JP6536289B2 - Bond magnet, bond magnet piece and method of manufacturing bond magnet - Google Patents

Description

  The present invention relates to a bonded magnet, a bonded magnet piece constituting the same, and a method of manufacturing the bonded magnet.

Permanent magnets are conventionally used in various applications such as motors and speakers. For example, in a small motor, a field coil is disposed in the outer mold, a rotor is disposed inside, and permanent magnets are disposed on the surface (SPM) and inside (IPM) of the rotor. For example, in a small motor of SPM type, in order to obtain larger torque with the same number of magnetic poles and the same size, it is necessary to increase the magnetic flux density of the permanent magnet on the rotor surface. As such a permanent magnet, for example, a sintered magnet using a rare earth element such as Nd ₂ Fe ₁₄ B has been conventionally used.

  On the other hand, conventionally, bonded magnets in which magnet powder is dispersed in plastic and molded are used. Since such a bonded magnet can be molded using a mold such as compression molding or injection molding, it is easy to improve the dimensional accuracy as compared with a sintered magnet, and integration with other members is possible, and further Because it is lightweight, it is used in each field. However, in the bonded magnet, the resin powder as the binder is essential, the limit of mixing the magnet powder is up to about 70% by volume ratio, and it is not possible to escape the reduction of the magnetic property by 30% in calculation, sintered magnet The magnetic force is inferior to that of For example, the energy product is only about 1/3 compared to sintered NdFeB magnets. Therefore, conventionally, bonded magnets have not been generally used for motors that place emphasis on torque. For this reason, a bond magnet having a high magnetic flux density that can be used as a motor or the like has been required.

  Patent documents 1 to 4 disclose various permanent magnets devised to increase the magnetic flux density. However, in these permanent magnets, the magnetic circuit used at the time of molding or orientation was a single magnetic circuit. That is, a closed magnetic circuit (closed circuit) is formed, and the magnetic flux is bent or spread in the magnetic field. According to this method, it is difficult to control the orientation, and even if there is a portion where the magnetic field is weak, the orientation of that portion is not perfect, for example, when using a cylindrical bonded magnet as a motor rotor Magnetic flux becomes extremely low compared to sintered magnets. For this reason, further improvement has been required to cope with applications in which sintered magnets are replaced with bonded magnets.

Japanese Examined Patent Publication No. 6-105644 International Publication WO2012 / 090841 US Patent No. 5019796 JP 10-308308 A

  The present invention has been made in view of the conventional background. One object of the present invention is to provide a bonded magnet having a high magnetic flux density while using a bonded magnet.

Means for Solving the Problems and Effects of the Invention

According to the bond magnet of one aspect of the present invention, the first surface, the second surface in contact with the first surface via the joint portion, and the second surface in contact via the joint portion, and the first surface And a fifth surface which is in contact via the joint portion, wherein the first surface and the fifth surface are inclined at a constant central angle and surrounded by the first surface, the fifth surface and the second surface. A first bonded magnet piece having a fan-shaped outer shape in a sectional view, a first magnetic flux line group extending from the first surface to the second surface, and a third magnetic flux line group extending from the fifth surface to the second surface; A fourth surface that is in contact with the third surface via a bonding portion, and a sixth surface that is in contact with the fourth surface via the bonding portion and being in contact with the third surface via the bonding portion; The third and sixth surfaces are inclined at a constant central angle, and the outer shape in a sectional view surrounded by the third, sixth and fourth surfaces A second bond magnet piece having a fan shape, and a second magnetic flux line group extending from the fourth surface to the third surface, and a fourth magnetic flux line group extending from the fourth surface to the sixth surface; Of the magnetic flux density of the first surface is higher than the magnetic flux density of the first surface, the magnetic flux density of the fourth surface is higher than the magnetic flux density of the third surface, and the magnetic pole of the first surface is different from the magnetic pole of the third surface. The first surface and the third surface are connected, and the second magnetic field line group and the first magnetic field line group are continuous, and the second surface and the fourth plane are connected. Different magnetic poles are exposed to the outside, and the ratio of the length A corresponding to the radius of the sector of the first bonded magnet piece to the length B of the magnetized portion among the portions corresponding to the circular arc When A / B is n = the number of magnetic poles,
In the case of 12 poles or less (central angle θ ₀ 30 30),
0.3184 n ≦ (A / B) <− 0.04 n ³ +1.47 n ² −14.03 n + 43
If it is larger than 12 poles (θ ₀ <30),
0.3184 n ≦ (A / B)
The first bonded magnet piece and the second bonded magnet piece at least include a magnetic material and a resin, and the magnetic material is any of Sm-Co-based, Nd-Fe-B-based and Sm-Fe-N-based. it can be set to either. According to the above configuration, the magnetic flux of the first surface of the first bonded magnet piece is converged at the second surface, and the magnetic flux of the third surface of the second bonded magnet piece is converged at the fourth surface, and a high magnetic flux density is achieved on the working surface Can be realized.

  According to another aspect of the present invention, there is provided a bonded magnet comprising: a first surface; and a second surface in contact with the first surface via a joint portion, the first surface facing the second surface from the first surface A first bond magnet piece having a group of magnetic force lines, a third surface, and a fourth surface in contact with the third surface via a joint portion, and having a second group of magnetic force lines extending from the fourth surface to the third surface A second bond magnet piece, the area of the first surface is larger than the area of the second surface, and the magnetic flux density of the second surface is higher than the magnetic flux density of the first surface; The area of the surface is larger than the area of the fourth surface, and the magnetic flux density of the fourth surface is higher than the magnetic flux density of the third surface, and the magnetic pole of the first surface and the magnetic pole of the third surface are different. The first surface and the third surface are connected, and the second magnetic field line group and the first magnetic field line group are continuous. The magnetic poles different from each other on the two surfaces and the fourth surface are exposed to the outside, the first bonded magnet piece has a flat outer shape, the flat main surface is the first surface, and the flat The side surface in the thickness direction of the shape may be the second surface, and the magnetic lines of force may be bent symmetrically from the first surface toward the second surface inside the first bonded magnet piece. . According to the above configuration, the magnetic flux of the first non-acting surface of the first bonded magnet piece is converged at the first acting surface, and the magnetic flux of the second non-acting surface of the second bonded magnet piece is converged at the second acting surface, A high magnetic flux density can be realized on the working surface.

Furthermore, according to the method of manufacturing a bonded magnet according to another aspect of the present invention, a first non-operating surface, a first operating surface in contact with the first non-operating surface via a joint portion, and the first operating surface And a third non-working surface in contact with the first non-working surface via the bonding part, and the first non-working surface and the third non-working surface at a constant central angle It is a manufacturing method of a bond magnet which makes an outline in a cross sectional view fanned by the 1st non-working surface, the 3rd non-working surface, and the 1st working surface inclined, and which contains a magnetic material and resin. The method comprises the steps of: filling the composition in a cavity of a molding die; and applying an orientation magnetic field to the cavity to form a bonded magnet, wherein the orientation magnetic field is formed by a permanent magnet. A pair of the cavities on the first non-working surface of the bonded magnet A first non-working surface alignment magnet at the location, a third non-working surface alignment magnet at the location corresponding to the third non-working surface, a first working surface alignment magnet at the location corresponding to the first working surface, Are disposed opposite to each other, and the corresponding portions of the first non-working surface alignment magnet and the third non-working surface alignment magnet have the same magnetic pole, and the corresponding ones of the first working surface alignment magnet The magnetic pole is a magnetic pole different from the first non-working surface alignment magnet and the third non-working surface alignment magnet , and the magnetic material is a Sm-Co-based, Nd-Fe-B-based, Sm-Fe-N. It can be one of the systems .

  Furthermore, according to the method of manufacturing a bonded magnet according to another aspect of the present invention, a flat bond having a first non-operating surface and a first operating surface in contact with the first non-operating surface via a joint portion is provided. A method of manufacturing a magnet, comprising the steps of preparing a cavity of a molding die filled with a bonded magnet composition containing a magnetic material and a resin, filling the molten bond magnet composition in the cavity, and applying a magnetic field. And orienting the magnetic material to form a bonded magnet, wherein the magnetic field comprises first and second magnetic fields applied so that the same poles face each other, The cavity is biased toward the first magnetic field side so as to be sandwiched between the first and second magnetic fields in the opposing direction of the magnetic field, and the length of the cavity in the opposing direction of the magnetic field is approximately same Distance spaced possible to the state in which the second magnetic field is formed.

  Furthermore, according to the method of manufacturing a bonded magnet according to another aspect of the present invention, a flat bond having a first non-operating surface and a first operating surface in contact with the first non-operating surface via a joint portion is provided. What is claimed is: 1. A method of manufacturing a magnet, comprising the steps of: providing a cavity of a molding die filled with a bonded magnet composition containing a magnetic material and a resin; and filling the molten bond magnet composition in the cavity; And a step of forming a bonded magnet by applying a magnetic field with an alignment magnet for magnetically aligning the magnetic material, the magnetic material being oriented so as to be oriented to form a bonded magnet. The magnet is configured to have first and second orientation magnets arranged such that the same poles face each other, and the cavity is formed by the first and second cavities in the axial direction of the orientation magnet. Between orientation magnets The second orientation magnet is disposed on the side of the first orientation magnet so as to be sandwiched, and at substantially the same distance as the length of the cavity in the axial direction of the orientation magnet. It can be done.

