Insulating tape, insulating coil, rotating machine, and insulating coil manufacturing method

Abstract

An insulating tape (100) is impregnated with a liquid resin containing at least one of a bisphenol A-type epoxy compound having a repeating number of zero and a bisphenol F-type epoxy compound having a repeating number of zero. A microcapsule (130) includes an outer shell body and an inclusion material having a property of promoting curing of the liquid resin. A binder layer (120) is composed of a crystalline epoxy resin having a molecular structure in which two phenyl groups are linked by a single bond, a molecular structure in which two phenyl groups are linked by an ether bond, or a molecular structure in which two phenyl groups are linked by a methylene group.

Description

Insulating tape, insulating coil, rotating machine, and method for manufacturing insulating coil

[0001] The present disclosure relates to an insulating tape, an insulating coil, a rotating machine, and a method for manufacturing an insulating coil.

[0002] As disclosed in Patent Document 1, an insulating tape containing laminated mica is known. This insulating tape is used after undergoing an impregnation process in which the laminated mica is impregnated with a liquid resin (hereinafter referred to as liquid resin). The laminated mica is obtained by crushing mica into scaly pulverized material, which is then molded into a sheet.

[0003] In the impregnation process, liquid resin prepared in advance in a tank is used to impregnate the insulating tape. After impregnation, the liquid resin remaining in the tank is used to impregnate another insulating tape. In this way, the liquid resin in the tank is reused for repeated impregnation processes.

[0004] Therefore, in order to enable appropriate repeated impregnation, it is desirable to improve the pot life of the liquid resin in the tank, that is, to suppress the increase in viscosity of the liquid resin in the tank over time.

[0005] Therefore, in the insulating tape disclosed in Patent Document 1, a curing catalyst that promotes the curing of the liquid resin is supported in the form of a microcapsule that is encapsulated in an outer shell. Because the curing catalyst is encapsulated in the outer shell, the curing catalyst is prevented from leaking into the liquid resin in the tank during impregnation with the liquid resin. As a result, the viscosity of the liquid resin in the tank is prevented from increasing over time.

[0006] Japanese Unexamined Patent Publication No. 64-85552

[0007] Patent Document 1 does not consider at all the compatibility between the binder for supporting the microcapsules on the mica aggregate and the liquid resin. If the binder and the liquid resin are not sufficiently compatible, there is a concern that voids, voids, and other structural defects may remain at the interface between the cured liquid resin and the re-cured binder after the liquid resin is cured.

[0008] The presence of structural defects can cause a decrease in the volume resistivity of insulating tape impregnated with a liquid resin, and ultimately a decrease in the breakdown voltage. Therefore, it is desirable to improve the volume resistivity by suppressing the formation of structural defects.

[0009] An object of the present disclosure is to provide a technology that can suppress the viscosity increase over time of the reused liquid resin even when the liquid resin for impregnation is reused, and can achieve electrical insulation with high volume resistivity.

[0010] The insulating tape according to the present disclosure is impregnated with a liquid resin. The liquid resin contains at least one of a bisphenol A epoxy compound with a repeating number of zero and a bisphenol F epoxy compound with a repeating number of zero. The insulating tape according to the present disclosure comprises a tape body layer, a binder layer, and a plurality of microcapsules. The tape body layer has a structure that allows it to be impregnated with the liquid resin. The binder layer is laminated on the tape body layer in the thickness direction of the insulating tape and is composed of a cured product of the binder that is attached to the tape body layer. The plurality of microcapsules are dispersed throughout the structure of the binder layer. The microcapsules have an outer shell that begins to melt at a temperature higher than the temperature at which the cured product of the binder begins to melt, and an encapsulated substance encapsulated in the outer shell. The encapsulated substance has the property of accelerating the curing of the liquid resin. The cured product of the binder is composed of a crystalline epoxy resin. The crystalline epoxy resin includes a molecular structure in which two phenyl groups are connected by a single bond, a molecular structure in which two phenyl groups are connected by an ether bond, or a molecular structure in which two phenyl groups are connected by a methylene group.

[0011] In the insulating tape according to the present disclosure, an encapsulated substance having properties that promote the hardening of the liquid resin is encapsulated in the outer shell. Therefore, even when the liquid resin used for impregnation is reused, the encapsulated substance is prevented from leaking into the reused liquid resin. Therefore, the viscosity of the reused liquid resin can be suppressed from increasing over time.

[0012] Furthermore, the crystalline epoxy resin having the above molecular structure has a molecular structure similar to that of the liquid resin impregnated into the insulating tape according to the present disclosure, and therefore has excellent compatibility with the liquid resin. Therefore, structural defects are less likely to remain after the impregnated liquid resin hardens. Therefore, the insulating tape according to the present disclosure can achieve electrical insulation with a high volume resistivity.

