Manufacturing method for rotor for rotating electric machine

Abstract

To insert a permanent magnet to a desired position in a magnet hole and fix the permanent magnet by resin material.SOLUTION: A manufacturing method for a rotor for a rotary electric machine is disclosed, including a step of preparing a rotor core with axial magnet holes and permanent magnets that can be inserted into the magnet holes, a resin injection step of injecting resin material with different melting and hardening temperatures in a molten state into the magnet holes, a magnet insertion step of inserting a permanent magnet into the magnet holes after the resin injection step in such a way that the molten resin material reaches around the permanent magnet, and a resin hardening step of hardening the resin material after the magnet insertion step.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a rotor for a rotating electric machine. [Background technology]

[0002] Regarding a method for manufacturing a rotor for a rotating electric machine, a technique is known in which a solid resin material is inserted into a magnet hole, and then a preheated permanent magnet is inserted into the magnet hole to melt at least a portion of the resin material, and then the core is heated to harden the resin material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-7565 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the above-described conventional technology, it is difficult to maintain the entire resin material in the magnet hole in a molten state when inserting the permanent magnet, making it difficult to insert the permanent magnet into the desired position in the magnet hole.

[0005] Therefore, in one aspect, an object of the present disclosure is to insert a permanent magnet into a magnet hole at a desired position and fix it with a resin material. [Means for solving the problem]

[0006] In one aspect, a method for manufacturing a rotor includes providing a rotor core having axial magnet holes and permanent magnets insertable into the magnet holes; a resin injection step of injecting a resin material having a melting temperature and a hardening temperature different from each other in a molten state into the magnet hole; a magnet insertion step of inserting the permanent magnet into the magnet hole in such a manner that the molten resin material reaches around the permanent magnet after the resin injection step; and a resin curing step of curing the resin material extending around the permanent magnets inserted in the magnet inserting step. [Effects of the Invention]

[0007] In one aspect, the present disclosure allows a permanent magnet to be inserted into a desired position within a magnet hole and fixed with a resin material. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view schematically showing a cross-sectional structure of a motor according to an embodiment. [Figure 2] 1 is a cross-sectional view of a rotor (a cross-sectional view taken along a plane perpendicular to the axial direction). [Figure 3] FIG. 3 is an enlarged view of a portion relating to one magnetic pole shown in FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view taken along line AA in FIG. 3. [Figure 5] 4 is a flowchart showing an outline of a method for manufacturing a motor according to the present embodiment. [Figure 6] FIG. [Figure 7] FIG. 10 is an explanatory diagram of a nozzle positioning step. [Figure 8] FIG. [Figure 9] FIG. 10 is an explanatory diagram of a magnet insertion process. [Figure 10] FIG. 10 is an explanatory diagram of a preferred example of a magnet insertion step, and is a cross-sectional view schematically showing the state before the start of the step. [Figure 11] FIG. 10 is a schematic cross-sectional view illustrating a resin curing step. DETAILED DESCRIPTION OF THE INVENTION

[0009] Each embodiment will be described in detail below with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples and are not intended to limit the scope of the invention. In addition, shapes and the like in the drawings may be partially exaggerated for the sake of explanation.

[0010] Fig. 1 is a cross-sectional view that schematically shows the cross-sectional structure of a motor 1 according to one embodiment. Fig. 2 is a cross-sectional view (a cross-sectional view taken along a plane perpendicular to the axial direction) of a rotor 30. Note that in Fig. 2 and other figures, for ease of viewing, reference symbols may be assigned only to some of the parts that exist with the same attribute.

[0011] 1 shows a rotating shaft 12 of a motor 1. In the following description, the axial direction refers to the direction in which the rotating shaft (center of rotation) 12 of the motor 1 extends, the axially outer side refers to the side away from the axial center of the rotor core 32, and the axially inner side refers to the side toward the axial center of the rotor core 32. The radial direction refers to the radial direction centered on the rotating shaft 12, the radially outer side refers to the side away from the rotating shaft 12, and the radially inner side refers to the side toward the rotating shaft 12. The circumferential direction corresponds to the direction of rotation around the rotating shaft 12.

