Motor

Abstract

To reduce magnet temperature rise.SOLUTION: A motor comprises a stator, a rotor that rotates relative to the stator, and a magnet that is provided on the rotor facing the stator. The magnet has a space formed at least inside it through which a heat medium can flow.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a motor.

Background Art

[0002] For example, Patent Document 1 discloses a rotating electric machine (motor) in which a stator frame for fixing a stator is formed by additive manufacturing. In such Patent Document 1, a flow path through which a refrigerant flows is formed in the stator frame. In Patent Document 1, by flowing the refrigerant through the flow path of the stator frame, it is possible to cool the stator through the stator frame.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, a magnet may be provided on the rotor of the motor. In such a motor, when the temperature of the magnet on the rotor becomes relatively high due to the heat generation of the motor, the performance of the magnet may deteriorate. For this reason, it is desired to suppress the rise in the temperature of the magnet.

[0005] Therefore, an object of the present invention is to provide a motor capable of suppressing the rise in the temperature of a magnet.

Means for Solving the Problems

[0006] In order to solve the above problems, a motor according to an embodiment of the present invention includes: a stator, a rotor that rotates relative to the stator, a magnet provided on the rotor facing the stator, and The magnet has a space inside it through which a heat medium can flow at least.

Advantages of the Invention

[0007] According to the present invention, it becomes possible to suppress an increase in the temperature of the magnet.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0009] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The specific dimensions, materials, numerical values, etc. shown in such embodiments are merely examples for facilitating the understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and the drawings, elements having substantially the same functions and configurations are denoted by the same reference numerals to omit redundant descriptions, and elements not directly related to the present invention are not shown.

[0010] FIG. 1 is an exploded view of the motor 1 according to this embodiment. The motor 1 of this embodiment includes a rotor 10 and a stator 12. In FIG. 1, a state in which the stator 12 is removed from the rotor 10 is shown. As will be described in detail later, the motor 1 is, for example, an out-run (in other words, an outer rotor) type in which the rotor 10 is disposed outside the stator 12.

[0011] The rotor 10 has a rotor body 20, a first flange 22, a rotating shaft 24, and a magnet 26. The rotor body 20 is formed in a hollow cylindrical shape. The first flange 22 is connected to one end of the cylinder in the rotor body 20. The end of the rotor body 20 opposite to the first flange 22 opens in a state where the stator 12 is removed from the rotor 10.

[0012] The first flange 22 is formed, for example, in a circular flat plate shape. The first flange 22 may be provided with a through hole 30 that penetrates at least a part of the first flange 22. By providing the through hole 30, the circulation of air between the inside and outside of the rotor 10 can be made smooth.

[0013] The rotating shaft 24 is disposed inside the rotor body 20 so as to overlap the central axis of the rotor 10. That is, the axial direction of the rotating shaft 24 is substantially equal to the axial direction of the rotor 10. One end in the axial direction of the rotating shaft 24 is connected to the first flange 22. The rotating shaft 24 and the first flange 22 are integrated with the rotor body 20 and can rotate in synchronization with the rotation of the rotor body 20.

[0014] The magnet 26 is, for example, a permanent magnet. The magnet 26 has a shape in which a ring is circumferentially divided. A plurality of magnets 26 are provided on the inner surface of the rotor main body 20 and supported by the rotor main body 20. The plurality of magnets 26 are arranged side by side in the circumferential direction of the rotor main body 20 so as to generally form a ring shape in a state of being provided on the inner surface of the rotor main body 20. Adjacent magnets 26 are separated from each other. The magnet 26 will be described in detail later.

[0015] The stator 12 has a stator main body 40, a bearing 42, a coil 44, and a second flange 46. The stator main body 40 is formed in a substantially cylindrical shape whose outer diameter is smaller than the inner diameter of the rotor main body 20.

[0016] The bearing 42 is provided at the radial center of the stator main body 40. The bearing 42 is configured such that the rotation shaft 24 of the rotor 10 can be inserted therein.