[0013] 6 is a cross-sectional view taken along line VII-VII in FIG. 6; and FIG. 7 is a perspective view showing an enlarged view of a main part of a stator core of a rotating machine according to the third embodiment.

[0014] An insulating tape according to an embodiment, an insulated coil including the insulating tape, and a rotating machine including the insulated coil will be described below with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals.

[0015] [Embodiment 1] Fig. 1 shows an insulating tape 100 according to this embodiment. This insulating tape 100 is formed in a long strip shape and is used by being wrapped around a conductor (not shown) (hereinafter referred to as the target conductor). Fig. 1 also shows a cross section of the insulating tape 100 perpendicular to the length direction.

[0016] Furthermore, after or before being wrapped around the target conductor, the insulating tape 100 is impregnated with a liquid resin. After the impregnated liquid resin hardens, the insulating tape 100 serves to electrically insulate the target conductor from external components.

[0017] First, the liquid resin for impregnation will be described. The liquid resin used contains at least one of a bisphenol A type epoxy compound with a repeat number of zero and a bisphenol F type epoxy compound with a repeat number of zero. Since epoxy compounds are thermosetting, the liquid resin also has thermosetting properties.

[0018] The bisphenol A epoxy compound is represented by the following formula (a1): In the following formula (a1), m represents the number of repeating units of the bisphenol A epoxy compound.

[0019]

[0020] A bisphenol A epoxy compound having a repeat number m of zero that can be used as a liquid resin according to the present embodiment is represented by the following formula (a2). The structure obtained by removing hydrogen atoms from both ends of bisphenol A is referred to as a "bisphenol A skeleton." As shown in the following formula (a2), a bisphenol A epoxy compound having a repeat number m of zero has a structure in which epoxy groups are directly bonded to both ends of the bisphenol A skeleton.

[0021]

[0022] On the other hand, the bisphenol F type epoxy compound is represented by the following formula (b1): m in the following formula (b1) represents the number of repetitions of the bisphenol F type epoxy compound.

[0023]

[0024] A bisphenol F epoxy compound having a repeat number m of zero that can be used as a liquid resin according to the present embodiment is represented by the following formula (b2). The structure obtained by removing hydrogen atoms from both ends of bisphenol F is called a "bisphenol F skeleton." As shown in the following formula (b2), a bisphenol F epoxy compound having a repeat number m of zero has a structure in which epoxy groups are directly bonded to both ends of the bisphenol F skeleton.

[0025]

[0026] Both the bisphenol A epoxy compound having a repeat number m of zero and the bisphenol F epoxy compound having a repeat number m of zero are extracted by distillation, have low impurity contents, and exhibit excellent voltage resistance after curing. Furthermore, compared with undistilled epoxy compounds, these epoxy compounds extracted by distillation have smaller molecular weights and narrower molecular weight distributions, resulting in low viscosity and excellent impregnation into insulating tape 100.

[0027] A bisphenol A epoxy compound having a repeat number m of zero and a bisphenol F epoxy compound having a repeat number m of zero may be used in combination. In this case, the bisphenol A epoxy compound having a repeat number m of zero and the bisphenol F epoxy compound having a repeat number m of zero are hereinafter referred to as a "combined product."

[0028] From the viewpoint of suppressing a decrease in viscosity of the liquid resin due to crystallization during storage, it is preferable to use a mixture of a bisphenol A type epoxy compound in which the repeat number m is zero or a bisphenol F type epoxy compound in which the repeat number m is zero, rather than using either one alone.

[0029] The mass ratio MA / MB in the combination of the mass MA of the bisphenol A epoxy compound in which the repeat number m is zero and the mass MB of the bisphenol F epoxy compound in which the repeat number m is zero is preferably 0.3 or more and 4.5 or less.

[0030] By setting the mass ratio MA / MB to 0.3 or more, it is possible to ensure particularly good mechanical strength of the cured combination, and by setting the mass ratio MA / MB to 4.5 or less, it is possible to realize a combination that is particularly excellent in terms of impregnation into insulating tape 100.

[0031] The proportion of the bisphenol A epoxy compound having a repeating number of zero, the bisphenol F epoxy compound having a repeating number of zero, or a combination thereof (hereinafter collectively referred to as epoxy compound) in the liquid resin is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0032] Furthermore, the liquid resin preferably does not contain a substance such as a catalyst or a curing agent that has the property of curing the epoxy compound (hereinafter collectively referred to as a curable substance). Typical examples of the curable substance include acid anhydrides. The liquid resin may also consist solely of the epoxy compound.

