Rotor and motor

Abstract

To provide a rotor having stable magnetic characteristics.SOLUTION: A rotor is a rotor which rotates around a rotation axis. The rotor is provided on a motor. The rotor opposes a stator. The rotor has a plurality of main magnets, a plurality of auxiliary magnets and a holding part. The plurality of main magnets are magnetically oriented in a direction facing the stator. The plurality of main magnets are aligned along the circumferential direction. The plurality of auxiliary magnets are magnetically oriented in the circumferential direction. The auxiliary magnet is arranged between the main magnets. The holding part consists of a resin material. The main magnet and the auxiliary magnet are buried in the holding part. The surface of the main magnet is provided with a first exposed surface exposed from the holding part. The auxiliary magnet is arranged at a deeper side in an opposite side of the stator rather than the first exposed surface.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] An embodiment of the present invention relates to a rotor, and Moo To Regarding. [Background technology]

[0002] There is a known motor in which the magnets of the rotor are arranged in a Halbach array to increase the drive torque. In such a rotor, the positional accuracy of the magnets has a large effect on the magnetic properties of the rotor. However, with conventional technology, it is difficult to increase the positional accuracy of the magnets, and there is a problem that the magnetic properties of the rotor are difficult to stabilize. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2013 / 008284 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a rotor, a motor, and a method for manufacturing a rotor having stable magnetic characteristics. [Means for solving the problem]

[0005] The rotor of the embodiment is a rotor that rotates around a rotation axis. The rotor is provided in a motor. The rotor faces a stator. The rotor has a plurality of main magnets, a plurality of auxiliary magnets, and a holding portion. The plurality of main magnets are magnetically oriented in a direction facing the stator. The plurality of main magnets are aligned along a circumferential direction. The plurality of auxiliary magnets are magnetically oriented in the circumferential direction. The auxiliary magnets are disposed between the main magnets. The holding portion is made of a resin material. The main magnets and auxiliary magnets are embedded in the holding portion. A first exposed surface exposed from the holding portion is provided on a surface of the main magnet. The auxiliary magnet is located on the opposite side of the stator from the first exposed surface. The auxiliary magnet has a surface provided with a second exposed surface that is exposed from the holder. The second exposed surface is partially provided on the auxiliary magnet. [Brief description of the drawings]

[0006] [Figure 1] 1 is a cross-sectional view of a washing machine having a motor according to an embodiment; [Diagram 2] FIG. 2 is a cross-sectional perspective view of a rotor and a stator according to an embodiment; [Diagram 3] FIG. 2 is a schematic partial cross-sectional view of a peripheral wall portion of a rotor according to an embodiment. [Figure 4] FIG. 2 is a schematic diagram of a rotor according to an embodiment, viewed from a stator side. [Diagram 5] FIG. 4 is a partial cross-sectional schematic view of a mold for molding a holding portion of a rotor according to an embodiment. [Figure 6] Schematic diagram showing a homopolar magnetization process according to one embodiment. [Figure 7] Schematic diagram showing a different pole magnetization process according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, a rotor, a motor, and a method of manufacturing a rotor according to the embodiments will be described with reference to the drawings. In the following description, components having the same or similar functions are denoted by the same reference numerals. Furthermore, duplicate descriptions of those components may be omitted.

[0008] FIG. 1 is a cross-sectional view of a washing machine having a motor according to the present embodiment. In the following description, the side of the installation surface of the washing machine, i.e., the vertically lower side, is defined as the lower side of the washing machine, and the opposite side of the installation surface, i.e., the vertically upper side, is defined as the upper side of the washing machine. In addition, left and right are defined based on the direction in which the washing machine is viewed from a user standing in front of the washing machine. In addition, the side closer to the user standing in front of the washing machine as viewed from the washing machine is defined as the "front", and the side farther away is defined as the "rear". In this specification, the "width direction" means the left-right direction in the above definition. In this specification, the "depth direction" means the front-rear direction in the above definition. In the drawings, the +X direction is the right direction, the -X direction is the left direction, the +Y direction is the rear direction, the -Y direction is the front direction, the +Z direction is the up direction, and the -Z direction is the down direction.

[0009] FIG. 1 is a cross-sectional view of a washing machine 1 taken along a line perpendicular to the front-rear direction. Washing machine 1 has, for example, housing 11, top cover 12, water tub 13, rotating tub 14, pulsator 15, and motor 16. Washing machine 1 is a so-called vertical axis type washing machine in which rotation axis O of rotating tub 14 faces vertically. Note that washing machine 1 is not limited to the vertical axis type, and may be a horizontal axis type so-called drum type washing machine in which the rotation axis of the rotating tub is horizontal or inclined downward toward the rear.

