Rotor

Abstract

The invention provides a rotor. A magnet provided in a rotor of an electric motor has: a first main side surface facing radially outward; a second main side surface positioned on the opposite side from the first main side surface; and a first sub-side surface extending between the first main side surface and the second main side surface. The magnet hole has: a first inner surface facing the first main side surface; a second inner surface that faces the second main side surface; and a first positioning portion protruding from the second inner surface and facing the first sub-side surface. The number of overlapping sheets between the first sub-side surface and the first positioning portion is greater than the number of overlapping sheets between the first main side surface and the first inner surface.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a rotor, and particularly to a rotor of an electric motor. Background Art

[0002] A rotor is described in Japanese Unexamined Patent Application Publication No. 2017-077086. The rotor includes: a rotor core having magnet holes extending in an axial direction parallel to the rotation axis of the rotor; magnets inserted into the magnet holes and having a plurality of side surfaces extending in the axial direction; and a sheet. The sheet covers a first main side surface having a first magnetic pole and facing the outer side in the radial direction, and a second main side surface having a second magnetic pole and located on the opposite side of the first main side surface.

[0003] There is a known technology of positioning or fixing a magnet by providing a protrusion on the inner surface of a magnet hole in a rotor as described above. Since such a protrusion comes into partial contact with the magnet, excessive stress may be generated in the magnet. To avoid this, it is considered to wind the sheet around the side surface of the magnet in multiple layers. However, if the side surface of the magnet is covered with the sheet in multiple layers, the multiple layers of the sheet act as a barrier to magnetic flux, and thus there is a problem that the magnetic characteristics of the rotor are reduced. Summary of the Invention

[0004] In view of the above circumstances, this specification provides a technology that can suppress the influence on the magnetic characteristics of the rotor and protect the magnet from the influence of the protrusion provided in the magnet hole.

[0005] The technology disclosed in this specification is embodied as a rotor of an electric motor. The rotor according to one aspect of the present disclosure includes: a rotor core having a magnet hole extending in an axial direction parallel to the rotation axis of the rotor; a magnet inserted into the magnet hole and having a plurality of side surfaces extending in the axial direction; and a sheet wound around the plurality of side surfaces of the magnet. The plurality of side surfaces of the magnet include: a first main side surface having a first magnetic pole and facing outward in the radial direction; a second main side surface having a second magnetic pole and located on the side opposite to the first main side surface; a first sub-side surface extending between the first main side surface and the second main side surface; and a second sub-side surface extending between the first main side surface and the second main side surface and located on the side opposite to the first sub-side surface. The magnet hole includes: a first inner surface facing the first main side surface of the magnet; a second inner surface facing the second main side surface of the magnet; and a first positioning portion protruding from the second inner surface and facing the first sub-side surface of the magnet. The number of overlapping sheets of the sheet located between the first sub-side surface of the magnet and the first positioning portion of the magnet hole is larger than the number of overlapping sheets of the sheet located between the first main side surface of the magnet and the first inner surface of the magnet hole.

[0006] In the above rotor, in order to position the magnet with respect to the magnet hole, a first positioning portion is provided on the second inner surface of the magnet hole. The first positioning portion protrudes from the second inner surface of the magnet hole and faces the first sub-side surface of the magnet. Therefore, it is assumed that the first positioning portion of the magnet hole is in partial contact with the first sub-side surface of the magnet. However, a sheet is wound around a plurality of side surfaces of the magnet including the first sub-side surface, and multiple layers of the sheet are interposed between the first sub-side surface of the magnet and the first positioning portion of the magnet hole. Thereby, the contact between the first sub-side surface of the magnet and the first positioning portion can be effectively protected. On the other hand, for the first main side surface having a magnetic pole and facing the stator, it is covered only by a relatively small number of layers (including one layer) of the sheet. Thereby, the influence on the magnetic characteristics of the rotor can be suppressed, and the magnet can be protected from the influence of the first positioning portion provided in the magnet hole.

[0007] In the second aspect, based on the first aspect, the number of overlapping sheets of the sheet located between the first sub-side surface of the magnet and the first positioning portion of the magnet hole may also be two. In this case, the number of overlapping sheets of the sheet located between the first main side surface of the magnet and the first inner surface of the magnet hole may also be one. However, the above-mentioned number of overlapping sheets may also be more, and can be appropriately designed according to the material, thickness, etc. of the sheet.

[0008] In the third mode, on the basis of the first or the second mode described above, the magnet hole may further have a second positioning portion that protrudes from the second inner surface and faces the second secondary side surface of the magnet. In this case, the number of overlapping sheets of the sheet material located between the second secondary side surface of the magnet and the second positioning portion of the magnet hole may also be greater than the number of overlapping sheets of the sheet material located between the first main side surface of the magnet and the first inner surface of the magnet hole. In this way, there may be multiple positioning portions in the magnet hole. In this case, each positioning portion can be covered with multiple layers of sheet material.

