JPH0661036A - Anisotropic magnet of side orientation - Google Patents

Abstract

PURPOSE:To improve the characteristics of a permanent magnet by orienting the axes of easy-magnetization of the constituent particles of the magnet substantially toward its surface of action from its side edges. CONSTITUTION:A permanent magnet has a surface of action and adjacent edges. The axes of easy magnetization of constituent particles of the magnet are oriented along the magnetic lines of force from the adjacent edges to the surface of action. Lateral orientation is applied to a disc magnet by magnetization of particles along the axis of easy magnetization. When the magnet is attached to a ferromagnetic body, magnetic lines of force other than from the surface of action are those from the sides; that is, they are much fewer than in the case of a magnet of axial or converging orientation. Therefore, it is possible to enhance the flux at the surface of action of the magnet and increase the reach of magnetic lines of force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laterally oriented anisotropic magnet, and more particularly to improving the surface magnetic field of the working surface after magnetization. INDUSTRIAL APPLICABILITY The present invention can be universally applied to applications requiring a strong surface magnetic field and a deep magnetic field line arrival length. For example, by applying to various shapes, magnets for signal generation, magnets for axial gap motors, magnets for magnetrons, magnets for length measuring machines, magnets for precision motors, etc., fixed display magnets for paper, sheets, etc. Can be widely used as a magnet for health promotion equipment.

[0002]

2. Description of the Related Art Conventionally, rare earth-based or ferrite-based sintered magnets and synthetic resin magnets have been used as magnets used for the above purposes. In both cases, the orientation direction of the magnetic powder is shown in FIG. As shown, it is in the thickness direction, and therefore the quality of magnetic properties was determined by the type of raw material used and the content of magnetic powder. In order to improve this point, an anisotropic permanent magnet whose magnetic characteristics are improved by devising the orientation direction of magnetic powder was proposed in Japanese Patent Publication No. 63-59243. This magnet, as shown in FIG.
The direction of the easy axis of magnetization is focused and oriented from the non-acting surface (all surfaces other than the acting surface) to the acting surface. This magnet allows the magnetic flux density per unit area (or per unit line segment) Magnetic flux density) can be made larger than before.

However, even in the magnet having the focusing orientation as described above, a particularly high surface magnetic field peak value is required as in the case of a hollow disk-shaped magnet for signal generation which is sensed by a Hall element. In some applications, it was difficult to say that sufficient characteristics could be obtained. Further, even when it is used for a length measuring machine or a small precision motor, a more excellent surface magnetic field is required to improve its accuracy.

[0004]

SUMMARY OF THE INVENTION The present invention advantageously solves the above problems and proposes an anisotropic magnet that can obtain a large peak value of the surface magnetic field without using a particularly expensive material. With the goal.

[0005]

First, the process of clarifying the present invention will be described. Now, the inventors of the present invention have shown that the conventional magnet having the magnetic powder orientation (hereinafter referred to as axial orientation) along the plate thickness direction shown in FIG. In order to elucidate the reason why a magnet focused toward (to be referred to as "focusing orientation" hereinafter) is superior in magnetic characteristics,
As a result of earnest studies, it has been thought that the reason may be the number of magnetic lines of force wasted from the non-acting surface and the magnetic path length when the magnet is attracted. Therefore, in order to reduce the number of magnetic lines of force that are unnecessarily radiated at the time of adsorption and the length of its magnetic path, the emission of magnetic lines of force from the surface facing the working surface is eliminated, and the radiation of magnetic flux from the surface other than the working surface is limited to the side surface. However, the unexpected result was obtained regarding the improvement of the magnetic properties. The present invention is based on the above findings.

That is, the gist of the present invention is as follows. 1. A permanent magnet having a working surface and a side surface adjacent to the working surface, wherein the easy axis of magnetization of magnetic powder particles constituting the magnet is substantially oriented along a magnetic line of force extending from the side surface to the working surface. Anisotropic magnet. 2. The side-oriented anisotropic magnet according to the above 1, wherein the magnet has a flat plate shape. 3. The side-oriented anisotropic magnet according to the above 1, wherein the magnet has a hollow disk shape. 4. The side-oriented anisotropic magnet according to the above 1, wherein the magnet has an annular shape. 5. The side-oriented anisotropic magnet according to the above 1, wherein the magnet has a long rod shape. 6. The side-oriented anisotropic magnet according to the above 2, 3, 4 or 5, having working surfaces on opposite surfaces. 7. 7. The laterally oriented anisotropic magnet according to the above 2, 3, 4, 5 or 6, which has a plurality of intermittent working areas on the working surface.

The present invention will be described in detail below. Figure 3
In (a), the lateral orientation according to the present invention is applied to a plate-shaped magnet, particularly a disk-shaped magnet, and this magnet is magnetized along the orientation direction of the easy axis of magnetization of magnetic powder particles and then adsorbed on a ferromagnetic material. The radiating state of the magnetic field lines is shown. As is clear from the figure, the radiation of the magnetic field lines from the surface other than the working surface is only on the side surface, which is significantly reduced as compared with the conventional axial orientation type magnet and focusing orientation type magnet, and therefore the magnetic flux density is greatly reduced. That's a big improvement.

