JPH0965622A - Parts for high-efficiency rotor and rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the efficiency deterioration of a motor and to obtain a practical corrosion resistance by constituting parts for rotor of specific elements and specifying the plated thickness of the parts. SOLUTION: Cylindrical or fan-shaped parts 4 for rotor are constituted of a permanent magnet composed of 5-40wt.% R (one or more kinds of elements selected from among rare-earth elements containing Y), 50-90wt.% TM (one or more kinds of elements selected from among Fe, Co, Ni, Ga, Al, Ti, V, Cr, Mn, Zr, Hf, Nb, Ta, Mo, Ge, Sb, Sn, and Bi), and 0.2-8wt.% B. The inside diameter or inside radius side of the parts 4 is integrally stuck to a rotor yoke 3 with an adhesive having an air shielding property and water repellency. The thickness of an oxidation-resistant metallic film plated to the surface of the parts 4 at the central part in the external-size or outside-radius section is adjusted to 10-50μm and the thickness of the film at the inside-diameter or inside-radius section is adjusted to <=10μm. Therefore, the efficiency deterioration of a motor can be improved and a practical corrosion resistance can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical or fan-shaped rotor component composed of an R-TM-B type permanent magnet body, and controlling the thickness of a metal plating film formed on the surface thereof. Thus, the present invention relates to a rotor component which has a practical corrosion resistance and has a markedly improved reduction in motor efficiency due to a metal plating film.

[0002]

2. Description of the Related Art As electric and electronic devices have become higher in performance and smaller in size, the same demands have been made for permanent magnets used as a part of these devices. As a high-performance permanent magnet capable of meeting these requirements, an R-TM-B based permanent magnet (here, R is one or a combination of two or more rare earth elements including Y, and TM is Fe, Co, Ni, Ga, Al, T
i, V, Cr, Mn, Zr, Hf, Nb, Ta, Mo,
One or a combination of two or more of Ge, Sb, Sn and Bi. B is boron. ) Has been developed and is steadily increasing its production. However, since the R-TM-B permanent magnet contains a large amount of iron and neodymium as main components, there is a problem that it is extremely rusty. Therefore, in order to improve the corrosion resistance, a measure has been taken to provide an oxidation resistant coating on the surface of the R-TM-B based permanent magnet body. As the type of the coating layer, metal plating, resin, metal vapor deposition, etc. have been proposed and put into practical use. Among them, the metal plating film has an advantage that the surface coating layer has excellent mechanical strength as compared with the oxidation resistant resin, and that the coating layer itself has almost no hygroscopicity.

[0003]

[Problems to be Solved by the Invention] Metal-plated RT
The corrosion resistance of the MB magnet depends on the film thickness of the metal plating. FIG. 1 shows the relationship between the rust occurrence rate of the R-TM-B system magnet in the salt spray test and the film thickness of the Ni plating plated on the R-TM-B system magnet. The test conditions are 5% NaCl.
1, 35 ° C., 100 h. It can be seen that rust is generated in the magnet having a plating film thickness of less than 10 μm, and a plating film thickness of 10 μm or more is necessary to secure practical corrosion resistance. On the other hand, application of the high-performance R-TM-B system permanent magnet body to a rotating machine such as a motor enables high efficiency and downsizing, and thus its application is expanding. FIG. 2 shows a configuration example of the inner rotor type motor. In the motor of this type, the rotor component (4) composed of a permanent magnet body is used together with the rotor yoke (3) so that the rotor component and the rotor yoke are bonded and integrated. At this time, in order to increase the rotation efficiency of the motor as much as possible, the clearance (5) between the rotor component and the rotor yoke must be integrated so as to be as small as possible. Therefore, the clearance between the inner diameter of the rotor component and the outer diameter of the rotor yoke must be designed to be as small as possible. However, in the R-TM-B type permanent magnet body, an oxidation resistant coating must be formed on the surface of the magnet in order to obtain practical corrosion resistance, and this coating has the same motor efficiency as the clearance (5). There is a problem that it causes a decrease. FIG. 3 shows the relationship between the Ni plating film thickness at the center of the inner diameter of the permanent magnet body and the rate of decrease in motor efficiency. The gap (2) between the inner diameter of the stator yoke (1) and the outer diameter of the rotor component (4) was 0.3 mm, and the clearance between the outer diameter of the rotor yoke (3) and the inner diameter of the rotor component (4) was 20 μm. is there. It can be seen that the motor efficiency decreases as the film thickness of the plating increases, but especially when the Ni plating film thickness is 10 μm or more. From the above, it is difficult to provide a rotor component made of an R-TM-B type magnet of the inner diameter bonding type that secures practical corrosion resistance and has a small decrease in magnetic characteristics in the related art. I had to sacrifice one. An object of the present invention is to provide a cylindrical or fan-shaped rotor component that improves the reduction in motor efficiency due to the oxidation-resistant metal plating film of the rotor component made of the R-TM-B system magnet and ensures practical corrosion resistance. Is to provide.

