Rotor, motor and manufacturing method of rotor

Abstract

To provide a rotor which can position a magnet with a simple structure.SOLUTION: A rotor 1 which can rotate around a central axis extending in an axial direction includes a yoke 13 being a cylindrical magnetic body extending in the axial direction. A plurality of protruding parts 132 of the yoke are connected to one end parts in the axial direction of a cylindrical yoke cylinder part 131 extending in the axial direction and are arranged in a circumferential direction with intervals. In each protruding part, a protrusion 1321 protrudes radially inward from one end part in the axial direction of the yoke cylinder part. An extension 1322 extends in the other axial direction along an inner face in a radial direction of the yoke cylinder part from an inner end part in the radial direction of the protrusion. A magnet 14 is arranged between the adjacent extensions in the circumferential direction. The protruding parts are integrally constituted as a single member with the yoke cylinder part.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a rotor, a motor, and a method for manufacturing a rotor. [Background technology]

[0002] Conventionally, motors equipped with a rotor with multiple magnets arranged in the circumferential direction are known. For example, the rotor has a magnet holder in which two annular parts spaced apart in the axial direction are connected by multiple supports. Each of the multiple magnets is held in a space formed by the two annular parts and two supports adjacent to each other in the circumferential direction (see JP 2014-217161 A). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-217161 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, if a holder dedicated to positioning the magnet is provided on the rotor, the rotor structure becomes complicated and the number of parts increases, which may reduce the efficiency of assembly.

[0005] An object of the present invention is to provide a rotor that allows magnet positioning with a simple configuration. [Means for solving the problem]

[0006] An exemplary rotor of the present invention is rotatable around a central axis extending in the axial direction. The rotor includes a yoke. The yoke is a cylindrical magnetic body extending in the axial direction. A plurality of magnets arranged in a circumferential direction are arranged on a radially inner surface of the yoke. The yoke has a cylindrical yoke tube portion and a protruding portion. The yoke tube portion extends in the axial direction. The protruding portions are arranged at one axial end of the yoke tube portion, and are arranged in a plurality of circumferential directions at intervals. Each of the protruding portions has a protrusion and an extension portion. The protrusion protrudes radially inward from one axial end of the yoke tube portion. The extension portion extends from a radially inner end of the protrusion to the other axial direction along the radially inner surface of the yoke tube portion. The magnets are arranged between the extension portions adjacent to each other in the circumferential direction. The protruding portions are integrally formed with the yoke tube portion as a single member.

[0007] An exemplary motor of the present invention includes the rotor described above.

[0008] In an exemplary rotor manufacturing method of the present invention, a rotor that can rotate around a central axis extending in the axial direction is manufactured. In the rotor, a plurality of extensions are arranged side by side at intervals in the circumferential direction. The extensions extend in the axial direction with respect to a radially inner surface of the axially extending yoke cylindrical portion. In addition, magnets are arranged between the extensions that are adjacent in the circumferential direction. The rotor manufacturing method includes a step of forming the extensions by bending, using the bases of the pillars as a fulcrum, a plurality of pillars that protrude from one axial end of the yoke cylindrical portion and are arranged side by side in the circumferential direction at intervals. Effect of the Invention

[0009] According to the exemplary rotor, motor, and rotor manufacturing method of the present invention, it is possible to provide a rotor that allows magnet positioning with a simple configuration. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration example of a motor. [Diagram 2]FIG. 2 is a perspective view of the rotor. [Diagram 3] FIG. 3 is an exploded perspective view of the rotor. [Figure 4] FIG. 4 is a flowchart illustrating an example of a method for manufacturing a rotor. [Figure 5A] FIG. 5A is a schematic diagram showing an example of a process for forming a plate-shaped member from a plate-shaped magnetic body. [Figure 5B] FIG. 5B is a schematic diagram showing an example of a process for forming a yoke cylindrical portion by drawing a plate-shaped member. [Figure 5C] FIG. 5C is a schematic diagram showing an example of a process for arranging an extension portion on the radially inner surface of the yoke cylindrical portion by folding and overlapping the pillar portion. [Figure 6] FIG. 6 is a flowchart illustrating another example of a method for manufacturing a rotor. [Figure 7A] FIG. 7A is a schematic diagram showing an example of a process for forming another plate-shaped member from a plate-shaped magnetic body. [Figure 7B] FIG. 7B is a schematic diagram showing an example of a process for forming a cylindrical yoke portion by bending a plate-shaped member. [Figure 7C] FIG. 7C is a schematic diagram showing an example of a process for arranging an extension portion on the radially inner surface of the yoke cylindrical portion by folding and overlapping the pillar portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Exemplary embodiments are described below with reference to the drawings.

