Inorganic insulation integrally-formed power inductor and preparation method thereof

Abstract

The invention relates to the technical field of inductors, in particular to an inorganic insulation integrally-formed power inductor and a preparation method thereof. The method comprises the following steps: S1, selecting a coil; s2, pre-stretching the coil; s3, pre-coating of inorganic powder is carried out; s4, pressing the magnetic powder; s5, sintering the ceramic layer at high temperature; and S6, integrally forming the inductor. By reasonably selecting the material and shape of the coil and the type of the magnetic powder and combining high-temperature sintering at the temperature of 250 DEG C or above, the magnetic conductivity and the bias resistance are improved, the diversified requirements of high frequency, high temperature, high power density and the like are met, and the performance of insulation, heat conduction and the like can be optimized; according to the integrated forming process, coil pre-packaging and magnetic core forming are completed in one step, production procedures are reduced, process integration and production efficiency are improved, production cost is reduced, the utilization rate of a magnetic core window reaches 100%, and the product size is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of inductors, and in particular to an inorganic insulating integrated molded power inductor and a preparation method thereof. Background Art

[0002] Inorganic insulated integrated molded power inductors and their preparation methods are widely used in the inductor field, primarily for protection. Prior art inorganic insulated integrated molded power inductors and their preparation methods have the following problems. To address these technical issues, those skilled in the art have made the following efforts. For example, Chinese patent publication No. discloses a method for the same. However, the above solution still has the following unresolved issues: Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide an inorganic insulating integrated molded power inductor and a preparation method thereof.

[0004] The technical solution adopted in the present invention is as follows: A method for preparing an inorganic insulating integrated molded power inductor comprises the following steps: S1. Coil selection: select flat wire, round wire or stranded wire as the selected object; S2. Pre-stretching of coils: Pre-stretching the pitch of the selected object after winding so that the line spacing meets the winding specification requirements; S3. Pre-coating of inorganic powder: Pre-coating the outer layer of the stretched coil with inorganic powder to form an inorganic-wrapped wire. There are three methods for pre-coating inorganic powder: Sol-gel method: The coil is placed in a sol of inorganic powder, which is gelled and dried to form a pre-coating layer; Lost wax method: Coat the surface of the coil with a wax pattern, evenly absorb the inorganic powder and then dissolve and remove the wax to form a pre-coating layer; Adhesive method: Use high temperature resistant adhesive to evenly bond inorganic powder to form a pre-coating layer; S4. Pressing of magnetic powder: The inorganic coated wire is placed inside the mold, then filled with magnetic powder and pressed according to the parameters to form the wire. The following two actions are completed at the same time: The coil is compressed and the pre-stretched pitch is squeezed inwards by the die, the wire spacing is reduced and the space occupied becomes smaller; Pre-pressing of magnetic powder: Pre-pressing magnetic powder on the outer layer of the inorganic wrapped wire to improve magnetic permeability and anti-bias performance; S5. High-temperature sintering of the ceramic layer: The wrapped wire formed by pressing is sintered at a high temperature under the sintering temperature, and a uniform and dense ceramic layer is formed after cooling; S6. Integrated molding of inductors: After high-temperature sintering, the products are assembled into the core and base separately to obtain power inductors.

