CN115912819A - Method for manufacturing magnetic pole and method for manufacturing rotor - Google Patents

Abstract

The invention provides a method for manufacturing a magnetic pole and a method for manufacturing a rotor. The magnetic pole is provided on the outer periphery of the rotor that rotates around the center axis, and has a magnet portion and an outer core portion disposed radially outside the magnet portion. The method for manufacturing the magnetic pole comprises the following steps: an outer iron core molding step of molding an outer iron core part; an outer core fixing step of fixing the outer core portion to a surface of the magnet portion facing radially outward; and an outer periphery processing step of processing the surface of the outer core portion facing the radial outer side with reference to the surface of the magnet portion facing the radial inner side.

Description

Method for manufacturing magnetic pole and method for manufacturing rotor

Technical Field

The present invention relates to a method for manufacturing a magnetic pole and a method for manufacturing a rotor.

Background

Conventionally, an IPM (Interior Permanent Magnet) type rotor is known in which a Magnet is embedded in a rotor core. As one of such rotors, a rotor is known in which a magnet is attached to an outer peripheral surface of an inner core, and an outer core is attached to an outer peripheral surface of the magnet (patent document 1). By forming the inner core and the outer core as separate members, magnetic flux is less likely to pass between the inner core and the outer core, and so-called leakage flux can be suppressed.

Patent document 1: japanese patent laid-open No. 2021-57967

In the case where the inner core and the outer core are separate members as in the conventional structure, there are problems as follows: when the inner core, the magnet, and the outer core are fixed to each other, the tolerances of the respective components are accumulated, and it is difficult to ensure the dimensional accuracy of the outer shape of the rotor.

Disclosure of Invention

In view of the above circumstances, an object of the present invention is to provide a method of manufacturing a magnetic pole capable of stabilizing the outer diameter dimension of a rotor.

One aspect of the present invention is a method of manufacturing a magnetic pole that is provided on an outer periphery of a rotor that rotates around a central axis, and that has a magnet portion and an outer core portion disposed radially outward of the magnet portion. The method for manufacturing the magnetic pole comprises the following steps: an outer iron core molding step of molding the outer iron core portion; an outer core fixing step of fixing the outer core portion to a radially outward surface of the magnet portion; and an outer periphery machining step of machining a surface of the outer core portion facing radially outward with reference to a surface of the magnet portion facing radially inward.

According to the method for manufacturing a magnetic pole of one embodiment of the present invention, a rotor having a stable outer diameter dimension can be provided.

Drawings

Fig. 1 is a cross-sectional view in section along a central axis of a motor of an embodiment.

Fig. 2 is a perspective view of a rotor according to an embodiment.

FIG. 3 is a partial cross-sectional view of one embodiment of a rotor.

Fig. 4 is a flowchart illustrating a method of manufacturing a rotor according to an embodiment.

Fig. 5 is a schematic view showing an outer peripheral processing step of one embodiment.

Fig. 6 is a flowchart of an outer core molding process according to an embodiment.

Fig. 7 is a flowchart of an outer core molding process according to a modification.

Fig. 8 is a flowchart of a magnetic pole fixing process according to an embodiment.

Fig. 9 is a partial sectional view of a mold for molding the cage according to the embodiment.

Fig. 10 is a flowchart of a magnetic pole fixing step of a modification.

Fig. 11 is a schematic diagram illustrating a magnetic pole fixing step of a modification.

Fig. 12 is a diagram showing an example of the outer shape of the outer core portion 24 of the embodiment.

Fig. 13 is a view showing an example 1 of an outer core portion manufactured by a conventional manufacturing method.

Fig. 14 is a view showing a 2 nd example of an outer core portion manufactured by a conventional manufacturing method.

Description of the reference symbols

20. 120: a rotor; 22: a rotor core; 23: a magnet section; 23a: an inner magnet surface (a surface facing radially inward); 23b: a magnet outer side surface (a surface facing the radial outer side); 24: an outer iron core portion; 24a: an iron core inner side surface (a surface facing the radially inner side); 24b: an iron core outer side surface (a surface facing a radial outer side); 28: a magnetic pole; 40. 140: a holder; 149: a magnetic pole receiving part; j: a central axis; s120 and S120A: forming an outer iron core; s121: a laminating step; s122: a magnetic member fixing step; s130: fixing the outer iron core; s140: a peripheral processing step; s300, S300A: fixing the magnetic pole; s320: a molding process; S122A: a cutting step; S310A: a cage forming process; S320A: a magnetic pole housing step; S330A: and (5) a cover mounting procedure.

