Permanent magnet rotor and method for manufacturing permanent magnet rotor

Abstract

This permanent magnet rotor (10) comprises: a rotary shaft (1); an inner circumferential-side magnet (2) which is a cylindrical bonded magnet that holds the rotary shaft (1); and an outer circumferential-side magnet (3) which is a cylindrical bonded magnet provided on the outer circumferential side of the inner circumferential-side magnet (2). The inner circumferential-side magnet (2) has, at one axial end thereof, a plurality of first recesses (24) that are disposed at an equal interval in the circumferential direction.

Description

Permanent magnet rotor and method of manufacturing the same

[0001] The present disclosure relates to permanent magnet rotors and methods of manufacturing permanent magnet rotors.

[0002] Bonded magnets can be manufactured by injection molding in the same way as general resin materials. For this reason, permanent magnet rotors can be easily manufactured using bonded magnets, and they are widely used, for example, as permanent magnet rotors for air conditioner fan motors. In order to meet the demand for energy conservation in recent years, there is a strong demand for stronger magnetic force, and although ferrite bonded magnets are generally used, rare earth bonded magnets are also sometimes used. However, rare earth bonded magnets are expensive materials.

[0003] Patent Document 1 employs a two-layer permanent magnet rotor with a ferrite bonded magnet on the inner periphery and a rare earth magnetic bonded magnet on the outer periphery, achieving both performance and cost. Patent Document 1 describes that when the outer periphery magnet is molded, the magnetic poles formed on the inner periphery magnet are attracted and fixed in position by the magnetic attractive force generated from the surface of the molding die for the outer periphery magnet.

[0004] Japanese Patent Application Laid-Open No. 2005-151757

[0005] When molding magnets into a two-layer structure, it is necessary to align the magnetic pole phase of the inner magnet with the magnetic pole phase of the outer magnet. However, in Patent Document 1, when the outer magnet is thick, the accuracy of positioning by magnetic attraction decreases, and the magnetic pole positions of the outer magnet and inner magnet become misaligned, resulting in issues such as a decrease in surface magnetic flux density and distortion of the magnetic flux, which increases torque ripple in the motor in which it is installed.

[0006] The present disclosure has been made in view of the above, and has an object to provide a permanent magnet rotor in which the magnetic pole phases of the inner and outer circumferential magnets match.

[0007] In order to solve the above-mentioned problems and achieve the object, the permanent magnet rotor of the present disclosure includes a rotating shaft, an inner magnet which is a cylindrical bonded magnet that holds the rotating shaft, and an outer magnet which is also a cylindrical bonded magnet that is provided on the outer periphery of the inner magnet. The inner magnet has a plurality of first recesses at one axial end that are equally spaced circumferentially.

[0008] The permanent magnet rotor of the present disclosure has the effect of being able to obtain a permanent magnet rotor in which the magnetic pole phases of the inner circumferential side magnets and the outer circumferential side magnets match.

[0009] 1 is a perspective view showing the configuration of the permanent magnet rotor of embodiment 1; sectional view showing the configuration of one end of the permanent magnet rotor of embodiment 1; sectional view showing the configuration of the other end of the permanent magnet rotor of embodiment 1; top view showing the positional relationship between the magnetic field alignment magnetic field lines and weld lines in the permanent magnet rotor of embodiment 1; schematic plan view showing the positional relationship between one end of the permanent magnet rotor of embodiment 1 and a second magnetic field alignment mold; plan view showing the positional relationship between the first recess, magnetic pole center, and weld line in the magnet part of the permanent magnet rotor of embodiment 1; schematic plan view showing the positional relationship between the other end of the permanent magnet rotor of embodiment 1 and a second magnetic field alignment mold; 1. Plan view showing the positional relationship of the magnetic pole centers and weld lines. 2. Schematic diagram showing the magnetic flux distribution on the outer peripheral surface of the permanent magnet rotor of embodiment 1. 3. Process diagram showing the manufacturing process of the permanent magnet rotor in embodiment 2. 4. Cross-sectional view showing the first mold used in the manufacturing process of embodiment 2 in a disassembled state. 5. Plan view showing the first magnetic field orientation mold of the first mold of embodiment 2 in a cross-sectional view showing the first mold used in the manufacturing process of embodiment 2 in an assembled state. 6. Cross-sectional view showing the inner peripheral magnet manufactured using the first mold of embodiment 2. 7. Cross-sectional view showing the second mold used in the manufacturing process of embodiment 2 in a disassembled state. 8. Cross-sectional view showing the second mold used in the manufacturing process of embodiment 2 in an assembled state. 9. Cross-sectional view showing the outer peripheral magnet manufactured using the second mold of embodiment 2.

