Rotor and rotating electric machine

Abstract

The present application provides a rotor and a rotary electric machine. The rotor of the present application is characterized by comprising: a rotor core that is formed with a shaft through-hole and a plurality of magnet insertion holes that are formed in a radial direction toward a central axis of the shaft through-hole; and magnets that are press-fitted into the magnet insertion holes, the rotor core having a reinforcement unit between the shaft through-hole and a first magnet insertion hole that is located at an outermost side in the radial direction.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2021-040709 filed on March 12, 2021, and incorporates the contents thereof herein. Technical Field

[0002] The present invention relates to a rotor and a rotating electric machine. Background Art

[0003] An interior permanent magnet (IPM) motor is known for its rotor core, which has a permanent magnet embedded within it. To achieve higher rotational speeds, various proposed rotor structures employ magnet insertion holes formed in multiple radial layers in the rotor core and for inserting magnets into these holes.

[0004] For example, Japanese Patent No. 6319973 discloses a structure in which a plurality of magnet embedding holes include outer peripheral magnet embedding holes located on the outer peripheral side of a rotor core (rotor core) and inner peripheral magnet embedding holes located on the central side of a rotor core. Summary of the Invention

[0005] In a structure where magnet insertion holes are formed in multiple radial layers in the rotor core and magnets are inserted into these holes, the rotor becomes heavier because the magnets are inserted radially inward of the rotor core. As the rotor becomes heavier, the centrifugal force acting on the rotor increases, so it is desirable to increase the rotor's strength.

[0006] An object of the present invention is to provide a rotor and a rotating electrical machine that can improve strength and can be used stably even at high rotation speeds.

[0007] [1] A rotor according to one embodiment of the present invention is characterized in that it comprises: a rotor core having a shaft through hole and a magnet insertion hole, wherein the magnet insertion hole is formed in multiple layers along a radial direction toward a central axis of the shaft through hole; and a magnet pressed into the magnet insertion hole, wherein the rotor core comprises a reinforcement unit between the shaft through hole and a first magnet insertion hole located on the outermost side in the radial direction.

[0008] [2] In the rotor described in [1] above, the rotor core may include a weight-reducing portion extending through the rotor core in the axial direction, and the reinforcing unit may be disposed inside the weight-reducing portion.

[0009] [3] In the rotor described in [2] above, the rotor core may include end panels at both ends in the axial direction, and the reinforcement unit may include a member that passes through the weight-reducing portion and is fixed to the end panels.

[0010] [4] In the rotor described in [1] above, the reinforcing unit can include a resin material.

[0011] [5] In the rotor described in [1] above, a second magnet insertion hole, which is located on an inner side of the radial direction than the first magnet insertion hole, of the plurality of magnet insertion holes is arranged in a pair in the circumferential direction with a central rib extending in the radial direction interposed therebetween, and the reinforcing unit includes the central rib.

[0012] [6] In the rotor of any one of [1] to [5] above, a compression unit can be provided which applies a load to the rotor core from an outer side of the radial direction toward an inner side of the radial direction.

[0013] [7] In the rotor described in [5] above, a compression unit can be provided which applies a load to the rotor core from an outer side of the radial direction toward an inner side of the radial direction, and the reinforcing unit includes a contact portion which contacts the magnet when the load is applied to the rotor core by the compression unit.

[0014] [8] In the rotor described in [7] above, the rotor core has a protrusion on a circumferential surface on an inner side of the radial direction of the magnet insertion hole which protrudes toward an outer side of the radial direction, the protrusion contacts one end portion of the magnet pressed into the second magnet insertion hole, and the contact portion contacts another end portion of the magnet pressed into the second magnet insertion hole.

[0015] [9] In the rotor described in [8] above, the other end portion of the magnet is provided separately from the central rib.

[0016]

[10] In the rotor of any one of [1] to [9] above, the magnet insertion hole is provided in a circular arc shape which protrudes toward a center axis of the rotor core, and the magnet is provided in a circular arc shape.

[0017]

[11] Another aspect of the present application is a rotary electric machine characterized by comprising: the rotor described in any one of [1] to

[10] above; and a stator disposed apart from the rotor by a gap on an outer side of the radial direction.

[0018] In the structure described in [1] above, the reinforcing unit is provided by the rotor core, and the strength of the rotor can be improved.

[0019] Therefore, according to the above structure, a rotor 4 which can improve the strength and can be stably used at high rotation can be provided.

