JP2013219911A - Rare earth permanent magnet, manufacturing method for rare earth permanent magnet, and motor - Google Patents

Abstract

A rare earth permanent magnet capable of reducing eddy current is provided.
SOLUTION: A dividing fault 2 is formed extending from one outer surface 1a perpendicular to the orientation direction A of a rare earth permanent magnet 1 to the other outer surface 1b. It consists of the same element group as the element group constituting the permanent magnet 1, the electrical resistance of the dividing layer 2 is formed higher than the electrical resistance of the rare earth permanent magnet 1, and the separation layer 2 is in an amorphous alloy at the portion in contact with the rare earth permanent magnet 1. 2a, and the inside of the amorphous alloy 2a is constituted by a recrystallized permanent magnet 2b having an easy magnetization axis direction in a direction orthogonal to the orientation direction of the rare earth permanent magnet 1.
[Selection] Figure 1

Description

  The present invention relates to a rare earth permanent magnet, a method of manufacturing a rare earth permanent magnet, and a motor that can realize reduction of eddy current of the permanent magnet and improvement of motor characteristics.

  Conventionally, in a motor using permanent magnets, a plurality of permanent magnets are arranged as magnetic poles on the rotor. And it supplies with electricity to the coil at the side of the stator which provided the space | gap and is arrange | positioned so as to oppose a rotor, a rotating magnetic field is formed, and a rotor is rotated. In recent years, rare earth permanent magnets such as R—Fe—B sintered magnets having higher magnetic properties are often used as permanent magnets for the purpose of miniaturization and higher efficiency of motors. However, since rare earth permanent magnets have lower electrical resistance than ferrite magnets and bonded magnets, in motors that are driven at high speeds of several thousand to several tens of thousands of revolutions per minute, eddy currents generated in the permanent magnets can reduce motor efficiency, Thermal demagnetization due to heat generation of the permanent magnet due to eddy current is a problem. In order to solve this problem, conventionally, as a means for reducing eddy currents generated in a permanent magnet, there is a method of laminating and integrating a plurality of insulated permanent magnet pieces (for example, see Patent Document 1). As another conventional method, there is a method in which a plurality of slits are provided in a permanent magnet to reduce the effective cross-sectional area (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 4-79741 JP 2000-295804 A

  In the conventional permanent magnet, the permanent magnet pieces are individually bonded and integrated using a jig or the like, so that the work process becomes complicated. In addition, in order to bond a plurality of magnets, it is necessary to individually perform machining for shape finishing, which complicates the operation and increases the processing cost. In addition, there is a problem that the dimensional accuracy of the permanent magnet after integration is deteriorated due to a dimensional error of a plurality of magnets or an assembly error at the time of bonding. Moreover, since it is necessary to shape | mold a some magnet, shaping | molding cost increases. When one large block-shaped magnet is manufactured in order to reduce the molding cost, there is a problem that the permanent magnet needs to be cut and the processing cost increases.

  In the later conventional permanent magnets, slits are formed by cutting the grooves on the magnet surface with an inner or outer cutter or wire saw, etc., but when forming slits with a multi-wire saw, etc. There is a problem that the processing is complicated, such as the speed is low and the wire is cut during processing.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a rare earth permanent magnet, a method for manufacturing a rare earth permanent magnet, and a motor that reduce eddy currents generated in the permanent magnet. .

This invention
A rare earth permanent magnet,
Having a dividing layer formed extending from the outer surface on one side orthogonal to the orientation direction of the rare earth permanent magnet toward the other outer surface;
The dividing layer is composed of the same element group as the element group constituting the rare earth permanent magnet,
The electric resistance of the dividing layer is higher than that of the rare earth permanent magnet.

In addition, the method for producing a rare earth permanent magnet of the present invention includes:
An irradiation line is irradiated from the outer surface on one side perpendicular to the orientation direction of the rare earth permanent magnet to irradiate the dividing line forming portion to melt the rare earth permanent magnet, and then the molten part is cooled to form the dividing line. is there.

The motor of the present invention
In a motor comprising a rotating shaft and a rotating iron core inserted around the rotating shaft,
The rotating iron core is provided with the rare earth permanent magnet according to any one of claims 1 to 6.

This invention
A rare earth permanent magnet,
Having a dividing layer formed extending from the outer surface on one side orthogonal to the orientation direction of the rare earth permanent magnet toward the other outer surface;
The dividing layer is composed of the same element group as the element group constituting the rare earth permanent magnet,
Since the electric resistance of the dividing fault is formed higher than the electric resistance of the rare earth permanent magnet,
The eddy current of the rare earth permanent magnet can be reduced.

