Rotor, rotary electric machine, and manufacturing method of rotor

Abstract

To provide a technique by which a rotor is effectively cooled without liquid spill in a rotary electric machine.SOLUTION: A rotor 2 comprises: a rotor core 20 (rotor body) laminated with multiple electromagnetic steel sheets; a permanent magnet 95 (magnet) or a coil arranged in the rotor core 20; and a shaft 3 arranged in the rotational axis of the rotor core 20. The shaft 3 of the rotor 2 comprises: an in-shaft cooling air passage 60 (cavity) formed as an open hole penetrating through the shaft in the axial direction; and a heat transfer structure 80 that can ventilate air 99 for cooling, which is arranged in at least part of the in-shaft cooling air passage 60.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a rotor, a rotating electric machine, and a method for manufacturing a rotor. [Background technology]

[0002] Conventionally, techniques for cooling rotors with a cooling fluid in rotating electrical machines such as motors have been known. For example, a technique has been proposed in which gaps are formed between adjacent magnetic steel sheets in the direction of lamination as a rotor core, allowing the cooling fluid to flow from a cooling fluid passage toward the magnets inserted in the magnet insertion holes (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-148746 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, demand for rotating electrical machines such as motors has been growing, and there has also been a strong market demand for high-power motors. High-power motors tend to generate a lot of heat, so there has also been a demand for effective cooling technology. In structures with permanent magnets in the rotor, rotor cooling can prevent performance degradation due to temperature rise of the magnets. To achieve this, it is necessary to efficiently transfer the heat generated by the magnets to the shaft. Conventionally, cooling structures that use a liquid as a coolant in the rotor shaft have been known, but this has been difficult to achieve at high speeds due to issues with liquid leakage.

[0005] The present invention has been made in view of the above circumstances, and has as its object to provide a technique for effectively cooling a rotor without liquid leakage. [Means for solving the problem]

[0006] According to the present invention, the following techniques are provided. (1) A rotor having a rotor body formed by laminating a plurality of electromagnetic steel plates, a magnet or a coil provided on the rotor body, and a shaft provided on a rotation axis of the rotor body, The shaft a cavity formed therein by a through hole passing through in the axial direction; a heat transfer structure provided in at least a part of the cavity and capable of ventilating cooling air; A rotor having (2) The rotor according to (1), wherein the heat transfer structure has a fin structure. (3) The rotor according to (2), wherein the fin structure has corrugated fins formed by bending a metal plate into a wave shape. (4) The rotor according to (2) or (3), wherein the fin structure has plate fins in which metal plates are arranged in a row. (5) The rotor according to any one of (2) to (4), wherein the fin structure has honeycomb fins in which a plurality of cylindrical portions separated by partition walls are arranged. (6) The rotor according to any one of (2) to (5), wherein the fin structure has a multi-layer structure formed in multiple layers in the radial direction. (7) The rotor according to (6), wherein the multi-layer structure has a cylindrical sleeve that separates the layers. (8) The rotor according to any one of (1) to (7), wherein the heat transfer structure has a porous structure. (9) The rotor according to any one of (1) to (8), wherein a plurality of the heat transfer structures are arranged side by side in the axial direction. (10) The rotor according to any one of (1) to (9), wherein at least a portion of the heat transfer structure is biased toward an inner wall of the cavity. (11) The rotor according to any one of (1) to (10), wherein at least one end of the through hole is tapered or rounded. (12) The rotor body is The magnet; a magnet arrangement section that accommodates the magnet; a magnet sealing resin portion made of a cured resin composition filled in a space formed between the magnet and a wall surface of the magnet placement portion when the magnet is placed in the magnet placement portion; and and The thermal conductivity of the cured product of the magnet sealing resin portion is 0.3 W / m K or more. A rotor according to any one of (1) to (11). (13) The rotor body is a shaft placement through-hole that penetrates the rotor body to the axial center and into which the shaft is placed; a shaft sealing resin portion made of a cured product of a resin composition filled in a space between the shaft and a wall surface of the shaft placement through hole when the shaft is placed in the shaft placement through hole; and the thermal conductivity of the cured product of the shaft sealing resin portion is 0.3 W / m K or more; A rotor according to any one of (1) to (12). (14) A rotating electric machine having a rotor according to any one of (1) to (13) and a stator, A rotating electric machine having an air inlet portion that surrounds one end of a through hole provided in a shaft of the rotor and through which cooling air passes when the air is introduced into the through hole. (15) The rotating electric machine according to (14), further comprising an air discharge portion that is provided so as to surround the other end of the through hole and through which the air passes when the air is discharged from the through hole. (16) A method for manufacturing a rotor having a rotor body formed by laminating a plurality of electromagnetic steel plates, a magnet or a coil provided on the rotor body, and a shaft provided on a rotation axis of the rotor body, the method comprising: a shaft preparation step of preparing a hollow shaft having a through hole passing through in the axial direction; a heat transfer structure preparation step of preparing a heat transfer structure that is breathable; a heat transfer structure inserting step of inserting at least one of the heat transfer structures into the cavity; A method for manufacturing a rotor having the above structure. (17) The method for manufacturing a rotor according to (16), wherein at least one end of the through hole is tapered or rounded. (18) In the heat transfer structure, a width in a direction perpendicular to a direction of insertion into the cavity is larger than an outer diameter of the cavity, The heat transfer structure inserting step includes compressing at least a portion of the heat transfer structure against an inner wall of the cavity. A method for manufacturing a rotor according to (16) or (17). [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a technique for effectively cooling a rotor without causing liquid leakage. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of a motor according to an embodiment, taken perpendicular to a rotation shaft thereof. [Figure 2] 1 is a cross-sectional view taken along a rotation shaft of a motor according to an embodiment. [Figure 3] 1 is a cross-sectional view taken perpendicular to the rotation axis of a rotor according to an embodiment of the present invention. [Figure 4] FIG. 2 is a cross-sectional view taken along the rotation axis of the shaft according to the embodiment. [Figure 5] FIG. 2 is a cross-sectional view taken perpendicular to the rotation axis of the shaft according to the embodiment. [Figure 6] FIG. 2 is a cross-sectional view of a heat transfer structure according to an embodiment. [Figure 7] FIG. 2 is an exploded cross-sectional view of the heat transfer structure according to the embodiment. [Figure 8] 5A and 5B are diagrams illustrating the shape of an end portion of a cooling air flow path in a shaft according to the embodiment. [Figure 9] FIG. 10 is a cross-sectional view taken along the rotation axis of a shaft according to a modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, like components are designated by like reference numerals, and the description thereof will be omitted as appropriate.

