Method for manufacturing a rotor for a rotating electric machine and a rotor for a rotating electric machine

Abstract

The present invention provides a method for manufacturing a rotor for a rotating electric machine that reduces the preheating time, or a rotor for a rotating electric machine having a structure that enables a reduction in preheating time. [Solution] A method for manufacturing a rotor for a rotating electric machine is disclosed, comprising the steps of: preparing a rotor core having an annular shape when viewed in the axial direction and having axial magnet holes and axial first through holes; an injection step of injecting a first molten material, which has been brought to a molten state by heating, into the first through holes; and a magnet placement step of injecting a second molten material, which has been brought to a molten state by heating, into the magnet holes after the injection step, thereby arranging permanent magnets in the magnet holes, wherein the magnet placement step includes fixing the magnets for permanent magnets inserted into the magnet holes in the magnet holes as the second molten material hardens, or forming bonded magnets for permanent magnets in the magnet holes as the second molten material containing magnet powder hardens.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a rotor for a rotating electrical machine and a rotor for a rotating electrical machine.

Background Art

[0002] A technique of injecting a molten resin material into a magnet hole of a rotor core to fix a permanent magnet in the magnet hole is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the process of injecting a molten resin material into a rotor core, when the resin material is a thermosetting resin, preheating of the rotor core is required for curing, and when the resin material is a thermoplastic resin, preheating of the rotor core is required to enhance fluidity. As such a preheating method, for example, there is a method of applying heat to the outside (periphery) of the rotor core by a heating device while sandwiching the rotor core between an upper mold and a lower mold.

[0005] However, in the above-described preheating method, it takes a relatively long time for heat transfer to the inside of the rotor core, and it is difficult to reduce the preheating time.

[0006] Therefore, on one hand, an object of the present disclosure is to reduce the preheating time in a method for manufacturing a rotor for a rotating electrical machine and to provide a rotor for a rotating electrical machine having a structure capable of reducing the preheating time.

Means for Solving the Problems

[0007] One aspect involves preparing a rotor core having an annular shape when viewed in the axial direction, and having an axial magnet hole and a first through hole in the axial direction. An injection step in which the first molten material, which has been brought to a molten state by heating, is injected into the first through hole, The process includes a magnet placement step in which, after the injection step, a second molten material, which has been heated to a molten state, is injected into the magnet hole to place a permanent magnet in the magnet hole. A method for manufacturing a rotor for a rotating electric machine is provided, wherein the magnet arrangement step includes fixing the magnets for the permanent magnets inserted into the magnet holes as the second molten material hardens, or forming bonded magnets for the permanent magnets in the magnet holes as the second molten material containing magnet powder hardens. [Effects of the Invention]

[0008] In one respect, this disclosure makes it possible to reduce the preheating time in a method for manufacturing a rotor for a rotating electric machine, or to provide a rotor for a rotating electric machine having a structure that enables a reduction in preheating time. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic cross-sectional view showing the cross-sectional structure of a motor according to one embodiment. [Figure 2] This is a perspective view of the rotor with the end plate and nut removed. [Figure 3] This is a perspective view of the end plate from the axial outside. [Figure 4] This is a perspective view of the end plate, seen from the axial inner side. [Figure 5] This is a perspective view showing the end plate integrated with the rotor shaft. [Figure 6] This is a schematic flowchart illustrating one example of a rotor manufacturing method. [Figure 7] This is a plan view of the workpiece as seen axially from the end plate side. [Figure 8] This is a cross-sectional view of a portion of the workpiece passing through a single through-hole. [Figure 9] This is an enlarged view of section Q9 in Figure 8. [Figure 10] This diagram illustrates the positional relationship between the workpiece on the transport mechanism and the two injection molding machines during the resin injection process. [Figure 11] This diagram illustrates the positional relationship between the workpiece on the transport mechanism and the two injection molding machines during the magnet fixing process. [Figure 12] This is a schematic flowchart illustrating another example of a rotor manufacturing method. [Modes for carrying out the invention]

[0010] The following describes each embodiment in detail with reference to the attached drawings. Note that the dimensional ratios in the drawings are merely examples and are not exhaustive. Furthermore, shapes and other details in the drawings may be partially exaggerated for illustrative purposes. Also, for clarity, in some cases, only a portion of parts with the same attribute are assigned reference numerals in the drawings.

