JPH05101956A - Manufacture of anisotropic magnet of cylindrical shape - Google Patents

Abstract

PURPOSE:To satisfactorily anisotropically orient material for magnet without using an electromagnet as magnetic field generating means for anisotropically orienting and to easily and inexpensively manufacture anisotropic magnets of cylindrical shape each having high performance in mass production by extrusion molding. CONSTITUTION:An apparatus for manufacturing anisotropic magnets of cylindrical shape, having magnetic field generating means 8 around a mold 3 provided at a protruding port 1 of an extruder for extruding kneaded mixture of magnetic powder and binder comprises a plurality of pole magnets 8a made of permanent magnets around a cylindrical molding hole (h) as the means 8 and so disposed that both the poles are radial and the polarities of the inner poles of the adjacent poles are different. Simultaneously, auxiliary magnets 8b of the same material as those of the poles are so disposed between the adjacent poles that both the poles are disposed circumferentially and the polarities of the poles are the same as those of the inner poles of the adjacent pole magnets, and a ringlike yoke 8c made of a ferromagnetic material is disposed on the outer periphery of the magnets.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing a cylindrical anisotropic magnet, and more particularly to an apparatus for producing a magnet by extruding magnetic powder as a main raw material.

[0002]

2. Description of the Related Art Conventionally, when manufacturing a permanent magnet using a magnetic powder such as a ferrite magnet or a rare earth magnet as a raw material,
Mostly, it is based on the sintering-finishing process, and the molding process is mostly based on the compression molding method. For example, when an anisotropic ferrite magnet is manufactured by compression molding, ferrite magnetic powder m crushed to a size of substantially unit crystal grains as shown in FIG. The magnetic powder is housed in a mold, and the spontaneous magnetization direction (C axis) of the magnetic powder is aligned in a predetermined direction. Then, the molded product is sintered and finished. In this case, a stronger magnet is obtained as the degree of orientation of the crystal particles is higher, and when manufactured by compression molding as described above, filling of powder raw material, magnetic field oscillation, compression,
Operations such as demagnetization, pressure release, and work discharge with the orientation fixed 1
A strong anisotropic magnet can be manufactured by performing the steps carefully in every round molding. On the other hand, there are problems that the device configuration becomes complicated, and that molding takes time and manufacturing cost increases.

Further, the anisotropic method for manufacturing the cylindrical anisotropic magnet Mg as shown in FIG. 10 is divided into two methods, a radial anisotropic method and a polar anisotropic method. The radial anisotropy is a process in which the spontaneous magnetization axis (C axis) of the magnetic powder crystal particles m is evenly arranged in the radial direction with respect to the cylindrical axis as shown in FIG. As shown in FIG. 9 (a), the generation of a predetermined magnetic pole in a molding die
Only the particles in the mold cavity near the pole are partially anisotropically compressed. The radial anisotropic magnet is magnetized by a magnetizing yoke 51 having a predetermined number of poles, as shown in FIG. 8B, after a molding step, a sintering step, and a finishing step. Reference numeral 52 represents a winding. On the other hand, the polar anisotropic magnet is formed into a pole of the magnetizing yoke 51 having a predetermined number of poles as shown in FIG. It is necessary to match the orientation poles of the particles formed by the method and to magnetize them. In the compression molding method, both radial anisotropic molding and extreme anisotropic molding can be applied, but the order of completing powder filling-magnetic field generation-compression-demagnetizing field application-pressure release-workpiece extraction for each molding. For that purpose, the magnetic field generation method is performed by an electric method, and the magnetic field is turned on and off in synchronization with the molding procedure. For that purpose, a complicated combination of windings, yokes, and powder-filled cavities is required, and the setting of the sequence must be complicated. Radial anisotropy and polar anisotropy are also suitable for the production of large cylindrical multipole magnets due to the structure of the respective magnetic field generating means, but there is a design limitation for the production of small magnets. In particular, the recent multi-pole cylindrical magnets for small stepping motors have 8 poles, 10 poles on the outer circumference of diameters of 10 mm, 8 mm, 6 mm, etc.
There are requirements for 12 poles, 16 poles, etc., and there are some that cannot be handled by a compression molding machine.

