Rotor, rotating electrical machine, rotor manufacturing method, and magnet

Abstract

The present invention provides a rotor, a rotating electrical machine, a method for manufacturing a rotor, and a magnet. The rotor of the present invention includes a rotor core and a magnet. The magnet is press-fitted into a magnet insertion hole provided in the rotor core. The magnet comprises a hard magnetic body and a resin layer. The resin layer is laminated on the hard magnetic body, is arranged radially outward of the rotor core, and contains a soft magnetic body. The resin layer has a groove extending in a direction intersecting the insertion direction.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2021-039642, filed on March 11, 2021, the contents of which are incorporated herein by reference. Technical Field

[0002] The present invention relates to a rotor, a rotating electrical machine, a method for manufacturing a rotor, and a magnet. Background Art

[0003] An interior permanent magnet type rotating electrical machine (so-called IPM motor, IPM: Interior Permanent Magnet) having a rotor core with permanent magnets embedded therein is known. Various technologies have been proposed for stably fixing permanent magnets in rotors used in interior permanent magnet type rotating electrical machines.

[0004] For example, Japanese Patent No. 5748911 discloses a method for fixing magnet insertion holes of a rotor core and permanent magnets with an adhesive, wherein iron powder as a soft magnetic material is mixed in the adhesive.

[0005] Japanese Patent Application Laid-Open No. 2015-089169 discloses a structure in which a permanent magnet having a coating layer made of a resin material provided on its surface is inserted into a magnet insertion hole of a rotor core heated to a temperature higher than the melting point of the resin material. Summary of the Invention

[0006] However, in the method described in Japanese Patent No. 5748911, when the adhesive is injected into the gap between the magnet insertion hole and the permanent magnet, the resin containing the iron powder may leak to both sides of the magnet, thereby reducing the torque density.

[0007] In the method described in Japanese Patent Application Laid-Open No. 2015-089169, a thermosetting and insulating epoxy resin or the like is used as a resin material to securely fix the permanent magnets to the rotor core. However, in order to achieve higher motor speeds, the resin layer may peel off, creating gaps between the permanent magnets and the magnet insertion holes.

[0008] The present invention provides a rotor, a rotating electrical machine, a method for manufacturing the rotor, and a magnet that utilizes magnets having excellent dimensional specifications to eliminate gaps between the magnets and magnet insertion holes, thereby improving performance such as torque and output.

[0009] [1] A rotor according to one embodiment of the present invention is characterized in that it comprises: a rotor core; and a magnet, which is pressed into a magnet insertion hole provided in the rotor core, the magnet having: a hard magnetic body; and a resin layer, which is stacked on the hard magnetic body, is arranged radially outside the rotor core, and includes a soft magnetic body, the resin layer having a groove extending in a direction intersecting the insertion direction.

[0010] [2] In the rotor according to one aspect of the present invention, the resin layer may include an inclined portion that is inclined so that the surface thereof widens from downstream toward upstream in the insertion direction.

[0011] [3] In the rotor according to one aspect of the present invention, the resin layer may contain a foaming agent.

[0012] [4] In the rotor according to one aspect of the present invention, the resin layer may be a semi-cured resin.

[0013] [5] In one embodiment of the rotor of the present invention, the magnet insertion hole may be provided in an arc shape protruding toward the central axis of the rotor core, and the magnet may be provided in an arc shape having the same arc center as that of the magnet insertion hole.

[0014] [6] Another embodiment of the present invention is a rotating electrical machine comprising: a rotor as described in any one of the above embodiments [1] to [5]; and a stator arranged radially outside the rotor with a gap therebetween.

[0015] [7] Another embodiment of the present invention is a method for manufacturing a rotor having a rotor core and a magnet, wherein the magnet is pressed into a magnet insertion hole provided in the rotor core, wherein the method for manufacturing the rotor is characterized in that the magnet has: a hard magnetic body; and a resin layer, which is stacked on the hard magnetic body, is arranged on the radially outer side of the rotor core, and includes a soft magnetic body, wherein the resin layer has a groove portion in a direction intersecting the insertion direction, and the method for manufacturing the rotor has a magnet insertion step, in which the magnet is pressed into the magnet insertion hole while the hard magnetic body is brought into contact with the radial inner side surface of the magnet insertion hole and at least a portion of the resin layer is brought into contact with the radial outer side surface of the magnet insertion hole.