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A permanent magnet rotor and a method for manufacturing the permanent magnet rotor according to an embodiment will be described in detail below with reference to the accompanying drawings.

[0011] Embodiment 1. Fig. 1 is a perspective view showing the configuration of permanent magnet rotor 10 according to embodiment 1. Fig. 2 is a cross-sectional view showing the configuration of permanent magnet rotor 10 according to embodiment 1. Fig. 3 is a cross-sectional view showing the configuration of one end of permanent magnet rotor 10 according to embodiment 1. Fig. 3 is a cross-sectional view taken along III-III in Fig. 2. Fig. 4 is a perspective view showing the configuration of the other end of permanent magnet rotor 10 according to embodiment 1.

[0012] As shown in FIGS. 1 to 4 , the permanent magnet rotor 10 has a rotating shaft 1 , an inner magnet 2 , and an outer magnet 3 .

[0013] As shown in FIG. 2 , the inner magnet 2 has an inner shaft holding portion 21 that holds the rotating shaft 1, a cylindrical magnetic portion 22 on the outer circumference, and a connecting portion 23 that connects the magnetic portion 22 and the shaft holding portion 21. As shown in FIG. 3 , a plurality of first recesses 24 are provided on the inner circumference of one axial end of the magnetic portion 22. In the first embodiment, since the permanent magnet rotor 10 has ten magnetic poles, five first recesses 24, which is half the number of magnetic poles, are provided and are evenly spaced circumferentially. The number of magnetic poles is the sum of the number of north poles and the number of south poles. The five first recesses 24 have the same shape and are provided only at one axial end of the magnetic portion 22.

[0014] At the other axial end of the magnetic force portion 22, i.e., the end opposite to the end where the first recesses 24 are formed, a plurality of semicircular second recesses 25 recessed from the outer edge toward the inner periphery are provided, as shown in FIG. 4 . In embodiment 1, since the permanent magnet rotor 10 has ten magnetic poles, five second recesses 25, which is half the number of magnetic poles, are provided and are evenly spaced circumferentially. A cross section of the second recesses 25 taken perpendicular to the axial direction of the rotating shaft 1 is semicircular. The five second recesses 25 have the same shape and are provided only at the other axial end of the magnetic force portion 22.

[0015] The outer magnet 3 has a cylindrical shape. The outer magnet 3 has multiple gate connection portions 4 and multiple semicircular protrusions 31 provided on the inner side of the gate connection portions 4. The gate connection portions 4 are connected to the gates, which are the resin inlets of the injection molding machine. As shown in FIG. 2 , the semicircular protrusions 31 protruding on the inner side are provided only on the other axial end of the outer magnet 3, i.e., the end on the side where the second recesses 25 are formed. The multiple semicircular protrusions 31 fit into the multiple semicircular second recesses 25 of the inner magnet 2.

[0016] The inner magnet 2 and the outer magnet 3 are bonded magnets formed by insert injection molding with an in-mold magnetic field orientation. The magnetic force portion 22 of the inner magnet 2 and the outer magnet 3 form the magnet portion 11 that functions as the magnet of the permanent magnet rotor 10. The magnetic field orientation of the inner magnet 2 and the outer magnet 3 is the same, and the inner magnet 2 and the outer magnet 3 have the same magnetic poles.

[0017] FIG. 5 is a top view showing the positional relationship between magnetic field alignment magnetic field lines and weld lines in permanent magnet rotor 10 of embodiment 1. FIG. 5 shows the permanent magnet rotor 10 placed in a magnetic field alignment mold. The magnetic field alignment mold shown in FIG. 5 corresponds to first magnetic field alignment mold 43 and second magnetic field alignment mold 53 described below. Multiple tooth portions 45 of the magnetic field alignment mold are shown around the permanent magnet rotor 10. Magnetic field alignment magnets (not shown) are arranged between the tooth portions 45. FIG. 5 shows concentric magnetic field lines 7 formed in the magnet portion 11 of permanent magnet rotor 10 by the magnetic field alignment mold.

