JP7823554B2 - Manufacturing method for rotor for rotating electric machine - Google Patents

Description

This disclosure relates to a method for manufacturing a rotor for a rotating electric machine.

A known method for manufacturing rotors for rotating electrical machines involves inserting a solid resin material into a magnet hole, then inserting a preheated permanent magnet into the magnet hole to melt at least a portion of the resin material, and then further heating the core to harden the resin material.

Japanese Patent Application Laid-Open No. 2018-7565

However, with the above-mentioned 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 within the magnet hole.

Therefore, in one aspect, the present disclosure aims to insert a permanent magnet into a desired position within a magnet hole and fix it with a resin material.

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.

In one aspect, the present disclosure allows a permanent magnet to be inserted into a desired position within a magnet hole and secured in place with a resin material.

1 is a cross-sectional view schematically showing a cross-sectional structure of a motor according to an embodiment. FIG. 2 is a cross-sectional view of the rotor (a cross-sectional view taken along a plane perpendicular to the axial direction). FIG. 3 is an enlarged view of a portion relating to one magnetic pole shown in FIG. 2 . FIG. 4 is a schematic cross-sectional view taken along line AA in FIG. 3. 4 is a flowchart showing an outline of a method for manufacturing a motor according to the present embodiment. FIG. FIG. 10 is an explanatory diagram of a nozzle positioning step. FIG. 10 is an explanatory diagram of a resin injection process. FIG. 10 is an explanatory diagram of a magnet insertion process. 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. FIG. 10 is a schematic cross-sectional view illustrating a resin curing step.

Each embodiment will be described in detail below with reference to the accompanying drawings. Note that the dimensional proportions in the drawings are merely examples and are not intended to be limiting. Furthermore, shapes and other features in the drawings may be partially exaggerated for the sake of explanation.

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

Figure 1 shows the rotating shaft 12 of the 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.

Motor 1 may be a vehicle drive motor used in, for example, a hybrid vehicle or an electric vehicle. However, motor 1 may also be used for any other purpose.

The motor 1 is an inner rotor type, with the stator 21 surrounding the radially outer side of the rotor 30. The radially outer side of the stator 21 is fixed to the motor housing 10. The stator 21 has a stator core 211 made of, for example, a circular annular magnetic laminated steel plate, and multiple slots (not shown) are formed radially inside the stator core 211, around which the coils 22 are wound.

The rotor 30 is positioned radially inward of the stator 21.

The rotor 30 comprises a rotor core 32, a rotor shaft 34, end plates 35A and 35B, and a permanent magnet 62.

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 Figure 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 spline connection. The rotor shaft 34 is rotatably supported in the motor housing 10 via bearings 14a and 14b. The rotor shaft 34 defines the rotating axis 12 of the motor 1.

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

As shown in Figure 2, the rotor core 32 has a rotationally symmetrical shape around the rotation axis 12 when viewed in the axial direction. In the example shown in Figure 2, the rotor core 32 is configured so that each set of permanent magnets 62 overlaps every 45 degrees of rotation around the rotation axis 12.

The multiple permanent magnets 62 may be made of neodymium or the like. In this embodiment, 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 each pair of permanent magnets 62. The multiple permanent magnets 62 are arranged so that south and north poles alternate in the circumferential direction. While 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 other features related to the permanent magnets 62 described below can be similarly applied to other permanent magnets.

Note that while Figure 1 shows a motor 1 with a specific structure, the structure of the motor 1 is not limited to such a specific structure. For example, in Figure 1, the rotor shaft 34 is hollow, but it may also be solid.

Next, the fixing structure of the permanent magnets 62 in the rotor core 32 will be described in detail with reference to Figure 3 and subsequent figures. Below, the configuration related to one magnetic pole will be described, but the configuration related to the other magnetic poles may be similar.

Figure 3 is a plan view showing a schematic representation of the fixed structure of the permanent magnets 62 in the rotor core 32 according to this embodiment, and is an enlarged view of a portion of one magnetic pole shown in Figure 2. The configuration of one magnetic pole is basically symmetrical about the d-axis (written as "d-axis" in English in Figures 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. Figure 4 is a schematic cross-sectional view taken along line A-A in Figure 3.