[0020] In the structure described in [2] above, by providing a weight-reducing portion in the rotor core, the rotor core can be made lighter, and can be used stably even at high rotation speeds. In addition, by arranging a reinforcing unit in the weight-reducing portion, the strength of the rotor core can be increased.

[0021] In the structure described in [3] above, the reinforcing unit is fixed by axially clamping the end plates at both ends of the rotor core. Therefore, the strength of the rotor core can be improved without affecting the magnetic field.

[0022] In the structure described in [4] above, the resin material is contained in the reinforcing unit. Since the resin material can be easily filled into the magnet insertion hole and the interior of the weight-reducing portion, the rotor can be easily reinforced.

[0023] In the structure described in [5] above, the central rib is included in the reinforcing unit. The central rib can improve the strength of the rotor core and support the magnets, thereby facilitating high rotation speed of the rotor.

[0024] In the structure described in [6] above, a compression unit is provided for applying a load to the rotor core from the radially outer side toward the radially inner side. The strength of the rotor core is ensured by the reinforcement unit, and the rotor core is compressed by the compression unit, thereby achieving high rotation speed of the rotor.

[0025] In the structure described in [7] above, the reinforcing unit includes a contact portion that contacts the magnet when a load is applied to the rotor core by the compression unit. This makes it easier to insert the magnet into the magnet insertion hole than in a case where a magnet insertion hole is pre-set to reduce the gap with the magnet. Furthermore, the compression unit generates compression deformation between the rotor core and the contact portion, thereby securing the magnet and achieving high rotor rotation speed.

[0026] In the structure described in [8] above, the protrusion contacts one end of the magnet pressed into the second magnet insertion hole. By making the protrusion contact one end of the magnet, a gap can be provided between the outer peripheral surface of the second magnet insertion hole and the one end of the magnet, thereby reducing the leakage magnetic field.

[0027] In the structure described in [9] above, the other end of the magnet is separated from the central rib. That is, a gap is provided between the other end of the magnet and the central rib. Since the gap functions as a flux barrier, it is possible to improve the performance of the rotor.

[0028] In the structure described in

[10] , the arc-shaped magnets can reduce the circumferential thickness of the central ribs relative to the case of linear magnets. In addition, the use of arc-shaped magnets has the advantage that the magnets will not be crushed by centrifugal force.

[0029] In the structure described in the above-mentioned

[11] , the rotor core of the rotating electrical machine is provided with a reinforcing unit, thereby increasing the strength of the rotor.

[0030] Therefore, according to the above configuration, it is possible to provide a rotating electrical machine that can improve strength and can be used stably even at high rotation speeds.

[0031] As described above, according to one aspect of the present invention, it is possible to provide a rotor and a rotating electrical machine that can improve strength and can be used stably even at high rotation speeds. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a cross-sectional view of a rotating electrical machine according to an embodiment of the present invention.

[0033] Figure 2 This is a front view of a rotor according to an embodiment of the present invention.

[0034] Figure 3 yes Figure 2 Enlarged view of Part III.

[0035] Figure 4 yes Figure 2 IV-IV sectional view of FIG. DETAILED DESCRIPTION

[0036] 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.

[0037] Rotating electric machines

[0038] Figure 1 1 is a schematic structural diagram showing the overall structure of the rotating electrical machine 1 according to the embodiment. Figure 1 The figure includes a cross section taken along a virtual plane including the axis C.

[0039] like Figure 1 As shown, the rotary electric machine 1 includes a case 2 , a stator 3 , a rotor 4 , and a shaft 5 .

[0040] 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 transmission lubrication and power transmission, is used as the refrigerant.

[0041] 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."

[0042] The stator 3 includes a stator core 11 and a multilayer coil 12 mounted on the stator core 11 .

[0043] 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 dust core, obtained by compression-molding metal magnetic powder (soft magnetic powder).

[0044] 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 are inserted into 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 by flowing current through the coils 12.

[0045] <Rotor>

[0046] 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.

[0047] The rotor 4 includes a rotor core 21 , magnets 22 , end plates 23 , and an annular member 8 .

[0048] <Rotor core>

[0049] 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 dust core, obtained by compression-molding metal magnetic powder (soft magnetic powder).

[0050] The rotor core 21 includes a plurality of magnet insertion holes 25 that penetrate the rotor core 21 in the axial direction, end ribs 40 , shaft through holes 45 , weight-reducing portions 46 , and reinforcement means.

[0051] The plurality of magnet insertion holes 25 are arranged at intervals in the circumferential direction on the outer periphery of the rotor core 21 .

