Rotor

Abstract

This rotor according to the present disclosure comprises: a rotor core that can rotate about a rotation axis; a plurality of magnets that are provided to the rotor core; a pair of end plates that are provided on both end sides in the axial direction of the rotor core; and a fixing member that fixes the rotor core, which is provided with the plurality of magnets, between the pair of end plates. The rotor core comprises a through-hole that extends in the axial direction of the rotor core and through which the fixing member passes. At least one of the pair of end plates comprises a communication hole which extends in the axial direction of the rotor core, through which the fixing member passes, and which is in communication with the through hole. The communication hole has: a fixing hole part that is larger than the through-hole and through which the fixing member passes; and an extension hole part that extends from the fixing hole part in a direction orthogonal to the axial direction of the rotor core. In a state in which the fixing member passes through the through-hole and the communication hole, the through-hole is filled with a resin via the communication hole.

Description

rotor

[0001] The present disclosure relates to a rotor provided in an electric motor or the like.

[0002] Conventionally, a rotor for an electric motor includes a rotor core rotatably mounted on a shaft, a plurality of permanent magnets mounted on the rotor core, a pair of plate-shaped end plates provided on both axial ends of the rotor core, and a fixing member that fixes the rotor core with the plurality of magnets between the pair of end plates. The fixing member is, for example, a bolt, and extends along the axial direction of the rotor core while passing through a through hole in the rotor core and the through holes in each end plate. When the fixing member is disposed along the axial direction of the rotor core, it serves to resist the centrifugal force acting on the rotor core when the rotor rotates.

[0003] In this configuration, if there is a gap between the fixing member and the inner circumferential surface of the through-hole of the rotor core, the rotor core may slide radially outward when the rotor rotates. If there is a gap between the fixing member and the inner circumferential surface of the through-hole of the rotor core, the fixing member cannot entirely support the force acting on the rotor core when the rotor rotates. Therefore, the above-mentioned gap reduces the strength of the rotor.

[0004] To prevent the rotor core from slipping during rotation of the rotor, the gap between the fixing member and the inner circumferential surface of the through hole of the rotor core is filled with a filler, such as a thermosetting resin.

[0005] Japanese Patent Application Laid-Open No. 2005-102460

[0006] Conventionally, a resin filler is filled into the through holes of the rotor core before the rotor core is fixed between a pair of end plates. Specifically, with a pair of end plates arranged on both axial ends of the rotor core and no fixing members arranged in the through holes of the rotor core, the filler is poured into the through holes of the rotor core via the through holes of one of the end plates.

[0007] When filling the rotor core with filler material before fixing it between a pair of end plates, if the viscosity of the filler material is low, the filler material may leak between the electromagnetic steel sheets that make up the rotor core or between the rotor core and the end plates. When filling the rotor core with filler material before fixing it between a pair of end plates, if the viscosity of the filler material is low, the filler material poured into the through holes of the rotor core may leak out of the rotor core through the through holes of the other end plate. Therefore, when filling the rotor core with filler material before fixing it between the pair of end plates, measures to prevent filler material leakage are required, which requires specialized equipment and increases costs. One example of a leakage prevention measure is sealing with a sealant.

[0008] When filling the rotor core with filler before fixing it between a pair of end plates, if the filler has a high viscosity, there is a risk that the filler will not be applied to the entire inner surface of the through hole of the rotor core. Therefore, applying the filler to the entire inner surface of the through hole of the rotor core will result in high costs. If the filler is not applied to the entire inner surface of the through hole of the rotor core, the gap between the fixing member and the through hole cannot be filled in its entirety, which will result in reduced reliability of the rotor.

[0009] It is conceivable to use a non-resin foam material as the filler, but foam fillers are expensive and have low strength.

[0010] A rotor core made of multiple electromagnetic steel plates is prone to distortion and will not assume the correct shape unless it is fixed with a fixing member. When a rotor core made of multiple electromagnetic steel plates is fixed with a fixing member after filling with filler, the rotor core may become distorted. Distortion of the rotor core may lead to a deterioration in the cogging torque of the motor. When a rotor core made of multiple electromagnetic steel plates is fixed with a fixing member after filling with filler, cracks may occur in the hardened filler. Cracking in the filler reduces the strength of the rotor.

[0011] In order to solve the above-mentioned problems, a rotor is desired in which, when the rotor core is fixed between a pair of end plates by the fixing members, resin can be filled into the gap between the fixing members and the rotor core.

[0012] The rotor of the present disclosure comprises a rotor core that can rotate around a rotation axis as the center of rotation, a plurality of magnets provided in the rotor core, a pair of end plates provided on both axial ends of the rotor core, and a fixing member that fixes the rotor core with the plurality of magnets provided between the pair of end plates, wherein the rotor core has a through hole extending along the axial direction of the rotor core and through which the fixing member passes, and at least one of the pair of end plates has a communicating hole extending along the axial direction of the rotor core and through which the fixing member passes and that communicates with the through hole, and the communicating hole has a fixing hole portion that is larger than the through hole and through which the fixing member passes, and an extension hole portion that extends from the fixing hole portion in a direction perpendicular to the axial direction of the rotor core, and when the fixing member passes through the through hole and the communicating hole, the through hole is filled with resin through the communicating hole.