In Figure 4, the Z direction is defined along with its two opposite sides, the Z1 side and the Z2 side. 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 the Z2 side represent a relative positional relationship, with the Z1 side corresponding to the upper side.

In this embodiment, as shown in Figures 3 and 4, the permanent magnets 62 are fixed in the magnet holes 322 of the rotor core 32 by a resin material layer 72.

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

As shown in FIG. 4, the resin material layer 72 may be bonded to the permanent magnet 62 in a manner that exposes both axial end faces 621, 622 of the permanent magnet 62. 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 intersect the axial direction. However, the material for the resin material layer 72 may be attached to the end face 622 of both axial end faces 621, 622 of the permanent magnet 62.

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 completely fills the space between the permanent magnet 62 and the peripheral wall surface of the magnet hole 322. 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 its entire circumference when viewed in the axial direction. That is, the resin material layer 72 is bonded to all four sides of the permanent magnet 62. Also, 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. That is, 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 more firmly fixed to the rotor core 32 than when the resin material layer is bonded only to a portion of the circumference of the permanent magnet 62.

Next, we will explain the manufacturing method of the motor 1 according to this embodiment, with reference to Figure 5 and subsequent figures.

In the following description, as mentioned 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.

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

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

Next, as shown schematically in FIG. 10, this manufacturing method includes a workpiece supporting step (step S2) in which the workpiece W is placed 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 processes. In this case, the support jig 120 may itself 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.

Next, this manufacturing method includes a preheating step (step S3) in which the workpiece W is preheated. The preheating step may be achieved using 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 using a heating device 160 (see Figures 10 and 11) described below.

Next, as shown schematically in Figure 7, this manufacturing method includes a nozzle positioning process (step S4) in which the nozzle 131 of the resin placement device 130 is positioned 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.

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. The resin material 90 may be molten within a resin injector (not shown) and then introduced into nozzle 131. In the resin injection process, nozzle 131 may eject molten resin material 90 from outlet 1310 while the outlet 1310 is inserted within magnet hole 322. In this case, compared to ejecting (dripping) resin material 90 from outlet 1310 outside magnet hole 322, 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.

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.

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 radically polymerizable composition such as that described in Japanese Patent Application Laid-Open No. 2021-161164, the disclosure of which is incorporated herein by reference.

Furthermore, 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. Note that in this case, during the resin injection process, the resin temperature heated by the resin injection machine (not shown) 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 the resin material 90 starting to harden.

Next, as shown schematically in Figure 9, this manufacturing method includes a magnet insertion process (step S6) in which permanent magnets 62 are placed in the 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 gaps (i.e., a position where they make surface contact).

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 pooling in the lower portion of the magnet hole 322 of the workpiece W (the lower portion when the surface of the support jig 120 is 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 over the same range as the extension range of the resin material layer 72 as described above with reference to Figure 3.

In this embodiment, as described above, the resin material 90 has a relatively low melt viscosity, allowing it to easily and tightly spread around the permanent magnet 62 during the magnet insertion process. In other words, 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 (fixing strength of the permanent magnet 62) provided by the resin material layer 72 formed from the resin material 90.

In this embodiment, the resin material 90 preferably has the property 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 process (step S6), which is performed after the resin injection process (step S5). This allows the resin material 90 to easily and tightly extend around the permanent magnet 62 during the magnet insertion process (step S6).

In this embodiment, the amount V2 (ml) of resin material 90 injected into one magnet hole 322 may be less than the difference between the volume V0 (cm ³ ) of that magnet hole 322 and the volume V1 (cm ³ ) of the permanent magnet 62 inserted into that magnet hole 322 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).

The allowance 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 thermal stress problems. That is, due to the difference in linear expansion coefficients between the permanent magnet 62 and the resin material 90 layer, thermal stress problems arise from the difference in axial expansion and contraction that occurs between the two when the temperature changes. Therefore, by setting the allowance α, thermal stress problems caused by the difference in axial expansion and contraction between the resin material layer 72 and the permanent magnet 62 can be reduced.

