motor

Abstract

A motor (1) comprises: a rotor (20) having a yoke (30), a first magnet (41), and a second magnet (42) facing the first magnet (41); and a stator (10). The yoke (30) comprises a hole (38) and a frame (39) surrounding the hole (38). The first magnet (41) is disposed in the hole (38) of the yoke (30), and the second magnet (42) comprises a first surface (4a) facing the frame (38) of the yoke (30) in the circumferential direction and a second surface (4b) facing the stator (10) in the radial direction.

Description

[Technical Field]

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

[0002] Halbach-array motors are known, in which multiple magnets with different magnetic flux directions are arranged on the surface of a rotor yoke. For example, in Halbach-array motors with an inner rotor structure, a technique is known in which the magnets are embedded in a magnet holding member to prevent the magnets from popping out due to centrifugal force during rotation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-006545 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-207067 [Patent Document 3] International Publication No. 2014 / 115655 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a Halbach array motor, the amount of magnetic flux flowing from the magnet to the stator may decrease, resulting in a decrease in the motor's output torque.

[0005] One object of the present invention is to provide a motor capable of improving output torque. [Means for solving the problem]

[0006] In one embodiment, the motor ,B The rotor includes a motor and a stator. The rotor has a yoke, a plurality of first magnets, a second magnet facing the first magnets via the yoke, and a third magnet. The yoke is Multiple The hole and the Multiple Surrounding the hole Multipleand a frame. Multiple The first magnet is Multiple placed in the hole The second magnet and the third magnet are disposed between a first frame and a second frame that are adjacent to each other in the circumferential direction among the plurality of frames. The second magnet is arranged so as to be in contact with the yoke in the circumferential direction. No. 1 The rotor has a first surface facing the frame and a second surface facing the stator in the radial direction. The third magnet has a first surface facing the second frame of the yoke in the circumferential direction and a second surface facing the stator in the radial direction, and the second surface of the second magnet and the second surface of the third magnet form the outer circumferential surface or the inner circumferential surface of the rotor.

[0007] According to one aspect, the output torque can be improved. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing an example of a motor according to an embodiment. [Figure 2] FIG. 2 is an exploded perspective view showing an example of a motor according to an embodiment. [Figure 3] FIG. 3 is an enlarged perspective view showing an example of a motor according to an embodiment. [Figure 4] FIG. 4 is an enlarged top view showing an example of a motor according to an embodiment. [Figure 5] FIG. 5 is an enlarged perspective view showing an example of a rotor from which a magnet has been removed in an embodiment. [Figure 6] FIG. 6 is an enlarged perspective view showing an example of a rotor in the embodiment. [Figure 7] FIG. 7 is an enlarged top view showing an example of a rotor in the first modified example. [Figure 8] FIG. 8 is a perspective view showing an example of a motor according to the second modified example. [Figure 9] FIG. 9 is an enlarged perspective view showing an example of a motor according to the second modified example. [Figure 10] FIG. 10 is an enlarged top view showing an example of a rotor in the third modified example. [Figure 11] FIG. 11 is an enlarged top view showing an example of a rotor in the fourth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the motor disclosed herein will be described in detail with reference to the drawings. Note that the dimensional relationships and ratios of elements in the drawings may differ from reality. The dimensional relationships and ratios may also differ between the drawings. To facilitate understanding of the description, each drawing may illustrate a coordinate system in which the direction in which the motor's rotation shaft extends is the axial direction.

[0010] [Embodiment] First, a motor according to an embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective view showing an example of a motor according to an embodiment. FIG. 2 is an exploded perspective view showing an example of a motor according to an embodiment. As shown in FIG. 1, the motor 1 according to the embodiment includes a stator 10 and a rotor 20. The motor 1 according to the embodiment is a so-called flat motor in which, for example, the length in the radial direction of the stator core is greater than the length in the axial direction. The motor 1 is housed, for example, in a frame (not shown), and transmits driving force to the outside via a rotating shaft (not shown).