[0016] [8] Another embodiment of the present invention is a method for manufacturing a rotor having a rotor core and a magnet, wherein the magnet is pressed into a magnet insertion hole provided in the rotor core, wherein the rotor manufacturing method is characterized in that the magnet has: a hard magnetic body; and a resin layer, which is stacked on the hard magnetic body, is arranged on the radially outer side of the rotor core, and contains a soft magnetic body, wherein the resin layer has a groove portion in a direction intersecting the insertion direction, and the rotor manufacturing method comprises: a magnet insertion hole heating step, in which at least the radially outer side surface of the magnet insertion hole among the circumference of the magnet insertion hole is heated to a predetermined temperature; and a magnet insertion step, in which, after the magnet insertion hole heating step, the magnet is pressed into the magnet insertion hole while the hard magnetic body is in contact with the radially inner side surface of the magnet insertion hole and at least a portion of the resin layer is in contact with the radially outer side surface of the magnet insertion hole.

[0017] [9] In another embodiment of the present invention, the rotor manufacturing method may include the resin layer containing a foaming agent, and the rotor manufacturing method may include a heating foaming step, in which the rotor core is heated after the magnet insertion step to foam the foaming agent.

[0018]

[10] In another embodiment of the present invention, the rotor manufacturing method may be such that the resin layer has an inclined portion that is inclined so that the surface widens from downstream toward upstream in the insertion direction, and in the magnet insertion step, the magnet is pressed into the magnet insertion hole from the inclined portion.

[0019]

[11] In another embodiment of the rotor manufacturing method of the present invention, the resin layer may be a semi-cured resin.

[0020]

[12] Another embodiment of the present invention is a magnet that is pressed into a magnet insertion hole provided in a rotor having a rotor core, and is characterized in that the magnet comprises: a hard magnetic body; and a resin layer that is stacked on the hard magnetic body, is arranged on the radially outer side of the rotor core, and includes a soft magnetic body, and the resin layer has a groove portion extending in a direction intersecting the insertion direction.

[0021] In the structure of the above-mentioned solution [1], the magnet is formed with a resin layer having grooves in a direction intersecting the insertion direction. Therefore, the magnet is pressed into the magnet insertion hole while the resin layer between the grooves is cut away. Therefore, the above-mentioned structure can easily press the magnet into the magnet insertion hole compared to a magnet having a resin layer without grooves in a direction intersecting the insertion direction. Moreover, since a resin layer containing a soft magnetic material is sandwiched between the hard magnetic material of the magnet and the magnet insertion hole, the resin does not leak to both sides of the magnet as in the case of injecting a resin containing an adhesive material, and the decrease in torque density can be suppressed.

[0022] According to the above structure, the magnet is pressed into the magnet insertion hole while the resin layer between the grooves is shaved off, and the remaining portion of the resin layer (shavings) enters the upstream groove, thereby suppressing wear. In addition, the remaining portion of the resin layer entering the upstream groove can suppress the generation of dust from the remaining portion of the resin layer.

[0023] In the structure of the above-mentioned scheme [2], the resin layer has an inclined portion in which the surface is inclined in a manner that widens from downstream toward upstream in the insertion direction. Therefore, the end portion on the downstream side of the magnet in the insertion direction can be easily guided into the magnet insertion hole, and the operation of pressing the magnet into the magnet insertion hole can be easily performed.

[0024] In the structure of the above-mentioned solution [3], the resin layer contains a foaming agent. Therefore, by foaming the foaming agent and expanding the resin layer, the gap between the hard magnetic body of the magnet and the magnet insertion hole can be reduced. In addition, by foaming the foaming agent and expanding the resin layer, the grooves and inclined portions formed in the resin layer can be filled.

[0025] In the structure of the above-mentioned solution [4], the resin layer is a semi-cured resin, so the magnet can be easily pressed into the magnet insertion hole compared to the case of using a resin with high hardness.

[0026] In the structure of the above-mentioned solution [5], the magnet insertion hole and the magnet are arranged in an arc shape. Therefore, the resin layer faces the radially outer circumferential surface of the magnet insertion hole. In other words, the resin layer is located on the inner side of the arc. Therefore, when the magnet is pressed into the magnet insertion hole, the remaining part of the resin layer enters the inner side of the arc, which can suppress the scattering of the remaining part of the resin layer (shavings).

[0027] In the structure of the above-mentioned solution [6], it is possible to provide a rotating electric machine having improved performance such as torque and output by having a rotor that eliminates the gap generated between the magnet and the magnet insertion hole by utilizing magnets with excellent dimensional system.

[0028] In the structure of the above-mentioned solution [7], during the magnet insertion process, the magnet is pressed in while the hard magnetic body is brought into contact with the radial inner side surface of the magnet insertion hole and at least a portion of the resin layer is brought into contact with the radial outer side surface of the magnet insertion hole. By having this magnet insertion process, the magnet can be pressed into the magnet insertion hole while the resin layer between the grooves is cut away. Moreover, according to the above-mentioned structure, since a resin layer containing a soft magnetic body is sandwiched between the hard magnetic body of the magnet and the magnet insertion hole, the resin will not leak to both sides of the magnet as in the case of injecting a resin containing an adhesive material, and the decrease in torque density can be suppressed.