Detailed Description

In the following description, the axial direction of the center axis J, i.e., the direction parallel to the vertical direction, is simply referred to as the "axial direction", the radial direction about the center axis J is simply referred to as the "radial direction", and the circumferential direction about the center axis J is simply referred to as the "circumferential direction". In the present embodiment, the lower side (-Z) corresponds to the other axial side, and the upper side (+ Z) corresponds to the one axial side. The vertical direction, the upper side, and the lower side are only names for describing the relative positional relationship of the respective parts, and the actual arrangement relationship and the like may be an arrangement relationship other than the arrangement relationship and the like indicated by these names.

Fig. 1 is a cross-sectional schematic view in a cross section along the central axis J of the motor 1.

The motor 1 of the present embodiment includes a rotor 20, a stator 30, a plurality of bearings 15, and a housing 11 that houses these components. The bearing 15 rotatably supports a shaft 21 of the rotor 20. The bearing 15 is held by the housing 11.

The stator 30 has an annular shape centered on the central axis J. The rotor 20 is disposed radially inward of the stator 30. The stator 30 is radially opposed to the rotor 20.

The stator 30 has a stator core 31, an insulator 32, and a plurality of coils 33. The stator core 31 is formed of a plurality of magnetic members stacked in the axial direction.

The stator core 31 has a substantially annular core back 31c and a plurality of teeth 31b. In the present embodiment, the core back 31c has an annular shape centered on the central axis J. The teeth 31b extend radially inward from the radially inner surface of the core back 31 c. The outer peripheral surface of the core back 31c is fixed to the inner peripheral surface of the peripheral wall of the housing 11. The plurality of teeth 31b are arranged on the radially inner surface of the core back 31c at intervals in the circumferential direction. In the present embodiment, the plurality of teeth 31b are arranged at equal intervals in the circumferential direction.

The insulator 32 is attached to the stator core 31. The insulator 32 has a portion covering the teeth 31b. The material of the insulating member 32 is, for example, an insulating material such as resin.

The coil 33 is attached to the stator core 31. The plurality of coils 33 are attached to the stator core 31 via the insulator 32. The plurality of coils 33 are formed by winding a conductive wire around each tooth 31b via an insulator 32.

The rotor 20 rotates about the center axis J. The rotor 20 includes a shaft 21, a rotor core 22, a plurality of (8 in the present embodiment) magnetic poles 28 arranged in the circumferential direction on the outer circumferential surface of the rotor core 22, and a holder 40. The rotor 20 may further include a cylindrical cover member surrounding the entire rotor from the outside in the radial direction.

The shaft 21 has a cylindrical shape extending in the axial direction around the central axis J. The shaft 21 is rotatably supported by a pair of bearings 15.

Fig. 2 is a perspective view of the rotor 20. Fig. 3 is a partial sectional view of the rotor 20.

As shown in fig. 2 and 3, rotor core 22 extends in the axial direction along central axis J. Rotor core 22 has a substantially polygonal shape as viewed in the axial direction.

Rotor core 22 is made of a ferromagnetic material. The rotor core 22 of the present embodiment is formed of a plurality of magnetic members stacked in the axial direction.

Rotor core 22 is provided with a central hole 22h and a plurality of holes 22d that penetrate in the axial direction. The central hole 22h is located at the center of the rotor core 22 as viewed in the axial direction. The plurality of hole portions 22d are arranged around the central hole 22 h. The shaft 21 is inserted into the central hole 22h and fixed. Hole 22d is provided to reduce the weight of rotor core 22 and to reduce the weight of rotor core 22.

As shown in fig. 3, a plurality of (8) planar portions 22s arranged in the circumferential direction and a plurality of (8) groove portions 22c located between the planar portions 22s are provided on the outer circumferential surface of the rotor core 22 facing the radially outer side. The flat surface portion 22s is a flat surface perpendicular to the radial direction. The planar portion 22s extends over the entire axial length of the rotor core 22. The magnetic pole 28 is disposed in the flat surface portion 22s. Groove 22c extends over the entire axial length of rotor core 22. The groove 22c opens radially outward. The groove portion 22c has a wedge shape in which the groove width decreases toward the radial outside.

The 8 magnetic poles 28 are provided on the outer periphery of the rotor 20. The 8 magnetic poles 28 are fixed to different planar portions 22s. The 8 magnetic poles 28 are arranged at equal intervals along the circumferential direction. The magnetic flux directions of the circumferentially adjacent magnetic poles 28 are mutually reversed in the radial direction. That is, the magnetic poles 28 arranged in the circumferential direction are arranged such that the magnetic poles with the N-pole facing radially outward and the magnetic poles with the S-pole facing radially outward are alternately arranged along the circumferential direction.

