Rotor manufacturing apparatus, rotor manufacturing method, and rotor

Abstract

To provide a rotor manufacturing apparatus and a rotor manufacturing method capable of magnetizing a permanent magnet embedded in a rotor core with a high magnetic force.SOLUTION: Respective opposed protrusion portions 32b and 42b of an apparatus upper side portion 31 and an apparatus lower side portion 41 opposed to a rotor 20 in an axial direction are excited to the same polarity by the energization of magnetizing coils 33a and 43a in the same magnetizing of the permanent magnet 23 when a permanent magnet 23 embedded in the rotor 20 is magnetized from the outside by using a magnetization device 30. A magnetization flux of the same polarity passes through an outer core portion 25 of a rotor core 22 located inside a folded shape of the permanent magnet 23 and outside in a radial direction of the permanent magnet 23 from both sides in the axial direction, whereby the permanent magnet 23 is magnetized.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an apparatus for manufacturing an embedded permanent magnet rotor in which embedded permanent magnets are magnetized from outside the rotor, a method for manufacturing a rotor, and the rotor. [Background technology]

[0002] Rotating electric machines using interior permanent magnet (IPM) rotors are well known. Interior permanent magnet rotors have permanent magnets embedded in the rotor core, and are configured to generate magnetic torque from the permanent magnets, as well as reluctance torque from an outer core portion located radially outward of the permanent magnets. Some interior permanent magnet rotors have a rotor core with embedded, unmagnetized permanent magnets that is magnetized from the outer diameter side by a magnetizing device (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-193587 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, one measure to improve the performance of an embedded magnet rotor is to fold the permanent magnets into an approximately V- or U-shaped configuration, thereby expanding the magnetic surface of the permanent magnet and the outer core portion of the rotor core, thereby increasing both the magnet torque and reluctance torque.

[0005] However, if the bent portion of the permanent magnet is positioned further radially inward to form a deeper fold in order to increase the distance between the magnet surface of the permanent magnet and the outer core portion of the rotor core, the permanent magnet, particularly the bent portion and the vicinity of the bent portion, will be farther away from the magnetizing device. Therefore, with the method of magnetizing the rotor core from the outer diameter side as disclosed in Patent Document 1 and the like, there is a concern as to whether the bent portion and the vicinity of the bent portion of the permanent magnet, which are farther away from the magnetizing device, will be magnetized with sufficient magnetic force.

[0006] The present invention has been made to solve the above-mentioned problems, and its object is to provide a rotor manufacturing apparatus and method that can magnetize permanent magnets embedded in a rotor core with high magnetic force, and a rotor that has been magnetized in this manner. [Means for solving the problem]

[0007] A rotor manufacturing apparatus for solving the above-mentioned problems is a rotor manufacturing apparatus for a rotor (20) having permanent magnets (23) embedded in magnet accommodating holes (24) of a rotor core (22) and having a folded shape that is convex on the radially inward side, the rotor manufacturing apparatus including a magnetizing device (30) that magnetizes the embedded permanent magnets from the outside of the rotor, the magnetizing device including a first magnetizing section (31) disposed on one axial side of the rotor and having magnetizing coils (33a, 35a1, 35a2) that supply a magnetizing flux to the permanent magnet, and a second magnetizing section (41) disposed on the other axial side of the rotor and having magnetizing coils (43a, 45a1, 45a2) that supply a magnetizing flux to the permanent magnet, the first and second magnetizing sections having opposing convex sections (32b, 42b) on which the magnetizing coils are wound and for supplying the magnetizing flux, The portion of the rotor core that is inside the folded shape and located radially outside the permanent magnet is the outer core portion (25), and the opposing convex portion is configured with a peripheral shape such that, when viewed in the axial direction of the rotor, the outer peripheral surface of the opposing convex portion matches the magnet surface inside the folded shape of the permanent magnet and the outer peripheral surface of the outer core portion in the radial direction, or the opposing convex portion is configured to be smaller than the outer core portion when viewed in the axial direction of the rotor, and when the permanent magnet is magnetized by passing current through the magnetizing coil, the first and second magnetized portions that face each other in the axial direction of the rotor are excited to the same polarity, and the permanent magnet is magnetized in the thickness direction of the permanent magnet when viewed in the axial direction of the rotor by passing magnetizing flux of the same polarity through both axial sides of the outer core portion (25) of the rotor core that is located inside the folded shape of the permanent magnet.

[0008] A method for manufacturing a rotor that solves the above-described problems is a method for manufacturing a rotor (20) having a permanent magnet (23) that is embedded in a magnet accommodating hole (24) of a rotor core (22) and has a folded shape that is convex on the radially inward side, and the method uses a magnetizing device (30) to magnetize the embedded permanent magnet from the outside of the rotor, the magnetizing device including a first magnetizing portion (31) that is arranged on one axial side of the rotor and has magnetizing coils (33a, 35a1, 35a2) that supply a magnetizing flux to the permanent magnet, and a second magnetizing portion (41) that is arranged on the other axial side of the rotor and has magnetizing coils (43a, 45a1, 45a2) that supply a magnetizing flux to the permanent magnet, and the first and second magnetizing portions have opposing convex portions (32b, 42b) around which the magnetizing coils are wound and for supplying the magnetizing flux. The portion of the rotor core that is inside the folded shape of the permanent magnet and located radially outside the permanent magnet is an outer core portion (25), and the opposing convex portion is configured with a peripheral shape such that, when viewed in the axial direction of the rotor, the outer peripheral surface of the opposing convex portion matches the magnet surface inside the folded shape of the permanent magnet and the outer peripheral surface of the outer core portion in the radial direction, or the opposing convex portion is configured to be smaller than the outer core portion when viewed in the axial direction of the rotor, and when the permanent magnet is magnetized by passing current through the magnetizing coil, the first and second magnetized portions that face each other in the axial direction of the rotor are magnetized with the same polarity, and the permanent magnet is magnetized in the thickness direction of the permanent magnet when viewed in the axial direction of the rotor by passing magnetizing flux of the same polarity from both axial sides of the outer core portion (25) of the rotor core that is located inside the folded shape of the permanent magnet.

