Rotor yoke, rotating electrical machine, and method for manufacturing rotor yoke

Abstract

To provide a rotor yoke, a rotary electric machine, and a manufacturing method for a rotor yoke that can reduce manufacturing costs while increasing the detection accuracy of a rotational position.SOLUTION: A rotor yoke 9 has a circumferential wall portion 14 surrounding a stator 3 and is rotatably supported about a rotation axis O with respect to the stator 3. The rotor yoke includes a plurality of reluctors 20 protruding radially outwardly from the circumferential wall portion 14 and arranged at circumferential intervals on an outer circumferential surface 14b of the circumferential wall portion 14. The reluctor 20 has a flattened portion 22 formed at a corner at least at the radially outer edge and having no cutting marks, and an end face 20d with cutting marks on the radial outer side.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a rotor yoke, a rotating electrical machine, and a method for manufacturing a rotor yoke.

Background Art

[0002] Conventionally, a rotating electrical machine (magnet generator) provided with a rotor yoke (flywheel) has been known. The rotor yoke has a peripheral wall portion (cylindrical portion) surrounding the stator. A plurality of reluctor are formed at equal intervals in the circumferential direction on the outer peripheral surface of the peripheral wall portion. On the other hand, magnets are provided on the inner peripheral surface of the peripheral wall portion. In this type of rotating electrical machine, the rotational position of the rotor yoke is detected by a pulse generator (signal generator) facing the reluctor in the radial direction of the rotor yoke. When the reluctor crosses in front of the pulse generator due to the rotation of the rotor yoke, a pulse signal (signal voltage) is generated from the pulse generator. The rotational position of the rotor yoke is detected using this pulse signal (see, for example, Patent Document 1).

[0003] As a method for manufacturing the reluctor, for example, press working may be performed. That is, the reluctor is formed to protrude on the outer peripheral surface of the peripheral wall portion by punching from the inner peripheral surface of the peripheral wall portion toward the outside in the radial direction. After that, in order to keep the distance between each of the plurality of reluctor and the pulse generator constant, cutting is performed on the end surface on the outer side in the radial direction of the reluctor. Thereby, the detection accuracy of the rotational position of the rotor yoke can be improved.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the above-described conventional technology, simply performing cutting on the end face on the radially outer side of the reluctor will cause burrs to occur at the corners of the reluctor. The burrs are generated when a part of the cutting piece plastically deforms and remains when the cutting edge separates from the corners of the reluctor. When burrs occur, the detection accuracy of the rotational position of the rotor yoke cannot be improved. In order to improve the detection accuracy, after performing cutting on the end face on the radially outer side of the reluctor, it is necessary to perform chamfering on the corners where burrs have occurred. Thus, there has been a problem that the manufacturing process of the reluctor is complicated and the manufacturing cost of the rotor yoke increases.

[0006] Therefore, the present invention provides a rotor yoke, a rotating electrical machine, and a method for manufacturing a rotor yoke that can reduce the manufacturing cost while enhancing the detection accuracy of the rotational position.

Means for Solving the Problems

[0007] In order to solve the above problems, a rotor yoke according to the present invention includes a peripheral wall portion surrounding the stator, a rotor yoke body rotatably supported around a rotation axis with respect to the stator, and a plurality of reluctors formed to protrude radially outward from the peripheral wall portion and arranged at intervals in the circumferential direction on the outer peripheral surface of the peripheral wall portion for generating a pulse signal for detecting the rotational position of the rotor yoke body. The reluctor has a tapered portion without a cutting mark and a flat surface with a cutting mark serving as the end face on the radially outer side, formed at least at the corners of the radially outer end portion and at least at a location corresponding to at least one of the corners. The tapered portion is inclined so that the reluctor tapers as it goes radially outward, or is curved so as to be convex outward.