[0011] Figure 1 is a schematic cross-sectional view showing the cross-sectional structure of motor 1 according to one embodiment. Figure 2 is a perspective view of rotor 30 with end plate 35A and nut 36 removed. Note that in Figure 2 and other figures, for ease of viewing, only some of the parts with the same attributes that exist in multiple locations may be assigned reference numerals.

[0012] Figure 1 shows the rotation axis 12 of motor 1. In the following explanation, axial direction refers to the direction in which the rotation axis (center of rotation) 12 of motor 1 extends, and radial direction refers to the radial direction centered on the rotation axis 12. Therefore, radially outward refers to the side away from the rotation axis 12, and radially inward refers to the side toward the rotation axis 12. Furthermore, circumferential direction corresponds to the direction of rotation around the rotation axis 12.

[0013] Motor 1 may be, for example, a vehicle drive motor used in hybrid vehicles or electric vehicles. However, Motor 1 may be used for any other purpose.

[0014] The motor 1 is, for example, an inner rotor type, and the stator 21 is provided so as to surround the outer side in the radial direction of the rotor 30. The outer side in the radial direction of the stator 21 is fixed to the motor housing 10. The stator 21 includes, for example, a stator core 211 made of a laminated steel sheet of an annular magnetic material, and a plurality of slots (not shown) around which the coil 22 is wound are formed on the inner side in the radial direction of the stator core 211.

[0015] The rotor 30 is disposed on the inner side in the radial direction of the stator 21.

[0016] The rotor 30 includes a rotor core 32, a rotor shaft 34, end plates 35A and 35B, nuts 36, permanent magnets 61 and 62, and a resin material portion 70.

[0017] The rotor core 32 is fixed to the surface on the outer side in the radial direction of the rotor shaft 34 and rotates integrally with the rotor shaft 34. The rotor core 32 has a shaft hole 320 (see FIG. 2), and the rotor shaft 34 is fitted into the shaft hole 320. Note that the rotor core 32 and the rotor shaft 34 may be coupled in a manner having a radial tightening allowance by a coupling method such as press fitting or shrink fitting. Further, the rotor core 32 and the rotor shaft 34 may be coupled in a manner that no relative displacement occurs in the rotational direction by using an axial key and key groove.

[0018] The rotor shaft 34 is rotatably supported by the motor housing 10 via bearings 14a and 14b. The rotor shaft 34 defines the rotation axis 12 of the motor 1. In the illustrated example, the rotor shaft 34 has a hollow shape, but may be solid. Further, the rotor shaft 34 has a constant diameter, but may have a step in the radial direction.

[0019] ]The rotor core 32 is formed, for example, from laminated steel plates of annular magnetic material. In a modified example, the rotor core 32 may be formed from compacted magnetic powder. Permanent magnets 61 and 62 (see Figure 2) are arranged inside the rotor core 32. That is, the rotor core 32 has magnet holes 321 and 322 (see Figure 2) that penetrate in the axial direction, and the permanent magnets 61 and 62 are formed within the magnet holes 321 and 322.

[0020] In this embodiment, the rotor core 32 has through holes 324 that penetrate in the axial direction. The through holes 324 are formed radially inward from the magnet holes 321 and 322. Multiple through holes 324 are formed at the same radial position with a predetermined circumferential pitch. In this case, each through hole 324 is formed in such a manner that it has the same positional relationship with respect to the nearest magnet holes 321 and 322. In this embodiment, the through holes 324 are arranged to be located on each q-axis. In modified examples, they may be arranged at other positions (for example, on the d-axis) instead of or in addition to the q-axis. In modified examples, a larger number of through holes 324 may be formed at different radial positions in an arrangement of two or more layers.

[0021] As shown in Figure 2, the rotor core 32 has a rotationally symmetrical configuration with respect to the rotation axis 12 when viewed in the axial direction. In the example shown in Figure 2, the rotor core 32 has a configuration in which the magnet holes 321, 322 and the through hole 324 overlap each time the rotor core 32 rotates 45 degrees around the rotation axis 12.

[0022] The end plates 35A and 35B cover both axial ends of the rotor core 32 in the axial direction. The end plates 35A and 35B also block the magnet holes 321 and 322 in the axial direction. In this embodiment, the end plate 35B is integrally formed with the rotor shaft 34, but it may be a separate component. The characteristic configurations of the end plates 35A and 35B will be described later.