[0009] According to the rotor manufacturing apparatus and rotor manufacturing method, when magnetizing the permanent magnets embedded in the rotor, the first and second magnetized portions that face each other in the axial direction of the rotor are excited to the same polarity, and magnetization is performed by passing magnetizing flux of the same polarity through the rotor core portion located inside the folded shape of the permanent magnet from both axial sides. This makes it possible to supply a magnetizing flux suitable for magnetization to the entire folded shape of the permanent magnet, from the radially outer end to the bent portion closer to the radially inner side, and therefore makes it possible to magnetize the entire permanent magnet with more effective and sufficient magnetic force.

[0010] The rotor magnetized using the rotor manufacturing method that solves the above-mentioned problems has a permanent magnet (23) that is embedded in a magnet accommodating hole (24) of a rotor core (22) and has a folded shape that is convex radially inward, and is configured by magnetizing the embedded permanent magnet from the outside using a magnetizing device (30), and the magnetization unit of the permanent magnet that is magnetized by passing magnetizing flux of the same polarity through both axial sides of the outer core portion (25) of the rotor core located inside the folded shape of the permanent magnet is defined as a block, and the rotor is configured by stacking multiple blocks in the axial direction.

[0011] When magnetizing permanent magnets by supplying magnetizing magnetic flux from the axial direction of the rotor, there is a concern as to whether the permanent magnets located in the middle part of the axial direction can be sufficiently magnetized. However, the rotor described above is configured by stacking multiple magnetization blocks in the axial direction, each block being a magnetization unit that allows sufficient magnetization, so that even rotors that are long in the axial direction can be provided with permanent magnets with sufficient magnetic force. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram illustrating the configuration of a rotating electric machine having an embedded magnet rotor. [Figure 2] FIG. [Figure 3] Cross-sectional view of a rotor. [Figure 4] FIG. 1 is an explanatory diagram illustrating an overall configuration of a magnetizing device according to an embodiment. [Figure 5]FIG. 2 is an explanatory diagram for explaining the overall configuration of the magnetizing device of the same embodiment. [Figure 6] 4A and 4B are explanatory diagrams illustrating the configuration of a coil body of a magnetizing device. [Figure 7] FIG. 2 is an explanatory diagram illustrating a permanent magnet magnetized by the magnetizing device of the same embodiment. [Figure 8] FIG. 10 is an explanatory diagram for explaining the overall configuration of a magnetizing device according to a modified example. [Figure 9] FIG. 10 is an explanatory diagram illustrating the configuration of a coil body of a magnetizing device according to a modified example. [Figure 10] FIG. 10 is a cross-sectional view of a rotor according to a modified example including permanent magnets magnetized by a magnetizing device. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of a rotor manufacturing apparatus, a rotor manufacturing method, and a rotor will be described below. 1, the rotating electric machine M of this embodiment is configured as an embedded magnet brushless motor. The rotating electric machine M includes a substantially annular stator 10 and a substantially cylindrical rotor 20 rotatably disposed in the radially inner space of the stator 10.

[0014] The stator 10 includes a substantially annular stator core 11. The stator core 11 is made of a magnetic metal material, for example, by stacking multiple electromagnetic steel sheets in the axial direction. The stator core 11 has twelve teeth 12, which extend radially inward and are equally spaced circumferentially in this embodiment. Each tooth 12 has the same shape. The radially inner ends of the teeth 12 are substantially T-shaped, and the tip surfaces 12a are arc-shaped following the outer circumferential surface of the rotor 20. Windings 13 are wound around the teeth 12 in a concentrated winding manner. The windings 13 are connected in a three-phase configuration and function as U, V, and W phases, respectively, as shown in FIG. 1 . When power is supplied to the windings 13, a rotating magnetic field is generated in the stator 10 to rotate the rotor 20. In this stator 10, the outer circumferential surface of the stator core 11 is fixed to the inner circumferential surface of the housing 14.

[0015] The rotor 20 includes a rotating shaft 21, a substantially cylindrical rotor core 22 into whose center the rotating shaft 21 is fitted, and eight permanent magnets 23 in this embodiment embedded inside the rotor core 22. The rotor core 22 is made of a magnetic metal material, for example, made by laminating multiple electromagnetic steel plates in the axial direction. The rotor 20 is rotatably disposed relative to the stator 10 with the rotating shaft 21 supported by a bearing (not shown) provided in the housing 14.

[0016] The rotor core 22 has magnet accommodating holes 24 for accommodating the permanent magnets 23. In this embodiment, eight magnet accommodating holes 24 are provided at equal intervals around the circumferential direction of the rotor core 22. Each magnet accommodating hole 24 has a generally V-shaped folded shape that protrudes radially inward, and the magnet accommodating holes 24 are identical to each other. The magnet accommodating holes 24 are provided over the entire axial direction of the rotor core 22.

[0017] Here, the permanent magnet 23 of this embodiment is a bonded magnet made by molding and solidifying a magnetic material made by mixing magnetic powder with resin. That is, the permanent magnet 23 is formed by using the magnet accommodating hole 24 of the rotor core 22 as a molding die, filling the magnet accommodating hole 24 with unsolidified magnetic material by injection molding without gaps, and then solidifying it inside the magnet accommodating hole 24 after filling. Therefore, the hole shape of the magnet accommodating hole 24 becomes the outer shape of the permanent magnet 23. The magnetic powder used for the permanent magnet 23 of this embodiment is, for example, a samarium iron nitrogen (SmFeN) magnet, but other rare earth magnets, etc. may also be used.

[0018] Each permanent magnet 23 has a generally V-shaped folded shape that protrudes radially inward. Specifically, as shown in FIG. 2, each permanent magnet 23 has a shape in which radially inner ends of a pair of straight portions 23a are connected by a bent portion 23b. A radially outer end 23c of each straight portion 23a is located near the outer peripheral surface 22a of the rotor core 22. The thickness Wm of each permanent magnet 23 is constant along the entire V-shaped path including the pair of straight portions 23a and the bent portion 23b. Each permanent magnet 23 is symmetrical with respect to its own circumferential center line Ls that passes through the axial center O1 of the rotor 20, and is adjacent to a magnetic pole boundary line Ld between adjacent permanent magnets 23 that passes through the axial center O1 of the rotor 20. The angle between adjacent magnetic pole boundaries Ld, i.e., the magnetic pole opening angle θm of the rotor magnetic pole portion 26 including each permanent magnet 23, is 180° in electrical angle.

