Rotor and IPM motor

Abstract

The rotor includes a rotor magnet and a rotor core. The rotor core has a plurality of steel plates laminated in the thickness direction and magnet insertion holes that penetrate the plurality of steel plates in the lamination direction and into which the rotor magnet is inserted. The rotor core has riveting recesses at the ends in the lamination direction, which are located around the magnet insertion holes and are deeper than the thickness of one steel plate. The steel plate on the outermost surface in the lamination direction among the laminated plurality of steel plates has an inner surface covering portion that covers at least a part of the inner surface of the riveting recess.

Description

Technical Field

[0001] The present invention relates to a rotor and an IPM motor. Background Art

[0002] There is known a rotor in which a plurality of steel plates laminated in the thickness direction are riveted in the lamination direction around a magnet insertion hole, so that the inner surface of the magnet insertion hole is pressed by a magnet inserted into the magnet insertion hole. As such a rotor, for example, Patent Document 1 discloses a rotor in which a recess recessed from the inner surface thereof toward the side opposite to the magnet is formed in a through hole formed in a rotor core and accommodating a magnet, and an open front end portion opening toward the magnet in the recess is in pressure contact with the magnet.

[0003] In the above Patent Document 1, the recess has a shape recessed from the radially inner side surface of the through hole toward the inside. That is, the radially outer end portion of the recess is configured as an open front end portion opening toward the magnet side in the radial direction, and the radially inner end portion on the opposite side thereof is configured as a closed end portion. Further, the recess is formed in a substantially rectangular shape having a pair of circumferential side walls connected to the radially inner side surface of the through hole at substantially right angles.

[0004] Each open front end portion of the recess is plastically deformed outward in the radial direction by caulking the iron core pieces at both axial ends, so as to be pressed against the magnet toward the outside in the radial direction. That is, the magnet is fixed at both axial end portions thereof by the open front end portions of the recess.

[0005] Further, the caulking is so-called riveting, which is performed at the radial center position of the recess from both axial ends of the rotor core by a caulking jig. As a result, a caulking mark is formed at the radial center portion of the recess.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2013-34363

[0009] As described above, in a structure in which a plurality of steel plates laminated in the thickness direction are riveted in the lamination direction around a magnet insertion hole by using a jig, when the steel plate on the outermost surface in the lamination direction is pressed in the lamination direction by the jig, a part of the steel plate located between the caulking recess formed by caulking and the magnet insertion hole is deformed outward in the axial direction.

[0010] On the contrary, in order to prevent the steel plate located between the riveting recess and the magnet insertion hole from deforming as described above, it is conceivable to reduce the force pressing the steel plate in the stacking direction by the jig. However, if the pressing force of the jig on the steel plate is reduced in this way, it may not be possible to sufficiently obtain the force for riveting the plurality of steel plates in the stacking direction. Summary of the Invention

[0011] An object of the present invention is to achieve the following structure: in a rotor in which a plurality of steel plates stacked in the thickness direction are riveted in the stacking direction around a magnet insertion hole, a riveting recess is formed, and the riveting recess can suppress the portion of the steel plate located on the outermost surface in the stacking direction and between the riveting recess and the magnet insertion hole from deforming outward in the axial direction of the stator core, and can obtain the force for riveting the plurality of steel plates in the stacking direction.

[0012] A rotor according to an embodiment of the present invention includes: a rotor magnet; and a rotor core having a plurality of steel plates stacked in the thickness direction and a magnet insertion hole that penetrates the plurality of steel plates in the stacking direction and into which the rotor magnet is inserted. The rotor core has a riveting recess at an end in the stacking direction, which is located around the magnet insertion hole and is deeper than the thickness of one steel plate. The steel plate located on the outermost surface in the stacking direction among the stacked plurality of steel plates has an inner surface covering portion that covers at least a part of the inner surface of the riveting recess.

[0013] An IPM motor according to an embodiment of the present invention includes: a rotor having the above structure; and a stator having a stator coil and a stator core.