FIG. 1 is a schematic cross-sectional view showing a bonded magnet according to a first embodiment. It is a disassembled perspective view of the bond magnet of FIG. It is a schematic cross section which shows the group of the bond magnet piece which comprises the bond magnet of FIG. It is a schematic cross section which shows the cavity which shape | molds the bonded magnet piece of FIG. 3, and the magnet for orientation. 5A to 5F are schematic cross-sectional views showing a magnetic circuit device using a permanent magnet at the time of manufacturing a bonded magnet piece according to an embodiment. It is sectional drawing which shows each part of a bond magnet piece. FIGS. 7A to 7F are image diagrams showing the distribution of the magnetic flux density in each arrangement example of FIGS. 5A to 5F. FIGS. 8A to 8F are enlarged views of a part of the bonded magnet pieces in FIGS. 7A to 7F. 9A to 9F are image diagrams showing magnetic paths in the arrangement examples of FIGS. 5A to 5F. 10A to 10F are enlarged views of a part of the bonded magnet piece in FIGS. 9A to 9F. 11A to 11F are schematic cross-sectional views showing a magnetic circuit device using an electromagnet at the time of manufacturing a bonded magnet piece according to a comparative example. 12A to 12F are image diagrams showing the distribution of magnetic flux density in each arrangement example of FIGS. 11A to 11F. 13A to 13F are enlarged views of a part of the bonded magnet piece in FIGS. 12A to 12F. 14A to 14F are image diagrams showing magnetic paths in the respective arrangement examples of FIGS. 11A to 11F. FIGS. 15A to 15F are enlarged views of a part of the bonded magnet pieces in FIGS. 9A to 9F. It is a schematic cross section which shows the magnetic circuit apparatus using the permanent magnet at the time of bond magnet piece manufacture which concerns on a modification. It is sectional drawing which shows each part of a bond magnet piece and an orientation magnet. 18A: angle θ ₂ = 36 °, FIG. 18B: 30 °, FIG. 18C: 24 °, FIG. 18D: 18 °, FIG. 18E: 12 °, FIG. It is a graph which shows the result of having measured the orientation magnetic field for every position. FIG. 19A is a plan view showing a 12-pole cylindrical bonded magnet, FIG. 19B is a plan view showing a 10-pole cylindrical bonded magnet, FIG. 19C is a plan view showing an 8-pole cylindrical bonded magnet, and FIG. 19D is a 6-pole cylindrical bond It is a top view which shows a magnet. FIG. 20A is a graph showing the relationship between area ratio and surface magnetic flux density peak value in a bonded magnet segment having a central angle of 30 °, and FIG. 20B shows the relationship between area ratio and surface magnetic flux density peak value in a bonded magnet segment having a central angle of 36 ° FIG. 20C is a graph showing the relationship between the area ratio and the surface magnetic flux density peak value in a bonded magnet segment having a central angle of 45 °, and FIG. 20D is the relationship between the area ratio and the surface magnetic flux density peak value in a bonded magnet segment having a central angle of 60 ° Is a graph showing FIG. 21A is a graph showing the relationship between area ratio and magnetic flux in a bonded magnet segment having a central angle of 30 °, FIG. 21B is a graph showing the relationship between area ratio and magnetic flux in a bonded magnet segment having a central angle of 36 °, and FIG. FIG. 21D is a graph showing the relationship between the area ratio and the magnetic flux in the bonded magnet segment having a central angle of 60 ° in the bonded magnet segment having an angle of °. 22A is a graph showing the relationship between area ratio and magnetic flux in a bonded magnet segment having a central angle of 6 °, FIG. 22B is a graph showing the relationship between area ratio and magnetic flux in a bonded magnet segment having a central angle of 9 °, and FIG. 22D is a graph showing the relationship between area ratio and magnetic flux in a bonded magnet segment of °, FIG. 22D is a graph showing the relationship between area ratio and magnetic flux in a bonded magnet fragment having a central angle of 18 °, and FIG. FIG. 22F is a graph showing the relationship between the area ratio and the magnetic flux in a bonded magnet piece having a center angle of 22.5 °. It is a graph which shows the number of magnetic poles in the lower limit value of the area ratio used as high magnetic flux in Drawing 21A-Drawing 21D, and the relation of area ratio. It is a graph which shows the number of magnetic poles in the upper limit value of the area ratio used as high magnetic flux in Drawing 21A-Drawing 21D, and the relation of area ratio. It is a graph which shows the number of magnetic poles in the lower limit value of the area ratio used as high magnetic flux in Drawing 22A-Drawing 22F, and the relation of area ratio. It is a schematic diagram which shows the state of the orientation which used the permanent magnet. It is a schematic diagram which shows the state of the conventional pole orientation which used the permanent magnet. It is a graph which shows the surface magnetic flux density for every angle of the cylindrical bonded magnet comprised using the bond magnet piece of 30 degrees of center angles. It is the graph to which the part of 0 degree-72 degrees of the graph of FIG. 28 was expanded. It is a table | surface which shows the result of having measured the surface magnetic flux density of the magnet of Example 1 and Comparative Examples 1-3. FIG. 7 is a schematic cross-sectional view showing a bonded magnet according to a second embodiment. It is a schematic cross section which shows the bond magnet concerning a modification. It is a schematic cross section which shows the bond magnet which concerns on another modification. It is a schematic cross section which shows the bond magnet which concerns on another modification. It is a schematic cross section which shows the bond magnet which concerns on another modification. FIG. 7 is a schematic cross-sectional view showing a bonded magnet according to a third embodiment. FIG. 10 is a schematic cross-sectional view showing a bonded magnet according to a fourth embodiment. FIG. 21 is a schematic cross-sectional view showing a set of bonded magnet segments according to a fifth embodiment. It is a schematic cross section which shows the bond magnet which combined multiple sets of the bond magnet piece of FIG. It is a schematic cross section which shows the cavity which shape | molds the bonded magnet piece of FIG. 38, and the magnet for orientation. It is a schematic cross section which shows the group of the bond magnet piece which concerns on a modification. FIG. 21 is an exploded perspective view of a set of bonded magnet segments according to a sixth embodiment. FIG. 5 is a perspective view of a set of bonded magnet segments. It is sectional drawing which shows the orientation state of the magnetization easy axis of the magnetic powder particle in the VIC-VIC line cross section of FIG. It is sectional drawing which shows the magnetic force line of FIG. It is sectional drawing which shows the magnetic force line of the group of another bonded magnet piece. FIG. 18 is a view showing a magnetic circuit device at the time of production of a bonded magnet segment according to a sixth embodiment; FIG. 18 is a view showing a magnetic circuit device at the time of manufacturing a bonded magnet segment according to a sixth embodiment. It is a schematic cross section which shows the bonded magnet radially oriented as a magnetic orientation. It is a schematic cross section which shows the bonded magnet which carried out the convergence orientation. It is a schematic cross section which shows the state which has arrange | positioned the magnet for orientation in order to obtain the bonded magnet on which the convergence orientation of FIG. 50 was made to be carried out. It is a schematic cross section which shows the bonded magnet which made polar orientation. It is a schematic cross section which shows the state which has arrange | positioned the magnet for orientation in order to obtain the bonded magnet in which the polar orientation of FIG. 52 was made to be made. It is a schematic cross section which shows the state which forms the circular-arc-shaped magnetic field with the magnet for orientation so that polar orientation may be made. It is a schematic cross section which shows the state which tries to extend a magnetic path further from FIG. It is a graph which shows the BH line of a bond magnet.

  Hereinafter, embodiments of the present invention will be described based on the drawings. However, the embodiments shown below are exemplifications for embodying the technical idea of the present invention, and the present invention is not limited to the following. Further, the present specification does not in any way specify the members described in the claims to the members of the embodiment. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the embodiments are not intended to limit the scope of the present invention to the scope of the present invention unless otherwise specified. It is just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for the sake of clarity.

  According to the bond magnet according to another embodiment of the present invention, the area of the first surface is larger than the area of the second surface, and the area of the third surface is larger than the area of the fourth surface. It can be made wider.

  According to the bond magnet according to another embodiment of the present invention, the sum of the areas of the first surface and the fifth surface is larger than the area of the second surface, and the area of the third surface and the sixth surface Can be made wider than the area of the fourth surface.

  According to the bond magnet according to another embodiment of the present invention, the angle at which the first surface and the second surface intersect can be 90 ° or less.

  In the bonded magnet according to another embodiment of the present invention, the second bonded magnet piece has a flat outer shape, the flat main surface is the third surface, and the flat thickness direction In the inside of the second bonded magnet piece, magnetic lines of force can be bent symmetrically from the fourth surface to the third surface side.

  According to the bond magnet according to another embodiment of the present invention, the distribution of magnetic lines of force in each of the first bond magnet piece and the second bond magnet piece can be made substantially symmetrical. According to the above configuration, the magnetic pole faces are exposed to surfaces corresponding to the fan-shaped radius portions of the bond magnet pieces, and the magnetic pole faces are joined so as to have different poles each other, thereby forming a circular shape. Bond magnet can be configured.

  According to the bonded magnet in accordance with another embodiment of the present invention, the bonding surfaces of the first bonded magnet piece and the second bonded magnet piece can be bonded.

  According to the bond magnet according to another embodiment of the present invention, the second surface is a working surface, and the magnetic flux is not exposed to the outside from the surface of the first bond magnet piece opposite to the second surface. It can be configured. According to the above configuration, the magnetic lines of force are output only from one side to facilitate bonding of the bonded magnet pieces.

  According to the bond magnet according to another embodiment of the present invention, the joint portion between the first surface and the second surface, the joint portion between the first surface and the fifth surface, the third surface and the fourth surface And / or a joint portion between the third surface and the sixth surface may be linear.

  According to the bond magnet according to another embodiment of the present invention, the joint portion between the first surface and the second surface, the joint portion between the first surface and the fifth surface, the third surface and the fourth surface And / or a joint portion between the third surface and the sixth surface may be formed in a concave shape.

  Recently, in order to avoid the soaring price of sintered magnets against the background of resource problems and the difficulty of assembling method when using such sintered magnets, sintered magnets are used as permanent magnets for high torque motor rotors. It is conceivable to replace the bond magnet. In this case, it is conceivable to enhance the surface magnetic flux density by optimizing the magnetic orientation of the anisotropic material used as the magnet powder mixed in the bonded magnet, for example, SmFeN particles.

Conventionally, a radial orientation as shown in FIG. 49 is known as the magnetic orientation in the bonded magnet, but in this orientation, the magnetic path is short, so the magnetic flux density becomes weak. Therefore, as a method of improving the magnetic flux density, there are considered polar orientation in which magnetic orientation is performed so as to make the magnetic path longer, and convergent orientation in which the magnetic flux is converged to improve the magnetic flux density.
(Converging orientation)

As shown in FIG. 50, the convergent orientation is to increase the magnetic flux density of one magnetic pole (upper surface side in FIG. 50) by causing the magnetic flux to converge. In order to perform convergent orientation, as shown in the cross-sectional view of FIG. 51, the orientation magnet for forming the orientation magnetic field is different in size between the N pole and the S pole, and the bond is transferred. Increase the magnetic flux density on one working surface of the magnet molding. However, in this method, the distribution of the magnetic flux density can not be avoided due to the nature of forcibly generating the high magnetic flux density region, and for example, a high magnetic flux density region is obtained on the rotor surface for a motor. Not suitable for use.
(Polar orientation)

  On the other hand, in polar orientation, as shown in FIG. 52, lines of magnetic force from the N pole to the S pole of the orientation magnetic field are formed into a substantially arc shape to raise the demagnetizing curve operating point of the obtained bond magnet. For example, consider a manufacturing process in which a cylindrical bonded magnet used for a motor rotor is pole-oriented. Here, as shown in FIG. 53, a magnet for orientation is disposed around a cylindrical cavity which is a cavity of a molding die. As a result, as shown in the plan view of FIG. 54, an arc-shaped magnetic field is formed inside the cylinder, and the magnet particles are oriented along this magnetic field.