[0019] Here, let the magnetic pole pitch Lp be the distance between the intersection of the extension of the inner surface of each straight portion 23a of the V-shaped permanent magnet 23 and the outer peripheral surface 22a of the rotor core 22, and let the embedment depth Lm be the distance from the outer peripheral surface 22a of the rotor core 22 to the inner surface of the bent portion 23b on the circumferential center line Ls of the permanent magnet 23. As an example, the permanent magnet 23 of this embodiment is configured to have a deep folded shape such that the embedment depth Lm is greater than the magnetic pole pitch Lp. In other words, the magnet surface 23x of the permanent magnet 23 of this embodiment, formed by the inner surfaces of each straight portion 23a and bent portion 23b, is configured to be larger than the magnet surface of a well-known surface magnet (not shown). Note that this folded shape of the permanent magnet 23 is just one example, and it can be appropriately modified, such as a shallower embedment depth Lm or a roughly U-shaped folded shape with larger bent portions 23b.

[0020] 2 and 3, the permanent magnets 23 are embedded to a large depth Lm, so that the bent portions 23b are positioned radially inward and closer to the shaft insertion hole 22b in the center of the rotor core 22, into which the rotating shaft 21 is inserted. The permanent magnets 23 are provided over the entire axial direction of the rotor core 22. The rotor 20 of this embodiment has a short axial length L1, and the permanent magnets 23 incorporated in the rotor 20 have a rectangular shape that is long in the radial direction of the rotor 20 when viewed from the side.

[0021] The permanent magnets 23 solidified in the magnet accommodating holes 24 of the rotor core 22 are magnetized from the outside of the rotor core 22 using a magnetizing device 30 shown in FIG. 4 etc., so that the unmagnetized state functions as an original magnet. Details of the magnetizing device 30 and the magnetizing method using the magnetizing device 30 will be described later. In this embodiment, eight permanent magnets 23 are provided in the circumferential direction of the rotor core 22, and are magnetized so that the polarities are alternately different in the circumferential direction. Furthermore, each of the permanent magnets 23 is magnetized in its own thickness direction.

[0022] A portion of the rotor core 22 located inside the V-shaped folded shape of the permanent magnets 23 and radially outward of the permanent magnets 23 functions as an outer core portion 25 that faces the stator 10 and generates reluctance torque. The outer core portion 25 has a generally triangular shape with one vertex facing toward the center of the rotor 20 when viewed in the axial direction. In this embodiment, the rotor 20 includes the permanent magnets 23 and the outer core portion 25 surrounded by the inside of the V-shape of the permanent magnets 23, and is configured as eight rotor pole portions 26. Each rotor pole portion 26 functions as a north pole and a south pole alternately in the circumferential direction, as shown in FIG. 1 . A rotor 20 having such rotor pole portions 26 can suitably generate magnet torque and reluctance torque.

[0023] Next, a manufacturing apparatus and method for the rotor 20 including a magnetizing device 30 for the permanent magnets 23 and a magnetizing method for the permanent magnets 23 using the magnetizing device 30 will be described. [Magnetization device configuration] The magnetizing device 30 of this embodiment will be described with reference to Fig. 4 and Fig. 5. Note that hatching has been omitted from cross-sectional areas in Fig. 4 and Fig. 5, as appropriate. Also, the magnetizing coil 33a of the coil body 33 and the like are shown in a simplified form.

[0024] 4 and 5, the magnetizing device 30 includes an upper device part 31 and a lower device part 41, and is configured so that the upper device part 31 and the lower device part 41 can be moved toward and away from each other so as to enable the installation and removal of the rotor 20 to be magnetized. In this case, either or both of the upper device part 31 and the lower device part 41 can move toward and away from each other.

[0025] The upper device section 31 includes an upper magnetizing yoke 32 made of magnetic metal and a coil body 33 integrally attached to the upper magnetizing yoke 32. The upper magnetizing yoke 32 includes a base portion 32a in the shape of an annular plate with a diameter slightly larger than that of the rotor 20 to be magnetized, and eight opposing protrusions 32b arranged at equal intervals in the circumferential direction on the underside of the base portion 32a. Each opposing protrusion 32b abuts or closely faces the upper side surface of the rotor 20 to be magnetized, and is provided corresponding to each rotor magnetic pole portion 26. A magnetizing coil 33a of the coil body 33 is wound around the outer circumferential surface 32c of each opposing protrusion 32b. The coil body 33 includes eight magnetizing coils 33a, the same number as the opposing protrusions 32b.

[0026] Each of the opposing protrusions 32b has a shape similar to that of the outer core portion 25 surrounded by the permanent magnets 23 forming a V-shaped folded-back shape of each rotor magnetic pole portion 26, as viewed in the axial direction of the rotor 20 (see FIG. 6(b)). Specifically, each of the opposing protrusions 32b has a substantially triangular shape with one vertex pointing toward the center of the rotor 20, and the outer peripheral surface 32c of each of the opposing protrusions 32b is configured to have a peripheral surface shape that coincides with the magnet surface 23x of the permanent magnet 23 inside the V shape and the outer peripheral surface 22a of the rotor core 22, as viewed in the axial direction. Note that each of the opposing protrusions 32b may be configured slightly smaller than each of the outer core portions 25. As a result, the main magnetizing magnetic flux entering and exiting from each of the opposing protrusions 32b passes from the outer core portion 25 through the magnet surface 23x of the permanent magnet 23 without passing directly through the axial end face of the permanent magnet 23, magnetizing the permanent magnet 23 in the thickness Wm direction (see FIG. 2).

