Method for manufacturing a magnetic field

Abstract

To provide a manufacturing method of a field magnet capable of properly magnetizing each magnet in the field magnet.SOLUTION: A manufacturing method of a rotor 10 having multiple magnets 15 that form different magnetic poles in the circumferential direction includes: a first magnetizing step of generating a magnetizing magnetic field by a magnetizing device 20, and using the magnetizing magnetic field, magnetizing all the magnets 15 arranged in an annular shape; and a second magnetizing step of generating, after the first magnetizing step, generating a magnetizing magnetic field stronger than that in the first magnetizing step by the magnetizing device 20, and using the magnetizing magnetic field, sequentially magnetizing every predetermined number of magnets 15 out of all the magnets 15 arranged in the annular shape in the circumferential direction.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The disclosure in this specification relates to a method for manufacturing a field magnet.

Background Art

[0002] In a rotating electrical machine, in a field magnet having a plurality of magnets for forming different magnetic poles in the circumferential direction, magnetization is performed on each magnet during its manufacturing. For example, a method of collectively magnetizing all the magnets arranged in a circumferential direction in the field magnet is known (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As a method of magnetizing each magnet of the field magnet, in addition to the above-described collective magnetization, it is conceivable to divide all the magnets arranged in the circumferential direction into plural groups and perform magnetization for each of the plural groups of magnets. However, when performing magnetization by dividing all the magnets into plural groups, if leakage magnetic flux occurs from the magnetization area including the magnet to be magnetized, the magnets outside the magnetization area may be magnetized in an unintended direction, and there is a concern that variations in the surface magnetic flux density may occur in each magnet.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for manufacturing a field magnet capable of properly magnetizing each magnet of the field magnet.

Means for Solving the Problems

[0006] The various embodiments disclosed in this specification employ different technical means to achieve their respective purposes. The purposes, features, and effects disclosed in this specification will become clearer by referring to the subsequent detailed description and the accompanying drawings.

[0007] Method 1 is, A method for manufacturing a field magneto having multiple magnets that form different magnetic poles in the circumferential direction, An assembly step in which the plurality of magnets before magnetization are assembled into a magnetization device in a ring-shaped arrangement, A first magnetization step involves generating a magnetizing magnetic field using the magnetization device and using that magnetic field to magnetize all of the magnets arranged in a ring shape, A second magnetization step is performed after the first magnetization step, in which the magnetization device generates a stronger magnetization magnetic field than in the first magnetization step, and uses this magnetization magnetic field to sequentially magnetize a predetermined number of magnets in the circumferential direction from all of the magnets arranged in a ring shape, It is characterized by having the following features.

[0008] In a field magnetization system having multiple magnets for each magnetic pole, the magnetization equipment can be simplified by dividing all the magnets into predetermined numbers and magnetizing them in batches. However, when magnetizing magnets in batches, there is a concern that variations in surface magnetic flux density may occur in each magnet due to leakage magnetic flux to magnets other than the target magnet.

[0009] In this manufacturing method, magnetization is performed in two stages. Specifically, in the first stage of magnetization, all magnets arranged in a ring are magnetized using a magnetizing magnetic field generated by a magnetizing device (first magnetization step). Then, in the second stage of magnetization, a stronger magnetizing magnetic field is generated by the magnetizing device than in the first stage, and this magnetic field is used to sequentially magnetize a predetermined number of magnets in the circumferential direction from all the magnets arranged in a ring (second magnetization step). In this case, in the first stage of magnetization, magnetization is performed all around with a relatively weak magnetizing magnetic field, and a counter-magnetic flux corresponding to the leakage magnetic flux is formed in each magnet. In the second stage of magnetization, a leakage magnetic flux is generated by the relatively strong magnetizing magnetic field, and there is concern that the surrounding magnets with the same pole as the magnetized magnet may be affected by the leakage magnetic flux. However, the counter-magnetic flux formed by the magnets in the first stage of magnetization suppresses the effect of the leakage magnetic flux. As a result, variations in surface magnetic flux density are suppressed in each magnet. As a result, each magnet in the field can be properly magnetized.

[0010] In method 2, in method 1, the first magnetization step is performed with a magnetic field weaker than the saturation magnetization magnetic field that saturates the magnet, and the second magnetization step is performed with the saturation magnetization magnetic field.

[0011] In the first magnetization process, magnetization is performed using a magnetic field weaker than the saturation magnetization field, and in the second magnetization process, magnetization is performed using the saturation magnetization field. This allows each magnet to be brought to the desired saturation magnetization state.