[0012] In this specification, in the motor 100, the direction parallel to the central axis CA is referred to as the "axial direction." Within the axial direction, the direction from the rotor 1 to the base portion 31, which will be described later, is referred to as the "one axial direction Da," and the direction from the base portion 31 to the rotor 1 is referred to as the "other axial direction Db." Additionally, the direction perpendicular to the central axis CA is referred to as the "radial direction," and the direction of rotation about the central axis CA is referred to as the "circumferential direction." Within the radial direction, the direction approaching the central axis CA is referred to as the "radial inward," and the direction away from the central axis CA is referred to as the "radial outward."

[0013] In this specification, "annular" refers not only to a shape that is continuous and uninterrupted throughout the entire circumferential area centered on the central axis CA, but also to a shape that has one or more interruptions in a portion of the entire area centered on the central axis CA. It also refers to a shape that describes a closed curve on a curved surface that intersects with the central axis CA.

[0014] In addition, in the positional relationship between any one of a direction, a line, and a plane and any other, "parallel" includes not only a state in which the two do not intersect at all no matter how far they are extended, but also a state in which they are substantially parallel. Furthermore, "perpendicular" and "orthogonal" each include not only a state in which the two intersect at 90 degrees, but also a state in which they are substantially perpendicular and a state in which they are substantially orthogonal, respectively. In other words, "parallel," "perpendicular," and "orthogonal" each include a state in which there is an angle deviation in the positional relationship between the two to an extent that does not deviate from the gist of the present invention.

[0015] Note that these are names used merely for the purpose of explanation, and are not intended to limit the actual positional relationships, directions, names, and the like.

[0016] <1. Embodiment> Fig. 1 is a cross-sectional view showing a schematic configuration example of a motor 100. Fig. 1 shows the cross-sectional structure when the motor 100 is virtually cut along a plane that is parallel to the axial direction and includes a central axis CA.

[0017] <1-1.Motor 100> 1, the motor 100 includes a shaft 101, a rotor 1, a stator 2, a housing 3, and a circuit board 4. As described below, the motor 100 can provide a rotor 1 that allows the magnets 14 to be positioned with a simple and inexpensive configuration, thereby improving the productivity of the rotor 1. In addition, it can suppress or prevent the magnets 14 from being arranged at an angle when viewed from the radial direction, or from contacting each other between adjacent magnets 14 in the circumferential direction.

[0018] The shaft 101 extends in the axial direction along the central axis CA and is rotatable around the central axis CA. That is, in this embodiment, the shaft 101 is a rotating shaft. However, without being limited to this example, the shaft 101 may be a fixed shaft fixed together with the stator 2, or may be unable to rotate around the central axis CA. If the shaft 101 is a fixed shaft, a bearing is disposed between the shaft 101 and the rotor 1 to rotatably support the rotor 1 relative to the shaft 101.

[0019] The rotor 1 is rotatable about a central axis CA extending in the axial direction. The rotor 1 has a rotor lid portion 11, a rotor cylinder portion 12, a yoke 13, and a plurality of magnets .

[0020] The rotor lid portion 11 is fixed to one axial end of the shaft 101. As described above, the rotor 1 includes the rotor lid portion 11. The rotor lid portion 11 is disposed on the other axial side Db of the stator 2 and the yoke 13 (particularly the protrusion portion 132 described later), and extends in the radial direction.

[0021] In this embodiment, the rotor lid 11 has a hole 111 and an opening 112. The hole 111 is disposed on one axial end face of the rotor lid 11 in the radial center of the rotor lid 11. In this embodiment, the hole 111 is a recess recessed toward the other axial direction Db, but is not limited to this example and may be a through hole extending in the axial direction. One axial end of the shaft 101 is inserted and fixed into the hole 111. The openings 112 open toward the one axial direction Da and the other axial direction Db of the rotor lid 11, are disposed radially outward from the hole 111, and are arranged in a plurality in the circumferential direction.

[0022] The rotor cylindrical portion 12 has a cylindrical shape extending in one axial direction Da from the radial outer end portion of the rotor lid portion 11. As described above, the rotor 1 includes the rotor cylindrical portion 12. The rotor cylindrical portion 12 surrounds the stator 2, the yoke 13, and the like.

[0023] The yoke 13 is disposed on the radially inner surface of the rotor cylindrical portion 12 and surrounds the stator 2. As described above, the rotor 1 has the yoke 13. The yoke 13 is a cylindrical magnetic body extending in the axial direction. A plurality of magnets 14 are disposed on the radially inner surface of the yoke 13 and aligned in the circumferential direction.

[0024] The magnets 14 face each other in the radial direction, surrounding the stator 2 (particularly the stator core 21 described later). The magnets 14 are arranged at intervals in the circumferential direction. The magnetic poles (S poles, N poles) on the radially inner side of the magnets 14 adjacent to each other in the circumferential direction are alternately different.

