Insulation material and rotary electric device comprising same

Abstract

The present invention relates to an insulation material and a rotary electric device comprising same, the insulation material being provided between a slot and a coil in a stator of a rotary electric device, and being formed by curing a resin insulating material composition that comprises an epoxy resin, a curing agent, an inorganic filler and a catalyst, wherein crystal silica is included as the inorganic filler, and, when the resin insulating material composition is cured at a temperature of 175°C, the hardness (175°C hardness) measured by a Shore D hardness tester is 80 HSD or more.

Description

Insulating materials and rotating electrical machines containing the same

[0001] The present invention relates to an insulating material and a rotating electric machine including the same.

[0002]

[0003] A rotating electrical device such as a motor or a generator includes a rotor and a stator, and the stator has an annular stator core having a plurality of slots in the circumferential direction of the inner surface. A coil is wound around the slots, and an insulating layer is formed between the slots and the coils in the stator to ensure electrical insulation.

[0004] Conventionally, a method has been used to form an insulating layer by inserting insulating paper between slots and coils in a stator. In order to insert insulating paper into a rotating electric machine according to the above method, a process of unwinding and supplying the insulating paper, cutting it, bending it to have a predetermined shape, and then inserting it into a slot or the like in the rotating electric machine is required. Various technologies have been proposed in relation to the insulating paper and a device for manufacturing the same. For example, Korean Patent Publication No. 10-1999-0015205 discloses an insulating paper for a motor in which both wings and a fixing member for fixing the wings are formed as one piece, and a device for manufacturing the same.

[0005] However, since a single manufacturing device can only produce one type of insulating paper, separate insulating paper manufacturing devices must be used for each shape to manufacture insulating paper of various shapes used in various types of rotating electrical machines, resulting in significant inefficiencies in terms of cost and time. Furthermore, conventional insulating paper has the problem of low thermal conductivity, making it difficult to sufficiently suppress temperature rise in rotating electrical machines.

[0006] Recently, a technology has been proposed to increase thermal conductivity and further improve insulation by using a resin composition with high thermal conductivity instead of insulating paper. To form an insulation portion within a stator using a resin composition, a process of injecting the molten resin composition into a slot is required. At this time, in order to form the insulation portion with a certain shape and thickness, a core pin is provided within the slot, and after the resin composition hardens to form an insulating material, it is removed from the slot. When the core pin is removed, scratches may occur at the interface between the hardened insulating material and the core pin. Since the formed insulating material is very thin, approximately 100 to 400 um, the scratches may develop into microcracks during subsequent processes or during the operation of a high-speed rotating machine, resulting in a problem of poor insulation properties.

[0007] Meanwhile, when molding insulation within a stator, while a short curing time improves productivity and cure rate, considering the filling properties of the resin composition, a long curing time is required. However, conventional resin compositions for insulation materials have long curing times, resulting in poor curability, low high-temperature hardness during molding, and, as a result, deep scratches can form on the insulation surface when removing the core pin.

[0008] Accordingly, an insulating material is required that provides sufficient molding time to the resin composition for insulating material, while also having excellent insulating properties, high-temperature hardness, and scratch resistance.

[0009]

[0010] The present invention provides an insulating material having excellent insulating properties, high-temperature hardness, and scratch resistance, while providing a sufficient molding time for a resin composition for insulating materials. The present invention also provides a rotating electric machine equipped with the insulating material.

[0011]

[0012] The present invention provides an insulating material formed by curing an insulating resin composition comprising an epoxy resin, a curing agent, an inorganic filler, and a catalyst, which is provided between a slot and a coil in a stator of a rotating electric machine, wherein the insulating resin composition comprises crystal silica as the inorganic filler, and when the insulating resin composition is cured at a temperature of 175°C, the insulating material has a hardness (175°C hardness) of 80 HSD or higher as measured by a Shore D durometer.

[0013]

[0014] The present invention provides an insulating material having excellent insulation properties, high-temperature hardness, and scratch resistance while providing a sufficient molding time for a resin composition for insulation. The insulating material according to the present invention can be filled between a slot and a coil in a rotating electric machine, filling the gap between the slot and the coil and replacing insulating paper to impart insulating properties. The insulating material of the present invention has excellent thermal conductivity and insulation properties, and has excellent scratch resistance due to a core pin during molding of an insulating portion, making it applicable to rotating electric machines, such as electric vehicle motors, where high torque is required and thus the rotational speed and current applied to the stator increase.