[0011] As shown in FIG. 2, the stator 10 includes a stator core 11, insulators 12, and coils 13. The stator core 11 is formed by stacking a plurality of plate-shaped metal members or magnetic materials, such as silicon steel sheets, electromagnetic steel sheets, or soft magnetic steel sheets, in the axial direction. The insulators 12 are formed of an insulating material, such as resin, and are attached to the stator core 11 from the positive and negative axial sides. The coils 13 are wound around the stator core 11 via the insulators 12. As shown in FIG. 2, ends 14 of conductor wires are drawn out from the coils 13 in the same direction (the positive axial side) as lead wires. The ends 14 of the conductor wires are used, for example, as terminals of the coils 13.

[0012] As shown in FIGS. 1 and 2, the rotor 20 is disposed radially inside the stator 10. That is, the motor 1 in this embodiment is an inner rotor type motor. As shown in FIG. 2, the rotor 20 includes a yoke 30 that forms a magnetic path, a plurality of first magnets 41, a plurality of second magnets 42, and a plurality of third magnets 43. In the following description, the first magnets 41 to the third magnets 43 may be referred to as magnets 40 when there is no need to distinguish between them. Furthermore, the first magnet 41 may be referred to as a main magnet, and the second magnet 42 and the third magnet 43 may be referred to as auxiliary magnets. In this embodiment, two types of auxiliary magnets 42 and 43 are disposed for one main magnet 41.

[0013] The yoke 30 is a yoke made of, for example, iron, and includes an annular portion 36, a hole 38, and a frame 39 surrounding the hole 38. The yoke 30 includes a plurality of holes 38 and a plurality of frames 39. As shown in FIG. 2, the annular portion 36 extends in the circumferential direction, and the plurality of frames 39 are formed, for example, aligned at equal intervals in the circumferential direction. Note that in the following embodiments and modifications, the material of the yoke is not limited to iron, and may be other magnetic materials.

[0014] The first magnet 41 is disposed in a hole 38 surrounded by a frame 39, and the second magnet 42 and the third magnet 43 are disposed between two adjacent frames 39 in the circumferential direction. In the embodiment, two auxiliary magnets 42 and 43 are disposed between two adjacent frames 39 in the circumferential direction.

[0015] In the embodiment, the second magnet 42 and the third magnet 43 have substantially the same shape, but have different magnetic flux directions, as will be described later. The second magnet 42 and the third magnet 43 are arranged to be symmetrical with respect to the axis of symmetry, which is a line L1 connecting the circumferential center of the first magnet 41 and the center of the rotor 20, as shown in FIG. 4. FIG. 3 is an enlarged perspective view showing an example of a motor in the embodiment. FIG. 4 is an enlarged top view showing an example of a motor. FIGS. 3 and 4 are enlarged views of a portion indicated by a frame F1 in FIG. 1. Note that FIG. 4 illustrates a simplified version of the stator 10.

[0016] 3 and 4, a magnetic gap G1 extending in the circumferential direction is formed between the inner peripheral surface 19 of the stator 10 and the outer peripheral surface 29 of the rotor 20, as shown in Fig. 4. The magnetic gap G1 includes a first portion formed between the stator 10 and the first wall 31 of the frame 39 of the rotor 20, a second portion formed between the stator 10 and the second magnet 42, and a third portion formed between the stator 10 and the third magnet 43. As shown in Fig. 4, the radial width of the magnetic gap in the first portion is W1, and the radial width of the magnetic gap in the second portion and the third portion is W2.

[0017] 4, the second magnet 42 is adjacent to the side surface of the annular portion 36 on the magnetic gap G1 side, for example, the outer side surface S1 in the radial direction. The third magnet 43 is also adjacent to the side surface S1 of the annular portion 36.

[0018] As shown in Fig. 5, the frame 39 of the yoke 30 is formed by a first wall 31, a second wall 32, and a third wall 33. Fig. 5 is an enlarged perspective view showing an example of a rotor from which magnets have been removed in an embodiment. Fig. 5 shows the rotor 20 shown in Fig. 4 in a state before the first magnet 41, the second magnet 42, and the third magnet 43 are arranged.