[0005] This technical solution achieves a more compact and high-performance inorganic insulated, integrated molded power inductor by pre-stretching the coils to control wire spacing, using a mold to compress the coils to reduce footprint, optimizing magnetic material properties through high-temperature sintering, and improving core window utilization through integrated molding. This reduces product volume while improving permeability and bias resistance, resulting in a more compact and high-performance inorganic insulated, integrated molded power inductor. Specifically, the preparation method accommodates different types of coils, such as flat, round, or stranded wire. The appropriate wire type can be flexibly selected based on the application scenario and performance requirements to meet the high-frequency, high-temperature, and high-power density operating requirements of power inductors. Pre-stretching the pitch after winding ensures a uniform wire spacing, allowing for uniform interaction with the inorganic and magnetic powders. Three different pre-coating processes are described. The first, a sol-gel method, involves hydrolysis and polycondensation of metal alkoxides or other precursors in the sol to form a gel with a three-dimensional network structure, which encapsulates the coil. During the drying process, the solvent evaporates and the gel gradually shrinks, ultimately forming a uniform, dense pre-coating layer of inorganic powder. The sol-gel method precisely controls the thickness and composition of the coating, and provides a strong bond between the coating and the coil. The second method, the lost wax method, utilizes the plasticity and solubility of wax to first form a wax mold on the coil surface, which serves as a template for the inorganic powder to be adsorbed. After the inorganic powder is evenly adsorbed on the wax mold, the wax mold is dissolved, leaving the powder layer on the coil surface to form a pre-coating layer. The lost wax method produces coatings with complex shapes and high precision, while ensuring coating uniformity. The third method, the adhesive method, utilizes the viscosity of a high-temperature resistant adhesive to firmly bond the inorganic powder to the coil surface. The high-temperature resistant adhesive can maintain stable performance in high-temperature environments, ensuring that the pre-coating layer will not fall off or deteriorate during subsequent high-temperature sintering processes. The adhesive method is simple to operate, low-cost, and suitable for large-scale production. Then, through the pressure of the mold, the coil geometry is modified, making it more compact. This compression of the coil increases the energy density of the inductor and reduces the product's volume. The pressure also forces the magnetic powder particles closer together, forming a specific magnetic circuit structure. The magnetic powder's high magnetic permeability enhances the inductor's magnetic field sensing capability and increases its inductance. Furthermore, this optimal magnetic circuit structure improves the inductor's bias resistance, ensuring it maintains good performance stability even under biased magnetic fields. Traditional one-piece molded inductors operate at relatively low sintering temperatures, preventing the magnetic powder particles from fully bonding together to form a complete magnetic circuit structure. This technical solution achieves a sintering temperature above 250°C. This high temperature intensifies atomic diffusion between the magnetic powder particles, promoting bonding and forming a denser ceramic layer. Traditional inductor production processes typically require separate steps, including coil fabrication, insulation treatment, and core assembly, resulting in long production cycles and high costs. This design, however, utilizes an integrated molding process, combining coil pre-packaging and core molding in a single step. This significantly simplifies the production process, improves efficiency, and reduces costs.

[0006] In addition, the inorganic insulating integrated molded power inductor and its preparation method proposed in the present invention also have the following additional technical features: According to an embodiment of the present invention, in the coil selection in step S1, the material of the coil is copper, aluminum or copper-clad aluminum; the cross-sectional shape of the coil is rectangular, circular or hollow special-shaped.

[0007] In this technical solution, the material and cross-sectional shape of the coil are used in different inductor products. By rationally selecting the material and shape, the advantages of various materials can be fully utilized, the performance of the inductor can be optimized, and the diverse needs of inductors in different fields can be met.

[0008] According to one embodiment of the present invention, in the pre-stretching of the coil in step S2, one end of the coil is fixed and the other end is clamped on a tooling, and the tooling drives the two ends of the coil to stretch relative to each other.

[0009] In this technical solution, during the stretching process, the tooling controls the coil according to preset parameters, such as stretching force, stretching speed, and stretching distance.

[0010] According to one embodiment of the present invention, in the pre-coating of inorganic powder in step S3, the inorganic powder is a composite powder composed of one or more of aluminum oxide, aluminum nitride, boron nitride, and silicon nitride.

[0011] In this technical solution, in high-frequency inductors, rapid changes in current can easily cause electromagnetic interference and leakage between coils. The high resistivity of the aluminum oxide insulation layer can significantly reduce interference. In high-power inductors, the problem of heat accumulation is particularly prominent. The high thermal conductivity of aluminum nitride effectively solves this problem, improves the heat dissipation efficiency of the inductor, and ensures that it can still work normally in a high-temperature environment. The significant advantage of boron nitride is that it has insulation properties in a wide temperature range and can maintain stable insulation properties in a wide temperature range from low to high temperatures. The insulation layer formed by silicon nitride powder can withstand mechanical friction and vibration, and is not prone to breakage and peeling, thereby ensuring the durability of the insulation performance. The composite powder can achieve complementary and synergistic performance enhancement, in which aluminum oxide provides a stable high-resistivity insulation foundation, aluminum nitride improves heat dissipation performance while ensuring insulation, boron nitride gives the coating layer insulation capabilities in a wide temperature range, and silicon nitride enhances the mechanical strength of the insulation layer.

[0012] According to one embodiment of the present invention, in the step S4 of compacting the magnetic powder, the magnetic powder is crystalline soft magnetic powder or amorphous soft magnetic powder, and the crystalline soft magnetic powder includes iron silicon powder and sendust powder.

