JP4508019B2 - Anisotropic bond sheet magnet and manufacturing apparatus thereof - Google Patents

Description

  The present invention relates to an anisotropic bond sheet magnet manufacturing apparatus having high magnetic properties and thermal stability, an anisotropic bond sheet magnet manufactured using the same, and a permanent magnet motor equipped with the anisotropic bond sheet magnet. .

  Bond magnets have a feature that they can be produced with high dimensional accuracy even in special shapes such as an annular shape, an arc shape, and a thin shape without cracks or chips. For this reason, ring-shaped bonded magnets are frequently used in home appliances, electrical equipment, and information motors in recent years.

  However, recent developments in home appliances, electrical equipment, information equipment, and the like have been remarkable, and motors used in such equipment are also required to be smaller, lighter, higher in output, and more efficient in accordance with higher performance of equipment.

  In response to this demand, further improvement in magnetic properties of bond magnets mounted on these motors is also demanded. As a means for improving the magnetic properties, it is conceivable to use magnetically anisotropic magnet powder that can obtain high magnetic properties in a specific direction.

However, anisotropic magnet powder has a problem with respect to thermal stability. Magnetically anisotropic magnet powders include anisotropic Nd ₂ Fe ₁₄ B magnet powders obtained by grinding a bulk obtained by mechanical orientation by hot upsetting, Ga, Zr Nd—Fe (Co) —B based alloy ingot to which elements such as H, Hf, etc. are added is heat-treated in hydrogen, and Nd—Fe (Co) —B based hydrogenation (Hydrogenation), phase at 650 to 1000 ° C. There are Nd ₂ Fe ₁₄ B-based magnet powders anisotropicized by a so-called HDDR process, such as decomposition, dehydrogenation, and recombination.

Such anisotropic Nd ₂ Fe ₁₄ B-based magnet powder has an Nd-Rich phase at the crystal grain boundary and is likely to cause permanent demagnetization due to grain boundary corrosion, and the degree of orientation of the magnet is poor. Since it is perfect, the squareness of the demagnetization curve of the magnet is poor, and there is a drawback that it is easily affected by heat.

  As one of the means for solving the problem, an oriented magnet in which the orientation of the magnet powder is oriented for each pole has been proposed in order to increase the permeance of the magnet and increase the surface magnetic flux density and the thermal stability. As means for producing an oriented magnet, there are (1) a method of orienting magnet powder using a magnetic field generated by a permanent magnet, and (2) a method of orienting magnet powder using a magnetic field generated by an electromagnet.

  For example, FIG. 4 shows the relationship between the orientation magnetic field and the orientation rate of a product obtained by molding a resin composition for bonded magnets mainly composed of anisotropic SmFeN magnet powder, NdFeB magnet powder and thermoplastic elastomer at a molding temperature of 150 ° C. .

  It is shown that the magnetic field required for complete orientation is 1.5T or more. By the way, in the method (1) of using the magnetic field generated by the permanent magnet and orienting the magnet powder, the permanent magnet is thermally demagnetized at a high temperature such as 150 ° C., and the molding area is as high as 1.5 T. It is difficult to generate a magnetic field.

  On the other hand, in the method of orienting magnet powder using the magnetic field generated by the electromagnet (2), a high magnetic field exceeding 1.5 T can be generated (see, for example, Patent Document 1).

  A magnet produced by a conventional method as disclosed in Patent Document 1 is oriented in the in-plane direction of the magnet sheet (herein referred to as plane orientation).

  FIG.5 (c) is the perspective view which showed the anisotropic bond sheet magnet and the magnet powder orientation direction. In the figure, the orientation direction 108 of the magnet powder of the anisotropic bond sheet magnet 107 is linearly oriented in the in-plane direction of the magnet.

  FIG. 6 is a schematic diagram in which such a plane-oriented magnet is arranged in the shape of a rotor of a motor. As shown in the drawing, the anisotropic bond sheet magnet 107 is formed into an annular shape to constitute a permanent magnet rotor, and a motor coil 118 is wound around a stator core 117 of the motor.

