Hot-pressing common-mode inductor

Abstract

The utility model discloses a hot-pressing common-mode inductor, which is formed by assembling a T-shaped magnetic core, a box-type magnetic core, an electrode frame and a duplex winding coil which are prefabricated, more than two groups of mutually separated electrode teeth are formed on the electrode frame, four end parts of the duplex winding coil are welded with any group of electrode teeth, and the other end parts of the duplex winding coil are welded with the T-shaped magnetic core, the box-type magnetic core, the electrode frame and the duplex winding coil. The T-shaped magnetic core is connected to the double-winding coil in a penetrating mode from bottom to top, the box-type magnetic core and the T-shaped magnetic core are formed into a whole in a hot press mode, the double-winding coil and part of the electrode teeth are fully wrapped in the box-type magnetic core and the T-shaped magnetic core, and the electrode teeth are exposed, cut and bent to form pins. According to the inductor, the structure of the magnetic core is optimized, the T-shaped magnetic core and the box-type magnetic core are adopted to assemble and wrap the double-winding coil, the possibility of short circuit caused by damage between coil layers is greatly reduced, and the product yield is improved; and the molded structure of the double-winding coil is beneficial to improving the coupling coefficient k to be greater than 97%, and is beneficial to the application of an SEPIC circuit in an automobile headlight.

Description

Technical Field

[0001] This utility model relates to an inductor device, and more particularly to a hot-pressed common-mode inductor with high coupling rate for use in automotive headlights, belonging to the field of basic electronic components technology. Background Technology

[0002] Inductors are one of the most commonly used components in electronic devices, widely used in various circuits to perform functions such as filtering, energy storage, matching, and resonance. With the increasing miniaturization and portability of electronic products, and the high-density assembly of components, inductor components have developed rapidly. Furthermore, considering electromagnetic compatibility, the ability of electronic products to resist electromagnetic interference has become a basic design requirement, thus increasing the demand for and application of inductors.

[0003] In automotive electronics applications, common-mode inductors are a common inductor structure, consisting of two sets of coil windings within a single magnetic core with four leads on one side. In SEPIC circuit applications, improving the coupling coefficient between the two coil windings is a key factor in enhancing performance. However, existing common-mode inductors are prone to short-circuiting during manufacturing due to powder being extruded between coil layers, potentially causing defects during thermoforming. Therefore, improving coupling efficiency and yield in the structural design of common-mode inductors has become a major focus of industry research. Summary of the Invention

[0004] The purpose of this invention is to propose a hot-pressed common-mode inductor, which aims to improve the coupling performance of inductor devices and increase manufacturing yield and efficiency.

[0005] The technical solution of this utility model to achieve the above-mentioned objective is: a hot-pressed common-mode inductor, which is assembled from a prefabricated T-shaped magnetic core, a box-shaped magnetic core, an electrode frame, and a dual-winding coil. The electrode frame is formed with two or more sets of mutually separated electrode teeth. The four ends of the dual-winding coil are welded to any set of electrode teeth. The T-shaped magnetic core passes through the dual-winding coil from bottom to top. The box-shaped magnetic core and the T-shaped magnetic core are hot-pressed into one piece and fully enclose the dual-winding coil and part of the electrode teeth therein. The exposed ends of the electrode teeth are cut and bent into leads.

[0006] Furthermore, the electrode frame is a stamped conductor sheet, wherein each set of electrode teeth is formed into two Y-shaped plates that are open and spaced apart from each other.

[0007] Furthermore, the double-winding coil is a tubular body composed of two mutually insulated copper round wires wound in the same direction and having an inner and outer double layer composite structure. The two ends of one copper round wire intersect on one side of the bottom of the tubular body and extend in opposite directions, while the two ends of the other copper round wire intersect on the other side of the bottom of the tubular body and extend in opposite directions.

[0008] Furthermore, both the T-shaped magnetic core and the box-shaped magnetic core are cold-pressed bodies made of powder material based on a customized mold.

[0009] Furthermore, the T-shaped magnetic core and the box-type magnetic core are assembled and hot-pressed onto the dual-winding coil and the electrode frame in a spot-welded state, and the hot-pressed package is cut from the electrode frame.

[0010] Furthermore, the bottom of the thermo-pressed package has at least two spaced grooves, and the leads formed by bending the electrode teeth fall into the grooves.

[0011] Compared with the prior art, the advantages of the inductor of this utility model are reflected in the following: by optimizing the core structure, using T-shaped core and box-type core to assemble and wrap the double-winding coil, the possibility of short circuit caused by interlayer damage of the coil is greatly reduced, and the product yield is improved; moreover, the forming structure of the double-winding coil is conducive to improving the coupling coefficient k>97%. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the finished inductor of this utility model.

[0013] Figure 2 This is a schematic diagram of the T-shaped magnetic core in a preferred embodiment of the inductor of this utility model.

[0014] Figure 3 This is a schematic diagram of the structure of the box-type magnetic core in a preferred embodiment of the inductor of this utility model.

[0015] Figure 4 This is a schematic diagram of the structure of the dual-winding coil in a preferred embodiment of the inductor of this utility model.

[0016] Figure 5 This is a schematic diagram of the electrode frame in a preferred embodiment of the inductor of this utility model.