[0008] The manufacturing method of a rotor yoke according to the present invention is a manufacturing method of a rotor yoke having a peripheral wall portion surrounding the stator and rotatably supported around a rotation axis with respect to the stator, in which a plurality of reluctor are formed. In the method, a pressing process is performed on the peripheral wall portion to project the reluctor radially outward from the peripheral wall portion, and a tapered portion is formed at least at a corner portion at the radially outer end portion and at a location corresponding to at least one of the corner portions. After the pressing process, a cutting edge is fed so that the tapered portion is on the downstream side in the feed direction, and a cutting process is performed to cut the radially outer end portion of the reluctor while leaving the tapered portion. In the pressing process, the tapered portion is formed to be inclined so that the reluctor tapers as it goes radially outward, or is formed to be curved so as to be convex outward.

Effects of the Invention

[0009] According to the present invention, since cutting is performed on the radially outer end portion of the reluctor having a chamfered portion, sufficient mechanical strength of the corner portion of the reluctor can be ensured, and the generation of burrs during cutting can be prevented. Therefore, it is possible to reduce the manufacturing cost of the rotor yoke while improving the rotational position detection accuracy of the rotor yoke by the pulse generator.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0011] Next, embodiments of the present invention will be described with reference to the drawings.

[0012] <Rotating electrical machine> FIG. 1 is a cross-sectional view of a rotating electrical machine 1. The rotating electrical machine 1 is used, for example, in a motorcycle and can function as a generator or a starter motor.

[0013] As shown in FIG. 1, the rotating electrical machine 1 includes, for example, a shaft 2 integrated with a crankshaft (not shown), a stator 3 disposed coaxially with the shaft 2 and fixed to an engine block (not shown), and a rotor 4 formed to cover the periphery of the stator 3 and fixed to the shaft 2. In the following description, the rotation direction of the shaft 2 (rotor 4) is referred to as the "circumferential direction", and the radial direction of the shaft 2 orthogonal to the rotation axis O and the circumferential direction of the shaft 2 is simply referred to as the "radial direction" for explanation.

[0014] <Stator> The stator 3 has a stator core 5 fixed to an engine block (not shown). The stator core 5 is formed by laminating, for example, a plate material such as an electromagnetic steel sheet in the direction of the rotation axis O. However, it is not limited thereto, and for example, it may be formed by pressure molding soft magnetic powder. The stator core 5 has an annular core body 5a.

[0015] A through hole 5b for avoiding interference with the shaft 2 and the rotor 4 is formed at the radial center of the core body 5a. Further, a plurality of bolt insertion holes 5c are formed around the through hole 5b in the circumferential direction in the core body 5a. Bolts 18 are inserted into these bolt insertion holes 5c, and the stator core 5 is fastened and fixed to an engine block (not shown).

[0016] A plurality of teeth 6 protruding radially outward are provided side by side in the circumferential direction on the outer peripheral portion of the core body 5a. An insulating insulator 7 is provided to cover the periphery of each tooth 6. A coil 50 is wound around each tooth 6 from above the insulator 7.

[0017] <Rotor> FIG. 2 is a plan view of the rotor 4 as viewed from the stator 3 side. As shown in FIGS. 1 and 2, the rotor 4 includes a base portion 8 formed in a disk shape, and a rotor yoke 9 fixed to the stator 3 side (the left side in FIG. 2) of the base portion 8. At substantially the center in the radial direction of the base portion 8, a cylindrical boss portion 10 protrudes toward the stator 3 side. A through hole 10a into which the shaft 2 is inserted is formed at the center in the radial direction of the boss portion 10.

[0018] A key groove 10b is formed in the through hole 10a. On the other hand, a key (not shown) that engages with the key groove 10b is provided on the shaft 2. Thereby, the base portion 8 and the shaft 2 are connected so as not to be relatively rotatable. Then, by fastening a nut or the like (not shown) to the tip of the shaft 2, the base portion 8 is fixed to the shaft 2. In addition, a plurality of insertion holes 11 are formed around the boss portion 10 in the base portion 8. The plurality of insertion holes 11 are arranged at equal intervals in the circumferential direction. These insertion holes 11 are formed to penetrate the base portion 8 in the thickness direction. The rotor yoke 9 is fixed to the base portion 8 by inserting rivets 12 into the insertion holes 11.

