JP2006222131A - Permanent magnet body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent magnet body having the large maximum value of surface magnetic flux density on a main surface. <P>SOLUTION: The permanent magnet body 10 includes a plurality of permanent magnet pieces 12. The permanent magnet pieces 12 each have a polar anisotropic performance, and the magnetization direction thereof is a direction in which the magnetization is bent from a main surface 12a side toward a main surface 12b side and returns to the main surface 12a side, and a direction in which the magnetization is bent from the main surface 12b side to the main surface 12a side and returns to the main surface 12b side. The permanent magnet body 10 is constituted by arranging the plurality of permanent magnetic pieces 12 so that the same poles may oppose each other and coupling them, and an N-pole or an S-pole is formed on a portion where the adjacent permanent magnets 12 contact on the main surfaces 10a and 10b of the permanent magnet body 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a permanent magnet body, and more particularly to an annular permanent magnet body formed on a main surface so that two or more even number of magnetic poles are arranged in a circumferential direction.

Conventionally, as disclosed in Patent Document 1, for example, an axial gap motor is known to use an annular permanent magnet body formed on a main surface so that a plurality of magnetic poles are arranged in the circumferential direction. Yes. For example, in the permanent magnet body 1 shown in FIGS. 10A and 10B, a plurality of permanent magnet pieces 2 whose magnetization directions are parallel to the axial direction (arrow B direction) are arranged in the circumferential direction (arrow A direction). N poles and S poles are formed on main surfaces 1a and 1b so that they are alternately arranged in the direction of arrow A. In the axial gap type motor using such a permanent magnet body 1, a magnetic flux L {see FIG. 10 (b)} acts on a coil arranged to face at least one of the main surfaces 1a and 1b. Works by. Such a permanent magnet body 1 is used in many devices such as a magnetic sensor in addition to an axial gap type motor.
JP-A-8-214527

However, in recent years, there has been a demand for a permanent magnet body having a large maximum value of the surface magnetic flux density on the main surface in order to reduce the size and increase the output of a device using the permanent magnet body. It was difficult to fully meet the requirements.
Therefore, a main object of the present invention is to provide a permanent magnet body having a large maximum value of the surface magnetic flux density on the main surface.

  In order to achieve the above-described object, the permanent magnet body according to claim 1 is an annular permanent magnet in which an even number of two or more magnetic poles are alternately arranged in the circumferential direction on at least one main surface. It is a magnet body and has polar anisotropy between different poles adjacent to each other in the circumferential direction among the magnetic poles.

  According to a second aspect of the present invention, there is provided a permanent magnet body according to the first aspect, wherein the permanent magnet body is constituted by one annular permanent magnet.

  According to a third aspect of the present invention, there is provided the permanent magnet body according to the first aspect, wherein a plurality of permanent magnet pieces are arranged in the circumferential direction, and at least one permanent magnet piece is an adjacent permanent magnet piece. The same poles are opposite to each other.

  The permanent magnet body according to claim 4 is an annular permanent magnet body formed on one main surface so that two or more even number of magnetic poles are alternately arranged in the circumferential direction, and the magnetization direction is an axis. A first permanent magnet piece parallel to the direction and a second permanent magnet piece whose magnetization direction is perpendicular to the radial direction and the axial direction, and the first permanent magnet pieces and the second permanent magnet pieces are alternately arranged in the circumferential direction. The first permanent magnet pieces adjacent to each other with the second permanent magnet piece sandwiched are opposite to each other, and the second permanent magnet pieces adjacent to each other across the first permanent magnet piece are opposite to each other.

  The permanent magnet body according to claim 5 is arranged such that the other main surfaces of the permanent magnet body according to claim 4 face each other and the first permanent magnet pieces face each other with the same poles facing each other in the axial direction. It is configured by arranging two in the.

  A permanent magnet body according to a sixth aspect is the permanent magnet body according to the fifth aspect, wherein a magnetic body is disposed between the permanent magnet bodies according to the fourth aspect.