[0033] However, the liquid resin may contain a substance other than an epoxy compound (excluding curable substances), typically an epoxy compound containing three or more epoxy groups in the molecule (hereinafter referred to as a second epoxy compound).

[0034] For example, when the combination product is used in combination with a second epoxy compound, where MC is the mass of the second epoxy compound in the liquid resin, the mass ratio (MA+MB) / MC is preferably 2 or more and 5 or less, thereby further improving the heat resistance of the cured product of the liquid resin.

[0035] Next, the configuration of the insulating tape 100 impregnated with the liquid resin described above will be described.

[0036] 1, the insulating tape 100 includes a tape body layer 110, a reinforcing layer 140 that reinforces the tape body layer 110, and a binder layer 120 that is interposed between the tape body layer 110 and the reinforcing layer 140. The tape body layer 110, the binder layer 120, and the reinforcing layer 140 are all formed in the shape of a long strip. The tape body layer 110, the binder layer 120, and the reinforcing layer 140 are layered in this order in the thickness direction of the insulating tape 100.

[0037] The tape body layer 110 has a structure that can be impregnated with the liquid resin described above. Specifically, the tape body layer 110 is composed of a mica structure that is an aggregate of scale-like mica (hereinafter referred to as scale-like mica). The liquid resin can be impregnated into the minute gaps between adjacent scale-like mica particles that make up the mica structure.

[0038] The scaly mica is a layered silicate mineral processed into a scaly shape, and may be a hard mica such as muscovite, or a soft mica such as phlogopite. As an example, the mica structure is an aggregated mica formed by shearing the scaly mica.

[0039] The reinforcing layer 140 is made of a material having a higher tensile strength than the tape body layer 110, such as glass cloth or a resin film. From the viewpoint of increasing the strength of the insulating tape 100, the reinforcing layer 140 is preferably made of glass cloth.

[0040] The binder layer 120 serves to bond the reinforcing layer 140 to the tape body layer 110. The binder layer 120 is composed of a cured product of a binder that is attached to the tape body layer 110 and the reinforcing layer 140.

[0041] The cured binder is composed of a crystalline epoxy resin containing a molecular structure in which two phenyl groups are linked by a single bond, a molecular structure in which two phenyl groups are linked by an ether bond, or a molecular structure in which two phenyl groups are linked by a methylene group, and does not contain a curable substance. Note that the single bond here means a direct covalent bond between a carbon atom constituting one of the two phenyl groups and a carbon atom constituting the other, without any other atoms passing through.

[0042] Here, "crystalline" means that the structure of a solid crystalline epoxy resin has portions in which molecular chains are regularly arranged. The regularity of the molecular chain arrangement in the structure of a crystalline epoxy resin is higher than the regularity of the molecular chain arrangement in a cured product obtained by curing the above-mentioned liquid resin. A crystalline epoxy resin is solid at room temperature, specifically 25°C, and has a melting point. That is, when a crystalline epoxy resin is subjected to differential scanning calorimetry (DSC), the endothermic peak temperature based on the melting point can be confirmed from the measurement results.

[0043] The preferred melting point of the crystalline epoxy resin will be described in embodiment 2. As will be described later, the viscosity of the crystalline epoxy resin when molten is preferably equal to the viscosity of the liquid resin described above, and more preferably lower than the viscosity of the liquid resin described above.

[0044] Specifically, the above-mentioned crystalline epoxy resin contains a compound represented by the following formula (c):

[0045]

[0046] In the above formula (c), R ｂ１ , R ｂ２ , R ｂ３ , R ｂ４ , R ｂ５ , R ｂ６ , R ｂ７ , R ｂ８ are each independently a hydrogen atom (H) or a methyl group (CH ３ ), and —Y— represents a single bond, an ether bond (—O—), or a bond via a methylene group (—CH ２ -). The single bond referred to here means a direct covalent bond between a carbon atom constituting one of a pair of adjacent benzene rings and a carbon atom constituting the other of the pair of adjacent benzene rings in the compound represented by the above formula (c), without any other atom being involved. In the above formula (c), the repeat number n is preferably 1 or more. When the repeat number n is 2 or more and the compound represented by the above formula (c) contains multiple pairs of adjacent benzene rings (hereinafter simply referred to as "pairs"), -Y- is independently a single bond (-), an ether bond (-O-), or a bond via a methylene group (-CH ２ -), and R ｂ３ , R ｂ４ , R ｂ５ , R ｂ６ is independently a hydrogen atom (H) or a methyl group (CH ３ ) shall represent the

[0047] The crystalline epoxy resin containing the molecular structure represented by formula (c) above has a similar molecular structure to the liquid resin impregnated into insulating tape 100 according to this embodiment. Therefore, the crystalline epoxy resin is fully compatible with the liquid resin when melted by heating.