In addition, the method for producing a rare earth permanent magnet of the present invention includes:
Since the rare earth permanent magnet is melted by irradiating the dividing line formation location from one outer surface perpendicular to the orientation direction of the rare earth permanent magnet to melt the rare earth permanent magnet, and then forming the dividing line by cooling the melting part.
A rare earth permanent magnet that reduces eddy current can be obtained.

The motor of the present invention
In a motor comprising a rotating shaft and a rotating iron core inserted around the rotating shaft,
Since the rare earth permanent magnet according to any one of claims 1 to 6 is disposed in the rotating iron core,
Rare earth permanent magnets that reduce eddy currents can improve motor characteristics.

It is the perspective view which showed the structure of the rare earth permanent magnet in Embodiment 1 of this invention. It is sectional drawing which showed the structure of the rare earth permanent magnet shown in FIG. It is the perspective view which showed the manufacturing method of the rare earth permanent magnet shown in FIG. It is the figure which showed the structure of the motor using the rare earth permanent magnet shown in FIG. It is the figure which showed the structure of the other motor using the rare earth permanent magnet shown in FIG. It is the figure which showed the example of arrangement | positioning of the rare earth permanent magnet in the motor using the rare earth permanent magnet shown in FIG. It is the figure which showed the structure of the other rare earth permanent magnet in Embodiment 1 of this invention. It is the figure which showed the structure of the other rare earth permanent magnet in Embodiment 1 of this invention. It is the figure which showed the structure of the other rare earth permanent magnet in Embodiment 1 of this invention. It is the figure which showed the structure of the other rare earth permanent magnet in Embodiment 1 of this invention. It is the figure which showed the structure of the other rare earth permanent magnet in Embodiment 1 of this invention. It is the figure which showed the structure of the rare earth permanent magnet in Embodiment 2 of this invention.

Embodiment 1 FIG.
Embodiments of the present invention will be described below. 1 is a perspective view showing a configuration of a rare earth permanent magnet according to Embodiment 1 of the present invention, FIG. 2 is a sectional view and an enlarged sectional view showing a section of the rare earth permanent magnet shown in FIG. 1, and FIG. It is the perspective view which showed the manufacturing method of the rare earth permanent magnet shown in FIG. In the drawing, a rare earth permanent magnet 1 is continuously arranged from one outer surface 1a perpendicular to the orientation direction A of the rare earth permanent magnet 1 to the other outer surface 1b and parallel to the orientation direction A. A plurality of dividing lines 2 are formed continuously from 1c toward the other outer surface 1d. The dividing fault 2 is composed of the same element group as the element group constituting the rare earth permanent magnet 1, and the electric resistance of the dividing fault 2 is formed higher than the electric resistance of the rare earth permanent magnet 1.

  In the first embodiment, specifically, as shown in FIG. 2, the dividing line 2 is formed of a portion in contact with the rare earth permanent magnet 1 with an amorphous alloy 2a, and the inside of the amorphous alloy 2a is a rare earth permanent magnet. It is formed of a recrystallized permanent magnet 2b having an easy magnetization axis direction B in a direction perpendicular to the orientation direction A of 1. Further, the rare earth permanent magnet 1 specifically has an R-MB system composition (R is one or more selected from rare earth elements including Y and Sc, M is Fe, or Fe and Co. It is formed of a rare earth sintered magnet made of a transition metal as a main component.

  Next, a method for manufacturing the rare earth permanent magnet according to the first embodiment configured as described above will be described. First, the rare earth permanent magnet 1 is processed into a predetermined shape in advance by the following method for use in a motor or the like. Alloy for rare earth permanent magnet 1 having an RMB system composition (R is one or more selected from rare earth elements including Y and Sc, and M is a transition metal mainly composed of Fe or Fe and Co) Is manufactured by strip casting. Next, the strip cast alloy obtained by the strip cast method is made hydrogen embrittled and then made into a fine powder having an average particle diameter of about 3 to 5 μm by jet mill pulverization using an inert gas such as nitrogen gas.

  Next, the obtained fine powder is filled into a cavity constituted by a mold, and compression molded using a servo press, a hydraulic press or the like in a magnetic field to obtain a molded body. Next, the molded body is heat-treated, that is, sintered at a temperature of 1000 to 1100 ° C. in vacuum or argon gas. Next, an aging treatment is performed at about 400 to 600 ° C. in order to further increase the coercive force. Next, the rare earth permanent magnet 1 manufactured by such a method is finally subjected to grinding by machining so as to have a predetermined shape.