[0018] As shown in FIG. 5 , in the first embodiment, the permanent magnet rotor 10 has ten magnetic poles. Since there are ten magnetic poles, magnetic field lines 7 are generated in ten locations. Five first recesses 24 are provided at equal intervals in positions facing the plurality of tooth portions 45. In the first embodiment, the first recesses 24 are provided so as to face five of the ten tooth portions 45. The weld lines 6 are located midway between the plurality of tooth portions 45. The inter-pole space 8, which is the midpoint between adjacent magnetic poles, is magnetically oriented so as to be aligned with the weld lines 6. In the first embodiment, the magnetic resin material is simultaneously injected through the plurality of gate connection portions 4, so five weld lines 6 are formed midway between adjacent gate connection portions 4 in the circumferential direction.

[0019] Next, the first recess 24 provided on the inner circumference of one end of the magnetic portion 22 of the inner magnet 2 will be described. The outer magnet 3 is insert injection molded on the outer circumference of the inner magnet 2. At that time, the inner magnet 2 needs to be set in the mold so that its rotational phase matches that of a second magnetic field orientation magnet placed in a second magnetic field orientation mold 53 (described later) in order to magnetically orient the outer magnet 3. The first recess 24 provided on the inner circumference of the magnetic portion 22 of the inner magnet 2 is set in alignment with a protrusion 62 provided in a second mold 50 (described later) in which the second magnetic field orientation mold 53 is placed, allowing for highly accurate positioning.

[0020] Next, the circumferential position of the first recesses 24 will be described with reference to FIGS. 6 and 7 . FIG. 6 is a schematic plan view showing the positional relationship between one end of the permanent magnet rotor 10 of the first embodiment and the second magnetic field orientation mold 53. FIG. 7 is a plan view showing the positional relationship between the first recesses 24, the magnetic pole centers 12, and the weld lines 6 in the magnet section 11 of the permanent magnet rotor 10 of the first embodiment. The second magnetic field orientation mold 53 is a mold for magnetizing the outer magnets 3 by insert resin molding. The second magnetic field orientation mold 53 has a cylindrical outer periphery yoke 54, multiple teeth 55, and multiple magnetic field orientation magnets 56. The multiple teeth 55 extend from the outer periphery yoke 54 toward the inner circumference and are evenly spaced in the circumferential direction. The multiple magnetic field orientation magnets 56 are arranged between adjacent teeth 55. The magnetic field orientation magnets 56 are alternately arranged so that the north and south poles face the circumferential direction and the north poles and south poles face each other between adjacent magnetic field orientation magnets 56. By arranging the magnetic field orientation magnets 56 in this manner, north and south poles are formed on adjacent tooth portions 55, and a magnetic field is formed from the adjacent tooth portions 55 to the magnet portion 11 in the direction of the magnetic field lines 7 (see Figure 7).

[0021] Each first recess 24 of the inner circumference side magnet 2 is positioned opposite a tooth portion 55 of the second magnetic field orientation mold 53. That is, due to the magnetic field orientation by the second magnetic field orientation mold 53, a magnetic pole center 12 is formed in the portion of the magnet portion 11 facing each tooth portion 55, as shown in Figure 7, and no magnetic pole is formed on the inner circumference side, so each first recess 24 is positioned at a position where the magnetic force is zero on the inner circumference side of the magnet portion 11. The magnetic pole center 12 is the center position of the magnetic pole.

[0022] Next, the semicircular convex portion 31 of the outer magnet 3 and the semicircular second recess 25 of the inner magnet 2 will be described in detail. FIG. 8 is a schematic plan view showing the positional relationship between the other end of the permanent magnet rotor 10 of embodiment 1 and the second magnetic field orientation mold 53. FIG. 9 is a plan view showing the positional relationship between the convex portion 31, magnetic pole center 12, and weld line 6 in the magnet portion 11 of the permanent magnet rotor 10 of embodiment 1. The outer magnet 3 is insert injection molded to fill the second recess 25 of the inner magnet 2. In the permanent magnet rotor 10 of embodiment 1, the convex portion 31 of the outer magnet 3 is fitted into the second recess 25 of the inner magnet 2. This improves the joining strength between the inner magnet 2 and the outer magnet 3 in the rotational direction. Furthermore, because the convex portion 31 and the second recess 25 are fitted together at their axial ends, the axial tensile strength between the inner magnet 2 and the outer magnet 3 can be improved.

