Manufacturing apparatus for rotors for rotating electric machines and manufacturing apparatus for rotors for rotating electric machines

Abstract

To manufacture a rotor for a rotary electric machine, in such a form as to reduce stress that can be generated in a cured product (resin material layer) of a resin material in a magnet hole.SOLUTION: A method for manufacturing a rotor for a rotary electric machine includes: a step of preparing a rotor core having a magnet hole, in which a permanent magnet is arranged in the magnet hole; a resin arrangement step of arranging a resin material in a state before curing in the magnet hole of the rotor core; and a resin curing step of curing the resin material while pressing the rotor core in an axial direction, after the resin arrangement step.SELECTED DRAWING: Figure 17

Description

Technical Field

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

Background Art

[0002] There is known a technique of filling a resin material into magnet holes of a rotor core in a form of a laminated iron core in which a plurality of steel plates are laminated, while pressing the rotor core with an upper and lower mold with a predetermined pressure (injection pressure).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the prior art as described above, there may be a significant difference (for example, divergence) between the axial pressing force that can be applied to the rotor core when curing the resin material filled in the magnet holes and the axial pressing force applied to the rotor core in the mounted state (the state of the rotating electric machine). When such a significant difference occurs, in the mounted state, stress may be generated in the cured product (resin material layer) of the resin material in the magnet holes, leading to a risk of strength reduction.

[0005] Therefore, on one side, an object of the present disclosure is to manufacture a rotor for a rotating electric machine in a manner capable of reducing stress that may occur in a cured product (resin material layer) of the resin material in the magnet holes in the mounted state.

Means for Solving the Problems

[0006] On one side, a step of preparing a rotor core having magnet holes, in which a permanent magnet is disposed in the magnet holes, A resin placement step involves placing a resin material in the magnet hole of the rotor core in an uncured state, A method for manufacturing a rotor for a rotating electric machine is provided, which includes a resin curing step in which the rotor core is pressed in the axial direction and the resin material is cured after the resin placement step. [Effects of the Invention]

[0007] In one aspect, this disclosure makes it possible to manufacture a rotor for a rotating electric machine in a manner that can reduce the stress that may occur in the cured resin material (resin material layer) within the magnet hole when it is mounted. [Brief explanation of the drawing]

[0008] [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 cross-sectional view of the rotor. [Figure 3] This is an enlarged view of the portion related to one of the magnetic poles shown in Figure 2. [Figure 4] This is a schematic cross-sectional view along line AA in Figure 3. [Figure 5] This is an enlarged view of section Q1 in Figure 4. [Figure 6] This is an explanatory diagram of a comparative example. [Figure 7] This is an explanatory diagram (part 1) of the structure of a rotor core formed by cross-stacking multiple stacked blocks. [Figure 8] This is an explanatory diagram (part 2) of the rotor core structure formed by cross-stacking multiple stacked blocks. [Figure 9] This flowchart schematically shows the manufacturing process of the motor 1 according to this embodiment. [Figure 10] This is an explanatory diagram of the workpiece support process. [Figure 11] This is an explanatory diagram of the magnet placement process. [Figure 12] This is an explanatory diagram of the nozzle positioning process. [Figure 13] This is an explanatory diagram of the resin placement process. [Figure 14]It is an explanatory diagram of a resin dispensing device for realizing a resin dispensing process. [Figure 15] It is an explanatory diagram of a resin dispensing device for realizing a resin dispensing process. [Figure 16] It is an explanatory diagram of an example of a resin injector. [Figure 17] It is an explanatory diagram of a resin curing process (pressing force applying process), and is a cross-sectional view schematically showing the state during the process. [Figure 18] It is a schematic flowchart related to an example of a method for setting a resin injector. [Figure 19] It is a schematic cross-sectional view explaining a press machine. [Figure 20] It is an explanatory diagram of the force required when peeling between steel plates. [Figure 21] It is an explanatory diagram of the injection pressure when the resin material leaks out between steel plates.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, each embodiment will be described in detail with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples and are not limited thereto, and the shapes and the like in the drawings may be partially exaggerated for the convenience of explanation.

[0010] FIG. 1 is a cross-sectional view schematically showing the cross-sectional structure of a motor 1 according to an embodiment. FIG. 2 is a cross-sectional view of a rotor 30 (a cross-sectional view by a plane perpendicular to the axial direction). In FIG. 2 and the like, for the sake of easy viewing, only some of the parts having the same attribute may be assigned reference numerals.

[0011] Figure 1 shows the rotation axis 12 of the motor 1. In the following explanation, "axial direction" refers to the direction in which the rotation axis (center of rotation) 12 of the motor 1 extends, "outer axial direction" refers to the side away from the axial center of the rotor core 32, and "inner axial direction" refers to the side toward the axial center of the rotor core 32. Furthermore, "radial direction" refers to the radial direction centered on the rotation axis 12, "outer radial direction" refers to the side away from the rotation axis 12, and "inner radial direction" refers to the side toward the rotation axis 12. Furthermore, "circumferential direction" corresponds to the direction of rotation around the rotation axis 12.

[0012] 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.