In this embodiment, as described above, the magnet insertion process (step S6) is performed while maintaining the resin material 90 in the magnet holes 322 of the workpiece W in a molten state. During the magnet insertion process (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 temperature above its curing temperature, provided that the ease of insertion of the permanent magnets 62 during the magnet insertion process (step S6) is not impaired. In other words, the resin curing process (step S7), described below, may be initiated so as to overlap with the magnet insertion process (step S6). Alternatively, the temperature of the resin material 90 may be controlled so that it does not exceed its curing temperature (e.g., maintained at a temperature significantly lower than the curing temperature) until the magnet insertion process (step S6) is completed.

In the example shown in FIG. 10, the heating device 160, which is one element of the manufacturing apparatus 100, is arranged 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 through 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.

Such a heating device 160 may also function in the resin injection process (step S5). That is, in the resin injection process (step S5), the heating device 160 may apply heat to the resin material 90 poured into the magnet hole 322. In this case, too, the heating device 160 can heat the resin material 90 via the rotor core 32, thereby effectively maintaining the resin material 90 in a molten state.

Furthermore, instead of or in addition to heating by the heating device 160, a preheating step may be separately performed to preheat the permanent magnet 62 to be inserted. For example, a magnet preheating step (step S6A) to preheat the permanent magnet 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 magnet 62 itself. In this case, the magnet preheating step (step S6A) may preferably include heating the permanent magnet 62 to a temperature equal to or higher than the curing temperature of the resin material 90.

When the magnet preheating process (step S6A) is performed, the heat from the permanent magnet 62 causes the resin material 90 to rise above its curing initiation temperature, starting from the portion in contact with the permanent magnet 62. In other words, the portion of the resin material 90 in contact with the permanent magnet 62 reaches the curing initiation temperature or higher, and thermal curing begins. In this case, the magnet insertion process is completed before the time it takes for the resin material 90 to cure (completely gel) (gel time or gelation time). This allows for 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. Positional stability of the permanent magnet 62 is achieved by increasing the viscosity of the resin material 90 around the permanent magnet 62, making it more difficult for the permanent magnet 62 to move.

Even when the resin material 90 is a thermoplastic resin material, the rotor core 32, etc., can be heated (or preheated using the preheating process described above) to maintain the resin material 90 in a molten state during the magnet insertion process (step S6). Furthermore, when the resin material 90 is a thermoplastic resin material, the temperature of the resin material 90 during the resin injection process (step S5) may be set relatively high. Even when the resin material 90 is a thermoplastic resin material, appropriately setting the temperature of the resin material 90 during the magnet insertion process (step S6) can achieve both ease of insertion of the permanent magnet 62 (ease of positioning the permanent magnet 62 at the desired position within the magnet hole 322) and positional stability of the positioned permanent magnet 62.

In this embodiment, the resin material 90 has a relatively low melt viscosity as described above, which makes it more likely to leak from between the steel plates 3250 than if the resin material had a relatively high melt viscosity. In this embodiment, the resin material 90 is not pressurized within the magnet holes 322, reducing the likelihood of the resin material 90 leaking from between the steel plates 3250. Specifically, the magnet insertion process (step S6) is performed with the magnet holes 322 of the workpiece W open to atmospheric pressure. This significantly reduces the likelihood of the resin material 90 leaking from between the steel plates 3250 during 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, reducing the likelihood of the resin material 90 leaking from between the steel plates 3250.

Alternatively, in this embodiment, taking into consideration that the resin material 90 has a relatively low melt viscosity, the rotor core 32 may be pressed in the axial direction during the magnet insertion process (step S6). In other words, the magnet insertion process (step S6) may be performed together with the pressing process in which the rotor core 32 is pressed in the axial direction.

In the example shown in FIG. 10, the manufacturing apparatus 100 has a pressing jig 170 that applies axial force to the rotor core 32. In this case, the pressing jig 170 can press from above against the workpiece W on the support jig 120 (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 a hole 172 that opens the top of the magnet hole 322. In this case, the permanent magnet 62 can be inserted while maintaining the pressing state of the pressing jig 170 against the rotor core 32.

