JPH05166655A - Manufacture of resin-bonded magnet - Google Patents

Abstract

PURPOSE:To manufacture an anisotropic resin-bonded magnet, by using a simplified manufacturing method, wherein a drop in its magnetic performance is suppressed. CONSTITUTION:A magnet composition which has oriented the mixture of an Sm-Co-based magnet with a thermoset resin in a magnetic field and which has temporarily molded the mixture to be a block shape is further extrusion- molded, and an anisotropic magnet is formed. Consequently, an anisotropic resin-bonded magnet which has suppressed a drop in its magnetic performance can be manufactured by a simplified manufacturing method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a resin-bonded magnet.

[0002]

2. Description of the Related Art Among conventional molding methods for resin-bonded anisotropic magnets, the following molding method is used as a method using an extruder. One is a method in which a pellet-shaped magnet composition is fed to a screw extruder or a ram extruder to form a melt, which is then oriented at the tip of a mold while being narrowed down to a predetermined shape and then molded. The other is a method in which a magnet composition which is anisotropically formed into a block shape and is temporarily formed is fed to a ram extruder, and the semi-molten state is narrowed down to a predetermined shape and oriented again at the tip of the die to form a shape. .. In all of these methods, an anisotropic magnetic field is obtained by orienting magnet powder by applying an orienting magnetic field when the magnet is molded into a final shape. Unlike the other molding methods such as the compression molding method and the injection molding method, this extrusion molding method is a continuous molding type production system and therefore has excellent productivity. Moreover, it is possible to manufacture a magnet having a thin shape, a long shape, and the like.

[0003]

However, the above manufacturing method has the following problems. That is, when orienting the magnet composition during molding, equipment for orienting is required, and the mechanism of the magnetic circuit becomes complicated depending on the shape and size of the molded product. In particular, in the case of taking a large number of pieces, it is difficult to obtain a sufficient orientation magnetic field.
Further, when a kneading step is involved in the production of the magnet composition, the thermal influence becomes large, and thus the thermal deterioration of the magnet powder cannot be avoided. Further, when a magnet is manufactured using an organic resin having a high melting temperature and magnet powder which is easily affected by heat, the magnet powder is thermally deteriorated during the manufacturing process, so that the magnetic performance of the molded magnet is deteriorated.

The present invention solves such a problem, and an object thereof is to provide an anisotropic resin-bonded magnet which suppresses deterioration of magnetic performance by a simplified manufacturing method. is there.

[0005]

A method for producing a resin-bonded magnet according to the present invention is a method for producing a resin-bonded magnet in which rare earth magnet powder is bound by an organic resin, wherein a transition metal mainly composed of a rare earth metal and cobalt is used. An anisotropic magnet is obtained by orienting a mixture of magnet powder and thermosetting resin in a magnetic field, preforming by warm compression molding, and further molding by using a ram extruder. ..

[0006]

According to the above-mentioned manufacturing method of the present invention, a mixture of a magnet powder composed of a transition metal mainly composed of a rare earth metal and cobalt and a thermosetting resin is oriented in a magnetic field and temporarily molded by a warm compression molding method. By using the method, the anisotropically formed block is obtained. Since this manufacturing method is a simple pressing mechanism, the magnetic circuit for orientation has a simple structure, and the orientation of the magnet composition can be easily performed. Here, since the thermosetting resin has a low melting temperature, the step of binding the magnet powder and the resin by warm compression molding and the extrusion molding step can be carried out in a low temperature process, so that the thermal effect on the magnet powder is small. Furthermore, as magnet powder, S
By using the m-Co system, a magnet that is thermally stable and has high heat resistance can be manufactured. The anisotropically magnetized composition is fed into a ram extruder and extruded in a semi-molten state to extrude the magnetized composition while maintaining the anisotropy of the magnetized composition. It is possible to obtain magnets, and even when multiple magnets with a complicated shape such as straw shape are taken, it is only divided into extruded pieces that are oriented in advance, so there is little variation in performance and there is some variation. It is possible to manufacture a magnet having directionality. (Here, the semi-molten state refers to a state in which the magnet composition that has been temporarily molded is extruded by a plug flow.) Therefore, even if the process of orienting by a magnetic circuit is omitted during extrusion molding, some anisotropy will occur. It is possible to realize the possessed magnet with a simplified manufacturing method without variation in performance.

[0007]

EXAMPLES The magnet powder used in the present invention is a magnet powder having a basic composition of a rare earth metal and a transition metal mainly containing cobalt. The thermosetting resin may be phenol, epoxy, polyimide or the like. A mixture of these magnet powders and a thermosetting resin is oriented in a magnetic field and temporarily molded into a block shape by a warm compression molding method. Next, this block-shaped magnet composition is fed to a ram extruder and extruded in a semi-molten state to form a straw-shaped anisotropic magnet.

A more detailed embodiment will be described below.

(Example 1) A magnet powder and a phenol resin having a composition of Sm (Co _0.672 Cu _0.080 Fe _0.22 Zr _0.028 ) _8.35 were mixed with the magnet powder 60.
Weigh the mixture so that it is 40% by volume of the resin and 40% by volume of the resin. Then, a 15 kOe orienting magnetic field is applied to perform warm compression molding to temporarily form an anisotropic block-shaped magnet composition. The molding pressure is 1.5 t / cm ² . Next, this block-shaped magnet composition is fed to an extrusion molding machine and extruded by ram extrusion molding while maintaining the anisotropy of the semi-molten block by ram extrusion molding. Molding 1
A single piece and a large number of six pieces were taken. Extrusion pressure is 50
It is kg / cm ² . The molded magnet has a central angle of 115 ° and a wall thickness of 1.
It is a straw-shaped magnet with an outer diameter of 2 mm and an outer diameter of 5 mm.