[0013] Motor 1 is an inner rotor type, and the stator 21 is provided so as to surround 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 includes a stator core 211 made of, for example, an annular laminated steel plate of magnetic material, and a plurality of slots (not shown) around which the coil 22 is wound are formed on the radially inner side of the stator core 211.

[0014] The rotor 30 is positioned radially inward of the stator 21.

[0015] The rotor 30 comprises a rotor core 32, a rotor shaft 34, end plates 35A and 35B, and permanent magnets 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 a shaft 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 similar methods. For example, the rotor core 32 may be coupled to the rotor shaft 34 by key coupling or spline coupling. The rotor shaft 34 is rotatably supported in the motor housing 10 via bearings 14a and 14b. The rotor shaft 34 defines the rotation axis 12 of the motor 1.

[0017] The rotor core 32 is formed, for example, from a laminated steel plate of an annular magnetic material. A permanent magnet 62 (see Figure 2) is embedded inside the rotor core 32. That is, the rotor core 32 has a magnet hole 322 (see Figure 2) that penetrates in the axial direction, and the permanent magnet 62 is inserted and fixed into the magnet hole 322. In a modified example, the rotor core 32 may be formed from a compacted body of magnetic powder that has been compressed and solidified.

[0018] 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 is configured such that each set of permanent magnets 62 overlaps every 45 degrees of rotation around the rotation axis 12.

[0019] Multiple permanent magnets 62 may be made of neodymium or the like. In this embodiment, as an example, as shown in Figure 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 pair of permanent magnets 62. The multiple permanent magnets 62 are arranged in such a manner that 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. In this embodiment, the permanent magnets 62 are identical in shape when viewed in the axial direction, but they may be different shapes. At least one of the permanent magnets 62 may be in an arc shape when viewed in the axial direction. In addition, another pair of permanent magnets may be arranged at a radial position different from that of the pair of permanent magnets 62. In this case, the fixing structure etc. related to the permanent magnets 62 described below can be similarly applied to other permanent magnets.

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

[0021] Next, with reference to Figure 3 and subsequent figures, the fixing structure of the permanent magnet 62 in the rotor core 32 will be described in detail. The following description will focus on the configuration for one magnetic pole, but the configuration for other magnetic poles may be similar.

[0022] Figure 3 is a schematic plan view showing the fixing structure of the permanent magnet 62 in the rotor core 32 according to this embodiment, and is an enlarged view of the portion related to one magnetic pole shown in Figure 2. The configuration related to one magnetic pole is basically symmetrical with respect to the d-axis (indicated as "d-axis" in Figure 3). The d-axis corresponds to the direction of the magnetic field generated by the permanent magnet 62 placed on the rotor 30. Figure 4 is a schematic cross-sectional view along line AA in Figure 3. Figure 5 is an enlarged view of portion Q1 in Figure 4, and is a schematic explanatory diagram of the anchor effect.

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

[0024] In this embodiment, as shown in Figures 3 and 4, the permanent magnet 62 is fixed by a resin material layer 72 within the magnet hole 322 of the rotor core 32.

[0025] The resin material layer 72 may be formed from, for example, a thermosetting resin or a thermoplastic resin. The 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 an anchoring effect, as schematically shown in Figure 5. In this case, the anchoring effect on the permanent magnet 62 side may be achieved by roughening the surface of the insulating layer 624 provided as a surface coating of the permanent magnet 62. The anchoring effect on the rotor core 32 side may be achieved by forming the rotor core 32 from laminated steel plates. Furthermore, the anchoring effect on the rotor core 32 side is enhanced by the resin placement process under "no pressure" described later.

[0026] As shown in Figure 4, the resin material layer 72 is bonded to the permanent magnet 62 in such a manner that both axial end faces 621 and 622 of the permanent magnet 62 are exposed. In other words, the resin material layer 72 is bonded only to the side surfaces of the permanent magnet 62 that intersect the axial direction.

[0027] In the example shown in Figure 4, the resin material layer 72 is joined to the outer periphery bridge 42 side (the outer periphery bridge 42 on the outer periphery surface 328 side of the rotor core 32) of the two sides in the circumferential direction of the permanent magnet 62. However, instead of this, or in addition, a resin material layer may be provided that is joined to the central bridge 44 side. In this case as well, the resin material layer joined to the central bridge 44 side of the permanent magnet 62 is joined to the circumferential wall surface of the magnet hole 322, thereby fixing the permanent magnet 62 to the rotor core 32.

[0028] Here, the effects of this embodiment will be explained by referring in contrast to the comparative example shown in Figure 6.

[0029] In the comparative example shown in Figure 6, the resin material layer 72' is provided so as to cover the Z1-side end face 621 of the axial end faces 621 and 622 of the permanent magnet 62. In this case, the bonding area between the resin material layer 72' and the permanent magnet 62 is increased, which can improve the bonding strength between the resin material layer 72' and the permanent magnet 62. However, as described above in the "Problems to be Solved by the Invention" section, a problem of thermal stress arises. That is, due to the difference in the coefficient of linear expansion between the permanent magnet 62 and the resin material layer 72', thermal stress caused by the difference in axial expansion and contraction that occurs between them during temperature changes becomes a problem. In the comparative example, the resin material layer 72' exposes the Z2-side end face 622 of the axial end faces 621 and 622 of the permanent magnet 62, so although the thermal stress caused by the difference in expansion and contraction is reduced, thermal stress caused by the local difference in expansion and contraction remains a problem on the Z1 side.

