Method of producing a resin and method of producing an insulating structure

Abstract

A resin production method is a method of producing a resin used for an insulation structure formed by impregnating a conductor in a peripheral portion. The resin production method includes a dispersion liquid mixing step of mixing an epoxy resin and a dispersion liquid in which a nanofiller is dispersed in a reactive diluent that reduces a viscosity of the epoxy resin by reacting with the epoxy resin, and a curing agent mixing step of mixing a composition produced in the dispersion liquid mixing step and a curing agent used for curing the epoxy resin. The epoxy resin includes, for example, an alicyclic epoxy resin.

Description

Technical Field

[0001] This invention relates to a method for producing resin and a method for producing insulating structures. Background Technology

[0002] The coils used in rotating electrical machines, such as electric motors or generators, are provided with an insulating structure to prevent the current flowing through the conductors in the coils from leaking to the outside.

[0003] As described above, an insulating structure is known where an insulating tape containing mica or the like is wrapped around the outer periphery of a conductor, and the spaces within the insulating tape are impregnated with a resin containing fillers such as metal oxides. The function of the filler is to suppress the development of electrical trees generated in the insulating tape, thereby improving insulation performance.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: US 2013 / 0131218 A Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] The effectiveness of the fillers in inhibiting electrical tree development largely depends on their dispersibility. When the dispersibility of the fillers is low, they agglomerate in the insulation structure, increasing the area where electrical trees are prone to develop (the area containing only resin), thus reducing the effectiveness of inhibiting electrical tree development.

[0009] The viscosity of filler-containing resins has a significant impact on the productivity of insulation structures. For example, when the viscosity of the resin unintentionally increases, it becomes difficult to perform operations such as impregnating insulating tape with the resin.

[0010] As mentioned above, in order to efficiently produce high-performance insulation structures, it is important to produce a resin with high filler dispersibility and high viscosity stability.

[0011] Therefore, the object of the present invention is to provide a resin production method and an insulation structure production method that can efficiently produce high-performance insulation structures.

[0012] Methods for solving problems

[0013] One aspect of the present invention is a method for producing a resin for impregnating an insulating structure formed on the outer peripheral portion of a conductor, the method comprising: a dispersion mixing step of mixing an epoxy resin with a dispersion in which nanofillers are dispersed in a reactive diluent, the reactive diluent reducing the viscosity of the epoxy resin by reacting with the epoxy resin; and a curing agent mixing step of mixing the composition produced in the dispersion mixing step with a curing agent for curing the epoxy resin. Attached Figure Description

[0014] Figure 1 This is a cross-sectional view showing the structure of the rotary electric machine according to the embodiment;

[0015] Figure 2 This is a perspective view showing the structure of the insulated coil according to the embodiment;

[0016] Figure 3 This is a cross-sectional view showing the structure of the insulated coil according to the embodiment;

[0017] Figure 4 This is a schematic cross-sectional view showing the structure of the main insulating tape according to the embodiment;

[0018] Figure 5 It is a schematic cross-sectional view showing the internal structure of the main insulation portion according to the embodiment;

[0019] Figure 6 This is a schematic cross-sectional view illustrating the effect of the nanofiller according to the embodiments;

[0020] Figure 7 This is a flowchart illustrating the steps in a method for producing an insulating structure for an insulated coil according to an embodiment.

[0021] Figure 8 This is a diagram showing the state of the first half of the impregnation apparatus used in the method for producing an insulating structure according to the embodiment;

[0022] Figure 9 This is a diagram showing the state of the impregnation apparatus used in the method for producing an insulating structure according to the embodiment;

[0023] Figure 10 This is a flowchart illustrating the steps in the resin production method according to the embodiments;

[0024] Figure 11 This is a graph showing the results of observing the sample extracted from the impregnated portion formed by the resin comprising the embodiment using a transmission microscope;

[0025] Figure 12It means to Figure 11 A graph showing a portion of the results magnified 10 times;

[0026] Figure 13 This is a flowchart illustrating the steps in the resin production method according to the comparative example;

[0027] Figure 14 This is a graph showing the results of observing the sample extracted from the resin-impregnated portion containing the comparative example using a transmission microscope;

[0028] Figure 15 It means to Figure 14 A graph showing a portion of the results magnified 10 times;