[0048] Therefore, after the impregnated liquid resin has hardened, there are less likely to be any voids or other structural defects at the interface between the hardened liquid resin and the re-hardened crystalline epoxy resin, and the liquid resin and the crystalline epoxy resin are sufficiently compatible to form a homogeneous and dense structure. Therefore, the insulating tape 100 according to this embodiment can achieve electrical insulation with a high volume resistivity.

[0049] 1 , a plurality of microcapsules 130 are dispersed in the structure of the binder layer 120 described above. That is, the binder layer 120 also serves to support the plurality of microcapsules 130 on the insulating tape 100.

[0050] 2 shows a cross section of each microcapsule 130. The microcapsule 130 has a hollow shell 131 that forms the outer surface of the microcapsule 130, and an encapsulated substance 132 that is encapsulated in the shell 131.

[0051] Shell 131 is made of a material that is less likely to melt when heated than the cured product of the binder that constitutes binder layer 120. In other words, under the same pressure, shell 131 begins to melt at a temperature higher than the temperature at which the cured product of the binder that constitutes binder layer 120 begins to melt. When insulating tape 100 is impregnated with liquid resin, shell 131 maintains a state in which it retains encapsulated substance 132, and melts when heated after insulating tape 100 has been impregnated with the liquid resin.

[0052] It is preferable that outer shell 131 be made of a material that is more inactive to the hardening reaction of the liquid resin than encapsulated substance 132. Specifically, it is preferable that outer shell 131 be made of a resin that does not contain a hardenable substance.

[0053] The encapsulated substance 132 has catalytic properties that accelerate the hardening of the liquid resin. After the liquid resin is impregnated into the insulating tape 100, when the outer shell 131 melts and collapses, the encapsulated substance 132 becomes compatible with the impregnated liquid resin. At this time, the encapsulated substance 132 plays a role in accelerating the hardening of the liquid resin.

[0054] Specifically, the encapsulation substance 132 preferably contains a compound represented by the following formula (d): ａ１ , R ａ２ are each independently an amino group (NH ２ ) or a hydroxy group (OH), and —X— represents a single bond, an ether bond (—O—), or a bond via a methylene group (—CH ２The single bond herein means a direct covalent bond between a carbon atom constituting one of a pair of adjacent benzene rings and a carbon atom constituting the other of the pair of adjacent benzene rings, without any other atom passing through.

[0055]

[0056] Encapsulated substance 132 containing a compound having the chemical structure shown in formula (d) above has particularly excellent compatibility with the liquid resin impregnated into insulating tape 100 according to this embodiment. Furthermore, encapsulated substance 132 containing such a compound can form a cured liquid resin with high mechanical strength.

[0057] In addition, the group R in the above formula (d) ａ１ and group R ａ２ and at least one of them is an amino group (NH ２ ), the compound represented by the formula (d) above is a primary amine. A primary amine other than the primary amine may be contained in the encapsulation substance 132. However, when the group R ａ１ and group R ａ２ and may both be hydroxy groups (OH).

[0058] In addition, the encapsulated substance 132 may contain at least one selected from an imidazole group, a primary amine, a secondary amine, and a tertiary amine, either separately from the compound represented by formula (d) above or in combination with the compound represented by formula (d) above.

[0059] The encapsulated substance 132 having such a configuration also has particularly excellent compatibility with the liquid resin impregnated into the insulating tape 100 according to the present embodiment. Furthermore, the encapsulated substance 132 having such a configuration also makes it possible to form a cured liquid resin having high mechanical strength.

[0060] Furthermore, the encapsulated substance 132 described above may further contain triphenylphosphine-triphenylborane, boron trifluoride monoethylamine, boron trifluoride piperidine, boron trifluoride aniline, boron trichloride N,N-dimethyloctylamine complex, or the like as a hardening adjuster for adjusting the hardening speed of the liquid resin.

[0061] A method for manufacturing the insulating tape 100 will now be described with reference to FIG.

[0062] First, the tape body layer 110 is prepared, which has a structure that can be impregnated with a liquid resin. As described above, the tape body layer 110 can be made of aggregated mica. Aggregated mica is obtained by shearing flake mica.

[0063] Meanwhile, a solution of the binder that will form the binder layer 120 is prepared by dispersing a plurality of microcapsules 130 in the solution (step S11). As an example, the microcapsules 130 may be manufactured by Asahi Kasei Corporation under the trade name NOVACURE HX3722.