[0017] A plurality of teeth 50 protruding radially outward of the stator main body 40 are formed on the outer periphery of the stator main body 40. The coil 44 is wound around each tooth 50.

[0018] The second flange 46 is provided at one axial end of the stator main body 40. The second flange 46 supports the stator main body 40. A wiring 52 connected to the coil 44 is drawn out from the second flange 46.

[0019] The motor 1 is assembled such that the rotation shaft 24 is inserted through the bearing 42 and the stator main body 40 is housed inside the rotor main body 20. The opening at the end of the rotor main body 20 before assembly is covered by the second flange 46 after the assembly of the motor 1. After assembly, the rotor main body 20 and the stator main body 40 are positioned between the first flange 22 and the second flange 46.

[0020] In the motor 1 after assembly, the magnet 26 of the rotor 10 and the teeth 50 of the stator 12 are arranged concentrically, and the magnet 26 is arranged opposite to the teeth 50. Since the coil 44 is wound around the teeth 50 as described above, the magnet 26 is substantially arranged opposite to the coil 44. The magnet 26 and the teeth 50 are separated from each other by a short distance so as not to contact each other. The separation distance between the magnet 26 and the teeth 50 is generally uniform along the circumferential direction of the rotor.

[0021] When alternating current power is applied to the coil 44 of the stator 12, a rotating magnetic field is generated in the stator 12. The rotor 10 rotates relative to the stator 12 around the rotation axis 24 according to the rotation of the rotating magnetic field.

[0022] FIG. 2 is a perspective view showing an example of the configuration of the magnet 26. FIG. 3 is a perspective view showing an example of the configuration of the magnet 26. In the figure, the "axial direction" means the axial direction of the rotor 10, that is, the axial direction of the rotation axis 24, and the "rotation direction" in the figure means the rotation direction of the rotor 10, that is, the rotation direction of the magnet 26.

[0023] As shown in FIGS. 2 and 3, a space 60 through which a heat medium can flow is intentionally formed inside the magnet 26. The heat medium is, for example, air, but may be any fluid capable of transferring the heat inside the magnet 26. The method of forming the space 60 will be described in detail later.

[0024] As shown in FIGS. 2 and 3, the magnet 26 includes a first opening 70a and a second opening 70b. Hereinafter, the first opening 70a and the second opening 70b may be collectively referred to as the opening 70.

[0025] The first opening 70a is provided at one end face of the magnet 26 in the axial direction of the rotor 10. The second opening 70b is provided at the other end face of the magnet 26 in the axial direction of the rotor 10. The opening 70 communicates the space 60 inside the magnet 26 with the outside of the magnet 26.

[0026] As shown by the dashed arrow in FIG. 3, in the motor 1, air, which is an example of a heat medium, can be introduced from outside the magnet 26 into the space 60 inside the magnet 26 through the first opening 70a. Further, in the motor 1, air, which is an example of a heat medium, can be discharged from the space 60 inside the magnet 26 to the outside of the magnet 26 through the second opening 70b.

[0027] Thus, in the motor 1 of the present embodiment, the heat medium can flow through the space 60 inside the magnet 26. Therefore, in the motor 1 of the present embodiment, the rise in the temperature of the magnet 26 can be suppressed from the inside of the magnet 26 by the flow of the heat medium. As a result, in the motor 1 of the present embodiment, a decrease in the performance of the magnet 26 can be suppressed.

[0028] Further, in the motor 1 of the present embodiment, since the rise in the temperature of the magnet 26 can be suppressed from the inside of the magnet 26, the temperature suppression effect of the magnet 26 can be improved as compared with a mode of suppressing the rise in the temperature of the magnet 26 from the surface of the magnet 26.

[0029] Note that the present invention is not limited to the mode in which both the first opening 70a and the second opening 70b are provided. For example, only the first opening 70a may be provided. Even when there is one opening 70, since the heat medium can flow between the space 60 inside the magnet 26 and the outside through the opening 70, the temperature suppression effect of the magnet 26 can be improved as compared with a mode of suppressing the rise in the temperature of the magnet 26 from the surface of the magnet 26.