[0010] <Motor 1> Fig. 1 is a cross-sectional view taken perpendicular to the shaft 3 (rotation axis L) of the motor 100. Fig. 2 is a cross-sectional view taken along the shaft 3 (rotation axis L) of the motor 100. 3 is a cross-sectional view taken along a line perpendicular to the rotation axis L of the rotor 2. FIG. 4 is a cross-sectional view taken along the rotation axis L of the shaft 3.

[0011] In this embodiment, the rotating electric machine is exemplified by a motor 100. The motor 100 is used, for example, as a drive motor for an automobile.

[0012] The motor 100 has, as its cooling structure, an air-cooled rotor cooling structure that cools the rotor 2 and a water-cooled stator cooling structure that cools the stator 4. The following mainly describes the rotor cooling structure. In the rotor cooling structure, a through-hole that penetrates the shaft 3 at the center of the shaft is provided as an intra-shaft cooling air flow path 60. The intra-shaft cooling air flow path 60 is cooled by flowing air 99 through the intra-shaft cooling air flow path 60. Furthermore, to improve cooling performance, a heat transfer structure 80 is provided inside the intra-shaft cooling air flow path 60. In this way, by adopting an air-cooled rotor cooling structure, a sealing structure for the shaft 3 is not required. In other words, the rotor 2 can be effectively cooled without liquid leakage.

[0013] Furthermore, the rotor 2 will be described as having permanent magnets 95 arranged in a V-shape and embedded in the rotor core 20 (also referred to as the "rotor body"); however, the arrangement of the permanent magnets 95 may be other than a V-shape. The number of permanent magnets 95 can be determined depending on the specifications of the rotor 2 of the motor 100, and may be other than the number illustrated below. Furthermore, instead of the permanent magnets 95, any magnet may be embedded in the rotor core 20, and a field winding type magnet may be used. The specific details will be explained below.

[0014] The motor 100 comprises a housing 1 , a shaft 3 , a rotor 2 , a stator 4 and an air intake enclosure 40 . The housing 1 has a cylindrical housing portion 1a that houses the stator 4 along its outer circumferential surface, and housing end portions 1b that close both axial ends of the cylindrical housing portion 1a. The housing 1 can be made of a material such as an aluminum alloy (cast metal product), a resin material, or a combination thereof.

[0015] The shaft 3 is rotatably supported by the housing end 1b via bearings 3a and 3b. The shaft 3 has an in-shaft cooling air flow path 60. The in-shaft cooling air flow path 60 is a through-hole that passes through the shaft 3 from one end 3e to the other end 3f at the center of the rotation axis.

[0016] The stator 4 has a stator core fixed to the housing 1 (the housing cylindrical portion 1a) and a coil 9 assembled to the stator core. More specifically, the stator 4 has an annular yoke portion 6 and a plurality of teeth portions 7 that are integral with the yoke portion 6 and extend toward the rotor 2.

[0017] The spaces between adjacent teeth 7 form slots 8, and coils 9 are housed in the slots 8 and sealed with resin. Additionally, cooling channels 10 extending in the axial direction are provided in the slots 8 as part of the stator cooling structure. A liquid (e.g., water) is introduced into the cooling channels 10 as a coolant. The cooling channels 10 are connected to the outside via through holes 1f and 1g provided in the housing end 1b.

[0018] <Rotor> The rotor 2 has a rotor core 20 that rotates around a rotation axis L (i.e., shaft 3), a plurality of permanent magnets 95 provided in the rotor core 20 and extending in the direction of the rotation axis, and a plurality of magnet arrangement portions 29 provided in the rotor core 20 that each house one of the plurality of permanent magnets 95.

[0019] Furthermore, the rotor 2 has side plates 5 (also called end plates) provided at the ends of the rotor core 20 in the direction of the rotation axis L.

[0020] <Rotor core> Rotor core 20 has a generally cylindrical shape formed by laminating a plurality of magnetic steel sheets formed into annular disk shapes. The magnetic steel sheets may be laminated and joined by caulking or by using an adhesive.

[0021] Each of the electromagnetic steel plates that make up the rotor core 20 has a central opening at the center and multiple rectangular openings near the outer edge. When the electromagnetic steel plates are stacked, the central opening becomes a through hole aligned in the direction of the rotation axis L, forming the shaft arrangement hole 25, and the openings become the magnet arrangement sections 29. The shaft 3 is attached to the shaft arrangement hole 25. The magnet arrangement sections 29 house permanent magnets 95. The outer diameter of the rotor core 20 is, for example, not less than 50 mm and not more than 500 mm.

[0022] <Permanent magnet> The permanent magnet 95 is a rectangular parallelepiped and is housed in the magnet arrangement section 29. The permanent magnet 95 is embedded in the rotor core 20 and extends in the axial direction, forming the magnetic poles of the rotor 2. A plurality of permanent magnets 95 are provided, and the rotor 2 includes a plurality of magnet sets, each consisting of a pair of permanent magnets 95. In this embodiment, the rotor 2 is an eight-pole rotor. The pair of permanent magnets 95 are arranged in a V-shape, with the longitudinal directions of their rectangular shapes opening outward in the radial direction. A pair of permanent magnets 95 arranged in a V-shape constitutes one magnetic pole.

[0023] The permanent magnet 95 can be a ferrite magnet, an alnico magnet, a rare earth magnet, or the like. As a rare earth magnet, a neodymium magnet, whose main components are neodymium (Nd), iron (Fe), and boron (B), can be suitably used. Because neodymium magnets have a high magnetic flux density and very strong magnetic force, they are suitable for motors 100 that require high output, such as those used in electric vehicles. Alternatively, a samarium-cobalt magnet (SmCo magnet) can be used as the permanent magnet 95 from the standpoint of corrosion resistance and heat resistance.

