JP7466772B2 - ROTOR, ROTATING MACHINE USING THE ROTOR, AND METHOD FOR MANUFACTURING THE ROTOR - Google Patents

Description

The disclosed technology relates to a rotor and a rotating machine using the same.

Technology for integrating metal and resin is in demand in a wide range of fields, including the manufacturing of parts for industrial equipment. There are many possible combinations of metal and resin, but one example would be combining magnesium alloy with CFRP.

For example, Patent Document 1 discloses a technique for bonding CFRP to a magnesium alloy with an epoxy adhesive to create a composite of magnesium alloy and CFRP. More specifically, the technique disclosed in Patent Document 1 includes a chemical conversion treatment process in which a magnesium alloy part is immersed in an aqueous solution containing permanganate to form ultrafine irregularities on the surface.

International Publication No.: WO2008/133096

There is also a demand for the rotors that make up rotating machines to be manufactured by integrating magnesium alloy and CFRP. However, when the technology described in Patent Document 1 is applied to rotors, there is an issue that the strength of the surface layer of the part that has been subjected to the chemical conversion treatment is reduced, making it impossible to use it in high-speed rotating machines.

The present disclosed technology aims to solve the above problems and provide a rotor manufactured by integrating magnesium alloy and CFRP, and a rotating machine equipped with the rotor.

The rotor according to the disclosed technology has the following characteristics: It includes a rotating central portion made of a magnesium alloy, on which an anodized coating is formed and which is subjected to a chemical conversion treatment, and a rotating peripheral portion made of a titanium alloy or CFRP, the rotating central portion and the rotating peripheral portion are of a size that fits together, and the anodized coating has a Vickers hardness of 300 [Hv] or more.

The rotor according to the disclosed technology has an anodized coating with a Vickers hardness of 300 [Hv] or more, so that the coating applied to the magnesium alloy does not crack and the strength of the surface layer does not decrease. The disclosed technology, which uses an anodized coating, realizes a rotor that integrates magnesium alloy and CFRP, and provides a rotating machine equipped with the rotor.

FIG. 1 is a central cross-sectional view of a rotating machine according to a first embodiment of the present invention, as viewed from the right side. 2 is a deformed front view and a rear view of the rotating machine shown in FIG. 1. FIG. FIG. 3 is a second central cross-sectional view of the rotating machine according to the first embodiment as viewed from the right side. 4A and 4B are front and rear views of the rotating machine shown in FIG. 3 in a deformed state. FIG. 5 is a second part of a deformed front view and a rear view of the rotating machine shown in FIG.

Embodiment 1.
Fig. 1 is a central cross-sectional view of a rotating machine 100 according to embodiment 1 as viewed from the right side. As shown in Fig. 1, the rotating machine 100 includes a rotor 10 and a stator 20. The rotating machine 100 is also covered by an external housing 30 (not shown). The rotor 10 includes an iron core 11, a magnet 12, a shaft portion 13, a rotating central portion 14, a rotating peripheral portion 15, and fastening members 16.

The rotating central portion 14 of the rotor 10 is made of a magnesium alloy material. The magnesium alloy material for the rotating central portion 14 may be a cast or extruded material. Specifically, the magnesium alloy material may be any of AZ31, AZ61, AZ91D, ZK10, ZK60, AZX612, WE43, EV31, AE41A, WE54A, AMX602, AZX912, and Mg-Zn-Y alloys. The magnesium alloy material may be O material or H24 material when classified by quality. The magnesium alloy material may be subjected to T5 heat treatment, T6 heat treatment, or other heat treatment or processing to obtain strength characteristics.

When the rotating machine 100 is used in an aircraft, rail car, or other means of transportation, it is important that it does not burn. The magnesium alloy material used in the disclosed technology may have Ca or rare earths added to it to provide flame retardancy. Examples of flame retardant magnesium alloy materials include AZX612, AZX912, WE43, and EV31.

The central rotating portion 14 of the rotor 10 is provided with an anodized coating used for magnesium. The anodized coating of the central rotating portion 14 preferably has a Vickers hardness of 300 [Hv] or more. The anodized coating of the central rotating portion 14 may be a coating produced by a general-purpose HAE method, or a PEO (Plasma Electrolytic Oxidation)-based coating. The method of producing the anodized coating on the central rotating portion 14 may be a method of generating a PEO coating from a solution using sodium silicate, sodium phosphate, ammonium phosphate, sodium aluminate, or ammonium salt, or a coating technology using plasma electrolytic deposition may be used. The central rotating portion 14 may be fluorinated in parallel with the anodization treatment.