[0015]

[0016] The present invention will be described in detail below. However, the scope of the present invention is not limited solely to the details described below, and each component may be modified or selectively mixed as needed. Therefore, it should be understood that all modifications, equivalents, and alternatives included within the spirit and technical scope of the present invention are encompassed.

[0017] As used herein, “viscosity” is measured by a conventional method known in the art, and can be measured, for example, using an ICI viscometer at 150°C. Functional values ​​such as “hydroxyl value” are measured by a conventional method known in the art, and can be measured, for example, by a titration method. “Particle size (D50)” is measured by a conventional method known in the art, and can be measured, for example, by laser light scattering (LLS).

[0018]

[0019] Insulating material

[0020] The insulating material of the present invention is provided between a slot and a coil in a stator of a rotating electric machine, and is an insulating material formed by curing a resin composition for insulating material including an epoxy resin, a curing agent, an inorganic filler, and a latent catalyst, wherein the inorganic filler includes crystal silica.

[0021] The insulating material of the present invention is formed by curing an insulating resin composition, and serves to replace conventional insulating paper. The insulating resin composition can be formed into a thin layer (e.g., about 100 to 400 um) between a slot and a coil in a stator of a rotating electric machine. However, when a core pin placed inside the slot is removed after forming to form an insulating portion with a certain shape and thickness, scratches may occur at the interface between the insulating material and the core pin. The insulating material of the present invention has excellent high-temperature hardness, thereby improving surface hardness and providing excellent scratch resistance. As a result, when the core pin is removed, scratches do not occur at the interface, thereby preventing damage from microcracks during a subsequent process of manufacturing a rotating machine or during high-speed rotation of the manufactured rotating machine, and providing excellent durability and excellent reliability.

[0022] The resin composition for insulating material according to the present invention, when cured at a temperature of 175°C, has a hardness (175°C hardness) measured by a Shore D durometer of 80 HSD or higher, for example, 80 to 150 HSD, or another example, 83 to 100 HSD. The higher the hardness (175°C hardness) measured by the Shore D durometer, the more the occurrence of scratches at the interface between the cured insulating material and the core pin is suppressed when the core pin is removed from inside the slot, thereby improving microcracks and durability. If the 175°C hardness is less than the above-mentioned range, the release property may be reduced due to insufficient curing, making it difficult to remove the core pin, and appearance defects such as scratches may occur during removal. The hardness can be measured by the following method. Immediately after molding a circular specimen (diameter 30 mm, thickness 3 mm) using the above resin composition for insulating material using a transfer molding press (conditions of 175 ℃, 120 sec., 70 kgf / ㎠), the hardness at three arbitrary points on the outer surface of the specimen was measured using a Shore D durometer, and the average value was set as the hardness of 175 ℃.

[0023] The above insulating material may have a degree of curing (curing torque, 175 ℃, 120 sec.) of 60 kgf·cm or more, for example, 60 to 200 kgf·cm, or another example, 75 to 150 kgf·cm. The higher the degree of curing of the insulating material, the better the durability, high-temperature hardness, and scratch resistance. If the degree of curing is less than the above-mentioned range, the release property may be reduced due to insufficient curing, making it difficult to remove the core pin, and appearance defects such as scratches may occur during removal. The degree of curing may be measured by the following method. The degree of curing of a resin composition for insulating material (diameter 28 mm, 6.5 g) over time was measured using a Curelastometer (under constant temperature conditions of 175 ℃).

[0024] The above insulating material has a degree of curing (curing torque, 175 ℃, 300 sec.) of 100 kgf·cm or more, for example, 100 to 250 kgf·cm. As another example, it may be 100 to 200 kgf·cm. The higher the degree of curing of the insulating material, the better the durability, high-temperature hardness, and scratch resistance. If the degree of curing is less than the above-mentioned range, the curing properties such as glass transition temperature and strength may deteriorate due to the low curing rate, and an additional high-temperature curing process may be required to increase the curing rate. The degree of curing can be measured by the following method. The degree of curing of a resin composition for an insulating material (diameter 28 mm, 6.5 g) over time was measured using a Curelastometer (under constant temperature conditions of 175 ℃).