[0024] <Magnet sealing resin part> The magnet sealing resin portion 96 is made of a cured resin composition that is filled into the space formed between the permanent magnet 95 and the wall surface of the magnet arrangement portion 29 when the permanent magnet 95 is accommodated in the magnet arrangement portion 29. The magnet sealing resin portion 96 covers the circumferential surface of the permanent magnet 95 accommodated in the magnet arrangement portion 29, and firmly bonds the permanent magnet 95 to the magnet arrangement portion 29.

[0025] The motor 100 is exposed to a severe temperature environment due to its use environment or its own operation. Therefore, the resin material for the magnet sealing resin portion 96 can be, for example, one or two types of thermosetting resin selected from the group consisting of epoxy resin and phenol resin.

[0026] The hardened resin material that constitutes the magnet sealing resin portion 96 has the following physical properties, for example. The thermal conductivity of the cured resin material is 0.3 W / m K or more. The lower limit of the thermal conductivity is preferably 1.0 W / m K or more, and more preferably 2.0 W / m K or more. The upper limit of the thermal conductivity is not particularly limited, but a practical value is, for example, 10 W / m K.

[0027] The glass transition temperature Tg of the resin composition of the magnet sealing resin portion 96 is 120° C. or higher, preferably 140° C. or higher, and more preferably 160° C. or higher. By setting the glass transition temperature Tg within the above range, the motor 100 can be used at high temperatures, and the permanent magnet 95 becomes more resistant to heat generation, allowing it to be used at high output.

[0028] <Magnet sealing resin material> The resin composition of the magnet sealing resin portion 96 will be specifically described below. The resin composition of the resin layer 50 preferably contains a thermosetting resin (A), a filler (B), a curing agent (C), and the like.

[0029] [Thermosetting resin (A)] Examples of the thermosetting resin (A) include epoxy resins, cyanate resins, polyimide resins, benzoxazine resins, unsaturated polyester resins, phenolic resins, melamine resins, silicone resins, bismaleimide resins, phenoxy resins, and acrylic resins. As the thermosetting resin (A), one of these may be used alone, or two or more may be used in combination. Among these, epoxy resins, phenolic resins, and phenoxy resins are preferred as the thermosetting resin (A) from the viewpoint of high insulating properties, and epoxy resins are particularly preferred from the viewpoint of ensuring flow in extremely narrow sections during molding.

[0030] Examples of epoxy resins include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, bisphenol M type epoxy resin (4,4'-(1,3-phenylenediisopridiene)bisphenol type epoxy resin), bisphenol P type epoxy resin (4,4'-(1,4-phenylenediisopridiene)bisphenol type epoxy resin), and bisphenol Z type epoxy resin (4,4'-cyclohexidienebisphenol type epoxy resin); phenol novolac type epoxy resin, cresol novolac type epoxy resin, trisphenol methane type novolac type epoxy resin, tetraphenol group ethoxylated epoxy resin, and the like. Examples of epoxy resins include novolac-type epoxy resins such as benzophenone-type novolac-type epoxy resins and novolac-type epoxy resins having a condensed ring aromatic hydrocarbon structure; biphenyl-type epoxy resins; aryl alkylene-type epoxy resins such as xylylene-type epoxy resins and biphenyl aralkyl-type epoxy resins; naphthalene-type epoxy resins such as naphthylene ether-type epoxy resins, naphthol-type epoxy resins, naphthalene diol-type epoxy resins, bifunctional to tetrafunctional epoxy-type naphthalene resins, binaphthyl-type epoxy resins, and naphthalene aralkyl-type epoxy resins; anthracene-type epoxy resins; phenoxy-type epoxy resins; dicyclopentadiene-type epoxy resins; norbornene-type epoxy resins; adamantane-type epoxy resins; and fluorene-type epoxy resins. These may be used alone or in combination of two or more.

[0031] Among the epoxy resins, from the viewpoint of further improving heat resistance and insulation reliability, it is preferable to use one or more types selected from the group consisting of bisphenol-type epoxy resins, novolac-type epoxy resins, biphenyl-type epoxy resins, aryl alkylene-type epoxy resins, naphthalene-type epoxy resins, anthracene-type epoxy resins, and dicyclopentadiene-type epoxy resins.

[0032] Examples of phenolic resins include novolac-type phenolic resins such as phenol novolac resin, cresol novolac resin, and bisphenol A novolac resin, and resol-type phenolic resins, etc. One of these may be used alone, or two or more may be used in combination. Among the phenolic resins, phenolic novolac resins are preferred.

[0033] The content of the thermosetting resin (A) is preferably 1% by mass or more, and more preferably 5% by mass or more, based on the total amount of the resin composition of the resin layer 50. On the other hand, the content is preferably 30% by mass or less, and more preferably 20% by mass or less, based on the total amount of the resin composition of the resin layer 50.

[0034] When the content of the thermosetting resin (A) is equal to or greater than the above lower limit, the handleability of the entire resin composition of the resin layer 50 improves, making it easier to form the inner surface resin layer 51 and improving the strength of the inner surface resin layer 51.

[0035] When the content of the thermosetting resin (A) is equal to or less than the upper limit, the linear expansion coefficient and elastic modulus of the inner surface resin layer 51 are further improved, and the thermal conductivity is further improved.

[0036] [Filler (B)] The filler (B) in this embodiment is used from the viewpoint of improving the thermal conductivity of the resin layer 50 (more specifically, the inner surface resin layer 51) and obtaining strength.

[0037] As the filler (B), an inorganic filler is preferred, and a thermally conductive filler is particularly preferred. More specifically, from the viewpoint of achieving a balance between thermal conductivity and electrical insulation, examples of the filler (B) include silica, alumina, boron nitride, aluminum nitride, and silicon carbide. These may be used alone or in combination of two or more. Of these, alumina and boron nitride are preferred as the filler (B).

[0038] The content of the filler (B), ie, the content of the above filler, is preferably 60% by mass or more based on the total amount of the resin composition.