[0030] In contrast, according to this embodiment, as described above, the resin material layer 72 is joined to the permanent magnet 62 in such a manner that both axial end faces 621 and 622 of the permanent magnet 62 are exposed. As a result, the permanent magnet 62 and the resin material layer 72 can be displaced on both axial sides of the permanent magnet 62 without being substantially constrained by each other in the axial direction. Therefore, according to this embodiment, the disadvantages that occur in the comparative example (the problem of thermal stress caused by the difference in axial expansion and contraction between the permanent magnet 62 and the resin material layer 72) can be reduced.

[0031] In this embodiment, the resin material layer 72 preferably has one end face 7261 of the axial end faces 7261 and 7262 positioned axially inward relative to the axial end face 326 of the rotor core 32 than the other end face 7262. In the example shown in Figure 4, the end face 7261 on the Z1 side is positioned axially inward relative to the axial end face 326 of the rotor core 32 than the end face 7262 on the Z2 side. In this embodiment, the end face 7262 on the Z2 side is substantially flush with the axial end face 326, while the end face 7261 on the Z1 side is positioned significantly axially inward relative to the axial end face 326. In this case, the space SP1 on the Z1 side of the end face 7262 is more likely to face the permanent magnet 62 radially. This improves the workability when removing the permanent magnet 62 during disassembly, etc. That is, it becomes easier to remove the permanent magnet 62 by inserting a tool or the like into the space SP1, and the space SP1 can be effectively used as a work area when removing the permanent magnet 62. This will make it possible to contribute to achieving each of the Sustainable Development Goals (SDGs). In the following, of the axial end faces 7261 and 7262 of the resin material layer 72, the end face 7261 adjacent to the space SP1 in the axial direction will also be referred to as the "space-forming end face 7261".

[0032] Such an axially asymmetric resin material layer 72 configuration can be effectively utilized when forming the rotor core 32 by rolling multiple laminated blocks. Figures 7 and 8 are explanatory diagrams of a configuration that can be formed by rolling multiple laminated blocks of the rotor core 32.

[0033] For example, in the example shown in Figure 7, the rotor core 32A is formed by four laminated blocks 325(1) to 325(4). Each of the laminated blocks 325(1) to 325(4) is provided with a permanent magnet 62 and a resin material layer 72 in a form that is separate from each other. In the example shown in Figure 7, the two upper laminated blocks 325(1) and 325(2) and the two lower laminated blocks 325(3) and 325(4) are symmetrical (symmetrical with respect to the interface between laminated blocks 325(2) and 325(3)). On the other hand, the two upper laminated blocks 325(1) and 325(2) and the two lower laminated blocks 325(3) and 325(4) are asymmetrical with respect to each other. For example, of the two upper stacked blocks 325(1) and 325(2), the upper stacked block 325(1) has its end face 7261 on the space-forming side facing Z2, while the lower stacked block 325(2) has its end face 7261 on the space-forming side facing Z1.

[0034] In this case, the rotor core 32A, formed by cross-accumulating multiple stacked blocks 325(1) to 325(4), can have an overall axially symmetrical configuration while combining stacked blocks 325(1) to 325(4) that are asymmetrical in the axial direction. That is, the rotor core 32A can achieve a symmetrical configuration with respect to a plane that passes through the axial center of the rotor core 32A and is perpendicular to the axial direction.

[0035] Furthermore, in the example shown in Figure 8, the rotor core 32B is similarly formed from four stacked blocks 325(1) to 325(4), but the two upper stacked blocks 325(1) and 325(2) are different from the rotor core 32A shown in Figure 7. In this case, of the two upper stacked blocks 325(1) and 325(2), the upper stacked block 325(1) has its end face 7261 on the space-forming side facing Z1, and the lower stacked block 325(2) has its end face 7261 on the space-forming side facing Z2. In this case, the rotor core 32B formed by cross-accumulating multiple stacked blocks 325(1) to 325(4) can have an asymmetrical configuration in the axial direction as a whole. Such asymmetry may be used to adjust the weight balance with other components.

[0036] Next, the manufacturing method of the motor 1 according to this embodiment will be described with reference to Figure 9 and subsequent figures.

[0037] In the following explanation, as described above, the axial direction refers to the direction in which the central axis I0 of the rotor core 32 (workpiece W), which corresponds to the rotation axis 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 outward direction refers to the side away from the central axis I0 of the rotor core 32, and the radially inward direction I0 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.