[0025] Next, the stator 2 rotates the rotor 1 by magnetic flux generated by energization. As shown in FIG.

[0026] A plurality of coil portions 23 are arranged in the circumferential direction in the stator core 21. The stator core 21 is an annular magnetic body surrounding the shaft 101, and in this embodiment is a laminated body in which plate-shaped electromagnetic steel sheets extending in the radial direction are stacked in the axial direction. The stator core 21 is fixed to the radial outer surface of a holder tube portion 32, which will be described later. The stator core 21 also has slots (not shown). A plurality of the slots are arranged in the circumferential direction, penetrating the stator core 21 in the axial direction.

[0027] The insulators 22 have electrical insulation properties and are arranged on the surfaces of the stator core 21 (particularly, both axial end faces and inner surfaces of the slots, etc.).

[0028] The coil portion 23 is a member in which a conductor wire (reference number omitted) is arranged in a coil shape on the stator core 21 via the insulator 22. The conductor wire is, for example, an enamel-coated copper wire, a metal wire coated with an electrical insulating material, or the like, and the coil portion 23 is formed by being wound around teeth (not shown) between circumferentially adjacent slots of the stator core 21. When a driving current is supplied to each coil portion 23, the stator 2 is excited to drive the rotor 1.

[0029] Next, the housing 3 has a base portion 31 and a holder tubular portion 32. The base portion 31 is disposed on one axial direction Da from the stator 2 and expands in the radial direction. The holder tubular portion 32 is tubular and extends from the other axial direction end face of the base portion 31 to the other axial direction Db. The holder tubular portion 32 surrounds the shaft 101 and supports the stator core 21.

[0030] A bearing 321 is disposed on the inner circumferential surface (i.e., the radially inner surface) of the holder tubular portion 32, and the shaft 101 is inserted through the bearing 321. The holder tubular portion 32 rotatably supports the shaft 101 via the bearing 321. Note that the bearing 321 may be a rolling bearing such as a ball bearing, a sliding bearing, a fluid dynamic bearing, or the like.

[0031] Next, the circuit board 4 is disposed on one axial side Da of the stator 2, and is supported by the holder tube portion 32. In FIG. 1, the circuit board 4 extends radially outward from the radially outer surface of the holder tube portion 32. The circuit board 4 is electrically connected to a lead wire (not shown) drawn from the coil portion 23. A drive circuit for the stator 2 and the like are mounted on the circuit board 4. In addition, external wiring (not shown) is electrically connected to the circuit board 4. The external wiring is drawn to the outside of the motor 100, and electrically connects the circuit board 4 to an external device, power source, and the like.

[0032] <1-2. York 13> Next, a configuration example of the yoke 13 will be described with reference to Fig. 1 to Fig. 3. Fig. 2 is a perspective view of the rotor 1. Fig. 3 is an exploded perspective view of the rotor 1. Note that in Fig. 2 and Fig. 3, the orientations of one axial direction Da and the other axial direction Db on the paper surface are reversed from those in Fig. 1.

[0033] 1 to 3, the yoke 13 has a yoke cylindrical portion 131 and protrusions 132. The yoke cylindrical portion 131 is cylindrical and extends in the axial direction. The protrusions 132 are connected to one axial end of the yoke cylindrical portion 131 and are arranged at intervals in the circumferential direction.

[0034] Each of the protrusions 132 has a protrusion 1321 and an extension 1322. The protrusion 1321 protrudes radially inward from one axial end of the yoke tubular portion 131. The extension 1322 extends from the radially inner end of the protrusion 1321 in the other axial direction Db along the radially inner side surface of the yoke tubular portion 131. Preferably, the extension 1322 is disposed on the radially inner side surface of the yoke tubular portion 131 in contact with the yoke tubular portion 131. However, this example does not exclude a configuration in which the extension 1322 of at least one protrusion 132 does not contact the radially inner side surface of the yoke tubular portion 131. For example, the extension 1322 may face the radial direction with a gap between it and the radially inner side surface of the yoke tubular portion 131.

[0035] On the radial inner surface of the yoke cylindrical portion 131, a plurality of extensions 1322 are arranged with gaps in the circumferential direction. In this embodiment, the plurality of extensions 1322 are arranged at equal intervals in the circumferential direction. The magnets 14 are inserted into the gaps and fixed. That is, the magnets 14 are arranged between the extensions 1322 adjacent in the circumferential direction. The intervals We between the extensions 1322 adjacent in the circumferential direction are the same as the width Wm (e.g., circumferential width) of the magnets 14 in the axial direction and the direction perpendicular to the radial direction, as long as the magnets 14 can be arranged between the extensions 1322 adjacent in the circumferential direction. However, the above examples do not exclude a configuration in which the intervals We between the extensions 1322 adjacent in the circumferential direction are larger than the width Wm of the magnets 14 described above, and a configuration in which at least a plurality of extensions 1322 are arranged at different intervals in the circumferential direction.

