Low-loss inductor and manufacturing method thereof

Abstract

The invention discloses a low-loss inductor and a manufacturing method thereof, the low-loss inductor comprises a magnetic core and a copper wire wound on the magnetic core and used for realizing current conduction, two ends of the copper wire form bevel electrodes at bevel positions of the outer side of the magnetic core, and the surface of the copper wire is coated with a paint film used for realizing insulation protection. Ink layers used for insulation and protection are arranged on the magnetic core and the copper wires. The magnetic core is prepared from low-loss formula powder formed by mixing 3-6 [mu] m ferro-nickel alloy (FeNi) powder and a nanocrystalline seed material according to the mass ratio of 4: 6 and coating the mixture with epoxy glue, traditional magnetic materials such as FeSiCr and carbonyl iron powder are replaced, and meanwhile, a silver-plated enameled copper wire formed by plating a copper wire body with a 2-5 [mu] m silver layer and a polyurethane / polyester imine paint film is matched; the magnetic hysteresis loss and the air gap loss of the magnetic core are reduced, the series resistance (Rs) of the copper wire is reduced, finally, the volume loss (Pcv) of the inductor is reduced by 20%-60% compared with a traditional integrally-formed inductor, and the requirements of high-power-density hardware in AI, HPC and other scenes for low loss of power management are met.

Description

Technical Field

[0001] This invention relates to the field of inductor manufacturing technology, and more specifically, to a low-loss inductor and a method for manufacturing the same. Background Technology

[0002] In recent years, artificial intelligence (AI), high-performance computing (HPC), big data storage and edge computing technologies have developed rapidly, putting extreme demands on the performance of computing hardware. GPUs and CPUs, as the core of computing power, have continuously improved their processing speed and energy efficiency, but this has brought the challenge of soaring power consumption. In AI training, inference and large-scale data storage scenarios, hardware power density has increased dramatically, significantly increasing the efficiency requirements of power management systems.

[0003] In the existing technology, the integral molded inductor is a key component of the power management system. Its manufacturing method is as follows: copper wire (round wire or flat wire) is wound on a mold or a skeleton with silicon chromium iron alloy or carbonyl iron powder as the base material, and then formed by cold pressing or hot pressing process. The materials used in the forming process are also silicon chromium iron alloy or carbonyl iron powder.

[0004] However, existing technologies for integrally molded inductors have certain problems. On the one hand, regarding the core material, the commonly used conventional magnetic powders (such as carbonyl iron powder) inherently have high core losses (including hysteresis losses and eddy current losses), especially under high-frequency switching conditions. This leads to significant temperature rise and a decrease in the quality factor of the inductor, which not only directly increases system energy consumption but also becomes a problem for improving switching frequency and power density. On the other hand, regarding the conductor structure, the internal windings usually use conventional copper wire, whose large series resistance (Rs) causes significant DC and AC losses (especially under the influence of high-frequency skin effect and proximity effect), further reducing the energy conversion efficiency of the inductor and generating additional heat. The high loss of the magnetic material and the high resistance of the winding conductors are superimposed, reducing the overall efficiency of the power management system and affecting its application in advanced electronic devices such as high-end computing chips and communication base stations. Therefore, we urgently need a low-loss inductor and its manufacturing method to solve the above problems. Summary of the Invention

[0005] One objective of this invention is to provide a new technology solution for a low-loss inductor and its manufacturing method. By using 3-6μm FeNi powder and nanocrystal seeds in a 4:6 ratio to form a magnetic core, and copper wires plated with a 2-5μm silver layer to form copper wires, and with appropriate processes, the inductor Rs and magnet losses are reduced, thus meeting the requirements of high power density hardware.

[0006] According to a first aspect of the present invention, a low-loss inductor is provided, comprising a magnetic core and a copper wire wound on the magnetic core for current conduction, wherein the two ends of the copper wire form corner electrodes at the bends on the outside of the magnetic core, the surface of the copper wire is coated with a varnish film for insulating protection, the magnetic core and the copper wire are provided with an ink layer for insulation and protection, and the copper wire is provided with an electrode plating layer at the corner electrodes.

[0007] Optionally, the magnetic core is a mixture of nickel-iron alloy, nanocrystalline seed material, and epoxy adhesive.

[0008] Optionally, the copper conductor body of the copper wire is plated with a silver layer, and the varnish film is located outside the silver layer. The varnish film is made of polyurethane varnish film or polyesterimide varnish film.

[0009] Optionally, the ink layer is made of insulating ink.

[0010] Optionally, the electrode plating layer is composed of a copper layer, a nickel layer and a tin layer in sequence, with the copper layer located on the surface of the angled electrode, the nickel layer covering the outside of the copper layer, and the tin layer covering the outside of the nickel layer.