[0064] Next, the binder solution in which the microcapsules 130 are dispersed is applied to the outer surface of the tape body layer 110 (step S12). For application, a roll coater method, a spray method, or the like can be used.

[0065] Next, the reinforcing layer 140 is attached to the tape body layer 110 (step S13). Specifically, the reinforcing layer 140 is laminated on the layer of binder solution applied in step S12, and the laminated reinforcing layer 140 is pressure-bonded to the tape body layer 110 while being heated.

[0066] The layer of the binder solution described above is hardened to form the binder layer 120 shown in Fig. 1. In the structure of the binder layer 120, the plurality of microcapsules 130 dispersed in step S11 are scattered.

[0067] After step S13, a binder solution in which a plurality of microcapsules 130 are dispersed may be further applied to the outer surface of the reinforcing layer 140. For application, a roll coater method, a spray method, or the like may be used.

[0068] The insulating tape 100 obtained through the above steps is used in the state where it is wrapped around a target conductor and impregnated with liquid resin, as described above.

[0069] Second Embodiment Hereinafter, as an example of the use of the insulating tape 100 according to the first embodiment described above, a configuration in which the target conductor is a coil conductor will be described.

[0070] As shown in FIG. 4, an insulated coil 300 according to this embodiment includes an impregnated tape 200 and a coil conductor 310 around which the impregnated tape 200 is wound.

[0071] The coil conductor 310 is made up of a bundle of multiple metal wires, each covered with an insulating material.

[0072] The impregnated tape 200 comprises the insulating tape 100 described above and a cured product of the liquid resin impregnated into the insulating tape 100. In other words, the impregnated tape 200 is obtained by impregnating the insulating tape 100 described above with a liquid resin and then curing the impregnated liquid resin.

[0073] A method for manufacturing the insulated coil 300 will now be described with reference to FIG.

[0074] First, the insulating tape 100 is wrapped around the outer surface of the coil conductor 310 multiple times (step S21). The wrapping is performed under the condition that a part of the insulating tape 100 in the width direction overlaps with the insulating tape 100 already wrapped around the coil conductor 310.

[0075] Step S21 is an example of an insulating tape winding step according to the present disclosure. Hereinafter, the coil conductor 310 wound with insulating tape 100 obtained in step S21 will be referred to as a “first intermediate product.”

[0076] A protective tape may be further wrapped around the outer surface of the insulating tape 100 in the first intermediate product to protect the insulating tape 100. As the protective tape, a glass tape, a resin tape, or the like may be used.

[0077] Next, the first intermediate product is dried in a reduced pressure environment below atmospheric pressure, and then the insulating tape 100 in the first intermediate product is impregnated with the liquid resin described above (step S22). This step S22 is an example of the impregnation step according to the present disclosure.

[0078] The impregnation of the first intermediate product with the liquid resin is carried out in an impregnation tank in which the liquid resin is stored in advance, and is preferably carried out in a reduced pressure environment in which the pressure is reduced to a pressure lower than atmospheric pressure.

[0079] The liquid resin to be impregnated is preheated to a temperature above the melting point at which the crystalline epoxy resin constituting the binder layer 120 of the insulating tape 100 begins to melt (hereinafter referred to as the crystalline epoxy resin melting temperature).

[0080] The melting point of the crystalline epoxy resin is preferably 50° C. or higher and 150° C. or lower. Examples of crystalline epoxy resins having a melting point within this temperature range include "Product Name: YSLV-80XY" manufactured by Nippon Steel Chemical & Material Co., Ltd. and "Product Name: jER YX4000" manufactured by Mitsubishi Chemical Corporation.

[0081] If the melting point of the crystalline epoxy resin is 50°C or higher, the winding in step S21 can be performed in a high-temperature environment. That is, if the temperature of the insulating tape 100 when wound around the coil conductor 310 is less than 50°C, softening of the binder layer 120 and, consequently, separation of the microcapsules 130 from the binder layer 120 can be avoided.

[0082] Furthermore, if the melting point of the crystalline epoxy resin is 150°C or less, it is sufficient to heat the liquid resin to be impregnated in step S22 to a maximum of about 150°C, which allows for efficient heating of the liquid resin and therefore efficient production of the insulated coil 300.

[0083] Furthermore, by heating the liquid resin to the melting temperature of the crystalline epoxy resin, the liquid resin can be maintained in a low viscosity state due to heating, which allows the insulating tape 100, particularly the tape body layer 110, to be impregnated with the liquid compatible material containing the liquid resin to the very corners of the structure of the mica structure, thereby contributing to a densification of the structure of the impregnated tape 200 and an improvement in the breakdown voltage.