[0030] Further, the position of the opening 70 is not limited to the end face in the axial direction of the rotor 10 in the magnet 26. For example, in a mode in which adjacent magnets 26 are arranged at intervals, the opening 70 may be provided on the end face in the circumferential direction of the magnet 26. Also in this example, the heat medium can move between the inside and the outside of the magnet 26 through the opening 70, and the rise in the temperature of the magnet 26 can be suppressed.

[0031] As shown in FIGS. 2 and 3, the magnet 26 has fins 72. The fins 72 may be made of a magnetic material as part of the magnet 26. The fins 72 are provided in the openings 70. In the examples of FIGS. 2 and 3, three fins 72 are provided in the first opening 70a, and three fins 72 are provided in the second opening 70b. Note that the number of fins 72 in one opening 70 is not limited to the illustrated number and may be set to any number.

[0032] The fins 72 are arranged to extend in a direction inclined with respect to the axial direction of the rotor 10 from the openings 70. More specifically, in the first opening 70a, the fins 72 extend so as to be inclined in a direction opposite to the rotation direction of the magnet 26 as they proceed from the end face of the first opening 70a in the magnet 26 toward the inside of the magnet 26. Also, in the second opening 70b, the fins 72 extend so as to be inclined in a direction opposite to the rotation direction of the magnet 26 as they proceed from the inside of the magnet 26 toward the end face direction of the second opening 70b in the magnet 26.

[0033] When the magnet 26 rotates in the rotation direction, the heat medium in the vicinity of the first opening 70a acts so as to be scraped from the first opening 70a toward the inside of the magnet 26 by the fins 72 of the first opening 70a. Thereby, in the motor 1, the feeding of the heat medium into the magnet 26 can be performed more smoothly.

[0034] Also, when the magnet 26 rotates in the rotation direction, the heat medium in the vicinity of the fins 72 of the second opening 70b acts so as to slide out of the magnet 26 by the fins 72 of the second opening 70b. Thereby, in the motor 1, the discharging of the heat medium from the magnet 26 can be performed more smoothly.

[0035] Also, since the surface area of the magnet 26 increases due to the provision of the fins 72, the rise in the temperature of the magnet 26 can be suppressed by the heat dissipation of the fins 72 themselves.

[0036] Note that the present invention is not limited to the aspect in which the fins 72 are provided on both the first opening 70a and the second opening 70b. For example, the fins 72 may be provided on either the first opening 70a or the second opening 70b. Even in this case, the movement of the heat medium inside and outside the magnet 26 can be smoothly performed. Further, the fins 72 may be omitted from both the first opening 70a and the second opening 70b. Further, the fins 72 may be provided so that at least a part thereof protrudes outward from the end face of the magnet 26 as in the example of the fins 72 in FIG. 7 described later.

[0037] As shown in FIG. 2, the magnet 26 has a facing surface 74 that is a surface facing the coil 44 of the stator 12. Specifically, since the motor 1 is an outer-rotor type, the facing surface 74 of the magnet 26 is an inner surface corresponding to the inner peripheral surface of the ring formed by the plurality of magnets 26.

[0038] As shown in FIG. 2, the facing surface 74 of the magnet 26 covers the space 60 inside the magnet 26. In other words, in this magnet 26, the space 60 inside the magnet 26 is not exposed on the facing surface 74, and a decrease in the density of the material of the magnet 26 on the facing surface 74 is suppressed.

[0039] Here, the facing surface 74 of the magnet 26 serves as a magnetic pole of N pole or S pole. In the motor 1, since a decrease in the density of the material is suppressed on the facing surface 74 serving as the magnetic pole, a decrease in magnetism due to the magnet 26 can be suppressed, and as a result, a decrease in the output of the motor 1 can be suppressed.