[0023] The nut 36 is fastened to the rotor shaft 34. The nut 36 faces the axial end face of the rotor core 32 via the end plate 35A. The nut 36 may generate an axial force between the end plate 35A and the end plate 35B.

[0024] The permanent magnets 61 and 62 are formed by sintering, but may also be formed by bonding. In the case of sintering, each of the multiple permanent magnets 61 and 62 is fixed in the magnet holes 321 and 322 with a resin material. The injection molding method of the resin material in this case is arbitrary and may include, for example, transfer molding or resin injection by compression molding using a cylinder. On the other hand, in the case of bonding, each of the multiple permanent magnets 61 and 62 is formed by injection molding a bonding material (hereinafter also simply referred to as "bonding magnet material") which is a mixture of magnet powder and a binder. The injection molding method in this case is also arbitrary and may include, for example, transfer molding or resin injection by compression molding using a cylinder.

[0025] In the example shown in Figure 2, the multiple permanent magnets 61 and 62 are arranged in a roughly V-shape (a roughly V-shape with the radially outward side opening) with pairs of two types of permanent magnets 61 and 62 when viewed in the axial direction. In this case, a common magnetic pole is formed between the pairs of permanent magnets 61 and between the pairs of permanent magnets 62. The multiple permanent magnets 61 and 62 are arranged in a manner in which the south poles and north poles alternate in the circumferential direction. In this embodiment, there are eight magnetic poles, but the number of magnetic poles is arbitrary. Also, in the example shown in Figure 2, the permanent magnets 61 and 62 are arranged in two layers at different radial positions, but they may be arranged in only one layer, and the arrangement of the magnets is arbitrary.

[0026] The resin material portion 70 is formed by injecting a resin material, which has been molten by heating, into the through hole 324. In this case, the resin material that hardens within the through hole 324 forms the resin material portion 70. As will be described later, the resin material portion 70 functions as a heat source when preheating the rotor core 32 during the manufacturing of the rotor 30. Therefore, the resin material portion 70 does not need to have any particular function in the rotor 30 in its finished state, but it may have a function in relation to the end plates 35A and 35B, as will be described later. Details of the resin material portion 70 will be described later.

[0027] Here, with reference to Figures 3 to 5, preferred configurations of end plates 35A and 35B will be described.

[0028] Figure 3 is a perspective view of the end plate 35A viewed from the axial outside, Figure 4 is a perspective view of the end plate 35A viewed from the axial inside, and Figure 5 is a perspective view showing the end plate 35B integrated with the rotor shaft 34.

[0029] In this embodiment, an axial through hole 352A is formed in the end plate 35A, and an axially oriented bottomed hole 352B is formed in the end plate 35B. The axially oriented bottomed hole 352B is formed on the axially inward side (the side facing the end plate 35A).

[0030] The through-hole 352A and the closed-end hole 352B are formed at positions corresponding to the through-hole 324 of the rotor core 32. That is, the through-hole 352A and the closed-end hole 352B are provided along the circumferential direction in such a manner that they overlap with the respective through-holes 324 of the rotor core 32 when viewed in the axial direction. Therefore, the through-hole 352A and the closed-end hole 352B are continuous in the axial direction with respect to the corresponding through-hole 324. In this embodiment, the resin material portion 70 extends not only to the through-hole 324 but also to the through-hole 352A and the closed-end hole 352B. That is, the resin material portion 70 extends continuously from within the through-hole 324 into the through-hole 352A and the closed-end hole 352B. In this case, the rotor core 32 and the end plates 35A and 35B can be connected via the resin material portion 70. This makes it possible to transmit rotational torque around the rotation axis 12 between the rotor core 32 and the end plates 35A and 35B. Therefore, for example, when the rotor core 32 and the rotor shaft 34 are key-fitted, the resin material portion 70 can restrict the rotational freedom of the end plate 35A relative to the rotor core 32. Also, as in this embodiment, when the end plate 35B is integrated with the rotor shaft 34, the resin material portion 70 can increase the transmissionable rotational torque between the rotor core 32 and the rotor shaft 34.

[0031] In this embodiment, as will be described later, the resin material is injected into the magnet holes 321 and 322 with the end plate 35A assembled to the rotor core 32. For this reason, the end plate 35A has a port hole 354A for injecting the resin material and a cavity 355A around the port.