The magnetic pole 28 includes a magnet portion 23 and an outer core portion 24 disposed radially outward of the magnet portion 23. The magnet portion 23 is a permanent magnet. The outer core portion 24 is made of a ferromagnetic material. Outer core portion 24 is made of, for example, the same material as rotor core 22.

Magnet portion 23 is disposed on planar portion 22s of rotor core 22. The outer core portion 24 is disposed on the radially outer side surface of the magnet portion 23. That is, in the magnetic pole 28, the magnet portion 23 and the outer core portion 24 are arranged in this order from the planar portion 22s toward the radial outside. The magnet portion 23 is covered with the outer core portion 24, and the outer core portion 24 is exposed radially outward. The circumferential ends of the magnet portions 23 and the circumferential ends of the outer core portions 24 are arranged to overlap each other when viewed in the radial direction. That is, the magnetic pole 28 is an embedded Magnet type (IPM) magnetic pole.

The magnet portion 23 has a rectangular shape in which the length along the circumferential direction is larger than the length in the radial direction when viewed in the axial direction. The magnet portion 23 has a magnet inner surface 23a facing radially inward and a magnet outer surface 23b facing radially outward. The magnet inner surface 23a and the magnet outer surface 23b are flat surfaces extending in a direction perpendicular to the radial direction.

The outer core portion 24 is formed of a plurality of magnetic members stacked in the axial direction. The magnetic member is plate-shaped. The plate-like magnetic member is, for example, an electromagnetic steel plate. The outer core portion 24 has a quadrangular shape as viewed in the radial direction. The outer core portion 24 has a radially inward core inner surface 24a and a radially outward core outer surface 24b. The core inner side surface 24a is a plane extending in a direction perpendicular to the radial direction. On the other hand, the core outer surface 24b is a curved surface extending uniformly in the axial direction. The core outer surface 24b is formed in an arc shape protruding radially outward when viewed in the axial direction. Therefore, the radial thickness of the outer core portion 24 increases from both circumferential ends toward the center portion (inward in the circumferential direction).

The case where the core outer surface 24b of the present embodiment has an arc shape is described. However, the shape of the core outer surface 24b is not limited to the present embodiment, and may be other shapes. For example, the core outer surface 24b may be a plane extending in a direction perpendicular to the radial direction.

The flat surface portions 22s of the rotor core 22 and the magnet inner surfaces 23a of the magnet portions 23 are in contact with each other so as to face each other in the radial direction. Further, the magnet outer surface 23b of the magnet portion 23 and the core inner surface 24a of the outer core portion 24 are in radially opposed contact. In the present embodiment, the magnet outer surface 23b and the core inner surface 24a are bonded to each other. Therefore, an adhesive layer is interposed at least partially between the magnet outer surface 23b and the core inner surface 24 a.

As shown in fig. 2, the holder 40 is embedded and held in at least a part of the rotor core 22 and the magnetic poles 28. The holder 40 is made of a resin material. In the present embodiment, the holder 40 is molded by insert molding in which the rotor core 22 and a part of the magnetic pole 28 are embedded.

The holder 40 has a plurality of (8 in the present embodiment) columnar portions 48 and 2 cap portions 43 extending in the axial direction. The cover portions 43 are respectively located on the upper and lower sides of the plurality of columnar portions 48. The lid portion 43 has a flat plate shape perpendicular to the axial direction. Lid 43 is connected to 8 columnar portions 48. The cover portion 43 covers at least a part of the upper surface or the lower surface of the rotor core 22 and the plurality of magnetic poles 28. Therefore, the rotor core 22 and the magnetic poles 28 are sandwiched between the pair of lid portions 43 in the axial direction. Thereby, the holder 40 holds the rotor core 22 and the magnetic poles 28 from both axial sides. The holder 40 suppresses the magnetic poles 28 from being disengaged from the rotor core 22 in the axial direction.

The columnar portion 48 extends in a columnar shape extending in the axial direction with a uniform cross-sectional shape. The plurality of columnar portions 48 are arranged at equal intervals in the circumferential direction. The magnetic poles 28 are disposed between the circumferentially adjacent columnar portions 48.

As shown in fig. 3, the columnar portion 48 has an anchor portion 48c, a partition wall portion 48d, and a pair of retaining pieces 48b. That is, the holder 40 has the anchor portion 48c, the partition wall portion 48d, and the holding piece 48b.