[0014] According to the rotor of an embodiment of the present invention, the following structure can be realized: in a rotor in which a plurality of steel plates stacked in the thickness direction are riveted in the stacking direction around a magnet insertion hole, a riveting recess is formed, and the riveting recess can suppress the portion of the steel plate located on the outermost surface in the stacking direction and between the riveting recess and the magnet insertion hole from deforming outward in the axial direction of the stator core, and can obtain the force for riveting the plurality of steel plates in the stacking direction. Brief Description of the Drawings

[0015] Figure 1 FIG. schematically shows a schematic structure of a motor according to an embodiment in a cross-section including a central axis line.

[0016] Figure 2 FIG. is a perspective view showing a schematic structure of a stator core.

[0017] Figure 3 FIG. is Figure 2 a cross-sectional view taken along line III-III in

[0018] Figure 4It is a schematic diagram for explaining the method of forming the riveting recess.

[0019] Figure 5 It is a schematic diagram for explaining the method of forming the riveting recess.

[0020] Figure 6 It is a schematic diagram for explaining the method of forming the riveting recess in the rotor of other embodiments.

[0021] Figure 7 It is a diagram showing the structure of the riveting recess of the rotor of other embodiments. Detailed Embodiments

[0022] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same or corresponding parts in the drawings are denoted by the same reference numerals and their description will not be repeated. In addition, the dimensions of the components in each drawing do not faithfully show the actual dimensions of the components and the dimensional ratios of the components.

[0023] In addition, hereinafter, in the description of the motor 1, the direction parallel to the central axis P of the rotor 2 is referred to as the "axial direction", the direction orthogonal to the central axis P is referred to as the "radial direction", and the direction along the arc centered on the central axis P is referred to as the "circumferential direction". However, the orientation during the use of the motor 1 is not limited by this definition of the direction.

[0024] In addition, in the following description, expressions such as "fix", "connect", "join", and "mount" (hereinafter referred to as fixing, etc.) include not only the case where components are directly fixed to each other, etc., but also the case where they are fixed via other components. That is, in the following description, the expressions of fixing, etc. include the meaning of direct and indirect fixing, etc. of components to each other.

[0025] (Structure of the motor)

[0026] Figure 1 A schematic configuration of a motor 1 having a rotor 2 according to an exemplary embodiment of the present invention is shown. The motor 1 includes a rotor 2, a stator 3, and a housing 4. The rotor 2 rotates around the central axis P with respect to the stator 3. In the present embodiment, the motor 1 is a so-called inner rotor type motor in which the rotor 2 is rotatably located within a cylindrical stator 3 around the central axis P.

[0027] The rotor 2 includes a shaft 20, a rotor core 21, and a rotor magnet 22. The rotor 2 is located radially inside the stator 3 and is rotatable with respect to the stator 3.

[0028] The stator 3 is housed in the outer housing 4. In the present embodiment, the stator 3 has a cylindrical shape. The rotor 2 is located on the radially inner side of the stator 3. That is, the stator 3 is located at a position radially opposed to the rotor 2. The rotor 2 is rotatably located on the radially inner side of the stator 3 about the central axis P.

[0029] The stator 3 includes a stator core 31 and a stator coil 32. The stator coil 32 is wound around the stator core 31. A detailed description of the structure of the stator 3 is omitted.

[0030] (Structure of the rotor)

[0031] Figure 2 FIG. is a perspective view showing a schematic structure of the rotor core 21. In the present embodiment, the rotor core 21 has a cylindrical shape extending along the central axis P. The rotor core 21 has a through hole 21a extending along the central axis P. The shaft 20 is fixed to the rotor core 21 in a state of axially penetrating the through hole 21a. Thus, the rotor core 21 rotates together with the shaft 20.

[0032] In addition, in the present embodiment, the rotor core 21 has a plurality of magnet insertion holes 21b provided at a predetermined interval in the circumferential direction. The plurality of magnet insertion holes 21b penetrate the rotor core 21 in the axial direction. Rotor magnets 22 are inserted into these magnet insertion holes 21b.

[0033] The rotor core 21 has a plurality of disk-shaped rotor core plates 23 formed in a predetermined shape and laminated in the thickness direction. The plurality of rotor core plates 23 are electromagnetic steel sheets. The plurality of rotor core plates 23 each have an opening 23a that forms a part of the magnet insertion hole 21b.

[0034] The rotor core plate 23 corresponds to the steel plate of the present invention.

