WO2012033202A1 - Arched magnet and magnetic field molding die - Google Patents

Arched magnet and magnetic field molding die Download PDF

Info

Publication number
WO2012033202A1
WO2012033202A1 PCT/JP2011/070631 JP2011070631W WO2012033202A1 WO 2012033202 A1 WO2012033202 A1 WO 2012033202A1 JP 2011070631 W JP2011070631 W JP 2011070631W WO 2012033202 A1 WO2012033202 A1 WO 2012033202A1
Authority
WO
WIPO (PCT)
Prior art keywords
magnet
arcuate
magnetic
arcuate magnet
curved surface
Prior art date
Application number
PCT/JP2011/070631
Other languages
French (fr)
Japanese (ja)
Inventor
一彦 宮城島
貞雄 二橋
Original Assignee
Tdk株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tdk株式会社 filed Critical Tdk株式会社
Priority to CN201180043091.1A priority Critical patent/CN103098354B/en
Publication of WO2012033202A1 publication Critical patent/WO2012033202A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
    • H02K15/02—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies
    • H02K15/03—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies having permanent magnets
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
    • H01F41/0273—Imparting anisotropy

Definitions

  • the present invention relates to an arc-shaped arcuate magnet and a magnetic field molding die.
  • the arcuate magnet has an arc shape and is used for a rotor or a stator of an electric motor.
  • Patent Document 1 when manufacturing a ferritic magnet having an arc shape and anisotropy in the radial direction, by using a dry molding apparatus provided with an orientation ferromagnetic material, the anisotropy direction is in the radial direction. Is obtained.
  • Patent Document 1 also describes that the cogging torque and torque ripple of the motor are reduced by defining the surface magnetic flux density of the anisotropic ferrite magnet.
  • arcuate magnets magnetized on one pole are alternately arranged with N and S poles in the circumferential direction of the rotor or stator.
  • an arcuate magnet whose dimension in the circumferential direction is larger than an arcuate magnet magnetized to one pole may be used by magnetizing to two poles. In this way, the number of arcuate magnets used in one electric motor can be reduced.
  • the anisotropic direction is aligned in the radial direction and only two poles are magnetized, one arcuate magnet is attached.
  • Patent Document 1 does not disclose or suggest this point, and there is room for improvement.
  • An object of the present invention is to suppress a decrease in magnetic flux density that can be effectively used in an arcuate magnet magnetized on a plurality of poles.
  • a sintered magnet according to the present invention is a magnet including a plurality of magnetic powder particles, and in the cross section cut by a plane orthogonal to the length direction of the magnet, the plurality of magnetic powder particles are The orientation direction of the easy axis of magnetization is oriented so as to focus on at least two points.
  • the arcuate magnet has a circular cross section cut by a plane orthogonal to the length direction, and the orientation direction of the easy axis of the plurality of magnetic particle particles is converged to at least two points in the cross section. And is magnetized to the same number of poles as the number of converging points. By doing in this way, magnetic flux can be concentrated from this arcuate magnet toward the teeth of the electric motor facing this. As a result, this arcuate magnet can suppress a decrease in magnetic flux density that can be effectively used in an arcuate magnet magnetized on a plurality of poles, and an arcuate magnet magnetized on one pole alternately with N and S poles. Compared with the case where it arranges, the magnetic flux density which a tooth can utilize can be made equivalent or more.
  • the arcuate magnet when the arcuate magnet is magnetized with one pole, the arcuate magnet is arranged so that the cross-sectional shape of the arcuate magnet is an arc-shaped first curved surface and the outside of the first curved surface.
  • the waveform of the magnetic flux density on at least one of the second curved surface having a circular arc shape in the cross section has a peak as many as the number of points where the orientation directions converge.
  • the absolute value of the difference between the peak and the minimum value of the waveform is preferably 5% or more of the absolute value of the minimum value.
  • a magnetic field molding die includes a mold frame, a first punch, and a second punch, and includes the mold frame, the first punch, and the second punch.
  • both the first punch and the second punch have the nonmagnetic material
  • at least one of the ferromagnetic materials protrudes toward the nonmagnetic material at a portion in contact with the nonmagnetic material. It has at least two convex parts.
  • the ferromagnetic material in contact with the nonmagnetic material is directed to the nonmagnetic material at a portion in contact with the nonmagnetic material. And at least two convex portions projecting.
  • the present invention can suppress a decrease in magnetic flux density that can be effectively used in an arcuate magnet magnetized on a plurality of poles.
  • FIG. 1 is a perspective view showing an example of an arcuate magnet according to the present embodiment.
  • FIG. 2 is a cross-sectional view showing a state in which the bow-shaped magnet according to this embodiment is cut by a plane orthogonal to the length direction.
  • FIG. 3 is a cross-sectional view showing the orientation direction of the easy axis of magnetic powder particles in the cross section of the bow magnet according to the present embodiment.
  • FIG. 4 is a diagram for explaining magnetization.
  • FIG. 5 is a schematic diagram showing a state in which the bow magnet according to the present embodiment is magnetized.
  • FIG. 6 is a diagram showing the relationship between the arcuate magnet magnetized one pole at a time and the teeth of the electric motor.
  • FIG. 1 is a perspective view showing an example of an arcuate magnet according to the present embodiment.
  • FIG. 2 is a cross-sectional view showing a state in which the bow-shaped magnet according to this embodiment is cut by a plane orthogonal to the length direction.
  • FIG. 3
  • FIG. 7 is a diagram showing a relationship between a bow magnet magnetized with two poles and teeth of an electric motor.
  • FIG. 8 is an explanatory diagram of a method for measuring the surface magnetic flux density of an arcuate magnet.
  • FIG. 9 is an explanatory diagram of a method for measuring the surface magnetic flux density of an arcuate magnet.
  • FIG. 10 is a diagram showing a waveform of the surface magnetic flux density when the arcuate magnet according to the present embodiment is magnetized with one pole.
  • FIG. 11 is a diagram showing a waveform of the surface magnetic flux density when an arcuate magnet having the same size and shape as the arcuate magnet according to the present embodiment is radially oriented and magnetized with one pole.
  • FIG. 12 is a diagram showing a waveform of the surface magnetic flux density in another example when the arcuate magnet according to the present embodiment is magnetized with one pole.
  • FIG. 13 is an explanatory diagram of a magnetic field shaping apparatus for shaping a bow magnet according to the present embodiment.
  • FIG. 14 is an explanatory view showing a molding die included in the magnetic field molding apparatus according to the present embodiment.
  • FIG. 15 is an explanatory view showing a modification of the molding die required for the magnetic field molding apparatus according to the present embodiment.
  • FIG. 16 is an explanatory view showing another method for manufacturing the bow magnet according to the present embodiment.
  • FIG. 17 is an explanatory view showing another method for manufacturing the bow magnet according to the present embodiment.
  • FIG. 1 is a perspective view showing an example of an arcuate magnet according to the present embodiment.
  • FIG. 2 is a cross-sectional view showing a state in which the bow-shaped magnet according to this embodiment is cut by a plane orthogonal to the length direction.
  • the arcuate magnet 10 has an arch shape as a whole.
  • the arcuate magnet 10 is divided into a first curved surface 11, a second curved surface 12 disposed on the outer side 11 o of the first curved surface 11, opposite to the first curved surface 11, and the first curved surface 11 and the second curved surface 12. And a side surface 13 to be connected.
  • the arcuate magnet 10 has a plurality of, more specifically, four side surfaces 13A, 13B, 13C, and 13D.
  • Each of the side surfaces 13A, 13B, 13C, and 13D is a plane and is orthogonal to each other. In the present embodiment, there are four side surfaces 13, but the number of side surfaces is not limited to this.
  • the boundary between the side surfaces 13B and 13D and the first curved surface 11 may be chamfered to provide six side surfaces 13, or the boundary between the side surfaces 13B and 13D and the second curved surface 12 may be chamfered to provide six side surfaces 13. It may be.
  • the first curved surface 11 or the second curved surface 12 is a part of a cylinder centering on predetermined axes Za and Zb, respectively.
  • the shape of the first curved surface 11 and the second curved surface is an arc shape, that is, a shape of a part of a circle when cut by a plane orthogonal to the axes Za and Zb.
  • the axes Za and Zb are the same, and the curvature radius ra of the first curved surface 11 and the curvature radius rb of the second curved surface 12 are different (ra ⁇ rb).
  • the axes Za and Zb may be different.
  • the first curved surface 11 and the second curved surface 12 may have the same or different curvature radii.
  • the length direction of the arcuate magnet 10 is a direction parallel to the axis Za or the axis Zb that is the center of the first curved surface 11 or the second curved surface 12. This is orthogonal to the curved surface of the first curved surface 11 or the curved surface of the second curved surface 12, that is, the direction along R (the direction indicated by the arrow C in FIG. 1), and the curved surface of the first curved surface 11 or the second curved surface 12.
  • the direction is parallel to the curved surface.
  • the length direction can be said to be a direction parallel to a boundary line BL between the side surfaces 13B and 13D having a rectangular planar shape and the first curved surface 11 or the second curved surface 12.
  • a cross section obtained by cutting the arcuate magnet 10 along a plane perpendicular to the length direction is referred to as a transverse cross section of the arcuate magnet 10.
  • the shape in the cross section of the 1st curved surface 11 and the 2nd curved surface 12 is circular arc shape.
  • a direction perpendicular to the length direction is referred to as a width direction, and a circumferential direction of a circle centering on the axis Za or the axis Zb shown in FIG. 2 and passing through the arcuate magnet 10 is referred to as a circumferential direction of the arcuate magnet 10.
  • the dimension of the arcuate magnet 10 in the length direction is referred to as the length of the arcuate magnet 10 (reference numeral L), and the maximum dimension of the arcuate magnet 10 in the width direction is referred to as the width of the arcuate magnet 10 (reference numeral W).
  • the arcuate magnet 10 as a whole has an arch shape, and the cross-sectional shape is an arc shape, a C shape, or a fan shape.
  • the arcuate magnet 10 is also called a segment-type magnet (segment magnet), and is used, for example, for a stator (stator) or a rotor (rotor) of an electric motor.
  • the application target of the bow magnet 10 is not limited to the electric motor.
  • the bow magnet 10 can be widely applied to permanent magnets used in speakers, microphones, magnetron tubes, magnetic field generators for MRI, ABS sensors, fuel / oil level sensors, distributor sensors, magnet clutches, and the like.
  • the arcuate magnet 10 is a ferrite sintered magnet.
  • the sintered ferrite magnet is obtained by sintering a plurality of ferrite magnetic particles. Ferrite sintered magnets are widely used because they have relatively high magnetic properties and are inexpensive.
  • the kind of sintered ferrite magnet is not particularly limited, and may be any of barium-based, strontium-based, calcium-based and the like.
  • the manufacturing method of the arcuate magnet 10 may be either a wet manufacturing method or a dry manufacturing method, and the manufacturing method is not limited.
  • the type of the arcuate magnet 10 is not limited to a ferrite sintered magnet, and may be a sintered metal magnet such as a rare earth sintered magnet or a samarium / cobalt sintered magnet.
  • the arcuate magnet 10 may be a bonded magnet in which magnetic powder particles are hardened with resin or rubber.
  • the arcuate magnet 10 according to the present embodiment is intended for all magnets including a plurality of magnetic powder particles obtained by molding a plurality of magnetic powder particles.
  • FIG. 3 is a cross-sectional view showing the orientation direction of the easy axis of magnetization of the magnetic particle in the cross section of the bow magnet according to the present embodiment.
  • 3 indicates the orientation direction of the magnetic powder particles CPm
  • CL indicates the center of the arcuate magnet 10 in the width direction (the same applies hereinafter).
  • FIG. 4 is a diagram for explaining magnetization.
  • FIG. 5 is a schematic diagram showing a state in which the bow magnet according to the present embodiment is magnetized.
  • the arcuate magnet 10 is oriented so that the easy axes of the plurality of magnetic powder particles CPm converge toward at least two axes Zca and Zcb. That is, as shown in FIG.
  • the arcuate magnet 10 has a plurality of magnetic powder particles CPm in which the orientation direction of the easy magnetization axis is at least two points (two axes Zca and Zcb and the cross section) as shown in FIG. Is oriented to converge at the intersection of
  • the magnetic powder particles are hardened into the shape of the arched magnet 10, the magnetic powder particles are oriented so that the easy axis of magnetization is focused toward at least two axes Zca and Zcb by forming the magnetic powder particles while being molded in a magnetic field (magnetic field shaping). Orient the CPm. This magnetic field shaping method will be described later.
  • the portion where the orientation direction of the easy magnetization axis of the magnetic powder particles converges is not limited to two.
  • the easy magnetization axis of the magnetic powder particles CPm corresponds to the easy magnetization axis of the crystal of the magnetic material constituting the magnetic powder particles CPm.
  • the arcuate magnet 10 is a ferrite magnet
  • the magnetic powder particles CPm have a hexagonal crystal structure.
  • the easy axis of magnetization of the crystal CRm is the Z axis (see FIG. 3).
  • the bow magnet 10 is heated and exceeds a certain temperature, the crystal of the bow magnet 10 grows abnormally.
  • the abnormally grown crystal reflects light and appears to shine more than the surrounding tissue.
  • the arcuate magnet 10 is a ferrite sintered magnet, for example, as shown in FIG. 3, the direction in which the easy axis (Z axis) of the crystal CRm that appears in the cross section faces is obtained, and the easy axis is at least It can be known whether or not the two axes Zca and Zcb are focused.
  • the arcuate magnet 10 has a portion in which the orientation direction of the magnetic powder particles CPm converges toward the axis Zca and a portion that converges toward the axis Zcb with respect to the center CL in the width direction. And divided.
  • one arcuate magnet 10 is incorporated in a magnetic case 1, and two poles are provided by an inner surface magnetized yoke 2 that is supplied with power from a power source 3 to generate a magnetic field. (N pole, S pole)
  • one of the arcuate magnets 10 defined by the width direction center CL is a first portion 10n, and the other is a second portion 10s.
  • the first portion 10n is magnetized to the N pole and the second portion 10s is magnetized to the S pole.
  • the N pole and the S pole are interchanged in the circumferential direction of one arcuate magnet 10.
  • the direction in which the magnetization easy axes of the plurality of magnetic particle CPm of the arcuate magnet 10 are oriented is toward the axes Zca and Zcb, so the magnetization direction of the arcuate magnet 10 is the axis in the first portion 10n.
  • the magnetic flux of the arcuate magnet 10 is the teeth TS of each electric motor. It becomes easy to concentrate on. As a result, the bow magnet 10 can increase the magnetic flux density that can be used by the teeth TS. This point will be described later.
  • FIG. 6 is a diagram showing the relationship between the bow magnet magnetized one pole at a time and the teeth of the electric motor.
  • FIG. 7 is a diagram showing a relationship between a bow magnet magnetized with two poles and teeth of an electric motor.
  • the respective arcuate magnets 110 n and 110 s are oriented by radial orientation so that the easy axis of magnetization of the magnetic powder particles faces the axes Zca and Zcb, respectively.
  • the arcuate magnet 110n is magnetized to the N pole, and the arcuate magnet 110s is magnetized to the S pole.
  • the arcuate magnet 210 is oriented by radial orientation so that the easy axis of magnetization of the magnetic powder particles faces the axis Zc.
  • the arcuate magnet 210 is subjected to radial orientation, and then the first portion 210n, which is one of the arcuate magnets 210 defined by the center CL in the width direction, is magnetized to the N pole, and the second portion 210s, which is the other.
  • the S pole is magnetized.
  • the magnetic flux from the first portion 210n and the second portion 210s is directed to the axis Zc, so that the amount of magnetic flux passing through each tooth TS of the electric motor Less.
  • the magnetic flux density that can be used by the teeth TS is lower than that of the arcuate magnets 110n and 110s shown in FIG.
  • the direction in which the easy magnetization axes of the magnetic powder particles of the arcuate magnet 10 are oriented is focused toward the axes Zca and Zcb. For this reason, when the arcuate magnet 10 is magnetized, the magnetic flux from the arcuate magnet 10 goes to the axis Zca in the first portion 10n and to the axis Zcb in the second portion 10s.
  • the magnetic flux from the first portion 10n and the magnetic flux from the second portion 10s are directed to the respective teeth TS of the electric motor.
  • the amount of magnetic flux to be generated is larger than that of the arcuate magnet 210.
  • the magnetic flux density that can be used by the teeth TS is larger than that of the arcuate magnet 210 shown in FIG.
  • the arcuate magnets 110n and 110s shown in FIG. 6 are incorporated in the rotor of the electric motor, a constant interval I is generated between them in the circumferential direction.
  • the arcuate magnets 110n and 110s have a constant interval I between the poles in the combination of a pair of N poles and S poles.
  • the arcuate magnet 10 of this embodiment magnetizes one magnet to two poles (N pole, S pole), so that the N pole and S pole are continuous in the circumferential direction. ing. As can be seen from FIGS.
  • the arcuate magnet 10 is different from the case where the N-pole and S-pole arcuate magnets 110 n and 110 s arranged in one pole are arranged in the circumferential direction. There is no fixed interval I between them. For this reason, when the arcuate magnet 10 is used, the teeth TS can also use the magnetic flux of the arcuate magnet 10 from the region (center region) C near the center CL in the width direction. As a result, the magnetic flux density that can be used by the teeth TS is larger than that of the arcuate magnets 110n and 110s shown in FIG. Next, the magnetic flux density (surface magnetic flux density) Bd on the surface of the bow magnet 10 will be described.
  • FIG. 8 and 9 are explanatory diagrams of a method for measuring the surface magnetic flux density of the bow magnet.
  • the Hall element 6 When measuring the surface magnetic flux density Bd, as shown in FIG. 8, the Hall element 6 is arranged in the vicinity of the first curved surface 11 of the magnetized bow-shaped magnet 10. The Hall element 6 at this time is positioned at the center of the first curved surface 11 in the length direction, and is placed in contact with the first curved surface 11 or as close as possible.
  • the distribution of the surface magnetic flux density Bd from one end PA to the other end PB in the circumferential direction of the first curved surface 11 is measured by rotating the arcuate magnet 10 in the circumferential direction (the direction indicated by the arrow CR in FIG. 8). .
  • the arcuate magnet 10 When the arcuate magnet 10 is rotated, the distance between the Hall element 6 and the first curved surface 11 is not changed.
  • the Hall element 6 When measuring the surface magnetic flux density Bd of the second curved surface 12 of the arcuate magnet 10, the Hall element 6 is disposed in the vicinity of the second curved surface 12 of the magnetized arcuate magnet 10, as shown in FIG. The Hall element 6 at this time is positioned at the center of the second curved surface 12 in the length direction, and is placed in contact with the second curved surface 12 or as close as possible. Then, by rotating the arcuate magnet 10 in the circumferential direction (the direction indicated by the arrow CR in FIG. 9), the distribution of the surface magnetic flux density Bd from the one end PC to the other end PD in the circumferential direction of the second curved surface 12 is measured. .
  • FIG. 10 is a diagram showing a waveform of the surface magnetic flux density when the arcuate magnet according to this embodiment is magnetized with one pole.
  • FIG. 11 is a diagram showing a waveform of the surface magnetic flux density when an arcuate magnet having the same size and shape as the arcuate magnet according to the present embodiment is radially oriented and magnetized with one pole.
  • FIG. 12 is a diagram showing a waveform of the surface magnetic flux density in another example when the arcuate magnet according to the present embodiment is magnetized with one pole.
