WO2020059513A1 - Rotor and electric motor using same - Google Patents

Rotor and electric motor using same Download PDF

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Publication number
WO2020059513A1
WO2020059513A1 PCT/JP2019/034934 JP2019034934W WO2020059513A1 WO 2020059513 A1 WO2020059513 A1 WO 2020059513A1 JP 2019034934 W JP2019034934 W JP 2019034934W WO 2020059513 A1 WO2020059513 A1 WO 2020059513A1
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WO
WIPO (PCT)
Prior art keywords
magnet
rotor
rotor core
magnets
insertion holes
Prior art date
Application number
PCT/JP2019/034934
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French (fr)
Japanese (ja)
Inventor
和哉 片山
慎一 堤
近藤　憲司
Original Assignee
パナソニックＩｐマネジメント株式会社
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Application filed by パナソニックＩｐマネジメント株式会社 filed Critical パナソニックＩｐマネジメント株式会社
Publication of WO2020059513A1 publication Critical patent/WO2020059513A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets

Definitions

  • the present invention relates to a rotor and an electric motor using the same.
  • the invention particularly relates to a rotor having a permanent magnet disposed therein.
  • an IPM (Internal Permanent Magnet) motor having a structure in which a permanent magnet (hereinafter, simply referred to as a magnet) is embedded in a rotor core.
  • An IPM motor can use higher reluctance torque than a SPM (Surface Permanent Magnet) motor in which a magnet is arranged on the surface of a rotor core, so that a higher rotation torque can be obtained.
  • a magnet insertion hole having a V-shape or a U-shape as viewed from above is provided in the rotor core in order to dispose a magnet at a high volume density with respect to the rotor core having the same volume.
  • a configuration in which a magnet formed so as to have an outer shape along the inner peripheral surface of a hole is embedded.
  • Patent Document 2 discloses that a magnet material is injected into a magnet insertion hole to form a magnet while applying a magnetic field, while a magnetized magnet is disposed in the magnet insertion hole on the side near the axis of the rotor core. A configuration that prevents variations in the magnetic force of the entire magnet by providing the magnet is disclosed.
  • An object of the present invention is to provide a rotor and a motor using the same, which can improve the utilization efficiency of the magnet and can easily arrange the magnet in the rotor core.
  • a rotor according to the present invention includes a rotating shaft, a rotor core having a plurality of magnet insertion holes provided at predetermined intervals in a circumferential direction along an outer periphery, and a plurality of magnets.
  • Each of the plurality of magnets is composed of a plurality of divided magnets that are stacked and embedded in the axial direction in which the rotation axis extends.
  • Each of the plurality of magnet insertion holes is provided so as to extend from the outer peripheral side of the rotor core to the axis side of the rotor core in a top view, and the radial length of the rotor core in the radial direction is the circumferential direction. Has a first portion that is longer than the length.
  • An insulating layer is provided between the plurality of divided magnets adjacent in the axial direction.
  • the eddy current generated in each of the divided magnets at the time of magnetization can be reduced, and a decrease in the magnetization rate of the magnet near the axis of the rotor core can be suppressed.
  • the utilization efficiency of the magnet in the rotor can be increased.
  • the magnet can be easily arranged in the rotor core.
  • the outer shape of one of the plurality of magnets is defined along the inner peripheral surface of one of the plurality of magnet insertion holes when viewed from above.
  • the plurality of magnet insertion holes may be convex toward the axis of the rotor core in a top view.
  • the magnet insertion hole may have a rectangular shape extending from the outer peripheral side of the rotor core toward the axis of the rotor core in a top view.
  • the rotor has a d-axis magnetic flux passage passing through two magnets adjacent in the circumferential direction among a plurality of magnets, and a q-axis passing through a rotor core located radially outside of the plurality of magnets when viewed from above.
  • a magnetic flux path may be formed and have magnetic saliency.
  • another rotor includes a rotating shaft, a rotor core having a plurality of magnet insertion holes provided at predetermined intervals in a circumferential direction along the outer periphery, and a plurality of magnet insertion holes. And a plurality of magnets embedded in each of them.
  • Each of the plurality of magnet insertion holes has a first portion provided to extend from the outer peripheral side of the rotor core to the axial center side of the rotor core in a top view.
  • Each of the plurality of magnets includes a first magnet embedded in the first portion and located on a side closer to the axis of the rotor core, the first magnet being a plurality of divided segments stacked in the axial direction of the rotation axis.
  • Each of the plurality of magnets includes a second magnet embedded in the first portion and located on a side closer to the outer periphery of the rotor core, and a surface area of a side surface of the second magnet is a side surface of one split magnet in the first magnet. Greater than the surface area.
  • the second magnet is provided in contact with the first magnet in a radial direction that is a radial direction of the rotor core with the insulating layer interposed in the plurality of magnet insertion holes.
  • the utilization efficiency of the first magnet can be increased. Further, by making the surface area of the second magnet larger than the surface area of one divided magnet in the first magnet, the degree of demagnetization of the second magnet by the magnetic field from the stator can be reduced. Further, the ratio of the insulating layer in the second magnet can be reduced. For this reason, the magnetic force of the whole magnet can be improved.
  • the outer shape of the portion buried in the first portion of each of the plurality of magnets is defined along the inner peripheral surface of the first portion in a top view.
  • the axial length of the second magnet is substantially equal to the axial length of the plurality of magnet insertion holes.
  • the electric motor according to the present invention includes at least one of the above-described rotors and a stator disposed at a predetermined distance from the rotor.
  • the utilization efficiency of the magnet can be improved, and the magnet can be easily arranged in the rotor core. According to the electric motor of the present invention, a high rotational torque can be obtained.
  • FIG. 2 is a schematic cross-sectional view illustrating a main part of the electric motor according to the first embodiment of the present invention. It is a perspective view showing the magnet of the electric motor concerning Embodiment 1 of the present invention.
  • FIG. 2 is a perspective view illustrating a split magnet of the electric motor according to the first embodiment of the present invention.
  • 4 is a flowchart illustrating an assembling procedure of the rotor of the electric motor according to the first embodiment of the present invention. It is a figure which shows the distribution of the magnetic force line in a stator in the magnetizing process of the assembly procedure of the rotor of the electric motor which concerns on Embodiment 1 of this invention.
  • FIG. 1 is a schematic cross-sectional view illustrating a main part of the electric motor according to the first embodiment of the present invention. It is a perspective view showing the magnet of the electric motor concerning Embodiment 1 of the present invention.
  • FIG. 2 is a perspective view illustrating a split magnet of the electric motor according to the first embodiment of the
  • FIG. 4 is a diagram illustrating a relationship between a radial distance from an outer periphery of a rotor of the electric motor according to the first embodiment of the present invention and a magnetization rate of a magnet.
  • It is a schematic diagram which shows the generation state of the eddy current and the demagnetizing field in the magnet by the presence or absence of the division
  • FIG. 13 is a schematic cross-sectional view showing a rotor according to still another modification.
  • It is a perspective view showing a magnet concerning Embodiment 2 of the present invention.
  • It is a perspective view showing another magnet concerning Embodiment 2 of the present invention.
  • FIG. 1 is a schematic cross-sectional view illustrating a main part of an electric motor according to Embodiment 1 of the present invention.
  • the direction in which the rotating shaft 50 provided on the rotor core 10 extends is referred to as “axial direction”
  • the radial direction of the rotor core 10 is referred to as “radial direction”
  • the outer periphery of the rotor core 10 is referred to as “radial direction”.
  • the directions along are sometimes referred to as “circumferential directions”.
  • the axis of the rotor core 10, that is, the side on which the rotating shaft 50 is provided may be referred to as "radially inside” or “inside.”
  • the outer peripheral side of the rotor core 10 may be referred to as “radially outward” or “outward”.
  • One end surface of the rotor core 10 in the axial direction may be referred to as an “upper surface”, and a surface facing the upper surface may be referred to as a “lower surface”.
  • the side on which the upper surface is disposed may be referred to as “upper”, and the side on which the lower surface is disposed may be referred to as “lower”.
  • the electric motor 300 has the rotor 100 and the stator 200.
  • the electric motor 300 has a plurality of components such as an electric motor case separately, but illustration and detailed description thereof will be omitted for convenience of explanation.
  • the rotor 100 has a substantially cylindrical rotor core 10 and a rotating shaft 50.
  • the rotating shaft 50 is an output shaft that is connected to a driving unit (not shown) provided separately from the electric motor 300 and rotationally drives the driving unit.
  • the rotating shaft 50 is rotatably supported by bearings (not shown) and attached to a motor case (not shown).
  • the rotor core 10 is a substantially cylindrical member formed by laminating a plurality of electromagnetic steel sheets.
  • the rotor core 10 has a through opening 11 extending in the axial direction at the axis.
  • the rotating shaft 50 is inserted into and fixed to the through opening 11 by press fitting or the like.
  • a plurality of magnet insertion holes 12 are formed on the outer peripheral side of the rotor core 10 at predetermined intervals in the circumferential direction.
  • the magnet insertion hole 12 is an opening that passes through the rotor core 10 in the axial direction.
  • the magnet insertion hole 12 has a U-shape that is convex toward the axis when viewed from above.
  • the magnet insertion hole 12 has a convex portion 12b having a convex shape toward the axis when viewed from above, and a straight portion 12a provided to extend straight from both ends of the convex portion 12b to the outer peripheral side of the rotor core 10, respectively. It is composed of As shown in FIG.
  • the straight portion 12a is configured such that the length A in the radial direction is longer than the length B in the circumferential direction.
  • the straight portion 12a may be referred to as a first portion 12a.
  • one of the two straight portions 12a and the convex portion 12b may be referred to as a first portion 12c.
  • a region including a portion of the magnet insertion hole 12 that extends straight from the axial center side of the rotor core 10 to the outer peripheral side may be referred to as a first portion.
  • the first portion 12a or the first portion 12c is configured such that the radial length A is longer than the circumferential length B.
  • the magnet 20 is a permanent magnet embedded in each of the plurality of magnet insertion holes 12 and magnetized in a predetermined direction.
  • a magnet material 30 (see FIGS. 2 and 4) is embedded in each of the plurality of magnet insertion holes 12.
  • the magnet material 30 is magnetized and becomes the magnet 20.
  • the magnetic flux density is set to 1.4 (T) and the coercive force is set to 1700 (kA / m).
  • T 1.4
  • the coercive force is set to 1700 (kA / m).
  • the present invention is not limited to this.
  • the magnetic flux density and the coercive force can be appropriately changed according to the required specifications of the electric motor 300, the number of poles of the rotor 100, and the like.
  • the plurality of magnets 20 are arranged so that the magnets 20 adjacent to each other in the circumferential direction have opposite polarities. For example, in one magnet, if the side surface located on the radially outer side is the N pole, and the side surface located on the radially inner side is the S pole, the magnet adjacent to the one magnet in the circumferential direction is located on the radially outer side.
  • the side surface to be formed is the S pole, and the side surface located radially inward is the N pole. The structure and the like of the magnet 20 will be described later in detail.
  • the stator 200 is provided on the outer peripheral side of the rotor core 10 at a predetermined interval from the rotor core 10.
  • the stator 200 includes a substantially annular yoke portion 210 in a cross-sectional view, and a plurality of tooth portions 220 extending from an inner periphery of the yoke portion 210 and provided at predetermined intervals in a circumferential direction. I have.
  • the yoke 210 and the plurality of teeth 220 form a magnetic core 230 as a magnetic circuit.
  • the magnetic core 230 is formed by laminating a plurality of electromagnetic steel sheets similarly to the rotor iron core 10.
  • a field coil 240 is wound around each of the plurality of teeth 220.
  • An insulator (not shown) is provided between the field coils 240 adjacent in the circumferential direction.
  • Three-phase currents of U, V, and W phases having a phase difference of 120 ° in electrical angle are supplied to a plurality of field coils 240 provided in the stator 200, respectively, and the stator 200 is excited and rotated. A magnetic field is generated. Due to this rotating magnetic field, a rotating torque is generated in the rotor 100, and the rotating shaft 50 supported by a bearing (not shown) rotates around the axis.
  • the broken arrow indicates the d-axis magnetic flux path 60.
  • the portion of the rotor 100 crossed by the dashed arrow is a d-axis magnetic flux path component.
  • the d-axis magnetic flux path forming unit generates a magnet torque of a component of a rotating torque generated by a rotating magnetic field from the stator 200.
  • the d-axis magnetic flux path 60 is configured to pass through two magnets 20 adjacent to each other in the circumferential direction when viewed from above.
  • the solid arrow indicates the q-axis magnetic flux path 61.
  • the portion of the rotor 100 crossed by the solid arrow is a q-axis magnetic flux path component.
  • the q-axis magnetic flux path forming section generates a reluctance torque of a component of a rotating torque generated by a rotating magnetic field from the stator 200.
  • the q-axis magnetic flux passage 61 is configured to pass through a portion of the rotor core 10 located radially outside the magnet 20 in a top view.
  • the d-axis magnetic flux path 60 indicated by a broken-line arrow and the q-axis magnetic flux path 61 indicated by a solid-line arrow schematically illustrate main d-axis magnetic flux paths and q-axis magnetic flux paths.
  • other d-axis and q-axis flux paths that contribute to the generation of magnet or reluctance torque but are not primary may also be considered.
  • other d-axis magnetic flux paths and q-axis magnetic flux paths which are not main only knowledge is described, and details are omitted.
  • FIG. 2A is a perspective view showing the magnet 20 of the electric motor according to Embodiment 1 of the present invention.
  • FIG. 2B is a perspective view showing the split magnet 21 of the electric motor according to Embodiment 1 of the present invention.
  • the magnet 20 has a plurality of divided magnets 21 stacked in the axial direction.
  • the magnet 20 is configured such that its axial length is substantially equal to the axial length of the magnet insertion hole 12.
  • substantially equal means equal including the manufacturing tolerance of the rotor core 10 and the magnet 20.
  • the axial length of the magnet 20 and the axial length of the magnet insertion hole 12 do not have to exactly match.
  • the axial length of the magnet 20 may be shorter than the axial length of the magnet insertion hole 12 as long as a desired magnetic force can be obtained.
  • the outer shape of the magnet 20 is defined along the inner peripheral surface of the magnet insertion hole 12 in a top view. That is, the outer shape of the magnet 20 is U-shaped when viewed from above.
  • the magnet 20 has a convex portion 20b that is convex toward the axis of the rotor core 10 in a state of being embedded in the magnet insertion hole 12, and a straight portion that is provided to extend straight from both ends of the convex portion 20b. 20a.
  • the straight portion 20a may be referred to as a first portion 20a.
  • a portion including one of the two straight portions 20a and the protrusion 20b may be referred to as a first portion 20c.