[0019] The rotor yoke 9 is formed by, for example, performing press working on a metal plate made of a magnetic material. The rotor yoke 9 is formed in a bottomed cylindrical shape so as to cover the stator 3 from the base portion 8 side. The rotor yoke 9 has a bottom wall portion 13 and a peripheral wall portion 14 that is bent and extended along the direction of the rotation axis O from the outer peripheral edge of the bottom wall portion 13 to the side opposite to the base portion 8.

[0020] A through hole 13a is formed at the center in the radial direction in the bottom wall portion 13. The boss portion 10 and the shaft 2 of the base portion 8 are inserted into the through hole 13a. In addition, through holes 15 that penetrate in the thickness direction are formed in the bottom wall portion 13 at positions corresponding to the insertion holes 11 of the base portion 8. The rivet 12 is inserted into each insertion hole 11, 15, and the tip of the rivet 12 is buckled and deformed, whereby the rotor yoke 9 is fixed to the base portion 8. The rotor yoke 9 fixed to the base portion 8 rotates around the rotation axis O with respect to the stator 3.

[0021] The peripheral wall portion 14 surrounds the stator 3. A plurality of magnets 16 magnetized in a plurality of poles are provided on the inner peripheral surface 14a of the peripheral wall portion 14 so that the magnetic poles change in order in the circumferential direction. As the magnet 16, for example, a ferrite magnet is used. However, the present invention is not limited to this, and rare earth magnets can also be used. The magnet 16 is covered with a magnet cover 17. The magnet cover 17 is formed so as to cover the inner peripheral surface of the magnet 16 from the opening of the rotor yoke 9.

[0022] Further, a plurality of reluctor 20 are formed to project on the outer peripheral surface 14b side of the peripheral wall portion 14. Each reluctor 20 is arranged at equal intervals in the circumferential direction on the outer peripheral surface 14b of the peripheral wall portion 14. The reluctor 20 is for detecting the rotation position of the rotor yoke 9 that rotates integrally with the shaft 2, and for detecting the ignition timing of the engine and the like. The reluctor 20 is used together with a pulse generator 30 described later. Hereinafter, the reluctor 20 will be described in detail.

[0023] FIG. 3 is an enlarged view of part A of FIG. 1. FIG. 4 is an enlarged view of part B of FIG. 2. As shown in FIGS. 3 and 4, the reluctor 20 is formed by subjecting the peripheral wall portion 14 to press working so that the peripheral wall portion 14 projects radially outward from the inner peripheral surface 14a. That is, a recess 21 is formed on the inner peripheral surface 14a of the peripheral wall portion 14 by an amount corresponding to the projection of the reluctor 20 radially outward. Details of the manufacturing method of the reluctor 20 (rotor yoke 9) will be described later.

[0024] The shape of the reluctor 20 protruding from the outer peripheral surface 14b of the peripheral wall portion 14 is substantially rectangular parallelepiped. More specifically, both circumferential side surfaces 20a (hereinafter referred to as circumferential side surfaces 20a) of the reluctor 20 in the circumferential direction and both side surfaces 20b (hereinafter referred to as axial side surfaces 20b) of the reluctor 20 in the direction of the rotation axis O have a certain amount of draft required during press working and are substantially orthogonal to the rotation axis O.

[0025] The axial side surface 20b and the radially outer end surface 20d of the reluctor 20 are connected by a chamfering portion 22. In other words, the chamfering portion 22 is formed flat as if chamfering is performed at the corner between the end surface 20d and the axial side surface 20b of the reluctor 20. That is, the chamfering portions 22 face each other in the direction of the rotation axis O. On the other hand, chamfering is not performed at both circumferential ends of the reluctor 20. The corner portions 20c at both circumferential ends of the reluctor 20 are sharp. Also, the end surface 20d of the reluctor 20 is formed flat.