[0009] In the fourth mode, on the basis of the third mode described above, the number of overlapping sheets of the sheet material located between the second secondary side surface of the magnet and the second positioning portion of the magnet hole may also be two sheets. In this case, the number of overlapping sheets of the sheet material located between the first main side surface of the magnet and the first inner surface of the magnet hole may also be one sheet. However, the above-mentioned number of overlapping sheets may also be a larger number, and can be appropriately designed according to the material, thickness, etc. of the sheet material.

[0010] In the fifth mode, on the basis of any one of the first mode to the fourth mode described above, the number of overlapping sheets of the sheet material located between the second main side surface of the magnet and the second inner surface of the magnet hole may also be greater than the number of overlapping sheets of the sheet material located between the first main side surface of the magnet and the first inner surface of the magnet hole. With such a structure, compared with the second main side surface facing the inner side in the radial direction, the first main side surface facing the outer side in the radial direction is covered with fewer sheets, so the influence on the magnetic characteristics of the rotor can be suppressed.

[0011] In the sixth mode, on the basis of any one of the first mode to the fifth mode described above, the sheet material may also be composed of a single sheet-like component. In this case, one end of the initial roll of the single sheet-like component is located on one of the first secondary side surface and the second secondary side surface of the magnet. In addition, one end of the final roll of the single sheet-like component may also be located on the other of the first secondary side surface and the second secondary side surface of the magnet. With such a structure, since there are no ends of the sheet material on the first main side surface and the second main side surface having magnetic poles, the influence on the magnetic characteristics of the rotor can be suppressed.

[0012] In the seventh mode, on the basis of any one of the first mode to the sixth mode described above, the magnet hole may further have at least one riveting portion that protrudes from the second inner surface and abuts against the second main side surface of the magnet via the sheet material. In this case, the number of overlapping sheets of the sheet material located between the second main side surface of the magnet and the riveting portion of the magnet hole may also be greater than the number of overlapping sheets of the sheet material located between the first main side surface of the magnet and the first inner surface of the magnet hole.

[0013] In the above-described manner, in order to fix the magnet relative to the magnet hole, a riveting portion is provided on the second inner surface of the magnet hole. The riveting portion protrudes from the second inner surface of the magnet hole. However, since a plurality of sheets are interposed between the riveting portion of the magnet hole and the second main side surface of the magnet, the contact between the second main side surface of the magnet and the riveting portion of the magnet hole can be effectively protected. On the other hand, the first main side surface having magnetic poles and facing the stator is covered with a sheet having a relatively small number of layers (including one layer). Thereby, the influence on the magnetic characteristics of the rotor can be suppressed, and the magnet can be protected from the influence of the riveting portion provided in the magnet hole.

[0014] In the eighth embodiment, based on the seventh embodiment described above, the number of overlapping sheets between the second main side surface of the magnet and the riveting portion of the magnet hole may be equal to the number of overlapping sheets between the first sub-side surface of the magnet and the first positioning portion of the magnet hole. However, as another embodiment, the number of overlapping sheets between the second main side surface of the magnet and the riveting portion of the magnet hole may be less than or more than the number of overlapping sheets between the first sub-side surface of the magnet and the first positioning portion of the magnet hole.

[0015] In the ninth embodiment, based on any one of the first to eighth embodiments described above, at least a part of the sheet may be made of a foaming material. With such a structure, since the space between the magnet and the magnet hole is filled with the foaming material without any gaps, the position of the magnet is stable. In addition, because the foaming material has high flexibility, the side surfaces of the magnet can be effectively protected against protrusions such as the first positioning portion, the second positioning portion, and / or the riveting portion.

[0016] In the tenth embodiment, based on any one of the first to ninth embodiments described above, at least a part of the sheet may be made of an insulating material. With such a structure, electrical insulation can be achieved between the magnet and the magnet hole, and losses caused by eddy currents in the rotor can be suppressed.

[0017] In the eleventh embodiment, based on any one of the first to tenth embodiments described above, at least a part of the sheet may be made of an adhesive material. With such a structure, the magnet can be fixed relative to the magnet hole by the adhesive material of the sheet.

[0018] In the twelfth embodiment, based on any one of the first to eleventh embodiments described above, at least a part of the magnet hole may be filled with a filling material outside the sheet. With such a structure, the magnet can be fixed relative to the magnet hole by the filling material.

[0019] The technology disclosed in this specification is embodied in the rotors of other electric motors. The rotor according to another aspect of the present disclosure includes: a rotor core having magnet holes extending in the axial direction parallel to the rotation axis of the rotor; magnets inserted into the magnet holes and having a plurality of side surfaces extending in the axial direction; and sheets wound around the plurality of side surfaces of the magnets. The plurality of side surfaces of the magnets include: a first main side surface having a first magnetic pole and facing the outer side in the radial direction; a second main side surface having a second magnetic pole and located on the side opposite to the first main side surface; a first sub-side surface extending between the first main side surface and the second main side surface; and a second sub-side surface extending between the first main side surface and the second main side surface and located on the side opposite to the first sub-side surface. The magnet holes include: a first inner surface facing the first main side surface of the magnet; a second inner surface facing the second main side surface of the magnet; and a riveting portion protruding from the second inner surface and abutting against the second main side surface of the magnet via the sheets. The number of overlapping sheets of the sheets located between the second main side surface of the magnet and the riveting portion of the magnet hole is larger than the number of overlapping sheets of the sheets located between the first main side surface of the magnet and the first inner surface of the magnet hole.

