Rotor core and method for manufacturing a rotor core

Abstract

The present invention relates to a rotor core and a manufacturing method of a rotor core. In the rotor core, a permanent magnet includes a compression bonded magnet including a magnetic material and a compression molding resin material, and is provided in a magnet hole portion, and an injection bonded magnet including a magnetic material and an injection molding resin material, and is provided to be adjacent to the compression bonded magnet in the magnet hole portion.

Description

Technical Field

[0001] This invention relates to rotor cores and methods for manufacturing rotor cores. Background Technology

[0002] Previously, rotor cores using bonded magnets as permanent magnets disposed in the holes of magnets were known. For example, such rotor cores were disclosed in Japanese Patent Application Publication No. 2016-96665.

[0003] Japanese Patent Application Publication No. 2016-96665 discloses a rotor core in which magnet mounting holes (magnet hole portions) are formed, and permanent magnets are embedded and fixed in the magnet mounting holes. In the rotor core described in Japanese Patent Application Publication No. 2016-96665, the permanent magnets include a first magnet (bonded magnet) and a second magnet (bonded magnet). The first magnet is formed by injection molding a first magnet material into the magnet mounting hole. The second magnet is formed by injection molding a second magnet material into the gap where the first magnet is not disposed within the magnet mounting hole. That is, the second magnet is positioned adjacent to the first magnet within the magnet mounting hole. The first and second magnet materials are composed of a mixture of magnetite powder and resin. Furthermore, the proportion of magnetite powder in the second magnet material is smaller than that in the first magnet material (the proportion of resin is larger than that in the first magnet material). Therefore, the adhesion of the second magnet is lower than that of the first magnet. Furthermore, in the rotor core described in Japanese Patent Application Publication No. 2016-96665, after the first magnet is formed by injection molding into the magnet mounting hole, the second magnet is formed by injection molding into the magnet mounting hole.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2016-96665

[0005] However, in the rotor core described in Japanese Patent Application Publication No. 2016-96665, both the first and second magnets constituting the permanent magnets are injection-molded bonded magnets. While this provides good machinability and a high degree of freedom in the shape of the permanent magnets, a relatively high proportion of resin is required in the bonded magnets to ensure the fluidity of the material during injection molding. In this case, the proportion of magnet powder in the bonded magnets is relatively low, resulting in a lower magnetic flux density of the permanent magnets. That is, motor performance is reduced. Furthermore, in the rotor core described in Japanese Patent Application Publication No. 2016-96665, the bonded magnets constituting the permanent magnets are formed by injection molding, first forming the bonded magnets within the magnet mounting holes (magnet hole portions). Therefore, the shape and weight of the first magnet sometimes differ in each magnet mounting hole. This also leads to a reduction in motor performance. Therefore, as in the rotor core described in Japanese Patent Application Publication No. 2016-96665, when the permanent magnets are constituted by bonded magnets, a rotor core that can improve motor performance is desired. Therefore, in order to solve the aforementioned problems, it has been considered to use adhesive magnets formed first in the magnet mounting holes (magnet holes) or sintered magnets, for example, formed by sintering pressed powder to a solid state (sintering) at high temperature. However, after sintering, sintered magnets require heat treatment to optimize the crystal structure and surface finishing to grind rough surfaces, which leads to problems such as complex manufacturing processes. Summary of the Invention

[0006] The present invention was made to solve the aforementioned problems. One object of the present invention is to provide a rotor core and a method for manufacturing the rotor core that can prevent the complexity of the manufacturing process and improve motor performance when the permanent magnet is composed of adhesive magnets.

[0007] To achieve the above objectives, the rotor core of the first aspect of the present invention comprises: an annular stacked core, which is constructed by stacking a plurality of electromagnetic steel plates and has a magnet hole; and a permanent magnet disposed in the magnet hole, the permanent magnet comprising: a compression bond magnet, which comprises a magnetic material and a compression molding resin material for bonding the particles of the magnetic material together, and is disposed in the magnet hole; and an injection bond magnet, which comprises a magnetic material and an injection molding resin material for bonding the particles of the magnetic material together, and is disposed adjacent to the compression bond magnet in the magnet hole.

[0008] In the rotor core of the first aspect of the present invention, as described above, the permanent magnet includes: a compression-bonded magnet comprising magnetic material and compression-molding resin material, and disposed in a magnet hole; and an injection-bonded magnet comprising magnetic material and injection-molding resin material, and disposed adjacent to the compression-bonded magnet in the magnet hole. Thus, the compression-bonded magnet, unlike the injection-bonded magnet, does not require fluidity to increase the proportion of magnetic material, so compared to the case where a first injection-bonded magnet and a second injection-bonded magnet are disposed in the magnet hole, the proportion of magnetic material in the permanent magnet can be increased. Furthermore, in the case where both the compression-bonded magnet and the injection-bonded magnet are disposed in the magnet hole, considering the simplification of the manufacturing process, after the compression-bonded magnet is formed in the magnet hole by compression molding, there is no gap for the compression-bonded magnet in the magnet hole, and the injection-bonded magnet is formed adjacent to the compression-bonded magnet by injection molding. That is, in the adhesive magnet constituting the permanent magnet, the adhesive magnet (compression-bonded magnet) first formed in the magnet hole is formed by compression molding, so the differences in shape and weight of the compression-bonded magnets in each magnet hole can be reduced. Furthermore, unlike sintered magnets, compression-bonded magnets do not require heat treatment to optimize the crystalline structure or surface finishing to roughen the surface, thus simplifying the manufacturing process. As a result, when permanent magnets are constructed from bonded magnets, manufacturing complexity can be prevented, and motor performance can be improved.

[0009] Furthermore, in order to achieve the above-mentioned objective, the rotor core manufacturing method of the second aspect of the present invention comprises a rotor core having an annular stacked core composed of multiple stacked electromagnetic steel plates and having magnet holes formed therein, and a method for manufacturing a rotor core having permanent magnets disposed in the magnet holes. The method includes the following steps: a compression molding step, in which a compression-bonded magnet is formed by compressing a material containing magnetic material and a compression molding resin material for bonding particles of the magnetic material together; a placement step, after the compression molding step, in which the compression-bonded magnet is disposed in the magnet holes of the rotor core; and an injection molding step, after the placement step, in which, in the absence of gaps in the magnet holes where the compression-bonded magnet is disposed, an injection molding process is performed by injecting a material containing magnetic material and an injection molding resin material for bonding particles of the magnetic material into the magnet holes, thereby forming an injection-bonded magnet.

[0010] In the manufacturing method of the rotor core of the second aspect of the present invention, as described above, in the compression molding process, the compression-bonded magnet is formed by compression molding, and in the injection molding process, the injection-bonded magnet is formed by injection molding in the gap where the compression-bonded magnet is not disposed in the magnet hole. Therefore, similar to the rotor core of the first aspect, the compression-bonded magnet does not require the same fluidity as the injection-bonded magnet, allowing for a higher proportion of magnetic material. Thus, compared to the case where the second injection-bonded magnet is injection-molded in the gap where the first injection-bonded magnet is not disposed in the magnet hole, the proportion of magnetic material in the permanent magnet can be increased. Furthermore, similar to the rotor core of the first aspect, in the bonded magnet constituting the permanent magnet, the bonded magnet (compression-bonded magnet) first formed in the magnet hole is formed by compression molding, thus reducing the differences in shape and weight of the compression-bonded magnets in each magnet hole. Additionally, similar to the rotor core of the first aspect, the compression-bonded magnet, unlike the sintered magnet, does not require heat treatment for optimizing the crystal structure or surface finishing for grinding rough surfaces, thus simplifying the manufacturing process. The above results indicate that, similar to the rotor core in the first aspect, when permanent magnets are formed by bonding magnets, it is possible to prevent the complexity of the manufacturing process and improve motor performance.

[0011] According to the present invention, as described above, a rotor core and a method for manufacturing the rotor core are provided that, when a permanent magnet is formed by adhesive magnets, can prevent the complexity of the manufacturing process and improve the performance of the motor. Attached Figure Description

[0012] Figure 1 This is a top view showing the structure of the rotor core of the first embodiment.

[0013] Figure 2 This is a cross-sectional view showing the state of the stacked iron core being pressed by a clamp in the first embodiment.

[0014] Figure 3A The first figure shows the simulation results of torque pulsation when the proportion of magnetic material in the compressed bonded magnet of the rotor core of the first embodiment changes.

[0015] Figure 3B The first figure shows the simulation results of the cogging torque when the proportion of magnetic material in the compressed bonded magnet of the rotor core of the first embodiment changes.

[0016] Figure 3C The second figure shows the simulation results of torque pulsation when the proportion of magnetic material in the compressed bonded magnet of the rotor core of the first embodiment changes.

[0017] Figure 3DThe second figure shows the simulation results of the cogging torque when the proportion of magnetic material in the compressed bonded magnet of the rotor core of the first embodiment is changed.

[0018] Figure 3E The third figure shows the simulation results of torque pulsation when the proportion of magnetic material in the compressed bonded magnet of the rotor core of the first embodiment changes.

