JP2010040914A - Magnetization method of multi-pole magnet, and multi-pole magnet and magnetic encoder using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-pole magnet capable of improving the magnetization accuracy. <P>SOLUTION: In the magnetization method of the multi-pole magnet, a plurality of concavoconvex parts are provided on a side of a magnet material 1, and a magnet material 1, having a plurality of projecting parts 102 corresponding to a plurality of convex 203 of concavoconvex parts contacts with a magnetic yokes 2, in which a magnetizing coil 205 is wound so that a magnetization pattern on which N poles and S poles are aligned alternately on a concave part 204 of concavoconvex parts, to perform a magnetization. It is characterized that a plurality of projecting parts 102 are arranged, face to face with each other on convex 203 of concavoconvex parts of the magnetic yoke 2, and the magnetizing coil 205 is energized, to thereby magnetize a plurality of projecting parts 102. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method of magnetizing a multipolar magnet in which a large number of magnetic poles are magnetized on a magnet material, a multipolar magnet, and a magnetic encoder using the same, and in particular, the accuracy of magnetization in the large number of magnetic poles is improved. The present invention relates to a magnetizing method for a multipolar magnet, a multipolar magnet, and a magnetic encoder using the same.

Conventionally, a ring-shaped multipolar magnet has been used as a component of a magnetic encoder or the like. In such a ring-shaped multipolar magnet, for example, one in which a rotation detection magnetic pole is evenly magnetized over the entire circumference on one end face of the ring-shaped portion is known (see, for example, Patent Document 1). . In this multipolar magnet, a magnetizing yoke having a plurality of magnetizing poles arranged so that magnetizing winding coils are alternately wound, and generating magnetic lines substantially perpendicular to the magnetizing poles Magnetization is performed by.
Japanese Patent Laid-Open No. 7-74020

  However, in the magnetizing yoke used for magnetizing the conventional multi-pole magnet as described above, the winding coil is disposed so as to surround the magnetizing pole part by manual work or the like. It is difficult to ensure positional accuracy. For this reason, there is a problem that the magnetization pattern formed by the magnetic flux generated from such a winding coil becomes uneven, and the magnetization accuracy in the multipolar magnet is lowered.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a multipolar magnet magnetization method, a multipolar magnet, and a magnetic encoder using the same, which can improve the magnetization accuracy. And

  The method for magnetizing a multipolar magnet of the present invention has a plurality of uneven portions on the magnet material side, and is magnetized so as to form a magnetized pattern in which N and S poles are alternately arranged in the recesses of the uneven portions. A magnetizing method of a multi-pole magnet for magnetizing a magnet yoke having a plurality of projecting pieces corresponding to the convex portions of the concavo-convex portion to a magnetizing yoke around which a coil for winding is provided, The plurality of projecting pieces are arranged oppositely to the convex portions of the uneven portion of the yoke, and the plurality of projecting pieces are magnetized by energizing the magnetizing coil.

  According to the magnetizing method of the multipolar magnet, since the plurality of protruding pieces are magnetized in a state where the magnet material is arranged so that the protruding pieces of the magnetizing yoke face each other, By avoiding the situation where the corresponding part of the magnetizing coil with low accuracy is magnetized, it is possible to magnetize multiple protruding pieces of magnet material using the convex part of the magnetizing yoke with high shape accuracy, It is possible to improve the magnetization accuracy of the multipolar magnet after magnetization.

  In the above multipolar magnet magnetization method, it is preferable that the plurality of protruding pieces of the magnet material are formed so as to protrude from a base portion made of a soft magnetic material. In this case, the base made of a soft magnetic material functions as a back yoke and prevents leakage of magnetic flux generated by energizing the magnetizing coil, thereby increasing the magnetic flux density passing through the protruding piece. It becomes possible to improve the magnetic force in the protruding piece of the multipolar magnet after magnetizing.