[0029] According to the above configuration, the magnet is pressed into the magnet insertion hole while the resin layer between the grooves is shaved off. The remaining portion of the resin layer (shavings) enters the upstream groove, thereby suppressing wear. Furthermore, the remaining portion of the resin layer (shavings) entering the upstream groove suppresses dust generation from the remaining portion of the resin layer.

[0030] In the structure of the above-mentioned scheme [8], there is a magnet insertion process after the magnet insertion hole heating process. Through the magnet insertion hole heating process, the peripheral surface of the magnet insertion hole becomes high temperature. When the magnet is inserted into the high-temperature magnet insertion hole, the resin layer melts or softens. Specifically, a portion of the resin layer that cannot be inserted into the magnet insertion hole melts and falls off at the upstream end edge of the magnet insertion hole. Alternatively, a portion of the resin layer that cannot be inserted into the magnet insertion hole enters the upstream groove portion. Therefore, according to the above-mentioned structure, the resin layer can be manufactured without considering the thickness of the resin layer that fills the gap between the hard magnetic body of the magnet and the magnet insertion hole, and therefore, the manufacturing cost can be suppressed.

[0031] In the structure of the above-mentioned solution [9], a heating and foaming step is performed after the magnet insertion step in which the rotor core is heated to foam the foaming agent. By foaming the foaming agent and expanding the resin layer, the gap between the hard magnetic body of the magnet and the magnet insertion hole can be reduced. In addition, by foaming the foaming agent and expanding the resin layer, the grooves formed in the resin layer can be filled.

[0032] In the structure of the above-mentioned scheme

[10] , the resin layer has an inclined portion in which the surface is inclined in a manner that widens from downstream to upstream in the insertion direction. Therefore, the end portion on the downstream side of the magnet in the insertion direction can be easily guided into the magnet insertion hole, and the operation of pressing the magnet into the magnet insertion hole can be easily performed.

[0033] In the structure of the above-mentioned solution

[11] , the resin layer is a semi-cured resin, and therefore, compared with the case of using a resin with high hardness, it can be easily inserted into the magnet insertion hole.

[0034] In the structure of the above-mentioned scheme

[12] , the magnet is formed with a resin layer having grooves in a direction intersecting the insertion direction. Therefore, when the magnet is pressed into the magnet insertion hole provided in the rotor core, the resin layer between the grooves can be cut away while the magnet is pressed into the magnet insertion hole. Therefore, the above-mentioned structure can easily press the magnet into the magnet insertion hole compared to a magnet having a resin layer without grooves in a direction intersecting the insertion direction. Moreover, since a resin layer containing a soft magnetic material is sandwiched between the hard magnetic material of the magnet and the magnet insertion hole, the resin does not leak to both sides of the magnet as in the case of injecting a resin containing an adhesive material, and the decrease in torque density can be suppressed.

[0035] According to the above configuration, the magnet is pressed into the magnet insertion hole while the resin layer between the grooves is shaved off. Therefore, the remaining portion of the resin layer (shavings) enters the upstream groove, thereby suppressing wear. Furthermore, the remaining portion of the resin layer (shavings) entering the upstream groove suppresses dust generation from the remaining portion of the resin layer.

[0036] According to the aspects of the present invention, it is possible to provide a rotor, a rotating electrical machine, a method for manufacturing a rotor, and a magnet that eliminate gaps between the magnets and the magnet insertion holes using magnets having excellent dimensional specifications, thereby improving performance such as torque and output. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a cross-sectional view of a rotating electrical machine according to an embodiment of the present invention.

[0038] Figure 2 This is a front view of a rotor according to an embodiment of the present invention.

[0039] Figure 3 yes Figure 2 Enlarged view of Part III.

[0040] Figure 4 This is a perspective view of a magnet according to an embodiment of the present invention.

[0041] Figure 5 This is a flowchart showing a method for manufacturing a rotor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0042] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the embodiments, a rotating electric machine mounted on a vehicle such as a hybrid vehicle or an electric vehicle will be described.

[0043] Rotating electric machines

[0044] Figure 1 1 is a schematic structural diagram showing the overall structure of the rotating electrical machine 1 according to the embodiment. Figure 1The figure includes a cross section taken along a virtual plane including the axis C.

[0045] like Figure 1 As shown, the rotary electric machine 1 includes a case 2 , a stator 3 , a rotor 4 , and a shaft 5 .

[0046] The housing 2 is formed into a cylindrical box shape that accommodates the stator 3 and the rotor 4. A refrigerant (not shown) is contained within the housing 2. A portion of the stator 3 is immersed in the refrigerant within the housing 2. For example, ATF (Automatic Transmission Fluid), a hydraulic fluid used for lubrication of transmissions and power transmission, is used as the refrigerant.