[0012] In method 3, in method 1 or 2, The magnetization device is, A magnetizing yoke is positioned opposite the field element, In the magnetization yoke, a plurality of magnetization coils are provided for each magnetic pole of the field, A power supply unit that supplies power to the plurality of magnetization coils, The system includes a switching unit that switches between a first state in which power for forming a magnetizing magnetic field is supplied from the power supply unit to all of the plurality of magnetizing coils, and a second state in which power for forming a magnetizing magnetic field is supplied from the power supply unit to some of the plurality of magnetizing coils. In the first magnetization step, the first state is established, and magnetization is performed on all of the magnets. In the second magnetization step, the second state is maintained, and magnetization is performed sequentially on the predetermined number of magnets.

[0013] In the first magnetization process, the system is set to a first state in which power is supplied from the power supply unit to all of the multiple magnetization coils, thereby magnetizing all the magnets. In the second magnetization process, the system is set to a second state in which power is supplied from the power supply unit to some of the magnetization coils, thereby magnetizing a predetermined number of magnets sequentially. In this case, the power supply unit distributes power to each magnetization coil, allowing for proper full-circumference magnetization of all magnets and segmented magnetization (magnetization of a predetermined number of magnets) using a stronger magnetic field than full-circumference magnetization.

[0014] In method 4, in method 3, The power supply unit includes a capacitor that supplies power for magnetization to the plurality of magnetization coils, and a charging unit that charges the capacitor. In the first magnetization step, the charging unit charges the capacitor, and the discharge of the capacitor simultaneously energizes all of the magnetization coils. In the second magnetization step, for each magnetization of a predetermined number of magnets, the charging unit charges the capacitor, and the discharge of the capacitor energizes the magnetization coil corresponding to the magnetization target at that time.

[0015] In full-circumference magnetization of all magnets, the discharge of the charged capacitor energizes all magnetization coils simultaneously. In contrast, in segmented magnetization of a predetermined number of magnets, the discharge of the charged capacitor energizes only some of the magnetization coils corresponding to each magnetization target (the predetermined number of magnets). This allows for the application of stronger magnetic fields in segmented magnetization compared to full-circumference magnetization. In other words, while using a common capacitor, it is possible to suitably apply low power to a relatively large number of magnetization coils and high power to a relatively small number of magnetization coils. Therefore, the capacitor capacity can be reduced compared to the case where high power is applied to all magnetization coils, and the magnetization equipment can be simplified.

[0016] In means 5, in means 3, the field element comprises the plurality of magnets and a cylindrical magnet holding member that holds each of the magnets, and in the assembly step, the plurality of magnets are assembled to the magnetization device while the circumferential position of the magnet holding member with respect to the magnetization yoke is restricted by a position regulating member.

[0017] By restricting the circumferential position of the magnet holding member relative to the magnetization yoke with a position regulating member, each magnet can be assembled to the correct position relative to the magnetization coil. This ensures that, when performing segmented magnetization, the magnet targeted for segmented magnetization is properly magnetized among all the magnets.

[0018] In means 6, in means 1, the magnet thickness dimension D1, which is the radial thickness of the magnet, and the circumferential width dimension D2 of one magnetic pole are such that D1 > D2 × 1 / 2.

[0019] In a configuration where the magnet thickness dimension D1, which is the radial thickness of the magnet, and the circumferential width dimension D2 of one magnetic pole satisfy D1 > D2×1 / 2, since the magnet thickness dimension D1 is relatively large, a strong magnetization magnetic field is required for magnetizing the magnet, and it is considered that strong leakage magnetic flux will occur. Also, since the circumferential width dimension D2 of one magnetic pole is relatively small, the pole pitch becomes short, and it is considered that the influence of the leakage magnetic flux becomes large. For example, in a rotating electrical machine with a large number of poles or high torque, the concern about the inconvenience caused by the leakage magnetic flux increases. In this regard, as described above, by performing the full-circumference magnetization and the segmented magnetization in two steps, suitable magnetization can be realized even for the field poles of a rotating electrical machine with a large number of poles or high torque.

[0020] In means 7, in means 1, the magnet is a radially anisotropic magnet.

[0021] When radial anisotropic orientation is performed in the magnet, the concern about the variation in the magnet magnetic flux density due to the leakage magnetic flux increases when performing the segmented magnetization. In this regard, as described above, by performing the full-circumference magnetization and the segmented magnetization in two steps, suitable magnetization can be realized even for the field poles using radially anisotropic magnets.

Brief Description of the Drawings

[0022] [Figure 1] Perspective view showing an overview of the rotor. [Figure 2] Cross-sectional view of the rotor. [Figure 3] Diagram showing the orientation direction of the magnet. [Figure 4] Diagram showing the rotor and the magnetizing device. [Figure 5] Diagram showing the state of the magnetic flux when performing segmented magnetization. [Figure 6] Diagram showing the angular distribution of the magnet surface magnetic flux density. [Figure 7] Circuit diagram showing the electrical configuration in the magnetizing device. [Figure 8] Flowchart showing the procedure of the magnetizing process. [Figure 9] Diagram showing the configuration of the position regulating member. [Figure 10](a) is a diagram to explain full-circumference magnetization, and (b) is a diagram to explain segmented magnetization. [Modes for carrying out the invention]

[0023] The embodiments will be described below with reference to the drawings. The rotating electric machine in this embodiment is used, for example, as an electric motor on a vehicle. However, the rotating electric machine can be widely used for industrial, marine, aircraft, home appliances, office automation equipment, amusement machines, and the like.