[0038] Figure 9 is a flowchart schematically showing the flow of the manufacturing method of the motor 1 according to this embodiment. Figures 10 to 17 are explanatory diagrams of specific steps in the manufacturing method shown in Figure 9. Specifically, Figure 10 is an explanatory diagram of the workpiece support step, Figure 11 is an explanatory diagram of the magnet placement step, and Figure 12 is an explanatory diagram of the nozzle positioning step, each of which is a schematic cross-sectional view showing the state after the respective step. Figure 13 is an explanatory diagram of the resin placement step, and is a schematic cross-sectional view showing each state ST61, ST62, ST63, and ST64 in the resin placement step with respect to one magnet hole 322. Figures 14 and 15 are explanatory diagrams of the resin placement apparatus 130 for realizing the resin placement step, Figure 14 is a schematic cross-sectional view showing the state before the start of the resin placement step (the state after the completion of the nozzle positioning step), and Figure 15 is a schematic cross-sectional view showing the state during the resin placement step. Figure 16 is an explanatory diagram of an example of a resin injection machine 134. Figure 17 is an explanatory diagram of the resin curing process (pressure application process), and is a schematic cross-sectional view showing the state during the process.

[0039] This manufacturing method first includes a steel plate lamination step (step S1) in which multiple steel plates 3250 are laminated as a preparatory step for preparing the workpiece W of the rotor core 32. As described above with reference to Figures 7 and 8, the workpiece W of the rotor core 32 may be in units of laminated blocks 325.

[0040] Next, as schematically shown in Figure 10, this manufacturing method includes a workpiece support step (step S2) in which a workpiece W is placed on a support jig 120. The support jig 120 is an element of the manufacturing apparatus 100 and may support the workpiece W while also being responsible for transporting the workpiece W between each step. In this case, the support jig 120 may be in the form of a movable conveyor or the like, or it may be in the form of a transport tray that is transported by being placed on a conveyor or the like. Furthermore, the support jig 120 may be configured to be gripped by a transport robot.

[0041] Next, as schematically shown in Figure 11, this manufacturing method includes a magnet placement step (step S3) 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 placed such that their lower end faces 622 are in contact with the surface of the support jig 120 without any gaps (i.e., in surface contact).

[0042] Next, as schematically shown in Figure 12, this manufacturing method includes a nozzle positioning step (step S5) in which the nozzle 131 of the resin placement device 130 is positioned within the magnetic hole 322 of the workpiece W on the support jig 120. The nozzle 131 of the resin placement device 130 is positioned so as to be insertable into the remaining space within the magnetic hole 322 into which the permanent magnet 62 is inserted. For example, in the example shown in Figure 13, the nozzle 131 is positioned so as to be insertable into the space related to the flux barrier on one circumferential side (outer peripheral bridge 42 side) of the permanent magnet 62. Hereinafter, the remaining space within the magnetic hole 322 into which the permanent magnet 62 is inserted will also be referred to as the "nozzle insertion space".

[0043] Next, this manufacturing method includes a resin placement step (step S6) in which the resin material for forming the resin material layer 72 described above is placed in the magnet hole 322. In this case, the resin material does not need to fill the entire nozzle insertion space, and as shown in Figure 3, it may be placed in such a manner that a portion of the flux barrier remains as a space (a space where the resin material layer 72 does not exist).

[0044] In this embodiment, the resin material has a relatively high viscosity but is placed in a pre-cured state (a flowable state). Therefore, the resin material placed in the magnet hole 322 flows downward due to its own weight and reaches the surface of the support jig 120. However, if the resin material has a relatively high viscosity and is placed in such a manner that the lower end face 622 of the permanent magnet 62 is in contact with the surface of the support jig 120 without any gaps, the resin material will not substantially penetrate between the lower end face 622 of the permanent magnet 62 and the surface of the support jig 120. Therefore, as described above, the resin material layer 72 can be formed in such a manner that the lower end face 622 of the permanent magnet 62 is exposed.

[0045] In this manufacturing method, the resin placement step (step S6) includes positioning the nozzle 131, which is an element of the manufacturing apparatus 100, so that its discharge port 1310 is axially inward from the axial end face 326 of the rotor core 32 (the axial end face 326 on the insertion side, the same applies hereinafter) (see state ST61 in Figure 13), and discharging resin material from the discharge port 1310. The resin placement step (step S6) may also include discharging resin material from the discharge port 1310 while changing the axial position of the discharge port 1310 within the range in which the discharge port 1310 of the nozzle 131 is positioned axially inward (towards Z2) from the axial end face 326 of the rotor core 32. This makes it possible to form the resin material layer 72 in a manner that exposes the upper end face 621 as described above.

[0046] In the resin placement process (step S6) shown in Figure 13, the discharge port 1310 of the nozzle 131 is inserted to near the bottom of the nozzle insertion space (see state ST61), and then the discharge of the resin material 90 begins. In this case, the resin material 90 is discharged from the nozzle 131 while gradually raising the nozzle 131 (see state ST62) within the range where the discharge port 1310 is located axially inward (towards Z2) from the axial end face 326 of the rotor core 32. When the discharge port 1310 of the nozzle 131 reaches a discharge stop position axially inward from the axial end face 326 of the rotor core 32 (see state ST63), the discharge of the resin material 90 from the nozzle 131 stops, and the resin placement process (step S6) is completed (see state ST64).

[0047] The resin dispensing apparatus 130 usable in this manufacturing method is arbitrary as long as it has the nozzle 131 described above, but may have a configuration such as those shown in Figures 14 to 16.