[0035] The plurality of rotor core plates 23 laminated in the thickness direction are riveted in the lamination direction around the magnet insertion hole 21b. That is, the rotor core 21 has a plurality of riveting recesses 24 recessed in the axial direction around the magnet insertion hole 21b. In the present embodiment, the riveting recesses 24 are located at a position radially inner than the magnet insertion hole 21b in the rotor core 21. In addition, in Figure 2 the example shown, two riveting recesses 24 are located at a position radially inner than the magnet insertion hole 21b. However, the number of riveting recesses 24 located at a position radially inner than the magnet insertion hole 21b may be one or three or more.

[0036] Figure 3 is Figure 2 a cross-sectional view taken along line III-III in Figure 3 FIG. is a view showing the structure of the riveting recess 24.

[0037] As shown in Figure 3As shown, the riveting recesses 24 are located at both axial ends of the rotor core 21. As will be described in detail later, each crimping recess 24 is formed by pressing the jig M against the rotor core plate 23 on the outermost surface in the stacking direction among the plurality of rotor core plates 23 stacked in the thickness direction. The depth of the riveting recess 24 is deeper than the thickness of at least one rotor core plate 23. Alternatively, the riveting recess 24 may be formed only at one axial end of the rotor core 21. The rotor core plate 23 on the aforementioned outermost surface refers to the rotor core plate 23 on the outermost side in the axial direction of the rotor core 21 among the plurality of rotor core plates 23 stacked in the thickness direction.

[0038] As described later Figure 4 and Figure 5 As shown, the jig M is a columnar member. The jig M has a tapered portion at the front end with a diameter that decreases towards the front end. Alternatively, the front end of the jig M may be hemispherical.

[0039] The bottom 24a of the riveting recess 24 formed by pressing the front end of the jig M with the above-described structure against the rotor core plate 23 on the outermost surface in the stacking direction among the plurality of rotor core plates 23 stacked in the thickness direction has a shape along the front end of the jig M. That is, in the present embodiment, the bottom 24a of the riveting recess 24 is circular when the rotor core 21 is viewed axially.

[0040] By forming the riveting recess 24 on the rotor core 21 by pressing the front end of the jig M against the rotor core plate 23, the intermediate portion 23c between the riveting recess 24 and the magnet insertion hole 21b among the plurality of rotor core plates 23 forming the axial ends of the rotor core 21 can be moved towards the inside of the magnet insertion hole 21b. That is, in a state where the above-described riveting recess 24 is formed on the rotor core 21, a part of the inner surface of the magnet insertion hole 21b moves towards the inside of the magnet insertion hole 21b.

[0041] Thereby, a part of the inner surface of the magnet insertion hole 21b is pressed against the rotor magnet 22 inserted into the magnet insertion hole 21b. Therefore, the rotor magnet 22 is held by its inner surface within the magnet insertion hole 21b.

[0042] A part of the rotor core plate 23 on the outermost surface in the stacking direction among the plurality of rotor core plates 23 stacked in the thickness direction is positioned on the side surface of the riveting recess 24. That is, the rotor core plate 23 on the outermost surface in the aforementioned stacking direction among the plurality of stacked rotor core plates 23 has an inner surface covering portion 23b that covers at least a part of the inner surface of the riveting recess 24. The rotor core plate 23 on the aforementioned outermost surface is the rotor core plate 23 at the outermost end in the axial direction of the rotor core 21 among the plurality of stacked rotor core plates 23.

[0043] As described above, in the present embodiment, the rotor 2 includes a rotor magnet 22 and a rotor core 21. The rotor core 21 has a plurality of rotor core plates 23 laminated in the thickness direction and a magnet insertion hole 21b that penetrates the plurality of rotor core plates 23 in the lamination direction and into which the rotor magnet 22 is inserted. The rotor core 21 has, at an end in the lamination direction, a riveting recess 24 that is located around the magnet insertion hole 21b and is deeper than the thickness of one rotor core plate 23. The rotor core plate 23 on the outermost surface in the lamination direction among the plurality of laminated rotor core plates 23 has an inner surface covering portion 23b that covers at least a part of the inner surface of the riveting recess 24.

