JP2011193621A - Rotor, method for manufacturing the same, and magnet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotor capable of preventing corrosion of a magnet, and also preventing damage of a protective film without executing a put-aside step in inserting a magnetic body into a slot, a method for manufacturing the rotor, and a magnet. <P>SOLUTION: A protective film 12 containing at least fullerene out of the fullerene and DLC (diamond-like carbon) is formed on the surface of the magnetic body 21, and the magnetic body 21 is inserted into the slot 12 of a rotor core 11. A resin film 31 is formed between the inner circumferential surface of the slot 12 and the protective film 22 on the surface of the magnetic body 21. Since the fullerene as the material of the protective film 22 and DLC has lubricity, a resistance in inserting the magnetic body 21 into the slot 12 can be remarkably reduced. A space in the slot 12 is not required to set large for prevention of interference at insertion to the slot 12. Since the fullerene in the protective film 22 disperses in the resin material, the heat resistance of the resin film 31 can be improved. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a magnet provided in a slot of a rotor core, a rotor including the rotor core, and a method of manufacturing the same, and more particularly to improvement of a protective film on a magnet surface.

  In a rotor used for a motor, a magnet is provided in a slot of a rotor core. Among magnets, rare earth permanent magnets have extremely high magnetic properties, and have recently become indispensable for motors for driving automobiles.

  However, since rare earth permanent magnets are susceptible to corrosion by oxygen and moisture, there is a risk of deterioration of magnetic properties. Therefore, in order to prevent corrosion, various protective films are formed on the magnet surface according to various applications. As the protective film, for example, a metal film such as Ni, Cu or Zn having oxidation resistance, a composite film thereof or the like is used (for example, Patent Document 1). In the manufacture of the rotor, a magnetic body having such a protective film formed on the surface is inserted into the slot of the rotor core as a magnet material.

JP-A-60-54406

  However, conventional protective films do not have slipperiness or wear resistance. For this reason, when the magnetic body is inserted, interference with the inner peripheral surface of the slot is likely to occur, which may cause destruction of the protective film. Therefore, the space in the slot is set to be sufficiently larger than that of the magnetic body. In this case, a large clearance is formed between the inner peripheral surface of the slot and the magnetic body after the magnetic body is inserted. For this reason, it is necessary to perform a shifting process in which the magnet is brought into contact with one side of the inner peripheral surface of the slot.

  Therefore, the present invention can prevent the corrosion of the magnet, as well as the rotor that can prevent the destruction of the protective film without performing the shifting process when inserting the magnetic body into the slot, It is an object to provide a method for manufacturing a rotor and a magnet.

  In the rotor manufacturing method of the present invention, a protective film containing at least fullerene of fullerene and DLC is formed on the surface of the magnetic material, and the magnetic material having the protective film is inserted into a slot of the rotor core to protect the surface of the magnetic material. Filled with a liquid resin material between the membrane and the inner peripheral surface of the slot and hardens the resin material to form a resin film, and when forming the resin film, the fullerene is diffused into the resin material It is said.

  In the method for manufacturing a rotor of the present invention, fullerene and DLC used as a material for the protective film have high corrosion resistance, so that corrosion of the magnet can be prevented, and the above material has lubricity. The resistance at the time of inserting the magnetic body into the slot can be greatly reduced. Thereby, destruction of a protective film can be prevented. In addition, it is not necessary to set a large space in the slot to prevent interference during insertion into the slot, and the space in the slot can be set to be slightly larger (approximately equal) than the size of the magnetic material. , A step of shifting after insertion into the slot is not necessary.

  In addition, when the liquid resin material is filled between the magnetic material and the inner peripheral surface of the slot, the fullerene in the protective film diffuses into the resin material, so the heat resistance of the resin film is improved by the radical scavenging action of the fullerene. Can be achieved.

  The rotor manufacturing method of the present invention can use various configurations. For example, the resin material can be cured by heat treatment. In this case, it is preferable to set the temperature in the heat treatment within the range of 60 ° C to 180 ° C.

  The rotor of the present invention is a rotor obtained by the method for manufacturing a rotor of the present invention. That is, the rotor of the present invention includes a rotor core having a slot, a magnet provided in the slot, a protective film formed on the surface of the magnet, and containing at least fullerene among fullerene and DLC, and protection of the surface of the magnetic material. A resin film formed between the film and the inner peripheral surface of the slot, and fullerene is diffused in the resin film.

  The magnet of the present invention is a magnet applied to the rotor of the present invention. That is, the magnet of the present invention is characterized in that a protective film containing at least fullerene of fullerene and DLC is formed on the surface.