[0052] 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 illustration of the shaft 5 and the end plate 23 and the like is omitted. Figure 3 Figure 2 is an enlarged view of the III portion of Figure 4 Figure 2 is a IV-IV sectional view of

[0053] The plurality of magnet insertion holes 25 have a first magnet insertion hole 31 located at the radially outermost side, and a second magnet insertion hole 35 located at a radially inner side than the first magnet insertion hole 31. The second magnet insertion hole 35 has an outer side second magnet insertion hole 32 and an inner side second magnet insertion hole 33. As Figure 2 indicated, in the present embodiment, the magnet insertion hole 25 is provided with eight poles.

[0054] The first magnet insertion hole 31 is provided in a circular arc shape that protrudes toward the center axis of the rotor core 21 when viewed from the axial direction. As Figure 3 indicated, both end portions of the first magnet insertion hole 31 are located at positions that are radially inner than the outer peripheral surface of the rotor core 21. An outer side first end portion 31A is provided at a radially outer side of the first magnet insertion hole 31. The outer side first end portion 31A smoothly connects the outer peripheral surface at the radially outer side of the first magnet insertion hole 31 and the inner peripheral surface at the radially inner side of the first magnet insertion hole 31.

[0055] A first protrusion 31D is provided between the outer side first end portion 31A and the inner peripheral surface at the radially inner side of the first magnet insertion hole 31. Hereinafter, as Figure 3 indicated, an imaginary line that links the inner side end portion in the circumferential direction of a pair of first protrusions 31D and the center axis of the rotor core 21 is referred to as an imaginary line V5.

[0056] The outer side second magnet insertion hole 32 is provided at a position that is radially inner than the first magnet insertion hole 31. The outer side second magnet insertion hole 32 is arranged in a pair across the first central rib 32C that extends in the radial direction. The pair of outer side second magnet insertion holes 32 are formed in a circular arc shape having the same curvature and circular arc center as the first magnet insertion hole 31 when viewed from the axial direction.

[0057] A second outer end portion 32A is provided at a radially outer side one end portion of the end portions of the outer side second magnet insertion hole 32. A second inner end portion 32B is provided at a radially inner side other end portion of the end portions of the outer side second magnet insertion hole 32. The first central rib 32C is provided at a circumferential inner side of the pair of second inner end portions 32B. Specifically, the first central rib 32C is provided between an imaginary line V1 that links the outer peripheral surfaces at the radially outer sides of the pair of outer side second magnet insertion holes 32 and an imaginary line V2 that links the inner peripheral surfaces at the radially inner sides of the pair of outer side second magnet insertion holes 32.

[0058] ​​A second protrusion 32D is provided between the second outer end portion 32A and the radially inner inner peripheral surface of the outer second magnet insertion hole 32 .

[0059] A first contact portion 32E is provided between the radially outer end of the second inner end portion 32B on the radially outer peripheral surface of the outer second magnet insertion hole 32 and a first intersection point V51 with the imaginary line V5. In this embodiment, the radially outer peripheral surface of the outer second magnet insertion hole 32 is formed into a smooth arc shape, but the structure is not limited to this. Alternatively, the first contact portion 32E on the radially outer peripheral surface of the outer second magnet insertion hole 32 may protrude radially inward toward the center axis C.

[0060] The second outer end portion 32A and the second inner end portion 32B smoothly connect the radially outer outer circumferential surface of the outer second magnet insertion hole 32 with the radially inner inner circumferential surface of the outer second magnet insertion hole 32. Specifically, the pair of second inner end portions 32B protrude circumferentially toward each other. Therefore, the circumferential thickness of the first center rib 32C is thickest at the imaginary lines V1 and V2, and gradually decreases as it moves radially inward from the imaginary line V1. Furthermore, the circumferential thickness of the first center rib 32C gradually decreases as it moves radially outward from the imaginary line V2. That is, the circumferential thickness of the first center rib 32C is thinnest at the radially central portion between the imaginary lines V1 and V2. In other words, the circumferential distance between the pair of second inner end portions 32B is smallest at the radially central portion between the imaginary lines V1 and V2.

[0061] The inner second magnet insertion holes 33 are positioned radially inward of the outer second magnet insertion holes 32. A pair of inner second magnet insertion holes 33 are circumferentially arranged with a radially extending second center rib 33C interposed therebetween. When viewed axially, the pair of inner second 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 outer second magnet insertion holes 32.