  The permanent magnet body according to claim 7 is an annular permanent magnet body formed on the main surface so that even numbers of two or more magnetic poles are alternately arranged in the circumferential direction, and the magnetization direction is a radial direction. And permanent magnet pieces orthogonal to the axial direction, and a magnetic body, the permanent magnet pieces and the magnetic body are alternately arranged in the circumferential direction, and the permanent magnet pieces adjacent to each other across the magnetic body face each other with the same polarity.

  The “circumferential direction”, “axial direction”, and “radial direction” are the circumferential direction, axial direction, and radial direction of the permanent magnet body, respectively.

  In the permanent magnet body according to claim 1, by having polar anisotropy between different poles adjacent in the circumferential direction (between N pole and S pole) among two or more even number of magnetic poles, More magnetic flux can be concentrated on the magnetic pole (N pole) on the surface. Therefore, the maximum value of the surface magnetic flux density on the main surface can be increased as compared with the conventional permanent magnet body.

  The permanent magnet body may be constituted by one annular permanent magnet as described in claim 2, and may be constituted by arranging a plurality of permanent magnet pieces in an annular shape as described in claim 3. May be.

  In the permanent magnet body according to claim 4, in the first permanent magnet pieces adjacent to each other with the second permanent magnet piece interposed therebetween, an N pole is formed on one main surface of one of the first permanent magnet pieces, and the other first permanent magnet piece. An S pole is formed on one main surface of the permanent magnet piece. Thus, in the first permanent magnet pieces adjacent to each other with the second permanent magnet piece interposed therebetween, the magnetic flux is concentrated on the magnetic pole (N pole) of one first permanent magnet piece, and the magnetic flux from the magnetic pole is concentrated on the other first permanent magnet piece. It can be efficiently converged on the magnetic pole (S pole) of the magnet piece. That is, by reducing the magnetic flux (leakage magnetic flux) generated on the other main surface of the permanent magnet body, the magnetic flux can be concentrated on the magnetic pole formed on the one main surface. Therefore, the maximum value of the surface magnetic flux density on the one main surface can be made larger than that of the conventional permanent magnet body.

  According to a fifth aspect of the present invention, the permanent magnet bodies according to the fourth aspect of the present invention are arranged so that the other principal surfaces of the permanent magnet bodies are opposed to each other and the first permanent magnet pieces are aligned with the same poles facing each other in the axial direction. Permanent magnet bodies may be configured by arranging two. Thereby, a high surface magnetic flux density can be obtained on both main surfaces of the permanent magnet body.

  When two permanent magnet bodies according to claim 4 are arranged in the axial direction, repulsion can be suppressed by arranging a magnetic body between the two permanent magnet bodies as described in claim 6. The assembly work can be facilitated.

  In the permanent magnet body according to claim 7, the magnetic body functions as a magnetic pole piece, and in the adjacent magnetic body with the permanent magnet piece interposed therebetween, the magnetic flux is concentrated on the main surface of one of the magnetic bodies, and the main body of the magnetic body is The magnetic flux from the surface can be efficiently converged on the main surface of the other magnetic body. Therefore, the maximum value of the surface magnetic flux density on the main surface can be increased as compared with the conventional permanent magnet body.

  According to the present invention, it is possible to obtain a permanent magnet body having a large maximum surface magnetic flux density on the main surface.

Embodiments of the present invention will be described below with reference to the drawings.
1 (a) and 1 (b), a permanent magnet body 10 according to an embodiment of the present invention includes a plurality (eight in this case) of permanent magnet pieces 12 and surrounds the eight permanent magnet pieces 12. By arranging and connecting in the direction (arrow A direction), it is configured in an annular shape.

  Referring also to FIG. 2, permanent magnet piece 12 having a substantially sectoral cross section has main surfaces 12 a and 12 b and opposed surfaces 12 c and 12 d facing adjacent permanent magnet pieces 12. As the permanent magnet piece 12, for example, a rare earth sintered magnet is used.