The anchor portion 48c is molded by filling the groove portion 22c with a molten resin and solidifying the resin. Anchor portion 48c is disposed in wedge-shaped groove portion 22c provided on the outer surface of rotor core 22 in the radial direction. Further, the circumferential width of the anchor portion 48c increases toward the radially inner side. The columnar portion 48 suppresses the movement of the anchor portion 48c radially outward with respect to the rotor core 22. As a result, the plurality of magnetic poles 28 held by the columnar portion 48 are suppressed from moving radially outward.

The partition wall 48d is located radially outward of the anchor portion 48c, and is connected to the anchor portion 48 c. The partition wall portion 48d separates circumferentially adjacent magnetic poles 28 from each other. That is, the partition wall portion 48d is located between the magnetic poles 28 in the circumferential direction.

The pair of holding pieces 48b is connected to the partition wall portion 48 d. The pair of holding pieces 48b extend from the partition wall portion 48d to both circumferential sides. The retaining piece 48b has a plate shape extending along the circumferential direction. The outer peripheral surface of the retaining piece 48b is curved with a curvature centered on the central axis J. The holding piece 48b is disposed radially outward of the magnetic pole 28. The holding piece 48b covers a part of the outer peripheral surface of the magnetic pole 28. Thereby, the holding pieces 48b suppress the magnetic poles 28 from moving radially outward.

(method of manufacturing rotor)

Next, a method for manufacturing the rotor 20 of the present embodiment will be described.

Fig. 4 is a flowchart illustrating a method of manufacturing the rotor 20 according to the present embodiment.

The method of manufacturing the rotor 20 of the present embodiment mainly includes a magnetic pole manufacturing step S100, a rotor core molding step S200, and a magnetic pole fixing step S300.

The method of manufacturing the rotor 20 of the present embodiment uses the magnetic poles 28 manufactured in the magnetic pole manufacturing step S100 (i.e., the method of manufacturing the magnetic poles 28) described later and the rotor core 22 manufactured in the rotor core forming step S200. In the method of manufacturing the rotor 20, the rotor 20 is completed by fixing the magnetic poles 28 and the rotor core 22 in the magnetic pole fixing step S300.

(method of manufacturing magnetic pole)

The magnetic pole manufacturing step S100 includes a magnet forming step S110, an outer core forming step S120, an outer core fixing step S130, and an outer periphery machining step S140. That is, the method of manufacturing the magnetic pole 28 according to the present embodiment includes a magnet forming step S110, an outer core forming step S120, an outer core fixing step S130, and an outer periphery processing step S140.

(magnet Molding Process)

The magnet molding step S110 is a step of molding the magnet portion 23. The magnet portion 23 is molded by a conventionally known manufacturing method. In the magnet forming step S110, the magnet portion 23 is formed into a cube having a final shape. The magnet forming step S110 includes, for example, a sintering step, a polishing step for stabilizing the outer dimensions of the sintered magnet portion 23, and a magnetizing step for magnetizing the magnet portion 23.

(outer core Molding Process)

Fig. 6 is a flowchart of the outer core forming step S120 according to the present embodiment. The outer core forming step S120 is a step of forming the outer core portion 24. The outer core forming step S120 includes a laminating step S121 and a magnetic member fixing step S122.

The laminating step S121 is a step of laminating a plurality of magnetic members formed by rolling and press working in the thickness direction. The magnetic member fixing step S122 is a step of fixing the plurality of laminated magnetic members to each other. The magnetic member fixing step S122 is, for example, a pressure bonding step of plastically deforming the stacked plate-shaped magnetic members to fix them to each other. The magnetic member fixing step S122 may be a welding step of fixing the stacked plurality of magnetic members by welding, for example.

According to the outer core forming step S120 of the present embodiment, since a plurality of magnetic members are stacked, the outer core portion 24 can be stably manufactured. In the present embodiment, the rotor core 22 and the stator core 31 are formed of a plurality of magnetic members. Therefore, by adopting the outer core molding step S120 of the present embodiment, the outer core portion 24 can be manufactured using the same manufacturing apparatus as the manufacturing steps of the rotor core 22 and the stator core 31, and therefore, the outer core portion 24 can be manufactured at low cost.

In the outer core portion 24 of the present embodiment, a plurality of magnetic members are stacked in the axial direction. However, the outer core portion 24 may be formed of magnetic members stacked in the radial direction.

(modification of outer core Molding Process)

Fig. 7 is a flowchart of an outer core forming step S120A according to a modification. In the case of this modification, the outer core portions 24 are not formed by connecting a plurality of magnetic members, but are formed by a single member. The outer core forming step S120A of the present modification includes a drawing step S121A and a cutting step S122A.