[0084] Furthermore, since the liquid resin is heated to the melting temperature of the crystalline epoxy resin, when the liquid resin is impregnated into the insulating tape 100, the crystalline epoxy resin that constitutes the binder layer 120 of the insulating tape 100 melts and becomes compatible with the impregnated liquid resin.

[0085] As mentioned above, the crystalline epoxy resin has a molecular structure similar to that of the liquid resin because it contains the molecular structure represented by the above formula (c), and therefore the melt of the crystalline epoxy resin has good compatibility with the liquid resin.

[0086] Therefore, after the impregnated liquid resin hardens, voids and other structural defects are unlikely to remain at the interface between the hardened liquid resin and the re-hardened crystalline epoxy resin. The liquid resin and the crystalline epoxy resin are sufficiently compatible to form a homogeneous and dense structure. Therefore, the insulating tape 100 according to this embodiment can achieve electrical insulation with a high volume resistivity.

[0087] The lower the viscosity of the crystalline epoxy resin when melted, the more preferable. The lower the viscosity of the crystalline epoxy resin when melted, the lower the viscosity of the liquid compatible material in which the crystalline epoxy resin and liquid resin are compatible. Reducing the viscosity of the liquid compatible material allows the liquid compatible material to be thoroughly impregnated into the structure of the insulating tape 100, which in turn contributes to a densification of the structure of the impregnated tape 200 and an improvement in the breakdown voltage.

[0088] Furthermore, it is preferable that the viscosity of the crystalline epoxy resin when melted is lower than the viscosity of the liquid resin when it is impregnated. In this case, the crystalline epoxy resin can play a role in lowering the viscosity of the liquid compatible material below the viscosity of the liquid resin.

[0089] Specifically, the crystalline epoxy resin preferably has a melting point of 90° C. or less and a viscosity at 90° C. of 1.0 Pa·sec or less.

[0090] Hereinafter, the insulating tape 100 impregnated with the liquid resin, which is obtained in step S22 and wound around the coil conductor 310, will be referred to as a "second intermediate product."

[0091] Next, after the liquid resin has been impregnated, the second intermediate product is removed from the impregnation tank (step S23). Thereafter, the shape of the coil conductor 310 in the second intermediate product may be adjusted as necessary.

[0092] The liquid resin remaining in the tank is used to impregnate the next insulating tape 100. In this way, the liquid resin in the tank is reused for repeated impregnation. Therefore, to enable appropriate repeated impregnation, it is desirable to improve the pot life of the liquid resin in the tank, that is, to suppress the viscosity of the liquid resin in the tank from increasing over time.

[0093] In this regard, in insulating tape 100 constituting the second intermediate product, encapsulated substance 132 having the property of accelerating the hardening of the liquid resin is encapsulated in outer shell 131. And, outer shell 131 maintains a state in which encapsulated substance 132 is held therein at the time of step S23.

[0094] Therefore, even when the liquid resin for impregnation is reused in the tank, the encapsulated substance 132 is prevented from leaking into the reused liquid resin, and the viscosity of the reused liquid resin can be prevented from increasing over time.

[0095] As described above, the liquid resin prepared in advance in the tank preferably does not contain an acid anhydride or other curable substances, which further improves the pot life of the liquid resin reused in the tank.

[0096] Next, the insulating tape 100 impregnated with the liquid resin in the second intermediate product removed from the tank is heated (step S24). This step S24 is an example of the heating step according to the present disclosure.

[0097] The heating in step S24 is preferably performed at a temperature of 120° C. to 180° C. for a period of 4 hours to 28 hours, for example. The heating in step S24 is also preferably performed in a pressurized environment where the pressure is higher than atmospheric pressure.

[0098] Heating promotes melting of the outer shells 131 of the microcapsules 130 in the insulating tape 100. This causes the outer shells 131 to collapse, and the encapsulated substance 132 contained in the outer shells 131 comes into contact with the liquid resin impregnated in the insulating tape 100. The encapsulated substance 132 then becomes compatible with the liquid resin impregnated in the insulating tape 100, promoting the hardening of the liquid resin.

[0099] Therefore, in step S24, the liquid resin can be quickly cured, and the liquid resin is less likely to leak from the insulating tape 100. Suppressing the leakage of the liquid resin from the insulating tape 100 suppresses the formation of voids, and ultimately contributes to improving the breakdown voltage of the impregnated tape 200.

[0100] When the liquid resin impregnated in the insulating tape 100 has completely hardened, the insulated coil 300 according to this embodiment is completed.

[0101] The encapsulated substance 132 described in the first embodiment has a molecular structure similar to that of the liquid resin, and is therefore particularly compatible with the liquid resin. Therefore, by using the encapsulated substance 132 according to the first embodiment, a cured liquid resin with a homogeneous structure and high mechanical strength is formed.