  For example, in the magnetizing method of the multipolar magnet, the magnet material has an annular shape. When the magnet material has an annular shape, the shape of the magnetizing coil disposed in the concave portion of the magnetizing yoke is likely to be non-uniform, but a plurality of protruding pieces are opposed to the convex portion of the magnetizing yoke. By magnetizing the plurality of projecting pieces in the arranged state, it is possible to avoid the situation where the corresponding portion of the magnetizing coil with low shape accuracy is magnetized, and to form the convex portion of the magnetized yoke with high shape accuracy. Since the projecting piece of the magnet material can be magnetized by using it, it is possible to improve the magnetization accuracy of the multipolar magnet after magnetization.

  The multipolar magnet of the present invention is magnetized by any one of the above-described magnetization methods. As described above, by magnetizing the multipolar magnet by any of the above-described magnetization methods, the protruding pieces magnetized at the N pole and the protruding pieces magnetized at the S pole are alternately arranged. Since a multipolar magnet in which a magnetic pole portion magnetized in the N pole or S pole and a non-magnetic pole portion not magnetized are arranged at regular intervals can be manufactured, it has a planar shape as in the prior art. Compared to the case of magnetizing the magnet material, it is possible to improve the magnetization accuracy.

  A magnetic encoder according to the present invention includes the above-described multipolar magnet, and a magnetic detection means that is disposed to face the plurality of protruding pieces of the magnet material constituting the multipolar magnet and detects magnetic flux from the protruding pieces. It is characterized by comprising. In this way, by applying a multipolar magnet with improved magnetization accuracy to a magnetic encoder, a more uniform pulse output can be obtained corresponding to a plurality of protruding pieces in the multipolar magnet, and the signal period The accuracy can be improved.

  According to the present invention, since the plurality of protruding pieces are magnetized in a state where the magnet material is arranged so that the plurality of protruding pieces face the convex portion of the magnetizing yoke, the shape accuracy is low. By avoiding the situation where the corresponding part of the coil is magnetized, the projecting piece of the magnet material can be magnetized using the convex part of the magnetized yoke with high shape accuracy. It is possible to improve the magnetization accuracy.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following, the case where the present invention is embodied in a method for magnetizing a multipolar magnet will be described. However, the present invention is not limited to this, and the multipolar magnet that is magnetized by the magnetizing method. As well.

  FIG. 1 is a diagram illustrating a configuration of a magnet material 1 that is magnetized by a magnetization method according to an embodiment. As shown in FIG. 1, the magnet material 1 is provided so as to protrude from a base portion 101 formed of a plate-shaped member having an annular shape and one surface of the base portion 101 (one surface directed to the magnetizing yoke 2 side described later). And a plurality of protruding pieces 102 formed. These protruding pieces 102 are arranged at equal intervals over the entire circumference in the outer peripheral side portion of the base 101. Specifically, it is provided so as to be opposed to the convex portion 203 of the magnetized yoke 2 described later. End surfaces (upper end surfaces shown in FIG. 1) of these protruding pieces 102 are arranged on the same plane, and these end surfaces constitute a mounting surface for the magnetized yoke 2 described later. In addition, between each protrusion piece 102, the recessed part 103 dented from the mounting surface with respect to the magnetizing yoke 2 to the base 101 will be formed.

  In addition, as the magnet raw material 1 applied to the magnetization method according to the present embodiment, for example, Nd—Fe—B-based powder and resin powder as a binder are mixed and press-molded, and further subjected to a curing heat treatment and A so-called neodymium bonded magnet with rust-proof coating is suitably employed, but is not limited to this, and a ferrite magnet, a sintered neodymium magnet, or the like may be employed.

  FIG. 2 is a perspective view of a state in which the magnet material 1 according to the present embodiment is placed on the magnetizing yoke 2. 3 is a cross-sectional view taken along the alternate long and short dash line in FIG. The magnetized yoke 2 used in the method for manufacturing a multipolar magnet according to the present embodiment is formed by machining a soft magnetic material, for example. As shown in FIGS. 2 and 3, the magnetized yoke 2 includes a cylindrical portion 201 having a short cylindrical shape and a fixing portion 202 for fixing the cylindrical portion 201 to a base member or the like. . The fixing portion 202 is formed integrally with the cylindrical portion 201 and is formed in a flange shape at the lower end thereof.

