Permanent magnet rotor

Abstract

This permanent magnet rotor (10) comprises: a rotating shaft (1); an inner circumferential side magnet (2) that has a plurality of recesses (24) on the outer circumferential side and is an annular bonded magnet holding the rotating shaft (1); and an outer circumferential side magnet (3) that is an annular bonded magnet provided on the outer circumferential side of the inner circumferential side magnet (2). The outer circumferential side magnet (3) has a plurality of protrusions (31) that protrude toward the inner circumferential side and engage with the plurality of recesses (24) of the inner circumferential side magnet (2).

Description

[Technical field]

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

[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 saving in recent years, there is a strong demand for stronger magnetic force of magnets, and although ferrite bonded magnets are generally used, rare earth bonded magnets are sometimes used. However, rare earth bonded magnets are expensive materials.

[0003] In Patent Document 1, a two-layer permanent magnet rotor is used that has a ferrite bonded magnet on the inner circumference and a rare earth magnetic bonded magnet on the outer circumference, thereby achieving both performance and cost. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-151757 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in Patent Document 1, because the materials on the inner and outer circumferential sides are different materials, there is a problem in that the bond strength between the inner bonded magnet and the outer bonded magnet is weak.

[0006] The present disclosure has been made in consideration of the above, and has an object to provide a permanent magnet rotor that improves the joint strength between the inner magnets and the outer magnets. [Means for solving the problem]

[0007] In order to solve the above 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 having multiple recesses on its outer periphery and holding the rotating shaft, and an outer magnet which is a cylindrical bonded magnet provided on the outer periphery of the inner magnet. The outer magnet is characterized by having multiple protrusions that protrude to the inner periphery and fit into the multiple recesses of the inner magnet. The multiple recesses are provided on only one axial end of the inner magnet, and the multiple protrusions are provided on only one axial end of the outer magnet. Effect of the Invention

[0008] The permanent magnet rotor according to the present disclosure has the effect of improving the joint strength between the inner circumference side magnets and the outer circumference side magnets. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing a configuration of a permanent magnet rotor according to a first embodiment; [Diagram 2] FIG. 1 is a side view showing a configuration of a permanent magnet rotor according to a first embodiment. [Diagram 3] FIG. 1 is a top view showing a configuration of a permanent magnet rotor according to a first embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing the configuration of the permanent magnet rotor according to the first embodiment, taken along line IV-IV of FIG. [Diagram 5] FIG. 1 is a perspective view showing a configuration of an inner circumferential magnet of a permanent magnet rotor according to a first embodiment. [Figure 6] FIG. 1 is a perspective view showing a configuration of an outer circumferential magnet of a permanent magnet rotor according to a first embodiment; [Figure 7] FIG. 1 is a top view showing the positional relationship between magnetic field-oriented magnetic field lines, a gate connection portion, and a weld line in a permanent magnet rotor according to a first embodiment. [Figure 8] FIG. 1 is a partially enlarged plan view for explaining dimensions of a permanent magnet rotor according to a first embodiment; [Figure 9] FIG. 1 is a partially enlarged cross-sectional view for explaining dimensions of a permanent magnet rotor according to the first embodiment; [Figure 10]FIG. 1 is a schematic plan view showing the positional relationship between a permanent magnet rotor and a second magnetic field orientation mold according to the first embodiment; [Figure 11] FIG. 1 is a plan view showing the positional relationship of a gate connection portion, a magnetic pole center, and a weld line in a magnet portion of a permanent magnet rotor according to a first embodiment. [Figure 12] FIG. 11 is a plan view showing another positional relationship between the gate connection portion, the magnetic pole center, and the weld line in the magnet portion of the permanent magnet rotor of the first embodiment. [Figure 13] FIG. 1 is a cross-sectional view showing a state in which a die for a gate connection portion of a permanent magnet rotor according to the first embodiment is assembled. [Figure 14] FIG. 1 is a cross-sectional view showing a state in which the mold for the gate connection portion of the permanent magnet rotor according to the first embodiment is removed. [Figure 15] FIG. 1 is a process diagram showing a manufacturing process of a permanent magnet rotor in accordance with a second embodiment. [Figure 16] FIG. 11 is a cross-sectional view showing a disassembled state of a first mold used in the manufacturing process of the second embodiment. [Figure 17] FIG. 11 is a plan view showing a first magnetic field orientation mold of the first mold according to the second embodiment; [Figure 18] FIG. 11 is a cross-sectional view showing a first mold used in the manufacturing process of the second embodiment in an assembled state. [Figure 19] FIG. 11 is a cross-sectional view showing an inner circumference side magnet manufactured using a first mold according to the second embodiment. [Figure 20] FIG. 11 is a cross-sectional view showing a disassembled state of a second mold used in the manufacturing process of the second embodiment. [Figure 21] FIG. 11 is a cross-sectional view showing a second mold used in the manufacturing process of the second embodiment in an assembled state. [Figure 22] FIG. 11 is a cross-sectional view showing an outer magnet manufactured using the second die of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 below in detail with reference to the drawings.