[0013] FIG. 1 is a schematic perspective view showing a rotor according to a first embodiment of the present invention, showing a state before the rotor core is molded with resin. FIG. 2 is a schematic longitudinal sectional view of the rotor according to the first embodiment of the present invention, showing a state before the rotor core is molded with resin. FIG. 3 is a schematic top view showing a portion of an end plate of the rotor according to the first embodiment of the present invention. FIG. 4 is a schematic perspective view showing a rotor according to the first embodiment of the present invention, showing a state after the rotor core has been molded with resin. FIG. 5 is a schematic longitudinal sectional view of the rotor according to the first embodiment of the present invention, showing a state after the rotor core has been molded with resin. FIG. 6 is a schematic perspective view showing an enlarged portion of the rotor according to the first embodiment of the present invention, with a portion shown in cross section. FIG. 7 is a schematic longitudinal sectional view of the rotor according to the first embodiment of the present invention, showing a state after resin has been filled between the through holes of the rotor core and the fixing members before the rotor core is molded with resin. FIG. 8 is a schematic top view showing a portion of an end plate of a rotor according to a second embodiment of the present invention. FIG. 9 is a schematic top view showing a portion of an end plate of a rotor according to a first variant of the present invention. FIG. 10 is a schematic top view showing a portion of an end plate of a rotor according to a second variant of the present invention.

[0014] A rotor according to one aspect of the present disclosure will be described below with reference to the drawings. A rotor 1 according to a first embodiment will be described with reference to Figs. 1 to 7. The rotor 1 is used together with a stator (not shown) in an electric motor that powers a rotating device. The rotor 1 includes a rotor core 2, a plurality of magnets 3, a pair of end plates 4, 5, an attachment member 6, a fixing member 7, and a resin part 8. Note that the device in which the rotor 1 is used is not limited to an electric motor, and may be, for example, a generator.

[0015] The rotor core 2 is cylindrical and open at both ends in the axial direction J1. The rotor core 2 is made of a magnetic material. Typically, the rotor core 2 has a structure including a plurality of electromagnetic steel plates (not shown). The plurality of electromagnetic steel plates are stacked in the axial direction J1. As shown in FIG. 6 , the rotor core 2 includes an annular portion 9 and a plurality of protruding portions 10. The annular portion 9 is cylindrical and extends in the axial direction J1, and is open at both ends in the axial direction J1. The plurality of protruding portions 10 are provided on the annular portion 9 so as to protrude outward in the radial direction K1. Each protruding portion 10 has a substantially rectangular block shape and protrudes outward in the radial direction K1 from the outer circumferential surface of the annular portion 9. The tip surface of each protruding portion 10 has a curved surface that bulges outward in the radial direction K1. The plurality of protruding portions 10 are arranged circumferentially around the annular portion 9 at intervals. Grooves 11 that open outward in the radial direction K1 of the annular portion 9 are formed between adjacent protruding portions 10. In the axial direction J1, both ends of the groove portion 11 are open to the outside of the rotor core 2.

[0016] The rotor core 2 has a plurality of through holes 12 through which fixing members 7, which will be described later, pass. The through holes 12 extend along the axial direction J1 of the rotor core 2. Both ends of the through holes 12 in the axial direction J1 are open to the outside of the rotor core 2. In the first embodiment, the plurality of through holes 12 are each arranged in a protruding portion 10 of the rotor core 2. That is, each protruding portion 10 has a through hole 12 that passes through in the axial direction J1. The through holes 12 are arranged in the protruding portion 10 on the outside in the radial direction K1. The plurality of through holes 12 arranged in the rotor core 2 in this manner are aligned in the circumferential direction of the rotor core 2. In the illustrated example, the cross-sectional shape of the through holes 12 is circular, but this is not limited to this.

[0017] The rotor core 2 is rotatable around a rotation axis (rotating shaft) 13. The rotation axis 13 is, for example, cylindrical and extends in the axial direction J1. The rotation axis 13 is rotatably provided within a housing of an electric motor (not shown) via a bearing (not shown). The rotation axis 13 is rotatable around its own axis. The rotation axis 13 is provided integrally with the rotor core 2. Specifically, with the rotation axis 13 passing through an inner hole 14 of the rotor core 2, the rotor core 2 is fixed to the rotation axis 13 so as to be rotatable integrally with the rotation axis 13.