[0026] <Pulse generator> Returning to FIG. 1, the pulse generator 30 is arranged so as to face the reluctor 20 in the radial direction. When the corner portion of the reluctor 20 crosses the pulse generator 30, a pulse signal (rectangular wave of positive voltage pulse and negative voltage pulse) is generated from the pulse generator 30. The pulse generator 30 outputs the generated pulse signal to a control unit (such as a CDI unit) not shown. The control unit can obtain various information such as the engine rotation speed information, the rotation angle information of the shaft 2, and the rotation position of the rotor yoke 9 by receiving the pulse signal.

[0027] For example, the ignition timing of the engine of a motorcycle is controlled based on the engine rotation speed information and the rotation angle information of the shaft 2 obtained by the reluctor 20 and the pulse generator 30. More specifically, by looking at the midpoint between the rising edge and the falling edge in the pulse waveform (rectangular waveform) emitted from the pulse generator 30, the above-mentioned various information is acquired.

[0028] In order to improve the detection accuracy by a control unit (not shown), it is necessary to make the circumferential width of the reluctor 20 narrower. Further, among the corners of the reluctor 20, the corners crossing the pulse generator 30, that is, the corners formed at both circumferential ends of the reluctor 20, are preferably as sharp as possible. By configuring in this way, the disturbance of the pulse waveform generated by the pulse generator 30 can be suppressed. Since the disturbance of the pulse waveform is suppressed, the rising edge and the falling edge in the pulse waveform can be made prominent. For this reason, the detection accuracy by a control unit (not shown) can be enhanced. Since the corners 20c at both circumferential ends of the reluctor 20 are sharp, the detection accuracy by a control unit (not shown) can be enhanced.

[0029] <Operation of the rotating electrical machine> Next, the operation of the rotating electrical machine 1 will be described. When the engine of the motorcycle is started, the crankshaft is rotated. The shaft 2 and the rotor 4 are rotated integrally with this crankshaft. Then, the magnetic flux amount of the magnet 16 changes with respect to the coil 50 wound around the stator 3. This change in the magnetic flux amount becomes an electromotive force and a current is generated in the coil 50. The current generated in the coil 50 is stored in, for example, a battery (not shown) or supplied to attached electrical equipment (not shown).

[0030] When the rotating electrical machine 1 functions as a starter motor, current is selectively supplied to a predetermined coil 50. In this case, magnetic flux is formed in each tooth 6 of the stator 3, and a magnetic attractive force and a repulsive force are generated between this magnetic flux and the magnet 16 of the rotor yoke 9. As a result, the rotor 4 is continuously rotated, and further the crankshaft (not shown) is rotated. At this time, the ignition timing of the engine is detected by the above-described pulse generator 30, and the engine is ignited at an appropriate timing. Then, the engine is started.

[0031] <Manufacturing method of the rotor yoke> Next, a manufacturing method of the rotor yoke 9 will be described with reference to FIGS. 3 and 5. FIG. 5 is an explanatory view showing a manufacturing method of the reluctor 20 in the rotor yoke 9. As shown in FIGS. 3 and 5, the metal plate is pressed to form a bottomed cylindrical shape, thereby forming the outer shape of the rotor yoke 9. At this time, a part of the peripheral wall portion 14 in the rotor yoke 9 is pushed out radially outward from the inner peripheral surface 14a by pressing. Then, a reluctor 20 protruding radially outward from the outer peripheral surface 14b of the peripheral wall portion 14 is formed (pressing step).

[0032] As shown in FIG. 5(a), when the reluctor 20 is formed to protrude from the outer peripheral surface 14b of the peripheral wall portion 14 by pressing, flat portions 22 are formed on both sides in the direction of the rotation axis O at the radially outer end portion of the reluctor 20. That is, the flat portions 22 are formed by pressing. Subsequently, for example, by using a lathe or the like, the rotor yoke 9 is rotated around the rotation axis O. Then, the radially outer end portion of the reluctor 20 is cut by a cutting edge 40 (cutting step). The feed direction D of the cutting edge 40 is in the direction of the rotation axis O.