[0012] The motor 1 may be a motor for driving a vehicle, such as that used in a hybrid vehicle or an electric vehicle, but the motor 1 may also be used for any other purpose.

[0013] The motor 1 is an inner rotor type, and the stator 21 is provided so as to surround the radial outside of the rotor 30. The radial outside of the stator 21 is fixed to the motor housing 10. The stator 21 includes a stator core 211 made of, for example, annular laminated steel plates of a magnetic material, and a plurality of slots (not shown) are formed radially inside the stator core 211, around which the coils 22 are wound.

[0014] The rotor 30 is disposed radially inside the stator 21 .

[0015] The rotor 30 includes a rotor core 32, a rotor shaft 34, end plates 35A and 35B, and a permanent magnet 62.

[0016] The rotor core 32 is fixed to the radially outer surface of the rotor shaft 34 and rotates integrally with the rotor shaft 34. The rotor core 32 has an axial hole 320 (see FIG. 2 ), into which the rotor shaft 34 is fitted. The rotor core 32 may be fixed to the rotor shaft 34 by shrink fitting, press fitting, or the like. For example, the rotor core 32 may be connected to the rotor shaft 34 by a key connection or a spline connection. The rotor shaft 34 is rotatably supported in the motor housing 10 via bearings 14 a and 14 b. The rotor shaft 34 defines the rotary axis 12 of the motor 1.

[0017] The rotor core 32 is formed, for example, from annular laminated steel plates of a magnetic material. Permanent magnets 62 (see FIG. 2) are embedded inside the rotor core 32. That is, the rotor core 32 has magnet holes 322 (see FIG. 2) that penetrate in the axial direction, and the permanent magnets 62 are inserted into and fixed in the magnet holes 322. In a modified example, the rotor core 32 may be formed from a green compact obtained by compressing and solidifying magnetic powder.

[0018] 2, rotor core 32 has a rotationally symmetric shape about rotation axis 12 when viewed in the axial direction. In the example shown in FIG. 2, rotor core 32 has a shape in which each set of permanent magnets 62 overlaps every 45 degrees of rotation about rotation axis 12.

[0019] The multiple permanent magnets 62 may be made of neodymium or the like. In this embodiment, as an example, as shown in FIG. 2 , the multiple permanent magnets 62 are arranged in pairs when viewed in the axial direction. In this case, a common magnetic pole is formed between the pairs of permanent magnets 62. The multiple permanent magnets 62 are arranged in a manner such that south and north poles alternate in the circumferential direction. Although the number of magnetic poles is eight in this embodiment, the number of magnetic poles is arbitrary. In this embodiment, the permanent magnets 62 have the same linear shape when viewed in the axial direction, but they may have different shapes. Furthermore, at least one of the permanent magnets 62 may have an arc shape when viewed in the axial direction. Furthermore, another pair of permanent magnets may be arranged at a different radial position from the pair of permanent magnets 62. In this case, the fixing structure and the like related to the permanent magnets 62 described below can be similarly applied to the other permanent magnets.

[0020] 1 shows the motor 1 having a specific structure, but the structure of the motor 1 is not limited to such a specific structure. For example, in FIG. 1, the rotor shaft 34 is hollow, but it may be solid.

[0021] Next, with reference to Figure 3 onwards, a detailed description will be given of the fixing structure of the permanent magnets 62 in the rotor core 32. Although the following describes the configuration relating to one magnetic pole, the same may be true for the configurations relating to the other magnetic poles.

[0022] FIG. 3 is a plan view schematically showing the fixing structure of the permanent magnets 62 in the rotor core 32 according to this embodiment, and is an enlarged view of a portion relating to one magnetic pole shown in FIG. 2. The configuration relating to one magnetic pole is basically symmetrical with respect to the d-axis (written as "d-axis" in English in FIGS. 2 and 3). The d-axis corresponds to the direction of the magnetic field generated by the permanent magnets 62 arranged in the rotor 30. FIG. 4 is a schematic cross-sectional view taken along line AA in FIG. 3.