[0024] The rotating electric machine according to this embodiment is an outer rotor type surface magnet multiphase AC motor, and as is well known, it has a rotor as a field element and a stator as an armature. The rotor and stator are arranged to face each other radially, and the rotor is rotatable about the axis of rotation relative to the stator. Although not shown in the illustrations, the stator is a toothless stator, for example, in which the stator windings are assembled on the radially outer side of a cylindrical stator core (back yoke). However, the stator may also be a slot-wound stator in which the stator windings are wound around a plurality of slots provided in the stator core.

[0025] Figure 1 is a perspective view showing an overview of the rotor 10, and Figure 2 is a cross-sectional view of the rotor 10.

[0026] The rotor 10 comprises a substantially cylindrical rotor carrier 11 and an annular magnet unit 12 fixed to the rotor carrier 11. The rotor carrier 11 is made of, for example, a magnetic material and has a cylindrical portion 13 and an end plate portion 14 provided on one axial end of the cylindrical portion 13. The magnet unit 12 is fixed to the radially inner side of the cylindrical portion 13. The other axial end of the rotor carrier 11 is open. The rotor carrier 11 functions as a magnet holding member.

[0027] The magnet unit 12 is composed of a plurality of magnets 15 arranged along the circumferential direction of the rotor 10 such that their polarity alternates. As a result, the magnet unit 12 has multiple magnetic poles in the circumferential direction. The magnets 15 are, for example, sintered neodymium magnets having an intrinsic coercivity of 400 [kA / m] or more and a residual magnetic flux density Br of 1.0 [T] or more.

[0028] Each magnet 15 in the magnet unit 12 is a polarly anisotropic permanent magnet. As shown in Figure 3, the magnet 15 has different orientations of its easy magnetization axis on the d-axis side (the part closer to the d-axis), which is the magnetic pole center, and on the q-axis side (the part closer to the q-axis), which is the magnetic pole boundary. On the d-axis side, the easy magnetization axis is parallel to the d-axis, while on the q-axis side, the easy magnetization axis is perpendicular to the q-axis. In this case, an arc-shaped magnetic path is formed along the direction of the easy magnetization axis. In short, each magnet 15 is oriented such that on the d-axis side, which is the magnetic pole center, the easy magnetization axis is parallel to the d-axis compared to the q-axis side, which is the magnetic pole boundary.

[0029] The magnet unit 12 has two magnets 15 for each magnetic pole, and these magnets 15 are arranged so that their circumferential sides are in contact with each other. In the following description, the magnets 15 for one magnetic pole, that is, the two magnets 15 of the same pole arranged in the circumferential direction, will also be referred to as the magnetic pole magnets 16. However, the magnet unit 12 may also have a configuration in which there is one magnet 15 for each magnetic pole.

[0030] This embodiment is characterized by a method of manufacturing the magnet unit 12, which will be described below.

[0031] In the manufacturing of the magnet unit 12, first, refined raw materials such as neodymium, boron, and iron are melted and alloyed (melting process). Next, the alloy obtained in the melting process is pulverized into particles (pulverization process). Then, the powder obtained in the pulverization process is placed in a mold and pressure-molded in a magnetic field (molding process). Through this molding in the mold, the magnet 15 is formed into a predetermined shape. In this process, as described above, the magnetization easy axis of the magnet 15 is oriented, for example, in an arc shape.

[0032] After pressure molding, the molded product is sintered (sintering process), and after sintering is complete, it is heat-treated (heat treatment process). During the heat treatment, heating and cooling are performed several times. Then, machining such as grinding and surface treatment are performed (processing process). After that, the magnet is magnetized (magnetization process) to complete the magnet 15.

[0033] In the magnetization process, the magnet 15 is magnetized using a magnetization device 20, which is a manufacturing device. The magnetization device 20 and the magnetization process will be described in detail below. First, the magnetization device 20 will be described. Figure 4 shows the rotor 10 and the magnetization device 20 assembled to the rotor 10.

[0034] The magnetization device 20 is a device that magnetizes the magnets 15 of each magnetic pole using an electromagnet, and comprises a magnetization yoke 21 that is annular in shape and has a plurality of slots 22 on the radially inward side, and a plurality of magnetization coils 23 housed in each slot 22. In the magnetization yoke 21, the number of slots 22 is the same as the number of magnetic poles of the rotor 10 and is provided at the same pitch. The magnetization coils 23 are provided for each magnetic pole of the rotor 10 and are constructed by winding a conductor multiple times between adjacent slots 22 in the circumferential direction.