[0062] A third outer end portion 33A is provided at one radially outer end of the inner second magnet insertion hole 33. A third inner end portion 33B is provided at the other radially inner end of the inner second magnet insertion hole 33. A second central rib 33C is provided circumferentially inward of the pair of third inner end portions 33B. Specifically, the second central rib 33C is provided between an imaginary line V3 connecting the radially outer outer circumferential surfaces of the pair of inner second magnet insertion holes 33 and an imaginary line V4 connecting the radially inner inner circumferential surfaces of the pair of inner second magnet insertion holes 33.

[0063] A third protrusion 33D is provided between the third outer end portion 33A and the radially inner inner peripheral surface of the inner second magnet insertion hole 33 .

[0064] A second contact portion 33E is provided between the radially outer end of the third inner end portion 33B on the radially outer peripheral surface of the inner second magnet insertion hole 33 and a second intersection point V52 with the imaginary line V5. In this embodiment, the radially outer peripheral surface of the inner second magnet insertion hole 33 is configured as a smooth arc shape, but the structure is not limited to this. Alternatively, the second contact portion 33E on the radially outer peripheral surface of the inner second magnet insertion hole 33 may protrude radially inward toward the center axis C.

[0065] The third outer end portion 33A and the third inner end portion 33B smoothly connect the radially outer outer circumferential surface of the inner second magnet insertion hole 33 with the radially inner inner circumferential surface of the inner second magnet insertion hole 33. Specifically, the pair of third inner end portions 33B protrude circumferentially toward each other. Therefore, the circumferential thickness of the second center rib 33C is thickest at imaginary lines V3 and V4, and gradually decreases radially inward from imaginary line V3. Furthermore, the circumferential thickness of the second center rib 33C gradually decreases radially outward from imaginary line V4. That is, the circumferential thickness of the second center rib 33C is thinnest at the radially central portion between imaginary lines V3 and V4. In other words, the circumferential distance between the pair of third inner end portions 33B is smallest at the radially central portion between imaginary lines V3 and V4.

[0066] To prevent magnetic flux short-circuiting and improve strength, the radial thickness of the first and second center ribs 32C and 33C is typically increased. However, in this embodiment, the radial thickness from imaginary line V1 to imaginary line V2 is intentionally reduced to prevent the first center rib 32C from buckling when the rotor core 21 is radially inwardly compressed by the annular member 8 (described later). Similarly, the radial thickness from imaginary line V3 to imaginary line V4 is intentionally reduced to prevent the second center rib 33C from buckling when the rotor core 21 is radially inwardly compressed by the annular member 8 (described later).

[0067] 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.

[0068] 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 outer 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 inner second magnet insertion hole 33.

[0069] By attaching the annular member 8 , which will be described later, to the rotor core 21 , compressive stress in the radial direction acts on the first end rib 41 , the second end rib 42 , and the third end rib 43 .

[0070] like Figure 2 As shown, the shaft through hole 45 is provided at a position radially inward of the magnet insertion hole 25. The shaft through hole 45 axially penetrates the rotor core 21. The shaft through hole 45 is provided on the same axis as the axis C. The shaft through hole 45 is provided for the shaft 5 to be inserted (see Figure 1 The shaft 5 is, for example, press-fitted into the shaft through-hole 45 and fixed.

[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 functions as a magnetic flux barrier. 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 provision of the weight-reducing portion 46 contributes to the reduction in weight of the rotor core 21.

[0072] The interior of the lightened portion 46 is formed so that the penetration member 47 can penetrate therethrough. The interior of the lightened portion 46 may be filled with a resin material.

[0073] <End panel>

[0074] The end panels 23 are arranged at both ends of the rotor core 21 in the axial direction. The end panels 23 only need to cover at least a plurality of magnet insertion holes 25. The end panels 23 abut against the outer end surface of the rotor core 21 in the axial direction. The end panels 23 are pressed into the shaft 5 and fixed. Figure 4 As shown, the ends of the through-member 47 are fixed to the end panel 23 by fixing members 48. In this embodiment, the fixing members 48 are formed by screws or other members that screw into the through-member 47, but are not limited thereto. The fixing members 48 only need to fix the ends of the through-member 47 to the end panel 23. The fixing members 48 may also be configured by riveting the ends of the through-member 47 to secure it to the end panel 23.

[0075] <Magnet>

[0076] The magnet 22 is formed of a permanent magnet and includes a first magnet 221 , a second magnet 222 , and a third magnet 223 .

[0077] The gap between the magnet 22 and the magnet insertion hole 25 is filled with a resin material.