[0102] Third Embodiment A turbine generator will now be described as an example of an application of the insulated coil 300 according to the second embodiment described above.

[0103] As shown in Figures 6 and 7, the turbine generator 400 of this embodiment comprises a rotating rotor core 401, a stator core 402 surrounding the rotor core 401, and a housing 407 accommodating the rotor core 401 and the stator core 402.

[0104] The rotor core 401 extends along an imaginary axis of rotation VL that passes through the rotor core 401. The rotor core 401 rotates around the imaginary axis of rotation VL.

[0105] The stator core 402 is formed in a cylindrical shape that surrounds the rotor core 401. The central axis of the cylinder coincides with the imaginary axis of rotation VL. In other words, the stator core 402 is disposed coaxially with the rotor core 401. The stator core 402 has an inner surface 402a that faces the rotor core 401.

[0106] Stator core 402 is elastically held in housing 407. The structure interposed between stator core 402 and housing 407 will be described below.

[0107] The turbine generator 400 also includes a core clamping member 403 and a retaining ring 404 that each clamp the stator core 402 .

[0108] A plurality of core fastening members 403, specifically eight core fastening members 403, are arranged at intervals in the circumferential direction around the imaginary axis of rotation VL on the outer peripheral surface of the stator core 402. Each core fastening member 403 fastens the stator core 402 in the axial direction parallel to the imaginary axis of rotation VL.

[0109] A plurality of retaining rings 404, specifically four retaining rings 404, are arranged at intervals in the axial direction on the outer peripheral surface of the stator core 402. Each retaining ring 404 is shaped like a ring surrounding the imaginary axis of rotation VL and fastens the stator core 402 in a radial direction perpendicular to the imaginary axis of rotation VL. The retaining rings 404 are arranged radially outward of the core fastening members 403.

[0110] The turbine generator 400 also includes a frame ring 406 secured to the inner surface of the housing 407 , and a resilient support member 405 interposed between the frame ring 406 and the retaining ring 404 .

[0111] A plurality of inner frame rings 406, specifically five inner frame rings 406, are arranged at intervals in the axial direction on the inner surface of the housing 407. Each inner frame ring 406 is shaped like a ring surrounding the imaginary axis of rotation VL and protrudes radially inward from the inner surface of the housing 407.

[0112] The elastic support member 405 is formed in a cylindrical shape surrounding the imaginary rotation axis VL. The radially inner ends of each inner frame ring 406 are joined to the outer surface of the elastic support member 405. Meanwhile, the radially outer ends of each retaining ring 404 are joined to the inner surface of the elastic support member 405.

[0113] The elastic support member 405 is formed between a pair of adjacent inner frame rings 406 and constitutes a cylindrical leaf spring supported by the inner frame rings 406. A retaining ring 404 is joined to the axially middle portion of each leaf spring.

[0114] In the turbine generator 400 described above, the insulated coil 300 shown in Fig. 4 is attached to the stator core 402. The structure of the portion of the stator core 402 where the insulated coil 300 is attached will now be described.

[0115] As shown in Fig. 8, slots 408, which are recesses for accommodating the components, are formed on the inner surface 402a of the stator core 402. The slots 408 have a depth in the radial direction. Although not shown in Fig. 8, a plurality of slots 408 are formed on the inner surface 402a of the stator core 402 at intervals in the circumferential direction. Note that the slots 408 are not shown in Figs. 6 and 7.

[0116] 4 are housed in each slot 408. Specifically, two insulated coils 300 arranged side by side in the radial direction are housed in each slot 408. In each slot 408, a spacer 409 is interposed between the two insulated coils 300.

[0117] The opening of each slot 408 is closed by a wedge 410. The wedge 410 serves to fix the two insulated coils 300 located radially inward of the wedge 410 to the stator core 402, and also serves to suppress electromagnetic vibrations generated from the insulated coils 300 when the turbine generator 400 is in operation.

[0118] As described above, each insulated coil 300 has a structure in which the coil conductor 310 is covered with the impregnated tape 200, which is an insulator. Therefore, the coil conductor 310 is electrically insulated from the grounded stator core 402.

[0119] Hereinafter, the thickness of the insulating layer formed as a whole by the impregnated tape 200 wound multiple times around the coil conductor 310 will be referred to as the "total thickness." The impregnated tape 200 achieves electrical insulation with a higher volume resistivity than conventionally, so the total thickness can be reduced compared to conventionally. In other words, the number of times the impregnated tape 200 is wound around the coil conductor 310 can be reduced compared to conventionally. This contributes to the miniaturization of the turbine generator 400.