  • a region including a portion of the magnet 20 that extends straight from the axial center side of the rotor core 10 to the outer peripheral side may be referred to as a first portion.
  • the first portion 20a or the first portion 20c is configured such that the length A in the radial direction is longer than the length B in the circumferential direction.
  • an insulating layer 40 is provided on the upper and lower surfaces of the split magnet 21.
  • the insulating layer 40 is also provided on the side surface of the split magnet 21. That is, the insulating layer 40 is provided on the entire surface of the split magnet 21. Therefore, as shown in FIG. 2A, the insulating layer 40 is provided between the divided magnets 21 adjacent in the axial direction.
  • the insulating layer 40 is formed by applying an insulating resin, for example, an epoxy-based resin to the entire surface of a non-magnetized divided magnet material (hereinafter, simply referred to as a divided magnet material) 31, and then drying and curing the resin. You.
  • the present invention is not particularly limited thereto, and the insulating material may be formed on the surface of the divided magnet material 31 by vapor deposition or the like.
  • the magnet material 30 may be configured by wrapping the divided magnet material 31 with an insulating film and stacking the wrapped divided magnet materials 31 in the axial direction.
  • the magnet material 30 is a sintered body of a magnet powder containing a rare earth such as Nd or Sm, and is a non-magnetized member whose surface is covered with the insulating layer 40.
  • the material of the magnet material 30 is not particularly limited to this, and it is sufficient that the magnet material 30 contains a predetermined amount or more of the unmagnetized magnet material so that a desired magnetic force can be obtained after the magnetization.
  • FIG. 3 is a flowchart showing a procedure for assembling the rotor of the electric motor according to the first embodiment of the present invention.
  • the rotor core 10 is prepared (Step S1).
  • the insulating layer 40 is formed on the surface of the divided magnet material 31, and a predetermined number of divided magnet materials 31 are stacked to prepare the magnet material 30 (Step S2).
  • thermosetting adhesive (not shown) is applied to the inner peripheral surface of each of the plurality of magnet insertion holes 12 to bury the magnet material 30 in the magnet insertion holes 12 (Step S3). Further, the rotor core 10 in which the magnet material 30 is embedded is heated at a predetermined temperature, the adhesive is cured by heat, and the magnet material 30 is positioned and fixed in the magnet insertion hole 12 (step S3).
  • steps S2 and S3 the divided magnet materials 31 each having the insulating layer 40 formed on the surface may be sequentially stacked in the magnet insertion hole 12.
  • Steps S2 and S3 are executed in a state in which a holder (not shown) is arranged so as to be in contact with each of the lower surfaces of the plurality of magnet insertion holes 12 so that the magnet material 30 does not drop.
  • a magnetizing device 400 (see FIG. 4) is arranged on the outer peripheral side of the rotor core 10, and a predetermined magnetic field generated by the magnetizing device 400 is applied to the magnet material 30 to magnetize the magnet material 30. (Step S4). At this time, the magnetizing device 400 generates a magnetic field such that the magnets 20 adjacent to each other in the circumferential direction have opposite polarities.
  • FIG. 4 is a diagram showing the distribution of the lines of magnetic force in the stator in step S4, which is the magnetizing step of the procedure for assembling the rotor of the electric motor according to the first embodiment of the present invention.
  • the magnetizing device 400 generates magnetic lines of force indicated by broken lines by energizing the coil 410.
  • the magnet material 30 can be magnetized into the magnet 20.
  • adjacent coils 410 are provided so as to be reversely wound.
  • the number of turns of the coil 410 is the same.
  • the coils 410 are all connected in series. By doing so, the polarities of the magnets 20 adjacent to each other in the circumferential direction can be made opposite directions, and the magnetic force of each magnet 20 can be made substantially the same.
  • the rotor 100 includes the rotor core 10 having the rotating shaft 50, the plurality of magnet insertion holes 12 provided at predetermined intervals in the circumferential direction, and the magnet insertion hole. And a magnet 20 embedded in each of the twelve.
  • the magnet 20 is composed of divided magnets 21 which are stacked and buried in the axial direction.
  • the divided magnet 21 is formed by magnetizing a divided magnet material 31 from the outside.
  • the magnet insertion hole 12 is provided so as to extend from the outer peripheral side to the axial center side of the rotor core 10 in a top view, and the first portion 12a or the first portion 12c whose radial length is longer than the circumferential length. have.
  • An insulating layer 40 is provided between the divided magnets 21 adjacent in the axial direction.
  • the magnet material 30 can be sufficiently magnetized in one magnetizing step, including the portion located on the side closer to the axis. This will be further described.
  • FIG. 5 is a diagram showing the relationship between the radial distance from the outer periphery of the rotor of the electric motor according to the first embodiment of the present invention and the magnetization rate of the magnet.
  • FIG. 5 shows the result of magnetizing using the magnetizing device 400 shown in FIG. 4 under the conditions of 4000 ⁇ F and 4000 V.
  • the dotted line in the horizontal axis direction shown in FIG. 5 indicates the magnetization ratio ⁇ (%) necessary to satisfy the required performance of the magnet 20.
  • it corresponds to a magnetization rate of about 90%.
  • the magnetization rate ⁇ may be higher or lower than 90% depending on the performance specifications required for the rotor 100 and the like.
  • a rotor core 10 having a diameter of 108 mm and an axial height of 55 mm was used.
  • the magnet 20 used had a length of 25 mm from the tip of the straight portion 20a to the tip of the projection 20b.
  • the length of the magnet 20 in the axial direction is substantially equal to the length of the magnet insertion hole 12 in the axial direction, in other words, the length of the rotor core 10 in the axial direction regardless of the division. did. Therefore, in the case where the magnet 20 is composed of the ten divided magnets 21 stacked, each of the divided magnets 21 has an axial height of 5.46 mm.
  • an epoxy resin having a thickness of 20 ⁇ m was formed on the surface of the divided magnet 21, actually, on the surface of the divided magnet material 31.
  • the magnetizing ratios were compared using a 10-pole rotor 100 in which magnets were buried at 10 places, instead of the 6-pole rotor 100 shown in FIG.
  • the magnetization rate referred to here means that after performing the above-described magnetization, the magnet 20 is pulled out of the rotor 100, and the magnetic flux density of the magnet 20 is measured from the outer peripheral side of the rotor 100 to the axial center side. This is a value calculated by using the magnetic flux density of the magnet at the outer peripheral end as a denominator.
  • the magnetizability is equal to or more than ⁇ from the tip of the straight portion 20a to the region of about 7 mm toward the axial center side. Dropped sharply.
  • the region where the magnetization rate is equal to or more than ⁇ is about 10 mm from the tip of the straight portion 20a toward the axis.
  • the region where the magnetization ratio is equal to or more than ⁇ is about 22 mm from the tip of the straight portion 20a toward the axis. That is, it was possible to magnetize the magnet 20 with a magnetization rate of ⁇ or more up to a portion near the axial center end.
  • FIG. 6 is a schematic diagram showing the state of generation of an eddy current and a demagnetizing field in a magnet according to the first embodiment of the present invention, depending on whether the magnet is divided or not.
  • FIG. 6 shows the side surface of the magnet 20 as a plane.
  • the demagnetizing field depends on the amount of the eddy current and is uniform on the entire side surface of the magnet 20, the external magnetic field at the time of magnetization is further weakened in the convex portion 20b than in the straight portion 20a. For this reason, it is considered that the magnetization rate on the axial center side is greatly reduced.
  • the magnet 20 is configured by a plurality of divided magnets 21 stacked in the axial direction, and between the divided magnets 21 adjacent in the axial direction.
  • An insulating layer 40 is provided.
  • the amount of eddy current generated in each of the divided magnets 21 can be reduced, and the demagnetizing field can be reduced. Therefore, it is possible to suppress the external magnetic field at the time of magnetization from being weakened at the convex portion 20b, and magnetize the magnet material 30 by a smaller number of times, for example, once, to form the magnet 20. Further, simplification of the magnetizing device 400 and reduction of the lead time during assembly can be achieved. Therefore, the manufacturing cost of the rotor 100 can be reduced.
  • a plurality of magnets 20 having a high volume density and improved utilization efficiency can be arranged on the rotor core 10. For this reason, when the rotor 100 of the present embodiment is applied to the electric motor 300, higher rotation torque can be obtained. Further, with the same rotational torque, the volume of the rotor 100 can be reduced.
  • the magnet 20 is magnetized in a state where the plurality of divided magnet materials 31 are stacked in the magnet insertion hole 12 in the axial direction, the magnet 20 is divided into the magnet insertion hole 12.
  • the arrangement of the magnet material 31 can be easily performed. Thereby, the assembly process can be simplified.
  • the rotor 100 of the present embodiment since the plurality of divided magnet materials 31 are arranged in the magnet insertion holes 12, it is possible to prevent a foreign material from being attracted by a magnetic force and to prevent an assembly failure or the like from occurring. Can be. Further, since the divided magnet material 31 is not magnetized, it can be arranged in the magnet insertion hole 12 without being attracted to the rotor core 10 by a magnetic force. Thus, it is possible to prevent the insulating layer 40 provided on the surface of the split magnet 21 from rubbing against the rotor core 10 and coming off. Therefore, the assembly yield of the rotor 100 can be improved.
  • the magnet insertion hole 12 has a convex shape toward the axis of the rotor core 10 in a top view.
  • the outer shape of the magnet 20 is defined along the inner peripheral surface of the magnet insertion hole 12 in a top view.
  • the magnets 20 can be arranged at a high filling rate in each of the plurality of magnet insertion holes 12 whose occupation density in the rotor core 10 is increased. Consequently, the rotational torque of the electric motor 300 can be increased.
  • the outer shape of the magnet 20 into the above shape, the side surfaces of the magnet material 30 and the magnetic force lines generated from the magnetizing device 400 are orthogonal to each other. Therefore, the magnetization of the magnet material 30 becomes easy. As a result, the magnetizing rate of the magnet 20 near the deepest part of the projection 20b, that is, near the axis, is improved, and the utilization efficiency of the magnet 20 can be increased. Further, the rotation torque of the electric motor 300 can be increased.
  • the rotor 100 of the present embodiment has a d-axis magnetic flux path 60 that passes through two magnets 20 that are adjacent to each other in the circumferential direction among the plurality of magnets, and is positioned radially outside the plurality of magnets 20 when viewed from above. And a q-axis magnetic flux passage 61 that passes through the rotor core 10 having a magnetic saliency.
  • both the magnet torque caused by the d-axis magnetic flux passage 60 and the reluctance torque caused by the q-axis magnetic flux passage 61 can be used as the rotation torque of the electric motor 300, and the rotation torque can be increased.
  • the electric motor 300 of the present embodiment includes the rotor 100, and the stator 200 disposed radially outside the rotor 100 with a predetermined interval from the rotor 100.
  • the cost of the rotor 100 can be reduced, and the utilization efficiency of the magnet 20 can be increased. Therefore, the electric motor 300 with high rotational torque can be realized.
  • FIG. 7A is a schematic sectional view showing a rotor 100 according to a modification.
  • FIG. 7B is a schematic sectional view showing a rotor 100 according to another modification.
  • FIG. 7C is a schematic cross-sectional view showing a rotor 100 according to still another modification.
  • the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description will be omitted.
  • the shape of the magnet insertion hole 12 and the magnet 20 may be a V-shape that is convex toward the axis of the rotor core 10 in a top view.
  • the individual shapes of the magnet insertion hole 12 and the magnet 20 are rectangular shapes extending from the outer peripheral side of the rotor core 10 toward the axial center side in a top view. You may make it become a shape.
  • the radial length A of the magnet insertion hole 12 is set to be longer than the circumferential length B.
  • the polarities of the magnets 20 adjacent to each other in the circumferential direction are also opposite.
  • a gap is formed between the magnet insertion hole 12 and the magnet 20.
  • This gap is a clearance naturally generated due to the dimensional tolerance of the magnet 20 and the dimensional tolerance of the electromagnetic steel sheet constituting the rotor core 10.
  • This wide gap is called a so-called flux barrier.
  • the flux barrier has a shape in which the magnet insertion hole 12 is partially larger than the magnet 20, and generally forms a gap having a dimension larger than the clearance caused by the dimensional tolerance described above. is there.
  • FIG. 8 is a perspective view showing a magnet 20 according to the second embodiment of the present invention.
  • FIG. 9 is a perspective view showing another magnet 20 according to the second embodiment of the present invention.
  • the magnet 20 shown in FIG. 8 corresponds to the configuration shown in FIG. 2A.
  • the magnet 20 shown in FIG. 9 corresponds to the configuration shown in FIG. 7C.
  • the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description will be omitted.
  • the configuration shown in the present embodiment is different from the configuration shown in the first embodiment in the following points. 8 and 9, the magnet 20 is divided into a plurality of portions when viewed from above.
  • the first magnet 22 located on the side closer to the axis of the rotor core 10 is divided in the axial direction.
  • the second magnet 23 located on the outer peripheral side of the rotor core 10 is a non-divided magnet that is not divided in the axial direction.
  • An insulating layer 40 is provided at each of the divided portions of the magnet 20.
  • the first magnet 22 located closer to the axis of the rotor core 10 is the magnet insertion hole 12 And a plurality of divided magnets 22a stacked in the axial direction.
  • the insulating layer 40 is provided between the divided magnets 22a adjacent in the axial direction.
  • the second magnet 23 located on the side close to the outer periphery of the rotor core 10 is not divided in the axial direction. The second magnet 23 is provided in radial contact with the first magnet 22 with the insulating layer 40 interposed in the magnet insertion hole 12.
  • the magnet 20, including the first magnet 22 and the second magnet 23, is embedded in the first portion 12a or the first portion 12c of the magnet insertion hole 12.
  • the magnet 20 is formed by magnetizing a plurality of divided magnet materials 31 from the outside.
  • the first magnet 22 near the axis can be easily magnetized and the demagnetization of the second magnet 23 near the outer periphery side, as in the first embodiment. Can be suppressed. This will be further described.
  • the magnet 20 arranged in the magnet insertion hole 12 is divided in the axial direction, and the insulating layer 40 is provided between the divided magnets 21 adjacent in the axial direction.
  • the eddy current generated in each of the magnets 21 can be reduced, and the demagnetizing field generated in the direction opposite to the external magnetic field can be reduced. This is advantageous when the magnet material 30 is magnetized, but may cause another problem described below.
  • the magnet 20 when the magnet 20 is composed of a plurality of divided magnets 21 and the insulating layer 40 is provided between the divided magnets 21 adjacent in the axial direction, the eddy current generated in each of the divided magnets 21 is reduced. As a result, the demagnetizing field becomes small. For this reason, depending on the strength of the magnetic field generated in the stator 200 or the set value of the coercive force of the magnet 20, demagnetization is more likely to occur on the side closer to the outer periphery of the rotor core than the undivided magnet. As a result, the performance of the electric motor 300, for example, the rotational torque may be reduced.