[0020] In the above rotor, in order to fix the magnet with respect to the magnet hole, a riveting portion is provided on the second inner surface of the magnet hole. The riveting portion protrudes from the second inner surface of the magnet hole, but since a plurality of sheets are interposed between the riveting portion of the magnet hole and the second main side surface of the magnet, the abutment between the second main side surface of the magnet and the riveting portion of the magnet hole can be effectively protected. On the other hand, the first main side surface having a magnetic pole and facing the stator is covered with sheets having a relatively small number of layers (including one layer). Thereby, the influence on the magnetic characteristics of the rotor can be suppressed, and the magnet can be protected from the influence of the riveting portion provided in the magnet hole.

[0021] In the 14th aspect, on the basis of the above another aspect, at least a part of the magnet hole may be filled with a filling material outside the sheets. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Hereinafter, the features, advantages, and technical and industrial significance of the embodiments of the present invention will be described with reference to the drawings, and the same reference numerals denote the same elements, wherein,

[0023] Figure 1 is a schematic view of an electric motor 100 employing the rotor 10 of Example 1 as viewed from a direction perpendicular to the rotation axis R. In addition, for the rotor 10, a cross section of a portion on the left side of the paper surface with respect to the rotation axis R is shown.

[0024] Figure 2 is Figure 1 A cross-sectional view taken along line II-II, showing one end face of the rotor core 14 in the axial direction.

[0025] Figure 3 is Figure 2 An enlarged view of part III in

[0026] Figure 4 A view showing the structure of the rotor 110 of Example 2, which is an enlarged view corresponding to Figure 3 corresponding one.

[0027] Figure 5 A view showing the structure of the rotor 210 of Example 3, which is an enlarged view corresponding to Figure 3 corresponding one.

[0028] Figure 6 A view showing the structure of the rotor 310 of Example 4, which is an enlarged view corresponding to Figure 3 corresponding one.

[0029] Figure 7 A view showing the structure of the rotor 410 of Example 5, which is an enlarged view corresponding to Figure 3 corresponding one.

[0030] Figure 8 A view showing the structure of the rotor 510 of Example 6, which is an enlarged view corresponding to Figure 3 corresponding one. Detailed implementation mode

[0031] Example 1

[0032] The rotor 10 of Example 1 will be described with reference to the accompanying drawings. The rotor 10 of this example is used in the electric motor 100. The electric motor 100 includes a rotor 10, a stator 102, and a housing 104. The housing 104 is a frame member. The housing 104 houses the rotor 10 and the stator 102. As an example, the housing 104 is mainly made of metal. The rotor 10 is supported so as to be rotatable about the rotation axis R with respect to the housing 104. Although not particularly limited, the housing 104 may further house a power transmission mechanism such as a reduction mechanism and a differential mechanism (not shown).

[0033] The stator 102 generally has a cylindrical shape centered on the rotation axis R. The stator 102 is disposed on the outer side in the radial direction of the rotor 10. The stator 102 is fixed to the inner wall of the housing 104. The stator 102 includes a stator core 102a and a stator coil 102b. The stator core 102a is made of a soft magnetic material such as electromagnetic steel, for example. As an example, the stator core 102a in the present embodiment is formed by laminating a plurality of electromagnetic steel sheets. The stator coil 102b is configured to be wound around the stator core 102a and magnetize the stator core 102a. As an example, the electric motor 100 in the present embodiment is a three-phase motor, and the stator coil 102b includes one or more U-phase coils, one or more V-phase coils, and one or more W-phase coils. However, the specific structure of the stator 102 is not particularly limited.

[0034] As Figure 1 , 2 shown, the rotor 10 includes a shaft 12 and a rotor core 14. The shaft 12 is arranged such that its central axis coincides with the rotation axis R. The shaft 12 is made of a metal such as stainless steel, for example. The rotor core 14 is located on the outer side in the radial direction of the shaft 12 and has a cylindrical shape extending parallel to the rotation axis R. The rotor core 14 is made of a soft magnetic material such as electromagnetic steel, for example. As an example, the rotor core 14 in the present embodiment is formed by laminating a plurality of electromagnetic steel sheets. A through hole 14a is provided at the center of the rotor core 14, and the shaft 12 is inserted through the through hole 14a. The rotor core 14 is fixed to the shaft 12 to prohibit relative rotation with respect to the shaft 12.