[0078] The first magnet 221 is press-fitted into the first magnet insertion hole 31. The first magnet 221 is formed into an arc shape having the same curvature and arc center as the first magnet insertion hole 31. When the first magnet 221 is inserted into the first magnet insertion hole 31, both circumferentially outer ends of the first magnet 221 contact the first protrusion 31D.

[0079] The second magnets 222 are press-fitted into the outer second magnet insertion holes 32. A pair of second magnets 222 are provided across the first central rib 32C. A gap is provided between the second magnets 222 and the first central rib 32C. In other words, the second magnets 222 are separated from the second inner end portion 32B.

[0080] In the following description, the side surface of the second magnet 222 facing the second end rib 42 may be referred to as “one end portion”, and the side surface of the second magnet 222 facing the first center rib 32C may be referred to as “the other end portion”.

[0081] Second magnet 222 is formed into an arc shape having the same curvature and arc center as outer second magnet insertion hole 32. Second magnet 222 is thicker than first magnet 221. When second magnet 222 is inserted into outer second magnet insertion hole 32, one end of second magnet 222 contacts second protrusion 32D.

[0082] When the second magnet 222 is inserted into the outer second magnet insertion hole 32, the radially outer circumferential surface of the second magnet 222, from the other end of the second magnet 222 to the outer circumferential surface facing the first intersection V51 on the radial outer side, contacts the first contact portion 32E of the outer second magnet insertion hole 32.

[0083] The third magnet 223 is press-fitted into the inner second magnet insertion hole 33. A pair of third magnets 223 are provided across the second center rib 33C. A gap is provided between the third magnet 223 and the second center rib 33C. In other words, the third magnet 223 is separated from the third inner end portion 33B.

[0084] In the following description, the side surface of the third magnet 223 facing the third end rib 43 may be referred to as “one end”, and the side surface of the third magnet 223 facing the second center rib 33C may be referred to as “the other end”.

[0085] The third magnet 223 is formed into an arc shape having the same curvature and arc center as the inner second magnet insertion hole 33. The third magnet 223 is thicker than the second magnet 222. When the third magnet 223 is inserted into the inner second magnet insertion hole 33, the circumferentially outer end of the third magnet 223 contacts the third protrusion 33D.

[0086] When the third magnet 223 is inserted into the inner second magnet insertion hole 33, the radially outer circumferential surface of the third magnet 223, from the other end of the third magnet 223 to the outer circumferential surface facing the second intersection V52 on the radial outer side, contacts the second contact portion 33E of the inner second magnet insertion hole 33.

[0087] <Ring components>

[0088] like Figure 2 and Figure 3 As shown, the annular member 8 is formed in an annular shape centered on the axis C. The annular member 8 is provided on the outer peripheral surface of the rotor core 21 and covers the rotor core 21 from the radially outer side. The annular member 8 functions as a compression unit that applies a load to the rotor core 21 from the radially outer side toward the radially inner side.

[0089] The annular member 8 can also be formed from a non-magnetic material with low electrical conductivity. Specifically, the annular member 8 can be formed from a metal material such as stainless steel or a synthetic fiber material such as CFRP. Since the annular member 8 is expected to have a higher tensile strength than electromagnetic steel sheets, it is particularly preferable to form it from a synthetic fiber material such as CFRP. The axial length of the annular member 8 is equal to the axial length of the rotor core 21.

[0090] The annular member 8 is fixed to the outer peripheral surface of the rotor core 21 in a state where compressive stress is applied to the rotor core 21 in the radial direction. Specifically, the annular member 8 applies compressive stress to the rotor core 21 by being pressed into the rotor core 21. By providing the annular member 8, it is possible to obtain an additional margin under the negative stress generated by pre-compression, and a stress relief effect brought about by stress bearing / spring parallelization. It should be noted that since the pre-compression effect is proportional to the interference, the radial thickness of the first central rib 32C and the second central rib 33C is inversely proportional to the interference. In addition, by providing the annular member 8, compressive stress can be applied to the second magnet 222 and the third magnet 223 where the centrifugal stress is the largest.

[0091] <Reinforcement Unit>

[0092] Next, the reinforcement means included in the rotor core 21 will be described.

[0093] The reinforcing member is provided between the shaft through-hole 45 and the first magnet insertion hole 31 located on the outermost side in the radial direction. The reinforcing member has a function of increasing the strength of the rotor core 21.

[0094] The penetration member 47 is included in the reinforcement unit. By fixing a pair of end plates 23 to both ends of the penetration member 47, the rotor core 21 can be reinforced toward the inner side in the axial direction.