[0032] Next, with reference to Figure 6 and subsequent figures, preferred embodiments of the method for manufacturing the rotor 30 will be described.

[0033] Figure 6 is a schematic flowchart showing an example of a method for manufacturing the rotor 30. Figure 6 relates to a manufacturing method when the permanent magnets 61 and 62 are formed by sintered magnets. Figures 7 to 9 are explanatory diagrams of the heat transfer manner from the preheating resin material to the rotor core 32. Figure 7 is a plan view of the workpiece W viewed axially from the end plate 35A side, and Figure 8 is a cross-sectional view of a part of the workpiece W passing through one through hole 324, with a part of the mold device 100 also shown. Figure 9 is an enlarged view of part Q9 in Figure 8. Figures 10 and 11 are explanatory diagrams of the positional relationship between the workpiece W being transported on the transport means 950 and the two injection molding machines 951 and 952. Figure 10 shows the positional relationship in the resin injection process (step S604), and Figure 11 shows the positional relationship in the magnet fixing process (step S605).

[0034] This manufacturing method first includes a step (step S600) of preparing the materials used in this manufacturing method for the various components that make up the rotor 30 (rotor core 32, rotor shaft 34, end plate 35A, etc.). Although the material for the rotor core 32 may not be exactly the same as the rotor core 32 in the finished product (for example, its physical properties may differ due to the effects of heating, etc.), it will be simply referred to as "rotor core 32" below, and the same applies to the materials for the other components.

[0035] Next, this manufacturing method includes a step (step S601) of inserting sintered magnets relating to permanent magnets 61 and 62 into the magnet holes 321 and 322 of the rotor core 32 assembled to the rotor shaft 34 (and end plate 35B).

[0036] Next, this manufacturing method includes a step (step S602) of assembling the end plate 35A and the nut 36 onto the rotor core 32. Hereinafter, the assembly formed by such assembly will also be simply referred to as "workpiece W".

[0037] Next, this manufacturing method includes the step of setting the workpiece W in an injection molding device 100 (partially shown in Figure 8) and closing and tightening the mold device 100 (step S603). The configuration of the mold device 100 itself is arbitrary and only needs to be configured to enable the injection of the resin material described later.

[0038] Next, this manufacturing method includes a resin injection step (step S604) in which a preheating resin material (molten by heating) (an example of a first molten material) is injected through a through hole 352A in the end plate 35A. The resin material injected into the through hole 352A fills the through hole 324 of the rotor core 32 and also reaches the bottomed hole 352B of the end plate 35B. In the example shown in Figure 8, the mold device 100 has a runner plate 102 assembled to the workpiece W, and resin material (indicated by the hatched area M8 in Figure 8) is injected via a heater-equipped main runner 103.

[0039] When this molten resin material is filled into the rotor core 32, the heat from the resin material is transferred from the inside of the rotor core 32 to the entire rotor core 32. Specifically, as schematically shown by arrow R7 in Figure 7, the heat from the resin material from each through-hole 324 is transferred radially. In this case, since multiple through-holes 324 are arranged along the circumferential direction, the radially outer side of the rotor core 32 can be heated over the entire circumferential direction. Furthermore, as schematically shown by arrow R9 in Figure 9, this radial transfer of heat occurs over the entire axial direction of the rotor core 32. In this way, according to this manufacturing method, the entire rotor core 32 can be efficiently heated (preheated) by the heat from the molten resin material injected into the through-holes 324.

[0040] Incidentally, when the rotor core 32 is formed by laminating electrical steel sheets, an insulating coating is formed on each electrical steel sheet. Since such an insulating coating reduces the heat transfer properties of the rotor core 32, when the rotor core 32 is heated from the outside (surroundings), the time required to raise the temperature of the inside of the rotor core 32 to the desired temperature tends to be relatively long.

[0041] In contrast, according to this manufacturing method, the rotor core 32 can be efficiently heated from the inside by the heat from the resin material filled inside the rotor core 32. Furthermore, since there is no insulating coating on the peripheral wall of the through hole 324, the rotor core 32 can be efficiently heated in a manner that is less affected by the insulating coating (see arrow R9 in Figure 9). In this way, according to this embodiment, the time required to raise the temperature of the inside of the rotor core 32 to the desired temperature can be significantly reduced.

