JP2016032054A - To rare-earth bond magnet, manufacturing method for the same and motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a rare-earth bond magnet adopting high heat-resistance resin such as polyphenylene sulfide as thermoplastic resin which satisfies a requirement of necessitating antirust processing of magnet powder and neogenesis face occurring suppressing means to avoid deterioration of magnetic characteristics of the rare-earth bond magnet and secular change (deterioration) under the condition that the environmental temperature of the manufacturing process is higher than prior arts.SOLUTION: A weather resistance coating 2 is formed on rare-earth magnet powder 1, and then a sliding coating is formed on the weather resistance coating 2 to prepare sliding magnet powder 4. The coating portion of the rare-earth magnet powder 1 contains weather resistance (antirust material) as a main component of the coating layer of the lowermost layer on a side contacted with the surface of the rare-earth magnet powder and sliding material as a main component of the coating layer of the uppermost layer of the coating portion.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rare earth bond magnet, a method for producing a rare earth bond magnet, and a motor equipped with a rare earth bond magnet.

  Magnets mounted on motors used for information equipment, home appliances, industrial use, automobiles, etc. include ferrite magnets, rare earth sintered magnets, and rare earth bonded magnets. In particular, when a high power density is required, a rare earth magnet is used. Rare earth sintered magnets currently have the highest maximum energy product and contribute to miniaturization and high output of equipment, although there are problems such as cracking, chipping and rusting.

  On the other hand, a rare-earth bonded magnet is generally a resin-bonded magnet in which Nd—Fe—B magnet powder containing Nd, which is a rare earth, is hardened with a resin. Rare earth-based bonded magnets contain a resin component, so there are fewer magnet components and lower magnetic properties than rare earth sintered magnets, but there are fewer problems of cracking and chipping like rare earth sintered magnets, and There is no need for post-processing, and in general, it contributes to high output of small motors such as information equipment and home appliances in which shape flexibility such as long, cylindrical, cylindrical and uneven thickness works effectively.

  In recent years, due to the progress of EV and HEV in automobiles, there are many parts that change from hydraulic to electric in addition to the main motor that powers automobiles, and the demand for small motors is increasing. Among them, motors such as oil pumps mounted around the engine also have high heat resistance requirements of about 150 ° C due to the ambient temperature and heat generation of the coils in the motor, and are small, high power and high heat resistance rare earths that take advantage of shape flexibility. Development of bonded magnets is required.

  Typical molding processes in the molding process of the manufacturing method of rare earth-based bonded magnets used for such motors are compression molding and injection molding.

  When compression molding is used in the molding process of the rare earth bonded magnet manufacturing method, a composite powder in which magnet powder and thermosetting resin are mixed is compression molded in a cylindrical mold, and then the thermosetting resin is cured. And a bonded magnet. A compact of a rare earth-based bonded magnet by compression molding has good productivity, and a high-density magnet can be produced. As a rare-earth bonded magnet, a magnet by compression molding is widely used.

  On the other hand, when injection molding is used in the molding process of the manufacturing method of rare earth bonded magnets, a composite material composed of magnet powder and thermoplastic resin is melted at a high temperature, poured into a mold, and cooled and solidified into a magnet. Because it is manufactured (compared to compression molding that has only two-dimensional planar shape because of compression in one axis direction), the flexibility of three-dimensional shape can be improved by flexibly changing the shape of the mold. In recent years, technological development has been active because it is possible to expand the range of motor design.

  In the rare-earth bonded magnet and the manufacturing method thereof, there has been a specific problem due to the properties of the magnet powder. The problem due to the properties of this magnet powder is that the magnet powder itself is easily oxidized because the magnet powder is an iron-based magnet alloy containing a rare earth element, and this oxidation reduces the magnetic properties of the rare-earth bond magnet. To do. Therefore, in order not to deteriorate the magnetic characteristics, it is necessary to perform some rust prevention treatment. In other words, the oxidation of the magnet powder can be expressed as rusting of the magnet powder.

  Numerous proposals have been made regarding the anticorrosion treatment of this type of bonded magnet. In the following patent documents, etc., it is possible to prevent rust prevention treatment of magnet powder, rust prevention treatment of finished rare earth bonded magnets, and magnet powder and rare earth bonded magnet finished products. The method of applying rust treatment is described.

