Rotor for rotating electrical machine and method for manufacturing the rotor

Abstract

To suitably hold a permanent magnet in a fixed state in a magnet storage hole.SOLUTION: A rotor 12 includes a rotor core 21, and a permanent magnet 22 stored in a plurality of magnet storage holes 24 provided on the rotor core 12. The magnet storage holes 24 are provided in a direction extending in a circumferential direction in the rotor core 21, and the permanent magnet 22 is fixed into the magnet storage holes 24 using a resin 28. The permanent magnet 22 is stored in the state where the resin 28 is interposed between an outer peripheral side core surface 25a as a core wall surface on the outer peripheral side in the magnet storage hole 24 and the permanent magnet 22, and between an inner peripheral side core surface 25b as a core wall surface on the inner peripheral side and the permanent magnet 22. The adhesive force of the resin 28 on the side of the outer peripheral side core surface is made to be higher than the adhesive force of the resin 28 on the side of the inner peripheral side core surface.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The disclosure in this specification relates to a rotor for a rotating electric machine and a method for manufacturing the rotor. [Background technology]

[0002] In an interior permanent magnet rotating electric machine, a rotor core is formed with multiple magnet accommodating holes, and permanent magnets are accommodated in the magnet accommodating holes. Also, a technique for fixing the permanent magnets in the magnet accommodating holes with resin is known (see, for example, Patent Document 1). Specifically, for example, a rotor core is provided with multiple magnet accommodating holes extending in the circumferential direction, and permanent magnets are adhesively fixed with resin on the radially inner and outer surfaces of the magnet accommodating holes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6813009 Summary of the Invention [Problem to be solved by the invention]

[0004] During use, rotating electrical machines are subject to thermal stresses on the rotor, causing repeated expansion and contraction of the resin within the magnet accommodating holes. The rotor is also subjected to vibrations and centrifugal forces. This can lead to peeling or damage to the resin within the magnet accommodating holes, raising concerns that such peeling could prevent the permanent magnets from remaining fixed.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a rotor for a rotating electric machine that can suitably hold a permanent magnet in a fixed state within a magnet accommodating hole, and a method for manufacturing the rotor. [Means for solving the problem]

[0006] The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. The objectives, features, and advantages disclosed in this specification will become more apparent by referring to the following detailed description and the accompanying drawings.

[0007] Method 1 is: A rotor for a rotating electric machine, comprising: a rotor core; and permanent magnets housed in a plurality of magnet housing holes provided in the rotor core, The magnet accommodating holes are provided in the rotor core so as to extend in a circumferential direction, and the permanent magnets are fixed in the magnet accommodating holes using resin, the permanent magnet is accommodated in the magnet accommodating hole with the resin interposed between it and an outer core surface, which is an outer core wall surface, and between it and an inner core surface, which is an inner core wall surface, The adhesive strength of the resin on the outer core surface side is higher than the adhesive strength of the resin on the inner core surface side.

[0008] In rotors of interior permanent magnet rotating electric machines, where the permanent magnets housed in the magnet accommodating holes are adhesively fixed with resin, it is conceivable that the resin may peel off or be damaged due to thermal stress, vibration, etc. that occurs during use of the rotating electric machine, and there is a concern that the fixed state of the permanent magnets may no longer be maintained due to this peeling, etc. In particular, if the resin peels off or is damaged on the radially outer side of the magnet accommodating holes due to thermal stress, vibration, etc., and also peels off or is damaged on the radially inner side due to centrifugal force generated as the rotor rotates, it is conceivable that the fixed state of the permanent magnets may no longer be maintained.

[0009] In this regard, resin is interposed between the permanent magnet and the outer core surface and between the permanent magnet and the inner core surface within the magnet accommodating hole of the rotor core, and the adhesive strength of the resin on the outer core surface side is stronger than that of the resin on the inner core surface side. In this case, due to the difference in adhesive strength between the outer core surface and the inner core surface, even if peeling of the resin occurs due to thermal stress, vibration, etc., the peeling occurs preferentially on the inner core surface side, while the fixed (adhered) state of the permanent magnet by the resin is maintained on the outer core surface side. Furthermore, when the rotating electric machine is in use, centrifugal force acts on the permanent magnet, but because the adhesive strength of the resin is stronger on the outer core surface side of the outer and inner core surfaces, the fixed state of the permanent magnet is maintained on the outer core surface side even in situations where centrifugal force is generated on the rotor. As a result, the permanent magnet can be suitably held fixed within the magnet accommodating hole.

[0010] A strong adhesive strength of the resin means that the permanent magnet is fixed strongly to the rotor core, and includes at least one of the following: no peeling of the resin at the interface between the rotor core and the resin, or the interface between the permanent magnet and the resin, and no damage to the resin between the rotor core and the permanent magnet. A strong adhesive strength of the resin also includes high tensile strength of the resin.

[0011] The resin (adhesive) used to secure the permanent magnets to the rotor core is not limited to a specific type, and can be selected appropriately depending on the intended use, including thermosetting resins such as epoxy, polyester, acrylic, urethane, and phenolic resins, and thermoplastic resins such as polypropylene, polybutylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polyether ether ketone, polyimide, polyamide, and polyacetal. Of course, resins containing fillers such as glass fiber, carbon fiber, and calcium carbonate may also be used to improve heat dissipation or strength. Furthermore, the resin may be in any form, such as a two-component mixture, one-component, pellets, powder, or foam adhesive sheet.

[0012] This configuration makes it possible to minimize the amount of resin used to secure the magnet, especially the amount of resin with a high degree of hardening. This reduces costs by reducing the amount of resin used, reduces the energy required to harden the resin, and reduces CO2 emissions.

[0013] Resin can be applied to the magnet fixing surface in a variety of ways, including injection molding, potting, pre-coating the magnet and then inserting it, pre-coating the core and then inserting the magnet, post-coating the magnet after inserting it and allowing it to penetrate, applying foam adhesive, or inserting a foam sheet. For resins that require mixing before application, you can choose methods such as mixing with a static mixer or dynamic mixer, or honeymoon bonding on the adhesive surface. For resins that require external energy to be applied to harden, various methods can be used, such as using a furnace, induction heater, electricity, electromagnetic wave heating, or light irradiation.

