rotor

Abstract

To protect a magnet from a protrusion provided in a magnet hole while suppressing influence on magnetic characteristics of a rotor.SOLUTION: A rotor of an electric motor includes a rotor core, a magnet, and a sheet. A plurality of side surfaces of the magnet include: a first major side surface having a first magnetic pole and oriented radially outward; a second major side surface having a second magnetic pole and located opposite the first major side surface; a first minor side surface extending between the first major side surface and the second major side surface; and a second minor side surface extending between the first major side surface and the second major side surface and located opposite the first minor side surface. A magnet hole has a first inner surface facing the first major side surface of the magnet, a second inner surface facing the second major side surface of the magnet, and a first positioning portion protruding from the second inner surface and facing the first minor side surface of the magnet. The number of overlapping sheets located between the first minor surface of the magnet and the first positioning portion of the magnet hole is larger than those located between the first main side surface of the magnet and the first inner surface of the magnet hole.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Patent Document 1 describes a rotor. 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 multiple 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 radially outward, and a second main side surface having a second magnetic pole and positioned opposite the first main side surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-077086 Summary of the Invention [Problem to be solved by the invention]

[0004] In rotors like the one described above, a technique for positioning or fixing magnets by providing protrusions on the inner surface of the magnet holes is known. Such protrusions may locally contact the magnets, potentially causing excessive stress on the magnets. To avoid this, it is conceivable to wrap multiple layers of sheet around the sides of the magnets. However, if the sides of the magnets are covered with multiple layers of sheet, the multiple layers act as a barrier to magnetic flux, resulting in a deterioration in the magnetic properties of the rotor.

[0005] In view of the above, the present specification provides a technique that can protect magnets from protrusions provided in magnet holes while suppressing the influence on the magnetic properties of the rotor. [Means for solving the problem]

[0006] The technology disclosed in this specification is embodied in a rotor for an electric motor. The rotor includes a rotor core having a magnet hole extending in an axial direction parallel to the rotor's rotation axis, a magnet inserted in the magnet hole and having multiple side surfaces extending in the axial direction, and a sheet wrapped around the multiple side surfaces of the magnet. The multiple side surfaces of the magnet include a first major side surface having a first magnetic pole and facing radially outward, a second major side surface having a second magnetic pole and located opposite the first major side surface, a first minor side surface extending between the first major side surface and the second major side surface, and a second minor side surface extending between the first major side surface and the second major side surface and located opposite the first minor side surface. The magnet hole has a first inner surface facing the first major side surface of the magnet, a second inner surface facing the second major side surface of the magnet, and a first positioning portion protruding from the second inner surface and facing the first minor side surface of the magnet. The number of overlapping sheets positioned between the first minor side surface of the magnet and the first positioning portion of the magnet hole is greater than the number of overlapping sheets positioned between the first major side surface of the magnet and the first inner surface of the magnet hole.

[0007] In the rotor described above, a first positioning portion is provided on the second inner surface of the magnet hole to position the magnet relative to the magnet hole. The first positioning portion protrudes from the second inner surface of the magnet hole and faces the first minor side surface of the magnet. Therefore, it is expected that the first positioning portion of the magnet hole will locally abut against the first minor side surface of the magnet. However, a sheet is wrapped around multiple sides of the magnet, including the first minor side surface, and multiple layers of the sheet are interposed between the first minor side surface of the magnet and the first positioning portion of the magnet hole. This effectively protects the first minor side surface of the magnet from abutting against the first positioning portion. On the other hand, the first major side surface, which has a magnetic pole and faces the stator, is covered with only a relatively small number of layers (including one layer) of sheet. This allows the magnetic properties of the rotor to be suppressed while the magnetic properties of the rotor are suppressed. No. 1 The magnet can be protected from the positioning portion.

[0008] In a second aspect, the number of overlapping sheets positioned between the first minor side surface of the magnet and the first positioning portion of the magnet hole in the first aspect may be two. In this case, the number of overlapping sheets positioned between the first major side surface of the magnet and the first inner surface of the magnet hole may be one. However, these overlapping numbers may be larger and can be designed appropriately depending on the material, thickness, etc. of the sheets.

[0009] In a third aspect, in the first or second aspect, the magnet hole may further have a second positioning portion protruding from the second inner surface and facing the second minor side surface of the magnet. In this case, the number of overlapping sheets positioned between the second minor side surface of the magnet and the second positioning portion of the magnet hole may be greater than the number of overlapping sheets positioned between the first major side surface of the magnet and the second inner surface of the magnet hole. In this way, the magnet hole may have multiple positioning portions, and in that case, it is preferable to cover each positioning portion with multiple layers of sheet.