[0029] Figure 16 This is a cross-sectional view schematically illustrating the effect of the nanofiller according to the comparative example;

[0030] Figure 17 It is a graph comparing the time-varying viscosity of the resin according to the embodiments with the time-varying viscosity of the resin according to the comparative examples; and

[0031] Figure 18 This is a graph comparing the electric field versus time characteristics of an insulating structure produced using the resin of the embodiment, the electric field versus time characteristics of an insulating structure produced using the resin of the first comparative example, and the electric field versus time characteristics of an insulating structure produced using the resin of the second comparative example. Detailed Implementation

[0032] Embodiments of the present invention will now be described with reference to the accompanying drawings. In this specification, components and their descriptions according to the embodiments may be described using various expressions. The components and their descriptions are exemplary and not limited to the statements in this specification. The components may also be identified by names different from those in this specification. Furthermore, the components may be described using expressions different from those used in this specification.

[0033] <Structure of a Rotary Electric Machine>

[0034] Figure 1 This is a cross-sectional view showing the structure of the rotary motor 1 according to the embodiment.

[0035] The rotating electric machine 1 includes a rotor 10 and a stator 20. The rotating electric machine 1 is an assembly such as an electric motor or a generator.

[0036] The rotor 10 includes a rotor shaft 11 and a rotor core 12. The rotor shaft 11 is rotatably axially supported near both ends by bearings 5. The bearings 5 ​​are fixed to bearing supports 7, which integrates a frame 6 that forms the outer frame of the rotary motor 1. The rotor core 12 is fixed to the outer circumferential surface of the rotor shaft 11 and rotates together with the rotor shaft 11.

[0037] The stator 20 includes a stator core 21 and an insulated coil 22. The stator core 21 is disposed radially outward from the rotor core 12, with a gap between them. The insulated coil 22 is a component assembled in the stator core 21 and generating the magnetic field necessary for the rotating motor 1, and has an insulating structure, described later, on its outer periphery. The insulated coil 22 is assembled to penetrate the stator core 21.

[0038] Construction of Insulated Coils

[0039] Figure 2 This is a perspective view showing the structure of the insulated coil 22 according to the embodiment. Figure 3 This is a cross-sectional view showing the structure of the insulated coil 22 according to the embodiment.

[0040] The insulated coil 22 includes 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 insulated coil 22.

[0041] The laminated conductor 31 is formed by laminating multiple wires 31A. According to this embodiment, the laminated conductor 31 is configured by bundling 14 wires 31A (lamination count: 7, column count: 2). Note that the configuration of the laminated conductor 31 is not limited to this and should be appropriately designed according to the application. For example, the laminated conductor 31 may include more than 14 wires 31A, or it may be configured to laminate only one wire 31A.

[0042] Turn insulation portion 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 turn insulation portion 33. Main insulation portion 35 is provided outside the turn insulation portion 33. Main insulation portion 35 is configured to be wrapped with main insulating tape 40 (tape member).

[0043] According to this embodiment, the main insulating tape 40 is spirally wound using a half-lap method. When the width of the main insulating tape 40 is W, the spiral pitch is W / 2. That is, the main insulating tape 40 is wound so that it overlaps half of the previously wound main insulating tape 40. After one turn around the laminated conductor 31 in the entire longitudinal direction, the main insulating tape 40 is wound to further overlap it. Therefore, the main insulating tape 40 can form a multi-layer shape. As the number of layers of the main insulating tape 40 increases, the insulation performance can be improved. The number of windings of the main insulating tape 40 can be appropriately selected according to the required insulation performance, etc.

[0044] Figure 4 This is a schematic cross-sectional view illustrating the structure of the main insulating tape 40 according to the embodiment.

[0045] The main insulating tape 40 includes a main insulating layer 41, a fiber reinforcement layer 42, and a polymer layer 43.

[0046] The main insulation layer 41 is made of a non-conductive material and is the main part that enables the main insulating tape 40 to perform its insulating function. The fiber reinforcement layer 42 supports the main insulation layer 41 and ensures the overall strength of the main insulating tape 40. The polymer layer 43 contains the bonding polymer, permeates the fiber reinforcement layer 42, and functions to bond the fiber reinforcement layer 42 and the main insulation layer 41.

