Resin manufacturing method and insulation structure manufacturing method

Abstract

To efficiently manufacture a high-performance insulation structure having high development suppressing effect of an electric tree.SOLUTION: A resin manufacturing method for manufacturing resin impregnated in an insulation structure formed on an outer peripheral portion of a conductor includes: a chemical modification step of chemically modifying a surface of nanofillers; an epoxy-resin mixing step of adding epoxy resin and a polymerization accelerator to the nanofillers and shear-mixing the same to generate a mixture; and a curing agent mixing step of mixing an acid anhydride-curing agent with the mixture after the epoxy-resin mixing step.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a resin and a method for manufacturing an insulating structure.

Background Art

[0002] Coils used in rotating electrical machines such as electric motors and generators are provided with an insulating structure that prevents the current flowing through the conductors in the coil from leaking to the outside.

[0003] As such an insulating structure, a structure is known in which an insulating tape containing mica or the like is wound around the outer peripheral portion of a conductor, and the space inside the insulating tape is impregnated with a resin containing a filler made of a metal oxide or the like. The filler functions to suppress the progress of electrical trees generated in the insulating tape and improve the insulation performance.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, conventionally, the electric field strength of the insulation of rotating electricity is about 3 kV / mm. If this can be increased, the space factor of the winding can be increased, and the single-machine output can be improved. In addition, the effect of suppressing the progress of electrical trees by the filler as described above greatly depends on the dispersibility of the filler. That is, when the dispersibility of the filler is low, the filler aggregates in the insulating structure, and the area where electrical trees are likely to progress (the area of only resin) increases, so the effect of suppressing the progress of electrical trees becomes small.

[0006] Also, the viscosity of the resin containing the filler greatly affects the productivity of the insulation structure. For example, if the viscosity of the resin increases unintentionally, it becomes difficult to impregnate the resin into an insulating tape or the like.

[0007] As described above, in order to efficiently manufacture a high-performance insulation structure, it is important to manufacture a resin with high filler dispersibility and viscosity stability.

[0008] Therefore, an object of the present invention is to provide a resin manufacturing method and an insulation structure manufacturing method that enable efficient manufacture of a high-performance insulation structure with a high effect of suppressing the progress of electrical trees.

Means for Solving the Problems

[0009] One aspect of the present invention is a resin manufacturing method for manufacturing a resin to be impregnated into an insulation structure formed on the outer peripheral portion of a conductor, the method including a chemical modification step of chemically modifying the surface of nanofiller The single and an epoxy resin mixing step of adding an epoxy resin and a polymerization accelerator to the nanofiller and shear mixing to generate a mixture, and a curing agent mixing step of mixing an acid anhydride curing agent into the mixture after the epoxy resin mixing step. step of mixing a reactive diluent with the nanofiller after the chemical modification process, and after mixing the reactive diluent

Brief Description of the Drawings

[0010]

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MODE FOR CARRYING OUT THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification, the components according to the embodiments and the descriptions of the components may be described in a plurality of expressions. The components and their descriptions are examples and are not limited by the expressions in this specification. The components may be specified by names different from those in this specification. Also, the components may be described by expressions different from the expressions in this specification.

[0012] <Configuration of Rotating Electrical Machine> FIG. 1 is a cross-sectional view showing the configuration of a rotating electrical machine 1 according to the embodiment. The rotating electrical machine 1 has a rotor 10 and a stator 20. The rotating electrical machine 1 is a component such as, for example, a motor or a generator.

[0013] The rotor 10 has a rotor shaft 11 and a rotor core 12. The rotor shaft 11 is rotatably supported by bearings 5 near both ends thereof. The bearings 5 are fixed to a bearing bracket 7 provided integrally with a frame 6 that constitutes the outer shell of the rotating electrical machine 1. The rotor core 12 is fixed to the outer peripheral surface of the rotor shaft 11 and rotates together with the rotor shaft 11.

