A coating method for corona-resistant enameled wire

Abstract

The present invention discloses a coating method for a corona-resistant enameled wire: during the feeding process of the copper wire, firstly, a positive spiral coating is coated by rotating around the copper wire clockwise, and a preliminary curing is performed; after the positive spiral coating is formed, a reverse spiral coating is coated by rotating around the copper wire counterclockwise, and a preliminary curing is performed again to form a reverse spiral coating; multiple layers of positive and reverse coating are repeated; and a final curing is performed; the method adopts a cross-coating technology of positive spiral and reverse spiral, which significantly enhances the mechanical strength and electrical insulation performance of the coating. By precisely controlling the thickness and width of the coating, and using an improved coating formula, the present invention can provide a more uniform and continuous coating, effectively preventing corona discharge and coating cracking. In addition, the present invention also introduces an automatic coating replenishment system using centrifugal action, which greatly improves the application efficiency of the coating and the automation level of the production process.

Description

Technical Field

[0001] The invention relates to the technical field of enameled wire processing, and more particularly to a coating method for a corona-resistant enameled wire. Background Art

[0002] In the field of electrical engineering, enameled wire is an important material widely used in equipment such as motors, transformers, and electromagnetic coils. Traditional enameled wire coating technology usually involves continuous coating in a single direction. Although this method is simple, it has several shortcomings. First, unidirectional continuous coating may cause the coating to crack and peel easily under mechanical stress, affecting the durability and reliability of the product. Secondly, this coating method is prone to corona discharge in high-voltage applications because the uniformity and thickness of the coating are difficult to accurately control. In addition, there is room for improvement in traditional coating technology in terms of coating application efficiency and energy consumption.

[0003] With the development of technology and the increase in market demand, the performance requirements for enameled wires are also increasing. In particular, the requirements for electrical insulation, mechanical strength, high temperature resistance and chemical stability have increased significantly. Therefore, it has become an urgent need for the industry to develop a new coating technology that aims to provide superior electrical insulation performance, higher mechanical and thermal stability, as well as higher production efficiency and material utilization. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention proposes an innovative method for coating corona-resistant enameled wire, which adopts the cross-coating technology of positive spiral and reverse spiral, significantly enhancing the mechanical strength and electrical insulation performance of the coating. By precisely controlling the thickness and width of the coating and using an improved coating formula, the present invention can provide a more uniform and continuous coating, effectively preventing corona discharge and coating cracking. In addition, the present invention also introduces an automatic coating replenishment system using centrifugal action, which greatly improves the application efficiency of the coating and the automation level of the production process.

[0005] To solve the above problems, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a method for coating a corona-resistant enameled wire, comprising the following steps:

[0007] During the feeding process of the copper wire, the strip-shaped positive spiral coating is firstly applied by rotating around the copper wire in a clockwise direction and then initially cured;

[0008] After the positive spiral coating is formed, the copper wire is rotated counterclockwise to coat a ribbon-shaped reverse spiral coating, and then the coating is initially cured again to form a reverse spiral coating;

[0009] Repeatedly apply multiple layers alternately in front and back directions;

[0010] Carry out final curing;

[0011] The coating of one of the positive helical coating and the reverse helical coating comprises the following components: 50-60 parts by weight of epoxy resin, 3-5 parts by weight of silane coupling agent, 15-25 parts by weight of aluminum hydroxide, 5-10 parts by weight of phthalate plasticizer, 10-15 parts by weight of acid anhydride curing agent, and 1-3 parts by weight of hindered phenol antioxidant;

[0012] The coating of another coating layer comprises the following components: 40-50 parts by weight of polyimide resin, 10-20 parts by weight of nano-silicon dioxide, 5-10 parts by weight of graphene, 5-10 parts by weight of polyvinyl alcohol softener, 10-20 parts by weight of alicyclic amine curing agent, and 2-5 parts by weight of benzotriazole ultraviolet absorber.

[0013] Preferably, the preliminary curing is performed by ultraviolet curing, and the UV intensity is set to 800 to 1200 mJ / cm 2 .

[0014] Preferably, the final curing is thermal curing, with the curing temperature set at 180° C. to 220° C. and the duration being 10 to 30 minutes.

[0015] Preferably, the copper wire feeding speed is set at 100 m / min to 500 m / min, and the copper wire rotation speed is set at 300 to 1000 revolutions per minute.