  The magnetization direction of the permanent magnet piece 12 is a direction that curves from the corner portion of the main surface 12a and the opposing surface 12c toward the main surface 12b side and extends to the corner portion of the main surface 12a and the opposing surface 12d, and the main surface 12b. This is a direction that curves from the corner of the opposing surface 12c to the main surface 12a and extends to the corner of the main surface 12b and the opposing surface 12d. Therefore, as shown in the permanent magnet piece 12 in FIG. 2, a magnetic pole (N pole) is formed in the vicinity of the corner between the main surface 12a and the facing surface 12d, and in the vicinity of the corner between the main surface 12a and the facing surface 12c. Is formed with a magnetic pole (S pole). Similarly, a magnetic pole (N pole) is formed in the vicinity of the corner between the main surface 12b and the opposing surface 12d, and a magnetic pole (S pole) is formed in the vicinity of the corner between the main surface 12b and the opposing surface 12c.

  Such a permanent magnet piece 12 is produced using, for example, a powder press apparatus. Specifically, as shown in FIG. 3, first, a rare earth alloy powder is filled in the cavity between the upper punch 50a, the lower punch 50b, and the die 52 of the powder press apparatus. Then, the rare earth alloy powder is press-molded by the upper punch 50a and the lower punch 50b while applying an orientation magnetic field having the same strength by the orientation coils 54 provided inside and outside the upper punch 50a and inside and outside the lower punch 50b. Thus, a permanent magnet piece 12 having polar anisotropy between the N pole and S pole on the main surface 12a side and having a polar anisotropy between the N pole and S pole on the main surface 12b side is produced. Is done.

  Returning to FIG. 1, the permanent magnet body 10 is configured by connecting eight permanent magnet pieces 12 so that the same poles face each other, and the permanent magnet pieces 12 adjacent to the main surfaces 10 a and 10 b of the permanent magnet body 10. A magnetic pole (N-pole or S-pole) is formed at the portion where the contacts. Therefore, eight magnetic poles are alternately arranged in the direction of arrow A on the main surfaces 10a and 10b of the permanent magnet body 10, and the permanent magnet body 10 has polar anisotropy between adjacent magnetic poles.

  In such a permanent magnet body 10, as shown in FIG. 1 (b), more magnetic flux L can be concentrated on the magnetic poles (N poles) of the main surfaces 10a and 10b. The maximum value of the surface magnetic flux density on main surfaces 10a and 10b can be increased. When such a permanent magnet body 10 is used for the rotor of an axial gap type motor, the magnetic flux linked to the coil increases, so that the torque of the motor can be increased or the motor can be made compact.

  In addition, although the above-mentioned embodiment demonstrated the case where each permanent magnet piece 12 was arrange | positioned so that the same pole might oppose the adjacent permanent magnet piece 12, at least 1 permanent magnet piece 12 and the adjacent permanent magnet piece 12 and What is necessary is just to arrange | position so that the same pole may oppose.

  Moreover, although the above-mentioned embodiment demonstrated the case where the permanent magnet piece 12 with two magnetization directions was used, only the direction where the magnetization direction curves from one main surface side to the other main surface side and returns to the one main surface side. You may comprise a permanent magnet body using a permanent magnet piece. In this case, the magnetic pole is formed only on one main surface of the permanent magnet body. The permanent magnet piece whose magnetization direction is curved from one main surface side to the other main surface side and returns to the one main surface side is, for example, a non-magnetic material having no coil in place of the upper punch 50a or the lower punch 50b. This punch is used to apply an orientation magnetic field only from either the upper side or the lower side (see FIG. 3).

  Moreover, although the above-mentioned embodiment demonstrated the case where the permanent magnet body 10 was comprised using the several permanent magnet piece 12, it is a main surface so that two or more even-numbered magnetic poles may arrange a different pole in the circumferential direction alternately. The permanent magnet body may be configured by using one annular permanent magnet having polar anisotropy.

Next, a permanent magnet body 100 according to another embodiment of the present invention will be described.
Referring to FIGS. 4A and 4B, permanent magnet body 100 includes a plurality (here, eight) of permanent magnet pieces 102 and the same number of permanent magnet pieces 104 as permanent magnet pieces 102. Permanent magnet pieces 102 and 104 are rare earth sintered magnets having a substantially fan-shaped cross section. The permanent magnet body 100 is formed in an annular shape by alternately arranging and connecting the permanent magnet pieces 102 and 104 in the direction of arrow A.