[0035] As Figure 1 , 2 shown, the rotor 10 further includes a plurality of magnet holes 16a, 16b and a plurality of magnets 18. The plurality of magnet holes 16a, 16b are located in the outer peripheral portion of the rotor core 14 and are regularly arranged in the circumferential direction. Each of the magnet holes 16a, 16b extends in the axial direction parallel to the rotation axis R of the rotor 10. The cross-sectional shape of each of the magnet holes 16a, 16b is a cut groove shape extending in the circumferential direction, but the long side axis of the cut groove shape has an angle with respect to the circumferential direction. The plurality of magnet holes 16a, 16b include multiple pairs of first magnet holes 16a and multiple pairs of second magnet holes 16b. Each pair of first magnet holes 16a is symmetrically arranged in the circumferential direction of the rotor core 14. One magnet 18 is inserted into each of the first magnet holes 16a. Similarly, each pair of second magnet holes 16b is symmetrically arranged in the circumferential direction of the rotor core 14. Each pair of second magnet holes 16b is located on the inner side in the radial direction with respect to the corresponding pair of first magnet holes 16a. Two magnets 18 are inserted into each of the second magnet holes 16b. Each magnet 18 has a substantially rectangular parallelepiped shape extending in the axial direction parallel to the rotation axis R of the rotor 10. Although not particularly limited, each magnet 18 is a permanent magnet.

[0036] Next, referring to Figure 3The structure of one first magnet hole 16a and the magnet 18 inserted therein will be described. In addition, the structures described below are also identically adopted in other first magnet holes 16a and the magnets 18 inserted therein, second magnet holes 16b, and the two magnets 18 inserted therein.

[0037] As Figure 3 shown, the magnet 18 has a plurality of side surfaces 20, 22, 24, 26 extending in the axial direction. For the plurality of side surfaces 20, 22, 24, 26, the first main side surface 20, the second main side surface 22, the first sub-side surface 24, and the second sub-side surface 26 are included. The first main side surface 20 has a first magnetic pole and faces the outer side in the radial direction. In addition, the so-called first main side surface 20 facing the outer side in the radial direction means that the normal vector of the first main side surface 20 includes at least a component facing the outer side in the radial direction. That is, each of the plurality of magnets 18 may not necessarily be perpendicular to the radial direction and may be inclined with respect to the radial direction respectively. The first magnetic pole is either an N pole or an S pole. In the electric motor 100, the first main side surface 20 of the rotor 10 faces the stator 102. The second main side surface 22 has a second magnetic pole and is located on the opposite side of the first main side surface 20. The second magnetic pole is the opposite pole of the first magnetic pole and is either the other of the N pole or the S pole. The first sub-side surface 24 extends between the first main side surface 20 and the second main side surface 22. The second sub-side surface 26 extends between the first main side surface 20 and the second main side surface 22 and is located on the opposite side of the first sub-side surface 24. When the rotor 10 is viewed from the direction parallel to the rotation axis R, the first main side surface 20, the first sub-side surface 24, the second main side surface 22, and the second sub-side surface 26 are arranged in series in this order. The respective areas of the first main side surface 20 and the second main side surface 22 are larger than the respective areas of the first sub-side surface 24 and the second sub-side surface 26.

[0038] As Figure 3 shown, the first magnet hole 16a has a first inner surface 28 and a second inner surface 30. The first inner surface 28 faces the first main side surface 20 of the magnet 18. The second inner surface 30 faces the second main side surface 22 of the magnet 18. A first positioning portion 32 and a second positioning portion 34 are provided on the second inner surface 30. These positioning portions 32, 34 are parts for positioning the magnet 18 with respect to the first magnet hole 16a. The first positioning portion 32 protrudes from the second inner surface 30 and faces the first sub-side surface 24 of the magnet 18. The second positioning portion 34 protrudes from the second inner surface 30 and faces the second sub-side surface 26 of the magnet 18. Since the second inner surface 30 of the first magnet hole 16a has an angle with respect to the circumferential direction, the first positioning portion 32 is located at a position closer to the inner side in the radial direction than the second positioning portion 34.

[0039] In the above-described rotor 10, in order to position the magnet 18 relative to the first magnet hole 16a, positioning portions 32 and 34 are provided on the second inner surface 30 of the first magnet hole 16a. The positioning portions 32 and 34 project from the second inner surface 30 of the first magnet hole 16a and face the sub-side surfaces 24 and 26 of the magnet 18. Therefore, it is assumed that the positioning portions 32 and 34 of the first magnet hole 16a are in partial contact with the sub-side surfaces 24 and 26 of the magnet 18.