[0047] The shaft 5 is rotatably supported by the housing 2. The shaft 5 is rotatably supported by the housing 2 via a bearing 6 mounted on the housing 2. Hereinafter, the direction along the axis C of the shaft 5 is referred to as the "axial direction," the direction orthogonal to the axis C is referred to as the "radial direction," and the direction around the axis C is referred to as the "circumferential direction."

[0048] The stator 3 includes a stator core 11 and a multilayer coil 12 mounted on the stator core 11 .

[0049] The stator core 11 is annular and coaxially arranged with the axis C. It is fixed to the inner circumference of the housing 2. For example, the stator core 11 is formed by stacking multiple electromagnetic steel sheets (silicon steel sheets) in the axial direction. It should be noted that the stator core 11 may also be a so-called powdered iron core, obtained by compressing and molding metal magnetic powder (soft magnetic powder).

[0050] The stator core 11 has slots 13 for inserting the coils 12. Multiple slots 13 are arranged at intervals in the circumferential direction. The coils 12 have insertion portions 12a that pass through the slots 13 of the stator core 11 and coil ends 12b that protrude axially from the stator core 11. The stator core 11 generates a magnetic field when current flows through the coils 12.

[0051] <Rotor>

[0052] The rotor 4 is arranged radially inwardly of the stator 3 at a distance therefrom. The rotor 4 is fixed to the shaft 5. The rotor 4 is configured to be rotatable around the axis C integrally with the shaft 5.

[0053] The rotor 4 includes a rotor core 21 , magnets 22 , and end plates 23 .

[0054] (Rotor core)

[0055] The rotor core 21 is annular and coaxially arranged with the axis C. The shaft 5 is press-fitted and fixed radially inside the rotor core 21. The rotor core 21 is formed by stacking multiple electromagnetic steel sheets (silicon steel sheets) in the axial direction. It should be noted that the rotor core 21 may also be a so-called powder core, obtained by compression-molding metal magnetic powder (soft magnetic powder).

[0056] The rotor core 21 includes a plurality of magnet insertion holes 25 extending through the rotor core 21 in the axial direction, an end rib 40 , a shaft through hole 45 , and a weight-reduced portion 46 .

[0057] The plurality of magnet insertion holes 25 are arranged at intervals in the circumferential direction on the outer periphery of the rotor core 21 .

[0058] Figure 2 The rotor 4 of the embodiment is viewed from the axial direction. Figure 1 II direction view. Figure 2 In the figure, the shaft 5, the end plate 23, etc. are omitted. Figure 3 yes Figure 2 Enlarged view of Part III.

[0059] The plurality of magnet insertion holes 25 include a first magnet insertion hole 31, a second magnet insertion hole 32, and a third magnet insertion hole 33. Figure 2 As shown, in this embodiment, eight magnet insertion holes 25 are provided.

[0060] The first magnet insertion hole 31 is provided in an arc shape that is convex toward the central axis of the rotor core 21 when viewed from the axial direction. Figure 3 As shown, both ends of the first magnet insertion hole 31 are located radially inward of the outer circumferential surface of the rotor core 21. A first end portion 31A is provided radially outward of the first magnet insertion hole 31. The first end portion 31A smoothly connects the radially outer outer circumferential surface of the first magnet insertion hole 31 with the radially inner inner circumferential surface of the first magnet insertion hole 31.

[0061] A first protrusion 31D is provided between the first end portion 31A and the radially inner inner peripheral surface of the first magnet insertion hole 31 .

[0062] The second magnet insertion holes 32 are positioned radially inward of the first magnet insertion holes 31. A pair of second magnet insertion holes 32 are circumferentially arranged side by side, sandwiching a radially extending first center rib 32C. When viewed axially, the pair of second magnet insertion holes 32 are formed into an arc shape having the same curvature and arc center as the first magnet insertion holes 31.

[0063] A second outer end portion 32A is provided radially outward of the end portion of the second magnet insertion hole 32. A second inner end portion 32B is provided radially inward of the end portion of the second magnet insertion hole 32. A first center rib 32C is provided circumferentially inward of the pair of second inner end portions 32B. The second outer end portion 32A and the second inner end portion 32B smoothly connect the radially outer outer circumferential surface of the second magnet insertion hole 32 with the radially inner inner circumferential surface of the second magnet insertion hole 32.

[0064] A second protrusion 32D is provided between the second outer end portion 32A and the radially inner inner peripheral surface of the second magnet insertion hole 32 .