[0016] Preferably, the band width, i.e., bandwidth, of the positive helical coating is the same as that of the reverse helical coating, and the pitch of the spirals of the positive helical coating and the reverse helical coating is the same as their bandwidth; adjacent positive helical coatings and reverse helical coatings are arranged crosswise; and two adjacent positive helical coatings or two adjacent reverse helical coatings are staggered by half the bandwidth.

[0017] Preferably, the coating method is implemented by a coating device; the coating device includes a plurality of spiral coating mechanisms and an ultraviolet curing mechanism arranged between two adjacent spiral coating mechanisms; the copper wire is fed through the spiral coating mechanism and the ultraviolet curing mechanism in sequence; the spiral coating mechanism includes a positive coating component and a negative coating component; the positive coating component and the negative coating component each include a U-shaped bearing shoe seat and a coating ring body rollingly supported on the U-shaped bearing shoe seat; a coating block in contact with the outer circumferential surface is arranged in the middle of the coating ring body; the length of the coating block is equal to the bandwidth; the distance between the coating blocks of the positive coating component and the negative coating component is an integer multiple of the bandwidth; the coating ring bodies of the positive coating component and the negative coating component rotate in opposite directions and have the same rotation speed.

[0018] More preferably, a rack is provided on the outer circumferential surface of the coating ring body along its circumference; the rack is meshed with a gear arranged outside the coating ring body; a driving motor drives the gear arranged above the coating ring body to drive the coating ring body to rotate; the positive coating component and the negative coating component also include a positive synchronous gear and a negative synchronous gear respectively; the positive synchronous gear rotates coaxially with the gear corresponding to the positive coating component; the negative synchronous gear rotates coaxially with the gear corresponding to the negative coating component; the positive synchronous gear and the negative synchronous gear are symmetrical and have a spacing; a bevel gear is meshed with the positive synchronous gear and the negative synchronous gear at the same time to make the coating ring bodies of the positive coating component and the negative coating component rotate synchronously and reversely.

[0019] More preferably, the coating ring body is a hollow ring body having an annular cavity; the annular cavity is filled with coating; the coating block is connected to the coating ring body via a hollow cylinder; one end of the hollow cylinder is detachably connected to the coating block and a discharge port is provided on the side, and the other end penetrates into the annular cavity and is connected to the outer inner wall of the annular cavity and a feed port is provided on the side; a small liquid pump is provided in the hollow cylinder to assist the coating to flow to the side of the discharge port.

[0020] More preferably, there are multiple groups of coating blocks arranged in the coating ring body, and the distance along the axial direction between two adjacent groups of coating blocks is an integer multiple of the width of the strip coating.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. Good corona resistance:

[0023] The positive and negative spiral alternating coating technology used creates a woven coating structure. This structure not only enhances the mechanical strength of the coating, but also improves the overall tightness of the coating and reduces the presence of air gaps. In electrical engineering, air gaps are often the starting point of corona discharge. By reducing these tiny air gaps, the risk of corona discharge is significantly reduced.

[0024] Optimization of coating formulation, epoxy resin and polyimide resin are both well-known materials with high electrical insulation properties. Epoxy resin provides good mechanical strength and adhesion, while polyimide resin is known for its excellent thermal stability and electrical insulation. The combination of these materials enables the coating to maintain good electrical insulation not only at room temperature but also at high temperatures, thereby effectively resisting corona discharge.

[0025] Nano-scale silica and graphene: These nanomaterials can improve the microstructure of the coating, increase the dispersion in the electric field, and improve the coating's ability to block corona discharge. Nanofillers such as silica can enhance the electrochemical stability of the coating, while graphene helps to even out the electric field and reduce the electric field concentration points, which is a common cause of corona discharge. Although graphene has very high electrical conductivity, the addition of graphene can improve the insulation properties and other mechanical and thermal properties of the coating through appropriate proportions and processes:

[0026] When added in trace amounts, the conductivity of graphene can be "masked" by the insulating properties of the coating matrix and will not significantly affect the overall insulation performance. Instead, graphene can enhance the overall insulation performance of the material through the following mechanisms:

[0027] Optimization of microscopic electric field distribution: The conductivity of graphene can help disperse the microscopic electric field inside the coating, reduce electric field concentration, and reduce the risk of corona discharge. Graphene fragments act as tiny conductive channels, which help to evenly distribute the charge inside the material, thereby avoiding the formation of high voltage points.