[0025] The above insulating material may have a gel time (175°C) of 40 to 70 seconds. If the gel time is less than the above-mentioned range, the filling property may be insufficient, and if it is more than the above-mentioned range, the curing property may be insufficient.

[0026] The resin composition for insulating materials according to the present invention comprises an epoxy resin, a curing agent, an inorganic filler, and a catalyst. The resin composition for insulating materials may further comprise additives commonly used in the relevant technical fields, such as adhesion enhancers, release agents, colorants, and flame retardants, as needed.

[0027]

[0028] epoxy resin

[0029] The resin composition for insulating material of the present invention comprises an epoxy resin. The epoxy resin serves as a main agent to improve the reliability of the resin composition for insulating material.

[0030] As the epoxy resin, an epoxy resin commonly used in the relevant technical field can be used, and for example, one containing two or more epoxy groups in its molecular structure can be used. Non-limiting examples of epoxy resins that can be used include bisphenol-based epoxy resins, alicyclic epoxy resins, cresol novolac-based epoxy resins, biphenyl-based epoxy resins, naphthalene-based epoxy resins, polyfunctional epoxy resins, anthracene-based epoxy resins, non-condensed ring-based polycyclic structure epoxy resins, bisphenol fluorene-modified epoxy resins, and the like, and one or more of these may be further included.

[0031] For example, the epoxy resin may be an ortho-cresol novolac epoxy resin, for example, a formaldehyde polymer with (chloromethyl)oxirane and 2-methylphenol.

[0032] The epoxy resin may have an epoxy equivalent of 180 to 300 g / eq, for example, 200 to 220 g / eq, and a viscosity (150°C) of 0.02 to 15 poise, for example, 4 to 5 poise. If the equivalent and viscosity of the epoxy resin are less than the above ranges, the resin composition for insulating material may leak through the gaps of the mold during molding, resulting in poor moldability and appearance, and reduced mechanical properties after curing. If they exceed the above ranges, the flowability of the resin composition for insulating material may be insufficient, resulting in reduced filling properties and adhesive strength.

[0033] Based on the total weight of the resin composition for insulating material, the content of the epoxy resin may be 1 to 20 wt%, for example, 5 to 15 wt%. If the content of the epoxy resin is less than the above-mentioned range, uniformity may be reduced during the production of the composition, and filling properties and adhesiveness may be reduced due to insufficient flowability. If the content of the epoxy resin is more than the above-mentioned range, the content of the filler may be reduced, resulting in a decrease in mechanical strength.

[0034]

[0035] hardener

[0036] The resin composition for insulating material according to the present invention includes a curing agent. The curing agent reacts with the epoxy resin, and through curing, seals the stator slots and coils, thereby imparting insulating properties to the stator. Furthermore, the curing agent serves to raise the glass transition temperature.

[0037] The curing agent may be any curing agent known in the art that undergoes a curing reaction with an epoxy resin. For example, the curing agent may be a phenol-based compound having two or more phenolic hydroxyl groups in one molecule. For example, the curing agent may include at least one selected from the group consisting of an acid anhydride compound, a phenol novolac resin, a cresol novolac resin, a phenol aralkyl resin, and a polyfunctional phenol compound. For example, the curing agent may be a phenol polymer with formaldehyde. In this case, excellent chemical resistance and curing properties may be provided.

[0038] The above-mentioned hardener may be used with a viscosity (150°C) of 0.5 to 10 poise. If the viscosity is below the above-mentioned range, the resin composition for insulating material may leak through the gaps in the mold during molding. If the viscosity exceeds the above-mentioned range, the uniformity may be reduced during composition production, and the filling property and adhesiveness may be reduced during molding.

[0039] The above-mentioned hardener may be used having a hydroxyl equivalent of 100 to 230 g / eq, for example, 100 to 110 g / eq. If the hydroxyl equivalent is less than the above-mentioned range, the resin composition for insulating material may leak through the gap between the mold during molding, and if it exceeds the above-mentioned range, the uniformity may be reduced during the composition production, and the filling property and adhesiveness may be reduced during molding.