The drawing step S121A is a step of drawing the magnetic member in the outer core forming step S120A. By going through the drawing step S121A, the magnetic member is processed into a columnar member extending in the drawing direction with a uniform cross section. The cutting step S122A is a step of cutting the magnetic member having passed through the drawing step S121A in the drawing direction. The magnetic member becomes the outer core portion 24 having a predetermined dimension in the axial direction by going through the cutting step S122A.

According to the outer core forming step S120A of the present modification, since the outer shape of the outer core portion 24 is formed by drawing, the loss of the magnetic material is small, and the outer core portion 24 can be manufactured at low cost in mass production. In addition, the outer shape of the outer core portion 24 can be molded with relatively high accuracy.

(outer iron core fixing step)

As shown in fig. 4, the outer core fixing step S130 is performed after the magnet forming step S110 and the outer core forming step S120. The outer core fixing step S130 is a step of fixing the outer core portion 24 to the magnet outer side surface 23b of the magnet portion 23. In the present embodiment, the outer core fixing step S130 is a step of bonding and fixing the magnet portion 23 and the outer core portion 24.

According to the present embodiment, by performing the bonding and fixing step as the outer core fixing step S130, the magnet portion 23 and the outer core portion 24 can be fixed to each other without using any other member, and the magnetic pole 28 can be manufactured at low cost. In the outer core fixing step S130 of the present embodiment, the magnetic poles 28 can be manufactured without affecting the characteristics of the magnet portion 23 and the outer core portion 24, as compared with other fixing means that perform pressure welding and heat treatment.

(outer periphery processing step)

The outer periphery processing step S140 is performed after the outer core fixing step S130. The outer periphery machining step S140 is a step of machining the core outer surface 24b of the outer core portion 24 to improve the dimensional accuracy of the core outer surface 24b.

Fig. 5 is a schematic view showing the outer periphery processing step S140. In the present embodiment, the outer peripheral machining step S140 is performed using the polishing apparatus 90. The polishing apparatus 90 includes a holding jig 91, a grinder portion 92, and a driving portion (not shown) for rotating the grinder portion 92.

The grindstone portion 92 has an annular shape centered on the rotation axis O. The grinder portion 92 is rotated about the rotation axis O by a drive portion not shown. The grinder portion 92 has a grinding surface 92a extending in the circumferential direction of the rotation axis O. The polishing surface 92a is a concave surface recessed inward in the radial direction of the rotation axis O. The grinding surface 92a is curved radially outward of the rotation axis O as going from the axial center of the rotation axis O to one side and the other side in the axial direction.

The holding jig 91 holds the magnetic pole 28. The holding jig 91 includes a pair of gripping portions 91b, a support surface 91a, and a pressing mechanism (not shown).

The support surface 91a is a flat surface along a plane perpendicular to the radial direction of the rotation axis O. The support surface 91a is in surface contact with the magnet inner surface 23a of the magnet portion 23 to support the magnetic pole 28. The magnetic pole 28 is positioned in the radial direction of the rotation axis O by bringing the magnet inner surface 23a into contact with the support surface 91 a.

The pair of gripping portions 91b grip the magnetic poles 28 from both sides in the circumferential direction. The magnetic pole 28 is positioned in the axial direction of the rotation axis O by being gripped by the gripping portion 91 b.

The holding jig 91 moves the grip portion 91b and the support surface 91a radially inward of the rotation axis O by the pressing mechanism. Thereby, the magnetic pole 28 is pressed against the grinding surface 92a of the rotating grindstone portion 92, and the core outer surface 24b of the outer core portion 24 is ground. Then, the rotational axis O of the grinder portion 92 is moved in the depth direction of the drawing sheet of fig. 5, and the entire core outer surface 24b is ground.

The outer periphery machining step S140 of the present embodiment is a step of polishing the core outer surface 24b of the outer core portion 24. As the outer peripheral machining step S140, by employing a grinding step, it is possible to form the core outer side surfaces 24b with high accuracy while removing burrs and the like of the magnetic members constituting the outer core portions 24. In addition, as the outer peripheral processing step S140, cutting using an end mill or the like may be employed.

According to the outer peripheral machining step S140 of the present embodiment, after the magnet portion 23 and the outer core portion 24 are fixed, the core outer surface 24b of the outer core portion 24 is machined. Therefore, the dimensional tolerance as the magnetic pole 28 can be reduced as compared with a case where the magnet portion 23 and the outer core portion 24 are separately machined and fixed. Further, compared to the case where the magnet portion 23 and the outer core portion 24 are separately machined, the number of times of machining in the manufacturing process can be reduced, and the manufacturing cost of the magnetic pole 28 can be reduced.