[0014] In a second aspect of the present invention, in the first aspect, the resin on the outer core surface side and the resin on the inner core surface side are made of resin materials that are different in at least one of material composition and compounding ratio.

[0015] According to the above configuration, it is possible to suitably realize a configuration in which the adhesive strength of the resin differs between the outer core surface side and the inner core surface side in the magnet accommodating hole of the rotor core.

[0016] In means 3, in means 1 or 2, the resin on the outer core surface side and the resin on the inner core surface side have different degrees of hardening, and the resin on the outer core surface side has a higher degree of hardening than the resin on the inner core surface side.

[0017] According to the above configuration, the resin on the outer core face side has a higher degree of hardening (reaction rate) than the resin on the inner core face side, thereby making it possible to preferably realize a configuration in which the adhesive strength of the resin differs between the outer core face side and the inner core face side.

[0018] In means 4, in any of means 1 to 3, the area of ​​the resin applied is different on the outer core face side and the inner core face side, and the area applied on the outer core face side is larger than that on the inner core face side.

[0019] According to the above configuration, by making the area of ​​resin application different between the outer core face side and the inner core face side, it is possible to preferably realize a configuration in which the adhesive strength of the resin is different between the outer core face side and the inner core face side.

[0020] In means 5, in any of means 1 to 4, an inner resin is interposed as the resin between the inner core surface and the permanent magnet within the magnet accommodating hole, and when the interface between the inner core surface and the inner resin is defined as a first interface and the interface between the permanent magnet and the inner resin is defined as a second interface, the adhesive strength to the inner resin at the first interface and the second interface are different from each other.

[0021] Because the adhesive strength of the inner resin is weak on the inner core surface side of the magnet accommodating hole, peeling of the inner resin is likely to occur. However, if peeling occurs randomly between the first interface on the inner core surface side and the second interface on the permanent magnet side, peeled pieces of resin will be generated inside the magnet accommodating hole, and there is a concern that they may enter the air gap between the rotor and the stator in a rotating electric machine. In this regard, because the adhesive strength to the inner resin is different between the first interface and the second interface, when peeling of the inner resin occurs, peeling will occur preferentially at either the first interface or the second interface. This makes it possible to suppress the generation of peeled pieces of resin due to peeling of the inner resin.

[0022] In a sixth aspect of the present invention, there is provided a rotor according to any one of the first to fifth aspects, which is disposed radially opposite to the stator of a rotating electric machine, and in the rotor core, the magnet accommodating holes are disposed on both sides of the magnetic pole center for each magnetic pole, and the opposing distance to the stator decreases from the magnetic pole center side toward the magnetic pole boundary side. SmallThe resin is provided with a pair of holes that are approximately V-shaped so that the adhesive strength of the resin is different between the magnetic pole center side and the opposite side on the inner core surface side, and the adhesive strength of the resin is stronger on the opposite side of the magnetic pole center.

[0023] The rotor core has magnet accommodating holes formed in a roughly V-shape. In other words, the permanent magnets are arranged in the magnet accommodating holes at an angle relative to the direction perpendicular to the radial direction. Therefore, when the rotor rotates, centrifugal force acts on the permanent magnets toward both ends of the V-shape. Taking this into consideration, the above-described configuration differs the adhesive strength of the resin on the inner core surface between the magnetic pole center and the opposite side, with the adhesive strength of the resin being stronger on the opposite side of the magnetic pole center. In this case, the resin remains unbroken in areas where centrifugal force acts on the permanent magnets, i.e., areas where the resin is subjected to a compressive force, thereby enabling the permanent magnets to be optimally fixed.

[0024] Measure 7 is: A method for manufacturing a rotor for a rotating electric machine, the method comprising: a rotor core; and permanent magnets housed in a plurality of magnet housing holes provided in the rotor core, the method comprising: The magnet accommodating holes are provided in the rotor core so as to extend in a circumferential direction, an assembling process in which resin is applied to an outer core surface, which is an outer core wall surface, and an inner core surface, which is an inner core wall surface, in the magnet accommodating hole, and the permanent magnet before magnetization is assembled in the magnet accommodating hole; a curing step of curing the resin in the magnet accommodating hole so that the adhesive strength of the resin on the outer core surface side is higher than the adhesive strength of the resin on the inner core surface side; a magnetizing step of applying a magnetizing magnetic field to the permanent magnet in a radial direction after the resin has hardened, thereby magnetizing the permanent magnet; The present invention is characterized by having the following:

[0025] According to the above manufacturing method, in the assembling step, the pre-magnetized permanent magnets are assembled integrally with the resin into the magnet accommodating holes of the rotor core, and in the subsequent hardening step, the resin hardens so that the adhesive strength of the resin on the outer core surface side is stronger than the adhesive strength of the resin on the inner core surface side. Furthermore, after the resin hardens, in the magnetizing step, a magnetizing magnetic field is applied radially to the permanent magnets to magnetize them.

[0026] During the magnetization process, a radial force is applied to the permanent magnet by a magnetizing magnetic field applied radially. However, because the adhesive strength of the resin is relatively strong on the outer core surface side and relatively weak on the inner core surface side, peeling or damage to the resin may occur on the inner core surface side, but peeling or damage to the resin is suppressed on the outer core surface side. Furthermore, because there is a difference in adhesive strength between the outer core surface and the inner core surface, even if peeling or damage to the resin occurs due to thermal stress or vibration during use of the rotating electric machine, such peeling or damage occurs preferentially on the inner core surface side, while the fixed state (adhered state) of the permanent magnet by the resin is maintained on the outer core surface side. Furthermore, during use of the rotating electric machine, centrifugal force of the rotor acts on the permanent magnet, but because the adhesive strength of the resin is stronger on the outer core surface side of the outer core surface and the inner core surface, the fixed state of the permanent magnet is maintained on the outer core surface side even in situations where centrifugal force is generated on the rotor. As a result, the permanent magnet can be held in a fixed state in the magnet accommodating hole.