[0048] In the example shown in Figures 14 to 16, the resin placement device 130, which is an element of the manufacturing apparatus 100, includes a resin injection machine 134, a table section 135, and a mold section 136.

[0049] As shown in Figure 16, the resin injection machine 134 is equipped with a resin material inlet 1340B for introducing solid resin, and a plunger 1345 for injecting molten resin material, which is fed through a screw 1346, from an injection port 1340A. The table section 135 may be fixed to the equipment. The mold section 136 is installed (supported) on the table section 135. The mold section 136 is equipped with a path for resin material for injection molding, such as a sprue, runner, and gate. The resin material path has branches to communicate with each nozzle 131, which is provided corresponding to each magnetic hole 322. The mold section 136 simultaneously places the resin material from the resin injection machine 134 into each magnetic hole 322 via each nozzle 131. Specifically, in the mold section 136, resin is injected from the injection port 1340A to the input port 1360A of the mold section 136, and then resin material is injected from each discharge port 1310 of the mold section 136, so that the resin material is simultaneously placed in multiple magnetic holes 322. In this embodiment, the resin injection machine 134 and the mold section 136 are separate components, but they may be integrated.

[0050] In this embodiment, the resin placement device 130 further includes a lifting mechanism 138 for raising and lowering the support jig 120. As shown in Figures 14 and 15, the lifting mechanism 138 can change the vertical position of the workpiece W relative to the mold section 136. This allows the position of the discharge port 1310 of the nozzle 131 relative to the workpiece W to be changed in the manner described above with reference to Figure 13. In a modified example, the table section 135 may be made vertically movable.

[0051] Although further details of the resin placement device 130 will not be described here, the configuration of the resin injection machine 134, the table section 135, and the mold section (runner section) 136 may be substantially the same as the elements described in International Patent Publication No. 2022 / 091389, whose disclosure is incorporated into this specification by reference herein. In addition, in the example shown in Figures 14 to 16, the resin material is placed in the multiple magnetic holes 322 simultaneously, but the resin material may also be placed in the multiple magnetic holes 322 in portions while the workpiece W is rotated.

[0052] In this manufacturing method, the resin placement step (step S6) is performed without substantially pressing the rotor core 32 in the axial direction (i.e., without applying a pressing force to the rotor core 32). Therefore, a pressing mechanism that grips and presses the workpiece W from above and below is substantially unnecessary, and the equipment can be simplified.

[0053] In general injection molding (injection molding) of resin material using an injection molding machine (the same applies to the resin injection machine 134), there is a tendency to maintain a relatively high injection pressure in order to continuously apply a pressure at least greater than atmospheric pressure to the filled resin material, from the viewpoint of preventing voids, etc. Increasing the injection pressure increases the possibility of resin material leaking from between the steel plates 3250 that form the rotor core 32. Such leakage of resin material may lead to a deterioration in the characteristics of the rotor 30 into which the rotor core 32 is incorporated.

[0054] In this respect, in this embodiment, because the bonding strength of the resin material layer 72 due to the anchoring effect described above is high, the necessary fixing strength can be easily secured even if voids occur in the resin material layer 72. For this reason, according to this embodiment, there is no need to apply a pressure at least greater than atmospheric pressure to the filled resin material, and the need to use a relatively high injection pressure can be reduced. As a result, in this manufacturing method, even without applying a pressing force to the rotor core 32 during the resin placement process, the possibility of resin material leaking from between the steel plates 3250 can be reduced.

[0055] In this embodiment in particular, the resin material is placed in the magnet hole 322 of the workpiece W in an uncured state while the inside of the magnet hole 322 is exposed to atmospheric pressure. As a result, the pressure of the resin material injected into the magnet hole 322 decreases immediately, and the possibility of the resin material leaking out from between the steel plates 3250 can be greatly reduced. Note that the state in which the inside of the magnet hole 322 of the workpiece W is exposed to atmospheric pressure does not simply mean that it is in communication with the atmosphere through a vent hole, but also includes, for example, a state in which the top of the magnet hole 322 is exposed to the atmosphere.

[0056] Furthermore, in this manufacturing method, the resin material is placed under no pressure, without applying any pressing force to the rotor core 32. This allows the resin material to be bonded to the rotor core 32 with a larger gap between the steel plates 3250 of the rotor core 32 compared to when the resin material is placed under pressure. This enhances the anchoring effect described above (i.e., the anchoring effect is enhanced by the resin placement process under "no pressure"). In addition, the pressing mechanism that clamps and presses the workpiece W from above and below can be omitted or simplified. In other words, resources such as jigs and energy used for pressing can be reduced compared to when the resin material is placed under pressure.

[0057] Next, this manufacturing method includes a resin curing step (step S7) in which a pressing force is applied to the rotor core 32 while the resin material placed in the magnet hole 322 is cured. The resin curing step (step S7) may be performed after the workpiece W has been removed from the resin placement device 130. The resin curing step (step S7) includes heating the workpiece W while applying a pressing force to the rotor core 32 of the workpiece W to heat-cure the resin material. In this embodiment, the state of applying a pressing force to the rotor core 32 may be maintained until the resin material (resin material layer 72), which has been heated to a high temperature in the resin curing step, has cooled to ambient temperature, or it may be released before it has cooled to ambient temperature.