  • the second magnet 23 located on the outer peripheral side of the rotor core 10 is a non-split magnet in the axial direction, so that the eddy current generated in the second magnet 23 and the The demagnetizing field can be strengthened. Thereby, the second magnet 23 can be prevented from being demagnetized by the magnetic field from the stator 200.
  • the first magnet 22 located on the axis side of the rotor core 10 is the same as in the first embodiment, and the insulating layer 40 is provided between the second magnet 23 and the first magnet 22 so that the first magnet 22 And the utilization efficiency of the magnet 20 can be increased. Thereby, the electric motor 300 with high rotation torque can be realized.
  • the volume of the rotor core 10 located radially outside the second magnet 23 is small, an external magnetic field sufficiently enters the magnet material 30 during magnetization. For this reason, even if the eddy current generated in the second magnet 23 increases, the second magnet 23 can be sufficiently magnetized by one magnetization.
  • the outer shapes of the first magnet 22 and the second magnet 23 embedded in the first portion 12a or the first portion 12c of the magnet insertion hole 12 are formed on the inner peripheral surface of the first portion 12a or the first portion 12c in a top view. It is specified to follow.
  • the magnets 20 can be arranged at a high filling rate, as in the first embodiment. Therefore, the rotation torque of electric motor 300 can be increased.
  • the ratio of the insulating layer 40 in the magnet 20 is reduced. For this reason, the ratio of the sintered body that generates a magnetic force increases. Therefore, the magnetic force of the magnet 20 can be improved.
  • the ratio of the radial length L1 of the first magnet 22 to the radial length L2 of the second magnet 23 is set in accordance with the ease of magnetization of the magnet 20, the degree of demagnetization, and the like.
  • the second magnet 23 does not have to be non-divided in the axial direction, and may be divided. However, in this case, the surface area of the side surface of the second magnet 23 is set to be larger than the surface area of the side surface of one divided magnet 22a in the first magnet 22. By doing so, the eddy current and the demagnetizing field generated in the second magnet 23 can be increased, and the demagnetization of the second magnet 23 can be suppressed.
  • the second magnet 23 is not divided in the axial direction, in other words, when the axial length of the second magnet 23 is made substantially equal to the axial length of the magnet insertion hole 12, demagnetization is achieved. Needless to say, the degree of suppression is improved.
  • the rotor 100 includes the rotor core 10 having the plurality of magnet insertion holes 12 provided at predetermined intervals in the circumferential direction along the outer circumference, And a magnet 20 buried in each of the magnet insertion holes 12.
  • Each of the plurality of magnet insertion holes 12 has a first portion 12c provided to extend from the outer peripheral side of the rotor core 10 to the axial center side of the rotor core 10 in a top view.
  • the magnet 20 includes a first magnet 22 buried in the first portion 12 c and located on a side closer to the axis of the rotor core 10, and the first magnet 22 includes a plurality of magnets stacked in the axial direction in which the rotation shaft 50 extends. Of the divided magnet 21.
  • the insulating layer 40 is provided between the plurality of divided magnets 21 adjacent in the axial direction.
  • the magnet 20 includes a second magnet 23 buried in the first portion 12 c and located on a side near the outer periphery of the rotor core 10, and a surface area of a side surface of the second magnet 23 is one divided magnet of the first magnet 22. 21 is larger than the surface area of the side surface.
  • the second magnet 23 is provided in contact with the first magnet 22 in the radial direction which is the radial direction 10 of the rotor core with the insulating layer 40 interposed in the plurality of magnet insertion holes 12.
  • the utilization efficiency of the first magnet 22 can be increased. Further, by making the surface area of the second magnet 23 larger than the surface area of one divided magnet 21 in the first magnet 22, the degree of demagnetization of the second magnet 23 by the magnetic field from the stator 200 is reduced. can do. Further, the ratio of the insulating layer 40 in the second magnet 23 can be reduced. For this reason, the magnetic force of the whole magnet can be improved.
  • the rotor 100 has a six-pole configuration in which six magnets 20 are arranged in the rotor core 10.
  • a 10-pole configuration may be used.
  • a four-pole configuration or a twelve-pole configuration may be used.
  • a configuration relating to the number of poles is not particularly limited. In that case, the number of the teeth 220 of the stator 200 and the number of the field coils 240 are appropriately changed.
  • the divided magnet material 31 is disposed in the magnet insertion hole 12 and then magnetized from the outside to obtain the divided magnet 21.
  • the rotor of the present invention can improve the rotational efficiency by increasing the utilization efficiency of the magnet, and is useful when applied to an electric motor.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Permanent Field Magnets Of Synchronous Machinery (AREA)

Abstract

This rotor comprises: a rotary shaft; a rotor core having a plurality of magnet insertion holes provided spaced apart at prescribed intervals in a circumferential direction along an outer circumference; and a plurality of magnets embedded respectively into the plurality of magnet insertion holes. Each of the plurality of magnets is composed of a plurality of divided magnets embedded so as to be stacked on one another in an axial direction along which the rotary shaft extends. Each of the plurality of magnet insertion holes is provided so as to extend from an outer circumferential side of the rotor core toward an axial center thereof in a top plan view, and each has a first portion of which a dimension in a radial direction corresponding to the radial direction of the rotor core is longer than a dimension in the circumferential direction. Insulating layers are provided between the divided magnets disposed adjacent to each other in the axial direction.

Description

回転子及びそれを用いた電動機Rotor and electric motor using the same
　本発明は、回転子及びそれを用いた電動機に関する。本発明は特に、内部に永久磁石が配置された回転子に関する。 The present invention relates to a rotor and an electric motor using the same. The invention particularly relates to a rotor having a permanent magnet disposed therein.
　従来、回転子鉄心内に永久磁石（以下、単に磁石という）を埋め込んだ構造のＩＰＭ（Ｉｎｔｅｒｎａｌ　Ｐｅｒｍａｎｅｎｔ　Ｍａｇｎｅｔ）モータが知られている。ＩＰＭモータは、回転子鉄心の表面に磁石を配置したＳＰＭ（Ｓｕｒｆａｃｅ　Ｐｅｒｍａｎｅｎｔ　Ｍａｇｎｅｔ）モータに比べ、リラクタンストルクが利用できるため、高い回転トルクが得られる。また、ＩＰＭモータでは、同じ体積の回転子鉄心に対して、高体積密度で磁石を配置するために、回転子鉄心に上面視でＶ字形状またはＵ字形状の磁石挿入孔を設け、磁石挿入孔の内周面に外形が沿うように形成された磁石を埋設する構成が知られている。 Conventionally, there has been known an IPM (Internal Permanent Magnet) motor having a structure in which a permanent magnet (hereinafter, simply referred to as a magnet) is embedded in a rotor core. An IPM motor can use higher reluctance torque than a SPM (Surface Permanent Magnet) motor in which a magnet is arranged on the surface of a rotor core, so that a higher rotation torque can be obtained. In the IPM motor, a magnet insertion hole having a V-shape or a U-shape as viewed from above is provided in the rotor core in order to dispose a magnet at a high volume density with respect to the rotor core having the same volume. There is known a configuration in which a magnet formed so as to have an outer shape along the inner peripheral surface of a hole is embedded.
　この構成において、未着磁状態である磁石素材（以下、単に磁石素材という）を磁石挿入孔に埋設した後、外部から磁界を印加して磁石素材を磁石に変化させる、一般に着磁と呼ばれる方法が広く採用されている（例えば、特許文献１を参照）。 In this configuration, after a magnet material in a non-magnetized state (hereinafter simply referred to as a magnet material) is embedded in a magnet insertion hole, a magnetic field is applied from the outside to change the magnet material into a magnet. Is widely adopted (for example, see Patent Document 1).
　特許文献２には、磁界を印加しながら磁石素材を磁石挿入孔内に注入成形して磁石とする一方、着磁済の磁石を磁石挿入孔内の回転子鉄心の軸心に近い側に配設することで、磁石全体の磁力のばらつきを防止する構成が開示されている。 Patent Document 2 discloses that a magnet material is injected into a magnet insertion hole to form a magnet while applying a magnetic field, while a magnetized magnet is disposed in the magnet insertion hole on the side near the axis of the rotor core. A configuration that prevents variations in the magnetic force of the entire magnet by providing the magnet is disclosed.
　一般に、外部から印加された磁界は回転子鉄心内を減衰しながら進行する。このため、上述の着磁を行うと、回転子鉄心の軸心に近い側で磁石が十分に着磁できず、磁石の利用効率が低下することがある。これを防止するため、特許文献１に開示される構成では、複数の着磁装置を用いて複数回の部分着磁を行っている。しかし、この方法では、製造時のリードタイムまたは設備コストが増加してしまう。 Generally, an externally applied magnetic field travels while attenuating inside the rotor core. Therefore, when the above-described magnetization is performed, the magnet cannot be sufficiently magnetized on the side near the axis of the rotor core, and the utilization efficiency of the magnet may be reduced. In order to prevent this, in the configuration disclosed in Patent Document 1, a plurality of partial magnetizations are performed using a plurality of magnetization devices. However, this method increases the lead time or equipment cost during manufacturing.
　特許文献２に開示される方法では、着磁済の磁石と回転子鉄心との間に強い吸引力が働く。このため、磁石のハンドリングが難しく、所定の位置に磁石を配置できないおそれがあった。また、回転子鉄心と磁石とが擦れて、磁石の表面に設けられた被膜が剥がれるおそれがあった。 で は In the method disclosed in Patent Document 2, a strong attractive force acts between the magnetized magnet and the rotor core. For this reason, handling of the magnet is difficult, and there is a possibility that the magnet cannot be arranged at a predetermined position. In addition, the rotor core and the magnet may be rubbed, and the coating provided on the surface of the magnet may be peeled off.
日本国特許第６０６２９００号公報Japanese Patent No. 6062900 特開２０１６－０８２７９８号公報Japanese Patent Application Laid-Open No. 2016-082798
　本発明はかかる点に鑑みてなされたものである。本発明の目的は、磁石の利用効率を高めるとともに、回転子鉄心内に磁石を簡便に配置できる回転子及びそれを用いた電動機を提供することにある。 The present invention has been made in view of such a point. SUMMARY OF THE INVENTION An object of the present invention is to provide a rotor and a motor using the same, which can improve the utilization efficiency of the magnet and can easily arrange the magnet in the rotor core.
　上記目的を達成するため、本発明に係る回転子は、回転軸と、外周に沿った周方向に所定の間隔をあけて設けられた複数の磁石挿入孔を有する回転子鉄心と、複数の磁石挿入孔のそれぞれに埋設された複数の磁石と、を備える。複数の磁石の各々は、回転軸の延びる軸方向に積み重ねられて埋設された複数の分割磁石からなる。複数の磁石挿入孔の各々は、上面視で回転子鉄心の外周側から回転子鉄心の軸心側にかけて延びるように設けられ、かつ回転子鉄心の半径方向である径方向の長さが周方向の長さよりも長い第１部分を有する。軸方向に隣り合う複数の分割磁石の間に絶縁層が設けられている。 In order to achieve the above object, a rotor according to the present invention includes a rotating shaft, a rotor core having a plurality of magnet insertion holes provided at predetermined intervals in a circumferential direction along an outer periphery, and a plurality of magnets. A plurality of magnets embedded in each of the insertion holes. Each of the plurality of magnets is composed of a plurality of divided magnets that are stacked and embedded in the axial direction in which the rotation axis extends. Each of the plurality of magnet insertion holes is provided so as to extend from the outer peripheral side of the rotor core to the axis side of the rotor core in a top view, and the radial length of the rotor core in the radial direction is the circumferential direction. Has a first portion that is longer than the length. An insulating layer is provided between the plurality of divided magnets adjacent in the axial direction.
　この構成によれば、着磁時に分割磁石の各々で発生する渦電流を低減でき回転子鉄心の軸心に近い側の磁石の着磁率が低下するのを抑制できる。これにより、回転子における磁石の利用効率を高めることができる。また、回転子鉄心内に磁石を簡便に配置できる。 According to this configuration, the eddy current generated in each of the divided magnets at the time of magnetization can be reduced, and a decrease in the magnetization rate of the magnet near the axis of the rotor core can be suppressed. Thereby, the utilization efficiency of the magnet in the rotor can be increased. Further, the magnet can be easily arranged in the rotor core.
　また、複数の磁石のうちの一つの磁石の外形は、上面視で複数の磁石挿入孔のうちの一つの磁石挿入孔の内周面に沿うように規定されていることが好ましい。 It is preferable that the outer shape of one of the plurality of magnets is defined along the inner peripheral surface of one of the plurality of magnet insertion holes when viewed from above.
　また、複数の磁石挿入孔は、上面視で回転子鉄心の軸心に向かって凸形状であってもよい。 The plurality of magnet insertion holes may be convex toward the axis of the rotor core in a top view.
　また、磁石挿入孔は、上面視で回転子鉄心の外周側から回転子鉄心の軸心側に向かって延びる長方形状であってもよい。 The magnet insertion hole may have a rectangular shape extending from the outer peripheral side of the rotor core toward the axis of the rotor core in a top view.
　また、回転子は、上面視で、複数の磁石のうち、周方向に隣り合う２つの磁石をそれぞれ通るｄ軸磁束通路と、複数の磁石の径方向外側に位置する回転子鉄心を通るｑ軸磁束通路とが形成され、磁気的突極性を有してもよい。 Further, the rotor has a d-axis magnetic flux passage passing through two magnets adjacent in the circumferential direction among a plurality of magnets, and a q-axis passing through a rotor core located radially outside of the plurality of magnets when viewed from above. A magnetic flux path may be formed and have magnetic saliency.
　また、本発明に係る別の回転子は、回転軸と、外周に沿った周方向に所定の間隔をあけて設けられた複数の磁石挿入孔を有する回転子鉄心と、複数の磁石挿入孔のそれぞれに埋設された複数の磁石と、を備える。複数の磁石挿入孔の各々は、上面視で回転子鉄心の外周側から回転子鉄心の軸心側にかけて延びるように設けられた第１部分を有する。複数の磁石の各々は、第１部分に埋設され、回転子鉄心の軸心に近い側に位置する第１磁石を含み、第１磁石は、回転軸の延びる軸方向に積み重ねられた複数の分割磁石で構成される。軸方向に隣り合う複数の分割磁石の間に絶縁層が設けられている。複数の磁石の各々は、第１部分に埋設され、回転子鉄心の外周に近い側に位置する第２磁石を含み、第２磁石の側面の表面積は、第１磁石における１つの分割磁石の側面の表面積よりも大きい。第２磁石は、複数の磁石挿入孔内で絶縁層を挟んで第１磁石と回転子鉄心の半径方向である径方向で接して設けられている。 Further, another rotor according to the present invention includes a rotating shaft, a rotor core having a plurality of magnet insertion holes provided at predetermined intervals in a circumferential direction along the outer periphery, and a plurality of magnet insertion holes. And a plurality of magnets embedded in each of them. Each of the plurality of magnet insertion holes has a first portion provided to extend from the outer peripheral side of the rotor core to the axial center side of the rotor core in a top view. Each of the plurality of magnets includes a first magnet embedded in the first portion and located on a side closer to the axis of the rotor core, the first magnet being a plurality of divided segments stacked in the axial direction of the rotation axis. It is composed of magnets. An insulating layer is provided between the plurality of divided magnets adjacent in the axial direction. Each of the plurality of magnets includes a second magnet embedded in the first portion and located on a side closer to the outer periphery of the rotor core, and a surface area of a side surface of the second magnet is a side surface of one split magnet in the first magnet. Greater than the surface area. The second magnet is provided in contact with the first magnet in a radial direction that is a radial direction of the rotor core with the insulating layer interposed in the plurality of magnet insertion holes.
