JP7702374B2 - Resin manufacturing method and insulating structure manufacturing method - Google Patents

Description

The present invention relates to a resin manufacturing method and an insulating structure manufacturing method.

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 conductor inside the coil from leaking to the outside.

As an example of the above-mentioned insulation structure, a structure is known in which an insulating tape containing mica or the like is wrapped around the outer circumference of a conductor, and the space inside the insulating tape is impregnated with a resin containing a filler made of metal oxide or the like. The filler functions to suppress the development of electrical trees that occur inside the insulating tape and improve the insulation performance.

US Patent Application Publication No. 2013/0131218 JP 2006-246599 A

Conventionally, the electric field strength of insulation for rotating electrical appliances is about 3 kV/mm. If this could be increased, the space factor of the windings could be increased, leading to an improvement in the output of the individual unit.
In addition, the effect of the filler in suppressing the propagation of electrical trees as described above depends greatly on the dispersibility of the filler. That is, if the dispersibility of the filler is low, the filler aggregates in the insulating structure, and the area where the electrical tree is likely to propagate (area containing only resin) increases, so that the effect of suppressing the propagation of electrical trees is reduced.

In addition, the viscosity of the resin containing the filler has a significant effect on the productivity of the insulating structure. For example, if the viscosity of the resin increases unintentionally, it becomes difficult to impregnate the resin into insulating tape, etc.

As mentioned above, in order to efficiently manufacture high-performance insulating structures, it is important to produce resins with high filler dispersion and viscosity stability.

Therefore, the present invention aims to provide a resin manufacturing method and an insulating structure manufacturing method that enable the efficient manufacture of high-performance insulating structures that are highly effective in suppressing the progression of electrical trees.

One aspect of the present invention is a resin manufacturing method for producing a resin to be impregnated into an insulating structure formed on the outer periphery of a conductor, the method including 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 the reactive diluent has been mixed therewith and shear mixing to generate a mixture, and a hardener mixing step of mixing an acid anhydride hardener with the mixture after the epoxy resin mixing step.

FIG. 1 is a cross-sectional view showing the configuration of a rotating electric machine according to an embodiment. FIG. 2 is a perspective view showing the configuration of an insulated coil according to the embodiment. FIG. 3 is a cross-sectional view showing the configuration of an insulated coil according to an embodiment. FIG. 4 is a cross-sectional view that illustrates a schematic configuration of a main insulating tape according to an embodiment. FIG. 5 is a cross-sectional view that illustrates a schematic internal structure of a main insulating portion according to the embodiment. FIG. 6 is a diagram showing the effects according to the embodiment. FIG. 7 is a cross-sectional view that illustrates the effect of the nanofiller according to the embodiment. FIG. 8 is a flowchart showing the steps of a method for manufacturing an insulation structure of an insulated coil according to the embodiment. FIG. 9 is a diagram showing the state of an impregnation apparatus used in a manufacturing method of an insulating structure according to an embodiment at a first half stage. FIG. 10 is a diagram showing the state of an impregnation apparatus used in a manufacturing method of an insulating structure according to an embodiment at a latter stage. FIG. 11 is a flowchart showing the steps of a method for producing a resin according to an embodiment. FIG. 12 is a diagram showing a test method for the electrical tree suppression test. FIG. 13 is a diagram for explaining the measurement results of the length of the electrical tree in the embodiment and the conventional example.

Below, an embodiment of the present invention will be described with reference to the drawings. In this specification, components according to the embodiment and explanations of the components may be described in multiple ways. The components and their explanations are merely examples and are not limited by the expressions in this specification. The components may also be identified by names different from those in this specification. Furthermore, the components may also be explained by expressions different from those in this specification.

<Configuration of Rotating Electric Machine>
FIG. 1 is a cross-sectional view showing the configuration of a rotating electrical machine 1 according to an embodiment.
The rotating electric machine 1 has a rotor 10 and a stator 20. The rotating electric machine 1 is a component of, for example, an electric motor, a generator, or the like.