[0019] Figure 3F The third figure shows the simulation results of the cogging torque when the proportion of magnetic material in the compressed bonded magnet of the rotor core of the first embodiment is changed.

[0020] Figure 4 This is a cross-sectional view showing the structure of the resin injection device according to the first embodiment.

[0021] Figure 5 This is a flowchart illustrating the manufacturing method of the rotor core according to the first embodiment.

[0022] Figure 6A This is the first figure illustrating the compression bonding magnet molding process of the rotor core manufacturing method of the first embodiment.

[0023] Figure 6B This is the second figure illustrating the compression bonding magnet molding process of the rotor core manufacturing method of the first embodiment.

[0024] Figure 6C This is the third figure illustrating the compression bonding magnet molding process of the rotor core manufacturing method of the first embodiment.

[0025] Figure 6D This is the fourth figure illustrating the compression bonding magnet molding process of the rotor core manufacturing method of the first embodiment.

[0026] Figure 7A This is the first diagram illustrating the compression-bonded magnet arrangement process in the method for manufacturing the rotor core of the first embodiment.

[0027] Figure 7B This is the second figure illustrating the compression-bonded magnet arrangement process in the method for manufacturing the rotor core of the first embodiment.

[0028] Figure 8A This is the first figure illustrating the injection bonding magnet molding process of the rotor core manufacturing method of the first embodiment.

[0029] Figure 8B This is the second figure illustrating the injection bonding magnet molding process of the rotor core manufacturing method of the first embodiment.

[0030] Figure 8CThis is the third figure illustrating the injection bonding magnet molding process of the rotor core manufacturing method of the first embodiment.

[0031] Figure 8D This is the fourth figure illustrating the injection bonding magnet molding process of the rotor core manufacturing method of the first embodiment.

[0032] Figure 9A This is the first figure illustrating the injection bonding magnet molding process of the rotor core manufacturing method of the first embodiment.

[0033] Figure 9B This is the second figure illustrating the injection bonding magnet molding process of the rotor core manufacturing method of the first embodiment.

[0034] Figure 9C This is the third figure illustrating the injection bonding magnet molding process of the rotor core manufacturing method of the first embodiment.

[0035] Figure 9D This is a diagram illustrating the permanent magnetization process of the rotor core manufacturing method of the first embodiment.

[0036] Figure 10 This is a top view showing the structure of the rotor core in the second embodiment.

[0037] Figure 11A The first figure shows the simulation results of torque pulsation when the proportion of magnetic material in the compressed bonded magnet of the rotor core of the second embodiment changes.

[0038] Figure 11B The first figure shows the simulation results of the cogging torque when the proportion of magnetic material in the compressed bonded magnet of the rotor core of the second embodiment is changed.

[0039] Figure 11C The second figure shows the simulation results of torque pulsation when the proportion of magnetic material in the compressed bonded magnet of the rotor core of the second embodiment changes.

[0040] Figure 11D The second figure shows the simulation results of the cogging torque when the proportion of magnetic material in the compressed bonded magnet of the rotor core of the second embodiment is changed.

[0041] Figure 11E The third figure shows the simulation results of torque pulsation when the proportion of magnetic material in the compressed bonded magnet of the rotor core of the second embodiment changes.

[0042] Figure 11FThe third figure shows the simulation results of the cogging torque when the proportion of magnetic material in the compressed bonded magnet of the rotor core of the second embodiment is changed. Detailed Implementation

[0043] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0044] [First Implementation Method]

[0045] Reference Figure 1 Figure 9 illustrates the structure and manufacturing method of the rotor core 10 of the first embodiment.

[0046] (Structure of a rotary electric machine)

[0047] First, refer to Figure 1 The structure of the rotary electric machine 1 equipped with the rotor core 10 will be described.

[0048] In the following description, the axial, radial, and circumferential directions of the rotor core 10 are respectively designated as the Z direction, R direction, and C direction. Furthermore, one side and the other side in the Z direction are designated as the Z1 side and the Z2 side, respectively. Additionally, one side (inner diameter side) and the other side (outer diameter side) in the R direction are designated as the R1 side and the R2 side, respectively.

[0049] like Figure 1 As shown, the rotary electric motor 1 includes a rotor 2 and a stator 3. The rotor 2 includes a rotor core 10. The rotary electric motor 1 is, for example, a motor, a generator, or a combination of both. The rotor 2 and the stator 3 are both formed in annular shape. Moreover, the rotor 2 is arranged opposite to the stator 3 on the R1 side. That is, the rotary electric motor 1 is configured as an internal rotor type rotary electric motor. In addition, a shaft 4 is arranged on the R1 side of the rotor 2. The shaft 4 is connected to the engine or axle via a rotational force transmission component such as gears.

[0050] The stator 3 includes a stator core 3a and a coil 3b disposed on the stator core 3a. The stator core 3a is, for example, composed of multiple electromagnetic steel plates (silicon steel plates) stacked along the Z direction, and configured to allow magnetic flux to pass through. The coil 3b is connected to an external power source and is configured to be supplied with electricity (e.g., three-phase AC power). Furthermore, the coil 3b is configured to generate a magnetic field by supplying electricity. Additionally, the rotor 2 and shaft 4 are configured to rotate relative to the stator 3 even when no electricity is supplied to the coil 3b, driven by an engine or the like. Furthermore, in Figure 1 Although a portion of coil 3b is shown in the figure, coil 3b is arranged around the entire circumference of stator core 3a.

[0051] (Structure of the rotor core)

[0052] Next, refer to Figure 1Figure 3 illustrates the structure of the rotor core 10.

[0053] like Figure 2 As shown, the rotor core 10 includes multiple electromagnetic steel plates 11a arranged along the rotation axis A of the rotor core 10 (refer to...). Figure 1 A stacked iron core 11 is formed by stacking iron cores in the Z-direction. The stacked iron core 11 has a magnet hole 11b extending along the stacking direction (Z-direction) of the electromagnet plate 11a. For example... Figure 1 As shown, a plurality of (32) magnet holes 11b are provided in the laminated iron core 11. The magnet holes 11b are arranged on the R2 side of the rotor iron core 10. In the rotor iron core 10, two adjacent magnet holes 11b are arranged in a V-shape. Furthermore, in Figure 2 The image shows the stacked iron core 11 in a state configured in the clamp 20 described later.

[0054] The rotor core 10 includes a permanent magnet 12. The permanent magnet 12 is housed (configured) in the magnet hole 11b of the laminated core 11. The permanent magnet 12 is fixed to the magnet hole 11b. That is, the rotary motor 1 is configured as an interior permanent magnet motor (IPM motor). The cross-section of the permanent magnet 12 orthogonal to the Z direction has a rectangular shape. For example, the permanent magnet 12 is configured such that the magnetization direction is the short side direction.

[0055] like Figure 2 As shown, in the first embodiment, the permanent magnet 12 includes a compression-bonded magnet 12a and an injection-bonded magnet 12b. The compression-bonded magnet 12a includes a magnetic material and a compression-molding resin material for bonding the particles of the magnetic material together. The compression-bonded magnet 12a is formed by compression molding a material (hereinafter, compression-molding material) 61a (see FIG. 6) containing the magnetic material and the compression-molding resin material. The injection-bonded magnet 12b includes a magnetic material and an injection-molding resin material for bonding the particles of the magnetic material together. The injection-bonded magnet 12b is formed by compression molding a material (hereinafter, injection-molding material) 61b (see FIG. 6) containing the magnetic material and the injection-molding resin material. Figure 4It is formed by injection molding. The injection-bonded magnet 12b is provided in the gap in the magnet hole 11b where the compression-bonded magnet 12a is not disposed. That is, the injection-bonded magnet 12b is provided in the magnet hole 11b, adjacent to the compression-bonded magnet 12a. As a result, the compression-bonded magnet 12a does not require the same fluidity as the injection-bonded magnet 12b to increase the proportion of magnetic material. Therefore, compared with the case where the first injection-bonded magnet and the second injection-bonded magnet are provided in the magnet hole 11b, the proportion of magnetic material in the permanent magnet 12 can be increased. In addition, when the compression-bonded magnet 12a and the injection-bonded magnet 12b are provided in the magnet hole 11b, considering the simplification of the manufacturing process, after the compression-bonded magnet 12a is formed by compression molding in the magnet hole 11b, the injection-bonded magnet 12b is formed in the gap in the magnet hole 11b where the compression-bonded magnet 12a is not disposed, in such a way that it is adjacent to the compression-bonded magnet 12a. In other words, in the bonded magnet constituting the permanent magnet 12, the bonded magnet (compression bonded magnet 12a) first formed in the magnet hole 11b is compressed and molded, thus reducing the differences in shape and weight of the compression bonded magnet 12a in each of the magnet holes 11b. Furthermore, unlike sintered magnets, the compression bonded magnet 12a does not require heat treatment to optimize the crystal structure or surface finishing to roughen the surface, thus simplifying the manufacturing process. As a result, when the permanent magnet 12 is composed of bonded magnets, it is possible to prevent the complication of the manufacturing process and improve motor performance.