Further, FIG. 1 (b), FIG. 2 (b) and FIG.
(B) shows the surface magnetic field patterns on the working surfaces of the conventional axial orientation type magnet, the focusing orientation type magnet and the side surface orientation type magnet according to the present invention, respectively. Therefore, a higher surface magnetic field than the conventional one can be obtained and a deep magnetic field line arrival length can be obtained.

Although the flat magnet has been mainly described above, the present invention can be used in various other shapes depending on the application. Hereinafter, a magnet having a typical shape will be described. ・ Centered disk-shaped magnet The centered disk-shaped magnet is used for applications such as signal generating magnets, and in such applications, the required action area or required action width is the signal between the Hall element, which is the magnetic receiving element. It is required that the size of the device is as small as the size of the device, and the peak value of the surface magnetic field on the effective surface is as large as possible.

However, in the conventional hollow disc-shaped magnet for signal generation, as shown in a representative example of FIG. 4, the easy axis of magnetization of the magnetic powder particles is simply oriented in the thickness direction of the disc. The surface magnetic field peak value is small, and therefore, in order to improve the signal accuracy, use a sensitive and expensive magnet-receiving element such as a Hall element, or make the gap between the magnet-acting surface and the magnet-receiving element extremely small. Had to do. To reduce the gap between the magnet acting surface and the magnetic field receiving element, it is necessary to minimize the thickness tolerance of the magnet and set the smoothness to an extremely good level. I didn't get it. Further, depending on the case, it is necessary to control the thickness tolerance and smoothness by cutting or / and polishing the working surface, which causes problems in both workability and cost. Therefore, the area (width) of such magnet
This magnet is a magnet that effectively utilizes the magnetic field, and significantly improves the peak value of the surface magnetic field on the effective operating surface, which may be substantially narrow.

That is, in this magnet, in a hollow disk-shaped magnet having one of the front and back surfaces as the working surface, the orientation direction of the easy axis of magnetization of the magnetic powder particles of the disk-shaped magnet is changed from the inner surface to the outer surface. It is focused on the central ring region of. By adopting such a side-focusing orientation, as shown in FIG.
As shown in (a) and (b), the required action area or the required action width can be reduced. Further, as is clear from comparing FIGS. 4 and 5, there is a wasteful magnetic flux in the conventional magnet shown in FIG.
In the invention magnet shown in FIG. 5, all the magnetic fluxes are focused and oriented on the substantially working surface, so that a higher surface magnetic field peak value can be obtained.

Toroidal magnet Here, the term "toroidal magnet" mainly means a cylindrical or ring-shaped magnet. Now, this toroidal magnet is also used for applications such as signal generating magnets, but conventionally, as shown in FIG. 6, the easy axis of magnetization of magnetic powder particles is simply oriented in the thickness direction of the annulus, that is, the radial direction. However, a large peak value of the surface magnetic field could not be obtained. Moreover, productivity cannot be expected to improve due to precision molding, and when controlling the outer diameter tolerance by cutting or / and polishing the working orbiting surface, there were problems in terms of workability and cost. This is similar to the case of the punched disk magnet.

Therefore, in this annular magnet, for example, when the inner peripheral surface or the outer peripheral surface of the annular ring is used as the working surface, the structure shown in FIG.
As shown in (a) and (b), the orientation direction of the easy axis of magnetization of the magnetic powder particles of the annular magnet is changed from the both end surfaces (upper and lower surfaces) of the annular ring to the center of the inner circumferential surface or the outer circumferential surface which is the working surface. Focus on the annulus region. As is clear from comparison between FIG. 6 and FIG. 7, in the annular magnet according to the present invention, the required area (width) of the working surface can be reduced, and all the magnetic flux is focused on the working surface. Therefore, a higher surface magnetic field peak value can be obtained.

Long bar-shaped magnet This long bar-shaped magnet is used for applications requiring a long property in which the magnet working surface is elongated and elongated, for example, magnets for length measuring machines and magnets for rotors of small precision motors. It is particularly suitable. In the conventional magnet, as shown in FIG. 8 (a), the easy axis of magnetization of the magnetic powder particles was merely oriented in the thickness direction, so that only a small surface magnetic field peak value was obtained. In this respect, according to the present invention, as shown in FIG. 9A, if the easy axis of magnetization of the magnetic powder particles of the long magnet is oriented along the magnetic lines of force extending from both side surfaces to the working surface (upper surface), FIG. As shown in (b), all the magnetic flux can be focused on the substantially working surface, resulting in FIG. 9 (c).
Thus, a high surface magnetic field peak value can be obtained.

Further, in this long rod-shaped magnet, as shown in FIG. 10 (a), both opposing short sides of the rectangular cross section can be set as the working area. In this case, the end regions of both long sides are As a side surface, the easy axis of magnetization of the magnetic powder particles is oriented along the magnetic lines of force directed to the end region working area (both short sides).
That is, in a long magnet in which a working region formed in one or a plurality of regions of a contour line in a cross section crossing the longitudinal direction (hereinafter simply referred to as a cross section) is connected in the longitudinal direction, the easy axis of magnetization of the magnetic powder particles in the cross section is The desired effect can be obtained by orienting along the magnetic lines of force from both sides of the working area toward the working area. In addition, in such a long rod-shaped magnet, the application can be further expanded by adopting a flexible synthetic resin material as the magnet material.