[0028] Improved interface properties: The addition of graphene can improve the interfacial bonding between the coating and the copper wire and reduce the air gap at the interface, which is a potential starting point for corona discharge. By improving the overall quality of the interface, the electrical insulation properties of the wire can be further improved.

[0029] Graphene has very high thermal conductivity and can effectively improve the thermal management capabilities of coatings. This is particularly important in electrical applications, because if the heat generated by wires during operation cannot be effectively dissipated, it will lead to heat accumulation, which will affect the performance and life of the insulation material. The addition of graphene helps to evenly distribute the heat energy inside the coating, reduce the generation of hot spots, thereby reducing thermal stress and avoiding physical or chemical degradation caused by high temperature.

[0030] Graphene's structure makes it ideal for enhancing the mechanical strength of coatings. Its high strength and toughness properties can significantly improve the coating's ability to resist stretching and bending. The layered structure helps increase the coating's fracture toughness and reduce damage under physical impact.

[0031] In summary, by precisely controlling the addition ratio of graphene and ensuring its uniform dispersion in the coating, these unique properties of graphene can be fully utilized to enhance the electrical insulation and other mechanical, thermal and chemical properties of the coating, bringing unexpected positive effects, thereby improving the overall performance and reliability of the enameled wire.

[0032] The application of curing technology not only speeds up the production process, but also ensures the uniformity and integrity of the coating at the microscopic level. UV curing can quickly cure the surface layer to form a solid protective layer, while the subsequent thermal curing ensures that the deep layer of the coating is also fully cured, enhancing the integrity of the coating. During the curing process, bubbles and irregular gaps inside the coating are effectively eliminated, reducing the probability of corona discharge.

[0033] 2. Improve strength and extend service life

[0034] The braided effect means that the coating overlaps in a staggered manner, similar to the weave or braid structure in a fiber fabric. This structure increases the mechanical robustness of the coating itself, making the coating more resistant to external pressure and impact. In high-stress applications such as motors and transformers, this increased mechanical strength reduces the likelihood of wire failure due to mechanical fatigue or physical damage in operation.

[0035] The braided structure provides improved thermal stability through its staggered layer design. When temperature changes cause the material to naturally expand or contract, the braided structure allows the coating to fine-tune its morphology while maintaining overall stability. This reduces internal stress caused by temperature changes, especially in environments with large temperature differences, such as outdoor applications or inside electronic devices.

[0036] In traditional single-directional coatings, the continuity and uniformity of the coating may cause cracks under physical or thermal stress. In contrast, the interlaced coating of the woven structure can more effectively distribute these stresses and prevent the formation of cracks. This structure is particularly suitable for preventing cracks from propagating from one coating layer to another, thereby maintaining the integrity of the overall coating.

[0037] All of these properties – enhanced mechanical strength, improved thermal stability and crack resistance – work together to significantly extend the service life of coated copper wire. Longer service life means less maintenance requirements and less frequent replacements, bringing economic benefits to companies using this technology.

[0038] Through this braiding effect, the coating method not only provides substantial physical and mechanical improvements, but also has the potential to reduce long-term operating costs due to maintenance and replacement. This design innovation provides significant advantages, especially in applications that require wires to have extremely high reliability and durability, such as aviation, automotive and advanced electronic devices. Such coating technology allows products to operate in more demanding conditions while maintaining performance and safety.

[0039] 3. The coating device of the present invention is exquisitely designed and can effectively implement the above coating method, provide multiple beneficial effects, and enhance production efficiency and product quality:

[0040] The coating device includes a positive coating component and a reverse coating component, which are equipped with a U-shaped bearing shoe and a coating ring to ensure the precise application of the coating. Through the synchronous counter-rotation design, the equipment can accurately apply staggered positive and reverse spiral coatings on the copper wire, thereby producing a uniform and continuous weaving effect, enhancing the mechanical and electrical properties of the coating.

[0041] By keeping the ribbon coating width the same for both the positive and negative helical coatings and the same pitch as the helical coating, uniformity of the coating can be achieved, which is critical to ensuring the overall insulation performance of the coating. A uniform coating helps prevent electrical shorts and corona discharges because there is no uneven resistance caused by varying thickness of the coating. The same width and pitch of the helical coating help form a balanced and continuous structure, similar to a braid, which can provide better stability under mechanical and thermal stress.