  • the arcuate magnets used in the measurements of FIGS. 10 to 12 are all the same in material, size, and shape, and have different magnetic field orientation methods.
  • the horizontal axis represents the circumferential position ⁇ (degrees) of the arcuate magnet
  • the vertical axis represents the surface magnetic flux density Bd.
  • the circumferential position is a range in the circumferential direction of the first curved surface 11 or the second curved surface 12 of the arcuate magnet 10 in the range where ⁇ is about ⁇ 45 degrees centering on 90 degrees and 270 degrees.
  • the vertical axis in FIG. 10 to FIG. 12 is a relative value obtained by normalizing the measured value with the reference surface magnetic flux density. However, since the reference surface magnetic flux density is the same value, the respective results can be compared.
  • the waveform of Bd has peaks as many as the number of axes (points in the cross section) where the orientation directions (magnet powder particle orientation directions) of the easy magnetization axes of the plurality of magnetic powder particles constituting the arcuate magnet 10 converge.
  • the number of the peaks of the arcuate magnet 10 is twice the number of axes on which the orientation direction converges.
  • the number of the peaks of the arcuate magnet 10 is four.
  • the number of the peaks of the arcuate magnet 10 is two.
  • the waveform of the surface magnetic flux density Bd of the arcuate magnet 10 has two peaks Pi on the first curved surface 11 and two peaks Po on the second curved surface 12.
  • the waveform of the surface magnetic flux density Bd has only one peak.
  • the surface magnetic flux density Bd after magnetization also increases at two different locations in the circumferential direction of the arcuate magnet 10 to form a peak. It is thought that it is to do.
  • the example shown in FIG. 12 is one in which the magnetic field orientation conditions, more specifically, the magnetic field in magnetic field shaping is weaker than the example shown in FIG.
  • the waveform of the surface magnetic flux density Bd of the arcuate magnet 10 has two peaks Po on the second curved surface 12.
  • the waveform of the surface magnetic flux density Bd changes the bending direction of the waveform so that the waveform becomes convex upward at the position indicated by Pvi except for the position where the minimum value is obtained. Since the arcuate magnet 10 has two axes on which the magnetic particle orientation direction of the arcuate magnet 10 converges, the waveform of the surface magnetic flux density Bd is obtained as a result of being concentrated at two different magnetic flux densities in the circumferential direction of the first curved surface 11. Is considered to have changed the direction of bending at the position indicated by Pvi.
  • the waveform of the surface magnetic flux density Bd may differ between the arcuate magnets 10 due to different magnetic field orientation conditions.
  • the waveform of the surface magnetic flux density Bd on at least one of the first curved surface 11 and the second curved surface 12 has a peak as many as the number of axes in which the magnetic particle orientation directions converge.
  • the arcuate magnet 10 has a peak in the waveform (distribution) of the surface magnetic flux density Bd in the circumferential direction of at least one of the first curved surface 11 and the second curved surface 12 by the number of axes on which the magnetic particle orientation direction converges.
  • the maximum value of the surface magnetic flux density Bd is 6 on the first curved surface 11. Degree.
  • the maximum value of the surface magnetic flux density Bd is the value of the peak Pi on the first curved surface 11, which is about 6.8.
  • the minimum value of the surface magnetic flux density Bd of the arcuate magnet 10 is about 6.0 on the first curved surface 11, which is the same as that of the arcuate magnet of FIG.
  • the total flux was compared between the example shown in FIG. 10 and the example shown in FIG.
  • the total flux of the arcuate magnet shown in FIG. 11 that is radially oriented and magnetized with one pole was 172 ⁇ Wb.
  • the total flux of the example shown in FIG. 10, that is, the arcuate magnet 10 in which the magnetic particle orientation directions are focused on two different axes was 177.6 ⁇ Wb. In this way, the total flux of the arcuate magnet 10 is improved by about 3% compared to the arcuate magnet that is radially oriented and magnetized with one pole.
  • the arcuate magnet 10 is higher than the case where the arcuate magnet 10 having the same size and shape is radially oriented by adjusting the magnetic field orientation conditions and adjusting the position of the axis where the magnetic particle orientation direction converges. It can be said that the surface magnetic flux density can be obtained.
  • the surface magnetic flux density Bd on the first curved surface 11 of the arcuate magnet 10 has an absolute value of the peak Pi value of 6.7 and 6.9, and an absolute value of the minimum value of 6.0.
  • the absolute values of the difference between the peak Pi and the minimum value of the waveform of the surface magnetic flux density Bd are 0.7 and 0.9, respectively, and 11.7% and 15% of the absolute value of the minimum value, respectively. It is.
  • the absolute value of the peak Po value is 3.1 in all cases, and the absolute value of the minimum value is 3.5.
  • the absolute value of the difference between the peak Po of the waveform of the surface magnetic flux density Bd and the minimum value is 0.4, which is 11.4% of the absolute value of the minimum value.
  • the surface magnetic flux density Bd on the second curved surface 12 of the arcuate magnet 10 has an absolute value of the peak Po value of 4.2 and 4.1 and an absolute value of the minimum value of 4.45, respectively.
  • the absolute value of the difference between the peak Po and the minimum value of the waveform of the surface magnetic flux density Bd is 0.25 and 0.35, 5.6% and 7.8% of the absolute value of the minimum value. It is.
  • the arcuate magnet 10 has an absolute value of the difference between the peak of the surface magnetic flux density Bd waveform and the minimum value of 5% or more, preferably 10% or more of the absolute value of the minimum value.
  • the magnetic particle orientation direction can be focused on two different axes, and a decrease in magnetic flux density that can be effectively used can be suppressed.
  • the first curved surface 11 of the arcuate magnet 10 faces the teeth 23 included in the stator 26 of the electric motor.
  • the arcuate magnet 10 also has the peak of the waveform of the surface magnetic flux density Bd at two different locations in the circumferential direction even on the second curved surface 12. Therefore, it is preferable to apply the arcuate magnet 10 to an electric motor in which the teeth of the stator and the outer peripheral surface of the arcuate magnet face each other because the teeth can effectively use the magnetic flux density.
  • a magnetic field shaping apparatus for shaping the arcuate magnet 10 will be described.
  • FIG. 13 is an explanatory diagram of a magnetic field shaping apparatus for magnetic field shaping of an arcuate magnet according to the present embodiment.
  • FIG. 14 is an explanatory view showing a molding die included in the magnetic field molding apparatus according to the present embodiment.
  • the arcuate magnet 10 shown in FIGS. 1, 3 and the like is manufactured by being molded (magnetic field molding) in a magnetic field by a magnetic field molding device 50 and sintering this molded body.
  • the magnetic field forming device 50 includes a mold 51, a first punch 52, a second punch 53, and a magnetic field generating coil 55.
  • the magnetic field forming device 50 pressurizes the magnetic powder particles CPm (see FIG.
  • the mold 51, the first punch 52, and the second punch 53 serve as a molding die 50M when the arcuate magnet 10 is magnetically molded.
  • the mold 51 is a ferromagnetic body and has a cylinder part 51C.
  • the cylinder part 51 ⁇ / b> C is a through hole having a rectangular cross section, that is, a shape of the arcuate magnet 10 in a plan view.
  • the first punch 52 is disposed in one opening of the cylinder portion 51C.
  • the second punch 53 enters the cylinder portion 51C from the other opening of the cylinder portion 51C.
  • the first punch 52 is disposed on the opposite side (upward) from the vertical direction, and the second punch 53 is disposed on the vertical direction side (lower).
  • the molding space 54 is a space surrounded by the mold 51, that is, the cylinder portion 51 ⁇ / b> C of the mold 51, the first punch 52, and the second punch 53.
  • magnetic powder particles CPm are introduced into the cylinder portion 51C, and the first punch 52 is disposed in one opening of the cylinder portion 51C. Then, while applying a magnetic field to the magnetic powder particles CPm in the molding space 54 by the magnetic field generating coil 55, the second punch 53 enters the first punch 52 side (in the direction indicated by the arrow P in FIG. 13) to form the molding space.
  • the magnetic powder particles CPm in 54 are pressurized.
  • the magnetic powder particles CPm are pressurized in a magnetic field, so that the easy axis of magnetization of the magnetic powder particles CPm is oriented in the direction of the magnetic field, and the cross section is formed into an arc shape. By sintering the magnetic powder particle compact thus obtained, the bow-shaped magnet 10 can be obtained.
  • the first punch 52 includes a non-magnetic body 52N having a molding surface 52a in contact with the magnetic powder particles CPm, and a ferromagnetic body in contact with the non-magnetic body 52N on the side opposite to the molding surface 52a of the non-magnetic body 52N (molding space 54 side).
  • 52M the nonmagnetic material 52N is in contact with the ferromagnetic material 52M on the side opposite to the molding surface 52a.
  • the second punch 53 is in contact with the nonmagnetic body 53N having a molding surface 53a in contact with the magnetic powder particles CPm, and on the side opposite to the molding surface 53a of the nonmagnetic body 53N (molding space 54 side).
  • a portion in contact with the magnetic body 53N includes a ferromagnetic body 53M having at least two protrusions 56 protruding toward the nonmagnetic body 53N. That is, the nonmagnetic material 53N is in contact with the ferromagnetic material 53M on the side opposite to the molding surface 53a.
  • the nonmagnetic body 52N included in the first punch 52 of the magnetic field forming apparatus 50 and the nonmagnetic body 53N included in the second punch 53 face each other in the cylinder portion 51C of the mold 51.
  • the number of the convex portions 56 corresponds to the number of axes on which the magnetic particle orientation directions of the arcuate magnet 10 shown in FIGS. 1 and 3 are focused, and is not limited to two.
  • the shape of the convex portion 56 is a curved surface shape.
  • the molding surface 52a of the nonmagnetic body 52N of the first punch 52 forms the second curved surface 12 of the arcuate magnet 10.
  • the molding surface 53 a of the nonmagnetic material 53 ⁇ / b> N included in the second punch 53 forms the first curved surface 11 of the arcuate magnet 10. Therefore, the molding surface 52a is a shape obtained by transferring the second curved surface 12 of the arcuate magnet 10, that is, a concave curved surface shape
  • the molding surface 53a is a shape obtained by transferring the first curved surface 11 of the arcuate magnet 10, ie, a convex shape.
  • the curved shape of the shape is a shape obtained by transferring the second curved surface 12 of the arcuate magnet 10, that is, a concave curved surface shape
  • the molding surface 53a is a shape obtained by transferring the first curved surface 11 of the arcuate magnet 10, ie, a convex shape.
  • the ferromagnetic body 53M of the second punch 53 has two curved convex portions 56, so that the magnetic flux in the molding die 50M can be directed to the convex portions 56 and 56, respectively.
  • the easy magnetization axes of the plurality of magnetic particle particles constituting the arcuate magnet 10 are focused toward two different axes Zca and Zcb shown in FIG.
  • the magnetic field shaping device 50 obtains an arcuate magnet 10 in which the magnetic particle orientation directions converge toward two different axes Zca and Zcb existing inside the first curved surface 11 as shown in FIG. be able to.
  • the non-magnetic body 52N of the first punch 52 and the non-magnetic body 53N of the second punch 53 are arranged to face each other in the molding space 54 so as to be in contact with the magnetic powder particles CPm during the magnetic field molding.
  • the orientation of the arcuate magnet 10 can be prevented from converging on the first curved surface 11 or the second curved surface 12.
  • the curvature radius of the curved surface of the convex portion 56, the position of the apex, and the like are appropriately adjusted according to the position of the axis where the magnetic particle orientation direction converges (the same applies hereinafter).
  • the material of the mold 51 and the ferromagnets 52M and 53M made of a ferromagnet is not particularly limited as long as it is generally used.
  • carbon steel, carbon tool steel, alloy tool steel, die steel or the like is used as the material of the mold 51 and the ferromagnetic bodies 52M and 53M.
  • the material of the nonmagnetic materials 52N and 53N is not particularly limited, and Stellite (registered trademark), stainless steel, copper beryllium alloy, high manganese steel, bronze, brass, nonmagnetic super steel, or the like can be used.
  • either one of the first punch 52 and the second punch 53 may have only a ferromagnetic material, and the ferromagnetic material may be in contact with the magnetic powder particles CPm during magnetic field forming. That is, in the present embodiment, at least one of the first punch 52 and the second punch 53 only needs to have a nonmagnetic material. In this way, the magnetic field orientation conditions can be changed without changing the strength of the magnetic field generated by the magnetic field generating coil 55 shown in FIG. For this reason, when at least one of the first punch 52 and the second punch 53 has a non-magnetic material, the degree of freedom in changing the magnetic field orientation condition is increased. As a result, the magnetic field orientation conditions can be easily changed according to the characteristics of the arcuate magnet 10 to be manufactured.
  • the arcuate magnet of the example shown in FIG. 12 is obtained by forming a magnetic field using only the first punch 52 as the ferromagnetic body 52M.
  • the ferromagnetic material in contact with the nonmagnetic material protrudes toward the nonmagnetic material at the portion in contact with the nonmagnetic material.
  • the ferromagnetic material in contact with the nonmagnetic material has at least two convex portions that protrude toward the nonmagnetic material.
  • FIG. 15 is an explanatory view showing a modification of the molding die required for the magnetic field molding apparatus according to this embodiment.
  • the molding die 50Ma is for obtaining an arcuate magnet 10 in which the magnetic particle orientation directions are converged toward two different axes existing outside the second curved surface 12 (see FIG. 2).
  • the ferromagnetic body 52Ma included in the first punch 52a disposed in one opening of the cylinder portion 51C included in the mold 51 has two protrusions 57 projecting toward the nonmagnetic body 52Na. Have one.
  • the second punch 53a includes a nonmagnetic material 53Na and a ferromagnetic material 53Ma in contact with the nonmagnetic material 53N on the molding space 54 side of the nonmagnetic material 53N. Then, the second punch 53a enters the cylinder portion 51C from the other opening.
  • the first punch 52a can direct the magnetic flux in the molding die 50Ma toward the convex portions 57 and 57, respectively.
  • the easy magnetization axes of the plurality of magnetic particle particles constituting the arcuate magnet 10 are focused toward two different axes existing outside the second curved surface 12 (see FIG. 2).
  • the molding die 50Ma can mold the arcuate magnet 10 in which the magnetic particle orientation directions are converged toward two different axes existing outside the second curved surface 12 (see FIG. 2).
  • the second punch 53a may be the second punch 53 shown in FIG. That is, the molding die 50Ma includes at least two nonmagnetic bodies 53N having a molding surface 53a and convex portions 56 that are in contact with the non-molding surface side of the nonmagnetic body 53N and project toward the nonmagnetic body 53N. You may provide the 2nd punch 53 containing the ferromagnetic material 52M which has one. In this way, the easy magnetization axes of the plurality of magnetic powder particles constituting the arcuate magnet 10 are two different axes existing inside the first curved surface 11 and two different axes existing outside the second curved surface 12. It becomes focused toward.
  • the molding die 50Ma having the first punch 52a and the second punch 53 has two different axes existing inside the first curved surface 11 and two different shafts existing outside the second curved surface 12.
  • the arcuate magnet 10 in which the magnetic particle orientation direction is focused toward the axis can be formed.
  • the ferromagnetic material included in at least one of the first punch and the second punch has at least two convex portions protruding toward the nonmagnetic material at the portion in contact with the nonmagnetic material. It only has to have.
  • the arcuate magnet 10 is obtained by joining the partial arcuate magnets 10S and 10S whose dimensions in the circumferential direction of the arcuate magnet 10 shown in FIGS.
  • the partial arcuate magnets 10S and 10S are manufactured.
  • the partial arcuate magnets 10S and 10S are each radially oriented in the magnetic field forming.
  • the magnetic particle orientation directions of the partial arcuate magnets 10S and 10S are focused on the axes Zca and Zcb.
  • the partial arcuate magnets 10S and 10S that have been subjected to the magnetic field shaping are joined to each other at the side surfaces 10SP and 10SP.
  • an epoxy adhesive is used for this bonding.
  • the arcuate magnet 10a is completed.
  • the arcuate magnet 10 converges in the magnetic particle orientation direction toward two different axes Zca and Zcb existing inside the first curved surface 11a.
  • the arcuate magnet 10 can also be manufactured by joining a plurality of radially oriented partial arcuate magnets 10S, 10S. Therefore, according to this method, the arc-shaped magnet 10 can be manufactured without using the molding dies 50M and 50Ma described above.
  • the arcuate magnet according to the present embodiment in the cross section cut by the plane orthogonal to the length direction, the plurality of magnetic particle particles included in the arcuate magnet are focused on at least two points in the orientation direction of the easy magnetization axis.
  • the number of poles is the same as the number of points to be focused (2 in this embodiment).
  • the arcuate magnet according to the present embodiment is an arcuate magnet having a size in which two arcuate magnets are connected in the circumferential direction when arcuate magnets magnetized to one pole are alternately arranged with N and S poles.
  • One bow magnet is used with two poles.
  • the arcuate magnet according to the present embodiment is used for an electric motor, the arcuate magnet is assembled to the electric motor as compared with the case where the arcuate magnets magnetized to one pole are alternately arranged with N and S poles. Since the work can be reduced, the productivity of the electric motor can be improved and the manufacturing cost can be reduced.
  • the number of bow magnets to be used is smaller than that in the case where arc magnets magnetized on one pole are alternately arranged with N poles and S poles. Can be halved.
  • the time required for magnetic field shaping is almost the same even if the dimensions of the arcuate magnet change. For this reason, the fact that the number of arcuate magnets used in one electric motor can be halved means that the time for manufacturing all the arcuate magnets used in one electric motor can be halved.
  • the arcuate magnet is a ferrite sintered magnet
  • polishing is necessary after sintering in order to obtain the necessary shape and dimensions.
  • the arcuate magnet is usually sent to the polishing apparatus along its length. That is, in polishing, the total length of the arcuate magnet that passes through the polishing apparatus is proportional to the time required for polishing.
  • the fact that the number of arcuate magnets used in an electric motor can be halved means that the number of all arcuate magnets used in a single electric motor can be halved.
  • the arcuate magnet according to the present embodiment halves the total length of the arcuate magnet passing through the polishing apparatus as compared with the case where the arcuate magnets magnetized to one pole are alternately arranged with N poles and S poles. As a result, the time required for polishing can be halved.
  • the completed bow magnets are inspected, and those that pass the inspection are packed and shipped as products.
  • the fact that the number of arcuate magnets used in a single electric motor can be halved means that the number of arcuate magnets to be inspected can be halved. For this reason, since the time required for the inspection is reduced by half, the productivity of the bow magnet is improved and the burden on the inspector is reduced.
  • one electric motor can be used as compared with the case where arcuate magnets magnetized in one pole are alternately arranged in N and S poles. It is also possible to reduce the amount of packing material for packing the minute bow-shaped magnet.
  • the arcuate magnet according to the present embodiment can reduce the environmental load.
  • the bow magnet according to the present embodiment improves the productivity and reduces the manufacturing cost as compared with the case where the arc magnet magnetized to one pole is alternately arranged with the N pole and the S pole. There is an advantage that the burden on the inspector and the environmental load can be reduced.