[0018] Each magnet 3 has a generally rectangular plate shape. The multiple magnets 3 are each provided in a groove 11 formed in the rotor core 2. Specifically, the magnet 3 is provided in the groove 11 with one plate surface of the magnet 3 facing one side surface of the groove 11 and the other plate surface of the magnet 3 facing the other side surface of the groove 11. That is, the magnet 3 is positioned in the groove 11 along the axial direction J1 and along the radial direction K1 of the rotor core 2. When the magnet 3 is provided in the groove 11, the magnet 3 is in contact with the bottom surface of the groove 11. In this manner, the multiple magnets 3 are provided radially in the rotor core 2.

[0019] In the axial direction J1 of the rotor core 2, the length of the magnet 3 is approximately the same as the length of the groove 11 in the axial direction J1. Therefore, when disposed in the groove 11, the magnet 3 does not protrude from both ends of the groove 11 in the axial direction J1. In the radial direction K1 of the rotor core 2, the length of the magnet 3 is approximately the same as the depth of the groove 11. As described above, the tip surface of the protrusion 10 has a curved shape that bulges outward in the radial direction K1 of the rotor core 2. Therefore, in the rotor core 2, a gap 15 extending along the axial direction J1 is formed between the tip surfaces of adjacent protrusions 10, 10. The gap 15 communicates with the groove 11 and opens outward in the radial direction K1 of the rotor core 2. In this manner, the multiple magnets 3 are provided in the rotor core 2.

[0020] The pair of end plates 4, 5 are provided at both ends of the rotor core 2 in the axial direction J1. In the first embodiment, the pair of end plates 4, 5 are disk-shaped. The outer diameter of the pair of end plates 4, 5 is smaller than the distance between the tips of the protrusions 10 corresponding to the radial direction K1. In the first embodiment, the pair of end plates 4, 5 are formed of a non-magnetic metal. For example, the pair of end plates 4, 5 are made of stainless steel. The disk-shaped end plates 4, 5 have a circular insertion hole 16 penetrating the center in the axial direction J1. The aforementioned rotating shaft 13 passes through this insertion hole 16. The pair of end plates 4, 5 have a plurality of communication holes 17 through which the fixing member 7 (described later) passes. The communication holes 17 extend along the axial direction J1 of the rotor core 2. Both ends of the communication hole 17 in the axial direction J1 open outward from the end plates 4, 5. In this way, the pair of end plates 4, 5 have a plurality of communication holes 17 penetrating in the axial direction J1. In the first embodiment, the communication holes 17 are arranged on the outer sides in the radial direction K1 in the end plates 4, 5. The multiple communication holes 17 arranged in the end plates 4, 5 in this manner are aligned in the circumferential direction of the end plates 4, 5.

[0021] The communicating hole 17 has a fixing hole portion 18 through which the fixing member 7 passes, and an extension hole portion 19 that communicates with the fixing hole portion 18. The fixing hole portion 18 is larger than the through hole 12 of the rotor core 2. In the illustrated example, the fixing hole portion 18 is circular. When the fixing hole portion 18 is circular, the diameter of the fixing hole portion 18 is larger than the diameter of the through hole 12 of the rotor core 2. The extension hole portion 19 extends from the fixing hole portion 18 in a direction perpendicular to the axial direction J1 of the rotor core 2. In the illustrated example, the extension hole portion 19 extends in the shape of an elongated hole from the fixing hole portion 18. The inner surface of the tip end of the extension hole portion 19 is approximately arc-shaped. The base end of the extension hole portion 19 opens into the fixing hole portion 18. Therefore, the interior of the extension hole portion 19 communicates with the interior of the fixing hole portion 18. The length in the width direction of the extended hole 19 is smaller than the diameter of the fixing hole 18. The shape of the fixing hole 18 is not limited to a circular shape, and the shape of the extended hole 19 is not limited to an elongated hole shape.

[0022] In the first embodiment, the extended hole portions 19 are disposed obliquely with respect to the radial direction K1 of the end plates 4, 5. Specifically, the extended hole portions 19 are disposed obliquely with respect to a line 1 that passes through the center of the fixing hole portion 18 and extends along the radial direction K1 of the end plates 4, 5. In the illustrated example, the extended hole portions 19 extend obliquely from the fixing hole portion 18 toward the outside of the end plates 4, 5 in the radial direction K1. The end plates 4, 5 have a first case in which the distance between the extended hole portions 19, 19 of a pair of adjacent communicating holes 17, 17 decreases as the distance moves outward in the radial direction K1, and a second case in which the distance between the extended hole portions 19, 19 of a pair of adjacent communicating holes 17, 17 increases as the distance moves outward in the radial direction K1. The first and second cases are disposed alternately along the circumferential direction of the end plates 4, 5. The extending hole portion 19 may extend obliquely from the fixing hole portion 18 toward the inside of the end plates 4, 5 in the radial direction K1.