[0047] The main insulating layer 41 comprises inorganic materials such as mica, asbestos, or ceramic powder as its main component. The fiber reinforcing layer 42 comprises materials such as glass fiber and polyester fiber as its main component and is typically woven into a mesh shape. Furthermore, the fiber reinforcing layer 42 is not limited to fibers and can be formed as a nonwoven fabric or a polymer film such as polyester or polyimide. The polymer layer 43 comprises materials such as unsaturated polyester resin and epoxy resin as its main component.

[0048] The thickness of the main insulating layer 41 is, for example, about 100 μm. The thickness of the fiber reinforcement layer 42 is thinner than the thickness of the main insulating layer 41, and for example, in most cases, it is less than 30 μm. Figure 4 In this design, polymer layer 43 is represented as a component of the main insulating tape 40, but because polymer layer 43 is embedded in fiber reinforcement layer 42, polymer layer 43 has almost no thickness. Therefore, main insulating layer 41 and fiber reinforcement layer 42 are usually in almost contact with each other. Typically, when wrapping the main insulating tape 40, main insulating layer 41 faces the laminated conductor 31 to be insulated, and fiber reinforcement layer 42 faces outward, but in some cases, the opposite can be used.

[0049] <Internal structure of the main insulation section>

[0050] Figure 5 This is a schematic cross-sectional view showing the internal structure of the main insulating portion 35 according to the embodiment.

[0051] Figure 5 A cross-section along the longitudinal direction of the laminated conductor 31 (wire 31A) is shown. Figure 5 This illustrates a case where the main insulating tape 40 is wound twice, and the main insulating portion 35 includes a tape layer A formed by the first winding and a tape layer B formed by the second winding.

[0052] The main insulation portion 35 includes a main insulation layer 41 and an impregnated portion 50. In each of the tape layers A and B, the main insulation layers 41 that are adjacent to each other in the longitudinal direction overlap each other by half a width. This is due to the half-lap winding method.

[0053] The impregnated portion 50 is formed by permeating a resin including nanofiller 55 into or around the polymer layer 43, wherein the polymer layer 43 bonds the main insulating layer 41 and the fiber reinforcement layer 42. Figure 5 In order to emphasize the fiber reinforcement layer 42 or the polymer layer 43 formed by immersion around the fiber reinforcement layer, the thickness of the main insulation layer 41 is shown as thin, and the line representing the fiber reinforcement layer 42 is omitted. Figure 5 As shown, the outer periphery of the main insulating layer 41 is covered with an impregnated portion 50 (polymer layer 43) in which nanofillers 55 are dispersed. Furthermore, the resin containing the nanofillers 55 also impregnates the main insulating layer 41, but its description is as follows: Figure 5 The text has been omitted.

[0054] The nanofiller 55 comprises non-conductive nanoscale particles, such as particles containing metal oxides. The particle size of the nanofiller 55 is preferably less than or equal to 50 nm. Specific examples of the materials constituting the nanofiller 55 will be described below.

[0055] Figure 6 This is a cross-sectional view schematically illustrating the effect of the nanofiller 55 according to the embodiment.

[0056] Figure 6 The diagram illustrates the state in which electrical trees T are formed in the impregnated portion 50. Electrical trees T are a phenomenon of electrical degradation caused by voltage applied to the laminated conductor 31 and the stator 20. When the electrical trees T develop and reach the surface portion of the main insulation portion 35, dielectric breakdown occurs, and the rotating motor 1 stops operating.

[0057] The nanofiller 55 dispersed in the impregnation portion 50 has a development-inhibiting effect, suppressing the linear development of electrical trees T and reducing the development rate of electrical trees T, thereby improving the insulation performance of the main insulation portion 35. This development-inhibiting effect depends not only on the content of the nanofiller 55 but also strongly on its dispersibility. The development-inhibiting effect is enhanced as the dispersibility (uniformity of dispersion) of the nanofiller 55 in the impregnation portion 50 increases. Therefore, to improve the development-inhibiting effect (insulation performance), it is important to use a resin with highly dispersible nanofiller 55.

[0058] <Production Method of Insulation Structure>

[0059] Figure 7 This is a flowchart illustrating the steps in the method for producing the insulation structure of the insulated coil 22 according to the embodiment. Figure 8 This is a diagram showing the state of the first half of the impregnation apparatus 60 used in the method for producing an insulating structure according to the embodiment. Figure 9 This is a diagram showing the state of the impregnation apparatus 60 used in the method for producing an insulating structure according to the embodiment, in the latter half of the stage.