[0010] Housing 11 is configured as a rectangular box as a whole from, for example, steel plates. Top cover 12 is made of, for example, synthetic resin, and is provided on the upper part of housing 11. Water tub 13 and spin tub 14 function as a washing tub and a spin tub that accommodate clothes to be washed. Water tub 13 and spin tub 14 are provided inside housing 11. Water tub 13 and spin tub 14 are configured as containers with an open top. Water in water tub 13 flows out from drain port 131 and is drained to the outside via drain valve 132.

[0011] Motor 16 is disposed below water tub 13. Motor 16 is connected to rotating tub 14 and pulsator 15 via a clutch mechanism 17. A rotation axis O of motor 16 coincides with the center of water tub 13.

[0012] The motor 16 of this embodiment is an outer rotor type. The motor 16 has an annular stator 30 arranged around the rotation axis O, and a rotor 20 surrounding the stator 30 from the radially outer side. That is, the motor 16 is provided with the stator 30 and the rotor 20. The stator 30 is fixed to the housing 11 of the washing machine 1. The rotor 20 rotates around the rotation axis O.

[0013] The rotor 20 is a cylindrical member with a bottom, having a peripheral wall portion 22 and a bottom wall portion 21. The peripheral wall portion 22 is cylindrical and centered on the rotation axis O. The peripheral wall portion 22 faces the stator 30 in the radial direction. That is, the rotor 20 faces the stator 30 in the radial direction. The bottom wall portion 21 extends radially inward from the lower end portion of the peripheral wall portion 22. The bottom wall portion 21 is a disk shape that extends along a plane perpendicular to the rotation axis O. The rotor 20 is connected to the clutch mechanism 17 at the bottom wall portion 21.

[0014] Clutch mechanism 17 selectively transmits the rotation of motor 16 to spin tub 14 and pulsator 15. During washing and rinsing, clutch mechanism 17 transmits the driving force of motor 16 to pulsator 15 to directly rotate pulsator 15 in forward and reverse directions at a low speed. On the other hand, during spin-drying and other operations, clutch mechanism 17 transmits the driving force of motor 16 to spin tub 14 to rotate spin tub 14 in one direction at high speed.

[0015] Fig. 2 is a cross-sectional perspective view of the rotor 20 and the stator 30. Note that a holding portion 70, which will be described later, is omitted in Fig. 2. Also, Fig. 2 shows a schematic view of the shape of the magnets.

[0016] Fig. 3 is a partial cross-sectional schematic diagram of the peripheral wall portion 22 of the rotor 20. Fig. 3 is a cross-sectional view along a cross section perpendicular to the rotation axis O, in which a circumferential direction C centered on the rotation axis O is displayed as a straight line extending in the left-right direction of the page, and a radial direction R centered on the rotation axis O is displayed in the up-down direction of the page. The upper side of Fig. 3 corresponds to the radial inner side centered on the rotation axis O, and the lower side of Fig. 3 corresponds to the radial outer side centered on the rotation axis O. Therefore, in Fig. 3, the stator 30 is disposed on the upper side of the rotor 20 on the page.

[0017] In the following description, the direction in which the stator 30 is arranged relative to the rotor 20 (the radially inner side in this embodiment) is referred to as the stator side R1, and the direction opposite the stator 30 in the radial direction (the radially outer side in this embodiment) is referred to as the anti-stator side R2.

[0018] 2, the stator 30 has a stator core 31, a coil 39, and an insulator (not shown). The stator core 31 has an annular core back portion 32 centered on the rotation axis O, and a plurality of teeth portions 33 extending radially outward from the core back portion 32. The plurality of teeth portions 33 are aligned along the circumferential direction C. The coil 39 is formed by winding a conducting wire around the teeth portions 33 via the insulator.

[0019] The rotor 20 has a plurality of main magnets 80, a plurality of auxiliary magnets 90, a frame 60, and a holding portion 70 (omitted in FIG. 2, see FIG. 3) that fixes these together.

[0020] As shown in FIG. 2, the frame 60 has a disk portion 61 and a cylindrical portion 62. The disk portion 61 is disk-shaped and centered on the rotation axis O. The disk portion 61 constitutes the bottom wall portion 21 of the rotor 20. The cylindrical portion 62 extends upward from the outer edge of the disk portion 61. The cylindrical portion 62 is cylindrical and centered on the rotation axis O. The multiple main magnets 80 and the multiple auxiliary magnets 90 are aligned in the circumferential direction C along the inner surface of the cylindrical portion 62.