[0040] Regarding the above point, as Figure 3 shown, the rotor 10 further includes a sheet 36. The sheet 36 in this embodiment is composed of a single sheet-like member. The sheet 36 is wound around a plurality of side surfaces 20, 22, 24, and 26 of the magnet 18. As an example, the starting end 36a of the sheet 36 is located on the first sub-side surface 24 of the magnet 18, and the ending end 36b of the sheet 36 is located on the second sub-side surface 26 of the magnet 18. For example, in the manufacturing process of the rotor 10, starting from the state where one end 36a of the sheet 36 is located on the first sub-side surface 24 of the magnet 18, the sheet 36 is wound around the magnet 18. At this time, the second main side surface 22, the second sub-side surface 26, and the first main side surface 20 are sequentially covered by the sheet 36. When the sheet 36 again reaches the state of being located on the second sub-side surface 26 of the magnet 18, the sheet 36 is cut. As a result, the starting end 36a of the sheet 36 is located on the first sub-side surface 24 of the magnet 18, and the ending end 36b of the sheet 36 is located on the second sub-side surface 26 of the magnet 18. In other words, the starting end 36a of the sheet 36 is the innermost end of the sheet 36 wound around the magnet 18, and the ending end 36b of the sheet 36 is the outermost end of the sheet 36 wound around the magnet 18.

[0041] In this embodiment, the number of overlapping sheets of the sheet 36 between the first sub-side surface 24 of the magnet 18 and the first positioning portion 32 of the first magnet hole 16a is two, and the number of overlapping sheets of the sheet 36 between the first main side surface 20 of the magnet 18 and the first inner surface 28 of the first magnet hole 16a is one. In addition, the number of overlapping sheets of the sheet 36 between the second sub-side surface 26 of the magnet 18 and the second positioning portion 34 of the first magnet hole 16a is two, and the number of overlapping sheets of the sheet 36 between the second main side surface 22 of the magnet 18 and the second inner surface 30 of the first magnet hole 16a is two.

[0042] If based on such a structure, the abutment between the secondary side surfaces 24 and 26 of the magnet 18 and the positioning portions 32 and 34 can be effectively protected. On the other hand, for the first main side surface 20 having magnetic poles and facing the stator 102, it is covered only by the sheet 36 with a relatively small number of layers (one layer in this embodiment). Thus, the influence on the magnetic characteristics of the rotor 10 can be suppressed, and the magnet 18 can be protected from the influence of the positioning portions 32 and 34 provided in the first magnet hole 16a.

[0043] Although not particularly limited, in the above-mentioned rotor 10, as Figure 3 shown, the number of overlapping sheets 36 (two layers in this embodiment) between the second main side surface 22 of the magnet 18 and the second inner surface 30 of the first magnet hole 16a is more than the number of overlapping sheets 36 (one layer in this embodiment) between the first main side surface 20 of the magnet 18 and the first inner surface 28 of the magnet hole 16a. If based on such a structure, since the first main side surface 20 facing the outer side in the radial direction is covered by fewer sheets 36 than the second main side surface 22 facing the inner side in the radial direction, the influence on the magnetic characteristics of the rotor 10 can be suppressed.

[0044] In this embodiment, the number of overlapping sheets 36 between the secondary side surfaces 24 and 26 of the magnet 18 and the positioning portions 32 and 34 of the first magnet hole 16a is two, and the number of overlapping sheets 36 between the first main side surface 20 of the magnet 18 and the first inner surface 28 of the first magnet hole 16a is one. However, as another embodiment, the above-mentioned number of overlapping sheets can also be more. In this case, it is sufficient that the number of overlapping sheets 36 between the secondary side surfaces 24 and 26 of the magnet 18 and the positioning portions 32 and 34 of the first magnet hole 16a is more than the number of overlapping sheets 36 between the first main side surface 20 of the magnet 18 and the first inner surface 28 of the first magnet hole 16a. In addition, the number of overlapping sheets 36 between the first secondary side surface 24 of the magnet 18 and the first positioning portion 32 of the first magnet hole 16a can be more than or less than the number of overlapping sheets 36 between the second secondary side surface 26 of the magnet 18 and the second positioning portion 34 of the first magnet hole 16a.

[0045] In this embodiment, two positioning portions 32 and 34 are provided in the first magnet hole 16a. However, the number of positioning portions 32 and 34 provided in the first magnet hole 16a is not particularly limited. As another embodiment, one positioning portion can also be provided in the first magnet hole 16a. In this case, this positioning portion can be covered by multiple sheets 36. Or, as another embodiment, three or more positioning portions can also be provided in the first magnet hole 16a. In this case, each positioning portion can be covered by multiple sheets 36.

[0046] In this embodiment, one end 36a of the starting coil of the sheet 36 is located on the first secondary side surface 24 of the magnet 18, and one end 36b of the ending coil of the sheet 36 is located on the second secondary side surface 26 of the magnet 18. With such a structure, since one ends 36a and 36b of the sheet 36 are not present on the first main side surface 20 and the second main side surface 22 having magnetic poles, the influence on the magnetic characteristics of the rotor 10 can be suppressed. In addition, as another embodiment, it may be configured such that one end 36a of the starting coil of the sheet 36 is located on the second secondary side surface 26 of the magnet 18, and one end 36b of the ending coil of the sheet 36 is located on the first secondary side surface 24 of the magnet 18. Further, the sheet 36 does not necessarily have to be constituted by a single sheet-like member, and may be constituted by combining a plurality of sheet-like members. For example, the sheet 36 may be constituted by a first sheet covering a plurality of side surfaces 20, 22, 24, and 26 of the magnet 18, and a second sheet further covering the second main side surface 22 covered by the first sheet.