[0014] The stator 20 has a stator core 21 and an insulating coil 22. The stator core 21 is disposed with a gap on the radially outer side of the rotor core 12. The insulating coil 22 is a member that is incorporated in the stator core 21 and generates a magnetic field essential for the rotating electrical machine 1, and an insulating structure described later is provided on its outer peripheral portion. The insulating coil 22 is assembled so as to penetrate the stator core 21.

[0015] <Configuration of Insulating Coil> FIG. 2 is a perspective view showing the configuration of the insulating coil 22 according to the embodiment. FIG. 3 is a cross-sectional view showing the configuration of the insulating coil 22 according to the embodiment.

[0016] The insulating coil 22 has a laminated conductor 31 (conductor), a turn insulation portion 33, and a main insulation portion 35. The turn insulation portion 33 and the main insulation portion 35 constitute the insulation structure of the insulating coil 22.

[0017] The laminated conductor 31 is formed by laminating a plurality of conducting wires 31A. The laminated conductor 31 according to the present embodiment is formed by bundling 14 (number of laminations 7, number of columns 2) conducting wires 31A. Note that the configuration of the laminated conductor 31 is not limited to this and should be appropriately designed according to the usage situation. The laminated conductor 31 may be constituted by, for example, more than 14 conducting wires 31A, or may be constituted by laminating only one conducting wire 31A.

[0018] A turn insulation part 33 is provided on the outer surface of each conductor 31A. As a result, the outer surface of the laminated conductor 31 is covered with the turn insulation part 33. A main insulation part 35 is provided outside the turn insulation part 33. The main insulation part 35 is configured by winding a main insulation tape 40 (tape-like member).

[0019] The main insulation tape 40 according to the present embodiment is wound spirally by a half-lap method. When the width of the main insulation tape 40 is W, the pitch of the spiral is W / 2. That is, the main insulation tape 40 is wound so as to overlap half of the main insulation tape 40 wound in the previous turn. After the winding around the entire longitudinal direction of the laminated conductor 31 is completed once, the main insulation tape 40 may be further wound so as to overlap thereon. Thereby, the main insulation tape 40 can be formed in multiple layers. The insulation performance can be improved as the number of layers of the main insulation tape 40 increases. The number of windings of the main insulation tape 40 may be appropriately selected according to the required insulation performance and the like.

[0020] FIG. 4 is a cross-sectional view schematically showing the configuration of the main insulation tape 40 according to the embodiment.

[0021] The main insulation tape 40 has a main insulation layer 41, a fiber reinforcement layer 42, and a polymer layer 43.

[0022] The main insulation layer 41 is made of a non-conductive material and is a main part for realizing the insulation function of the main insulation tape 40. The fiber reinforcement layer 42 supports the main insulation layer 41 and has a function of ensuring the strength of the entire main insulation tape 40. The polymer layer 43 contains a polymer for bonding, penetrates the fiber reinforcement layer 42, and has a function of bonding the fiber reinforcement layer 42 and the main insulation layer 41.

[0023] The main insulation layer 41 contains, for example, inorganic substances such as mica, asbestos, and porcelain powder as the main components. The fiber reinforcement layer 42 contains, for example, glass fiber, polyester fiber, etc. as the main components and is usually woven in a mesh shape. Also, the fiber reinforcement layer 42 is not limited to fibers and may be configured as a non-woven fabric or may be composed of a polymer film such as polyester or polyimide. The polymer layer 43 contains, for example, unsaturated polyester resin, epoxy resin, polyimide resin, etc. as the main components.

[0024] The thickness of the main insulation layer 41 is, for example, about 100 μm. The thickness of the fiber reinforcement layer 42 is thinner than that of the main insulation layer 41 and is often, for example, about 30 μm or less. In FIG. 4, although the polymer layer 43 is shown as a component of the main insulation tape 40, since the polymer layer 43 penetrates into the fiber reinforcement layer 42, there is almost no thickness of only the polymer layer 43. Therefore, the main insulation layer 41 and the fiber reinforcement layer 42 are usually in a state of being almost in contact with each other. The main insulation tape 40 is usually wound with the main insulation layer 41 facing the laminated conductor 31 that is the object to be insulated and the fiber reinforcement layer 42 on the outside, but the reverse may also be the case.