[0021] The main magnet 80 and the auxiliary magnet 90 each have a uniform cross section and extend in a columnar shape along the axial direction of the rotation axis O. The upper surfaces of the main magnet 80 and the auxiliary magnet 90 form approximately the same plane. Similarly, the lower surfaces of the main magnet 80 and the auxiliary magnet 90 form approximately the same plane. The lower surfaces of the main magnet 80 and the auxiliary magnet 90 face and contact the upper surface of the disk portion 61 of the frame 60.

[0022] In this embodiment, the primary magnets 80 and the auxiliary magnets 90 are ferrite magnets, however, the primary magnets 80 and the auxiliary magnets 90 may be other types of magnets (e.g., neodymium magnets).

[0023] As shown in Fig. 3, the main magnets 80 and the auxiliary magnets 90 are alternately arranged along the circumferential direction C. The main magnets 80 and the auxiliary magnets 90 are magnetically oriented in the radial direction R and the circumferential direction C, respectively. That is, the main magnets 80 and the auxiliary magnets 90 are arranged in a Halbach array. Note that in Fig. 3, the arrows shown on each magnet indicate the magnetic orientation of that magnet.

[0024] The main magnets 80 are magnets that are magnetically oriented in the radial direction R. That is, the direction of the internal magnetic flux of the main magnets 80 is the radial direction R. The magnetic poles of the multiple main magnets 80 aligned in the circumferential direction C are alternately inverted. Therefore, the magnetic poles (north or south poles) facing one radial side of adjacent main magnets 80 in the circumferential direction C are different from each other.

[0025] The main magnet 80 has a first opposing surface 81 facing the stator side R1 and facing the stator 30, a first outer surface 82 facing the anti-stator side R2, and a pair of first circumferential end surfaces 83 facing both sides in the circumferential direction. The thickness dimension of the main magnet 80 in the radial direction R is greatest at the circumferential center and decreases toward both sides in the circumferential direction.

[0026] The first opposing surface 81 is a curved surface that protrudes outward in the radial direction R. The radius of curvature of the first opposing surface 81 in a cross section perpendicular to the rotation axis O is sufficiently smaller than the distance from the rotation axis O to the first opposing surface 81. The first opposing surface 81 approaches the anti-stator side R2 from the center toward both sides in the circumferential direction C.

[0027] The first outer surface 82 is a flat surface or a gently curved surface with a constant distance to the rotation axis O. The first outer surface 82 faces the cylindrical portion 62 of the frame 60 with a slight gap therebetween.

[0028] The first circumferential end surfaces 83 are flat surfaces. The pair of first circumferential end surfaces 83 each extend along the radial direction R. The first circumferential end surfaces 83 may be inclined with respect to the radial direction R in a cross section perpendicular to the rotation axis O.

[0029] The auxiliary magnets 90 are magnets that are magnetically oriented in the circumferential direction C. That is, the direction of the internal magnetic flux of the auxiliary magnets 90 is the circumferential direction C. The magnetic pole orientations of the multiple auxiliary magnets 90 lined up in the circumferential direction C are alternately reversed. Therefore, the magnetic poles (north pole or south pole) facing one circumferential side of the auxiliary magnets 90 adjacent to each other in the circumferential direction C are different from each other.

[0030] The auxiliary magnet 90 has a second opposing surface 91 facing the stator side R1 and opposing the stator 30, a second outer surface 92 facing the anti-stator side R2, and a pair of second circumferential end surfaces 93 facing both sides in the circumferential direction.

[0031] In a cross section perpendicular to the rotation axis O, the auxiliary magnet 90 of this embodiment is, for example, rectangular. The thickness dimension of the auxiliary magnet 90 along the radial direction R is smaller than the thickness dimension of the main magnet 80 along the radial direction R. In addition, the dimension of the auxiliary magnet 90 along the circumferential direction C is smaller than the dimension of the main magnet 80 along the circumferential direction C.

[0032] The second opposing surface 91 is a flat surface or a gently curved surface with a constant distance to the rotation axis O. Similarly, the second outer surface 92 is a flat surface or a gently curved surface with a constant distance to the rotation axis O. Therefore, the thickness dimension of the auxiliary magnet 90 along the radial direction R is uniform. The second opposing surface 91 is located on the anti-stator side R2 of the first opposing surface 81. In addition, the second outer surface 92 is located on the stator side R1 of the first outer surface 82. The second outer surface 92 faces the cylindrical portion 62 of the frame 60 via a gap.