[0013] In this technical solution, iron-silicon alloys have high saturation magnetic induction. Under the same magnetic field strength, magnetic cores made from iron-silicon powder can store more magnetic energy, enabling inductors to achieve higher inductance in a smaller volume, facilitating miniaturization and integration. Iron-silicon powder also has low core loss. The addition of aluminum to sendust powder also improves the magnetic and mechanical properties of the core.

[0014] According to one embodiment of the present invention, in the step S4 of compacting the magnetic powder, a cavity for placing the coil is reserved in the mold, and the shape of the cavity ensures that the coil pitch can be squeezed inward and that the magnetic powder can be evenly filled to the outside of the pre-coating layer.

[0015] In this technical solution, the coil has a certain pitch and elasticity in its natural state. When it is placed in the mold cavity and the magnetic powder is compacted, as the compaction pressure is applied, the magnetic powder will be squeezed outward; the special shape of the cavity can guide the extrusion force to act on the coil, causing the coil pitch to gradually shrink inward.

[0016] According to one embodiment of the present invention, in the high-temperature sintering of the ceramic layer in step S5, the high-temperature sintering is performed at a sintering temperature of 250° C. or higher.

[0017] In this technical solution, traditional one-piece molded inductors use epoxy resin or plastic-coated wire wrap, which has limited insulation strength. This limitation results in smaller molded sizes, restricting power usage and product performance. Traditional one-piece molded inductors also have a relatively low curing temperature of 150-250°C due to the resin's temperature resistance. This technical solution can achieve a sintering temperature above 250°C, improving the magnetic material's permeability and bias resistance.

[0018] According to one embodiment of the present invention, in the high-temperature sintering of the ceramic layer in step S5 , the thickness of the uniform and dense ceramic layer is in the range of 10-200 μm.

[0019] This technical solution uses a coating process to form a uniform, dense, and thin ceramic layer of 10-200 μm before the wire package, and the ceramic layer can achieve the composite functions of insulation and heat conduction.

[0020] According to one embodiment of the present invention, in the integrated molding of the inductor in step S6, an opening is reserved in the magnetic core for assembling the coil, and the opening utilization rate is 100%.

[0021] In this technical solution, the product is integrally formed, and the core window utilization rate can reach 100%, which greatly improves the core utilization rate and reduces the product volume.

[0022] To achieve the above-mentioned object, the present invention also provides an inorganic insulating integrated molded power inductor.

[0023] An inorganic insulating integrated molded power inductor, comprising: The coil is made of flat wire, round wire or stranded wire in a vertical winding method. The outside of the coil is wrapped with a ceramic layer. The ceramic layer is made of inorganic powder and magnetic powder sintered at a high temperature above 250°C. It has the characteristics of insulation and thermal conductivity, high magnetic permeability and anti-bias. The magnetic core is provided with an opening for winding the coil, and the coil is wound inside the opening; the center column or upper and lower yokes of the magnetic core are prefabricated with magnetic blocks of different materials to optimize the magnetic circuit. The material and shape of the center column or upper and lower yokes can be adjusted and replaced according to needs; The base has a magnetic core fixed on it and has pins reserved for fixing the coil lead wires.

[0024] In this technical solution, the wire package pre-packaging and magnetic core molding are completed in one step, which reduces the production process and has high process integration. The core center column or the upper and lower yokes can be prefabricated with magnetic blocks of different materials. The material and shape of the core center column or the upper and lower yokes can be adjusted and replaced according to needs to optimize the magnetic circuit.

[0025] Compared with the prior art, the present invention has the following beneficial effects: (1) Performance optimization and diversified adaptation: By rationally selecting coil material and shape, magnetic powder type, and combining high-temperature sintering above 250°C, the magnetic permeability and anti-bias capability are improved to meet diverse requirements such as high frequency, high temperature, and high power density, and to optimize insulation and thermal conductivity.

[0026] (2) Process simplification and efficiency improvement: The one-piece molding process completes the wire package pre-packaging and core molding in one step, reducing production processes, improving process integration and production efficiency, reducing production costs, and achieving 100% utilization of the core window, reducing product volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the process of the preparation method of the present invention.

[0028] Figure 2 It is a state diagram of step S2 of the preparation method of the present invention.