[0011] A method for manufacturing a low-loss inductor, for manufacturing the low-loss inductor according to any one of claims 1-5, characterized in that it includes the following steps: Optionally, powder preparation: Weigh nickel-iron alloy powder with a particle size of 3~6μm and nano-crystal seed material at a mass ratio of 4:6, put them into a mixing device and stir until uniform, add a preset amount of epoxy adhesive to the mixed powder, and continue stirring until the epoxy adhesive uniformly coats the surface of the powder. The coated material is first baked and granulated, then cooled and baked and granulated a second time to obtain a low-loss formula powder.

[0012] Optionally, core prefabrication: The low-loss formula powder obtained in S1 is placed into the corresponding prefabrication molds of type T, type E, type I and type R, and pressed into shape under specific pressure to obtain pre-formed magnetic cores.

[0013] Optionally, the winding process involves using silver-plated enameled copper wire, which is tightly wound onto the outer surface of the pre-formed magnetic core obtained in S2 according to the number of turns required by the coil drawing. The ends of the copper wire are then bent two or more times using a bending device to form bent electrodes, thus obtaining a semi-finished inductor. The structure of the silver-plated enameled copper wire is consistent with that of the copper wire described above.

[0014] Optionally, the inductor semi-finished product obtained in S3 can be implanted into the molding cavity and integrally formed by cold pressing or hot pressing.

[0015] Optionally, the inductor semi-finished product formed in S4 is placed in a baking oven and baked in the following order: 70°C for 20 minutes, 90°C for 20 minutes, 120°C for 20 minutes, and 160°C for 1 hour.

[0016] Optionally, the baked inductor semi-finished product in S5 is fixed on a grinding device and the burrs on the surface of the inductor semi-finished product are removed by grinding.

[0017] Optionally, the inductor semi-finished product after grinding in S6 is placed in a chamfering device to chamfer the sharp edges and corners of the inductor semi-finished product.

[0018] Optionally, the inductor semi-finished product after chamfering in S7 is surface-impregnated and preheated. After preheating, it is placed in a roller and then the insulating ink is sprayed onto the outer surface of the inductor semi-finished product by thermal spraying, leaving only the folded electrodes exposed. After spraying, the product is placed in an environment of 180-220℃ and kept at that temperature for 120 minutes to allow the ink to cure and form an ink layer.

[0019] Optionally, laser and electroplating: using laser equipment to laser treat the surface of the corner electrode of the inductor semi-finished product after spraying in S8 to remove the paint film and insulating material on the surface of the corner electrode; The product is placed in an electroplating bath, and copper, nickel, and tin layers are electroplated sequentially to form an electrode plating layer on the surface, thus producing a low-loss inductor.

[0020] Optionally, in step S4, the molding parameters of the inductor semi-finished product are: molding temperature range of 25-180℃, holding time range of 10-120S, and molding pressure range of 300-1000MPa.

[0021] Optionally, in step S6, the grinding parameters set for the grinding equipment are: a grinding speed range of 300-1300 r / min and a single cutting depth range of 0.02-0.08 mm.

[0022] Optionally, in step S7, the chamfering parameters of the chamfering device are: chamfering speed range of 15-25 r / min and chamfering time range of 1-10 min.

[0023] Optionally, in step S8, the preheating temperature range of the impregnated inductor semi-finished product is 100-150℃, the heat preservation time range is 10-30min; the rotation speed range of the roller is 8-12r / min; the parameters of thermal spraying are: the spray gun distance range is 13-15cm, the spray gun nozzle diameter range is 0.3-0.5mm, and the spray gun air pressure range is 0.1-0.3Mpa.

[0024] 1. According to one embodiment of this disclosure, the low-loss inductor and its manufacturing method use a low-loss formula powder to prepare the magnetic core by mixing 3~6μm nickel-iron alloy (FeNi) powder and nanocrystalline seed material in a 4:6 mass ratio and coating with epoxy adhesive. This replaces traditional magnetic materials such as FeSiCr and carbonyl iron powder. At the same time, it is combined with silver-plated enameled copper wire with a 2-5μm silver layer and polyurethane / polyesterimide varnish film on the copper wire body. This reduces the hysteresis loss and air gap loss of the magnetic core and the series resistance (Rs) of the copper wire. Ultimately, the volume loss (Pcv) of the inductor is reduced by 20% to 60% compared with traditional integral molded inductors, which is suitable for the low power loss requirements of high power density hardware in AI, HPC and other scenarios.