  In the magnet of the present invention, since a protective film containing at least fullerene of fullerene and DLC is formed on the surface, it is possible to prevent corrosion as well as applying to the rotor of the present invention. The rotor of the present invention can obtain the above effects (preventing the destruction of the protective film, no need for the shifting process, and improving the heat resistance of the resin film).

  According to the rotor, the rotor manufacturing method, or the magnet of the present invention, it is possible to prevent the corrosion of the magnet, prevent the destruction of the protective film, and improve the heat resistance of the resin film, and to the slot of the magnetic body. This eliminates the need for a shifting process after the insertion.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic structure of the rotor which concerns on one Embodiment of this invention is represented, (A) is a top view of a rotor, (B) is an enlarged top view of the part shown with the broken line X. FIG. It is a SEM photograph of the sample surface which did not use ultrasonic irradiation at the time of fullerene film formation in an example. It is a SEM photograph of the sample surface using ultrasonic irradiation at the time of fullerene film formation in an example.

(1) Configuration of Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of a rotor 1 according to an embodiment of the present invention, in which (A) is a top view and (B) is an enlarged view of a region X in (A). The rotor 1 includes a rotor core 11 having a hole 11A formed at the center. For example, a plurality of slots 12 are formed at equal intervals on the outer peripheral portion of the upper surface of the rotor core 11, and magnets 21 are provided in the slots 12. Magnet 21 is a permanent magnet such as a rare earth permanent magnet. A protective film 22 is formed on the surface of the magnet 21.

  The protective film 22 contains at least fullerene among fullerene and DLC (Diamond-Like Carbon). Specifically, the protective film 22 is a fullerene film made of fullerene or a mixed film of a fullerene film and a DLC film. The DLC film may contain fullerene. In this case, the protective film 22 may be a single layer film of a fullerene-containing DLC film. A resin film 31 made of a thermosetting resin, a UV curable resin, or the like is formed between the inner peripheral surface of the slot 12 and the protective film 22 on the surface of the magnet 21. Since fullerene is diffused in the resin film 31, it has high heat resistance. The resin film 31 is preferably formed on the inner peripheral surface of the slot 12 on the central portion side of the rotor core 11 so that the magnet 21 is positioned on the outer peripheral portion side of the rotor core 11.

Fullerene is a fullerene simple substance, a chemically modified fullerene simple substance subjected to chemical modification, or a mixture thereof. The fullerene itself, for example _{C 60, C 70, C 76} , C 78, C 82, C 84, C 90, C 94, C alone or a mixture thereof, such as ₉₆ and the like. In this case, the fullerene simple substance may contain C ₁₀₀ or higher order fullerene. Examples of the chemically modified fullerene simple substance include simple substances such as C ₆₀ F _x or a mixture thereof. When using the fullerene rolling operation, it is preferable to use C ₆₀ , C ₇₀ , C ₇₆ , C ₇₈ , C ₈₂ , C ₈₄ , C ₉₀ , C ₉₄ , C ₉₆ as the fullerene.

  When a fullerene film is used as the protective film 22, the film thickness is not particularly limited, but is preferably in the range of 0.7 nm to 100 μm. When the film thickness is less than 0.7 nm, it becomes not more than the diameter of the minimum fullerene molecule, so that good insulation cannot be obtained. When the film thickness is more than 100 μm, the fullerene molecules aggregate and form aggregates, so that a uniform film cannot be obtained.

  When a fullerene-containing DLC film is used as the protective film 22, the thickness of the fullerene-containing DLC film is not particularly limited, but is preferably in the range of 1 nm to 100 μm. When the film thickness is less than 1 nm, a uniform film cannot be formed, and good insulating properties cannot be obtained. When the film thickness exceeds 100 μm, the insulating property of the magnetic body 21 (material of the magnet 21) on which the fullerene-containing DLC film is formed becomes high, and electrons generated during the CVD film formation stay and the potential around the magnetic body 21 is increased. Becomes unstable, resulting in non-uniform film quality.

(2) Manufacturing method of embodiment The manufacturing method of the rotor 1 which has the said structure is demonstrated. First, the protective film 22 is uniformly formed on the surface of the magnetic body 21.

  When a fullerene film is used as the protective film 22, the fullerene is coated on the surface of the magnetic body 21 by dissolving the fullerene in a solvent that easily volatilizes to produce a fullerene solvent. The solvent is not particularly limited, but is a nonpolar solvent or a benzene solvent in which fullerene is dissolved. When a nonpolar solvent is used, after the fullerene is dissolved in the nonpolar solvent, the nonpolar solvent may be mixed with a highly volatile polar solvent. When chemically modified fullerene is used as the fullerene, the non-polarity / polarity of the solvent is not limited because the chemically modified fullerene is dissolved in a polar solvent.