On the other hand, it is also known to manufacture a permanent magnet by extrusion molding. The extrusion molding method as a so-called resin magnet manufacturing method and the molding for manufacturing a magnet by molding and sintering are carried out by extrusion molding. There are things. The former is easy to manufacture because a product can be obtained without sintering after extrusion molding, but an anisotropic magnet having a large magnetic force cannot be obtained. Examples of the latter which are extruded and then sintered include those disclosed in JP-A-56-125813.
Japanese Laid-Open Patent Publication No. 56-125814 is proposed. This is an application of extrusion molding to the manufacture of cylindrical radial anisotropic magnets. A molding die with a cylindrical molding hole is placed at the discharge port of the extruder, and one or two sets of electromagnetic coils are placed in this. A radial magnetic field is formed in the cylindrical molding hole by the (electromagnet), and the kneaded material of the magnetic powder and the binder is continuously extruded and molded, and at the same time, the orientation treatment is performed.

[0005]

However, the one using the electromagnet as described above requires a winding and has a complicated shape.
In addition, there is a limit to making the magnet oriented in the small and small directions extremely polar. In addition, uncertain conditions such as heat generation during long-time use may occur, which may interfere with extrusion molding and the alignment treatment and alignment fixing performed at the same time. Further, there is a problem that electric power is required to generate a magnetic field, which increases manufacturing costs.

Further, the above-mentioned conventional device does not take any means for maintaining the orientation of the magnetic particles during the molding, and the ratio of the magnetic powder to the binder and the water does not change even after passing through the molding die. Since the movement of the powder is in a free state, for example, as shown in (a) and (b) of FIG.
1 or iron yoke 62, when passing through a mold having magnetic field generating means, even if the particles are oriented in the magnetic field, they are attracted by the magnetic field of the mold at the time of exiting the magnetic field and oriented backward. There was a risk of it. Moreover, since the molded product is magnetized even after molding, for example, a product oriented in a magnetic field as shown in FIG. 12 (a) or FIG. 13 (a) is cut, dried and baked. Until the connection, there was a problem that due to the action of the internal demagnetizing field, the orientation was broken as shown in FIG. 12 (b) or FIG. 13 (b) and a strong magnet could not be obtained. Note that FIG. 12 shows the case where adjacent poles are nearby, and FIG. 13 shows the case where the same pole is continuous.

The present invention has been proposed in view of the above problems, and makes it possible to favorably achieve anisotropic orientation without using an electromagnet as a magnetic field generating means for anisotropic orientation, and to provide orientation It is an object of the present invention to provide a manufacturing apparatus capable of maintaining and mass-producing high-performance cylindrical anisotropic magnets easily and inexpensively.

[0008]

In order to achieve the above object, the apparatus for producing a cylindrical anisotropic magnet according to the present invention has the following constitution. That is, a discharge die of an extruder for extruding a kneaded product of magnetic powder and a binder is provided with a forming die having a cylindrical forming hole, and a magnetic field is generated in the cylindrical forming hole by a magnetic field generating means arranged around the forming die. In a device for producing a cylindrical anisotropic magnet by extruding the kneaded material in a generated state, a polar magnet consisting of a plurality of permanent magnets, both poles of which are around the cylindrical molding hole as the magnetic field generating means, The poles are arranged so that they are in the radial direction and the inner poles of adjacent pole magnets are different from each other, and an auxiliary magnet made of a permanent magnet of the same material as that of the two poles is provided between the adjacent pole magnets. Are arranged in the circumferential direction and their poles are the same as the inner poles of the adjacent pole magnets, and a ring-shaped yoke made of a ferromagnetic material is arranged on the outer circumference of those magnets. It is characterized by having done. Further, the above-mentioned molding die is provided with a cylindrical sizing pipe made of a non-magnetic material and a prolong in a continuous manner, and a core is arranged inside thereof, and the outer periphery of the sizing pipe and the prolong is arranged. The magnetic field generating means is arranged, and the cooling means is arranged in close contact with the outer peripheral surface of the prolong and the side surface of the magnetic field generating means.

[0009]