[0025] 2. According to one embodiment of this disclosure, the low-loss inductor and its manufacturing method ensure that the core powder and copper wire coating are fully cured without cracking through a four-temperature-phase baking process (70℃ / 20min→90℃ / 20min→120℃ / 20min→160℃ / 1h); the dimensional accuracy and edge integrity of the product are ensured by the regionally controlled grinding process (low speed and shallow cutting in the core area, and high speed and deep cutting in the copper wire transition area) and chamfering process (low speed and long time for complex cores, and high speed and short time for simple cores); the thermal spraying ink process that exposes only the corner electrodes achieves precise insulation protection, while laser treatment and layered electroplating (copper layer → nickel layer → tin layer) ensure the stability of electrode conductivity. Ultimately, while improving the structural reliability of the inductor, the low-loss performance and long-term stability are further enhanced.

[0026] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0027] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0028] Figure 1 A flowchart of a method for manufacturing a low-loss inductor in one embodiment; Figure 2 This is a schematic diagram of the T-shaped magnetic core and copper wire structure of a low-loss inductor and its manufacturing method in one embodiment. Figure 3 This is a schematic diagram of the E-type magnetic core and copper wire structure of a low-loss inductor and its manufacturing method in one embodiment. Figure 4 This is a schematic cross-sectional view of the copper wire structure of a low-loss inductor and its manufacturing method in one embodiment. Figure 5 This is a schematic diagram of the angled electrode structure of a low-loss inductor and its manufacturing method in one embodiment.

[0029] The following are labeled in the diagram: 1. Magnetic core; 2. Copper wire; 3. Angular electrode; 4. Paint film; 5. Ink layer; 6. Electrode plating layer; 61. Copper layer; 62. Nickel layer; 63. Tin layer; 7. Silver layer. Detailed Implementation

[0030] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0031] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0032] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0033] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0034] like Figure 1-5 As shown, a low-loss inductor includes a magnetic core 1 and a copper wire 2 wound on the magnetic core 1 for current conduction. The magnetic core 1 is a composite material composed of nickel-iron alloy, nanocrystalline seed material and epoxy adhesive. The copper conductor body of the copper wire 2 is plated with a silver layer 7.

[0035] Here, the magnetic core 1 and the copper wire 2 are tightly spirally wound: this ensures that the magnetic field is concentrated inside the magnetic core 1, reduces leakage magnetic loss, and at the same time improves the stability of the inductance of the inductor, avoiding performance fluctuations caused by loose winding.

[0036] Furthermore, the magnetic core 1 is a mixture of nickel-iron alloy, nanocrystalline seed material, and epoxy adhesive. The nickel-iron alloy exists as powder with a particle size of 3-6 μm, the nanocrystalline seed material is uniformly dispersed in the nickel-iron alloy powder as nano-sized particles, and the epoxy adhesive is physically coated onto the surface of the mixed powder. After mixing, baking, granulation, and pressing, the three components form a dense magnetic core 1. The core 1 has no obvious voids or cracks inside, and its density is controlled at 6.5-7.2 g / cm³. 3 Within the range.

[0037] It is important to note that nickel-iron alloys possess high permeability and low hysteresis loss characteristics, which can effectively reduce the magnetic loss of inductors and are suitable for high-frequency applications. Nanocrystalline seed materials can refine the grain structure of magnetic core 1, improve the uniformity of magnetic properties of magnetic core 1, and avoid excessive local losses caused by coarse grains. Epoxy adhesive coating can enhance the bonding force between mixed powders, giving magnetic core 1 good mechanical strength, resisting the external forces of molding, grinding and other processes, while reducing the risk of pulverization of magnetic core 1 during use.

[0038] Furthermore, the internal density setting of the magnetic core 1 can further reduce the internal air gap of the magnetic core 1, reduce air gap loss, and at the same time improve the thermal conductivity of the magnetic core 1, making it easier for the inductor to dissipate heat during operation.

[0039] The copper wire 2 has a copper conductor body plated with a silver layer 7, the thickness of which is 2-5 μm. The silver layer 7 is uniformly covered on the outer surface of the copper conductor body by electroplating. The purity of the silver layer 7 is ≥99.9%, and it is free of pinholes and blistering defects. The varnish film 4 is located outside the silver layer 7. The varnish film 4 has a thickness of 5-10 μm and is formed by coating and curing. The varnish film 4 is made of polyurethane varnish film 4 or polyesterimide varnish film 4. Its temperature resistance is ≥155℃, its voltage resistance is ≥80Vdc, and it has good solvent resistance and wear resistance.

[0040] Here, the enamel film 4 provides reliable insulation between the copper wires 2, preventing short circuits between adjacent wires, while also withstanding temperature changes during the manufacturing and use of the inductor to avoid insulation failure.

[0041] Furthermore, the resistivity of silver in the silver layer 7 is much lower than that of copper, which can significantly reduce the series resistance (Rs) of the copper wire 2 and reduce Joule losses during current conduction; at the same time, silver has excellent oxidation resistance, which prevents the increase in resistance caused by oxidation of the surface of the copper wire 2.