[0023] The mounting member 6 is disk-shaped. The mounting member 6 has a circular insertion hole 20 penetrating in the axial direction J1 at its center. The mounting member 6 has a plurality of threaded holes 21 penetrating in the axial direction J1. The plurality of threaded holes 21 are arranged side by side in the circumferential direction of the mounting member 6. An internal thread is formed on the inner peripheral surface of each threaded hole 21. The outer diameter of the disk-shaped mounting member 6 is smaller than the outer diameters of the end plates 4, 5.

[0024] The fixing member 7 fixes the rotor core 2, on which the plurality of magnets 3 are provided, between the pair of end plates 4, 5. When fixing the rotor core 2 between the pair of end plates 4, 5, the fixing member 7 passes through the communication holes 17 in the pair of end plates 4, 5 and the through holes 12 in the rotor core 2. When the fixing member 7 passes through the through holes 12 in the rotor core 2, a gap 31 is formed between the fixing member 7 and the inner circumferential surface of the through holes 12. When the fixing member 7 passes through the communication holes 17 in the end plates 4, 5, gaps 32, 33 are formed between the fixing member 7 and the inner surface of the communication holes 17. In the first embodiment, the fixing member 7 is a bolt. When the fixing member 7 is a bolt, the nominal diameter of the threaded portion 22 of the fixing member 7 is smaller than the diameter of the through holes 12 in the rotor core 2 and the diameter of the fixing hole portions 18 of the communication holes 17 in the end plates 4, 5. Therefore, when the fixing member 7 penetrates the through hole 12 and the communicating hole 17, a gap 31 is formed between the threaded portion 22 of the fixing member 7 and the inner surface of the through hole 12, and gaps 32, 33 are formed between the threaded portion 22 of the fixing member 7 and the inner surface of the communicating hole 17.

[0025] As shown in Figure 2, with the magnets 3 disposed in the grooves 11, the rotor core 2 is fixed between the pair of end plates 4, 5 by the fixing member 7. Specifically, with one plate surface of one end plate 4 abutting one end surface of the rotor core 2 in the axial direction J1 and one plate surface of the other end plate 5 abutting the other end surface of the rotor core 2 in the axial direction J1, the threaded portion 22 of the fixing member 7 is screwed into the screw hole 21 of the mounting member 6 superimposed on the other plate surface of the other end plate 5, via the fixing hole portions 18 of the communication holes 17 of the pair of end plates 4, 5 and the through hole 12 of the rotor core 2. In this way, the pair of end plates 4, 5 are provided at both ends of the rotor core 2 in the axial direction J1. With the pair of end plates 4, 5 fixed to the rotor core 2, the rotating shaft 13 to which the rotor core 2 is fixed passes through the inner hole 14 of the rotor core 2, the insertion hole 16 of the end plates 4, 5, and the insertion hole 20 of the mounting member 6. As described above, the outer diameter of the end plates 4, 5 is smaller than the distance between the tips of the protrusions 10 corresponding to the radial direction K1 and is larger than the outer diameter of the mounting member 6. Therefore, when the pair of end plates 4, 5 are fixed to the rotor core 2, the tip portions of the faces on both ends of the protrusions 10 in the axial direction J1 and the outer peripheral edge of the other plate face of the other end plate 5 are exposed to the outside.

[0026] With the rotor core 2 fixed between the pair of end plates 4, 5, both ends of the groove 11 of the rotor core 2 in the axial direction J1 are closed by the pair of end plates 4, 5. As described above, the magnet 3 is housed in this groove 11. Therefore, the pair of end plates 4, 5 prevents the magnet 3 in the groove 11 from slipping out of the groove 11 in the axial direction J1. In the first embodiment, the thickness of the plate-shaped magnet 3 is smaller than the length of the groove 11 in the width direction. Therefore, gaps 34 are formed between one plate surface of the magnet 3 and one side surface of the groove 11, and between the other plate surface of the magnet 3 and the other side surface of the groove 11.

[0027] As described above, the pair of end plates 4, 5 are made of stainless steel to prevent magnetic leakage. Because stainless steel end plates 4, 5 have low strength, they may collapse when the fixing member 7 is tightened if a washer is not used. Therefore, when the rotor core 2 is fixed between the pair of end plates 4, 5, a disk-shaped washer 24 is provided between the head 23 of the fixing member 7 and one of the end plates 4. The outer diameter of the washer 24 is larger than the diameter of the fixing hole 18 of the communicating hole 17. However, the washer 24 does not entirely cover the extension hole 19 extending from the fixing hole 18. The tip of the extension hole 19 extends from the washer 24. Therefore, at least a portion of the extension hole 19 of one of the end plates 4 is positioned so as not to overlap the washer 24 provided between the head 23 of the fixing member 7 and one of the end plates 4 when viewed in the axial direction J1 of the rotor core 2.