In this method, an orientation magnet is disposed on the outside of a cylindrical cavity corresponding to the surface of a cylindrical bonded magnet, and an external magnetic field is applied. As a result, as shown in FIG. 54, even when an orienting magnetic field is applied from the cylindrical cavity, the magnetic field produced inside the cylindrical cavity is in the form of a circular arc. Inside the resulting bond magnet, an arc-shaped magnetic path is formed in the vicinity of the working surface of the bond magnet. In this method, since the magnetic lines of force are formed in an arc shape, there is a problem that it can not be largely bent, and significant control of the orientation can not be performed. In other words, as shown in FIG. 55, if it is intended to penetrate the magnetic path deep into the inner surface of the bond magnet, it is not necessary to form a circular arc, but it is necessary to make the magnetic path bent largely in a U shape around the inside. Where it is, it has been physically difficult to form such a magnetic path from the surface of the cavity with an oriented magnet. That is, as shown in FIG. 56, in order to achieve the goal of increasing the operating point on the BH line, needs to be oriented to towards the center of the cylindrical bonded magnet to enter the magnetic field lines as shown in FIG. 55 In the configuration where the orientation magnetic field is applied from the outside of the cavity, there is a limit to the magnetic force of the orientation magnet. For example, when the diameter of the cylindrical bonded magnet is increased, the magnetic path may be penetrated to the inside There is a problem that it can not be made, and as a result, a strong magnetic force can not be generated.
Embodiment 1

  Therefore, in the bonded magnet according to the first embodiment of the present invention, the bonded magnet is divided, the bonded magnet pieces are separately formed, and then the obtained bonded magnet pieces are connected to form a bonded magnet. did. For example, in the case of forming a cylindrical bonded magnet having a substantially circular bottom surface, which is used for a motor rotor, as shown in the cross-sectional view of FIG. Furthermore, it divides | segments into the bonded magnet piece 10 of fan-shaped sectional view cut | disconnected by the cut surface (joining surface) which passes along a central axis. In the example of the bond magnet 100 shown in FIG. 1, as shown in the exploded perspective view of FIG. 2, eight external columnar bond magnet pieces 10 having substantially the same outer shape and 45 ° central angle of the sector on the bottom are combined. A cylindrical bonded magnet is obtained. Furthermore, magnetic lines of force of each bonded magnet piece 10 are generated along the magnetic path shown in FIG. 1, and as shown in the cross sectional view of FIG. The connecting faces are made to be non-working faces, and the magnetic poles are made to be different poles on the connecting faces of the adjacent bond magnet pieces 10 so that the magnetic flux lines are continuous.

In the example of FIG. 1, an example in which eight bonded magnet pieces 10 are combined to configure a cylindrical bonded magnet 100 has been described. In this case, on the circumferential side surface of the bond magnet 100, eight magnetic poles of S pole and N pole appear. The central angle θ ₀ of each bonded magnet piece 10 is 360 ° 3608 = 45 °. However, the present invention is not limited to this configuration, and the magnetic poles may be configured to appear in six or ten poles on the circumferential side. The central angles θ ₀ of the bonded magnet pieces 10 in this case are 60 ° and 36 °, respectively. Also, any number of magnetic poles or bonded magnet pieces can be employed.

  In the example of FIG. 1, the magnetic path group connected to the inside of the bond magnet from the action surface of the S pole and the N pole has a polar orientation bent so as to project in a parabolic shape toward the inside of the bond magnet. As described above, the magnetic path is not arc-shaped, but is bent in a parabolic shape or a quadratic curve shape, thereby projecting the parabolic magnetic path group from the side surface of the cylindrical bonded magnet toward the central axis of the cylinder It is possible to make the magnetic path longer. Further, the bonded magnet pieces divided by using the symmetry plane of this parabolic magnetic path group as a bonding surface are bonded at this bonding surface. Furthermore, the bonding surface of the bonded magnet pieces is a non-working surface, and the density of the easy magnetization axis in the working surface is higher than the density of the easy magnetization axis in the non-working surface. As a result, a bonded magnet is realized in which the surface magnetic flux density on the working surface is increased.

  In the present specification, parabolic does not mean strictly parabola but means an elliptic curve extended in a chevron in one direction. The oval shape is such that its long side is directed to the center of the sector. Further, “protruding toward the inside of the bond magnet” means that, as shown in FIG. 3, among the plurality of magnetic paths formed in a parabolic shape, the top AP of the longest magnetic path has a sector-shaped radius of 1 It means the state located in the center side rather than position HP of / 2.

The bonded magnet shown in FIG. 3 is composed of a first bonded magnet piece 10A and a second bonded magnet piece 10B. The first bonded magnet piece 10A is in contact with the first surface 11, a second surface 12 in contact with the first surface 11 via a joint portion, and the second surface 12 via a joint portion, and the first surface 11 And a fifth surface 15 in contact with the joint portion. In the first bonded magnet piece 10A, the first surface 11 and the fifth surface 15 are inclined at a constant central angle θ _o , and the first bonded magnet piece 10A is surrounded by the first surface 11, the fifth surface 15, and the second surface 12 The external shape in a cross sectional view is fan-shaped. Further, in the inside of the first bonded magnet piece 10A, the first magnetic field line group 21 is internally curved so as to be directed from the first surface 11 to the second surface 12. Similarly, the third magnetic field line group 23 is curved inside from the fifth surface 15 toward the second surface 12. The fifth surface 15 is a bonding surface at the time of bonding with another bonded magnet piece (not shown), specifically, another bonded magnet piece having the same orientation as the second bonded magnet piece 10B. At this time, the fifth surface 15 is a third non-operating surface.

Here, the sum of the physical areas of the first surface 11 and the fifth surface 15 of the first bonded magnet piece 10A is formed wider than the physical area of the second surface 12. In other words, when the height of the first bonded magnet piece 10A having a fan-shaped cross section is constant, the sum of the line segment OA ₃ corresponding to the first surface 11 and the line segment OA ₁ corresponding to the second surface 12 in FIG. Is longer than the arc A ₁ A ₃ . Thereby, the surface magnetic flux density of the second surface 12 can be made higher than the surface magnetic flux density appearing on the first surface 11 and the fifth surface 15. Preferably, the first surface 11 is wider than the second surface 12. In other words, the line segment OA ₃ and the corresponding first surface 11 in FIG. 3, is longer than the arc A ₁ A _3. Thereby, the surface magnetic flux density of the second surface 12 can be further increased.

More preferably, the first magnetic field lines 21 and the third magnetic field lines 23 are distributed substantially symmetrically with respect to a line bisecting the inclination angle θ ₀ of the first bonded magnet piece 10A having a fan shape in cross section (the line OA _{2 in} FIG. 3). Let In addition, the 1st surface 11 comprises the joint surface for joining with the 2nd bonded magnet piece 10B, and for this reason, it becomes a 1st non-working surface which does not appear outside. On the other hand, the second surface 12 acts as a magnetic pole exposed to the outside, and becomes a first action surface.

On the other hand, the second bonded magnet piece 10B is in contact with the third surface 13, the fourth surface 14 in contact with the third surface 13 via the junction, and the fourth surface 14 via the junction, and the third surface And a sixth surface 16 in contact with the joint portion. In the second bonded magnet piece 10B, the third surface 13 and the sixth surface 16 are inclined at a constant central angle θ ₀ , and are surrounded by the third surface 13, the sixth surface 16 and the fourth surface 14 The external shape in a cross sectional view is fan-shaped. In the inside of the second bonded magnet piece 10B, the second magnetic field line group 22 is internally curved so as to be directed from the fourth surface 14 to the third surface 13. Similarly, the fourth magnetic field line group 24 is internally curved from the fourth surface 14 toward the sixth surface 16. The sixth surface 16 is a bonding surface at the time of bonding with another bonded magnet piece (not shown), specifically, another bonded magnet piece having the same orientation as the first bonded magnet piece 10A. At this time, the sixth surface 16 is a fourth non-operating surface.

Here, the sum of the physical areas of the third surface 13 and the sixth surface 16 of the second bonded magnet piece 10B is formed wider than the physical area of the fourth surface 14. The sum of the other words, when the height of the second bond magnet piece 10B of the cross section fan is constant, the line segment OA ₅ corresponding to the line segment OA ₃ and the corresponding third surface 13 in FIG. 3 and 6 th 16 Is longer than the arc A ₃ A ₅ . Thereby, the surface magnetic flux density of the fourth surface 14 can be made higher than the surface magnetic flux density appearing on the third surface 13 and the sixth surface 16. Preferably, the third surface 13 is wider than the fourth surface 14. In other words, the line segment OA ₃ and the corresponding third surface 13 in FIG. 3, is longer than the arc A ₃ A _5. Thereby, the surface magnetic flux density of the fourth surface 14 can be further increased.

Preferably, the second magnetic field lines 22 and the fourth magnetic field lines 24 are distributed substantially symmetrically with respect to a line bisecting the inclination angle θ ₀ of the second bonded magnet piece 10B having a fan-shaped cross section (the line OA _{4 in} FIG. 3). Let The third surface 13 constitutes a bonding surface for bonding to the first bonded magnet piece 10A, and thus becomes a second non-working surface that is not exposed to the outside. On the other hand, the fourth surface 14 acts as a magnetic pole exposed to the outside, and becomes a second action surface.

  The magnetic pole of the first surface 11 of the first bonded magnet piece 10A and the magnetic pole of the third surface 13 of the second bonded magnet piece 10B have different polarities. In this example, by making the first surface 11 the S pole and the third surface 13 the N pole, the bonding surfaces can be bonded. Also, the bonding surface may be bonded. Then, the first surface 11 of the first bonded magnet piece 10A and the third surface 13 of the second bonded magnet piece 10B are connected so that the second magnetic force line group 22 and the first magnetic force line group 21 are continuous. Be done.