  For example, in Patent Document 1 and the like, a magnet powder made of an iron-based magnet alloy containing a rare earth element having a coating containing iron phosphate and a rare earth metal phosphate formed on its surface, and thermoplastic or thermosetting as a resin binder. A resin-bonded magnet composition containing a resin is described. Furthermore, this document also describes the use of a resin-bonded magnet composition in which a tetraalkoxysilane compound is blended by an integral blend method.

  In addition, in order to suppress the oxidation of the magnet powder, the powder surface is subjected to chemical conversion treatment such as phosphate treatment or chromate treatment (Patent Document 2, etc.), and zinc or aluminum is deposited (Patent Document). 3), forming a polymer film (Patent Document 4 etc.), metal plating (Patent Document 5 etc.), when coating a magnetic alloy powder, add phosphoric acid into the grinding solvent, There is a method of generating rare earth or iron phosphates on the surface of the alloy powder (Patent Document 6, etc.).

  However, even if the rust prevention treatment as described above is performed, the following problems are included. The problem is caused by the shape of the magnet powder. Since this type of magnet powder is not granular, it is an irregularly shaped flake having a thickness of 20 to 30 μm and a diagonal direction of 50 to 150 μm. Due to the process in which the mechanical load is applied, the magnet powder is easily broken into smaller pieces.

  This crushed piece has a new surface with exposed magnet powder dough. The dough appearing on the new surface reacts with oxygen in the atmosphere and gradually oxidizes. In this way, among the materials constituting the rare earth bond magnet, the magnet powder is oxidized, so that the magnetic characteristics of the rare earth bond magnet change over time (decrease in magnetic characteristic value over time). .

  Therefore, in a case where only a phosphoric acid film is applied as in Patent Document 7, an excessive force is applied to the magnet powder at a high pressure during compression molding, and the magnet powder is crushed and the phosphoric acid film is applied. A new surface is generated, and oxidation proceeds from the new surface. For this problem, as in Patent Document 8, etc., after compression molding a mixed powder composed of a magnet powder and a resin subjected to a phosphoric acid-based coating as an antirust treatment, the compression molded body is subjected to phosphoric acid treatment again. By dipping in the liquid and infiltrating the inside of the compression molded body, the new surface generated by crushing the magnet powder during compression is treated with weather resistance, and heat resistance is increased. It is noted that a coating is applied.

  Even if the above problem is solved, it is presumed that the new surface of the magnet powder generated during the manufacturing process starts to be oxidized immediately after the new surface is generated, and the oxidation gradually proceeds to the deep part of the magnet powder. In addition, even if the entire outer surface of the rare earth bond magnet is covered with a coating such as a resin, there are not a few pinholes in the coating, so oxygen and magnet powder in the atmosphere can be passed through the pinhole. It is speculated that the new surface comes into contact with the new surface and oxidizes. In this way, it is presumed that the magnetic characteristics of the rare-earth bonded magnet change with time (decrease in magnetic characteristics) due to the oxidation of the new surface of the magnet powder and the progress of the oxidation of the magnet powder to the deep part.

  Now, in order to solve the above-mentioned problems and to further improve the performance of rare earth bonded magnets, there is a new problem when using polyphenylene sulfide, a thermoplastic resin that is expected to have high heat resistance For confirmation, a rare earth-based bonded magnet sample was created in the following prototype example.

(Prototype example)
The Nd-Fe-B magnet powder MQP-14-12 manufactured by Magnequench manufactured by the quenching thin plate method is subjected to a phosphate coating of a weather resistant coating (rust preventive coating), and Shin-Etsu Chemical It was mixed with 3-glycidoxypropyltrimethoxysilane, which is a silane coupling agent, and further mixed with polyphenylene sulfide thermoplastic resin powder manufactured by DIC Corporation. This mixture was put into a biaxial extrusion kneader to produce a composite material. The apparatus temperature during kneading was 310 ° C.

The obtained composite material was injection molded at a temperature of 300 ° C. under an injection pressure of 4 ton / cm ² to produce a cylindrical magnet having a diameter of 5 mm and a height of 5 mm. Magnetic properties were measured with a magnetometer.

  The coercive force Hcb of the bonded magnet with only the weather-resistant film of this prototype is measured at 350 kA / m, and it is confirmed that the coercive force Hcb is reduced by 25% with respect to 470 kA / m of the original coercive force Hcb of MQP-14-12. It was done.

  Next, the reason why the coercive force Hcb of the rare earth-based bonded magnet employing the thermoplastic resin polyphenylene sulfide of this prototype is lowered will be discussed.