[0040] FIG. 4 is a partial enlarged view showing an example of the interior of the magnet 26 enlarged. As shown in FIG. 4, the magnet 26 has a lattice structure portion 80 inside the magnet 26. That is, the space 60 inside the magnet 26 is formed by making the internal structure of the magnet 26 a lattice structure. The lattice structure portion 80 is composed of a material having magnetism as a part of the magnet 26. Note that the lattice structure is a structure that creates a three-dimensional object by arranging branched lattices periodically. The magnet 26 having the lattice structure portion 80 may be manufactured, for example, by laminated molding, that is, 3D printing.

[0041] In the motor 1 of the present embodiment, by providing the lattice structure portion 80 inside the magnet 26, it is possible to suppress a decrease in the strength of the magnet 26, maintain the magnetism of the magnet 26, and form the space 60 inside the magnet 26.

[0042] As shown in FIG. 4, the lattice structure portion 80 may be formed by arranging body-centered cubic lattices periodically. Note that the body-centered cubic lattice is one in which nodes are arranged at each vertex and the center of a cubic unit lattice.

[0043] By adopting a body-centered cubic lattice as the lattice structure of the lattice structure portion 80, it is possible to secure the space 60 inside the magnet 26, maintain the magnetism of the magnet 26, and appropriately suppress a decrease in the strength of the magnet 26.

[0044] FIG. 5 is a partial enlarged view showing the interior of the magnet 26B of a modified example enlarged. The lattice shape in the lattice structure portion 80B shown in FIG. 5 is the same body-centered cubic lattice as in FIG. 4. However, in FIG. 5, the thickness of the line between the nodes, that is, the thickness of the lattice, is thinner than that in the example of FIG. 4.

[0045] In the lattice structure portion 80B where the lattice thickness is relatively thin, the strength inside the magnet 26B may decrease compared to the lattice structure portion 80 where the lattice thickness is relatively thick. However, the thinner the lattice thickness, the more the volume of the internal space 60 of the magnet 26B can be expanded. Then, since the heat medium can easily flow inside the magnet 26B, the temperature of the magnet 26B can be efficiently suppressed.

[0046] That is, when developing or manufacturing the motor 1, the lattice thickness of the lattice structure portion 80 may be appropriately set in consideration of the strength of the magnet 26 and the fluidity of the heat medium.

[0047] FIG. 6 is an enlarged partial view showing the inside of the magnet 26C of another modification. As shown in FIG. 6, the lattice structure portion 80C may be formed by periodically arranging orthogonal lattices. Note that the orthogonal lattice is one in which nodes are arranged at each vertex of a cubic unit lattice.

[0048] In the orthogonal lattice, compared with the body-centered cubic lattice, the number of lines between nodes in the unit lattice is small, so the strength inside the magnet 26C may decrease. However, in the orthogonal lattice, compared with the body-centered cubic lattice, the internal space 60 of the magnet 26C can be made into a linear shape. Then, by adopting the orthogonal lattice as the lattice structure, compared with the body-centered cubic lattice, the heat medium can easily flow inside the magnet 26C, so the rise in the temperature of the magnet 26 can be efficiently suppressed.

[0049] That is, when developing or manufacturing the motor 1, the lattice shape of the lattice structure portion 80 may be appropriately set in consideration of the strength of the magnet 26 and the fluidity of the heat medium.

[0050] Note that the lattice structure is not limited to the exemplified body-centered cubic lattice and orthogonal lattice, and for example, any lattice shape such as a face-centered cubic lattice may be applied.

[0051] So far, it has been described that the internal structure of the magnet 26 is a lattice structure, thereby forming the space 60 inside the magnet 26. However, not only inside the magnet 26, but for example, by configuring the entire magnet 26 with a lattice structure, the space 60 may be formed throughout the entire magnet 26. That is, the magnet 26 may be such that at least inside, a space 60 through which a heat medium can flow is formed. Also in this aspect, the rise in the temperature of the magnet 26 can be suppressed from the inside of the magnet 26 by the flow of the heat medium.