[0056] Furthermore, in the first embodiment, the compression-bonded magnet 12a is disposed inside the magnet hole portion 11b. That is, the magnet hole portion 11b is disposed inside the magnet hole portion 11b in a manner that separates from the sidewall of the magnet hole portion 11b. The injection-bonded magnet 12b is configured to surround the compression-bonded magnet 12a within the magnet hole portion 11b. Thus, unlike the injection-bonded magnet 12b, the compression-bonded magnet 12a has gaps generated during compression molding, so it is prone to rust if left exposed. However, by surrounding the compression-bonded magnet 12a with the injection-bonded magnet 12b, the rusting of the compression-bonded magnet 12a can be prevented.

[0057] Furthermore, even if the ratio of magnetic materials differs between the compression-bonded magnet 12a and the injection-bonded magnet 12b—for example, in the case of a combination of sintered magnets and (configured to surround) bonded magnets—the difference in the ratio of magnetic materials will not be significant. Therefore, it is not necessary to consider the magnetic balance, weight balance, etc., of the rotor core 10 when designing the rotor core 10.

[0058] Furthermore, in the first embodiment, the compression-bonded magnet 12a has a rectangular shape when viewed from the axial (Z direction) direction of the rotor core 10. Specifically, each of the two magnet holes 11b arranged in a V-shape adjacent to each other has a rectangular compression-bonded magnet 12a. Therefore, compared to the case where the compression-bonded magnet 12a has a complex shape, the compression-bonded magnet 12a can be arranged more evenly in the circumferential direction. As a result, it is easier to prevent a decrease in magnetic balance in the rotor core 10 and a reduction in motor performance.

[0059] Furthermore, in the first embodiment, the volume ratio of magnetic material to compression molding resin material in the compression-bonded magnet 12a is higher than the volume ratio of magnetic material to injection molding resin material in the injection-bonded magnet 12b. Specifically, the proportion of magnetic material in the compression-bonded magnet 12a is 70 vol% to 90 vol% or less. Conversely, the proportion of magnetic material in the injection-bonded magnet 12b is 40 vol% to 80 vol% or less. Therefore, compared to the case where all the bonded magnets are injection-bonded magnets, the proportion of magnetic material in the permanent magnet 12 can be reliably increased.

[0060] The difference between the volume ratio of the magnetic material in the compression-bonded magnet 12a to the volume ratio of the compression-molding resin material and the volume ratio of the magnetic material in the injection-bonded magnet 12b to the injection-molding resin material is preferably 20% or less. For example, the volume ratio of the magnetic material in the compression-bonded magnet 12a to the compression-molding resin material is 70% to 90%, and the volume ratio of the magnetic material in the injection-bonded magnet 12b to the injection-molding resin material is 50% to 80%. Therefore, as shown in the simulation results below, torque pulsation and excessive cogging torque can be prevented. That is, the instability of torque and the resulting decrease in motor performance can be prevented.

[0061] Torque pulsation is the variation (pulsation) of torque when the rotor 2 rotates due to the flow of current in the coil 3b of the stator 3. It is caused by the interaction between the magnetic flux generated by the current flowing in the coil 3b and the magnetic flux induced by the permanent magnet 12 of the rotor 2, which varies (is not constant) according to the rotation angle of the rotor 2. Additionally, cogging torque is the jittering torque felt when the rotor 2 is rotated externally when there is no current flowing in the coil 3b of the stator core 3a of the stator 3. It is caused by the change in the magnetic attraction between the stator 3 and the rotor 2 due to the change in the relationship between the salient poles of the stator 3 and the N / S poles of the rotor 2 as the rotor 2 rotates.

[0062] <Simulation Results>

[0063] like Figure 3A As shown, when the proportion of magnetic material in the injection-bonded magnet 12b is set to 50%, and the proportion of magnetic material in the compression-bonded magnet 12a is varied, when the proportion of magnetic material in the compression-bonded magnet 12a is less than 70%, the magnitude of torque pulsation is distributed along the proportional line (the dashed line in the figure) in a manner approximately proportional to the magnitude of the torque. On the other hand, when the proportion of magnetic material in the compression-bonded magnet 12a is greater than 70%, as the proportion of magnetic material in the compression-bonded magnet 12a increases, the magnitude of torque pulsation is distributed away from the proportional line. That is, when the proportion of magnetic material in the injection-bonded magnet 12b is set to 50%, and the proportion of magnetic material in the compression-bonded magnet 12a is greater than 70%, the magnitude of torque pulsation becomes excessive relative to the magnitude of the torque. Furthermore, as... Figure 3B As shown, when the proportion of magnetic material in the injection-bonded magnet 12b is set to 50%, and the proportion of magnetic material in the compression-bonded magnet 12a is varied, when the proportion of magnetic material in the compression-bonded magnet 12a is 70% or less, the cogging torque is distributed along the proportional line (dashed line in the figure) in a manner approximately proportional to the magnitude of the torque. On the other hand, when the proportion of magnetic material in the compression-bonded magnet 12a is greater than 70%, the magnitude of the cogging torque is distributed gradually away from the proportional line as the proportion of magnetic material in the compression-bonded magnet 12a increases. That is, when the proportion of magnetic material in the injection-bonded magnet 12b is set to 50%, and the proportion of magnetic material in the compression-bonded magnet 12a is greater than 70%, the magnitude of the cogging torque becomes excessive relative to the magnitude of the torque. Therefore, by setting the proportion of magnetic material in the injection-bonded magnet 12b to 50% and setting the proportion of magnetic material in the compression-bonded magnet 12a to 70% or less, torque pulsation and excessive cogging torque can be prevented. Furthermore, the torque in Figure 3 refers to the average value of the stable torque.

[0064] like Figure 3CAs shown, when the proportion of magnetic material in the injection-bonded magnet 12b is set to 60%, and the proportion of magnetic material in the compression-bonded magnet 12a is varied, when the proportion of magnetic material in the compression-bonded magnet 12a is less than 80%, the magnitude of the torque pulsation is distributed along the proportional line (the dashed line in the figure) in a manner approximately proportional to the magnitude of the torque. On the other hand, when the proportion of magnetic material in the compression-bonded magnet 12a is greater than 80%, as the proportion of magnetic material in the compression-bonded magnet 12a increases, the magnitude of the torque pulsation is distributed away from the proportional line. That is, when the proportion of magnetic material in the injection-bonded magnet 12b is set to 60%, and the proportion of magnetic material in the compression-bonded magnet 12a is greater than 80%, the magnitude of the torque pulsation becomes excessive relative to the magnitude of the torque. Furthermore, as... Figure 3D As shown, when the proportion of magnetic material in the injection-bonded magnet 12b is set to 60%, and the proportion of magnetic material in the compression-bonded magnet 12a is varied, when the proportion of magnetic material in the compression-bonded magnet 12a is 80% or less, the cogging torque is distributed along the proportional line (dashed line in the figure) in a manner approximately proportional to the magnitude of the torque. On the other hand, when the proportion of magnetic material in the compression-bonded magnet 12a is greater than 80%, the magnitude of the cogging torque is distributed gradually away from the proportional line as the proportion of magnetic material in the compression-bonded magnet 12a increases. That is, when the proportion of magnetic material in the injection-bonded magnet 12b is set to 60%, and the proportion of magnetic material in the compression-bonded magnet 12a is greater than 80%, the magnitude of the cogging torque becomes excessive relative to the magnitude of the torque. Therefore, by setting the proportion of magnetic material in the injection-bonded magnet 12b to 60% and setting the proportion of magnetic material in the compression-bonded magnet 12a to 80% or less, torque pulsation and excessive cogging torque can be prevented.

[0065] like Figure 3E As shown, when the proportion of magnetic material in the injection-bonded magnet 12b is set to 70%, and the proportion of magnetic material in the compression-bonded magnet 12a is varied, when the proportion of magnetic material in the compression-bonded magnet 12a is less than 90%, the magnitude of the torque pulsation is distributed along the proportional line (the dashed line in the figure) in a manner approximately proportional to the magnitude of the torque. On the other hand, when the proportion of magnetic material in the compression-bonded magnet 12a is greater than 90%, as the proportion of magnetic material in the compression-bonded magnet 12a increases, the magnitude of the torque pulsation is distributed in a manner gradually moving away from the proportional line. That is, when the proportion of magnetic material in the injection-bonded magnet 12b is set to 70%, and the proportion of magnetic material in the compression-bonded magnet 12a is greater than 90%, the magnitude of the torque pulsation becomes excessive relative to the magnitude of the torque. Furthermore, as... Figure 3F As shown, when the proportion of magnetic material in the injection-bonded magnet 12b is set to 70%, and the proportion of magnetic material in the compression-bonded magnet 12a is varied, when the proportion of magnetic material in the compression-bonded magnet 12a is 90% or less, the cogging torque is distributed along the proportional line (dashed line in the figure) in a manner approximately proportional to the magnitude of the torque. On the other hand, when the proportion of magnetic material in the compression-bonded magnet 12a is greater than 90%, the magnitude of the cogging torque is distributed away from the proportional line as the proportion of magnetic material in the compression-bonded magnet 12a increases. That is, when the proportion of magnetic material in the injection-bonded magnet 12b is set to 70%, and the proportion of magnetic material in the compression-bonded magnet 12a is greater than 90%, the magnitude of the cogging torque becomes excessive relative to the magnitude of the torque. Therefore, by setting the proportion of magnetic material in the injection-bonded magnet 12b to 70% and setting the proportion of magnetic material in the compression-bonded magnet 12a to 90% or less, torque pulsation and excessive cogging torque can be prevented.