[0029] Figure 3 It is a state diagram of step S3 of the preparation method of the present invention.

[0030] Figure 4 It is a state diagram of step S4 of the preparation method of the present invention.

[0031] Figure 5 It is a state diagram of step S5 of the preparation method of the present invention.

[0032] Figure 6 It is a schematic structural diagram of the power inductor of the present invention.

[0033] Figure 7 yes Figure 6 DD cross-section view of a medium-power inductor.

[0034] In the figure: 1. Coil; 11. Inorganic powder; 12. Magnetic powder; 13. Ceramic layer; 2. Magnetic core; 3. Base. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0036] Example 1 like Figure 1 As shown, this embodiment provides a method for preparing an inorganic insulating integrated molded power inductor, comprising the following steps: S1. Coil selection: select flat wire, round wire or stranded wire as the selected object; S2. Pre-stretching of coil: Figure 2 As shown, the selected object is wound and pre-stretched to make the line spacing meet the winding specification requirements; S3. Pre-coating of inorganic powder: Figure 3 As shown, inorganic powder 11 is pre-coated on the outer layer of the stretched coil 1 to form an inorganic wrapped wire; the pre-coating method of the inorganic powder includes the following three methods: Sol-gel method: The coil 1 is placed in a sol of inorganic powder, gelled, and dried to form a pre-coating layer; Lost wax method: a wax pattern is applied to the surface of the coil 1, and the inorganic powder 11 is evenly adsorbed and then dissolved to remove the wax, forming a pre-coating layer; Adhesive method: using a high temperature resistant adhesive to evenly bond the inorganic powder 11 to form a pre-coating layer; S4. Compaction of magnetic powder: Figure 4 As shown, the inorganic coated wire is placed inside the mold, and then filled with magnetic powder 12, and pressure is applied according to parameters to perform compaction molding, while completing the following two actions: The coil is compressed and the pre-stretched pitch is squeezed inwards by the die, the wire spacing is reduced and the space occupied becomes smaller; Pre-pressing of magnetic powder: Pre-pressing magnetic powder 12 on the outer layer of the inorganic wrapped wire to improve magnetic permeability and anti-bias performance; S5. High temperature sintering of ceramic layer: Figure 5 As shown, the wrapped wire formed by pressing is sintered at a high temperature at a sintering temperature, and a uniform and dense ceramic layer 13 is formed after cooling; S6. Integrated molding of the inductor: After high-temperature sintering, the product is assembled into the magnetic core 2 and the base 3 to obtain a power inductor.

[0037] This technical solution controls the wire spacing by pre-stretching the coil 1, compresses the coil 1 by die pressing to reduce the space occupied, optimizes the performance of the magnetic material by high-temperature sintering, and improves the window utilization rate of the magnetic core 2 by integrated molding, thereby reducing the volume of the product while improving the magnetic permeability and anti-bias capability, thereby preparing an inorganic insulating integrated molded power inductor in a more compact and high-performance manner. Specifically, the preparation method meets the needs of different types of coils 1, such as flat wire, round wire or stranded wire, and flexibly selects the appropriate wire type according to different application scenarios and performance requirements to meet the working requirements of power inductors under high frequency, high temperature, high power density and other conditions. The pitch is pre-stretched after winding, and the appropriate wire spacing can interact evenly with the inorganic powder 11 and the magnetic powder 12. Three different processes are given for the pre-coating method. The first, the sol-gel method, is to form a gel with a three-dimensional network structure by hydrolyzing and polycondensing the metal alkoxide or other precursors in the sol, and wrap the coil 1 therein. During the drying process, the solvent evaporates and the gel gradually shrinks, eventually forming a uniform and dense pre-coating layer of inorganic powder 11; the sol-gel method precisely controls the thickness and composition of the coating, and the bonding force between the coating and the coil 1 is relatively strong. The second method, the lost wax method, utilizes the plasticity and solubility of wax to first form a layer of wax mold on the surface of the coil 1 as an adsorption template for the inorganic powder; after the inorganic powder 11 is uniformly adsorbed on the surface of the wax mold, the wax mold is dissolved so that the powder layer remains on the surface of the coil 1 to form a pre-coating layer; the lost wax method can prepare coatings with complex shapes and high precision, and can ensure the uniformity of the coating. The third method, the adhesive method, utilizes the viscosity of a high-temperature resistant adhesive to firmly bond the inorganic powder 11 to the surface of the coil 1. The high-temperature resistant adhesive can still maintain stable performance in a high-temperature environment, ensuring that the pre-coating layer will not fall off or deteriorate in subsequent processes such as high-temperature sintering. The adhesive method is simple to operate, low in cost, and suitable for large-scale production. Then, through the pressure of the mold, the coil geometry is altered, making it more compact. This compression of the coil increases the energy density of the inductor and reduces the product's volume. The pressure also forces the magnetic powder 12 particles to move closer together, forming a specific magnetic circuit structure. The magnetic powder 12 has a high magnetic permeability, which enhances the inductor's magnetic field sensing capability and increases its inductance. Furthermore, this rational magnetic circuit structure improves the inductor's bias resistance, allowing it to maintain good performance stability even under biased magnetic fields. Because traditional one-piece molded inductors have low sintering temperatures, the magnetic powder 12 particles cannot fully bond together to form a complete magnetic circuit structure. However, this technical solution achieves a sintering temperature above 250°C. This high temperature intensifies atomic diffusion between the magnetic powder 12 particles, promoting bonding between the particles and forming a denser ceramic layer 13. Traditional inductor production processes typically require multiple separate steps, including coil production, insulation treatment, and assembly of the magnetic core 2, resulting in long production cycles and high costs. This design, however, utilizes an integrated molding process, completing coil pre-packaging and core 2 molding in a single step, significantly simplifying the production process, improving production efficiency, and reducing production costs.