[0065] The third magnet insertion holes 33 are located radially inward of the second magnet insertion holes 32. A pair of third magnet insertion holes 33 are circumferentially arranged side by side, sandwiching a radially extending second center rib 33C. When viewed axially, the pair of third magnet insertion holes 33 are formed into an arc shape having the same curvature and arc center as the first magnet insertion holes 31 and the second magnet insertion holes 32.

[0066] A third outer end portion 33A is provided radially outward of the end portion of the third magnet insertion hole 33. A third inner end portion 33B is provided radially inward of the end portion of the third magnet insertion hole 33. A second center rib 33C is provided circumferentially inward of the pair of third inner end portions 33B. The third outer end portion 33A and the third inner end portion 33B smoothly connect the radially outer outer circumferential surface of the third magnet insertion hole 33 with the radially inner inner circumferential surface of the third magnet insertion hole 33.

[0067] A third protrusion 33D is provided between the third outer end portion 33A and the radially inner inner peripheral surface of the third magnet insertion hole 33 .

[0068] The end ribs 40 are provided radially outward of the first end portion 31A, the second outer end portion 32A, and the third outer end portion 33A, which are located radially outward of the magnet insertion hole 25. The end ribs 40 include a first end rib 41, a second end rib 42, and a third end rib 43. When viewed in the axial direction, the first end rib 41, the second end rib 42, and the third end rib 43 are each provided with the same thickness in the radial direction.

[0069] The first end rib 41 is provided between the outer circumferential surface of the rotor core 21 and the first end 31A of the first magnet insertion hole 31. The second end rib 42 is provided between the outer circumferential surface of the rotor core 21 and the second outer end 32A of the second magnet insertion hole 32. The third end rib 43 is provided between the outer circumferential surface of the rotor core 21 and the third outer end 33A of the third magnet insertion hole 33.

[0070] like Figure 2As shown, the shaft through hole 45 is provided at a position radially inward of the magnet insertion hole 25. The shaft through hole 45 passes through the rotor core 21 in the axial direction. The shaft through hole 45 is provided coaxially with the axis C. The shaft through hole 45 is inserted into the shaft 5 (refer to FIG. Figure 1 The shaft 5 is, for example, press-fitted into and fixed to the shaft through-hole 45 .

[0071] like Figure 2 As shown, the weight-reducing portion 46 is provided radially between the magnet insertion hole 25 and the shaft through-hole 45. The weight-reducing portion 46 axially penetrates the rotor core 21. The weight-reducing portion 46 is provided between circumferentially adjacent magnet insertion holes 25. When viewed axially, the weight-reducing portion 46 is formed into a triangular shape with a top on the radially outer side. The interior of the weight-reducing portion 46 is formed to allow, for example, a screw member (not shown) to pass through.

[0072] Providing the weight-reduced portion 46 can reduce the weight of the rotor core 21. The weight-reduced portion 46 functions as a magnetic flux barrier.

[0073] (End version)

[0074] The end plates 23 are disposed at both axial ends of the rotor core 21. The end plates 23 only need to cover at least the plurality of magnet insertion holes 25. The end plates 23 abut against the axial outer end surfaces of the rotor core 21. The end plates 23 are press-fitted and fixed to the shaft 5.

[0075] <Magnet>

[0076] Figure 4 It is a perspective view of the magnet 22 .

[0077] The magnet 22 is press-fitted into the magnet insertion hole 25. The magnet 22 includes a hard magnetic body 51 and a resin layer 52 laminated on the hard magnetic body 51.

[0078] The magnet 22 is formed in an arc shape having the same curvature and arc center as those of the first magnet insertion hole 31 , the second magnet insertion hole 32 , and the third magnet insertion hole 33 .

[0079] In the following description of the magnet 22, the downstream side in the insertion direction when the magnet 22 is inserted (pressed) into the magnet insertion hole 25 is sometimes referred to as the "first side", and the upstream side in the insertion direction when the magnet 22 is inserted (pressed) into the magnet insertion hole 25 is sometimes referred to as the "second side".

[0080] The hard magnetic body 51 is formed of a permanent magnet. It is located radially inward of the magnet insertion hole 25. Of the hard magnetic body 51 and the resin layer 52 included in the magnet 22, at least the hard magnetic body 51 may be formed into an arc shape having the same curvature and arc center as the first magnet insertion hole 31, the second magnet insertion hole 32, and the third magnet insertion hole 33. The circumferentially outer ends of the hard magnetic body 51 are in contact with the first protrusion 31D, the second protrusion 32D, and the third protrusion 33D.

[0081] Resin layer 52 faces the radially outer peripheral surface of arc-shaped magnet insertion hole 25 when magnet 22 is press-fitted into magnet insertion hole 25. In this embodiment, resin layer 52 is located inside the arc of magnet insertion hole 25.