By using the permanent magnet as the magnetic field generating means and arranging the pole magnet and the auxiliary magnet as described above, a strong pole magnetic field is formed in the cylindrical molding hole, and the kneaded material is formed in the molding hole. When it passes through and is molded into a cylindrical shape, it is possible to favorably and reliably achieve anisotropic orientation. Further, the molding die, a cylindrical sizing pipe made of a non-magnetic material and a prolong are continuously provided, and the magnetic field generating means is arranged on the outer periphery of the sizing pipe and the prolong, and the outer peripheral surface of the prolong is formed. By arranging the cooling means in close contact with the side surface of the magnetic field generating means, the orientation of the work is completed while the magnetic field is passing, and the orientation can be fixed in that state.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on the embodiments shown in the drawings. FIG. 1 is a vertical cross-sectional side view showing an embodiment of an apparatus for manufacturing a cylindrical anisotropic magnet according to the present invention, and FIG. 2 is an enlarged cross-sectional front view of a main part thereof. In the figure, 1 is a discharge port of an extruder, and the kneading / extruding mechanism and the like of the extruder are omitted in the figure, but if the magnetic powder and the binder can be kneaded, degassed, and extruded, it is conventionally known. Various configurations are applicable. A molding die 3 is connected to the ejection port 1 via an introduction member 2 made of a non-magnetic material, and the ejection port 1 and the introduction member 2 are connected to the molding die 3.
Introducing passage 1 for guiding the above kneaded material into molding die 3 inside
a * 2a is formed. 1b and 2b are the discharge ports 1
And the introduction member 2 are connected to each other by a flange 4 and the introduction passage 1 described above.
It is a heating coil for keeping the temperature of the kneaded material flowing in a.2a.

The molding die 3 has a cylindrical sizing pipe 5 made of a non-magnetic and wear-resistant material, and the same material as that of the sizing pipe 5 in the extension of the introduction passage 2a. A slightly larger cylindrical prolong 6 is continuously provided, and a core 7 made of a ferromagnetic material made of iron or the like is arranged in the inner space of the prolong 6 and between the sizing pipe 5 and the core 7. A cylindrical forming hole h is formed in the. Also sizing pipe 5 and prolong 6
A magnetic field generating means 8 is provided on the outer periphery of the so as to cover a part of the sizing pipe 5 and the prolong 6,
Cooling means 9 is provided in close contact with the side surface of the magnetic field generating means 8 and the outer peripheral surface of the prolong 6. The cooling means 9
In the case of the figure, the water passage hole 9b is formed inside the cooling member 9a having good thermal conductivity, and the cooling water is passed through the water passage hole 9b to cool.

As the magnetic field generating means 8 in the present invention, a permanent magnet such as a rare earth iron magnet or a rare earth cobalt magnet having a high residual density and a high coercive force is used. No electromagnet is used: a) Extrusion molding is continuous, and therefore, a sequence of generating and erasing a magnetic field is not required for each molding. b) The electromagnet has a complicated shape because it requires a winding, and there is a limit to making the magnet oriented in the small and small directions extremely polar. c) In this extrusion method, the length of the magnetic field band is required because the work is oriented and fixed and hardened during passage of the effective magnetic field. Therefore, the pole length of the electromagnet is also required, and the generation of magnetic force by the electromagnet is limited. In addition, uncertain conditions such as heat generation during long-term use occur. Therefore, in the effective magnetic field,
The permanent magnet method is much easier for temperature control of high temperature orientation and cooling and hardening. d) Molding cost The power cost for generating the medium magnetic field occupies a large weight, but the permanent magnet system does not require power. Etc.

Next, in determining the arrangement configuration of the permanent magnets used in the magnetic field generating means 8, as a result of various basic experiments, as shown in FIG. 4, the permanent magnets are formed on the yoke 10 made of iron or the like. It is most preferable that the main magnet 11 and the auxiliary magnet 12 are formed as shown in the figure, and that when the pole width of the main magnet 11 is Lm and the pole interval is Lf, Lm / Lf = 2. I found out. Reference numeral 13 denotes a yoke made of iron or the like arranged above the magnets 11 and 12, and corresponds to the core 7. The distance Yd between the yoke 13 and the main magnet 11 is 3.5.
mm, the pole width Lm of the main magnet 11 is 1.5 mm, the pole spacing Lf
Is 2 mm, and a rare earth iron magnet (Br12KG bHc11.5 KOe) is used as the main magnet 11 and the auxiliary magnet 12, and the magnetic force generated at the pole of the main magnet 11 on the side opposite to the yoke 10 is set to a predetermined value from the main magnet 11. When the probe was placed at a position separated by a distance, the measurement was performed, and the result as shown in FIG. 5 was obtained. The horizontal axis of FIG. 5 is the distance Lg from the main magnet 11, and is 70 when the distance from the main magnet is around 1 mm.
Approximately 6000G was shown in the vicinity of 00G and 2 mm. Although the main magnet 11 and the auxiliary magnet 12 are linearly arranged in FIG. 4, similar results can be obtained when they are cylindrically arranged.