[0120] Alternatively, the impregnated tape 200 provides electrical insulation with a high breakdown voltage, allowing for an increase in the voltage applied to the coil conductor 310 and therefore for the turbine generator 400 to have a higher output.

[0121] The embodiment has been described above, but the following modifications are also possible.

[0122] In the third embodiment, the turbine generator 400 has been described as an example of a rotating machine according to the present disclosure, but the rotating machine is not limited to a generator including the turbine generator 400. The concept of a rotating machine includes not only a generator that converts mechanical energy into electrical energy, but also an electric motor that converts electrical energy into mechanical energy. The insulated coil 300 according to the second embodiment can be applied to any rotating machine.

[0123] Furthermore, the conductor around which the insulating tape 100 according to the first embodiment can be wound is not limited to the coil conductor 310. The insulating tape 100 can be used to insulate any type of conductor.

[0124] The present disclosure allows various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. The above-described embodiments are intended to explain the present disclosure and do not limit the scope of the present disclosure. The scope of the present disclosure is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and the meaning of the disclosure equivalent thereto are considered to be within the scope of the present disclosure.

[0125] This application is based on Japanese Patent Application No. 2024-128731, filed on August 5, 2024. The entire specification, claims, and drawings of Japanese Patent Application No. 2024-128731 are incorporated herein by reference.

[0126] 100 insulating tape, 110 tape body layer, 120 binder layer, 130 microcapsules, 131 outer shell, 132 encapsulated substance, 140 reinforcing layer, 200 impregnated tape, 300 insulating coil, 310 coil conductor, 400 turbine generator (rotating machine), 401 rotor core, 402 stator core, 402a inner surface, 403 core clamping member, 404 retaining ring, 405 elastic support member, 406 inner frame ring, 407 housing, 408 slot, 409 spacer, 410 wedge, VL imaginary rotation axis.

Claims

1. An insulating tape impregnated with a liquid resin containing at least one of a bisphenol A type epoxy compound having a repeat number of zero and a bisphenol F type epoxy compound having a repeat number of zero, comprising: a tape main layer having a structure capable of being impregnated with the liquid resin; a binder layer laminated on the tape main layer in the thickness direction of the insulating tape and constituted by a cured product of a binder attached to the tape main layer; and a plurality of microcapsules dispersed in the structure of the binder layer, wherein the microcapsules have an outer shell that begins to melt at a temperature higher than the temperature at which the cured product of the binder begins to melt; and an encapsulated substance encapsulated in the outer shell that has the property of accelerating the curing of the liquid resin, wherein the cured product of the binder is constituted by a crystalline epoxy resin having a molecular structure in which two phenyl groups are linked by a single bond, a molecular structure in which two phenyl groups are linked by an ether bond, or a molecular structure in which two phenyl groups are linked by a methylene group.

2. The insulating tape according to claim 1, wherein the encapsulated substance comprises a compound represented by the following formula (1): (In formula (1), R ａ１ , R ａ２ each independently represents an amino group or a hydroxy group, and -X- represents a single bond, an ether bond, or a bond via a methylene group.

3. The insulating tape according to claim 1, wherein the encapsulated substance comprises at least one selected from the group consisting of an imidazole group, a primary amine, a secondary amine, and a tertiary amine.

4. The insulating tape according to any one of claims 1 to 3, wherein the crystalline epoxy resin constituting the binder layer contains a compound represented by the following formula (2): (In formula (2), R ｂ１ , R ｂ２ , R ｂ３ , R ｂ４ , R ｂ５ , R ｂ６ , R ｂ７ , R ｂ８ each independently represents a hydrogen atom or a methyl group, and -Y- represents a single bond, an ether bond, or a bond formed by a methylene group.

5. The insulating tape according to any one of claims 1 to 4, wherein the viscosity of the crystalline epoxy resin constituting the binder layer at 90°C is 1.0 Pa·sec or less.

6. An insulated coil comprising: an insulating tape according to any one of claims 1 to 5; an impregnated tape having a cured product of the liquid resin impregnated into the insulating tape; and a coil conductor around which the impregnated tape is wound.

7. A rotating machine comprising: a rotating rotor core; and a stator core surrounding the rotor core and having slots formed on an inner surface facing the rotor core, wherein the slots of the stator core house the insulated coil according to claim 6.

8. A method for manufacturing an insulated coil, comprising: an insulating tape winding step of winding the insulating tape according to any one of claims 1 to 5 around a coil conductor; an impregnation step of impregnating the insulating tape wound around the coil conductor with the liquid resin at a temperature at which the cured product of the binder melts; and a heating step of heating the insulating tape impregnated with the liquid resin to promote melting of the outer shell of the microcapsule.

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