  Next, the rare earth permanent magnet 1 is placed in a vacuum chamber, and as shown in FIG. 3, an electron beam 7 as an irradiation line is irradiated to form a dividing layer 2. The electron beam 7 is deflected by the deflection coil and moves at high speed. As shown in FIG. 3, the electron beam 7 is disposed so as to be perpendicular to the orientation direction A of the rare earth permanent magnet 1 (z direction in FIG. 3), and the spot of the electron beam 7 is on the xy plane. Irradiate to draw a trajectory. And the formation area of the dividing layer 2 of the rare earth permanent magnet 1 irradiated with the electron beam 7 is heated to 1400 ° C. or more and melted.

  Since the electron beam 7 rapidly moves while melting a part of the rare earth permanent magnet 1, the melted region is deprived of heat by transferring heat to the entire rare earth permanent magnet 1, and immediately cooled rapidly. Will be. At this time, if the energy of the electron beam 7 is too large, the melted region becomes wider than necessary, and the energy that the electron beam 7 supplies to the rare earth permanent magnet 1 with respect to the volume of the rare earth permanent magnet 1, that is, the heat capacity. Is too large, heat transfer is not sufficiently performed, and recrystallization causes no amorphous alloy 2a to be obtained. Therefore, more preferably, the rare earth permanent magnet 1 itself may be arranged in a copper mold having a high thermal conductivity before the electron beam 7 is irradiated so that the heat transfer is sufficiently performed.

  The electron beam 7 used for melting the rare earth permanent magnet 1 has an acceleration voltage of 60 kV, a beam current of 10 mA, a beam deflection speed of 2 m / min, and a spot diameter of about 0.2 mm. The smaller the spot diameter is, the easier it is to concentrate the energy, so that the melting width of the melted portion is reduced, the amorphized region and the recrystallized region are small, and the deterioration of the magnetic properties of the entire rare earth permanent magnet 1 is suppressed Can do. Moreover, if the deflection speed of the electron beam 7 is too slow, not only does the melting region widen and the magnetic properties of the entire rare earth permanent magnet 1 deteriorate significantly, but the entire rare earth permanent magnet 1 is not sufficiently dissipated and the cooling speed is increased. Becomes slow, and the amorphous alloy 2a cannot be generated.

  If the beam deflection speed is too high, the energy for melting the rare earth permanent magnet 1 is insufficient, and the rare earth permanent magnet 1 is not melted. In the case of the present invention, melting of the rare earth permanent magnet 1, that is, the Nd—Fe—B alloy was observed in the region of the beam deflection speed of 0.2 to 50 m / min at an acceleration voltage of 60 keV and a beam current of 10 mA. The condition of the electron beam 7 is not limited to the condition implemented in the present invention, and can be freely selected as long as the rare earth permanent magnet 1, that is, the Nd—Fe—B alloy can be melted.

  At this time, as shown in FIG. 2 (a), the surface from one outer surface 1a perpendicular to the orientation direction A of the rare earth permanent magnet 1 to the orientation direction A toward the other outer surface 1b (that is, “orientation” In the cross section of “surface parallel to direction A”), the rare-earth permanent magnet 1 is melted by irradiation with the electron beam 7, and the other outer surface located on the extension line in the irradiation direction from the outer surface 1a (irradiation surface) on one side. The region that is gradually melted toward the surface 1b becomes narrower.

  Further, as shown in FIG. 2 (b), which is a partially enlarged view of FIG. 2 (a), the melted Nd—Fe—B is formed from an unmelted Nd—Fe—B alloy located on both sides of the penetration. Deprived of heat, it crystallizes in a direction perpendicular to the orientation direction A. In this process, the melted Nd—Fe—B in the vicinity of the interface between the melted part and the non-melted part is rapidly cooled at 10,000 to 1,000,000 ° C./s to become an amorphous alloy 2a. The thickness of the amorphous alloy 2a formed at this time is about 5 to 50 μm. As shown above, specifically, if the electron beam 7 supplies too much energy to the rare earth permanent magnet 1, Nd—Fe—B does not conduct heat sufficiently and is 10000 ° C./s or less. Thus, the amorphous alloy 2a cannot be formed.