[0023] In Figure 4, the Z direction is defined along with the Z1 side and Z2 side, which are both sides of the Z direction. The Z direction is parallel to the axial direction of the motor 1. In the following explanation, the Z direction corresponds to the up-down direction, but this may differ from the up-down direction when the motor 1 is mounted on a vehicle. The Z1 side and Z2 side represent a relative positional relationship, with the Z1 side corresponding to the upper side.

[0024] In this embodiment, as shown in FIGS. 3 and 4, the permanent magnets 62 are fixed in the magnet holes 322 of the rotor core 32 by the resin material layers 72.

[0025] The resin material layer 72 may be formed of, for example, a thermosetting resin or a thermoplastic resin. A method for forming the resin material layer 72 will be described in detail later. The resin material layer 72 is bonded to both the permanent magnet 62 and the rotor core 32 with, for example, an anchor effect. In this case, the anchor effect on the permanent magnet 62 side may be achieved by roughening an insulating layer (not shown) provided as a surface coating of the permanent magnet 62. The anchor effect on the rotor core 32 side may be achieved by forming the rotor core 32 from laminated steel plates.

[0026] 4, the resin material layer 72 may be bonded to the permanent magnet 62 in such a manner that both axial end faces 621, 622 of the permanent magnet 62 are exposed. In other words, the resin material layer 72 may be bonded only to the side faces of the surface of the permanent magnet 62 that are in a direction intersecting the axial direction. However, of both axial end faces 621, 622 of the permanent magnet 62, the material for the resin material layer 72 may be attached to the end face 622.

[0027] In this embodiment, the resin material layer 72 may extend between the permanent magnet 62 and the peripheral wall surface of the magnet hole 322 in a manner that fills the space between the permanent magnet 62 and the peripheral wall surface of the magnet hole 322 without any gaps. In this case, the resin material layer 72 is bonded to the permanent magnet 62 in a manner that surrounds the permanent magnet 62 over the entire circumference when viewed in the axial direction. In other words, the resin material layer 72 is bonded to all four faces of the permanent magnet 62. Furthermore, the resin material layer 72 is bonded to the peripheral wall surface of the magnet hole 322 over the entire circumference of the permanent magnet 62 when viewed in the axial direction. In other words, the resin material layer 72 is bonded to the magnet hole 322 over the entire circumference of the peripheral wall surface of the magnet hole 322. This allows the permanent magnet 62 to be fixed more firmly to the rotor core 32 than when the resin material layer is bonded only to a portion of the entire circumference of the permanent magnet 62.

[0028] Next, a method for manufacturing the motor 1 according to this embodiment will be described with reference to FIG. 5 and subsequent figures.

[0029] In the following description, as described above, the axial direction refers to the direction in which the central axis I0 of the rotor core 32 (workpiece W) corresponding to the rotating shaft 12 of the motor 1 extends, and the radial direction refers to the radial direction centered on the central axis I0 of the rotor core 32. Therefore, the radially outer side refers to the side away from the central axis I0 of the rotor core 32, and the radially inner side refers to the side toward the central axis I0 of the rotor core 32. Furthermore, the circumferential direction corresponds to the direction of rotation around the central axis I0 of the rotor core 32.

[0030] FIG. 5 is a flowchart that outlines the flow of a manufacturing method for motor 1 according to this embodiment. FIGS. 6 to 10 are explanatory diagrams of specific steps in the manufacturing method shown in FIG. 5. FIG. 6 is an explanatory diagram of a workpiece supporting step, FIG. 7 is an explanatory diagram of a nozzle positioning step, FIG. 8 is an explanatory diagram of a resin injection step, and FIG. 9 is an explanatory diagram of a magnet insertion step, each of which is a cross-sectional view that schematically shows the state after the steps. Note that FIG. 8 is a schematic view of the state after the resin injection step for one magnet hole 322. FIG. 10 is an explanatory diagram of a preferred example of the magnet insertion step, and is a cross-sectional view that schematically shows the state before the step starts. FIG. 11 is a schematic cross-sectional view that explains the resin hardening step.