Although the long magnet has been mainly described above in the case of a rectangular cross section, the shape of the cross section is not limited to this case, as shown in FIGS. 11 (a) to 11 (i). It may have various sectional shapes such as a trapezoid, a triangle, a polygon, a circle, or a semicircle. The point is that the orientation direction of the magnetic powder particles is focused on one or a plurality of regions of the contour line in the cross section of the long magnet. It suffices to form a working area that is continuous and this working area is continuous or intermittent in the longitudinal direction.

Also, with respect to magnets having a shape other than the long rod shape, both surfaces facing each other can be used as working surfaces depending on the application. 12 (a), (b), and (c) show the orientation of magnetic powder particles when the upper and lower surfaces of the disk-shaped magnet, the upper and lower surfaces of the hollow disk-shaped magnet, and the inner and outer peripheral surfaces of the annular magnet are used as the working surfaces, respectively. Indicates the status.

Further, in the present invention, the working area does not necessarily have to be continuous and may be intermittent.
For example, in a long magnet, in the longitudinal direction of the working surface,
The magnetic pole part that defines the orientation region of the magnetic powder particles is provided intermittently,
The easy axis of magnetization of the magnetic particles in each orientation region is focused and oriented from the side surface region of the magnetic pole portion toward the magnetic pole portion. Although such a magnet is not particularly limited in its use, it is particularly suitable for use in signal generation.

FIG. 13 (a) is a perspective view showing the case where the intermittent magnetic pole portion is applied to a long magnet, and FIGS. 13 (b) and 13 (c).
Shows the orientation states of the easy axis of magnetization of the magnetic particles in the longitudinal section and the width section of the long magnet, respectively.
The longitudinal cross section of FIG. 7B has a focusing orientation, while the cross section of FIG. As shown in FIG. 13, in this magnet, the orientation regions of the magnetic powder are partitioned at a predetermined interval in the longitudinal direction of the magnet, and in each orientation region, the easy axis of magnetization of the magnetic powder particles is set to the working surface side in the longitudinal direction. With respect to the magnetic pole region having a narrow width and only the central portion in the width direction, the side face is focused from only the side face region toward the magnetic pole portion. Although the focusing magnetic pole width and length on the working surface can be appropriately set according to the purpose, it is desirable that the magnetic pole width and length are narrow in order to increase the peak value of the surface magnetic field.

Next, FIG. 14 (a) shows a surface magnetic field pattern when the magnet having the above magnetic powder orientation is magnetized, and FIG. 14 (b) shows a conventional magnet oriented in the thickness direction. Surface magnetic field patterns when magnetized are shown. As is clear from a comparison of the two figures, the magnet of the present invention not only exhibits a clean mountain shape in the surface magnetic field pattern, but also has a significantly larger surface magnetic field peak value than the conventional magnet.

In such a magnet, the magnetic pole area is not limited to the rectangular shape shown in the figure, but may be circular, elliptical or any other shape, and the magnet shape is not limited to the long magnet. A ring or a cylindrical shape as shown in FIGS. Further, the cross-sectional shape of each magnet in the width direction is not limited to the rectangular shape, and may be appropriately selected from a circular shape, a semicircular shape, etc. according to the purpose of use. Furthermore, as shown in FIGS. 16 (a) and 16 (b), when both opposing surfaces are used as working surfaces, the magnetic pole regions can be formed intermittently.

As described above, the magnet shape is flat, hollow disk-shaped,
The case of the annular shape and the long bar shape has been described, but the shape of the magnet is not limited to this case, and as shown in FIG.
It may be a rectangular parallelepiped as shown in (b), (c) and (d), a polygonal pyramid such as a triangular pyramid or a quadrangular pyramid and a hemispherical cone, or a triangular prism or an elliptic cylinder. , The point is Fig. 18
As shown in (a) and (b), it suffices that the easy axis of magnetization of the magnetic powder particles is oriented so as to focus from the side surface of the magnet to the central region of the working surface.

[0023]

The present invention can be applied to both synthetic resin magnets and sintered magnets. For example, as the magnetic powder in the synthetic resin magnet and the sintered magnet, any conventionally known magnetic powder such as ferrite magnetic powder, alnico magnetic powder, and rare earth magnetic powder such as samarium-cobalt magnetic powder or neodymium-iron-boron magnetic magnet can be used. The average particle size is preferably about 1.5 μm for ferrite and about 5 to 50 μm for others.

As the synthetic resin, any of the conventionally known ones can be used, and typical examples thereof are as follows. Polyamide-based synthetic resins such as polyamide-6 and polyamide-12. A homopolymer or copolymer vinyl-based synthetic resin such as polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polymethylmethacrylate, polystyrene, polyethylene and polypropylene. Synthetic resins such as polyurethane, silicone, polycarbonate, PBT, PET, polyetheretherketone, PPS, chlorinated polyethylene and hypalon. Rubbers such as propylene, neoprene, styrene butadiene and acrylonitrile butadiene. Epoxy resin. Phenolic synthetic resin. Furthermore, the mixing ratio of the magnetic powder and the synthetic resin that is the binder depends on the application, but in general, the magnetic powder has a volume percentage of 40-
It is desirable to set it to about 70 vol%.