  First, in the case of the above heat-resistant resin such as polyphenylene sulfide, since the melting point is about 280 ° C., the temperature of the material in the kneading step and the injection molding step is as high as 300 to 350 ° C. Unlike compression molding of a thermosetting resin that is usually molded at normal temperature, injection molding of a thermoplastic resin undergoes a molding process at a very high temperature (300 to 350 ° C.). Moreover, the temperature at the time of kneading | mixing magnet powder and a thermoplastic resin will also pass through the refining process at very high temperature (300-350 degreeC) similarly.

  Naturally, the magnet powder is crushed by friction between the screw and wall surface of the kneading extruder used in the kneading step and the magnet powder. And the new surface produced by this crushing is oxidized more excessively (to the deep part of the magnet powder) than in the past because both the kneading process and the injection molding process are in a high heat environment of 300 ° C. or more, and the squareness and coercive force are increased. It was speculated that the magnetic characteristics such as

  In addition, as described above, the oxidative deterioration of the new surface of the magnet powder caused by crushing occurs in a high-temperature environment of 300 ° C. or higher, so that it is estimated that the oxidation proceeds more deeply than in the past. Therefore, even if the entire outer surface of the rare earth bond magnet in the process including the injection molding of this prototype is covered with a coating film such as a resin, the oxidation of the magnet powder is too advanced, It was also speculated that the effect as in the case of compression molding of a thermosetting resin molded at room temperature is not exhibited.

JP 2011-146416 A JP-A 64-14902 JP-A-64-15301 JP-A-4-257202 Japanese Patent Laid-Open No. 7-142246 JP 2002-8911 A Japanese Patent Laid-Open No. 2003-7521 JP 2005-268352 A

  In the manufacturing process of rare earth-based bonded magnets employing high heat-resistant resin such as polyphenylene sulfide of thermoplastic resin, the environmental temperature of the manufacturing process is higher than before, and the magnetic property characteristics of rare earth-based bonded magnets are reduced. In order to avoid changes (deterioration) over time, rust prevention treatment of magnet powder is essential, and there is a new need for some new surface generation suppression means that suppresses generation of new surface due to crushing of magnet powder. Was raised.

  In a first aspect of the present invention, there is provided a rare earth-based bonded magnet including a rare earth-based magnet powder and a resin component, wherein the rare earth-based magnet powder includes a coating portion that covers a surface of the rare earth-based magnet powder. The main component of the lowermost coating layer on the side in contact with the surface contains a weather resistant material (rust preventive material), and the main component of the uppermost coating layer of the coating portion contains a slidable material as a means for suppressing the generation of new surfaces. It is a rare earth bond magnet.

  A second invention is the rare earth bond magnet according to the first invention, wherein the weather resistant material contains phosphate, and the slidable material as the new surface generation suppressing means contains nickel and boron.

  According to a third invention, in the first invention, the weather-resistant material contains a phosphate, and the slidable material as a new surface generation suppressing means contains nickel and a fluorine-based polymer compound. It is.

  A fourth invention is the rare earth bond magnet according to the first invention, wherein the weather resistant material includes phosphate, and the slidable material as the new surface generation suppressing means includes manganese phosphate.

  A fifth invention is the rare earth-based bonded magnet according to the first invention, wherein the weather-resistant material contains phosphate and the slidable material contains molybdenum disulfide.

  A sixth invention is an electric motor including the rare earth bond magnet of the first to fifth inventions.

  A seventh invention is a method for producing a rare earth-based bonded magnet using a coated rare-earth magnet powder in a method for producing a rare-earth bonded magnet, wherein the lowermost coating layer of the coated portion of the coated rare-earth magnet powder is provided. This is a method for producing a rare earth-based bonded magnet, which includes a weather resistant material as a main component and a slidable material as a new surface generation suppressing means as a main component of the uppermost coating layer of the coating portion.

  The eighth invention is a method for producing a rare earth based bonded magnet using the coated rare earth based magnet powder having an upper limit value of the dynamic friction coefficient of 0.1 as the new surface generation suppressing means in the seventh invention.

  A ninth invention comprises the step of using a kneading extruder in the seventh invention, comprising a step of using a kneading extruder for mixing a coated rare earth magnet powder and a resin component and processing it into a resin composition for a bonded magnet, Is a method for producing a rare earth-based bonded magnet having a screw coated with a slidable film as a new surface generation suppressing means and a casing inner surface.