[0060] First, wrap the main insulating tape 40 around the laminated conductor 31 (see...). Figure 2 This forms the pre-resin-impregnated insulating coil 22 (S101). Then, the pre-resin-impregnated insulating coil 22 is inserted into the stator core 21 and assembled to form the stator unit 90 (see...). Figure 8 (S102). Thereafter, the stator unit 90 is installed in the impregnation apparatus 60 (S103), and the impregnation apparatus 60 is evacuated (S104).

[0061] like Figure 8 As shown, the impregnation apparatus 60 includes a container 61, an exhaust pipe 62, an exhaust valve 62A, a supply pipe 63, a supply valve 63A, and a processing tank 64. In step S103, the stator unit 90 is installed in the processing tank 64 located within the container 61. Next, in step S104, a vacuum is created in the container 61. When evacuation is performed, the supply valve 63A is closed, and air in the container 61 is drawn in by a suction device connected to the exhaust pipe 62. As a result, the interior of the insulated coil 22 is completely under vacuum, even in the space of the turn insulation portion 33 and the main insulating tape 40 wrapped around it.

[0062] After a vacuum is generated as described above, such as Figure 9 As shown, the stator unit 90 in the treatment tank 64 is immersed in resin 47 (S105). At this time, the exhaust valve 62A is closed, and resin 47 is supplied into the treatment tank 64 from the supply pipe 63. Resin 47 is supplied to immerse the entire stator unit 90.

[0063] After immersing the stator unit 90 in the resin 47 as described above, the pressure in the impregnation apparatus 60 (container 61) is increased (S106). Figure 9 As shown, pressure is increased by opening the supply valve 63A and supplying pressurized gas 65 from the supply pipe 63 to the container 61. The pressurized gas 65 is preferably a substance that does not react with the resin 47, and is preferably an inert gas, such as nitrogen or dry air. Increasing the pressure within the container 61 causes the resin 47, containing the nanofiller 55, to impregnate the turn insulation portion 33 of the insulated coil 22 and the main insulating tape 40.

[0064] Then, the stator unit 90 is removed from the impregnation apparatus 60 (S107), and the resin 47 impregnated in the insulating coil 22 containing the main insulating tape 40 is cured (S108). The method for curing the resin 47 is determined based on the properties of the epoxy resin used. For example, when a thermosetting epoxy resin is used, a method is employed to place the stator unit 90 in a drying oven at a predetermined temperature for a predetermined time, and finally obtain the stator 20 (see...). Figure 1 Subsequently, the stator 20 is attached to the frame 6 that forms the outer frame. According to the specifications of the rotary motor 1, the insulated coil 22 can be assembled in the stator core 21 previously connected to the frame 6. In this case, the assembly of the frame 6, the stator core 21, and the insulated coil 22 is treated as a stator unit 90.

[0065] (Resin production methods)

[0066] The following describes a method for producing a resin 47 impregnated in a main insulating tape 40. As described above, in order to improve the effect of the nanofiller 55 in suppressing the development of electrical tree branches T (the insulation performance of the main insulating portion 35), it is necessary to form an impregnated portion 50 in the main insulating tape 40 in which the nanofiller 55 is dispersed with high dispersibility (uniformity). In order to form such an impregnated portion 50, it is important to produce and use a resin 47 having highly dispersed nanofiller 55.

[0067] According to this embodiment, resin 47 is a composition produced by mixing epoxy resin, nanofiller, reactive diluent and anhydride-based curing agent (curing agent).

[0068] The epoxy resin comprises a compound having two or more three-membered rings, each consisting of two carbon atoms and one oxygen atom, in one molecule, and is curable. 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, phenolic varnish type epoxy resin, and phenolic varnish type epoxy resin as main components. The epoxy resin may contain these compounds alone or in combination of two or more of the aforementioned compounds. Specifically, from the perspective of chemical affinity with reactive diluents, the epoxy resin preferably comprises an alicyclic epoxy resin.