[0058] In the example shown in Figure 17, the heating device 160, which is an element of the manufacturing apparatus 100, is positioned radially inside and radially outside the rotor core 32 of the workpiece W, and can heat-cur the resin material 90 via the rotor core 32. The manufacturing apparatus 100 also has a pressing jig 170 that applies a pressing force to the rotor core 32, as shown in Figure 17. The pressing jig 170 can apply a pressing force to the rotor core 32 by pressing down on the workpiece W on the support jig 120 from above (see pressing force F90) (see pressing force F92). In a modified example, pressing may be achieved using a lower jig different from the support jig 120. For example, the resin curing process (step S7) may be realized using a mold jig that incorporates the heating device 160 and is capable of clamping in the vertical direction. The heating device may also be realized by a heating furnace.

[0059] In this manufacturing method, the magnitude of the pressing force F92 is preferably set based on the magnitude of the pressing force that the rotor core 32 receives when assembling the rotor 30 using the rotor core 32 in the subsequent step S8. The pressing force that the rotor core 32 receives when assembling the rotor 30 may correspond to, for example, the pressing force generated by being clamped by the end plate 35A (see force F10 in Figure 1). In this case, the magnitude of the pressing force F92 may correspond to the design value or measured value of the pressing force F10. Note that the design value does not necessarily have to be the value stated in the design drawing, but is a concept that includes suitable values ​​and target values ​​obtained through design analysis, etc. The measured value may be the measured value of the motor 1 before and / or after mass production.

[0060] In this manufacturing method, the magnitude of the pressing force F92 applied to the workpiece W is set based on the magnitude of the pressing force F10 (hereinafter also simply referred to as "pressing force F10 in the mounted state") that the rotor core 32 receives when assembling the rotor 30.

[0061] Incidentally, unlike this manufacturing method, it is also possible to configure the resin curing process in which no pressing force is applied to the rotor core 32 of the workpiece W (i.e., the magnitude of the pressing force F92 is set to 0). Alternatively, unlike this manufacturing method, it is also possible to configure the resin curing process in which a pressing force significantly larger than the pressing force F10 in the mounted state is applied.

[0062] However, in these configurations, significant stress is likely to occur in the resin material layer 72 due to a significant difference between the pressing force applied to the rotor core 32 during the resin curing process and the pressing force F10 in the mounted state. Specifically, if there is a significant difference between the pressing force applied to the rotor core 32 during the resin curing process and the pressing force F10 in the mounted state, the axial length of the rotor core 32 changes before and after mounting. This change in axial length makes it likely for significant stress to occur in the resin material layer 72 bonded to the rotor core 32. This problem occurs in both configurations where no pressing force is applied to the rotor core 32 of the workpiece W during the resin curing process, and configurations where a pressing force significantly greater than the pressing force F10 in the mounted state is applied during the resin curing process.

[0063] In contrast, according to this embodiment, the resin curing process is performed in such a way that the difference between the pressing force applied to the rotor core 32 during the resin curing process and the pressing force F10 in the mounted state is minimized. As a result, in the mounted state in which the rotor core 32 is incorporated into the motor 1, the stress that may occur in the resin material layer 72 due to the pressing force F10 in the mounted state can be reduced or eliminated. In other words, in this embodiment, the pressing force applied to the rotor core 32 during the resin curing process is adjusted to reduce or eliminate the stress that may occur in the resin material layer 72 due to the pressing force F10 in the mounted state.

[0064] Furthermore, in this manufacturing method, in the resin curing process, pressing force is applied to the rotor core 32 as described above, while in the resin placement process (step S6) described above, pressing force is not applied to the rotor core 32 as described above. Therefore, the resin curing process can be performed with the workpiece W removed from the resin placement device 130 used in the resin placement process (step S6) described above. In other words, the pressing jig 170 can be positioned separately from the resin placement device 130. This reduces the time the resin placement device 130 is constrained for one workpiece W, and allows the resin placement process (step S6) to be performed efficiently for multiple workpieces W.

[0065] Next, this manufacturing method includes a fixing step (step S8) in which the rotor core 32, which has completed step S7, is assembled with the rotor 30. For example, the rotor core 32 is fixed to the rotor shaft 34 (e.g., by press-fitting), and the end plates 35A and 35B are attached. This applies a pressing force F10 (see Figure 1) to the rotor core 32 in the mounted state. The rotor 30 assembled in this way is then assembled into a case (not shown) together with the stator 21, etc., and the motor 1 is assembled.

[0066] Next, with reference to Figures 18 to 21, a preferred method for setting the injection pressure of the resin injector 134 in the resin placement process (step S6) described above will be explained. In this embodiment, the resin injector 134 can also be used in a form that is not incorporated into the injection molding machine (resin placement device 130). That is, a resin injector equipped with a plunger and having a nozzle corresponding to the nozzle 131 in the discharge portion may be used instead of the resin placement device 130. In this case, in the following and above descriptions, the term "injection" can be read as the term "injection". Accordingly, the term "injection pressure" can be read as the term "injection pressure".