  A plurality of concavo-convex portions are formed on the upper end portion of the cylindrical portion 201 over the entire circumference. The magnet material 1 is placed on the upper surface of the convex portion 203 constituting the concave-convex portion in a state where the plurality of protruding pieces 102 are directed downward. A magnetizing coil 205 is routed around the concave portion 204 constituting the concave-convex portion. The plurality of concavo-convex portions function as tooth profile portions for routing the coil 205. Since the magnetized yoke 2 is formed by machining as described above, the concavo-convex portion formed on the cylindrical portion 201 is formed with a certain shape accuracy. On the other hand, the coil 205 disposed in the concave portion 204 of the concavo-convex portion is subjected to a bending process or the like by manual work or the like, so that the shape accuracy is lower than the shape accuracy of the concavo-convex portion.

  The magnetizing coil 205 is composed of a single coil connected to a magnetizing power supply device (not shown) (for example, a pulse magnetizing power supply device), and the inner peripheral end ( It arrange | positions at the recessed part 204 so that the inner peripheral side edge part of the cylindrical part 201 and an outer peripheral side edge part (outer peripheral side edge part of the cylindrical part 201) may pass alternately. That is, the coil 205 is arranged so that current flows in different directions in the concave portion 204 arranged on the side of the convex portion 203. In this case, as will be described later, the coil 205 is disposed in the recess 204 so as to form a magnetized pattern in which N and S poles are alternately arranged. In addition, in the state arrange | positioned at the recessed part 204, the upper end part of the coil 205 is the state arrange | positioned in the position lower than the upper surface of the convex part 203. FIG.

  FIG. 4 is an enlarged view of a main part in a state where the magnet material 1 according to the present embodiment is placed on the magnetizing yoke 2. As shown in FIG. 4, in a state where the magnet material 1 is placed on the magnetizing yoke 2, the plurality of protruding pieces 102 of the magnet material 1 are respectively disposed to face the convex portions 203. That is, the magnet material 1 is in surface contact with the upper surface of the convex portion 203 by the plurality of protruding pieces 102. In the state of being placed on the convex portion 203, the protruding piece 102 is disposed at a substantially central portion of the convex portion 203 as shown in FIG. 3. In this way, the magnet material 1 is positioned at a position where the plurality of protruding pieces 102 are arranged to face the convex portion 203, and in this state, is temporarily fixed to the magnetizing yoke 2 for the magnetizing process. The configuration for positioning and fixing is not particularly limited.

  In the magnetizing method according to the present embodiment, the magnetizing process is performed by energizing the coil 205 with the magnet material 1 placed on the magnetizing yoke 2 as described above. When the coil 205 is energized, current flows in different directions through the coils 205 arranged in the adjacent recesses 204 as described above. FIG. 5 is a schematic diagram for explaining the direction of current flowing in the coil 205 disposed in the adjacent recess 204. In this case, a large pulse current flows through the coil 205 from the magnetized power supply device at a predetermined timing.

  As shown in FIG. 5, a current that travels to the back side of the paper flows through a coil 205 a that is disposed in a recess 204 a on the left side shown in the figure of a certain protruding piece 102 a, while Assuming that a current traveling forward in the drawing flows through the arranged coil 205b, magnetic fields traveling in the directions of arrows A and B are generated around the coils 205a and 205b, respectively. As a result, a magnetic flux traveling from the upper side to the lower side shown in FIG. 5 is formed on the protruding piece 102a, and its end face is magnetized to the N pole. Similarly, on the protruding pieces 102b and 102c adjacent to the protruding piece 102a, a magnetic flux is generated which proceeds from the lower side to the upper side on the same principle, and the end face is magnetized to the S pole.

  In this case, in the magnet material 1, since the magnetizing process is performed in a state where the protruding piece 102 is placed on the convex portion 203 of the magnetizing yoke 2, the magnetic field generated from the coil 205 is directly above the coil 205. The portion (the portion existing between the protruding pieces 102) is not affected. When the magnet material 1 has a planar shape as in the prior art, a situation may occur in which the magnetic field generated from the coil 205 affects the portion directly above the coil 205 (the magnet material portion disposed in the recess 103). That is, the portion directly above the coil 205 is magnetized with a small amount, and the magnetized portion causes a decrease in magnetization accuracy. According to the magnetization method according to the present embodiment, since the concave portion 103 is formed in the portion that causes a decrease in magnetization accuracy in this way, it is possible to avoid a situation in which the portion directly above the coil 205 is magnetized. Therefore, it becomes possible to improve the magnetization accuracy.