[0027] As shown in FIG. 6( a), the coil body 33 is configured as one system, with each magnetizing coil 33a being formed by winding a single conductor 33b a predetermined number of times at each of eight locations, and a pair of connecting wires 33c at both ends is connected to a single power supply 34. The coil body 33 is generally annular in shape along the circumferential direction of the upper magnetizing yoke 32 and is attached to each of the opposing protrusions 32b arranged in the circumferential direction. The magnetizing coils 33a in the coil body 33 are wound in alternate opposite directions along the circumferential direction. In other words, when current is applied to the coil body 33 by the power supply 34, the magnetizing coils 33a and the opposing protrusions 32b around which the magnetizing coils 33a are wound are excited so that the polarities of the magnetizing coils 33a and the opposing protrusions 32b alternate along the circumferential direction of the rotor 20. The permanent magnets 23 magnetized by the magnetizing coils 33a and the opposing protrusions 32b alternate in polarity along the circumferential direction of the rotor 20.

[0028] 6(a) and 6(b), in the coil body 33, the crossover wires 33d between circumferentially adjacent magnetizing coils 33a are set to cross between the radially inner vertices of the adjacent opposing convex portions 32b. This configuration allows the crossover wires 33d to be as short as possible. Furthermore, the intersections 33e of the conductor wires 33b that wind around each magnetizing coil 33a are also set at the radially inner vertices of each opposing convex portion 32b, i.e., corresponding to the bent portions 23b of each permanent magnet 23. Because the intersections 33e of the conductor wires 33b in each magnetizing coil 33a are locations where disturbance of the magnetizing magnetic flux is a concern, they are set at the bent portions 23b of the permanent magnets 23 that are farthest from the stator 10 and are therefore least likely to be affected, even if disturbance of the magnetizing magnetic flux should occur.

[0029] The upper device section 31 is configured as described above, and the lower device section 41 has the same configuration as the upper device section 31. That is, as shown in FIGS. 4 to 6 , the lower device section 41 corresponds to the upper magnetizing yoke 32, coil body 33, and power supply 34 of the upper device section 31. The lower device section 41 includes a lower magnetizing yoke 42 having eight opposing protrusions 42b on the upper surface of a base portion 42a, a coil body 43 having eight magnetizing coils 43a, and one power supply 44 for supplying electricity to the coil body 43. The magnetizing coils 43a of the coil body 43 are wound around each opposing protrusion 42b and attached to the outer peripheral surface 42c of each opposing protrusion 42b. The magnetizing coils 43a of the coil body 43 are wound in alternate opposite directions in the circumferential direction. The magnetizing coils 43a of the coil body 43 are configured as a single system by a single conductor 43b, and are energized from the power supply 44 through a pair of connecting wires 43c. The crossover wires 43d of each magnetizing coil 43a are located radially inside the coil body 43, and the intersections 43e of the conductors 43b in each magnetizing coil 43a are located at the vertices radially inside the opposing convex portions 42b, and are similarly configured.

[0030] When magnetizing the rotor 20, the upper device portion 31 and the lower device portion 41 are disposed opposite to each other in the axial direction of the rotor 20 to be magnetized, and the opposing convex portions 32b, 42b of the upper device portion 31 and the lower device portion 41 are positioned opposite to each other in the axial direction. When current is applied by the power supplies 34, 44, the opposing convex portions 32b, 42b and the magnetizing coils 33a, 43a that are opposite to each other in the axial direction on the upper device portion 31 and the lower device portion 41 are excited with the same polarity.

[0031] [Method of magnetizing a permanent magnet using a magnetizing device] 4 to 6, a rotor 20 having an unmagnetized permanent magnet 23 is first placed between the upper and lower parts 31 and 41 of the device when the upper and lower parts 31 and 41 are spaced apart from each other and in an open state. After the rotor 20 to be magnetized is placed, the upper and lower parts 31 and 41 are brought close to each other, and the opposing convex parts 32b and 42b of the upper and lower parts 31 and 41, which will have the same polarity when magnetized, come into contact with or face closely to the upper and lower surfaces of the rotor 20, respectively.

[0032] Next, the power supplies 34, 44 of the upper and lower device portions 31, 41 respectively energize the coil bodies 33, 43. The opposing protrusions 32b, 42b of the upper and lower device portions 31, 41 are alternately excited to opposite polarities in the circumferential direction by energizing the magnetizing coils 33a, 43a. Furthermore, the opposing protrusions 32b, 42b (the magnetizing coils 33a, 43a) of the upper and lower device portions 31, 41 which face each other are excited to the same polarity.

[0033] As shown in FIG. 4, when the opposing convex portions 32b, 42b of the upper and lower device portions 31, 41 are magnetized to the same polarity, for example, S poles, the magnetization magnetic flux along the axially orthogonal direction, including the thickness Wm direction of the permanent magnet 23 (see FIG. 2), is converted into a magnetic flux flow toward each of the opposing convex portions 32b, 42b on both axial sides within the outer core portion 25. As a result, the permanent magnet 23 is magnetized so that the magnet surface 23x side is an N pole. Furthermore, when the opposing convex portions 32b, 42b are magnetized to the N pole, the magnetization magnetic flux along the axial direction from each of the opposing convex portions 32b, 42b within the outer core portion 25 is converted into a magnetic flux flow along the axially orthogonal direction, including the thickness Wm direction of the permanent magnet 23, (not shown). As a result, the permanent magnet 23 is magnetized so that the magnet surface 23x side is an S pole.

[0034] Furthermore, since each of the opposing protrusions 32b, 42b has a shape corresponding to the outer core portion 25 surrounded by each of the permanent magnets 23 having a V-shaped folded shape, the magnetizing magnetic flux entering and exiting from each of the opposing protrusions 32b, 42b does not pass directly through the axial end face of the permanent magnet 23, but the direction of the magnetic flux is suitably converted from the axial direction to a direction perpendicular to the axis within the outer core portion 25 and passes through the magnet surface 23x of the permanent magnet 23. Therefore, the permanent magnet 23 has a magnetization state that makes it easy to magnetize in the thickness Wm direction (see FIG. 2). Furthermore, the intersections 33e, 43e of the conducting wires 33b, 43b that wind around each of the magnetizing coils 33a, 43a are locations where there is concern about disturbance of the magnetizing magnetic flux. However, these intersections are set at the radially inner vertices of each of the opposing convex portions 32b, 42b, i.e., the bends 23b of each permanent magnet 23 that are farthest from the stator 10 and least likely to be affected. Therefore, even if disturbance does occur in the magnetizing magnetic flux, the effect on the magnetization of each permanent magnet 23 is kept small.