[0042] Furthermore, the polyurethane or polyesterimide coating 4 used in the coating film 4 has a temperature resistance rating of ≥155℃, which can withstand the high temperature environment during the baking, molding and use of the inductor, and prevent the coating film 4 from aging and peeling off; the withstand voltage is ≥80Vdc, ensuring the reliability of insulation between the copper wires 2; the solvent resistance and abrasion resistance ensure that the coating film 4 is not damaged in subsequent spraying and grinding processes.

[0043] The magnetic core 1 and copper wire 2 are provided with an ink layer 5 for insulation and protection. The ink layer 5 is made of insulating ink, which is based on epoxy resin and contains curing agents, fillers and other components. It is applied to the surface of the magnetic core 1 and copper wire 2 by thermal spraying. The thickness of the ink layer 5 after curing is 8-15μm, the hardness is ≥HB, the breakdown voltage is ≥200Vdc and it has good resistance to damp heat.

[0044] Here, the partial coating of ink layer 5 provides physical protection for the magnetic core 1 and copper wire 2, isolating them from external dust and moisture corrosion, and through the design of exposing only the corner electrode 3, it does not affect the conductivity of the electrode.

[0045] Here, the epoxy resin-based insulating ink has excellent insulation properties, with a breakdown voltage of ≥200Vdc, effectively isolating the external environment from internal components and preventing leakage risks; at the same time, the strong adhesion of epoxy resin ensures that the ink layer 5 is tightly bonded to the surface of the magnetic core 1 and copper wire 2, and is not easy to fall off.

[0046] Furthermore, the thickness in the range of 8-15μm provides sufficient protection for internal components while avoiding an increase in inductor volume due to excessive ink layer 5; the hardness ≥HB can withstand minor mechanical impacts, reducing damage to the paint film 4 during use; its resistance to damp heat ensures that the inductor can still work stably in humid environments, improving the product's environmental adaptability and extending its service life.

[0047] At the two ends of the copper wire 2, corner electrodes 3 are formed at the bends on the outside of the magnetic core 1. A useful electrode electroplating layer 6 is disposed on the copper wire 2 at the corner electrode 3. The electrode electroplating layer 6 is composed of a copper layer 61, a nickel layer 62, and a tin layer 63 in sequence. Each layer is formed by electroplating, and the interlayer bonding force is ≥5N / cm. The copper layer 61 is located on the surface of the corner electrode 3 and has a thickness of 3-8μm to ensure a tight bond with the corner electrode 3. The nickel layer 62 covers the outside of the copper layer 61 and has a thickness of 2-5μm to prevent copper ion migration. The tin layer 63 covers the outside of the nickel layer 62 and has a thickness of 1-3μm, providing good solderability.

[0048] Here, the angled electrode 3 can avoid poor conductive contact caused by dispersion and deformation at the end of the wire, providing a flat and continuous adhesion substrate for the subsequent electrode electroplating layer 6, and ensuring the conductivity of the electrode.

[0049] Furthermore, an electroplating layer is formed only in the area of ​​the angled electrode 3, which precisely improves the conductivity and oxidation resistance of the electrode and avoids unnecessary material waste.

[0050] It is important to note that the bottom copper layer 61 is made of the same material as the copper conductor of the angle electrode 3, ensuring good compatibility and strong adhesion, thus preventing the electroplated layer from peeling off and further reducing the contact resistance of the electrode. The middle nickel layer 62 effectively prevents copper ions in the copper layer 61 from migrating to the surface, avoiding the impact of copper ions on the soldering performance of the tin layer 63. At the same time, nickel has excellent corrosion resistance, improving the environmental tolerance of the electrode. The tin in the surface tin layer 63 has a low melting point and good soldering wettability, facilitating the soldering connection between the inductor and the external circuit, reducing the risk of poor soldering. In addition, the surface of the tin layer 63 is smooth, which can reduce the contact resistance after soldering.