  By performing the magnetization process in this way, the magnet material 1 shown in FIG. 1 is a multipolar magnet 3 in which N poles and S poles are alternately arranged. FIG. 6 is a diagram showing a configuration of the multipolar magnet 3 magnetized by the magnetization method according to the present embodiment. 6 shows the protruding pieces 102a to 102c used in FIG. 5 for convenience of explanation. As shown in FIG. 6, in the multipolar magnet 3, the protruding pieces 102 magnetized to the N pole and the protruding pieces 102 magnetized to the S pole are alternately arranged. As described above, since the portion corresponding to the recess 103 is not magnetized, the magnetic pole portion magnetized in the N pole and the S pole and the non-magnetized magnetic pole portion are arranged at regular intervals. Yes.

  As described above, according to the method for magnetizing a multipolar magnet according to the present embodiment, a plurality of protrusions are provided in a state in which the magnet material 1 is arranged so that the protrusions 102 face the convex portions 203 of the magnetizing yoke 2. Since the piece 102 is magnetized, it is possible to avoid the situation in which the corresponding portion (directly above portion) of the coil 205 having low shape accuracy is magnetized, and the convex portion 203 of the magnetized yoke 2 having high shape accuracy. Since the plurality of projecting pieces 102 of the magnet material 1 can be magnetized, it is possible to improve the magnetization accuracy of the multipolar magnet 3 after magnetization.

  And in the multipolar magnet 3 magnetized by the magnetizing method of the multipolar magnet according to the present embodiment as described above, the protruding piece 102 magnetized to the N pole and the protruding magnetized to the S pole Since the pieces 102 are alternately arranged and the magnetic pole portions magnetized in the N or S poles and the non-magnetic pole portions not magnetized are arranged at a constant interval, the planar shape can be changed as in the conventional case. Compared with the case of magnetizing the magnet material, the magnetization accuracy can be improved.

  By the way, the multipolar magnet 3 with improved magnetization accuracy is suitably used for a magnetic encoder, for example. In such a magnetic encoder, for example, as shown in FIG. 7, the magnetic flux from the protruding piece 102 is detected at a position spaced apart from the protruding piece 102 constituting the magnetic pole part of the multipolar magnet 3 by a certain distance. It is conceivable to arrange the magnetic detection sensors 4 so as to face each other. In this case, it is preferable to arrange the multipolar magnet 3 so that the plurality of protruding pieces 102 rotate and move at a position separated from the magnetic detection sensor 4 by a certain distance.

  In such a magnetic encoder, for example, the multi-pole magnet 3 is fixed to an operation knob that receives an operation from a user, while the magnetic detection sensor 4 having a GMR (Giant Magneto Resistance) element is used as the magnetic detection element. It is fixed inside. Then, magnetic flux from the plurality of protruding pieces 102 of the multipolar magnet 3 fixed to the operation knob is applied to the magnetic detection sensor 4. Thereby, the change in the electric resistance value of the magnetic detection sensor 4 is caused by the direction of the magnetic flux from the protruding piece 102, and the rotation amount of the operation knob is detected from the output signal (voltage signal) of the magnetic detection sensor 4. Conceivable.

In this case, the magnetic detection sensor 4 that outputs an output signal in response to the magnetic flux from the plurality of protruding pieces 102 of the multipolar magnet 3 has, as a basic configuration, an antiferromagnetic layer, a pinned layer, an intermediate layer, and a free layer. A layer is formed by laminating on a substrate (not shown), and is configured as a sensor including a GMR element using a giant magnetoresistive effect. In order for the GMR element included in the magnetic detection sensor 4 to exhibit a giant magnetoresistance effect, for example, the antiferromagnetic layer is an α-Fe ₂ O ₃ layer, the pinned layer is a NiFe layer, the intermediate layer is a Cu layer, free The layer is preferably formed of a NiFe layer, but is not limited thereto, and any layer may be used as long as it exhibits a magnetoresistive effect. Further, the GMR element provided in the magnetic detection sensor 4 is not limited to the one having the above laminated structure as long as it exhibits a magnetoresistive effect.

