A production process of a common mode inductor

Abstract

The application discloses a production process of a common-mode inductor and belongs to the technical field of inductor manufacturing. The production process comprises the following steps: step S1, manufacturing a coil; step S2, preparing an inductor preliminary product; step S3, placing the inductor preliminary product pins in a tray tool in an orderly manner and inversely clamping a paint dipping tray, turning over the tray tool and the paint dipping tray as a whole, moving away the tray tool, placing the inductor preliminary product pins in the paint dipping tray in an upward manner, and then transferring the paint dipping tray to a paint dipping groove to soak in insulating liquid; and step S4, obtaining a common-mode inductor product after drying and adjusting the pin spacing. The application only needs to simply control the liquid level of the insulating liquid in the paint dipping groove, so that the liquid level of the insulating liquid can immerse the coil of the inductor preliminary product without contacting the pins, the pins are ensured not to be contaminated by the insulating liquid, the generation of paint nodules on the pins is avoided, the production process and production cost can be controlled, and the product quality is improved.

Description

Technical Field

[0001] This invention belongs to the field of inductor manufacturing technology, specifically relating to a production process for a common-mode inductor. Background Technology

[0002] Common-mode inductors are mainly used to filter out common-mode interference signals. The two windings have the same number of turns and wire diameter, and the same terminals are the same. When a common-mode signal flows through a common-mode inductor, the magnetic flux coupling generated by the two signals is strengthened, presenting a high impedance to the common-mode signal and having a good filtering effect. When a normal differential-mode signal flows through a common-mode inductor, the magnetic flux generated by the two signals just cancels each other out, presenting a low impedance characteristic to the differential-mode signal.

[0003] Current technology involves randomly introducing the coils of the pre-made inductor into an impregnation bath, completely covering them with insulating varnish. After impregnation, the coils are placed on a tray for baking. This process results in the coil leads also being impregnated with insulating varnish. Although most of the insulating varnish on the leads melts during soldering, small amounts of varnish residue can still cause incomplete soldering or missed solder joints, requiring manual resoldering, increasing production costs, and reducing product quality and reputation. Furthermore, adding a lead preheating step after impregnation to remove varnish residue further increases production steps and costs. Therefore, developing a common-mode inductor manufacturing process that prevents the leads from being impregnated with insulating varnish is an urgent problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a manufacturing process for common mode inductors to solve the problems in the prior art.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A manufacturing process for a common-mode inductor includes the following steps:

[0007] Step S1: Making the coil: The bobbin is fed onto the winding machine chuck via a vibratory feeder, and then the enameled wire is automatically wound onto the bobbin to obtain the coil; the coil is conveyed onto the belt via a vibratory feeder, and then the clamp is used to apply flux and then solder the lead wire of the coil onto the pin pin to obtain the coil with leads;

[0008] Step S2: Preparation of the initial inductor: First, wrap the winding part of the coil with leads with Malait tape to obtain an insulated coil; then assemble the magnetic core onto the insulated coil, rotate the magnetic core, wrap Malait tape around the magnetic core, and after testing the inductance to ensure it is qualified, the initial inductor is obtained.

[0009] Step S3, Impregnation: First, neatly place the qualified inductor blanks with the leads facing down in the tray fixture. Then, invert the impregnation tray onto the tray fixture filled with the inductor blanks. After flipping the tray fixture and the impregnation tray over, remove the tray fixture above the impregnation tray. At this point, all the leads of the inductor blanks are placed upwards in the impregnation tray. Then, transfer the impregnation tray to the impregnation tank, controlling the level of the insulating liquid to submerge the coil without contacting the leads. Immerse at normal pressure for 10-15 minutes.

[0010] Step S4, Post-processing: After impregnation with varnish, air dry for 20 minutes, then bake in an oven to dry the insulating liquid; finally, use a lead-aligning fixture to adjust the lead spacing that has been deformed by heat to within the acceptable range, thus obtaining the finished common mode inductor.