[0025] <Internal Structure of Main Insulation Part> FIG. 5 is a cross-sectional view schematically showing the internal structure of the main insulation part 35 according to the embodiment. In FIG. 5, a cross-section along the longitudinal direction of the laminated conductor 31 (conductor 31A) is shown. FIG. 5 shows a case where the main insulation tape 40 is wound twice and the main insulation part 35 includes a taping layer A formed by the first winding and a taping layer B formed by the second winding.

[0026] The main insulation part 35 has a main insulation layer 41 and an impregnation part 50. In each of the taping layer A and the taping layer B, the main insulation layers 41 adjacent to each other in the longitudinal direction overlap each other by half of the width. This is due to the above-described half-lap winding method.

[0027] The impregnated portion 50 is a portion formed by the penetration of a resin containing nanofillers 55 around the polymer layer 43 that joins the main insulation layer 41 and the fiber reinforcement layer 42 or around the polymer layer 43. In FIG. 5, in order to emphasize the polymer layer 43 that has penetrated into the fiber reinforcement layer 42 or around the fiber reinforcement layer 42, the thickness of the main insulation layer 41 is shown thinly, and the line indicating the fiber reinforcement layer 42 is omitted. As shown in FIG. 5, the periphery of the main insulation layer 41 is covered with the impregnated portion 50 (polymer layer 43) in which the nanofillers 55 are dispersed. Also, the resin containing the nanofillers 55 has penetrated into the main insulation layer 41 as well, but its representation is omitted in FIG. 5.

[0028] FIG. 6 is a diagram showing the effects according to the embodiment. The nanofillers 55 are non-conductive nano-sized particles, for example, particles containing metal oxides. Particles. Specific examples of the substances constituting the nanofillers 55 will be described later. It is important to select the particle diameter and the filling rate so that the nanofillers 55 are uniformly dispersed without aggregating in the resin and the distance between the particles is about 100 nm or less. In particular, the distance between the particles is important, and it is desirable to set the distance between the particles based on the particle diameter and the particle filling rate. For this reason, as shown in FIG. 6, when the distance between the nanofillers dispersed in the resin is about 100 nm or less (preferably 50 nm or less) and the filling rate is a certain level (preferably 2 wt% or more), it has been experimentally confirmed by several tests and the like that the progress of the electrical tree advancing in the epoxy resin is relatively suppressed. The suppression of the progress of the electrical tree shown in FIG. 6 refers to a state in which the shape of the advanced electrical tree grows in a bush shape, and when the progress of the electrical tree is not suppressed, it refers to a state in which several electrical trees grow in a branched (branch-like) shape in the direction of the ground electrode.

[0029] FIG. 7 is a cross-sectional view schematically showing the effects of the nanofillers 55 according to the embodiment.

[0030] In FIG. 7, a state is shown in which an electrical tree T has occurred in the impregnated portion 50. The electrical tree T is an electrical degradation phenomenon caused by the voltage applied to the laminated conductor 31 and the stator 20. When the electrical tree T progresses to reach the surface layer portion of the main insulation portion 35, insulation breakdown occurs, and the rotating electrical machine 1 will stop its operation.

[0031] The nanofillers 55 dispersed in the impregnated portion 50 have a progress suppression effect of suppressing the linear progress of the electrical tree T and reducing the progress rate of the electrical tree T. Thereby, the insulation performance of the main insulation portion 35 can be improved. Such a progress suppression effect varies strongly depending not only on the content of the nanofillers 55 but also on the dispersibility. The progress suppression effect becomes larger as the dispersibility (uniformity of dispersion) of the nanofillers 55 in the impregnated portion 50 is higher. Therefore, in order to improve the progress suppression effect (insulation performance), it is important to use a resin with high dispersibility of the nanofillers 55.