[0051] A method for manufacturing a low-loss inductor includes the following steps: S1: Powder mixing: Weigh nickel-iron alloy powder with a particle size of 3~6μm and nano-crystal seed material at a mass ratio of 4:6, put them into a mixing device and stir until uniform. Add the preset amount of epoxy adhesive to the mixed powder and continue stirring until the epoxy adhesive uniformly coats the surface of the powder. The coated material is first baked and granulated, then cooled and baked and granulated a second time to obtain a low-loss formula powder. Here, nickel-iron alloy powder with a particle size of 3-6 μm and nanocrystalline seed material are weighed at a mass ratio of 4:6 and placed in a high-speed mixer (speed 800-1200 r / min) and stirred for 30-60 min until uniform; a preset amount of epoxy adhesive (the amount of adhesive added is 3%-5% of the mass of the mixed powder) is added to the mixed powder, and stirring is continued at a speed of 500-800 r / min for 20-30 min to ensure that the epoxy adhesive uniformly coats the surface of the powder; the coated material is placed in a granulator and baked and granulated for the first time at a temperature of 80-100℃ to obtain primary granules; after the primary granules have cooled to room temperature, they are placed in the granulator again and baked and granulated for the second time at a temperature of 100-120℃ to obtain a low-loss formulation powder with a particle size of 50-100 μm; S2: Pre-forming of magnetic core 1: The low-loss formula powder obtained in S1 is placed into the corresponding pre-forming molds of type T, type E, type I and type R, and cold-pressed under a pressure of 200-500MPa for a holding time of 20-30S to obtain a pre-formed magnetic core 1 with uniform density and regular shape. S3: Winding: Using silver-plated enameled copper wire 2, according to the number of turns required by the coil drawing (e.g., 5-20 turns), the silver-plated enameled copper wire 2 is tightly wound onto the outer surface of the pre-formed magnetic core 1 obtained in S2 using an automatic winding machine (winding tension 5-10N), ensuring that the coil is not loose or overlapping; the two ends of the copper wire 2 are bent twice or more using a bending machine, with the bending angle controlled between 90°-135°, forming the bent electrode 3, and obtaining the inductor semi-finished product; the structure of the silver-plated enameled copper wire 2 is the same as that of the copper wire 2 described above; S4: Molding: The inductor semi-finished product obtained in S3 is inserted into the molding cavity, and the whole product is formed by selecting cold pressing or hot pressing process. The molding parameters for the inductor semi-finished product are as follows: molding temperature range is 25-180℃, holding time range is 10-120s, and molding pressure range is 300-1000MPa. Here, when using the cold pressing process, the forming temperature is 25-50℃, the holding time is 60-120S, and the forming pressure is 800-1000MPa, which is suitable for the magnetic core 1 material that is sensitive to high temperature; when using the hot pressing process, the forming temperature is 120-180℃, the holding time is 10-30S, and the forming pressure is 300-600MPa. In addition, nitrogen gas with a purity of ≥99.9% is introduced during the hot pressing process to prevent the silver layer 7 on the surface of the copper wire 2 from oxidizing.

[0052] S5: Baking: Place the semi-finished inductor formed in S4 into a hot air circulating baking oven and bake in a stepped heating sequence of 70℃ for 20 minutes, 90℃ for 20 minutes, 120℃ for 20 minutes, and 160℃ for 1 hour to avoid sudden temperature rise that could cause the magnetic core 1 to crack or the paint film 4 to peel off. S6: Grinding: Fix the baked inductor semi-finished product from S5 onto a CNC grinding machine, and remove burrs and excess material from the surface of the inductor semi-finished product by grinding with a grinding wheel to ensure that the product's external dimensions meet the design tolerance (±0.05mm). The grinding parameters set for the grinding equipment are: grinding speed range of 300-1300 r / min, and single cutting depth range of 0.02-0.08 mm; Here, for the magnetic core 1 area, the grinding speed is 300-600 r / min, and the single cutting depth is 0.02-0.04 mm to avoid the magnetic core 1 from cracking; for the transition area between the copper wire 2 and the angled electrode 3, the grinding speed is 800-1300 r / min, and the single cutting depth is 0.05-0.08 mm to quickly remove burrs without damaging the paint film 4; S7: Chamfering: Place the inductor semi-finished product ground in S6 into a roller chamfering machine, add special abrasive (such as alumina abrasive), and perform rounded transition treatment on the sharp edges and corners of the inductor semi-finished product. The radius of the rounded corner is controlled between 0.1 and 0.3 mm. In step S7, the chamfering parameters of the chamfering equipment are: chamfering speed range of 15-25 r / min and chamfering time range of 1-10 min; Here, for T-type and E-type magnetic cores 1, the chamfering speed is 15-20 r / min and the chamfering time is 5-10 min to ensure that complex edges and corners are fully chamfered; for I-type and R-type magnetic cores 1, the chamfering speed is 20-25 r / min and the chamfering time is 1-5 min to balance the chamfering effect and production efficiency.