[0010] In a fourth aspect, the number of overlapping sheets positioned between the second minor side surface of the magnet and the second positioning portion of the magnet hole in the third aspect may be two. In this case, the number of overlapping sheets positioned between the first major side surface of the magnet and the first inner surface of the magnet hole may be one. However, these overlapping numbers may be larger and can be designed appropriately depending on the material, thickness, etc. of the sheets.

[0011] In a fifth aspect, in any of the first to fourth aspects, the number of overlapping sheets located between the second main side surface of the magnet and the second inner surface of the magnet hole may be greater than the number of overlapping sheets located between the first main side surface of the magnet and the first inner surface of the magnet hole. With this configuration, the first main side surface facing radially outward is covered with fewer sheets than the second main side surface facing radially inward, thereby suppressing the effect on the magnetic properties of the rotor.

[0012] In a sixth aspect, in any of the first to fifth aspects, the sheet may be formed from a single sheet material. In this case, one end of the winding start of the single sheet material may be located on one of the first minor side surface and the second minor side surface of the magnet. Also, one end of the winding end of the single sheet material may be located on the other of the first minor side surface and the second minor side surface of the magnet. With this configuration, the end of the sheet is not located on the first major side surface and the second major side surface that have the magnetic poles, so that the influence on the magnetic characteristics of the rotor can be suppressed.

[0013] In a seventh aspect, in any of the first to sixth aspects, the magnet hole may further have at least one crimped portion protruding from the second inner surface and abutting against the second main side surface of the magnet via a sheet. In this case, the number of overlapping sheets located between the second main side surface of the magnet and the crimped portion of the magnet hole may be greater than the number of overlapping sheets located between the first main side surface of the magnet and the first inner surface of the magnet hole.

[0014] In the above-described embodiment, a crimped portion is provided on the second inner surface of the magnet hole to secure the magnet to the magnet hole. The crimped portion protrudes from the second inner surface of the magnet hole, but multiple layers of sheet are interposed between the crimped portion of the magnet hole and the second main side surface of the magnet, so the second main side surface of the magnet is effectively protected from contact with the crimped portion of the magnet hole. Meanwhile, the first main side surface, which has the magnetic poles and faces the stator, is covered with a relatively small number of layers (including one layer) of sheet. This makes it possible to protect the magnet from the crimped portion provided in the magnet hole while suppressing any effect on the magnetic properties of the rotor.

[0015] In an eighth aspect, in the seventh aspect, the number of overlapping sheets located between the second major side surface of the magnet and the crimped portion of the magnet hole may be equal to the number of overlapping sheets located between the first minor side surface of the magnet and the first positioning portion of the magnet hole. However, in other embodiments, the number of overlapping sheets located between the second major side surface of the magnet and the crimped portion of the magnet hole may be less or more than the number of overlapping sheets located between the first minor side surface of the magnet and the first positioning portion of the magnet hole.

[0016] In a ninth aspect, in any of the first to eighth aspects, the sheet may be at least partially made of a foam material. With this configuration, the space between the magnet and the magnet hole is filled with the foam material without any gaps, stabilizing the position of the magnet. Furthermore, since the foam material has high flexibility, it can effectively protect each side of the magnet from protruding parts such as the first positioning part, the second positioning part, and / or the crimped part.

[0017] In a tenth aspect, in any one of the first to ninth aspects, the sheet may be at least partially made of an insulating material. With this configuration, it is possible to electrically insulate the magnet from the magnet bore, and to suppress losses due to eddy currents in the rotor.

[0018] In an eleventh aspect, in any one of the first to tenth aspects, the sheet may be at least partially made of an adhesive material, so that the magnets can be fixed to the magnet holes by the adhesive material of the sheet.

[0019] In a twelfth aspect, in any one of the first to eleventh aspects, a filler may be filled in at least a portion of the magnet holes on the outside of the sheet. With this configuration, the filler can fix the magnets to the magnet holes.