  Then, crystallization gradually proceeds from the interface toward the melted portion. Since the recrystallized Nd—Fe—B crystallizes in the direction orthogonal to the alignment direction A, it has a major axis in the direction orthogonal to the alignment direction A, and the alignment direction A (that is, the irradiation beam of the electron beam 7) The main phase and Nd-rich phase of Nd—Fe—B having a short axis in the parallel direction) are generated. Thus, the region melted and recrystallized by irradiating the electron beam 7 in the direction (parallel direction) extending from the outer surface 1a on one side orthogonal to the orientation direction A toward the other outer surface 1b is Since the crystal growth direction is perpendicular to the orientation direction A, the crystal orientation is aligned in the direction orthogonal to the irradiation direction of the electron beam 7, and the easy magnetization axis is aligned in the direction orthogonal to the irradiation direction of the electron beam 7. In other words, the recrystallized permanent magnet 2b is oriented with the easy axis direction in the direction orthogonal to the orientation direction A of the rare earth permanent magnet 1.

  The size of the rare earth permanent magnet 1 used at this time is 45 mm × 30 mm × thickness 5 mm, and the dividing layer 2 penetrates the depth of 5 mm. In the rare earth permanent magnet 1 that is too thick, it is necessary to increase the energy given to the rare earth permanent magnet 1 by the electron beam 7, the bead width becomes wide, the melted region is not cooled sufficiently, and the split layer 2 is generated. The region that is not the rare earth permanent magnet 1 becomes wider and the magnetic properties of the entire rare earth permanent magnet 1 are deteriorated. In Embodiment 1 of the present invention, good results were obtained in the generation of the dividing fault 2 by melting and quenching with the rare earth permanent magnet 1 having a thickness of about 20 mm or less. In addition, the number of times the electron beam 7 is scanned on the xy axis of the rare earth permanent magnet 1 may not be one, and in order to improve heat dissipation, both surfaces of the rare earth permanent magnet 1 in the thickness direction, the outer surface 1a on one side, and Alternatively, the electron beam 7 may be irradiated from both sides of the other outer surface 1b to form the dividing layer 2 in two steps.

  And according to this Embodiment 1, when the electron beam is irradiated once so that the rare earth permanent magnet 1 of 45 mm x 30 mm x thickness 5mm may be divided (that is, the dividing line 2 is formed only in one place in FIG. ), The electric resistance before the formation of the dividing layer 2 (before irradiation with the electron beam 7) was 1.3 to 1.6 μm, whereas the electric resistance after the formation of the dividing layer 2 (after irradiation with the electron beam 7). Was 0.05-0.20 mΩm. In order to further reduce the eddy current, the dividing line 2 may be formed so that the rare earth permanent magnet 1 is divided into three or more by irradiating the electron beam 7 to a plurality of places.

  Since the amorphous alloy 2a formed in the dividing layer 2 does not have a crystal structure, the easy magnetization axes of the magnets are not aligned. That is, it is not oriented and crystal magnetic anisotropy cannot be obtained. This means that a coercive force cannot be obtained, and the magnetic properties of the amorphous alloy 2a show soft magnetism. If the thickness of the amorphous alloy 2a is too large, the volume of the magnet that generates magnetic flux is reduced, and the amount of magnetic flux and squareness obtained at the time of final use are reduced. Here, the squareness is represented by a squareness ratio. In the demagnetization curve representing the magnetic characteristics of the rare earth permanent magnet 1, the applied magnetic field Hk when Br is 90%, and Hk / when the coercive force is Hcj. Hcj is called a squareness ratio, which is about 0.9 to 0.97 for a normal magnet, and has the same level in this embodiment.

  Next, the rare earth permanent magnet 1 formed in this way is used for a motor. An example will be described. 4 is a cross-sectional view and a top view showing the configuration of the motor using the rare earth permanent magnet shown in FIG. 1, and FIG. 5 is a cross sectional view showing the configuration of another motor using the rare earth permanent magnet shown in FIG. FIG. 6 is a top view showing an arrangement example of the rare earth permanent magnet in the motor using the rare earth permanent magnet shown in FIG. In the figure, the motor includes a rotating shaft 4, a rotating iron core 5 formed by laminating electromagnetic steel plates with the rotating shaft 4 being centered, and a plurality of fittings provided at equal intervals in the circumferential direction of the rotating iron core 5. And a plurality of rare earth permanent magnets 1 disposed in the holes.