According to the outer peripheral machining step S140 of the present embodiment, the magnet portion 23 and the outer core portion 24 are radially superposed and fixed, and then the outer core portion 24 is machined. Therefore, it is easy to secure a region where the holding portion 91b of the polishing apparatus 90 holds the magnetic pole 28, and the processing of the core outer surface 24b is not easily restricted by the holding of the magnetic pole 28. As a result, the degree of freedom in designing the shape of the core outer surface 24b can be increased.

According to the outer peripheral machining step S140 of the present embodiment, the outer core portion 24 is fixed to the magnet portion 23 when the core outer surface 24b is machined. Therefore, even if the core outer surface 24b is formed to be thin in the radial direction, the outer core portion 24 is less likely to be damaged by being reinforced by the magnet portion 23. According to the present embodiment, the thickness of the outer core portion 24 can be determined without being affected by the risk of damage to the outer core portion 24 during machining of the core outer surface 24b, and the degree of freedom in designing the magnetic pole 28 for obtaining desired magnetic characteristics can be improved.

The outer core portion 24 of the present embodiment is thinnest at both circumferential end portions. Therefore, the outer peripheral machining step S140 of the present embodiment is a step of performing machining such that the thickness dimension in the radial direction of the outer core portion 24 becomes smaller from the center in the circumferential direction toward both sides in the circumferential direction. As described above, since the outer core portions 24 are reinforced by the magnet portions 23, the end portions on both sides in the circumferential direction of the outer core portions 24 can be formed into a sharp shape. As a result, the magnetic properties at both circumferential ends of the magnetic pole 28 can be continuously changed.

In addition, in the case of adopting a manufacturing method in which the outer core portion 24 is fixed to the magnet portion 23 after machining and then the core outer side surface 24b is not machined, the angle R or the straight portion is generally required to be provided at both ends in the circumferential direction of the outer core portion 24, and the outer core portion cannot be formed into a sharp shape. Fig. 12 shows an example of the outer shape of the outer core portion 24 of the present embodiment, which cannot be manufactured by the conventional manufacturing method but can be manufactured only by the manufacturing method of the present embodiment. Fig. 13 and 14 show the outer shapes of the outer core portions 1024 and 2024 manufactured by a conventional manufacturing method as a comparative example.

In the present embodiment, the case where only the core outer surface 24b of the outer core portion 24 is processed in the outer peripheral processing step S140 is described. However, when the thickness of the outer core portion 24 in the radial direction is reduced, a part of the magnet portion 23 may be exposed in the radial direction and polished together with the outer core portion 24. That is, in the outer peripheral machining step S140, the magnet portion 23 may be machined together with the outer core portion 24.

According to the outer peripheral processing step S140 of the present embodiment, the polishing apparatus 90 performs polishing processing on the core outer surface 24b while supporting the magnet inner surface 23a by the supporting surface 91 a. That is, in the outer peripheral machining step S140 of the present embodiment, the core outer side surface (surface facing radially outward) 24b of the outer core portion 24 is machined with reference to the magnet inner side surface (surface facing radially inward) 23 a. Therefore, the dimensional accuracy between the magnet inner surface 23a and the core outer surface 24b (i.e., the dimensional accuracy in the radial direction of the magnetic pole 28) can be determined by the machining accuracy in the outer periphery machining step S140. Further, by forming the rotor 20 using the magnetic poles 28 with improved dimensional accuracy in the radial direction, the rotor 20 with high dimensional accuracy in the outer diameter can be configured. As a result, the air gap between the rotor 20 and the stator 30 can be reduced, and the driving efficiency of the motor 1 can be improved.

The polishing apparatus 90 that performs the outer peripheral processing step S140 according to the present embodiment can be used by, for example, partially modifying a polishing apparatus for polishing a magnetic pole portion used for a magnetic pole of a Surface Magnet type (SPM). Therefore, when the outer peripheral machining step S140 of the present embodiment is employed, introduction of a new polishing apparatus 90 may not be necessary, and the cost for equipment investment may be reduced.

(rotor core Molding Process)

Rotor core molding step S200 is a step of molding rotor core 22. The rotor core forming step S200 may have the same structure as the outer core forming step S120. That is, the rotor core forming step S200 includes a lamination step of laminating magnetic members and a magnetic member fixing step of fixing the magnetic members to each other. As a modification of the rotor core forming step S200, the drawing step and the cutting step may be provided in the same manner as the outer core forming step S120A (see fig. 7) of the above-described modification.