[0036] The protrusions 132 are integrally formed with the yoke cylindrical portion 131 as a single member. In this way, the yoke cylindrical portion 131 and the multiple protrusions 132 protruding from one axial end of the yoke cylindrical portion 131 can be integrally formed as a single plate-like member 13a (see Figs. 5A and 7A described later) by, for example, pressing a plate-like magnetic material. The yoke cylindrical portion 131 is then formed into a cylindrical shape, and the multiple protrusions 132 are arranged in the circumferential direction. After that, each of the protrusions 132 is bent from its base and overlapped on the radially inner surface of the yoke cylindrical portion 131. This allows the multiple extensions 1322 extending in the axial direction to be easily arranged in the circumferential direction on the radially inner surface of the yoke cylindrical portion 131, and the magnet 14 can be arranged between the extensions 1322 adjacent to each other in the circumferential direction. That is, compared to a configuration in which the extensions 1322 are formed on the radially inner surface of the yoke cylindrical portion 131 by cutting or the like, the multiple extensions 1322 can be arranged on the radially inner surface of the yoke cylindrical portion 131 easily and inexpensively. Therefore, it is possible to provide a rotor 1 that allows the magnets 14 to be positioned with a simple and inexpensive configuration, thereby improving the productivity of the rotor 1. It is also possible to suppress or prevent the magnets 14 from being arranged at an angle when viewed from the radial direction, or the magnets 14 adjacent to each other in the circumferential direction from contacting each other.

[0037] Moreover, the rotor cylinder portion 12 surrounds the yoke cylinder portion 131 and contacts the radially outer side surface of the yoke cylinder portion 131. Moreover, the other axial end portion of the yoke cylinder portion 131 contacts the rotor cover portion 11. Since the protrusion portion 312 is folded from one axial end portion of the yoke cylinder portion 131 onto the radially inner side surface, the yoke 13 can be easily attached to the rotor cover portion 11 and the rotor cylinder portion 12 by inserting the other axial end portion of the yoke cylinder portion 131 toward the rotor cylinder portion 12 and abutting it against the rotor cover portion 11. Moreover, by inserting the magnet 14 between the extension portions 1322 adjacent in the circumferential direction from one axial direction Da side, the magnet 14 can be easily arranged on the radially inner side of the rotor cylinder portion 12 and the yoke 13.

[0038] Preferably, the other axial end of the extension 1322 is disposed on the other axial direction Db of the one axial end of the yoke cylindrical portion 131 and on the one axial direction Da of the other axial end of the yoke cylindrical portion 131. That is, the other axial end of the extension 1322 does not reach the one axial end of the yoke cylindrical portion 131. That is, the axial length L1 of the extension 1322 is equal to or less than the axial width W1 of the yoke cylindrical portion 131 (see FIG. 3). In this way, the axial length of the protrusion 132 before forming the protrusion 1321 by bending (that is, the axial length L2 of the column portions 132a and 132b in FIG. 5A and FIG. 7A described later) can be shortened. Therefore, the number of yokes 13 that can be formed from one magnetic body (see FIG. 5A to FIG. 5C and FIG. 7A to FIG. 7C described later) can be increased. Therefore, the production efficiency of the yoke 13 can be improved.

[0039] More preferably, the axial length L1 of the extension portion 1322 is equal to or greater than one-third (W1 / 3) of the axial width of the yoke cylindrical portion 131 and equal to or less than the axial width W1 of the yoke cylindrical portion 131. Even more preferably, the axial length L1 of the extension portion 1322 is equal to or greater than half (W1 / 2) of the axial width of the yoke cylindrical portion 131 and equal to or less than the axial width W1 of the yoke cylindrical portion 131. This makes it possible to prevent the magnets 14 arranged between circumferentially adjacent extension portions 1322 from being arranged at an angle when viewed from the radial direction. Therefore, the magnets 14 can be arranged with high precision.

[0040] If L1<(W1 / 2), there is a risk that the magnet 14 will be disposed at an angle when viewed from the radial direction. If L1<(W1 / 3), this risk increases even more.

[0041] Furthermore, when L1>W1, the other axial end of the extension 1322 protrudes in the other axial direction Db further than the other axial end of the yoke cylindrical portion 131. Therefore, the other axial end of the extension 1322 may come into contact with another member (for example, the rotor lid 11) or the like, which may hinder assembly of the rotor 1.

[0042] However, the above examples do not exclude configurations where L1<(W1 / 2) (and where L1<(W1 / 3)) and where L1>W1.

