Rotor, IPM motor provided with the rotor, and manufacturing method of the rotor

Abstract

A rotor includes a cylindrical rotor core having a plurality of core plates laminated in a thickness direction and a magnet insertion hole extending in an axial direction, and a magnet inserted into the magnet insertion hole. At least one of the plurality of core plates is a first core plate having a protruding portion protruding toward an inside of the magnet insertion hole of the rotor core and contacting the magnet, a leading end portion of the protruding portion being located in the magnet insertion hole at a position closer to a magnet insertion direction in which the magnet is inserted into the magnet insertion hole than a base end portion of the protruding portion, and being sandwiched by the magnet and an inner surface of the magnet insertion hole that is constituted by an inner surface of a core plate different from the first core plate having the protruding portion.

Description

Technical Field

[0001] The present invention relates to a rotor, an IPM motor having the rotor, and a method for manufacturing the rotor. Background Technology

[0002] In rotors for IPM motors, where a magnet is inserted into a magnet insertion hole, it is known to have a structure that holds the magnet in place by a protrusion extending into the interior of the magnet insertion hole. For example, Patent Document 1 discloses an IPM rotor that uses the restoring force of a spring plate portion of an iron chip protruding toward the inside of the hole to fix the magnet in the width direction of the hole.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2018 / 189822

[0006] In the IPM rotor disclosed in Patent Document 1, the magnet is pressed against the outer surface of the hole by the elastic restoring force of the spring plate. Therefore, in the structure of Patent Document 1, when the rotor rotates, centrifugal force is applied to the magnet, causing the spring plate to repeatedly deform. This reduces the strength of the spring plate, potentially decreasing the force holding the magnet. Therefore, in the rotor for an IPM motor, a structure is required that can suppress the decrease in the force holding the magnet. Summary of the Invention

[0007] The purpose of this invention is to provide a structure in the rotor of an IPM motor that can suppress the decrease in the force of the retaining magnet.

[0008] A rotor according to one embodiment of the present invention comprises: a cylindrical rotor core having a plurality of core plates stacked along its thickness direction and a magnet insertion hole extending along its axial direction; and a magnet inserted into the magnet insertion hole. In the rotor, at least one of the plurality of core plates is a first core plate having a protrusion that protrudes toward the interior of the magnet insertion hole of the rotor core and contacts the magnet. The front end of the protrusion is located within the magnet insertion hole at a position further than the base end of the protrusion in the direction in which the magnet is inserted into the magnet insertion hole, i.e., the magnet insertion direction, and is sandwiched between the magnet and an inner surface of the inner surface of the magnet and the magnet insertion hole, which is composed of a core plate different from the first core plate having the protrusion.

[0009] An IPM motor according to one embodiment of the present invention includes: a rotor having the above-described structure; and a stator having stator coils and a stator core.

[0010] A method for manufacturing a rotor according to an embodiment of the present invention is a method for manufacturing a rotor having the above-described structure. The manufacturing method includes: a core plate stacking process, in which a plurality of core plates are stacked in the thickness direction to obtain a cylindrical rotor core having a magnet insertion hole extending along the axial direction; and a magnet insertion process, in which a magnet is inserted into the magnet insertion hole of the rotor core. In the magnet insertion process, by inserting the magnet into the magnet insertion hole, the magnet is used to position the front end of the protrusion relative to the base end of the protrusion in the insertion direction of the magnet, and the front end of the protrusion is clamped between the magnet and the inner surface of the magnet insertion hole.

[0011] Invention Effects

[0012] According to an embodiment of the present invention, the rotor can provide a structure that can suppress the reduction of the force holding the magnet. Attached Figure Description

[0013] Figure 1 This is a cross-sectional view showing the schematic structure of the IPM motor according to Embodiment 1.

[0014] Figure 2 This is a top view of the rotor in Embodiment 1.

[0015] Figure 3 yes Figure 2 A magnified view of a portion of the image.

[0016] Figure 4 yes Figure 3 Sectional view along line IV-IV.

[0017] Figure 5 This is a partial top view of the basic iron core plate.

[0018] Figure 6 This is a partial top view of the first core plate.

[0019] Figure 7 This is a partial top view of the second core plate.

[0020] Figure 8 This is a diagram illustrating the manufacturing method of the rotor according to Embodiment 1.

[0021] Figure 9 The rotor of the modified embodiment 1 is equivalent to Figure 4 The image.

[0022] Figure 10 This is a partial top view of the third core plate.

[0023] Figure 11 It is equivalent to the rotor of embodiment 2. Figure 4 The image.

[0024] Figure 12 This is a partial top view of the second core plate in Embodiment 3.

[0025] Figure 13 It is equivalent to the rotor of embodiment 3. Figure 4 The image.

[0026] Figure 14 It is equivalent to the rotor in other embodiments. Figure 4 The image.

[0027] Figure 15 This is a cross-sectional view of the first core plate in another embodiment. Detailed Implementation

[0028] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, the same or equivalent parts in the drawings will be labeled with the same symbols without repeating their descriptions. Also, the dimensions of the constituent parts in the drawings do not faithfully represent the actual dimensions of the constituent parts or the dimensional ratios of each constituent part.

[0029] Furthermore, in the following description of motor 1, the direction parallel to the central axis P of rotor 2 will be referred to as the "axial direction", the direction orthogonal to the central axis P will be referred to as the "radial direction", and the direction along the arc centered on the central axis P will be referred to as the "circumferential direction". However, it is not intended to limit the orientation of rotor 2 during use by means of this definition.

[0030] In addition, the direction in which the magnet 22 is inserted into the magnet insertion hole 24 will be referred to as the "magnet insertion direction", the side where the front end of the magnet 22 inserted into the magnet insertion hole 24 is located will be referred to as the "axis direction side" of the rotor 2, and the opposite side will be referred to as the "axis direction other side".