  A tenth invention includes a step of using a kneading extruder for mixing the coated rare earth magnet powder and the resin component into a bonded magnet resin composition in the seventh invention, and further comprising the kneading An extruder is a method for producing a rare earth-based bonded magnet that fills an inert gas therein.

  The eleventh aspect of the invention is the seventh aspect of the invention, in which the step of kneading and extruding for mixing the coated rare earth magnet powder and the resin component in an inert gas atmosphere and processing it into a bonded magnet resin composition It is a manufacturing method of the rare earth type bonded magnet containing this.

  A twelfth aspect of the invention is a method of manufacturing a rare-earth bond magnet according to the seventh aspect of the invention, wherein the weather resistant material includes phosphate, and the slidable material as a new surface generation suppressing means includes nickel and boron. is there.

  A thirteenth invention is the rare earth bond magnet according to the seventh invention, wherein the weather resistant material contains phosphate, and the slidable material as the new surface generation suppressing means contains nickel and a fluorine polymer compound. It is a manufacturing method.

  A fourteenth aspect of the invention is a method for manufacturing a rare earth-based bonded magnet according to the seventh aspect of the invention, wherein the weather resistant material contains phosphate, and the slidable material as the new surface generation suppressing means contains manganese phosphate. is there.

  A fifteenth aspect of the invention is a method for producing a rare earth-based bonded magnet according to the seventh aspect of the invention, wherein the weather resistant material contains a phosphate, and the slidable material as a new surface generation suppressing means contains molybdenum disulfide. is there.

  A sixteenth aspect of the invention is a method for producing a rare earth-based bonded magnet according to the ninth aspect of the invention, wherein nickel and boron are included in the slidable film of the kneading extruder as the new surface generation suppressing means.

  A seventeenth aspect of the invention is a method for producing a rare earth-based bonded magnet according to the ninth aspect of the invention, wherein the sliding film of the kneading extruder as the new surface generation suppressing means contains nickel and a fluorine-based polymer compound.

  An eighteenth aspect of the invention is a method for producing a rare earth-based bonded magnet according to the ninth aspect of the invention, wherein manganese phosphate is included in the slidable film of the kneading extruder as the new surface generation suppressing means.

  A nineteenth aspect of the invention is a method for producing a rare earth-based bonded magnet according to the ninth aspect of the invention, wherein the slidable film of the kneading extruder as the new surface generation suppressing means contains molybdenum disulfide.

  The present invention relates to a rare earth bonded magnet composed of a rare earth magnet powder and a resin component, and the surface of the rare earth magnet powder is coated with a weather-resistant film, and further, slidability as a means for suppressing generation of a new surface. A rare-earth bonded magnet characterized by being coated with a film.

  According to the present invention, in the step of kneading the magnet powder and the resin or the step of injection molding, the sliding film on the outer periphery of the rare earth magnet powder is kneaded or injection molded with the screw or wall surface and the magnet powder, or between the magnet powders. In order to reduce the friction of the magnet, disperse the pressure applied to the magnet powder, suppress the crushing of the magnet powder, and minimize the generation of new surfaces, the magnet powder is protected by a weather-resistant film, and is heated at the time of kneading and injection molding. It is possible to provide a high heat-resistant bonded magnet that suppresses oxidative degradation due to the heat.

  Moreover, the rare earth-based bonded magnet is characterized in that the upper limit value of the dynamic friction coefficient of the slidable film as a new surface generation suppressing means for coating the rare earth-based magnet powder is 0.1, so that the effect of suppressing crushing is obtained. Can be increased.

  Furthermore, the screw and the inner surface of the kneading extruder for mixing the rare earth magnet powder and the resin component into a bonded magnet resin composition were coated with a slidable coating as a new surface generation suppressing means. By using the rare earth bond magnet characterized by the above, particularly, friction between the screw and the wall surface during kneading and injection molding and the magnet powder can be reduced, and crushing of the magnet powder can be suppressed.

  Furthermore, by mixing the rare earth magnet powder and the resin component and processing the resin composition for a bond magnet into a kneading extruder filled with an inert gas, a rare earth bond magnet characterized by being prepared, It is possible to reduce the probability of oxygen binding to the new surface of the crushed powder, which could not be prevented by the above-described suppression of pulverization of the magnet powder, by making the state of low oxygen.

  Moreover, by making the motor characterized by mounting the rare earth-based bonded magnet, the original magnetic properties of the magnet powder can be exhibited, the output density as a motor product can be increased, and long-term high temperature Environmental reliability is also obtained.