[0011] Embodiment 1 FIG. 1 is a perspective view showing the configuration of a permanent magnet rotor according to the first embodiment. FIG. 2 is a side view showing the configuration of the permanent magnet rotor according to the first embodiment. FIG. 3 is a top view showing the configuration of the permanent magnet rotor according to the first embodiment. FIG. 4 is a cross-sectional view showing the configuration of the permanent magnet rotor according to the first embodiment, taken along the line IV-IV in FIG. 2. FIG. 5 is a perspective view showing the configuration of an inner periphery side magnet of the permanent magnet rotor according to the first embodiment. FIG. 6 is a perspective view showing the configuration of an outer periphery side magnet of the permanent magnet rotor according to the first embodiment. FIG. 7 is a top view showing the positional relationship between the magnetic field-oriented magnetic field lines and the gate connection portion and the weld line in the permanent magnet rotor according to the first embodiment.

[0012] As shown in FIGS. 1 to 6, a permanent magnet rotor 10 has a rotating shaft 1, an inner circumference side magnet 2, and an outer circumference side magnet 3.

[0013] 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 periphery, and a connecting portion 23 that connects the magnetic portion 22 and the shaft holding portion 21. As shown in FIG. 5, one end of the magnetic portion 22 in the axial direction is provided with a plurality of semicircular recesses 24 recessed from the outer edge side to the inner periphery side. In the first embodiment, since the permanent magnet rotor 10 has 10 magnetic poles, five recesses 24, which is half the number of magnetic poles, are provided and are arranged at equal intervals in the circumferential direction. A cross section of the recess 24 cut perpendicular to the axial direction is semicircular. The five recesses 24 have the same shape and are provided only at one end of the magnetic portion 22 in the axial direction.

[0014] The outer magnet 3 has a cylindrical shape. The outer magnet 3 has a plurality of gate connection parts 4 and a plurality of semicircular convex parts 31 provided on the inner side of the gate connection parts 4. The gate connection parts 4 are connected to a gate which is an inlet for resin in an injection molding machine. The semicircular convex parts 31 protruding on the inner side are provided only on one end part in the axial direction of the outer magnet 3, as shown in FIG. 6. The semicircular convex parts 31 fit into a plurality of semicircular concave parts 24 of the inner magnet 2.

[0015] The inner circumference side magnet 2 and the outer circumference side magnet 3 are bonded magnets, and are formed by insert injection molding with a magnetic field orientation within a mold. The magnetic force portion 22 of the inner circumference side magnet 2 and the outer circumference side magnet 3 constitute the magnet portion 11 that functions as a magnet of the permanent magnet rotor 10. The magnetic field orientation of the inner circumference side magnet 2 and the outer circumference side magnet 3 is the same, and the magnetic poles of the inner circumference side magnet 2 and the outer circumference side magnet 3 are identical. The manufacturing method of the inner circumference side magnet 2 and the outer circumference side magnet 3 will be explained in the second embodiment.

[0016] FIG. 7 shows a state in which the permanent magnet rotor 10 is placed in a magnetic field orientation mold. A plurality of teeth 45 of the magnetic field orientation mold are shown around the permanent magnet rotor 10. A magnetic field orientation magnet (not shown) is arranged between the teeth 45, and an outer yoke (not shown) is arranged on the outer periphery of the teeth 45. FIG. 7 shows the concentric magnetic field lines 7 of the permanent magnet rotor 10 formed in the magnet part 11 of the permanent magnet rotor 10 in the magnetic field orientation mold. Note that in FIG. 7, the convex part 31 of the outer periphery magnet 3, the concave part 24 of the inner periphery magnet 2, and the gate connection part 4 are omitted from illustration because they overlap with the concentric magnetic field lines 7 and are difficult to see. For the gate connection part 4, the circular illustration is omitted, and only the reference numeral 4 is shown.