[0019] 5 , in the embodiment, the second wall 32 and the third wall 33 are adjacent to the annular portion 36 in the radial direction and extend in the radial direction. The first wall 31 extends in the circumferential direction and is connected to the annular portion 36 in the radial direction via the second wall 32 and the third wall 33. The hole 38 is surrounded by a frame 39 that includes the first wall 31, the second wall 32, and the third wall 33.

[0020] As shown in Fig. 6, the first magnet 41 housed in the hole 38 is located between the first wall 31 and the annular portion 36 in the radial direction. Fig. 6 is an enlarged perspective view showing an example of a rotor in an embodiment. Fig. 6 is an enlarged view of the portion shown in frame F3 in Fig. 3.

[0021] 6, in the embodiment, the radial thickness T1 of the first wall 31 is greater than the circumferential thickness T2 of the second wall 32. In the embodiment, the circumferential thickness of the third wall 33 is substantially the same as the thickness T2 of the second wall 32. In other words, the thickness T1 of the first wall 31 is greater than the circumferential thickness of the third wall 33.

[0022] 5 and 6, an engagement portion 34 is formed in the frame 39 at the intersection of the first wall 31 and the second wall 32. Similarly, an engagement portion 35 is formed in the frame 39 at the intersection of the first wall 31 and the third wall 33. The engagement portion 35 is an example of another engagement portion. In the illustrated example, a corner of the second magnet 42 (near the intersection of the first surface 4a and the second surface 4b of the outer periphery) and a corner of the third magnet 43 (near the intersection of the first surface and the second surface of the outer periphery) are engaged with the engagement portion 34 and the engagement portion 35, respectively. The engagement portions 34 and 35 are formed as protrusions, and extend toward the corners (outer peripheries) of the second magnet 42 and the third magnet 43. The engagement portions 34 and 35 face the corners of the second magnet 42 and the third magnet 43.

[0023] As shown in FIGS. 4 and 6 , the second magnet 42 has a first surface 4a and a second surface 4b. The first surface 4a faces the frame 39 of the yoke 30 in the circumferential direction. Specifically, the first surface 4a faces the second wall 32 of the frame 39. For example, in the embodiment, the first surface 4a contacts the second wall 32 of the frame 39 in the circumferential direction. The second surface 4b faces the stator 10 in the radial direction. Similarly, as shown in FIG. 4 , the third magnet 43 has a first surface 4c facing the third wall 33 of the frame 39 and a second surface 4d facing the stator 10. More specifically, the second surface 4b of the second magnet 42 faces the stator 10 directly in the radial direction across a magnetic gap G1, and the second surface 4d of the third magnet 43 faces the stator 10 directly in the radial direction across a magnetic gap G1.

[0024] In the embodiment, the second magnet 42 and the third magnet 43 face the first magnet 41. In the circumferential direction, a second wall 32 is located between the first magnet 41 and the first surface 4a of the second magnet 42, and a third wall 33 is located between the first magnet 41 and the first surface 4c of the third magnet 43. For example, as shown in FIGS. 4 and 6, the second magnet 42 faces the first magnet 41 in the circumferential direction, with the second wall 32 sandwiched between them. Furthermore, as shown in FIG. 4, the third magnet 43 faces the first magnet 41 in the circumferential direction, with the third wall 33 sandwiched between them.

[0025] 4, the magnetic flux of the first magnet 41 is directed in the direction indicated by arrow M1, for example, radially outward (toward the stator 10). In the embodiment, the first wall 31 is positioned relative to the first magnet 41 in the direction M1 in which the magnetic flux of the first magnet 41 is directed. Specifically, the first wall 31 is disposed radially outward from the first magnet 41. This configuration prevents the first magnet 41 from flying out of the rotor 20 due to centrifugal force or magnetic repulsion when the rotor 20 rotates.