[0043] Also, preferably, the radial thickness t1 of the extension 1322 is the same as the radial thickness t2 of the yoke cylindrical portion 131. In this way, the yoke 13 with the extension 1322 disposed on the radially inner side can be formed from a single plate-shaped magnetic body without requiring a process for changing the thickness of the extension 1322. However, this example does not exclude a configuration where t1 is not approximately equal to t2. For example, t1 may be greater than t2, or t1 may be greater than t2. <t2であってもよい。

[0044] In the present embodiment, the circumferential width W2 of the protrusion 1321 of each protrusion 132 is the same as the circumferential width W3 of the extension 1322. However, this is not limited to the example, and the circumferential width W2 of the protrusion 1321 of at least one of the protrusions 132 may be smaller than the circumferential width W3 of the extension 1322. In this way, the base of the protrusion 132 protruding from the yoke tube portion 131 becomes easier to bend. Alternatively, the circumferential width W2 of the protrusion 1321 of at least one of the protrusions 132 may be larger than the circumferential width W3 of the extension 1322. In this way, when the protrusion 132 is bent, breakage from the base of the protrusion 132 can be prevented. When W2>W3, the magnet 14 can be inserted and fixed between the extensions 1322 adjacent to each other in the circumferential direction from the radially inner side toward the radially outer side.

[0045] <1-4. Manufacturing method of rotor 1> Next, an example of a manufacturing method of the rotor 1 will be described with reference to Fig. 3 to Fig. 5C. Fig. 4 is a flow chart for explaining an example of a manufacturing method of the rotor 1. Figs. 5A to 5C are schematic diagrams showing an example of a manufacturing process of the yoke 13. Fig. 5A is a schematic diagram showing an example of a process for forming the plate-shaped member 13a from a plate-shaped magnetic body. Fig. 5B is a schematic diagram showing an example of a process for forming the yoke cylindrical portion 131 by drawing the plate-shaped member 13a. Fig. 5C is a schematic diagram showing an example of a process for arranging the extension portion 1322 on the radially inner surface of the yoke cylindrical portion 131 by folding and overlapping the column portion 132a.

[0046] In the manufacturing method of the rotor 1 shown in Fig. 4, a plurality of axially extending extensions 1322 are arranged side by side at intervals in the circumferential direction on the radially inner surface of the yoke cylindrical portion 131. The yoke cylindrical portion 131 extends in the axial direction and is rotatable about a central axis CA extending in the axial direction. Furthermore, magnets 14 are arranged between the extensions 1322 adjacent to each other in the circumferential direction.

[0047] First, the yoke 13 shown in FIG. 3 is formed (step S1a).

[0048] In detail, as shown in FIG. 5A, a single plate-shaped member 13a is formed from a plate-shaped magnetic material by punching by press working or the like (step S11a). The plate-shaped member 13a includes a disk portion 131a and a plurality of pillar portions 132a in one body. The disk portion 131a is disk-shaped with an opening at the center. The plurality of pillar portions 132a protrude radially inward from the inner edge portion of the disk portion 131a. Step S1a includes step S11a. The "radial inward direction" in which the pillar portions 132a protrude is a direction approaching an axis corresponding to the central axis CA as a reference. The axis passes through the center of the opening of the disk portion 131a and extends parallel to the normal direction of the plate-shaped member 13a. The plurality of pillar portions 132a are arranged at equal intervals along the inner edge portion of the disk portion 131a.

[0049] Then, as shown in Fig. 5B, the disk portion 131a is drawn into a cylindrical shape extending in the normal direction of the plate-like member 13a by pressing (step S12a). This forms the yoke cylindrical portion 131 surrounding the central axis CA. Note that step S1a includes step S12a. Also, in Fig. 5B, the pillar portion 132a protrudes radially inward from one axial end of the yoke cylindrical portion 131.

[0050] According to steps S11a and S12a, the disk portion 131a of the single plate-shaped member 13a formed from a plate-shaped magnetic material can be made into a cylindrical shape by simple and inexpensive processes such as pressing and drawing. In addition, the seamless yoke cylindrical portion 131 can be formed with high precision. Therefore, the cylindrical yoke 13 in which the yoke cylindrical portion 131 and the protrusion portions 132 (pillar portions 132a in FIG. 5B) are integrally formed as a single member can be efficiently formed.

[0051] Thereafter, as shown in Fig. 5C, each of the pillar portions 132a is folded toward the other axial direction Db (step S13a). In detail, the pillar portions 132a are bent using the bases of the pillar portions 132a (the radially outer ends of the pillar portions 132a in Fig. 5C) as fulcrums to form the protrusions 132. The pillar portions 132a protrude from one axial end of the yoke cylindrical portion 131 and are arranged at intervals in the circumferential direction. Step S1a also includes step S13a.