[0040] Based on the total weight of the resin composition for insulating material, the content of the curing agent may be 0.1 to 15 wt%, for example, 1 to 10 wt%. If the content of the curing agent is less than the above-mentioned range, curability and moldability may be reduced, and if it exceeds the above-mentioned range, reliability and strength may be reduced due to increased moisture absorption.

[0041]

[0042] Weapon filler

[0043] The resin composition for insulating materials according to the present invention includes an inorganic filler. The inorganic filler imparts strength to the resin composition for insulating materials, controls flowability, thereby enhancing formability and durability.

[0044] The above inorganic filler may be formed of any one or a combination of at least two selected from non-metal oxides, metal nitrides, non-metal nitrides, inorganic hydrates, or inorganic salts, and for example, silica, silica nitride, alumina, alumina nitride, boron nitride, etc. may be used in combination.

[0045] The above inorganic filler may include silica (crystal silica), and in this case, it can provide excellent strength at high temperatures. Crystalline silica has a thermal conductivity 10 times or more higher than that of fused silica and a high coefficient of thermal expansion, and the difference from the coefficient of thermal expansion of coils such as copper is small. Therefore, when an insulating resin composition containing crystalline silica as an inorganic filler is used as an insulating material to fill a space between a slot and a coil in a stator, internal stress is reduced, thereby improving reliability and formability. In addition, by providing a sufficient forming time to the insulating resin composition and improving high-temperature hardness, when manufacturing an insulating material using the above insulating resin composition, sufficient strength and high-temperature dimensional stability can be provided even when the manufactured insulating material is exposed to a harsh environment (high temperature, high pressure, etc.), thereby improving scratch resistance caused by a core pin, and suppressing the occurrence of cracks in the insulating material. For example, the crystalline silica may have an average particle diameter (D 50 ) can be used having a size of 1 to 30 μm, for example, 5 to 15 μm.

[0046] The above inorganic filler may further include fused silica. In this case, the viscosity and flowability of the resin composition for insulating material can be controlled to further improve the formability. For example, the average particle diameter (D) of the fused silica 50 ) can be used having a size of 1 to 30 μm, for example, 5 to 15 μm.

[0047] Based on the total weight of the resin composition for insulating material, the content of the inorganic filler may be 70 to 90 wt%, for example, 75 to 85 wt%. If the content of the inorganic filler is less than the above-mentioned range, the mechanical strength of the cured product of the resin composition for insulating material may decrease and the moisture absorption may increase, thereby reducing reliability. In addition, when the resin content is excessive and exposed to high temperatures, the resin may decompose, increasing the high-temperature mass loss rate and reducing the insulation. In addition, if the content exceeds the above-mentioned range, fluidity may decrease, resulting in poor moldability.

[0048] For example, based on the total weight of the inorganic filler, the composition may contain 10 to 50 wt% of the crystalline silica and 50 to 90 wt% of the fused silica. In this case, the resin composition for insulating material may be strengthened, thereby further improving the formability. If the content of the crystalline silica is less than the above-mentioned range, the high-temperature hardness may decrease during molding, which may lower the scratch resistance, and if it exceeds the above-mentioned range, the flowability may decrease, which may lower the filling property.

[0049]

[0050] catalyst

[0051] The resin composition for insulating materials according to the present invention includes a catalyst. The catalyst serves to improve curing speed and workability. The catalyst may include a latent catalyst. In this case, the resin composition for insulating materials provides sufficient molding time while simultaneously improving high-temperature hardness, thereby enhancing the scratch resistance of the insulating material.

[0052] The latent catalyst may include a latent imidazole catalyst, a latent phosphorus catalyst, etc. For example, the latent catalyst includes a latent imidazole catalyst and a latent phosphorus catalyst.

[0053] As the above potential imidazole catalyst, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,4-diamino-6-(2-ethyl-4-methylimidazolyl-(1))-ethyl-s-triazine, 2-phenyl-4,5-dihydroxymethylimidazole, etc. can be used.