  In this way, the combination of the first bonded magnet pieces 10A and the second bonded magnet pieces 10B, the set of bonded magnet pieces obtained, that is, the bonded magnets, the side faces become the working surface. In the working surface, different magnetic poles are exposed to the outside by the second surface 12 of the first bonded magnet piece 10A and the fourth surface 14 of the second bonded magnet piece 10B. In the example of FIG. 3, the second surface 12 is an N pole, and the fourth surface 14 is an S pole. Thereby, while realizing pole orientation in which the magnetic path is bent inside, the magnetic flux of the first surface 11 of the first bonded magnet piece 10A and the magnetic flux of the fifth surface 15 are converged by the second surface 12, And, the magnetic flux of the third surface 13 of the second bonded magnet piece 10B and the magnetic flux of the sixth surface 16 are converged by the fourth surface 14 so that a high magnetic flux density can be realized on the working surface.

  In this manner, the magnetic pole faces are exposed so as to be different poles each other by exposing the magnetic pole faces to the face corresponding to the fan-shaped radius portion of each bond magnet piece, thereby forming a circular shape. Bond magnet can be configured.

  In the example of FIG. 3, the shapes of the first bonded magnet piece 10A and the second bonded magnet piece 10B are the same. However, the present invention is not limited to this configuration, and the shapes of the first bonded magnet piece and the second bonded magnet piece may be made different.

  By dividing and forming the bond magnet in this way, as shown in FIG. 4, the part which becomes the center side at the time of the configuration of the cylindrical bond magnet at the time of forming the bond magnet pieces, that is, It becomes possible to arrange the orientation magnet, and as a result, it becomes possible to orient so as to make the lines of magnetic force enter near the center of the cylindrical bonded magnet. Thereby, as shown in the cross-sectional view of FIG. 1, it is possible to realize the orientation in which the magnetic path is extended in the direction near the center, which was conventionally difficult when assembled in the cylindrical bonded magnet 100. The surface magnetic flux density on the working surface can be improved by extending the magnetic path. In addition to the effect of surface magnetic flux density improvement in pole orientation by extending the magnetic path in this way, according to the above configuration, the working surface is a noncircular arc-shaped portion in a sectional view, as shown in FIG. Since the magnetic flux density can be increased by narrowing the area of the working surface smaller than the working surface and concentrating the magnetic flux here, in addition to the polar orientation, a convergent orientation can be realized, and a higher magnetic flux density can be obtained.

In other words, in addition to the pole orientation in which the magnetic flux is bent in a U-shape in the bond magnet, the magnetic pole on the non-working surface is wider than the magnetic pole on the working surface. A state in which the magnetic flux is constricted is created, and a convergent orientation with high surface magnetic flux density is realized at the working surface.
(Method of manufacturing bonded magnet)

  Next, an apparatus and a method for manufacturing the bond magnet 100 will be described with reference to FIG. Although the example of FIG. 4 shows a method of manufacturing the first bonded magnet piece 10A, the second bonded magnet piece 10B can be formed by replacing the magnetic poles of the orientation magnet.

  Here, the magnetic flux density on the working surface is increased by performing convergent orientation on the bonded magnet pieces, making the wide pole surface the non-working surface, and making the narrow pole surface the working surface. In order to realize this, orientation magnets are disposed in the portions corresponding to the working surface and the non-working surface of the cavity of the molding die. In the example of FIG. 4, in order to obtain the first bonded magnet, the magnet 62 for orienting the first working surface is disposed on the first working surface 12, and the magnet 61 for orienting the first nonworking surface is arranged on the first nonworking surface 11. Deploy. Here, the convergent orientation can be realized by making the area of the non-action surface larger than the area of the action surface. Further, the third non-working surface alignment magnet 65 is disposed on the third non-working surface 15. The first non-working surface alignment magnet 61 and the third non-working surface alignment magnet 65 have the same magnetic pole (N pole in the example of FIG. 4) to repel the magnetic field in the cavity, and the magnetic field lines It is possible to perform orientation toward the working surface orientation magnet 62 (S pole in the example of FIG. 4), and a stronger convergent orientation can be realized.

Furthermore, the degree of convergent orientation can also be adjusted by adjusting the area ratio of the magnetized areas of the non-working surface and the working surface. Specifically, the area of the first working surface alignment magnet 62 disposed on the first working surface and the area of the first non-working surface alignment magnet 61 disposed on the first non-working surface are set to the required specifications. Design according to. For example, the area ratio can be adjusted according to the maximum surface magnetic flux density, the distribution of the magnetic flux density, and the like as specifications required for a rotor for a motor or the like, and a bonded magnet with an optimal specification can be obtained. The area ratio is the ratio A / B of the area of the area of length A corresponding to the radius and the area of the area of the magnetized part B of the part corresponding to the arc of the fan shape of the bonded magnet piece. When the cylindrical height of the bonded magnet piece is constant, the area ratio A / B can also be expressed as a ratio of length A / B.
(Magnet for orientation)

  A permanent magnet is used for the orientation magnet used at the time of shaping | molding of the bonded magnet piece shown in FIG. The material of such a permanent magnet preferably has a Br of 1 T or more, and for example, an Nd-Fe-B sintered magnet can be used. When a magnet having a large magnetic force is used, the orienting magnetic field becomes strong, and the surface magnetic flux density of the bond magnet can also be increased.

The mold is filled with the bonded magnet composition that constitutes the bonded magnet. Injection molding or compression molding can be used for molding. The bonded magnet composition also contains at least a magnetic material and a resin.
(Magnetic material)

  An anisotropic material is employed as the magnetic material. Examples of anisotropic magnetic materials include ferrites, Sm-Cos, Nd-Fe-Bs, Sm-Fe-Ns, and the like. It is a material from which predetermined magnetic performance can be obtained by anisotropy, BHmax is large compared to isotropic materials, and effective magnetic flux density can be provided in the air gap even when used as a field unit.

Ferrite type is most popular because of its long history and low cost, but the magnetic force is weaker than the rare earth type, and if the molded product becomes smaller, the magnetic force will be insufficient. It is preferable to use Sm-Co based, Nd-Fe-B based, and Sm-Fe-N based rare earth based magnetic powders. The above magnetic materials may be used alone or in combination of two or more. Moreover, you may perform an oxidation resistance process and a coupling process as needed.
(resin)

  The resin used in this embodiment is not particularly limited, and examples thereof include thermoplastic resins such as polypropylene, polyethylene, polyvinyl chloride, polyester, polyamide, polycarbonate, polyphenylene sulfide and acrylic resin, esters, and polyamides. Thermoplastic elastomers or thermosetting resins such as epoxy resin, phenol resin, unsaturated polyester resin, urea resin, melamine resin, polyimide resin, allyl resin, silicone resin and the like can be used.

  The first working surface alignment magnet 62, the first non-working surface alignment magnet 61, and the third non-working surface alignment magnet 65 shown in FIG. Magnetic line groups are generated. The magnetization easy axis of the magnetic powder particle before resin curing is oriented by the group of magnetic force lines generated by the alignment magnet, and then the resin is cured to form two magnetic path groups having paths substantially corresponding to the respective magnetic field lines. A bonded magnet 10A is formed to be formed. In addition, bond magnets 10B are created in which two magnetic path groups having paths substantially corresponding to the second magnetic field line group 22 and the fourth magnetic field line group 24 are similarly generated by reversing the polarities of the alignment magnets, respectively.

The bond magnet 100 shown in FIG. 1 is produced by arranging the non-working surface in contact so that the bond magnet pieces 10A and the bond magnet pieces 10B alternately align the arc side. In the bond magnet 100, as shown in FIG. 1, magnetic paths extending from the non-action surface inside each bond magnet piece are bent in a parabolic shape and focused on the action surface. Magnetic paths extending from the non-operating surface are connected to each other at the non-operating surface where the adjacent bonded magnet pieces 10A and 10B are in contact, and a parabolic magnetic path group projecting inward from the operating surface is formed. 1 is recaptured by the assembly of two bonded magnet pieces shown in FIG. 3, and the magnetic path groups of the second bonded magnet piece 10B connected to one magnetic path group of the first bonded magnet piece 10A are combined to obtain the first magnetic The divided surface or joint surface divided into the first bonded magnet piece 10A and the second bonded magnet piece 10B as a path group is a first joint surface which is a symmetry plane of the first magnetic path group. In addition, the magnetic path group of the second bonded magnet piece 10B connected to another magnetic path group of the first bonded magnet piece 10A is combined to form a second magnetic path group, and a second joint surface which is a symmetry plane of the second magnetic path group It becomes. Thus, each bonded magnet piece is divided at the first bonding surface and the second bonding surface. The first bonding surface and the second bonding surface intersect at a central axis of the cylindrical shape.
(Comparative test 1)

Here, the simulation results of the magnetic flux density obtained by each bonded magnet in the case of using the orientation magnetic circuit device using the permanent magnet and the electromagnet as one of the manufacturing apparatus used for manufacturing the bonded magnet or the bonded magnet piece are shown. As shown in FIGS. 5A-5F. In these figures, the first non-working surface alignment magnet 61, the first working surface alignment magnet 62, and the third non-working surface alignment magnet 65 as shown in FIG. 5A are magnetically connected to each other to form a magnetic circuit. And a cavity of a molding die for filling the bonded magnet composition forming the bonded magnet. Here, the area WD of the first non-acting surface 11 of the first non-working surface alignment magnet 61 (cylindrical radius) and the central angle θ _{0 of the} sector shape are fixed, and the width WD of the first working surface alignment magnet 62 Changed. Here, as shown in FIG. 6, the width WD of the first working surface alignment magnet 62 is equivalent to the length of an arc where the end face of the first working surface alignment magnet 62 contacts the first working surface 12 of the bonded magnet piece. It is represented by an angle theta ₂ to. In this example, the cylindrical radius A = 20 mm, the sector central angle θ ₀ = 36 °, and the angle θ ₂ of the first working surface alignment magnet 62 is 36 °, 30 °, 24 °, in 6 ° increments. The angle was changed to 18 °, 12 °, 6 °. The arrangement example of each orientation magnet is shown in FIGS. 5A to 5F. Furthermore, the distribution of the magnetic flux density in each arrangement example is respectively shown in FIGS. 7A to 7F. Moreover, the figure which expanded the part (lower half) of the bond magnet piece in each figure is each shown to FIG. 8A-FIG. 8F. Furthermore, the result which showed the magnetic path is shown in FIGS. 9A-9F, and the figure which expanded the part (lower half) of the bond magnet piece in each figure is respectively shown in FIGS. 10A-10F.