Abstract

An arched magnet (10) is a magnet containing a plurality of magnetic powder particles and having an arc-shaped cross section. In the arched magnet (10), in a cross section cut along a plane orthogonal to the lengthwise direction thereof, the orientation directions of magnetization easy axes of the plurality of magnetic powder particles are orientated so as to converge to two points, that is, points at which two different axes (Zca, Zcb) intersect the cross section. In doing so, magnetic fluxes from the arched magnet (10) go to the two different axes (Zca, Zcb). As a result, the arched magnet (10) achieves an increase in effectively utilizable magnetic flux density.

Description

弓形磁石及び磁場成形用金型Bow magnets and magnetic field molds
　本発明は、円弧形状をした弓形磁石及び磁場成形用金型に関する。 The present invention relates to an arc-shaped arcuate magnet and a magnetic field molding die.
　弓形磁石は、円弧状の形状をしており、電動機のロータ又はステータ等に用いられる。例えば、特許文献１には、円弧状で径方向に異方性を有するフェライト磁石を製造する際に、配向用強磁性体を設けた乾式成形装置を用いることにより、異方性方向が径方向に揃った成形体を得ることが記載されている。また、特許文献１には、異方性フェライト磁石の表面磁束密度を規定することにより、モータのコギングトルク及びトルクリップルを低減することも記載されている。 The arcuate magnet has an arc shape and is used for a rotor or a stator of an electric motor. For example, in Patent Document 1, when manufacturing a ferritic magnet having an arc shape and anisotropy in the radial direction, by using a dry molding apparatus provided with an orientation ferromagnetic material, the anisotropy direction is in the radial direction. Is obtained. Patent Document 1 also describes that the cogging torque and torque ripple of the motor are reduced by defining the surface magnetic flux density of the anisotropic ferrite magnet.
特開２００７－２８１４３７号公報JP 2007-281437 A
　電動機に弓形磁石を用いる場合、例えば、１極に着磁した弓形磁石を、ロータ又はステータの周方向に向かってＮ極、Ｓ極と交互に配置する。近年においては、電動機に用いる弓形磁石の個数を低減する要請がある。この場合、例えば、周方向における寸法が１極に着磁した弓形磁石よりも大きい弓形磁石を、２極に着磁して用いることがある。このようにして、１台の電動機に用いる弓形磁石の個数を低減することができるが、この場合、異方性方向を径方向に揃え、かつ２極に着磁しただけでは、１極に着磁した弓形磁石を用いる場合と比較して、有効に利用できる磁束密度が低減するという問題があった。特許文献１にこの点については開示も示唆もなく、改善の余地がある。本発明は、複数の極に着磁された弓形磁石において、有効に利用できる磁束密度の低下を抑制することを目的とする。 When an arcuate magnet is used for an electric motor, for example, arcuate magnets magnetized on one pole are alternately arranged with N and S poles in the circumferential direction of the rotor or stator. In recent years, there has been a demand to reduce the number of arcuate magnets used in electric motors. In this case, for example, an arcuate magnet whose dimension in the circumferential direction is larger than an arcuate magnet magnetized to one pole may be used by magnetizing to two poles. In this way, the number of arcuate magnets used in one electric motor can be reduced. In this case, if the anisotropic direction is aligned in the radial direction and only two poles are magnetized, one arcuate magnet is attached. Compared with the case of using a magnetized arcuate magnet, there is a problem that the magnetic flux density that can be effectively used is reduced. Patent Document 1 does not disclose or suggest this point, and there is room for improvement. An object of the present invention is to suppress a decrease in magnetic flux density that can be effectively used in an arcuate magnet magnetized on a plurality of poles.
　上述した課題を解決するため、本発明に係る焼結磁石は、複数の磁粉粒子を含む磁石であり、当該磁石の長さ方向と直交する面で切った横断面において、前記複数の磁粉粒子は、磁化容易軸の配向方向が、少なくとも２つの点に集束するように配向されていることを特徴とする。 In order to solve the above-described problem, a sintered magnet according to the present invention is a magnet including a plurality of magnetic powder particles, and in the cross section cut by a plane orthogonal to the length direction of the magnet, the plurality of magnetic powder particles are The orientation direction of the easy axis of magnetization is oriented so as to focus on at least two points.
　この弓形磁石は、長さ方向と直交する面で切った横断面が円弧形状であり、かつ前記横断面において、複数の磁粉粒子の磁化容易軸の配向方向は、少なくとも２つの点に集束するようになっており、かつ、集束する点の数と同じ極の数に着磁される。このようにすることで、この弓形磁石から、これに対向する電動機のティースへ向けて磁束を集中させることができる。その結果、この弓形磁石は、複数の極に着磁された弓形磁石において、有効に利用できる磁束密度の低下を抑制できるとともに、１極に着磁した弓形磁石をＮ極、Ｓ極と交互に配列した場合と比較して、ティースが利用できる磁束密度を同等以上とすることができる。 The arcuate magnet has a circular cross section cut by a plane orthogonal to the length direction, and the orientation direction of the easy axis of the plurality of magnetic particle particles is converged to at least two points in the cross section. And is magnetized to the same number of poles as the number of converging points. By doing in this way, magnetic flux can be concentrated from this arcuate magnet toward the teeth of the electric motor facing this. As a result, this arcuate magnet can suppress a decrease in magnetic flux density that can be effectively used in an arcuate magnet magnetized on a plurality of poles, and an arcuate magnet magnetized on one pole alternately with N and S poles. Compared with the case where it arranges, the magnetic flux density which a tooth can utilize can be made equivalent or more.
　本発明の望ましい態様として、弓形磁石を１極で着磁した場合において、当該弓形磁石の前記横断面における形状が円弧形状の第１曲面と、当該第１曲面の外側に対向して配置されるとともに前記横断面における形状が円弧形状の第２曲面との少なくとも一方での磁束密度の波形は、前記配向方向が集束する点の数だけピークを有することが好ましい。このようにすることで、複数の磁粉粒子の磁化容易軸の配向方向が、少なくとも２つの点に集束するので、複数の極に着磁された弓形磁石において、有効に利用できる磁束密度の低下を抑制できる。 As a desirable mode of the present invention, when the arcuate magnet is magnetized with one pole, the arcuate magnet is arranged so that the cross-sectional shape of the arcuate magnet is an arc-shaped first curved surface and the outside of the first curved surface. In addition, it is preferable that the waveform of the magnetic flux density on at least one of the second curved surface having a circular arc shape in the cross section has a peak as many as the number of points where the orientation directions converge. By doing so, the orientation directions of the easy magnetization axes of the plurality of magnetic powder particles are focused on at least two points, so that the magnetic flux density that can be effectively used is reduced in the arcuate magnets magnetized on the plurality of poles. Can be suppressed.
　本発明の望ましい態様として、前記波形の前記ピークと最小値との差の絶対値は、前記最小値の絶対値の５％以上であることが好ましい。このようにすることで、複数の磁粉粒子の磁化容易軸の配向方向は、少なくとも２つの点に集束するようになるので、複数の極に着磁された弓形磁石において、有効に利用できる磁束密度の低下を抑制できる。 As a desirable mode of the present invention, the absolute value of the difference between the peak and the minimum value of the waveform is preferably 5% or more of the absolute value of the minimum value. By doing so, the orientation directions of the easy magnetization axes of the plurality of magnetic powder particles are focused on at least two points. Therefore, the magnetic flux density that can be effectively used in the arcuate magnet magnetized on the plurality of poles. Can be suppressed.
　上述した課題を解決するため、本発明に係る磁場成形用金型は、型枠と、第１パンチと、第２パンチとを含み、前記型枠と前記第１パンチと前記第２パンチとで囲まれる成形空間内の磁粉粒子を加圧して、円弧状の形状に成形する磁場成形用金型であり、前記第１パンチと前記第２パンチとの少なくとも一方は、前記磁粉粒子と接する成形面を有する非磁性体と、前記非磁性体の前記成形面とは反対側で前記非磁性体と接し、かつ前記非磁性体と接する部分に、前記非磁性体に向かって突出する凸部を少なくとも２つ有する強磁性体と、を有することを特徴とする。 In order to solve the above-described problem, a magnetic field molding die according to the present invention includes a mold frame, a first punch, and a second punch, and includes the mold frame, the first punch, and the second punch. A magnetic field molding die for pressurizing magnetic powder particles in an enclosed molding space to form an arc shape, wherein at least one of the first punch and the second punch is in contact with the magnetic powder particles A non-magnetic body having a convex portion projecting toward the non-magnetic body at a portion that is in contact with the non-magnetic body on the side opposite to the molding surface of the non-magnetic body and is in contact with the non-magnetic body. And having two ferromagnets.
　例えば、前記第１パンチ及び前記第２パンチの両方が前記非磁性体を有する場合、前記強磁性体のうち少なくとも一つは、前記非磁性体と接する部分に前記非磁性体に向かって突出する凸部を少なくとも２つ有する。また、前記第１パンチ又は前記第２パンチのいずれか一方が前記非磁性体を有する場合、前記非磁性体と接する強磁性体は、前記非磁性体と接する部分に、前記非磁性体に向かって突出する凸部を少なくとも２つ有する。この成形用金型を用いて磁粉粒子を磁場成形することにより、長さ方向と直交する面で切った横断面において、複数の磁粉粒子の磁化容易軸の配向方向が、少なくとも２つの点に集束した弓形磁石を得ることができる。 For example, when both the first punch and the second punch have the nonmagnetic material, at least one of the ferromagnetic materials protrudes toward the nonmagnetic material at a portion in contact with the nonmagnetic material. It has at least two convex parts. Further, when either the first punch or the second punch has the nonmagnetic material, the ferromagnetic material in contact with the nonmagnetic material is directed to the nonmagnetic material at a portion in contact with the nonmagnetic material. And at least two convex portions projecting. By magnetically forming the magnetic powder particles using this molding die, the orientation directions of the easy magnetization axes of the magnetic powder particles are converged to at least two points in a cross section cut by a plane orthogonal to the length direction. An arcuate magnet can be obtained.
　本発明は、複数の極に着磁された弓形磁石において、有効に利用できる磁束密度の低下を抑制することができる。 The present invention can suppress a decrease in magnetic flux density that can be effectively used in an arcuate magnet magnetized on a plurality of poles.
図１は、本実施形態に係る弓形磁石の一例を示す斜視図である。FIG. 1 is a perspective view showing an example of an arcuate magnet according to the present embodiment. 図２は、本実施形態に係る弓形磁石の長さ方向と直交する面で切った状態を示す断面図である。FIG. 2 is a cross-sectional view showing a state in which the bow-shaped magnet according to this embodiment is cut by a plane orthogonal to the length direction. 図３は、本実施形態に係る弓形磁石の横断面において、磁粉粒子の磁化容易軸の配向方向を示す断面図である。FIG. 3 is a cross-sectional view showing the orientation direction of the easy axis of magnetic powder particles in the cross section of the bow magnet according to the present embodiment. 図４は、着磁を説明するための図である。FIG. 4 is a diagram for explaining magnetization. 図５は、本実施形態に係る弓形磁石を着磁した状態を示す模式図である。FIG. 5 is a schematic diagram showing a state in which the bow magnet according to the present embodiment is magnetized. 図６は、１極ずつ着磁した弓形磁石と電動機のティースとの関係を示す図である。FIG. 6 is a diagram showing the relationship between the arcuate magnet magnetized one pole at a time and the teeth of the electric motor. 図７は、２極の着磁をした弓形磁石と電動機のティースとの関係を示す図である。FIG. 7 is a diagram showing a relationship between a bow magnet magnetized with two poles and teeth of an electric motor. 図８は、弓形磁石の表面磁束密度を測定する手法の説明図である。FIG. 8 is an explanatory diagram of a method for measuring the surface magnetic flux density of an arcuate magnet. 図９は、弓形磁石の表面磁束密度を測定する手法の説明図である。FIG. 9 is an explanatory diagram of a method for measuring the surface magnetic flux density of an arcuate magnet. 図１０は、本実施形態に係る弓形磁石を１極で着磁した場合における表面磁束密度の波形を示す図である。FIG. 10 is a diagram showing a waveform of the surface magnetic flux density when the arcuate magnet according to the present embodiment is magnetized with one pole. 図１１は、本実施形態に係る弓形磁石と寸法及び形状が同じ弓形磁石をラジアル配向して１極で着磁した場合における表面磁束密度の波形を示す図である。FIG. 11 is a diagram showing a waveform of the surface magnetic flux density when an arcuate magnet having the same size and shape as the arcuate magnet according to the present embodiment is radially oriented and magnetized with one pole. 図１２は、本実施形態に係る弓形磁石を１極で着磁した場合の他の例における表面磁束密度の波形を示す図である。FIG. 12 is a diagram showing a waveform of the surface magnetic flux density in another example when the arcuate magnet according to the present embodiment is magnetized with one pole. 図１３は、本実施形態に係る弓形磁石を磁場成形する磁場成形装置の説明図である。FIG. 13 is an explanatory diagram of a magnetic field shaping apparatus for shaping a bow magnet according to the present embodiment. 図１４は、本実施形態に係る磁場成形装置が有する成形用金型を示す説明図である。FIG. 14 is an explanatory view showing a molding die included in the magnetic field molding apparatus according to the present embodiment. 図１５は、本実施形態に係る磁場成形装置が有する成形要金型の変形例を示す説明図である。FIG. 15 is an explanatory view showing a modification of the molding die required for the magnetic field molding apparatus according to the present embodiment. 図１６は、本実施形態に係る弓形磁石を製造する他の手法を示す説明図である。FIG. 16 is an explanatory view showing another method for manufacturing the bow magnet according to the present embodiment. 図１７は、本実施形態に係る弓形磁石を製造する他の手法を示す説明図である。FIG. 17 is an explanatory view showing another method for manufacturing the bow magnet according to the present embodiment.
　以下、本発明につき図面を参照しつつ詳細に説明する。なお、以下の説明により本発明が限定されるものではない。以下の説明における構成要素には、当業者が容易に想定できるもの、実質的に同一のもの、いわゆる均等の範囲のものが含まれる。また、以下に開示する構成は、適宜組み合わせることが可能である。 Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following description. The constituent elements in the following description include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. The configurations disclosed below can be combined as appropriate.
　図１は、本実施形態に係る弓形磁石の一例を示す斜視図である。図２は、本実施形態に係る弓形磁石の長さ方向と直交する面で切った状態を示す断面図である。弓形磁石１０は、全体がアーチ形状である。そして、弓形磁石１０は、第１曲面１１と、第１曲面１１の外側１１ｏに、第１曲面１１と対向して配置される第２曲面１２と、第１曲面１１と第２曲面１２とにつながる側面１３と、を有する形状である。本実施形態において、弓形磁石１０は、複数、より具体的には４個の側面１３Ａ、１３Ｂ、１３Ｃ、１３Ｄを有する。それぞれの側面１３Ａ、１３Ｂ、１３Ｃ、１３Ｄは平面であり、互いに直交している。なお、本実施形態において側面１３は４個であるが、側面の数はこれに限定されるものではない。例えば、側面１３Ｂ、１３Ｄと第１曲面１１との境界を面取りし、側面１３を６個にしてもよいし、側面１３Ｂ、１３Ｄと第２曲面１２との境界を面取りし、側面１３を６個にしてもよい。 FIG. 1 is a perspective view showing an example of an arcuate magnet according to the present embodiment. FIG. 2 is a cross-sectional view showing a state in which the bow-shaped magnet according to this embodiment is cut by a plane orthogonal to the length direction. The arcuate magnet 10 has an arch shape as a whole. The arcuate magnet 10 is divided into a first curved surface 11, a second curved surface 12 disposed on the outer side 11 o of the first curved surface 11, opposite to the first curved surface 11, and the first curved surface 11 and the second curved surface 12. And a side surface 13 to be connected. In the present embodiment, the arcuate magnet 10 has a plurality of, more specifically, four side surfaces 13A, 13B, 13C, and 13D. Each of the side surfaces 13A, 13B, 13C, and 13D is a plane and is orthogonal to each other. In the present embodiment, there are four side surfaces 13, but the number of side surfaces is not limited to this. For example, the boundary between the side surfaces 13B and 13D and the first curved surface 11 may be chamfered to provide six side surfaces 13, or the boundary between the side surfaces 13B and 13D and the second curved surface 12 may be chamfered to provide six side surfaces 13. It may be.
　第１曲面１１又は第２曲面１２は、それぞれ所定の軸Ｚａ、Ｚｂを中心とした円筒の一部である。第１曲面１１及び第２曲面の形状は、軸Ｚａ、Ｚｂと直交する平面で切った場合に、円弧形状、すなわち円の一部の形状となる。本実施形態においては、軸Ｚａ、Ｚｂは同一であり、第１曲面１１の曲率半径ｒａと第２曲面１２の曲率半径ｒｂの大きさが異なる（ｒａ＜ｒｂ）。なお、軸Ｚａ、Ｚｂは異なっていてもよい。また、第１曲面１１及び第２曲面１２は、それぞれ曲率半径が異なっていても同一であってもよい。 The first curved surface 11 or the second curved surface 12 is a part of a cylinder centering on predetermined axes Za and Zb, respectively. The shape of the first curved surface 11 and the second curved surface is an arc shape, that is, a shape of a part of a circle when cut by a plane orthogonal to the axes Za and Zb. In the present embodiment, the axes Za and Zb are the same, and the curvature radius ra of the first curved surface 11 and the curvature radius rb of the second curved surface 12 are different (ra <rb). The axes Za and Zb may be different. Further, the first curved surface 11 and the second curved surface 12 may have the same or different curvature radii.
　弓形磁石１０の長さ方向とは、第１曲面１１又は第２曲面１２の中心となる軸Ｚａ又は軸Ｚｂと平行な方向である。これは、第１曲面１１の曲面又は第２曲面１２の曲面、すなわちＲに沿った方向（図１の矢印Ｃで示す方向）と直交し、かつ第１曲面１１の曲面又は第２曲面１２の曲面と平行な方向である。本実施形態において、前記長さ方向は、平面形状が長方形の側面１３Ｂ、１３Ｄと、第１曲面１１又は第２曲面１２との境界線ＢＬと平行な方向であるともいえる。前記長さ方向と直交する平面で弓形磁石１０を切った断面を、弓形磁石１０の横断面という。第１曲面１１及び第２曲面１２の横断面における形状は、円弧形状である。また、前記長さ方向と直交する方向を幅方向といい、図２に示す軸Ｚａ又は軸Ｚｂを中心とし、かつ弓形磁石１０を通る円の周方向を、弓形磁石１０の周方向という。前記長さ方向における弓形磁石１０の寸法を弓形磁石１０の長さ（符号はＬ）、幅方向における弓形磁石１０の最大寸法を弓形磁石１０の幅（符号はＷ）という。 The length direction of the arcuate magnet 10 is a direction parallel to the axis Za or the axis Zb that is the center of the first curved surface 11 or the second curved surface 12. This is orthogonal to the curved surface of the first curved surface 11 or the curved surface of the second curved surface 12, that is, the direction along R (the direction indicated by the arrow C in FIG. 1), and the curved surface of the first curved surface 11 or the second curved surface 12. The direction is parallel to the curved surface. In the present embodiment, the length direction can be said to be a direction parallel to a boundary line BL between the side surfaces 13B and 13D having a rectangular planar shape and the first curved surface 11 or the second curved surface 12. A cross section obtained by cutting the arcuate magnet 10 along a plane perpendicular to the length direction is referred to as a transverse cross section of the arcuate magnet 10. The shape in the cross section of the 1st curved surface 11 and the 2nd curved surface 12 is circular arc shape. A direction perpendicular to the length direction is referred to as a width direction, and a circumferential direction of a circle centering on the axis Za or the axis Zb shown in FIG. 2 and passing through the arcuate magnet 10 is referred to as a circumferential direction of the arcuate magnet 10. The dimension of the arcuate magnet 10 in the length direction is referred to as the length of the arcuate magnet 10 (reference numeral L), and the maximum dimension of the arcuate magnet 10 in the width direction is referred to as the width of the arcuate magnet 10 (reference numeral W).
　弓形磁石１０は、全体はアーチ形状で、横断面の形状が円弧形状又はＣ形形状又は扇形形状である。弓形磁石１０は、セグメント形の磁石（セグメント磁石）とも呼ばれ、例えば、電動機のステータ（固定子）又はロータ（回転子）等に用いられる。弓形磁石１０の適用対象は、電動機に限定されるものではない。例えば、弓形磁石１０は、スピーカ、マイク、マグネトロン管、ＭＲＩ用磁場発生装置、ＡＢＳセンサ、燃料・オイルレベルセンサ、ディストリビュータ用センサ、マグネットクラッチ等に用いる永久磁石に対しても広く適用できる。 The arcuate magnet 10 as a whole has an arch shape, and the cross-sectional shape is an arc shape, a C shape, or a fan shape. The arcuate magnet 10 is also called a segment-type magnet (segment magnet), and is used, for example, for a stator (stator) or a rotor (rotor) of an electric motor. The application target of the bow magnet 10 is not limited to the electric motor. For example, the bow magnet 10 can be widely applied to permanent magnets used in speakers, microphones, magnetron tubes, magnetic field generators for MRI, ABS sensors, fuel / oil level sensors, distributor sensors, magnet clutches, and the like.