[0017] As shown in FIG. 7, in the first embodiment, the permanent magnet rotor 10 has ten magnetic poles. Since there are ten poles, magnetic field lines 7 are generated in ten locations. The gate connection portions 4 are provided at five equally spaced locations in the middle of the teeth 45. As shown in FIGS. 1 and 3, a protrusion 31 is provided on the inner periphery of the gate connection portion 4. The weld line 6 is located in the middle of the gate connection portion 4. The inter-pole gap 8, which is the middle position between adjacent magnetic poles, is magnetically oriented so as to be in the same position as the weld line 6.

[0018] Next, the semicircular convex portion 31 of the outer magnet 3 and the semicircular concave portion 24 of the inner magnet 2 will be described in detail. The outer magnet 3 is insert injection molded so as to fill the concave portion 24 of the inner magnet 2. In the permanent magnet rotor 10 of the first embodiment, the convex portion 31 of the outer magnet 3 is fitted into the concave portion 24 of the inner magnet 2. This improves the joining strength in the rotational direction between the inner magnet 2 and the outer magnet 3. In addition, since the convex portion 31 and the concave portion 24 are fitted together at the axial ends, the tensile strength in the axial direction between the inner magnet 2 and the outer magnet 3 can be improved.

[0019] The dimensions of the protrusion 31 of the outer magnet 3 and the like will be described with reference to Figs. 8 and 9. Fig. 8 is a partially enlarged plan view for explaining the dimensions of the permanent magnet rotor 10 of the first embodiment. Fig. 9 is a partially enlarged cross-sectional view for explaining the dimensions of the permanent magnet rotor 10 of the first embodiment. The radial thickness of the magnetic force portion 22 of the inner magnet 2 is W1. The radial thickness of the outer magnet 3 is W2. The radial length of the protrusion 31 is W3. W3 represents the radial protrusion length from the inner peripheral surface of the outer magnet 3. The diameter of the gate connection portion 4, which is a circular recess, is W5. The width between the outer circumference of the gate connection portion 4 and the outer circumference of the outer magnet 3 is W6. The width between the inner circumference of the gate connection portion 4 and the tip of the protrusion 31 is W4. The axial height of the protrusion 31 is H1. The depth of the gate connection portion 4, which is a recess, is H2. W2+W3=W4+W5+W6. The thickness W1 of the magnetic portion 22 and the thickness W2 of the outer periphery magnet 3 are approximately the same. That is, W1≈W2.

[0020] It is desirable that the radial height W3 of the protrusion 31 is about half the thickness W1 of the magnetic part 22. In other words, W3 ≈ W1 / 2. This leaves a thickness of about W1 / 2 at the position of the protrusion 31 in the magnetic part 22 of the inner circumference side magnet 2, which is desirable in terms of strength.

[0021] It is desirable that the axial length H1 of the protrusion 31 is approximately the same as the thickness W2 of the outer magnet 3. In other words, H1 ≈ W2. The magnetic resin material that constitutes the outer magnet 3 is injected from the gate connection portion 4 through the protrusion 31. By making the axial height H1 of the protrusion 31 approximately the same as the thickness W2 of the outer magnet 3, pressure loss during resin injection can be suppressed.

[0022] It is desirable that the depth H2 of the gate connection portion 4 is approximately half the axial height H1 of the protrusion 31. In other words, H2≈H1 / 2. This allows the resin material to be injected efficiently and appropriately.

[0023] The diameter W5 of the gate connection portion 4 may be about 1 / 2 to 1 / 4 of W2+W3, which is the radial width of the outer periphery magnet 3 at the position of the protrusion 31. In other words, (W2+W3) / 4≦W5≦(W2+W3) / 2.

[0024] Widths W6 and W4 should be wide enough for the resin to flow sufficiently. To achieve this, they should be about 1 / 2 to 1 / 5 of W2+W3, which is the radial width of the outer magnet 3 at the position of the protrusion 31. In other words, (W2+W3) / 5≦W4≦(W2+W3) / 2, (W2+W3) / 5≦W6≦(W2+W3) / 2.