[0042] Furthermore, since the through-holes 324 are holes for receiving such preheating resin material into the rotor core 32, the number and size of the through-holes 324 (the total capacity of the through-holes 324) may be adjusted according to the thermal energy required for preheating.

[0043] Next, this manufacturing method includes a magnet fixing step (step S605) in which a resin material for fixing magnets (in a molten state upon heating) (an example of a second molten material) is injected through the port hole 354A of the end plate 35A around the permanent magnets 61 and 62 in the magnet holes 321 and 322. Preferably, the magnet fixing step (step S605) is performed after a predetermined time has elapsed from the end of the preceding resin injection step (step S604) (when the injection of the resin material is completed). The predetermined time may correspond to the time required for the heat from the resin material to spread throughout the rotor core 32 (i.e., the time required for preheating). In this case, the magnet fixing step (step S605) can be performed when the rotor core 32 heated in the resin injection step (step S604) is at the desired temperature. This ensures the necessary fluidity of the resin material for fixing magnets within the magnet holes 321 and 322 during the magnet fixing step (step S605).

[0044] For example, as shown in Figures 10 and 11, the resin injection process (step S604) and the magnet fixing process (step S605) may be performed sequentially and continuously on a workpiece W being transported on a transport means 950 such as a conveyor. In this case, as shown in Figures 10 and 11, the injection molding machine 951 for the resin injection process (step S604) and the injection molding machine 952 for the magnet fixing process (step S605) may be arranged adjacent to each other in the transport direction of the transport means 950 (see arrow R100 in Figures 10 and 11), starting from the upstream side. This allows the resin injection process (step S604) and the magnet fixing process (step S605) to be efficiently performed sequentially while the workpiece W is being transported by the transport means 950. In this case, the predetermined time (preferred interval from step S604 to step S605) described above can be easily achieved by adjusting the transport speed of the workpiece W by the transport means 950. In other words, by utilizing the predetermined time required for preheating, the workpiece W can be moved by the transport means 950 to a position where the next process, the magnet fixing process (step S605), can be performed, thereby reducing the cycle time.

[0045] Alternatively, in a modified version, the workpiece W may not be moved between the resin injection process (step S604) and the magnet fixing process (step S605). For example, the resin injection process (step S604) and the magnet fixing process (step S605) may be performed while the workpiece W remains fixed by moving the injection molding machine 951 and the injection molding machine 952, or by using a common injection molding machine. In this case, the temperature drop of the rotor core 32 caused by the movement of the workpiece W can be suppressed.

[0046] Furthermore, this manufacturing method includes a step (step S606) for curing the resin material injected in the magnet fixing step (step S605). The resin material injected in the resin injection step (step S604) may be cured using the predetermined time described above, or it may be cured at the same time as the curing of the resin material injected in the magnet fixing step (step S605).

[0047] In this manufacturing method, the resin material injected in the resin injection step (step S604) may be the same as or different from the resin material injected in the magnet fixing step (step S605).

[0048] Next, this manufacturing method includes the step of opening the mold device 100 and removing the workpiece W (step S607).

[0049] In this way, according to this manufacturing method, by performing the resin injection process (step S604) prior to the magnet fixing process (step S605), the resin injection process (step S604) can be used as a preheating process. This makes it possible to perform the preheating process that should be carried out prior to the magnet fixing process (step S605) without using heating devices or furnaces that heat the rotor core 32 from around. Alternatively, it is possible to simplify the preheating process that heats the rotor core 32 from around (for example, by shortening the preheating time or miniaturizing the heating device).

[0050] Figure 12 is a schematic flowchart showing another example of a method for manufacturing the rotor 30. Figure 12 relates to a manufacturing method in which the permanent magnets 61 and 62 are formed by bonded magnets.

[0051] This manufacturing method first includes a step (step S1200) of preparing the materials used in this manufacturing method, which are the various components that make up the rotor 30 (rotor core 32, rotor shaft 34, end plate 35A, etc.).

[0052] Next, this manufacturing method includes a step (step S1201) of assembling the end plate 35A and the nut 36 onto the rotor core 32. Hereinafter, the assembly formed by such assembly will also be simply referred to as "workpiece W".

[0053] Next, this manufacturing method includes the step of setting the workpiece W in an injection molding device 100 (partially shown in Figure 8) and closing and tightening the mold device 100 (step S1202). The configuration of the mold device 100 itself is arbitrary and can be any configuration that enables the injection of resin material, as described later.