[0033] As shown in FIGS. 5(b) to 5(d), in the cutting step, the protruding height from the outer peripheral surface 14b of the reluctor 20 is made uniform. At this time, the flat portion 22 is positioned at the corner portion on the downstream side in the feed direction D of the cutting edge 40 at the radially outer end portion of the reluctor 20. By forming the flat portion 22, the mechanical strength of the corner portion of the reluctor 20 is sufficiently ensured. For this reason, the shearing force is transmitted to the cutting piece Cp, the generation of burrs during cutting is prevented, and the cutting piece Cp is surely cut (see FIG. 5(d)).

[0034] By the cutting step, a flat end face 20d is formed at the radially outer end portion of the reluctor 20. There are cutting marks on the end face 20d formed by the cutting step. On the other hand, there are no cutting marks on the flat portion 22 formed by pressing.

[0035] Here, the size of the flat portion 22 formed in the pressing process is such that the flat portion 22 remains even when the machining allowance of the reluctor 20 is the largest. Therefore, during the cutting process, the mechanical strength of the corners of the reluctor 20 can be ensured reliably. The case where the machining allowance of the reluctor 20 is the largest means the case where the protruding height from the outer peripheral surface 14b of the reluctor 20 formed in the pressing process is the maximum tolerance.

[0036] Also, the protruding height from the outer peripheral surface 14b of the reluctor 20 formed in the pressing process and the size of the flat portion 22 are such that the effective width in the circumferential direction of the end face 20d can be ensured even when the machining allowance of the reluctor 20 is the smallest. Therefore, the pulse generator 30 can surely generate a pulse waveform. The case where the machining allowance of the reluctor 20 is the smallest means the case where the protruding height from the outer peripheral surface 14b of the reluctor 20 formed in the pressing process is the minimum tolerance.

[0037] As described above, in the above-described embodiment, the rotor yoke 9 includes a peripheral wall portion 14 and a plurality of reluctor 20s that protrude radially outward from the outer peripheral surface 14b of the peripheral wall portion 14 and are arranged at equal intervals in the circumferential direction. A flat portion 22 is formed at the corner of the end face 20d and the axial side face 20b of the reluctor 20. Since the flat portion 22 is formed in the pressing process, there are no cutting marks. On the other hand, since the end face 20d is formed in the cutting process, there are cutting marks.

[0038] Thus, since the flat portion 22 is inclined with respect to the radially outer end of the reluctor 20 to be cut later, it is possible to sufficiently ensure the mechanical strength at the corner of the reluctor 20 where the flat portion 22 is formed. Therefore, when feeding the cutting edge 40 during the cutting process, by positioning the flat portion 22 on the downstream side in the feeding direction D of the cutting edge 40, a shearing force is transmitted to the cutting piece Cp and the cutting piece Cp can be surely cut. As a result, the generation of burrs during cutting can be prevented. Thus, the rotational position detection accuracy of the rotor yoke 9 by the pulse generator 30 can be improved. Since the chamfering process for removing burrs can be reduced, the manufacturing cost of the rotor yoke 9 can be reduced.

[0039] The flat portions 22 face each other in the direction of the rotation axis O, and this direction of the rotation axis O becomes the feeding direction D of the cutting edge 40. Therefore, the corners 20c at both circumferential ends of the reluctor 20 can be sharpened. As a result, when the reluctor 20 crosses in front of the pulse generator 30 due to the rotation of the rotor yoke 9, the disturbance of the pulse waveform generated from the pulse generator can be suppressed. That is, the rising edge and the falling edge in the pulse waveform can be made prominent. Thus, the rotational position detection accuracy of the rotor yoke 9 by the pulse generator 30 can be further improved.