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. The bearings 5 are fixed to bearing brackets 7 that are integral with a frame 6 that constitutes the outer shell of the rotating electric machine 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.

The stator 20 has a stator core 21 and an insulating coil 22. The stator core 21 is arranged radially outside the rotor core 12 with a gap between them. The insulating coil 22 is a member that is incorporated into the stator core 21 and generates a magnetic field that is essential for the rotating electric machine 1, and its outer periphery is provided with an insulating structure described below. The insulating coil 22 is assembled so as to penetrate through the stator core 21.

<Configuration of insulated coil>
Fig. 2 is a perspective view showing the configuration of the insulated coil 22 according to the embodiment. Fig. 3 is a cross-sectional view showing the configuration of the insulated coil 22 according to the embodiment.

The insulated 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 form the insulation structure of the insulated coil 22.

The laminated conductor 31 is composed of multiple laminated conductors 31A. The laminated conductor 31 according to this embodiment is composed of 14 bundled conductors 31A (7 layers, 2 rows). The configuration of the laminated conductor 31 is not limited to this, and should be designed appropriately according to the usage situation. The laminated conductor 31 may be composed of more than 14 conductors 31A, for example, or may be composed of only one laminated conductor 31A.

A 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 the turn insulation portion 33. A main insulation portion 35 is provided on the outside of the turn insulation portion 33. The main insulation portion 35 is formed by winding a main insulation tape 40 (tape-shaped member).

The main insulating tape 40 according to this embodiment is wound in a spiral shape using a half-wrap method. When the width of the main insulating tape 40 is W, the pitch of the spiral is W/2. That is, the main insulating tape 40 is wound so as to overlap half of the main insulating tape 40 wound in the previous turn. After the winding in the entire longitudinal direction of the laminated conductor 31 is completed, the main insulating tape 40 may be wound so as to overlap it further. This allows the main insulating tape 40 to be formed in a multi-layered structure. The more layers of the main insulating tape 40 are formed, the more the insulating performance can be improved. The number of turns of the main insulating tape 40 may be appropriately selected according to the required insulating performance, etc.

Figure 4 is a cross-sectional view showing a schematic configuration of the main insulating tape 40 according to the embodiment.

The main insulating tape 40 has a main insulating layer 41, a fiber reinforced layer 42, and a polymer layer 43.

The main insulating layer 41 is made of a non-conductive material and is the main part that realizes the insulating function of the main insulating tape 40. The fiber reinforced layer 42 is a part that supports the main insulating layer 41 and has the function of ensuring the strength of the main insulating tape 40 as a whole. The polymer layer 43 contains a bonding polymer and is a part that has the function of penetrating the fiber reinforced layer 42 and bonding the fiber reinforced layer 42 and the main insulating layer 41.

The main insulating layer 41 contains, as a main component, an inorganic substance such as mica, asbestos, or porcelain powder. The fiber-reinforced layer 42 contains, as a main component, for example, glass fiber or polyester fiber, and is usually woven into a mesh shape. The fiber-reinforced layer 42 is not limited to fibers, and may be made of nonwoven fabric or a polymer film such as polyester or polyimide. The polymer layer 43 contains, as a main component, for example, unsaturated polyester resin, epoxy resin, or polyimide resin.

The thickness of the main insulating layer 41 is, for example, about 100 μm. The thickness of the fiber-reinforced layer 42 is thinner than the main insulating layer 41, and is often, for example, about 30 μm or less. In FIG. 4, the polymer layer 43 is illustrated as a component of the main insulating tape 40, but since the polymer layer 43 penetrates into the fiber-reinforced layer 42, the thickness of the polymer layer 43 alone is almost nonexistent. Therefore, the main insulating layer 41 and the fiber-reinforced layer 42 are usually almost in contact with each other. The main insulating tape 40 is usually wound with the main insulating layer 41 facing the laminated conductor 31 to be insulated and the fiber-reinforced layer 42 on the outside, but the opposite is also possible.