  Referring also to FIG. 5, the magnetization direction of permanent magnet piece 102 is parallel to the axial direction (arrow B direction), and the magnetization direction of permanent magnet piece 104 is radial (arrow C direction) and arrow B direction. The directions are orthogonal. In this embodiment, the permanent magnet piece 102 corresponds to a first permanent magnet piece, and the permanent magnet piece 104 corresponds to a second permanent magnet piece.

  As shown in the permanent magnet piece 102 in FIG. 5, the permanent magnet pieces 102 that are adjacent to each other with the permanent magnet piece 104 interposed therebetween are arranged so that the opposite poles, that is, the N and S poles face each other. Further, as shown in the permanent magnet piece 104 in FIG. 5, the permanent magnet pieces 104 adjacent to each other with the permanent magnet piece 102 are in the same polarity, that is, the N pole and the N pole face each other, or the S pole and the S pole. Are arranged so as to face each other. Thus, an N pole is formed on one main surface 102 a of the permanent magnet piece 102 sandwiched between the N poles of the two permanent magnet pieces 104, and one of the permanent magnet pieces 102 sandwiched between the S poles of the two permanent magnet pieces 104. An S pole is formed on the main surface 102a. Therefore, four N-poles and four S-poles are alternately arranged in the direction of arrow A on one main surface 100a of permanent magnet body 100.

  In such a permanent magnet body 100, as shown in FIG. 4B, in the permanent magnet pieces 102 adjacent to each other with the permanent magnet pieces 104 interposed therebetween, the magnetic poles (N poles) on one main surface 102a of one permanent magnet piece 102 are arranged. ) And the magnetic flux L from the magnetic pole (N pole) can be efficiently converged on the magnetic pole (S pole) of the one main surface 102a of the other permanent magnet piece 102. That is, the magnetic flux generated from the magnetic pole (N pole) of the permanent magnet piece 102 on the other main surface 100b is attracted to the permanent magnet piece 104 without being basically generated on the other main surface 100b, and the permanent magnet piece 104. The magnetic flux generated from the permanent magnet piece 104 is attracted to the one main surface 100a without being generated on the other main surface 100b by the adjacent permanent magnet piece 102. Therefore, in the permanent magnet body 100, the magnetic flux (leakage magnetic flux) generated on the other main surface 100b can be reduced, and the magnetic flux can be concentrated on the magnetic pole formed on the one main surface 100a. Therefore, the maximum value of the surface magnetic flux density on the one main surface 100a can be made larger than that of the conventional permanent magnet body.

  Further, in the permanent magnet body 100, by changing the ratio of the size of the permanent magnet pieces 102 and 104, in other words, the ratio of the area of the one main surface 102a of the permanent magnet piece 102 to the area of the one main surface 100a, The surface magnetic flux density distribution can be changed according to the application.

Next, a permanent magnet body 200 according to another embodiment of the present invention will be described.
6 (a) and 6 (b), permanent magnet body 200 includes two permanent magnet bodies 100 described above, and is configured by arranging and connecting two permanent magnet bodies 100 in the direction of arrow B. The

  Specifically, in the permanent magnet body 200, the two permanent magnet bodies 100 are arranged upside down so that the other main surface 100b {see FIGS. 4 (a) and (b)} faces each other, and each permanent magnet piece. 102 and permanent magnet pieces 104 are arranged so as to be aligned in the direction of arrow B, respectively. In the permanent magnet body 200, the same poles of the permanent magnet pieces 102 arranged in the direction of arrow B are opposed to each other.

  In such a permanent magnet body 200, the maximum value of the surface magnetic flux density on one main surface and the other main surface can be increased. It goes without saying that the one main surface and the other main surface of the permanent magnet body 200 correspond to the one main surface 100 a of the permanent magnet body 100.

  When two permanent magnet bodies 100 are connected in the direction of arrow B, a hollow disc-shaped insertion member 202 made of a magnetic body is interposed between the two permanent magnet bodies 100 as in the permanent magnet body 200a shown in FIG. You may arrange. By disposing the insertion member 202 between the two permanent magnet bodies 100 in this way, repulsion between the permanent magnet bodies 100 can be suppressed, and the assembling work is facilitated.