[0033] The second circumferential end surfaces 93 are flat surfaces. Each of the pair of second circumferential end surfaces 93 extends along the radial direction R. The second circumferential end surfaces 93 may be inclined with respect to the radial direction R in a cross section perpendicular to the rotation axis O.

[0034] The second circumferential end face 93 of the auxiliary magnet 90 faces the first circumferential end face 83 of the main magnet 80. The second circumferential end face 93 and the first circumferential end face 83 are parallel to each other. It is preferable that the second circumferential end face 93 be in surface contact with the first circumferential end face 83. However, a small gap may be provided between the second circumferential end face 93 and the first circumferential end face 83.

[0035] The holding portion 70 is made of a resin material. A plurality of main magnets 80 and a plurality of auxiliary magnets 90 are embedded in the holding portion 70. In this way, the holding portion 70 holds the plurality of main magnets 80 and the plurality of auxiliary magnets 90. The holding portion 70 has a stator facing surface 71 that faces the stator side R1 and faces the stator 30.

[0036] A first opposing surface 81 of the main magnet 80 protrudes toward the stator side R1 relative to the stator opposing surface 71 of the holding portion 70. Therefore, a part of the first opposing surface 81 is exposed from the holding portion 70 to the stator side R1. The main magnet 80 is exposed from the holding portion 70 at a first exposed surface 86 located in a region in the circumferential center of the first opposing surface 81. The main magnet 80 is embedded in the holding portion 70 at a first embedded surface 87 located in a region on both ends in the circumferential direction of the first opposing surface 81. The first embedded surfaces 87 are located on both sides in the circumferential direction of the first exposed surface 86.

[0037] A first recess 72 exposing the second opposing surface 91 of the auxiliary magnet 90 is provided in the stator opposing surface 71 of the holding portion 70. The first recess 72 is located in the circumferential center of the second opposing surface 91. That is, a second exposed surface 96 exposed to the stator side R1 is provided in the circumferential center of the second opposing surface 91. Furthermore, a second embedded surface 97 embedded in the holding portion 70 is provided in the area of ​​the second opposing surface 91 excluding the second exposed surface 96.

[0038] According to this embodiment, a first exposed surface 86 exposed from the holding portion 70 is provided on the surface of the main magnet 80. The first exposed surface 86 of the main magnet 80 contacts the inner surface of the mold for molding the holding portion 70. When multiple magnets (main magnets 80 and auxiliary magnets 90) are arranged in a Halbach array, as in the rotor 20 of this embodiment, the positional accuracy of the main magnet 80 has a significant effect on the output performance of the motor 16. According to this embodiment, by bringing the main magnet 80 into contact with the inner surface of the mold for molding the holding portion 70, it is possible to improve the positional accuracy of the main magnet 80 after the holding portion 70 is molded.

[0039] According to this embodiment, the first exposed surface 86 faces the radial direction R. The main magnet 80 is positioned in the radial direction R within the mold by contact of the first exposed surface 86 with the mold. The accuracy of the distance between the main magnet 80 and the stator 30 has a particularly large effect on the output performance of the motor 16. According to this embodiment, the distance in the radial direction R between the multiple main magnets 80 and the stator 30 can be matched with high accuracy, and the output performance of the motor 16 can be improved.

[0040] According to the present embodiment, the first exposed surface 86 is located on the first opposing surface 81 that faces the stator 30. This makes it possible to suppress the retaining portion 70 from interfering with the flow of magnetic flux between the first exposed surface 86 and the stator 30, thereby improving the output performance of the motor 16.

[0041] According to this embodiment, the first opposing surface 81 of the main magnet 80 has first embedded surfaces 87 embedded in the retaining portion 70 provided on both circumferential sides of the first exposed surface 86. When the motor 16 is driven, a large force is applied to the main magnet 80 toward the stator side R1. The retaining portion 70 suppresses movement of the main magnet 80 toward the stator side R1 at the first embedded surface 87 of the main magnet 80. According to this embodiment, the main magnet 80 is firmly held by the retaining portion 70, and movement of the main magnet 80 toward the stator side R1 is more reliably suppressed.