Schematic diagram of slidable magnet powder The figure which shows the mixed state of slidable magnet powder and thermoplastic resin powder Diagram showing the outline of the internal structure of the kneading extruder Schematic diagram enlarging the inside of a kneading extruder when kneading slidable magnet powder Schematic diagram of forces applied to wall surfaces, screws and magnet powders in a kneading extruder Schematic diagram of material alignment by sliding between slidable magnet powders Schematic diagram of slidable coating on wall and screw of extrusion kneader Schematic diagram of bonded magnet using slidable magnet powder Schematic diagram of weather-resistant magnet powder Schematic diagram enlarging the inside of a kneading extruder when kneading weather-resistant magnet powder Schematic diagram of crushed state and oxide film of weather-resistant magnet powder Schematic diagram of bonded magnet using weather-resistant magnet powder External view of a rotor in which the bonded magnet of the present invention is mounted on a magnet-embedded core External view of a motor with a magnet embedded rotor

The present invention will be described below with reference to the drawings and tables. The present invention is not limited to the following embodiments and examples.
(Embodiment)
FIG. 1 shows a slidable magnet powder 4 obtained by applying a weatherable film 2 to a rare earth magnet powder 1 and further applying a slidable film as a new surface generation suppressing means. The film portion of the rare earth magnet powder 1 contains a weather-resistant material (rust preventive material) as a main component of the lowermost film layer on the side in contact with the surface of the rare earth magnet powder, and the outermost portion of this film portion. You may employ | adopt the structure which contains a slidable material in the main component of the upper film layer.

  The slidable magnet powder 4 and the thermoplastic resin powder 5 were mixed to obtain a mixed state shown in FIG. This mixture is put into a kneading extruder 6 heated to a high temperature as shown in FIG. 3 and kneaded.

  In FIG. 4, the schematic diagram which expanded the inside of the kneading extruder 6 at the time of slidable magnet powder kneading | mixing is shown. As shown in FIG. 4, the slidable magnet powder 4 and the thermoplastic resin powder 5 are arranged in an extrusion kneader, and the thermoplastic resin powder 5 melted in the process of flowing the material spirally as the screw 8 rotates. The slidable magnet powder 4 is kneaded inside. During the kneading, a force such as a force 10 received from the screw and the wall surface of the casing as shown in FIG. 5 and a force 11 received by friction between the magnet powders is applied to the slidable magnet powder.

  However, since the slidable magnet powder 4 of the present invention is coated with a slidable film having a low friction coefficient on the outermost periphery of the magnet powder, the force received from the screw 8 and the wall surface 7 of the casing and the friction between the magnet powders. Disperses the force received by, and suppresses crushing of magnet powder.

  Therefore, as shown in FIG. 6, the slidable magnet powder 4 disperses the force received from the screw 8 or the wall surface 7 of the casing, and flows so that the long axis of the slidable magnet powder 4 is aligned in the flow direction, An alignment state 12 in the flow direction is formed by sliding of the slidable magnet powder.

  In addition, as shown in FIG. 7, when the slidable film 13 and the slidable film 14 are provided as means for suppressing generation of a new surface on the wall surface 7 and the screw 8 of the casing of the extrusion kneader, the slidable magnet powder 4 The effect of pressure dispersion can be further enhanced.

  Incidentally, the slidable film 13 and the slidable film 14 as means for suppressing the generation of new surfaces on the casing wall 7 of the extrusion kneader and the screw 8 are, for example, electroless nickel boron plating or electroless nickel as commercial names. A film known as PTFE composite plating, a film containing nickel and boron having the same performance, or a film containing nickel and a fluorine-based polymer compound may be used. Alternatively, a film containing manganese phosphate or a film containing molybdenum disulfide may be used.

  Furthermore, when the material flow space 9 of the extrusion kneader is filled with an inert gas, even if the sliding effect of the slidable magnet powder 4 is insufficient and the magnet powder is crushed, the oxygen concentration is reduced, It is possible to minimize the deterioration of the magnet powder due to oxygen.

  The bonded magnet produced as described above takes the form of the bonded magnet 15 using the slidable magnet powder shown in FIG. 8, and there is no crushing of the magnet powder, and the squareness and coercive force due to oxidation are not affected. A high-performance bonded magnet with no deterioration in magnetic properties.