　この構成によれば、第１磁石において、軸方向に隣り合う分割磁石の間に絶縁層を設けることで、分割磁石のそれぞれで発生する渦電流を低減して、着磁率が低下するのを抑制できる。したがって、第１磁石の利用効率を高められる。また、第２磁石の表面積が第１磁石における１つの分割磁石の表面積よりも大きくなるようにすることで、固定子からの磁界によって第２磁石が減磁される度合いを小さくすることができる。また、第２磁石における絶縁層の比率を低減できる。このため、磁石全体の磁力を向上できる。 According to this configuration, in the first magnet, by providing the insulating layer between the divided magnets adjacent in the axial direction, the eddy current generated in each of the divided magnets is reduced, and the decrease in the magnetization rate is suppressed. it can. Therefore, the utilization efficiency of the first magnet can be increased. Further, by making the surface area of the second magnet larger than the surface area of one divided magnet in the first magnet, the degree of demagnetization of the second magnet by the magnetic field from the stator can be reduced. Further, the ratio of the insulating layer in the second magnet can be reduced. For this reason, the magnetic force of the whole magnet can be improved.
　また、複数の磁石の各々の第１部分に埋設された部分の外形は、上面視で第１部分の内周面に沿うように規定されていることが好ましい。 It is preferable that the outer shape of the portion buried in the first portion of each of the plurality of magnets is defined along the inner peripheral surface of the first portion in a top view.
　また、第２磁石の軸方向の長さは複数の磁石挿入孔の軸方向の長さに実質的に等しいことが好ましい。 It is preferable that the axial length of the second magnet is substantially equal to the axial length of the plurality of magnet insertion holes.
　本発明に係る電動機は、上記のいずれかの回転子と、回転子と所定の間隔をあけて配設された固定子と、を少なくとも備える。 The electric motor according to the present invention includes at least one of the above-described rotors and a stator disposed at a predetermined distance from the rotor.
　この構成によれば、磁石の利用効率を高めることで、高い回転トルクを得ることができる。 According to this configuration, a high rotational torque can be obtained by increasing the utilization efficiency of the magnet.
　本発明の回転子によれば、磁石の利用効率を高められるとともに、回転子鉄心内に磁石を簡便に配置できる。本発明の電動機によれば、高い回転トルクが得られる。 According to the rotor of the present invention, the utilization efficiency of the magnet can be improved, and the magnet can be easily arranged in the rotor core. According to the electric motor of the present invention, a high rotational torque can be obtained.
本発明の実施形態１に係る電動機の要部を示す断面模式図である。FIG. 2 is a schematic cross-sectional view illustrating a main part of the electric motor according to the first embodiment of the present invention. 本発明の実施形態１に係る電動機の磁石を示す斜視図である。It is a perspective view showing the magnet of the electric motor concerning Embodiment 1 of the present invention. 本発明の実施形態１に係る電動機の分割磁石を示す斜視図である。FIG. 2 is a perspective view illustrating a split magnet of the electric motor according to the first embodiment of the present invention. 本発明の実施形態１に係る電動機の回転子の組立手順を示すフローチャートである。4 is a flowchart illustrating an assembling procedure of the rotor of the electric motor according to the first embodiment of the present invention. 本発明の実施形態１に係る電動機の回転子の組立手順の着磁工程における固定子内での磁力線の分布を示す図である。It is a figure which shows the distribution of the magnetic force line in a stator in the magnetizing process of the assembly procedure of the rotor of the electric motor which concerns on Embodiment 1 of this invention. 本発明の実施形態１に係る電動機の回転子外周からの径方向の距離と磁石の着磁率との関係を示す図である。FIG. 4 is a diagram illustrating a relationship between a radial distance from an outer periphery of a rotor of the electric motor according to the first embodiment of the present invention and a magnetization rate of a magnet. 本発明の実施形態１に係る電動機の磁石の分割の有無による磁石での渦電流及び反磁界の発生状態を示す模式図である。It is a schematic diagram which shows the generation state of the eddy current and the demagnetizing field in the magnet by the presence or absence of the division | segmentation of the magnet of the electric motor which concerns on Embodiment 1 of this invention. 変形例に係る回転子を示す断面模式図である。It is a cross section showing a rotor concerning a modification. 別の変形例に係る回転子を示す断面模式図である。It is a cross section showing a rotor concerning another modification. さらなる別の変形例に係る回転子を示す断面模式図である。FIG. 13 is a schematic cross-sectional view showing a rotor according to still another modification. 本発明の実施形態２に係る磁石を示す斜視図である。It is a perspective view showing a magnet concerning Embodiment 2 of the present invention. 本発明の実施形態２に係る別の磁石を示す斜視図である。It is a perspective view showing another magnet concerning Embodiment 2 of the present invention.
　以下、本発明の実施形態を図面に基づいて詳細に説明する。以下の好ましい実施形態の説明は、本質的に例示に過ぎず、本発明、その適用物或いはその用途を制限することを意図するものでは全くない。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The description of the preferred embodiments below is merely exemplary in nature and is in no way intended to limit the invention, its applications, or its uses.
　（実施形態１）
　［電動機の要部の構成］
　図１は、本発明の実施形態１に係る電動機の要部を示す断面模式図である。なお、以降の説明において、回転子鉄心１０に配設された回転軸５０の延びる方向を「軸方向」と、回転子鉄心１０の半径方向を「径方向」と、回転子鉄心１０の外周に沿った方向を「周方向」とそれぞれ呼ぶことがある。径方向において、回転子鉄心１０の軸心、つまり、回転軸５０が配設された側を「径方向内側」または「内側」と呼ぶことがある。回転子鉄心１０の外周側を「径方向外側」または「外側」と呼ぶことがある。回転子鉄心１０の軸方向の一端面を「上面」と呼び、上面と対向する面を「下面」と呼ぶことがある。上面が配置された側を「上側」と、下面が配置された側を「下側」とそれぞれ呼ぶことがある。 (Embodiment 1)
[Configuration of main part of motor]
FIG. 1 is a schematic cross-sectional view illustrating a main part of an electric motor according to Embodiment 1 of the present invention. In the following description, the direction in which the rotating shaft 50 provided on the rotor core 10 extends is referred to as “axial direction”, the radial direction of the rotor core 10 is referred to as “radial direction”, and the outer periphery of the rotor core 10 is referred to as “radial direction”. The directions along are sometimes referred to as “circumferential directions”. In the radial direction, the axis of the rotor core 10, that is, the side on which the rotating shaft 50 is provided may be referred to as "radially inside" or "inside." The outer peripheral side of the rotor core 10 may be referred to as “radially outward” or “outward”. One end surface of the rotor core 10 in the axial direction may be referred to as an “upper surface”, and a surface facing the upper surface may be referred to as a “lower surface”. The side on which the upper surface is disposed may be referred to as “upper”, and the side on which the lower surface is disposed may be referred to as “lower”.
　電動機３００は、回転子１００と固定子２００とを有している。電動機３００は、電動機ケース等の複数の構成部品を別途有しているが、説明の便宜上、これらについては図示及び詳細な説明を省略する。 The electric motor 300 has the rotor 100 and the stator 200. The electric motor 300 has a plurality of components such as an electric motor case separately, but illustration and detailed description thereof will be omitted for convenience of explanation.
　回転子１００は、実質的な円筒形状の回転子鉄心１０と回転軸５０とを有している。回転軸５０は、電動機３００と別に設けられた駆動部（図示せず）に連結されて、駆動部を回転駆動する出力軸である。回転軸５０は、軸受（図示せず）に回転自在に支持されて電動機ケース（図示せず）に取付けられている。 The rotor 100 has a substantially cylindrical rotor core 10 and a rotating shaft 50. The rotating shaft 50 is an output shaft that is connected to a driving unit (not shown) provided separately from the electric motor 300 and rotationally drives the driving unit. The rotating shaft 50 is rotatably supported by bearings (not shown) and attached to a motor case (not shown).
　回転子鉄心１０は、複数の電磁鋼板が積層されてなる実質的な円筒状の部材である。回転子鉄心１０は、軸方向に延びる貫通開口１１を軸心に有している。貫通開口１１には、回転軸５０が圧入等により挿通、固定されている。 The rotor core 10 is a substantially cylindrical member formed by laminating a plurality of electromagnetic steel sheets. The rotor core 10 has a through opening 11 extending in the axial direction at the axis. The rotating shaft 50 is inserted into and fixed to the through opening 11 by press fitting or the like.
　回転子鉄心１０の外周側には、周方向に所定の間隔をあけて複数の磁石挿入孔１２が形成されている。磁石挿入孔１２は、回転子鉄心１０を軸方向に貫通する開口である。磁石挿入孔１２は、上面視で軸心に向かって凸であるＵ字形状をなしている。磁石挿入孔１２は、上面視で、軸心に向かって凸形状となる凸部１２ｂと、凸部１２ｂの両端からそれぞれ回転子鉄心１０の外周側にかけてストレートに延びるように設けられたストレート部１２ａとで構成されている。図１に示すように、ストレート部１２ａは、径方向の長さＡが周方向の長さＢよりも長くなるように構成されている。なお、以降の説明において、ストレート部１２ａを第１部分１２ａと呼ぶことがある。また、２つあるストレート部１２ａの一方と凸部１２ｂとを含めて、第１部分１２ｃと呼ぶことがある。言いかえると、磁石挿入孔１２のうち、回転子鉄心１０の軸心側から外周側にかけてストレートに延びる部分を含む領域を第１部分と呼ぶことがある。ただし、いずれの場合も、第１部分１２ａまたは第１部分１２ｃは、径方向の長さＡが周方向の長さＢよりも長くなるように構成されている。 複数 A plurality of magnet insertion holes 12 are formed on the outer peripheral side of the rotor core 10 at predetermined intervals in the circumferential direction. The magnet insertion hole 12 is an opening that passes through the rotor core 10 in the axial direction. The magnet insertion hole 12 has a U-shape that is convex toward the axis when viewed from above. The magnet insertion hole 12 has a convex portion 12b having a convex shape toward the axis when viewed from above, and a straight portion 12a provided to extend straight from both ends of the convex portion 12b to the outer peripheral side of the rotor core 10, respectively. It is composed of As shown in FIG. 1, the straight portion 12a is configured such that the length A in the radial direction is longer than the length B in the circumferential direction. In the following description, the straight portion 12a may be referred to as a first portion 12a. Also, one of the two straight portions 12a and the convex portion 12b may be referred to as a first portion 12c. In other words, a region including a portion of the magnet insertion hole 12 that extends straight from the axial center side of the rotor core 10 to the outer peripheral side may be referred to as a first portion. However, in any case, the first portion 12a or the first portion 12c is configured such that the radial length A is longer than the circumferential length B.
　磁石２０は、複数の磁石挿入孔１２のそれぞれに埋設されており、所定の方向に磁化された永久磁石である。なお、後述するように、回転子１００の組立時には、複数の磁石挿入孔１２のそれぞれに磁石素材３０（図２、図４を参照）が埋設される。外部から所定の磁界が印加されることで、磁石素材３０が着磁され磁石２０となる。本実施形態における磁石２０の各々において、磁束密度が１．４（Ｔ）、保磁力が１７００（ｋＡ／ｍ）となるようにしているが、特にこれに限定されない。磁束密度及び保磁力は、電動機３００の要求仕様または回転子１００の極数等に応じて適宜変更されうる。 The magnet 20 is a permanent magnet embedded in each of the plurality of magnet insertion holes 12 and magnetized in a predetermined direction. As will be described later, when assembling the rotor 100, a magnet material 30 (see FIGS. 2 and 4) is embedded in each of the plurality of magnet insertion holes 12. When a predetermined magnetic field is applied from the outside, the magnet material 30 is magnetized and becomes the magnet 20. In each of the magnets 20 in the present embodiment, the magnetic flux density is set to 1.4 (T) and the coercive force is set to 1700 (kA / m). However, the present invention is not limited to this. The magnetic flux density and the coercive force can be appropriately changed according to the required specifications of the electric motor 300, the number of poles of the rotor 100, and the like.
　なお、複数ある磁石２０は、周方向において互いに隣り合う磁石２０の極性が反対向きとなるように配置されている。例えば、一の磁石において、径方向外側に位置する側面がＮ極、径方向内側に位置する側面がＳ極であるとすると、周方向において一の磁石に隣り合う磁石では、径方向外側に位置する側面がＳ極、径方向内側に位置する側面がＮ極である。磁石２０の構造等については後で詳述する。 The plurality of magnets 20 are arranged so that the magnets 20 adjacent to each other in the circumferential direction have opposite polarities. For example, in one magnet, if the side surface located on the radially outer side is the N pole, and the side surface located on the radially inner side is the S pole, the magnet adjacent to the one magnet in the circumferential direction is located on the radially outer side. The side surface to be formed is the S pole, and the side surface located radially inward is the N pole. The structure and the like of the magnet 20 will be described later in detail.
　固定子２００は、回転子鉄心１０の外周側に回転子鉄心１０と所定の間隔をあけて設けられている。固定子２００は、断面視で実質的に環状のヨーク部２１０と、ヨーク部２１０の内周から延び、かつ周方向に所定の間隔をあけて設けられた複数の歯部２２０とを有している。ヨーク部２１０と複数の歯部２２０とで磁気回路である磁心２３０を構成している。磁心２３０は、回転子鉄心１０と同様に複数の電磁鋼板が積層されてなる。複数ある歯部２２０のそれぞれには、界磁コイル２４０が巻装されている。周方向に隣り合う界磁コイル２４０の間には、図示しないインシュレータが設けられている。 The stator 200 is provided on the outer peripheral side of the rotor core 10 at a predetermined interval from the rotor core 10. The stator 200 includes a substantially annular yoke portion 210 in a cross-sectional view, and a plurality of tooth portions 220 extending from an inner periphery of the yoke portion 210 and provided at predetermined intervals in a circumferential direction. I have. The yoke 210 and the plurality of teeth 220 form a magnetic core 230 as a magnetic circuit. The magnetic core 230 is formed by laminating a plurality of electromagnetic steel sheets similarly to the rotor iron core 10. A field coil 240 is wound around each of the plurality of teeth 220. An insulator (not shown) is provided between the field coils 240 adjacent in the circumferential direction.