  Examples of the fullerene solvent coating method include a spray method, a dripping method, and a dropping method. In this case, an organic substance such as acrylic or epoxy may be mixed with the fullerene solvent in order to improve the adhesion.

When the coating method is used, when the magnetic material 21 is applied to the fullerene bath, for example, the solvent is evaporated at a temperature of 100 ° C. or lower, so that the fullerene molecules are bonded by intermolecular force. _(in the case of _{C 60 fcc,} in the case of _{C 70} hcp) film is formed. In particular, the use of a fullerene molecular bilayer formed when an anion of a fullerene derivative is dissolved in water can effectively prevent the permeation of harmful molecules. In this case, since the fullerene film becomes homogeneous by irradiating the fullerene bath with ultrasonic waves, ultrasonic irradiation is suitable.

  When a mixed film of a fullerene film and a DLC film is used as the protective film 22, the above-described coating method for the fullerene film is combined with the following coating method for the DLC film. In the DLC film coating, the method is not particularly limited, but the thermal CVD method, plasma CVD method, photo CVD method, catalytic chemical vapor deposition method (Cat-CVD method), atmospheric pressure CVD method, vacuum Examples include vapor deposition, ion plating (direct current excitation, high frequency excitation), sputtering (bipolar sputtering, magnetron sputtering, ECR sputtering), laser ablation, ion beam deposition, and ion implantation. Among these methods, a plasma CVD method and an atmospheric pressure CVD method capable of three-dimensional film formation at a low temperature are preferable.

  Since the DLC film is a dense hard carbon film, the permeation of harmful molecules can be prevented. In the mixed film, the harmful molecule can be almost completely suppressed by the DLC film. Further, a synergistic effect of the lubricating action can be obtained by the flatness of the DLC film and the lubricity of the fullerene molecules. In the mixed film, the order in which the fullerene film and the DLC film are formed is not limited. However, in the aspect in which the fullerene film is located on the outside side (the side opposite to the surface of the magnetic body 21), when the resin film 31 is formed, Since the fullerene tends to diffuse, the above embodiment is preferable.

  When a fullerene-containing DLC film is used as the protective film 22, fullerene is contained in the DLC raw material or target in the DLC film coating method described above. Thereby, a fullerene-containing DLC film is obtained.

  The magnetic body 21 having the protective film 22 formed on the surface in this manner is inserted into the slot 12 of the rotor core 11. In this case, since the protective film 22 has high lubricity, interference with the inner peripheral surface of the slot 12 is prevented.

  Next, a resin material is filled between the magnetic body 21 and the inner peripheral surface of the slot 12. At this time, fullerene diffuses into the resin material. Subsequently, since the resin film 31 is formed by curing the resin material, the magnetic body 21 is fixed in the slot 12. Since fullerene is diffused in the resin film 31, the heat resistance of the resin film 31 is improved.

  Here, when a UV resin is used as the resin material, the resin material is cured by ultraviolet irradiation. When a thermosetting resin is used as the resin material, the resin material is cured by heat treatment. In the heat treatment, for example, when a thermosetting resin such as a thermosetting epoxy resin or a silicon resin is used as the resin material, the viscosity of the thermosetting resin is the highest in order to efficiently diffuse the fullerene into the resin material. It is preferable to set the heating temperature to a temperature that falls (for example, a temperature in the range of 60 to 180 ° C.). If the temperature is lower than 60 ° C., the viscosity of the resin material does not decrease, so that the fullerene may be difficult to diffuse. If the temperature exceeds 180 ° C., the curing of the resin material is accelerated. There is a possibility that the diffusion is not sufficiently performed. In particular, since the viscosity of the thermosetting epoxy resin greatly decreases before thermosetting, the fullerene diffuses uniformly in the resin material, and the heat resistance of the resin can be effectively improved.

  Thus, the rotor core 11 with the magnetic body 21 fixed in the slot 12 is set on the magnetized yoke, and a magnetic field is applied there. Thereby, the magnetic body 21 is magnetized and the rotor 1 having the magnet 21 is obtained.

  As described above, in the present embodiment, fullerene and DLC, which are the materials of the protective film 22, have high corrosion resistance. Therefore, the magnet 21 can be prevented from being corroded, and the material has lubricity. The resistance when the magnetic body 21 is inserted into the slot 12 can be greatly reduced. Thereby, destruction of the protective film 22 can be prevented. Further, it is not necessary to set a large space in the slot 12 in order to prevent interference at the time of insertion into the slot 12, and the space in the slot 12 is set to be slightly larger (substantially equivalent) than the size of the magnetic body 21. As a result, the shifting process after insertion into the slot 12 becomes unnecessary. Further, when the liquid resin material is filled between the magnetic body 21 and the inner peripheral surface of the slot 12, the fullerene in the protective film 22 diffuses into the resin material. The heat resistance can be improved.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to specific examples. In the examples, the difference between the slipperiness of the surface of the NdFeB magnetic material coated with various protective films and the coating state of the fullerene film depending on the presence or absence of ultrasonic irradiation was investigated.