(magnetic pole fixing step)

The magnetic pole fixing step S300 is a step of fixing the magnet inner side surface 23a of the magnet portion 23 to the outer peripheral surface (i.e., the flat surface portion 22S) of the rotor core 22 facing the radially outer side. As shown in fig. 2 and 3, in the rotor 20 of the present embodiment, the rotor core 22 and the magnetic poles 28 are fixed to each other by the holder 40. Therefore, the magnetic pole fixing step S300 of the present embodiment is a step of integrally molding the rotor core 22 and the magnetic poles 28 with resin.

Fig. 8 is a flowchart of the magnetic pole fixing step S300 according to the present embodiment. Fig. 9 is a partial sectional view of the mold 3 in which the retainer 40 is molded.

As shown in fig. 8, the magnetic pole fixing step S300 of the present embodiment includes the steps of: a placement step S310 of housing the rotor core 22 and the plurality of magnetic poles 28 in the mold 3; and a molding step S320 of injecting a molten resin into the mold 3.

As shown in fig. 9, the mold 3 is provided with a cavity C that houses the rotor core 22 and the plurality of magnetic poles 28. The hollow C is substantially circular when viewed in the axial direction. In the disposing step S310 of the magnetic pole fixing step S300, the rotor core 22 and the plurality of magnetic poles 28 are disposed in the cavity C.

In the molding step S320 of the magnetic pole fixing step S300, a molten resin is injected into the cavity C of the mold 3. The molten resin is solidified in the cavity C. Thereby, the holder 40 holding the rotor core 22 and the magnetic poles 28 is molded. The rotor 20 is released from the mold 3 after being cooled. Thereby, the rotor 20 is manufactured.

According to the present embodiment, the holder 40 is molded by insert molding in which the magnetic poles 28 and the rotor core 22 are embedded. Therefore, as shown in fig. 2, the holder 40 can hold the magnetic poles 28 and the holder 40 by sandwiching the magnetic poles 28 and the rotor core 22 from the top and bottom direction by the lid portion 43.

In a conventional manufacturing method, for example, the rotor core, the magnet portion, and the outer core portion are individually disposed in a mold and integrally molded with resin. In the case of adopting such a manufacturing method, the rotor core, the magnet portion, and the outer core portion need to be positioned in the mold, respectively, and thus there is a problem that the structure of the mold becomes complicated.

In contrast, according to the manufacturing method of the present embodiment, the magnet portion 23 and the outer core portion 24 are fixed in advance to constitute 1 member, i.e., the magnetic pole 28, in the magnetic pole fixing step S300. Therefore, when the magnet portion 23 and the outer core portion 24 are disposed in the mold 3, it is not necessary to position them with each other, and the structure of the mold 3 can be simplified.

Further, according to the manufacturing method of the present embodiment, since the dimensional accuracy of the magnetic pole 28 in the radial direction is high, the dimensional tolerance of the magnetic pole 28 in consideration of the design of the mold 3 can be reduced as compared with the conventional mold. As a result, the dimensional accuracy of the rotor 20 molded by the mold 3 can be improved.

The mold 3 used in the magnetic pole fixing step S300 of the present embodiment can be used by partially modifying a mold used for molding a Surface Magnet type (SPM) holder, for example. Therefore, in the case of adopting the magnetic pole fixing step S300 of the present embodiment, there is a case where it is not necessary to introduce a new mold 3, and the cost for equipment investment can be reduced.

(modification of magnetic pole fixing step)

Fig. 10 is a flowchart of a magnetic pole fixing step S300A according to a modification. Fig. 11 is a schematic diagram illustrating a magnetic pole fixing step S300A of a modification.

As shown in fig. 11, in the present modification, the rotor 120 includes a rotor core 22, a plurality of magnetic poles 28, a holder 140, and a cylindrical cover member 129.

The cage 140 of the present modification includes a base portion 143 disposed on the lower side of the rotor core 22 and a plurality of columnar portions 148 extending upward from the base portion 143. The columnar portion 148 has: an anchor portion 148c inserted into the groove portion 22c of the rotor core 22; a partition wall portion 148d located radially outward of the anchor portion 148 c; and holding pieces 148b extending from the partition wall portion 148d to both circumferential sides. A magnetic pole housing portion 149 that opens in the axial direction (upper side in the present embodiment) is provided between the partition wall portions 148d of the plurality of columnar portions 148 arranged in the circumferential direction.