[0054] As the above-mentioned latent phosphorus catalyst, a carboxylate phosphorus catalyst, a naphthalene phosphorus catalyst, a catechol phosphorus catalyst, a benzoquinone phosphorus catalyst, etc. can be used. For example, the above-mentioned latent phosphorus catalyst may be a naphthalene phosphorus latent catalyst.

[0055] Based on the total weight of the resin composition for insulating material, the content of the catalyst may be 0.1 to 4 wt%, for example, 0.2 to 2 wt%. For example, based on the total weight of the resin composition for insulating material, the latent imidazole-based catalyst may be included in an amount of 0.05 to 2 wt%, for example, 0.1 to 1 wt%, and the latent phosphorus-based catalyst may be included in an amount of 0.05 to 2 wt%, for example, 0.1 to 1 wt%.

[0056]

[0057] additives

[0058] The resin composition for insulating material according to the present invention may further include additives commonly used in the relevant technical field, such as an adhesion enhancer, a release agent, a colorant, a flame retardant, etc., as needed.

[0059] The adhesion enhancer is intended to improve the bonding between organic and inorganic materials and the adhesion to the metal substrate, and may include epoxy silane, amino silane, mercapto silane, acrylic silane, vinyl silane, etc. The release agent is intended to improve the release property between the EMC and the external mold, and may include both-terminal amine-modified silicone oil, paraffin wax, carnauba wax, polyethylene wax, ester wax, long-chain fatty acid, metal salt of long-chain fatty acid, etc. In addition, the resin composition may further include additives such as a coloring agent (e.g., carbon black, Bengala, etc.) for imparting color, a flame retardant (e.g., metal hydroxide, etc.).

[0060] The above additives may be added within a content range that does not impair the properties of the resin composition for insulating material of the present invention, and for example, may be included in an amount of 0.01 to 10 wt%, respectively, based on the total weight of the resin composition for insulating material, but are not limited thereto.

[0061]

[0062] <Rotating electrical machine>

[0063] The present invention provides a rotating electric machine equipped with the aforementioned insulating material. The rotating electric machine may be a component for a vehicle.

[0064] For example, the present invention provides a rotating electric machine including a rotor and a stator, wherein the stator has an annular stator core having a plurality of slots in a circumferential direction of an inner surface, a coil is wound around the slots, and an insulating material according to the present invention is provided between the slots and the coils.

[0065] The insulating material according to the present invention provides sufficient EMC molding time, and has excellent insulation properties, high-temperature hardness, and scratch resistance, so that it can be applied as an insulating material that provides insulating properties to rotating electric machines, such as motors for electric vehicles, where the rotational speed and the current applied to the stator increase as a large torque is required.

[0066]

[0067] Hereinafter, the present invention will be described in more detail through examples. However, the following examples are intended only to aid understanding of the present invention and are not intended to limit the scope of the present invention in any way.

[0068]

[0069] [Experimental Example 1-12]

[0070] According to the compositions described in Tables 1 and 2 below, each component was mixed to prepare a resin composition for insulating material of each experimental example. Using the resin composition for insulating material prepared according to each experimental example, a circular specimen (diameter 30 mm, thickness 3 mm) was molded using a transfer molding press (conditions of 175 ℃, 120 sec., 70 kgf / ㎠), and immediately thereafter, the hardness at three arbitrary points on the outer surface of the specimen was measured using a Shore D durometer, and the average value was taken as the high-temperature hardness, and the results are described in Tables 1 and 2 below.

[0071]

[0072]

[0073]

[0074]

[0075]

[0076] Epoxy resin: Orthocresol novolac type epoxy resin (YDCN500-4P, Kukdo Chemical, softening point 62 ℃, epoxy equivalent 201 g / eq, melt viscosity (150 ℃) 0.3 poise)

[0077] Hardener: Phenol resin (KPH-F2001, Kolon, softening point 84 ℃, hydroxyl equivalent 107 g / eq, melt viscosity (150 ℃) 2.0 poise)

[0078] Inorganic filler 1: Fused silica(D 50 13.5 ㎛)

[0079] Inorganic filler 2: Crystal silica(D50 7.5 ㎛)