[0066] Furthermore, in the first embodiment, the volume ratio of the compression-bonded magnet 12a in the permanent magnet 12 is greater than the volume ratio of the injection-bonded magnet 12b in the permanent magnet 12. Specifically, the injection-bonded magnet 12b is formed by injection molding in a manner where the compression-bonded magnet 12a is disposed in the magnet hole 11b in a way that occupies most of the magnet hole 11b, and the injection-bonded magnet 12b is embedded in the gap in the magnet hole 11b where the compression-bonded magnet 12a is not disposed. As a result, the volume ratio of the compression-bonded magnet 12a, which can increase the proportion of magnetic material compared to the injection-bonded magnet 12b, in the permanent magnet 12 can become larger, so the proportion of magnetic material in the permanent magnet 12 can be effectively increased.

[0067] Resin materials used for compression molding are thermosetting resin materials. Resin materials used for injection molding are either thermosetting or thermoplastic resin materials. Examples of thermosetting resin materials are epoxy resins. Examples of thermoplastic resin materials are polyphenylene sulfide (PPS), nylon, etc.

[0068] Here, thermoplastic resin materials reversibly change between solid and liquid states, with a melt temperature (e.g., 290°C in the case of PPS). On the other hand, thermosetting resin materials are either solid or liquid at room temperature. Furthermore, thermosetting resin materials maintain a molten state above the melt temperature but below a curing temperature higher than the melt temperature (e.g., 120°C to 150°C in the case of epoxy resin). Additionally, thermosetting resin materials are cured by heating to a temperature higher than the curing temperature. Moreover, once cured, thermosetting resin materials maintain their cured state (irreversible change) regardless of temperature.

[0069] Furthermore, thermoplastic resin materials and thermosetting resin materials undergo thermal decomposition (causing defects in the polymer skeleton through oxidation reactions) at decomposition temperatures higher than the melting temperature (e.g., 500°C in the case of PPS) and decomposition temperatures higher than the curing temperature (e.g., 250°C to 350°C in the case of epoxy resin), respectively. Therefore, when compression molding material 61a (refer to Figure 6) containing compression molding resin material and injection molding material 61b (refer to Figure 3) containing injection molding resin material are simultaneously heated (as described later in the injection molding step S140 of the rotor core 10 manufacturing method), (refer to...) Figure 5 The compression molding material 61a and the injection molding material 61b should be selected in a manner that does not exceed the above-mentioned decomposition temperature.

[0070] For example, in the injection molding material 61b included as the injection-bonded magnet 12b (see reference) Figure 4 When PPS is chosen as the thermoplastic resin material, its melt temperature is 290°C as described above. Therefore, in order to melt it during injection molding, it needs to be heated to a temperature above 290°C. In this case, the compression bonding magnet 12a, which is heated simultaneously, is preferably a compression bonding magnet made of a thermosetting resin material with a decomposition temperature greater than 290°C. Therefore, it is difficult to choose epoxy resin, which has a decomposition temperature of 250°C to 350°C as described above, as the thermosetting resin material heated simultaneously with PPS. Furthermore, the temperature difference between thermosetting resin materials is smaller than the difference between thermosetting resin materials and thermoplastic resin materials. Therefore, thermosetting resin materials are easier to handle as injection molding materials 61b than thermoplastic resin materials.

[0071] (Detailed structure of the fixture)

[0072] Next, refer to Figure 2The fixture 20 used for manufacturing the rotor core 10 of the first embodiment will be described. The fixture 20 is provided in the injection molding step S140 (injection bonding magnet molding step) of the rotor core 10 manufacturing process, which will be described later, to maintain the state of pressing the stacked core 11. Furthermore, the structure of the fixture 20 in which the stacked core 11 is positioned will be described below.

[0073] like Figure 2 As shown, the clamp 20 includes an upper plate 21, a pressing spring 22, a pressing plate 23, a lower plate 24, a heat insulation component 25, a positioning plate 26, and a clamping component 27. Furthermore, the upper plate 21, the pressing plate 23, the lower plate 24, and the positioning plate 26 are all made of SUS (stainless steel).

[0074] Viewed from the Z direction, the upper plate 21 has a through hole 21a at its center, forming a circular shape. Additionally, the upper plate 21 includes a plurality of resin injection holes 21b. The resin injection holes 21b are configured as the resin injection device 30 described later (see reference). Figure 4 Mold nozzle 122 (refer to) Figure 4 It can be inserted. In addition, when viewed from the Z direction, the resin injection hole 21b is set to overlap with each of the plurality of (32) magnet holes 11b.

[0075] The pressing spring 22 is disposed between the upper plate 21 and the pressing plate 23. Multiple pressing springs 22 are disposed at equal angular intervals along the C direction when viewed from the Z direction. Multiple (four) pressing springs 22 are disposed in the clamp 20. Each of the multiple (four) pressing springs 22, when the stacked iron core 11 is positioned overlapping the stacked iron core 11 when viewed from the Z1 side, with the stacked iron core 11 disposed in the clamp 20.

[0076] The pressing plate 23 is disposed on the upper end face 11c of the laminated iron core 11. The pressing plate 23 is configured to press the upper end face 11c of the laminated iron core 11 using the force of the pressing spring 22.

[0077] Viewed from the Z direction, the pressing plate 23 has a through hole 23a at its center, forming a ring shape. Additionally, the pressing plate 23 includes a plurality of resin injection holes 23b. Viewed from the Z1 side, the plurality of resin injection holes 23b are positioned overlapping with the plurality of resin injection holes 21b of the upper plate 21. Furthermore, the plurality of resin injection holes 23b are configured as the resin injection device 30 described later (see reference). Figure 4 Mold nozzle 122 (refer to) Figure 4 It can be inserted.

[0078] The lower plate 24 contacts the lower end face 11d of the laminated iron core 11. That is, the laminated iron core 11 is disposed (placed) on the lower plate 24. Viewed from the Z direction, the lower plate 24 has a through hole 24a at its center, forming an annular shape. Furthermore, the lower plate 24 includes multiple (three) cutouts 24b. The multiple cutouts 24b are arranged at approximately equal angular intervals along the inner periphery of the through hole 24a. Each of the multiple cutouts 24b has an L-shaped positioning part 24c. The positioning parts 24c determine the position of the laminated iron core 11 relative to the lower plate 24 in the R and C directions. The positioning parts 24c are fixed (fastened) to the lower plate 24 by fastening bolts 24d.

[0079] The heat insulation component 25 is positioned between the lower plate 24 and the positioning plate 26. Viewed from the Z-direction, the heat insulation component 25 has a through hole 25a at its center, forming a ring shape. Furthermore, the heat insulation component 25 is made of resin.

[0080] Positioning plate 26 is disposed on the Z2 side of the lower plate 24. Positioning plate 26 is used for positioning the clamp 20 of resin injection device 30.

[0081] The clamping member 27 has a U-shape and is configured to clamp the upper plate 21 and the lower plate 24. Thus, the upper plate 21 and the lower plate 24 clamp and press the stacked iron core 11. That is, the stacked iron core 11 is pressed by the clamp 20. Multiple (four) clamping members 27 are provided. Viewed from the Z direction, the multiple (four) clamping members 27 are arranged at approximately equal angular intervals (i.e., 90-degree intervals) along the C direction.

[0082] (Detailed structure of the resin injection device)

[0083] Next, refer to Figure 4 The detailed structure of the resin injection device 30 will be described below. In the injection molding process S140 (injection bonding magnet molding process) of the rotor core 10 manufacturing process described later, the resin injection device 30 is used to inject resin into the magnet hole 11b (see reference 11b). Figure 2 ) Injection of molten material 61b for injection molding (refer to) Figure 4 The resin injection device 30 is an injection molding machine.

[0084] like Figure 4 As shown, the resin injection device 30 includes a plasticizing unit 110 and a mold nozzle 122.

[0085] The plasticizing unit 110 includes a plasticizing cylinder 111. The plasticizing cylinder 111 has a cylindrical shape. A resin inlet 112 is provided at the root side of the plasticizing cylinder 111. Furthermore, solid or liquid injection molding material 61b is injected into the interior of the plasticizing cylinder 111 through the resin inlet 112.