[0035] Even with the permanent magnet 23 of this embodiment, which has a generally V-shaped folded shape, it is possible to supply a magnetizing magnetic flux suitable for magnetization from the magnetizer 30 arranged in the axial direction of the rotor 20 to the entire area from the radially outer end 23c to the radially inner bent portion 23b, thereby enabling more effective magnetization of the entire permanent magnet 23. In particular, the deeper the folded shape, such that the embedding depth Lm is greater than the magnetic pole pitch Lp, as in the permanent magnet 23 of this embodiment, the more effective it is.

[0036] Therefore, while permanent magnets magnetized using a conventional method of magnetizing from the radially outer side of the rotor tend to have weaker magnetic force at and near the bent portion, as shown in Figure 7, permanent magnet 23 magnetized using the magnetization method of this embodiment can be magnetized with sufficient magnetic field strength that exceeds the desired lower limit even at bent portion 23b and its vicinity. Even in vertical center portion 23d of bent portion 23b, which is difficult to magnetize in permanent magnet 23, it is possible to magnetize with a magnetic field strength that exceeds the desired lower limit. Thus, with permanent magnet 23 of this embodiment, approximately 95% of the area is magnetized with a magnetic field strength that exceeds the desired lower limit, making it possible to magnetize the entire permanent magnet 23 with sufficient magnetic force.

[0037] The effects of this embodiment will be described. (1) When the permanent magnets 23 embedded in the rotor 20 are magnetized externally using the magnetizing device 30, the opposing convex portions 32b, 42b of the device upper portion 31 and the device lower portion 41 that face each other in the axial direction of the rotor 20 are excited to the same polarity by energizing the magnetizing coils 33a, 43a. At this time, magnetizing magnetic flux of the same polarity is passed through the outer core portion 25 of the rotor core 22 that is located inside the folded shape of the permanent magnet 23 but radially outward of the permanent magnet 23 from both axial sides, thereby magnetizing the permanent magnet 23. As a result, even for a folded permanent magnet 23, a magnetizing magnetic flux suitable for magnetization can be supplied throughout the entire permanent magnet 23, from the radially outer end portion 23c to the bent portion 23b closer to the radially inner side, so that the entire permanent magnet 23 can be magnetized with more effective and sufficient magnetic force.

[0038] (2) When viewed in the axial direction of the rotor 20, each of the opposing protrusions 32b, 42b is configured to be equal to or slightly smaller than the outer core portion 25 located inside the folded shape of the permanent magnet 23 and radially outside the permanent magnet 23. As a result, the magnetizing magnetic flux entering and exiting from each of the opposing protrusions 32b, 42b does not directly pass through the axial end face of the permanent magnet 23, and the direction of the magnetic flux is suitably converted within the outer core portion 25 from the axial direction to the direction perpendicular to the axis, so that the permanent magnet 23 can be suitably magnetized in the thickness Wm direction.

[0039] (3) The crossover wires 33d, 43d between adjacent magnetizing coils 33a, 43a are located radially inward of the coil bodies 33, 43. This makes it possible to minimize the length of the conducting wires 33b, 43b that constitute the coil bodies 33, 43, including the crossover wires 33d, 43d. If the length of the conducting wires 33b, 43b is reduced, the resistance is reduced, which leads to suppression of heat generation in the coil bodies 33, 43 during magnetization, and leads to improved productivity of the rotor 20, including magnetization.

[0040] (4) The intersections 33e, 43e of the conducting wires 33b, 43b that form the magnetizing coils 33a, 43a are set at radially inner positions, i.e., at the bent portions 23b of each permanent magnet 23 that are the farthest from the stator 10 and are least likely to be affected. Therefore, even if disturbance occurs in the magnetizing magnetic flux, the effect on the magnetization of each permanent magnet 23 can be kept small.

[0041] This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility. Although the opposing convex portions 32b, 42b of the magnetizing device 30 are configured to have a shape that matches the shape of each outer core portion 25 when viewed in the axial direction of the rotor 20, the shape of the opposing convex portions 32b, 42b may be a shape that partially matches the shape of the outer core portion 25 or a shape that is different from the shape of the outer core portion 25.

[0042] 8, insertion protrusions 32d, 42d may be provided at the center of the upper magnetizing yoke 32 and the lower magnetizing yoke 42, respectively, and magnetization may be performed by inserting the insertion protrusions 32d, 42d into the shaft insertion hole 22b at the center of the rotor 20 to be magnetized. By providing the insertion protrusions 32d, 42d, part of the magnetizing magnetic flux based on the excitation of the magnetizing coils 33a, 43a flows through the insertion protrusions 32d, 42d, thereby increasing the magnetizing magnetic flux passing through the inner diameter side of the rotor 20. This makes it possible to more effectively magnetize the bent portions 23b of the permanent magnets 23 located on the inner diameter side of the rotor 20 and the vicinity of the bent portions 23b.

[0043] 8, as shown in FIG. 9, the coil bodies 35, 45 of the upper and lower device sections 31, 41 are separated into a first system in which the first magnetizing coils 35a1, 45a1, which are alternately wound in the same direction in the circumferential direction, are formed by a single conductor 35b1, 45b1, and the second system in which the second magnetizing coils 35a2, 45a2 are formed by a single conductor 35b2, 45b2. That is, the system is composed of two separate systems, one for each magnetic pole of the permanent magnet 23 to be magnetized. The first system is connected to first power supply units 36a1, 46a1, and the second system is connected to second power supply units 36a2, 46a2. Magnetization is then performed in two separate processes: a first magnetization process performed by the first system and a second magnetization process performed by the second system. In this way, each of the insertion protrusions 32d, 42d functions as one magnetic pole in each process, thereby further increasing the magnetizing magnetic flux passing through the inner diameter side of the rotor 20, and magnetizing the bent portion 23b of the permanent magnet 23 and its vicinity can be performed more effectively.

[0044] The crossover wires 33d, 43d between the adjacent magnetizing coils 33a, 43a are set at the radially inner position of the coil bodies 33, 43, but may be appropriately changed to, for example, the radially outer position. The intersecting portions 33e, 43e of the conductor wires 33b, 43b that form the magnetizing coils 33a, 43a are set at radially inner positions, but may be appropriately changed to, for example, radially outer positions.