Such a pressing jig 170 may also function in the resin injection process (step S5). That is, in the resin injection process (step S5), resin material 90 may be placed in the magnet hole 322 under pressure from the pressing jig 170. In this case, the possibility of resin material 90, which has a relatively low melt viscosity, leaking out from between the steel plates 3250 can be reduced from the resin injection process (step S5) stage. In this case, the resin injection process (step S5) may be performed using the hole 172 of the pressing jig 170.

Next, this manufacturing method includes a resin curing process (step S7) in which the resin material 90 injected into the magnet hole 322 is cured. The resin curing process (step S7) includes heating 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 process (step S7) includes cooling the molten resin material 90 to a temperature equal to or lower than the curing temperature.

As described above, the resin curing process (step S7) may overlap with the magnet insertion process (step S6) in such a way that the magnet insertion process (step S6) is completed before the resin curing process (step S7). That is, the resin curing process (step S7) may be performed in parallel with the magnet insertion process (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 process (step S5). That is, part of the resin curing process (step S7) may be performed in the resin injection process (step S5).

Here, thermosetting resin, suitable for use as 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 rises sharply due to a crosslinking reaction, or in other words, a transition 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 exceeds the complete curing time. When using a thermosetting resin, the completion of the resin curing process (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 process (step S7) is performed in parallel with the magnet insertion process (step S6), the magnet insertion process (step S6) only needs to be completed by the time gelation is complete. In this case, the time required from the start of the magnet insertion process (step S6) to the completion of the resin curing process (step S7) can be shortened.

Furthermore, when the above-mentioned preheating process (step S3) or magnet preheating process (step S6A) is performed, the resin curing process (step S7) may be achieved using only these heat sources. In other words, the resin curing process (step S7) does not require the application of new thermal energy (further heating). In particular, when the magnet preheating process (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 (rotor core 32 with permanent magnets 62 inserted) is moved for further heating, for example, displacement of the permanent magnets 62 due to such movement can be prevented.

In the example shown in FIG. 11, the heating device 160, which is one element of the manufacturing apparatus 100, is arranged radially inside and outside the rotor core 32 of the workpiece W, and can heat and harden 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.

The resin curing process (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 has 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 will experience when assembling the rotor 30 using the rotor core 32 in the subsequent step S9. The axial force that the rotor core 32 will experience when assembling the rotor 30 may correspond, for example, to the axial force generated by being clamped between the end plates 35A and 35B (see force F10 in FIG. 1). In this case, the magnitude of the axial force F92 may correspond to the design or measured value of the magnitude of the axial force F10. Note that design values do not necessarily have to be values written on design drawings, but are a concept that includes suitable values and target values obtained in the design through analysis, etc.

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 is applied to the rotor core 32 when assembling the rotor 30.

Next, this manufacturing method includes a magnetization process (step S8) in which the permanent magnet 62 is magnetized. Note that, when performing the magnet preheating process (step S6A), the permanent magnet 62 will be heated before the magnetization process (step S8), but this heating does not substantially affect the magnetization characteristics or the magnetic properties after magnetization. Note that the magnetization process (step S8) may also be performed at an earlier stage (for example, before the magnet insertion process or magnet preheating process).

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 axial force F10 (see Figure 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) along with the stator 21 and other components, and the motor 1 is assembled.

As described above, according to this manufacturing method, 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 the 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 the desired position within the magnet hole 322 and fixed in place by the resin material 90.

Furthermore, with this manufacturing method, a common heating device 160 and pressing jig 170 can be used for the magnet insertion process (step S6), or for the resin injection process (step S5), magnet insertion process (step S6), and resin hardening process (step S7). This enables efficient manufacturing of the motor 1.

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

1... Motor (rotating electric machine), 30... Rotor (rotating electric machine rotor), 32... Rotor core, 322... Magnet hole, 62... Permanent magnet

Claims (6)

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 ; The method for manufacturing a rotor for a rotating electric machine according to claim 1, further comprising a heat application step of applying heat to the molten resin material for at least a portion of the period from the resin injection step until the magnet insertion step is completed. 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. The method for manufacturing a rotor for a rotating electric machine according to any one of claims 1 to 3, further comprising a magnetizing step of magnetizing the permanent magnets after the resin curing step is completed. 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. 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.