[0067] Figure 18 is a schematic flowchart illustrating an example of how to set up the resin injection machine 134. Figure 19 is a schematic cross-sectional view illustrating the press machine 142.

[0068] In step S61, the method for setting up the resin injection machine 134 includes obtaining values ​​for manufacturing parameters related to the steel sheet lamination process (step S1) described above, with reference to Figure 9.

[0069] In the examples shown in Figures 18 and 19, the manufacturing parameters include the design value or measured value of the pressing force applied by the press machine 142 when joining the steel plates 3250 of the rotor core 32.

[0070] Here, an example of the press machine 142, which is the basis for this explanation, will be described with reference to Figure 19.

[0071] In the example shown in Figure 19, the press machine 142 works in cooperation with the squeeze ring 144 and the support device 146 to simultaneously perform press working and lamination. Specifically, the press machine 142 may be part of a progressive die and may be a press working device that punches out the outer shape (outer contour) of the steel sheet 3250. The press machine 142 includes, for example, a punch 1421 that is movable in the vertical direction and a die 1422. When the punch 1421 enters the die 1422, the material (e.g., a rolled sheet that has undergone various prior processes) is punched into the steel sheet 3250. The press machine 142 itself may be implemented by a corresponding part of a press working device described in WO2019 / 066032, whose disclosure is incorporated into this specification by reference herein.

[0072] The press machine 142 may utilize the axial force during press working (for example, force from a hydraulic cylinder) to apply pressure to the steel plate 3250 for joining (crimping) using dowels (not shown). That is, the press machine 142 may perform press working (press forming) to punch out a new steel plate 3250, and at the same time apply pressure to the uppermost steel plate 3250 of the workpiece W below it to join them.

[0073] The squeeze ring 144 is cylindrical in shape and is positioned below the die 1422. The squeeze ring 144 may be fixed to the die 1422 in a manner that integrates it with the die 1422.

[0074] The support device 146 is, for example, in the form of a back pressure pad and works in cooperation with the punch 1421 to realize the pressurization required for dowel joining during the press working process described above. That is, as shown in Figure 19, the punch 1421 generates a reaction force F2 to the downward pressing force F1 applied by the punch to the workpiece W, thereby realizing the joining of the steel plates 3250 by pressurization described above.

[0075] In the example shown in Figure 19, the design value or measured value of the pressing force by the press machine 142 may correspond to the design value or measured value of force F1. Alternatively, the design value or measured value of the pressing force by the press machine 142 may correspond to the design value or measured value of the reaction force F2 correlated with force F1. Furthermore, in the configuration in which each stacked block 325 is rolled as described above, the design value or measured value of the pressing force by the press machine 142 may include the same value when joining the stacked blocks 325 together.

[0076] Next, in step S62, the method for setting the resin injection machine 134 includes adjusting the injection pressure of the resin injection machine 134 as appropriate, based on the manufacturing parameter values ​​obtained in step S61, so that resin material does not leak out from between the steel plates 3250 during the resin placement process (step S6) described above. In this case, the injection pressure of the resin injection machine 134 may be adjusted to a target pressure corresponding to the manufacturing parameter values ​​obtained in step S61. In this case, the target pressure may correspond to the pressure generated between the steel plates 3250 due to the pressing force by the press machine 142 (see force F1 in Figure 19), as described above.

[0077] Furthermore, the setting method for the resin injection machine 134 shown in Figure 18 does not need to be performed for each workpiece W, and may be performed periodically or irregularly. Also, the setting method for the resin injection machine 134 may be adapted during the development and design stage, or it may only be performed at the start of mass production. In this way, the injection pressure of the resin injection machine 134 can be adjusted as needed and at the appropriate timing, and can, for example, respond to changes over time.

[0078] In this way, as shown in the examples in Figures 18 and 19, the injection pressure of the resin injection machine 134 can be adjusted according to the pressing force applied by the press machine 142 when joining the steel plates 3250 of the rotor core 32, thereby reducing the possibility of resin material leaking from between the steel plates 3250.

[0079] In the examples shown in Figures 18 and 19, the manufacturing parameters include the design value or measured value of the pressing force applied by the press machine 142 when joining the steel plates 3250 of the rotor core 32, but the manufacturing parameters are not limited to these. For example, the manufacturing parameters may include the calculated or measured value of the force required to separate the steel plates 3250, and the calculated or measured value of the injection pressure when the resin material leaks out from between the steel plates 3250. Even with such manufacturing parameters, they can be used to adjust the injection pressure of the resin injection machine 134, similar to the pressing force applied by the press machine 142 described above, thereby reducing the possibility of the resin material leaking out from between the steel plates 3250.

[0080] Figure 20 is an explanatory diagram of the force required to separate the steel plates 3250. Figure 20 illustrates the axial outward force acting on both end faces of the workpiece W as the force required to separate the steel plates 3250. The measurement of the force F20 required to separate the steel plates 3250 may be performed periodically or irregularly on the workpiece W obtained in the steel plate lamination process (step S1), for example. Alternatively, the force F20 may be derived or measured during the development and design stage, or it may be measured only at the start of mass production. In this case, the injection pressure of the resin injection machine 134 can be adjusted accurately based on the measurement results.