[0042] According to this embodiment, a second exposed surface 96 exposed from the holding portion 70 is provided on the surface of the auxiliary magnet 90. The auxiliary magnet 90 contacts the inner surface of the mold that molds the holding portion 70 at the second exposed surface 96. According to this embodiment, by bringing the auxiliary magnet 90 into contact with the inner surface of the mold that molds the holding portion 70, it is possible to improve the positional accuracy of the auxiliary magnet 90 after the holding portion 70 is molded.

[0043] According to the present embodiment, the second exposed surface 96 faces the radial direction R. Therefore, the auxiliary magnet 90 is positioned in the radial direction R within the die by the contact of the second exposed surface 96 with the die. In the rotor 20 in the Halbach array, if the auxiliary magnet 90 gets too close to the stator 30, demagnetization of the auxiliary magnet 90 during driving becomes significant. According to the present embodiment, the distance between the auxiliary magnet 90 and the stator 30 in the radial direction R can be reliably increased, and demagnetization of the auxiliary magnet 90 can be suppressed.

[0044] According to this embodiment, the second opposing surface 91 of the auxiliary magnet 90 is provided with a second embedded surface 97 that is embedded by the holding portion 70. This allows the auxiliary magnet 90 to be firmly held by the holding portion 70, and movement of the auxiliary magnet 90 toward the stator side R1 is more reliably suppressed.

[0045] FIG. 4 is a schematic diagram of the rotor 20 as viewed from the stator side R1. The first exposed surface 86 is provided over the entire axial length of the main magnet 80. On the other hand, the second exposed surface 96 is provided partially in the axial direction of the auxiliary magnet 90.

[0046] According to this embodiment, the first exposed surface 86 of the main magnet 80 is provided over the entire axial length. A wide area of ​​the first exposed surface 86 is ensured, and the flow of magnetic flux between the main magnet 80 and the stator 30 can be made smoother. This further increases the output of the motor 16. In addition, the flow of magnetic flux between the main magnet 80 and the stator 30 becomes uniform in the axial direction. This increases the rotation efficiency of the rotor 20.

[0047] On the other hand, according to this embodiment, the second exposed surface 96 of the auxiliary magnet 90 is located only near the upper end of the second opposing surface 91. As described above, the second exposed surface 96 is exposed in the radial direction R as the bottom surface of the first recess 72 of the holding portion 70. The first recess 72 opens to the stator side R1 and also opens upward. By providing the second exposed surface 96 only on a portion of the second opposing surface in the axial direction, the second buried surface 97 covered by the holding portion 70 is ensured to be wide. For this reason, the holding force of the auxiliary magnet 90 by the holding portion 70 is enhanced. Note that a plurality of second exposed surfaces 96 may be provided on the second opposing surface 91.

[0048] As shown in Fig. 3, the retaining portion 70 is provided with a plurality of second recesses (recesses) 74. The plurality of second recesses 74 are arranged side by side along the circumferential direction C. Two second recesses 74 are arranged on the anti-stator side R2 of one auxiliary magnet 90. The second recesses 74 are located near the upper ends of the main magnet 80 and the auxiliary magnet 90, and open upward (see Fig. 4). The second recesses 74 are formed by a part of a mold that molds the retaining portion 70.

[0049] A third exposed surface 88 exposed in the second recess 74 is provided on the first circumferential end surface 83 of the main magnet 80. The third exposed surface 88 is provided on each of the pair of first circumferential end surfaces 83 of the main magnet 80. That is, a pair of third exposed surfaces 88 facing both circumferential sides is provided on the surface of the main magnet 80. The third exposed surface 88 is provided in an area of ​​the first circumferential end surface 83 on the opposite side to the stator.

[0050] According to this embodiment, one main magnet 80 is exposed at a pair of third exposed surfaces 88 facing both sides in the circumferential direction. The main magnet 80 is sandwiched from both sides in the circumferential direction by parts of a mold in a mold that molds the holding portion 70. This allows the main magnet 80 and the auxiliary magnet 90 arranged between the pair of main magnets 80 in the mold to be positioned in the circumferential direction. Therefore, it is possible to prevent the multiple main magnets 80 and auxiliary magnets 90 from being biased to one side in the circumferential direction. In other words, it is possible to arrange the multiple main magnets 80 and auxiliary magnets 90 lined up in the circumferential direction at regular intervals.

[0051] The second outer surface 92 of the auxiliary magnet 90 is provided with a fourth exposed surface 98 exposed in the second recess 74. As described above, two second recesses 74 are provided on the anti-stator side R2 of the auxiliary magnet 90. Therefore, the second outer surface 92 is provided with two fourth exposed surfaces 98 aligned in the circumferential direction C.