[0095] The resin material filled in the lightened portion 46 is contained in the reinforcing unit. The interior of the lightened portion 46 is reinforced by the resin material, thereby reinforcing the lightened portion 46 itself.

[0096] The resin material filled between the magnet 22 and the magnet insertion hole 25 functions as a reinforcing member. By reinforcing the space between the magnet 22 and the magnet insertion hole 25 with the resin material, the rotor core 21 can be reinforced.

[0097] The first and second center ribs 32C and 33C are included in the reinforcement unit. When a load is applied to the rotor core 21 via the annular member 8, the first magnet 221 is pressed axially. This axial pressure on the first magnet 221 further compresses the portion enclosed by the imaginary line V5 and the second magnet 222. This further compresses the first and second center ribs 32C and 33C in the portion enclosed by the imaginary line V5 and the second magnet 222, thereby improving the strength of the rotor 4 compared to a structure without center ribs.

[0098] The first contact portion 32E and the second contact portion 33E are included in the reinforcement unit. As described above, when a load is applied to the rotor core 21 via the annular member 8, the portion surrounded by the imaginary line V5 and the second magnet 222 is further compressed. Specifically, the first contact portion 32E is pressed against the radially outer circumference of the second magnet 222, from the other end of the second magnet 222 to the outer circumference facing the first radially outer intersection V51. Furthermore, the second contact portion 33E is pressed against the radially outer circumference of the third magnet 223, from the other end of the third magnet 223 to the outer circumference facing the second radially outer intersection V52.

[0099] In the portion surrounded by the imaginary line V5 and the second magnet 222 , the first contact portion 32E and the second contact portion 33E are further compressed. Therefore, the strength of the rotor 4 can be improved compared to a structure without the first contact portion 32E and the second contact portion 33E.

[0100] (Method for Manufacturing Rotor)

[0101] Next, a method for manufacturing the above-mentioned rotor 4 will be described.

[0102] The method for manufacturing the rotor 4 includes a magnet inserting step and a ring member arranging step.

[0103] In the magnet inserting step, the magnets 22 are respectively inserted into the magnet insertion holes 25 of the rotor core 21 .

[0104] In the annular member placement step, the annular member 8 is placed on the outer peripheral portion of the rotor core 21 while applying compressive stress to the rotor core 21 in the radial direction. In the present embodiment, in the annular member placement step, the annular member 8 is fixed to the outer peripheral surface of the rotor core 21 by pressing the annular member 8 into the rotor core 21. Specifically, the inner diameter of the annular member 8 before being assembled to the rotor core 21 is formed to be smaller than the outer diameter of the rotor core 21. When the annular member 8 is assembled to the rotor core 21, the annular member 8 is pushed wider toward the radial outside and inserted into the rotor core 21 from the axial direction toward the inner peripheral portion of the annular member 8. In the annular member placement step, the annular member 8 is set so that the compressive stress applied to the rotor core 21 when the rotor core 21 is assembled becomes a predetermined value.

[0105] (Effect)

[0106] In the above embodiment, the rotor core 21 is provided with a reinforcing member, thereby increasing the strength of the rotor 4. The rotary electric machine 1 includes the rotor core 21 provided with the reinforcing member. Therefore, according to the above embodiment, a rotor 4 and a rotary electric machine 1 are provided that have increased strength and can be used stably even at high rotation speeds.

[0107] In the above embodiment, the rotor core 21 is lightweighted by providing the lightened portion 46, thereby enabling stable use even at high rotation speeds of the rotor 4. Furthermore, the strength of the rotor core 21 can be increased by arranging a reinforcing member in the lightened portion 46.

[0108] In the above embodiment, the reinforcing means (penetration member 47) is fixed by axially sandwiching the end plates 23 at both ends of the rotor core 21. Therefore, the strength of the rotor core 21 can be improved without affecting the magnetic field.

[0109] In the above embodiment, the resin material is contained in the reinforcing means. Since the resin material can be easily filled into the magnet insertion holes 25 and the inside of the weight-reduced portion 46, the rotor can be easily reinforced.

[0110] In the above embodiment, the first and second center ribs 32C and 33C are included in the reinforcement unit. The first and second center ribs 32C and 33C can improve the strength of the rotor core 21 and support the magnets, thereby facilitating high rotation speed of the rotor 4.

[0111] In this embodiment, a pair of second magnets 222 is provided across first center rib 32C, and a pair of third magnets 223 is provided across second center rib 33C. Generally, providing a center rib supporting magnets 22 is effective in achieving high rotation speed of rotor 4 .