[0040] As a manufacturing method of the rotor yoke 9, it has a pressing process of protruding the reluctor 20 radially outward from the peripheral wall portion 14 of the rotor yoke 9 and forming the flat portion 22 on the reluctor 20. After this pressing process, it has a cutting process of cutting the radially outer end of the reluctor 20 to form the end face 20d of the reluctor 20. Therefore, before cutting the radially outer end of the reluctor 20, it is possible to sufficiently ensure the mechanical strength of the corner of the reluctor 20 located on the downstream side in the feeding direction D of the cutting edge 40. As a result, a shearing force is transmitted to the cutting piece Cp and the cutting piece Cp can be surely cut. Therefore, the generation of burrs during cutting can be prevented. Thus, the rotational position detection accuracy of the rotor yoke 9 by the pulse generator 30 can be improved. Since the chamfering process for removing burrs can be reduced, the manufacturing cost of the rotor yoke 9 can be reduced.

[0041] The planar chamfering portion 22 faces each other in the direction of the rotation axis O, and the direction of the rotation axis O becomes the feed direction D of the cutting edge 40. Therefore, burrs do not occur at the corner portions 20c at both circumferential ends of the reluctor 20, and the corner portions 20c can be sharpened. Thus, the rotational position detection accuracy of the rotor yoke 9 by the pulse generator 30 can be further improved.

[0042] While enhancing the detection accuracy of the rotational position of the rotating electrical machine 1, the manufacturing cost of the rotor yoke 9 can be reduced, so that it is possible to contribute to Goal 7 of the Sustainable Development Goals (SDGs) led by the United Nations, "Ensure access for all people to affordable, reliable and sustainable modern energy", and Goal 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation".

[0043] Note that the present invention is not limited to the above-described embodiments, and includes those obtained by making various modifications to the above-described embodiments without departing from the gist of the present invention. For example, in the above-described embodiment, the rotating electrical machine 1 has been described for the case where it is used in, for example, a motorcycle. However, it is not limited thereto, and it can be used in various devices as a generator. When functioning as a generator or a starter motor, the rotating electrical machine 1 can also be used in an automobile.

[0044] In the above-described embodiment, the case where the planar chamfering portion 22 is formed flat as if chamfering is performed at the corner between the end face 20d and the axial side face 20b of the reluctor 20 has been described. The case where the planar chamfering portion 22 faces each other in the direction of the rotation axis O has been described. However, it is not limited thereto, and it is sufficient that a tapered portion is formed at least at the corner portion at the radially outer end of the reluctor 20 and at a location corresponding to at least one of the corner portions. The tapered portion refers to a portion that is inclined so that the reluctor 20 tapers as it goes radially outward, or is curved so as to protrude outward. This will be specifically described below.

[0045] That is, the reluctor 20 tapers radially outward by the planar machining portion 22. That is, the planar machining portion 22 is an example of a tapered portion formed so that the reluctor 20 tapers as it goes radially outward. Instead of the planar machining portion 22, the entire axial side surface 20b of the reluctor 20 may be inclined or curved so as to be convex outward. Even in such a configuration, in the reluctor 20, the mechanical strength of the corner portion on the downstream side in the feed direction D of the cutting edge 40 can be sufficiently ensured. "Convex outward" means convex outward in the direction of the rotation axis O when a tapered portion is formed on the axial side surface 20b.

[0046] When a tapered portion is formed only at the corner portion of the reluctor 20, it may be a rounded machining portion instead of the planar machining portion 22. This rounded machining portion may also be formed so as to be convex outward. The rounded machining portion does not necessarily have to be an arc shape and may be curved. Even in such a configuration, the mechanical strength at the corner portion of the reluctor 20 can be sufficiently ensured.

[0047] Also, the planar machining portion 22 does not have to be formed at both corner portions of the end face 20d and the axial side surface 20b of the reluctor 20. It may be formed at least at either one of both corner portions of the end face 20d and the axial side surface 20b of the reluctor 20. In this case, the location where the planar machining portion 22 is formed may be the downstream side in the feed direction D of the cutting edge 40.