[0069] The nanofiller comprises non-conductive metal oxides, etc. For example, the nanofiller may contain aluminum oxide, silicon dioxide, titanium oxide, magnesium oxide, bismuth trioxide, cerium dioxide, cobalt monoxide, copper oxide, iron oxide, holmium oxide, indium oxide, manganese oxide, tin oxide, yttrium oxide, zinc oxide, etc., as main components. The nanofiller may contain these compounds alone or in combination of two or more of the aforementioned compounds. The surface of the nanofiller may be modified with a coupling agent to improve its dispersibility in epoxy resin, prevent re-aggregation, and improve adhesion, etc.

[0070] The reactive diluent (also known as a "reactive diluent") reduces the viscosity of the epoxy resin by reacting with it. The reactive diluent comprises a compound that, through its active groups in its molecular backbone, can become part of the backbone of the cured product of the thermosetting resin composition. The reactive diluent may contain, 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-dodecyl glycol diglycidyl ether, o-tolyl glycidyl ether, 1,2-epoxytetradecane, etc., as a main component. The reactive diluent may contain these compounds alone or in combination of two or more of these compounds. Specifically, when the epoxy resin comprises an alicyclic epoxy resin, the reactive diluent preferably contains butyl glycidyl ether.

[0071] The anhydride-based curing agent may contain, for example, 4-methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, 4-methyltetrahydrophthalic anhydride, tetrabromophthalic anhydride, nadic anhydride, methylnadic anhydride, trimellitic anhydride, pyromellitic anhydride, methylhymic anhydride, etc., as main components. The anhydride-based curing agent may contain these compounds alone, or a combination of two or more of the aforementioned compounds.

[0072] Curing accelerators can be used to accelerate the reaction in the curing (hardening) step of resin 47 in equipment such as drying ovens. For example, the curing accelerator contains a compound capable of accelerating the crosslinking reaction between the epoxy compound and the anhydride-based curing agent. The curing accelerator may contain, for example, metal chelate compounds, ammonium ion compounds, imidazole compounds, etc., as main components. The curing accelerator may comprise these compounds alone or a combination of two or more of these compounds.

[0073] Resin 47, for example, contains epoxy resin, nanofiller, reactive diluent and anhydride-based curing agent in the following proportions.

[0074] Epoxy resin: 30wt% to 60wt% (1)

[0075] Anhydride-based curing agent: 30wt% to 60wt% (2)

[0076] Reactive diluent: 5 wt% to 30 wt% (3)

[0077] Nanofiller: 2 wt% to 30 wt% relative to the total mixture of (1) to (3).

[0078] Figure 10This is a flowchart illustrating the steps in the method for producing resin 47 according to the embodiment.

[0079] First, a dispersion of the nanofiller in a reactive diluent is prepared (S201). Next, the epoxy resin is mixed with the dispersion prepared in step S201 (dispersion mixing step: S202). Then, the composition produced in step S202 is mixed with an anhydride-based curing agent (curing agent mixing step: S203). Finally, the composition produced in step S203 is collected as resin 47 (S204).

[0080] As described above, the resin 47 produced according to the above method is used as the resin 47 impregnated in the space of the main insulating tape 40 wrapped around the insulating coil 22.

[0081] The above description does not specify the steps for using a curing accelerator, but a curing accelerator may be used if necessary.

[0082] (Evaluation of the dispersibility of nanofillers)

[0083] The following section evaluates the dispersibility of nanofiller 55 in impregnation portion 50 when the main insulating tape 40 is impregnated with resin 47 produced according to the production method of this embodiment.

[0084] Figure 11 This is a graph showing the results of observing the sample extracted from the impregnated portion 50 formed from the resin 47 of the embodiment using a transmission microscope. Figure 12 It means to Figure 11 The image shown is a partial result magnified 10 times.

[0085] Here is an example illustrating a case where the proportion of nanofiller 55, which contains silica as the main component, is about 5 wt% relative to the entire mixture of the above components (1) to (3). Figure 11 and Figure 12 The diagram shows a state where the nanofiller 55 is almost non-aggregated, and where the nanofiller 55 with a particle size of approximately 15 nm is uniformly dispersed. Due to the high dispersibility of the nanofiller 55, the following is achieved: Figure 6 The high level of inhibition of electrical tree T development is shown.

[0086] Here, the case containing the resin 47 described in this embodiment will be compared with the case containing the resin of the comparative example.