　本実施形態において、弓形磁石１０はフェライト焼結磁石である。フェライト焼結磁石は、複数のフェライトの磁粉粒子を焼結して得られる。フェライト焼結磁石は、比較的高い磁気特性を有しつつ、安価であることから広く使用されている。フェライト焼結磁石の種類は特に限定されるものではなく、バリウム系、ストロンチウム系、カルシウム系等、いずれでもよい。弓形磁石１０がフェライト焼結磁石である場合、弓形磁石１０の製法は、湿式製法、乾式製法いずれであってもよく、製法は問わない。 In this embodiment, the arcuate magnet 10 is a ferrite sintered magnet. The sintered ferrite magnet is obtained by sintering a plurality of ferrite magnetic particles. Ferrite sintered magnets are widely used because they have relatively high magnetic properties and are inexpensive. The kind of sintered ferrite magnet is not particularly limited, and may be any of barium-based, strontium-based, calcium-based and the like. When the arcuate magnet 10 is a ferrite sintered magnet, the manufacturing method of the arcuate magnet 10 may be either a wet manufacturing method or a dry manufacturing method, and the manufacturing method is not limited.
　なお、本実施形態において、弓形磁石１０の種類はフェライト焼結磁石に限定されるものではなく、希土類焼結磁石やサマリウム・コバルト系焼結磁石のような金属焼結磁石であってもよい。また、弓形磁石１０は、磁粉粒子を樹脂又はゴム等で固めたボンド磁石であってもよい。すなわち、本実施形態に係る弓形磁石１０は、複数の磁粉粒子を成形して得られる、複数の磁粉粒子を含む磁石全般が対象となる。 In the present embodiment, the type of the arcuate magnet 10 is not limited to a ferrite sintered magnet, and may be a sintered metal magnet such as a rare earth sintered magnet or a samarium / cobalt sintered magnet. The arcuate magnet 10 may be a bonded magnet in which magnetic powder particles are hardened with resin or rubber. In other words, the arcuate magnet 10 according to the present embodiment is intended for all magnets including a plurality of magnetic powder particles obtained by molding a plurality of magnetic powder particles.
　図３は、本実施形態に係る弓形磁石の横断面において、磁粉粒子の磁化容易軸の配向方向を示す断面図である。図３に示す矢印が磁粉粒子ＣＰｍの配向方向を示し、ＣＬは、弓形磁石１０の幅方向中心を示す（以下同様）。図４は、着磁を説明するための図である。図５は、本実施形態に係る弓形磁石を着磁した状態を示す模式図である。本実施形態において、弓形磁石１０は、複数の磁粉粒子ＣＰｍの磁化容易軸が、少なくとも２つの軸Ｚｃａ、Ｚｃｂに向かって集束するように配向している。すなわち、弓形磁石１０は、図３に示すように、その横断面において、複数の磁粉粒子ＣＰｍは、磁化容易軸の配向方向が、少なくとも２つの点（２つの軸Ｚｃａ、Ｚｃｂと前記横断面との交点）に集束するように配向されている。磁粉粒子を固めて弓形磁石１０の形状とする際に、磁場中で成形しながら配向（磁場成形）させることにより、磁化容易軸が少なくとも２つの軸Ｚｃａ、Ｚｃｂに向かって集束するように磁粉粒子ＣＰｍを配向させる。この磁場成形の手法は後述する。なお、本実施形態において、磁粉粒子の磁化容易軸の配向方向が集束する部分は、２に限定されるものではない。 FIG. 3 is a cross-sectional view showing the orientation direction of the easy axis of magnetization of the magnetic particle in the cross section of the bow magnet according to the present embodiment. 3 indicates the orientation direction of the magnetic powder particles CPm, and CL indicates the center of the arcuate magnet 10 in the width direction (the same applies hereinafter). FIG. 4 is a diagram for explaining magnetization. FIG. 5 is a schematic diagram showing a state in which the bow magnet according to the present embodiment is magnetized. In the present embodiment, the arcuate magnet 10 is oriented so that the easy axes of the plurality of magnetic powder particles CPm converge toward at least two axes Zca and Zcb. That is, as shown in FIG. 3, the arcuate magnet 10 has a plurality of magnetic powder particles CPm in which the orientation direction of the easy magnetization axis is at least two points (two axes Zca and Zcb and the cross section) as shown in FIG. Is oriented to converge at the intersection of When the magnetic powder particles are hardened into the shape of the arched magnet 10, the magnetic powder particles are oriented so that the easy axis of magnetization is focused toward at least two axes Zca and Zcb by forming the magnetic powder particles while being molded in a magnetic field (magnetic field shaping). Orient the CPm. This magnetic field shaping method will be described later. In the present embodiment, the portion where the orientation direction of the easy magnetization axis of the magnetic powder particles converges is not limited to two.
　磁粉粒子ＣＰｍの磁化容易軸は、磁粉粒子ＣＰｍを構成する磁性材料の結晶の磁化容易軸に相当する。弓形磁石１０がフェライト磁石である場合、磁粉粒子ＣＰｍは六方晶型の結晶構造を有する。このような結晶構造である場合、結晶ＣＲｍの磁化容易軸は、Ｚ軸である（図３参照）。弓形磁石１０を加熱し、ある温度を超えると弓形磁石１０の結晶は異常成長を起こす。このような弓形磁石１０の横断面を研磨すると、異常成長した結晶は光を反射するようになり、周囲の組織よりも光って見える。したがって、弓形磁石１０の結晶を異常成長させて横断面に現れた結晶を観察することにより、磁粉粒子ＣＰｍの磁化容易軸が少なくとも２つの軸Ｚｃａ、Ｚｃｂに向かって集束しているか否かを観察することができる。弓形磁石１０がフェライト焼結磁石である場合、例えば、図３に示すように、横断面に現れた結晶ＣＲｍの磁化容易軸（Ｚ軸）が向いている方向を求めて、磁化容易軸が少なくとも２つの軸Ｚｃａ、Ｚｃｂに向かって集束しているか否かを知ることができる。 The easy magnetization axis of the magnetic powder particles CPm corresponds to the easy magnetization axis of the crystal of the magnetic material constituting the magnetic powder particles CPm. When the arcuate magnet 10 is a ferrite magnet, the magnetic powder particles CPm have a hexagonal crystal structure. In such a crystal structure, the easy axis of magnetization of the crystal CRm is the Z axis (see FIG. 3). When the bow magnet 10 is heated and exceeds a certain temperature, the crystal of the bow magnet 10 grows abnormally. When such a cross section of the arcuate magnet 10 is polished, the abnormally grown crystal reflects light and appears to shine more than the surrounding tissue. Therefore, by observing the crystal appearing in the cross section by abnormally growing the crystal of the arcuate magnet 10, it is observed whether or not the easy magnetization axes of the magnetic powder particles CPm are focused toward at least two axes Zca and Zcb. can do. When the arcuate magnet 10 is a ferrite sintered magnet, for example, as shown in FIG. 3, the direction in which the easy axis (Z axis) of the crystal CRm that appears in the cross section faces is obtained, and the easy axis is at least It can be known whether or not the two axes Zca and Zcb are focused.
　磁粉粒子ＣＰｍを上述したように配向させることにより、弓形磁石１０は、幅方向中心ＣＬを境に磁粉粒子ＣＰｍの配向方向が軸Ｚｃａに向かって集束する部分と、軸Ｚｃｂに向かって集束する部分とに分けられる。本実施形態において、例えば、図４に示すように、１個の弓形磁石１０は、磁性のケース１に組み込まれ、電源３から電力が供給されて磁界を発生させる内面着磁ヨーク２により２極（Ｎ極、Ｓ極）に着磁される。 By orienting the magnetic powder particles CPm as described above, the arcuate magnet 10 has a portion in which the orientation direction of the magnetic powder particles CPm converges toward the axis Zca and a portion that converges toward the axis Zcb with respect to the center CL in the width direction. And divided. In the present embodiment, for example, as shown in FIG. 4, one arcuate magnet 10 is incorporated in a magnetic case 1, and two poles are provided by an inner surface magnetized yoke 2 that is supplied with power from a power source 3 to generate a magnetic field. (N pole, S pole)
　例えば、図５に示すように、幅方向中心ＣＬで区画される弓形磁石１０の一方を第１部分１０ｎとし、他方を第２部分１０ｓとする。図５に示す例では、第１部分１０ｎがＮ極に、第２部分１０ｓがＳ極に着磁される。このため、１個の弓形磁石１０は、その周方向に向かってＮ極とＳ極とが入れ替わる。上述したように、弓形磁石１０が有する複数の磁粉粒子ＣＰｍの磁化容易軸が配向する方向は、軸Ｚｃａ、Ｚｃｂに向かっているので、弓形磁石１０の磁化の方向は、第１部分１０ｎにおいて軸Ｚｃａに向かい、第２部分１０ｓにおいて軸Ｚｃｂに向かう。このように、弓形磁石１０は、第１部分１０ｎと第２部分１０ｓとでそれぞれ磁化の方向が異なるため、弓形磁石１０を電動機に用いた場合、弓形磁石１０の磁束はそれぞれの電動機のティースＴＳに集中しやすくなる。その結果、弓形磁石１０は、ティースＴＳが利用できる磁束密度を増加させることができる。この点については後述する。 For example, as shown in FIG. 5, one of the arcuate magnets 10 defined by the width direction center CL is a first portion 10n, and the other is a second portion 10s. In the example shown in FIG. 5, the first portion 10n is magnetized to the N pole and the second portion 10s is magnetized to the S pole. For this reason, the N pole and the S pole are interchanged in the circumferential direction of one arcuate magnet 10. As described above, the direction in which the magnetization easy axes of the plurality of magnetic particle CPm of the arcuate magnet 10 are oriented is toward the axes Zca and Zcb, so the magnetization direction of the arcuate magnet 10 is the axis in the first portion 10n. It goes to Zca and goes to the axis Zcb in the second portion 10s. Thus, since the direction of magnetization of the arcuate magnet 10 is different between the first part 10n and the second part 10s, when the arcuate magnet 10 is used in an electric motor, the magnetic flux of the arcuate magnet 10 is the teeth TS of each electric motor. It becomes easy to concentrate on. As a result, the bow magnet 10 can increase the magnetic flux density that can be used by the teeth TS. This point will be described later.
　図６は、１極ずつ着磁した弓形磁石と電動機のティースとの関係を示す図である。図７は、２極の着磁をした弓形磁石と電動機のティースとの関係を示す図である。図６に示す例において、それぞれの弓形磁石１１０ｎ、１１０ｓは、ラジアル配向により、磁粉粒子の磁化容易軸がそれぞれ軸Ｚｃａ、Ｚｃｂへ向くように配向される。そして、弓形磁石１１０ｎはＮ極に、弓形磁石１１０ｓはＳ極に着磁される。このような弓形磁石１１０ｎ、１１０ｓを、電動機のロータに組み付けると、それぞれの弓形磁石１１０ｎ、１１０ｓからの磁束は、それぞれ軸Ｚｃａ、Ｚｃｂへ向かう。その結果、前記磁束は、電動機のそれぞれのティースＴＳに集中しやすくなるとともに、それぞれのティースＴＳを通過する磁束量も多くなる。 FIG. 6 is a diagram showing the relationship between the bow magnet magnetized one pole at a time and the teeth of the electric motor. FIG. 7 is a diagram showing a relationship between a bow magnet magnetized with two poles and teeth of an electric motor. In the example shown in FIG. 6, the respective arcuate magnets 110 n and 110 s are oriented by radial orientation so that the easy axis of magnetization of the magnetic powder particles faces the axes Zca and Zcb, respectively. The arcuate magnet 110n is magnetized to the N pole, and the arcuate magnet 110s is magnetized to the S pole. When such arcuate magnets 110n and 110s are assembled to the rotor of the electric motor, the magnetic fluxes from the arcuate magnets 110n and 110s are directed to the axes Zca and Zcb, respectively. As a result, the magnetic flux easily concentrates on each tooth TS of the electric motor, and the amount of magnetic flux passing through each tooth TS increases.
　図７に示す例の弓形磁石２１０は、周方向の寸法が、図６に示す弓形磁石１１０ｎ、１１０ｓを周方向に連結した寸法と同程度である。弓形磁石２１０は、ラジアル配向により、磁粉粒子の磁化容易軸が軸Ｚｃへ向くように配向される。そして、弓形磁石２１０は、ラジアル配向を施された後、幅方向中心ＣＬで区画される弓形磁石２１０の一方である第１部分２１０ｎがＮ極に着磁され、他方である第２部分２１０ｓがＳ極に着磁される。このような弓形磁石２１０を、例えば、電動機のロータに組み付けると、第１部分２１０ｎ及び第２部分２１０ｓからの磁束は、いずれも軸Ｚｃへ向かうので、電動機のそれぞれのティースＴＳを通過する磁束量が少なくなる。その結果、ティースＴＳが利用できる磁束密度は、図６に示す弓形磁石１１０ｎ、１１０ｓよりも低下する。 7 is approximately the same as the dimension in which the arcuate magnets 110n and 110s illustrated in FIG. 6 are connected in the circumferential direction. The arcuate magnet 210 is oriented by radial orientation so that the easy axis of magnetization of the magnetic powder particles faces the axis Zc. The arcuate magnet 210 is subjected to radial orientation, and then the first portion 210n, which is one of the arcuate magnets 210 defined by the center CL in the width direction, is magnetized to the N pole, and the second portion 210s, which is the other. The S pole is magnetized. When such an arcuate magnet 210 is assembled to a rotor of an electric motor, for example, the magnetic flux from the first portion 210n and the second portion 210s is directed to the axis Zc, so that the amount of magnetic flux passing through each tooth TS of the electric motor Less. As a result, the magnetic flux density that can be used by the teeth TS is lower than that of the arcuate magnets 110n and 110s shown in FIG.
　上述したように、本実施形態においては、弓形磁石１０の磁粉粒子の磁化容易軸が配向する方向は、軸Ｚｃａ、Ｚｃｂに向かって集束している。このため、弓形磁石１０が着磁されると、弓形磁石１０のからの磁束は、第１部分１０ｎにおいて軸Ｚｃａに向かい、第２部分１０ｓにおいて軸Ｚｃｂに向かう。このような弓形磁石１０を、例えば、電動機のロータに組み付けると、第１部分１０ｎからの磁束と第２部分１０ｓからの磁束とが、電動機のそれぞれのティースＴＳに向かうので、それぞれのティースＴＳ通過する磁束の量は弓形磁石２１０よりも多くなる。その結果、ティースＴＳが利用できる磁束密度は、図７に示す弓形磁石２１０よりも増加する。 As described above, in the present embodiment, the direction in which the easy magnetization axes of the magnetic powder particles of the arcuate magnet 10 are oriented is focused toward the axes Zca and Zcb. For this reason, when the arcuate magnet 10 is magnetized, the magnetic flux from the arcuate magnet 10 goes to the axis Zca in the first portion 10n and to the axis Zcb in the second portion 10s. When such an arcuate magnet 10 is assembled to a rotor of an electric motor, for example, the magnetic flux from the first portion 10n and the magnetic flux from the second portion 10s are directed to the respective teeth TS of the electric motor. The amount of magnetic flux to be generated is larger than that of the arcuate magnet 210. As a result, the magnetic flux density that can be used by the teeth TS is larger than that of the arcuate magnet 210 shown in FIG.
　また、図６に示す弓形磁石１１０ｎ、１１０ｓは、電動機のロータに組み込んだ場合、両者の間には周方向に一定の間隔Ｉが生ずる。すなわち、弓形磁石１１０ｎ、１１０ｓは、一対のＮ極とＳ極との組み合わせにおいて、極間に一定の間隔Ｉが生ずる。図５に示すように、本実施形態の弓形磁石１０は、１個の磁石を２極（Ｎ極、Ｓ極）に着磁するので、周方向に向かってＮ極とＳ極とが連続している。このような構造により、図５、図６から分かるように、弓形磁石１０は、１極に着磁したＮ極及びＳ極の弓形磁石１１０ｎ、１１０ｓを周方向に配置する場合とは異なり、極間に一定の間隔Ｉは生じない。このため、弓形磁石１０を用いた場合、ティースＴＳは、幅方向中心ＣＬ付近の領域（中心領域）Ｃからの弓形磁石１０の磁束も利用できる。その結果、ティースＴＳが利用できる磁束密度は、図６に示す弓形磁石１１０ｎ、１１０ｓよりも増加する。次に、弓形磁石１０の表面における磁束密度（表面磁束密度）Ｂｄについて説明する。 Further, when the arcuate magnets 110n and 110s shown in FIG. 6 are incorporated in the rotor of the electric motor, a constant interval I is generated between them in the circumferential direction. In other words, the arcuate magnets 110n and 110s have a constant interval I between the poles in the combination of a pair of N poles and S poles. As shown in FIG. 5, the arcuate magnet 10 of this embodiment magnetizes one magnet to two poles (N pole, S pole), so that the N pole and S pole are continuous in the circumferential direction. ing. As can be seen from FIGS. 5 and 6, the arcuate magnet 10 is different from the case where the N-pole and S-pole arcuate magnets 110 n and 110 s arranged in one pole are arranged in the circumferential direction. There is no fixed interval I between them. For this reason, when the arcuate magnet 10 is used, the teeth TS can also use the magnetic flux of the arcuate magnet 10 from the region (center region) C near the center CL in the width direction. As a result, the magnetic flux density that can be used by the teeth TS is larger than that of the arcuate magnets 110n and 110s shown in FIG. Next, the magnetic flux density (surface magnetic flux density) Bd on the surface of the bow magnet 10 will be described.
　図８、図９は、弓形磁石の表面磁束密度を測定する手法の説明図である。表面磁束密度Ｂｄを測定する場合、図８に示すように、着磁した弓形磁石１０の第１曲面１１の付近にホール素子６を配置する。このときのホール素子６は、第１曲面１１の長さ方向における中央部に位置させて、第１曲面１１に接触させるか、できるだけ接近させて配置する。そして、弓形磁石１０を周方向（図８の矢印ＣＲで示す方向）に回転させることにより、第１曲面１１の周方向における一端ＰＡから他端ＰＢにかけての表面磁束密度Ｂｄの分布が測定される。なお、弓形磁石１０を回転させる場合、ホール素子６と第１曲面１１との距離が変動しないようする。 8 and 9 are explanatory diagrams of a method for measuring the surface magnetic flux density of the bow magnet. When measuring the surface magnetic flux density Bd, as shown in FIG. 8, the Hall element 6 is arranged in the vicinity of the first curved surface 11 of the magnetized bow-shaped magnet 10. The Hall element 6 at this time is positioned at the center of the first curved surface 11 in the length direction, and is placed in contact with the first curved surface 11 or as close as possible. The distribution of the surface magnetic flux density Bd from one end PA to the other end PB in the circumferential direction of the first curved surface 11 is measured by rotating the arcuate magnet 10 in the circumferential direction (the direction indicated by the arrow CR in FIG. 8). . When the arcuate magnet 10 is rotated, the distance between the Hall element 6 and the first curved surface 11 is not changed.
　弓形磁石１０の第２曲面１２の表面磁束密度Ｂｄを測定する場合、図９に示すように、着磁した弓形磁石１０の第２曲面１２の付近にホール素子６を配置する。このときのホール素子６は、第２曲面１２の長さ方向における中央部に位置させて、第２曲面１２に接触させるか、できるだけ接近させて配置する。そして、弓形磁石１０を周方向（図９の矢印ＣＲで示す方向）に回転させることにより、第２曲面１２の周方向における一端ＰＣから他端ＰＤにかけての表面磁束密度Ｂｄの分布が測定される。なお、弓形磁石１０を回転させる場合、ホール素子６と第２曲面１２との距離が変動しないようする。上述したようにして測定された表面磁束密度Ｂｄを、弓形磁石１０の周方向位置に対してプロットすると、表面磁束密度Ｂｄの分布曲線（波形）が得られる。 When measuring the surface magnetic flux density Bd of the second curved surface 12 of the arcuate magnet 10, the Hall element 6 is disposed in the vicinity of the second curved surface 12 of the magnetized arcuate magnet 10, as shown in FIG. The Hall element 6 at this time is positioned at the center of the second curved surface 12 in the length direction, and is placed in contact with the second curved surface 12 or as close as possible. Then, by rotating the arcuate magnet 10 in the circumferential direction (the direction indicated by the arrow CR in FIG. 9), the distribution of the surface magnetic flux density Bd from the one end PC to the other end PD in the circumferential direction of the second curved surface 12 is measured. . When the arcuate magnet 10 is rotated, the distance between the Hall element 6 and the second curved surface 12 is prevented from changing. When the surface magnetic flux density Bd measured as described above is plotted against the circumferential position of the arcuate magnet 10, a distribution curve (waveform) of the surface magnetic flux density Bd is obtained.
　図１０は、本実施形態に係る弓形磁石を１極で着磁した場合における表面磁束密度の波形を示す図である。図１１は、本実施形態に係る弓形磁石と寸法及び形状が同じ弓形磁石をラジアル配向して１極で着磁した場合における表面磁束密度の波形を示す図である。図１２は、本実施形態に係る弓形磁石を１極で着磁した場合の他の例における表面磁束密度の波形を示す図である。図１０から図１２の測定に用いた弓形磁石は、いずれも材料、寸法及び形状は同一であり、磁場配向の方法が異なる。 FIG. 10 is a diagram showing a waveform of the surface magnetic flux density when the arcuate magnet according to this embodiment is magnetized with one pole. FIG. 11 is a diagram showing a waveform of the surface magnetic flux density when an arcuate magnet having the same size and shape as the arcuate magnet according to the present embodiment is radially oriented and magnetized with one pole. FIG. 12 is a diagram showing a waveform of the surface magnetic flux density in another example when the arcuate magnet according to the present embodiment is magnetized with one pole. The arcuate magnets used in the measurements of FIGS. 10 to 12 are all the same in material, size, and shape, and have different magnetic field orientation methods.
　図１０から図１２の横軸は、弓形磁石の周方向位置θ（度）であり、縦軸は表面磁束密度Ｂｄである。周方向位置は、θが９０度及び２７０度を中心としておよそ±４５度の範囲が、弓形磁石１０の第１曲面１１又は第２曲面１２の周方向における範囲である。図１０から図１２の縦軸は、測定値を基準の表面磁束密度で規格化した相対値であるが、基準の表面磁束密度は同じ値なので、それぞれの結果同士を比較することはできる。 10 to 12, the horizontal axis represents the circumferential position θ (degrees) of the arcuate magnet, and the vertical axis represents the surface magnetic flux density Bd. The circumferential position is a range in the circumferential direction of the first curved surface 11 or the second curved surface 12 of the arcuate magnet 10 in the range where θ is about ± 45 degrees centering on 90 degrees and 270 degrees. The vertical axis in FIG. 10 to FIG. 12 is a relative value obtained by normalizing the measured value with the reference surface magnetic flux density. However, since the reference surface magnetic flux density is the same value, the respective results can be compared.