[0035] The rotor 10 is positioned radially outward from the magnetization yoke 21. At this time, the rotor 10 is positioned so that the magnetic pole center (d-axis) of the rotor 10 coincides with the circumferential center position of the slot 22 of the magnetization yoke 21. Then, when power is supplied by the power supply unit described later, current flows through each magnetization coil 23, generating a magnetization magnetic field for each magnetic pole of the rotor 10. This magnetization flux magnetizes each magnet 15, and magnetic poles of different polarities are formed alternately in the circumferential direction on the rotor 10.

[0036] Here, as a method for magnetizing each magnet 15 of the magnet unit 12, one can consider a method in which all the magnets 15 of the rotor 10 are divided into groups of multiple magnets 15 in the circumferential direction, and these groups of multiple magnets 15 are magnetized sequentially by the magnetization device 20. In terms of magnetic poles, this method is a method in which a predetermined number of magnetic poles (magnetic pole magnets 16) of all the magnetic poles (magnetic pole magnets 16) of the rotor 10 are magnetized sequentially by the magnetization device 20. In the following description, a distinction will be made between the case in which all the magnets 15 of the magnet unit 12 are magnetized simultaneously by the magnetization device 20, and the case in which the groups of multiple magnets 15 are magnetized sequentially by the magnetization device 20. The former will be called full-circumferential magnetization, and the latter will be called segmented magnetization.

[0037] Figure 5 shows the state when segmented magnetization is performed. In Figure 5, three pole magnets 16A, 16B, and 16C are shown, and the state in which magnetization is performed on two of the pole magnets, 16A and 16B. Note that in Figure 5, the magnetization device 20 is shown in a different form than in Figure 4, but the actual configuration is the same.

[0038] In Figure 5, the magnetization coils 23 for the south pole and north pole are energized respectively to magnetize the two magnetic pole magnets 16A and 16B. As a result, a magnetic flux acts on the magnetic pole magnets 16A and 16B, as shown by the arrows in the figure. In this case, in addition to the magnetic flux acting on the magnetic pole magnets 16A and 16B, which are the original targets for magnetization, a leakage flux Fa acts on the magnetic pole magnet 16C, which is not the target for magnetization. Due to the generation of the leakage flux Fa, variations occur in the surface magnetic flux density of the magnet 15 at each pole, as shown in Figure 6.

[0039] As shown in Figure 5, a configuration is conceivable in which the magnet thickness dimension D1, which is the radial thickness of the magnet 15, and the circumferential width dimension D2 of one magnetic pole (width dimension of the magnetic pole magnet 16) are equal, such that D1 > D2 × 1 / 2. Note that the width dimension D2 is, for example, the width dimension at the radial center position of the magnetic pole magnet 16, or the width dimension at the radial inner end of the magnetic pole magnet 16 or the radial inner end. In this configuration, because the magnet thickness dimension D1 is relatively large, a strong magnetization magnetic field is required when magnetizing the magnet 15, and it is conceivable that a strong leakage flux Fa will be generated. Also, because the circumferential width dimension D2 of one magnetic pole is relatively small, the magnetic pole pitch becomes shorter, and it is conceivable that the effect of the leakage flux Fa will be greater. For example, in rotating electric machines with a large number of poles or high torque, the concern about problems caused by the leakage flux Fa becomes greater.

[0040] In this embodiment, the rotor 10 is magnetized in two stages during manufacturing. Specifically, in the first stage of magnetization, all the magnets 15 arranged in a ring are magnetized by the magnetizing magnetic field generated by the magnetizing device 20 (first magnetization step). Then, in the second stage of magnetization, the magnetizing device 20 generates a stronger magnetizing magnetic field than in the first magnetization step, and uses this magnetic field to sequentially magnetize a predetermined number of magnets 15 in the circumferential direction from all the magnets 15 arranged in a ring (second magnetization step). The details are described below.

[0041] Figure 7 is a circuit diagram showing the electrical configuration of the magnetization device 20. As shown in Figure 7, the magnetization device 20 comprises an AC power supply 31, a charging circuit 32, a boost circuit 33, a rectifier circuit 34, a capacitor 35, a first switch 36, a plurality of second switches 37, and a control device 40.

[0042] An AC power supply 31 is connected to a boost circuit 33 via a charging circuit 32. The charging circuit 32 switches between a state where AC power is output from the AC power supply 31 to the boost circuit 33 and a state where it is not. Note that the AC power supply 31 may be an external power supply. A rectifier circuit 34 is connected to the boost circuit 33. The boost circuit 33 increases the voltage of the AC power supplied from the AC power supply 31 and outputs it to the rectifier circuit 34. A capacitor 35 is connected to the rectifier circuit 34. The rectifier circuit 34 converts the AC power input from the boost circuit 33 into DC and charges the capacitor 35. The capacitor 35 is charged to a voltage of, for example, several thousand volts.