The magnetic flux 116 generated from the anisotropic bond sheet magnet 107 leaks not only in the direction of the stator core of the motor effective for the motor torque but also in the opposite direction of the motor stator core that does not contribute to the motor torque. There is a problem that the amount of magnetic flux that is effectively utilized decreases, and the magnet characteristics cannot be fully utilized.
JP 2004-55992 A

  The present invention solves the above-described conventional problems, and in an oriented magnet that uses anisotropic rare earth magnet powder and can improve thermal stability, it is in a direction that effectively works on motor torque. Providing manufacturing equipment that produces anisotropic bond sheet magnets with low magnetic flux leakage, and motors with high thermal stability that are smaller, lighter, higher output, more efficient, and equipped with the produced anisotropic bond sheet magnets It is to be.

In order to solve the above-mentioned problems, the present invention provides a resin composition for bonded magnets by embedding a plurality of soft magnetic bodies at equal intervals in the direction of the magnetic field created by the electromagnet for magnet powder orientation in the lower punch. Due to the magnetic field created by the magnet powder orientation electromagnet in the magnetic field generating region to be filled, the magnetic force of the parallel component is increased in the upper part between the soft magnetic materials, and the perpendicular component is increased in the upper part of the soft magnetic material. An anisotropic bond sheet magnet manufacturing apparatus for generating an anisotropic bond sheet magnet by generating a magnetic field flow and orienting and molding the bond magnet resin composition is provided.

  The anisotropic bonded sheet magnet manufacturing apparatus of the present invention can be oriented so that the magnetic force in the parallel direction component of the sheet surface is between the magnetic poles and the magnetic component in the perpendicular direction component of the sheet surface is large at the magnetic pole end. It is possible to provide an anisotropic bond sheet magnet with less leakage of magnetic flux in the direction of effective working.

Has as one pair of the magnetic powder oriented electromagnet punch on the non-magnetic material disposed between the electromagnets, the lower punch, and the molding die consisting of the placed die to guide the upper and lower punches, said magnet The powder orientation electromagnet is disposed outside the upper punch, the lower punch, and the die, and a plurality of soft magnetic materials are embedded in the lower punch at equal intervals in the direction of the magnetic field created by the magnet powder orientation electromagnet. By the magnetic field generated by the electromagnet for magnet powder orientation in the magnetic field generating region filled with the resin composition for bonded magnets,
A magnetic field flow is generated on the upper portion of the soft magnetic material of the parallel direction component so as to increase the magnetic force of the perpendicular component, and the resin composition for the bond magnet is oriented and molded, and an anisotropic bond sheet is formed. It is an anisotropic bond sheet magnet manufacturing apparatus which produces | generates a magnet.

  The magnet produced by this anisotropic bond sheet magnet device is oriented so that the magnetic force of the parallel component of the sheet surface is large between the magnetic poles, and the perpendicular component of the sheet surface is large at the magnetic pole end (here, (Referred to as polar orientation), there is little leakage of magnetic flux in the direction that effectively works on the motor torque.

  In addition, permanent magnet motors equipped with anisotropic bond sheet magnets can provide small, lightweight, high output, high efficiency and high thermal stability motors because there is little leakage of magnetic flux in the direction that works effectively for motor torque. .

  Examples of the present invention will be described below.

Example 1
The following examples illustrate the present invention in more detail.

  Anisotropic Sm—Fe—N magnet powder with an average particle diameter of 2 to 3 μm 98 wt. % And orthocresol novolac type epoxy resin 2 wt. A resin solution in which% is dissolved in an organic solvent is wet-mixed. Further, an anisotropic Nd—Fe—B magnet powder having an average particle diameter of about 100 μm, 99 wt. % And orthocresol novolac type epoxy resin 1 wt. A resin solution in which% is dissolved in an organic solvent is wet-mixed.

  After the wet mixing, the above two kinds of mixtures are dried at 80 ° C. for 60 minutes to volatilize the organic solvent component to obtain a mixture A and a mixture B.

  Next, mixture A 58 wt. % And Mixture B 39 wt. % And a polyamide elastomer powder of 3 wt. % Is dry-mixed and pelletized with an extruder. The pellets were pulverized to 350 μm or less, and finally a latent epoxy curing agent having an average particle size of 5 to 10 μm was added to the epoxy resin at 30 wt. % Dry-mixing to obtain a bonded magnet resin composition.

FIG. 1A is a cross-sectional view of the anisotropic bonded sheet magnet manufacturing apparatus of the first embodiment. As shown in the figure, it has a pair of magnet powder orientation electromagnets 1 and a non-magnetic material upper punch 2, die 3 and lower punch 4 disposed between the electromagnets 1. A plurality of soft magnetic bodies 5 are embedded at equal intervals in the direction of the magnetic field generated by the powder orientation electromagnet 1, and a magnetic field is generated in the magnetic field generation region 9.