[0044] In this way, by using the jig M to form, on the rotor core 21, a riveting recess 24 whose inner surface is covered at least in part by the inner surface covering portion 23b of the rotor core plate 23 on the outermost surface in the lamination direction among the plurality of rotor core plates 23 that constitute the rotor core 21, it is possible to plastically deform the inner surface covering portion 23b of the rotor core plate 23 while moving the inner surface of the riveting recess 24 covered by the inner surface covering portion 23b of the rotor core plate 23 toward the inside of the magnet insertion hole 21b.

[0045] Through such plastic deformation of the inner surface covering portion 23b, it is possible to maintain the inner surface of the riveting recess 24 formed by the jig M. Therefore, it is possible to maintain the state in which the inner surface of the magnet insertion hole 21b is pressed against the rotor magnet 22 inserted into the magnet insertion hole 21b. Thereby, the rotor magnet 22 can be held more reliably in the magnet insertion hole 21b.

[0046] The inner surface covering portion 23b preferably covers at least a part of the inner surface of the riveting recess 24 that is close to the magnet insertion hole 21b. The part of the inner surface of the riveting recess 24 that is close to the magnet insertion hole 21b refers to the part of the inner surface of the riveting recess 24 that has the smallest distance from the opening edge portion of the magnet insertion hole 21b when the riveting recess 24 is viewed in the lamination direction.

[0047] In the present embodiment, the inner surface covering portion 23b covers the entire inner surface of the riveting recess 24. That is, in the present embodiment, the inner surface covering portion 23b is cylindrical.

[0048] In this way, by covering the entire inner surface of the riveting recess 24 with the inner surface covering portion 23b of the rotor core plate 23 on the outermost surface among the plurality of rotor core plates 23 that constitute the rotor core 21, the strength of the inner surface covering portion 23b can be improved.

[0049] Therefore, through the plastic deformation of the inner surface covering portion 23b, it is possible to more reliably hold the intermediate portion 23c of the rotor core 21 between the riveting recess 24 and the magnet insertion hole 21b in a state of moving inwardly of the magnet insertion hole 21b. Therefore, it is possible to more reliably hold the state of pressing the inner surface of the magnet insertion hole 21b against the rotor magnet 22 inserted into the magnet insertion hole 21b. Thus, the rotor magnet 22 can be more reliably held within the magnet insertion hole 21b.

[0050] In addition, the inner surface covering portion 23b may also be an annular shape covering the inner surface of the riveting recess 24. That is, the inner surface covering portion 23b may also be an annular shape covering at least a portion of the inner surface of the riveting recess 24 close to the magnet insertion hole 21b and extending in the circumferential direction of the riveting recess 24 when observing the rotor core 21 in the above-described lamination direction.

[0051] In this way, by forming the inner surface covering portion 23b of the rotor core plate 23 located on the outermost surface among the plurality of rotor core plates 23 constituting the rotor core 21 into an annular shape, the strength of the inner surface covering portion 23b can be improved compared to the case where the inner surface covering portion is not annular.

[0052] Thus, through the plastic deformation of the inner surface covering portion 23b using the jig M, the intermediate portion 23c of the rotor core 21 between the riveting recess 24 and the magnet insertion hole 21b can be held in a state of moving inwardly of the magnet insertion hole 21b. Therefore, it is possible to more reliably hold the state of pressing the inner surface of the magnet insertion hole 21b against the rotor magnet 22 inserted into the magnet insertion hole 21b.

[0053] The inner surface covering portion 23b may not be annular but columnar extending in the depth direction of the riveting recess 24. In addition, the rotor core plate 23 located on the outermost surface may also have a plurality of inner surface covering portions 23b on the inner circumferential surface of the riveting recess 24.

[0054] In the present embodiment, when observing the riveting recess 24 from a direction orthogonal to the above-described lamination direction, at least a part of the inner surface covering portion 23b overlaps with the rotor magnet 22. That is, the inner surface covering portion 23b covers a part of the side surface of the riveting recess 24 close to the magnet insertion hole 21b, and when observing the riveting recess 24 from a direction orthogonal to the above-described lamination direction, at least a part of the inner surface covering portion 23b overlaps with the rotor magnet 22.

[0055] Thus, by using the jig M to form the riveting recess 24 on the rotor core 21, which is covered by the inner surface covering portion 23b that overlaps with the rotor magnet 22 in the stacking direction when observing the riveting recess 24 in the direction orthogonal to the stacking direction, it is possible to plastically deform the inner surface covering portion 23b more reliably in a state where the inner surface of the riveting recess 24 covered by the inner surface covering portion 23b is moved toward the magnet insertion hole 21b.