[0011] Furthermore, the skeleton is a horizontal double-slot skeleton, and the number of winding coils and wire diameter of each slot are the same.

[0012] Furthermore, the insulating liquid is obtained by mixing insulating varnish and diluent at a mass ratio of 1:1, and the specific gravity of the insulating liquid is 0.905-0.925.

[0013] Furthermore, the oven temperature is set to 100-140℃, and the baking time is 2.5 hours.

[0014] Furthermore, the magnetic core is manufactured through the following steps:

[0015] Fe2O3, MnO, and ZnO were mixed in a molar ratio of 11:7:2 and pre-calcined in air to obtain a pre-calcined raw material. SiO2, CaO, Nb2O5, and CoO were then added to the pre-calcined raw material and pulverized using a sand mill. Phosphated iron-based nanocrystalline powder was then added and mixed. Silicone resin was then added and mixed and granulated. The mixture was then placed into a mold and pressed into shape. After molding, the mixture was sintered in a nitrogen atmosphere at 1000℃ for 3 hours. Finally, the interface was mirror-polished to obtain the magnetic core.

[0016] Furthermore, the pre-firing temperature is 900°C and the pre-firing time is 2 hours.

[0017] Furthermore, the amounts of SiO2, CaO, Nb2O5, and CoO used are 0.008%, 0.07%, 0.05%, and 0.02% of the total weight of the pre-calcined raw materials, respectively.

[0018] Furthermore, the phosphated iron-based nanocrystalline powder contains 0.03-0.05 wt% phosphoric acid, with the remainder being iron-based nanocrystalline powder, the sum of the two by mass percentage being 100%; the grade of the iron-based nanocrystalline powder is 1K107.

[0019] Furthermore, the amount of the phosphated iron-based nanocrystalline powder used is 3-5% of the total weight of the pre-calcined raw materials.

[0020] Furthermore, the amount of silicone resin used is 3-5% of the total weight of the pre-calcined raw materials.

[0021] Beneficial effects:

[0022] This invention, based on the traditional manganese-zinc ferrite core material, incorporates 3-5% phosphated iron-based nanocrystalline powder (0.03-0.05 wt% phosphoric acid content), which improves the core's saturation magnetic flux density, initial permeability, and Curie temperature, resulting in better magnetic properties. Compared to common-mode inductors made from traditional pure manganese-zinc ferrite cores, the common-mode inductor produced by this invention exhibits a significantly improved inductance coefficient (from 3500 to 4500). In practical applications, for the same inductance, the number of enameled wire windings in the common-mode inductor can be reduced, effectively lowering copper consumption and temperature rise; while for the same number of windings, a higher inductance can be obtained.

[0023] The manufacturing process of this invention first arranges the inductor blanks with their leads facing downwards neatly in a tray fixture. The tray fixture makes the placement of the inductor blanks faster and more efficient, and the fixture will not touch the leads, reducing the possibility of lead deformation. Then, by inverting the varnish-impregnating tray and flipping the tray fixture and varnish-impregnating tray as a whole, after removing the tray fixture, all the leads of the inductor blanks are neatly arranged upwards in the varnish-impregnating tray. During varnish impregnation, the varnish-impregnating tray is placed on the pads in the varnish-impregnating tank. By simply controlling the liquid level of the insulating liquid in the varnish-impregnating tank, the liquid level of the insulating liquid can be used to submerge the coil of the inductor blank without contacting the leads, ensuring that the leads do not get contaminated with insulating liquid, avoiding the formation of varnish nodules on the leads, making the production process and production costs controllable, and improving product quality. Attached Figure Description

[0024] The invention will now be further described with reference to the accompanying drawings.

[0025] Figure 1 This is a schematic diagram of the tray-setting fixture of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of the inductor prototype of the present invention placed in the tray fixture;

[0027] Figure 3 This is a schematic diagram of the structure of the paint-impregnating tray of the present invention being inverted on the tray-laying fixture;

[0028] Figure 4 This is a schematic diagram of the structure of the paint dipping tray of the present invention in the paint dipping tank;

[0029] Figure 5 yes Figure 4 A magnified view of a portion of point A in the middle.