[0112] However, if the center rib is larger (thicker) in both the radial and circumferential directions, magnetic flux short-circuiting of magnet 22 may occur, resulting in reduced torque. If the center rib is larger (thicker) in both the radial and circumferential directions within the rotor core, the circumferential stress resisting centrifugal force increases, but magnetic flux leakage from the magnets also increases. On the other hand, if the center rib is smaller (thinner) in both the radial and circumferential directions, the d-axis inductance increases, potentially reducing the output of rotating electric machine 1.

[0113] In the present embodiment, from the viewpoint of suppressing the occurrence of magnetic flux short-circuiting and reducing the rotational torque, the first magnet insertion hole 31 is not provided with a central rib.

[0114] In the above embodiment, a compression unit is provided to apply a load from radially outside to radially inside the rotor core 21. The strength of the rotor core 21 is ensured by the reinforcement unit, and the rotor core 21 is compressed by the compression unit, thereby achieving higher rotation speed of the rotor 4.

[0115] In the above embodiment, the reinforcing means includes first and second contact portions 32E and 33E, which come into contact with second and third magnets 222 and 223 when a load is applied to the rotor core 21 by the compression means. This facilitates inserting magnets 22 into magnet insertion holes 25 compared to a configuration where magnet insertion holes are pre-defined to minimize the gaps between magnets 22. Furthermore, the compression means generates compressive deformation between the rotor core 21 and first and second contact portions 32E and 33E, thereby securing second and third magnets 222 and 223 and achieving higher rotational speeds for the rotor 4.

[0116] In the above embodiment, second protrusion 32D and third protrusion 33D contact one end of second magnet 222 and third magnet 223, which are press-fitted into second magnet insertion hole 35 (outer second magnet insertion hole 32 and inner second magnet insertion hole 33). By contacting second protrusion 32D and third protrusion 33D with one end of second magnet 222 and third magnet 223, gaps can be created between second outer end 32A and one end of second magnet 222, and between third outer end 33A and one end of third magnet 223, thereby reducing leakage magnetic fields.

[0117] In the above embodiment, the other end of the second magnet 222 is separated from the first center rib 32C. That is, a gap is provided between the other end of the second magnet 222 and the second inner end portion 32B. Similarly, the other end of the third magnet 223 is separated from the second center rib 33C. That is, a gap is provided between the other end of the third magnet and the third inner end portion 33B. Because the gap functions as a magnetic flux barrier, it can improve the performance of the rotor 4.

[0118] In the above embodiment, by using arc-shaped magnets 22, the circumferential thickness and length (radial distance from imaginary line V1 to imaginary line V2 or from imaginary line V3 to imaginary line V3) of the first and second central ribs 32C, 33C can be relatively reduced compared to the case of using linear magnets. Furthermore, the use of arc-shaped magnets 22 offers the advantage of preventing the magnets 22 from being crushed by centrifugal force.

[0119] In the above embodiment, the radial thickness of each magnet is such that the second magnet 222 is thicker than the first magnet 221, and the third magnet 223 is thicker than the second magnet 222 (radial thickness: first magnet 221 < second magnet 222 < third magnet 223). The radial thickness of the second magnet 222 is equal to the radial length between the imaginary lines V1 and V2. The radial thickness of the third magnet 223 is equal to the radial length between the imaginary lines V3 and V4. It should be noted that the magnetic permeance decreases in the reverse order of the radial thickness of each magnet (magnetic permeance: first magnet 221 > second magnet 222 > third magnet 223).

[0120] The rotor core 21 concentrates magnetic flux as it moves radially outward, improving its demagnetization toughness. Therefore, the radial thickness of each magnet can be set such that the first magnet 221 is less than the second magnet 222 and less than the third magnet 223. Originally, the first magnet 221, which has the thinnest radial thickness, acts in the demagnetization direction. However, in this embodiment, the radial thickness of the second and third magnets 222 and 223 is thicker than that of the first magnet 221. This allows the magnetic flux of the second and third magnets 222 and 223 to complement the magnetic flux of the first magnet 221.

[0121] (Other Modifications)

[0122] Hereinafter, modifications of this embodiment will be described.

[0123] In this embodiment, the first end rib 41, the second end rib 42, and the third end rib 43 are described as having the same thickness in the radial direction when viewed from the axial direction, but the present invention is not limited thereto. The first end rib 41, the second end rib 42, and the third end rib 43 may have different thicknesses in the radial direction.