When the above-mentioned structure is applied to a cylindrical outer peripheral multi-pole anisotropic magnet, the thickness of the magnet in the radial direction is generally required to be about 1.5 to 3 mm, and the measuring distance is 1 mm.
The thickness of up to 1.5 mm is a position corresponding to the outer peripheral surface of the work in consideration of the thickness of the sizing pipe fitted inside the magnetic pole during extrusion molding. Therefore, the measurement distance Lg = 1 to 2
The magnetic field of 7,000 G to 6000 G in mm is a sufficient magnetic field necessary for the orientation of the magnetic powder particles in the practical stage.

From the above results, in the present invention, the magnetic field generating means 8 for manufacturing the cylindrical multipole anisotropic magnet is as shown in FIG. That is, the pole magnets 8a, which are in contact with the outer circumference of the sizing pipe 5 and are made of permanent magnets such as rare earth iron magnets corresponding to the main magnets 11, are arranged at equal intervals so that the sizing pipe 5 side has different poles alternately. The auxiliary magnet 1 is provided between the adjacent pole magnets 8a and 8a.
An auxiliary magnet 8b made of a permanent magnet such as a rare earth iron magnet corresponding to 2 is placed in contact with the pole magnet 8a. The auxiliary magnets 8b are arranged such that the poles are in the circumferential direction, and
The pole of the auxiliary magnet is arranged so as to be the same as the pole inside the pole magnet adjacent to it. That is, if the inside of the pole magnet 8a is the N pole, the N poles of the auxiliary magnets 8b on both sides contacting it are
It is made to face the pole magnet 8a side. The same applies to the S pole. A cylindrical yoke 8c is arranged in contact with the outer circumference of each of the magnets 8a and 8b. With this arrangement, the S. This means that the N magnetic poles are arranged alternately, and the yoke 8c on the outer periphery closes the magnetic path to eliminate leakage, and the leakage of the magnetic field is concentrated on the tip of the pole magnet 8a on the inner diameter side.

When a cylindrical anisotropic magnet is manufactured using the manufacturing apparatus configured as described above, a binder is mixed with magnetic powder such as a ferrite magnet that has been sufficiently ground to about a unit crystal grain size. .. As the binder, for example, one or both of hydroxyethyl cellulose and polyethylene oxide, water, and polyethylene glycol are used. The compounding ratio in that case is, for example, 0.1 to 6.0 parts by weight of one or both of hydroxyethyl cellulose and polyethylene oxide in 100 parts by weight of magnetic powder, 5 to 20 parts by weight of water, Polyethylene glycol 0.1 to
It may be about 20 parts by weight.

The mixture of the magnetic powder and the binder is put into an extruder, and the mixture is thoroughly kneaded and deaerated by a kneading / extruding mechanism (not shown in the figure) in the extruder to 50 ° C. to 90 ° C.
Within a range of, for example, 70 ° C., and the kneaded product is continuously and continuously extruded from the discharge port 1 of the extruder. Then, the kneaded material is introduced into the sizing pipe 5 of the molding die 3 via the introduction member 2. At this time, the kneaded material is kept in a fluidized state by being maintained at, for example, 70 ° C. by the heating coil 4 for heat retention in order to improve the orientation mobility of the magnetic particles.

The kneaded material introduced into the above-mentioned sizing pipe 5 is successively formed into a cylindrical shape by its forming hole h, and at the same time, the magnetic particles in the kneaded material have a predetermined amount due to the action of the magnetic field by the magnetic field generating means 8. Oriented in the direction. In particular, in the embodiment of the present invention, the magnetic field generating means 8 includes a plurality of pole magnets 8a made of a permanent magnet such as a rare earth iron magnet and an auxiliary magnet 8.
Since b and b are used and arranged as described above, a strong magnetic field can be obtained and good polar anisotropic multipolar alignment can be performed.

Next, the formed body (workpiece) W which is formed into a cylindrical cross section by the sizing pipe 5 is successively guided into the prolong 6 while being subjected to the magnetic field by the magnetic field generating means 8, and the prolongation thereof is carried out. In the process of passing through the long 6, it is gradually cooled to about room temperature, for example, about 25 ° C., and is sequentially discharged from the pro long 6. Therefore,
The magnetic particles are cooled by the action of the magnetic field while maintaining the above-mentioned oriented state, and the molded body rapidly increases in hardness and is fixed and discharged while keeping the above-mentioned oriented state. is there.