[0039] [Hardening agent (C)] When an epoxy resin or a phenolic resin is used as the thermosetting resin (A), the resin composition preferably further contains a curing agent (C). As the curing agent (C), one or more selected from the curing catalyst (C-1) and the phenol-based curing agent (C-2) can be used.

[0040] Examples of the curing catalyst (C-1) include organic metal salts such as zinc naphthenate, cobalt naphthenate, tin octoate, cobalt octoate, bisacetylacetonate cobalt(II), and trisacetylacetonate cobalt(III); tertiary amines such as triethylamine, tributylamine, and 1,4-diazabicyclo[2.2.2]octane; 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 2,4-diethylimidazole, and 2-phenyl-4-methyl-5-hydroxyimidazole; Examples of suitable curing catalysts include imidazoles such as 2-phenyl-4,5-dihydroxymethylimidazole; organic phosphorus compounds such as triphenylphosphine, tri-p-tolylphosphine, tetraphenylphosphonium tetraphenylborate, triphenylphosphine triphenylborane, and 1,2-bis-(diphenylphosphino)ethane; phenolic compounds such as phenol, bisphenol A, and nonylphenol; and organic acids such as acetic acid, benzoic acid, salicylic acid, and p-toluenesulfonic acid, or mixtures thereof. The curing catalyst (C-1) can be used alone or in combination with two or more of these, including their derivatives.

[0041] The content of the curing catalyst (C-1) is not particularly limited, but is preferably 0.001% by mass or more and 1% by mass or less based on the total amount of the resin composition.

[0042] Examples of the phenolic curing agent (C-2) include novolac-type phenolic resins such as phenol novolac resin, cresol novolac resin, trisphenolmethane-type novolac resin, naphthol novolac resin, and aminotriazine novolac resin; modified phenolic resins such as terpene-modified phenolic resin and dicyclopentadiene-modified phenolic resin; aralkyl-type resins such as phenol aralkyl resins having a phenylene skeleton and / or biphenylene skeleton and naphthol aralkyl resins having a phenylene skeleton and / or biphenylene skeleton; bisphenol compounds such as bisphenol A and bisphenol F; and resol-type phenolic resins, and these may be used alone or in combination of two or more.

[0043] Among these, from the viewpoint of improving the glass transition temperature and reducing the linear expansion coefficient, the phenolic curing agent (C-2) is preferably a novolac type phenolic resin or a resol type phenolic resin. The content of the phenolic curing agent (C-2) is not particularly limited, but is preferably 1% by mass or more, more preferably 5% by mass or more, based on the total amount of the resin composition, and is preferably 30% by mass or less, more preferably 15% by mass or less, based on the total amount of the resin composition.

[0044] [Coupling agent (D)] The resin composition may contain a coupling agent (D), which can improve the wettability at the interface between the thermosetting resin (A) and the filler (B).

[0045] The coupling agent (D) is not particularly limited, but it is preferable to use one or more coupling agents selected from, for example, epoxy silane coupling agents, cationic silane coupling agents, amino silane coupling agents, titanate-based coupling agents, and silicone oil-type coupling agents.

[0046] The content of the coupling agent (D) is not particularly limited, but is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, relative to 100% by mass of the filler (B), and is preferably 3% by mass or less, more preferably 2% by mass or less, relative to 100% by mass of the filler (B).

[0047] [Phenoxy resin (E)] Furthermore, the resin composition may contain a phenoxy resin (E). By containing the phenoxy resin (E), the flex resistance of the resin layer 50 can be improved, and the elastic modulus can be reduced, thereby improving the stress relaxation force of the resin layer 50.

[0048] Furthermore, when the resin layer 50 contains the phenoxy resin (E), the viscosity increases, reducing the flowability and preventing the occurrence of voids, etc. Furthermore, when the resin layer 50 is used in close contact with a metal member (i.e., the teeth 7 or the yoke 6), the adhesion between the metal and the cured resin composition can be improved.

[0049] The phenoxy resin (E) may be, for example, a phenoxy resin having a bisphenol skeleton. Examples of suitable phenoxy resins include phenoxy resins having a naphthalene skeleton, phenoxy resins having an anthracene skeleton, and phenoxy resins having a biphenyl skeleton. Phenoxy resins having a structure containing a plurality of these skeletons can also be used. The content of the phenoxy resin (E) is preferably, for example, 3% by mass or more and 10% by mass or less relative to the total amount of the resin composition.

[0050] [Wax (mold release agent)] The resin composition contains a wax, which can improve the releasability of the resin composition from the mold core after molding. Examples of waxes include natural waxes such as carnauba wax, synthetic waxes such as Montan acid ester wax and oxidized polyethylene wax, higher fatty acids such as zinc stearate and their metal salts, paraffin, and higher fatty acid amides. These may be used alone or in combination of two or more. It is preferable to contain a higher fatty acid ester or a higher fatty acid amide, and it is particularly preferable to contain Montan acid ester wax.

[0051] Examples of hydrocarbon waxes include paraffin waxes having 24 or more carbon atoms, olefin waxes having 26 or more carbon atoms, alkylbenzene waxes having 28 or more carbon atoms, and microcrystalline waxes.

[0052] Examples of higher fatty acids include higher saturated fatty acids having 12 or more carbon atoms, such as lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, cerotic acid, and montanic acid, and unsaturated fatty acids having 18 or more carbon atoms, such as oleic acid, linoleic acid, linolenic acid, elaidic acid, octadecenoic acid, arachidonic acid, cadreic acid, erucic acid, and parinaric acid.

[0053] Examples of waxes obtained by deriving higher fatty acids include higher fatty acid esters, higher fatty acid amides, and higher fatty acid salts (metal soaps).

[0054] The higher fatty acid esters are esters of the above higher fatty acids with monohydric or polyhydric alcohols, such as caprylic alcohol, lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, and behenyl alcohol, and such polyhydric alcohols as ethylene glycol, propylene glycol, butanediol, glycerin, pentaerythritol, and sorbitol.

[0055] Examples of higher fatty acid esters include stearyl stearate, pentaerythritol tetrastearate, stearic acid monoglyceride, behenic acid monoglyceride, and montanic acid wax.