[0043] Multiple magnetizing coils 23 are connected in series, and a capacitor 35 is connected in parallel to these multiple magnetizing coils 23. Each magnetizing coil 23 is energized by the discharge of the capacitor 35. A first switch 36 is provided in the electrical path between the capacitor 35 and the magnetizing coils 23 to switch between energizing and disconnecting the electrical path. In addition, short-circuit paths are provided at both ends of each magnetizing coil 23, and a second switch 37 is provided at each of these short-circuit paths.

[0044] In this embodiment, the capacitor 35 corresponds to a power supply unit that supplies power to each magnetization coil 23. The AC power supply 31, charging circuit 32, boost circuit 33, and rectifier circuit 34 correspond to a charging unit that charges the capacitor 35.

[0045] The control device 40 operates the charging circuit 32 to switch between a state where AC power is output from the AC power supply 31 to the boost circuit 33 and a state where it is not output. In this case, the capacitor 35 is charged when AC power is output from the AC power supply 31 to the boost circuit 33. The control device 40 also controls the on / off state of each switch 36, 37. In this case, when the first switch 36 is turned on and at least one of the second switches 37 is kept in the off state, current is supplied from the capacitor 35 to the predetermined magnetization coil 23.

[0046] In this embodiment, when magnetizing the magnet unit 12, it is possible to perform full-circumference magnetization, in which all magnetization coils 23 are energized and all magnets 15 are magnetized simultaneously, and segmented magnetization, in which some of the magnetization coils 23 are energized and multiple magnets 15 are magnetized in sequence. The on / off state of each switch 36, 37 is controlled according to which type of magnetization is performed.

[0047] In this case, when performing full-circumference magnetization, the control device 40 turns on the first switch 36 and turns off all the second switches 37. As a result, current is supplied to all the magnetization coils 23 (corresponding to the first state).

[0048] On the other hand, when performing segmented magnetization, the control device 40 turns on the first switch 36 and turns on only some of the second switches 37 out of all of them. This energizes some of the magnetization coils 23 out of all of them (corresponding to the second state). Specifically, for example, to energize only the magnetization coil 23A out of all the magnetization coils 23 in Figure 7, the first switch 36 is turned on, and only the second switch 37 corresponding to the magnetization coil 23A is turned off, while all the other second switches 37 are turned on. This energizes only the magnetization coil 23A. The control device 40 corresponds to a switching unit that switches between the first state and the second state.

[0049] In this embodiment, all magnetization coils 23 are divided into pairs of adjacent coils 23 in the circumferential direction, and these pairs are magnetized sequentially. In the configuration shown in Figure 7, a second switch 37 may be provided for each pair of magnetization coils 23. In divided magnetization, the number of magnetization coils 23 that are magnetized in one pass is at least one, and preferably half of the total number.

[0050] In this case, when full-circumference magnetization is performed, the charging power of the capacitor 35 is supplied to all magnetization coils 23, whereas when segmented magnetization is performed, the charging power of the capacitor 35 is supplied to only a specific magnetization coil 23 out of all the magnetization coils 23. Therefore, when full-circumference magnetization is performed, the applied voltage to each magnetization coil 23 is relatively low, and each magnet 15 is magnetized with a relatively weak magnetic field. In contrast, when segmented magnetization is performed, the applied voltage to each magnetization coil 23 is relatively high, and each magnet 15 is magnetized with a relatively strong magnetic field.

[0051] The following describes a series of magnetization processes, including full-circumference magnetization and segmented magnetization. Figure 8 is a flowchart showing the detailed steps in the magnetization process.

[0052] When magnetizing each magnet 15, the rotor 10, in which the magnets 15 are not yet magnetized, is first assembled into the magnetization device 20 (step S11). This ensures that the magnets 15, before magnetization, are assembled into the magnetization device 20 in a ring-shaped arrangement. As mentioned above, each magnet 15 has its easy magnetization axis already oriented. At this time, each magnet 15 is positioned so that its q-axis faces the slot 22. Step S11 corresponds to the assembly process.

[0053] In this assembly process, it is preferable that each magnet 15 is assembled to the magnetization device 20 while the circumferential position of the rotor carrier 11 relative to the magnetization yoke 21 is restricted. Figure 9 shows a specific configuration for restricting the position of the rotor carrier 11. Figure 9(a) is a cross-sectional view of the rotor 10 and the magnetization device 20, and Figure 9(b) is a cross-sectional view taken along line 9B-9B in Figure 9(a).

[0054] As shown in Figures 9(a) and (b), the magnetization yoke 21 is positioned on the opposite side (radially inward) of the rotor carrier 11 relative to the magnets 15 of the rotor 10, and in this state, the axial end of the magnetization yoke 21 and the end plate portion 14 of the rotor carrier 11 face each other. The magnetization yoke 21 is also provided with a columnar engaging portion 25 that extends in the axial direction, and the circumferential position of the rotor carrier 11 relative to the magnetization yoke 21 is restricted by inserting this engaging portion 25 into a positioning hole 14a provided in the end plate portion 14 of the rotor carrier 11. The engaging portion 25 corresponds to a position restricting member.