The cover member 129 of the present modification is cylindrical with the center axis J as the center. The cover member 129 surrounds the holder 140 and the plurality of magnetic poles 28 from the radially outer side, and suppresses the magnetic poles 28 from moving radially outward. The cover member 129 is made of a nonmagnetic substance such as an aluminum alloy or a resin material.

As shown in fig. 10, the magnetic pole fixing step S300A of the present modification includes a holder molding step S310A, a magnetic pole housing step S320A, and a cover attaching step S330A. The holder forming step S310A is a step of molding the rotor core 22 with resin to form the holder 140. The magnetic pole housing step S320A is a step of inserting the magnetic pole 28 into the magnetic pole housing portion 149 of the holder 140. The cover mounting step S330A is a step of covering the holder 140 into which the magnetic poles 28 are inserted with a cover.

In the magnetic pole housing step S320A, the magnetic pole 28 is press-fitted into the magnetic pole housing portion 149 of the holder 140. The magnetic pole 28 manufactured by the magnetic pole manufacturing method described above has higher outer diameter dimensional accuracy than a conventional magnetic pole. That is, since the press-fitting dimension of the magnetic pole 28 into the magnetic pole housing 149 can be stably controlled, the press-fitting can be realized.

While the embodiment of the present invention and the modification thereof have been described above, the configurations of the embodiment and the modification, and the combination thereof, are examples, and addition, omission, replacement, and other modifications of the configurations may be made within the scope not departing from the gist of the present invention. The present invention is not limited to the embodiments and the modifications thereof.

For example, the shape of the magnet and the shapes of the outer cores are not limited to the examples described in the above embodiment and modification. The number of poles of the rotor and the number of slots of the stator are not limited to the above-described embodiments.

The method of joining the reinforcing portion to the retainer in the above-described embodiment and modification is an example, and other fixing methods may be employed. For example, the reinforcement portion may also be mechanically engaged with the cage by snap-fitting or the like.

Claims (9)

1. A method for manufacturing a magnetic pole provided on the outer periphery of a rotor rotating around a central axis and having a magnet portion and an outer core portion disposed radially outside the magnet portion,

the method for manufacturing the magnetic pole comprises the following steps:

an outer iron core molding step of molding the outer iron core portion;

an outer core fixing step of fixing the outer core portion to a radially outward surface of the magnet portion; and

and an outer periphery machining step of machining a surface of the outer core portion facing radially outward with reference to a surface of the magnet portion facing radially inward.

2. The method of manufacturing a magnetic pole according to claim 1,

the outer peripheral machining step is a step of polishing a surface of the outer core portion facing radially outward.

3. The method of manufacturing a magnetic pole according to claim 1 or 2,

the outer periphery machining step is a step of performing machining such that the thickness dimension in the radial direction of the outer core portion becomes smaller from the center in the circumferential direction toward both sides in the circumferential direction.

4. The manufacturing method of a magnetic pole according to any one of claims 1 to 3,

the outer iron core forming process comprises the following steps:

a laminating step of laminating a plurality of magnetic members; and

and a magnetic member fixing step of fixing the plurality of laminated magnetic members to each other.

5. The method of manufacturing a magnetic pole according to any one of claims 1 to 3,

the outer iron core forming process comprises the following steps:

a drawing step of drawing the magnetic member; and

and a cutting step of cutting the magnetic member subjected to the drawing step in a drawing direction.

6. The method of manufacturing a magnetic pole according to any one of claims 1 to 5,

the outer core fixing step is a step of bonding and fixing the magnet portion and the outer core portion.

7. A method of manufacturing a rotor, wherein,

the method for manufacturing the rotor comprises the following magnetic pole fixing steps: a surface of the magnet portion facing radially inward is fixed to an outer peripheral surface of the rotor core facing radially outward using the magnetic pole manufactured by the method for manufacturing a magnetic pole according to any one of claims 1 to 6 and the rotor core extending in an axial direction around the central axis.

8. The method of manufacturing a rotor according to claim 7,

the magnetic pole fixing step is a step of integrally molding the rotor core and the magnetic poles with a resin.

9. The method of manufacturing a rotor according to claim 7,

the magnetic pole fixing process comprises the following steps:

a holder molding step of molding the rotor core with resin to mold a holder provided with a magnetic pole housing section that is open in an axial direction;

a magnetic pole housing step of inserting the magnetic pole into the magnetic pole housing section; and

and a cover mounting step of covering the holder into which the magnetic pole is inserted with a cover.

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