[0124] In the above embodiment, the rotating electrical machine 1 is described as a driving motor mounted on a hybrid vehicle or electric vehicle, but the present invention is not limited thereto. For example, the rotating electrical machine 1 may be a power generation motor, a motor for other purposes, or a rotating electrical machine for purposes other than vehicles (including a generator).

[0125] In the above embodiment, the penetrating member 47 as a reinforcing means is disposed inside the lightened portion 46 , but the present invention is not limited thereto. A configuration may be adopted in which the penetrating member 47 is not disposed inside the lightened portion 46 and the portion is simply filled with a resin material.

[0126] In the above embodiment, the rotor core 21 is described as having end panels 23 at both axial ends, and the through-hole members 47 serving as reinforcement means are fixed to the end panels 23. However, the present invention is not limited thereto. The end panels 23 may be provided at both axial ends of the rotor core 21. For example, in a configuration where the through-hole members 47 are not provided within the weight-reducing portion 46, the end panels 23 may be fixed to both axial ends of the rotor core 21 via the fixing members 48.

[0127] In the above embodiment, the reinforcing unit is described as including the through-hole 47, the first central rib 32C, the second central rib 33C, the first contact portion 32E, and the second contact portion 33E. However, this is not limiting. The reinforcing unit only needs to be provided between the shaft through-hole 45 and the radially outermost first magnet insertion hole 31. Furthermore, the reinforcing unit need not include all of the through-hole 47, the first central rib 32C, the second central rib 33C, the first contact portion 32E, and the second contact portion 33E. The reinforcing unit may be any one of the through-hole 47, the first central rib 32C, the second central rib 33C, the first contact portion 32E, and the second contact portion 33E, or a combination of any selected plurality of reinforcing units.

[0128] In the above embodiment, a pair of outer second magnet insertion holes 32 are described, arranged circumferentially with a first radially extending central rib 32C interposed therebetween. However, the present invention is not limited thereto. The outer second magnet insertion holes 32 may also be provided without the first radially extending central rib 32C. In this case, the outer second magnet insertion holes 32 are provided along the imaginary lines V1 and V2. Without the first central rib 32C, the second magnets 222 may be provided in an arcuate shape that can be press-fitted into the outer second magnet insertion holes 32.

[0129] 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 having a shaft through-hole and magnet insertion holes formed therein, the magnet insertion holes being formed in multiple layers in a radial direction toward a central axis of the shaft through-hole; and a magnet, which is pressed into the magnet insertion hole, The rotor core includes a reinforcing unit between the shaft through hole and the first magnet insertion hole located on the outermost side in the radial direction. A pair of second magnet insertion holes located radially inward of the first magnet insertion holes among the multi-layered magnet insertion holes are arranged circumferentially with a central rib extending in the radial direction interposed therebetween. The rotor includes a compression unit that applies a load to the rotor core from the radially outer side toward the radially inner side. The reinforcement unit includes a contact portion that contacts the magnet when a load is applied to the rotor core by the compression unit. The contact portion is arranged between the end portion on the central rib side of the radially outer circumferential surface of the second magnet insertion hole and the following intersection, which is the intersection of an imaginary line and the radially outer circumferential surface of the second magnet insertion hole, and the imaginary line connects the circumferential outermost end portion of the magnet inserted into the first magnet insertion hole and the center axis of the rotor core.

2. The rotor according to claim 1, wherein: The rotor core has a weight-reducing portion extending through the rotor core in the axial direction. The reinforcement unit is arranged inside the weight-reduced portion.

3. The rotor according to claim 2, wherein: The rotor core has end panels at both ends in the axial direction. The reinforcement unit includes a member that passes through the weight-reducing portion and is fixed to the end panel.

4. The rotor according to claim 1, wherein: The reinforcement unit includes a resin material.

5. The rotor according to claim 1, wherein The reinforcement unit includes the central rib.

6. The rotor according to claim 1, wherein The rotor core has a convex portion protruding toward the radially outer side on the radially inner peripheral surface of the magnet insertion hole. The protrusion contacts one end of the magnet that is press-fitted into the second magnet insertion hole. The contact portion contacts the other end portion of the magnet press-fitted into the second magnet insertion hole.

7. The rotor according to claim 6, wherein: The other end portion of the magnet is provided separately from the central rib.

8. The rotor according to any one of claims 1, 6 and 7, wherein: The magnet insertion hole is provided in an arc shape protruding toward the central axis of the rotor core. The magnet is arranged in an arc shape.

9. A rotating electrical machine, characterized in that: The rotating electrical machine comprises: The rotor according to any one of claims 1 to 8; and The stator is arranged outside the rotor in the radial direction with a gap therebetween.

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