[0026] The magnetic flux of the second magnet 42 is directed in a direction M2 that is more inclined circumferentially than the direction M1 of the magnetic flux of the first magnet. Similarly, the direction M3 of the magnetic flux of the third magnet 43 is directed in a direction that is more inclined circumferentially than the direction M1 of the magnetic flux of the first magnet 41 and is different from the direction M2 of the magnetic flux of the second magnet.

[0027] Furthermore, the second magnet 42 engages with the engaging portion 34, and the third magnet 43 engages with the engaging portion 35. More specifically, as shown in FIGS. 4 and 6, the engaging portion 34 is disposed in accordance with the direction M2 of the magnetic flux of the second magnet 42. Furthermore, the engaging portion 35 is disposed in accordance with the direction M3 of the magnetic flux of the third magnet 43. In the embodiment, the engaging portion 34 is disposed radially outward from the second magnet, and the engaging portion 35 is disposed radially outward from the third magnet. With this configuration, the second magnet 42 and the third magnet 43 are prevented from flying out of the rotor 20 due to centrifugal force or magnetic repulsion when the rotor 20 rotates.

[0028] Furthermore, no magnetic material is arranged on the second surfaces 4b and 4d, which are the radially outer surfaces of the second magnet 42 and the third magnet 43. In other words, no yoke 30 is arranged radially outward of the second magnet 42 and the third magnet 43. The second magnet 42 and the third magnet 43 each directly face the stator 10 in the radial direction. This makes it easier for the magnetic flux of the second magnet 42 and the third magnet 43 to flow to the stator 10 and also suppresses circulation of magnetic flux between the second magnet 42 and the third magnet 43.

[0029] 4 and 6, by increasing the thickness T1 of the first wall 31 of the yoke 30, the radially outer surface of the first magnet is positioned radially inward relative to the second surface 4b of the second magnet 42 and the second surface 4d of the third magnet 43. This suppresses circulation of magnetic flux by the second magnet 42 and the third magnet 43, thereby increasing the magnetic flux flowing to the stator 10. Furthermore, by reducing the circumferential thickness of the second wall 32 and the third wall 33, the second wall 32 and the third wall 33 become magnetically saturated, thereby suppressing circulation of magnetic flux by the second magnet 42 and the third magnet 43, and further increasing the magnetic flux flowing to the stator 10.

[0030] As described above, the motor 1 in this embodiment includes the rotor 20 having the yoke 30, the first magnet 41, and the second magnet 42 adjacent to the first magnet 41, and the stator 10. The yoke 30 includes a hole 38 and a frame 39 surrounding the hole 38. The first magnet 41 is disposed within the hole 38 of the yoke 30, and the second magnet 42 includes a first surface 4a that faces the frame 39 of the yoke 30 in the circumferential direction and a second surface 4b that faces the stator 10 in the radial direction. With this configuration, the magnetic flux flowing from the magnets 41 to 43 to the stator 10 increases, thereby improving the output torque.

[0031] [Variations] Although the configuration of the embodiment has been described above, the embodiment is not limited to this. For example, while the configuration including two types of auxiliary magnets 42 and 43 has been described, the present invention is not limited to this, and a configuration including only one type of auxiliary magnet may be used, as shown in FIG. 7. Furthermore, the relationship between the thickness of the first wall 31 and the thicknesses of the second wall 32 and the third wall 33 in the frame 39 of the embodiment is not limited to that shown in FIG. 6. FIG. 7 is an enlarged top view showing an example of a rotor in a first modified example. Note that in the following modified examples, parts that are the same as those shown in the previously described drawings are assigned the same reference numerals, and duplicated explanations will be omitted.

[0032] As shown in Fig. 7, in the rotor 50 of the first modified example, the radial thickness T4 of the first wall 51 forming the frame 59 is smaller than the radial thickness T1 of the first wall 31 in the embodiment shown in Fig. 6. Note that, even in this case, the thickness T4 of the first wall 51 is preferably larger than the circumferential thickness T5 of the second wall 52 and the third wall 53.