  FIG. 1B is a schematic diagram in which the lower punch 4 and the magnetic field generation region of Example 1 are enlarged. As shown in the figure, a unidirectional magnetic field created by the lower punch 4 by an electromagnet for magnet powder orientation is distorted by a soft magnetic material 5 to generate an orientation magnetic field 6.

  That is, with respect to the magnetic field generated by the magnet powder orientation electromagnet 1 in the magnetic field generating region 9 filled with the resin composition for bonded magnets, the upper part between the soft magnetic bodies 5 has an upper portion of the soft magnetic body 5 in the parallel direction component. The magnetic field flow is generated so that the magnetic force of the perpendicular component is large.

  As a manufacturing method, the resin composition for bonded magnets is filled in the magnetic field generating region 9 of the anisotropic bonded sheet magnet manufacturing apparatus at a molding temperature of 150 ° C. and the generated magnetic field of the magnet powder orientation electromagnet of 1.5 T. When compression molding is performed at 50 MPa while generating a magnetic field flow in the manufacturing apparatus, the anisotropic bond before magnetization in which the orientation direction 8 of the magnet powder is pole-oriented as shown in the perspective view of FIG. A sheet magnet 7 is obtained.

  FIG. 2 is a cross-sectional view showing the main part of the magnetizing apparatus. As shown in the figure, the magnetizing device is composed of a magnetizing yoke 12, a magnetizing coil 13, and a nonmagnetic material 14, and generates a magnetizing magnetic field 15.

  Here, the oriented anisotropic bond sheet magnet 7 is magnetized under the conditions of a magnetizing voltage of 1800 V, a capacitor capacity of 1000 μF, and a magnetizing current of 16 kA, so that it is magnetized in the orientation direction 8 of FIG. The magnetized anisotropic bond sheet magnet 7 is completed.

  The surface magnetic flux density of the anisotropic bond sheet magnet after magnetization was measured with a gauss meter (digital gauss meter, Japan Electromagnetic Instrument Model 501). Table 1 shows the maximum value of the surface magnetic flux density and magnetization for 60 minutes at 100 ° C. The demagnetization rate after leaving the subsequent magnet alone is shown. Magnetization may be performed after the sheet is deformed into an annular shape.

  In addition, when the anisotropic bond sheet magnet produced with the said manufacturing method is made into the following permanent magnet mounting motors, the performance improvement of a motor will be attained.

  Here, an example used for a motor is shown. FIG. 3 is a schematic diagram in which pole-oriented magnets are annularly arranged on a motor rotor. As shown in the figure, the orientation direction 8 of the magnet powder of the anisotropic bond sheet magnet 7 is oriented around the entire circumference in an arc shape on the magnet sheet. The oriented anisotropic bond sheet magnet 7 constitutes an annular permanent magnet rotor. The stator core 17 of the motor is wound with a stator coil 18. A motor is constituted by these combinations. The magnetic flux 16 generated from the anisotropic bond sheet magnet 7 is generated in the direction of the stator core 17 of the motor effective for the motor torque, and there is little leakage of the magnetic flux in the opposite direction. More than 6 plane oriented magnets.

(Comparative Example 1)
By the method shown in Example 1, the resin composition for bonded magnets of Comparative Example 1 is prepared.

  FIG. 5A is a cross-sectional view of the anisotropic bonded sheet magnet manufacturing apparatus of Comparative Example 1. FIG. As shown in the figure, it has a pair of magnet powder orientation electromagnets 101, a nonmagnetic material upper punch 102, a die 103, and a lower punch 104 disposed between the electromagnets 101, and a magnetic field is generated in the magnetic field generation region 109. Generate.

  FIG. 5B is a schematic diagram in which the lower punch and the magnetic field generation region in Comparative Example 1 are enlarged. As shown in the figure, a unidirectional orientation magnetic field 106 created by the magnet powder orientation electromagnet 101 is generated on the lower punch 104.

  The manufacturing method is the same as in Example 1 except that the molding temperature is 150 ° C. and the magnetic field generated by the electromagnet for magnet powder orientation is 1.5T. , And an anisotropic bonded sheet magnet 107 before magnetization as shown in the perspective view of FIG. 5C is obtained by compressing and orienting at 50 MPa while generating a magnetic field flow in this manufacturing apparatus. This is because magnetic powders are arranged and shaped following the orientation magnetic field 106, and therefore the orientation direction 108 of the magnet powder inside the anisotropic bond sheet magnet 107 is parallel to the sheet surface and is in a plane orientation.