[0056] Through the plastic deformation of the inner surface covering portion 23b of the jig M used in this way, the intermediate portion 23c of the rotor core 21 located between the riveting recess 24 and the magnet insertion hole 21b can be moved toward the rotor magnet 22 inserted into the magnet insertion hole 21b. Thereby, the inner surface of the magnet insertion hole 21b can be pressed more reliably against the rotor magnet 22 inserted into the magnet insertion hole 21b. Therefore, the rotor magnet 22 can be held more reliably in the magnet insertion hole 21b.

[0057] In the present embodiment, the riveting recess 24 is located at a position radially inside the magnet insertion hole 21b in the rotor core 21. Thereby, the rotor magnet 22 can be arranged as much as possible on the radially outer side of the rotor core 21 and held in the magnet insertion hole 21b. Thereby, the magnetic characteristics of the motor 1 can be improved and the rotor magnet 22 can be held in the magnet insertion hole 21b.

[0058] In the present embodiment, the riveting recess 24 is located at both ends of the rotor core 21 in the stacking direction. The rotor core plates 23 located on the outermost surface at both ends of the rotor core 21 in the stacking direction each have an inner surface covering portion 23b.

[0059] Thereby, the rotor core 21 has the riveting recess 24 at both ends in the stacking direction. Therefore, at both ends of the rotor core 21 in the stacking direction, it is possible to hold the intermediate portion 23c located between the riveting recess 24 and the magnet insertion hole 21b in a state of moving inwardly of the magnet insertion hole 21b. Thereby, the rotor magnet 22 inserted into the magnet insertion hole 21b of the rotor core 21 can be held more reliably in the magnet insertion hole 21b.

[0060] In addition, as Figure 3 shown, when observing the riveting recess 24 from the stacking direction, the shortest distance D between the riveting recess 24 and the magnet insertion hole 21b is smaller than the size W of the rotor magnet 22 in the radial direction of the rotor 2. The shortest distance D is the shortest distance between the opening edge portion of the riveting recess 24 closest to the opening edge portion of the magnet insertion hole 21b and the opening edge portion of the magnet insertion hole 21b closest to the opening edge portion of the riveting recess 24.

[0061] Accordingly, the riveting recess 24 is located close to the rotor magnet 22. Thus, when forming the riveting recess 24 on the rotor core 21 using the jig M, the intermediate portion 23c in the rotor core 21 between the riveting recess 24 and the magnet insertion hole 21b is moved toward the rotor magnet 22 inserted into the magnet insertion hole 21b, and the inner surface of the magnet insertion hole 21b can be pressed against the rotor magnet 22 inserted into the magnet insertion hole 21b. Therefore, the rotor magnet 22 can be more reliably held within the magnet insertion hole 21b.

[0062] (Method of forming the riveting recess)

[0063] Next, a method of forming the riveting recess 24 having the above structure will be described.

[0064] Figure 4 and Figure 5 Schematically shows a state in which the jig M is pressed against a plurality of rotor core plates 23 laminated in the thickness direction along the lamination direction of the rotor core plate 23.

[0065] As Figure 4 shown, each of the plurality of rotor core plates 23 laminated in the thickness direction has a riveting through hole 23d located near the opening 23a. A cavity V is formed through the riveting through holes 23d of the plurality of rotor core plates 23. That is, the rotor core before forming the riveting recess 24 has a cavity V in the portion where the riveting recess 24 is to be formed. The cavity V is covered by the rotor core plate 23 on the outermost surface in the lamination direction of the plurality of rotor core plates 23.

[0066] At a position overlapping with the cavity V when observing the plurality of rotor core plates 23 from the above lamination direction, the jig M is pressed against the rotor core plate 23 on the outermost surface. Thus, as Figure 5 shown, the front end portion of the jig M presses the rotor core plate 23 on the outermost surface into the cavity V. The diameter of the front end portion of the jig M is larger than the diameter of the cavity V. Therefore, the front end portion of the jig M presses the rotor core plate 23 on the outermost surface into the cavity V and pushes the cavity V radially outward.