[0038] In addition, the method for preparing the inorganic insulating integrated molded power inductor according to the present invention also has the following additional technical features: According to an embodiment of the present invention, in the coil selection in step S1, the material of the coil is copper, aluminum or copper-clad aluminum; the cross-sectional shape of the coil is rectangular, circular or hollow special-shaped.

[0039] In this technical solution, the material and cross-sectional shape of the coil are used in different inductor products. By rationally selecting the material and shape, the advantages of various materials can be fully utilized, the performance of the inductor can be optimized, and the diverse needs of inductors in different fields can be met.

[0040] According to one embodiment of the present invention, in the pre-stretching of the coil in step S2, one end of the coil is fixed and the other end is clamped on a tool, and the tool drives the two ends of the coil 1 to stretch relative to each other.

[0041] In this technical solution, during the stretching process, the tooling controls the coil 1 according to preset parameters, such as the stretching force, stretching speed, and stretching distance.

[0042] According to one embodiment of the present invention, in the inorganic powder pre-coating step S3, the inorganic powder 11 is a composite powder composed of one or more of aluminum oxide, aluminum nitride, boron nitride, and silicon nitride.

[0043] In this technical solution, in high-frequency inductors, rapid changes in current can easily cause electromagnetic interference and leakage between coils 1. The high resistivity of the aluminum oxide insulation layer can significantly reduce interference. In high-power inductors, the problem of heat accumulation is particularly prominent. The high thermal conductivity of aluminum nitride effectively solves this problem, improves the heat dissipation efficiency of the inductor, and ensures that it can still work normally in a high-temperature environment. The significant advantage of boron nitride is that it has insulation properties in a wide temperature range and can maintain stable insulation properties in a wide temperature range from low to high temperatures. The insulating layer formed by silicon nitride powder can withstand mechanical friction and vibration, and is not prone to breakage and peeling, thereby ensuring the durability of the insulation performance. The composite powder can achieve performance complementarity and synergistic enhancement, wherein aluminum oxide provides a stable high-resistivity insulation foundation, aluminum nitride improves heat dissipation performance while ensuring insulation, boron nitride gives the coating layer insulation capabilities in a wide temperature range, and silicon nitride enhances the mechanical strength of the insulating layer.

[0044] According to one embodiment of the present invention, in the step S4 of compacting the magnetic powder, the magnetic powder 12 is crystalline soft magnetic powder or amorphous soft magnetic powder, and the crystalline soft magnetic powder includes iron silicon powder and sendust powder.

[0045] In this technical solution, iron-silicon alloys have a high saturation magnetic induction intensity. Under the same magnetic field strength, the magnetic core 2 made of iron-silicon powder can store more magnetic energy, thereby achieving higher inductance in a smaller inductor volume, which is conducive to miniaturization and integration of inductors. Iron-silicon powder also has low losses in the magnetic core 2. Sendust powder also improves the magnetic and mechanical properties of the magnetic core 2 by adding aluminum.