[0055] Next, as the first stage of magnetization, the rotor 10 is magnetized all around (step S12). Figure 10(a) is a diagram illustrating all-around magnetization. As shown in Figure 10(a), in all-around magnetization, a weak magnetizing magnetic field is generated by weakly energizing all the magnetizing coils 23 of the magnetization device 20, and this magnetizing magnetic field magnetizes all the magnets 15 arranged in a ring. Step S12 corresponds to the first magnetization process. In this all-around magnetization, the capacitor 35 is charged in accordance with the output of AC power from the AC power supply 31, and the discharge of the capacitor 35 energizes all the magnetizing coils 23 at the same time. As a result, all-around magnetization is performed with a relatively weak magnetizing magnetic field. At this time, magnetization is performed with a magnetic field weaker than the saturation magnetizing magnetic field that saturates the magnets 15.

[0056] Subsequently, as the second stage of magnetization, the rotor 10 is magnetized in sections (step S13). Figure 10(b) is a diagram illustrating section magnetization. As shown in Figure 10(b), in section magnetization, the two-pole magnets 16A and 16B are magnetized at one time, and a strong magnetization magnetic field is generated by applying a strong current to the two magnetization coils 23 to magnetize each of the pole magnets 16A and 16B. In addition, for all the magnets 15 (pole magnets 16) arranged in a ring, a predetermined number of magnets 15 are magnetized in sequence. Step S13 corresponds to the second magnetization process.

[0057] In this case, each time the two magnetic poles are magnetized separately, the capacitor 35 is charged in accordance with the output of AC power from the AC power source 31, and the discharge of the capacitor 35 energizes the two magnetization coils 23 corresponding to the two magnetic poles of the magnet 15. As a result, the separate magnetization is carried out with a relatively strong magnetization magnetic field. At this time, magnetization is carried out with a saturation magnetization magnetic field. The saturation magnetization magnetic field is defined as the magnetic field that magnetizes the magnet 15 to 100% magnetization rate.

[0058] In the segmented magnetization shown in Figure 10(b), even if leakage flux Fa is generated due to the formation of a relatively strong magnetization magnetic field, the effect of leakage flux Fa is suppressed by the counter-magnetic flux Fb of each magnet 15 formed in the previous full-circumference magnetization. In this case, for example, the decrease in surface magnetic flux density due to leakage flux Fa is suppressed in the same-pole magnet 16C that is closest to the south-pole magnet 16A in the circumferential direction. In other words, the only place where the generation of leakage flux Fa becomes a problem is at least the same-pole magnet 15 that is one position away in the circumferential direction, and the problem of leakage flux Fa for that same-pole magnet 15 is resolved. As a result, the variation in surface magnetic flux density in each magnet 15 is suppressed. According to the inventors, it has been confirmed that the variation in surface magnetic flux density can be kept within 25%.

[0059] Furthermore, after the two-stage magnetization is complete, the rotor 10 is removed from the magnetization device 20 (step S14). This completes the series of magnetization processes.

[0060] According to the embodiment described in detail above, the following excellent effects can be obtained.

[0061] By performing both full-circumference magnetization and segmented magnetization as described above when magnetizing the magnets 15 of the rotor 10, variations in surface magnetic flux density are suppressed in each magnet 15. As a result, each magnet 15 of the rotor 10 can be properly magnetized. Furthermore, by suppressing variations in surface magnetic flux density in each magnet 15, high torque output in the rotating electric machine is possible, and vibrations and noise caused by variations in surface magnetic flux density can be suppressed.

[0062] In the full-circumference magnetization (first magnetization step), magnetization is performed using a magnetic field weaker than the saturation magnetization magnetic field, while in the segmented magnetization (second magnetization step), magnetization is performed using the saturation magnetization magnetic field. This makes it possible to achieve the desired saturation magnetization state for each magnet 15.

[0063] In full-circumference magnetization, the first state is achieved by supplying power from the power supply unit to all magnetizing coils 23 of the magnetizing device 20, thereby magnetizing all magnets 15. In contrast, in segmented magnetization, the second state is achieved by supplying power from the power supply unit to only some of the magnetizing coils 23, thereby sequentially magnetizing a predetermined number of magnets 15 at a time. In this case, the power supply unit distributes power to each magnetizing coil 23, allowing for proper full-circumference magnetization of all magnets 15 and segmented magnetization (magnetization of a predetermined number of magnets 15 at a time) using a stronger magnetic field than full-circumference magnetization.