[0031] This manufacturing method first includes a steel plate lamination process (step S1) in which a plurality of steel plates 3250 are laminated as a preparation process for preparing permanent magnets 62 and a workpiece W of rotor core 32. In the case of rotor core 32 formed by rotating and stacking a plurality of laminated blocks, workpiece W of rotor core 32 may be a unit of laminated block.

[0032] Next, as shown schematically in FIG. 10, this manufacturing method includes a workpiece supporting step (step S2) of placing the workpiece W on a support jig 120. The support jig 120 is one element of the manufacturing apparatus 100, and may support the workpiece W while transporting the workpiece W between each process. In this case, the support jig 120 may be in the form of a movable conveyor or the like, or may be in the form of a transport tray that is transported by being placed on a conveyor or the like. The support jig 120 may also be configured to be grasped by a transport robot.

[0033] Next, this manufacturing method includes a preheating step (step S3) of preheating the workpiece W. The preheating step may be achieved by an induction heating device, a heating furnace, or the like. In the case of an induction heating device, the induction heating device may be disposed radially inside and / or outside the rotor core 32 of the workpiece W. The preheating step (step S3) may be achieved by using a heating device 160 (see FIGS. 10 and 11) described below.

[0034] 7, the manufacturing method includes a nozzle positioning step (step S4) of positioning the nozzle 131 of the resin placement device 130 within the magnet hole 322 of the workpiece W on the support jig 120. The nozzle 131 of the resin placement device 130 may be positioned so that it can be inserted into and removed from the magnet hole 322 by moving up and down.

[0035] Next, as shown schematically in FIG. 8 , this manufacturing method includes a resin injection process (step S5) in which resin material 90 for forming the above-described resin material layer 72 is placed in a molten state within magnet hole 322. Note that resin material 90 may be molten in a resin injector (not shown) and introduced into nozzle 131. In the resin injection process, nozzle 131 may eject molten resin material 90 from outlet 1310 while outlet 1310 is inserted into magnet hole 322. In this case, compared to when resin material 90 is ejected (dripped) from outlet 1310 outside magnet hole 322, the amount of heat dissipation can be reduced (thus making it easier to maintain the molten state), and the occurrence of resin material 90 not entering magnet hole 322 due to scattering or the like can be prevented.

[0036] In this embodiment, the resin material 90 is a thermosetting resin material with a relatively low viscosity, and is injected in a pre-hardened state (a flowable molten state). Therefore, the resin material 90 injected into the magnet hole 322 flows (falls) downward due to its own weight and accumulates on the surface of the support jig 120 as its bottom.

[0037] In this embodiment, the resin material 90 preferably has a melt viscosity of 500 Pa·s or more, and more preferably 700 Pa·s or more, at 90°C and a shear rate of 1 / s. Such a resin material 90 may include a crystalline radical polymerizable composition such as that described in Japanese Patent Application Laid-Open No. 2021-161164, the disclosure of which is incorporated herein by reference.

[0038] In this embodiment, the resin material 90 has different melting and curing temperatures. For example, the resin material 90 described in Japanese Patent Application Laid-Open No. 2021-101605, the disclosure of which is incorporated herein by reference, may be used. In this case, the melting temperature (melting initiation temperature) is, for example, 60°C, and the curing temperature (curing initiation temperature) is, for example, 120°C. In this case, the resin temperature raised by the resin injector (not shown) during the resin injection process may be higher than the melting temperature (for example, 60°C) and lower than the curing temperature (for example, 80°C). This allows the resin material 90 to be placed (injected) into the magnet hole 322 in a pre-cured state (a flowable molten state) without starting to harden the resin material 90.

[0039] 9, the manufacturing method includes a magnet insertion step (step S6) of placing permanent magnets 62 in magnet holes 322 of the workpiece W on the support jig 120. The permanent magnets 62 may be inserted to a position where the lower end surface 622 abuts against the surface of the support jig 120 without any gap (i.e., a position where they make surface contact).