In addition, it goes without saying that appropriate amounts of conventionally used plasticizers, antioxidants, surface treatment agents and the like can be used according to the purpose. Particularly, a plasticizer is effective in imparting flexibility, and examples of such a plasticizer include dioctylputarate (DOP) and dibutadiputarate (DB).
A phthalate ester-based plasticizer such as P), an adipic acid-based plasticizer such as dioctel adipate (DOA), or a polymer-based plasticizer typified by a polyester-based resin is suitable.

Next, a magnetic circuit device suitable for realizing the magnetic powder orientation according to the present invention and a molding die having the magnetic circuit device will be described. First, FIGS. 19 (a) to 19 (c) schematically show a magnetic circuit device suitable for making a disk-shaped magnet of a plate-shaped magnet into magnetic powder orientation according to the present invention. In the figure, reference numeral 1 is a cavity provided in the molding die, 2 is a main pole, and 3 is a counter electrode. Now, for example, when a synthetic resin magnet in which magnetic powder and synthetic resin are mixed at a predetermined ratio is loaded into the cavity 1 and a magnetic field is applied, magnetic force lines 4 are generated in the direction indicated by the arrow in the figure, and these magnetic force lines 4 The easy axis of magnetization of the magnetic powder particles is oriented along. Here, the radiation of the magnetic force lines is only on the working surface and the side surface, and there is almost no radiation from the surface opposite to the working surface. Further, in the present invention, FIG.
As shown in (a), by reducing the diameter of the counter electrode 3, the orientation direction of the magnetic powder is focused on the central region of the working surface,
The magnetic flux can be effectively reduced, and as a result, the surface magnetic field per unit area on the working surface can be further improved. Further, as shown in FIG. 6B, the magnetic flux can be widened conversely by also deforming the main pole shape.

21 and 22 schematically show a molding die incorporating the magnetic circuit device as described above. 21 shows an example in which the counter electrode 3 has a general shape, and FIG. 22 shows an example in which the counter electrode 3 has an inverted conical shape with a tapered tip.

Next, a magnetic circuit device suitable for aligning the hollow disk-shaped magnet with magnetic particles according to the present invention is shown in FIG.
Shown in (a) and (b). In the figure, reference numeral 5 is a die, 6 is a yoke forming a closed magnetic circuit, and 7 is an exciting coil.

Now, as shown in FIG. 23, when the magnetic field is applied to the synthetic resin magnet material introduced into the disk-shaped cavity 1 by injection molding while it is in the softened state, the magnetic force lines are Disk-shaped cavity 1
In the inside, from the inner and outer surfaces, the light is transmitted so as to be focused on the central ring region of the main pole side track, and therefore the easy axis of magnetization of the magnetic powder particles in the magnet material is the main pole side track along the direction of this magnetic force line. As a result of being oriented so as to be focused in the central ring region, a side-oriented type hollow disk-shaped magnet as shown in FIGS. 5A and 5B is obtained. From the surface of the mold magnetic circuit, as shown in FIG. 23 (b), the diameter of the main magnetic pole is tapered so that the orientation direction of the magnetic powder particles is narrowed down to the central ring region having a narrower working surface. As a result, the peak value of the surface magnetic field can be further improved.

Next, a magnetic circuit device suitable for making the annular magnet the magnetic powder orientation according to the present invention is shown in FIG.
Shown in (b), numeral 8 in the drawing is a permanent magnet for excitation. Now, as shown in FIG. 24, when a magnetic field is applied to the synthetic resin magnet material introduced into the annular cavity 1 by injection molding, for example, while the synthetic resin magnet material is in a softened state, the lines of magnetic force are generated. 1, the light penetrates from both end faces so as to be focused on the central ring zone of the outer circumference of the main pole side, so that the easy axis of magnetization of the magnetic powder particles in the magnet material is the main pole side along the direction of this magnetic force line. As a result of orienting so as to focus on the central annulus region of the outer circumflex, as shown in FIG.
Thus, the laterally oriented annular magnet as shown in (b) can be obtained.

Also in this case, as shown in FIG.
By making the diameter of the main magnetic pole taper, the orientation direction of the magnetic powder particles can be narrowed to a narrower central annular zone region of the working orbiting surface, and as a result, the surface magnetic field peak value can be further improved. 24 (a) and 24 (b) show the case where the outer circumferential surface of the annular magnet is used as the working surface, but the inner circumferential surface of the annular magnet can be used as the working surface.
A preferred example of the magnetic circuit device in this case is shown in FIG.
As shown in.

Next, FIG. 25 (a) shows a magnetic circuit device suitable for making the long rod-shaped magnet the magnetic powder orientation according to the present invention. Now, for example, when a synthetic resin magnet in which magnetic powder and synthetic resin are mixed at a predetermined ratio is loaded into the cavity 1 and a magnetic field is applied while extruding the synthetic resin magnet as shown in FIG. 25 (b). A line of magnetic force is generated in the direction indicated by an arrow in the figure, and the easy axis of magnetization of the magnetic powder particles is oriented along the line of magnetic force. Here, the radiation of the magnetic force lines is only on the working surface and the side surface, and there is almost no radiation from the surface opposite to the working surface. Also in this case, as shown in FIG. 26, by making the tip of the counter electrode 3 small, the orientation direction of the magnetic particles can be focused on the central area of the working surface to narrow down the magnetic flux.
The surface magnetic field peak on the effective surface can be further improved. Such magnets are particularly useful as signal generating magnets.