Next, a permanent magnet body 300 according to another embodiment of the present invention will be described.
Referring to FIGS. 8A and 8B, permanent magnet body 300 includes a plurality (here, eight) of permanent magnet pieces 302 and the same number of magnetic materials 304 as permanent magnet pieces 302. The permanent magnet piece 302 is a rare earth sintered magnet formed in a substantially sectoral cross section. The magnetic material 304 is a magnetic body having a substantially sectoral cross section, and is made of, for example, powdered iron or silicon steel. The permanent magnet body 300 is configured in an annular shape by alternately arranging and connecting the permanent magnet pieces 302 and the magnetic material 304 in the direction of arrow A.

  The magnetization direction of the permanent magnet piece 302 is a direction orthogonal to the arrow C direction and the arrow B direction. In the permanent magnet body 300, the adjacent permanent magnet pieces 302 with the magnetic material 304 interposed therebetween are arranged so that the same poles face each other. Therefore, on the main surface 300a of the permanent magnet body 300, eight N poles and eight S poles are arranged in the direction of arrow A so that the main surface 304a of the magnetic material 304 is sandwiched between the same poles. Similarly, in the main surface 300b, the N pole and the S pole are arranged in the direction of the arrow A so that the main surface 304b of the magnetic material 304 is sandwiched between the same poles.

  In such a permanent magnet body 300, the magnetic material 304 functions as a pole piece. As a result, as shown in FIG. 8B, in the magnetic material 304 adjacent to the permanent magnet piece 302, the magnetic flux L is concentrated on the main surface 304a of one magnetic material 304, and the magnetic flux from the magnetic material 304 is concentrated. L can be efficiently converged on the main surface 304a of the other magnetic material 304. The same applies between the main surfaces 304b of the adjacent magnetic members 304. Therefore, the maximum value of the surface magnetic flux density on the main surfaces 300a and 300b can be made larger than that of the permanent magnet body of the prior art.

  Further, in the permanent magnet body 300, the ratio of the size of the permanent magnet piece 302 and the magnetic material 304, in other words, the ratio of the area of the main surface 304a (304b) of the magnetic material 304 to the area of the main surface 300a (300b). By changing, it can be changed to the surface magnetic flux density distribution according to the application.

  The permanent magnets used for the permanent magnet pieces 12, 102, 104 and 302 are not limited to rare earth sintered magnets. For example, a rare earth bonded magnet may be used as the permanent magnet pieces 12, 102, 104, and 302 instead of the rare earth sintered magnet. Besides the rare earth magnets, any permanent magnets such as alnico magnets and ferrite magnets can be selected as the permanent magnet pieces 12, 102, 104 and 302.

  Next, a comparative example of the surface magnetic flux density distribution between the permanent magnet bodies 10, 200 and 300 of the present invention and the conventional permanent magnet body 1 shown in FIGS. 10 (a) and 10 (b) will be described. Here, a comparative example when measuring the surface magnetic flux density by unifying the shape and size of each permanent magnet body and unifying the material of the permanent magnet piece used for each permanent magnet body will be described.

  Referring to FIG. 9, a waveform W1 indicated by a solid line is a surface magnetic flux density distribution at a height of 0.5 mm on a line connecting the points X1 of the main surface 10a of the permanent magnet body 10 {see FIG. 1 (a). }. A waveform W2 indicated by a one-dot chain line is a surface magnetic flux density distribution at a height of 0.5 mm on a line connecting the points X2 of one main surface of the permanent magnet body 200 (one main surface 100a of the permanent magnet body 100) {FIG. See 6 (a)}. A waveform W3 indicated by a two-dot chain line is a surface magnetic flux density distribution at a height of 0.5 mm on a line connecting the points X3 of the main surface 300a of the permanent magnet body 300 {see FIG. 8A}. A waveform W4 indicated by a broken line is a surface magnetic flux density distribution at a height of 0.5 mm on a line connecting the points X4 of the main surface 1a of the permanent magnet body 1 {see FIG. 10 (a)}.