[0030] In the diagram: 1. Plate-mounting fixture; 101. T-shaped slot; 2. Inductor prototype; 3. Enamel-impregnated tray; 301. Through hole; 4. Enamel-impregnated tank; 401. Insulating liquid; 402. Pad block. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1

[0033] This embodiment provides a magnetic core, which is manufactured through the following steps:

[0034] Fe2O3, MnO, and ZnO were mixed in a molar ratio of 11:7:2 and pre-calcined in air at 900°C for 2 hours to obtain a pre-calcined raw material. Then, 0.008% SiO2, 0.07% CaO, 0.05% Nb2O5, and 0.02% CoO by weight of the pre-calcined raw material were added and pulverized using a sand mill. After pulverization, 3% of phosphated iron-based nanocrystalline powder by weight of the pre-calcined raw material was added and mixed. The phosphated iron-based nanocrystalline powder contained 0.03 wt% phosphoric acid, and the remaining iron-based nanocrystalline powder was grade 1K107. Then, 3% of silicone resin by weight of the pre-calcined raw material was added for mixing and granulation. The mixture was then molded and sintered at 1000°C in a nitrogen atmosphere for 3 hours. The interface was then mirror-polished to obtain the magnetic core.

[0035] Example 2

[0036] This embodiment provides a magnetic core, which is manufactured through the following steps:

[0037] Fe2O3, MnO, and ZnO were mixed in a molar ratio of 11:7:2 and pre-calcined in air at 900°C for 2 hours to obtain a pre-calcined raw material. Then, 0.008% SiO2, 0.07% CaO, 0.05% Nb2O5, and 0.02% CoO by weight of the pre-calcined raw material were added and pulverized using a sand mill. After pulverization, 3.5% of phosphated iron-based nanocrystalline powder by weight of the pre-calcined raw material was added and mixed. The phosphated iron-based nanocrystalline powder contained 0.04 wt% phosphoric acid, and the remaining iron-based nanocrystalline powder was grade 1K107. Then, 3.5% of silicone resin by weight of the pre-calcined raw material was added for mixing and granulation. The mixture was then molded and sintered at 1000°C in a nitrogen atmosphere for 3 hours. The interface was then mirror-polished to obtain the magnetic core.

[0038] Example 3

[0039] This embodiment provides a magnetic core, which is manufactured through the following steps:

[0040] Fe2O3, MnO, and ZnO were mixed in a molar ratio of 11:7:2 and pre-calcined in air at 900°C for 2 hours to obtain a pre-calcined raw material. Then, 0.008% SiO2, 0.07% CaO, 0.05% Nb2O5, and 0.02% CoO by weight of the pre-calcined raw material were added and pulverized using a sand mill. After pulverization, 4% of phosphated iron-based nanocrystalline powder by weight of the pre-calcined raw material was added and mixed. The phosphated iron-based nanocrystalline powder contained 0.04 wt% phosphoric acid, and the remaining iron-based nanocrystalline powder was grade 1K107. Then, 4% of silicone resin by weight of the pre-calcined raw material was added for mixing and granulation. The mixture was then molded and sintered at 1000°C in a nitrogen atmosphere for 3 hours. The interface was then mirror-polished to obtain the magnetic core.

[0041] Example 4

[0042] This embodiment provides a magnetic core, which is manufactured through the following steps:

[0043] Fe2O3, MnO, and ZnO were mixed in a molar ratio of 11:7:2 and pre-calcined in air at 900°C for 2 hours to obtain a pre-calcined raw material. Then, 0.008% SiO2, 0.07% CaO, 0.05% Nb2O5, and 0.02% CoO by weight of the pre-calcined raw material were added and pulverized using a sand mill. After pulverization, 4.5% of phosphated iron-based nanocrystalline powder by weight of the pre-calcined raw material was added and mixed. The phosphated iron-based nanocrystalline powder contained 0.04 wt% phosphoric acid, and the remaining iron-based nanocrystalline powder was grade 1K107. Then, 4.5% of silicone resin by weight of the pre-calcined raw material was added for mixing and granulation. The mixture was then molded and sintered at 1000°C in a nitrogen atmosphere for 3 hours. The interface was then mirror-polished to obtain the magnetic core.