[0028] When the rotor core 2 is fixed between the pair of end plates 4, 5, the tip of the extended hole 19 of the other end plate 5 extends from the mounting member 6. Therefore, at least a portion of the extended hole 19 of the other end plate 5 is positioned so as not to overlap with the mounting member 6 that is overlaid on the other end plate 5 when viewed in the axial direction J1 of the rotor core 2. Typically, at least a portion of the extended hole 19 of the other end plate 5 is positioned on the outer circumferential edge of the other end plate 5. As described above, the outer circumferential edge of the other end plate 5 is exposed to the outside.

[0029] When the rotor core 2 is fixed between the pair of end plates 4, 5, the fixing hole portions 18 of the communicating holes 17 correspond in the axial direction J1 to the through holes 12 of the rotor core 2. Typically, the fixing hole portions 18 of the communicating holes 17 are arranged on the same axis as the through holes 12 of the rotor core 2. Therefore, the communicating holes 17 of the pair of end plates 4, 5 communicate with the through holes 12 of the rotor core 2.

[0030] The through holes 12 of the rotor core 2 communicate with the communication holes 17 of one end plate 4. At least a portion of the extended hole portion 19 of one end plate 4 is positioned so as to avoid the washer 24. Therefore, the through holes 12 of the rotor core 2 communicate with the outside via the communication holes 17 of one end plate 4. The through holes 12 of the rotor core 2 communicate with the communication holes 17 of the other end plate 5. The extended hole portion 19 of the other end plate 5 is positioned so as to avoid the mounting member 6. Therefore, the through holes 12 of the rotor core 2 communicate with the outside via the communication holes 17 of the other end plate 5.

[0031] The resin portion 8 has a first resin portion 25, a second resin portion 26, a third resin portion 27, a fourth resin portion 28, a fifth resin portion 29, and a sixth resin portion 30. The first resin portion 25 is arranged on one end side in the axial direction J1 of the rotor core 2. In the first embodiment, the first resin portion 25 is substantially disk-shaped and arranged on one end side in the axial direction J1 of the rotor core 2 so as to cover the other plate surface of one end plate 4, the outer peripheral surface of one end plate 4, and the tip portion of the surface of the protrusion 10 on one end side in the axial direction J1. The first resin portion 25 covers the head 23 of the fixing member 7. The second resin portion 26 is arranged on the other end side in the axial direction J1 of the rotor core 2. In the first embodiment, the second resin portion 26 is substantially disk-shaped and is arranged on the other end side of the rotor core 2 in the axial direction J1 so as to cover the outer peripheral surface of the mounting member 6, the outer peripheral edge of the other plate surface of the other end plate 5, the outer peripheral surface of the other end plate 5, and a tip portion of the surface of the protrusion 10 on the other end side in the axial direction J1. The third resin portion 27 is arranged on the rotor core 2 so as to connect the first resin portion 25 and the second resin portion 26. In the first embodiment, the third resin portion 27 is arranged on the rotor core 2 so as to fill a portion of the gap 15 formed on the outside of the rotor core 2 excluding the tip side and a gap 34 between the magnet 3 and the groove 11. When the third resin portion 27 is arranged on the rotor core 2, the protrusion 10 protrudes outward in the radial direction K1 of the rotor core 2 beyond the third resin portion 27. The fourth resin portion 28 fills a gap 32 between the inner surface of the communication hole 17 of the one end plate 4 and the threaded portion 22 of the fixing member 7. The fifth resin portion 29 fills a gap 33 between the inner surface of the communication hole 17 of the other end plate 5 and the threaded portion 22 of the fixing member 7. The sixth resin portion 30 fills a gap 31 between the inner circumferential surface of the through hole 12 of the rotor core 2 and the threaded portion 22 of the fixing member 7.

[0032] The resin portion 8 is made of resin. Typically, the resin portion 8 is formed by, for example, insert molding. Specifically, molten resin is poured into a mold that houses the rotor core 2, which is provided with the pair of end plates 4, 5 and the plurality of magnets 3, and the resin is then hardened to form the resin portion 8 on the rotor core 2, which is provided with the pair of end plates 4, 5 and the plurality of magnets 3. In the first embodiment, the resin that forms the resin portion 8 is, for example, a low-viscosity epoxy resin.

[0033] When the rotor core 2 is molded with resin in this manner, the molten resin is poured into the communicating holes 17 of one end plate 4. The resin poured into the communicating holes 17 of one end plate 4 then hardens to form the fourth resin portion 28. Therefore, in the first embodiment, with the fixing member 7 passing through the through holes 12 and the communicating holes 17, the communicating holes 17 of one end plate 4 are filled with resin.

[0034] When the rotor core 2 is molded with resin, the molten resin is poured into the through hole 12 of the rotor core 2 via the communication hole 17 of one end plate 4. The resin poured into the through hole 12 of the rotor core 2 then hardens to form the sixth resin portion 30. Therefore, in the first embodiment, with the fixing member 7 passing through the through hole 12 and the communication hole 17, the through hole 12 is filled with resin via the communication hole 17.