[0086] A heating device 113 is provided on the outside of the plasticizing cylinder 111. The heating device 113 heats the plasticizing cylinder 111 so that the temperature of the injection molding material 61b injected into the plasticizing cylinder 111 is above the melt temperature in the case of thermoplastic resin materials, and above the melt temperature and below the curing temperature in the case of thermosetting resin materials. In addition, the injection molding material 61b is also heated by rotating in the screw portion 114, which will be described later.

[0087] A screw section 114 is provided inside the plasticizing cylinder 111. The screw section 114 is rotated by a drive device (not shown). The screw section 114 rotates about the central axis of the cylindrical plasticizing cylinder 111. Furthermore, by rotating the screw section 114, the molten injection molding material 61b is transferred towards the front end of the plasticizing cylinder 111.

[0088] The plasticizing unit 110 includes a manifold section 115. The manifold section 115 is provided at the front end of the plasticizing cylinder 111. A plunger section 116 having a cylinder body 116a and a piston 116b is provided in the manifold section 115. The cylinder body 116a is formed into a cylindrical shape. The interior of the plasticizing cylinder 111 and the interior of the cylinder body 116a are connected by a manifold internal flow path 115a extending in the Z direction. The interior of the cylinder body 116a is connected to the manifold internal flow path 115a at approximately the center of the manifold internal flow path 115a extending in the Z direction.

[0089] The piston 116b, viewed axially from the cylinder body 116a, has a circular outer peripheral surface. The piston 116b is configured to move axially within the cylinder body 116a. When the piston 116b retracts (moves to the side opposite to the manifold flow path 115a), the molten injection molding material 61b flowing in the manifold flow path 115a is filled into the interior of the cylinder body 116a. Conversely, when the piston 116b advances (moves towards the manifold flow path 115a), the injection molding material 61b filled into the cylinder body 116a is injected into the manifold flow path 115a. The injection molding material 61b injected into the manifold flow path 115a flows toward the injection nozzle 117 located at the front end (Z2 side) of the manifold flow path 115a.

[0090] The injection nozzle 117 is configured to supply the injection molding material 61b, injected from the cylinder 116a into the manifold flow path 115a, to the mold section 120 located on the Z2 side of the plasticizing unit 110, via the advancement of the piston 116b. Furthermore, the manifold section 115 is heated in the same manner as the plasticizing cylinder 111, so that the temperature of the injection molding material 61b housed inside the manifold section 115 is above the melting temperature in the case of thermoplastic resin materials, and above the melting temperature and below the curing temperature in the case of thermosetting resin materials.

[0091] An injection valve pin 118 is provided in the flow path 115a within the manifold. The injection valve pin 118 is open when the injection molding material 61b is ejected from the injection nozzle 117. Conversely, the injection valve pin 118 is closed when the injection molding material 61b is not ejected from the injection nozzle 117. Furthermore, Figure 4 The diagram shows the injection valve pin 118 in the closed state.

[0092] The mold section 120 is configured to supply injection molding material 61b from the plasticizing unit 110. A flow path 121 for the injection molding material 61b is provided inside the mold section 120. The flow path 121 branches into multiple in-mold flow paths 121a toward the stacked iron core 11. Furthermore, the in-mold nozzle flow path 121b of each flow path 121 connected to the in-mold flow path 121a on the stacked iron core 11 side (Z2 side) is positioned corresponding to the magnet hole portion 11b of the stacked iron core 11.

[0093] A mold nozzle 122 is provided in the mold section 120. The mold nozzle 122 is located at the front end of the flow path 121 (the flow path 121b inside the mold nozzle). When injection molding material 61b is injected into the magnet hole 11b, the front end (the end on the Z2 side) of the injection nozzle 117 of the plasticizing unit 110 is connected to the hole 120a of the mold section 120 (located at the end opposite to the front end of the flow path 121). Moreover, with the front end of the injection nozzle 117 connected to the hole 120a of the mold section 120, the injection molding material 61b contained in the flow path 121 is squeezed by the injection molding material 61b supplied to the mold section 120 via the injection nozzle 117 and the piston 116b, and thereby injected from the mold nozzle 122 of the mold section 120 into the magnet hole 11b of the laminated iron core 11.

[0094] Furthermore, a mold valve 123 is provided in the flow path 121b within the mold nozzle. The mold valve 123 is open when the injection molding material 61b is ejected from the mold nozzle 122. Conversely, the mold valve 123 is closed when the injection molding material 61b is not ejected from the mold nozzle 122. The mold valve 123 also includes a mold valve pin 123a. The mold valve pin 123a blocks the tip 122a of the mold nozzle 122, thereby blocking the injection of the injection molding material 61b from the mold nozzle 122.

[0095] In addition, a mold temperature control device 124 is provided on the outside of the mold section 120. The mold temperature control device 124 heats the mold section 120 so that the temperature of the injection molding material 61b housed inside the mold section 120 is above the melting temperature in the case of thermoplastic resin materials, and above the melting temperature and below the curing temperature in the case of thermosetting resin materials.

[0096] (Manufacturing method of rotor core)

[0097] Next, refer to Figure 5 Figure 9 illustrates the manufacturing method of the rotor core 10.

[0098] <Compression and bonding magnet molding process>

[0099] First, such as Figure 5 As shown, the compression-bonded magnet 12a (see Figure 6) is formed by compressing the material 61a (see Figure 6) into a compression-bonded form. Figure 2 The compression molding process S110 (compression bonding magnet molding process) is used for forming.

[0100] Specifically, such as Figure 6A As shown, the compression molding material 61a is supplied as powder to the compression molding die 62. Furthermore, as... Figure 6B As shown, while heating the compression molding material 61a to its melting temperature in a relatively slow manner, an electromagnet 63 applies a magnetic field 64 to the compression molding material 61a for magnetization orientation. As a result, since the temperature change of the compression molding material 61a is relatively small, the generation of thermal stress in the compression molding material 61a can be suppressed.

[0101] Moreover, such as Figure 6CAs shown, the compression molding material 61a is heated and pressurized at a temperature above the melting temperature and below the curing temperature of the thermosetting compression molding resin material, while a magnetic field 64 is maintained on the compression molding material 61a. Thus, in the compression molding process S110, the compression molding material 61a is in a state of being uncured (thermosetting) but hardened (powdered) and magnetized and oriented. That is, in the first embodiment, the compression molding process S110 is a process in which the thermosetting compression molding material 61a is compressed at a temperature that does not cure, thereby forming the compression bonded magnet 12a without curing.

[0102] Moreover, such as Figure 6D As shown, the compression-bonded magnet 12a, after being compressed and molded from the compression molding material 61a, is removed from the compression molding mold 62. At this time, the compression-bonded magnet 12a is not solidified (it is a compressed powder), so in order to prevent the compression-bonded magnet 12a from collapsing, it is either clamped in a manner that surrounds the entire compression-bonded magnet 12a, or it is allowed to adhere to a magnet clamp while being removed from the compression molding mold 62.

[0103] <Layered Iron Core Forming Process>

[0104] Next, as Figure 5 As shown, the laminated iron core 11 (refer to) is then processed. Figure 2 The forming process S120 involves stacking multiple electromagnetic steel plates 11a (refer to...). Figure 2 ), forming a laminated iron core 11 (refer to Figure 2 At this time, through stamping, a magnet hole 11b extending along the stacking direction (Z direction) of the electromagnetic steel plate 11a is formed in the laminated iron core 11 (see reference). Figure 2 Furthermore, the order of the stacked core forming process S120 and the compression forming process S110 can also be reversed.

[0105] <Compression and bonding magnet preparation process>

[0106] Next, as Figure 5 As shown, a configuration step S130 (compression-bonded magnet configuration step) is performed, in which the compression-bonded magnet 12a (see Figure 7) is configured inside the magnet hole 11b of the rotor core 10. Specifically, as... Figure 2 As shown, firstly, the laminated core 11 is positioned (placed) on the lower plate 24 of the clamp 20 with the axial direction (Z direction) of the rotor core 10 as the vertical direction. Furthermore, as... Figure 7AAs shown, from below (Z2 side) of the magnet hole 11b, the magnet lowering pin 71, which moves vertically (Z direction) by means of an actuator that slides vertically (Z direction), is inserted into the magnet hole 11b. At this time, the magnet lowering pin 71 is inserted into the magnet hole 11b in such a way that the front end 71 of the magnet lowering pin 71 is moved inward a predetermined distance from the end 11e of the hole (Z2 side) of the magnet hole 11b. That is, in the first embodiment, the arrangement step S130 is to become the injection molding material 61b (see reference) for the injection compression bonded magnet 12a. Figure 4 The process involves placing the compression-bonded magnet 12a into the magnet hole 11b of the rotor core 10 in a manner where the magnet end 12c on the opposite side (Z1 side) of the magnet hole 11b moves away from the end 11e of the hole on the other side (Z2 side) of the magnet hole 11b towards the inner side of the rotor core 10 in the axial direction (Z direction). Furthermore, the magnet lower release pin 71 is an example of a "clamp" in the technical solution.