Next, a magnetic circuit device suitable for forming a magnetic powder orientation that becomes a magnetic pole that is intermittent in the longitudinal direction is shown in FIGS. 27 (a) and 27 (b), taking a long magnet as an example. Well Figure 27
In the place shown in, when a magnetic field is applied to the magnetic material while the synthetic resin magnet material introduced into the cavity 1 by injection molding is in the softened state,
In the cavity 1, the magnetic force lines are transmitted from both side surface regions so as to be focused on each magnetic pole portion on the working surface side, so that the easy axis of magnetization of the magnetic powder particles in the magnet material is focused and oriented along the direction of the magnetic force lines. As a result, a long magnet having a side-focusing orientation as shown in FIG. 12 can be obtained. In the above example, the case where the exciting coil is used as the magnetomotive force generator has been described, but a permanent magnet may be used as long as it is strong.

In each of the magnetic circuit devices described above, the main pole 2, the counter pole 3, and the yoke 6 are carbon steel such as S55C, S50C, and S40C, die steel such as SKD11 and SKD61, and pamendur, and strong iron such as pure iron. The magnetic material, on the other hand, the die 5 is preferably a non-magnetic material such as stainless steel, copper-beryllium alloy, high-manganese steel, bronze, brass and non-magnetic super steel N-7.

[0035]

【Example】

Example 1 Using a molding die incorporating the magnetic circuit device shown in FIGS. 19, 20 and 28 (a), (b) above, the diameters were:
A disk-shaped magnet having a size of 30 mm and a height of 10 mm was molded by the magnetic field orientation injection molding method and the magnetic field orientation compression molding method under the following conditions.

[Table 1] Raw materials ・ Magnetic powder particles Magnetic powder A: Ferrite magnetic powder (magnetoplumbite-based strontium-based ferrite with an average particle size of 1.5 μm Magnetic powder B: samarium-cobalt magnetic powder (Sm ₂ Co ₁₇ system: average particle size 10 μm) ・ Synthetic resin: Polyamide 12 ・ Plasticizer: TTS (isopropyl triisostearoyl titanate)

[0036]

[Table 2] Composition-Composition A (Plamag composition) Magnetic powder: 64 vol% Polyamide 12:35 vol% TTS: 1 vol% -Composition B (Sintering composition) Magnetic powder: 50 wt% Water: 50 wt%

[0037]

[Table 3] Molding conditions ・ Injection molding conditions (field orientation injection molding machine with built-in coil) Pellet formulation used: Formulation A Injection cylinder temperature: 280 ℃ Mold temperature: 100 ℃ Injection pressure: 1500 kg / cm ² Excitation time: 20 seconds Cooling time: 25 seconds Injection cycle: 40 seconds ・ Compression molding conditions Raw material: Compounding B Molding method: Chamber method Excitation method: Vertical magnetic field molding Molding temperature: 25 ℃ Firing temperature: 1250 ℃

The magnetic flux density distribution of the working surface of the disk-shaped magnet thus obtained after magnetization is 70
The measurement was performed by using a Gauss meter incorporating a gallium-arsenic semiconductor having a square of μm. Also, from this, the integrated value of the surface magnetic flux density on the working surface (hereinafter referred to as the linear magnetic flux number)
I asked. The linear magnetic flux number here corresponds to the total area of the magnetic flux distribution as illustrated in Fig. 29.

[Equation 1] It is a value represented by. The survey results are shown in Table 4.

[0039]

[Table 4]

As is clear from the table, the side-oriented anisotropic magnets obtained according to the present invention have a surface on the working surface as compared with the axial-type magnets and the focusing-oriented magnets obtained according to the conventional method. The magnetic field is significantly improved.
Therefore, the side-oriented magnet of the present invention has an advantage that the attraction on the working surface side is significantly improved as compared with the conventional magnet. Further, the disk-shaped magnet obtained according to the present invention was cut along a plane including a rotational symmetry axis, and the orientation of the magnetic powder particles in the cross section was observed by a scanning electron microscope (SEM). As shown in FIG. 1, it was confirmed that the orientation was along the magnetic field lines from the side surface to the working surface.

Example 2 Using a magnetic field orientation molding die incorporating the magnetic circuit device shown in FIGS. 23 (a), (b) and FIG. 30, outer diameter: 60 mm, inner diameter:
A hollow disk-shaped magnet with dimensions of 48 mm and thickness: 2 mm was manufactured under the following conditions. The raw materials and formulation were the same as in Example 1 except that Aminosilane A-1100 was used as the plasticizer for plastic mag.

[0042]

[Table 5] Molding method A: Plamag injection molding conditions Pellet mix used: Mixture A Molding machine: Magnetic field orientation injection molding machine with built-in coil Injection cylinder temperature: 300 ° C Mold temperature: 100 ° C Injection pressure: 1800 kg / cm ² Excitation Time: 15 seconds Cooling time: 20 seconds Injection cycle: 40 seconds ・ Molding method B: Sintered magnet making conditions Slurry used: Compound B Molding machine: Coil-mounted magnetic field orientation compression molding machine Molding method: Injection method Excitation direction: Vertical magnetic field Molding temperature: 20 ° C Firing temperature: 1250 ° C

After the demagnetization of the hollow disk-shaped magnet thus obtained, the peak value of the surface magnetic flux density on the effective working surface when re-magnetized to 48 poles was measured using the above-mentioned Gauss meter. The results are shown in comparison with Table 6.