[0056] Examples of higher fatty acid amides include saturated higher fatty acid amides such as lauric acid amide, palmitic acid amide, stearic acid amide, and behenic acid amide; unsaturated higher fatty acid amides such as erucic acid amide, oleic acid amide, brassidic acid amide, and elaidic acid amide; and higher fatty acid bisamides such as methylene bisstearic acid amide, ethylene bisstearic acid amide, and ethylene bisoleic acid amide (including saturated or unsaturated higher fatty acid alkylamides such as higher fatty acid methylamides and higher fatty acid ethylamides).

[0057] When wax (mold release agent) is used, its content in the entire resin molding material is preferably 0.01 to 3 mass %, more preferably 0.05 to 2 mass %, which can reliably achieve the effect of improving mold releasability.

[0058] [Other ingredients] The resin composition may also contain other additives such as an antioxidant and a leveling agent, provided that the effects of the present invention are not impaired.

[0059] <Side plates (first side plate, second side plate)> The side plate 5 includes a first side plate 5a and a second side plate 5b. The first side plate 5a is an annular member attached to a first end 21 of the rotor core 20. The second side plate 5b is an annular member attached to a second end 22 of the rotor core 20. Hereinafter, when there is no need to distinguish between the first side plate 5a and the second side plate 5b, they will be described as side plates 5.

[0060] The side plate 5 is made of, for example, a resin plate (a plate-shaped cured resin composition) or a metal plate, and covers the permanent magnets 95 housed in the magnet arrangement section 29. This prevents the permanent magnets 95 from shifting position or jumping out.

[0061] <Shaft> The shaft 3 is inserted into and fixed to the shaft placement hole 25 of the rotor core 20 described above. The material of the shaft 3 is made of a round steel bar, and is selected in consideration of strength, durability, and heat transfer performance, and for example, stainless steel, nickel chromium steel, chromium molybdenum steel, etc. is used. The outer diameter of the shaft 3 is, for example, not less than 10 mm and not more than 250 mm.

[0062] <Shaft fixing structure (shaft sealing resin part)> When the shaft 3 is placed in the shaft placement hole 25, a space is formed between the shaft 3 and the wall surface of the shaft placement hole 25. A shaft sealing resin part 98 made of a cured product of the resin composition that has been filled into this space is filled. By providing the shaft sealing resin part 98, heat transfer between the rotor core 20 and the shaft 3 is improved.

[0063] The resin composition used for the shaft sealing resin portion 98 can be the same as the resin composition exemplified above for the magnet sealing resin portion 96. Note that the resin composition for the magnet sealing resin portion 96 and the resin composition for the shaft sealing resin portion 98 may be the same type or different types.

[0064] The physical properties of the cured resin composition of the shaft sealing resin portion 98 are, for example, as follows. The thermal conductivity is 0.3 W / m K or more. The lower limit of the thermal conductivity is preferably 1.0 W / m K or more, and more preferably 2.0 W / m K or more. The upper limit of the thermal conductivity is not particularly limited, but a realistic value is, for example, 10 W / m K. The glass transition temperature Tg is not less than 120° C., preferably not less than 140° C., and more preferably not less than 160° C. By setting the glass transition temperature Tg within the above range, the motor 100 can be used at high temperatures.

[0065] <Cooling air flow path inside the shaft>

[0066] The shaft cooling air flow path 60 is formed as a through-hole that penetrates the shaft 3 from one end 3d to the other end 3e. The cross-sectional shape of the through-hole is circular. The diameter of the through-hole is, for example, 5 mm or more and 200 mm or less.

[0067] <Tapered and rounded shapes at the ends of the cooling air passages inside the shaft> Fig. 8 shows an enlarged view (area B in Fig. 4) of the end 3d of the shaft 3. As shown in Fig. 8(a), the cooling air flow path 60 in the shaft, i.e., the end 3d of the through hole, has a tapered portion 62 (tapered shape). Note that, although the tapered portion 62 is provided at one end 3d of the shaft 3 here, it may also be provided at the other end 3e, or at both ends 3d, 3e.

[0068] The axial length L1 of the tapered portion 62 is, for example, 0.5 mm or more and 50 mm or less, preferably 2 mm or more and 30 mm or less, and more preferably 5 mm or more and 20 mm or less. The taper ratio of the tapered portion 62 is, for example, 0.04 or more and 2 or less, preferably 0.06 or more and 1 or less, and more preferably 0.1 or more and 0.7 or less.

[0069] By providing the tapered portion 62 in the cooling air flow path 60 in the shaft, the heat transfer structure 80 can be inserted smoothly into the cooling air flow path 60 when it is placed therein.

[0070] As shown in FIG. 8( b ), a rounded portion 63 may be provided instead of the tapered portion 62 . The round angle of the rounded portion 63 has a radius of, for example, 0.5 mm or more and 10 mm or less, preferably 2 mm or more and 8 mm or less, and more preferably 3 mm or more and 5 mm or less.

[0071] <Heat transfer structure> The heat transfer structure 80 is inserted into the inside of the cooling air flow path 60 in the shaft. The heat transfer structure 80 is configured to allow cooling air 99 to pass through. Various structures can be adopted as the heat transfer structure 80. The heat transfer structure 80 of this embodiment has a fin structure.

[0072] Fig. 5 shows a cross-sectional view of the heat transfer structure 80 arranged in the in-shaft cooling air flow path 60. Fig. 6 shows the cross-sectional shape of the heat transfer structure 80. Fig. 7 shows an exploded view of the heat transfer structure 80. The heat transfer structure 80 has a multi-layer structure formed in multiple layers in the radial direction, i.e., a configuration in which multiple cylindrical members are arranged coaxially. Specifically, the heat transfer structure 80 has, in order from the center, a first sleeve 81, an inner fin 82, a second sleeve 83, and an outer fin 84. By arranging them coaxially, the first sleeve 81, the inner fin 82, the second sleeve 83 and the outer fin 84 do not become eccentric, and the rotation of the shaft 3 can be prevented from becoming unstable.