[0107] Moreover, such as Figure 7B As shown, with the stacked iron core 11 disposed on the lower plate 24 of the fixture 20, the compression-bonded magnet 12a is disposed in the magnet hole 11b. Furthermore, as... Figure 2 As shown, the lower plate 24 and upper plate 21 of the clamp 20 are clamped (connected) by the clamping member 27, and the upper end face 11c of the laminated iron core 11 is pressed by the pressing plate 23. Furthermore, in the manufacturing method of the rotor iron core 10, in the arrangement process S130 (see...) Figure 5 In the process of injection molding, after the laminated iron core 11 is placed in the fixture 20, in the injection molding process S140 (refer to...), Figure 5 Before the end, the stacked iron core 11 is pressed down by the clamp 20.

[0108] <Injection bonding magnet molding process>

[0109] Next, as Figure 5 As shown, the material 61b (refer to) for injection molding is passed through. Figure 4 Injection molding is performed by injecting the material into the magnet hole 11b, while the injection-bonded magnet 12b (refer to...) Figure 4 ) Molded in the magnet hole portion 11b (refer to) Figure 4 In the injection molding process S140 (injection bonding magnet molding process), there is no gap in the arrangement of the compression bond magnet 12a. Therefore, unlike the injection bond magnet 12b, the compression bond magnet 12a does not require fluidity to increase the proportion of magnetic material. Thus, compared to the case where the second injection bond magnet is formed without a gap in the magnet hole 11b to accommodate the first injection bond magnet, the permanent magnet 12 (see reference) can be increased in size. Figure 4The proportion of magnetic material in the permanent magnet 12 is adjusted. Furthermore, in the bonded magnet constituting the permanent magnet 12, the bonded magnet (compression bonded magnet 12a) first formed within the magnet hole 11b is formed by compression molding, thus reducing the differences in shape and weight of the compression bonded magnet 12a in each of the magnet holes 11b. Moreover, unlike sintered magnets, compression bonded magnets 12a do not require heat treatment to optimize the crystal structure or surface finishing to roughen the surface, thus simplifying the manufacturing process. As a result, when the permanent magnet 12 is composed of bonded magnets, it is possible to prevent the complication of the manufacturing process and improve motor performance.

[0110] Furthermore, in the first embodiment, the injection molding process S140 involves surrounding the magnet hole portion 11b (see reference). Figure 4 Compression bonded magnet 12a (refer to) Figure 4 In a manner that involves using injection molding material 61b (refer to) Figure 4 The injection-bonded magnet 12b is injection molded by injecting into the magnet hole 11b (see reference). Figure 4 The molding process. Thus, the compression-bonded magnet 12a and the injection-bonded magnet 12b (refer to...) Figure 4 Unlike compression molding, where gaps are created during compression molding and the magnet is easily exposed, injection molding surrounds the compression-bonded magnet 12a with the injection-bonded magnet 12b, thus preventing the compression-bonded magnet 12a from rusting. As a result, even with the permanent magnet 12 (see reference...), rust is prevented. Figure 4 If a compression bonded magnet 12a is used as part of the process, then a rust-proofing process for the compression bonded magnet 12a is not required.

[0111] Furthermore, the injection molding material 61b used in the injection molding process S140 includes either a magnetic material and a thermosetting resin material, or a magnetic material and a thermoplastic resin material. Therefore, even when using an injection molding material 61b that includes either a thermosetting resin material or a thermoplastic resin material, it is possible to mold the injection-bonded magnet 12b.

[0112] Additionally, as shown in Figure 8, in the first embodiment, the injection molding process S140 is performed by passing through the fixture 20 (see Figure 8). Figure 2The process involves injecting injection molding material 61b into the magnet hole 11b in a manner where the magnet end 12c in the compression bond magnet 12a is separated from the end 11e of the hole in the magnet hole 11b in the axial (Z direction) inward. This material is then injected around the end 11e of the hole in the magnet hole 11b (viewed from the side where the injection molding material 61b is injected, the inside of the magnet hole 11b is on the Z2 side). Because the injection molding material 61b is injected around the inside of the compression bond magnet 12a when viewed from the injected side, the injection bond magnet 12b can be easily molded to surround the compression bond magnet 12a.

[0113] Specifically, such as Figure 8A As shown, firstly, the mold nozzle 122 of the resin injection device 30 is positioned at the resin injection hole 23b (refer to...). Figure 2 (Mold closed). This results in a state where the injection molding material 61b can be injected into the magnet hole 11b via the resin injection device 30. Furthermore, as... Figure 8B As shown, heated and molten injection molding material 61b is injected from the resin injection device 30 into the magnet hole 11b, which is equipped with a compression bonding magnet 12a. At this time, an electromagnet 72 is used to apply a magnetic field 73 for magnetization and orientation to the injection molding material 61b.

[0114] Moreover, such as Figure 8C As shown, while maintaining the magnetic field 73 applied to the injection molding material 61b, after the injection molding material 61b reaches the lower side (Z2 side) of the magnet hole 11b, the magnet lower release pin 71 is retracted downwards (Z2 side) (retracting from the magnet hole 11b). Furthermore, during the stage of retracting the magnet lower release pin 71 downwards (Z2 side), the injection molding material 61b does not solidify. However, a relatively high pressure is applied to the injection molding material 61b after injection molding via the resin injection device 30, and the difference between the specific gravity of the compression bond magnet 12a and the specific gravity of the injection molding material 61b (injection bond magnet 12b) is relatively small. Therefore, even when the magnet lower release pin 71 is retracted downwards (Z2 side), the compression bond magnet 12a is maintained in a state of being separated from the lower end of the magnet hole 11b (it does not sink into the injection molding material 61b towards the Z2 side).

[0115] Moreover, such as Figure 8DAs shown, while maintaining the magnetic field 73 applied to the injection molding material 61b, the injection molding material 61b injected into the magnet hole 11b in a manner surrounding the compression-bonded magnet 12a (if the injection molding material 61b is made of a thermoplastic resin material) cures or (if the injection molding material 61b is made of a thermosetting resin material) cures. At this time, the compression-bonded magnet 12a, which was not cured in the compression molding process S110, also cures simultaneously.

[0116] Specifically, when using injection molding material 61b containing magnetic material and thermosetting resin material, the compression bonding magnet 12a, which is a powder compactor, is maintained in the magnet hole portion 11b at a temperature below the curing temperature of the thermosetting resin material contained in the compression bonding magnet 12a (e.g., 120°C to 150°C in the case of epoxy resin). In the resin injection device 30, the injection molding material 61b is maintained at a temperature above the melting temperature of the thermosetting resin material contained in the injection molding material 61b and below the curing temperature of the thermosetting resin material contained in the injection molding material 61b (e.g., 120°C to 150°C in the case of epoxy resin). Furthermore, approximately simultaneously with the injection molding material 61b being injected into the magnet hole 11b, the temperature of both the injection molding material 61b and the compression-bonded magnet 12a is adjusted to a temperature higher than the curing temperature of the thermosetting resin material contained in the injection molding material 61b (e.g., 120°C to 150°C in the case of epoxy resin) and the curing temperature of the thermosetting resin material contained in the compression-bonded magnet 12a (e.g., 120°C to 150°C in the case of epoxy resin). Thus, the compression-bonded magnet 12a, containing thermosetting resin material, cures approximately simultaneously with the curing of the injection molding material 61b containing thermosetting resin material.

[0117] Furthermore, when using injection molding material 61b, which contains magnetic material and thermoplastic resin material, the compression-bonded magnet 12a, as a powder compactor, is maintained in the magnet hole portion 11b at a temperature below the curing temperature of the thermosetting resin material contained in the compression-bonded magnet 12a (e.g., 120°C to 150°C in the case of epoxy resin), and the injection molding material 61b is maintained in the resin injection device 30 at a temperature higher than the melting temperature of the thermoplastic resin material contained in the injection molding material 61b (e.g., 290°C in the case of PPS). The melting temperature of the thermoplastic resin material contained in the injection molding material 61b (e.g., 290°C in the case of PPS) is higher than the curing temperature of the thermosetting resin material contained in the compression-bonded magnet 12a (e.g., 120°C to 150°C in the case of epoxy resin). Furthermore, approximately simultaneously with the injection molding material 61b being injected into the magnet hole 11b, the temperature is adjusted so that both the injection molding material 61b and the compression-bonded magnet 12a are at a temperature higher than the curing temperature of the thermosetting resin material contained in the compression-bonded magnet 12a (e.g., 120°C to 150°C in the case of epoxy resin) and lower than the melting temperature of the thermoplastic resin material contained in the injection molding material 61b (e.g., 290°C in the case of PPS). Thus, the thermosetting resin material of the compression-bonded magnet 12a cures approximately simultaneously with the curing of the thermoplastic resin material of the injection molding material 61b.

[0118] In the first embodiment, the injection molding process S140 involves molding the injection-bonded magnet 12b by injecting the material 61b into the magnet hole 11b at a temperature that cures together with the compression-bonded magnet 12a after compression molding without curing, so that it cures together with the curing of the compression-bonded magnet 12a. Therefore, the curing of the compression-bonded magnet 12a and the injection-bonded magnet 12b can be performed in a single heating cycle, thus reducing the time required compared to performing separate heating cycles for curing the compression-bonded magnet 12a and for curing the injection-bonded magnet 12b.