[0046] According to one embodiment of the present invention, in the step S4 of compacting the magnetic powder, a cavity for placing the coil is reserved in the mold, and the shape of the cavity ensures that the pitch of the coil 1 can be squeezed inward and that the magnetic powder 12 can be evenly filled to the outside of the pre-coating layer.

[0047] In this technical solution, the coil 1 has a certain pitch and elasticity in its natural state. When it is placed in the mold cavity and the magnetic powder 12 is compacted, as the compaction pressure is applied, the magnetic powder 12 will be squeezed outward; the special shape of the cavity can guide the extrusion force to act on the coil 1, causing the pitch of the coil 1 to gradually shrink inward.

[0048] According to one embodiment of the present invention, in the high-temperature sintering of the ceramic layer in step S5, the high-temperature sintering is performed at a sintering temperature of 250° C. or higher.

[0049] In this technical solution, traditional one-piece molded inductors use epoxy resin or plastic-coated wire wrap, which has limited insulation strength. This limitation results in smaller molded sizes, restricting power usage and product performance. Traditional one-piece molded inductors also have a relatively low curing temperature of 150-250°C due to the resin's temperature resistance. This technical solution can achieve a sintering temperature above 250°C, improving the magnetic material's permeability and bias resistance.

[0050] According to one embodiment of the present invention, in the high-temperature sintering of the ceramic layer in step S5 , the thickness of the uniform and dense ceramic layer is in the range of 10-200 μm.

[0051] The present technical solution can form a uniform and dense ceramic layer 13 with a small thickness of 10-200 μm before the wire package through the coating process, and the ceramic layer 13 can achieve the composite functions of insulation and heat conduction.

[0052] According to one embodiment of the present invention, in the integrated molding of the inductor in step S6 , an opening is reserved in the magnetic core 2 for assembling the coil, and the opening utilization rate is 100%.

[0053] In this technical solution, the product is integrally formed, and the utilization rate of the core 2 window can reach 100%, which greatly improves the utilization rate of the core 2 and reduces the volume of the product.

[0054] Example 2 Based on Example 1, Figure 6 and Figure 7 As shown, this embodiment provides an inorganic insulating integrated molded power inductor, including: Coil 1, which is formed by vertically winding flat wire, round wire, or stranded wire, is wrapped with a ceramic layer 13. The ceramic layer 13 is formed by sintering inorganic powder 11 and magnetic powder 12 at a high temperature above 250°C, and has the characteristics of insulation and thermal conductivity, high magnetic permeability, and anti-bias. The magnetic core 2 is provided with an opening for winding the coil 1, and the coil 1 is wound inside the opening; the center column or upper and lower yokes of the magnetic core 2 are prefabricated with magnetic blocks of different materials to optimize the magnetic circuit, and the material and shape of the center column or upper and lower yokes can be adjusted and replaced according to needs; The base 3 has the magnetic core 2 fixed thereon and has pins reserved for fixing the lead wires of the coil 1.

[0055] In this technical solution, the pre-packaging of the wire package and the molding of the magnetic core 2 are completed in one step, which reduces the production process and has high process integration; the center column or the upper and lower yokes of the magnetic core 2 can be prefabricated with magnetic blocks of different materials, and the material and shape of the center column or the upper and lower yokes of the magnetic core 2 can be adjusted and replaced according to needs to optimize the magnetic circuit.

[0056] Although the present invention is described in detail with reference to the accompanying drawings and in combination with preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications or substitutions shall be within the scope of the present invention. Any person skilled in the art who can easily conceive of changes or substitutions within the technical scope disclosed in the present invention shall be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope of protection of the claims.