[0040] In this embodiment, the magnet insertion process (step S6) is performed while maintaining the resin material 90 in the magnet hole 322 of the workpiece W in a molten state. Therefore, when the permanent magnet 62 is inserted into the molten resin material 90 that has accumulated in the lower part of the magnet hole 322 of the workpiece W (the lower part with the surface of the support jig 120 as the lower surface), the molten resin material 90 is pushed aside and rises by an amount corresponding to the volume of the permanent magnet 62. At this time, the molten resin material 90 reaches the periphery of the permanent magnet 62 (it is pushed up by the permanent magnet 62 and reaches the periphery of the permanent magnet 62), and extends in the same extension range as the extension range of the resin material layer 72 described above with reference to FIG. 3.

[0041] In this embodiment, the resin material 90 has a relatively low melt viscosity as described above, and therefore can easily spread without gaps around the permanent magnet 62 during the magnet insertion process. That is, the resin material 90 in the magnet hole 322 can easily wrap around the permanent magnet 62 while being pushed aside by the permanent magnet 62. This increases the fixing strength of the resin material layer 72 formed from the resin material 90 (fixing strength related to the permanent magnet 62).

[0042] In this embodiment, the resin material 90 preferably has a characteristic that the curing reaction does not substantially proceed when in a molten state below the curing temperature. The term "the curing reaction does not substantially proceed" may include, for example, a state in which the content of the curing reaction material is 10% or less. In this case, even if the molten state is maintained for a relatively long time, the resin material 90 can maintain a relatively low melt viscosity as described above. Therefore, the resin material 90 can also maintain a relatively low melt viscosity as described above in the magnet insertion step (step S6) performed after the resin injection step (step S5). This allows the resin material 90 to easily and tightly extend around the permanent magnet 62 during the magnet insertion step (step S6).

[0043] In this embodiment, the amount V2 (ml) of resin material 90 injected into one magnet hole 322 is determined based on the volume V0 (cm 3 ) and the volume V1 (cm 3 ) of the permanent magnet 62 inserted into the one magnet hole 322. 3 ) by a margin α (ml). In other words, V2 = V0 - V1 - α. This reduces the possibility that the molten resin material 90 pushed aside by the permanent magnet 62 will overflow from the magnet hole 322 during the magnet insertion process (step S6).

[0044] The margin α is preferably set so that the resin material 90 does not reach the upper end surface 621 of the permanent magnet 62 during the magnet insertion process (step S6). This is because forming a layer of resin material 90 on the upper end surface 621 of the permanent magnet 62 causes a thermal stress problem. That is, due to the difference in linear expansion coefficients between the permanent magnet 62 and the resin material 90 layer, thermal stress occurs due to the difference in axial expansion and contraction that occurs between the two when the temperature changes. Therefore, by setting the margin α, it is possible to reduce the thermal stress problem caused by the difference in axial expansion and contraction between the resin material layer 72 and the permanent magnet 62.

[0045] In this embodiment, as described above, the magnet insertion step (step S6) is performed while maintaining the resin material 90 in the magnet holes 322 of the workpiece W in a molten state. In the magnet insertion step (step S6), heat may be applied to the resin material 90 in the magnet holes 322 of the workpiece W by the heating device 160 so that the molten state of the resin material 90 can be appropriately maintained. In this case, the temperature of the resin material 90 may be heated to a curing temperature or higher in a manner that does not impair the ease of insertion of the permanent magnets 62 during the magnet insertion step (step S6). In other words, the resin curing step (step S7), which will be described later, may be started in a manner that overlaps with the magnet insertion step (step S6). Alternatively, the temperature of the resin material 90 may be managed so that the temperature of the resin material 90 does not exceed the curing temperature (for example, so that the temperature is maintained at a temperature significantly lower than the curing temperature) until the magnet insertion step (step S6) is completed.

[0046] 10, the heating device 160, which is one element of the manufacturing apparatus 100, is disposed radially inside and outside the rotor core 32 of the workpiece W. In this case, the heating device 160 can heat the resin material 90 via the rotor core 32, thereby maintaining the resin material 90 in a molten state. The heating device 160 may be, for example, an induction heating device.

[0047] Such a heating device 160 may also function in the resin injection step (step S5). That is, in the resin injection step (step S5), heat may be applied by the heating device 160 to the resin material 90 poured into the magnet holes 322. In this case, too, the heating device 160 can heat the resin material 90 via the rotor core 32, so that the resin material 90 can be effectively maintained in a molten state.