[0031] In addition, in the following description, the "length direction" and "width direction" of magnet 22 and through hole refer to the length direction and width direction of magnet 22 and through hole when rotor 2 is viewed along the axial direction.

[0032] Furthermore, in the following explanation, "same" includes not only cases of strict sameness, but also the range that can be considered substantially the same. Additionally, "consistent" includes not only cases of strict consistency, but also the state that can be considered substantially consistent.

[0033] Furthermore, in the following explanation, terms such as "fixed," "connected," and "installed" (hereinafter referred to as "fixed, etc.") mean not only cases where parts are directly fixed to each other, but also cases where parts are fixed via other parts. That is, in the following explanation, "fixed, etc." means both direct and indirect fixing of parts to each other.

[0034] (Implementation Method 1)

[0035] (Structure of a motor)

[0036] Figure 1 A schematic structure of an IPM motor, i.e., motor 1, with a rotor 2 according to an exemplary embodiment of the present invention is shown. Motor 1 includes a rotor 2, a stator 3, a housing 4, and a shaft 20. The rotor 2 is the rotor for an IPM motor, wherein magnets are embedded within the rotor. The rotor 2 rotates relative to the stator 3 about a central axis P. In this embodiment, motor 1 is a so-called internal rotor type motor in which the rotor 2 is rotatably located within a cylindrical stator 3 about a central axis P.

[0037] The rotor 2 has a rotor core 21 and a magnet 22. The rotor 2 is located radially inside the stator 3 and is capable of rotating relative to the stator 3.

[0038] The rotor core 21 is cylindrical and extends along the central axis P. The shaft 20, extending along the central axis P, is fixed to the rotor core 21 in a through-axis direction. Thus, the rotor core 21 and the shaft 20 rotate together.

[0039] The rotor core 21 is constructed by stacking multiple circular core plates 25 along the thickness direction. The multiple core plates 25 are made of electromagnetic steel plates. The rotor core 21 has magnet insertion holes 24 that extend along the axial direction when the multiple core plates 25 are stacked along the thickness direction.

[0040] Figure 2 This is a diagram showing rotor 2 viewed along its axial direction. (See diagram below.) Figure 2 As shown, in this embodiment, the rotor core 21 has 24 magnet insertion holes 24. Magnets 22 are housed in each of the 24 magnet insertion holes 24. The 24 magnet insertion holes 24 are arranged in groups of three, forming eight groups arranged symmetrically about the central axis P of the rotor core 21. Furthermore, the number, position, and length direction of the magnet insertion holes 24 can also be... Figure 2 The quantities, positions, and length directions shown are different.

[0041] Magnet 22 is a cuboid extending along its axial direction. That is, magnet 22 is rectangular when viewed along the axial direction of rotor 2. The length of magnet 22 along its axial direction is the same as or slightly shorter than the length of magnet insertion hole 24 along its axial direction. Magnet 22 is inserted into magnet insertion hole 24 from the other side of rotor 2 along the magnet insertion direction and is housed within magnet insertion hole 24. In the state of being housed within magnet insertion hole 24, magnet 22 is held by the protrusion 62 of the first core plate 60, which will be described later, among the plurality of core plates 25. The holding structure of magnet 22 by the plurality of core plates 25 will be described later.

[0042] The stator 3 is housed within the housing 4. In this embodiment, the stator 3 is cylindrical. The rotor 2 is located radially inside the stator 3. That is, the stator 3 is located radially opposite the rotor 2. The rotor 2 is rotatably located radially inside the stator 3 with respect to the central axis P.

[0043] The stator 3 has a stator core 31 and a stator coil 36. The stator core 31 is a cylindrical shape extending along the axial direction. The stator coil 36 is wound around the stator core 31. The stator 3 has the same structure as a general stator. Therefore, a detailed description of the stator 3 is omitted.

[0044] Next, refer to Figures 3 to 8 The rotor 2 of this embodiment will be described in detail.

[0045] Figure 3 It is shown in magnification Figure 2 The part of the diagram enclosed by the dashed line. Figure 4 yes Figure 3 A cross-sectional view along line IV-IV. (See attached image.) Figure 4 As shown, in the rotor core 21, multiple core plates 25 are stacked along the thickness direction. The multiple core plates 25 include a basic core plate 50, a first core plate 60, and a second core plate 70. The inner surface of the magnet insertion hole 24 of the rotor core 21 includes the inner surface of the through hole 51 of the basic core plate 50, the inner surface of the through hole 61 of the first core plate 60, and the inner surface of the through hole 71 of the second core plate 70.

[0046] like Figure 4 As shown, in the rotor core 21, the basic core plate 50, the first core plate 60 and the second core plate 70 stacked in a specified order are stacked as a stacking group 27, and multiple stacking groups 27 are stacked along the axial direction.

[0047] In this embodiment, the laminate group 27 includes a first core plate 60, a second core plate 70, and a plurality of basic core plates 50. The second core plates 70 are laminated adjacent to the first core plates 60 on one side of the axial direction. Multiple basic core plates 50 are continuously laminated relative to the second core plates 70 on one side of the axial direction.

[0048] Figure 5 This is an enlarged view showing the basic core plate 50 composed of... Figure 2 The diagram shows the portion enclosed by the dashed line. Figure 6 This is an enlarged view showing the first core plate 60, which consists of... Figure 2 The diagram shows the portion enclosed by the dashed line. Figure 7 This is a magnified view showing the second core plate 70, which consists of... Figure 2 The diagram shows the portion enclosed by the dashed line. Figures 5 to 7In the illustration, the positions of the magnet 22 relative to the through holes 51, 61, and 71 when the magnet 22 is inserted into the magnet insertion hole 24 are shown with dashed lines. Additionally, in Figures 5 to 7 In the diagram, the magnet insertion hole 24 is shown with a slash for illustration.