[0020] The technology disclosed in this specification is embodied in a rotor for another electric motor. This rotor includes a rotor core having a magnet hole extending in an axial direction parallel to the rotation axis of the rotor, a magnet inserted in the magnet hole and having multiple side surfaces extending in the axial direction, and a sheet wrapped around the multiple side surfaces of the magnet. The multiple side surfaces of the magnet include a first major side surface having a first magnetic pole and facing radially outward, a second major side surface having a second magnetic pole and located opposite the first major side surface, a first minor side surface extending between the first major side surface and the second major side surface, and a second minor side surface extending between the first major side surface and the second major side surface and located opposite the first minor side surface. The magnet hole includes a first inner surface facing the first major side surface of the magnet, a second inner surface facing the second major side surface of the magnet, and a sheet protruding from the second inner surface to form the multiple side surfaces of the magnet. 2nd main side and a crimped portion that abuts, via the sheet, against the second main side surface of the magnet. The number of overlapping sheets positioned between the second main side surface of the magnet and the crimped portion of the magnet hole is greater than the number of overlapping sheets positioned between the first main side surface of the magnet and the first inner surface of the magnet hole.

[0021] In the rotor described above, a crimped portion is provided on the second inner surface of the magnet hole to secure the magnet to the magnet hole. The crimped portion protrudes from the second inner surface of the magnet hole, but multiple layers of sheet are interposed between the crimped portion of the magnet hole and the second main side surface of the magnet, so the second main side surface of the magnet is effectively protected from contact with the crimped portion of the magnet hole. Meanwhile, the first main side surface, which has the magnetic poles and faces the stator, is covered with a relatively small number of layers (including one layer) of sheet. This makes it possible to protect the magnet from the crimped portion provided in the magnet hole while suppressing the effect on the magnetic properties of the rotor. [Brief explanation of the drawings]

[0022] [Figure 1]1 is a schematic diagram of an electric motor 100 employing a rotor 10 according to a first embodiment, viewed from a direction perpendicular to a rotation axis R. Note that a cross section of the rotor 10 is shown for a portion on the left side of the rotation axis R on the paper. [Figure 2] 2 is a cross-sectional view taken along line II-II in FIG. 1, showing one end face of rotor core 14 in the axial direction. [Figure 3] An enlarged view of part III in Figure 2. [Figure 4] FIG. 4 is an enlarged view corresponding to FIG. 3, showing the configuration of a rotor 110 according to a second embodiment. [Figure 5] FIG. 4 is an enlarged view corresponding to FIG. 3, showing the configuration of a rotor 210 according to a third embodiment. [Figure 6] FIG. 10 is an enlarged view corresponding to FIG. 3, showing the configuration of a rotor 310 according to a fourth embodiment. [Figure 7] FIG. 10 is an enlarged view corresponding to FIG. 3, showing the configuration of a rotor 410 according to a fifth embodiment. [Figure 8] FIG. 10 is an enlarged view corresponding to FIG. 3, showing the configuration of a rotor 510 according to a sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0023] (Example 1) A rotor 10 of Example 1 will be described with reference to the drawings. The rotor 10 of this example is employed in an electric motor 100. The electric motor 100 includes the rotor 10, a stator 102, and a housing 104. The housing 104 is a housing 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 by the housing 104 so as to be rotatable about a rotation axis R. Although not particularly limited, the housing 104 may further house a power transmission mechanism (not shown) such as a reduction mechanism or a differential mechanism.

[0024] The stator 102 generally has a cylindrical shape with the rotation axis R as its central axis. The stator 102 is disposed radially outside 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. As an example, the stator core 102a in this embodiment is made by laminating multiple electromagnetic steel plates. The stator coil 102b is wound around the stator core 102a and is configured to magnetize the stator core 102a. As an example, the electric motor 100 in this 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 However, the specific configuration of the stator 102 is not particularly limited.

[0025] As shown in FIGS. 1 and 2 , the rotor 10 includes a shaft 12 and a rotor core 14. The shaft 12 is disposed so that its central axis coincides with the rotation axis R. The shaft 12 is made of a metal such as stainless steel. The rotor core 14 is located radially outward 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. As an example, the rotor core 14 in this embodiment is formed by laminating multiple electromagnetic steel plates. A through hole 14a is provided in 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 and is prohibited from rotating relative to the shaft 12.