[0027] In means 8, in means 7, the resin is made of a resin material that hardens with thermal energy or light energy, and in the hardening process, the amount of thermal energy or light energy is made different between the outer core face side and the inner core face side, so that the adhesive strength of the resin on the outer core face side is made stronger than the adhesive strength of the resin on the inner core face side.

[0028] According to the above manufacturing method, in a rotor using a thermosetting or photocurable resin, it is possible to preferably realize a configuration in which the adhesive strength of the resin is different on the outer core surface side and the inner core surface side.

[0029] In means 9, in the curing process of means 8, thermal energy or light energy is applied from the outer side of the rotor core to harden the resin on the outer core surface side and the resin on the inner core surface side.

[0030] When thermal energy or light energy is applied from the outer periphery of the rotor core, the amount of energy input is greater on the outer core surface side than on the inner core surface side, and the degree of hardening of the resin on the outer core surface side is higher than that on the inner core surface side, which makes it possible to preferably realize a configuration in which the adhesive strength of the resin differs between the outer core surface side and the inner core surface side.

[0031] In means 10, in means 9, before the hardening step, a stator having a stator winding is placed at a position radially opposite the rotor core, and in the hardening step, the resin on the outer core surface side and the resin on the inner core surface side are hardened by thermal energy generated by passing current through the stator winding.

[0032] According to the above manufacturing method, the stator windings are arranged at radially opposite positions on the rotor core, and the resin on the outer core surface side and the resin on the inner core surface side are hardened by the thermal energy generated by the current passing through the stator windings. In this case, the resin (adhesive) can be heat-hardened suitably in the series of manufacturing steps for the rotating electric machine without using a heating device. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. 3 is a process diagram showing a manufacturing procedure of a rotor. [Figure 6] FIG. [Figure 7] FIG. 10 is a cross-sectional view showing the configuration of a rotor according to a second embodiment. [Figure 8] FIG. 2 is a diagram showing the configuration of a longitudinal cross section of a rotor. [Figure 9] FIG. 10 is a diagram showing a modified example of the rotor. [Figure 10] FIG. 10 is a diagram showing a modified example of the rotor. DETAILED DESCRIPTION OF THE INVENTION

[0034] Hereinafter, embodiments will be described with reference to the drawings. The rotating electric machine in this embodiment is used, for example, as a vehicle power source. However, rotating electric machines can be widely used in industrial applications, marine applications, aircraft applications, home appliances, office automation equipment, gaming machines, and the like. In the following embodiments, identical or equivalent parts are designated by the same reference numerals in the drawings, and the same explanations for the parts with the same reference numerals are incorporated herein.

[0035] (First embodiment) A rotating electric machine 10 according to this embodiment is an inner rotor type (inner rotation type) polyphase AC motor, and its outline is shown in Figures 1 and 2. Figure 1 is a longitudinal cross-sectional view showing a longitudinal cross section of the rotating electric machine 10 in a direction along the rotating shaft 11, and Figure 2 is a transverse cross-sectional view showing a cross section of the rotor 12 and the stator 13 in a direction perpendicular to the rotating shaft 11. In the following description, the direction in which the rotating shaft 11 extends is referred to as the axial direction, the direction extending radially from the center of the rotating shaft 11 is referred to as the radial direction, and the direction extending circumferentially from the center of the rotating shaft 11 is referred to as the circumferential direction.

[0036] The rotating electric machine 10 includes a rotor 12 fixed to a rotating shaft 11, a stator 13 disposed surrounding the rotor 12, a housing 14 containing the rotor 12 and the stator 13, and a cover 15 fixed to one axial end of the housing 14. The rotor 12 and the stator 13 are coaxially arranged facing each other in the radial direction. The housing 14 is cylindrical with a bottom that opens to one axial end, and the cover 15 is attached to the open end with a plurality of bolts 16 as fasteners. Bearings 17 and 18 are provided in the housing 14 and the cover 15, and the rotating shaft 11 and the rotor 12 are rotatably supported by the bearings 17 and 18. A pulley 19 is attached to one end of the rotating shaft 11. Note that power transmission between the rotating shaft 11 and an external device is not limited to the pulley 19, and various forms are possible, such as a spline, a gear, or a keyed shaft.

[0037] 2, rotor 12 is configured as an interior permanent magnet rotor (IPM rotor) and has a rotor core 21 that rotates integrally with rotating shaft 11, and a plurality of permanent magnets 22 held by rotor core 21. A through hole 23 is formed at the axial center of rotor core 21, and rotating shaft 11 is fitted into through hole 23.

[0038] The rotor core 21 is made of a soft magnetic material and is constructed by stacking multiple electromagnetic steel plates in the axial direction and fixing them by caulking or the like. The rotor core 21 is provided with multiple magnet accommodating holes 24 at predetermined intervals in the circumferential direction, and each magnet accommodating hole 24 accommodates a permanent magnet 22. As a result, the permanent magnets 22 are arranged in a circumferential direction for each magnetic pole. In this embodiment, the rotor 12 is provided with eight magnetic poles (four pole pairs) with north and south poles arranged alternately in the circumferential direction. However, the number of poles is arbitrary.

[0039] The stator 13 has a substantially cylindrical stator core 31 made of a plurality of laminated electromagnetic steel sheets. The stator core 31 has a plurality of slots 32 that penetrate in the axial direction and are arranged at equal intervals in the circumferential direction. In the slots 32, for example, three-phase (U-phase, V-phase, and W-phase) stator windings 33 are wound.

[0040] Next, the magnet housing structure of the rotor core 21 will be described in detail with reference to Figures 3(a) and (b). Figure 3(a) shows a state in which the permanent magnets 22 are not housed in the magnet housing holes 24 of the rotor core 21, while Figure 3(b) shows a state in which the permanent magnets 22 are housed in the magnet housing holes 24 of the rotor core 21. Each of these figures shows one pole out of the multiple magnetic poles (e.g., a total of eight poles) of the rotating electric machine 10. In Figure 3(a), the magnetic pole center is the d-axis, and the magnetic pole boundary is the q-axis.