[0042] The cross-coating (i.e., the cross-covering of the positive spiral coating and the reverse spiral coating) increases the mechanical interlocking between the coatings. This structure is similar to a braid and can significantly improve the bending and torsion resistance of the copper wire. This is an important performance improvement for wires that often need to be bent or twisted at various angles. By staggering the width of the strip coating between two adjacent positive spiral coatings or two adjacent reverse spiral coatings by half, interlayer peeling can be effectively prevented, which is particularly important when the wire is subjected to mechanical stress and helps maintain the integrity of the coating.

[0043] The length of the coating block is equal to the strip coating width. This design ensures that each coating accurately covers the entire strip width, avoiding overlapping or insufficient coating, thereby optimizing the use of paint and reducing waste.

[0044] The coating rings of the positive coating component and the reverse coating component rotate simultaneously in opposite directions and at the same speed. This synchronous operation ensures the continuity and uniformity of the coating and prevents uneven coating thickness that may be caused by inconsistent rotation speed.

[0045] By precisely controlling the position of the coating block and the rotation speed of the coating ring, the entire coating process can be carried out more quickly and continuously, greatly improving production efficiency.

[0046] Precise coating application and efficient production processes reduce material waste and production downtime, thereby reducing production costs.

[0047] The combined effect of these design decisions makes the coating process not only efficient and economical, but also ensures high product quality and reliability, meeting the stringent requirements for electrical safety and durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 Schematic diagram of the positive spiral coating of the present invention;

[0049] Figure 2 It is a schematic diagram of cross-coating of a positive helical coating and a reverse helical coating of the present invention;

[0050] Figure 3 A schematic diagram of coating between adjacent positive spiral coatings and between adjacent reverse spiral coatings of the present invention in which the coating is staggered by half the width of the ribbon coating;

[0051] Figure 4 It is a schematic structural diagram of the coating device of the present invention;

[0052] Figure 5 It is a schematic diagram of the structure of a set of spiral coating mechanism and ultraviolet curing mechanism of the present invention;

[0053] Figure 6 It is a schematic radial cross-sectional view of the coated ring body of the present invention.

[0054] Description of the numbers in the figure:

[0055] 1. Copper wire; 2. Positive spiral coating; 3. Reverse spiral coating; 41. Spiral coating mechanism; 42. UV curing mechanism; 43. Positive coating assembly; 431. Positive synchronous gear; 44. Reverse coating assembly; 441. Reverse synchronous gear; 45. U-shaped bearing seat; 46. Coating ring; 461. Rack; 462. Gear; 463. Annular cavity; 47. Coating block; 471. Hollow cylinder; 472. Discharge port; 473. Feed port; 48. Drive motor; 49. Bevel gear. DETAILED DESCRIPTION

[0056] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0058] Example:

[0059] See also Figure 1-3 , a method for coating a corona-resistant enameled wire,

[0060] During the feeding process of the copper wire 1, a belt-shaped positive spiral coating 2 with a certain bandwidth is firstly coated by rotating around the copper wire in a clockwise direction, and then initially cured;

[0061] After the positive spiral coating 2 is formed, a belt-shaped reverse spiral coating 3 with a certain bandwidth is coated by rotating counterclockwise around the copper wire, and then preliminary curing is performed again to form a reverse spiral coating 3;

[0062] Repeatedly apply multiple layers alternately in front and back directions;

[0063] Carry out final curing;

[0064] The coating of one of the positive helical coating 2 and the reverse helical coating 3 comprises the following components: 50-60 parts by weight of epoxy resin, 3-5 parts by weight of silane coupling agent, 15-25 parts by weight of aluminum hydroxide, 5-10 parts by weight of phthalate plasticizer, 10-15 parts by weight of acid anhydride curing agent, and 1-3 parts by weight of hindered phenol antioxidant;

[0065] The coating of the other one comprises the following components: 40-50 parts by weight of polyimide resin, 10-20 parts by weight of nano-silicon dioxide, 5-10 parts by weight of graphene, 5-10 parts by weight of polyvinyl alcohol softener, 10-20 parts by weight of alicyclic amine curing agent, and 2-5 parts by weight of benzotriazole ultraviolet absorber.