[0087] Figure 13 This is a flowchart illustrating the steps in the resin production method according to the comparative example.

[0088] In the production method according to the comparative example, the nanofiller is first mixed with epoxy resin (S301). This mixing is typically performed using equipment such as a planetary mixer, a three-roll mixer, or a bead mill. Then, the reactive diluent is mixed with the composition (mixture) generated in step S301 (S302). Next, an anhydride-based curing agent is mixed with the composition generated in step S302 (S303). Finally, the composition generated in step S303 is collected as a resin (S204).

[0089] In the same manner as in this embodiment, a resin-impregnated main insulating tape produced according to the production method described in the comparative example was used to form an impregnated portion, and the dispersibility of the nanofiller in the impregnated portion was evaluated.

[0090] Figure 14 This is a graph showing the results of observing the sample extracted from the resin-impregnated portion containing the comparative example using a transmission microscope. Figure 15 It means to Figure 14 The image shown is a partial result magnified 10 times.

[0091] Figure 14 and Figure 15 The aggregation and clustering of nanofillers are shown. Furthermore, it can be observed that the short or long diameters of the clusters reach tens to hundreds of nm.

[0092] Figure 16 This is a cross-sectional view schematically illustrating the effect of the nanofiller 101 according to the comparative example.

[0093] like Figure 16 As shown, since the nanofiller 101 described according to the comparative example is clustered, a relatively extensive non-existent region (a region containing only resin) without the nanofiller 101 is formed in the impregnated portion 111. Electrical trees T are likely to develop more linearly along such a non-existent region. Therefore, the effect of the nanofiller 101 in inhibiting the development of electrical trees T is less than that of a nanofiller 101 containing... Figure 6 The resin 47 shown is according to this embodiment.

[0094] (Evaluation of the viscosity stability of the resin)

[0095] The viscosity stability of resin 47 produced according to the production method described in this embodiment will be evaluated below.

[0096] The viscosity of the resin containing nanofiller 55 increases over time. For example, in the case of resin 47 containing thermosetting epoxy resin, the viscosity gradually increases over time even at environments below the curing temperature, and the resin can no longer be used when the viscosity exceeds a certain limit. The period of time before resin 47 reaches its limit after production is referred to as the pot life. It is economically desirable that a single batch of resin 47 can process as many stator units 90 of the rotating motor 1 as possible. Therefore, it is ideal to have a pot life as long as possible. That is, the slower the rate of this unintended increase in viscosity, the better. The time-varying trend of the viscosity of resin 47 depends on the dispersibility of the nanofiller 55 contained in resin 47.

[0097] Figure 17 This is a graph comparing the time-varying viscosity of resin 47 according to the embodiment with the time-varying viscosity of resin according to the comparative example.

[0098] exist Figure 17 In the diagram, the four lines A1, A2, A3, and A4 on the lower side represent the time-varying viscosity of the resin 47 according to this embodiment. The resin 47 illustrated here uses, for example... Figure 10 The production method shown describes the production of a resin comprising an alicyclic epoxy resin as an epoxy resin, tetrahydrophthalic anhydride as an anhydride-based curing agent, alkylene monoglycidyl ether as a reactive diluent, and titanium dioxide as nanofiller 55, mixed in a ratio of approximately 40:40:15.5 (wt%). The resulting mixture contains 5 wt%, 10 wt%, 15 wt%, and 20 wt% titanium dioxide with a particle size of approximately 15 nm. Line A1 shows the case where the titanium dioxide (nanofiller 55) content is 5 wt%, line A2 shows the case where the titanium dioxide content is 10 wt%, line A3 shows the case where the titanium dioxide content is 15 wt%, and line A4 shows the case where the titanium dioxide content is 20 wt%.