[0067] Accordingly, as Figure 3 shown, a riveting recess 24 is formed on the rotor core 21, the inner surface of which is covered by a part of the rotor core plate 23 on the outermost surface, namely the inner surface covering portion 23b. By forming the riveting recess 24 on the rotor core 21, the intermediate portion 23c in the rotor core 21 between the riveting recess 24 and the magnet insertion hole 21b moves toward the inside of the magnet insertion hole 21b. Thereby, the inner surface of the magnet insertion hole 21b is pressed against the rotor magnet 22 inserted into the magnet insertion hole 21b. Therefore, the rotor magnet 22 is held within the magnet insertion hole 21b.

[0068] Moreover, as described above, by covering the inner surface of the riveting recess 24 with the inner surface covering portion 23b, the inner surface of the riveting recess 24 can be maintained. As a result, the intermediate portion 23c in the rotor core 21 between the riveting recess 24 and the magnet insertion hole 21b is maintained in a state of moving inwardly of the magnet insertion hole 21b, and thus the inner surface of the magnet insertion hole 21b can be maintained in a state of being pressed against the rotor magnet 22. Thereby, the rotor magnet 22 can be more reliably held within the magnet insertion hole 21b.

[0069] In addition, the formation of the riveting recess 24 using the jig M as described above can be performed only at one end in the axial direction of the rotor core 21, can be performed simultaneously at both ends in the axial direction of the rotor core 21, or can be performed at both ends in the axial direction of the rotor core 21 at different timings.

[0070] (Other embodiments)

[0071] The embodiments of the present invention have been described above, but the above embodiments are merely examples for implementing the present invention. Therefore, the present invention is not limited to the above embodiments, and the above embodiments can be appropriately modified and implemented without departing from the gist thereof.

[0072] In the above embodiment, the entire surface of the inner surface of the riveting recess 24 is covered by the inner surface covering portion 23b of the rotor core plate 23. However, it is also possible that a part of the inner surface of the riveting recess is covered by the inner surface covering portion of the rotor core plate.

[0073] In the above embodiment, when forming the riveting recess 24 on the rotor core 21 using the jig M, the jig M is pressed into the cavity V covered by the rotor core plate 23 located on the outermost surface. However, the rotor core plate located on the above outermost surface may also have a through hole. Specifically, as Figure 6 shown, the rotor core plate 23 located on the outermost surface among the plurality of rotor core plates 23 laminated in the thickness direction may also have a rotor core plate through hole 23e connected to the cavity V. After the front end portion of the jig M is pressed into the rotor core plate through hole 23e, it is pressed into the cavity V, thereby forming a riveting recess on the rotor core 21.

[0074] Thereby, as Figure 7 shown, a riveting recess 124 whose side surface is covered by the annular inner surface covering portion 123b of the rotor core plate 23 located on the outermost surface can be formed.

[0075] In addition, the riveting recess 124 can be formed at both axial ends of the rotor core 21, or can be formed only at one end of the two axial ends of the rotor core 21. In addition, only a part of the side surface of the riveting recess 124 may be covered by the inner surface covering portion.

[0076] Moreover, one of the axial end portions of the rotor core 21 may be formed, as shown in Figure 7 , with a riveting recess 124 whose side surface is covered by an annular inner surface covering portion 123b, and the other end portion may be formed, as shown in Figure 3 , with a riveting recess 24 whose entire surface is covered by the inner surface covering portion 23b.

[0077] In the above-described embodiment, the inner surface covering portion 23b covering the inner surface of the riveting recess 24 is a part of the rotor core plate 23 located on the outermost surface among the plurality of rotor core plates 23 laminated in the thickness direction. However, the inner surface covering portion covering the inner surface of the riveting recess may also be a part of a plurality of rotor cores including the rotor core located on the outermost surface.

[0078] In the above-described embodiment, when observing the riveting recess 24 from a direction orthogonal to the above-described lamination direction, at least a part of the inner surface covering portion 23b covering the inner surface of the riveting recess 24 overlaps with the rotor magnet 22. However, when observing the riveting recess from a direction orthogonal to the above-described lamination direction, at least a part of the inner surface covering portion may not overlap with the rotor magnet.