[0066] Furthermore, the preliminary curing is performed by ultraviolet curing, and the UV intensity is set to 800 to 1200 mJ / cm 2 The final curing is performed by thermal curing, with the curing temperature set at 180°C to 220°C and the duration being 10 to 30 minutes.

[0067] Furthermore, the feeding speed of the copper wire 1 is set at 100 m / min to 500 m / min, and the rotation speed around the copper wire 1 is set at 300 to 1000 revolutions per minute.

[0068] Furthermore, the bandwidth of the positive helical coating 2 is the same as that of the reverse helical coating 3, and the pitch of the spirals of the positive helical coating 2 and the reverse helical coating 3 is the same as their bandwidth; adjacent positive helical coatings 2 and reverse helical coatings 3 are arranged crosswise; and two adjacent positive helical coatings 2 or two adjacent reverse helical coatings 3 are staggered by half the bandwidth.

[0069] The following is a table summarizing the test results of the enameled wire obtained by the coating method of the present invention and the existing mainstream enameled wire (Table 1).

[0070]

[0071]

[0072]

[0073] Table 1

[0074] Detailed description of test parameters and experimental prerequisites

[0075] The specific ingredients in the formula are:

[0076] The epoxy resin used is E-44 (bisphenol A type epoxy resin) produced by Jiangsu Yangnong Chemical Co., Ltd.:

[0077] The polyimide resin adopts SHPOLY series polyimide produced by Shanghai Hanke New Material Technology Co., Ltd.

[0078] Silane coupling agent: KH-550 and KH-151 series silane coupling agent produced by Nanjing Kaihua Chemical.

[0079] Aluminum hydroxide uses H-WF-10 (aluminum hydroxide micro powder) produced by Shandong Branch of China Aluminum Corporation;

[0080] The nano-silicon dioxide adopts the HT-200 series nano-silicon dioxide of Qingdao Hitech New Materials;

[0081] Graphene uses EGraph series graphene from Changzhou Sixth Element Materials Technology Co., Ltd.;

[0082] The polyvinyl alcohol softener adopts the HY-PAF polyvinyl alcohol series of Anhui Huayang New Materials Co., Ltd.

[0083] The phthalate plasticizer specifically used is the dibutyl phthalate (DBP) series products of Shandong Hailong Chemical;

[0084] The acid anhydride curing agent specifically adopts HET (hexahydrophthalic anhydride) of Jiangsu Haida Co., Ltd.

[0085] The hindered phenol antioxidant adopts the antioxidant 1010 (tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane) produced by Nantong Xingchen Synthetic Materials Co., Ltd.

[0086] The alicyclic amine curing agent used isophorone diamine (IPDA) from Shanghai Resin Factory;

[0087] The benzotriazole UV absorber uses the benzotriazole series UV absorber produced by Yangzhou Depu Chemical.

[0088] Test 1: Testing of high voltage motor coils

[0089] Purpose of the experiment: To verify the electrical insulation performance and mechanical strength of the new coating method under high voltage and high temperature environment, and to evaluate its service life.

[0090] Application scenario: high voltage motor coil;

[0091] Working environment: continuous high temperature (180℃), frequent mechanical shock;

[0092] Objective: To test the corona discharge voltage, mechanical strength and service life of enameled wire in this environment;

[0093] Experimental steps:

[0094] Copper wire preparation: Select copper wire with a diameter of 0.5mm and a length of 10 meters, clean and dry it.

[0095] Coating application:

[0096] Fix the copper wire on the coating device and apply the first layer of positive spiral coating in a clockwise direction. Set the coating speed to 600 rpm, the bandwidth to 1 mm, and the spiral pitch to be the same as the bandwidth.

[0097] Perform preliminary UV curing with UV intensity set to 1000mJ / cm 2 , lasting 2 minutes.

[0098] On the cured positive spiral coating, the reverse spiral coating is applied in a counterclockwise direction with the same parameter settings as the positive spiral coating, and preliminary curing is performed again.

[0099] Repeat the above process for a total of 4 layers, alternating between positive and negative layers to ensure even coverage.

[0100] Final curing: The coated copper wire was thermally cured in a constant temperature oven at 180°C for 20 minutes.

[0101] Corona discharge test: Place the coated enameled wire in a high-voltage tester, gradually increase the voltage, and record the critical voltage at which corona discharge occurs.

[0102] Mechanical strength test: Use a material testing machine to perform a tensile test and record the maximum tensile strength.