<Internal structure of main insulation>
FIG. 5 is a cross-sectional view that shows a schematic internal structure of the main insulating portion 35 according to the embodiment.
5 shows a cross section along the longitudinal direction of the laminated conductor 31 (conductor 31A). Fig. 5 shows a case where the main insulating tape 40 is wound twice, and the main insulating part 35 includes a taping layer A formed by the first winding and a taping layer B formed by the second winding.

The main insulating section 35 has a main insulating layer 41 and an impregnated section 50. In each of the taping layers A and B, the main insulating layers 41 adjacent to each other in the longitudinal direction overlap each other by half their width. This is due to the winding method of the half-wrap method described above.

The impregnated portion 50 is a portion formed by the penetration of a resin containing nanofiller 55 into or around the polymer layer 43 that joins the main insulating layer 41 and the fiber-reinforced layer 42. In FIG. 5, the thickness of the main insulating layer 41 is shown thin and the lines representing the fiber-reinforced layer 42 are omitted in order to emphasize the polymer layer 43 that has been formed by penetration into or around the fiber-reinforced layer 42. As shown in FIG. 5, the periphery of the main insulating layer 41 is covered with the impregnated portion 50 (polymer layer 43) in which the nanofiller 55 is dispersed. The resin containing nanofiller 55 also penetrates into the inside of the main insulating layer 41, but this is not shown in FIG. 5.

FIG. 6 is a diagram showing the effects according to the embodiment.
The nanofiller 55 is a non-conductive nano-sized particle, for example, a particle containing a metal oxide. Specific examples of materials constituting the nanofiller 55 will be described later. It is important to select the particle size and filling rate so that the nanofiller 55 is uniformly dispersed in the resin without agglomeration and the interparticle distance is about 100 nm or less. The interparticle distance is particularly important, and it is desirable to set the interparticle distance based on the particle size and particle filling rate. As the basis for this, 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 to a certain extent (preferably 2 wt% or more), it has been experimentally confirmed by several tests that the progress of the electrical tree progressing 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 progressed electrical tree shape 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 branch-like shape toward the ground electrode.

Figure 7 is a cross-sectional view that shows the effect of the nanofiller 55 according to the embodiment.

Figure 7 shows the state in which an electrical tree T has occurred in the impregnated portion 50. The electrical tree T is an electrical degradation phenomenon caused by a voltage applied to the laminated conductor 31 and the stator 20. When the electrical tree T progresses and reaches the surface layer of the main insulation portion 35, insulation breakdown occurs, and the rotating electric machine 1 stops operating.

The nano-fillers 55 dispersed within the impregnated portion 50 have a propagation suppression effect of suppressing the linear propagation of the electrical tree T and slowing down the propagation speed of the electrical tree T. This can improve the insulation performance of the main insulation portion 35. Such a propagation suppression effect strongly depends on not only the content of the nano-fillers 55 but also on their dispersibility. The propagation suppression effect increases as the dispersibility (uniformity of dispersion) of the nano-fillers 55 within the impregnated portion 50 increases. Therefore, in order to improve the propagation suppression effect (insulation performance), it is important to use a resin with high dispersibility of the nano-fillers 55.

<Method of manufacturing the insulating structure>
Fig. 8 is a flowchart showing the steps of the method for manufacturing the insulating structure of the insulated coil 22 according to the embodiment. Fig. 9 is a diagram showing the state of an impregnation device 60 used in the method for manufacturing the insulating structure according to the embodiment in the first half of the process.

First, the main insulating tape 40 is wound around the laminated conductor 31 (see FIG. 2) to form the insulating coil 22 before resin impregnation (S101). Then, the insulating 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 placed in the impregnation device 60 (S103), and the inside of the impregnation device 60 is evacuated (S104).