　図１０に示すように、弓形磁石１０を１極で着磁した場合において、弓形磁石１０の表面、すなわち、第１曲面１１と第２曲面１２との少なくとも一方での磁束密度（表面磁束密度）Ｂｄの波形は、弓形磁石１０を構成する複数の磁粉粒子の磁化容易軸の配向方向（磁粉粒子配向方向）が集束する軸（横断面においては点）の数だけピークを有する。第１曲面１１及び第２曲面１２の両方で、それぞれ前記ピークを有する場合、弓形磁石１０の有する前記ピークの数は、前記配向方向が収束する軸の数の２倍になる。例えば、前記配向方向が収束する軸の数が２つである場合、弓形磁石１０の有する前記ピークの数は４つになる。また、第１曲面１１又は第２曲面１２のいずれか一方で前記ピークを有する場合、弓形磁石１０の有する前記ピークの数は、前記配向方向が収束する軸の数に等しくなる。例えば、前記配向方向が収束する軸の数が２つである場合、弓形磁石１０の有する前記ピークの数は２つになる。 As shown in FIG. 10, when the arcuate magnet 10 is magnetized with one pole, the magnetic flux density (surface magnetic flux density) on the surface of the arcuate magnet 10, that is, at least one of the first curved surface 11 and the second curved surface 12. The waveform of Bd has peaks as many as the number of axes (points in the cross section) where the orientation directions (magnet powder particle orientation directions) of the easy magnetization axes of the plurality of magnetic powder particles constituting the arcuate magnet 10 converge. When both the first curved surface 11 and the second curved surface 12 have the peaks, the number of the peaks of the arcuate magnet 10 is twice the number of axes on which the orientation direction converges. For example, when the number of axes on which the orientation direction converges is two, the number of the peaks of the arcuate magnet 10 is four. Moreover, when it has the said peak in either the 1st curved surface 11 or the 2nd curved surface 12, the number of the said peaks which the arcuate magnet 10 has becomes equal to the number of the axis | shafts which the said orientation direction converges. For example, when the number of axes on which the orientation direction converges is two, the number of the peaks of the arcuate magnet 10 is two.
　本実施形態では、前記配向方向が集束する軸は、図３に示すように２つである。図１０に示すように、弓形磁石１０の表面磁束密度Ｂｄの波形は、第１曲面１１においては２つのピークＰｉを有し、第２曲面１２においては２つのピークＰｏを有する。一方、図１１に示すように、図３に示す弓形磁石１０と寸法及び形状が同じ弓形磁石をラジアル配向して１極で着磁した場合、表面磁束密度Ｂｄの波形は一つのピークのみ有する。これは、弓形磁石１０の磁粉粒子配向方向が２つの異なる軸に集束した結果、着磁後における表面磁束密度Ｂｄも、弓形磁石１０の周方向において異なる２箇所で高くなることにより、ピークを形成するためであると考えられる。 In this embodiment, there are two axes on which the orientation direction converges as shown in FIG. As shown in FIG. 10, the waveform of the surface magnetic flux density Bd of the arcuate magnet 10 has two peaks Pi on the first curved surface 11 and two peaks Po on the second curved surface 12. On the other hand, as shown in FIG. 11, when the arcuate magnet having the same size and shape as the arcuate magnet 10 shown in FIG. 3 is radially oriented and magnetized with one pole, the waveform of the surface magnetic flux density Bd has only one peak. This is because, as a result of the magnetic particle orientation direction of the arcuate magnet 10 being focused on two different axes, the surface magnetic flux density Bd after magnetization also increases at two different locations in the circumferential direction of the arcuate magnet 10 to form a peak. It is thought that it is to do.
　図１２に示す例は、磁場配向の条件、より具体的には、磁場成形における磁場を図１０に示す例よりも弱めたものである。この例において、弓形磁石１０の表面磁束密度Ｂｄの波形は、第２曲面１２において２つのピークＰｏを有する。また、弓形磁石１０の第１曲面１１における表面磁束密度Ｂｄの波形は、弓形磁石１０の周方向位置θが９０度近傍、すなわち、幅方向中心に向かって減少し、θ＝９０度近傍で極小値をとる。その過程で、表面磁束密度Ｂｄの波形は、極小値をとる位置を除き、Ｐｖｉで示す位置で前記波形が上に凸になるように、前記波形の曲がる方向が変化する。弓形磁石１０は、弓形磁石１０の磁粉粒子配向方向が集束する軸は２つ存在するため、第１曲面１１の周方向において、磁束密度が異なる２箇所に集中した結果、表面磁束密度Ｂｄの波形は、Ｐｖｉで示す位置において、曲がる方向が変化したと考えられる。 The example shown in FIG. 12 is one in which the magnetic field orientation conditions, more specifically, the magnetic field in magnetic field shaping is weaker than the example shown in FIG. In this example, the waveform of the surface magnetic flux density Bd of the arcuate magnet 10 has two peaks Po on the second curved surface 12. In addition, the waveform of the surface magnetic flux density Bd on the first curved surface 11 of the arcuate magnet 10 is minimal when the circumferential position θ of the arcuate magnet 10 decreases near 90 degrees, that is, toward the center in the width direction, and near θ = 90 degrees. Takes a value. In the process, the waveform of the surface magnetic flux density Bd changes the bending direction of the waveform so that the waveform becomes convex upward at the position indicated by Pvi except for the position where the minimum value is obtained. Since the arcuate magnet 10 has two axes on which the magnetic particle orientation direction of the arcuate magnet 10 converges, the waveform of the surface magnetic flux density Bd is obtained as a result of being concentrated at two different magnetic flux densities in the circumferential direction of the first curved surface 11. Is considered to have changed the direction of bending at the position indicated by Pvi.
　このように、弓形磁石１０は、磁場配向の条件が異なることにより、表面磁束密度Ｂｄの波形が異なることがある。しかし、第１曲面１１と第２曲面１２との少なくとも一方における表面磁束密度Ｂｄの波形は、磁粉粒子配向方向が集束する軸の数だけピークを有する。このように、弓形磁石１０は、第１曲面１１と第２曲面１２との少なくとも一方の周方向における表面磁束密度Ｂｄの波形（分布）が、磁粉粒子配向方向が集束する軸の数だけピークを有する点に特徴がある。 Thus, the waveform of the surface magnetic flux density Bd may differ between the arcuate magnets 10 due to different magnetic field orientation conditions. However, the waveform of the surface magnetic flux density Bd on at least one of the first curved surface 11 and the second curved surface 12 has a peak as many as the number of axes in which the magnetic particle orientation directions converge. As described above, the arcuate magnet 10 has a peak in the waveform (distribution) of the surface magnetic flux density Bd in the circumferential direction of at least one of the first curved surface 11 and the second curved surface 12 by the number of axes on which the magnetic particle orientation direction converges. There is a feature in having.
　図１１に示すように、図３に示す弓形磁石１０と寸法及び形状が同じ弓形磁石をラジアル配向して１極で着磁した場合、表面磁束密度Ｂｄの最高値は、第１曲面１１において６程度である。一方、弓形磁石１０においては、表面磁束密度Ｂｄの最高値は、第１曲面１１におけるピークＰｉの値であり、６．８程度になる。また、弓形磁石１０の表面磁束密度Ｂｄの最小値は、第１曲面１１において６．０程度であり、図１１の弓形磁石と同程度である。 As shown in FIG. 11, when an arcuate magnet having the same size and shape as the arcuate magnet 10 shown in FIG. 3 is radially oriented and magnetized with one pole, the maximum value of the surface magnetic flux density Bd is 6 on the first curved surface 11. Degree. On the other hand, in the bow magnet 10, the maximum value of the surface magnetic flux density Bd is the value of the peak Pi on the first curved surface 11, which is about 6.8. Further, the minimum value of the surface magnetic flux density Bd of the arcuate magnet 10 is about 6.0 on the first curved surface 11, which is the same as that of the arcuate magnet of FIG.
　図１０に示す例と図１１に示す例とでトータルフラックスを比較した。図１１に示す、ラジアル配向して１極で着磁した弓形磁石のトータルフラックスは１７２μＷｂであった。これに対し、図１０に示す例、すなわち、磁粉粒子配向方向を２つの異なる軸に集束させた弓形磁石１０のトータルフラックスは１７７．６μＷｂであった。このように、弓形磁石１０は、ラジアル配向して１極で着磁した弓形磁石に対して、トータルフラックスは約３％向上した。この結果から、弓形磁石１０は、磁場配向の条件を調整して磁粉粒子配向方向が集束する軸の位置を調整することにより、寸法及び形状が同じ弓形磁石１０をラジアル配向した場合よりも、高い表面磁束密度を得ることができるといえる。 The total flux was compared between the example shown in FIG. 10 and the example shown in FIG. The total flux of the arcuate magnet shown in FIG. 11 that is radially oriented and magnetized with one pole was 172 μWb. On the other hand, the total flux of the example shown in FIG. 10, that is, the arcuate magnet 10 in which the magnetic particle orientation directions are focused on two different axes was 177.6 μWb. In this way, the total flux of the arcuate magnet 10 is improved by about 3% compared to the arcuate magnet that is radially oriented and magnetized with one pole. From this result, the arcuate magnet 10 is higher than the case where the arcuate magnet 10 having the same size and shape is radially oriented by adjusting the magnetic field orientation conditions and adjusting the position of the axis where the magnetic particle orientation direction converges. It can be said that the surface magnetic flux density can be obtained.
　図１０に示す例において、弓形磁石１０の第１曲面１１における表面磁束密度Ｂｄは、ピークＰｉの値の絶対値が６．７及び６．９、最小値の絶対値が６．０である。第１曲面１１において、表面磁束密度Ｂｄの波形のピークＰｉと最小値との差の絶対値は、それぞれ０．７、０．９であり、最小値の絶対値の１１．７％、１５％である。また、弓形磁石１０の第２曲面１２における表面磁束密度Ｂｄは、ピークＰｏの値の絶対値がいずれも３．１、最小値の絶対値が３．５である。第２曲面１２において、表面磁束密度Ｂｄの波形のピークＰｏと最小値との差の絶対値は０．４であり、最小値の絶対値の１１．４％である。図１２に示す例において、弓形磁石１０の第２曲面１２における表面磁束密度Ｂｄは、ピークＰｏの値の絶対値がそれぞれ４．２、４．１、最小値の絶対値が４．４５である。第２曲面１２において、表面磁束密度Ｂｄの波形のピークＰｏと最小値との差の絶対値は０．２５、０．３５であり、最小値の絶対値の５．６％、７．８％である。これらの結果から、本実施形態において、弓形磁石１０は、表面磁束密度Ｂｄの波形のピークと最小値との差の絶対値は、最小値の絶対値の５％以上、好ましくは１０％以上あれば、磁粉粒子配向方向を２つの異なる軸に集束させ、有効に利用できる磁束密度の低下を抑制することができる。 In the example shown in FIG. 10, the surface magnetic flux density Bd on the first curved surface 11 of the arcuate magnet 10 has an absolute value of the peak Pi value of 6.7 and 6.9, and an absolute value of the minimum value of 6.0. In the first curved surface 11, the absolute values of the difference between the peak Pi and the minimum value of the waveform of the surface magnetic flux density Bd are 0.7 and 0.9, respectively, and 11.7% and 15% of the absolute value of the minimum value, respectively. It is. Further, regarding the surface magnetic flux density Bd on the second curved surface 12 of the arcuate magnet 10, the absolute value of the peak Po value is 3.1 in all cases, and the absolute value of the minimum value is 3.5. In the second curved surface 12, the absolute value of the difference between the peak Po of the waveform of the surface magnetic flux density Bd and the minimum value is 0.4, which is 11.4% of the absolute value of the minimum value. In the example shown in FIG. 12, the surface magnetic flux density Bd on the second curved surface 12 of the arcuate magnet 10 has an absolute value of the peak Po value of 4.2 and 4.1 and an absolute value of the minimum value of 4.45, respectively. . In the second curved surface 12, the absolute value of the difference between the peak Po and the minimum value of the waveform of the surface magnetic flux density Bd is 0.25 and 0.35, 5.6% and 7.8% of the absolute value of the minimum value. It is. From these results, in this embodiment, the arcuate magnet 10 has an absolute value of the difference between the peak of the surface magnetic flux density Bd waveform and the minimum value of 5% or more, preferably 10% or more of the absolute value of the minimum value. For example, the magnetic particle orientation direction can be focused on two different axes, and a decrease in magnetic flux density that can be effectively used can be suppressed.
　弓形磁石１０を備える電動機は、弓形磁石１０の第１曲面１１が電動機のステータ２６が有するティース２３と対向している。しかし、図１０及び図１２の結果から分かるように、弓形磁石１０は、第２曲面１２においても、表面磁束密度Ｂｄの波形のピークは、周方向において異なる２箇所に存在する。したがって、ステータが有するティースと弓形磁石の外周面とが対向する方式の電動機に対しても、弓形磁石１０を適用すれば、前記ティースが磁束密度を有効に利用できるので好ましい。次に、弓形磁石１０を磁場成形するための磁場成形装置を説明する。 In the electric motor including the arcuate magnet 10, the first curved surface 11 of the arcuate magnet 10 faces the teeth 23 included in the stator 26 of the electric motor. However, as can be seen from the results of FIGS. 10 and 12, the arcuate magnet 10 also has the peak of the waveform of the surface magnetic flux density Bd at two different locations in the circumferential direction even on the second curved surface 12. Therefore, it is preferable to apply the arcuate magnet 10 to an electric motor in which the teeth of the stator and the outer peripheral surface of the arcuate magnet face each other because the teeth can effectively use the magnetic flux density. Next, a magnetic field shaping apparatus for shaping the arcuate magnet 10 will be described.
　図１３は、本実施形態に係る弓形磁石を磁場成形する磁場成形装置の説明図である。図１４は、本実施形態に係る磁場成形装置が有する成形用金型を示す説明図である。図１、図３等に示す弓形磁石１０は、磁場成形装置５０によって磁場中で成形（磁場成形）され、この成形体を焼結することによって製造される。磁場成形装置５０は、型枠５１と、第１パンチ５２と、第２パンチ５３と、磁場発生用コイル５５とを含む。磁場成形装置５０は、型枠５１と第１パンチ５２と第２パンチ５３とで囲まれる成形空間５４内の磁粉粒子ＣＰｍ（図１４参照）を加圧して、円弧状の形状に成形する。型枠５１と、第１パンチ５２と、第２パンチ５３とが、弓形磁石１０を磁場成形する際の成形用金型５０Ｍとなる。 FIG. 13 is an explanatory diagram of a magnetic field shaping apparatus for magnetic field shaping of an arcuate magnet according to the present embodiment. FIG. 14 is an explanatory view showing a molding die included in the magnetic field molding apparatus according to the present embodiment. The arcuate magnet 10 shown in FIGS. 1, 3 and the like is manufactured by being molded (magnetic field molding) in a magnetic field by a magnetic field molding device 50 and sintering this molded body. The magnetic field forming device 50 includes a mold 51, a first punch 52, a second punch 53, and a magnetic field generating coil 55. The magnetic field forming device 50 pressurizes the magnetic powder particles CPm (see FIG. 14) in the forming space 54 surrounded by the mold 51, the first punch 52, and the second punch 53 to form an arc shape. The mold 51, the first punch 52, and the second punch 53 serve as a molding die 50M when the arcuate magnet 10 is magnetically molded.
　型枠５１は、強磁性体であり、シリンダ部５１Ｃを有する。シリンダ部５１Ｃは、断面が矩形、すなわち、弓形磁石１０の平面視の形状である貫通孔である。本実施形態においては、シリンダ部５１Ｃの一方の開口に第１パンチ５２が配置される。第２パンチ５３は、シリンダ部５１Ｃの他方の開口からシリンダ部５１Ｃの内部へ進入している。本実施形態において、第１パンチ５２は鉛直方向とは反対側（上方）に配置され、第２パンチ５３は鉛直方向側（下方）に配置される。成形空間５４は、型枠５１、すなわち型枠５１のシリンダ部５１Ｃと第１パンチ５２と第２パンチ５３とで囲まれる空間である。 The mold 51 is a ferromagnetic body and has a cylinder part 51C. The cylinder part 51 </ b> C is a through hole having a rectangular cross section, that is, a shape of the arcuate magnet 10 in a plan view. In the present embodiment, the first punch 52 is disposed in one opening of the cylinder portion 51C. The second punch 53 enters the cylinder portion 51C from the other opening of the cylinder portion 51C. In the present embodiment, the first punch 52 is disposed on the opposite side (upward) from the vertical direction, and the second punch 53 is disposed on the vertical direction side (lower). The molding space 54 is a space surrounded by the mold 51, that is, the cylinder portion 51 </ b> C of the mold 51, the first punch 52, and the second punch 53.
　磁場成形時においては、シリンダ部５１Ｃの内部に磁粉粒子ＣＰｍを投入し、第１パンチ５２をシリンダ部５１Ｃの一方の開口に配置する。そして、磁場発生用コイル５５によって成形空間５４内の磁粉粒子ＣＰｍに磁界を印加しながら、第２パンチ５３を第１パンチ５２側に進入させて（図１３の矢印Ｐで示す方向）、成形空間５４内の磁粉粒子ＣＰｍを加圧する。このような処理によって、磁粉粒子ＣＰｍは磁界中で加圧されるので、前記磁界の方向に磁粉粒子ＣＰｍの磁化容易軸が配向しながら、横断面が円弧形状に成形される。このようにして得られた磁粉粒子の成形体を焼結することにより、弓形磁石１０を得ることができる。 At the time of magnetic field shaping, magnetic powder particles CPm are introduced into the cylinder portion 51C, and the first punch 52 is disposed in one opening of the cylinder portion 51C. Then, while applying a magnetic field to the magnetic powder particles CPm in the molding space 54 by the magnetic field generating coil 55, the second punch 53 enters the first punch 52 side (in the direction indicated by the arrow P in FIG. 13) to form the molding space. The magnetic powder particles CPm in 54 are pressurized. By such treatment, the magnetic powder particles CPm are pressurized in a magnetic field, so that the easy axis of magnetization of the magnetic powder particles CPm is oriented in the direction of the magnetic field, and the cross section is formed into an arc shape. By sintering the magnetic powder particle compact thus obtained, the bow-shaped magnet 10 can be obtained.
　第１パンチ５２は、磁粉粒子ＣＰｍと接する成形面５２ａを有する非磁性体５２Ｎと、非磁性体５２Ｎの成形面５２ａとは反対側（成形空間５４側）で非磁性体５２Ｎと接する強磁性体５２Ｍとを含む。すなわち、非磁性体５２Ｎは、成形面５２ａとは反対側で強磁性体５２Ｍと接する。第２パンチ５３は、磁粉粒子ＣＰｍと接する成形面５３ａを有する非磁性体５３Ｎと、非磁性体５３Ｎの成形面５３ａとは反対側（成形空間５４側）で非磁性体５３Ｎと接し、かつ非磁性体５３Ｎと接する部分に、非磁性体５３Ｎに向かって突出する凸部５６を少なくとも２つ有する強磁性体５３Ｍとを含む。すなわち、非磁性体５３Ｎは、成形面５３ａとは反対側で強磁性体５３Ｍと接する。このような構造により、磁場成形装置５０の第１パンチ５２が有する非磁性体５２Ｎと、第２パンチ５３が有する非磁性体５３Ｎとは、型枠５１のシリンダ部５１Ｃ内で対向している。凸部５６の数は、図１、図３等に示す弓形磁石１０の磁粉粒子配向方向が集束する軸の数に対応しており、２個に限定されるものではない。凸部５６の形状は、曲面形状である。 The first punch 52 includes a non-magnetic body 52N having a molding surface 52a in contact with the magnetic powder particles CPm, and a ferromagnetic body in contact with the non-magnetic body 52N on the side opposite to the molding surface 52a of the non-magnetic body 52N (molding space 54 side). 52M. That is, the nonmagnetic material 52N is in contact with the ferromagnetic material 52M on the side opposite to the molding surface 52a. The second punch 53 is in contact with the nonmagnetic body 53N having a molding surface 53a in contact with the magnetic powder particles CPm, and on the side opposite to the molding surface 53a of the nonmagnetic body 53N (molding space 54 side). A portion in contact with the magnetic body 53N includes a ferromagnetic body 53M having at least two protrusions 56 protruding toward the nonmagnetic body 53N. That is, the nonmagnetic material 53N is in contact with the ferromagnetic material 53M on the side opposite to the molding surface 53a. With such a structure, the nonmagnetic body 52N included in the first punch 52 of the magnetic field forming apparatus 50 and the nonmagnetic body 53N included in the second punch 53 face each other in the cylinder portion 51C of the mold 51. The number of the convex portions 56 corresponds to the number of axes on which the magnetic particle orientation directions of the arcuate magnet 10 shown in FIGS. 1 and 3 are focused, and is not limited to two. The shape of the convex portion 56 is a curved surface shape.
　本実施形態において、第１パンチ５２が有する非磁性体５２Ｎの成形面５２ａは、弓形磁石１０の第２曲面１２を形成する。また、第２パンチ５３が有する非磁性体５３Ｎの成形面５３ａは、弓形磁石１０の第１曲面１１を形成する。このため、成形面５２ａは、弓形磁石１０の第２曲面１２を転写した形状、すなわち凹形の曲面形状であり、成形面５３ａは、弓形磁石１０の第１曲面１１を転写した形状、すなわち凸形の曲面形状である。 In this embodiment, the molding surface 52a of the nonmagnetic body 52N of the first punch 52 forms the second curved surface 12 of the arcuate magnet 10. Further, the molding surface 53 a of the nonmagnetic material 53 </ b> N included in the second punch 53 forms the first curved surface 11 of the arcuate magnet 10. Therefore, the molding surface 52a is a shape obtained by transferring the second curved surface 12 of the arcuate magnet 10, that is, a concave curved surface shape, and the molding surface 53a is a shape obtained by transferring the first curved surface 11 of the arcuate magnet 10, ie, a convex shape. The curved shape of the shape.