The main reason why a coating with a Vickers hardness of 300 [Hv] or more is required is to prevent damage during the assembly process of the rotor 10 and to prevent damage that may occur while the rotating machine 100 is in operation. There is no upper limit for the hardness of the coating in the specifications, but it can be said to be 2000 [Hv] or less due to the limitations of the manufacturing process. In general, even if an anodized coating is a PEO-based coating, which is considered to have relatively few pores, it actually has pores. From the viewpoint of preventing coating cracks that reach the base material even if there is a certain degree of deviation in the coating thickness and hardness, the hardness of the anodized coating of the rotating center part 14 is preferably 1700 [Hv] or less, and more preferably 1400 [Hv] or less.

From the viewpoint of corrosion resistance, the thickness of the anodized coating on the rotating central portion 14 is desirably 5 μm or more, and more desirably 10 μm or more for greater reliability. The upper limit of the coating thickness depends on the alloy material and processing method, but is generally said to be approximately 40 μm. If the coating thickness exceeds the upper limit, the coating will be induced to crack. Therefore, the thickness of the anodized coating on the rotating central portion 14 is desirably 30 μm or less, and more desirably 25 μm or less.

The rotating central part 14 according to the present disclosure is subjected to a chemical conversion treatment after the anodized coating is formed. The chemical conversion treatment is performed to form a chemical conversion film and prevent cracks from reaching the base material of the rotating central part 14 made of a magnesium alloy material.
Although not essential, after the anodized coating is formed and before the chemical conversion treatment is performed, the rotating central portion 14 may be subjected to a heat treatment, for example, a thermal cycle from 180° C. to −65° C. may be performed about 5 to 100 times.

Considering the environment in which the rotating machine 100 is normally used, the biggest cause of corrosion is salt. This is known as salt damage, and the chloride ions in the salt corrode magnesium alloys. Therefore, it is desirable for the chemical treatment applied to the rotating center part 14 to involve a reaction with fluorine ions in order to protect it from corrosion by chloride ions.

The chemical conversion treatment applied to the central rotating part 14 may be one using chromic acid. However, from the viewpoint of environmental regulations, it is desirable that the chemical conversion treatment be chromic acid-free. The chemical conversion treatment applied to the central rotating part 14 may be one using, for example, zirconium utilizing fluoride. As a specific example, the chemical conversion treatment may use a treatment liquid in which ammonium fluorozirconate salt is dissolved and the pH is adjusted to a range of 2.5 to 4.5. The chemical conversion treatment using fluoride forms a fluoride surface layer on the metal. The fluoride surface layer, which is a chemical conversion treatment film, is also called a fluoride coating. The advantage of this method is that it can be easily inspected using fluorescent X-rays after the chemical conversion treatment. In the chemical conversion treatment, instead of zirconium, a coating may be formed with atoms that can be co-deposited with zirconium, such as Mo, V, Ti, etc., or may be co-deposited with a silicon compound. In addition, phosphoric acid or an organic acid may be added to the chemical conversion treatment.

The functions required of the chemical conversion coating are to exhibit corrosion resistance and not to form a weak boundary layer. From the above viewpoints, a practical thickness for the chemical conversion coating is 15 nm or more and less than 1 μm. The thickness of the chemical conversion coating of the rotating center part 14 according to the present disclosure is preferably 30 to 500 nm. Here, the thickness of the coating is ideally measured by cross-sectional observation using a transmission electron microscope. However, the thickness of the coating may be estimated as the SiO2 equivalent thickness when sputtering is performed using spectroscopy such as XPS.

The rotating peripheral portion 15 of the rotor 10 according to the disclosed technology is made of carbon fiber reinforced plastic (hereinafter referred to as "CFRP"). The carbon fibers constituting the CFRP may be PAN-based carbon fibers or pitch-based carbon fibers. The carbon fibers may be in any form, such as unidirectional material, cloth, short fibers, nonwoven fabric, etc. From the viewpoint of versatility and performance stability, the rotating peripheral portion 15 according to the disclosed technology is preferably made of, for example, PAN-based continuous fiber carbon fibers.

Resins used as the matrix for CFRP include thermoplastic resins such as polypropylene and polyamide, and thermosetting resins such as epoxy resin, phenolic resin, and unsaturated polyester resin. Considering adhesion to carbon fiber and mechanical properties, epoxy resin is suitable.

Methods for molding CFRP include press molding, autoclave molding, and sheet winding molding. In all molding methods, the matrix resin composition is subjected to pressure and heated to harden.