[0026] As shown in FIGS. 1 and 2, 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 on the outer periphery of the rotor core 14 and are regularly arranged along the circumferential direction. Each of the magnet holes 16a, 16b extends in an 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 slot shape extending along the circumferential direction, with the longitudinal axis of the slot shape forming an angle with respect to the circumferential direction. The plurality of magnet holes 16a, 16b includes a plurality of pairs of first magnet holes 16a and a plurality of pairs of second magnet holes 16b. Each pair of first magnet holes 16a is arranged symmetrically 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 arranged symmetrically in the circumferential direction of the rotor core 14. Each pair of second magnet holes 16b is located radially inward of the corresponding pair of first magnet holes 16a. Two magnets 18 are inserted into each second magnet hole 16b. Each magnet 18 has a substantially rectangular parallelepiped shape extending in an axial direction parallel to the rotation axis R of the rotor 10. Although not particularly limited, each magnet 18 is a permanent magnet.

[0027] Next, the configuration relating to one first magnet hole 16a and the magnet 18 inserted therein will be described with reference to Figure 3. The configuration described below is also similarly employed for the other first magnet holes 16a and the magnets 18 inserted therein, and for the second magnet hole 16b and the two magnets 18 inserted therein.

[0028] As shown in FIG. 3 , the magnet 18 has multiple side surfaces 20, 22, 24, and 26 extending in the axial direction. The multiple side surfaces 20, 22, 24, and 26 include a first major side surface 20, a second major side surface 22, a first minor side surface 24, and a second minor side surface 26. The first major side surface 20 has a first magnetic pole and faces radially outward. The fact that the first major side surface 20 faces radially outward means that the normal vector of the first major side surface 20 includes at least a component facing radially outward. In other words, each of the multiple magnets 18 does not necessarily have to be perpendicular to the radial direction and may be inclined relative to the radial direction. The first magnetic pole is either a north pole or a south pole. In the electric motor 100, the first major side surface 20 of the rotor 10 faces the stator 102. The second major side surface 22 has a second magnetic pole and is located on the opposite side of the first major side surface 20. The second magnetic pole is the opposite pole to the first magnetic pole and is either a north pole or a south pole. The first minor-side surface 24 extends between the first major-side surface 20 and the second major-side surface 22. The second minor-side surface 26 extends between the first major-side surface 20 and the second major-side surface 22 and is located on the opposite side of the first minor-side surface 24. When the rotor 10 is viewed from a direction parallel to the rotation axis R, the first major-side surface 20, the first minor-side surface 24, the second major-side surface 22, and the second minor-side surface 26 are arranged in series in that order. The areas of the first major-side surface 20 and the second major-side surface 22 are larger than the areas of the first minor-side surface 24 and the second minor-side surface 26.

[0029] As shown in FIG. 3 , 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 major side surface 20 of the magnet 18. The second inner surface 30 faces the second major side surface 22 of the magnet 18. The second inner surface 30 is provided with a first positioning portion 32 and a second positioning portion 34. These positioning portions 32, 34 are portions that position 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 minor side surface 24 of the magnet 18. The second positioning portion 34 protrudes from the second inner surface 30 and faces the second minor side surface 26 of the magnet 18. Because the second inner surface 30 of the first magnet hole 16a is angled with respect to the circumferential direction, the first positioning portion 32 is positioned further radially than the second positioning portion 34. Inside It is located on the side.

[0030] In the rotor 10 described above, positioning portions 32, 34 are provided on the second inner surface 30 of the first magnet hole 16a to position the magnet 18 relative to the first magnet hole 16a. The positioning portions 32, 34 protrude from the second inner surface 30 of the first magnet hole 16a and face the minor side surfaces 24, 26 of the magnet 18. Therefore, it is expected that the positioning portions 32, 34 of the first magnet hole 16a will locally abut against the minor side surfaces 24, 26 of the magnet 18.

[0031] In regard to the above, as shown in FIG. 3 , the rotor 10 further includes a sheet 36. In this embodiment, the sheet 36 is formed from a single sheet material. The sheet 36 is wrapped around the multiple side surfaces 20, 22, 24, and 26 of the magnet 18. In one example, the starting end 36a of the sheet 36 is located on the first minor side surface 24 of the magnet 18, and the ending end 36b of the sheet 36 is located on the second minor side surface 26 of the magnet 18. For example, in the manufacturing process of the rotor 10, the sheet 36 is wound around the magnet 18 with the end 36a of the sheet 36 located on the first minor side surface 24 of the magnet 18. At this time, the sheet 36 sequentially covers the second major side surface 22, the second minor side surface 26, and the first major side surface 20. When the sheet 36 is again located on the second minor side surface 26 of the magnet 18, the sheet 36 is cut. As a result, the winding start end 36a of the sheet 36 is located on the first minor side surface 24 of the magnet 18, and the winding end end 36b of the sheet 36 is located on the second minor side surface 26 of the magnet 18. In other words, the winding start end 36a of the sheet 36 is the end located in the innermost layer of the sheet 36 wound around the magnet 18, and the winding end end 36b of the sheet 36 is the end located in the outermost layer of the sheet 36 wound around the magnet 18.