[0041] 3(a), a pair of magnet accommodating holes 24 is provided for each magnetic pole in rotor core 21. Each magnet accommodating hole 24 is provided on both sides of the d-axis, which is the center of the magnetic pole, and is shaped to be line-symmetrical with respect to the d-axis. Each magnet accommodating hole 24 has a first accommodating portion 25 provided so that its longitudinal direction extends in the circumferential direction, and a second accommodating portion 26 provided so that it extends radially from the d-axis side end of first accommodating portion 25.

[0042] Assuming that an orthogonal line perpendicular to the d-axis is drawn, the first housing portions 25 are provided in a direction inclined with respect to the orthogonal line. The first housing portions 25 on both sides of the d-axis have a distance between them and the stator 13 (i.e., a radial distance from the outer circumferential surface of the rotor core 21) that decreases from the d-axis side toward the q-axis side. Small The second accommodating portion 26 is provided as a pair of holes that are approximately V-shaped so that the d-axis is parallel to the axial direction of the rotor core 21. The second accommodating portion 26 has a portion that extends radially inward from the d-axis side end of the first accommodating portion 25 and a portion that extends circumferentially. A d-axis side bridge 27 that extends radially along the d-axis is provided between the second accommodating portions 26 that are lined up in the circumferential direction of the rotor core 21.

[0043] As shown in FIG. 3(b), a permanent magnet 22 is accommodated in the first accommodation portion 25 of each magnet accommodation hole 24 in a state of being adhesively fixed by a resin 28. The permanent magnet 22 has a rectangular cross section, and two magnet side surfaces 22a and 22b at the long-side portions in the cross section face two core wall surfaces 25a and 25b that are radially opposed in the first accommodation portion 25. Here, in the permanent magnet 22, the magnet side surface 22a on the outer side in the radial direction is referred to as the "outer peripheral side magnet surface 22a", and the magnet side surface 22b on the inner side in the radial direction is referred to as the "inner peripheral side magnet surface 22b". Further, in the first accommodation portion 25, the core wall surface 25a on the outer side in the radial direction is referred to as the "outer peripheral side core surface 25a", and the core wall surface 25b on the inner side in the radial direction is referred to as the "inner peripheral side core surface 25b". Each magnet surface 22a and 22b of the permanent magnet 22 is parallel to each other and is a magnetic flux action surface where the inflow and outflow of the magnet magnetic flux occur. Each core surface 25a and 25b of the first accommodation portion 25 is parallel to each other.

[0044] In a state where the permanent magnet 22 is accommodated in the magnet accommodation hole 24, a gap is formed between the q-axis side of the first accommodation portion 25 with respect to the permanent magnet 22 and the entire second accommodation portion 26. In the rotor core 21, the q-axis side end portion of the first accommodation portion 25 is close to the core outer peripheral surface, and an outer bridge 29 is formed between the q-axis side end portion of the first accommodation portion 25 and the core outer peripheral surface.

[0045] The radial width dimension W1 of the permanent magnet 22 (that is, the width dimension W1 between the magnet surfaces 22a and 22b) and the radial width dimension W2 of the first accommodation portion 25 (that is, the width dimension W2 between the core surfaces 25a and 25b) satisfy W1 < W2, and the permanent magnet 22 is accommodated in the first accommodation portion 25 with the resin 28 interposed between the outer peripheral side magnet surface 22a and the outer peripheral side core surface 25a and between the inner peripheral side magnet surface 22b and the inner peripheral side core surface 25b, respectively.

[0046] Note that each magnet accommodation hole 24 and the permanent magnet 22 are not limited to the above form, and include those arranged asymmetrically with respect to the d-axis. The shape of the permanent magnet 22 itself is not limited to that having a rectangular cross section, and includes those having an arc shape or other curved cross-sectional shapes.

[0047] In an embedded magnet rotor in which the permanent magnets housed in the magnet accommodating holes are adhesively fixed with resin, it is conceivable that the resin may peel off or be damaged due to thermal stress, vibration, etc. that occurs during use of the rotating electric machine, and there is a concern that the fixed state of the permanent magnets may no longer be maintained due to this peeling, etc. In particular, if peeling or damage to the resin occurs on the radially outer side of the magnet accommodating holes due to thermal stress, vibration, etc., and peeling or damage to the resin occurs on the radially inner side due to centrifugal force generated during rotation of the rotor, it is conceivable that the fixed state of the permanent magnets may no longer be maintained.

[0048] Therefore, in this embodiment, the adhesive strength of the resin 28A, which is the "outer resin 28A" on the outer core surface 25a side of the magnet accommodating hole 24 of the rotor 12, and the adhesive strength of the resin 28B, which is the "inner resin 28B" on the inner core surface 25b side, are different. In particular, the adhesive strength of the resin 28 is higher on the outer core surface 25a side than on the inner core surface 25b side. With respect to the permanent magnet 22, the adhesive strength of the resin 28 is higher on the radially outer side of the permanent magnet 22 (the outer circumferential side of the core) than on the radially inner side (the inner circumferential side of the core). This makes it possible to suitably maintain the fixed state of the permanent magnet 22 within the magnet accommodating hole 24. Details of this are described below.

[0049] In this embodiment, the outer resin 28A and the inner resin 28B are made of resin materials that differ in at least one of their material compositions and compounding ratios. Specifically, an epoxy adhesive is used as the outer resin 28A, and a cyanoacrylate adhesive is used as the inner resin 28B. In this case, the epoxy adhesive has a higher adhesive strength than the cyanoacrylate adhesive. Alternatively, resin materials that differ in at least one of their material compositions and compounding ratios can be used as appropriate, as long as the adhesive strength of the outer resin 28A and the inner resin 28B can be made different. The degree of cure is an index indicating the degree of cure of the resin and can be measured, for example, by Fourier transform infrared spectroscopy (FT-IR) or differential scanning calorimetry (DSC).