[0052] According to step S13a, compared to a configuration in which the extension portion 1322 is formed on the radially inner surface of the yoke cylindrical portion 131 by cutting or the like, it is possible to provide a rotor 1 that can position the magnets 14 with a simpler and less expensive configuration, thereby improving the productivity of the rotor 1. In addition, it is possible to suppress or prevent the magnets 14 from being arranged at an angle when viewed from the radial direction, or the magnets 14 adjacent to each other in the circumferential direction from contacting each other.

[0053] Next, the yoke 13 shown in Fig. 3 is attached to the inside of the covered cylindrical member composed of the rotor lid 11 and the rotor cylinder 12 (step S2). In this embodiment, the yoke 13 is attached by press-fitting. However, the method of attaching the yoke 13 is not limited to this example. For example, adhesion using an adhesive, screwing a female screw formed on the radially inner surface of the rotor cylinder 12 with a male screw formed on the radially outer surface of the yoke cylinder 131, insert molding of the yoke 13 with the rotor lid 11 and the rotor cylinder 12, etc. may be used.

[0054] The magnets 14 are disposed between the circumferentially adjacent extension parts 1322 of the yoke 13 (step S3). For example, the magnets 14 are inserted between the circumferentially adjacent extension parts 1322 from one axial direction Da side toward the other axial direction Db and fixed. Alternatively, the magnets 14 may be inserted between the circumferentially adjacent extension parts 1322 from the radially inner side toward the radially outer side. The magnets 14 can be fixed by, for example, press fitting, bonding using an adhesive, brazing using silver solder, or the like.

[0055] With the above, the manufacturing method in FIG. 4 is completed, and the rotor 1 shown in FIG. 2 can be manufactured.

[0056] Note that step S3 may be performed between steps S1a and S2. That is, the manufacturing method of the rotor 1 may be performed in the order of steps S1a, S3, and S2. For example, in step S2, the yoke 13 in which the magnets 14 are arranged between the extension portions 1322 adjacent to each other in the circumferential direction may be attached to the inside of a covered cylindrical member constituted by the rotor lid portion 11 and the rotor cylinder portion 12.

[0057] Alternatively, steps S13a and S2 may be performed after step S3. That is, in the manufacturing method of the rotor 1, steps S11a, S12a, S3, S13a, and S2 may be performed in this order. For example, in step S3, the yoke 13 in the state shown in FIG. 5B may be attached to the inside of a covered cylindrical member formed by the rotor lid portion 11 and the rotor cylindrical portion 12. Then, each of the pillar portions 132a may be folded over onto the radially inner surface of the yoke cylindrical portion 131, so that the extension portions 1322 are arranged at intervals in the circumferential direction. Then, magnets 14 may be disposed between the extension portions 1322 adjacent to each other in the circumferential direction.

[0058] <1-5. Other manufacturing methods for rotor 1> Next, another example of a method for manufacturing the rotor 1 will be described with reference to Fig. 3 and Figs. 6 to 7C. Fig. 6 is a flow chart for explaining another example of a method for manufacturing the rotor 1. Figs. 7A to 7C are schematic diagrams showing another example of a manufacturing process for the yoke 13. Fig. 7A is a schematic diagram showing an example of a process for forming another plate-like member 13b from a plate-like magnetic body. Fig. 7B is a schematic diagram showing an example of a process for forming the yoke cylindrical portion 131 by bending the plate-like member 13b. Fig. 7C is a schematic diagram showing an example of a process for arranging the extension portion 1322 on the radially inner side surface of the yoke cylindrical portion 131 by folding and overlapping the column portion 132b.

[0059] First, in another manufacturing method of the rotor 1 shown in FIG. 6, step S1b for forming the yoke 13 is different from that in FIG.

[0060] 7A, a single plate-shaped member 13b is formed from a plate-shaped magnetic material by punching using a press (step S11b). The plate-shaped member 13b integrally includes a plate-shaped rectangular portion 131b and a plurality of pillar portions 132b. The plurality of pillar portions 132b protrude from one side of the outer edge of the rectangular portion 131b. Step S1b also includes step S11b. The plurality of pillar portions 132b are arranged at equal intervals in a direction perpendicular to the normal direction of the rectangular portion 131b and the direction in which the pillar portions 132b extend.

[0061] 7B, rectangular portion 131b is bent into a cylindrical shape around an axis (i.e., central axis CA) parallel to the extending direction (i.e., axial direction) of column portion 132b (step S12b). In this way, yoke cylindrical portion 131 is formed. Note that step S1b includes step S12b.

[0062] According to steps S11b and S12b, a single plate-like member 13b made of a plate-like magnetic material can be bent into a cylindrical shape by a simple and inexpensive process such as press working, etc. Therefore, the cylindrical yoke 13 in which the yoke cylindrical portion 131 and the protrusions 132 (pillar portions 132b in FIG. 7B) are integrally formed as a single member can be efficiently formed.