[0049] like Figure 5 As shown, when the basic core plate 50 is viewed along its axial direction, the through hole 51 of the basic core plate 50 has a shape that is longer in one direction. In the basic core plate 50, the inner surface 51a, which is located radially inward among a pair of inner surfaces extending along the length direction of the through hole 51, does not contact the magnet 22. Figure 4 In the diagram, the radial position of the inner surface 51a is shown by P1.

[0050] like Figure 6 As shown, when the first core plate 60 is viewed along its axial direction, the through hole 61 of the first core plate 60 has a shape that is longer in one direction. The first core plate 60 has: a protrusion 62 that protrudes toward the interior of the through hole 61 and contacts the magnet 22; and a pair of slits 64 located on both sides of the base end 63 of the protrusion 62. The protrusion 62 protrudes radially inward toward the interior of the through hole 61 relative to the through hole 61. Furthermore, for the sake of explanation, in the first core plate 60, the portion of the inner surface of the through hole 61 that extends linearly in the radial direction of the through hole 61, excluding the protrusion 62, is referred to as the inner surface 61a. The radial position of the inner surface 61a coincides with the radial position P1 of the inner surface 51a of the basic core plate 50.

[0051] A pair of slits 64 extend radially. That is, the pair of slits 64 extend in the direction in which the protrusion 62 protrudes relative to the base end portion 63 of the protrusion 62. The portion sandwiched by the pair of slits 64 constitutes a part of the protrusion 62. Thus, the protrusion 62 can deform along the thickness direction of the first core plate 60 at the radial position P2 of the radially innermost end portion of the pair of slits 64. That is, the protrusion 62 can deform along the thickness direction of the first core plate 60 at the base end portion 63 sandwiched by the radially inner ends of the pair of slits 64.

[0052] like Figure 4 As shown, with the magnet 22 inserted into the magnet insertion hole 24, the protrusion 62 bends at its base end 63 in the thickness direction of the first core plate 60. The front end 65 of the protrusion 62 is located within the magnet insertion hole 24 on the side closer to the axis of the first core plate 60 than the base end 63 of the protrusion 62. The front end 65 of the protrusion 62 is held by the magnet 22 and the inner surface of the through hole 51 of the basic core plate 50.

[0053] like Figure 7As shown, when the second core plate 70 is viewed along the axial direction, the through hole 71 of the second core plate 70 has a shape that is longer in one direction. The second core plate 70 has a recess 72 that is recessed radially inward at the position where it overlaps with the protrusion 62 of the first core plate 60 when viewed along the axial direction. When the second core plate 70 is viewed from the axial direction, the recess 72 is recessed in the direction opposite to the protruding direction of the protrusion 62. The radial position of one of the pair of inner surfaces 71a extending along the length direction of the through hole 71 coincides with the radial position P1 of the inner surface 51a of the basic core plate 50.

[0054] like Figure 4 As shown, when the rotor core 21 is viewed along the axial direction, the radial position P3 of the radially innermost radially inner surface 72a of the inner surface constituting the recess 72 coincides with the radial position P2 of the radially inner ends of the pair of slits 64 of the first core plate 60. The recessed side surfaces 72b extending on both sides of the radially inner surface 72a of the inner surface constituting the recess 72 overlap with the slits 64 of the first core plate 60 when the rotor core 21 is viewed along the axial direction. Thus, when the front end portion 65 of the protrusion 62 of the first core plate 60 deforms in the insertion direction of the magnet 22, the middle portion of the protrusion 62 located between the base end portion 63 and the front end portion 65 is housed within the recess 72 of the second core plate 70.

[0055] In this way, by stacking the second core plate 70 adjacent to each other on one side of the first core plate 60 in the axial direction, the front end 65 of the protrusion 62 of the first core plate 60 can be easily bent in the axial direction within the magnet insertion hole 24. Thus, the front end 65 of the protrusion 62 of the first core plate 60, bent in the axial direction within the magnet insertion hole 24, can be held by the magnet 22 and the inner surface of the through hole 51 of the basic core plate 50.

[0056] The rotor 2 having the above structure includes: a cylindrical rotor core 21 having a plurality of core plates 25 stacked along the thickness direction and a magnet insertion hole 24 extending along the axial direction; and a magnet 22 inserted into the magnet insertion hole 24. At least one of the plurality of core plates 25 is a first core plate 60 having a protrusion 62 protruding toward the interior of the magnet insertion hole 24 of the rotor core 21 and contacting the magnet 22. The front end portion 65 of the protrusion 62 is located within the magnet insertion hole 24 closer to the direction in which the magnet 22 is inserted into the magnet insertion hole 24 than the base end portion 63 of the protrusion 62, i.e., the magnet insertion direction, and is sandwiched between the magnet 22 and an inner surface of the magnet insertion hole 24 formed by a core plate different from the first core plate 60 having the protrusion 62.

[0057] For example, a known structure for holding a magnet within a magnet insertion hole includes a protrusion whose tip faces inward toward the interior of the insertion hole and contacts the magnet inside the hole, thus holding the magnet within the insertion hole by the elastic restoring force of the protrusion. In such a structure, the protrusion repeatedly deforms when centrifugal force is applied to the magnet due to the rotation of the rotor. This can potentially reduce the strength of the protrusion.