[0053] S8: Spraying: The inductor semi-finished product after chamfering in S7 is wiped and impregnated with alcohol (to remove surface oil and dust); then it is placed in a preheating oven for preheating. After preheating, it is transferred to the roller of the roller spraying equipment (the roller rotates at a constant speed); the insulating ink is sprayed onto the outer surface of the inductor semi-finished product by thermal spraying using an automatic spray gun, and the corner electrode 3 is exposed by a special mold; after spraying, the product is placed in a curing oven and kept at 180-220℃ for 120 minutes to allow the ink to fully cure and form a dense ink layer 5. The thickness of the ink layer 5 after curing is 8-15μm. In step S8, the preheating temperature range of the impregnated inductor semi-finished product is 100-150℃, and the heat preservation time ranges from 10 to 30 minutes; the rotation speed range of the roller is 8-12 r / min; the parameters of thermal spraying are: spray gun distance range is 13-15 cm, spray gun nozzle diameter range is 0.3-0.5 mm, and spray gun air pressure range is 0.1-0.3 MPa. Here, when the ambient temperature is below 25℃, the preheating temperature is 130-150℃, and the holding time is 20-30 minutes; when the ambient temperature is above 25℃, the preheating temperature is 100-130℃, and the holding time is 10-20 minutes; the rotation speed of the roller is 8-12 r / min to ensure uniform tumbling of the product; the parameters for thermal spraying are: spray gun distance range of 13-15cm, spray gun nozzle diameter range of 0.3-0.5mm, and spray gun air pressure range of 0.1-0.3Mpa; specifically, when spraying the magnetic core 1 area, the spray gun distance is 14-15cm, the nozzle diameter is 0.4-0.5mm, and the air pressure is 0.2-0.3Mpa; when spraying the copper wire 2 area, the spray gun distance is 13-14cm, the nozzle diameter is 0.3-0.4mm, and the air pressure is 0.1-0.2Mpa.

[0054] S9: Laser and Electroplating: Using a fiber laser machine (laser power 10-20W), the surface of the corner electrode 3 of the inductor semi-finished product after spraying in S8 is laser-treated to remove the paint film 4 and insulating material from the surface of the corner electrode 3, exposing the clean copper conductor body; the product is then placed in the electroplating tank of the electroplating production line for copper electroplating (current density 1-2A / dm³). 2 Nickel plating (current density 0.5~1A / dm³) 2 ), tin plating (current density 1~1.5A / dm³) 2 An electrode plating layer 6 is formed on the surface of the angled electrode 3; after electroplating, it is cleaned with pure water (cleaning time 5-10 min) and dried with hot air (temperature 80-100℃) to obtain a low-loss inductor.

[0055] Embodiment 1 of the present invention: A1: Powder formulation: Weigh nickel-iron alloy powder with a particle size of 3~6μm and nano-crystal seed material at a mass ratio of 4:6, mix evenly, add epoxy glue for coating, and then bake and granulate for the first time, cool, and bake and granulate for the second time to obtain low loss formula powder.

[0056] A2: Pre-fabrication of magnetic core 1: The low-loss formula powder is placed into a T-shaped pre-fabrication mold and pressed into shape to obtain T-shaped pre-formed magnetic core 1. A3: Winding: Silver-plated enameled copper wire 2 is used. The copper wire body is plated with a 2-5μm silver layer 7. The silver layer 7 is covered with a polyurethane varnish film 4 with a withstand voltage of 80Vdc or higher. It is tightly wound on the outer surface of the T-shaped pre-formed magnetic core 1 according to the number of turns required by the drawing. The two ends of the copper wire 2 are bent twice using a bending device to form bent electrodes 3, thus obtaining the inductor semi-finished product.

[0057] A4: Molding: Place the semi-finished product into the molding cavity and use hot pressing process to form it. Molding parameters: 150℃, holding pressure for 120s, molding pressure 800MPa. A5: Baking: Place the semi-finished product from step 3 in a baking oven and set four temperature levels: 70, 90, 120, and 160℃. Bake for 20 minutes, 20 minutes, 20 minutes, and 1 hour respectively.

[0058] A6: Grinding: Set the grinding speed to 400r / min and the single cutting depth to 0.05mm to grind and remove surface burrs; A7: Chamfering: Set chamfering speed to 20r / min and chamfering time to 5min to handle sharp edges and corners; A8: Spraying: Wet the surface of the semi-finished product, preheat to 120℃ and keep warm for 20 minutes, and put it into a roller with a rotation speed of 10 r / min; spray insulating ink at a spray gun distance of 14 cm, nozzle diameter of 0.4 mm and air pressure of 0.2 MPa, leaving only the corner electrode 3 exposed; after spraying, put it in an environment of 200℃ and keep warm for 120 minutes to allow the ink to cure and form an ink layer 5; A9: Laser and electroplating: The polyurethane coating 4 on the surface of the angled electrode 3 is removed by laser. The product is then placed in an electroplating tank and a copper layer 61, a nickel layer 62, and a tin layer 63 are electroplated in sequence to form the electrode electroplating layer 6, thus producing a T-type low-loss inductor.

[0059] Embodiment 2 of the present invention: B1: Powder formulation: Weigh nickel-iron alloy powder with a particle size of 3~6μm and nano-crystal seed material at a mass ratio of 4:6, mix evenly, add epoxy glue for coating, and then bake and granulate for the first time, cool, and bake and granulate for the second time to obtain low loss formula powder.