[0044] Example 5

[0045] This embodiment provides a magnetic core, which is manufactured through the following steps:

[0046] Fe2O3, MnO, and ZnO were mixed in a molar ratio of 11:7:2 and pre-calcined in air at 900°C for 2 hours to obtain a pre-calcined raw material. Then, 0.008% SiO2, 0.07% CaO, 0.05% Nb2O5, and 0.02% CoO by weight of the pre-calcined raw material were added and pulverized using a sand mill. After pulverization, 5% of phosphated iron-based nanocrystalline powder by weight of the pre-calcined raw material was added and mixed. The phosphated iron-based nanocrystalline powder contained 0.05 wt% phosphoric acid, and the remaining iron-based nanocrystalline powder was grade 1K107. Then, 5% of silicone resin by weight of the pre-calcined raw material was added for mixing and granulation. The mixture was then molded and sintered at 1000°C in a nitrogen atmosphere for 3 hours. The interface was then mirror-polished to obtain the magnetic core.

[0047] Comparative Example 1

[0048] Compared with Example 5, this comparative example does not add phosphated iron-based nanocrystalline powder, but all other steps and parameters are the same.

[0049] The magnetic cores prepared in Examples 1-5 and Comparative Example 1 were subjected to performance tests. The saturation magnetic flux density (mT) at 25°C, the saturation magnetic flux density (mT) at 100°C, the initial permeability at 25°C, and the Curie temperature (°C) were measured respectively. The test results are shown in Table 1.

[0050] Table 1

[0051]

[0052] As shown in Table 1, compared with Comparative Example 1, the magnetic cores prepared in Examples 1-5 have higher saturation magnetic flux density (25℃ and 100℃) and initial permeability. At the same time, the Curie temperature of the magnetic cores prepared in Examples 1-5 is also significantly improved, resulting in better high-temperature stability.

[0053] Example 6

[0054] This embodiment provides a preliminary inductor 2, which is manufactured through the following steps:

[0055] Step S1: Coil fabrication: The horizontal double-slot bobbin is automatically fed onto the winding machine chuck via a vibratory feeder. Then, 0.13mm diameter enameled wire is automatically wound onto the bobbin, with 80 turns in each slot, to obtain the coil. The coil is then automatically conveyed onto a belt via a vibratory feeder. The coil is then first dipped in flux and then soldered using a clamp. The leads of the coil are soldered onto the pins to obtain a coil with leads.

[0056] Step S2: Preparation of inductor prototype 2: First, wrap the winding part of the coil with leads with Marlboro tape to obtain an insulated coil; then, assemble the magnetic core obtained in Example 4 onto the insulated coil, rotate the magnetic core, and wrap Marlboro tape around the magnetic core to obtain inductor prototype 2; after testing, the inductance coefficient of the inductor prototype 2 obtained in this example is 4500.

[0057] Comparative Example 2

[0058] Compared with Example 6, this comparative example only replaces "the magnetic core obtained in Example 4" with "the magnetic core obtained in Comparative Example 1", and all other steps and parameters are the same; after testing, the inductance coefficient of the inductor prototype 2 obtained in this comparative example is 3500.

[0059] As can be seen from the inductance coefficients of the inductor prototype 2 obtained in Example 6 and Comparative Example 2, the magnetic core prepared using the present invention can improve the inductance of the inductor.