  Thus, when the multipolar magnet 3 according to the present embodiment is applied to a magnetic encoder, a more uniform pulse output can be obtained corresponding to the plurality of protruding pieces 102 in the multipolar magnet 3, It is possible to improve the signal cycle accuracy.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously. In the above-described embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  For example, in the method of magnetizing a multipolar magnet according to the above-described embodiment, it has been described that the press-molded magnet material 1 is used. However, the present invention is not limited to this. For example, as shown in FIG. 8, a convex member 502 constituting the protruding piece 102 is formed by outsert molding on a plate-like member (outsert member) 501 having an annular shape made of a soft magnetic material. You may make it do. When such a magnet material 1 is used, if the magnetizing process is performed in a state where the magnet material 1 is placed on the magnetizing yoke 2, the plate member 501 functions as a back yoke, and the magnetic flux generated by energizing the coil 205 is generated. Since the magnetic flux density passing through the convex member 502 can be increased while preventing the leakage of the magnetic field, it is possible to improve the magnetic force in the protruding piece 102 in the multipolar magnet 3 after magnetization.

  Moreover, in the said embodiment, although the case where the magnet raw material 1 has an annular shape was demonstrated, about the shape of the magnet raw material 1, it is not limited to this and can be changed suitably. For example, you may apply the magnet raw material 1 which has the elongate shape in which the several protrusion piece 102 was arranged in parallel with the longitudinal direction to the magnetization method of the multipolar magnet which concerns on this Embodiment. Even when such a magnet material 1 is used, it is possible to obtain the same effects as in the above embodiment.

It is a figure which shows the structure of the magnet raw material magnetized by the magnetization method which concerns on this Embodiment. It is a perspective view of the state by which the magnet raw material which concerns on the said embodiment was mounted in the magnetizing yoke. It is sectional drawing in the dashed-dotted line shown in FIG. It is a principal part enlarged view of the state by which the magnet raw material which concerns on the said embodiment was mounted in the magnetizing yoke. In the magnetized yoke according to the above embodiment, it is a schematic diagram for explaining the direction of a current flowing in a coil arranged in an adjacent recess. It is a figure which shows the structure of the multipolar magnet magnetized by the magnetization method which concerns on the said embodiment. It is a principal part enlarged view of the magnetic encoder to which the multipolar magnet which concerns on the said embodiment is applied. It is a figure which shows the modification of the magnet raw material which concerns on the said embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnet material 101 Base part 102 Protruding piece 103 Concave part 2 Magnetization yoke 201 Cylindrical part 202 Fixing part 203 Convex part 204 Concave part 205 Coil 3 Multipolar magnet 4 Magnetic detection sensor 501 Plate-like member 502 Convex-like member

Claims (5)

A magnetizing yoke having a plurality of concavo-convex portions on the magnet material side and in which a magnetizing coil is routed so as to form a magnetization pattern in which N poles and S poles are alternately arranged in the concave portions of the concavo-convex portions, A magnetizing method of a multi-pole magnet for magnetizing by contacting the magnet material having a plurality of protruding pieces corresponding to the convex portions of the part,
A multi-pole magnet, wherein the plurality of projecting pieces are disposed opposite to the convex portions of the uneven portion of the magnetizing yoke, and the plurality of projecting pieces are magnetized by energizing the magnetizing coil. Magnetization method.   2. The method of magnetizing a multipolar magnet according to claim 1, wherein the plurality of protruding pieces of the magnet material are formed to protrude from a base portion made of a soft magnetic material.   The method for magnetizing a multipolar magnet according to claim 1, wherein the magnet material has an annular shape.   A multipolar magnet that is magnetized by the magnetizing method according to any one of claims 1 to 3.   5. The multipolar magnet according to claim 4, and a magnetism detecting means that is arranged to face the plurality of projecting pieces in the magnet material constituting the multipolar magnet and detects a magnetic flux from the projecting pieces. Magnetic encoder.

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