[0045] Because the magnetization device 30 magnetizes the permanent magnets 23 by supplying magnetizing magnetic flux from the axial direction of the rotor 20, when magnetizing a rotor 20 that is long in the axial direction, there is a concern as to whether the permanent magnets 23 located in the middle of the axial direction can be sufficiently magnetized. In such a case, as shown in FIG. 10 , if the axial length of the rotor 20 at which the magnetization device 30 can sufficiently magnetize the permanent magnets 23 is set to L1, it is possible to configure a rotor 20 with an axial length L2 that exceeds L1 by stacking multiple rotor cores 22 with magnetized permanent magnets 23 in the axial direction in two, three, or more rows of magnetization unit blocks with an axial length of L1 or less. Even when the axial length L2 exceeds L1, the permanent magnets 23 are sufficiently magnetized on a block-by-block basis, allowing the rotor 20 to be configured with permanent magnets 23 with sufficient magnetic force overall.

[0046] Although the magnetizing device 30 is configured with the upper device part 31 arranged on the upper side and the lower device part 41 arranged on the lower side, the arrangement of the magnetizing device 30 is not limited to this. The upper device part 31 and the lower device part 41 may be arranged side by side in a horizontal direction or an inclined direction other than the up-down direction.

[0047] The shape of the permanent magnet 23 shown in FIGS. 2 and 7 is an example and may be changed as appropriate. The configuration of the rotating electric machine M shown in FIG. 1 etc. is an example and may be modified as appropriate. The technical concept is described below.

[0048] A rotor manufacturing apparatus for a rotor (20) having permanent magnets (23) embedded in magnet accommodating holes (24) of a rotor core (22) and having a folded shape that is convex inward in the radial direction, the rotor manufacturing apparatus including a magnetizing device (30) that magnetizes the embedded permanent magnets from outside the rotor, the magnetizing device includes a first magnetizing section (31) disposed on one axial side of the rotor and having magnetizing coils (33a, 35a1, 35a2) that supply a magnetizing magnetic flux to the permanent magnet, and a second magnetizing section (41) disposed on the other axial side of the rotor and having magnetizing coils (43a, 45a1, 45a2) that supply a magnetizing magnetic flux to the permanent magnet, the first and second magnetized portions have opposing convex portions (32b, 42b) on outer circumferential surfaces (32c, 42c) on which the magnetizing coil is wound to supply the magnetizing magnetic flux, the opposing convex portion has a shape equivalent to a portion (25) of the rotor core located inside the folded shape of the permanent magnet when viewed in the axial direction of the rotor, and is configured to be equal to or smaller than a size of the portion of the rotor core located inside the folded shape of the permanent magnet, A rotor manufacturing device configured such that, when magnetizing the permanent magnets by passing current through the magnetizing coil, the first and second magnetized portions that face each other in the axial direction of the rotor are excited to the same polarity in the magnetization of the same permanent magnet, and the permanent magnet is magnetized in the thickness direction of the permanent magnet as viewed in the axial direction of the rotor by passing magnetizing magnetic flux of the same polarity from both axial sides of a portion (25) of the rotor core located inside the folded shape of the permanent magnet.

[0049] The permanent magnets each having a radially inwardly convex folded shape are provided in plurality at intervals in the circumferential direction of the rotor core, In each of the first and second magnetizing portions, the plurality of magnetizing coils are configured as one system, each having a single conducting wire wound a predetermined number of times at a plurality of locations, and the winding directions are alternately reversed in the circumferential direction, In each of the first and second magnetizing portions, by passing current through the single conductor connected to a power supply, the magnetizing coils of the first and second magnetizing portions that face each other in the axial direction relative to the rotor are excited to the same polarity, and the magnetizing coils of the first and second magnetizing portions are excited to have alternately different polarities in the circumferential direction, and the magnetizing magnetic flux based on the excitation of the first and second magnetizing portions magnetizes each of the permanent magnets to have alternately different polarities in the circumferential direction of the rotor core.

[0050] The permanent magnets each having a radially inwardly convex folded shape are provided in plurality at intervals in the circumferential direction of the rotor core, In each of the first and second magnetizing sections, the plurality of magnetizing coils are configured as a first system in which first magnetizing coils, which are arranged at every other coil in the circumferential direction and have the same winding direction, are configured with a single conductor, and a second system in which second magnetizing coils, which are arranged at every other coil in the circumferential direction between the first magnetizing coils and have a winding direction opposite to that of the first magnetizing coils, are configured with a single conductor, a first magnetizing step in which, in each of the first and second magnetizing portions, the first magnetizing coils of the first and second magnetizing portions that face each other in the axial direction relative to the rotor are excited to the same polarity by energizing the first system connected to a first power supply device, and every other permanent magnet in the circumferential direction is magnetized to become a magnet of the same polarity by the magnetizing magnetic flux based on the excitation of the first magnetizing coil; a second magnetizing step of energizing the second system connected to a second power supply in each of the first and second magnetizing portions, so that the second magnetizing coils of the first and second magnetizing portions that face each other in the axial direction with respect to the rotor are excited to the same polarity, and magnetizing every other permanent magnet in the circumferential direction between the permanent magnets magnetized in the first magnetizing step by the magnetizing magnetic flux based on the excitation of the second magnetizing coils so that the permanent magnets magnetized in the first magnetizing step become magnets of opposite polarity to the permanent magnets magnetized in the first magnetizing step, The first and second magnetization steps based on the energization of the first and second systems are separately carried out.