[0023] As shown in Fig. 8, the five protrusions 31 of the outer magnet 3 are positioned midway between adjacent tooth portions 55 of the second magnetic field orientation mold 53. In other words, as shown in Fig. 9, magnetic pole centers 12 are formed in the portions of the magnet portion 11 facing each tooth portion 55 due to magnetic field orientation by the second magnetic field orientation mold 53, and therefore each protrusion 31 is positioned midway between adjacent magnetic pole centers 12 in the magnet portion 11.

[0024] FIG. 10 is a schematic diagram showing the magnetic flux distribution on the outer peripheral surface of permanent magnet rotor 10 according to the first embodiment. The horizontal axis represents angle θ, and the vertical axis represents magnetic flux Φ. A to C are north poles, and C to E are south poles. In the case of a 10-pole system, if A is 0°, C is 36°, and E is 72°. The magnetic flux distribution is sinusoidal. A is the boundary between the south and north poles, and C is the boundary between the north and south poles. B is the position of maximum magnetic flux at the north pole, which is the magnetic pole center of the north pole. D is the position of maximum magnetic flux at the south pole, which is the magnetic pole center of the south pole. As shown in FIG. 6 , when first recesses 24 are magnetized at an angle facing tooth portions 55, the angle of tooth portions 55 on the outer peripheral surface of permanent magnet rotor 10 corresponds to the center of the magnetic poles, and the midpoint between adjacent tooth portions 55 corresponds to the boundary between the north and south poles. Therefore, either the magnetic pole center of the north pole or the magnetic pole center of the south pole is disposed at an angle corresponding to the first recess 24 .

[0025] As described above, in the first embodiment, the first recesses 24 are evenly spaced at half the number of magnetic poles of the permanent magnet rotor 10 and are positioned at positions where the magnetic force of the magnetic field orientation of the mold is zero, thereby minimizing magnetic distortion. The first recesses 24 are positioned at one axial end of the inner magnet 2. This arrangement enables positioning when molding the permanent magnet rotor 10 from above and below in the axial direction using an upper mold and a lower mold. The first recesses 24 are also formed on the inner circumferential surface of the magnetic force portion 22 of the inner magnet 2. This arrangement reduces the effect on the magnetic flux of the permanent magnet rotor 10.

[0026] The number of first recesses 24 is, for example, five when the number of magnetic poles is 10, and ten when the number of magnetic poles is 20. Alternatively, the number of first recesses 24 may be five when the number of magnetic poles is 20. That is, the number of first recesses 24 may be 1 / (2N) (N is a natural number) of the number of magnetic poles. Furthermore, it is more desirable to have the number of first recesses 24 be a prime number. By having the number of first recesses 24 be a prime number, the mode of the electromagnetic excitation force can be suppressed. For example, if there are ten first recesses 24 when the number of magnetic poles is 20, two-fold rotational symmetry occurs around the entire circumference of the rotation axis, generating an electromagnetic excitation force with twice the frequency per circumference. By having the number of first recesses 24 be a prime number, only frequencies corresponding to the entire circumference and the number of first recesses 24 are generated, thereby suppressing excitation forces of unnecessary frequencies.

[0027] Embodiment 2 In Embodiment 2, a method of manufacturing a permanent magnet rotor 10 will be described. FIG. 11 is a process diagram showing the manufacturing process of a permanent magnet rotor 10 in Embodiment 2. FIG. 12 is a cross-sectional view showing a disassembled state of a first mold 40 used in the manufacturing process of Embodiment 2. FIG. 13 is a plan view showing a first magnetic field alignment mold 43 of the first mold 40 of Embodiment 2. FIG. 14 is a cross-sectional view showing an assembled state of the first mold 40 used in the manufacturing process of Embodiment 2. FIG. 15 is a cross-sectional view showing an inner circumference side magnet 2 manufactured using the first mold 40 of Embodiment 2. FIG. 16 is a cross-sectional view showing a disassembled state of a second mold 50 used in the manufacturing process of Embodiment 2. FIG. 17 is a cross-sectional view showing an assembled state of the second mold 50 used in the manufacturing process of Embodiment 2. FIG. 18 is a cross-sectional view showing an outer circumference side magnet 3 manufactured using the second mold 50 of Embodiment 2.

[0028] As shown in FIG. 18, the permanent magnet rotor 10 is manufactured by forming an inner magnet 2 around a rotating shaft 1 and forming an outer magnet 3 on the outer periphery of the inner magnet 2.