[0048] Furthermore, instead of or in addition to heating by the heating device 160, a preheating step may be separately performed to preheat the permanent magnets 62 to be inserted. For example, a magnet preheating step (step S6A) to preheat the permanent magnets 62 may be separately performed before the magnet insertion step (step S6). In this case, heat can be directly applied to the resin material 90 by the permanent magnets 62 themselves. In this case, the magnet preheating step (step S6A) may preferably include heating the permanent magnets 62 to a temperature equal to or higher than the curing temperature of the resin material 90.

[0049] When the magnet preheating step (step S6A) is performed, the resin material 90 rises to above its curing start temperature due to the heat from the permanent magnet 62, starting from the portion of the resin material 90 that is in contact with the permanent magnet 62. In other words, the portion of the resin material 90 that is in contact with the permanent magnet 62 reaches above its curing start temperature and begins to thermally cure. In this case, the magnet insertion step is completed before the time it takes for the resin material 90 to cure (completely gel) (gel time or gelation time). Therefore, both ease of insertion of the permanent magnet 62 (ease of insertion so that the permanent magnet 62 can be positioned at the desired position within the magnet hole 322) and positional stability of the positioned permanent magnet 62 can be achieved. Note that positional stability of the permanent magnet 62 is achieved by making it more difficult for the permanent magnet 62 to move due to an increase in viscosity of the resin material 90 around the permanent magnet 62.

[0050] Note that even when the resin material 90 is a thermoplastic resin material, the molten state of the resin material 90 is maintained during the magnet insertion step (step S6) by heating the rotor core 32, etc. (or preheating in the preheating step described above). Furthermore, when the resin material 90 is a thermoplastic resin material, the temperature of the resin material 90 may be set relatively high during injection in the resin injection step (step S5). Even when the resin material 90 is a thermoplastic resin material, by appropriately setting the temperature of the resin material 90 during the magnet insertion step (step S6), it is possible to achieve both ease of insertion of the permanent magnets 62 (ease of positioning the permanent magnets 62 at the desired positions within the magnet holes 322) and positional stability of the positioned permanent magnets 62.

[0051] In this embodiment, since the resin material 90 has a relatively low melt viscosity as described above, the resin material 90 is more likely to leak from between the steel plates 3250 than when the resin material 90 has a relatively high melt viscosity. In this regard, in this embodiment, the resin material 90 is not pressurized within the magnet holes 322, thereby reducing the possibility of the resin material 90 leaking from between the steel plates 3250. That is, the magnet insertion process (step S6) is performed with the inside of the magnet holes 322 of the workpiece W open to atmospheric pressure. This significantly reduces the possibility of the resin material 90 leaking from between the steel plates 3250 in the magnet insertion process (step S6). Furthermore, if the rotor core 32 is heated by the heating device 160 to a temperature equal to or higher than the curing temperature of the resin material 90, curing of the resin material 90 begins when the resin material 90 comes into contact with the rotor core 32, thereby reducing the possibility of the resin material 90 leaking from between the steel plates 3250.

[0052] Alternatively, in this embodiment, in consideration of the relatively low melt viscosity of resin material 90, a pressed state in which rotor core 32 is pressed in the axial direction may be formed during the magnet insertion step (step S6). In other words, the magnet insertion step (step S6) may be performed together with the pressing step in which rotor core 32 is pressed in the axial direction.

[0053] 10, the manufacturing apparatus 100 has a pressing jig 170 that applies an axial force to the rotor core 32. In this case, the pressing jig 170 can press the workpiece W on the support jig 120 from above (see pressing force F80). This significantly reduces the possibility of the resin material 90 leaking out from between the steel plates 3250, even when the resin material 90 has a relatively low melt viscosity. The pressing jig 170 may have holes 172 that open the tops of the magnet holes 322. In this case, the permanent magnets 62 can be inserted while maintaining the pressing state of the pressing jig 170 against the rotor core 32.