[0082] The resin layer 52 has a groove portion 53 extending in a direction intersecting the direction of insertion into the magnet insertion hole 25. In the present embodiment, the groove portion 53 is set in a straight line. The groove portion 53 can extend in a direction intersecting the insertion direction, or it can be set in a spiral shape. The groove portion 53 makes the surface of the resin layer 52 facing the hard magnetic body 51 concave in a U shape. The depth of the concave portion 53 gradually deepens from the first side of the magnet 22 toward the second side. The groove portion 53 can be formed by scraping off the surface of the resin layer 52, or by providing concave and convex portions on the mold to form the groove portion 53 simultaneously with the forming of the resin layer 52.

[0083] The resin layer 52 has an inclined portion 54 whose surface widens from downstream toward upstream in the insertion direction. The inclined portion 54 only needs to be provided on the first side of the magnet 22. The groove 53 in the resin layer 52 where the inclined portion 54 is provided is cut away. The inclined portion 54 can be formed by cutting away the surface of the resin layer 52, or by providing a recessed and raised portion in the mold simultaneously with the molding of the resin layer 52. The order in which the groove 53 and the inclined portion 54 are formed is not important.

[0084] The resin layer 52 is formed of a semi-cured resin. The semi-cured resin is preferably a thermoplastic resin or a thermosetting resin, and more preferably a thermoplastic resin. In this embodiment, a thermoplastic epoxy resin or the like can be used as the semi-cured resin.

[0085] The resin layer 52 contains a foaming agent in the semi-cured resin. The foaming agent may have a composition that foams when heated.

[0086] <Rotor Manufacturing Method>

[0087] Next, a method for manufacturing the above-mentioned rotor 4 will be described. Figure 5 1 is a flowchart illustrating a method for manufacturing the rotor 4 .

[0088] like Figure 5As shown, the method for manufacturing the rotor 4 includes a magnet insertion hole heating step S1 , a magnet inserting step S2 , and a heating and foaming step S3 .

[0089] The magnet insertion hole heating step S1 is a step of heating at least the radially outer peripheral surface of the magnet insertion hole 25 to a predetermined temperature. In this embodiment, the predetermined temperature may be a temperature at which the resin layer 52 softens or melts.

[0090] The magnet insertion step S2 is performed after the magnet insertion hole heating step S1. In the magnet insertion step S2, the magnet 22 is press-fitted into the magnet insertion hole 25 while the hard magnetic body 51 contacts the radially inner side of the magnet insertion hole 25 and at least a portion of the resin layer 52 contacts the radially outer side of the magnet insertion hole 25. In this embodiment, the magnet 22 is inserted into the magnet insertion hole 25 from the first side of the resin layer 52, where the inclined portion 54 is provided.

[0091] The heating and foaming step S3 is performed after the magnet insertion step S2. In the heating and foaming step S3, the rotor core 21 is heated to foam the foaming agent contained in the resin layer 52. In the heating and foaming step S3, the magnets 22 may be heated instead of the rotor core 21 to foam the foaming agent contained in the resin layer 52. The amount of foaming agent contained is not particularly limited; however, the amount of foaming agent may be sufficient to fill the gaps between the grooves 53 and the inclined portions 54 and the magnet insertion holes 25.

[0092] In this embodiment, the rotor 4 manufacturing method is described as including a magnet insertion hole heating step S1, a magnet insertion step S2, and a heating and foaming step S3, but the present invention is not limited thereto. The rotor 4 manufacturing method only needs to include the magnet insertion step S2. In this case, the magnets 22 are press-fitted into the magnet insertion holes 25 while the resin layer 52 between the grooves 53 is trimmed.

[0093] The method for manufacturing the rotor 4 may include the magnet insertion hole heating step S1 and the magnet inserting step S2 in sequence, or the magnet inserting step S2 and the heating and foaming step S3 in sequence.

[0094] (Effect)

[0095] In the above embodiment, magnet 22 is formed with resin layer 52 having grooves 53 extending in a direction intersecting the insertion direction. Therefore, when press-fitting magnet 22 into magnet insertion hole 25 provided in rotor core 21, resin layer 52 between grooves 53 can be removed while being pressed into magnet insertion hole 25. Therefore, according to the above embodiment, magnet 22 can be press-fitted into magnet insertion hole 25 more easily than magnet 22 having resin layer 52 without grooves 53 extending in a direction intersecting the insertion direction. Furthermore, since resin layer 52 containing a soft magnetic material is sandwiched between the hard magnetic material 51 of magnet 22 and magnet insertion hole 25, resin leakage to both sides of magnet 22, as occurs when injecting resin containing an adhesive, can be avoided, thereby suppressing a decrease in torque density.