[0060] B2: Pre-forming of magnetic core 1: The low-loss formula powder is placed into the E-type pre-forming mold and pressed to form the E-type pre-formed magnetic core 1.

[0061] B3: Winding: Silver-plated enameled copper wire 2 is used. The copper wire body is plated with a 2-5μm silver layer 7. The silver layer 7 is covered with a polyurethane varnish film 4 with a withstand voltage of 80Vdc or higher. It is tightly wound on the outer surface of the E-type pre-formed magnetic core 1 according to the number of turns required by the drawing. The two ends of the copper wire 2 are bent twice using a bending device to form bent electrodes 3, thus obtaining the inductor semi-finished product.

[0062] B4: Molding: Hot pressing process is used for molding. Molding parameters: 150℃, holding pressure for 120s, molding pressure 900MPa. B5: Baking: Place the semi-finished product from step 3 in a baking oven and set four temperature levels: 70, 90, 120, and 160℃. Bake for 20 minutes, 20 minutes, 20 minutes, and 1 hour respectively.

[0063] B6: Grinding: Set the grinding speed to 500r / min and the single cutting depth to 0.05mm to grind the baked semi-finished product; B7: Chamfering: Set chamfering speed to 20r / min and chamfering time to 5min to handle sharp edges and corners; B8: Spraying: Wet the surface of the semi-finished product, preheat to 120℃ and keep warm for 20 minutes, then place it in a roller with a rotation speed of 10 r / min; spray insulating ink at a spray gun distance of 14 cm, nozzle diameter of 0.4 mm, and air pressure of 0.2 MPa, leaving only the corner electrode 3 exposed; after spraying, place the product in an environment of 210℃ and keep warm for 120 minutes to allow the ink to cure; B9: Laser and electroplating: The polyurethane coating 4 on the surface of the angled electrode 3 is removed by laser. The product is then placed in an electroplating tank and copper layer 61, nickel layer 62, and tin layer 63 are electroplated in sequence to form electrode electroplating layer 6, thus producing an E-type low-loss inductor.

[0064] When using conventional enameled copper wire 2: C1: Winding: A certain number of turns of conventional enameled copper wire 2 are wound onto the surface of a pre-formed T-shaped, E-shaped, I-shaped, R-shaped, or other magnetic core 1 according to the installation drawings. The surface of this conventional temperature-resistant copper wire 2 is coated with an organic coating, 5-10 μm thick, with a withstand voltage of over 80 Vdc. The magnetic core 1 uses alloy materials such as carbonyl iron powder, FeSi, FeSiCr, amorphous nanocrystalline magnetic materials, etc.

[0065] C2: Molding: The semi-finished product from step 1 is inserted into the mold cavity and formed using a hot pressing process. Molding temperature: 150℃, holding time: 90s, molding pressure: 800MPa; C3: Curing: Place the semi-finished product from step 2 in an oven for curing. Curing temperature: 180℃, holding time: 2 hours.

[0066] C4: Grinding: Grinding speed: 400r / min, single cut depth: 0.05mm; C5: Chamfering: Chamfering speed: 20 rpm, Chamfering time: 5 min C6: Spraying: After the above beveling, the product surface is first impregnated, and then the ink is sprayed onto the product surface using thermal spraying. The surface paint is then cured by baking. The product is first preheated to 120℃ for 20 minutes, and then placed in a roller. The roller speed is 10 rpm / min, the spray gun distance is 15 cm, the spray gun nozzle diameter is 0.5 mm, and the spray gun air pressure is 0.3 MPa. The curing conditions for the product after roller spraying are 180℃ for 120 minutes. C7: Other: After spraying, the product undergoes laser and electroplating processes to form the final inductor product.

[0067] The inductor Rs and loss performance of Examples 1 and 2, and those using conventional enameled copper wire 2 with the same package and inductance value, are shown in the table below: ; As can be seen from the data in the table, the Rs and losses of the inductor obtained by the present invention are significantly lower than those of the traditional integral molded inductor, with losses typically being 20% ​​to 60% lower.

[0068] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A low-loss inductor, characterized in that: It includes a magnetic core (1) and a copper wire (2) wound on the magnetic core (1) for current conduction. The two ends of the copper wire (2) form corner electrodes (3) at the corners on the outside of the magnetic core (1). The surface of the copper wire (2) is coated with a varnish film (4) for insulation protection. The magnetic core (1) and the copper wire (2) are provided with an ink layer (5) for insulation and protection. The copper wire (2) is provided with an electrode electroplating layer (6) at the corner electrode (3).

2. The low-loss inductor according to claim 1, characterized in that: The magnetic core (1) is a mixture of nickel-iron alloy, nanocrystalline seed material and epoxy adhesive.