[0035] When the rotor core 2 is molded with resin, the molten resin is poured from the communication hole 17 of one end plate 4 through the through hole 12 into the communication hole 17 of the other end plate 5. The resin poured into the communication hole 17 of the other end plate 5 then hardens to form the fifth resin portion 29. Therefore, in the first embodiment, with the fixing member 7 passing through the through hole 12 and the communication hole 17, the communication hole 17 of the other end plate 5 is filled with resin.

[0036] When the rotor core 2 is molded with resin, the molten resin is poured into the grooves 11 through the gaps 15 formed on the outside of the rotor core 2, and also into the gaps 15 formed on the outside of the rotor core 2. At this time, the molten resin is poured into the gaps 15 formed on the outside of the rotor core 2 excluding the tip ends thereof. Thereafter, the resin poured into the grooves 11 hardens, and the resin poured into the gaps 15 formed on the outside of the rotor core 2 hardens, thereby forming the third resin portion 27. As described above, when the molten resin is poured into the grooves 11, the molten resin also pours into the gaps 34 between the magnets 3 and the grooves 11. Thereafter, the resin poured into the gaps 34 between the magnets 3 and the grooves 11 hardens, thereby fixing the magnets 3 to the rotor core 2.

[0037] In the first embodiment, the through holes 12 are filled with resin when the rotor core 2 is molded with resin. However, the through holes 12 may be filled with resin before the rotor core 2 is molded with resin. In this case, as shown in FIG. 7 , the fourth resin portion 28, the fifth resin portion 29, and the sixth resin portion 30 are formed before the rotor core 2 is molded with resin. When forming the fourth resin portion 28, molten resin is poured from a nozzle, for example, into the communication hole 17 of one end plate 4. When forming the sixth resin portion 30, molten resin is poured from a nozzle through the communication hole 17 of one end plate 4 and into the through hole 12 of the rotor core 2. When forming the fifth resin portion 29, molten resin is poured from a nozzle through the communication hole 17 of one end plate 4 and the through hole 12 of the rotor core 2, in that order, into the communication hole 17 of the other end plate 5.

[0038] However, the conventional rotor differs from the first embodiment in the configuration of the through holes formed in the pair of end plates. Therefore, in the conventional rotor, resin cannot be filled into the rotor's through holes when the fixing member passes through the rotor's through holes and the pair of end plates. Therefore, in the conventional rotor, resin is filled into the through holes via the through holes before the fixing member is installed. In the conventional rotor, when filling the through holes with resin, the electromagnetic steel sheets constituting the rotor core are not fixed to each other, and the rotor core is not fixed to the end plates. This means that resin may leak from gaps between the electromagnetic steel sheets or between the rotor core and the end plates. Therefore, in the conventional rotor, specialized equipment is required to prevent resin leakage when filling the through holes, resulting in high manufacturing costs.

[0039] In contrast, in the rotor 1 of the first embodiment, resin can be filled into the through hole 12 via the communication hole 17 with the fixing member 7 passing through the through hole 12 and the communication hole 17. Therefore, the rotor 1 of the first embodiment can be easily manufactured because there is no need to use equipment to prevent resin leakage when filling the through hole 12 with resin. The rotor 1 of the first embodiment can reduce manufacturing costs.

[0040] In conventional rotors, when the rotor core is made up of multiple electromagnetic steel plates and is fixed with fixing members after filling with resin, there is a risk that the rotor core may be fixed between the pair of end plates in a distorted state. In contrast, in the rotor 1 of the first embodiment, resin is filled into the through holes 12 of the rotor core 2 while the rotor core 2 is fixed between the pair of end plates 4, 5, so there is no risk of distortion of the rotor core 2. Therefore, the rotor 1 of the first embodiment can achieve a motor with high feed performance.

[0041] In the case of the rotor 1 of the first embodiment, the communication holes 17 are provided in both of the pair of end plates 4, 5. Therefore, according to the rotor 1 of the first embodiment, a flow path for the resin can be secured as shown by the arrows in Figure 2, and therefore the filling efficiency when filling the rotor core 2 with resin can be improved.

[0042] In the rotor 1 of the first embodiment, when resin is molded into the rotor core 2, the grooves 11 in which the magnets 3 are housed are filled with resin, and the through holes 12 through which the fixing members 7 pass are also filled with resin. Therefore, the resin that molds the outside of the rotor core 2 provided with the pair of end plates 4, 5, the resin that fills the through holes 12, and the resin that fixes the multiple magnets 3 to the rotor core 2 are a common resin and are connected together. Here, the resin that molds the outside of the rotor core 2 refers to the resin that constitutes the first resin portion 25, the resin that constitutes the second resin portion 26, and the resin that constitutes the third resin portion 27 excluding the portion that is housed in the grooves 11. Therefore, according to the rotor 1 of the first embodiment, the first resin portion 25, the second resin portion 26, the third resin portion 27, the fourth resin portion 28, the fifth resin portion 29, and the sixth resin portion 30 are integrally formed, so that filling the through holes 12 with resin, fixing the magnets 3 to the rotor core 2, and molding the outside of the rotor core 2 can be performed all at once. This allows the number of steps required to manufacture the rotor 1 to be reduced.