[0096] According to the above embodiment, the magnet 22 is press-fitted into the magnet insertion hole 25 while the resin layer 52 between the grooves 53 is shaved off. The remaining portion of the resin layer 52 (shavings) enters the upstream groove 53, thereby suppressing wear. Furthermore, the remaining portion of the resin layer 52 entering the upstream groove 53 can suppress the generation of dust from the remaining portion of the resin layer 52.

[0097] In the above embodiment, the resin layer 52 has an inclined portion 54 in which the surface is inclined in a manner that widens from downstream to upstream in the insertion direction. Therefore, the end portion on the downstream side of the insertion direction of the magnet 22 can be easily guided into the magnet insertion hole 25, and the operation of pressing the magnet 22 into the magnet insertion hole 25 can be easily performed.

[0098] In the above embodiment, the resin layer 52 contains a foaming agent. Therefore, by foaming the foaming agent and expanding the resin layer 52, the gap between the hard magnetic body 51 of the magnet 22 and the magnet insertion hole 25 can be reduced. In addition, by foaming the foaming agent and expanding the resin layer 52, the groove 53 formed in the resin layer 52 can be filled.

[0099] In the above embodiment, the resin layer 52 is a semi-cured resin. Therefore, the magnet 22 can be easily pressed into the magnet insertion hole 25 compared to the case where a resin with high hardness is used.

[0100] In the above embodiment, the magnet insertion hole 25 and the magnet 22 are formed in an arc shape. Therefore, the resin layer 52 faces the radially outer circumference of the magnet insertion hole 25. Specifically, because the resin layer 52 is located inside the arc, when the magnet 22 is press-fitted into the magnet insertion hole 25, the remaining portion of the resin layer 52 enters the inner portion of the arc, thereby preventing the remaining portion of the resin layer 52 (shavings) from scattering.

[0101] In the above embodiment, in the magnet insertion step S2, the magnet 22 is press-fitted while the hard magnetic body 51 is in contact with the radially inner side surface of the magnet insertion hole 25 and at least a portion of the resin layer 52 is in contact with the radially outer side surface of the magnet insertion hole 25. This magnet insertion step S2 allows the magnet 22 to be press-fitted into the magnet insertion hole 25 while the resin layer 52 between the grooves 53 is trimmed. Furthermore, according to the above embodiment, the resin layer 52 containing a soft magnetic material is interposed between the hard magnetic body 51 of the magnet 22 and the magnet insertion hole 25. This prevents leakage of resin to both sides of the magnet 22, as occurs when a resin containing an adhesive is injected, thereby suppressing a decrease in torque density.

[0102] According to the above embodiment, the magnet 22 is press-fitted into the magnet insertion hole 25 while the resin layer 52 between the grooves 53 is shaved off. The remaining portion of the resin layer 52 (shavings) enters the upstream groove 53, thereby suppressing wear. Furthermore, the remaining portion of the resin layer 52 (shavings) entering the upstream groove 53 can suppress the generation of dust from the remaining portion of the resin layer 52.

[0103] In the above embodiment, the magnet insertion hole heating step S2 is performed after the magnet insertion hole heating step S1. Through the magnet insertion hole heating step S1, the peripheral surface of the magnet insertion hole 25 becomes high temperature. When the magnet 22 is inserted into the high-temperature magnet insertion hole 25, the resin layer 52 melts or softens. A portion of the resin layer 52 that cannot be inserted into the magnet insertion hole 25 melts and falls off at the upstream end edge of the magnet insertion hole 25. Alternatively, a portion of the resin layer 52 that cannot be inserted into the magnet insertion hole 25 enters the upstream groove portion 53. Therefore, according to the above embodiment, the resin layer 52 can be manufactured without considering the thickness of the resin layer 52 that fills the gap between the hard magnetic body 51 of the magnet 22 and the magnet insertion hole 25, and therefore, the manufacturing cost can be suppressed.

[0104] In the above embodiment, after the magnet insertion step S2, a heating and foaming step S3 is performed in which the rotor core 21 is heated to foam the foaming agent. By foaming the foaming agent and expanding the resin layer 52, the gap between the hard magnetic body 51 of the magnet 22 and the magnet insertion hole 25 can be reduced. Furthermore, by expanding the resin layer 52 through foaming of the foaming agent, the groove 53 and the inclined portion 54 formed in the resin layer 52 can be filled.

[0105] In the above embodiment, the resin layer 52 has an inclined portion 54 in which the surface is inclined in a manner that widens from downstream to upstream in the insertion direction. Therefore, the end portion on the downstream side (first side) in the insertion direction of the magnet 22 can be easily guided into the magnet insertion hole 25, and the operation of pressing the magnet 22 into the magnet insertion hole 25 can be easily performed.