[0044]

[Table 6]

As is apparent from the table, magnetic powder particles in the hollow disk-shaped magnet are densely focused on the central ring region of the working surface side track by using the magnetic circuit device of the magnetic field orientation molding die according to the present invention. As a result, the peak value of the surface magnetic flux density on the effective surface can be significantly improved. Further, when the hollow disk-shaped magnet obtained according to the present invention was cut along a plane including the axis of rotational symmetry and the orientation of the magnetic powder particles in the cross section was observed by SEM, most of the magnetic powder particles were as shown in FIG. ), (B), it was confirmed that they are oriented along the magnetic lines of force from the side surface to the working surface.

Example 3 Using a magnetic field orientation molding die incorporating the magnetic circuit device shown in FIGS. 24 (a), (b) and FIG. 31, an outer diameter: 60 mm, an inner diameter:
An annular magnet with dimensions of 56 mm and thickness: 6 mm was manufactured.
The raw materials, the composition and the molding method are the same as in the case of Example 2.

After demagnetizing the thus obtained annular magnet, the peak value of the surface magnetic flux density on the effective working surface when re-magnetized to 48 poles was measured using the above-mentioned Gauss meter. It shows in comparison with 7.

[0048]

[Table 7]

As is clear from the table, by using the magnetic circuit device of the magnetic field orientation molding die according to the present invention, the magnetic powder particles in the annular magnet are densely focused in the central annular zone region of the outer peripheral surface of action. The peak value of the surface magnetic flux density on the effective surface can be significantly improved. Further, when the annular magnet obtained according to the present invention was cut along a plane including a rotational symmetry axis and the orientation of the magnetic powder particles in the cross section was observed by SEM, most of the magnetic powder particles were as shown in FIG.
As shown in (a) and (b), it was confirmed that the orientation was along the magnetic lines of force extending from the side surface to the working surface.

Example 4 A magnetic field orientation molding die incorporating the magnetic circuit device shown in FIGS. 25 and 26 and a magnetic field orientation molding die incorporating a conventional magnetic circuit device for focusing orientation (not shown) are used. A long magnet having dimensions of width: 12 mm, thickness: 4 mm and length: 125 mm and a working zone width of 6 mm was molded under the following conditions. In the experiment using the magnetic powder B shown below, a giant magnetic field having a pulse shape was applied in advance, and the magnetic moments of the magnetic powder were aligned to perform magnetic field orientation molding.

[0051]

[Table 8] Raw materials / Magnetic powder particles Magnetic powder A: Ferrite magnetic powder (magnetoplumbite-based strontium-based ferrite with an average particle size of 1.5 μm) Magnetic powder B: Samarium-cobalt magnetic powder (2-17 system; average particle size 15 μm) -Synthetic resin: Chlorinated polyethylene-Plasticizer: DOP (Dioctyl phthalate) -Others: Polyethylene wax TTS (Isopropyltriisostearoyl titanate)

[0052]

Table 9 formulations, formulation A (plastic magnet formulation) magnetic powder A: 61.5 vol% chlorinated polyethylene: 16 vol% DOP: 21.5 vol % of polyethylene wax: 0.5 vol% TTS: 0.5 vol % · formulation B (sintered blend) Magnetic powder: 50 wt% Water: 50 wt%

[0053]

[Table 10] Molding conditions / extrusion molding conditions Pellet composition used: Compound A Extrusion cylinder temperature: 160 ° C Temperature near discharge port: 160 ° C Discharge speed: 2 m / min Extruder: Full flight type Cylinder length 70 mm (Cylinder length ) / (Inner diameter) = 22 Compression ratio 3 Excitation coil magnetomotive force: 10000 A / m Land magnetic field application width: 70 mm ・ Compression molding conditions Raw material: Compound B Molding method: Injection method Excitation direction: Compression direction Excitation coil magnetomotive force : 10,000 A / m Molding temperature: 20 ° C Firing temperature: 1250 ° C

Table 11 shows the results of examining the surface magnetic field of the long magnet thus obtained after magnetization, and particularly the starting torque (motor characteristics) of the synthetic resin magnet. The motor characteristics are evaluated by the rotor 10 arranged facing the stator 9 in the flat motor shown in FIG.
As a result, after the flexible long magnet obtained as described above was magnetized, it was wound inside the rotor yoke 11 and disposed, and the starting torque was measured. In the figure, reference numeral 12
Is the upper case, 13 is the shaft, 14 is the stator yoke, and 15
Is the lower case.

[0055]

[Table 11]

The evaluation conditions are as follows.

[Table 12] Magnet outer diameter: 40 mm Inner diameter: 34 mm Thickness: 9 mm Focusing ratio: 45% ・ Stator width: 5 mm ・ Drive method 3 phase voltage: 12 V Current: 200 mA / phase 8 poles ・ Hall element 70 μm square gallium − Arsenic semiconductor

As is clear from Table 11, in all of the long magnets obtained according to the present invention, the surface magnetic field on the working surface was remarkably improved as compared with those obtained according to the conventional method. It was confirmed that the torque characteristics and the adsorption force on the iron plate can also be improved. Further, when the long magnet obtained according to the present invention was cut perpendicularly to the longitudinal direction and the orientation of the magnetic powder particles in the cross section was observed by SEM, most of the magnetic powder particles were observed from the side surface as shown in FIG. It was confirmed that they were oriented along the magnetic field lines toward the working surface.