As a comparative example, the above-mentioned anisotropic block-shaped magnet composition was fed to a ram extruder and the mold temperature was changed.
It was extruded by ram extrusion molding while maintaining the anisotropy of the semi-molten block at 180 ° C, and was further re-oriented by applying an orientation magnetic field of 15 kOe using a magnetic circuit at the time of shaping to perform shaping. As for molding, 1 piece and 6 pieces were taken in the same way. The magnet shapes were the same.

Table 1 shows the performance of anisotropic magnets and the facility of equipment for orientation when a single piece and a large number of six pieces are taken.

[0012]

[Table 1]

As is clear from Table 1, according to the steps used in the present invention, since the orientation is not performed at the time of molding into the final shape, the performance is inferior to that of the conventional method, but due to the orientation, The mechanism can be simplified, and in particular, when a large number of 6 pieces are taken, a value close to the performance of the magnet formed by the conventional manufacturing method is obtained. It is difficult to control the flow of the magnetic flux uniformly in one direction due to the influence of the shape of the orientation part of the mold with anisotropic magnets by the conventional manufacturing method used for comparison. It is also difficult to obtain a magnetic field, and the performance of each anisotropic magnet deteriorates and variations occur. As described above, by using the manufacturing method of the present invention, when performing multi-cavity molding, it is possible to simplify an anisotropic extruded magnet that has the same level of performance as the anisotropic magnet manufactured by the conventional manufacturing method and has little variation in position. It can be realized by a simplified manufacturing method.

(Example 2) A magnet powder and a phenol resin having a composition of Sm (Co _0.672 Cu _0.080 Fe _0.22 Zr _0.028 ) _8.35 were used as the magnet powder 60.
Weigh the mixture so that it is 40% by volume of the resin and 40% by volume of the resin. Then, a 15 kOe orienting magnetic field is applied to perform warm compression molding to temporarily form an anisotropic block-shaped magnet composition. The molding pressure is 1.5 t / cm ² . As a comparative example, the same molding was performed using a thermoplastic polyamide resin. The molding temperature was 180 ° C at which the polyamide resin was in a molten state. As another comparative example, a magnet powder having a composition of Nd ₁₄ (Fe _0.95 Co _0.05 ) _80.5 B _5.5 and a phenol resin or a polyamide resin were weighed so that the magnet powder was 60 vol% and the resin was 40 vol%. Similar molding was performed using the mixture. The molding temperature is a temperature that depends on each resin and is the same as the above conditions. Next, these block-shaped magnet compositions were fed to a ram extruder, and the mold temperature was 180 ° C. for the magnet composition using the phenol resin, and 200 ° C. for the magnet composition using the polyamide resin to obtain a semi-molten state. Extrusion is performed while maintaining the block anisotropy. The extrusion pressure is 50 kg / cm ² .
The molded magnet has a central angle of 115 °, a wall thickness of 1.2 mm, and an outer diameter of 5 mm.
This is a straw-shaped magnet, and 6 pieces were taken.

Table 2 shows the thermal deterioration of the magnetic performance during the molding process of each magnet.

[0016]

[Table 2]

The thermal deterioration of the magnetic performance was expressed by the ratio of the coercive force (iHc) _pm of the molded magnet and the coercive force (iHc) _m of the magnet powder. As is clear from Table 2, the anisotropic extruded magnet produced by using the Sm-Co based magnet powder of the present invention and the thermosetting resin hardly causes thermal deterioration of the magnetic performance in the molding process.
The extruded magnet using the thermoplastic resin used for comparison has a high temperature in the molding process, so that the magnetic performance is deteriorated due to thermal influence. In addition, extruded magnets using Nd-Fe-B system magnet powder are susceptible to thermal effects on the magnet powder itself, resulting in deterioration of magnetic performance. As described above, the anisotropic extruded magnet with suppressed deterioration of magnetic performance can be manufactured by the manufacturing method of the present invention.

[0018]

As described above, by using the manufacturing method of the present invention, it is possible to manufacture an anisotropic resin-bonded magnet in which deterioration of magnetic performance is suppressed by a simplified manufacturing method. These can be widely used for stepping motors, DC motors, sensors, etc., which are required to be small and precise and have high performance.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number in the agency FI Technical indication location H01F 7/02 B 7135-5E (72) Inventor Masaaki Sakata 3-3-5 Yamato, Suwa City, Nagano Prefecture No. Seiko Epson Co., Ltd. (72) Inventor Koji Akioka 3-3-5 Yamato, Suwa City, Nagano Prefecture No. 3 Seiko Epson Co., Ltd. (72) Inventor Toshio Ikeda 1-20-8 Higashionuma, Sagamihara City, Kanagawa Prefecture (72) Invention Person Naoshi Nanjo 1-9-24 Higashibayashi Sagamihara City, Kanagawa Prefecture (72) Inventor Toshihiro Ichijo 5-25-19 Sagami Ohno Sagamihara City, Kanagawa Prefecture Yuri Heights 101 (72) Inventor Hirotaka Ikejiri 4-13 Ohnodai, Sagamihara City, Kanagawa Prefecture −30

Claims (1)

[Claims] 1. A method for producing a resin-bonded magnet in which rare earth magnet powder is bonded by an organic resin, wherein a mixture of magnet powder made of a transition metal mainly containing rare earth metal and cobalt and a thermosetting resin is oriented in a magnetic field. A method for producing a resin-bonded magnet, comprising temporarily forming by a warm compression molding method, and then forming the anisotropic magnet by using a ram extruder.