[0029] First Mold Arrangement Step (Step S1) As shown in FIG. 12 , the first mold 40 has a first upper mold 41, a first lower mold 42, and a first magnetic field alignment mold 43. As shown in FIG. 14 , the rotation shaft 1 is inserted into the central holes of the first upper mold 41 and the first lower mold 42 to form a first space 40a surrounded by the first upper mold 41 and the first lower mold 42. The first magnetic field alignment mold 43 is arranged on the outer periphery of the first upper mold 41 and the first lower mold 42. The first lower mold 42 has a plurality of protrusions 61 for forming a plurality of first recesses 24. The first upper mold 41 also has a plurality of protrusions 63 for forming a plurality of second recesses 25.

[0030] The first magnetic field alignment mold 43 is a mold for insert-molding the inner circumference side magnet 2 with resin to magnetize it. As shown in FIG. 13 , the first magnetic field alignment mold 43 has a cylindrical outer periphery yoke 44, multiple teeth 45, and multiple magnetic field alignment magnets 46. The multiple teeth 45 extend from the outer periphery yoke 44 toward the inner circumference and are evenly spaced in the circumferential direction. The multiple magnetic field alignment magnets 46 are arranged between adjacent teeth 45. The magnetic field alignment magnets 46 are alternately arranged so that the north and south poles face the circumferential direction and the north poles and south poles face each other between adjacent magnetic field alignment magnets 46. By arranging the magnetic field alignment magnets 46 in this manner, north and south poles are formed in adjacent teeth 45, and a magnetic field is formed in the direction of magnetic field lines 7 from the adjacent teeth 45 toward the center.

[0031] Inner Magnet Forming Process (Step S2) With a magnetic field formed in the first space 40a, a first magnetic resin material is injection molded through the gate of the first upper mold 41. The first magnetic resin material is, for example, an anisotropic ferrite-bonded magnet material. As a result, as shown in FIG. 15 , the anisotropic magnetic resin material is oriented in the direction of the magnetic field lines 7, and an inner magnet 2 is formed around the rotation axis 1, magnetized to correspond to the shape of the first space 40a and the direction of the magnetic field lines 7 formed by the magnetic field alignment magnet 46. A first recess 24 is formed at one axial end of the inner magnet 2 by the convex portion 61 of the first lower mold 42. A second recess 25 is formed at the other axial end of the inner magnet 2 by the convex portion 63 of the first upper mold 41.

[0032] Second Mold Arrangement Process (Step S3) As shown in Figure 16, the second mold 50 has a second upper mold 51 having a gate, a second lower mold 52 having a protrusion 62 that fits into the first recess 24, and a second magnetic field alignment mold 53. As shown in Figure 17, the rotation shaft 1 held by the inner circumference side magnet 2 is inserted into the center hole of the second upper mold 51 and the center hole of the second lower mold 52 to form a second space 50a surrounded by the second upper mold 51 and the second lower mold 52. The second magnetic field alignment mold 53 is arranged on the outer periphery of the second upper mold 51 and the second lower mold 52. The second magnetic field alignment mold 53 has the same shape and the same number of magnetic poles as the first magnetic field alignment mold 43. At this time, the rotational direction is positioned by the first recess 24 of the inner magnet 2 and the protrusion 62 provided on the second lower mold 52 of the second mold 50 so that the magnetic pole center 12 formed on the inner magnet 2 coincides with the magnetic pole center 12 formed by the second magnetic field orientation mold 53.

[0033] Outer Magnet Forming Process (Step S4) With a magnetic field formed in the second space 50a, a second magnetic resin material is injection-molded through multiple gates of the second upper mold 51. The second magnetic resin material is, for example, an anisotropic rare earth bonded magnet material. This causes the second magnetic resin material to be injected into the second space 50a through multiple gate connections 4. As a result, as shown in FIG. 18 , the anisotropic magnetic resin material is oriented in the direction of the magnetic field lines 7, and outer magnets 3 magnetized to correspond to the shape of the second space 50a and the direction of the magnetic field lines 7 formed by the magnetic field alignment magnets 56 are formed on the outer periphery of the inner magnets 2, completing the permanent magnet rotor 10. Multiple protrusions 31 that fit into the multiple second recesses 25 are formed at one end of the outer magnets 3.