[0032] <Manufacturing method of insulation structure> FIG. 8 is a flowchart showing the procedure in the manufacturing method of the insulation structure of the insulation coil 22 according to the embodiment. FIG. 9 is a view showing the state in the first half stage of the impregnation device 60 used in the manufacturing method of the insulation structure according to the embodiment.

[0033] First, the main insulation tape 40 is wound around the laminated conductor 31 (see FIG. 2) to form the insulation coil 22 before resin impregnation (S101). Then, the insulation coil 22 before resin impregnation is inserted into the stator core 21 and assembled to form the stator unit 90 (see FIG. 9) (S102). Then, the stator unit 90 is installed in the impregnation device 60 (S103), and the inside of the impregnation device 60 is evacuated (S104).

[0034] As shown in FIG. 9, the impregnation device 60 includes an airtight container 61, an exhaust pipe 62, an exhaust valve 62A, a supply pipe 63, a supply valve 63A, and a treatment tank 64. In step S103, the stator unit 90 is installed in the treatment tank 64 placed in the airtight container 61. Then, in step S104, the inside of the airtight container 61 is evacuated. When evacuating, the supply valve 63A is closed, and the air inside the airtight container 61 is sucked by a suction device connected to the exhaust pipe 62. As a result, the inside of the insulation coil 22, the space inside the turn insulation part 33 and the main insulation tape 40 wound around it, all become in a vacuum state.

[0035] After evacuating as described above, as shown in FIG. 9, the stator unit 90 in the treatment tank 64 is immersed in the resin 47 (S105). At this time, the exhaust valve 62A is closed, and the resin 47 is supplied from the supply pipe 63 into the treatment tank 64. The resin 47 is supplied so that the entire stator unit 90 is immersed.

[0036] After immersing the stator unit 90 in the resin 47 as described above, the inside of the impregnation device 60 (airtight container 61) is pressurized (S106).

[0037] FIG. 10 is a diagram showing the state in the latter half stage of the impregnation device 60 used in the manufacturing method of the insulation structure according to the embodiment. Pressurization is performed as shown in FIG. 10 by opening the supply valve 63A and supplying the pressurized gas 65 from the supply pipe 63 into the airtight container 61. The pressurized gas 65 is preferably a substance that does not react with the resin 47, and for example, is preferably an inert gas such as nitrogen gas or dry air.

[0038] By pressurizing the inside of the airtight container 61 in this way, the resin 47 containing the nanofiller 55 is impregnated into the turn insulation part 33 of the insulation coil 22 and inside the main insulation tape 40.

[0039] Then, the stator unit 90 is taken out from the impregnation device 60 (S107), and the resin 47 impregnated inside the insulation coil 22 including the main insulation tape 40 is solidified (S108). The method for solidifying the resin 47 is determined according to the properties of the epoxy resin to be used. For example, when a thermosetting epoxy resin is used, a method of accommodating the stator unit 90 in a drying furnace at a predetermined temperature for a predetermined time is performed, and finally, the stator 20 is obtained (see FIG. 1).

[0040] Thereafter, the stator 20 is attached to the frame 6 that constitutes the outer shell. Depending on the specifications of the rotating electrical machine 1, in some cases, the insulating coil 22 may be assembled into the stator core 21 that is pre-attached to the frame 6. In this case, the assembly of the frame 6, the stator core 21, and the insulating coil 22 is treated as the stator unit 90.

[0041] <Manufacturing method of resin> Hereinafter, the manufacturing method of the resin 47 to be impregnated into the main insulation tape 40 will be described. As described above, in order to improve the effect of suppressing the progress of the electrical tree T by the nanofiller 55 (the insulation performance of the main insulation portion 35), it is necessary to form an impregnated portion 50 in which the nanofiller 55 is dispersed with high dispersibility (uniformity) in the main insulation tape 40. And in order to form such an impregnated portion 50, it is important to manufacture and use the resin 47 having high dispersibility of the nanofiller 55.