[0051] A rotor manufacturing apparatus for a rotor (20) having permanent magnets (23) embedded in magnet accommodating holes (24) of a rotor core (22) and having a folded shape that is convex inward in the radial direction, the rotor manufacturing apparatus including a magnetizing device (30) that magnetizes the embedded permanent magnets from outside the rotor, the magnetizing device includes a first magnetizing section (31) disposed on one axial side of the rotor and having magnetizing coils (33a, 35a1, 35a2) that supply a magnetizing magnetic flux to the permanent magnet, and a second magnetizing section (41) disposed on the other axial side of the rotor and having magnetizing coils (43a, 45a1, 45a2) that supply a magnetizing magnetic flux to the permanent magnet, When the permanent magnets are magnetized by energizing the magnetizing coils, the first and second magnetized portions that face each other in the axial direction of the rotor are excited to the same polarity in the magnetization of the same permanent magnet, and magnetization is performed by passing magnetizing fluxes of the same polarity through the rotor core portion (25) located inside the folded shape of the permanent magnet from both axial sides thereof, The rotor manufacturing device is configured such that the first and second magnetizing portions have insertion portions (32d, 42d) on at least one side that are inserted into the shaft insertion hole (22b) of the rotor, and a portion of the magnetizing magnetic flux based on the excitation of the magnetizing coil flows through the insertion portions.

[0052] The first and second magnetized portions have opposing convex portions (32b, 42b) on their outer circumferential surfaces (32c, 42c) to which the magnetizing coil is wound to supply the magnetizing magnetic flux, The opposing convex portion is configured to be equal to or smaller than a portion of the rotor core located inside the folded shape of the permanent magnet when viewed in the axial direction of the rotor.

[0053] The first and second magnetizing units each include a plurality of the magnetizing coils, The multiple magnetizing coils are configured as first and second systems separated for each magnetic pole of the permanent magnet to be magnetized, and the magnetization process based on the energization of the first and second systems is carried out separately.

[0054] The magnetizing coil is configured as a plurality of coil bodies (33, 43) arranged in the circumferential direction, The crossover wires (33d, 43d) between the adjacent magnetizing coils are set at radially inner positions.

[0055] The magnetizing coil is configured as a plurality of coil bodies (33, 43) arranged in the circumferential direction, The intersecting portions (33e, 43e) of the conductors (33b, 43b) that form the magnetizing coils are located at radially inner positions.

[0056] The rotor is configured by stacking multiple blocks in the axial direction, each block being a magnetization unit of the permanent magnet. A method for manufacturing a rotor (20) having permanent magnets (23) embedded in magnet accommodating holes (24) of a rotor core (22) and having a folded shape that is convex inward in the radial direction, the method comprising: magnetizing the embedded permanent magnets from outside the rotor using a magnetizing device (30), the magnetizing device is configured to include a first magnetizing portion (31) disposed on one axial side of the rotor and having magnetizing coils (33a, 35a1, 35a2) for supplying a magnetizing magnetic flux to the permanent magnet, and a second magnetizing portion (41) disposed on the other axial side of the rotor and having magnetizing coils (43a, 45a1, 45a2) for supplying a magnetizing magnetic flux to the permanent magnet, the first and second magnetized portions have insertion portions (32d, 42d) on at least one side thereof that are inserted into the shaft insertion hole (22b) of the rotor, and are configured such that a part of the magnetizing magnetic flux generated by the excitation of the magnetizing coil flows through the insertion portions; When the permanent magnets are magnetized by energizing the magnetizing coils, the first and second magnetized portions that face each other in the axial direction of the rotor are excited to the same polarity in the magnetization of the same permanent magnet, and magnetization is performed by passing magnetizing fluxes of the same polarity through the rotor core portion (25) located inside the folded shape of the permanent magnet from both axial sides.

[0057] A method for manufacturing a rotor (20) having permanent magnets (23) embedded in magnet accommodating holes (24) of a rotor core (22) and having a folded shape that is convex inward in the radial direction, the method comprising: magnetizing the embedded permanent magnets from outside the rotor using a magnetizing device (30), the magnetizing device is configured to include a first magnetizing portion (31) disposed on one axial side of the rotor and having magnetizing coils (33a, 35a1, 35a2) for supplying a magnetizing magnetic flux to the permanent magnet, and a second magnetizing portion (41) disposed on the other axial side of the rotor and having magnetizing coils (43a, 45a1, 45a2) for supplying a magnetizing magnetic flux to the permanent magnet, the first and second magnetized portions have opposing convex portions (32b, 42b) on outer circumferential surfaces (32c, 42c) on which the magnetizing coil is wound to supply the magnetizing magnetic flux, the opposing convex portion has a shape equivalent to a portion (25) of the rotor core located inside the folded shape of the permanent magnet when viewed in the axial direction of the rotor, and is configured to be equal to or smaller than a size of the portion of the rotor core located inside the folded shape of the permanent magnet, a rotor manufacturing method in which, when magnetizing the permanent magnets by passing current through the magnetizing coils, the first and second magnetized portions that face each other in the axial direction of the rotor are excited to the same polarity in the magnetization of the same permanent magnet, and the permanent magnet is magnetized in the thickness direction of the permanent magnet as viewed in the axial direction of the rotor by passing magnetizing magnetic flux of the same polarity from both axial sides of a portion (25) of the rotor core that is located inside the folded shape of the permanent magnet.

[0058] A rotor manufactured by the rotor manufacturing method described above, The rotor core (22) has a permanent magnet (23) embedded in a magnet accommodating hole (24) of the rotor core (22) and having a folded shape that is convex inward in the radial direction, and the embedded permanent magnet is magnetized from the outside using a magnetizing device (30), The rotor is configured by stacking multiple blocks in the axial direction, each block being a magnetization unit of the permanent magnet that is magnetized by passing magnetizing flux of the same polarity through both axial sides of a portion (25) of the rotor core located inside the folded shape of the permanent magnet. [Explanation of symbols]

[0059] 20 rotor, 22 rotor core, 22b shaft insertion hole, 23 permanent magnet, 24 magnet accommodating hole, 25 outer core portion (rotor core portion), 30 magnetizing device, 31 upper portion of device (first magnetizing portion), 32b opposing convex portion, 32c outer peripheral surface, 32d insertion portion (insertion protrusion), 33 coil body, 33a magnetizing coil, 33b conductor wire, 33d crossover wire, 33e intersection portion, 35a1 first magnetizing coil (magnetizing coil), 35a2 second magnetizing coil (magnetizing coil), 41 lower portion of device (second magnetizing portion), 42b opposing convex portion, 42c outer peripheral surface, 42d insertion portion (insertion protrusion), 43 coil body, 43a magnetizing coil, 43b conductor wire, 43d crossover wire, 43e Intersection: 45a1 is a first magnetizing coil (magnetizing coil), 45a2 is a second magnetizing coil (magnetizing coil).