[0032] In this embodiment, the number of overlapping sheets 36 positioned between the first minor 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 36 positioned between the first major side surface 20 of the magnet 18 and the first inner surface 28 of the first magnet hole 16a is one. Also, the number of overlapping sheets 36 positioned between the second minor side surface 26 of the magnet 18 and the second positioning portion 34 of the first magnet hole 16a is two. In addition, Magnet 18 No. 2 Main side 22 The number of overlapping sheets 36 positioned between the first inner surface 30 of the first magnet hole 16a and the second inner surface 30 of the first magnet hole 16a is two.

[0033] With this configuration, the secondary side surfaces 24, 26 of the magnet 18 are effectively protected from contact with the positioning portions 32, 34. On the other hand, the first primary side surface 20, which has the magnetic poles and faces the stator 102, is covered with only a relatively small number of layers (one layer in this embodiment) of sheet 36. This makes it possible to protect the magnet 18 from the positioning portions 32, 34 provided in the first magnet hole 16a while suppressing the effect on the magnetic properties of the rotor 10.

[0034] Although not particularly limited, in the rotor 10 described above, as shown in FIG. 3, the number of overlapping sheets 36 (two in this embodiment) positioned between the second main side surface 22 of the magnet 18 and the second inner surface 30 of the first magnet hole 16a is a This is greater than the number of overlapping sheets 36 (one sheet in this embodiment) positioned between the first inner surface 28 and the first main side surface 20. With this configuration, the first main side surface 20 facing radially outward is covered with fewer sheets 36 than the second main side surface 22 facing radially inward, thereby suppressing the effect on the magnetic characteristics of the rotor 10.

[0035] In this embodiment, two sheets 36 are stacked between the minor side surfaces 24, 26 of the magnet 18 and the positioning portions 32, 34 of the first magnet hole 16a, and one sheet 36 is stacked between the first major side surface 20 of the magnet 18 and the first inner surface 28 of the first magnet hole 16a. However, in other embodiments, these numbers may be greater. In this case, it is sufficient that the number of sheets 36 stacked between the minor side surfaces 24, 26 of the magnet 18 and the positioning portions 32, 34 of the first magnet hole 16a is greater than the number of sheets 36 stacked between the first major 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 located between the first minor side surface 24 of the magnet 18 and the first positioning portion 32 of the first magnet hole 16a may be greater or less than the number of overlapping sheets 36 located between the second minor side surface 26 of the magnet 18 and the second positioning portion 34 of the first magnet hole 16a.

[0036] In this embodiment, first magnet hole 16a is provided with two positioning portions 32, 34. However, the number of positioning portions 32, 34 provided in first magnet hole 16a is not particularly limited. In another embodiment, first magnet hole 16a may be provided with one positioning portion, in which case, the positioning portion may be covered with a multi-layer sheet 36. Alternatively, in yet another embodiment, first magnet hole 16a may be provided with three or more positioning portions, in which case, each positioning portion may be covered with a multi-layer sheet 36.

[0037] In this embodiment, the winding start end 36a of the sheet 36 is located on the first minor side surface 24 of the magnet 18, and the winding end 36b of the sheet 36 is located on the second minor side surface 26 of the magnet 18. With this configuration, the winding end 36a, 36b of the sheet 36 are not located on the first major side surface 20 and the second major side surface 22, which have magnetic poles, thereby suppressing the influence on the magnetic properties of the rotor 10. Note that, in another embodiment, the winding start end 36a of the sheet 36 may be located on the second minor side surface 26 of the magnet 18, and the winding end end 36b of the sheet 36 may be located on the first minor side surface 24 of the magnet 18. Furthermore, the sheet 36 does not necessarily have to be composed of a single sheet material, but may be composed of a combination of multiple sheet materials. For example, the sheet 36 may be composed of a first sheet covering the multiple sides 20, 22, 24, and 26 of the magnet 18 and a second sheet further covering the second major side surface 22 covered by the first sheet.