As shown in FIG. 9, the impregnation device 60 has 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 placed in the treatment tank 64 placed in the airtight container 61. Then, in step S104, the airtight container 61 is evacuated. When evacuating, the supply valve 63A is closed, and the air in the airtight container 61 is sucked in by a suction device connected to the exhaust pipe 62. As a result, the inside of the insulating coil 22, the turn insulating portion 33, and the space in the main insulating tape 40 wound around it are all in a vacuum state.

After the vacuum is drawn as described above, the stator unit 90 in the treatment tank 64 is immersed in the resin 47 (S105), as shown in FIG. 9. 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.

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

FIG. 10 is a diagram showing the state of an impregnation apparatus 60 used in a manufacturing method of an insulating structure according to an embodiment at a later stage.
10, the pressurization is performed by opening a supply valve 63A and supplying pressurized gas 65 into the airtight container 61 from a supply pipe 63. 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 gas or dry air.

By pressurizing the airtight container 61 in this manner, the resin 47 containing the nanofiller 55 is impregnated into the turn insulation portion 33 of the insulated coil 22 and the main insulating tape 40.

Thereafter, the stator unit 90 is removed from the impregnation device 60 (S107), and the resin 47 impregnated inside the insulating coil 22 including the main insulating tape 40 is solidified (S108).
The method for solidifying the resin 47 is determined according to the properties of the epoxy resin used. For example, when a thermosetting epoxy resin is used, the stator unit 90 is placed in a drying oven at a predetermined temperature for a predetermined time, and the stator 20 is finally formed (see FIG. 1).

The stator 20 is then attached to the frame 6 that forms the outer shell. Depending on the specifications of the rotating electric machine 1, the insulated coil 22 may be assembled inside 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 insulated coil 22 is treated as the stator unit 90.

<Resin manufacturing method>
The following describes a method for manufacturing the resin 47 to be impregnated into the main insulating tape 40. As described above, in order to improve the effect of the nano-filler 55 in suppressing the progress of the electrical tree T (insulation performance of the main insulating portion 35), it is necessary to form an impregnated portion 50 in which the nano-filler 55 is dispersed with high dispersibility (uniformity) in the main insulating tape 40. In order to form such an impregnated portion 50, it is important to manufacture and use a resin 47 in which the nano-filler 55 is highly dispersible.

The resin 47 in this 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).

Epoxy resins include compounds that contain two or more three-membered rings consisting of two carbon atoms and one oxygen atom in one molecule and can be cured. Epoxy resins include, for example, bisphenol A type epoxy resins, alicyclic epoxy resins, bisphenol F type epoxy resins, biphenyl type epoxy resins, naphthalene type epoxy resins, novolac type epoxy resins, and phenol novolac type epoxy resins as main components. Epoxy resins may contain these compounds alone or in combination of two or more. In particular, it is preferable that the epoxy resin contains an alicyclic epoxy resin from the viewpoint of chemical affinity with the reactive diluent.

Nanofiller 55 includes non-conductive metal oxides and the like. Nanofiller 55 includes, 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, and the like as main components. Nanofiller 55 may include these compounds alone or in combination of two or more kinds.

The reactive diluent reacts with the epoxy resin to reduce the viscosity of the epoxy resin. The reactive diluent includes a compound that has a reactive group in the molecular skeleton and can become a part of the skeleton in the cured product of the thermosetting resin composition. The reactive diluent includes, 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. as the main component. The reactive diluent may include these compounds alone or in combination of two or more. In particular, when the epoxy resin includes an alicyclic epoxy resin, it is preferable that the reactive diluent includes butyl glycidyl ether.

The polymerization accelerator includes, for example, a compound that can accelerate the crosslinking reaction between an epoxy compound and an acid anhydride curing agent. The curing accelerator includes, for example, tertiary amines, phosphorus compounds, metal chelate compounds, ammonium ion compounds, imidazole compounds, etc. as main components. The curing accelerator may include these compounds alone or in combination of two or more kinds.