[0052] The second outer surface 92 of the auxiliary magnet 90 is provided with a fourth exposed surface 98 exposed in the second recess 74. As described above, two second recesses 74 are provided on the anti-stator side R2 of the auxiliary magnet 90. Therefore, the second outer surface 92 is provided with two fourth exposed surfaces 98 aligned in the circumferential direction C.

[0053] According to this embodiment, exposed surfaces (second exposed surface 96 and fourth exposed surface 98) are provided on the surfaces of the auxiliary magnet 90 facing both sides in the radial direction R (second opposing surface 91 and second outer surface 92). The auxiliary magnet 90 is sandwiched between parts of the mold at the second exposed surface 96 and the fourth exposed surface 98 facing both sides in the radial direction R. This makes it possible to more reliably improve the positional accuracy of the auxiliary magnet 90 in the radial direction R after the holding portion 70 is molded.

[0054] In this embodiment, the third exposed surface and the fourth exposed surface are exposed inside the second recess 74. Therefore, the second recess 74 can determine the circumferential position of the main magnet 80 and the radial position of the auxiliary magnet 90.

[0055] Next, a method for manufacturing the rotor 20 will be described. The manufacturing method of the rotor 20 includes a housing step, a resin molding step, and a magnetizing step. The housing step, the resin molding step, and the magnetizing step are performed in this order. Each step will now be described in detail.

[0056] FIG. 5 is a schematic partial cross-sectional view of a die 10 for forming the holding portion 70 of the rotor 20. As shown in FIG. The mold 10 has a male mold and a female mold that can approach and separate from each other, for example, in the axial direction. At the joint between the male mold and the female mold, a gap G is provided that houses the frame 60, the first magnetic member 80A, and the second magnetic member 90A and is filled with molten resin. The gap G is an annular space that extends along the circumferential direction C of the rotation axis O.

[0057] In the accommodation step, an operator accommodates the frame 60, the first magnetic member 80A, and the second magnetic member 90A in the gap G in the mold 10. The first magnetic member 80A is an unmagnetized main magnet 80. Similarly, the second magnetic member 90A is an unmagnetized auxiliary magnet 90. The first magnetic member 80A and the second magnetic member 90A are alternately arranged in an annular shape in the gap G in the circumferential direction C of the rotation axis O.

[0058] The inner surface of the die 10 is provided with a first die surface 8 and a second die surface 9 which face each other in the radial direction R with a gap G therebetween. The first die surface 8 is a surface facing the anti-stator side R2. The second die surface 9 is a surface facing the stator side R1. The first die surface 8 and the second die surface 9 are each a cylindrical surface centered on the rotation axis O. The second die surface 9 comes into contact with a cylindrical portion 62 of the frame 60. This positions the frame 60 within the die 10.

[0059] The first die surface 8 is provided with a plurality of die recesses 8a and a plurality of first die protrusions 8b. The die recesses 8a and the first die protrusions 8b are arranged alternately along the circumferential direction C. The die recesses 8a open to the anti-stator side R2. The tip surface of the first die protrusions 8b is a flat surface facing the anti-stator side R2.

[0060] Inside the mold 10, the first magnetic member 80A contacts the inner surface of the mold recess 8a. Also inside the mold 10, the second magnetic member 90A contacts the tip surface of the first mold protrusion 8b. The mold recess 8a is provided over the entire axial length of the gap G, and the first mold protrusion 8b is provided at the upper end of the gap G.

[0061] At the upper end of the gap G, a plurality of second die protrusions 8c are provided, which protrude downward from the inner surface of the die 10 facing downward. The plurality of second die protrusions 8c are aligned along the circumferential direction C of the rotation axis O. The second die protrusions 8c are located on the anti-stator side R2 of the second magnetic member 90A. The second die protrusions 8c are also located on the stator side R1 of the cylindrical portion 62 of the frame 60.

[0062] The first magnetic member 80A is sandwiched between the pair of second die protrusions 8c from both sides in the circumferential direction C. As a result, the first magnetic member 80A is positioned in the circumferential direction C within the die 10.

[0063] The second magnetic member 90A is sandwiched between the first mold protrusion 8b and the pair of second mold protrusions 8c in the radial direction R. As a result, the second magnetic member 90A is positioned in the radial direction R within the mold 10.