[0038] Although not particularly limited, in this embodiment, sheet 36 is at least partially made of a foam material. With this configuration, the space between magnet 18 and first magnet hole 16a is filled with foam material without any gaps, stabilizing the position of magnet 18. In addition, because foam material has high flexibility, it can effectively protect each side surface 20, 22, 24, 26 of magnet 18 from protruding parts such as positioning portions 32, 34.

[0039] Additionally or alternatively, the sheet 36 in this embodiment is at least partially made of an insulating material. This configuration provides electrical insulation between the magnet 18 and the first magnet hole 16a, thereby suppressing losses due to eddy currents in the rotor 10.

[0040] Additionally or alternatively, sheet 36 in this embodiment is at least partially made of an adhesive material, which allows magnet 18 to be fixed to first magnet hole 16a by the adhesive material of sheet 36.

[0041] In this embodiment, each pair of second magnet holes 16b is located radially inward relative to the corresponding pair of first magnet holes 16a, and a magnet 18 is inserted into each of the magnet holes 16a, 16b. Therefore, the multiple magnets 18 include magnets 18 inserted into the first magnet holes 16a and arranged radially outward, and magnets 18 inserted into the second magnet holes 16b and arranged radially inward. That is, in this embodiment, the multiple magnets 18 are arranged in two layers in the radial direction. However, the multiple magnets 18 do not necessarily have to be arranged in two layers in the radial direction. In other embodiments, the multiple magnets 18 may be arranged in one layer in the radial direction, or in three or more layers. Furthermore, the multiple magnets 18 may be arranged repeatedly in a V-shape in each layer.

[0042] In this embodiment, each magnet 18 has a generally rectangular parallelepiped shape extending in an axial direction parallel to the rotation axis R of the rotor 10. However, each magnet 18 does not necessarily have to have a generally rectangular parallelepiped shape. For example, in another embodiment, each magnet 18 may have a plate shape in which the first main side surface 20 and the second main side surface 22 are curved. Furthermore, such curved magnets may be arranged in two or more layers in the radial direction.

[0043] (Example 2) A rotor 110 of Example 2 will be described with reference to Figure 4. As shown in Figure 4, the rotor 110 of Example 2 is different from the rotor 10 of Example 1 in that a crimped portion 38 is provided in the first magnet hole 16a. The remaining configuration is the same as the rotor 10 of Example 1, so a duplicated description will be omitted here. The configuration related to the first magnet hole 16a described in this example is also used in the other first magnet holes 16a and second magnet holes 16b.

[0044] As shown in FIG. 4, the crimped 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) located between the second main side surface 22 of the magnet 18 and the crimped portion 38 of the first magnet hole 16a is greater than the number of overlapping sheets 36 (one layer in this embodiment) located between the first main side surface 20 of the magnet 18 and the first inner surface 28 of the first magnet hole 16a. The number and arrangement of the crimped portions 38 are not particularly limited, as long as the crimped 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, the rotor in this embodiment 110 In the rotor, the caulking portion 38 is formed by stamping. 110 On the end face in the axial direction, there is a stamped mark 40 near the crimped portion 38.

[0045] In the rotor 110 of the second embodiment, a crimped portion 38 is provided on the second inner surface 30 of the first magnet hole 16a to fix the magnet 18 to the first magnet hole 16a. The crimped portion 38 protrudes from the second inner surface 30 of the first magnet hole 16a, but multiple layers of sheet 36 are interposed between the crimped portion 38 of the first magnet hole 16a and the second main side surface 22 of the magnet 18, so the second main side surface 22 of the magnet 18 is effectively protected from contact with the crimped portion 38 of the first magnet hole 16a. On the other hand, the first main side surface 20, which has magnetic poles and faces the stator 102, is covered with a relatively small number of layers (including one layer) of sheet 36. This allows the rotor 110 This can protect the magnet 18 from the crimped portion 38 provided in the first magnet hole 16a while suppressing the influence on the magnetic characteristics of the magnet 18.

[0046] As mentioned above, the configuration of the first magnet hole 16a described in Example 2 is also employed in the other first magnet holes 16a and the multiple second magnet holes 16b. That is, in these magnet holes 16a, 16b as well, a crimped portion 38 is provided on the second inner surface 30. The number of overlapping sheets 36 located between the second main side surface 22 of the magnet 18 and the crimped portion 38 of the magnet holes 16a, 16b is greater than the number of overlapping sheets 36 located between the first main side surface 20 of the magnet 18 and the first inner surface 28 of the magnet holes 16a, 16b.