[0050] In addition to the above, it is also possible to differentiate the adhesive strengths of the resins 28A, 28B by using the following configuration. That is, it is possible to use an epoxy-based resin as the base for the outer resin 28A and the inner resin 28B, and to make the outer resin 28A of these resins 28A, 28B a resin that contains a large amount of filler such as glass material, which improves adhesive strength. Also, it is possible to use an epoxy-based resin as the base for the outer resin 28A and the inner resin 28B, and to make the outer resin 28A of these resins 28A, 28B a resin that contains a large amount of hardener, which promotes the hardening reaction.

[0051] As described above, the adhesive strength of the resins 28A, 28B is different between the outer core surface 25a side and the inner core surface 25b side, so that even if peeling or the like of the resin occurs due to expansion and contraction of the resin, the peeling or the like occurs preferentially on the inner core surface 25b side. Therefore, the fixed state (adhered state) of the permanent magnet 22 by the resin is maintained on the outer core surface 25a side.

[0052] 4(a) and 4(b) are diagrams for explaining the forces acting on the permanent magnets 22 in the rotor 12. In Fig. 4(a), F1 denotes the force (electromagnetic force) generated in the magnetization process during the manufacture of the rotor 12, and in Fig. 4(b), F2 denotes the force (centrifugal force) generated by the rotation of the rotor 12 during use of the rotating electric machine 10.

[0053] As shown in Fig. 4(a), in the magnetization step during manufacturing of the rotor 12, a magnetizing magnetic field is applied in a direction perpendicular to the longitudinal direction of the permanent magnet 22 by a magnetizing coil C arranged on the outer periphery of the rotor core 21. For example, in magnetizing the S magnetic pole, as shown in Fig. 4(a), a magnetizing magnetic field is applied from the radially outer side toward the radially inner side, and a force F1 acts on the permanent magnet 22 in a direction pressing it against the inner core surface 25b of the magnet accommodating hole 24. In this case, the force F1 acts on the radially outer side of the permanent magnet 22 (the outer core outer periphery side) in a direction that peels off the outer resin 28A, but peeling or damage to the outer resin 28A is suppressed because the adhesive strength of the outer resin 28A is high.

[0054] On the other hand, as shown in FIG. 4( b), when the rotating electric machine 10 is in use, a force F2 acts on the permanent magnet 22 due to the rotation of the rotor 12. In this case, because the adhesive strength of the outer resin 28A of the resins 28A, 28B on the outer and inner sides of the magnet accommodating hole 24 is enhanced, the permanent magnet 22 remains fixed on the outer core surface 25a side even when centrifugal force of the rotor 12 is generated. Furthermore, while there is concern about peeling or damage to the resin due to thermal stress or vibrations when the rotating electric machine 10 is in use, the enhanced adhesive strength of the outer resin 28A also suppresses peeling or damage to the outer resin 28A. As a result, the permanent magnet 22 remains fixed within the magnet accommodating hole 24.

[0055] Next, a description will be given of a method for manufacturing the rotor 12. Fig. 5 is a process chart showing the manufacturing procedure of the rotor 12.

[0056] First, in the core manufacturing process, a plurality of electromagnetic steel sheets are stacked and fixed together to manufacture the rotor core 21.

[0057] In the assembly process, the unmagnetized permanent magnets 22 are accommodated in the magnet accommodating holes 24 of the rotor core 21 together with uncured resin 28. As a result, the resin 28 is applied to the outer core surface 25a and the inner core surface 25b in the magnet accommodating holes 24, and the unmagnetized permanent magnets 22 are assembled in the magnet accommodating holes 24. More specifically, as this assembly process, it is preferable to assemble the permanent magnets 22 in the magnet accommodating holes 24 with the resin 28 applied to the outer core surface 25a and the inner core surface 25b in the magnet accommodating holes 24. Alternatively, the permanent magnets 22 may be assembled in the magnet accommodating holes 24, and then the resin 28 may be applied in the magnet accommodating holes 24 after the assembly. It is also possible to apply resin 28 to one of the outer core surface 25a and the inner core surface 25b before accommodating the permanent magnet 22 in the magnet accommodating hole 24, and then apply resin 28 to the other of the outer core surface 25a and the inner core surface 25b after accommodating the permanent magnet 22.

[0058] As described above, it is preferable to use different resin materials on the outer core surface 25a side and the inner core surface 25b side.

[0059] In the curing process, the resins 28A and 28B in the magnet accommodating hole 24 are cured so that the adhesive strength of the outer resin 28A is stronger than that of the inner resin 28B. In this case, if a thermosetting resin is used, the resins 28A and 28B are cured by applying thermal energy to the resins 28A and 28B. The resins 28A and 28B have different degrees of cure after curing, and it is preferable that the outer resin 28A has a higher degree of cure than the inner resin 28B. In this case, by curing the outer resin 28A faster than the inner resin 28B, the degrees of cure of the resins 28A and 28B can be made different.

[0060] The adhesive strength of each resin 28A, 28B may be made different by varying the amount of thermal energy applied when curing the resin between the outer core surface 25a and the inner core surface 25b. In this case, thermal energy may be applied from the outer periphery of the rotor core 21. That is, by applying thermal energy from the outer periphery of the rotor core 21, the amount of energy input is greater on the outer core surface 25a side than on the inner core surface 25b side. As a result, the degree of cure of the outer resin 28A is higher than the degree of cure of the inner resin 28B.

[0061] Then, in the magnetization process, after each of the resins 28A and 28B has hardened, a magnetizing magnetic field is applied radially to the permanent magnets 22 to magnetize them. Specifically, a magnetizing device disposed radially outside the rotor core 21 is used to magnetize the permanent magnets 22 by an external magnetic field generated by the magnetizing device. As a result, the permanent magnets 22 in the magnet accommodating holes 24 are magnetized for each magnetic pole. In this magnetization process, a radial force acts on the permanent magnets 22 due to the magnetizing magnetic field applied radially. However, because the adhesive strength of the outer resin 28A is strong and the adhesive strength of the inner resin 28B is weak, peeling and damage to the resin may occur on the inner circumferential side, but peeling and damage to the resin on the outer circumferential side is suppressed.