[0042] The resin 47 according to the present embodiment is a composition produced by mixing an epoxy resin, a nanofiller 55, a reactive diluent, a polymerization accelerator (curing accelerator), and an acid anhydride-based curing agent (curing agent).

[0043] The epoxy resin includes a compound that contains two or more three-membered rings composed of two carbon atoms and one oxygen atom in one molecule and can be cured. The epoxy resin includes, for example, bisphenol A type epoxy resin, alicyclic epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, novolac type epoxy resin, phenol novolac type epoxy resin, etc. as main components. The epoxy resin may contain these compounds alone or two or more of them. In particular, from the viewpoint of chemical affinity with the reactive diluent, the epoxy resin preferably contains an alicyclic epoxy resin.

[0044] The nanofiller 55 contains a non-conductive metal oxide or the like. The nanofiller 55 mainly contains, for example, alumina, silica, titanium oxide, magnesium oxide, bismuth trioxide, cerium dioxide, cobalt monoxide, copper oxide, iron trioxide, holmium oxide, indium oxide, manganese oxide, tin oxide, yttrium oxide, zinc oxide, etc. The nanofiller 55 may contain these compounds alone or two or more of them.

[0045] The reactive diluent is one that reduces the viscosity of the epoxy resin by reacting with the epoxy resin. The reactive diluent contains a compound that can become part of the skeleton in the cured product of the thermosetting resin composition by having a reactive group in the molecular skeleton. The reactive diluent mainly contains, for example, butyl glycidyl ether, 1,4-butanediol diglycidyl ether, alkylene monoglycidyl ether, alkylphenol monoglycidyl ether, polypropylene glycol diglycidyl ether, alkylene diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,12-dodecanediol diglycidyl ether, o-cresyl glycidyl ether, 1,2-epoxytetradecane, etc. The reactive diluent may contain these compounds alone or two or more of them. In particular, when the epoxy resin contains an alicyclic epoxy resin, the reactive diluent preferably contains butyl glycidyl ether.

[0046] The polymerization accelerator contains, for example, a compound that can accelerate the crosslinking reaction between an epoxy compound and an acid anhydride-based curing agent. The curing accelerator mainly contains, for example, tertiary amines, phosphorus compounds, metal chelate compounds, ammonium ion compounds, imidazole compounds, etc. The curing accelerator may contain these compounds alone or two or more of them.

[0047] The acid anhydride-based curing agent contains, for example, 4-methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, 4-methyltetrahydrophthalic anhydride, tetrabromophthalic anhydride, nadic anhydride, methyl nadic anhydride, trimellitic anhydride, pyromellitic anhydride, methyl hymic anhydride, etc. as the main components. The acid anhydride-based curing agent may contain these compounds alone or in combination of two or more.

[0048] The resin 47 contains, for example, an epoxy resin, a nanofiller 55, a reactive diluent, a polymerization accelerator, and an acid anhydride-based curing agent in the following ratios. wt% is the percentage of the concentration based on mass. Epoxy resin: 30 wt% - 60 wt% …(1) Acid anhydride-based curing agent: 30 wt% - 60 wt% …(2) Reactive diluent: 5 wt% - 30 wt% …(3) Polymerization accelerator: 0.1 - 2.0 wt% based on the mass of the epoxy resin in (1) Nanofiller: 2 wt% - 30 wt% based on the whole mixture of (1) - (3)

[0049] Figure 11 is a flowchart showing the procedure in the method for producing the resin of the embodiment. For example, first, the nanofiller 55 is mixed at a ratio of 30 wt% and the reactive diluent as a solvent at a ratio of 70 wt% (S201). Next, chemical modification of the nanofiller surface is performed (chemical modification step: S202). For example, a hydrophobizing agent for the nanofiller surface is added to the mixture produced in step S201 to perform a hydrophobization reaction. For example, -OH (hydroxyl group) on the surface of the nanofiller 55 is removed to perform hydrophobization treatment on the surface of the nanofiller 55. For example, as the hydrophobizing agent, a silane coupling agent such as hexamethyldisilazane can be cited as an example. In this case, in order to promote and stabilize the chemical modification, after mixing, stirring may be continued for a while, or after mixing and stirring, it may be left standing for a while. Furthermore, the temperature may be increased to promote the reaction.