[0106] In the above embodiment, the resin layer 52 is a semi-cured resin, and therefore, can be inserted into the magnet insertion hole 25 more easily than when a resin having high hardness is used.

[0107] As described above, according to this embodiment, it is possible to provide a rotor 4, a rotating electrical machine 1, a method for manufacturing the rotor 4, and a magnet 22 that eliminates the gap between the magnet 22 and the magnet insertion hole 25 by utilizing the magnet 22 having an excellent dimensional system, and to improve the performance of the rotating electrical machine 1 such as torque and output.

[0108] While preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and additions, omissions, substitutions, and other modifications may be made without departing from the spirit of the present invention. The above-described modifications may also be appropriately combined.

Claims

1. A rotor, characterized in that: The rotor comprises: a rotor core; and a magnet that is press-fitted into a magnet insertion hole provided in the rotor core; The magnet has: hard magnetic bodies; and a resin layer, which is laminated on the hard magnetic body, is arranged radially outside the rotor core, and contains a soft magnetic body; The resin layer has a groove extending in a direction intersecting the insertion direction, The recessed depth of the groove portion gradually increases from downstream toward upstream in the insertion direction of the magnet.

2. The rotor according to claim 1, wherein The resin layer has an inclined portion that is inclined so that a surface thereof widens from downstream toward upstream in the insertion direction.

3. The rotor according to claim 1 or 2, wherein: The resin layer contains a foaming agent.

4. The rotor according to claim 1 or 2, wherein: The resin layer is a semi-cured resin.

5. The rotor according to claim 1 or 2, wherein: The magnet insertion hole is provided in an arc shape convex toward the central axis of the rotor core. The magnet is provided in an arc shape having an arc center that is the same as that of the magnet insertion hole.

6. A rotating electrical machine, characterized in that: The rotating electrical machine comprises: The rotor according to any one of claims 1 to 5; and The stator is arranged radially outside the rotor with a gap therebetween.

7. A method for manufacturing a rotor, characterized in that: The rotor includes a rotor core and a magnet, wherein the magnet is press-fitted into a magnet insertion hole provided in the rotor core. The magnet has: Hard magnetic bodies; as well as a resin layer, which is laminated on the hard magnetic body, is arranged radially outside the rotor core, and contains a soft magnetic body; The resin layer has a groove portion in a direction intersecting the insertion direction, The rotor manufacturing method includes a magnet inserting step in which the magnet is press-fitted into the magnet insertion hole while the hard magnetic body is in contact with the radially inner side surface of the magnet insertion hole and at least a portion of the resin layer is in contact with the radially outer side surface of the magnet insertion hole. The recessed depth of the groove portion gradually increases from downstream toward upstream in the insertion direction of the magnet.

8. A method for manufacturing a rotor, characterized in that: The rotor includes a rotor core and a magnet, wherein the magnet is press-fitted into a magnet insertion hole provided in the rotor core. The magnet has: Hard magnetic bodies; as well as a resin layer, which is laminated on the hard magnetic body, is arranged radially outside the rotor core, and contains a soft magnetic body; The resin layer has a groove portion in a direction intersecting the insertion direction, The manufacturing method of the rotor comprises: a magnet insertion hole heating step of heating at least a radially outer side surface of the magnet insertion hole among the peripheral surfaces of the magnet insertion hole to a predetermined temperature; and a magnet insertion step, after the magnet insertion hole heating step, pressing the magnet into the magnet insertion hole while bringing the hard magnetic body into contact with the radial inner side surface of the magnet insertion hole and bringing at least a portion of the resin layer into contact with the radial outer side surface of the magnet insertion hole; The recessed depth of the groove portion gradually increases from downstream toward upstream in the insertion direction of the magnet.

9. The method for manufacturing a rotor according to claim 8, wherein: The resin layer contains a foaming agent, The rotor manufacturing method includes a heating and foaming step of heating the rotor core to foam the foaming agent after the magnet inserting step.

10. The method for manufacturing a rotor according to claim 7 or 8, wherein: The resin layer has an inclined portion that is inclined so that its surface widens from downstream toward upstream in the insertion direction. In the magnet insertion process, The magnet is press-fitted into the magnet insertion hole from the inclined portion.

11. The method for manufacturing a rotor according to claim 7 or 8, wherein: The resin layer is a semi-cured resin.

12. A magnet, in a rotor having a rotor core, which is press-fitted into a magnet insertion hole provided in the rotor core, characterized in that: The magnet has: Hard magnetic bodies; as well as a resin layer, which is laminated on the hard magnetic body, is arranged radially outside the rotor core, and contains a soft magnetic body; The resin layer has a groove extending in a direction intersecting the insertion direction, The recessed depth of the groove portion gradually increases from downstream toward upstream in the insertion direction of the magnet.

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