[0043] In the rotor 1 of the first embodiment, the extension hole 19 extends obliquely with respect to the radial direction K1 from the fixing hole 18. Therefore, according to the rotor 1 of the first embodiment, when centrifugal force is applied to the rotor core 2 during rotation of the rotor 1, the contact area when the fixing member 7 comes into contact with the outer portion of the inner circumferential surface of the fixing hole 18 in the radial direction K1 via the sixth resin portion 30 is increased. This allows the strength of the rotor 1 to be improved.

[0044] Next, a rotor 1a according to a second embodiment of the present invention will be described with reference to FIG. 8 . Components having the same reference numerals as those in the first embodiment function in the same manner, and therefore may not be described below. The rotor 1a according to the second embodiment differs from the first embodiment in the configuration of the communication holes 17 formed in the pair of end plates 4, 5. Specifically, the extension holes 19 extend from the fixing holes 18 along the radial direction K1 of the end plates 4, 5 (parallel to the radial direction K1). In the illustrated example, the extension holes 19 extend from the fixing holes 18 toward the outside of the end plates 4, 5 in the radial direction K1. The extension holes 19 are elongated holes extending along the radial direction K1 of the end plates 4, 5. Here, only the end plate 4, one of the pair of end plates 4, 5, will be described; however, the other end plate 5 also has a communication hole 17 similar to that of the other end plate 4.

[0045] In the rotor 1a of the second embodiment, the extended holes 19 extend from the fixing holes 18 along the radial direction K1 of the end plates 4, 5, so the distance between adjacent extended holes 19, 19 is substantially constant. Therefore, according to the rotor 1a of the second embodiment, no weak portions are formed in the end plates 4, 5, and the strength of the rotor 1a can be improved.

[0046] According to at least one of the embodiments described above, with the fixing members 7 passing through the through holes 12 and the communicating holes 17, it is possible to fill the through holes 12 with resin via the communicating holes 17. Therefore, it is possible to provide the rotors 1, 1a in which, with the rotor core 2 fixed between the pair of end plates 4, 5 by the fixing members 7, it is possible to fill the gaps 31 between the fixing members 7 and the rotor core 2 with resin.

[0047] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments.

[0048] For example, the configuration of the communication holes 17 may be the configuration shown in Fig. 9 or the configuration shown in Fig. 10. Here, only one end plate 4 of the pair of end plates 4, 5 will be described, but the other end plate 5 also has communication holes 17 similar to those of the one end plate 4.

[0049] In the rotor 1b of Modification 1 shown in FIG. 9 , the extension hole 19 extends from the fixing hole 18 along the circumferential direction of the end plates 4 and 5. In the rotor 1b of Modification 1 shown in FIG. 9 , the extension hole 19 extends from the fixing hole 18 along the circumferential direction of the end plates 4 and 5 and then extends in the radial direction K1 of the end plates 4 and 5. With this configuration, when centrifugal force is applied to the rotor core 2 during rotation of the rotor 1b, the rotor 1b of Modification 1 increases the contact area when the fixing member 7 contacts the outer portion of the inner circumferential surface of the fixing hole 18 in the radial direction K1 via the sixth resin portion 30. This increases the strength of the rotor 1b. The rotor 1b of Modification 1 is otherwise similar in configuration to the rotor 1 of the first embodiment. In the illustrated example, the end plates 4, 5 have an extended hole portion 19 extending along the circumferential direction of the end plates 4, 5, and an extended hole portion 19 extending along the circumferential direction of the end plates 4, 5 and then extending in the radial direction K1 of the end plates 4, 5, but it is also possible to have either one of the extended hole portions 19.

[0050] In the rotor 1c of Modification 2 shown in FIG. 10 , the extension hole 19 extends from the fixing hole 18 along the radial direction K1 of the end plates 4 and 5. Specifically, the extension hole 19 extends from the fixing hole 18 toward the inside of the end plates 4 and 5 in the radial direction K1. The extension hole 19 opens into the insertion hole 16 of the end plates 4 and 5. With this configuration, when centrifugal force is applied to the rotor core 2 during rotation of the rotor 1c, the rotor 1c of Modification 2 increases the contact area when the fixing member 7 contacts the outer portion of the inner circumferential surface of the fixing hole 18 in the radial direction K1 via the sixth resin portion 30. This increases the strength of the rotor 1c. The rotor 1c of Modification 2 is otherwise similar in configuration to the rotor 1 of the first embodiment.

[0051] The rotors to which the rotors 1 and 1a of the above-described embodiments and the rotors to which the rotors 1b and 1c of the above-described modified examples are applied may be rotors of SPM (Surface Permanent Magnet) motors or rotors of IPM (Interior Permanent Magnet) motors.