[0047] Although not particularly limited, in rotor 110 of Example 2, the number of overlapping sheets 36 located between second major side surface 22 of magnet 18 and crimped portion 38 of first magnet hole 16a is equal to the number of overlapping sheets 36 located between first minor side surface 24 of magnet 18 and positioning portions 32, 34 of first magnet hole 16a. However, in other embodiments, the number of overlapping sheets 36 located between second major side surface 22 of magnet 18 and crimped portion 38 of first magnet hole 16a may be less or more than the number of overlapping sheets 36 located between first minor side surface 24 of magnet 18 and positioning portions 32, 34 of first magnet hole 16a.

[0048] (Third embodiment) A rotor 210 of a third embodiment will be described with reference to Fig. 5. As shown in Fig. 5, the rotor 210 of the third embodiment differs from the rotor 10 of the first embodiment in that the first magnet hole 16a is filled with a filler 42. The remaining configuration is the same as the rotor 10 of the first embodiment, so a duplicated description will be omitted here. Although not shown, the same filler 42 is also filled in the other first magnet holes 16a and second magnet holes 16b.

[0049] As shown in FIG. 5 , the filler 42 fills the gap between the first magnet hole 16a and the sheet 36 on the outside of the sheet 36. With this configuration, the magnet 18 is fixed to the first magnet hole 16a. However, the filler 42 does not necessarily have to completely fill the gap between the first magnet hole 16a and the sheet 36. The filler 42 may fill at least a portion of the gap. The material constituting the filler 42 is not particularly limited. As an example, the material constituting the filler 42 may be an electrically insulating material and a magnetically non-magnetic material. As an example, the filler 42 in this embodiment is a resin material, and in particular, a thermosetting resin material.

[0050] As shown in FIG. 5 , the area of ​​the first magnet hole 16a filled with the filler 42 is mainly located 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 first minor side surface 24 side of the first magnet hole 16a and a second region located on the second minor side surface 26 side of the first magnet hole 16a. The first region contains the winding start end 36a of the sheet 36, which does not directly contact the filler 42. The second region contains the winding end 36b of the sheet 36, which directly contacts the filler 42. Therefore, when filling the gap between the first magnet hole 16a and the magnet 18 with the filler 42 during the manufacture of the rotor 210, it is preferable to fill the filler 42 starting from the first region where the winding start end 36a is located. This makes it difficult for the filler 42 to penetrate inside the sheet 36, and prevents the sheet 36 from being bent or broken.

[0051] (Fourth Example) A rotor 310 of the fourth example will be described with reference to FIG. 6. As shown in FIG. 6, the rotor 310 of the fourth example differs from the rotor 110 of the second example in that the first magnet hole 16a is filled with a filler 42. The remaining configuration is the same as that of the rotor 110 of the second example, and therefore a duplicated description will be omitted here. Although not shown, similar filler 42 is also filled in the other first magnet holes 16a and second magnet holes 16b. The configuration, action, and effect of the filler 42 in this example are similar to those of the filler 42 in the third example, and therefore a duplicated description will be omitted here.

[0052] (Fifth Embodiment) A rotor 410 of the fifth embodiment will be described with reference to FIG. 7. As shown in FIG. 7, the rotor 410 of the fifth embodiment is different from the rotor 10 of the first embodiment in that the first magnet hole 16a is provided with a crimped portion 38 instead of the positioning portions 32 and 34. In other words, the rotor 410 of the fifth embodiment is the rotor 110 of the second embodiment from which the positioning portions 32 and 34 have been removed. Similarly, the other first magnet holes 16a and the second magnet hole 16b are not provided with the positioning portions 32 and 34, and in this respect the rotor 410 differs from the rotor 110 of the second embodiment. The remaining configuration is the same as that of the rotor 110 of the second embodiment, and therefore a redundant description will be omitted here.

[0053] (Sixth Example) A rotor 510 of the sixth example will be described with reference to Fig. 8. As shown in Fig. 8, the rotor 510 of the sixth example differs from the rotor 410 of the fifth example in that the first magnet hole 16a is filled with a filler 42. Although not shown, similar fillers 42 are also filled in the other first magnet holes 16a and second magnet holes 16b. The configuration, action, and effect of the filler 42 in this example are similar to those of the filler 42 in the third and fourth examples, and therefore a redundant description will be omitted here.