[0060] Example 7

[0061] This embodiment provides a manufacturing process for a common-mode inductor, including the following steps:

[0062] Step S3, Impregnation: as follows Figures 1-5 As shown, the inductor prototype 2 prepared in Example 6 is first neatly arranged with its pins facing down in the convex groove 101 of the tray fixture 1. The varnish-impregnating tray 3 is then placed upside down on the tray fixture 1 filled with the inductor prototype 2. After flipping the tray fixture 1 and the varnish-impregnating tray 3, the tray fixture 1 above the varnish-impregnating tray 3 is removed. At this time, all the pins of the inductor prototype 2 are placed upwards and neatly in the varnish-impregnating tray 3. Then, the varnish-impregnating tray 3 is transferred to the varnish-impregnating tank 4. The bottom surface of the varnish-impregnating tray 3 is placed on the top of the pad 402. The insulating liquid 401 passes through the through hole 301 on the bottom surface of the varnish-impregnating tray 3. By controlling the liquid level of the insulating liquid 401, the liquid level of the insulating liquid 401 is made to submerge the coil of the inductor prototype 2 without contacting the pins. The insulating liquid 401 is obtained by mixing insulating varnish and diluent in a mass ratio of 1:1. The specific gravity of the insulating liquid 401 is 0.905. The immersion is carried out at normal pressure for 15 minutes.

[0063] Step S4, Post-processing: After impregnation with varnish, air dry for 20 minutes, then bake in an oven at 100℃ for 2.5 hours to dry the insulating liquid 401; finally, use a lead-aligning fixture to adjust the lead spacing that has been deformed by heat to within the acceptable range, thus obtaining the finished common mode inductor.

[0064] Example 8

[0065] This embodiment provides a manufacturing process for a common-mode inductor, including the following steps:

[0066] Step S3, Impregnation: as follows Figures 1-5As shown, the inductor prototype 2 prepared in Example 6 is first neatly arranged with its pins facing down in the convex groove 101 of the tray fixture 1. The varnish-impregnating tray 3 is then placed upside down on the tray fixture 1 filled with the inductor prototype 2. After flipping the tray fixture 1 and the varnish-impregnating tray 3, the tray fixture 1 above the varnish-impregnating tray 3 is removed. At this time, all the pins of the inductor prototype 2 are placed upwards and neatly in the varnish-impregnating tray 3. Then, the varnish-impregnating tray 3 is transferred to the varnish-impregnating tank 4. The bottom surface of the varnish-impregnating tray 3 is placed on the top of the pad 402. The insulating liquid 401 passes through the through hole 301 on the bottom surface of the varnish-impregnating tray 3. By controlling the liquid level of the insulating liquid 401, the liquid level of the insulating liquid 401 is made to submerge the coil of the inductor prototype 2 without contacting the pins. The insulating liquid 401 is obtained by mixing insulating varnish and diluent in a mass ratio of 1:1. The specific gravity of the insulating liquid 401 is 0.915. The immersion is carried out at normal pressure for 13 minutes.

[0067] Step S4, Post-processing: After impregnation with varnish, air dry for 20 minutes, then bake in an oven at 120℃ for 2.5 hours to dry the insulating liquid 401; finally, use a lead-aligning fixture to adjust the lead spacing that has been deformed by heat to within the acceptable range, thus obtaining the finished common mode inductor.

[0068] Example 9

[0069] This embodiment provides a manufacturing process for a common-mode inductor, including the following steps:

[0070] Step S3, Impregnation: as follows Figures 1-5 As shown, the inductor prototype 2 prepared in Example 6 is first neatly arranged with its pins facing down in the convex groove 101 of the tray fixture 1. The varnish-impregnating tray 3 is then placed upside down on the tray fixture 1 filled with the inductor prototype 2. After flipping the tray fixture 1 and the varnish-impregnating tray 3, the tray fixture 1 above the varnish-impregnating tray 3 is removed. At this time, all the pins of the inductor prototype 2 are placed upwards and neatly in the varnish-impregnating tray 3. Then, the varnish-impregnating tray 3 is transferred to the varnish-impregnating tank 4. The bottom surface of the varnish-impregnating tray 3 is placed on the top of the pad 402. The insulating liquid 401 passes through the through hole 301 on the bottom surface of the varnish-impregnating tray 3. By controlling the liquid level of the insulating liquid 401, the liquid level of the insulating liquid 401 is made to submerge the coil of the inductor prototype 2 without contacting the pins. The insulating liquid 401 is obtained by mixing insulating varnish and diluent in a mass ratio of 1:1. The specific gravity of the insulating liquid 401 is 0.925. The immersion is carried out at normal pressure for 10 minutes.