[0073] The first sleeve 81 is a cylindrical member with a circular cross section, and is provided with a plate-like reinforcing member inside. The inner fin 82 is a cylindrical member having a ten-sided star-shaped sleeve cross section. That is, it has a shape in which ten fins are arranged in the circumferential direction. The outermost end of the inner fin 82 (star-shaped sleeve) abuts against the inner peripheral surface of the second sleeve 83, and the innermost end abuts against the outer peripheral surface of the first sleeve 81. The second sleeve 83 is a cylindrical member with a circular cross section. The outer fins 84 are cylindrical members each having a fourteen-sided star-shaped sleeve cross section. That is, they have a shape in which fourteen fins are arranged in the circumferential direction. The outermost ends of the outer fins 84 (star-shaped sleeve) abut against the flow path wall surface 65 of the in-shaft cooling air flow path 60, and the innermost ends abut against the outer peripheral surface of the second sleeve 83.

[0074] In the heat transfer structure 80, before being inserted into the intra-shaft cooling air flow path 60, the width in the direction perpendicular to the direction of insertion into the intra-shaft cooling air flow path 60 (cavity) (i.e., the outer diameter of the outer fins 84) is set to be slightly larger than the inner diameter of the intra-shaft cooling air flow path 60. As a result, when the heat transfer structure 80 is inserted into the intra-shaft cooling air flow path 60, the outer fins 84 (particularly the portions that abut against the flow path wall surfaces 65) are deformed and at least partially crushed. In other words, the outer fins 84 are urged against the flow path wall surfaces 65 of the intra-shaft cooling air flow path 60. As a result, the outer fins 84 are in reliable contact with the flow path wall surfaces 65, enabling good heat conduction from the shaft 3.

[0075] The first sleeve 81, the inner fins 82, the second sleeve 83, and the outer fins 84 are made of a metal with good thermal conductivity, such as aluminum, iron, copper, or an alloy thereof. By using these materials, the heat of the rotor core 20 (more specifically, the permanent magnets 95) can be transferred to the air 99 flowing through the in-shaft cooling air passage 60.

[0076] The heat-resistant temperature of the first sleeve 81, the inner fins 82, the second sleeve 83, and the outer fins 84 is, for example, 120°C or higher, preferably 150°C or higher, and more preferably 180°C or higher, taking into consideration the environment in which the motor 100 is used and the heat generated by the permanent magnets 95. There is no particular upper limit, but it is, for example, 250°C or lower.

[0077] The first sleeve 81 and the second sleeve 83 also function to separate the layers. From the viewpoint of maintaining this separation and ensuring that the inner fins 82 and the outer fins 84 come into proper contact with each other, it is preferable that the first sleeve 81 and the second sleeve 83 have higher rigidity than the inner fins 82 and the outer fins 84. The rigidity can be adjusted as desired by selecting the material and the structure employed.

[0078] <How to install the heat transfer structure> A method for installing the heat transfer structure 80, that is, a method for manufacturing the rotor 2 (shaft 3) having the heat transfer structure 80, will be described.

[0079] In the shaft preparation step, a shaft 3 having an internal cooling air flow path 60 penetrating in the direction of the rotation axis L and having a hollow interior is prepared. Next, in the heat transfer structure preparation step, a breathable heat transfer structure 80 is prepared. Breathable means that air 99 can pass through the interior. Furthermore, the structure of the heat transfer structure 80 is such that the amount of air 99 supplied is a generally laminar flow. Next, in the heat transfer structure insertion step, at least one heat transfer structure 80 is inserted into the in-shaft cooling air flow path 60. At this time, if at least one end of the in-shaft cooling air flow path 60 has a tapered section 62 (tapered shape) or a rounded section 63 (rounded shape), the heat transfer structure 80 can be smoothly inserted into the predetermined position. The size of the heat transfer structure 80 is made slightly larger than the inner diameter of the in-shaft cooling air flow path 60 where it will be placed, i.e., a crushing margin is provided. This causes at least a portion of the heat transfer structure 80 to be crushed against the inner wall of the in-shaft cooling air flow path 60. As a result, the heat transfer structure 80 reliably contacts the flow path wall surface 65 of the in-shaft cooling air flow path 60.

[0080] <Modification of heat transfer structure> 9 shows a heat transfer structure 80 of Modified Example 1. In the above-described embodiment, one heat transfer structure 80 is arranged in the in-shaft cooling air flow path 60. In this modified example, a plurality of heat transfer structures 80 (first to fourth heat transfer structures 80a to 80d) (four in this case) are arranged side by side in the direction of the rotation axis L. The structures (cross-sectional shapes) of the first to fourth heat transfer structures 80a to 80d may be the structures shown in FIGS. 5 and 6, etc., or may be the structures shown in the modified examples.

[0081] Furthermore, when arranging multiple heat transfer structures 80 (first to fourth heat transfer structures 80a to 80d) in the shaft cooling air flow path 60, the members of adjacent heat transfer structures 80 may be spaced apart, may be in contact with each other, or may be a mixture of contacting and spaced apart states, as shown in Figure 9.

[0082] As a modification of the heat transfer structure 80, in addition to the fin structure described above, the following modification may be adopted. (a) Heat transfer structure 80 with corrugated fins A modified example of the heat transfer structure 80 has corrugated fins made by bending a metal plate into a wave shape. (b) Heat transfer structure 80 with plate fins A modified example of the heat transfer structure 80 has plate fins formed by arranging metal plates. More specifically, the heat transfer structure 80 of this modified example has a structure in which corrugated metal plates and flat metal plates are stacked and brazed together. (c) Heat transfer structure 80 with honeycomb fins A modified example of the heat transfer structure 80 has honeycomb fins, each of which is made up of a plurality of cylindrical members separated by partition walls. Specifically, a plurality of cylindrical members each having a hexagonal cross section are assembled together to form a honeycomb cross section. (d) Heat transfer structure 80 having a porous structure A porous structure is a modified example of the heat transfer structure 80. For example, a sintered metal or a member having a three-dimensional mesh structure can be used as the porous structure. The heat transfer structure 80 of the above-described modified example employs a structure that prevents eccentricity when the shaft 3 is rotating.

[0083] <Air intake enclosure> The air inlet enclosure 40 is provided to smoothly introduce air 99 into the cooling air flow path 60 within the shaft, and is provided to surround the ends 3d, 3e of the cooling air flow path 60 within the shaft (through hole) provided in the shaft 3.