　第２パンチ５３が有する強磁性体５３Ｍは、曲面形状の凸部５６を２つ有することにより、成形用金型５０Ｍ内の磁束をそれぞれの凸部５６、５６に向かわせることができる。その結果、弓形磁石１０を構成する複数の磁粉粒子の磁化容易軸は、図３に示す２つの異なる軸Ｚｃａ、Ｚｃｂに向かって集束するようになる。このような作用によって、磁場成形装置５０は、図３に示すような、第１曲面１１の内側に存在する２つの異なる軸Ｚｃａ、Ｚｃｂに向かって磁粉粒子配向方向が集束する弓形磁石１０を得ることができる。また、成形空間５４内に、第１パンチ５２の非磁性体５２Ｎと第２パンチ５３の非磁性体５３Ｎとを対向して配置し、磁場成形中においては磁粉粒子ＣＰｍと接するようにすることにより、弓形磁石１０の配向が第１曲面１１又は第２曲面１２に集束することを抑制できる。凸部５６の曲面の曲率半径や頂点の位置等は、磁粉粒子配向方向が集束する軸の位置に応じて適宜調整される（以下同様）。 The ferromagnetic body 53M of the second punch 53 has two curved convex portions 56, so that the magnetic flux in the molding die 50M can be directed to the convex portions 56 and 56, respectively. As a result, the easy magnetization axes of the plurality of magnetic particle particles constituting the arcuate magnet 10 are focused toward two different axes Zca and Zcb shown in FIG. By such an action, the magnetic field shaping device 50 obtains an arcuate magnet 10 in which the magnetic particle orientation directions converge toward two different axes Zca and Zcb existing inside the first curved surface 11 as shown in FIG. be able to. Further, the non-magnetic body 52N of the first punch 52 and the non-magnetic body 53N of the second punch 53 are arranged to face each other in the molding space 54 so as to be in contact with the magnetic powder particles CPm during the magnetic field molding. The orientation of the arcuate magnet 10 can be prevented from converging on the first curved surface 11 or the second curved surface 12. The curvature radius of the curved surface of the convex portion 56, the position of the apex, and the like are appropriately adjusted according to the position of the axis where the magnetic particle orientation direction converges (the same applies hereinafter).
　強磁性体で作られる型枠５１及び強磁性体５２Ｍ、５３Ｍの材料は特に限定されず、一般に用いられるものであればよい。例えば、炭素鋼、炭素工具鋼、合金工具鋼、ダイス鋼等が型枠５１及び強磁性体５２Ｍ、５３Ｍの材料として用いられる。非磁性体５２Ｎ、５３Ｎの材料は特に限定されず、ステライト（登録商標）、ステンレス鋼、銅ベリリウム合金、ハイマンガン鋼、青銅、真鍮、非磁性超鋼等を用いることができる。 The material of the mold 51 and the ferromagnets 52M and 53M made of a ferromagnet is not particularly limited as long as it is generally used. For example, carbon steel, carbon tool steel, alloy tool steel, die steel or the like is used as the material of the mold 51 and the ferromagnetic bodies 52M and 53M. The material of the nonmagnetic materials 52N and 53N is not particularly limited, and Stellite (registered trademark), stainless steel, copper beryllium alloy, high manganese steel, bronze, brass, nonmagnetic super steel, or the like can be used.
　また、第１パンチ５２と第２パンチ５３とのいずれか一方は、強磁性体のみを有し、磁場成形中において強磁性体が磁粉粒子ＣＰｍと接するようにしてもよい。すなわち、本実施形態においては、第１パンチ５２と第２パンチ５３との少なくとも一方が、非磁性体を有していればよい。このようにすると、図１３に示す磁場発生用コイル５５が発生する磁場の強さを変更せずに、磁場配向の条件を変更することができる。このため、第１パンチ５２と第２パンチ５３との少なくとも一方が、非磁性体を有するようにすると、磁場配向の条件を変更する際の自由度が高くなる。その結果、製造する弓形磁石１０の特性に応じて、磁場配向の条件を容易に変更することができる。例えば、図１２に示す例の弓形磁石は、第１パンチ５２を強磁性体５２Ｍのみとして磁場成形して得られたものである。なお、第１パンチ５２と第２パンチ５３との少なくとも一方が非磁性体を有する場合、非磁性体と接する強磁性体は、非磁性体と接する部分に、非磁性体に向かって突出する凸部を少なくとも２つ有するようにする。第１パンチ５２と第２パンチ５３との少なくとも一方が、非磁性体を有する場合、非磁性体と接する強磁性体は、非磁性体に向かって突出する凸部を少なくとも２つ有する。 Further, either one of the first punch 52 and the second punch 53 may have only a ferromagnetic material, and the ferromagnetic material may be in contact with the magnetic powder particles CPm during magnetic field forming. That is, in the present embodiment, at least one of the first punch 52 and the second punch 53 only needs to have a nonmagnetic material. In this way, the magnetic field orientation conditions can be changed without changing the strength of the magnetic field generated by the magnetic field generating coil 55 shown in FIG. For this reason, when at least one of the first punch 52 and the second punch 53 has a non-magnetic material, the degree of freedom in changing the magnetic field orientation condition is increased. As a result, the magnetic field orientation conditions can be easily changed according to the characteristics of the arcuate magnet 10 to be manufactured. For example, the arcuate magnet of the example shown in FIG. 12 is obtained by forming a magnetic field using only the first punch 52 as the ferromagnetic body 52M. When at least one of the first punch 52 and the second punch 53 has a nonmagnetic material, the ferromagnetic material in contact with the nonmagnetic material protrudes toward the nonmagnetic material at the portion in contact with the nonmagnetic material. Have at least two parts. When at least one of the first punch 52 and the second punch 53 has a nonmagnetic material, the ferromagnetic material in contact with the nonmagnetic material has at least two convex portions that protrude toward the nonmagnetic material.
　図１５は、本実施形態に係る磁場成形装置が有する成形要金型の変形例を示す説明図である。この成形用金型５０Ｍａは、第２曲面１２（図２参照）の外側に存在する２つの異なる軸に向かって磁粉粒子配向方向を集束させた弓形磁石１０を得るためのものである。この成形用金型５０Ｍａは、型枠５１が有するシリンダ部５１Ｃの一方の開口に配置される第１パンチ５２ａが有する強磁性体５２Ｍａが、非磁性体５２Ｎａに向かって突出する凸部５７を２つ有する。また、第２パンチ５３ａは、非磁性体５３Ｎａと、非磁性体５３Ｎの成形空間５４側で非磁性体５３Ｎと接する強磁性体５３Ｍａとを含んでいる。そして、他方の開口からシリンダ部５１Ｃ内に第２パンチ５３ａが進入する。 FIG. 15 is an explanatory view showing a modification of the molding die required for the magnetic field molding apparatus according to this embodiment. The molding die 50Ma is for obtaining an arcuate magnet 10 in which the magnetic particle orientation directions are converged toward two different axes existing outside the second curved surface 12 (see FIG. 2). In the molding die 50Ma, the ferromagnetic body 52Ma included in the first punch 52a disposed in one opening of the cylinder portion 51C included in the mold 51 has two protrusions 57 projecting toward the nonmagnetic body 52Na. Have one. The second punch 53a includes a nonmagnetic material 53Na and a ferromagnetic material 53Ma in contact with the nonmagnetic material 53N on the molding space 54 side of the nonmagnetic material 53N. Then, the second punch 53a enters the cylinder portion 51C from the other opening.
　このような構造により、第１パンチ５２ａは、成形用金型５０Ｍａ内の磁束をそれぞれの凸部５７、５７に向かわせることができる。その結果、弓形磁石１０を構成する複数の磁粉粒子の磁化容易軸は、第２曲面１２（図２参照）の外側に存在する２つの異なる軸に向かって集束するようになる。この成形用金型５０Ｍａは、第２曲面１２（図２参照）の外側に存在する２つの異なる軸に向かって磁粉粒子配向方向を集束させた弓形磁石１０を成形することができる。 With such a structure, the first punch 52a can direct the magnetic flux in the molding die 50Ma toward the convex portions 57 and 57, respectively. As a result, the easy magnetization axes of the plurality of magnetic particle particles constituting the arcuate magnet 10 are focused toward two different axes existing outside the second curved surface 12 (see FIG. 2). The molding die 50Ma can mold the arcuate magnet 10 in which the magnetic particle orientation directions are converged toward two different axes existing outside the second curved surface 12 (see FIG. 2).
　また、成形用金型５０Ｍａにおいて、第２パンチ５３ａを、図１４示す第２パンチ５３としてもよい。すなわち、成形用金型５０Ｍａは、成形面５３ａを有する非磁性体５３Ｎと、この非磁性体５３Ｎの反成形面側に接触し、かつ非磁性体５３Ｎに向かって突出する凸部５６を少なくとも２つ有する強磁性体５２Ｍとを含む第２パンチ５３を備えてもよい。このようにすれば、弓形磁石１０を構成する複数の磁粉粒子の磁化容易軸は、第１曲面１１の内側に存在する２つの異なる軸及び第２曲面１２の外側に存在する２つの異なる軸に向かって集束するようになる。その結果、このような第１パンチ５２ａ及び第２パンチ５３を有する成形用金型５０Ｍａは、第１曲面１１の内側に存在する２つの異なる軸及び第２曲面１２の外側に存在する２つの異なる軸に向かって磁粉粒子配向方向を集束させた弓形磁石１０を成形することができる。このように、本実施形態においては、第１パンチと第２パンチとの少なくとも一方が有する強磁性体は、非磁性体と接する部分に、非磁性体に向かって突出する凸部を少なくとも２つ有していればよい。 Further, in the molding die 50Ma, the second punch 53a may be the second punch 53 shown in FIG. That is, the molding die 50Ma includes at least two nonmagnetic bodies 53N having a molding surface 53a and convex portions 56 that are in contact with the non-molding surface side of the nonmagnetic body 53N and project toward the nonmagnetic body 53N. You may provide the 2nd punch 53 containing the ferromagnetic material 52M which has one. In this way, the easy magnetization axes of the plurality of magnetic powder particles constituting the arcuate magnet 10 are two different axes existing inside the first curved surface 11 and two different axes existing outside the second curved surface 12. It becomes focused toward. As a result, the molding die 50Ma having the first punch 52a and the second punch 53 has two different axes existing inside the first curved surface 11 and two different shafts existing outside the second curved surface 12. The arcuate magnet 10 in which the magnetic particle orientation direction is focused toward the axis can be formed. As described above, in this embodiment, the ferromagnetic material included in at least one of the first punch and the second punch has at least two convex portions protruding toward the nonmagnetic material at the portion in contact with the nonmagnetic material. It only has to have.
　図１６、図１７は、本実施形態に係る弓形磁石を製造する他の手法を示す説明図である。この手法（製造方法）は、図１、図３等に示す弓形磁石１０の周方向における寸法が半分の部分弓形磁石１０Ｓ、１０Ｓを接合することにより、弓形磁石１０を得るものである。まず、部分弓形磁石１０Ｓ、１０Ｓを製造する。部分弓形磁石１０Ｓ、１０Ｓは、磁場成形においては、それぞれ、ラジアル配向される。このとき、部分弓形磁石１０Ｓ、１０Ｓの磁粉粒子配向方向は、軸Ｚｃａ、Ｚｃｂに集束するようにする。 16 and 17 are explanatory views showing another method for manufacturing the bow magnet according to the present embodiment. In this method (manufacturing method), the arcuate magnet 10 is obtained by joining the partial arcuate magnets 10S and 10S whose dimensions in the circumferential direction of the arcuate magnet 10 shown in FIGS. First, the partial arcuate magnets 10S and 10S are manufactured. The partial arcuate magnets 10S and 10S are each radially oriented in the magnetic field forming. At this time, the magnetic particle orientation directions of the partial arcuate magnets 10S and 10S are focused on the axes Zca and Zcb.
　磁場成形が終了した部分弓形磁石１０Ｓ、１０Ｓは、それぞれの側面１０ＳＰ、１０ＳＰ同士で接合される。この接合には、例えば、エポキシ系の接着剤が用いられる。部分弓形磁石１０Ｓ、１０Ｓ同士が接着されると、弓形磁石１０ａが完成する。この弓形磁石１０は、第１曲面１１ａの内側に存在する２つの異なる軸Ｚｃａ、Ｚｃｂに向かって磁粉粒子配向方向が集束する。このように、弓形磁石１０は、ラジアル配向させた複数の部分弓形磁石１０Ｓ、１０Ｓを接合することによっても製造することができる。したがって、この手法によれば、上述した成形用金型５０Ｍ、５０Ｍａを用いないでも、弓形磁石１０を製造することができる。 The partial arcuate magnets 10S and 10S that have been subjected to the magnetic field shaping are joined to each other at the side surfaces 10SP and 10SP. For this bonding, for example, an epoxy adhesive is used. When the partial arcuate magnets 10S and 10S are bonded together, the arcuate magnet 10a is completed. The arcuate magnet 10 converges in the magnetic particle orientation direction toward two different axes Zca and Zcb existing inside the first curved surface 11a. Thus, the arcuate magnet 10 can also be manufactured by joining a plurality of radially oriented partial arcuate magnets 10S, 10S. Therefore, according to this method, the arc-shaped magnet 10 can be manufactured without using the molding dies 50M and 50Ma described above.
　以上、本実施形態に係る弓形磁石は、長さ方向と直交する面で切った横断面において、弓形磁石が有する複数の磁粉粒子は、磁化容易軸の配向方向が、少なくとも２つの点に集束するようにするとともに、集束する点の数と同じ極の数（本実施形態では２）に着磁する。このようにすることで、本実施形態に係る弓形磁石から、これに対向する電動機のティースへ向けて磁束を集中させることができる。その結果、本実施形態に係る弓形磁石は、１極に着磁した弓形磁石をＮ極、Ｓ極と交互に配列した場合と比較して、ティースが利用できる磁束密度を同等以上とすることができる。 As described above, in the arcuate magnet according to the present embodiment, in the cross section cut by the plane orthogonal to the length direction, the plurality of magnetic particle particles included in the arcuate magnet are focused on at least two points in the orientation direction of the easy magnetization axis. In addition, the number of poles is the same as the number of points to be focused (2 in this embodiment). By doing in this way, magnetic flux can be concentrated from the bow-shaped magnet which concerns on this embodiment toward the teeth of the electric motor which opposes this. As a result, the arcuate magnet according to the present embodiment can make the magnetic flux density available to the teeth equal to or greater than that in the case where the arcuate magnets magnetized to one pole are alternately arranged with the N pole and the S pole. it can.
　また、本実施形態に係る弓形磁石は、１極に着磁した弓形磁石をＮ極、Ｓ極と交互に配列して用いる場合の弓形磁石を周方向に２個連結した寸法の弓形磁石であり、１個の弓形磁石を２極に着磁して用いる。このため、本実施形態に係る弓形磁石を電動機に用いた場合、１極に着磁した弓形磁石をＮ極、Ｓ極と交互に配列して用いる場合と比較して、弓形磁石を電動機に組み付ける作業を軽減できるので、電動機の生産性が向上するとともに、製造コストも低減できる。 The arcuate magnet according to the present embodiment is an arcuate magnet having a size in which two arcuate magnets are connected in the circumferential direction when arcuate magnets magnetized to one pole are alternately arranged with N and S poles. One bow magnet is used with two poles. For this reason, when the arcuate magnet according to the present embodiment is used for an electric motor, the arcuate magnet is assembled to the electric motor as compared with the case where the arcuate magnets magnetized to one pole are alternately arranged with N and S poles. Since the work can be reduced, the productivity of the electric motor can be improved and the manufacturing cost can be reduced.
　また、本実施形態に係る弓形磁石を電動機に用いた場合、１極に着磁した弓形磁石をＮ極、Ｓ極と交互に配列して用いる場合と比較して、使用する弓形磁石の個数を半分にすることができる。弓形磁石を磁場成形で製造する場合、弓形磁石の寸法が変化しても、磁場成形に要する時間はほぼ同じである。このため、１台の電動機に使用する弓形磁石の個数を半分にできるということは、１台の電動機に用いるすべての弓形磁石を製造する時間を約半分にできることになる。 Further, when the bow magnet according to the present embodiment is used in an electric motor, the number of bow magnets to be used is smaller than that in the case where arc magnets magnetized on one pole are alternately arranged with N poles and S poles. Can be halved. When an arcuate magnet is manufactured by magnetic field shaping, the time required for magnetic field shaping is almost the same even if the dimensions of the arcuate magnet change. For this reason, the fact that the number of arcuate magnets used in one electric motor can be halved means that the time for manufacturing all the arcuate magnets used in one electric motor can be halved.
　また、弓形磁石がフェライト焼結磁石である場合、必要な形状及び寸法を得るために、焼結後に研磨が必要である。この研磨は、通常、弓形磁石を、その長さ方向に向かって研磨装置へ送る。すなわち、研磨においては、研磨装置を通過する弓形磁石の総長さが研磨に要する時間に比例する。電動機に使用する弓形磁石の個数を半分にできるということは、１台の電動機に用いるすべての弓形磁石が研磨装置に通過する個数を半分にできるということである。したがって、本実施形態に係る弓形磁石は、１極に着磁した弓形磁石をＮ極、Ｓ極と交互に配列して用いる場合と比較して、研磨装置を通過する弓形磁石の総長さも半分にできるので、研磨に要する時間を約半分にすることができる。 Also, when the arcuate magnet is a ferrite sintered magnet, polishing is necessary after sintering in order to obtain the necessary shape and dimensions. In this polishing, the arcuate magnet is usually sent to the polishing apparatus along its length. That is, in polishing, the total length of the arcuate magnet that passes through the polishing apparatus is proportional to the time required for polishing. The fact that the number of arcuate magnets used in an electric motor can be halved means that the number of all arcuate magnets used in a single electric motor can be halved. Therefore, the arcuate magnet according to the present embodiment halves the total length of the arcuate magnet passing through the polishing apparatus as compared with the case where the arcuate magnets magnetized to one pole are alternately arranged with N poles and S poles. As a result, the time required for polishing can be halved.
　さらに、完成した弓形磁石は検査され、検査に合格したものが梱包され、製品として出荷される。１台の電動機に使用する弓形磁石の個数を半分にできるということは、検査する弓形磁石の数を半分にできるということである。このため、検査に要する時間は半減するので、弓形磁石の生産性は向上するとともに、検査員の負担も軽減される。また、１台の電動機に使用する弓形磁石の個数を半分にできるので、１極に着磁した弓形磁石をＮ極、Ｓ極と交互に配列して用いる場合と比較して、１台の電動機分の弓形磁石を梱包する梱包材の量も低減できる。このため、本実施形態に係る弓形磁石は、環境負荷も低減できる。このように、本実施形態に係る弓形磁石は、１極に着磁した弓形磁石をＮ極、Ｓ極と交互に配列して用いる場合と比較して、生産性の向上及び製造コストの低減を図ることができるとともに、検査員の負担及び環境負荷も低減できるという利点がある。 Furthermore, the completed bow magnets are inspected, and those that pass the inspection are packed and shipped as products. The fact that the number of arcuate magnets used in a single electric motor can be halved means that the number of arcuate magnets to be inspected can be halved. For this reason, since the time required for the inspection is reduced by half, the productivity of the bow magnet is improved and the burden on the inspector is reduced. In addition, since the number of arcuate magnets used in one electric motor can be halved, one electric motor can be used as compared with the case where arcuate magnets magnetized in one pole are alternately arranged in N and S poles. It is also possible to reduce the amount of packing material for packing the minute bow-shaped magnet. For this reason, the arcuate magnet according to the present embodiment can reduce the environmental load. As described above, the bow magnet according to the present embodiment improves the productivity and reduces the manufacturing cost as compared with the case where the arc magnet magnetized to one pole is alternately arranged with the N pole and the S pole. There is an advantage that the burden on the inspector and the environmental load can be reduced.
　１０、１０ａ、１１０、１１０ｎ、１１０ｓ、２１０　弓形磁石
　１０ｎ、２１０ｎ　第１部分
　１０ｓ、２１０ｓ　第２部分
　１０Ｓ　部分弓形磁石
　１１、１１ａ　第１曲面
　１２　第２曲面
　１３、１３Ａ、１３Ｂ、１３、Ｃ、１３Ｄ　側面
　２１、２７、３２、３２ａ、１２１　ロータ
　２２、１２２　ステータコア
　２２ａ　ヨーク
　２３、１２３、ＴＳ　ティース
　２４、１２４　導線
　２６、３１、３６ａ　ステータ
　２７Ｓ、３２Ｓ　シャフト
　２７Ｃ、３２Ｃ、３３　ロータコア
　３０、３０ａ　電動機
　３５　磁石挿入スロット
　３６、３６Ｔ　ティース
　３６Ｙ　ヨーク
　３７　コイル
　３７ａ　励磁コイル
　５０　磁場成形装置
　５０Ｍ、５０Ｍａ　成形用金型
　５１Ｃ　シリンダ部
　５１　型枠
　５２、５２ａ　第１パンチ
　５２Ｍ、５２Ｍａ　強磁性体
　５２Ｎ、５２Ｍａ　非磁性体
　５２ａ　成形面
　５３、５３ａ　第２パンチ
　５３Ｍ、５３Ｍａ　強磁性体
　５３Ｎ、５３Ｎａ　非磁性体
　５３ａ　成形面
　５４　成形空間
　５５　磁場発生用コイル
　５６、５７　凸部 10, 10a, 110, 110n, 110s, 210 Arcuate magnet 10n, 210n First part 10s, 210s Second part 10S Partial arcuate magnet 11, 11a First curved surface 12 Second curved surface 13, 13A, 13B, 13, C, 13D Sides 21, 27, 32, 32a, 121 Rotor 22, 122 Stator core 22a Yoke 23, 123, TS teeth 24, 124 Conductor 26, 31, 36a Stator 27S, 32S Shaft 27C, 32C, 33 Rotor core 30, 30a Electric motor 35 Magnet insertion Slot 36, 36T Teeth 36Y Yoke 37 Coil 37a Excitation coil 50 Magnetic field forming device 50M, 50Ma Mold 51C Cylinder part 51 Mold 52, 52a First punch 52M, 52Ma Ferromagnetic material 52N, 52Ma Non-magnetic material 52a Form surface 53,53a second punch 53M, 53 mA ferromagnetic 53N, 53Na nonmagnetic 53a forming surface 54 forming space 55 a magnetic field generating coil 56, 57 protrusion