  As shown in FIGS. 4 and 5, the plurality of rare earth permanent magnets 1 provided on the rotating iron core 5 are eight, and the magnetic poles generated on the outer peripheral surface of the motor of the rare earth permanent magnet 1 are alternately arranged in the circumferential direction. Since N and S poles are generated, the number of magnetic poles is 8. In the first embodiment, the number of magnetic poles is eight. However, the number of magnetic poles is not limited to this and may be a multiple of two. As shown in FIG. 4, the rare earth permanent magnet 1 is arranged so that the dividing layer 2 is parallel to the rotation axis 4, or the direction in which the rotation axis 4 is divided as shown in FIG. May be provided.

  4 and 5 show an example in which one rare earth permanent magnet 1 is arranged for one magnetic pole. For example, as shown in FIG. Two rare earth permanent magnets 1 are arranged on the magnetic pole, or three rare earth permanent magnets 1 are arranged on one magnetic pole so as to generate the same magnetic pole on the outer peripheral surface as shown in FIG. Also good. In FIG. 6, the description of the dividing fault 2 is omitted.

  Next, suppression of eddy current will be described. The eddy current is a current generated on the conductor surface in a direction that prevents the magnetic flux change. This eddy current is generated in such a direction that an alternating magnetic field is applied to the rare earth permanent magnet 1 incorporated in the rotor and energized by energizing the coil of the stator and rotating the rotor. At this time, the rare earth permanent magnet 1 is not only applied with an alternating magnetic field by the number of rotor poles × the number of rotations, but also included in the distortion of the magnetic flux of the rotor and the distortion of the magnetic flux accompanying the shape accuracy of the stator. The harmonic component is applied to the rare earth permanent magnet 1 as a high frequency alternating magnetic field, an eddy current is induced in the surface layer of the rare earth permanent magnet 1, the rare earth permanent magnet 1 generates heat, and the rare earth permanent magnet 1 is thermally demagnetized. There was a problem. In the first embodiment, the dividing fault 2 reduces the eddy current flowing through the rare earth permanent magnet 1 and suppresses heat generation of the rare earth permanent magnet 1 to prevent thermal demagnetization.

  In such a motor, the eddy current flowing through the rare earth permanent magnet 1 prevents the magnetic flux generated from the stator from passing through the rare earth permanent magnet 1. Eddy current increases. Accordingly, since the magnetic flux increases as the distance from the coil wound around the stator becomes shorter, the eddy current is larger in the region of the rare earth permanent magnet 1 near the stator. Therefore, in order to obtain a further eddy current reduction effect, the dividing line 2 is formed in a direction parallel to the direction in which the magnetic flux generated by the stator passes through the rare earth permanent magnet 1 (with the orientation direction A of the rare earth permanent magnet 1). It is desirable that the direction is from the outer surface 1a on one side orthogonal to the other outer surface 1b.

  In addition, it is desirable that the surface on which the dividing line 2 is formed is arranged so as to face the stator. In the first embodiment, an example of an inner rotor (a rare earth permanent magnet 1 is arranged on a rotor having a rotating shaft 4 and a coil wound around an armature existing on the outer periphery of the rotor is arranged) is shown. Although shown, the outer rotor (the rotating shaft 4 side is an armature and the rare earth permanent magnet 1 is arranged on the outer periphery) may be used, and the coil and the rare earth permanent facing each other (facing the direction of the rotating shaft 4 face each other). The magnet 1 may be disposed).

  According to the rare earth permanent magnet of the first embodiment configured as described above, since there exists a split layer having a higher electric resistance than the electric resistance of the rare earth permanent magnet (base material), the rare earth permanent magnet flows. The eddy current can be reduced and the heat generation of the rare earth permanent magnet can be suppressed. Moreover, in order to realize this, since it is not necessary to divide the magnet that has undergone the shape finishing process by mechanical cutting or the like, there is little variation in the position and shape of each magnet piece. Therefore, there is little variation in magnetic characteristics between the plurality of rare earth permanent magnets used in the motor.

  In addition, even when the dividing line is formed through the rare earth permanent magnet, there is no connection part that is not electrically separated such as slit processing having the connection part, so that the eddy current is further reduced. be able to. In addition, since the permanent magnet is connected by a magnet material of an amorphous alloy and a recrystallized permanent magnet, the space of the slit portion is made of resin or adhesive to increase the mechanical strength like a slit-processed magnet. It is not necessary to fill and reinforce, and it is not necessary to complicate the assembly process of the magnet or the rotor, so that the work process is not complicated.