　互いに電気角で１２０°の位相差を有するＵ，Ｖ，Ｗ相の３相の電流がそれぞれ固定子２００に設けられた複数の界磁コイル２４０に供給されて、固定子２００が励磁され、回転磁界が発生する。この回転磁界により、回転子１００に回転トルクが発生し、図示しない軸受に支持された回転軸５０が軸線周りに回転する。 Three-phase currents of U, V, and W phases having a phase difference of 120 ° in electrical angle are supplied to a plurality of field coils 240 provided in the stator 200, respectively, and the stator 200 is excited and rotated. A magnetic field is generated. Due to this rotating magnetic field, a rotating torque is generated in the rotor 100, and the rotating shaft 50 supported by a bearing (not shown) rotates around the axis.
　破線の矢印はｄ軸磁束通路６０を示す。破線の矢印の横切る回転子１００の部位はｄ軸磁束通路構成部である。ｄ軸磁束通路構成部は、固定子２００からの回転磁界によって発生する回転トルクの成分のうちのマグネットトルクを発生させる。ｄ軸磁束通路６０は、上面視で、周方向に隣りあう２つの磁石２０をそれぞれ通るように構成されている。実線の矢印はｑ軸磁束通路６１を示す。実線の矢印の横切る回転子１００の部位はｑ軸磁束通路構成部である。ｑ軸磁束通路構成部は、固定子２００からの回転磁界によって発生する回転トルクの成分のうちのリラクタンストルクを発生させる。ｑ軸磁束通路６１は、上面視で、回転子鉄心１０の磁石２０より径方向外側に位置する部分を通るように構成されている。 The broken arrow indicates the d-axis magnetic flux path 60. The portion of the rotor 100 crossed by the dashed arrow is a d-axis magnetic flux path component. The d-axis magnetic flux path forming unit generates a magnet torque of a component of a rotating torque generated by a rotating magnetic field from the stator 200. The d-axis magnetic flux path 60 is configured to pass through two magnets 20 adjacent to each other in the circumferential direction when viewed from above. The solid arrow indicates the q-axis magnetic flux path 61. The portion of the rotor 100 crossed by the solid arrow is a q-axis magnetic flux path component. The q-axis magnetic flux path forming section generates a reluctance torque of a component of a rotating torque generated by a rotating magnetic field from the stator 200. The q-axis magnetic flux passage 61 is configured to pass through a portion of the rotor core 10 located radially outside the magnet 20 in a top view.
　なお、破線の矢印で示すｄ軸磁束通路６０及び実線の矢印で示すｑ軸磁束通路６１は、主要なｄ軸磁束通路及びｑ軸磁束通路を模式的に例示する。主要なｄ軸磁束通路及びｑ軸磁束通路の他に、マグネットトルクまたはリラクタンストルクの発生に寄与するが、主要ではない別のｄ軸磁束通路及びｑ軸磁束通路も考察し得る。主要ではない別のｄ軸磁束通路及びｑ軸磁束通路については、知見を記すに留め、詳細については記載を省略する。 The d-axis magnetic flux path 60 indicated by a broken-line arrow and the q-axis magnetic flux path 61 indicated by a solid-line arrow schematically illustrate main d-axis magnetic flux paths and q-axis magnetic flux paths. In addition to the primary d-axis and q-axis flux paths, other d-axis and q-axis flux paths that contribute to the generation of magnet or reluctance torque but are not primary may also be considered. Regarding other d-axis magnetic flux paths and q-axis magnetic flux paths which are not main, only knowledge is described, and details are omitted.
　［磁石の構成］
　図２Ａは、本発明の実施形態１に係る電動機の磁石２０を示す斜視図である。図２Ｂは、本発明の実施形態１に係る電動機の分割磁石２１を示す斜視図である。 [Structure of magnet]
FIG. 2A is a perspective view showing the magnet 20 of the electric motor according to Embodiment 1 of the present invention. FIG. 2B is a perspective view showing the split magnet 21 of the electric motor according to Embodiment 1 of the present invention.
　図２Ａに示すように、磁石２０は、複数の分割磁石２１が軸方向に積み重ねられている。磁石２０は、軸方向の長さが磁石挿入孔１２の軸方向の長さに実質的に等しくなるように構成されている。なお、本願明細書において、「実質的に等しい」とは、回転子鉄心１０及び磁石２０の製造公差を含んで等しいという意味である。磁石２０の軸方向の長さと磁石挿入孔１２の軸方向の長さとが厳密に一致していなくてもよい。所望の磁力が得られる範囲で、磁石２０の軸方向の長さは磁石挿入孔１２の軸方向の長さより短くてもよい。 磁石 As shown in FIG. 2A, the magnet 20 has a plurality of divided magnets 21 stacked in the axial direction. The magnet 20 is configured such that its axial length is substantially equal to the axial length of the magnet insertion hole 12. In the present specification, “substantially equal” means equal including the manufacturing tolerance of the rotor core 10 and the magnet 20. The axial length of the magnet 20 and the axial length of the magnet insertion hole 12 do not have to exactly match. The axial length of the magnet 20 may be shorter than the axial length of the magnet insertion hole 12 as long as a desired magnetic force can be obtained.
　磁石２０の外形は、上面視で、磁石挿入孔１２の内周面に沿うように規定されている。つまり、磁石２０の外形は、上面視でＵ字形状である。磁石２０は、磁石挿入孔１２に埋設された状態で回転子鉄心１０の軸心に向かって凸形状である凸部２０ｂと、凸部２０ｂの両端からそれぞれストレートに延びるように設けられたストレート部２０ａとで構成されている。なお、磁石挿入孔１２と同様に、ストレート部２０ａを第１部分２０ａと呼ぶことがある。２つあるストレート部２０ａの一方と凸部２０ｂとを含めて、第１部分２０ｃと呼ぶことがある。言いかえると、磁石２０のうち、回転子鉄心１０の軸心側から外周側にかけてストレートに延びる部分を含む領域を第１部分と呼ぶことがある。ただし、いずれの場合も、第１部分２０ａまたは第１部分２０ｃは、径方向の長さＡが周方向の長さＢよりも長くなるように構成されている。 外形 The outer shape of the magnet 20 is defined along the inner peripheral surface of the magnet insertion hole 12 in a top view. That is, the outer shape of the magnet 20 is U-shaped when viewed from above. The magnet 20 has a convex portion 20b that is convex toward the axis of the rotor core 10 in a state of being embedded in the magnet insertion hole 12, and a straight portion that is provided to extend straight from both ends of the convex portion 20b. 20a. Note that, like the magnet insertion hole 12, the straight portion 20a may be referred to as a first portion 20a. A portion including one of the two straight portions 20a and the protrusion 20b may be referred to as a first portion 20c. In other words, a region including a portion of the magnet 20 that extends straight from the axial center side of the rotor core 10 to the outer peripheral side may be referred to as a first portion. However, in any case, the first portion 20a or the first portion 20c is configured such that the length A in the radial direction is longer than the length B in the circumferential direction.
　図２Ｂに示すように、分割磁石２１の上面及び下面には絶縁層４０が設けられている。図示しないが、分割磁石２１の側面にも絶縁層４０が設けられている。つまり、分割磁石２１の表面全体に絶縁層４０が設けられている。従って、図２Ａに示すように、軸方向に隣り合う分割磁石２１の間には絶縁層４０が配設される。なお、絶縁層４０は、未着磁状態である分割磁石素材（以下、単に分割磁石素材という）３１の表面全体に絶縁性樹脂、例えば、エポキシ系樹脂を塗布し、さらに乾燥硬化して形成される。ただし、特にこれに限定されず、分割磁石素材３１の表面に絶縁性物質を蒸着等して形成してもよい。分割磁石素材３１を絶縁性フィルムで包装し、包装後の分割磁石素材３１を軸方向に積み重ねて磁石素材３０を構成してもよい。 絶 縁 As shown in FIG. 2B, an insulating layer 40 is provided on the upper and lower surfaces of the split magnet 21. Although not shown, the insulating layer 40 is also provided on the side surface of the split magnet 21. That is, the insulating layer 40 is provided on the entire surface of the split magnet 21. Therefore, as shown in FIG. 2A, the insulating layer 40 is provided between the divided magnets 21 adjacent in the axial direction. The insulating layer 40 is formed by applying an insulating resin, for example, an epoxy-based resin to the entire surface of a non-magnetized divided magnet material (hereinafter, simply referred to as a divided magnet material) 31, and then drying and curing the resin. You. However, the present invention is not particularly limited thereto, and the insulating material may be formed on the surface of the divided magnet material 31 by vapor deposition or the like. The magnet material 30 may be configured by wrapping the divided magnet material 31 with an insulating film and stacking the wrapped divided magnet materials 31 in the axial direction.
　なお、磁石素材３０は、ＮｄまたはＳｍ等の希土類を含む磁石粉末の焼結体であり、表面が絶縁層４０で覆われた未着磁状態の部材である。なお、磁石素材３０の材質については、特にこれに限定されず、着磁後に所望の磁力が得られるように、未着磁状態の磁石材料が所定量以上含まれていればよい。 The magnet material 30 is a sintered body of a magnet powder containing a rare earth such as Nd or Sm, and is a non-magnetized member whose surface is covered with the insulating layer 40. The material of the magnet material 30 is not particularly limited to this, and it is sufficient that the magnet material 30 contains a predetermined amount or more of the unmagnetized magnet material so that a desired magnetic force can be obtained after the magnetization.
　［回転子の組立手順］
　図３は、本発明の実施形態１に係る電動機の回転子の組立手順を示すフローチャートである。 [Rotor assembly procedure]
FIG. 3 is a flowchart showing a procedure for assembling the rotor of the electric motor according to the first embodiment of the present invention.
　まず、回転子鉄心１０を準備する（ステップＳ１）。次に、分割磁石素材３１の表面に絶縁層４０を形成し、所定の個数の分割磁石素材３１を積み重ねて磁石素材３０を準備する（ステップＳ２）。 First, the rotor core 10 is prepared (Step S1). Next, the insulating layer 40 is formed on the surface of the divided magnet material 31, and a predetermined number of divided magnet materials 31 are stacked to prepare the magnet material 30 (Step S2).
　複数ある磁石挿入孔１２のそれぞれの内周面に熱硬化性接着剤（図示せず）を塗布等して、磁石素材３０を磁石挿入孔１２内に埋設する（ステップＳ３）。さらに、磁石素材３０が埋設された回転子鉄心１０を所定の温度で加熱し、接着材を熱硬化させて磁石挿入孔１２内に磁石素材３０を位置決め固定する（ステップＳ３）。 (4) A thermosetting adhesive (not shown) is applied to the inner peripheral surface of each of the plurality of magnet insertion holes 12 to bury the magnet material 30 in the magnet insertion holes 12 (Step S3). Further, the rotor core 10 in which the magnet material 30 is embedded is heated at a predetermined temperature, the adhesive is cured by heat, and the magnet material 30 is positioned and fixed in the magnet insertion hole 12 (step S3).
　なお、ステップＳ２，Ｓ３において、表面に絶縁層４０が形成された分割磁石素材３１を磁石挿入孔１２内に順次、積み重ねるようにしてもよい。また、磁石素材３０が落下しないように、複数の磁石挿入孔１２の下面のそれぞれに接するように保持具（図示せず）が配置された状態で、ステップＳ２，Ｓ３は実行される。 In steps S2 and S3, the divided magnet materials 31 each having the insulating layer 40 formed on the surface may be sequentially stacked in the magnet insertion hole 12. Steps S2 and S3 are executed in a state in which a holder (not shown) is arranged so as to be in contact with each of the lower surfaces of the plurality of magnet insertion holes 12 so that the magnet material 30 does not drop.
　次に、着磁装置４００（図４を参照）を回転子鉄心１０の外周側に配置し、着磁装置４００で発生する所定の磁界を磁石素材３０に印加して、磁石素材３０を着磁する（ステップＳ４）。このとき、周方向において互いに隣り合う磁石２０の極性が反対向きとなるように、着磁装置４００で磁界を発生させる。 Next, a magnetizing device 400 (see FIG. 4) is arranged on the outer peripheral side of the rotor core 10, and a predetermined magnetic field generated by the magnetizing device 400 is applied to the magnet material 30 to magnetize the magnet material 30. (Step S4). At this time, the magnetizing device 400 generates a magnetic field such that the magnets 20 adjacent to each other in the circumferential direction have opposite polarities.
　図４は、本発明の実施形態１に係る電動機の回転子の組立手順の着磁工程であるステップＳ４における固定子内での磁力線の分布を示す図である。着磁装置４００は、コイル４１０に通電することで、破線で示す磁力線を発生させる。このように外部から所定の強度の磁界を印加することにより、磁石素材３０を磁化して磁石２０とすることができる。なお、隣りあうコイル４１０同士は逆巻きとなるように設けられている。コイル４１０の巻き数はいずれも同じである。コイル４１０はいずれも直列に接続されている。このようにすることで、周方向に互いに隣り合う磁石２０の極性を反対向きとし、かつ各磁石２０の磁力を同程度とすることができる。 FIG. 4 is a diagram showing the distribution of the lines of magnetic force in the stator in step S4, which is the magnetizing step of the procedure for assembling the rotor of the electric motor according to the first embodiment of the present invention. The magnetizing device 400 generates magnetic lines of force indicated by broken lines by energizing the coil 410. As described above, by applying a magnetic field having a predetermined strength from the outside, the magnet material 30 can be magnetized into the magnet 20. Note that adjacent coils 410 are provided so as to be reversely wound. The number of turns of the coil 410 is the same. The coils 410 are all connected in series. By doing so, the polarities of the magnets 20 adjacent to each other in the circumferential direction can be made opposite directions, and the magnetic force of each magnet 20 can be made substantially the same.
　回転子鉄心１０の貫通開口１１に回転軸５０を圧入して取付固定する（ステップＳ５）。このようにして、回転子１００の組立が完了する。 (4) The rotating shaft 50 is press-fitted into the through-opening 11 of the rotor core 10 and fixedly attached (step S5). Thus, the assembly of the rotor 100 is completed.
　［効果等］
　以上説明したように、本実施形態に係る回転子１００は、回転軸５０と、周方向に所定の間隔をあけて設けられた複数の磁石挿入孔１２を有する回転子鉄心１０と、磁石挿入孔１２のそれぞれに埋設された磁石２０と、を少なくとも備えている。 [Effects]
As described above, the rotor 100 according to the present embodiment includes the rotor core 10 having the rotating shaft 50, the plurality of magnet insertion holes 12 provided at predetermined intervals in the circumferential direction, and the magnet insertion hole. And a magnet 20 embedded in each of the twelve.