On the other hand, as a comparative example, an example using an electromagnet instead of a permanent magnet as an orientation magnet is shown in FIGS. 11A to 11F. Here, as in the above-described FIGS. 5A to 5F, the electromagnet 61 ′ for first non-working surface alignment, the electromagnet 62 ′ for first working surface alignment, the electromagnet 65 ′ for third non-working surface alignment, and these are magnetically The yoke 66 'constituting the magnetic circuit was connected to form a cavity of a molding die for filling the bond magnet composition constituting the bond magnet. Further, the area of the first non-operating surface 11 of the first non-operating surface alignment electromagnet 61 'and the central angle θ _{0 of the} fan shape are fixed, and the width WD of the first active surface alignment electromagnet 62' is set to the angle θ ₂ By changing as shown in FIG. 11A to FIG. 11F. The distribution of the magnetic flux density obtained by this is shown in FIGS. 12A to 12F, respectively. Moreover, the figure which expanded the part (lower half) of the bond magnet piece in each figure is similarly respectively shown to FIG. 13A-FIG. 13F. Furthermore, the result which showed the magnetic path in FIG. 14A-FIG. 14F, and the figure which expanded the part (lower half) of the bond magnet piece in each figure is respectively shown in FIG. 15A-FIG.

  In the examples of FIGS. 5A to 5F and FIGS. 11A to 11F, only the first bond magnet piece is formed while forming a cavity capable of forming two of the first bond magnet piece and the second bond magnet piece in the mold. In order to form, the space which a 2nd bonded magnet piece occupies is filled with nonmagnetic steel (for example, stainless steel etc.). In order to show this, a cavity corresponding to the outer shape of the first bonded magnet piece is shown in each of the drawings. However, the present invention is not limited to this configuration, and two of the first bonded magnet piece and the second bonded magnet piece can be simultaneously formed. Such an example is shown in FIG.

  As described above, the permanent magnet and the electromagnet are used as orientation magnets, and each position ratio of the bonded magnet pieces obtained respectively in each position in the radial direction (0 mm to 20 mm from the center side in A = 20 mm in FIG. 17 The results of measuring the orientation magnetic field [T] at each position of (1) are shown in FIGS. 18A to 18F, respectively. Here, as shown in FIG. 17, the area ratio is the ratio A of the area formed by the portion of the cylindrical radius A of the bonded magnet piece to the length B from the upper end to the area magnetized from the upper end of the arc portion. It is / B. The ratio of A / B is equal to the area ratio when the cylindrical heights of the bonded magnet pieces are the same, so in the following, A / B may be referred to as the area ratio.

In FIG. 17, in a bond magnet segment in a fan shape in plan view, a first magnetic field line group which is internally curved from the first surface to the second surface so as to be substantially line symmetrical (above and below the horizontal line passing the center in FIG. 17); And a third group of magnetic field lines, which are internally curved from the fifth surface to the second surface, are oriented. Therefore, among the magnetized regions of the second surface, the region B corresponding to the first magnetic field line group and the region B ′ corresponding to the third magnetic field line group can be considered to be substantially equal, so The degree of focusing of the magnetized region is determined by the region B corresponding to the magnetic field lines of. The larger the value of the area ratio A / B, the more the magnetic flux is focused. In each figure, FIG. 18A corresponds to the angle θ ₂ = 36 °, and the area ratio is 3.18. FIG. 18B corresponds to the angle θ ₂ = 30 °, and the area ratio is 3.82. FIG. 18C corresponds to the angle θ ₂ = 24 °, and the area ratio is 4.77. FIG. 18D corresponds to the angle θ ₂ = 18 °, and the area ratio is 6.37. FIG. 18E corresponds to the angle θ ₂ = 12 °, and the area ratio is 9.55. FIG. 18F corresponds to the angle θ ₂ = 6 ° and the area ratio is 19.10. As apparent from these figures, the electromagnet exhibits a high oriented magnetic field only on the side close to the arc, because the magnetic flux is short-cut from yoke to yoke. In other words, a pattern of magnetic paths close to the radius of curvature, which can be oriented only in the vicinity of the working surface and the magnetic flux becomes weaker toward the center of the cylindrical shape, that is, the magnetic path can not extend parabolically toward the center Show that This situation can also be confirmed from FIGS. 15A to 15F.

  In the case of a bonded magnet piece using one permanent magnet, since it is easy to orient in the entire cavity, the orientation magnetic field tends to become stronger as it goes to the working surface with good linearity, and a certain amount of orientation near the cylindrical center The indication of the magnetic field, in other words, the fact that the magnetic path has reached the cylindrical central portion. This situation can also be confirmed from FIGS. 10A to 10F showing the orienting magnetic field. Therefore, it can be confirmed that the permanent magnet is superior to the electromagnet for the orientation magnet.

In particular, the orientation method using a permanent magnet is suitable for orientation of a bonded magnet using a rare earth such as Sm. For example, in a bonded magnet using ferrite as shown in Patent Document 4, the orientation can be controlled even with a weak orientation magnetic field, but in the case of a rare earth bonded magnet, a strong orientation magnetic field is required, as in Patent Document 4. In the method, it is difficult to orient to the inside of a cylindrical shape, and as shown in FIGS. 15A to 15F, the orientation along the radius of curvature can be obtained only near the surface of the working surface. On the other hand, if it is a method of molding a bonded magnet into individual pieces of bonded magnet pieces using the permanent magnet according to the embodiment described above, the control of the orientation pattern oriented up to the cylindrical back region is realizable.
(Change of the number of magnetic poles)

Next, the width of the orienting magnet, that is, the area of the magnetized region in the bonded magnet piece is considered. In the above-described example, when the central angle of the sector of the bond magnet piece is 36 °, and a plurality of identical bond magnet pieces are combined to form a cylindrical bond magnet, as shown in the plan view of FIG. The configuration in which ten magnetic poles are provided along the circumference with the magnet piece has been described. Here, the peak of the surface magnetic flux density when the area ratio A / B of the magnetized area is changed for each of the bonded magnet pieces whose central angles are changed not only 36 ° but also 30 ° to 60 °. The values [T] are shown in FIGS. 20A to 20D, respectively. 21A to 21D show graphs in which the average magnetic flux density is multiplied by the area to obtain the magnetic flux [Wb]. In each figure, FIG. 20A, FIG. 21A can construct a cylindrical bond magnet having 12 magnetic poles as shown in FIG. 19A, with the center angle θ ₀ of the bond magnet piece set to 30 ° (π / 6 [rad]). The surface magnetic flux density and magnetic flux at the time of changing area ratio A / B of the bonded magnet piece are shown. Similarly, FIG. 20B, FIG. 21B is a central angle _{θ 0 36 ° (π / 5} [rad], magnetic poles 10 as shown in FIG. 19B), FIG. 20C, FIG. 21C is a central angle θ ₀ 45 ° ( In FIGS. 20D and 21D, the central angle θ ₀ is 60 ° (π / 3 [rad], as shown in FIG. 19D, the number of magnetic poles is 6). The surface magnetic flux density and magnetic flux in the case of each setting are shown in FIG. Furthermore, above it showed the relationship between the area ratio A / B and the magnetic flux of the bond magnet pieces obtained by changing the center angle theta ₀ to 30 ° to 60 °, to further reduce the center angle theta _0, increasing the number of magnetic poles It can also be done. Here, the relationship between the area ratio A / B of each bonded magnet piece and the magnetic flux when the number of magnetic poles is changed from 16 poles to 60 poles is shown in the graphs of FIGS. 22A to 22F. In these figures, FIG. 22A shows a central angle θ ₀ of 6 ° (pole number 60), FIG. 22B shows a central angle θ ₀ of 9 ° (pole number 40), and FIG. 22C shows a central angle θ ₀ of 12 ° (pole number 22D, the central angle θ ₀ is 18 ° (20 poles), FIG. 22E is the central angle θ ₀ 20 ° (18 poles), and FIG. 22F is the central angle θ ₀ 22.5 ° (poles) 16).

As shown in these figures, the surface magnetic flux density tends to increase as the area ratio A / B increases, that is, as the width WD of the first working surface alignment magnet 62 decreases. On the other hand, the magnetic flux shows a peak value in a low area ratio A / B area, for example, when the central angle is 30 °, the area ratio A / B is 5-8, and when it is 36 °, 4-7, 45 ° In the case of 3-4, 60 ° showed a high value in the range of 2-3. From the above results, it can be said that the area ratio A / B is preferably in the range of 2.0 to 8.0 when the central angle θ ₀ is in the range of 30 ° to 60 °.

Thus, it was confirmed that the magnetic flux becomes higher in the range where the area ratio A / B is smaller as the central angle of the fan-shape becomes larger. Here, the range of preferable area ratio A / B is examined. First, in order to confirm the lower limit value of the area ratio A / B when the number n of magnetic poles is 12 or less, in FIGS. 21A to 21D, the minimum value which is the lower limit of the area ratio A / B is plotted for each number of magnetic poles. A graph approximated by a straight line is shown in FIG. Also, in order to confirm the upper limit value of the area ratio A / B, in FIGS. 21A to 21D, the limit value to achieve the magnetic flux at the lower limit value of the area ratio A / B is plotted for each number of magnetic poles and approximated by a quadratic curve The resulting graph is shown in FIG. Similarly, in order to confirm the lower limit value of the area ratio A / B when the number n of magnetic poles is larger than 12, in FIGS. 22A to 22D, the minimum value that is the lower limit of the area ratio A / B is plotted for each number of magnetic poles. A graph approximated by straight lines is shown in FIG. As a result, when the number of magnetic poles n is 12 or less (θ ₀ 30 30), the area ratio A / B is in the range of 0.3184 n ≦ (A / B) <− 0.04 n ³ +1.47 n ² −14.03 n + 43 It is preferable to do. When the number of magnetic poles n is larger than 12, the area ratio A / B of (θ ₀ <30) is preferably in the range of 0.3184 n ≦ (A / B).
(Alignment rate)

  The orientation ratio measured by the orientation using the permanent magnet according to the embodiment of the present invention and the conventional polar orientation using the permanent magnet shown in FIG. 54 is shown in FIG. 26 and FIG. Here, for measurement of the orientation rate, first, the sample is sliced to a thickness of 1 mm to 2 mm, further cut into 1 mm square cut pieces, and the weight is measured. Next, the orientation direction is measured for each cut piece by VSM. The orientation direction obtained for each cut piece is shown in FIG. 26 and FIG. Furthermore, magnetization is performed in the obtained orientation direction, and the magnetization of the sample after magnetization is further measured by VSM. Then, with the magnetization of the magnetic powder used for the sample as 100%, the orientation ratio of each sample is calculated.