Example 5 Using a mold having a magnetic circuit as shown in FIG. 27,
A long magnet having the shape and dimensions shown in FIG. 33 was produced under the following conditions. For comparison, a conventional mold (not shown)
A magnet of the same size was also manufactured using.

[0059]

[Table 13] Magnetic circuit device • Magnetomotive force generation part If the magnetic powder is ferrite type, rare earth type (Sm-Co) permanent magnet is used. If the magnetic powder is rare earth, an electromagnet method is used. The pole shape is 4mm for the main pole
× 8 mm, arranged at a predetermined pitch, while the counter electrode is 8 mm
It was a continuous pole of width.・ Uses ferromagnetic material SKD11.・ Other mold members SUS 304.

[0060]

[Table 14] Raw material-Magnetic powder particles Magnetic powder A: Ferrite magnetic powder (magnetoplumbite-based strontium-based ferrite with an average particle size of 1.5 μm Magnetic powder B: samarium-cobalt magnetic powder (Sm ₂ Co ₁₇ system: average particle size 20 μm) -Synthetic resin: Polyamide 12 ・ Plasticizer: TTS (isopropyl triisostearoyl titanate)

[0061]

[Table 15] Composition-Composition A (Plamag composition) Magnetic powder: 66 vol% Polyamide 12:33 vol% TTS: 1 vol% -Composition B (Sintering composition) Magnetic powder: 40 wt% Water: 60 wt%

[0062]

[Table 16] Molding conditions ・ A: Injection molding conditions Injection cylinder temperature: 300 ℃ Mold temperature: 100 ℃ Injection pressure: 1800 kg / cm ² Cooling time: 15 seconds Injection cycle: 30 seconds ・ B: Compression molding conditions Water removal Method: Injection method Molding temperature: 20 ℃ Firing temperature: 1250 ℃

Table 17 shows the results of examining the surface magnetic field (peak value) after demagnetizing the long magnet thus obtained and again magnetizing it as shown in FIG. The magnetizing conditions were 1200 V and 1500 μF, and the magnetizing yokes had a pitch matched with the focusing pitch.

[0064]

[Table 17]

As is clear from Table 17, in all of the long magnets in the magnetic powder orientation according to the present invention, the peak value of the surface magnetic field is remarkably improved as compared with the magnet obtained by the conventional method.

[0066]

As described above, according to the present invention, the surface magnetic field and the magnetic field line arrival length on the working surface of the magnet can be remarkably improved, and even if it is a ferrite synthetic resin magnet, the conventional ferrite sintered magnet is used. It is possible to obtain a surface magnetic field exceeding that.

[Brief description of drawings]

FIG. 1A is a magnetic force diagram of a conventional axial disk magnet. (B) is the figure which showed the surface magnetic field pattern in the working surface of this magnet.

FIG. 2A is a diagram showing a magnetic field line distribution of a conventional focusing orientation type disk-shaped magnet. (B) is the figure which showed the surface magnetic field pattern in the working surface of this magnet.

FIG. 3 (a) is a diagram showing a magnetic field line distribution of a side surface-oriented disc-shaped magnet according to the present invention. (B) is the figure which showed the surface magnetic field pattern in the working surface of this magnet.

FIG. 4 is a diagram showing an orientation state of an easy axis of magnetization of magnetic powder particles in a conventional hollow disk-shaped magnet.

FIG. 5 is a diagram showing the orientation state of the easy axis of magnetization of the magnetic powder particles in the hollow disk-shaped magnet according to the present invention.

FIG. 6 is a diagram showing the orientation state of the easy axis of magnetization of magnetic powder particles in a conventional annular magnet.

FIG. 7 is a diagram showing the orientation state of the easy axis of magnetization of the magnetic powder particles in the annular magnet according to the present invention.

FIG. 8A is a diagram showing the orientation state of the easy axis of magnetization of magnetic powder particles in a conventional axial long magnet.
(B) is a figure showing distribution of magnetic force lines of the magnet.
(C) is a diagram showing a surface magnetic field pattern on the working surface of the magnet.

FIG. 9A is a diagram showing the orientation state of the easy axis of magnetization of the magnetic powder particles in the lateral orientation type long magnet according to the present invention. (B) is a figure showing distribution of magnetic force lines of the magnet.
(C) is a diagram showing a surface magnetic field pattern on the working surface of the magnet.

FIG. 10 is a schematic view of a side-face oriented long magnet having opposing short sides as working surfaces.

FIG. 11 is a schematic diagram showing a preferred cross-sectional shape of a long magnet.

FIG. 12 is a diagram showing the orientation of the easy axis of magnetization of the magnetic powder particles of the disk-shaped magnet, the hollow disk-shaped magnet, and the ring-shaped magnet whose opposite surfaces are acting surfaces.

FIG. 13A is a perspective view of a side-oriented long magnet having intermittent magnetic pole portions. (B) is the figure which showed the orientation state of the easy axis of magnetization of a magnetic particle in the longitudinal cross section of this magnet. FIG. 6C is a diagram showing the orientation state of the easy axis of magnetization of the magnetic powder particles in the widthwise cross section of the magnet.

