insulator, 20 bearing, 21 bearing, 30 rotor, 31 housing, 32 yoke, 33 magnet, 34 cylindrical tube (inner cylindrical portion), 35 cylindrical tube (outer cylindrical portion), 36 mounting portion (mounting portion), 37 annular frame, 37a upper surface, 37b outer peripheral surface, 37c protruding portion, 38 spokes, 39 opening, 40 plate, 41 main body, 41a upper end portion (upper edge), 42 recessed portion, 42a bottom portion (bottom edge), 43 protruding portion, 45 main body, 45a outer peripheral portion, 45b Inner circumference, 46 through hole, 47 convex portion (first convex portion), 47a convex piece, 47b convex piece, 47c convex piece, 48 convex portion (second convex portion), 50 concave portion, 51 surface (support surface), x axis (rotation axis)

Claims

1. a rotor having a housing with an opening, a yoke, and a plate covering the opening of the housing; The plate has one or more radially extending protrusions, The yoke is supported by the housing in the rotation axis direction, A motor, wherein the protrusion contacts the housing and / or the yoke in the rotation axis direction.

2. The plurality of protrusions include a first protrusion disposed on an outer periphery of the plate, The motor according to claim 1 , wherein the first protrusion is sandwiched between the housing and the yoke.

3. the housing includes a cylinder, an annular frame surrounding the cylinder, and a plurality of spokes connecting the cylinder and the annular frame; the plurality of protrusions includes a second protrusion on an inner periphery of the plate; The motor according to claim 1 , wherein the second protrusion is supported by the cylinder between two of the spokes that are adjacent in the circumferential direction.

4. The motor according to claim 3 , wherein the second protrusion is housed in the recess of the cylinder.

5. The motor according to claim 4 , wherein the recess is formed on an outer peripheral surface of the cylinder.

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