  Furthermore, since the motor equipped with the bonded magnet 15 using the slidable magnet powder does not deteriorate the squareness and the coercive force, it is possible to increase the generated magnetic flux at the operating point of the magnet, and the output of the motor. The density can be increased, and further, long-term stability in a high-temperature environment is also achieved since the magnet powder is crushed to a minimum.

  Next, a comparison between the above-described prototype and the present invention will be briefly described. In the above-described prototype, a rare-earth bonded magnet was prepared by injection molding using a magnet powder having only a weather-resistant film and not having a slidable film, and a thermoplastic resin. FIG. 9 shows a schematic diagram of the weather-resistant magnet powder 16. This is a simple structure in which a rare earth magnet powder 1 is provided with a weather resistant coating 2. FIG. 10 shows an enlarged schematic diagram of the inside of the kneading extruder during kneading of the weather-resistant magnet powder.

  Similarly to the kneading of the slidable magnet powder 4, the magnet powder receives an external force from the wall surface 7 of the casing of the extrusion kneader, the screw 8, or from friction between the magnet powders. However, since there is no slidable film on the outermost peripheral surface of the magnet powder, the pressure due to friction cannot be dispersed, and the external force is directly received by the magnet powder itself. As a result, the flowing material is such that the magnet powder is aligned with the major axis in the flow direction 11a, as in the case of the wall surface 7 of the casing 7 and the screw 8 and the magnet powder crushing state 17 caused by friction between the magnet powders. However, the magnet powder is crushed, and the oxide film 18 of the new surface generated by the crushing is formed by the processing temperature for melting the thermoplastic resin, and the oxidation proceeds to the deep part of the magnet powder.

  The rare earth bonded magnet of the prototype manufactured as described above takes a form like the bonded magnet 19 using the weather-resistant magnet powder shown in FIG. 12, and the crushed surface of the magnet powder is oxidized, and the squareness and coercive force are increased. The result is a rare earth bonded magnet with degraded magnetic properties.

  Furthermore, the motor equipped with the rare earth bonded magnet 19 of the prototype example has deteriorated magnetic characteristics such as the squareness and coercive force of the rare earth bonded magnet as compared with the present invention, so the generated magnetic flux at the operating point of the magnet is It is low, and the output density of the motor is also reduced. Furthermore, since the magnetic powder is crushed, long-term stability in a high temperature environment is also impaired.

  The following examples illustrate the present invention in more detail.

  A phosphate film, which is a weather resistant material (rust preventive material), is applied to Nd-Fe-B magnet powder MQP-14-12 manufactured by Magnequench manufactured by a quenching thin plate method. Furthermore, a coating containing nickel and boron, which is a slidable coating as a new surface generation suppressing means, was applied thereon to obtain a magnet powder with improved slidability. This slidable magnet powder was mixed with 3-glycidoxypropyltrimethoxysilane, which is a Shin-Etsu Chemical silane coupling agent, and further mixed with polyphenylene sulfide thermoplastic resin powder manufactured by DIC Corporation. This mixture was put into a biaxial extrusion kneader to produce a composite material. The apparatus temperature during kneading was 310 ° C.

  The film containing nickel and boron, which is a slidable film as a new surface generation suppressing means, is preferably a film having a dynamic friction coefficient of less than 0.1 between the films, but the dynamic friction coefficient between the films is 0.1. Even a slightly larger film is useful. In this example, a well-known electroless nickel boron plating was adopted as a commercial name. However, the present invention is not limited to this, and any film that exhibits an equivalent effect may be used. Absent.

  Moreover, although it is a phosphate membrane | film | coat which is a weather resistant material (rust prevention material), it is not restricted to this, What is necessary is just a membrane | film | coat which exhibits an equivalent effect, and it does not specifically limit.

  The composite material obtained by the above-described manufacturing method is injection-molded to produce a cylindrical magnet having a diameter of 5 mm and a height of 5 mm, and the magnetic properties are measured with a VSM manufactured by Riken Electronics.

  Further, as shown in FIG. 14, a rotor 22 in which a composite material is injection-molded onto a rotor core 20 made of stamped steel sheets stacked in the direction of the rotation axis and a weather-resistant bonded magnet 21 using slidable magnet powder is mounted. Configure.

  The rotor 22 is mounted on a stator composed of a stator core 23 and a stator winding 24 as shown in FIG.

  The phosphate film which is (rust prevention material) is given to the Nd-Fe-B type | system | group magnet powder MQP-14-12 made from a magnetic quench (Magnequench) company produced by the rapid-cooling thin plate method. Furthermore, a film containing nickel and a fluorine-based polymer compound, which is a slidable film as a new surface generation suppressing means, was applied thereon to obtain a magnet powder having improved slidability.