[0062] According to the present embodiment described above in detail, the following excellent effects can be obtained.

[0063] Within magnet accommodating holes 24 of rotor core 21, the adhesive strength of outer resin 28A on the outer core surface 25a side is set to be stronger than the adhesive strength of inner resin 28B on the inner core surface 25b side. In this case, due to the difference in adhesive strength of the resin between outer core surface 25a and inner core surface 25b, even if peeling or the like of resin 28 occurs due to thermal stress, vibration, or the like, the peeling or the like occurs preferentially on the inner core surface 25b side, and the fixed state (adhered state) of permanent magnet 22 by resin 28 is maintained on the outer core surface 25a side.

[0064] Furthermore, when the rotating electric machine 10 is in use, centrifugal force of the rotor 12 acts on the permanent magnets 22, but because the adhesive strength of the resin 28 is increased on the outer core surface 25a side of the outer core surface 25a and the inner core surface 25b, the fixed state of the permanent magnets 22 is maintained on the outer core surface 25a side even in a situation where centrifugal force is generated on the rotor 12. As a result, the permanent magnets 22 can be suitably held in the magnet accommodating holes 24 in a desired fixed state.

[0065] Furthermore, as described above, the configuration in which the adhesive strength of the inner resin 28B inside the magnet accommodating hole 24 is intentionally weakened makes it possible to minimize the amount of resin used, especially the amount of resin with a high degree of hardening. This allows for cost reductions due to the reduction in resin, as well as reductions in energy required for resin hardening and CO2 emissions.

[0066] The resin materials used on the outer core surface 25a side and the inner core surface 25b side are different in at least one of material composition and compounding ratio. Also, the degree of cure of the resin 28 on the outer core surface 25a side and the inner core surface 25b side is different. These configurations make it possible to preferably realize a configuration in which the adhesive strength of the resin 28 on the outer core surface 25a side and the inner core surface 25b side is different.

[0067] In the curing process during the manufacture of rotor 12, the adhesive strength of outer resin 28A is made stronger than the adhesive strength of inner resin 28B by making the amount of thermal energy different between outer core surface 25a and inner core surface 25b. This makes it possible to preferably realize a configuration in which the adhesive strengths of resins 28A and 28B are different between the outer and inner sides.

[0068] In the curing process, the resins 28A, 28B are cured by applying thermal energy from the outer periphery side of the rotor core 21. In this case, it is possible to preferably realize a configuration in which the adhesive strength of the resins 28A, 28B differs between the outer periphery side core surface 25a and the inner periphery side core surface 25b, while taking into consideration the difference in the degree of curing of the resins 28A, 28B due to the difference in the amount of energy input.

[0069] In the configuration in which the magnet accommodating hole 24 is provided as a pair of holes forming a substantially V-shape as described above, the following configuration can be used, which will be explained with reference to FIG.

[0070] 6, as described above, outer resin 28A is disposed on the outer periphery of permanent magnet 22 within magnet accommodating hole 24, and inner resin 28B is disposed on the inner periphery of permanent magnet 22. Also, within magnet accommodating hole 24, on the inner core surface 25b side, the adhesive strength of resin 28 differs between the magnetic pole center side (d-axis side) and the opposite side (q-axis side), so that the adhesive strength of the resin is higher on the opposite side of the magnetic pole center, i.e., part A in FIG. 6. Note that in FIG. 6, outer resin 28A with high adhesive strength is preferably filled in part A so as to wrap around from the outer core surface 25a side to the inner core surface 25b side.

[0071] According to the above configuration, even if centrifugal force acts on permanent magnet 22 toward both ends of the V shape when rotor 12 rotates, resin 28 remains without breaking at the locations where centrifugal force acts on permanent magnet 22, i.e., the locations where resin 28 receives force in the compressive direction. Therefore, it is possible to maintain the fixation of permanent magnet 22 in an appropriate manner.

[0072] Also, in Figure 6, if the interface between the inner core surface 25b and the inner resin 28B is the first interface S1 and the interface between the permanent magnet 22 and the inner resin 28B is the second interface S2, the adhesive strength to the inner resin 28B at each of these interfaces S1 and S2 may be different from each other.

[0073] As described above, in a configuration in which the adhesive strength of the inner resin 28B is weak on the inner core surface 25b side within the magnet accommodating hole 24, peeling of the inner resin 28B is likely to occur. However, if peeling occurs arbitrarily between the first interface S1 on the inner core surface 25b side and the second interface S2 on the permanent magnet 22 side, peeled pieces of resin may be generated within the magnet accommodating hole 24 and may enter the air gap between the rotor 12 and the stator 13 in the rotating electric machine 10. In this regard, because the adhesive strength of the inner resin 28B is different between the first interface S1 and the second interface S2, when peeling of the inner resin 28B occurs, peeling occurs preferentially at one of the interfaces S1 and S2. This makes it possible to suppress the generation of peeled pieces of resin due to peeling of the inner resin 28B.

[0074] (Second embodiment) Next, the configuration of the second embodiment will be described, focusing on the differences from the first embodiment. In this embodiment, the configuration of the magnet accommodating holes 24 of the rotor core 21 and the permanent magnets 22 in the rotor 12 differs from that of the above embodiment. Figure 7 is a partial cross-sectional view of the rotor 12 in this embodiment.

[0075] As shown in Fig. 7, the rotor core 21 is provided with magnet accommodating holes 24 that extend linearly in the circumferential direction for each magnetic pole. The magnet accommodating holes 24 are provided in a direction perpendicular to the d-axis, which is the center of the magnetic pole. Permanent magnets 22 are accommodated in the magnet accommodating holes 24 and adhesively fixed therein by resins 28A and 28B. In the magnet accommodating holes 24, there is an air gap on the q-axis side of both ends of the permanent magnets 22.