[0079] In the above-described embodiment, the riveting recess 24 is located at a position radially inward of the magnet insertion hole 21b in the rotor core 21. However, the riveting recess may also be located at a position radially outward of the magnet insertion hole in the rotor core.

[0080] In the above-described embodiment, the jig M has a tapered portion at the front end. However, the jig may also have a protruding portion protruding in the axial direction of the jig at the front end, and may also have an inclined surface inclined with respect to the axis of the jig.

[0081] In the above-described embodiment, the rotor core plate 23 is an electromagnetic steel sheet. However, the rotor core plate may also be a plate member other than the electromagnetic steel sheet.

[0082] Industrial Applicability

[0083] The present invention can be applied to a rotor having a riveting recess formed by riveting a plurality of rotor core plates laminated in the thickness direction in the lamination direction.

[0084] (Reference Signs)

[0085] 1 Motor

[0086] 2 Rotor

[0087] 3 Stator

[0088] 4 Housing

[0089] 20 Shaft

[0090] 21 Rotor core

[0091] 21a Through hole

[0092] 21b Magnet insertion hole

[0093] 22 Rotor magnet

[0094] 23 Rotor core plate

[0095] 23a Opening

[0096] 23b, 123b Inner surface covering portion

[0097] 23c Middle portion

[0098] 23d Through hole for riveting

[0099] 23e Rotor core plate through hole

[0100] 24, 124 Riveting recess

[0101] 24a Bottom

[0102] 31 Stator core

[0103] 32 Stator coil

[0104] M Fixture

[0105] P Central axis

[0106] V Void portion

[0107] W Dimension of the rotor magnet in the radial direction of the rotor

[0108] D Shortest distance between the riveting recess and the magnet insertion hole

Claims

1. A rotor, comprising: a rotor magnet; and a rotor core having a plurality of steel plates laminated in a thickness direction and a magnet insertion hole that penetrates the plurality of steel plates in a lamination direction and into which the rotor magnet is inserted, wherein, the rotor core has, at an end portion in the lamination direction, a riveting recess that is located around the magnet insertion hole and is deeper than the thickness of one steel plate, at least a part of the plurality of laminated steel plates has a riveting through-hole that penetrates in the lamination direction, and the steel plate located on the outermost surface in the lamination direction among the plurality of laminated steel plates has an inner surface covering portion that covers at least a part of the inner surface of the riveting recess, the inner surface covering portion contacts at least a part of the inner circumferential surface of the riveting through-hole.

2. The rotor according to claim 1, wherein, the inner surface covering portion covers at least a part of the inner surface of the riveting recess that is close to the magnet insertion hole.

3. The rotor according to claim 2, wherein, the inner surface covering portion covers a part of the side surface of the riveting recess that is close to the magnet insertion hole, and when observing the riveting recess from a direction orthogonal to the lamination direction, at least a part of the inner surface covering portion overlaps with the rotor magnet.

4. The rotor according to claim 2, wherein, the inner surface covering portion is annular, the inner surface covering portion covers at least a part of the inner surface of the riveting recess that is close to the magnet insertion hole, and extends in the circumferential direction of the riveting recess when observing the rotor core from the lamination direction.

5. The rotor according to claim 3, wherein, the inner surface covering portion is annular, the inner surface covering portion covers at least a part of the inner surface of the riveting recess that is close to the magnet insertion hole, and extends in the circumferential direction of the riveting recess when observing the rotor core from the lamination direction.

6. The rotor according to claim 2, wherein, the inner surface covering portion covers the entire inner surface of the riveting recess.

7. The rotor according to any one of claims 1 to 6, wherein, the riveting recess is located at a position in the rotor core that is more radially inward than the magnet insertion hole.

8. The rotor according to any one of claims 1 to 6, wherein, the riveting recess is located at both end portions of the rotor core in the lamination direction, at both end portions of the rotor core in the lamination direction, the steel plates located on the outermost surface respectively have the inner surface covering portion.

9. The rotor according to claim 7, wherein, the riveting recess is located at both end portions of the rotor core in the lamination direction, at both end portions of the rotor core in the lamination direction, the steel plates located on the outermost surface respectively have the inner surface covering portion.

10. An IPM motor, comprising: the rotor according to any one of claims 1 to 9; and a stator having a stator coil and a stator core.

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