[0033] 7, in the first modified example, a first magnet 61 having a different shape from the first magnet 41 in the embodiment is disposed in a hole 58 surrounded by a frame 59. In the first modified example, the first magnet 61 is surrounded by two second magnets 62 in the circumferential direction. In the first modified example, the two second magnets 62 have substantially the same shape. The directions M8 and M9 of the magnetic flux of the two second magnets 62 are opposite to each other.

[0034] 7, the configuration having a first magnet 61 and a second magnet 62 is easy to manufacture. On the other hand, the configuration having a first magnet 41, a second magnet 42, and a third magnet 43, as shown in Fig. 4, can reduce the effect of demagnetization. Furthermore, by increasing the size of the first magnet 61, the magnetic flux flowing from the first magnet 61 to the stator 10 can be increased.

[0035] Furthermore, although the motor 1 in the embodiment is an inner rotor type motor, the present invention is not limited to this and may be an outer rotor type motor, for example, as shown in FIG. 8. FIG. 8 is a perspective view showing an example of a motor in a second modified example. FIG. 9 is an enlarged perspective view showing an example of a motor in a second modified example. FIG. 9 is an enlarged view of the portion shown in frame F3 in FIG. 8.

[0036] As shown in Fig. 8, in the motor 2 of the second modification, the rotor 80 is disposed radially outward of the stator 70. Furthermore, as shown in Fig. 9, in the outer rotor type motor 2, the annular portion 86 of the rotor 80 is positioned radially outward of the magnet 40. For example, the first magnet 41 is disposed within a frame 89 formed by a first wall 81, a second wall 82, and a third wall 83.

[0037] In this case, the possibility of the magnet 40 flying out due to centrifugal force is small, but as in the embodiment, the amount of magnetic flux can be improved by making the radial thickness of the first wall 81 thicker than the circumferential thickness of the second wall 82 and the third wall 83, and by providing engagement portions 84 and 85 on the rotor 80.

[0038] The motor 2 in the second variant is also a flat motor, like the motor 1 in the embodiment, but is not limited to this, and in both the inner rotor type and the outer rotor type, the length of the motor in the axial direction may be greater than the length in the radial direction.

[0039] Furthermore, in the embodiment, the hole 38 and the first magnet 41 are both substantially rectangular in shape, but the embodiment is not limited to this. For example, the hole and the magnet may be formed to include a curved shape. Also, as shown in FIGS. 10 and 11, a rectangular magnet may be housed in a curved hole, or a magnet with a curved shape may be housed in a rectangular hole. FIG. 10 is an enlarged top view showing an example of a rotor in a third modified example. FIG. 11 is an enlarged top view showing an example of a rotor in a fourth modified example.

[0040] 10, in a rotor 90 according to the third modification, a hole 98 surrounded by a frame 99 formed by a first wall 91, a second wall 92, and a third wall 93 has an arc-shaped curved surface on the radially outer side. Also, a first magnet 41 is disposed in the hole 98 according to the third modification, as in the embodiment.

[0041] 11 , in the fourth modified example, a first magnet 69 is disposed in the same hole 58 of the rotor 50 as in the first modified example. The first magnet 69 differs from the first magnet 41 in the embodiment and the first magnet 61 in the first modified example in that both the radially outer surface and the radially inner surface are curved in an arc shape.

[0042] As described above, the rotor frame and the first magnet may have radially outer and inner surfaces that are different in shape or substantially the same in shape. Furthermore, the shapes of the radially outer and inner surfaces of the rotor frame may be different or substantially the same as shown in FIG. 10. Similarly, the shapes of the radially outer and inner surfaces of the first magnet may be different or substantially the same as shown in FIG. 11.