Another molding method for CFRP is the range transfer molding technique known as the RTM method. The RTM method involves cutting, laminating, and shaping a carbon fiber substrate such as a carbon fiber fabric to create a preform, placing the preform in a mold and closing the mold, injecting resin to impregnate the preform, allowing it to harden, and then opening the mold to remove the molded product.

The rotating periphery 15 may be made of a titanium alloy instead of CFRP.

The dimensions of the shaft portion 13 and the rotating central portion 14, and the rotating central portion 14 and the rotating peripheral portion 15 are determined so that they fit together (see FIG. 1). The fitting portions may be tapered. As shown in FIG. 1, the rotating central portion 14 and the rotating peripheral portion 15 may be fastened together by fastening members 16. The fastening members 16 may be, for example, bolts and nuts. Although not shown, stainless steel bolts may be used to fasten the iron core 11 and the rotating central portion 14 together.

Figure 2 is a deformed front view and rear view of the rotating machine 100 shown in Figure 1. The right side of Figure 2 is the front view, and the left side of Figure 2 is the rear view. As Figure 2 shows, a structure in which a key fits into a key groove (hereinafter simply referred to as a "key groove structure") is adopted for each of the shaft portion 13 and the rotating central portion 14, and the rotating central portion 14 and the rotating peripheral portion 15. The key may be subjected to R-chamfering to prevent stress concentration at the corners.

After the central rotating portion 14 and the peripheral rotating portion 15 are integrated, they may be painted to improve corrosion resistance. Furthermore, if there is a gap between the central rotating portion 14 and the peripheral rotating portion 15, the gap may be filled with a resin having low viscosity and adhesive properties after they are integrated.

Figure 3 is a second central cross-sectional view of the rotating machine 100 according to embodiment 1 as viewed from the right side. Figure 4 is a deformed front view and rear view of the rotating machine 100 shown in Figure 3. The right side of Figure 4 is a front view, and the left side of Figure 4 is a rear view. The rotating machine 100 shown in Figures 3 and 4 has a rotating central portion with a shaft 14B made of a magnesium alloy material instead of the shaft portion 13 and the rotating central portion 14. The rotor 10 according to the disclosed technology may be configured to have a rotating central portion with a shaft 14B.

Figure 5 shows a deformed front view and a second rear view of the rotating machine 100 shown in Figure 1. The right side of Figure 5 is the front view, and the left side of Figure 5 is the rear view. As shown in Figure 5, the shape of the key and key groove used in the disclosed technology may have a curved surface. The shape, size and number of the key groove structure may be determined by appropriate design.

To summarize the rotor 10 according to the disclosed technology from the viewpoint of a production method, the process includes the steps of forming an anodized coating having a Vickers hardness of 300 Hv or more on the rotating central portion 14 made of a magnesium alloy, performing a chemical conversion treatment on the rotating central portion 14 on which the anodized coating has been formed, and fitting the rotating central portion 14 to the rotating peripheral portion 15.

As described above, the rotor 10 according to the first embodiment has an anodized coating with a Vickers hardness of 300 [Hv] or more, so that the coating applied to the magnesium alloy does not crack or lose its surface strength. As a result, the rotor 10 according to the disclosed technology can achieve a weight reduction of 20% or more compared to a conventional rotor made of a titanium alloy.

The rotor of the disclosed technology can be applied to rotating machines and has industrial applicability.

10 rotor, 11 iron core, 12 magnet, 13 shaft portion, 14 rotating central portion, 15 rotating peripheral portion, 16 fastening member, 20 stator, 30 outer casing, 40 bearing, 100 rotating machine.

Claims (4)

a rotating central portion made of a magnesium alloy, on which an anodized film is formed and on which a chemical conversion treatment is performed;
A rotating peripheral portion made of a titanium alloy or CFRP,
the central rotating portion and the peripheral rotating portion are sized to fit together,
The anodized coating has a Vickers hardness of 300 [Hv] or more. A rotor as described in claim 1, wherein the chemical conversion treatment forms a fluoride surface layer on the magnesium alloy. forming an anodic oxide coating having a Vickers hardness of 300 [Hv] or more on a rotating central portion made of a magnesium alloy;
a step of subjecting the rotating central portion on which the anodic oxide coating is formed to a chemical conversion treatment;
and mating said rotating central portion with said rotating peripheral portion. A rotating machine comprising a rotor according to claim 1 or 2, or a rotor produced by the method according to claim 3.

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