[0099] exist Figure 17 In the diagram, the four lines at the top, B1, B2, B3, and B4, represent the time-varying viscosity of the resin in the comparative example. The resin illustrated here comprises an alicyclic epoxy resin as an epoxy resin, tetrahydrophthalic anhydride as an anhydride-based curing agent, alkylene monoglycidyl ether as a reactive diluent, and titanium dioxide as nanofiller 55, and is obtained through processes such as... Figure 13The production method shown uses a mixture of alicyclic epoxy resin, tetrahydrophthalic anhydride, and alkylene monoglycidyl ether in a ratio of approximately 40:40:15.5 (wt%). The resulting mixture comprises 5 wt%, 10 wt%, 15 wt%, and 20 wt% titanium dioxide with a particle size ranging from approximately 10 nm to several hundred nm. Line B1 shows the case with a titanium dioxide (nanofiller) content of 5 wt%, line B2 shows the case with a titanium dioxide content of 10 wt%, line B3 shows the case with a titanium dioxide content of 15 wt%, and line B4 shows the case with a titanium dioxide content of 20 wt%.

[0100] like Figure 17 As shown, compared to the viscosity of the resin described in the comparative example, the viscosity of the resin 47 according to this embodiment gradually and slowly increases over time. This is because the nanofiller aggregates and clusters in the resin described in the comparative example, while the nanofiller 55 is uniformly dispersed in the resin 47 according to this embodiment. As described above, the production method according to this embodiment can maintain a low viscosity for a long time, thus making it possible to provide a resin 47 with a long service life (potential life).

[0101] (Insulation life evaluation)

[0102] The insulation life of the insulation structure manufactured using resin 47 produced by the production method described in this embodiment will be evaluated below.

[0103] Figure 18 This is a graph comparing the electric field versus time characteristics of an insulating structure produced using resin 47 of the embodiment, the electric field versus time characteristics of an insulating structure produced using resin of the first comparative example, and the electric field versus time characteristics of an insulating structure produced using resin of the second comparative example.

[0104] exist Figure 18 In the text, line A indicates the use of resin 47 (and) according to this embodiment. Figure 17 The electric field versus time characteristics of the insulation structure produced using the resin corresponding to the center line A1. Line B indicates the use of the resin described in the first comparative example (using, for example...). Figure 13 The resin produced by the production method shown: with Figure 17 The electric field versus time characteristics of the insulation structure produced using the resin (corresponding to line B1) are shown. Line C indicates the electric field versus time characteristics of the insulation structure produced using the resin (excluding the nanofiller) described in the second comparative example.

[0105] When evaluating the long-term voltage-life characteristics of the insulation structure of the rotating electric machine 1, the lifetime of three points (E1, E2, E3) with an electric field higher than E relative to the electric field E (interface voltage / insulation thickness) of the rotating electric machine 1 in actual use is first determined experimentally, and these three points are approximated linearly. This approximate straight line is called the electric field-time characteristic, and when the rotating electric machine 1 is actually running, the lifetime in the required electric field can be predicted by extrapolating the electric field-time approximation straight line to a lower electric field side closer to the electric field, thereby estimating the service life.

[0106] The results of this embodiment based on the above method are as follows: Figure 18 As shown. Each point represents the average value of five coils obtained under the same conditions (63% of the Weibull distribution). Taking 5 kV / mm as a low electric field as an example, the lifespan of the resin included in the first comparative example (Figure B) is approximately twice that of the resin included in the second comparative example (Figure C), but the lifespan of the resin 47 included in this embodiment (Figure A) is approximately 100 times that of the resin included in the second comparative example (Figure C). As described above, this is because the nanofiller 55 according to this embodiment has high dispersibility and its effect in suppressing the development of electrical tree T is greater than that of the first comparative example.

[0107] <Case where reactive diluents are not included>

[0108] As described above, the method for producing resin according to this embodiment includes the use of a reactive diluent, which is one of its features. A third comparative example of producing a resin containing nanofillers using a diluent other than a reactive diluent will be described here.

[0109] In the third comparative example, a dispersion of the nanofiller in a diluent such as acetone, methyl ethyl ketone, or alcohol was mixed with an epoxy resin (epoxy resin, curing agent, or a mixture of both). The mixture of dispersion and epoxy resin was then subjected to heating or vacuum defoaming, or heating and vacuum defoaming, to remove the diluent from the entire mixture. The method described in the third comparative example can produce a resin containing the nanofiller.

[0110] However, in the third comparative example, it is highly likely that an unexpected chemical reaction occurred during the process of mixing the dispersion (a diluent containing nanofillers, such as acetone) with epoxy resin to generate a liquid resin, leading to increased viscosity and deterioration of insulation performance. Furthermore, the third comparative example involves a complex process and increased costs due to the need for a process to remove the diluent (heating, vacuum defoaming, or a combination of both).