Acid anhydride curing agents include, for example, 4-methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, 4-methyltetrahydrophthalic anhydride, tetrabromophthalic anhydride, nadic anhydride, methylnadic anhydride, trimellitic anhydride, pyromellitic anhydride, methylhimic anhydride, etc. as main components. Acid anhydride curing agents may contain these compounds alone or in combination of two or more kinds.

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

11 is a flow chart showing the procedure of the method for producing the resin according to the embodiment. For example, first, 30 wt % of the nanofiller 55 and 70 wt % of the reactive diluent as a solvent are mixed together (S201).
Next, the nanofiller surface is chemically modified (chemical modification step: S202). For example, a hydrophobizing agent for the nanofiller surface is added to the mixture produced in step S201 to carry out a hydrophobizing reaction. For example, --OH (hydroxyl group) on the surface of the nanofiller 55 is removed to carry out a hydrophobizing treatment or the like for the surface of the nanofiller 55. For example, a silane coupling agent such as hexamethyldisilazane can be cited as an example of the hydrophobizing agent.
In this case, in order to promote and stabilize the chemical modification, stirring may be continued for a while after mixing, or the mixture may be allowed to stand for a while after mixing and stirring.
To further accelerate the reaction, the temperature may be increased.

This chemical modification process is performed to suppress the reactivity of the nanofiller 55 particle surface (improving the pot life) and to suppress the reactivity between the epoxy resin to be mixed later and the nanofiller 55, thereby suppressing the growth of electrical trees inside the resin. This chemical modification process is, for example, a particle surface modification process, and is performed to suppress the growth of electrical trees inside the resin by reducing the stress applied to the resin near the nanofiller by reducing the reactivity between the nanofiller 55 particle surface and the resin. By reducing the stress of the resin near the nanofiller, the future occurrence of microcracks is suppressed, and as a result, the occurrence of an uneven electric field is suppressed and the growth of electrical trees is also suppressed. Examples of this include a hydrophobic treatment that removes -OH groups present on the nanofiller surface, and a method of modifying the surface with methyl groups, ethyl groups, etc., which have low reactivity. For example, in this case, the degree of hydrophobicity is set to 24% or less, but from the viewpoint of the dispersibility of the nanofiller 55, 8 to 15% is preferable.

Next, in the shear mixing process of step S203, resin and polymerization accelerator are added so that, for example, the resin, reactive diluent and polymerization accelerator together amount to 90 wt % and the nanofiller 55 amount to 10 wt %, and then shear mixing is performed to obtain a mixture with a viscosity of less than 10 P (poise: dPa·s).
The shear mixing step is performed using an appropriate device capable of generating shear stress in the mixture, for example, a three-roll mill mixer, a planetary mixer, a Labo Plastomill (registered trademark) mixer, a Miracle KCK (registered trademark) mixer, etc. In the above explanation, the case where shear mixing is performed is described, but it is not limited to this as long as the nano filler 55 can be uniformly dispersed in the resin.

Next, the mixture produced by the shear mixing step (S203) is subjected to an evaluation of the dispersibility of the nanofiller 55 (dispersibility evaluation step: S204).
As a method for evaluating the dispersibility of the nanofiller 55, for example, there is a method for irradiating the mixture with a laser pointer.

In this case, the nanofillers 55 in the mixture scatter the light of the laser pointer (Tyndall phenomenon), so when the laser pointer is directed at the mixture, a light trail may appear in the mixture. For example, when red light having a wavelength of 635 nm to 690 nm is irradiated onto the mixture, if the nanofillers 55 are poorly dispersible and the particle size of the nanofiller 55 aggregates is larger than the wavelength, the trail of the irradiated light will appear clearly in the mixture.