[0084] The air inlet enclosure 40 has an air inlet section 41 provided on the air 99 inlet side and an air outlet section 42 provided on the outlet side.

[0085] The air introduction part 41 is provided to surround the left end part 3d of the shaft 3 in FIG. 2. The air introduction part 41 is formed in a box shape or a cylindrical shape with a bottom, and is provided with an intake part 45 that communicates with the outside and introduces air 99. The size of the air introduction part 41 (i.e., the internal volume) is set so that the air 99 taken in from the intake part 45 can be smoothly introduced into the intra-shaft cooling air flow path 60. Furthermore, a configuration for guiding the air 99 to the intra-shaft cooling air flow path 60 may be provided inside the air introduction part 41.

[0086] The air discharge part 42 is provided to surround the end part 3e of the shaft 3 on the right side in FIG. 2. The air discharge part 42 is formed in a box shape or a cylindrical shape with a bottom, and is provided with an exhaust part 46 that communicates with the outside and introduces air 99. The size of the air discharge part 42 (i.e., the internal volume) is set so that the air 99 can be smoothly exhausted from the cooling air flow path 60 in the shaft. Note that if there is no need to reuse the air 99 or control the exhaust direction, the air discharge part 42 can be omitted.

[0087] <Air flow> The introduction and exhaust of the air 99 in the motor 100 having the above configuration will be briefly described. The air 99 is pressurized using a compressor, accumulator, or the like, and introduced into the air introduction section 41 from the intake section 45. The exhaust side (air discharge section 42 side) may be depressurized so that the air 99 is taken in. The amount of air 99 supplied is, for example, about 5 m / sec to 20 m / sec in flow velocity, and is roughly a laminar flow. The amount of air 99 supplied is set appropriately depending on the amount of heat required to be discharged.

[0088] The air 99 taken in by the air inlet portion 41 is taken into the in-shaft cooling air flow path 60 from one end 3d side of the shaft 3 (the end on the left side in FIG. 2 ), and passes through the heat transfer structure 80. As the air 99 passes through the heat transfer structure 80, the air 99 takes in heat from the heat transfer structure 80. At this time, good heat transfer is achieved by the heat transfer structure 80 having the fin structure or the like as described above.

[0089] The air 99 that has absorbed heat from the heat transfer structure 80 is discharged from the other end 3e (the right end in Figure 2) of the shaft 3 to the outside of the cooling air flow path 60 within the shaft, in this case into the inside of the air discharge section 42, and then discharged to the outside from the exhaust section 46.

[0090] <Summary of motor features and functions> The features of the above-described embodiment can be briefly summarized as follows. (1) A rotor (2) having a rotor core (20) (rotor body) formed by laminating a plurality of electromagnetic steel plates, a permanent magnet (95) (magnet) or a coil provided in the rotor core (20), and a shaft (3) provided on a rotation axis of the rotor core (20), The shaft 3 is a cooling air flow path 60 (cavity) in the shaft formed inside by a through hole penetrating in the axial direction; a heat transfer structure (80) that is provided in at least a part of the cooling air flow path (60) in the shaft and that allows cooling air (99) to pass through; (2) The rotor 2 according to (1), wherein the heat transfer structure 80 has a fin structure (inner fins 82, outer fins 84). (3) The rotor 2 according to (2), wherein the fin structure has corrugated fins formed by bending a metal plate into a wave shape. (4) The rotor 2 according to (2) or (3), wherein the fin structure has plate fins in which metal plates are arranged in a row. (5) The rotor 2 according to any one of (2) to (4), wherein the fin structure has honeycomb fins in which a plurality of cylindrical portions separated by partition walls are arranged. (6) A rotor 2 described in any one of (2) to (5), wherein the fin structure has a multi-layer structure (first sleeve 81, inner fin 82, second sleeve 83, outer fin 84) formed in multiple layers in the radial direction. (7) The rotor 2 according to (6), wherein the multi-layer structure has cylindrical sleeves (a first sleeve 81 and a second sleeve 83) that separate the layers. (8) The rotor according to any one of (1) to (7), wherein the heat transfer structure 80 has a porous structure. Examples of porous structures include sintered metal and members having a three-dimensional mesh structure. (9) The rotor 2 according to any one of (1) to (8), wherein the heat transfer structures 80 (first to fourth heat transfer structures 80a to 80d) are arranged in a plurality of rows in the axial direction. (10) A rotor 2 described in any one of (1) to (9), wherein at least a portion of the heat transfer structure 80 is biased toward the flow path wall surface 65 (inner wall) of the cooling air flow path 60 in the shaft. (11) A rotor 2 described in any one of (1) to (10), wherein at least one end of the cooling air flow path 60 (through hole) in the shaft is a tapered portion 62 (tapered shape) or a rounded portion 63 (rounded shape). (12) The rotor core 20 (rotor body) is The permanent magnet 95 (magnet), a magnet arrangement portion 29 that accommodates the permanent magnet 95; a magnet sealing resin portion 96 made of a cured resin composition filled in a space formed between the permanent magnet 95 and a wall surface of the magnet placement portion 29 when the permanent magnet 95 is accommodated in the magnet placement portion 29; and and The thermal conductivity of the cured product of the magnet sealing resin portion 96 is 0.3 W / m·K or more. A rotor 2 according to any one of (1) to (11). (13) The rotor core 20 is a shaft placement hole 25 that penetrates the rotor core 20 to the axial center and in which the shaft 3 is placed; a shaft sealing resin portion 98 made of a cured product of a resin composition filled in the space between the shaft 3 and the wall surface of the shaft arrangement hole 25 when the shaft 3 is arranged in the shaft arrangement hole 25; and The thermal conductivity of the cured product of the shaft sealing resin portion 98 is 0.3 W / m K or more. A rotor 2 according to any one of (1) to (12). (14) A motor 100 (rotating electric machine) having the rotor 2 according to any one of (1) to (13) and a stator 4, A rotating electric machine having an air introduction section 41 (first air introduction enclosure) which is arranged to surround one end of an in-shaft cooling air flow path 60 (through hole) provided in the shaft 3 of the rotor 2, and through which the air 99 passes when introducing cooling air 99 into the in-shaft cooling air flow path 60. (15) A rotating electric machine as described in (14) having an air discharge section 42 (second air introduction enclosure) that is arranged to surround the other end of the cooling air flow path 60 within the shaft and through which the air 99 passes when the air 99 is discharged from the cooling air flow path 60 within the shaft. (16) A method for manufacturing a rotor (2) having a rotor core (20) formed by laminating a plurality of electromagnetic steel plates, a permanent magnet (95) or a coil provided in the rotor core (20), and a shaft (3) provided on a rotation axis (L) of the rotor core (20), comprising: a shaft preparation step of preparing a hollow shaft (3) having an internal cooling air flow path (60) penetrating in the direction of the rotation axis (L); a heat conduction structure preparation step of preparing a breathable heat transfer structure 80; a heat transfer structure inserting step of inserting at least one of the heat transfer structures 80 into the shaft cooling air flow path 60; A method for manufacturing a rotor (2) having the above structure. (17) The method for manufacturing a rotor (2) according to (16), wherein at least one end of the shaft cooling air flow passage (60) is formed as a tapered portion (62) (tapered shape) or a rounded portion (63) (rounded shape). (18) In the heat transfer structure 80, a width in a direction perpendicular to a direction of insertion into the cavity (the cooling air flow path 60 in the shaft) is larger than an outer diameter of the cooling air flow path 60 in the shaft, The method for manufacturing a rotor (2) according to (16) or (17), wherein the heat transfer structure inserting step includes pressing at least a part of the heat transfer structure (80) against an inner wall of the shaft cooling air flow path (60).