[0064] The resin molding process is a process of resin-molding the first magnetic member 80A and the second magnetic member 90A by filling the inside of the die 10 with molten resin. After the molten resin has solidified, an operator removes the molded rotor 20 from the die 10.

[0065] The mold 10 is provided with a gate 10g for filling the molten resin into the gap G. The gate 10g is located at the upper end of the gap G and opens into the gap G. The gate 10g is disposed in the gap G biased toward the anti-stator side R2.

[0066] According to this embodiment, the gate 10g is arranged biased toward the anti-stator side R2, so that the molten resin injected from the gate 10g into the gap G preferentially flows around the anti-stator side R2 region of the gap G. The first magnetic member 80A and the second magnetic member 90A are pressed against the stator side R1 by the injection pressure of the molten resin. That is, in the resin molding process, the first magnetic member 80A and the second magnetic member 90A are pressed against the surface of the die 10 facing the radial direction R. As a result, the first magnetic member 80A and the second magnetic member 90A are positioned with high accuracy with respect to the first die surface 8 of the die 10.

[0067] 3, a gate mark 70g is formed in a portion corresponding to the gate 10g of the holding part 70. The gate mark 70g is disposed biased toward the anti-stator side R2 (the opposite side to the stator) with respect to the center in the radial direction R of the holding part 70.

[0068] The magnetizing step is a step of magnetizing the first magnetic member 80A and the second magnetic member 90A. The magnetizing step includes a same-polarity magnetizing step and a different-polarity magnetizing step.

[0069] Fig. 6 is a schematic diagram showing a same-polarity magnetization process, and Fig. 7 is a schematic diagram showing a different-polarity magnetization process. The same polarity magnetization step is a step of magnetizing the second magnetic member 90A to set the magnetic orientation of the second magnetic member 90A in the circumferential direction C. The second magnetic member 90A is magnetized by the same polarity magnetization step to become a permanent magnet (auxiliary magnet 90). The different pole magnetizing step is a step of magnetizing the first magnetic member 80A to set the magnetic orientation of the first magnetic member 80A in the radial direction R. The first magnetic member 80A is magnetized by the different pole magnetizing step to become a permanent magnet (main magnet 80).

[0070] The same-polarity magnetization process and the different-polarity magnetization process are performed by a magnetization device 4. The magnetization device 4 has four magnetization yokes (a first magnetization yoke 40A, a second magnetization yoke 40B, a third magnetization yoke 40C, and a fourth magnetization yoke 40D). The four magnetization yokes are connected to a magnetization power source (not shown). The magnetization device of this embodiment uses four magnetization yokes. However, the magnetization device may have, for example, a number of magnetization yokes that can magnetize all of the first magnetic members 80A and all of the second magnetic members 90A simultaneously.

[0071] The first magnetizing yoke 40A and the second magnetizing yoke 40B are disposed facing each other in the radial direction R. The first magnetizing yoke 40A and the second magnetizing yoke 40B are disposed on both sides in the plate thickness direction of one first magnetic member 80A. The first magnetizing yoke 40A is disposed on the outer side in the radial direction R, and the second magnetizing yoke 40B is disposed on the inner side in the radial direction R.

[0072] The third magnetizing yoke 40C and the fourth magnetizing yoke 40D are disposed facing each other in the radial direction R. The third magnetizing yoke 40C and the fourth magnetizing yoke 40D are disposed on both sides in the plate thickness direction of the first magnetic member 80A adjacent to the first magnetic member 80A sandwiched between the first magnetizing yoke 40A and the second magnetizing yoke 40B. The third magnetizing yoke 40C is disposed on the outside in the radial direction R, and the fourth magnetizing yoke 40D is disposed on the inside in the radial direction R.

[0073] As shown in FIG. 6, in the homopolar magnetization process, a homopolar magnetic field is generated in the first magnetizing yoke 40A and the second magnetizing yoke 40B that face each other. Furthermore, a homopolar magnetic field is generated in the third magnetizing yoke 40C and the fourth magnetizing yoke 40D that face each other. At this time, the magnetic field generated in the third magnetizing yoke 40C and the fourth magnetizing yoke 40D has a polarity different from that of the magnetic field generated in the first magnetizing yoke 40A and the second magnetizing yoke 40B. In the homopolar magnetization process, the second magnetic member 90A is magnetized in the circumferential direction C. In addition, when the second magnetic member 90A is magnetized in the opposite direction in the circumferential direction C, the magnetic field generated in the four magnetizing yokes 40A, 40B, 40C, and 40D may be made to have a polarity opposite to that described above.