[0064] In full-circumference magnetization of all magnets 15, the discharge of the charged capacitor 35 energizes all magnetization coils 23 simultaneously. In contrast, in segmented magnetization of a predetermined number of magnets 15, the discharge of the charged capacitor 35 energizes only some of the magnetization coils 23 corresponding to each magnetization target (a predetermined number of magnets 15). This allows for more favorable implementation of stronger magnetic field magnetization in segmented magnetization than in full-circumference magnetization. In other words, while using a common capacitor 35, it is possible to suitably apply low power to a relatively large number of magnetization coils 23 and high power to a relatively small number of magnetization coils 23. Therefore, the capacitor capacity can be reduced compared to the case where high power is applied to all magnetization coils 23, and the magnetization equipment can be simplified.

[0065] The circumferential position of the rotor carrier 11 relative to the magnetization yoke 21 is restricted by the engagement portion 25, which acts as a position-regulating member, allowing each magnet 15 to be assembled to the magnetization coil 23 in the correct position. As a result, when performing segmented magnetization, the magnet 15 that is the target of segmented magnetization among all the magnets 15 can be properly magnetized.

[0066] In a configuration where the radial thickness dimension D1 of the magnet 15 and the circumferential width dimension D2 of one magnetic pole are equal, D1 > D2 × 1 / 2, the influence of leakage flux Fa is likely to be significant. For example, in rotating electric machines with a large number of poles or high torque, concerns about problems caused by leakage flux Fa become greater. In this regard, by performing full-circumferential magnetization and segmented magnetization in two stages as described above, suitable magnetization can be achieved even for the rotor 10 of a rotating electric machine with a large number of poles or high torque.

[0067] When the magnet 15 is polarly anisotropically oriented, there is a greater concern about variations in magnetic flux density due to leakage flux Fa when performing segmented magnetization. In this regard, as described above, by performing full-circumference magnetization and segmented magnetization in two stages, suitable magnetization can be achieved even with a rotor 10 using polarly anisotropically oriented magnets.

[0068] (modified version) In the above embodiment, the configuration for magnetizing two magnetic poles of magnet 15 was used in the divided magnetization process. However, this can be changed to a configuration in which one magnetic pole of magnet 15 is magnetized, or a configuration in which three or more magnetic poles of magnet 15 are magnetized simultaneously.

[0069] In the above embodiment, the magnet unit 12 is configured such that the magnet 15 is divided for at least one magnetic pole, but this can be changed to a configuration where one magnet is provided for multiple magnetic poles, or a configuration using a single annular magnet. Furthermore, the magnet 15 is not limited to having an arc-shaped magnetic path, but may also have a linear magnetic path extending in the radial direction.

[0070] In the embodiments described above, a surface-mounted magnet type rotor was used as the rotor 10, but instead, a configuration using an embedded magnet type rotor may also be used.

[0071] In the embodiments described above, the rotating electric machine is of an outer rotor structure, but this may be changed to a rotating electric machine of an inner rotor structure. In a rotating electric machine of an inner rotor structure, the stator is provided on the radially outer side, and the rotor is provided on the radially inner side.

[0072] As a rotating electric machine, it is also possible to use a rotating armature type rotating electric machine, in which the armature is the rotor and the field is the stator, instead of a rotating field type rotating electric machine, in which the armature is the rotor and the field is the stator.

[0073] The disclosures in this specification are not limited to the exemplary embodiments. The disclosures encompass the exemplary embodiments and variations thereof by those skilled in the art. For example, the disclosures are not limited to combinations of parts and / or elements shown in the embodiments. The disclosures are implementable in a variety of combinations. The disclosures may have additional parts that can be added to the embodiments. The disclosures encompass embodiments in which parts and / or elements are omitted. The disclosures encompass substitutions or combinations of parts and / or elements between one embodiment and another. The scope of the disclosed technical areas is not limited to the descriptions of the embodiments. Some of the scope of the disclosed technical areas are indicated by the claims and should be understood to include all modifications within the meaning and scope equivalent to the claims.