[0025] Next, the circumferential position of the protrusion 31 will be described with reference to FIG. 10 and FIG. 11. FIG. 10 is a schematic plan view showing the positional relationship between the permanent magnet rotor 10 of the first embodiment and the second magnetic field orientation mold 53. FIG. 11 is a plan view showing the positional relationship between the gate connection portion 4, the magnetic pole center 12, and the weld line 6 in the magnet portion 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 periphery magnet 3 by insert resin molding. The second magnetic field orientation mold 53 has a cylindrical outer periphery yoke 54, a plurality of teeth 55, and a plurality of magnetic field orientation magnets 56. The plurality of teeth 55 extend from the outer periphery yoke 54 toward the inner circumference and are evenly arranged in the circumferential direction. The plurality of magnetic field orientation magnets 56 are arranged between the adjacent teeth 55. The magnetic field orientation magnets 56 are arranged alternately so that the NS pole direction faces the circumferential direction and the N poles and S poles of the adjacent magnetic field orientation magnets 56 face each other. By arranging the magnetic field alignment magnets 56 in this manner, N and S 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.

[0026] The five protrusions 31 of the outer periphery magnet 3 are positioned midway between adjacent tooth portions 55 of the second magnetic field orientation die 53. That is, due to magnetic field orientation by the second magnetic field orientation die 53, a magnetic pole center 12 is formed in a portion of the magnet section 11 facing each tooth portion 55, and therefore each protrusion 31 is positioned midway between adjacent magnetic pole centers 12 in the magnet section 11. The magnetic pole center 12 is the central position of the magnetic pole.

[0027] Since the portion of the protrusion 31 on the outer circumferential magnet 3 has a wide radial width, it is easy to provide the gate connection portion 4 at the portion of the protrusion 31. It is desirable to provide the gate connection portion 4 in the center of the portion of the protrusion 31.

[0028] During injection molding, the magnetic resin material is simultaneously injected from multiple gate connection parts 4 provided at the protrusions 31, so that the magnetic resin material joins together at the intermediate positions between adjacent protrusions 31, forming multiple weld lines 6. In the first embodiment, five weld lines 6 are formed at the intermediate positions between adjacent five gate connection parts 4 in the circumferential direction.

[0029] Here, at the position of the weld line 6, which is the joining portion of the resin material in the injection molding, the joining causes the orientation of the material to be disrupted. When the orientation of the material is disrupted, the magnetic force weakens and the magnetic force varies. The magnetic force of the magnetic pole center 12 is important for the rotation of the rotor. In the first embodiment, the magnetic pole center 12 is formed so that the magnetic pole center 12 and the weld line 6 do not overlap, so that the influence of the orientation variation of the resin joining portion on the magnetic pole center 12 can be suppressed. That is, by arranging the protrusion 31 in the middle of the adjacent magnetic pole centers 12 of the magnet part 11, the influence of the weld line 6 on the magnetic pole center 12 can be suppressed.

[0030] In the above description, an example in which five gate connection parts 4 are provided for a ten-pole magnet has been described, but the present invention is not limited to this combination. FIG. 12 is a plan view showing another positional relationship between the gate connection parts 4, magnetic pole centers 12, and weld lines 6 in the magnet section 11 of the permanent magnet rotor 10 of the first embodiment. For example, as shown in FIG. 12, six gate connection parts 4 may be provided for a twelve-pole magnet. That is, the number of protrusions 31 and gate connection parts 4 is half the number of magnetic poles formed in the magnet section 11, and the protrusions 31 and gate connection parts 4 may be disposed at equal intervals between adjacent magnetic pole centers 12.

[0031] In this way, multiple gate connection parts 4 are installed at equal intervals at 1 / 2 the number of magnetic poles of permanent magnet rotor 10, and the magnetic field orientation of the mold is set so that weld line 6 is located in inter-pole space 8 where magnetic force is zero, thereby minimizing magnetic distortion. Also, because weld line 6 is located in inter-pole space 8 where magnetic force is zero, it is possible to make the surface magnetic flux density distribution of outer magnet 3 closer to an ideal sine wave, thereby reducing vibration noise of the motor.

[0032] FIG. 13 is a cross-sectional view showing a state when the die for the gate connection part 4 of the permanent magnet rotor 10 of the first embodiment is assembled. FIG. 14 is a cross-sectional view showing a state when the die for the gate connection part 4 of the permanent magnet rotor 10 of the first embodiment is removed. The second upper die 51 shown in FIG. 13 is provided with a second gate 59. When the second upper die 51 provided with the second gate 59 is removed, a gate mark 73 that is slightly raised from the die surface 72 is formed at a location corresponding to the second gate 59. If the gate mark 73 is raised above the upper end surface 71 of the magnet part 11, this is undesirable for the product. Therefore, in the first embodiment, the gate connection part 4 recessed in the axial direction is provided, and the second gate 59 is connected to this gate connection part 4, so that even if the gate mark 73 is generated, it is suppressed from rising above the upper end surface 71 in the axial direction.