[0052] FIG. 7 is a perspective view illustrating the inside of a magnet 26D of another modification. As shown in FIG. 7, the magnet 26D has a partition plate 90 inside.

[0053] The partition plate 90 is made of a material having magnetism as a part of the magnet 26. The partition plate 90 is provided standing in the radial direction intersecting the axial direction and the rotational direction in the magnet 26D. The partition plate 90 extends in the axial direction in the magnet 26D. More specifically, the first opening 70a side of the partition plate 90 is continuous with the fins 72 of the first opening 70a. The second opening 70b side of the partition plate 90 is continuous with the fins 72 of the second opening 70b.

[0054] In the example of FIG. 7, an example in which four partition plates 90 are provided is shown, but the number of partition plates 90 is not limited to four and may be any number that can appropriately form the space 60.

[0055] The magnet 26D has a space 60 formed inside by the opposing surface 74 in the magnet 26D, the outer surface on the side opposite to the opposing surface 74, the circumferential end surfaces in the magnet 26, and the plurality of partition plates 90. The heat medium fed into the inside of the magnet 26D will be guided by the partition plates 90 and moved in the axial direction. Also in the magnet 26D of this modification, the rise in the temperature of the magnet 26D can be suppressed from the inside of the magnet 26D.

[0056] Thus, the internal structure of the magnet 26 is not limited to the lattice structure, and for example, it may have a structure using the partition plate 90 as shown in FIG. 7, as long as it is a structure that allows the heat medium to appropriately flow inside the magnet 26.

[0057] FIG. 8 is a perspective view of the magnet 26E of another modification as viewed from the outer peripheral surface 100 side. FIG. 9 is a perspective view of the magnet 26E of another modification as viewed from the opposing surface 74 side. FIG. 10 is a cross-sectional view of the magnet 26E of another modification. In FIG. 10, for the sake of convenience, the lattice structure portion 80 is simply shown by cross-hatching. Also, the dashed-dotted line C1 in FIG. 10 indicates the central axis of the rotor 10.

[0058] As shown in FIGS. 8 to 10, the magnet 26E includes an outlet-side opening 70c and an inlet-side opening 70d as openings 70 that communicate the internal space 60 of the magnet 26E with the outside.

[0059] The outlet-side opening 70c is provided on the outer surface in the radial direction intersecting the axial direction of the rotor 10 in the magnet 26E, that is, on the outer peripheral surface 100. The outer peripheral surface 100 is the surface on the side opposite to the opposing surface 74. The outlet-side opening 70c is provided, for example, at one end in the axial direction of the magnet 26E.

[0060] The inlet-side opening 70d is provided independently of the outlet-side opening 70c in the magnet 26E. More specifically, the inlet-side opening 70d is provided on the opposing surface 74 of the magnet 26E. The inlet-side opening 70d is provided, for example, at the other end in the axial direction of the magnet 26E.

[0061] Note that the inlet-side opening 70d is not limited to the mode of being provided on the opposing surface 74, and as long as it is independent of the outlet-side opening 70c, it may be provided at an arbitrary position, such as the end face in the axial direction of the magnet 26E.

[0062] Fins 72 are provided inside the outlet-side opening 70c and inside the inlet-side opening 70d. The fins 72 straighten the flow of the heat medium through the outlet-side opening 70c and the flow of the heat medium through the inlet-side opening 70d. Also, the temperature rise of the magnet 26E can be suppressed by the heat dissipation of the fins 72 themselves. Note that the fins 72 may be omitted.

[0063] In addition, a communication hole 110 continuous with the outlet-side opening 70c is provided in a portion of the rotor body 20 corresponding to the outlet-side opening 70c of the magnet 26E. The communication hole 110 penetrates the rotor body 20 and communicates the outside of the rotor body 20 with the outlet-side opening 70c.