　磁石２０は、軸方向に積み複数重ねられて埋設された分割磁石２１からなる。なお、分割磁石２１は、分割磁石素材３１が外部から着磁されてなる。 The magnet 20 is composed of divided magnets 21 which are stacked and buried in the axial direction. The divided magnet 21 is formed by magnetizing a divided magnet material 31 from the outside.
　磁石挿入孔１２は、上面視で回転子鉄心１０の外周側から軸心側にかけて延びるように設けられ、かつ径方向の長さが周方向の長さよりも長い第１部分１２ａまたは第１部分１２ｃを有している。また、軸方向に隣り合う分割磁石２１の間に、絶縁層４０が設けられている。 The magnet insertion hole 12 is provided so as to extend from the outer peripheral side to the axial center side of the rotor core 10 in a top view, and the first portion 12a or the first portion 12c whose radial length is longer than the circumferential length. have. An insulating layer 40 is provided between the divided magnets 21 adjacent in the axial direction.
　回転子１００をこのように構成することで、磁石挿入孔１２及びこれに埋設される磁石素材３０が、回転子鉄心１０の外周側から軸心に近い側まで延びるように設けられている場合に、軸心に近い側に位置する部分も含めて、１回の着磁工程で磁石素材３０を十分に磁化することができる。このことについてさらに説明する。 By configuring the rotor 100 in this manner, when the magnet insertion hole 12 and the magnet material 30 embedded in the magnet insertion hole 12 are provided so as to extend from the outer peripheral side of the rotor core 10 to a side closer to the axis, In addition, the magnet material 30 can be sufficiently magnetized in one magnetizing step, including the portion located on the side closer to the axis. This will be further described.
　図５は、本発明の実施形態１に係る電動機の回転子外周からの径方向の距離と磁石の着磁率との関係を示す図である。なお、図５は、図４に示す着磁装置４００を用いて４０００μＦ、４０００Ｖの条件で着磁を行なった結果を示している。図５に示す横軸方向の点線は、磁石２０の要求性能を満たすために必要な着磁率α（％）を示している。ここでは、約９０％の着磁率に対応する。ただし、回転子１００に要求される性能仕様等によって、着磁率αは９０％より高い場合も低い場合もありうる。 FIG. 5 is a diagram showing the relationship between the radial distance from the outer periphery of the rotor of the electric motor according to the first embodiment of the present invention and the magnetization rate of the magnet. FIG. 5 shows the result of magnetizing using the magnetizing device 400 shown in FIG. 4 under the conditions of 4000 μF and 4000 V. The dotted line in the horizontal axis direction shown in FIG. 5 indicates the magnetization ratio α (%) necessary to satisfy the required performance of the magnet 20. Here, it corresponds to a magnetization rate of about 90%. However, the magnetization rate α may be higher or lower than 90% depending on the performance specifications required for the rotor 100 and the like.
　図５に示すデータを取得するにあたって、直径が１０８ｍｍ、軸方向の高さが５５ｍｍの回転子鉄心１０を用いた。磁石２０は、ストレート部２０ａの先端から凸部２０ｂの先端までの長さが２５ｍｍのものを用いた。磁石２０の軸方向の長さは、分割の有無にかかわらず、磁石挿入孔１２の軸方向の長さ、言いかえると、回転子鉄心１０の軸方向の長さに実質的に等しくなるようにした。よって、磁石２０が１０枚積層された分割磁石２１で構成される場合には、分割磁石２１の各々は、軸方向の高さを５．４６ｍｍとした。絶縁層４０として、膜厚２０μｍのエポキシ系樹脂を分割磁石２１の表面、実際には分割磁石素材３１の表面に形成した。図５に示す例では、図１に示す６極の回転子１００ではなく、磁石が１０箇所に埋設された１０極の回転子１００を用いて着磁率の比較を行った。 (5) In obtaining the data shown in FIG. 5, a rotor core 10 having a diameter of 108 mm and an axial height of 55 mm was used. The magnet 20 used had a length of 25 mm from the tip of the straight portion 20a to the tip of the projection 20b. The length of the magnet 20 in the axial direction is substantially equal to the length of the magnet insertion hole 12 in the axial direction, in other words, the length of the rotor core 10 in the axial direction regardless of the division. did. Therefore, in the case where the magnet 20 is composed of the ten divided magnets 21 stacked, each of the divided magnets 21 has an axial height of 5.46 mm. As the insulating layer 40, an epoxy resin having a thickness of 20 μm was formed on the surface of the divided magnet 21, actually, on the surface of the divided magnet material 31. In the example shown in FIG. 5, the magnetizing ratios were compared using a 10-pole rotor 100 in which magnets were buried at 10 places, instead of the 6-pole rotor 100 shown in FIG.
　なお、ここで言う着磁率とは、上記の着磁を実施した後、回転子１００から磁石２０を引抜き、回転子１００の外周側から軸心側に沿って磁石２０の磁束密度を計測し、外周側先端にある磁石の磁束密度を分母として計算した値である。 Note that the magnetization rate referred to here means that after performing the above-described magnetization, the magnet 20 is pulled out of the rotor 100, and the magnetic flux density of the magnet 20 is measured from the outer peripheral side of the rotor 100 to the axial center side. This is a value calculated by using the magnetic flux density of the magnet at the outer peripheral end as a denominator.
　図５から明らかなように、磁石２０が未分割の場合、ストレート部２０ａの先端から軸心側に向かって７ｍｍ程度の領域までは、着磁率がα以上であるが、これを越えると着磁率が急激に低下した。２分割の磁石２０では、着磁率がα以上となる領域はストレート部２０ａの先端から軸心側に向かって１０ｍｍ程度である。磁石２０を１０分割した場合は、着磁率がα以上となる領域はストレート部２０ａの先端から軸心側に向かって２２ｍｍ程度である。つまり、磁石２０の軸心側先端に近い部分までα以上の着磁率で着磁可能であった。 As is apparent from FIG. 5, when the magnet 20 is not divided, the magnetizability is equal to or more than α from the tip of the straight portion 20a to the region of about 7 mm toward the axial center side. Dropped sharply. In the two-part magnet 20, the region where the magnetization rate is equal to or more than α is about 10 mm from the tip of the straight portion 20a toward the axis. When the magnet 20 is divided into ten, the region where the magnetization ratio is equal to or more than α is about 22 mm from the tip of the straight portion 20a toward the axis. That is, it was possible to magnetize the magnet 20 with a magnetization rate of α or more up to a portion near the axial center end.
　これは、磁石２０の分割状態によって、磁石２０の表面に発生する渦電流とこれに伴う反磁界との発生状態が異なることに起因していると考えられる。 This is considered to be due to the fact that the state of generation of the eddy current generated on the surface of the magnet 20 and the demagnetizing field accompanying the eddy current differ depending on the state of division of the magnet 20.
　図６は、本発明の実施形態１に係る電動機の磁石の分割の有無による磁石での渦電流及び反磁界の発生状態を示す模式図である。なお、説明の便宜上、図６において、磁石２０の側面を平面として図示している。 FIG. 6 is a schematic diagram showing the state of generation of an eddy current and a demagnetizing field in a magnet according to the first embodiment of the present invention, depending on whether the magnet is divided or not. For convenience of explanation, FIG. 6 shows the side surface of the magnet 20 as a plane.
　所定の方向に外部磁界が印加されると、外部磁界の方向と交差する磁石２０の側面には所定の回転方向に渦電流が流れ、外部磁界に対して反対向きに反磁界が発生する。図６の（ａ）に示すように、磁石２０が軸方向で分割されていない場合、磁石２０の側面全体に渦電流が流れる。このため、その電流量は大きくなり、電流量の増加に伴って反磁界も強度が増す。一方、図１に示すように、磁石２０のうち、凸部２０ｂの径方向外側には所定の体積の回転子鉄心１０が存在するため、この部分で着磁時の外部磁界が弱められることは上述の通りである。 (4) When an external magnetic field is applied in a predetermined direction, an eddy current flows in a predetermined rotation direction on a side surface of the magnet 20 that intersects the direction of the external magnetic field, and a demagnetizing field is generated in a direction opposite to the external magnetic field. As shown in FIG. 6A, when the magnet 20 is not divided in the axial direction, an eddy current flows on the entire side surface of the magnet 20. For this reason, the current amount increases, and the strength of the demagnetizing field also increases with the increase in the current amount. On the other hand, as shown in FIG. 1, the rotor 20 having a predetermined volume exists radially outside the protrusion 20 b of the magnet 20, so that the external magnetic field during magnetization is weakened in this portion. As described above.
　しかし、反磁界は渦電流の電流量に依存し、磁石２０の側面全体で一様であるから、凸部２０ｂにおいて、ストレート部２０ａよりもさらに着磁時の外部磁界が弱められる。このため、軸心側での着磁率が大きく低下するものと考えられる。 However, since the demagnetizing field depends on the amount of the eddy current and is uniform on the entire side surface of the magnet 20, the external magnetic field at the time of magnetization is further weakened in the convex portion 20b than in the straight portion 20a. For this reason, it is considered that the magnetization rate on the axial center side is greatly reduced.
　一方、本実施形態によれば、図６の（ｂ）に示すように、磁石２０を軸方向に積み重ねられた複数の分割磁石２１で構成するとともに、軸方向に隣り合う分割磁石２１の間に絶縁層４０を設けている。このことにより、分割磁石２１の各々で発生する渦電流の電流量を小さくして、反磁界を弱められる。よって、凸部２０ｂにおいて、着磁時の外部磁界が弱められるのを抑制し、より少ない回数、例えば１回の着磁で磁石素材３０を磁化して磁石２０にすることができる。また、着磁装置４００の簡素化及び組立時のリードタイムの低減を図ることができる。したがって、回転子１００の製造コストを低減できる。 On the other hand, according to the present embodiment, as shown in FIG. 6B, the magnet 20 is configured by a plurality of divided magnets 21 stacked in the axial direction, and between the divided magnets 21 adjacent in the axial direction. An insulating layer 40 is provided. As a result, the amount of eddy current generated in each of the divided magnets 21 can be reduced, and the demagnetizing field can be reduced. Therefore, it is possible to suppress the external magnetic field at the time of magnetization from being weakened at the convex portion 20b, and magnetize the magnet material 30 by a smaller number of times, for example, once, to form the magnet 20. Further, simplification of the magnetizing device 400 and reduction of the lead time during assembly can be achieved. Therefore, the manufacturing cost of the rotor 100 can be reduced.
　さらに、回転子鉄心１０に対して、高体積密度でかつ、利用効率が高められた複数の磁石２０を配置できる。このため、本実施形態の回転子１００を電動機３００に適用すると、より高い回転トルクを得ることができる。また、同じ回転トルクであれば、回転子１００の体積を小さくできる。 Furthermore, a plurality of magnets 20 having a high volume density and improved utilization efficiency can be arranged on the rotor core 10. For this reason, when the rotor 100 of the present embodiment is applied to the electric motor 300, higher rotation torque can be obtained. Further, with the same rotational torque, the volume of the rotor 100 can be reduced.
　また、本実施形態の回転子１００によれば、複数の分割磁石素材３１を磁石挿入孔１２内に軸方向に積み重ねた状態で着磁して磁石２０とするため、磁石挿入孔１２内へ分割磁石素材３１の配置を容易に行うことができる。これにより、組立工程の簡素化を図ることができる。 Further, according to the rotor 100 of the present embodiment, since the magnet 20 is magnetized in a state where the plurality of divided magnet materials 31 are stacked in the magnet insertion hole 12 in the axial direction, the magnet 20 is divided into the magnet insertion hole 12. The arrangement of the magnet material 31 can be easily performed. Thereby, the assembly process can be simplified.
　また、着磁済の磁石を回転子鉄心１０内に配置する場合、磁力によって鉄屑等の異物が磁石に吸着されることがある。このような異物は、磁石を磁石挿入孔１２内に配置する場合の障害物となり、回転子１００の組立不良等を引き起こすおそれがあった。 When a magnetized magnet is arranged in the rotor core 10, foreign matter such as iron chips may be attracted to the magnet by the magnetic force. Such a foreign substance becomes an obstacle when the magnet is arranged in the magnet insertion hole 12, and may cause an assembly failure of the rotor 100 or the like.
　一方、本実施形態の回転子１００によれば、複数の分割磁石素材３１を磁石挿入孔１２内に配置するため、磁力による異物の吸着が起こらず、組立不良等が発生するのを防止することができる。また、分割磁石素材３１は未着磁状態であるため、磁力によって回転子鉄心１０に引き寄せられることなく、磁石挿入孔１２内に配置することができる。このことにより、分割磁石２１の表面に設けられた絶縁層４０が回転子鉄心１０と擦れ合って剥がれることを防止することができる。したがって、回転子１００の組立歩留まりを向上することができる。 On the other hand, according to the rotor 100 of the present embodiment, since the plurality of divided magnet materials 31 are arranged in the magnet insertion holes 12, it is possible to prevent a foreign material from being attracted by a magnetic force and to prevent an assembly failure or the like from occurring. Can be. Further, since the divided magnet material 31 is not magnetized, it can be arranged in the magnet insertion hole 12 without being attracted to the rotor core 10 by a magnetic force. Thus, it is possible to prevent the insulating layer 40 provided on the surface of the split magnet 21 from rubbing against the rotor core 10 and coming off. Therefore, the assembly yield of the rotor 100 can be improved.
　また、磁石挿入孔１２は、上面視で回転子鉄心１０の軸心に向かって凸形状である。磁石２０の外形は、上面視で磁石挿入孔１２の内周面に沿うように規定されている。これにより、回転子鉄心１０内での占有密度が高められた複数の磁石挿入孔１２のそれぞれに対して、高い充填率で磁石２０を配置することができる。ひいては、電動機３００の回転トルクを高めることができる。 The magnet insertion hole 12 has a convex shape toward the axis of the rotor core 10 in a top view. The outer shape of the magnet 20 is defined along the inner peripheral surface of the magnet insertion hole 12 in a top view. Thus, the magnets 20 can be arranged at a high filling rate in each of the plurality of magnet insertion holes 12 whose occupation density in the rotor core 10 is increased. Consequently, the rotational torque of the electric motor 300 can be increased.