  Furthermore, when disassembling the rotor in which the rare earth permanent magnet is disposed, reusing the elements contained in the rare earth permanent magnet, or performing melting, separation and generation for reuse as the rare earth permanent magnet, Since there is no organic substance such as an adhesive, it is not necessary to remove the organic substance for causing the characteristic deterioration of the rare earth permanent magnet, and the reuse process is not complicated. Moreover, when such an organic substance is contained, carbon is contained, and carbon becomes a factor that lowers magnetic properties, particularly saturation magnetic flux density and coercive force. Moreover, since eddy current can be reduced and self-heating during motor driving can be suppressed, the temperature of the permanent magnet during motor driving can be reduced. Therefore, the amount of high-priced elements such as Dy (dysprosium) and Tb (terbium) for improving heat resistance can be reduced, and the raw material price for producing rare earth permanent magnets can be reduced. The unit price of can be reduced.

  In the first embodiment, the example in which the dividing line is configured by the amorphous alloy and the recrystallized permanent magnet has been described. However, the present invention is not limited to this, and the dividing line is configured only by the amorphous alloy. There are also cases where In that case, specifically, in the Nd—Fe—B based sintered magnet, Zr and Co are added, and the cooling rate is lowered to 1 to 100 ° C./s, thereby forming the entire dividing layer with an amorphous alloy. be able to. Thereby, the area | region with high electrical resistance increases, and the reduction effect of an eddy current is acquired further.

  In the first embodiment, an example is shown in which the dividing fault 2 penetrates in the xy plane and the xz plane, and the dividing fault 2 is formed so as to divide the rare earth permanent magnet 1. However, the present invention is not limited to this. For example, as shown in FIGS. 7A and 7B, the dividing line 2 may be formed so as not to penetrate in the xy plane and the xz plane. If only the reduction of eddy current is considered, it is more effective to form it so as to be divided.

  In the first embodiment, an example in which the dividing layer 2 is formed in parallel in the xy plane and the xz plane has been described. However, the present invention is not limited to this, and FIGS. 8A and 8B show the examples. As shown, the dividing layer 2 may be formed so as to be inclined in the xy plane and the xz plane. Even the rare earth permanent magnet 1 having such a configuration can provide the same effects as those of the first embodiment.

  In the first embodiment, the example in which the rare earth permanent magnet 1 is formed in a rectangular parallelepiped is shown. However, the present invention is not limited to this. For example, a “kamaboko type” as shown in FIG. 9B, a “roof-shaped”, a “radial anisotropic ring magnet” as shown in FIG. 9C, and a “polar anisotropic ring magnet” as shown in FIG. 9D. It can be formed similarly. Even the rare earth permanent magnet 1 having such a configuration can provide the same effects as those of the first embodiment. 9C and 9D are oriented as shown in the top view of the rare earth permanent magnet 1 shown on the right side of each drawing.

  In the first embodiment, the split layer 2 formed extending from the outer surface 1a on one side perpendicular to the orientation direction A of the rare earth permanent magnet 1 toward the other outer surface 1b is used as the rare earth permanent magnet. Although the example which comprises from the one outer surface 1c parallel to the orientation direction A of the magnet 1 to the other outer surface 1d is shown, it is not limited to this, and as shown in FIG. A dividing line 2 is formed continuously from one outer surface 1e parallel to the orientation direction A of the permanent magnet 1 to the other outer surface 1f, and the dividing line 2 is formed on one side perpendicular to the orientation direction A of the rare earth permanent magnet 1. On the outer surface 1a, you may cross | intersect and comprise. If comprised in this way, an eddy current can be reduced further.

  In the first embodiment, the example in which the splitting layer 2 is formed by irradiating the single rare earth permanent magnet 1 with the electron beam 7 is not limited to this, but as shown in FIG. The first rare earth permanent magnet 10 and the second rare earth permanent magnet 11 are brought into contact with each other, the contact portion 30 is irradiated with an electron beam, and the contact portion 30 is melted and rapidly cooled to generate the split layer 2 on the contact surface. The plurality of first and second rare earth permanent magnets 10 and 11 may be integrally joined to form the rare earth permanent magnet 1. Even the rare earth permanent magnet 1 having such a configuration can provide the same effects as those of the first embodiment.

  In the first embodiment, the example in which the electron beam 7 is used as the irradiation beam for melting the rare earth permanent magnet 1 is shown. However, the present invention is not limited to this, and the spot diameter is small and the rare earth permanent magnet 1 is used. As long as the irradiation beam can be melted and rapidly cooled, other irradiation beam such as a laser may be used. However, the electron beam 7 has a larger penetration depth per output and a smaller bead width (melting cross-sectional area) than a laser or the like, and the melted region is sufficiently cooled to easily produce an amorphous alloy and a rare earth element. Since the area of the tomogram that is not the permanent magnet 1 can be narrowed, it is preferable that the electron beam 7 is used.