[0033] The shapes of the recessed portion 24 of the inner magnet 2 and the protruding portion 31 of the outer magnet 3 are not limited to a semicircular shape, and other shapes such as a polygonal shape may be adopted. The overall shape of the inner magnet 2 may also be a simple cylindrical shape.

[0034] As described above, according to the first embodiment, the outer magnet 3 has a plurality of convex portions 31 that protrude to the inner side and fit into the plurality of concave portions 24 of the inner magnet 2, so that the joint strength in the rotation direction between the inner magnet 2 and the outer magnet 3 can be improved. In addition, since the convex portions 31 and the concave portions 24 are fitted at the ends in the axial direction, the tensile strength and pull-out strength in the axial direction between the inner magnet 2 and the outer magnet 3 can be improved. In addition, since the plurality of gate connection portions 4 are disposed at equal intervals at 1 / 2 the number of magnetic poles of the permanent magnet rotor 10, and the magnetic field orientation of the mold is set so that the weld line 6 is located in the inter-pole space 8 where the magnetic force is zero, it is possible to make the surface magnetic flux density distribution of the outer magnet 3 closer to an ideal sine wave, and the vibration noise of the motor can be reduced.

[0035] Embodiment 2 In the second embodiment, a manufacturing method of the permanent magnet rotor 10 will be described. FIG. 15 is a process diagram showing the manufacturing process of the permanent magnet rotor 10 in the second embodiment. FIG. 16 is a cross-sectional view showing a state in which the first mold used in the manufacturing process of the second embodiment is disassembled. FIG. 17 is a plan view showing a first magnetic field orientation mold of the first mold of the second embodiment. FIG. 18 is a cross-sectional view showing a state in which the first mold used in the manufacturing process of the second embodiment is assembled. FIG. 19 is a cross-sectional view showing an inner circumference side magnet 2 manufactured by the first mold of the second embodiment. FIG. 20 is a cross-sectional view showing a state in which the second mold used in the manufacturing process of the second embodiment is disassembled. FIG. 21 is a cross-sectional view showing a state in which the second mold used in the manufacturing process of the second embodiment is assembled. FIG. 22 is a cross-sectional view showing an outer circumference side magnet 3 manufactured by the second mold of the second embodiment.

[0036] As shown in FIG. 22, permanent magnet rotor 10 is manufactured by forming inner circumference side magnets 2 around rotating shaft 1, and forming outer circumference side magnets 3 on the outer periphery of inner circumference side magnets 2.

[0037] First mold placement process (step S1) As shown in FIG. 16, the first mold 40 has a first upper mold 41 having a first gate 49, a first lower mold 42, and a first magnetic field orientation mold 43. As shown in FIG. 17, the first magnetic field orientation mold 43 has a cylindrical outer peripheral yoke 44, a plurality of teeth 45, and a plurality of magnetic field orientation magnets 46. The configuration of the first magnetic field orientation mold 43 is similar to that of the second magnetic field orientation mold 53 described in FIG. 10, and a duplicated description will be omitted. As shown in FIG. 18, the central hole of the first upper mold 41 and the central hole of the first lower mold 42 are inserted into the rotating shaft 1 to form a first space 40a surrounded by the first upper mold 41 and the first lower mold 42. The first magnetic field orientation mold 43 is arranged on the outer periphery of the first upper mold 41 and the first lower mold 42.

[0038] Inner circumference 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 first gate 49 of the first upper die 41. The first magnetic resin material is, for example, an anisotropic ferrite bond magnet material. As a result, as shown in FIG. 19, the anisotropic magnetic resin material is oriented in the direction of the magnetic field lines 7, and an inner magnet 2 magnetized to correspond to the shape of the first space 40a and the direction of the magnetic field lines formed by the magnetic field alignment magnet 46 is formed around the rotation axis 1.