[0050] This chemical modification process is carried out to suppress the growth of electrical trees inside the resin by suppressing the reactivity between the epoxy resin and the nanofiller 55 to be mixed later, by suppressing the reactivity on the particle surface of the nanofiller 55 (improving the pot life). This chemical modification process is, for example, a particle surface modification process, and is carried out to suppress the reactivity between the particle surface of the nanofiller 55 and the resin, thereby relaxing the stress applied to the resin in the vicinity of the nanofiller and suppressing the growth of electrical trees inside the resin. By relaxing the stress of the resin in the vicinity of the nanofiller, the generation of future microcracks is suppressed, and as a result, the generation of an uneven electric field is suppressed, and the growth of electrical trees is also suppressed. As an example of this, there are a hydrophobization treatment for removing the -OH groups present on the nanofiller surface, a method of modifying with methyl groups, ethyl groups, etc. having low reactivity on the surface, and the like. For example, in this case, the degree of hydrophobization is 24% or less, but from the viewpoint of the dispersibility of the nanofiller 55, 8 to 15% is desirable.

[0051] Next, as the shear mixing step of step S203, a resin and a polymerization accelerator are added. For example, the resin, the reactive diluent, and the polymerization accelerator together amount to 90 wt%, and the nanofiller 55 amounts to 10 wt%, and they are shear mixed to obtain a mixture having a viscosity of less than 10 P (poise: dPa·s). The shear mixing step is carried out using an appropriate apparatus capable of generating shear stress in the mixture. For example, it is carried out using a three-roll mill mixer, a planetary mixer (planetary stirrer), a Laboplastmill (registered trademark) mixer, a Miracle KCK (registered trademark) mixer, etc. In the above description, the case of performing shear mixing has been described, but it is not limited to this as long as the nanofiller 55 can be uniformly dispersed in the resin.

[0052] Next, the dispersibility of the nanofiller 55 is evaluated for the mixture generated by the shear mixing step (S203) (dispersibility evaluation step: S204). As a method for evaluating the dispersibility of the nanofiller 55, for example, there is a method of irradiating the mixture with a laser pointer.

[0053] In this case, since the nanofiller 55 in the mixture scatters the light of the laser pointer (Tyndall phenomenon), when the laser pointer is irradiated towards the mixture, the trajectory of the light may appear in the mixture. For example, when the mixture is irradiated with red light having a wavelength of 635 nm to 690 nm as the irradiation light, if the dispersibility of the nanofiller 55 is low and the particle size of the aggregate of the nanofiller 55 is larger than the wavelength, the trajectory of the irradiation light clearly appears in the mixture.

[0054] On the contrary, when the dispersibility of the nanofiller 55 is high and the particle size of the aggregate of the nanofiller 55 is smaller than the wavelength, the trajectory of the light has a low light intensity and is hardly visible. Therefore, it can be evaluated that the higher the dispersibility of the nanofiller 55 in the mixture, the lower the light intensity of the trajectory of the irradiation light appearing in the mixture.

[0055] When the mixture generated through the steps of step S201 to step S203 in the present embodiment is irradiated with red light, the trajectory of the light in the mixture is hardly visible, its light intensity is extremely low, and the dispersibility of the nanofiller 55 is very high. When using a laser pointer, the area of the mixture to move to the curing agent mixing step is divided into a mesh or lattice shape, and laser light is irradiated to all the divided areas, so that when the light intensity of the trajectory of the light appearing in the mixture for each divided unit is below a threshold value, it may be determined whether the mixture meets a predetermined dispersibility standard. The light intensity can be measured with a photometer or the like. If it is determined in the dispersibility evaluation step that the dispersibility is low and does not meet the predetermined standard (S204; low dispersibility), the mixture determined to have a low dispersibility and not meet the predetermined standard is discarded (S207), and the process returns to step S201. By doing so, it is possible to prevent a mixture with uneven dispersion from proceeding to the next process. If the quality of the upstream process is good and not necessary, steps S204 and S207 may be omitted. In addition, if the dispersibility of the mixture can be evaluated in units of the divided regions and only the specific divided regions can proceed to the next process in the manufacturing apparatus, only the regions determined to have good dispersibility may proceed to step S205, which is the next process.