  In the first embodiment, the dividing line 2 is formed in two places as shown in FIG. 1. However, the present invention is not limited to this, and if even one dividing line exists, A reduction effect can be obtained. Moreover, the same effect can be produced at three or more locations.

Embodiment 2. FIG.
FIG. 12 is a cross-sectional view showing a configuration of a rare earth permanent magnet according to Embodiment 2 of the present invention. In the figure, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. In the present second embodiment, the part of the split layer 2 in contact with the rare earth permanent magnet 1 is made of an oxide or an amorphous alloy 20a containing fluoride, and the inside of the amorphous alloy 20a is the orientation of the rare earth permanent magnet 1 It has an easy axis direction in the direction orthogonal to the direction A, and is composed of a recrystallized permanent magnet 20b containing an oxide or fluoride.

  Next, a method for manufacturing the rare earth permanent magnet according to the second embodiment configured as described above will be described. First, as in the first embodiment, a rare earth permanent magnet 1 is prepared in which a Nd—Fe—B strip cast alloy is subjected to hydrogen embrittlement, fine pulverization, forming in a magnetic field, sintering, aging, and shape finishing by machining. . Next, a fluorine compound containing at least one alkali metal element, alkaline earth metal element, or rare earth element, or oxide is slurried with alcohol or the like and applied to the rare earth permanent magnet 1. Here, specifically, Li, Mg, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Zn, Al, Ga, Sr, Y, Zr, Nb, Ag, In, Sn, Sn, Ba , La, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Pb, Bi, Si, and other fluorides or oxides.

  Further, the method of applying the oxide or fluoride 21 to the surface of the rare earth permanent magnet 1 is not limited to the slurry form, and a sputtering method or the like may be used. Here, after making CaO powder into a slurry form and applying it to the surface of the rare earth permanent magnet 1, it is set in a vacuum chamber and irradiated with the electron beam 7 as in the first embodiment (FIG. 12A). ). In the region irradiated with the electron beam 7, the Nd—Fe—B rare earth permanent magnet 1 is melted and the CaO is melted in the Nd—Fe—B alloy as in the first embodiment. It is captured. Since the electron beam 7 moves at a high speed while rapidly melting a part of the rare earth permanent magnet 1, the melted region of the Nd—Fe—B alloy in which CaO is incorporated is transferred to the entire rare earth permanent magnet 1. As a result, heat is deprived and it is rapidly cooled. Then, in the cross section of the plane parallel to the orientation direction A, the melting is caused by the irradiation of the electron beam 7, and the melted Nd—Fe—B is formed from the unmelted Nd—Fe—B alloy located on both sides of the melt. Deprived of heat and crystallizes in a direction perpendicular to the orientation direction.

  In this process, in the second embodiment, the melted Nd—Fe—B in the vicinity of the interface between the melted part and the non-melted part is rapidly cooled to become an oxide or an amorphous alloy 20a containing fluoride, Further, crystallization gradually proceeds from the interface toward the melted portion. The inside of the amorphous alloy 20a has an easy axis direction in a direction perpendicular to the orientation direction A of the rare earth permanent magnet 1, and a recrystallized permanent magnet 20b containing an oxide or fluoride is formed. As described above, the melted portion that has taken in CaO contains CaO even after being recrystallized, and the electrical resistance of the recrystallized region can be increased. The oxide or fluoride applied to the surface of the rare earth permanent magnet 1 is melted or decomposed by heating with the electron beam 7 (FIG. 12B).

  According to the rare earth permanent magnet of the second embodiment configured as described above, the effect similar to that of the first embodiment is obtained, and thus, an oxide, Alternatively, the presence of fluoride increases the electric resistance of the rare earth permanent magnet, and has an effect of reducing eddy current. Further, by including an oxide or fluoride in the amorphous alloy, the electrical resistance of the amorphous alloy is increased, and the eddy current can be further reduced.

  In addition to the region other than the dividing line, the oxide or fluoride component reacts with the main phase of Nd—Fe—B in the rare earth permanent magnet as a whole, but the magnetic properties are lowered. Then, the oxide or fluoride is formed in the dividing layer, and the oxide or fluoride component does not exist in other regions, so that the magnetic property is less deteriorated. Further, the region where the oxide or fluoride is dispersed is not necessarily the region melted by the electron beam, and the oxide or fluoride may be diffused inside the base material of the rare earth permanent magnet by heating. Good. Further, the fluoride or oxide may be diffused in the main phase, but more preferably, the saturation magnetic flux density of the rare earth permanent magnet 1 is lowered if it is diffused only in the crystal grain boundary and not in the main phase. The electrical resistance can be increased without causing it.