  The film containing nickel and the fluorine-based polymer compound is preferably a film having a coefficient of dynamic friction between the films of less than 0.1, but is useful even if the coefficient of dynamic friction between the films is slightly more than 0.1. It is. Typical examples of the fluorine-based polymer compound include those called polytetrafluoroethylene, polytetrafluoroethylene, and the like. In this example, a well-known electroless nickel PTFE composite plating was adopted as a commercial name. However, the present invention is not limited to this, and any film that exhibits an equivalent effect may be used. It doesn't matter.

  Moreover, although it is a phosphate membrane | film | coat which is a weather resistant material (rust prevention material), it is not restricted to this, What is necessary is just a membrane | film | coat which exhibits an equivalent effect, and it does not specifically limit. The following is the same procedure as in the first embodiment.

  A phosphate film as (rust preventive material) is applied to Nd-Fe-B magnet powder MQP-14-12 manufactured by Magnequench manufactured by a quenching thin plate method, and manganese phosphate is further formed thereon. A magnet powder having a slidability enhanced by applying a coating containing

  The film containing manganese phosphate, which is a slidable film as a new surface generation suppressing means, is preferably a film having a coefficient of dynamic friction between the films of less than 0.1, but the coefficient of dynamic friction between the films is 0.1. Even a slightly larger film is useful. Moreover, the specific aspect of the film is not ask | required.

  Moreover, although it is a phosphate membrane | film | coat which is a weather-resistant material (rust prevention material), it should just be a material which exhibits not only this but an equivalent effect, It does not specifically limit. The following is the same procedure as in the first embodiment.

  The phosphate film which is (rust prevention material) is given to the Nd-Fe-B type | system | group magnet powder MQP-14-12 made from a magnetic quench (Magnequench) company produced by the rapid-cooling thin plate method. Furthermore, a film containing molybdenum disulfide, which is a slidable film as a means for suppressing generation of a new surface, was applied thereon to obtain a slidable magnet powder.

  The film containing molybdenum disulfide, which is a slidable film as a new surface generation suppression means, is preferably a film having a coefficient of dynamic friction between the films of less than 0.1, but the coefficient of dynamic friction between the films is 0.1. Even a slightly larger film is useful. Moreover, the specific aspect of the film is not ask | required.

Moreover, although it is a phosphate membrane | film | coat which is a weather-resistant material (rust prevention material), it should just be a material which exhibits not only this but an equivalent effect, It does not specifically limit. The following is the same procedure as in the first embodiment.
(Evaluation of prototype)
The above comparative example is evaluated. In the prototype, as described above, a phosphate coating is applied to the Nd—Fe—B magnet powder MQP-14-12 manufactured by Magnequench manufactured by the quenching thin plate method. Next, similarly to Example 1, 3-glycidoxypropyltrimethoxysilane, which is a Shin-Etsu Chemical industrial silane coupling agent, is mixed, and further, polyphenylene sulfide thermoplastic resin powder manufactured by DIC Corporation is mixed. This mixture was put into a biaxial extrusion kneader to produce a composite material. The apparatus temperature during kneading was 310 ° C.

The obtained composite material was injection molded at a temperature of 300 ° C. under an injection pressure of 4 ton / cm ² to produce a cylindrical magnet having a diameter of 5 mm and a height of 5 mm. Magnetic properties were measured with a magnetometer.

  The coercive force Hcb of the bonded magnet with only the weather-resistant film of this prototype was measured at 350 kA / m, which was 25% lower than the original coercive force Hcb of MQP-14-12, 470 kA / m.

(Comparison of Example and Prototype)
Table 1 shows the coating composition of the magnetic powders of each example and prototype, the magnetic properties of the bonded magnet, and the output density when mounted on a motor. When mounting on the motor, adjust the difference in magnetic characteristics of the bond magnets of each example and trial example by changing the thickness of the electromagnetic steel plate of the rotor of the motor, and adjust the motor efficiency to approximately the same, The power density was calculated.

  The coercive force Hcb of the bonded magnet with only the weather-resistant film without the slidable film of the prototype is 350 kA / m, which is 25% lower than the original coercive force Hcb = 470 kA / m of MQP-14-12. On the other hand, the magnetic properties of the bonded magnet using the slidable magnet powder having the slidable film of Examples 1 to 4 are substantially equal to the original coercive force Hcb = 470 kA / m of MQP-14-12. Equal value is obtained. The squareness also showed the same tendency, and it was confirmed that the output density of the motor whose efficiency was adjusted to approximately the same could be improved up to 1.2 times.