[0047] Although not particularly limited, at least a part of the sheet 36 in this embodiment is constituted by a foaming material. With such a structure, since the space between the magnet 18 and the first magnet hole 16a is filled with the foaming material without any gaps, the position of the magnet 18 is stable. In addition, since the foaming material has high flexibility, it can effectively protect the side surfaces 20, 22, 24, and 26 of the magnet 18 against protrusions such as the positioning portions 32 and 34.

[0048] In addition to or instead of the above, at least a part of the sheet 36 in this embodiment is constituted by an insulating material. With such a structure, electrical insulation can be achieved between the magnet 18 and the first magnet hole 16a, and losses caused by eddy currents in the rotor 10 can be suppressed.

[0049] In addition to or instead of the above, at least a part of the sheet 36 in this embodiment is constituted by an adhesive material. With such a structure, the magnet 18 can be fixed relative to the first magnet hole 16a by the adhesive material of the sheet 36.

[0050] In this embodiment, each pair of second magnet holes 16b is located radially inside the corresponding pair of first magnet holes 16a, and magnets 18 are inserted into the magnet holes 16a and 16b. Therefore, the plurality of magnets 18 includes magnets 18 inserted into the first magnet holes 16a and arranged radially outside, and magnets 18 inserted into the second magnet holes 16b and arranged radially inside. That is, in this embodiment, the plurality of magnets 18 are arranged in two layers in the radial direction. However, the plurality of magnets 18 do not necessarily have to be arranged in two layers in the radial direction. In other embodiments, the plurality of magnets 18 can be arranged in one layer in the radial direction or can be arranged in three or more layers. In addition, in each of the above layers, the plurality of magnets 18 can be repeatedly arranged in a V shape.

[0051] In this embodiment, each magnet 18 has a substantially rectangular parallelepiped shape extending along the axial direction parallel to the rotation axis R of the rotor 10. However, each magnet 18 does not necessarily have to have a substantially rectangular parallelepiped shape. For example, as another embodiment, each magnet 18 can have a plate shape with a first main side surface 20 and a second main side surface 22 curved. In addition, the magnets with such curvature can be arranged in two or more layers in the radial direction.

[0052] Embodiment 2

[0053] Refer to Figure 4 to describe the rotor 110 of Embodiment 2. As Figure 4 shown, in the rotor 110 of Embodiment 2, compared with the rotor 10 of Embodiment 1, a riveting portion 38 is provided in the first magnet hole 16a. For the remaining structures, they are the same as those of the rotor 10 of Embodiment 1, so the repeated description is omitted here. In addition, the structure related to the first magnet hole 16a described in this embodiment is also adopted in the other first magnet holes 16a and second magnet holes 16b.

[0054] As Figure 4 shown, the riveting portion 38 protrudes from the second inner surface 30 and abuts against the second main side surface 22 of the magnet 18 via the sheet 36. In this case, the number of overlapping sheets 36 (two layers in this embodiment) between the second main side surface 22 of the magnet 18 and the riveting portion 38 of the first magnet hole 16a is more than the number of overlapping sheets 36 (one layer in this embodiment) between the first main side surface 20 of the magnet 18 and the first inner surface 28 of the first magnet hole 16a. In addition, the number and arrangement of the riveting portions 38 are not particularly limited, and it is only necessary that the riveting portion 38 protrudes from the second inner surface 30 and abuts against the second main side surface 22 of the magnet 18 via the sheet 36. Although not particularly limited, in the rotor 110 of this embodiment, the riveting portion 38 is formed by engraving, and there is a scratch 40 near the riveting portion 38 on the end surface in the axial direction of the rotor 110.

[0055] In the rotor 110 of Embodiment 2, in order to fix the magnet 18 relative to the first magnet hole 16a, a riveting portion 38 is provided on the second inner surface 30 of the first magnet hole 16a. The riveting portion 38 protrudes from the second inner surface 30 of the first magnet hole 16a. However, since a multilayer sheet 36 is interposed between the riveting portion 38 of the first magnet hole 16a and the second main side surface 22 of the magnet 18, the contact between the second main side surface 22 of the magnet 18 and the riveting portion 38 of the first magnet hole 16a can be effectively protected. On the other hand, the first main side surface 20 having magnetic poles and facing the stator 102 is covered with a sheet 36 having a relatively small number of layers (including one layer). Thereby, the influence on the magnetic characteristics of the rotor 110 can be suppressed, and the magnet 18 can be protected from the influence of the riveting portion 38 provided in the first magnet hole 16a.

[0056] As described above, regarding the structure related to the first magnet hole 16a described in Embodiment 2, the same structure is also adopted in other first magnet holes 16a and a plurality of second magnet holes 16b. That is, in these magnet holes 16a, 16b, a riveting portion 38 is also provided on the second inner surface 30. Moreover, the number of overlapping sheets 36 between the second main side surface 22 of the magnet 18 and the riveting portions 38 of the magnet holes 16a, 16b is larger than the number of overlapping sheets 36 between the first main side surface 20 of the magnet 18 and the first inner surface 28 of the magnet holes 16a, 16b.