3. A low-loss inductor according to claim 1, characterized in that: The copper wire body of the copper wire (2) is plated with a silver layer (7), and the lacquer film (4) is located outside the silver layer (7). The material of the lacquer film (4) is a polyurethane lacquer film or a polyesterimide lacquer film.

4. A low-loss inductor according to claim 1, characterized in that: The ink layer (5) is made of insulating ink.

5. A low-loss inductor according to claim 1, characterized in that: The electrode electroplating layer (6) is composed of a copper layer (61), a nickel layer (62) and a tin layer (63) in sequence. The copper layer (61) is located on the surface of the angled electrode (3), the nickel layer (62) covers the outside of the copper layer (61), and the tin layer (63) covers the outside of the nickel layer (62).

6. A method for manufacturing a low-loss inductor, used to manufacture the low-loss inductor according to any one of claims 1-5, characterized in that, Includes the following steps: S1: Powder mixing: Weigh nickel-iron alloy powder with a particle size of 3~6μm and nano-crystal seed material at a mass ratio of 4:6, put them into a mixing device and stir until uniform. Add the preset amount of epoxy adhesive to the mixed powder and continue stirring until the epoxy adhesive uniformly coats the surface of the powder. The coated material is first baked and granulated, then cooled and baked and granulated a second time to obtain a low-loss formula powder. S2: Magnetic core (1) prefabrication: The low-loss formula powder obtained in S1 is placed into the prefabrication molds corresponding to type T, type E, type I and type R respectively, and pressed into shape under specific pressure to obtain pre-formed magnetic core (1). S3: Winding: Using silver-plated enameled copper wire (2), the silver-plated enameled copper wire (2) is tightly wound onto the outer surface of the pre-formed magnetic core (1) obtained in S2 according to the number of turns required by the coil drawing; the two ends of the copper wire (2) are bent twice or more using a bending device to form bent electrodes (3) to obtain the inductor semi-finished product; the structure of the silver-plated enameled copper wire (2) is consistent with the copper wire (2) in claim 3; S4: Molding: The inductor semi-finished product obtained in S3 is inserted into the molding cavity, and the whole product is formed by selecting cold pressing or hot pressing process. S5: Baking: Place the semi-finished inductor product formed in S4 into a baking oven and bake it in the following order: 70℃ for 20 minutes, 90℃ for 20 minutes, 120℃ for 20 minutes, and 160℃ for 1 hour. S6: Grinding: Fix the baked inductor semi-finished product from S5 onto the grinding equipment and grind to remove the burrs on the surface of the inductor semi-finished product. S7: Chamfering: Place the inductor semi-finished product ground in S6 into the chamfering equipment to chamfer the sharp edges and corners of the inductor semi-finished product. S8: Spraying: The inductor semi-finished product after chamfering in S7 is surface-wetting and preheated. After preheating, it is placed in a roller and then the insulating ink is sprayed onto the outer surface of the inductor semi-finished product by thermal spraying, leaving only the folded electrode exposed (3). After spraying, the product is placed in an environment of 180-220℃ and kept warm for 120 minutes to allow the ink to solidify and form an ink layer (5). S9: Laser and electroplating: Laser equipment is used to laser process the surface of the corner electrode (3) of the inductor semi-finished product after spraying in S8 to remove the paint film (4) and insulating material on the surface of the corner electrode (3); The product is placed in an electroplating tank, and copper layer (61), nickel layer (62), tin layer (63) are electroplated in sequence, and an electrode electroplating layer (6) is formed on the surface to obtain a low-loss inductor.

7. A method for manufacturing a low-loss inductor according to claim 6, characterized in that: In step S4, the molding parameters of the inductor semi-finished product are: molding temperature range of 25-180℃, holding time range of 10-120S, and molding pressure range of 300-1000MPa.

8. A method for manufacturing a low-loss inductor according to claim 6, characterized in that: In step S6, the grinding parameters set for the grinding equipment are: grinding speed range of 300-1300 r / min and single cutting depth range of 0.02-0.08 mm.

9. A method for manufacturing a low-loss inductor according to claim 6, characterized in that: In step S7, the chamfering parameters of the chamfering equipment are: chamfering speed range of 15-25 r / min and chamfering time range of 1-10 min.

10. A method for manufacturing a low-loss inductor according to claim 6, characterized in that: In step S8, the preheating temperature range of the impregnated inductor semi-finished product is 100-150℃, and the heat preservation time ranges from 10 to 30 minutes; the rotation speed range of the roller is 8-12 r / min; the parameters of thermal spraying are: the spray gun distance range is 13-15 cm, the spray gun nozzle diameter range is 0.3-0.5 mm, and the spray gun air pressure range is 0.1-0.3 MPa.

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