[0058] In contrast, in the rotor 2 of this embodiment, the front end 65 of the protrusion 62 of the first core plate 60 is located in the magnet insertion hole 24 at a position closer to the magnet insertion direction than the base end 63 of the first core plate 60, and is sandwiched by the magnet 22 and the inner surface of the magnet insertion hole 24, which is made of a basic core plate 50 different from the first core plate 60. Therefore, the magnet 22 and the protrusion 62 will not move within the magnet insertion hole 24. Thus, even when centrifugal force is applied to the magnet 22 due to the rotation of the rotor 2, the reduction in strength of the protrusion 62 can be suppressed. Therefore, the reduction in the holding force of the magnet 22 within the magnet insertion hole 24 can be suppressed.

[0059] Furthermore, in the rotor 2 of this embodiment, since the protrusion 62 is held within the magnet insertion hole 24 by the magnet 22 and the inner surface of the magnet insertion hole 24, the holding force of the magnet 22 within the magnet insertion hole 24 can be increased compared to the conventional structure described above. Therefore, a rotor 2 with a large holding force of the magnet 22 can be provided.

[0060] Furthermore, in this embodiment, the rotor core 21 has a second core plate 70 that is stacked adjacent to the first core plate 60 in the aforementioned magnet insertion direction. When the rotor core 21 is viewed along the axial direction, the second core plate 70 has a recess 72 at a position where it overlaps with the protrusion 62 of the first core plate 60. This recess 72 is recessed in a direction opposite to the protrusion direction of the protrusion 62 and accommodates at least a portion of the protrusion 62 of the first core plate 60.

[0061] Therefore, with the magnet 22 inserted into the magnet insertion hole 24, the middle portion of the protrusion 62 of the first core plate 60, located between the base end portion 63 and the front end portion 65, is housed within the recess 72 of the second core plate 70. Thus, as... Figure 4As shown, when the rotor core 21 is viewed in a cross-section including the central axis P, the aforementioned middle portion of the protrusion 62 can be bent into an arc shape. Therefore, compared to the case where the protrusion 62 is bent at a right angle, the bending stress generated at the base end 63 can be reduced. As a result, the protrusion 62 can be bent more reliably within the magnet insertion hole 24 along the magnet insertion direction, and the front end 65 of the protrusion 62 can be more reliably clamped by the magnet 22 and the inner surface of the magnet insertion hole 24. Thus, a structure that can more reliably retain the magnet 22 within the magnet insertion hole 24 can be achieved.

[0062] In addition, the first core plate 60 has a pair of slits 64 located on both sides of the base end 63 of the protrusion 62.

[0063] Therefore, the protrusion 62 can be easily bent along the thickness direction of the first core plate 60 without deforming other parts of the first core plate 60. Thus, the front end 65 of the protrusion 62 can be more reliably held within the magnet insertion hole 24 using the magnet 22 and the inner surface of the magnet insertion hole 24. This allows for a structure that more reliably retains the magnet 22 within the magnet insertion hole 24.

[0064] In this embodiment, the rotor core 21 is composed of multiple stacked groups 27, each including a first core plate 60. That is, in this embodiment, the rotor core 21 has multiple first core plates 60. The front ends 65 of the protrusions 62 of the multiple first core plates 60 are located in the magnet insertion hole 24 at positions closer to the magnet insertion direction than the base ends 63 of the first core plates 60, and are sandwiched between the magnet 22 and the inner surface of the magnet insertion hole 24.

[0065] Therefore, in the rotor 2, the magnet 22 can be held within the magnet insertion hole 24 by multiple protrusions 62. Thus, compared to the case where the rotor core 21 has only one protrusion 62, the magnet 22 can be held with a greater holding force.

[0066] (Manufacturing method of rotor)

[0067] Next refer to Figure 8 An exemplary method for manufacturing the rotor 2 configured as described above is explained. The method for manufacturing the rotor 2 includes a core plate stacking process S1 and a magnet insertion process S2.

[0068] In the core plate stacking process S1, a cylindrical rotor core 21 with a magnet insertion hole 24 extending along the axial direction is obtained by stacking a basic core plate 50, a first core plate 60, and a second core plate 70 in a predetermined order along the thickness direction. Specifically, in this embodiment, multiple stacking groups 27 are stacked, each stacking a first core plate 60, a second core plate 70, and multiple basic core plates 50 sequentially from one side of the axial direction toward the other. When the core plate stacking process S1 is completed, multiple protrusions 62 protrude inward within the magnet insertion hole 24 of the rotor core 21. Additionally, recesses 72 are located on the axial direction side of the protrusions 62.

[0069] In the magnet insertion process S2, the magnet 22 is inserted into the magnet insertion hole 24. When the magnet 22 is inserted into the magnet insertion hole 24, the front end of the magnet 22 pushes against the protrusion 62. As a result, the front end 65 of the protrusion 62 is pressed in the magnet insertion direction, and the front end of the protrusion 62 bends. At this time, the middle portion of the protrusion 62 located between the base end 63 and the front end 65 is housed in the recess 72 located on one side of the axial direction of the protrusion 62. Furthermore, by pushing the magnet 22 into the magnet insertion hole 24, the front end 65 of the protrusion 62 is clamped between the magnet 22 and the inner surface of the magnet insertion hole 24.

[0070] Through the above process, a rotor 2 can be obtained in which the front end 65 of the protrusion 62 of the first core plate 60 is located in the magnet insertion hole 24 on the side closer to the axial direction than the base end 63 of the first core plate 60 and is sandwiched between the magnet 22 and the inner surface of the magnet insertion hole 24.