Claims

1. A rotor manufacturing apparatus for a rotor (20) having permanent magnets (23) embedded in magnet accommodating holes (24) of a rotor core (22) and having a folded, convex shape on the inside in the radial direction, the rotor manufacturing apparatus including a magnetizing device (30) that magnetizes the embedded permanent magnets from outside the rotor, the magnetizing device includes a first magnetizing portion (31) disposed on one axial side of the rotor and having magnetizing coils (33a, 35a1, 35a2) that supply magnetizing flux to the permanent magnet, and a second magnetizing portion (41) disposed on the other axial side of the rotor and having magnetizing coils (43a, 45a1, 45a2) that supply magnetizing flux to the permanent magnet, the first and second magnetized portions have opposing convex portions (32b, 42b) on their outer circumferential surfaces (32c, 42c) to which the magnetizing coil is wound in order to supply the magnetizing magnetic flux; A portion of the rotor core located inside the folded shape of the permanent magnet and radially outward of the permanent magnet is an outer core portion (25), the opposing convex portion is configured to have a peripheral surface shape such that, when viewed in the axial direction of the rotor, the outer peripheral surface of the opposing convex portion matches the inner magnet surface of the folded shape of the permanent magnet and the outer peripheral surface of the radially outer side of the outer core portion, or the opposing convex portion is configured to be smaller than the outer core portion when viewed in the axial direction of the rotor, When the permanent magnets are magnetized by energizing the magnetizing coils, the first and second magnetized portions that face each other in the axial direction of the rotor are excited to the same polarity in the magnetization of the same permanent magnet, and the permanent magnet is magnetized in the thickness direction of the permanent magnet as viewed in the axial direction of the rotor by passing magnetizing magnetic flux of the same polarity from both axial sides of the outer core portion (25) of the rotor core that is located inside the folded shape of the permanent magnet, The magnetizing coil is configured as a plurality of coil bodies (33, 43) arranged in a circumferential direction, The rotor manufacturing device, wherein the intersections (33e, 43e) of the conductors (33b, 43b) that wind the magnetizing coil are set at radially inner positions and at positions that correspond to the bent portions (23b) that are the folded portions of the permanent magnets (23) that have the folded shape.

2. a plurality of the permanent magnets each having a folded shape that is convex toward the inside in the radial direction are provided at intervals from each other in the circumferential direction of the rotor core, In each of the first and second magnetizing portions, the plurality of magnetizing coils are configured as one system, each having a single conducting wire wound a predetermined number of times at a plurality of locations, and are wound in alternately opposite directions in the circumferential direction, 2. The rotor manufacturing apparatus according to claim 1, wherein, in each of the first and second magnetizing portions, by passing current through the single conductor connected to a power supply, the magnetizing coils of the first and second magnetizing portions that face each other in the axial direction with respect to the rotor are excited to the same polarity, and the magnetizing coils of the first and second magnetizing portions are excited to have opposite polarities alternately in the circumferential direction, and the magnetizing magnetic flux based on the excitation of the first and second magnetizing portions magnetizes each of the permanent magnets to have magnets of opposite polarities alternately in the circumferential direction of the rotor core.

3. the first and second magnetizing units each include a plurality of the magnetizing coils, 2. The rotor manufacturing apparatus according to claim 1, wherein the plurality of magnetizing coils are configured as first and second systems separated for each magnetic pole of the permanent magnet to be magnetized, and the magnetization process based on the energization of the first and second systems is carried out separately.

4. The magnetizing coil is configured as a plurality of coil bodies (33, 43) arranged in a circumferential direction, 4. The rotor manufacturing device according to claim 1, wherein a crossover wire (33d, 43d) between adjacent magnetizing coils is set at a radially inner position.

5. 5. The rotor manufacturing apparatus according to claim 1, wherein the rotor is configured by stacking a plurality of blocks in the axial direction, each block being a magnetization unit of the permanent magnet.

6. A method for manufacturing a rotor (20) having permanent magnets (23) embedded in magnet accommodating holes (24) of a rotor core (22) and having a folded shape that is convex inward in the radial direction, the method comprising the steps of: magnetizing the embedded permanent magnets from the outside of the rotor using a magnetizing device (30); The magnetizing device is configured to include a first magnetizing portion (31) disposed on one axial side of the rotor and having magnetizing coils (33a, 35a1, 35a2) for supplying a magnetizing flux to the permanent magnet, and a second magnetizing portion (41) disposed on the other axial side of the rotor and having magnetizing coils (43a, 45a1, 45a2) for supplying a magnetizing flux to the permanent magnet, the first and second magnetized portions have opposing convex portions (32b, 42b) on their outer circumferential surfaces (32c, 42c) to which the magnetizing coil is wound in order to supply the magnetizing magnetic flux; A portion of the rotor core located inside the folded shape of the permanent magnet and radially outward of the permanent magnet is an outer core portion (25), the opposing convex portion is configured to have a peripheral surface shape such that, when viewed in the axial direction of the rotor, the outer peripheral surface of the opposing convex portion matches the inner magnet surface of the folded shape of the permanent magnet and the outer peripheral surface of the radially outer side of the outer core portion, or the opposing convex portion is configured to be smaller than the outer core portion when viewed in the axial direction of the rotor, The magnetizing coil is configured as a plurality of coil bodies (33, 43) arranged in a circumferential direction, Intersections (33e, 43e) of the conductors (33b, 43b) that wind the magnetizing coil are set at radially inner positions and at positions that correspond to bent portions (23b) that are folded back portions of the permanent magnet (23), a rotor manufacturing method in which, when magnetizing the permanent magnet by passing current through the magnetizing coil, the first and second magnetized portions that face each other in the axial direction of the rotor are excited to the same polarity in the magnetization of the same permanent magnet, and the permanent magnet is magnetized in the thickness direction of the permanent magnet when viewed in the axial direction of the rotor by passing magnetizing magnetic flux of the same polarity from both axial sides of the outer core portion (25) of the rotor core that is located inside the folded shape of the permanent magnet.

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