[0057] Although not particularly limited, in the rotor 110 of Embodiment 2, the number of overlapping sheets 36 between the second main side surface 22 of the magnet 18 and the riveting portion 38 of the first magnet hole 16a is equal to the number of overlapping sheets 36 between the first sub - side surface 24 of the magnet 18 and the positioning portions 32, 34 of the first magnet hole 16a. However, as another embodiment, the number of overlapping sheets 36 between the second main side surface 22 of the magnet 18 and the riveting portion 38 of the first magnet hole 16a may be less than or more than the number of overlapping sheets 36 between the first sub - side surface 24 of the magnet 18 and the positioning portions 32, 34 of the first magnet hole 16a.

[0058] Embodiment 3

[0059] Refer to Figure 5 The rotor 210 of Embodiment 3 will be described. As Figure 5 shown, compared with the rotor 10 of Embodiment 1, a filling material 42 is filled in the first magnet hole 16a of the rotor 210 of Embodiment 3. For the remaining structures, they are the same as those of the rotor 10 of Embodiment 1, so the repeated description is omitted here. In addition, although not shown in the figure, the same filling material 42 is also filled in other first magnet holes 16a and second magnet holes 16b.

[0060] As Figure 5As shown, the filling material 42 fills the gap between the first magnet hole 16a and the sheet 36 on the outside of the sheet 36. With such a structure, the magnet 18 is fixed relative to the first magnet hole 16a. However, the filling material 42 does not necessarily have to completely fill the gap between the first magnet hole 16a and the sheet 36. The filling material 42 may also be filled in at least a part of the gap. The material constituting the filling material 42 is not particularly limited. As an example, the material constituting the filling material 42 may be an electrically insulating material, or may be a non-magnetic material magnetically. As an example, the filling material 42 in the present embodiment is a resin material, particularly a thermosetting resin material.

[0061] As an example, as Figure 5 shown, the range filled with the filling material 42 in the first magnet hole 16a is mainly provided on both sides of the magnet 18. That is, the gap between the first magnet hole 16a and the magnet 18 is divided into a first region located on the side of the first sub-side surface 24 of the first magnet hole 16a and a second region located on the side of the second sub-side surface 26 of the first magnet hole 16a. Here, in the first region, one end 36a of the starting roll of the sheet 36 is positioned, and this one end 36a of the starting roll does not come into direct contact with the filling material 42. On the other hand, in the second region, one end 36b of the ending roll of the sheet 36 is positioned, and this one end 36b of the ending roll comes into direct contact with the filling material 42. Thus, in the manufacture of the rotor 210, when filling the filling material 42 into the gap between the first magnet hole 16a and the magnet 18, the filling material 42 can be filled starting from the first region where the one end 36a of the starting roll is located. Thus, it is difficult for the filling material 42 to intrude into the inside of the sheet 36, and it is possible to avoid bending and breaking of the sheet 36.

[0062] Example 4

[0063] Refer to Figure 6 to describe the rotor 310 of Example 4. As Figure 6 shown, comparing the rotor 310 of Example 4 with the rotor 110 of Example 2, the filling material 42 is filled in the first magnet hole 16a. For the remaining structure, it is the same as the rotor 110 of Example 2, so the repeated description is omitted here. In addition, although not shown in the figure, the same filling material 42 is also filled in the other first magnet hole 16a and the second magnet hole 16b. Since the structure, function, and effect of the filling material 42 in the present embodiment are the same as those of the filling material 42 in Example 3, the repeated description is omitted here.

[0064] Example 5

[0065] Refer to Figure 7 to describe the rotor 410 of Example 5. As Figure 7As shown, when comparing the rotor 410 of Example 5 with the rotor 10 of Example 1, a riveting portion 38 is provided in the first magnet hole 16a instead of the positioning portions 32 and 34. In other words, the rotor 410 of Example 5 is a rotor obtained by removing the positioning portions 32 and 34 from the rotor 110 of Example 2. In addition, in the other first magnet holes 16a and second magnet holes 16b, the positioning portions 32 and 34 are not provided in the same way, and in this regard, it is different from the rotor 110 of Example 2. Regarding the remaining structure, it is the same as the rotor 110 of Example 2, so the repeated description is omitted here.

[0066] Example 6

[0067] Refer to Figure 8 to describe the rotor 510 of Example 6. As Figure 8 shown, when comparing the rotor 510 of Example 6 with the rotor 410 of Example 5, a filling material 42 is filled in the first magnet hole 16a. In addition, although not shown in the figure, the same filling material 42 is also filled in the other first magnet holes 16a and second magnet holes 16b. Since the structure, function, and effect of the filling material 42 in this embodiment are the same as those of the filling material 42 in Examples 3 and 4, the repeated description is omitted here.