[0071] That is, the method for manufacturing the rotor 2 includes: a core plate stacking process S1, in which multiple core plates 25 are stacked along the thickness direction to obtain a cylindrical rotor core 21 having a magnet insertion hole 24 extending along the axial direction; and a magnet insertion process S2, in which a magnet 22 is inserted into the magnet insertion hole 24 of the rotor core 21. In the magnet insertion process S2, by inserting the magnet 22 into the magnet insertion hole 24, the front end of the protrusion 62 is positioned in the insertion direction of the magnet 22 by means of the magnet 22 so that the base end of the protrusion 62 is located in the insertion direction of the magnet 22, and the front end 65 of the protrusion 62 is sandwiched between the magnet 22 and the inner surface of the magnet insertion hole 24.

[0072] Therefore, it is possible to manufacture a rotor 2 in which a portion of a plurality of core plates 25 are sandwiched between the magnet 22 and the inner surface of the magnet insertion hole 24. Thus, it is possible to provide a method for manufacturing a rotor 2 that suppresses the reduction of the holding force on the magnet 22.

[0073] In addition, the motor 1 of this embodiment has: a rotor 2 having the above-described structure; and a stator 3 having a stator coil 36 and a stator core 31.

[0074] Thus, a motor 1 is provided that has a rotor 2 that suppresses the reduction of the holding force on the magnet 22.

[0075] (A variation of Implementation Method 1)

[0076] Next, refer to Figure 9 An exemplary modification of Embodiment 1 will be described below. In the rotor 102 of this modification, the structure of the first core plate 160 constituting the rotor core 121 is different from that of the first core plate 60 in Embodiment 1. All other structures are the same as in Embodiment 1. Hereinafter, the same reference numerals will be used to denote structures identical to those in Embodiment 1, and descriptions will be omitted.

[0077] like Figure 9 As shown, the first core plate 160 has: a protrusion 162 that protrudes toward the interior of the magnet insertion hole 24 and contacts the magnet 22; and a pair of slits positioned by clamping the base end 163 of the protrusion 162. An illustration of the pair of slits of the first core plate 160 is omitted. The structure of the pair of slits is the same as that of the pair of slits 64 of the first core plate 60 in Embodiment 1.

[0078] The front end portion 165 of the protrusion 162 has a protrusion 166. The protrusion 166 is located on the side of the protrusion 162 opposite to the magnet 22. When the protrusion 162 is sandwiched between the magnet 22 and the inner surface of the magnet insertion hole 24, the protrusion 166 contacts the magnet 22. As a result, the contact area between the protrusion 162 and the magnet 22 is reduced.

[0079] That is, in the rotor 102 of this embodiment, the protrusion 162 of the first core plate 160 has a protrusion 166 protruding toward the magnet 22 at the front end 165 opposite to the magnet 22. When the front end 165 of the protrusion 162 is located in the magnet insertion direction, which is closer to the base end 163 of the first core plate 160, and is sandwiched between the magnet 22 and the inner surface of the magnet insertion hole 24, the protrusion 166 contacts the magnet 22.

[0080] This reduces the contact area between the protrusion 162 and the magnet 22. It also increases the surface pressure at the point of contact between the protrusion 162 and the magnet 22. Therefore, it improves the holding force of the protrusion 162 on the magnet 22. Furthermore, the protrusion 166 functions as a buffer against the magnet 22. Thus, the protrusion 162 enhances the holding force on the magnet 22 and prevents damage to the magnet 22.

[0081] (Implementation Method 2)

[0082] Next, refer to Figure 10 and Figure 11This section describes an exemplary embodiment 2. In the rotor 202 of this embodiment, the structure and stacking order of the plurality of core plates 225 constituting the rotor core 221 are different from those of the rotor core 21 in embodiment 1. All other structures are the same as in embodiment 1. Hereinafter, the same reference numerals will be used to denote structures identical to those in embodiment 1, and descriptions will be omitted.

[0083] In this embodiment, the rotor core 221 includes a basic core plate 50, a first core plate 60, a second core plate 70, and a third core plate 280. The magnet insertion hole 24 of the rotor core 221 includes a through hole 51 in the basic core plate 50, a through hole 61 in the first core plate 60, a through hole 71 in the second core plate 70, and a through hole 281 in the third core plate 280.

[0084] Figure 10 This is a magnified view of the third core plate 280 and... Figure 2 The portion enclosed by the dashed line is the same as the portion in the diagram. Figure 10 In the diagram, for illustration purposes, the position of magnet 22 relative to the through hole 281 when magnet 22 is inserted into magnet insertion hole 24 is shown with a dashed line. Additionally, for illustration purposes, in... Figure 10 In the middle, the magnet insertion hole 24 is shown with a diagonal line.

[0085] like Figure 10 As shown, when the third core plate 280 is viewed along the axial direction, the through hole 281 of the third core plate 280 has a shape that is longer in one direction. The through hole 281 of the third core plate 280 has the same size as the through hole 51 of the basic core plate 50. That is, in the third core plate 280, the inner surface 281a of a pair of inner surfaces extending along the length direction of the through hole 281, located radially inward, does not contact the magnet 22. The radial position of the inner surface 281a coincides with the radial position P1 of the inner surface 51a of the basic core plate 50.

[0086] The third core plate 280 has a pair of slits 282 and a deformable portion 283. The pair of slits 282 extend radially. That is, the pair of slits 282 extend in the direction in which the protrusion 62 protrudes relative to the base end 63 of the protrusion 62 of the first core plate 60. The portion sandwiched between the pair of slits 282 constitutes the deformable portion 283. Thus, the deformable portion 283 can deform along the thickness direction of the third core plate 280 at a radial position P4 located at the radially innermost radial end of the pair of slits 282. That is, the deformable portion 283 can deform along the thickness direction of the third core plate 280 at the position sandwiched between the radially inner ends of the pair of slits 282.