  From the waveforms W1 to W4, the maximum value of the surface magnetic flux density on the main surface of each of the permanent magnet bodies 10, 200 and 300 may be larger than the maximum value of the surface magnetic flux density on the main surface 1a of the permanent magnet body 1. Recognize. In the permanent magnet body 10, the surface magnetic flux density is maximized on the center (N pole) of the line connecting the points X1 by arranging the permanent magnet pieces 12 having polar anisotropy so that the same poles face each other. In particular, it can be seen that the maximum value of the surface magnetic flux density is increased.

  Such permanent magnet bodies 10, 200 and 300 are suitably used for axial gap motors, magnetic sensors, and the like. In the permanent magnet body 10, since the surface magnetic flux density distribution becomes a sinusoidal waveform by disposing the permanent magnet pieces 12 having polar anisotropy so that the same poles face each other, the permanent magnet body 10 is formed into an axial gap type. When used in a motor, torque ripple can be reduced.

The permanent magnet body of one Embodiment of this invention is shown, (a) is a perspective view solution figure, (b) is a side view solution figure. It is a perspective view solution figure which shows the permanent magnet piece used for the permanent magnet body of FIG. It is an illustration figure which shows the preparation aspect of the permanent magnet piece of FIG. The permanent magnet body of other embodiment of this invention is shown, (a) is a perspective view solution figure, (b) is a side view solution figure. It is a perspective view solution figure which shows a part of permanent magnet body of FIG. The permanent magnet body of other embodiment of this invention is shown, (a) is a perspective view solution figure, (b) is a side view solution figure. It is a perspective view solution figure which shows the permanent magnet body of other embodiment of this invention. The permanent magnet body of other embodiment of this invention is shown, (a) is a perspective view solution figure, (b) is a side view solution figure. It is an illustration figure which shows the comparative example of the surface magnetic flux density distribution of the permanent magnet body of this invention, and the permanent magnet body of a prior art. The permanent magnet body of a prior art is shown, (a) is a perspective view solution figure, (b) is a side view solution figure.

Explanation of symbols

10, 100, 200, 200a, 300 Permanent magnet body 10a, 10b, 12a, 12b, 300a, 300b, 304a, 304b Main surface 12, 102, 104, 302 Permanent magnet piece 100a, 102a One main surface 100b The other main surface 202 Insertion member 304 Magnetic material

Claims (7)

An annular permanent magnet body formed such that at least one of the main surfaces has an even number of two or more magnetic poles alternately arranged with different polarities in the circumferential direction,
A permanent magnet body having polar anisotropy between different poles adjacent in the circumferential direction among the magnetic poles.   The permanent magnet body according to claim 1, wherein the permanent magnet body is constituted by one annular permanent magnet.   The permanent magnet body according to claim 1, wherein the permanent magnet body is configured by arranging a plurality of permanent magnet pieces in a circumferential direction, and at least one of the permanent magnet pieces has the same polarity as that of the adjacent permanent magnet piece. An annular permanent magnet body formed on one main surface so that two or more even number of magnetic poles are alternately arranged in different directions in the circumferential direction,
A first permanent magnet piece whose magnetization direction is parallel to the axial direction, and a second permanent magnet piece whose magnetization direction is perpendicular to the radial direction and the axial direction,
The first permanent magnet pieces and the second permanent magnet pieces are alternately arranged in the circumferential direction, and the first permanent magnet pieces adjacent to each other across the second permanent magnet pieces have opposite polarities and the first permanent magnet pieces are opposed to each other. A permanent magnet body in which the second permanent magnet pieces adjacent to each other across the permanent magnet pieces have the same polarity.   5. The permanent magnet body according to claim 4 is configured by arranging two permanent magnet bodies so that the other main surfaces thereof face each other and the first permanent magnet pieces of each other are aligned with the same poles facing each other in the axial direction. , Permanent magnet body.   The permanent magnet body according to claim 5, wherein a magnetic body is disposed between the permanent magnet bodies according to claim 4. An annular permanent magnet body formed on the main surface so that two or more even number of magnetic poles are alternately arranged in different directions in the circumferential direction,
A permanent magnet piece whose magnetization direction is perpendicular to the radial direction and the axial direction, and a magnetic body,
A permanent magnet body in which the permanent magnet pieces and the magnetic body are alternately arranged in the circumferential direction, and the permanent magnet pieces adjacent to each other with the magnetic body sandwiched therebetween have the same polarity.

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