[0064] When the rotation of the rotor 10 stops, a heat medium such as air stays inside the magnet 26E. When the rotation of the rotor 10 starts, as the magnet 26E is rotated in the circumferential direction, a centrifugal force related to the rotational angular velocity of the magnet 26E and the self-weight of the heat medium is applied to the heat medium staying inside the magnet 26E.

[0065] Since the outlet-side opening 70c is provided on the outer peripheral surface 100 of the magnet 26E, the heat medium to which the centrifugal force is applied acts so as to be sent radially outward from the outlet-side opening 70c. Thereby, the heat medium inside the magnet 26E is sent out of the magnet 26E through the outlet-side opening 70c and is sent out of the rotor body 20 through the communication hole 110.

[0066] When the heat medium inside the magnet 26E is sent out from the outlet-side opening 70c, the inside of the heat medium becomes negative pressure. Then, the heat medium is sucked into the magnet 26E through the inlet-side opening 70d.

[0067] In this way, in the magnet 26E, the heat medium flows inside the magnet 26E. Therefore, also in the magnet 26E of this modification example, the temperature rise of the magnet 26E can be suppressed from the inside of the magnet 26E.

[0068] FIG. 11 is a perspective view showing an example of the configuration of the rotor 210 of the motor 200 according to the modified example. In the motor 200, for convenience, the description and explanation of the stator are omitted. The motor 200 is of an inner rotor type in which the rotor 210 is disposed inside with respect to the stator.

[0069] The rotor 210 has a rotor body 220, a rotating shaft 224, and magnets 226. The rotor body 220 is formed in a cylindrical shape. The rotating shaft 224 is fitted into the rotor body 220. The magnets 226 are provided on the outer peripheral surface of the rotor body 220.

[0070] The magnet 226 has a lattice structure portion 230 and an opening 232. The lattice structure portion 230 is provided inside the magnet 226. In the magnet 226, a space 234 is formed inside the magnet 226 by the lattice structure portion 230. The opening 232 is provided on the end surface in the axial direction of the rotor 210 and communicates the space 234 inside the magnet 226 with the outside.

[0071] Also in the motor 200 having this rotor 210, a heat medium can flow inside the magnet 226. Therefore, also in the motor 200, the rise in the temperature of the magnet 226 can be suppressed from the inside of the magnet 226.

[0072] Thus, in either the outer rotor type or the inner rotor type motors 1 and 200, it is possible to suppress the rise in the temperature of the magnets 26 and 226.

[0073] Note that each of the modified examples exemplified in the outer rotor type may be appropriately applied to the inner rotor type as shown in FIG. 11.

[0074] As described above, the embodiments of the present invention have been described with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such embodiments. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope described in the claims, and it is naturally understood that they also belong to the technical scope of the present invention.

Description of Symbols

[0075] 1. 200 Motor 12 Stator 10, 210 Rotor 26, 26B, 26C, 26D, 26E, 226 Magnet 60, 234 Space 74 Opposite Surface 70, 232 Opening 72 Fin 70a First Opening 70b Second Opening 70c Outlet - side Opening 70d Inlet - side Opening

Claims

1. A stator, a rotor that rotates relative to the stator, and a magnet provided on the rotor facing the stator, characterized in that, the magnet has a space inside thereof through which a heat medium can flow, the motor.

2. The motor according to claim 1, wherein the space in the magnet is formed by making at least an internal structure of the magnet a lattice structure.

3. The magnet has, a facing surface facing the stator and covering the space inside the magnet, and an opening for communicating the space inside the magnet with the outside, the motor according to claim 1.

4. The magnet further has fins, the opening is provided at an end face in the axial direction of the rotor in the magnet, the fins are arranged to extend in a direction inclined with respect to the axial direction of the rotor from the opening, the motor according to claim 3.

5. The opening has, an outlet-side opening provided on an outer surface in the radial direction intersecting the axial direction of the rotor in the magnet, and an inlet-side opening provided independently of the outlet-side opening in the magnet, the motor according to claim 3.

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