[0087] The radial length of a pair of slits 282 is the same as the radial length of a pair of slits 64 of the first core plate 60. That is, the radial position P4 of the radial inner end of the pair of slits 282 of the third core plate 280 is the same as the radial position P2 of the radial inner end of the pair of slits 64 of the first core plate 60.

[0088] Similarly, the radial position P4 of the radially inner end of a pair of slits 282 coincides with the radial position P3 of the radially inner side surface 72a of the recess 72 of the second core plate 70.

[0089] Figure 11 This is a diagram showing the stacking sequence of the plurality of core plates 225 constituting the rotor core 221. In the rotor core 221, the basic core plate 50, the first core plate 60, the second core plate 70 and the third core plate 280 are stacked in a predetermined order to form a stack group 227, and the plurality of stack groups 227 are stacked along the axial direction.

[0090] In this embodiment, the stacked assembly 227 includes a first core plate 60, two second core plates 70, a third core plate 280, and a plurality of basic core plates 50. Within the stacked assembly 227, the first core plate 60, the second core plate 70, the third core plate 280, the second core plate 70, and the plurality of basic core plates 50 are stacked sequentially from one side of the axial direction toward the other side of the axial direction.

[0091] According to this structure, with the magnet 22 inserted into the magnet insertion hole 24, a protrusion 62 of the first core plate 60 is housed in a recess 72 of the second core plate 70 located on one side of the first core plate 60 in the axial direction. With the magnet 22 inserted into the magnet insertion hole 24, the protrusion 62 of the first core plate 60 housed in the recess 72 of the second core plate 70 contacts a deformable portion 283 of the third core plate 280. The recess 72 of the second core plate 70 housing the deformable portion 283 of the third core plate 280 is located on one side of the deformable portion 283 in the axial direction. Therefore, the deformable portion 283 of the third core plate 280, which contacts the protrusion 62 of the first core plate 60, can also deform in the magnet insertion direction. In this way, the protrusion 62 of the first core plate 60 can deform in the magnet insertion direction without being significantly hindered by other core plates. Therefore, the protrusion 62 of the first core plate 60 can deform more in the thickness direction of the first core plate 60 compared with the structure of Embodiment 1.

[0092] That is, the rotor core 221 of this embodiment has: a plurality of second core plates 70, which are stacked relative to the first core plate 60 along the magnet insertion direction; and a third core plate 280, which has a structure other than the first core plate 60 and the second core plates 70. The third core plate 280 is located between the plurality of second core plates 70 that are adjacent in the stacking direction.

[0093] Therefore, multiple recesses 72 are located on the inner surface of the magnet insertion hole 24 and in the magnet insertion direction of the first core plate 60. This allows the protrusion 62 to bend more significantly. Consequently, the protrusion 62 can be bent more dramatically within the magnet insertion hole 24 along the magnet insertion direction. This allows the front end 65 of the protrusion 62 to be more reliably held using the magnet 22 and the inner surface of the magnet insertion hole 24. Therefore, a rotor 202 capable of suppressing a decrease in the holding force on the magnet 22 can be provided.

[0094] (Implementation Method 3)

[0095] Next, refer to Figure 12 and Figure 13 The following describes an exemplary embodiment 3. In the rotor 302 of this embodiment, the structure and stacking order of the plurality of core plates 325 constituting the rotor core 321 are different from those of the rotor cores 21 and 221 in embodiments 1 and 2. Other than this, the structure is the same as in embodiments 1 and 2. Hereinafter, the same symbols will be used to denote the same structures as in embodiments 1 and 2, and descriptions will be omitted.

[0096] In this embodiment, the rotor core 321 includes a basic core plate 50, a first core plate 60, a second core plate 70 on the other side of the axial direction, a third core plate 380, and a second core plate 390 on one side of the axial direction. The magnet insertion hole 24 of the rotor core 321 includes a through hole 51 in the basic core plate 50, a through hole 61 in the first core plate 60, a through hole 71 in the second core plate 70 on the other side of the axial direction, a through hole in the third core plate 380, and a through hole 391 in the second core plate 390 on one side of the axial direction.

[0097] The second core plate 70 on the other side of the axial direction has the same structure as the second core plate 70 in Embodiment 1. That is, the second core plate 70 on the other side of the axial direction has a recess 72 that is recessed radially inward at the position where it overlaps with the protrusion 62 of the first core plate 60. When the rotor core 21 is viewed along the axial direction, the radial position P3 of the radially innermost radially inner surface 72a of the inner surface constituting the recess 72 coincides with the radial position P2 of the radially inner ends of the pair of slits 64 of the first core plate 60.

[0098] The third core plate 380 has the same structure as the third core plate 280 of Embodiment 2. The third core plate 380 has a pair of slits and a deformable portion 383. The positions of the inner surfaces of the pair of slits are the same as those of the pair of slits 282 of the third core plate 280 of Embodiment 2. Illustrations of the pair of slits of the third core plate 380 are omitted.

[0099] The deformable portion 383 extends from a radial position P4 at the radially inner end of the pair of slits to the inner surface of the through hole 281. The deformable portion 383 is capable of deforming in the thickness direction of the third core plate 380 through the pair of slits.

[0100] The radial length of the aforementioned pair of slits is longer than the radial length of the slit 64 of the first core plate 60. That is, the radial position P4 of the radially inner end of the aforementioned pair of slits of the third core plate 380 is further radially away from the front end 65 of the protrusion 62 than the radial position P2 of the radially inner end of the pair of slits 64 of the first core plate 60.