[0103] Service life test: Install the enameled wire into the simulated motor coil, continuously power it on for testing, and record the time until the coil fails.

[0104] Result analysis:

[0105] Experimental results show that the enameled wire prepared by this method has excellent electrical insulation performance and mechanical strength in a high-voltage, high-temperature environment, and its service life is significantly extended, making it suitable for use in high-demand electrical equipment.

[0106] Test 2: Testing in a high-speed rotating machinery environment

[0107] Purpose of the experiment: To evaluate the adaptability of the coating method in high-speed rotating machinery and to test its electrical performance, mechanical strength and service life.

[0108] Application scenarios: high-speed rotating mechanical equipment;

[0109] Working environment: high-speed rotation (10000rpm), drastic temperature changes (-20℃ to 150℃);

[0110] Objective: To test the pressure resistance and abrasion resistance of enameled wire in this environment;

[0111] Experimental steps:

[0112] Copper wire preparation: Use copper wire with a diameter of 0.4mm and a length of 8 meters, clean and dry it.

[0113] Coating application:

[0114] The copper wire feed speed was set to 400 m / min, and the coating was alternately performed in the same spiral coating manner, with a coating speed of 700 rpm and a bandwidth of 1.5 mm.

[0115] The initial curing after each coating is carried out with UV intensity of 1200mJ / cm 2 , lasting 2.5 minutes.

[0116] Final curing: Heat curing at 220°C for 30 minutes.

[0117] Withstand voltage test: simulate the working environment in high-speed rotating machinery, gradually apply voltage, and record the maximum withstand voltage value.

[0118] Wear test: Use a wear tester to apply a load of 5N for friction test and record the wear conditions.

[0119] Service life test: Continuously run the test in a mechanical simulator and record the time when the wire fails.

[0120] Result analysis:

[0121] The increase in coating thickness and the optimization of the coating process significantly improve the pressure resistance of the enameled wire in high-speed rotating machinery, but the cost is slightly increased, making it suitable for use in high-speed operating equipment.

[0122] Mainstream product 1 controlled trial

[0123] Application scenarios: conventional industrial equipment;

[0124] Working environment: moderate mechanical stress, temperature range is -10℃ to 100℃;

[0125] Objective: To verify the performance of common enameled wires on the market and compare them with the present invention;

[0126] Experimental steps:

[0127] Coating: According to the traditional coating method, one-way continuous coating, the coating thickness is controlled at 50μm.

[0128] Curing: UV curing and thermal curing, the parameters are consistent with the present invention.

[0129] test:

[0130] The parameters of corona discharge voltage, mechanical strength and service life tests are consistent with those of the present invention.

[0131] Result analysis:

[0132] Conventional products have average performance in terms of electrical insulation and mechanical strength, have a relatively short service life, and are prone to failure, especially in high-voltage environments. In contrast, the coating method of the present invention has significant performance improvements.

[0133] Through the above specific experimental steps, parameter settings and comparative analysis, the advantages of the present invention in terms of electrical insulation performance, mechanical strength and service life are clarified, especially in the application of high-voltage, high-temperature and high-speed rotating mechanical environments, showing great reliability and practical value. These test results prove the innovation and superiority of the coating method of the present invention.

[0134] Combination Figure 4-Figure 6 In a preferred embodiment of the present invention, the coating method is implemented by a coating device specially designed for the coating method; the coating device includes a plurality of spiral coating mechanisms 41 and an ultraviolet curing mechanism 42 arranged between two adjacent spiral coating mechanisms 41; the copper wire 1 is fed through the spiral coating mechanism 41 and the ultraviolet curing mechanism 42 in sequence; the spiral coating mechanism 41 includes a positive coating component 43 and a negative coating component 44; the positive coating component 43 and the negative coating component 44 respectively include a U-shaped bearing shoe 45 and a coating ring body 46 rollingly supported on the U-shaped bearing shoe 45; a coating block 47 in contact with the outer circumferential surface is arranged in the middle of the coating ring body 46; the length of the coating block 47 is equal to the width of the strip coating; the distance between the coating blocks 47 of the positive coating component 43 and the negative coating component 44 is an integer multiple of the width of the strip coating; the coating ring bodies 46 of the positive coating component 43 and the negative coating component 44 rotate in opposite directions and at the same speed.