[0052] In the rotors 1, 1a of the above-described embodiments and the rotors 1b, 1c of the above-described modifications, the communication holes 17 having the fixing holes 18 and the extended holes 19 are provided in both of the pair of end plates 4, 5, but they may be provided in either one of the pair of end plates 4, 5. In other words, the communication holes 17 having the fixing holes 18 and the extended holes 19 only need to be provided in at least one of the pair of end plates 4, 5.

[0053] The following supplementary notes are further disclosed regarding the above embodiment: (Supplementary Note 1) The rotor (1) includes a rotor core (2) rotatable about a rotation axis (13), a plurality of magnets (3) provided on the rotor core (2), a pair of end plates (4, 5) provided on both axial ends of the rotor core (2), and a fixing member (7) that fixes the rotor core (2) provided with the plurality of magnets (3) between the pair of end plates (4, 5). The rotor core (2) has a through hole (12) extending along the axial direction of the rotor core (2) and through which the fixing member (7) passes, and at least one of the pair of end plates (4, 5) has a communication hole (17) extending along the axial direction of the rotor core (2) and through which the fixing member (7) passes and which communicates with the through hole (12), the communication hole (17) having a fixing hole portion (18) larger than the through hole (12) and through which the fixing member (7) passes, and an extension hole portion (19) extending from the fixing hole portion (18) in a direction perpendicular to the axial direction of the rotor core (2). When the fixing member (7) passes through the through hole (12) and the communication hole (17), the through hole (12) is filled with resin via the communication hole (17). (Supplementary Note 2) In the rotor (1) of Supplementary Note 1, it is preferable that the pair of end plates (4, 5) are made of a non-magnetic metal, the fixing member (7) is a bolt, and at least a part of the extended hole portion (19) is arranged so as not to overlap a washer (24) provided between the head (23) of the fixing member (7) and the end plate (4) when viewed from the axial direction of the rotor core (2). (Supplementary Note 3) In the rotor (1) of Supplementary Note 1 or Supplementary Note 2, it is preferable that the extended hole portion (19) is arranged obliquely with respect to the radial direction of the end plates (4, 5). (Supplementary Note 4) In the rotor (1) of Supplementary Note 1 or Supplementary Note 2, it is preferable that the extended hole portion (19) is arranged so as to extend from the fixing hole portion (18) along the radial direction of the end plates (4, 5). (Supplementary Note 5) In the rotor (1) according to any one of Supplementary Note 1 to Supplementary Note 4, it is preferable that the communication holes (17) are provided in both of the pair of end plates (4, 5).(Appendix 6) In the rotor (1) of any of Appendices 1 to 5, it is preferable that the resin that molds the outside of the rotor core (2) provided with the pair of end plates (4, 5), the resin that fills the through holes (12), and the resin that fixes the multiple magnets (3) to the rotor core (2) are a common resin and are connected to each other.

[0054] REFERENCE SIGNS LIST 1 rotor 2 rotor core 3 magnet 4 end plate 5 end plate 7 fixing member 12 through hole 13 rotating shaft 17 communication hole 18 fixing hole 19 extension hole 23 head 24 washer

Claims

1. A rotor core that can rotate around the axis of rotation, Multiple magnets provided on the rotor core, A pair of end plates provided on both axial ends of the rotor core, The rotor core, on which the plurality of magnets are provided, is fixed by a fixing member that fixes it between the pair of end plates, The rotor core is provided with a through hole that extends along the axial direction of the rotor core and through which the fixing member passes, Of the pair of end plates, at least one is provided with a communication hole that extends along the axial direction of the rotor core and through which the fixing member passes and communicates with the through hole, The communication hole has a fixing hole portion that is larger than the through hole and through which the fixing member passes, and an extension hole portion that extends from the fixing hole portion in a direction perpendicular to the axial direction of the rotor core. A rotor in which the fixing member penetrates the through hole and the communication hole, and the through hole is filled with resin through the communication hole.

2. The pair of end plates are made of a non-magnetic metal. The aforementioned fixing member is a bolt, The rotor according to claim 1, wherein at least a portion of the extension hole is arranged so as not to overlap with a washer provided between the head of the fixing member and the end plate when viewed from the axial direction of the rotor core.

3. The rotor according to claim 1 or 2, wherein the extension hole is arranged obliquely to the radial direction of the end plate.

4. The rotor according to claim 1 or 2, wherein the extension hole is arranged to extend from the fixing hole along the radial direction of the end plate.

5. The rotor according to claim 1 or 2, wherein the communication holes are provided in both of the pair of end plates.

6. The rotor according to claim 1 or 2, wherein the resin used to mold the outside of the rotor core on which the pair of end plates are provided, the resin used to fill the through holes, and the resin used to fix the plurality of magnets to the rotor core are a common resin and are connected.