[0054] Such a pressing jig 170 may also function in the resin injection step (step S5). That is, in the resin injection step (step S5), the resin material 90 may be placed in the magnet hole 322 under pressure from the pressing jig 170. In this case, it is possible to reduce the possibility that the resin material 90, which has a relatively low melt viscosity, will leak out from between the steel plates 3250 from the stage of the resin injection step (step S5). In this case, the resin injection step (step S5) may be realized by utilizing the hole 172 of the pressing jig 170.

[0055] Next, this manufacturing method includes a resin curing step (step S7) of curing the resin material 90 injected into the magnet hole 322. The resin curing step (step S7) includes raising the temperature of the molten resin material 90 to a temperature equal to or higher than the curing temperature. Note that if the resin material 90 is a thermoplastic resin material, the resin curing step (step S7) includes cooling the molten resin material 90 to a temperature equal to or lower than the curing temperature.

[0056] As described above, the resin curing step (step S7) may overlap with the magnet insertion step (step S6) in such a manner that the magnet insertion step (step S6) is completed before the completion of the resin curing step (step S7). That is, the resin curing step (step S7) may be performed in parallel with the magnet insertion step (step S6). From a similar perspective, the temperature of the resin material 90 may be raised to a temperature equal to or higher than the curing temperature in the resin injection step (step S5). That is, part of the resin curing step (step S7) may be achieved in the resin injection step (step S5).

[0057] Here, thermosetting resin, suitable for resin material 90, gels when heated above its curing temperature and then undergoes a state change known as complete curing. Gelling refers to a state in which the viscosity of the resin rapidly increases due to a crosslinking reaction, or in other words, transitions to a semi-solid state. Complete curing refers to a state in which the molecular chains become denser and more stable after the crosslinking reaction. Generally, the gelation time is greater than the complete curing time. When using a thermosetting resin, the completion of the resin curing step (step S7) corresponds to the completion of gelation of the entire resin material 90 injected into the magnet hole 322. Therefore, if the resin curing step (step S7) is performed in parallel with the magnet insertion step (step S6), the magnet insertion step (step S6) only needs to be completed by the time gelation is completed. In this case, the time required from the start of the magnet insertion step (step S6) to the completion of the resin curing step (step S7) can be shortened.

[0058] Furthermore, when the above-described preheating step (step S3) or magnet preheating step (step S6A) is performed, the resin curing step (step S7) may be achieved using only the heat from these steps. In other words, the resin curing step (step S7) does not require the application of new thermal energy (further heating). In particular, when the magnet preheating step (step S6A) is performed, as described above, the heat from the permanent magnets 62 initiates the curing reaction of the resin material 90. Therefore, even if the workpiece (the rotor core 32 into which the permanent magnets 62 are inserted) is moved for further heating, for example, displacement of the permanent magnets 62 due to the movement can be prevented.

[0059] 11, the heating device 160, which is one element of the manufacturing apparatus 100, is disposed radially inside and outside the rotor core 32 of the workpiece W, and is capable of heating and hardening the resin material 90 via the rotor core 32. The heating device 160 is, for example, an induction heating device, but may also be realized by a heating furnace.

[0060] The resin curing step (step S7) is preferably performed while applying an axial force F92 to the rotor core 32 of the workpiece W, as shown in FIG. 11 . In this case, the manufacturing apparatus 100 includes a pressing jig 170 that applies an axial force to the rotor core 32, as shown in FIG. 11 . The pressing jig 170 applies an axial force to the rotor core 32 by pressing the workpiece W on the support jig 120 from above (see pressing force F90). This applies an axial force to the rotor core 32 (see axial force F92). In this case, the magnitude of the axial force F92 is preferably set based on the magnitude of the axial force that the rotor core 32 receives when assembling the rotor 30 using the rotor core 32 in a later step S9. The axial force that the rotor core 32 receives when assembling the rotor 30 may correspond to, for example, the axial force (see force F10 in FIG. 1 ) that occurs when the rotor core 32 is clamped between the end plates 35A and 35B. In this case, the magnitude of the axial force F92 may correspond to a design value or a measured value of the magnitude of the axial force F10. The design value does not necessarily have to be a value written on a design drawing, but is a concept that includes a suitable value or a target value obtained in design through analysis or the like.