[0063] Thereafter, as shown in Fig. 7C, each pillar portion 132b is folded radially inward toward the other axial direction Db (step S13b). In detail, the pillar portion 132b is bent using its base (the other axial end portion of the pillar portion 132b in Fig. 7C) as a fulcrum to form the protrusion portion 132. The pillar portions 132b protrude from one axial end portion of the yoke cylindrical portion 131 and are arranged at intervals in the circumferential direction. Step S1b also includes step S13b.

[0064] According to step S13b, compared to a configuration in which the extension portion 1322 is formed on the radially inner surface of the yoke cylindrical portion 131 by cutting or the like, it is possible to provide a rotor 1 that can position the magnets 14 with a simpler and less expensive configuration, thereby improving the productivity of the rotor 1. In addition, it is possible to suppress or prevent the magnets 14 from being arranged at an angle when viewed from the radial direction, or the magnets 14 adjacent to each other in the circumferential direction from contacting each other.

[0065] Note that the subsequent steps in Fig. 6 (for example, steps S2 and S3) are the same as those in Fig. 4. Therefore, the description thereof will be omitted.

[0066] <2.Other> The embodiments of the present invention have been described above. Note that the scope of the present invention is not limited to the above-described embodiments. The present invention can be implemented by adding various modifications to the above-described embodiments without departing from the spirit of the invention. Furthermore, the matters described in the above-described embodiments can be appropriately combined in any manner as long as no contradiction occurs.

[0067] <3. Summary> The embodiments described thus far will be summarized below.

[0068] For example, the rotors disclosed herein may include: A rotor rotatable about a central axis extending in an axial direction, A yoke is a cylindrical magnetic body extending in an axial direction, and a plurality of magnets arranged in a circumferential direction are disposed on a radially inner surface of the yoke. The yoke is A cylindrical yoke portion extending in an axial direction; a plurality of protrusions connected to one axial end of the cylindrical yoke portion and arranged at intervals in a circumferential direction; having Each of the protrusions has a protrusion protruding radially inward from one axial end of the cylindrical yoke portion; an extension portion extending in the other axial direction along a radially inner side surface of the yoke cylindrical portion from a radially inner end portion of the protrusion; having The magnets are disposed between the extension portions adjacent to each other in the circumferential direction, The protrusion portion is configured to be integral with the yoke cylindrical portion as a single member (first configuration).

[0069] The rotor of the first configuration is as follows: The other axial end of the extension portion may be configured (second configuration) to be positioned on the other axial side of the one axial end of the yoke cylindrical portion and on the one axial side of the other axial end of the yoke cylindrical portion.

[0070] Also, the rotor of the first or second configuration has The axial length of the extension portion may be set to be equal to or greater than one-third of the axial width of the cylindrical yoke portion and equal to or less than the axial width of the cylindrical yoke portion (third configuration).

[0071] In addition, the rotor having any one of the first to third configurations has a rotor lid portion disposed on the other side of the axial direction from the protrusion portion and extending in a radial direction; a rotor cylinder portion extending in one axial direction from a radial outer end portion of the rotor lid portion; Further equipped with the rotor cylindrical portion surrounds the yoke cylindrical portion and is in contact with a radially outer surface of the yoke cylindrical portion, The rotor lid portion may be in contact with the other axial end portion of the yoke cylindrical portion (fourth configuration).

[0072] In addition, the rotor having any one of the first to fourth configurations is The radial thickness of the extension portion may be the same as the radial thickness of the yoke cylindrical portion (fifth configuration).

[0073] In addition, the rotor having any one of the first to fifth configurations is At least any one of the protruding portions may have a circumferential width smaller than a circumferential width of the extending portion (sixth configuration).

[0074] The motor disclosed in this specification also has The rotor has a configuration (seventh configuration) including a rotor having any one of the first to sixth configurations.

[0075] The method of manufacturing a rotor disclosed in the present specification further includes the steps of: A manufacturing method of a rotor, the rotor being rotatable about a central axis extending in an axial direction, the rotor having a plurality of axially extending extension portions arranged side by side at intervals in a circumferential direction on a radially inner surface of a cylindrical yoke portion extending in the axial direction, and a magnet being arranged between the extension portions adjacent to each other in the circumferential direction, the manufacturing method comprising the steps of: The eighth configuration includes a step of forming the extension portion by bending a plurality of pillar portions that protrude from one axial end of the yoke cylindrical portion and are arranged circumferentially at intervals, using the base of the pillar portions as a fulcrum.