Claims

1. A method for preparing an inorganic insulating integrated molded power inductor, characterized in that: The steps include: S1. Coil selection: select flat wire, round wire or stranded wire as the selected object; S2. Pre-stretching of coils: Pre-stretching the pitch of the selected object after winding so that the line spacing meets the winding specification requirements; S3. Pre-coating of inorganic powder: Pre-coating the outer layer of the stretched coil (1) with inorganic powder (11) to form an inorganic wrapped wire; the pre-coating method of the inorganic powder (11) includes the following three methods: Sol-gel method: placing the coil (1) in a sol of inorganic powder (11), gelling it, and drying it to form a pre-coating layer; Lost wax method: a wax pattern is applied to the surface of the coil (1), and inorganic powder (11) is uniformly adsorbed and then dissolved to remove the wax, thereby forming a pre-coating layer; Adhesive method: using a high temperature resistant adhesive to evenly bond the inorganic powder (11) to form a pre-coating layer; S4. Compression of magnetic powder: Place the inorganic coated wire inside the mold, then fill it with magnetic powder (12), and apply pressure according to the parameters to perform compression molding, while completing the following two actions: The coil is compressed and the pre-stretched pitch is squeezed inwards by the die, the wire spacing is reduced and the space occupied becomes smaller; Pre-pressing magnetic powder, wherein the outer layer of the inorganic wrapped wire is pre-pressed with magnetic powder (12) for improving magnetic permeability and anti-bias performance; S5, high temperature sintering of the ceramic layer: the wrapped wire formed by pressing is sintered at a high temperature at a sintering temperature, and a uniform and dense ceramic layer (13) is formed after cooling; S6. Integrated molding of the inductor: After the product is sintered at high temperature, the magnetic core (2) and the base (3) are assembled separately to obtain a power inductor.

2. The method for preparing an inorganic insulating integrated molded power inductor according to claim 1, wherein: In the step S1 of selecting the coil, the material of the coil is copper, aluminum or copper-clad aluminum; the cross-sectional shape of the coil is rectangular, circular or hollow special-shaped.

3. The method for preparing an inorganic insulating integrated molded power inductor according to claim 1, wherein: In the pre-stretching of the coil in step S2, one end of the coil is fixed and the other end is clamped on a tool, and the tool drives the two ends of the coil (1) to stretch relative to each other.

4. The method for preparing an inorganic insulating integrated molded power inductor according to claim 1, wherein: In the step S3 of pre-coating the inorganic powder, the inorganic powder (11) is a composite powder composed of one or more of aluminum oxide, aluminum nitride, boron nitride, and silicon nitride.

5. The method for preparing an inorganic insulating integrated molded power inductor according to claim 1, wherein: In the step S4 of compacting the magnetic powder, the magnetic powder (12) is crystalline soft magnetic powder or amorphous soft magnetic powder, and the crystalline soft magnetic powder includes iron silicon powder and sendust powder.

6. The method for preparing the inorganic insulating integrated molded power inductor according to claim 1 or 5, characterized in that: In the step S4 of compacting the magnetic powder, a cavity for placing the coil is reserved in the mold, and the shape of the cavity ensures that the pitch of the coil (1) can be squeezed inward and that the magnetic powder (12) can be evenly filled to the outside of the pre-coating layer.

7. The method for preparing an inorganic insulating integrated molded power inductor according to claim 1, wherein: In the high-temperature sintering of the ceramic layer in step S5 , the high-temperature sintering is performed at a sintering temperature of 250° C. or higher.

8. The method for preparing an inorganic insulating integrated molded power inductor according to claim 1 or 7, wherein: During the high-temperature sintering of the ceramic layer in step S5 , the thickness of the uniform and dense ceramic layer is in the range of 10-200 μm.

9. The method for preparing an inorganic insulating integrated molded power inductor according to claim 1, wherein: In the integrated forming of the inductor in step S6, the magnetic core (2) reserves an opening for assembling the coil, and the opening utilization rate is 100%.

10. An inorganic insulated integrated molded power inductor, comprising the method for preparing the inorganic insulated integrated molded power inductor according to any one of claims 1 to 9, wherein: include: The coil (1) is formed by vertically winding a flat wire, a round wire or a stranded wire, and the outside of the coil is wrapped with a ceramic layer (13); the ceramic layer (13) is formed by sintering an inorganic powder (11) and a magnetic powder (12) at a high temperature of more than 250° C. and has the characteristics of insulation and thermal conductivity, high magnetic permeability and anti-bias. The magnetic core (2) is provided with an opening for winding the coil (1), and the coil (1) is wound in the opening; the center column or upper and lower yokes of the magnetic core (2) are optimized by prefabricating magnetic blocks of different materials, and the material and shape of the center column or upper and lower yokes are adjusted and replaced according to needs; The base (3) is fixed with the magnetic core (2) and has a pin reserved for fixing the lead wire of the coil (1).

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