In the conventional polar orientation, as shown in FIG. 27, the central portion was not oriented, and the average orientation rate was 62.5%. On the other hand, in the orientation using a permanent magnet, as shown in FIG. 26, the orientation is achieved up to the central portion, and an average orientation rate of 85% is achieved. This state can also be confirmed from the graphs of FIGS. 18A to 18F in which the orienting magnetic field is measured at each position in the radial direction with respect to each area ratio described above. In the central portion (regions with a radius of 0 to 4 or 0 to 5 in the graphs of FIGS. 18A to 18F), the reverse orientation is shown. This is because the strength of the orienting magnetic field is measured as an absolute value, and a shortcut is generated in the orienting magnet to form the reverse orientation. For example, when using for a motor etc., this part is deleted and used. In particular, since the central part of the motor inserts the rotary shaft, it is not a problem to delete the central part, but it is preferable.
(Surface flux)

In order to confirm the degree of convergence of the magnetic flux from the obtained bonded magnet, the surface magnetic flux is measured. For example, a cylindrical bonded magnet configured using a cylindrical bond magnet configured using a bonded magnet piece created at a 30 ° pitch shown in FIG. 5B and a bonded magnet piece created at a 6 ° pitch shown in FIG. 5F The surface magnetic flux density [T] along the circumferential direction (0 ° to 360 °) is shown in FIG. As shown in FIG. 29, which is an enlarged view of this part, when the width WD of the orientation magnet is narrowed, the magnetic flux is more concentrated, the surface magnetic flux density is also increased, and a sharp profile is shown. On the other hand, when the width WD of the orientation magnet is relatively increased, the peak value of the surface magnetic flux density is lowered, but it exhibits a gentle rise and fall profile. Thus, the pitch of the bonded magnet pieces can be estimated from the profile waveform of the surface magnetic flux density.
(Comparative test 2)

  Next, simulation test results of computing surface densities of bonded magnets and sintered magnets of various embodiments when applied to a round rod (cylindrical or cylindrical) permanent magnet used for a rotor or the like of a motor as Comparative Test 2 Is shown in FIG. Here, a conventional sintered magnet (Sample 1) as Comparative Example 1, a bonded magnet with radial orientation (Sample 2) as Comparative Example 2, a pole-oriented bonded magnet (Sample 3) as Comparative Example 3, and Example 1 The surface magnetic flux density in the case of trial manufacture using the cylindrical bonded magnet (sample 4) according to the first embodiment was calculated. Here, NdFeB is used as a magnetic substance as magnetic powder of a sintered magnet or a bonded magnet. As shown to this figure, the surface magnetic flux density of samples 1-4 became 4000 G, 2000 G, 3000 G, and 4000 G, respectively. As described above, according to the first embodiment, the surface magnetic flux density equivalent to that of the sintered magnet which is considered to be the strongest in the past is realized by the bond magnet, and while using the bond magnet, the sintered magnet It was confirmed that the extremely high magnetic flux density of the same level can be achieved. In addition, even with the use of neodymium, which has been regarded as the most powerful magnetic material in the past, even magnetic materials using samarium can exhibit sufficient magnetic flux density, and also in terms of effective use of limited natural resources and reduction of country risk. It will be a highly practical technology.

In addition, when used as a rotor of a motor in this way, it can be used in a state of being integrated as a cylindrical bonded magnet without sticking a permanent magnet to the surface of the rotor as in the conventional SPM.
Second Embodiment

  Although the example which comprises a cylindrical bonded magnet was demonstrated in the above example, this invention is applicable not only to a cylindrical shape but to the bond magnet of another form. For example, the cylindrical bonded magnet 200 according to the second embodiment shown in the cross sectional view of FIG. 31 can also be used. Also in this case, each bonded magnet piece can be manufactured by the same manufacturing method as that of the first embodiment. In particular, if sufficient magnetic flux density can be obtained without extending the magnetic path to the cylindrical central portion, this configuration can reduce the amount of use of the bonded magnet composition such as the magnetic material and resin required, and the weight It also contributes to weight reduction.

Further, in the example of FIG. 1 etc., the joint portion between the first surface 11 and the second surface 12, the joint portion between the first surface 11 and the fifth surface 15, the joint portion between the third surface 13 and the fourth surface 14, The joint portion between the third surface 13 and the sixth surface 16 is linear. On the other hand, in the example of the cylindrical bond magnet 200 of FIG. 31, the joint portion between the first surface 11 and the second surface 12, the joint portion between the second surface 12 and the fifth surface 15, the third surface 13 and the fourth The joint portion with the face 14 and the joint portion with the fourth face 14 and the sixth face 16 are all linear, while the joint portion between the first face 11 and the fifth face 15 and the third face 13 with the fifth The junction with the six surfaces 16 is a concave curved surface.
(Modification)

  In the above example, the central axis of the cylindrical bond magnet is hollowed out in a cylindrical shape, but the cross-sectional shape hollowed out of the central axis is not limited to a circle, but any shape can be used. For example, as shown in the cross-sectional view of FIG. 32, the cross section may be star-shaped. By making the protruding portions forming the star shape enter between the parabola of each magnetic path group, while reducing the influence on the magnetic path, the volume and weight of the bonded magnet, and the usage amount of the bonded magnet composition Can be reduced. In this case, the joint portion between the first surface 11 and the second surface 12, the joint portion between the second surface 12 and the fifth surface 15, the joint portion between the third surface 13 and the fourth surface 14, the fourth surface 14 The joint portion with the sixth surface 16 is made linear, while the joint portion with the first surface 11 and the fifth surface 15 and the joint portion with the third surface 13 and the sixth surface 16 are cross-sectional views V It has two flat planes inclined in a letter shape.

Also, as shown in the cross-sectional view of FIG. 33, the cross-sectional shape is such that a semicircle or an ellipse having a small radius is additionally formed at regular intervals and a track shape is protruded, or as shown in the cross-sectional view of FIG. The cross-sectional shape may be tapered so as to project along the parabolic curve of the magnetic path, or alternatively, as shown in the cross-sectional view of FIG. Thus, any cross-sectional shape that does not disturb the magnetic path as much as possible can be adopted as appropriate. In any case, the joint between the first surface 11 and the second surface 12, the joint between the second surface 12 and the fifth surface 15, the joint between the third surface 13 and the fourth surface 14, the fourth surface While making the junction between 14 and the sixth surface 16 linear, make the junction between the first surface 11 and the fifth surface 15 and the junction between the third surface 13 and the sixth surface 16 inclined. The corresponding area is partially cut out from the triangular prism obtained by joining the two faces in a straight line.
Third Embodiment

Furthermore, in the second embodiment described above, although a configuration has been described in which cutting is performed on the central axis side of a cylinder among non-acting surfaces that are the interfaces for bonding adjacent bonded magnet pieces, the present invention is not limited to this configuration. Conversely, it may be configured to cut off on the working surface side, that is, on the circular arc side of the cylinder. Such an example is shown as Embodiment 3 in FIG. In the bond magnet 300 shown in this figure, of the cylindrical side surfaces, the bonding interface between the bond magnet pieces is recessed in a concave shape. In this example, the recesses are formed in a slit-like manner at regular intervals, that is, intervals corresponding to the length of the arc of each bond magnet piece, along the columnar height or longitudinal direction. In particular, when cylindrical bonded magnets are used for the rotor of a motor, permanent magnets are not arranged all around circumferentially, but are arranged at regular intervals as in the third embodiment. Bond magnet 300 is adapted to such a configuration. In addition, it contributes to reduction of raw material cost and weight reduction by volume reduction of bonded magnet.
In this case, the joint portion between the first face 11 and the fifth face 15 and the joint portion between the third face 13 and the sixth face 16 are all linear, while the first face 11 and the second face The joint portion with 12, the joint portion with the second surface 12 and the fifth surface 15, the joint portion with the third surface 13 and the fourth surface 14, and the joint portion with the fourth surface 14 and the sixth surface 16 are concave As a curved surface.
Embodiment 4

  In addition, in the second and third embodiments described above, an example has been described in which one corner portion of the non-working surface which is an interface for bonding adjacent bonded magnet pieces is deleted, but the present invention is limited to this configuration. Alternatively, both may be deleted. Such an example is shown in the cross-sectional view of FIG. 37 as a bonded magnet 400 according to the fourth embodiment. Even with this configuration, the effects such as the improvement of the magnetic flux density on the working surface, the weight reduction, and the cost reduction can be obtained.

As mentioned above, the structure which cuts a part of non-working surface can be used suitably. In addition, the non-working surface is not limited to a planar configuration, and a configuration such as, for example, a gently curved surface or partial provision of irregularities may be employed as appropriate. In particular, the configuration in which the concave shape and the convex shape are joined also plays a role of positioning at the time of engagement of the bond magnet pieces, which also leads to improvement in workability at the time of assembly.
Fifth Embodiment

  Furthermore, although the example which made the end surface of each bond magnet piece fan-shaped was demonstrated in the above example, the end surface shape of a bond magnet piece is not limited to a fan shape, and can also be made into another shape. For example, in the set of bonded magnet segments shown in FIG. 38 as the fifth embodiment, the seventh surface 517 and the eighth surface connect the first surface 511 and the second surface 512 in the cross-sectional view with the first bonded magnet segment 510A. Having 518. The first bonded magnet piece 510A has a tapered cross-sectional shape that is surrounded by the first surface 511, the seventh surface 517, the second surface 512, and the eighth surface 518 in the cross section. Similarly, the second bonded magnet piece 510B has a ninth surface 519 and a tenth surface 520 that connect the third surface 513 and the fourth surface 514 in the cross-sectional view. The second bonded magnet piece 510B also has a tapered outer shape surrounded by the third surface 513, the ninth surface 519, the fourth surface 514, and the tenth surface 520, and the outer shape in a plan view is tapered. . Furthermore, in a state where the first bonded magnet piece 510A and the second bonded magnet piece 510B are joined, the second surface 512 and the fourth surface 514 are formed in a U shape facing the same side. With such a configuration, the pole faces are exposed on the surface corresponding to the fan-shaped radius portion of each bond magnet piece, and the pole faces are joined so as to have different poles each other. A bonded magnet of a shape can be configured.