[0111] On the other hand, according to this embodiment, the problems in the third comparative example do not occur, and high-quality resin 47 can be produced relatively easily and at low cost.

[0112] As described above, according to this embodiment, a resin 47 with high dispersibility and high viscosity stability of the nanofiller 55 can be produced. This allows for the efficient production of high-performance insulating structures. Furthermore, it may be unnecessary to use expensive equipment for dispersing the nanofiller 55, such as planetary mixers, three-roll mixers, or bead mills.

[0113] The above embodiments of the present invention do not limit the scope of the present invention, but are merely examples included within the scope of the present invention. For example, in the embodiments of the present invention, at least a part of the specific application, structure, shape, operation, and effect may be changed, omitted, or added to the above embodiments without departing from the spirit of the present invention.

[0114] Letter or number description

[0115] 1 Rotary electric motor

[0116] 5 bearings

[0117] 6 Framework

[0118] 7 Bearing bracket

[0119] 10 rotors

[0120] 11 Rotor shaft

[0121] 12 Rotor core

[0122] 20 stators

[0123] 21 Stator Core

[0124] 22 Insulated Coils

[0125] 31. Laminated conductor (conductor)

[0126] 31A conductor

[0127] 33 turns of insulation

[0128] 35 Main insulation section

[0129] 40 Main insulating tape (strip component)

[0130] 41 Main Insulation Layer

[0131] 42 Fiber Reinforced Layer

[0132] 43 Polymer layer

[0133] 47 Resin

[0134] 50 Impregnated portion

[0135] 55 nanometer filler

[0136] 60 Impregnation apparatus

[0137] 61 Containers

[0138] 62 Exhaust pipe

[0139] 62A exhaust valve

[0140] 63 Supply Management

[0141] 63A Supply Valve

[0142] 64 processing tanks

[0143] 65 Pressurized Gas

[0144] 90 stator units

[0145] T electric tree branches

Claims

1. A method for producing a resin used to impregnate an insulating structure formed on the outer peripheral portion of a conductor, the method comprising: The dispersion mixing step involves mixing epoxy resin with a dispersion in which nanofillers are dispersed in a reactive diluent, which reduces the viscosity of the epoxy resin by reacting with it. as well as A curing agent mixing step in which the composition produced in the dispersion mixing step is mixed with a curing agent for curing the epoxy resin; The resin comprises the epoxy resin, the nanofiller, the reactive diluent, and the curing agent in the following proportions. Epoxy resin: 30 wt% to 60 wt% (1) Anhydride-based curing agent: 30 wt% to 60 wt% (2) Reactive diluent: 5 wt% to 30 wt% (3) Nanofiller: 2 wt% to 30 wt% relative to the entire mixture of (1) to (3).

2. The method for producing resin according to claim 1, wherein, The epoxy resin includes alicyclic epoxy resin.

3. The method for producing resin according to claim 2, wherein, The reactive diluent comprises at least one of alkylene monoglycidyl ether, alkylene diglycidyl ether, 1,12-dodecyl diol diglycidyl ether, and 1,2-epoxytetradecane.

4. The method for producing resin according to any one of claims 1 to 3, wherein, The particle size of the nanofiller in the dispersion is less than or equal to 50 nm.

5. A method for producing an insulating structure, said insulating structure being formed on the outer periphery of a conductor, said method comprising: Resin production steps for producing resins containing nanofillers; as well as The step of impregnating a non-conductive strip-shaped component wound around the outer periphery of the conductor in the resin; wherein... The resin production steps include: A dispersion mixing step involves mixing epoxy resin with a dispersion in which the nanofiller is dispersed in a reactive diluent, the reactive diluent reducing the viscosity of the epoxy resin by reacting with it; and A curing agent mixing step in which the composition produced in the dispersion mixing step is mixed with a curing agent for curing the epoxy resin; The resin comprises the epoxy resin, the nanofiller, the reactive diluent, and the curing agent in the following proportions. Epoxy resin: 30 wt% to 60 wt% (1) Anhydride-based curing agent: 30 wt% to 60 wt% (2) Reactive diluent: 5 wt% to 30 wt% (3) Nanofiller: 2 wt% to 30 wt% relative to the entire mixture of (1) to (3).

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