[0043] 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. [Explanation of symbols]

[0044] 1,2 motor, 10,70 stator, 11 stator core, 12 insulator, 13 coil, 14 end of conductor, 20,50,80,90 rotor, 30 yoke, 31,51,81,91 first wall, 32,52,82,92 second wall, 33,53,83,93 third wall, 34,35,84,85 rib (engagement portion), 36,86 annular portion, 38,58,98 hole, 39,59,89,99 frame, 41,61,69 first magnet, 42,62 second magnet, 43 third magnet, G1 magnetic gap

Claims

1. a rotor including a yoke, a plurality of first magnets, a second magnet facing the first magnets via the yoke, and a third magnet; a stator; Equipped with the yoke includes a plurality of holes and a plurality of frames surrounding the plurality of holes, the first magnets are disposed in the holes of the yoke; the second magnet and the third magnet are disposed between a first frame and a second frame that are adjacent to each other in the circumferential direction among the plurality of frames, the second magnet has a first surface facing the first frame of the yoke in the circumferential direction and a second surface facing the stator in the radial direction, the third magnet includes a first surface facing the second frame of the yoke in the circumferential direction and a second surface facing the stator in the radial direction, the second surface of the second magnet and the second surface of the third magnet form an outer circumferential surface or an inner circumferential surface of the rotor; Motor.

2. the frame includes a first wall, a second wall, and a third wall; the yoke includes an annular portion radially adjacent to the second wall and the third wall; The first magnet is located between the first wall and the annular portion in the radial direction. The motor according to claim 1 .

3. A motor as described in claim 2, wherein the thickness of the first wall in the radial direction is smaller than the thickness of the first magnet.

4. A rotor having a yoke, a first magnet, and a second magnet facing the first magnet; a stator; Equipped with the yoke includes a hole and a frame surrounding the hole; the first magnet is disposed within a hole in the yoke, the second magnet has a first surface facing a frame of the yoke in a circumferential direction and a second surface facing the stator in a radial direction, the frame includes a first wall extending in a circumferential direction, and second and third walls extending in a radial direction; the yoke includes an annular portion radially adjacent to the second wall and the third wall; the second surface of the second magnet forms an outer circumferential surface or an inner circumferential surface of the rotor, In the radial direction, the thickness of the first wall is smaller than the thickness of the first magnet. Motor.

5. The motor according to claim 2 , wherein a thickness of the first wall in a radial direction is greater than a thickness of the second wall or the third wall in a circumferential direction.

6. The motor according to claim 2 , wherein the second wall is located between the first magnet and the first surface of the second magnet in the circumferential direction.

7. a magnetic gap extending in a circumferential direction; a first portion of the magnetic gap is formed by the first wall and the stator in a radial direction; a second portion of the magnetic gap is formed in a radial direction by the second surface of the second magnet and the stator, the second magnet contacts a side surface of the annular portion on the magnetic gap side in the radial direction; 7. The motor according to claim 2.

8. an engaging portion is provided at a portion where the second wall and the first wall intersect, The second magnet is engaged with the engagement portion.

8. A motor according to any one of claims 2 to 7.

9. The magnetic flux of the first magnet is directed in a radial direction, 9. The motor according to claim 2, wherein the direction of the magnetic flux of the second magnet is inclined in the circumferential direction relative to the direction of the magnetic flux of the first magnet.

10. the rotor includes a third magnet facing the first magnet, The third magnet has a first surface facing a frame of the yoke in a circumferential direction and a second surface facing the stator in a radial direction.

10. A motor according to any one of claims 2 to 9.

11. The motor according to claim 10, wherein the first magnet is located between the second magnet and the third magnet in the circumferential direction, and the third wall is located between the first magnet and the first surface of the third magnet.

12. a magnetic gap extending in a circumferential direction; a third portion of the magnetic gap is formed in a radial direction by the second surface of the third magnet and the stator, the third magnet is in contact with a side surface of the annular portion on the magnetic gap side; 12. The motor according to claim 10 or 11.

13. another engaging portion is provided at a portion where the third wall and the first wall intersect, the third magnet is engaged with the other engaging portion; 13. A motor according to any one of claims 10 to 12.

14. The magnetic flux of the first magnet is directed in a radial direction, 14. The motor according to claim 10, wherein the direction of the magnetic flux of the third magnet is inclined circumferentially more than the direction of the magnetic flux of the first magnet and is different from the direction of the magnetic flux of the second magnet.

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