(1) Sliding property As the sample 11 of the present invention, an NdFeB magnetic material whose surface was covered with a fullerene film was used. In the preparation of sample 11, fullerene composed of a mixture of C ₆₀ and C ₇₀ was dissolved in 1,24-trimethylbenzene (solubility 17.9 mg / ml), and then the solution was mixed with highly volatile ethanol. A fixed amount of fullerene solvent was prepared. Next, the NdFeB magnetic material was applied to a fullerene solvent bath that had been irradiated with ultrasonic waves, and then heated at 80 ° C. to form a fullerene film on the surface of the NdFeB magnetic material.

  As the reference sample 11, an NdFeB magnetic material whose surface was coated with a DLC film was used. In the production of the sample 12, after the Si underlayer was coated on the surface of the NdFeB magnetic material by sputtering in order to improve the adhesion, a DLC film (film thickness of about 1 μm) was formed by plasma CVD.

  As the sample 12, an NdFeB magnetic material whose surface was covered with a mixed film of a fullerene film and a DLC film was used. In the preparation of the sample 12, a DLC film was formed on the NdFeB magnetic body by the same method as the reference sample 11, and then a fullerene film was formed by the same method as the sample 11.

  As a comparative sample 11, an NdFeB magnetic material coated with a Ni film by a conventional technique was used.

  A sliding property test was performed on each sample as follows. In the sliding property test, a static friction coefficient was measured by using a 10 mm × 10 mm iron piece as a counterpart material on which a sample was slid, and using an inclined static friction measuring machine as a measuring machine. In this case, the contact weight was 200 g, and the measurement time was about 10 s. The results are shown in Table 1.

  As can be seen from Table 1, the samples 11 and 12 of the present invention have a lower coefficient of static friction and can improve the slipperiness compared with the comparative sample 11 coated with a Ni film by a conventional technique. confirmed. In addition, it was confirmed that the reference sample 11 covered with the DLC film not containing fullerene can improve the slipperiness as compared with the comparative sample 11.

(2) Difference in coating state of fullerene film depending on presence / absence of ultrasonic irradiation A sample in which a fullerene film is formed by the same method as sample 11 except that ultrasonic irradiation is not performed is a fullerene film by the same method as sample 21 and sample 11. Sample 22 was formed as Sample 22. SEM photographs of the surfaces of Samples 21 and 22 are shown in FIGS.

  2 and 3, the white portion indicates fullerene, and the black portion indicates the surface of the magnetic material. As can be seen from FIGS. 2 and 3, the sample 21 (FIG. 2) that was not irradiated with ultrasonic waves has many exposed portions of the magnetic material surface, whereas the sample 22 (FIG. 2) that was irradiated with ultrasonic waves. In 3), it was confirmed that a fullerene film was formed on substantially the entire surface of the magnetic material. Thereby, it was confirmed that it is preferable to irradiate ultrasonic waves when forming the fullerene film.

  DESCRIPTION OF SYMBOLS 1 ... Rotor, 11 ... Rotor core, 12 ... Slot, 21 ... Magnetic body, magnet, 22 ... Protective film, 31 ... Resin film

Claims (7)

Forming a protective film containing at least fullerene of fullerene and DLC on the surface of the magnetic material;
Inserting the magnetic body having the protective film into a slot of a rotor core;
Filling a liquid resin material between the protective film on the surface of the magnetic body and the inner peripheral surface of the slot, and curing the resin material to form a resin film,
The method for manufacturing a rotor, wherein the fullerene is diffused into the resin material when the resin film is formed.   The method for manufacturing a rotor according to claim 1, wherein the resin material is cured by heat treatment.   The method for manufacturing a rotor according to claim 1 or 2, wherein a heating temperature in the heat treatment is set in a range of 60 to 180 ° C. A rotor core having a slot;
A magnet provided in the slot;
A protective film formed on the surface of the magnet and containing at least fullerene of fullerene and DLC;
A resin film formed between the protective film on the surface of the magnetic body and the inner peripheral surface of the slot;
The rotor is characterized in that the fullerene is diffused in the resin film.   A magnet having a protective film containing at least fullerene of fullerene and DLC formed on a surface thereof.   The magnet according to claim 5, wherein the protective film is a fullerene film, and the film thickness is in a range of 0.7 nm to 100 μm.   The magnet according to claim 5, wherein the protective film is a fullerene-containing DLC film, and the film thickness thereof is in a range of 1 nm to 100 μm.

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