[0071] Step S4, Post-processing: After impregnation with varnish, air dry for 20 minutes, then bake in an oven at 140℃ for 2.5 hours to dry the insulating liquid 401; finally, use a lead-aligning fixture to adjust the lead spacing that has been deformed by heat to within the acceptable range, thus obtaining the finished common mode inductor.

[0072] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0073] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A manufacturing process for a common-mode inductor, characterized in that, Includes the following steps: Step S1: Load the bobbin onto the winding machine chuck, then automatically wind the enameled wire onto the bobbin to obtain a coil; solder the coil leads to the pins to obtain a coil with leads. Step S2: First, wrap the winding part of the coil with leads with Mala tape to obtain an insulated coil; then assemble the magnetic core onto the insulated coil, rotate the magnetic core, wrap Mala tape around the magnetic core, and after the inductance is tested and found to be qualified, the inductor prototype (2) is obtained. Step S3: First, neatly place the inductor blanks (2) with the pins facing down in the tray fixture (1). Then, invert the varnish-soaking tray (3) onto the tray fixture (1) which is full of inductor blanks (2). After flipping the tray fixture (1) and the varnish-soaking tray (3) over, remove the tray fixture (1) above the varnish-soaking tray (3). Then, transfer the varnish-soaking tray (3) to the varnish-soaking tank (4). Control the liquid level of the insulating liquid (401) to submerge the coil without contacting the pins. Soak at normal pressure for 10-15 minutes. Step S4: After impregnation with paint, air dry for 20 minutes, then bake in an oven; finally, adjust the pin spacing using a lead-aligning fixture to obtain the finished common-mode inductor. The magnetic core is prepared by the following steps: Fe2O3, MnO and ZnO were mixed in a molar ratio of 11:7:2 and pre-calcined in air to obtain a pre-calcined raw material. SiO2, CaO, Nb2O5 and CoO were then added to the pre-calcined raw material and pulverized using a sand mill. Phosphated iron-based nanocrystalline powder was then added and mixed. Silicone resin was then added and mixed and granulated. The mixture was then placed into a mold and pressed into shape. After molding, the mixture was sintered in a nitrogen atmosphere at 1000℃ for 3 hours. Finally, the interface was mirror-polished to obtain the magnetic core. The phosphated iron-based nanocrystalline powder contains 0.03-0.05 wt% phosphoric acid, with the remainder being iron-based nanocrystalline powder; The amount of the phosphated iron-based nanocrystalline powder used is 3-5% of the total weight of the pre-calcined raw materials.

2. The manufacturing process of a common-mode inductor according to claim 1, characterized in that, The frame is a horizontal double-slot frame, and the number of winding coils and wire diameter of each slot are the same.

3. The manufacturing process of a common-mode inductor according to claim 1, characterized in that, The insulating liquid (401) is obtained by mixing insulating varnish and diluent at a mass ratio of 1:1, and the specific gravity of the insulating liquid (401) is 0.905-0.

925.

4. The manufacturing process of a common-mode inductor according to claim 1, characterized in that, The oven temperature is set to 100-140℃, and the baking time is 2.5 hours.

5. The manufacturing process of a common-mode inductor according to claim 1, characterized in that, The pre-firing temperature is 900℃ and the pre-firing time is 2 hours.

6. The manufacturing process of a common-mode inductor according to claim 1, characterized in that, The amounts of SiO2, CaO, Nb2O5 and CoO are 0.008%, 0.07%, 0.05% and 0.02% of the total weight of the pre-calcined raw materials, respectively.

7. The manufacturing process of a common-mode inductor according to claim 1, characterized in that, The amount of silicone resin used is 3-5% of the total weight of the pre-fired raw materials.

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