[0068] As mentioned above, several specific examples have been described in detail, but these are only illustrative and do not limit the scope of the claims. For the technologies described in the claims, they include technologies obtained by various deformations and changes to the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in combination.

Claims

1. A rotor, which is a rotor of an electric motor, characterized in that, Comprising: A rotor core having magnet holes extending axially parallel to the rotation axis of the rotor; Magnets inserted into the magnet holes and having a plurality of side surfaces extending in the axial direction; And A sheet wound around the plurality of side surfaces of the magnet, The plurality of side surfaces of the magnet having: A first main side surface having a first magnetic pole and facing outward in the radial direction; A second main side surface having a second magnetic pole and located on the side opposite to the first main side surface; A first sub-side surface extending between the first main side surface and the second main side surface; And A second sub-side surface extending between the first main side surface and the second main side surface and located on the side opposite to the first sub-side surface, The magnet hole having: A first inner surface opposed to the first main side surface of the magnet; A second inner surface opposed to the second main side surface of the magnet; And A first positioning portion protruding from the second inner surface and opposed to the first sub-side surface of the magnet, The number of overlapping sheets of the sheet located between the first sub-side surface of the magnet and the first positioning portion of the magnet hole is greater than the number of overlapping sheets of the sheet located between the first main side surface of the magnet and the first inner surface of the magnet hole.

2. The rotor according to claim 1, wherein: The number of overlapping sheets of the sheet located between the first sub-side surface of the magnet and the first positioning portion of the magnet hole is 2 sheets, The number of overlapping sheets of the sheet located between the first main side surface of the magnet and the first inner surface of the magnet hole is 1 sheet.

3. The rotor according to claim 1, wherein: The magnet hole further has a second positioning portion protruding from the second inner surface and opposed to the second sub-side surface of the magnet, The number of overlapping sheets of the sheet located between the second sub-side surface of the magnet and the second positioning portion of the magnet hole is greater than the number of overlapping sheets of the sheet located between the first main side surface of the magnet and the first inner surface of the magnet hole.

4. The rotor according to claim 3, wherein: The number of overlapping sheets of the sheet located between the second sub-side surface of the magnet and the second positioning portion of the magnet hole is 2 sheets, The number of overlapping sheets of the sheet located between the first main side surface of the magnet and the first inner surface of the magnet hole is 1 sheet.

5. The rotor according to claim 3, wherein: The number of overlapping sheets of the sheet located between the second main side surface of the magnet and the second inner surface of the magnet hole is greater than the number of overlapping sheets of the sheet located between the first main side surface of the magnet and the first inner surface of the magnet hole.

6. The rotor according to claim 5, wherein: The sheet is composed of a single sheet-like member, One end of the initial coil of the single sheet-like component is located on one of the first secondary side and the second secondary side of the magnet. One end of the final coil of the single sheet-like component is located on the other of the first secondary side and the second secondary side of the magnet.

7. The rotor according to claim 1, wherein: The magnet hole further has at least one riveting portion that protrudes from the second inner surface and abuts against the second main side of the magnet via the sheet. The number of overlapping sheets of the sheet located between the second main side of the magnet and the riveting portion of the magnet hole is greater than the number of overlapping sheets of the sheet located between the first main side of the magnet and the first inner surface of the magnet hole.

8. The rotor according to claim 7, wherein: The number of overlapping sheets of the sheet located between the second main side of the magnet and the riveting portion of the magnet hole is equal to the number of overlapping sheets of the sheet located between the first secondary side of the magnet and the first positioning portion of the magnet hole.

9. The rotor according to claim 1, wherein: At least a part of the sheet is made of a foaming material.

10. The rotor according to claim 1, wherein: At least a part of the sheet is made of an insulating material.

11. The rotor according to claim 1, wherein: At least a part of the sheet is made of an adhesive material.

12. The rotor according to claim 1, wherein: A filling material is filled in at least a part of the magnet hole outside the sheet.

13. A rotor, which is a rotor of an electric motor, is characterized in that, Comprising: A rotor core having a magnet hole extending along an axial direction parallel to the rotation axis of the rotor; A magnet inserted into the magnet hole and having a plurality of sides extending along the axial direction; And A sheet wound around the plurality of sides of the magnet, The plurality of sides of the magnet have: A first main side having a first magnetic pole and facing radially outward; A second main side having a second magnetic pole and located on the side opposite to the first main side; A first secondary side extending between the first main side and the second main side; And A second secondary side extending between the first main side and the second main side and located on the side opposite to the first secondary side, The magnet hole has: A first inner surface facing the first main side of the magnet; A second inner surface facing the second main side of the magnet; And A riveting portion that protrudes from the second inner surface and abuts against the second main side of the magnet via the sheet, The number of overlapping sheets of the sheet located between the second main side of the magnet and the riveting portion of the magnet hole is greater than the number of overlapping sheets of the sheet located between the first main side of the magnet and the first inner surface of the magnet hole.

14. The rotor according to claim 13, wherein: At least a part of the magnet holes on the outer side of the sheet is filled with a filling material.

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