  When a rare earth permanent magnet is produced by sintering after preparing a magnet compact by mixing finely pulverized magnet powder with oxide or fluoride powder, the oxide or The fluoride component reacts with the main phase of Nd—Fe—B to lower the magnetic properties. In the present invention, the fluoride or oxide is formed in the dividing line, In the region, since the oxide or fluoride component does not exist, the magnetic property is less deteriorated.

  In the second embodiment, the example in which the dividing layer is formed of a recrystallized permanent magnet and an amorphous alloy containing oxide or fluoride is not limited to this. Even if the split layer is composed only of a recrystallized permanent magnet containing an oxide or fluoride, the same effect as in the second embodiment can be obtained because of its high electric resistance.

  Further, in each of the above embodiments, it is described as being orthogonal to the alignment direction, parallel to the alignment direction, and orthogonal, parallel, or vertical such as perpendicular to the alignment direction, but within the scope where the invention can be implemented. If present, they may be substantially orthogonal, substantially parallel, and substantially vertical.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

1 rare earth permanent magnet, 1a outer surface on one side, 1b outer surface on the other side,
1c, 1e One outer surface, 1d, 1f The other outer surface, bisection fault,
2a, 20a amorphous alloy, 2b, 20b recrystallized permanent magnet, 4 rotating shaft,
5 rotating iron core, 7 electron beam.

Claims (9)

A rare earth permanent magnet,
Having a dividing layer formed extending from the outer surface on one side orthogonal to the orientation direction of the rare earth permanent magnet toward the other outer surface;
The dividing layer is composed of the same element group as the element group constituting the rare earth permanent magnet,
A rare earth permanent magnet having an electric resistance of the dividing layer higher than that of the rare earth permanent magnet. The dividing fault is
Composed of amorphous alloy, or
Whether the portion in contact with the rare earth permanent magnet is made of an amorphous alloy, and the inside of the amorphous alloy is composed of a recrystallized permanent magnet having an easy magnetization axis direction in a direction orthogonal to the orientation direction of the rare earth permanent magnet. Or
It has a magnetization easy axis direction in a direction orthogonal to the orientation direction of the rare earth permanent magnet, and is composed of an oxide or a recrystallized permanent magnet containing fluoride, or
The portion in contact with the rare earth permanent magnet is made of an oxide or an amorphous alloy containing fluoride, and the inside of the amorphous alloy has an easy magnetization axis direction in a direction perpendicular to the orientation direction of the rare earth permanent magnet, The rare earth permanent magnet according to claim 1, which is composed of a recrystallized permanent magnet containing an oxide or a fluoride. The rare earth permanent magnet has an R-MB system composition (R is one or more selected from rare earth elements including Y and Sc, and M is a transition metal mainly composed of Fe or Fe and Co). The rare earth permanent magnet according to claim 1 or 2, wherein the rare earth permanent magnet is formed of a sintered magnet. The rare earth element according to any one of claims 1 to 3, wherein the dividing layer is formed continuously from the outer surface on one side perpendicular to the orientation direction of the rare earth permanent magnet to the outer surface on the other side. permanent magnet. The rare earth permanent according to any one of claims 1 to 4, wherein the dividing layer is configured to be continuous from one outer surface parallel to the orientation direction of the rare earth permanent magnet to the other outer surface. magnet. The rare earth permanent magnet according to any one of claims 1 to 5, wherein the dividing layer is configured to intersect on the outer surface on one side perpendicular to the orientation direction of the rare earth permanent magnet. In the manufacturing method of the rare earth permanent magnet according to any one of claims 1 to 6,
An irradiation line is irradiated from one outer surface perpendicular to the orientation direction of the rare earth permanent magnet to irradiate the dividing line forming portion to melt the rare earth permanent magnet, and then the molten part is cooled to form the dividing line. A method for producing a rare earth permanent magnet. The method for producing a rare earth permanent magnet according to claim 7, wherein an oxide or a fluoride is applied to an outer surface of the rare earth permanent magnet before the irradiation with radiation. In a motor comprising a rotating shaft and a rotating iron core inserted around the rotating shaft,
A motor in which the rare earth permanent magnet according to any one of claims 1 to 6 is disposed on the rotating iron core.

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