[0101] Figure 12 This is an enlarged view showing the second core plate 390 on one side of the axial direction, and the... Figure 2 The diagram shows the same part enclosed by the dashed line. (Example) Figure 12 As shown, the second core plate 390 on one side of the axial direction has a through hole 391 and a recess 392. When the rotor core 321 is viewed along the axial direction, the position of the recess 392 on the inner surface 391a is the same as that of the second core plate 70 on the other side of the axial direction. When the rotor core 321 is viewed along the axial direction, the radial position P5 of the radially innermost radially inner surface 392a of the inner surface constituting the recess 392 relative to the front end 65 of the protrusion 62 of the first core plate 60 is radially further away from the front end 65 of the protrusion 62 of the first core plate 60 than the radial position P3 of the radially inner surface 72a of the second core plate 70 on the other side of the axial direction.

[0102] Figure 13 This diagram illustrates the stacking sequence of the multiple core plates 325 constituting the rotor core 321. The rotor core 321 consists of a basic core plate 50, a first core plate 60, a second core plate 70 on the other side of the axial direction, a third core plate 380, and a second core plate 390 on one side of the axial direction, stacked in a predetermined order as a stacking group 327. Multiple stacking groups 327 are stacked along the axial direction.

[0103] In this embodiment, the stacked assembly 327 includes a first core plate 60, a second core plate 70 on the other side of the axial direction, a third core plate 380, a second core plate 390 on one side of the axial direction, and a plurality of basic core plates 50. In the stacked assembly 327, the plurality of core plates 325 are stacked sequentially from the other side of the axial direction toward one side of the axial direction, including the first core plate 60, the second core plate 70 on the other side of the axial direction, the third core plate 380, the second core plate 390 on one side of the axial direction, and the plurality of basic core plates 50.

[0104] According to this structure, with the magnet 22 inserted into the magnet insertion hole 24, a protrusion 62 of the first core plate 60 is housed in a recess 72 of the second core plate 70 located on one side of the first core plate 60 in the axial direction. With the magnet 22 inserted into the magnet insertion hole 24, the protrusion 62 of the first core plate 60 housed in the recess 72 of the second core plate 70 contacts a deformable portion 383 of the third core plate 380. A recess 392 of the second core plate 390 housing the deformable portion 383 of the third core plate 380 is located on one side of the deformable portion 383 in the axial direction. Therefore, the deformable portion 383 of the third core plate 380, which contacts the protrusion 62 of the first core plate 60, can also deform in the magnet insertion direction. In this way, the protrusion 62 of the first core plate 60 can deform in the magnet insertion direction without being significantly hindered by other core plates. Therefore, compared with the structure of Embodiment 2, the protrusion 62 of the first core plate 60 can deform more in the thickness direction of the first core plate 60.

[0105] That is, in the rotor core 321 of this embodiment, when the rotor core 321 is viewed along the axial direction, among the plurality of second core plates 70, 390, the second core plate that is further away from the first core plate 60 in the stacking direction, the portion of the inner surface of the recess of the second core plate located on the side opposite to the protrusion direction of the protrusion 62 of the first core plate 60 is further away from the front end portion 65 of the protrusion 62 of the first core plate 60.

[0106] This allows for an increase in the size of the recessed portion in the middle section of the protrusion 62, located between the base end portion 63 and the front end portion 65. Consequently, the protrusion 62 can be easily bent, and the stress generated at the base end portion 63 of the protrusion 62 can be reduced. Therefore, the protrusion 62 can be bent more reliably within the magnet insertion hole 24 along the aforementioned magnet insertion direction. This allows for more reliable clamping of the front end portion 65 of the protrusion 62 using the magnet 22 and the inner surface of the magnet insertion hole 24. Therefore, a rotor 302 capable of suppressing a decrease in the holding force on the magnet can be provided.

[0107] (Other implementation methods)

[0108] The embodiments of the present invention have been described above, but these embodiments are merely examples for implementing the present invention. Therefore, the present invention is not limited to the above embodiments, and can be implemented by appropriately modifying the above embodiments without departing from its spirit.

[0109] In the above embodiments, the rotor cores 21, 221, and 321 are composed of multiple laminated groups 27, 227, and 327. However, the rotor core may also be composed of a single laminated group. The rotor core may also be composed of combinations of laminated groups 27, 227, and 327.

[0110] In the above embodiments, the first core plates 60 and 160 have a pair of slits. However, the first core plate may also not have a pair of slits.

[0111] In the above embodiments, the number of protrusions 62 and 162 protruding into the interior of each through hole in the first core plate 60 and 160 is two. However, the number of protrusions may be more than two.

[0112] In the above-described embodiment 1, the rotor core 21 includes a basic core plate 50, a first core plate 60, and a second core plate 70. However, the rotor core 21 may also not have a second core plate 70.

[0113] For example, such as Figure 14 As shown, the rotor core 421 of the rotor 402 can be formed by stacking first core plates 460 at predetermined intervals between a plurality of basic core plates 50. In this case, the dimension of the base end of the protrusion of the first core plate in the thickness direction can be smaller than the dimension of the other portions of the first core plate in the thickness direction. For example, as Figure 15 As shown, the first core plate 460 may also have a groove 460a on one side of the protrusion 462 in the axial direction when viewed from a cross-section including the central axis P of the rotor core 421. The thickness dimension L2 of the portion of the protrusion 462 of the first core plate 460 with the groove 460a is smaller than the thickness dimension L1 of the other portions. Furthermore, when viewed from a cross-section including the central axis of the rotor core, the first core plate may also have a groove on the other side of the protrusion in the axial direction. When viewed from a cross-section including the central axis of the rotor core, the first core plate may also have grooves on both the other side of the protrusion in the axial direction and one side in the axial direction. The protrusion of the first core plate may also have a thin-walled portion.