[0080] Catalyst 1: Triphenyl phosphine

[0081] Catalyst 2: Latent imidazole catalyst (2-phenyl-4-methyl-5-hydroxymethylimidazole)

[0082] Catalyst 3: Potential phosphorus transfer catalyst (naphthalene phosphorus transfer catalyst, XNH-2202, Shina T&C)

[0083] Additive 1: Epoxy silane (S-510, CHISSO Corporation)

[0084] Additive 2: Carnauba wax

[0085] Additive 3: Carbon black

[0086] Additive 4: Aluminum hydroxide

[0087]

[0088] [Physical property evaluation]

[0089] The properties of the resin composition for insulation in each experimental example were measured using the following method, and the results are shown in Tables 3 and 4 below.

[0090]

[0091] Spiral flow (S / F)

[0092] The resin composition for insulating material manufactured according to each experimental example was subjected to flow measurement using a transfer molding press under conditions of 175 ℃ / 120 sec., 70 kgf / ㎠ using an evaluation mold according to EMMI-1-66.

[0093]

[0094] Gel Time (G / T)

[0095] On a 175 ℃ hot plate, a thin layer of resin composition powder for insulation prepared according to each experimental example was applied and the gelation time was measured.

[0096]

[0097] Curing torque

[0098] Using a Curelastometer (at a constant temperature of 175°C), the curing degree over time of the resin composition for insulating material (diameter 28 mm, 6.5 g) manufactured according to each experimental example was measured.

[0099]

[0100]

[0101]

[0102]

[0103]

[0104] As shown in Tables 3 and 4 above, the insulating materials of Experimental Examples 1-9 according to the present invention exhibited excellent physical properties across all measured items. On the other hand, it can be confirmed that the insulating materials of Experimental Examples 10, 11, and 12, which were formed by curing an insulating resin composition having a hardness (175°C hardness) of less than 80 HDS as measured by a Shore D durometer, have a lower degree of curing than Experimental Examples 1-9 of the present invention, and when the core pin is removed after forming an insulating material using the same, scratches may occur on the surface.

[0105]

[0106] The present invention provides an insulating material having excellent insulating properties, high-temperature hardness, and scratch resistance, while providing a sufficient molding time for a resin composition for insulating materials. The present invention also provides a rotating electric machine equipped with the insulating material.

Claims

1. It is provided between the slot and coil in the stator of a rotating electric machine. An insulating material formed by curing a resin composition for insulating material comprising an epoxy resin, a hardener, an inorganic filler, and a catalyst, An insulating material having a hardness (175°C hardness) of 80 HDS or higher as measured by a Shore D durometer when the resin composition for the insulating material is cured at a temperature of 175°C.

2. In the first paragraph, an insulating material having a degree of curing (curing torque, 175 ℃, 120 sec.) of 60 kgf·cm or more and a degree of curing (curing torque, 175 ℃, 300 sec.) of 100 kgf·m or more.

3. In the first paragraph, the epoxy equivalent of the epoxy resin is 180 to 300 g / eq, and the viscosity (150°C) is 1 to 10 poise, An insulating material having a viscosity (150°C) of the above-mentioned hardener of 0.5 to 10 poise and a hydroxyl equivalent of 100 to 230 g / eq.

4. In the first paragraph, the inorganic filler comprises crystal silica and fused silica, An insulating material comprising 10 to 50 wt% of the crystal silica based on the total weight of the inorganic filler.

5. In the first paragraph, the catalyst comprises a latent catalyst, An insulating material comprising the above-mentioned potential catalyst, a potential imidazole-based catalyst, a potential phosphorus-based catalyst, or a mixture thereof.

6. An insulating material comprising, in paragraph 1, 1 to 20 wt% of the epoxy resin, 0.1 to 15 wt% of the curing agent, 70 to 90 wt% of the inorganic filler, and 0.1 to 4 wt% of the catalyst, based on the total weight of the resin composition for the insulating material.

7. Contains a rotor and a stator, The above stator has a circular stator core having a plurality of slots in the circumferential direction of the inner surface, A coil is wound in the above slot, A rotating electric machine having an insulating material according to any one of claims 1 to 6 between the slot and the coil.

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