[0119] Furthermore, approximately simultaneously with the curing or hardening of the injection molding material 61b, after the compression-bonded magnet 12a has cured, a permanent magnet 12 (unmagnetized) consisting of the compression-bonded magnet 12a and the injection-bonded magnet 12b is formed. Then, the permanent magnet 12 is cooled. Moreover, as... Figure 9A As shown, the application of the magnetic field 73 of the electromagnet 72 to the injection molding material 61b is stopped, and the mold nozzle 122 of the resin injection device 30 is opened from the resin injection hole 23b (see reference). Figure 2 Remove (the mold). Then, as... Figure 9BAs shown, an actuator positioned below (Z2 side) of the stacked iron core 11 and sliding in the vertical direction (Z direction) causes the iron core lower release pin 74, which moves in the vertical direction (Z direction), to press the stacked iron core 11 from below (Z2 side), thereby removing the stacked iron core 11 from the clamp 20. Simultaneously with the iron core lower release pin 74, the magnet lower release pin 71 presses the permanent magnet 12 from below (Z2 side). Then, as... Figure 9C As shown, the stacked iron core 11 is removed from the fixture 20.

[0120] <Permanent magnet magnetization process>

[0121] Next, as Figure 5 as well as Figure 9D As shown, a magnetization process S150 (permanent magnet magnetization process) is performed to magnetize the adhesive magnet 12, which is a permanent magnet disposed in the magnet hole portion 11b.

[0122] [Second Implementation]

[0123] Reference Figure 10 Figure 11 illustrates the structure of the rotor core 210 of the second embodiment.

[0124] (Structure of a rotary electric machine)

[0125] First, refer to Figure 10 The structure of the rotary electric motor 201, which is equipped with a rotor core 210, will be described.

[0126] like Figure 10 As shown, the rotary motor 201 includes a rotor 202. The rotor 202 includes a rotor core 210.

[0127] (Structure of the rotor core)

[0128] Next, refer to Figure 10 Figure 11 illustrates the structure of the rotor core 210.

[0129] like Figure 10 As shown, the rotor core 210 has magnet holes 211b. Multiple (16) magnet holes 211b are provided in the rotor core 210. Each magnet hole 211b has a crescent shape protruding towards the R1 side.

[0130] The rotor core 210 has a permanent magnet 212. The permanent magnet 212 is housed (configured) in the magnet hole 211b.

[0131] In the second embodiment, the permanent magnet 212 includes a compression-bonded magnet 212a and an injection-bonded magnet 212b. The injection-bonded magnet 212b is disposed in the gap in the magnet hole 211b where the compression-bonded magnet 212a is not disposed. That is, the injection-bonded magnet 212b is the same as in the first embodiment, and is disposed adjacent to the compression-bonded magnet 212a in the magnet hole 211b.

[0132] Furthermore, in the second embodiment, the compression-bonded magnet 212a is the same as in the first embodiment, and is disposed inside the magnet hole 211b. The injection-bonded magnet 212b is the same as in the first embodiment, and is configured to surround the compression-bonded magnet 212a in the magnet hole 211b.

[0133] On the other hand, in the second embodiment, the compression-bonded magnet 212a has a crescent shape when viewed from the axial (Z direction) direction of the rotor core 210. Specifically, one crescent-shaped compression-bonded magnet 212a is disposed in each of the crescent-shaped magnet holes 211b. Thus, similar to the first embodiment, compared to the case where the compression-bonded magnet 212a has a complex shape, the compression-bonded magnet 212a can be disposed more evenly in the circumferential direction. As a result, similar to the first embodiment, the magnetic balance of the rotor core 210 can be reduced, and the performance degradation of the rotary motor 201 can be prevented.

[0134] Furthermore, in the second embodiment, similar to the first embodiment, it is preferable that the difference between the volume ratio of the magnetic material in the compression bonded magnet 212a to the volume ratio of the compression molding resin material and the volume ratio of the magnetic material in the injection bonded magnet 212b to the injection molding resin material is 20% or less.

[0135] Therefore, as shown in the simulation results below, similar to the first embodiment, it is possible to prevent torque pulsation and excessive cogging torque. That is, similar to the first embodiment, it is possible to prevent the torque from becoming unstable and the motor performance from deteriorating.

[0136] <Simulation Results>

[0137] like Figure 11AAs shown, when the proportion of magnetic material in the injection-bonded magnet 212b is set to 50%, and the proportion of magnetic material in the compression-bonded magnet 212a is varied, when the proportion of magnetic material in the compression-bonded magnet 212a is less than 70%, the magnitude of the torque pulsation is distributed along the proportional line (the dashed line in the figure) in a manner approximately proportional to the magnitude of the torque. On the other hand, when the proportion of magnetic material in the compression-bonded magnet 212a is greater than 70%, as the proportion of magnetic material in the compression-bonded magnet 212a increases, the magnitude of the torque pulsation is distributed in a manner gradually moving away from the proportional line. That is, when the proportion of magnetic material in the injection-bonded magnet 212b is set to 50%, and the proportion of magnetic material in the compression-bonded magnet 212a is greater than 70%, the magnitude of the torque pulsation becomes excessive relative to the magnitude of the torque. Furthermore, as... Figure 11B As shown, when the proportion of magnetic material in the injection-bonded magnet 212b is set to 50%, and the proportion of magnetic material in the compression-bonded magnet 212a is varied, when the proportion of magnetic material in the compression-bonded magnet 212a is 70% or less, the cogging torque is distributed along the proportional line (dashed line in the figure) in a manner approximately proportional to the magnitude of the torque. On the other hand, when the proportion of magnetic material in the compression-bonded magnet 212a is greater than 70%, the magnitude of the cogging torque is distributed gradually away from the proportional line as the proportion of magnetic material in the compression-bonded magnet 212a increases. That is, when the proportion of magnetic material in the injection-bonded magnet 212b is set to 50%, and the proportion of magnetic material in the compression-bonded magnet 212a is greater than 70%, the magnitude of the cogging torque becomes excessive relative to the magnitude of the torque. Therefore, by setting the proportion of magnetic material in the injection-bonded magnet 212b to 50% and setting the proportion of magnetic material in the compression-bonded magnet 212a to 70% or less, torque pulsation and excessive cogging torque can be prevented.

[0138] like Figure 11CAs shown, when the proportion of magnetic material in the injection-bonded magnet 212b is set to 60%, and the proportion of magnetic material in the compression-bonded magnet 212a is varied, when the proportion of magnetic material in the compression-bonded magnet 212a is less than 80%, the magnitude of the torque pulsation is distributed along the proportional line (the dashed line in the figure) in a manner approximately proportional to the magnitude of the torque. On the other hand, when the proportion of magnetic material in the compression-bonded magnet 212a is greater than 80%, as the proportion of magnetic material in the compression-bonded magnet 212a increases, the magnitude of the torque pulsation is distributed in a manner gradually moving away from the proportional line. That is, when the proportion of magnetic material in the injection-bonded magnet 212b is set to 60%, and the proportion of magnetic material in the compression-bonded magnet 212a is greater than 80%, the magnitude of the torque pulsation becomes excessive relative to the magnitude of the torque. Furthermore, as... Figure 11D As shown, when the proportion of magnetic material in the injection-bonded magnet 212b is set to 60%, and the proportion of magnetic material in the compression-bonded magnet 212a is varied, when the proportion of magnetic material in the compression-bonded magnet 212a is 80% or less, the cogging torque is distributed along the proportional line (dashed line in the figure) in a manner approximately proportional to the magnitude of the torque. On the other hand, when the proportion of magnetic material in the compression-bonded magnet 212a is greater than 80%, the magnitude of the cogging torque is distributed away from the proportional line as the proportion of magnetic material in the compression-bonded magnet 212a increases. That is, when the proportion of magnetic material in the injection-bonded magnet 212b is set to 60%, and the proportion of magnetic material in the compression-bonded magnet 212a is greater than 80%, the magnitude of the cogging torque becomes excessive relative to the magnitude of the torque. Therefore, by setting the proportion of magnetic material in the injection-bonded magnet 212b to 60% and setting the proportion of magnetic material in the compression-bonded magnet 212a to 80% or less, torque pulsation and excessive cogging torque can be prevented.