[0054] Next, this manufacturing method includes a resin injection step (step S1203) in which a preheating resin material (molten by heating) is injected into the through hole 324 of the rotor core 32 through the through hole 352A of the end plate 35A, similar to step S604 in Figure 6. The resin material injected into the through hole 324 fills the through hole 324 of the rotor core 32 and also reaches the bottomed hole 352B of the end plate 35B.

[0055] When this molten resin material is filled into the rotor core 32, the heat from the resin material is transferred from the inside of the rotor core 32 to the entire rotor core 32, as described above with reference to step S604 in Figure 6. In this way, this manufacturing method also allows the entire rotor core 32 to be efficiently heated (preheated) by the heat from the molten resin material injected into the through hole 324.

[0056] Next, this manufacturing method includes a magnet molding step (step S1204) in which bonded magnet material (in a molten state due to heating) is injected into magnet holes 321 and 322 through port holes 354A of the end plate 35A. Preferably, the magnet molding step (step S1204) is performed after a predetermined time has elapsed from the end of the preceding resin injection step (step S1203) (when the injection of the resin material is completed). The predetermined time may correspond to the time required for the heat from the resin material to spread throughout the rotor core 32 (i.e., the time required for preheating), as described above with reference to steps S604 and S605 in Figure 6. In this manufacturing method as well, as in the manufacturing method described above with reference to Figure 6, the resin injection step (step S1203) and the magnet molding step (step S1204) may be performed sequentially and continuously on a workpiece W being transported on a transport means 950 such as a conveyor, as shown in Figures 10 and 11. Alternatively, in a modified version, the workpiece W may not be moved between the resin injection process (step S1203) and the magnet molding process (step S1204).

[0057] Furthermore, this manufacturing method includes a step (step S1205) for curing the resin material injected in the magnet molding step (step S1204). The resin material injected in the resin injection step (step S1203) may be cured using the predetermined time mentioned above, or it may be cured at the same time as the curing of the resin material injected in the magnet molding step (step S1204).

[0058] In this manufacturing method, the resin material injected in the resin injection step (step S1203) may be the same as or different from the resin material injected in the magnet molding step (step S1204).

[0059] Next, this manufacturing method includes the step of opening the mold device 100 and removing the workpiece W (step S1206).

[0060] In this way, this manufacturing method also produces the same effects as the manufacturing method described above, with reference to Figure 6.

[0061] Although each embodiment has been described in detail above, the invention is not limited to any particular embodiment, and various modifications and changes are possible within the scope described in the claims. Furthermore, it is possible to combine all or more of the components of the embodiments described above.

[0062] For example, in the above-described embodiment, a metal material portion may be provided instead of the resin material portion 70. In this case, the metal material portion can be formed by injecting molten metal material into the workpiece W in the same manner as when forming the resin material portion 70, using the same process as when forming the resin material portion 70. In this case as well, preheating can be achieved using the molten metal material, thus providing the same effects as in the above-described embodiment.

[0063] Furthermore, in the above-described embodiment, when the permanent magnets 61 and 62 are formed by bonded magnets, the bonded magnets are formed by injecting bonded magnet material (in a molten state due to heating) into the magnet holes 321 and 322, as shown in Figure 12, but are not limited to this. Bonded magnets formed and solidified externally (outside of the magnet holes 321 and 322) may also be used. In this case, the externally solidified bonded magnets may be fixed to the magnet holes 321 and 322 in the same manner as sintered magnets.

[0064] Furthermore, in the above-described embodiment, the resin material injected in the resin injection process (step S1203) is blocked by the bottomed hole 352B of the end plate 35B, but it may be configured to allow flow from the bottomed hole 352B to the discharge port. In this case, the amount of resin material that can be injected in the resin injection process (step S1203) can be increased, and the thermal energy for preheating can be increased. In such a configuration, the resin material injected in the resin injection process (step S1203) preferably has a higher melting point than the resin material injected in the magnet molding process (step S1204). This is because if the melting point of the resin material injected in the resin injection process (step S1203) is also low, there is a possibility that some of the resin material may flow out from the through hole 324 during the magnet molding process (step S1204).