[0048] Also, the planar machining portion 22 may be formed at the corner portion of the end face 20d and the circumferential side surface 20a of the reluctor 20. In this case, the feed direction D of the cutting edge 40 may be set to the circumferential direction corresponding to the formation location of the planar machining portion 22. In this case, in the cutting process, for example, a milling machine or the like can be used instead of a lathe. Even in such a configuration, the manufacturing cost of the rotor yoke 9 can be reduced by the amount of reducing the process of removing burrs. The same can be said when a tapered portion is formed on the entire circumferential side surface 20a of the reluctor 20.

Explanation of reference numerals

[0049] 1...Rotating electric machine, 2...Shaft, 3...Stator, 4...Rotor, 5...Stator core, 5a...Core body, 5b...Through hole, 5c...Bolt insertion hole, 6...Teeth, 7...Insulator, 8...Base portion, 9...Rotor yoke, 10...Boss portion, 10a...Through hole, 10b...Key groove, 11...Insertion hole, 12...Rivet, 13...Bottom wall portion, 13a...Through hole, 14...Peripheral wall portion, 14a...Inner peripheral surface, 14b...Outer peripheral surface, 15...Insertion hole, 16...Magnet, 17...Magnet cover, 18...Bolt, 20...Reluctor, 20a...Circumferential side surface, 20b...Axial side surface, 20c...Corner portion, 20d...End face, 21...Recessed portion, 22...Flattening portion, 30...Pulse generator, 40...Cutting edge, 50...Coil

Claims

1. A rotor yoke body having a peripheral wall portion surrounding the stator and rotatably supported about a rotation axis with respect to the stator, a plurality of reluctor portions that project radially outward from the peripheral wall portion, are arranged at intervals in the circumferential direction on the outer peripheral surface of the peripheral wall portion, and generate a pulse signal for detecting the rotational position of the rotor yoke body, and comprising: The reluctor portions are formed at least at a corner portion at the radially outer end portion and at a location corresponding to at least one of the corner portions, and having a tapered portion without cutting marks, and a flat surface having cutting marks formed in a predetermined direction that is the radially outer end surface, and having: The tapered portion is inclined so that the reluctor tapers as it goes radially outward, or is curved so as to be convex outward, The tapered portion is formed so as to connect between the side surface of the reluctor in the predetermined direction and the flat surface. A rotor yoke characterized by the above.

2. The rotor yoke according to claim 1, wherein the tapered portion is a chamfered portion formed at a corner portion at the radially outer end portion of the reluctor and at both ends of the reluctor in the rotation axis direction.

3. The rotor yoke according to claim 1 or claim 2, a magnet disposed on the inner peripheral surface of the peripheral wall portion in the rotor yoke, and a stator disposed radially inside the rotor yoke and having a plurality of coils wound thereon. A rotating electrical machine characterized by the above.

4. In a method for manufacturing a rotor yoke in which a plurality of reluctor portions are formed on a rotor yoke body having a peripheral wall portion surrounding the stator and rotatably supported about a rotation axis with respect to the stator, Perform pressing on the peripheral wall portion, project a reluctor radially outward from the peripheral wall portion, and form a tapered portion at a corner at least at the radially outer end portion and at a location corresponding to at least one of the corners. A pressing process; After the pressing process, feed a cutting edge so that the tapered portion is on the downstream side in the feed direction, and cut the radially outer end portion of the reluctor while leaving the tapered portion. A cutting process; In the pressing process, the tapered portion is formed to be inclined so that the reluctor tapers as it goes radially outward, or is formed to be curved so as to be convex outward. A method for manufacturing a rotor yoke, characterized by the above.

5. In the pressing process, chamfered portions as the tapered portions are formed at corners at the radially outer end portion of the reluctor and at both ends in the axial direction of the reluctor. The method for manufacturing a rotor yoke according to claim 4, characterized by this.

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