[0135] In a preferred embodiment of the present invention, a rack 461 is provided on the outer circumferential surface of the coating ring body 46 along its circumference; the rack 461 is meshed with a gear 462 arranged outside the coating ring body 46; a driving motor 48 drives the gear 462 arranged above the coating ring body 46 to drive the coating ring body 46 to rotate; the positive coating component 43 and the negative coating component 44 also include a positive synchronous gear 431 and a negative synchronous gear 441 respectively; the positive synchronous gear 431 rotates coaxially with the gear 462 corresponding to the positive coating component 43; the negative synchronous gear 441 rotates coaxially with the gear 462 corresponding to the negative coating component 44; the positive synchronous gear 431 and the negative synchronous gear 441 are symmetrical and have a spacing; a bevel gear 49 is meshed with the positive synchronous gear 431 and the negative synchronous gear 441 at the same time to make the coating ring bodies 46 of the positive coating component 43 and the negative coating component 44 rotate synchronously and reversely.

[0136] In a preferred embodiment of the present invention, the coating ring body 46 is a hollow ring body having an annular cavity 463; the annular cavity 463 is filled with coating; the smearing block 47 is connected to the coating ring body 46 through a hollow cylinder 471; one end of the hollow cylinder 471 is detachably connected to the smearing block 47 and a discharge port 472 is provided on the side, and the other end penetrates into the annular cavity 463 and is connected to the outer inner wall of the annular cavity 463 and a feed port 473 is provided on the side; a small liquid pump is provided in the hollow cylinder 471 to assist the coating to flow to the side of the discharge port 472.

[0137] In a preferred embodiment of the present invention, there are multiple groups of smear blocks 47 disposed in the coating ring body 46, and the axial distance between two adjacent groups of smear blocks 47 is an integer multiple of the width of the strip coating.

[0138] In a preferred embodiment of the present invention, the coating method of the coating device is:

[0139] ① The copper wire 1 is fed at a uniform speed through the coating ring 46 and the ultraviolet curing mechanism 42 in sequence;

[0140] ② While the copper wire 1 is being fed, the driving motor 48 drives the gear 462 of the positive coating component 43 and the positive synchronous gear 431 to rotate, and the positive synchronous gear 431 drives the reverse synchronous gear 441 and the gear 462 of the reverse coating component 44 to rotate in the opposite direction through the bevel gear 49; the two gears 462 drive the two coating ring bodies 46 to rotate forward and reverse respectively; during the rotation process, the coating block 47 coats the surface of the copper wire 1, and a spiral coating is formed as the copper wire 1 is fed; as the coating ring body 46 rotates, the coating in the annular cavity 463 is squeezed between the inner and outer circles of the annular cavity 463 under the action of centrifugation, so that the coating enters the hollow cylinder 471 through the feed port 473 and flows out from the discharge port 472 to continuously replenish the coating for the coating block 47;

[0141] ③ Since there are multiple groups of coating blocks 47 in the coating ring body 46, and the axial distance between two adjacent groups of coating blocks 47 is an integer multiple of the bandwidth, multiple parallel-spaced positive spiral coatings 2 or reverse spiral coatings 3 can be coated simultaneously; the positive spiral coatings 2 or reverse spiral coatings 3 coated by two adjacent groups of spiral coating mechanisms 41 are staggered by half the bandwidth to ensure that no coating is missed;

[0142] ④ After each set of spiral coating mechanisms 41 completes one front and back coating, the copper wire 1 is initially cured by the ultraviolet curing mechanism 42 .

[0143] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and improved concepts of the present invention within the technical scope disclosed by the present invention, and they should be covered by the protection scope of the present invention.

Claims

1. A method for coating a corona-resistant enameled wire, characterized in that: During the feeding process of the copper wire (1), a ribbon-shaped positive spiral coating (2) is firstly coated around the copper wire in a clockwise rotation, and then initially cured; After the positive spiral coating (2) is formed, a strip-shaped reverse spiral coating (3) is coated by rotating the copper wire counterclockwise, and preliminary curing is performed again to form a reverse spiral coating (3); Repeatedly apply multiple layers alternately in front and back directions; Carry out final curing; The coating of one of the positive helical coating (2) and the reverse helical coating (3) comprises the following components: 50-60 parts by weight of epoxy resin, 3-5 parts by weight of silane coupling agent, 15-25 parts by weight of aluminum hydroxide, 5-10 parts by weight of phthalate plasticizer, 10-15 parts by weight of acid anhydride curing agent, and 1-3 parts by weight of hindered phenol antioxidant; The coating of another coating layer comprises the following components: 40-50 parts by weight of polyimide resin, 10-20 parts by weight of nano-silicon dioxide, 5-10 parts by weight of graphene, 5-10 parts by weight of polyvinyl alcohol softener, 10-20 parts by weight of alicyclic amine curing agent, and 2-5 parts by weight of benzotriazole ultraviolet absorber.