　また、磁石２０の外形を上記の形状とすることで、磁石素材３０の側面と着磁装置４００から発生する磁力線とが直交する。このため、磁石素材３０の磁化が容易になる。このことにより、凸部２０ｂの最深部すなわち軸心側に近い磁石２０の着磁率が向上し、磁石２０の利用効率を高められる。また、電動機３００の回転トルクを高めることができる。 Further, by making the outer shape of the magnet 20 into the above shape, the side surfaces of the magnet material 30 and the magnetic force lines generated from the magnetizing device 400 are orthogonal to each other. Therefore, the magnetization of the magnet material 30 becomes easy. As a result, the magnetizing rate of the magnet 20 near the deepest part of the projection 20b, that is, near the axis, is improved, and the utilization efficiency of the magnet 20 can be increased. Further, the rotation torque of the electric motor 300 can be increased.
　また、本実施形態の回転子１００は、上面視で、複数の磁石のうち、周方向に隣り合う２つの磁石２０をそれぞれ通るｄ軸磁束通路６０と、複数の磁石２０の径方向外側に位置する回転子鉄心１０を通るｑ軸磁束通路６１とが形成され、磁気的突極性を有している。 In addition, the rotor 100 of the present embodiment has a d-axis magnetic flux path 60 that passes through two magnets 20 that are adjacent to each other in the circumferential direction among the plurality of magnets, and is positioned radially outside the plurality of magnets 20 when viewed from above. And a q-axis magnetic flux passage 61 that passes through the rotor core 10 having a magnetic saliency.
　本実施形態によれば、ｄ軸磁束通路６０に起因するマグネットトルクとｑ軸磁束通路６１に起因するリラクタンストルクとの両方を電動機３００の回転トルクとして利用でき、回転トルクを高めることができる。 According to the present embodiment, both the magnet torque caused by the d-axis magnetic flux passage 60 and the reluctance torque caused by the q-axis magnetic flux passage 61 can be used as the rotation torque of the electric motor 300, and the rotation torque can be increased.
　また、本実施形態の電動機３００は、回転子１００と、回転子１００の径方向外側に、回転子１００と所定の間隔をあけて配設された固定子２００と、を備えている。 In addition, the electric motor 300 of the present embodiment includes the rotor 100, and the stator 200 disposed radially outside the rotor 100 with a predetermined interval from the rotor 100.
　本実施形態によれば、回転子１００のコストを低減できるとともに、磁石２０の利用効率を高めることができる。したがって、高い回転トルクの電動機３００を実現できる。 According to the present embodiment, the cost of the rotor 100 can be reduced, and the utilization efficiency of the magnet 20 can be increased. Therefore, the electric motor 300 with high rotational torque can be realized.
　＜変形例＞
　図７Ａは、変形例に係る回転子１００を示す断面模式図である。図７Ｂは、別の変形例に係る回転子１００を示す断面模式図である。図７Ｃは、さらなる別の変形例に係る回転子１００を示す断面模式図である。なお、実施形態１と同様の箇所については同一の符号を付し、詳細な説明を省略する。 <Modification>
FIG. 7A is a schematic sectional view showing a rotor 100 according to a modification. FIG. 7B is a schematic sectional view showing a rotor 100 according to another modification. FIG. 7C is a schematic cross-sectional view showing a rotor 100 according to still another modification. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description will be omitted.
　図７Ａ，図７Ｂに示すように、磁石挿入孔１２及び磁石２０の形状を、上面視で、回転子鉄心１０の軸心側に向かって凸となるＶ字形状としてもよい。また、図７Ｃに示すように、磁石挿入孔１２及び磁石２０の個々の形状を、上面視で、回転子鉄心１０の外周側から軸心側に向かって延びる長方形状とし、全体として、いわゆるスポーク形状となるようにしてもよい。 As shown in FIGS. 7A and 7B, the shape of the magnet insertion hole 12 and the magnet 20 may be a V-shape that is convex toward the axis of the rotor core 10 in a top view. Further, as shown in FIG. 7C, the individual shapes of the magnet insertion hole 12 and the magnet 20 are rectangular shapes extending from the outer peripheral side of the rotor core 10 toward the axial center side in a top view. You may make it become a shape.
　回転子１００をこのように構成しても実施形態１と同様の効果を得ることができる。本変形例においても、磁石挿入孔１２の径方向の長さＡは周方向の長さＢよりも長くなるようにしている。周方向で互いに隣り合う磁石２０の極性も反対向きである。 し て も Even if the rotor 100 is configured in this manner, the same effect as in the first embodiment can be obtained. Also in this modification, the radial length A of the magnet insertion hole 12 is set to be longer than the circumferential length B. The polarities of the magnets 20 adjacent to each other in the circumferential direction are also opposite.
　なお、特に図示しないが、磁石挿入孔１２と磁石２０との間には隙間が生じている。この隙間は、磁石２０の寸法公差と回転子鉄心１０を構成する電磁鋼板の寸法公差とから自ずと生じるクリアランスである。また、磁石２０のＮ極とＳ極とが回転子鉄心１０を介して磁気的に短絡するのを回避するために、磁石挿入孔１２と磁石２０との間にやや幅広な隙間を配置する場合もある。この幅広な隙間は、所謂、フラックスバリアと呼称される。フラックスバリアは、磁石挿入孔１２を部分的に磁石２０よりも大きい形状とするもので、上記の寸法公差に起因するクリアランスよりも大きな寸法の隙間を構成するのが一般的で、公知の構成である。 Although not particularly shown, a gap is formed between the magnet insertion hole 12 and the magnet 20. This gap is a clearance naturally generated due to the dimensional tolerance of the magnet 20 and the dimensional tolerance of the electromagnetic steel sheet constituting the rotor core 10. Further, in order to avoid a magnetic short circuit between the N pole and the S pole of the magnet 20 via the rotor core 10, a case where a slightly wide gap is arranged between the magnet insertion hole 12 and the magnet 20. There is also. This wide gap is called a so-called flux barrier. The flux barrier has a shape in which the magnet insertion hole 12 is partially larger than the magnet 20, and generally forms a gap having a dimension larger than the clearance caused by the dimensional tolerance described above. is there.
　（実施形態２）
　図８は、本発明の実施形態２に係る磁石２０を示す斜視図である。図９は、本発明の実施形態２に係る別の磁石２０を示す斜視図である。図８に示す磁石２０は、図２Ａに示す構成に対応している。図９に示す磁石２０は、図７Ｃに示す構成に対応している。なお、実施形態１と同様の箇所については同一の符号を付し、詳細な説明を省略する。 (Embodiment 2)
FIG. 8 is a perspective view showing a magnet 20 according to the second embodiment of the present invention. FIG. 9 is a perspective view showing another magnet 20 according to the second embodiment of the present invention. The magnet 20 shown in FIG. 8 corresponds to the configuration shown in FIG. 2A. The magnet 20 shown in FIG. 9 corresponds to the configuration shown in FIG. 7C. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description will be omitted.
　本実施形態に示す構成と実施形態１に示す構成とでは、以下の点で異なる。図８および図９において、磁石２０は、上面視で複数箇所に分割されている。回転子鉄心１０の軸心に近い側に位置する第１磁石２２は軸方向に分割される。回転子鉄心１０の外周側に位置する第２磁石２３は軸方向に分割されていない非分割の磁石である。磁石２０の分割箇所のそれぞれに絶縁層４０が設けられている。 構成 The configuration shown in the present embodiment is different from the configuration shown in the first embodiment in the following points. 8 and 9, the magnet 20 is divided into a plurality of portions when viewed from above. The first magnet 22 located on the side closer to the axis of the rotor core 10 is divided in the axial direction. The second magnet 23 located on the outer peripheral side of the rotor core 10 is a non-divided magnet that is not divided in the axial direction. An insulating layer 40 is provided at each of the divided portions of the magnet 20.
　言いかえると、磁石挿入孔１２の第１部分１２ａまたは第１部分１２ｃに埋設された磁石２０のうち、回転子鉄心１０の軸心に近い側に位置する第１磁石２２は、磁石挿入孔１２内に軸方向に積み重ねられた複数の分割磁石２２ａで構成されている。軸方向に隣り合う分割磁石２２ａの間に絶縁層４０が設けられている。回転子鉄心１０の外周に近い側に位置する第２磁石２３は軸方向に非分割である。第２磁石２３は、磁石挿入孔１２内で絶縁層４０を挟んで第１磁石２２と径方向で接して設けられている。 In other words, of the magnets 20 embedded in the first portion 12a or the first portion 12c of the magnet insertion hole 12, the first magnet 22 located closer to the axis of the rotor core 10 is the magnet insertion hole 12 And a plurality of divided magnets 22a stacked in the axial direction. The insulating layer 40 is provided between the divided magnets 22a adjacent in the axial direction. The second magnet 23 located on the side close to the outer periphery of the rotor core 10 is not divided in the axial direction. The second magnet 23 is provided in radial contact with the first magnet 22 with the insulating layer 40 interposed in the magnet insertion hole 12.
　磁石２０は、第１磁石２２及び第２磁石２３を含め、磁石挿入孔１２の第１部分１２ａまたは第１部分１２ｃに埋設されている。磁石２０は複数の分割磁石素材３１が外部から着磁されてなる。 The magnet 20, including the first magnet 22 and the second magnet 23, is embedded in the first portion 12a or the first portion 12c of the magnet insertion hole 12. The magnet 20 is formed by magnetizing a plurality of divided magnet materials 31 from the outside.
　回転子１００の磁石２０をこのように構成することで、実施形態１と同様に、軸心に近い側の第１磁石２２を容易に磁化できるとともに、外周側に近い第２磁石２３の減磁を抑制することができる。このことについてさらに説明する。 By configuring the magnet 20 of the rotor 100 in this way, the first magnet 22 near the axis can be easily magnetized and the demagnetization of the second magnet 23 near the outer periphery side, as in the first embodiment. Can be suppressed. This will be further described.
　磁石挿入孔１２内に配置される磁石２０を軸方向で分割し、かつ軸方向に隣り合う分割磁石２１の間に絶縁層４０を設けることで、図６の（ｂ）に示すように、分割磁石２１のそれぞれに生じる渦電流を低減できるとともに、外部磁界と反対向きに発生する反磁界を弱められる。このことは、磁石素材３０を磁化する場合には有利に働くが、以下で説明する別の課題が発生しうる。 As shown in FIG. 6B, the magnet 20 arranged in the magnet insertion hole 12 is divided in the axial direction, and the insulating layer 40 is provided between the divided magnets 21 adjacent in the axial direction. The eddy current generated in each of the magnets 21 can be reduced, and the demagnetizing field generated in the direction opposite to the external magnetic field can be reduced. This is advantageous when the magnet material 30 is magnetized, but may cause another problem described below.
　図１に示す電動機３００が動作する場合、固定子２００によって回転磁界が発生することは上述の通りである。一方、固定子２００からの回転磁界によって保磁力以上の磁界が磁石２０に加わると磁石２０の磁化が急激に低下する。いわゆる減磁という現象である。減磁は、固定子２００からの磁界強度が高い回転子鉄心１０の外周側でより顕著に起こりうる。 As described above, when the electric motor 300 shown in FIG. 1 operates, a rotating magnetic field is generated by the stator 200. On the other hand, when a magnetic field equal to or more than the coercive force is applied to the magnet 20 by the rotating magnetic field from the stator 200, the magnetization of the magnet 20 sharply decreases. This is a phenomenon called demagnetization. The demagnetization can occur more remarkably on the outer peripheral side of the rotor core 10 where the magnetic field strength from the stator 200 is high.
　一方、外部から磁界が印加されると、磁石２０の表面には渦電流を生じ、この電流量に応じて、外部磁界とは反対向きの反磁界が磁石２０に発生することは既に述べたとおりである。反磁界の発生によって、磁石２０の減磁は緩和される。 On the other hand, when a magnetic field is applied from the outside, an eddy current is generated on the surface of the magnet 20, and a demagnetizing field in the direction opposite to the external magnetic field is generated in the magnet 20 in accordance with the amount of the current, as described above. It is. Due to the generation of the demagnetizing field, the demagnetization of the magnet 20 is reduced.
　しかし、図２Ａに示すように、磁石２０を複数の分割磁石２１で構成し、軸方向に隣り合う分割磁石２１の間に絶縁層４０を設けると、分割磁石２１の各々で発生する渦電流、ひいては反磁界は小さいものとなってしまう。このため、固定子２００で発生する磁界強度または磁石２０の保磁力の設定値等によっては、非分割の磁石よりも回転子鉄心外周側に近い側で減磁しやすくなる。これにより、電動機３００の性能、例えば、回転トルク等が低下してしまうことがありうる。 However, as shown in FIG. 2A, when the magnet 20 is composed of a plurality of divided magnets 21 and the insulating layer 40 is provided between the divided magnets 21 adjacent in the axial direction, the eddy current generated in each of the divided magnets 21 is reduced. As a result, the demagnetizing field becomes small. For this reason, depending on the strength of the magnetic field generated in the stator 200 or the set value of the coercive force of the magnet 20, demagnetization is more likely to occur on the side closer to the outer periphery of the rotor core than the undivided magnet. As a result, the performance of the electric motor 300, for example, the rotational torque may be reduced.
　一方、本実施形態によれば、回転子鉄心１０の外周側に位置する第２磁石２３を軸方向に非分割の磁石とすることで、第２磁石２３で発生する渦電流及びこれに応じた反磁界を強めることができる。これにより、固定子２００からの磁界により、第２磁石２３が減磁されるのを抑制できる。また、回転子鉄心１０の軸心側に位置する第１磁石２２を実施形態１と同様とし、第２磁石２３と第１磁石２２との間に絶縁層４０を設けることで、第１磁石２２の着磁率を向上して、磁石２０の利用効率を高めることができる。これにより、高い回転トルクの電動機３００を実現できる。 On the other hand, according to the present embodiment, the second magnet 23 located on the outer peripheral side of the rotor core 10 is a non-split magnet in the axial direction, so that the eddy current generated in the second magnet 23 and the The demagnetizing field can be strengthened. Thereby, the second magnet 23 can be prevented from being demagnetized by the magnetic field from the stator 200. Further, the first magnet 22 located on the axis side of the rotor core 10 is the same as in the first embodiment, and the insulating layer 40 is provided between the second magnet 23 and the first magnet 22 so that the first magnet 22 And the utilization efficiency of the magnet 20 can be increased. Thereby, the electric motor 300 with high rotation torque can be realized.
　なお、第２磁石２３の径方向外側に位置する回転子鉄心１０の体積は小さいため、着磁の際に外部磁界が十分に磁石素材３０内に進入する。このため、第２磁石２３で発生する渦電流が大きくなっても、１回の着磁で十分に第２磁石２３を磁化できる。 Since the volume of the rotor core 10 located radially outside the second magnet 23 is small, an external magnetic field sufficiently enters the magnet material 30 during magnetization. For this reason, even if the eddy current generated in the second magnet 23 increases, the second magnet 23 can be sufficiently magnetized by one magnetization.