[0076] In the magnet accommodating hole 24, an outer resin 28A is interposed between the outer peripheral magnet surface 22a of the permanent magnet 22 and the outer peripheral core surface 25a, and an inner resin 28B is interposed between the inner peripheral magnet surface 22b of the permanent magnet 22 and the inner peripheral core surface 25b. As in the first embodiment, these resins 28A, 28B have different adhesive strengths, with the outer resin 28A having a stronger adhesive strength than the inner resin 28B. The specific configuration of each resin 28A, 28B is the same as in the first embodiment.

[0077] As described above, the adhesive strength of the resins 28A, 28B is different between the outer core surface 25a side and the inner core surface 25b side, so that even if peeling or the like of the resin occurs due to expansion and contraction of the resin, the peeling or the like occurs preferentially on the inner core surface 25b side. Therefore, the fixed state (adhered state) of the permanent magnet 22 by the resin is maintained on the outer core surface 25a side.

[0078] Next, a description will be given of the configuration of the longitudinal cross section of the rotor 12 in this embodiment. Fig. 8 is a longitudinal cross section of the rotor 12. In Fig. 8, the left-right direction is the axial direction.

[0079] The rotor core 21 is divided into multiple pieces in the axial direction, and is configured by, for example, four core pieces 41 stacked in the axial direction. Each core piece 41 is formed as a laminate of multiple electromagnetic steel sheets. Each core piece 41 is fixed to the rotating shaft 11 with its position restricted by end plates 42 provided on both axial sides.

[0080] A magnet accommodating hole 24 is formed in each core piece 41, and when the core pieces 41 are stacked, the magnet accommodating holes 24 of each core piece 41 are continuous in the axial direction. The magnet accommodating holes 24 of each core piece 41 may be aligned with one another in the circumferential direction, or may be partially offset in the circumferential direction.

[0081] A permanent magnet 22 is accommodated in the magnet accommodating hole 24 of each core piece 41 while being adhered with resin 28. In this case, in particular, the permanent magnets 22 provided for each core piece 41 are spaced apart from one another in the axial direction, with resin 28 interposed between the respective permanent magnets 22.

[0082] In the present embodiment, as in the first embodiment, the adhesive strength of the outer resin 28A within the magnet accommodating hole 24 is made stronger than the adhesive strength of the inner resin 28B, thereby enabling the permanent magnet 22 to be suitably held in the desired fixed state.

[0083] In the configuration of the first embodiment, similarly to this embodiment, the rotor core 21 and the permanent magnet 22 can each be configured to be divided into a plurality of pieces in the axial direction.

[0084] (Other embodiments) The above embodiment may be modified as follows, for example.

[0085] The following configurations can be used to make the adhesive strength of the resins 28A, 28B different between the outer circumferential side and the inner circumferential side within the magnet accommodating hole 24.

[0086] Each of the resins 28A and 28B is configured to contain air bubbles, with more air bubbles present in the inner resin 28B than in the outer resin 28A. In this case, the difference in adhesive strength is achieved by utilizing the reduction in strength caused by the air bubbles.

[0087] It is preferable to make the surface roughness different between the outer circumferential side and the inner circumferential side of the permanent magnet 22. In this case, the difference in adhesive strength is realized by making the surface roughness of the outer circumferential side of the permanent magnet 22 rougher than the surface roughness of the inner circumferential side.

[0088] The thickness of resins 28A, 28B may be different between the outer core surface 25a side and the inner core surface 25b side. In this case, the difference in adhesive strength is achieved by making the thickness of outer resin 28A thinner than the thickness of inner resin 28B.

[0089] Of the outer and inner circumferential sides of the permanent magnet 22, the outer circumferential side may be subjected to a surface treatment to improve the adhesiveness of the resin 28. In this case, the difference in adhesive strength is achieved by the surface treatment of the permanent magnet 22.

[0090] The areas to which the resins 28A, 28B are applied may be different between the outer core surface 25a side and the inner core surface 25b side within the magnet accommodating hole 24, with the area to which the resins 28A, 28B are applied being larger on the outer core surface 25a side than on the inner core surface 25b side. This makes it possible to preferably realize a configuration in which the adhesive strength of the resins 28A, 28B is different between the outer core surface 25a side and the inner core surface 25b side.

[0091] During the manufacture of the rotor 12, the resins 28A, 28B may be cured by thermal energy generated by energizing the stator windings 33. In this case, before the curing step, the stator 13 is assembled to the radially outer side of the rotor core 21. Then, in the curing step, the resins 28A, 28B are cured from the radially outer side by thermal energy generated by energizing the stator windings 33. According to the above manufacturing method, the resin 28 can be cured appropriately in a series of manufacturing steps for the rotating electric machine 10, without using a heating device dedicated to curing.

[0092] In the above embodiment, the permanent magnet 22 before magnetization is assembled into the magnet accommodating hole 24 in the assembly process. However, this may be modified so that the permanent magnet 22 after magnetization is assembled into the magnet accommodating hole 24.

[0093] Photocurable resin can be used instead of thermosetting resin as resin 28 filled in magnet accommodating holes 24. In this case, by applying different amounts of light energy to the outer core surface 25a side and the inner core surface 25b side in the curing process, the adhesive strength of outer resin 28A is made stronger than the adhesive strength of inner resin 28B. In this case, it is preferable to apply light energy from the outer periphery side of rotor core 21 to cure resin 28.

[0094] The following describes modified examples of the magnet accommodating holes 24 and permanent magnets 22 in the rotor 12. In each of the configurations described below, the adhesive strength of the outer resin 28A within the magnet accommodating holes 24 is stronger than the adhesive strength of the inner resin 28B, as in the above configurations.

[0095] In the configuration shown in Fig. 9(a), a pair of magnet accommodating holes 24 are provided as a pair of holes forming a substantially V-shape. In comparison with Fig. 3(b), this configuration is such that the second accommodating portion 26 is omitted from the magnet accommodating holes 24.