FIG. 14A is a diagram showing a surface magnetic field pattern when a long magnet having a magnetic powder orientation according to the present invention is magnetized. (B) is a diagram showing a surface magnetic field pattern when a conventional magnet having a thickness direction orientation is magnetized.

FIG. 15 is a view showing a side surface oriented type annular magnet having intermittent magnetic pole portions.

FIG. 16 is a view showing the orientation state of the easy axis of magnetization of magnetic powder particles of a hollow disk-shaped magnet and an annular magnet in which opposite surfaces are used as working surfaces and magnetic poles are provided intermittently on the working surfaces.

FIG. 17 is a view showing another preferable shape of the sideways oriented magnet according to the present invention.

FIG. 18 is a diagram showing the orientation state of the easy axis of magnetization of the magnetic powder particles of the side surface orientation type flat magnet according to the present invention.

FIG. 19 is a schematic diagram of a magnetic circuit device suitable for use in manufacturing the side-oriented disc-shaped magnet of the present invention.

FIG. 20 is a schematic view of another magnetic circuit device suitable for use in manufacturing the side-oriented disc-shaped magnet of the present invention.

FIG. 21 is a schematic view of a magnetic field orientation injection molding machine incorporating a magnetic circuit device for manufacturing a side-oriented disc-shaped magnet.

FIG. 22 is a schematic view of another magnetic field orientation injection molding machine incorporating a magnetic circuit device for manufacturing a side-oriented disc-shaped magnet.

FIG. 23 is a schematic view of a magnetic circuit device suitable for use in the manufacture of the side-oriented type hollow disk-shaped magnet of the present invention.

FIG. 24 is a schematic view of a magnetic circuit device that is suitable for use in manufacturing the laterally oriented annular magnet of the present invention.

FIG. 25 (a) is a schematic view of a magnetic circuit device suitable for use in the manufacture of the laterally oriented long magnet of the present invention.
(B) is a schematic diagram showing an extrusion molding procedure in the apparatus.

FIG. 26 is a schematic view of another magnetic circuit device suitable for use in the manufacture of the laterally oriented long magnet of the present invention.

FIG. 27 is a schematic diagram of a magnetic circuit device suitable for use in manufacturing a side-oriented long magnet having intermittent magnetic pole portions.

FIG. 28 (a) is a schematic view of a conventional magnetic circuit device of an axial disk magnet. (B) is a schematic diagram of a conventional magnetic circuit device of a focusing orientation type disc magnet.

FIG. 29 is an explanatory diagram of a calculation procedure of the number of linear magnetic fluxes.

FIG. 30 is a schematic view of a conventional magnetic circuit device for manufacturing an axial hollow disk-shaped magnet.

FIG. 31 is a schematic diagram of a conventional magnetic circuit device for manufacturing an axial annular magnet.

FIG. 32 is a schematic diagram of a motor.

FIG. 33 is a diagram showing the shape and dimensions of the long magnet manufactured in Example 5;

FIG. 34 is a diagram showing a way of magnetizing the long magnet.

[Explanation of symbols]

 1 Cavity 2 Main Pole 3 Counter Pole 4 Magnetic Field Line 5 Die 6 Yoke 7 Excitation Coil 8 Excitation Permanent Magnet 9 Stator 10 Rotor 11 Rotor Yoke 12 Upper Case 13 Shaft 14 Stator Yoke 15 Lower Case

 ─────────────────────────────────────────────────── ─── Continuation of the front page (31) Priority claim number Japanese Patent Application No. 3-306314 (32) Priority date Hei 3 (1991) November 21 (33) Priority claim country Japan (JP) (31) Priority Claim No. Japanese Patent Application No. 4-38014 (32) Priority Day No. 4 (1992) February 25 (33) Country of priority claim Japan (JP) (31) No. of priority claim Japanese Patent Application No. 4-150724 (32) Priority Hihei 4 (1992) June 10 (33) Priority claiming country Japan (JP) (72) Inventor Akira Yasuda 2-3-2 Uchisaiwaicho, Chiyoda-ku, Tokyo Kawasaki Steel Co., Ltd. Tokyo headquarters (72) Inventor Koichi, 1 Kawasaki-cho, Chiba, Chiba Prefecture, Technical Research Headquarters, Kawasaki Steel Co., Ltd. (72) Takahiro Kikuchi, 1 Kawasaki-machi, Chiba, Chiba Prefecture

Claims (7)

[Claims] 1. A permanent magnet having a working surface and a side surface adjacent to the working surface, wherein the easy axis of magnetization of magnetic powder particles constituting the magnet is oriented substantially along a magnetic field line extending from the side surface to the working surface. A laterally oriented anisotropic magnet characterized in that 2. The side-oriented anisotropic magnet according to claim 1, wherein the magnet has a flat plate shape. 3. The magnet shape is a hollow disk shape.
The laterally oriented anisotropic magnet described. 4. The side-oriented anisotropic magnet according to claim 1, wherein the magnet has an annular shape. 5. The side-oriented anisotropic magnet according to claim 1, wherein the magnet has a long rod shape. 6. The side-oriented anisotropic magnet according to claim 2, 3, 4 or 5, having working surfaces on both surfaces facing each other. 7. The side-oriented anisotropic magnet according to claim 2, 3, 4, 5 or 6, wherein the working surface has a plurality of intermittent working areas.