　なお、磁石挿入孔１２の第１部分１２ａまたは第１部分１２ｃに埋設された第１磁石２２及び第２磁石２３の外形は、上面視で第１部分１２ａまたは第１部分１２ｃの内周面に沿うように規定されている。 The outer shapes of the first magnet 22 and the second magnet 23 embedded in the first portion 12a or the first portion 12c of the magnet insertion hole 12 are formed on the inner peripheral surface of the first portion 12a or the first portion 12c in a top view. It is specified to follow.
　このようにすることで、実施形態１と同様に、高い充填率で磁石２０を配置することができる。よって、電動機３００の回転トルクを高めることができる。 こ と By doing so, the magnets 20 can be arranged at a high filling rate, as in the first embodiment. Therefore, the rotation torque of electric motor 300 can be increased.
　本実施形態によれば、磁石２０における絶縁層４０の割合が低減する。このため、磁力を発生させる焼結体の割合が大きくなる。したがって、磁石２０の磁力を向上させることができる。 According to the present embodiment, the ratio of the insulating layer 40 in the magnet 20 is reduced. For this reason, the ratio of the sintered body that generates a magnetic force increases. Therefore, the magnetic force of the magnet 20 can be improved.
　第１磁石２２の径方向の長さＬ１と第２磁石２３の径方向の長さＬ２との比は、磁石２０の磁化のしやすさまたは減磁の度合い等に応じて設定される。第２磁石２３は軸方向に非分割でなくてもよく、分割されていてもよい。ただし、その場合に、第２磁石２３の側面の表面積は、第１磁石２２における１つの分割磁石２２ａの側面の表面積よりも大きくなるようにする。このようにすることで、第２磁石２３で発生する渦電流及び反磁界を高め、第２磁石２３が減磁されるのを抑制することができる。また、第２磁石２３が軸方向に非分割、言いかえると、第２磁石２３の軸方向の長さが磁石挿入孔１２の軸方向の長さに実質的に等しくなるようにすると、減磁の抑制度合いが向上するのは言うまでもない。 比 The ratio of the radial length L1 of the first magnet 22 to the radial length L2 of the second magnet 23 is set in accordance with the ease of magnetization of the magnet 20, the degree of demagnetization, and the like. The second magnet 23 does not have to be non-divided in the axial direction, and may be divided. However, in this case, the surface area of the side surface of the second magnet 23 is set to be larger than the surface area of the side surface of one divided magnet 22a in the first magnet 22. By doing so, the eddy current and the demagnetizing field generated in the second magnet 23 can be increased, and the demagnetization of the second magnet 23 can be suppressed. When the second magnet 23 is not divided in the axial direction, in other words, when the axial length of the second magnet 23 is made substantially equal to the axial length of the magnet insertion hole 12, demagnetization is achieved. Needless to say, the degree of suppression is improved.
　以上のように、本実施形態の回転子１００は、回転軸５０と、外周に沿った周方向に所定の間隔をあけて設けられた複数の磁石挿入孔１２を有する回転子鉄心１０と、複数の磁石挿入孔１２のそれぞれに埋設された磁石２０と、を備える。複数の磁石挿入孔１２の各々は、上面視で回転子鉄心１０の外周側から回転子鉄心１０の軸心側にかけて延びるように設けられた第１部分１２ｃを有する。磁石２０は、第１部分１２ｃに埋設され、回転子鉄心１０の軸心に近い側に位置する第１磁石２２を含み、第１磁石２２は、回転軸５０の延びる軸方向に積み重ねられた複数の分割磁石２１で構成される。軸方向に隣り合う複数の分割磁石２１の間に絶縁層４０が設けられている。磁石２０は、第１部分１２ｃに埋設され、回転子鉄心１０の外周に近い側に位置する第２磁石２３を含み、第２磁石２３の側面の表面積は、第１磁石２２における１つの分割磁石２１の側面の表面積よりも大きい。第２磁石２３は、複数の磁石挿入孔１２内で絶縁層４０を挟んで第１磁石２２と回転子鉄心の半径方向１０である径方向で接して設けられている。 As described above, the rotor 100 according to the present embodiment includes the rotor core 10 having the plurality of magnet insertion holes 12 provided at predetermined intervals in the circumferential direction along the outer circumference, And a magnet 20 buried in each of the magnet insertion holes 12. Each of the plurality of magnet insertion holes 12 has a first portion 12c provided to extend from the outer peripheral side of the rotor core 10 to the axial center side of the rotor core 10 in a top view. The magnet 20 includes a first magnet 22 buried in the first portion 12 c and located on a side closer to the axis of the rotor core 10, and the first magnet 22 includes a plurality of magnets stacked in the axial direction in which the rotation shaft 50 extends. Of the divided magnet 21. The insulating layer 40 is provided between the plurality of divided magnets 21 adjacent in the axial direction. The magnet 20 includes a second magnet 23 buried in the first portion 12 c and located on a side near the outer periphery of the rotor core 10, and a surface area of a side surface of the second magnet 23 is one divided magnet of the first magnet 22. 21 is larger than the surface area of the side surface. The second magnet 23 is provided in contact with the first magnet 22 in the radial direction which is the radial direction 10 of the rotor core with the insulating layer 40 interposed in the plurality of magnet insertion holes 12.
　この構成によれば、第１磁石２２において、軸方向に隣り合う分割磁石２１の間に絶縁層４０を設けることで、分割磁石２１のそれぞれで発生する渦電流を低減して、着磁率が低下するのを抑制できる。したがって、第１磁石２２の利用効率を高められる。また、第２磁石２３の表面積が第１磁石２２における１つの分割磁石２１の表面積よりも大きくなるようにすることで、固定子２００からの磁界によって第２磁石２３が減磁される度合いを小さくすることができる。また、第２磁石２３における絶縁層４０の比率を低減できる。このため、磁石全体の磁力を向上できる。 According to this configuration, in the first magnet 22, by providing the insulating layer 40 between the divided magnets 21 adjacent in the axial direction, the eddy current generated in each of the divided magnets 21 is reduced, and the magnetization rate is reduced. Can be suppressed. Therefore, the utilization efficiency of the first magnet 22 can be increased. Further, by making the surface area of the second magnet 23 larger than the surface area of one divided magnet 21 in the first magnet 22, the degree of demagnetization of the second magnet 23 by the magnetic field from the stator 200 is reduced. can do. Further, the ratio of the insulating layer 40 in the second magnet 23 can be reduced. For this reason, the magnetic force of the whole magnet can be improved.
　（その他の実施形態）
　変形例を含む実施形態１，２において、回転子１００は、回転子鉄心１０内に磁石２０が６個配置された６極構成である。しかし、特にこれに限定されない。例えば、１０極構成であってもよい。また、４極構成または１２極構成等であってもよく、本発明においては、特に極数に関する構成は限定しない。その場合は、固定子２００の歯部２２０及び界磁コイル２４０の数等も適宜変更される。 (Other embodiments)
In the first and second embodiments including the modified example, the rotor 100 has a six-pole configuration in which six magnets 20 are arranged in the rotor core 10. However, it is not particularly limited to this. For example, a 10-pole configuration may be used. Further, a four-pole configuration or a twelve-pole configuration may be used. In the present invention, a configuration relating to the number of poles is not particularly limited. In that case, the number of the teeth 220 of the stator 200 and the number of the field coils 240 are appropriately changed.
　実施形態１，２において、分割磁石素材３１を磁石挿入孔１２内に配置した後、外部から着磁して分割磁石２１を得ている。しかし、着磁済の分割磁石２１を磁石挿入孔１２内に配置し、回転子１００を得ることも可能である。 In the first and second embodiments, the divided magnet material 31 is disposed in the magnet insertion hole 12 and then magnetized from the outside to obtain the divided magnet 21. However, it is also possible to arrange the magnetized split magnet 21 in the magnet insertion hole 12 to obtain the rotor 100.
　本発明の回転子は、磁石の利用効率を高めて回転トルクを向上でき、電動機に適用する上で有用である。 回 転 The rotor of the present invention can improve the rotational efficiency by increasing the utilization efficiency of the magnet, and is useful when applied to an electric motor.
１０　　回転子鉄心
１１　　貫通開口
１２　　磁石挿入孔
１２ａ　ストレート部（第１部分）
１２ｂ　凸部
１２ｃ　第１部分
２０　　磁石
２０ａ　ストレート部（第１部分）
２０ｂ　凸部
２０ｃ　第１部分
２１　　分割磁石
２２　　第１磁石
２２ａ　分割磁石
２３　　第２磁石
３０　　磁石素材
３１　　分割磁石素材
４０　　絶縁層
５０　　回転軸（出力軸）
６０　　ｄ軸磁束通路
６１　　ｑ軸磁束通路
１００　回転子
２００　固定子
２１０　ヨーク部
２２０　歯部
２３０　磁心
２４０　界磁コイル
３００　電動機
４００　着磁装置
４１０　コイル Reference Signs List 10 Rotor core 11 Through opening 12 Magnet insertion hole 12a Straight part (first part)
12b Convex part 12c First part 20 Magnet 20a Straight part (first part)
20b Convex part 20c First part 21 Split magnet 22 First magnet 22a Split magnet 23 Second magnet 30 Magnet material 31 Split magnet material 40 Insulating layer 50 Rotation shaft (output shaft)
60 d-axis magnetic flux path 61 q-axis magnetic flux path 100 rotor 200 stator 210 yoke part 220 tooth part 230 magnetic core 240 field coil 300 motor 400 magnetizing device 410 coil

Claims (8)

  1. 回転軸と、
    外周に沿った周方向に所定の間隔をあけて設けられた複数の磁石挿入孔を有する回転子鉄心と、
    前記複数の磁石挿入孔の各々に埋設された複数の磁石と、を含み、
    前記複数の磁石挿入孔の各々は、上面視で前記回転子鉄心の外周側から前記回転子鉄心の軸心側にかけて延びるように設けられ、かつ前記回転子鉄心の半径方向である径方向の長さが前記周方向の長さよりも長い第１部分を含み、
    前記複数の磁石の各々は、前記回転軸の延びる軸方向に積み重ねられて埋設された複数の分割磁石を含み、
    前記軸方向に隣り合う前記複数の分割磁石の間に絶縁層を含む回転子。     A rotation axis,
    A rotor core having a plurality of magnet insertion holes provided at predetermined intervals in a circumferential direction along the outer circumference,
    A plurality of magnets embedded in each of the plurality of magnet insertion holes,
    Each of the plurality of magnet insertion holes is provided so as to extend from an outer peripheral side of the rotor core to an axial side of the rotor core in a top view, and has a radial length that is a radial direction of the rotor core. Includes a first portion that is longer than the circumferential length,
    Each of the plurality of magnets includes a plurality of divided magnets stacked and buried in the axial direction in which the rotation axis extends,
    A rotor including an insulating layer between the plurality of divided magnets adjacent in the axial direction.
  2. 前記複数の磁石のうちの一つの磁石の外形は、上面視で前記複数の磁石挿入孔のうちの一つの磁石挿入孔の内周面に沿うように規定されている請求項１に記載の回転子。 The rotation according to claim 1, wherein an outer shape of one of the plurality of magnets is defined along an inner peripheral surface of one of the plurality of magnet insertion holes in a top view. Child.
  3. 前記複数の磁石の各々は、第１磁石と第２磁石とを含み、
    前記第１磁石は、前記第１部分に埋設され、前記回転子鉄心の軸心に近い側に位置し、かつ前記回転軸の延びる軸方向に積み重ねられた複数の分割磁石を含み、
    前記第２磁石は、前記回転子鉄心の外周に近い側に位置し、かつ前記第２磁石の側面の表面積は、前記第１磁石における１つの分割磁石の側面の表面積よりも大きく、更に前記第２磁石は、前記複数の磁石挿入孔内で絶縁層を挟んで前記第１磁石と前記回転子鉄心の半径方向である径方向で接する構成を含む、請求項１に記載の回転子。     Each of the plurality of magnets includes a first magnet and a second magnet,
    The first magnet includes a plurality of split magnets embedded in the first portion, located on a side closer to an axis of the rotor core, and stacked in an axial direction of the rotation shaft,
    The second magnet is located on a side closer to the outer periphery of the rotor core, and a surface area of a side surface of the second magnet is larger than a surface area of a side surface of one split magnet in the first magnet. 2. The rotor according to claim 1, wherein the two magnets include a configuration in which the two magnets are in contact with the first magnet in a radial direction that is a radial direction of the rotor core with an insulating layer interposed in the plurality of magnet insertion holes. 3.
  4. 前記第２磁石の前記軸方向の長さは前記複数の磁石挿入孔の前記軸方向の長さに実質的に等しい請求項３に記載の回転子。 4. The rotor according to claim 3, wherein the axial length of the second magnet is substantially equal to the axial length of the plurality of magnet insertion holes.
  5. 前記複数の磁石挿入孔は、上面視で前記回転子鉄心の軸心に向かって凸形状である請求項１に記載の回転子。 The rotor according to claim 1, wherein the plurality of magnet insertion holes are convex toward an axis of the rotor core in a top view.
  6. 前記磁石挿入孔は、上面視で前記回転子鉄心の外周側から前記回転子鉄心の軸心側に向かって延びる長方形状である請求項１に記載の回転子。 The rotor according to claim 1, wherein the magnet insertion hole has a rectangular shape extending from an outer peripheral side of the rotor core toward an axis side of the rotor core in a top view.
  7. 上面視で、前記複数の磁石のうち、前記周方向に隣り合う２つの磁石をそれぞれ通るｄ軸磁束通路と、前記複数の磁石の径方向外側に位置する前記回転子鉄心を通るｑ軸磁束通路とが形成され、磁気的突極性を有する請求項１に記載の回転子。 In top view, of the plurality of magnets, a d-axis magnetic flux path that passes through two circumferentially adjacent magnets, and a q-axis magnetic flux path that passes through the rotor core located radially outside the plurality of magnets. The rotor according to claim 1, wherein the rotor has magnetic saliency.
  8. 請求項１に記載の回転子と、
    前記回転子と所定の間隔をあけて配設された固定子と、を少なくとも備える電動機。     A rotor according to claim 1,
    An electric motor comprising at least the rotor and a stator disposed at a predetermined interval.
PCT/JP2019/034934 2018-09-20 2019-09-05 Rotor and electric motor using same WO2020059513A1 (en)

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JP2018-176340 2018-09-20

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007252077A (en) * 2006-03-15 2007-09-27 Nissan Motor Co Ltd Magnet structure
JP2010041842A (en) * 2008-08-06 2010-02-18 Toshiba Corp Permanent-magnet type rotary electric machine and permanent-magnet type motor drive system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007252077A (en) * 2006-03-15 2007-09-27 Nissan Motor Co Ltd Magnet structure
JP2010041842A (en) * 2008-08-06 2010-02-18 Toshiba Corp Permanent-magnet type rotary electric machine and permanent-magnet type motor drive system

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