[0114] Therefore, the protrusion 462 is easily deformable in the thickness direction. Thus, the protrusion 462 can be easily bent. Therefore, the front end 465 of the protrusion 462 can be more reliably clamped using the inner surfaces of the magnet 22 and the magnet insertion hole 24. Therefore, a structure can be achieved that can suppress the reduction of the force holding the magnet 22 within the magnet insertion hole 24.

[0115] In the manufacturing method of rotor 2 according to Embodiment 1 above, when inserting magnet 22 into magnet insertion hole 24 in magnet insertion step S2, rotor 2 is manufactured by bending the protrusion 62 of first core plate 60. However, rotor can also be manufactured using first core plate with the front end of protrusion pre-bent.

[0116] Industrial availability

[0117] This invention can be used on the rotor of an IPM motor.

[0118] (Symbol Explanation)

[0119] 1. Motor (IPM motor)

[0120] Rotors 2, 102, 202, 302, and 402

[0121] 3 stators

[0122] 4. Outer shell

[0123] 20-axis

[0124] 21, 121, 221, 321, 421 rotor cores

[0125] 22 magnets

[0126] 24 magnet insertion holes

[0127] 25, 225, 325 iron core plates

[0128] 27, 227, 327 stacked groups

[0129] 31 stator core

[0130] 36 stator coils

[0131] 50 basic iron core plates

[0132] Through holes 51, 61, 71, 281, 391

[0133] Inner surfaces of 51a, 61a, 71a, 281a, and 391a

[0134] 60, 160, 460 First core plate

[0135] 62, 162, 462 protrusions

[0136] 63, 163 end

[0137] 64, 282 A pair of slits

[0138] 65, 165, 465 front end

[0139] 70, 390 Second Core Board

[0140] 72, 392 concave part

[0141] 72a, 392a radial inner surface

[0142] 72b Recessed side

[0143] 166 protrusions

[0144] 280, 380 third core plate

[0145] Deformation parts 283 and 383

[0146] 460a slot.

Claims

1. A rotor comprising: a cylindrical rotor core having a plurality of core plates laminated in a thickness direction and a magnet insertion hole extending in an axial direction; and a magnet inserted into the magnet insertion hole, wherein at least one of the plurality of core plates is a first core plate having a protruding portion protruding toward an inside of the magnet insertion hole of the rotor core and contacting the magnet, the first core plate has a pair of slits on both sides of a base end portion of the protruding portion, the protruding portion contacts a core plate other than the second core plate at a position closer to the magnet insertion hole than the base end portion of the protruding portion, a front end portion of the protruding portion is located in the magnet insertion hole at a position closer to a direction in which the magnet is inserted into the magnet insertion hole than the base end portion of the protruding portion, and is sandwiched by the magnet and an inner surface of the magnet insertion hole that is constituted by a core plate different from the first core plate having the protruding portion, and the front end portion contacts the magnet.

2. The rotor according to claim 1, wherein the rotor core has a plurality of the first core plates, and front end portions of the protruding portions of the plurality of the first core plates are respectively located in the magnet insertion hole at positions closer to the direction in which the magnet is inserted than base end portions of the first core plates, and are sandwiched by the magnet and the inner surface of the magnet insertion hole.

3. The rotor according to claim 1 or 2, wherein the protruding portion of the first core plate has a protruding portion protruding toward the magnet at a portion opposite to the front end portion of the protruding portion, and the protruding portion contacts the magnet in a state in which the front end portion of the protruding portion is located at a position closer to the direction in which the magnet is inserted than the base end portion of the first core plate, and is sandwiched by the magnet and the inner surface of the magnet insertion hole.

4. The rotor according to claim 1, wherein the first core plate has a pair of slits on both sides of the base end portion of the protruding portion.

5. The rotor according to claim 1, wherein a dimension of the base end portion of the protruding portion in the thickness direction is smaller than a dimension of other portions of the first core plate in the thickness direction.

6. The rotor according to claim 1, wherein the rotor core has a second core plate laminated adjacent to the first core plate in the direction in which the magnet is inserted, and the second core plate has a recessed portion recessed toward a direction opposite to a protruding direction of the protruding portion of the first core plate at a position overlapping the protruding portion of the first core plate when the rotor core is viewed in the axial direction, and accommodates at least a portion of the protruding portion of the first core plate.

7. The rotor according to claim 6, wherein the rotor core has: a plurality of the second core plates laminated on the first core plate in the direction in which the magnet is inserted; and a third core plate having a structure different from the first core plate and the second core plate. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The third core plate is located between the second core plates adjacent in the stacking direction among the plurality of second core plates.

8. The rotor according to claim 7, wherein When the rotor core is viewed in the axial direction, among the plurality of second core plates, the more distantly a second core plate is from the first core plate in the stacking direction, the more distantly a portion of an inner surface of the recess constituting the second core plate, which is located on a side opposite to a protruding direction of the protruding portion of the first core plate, is from a tip end portion of the protruding portion of the first core plate.

9. An IPM motor comprising: the rotor according to any one of claims 1 to 8; and a stator having a stator coil and a stator core.

10. A method of manufacturing a rotor of any one of claims 1 to 8, wherein, comprising: a core plate stacking process of obtaining a cylindrical rotor core having a magnet insertion hole extending in an axial direction by stacking the plurality of core plates in a thickness direction; and a magnet insertion process of inserting the magnet into the magnet insertion hole of the rotor core, in the magnet insertion process, by inserting the magnet into the magnet insertion hole, the tip end portion of the protruding portion is caused to be located at a position closer to an insertion direction of the magnet than a base end portion of the protruding portion by the magnet, and the tip end portion of the protruding portion is sandwiched between the magnet and an inner surface of the magnet insertion hole.

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