[0076] A method for manufacturing a rotor of an eighth configuration includes the steps of: forming a single plate-like member from a plate-like magnetic material, the plate-like member including a disk portion having a central opening and the column portion protruding radially inward from an inner edge of the disk portion; forming the yoke cylindrical portion by drawing the disk portion into a cylindrical shape extending in a normal direction of the plate-like member; The configuration may further include the above (ninth configuration).

[0077] A method for manufacturing a rotor of an eighth configuration includes the steps of: forming a single plate-like member from a plate-like magnetic material, the plate-like rectangular portion and the column portion integrally including the plate-like rectangular portion and projecting from one side of an outer edge of the rectangular portion; forming the yoke cylindrical portion by bending the rectangular portion into a cylindrical shape about an axis parallel to an extension direction of the column portion; The tenth configuration may further include the above. [Industrial Applicability]

[0078] The present invention is useful for an apparatus having a rotor having a plurality of magnets arranged in the circumferential direction. [Explanation of symbols]

[0079] 100 motor, 101 shaft, 1 rotor, 11 rotor cover, 111 hole, 112 opening, 12 rotor cylinder, 13 yoke, 13a, 13b plate-shaped member, 131 yoke cylinder, 131a disc, 131b rectangular, 132 protrusion, 132a, 132b column 21 protrusion, 1322 extension, 14 magnet, 2 stator, 21 stator core, 22 insulator, 23 coil portion, 3 housing, 31 base portion, 32 holder cylinder portion, 321 bearing, 4 circuit board, CA central axis, Da one axial direction, Db the other axial direction

Claims

1. A rotor rotatable about a central axis extending in an axial direction, A yoke is a cylindrical magnetic body extending in an axial direction, and a plurality of magnets arranged in a circumferential direction are disposed on a radially inner surface of the yoke. The yoke is A cylindrical yoke portion extending in an axial direction; a plurality of protrusions connected to one axial end of the cylindrical yoke portion and arranged at intervals in a circumferential direction; having Each of the protrusions has a protrusion protruding radially inward from one axial end of the cylindrical yoke portion; an extension portion extending in the other axial direction along a radially inner side surface of the yoke cylindrical portion from a radially inner end portion of the protrusion; having The magnets are disposed between the extension portions adjacent to each other in the circumferential direction, The rotor, wherein the protrusion portion is integral with the yoke cylindrical portion as a single member.

2. The rotor according to claim 1 , wherein the other axial end of the extension is disposed on the other axial side of the one axial end of the cylindrical yoke portion and on the one axial side of the other axial end of the cylindrical yoke portion.

3. The rotor according to claim 1 , wherein the axial length of the extension portion is equal to or greater than one-third of the axial width of the cylindrical yoke portion and is equal to or smaller than the axial width of the cylindrical yoke portion.

4. a rotor lid portion disposed on the other side of the axial direction from the protrusion portion and extending in a radial direction; a rotor cylinder portion extending in one axial direction from a radial outer end portion of the rotor lid portion; Further equipped with the rotor cylindrical portion surrounds the yoke cylindrical portion and is in contact with a radially outer surface of the yoke cylindrical portion, The rotor according to claim 1 , wherein the other axial end of the cylindrical yoke portion is in contact with the rotor lid portion.

5. The rotor according to claim 1 , wherein a radial thickness of the extension portion is the same as a radial thickness of the cylindrical yoke portion.

6. The rotor according to claim 1 , wherein a circumferential width of at least any of the protrusions is smaller than a circumferential width of the extension.

7. A motor comprising a rotor according to any one of claims 1 to 6.

8. A manufacturing method of a rotor, the rotor being rotatable about a central axis extending in an axial direction, the rotor having a plurality of axially extending extension portions arranged side by side at intervals in a circumferential direction on a radially inner surface of a cylindrical yoke portion extending in the axial direction, and a magnet being arranged between the extension portions adjacent to each other in the circumferential direction, the manufacturing method comprising the steps of: A manufacturing method for a rotor comprising a step of forming the extension portion by bending a plurality of column portions that protrude from one axial end of the yoke cylindrical portion and are arranged circumferentially at intervals, using the base of the column portion as a fulcrum.

9. forming a single plate-like member from a plate-like magnetic material, the plate-like member including a disk portion having a central opening and the column portion protruding radially inward from an inner edge of the disk portion; forming the yoke cylindrical portion by drawing the disk portion into a cylindrical shape extending in a normal direction of the plate-like member; The method of claim 8 further comprising:

10. forming a single plate-like member from a plate-like magnetic material, the plate-like rectangular portion and the column portion integrally including the plate-like rectangular portion and projecting from one side of an outer edge of the rectangular portion; forming the yoke cylindrical portion by bending the rectangular portion into a cylindrical shape about an axis parallel to an extension direction of the column portion; The method of claim 8 further comprising:

Images