In contrast, when the nanofiller 55 has high dispersibility and the particle size of the aggregate of the nanofiller 55 is smaller than the wavelength, the light trail has low luminous intensity and is barely visible.
Therefore, it can be evaluated that the lower the luminous intensity of the trajectory of the irradiated light appearing in the mixture, the higher the dispersibility of the nanofiller 55 in the mixture.

In the present embodiment, when red light is irradiated onto the mixture produced through steps S201 to S203, the light trail in the mixture is barely visible, and the luminosity is extremely low, resulting in a very high dispersibility of the nanofiller 55. When using a laser pointer, the area of the mixture moving to the hardener mixing step may be divided into a mesh or dice shape, and laser light may be irradiated onto all divided areas, so that it may be determined whether the mixture meets a predetermined dispersibility standard if the luminosity of the light trail appearing in the mixture for each divided unit is equal to or less than a threshold value. The luminosity may 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 be low in dispersibility and not meeting the predetermined standard is discarded (S207), and the process returns to step S201.
In this way, it is possible to prevent a mixture with uneven dispersibility from proceeding to the next step. If the quality of the upstream steps is good and unnecessary, steps S204 and S207 may be omitted. In the case of a manufacturing device in which the dispersibility of the mixture can be evaluated in units of separated regions and only the separated specific regions can proceed to the next step, only the regions determined to have good dispersibility may be allowed to proceed to the next step, step S205.

Although the method using a laser pointer is simple and convenient, it is also possible to use various particle size measuring devices that measure the particle size of the nanofiller 55 in the mixture based on the Brownian motion, etc.

If it is determined in the dispersibility evaluation process that the dispersibility meets the specified high standard (S204; high dispersibility), the process proceeds to the next hardener mixing process S205. In the hardener mixing process S205, an acid anhydride hardener is added to the mixture produced in the shear mixing process (S203), and the mixture is mixed and stirred.

Here, the acid anhydride hardener is mixed in the same amount as the epoxy resin used, in a chemically equivalent amount. This hardener mixing step is carried out so that the composition has a predetermined viscosity (for example, a viscosity that is practically appropriate for the resin 47 used for impregnation). Furthermore, the mixing in the hardener mixing step can be carried out using an appropriate device capable of high-speed mixing. For example, a disperser mixer, a concentric twin-shaft mixer, a planetary mixer, a bead mill mixer, etc. can be used.

Then, the mixture produced by the hardener mixing step (S205) is collected (S206). The collected mixture is used as the resin 47 for impregnation as described above.

By using the above-described manufacturing method, the surface of the nano-filler 55 is chemically modified, so that the nano-filler 55 is dispersed with high dispersibility, and a resin 47 in which stress is relaxed can be manufactured.
As a result, it is possible to improve the effect (insulation performance) of suppressing the progress of the electrical tree T by the nano-filler 55. In addition, due to the high dispersibility of the nano-filler 55, it is possible to stabilize the viscosity of the resin 47 for a long period of time, and it is possible to improve the usable life of the resin 47.

In the procedure of FIG. 11, the surface of the nanofiller is chemically modified after mixing the reactive diluent with the nanofiller. However, the nanofiller alone may be chemically modified and then mixed with the reactive diluent. For example, the nanofiller alone may be chemically modified by high-energy ion implantation (plasma irradiation with argon gas, etc.), or may be treated with fluorine plasma, treated with a fluorine compound, or treated with silane coupling.

<Evaluation of Electrical Tree Suppression Effect>
An example of comparison of the electrical tree suppression effect of the resin-impregnated insulating structure manufactured by the manufacturing method of each of the above-mentioned embodiment and the conventional example will be shown below.

FIG. 12 is a diagram showing a test method for the electrical tree suppression test.
First, the resin 47 according to the embodiment was cured with the needle-shaped electrode 111 embedded therein, and a test piece 101 was prepared in which the portion facing the electrode 111 served as a ground electrode.

The test piece 101 is immersed in silicone oil 102.