[0054] Although several specific examples have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and alterations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility either alone or in combination. [Explanation of symbols]

[0055] 10: rotor, 12: shaft, 14: rotor core, 16a, 16b: magnet hole, 18: magnet, 20: first main side surface, 22: second main side surface, 24: first minor side surface, 26: second minor side surface, 28: first inner surface, 30: second inner surface, 32, 34: positioning portion, 36: seat, 38: caulking portion, 40: stamping mark, 42: filler material, 100: electric motor, 102: stator, 104: housing, R: rotating shaft

Claims

1. A rotor of an electric motor, a rotor core having magnet holes 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; a sheet wrapped around the plurality of sides of the magnet; Equipped with The plurality of side surfaces of the magnet include a first major side surface having a first magnetic pole and facing radially outward, a second major side surface having a second magnetic pole and located opposite the first major side surface, a first minor side surface extending between the first major side surface and the second major side surface, and a second minor side surface extending between the first major side surface and the second major side surface and located opposite the first minor side surface, the magnet hole has a first inner surface facing the first major side surface of the magnet, a second inner surface facing the second major side surface of the magnet, and a first positioning portion protruding from the second inner surface and facing the first minor side surface of the magnet, the number of overlapping sheets positioned between the first minor side surface of the magnet and the first positioning portion of the magnet hole is greater than the number of overlapping sheets positioned between the first major side surface of the magnet and the first inner surface of the magnet hole, the magnet hole further includes a second positioning portion protruding from the second inner surface and facing the second minor side surface of the magnet; the number of overlapping sheets positioned between the second minor side surface of the magnet and the second positioning portion of the magnet hole is greater than the number of overlapping sheets positioned between the first major side surface of the magnet and the first inner surface of the magnet hole, the number of overlapping sheets positioned 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 positioned between the first main side surface of the magnet and the first inner surface of the magnet hole; Rotor.

2. the number of the overlapping sheets positioned between the first minor side surface of the magnet and the first positioning portion of the magnet hole is two, The rotor according to claim 1 , wherein the number of overlapping sheets located between the first main side surface of the magnet and the first inner surface of the magnet hole is one.

3. the number of the overlapping sheets positioned between the second minor side surface of the magnet and the second positioning portion of the magnet hole is two, The rotor according to claim 1 , wherein the number of overlapping sheets located between the first main side surface of the magnet and the first inner surface of the magnet hole is one.

4. the sheet is made of a single sheet material; One end of the start of winding of the single sheet material is located on one of the first minor side surface and the second minor side surface of the magnet, 2. The rotor according to claim 1, wherein one end of the winding end of the single sheet material is located on the other of the first minor side surface and the second minor side surface of the magnet.

5. the magnet hole further has at least one crimping portion protruding from the second inner surface and abutting against the second main side surface of the magnet via the sheet; 2. The rotor of claim 1, wherein the number of overlapping sheets positioned between the second main side surface of the magnet and the crimped portion of the magnet hole is greater than the number of overlapping sheets positioned between the first main side surface of the magnet and the first inner surface of the magnet hole.

6. 6. The rotor of claim 5, wherein the number of overlapping sheets positioned between the second main side surface of the magnet and the crimped portion of the magnet hole is equal to the number of overlapping sheets positioned between the first minor side surface of the magnet and the first positioning portion of the magnet hole.

7. The rotor of claim 1 , wherein the sheet is constructed at least in part from a foam material.

8. The rotor of claim 1 , wherein the sheet is at least partially constructed using an insulating material.

9. The rotor of claim 1 , wherein the sheet is constructed at least in part from an adhesive material.

10. The rotor of claim 1 , wherein, outside the sheets, at least a portion of the magnet holes are filled with a filler material.

11. A rotor of an electric motor, a rotor core having magnet holes 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; a sheet wrapped around a plurality of sides of the magnet; Equipped with The plurality of side surfaces of the magnet include a first major side surface having a first magnetic pole and facing radially outward, a second major side surface having a second magnetic pole and located opposite the first major side surface, a first minor side surface extending between the first major side surface and the second major side surface, and a second minor side surface extending between the first major side surface and the second major side surface and located opposite the first minor side surface, the magnet hole has 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 crimped portion protruding from the second inner surface and abutting against the second main side surface of the magnet via the sheet, the number of overlapping sheets positioned between the second main side surface of the magnet and the crimped portion of the magnet hole is greater than the number of overlapping sheets positioned between the first main side surface of the magnet and the first inner surface of the magnet hole; Rotor.

12. The rotor of claim 11 , wherein, outside the sheets, at least a portion of the magnet holes are filled with a filler material.

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