[0056] Note that the method using a laser pointer is simple and convenient, but it is also possible to use various particle size measuring devices that measure the particle size from the Brownian motion of the nanofiller 55 in the mixture.

[0057] If it is determined in the dispersibility evaluation step that a predetermined standard with high dispersibility is satisfied (S204; high dispersibility), the process proceeds to the next curing agent mixing step S205. In the curing agent mixing step S205, an acid anhydride curing agent is added to and mixed with the mixture generated in the shear mixing step (S203), and then stirred.

[0058] Here, the acid anhydride curing agent is mixed in approximately the same chemical equivalent as the epoxy resin used. This curing agent mixing step is performed so that the composition reaches a predetermined viscosity (for example, a viscosity practically suitable as the resin 47 for impregnation). Also, the stirring in the curing agent mixing step can be performed using an appropriate device capable of high-speed stirring. For example, it is performed using a dispersing mixer, a concentric biaxial mixer, a planetary mixer, a bead mill mixer, etc.

[0059] Thereafter, the mixture generated in the curing agent mixing step (S205) is collected (S206). The collected mixture is used as the resin 47 for impregnation as described above.

[0060] By chemically modifying the surface of the nanofiller 55 according to the above manufacturing method, a resin 47 in which the nanofiller 55 is dispersed with high dispersibility and the stress is relaxed can be manufactured. As a result, the effect of suppressing the progress of the electrical tree T (insulation performance) by the nanofiller 55 can be improved. Further, due to the high dispersibility of the nanofiller 55, the viscosity of the resin 47 can be stabilized over a long period, and the available life of the resin 47 can be improved.

[0061] In addition, in the procedure of FIG. 11 above, after mixing the reactive diluent and the nanofiller, chemical modification of the surface of the nanofiller is carried out. However, it may also be a process of carrying out chemical modification on the nanofiller alone and then mixing the reactive diluent. For example, as the chemical modification of the nanofiller alone, high-energy ion implantation (such as plasma irradiation with argon gas, etc.) may be used, or fluorine plasma treatment, treatment with a fluorine compound, or silane coupling treatment may also be used.

[0062] <Evaluation of Electrical Tree Suppression Effect> Hereinafter, an example of comparison regarding the electrical tree suppression effect of an insulating structure impregnated with a resin manufactured by each of the manufacturing methods of the above-described embodiment and conventional example is shown.

[0063] FIG. 12 is a diagram showing a test method for the electrical tree suppression test. First, with a needle-shaped electrode 111 embedded, the resin 47 according to the embodiment was cured, and a test piece 101 having a site facing the electrode 111 as a mounting electrode was prepared.

[0064] The test piece 101 is immersed in silicone oil 102.

[0065] A high voltage (15 kVp, 18 kVp, 21 kVp) was applied from a voltage generator 112 to each electrode 111, and in the test piece 101, the length of the electrical tree was measured with a microscope. Next, a voltage was applied to a test piece 101 composed of the resin 47 by a conventional manufacturing method having a similar structure, and a comparison of the electrical tree lengths was made.

[0066] FIG. 13 is a diagram for explaining the measurement results of the electrical tree lengths of the embodiment and the conventional example. As shown in Fig. 13, in the test piece 101 impregnated with the resin 47 according to the embodiment, when the applied voltage = 15 kVp, the length of the electrical tree was 0.5 mm.

[0067] When the applied voltage = 18 kVp, the length of the electrical tree was 0.3 mm, and when the applied voltage = 21 kVp, the length of the electrical tree was 0.4 mm. In the test piece 101 impregnated with the resin 47 according to the conventional example, when the applied voltage = 15 kVp, the length of the electrical tree was 3.2 mm.