Claims (4)

  1. 　複数の磁粉粒子を含む磁石であり、
    　当該磁石の長さ方向と直交する面で切った横断面において、前記複数の磁粉粒子は、磁化容易軸の配向方向が、少なくとも２つの点に集束するように配向されていることを特徴とする弓形磁石。     A magnet including a plurality of magnetic powder particles,
    In the cross section cut by a plane orthogonal to the length direction of the magnet, the plurality of magnetic powder particles are oriented such that the orientation direction of the easy axis of magnetization is focused on at least two points. Bow magnet.
  2. 　請求項１に記載の弓形磁石を１極で着磁した場合において、当該弓形磁石の前記横断面における形状が円弧形状の第１曲面と、当該第１曲面の外側に対向して配置されるとともに前記横断面における形状が円弧形状の第２曲面との少なくとも一方での磁束密度の波形は、前記配向方向が集束する点の数だけピークを有する弓形磁石。 When the arcuate magnet according to claim 1 is magnetized with one pole, the arcuate magnet is disposed so that the cross-sectional shape of the arcuate magnet is opposed to the arc-shaped first curved surface and the outside of the first curved surface. The waveform of the magnetic flux density on at least one of the second curved surface having an arc shape in the cross section has an arcuate magnet having peaks as many as the number of points where the orientation directions converge.
  3. 　前記波形の前記ピークと最小値との差の絶対値は、前記最小値の絶対値の５％以上である請求項２に記載の弓形磁石。 The arcuate magnet according to claim 2, wherein the absolute value of the difference between the peak and the minimum value of the waveform is 5% or more of the absolute value of the minimum value.
  4. 　型枠と、第１パンチと、第２パンチとを含み、前記型枠と前記第１パンチと前記第２パンチとで囲まれる成形空間内の磁粉粒子を加圧して、円弧状の形状に成形する磁場成形用金型であり、
    　前記第１パンチと前記第２パンチとの少なくとも一方は、
    　前記磁粉粒子と接する成形面を有する非磁性体と、
    　前記非磁性体の前記成形面とは反対側で前記非磁性体と接し、かつ前記非磁性体と接する部分に、前記非磁性体に向かって突出する凸部を少なくとも２つ有する強磁性体と、
    　を有することを特徴とする磁場成形用金型。     The magnetic powder particles in the molding space including the mold frame, the first punch, and the second punch, and surrounded by the mold frame, the first punch, and the second punch are pressed into a circular arc shape. A magnetic field molding die
    At least one of the first punch and the second punch is:
    A non-magnetic material having a molding surface in contact with the magnetic powder particles;
    A ferromagnetic body having at least two convex portions projecting toward the non-magnetic body at a portion in contact with the non-magnetic body on a side opposite to the molding surface of the non-magnetic body and in contact with the non-magnetic body; ,
    A magnetic field molding die characterized by comprising:
PCT/JP2011/070631 2010-09-10 2011-09-09 Arched magnet and magnetic field molding die WO2012033202A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201180043091.1A CN103098354B (en) 2010-09-10 2011-09-09 Arc magnet and magnetic forming mould