FIG. 3 shows the relationship between the temperature change of the kneaded product and the molded product at this time and the orientation, the orientation fixing, and the shape fixing of the particles. The properties of the kneaded product are shown on the right side of the figure.
After the viscosity is lowered in the temperature range of about 90 ° C. to 90 ° C. to improve the fluidity of the kneaded product and the orientation is completed, the temperature is about 60 ° C. to 4 °
At 0 ° C., the viscosity is increased, the hardness is increased, the progress is made, and the cooling and hardening is performed so as to be 40 ° C. or less before passing through the mold magnetic field. After all, the molded body is cooled to about room temperature and passes through the magnetic field in a solidified or semi-solidified state. Since the molded product is almost solidified at this stage, the particle orientation is not disturbed and leaves the magnetic field, and the molded product is discharged through the prolong 6.

Next, the molded product is dehydrated by performing a vacuum dehydration operation or the like at room temperature, that is, the molded product is completely hardened (completely solidified), and an alternating magnetic field is applied to force demagnetization and a predetermined length. The cutting is performed to complete the process for the sintering process. Then, a product is obtained through a sintering process.

As described above, in the embodiment of the present invention,
Easy to create a cylindrical anisotropic multi-pole magnet with good anisotropic orientation
It is possible to mass-produce at low cost. Further, in the past, generally, in extrusion molding, since a large amount of binder and water are contained, the density of the product is usually inferior to that in compression molding, but in the present invention, the density at the end of sintering is 4.75 to.
Which is 4.83, and the density in the case of the compression molding method is 4.9 to
It was able to be about 5.1. Therefore, by increasing the degree of orientation, it is possible to obtain an anisotropic magnet having performance equivalent to or better than that obtained by the compression molding method.

[Experimental Example] 40 kg of strontium ferrite powder, 3 kg of polyethylene glycol powder,
0.2 kg of hydroxyethyl cellulose was prepared in advance. Strontium ferrite powder has an average particle size of 1.0μ
First, m and polyethylene glycol having an average molecular weight of 20,000 and being powdery, and hydroxyethyl cellulose being powdery are first thoroughly mixed by a mixer. Then water 5.
5 kg was added thereto, and the mixture was put into a kneading machine to be kneaded and deaerated. Next, vacuum deaeration was performed, and the mixture was put into an extruder having a heating cylinder to perform extrusion molding. The inner diameter (diameter) of the sizing pipe at the discharge part of the extruder is 11.1 m.
m, the outer diameter of the core was 5.31 mm, and the number of magnetic poles was 10. As the magnetic field generating means, a combination structure of the rare earth magnets as in the above embodiment is used. The magnetic flux density on the inner peripheral surface of the sizing pipe was 6380 gauss. The length of the magnetic field generating means was 120 mm. The temperature of the kneaded product in the extruder was 70 ° C., and water was used at 20 ° C. for cooling to obtain a semi-solid long cylindrical molded product. The dimensions of the molded product were an outer diameter of 11.1 mm and an inner diameter of 5.31 mm.
This was cut into a length of about 300 mm and placed in a vacuum dryer. The vacuum dryer used was a 5.5 kW water-sealed vacuum pump, and the degree of vacuum was 500 mmHg, and the drying was performed for about 2 hours. Due to the above, the water content in the molded product is less than 4%,
The molded product became a hard solid. Next, this was demagnetized by a pulse demagnetizer from a peak output of 1500 A by alternating attenuation, then cut to 22 mm and sintered at 1220 ° C. for 10 hours. A cylindrical magnet having an outer diameter of 8 mm, an inner diameter of 4 mm and a length of 15 mm was obtained from the sintered product by a cylindrical grinder. Further, the inner diameter was 8.05 mm, a 10-pole yoke was used, the output was 200 μF, and a multi-pole magnet having an outer periphery of 10 poles was obtained with an output of 1500 V.

COMPARATIVE EXAMPLE 1 Next, as a comparative example of the above experimental example, the conditions of the molding ferrite powder, binder, water, etc. were completely the same as those of the experimental example, and the molding die used was the same as that of the experimental example. did. The kneading conditions were the same, and molding was performed, and cooling was not performed during molding. The moldings were obtained in a very soft state. Let it harden by natural cooling and
It was cut to a length of 0 mm and put into vacuum drying. After that, through the same steps as in the above-mentioned experimental example, a 10-pole multi-pole magnet having an outer diameter of 8 mm, an inner diameter of 4 mm, and a length of 15 mm was obtained.