A high voltage (15 kVp, 18 kVp, 21 kVp) was applied from the voltage generator 112 to each electrode 111, and the length of the electrical treeing in the test piece 101 was measured with a microscope. Next, a voltage was applied to a test piece 101 of a similar structure made of resin 47 using a conventional manufacturing method, and the electrical treeing lengths were compared.

FIG. 13 is a diagram for explaining the measurement results of the length of the electrical tree in 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, the length of the electrical tree was 0.5 mm when the applied voltage was 15 kVp.

At an applied voltage of 18 kVp, the length of the electrical tree was 0.3 mm, and at an applied voltage of 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, the length of the electrical tree was 3.2 mm when the applied voltage was 15 kVp.

At an applied voltage of 18 kVp, the length of the electrical tree was 4.2 mm, and at an applied voltage of 21 kVp, the electrical tree extended to the vicinity of the ground electrode and was saturated.
As described above, it is clear that the present embodiment has a greater effect of suppressing the progress of electrical trees than the conventional example.

As described above, according to this embodiment, it is possible to manufacture a resin 47 having high dispersibility of the nanofiller 55 and high viscosity stability. This makes it possible to efficiently manufacture a high-performance insulation structure that can more reliably suppress the progression of electrical trees.

The above-described embodiment of the present invention does not limit the scope of the invention, but is merely an example within the scope of the invention. An embodiment of the present invention may be one in which, for example, at least a portion of the specific uses, structures, shapes, actions, and effects of the above-described embodiment are modified, omitted, or added without departing from the gist of the invention.

1...rotating electric machine, 5...bearing, 6...frame, 7...bearing bracket, 10...rotor, 11...rotor shaft, 12...rotor core, 20...stator, 21...stator core, 22...insulating coil, 31...laminated conductor (conductor), 31A...conductor, 33...turn insulation section, 35...main insulation section, 40...main insulation tape (tape-shaped member), 41...main insulation layer, 42...fiber-reinforced layer, 43...polymer layer, 47...resin, 50...impregnated section, 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...ground electrode, T...electrical tree.

Claims (6)

A method for manufacturing a resin to be impregnated into an insulating structure formed on an outer periphery of a conductor, comprising the steps of:
A chemical modification step of chemically modifying the surface of the nanofiller alone ;
mixing the nanofiller after the chemical modification step with a reactive diluent;
an epoxy resin mixing step of adding an epoxy resin and a polymerization accelerator to the nanofiller after mixing the reactive diluent and shear-mixing the mixture to form an epoxy resin mixture;
a curing agent mixing step of mixing an acid anhydride curing agent into the mixture obtained after the epoxy resin mixing step;
A method for producing a resin comprising the steps of: The chemical modification step is any one of high-energy ion implantation, fluorine plasma treatment, fluorine compound treatment, and silane coupling treatment.
The method for producing a resin according to claim 1. The chemical modification step is to hydrophobize the surface of the nanofiller,
The hydrophobization is the removal of hydroxyl groups on the surface of the nanofiller.
The method for producing a resin according to claim 2. The epoxy resin includes an alicyclic epoxy resin.
The method for producing a resin according to claim 1. Including butyl glycidyl ether as the reactive diluent;
The method for producing a resin according to claim 1 . 1. A method for manufacturing an insulating structure formed on the periphery of a conductor, comprising the steps of:
A resin manufacturing process for manufacturing a resin containing nanofillers;
impregnating a non-conductive tape-like member wound around an outer periphery of the conductor with the resin;
Including,
The resin manufacturing process includes:
A chemical modification step of chemically modifying the surface of the nanofiller alone ;
mixing the nanofiller after the chemical modification step with a reactive diluent;
an epoxy resin mixing step of adding an epoxy resin and a polymerization accelerator to the nanofiller after mixing the reactive diluent and shear-mixing the mixture to form an epoxy resin mixture;
a curing agent mixing step of mixing an acid anhydride curing agent into the mixture obtained after the epoxy resin mixing step;
Including,
Insulation structure manufacturing method.

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