[0081] In this case, the injection pressure of the resin injection machine 134 may be adjusted to be significantly lower than the pressure required for the force F20 needed to separate the steel plates 3250 (i.e., the pressure required for separation between the steel plates 3250). This reduces or eliminates the possibility of resin material leaking from between the steel plates 3250 during the resin placement process (step S6).

[0082] Figure 21 is an explanatory diagram of the injection pressure when the resin material 90 leaks out from between the steel plates 3250. In Figure 21, the state in which the resin material 90 leaks out from between the steel plates 3250 is schematically shown in an enlarged view of section Q2 in Figure 20, along with the force (see force F21) acting between the steel plates 3250 due to the resin material.

[0083] As described above, if the injection pressure of the resin injector 134 in the resin placement process (step S6) is set to a relatively high value, the possibility of resin material leaking from between the steel plates 3250 forming the rotor core 32 increases. Therefore, the injection pressure of the resin injector 134 may be adjusted to be significantly lower than the injection pressure at which resin material leaks from between the steel plates 3250. This reduces or eliminates the possibility of resin material leaking from between the steel plates 3250 during the resin placement process (step S6).

[0084] Incidentally, the preferred method for setting the injection pressure of the resin injection machine 134 described above, with reference to Figures 18 to 21, is applicable not only to the resin placement process (step S6) described above, but also to the filling (injection) of other resin materials into the axial holes of the laminated iron core for the rotor core. For example, in the embodiment described above, the permanent magnet 62 is a sintered magnet, but it can also be formed from a bonded magnet. In this case, the preferred method for setting the injection pressure of the resin injection machine 134 described above is also applicable to a configuration in which a material for bonded magnets (a material mixed with magnet powder and a binder) is filled into the magnet holes 322.

[0085] 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.

[0086] For example, in the embodiment described above, the upper surface of the support jig 120 (the surface that contacts the axial end face 326 of the rotor core 32) is a flat plane, but is not limited to this. The upper surface of the support jig 120 may be formed in a convex shape only in the flat portion that contacts the end face 622 of the permanent magnet 62, with the convex shape extending upward (towards Z1) compared to the other flat portions. In this case as well, the surface contact between the upper surface of the support jig 120 and the end face 622 of the permanent magnet 62 prevents the formation of the resin material layer 72 on the end face 622 of the permanent magnet 62.

[0087] Furthermore, in the embodiments described above, the injection molding or resin injection method is optional and may include, for example, transfer molding or resin injection by compression molding using a cylinder. [Explanation of Symbols]

[0088] 1...Motor (rotating electric machine), 30...Rotor (rotor for rotating electric machine), 32, 32A...Rotor core (laminated iron core), 322...Magnet hole, 34...Rotor shaft, 35A, 35B...End plate, 62...Permanent magnet, 90...Resin material, 100...Manufacturing equipment, 120...Support jig (support part), 130...Resin placement device, 160...Heating device, 170...Pressing jig, W...Workpiece

Claims

1. A rotor core having magnetic holes, wherein permanent magnets are arranged in the magnetic holes; A resin placement step in which a resin material is placed in the magnet hole of the rotor core in an uncured state without applying an axial pressing force to the rotor core, A method for manufacturing a rotor for a rotating electric machine, comprising the resin curing step of curing the resin material while pressing the rotor core in the axial direction after the resin placement step.

2. The method for manufacturing a rotor for a rotating electric machine according to claim 1, wherein the magnitude of the pressing force applied to the rotor core is set based on a design value or measured value of the magnitude of the pressing force received by the rotor core when it is incorporated into the rotating electric machine.

3. The method for manufacturing a rotor for a rotating electric machine according to claim 1, wherein the resin arrangement step is performed with one end face on the axial side of the rotor core open.

4. A rotor core having magnetic holes, wherein permanent magnets are arranged in the magnetic holes; A resin placement step in which a resin material is placed in the magnet hole of the rotor core in an uncured state without applying an axial pressing force to the rotor core, Following the resin placement step, a resin curing step is performed in which the rotor core is pressed in the axial direction while the resin material is cured. The process includes, after the resin material has hardened in the resin hardening step, fixing the rotor core to the rotor shaft by pressing it in the axial direction, A method for manufacturing a rotating electric machine, wherein the magnitude of the pressing force applied to the rotor core in the resin curing step is adapted based on a design value or measured value of the magnitude of the pressing force applied to the rotor core in the fixed state achieved by the fixing step.

5. The method for manufacturing a rotating electric machine according to claim 4, wherein the fixing step includes pressing the rotor core in the axial direction by attaching end plates in a manner that presses both end faces of the rotor core in the axial direction.

6. A rotor core having magnetic holes, comprising a support portion that supports the rotor core in which permanent magnets are arranged within the magnetic holes, A resin placement device for placing resin material in an uncured state within the magnet hole of the rotor core supported by the support portion, without applying axial pressure to the rotor core, A pressing jig is provided separately from the support portion and presses the rotor core in the axial direction, A manufacturing apparatus for a rotor for a rotating electric machine, comprising a heating device for curing the resin material, which has been placed by the resin placement device, while pressing the rotor core axially with the pressing jig.

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