Comparative Example 2 As yet another comparative example, an isotropic one prepared by a conventional compression molding method was prepared and subjected to the same magnetization. The magnet characteristics of the magnets obtained in the above experimental example and comparative examples 1 and 2 are shown in (a) to (c) of FIG. 16 and Table 1 below, respectively. The ratios in the above table are the ratios when the average pole magnetic flux of Comparative Example 2 is 100, and the anisotropic magnets obtained in the experimental examples according to the present invention are the same as those of the conventional compression molding in Comparative Example 2. The magnetic force was 68% higher than that of the isotropic magnet according to Example 1 and 29% higher than the anisotropic magnet obtained by the conventional extrusion method in Comparative Example 1.

[0026]

As described above, according to the present invention, when a magnetic powder is extrusion-molded to produce a cylindrical anisotropic magnet, a pole magnet made of a permanent magnet and an auxiliary magnet are provided in a cylindrical molding hole. By combining the above, it becomes possible to generate a magnetic field necessary and sufficient for the orientation of the magnetic particles, and it is possible to favorably perform the orientation treatment. In addition, as described above, it becomes possible to fix the orientation state while the orientation treatment is being performed well, eliminating the deficiency of conventional extrusion molding, and moreover, the performance equal to or better than that of compression molding. The cylindrical anisotropic magnet can be mass-produced easily and inexpensively.
Further, according to the present invention, it is possible to cope with the miniaturization of the magnet, and to reduce the size, and it is possible to expand the manufacturable range by extrusion molding of the small magnet.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of an apparatus for manufacturing a cylindrical anisotropic magnet according to the present invention.

FIG. 2 is a cross-sectional front view of a main part of the manufacturing apparatus according to the embodiment.

FIG. 3 is an explanatory diagram showing the relationship between the temperature of the kneaded material and the orientation state in the magnet manufacturing process.

FIG. 4 is an explanatory diagram of a basic experiment example for determining the arrangement configuration of magnetic field generating means.

FIG. 5 is a magnetic force characteristic diagram according to the basic experiment example.

6A to 6C are magnetic force characteristic diagrams of magnets obtained in an experimental example and a comparative example according to the present invention.

FIG. 7 is a perspective view of unit crystal particles of a ferrite magnet.

8A and 8B are explanatory views of a radial anisotropic magnet and a magnetizing method thereof.

9A and 9B are explanatory views of a polar anisotropic magnet and a magnetizing method thereof.

FIG. 10 is a perspective view of a cylindrical anisotropic magnet.

11 (a) and (b) are explanatory views showing disorder of orientation during extrusion molding.

12A and 12B are explanatory views showing the alignment state in a magnetic field and the alignment disorder after magnetization.

13 (a) and 13 (b) are explanatory views showing the alignment state in a magnetic field and the alignment disorder after magnetization.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Extruder discharge port 2 Introducing member 3 Mold 4 Heating coil 5 for heat retention 5 Sizing pipe 6 Prolong 7 Core 8 Magnetic field generating means 8a Pole magnet 8b Auxiliary magnet 8c Yoke 9 Cooling means 9a Cooling member 9b Water hole h Cylindrical molding hole

Claims (2)

[Claims] 1. A molding die having a cylindrical molding hole is provided at a discharge port of an extruder for extruding a kneaded material of magnetic powder and a binder heated to 60 ° C. to 90 ° C., and the molding die is arranged around the molding die. In a device for producing a cylindrical anisotropic magnet by extruding the kneaded material in a state in which a magnetic field is generated in the cylindrical forming hole by the magnetic field generating means, a plurality of magnetic field generating means are provided around the cylindrical forming hole. Pole magnets consisting of individual permanent magnets are arranged such that both poles are in the radial direction and the inner poles of adjacent pole magnets are different from each other, and between the adjacent pole magnets, Auxiliary magnet consisting of permanent magnet of the same material, so that both poles are in the circumferential direction,
And each pole is arranged so as to be the same pole as the inside pole of the adjacent pole magnet, and a ring-shaped yoke made of a ferromagnetic material is arranged on the outer circumference of those magnets. Anisotropic magnet manufacturing equipment. 2. The molding die comprises a cylindrical sizing pipe made of a non-magnetic material and a prolong, which are continuously provided, and a core is arranged inwardly of the sizing pipe and the prolong. 2. The apparatus for manufacturing a cylindrical anisotropic magnet according to claim 1, wherein the magnetic field generating means is arranged on the outer circumference of the cylindrical anisotropic magnet, and the cooling means is arranged in close contact with the outer peripheral surface of the prolong and the side surface of the magnetic field generating means.