2. The coating method according to claim 1, characterized in that: The preliminary curing is performed by ultraviolet curing, and the UV intensity is set to 800 to 1200 mJ / cm².

3. The coating method according to claim 1, characterized in that: The final curing is performed by heat curing, with the curing temperature set at 180°C to 220°C and the duration being 10 to 30 minutes.

4. The coating method according to claim 1, characterized in that: The copper wire feeding speed is set at 100 m / min to 500 m / min, and the copper wire rotation speed is set at 300 to 1000 revolutions per minute.

5. The coating method according to claim 1, characterized in that: The band width, i.e., bandwidth, of the positive helical coating and the reverse helical coating is the same, and the pitch of the positive helical coating and the reverse helical coating is the same as their bandwidth; adjacent positive helical coatings and reverse helical coatings are arranged crosswise; two adjacent positive helical coatings or two adjacent reverse helical coatings are arranged staggered by half the bandwidth.

6. The coating method according to any one of claims 1 to 5, characterized in that: The coating method is implemented by a coating device; the coating device comprises a plurality of groups of spiral coating mechanisms (41) and an ultraviolet curing mechanism (42) arranged between two adjacent groups of spiral coating mechanisms (41); the copper wire (1) passes through the spiral coating mechanisms (41) and the ultraviolet curing mechanism (42) in sequence; the spiral coating mechanism (41) comprises a positive coating component (43) and a negative coating component (44); the positive coating component (43) and the negative coating component (44) each comprise a U-shaped bearing shoe seat (45) and a coating ring body (46) rollingly supported on the U-shaped bearing shoe seat (45); a coating block (47) in contact with the outer circumferential surface is arranged in the middle of the coating ring body (46); the length of the coating block (47) is equal to the bandwidth; the distance between the coating blocks (47) of the positive coating component (43) and the negative coating component (44) is an integer multiple of the bandwidth; the coating ring bodies (46) of the positive coating component (43) and the negative coating component (44) rotate in opposite directions and at the same speed.

7. The coating method according to claim 6, characterized in that: A rack (461) is provided on the outer circumferential surface of the coating ring body (46) along its circumference; the rack (461) meshes with a gear (462) provided outside the coating ring body (46); a drive motor (48) drives the gear (462) provided above the coating ring body (46) to drive the coating ring body (46) to rotate; the positive coating assembly (43) and the negative coating assembly (44) further include a positive synchronous gear (431) and a negative synchronous gear (441), respectively; the positive synchronous gear (4 31) rotates coaxially with the gear (462) corresponding to the positive coating component (43); the reverse synchronous gear (441) rotates coaxially with the gear (462) corresponding to the reverse coating component (44); the positive synchronous gear (431) and the reverse synchronous gear (441) are symmetrical and have a spacing; a bevel gear (49) is simultaneously engaged with the positive synchronous gear (431) and the reverse synchronous gear (441) to enable the coating ring bodies (46) of the positive coating component (43) and the reverse coating component (44) to rotate synchronously in opposite directions.

8. The coating method according to claim 6, characterized in that: The coating ring body (46) is a hollow ring body having an annular cavity (463); the annular cavity (463) is filled with coating; the coating block (47) is connected to the coating ring body (46) via a hollow cylinder (471); one end of the hollow cylinder (471) is detachably connected to the coating block (47) and has a discharge port (472) on the side, while the other end penetrates into the annular cavity (463) and is connected to the outer inner wall of the annular cavity (463) and has a feed port (473) on the side; a small liquid pump is arranged in the hollow cylinder (471) to assist the coating to flow toward the discharge port (472).

9. The coating method according to claim 6, characterized in that: There are multiple groups of smear blocks (47) arranged in the coating ring body (46), and the distance between two adjacent groups of smear blocks (47) along the axial direction is an integer multiple of the bandwidth.

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