[0068] When the applied voltage = 18 kVp, the length of the electrical tree was 4.2 mm, and when the applied voltage = 21 kVp, the electrical tree extended to near the ground electrode and saturated. As described above, according to this embodiment, it was clear that the effect of suppressing the progress of the electrical tree was obtained as compared with the conventional example.

[0069] As described above, according to this embodiment, it is possible to manufacture the resin 47 having high dispersibility of the nanofiller 55 and high viscosity stability. Thereby, it becomes possible to efficiently manufacture a high-performance insulating structure capable of more surely obtaining the effect of suppressing the progress of the electrical tree.

[0070] The above-described embodiments of the present invention do not limit the scope of the invention, but are merely examples included in the scope of the invention. For example, in a certain embodiment of the present invention, changes, omissions, and additions may be made to at least a part of the specific use, structure, shape, action, and effect without departing from the gist of the invention with respect to the above-described embodiments.

Explanation of reference numerals

[0071] 1...Rotating electrical machine, 5...Bearing, 6...Frame, 7...Bearing bracket, 10...Rotor, 11...Rotor shaft, 12...Rotor core, 20...Stator, 21...Stator core, 22...Insulated coil, 31...Laminated conductor (conductor), 31A...Conducting wire, 33...Turn insulation part, 35...Main insulation part, 40...Main insulation tape (tape-shaped member), 41...Main insulation layer, 42...Fiber reinforced layer, 43...Polymer layer, 47...Resin, 50...Impregnated part, 55...Nanofiller, 60...Impregnation device, 61...Container, 62...Exhaust pipe, 62A...Exhaust valve, 63...Supply pipe, 63A...Supply valve, 64...Treatment tank, 65...Pressurized gas, 90...Stator unit, 101...Test piece, 102...Silicone oil, 111...Electrode, 112...Voltage generator, 113...Grounding electrode, T...Electric tree.

Claims

1. A method for manufacturing a resin to be impregnated into an insulating structure formed on the outer peripheral portion of a conductor, comprising: a chemical modification step of chemically modifying the surface of a single nanofiller; a step of mixing a reactive diluent with the nanofiller after the chemical modification step; an epoxy resin mixing step of adding an epoxy resin and a polymerization accelerator to the nanofiller after mixing the reactive diluent and performing shear mixing to produce a mixture; a curing agent mixing step of mixing an acid anhydride curing agent with the mixture after the epoxy resin mixing step; A resin manufacturing method comprising the above steps.

2. The chemical modification step is any one of high-energy ion implantation, fluorine plasma treatment, fluorine compound treatment, or silane coupling treatment. The resin manufacturing method according to Claim 1.

3. The chemical modification step is hydrophobization of the surface of the nanofiller, and the hydrophobization is removal of hydroxyl groups on the surface of the nanofiller. The resin manufacturing method according to Claim 2.

4. The epoxy resin includes an alicyclic epoxy resin. The resin manufacturing method according to Claim 1.

5. The method includes butyl glycidyl ether as the reactive diluent. The resin manufacturing method according to Claim 1.

6. A method for manufacturing an insulating structure formed on the outer peripheral portion of a conductor, comprising: a resin manufacturing step of manufacturing a resin containing a nanofiller; a step of impregnating a non-conductive tape-shaped member wound around the outer peripheral portion of the conductor with the resin; The resin manufacturing step includes: a chemical modification step of chemically modifying the surface of a single nanofiller; a step of mixing a reactive diluent with the nanofiller after the chemical modification step; an epoxy resin mixing step of adding an epoxy resin and a polymerization accelerator to the nanofiller after mixing the reactive diluent and performing shear mixing to produce a mixture; a curing agent mixing step of mixing an acid anhydride curing agent with the mixture after the epoxy resin mixing step; An insulating structure manufacturing method comprising the above steps. ​ ​

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