  It is possible to provide a small-sized, high-power, high-heat resistance rare earth-based bonded magnet and a high-performance motor equipped with it.

DESCRIPTION OF SYMBOLS 1 Rare earth magnet powder 2 Weather-resistant film 5 Thermoplastic resin powder 6 Kneading extruder 7 Wall surface of the casing 8 Screw 9 Material flow space 10 Force received from the screw and the wall surface of the casing 11 Force received by friction between magnet powders 12 Alignment state in flow direction by sliding of slidable magnet powder 16 Weather resistant magnet powder 18 Oxide film of new surface caused by crushing 20 Rotor core 23 Stator core 24 Stator winding

Claims (19)

In the rare earth bond magnet including the rare earth magnet powder and the resin component, the rare earth magnet powder has a coating portion covering the surface thereof, and the coating layer has a lowermost layer on the side in contact with the surface of the rare earth magnet powder. A rare earth-based bond magnet including a weather resistant material as a main component of the coating layer and a sliding material as a main component of the uppermost coating layer of the coating portion. 2. The rare earth bonded magnet according to claim 1, wherein the weather resistant material includes phosphate, and the slidable material includes nickel and boron. 2. The rare earth bond magnet according to claim 1, wherein the weather resistant material includes phosphate, and the slidable material includes nickel and a fluorine polymer compound. 2. The rare earth bonded magnet according to claim 1, wherein the weather resistant material includes phosphate and the slidable material includes manganese phosphate. 2. The rare earth bond magnet according to claim 1, wherein the weather resistant material includes phosphate and the slidable material includes molybdenum disulfide. A motor comprising the rare earth-based bonded magnet according to any one of claims 1 to 5. In the method for producing a rare earth bond magnet, a rare earth bond magnet production method using a coated rare earth magnet powder, wherein the main component of the lowermost coating layer of the film portion of the coated rare earth magnet powder is a weather resistant material And the main component of the uppermost coating layer of the coating portion includes a slidable material, and a method for producing a rare earth bond magnet. 8. The method for producing a rare earth based bonded magnet according to claim 7, wherein the coated rare earth based magnet powder having an upper limit value of a dynamic friction coefficient of 0.1 is used. 8. The method for producing a rare earth based bonded magnet according to claim 7, comprising a step of using a kneading extruder for mixing the coated rare earth based magnetic powder and the resin component to process into a bonded magnet resin composition. The extruder is a method for producing a rare earth-based bonded magnet having a screw coated with a slidable film and an inner surface of a casing. The method for producing a rare earth-based bonded magnet according to claim 7, further comprising the step of using a kneading extruder for mixing the coated rare-earth magnet powder and the resin component and processing it into a resin composition for a bonded magnet, The kneading extruder is a method for producing a rare earth bonded magnet that fills an inert gas therein. 8. A method for producing a rare earth bond magnet according to claim 7, wherein kneading and extrusion for mixing a coated rare earth magnet powder and a resin component in an inert gas atmosphere to process into a bond magnet resin composition. The manufacturing method of the rare earth-based bond magnet including the process to do. 8. The method for manufacturing a rare earth bond magnet according to claim 7, wherein the weather resistant material includes phosphate, and the slidable material includes nickel and boron. 8. The method for producing a rare earth bonded magnet according to claim 7, wherein the weather resistant material includes a phosphate, and the slidable material includes nickel and a fluorine polymer compound. 8. The method for producing a rare earth bonded magnet according to claim 7, wherein the weather resistant material includes a phosphate and the slidable material includes manganese phosphate. 8. The method of manufacturing a rare earth based bonded magnet according to claim 7, wherein the weather resistant material includes phosphate and the slidable material includes molybdenum disulfide. 10. The method for producing a rare earth bond magnet according to claim 9, wherein the sliding film of the kneading extruder includes nickel and boron. The method for producing a rare earth bond magnet according to claim 9, wherein the slidable film of the kneading extruder includes nickel and a fluorine polymer compound. 10. The method for producing a rare earth bond magnet according to claim 9, wherein the slidable film of the kneading extruder includes manganese phosphate. 10. The method for producing a rare earth bond magnet according to claim 9, wherein the slidable film of the kneading extruder includes molybdenum disulfide.

Images