[0074] The technical concepts extracted from the above-described embodiments are described below. [Configuration 1] A method for manufacturing a field magnet (10) having a plurality of magnets (15) that form different magnetic poles in the circumferential direction, The assembly process involves assembling the plurality of magnets, before magnetization, into the magnetization device (20) in a ring-shaped arrangement, A first magnetization step involves generating a magnetizing magnetic field using the magnetization device and using that magnetic field to magnetize all of the magnets arranged in a ring shape, A second magnetization step is performed after the first magnetization step, in which the magnetization device generates a stronger magnetization magnetic field than in the first magnetization step, and uses this magnetization magnetic field to sequentially magnetize a predetermined number of magnets in the circumferential direction from all of the magnets arranged in a ring shape, A method for manufacturing a field magneto having the following characteristics. [Configuration 2] In the first magnetization step, magnetization is performed using a magnetic field weaker than the saturation magnetization magnetic field used to saturate the magnet. The method for manufacturing a field magnet according to configuration 1, wherein the second magnetization step is performed using the saturated magnetization magnetic field. [Configuration 3] The magnetization device is, A magnetizing yoke (21) is positioned opposite to the field element, In the magnetization yoke, a plurality of magnetization coils (23) are provided for each magnetic pole of the field magneto, A power supply unit (35) that supplies power to the plurality of magnetization coils, The system includes a switching unit (40) that switches between a first state in which power for forming a magnetizing magnetic field is supplied from the power supply unit to all of the plurality of magnetizing coils, and a second state in which power for forming a magnetizing magnetic field is supplied from the power supply unit to some of the plurality of magnetizing coils. In the first magnetization step, the first state is established, and magnetization is performed on all of the magnets. The method for manufacturing a field magnet according to configuration 1 or 2, wherein the second magnetization step is performed in the second state and magnetization is carried out sequentially on a predetermined number of magnets. [Structure 4] The power supply unit includes a capacitor (35) that supplies power for magnetization to the plurality of magnetization coils, and a charging unit (31-34) that charges the capacitor. In the first magnetization step, the charging unit charges the capacitor, and the discharge of the capacitor simultaneously energizes all of the magnetization coils. The method for manufacturing a field magnet according to configuration 3, wherein in the second magnetization step, the charging unit charges the capacitor each time a predetermined number of magnets are magnetized, and the discharge of the capacitor energizes the magnetization coil corresponding to the magnetization target at that time. [Composition 5] The field element comprises the plurality of magnets and a cylindrical magnet holding member (11) that holds each of the magnets. The method for manufacturing a field magnet according to configuration 3 or 4, wherein in the assembly step, the plurality of magnets are assembled to the magnetization device while the circumferential position of the magnet holding member with respect to the magnetization yoke is restricted by a position restricting member (25). [Composition 6] A method for manufacturing a field magnet according to any one of configurations 1 to 5, wherein the magnet thickness dimension D1, which is the radial thickness of the magnet, and the circumferential width dimension D2 of one magnetic pole are such that D1 > D2. [Composition 7] The method for manufacturing a field magnet according to any one of configurations 1 to 6, wherein the magnet is a polar anisotropic magnet. [Explanation of symbols]

[0075] 10...Rotor, 15...Magnet, 20...Magnetic device.

Claims

1. A method for manufacturing a field magnet (10) having a plurality of magnets (15) that form different magnetic poles in the circumferential direction, The assembly process involves assembling the plurality of magnets, before magnetization, into the magnetization device (20) in a ring-shaped arrangement, A first magnetization step involves generating a magnetizing magnetic field using the magnetization device and using that magnetic field to magnetize all of the magnets arranged in a ring shape, A second magnetization step is performed after the first magnetization step, in which the magnetization device generates a stronger magnetization magnetic field than that of the first magnetization step, and uses that magnetization magnetic field to sequentially magnetize a predetermined number of magnets in the circumferential direction from all of the magnets arranged in a ring shape, It has, The magnetization device is, A magnetizing yoke (21) is positioned opposite to the field element, In the magnetization yoke, a plurality of magnetization coils (23) are provided for each magnetic pole of the field magneto, A capacitor (35) that supplies power for magnetization to the plurality of magnetization coils, A charging unit (31-34) that charges the capacitor, The system includes a switching unit (40) that switches between a first state in which power for forming a magnetized magnetic field is supplied from the capacitor to all of the plurality of magnetized coils, and a second state in which power for forming a magnetized magnetic field is supplied from the capacitor to some of the plurality of magnetized coils. In the first magnetization step, the charging unit charges the capacitor and brings it to the first state, and by discharging the capacitor, current is supplied to all the magnetization coils at the same time to magnetize all the magnets. A method for manufacturing a field magnet, wherein in the second magnetization step, the capacitor is charged by the charging unit each time a predetermined number of magnets are magnetized, bringing the system to the second state, and current is supplied to the magnetization coil corresponding to the magnetization target each time by discharging the capacitor, thereby sequentially magnetizing the predetermined number of magnets.

2. In the first magnetization step, magnetization is performed using a magnetic field weaker than the saturation magnetization magnetic field used to saturate the magnet. The method for manufacturing a field magnet according to claim 1, wherein the second magnetization step is performed using the saturated magnetization magnetic field.

3. The field element comprises the plurality of magnets and a cylindrical magnet holding member (11) that holds each of the magnets. The method for manufacturing a field magnet according to claim 1 or 2, wherein in the assembly step, the plurality of magnets are assembled to the magnetization device while the circumferential position of the magnet holding member with respect to the magnetization yoke is restricted by a position restricting member (25).

4. The method for manufacturing a field magnet according to claim 1 or 2, wherein the magnet thickness dimension D1, which is the radial thickness of the magnet, and the circumferential width dimension D2 of one magnetic pole are D1 > D2 × 1 / 2.

5. The method for manufacturing a field magnet according to claim 1 or 2, wherein the magnet is a polarly anisotropic magnet.

Images