[0004]

The inventors of the present invention have made earnest studies to solve the above-mentioned problems, and as a result, in order to obtain practically sufficient corrosion resistance without deteriorating magnetic characteristics, R-TM-B type magnets have been obtained. It has been found that the thickness of the oxidation-resistant metal plating film on the outer diameter or outer R side and the inner diameter or inner R side of the rotor component can be set within a certain range. Therefore, in the present invention, R (where R is a combination of one or more rare earth elements including Y) is 5 to 40% by weight, TM (here, TM is Fe, Co, Ni, Ga, Al, or Ti, V, C
r, Mn, Zr, Hf, Nb, Ta, Mo, Ge, S
One or a combination of two or more of b, Sn and Bi. )
The inner diameter or the inner R side of a cylindrical or fan-shaped rotor component composed of a permanent magnet body composed of 50 to 90% and B (boron) 0.2 to 8% is bonded via an adhesive having air blocking property and water rupture property. In a cylindrical or fan-shaped rotor component integrally bonded to a rotor yoke, the outer diameter of the oxidation-resistant metal plating film formed on the surface of the rotor component or the film thickness of the outer R central portion is 10 μm or more and 50 μm or less. And, the technical means that the film thickness of the inner diameter or the central portion of the inner radius is less than 10 μm was adopted.

[0005]

The outer diameter or the outer R side of the rotor component made of the cylindrical or fan-shaped R-TM-B system magnet is exposed to the atmosphere. To secure practical corrosion resistance of this part,
It suffices to form an oxidation resistant metal plating film of m or more and 50 μm or less. If the film thickness is less than 10 μm, sufficient corrosion resistance cannot be obtained. Further, when the film thickness exceeds 50 μm, the dimensional accuracy is deteriorated, and in particular, the plating is excessively thick on the end portion on the outer shape side, which makes it difficult to secure a space between the stator yoke and the rotor component including the R-TM-B magnet. , The rotor may not rotate, which is not practical. On the other hand, the corrosion resistance on the inner diameter side or the inner R side of the rotor component is the same as the rotor component.
When it is adhered to the magnet, it is protected by the adhesive and the rotor yoke adhered by adhering it with an adhesive having an air blocking property and a water rupture property, so that practical corrosion resistance is secured even when the oxidation resistant film is thin, Moreover, the rotation efficiency of the motor is not impaired. If a ferromagnetic film such as a Co-Ni film or a Co-Ni-P film is formed by plating as the metal plating film, the deterioration of magnetic characteristics can be further reduced.

[0006]