[0139] like Figure 11EAs shown, when the proportion of magnetic material in the injection-bonded magnet 212b is set to 70%, and the proportion of magnetic material in the compression-bonded magnet 212a is varied, when the proportion of magnetic material in the compression-bonded magnet 212a is less than 90%, the magnitude of the torque pulsation is distributed along the proportional line (the dashed line in the figure) in a manner approximately proportional to the magnitude of the torque. On the other hand, when the proportion of magnetic material in the compression-bonded magnet 212a is greater than 90%, as the proportion of magnetic material in the compression-bonded magnet 212a increases, the magnitude of the torque pulsation is distributed in a manner gradually moving away from the proportional line. That is, when the proportion of magnetic material in the injection-bonded magnet 212b is set to 70%, and the proportion of magnetic material in the compression-bonded magnet 212a is greater than 90%, the magnitude of the torque pulsation becomes excessive relative to the magnitude of the torque. Furthermore, as... Figure 11F As shown, when the proportion of magnetic material in the injection-bonded magnet 212b is set to 70%, and the proportion of magnetic material in the compression-bonded magnet 212a is varied, when the proportion of magnetic material in the compression-bonded magnet 212a is 90% or less, the cogging torque is distributed along the proportional line (dashed line in the figure) in a manner approximately proportional to the magnitude of the torque. On the other hand, when the proportion of magnetic material in the compression-bonded magnet 212a is greater than 90%, the magnitude of the cogging torque is distributed gradually away from the proportional line as the proportion of magnetic material in the compression-bonded magnet 212a increases. That is, when the proportion of magnetic material in the injection-bonded magnet 212b is set to 70%, and the proportion of magnetic material in the compression-bonded magnet 212a is greater than 90%, the magnitude of the cogging torque becomes excessive relative to the magnitude of the torque. Therefore, by setting the proportion of magnetic material in the injection-bonded magnet 212b to 70% and the proportion of magnetic material in the compression-bonded magnet 212a to 90% or less, torque pulsation and excessive cogging torque can be prevented.

[0140] Furthermore, the other structures and effects of the second embodiment are largely the same as those of the first embodiment.

[0141] [Variation Example]

[0142] Furthermore, the embodiments disclosed herein should be considered merely illustrative and not restrictive in all respects. The scope of the invention is defined not by the description of the above embodiments but by the technical solutions, and therefore includes all equivalents and modifications within that scope.

[0143] For example, in the first and second embodiments described above, although an example is shown in which the injection molding material 61b and the compression-bonded magnet 12a (212a) that has not been cured in the compression molding step S110 are simultaneously cured in the injection molding step S140, the present invention is not limited thereto. In the present invention, the compression-bonded magnet may be cured in the compression molding step, or it may be cured after the compression molding step and between the injection molding step.

[0144] Furthermore, while examples have been shown in the first and second embodiments described above, in which the magnet lower release pin 71 and the iron core lower release pin 74 are moved in the vertical direction (Z direction) by an actuator that slides in the vertical direction, the present invention is not limited thereto. In the present invention, the magnet lower release pin and the iron core lower release pin may also be moved in the vertical direction by an actuator that slides in a direction other than the vertical direction (e.g., the horizontal direction).

[0145] Furthermore, although examples of the stacked core 11 being configured such that the axial direction (Z direction) of the rotor core 10 (210) is vertically aligned are shown in the first and second embodiments described above, the present invention is not limited thereto. In the present invention, the stacked core may also be configured such that the axial direction of the rotor core is in a direction other than vertically aligned.

[0146] Furthermore, although examples of resin injection devices 30 being injection molding machines have been shown in the first and second embodiments described above, the present invention is not limited thereto. In the present invention, the resin injection device may also be a transfer molding machine.

[0147] Furthermore, although examples of a plunger portion 116 having a cylinder 116a and a piston 116b being provided in the resin injection device 30 are shown in the first and second embodiments described above, the present invention is not limited thereto. In the present invention, the plunger portion having a cylinder and a piston may not be provided in the resin injection device, and the resin injection device may be configured to directly inject the adhesive magnet from the screw portion to the magnet hole portion, or the resin injection device may be configured to inject the adhesive magnet from the screw portion to the magnet hole portion via a mold portion connected to the screw portion.

[0148] Furthermore, although examples of one compression-bonded magnet 12a (212a) being disposed in each of the magnet holes 11b (211b) described above are shown, the present invention is not limited thereto. In the present invention, two or more compression-bonded magnets may also be disposed in the magnet holes.

[0149] Furthermore, although examples of the compression-bonded magnet 12a (212a) having a rectangular or crescent shape when viewed from the axial (Z direction) direction of the rotor core 10 (210) are shown in the first and second embodiments described above, the present invention is not limited to these. In the present invention, the compression-bonded magnet may also have a shape other than a rectangular or crescent shape when viewed from the axial direction of the rotor core.

[0150] Furthermore, although an example of two adjacent magnet holes 11b being arranged in a V-shape was shown in the first embodiment above, and an example of magnet holes 11b having a crescent shape was shown in the second embodiment above, the shape and arrangement of the magnet holes are not limited to these in the present invention.

[0151] Furthermore, although the first and second embodiments described above show an example where the compression-bonded magnet 12a (212a) is disposed inside the magnet hole portion 11b (211b) and the injection-bonded magnet 12b (212b) is configured to surround the compression-bonded magnet 12a (212a) within the magnet hole portion 11b (211b), the present invention is not limited thereto. In the present invention, the injection-bonded magnet may also be configured such that the compression-bonded magnet is not surrounded within the magnet hole portion.

[0152] Explanation of reference numerals in the attached figures

[0153] 10, 210… Rotor core, 11… Laminated core, 11b, 211b… Magnet hole, 11c… Hole end, 12, 212… Permanent magnet, 12a, 212a… Compression bonded magnet, 12b, 212b… Injection bonded magnet, 12c… Magnet end, 20… Fixture, 61a… Material containing magnetic material and compression molding resin material, 61b… Material containing magnetic material and injection molding resin material.

Claims

1. A rotor core comprising: A ring-shaped, stacked iron core, constructed by stacking multiple electromagnetic steel plates, and forming magnet holes; and A permanent magnet is disposed in the aforementioned magnet hole. The aforementioned permanent magnet includes a compression-bonded magnet and an injection-bonded magnet. The compression-bonded magnet includes a magnetic material and a compression molding resin material for bonding the particles of the magnetic material together, and is disposed in the magnet hole. The injection-bonded magnet includes the magnetic material and an injection molding resin material for bonding the particles of the magnetic material together, and is disposed adjacent to the compression-bonded magnet in the magnet hole.

2. The rotor core according to claim 1, wherein, The aforementioned compression-bonded magnet is disposed inside the aforementioned magnet hole. The aforementioned injection-bonded magnet is configured to surround the aforementioned compression-bonded magnet within the aforementioned magnet hole.

3. The rotor core according to claim 2, wherein, The aforementioned compressed adhesive magnet, when viewed from the axial direction of the aforementioned rotor core, has a rectangular or crescent shape.

4. The rotor core according to any one of claims 1 to 3, wherein, The volume ratio of the magnetic material in the compression bonded magnet to the compression molding resin material is higher than that in the injection bonded magnet to the injection molding resin material.

5. The rotor core according to claim 4, wherein, The difference between the volume ratio of the magnetic material in the compression bonded magnet to the volume ratio of the compression molding resin material and the volume ratio of the magnetic material in the injection bonded magnet to the volume molding resin material is 20% or less.

6. The rotor core according to claim 5, wherein, In the above-mentioned compression-bonded magnet, the volume ratio of the magnetic material to the compression molding resin material is 70% to 90%. The volume ratio of the magnetic material in the injection-bonded magnet to the resin material for injection molding is 50% to 80%.

7. The rotor core according to any one of claims 1 to 6, wherein, The volume ratio of the compression-bonded magnet in the aforementioned permanent magnet is greater than the volume ratio of the injection-bonded magnet in the aforementioned permanent magnet.

8. A method for manufacturing a rotor core, comprising a ring-shaped stacked core composed of multiple stacked electromagnetic steel plates and having magnet holes, and a permanent magnet disposed in the magnet holes, the method comprising the following steps: The compression molding process involves compressing a material containing magnetic material and a compression molding resin material for bonding the particles of the magnetic material together to form a compression bond magnet. In the configuration process, after the compression molding process described above, the compression-bonded magnet is disposed in the magnet hole portion of the rotor core; and In the injection molding process, after the above-mentioned configuration process, without the gap in the above-mentioned magnet hole where the above-mentioned compression bonded magnet is not configured, injection molding is performed by injecting a material containing the above-mentioned magnetic material and an injection molding resin material for bonding the particles of the above-mentioned magnetic material into the above-mentioned magnet hole, thereby molding the injection bonded magnet.

9. The method for manufacturing a rotor core according to claim 8, wherein, The compression molding process described above is a process of molding the compression-bonded magnet by compressing a material containing the thermosetting compression molding resin material. The above-mentioned injection molding process involves injecting a material containing either a thermosetting or thermoplastic injection molding resin into the magnet hole where there is no gap in the magnet hole where the compression bond magnet is disposed, thereby molding the injection bond magnet.

10. The method for manufacturing a rotor core according to claim 8 or 9, wherein, The above-described configuration process involves placing the compressed adhesive magnet inside the magnet hole of the rotor core. The above-mentioned injection molding process involves injecting a material containing the magnetic material and the injection molding resin material into the magnet hole to form the injection bonded magnet so as to surround the compression bonded magnet disposed in the magnet hole.

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