[0096] In the configuration shown in Figure 9(b), the magnet accommodating holes 24 for each magnetic pole are provided with a magnet accommodating hole 24A arranged in a direction perpendicular to the d-axis, and a pair of magnet accommodating holes 24B on both circumferential sides of the magnet accommodating hole 24A, which extend in a direction inclined relative to an orthogonal line perpendicular to the d-axis.

[0097] The rotor core 21 may have magnet accommodating holes 24 arranged in multiple layers in the radial direction. Note that, for each magnetic pole, the number of magnet accommodating holes 24 may be the same in each layer aligned radially inside and outside, or may be greater on the radially outer side than on the radially inner side. The same applies to the permanent magnets 22.

[0098] In FIG. 10(a), the magnet accommodating hole 24 for each magnetic pole is configured by a pair of holes each having a substantially V-shape, which are provided in two layers in the radial direction.

[0099] In Figure 10(b), the magnet accommodating hole 24 for each magnetic pole is configured by a pair of approximately V-shaped hole portions and a hole portion extending in a direction perpendicular to the d-axis, arranged in two radial layers.

[0100] In Figure 10(c), the configuration includes a radially outer magnet accommodating hole 24 consisting of a pair of approximately V-shaped hole portions, and four magnet accommodating holes 24 arranged to surround the radially outer magnet accommodating hole 24.

[0101] The rotating electric machine 10 may have an outer rotor structure. The rotating electric machine 10 may be used for purposes other than a vehicle traction motor, and may be used in a wide range of moving objects or in industrial or household electrical equipment. [Explanation of symbols]

[0102] 10... rotating electric machine, 12... rotor, 21... rotor core, 22... permanent magnet, 24... magnet accommodating hole, 25a... outer circumferential core surface, 25b... inner circumferential core surface, 28... resin.

Claims

1. A rotor (12) for a rotating electric machine (10) includes a rotor core (21) and permanent magnets (22) accommodated in a plurality of magnet accommodating holes (24) provided in the rotor core, and is disposed radially opposite a stator (13), The rotor core has a pair of magnet accommodating holes arranged on both sides of the magnetic pole center for each magnetic pole, and each having a substantially V-shaped hole portion such that the opposing distance between the stator and the magnet accommodating holes decreases from the magnetic pole center side toward the magnetic pole boundary side, and the permanent magnets are fixed in the magnet accommodating holes using resin (28), The permanent magnet is accommodated in the magnet accommodating hole with the resin interposed between it and an outer core surface (25a) which is an outer core wall surface, and between it and an inner core surface (25b) which is an inner core wall surface, A rotor for a rotating electric machine, wherein the adhesive strength of the resin on the outer core surface side is higher than the adhesive strength of the resin on the inner core surface side, and the adhesive strength of the resin on the inner core surface side is different between the magnetic pole center side and the opposite side, and the adhesive strength of the resin is higher on the opposite side of the magnetic pole center.

2. 2. The rotor of a rotating electric machine according to claim 1, wherein the resin on the outer core surface side and the resin on the inner core surface side are made of resin materials that differ in at least one of material composition and compounding ratio.

3. 3. The rotor of a rotating electric machine according to claim 1, wherein the resin on the outer core surface side and the resin on the inner core surface side have different degrees of hardening, and the resin on the outer core surface side has a higher degree of hardening than the resin on the inner core surface side.

4. A rotor for a rotating electric machine according to any one of claims 1 to 3, wherein the area of ​​the resin applied is different between the outer core surface side and the inner core surface side, and the area applied on the outer core surface side is larger than that on the inner core surface side.

5. an inner resin (28B) is interposed as the resin between the inner core surface and the permanent magnet in the magnet accommodating hole, A rotor for a rotating electric machine according to any one of claims 1 to 4, wherein when the interface between the inner core surface and the inner resin is defined as a first interface (S1) and the interface between the permanent magnet and the inner resin is defined as a second interface (S2), the adhesive strengths of the first interface and the second interface to the inner resin are different from each other.

6. A method for manufacturing a rotor (12) of a rotating electric machine (10), the rotor (12) including a rotor core (21) and permanent magnets (22) accommodated in a plurality of magnet accommodating holes (24) provided in the rotor core, the rotor being disposed radially opposite a stator (13), the method comprising: The rotor core has a pair of magnet accommodating holes, each of which has a pair of holes arranged on either side of a magnetic pole center for each magnetic pole, and which are substantially V-shaped so that the opposing distance between the magnet accommodating holes and the stator decreases from the magnetic pole center toward the magnetic pole boundary, an assembling process in which resin (28) is applied to an outer core surface (25a) which is an outer core wall surface and an inner core surface (25b) which is an inner core wall surface in the magnet accommodating hole, and the permanent magnet before magnetization is assembled in the magnet accommodating hole; a curing process in which the resin in the magnet accommodating hole is cured to make the adhesive strength of the resin on the outer core surface side stronger than the adhesive strength of the resin on the inner core surface side, and the adhesive strength of the resin on the inner core surface side differs between the magnetic pole center side and the opposite side, so that the adhesive strength of the resin is stronger on the opposite side of the magnetic pole center; a magnetizing step of applying a magnetizing magnetic field to the permanent magnet in a radial direction after the resin has hardened, thereby magnetizing the permanent magnet; A method for manufacturing a rotor having the above structure.

7. the resin is made of a resin material that is hardened by thermal energy or light energy, 7. A rotor manufacturing method as described in claim 6, wherein in the curing process, the adhesive strength of the resin on the outer core surface side is made higher than the adhesive strength of the resin on the inner core surface side by making the amount of heat energy or light energy different between the outer core surface side and the inner core surface side.

8. 8. The method for manufacturing a rotor according to claim 7, wherein in the curing process, the resin on the outer core surface side and the resin on the inner core surface side are cured by applying thermal energy or light energy from the outer side of the rotor core.

9. Before the hardening step, a stator (13) having a stator winding (33) is disposed at a position radially opposite to the rotor core; 9. The method for manufacturing a rotor according to claim 8, wherein in the curing step, the resin on the outer core surface side and the resin on the inner core surface side are cured by thermal energy generated by passing current through the stator winding.

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