[0034] According to embodiment 2, the rotational direction is positioned by the first recess 24 of the inner magnet 2 and the protrusion 62 provided on the second lower mold 52 of the second mold 50 so that the magnetic pole center 12 formed on the inner magnet 2 coincides with the magnetic pole center 12 formed by the second magnetic field orientation mold 53, so that a permanent magnet rotor 10 can be easily obtained in which the magnetic pole phases of the inner magnet 2 and the outer magnet 3 coincide.

[0035] In the above, the convex portion 62 that fits into the first recess 24 is provided on the second lower mold 52 of the second mold 50, but the convex portion 62 that fits into the first recess 24 may also be provided on the second upper mold 51 of the second mold 50.

[0036] The configurations shown in the above embodiments are examples of the contents of the present disclosure, and may be combined with other known technologies, and parts of the configurations may be omitted or modified within the scope of the gist of the present disclosure.

[0037] REFERENCE SIGNS LIST 1 Rotating shaft, 2 Inner circumference side magnet, 3 Outer circumference side magnet, 4 Gate connection portion, 6 Weld line, 7 Magnetic field lines, 8 Inter-pole, 10 Permanent magnet rotor, 11 Magnet portion, 12 Magnetic pole center, 21 Shaft holding portion, 22 Magnetic force portion, 23 Connection portion, 24 First recess, 25 Second recess, 31, 61, 62, 63 Convex portion, 40 First mold, 40a First space, 41 First upper mold, 42 First lower mold, 43 First magnetic field orientation mold, 44, 54 Outer circumference yoke, 45, 55 Tooth portion, 46, 56 Magnetic field orientation magnet, 50 Second mold, 50a Second space, 51 Second upper mold, 52 Second lower mold, 53 Second magnetic field orientation mold.

Claims

1. A rotation axis; An inner circumferential magnet which is a cylindrical bonded magnet that holds the rotating shaft; An outer circumferential magnet, which is a cylindrical bonded magnet provided on the outer circumferential side of the inner circumferential magnet; Equipped with The inner circumference magnet is A plurality of first recesses are disposed at one end in an axial direction at equal intervals in a circumferential direction, A permanent magnet rotor characterized in that the angle at which the multiple first recesses are arranged, relative to the rotation axis, is arranged to coincide with the angle of the magnetic pole centers of the N pole or S pole of the inner side magnet and the outer side magnet.

2. A permanent magnet rotor as described in claim 1, characterized in that the multiple first recesses are arranged at positions where the magnetic force on the inner side of the inner magnet is zero.

3. 2. The permanent magnet rotor according to claim 1, characterized in that the number of the first recesses is 1 / (2N) of the number of magnetic poles formed on the inner circumference side magnet and the outer circumference side magnet, where N is a natural number.

4. 4. The permanent magnet rotor according to claim 3, wherein the number of the first recesses is a prime number.

5. The first recesses are provided at one end of the inner magnet in the axial direction, the inner circumference side magnet has a plurality of second recesses on the outer circumference side of the other end in the axial direction, The outer periphery magnet is 2. The permanent magnet rotor according to claim 1, further comprising a plurality of protrusions that protrude to the inner periphery and fit into the plurality of second recesses of the inner periphery magnet.

6. A first step of arranging a first mold having a first upper mold, a first lower mold, and a first magnetic field orientation mold for forming an inner circumference side magnet, which is a bonded magnet, having a plurality of first recesses arranged at equal intervals in the circumferential direction at one end in the axial direction, around a rotation axis; a second step of forming the inner circumference side magnet, which holds the rotating shaft and has a plurality of the first recesses at one end in the axial direction, by injection molding a first magnetic resin material into a first space surrounded by the first mold; A third step of disposing a second mold having a second upper mold, a second lower mold, and a second magnetic field orientation mold for forming an outer circumferential magnet, which is a bonded magnet, around the inner circumferential magnet; a fourth step of forming the outer circumferential magnet on the outside of the inner circumferential magnet that holds the rotating shaft by injection molding a second magnetic resin material into a second space surrounded by the second mold; Equipped with an angle at which the plurality of first recesses are arranged, in relation to an angle centered on the rotation axis, is arranged to coincide with an angle of a magnetic pole center of the N pole or the S pole of the inner circumference side magnet and the outer circumference side magnet; the second die has a plurality of protrusions that fit into the first recesses of the inner circumference side magnet, A manufacturing method for a permanent magnet rotor, characterized in that in the fourth step, a plurality of the convex portions and a plurality of the first concave portions are positioned in the rotational direction to position the inner side magnet and the second mold.