[0039] Second mold placement process (step S3) As shown in FIG. 20, the second mold 50 has a second upper mold 51 having a plurality of second gates 59, a second lower mold 52, and a second magnetic field orientation mold 53 shown in FIG. 10. As shown in FIG. 21, the center hole of the second upper mold 51 and the center hole of the second lower mold 52 are inserted into the inner circumference side magnet 2 holding the rotating shaft 1 to form a second space 50a surrounded by the second upper mold 51 and the second lower mold 52. The second magnetic field orientation mold 53 is disposed on the outer periphery of the second upper mold 51 and the second lower mold 52. The second magnetic field orientation mold 53 has the same shape as the first magnetic field orientation mold 43 and has the same number of magnetic poles. At this time, the rotation direction is positioned by a positioning unit (not shown) so that the magnetic pole center 12 formed in the inner circumference side magnet 2 by the first magnetic field orientation mold 43 and the magnetic pole center 12 formed by the second magnetic field orientation mold 53 coincide with each other. Furthermore, as described in embodiment 1, multiple gate connection parts 4 are installed at equal intervals at 1 / 2 the number of magnetic poles of the permanent magnet rotor 10, and the magnetic field orientation of the second magnetic field orientation mold 53 is set so that the weld line 6 is located between the poles 8 where the magnetic force is zero.

[0040] Outer periphery magnet forming process (step S4) With a magnetic field formed in the second space 50a, a second magnetic resin material is injection molded through the multiple second gates 59 of the second upper die 51. The second magnetic resin material is, for example, an anisotropic rare earth bonded magnet material. As a result, the second magnetic resin material is injected into the second space 50a through the multiple gate connection parts 4. Therefore, as shown in FIG. 22, the anisotropic magnetic resin material is oriented in the direction of the magnetic field lines 7, and the outer periphery magnet 3 magnetized to correspond to the shape of the second space 50a and the direction of the magnetic field lines formed by the magnetic field alignment magnet 56 is formed on the outer periphery of the inner periphery magnet 2, and the permanent magnet rotor 10 is completed.

[0041] According to embodiment 2, multiple gate connection parts 4 are arranged at equal intervals at 1 / 2 the number of magnetic poles of the permanent magnet rotor 10, and the magnetic field orientation of the second magnetic field orientation mold 53 is set so that the weld line 6 is located between the poles 8 where the magnetic force is zero. This makes it possible to make the surface magnetic flux density distribution of the outer magnet 3 into a shape closer to an ideal sine wave, thereby reducing the vibration noise of the motor.

[0042] 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 without departing from the gist of the present disclosure. [Explanation of symbols]

[0043] 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 interpole, 10 permanent magnet rotor, 11 magnet portion, 12 magnetic pole center, 21 shaft holding portion, 22 magnetic field portion, 23 connection portion, 24 concave portion, 31 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 yoke, 45, 55 teeth portion, 46, 56 magnetic field orientation magnet, 49 first gate, 50 second mold, 50a second space, 51 second upper mold, 52 second lower mold, 53 second magnetic field orientation mold, 59 second gate, 71 upper end surface, 72 mold surface, 73 gate mark.

Claims

1. A rotation axis; An inner magnet is a cylindrical bonded magnet having a plurality of recesses on its outer periphery and supporting 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 outer periphery magnet is a plurality of protrusions protruding toward the inner circumference side and fitting into the plurality of recesses of the inner circumference side magnet; The recesses are provided only at one end of the inner magnet in the axial direction, A permanent magnet rotor, characterized in that the multiple protrusions are provided only on one axial end of the outer circumferential magnet.

2. 2. The permanent magnet rotor according to claim 1, wherein the recesses and the protrusions are semicircular.

3. A rotating shaft, An inner magnet is a cylindrical bonded magnet having a plurality of recesses on its outer periphery and supporting 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 outer periphery magnet is a plurality of protrusions protruding toward the inner circumference side and fitting into the plurality of recesses of the inner circumference side magnet; A permanent magnet rotor characterized in that the number of the multiple protrusions is half the number of magnetic poles formed on the inner side magnet and the outer side magnet, and the multiple protrusions are arranged at equal intervals midway between the centers of adjacent magnetic poles.

4. The plurality of recesses are provided at only one end of the inner circumferential magnet in the axial direction, The plurality of protrusions are provided only on one end of the outer circumferential magnet in the axial direction.

4. The permanent magnet rotor according to claim 3.

5. A permanent magnet rotor as described in claim 3 or 4, characterized in that the multiple concave portions and the multiple convex portions are semicircular plate shaped.

6. A permanent magnet rotor as described in any one of claims 1 to 5, characterized in that the outer peripheral magnet has a gate connection portion recessed from an end face of one end of the outer peripheral magnet at a circumferential position where the multiple protrusions are provided.

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