  For example, as shown in FIG. 39, by setting a set of a plurality of bond magnet pieces 510 as a bond magnet 500 arranged concentrically, it can be used also for a motor rotor. The bond magnet 500 shown in this figure is provided with a structure made of a material with high magnetic permeability for filling the space between adjacent sets of bond magnet pieces 510. A set of a plurality of bonded magnet pieces 510 is embedded in this structure to form a bonded magnet 500 having a cylindrical outer shape.

  Each bonded magnet piece can be formed by arranging orientation magnets 63 and 64 as shown in FIG.

Furthermore, as a modification, the bond magnet pieces 610A and 610B may be formed in a U shape or a track shape as shown in FIG.
Sixth Embodiment

  Furthermore, the present invention is limited to the configuration of the fifth embodiment in which one magnetic flux group is provided in one bonded magnet piece, and the first embodiment in which two magnetic flux groups are arranged side by side in the thickness direction on a common working surface. It is also possible to arrange the magnetic path groups horizontally in another configuration, for example, in a cross sectional view. Such an example is shown as Embodiment 6 in FIG. As shown in FIGS. 42 and 43, in this set of bonded magnet segments, two bonded magnet segments 710A and 710B are combined to constitute a bonded magnet 700. By connecting the upper surface of the bond magnet piece 710B and the lower surface of the bond magnet piece 710A, as shown in FIGS. 44 and 45, a bond magnet having two different magnetic poles on its side surface can be obtained. The bond magnets to be combined are formed such that their orientations are opposite to each other. That is, as shown in FIG. 45, when one magnet (first bonded magnet 710A) is formed with the first magnetic field line group 21 inside so that the south pole is on the lower surface 12 and the north pole is on the side surface 13, the other magnet (The second bond magnet 710B) forms an internal second magnetic field line group 22 such that the N pole is on the top surface 11 and the S pole is on the side surface 13. Then, the S pole on the lower surface of the first bond magnet 710A and the N pole on the upper surface of the second bond magnet 710B are connected by a suction force. As a result, the first magnetic field line group 21 and the second magnetic field line group 22 are coupled, the magnetic paths continue with each other, and as a result, the magnetic path inside the bond magnet 700 can be extended to improve the magnetic flux.

  Each bond magnet 710A, 710B can be formed individually. The first bond magnet 710A can be manufactured using the magnetic circuit devices 120 and 130 shown in FIGS. On the other hand, the orientation can be reversed by reversing the polarity of the orientation magnet in each magnetic circuit device. In other words, the second bonded magnet 710B can be manufactured by using one in which the N poles of the orientation magnets face each other and one in which the S poles face each other.

  FIG. 47 shows a magnetic circuit device 120 which constitutes a manufacturing apparatus for manufacturing a bonded magnet. The magnetic circuit device 120 includes a cavity 1220 filled with a bonded magnet composition containing a magnetic material and a resin, and orientation magnets 1214 a and 1214 b are disposed so as to sandwich the cavity 1220 in the vertical direction. The orientation magnets 1214 a and 1214 b apply a magnetic field to the cavity 1220 during molding of the bonded magnet in order to magnetically orient the magnetic material. The orientation magnets 1214 a and 1214 b are permanent magnets oriented in the direction in which the magnetic force is emitted perpendicularly to the non-acting surface of the bonded magnet of the molded product. The orientation magnets 1214a and 1214b are configured to have a first orientation magnet 1214a and a second orientation magnet 1214b, which are disposed such that the same poles (here, N poles) face each other, Thus, the first and second magnetic fields are applied with the same poles facing each other. Here, assuming that the axial direction of the alignment magnets 1214 a and 1214 b is the Z direction, the cavity 1220 is sandwiched between the first and second alignment magnets 1214 a and 1214 b in the Z direction. It is arranged biased to the side of the magnet 1214a.

Here, the first orientation magnet 1214a is disposed so as to face the non-acting surface of the molded product in the cavity 1220 with the partition wall of nonmagnetic steel material interposed therebetween. On the other hand, the second orientation magnet 1214 b is disposed at a distance (T ₁ ) substantially the same as the length (T ₂ ) of the cavity 1220 in the z direction. Nonmagnetic steel 1218 is disposed in a region where this cavity does not exist. In the cavity 1220, a yoke 1216 with a relative magnetic permeability of 100 to 1000000 is disposed on the side opposite to the side surface to be the working surface of the molded product. By arranging the orientation magnets 1214 a and 1214 b in this manner, N-S magnetic force lines are formed inside the cavity 1220 as shown by the curve in the figure. In addition, it is also preferable to additionally arrange an alignment magnet on the side of the cavity 1220 that faces the side surface that is the acting surface of the molded product. The cavity 1220 thus arranged is filled with a bonded magnet composition consisting of molten magnetic material and resin. While the bonded magnet composition is in a fluidized state, it is preferable that the orientation of the magnetic powder is maintained by orienting by applied magnetic field orientation, and cooling immediately after orientation by cooling by air or water.

  In this embodiment, two orienting magnets 1214 a and 1214 b are repelled to take out a strong radial magnetic field. Since the second orientation magnet 1214 b is formed apart from the cavity 1220, magnetic lines of force can be formed from the lower surface to the side surface so that the magnetic lines of force do not appear on the upper surface side of the bonded magnet piece. Since it is difficult for magnetic lines to come out on the upper surface, the magnetic lines converge on the side surface which is the working surface, and the magnetic flux lines per unit area increase.

Further, instead of the magnetic circuit device 120 of FIG. 47, a magnetic circuit device 130 shown in FIG. 48 can be used as a bond magnet piece or bond magnet manufacturing device. The orientation magnets 1315a and 1315b shown in this figure are formed in a cylindrical shape and are divided into eight equal parts by 45 degrees in the radial direction, and are oriented so that the magnetic force is emitted toward one point of the cylindrical lower surface There is. That is, the magnetization directions of the orientation magnets 1315a and 1315b are inclined inward with respect to the axial direction of the orientation magnets. At this time, the orientation direction θ with respect to the axial direction of each magnet is 34 degrees with respect to the axis of the orientation magnet. The orientation magnets 1315 a and 1315 b thus formed are arranged in a mirror shape so that the same poles face each other so that the magnetic force is concentrated in the direction of the cavity 1320. Further, as in the example of FIG. 47, the second alignment magnet 1315b is disposed at substantially the same distance (T ₁ ) as the length (T ₂ ) of the cavity 20 in the z direction. By arranging the orientation magnets 1315 a and 1315 b in this manner, N—S magnetic force lines are formed inside the cavity 1320 as shown by the curves in the drawing. In the magnetic circuit device 130, the configuration similar to that of FIG. 47 can be used for the configuration of the yoke 1316 and the nonmagnetic steel 1318, and the configuration of adding an orientation magnet on the side facing the side, I omit it.

  Here, FIG. 44 shows the alignment state of the magnetization easy axis of the magnetic powder particle in the VIC-VIC line cross section of the disk-like bond magnet 700 shown in FIG. 42 and the like. By combining the surfaces (upper and lower surfaces: Sb) adjacent to the side working surface (Sa), a magnet having two magnetic poles on the working surface (Sa) is obtained. In addition, in the Sb plane, since only molded articles having different magnetic poles are combined, they can be easily combined. By combining in this manner, in addition to the extension of the magnetic path between the two magnets and the improvement of the surface magnetic flux density, it is possible to reduce the leakage magnetic flux density from other than the working surface.

  Furthermore, as shown in FIG. 46, the direction of the magnetic flux lines of the bond magnet 700 'in which the two bond magnet pieces 710A and 710B are bonded can be configured in the opposite direction to that of FIG. In this example, the bond magnet 700 of FIG. 45 is turned upside down, the second bond magnet piece 710B is disposed on the upper side, the first bond magnet piece 710A is disposed on the lower side, and the bonding surface of the second bond magnet piece 710B. By arranging so that a certain N pole face and an S pole face that is the joining face of the first bonded magnet 710 A face each other, the magnetic paths are coupled and extended in the joining face, and as a result, the side faces are exposed. The surface magnetic flux density of the magnetic pole can be improved. Further, by alternately stacking sets of such disk-shaped first bond magnets 710A and second bond magnets 700B magnets, it is possible to obtain a bond magnet in which magnetic poles are alternately exposed on cylindrical side surfaces. At this time, the bonding surfaces of the bonded magnet pieces are parallel to each other.

  In particular, in the configuration in which the coupling surface as described above is flat and the side surface is the pole face, the magnetic flux of the planar coupling surface having a relatively large area is concentrated to the magnetic pole on the side surface having a relatively small area. Thus, a convergent orientation in which the magnetic flux is converged can be realized, and the magnetic flux density of the magnetic pole can be effectively improved. That is, as shown in FIG. 45, the convergent orientation is realized by making the distance a 'between the magnetic lines of force on the action surface smaller than the distance b' between the same magnetic lines of force on the non-action surface. Here, a '<b' is connected to the magnitude of the magnetic flux density, and is high in combination with the parabolic orientation in which the magnetic path is lengthened by bending from a linear shape to improve the magnetic force. Surface magnetic flux density can be realized.

As described above, according to the bond magnet of the embodiment of the present invention, while achieving pole orientation, the magnetic path is oriented so as to be deeply wound toward the cylindrical center of the bond magnet. There is. Further, at a portion deep from the bonded magnet surface (working surface), a magnetic pole (non-working surface) in which the distance between the magnetic paths is widely oriented is formed, and the non-working surfaces of adjacent bonded magnet pieces are formed. By joining so as to have different magnetic poles, the magnetic path is continued at this junction interface, and the magnetic path is elongated. As described above, by orienting the magnetic path from the surface to the inside of the cylindrical bonded magnet so as to be deeply wound, it is possible to raise the operating point of the BH line shown in FIG. Furthermore, by widening the magnetic pole of the non-working surface and narrowing the magnetic pole of the working surface, the convergent orientation is simultaneously realized from the wide magnetic pole to the narrow magnetic pole, and such pole orientation and convergent orientation are simultaneously realized. It is possible to realize an extremely high surface magnetic flux density and to exhibit the same level of magnetic flux as a sintered magnet while being a bonded magnet.

  In addition, the bonded magnet manufactured as described above can be embedded in a material having high permeability, such as silicon steel. For example, in the example of FIG. 39, a bonded magnet molded product can be configured by arranging the set of bonded magnet pieces of FIG. 38 around the rotation axis and arranging a high magnetic permeability material in the gap.

  Moreover, according to the above configuration, it is possible to realize a side-oriented bonded magnet with little leakage flux from other than the working surface, and a field unit using the same. In addition, it is possible to realize a method of manufacturing a bonded magnet in which a sufficient orientation magnetic field can be obtained in response to thinning of the bonded magnet.