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2010-203620 2010-09-10
JP2010203620 2010-09-10

Publications (1)

Publication Number Publication Date
WO2012033202A1 true WO2012033202A1 (en) 2012-03-15

Family

ID=45810797

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2011/070631 WO2012033202A1 (en) 2010-09-10 2011-09-09 Arched magnet and magnetic field molding die

Country Status (3)

Country Link
JP (1) JP5870567B2 (en)
CN (1) CN103098354B (en)
WO (1) WO2012033202A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016189238A1 (en) 2015-05-22 2016-12-01 Saint-Gobain Glass France Laminated glazing comprising a profiled bead for snap-fitting with an additional polymer ribbon and profiled bead

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5722944B2 (en) * 2013-04-26 2015-05-27 株式会社日本製鋼所 Manufacturing method of plastic magnet
US9583244B2 (en) * 2014-09-30 2017-02-28 Nichia Corporation Bonded magnet, bonded magnet component, and bonded magnet production method
JP6706487B2 (en) 2015-11-19 2020-06-10 日東電工株式会社 Rotating electric machine equipped with a rotor having a rare earth permanent magnet
CN113785473A (en) * 2019-03-11 2021-12-10 西门子歌美飒可再生能源公司 Magnet assembly including magnet devices each having a focused magnetic domain alignment pattern

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4995116A (en) * 1973-01-16 1974-09-10
JPS5710729U (en) * 1980-06-20 1982-01-20
JP2002110417A (en) * 2000-09-29 2002-04-12 Toda Kogyo Corp Anisotropic segmental magnet and motor provided therewith
JP2009142144A (en) * 2007-11-12 2009-06-25 Panasonic Corp Anisotropic permanent magnet motor

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5772305A (en) * 1980-10-24 1982-05-06 Tdk Corp Permanent magnet composition with patterned magnetization
JPH0620826A (en) * 1991-11-26 1994-01-28 Kawasaki Steel Corp Focus oriented magnet and metallic mold for manufacturing the same
JPH07212994A (en) * 1994-01-24 1995-08-11 Toshiba Corp Permanent-magnet motor
JPH0995116A (en) * 1995-10-02 1997-04-08 Nittetsu Semiconductor Kk Article carrying vehicle
JP4057092B2 (en) * 1997-03-24 2008-03-05 Ｔｄｋ株式会社 Dry magnetic field molding equipment for arc-shaped ferrite magnets
JP3697375B2 (en) * 1999-12-17 2005-09-21 Ｔｄｋ株式会社 Mold for magnetic field molding of ferrite magnets for DC motors
CN1162235C (en) * 2000-03-28 2004-08-18 住友特殊金属株式会社 Powder pressing appts. and method for producing rere earch alloyed magnetic powder formed body
JP4826704B2 (en) * 2003-10-15 2011-11-30 日立金属株式会社 Pole-concentrated magnetic circuit and magnetic separation device
EP1830451A4 (en) * 2004-12-17 2016-03-23 Hitachi Metals Ltd Rotor for motor and method for producing the same
WO2009001801A1 (en) * 2007-06-28 2008-12-31 Hitachi Metals, Ltd. R-tm-b radial anisotropic ring magnet, process for production of the same, metal mold for producing the same, and rotor for brushless motor
JP2009043926A (en) * 2007-08-08 2009-02-26 Kaneka Corp Magnet roller

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4995116A (en) * 1973-01-16 1974-09-10
JPS5710729U (en) * 1980-06-20 1982-01-20
JP2002110417A (en) * 2000-09-29 2002-04-12 Toda Kogyo Corp Anisotropic segmental magnet and motor provided therewith
JP2009142144A (en) * 2007-11-12 2009-06-25 Panasonic Corp Anisotropic permanent magnet motor

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016189238A1 (en) 2015-05-22 2016-12-01 Saint-Gobain Glass France Laminated glazing comprising a profiled bead for snap-fitting with an additional polymer ribbon and profiled bead

Also Published As

Publication number Publication date
JP5870567B2 (en) 2016-03-01
CN103098354B (en) 2016-05-04
JP2012080097A (en) 2012-04-19
CN103098354A (en) 2013-05-08

Similar Documents

Publication Publication Date Title
US8039998B2 (en) Rotor for motor and method for producing the same
JP5870567B2 (en) Bow magnets and magnetic field molds
JP6308205B2 (en) Method for manufacturing anisotropic magnet, method for manufacturing anisotropic soft magnetic material, and method for manufacturing rotor of rotating electrical machine
JP2005184916A (en) Dust core and stator core
JP2010183684A (en) Permanent magnet type rotor for rotary machine
JP2006304472A (en) Ring magnet, and manufacturing apparatus and manufacturing method thereof
WO2021200361A1 (en) Power generation element, magnetic sensor using same, encoder, and motor
JP2003257762A (en) Ring magnet, manufacturing method therefor, rotor, rotating machine, magnetic field generating apparatus therefor, and ring magnet manufacturing apparatus
US11069464B2 (en) Method and assembly for producing a magnet
JP4507208B2 (en) Magnet rotor and rotation angle detection apparatus using the same
JP4029679B2 (en) Bond magnet for motor and motor
JP5766134B2 (en) Shaft type linear motor mover, permanent magnet, linear motor
JP2010193587A (en) Magnet magnetization device for rotors, and motor
JP2018050045A (en) Sintered magnet
JP2009111418A (en) Die, molding machine and method used for manufacturing anisotropic magnet, and magnet manufactured thereby
JP7081145B2 (en) Magnet structure, rotation angle detector and electric power steering device
JP4985342B2 (en) Method and apparatus for magnetizing permanent magnet
WO2011061806A1 (en) Method of manufacturing rotor of electric motor
US20180145548A1 (en) Magnetic field generating member and motor including same
JP2006014436A (en) Motor
JP2006261236A (en) Mold for molding anisotropy magnet, method of manufacturing anisotropy magnet, anisotropy magnet and motor using it
JP5177661B2 (en) Torque sensor
JP2010148309A (en) Field element and manufacturing method of the same
JPH06260328A (en) Cylindrical anisotropic magnet and manufacture thereof
JP2005210803A (en) Manufacturing method of arc-shaped permanent magnet and manufacturing method of embedded magnet type rotor

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 201180043091.1

Country of ref document: CN

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 11823676

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 11823676

Country of ref document: EP

Kind code of ref document: A1