[0061] In this way, in this manufacturing method, the magnitude of the axial force F92 generated in the workpiece W may be set based on the magnitude of the axial force F10 (hereinafter also referred to simply as "axial force F10 in the mounted state") that the rotor core 32 receives when assembling the rotor 30.

[0062] Next, this manufacturing method includes a magnetizing step (step S8) in which permanent magnet 62 is magnetized. Note that, when performing a magnet preheating step (step S6A), etc., permanent magnet 62 will be heated before the magnetizing step (step S8), but this heating does not substantially cause any inconvenience (effect on the magnetization characteristics or the magnetic characteristics after magnetization). Note that the magnetizing step (step S8) may be performed at an earlier stage (for example, before the magnet insertion step or magnet preheating step).

[0063] Next, this manufacturing method includes a step (step S9) of assembling the rotor 30 with the rotor core 32 that has been subjected to step S7. For example, the rotor core 32 is fixed (e.g., press-fitted) to the rotor shaft 34, and end plates 35A and 35B are attached. This applies an axial force F10 (see FIG. 1) to the rotor core 32 in the assembled state. The rotor 30 assembled in this manner is then installed in a case (not shown) together with the stator 21 and other components, and the motor 1 is assembled.

[0064] According to this manufacturing method, as described above, the permanent magnet 62 is inserted into the magnet hole 322 with the molten resin material 90 extending into the magnet hole 322. Therefore, during the magnet insertion process (step S6), the molten resin material 90 in the magnet hole 322 does not provide significant resistance to the insertion of the permanent magnet 62. This allows the permanent magnet 62 to be positioned at a desired position within the magnet hole 322. This effect is more pronounced when the resin material 90 has a relatively low melt viscosity. In this way, according to this manufacturing method, the permanent magnet 62 can be inserted into a desired position within the magnet hole 322 and fixed therein by the resin material 90.

[0065] Furthermore, according to this manufacturing method, the magnet insertion step (step S6), or the resin injection step (step S5), magnet insertion step (step S6), and resin hardening step (step S7) can use the same heating device 160 and pressing jig 170. This allows for efficient manufacturing of the motor 1.

[0066] Although each embodiment has been described in detail above, it is not limited to the specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or a plurality of components of the above-described embodiments. [Explanation of symbols]

[0067] 1... motor (rotating electric machine), 30... rotor (rotating electric machine rotor), 32... rotor core, 322... magnet hole, 62... permanent magnet

Claims

1. providing a rotor core having axial magnet holes and permanent magnets insertable into the magnet holes; a resin injection step of injecting a thermosetting resin material having different melting and hardening temperatures in a molten state into the magnet hole; a magnet insertion step of inserting the permanent magnet into the magnet hole in such a manner that the molten resin material reaches around the permanent magnet after the resin injection step; a resin curing step of curing the resin material extending around the permanent magnet inserted in the magnet inserting step, a magnet inserting step and a resin curing step being performed in parallel during a period of time;

2. 2. The method for manufacturing a rotor for a rotating electric machine according to claim 1, further comprising a heat applying step of applying heat to the molten resin material for at least a part of a period from the resin injection step until completion of the magnet insertion step.

3. The method further includes a preheating step of heating the permanent magnet to a temperature equal to or higher than a hardening temperature of the resin material before the magnet insertion step, 3. The method for manufacturing a rotor for a rotating electric machine according to claim 2, wherein the heat application step includes applying heat to the resin material during the magnet insertion step via the permanent magnet heated in the preheating step.

4. The method for manufacturing a rotor for a rotating electric machine according to claim 1 , further comprising a magnetizing step of magnetizing the permanent magnets after the resin curing step is completed.

5. 2. The method for manufacturing a rotor for a rotating electric machine according to claim 1, wherein the resin material has a melt viscosity of 500 Pa·s or more at 90° C. and a shear rate of 1 / s.

6. The method further includes a pressing step of pressing the rotor core in an axial direction to form a pressed state, The method for manufacturing a rotor for a rotating electric machine according to claim 1 , wherein the magnet inserting step is performed in the pressed state.

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