EXAMPLES The effects of the present invention will be specifically described with reference to examples. An alloy having a composition of Nd (Fe _0.7 Co _0.2 B _0.07 Ga _0.03 ) _{6.5 was} prepared by arc melting, and the obtained ingot was roughly crushed by a stamp mill and a disc mill. Then, fine pulverization was carried out by a jet mill using N ₂ gas as a pulverizing medium to obtain fine pulverized powder having a pulverized particle size of 3.5 μm. The obtained raw material powder was subjected to transverse magnetic field molding in a magnetic field of 15 kOe. The molding pressure was ² ton / cm ² . Then, the molded body was sintered in vacuum at 1100 ° C. for 2 hours. Further, it was heated and held in an argon atmosphere at 900 ° C. for 2 hours and then rapidly cooled, and then held in an argon atmosphere whose temperature was kept at 600 ° C. for 1 hour. Then, the sintered body was processed into a cylindrical shape of 30φ × 25φ × 30t. With respect to the sample thus obtained, a nickel layer by electroplating was formed in a Watt bath as an oxidation resistant metal plating film. During plating, the thickness of the nickel coating on the inner diameter side is adjusted using a shielding plate or an auxiliary cathode,
Samples having different thicknesses of the metal plating films on the outer diameter side and the inner diameter side center were prepared. Further, the plating film thickness of the prepared sample was measured by embedding and polishing the sample and then taking a photograph of the cross section.
After the inner diameter of the obtained sample and the outer diameter of the rotor yoke were bonded with an epoxy resin, the corrosion resistance was evaluated. To evaluate the corrosion resistance, a salt spray test (5% NaCl, 35 ° C., 100 h) and a constant temperature and humidity test (80 ° C., 90% RH, 500 h) were performed with the rotor yoke bonded to the inner diameter side of the sample. In addition,
Confirm the presence or absence of rust on the inner diameter side after the corrosion resistance test at 500 ° C
It was confirmed by conducting a ferroxyl test after heating the above to evaporate the epoxy resin and remove the rotor yoke. Table 1
Shows the evaluation results of corrosion resistance. By bonding the rotor component made of the R-TM-B type magnet and the outer diameter of the rotor yoke with an epoxy type adhesive having air blocking property and water rupture property,
It can be seen that even if the plating thickness on the inner diameter side of the rotor component is less than 10 μm in which the magnetic characteristic deterioration is small, corrosion resistance with no practical problems can be obtained. In Comparative Example 1, since the plating thickness on the outer diameter side was less than 10 μm, rusting occurred on the outer diameter side. In Comparative Example 2, since the rotor yoke was not bonded to the inner diameter side, rusting occurred on the inner diameter side. In Comparative Example 3, the plating thickness is 10 for both the inner and outer diameters.
Since the thickness is at least μm, corrosion resistance is secured, but as shown in FIG. 3, the inner diameter side plating film thickness is large, and the magnetic properties are significantly deteriorated.

[0007]

[Table 1] In addition, although the present example shows an example in which the oxidation-resistant coating is nickel-plated, even when another oxidation-resistant metal plating coating is used, the plating thickness of the inner and outer diameters can be set within the thickness range of the present invention. The same effect can be obtained. Further, although the example of the cylindrical rotor component is shown in the present embodiment, the same effect can be obtained also in the case of the fan-shaped rotor component. Further, in this embodiment, the epoxy adhesive is used as the adhesive having the air barrier property and the water rupture property, but the same effect can be obtained by using another adhesive having the air barrier property and the water rupture property.

[0008]

EFFECTS OF THE INVENTION Since the present invention has the above-mentioned structure and action, practical corrosion resistance is ensured by setting the thickness of the inner and outer diameters of the oxidation resistant metal plating film within a predetermined range. Further, the present invention provides a cylindrical or fan-shaped rotor component in which the magnetic properties are less deteriorated by the metal plating film.

[Brief description of drawings]

FIG. 1 shows the relationship between the film thickness of a Ni plating film and the corrosion resistance according to the present invention.

FIG. 2 shows a configuration example of an inner rotor type motor according to the present invention.

FIG. 3 shows the relationship between the film thickness of the Ni plating film on the inner diameter side of the rotor component and the motor efficiency according to the present invention.

[Explanation of symbols]

1 stator yoke, 2 air gap between outer diameters, 3 rotor yoke, 4 rotor parts, 5 clearance

Claims (3)

[Claims] 1. A weight ratio of R (where R is one or a combination of two or more rare earth elements including Y) 5 to 40%, TM
(Where TM is Fe, Co, Ni, Ga, Al, Ti,
V, Cr, Mn, Zr, Hf, Nb, Ta, Mo, G
One or a combination of two or more of e, Sb, Sn and Bi. ) An adhesive having an air-blocking property and a water-breaking property on the inner diameter or the inner R side of a cylindrical or fan-shaped rotor component composed of a permanent magnet body composed of 50 to 90% and B (boron) 0.2 to 8%. In the cylindrical or fan-shaped rotor component integrally bonded to the rotor yoke via the outer diameter of the oxidation-resistant metal plating film formed on the surface of the rotor component or the outer R central portion thereof has a thickness of 10 μm or more and 50 μm or less. A cylindrical or fan-shaped high-efficiency rotor component characterized in that the film thickness of the inner diameter or the center portion of the inner radius is less than 10 μm. 2. A cylindrical or fan-shaped rotor component, wherein the oxidation-resistant metal plating film according to claim 1 is a ferromagnetic metal plating. 3. A rotor using the high efficiency rotor component according to claim 1.