[0074] As shown in Fig. 7, in the different pole magnetization process, a magnetic field of different poles is generated in the opposing first magnetization yoke 40A and the second magnetization yoke 40B, so that the sandwiched first magnetic member 80A is magnetized in one direction (opposite magnetization). At the same time, a magnetic field of different poles is generated in the opposing third magnetization yoke 40C and the fourth magnetization yoke 40D, so that the sandwiched first magnetic member 80A is magnetized in the other direction (opposite magnetization). At this time, the direction of the magnetic field between the third magnetization yoke 40C and the fourth magnetization yoke 40D is opposite to the direction of the magnetic field between the first magnetization yoke 40A and the second magnetization yoke 40B. In the different pole magnetization process, all the first magnetic members 80A are magnetized sequentially.

[0075] In the magnetization process, the same-polarity magnetization process and the different-polarity magnetization process are alternately repeated in this order. Completion of the magnetization process completes the rotor 20. The manufactured rotor 20 is combined with a stator 30 that is manufactured separately.

[0076] According to the manufacturing method of the rotor 20 of this embodiment, both the first magnetic member 80A and the second magnetic member 90A are unmagnetized in the magnet housing step, so that the first magnetic member 80A and the second magnetic member 90A can be disposed close to each other in the housing step.

[0077] According to this embodiment, the main magnet 80 and the auxiliary magnet 90 are resin-molded in a resin molding process and fixed by the holding portion 70. The holding portion 70 prevents the main magnet 80 and the auxiliary magnet 90 from repelling each other and moving away from each other. This increases the degree of freedom in arranging the main magnet 80 and the auxiliary magnet 90. In this embodiment, the main magnet 80 and the auxiliary magnet 90 are arranged at high density. This increases the magnetic force of the rotor 20 and improves the torque of the motor 16.

[0078] According to the manufacturing method of the rotor 20 of this embodiment, the main magnet 80 is magnetized by opposing magnetization. This suppresses the generation of leakage flux in the magnetization process (different pole magnetization process) of the main magnet 80, and the magnetization rate of the main magnet 80 can be increased. Furthermore, according to the manufacturing method of the rotor 20 of this embodiment, the different pole magnetization process is carried out after the same pole magnetization process. This suppresses demagnetization of the main magnet 80 in the magnetization process of the auxiliary magnet 90.

[0079] In this embodiment, an outer rotor type motor 16 has been described. However, the above configuration may also be adopted for an inner rotor type motor.

[0080] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0081] 10... mold, 10g... gate, 16... motor, 20... rotor, 30... stator, 70... holding portion, 70g... gate mark, 74... second recess (recess), 80... main magnet, 80A... first magnetic member, 81... first opposing surface, 86... first exposed surface, 87... first embedded surface (embedded surface), 88... third exposed surface, 90... auxiliary magnet, 90A... second magnetic member, 91... second opposing surface, 96... second exposed surface, 98... fourth exposed surface, C... circumferential direction, O... rotation axis, R... radial direction

Claims

1. A rotor is provided in a motor and faces a stator. The rotor rotates about a rotation axis. A plurality of main magnets arranged along a circumferential direction and magnetically oriented in a direction facing the stator; A plurality of auxiliary magnets arranged between the main magnets and oriented in a circumferential direction; a holding portion made of a resin material and into which the main magnet and the auxiliary magnet are embedded, a first exposed surface exposed from the holding portion is provided on a surface of the main magnet; the auxiliary magnet is located on the opposite side of the stator from the first exposed surface, A second exposed surface is provided on a surface of the auxiliary magnet and is exposed from the holding portion. The second exposed surface is partially provided on the auxiliary magnet. Rotor.

2. the main magnet has a first opposing surface facing the stator, The first exposed surface is located on the first opposing surface. The rotor of claim 1 .

3. the auxiliary magnet has a second opposing surface facing the stator, The second exposed surface is located on the second opposing surface. The rotor of claim 1 .

4. The holding portion is provided with a gate mark, The gate mark is disposed on the holding portion so as to be biased toward the opposite side of the stator. A rotor according to any one of claims 1 to 3.

5. The first exposed surface is provided at a center of the first opposing surface, and embedded surfaces that are embedded in the holding portion are provided on both sides of the first exposed surface. A rotor according to claim 2.

6. The rotor according to claim 1 , wherein the first exposed surface is provided over an entire axial length of the main magnet.

7. A rotor according to any one of claims 1 to 6; The stator, Motor.

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