[0091] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted. [Explanation of symbols]

[0092] 1 case 2 rotors 3 shafts 4 Stator 5 Side Plate 5a First side plate 5b Second side plate 10 Cooling water flow path 20 rotor core 20a Outer surface 25 Shaft placement hole 29 Magnet placement section 40 Air intake enclosure 41 Air intake 42 Air exhaust section 45 Intake section 46 Exhaust section 60 Cooling air flow path inside the shaft 62 Tapered section 63 Round Section 65 Channel wall 80 Heat Transfer Structure 80a First heat transfer structure 80b Second heat transfer structure 80c 3rd heat transfer structure 80d 4th heat transfer structure 81 First Sleeve 82 Inner fin 83 Second Sleeve 84 outer fin 96 Magnet sealing resin part 98 Shaft sealing resin part 99 Air 100 motor

Claims

1. A rotor having a rotor body formed by laminating a plurality of electromagnetic steel plates, a magnet or a coil provided on the rotor body, and a shaft provided on a rotation axis of the rotor body, The shaft a cavity formed therein by a through hole passing through in the axial direction; a heat transfer structure provided in at least a part of the cavity and capable of ventilating cooling air; A rotor having

2. The rotor of claim 1 , wherein the heat transfer structure comprises a fin structure.

3. The rotor according to claim 2 , wherein the fin structure has corrugated fins formed by bending a metal plate into a wave shape.

4. The rotor according to claim 2 or 3, wherein the fin structure has plate fins in which metal plates are arranged in a row.

5. The rotor according to claim 2 or 3, wherein the fin structure has honeycomb fins in which a plurality of cylindrical portions separated by partition walls are arranged.

6. The rotor according to claim 2 or 3, wherein the fin structure has a multi-layer structure formed in a plurality of layers in the radial direction.

7. The rotor according to claim 6 , wherein the multi-layer structure includes a cylindrical sleeve that separates the layers.

8. The rotor according to claim 1 , wherein the heat transfer structure has a porous structure.

9. The rotor according to claim 1 , wherein a plurality of the heat transfer structures are arranged side by side in the axial direction.

10. The rotor according to claim 1 , wherein at least a portion of the heat transfer structure is biased toward an inner wall of the cavity.

11. The rotor according to claim 1 , wherein at least one end of the through hole is tapered or rounded.

12. The rotor body includes: The magnet; a magnet arrangement section that accommodates the magnet; a magnet sealing resin portion made of a cured resin composition filled in a space formed between the magnet and a wall surface of the magnet placement portion when the magnet is placed in the magnet placement portion; and and The thermal conductivity of the cured product of the magnet sealing resin portion is 0.3 W / m K or more. A rotor according to any one of claims 1 to 3.

13. The rotor body includes: a shaft placement through-hole that penetrates the rotor body to the axial center and into which the shaft is placed; a shaft sealing resin portion made of a cured product of a resin composition filled in a space between the shaft and a wall surface of the shaft placement through hole when the shaft is placed in the shaft placement through hole; and the thermal conductivity of the cured product of the shaft sealing resin portion is 0.3 W / m K or more; A rotor according to any one of claims 1 to 3.

14. A rotating electric machine having the rotor according to any one of claims 1 to 3 and a stator, A rotating electric machine having an air inlet portion that surrounds one end of a through hole provided in a shaft of the rotor and through which cooling air passes when the air is introduced into the through hole.

15. 15. The rotating electric machine according to claim 14, further comprising an air discharge portion provided so as to surround the other end of the through hole, through which the air passes when the air is discharged from the through hole.

16. A method for manufacturing a rotor having a rotor body formed by laminating a plurality of electromagnetic steel plates, a magnet or a coil provided on the rotor body, and a shaft provided on a rotation axis of the rotor body, comprising: a shaft preparation step of preparing a hollow shaft having a through hole passing through in the axial direction; a heat transfer structure preparation step of preparing a heat transfer structure that is breathable; a heat transfer structure inserting step of inserting at least one of the heat transfer structures into the cavity; A method for manufacturing a rotor having the above structure.

17. The method for manufacturing a rotor according to claim 16 , wherein at least one end of the through hole is tapered or rounded.

18. In the heat transfer structure, a width in a direction perpendicular to a direction of insertion into the cavity is larger than an outer diameter of the cavity, The heat transfer structure inserting step includes compressing at least a portion of the heat transfer structure against an inner wall of the cavity. A method for manufacturing a rotor according to claim 16 or 17.

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