  The oriented anisotropic bond sheet magnet 107 is magnetized by the magnetizing apparatus shown in FIG. 3 in the same manner as in Example 1, so that the anisotropic bond sheet magnet 107 shown in FIG. An anisotropic bond sheet magnet 107 magnetized in the orientation direction 108 is completed.

  The surface magnetic flux density of the anisotropic bonded sheet magnet after magnetization was measured with a gauss meter, and Table 1 shows the maximum value of the surface magnetic flux density and the demagnetization factor after leaving the magnet alone after magnetizing for 60 minutes at 100 ° C. Indicates.

  Moreover, when the permanent magnet type | mold motor which forms a surface magnet type | mold rotor as an annular magnet similarly to Example 1 is comprised, it will become FIG.

  As can be seen from the results in Table 1, the magnetic flux density is higher by about 40% in Example 1 than in Comparative Example 1 because there is less leakage of magnetic flux in the direction that works effectively on the motor torque. Further, as shown in FIG. 1 (c), since the polar orientation magnetic flux of Example 1 is arcuate, the surface orientation magnetic flux of Comparative Example 1 as shown in FIG. In Example 1, the distance between the magnetic poles is longer, the demagnetizing field is smaller, and the influence of the demagnetizing field when heat is applied is less, so the thermal demagnetization factor is about 40% lower.

  When the anisotropic bond sheet magnet manufactured using the manufacturing method and manufacturing apparatus of the anisotropic bond sheet magnet of the present invention is used, a small, high output and high efficiency motor having high thermal stability can be manufactured.

(A) is sectional drawing of the manufacturing apparatus of the anisotropic bond sheet magnet of Example 1, (b) is the schematic diagram which expanded the lower punch and magnetic field generation | occurrence | production area | region of Example 1, (c) is different from Example 1. Perspective view showing the direction of orientation of the anisotropic bond sheet magnet and magnet powder Sectional drawing which shows the principal part of a magnetizing apparatus Schematic diagram of pole-oriented magnets arranged in a ring on the motor rotor Characteristic diagram showing the relationship between general orientation magnetic field and orientation rate (A) is sectional drawing of the manufacturing apparatus of the anisotropic bond sheet magnet of the comparative example 1, (b) is the schematic diagram which expanded the lower punch and the magnetic field generation | occurrence | production area | region of the comparative example 1, (c) is different in the comparative example 1. Perspective view showing the direction of orientation of magnetic bond sheet magnet and magnet powder Schematic diagram of conventional plane-oriented magnets arranged in a ring on the motor rotor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnet powder orientation electromagnet 2 Upper punch 3 Dies 4 Lower punch 5 Soft magnetic material 6 Orientation magnetic field 7 Anisotropic bond sheet magnet 8 Orientation direction of magnet powder 9 Magnetic field generation region 12 Magnetization yoke 13 Magnetization coil 14 Nonmagnetic Body 15 Magnetized magnetic field 16 Magnetic flux 17 Stator core of motor 18 Stator coil

Claims (3)

A pair of magnet powder orientation electromagnets, a non-magnetic material upper punch disposed between the electromagnets, a lower punch, and a molding die including a die disposed so as to guide the upper and lower punches;
The magnet powder orientation electromagnet is disposed outside the upper punch, the lower punch, and the die, and a plurality of soft magnetic materials are arranged at equal intervals in the direction of the magnetic field created by the magnet powder orientation electromagnet on the lower punch. By embedding, a magnetic field generated by the electromagnet for magnet powder orientation in a magnetic field generating region filled with a resin composition for bonded magnets, the upper part between the soft magnetic bodies is parallel to the upper part of the soft magnetic body. An anisotropic bond sheet magnet that generates an anisotropic bond sheet magnet by generating a flow of a magnetic field so as to increase the magnetic force of a component in a perpendicular direction, and orienting and molding the resin composition for the bond magnet. Manufacturing equipment. An anisotropic bond sheet magnet made by the anisotropic bond sheet manufacturing apparatus according to claim 1. A permanent magnet motor equipped with the anisotropic bond sheet magnet according to claim 2.

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