[0065] Furthermore, in the above-described embodiment, the end plate 35B has a bottomed hole 352B, but instead of the bottomed hole 352B, it may have a through hole. In such a configuration, the resin material injected in the resin injection process (step S1203) preferably has a higher melting point than the resin material injected in the magnet molding process (step S1204). This is because if the melting point of the resin material injected in the resin injection process (step S1203) is also low, there is a possibility that some of the resin material may flow out from the through hole 324 during the magnet molding process (step S1204). If the melting point of the resin material injected in the resin injection process (step S1203) is higher than the melting point of the resin material injected in the magnet molding process (step S1204), the resin material injected in the resin injection process (step S1203) will not melt due to the temperature of the rotor core 32 caused by the magnet molding process (step S1204) and will remain in the through hole 324.

[0066] Furthermore, in the above-described embodiment, the resin injection process (step S1203) can be performed without the need for a core preheating process using another heating device. However, in the modified version, it may be performed in cooperation with such a core preheating process. In this case, the other heating device may be provided around the rotor core 32 and heat the rotor core 32 from the outside (around) of the rotor core 32. The other heating device may also be in the form of a furnace.

[0067] Furthermore, in the above-described embodiment, the resin material is injected into the magnet holes 321 and 322 with the end plate 35A assembled to the rotor core 32, but the invention is not limited to this. In this case, the end plate 35A may not have a through hole 352A and may be assembled immediately before the magnet fixing process (step S605) or the magnet molding process (step S1204). Alternatively, the end plate 35A may not have a port hole 354A for injecting the resin material or a cavity 355A around the port and may be assembled after the magnet fixing process (step S605) or the magnet molding process (step S1204).

[0068] Furthermore, in the embodiment described above, the end plate 35B is formed integrally with the rotor shaft 34, but it may also be formed separately from the rotor shaft 34. [Explanation of symbols]

[0069] 30 Rotor, 32 Rotor core, 321, 322 Magnet holes, 324 Through hole (first through hole), 61, 62 Permanent magnets, 35A, 35B End plates, 352A Through hole (second through hole), 352B Bottomed hole, 70 Resin material part (hardened material part)

Claims

1. A step of preparing a rotor core having an annular shape when viewed in the axial direction, and having an axial magnet hole and a first through hole in the axial direction, An injection step in which the first molten material, which has been brought to a molten state by heating, is injected into the first through hole, The process includes a magnet placement step in which, after the injection step, a second molten material, which has been heated to a molten state, is injected into the magnet hole to place a permanent magnet in the magnet hole. A method for manufacturing a rotor for a rotating electric machine, wherein the magnet arrangement step includes fixing the magnets for the permanent magnets inserted into the magnet holes within the magnet holes as the second molten material hardens, or forming bonded magnets for the permanent magnets within the magnet holes as the second molten material containing magnet powder hardens.

2. The method for manufacturing a rotor for a rotating electric machine according to claim 1, wherein the magnet placement step is performed while the temperature of the rotor core has risen due to the heat from the first molten material injected in the injection step.

3. The method for manufacturing a rotor for a rotating electric machine according to claim 1, wherein the melting point of the first molten material is higher than the melting point of the second molten material.

4. A step of preparing an end plate having a second through hole or bottomed hole in the axial direction, The process further includes a setting step of setting the end plate on the axial end face of the rotor core such that the second through hole or bottomed hole of the end plate overlaps with the first through hole of the rotor core when viewed in the axial direction, The method for manufacturing a rotor for a rotating electric machine according to claim 1, wherein the injection step is performed after the setting step and includes pouring the first molten material into the second through hole or bottomed hole.

5. The method for manufacturing a rotor for a rotating electric machine according to any one of claims 1 to 4, wherein the rotor core is formed by stacking a plurality of steel plates in the axial direction.

6. A rotor core having an annular shape when viewed in the axial direction, and having an axial magnetic hole and a first through hole in the axial direction, A sintered magnet fixed in the magnet hole with a fixing resin or a bonded magnet placed in the magnet hole, A rotor for a rotating electric machine, comprising a material hardening section formed in the first through-hole, where the molten material, brought to a molten state by heating, hardens.

7. The rotor core is further provided with an end plate positioned on its axial end face and having a second through hole or a bottomed hole in the axial direction, When viewed in the axial direction, the first through hole of the rotor core and the second through hole or bottomed hole of the end plate overlap. The rotor for a rotating electric machine according to claim 6, wherein the material hardened portion is formed continuously in the axial direction in the first through hole and the second through hole or bottomed hole.

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