  Moreover, according to the above configuration, it is possible to reduce the leakage flux from other than the action surface of the bond magnet. As a result, a flat side-oriented bonded magnet and a field unit using the same are realized.

  In the above example, samarium iron nitrogen magnet is used as magnet powder used for bond magnet, but the present invention is not limited to this, for example, it is possible to use rare earth magnet such as samarium cobalt magnet, neodymium magnet, praseodymium magnet, etc. it can.

  The bonded magnet of the present invention can be suitably used as a substitute for a sintered magnet used in a small motor using a permanent magnet. In addition, it can be applied to applications where surface magnetic flux density and field magnetic field are required. For example, by applying to various shapes, segment magnets for precision motors, VCM magnets for HDD, magnets for various sensors that use magnetic signals such as for bill sensors, magnets for health appliances, magnets for removing foreign matter and magnets for linear motors In particular, it can be suitably used as a magnet for a thin actuator represented by a speaker magnet used for a thin TV and the like.

100, 200, 300, 400, 500, 700, 700 '... bonded magnets 10, 510, 610A, 610B, 710A, 710B ... bonded magnet pieces 10A, 510A ... first bonded magnet pieces 10B, 510B ... second bonded magnet pieces 11, 511 ... first surface (first non-operating surface)
12, 512 ... second surface (first working surface)
13, 513 ... third surface (second non-operating surface)
14, 514 ... fourth surface (second action surface)
15: Fifth surface (third non-operating surface)
16: Sixth surface (fourth non-operating surface)
517 seventh surface 518 eighth surface 519 ninth surface 520 tenth surface 21 first magnetic field line group 22 second magnetic field line group 23 third magnetic field line group 24 fourth magnetic field line group 530 structural body 61 First non-working surface alignment magnet 62: first working surface alignment magnet 63: alignment magnet 64: alignment magnet 66: yoke 65: third non-working surface alignment magnet 61 ': first non-working surface alignment Electromagnets 62 ': first working surface orienting electromagnets 65': third non-working surface orienting electromagnets 66 ': yokes 120, 130: magnetic circuit devices 1214a, 1214b, 1315a, 1315b: orientation magnets 1216, 1316 ... yoke 1218 , 1318 ... nonmagnetic steel 1220, 1320 ... cavity

Claims (14)

First side,
A second surface contacting with the first surface via a joint portion;
And a fifth surface which is in contact with the second surface via a bonding portion and in contact with the first surface via the bonding portion,
The first surface and the fifth surface are inclined at a constant central angle, and the outer shape in a sectional view surrounded by the first surface, the fifth surface, and the second surface is fan-shaped.
A first magnetic flux line group directed from the first surface to the second surface;
A first bonded magnet piece having a third magnetic field line group directed from the fifth surface to the second surface;
The third side,
A fourth surface that is in contact with the third surface via a joint portion;
And a sixth surface which is in contact with the fourth surface via a joint portion and in contact with the third surface via the joint portion,
The third surface and the sixth surface are inclined at a constant central angle, and the outer shape in a sectional view surrounded by the third surface, the sixth surface, and the fourth surface is fan-shaped.
A second magnetic field line group directed from the fourth surface to the third surface;
And a second bonded magnet piece having a fourth magnetic field line group directed from the fourth surface to the sixth surface,
The magnetic flux density of the second surface is higher than the magnetic flux density of the first surface,
The magnetic flux density of the fourth surface is higher than the magnetic flux density of the third surface,
The magnetic pole of the first surface and the magnetic pole of the third surface have different polarities,
The first surface and the third surface are connected, and the second magnetic field line group and the first magnetic field line group are configured to be continuous.
Magnetic poles different from each other on the second surface and the fourth surface are exposed to the outside,
A sector of the first bond magnet piece,
A length A corresponding to the radius,
Length B of the magnetized portion of the portion corresponding to the arc
When the ratio A / B with is n = the number of magnetic poles,
In the case of 12 poles or less (central angle θ ₀ 30 30),
0.3184 n ≦ (A / B) <− 0.04 n ³ +1.47 n ² −14.03 n + 43
If it is larger than 12 poles (θ ₀ <30),
0.3184 n ≦ (A / B)
And
The first bonded magnet piece and the second bonded magnet piece include at least a magnetic material and a resin,
The bonded magnet whose said magnetic material is either a Sm-Co type | system | group, a Nd-Fe-B type | system | group, and a Sm-Fe-N type | system | group. The bonded magnet according to claim 1, wherein
The area of the first surface is wider than the area of the second surface,
The bonded magnet which makes the area of the said 3rd surface wider than the area of the said 4th surface. A bonded magnet according to claim 1 or 2,
The sum of the areas of the first surface and the fifth surface is larger than the area of the second surface,
The bonded magnet which makes the sum of the area of the said 3rd surface and a 6th surface wider than the area of the said 4th surface. The bonded magnet according to any one of claims 1 to 3, wherein
The bonded magnet whose angle which the said 1st surface and a 2nd surface cross | intersect is 90 degrees or less. It is a bonded magnet as described in any one of Claims 1-4,
The bonded magnet which makes the said 2nd surface an action surface, and does not make magnetic flux appear outside from the surface of the said 1st bonded magnet piece on the opposite side to this 2nd surface. The bonded magnet according to any one of claims 1 to 5 , wherein
A joint portion between the first surface and the second surface, a joint portion between the first surface and the fifth surface, a joint portion between the third surface and the fourth surface, or a joint between the third surface and the sixth surface The bonded magnet in which at least one of the joint portions is linear. The bonded magnet according to any one of claims 1 to 6 , wherein
A joint portion between the first surface and the second surface, a joint portion between the first surface and the fifth surface, a joint portion between the third surface and the fourth surface, or a joint between the third surface and the sixth surface The bonded magnet by which at least one of the junction parts is formed in concave shape. First side,
And a second surface contacting with the first surface via a joint portion,
A first bonded magnet piece having a first group of magnetic field lines directed from the first surface to the second surface;
The third side,
And a fourth surface contacting with the third surface via a joint portion,
And a second bonded magnet piece having a second group of magnetic field lines directed from the fourth surface to the third surface,
The area of the first surface is larger than the area of the second surface, and the magnetic flux density of the second surface is higher than the magnetic flux density of the first surface,
The area of the third surface is larger than the area of the fourth surface, and the magnetic flux density of the fourth surface is higher than the magnetic flux density of the third surface,
The magnetic pole of the first surface and the magnetic pole of the third surface have different polarities,
The first surface and the third surface are connected, and the second magnetic field line group and the first magnetic field line group are configured to be continuous.
Different magnetic poles are exposed to the outside on the second surface and the fourth surface,
The first bonded magnet piece has a flat outer shape,
The flat main surface is the first surface, and the flat surface in the thickness direction is the second surface,
In the inside of the said 1st bonded magnet piece, the bonded magnet which a line of magnetic force bends symmetrically toward the 2nd surface side from the said 1st surface. The bonded magnet according to claim 8 , wherein
The second bonded magnet piece has a flat outer shape,
The flat main surface is the third surface, and the flat surface in the thickness direction is the fourth surface.
In the inside of the said 2nd bonded magnet piece, the bonded magnet by which a magnetic force line is bent symmetrically toward the 3rd surface side from the said 4th surface. The bonded magnet according to any one of claims 1 to 9 , wherein
The bonded magnet whose distribution of the line of magnetic force in each inside of said 1st bonded magnet piece and said 2nd bonded magnet piece is substantially symmetrical. The bonded magnet according to any one of claims 1 to 10 , wherein
A bonded magnet formed by bonding the bonding surfaces of the first bonded magnet piece and the second bonded magnet piece. The first non-working surface,
A first working surface in contact with the first non-working surface via a junction;
And a third non-working surface in contact with the first working surface via a bonding portion and in contact with the first non-working surface via the bonding portion,
The first non-operating surface and the third non-operating surface are inclined at a constant central angle, and the outer shape in a sectional view surrounded by the first non-operating surface, the third non-operating surface, and the first operating surface is fan-shaped A method of manufacturing a bonded magnet,
Filling a bonded magnet composition containing a magnetic material and a resin into a cavity of a molding die;
Applying a magnetic field for orientation to the cavity to form a bonded magnet;
The orientation magnetic field is formed by a permanent magnet,
In the cavity, a first non-working surface alignment magnet at a portion corresponding to the first non-working surface of the bond magnet, a third non-working surface alignment magnet at a portion corresponding to the third non-working surface, The first working surface alignment magnet is disposed opposite to each other at a portion corresponding to one working surface,
The corresponding portions of the first non-working surface alignment magnet and the third non-working surface alignment magnet are the same magnetic pole,
The corresponding portion of the first working surface alignment magnet is a magnetic pole different from the first non-working surface alignment magnet and the third non-working surface alignment magnet,
The manufacturing method of the bonded magnet whose said magnetic material is either Sm-Co type, Nd-Fe-B type, or Sm-Fe-N type. The first non-working surface,
A method of manufacturing a flat bond magnet comprising: the first non-operating surface; and the first operating surface in contact with the bonding portion.
Providing a cavity of a molding die filled with a bonded magnet composition comprising a magnetic material and a resin;
Filling the molten bond magnet composition into the cavity and applying a magnetic field to orient the magnetic material to form a bond magnet.
The magnetic field is configured to have first and second magnetic fields applied so that the same poles face each other,
The cavity is biased toward the first magnetic field side so as to be sandwiched between the first and second magnetic fields in the facing direction of the magnetic field.
A method of manufacturing a bonded magnet, wherein the second magnetic field is formed at a distance substantially the same as the length of the cavity in the opposite direction of the magnetic field. The first non-working surface,
A method of manufacturing a flat bond magnet comprising: the first non-operating surface; and the first operating surface in contact with the bonding portion.
Providing a mold mold cavity filled with a bonded magnet composition comprising a magnetic material and a resin;
The magnetic material is applied by applying a magnetic field with an orientation magnet for filling the melted bond magnet composition in the cavity and facing the cavity and for orienting the magnetic material magnetically. And orienting to form a bonded magnet.
The orientation magnet is configured to have first and second orientation magnets disposed such that the same poles face each other,
The cavity is biased toward the first alignment magnet so as to be sandwiched between the first and second alignment magnets in the axial direction of the alignment magnet.
A method of manufacturing a bonded magnet, wherein the second alignment magnet is disposed with a distance substantially the same as the length of the cavity in the axial direction of the alignment magnet.