[0017] Figure 6 This is a schematic diagram illustrating the evolution of the shape of the inductor assembly and finished product manufacturing of this utility model. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0019] This invention proposes a hot-pressed common-mode inductor, aiming to improve the coupling performance of inductor devices while simultaneously increasing production efficiency and yield. For example... Figures 1 to 6As shown, the inductor A has a cube-shaped appearance with several leads distributed at the bottom. Its basic structure is assembled from prefabricated T-shaped magnetic cores 1, box-shaped magnetic cores 2, electrode frames 4, and dual-winding coils 3. Although the common-mode inductor is actually a single device in practical applications, due to the mass production process, the part used to form the leads comes from the multi-station composite electrode frame. Here, the electrode frame is formed with two or more sets of mutually separated electrode teeth 41, and the four ends of each prefabricated dual-winding coil are welded to any set of electrode teeth. After the electrode frame and the corresponding number of dual-winding coils have been welded and cooled, the T-shaped magnetic cores 1 are inserted into the dual-winding coils from bottom to top, and the box-shaped magnetic cores are hot-pressed together with the T-shaped magnetic cores to form a whole, fully enclosing the dual-winding coils and part of the electrode teeth. As the basis for the inductor to be connected to the PCB, the exposed electrode teeth are cut and bent into the first pin A1 and the second pin A2; at the same time, due to the structural strength of the thermo-pressed package, the bending and wrapping of these two pins can prevent the electrode teeth embedded in the thermo-pressed package from detaching from the dual-winding coil.

[0020] For design considerations of multi-unit integration and mass production, the above-mentioned two types of magnetic cores, electrode frames, and dual-winding coils can all be prefabricated and reused in batches. Based on the overview of this technical solution and the illustrations of preferred embodiments, the detailed features of each functional component of this inductor also include: Figure 2 The T-shaped magnetic core 1 shown has a square base 11 and a vertically erected central post 12. During assembly, the central post 12 passes through the central cavity of the double-winding coil, while the base 11 rests against the bottom of the double-winding coil. Figure 3 The box-shaped magnetic core 2 shown (or what is known in the industry as a U-shaped magnetic core) has an overall outer contour that matches the chassis contour of the T-shaped magnetic core and has uniform sidewalls. Its inner cavity 21 is suitable for completely enclosing the dual-winding coil 3. Both types of magnetic cores are assemblies prefabricated based on powder materials and custom molds. Specifically, they use one or more mixtures of Fe-based / FeSiCr / FeSiAl / FeNi / FeSi / amorphous / nanocrystalline materials, and add one of epoxy resin, silicone resin or acrylic resin, stir evenly, and then inject into a custom mold designed to conform to the shape of the device for cold pressing.

[0021] like Figure 4The dual-winding coil 3 shown is a tubular structure composed of two mutually insulated copper round wires wound in the same direction and with an inner and outer double layer. As shown in the winding diagram of the second copper round wire 3b, one end is spirally wound upwards in a clockwise direction, and after slightly reducing the radius at a predetermined height, it spirally wound downwards in the same direction. The other end then crosses at the bottom and extends a distance in the opposite direction. Similarly, the winding shape of the first copper round wire 3a is similar. In actual production, the two copper round wires are wound synchronously and nested into a tubular structure, with the intersection of the two ends of each copper round wire corresponding to the radial sides of the bottom of the tubular structure. Moreover, the insulation gap between the two copper round wires is close to zero, which is beneficial for improving the coupling performance of this type of common-mode inductor. Simulation tests show that the coupling coefficient k is greater than 0.97.

[0022] like Figure 5 The electrode frame 4 shown is a stamped conductor sheet. In the illustrated embodiment, there are three sets of electrode teeth 4a, 4b, and 4c arranged in sequence and separated by a distance. Based on the operability of the hot-pressing encapsulation mold, the electrode frame can be appropriately increased or decreased by 1 to 2 sets of electrode teeth. Each set of electrode teeth is formed into two Y-shaped plates 41 with open and spaced apart.

[0023] like Figure 6 As shown in the diagram, the complete manufacturing process of the preferred embodiment (three sets) of the inductor is as follows: First, the T-shaped magnetic core, the box-shaped magnetic core, the dual-winding coil, and the electrode frame are prefabricated and sufficient spare parts are prepared. Then, according to the number of electrode thread groups, the corresponding number of dual-winding coils 3 are selected and spot-welded onto the electrode frame 4 one by one. Figure 6 (As shown in section B). After the solder joints have solidified, insert the center post 12 of the T-shaped magnetic core into the middle of the double-winding coil 3 from bottom to top. Figure 6 (As shown in section C), then the box-type magnetic core 2 covers the double-winding coil 3 and is flush-fitted with the base 11 of the T-shaped magnetic core. Then it is transferred into a hot-pressing mold to press the two magnetic core parts together as one unit. Figure 6 (As shown in section D). The parameters for thermoforming are: molding temperature 100-200℃, molding pressure 4-12 Tons / cm², and molding time 30-180 seconds. After the thermoformed package has cooled and solidified, the exposed electrode teeth are cut to obtain the final semi-finished product. Figure 6 As shown in section E), the exposed portion is finally bent against the edge of the thermopressed package to form a lead. Then... Figure 1 As shown, the bottom of the thermo-pressed package has at least two spaced grooves, and the leads formed by bending the electrode teeth can fall into the grooves, further reducing the space occupied by the assembly of the device.

[0024] In summary, the preferred embodiment of the hot-pressed common-mode inductor of this utility model shows that, compared with the prior art, its technical effects are as follows: by optimizing the core structure and using T-shaped cores and box-type cores to assemble and wrap the dual-winding coil, the possibility of short circuits caused by interlayer damage of the coil is greatly reduced, and the product yield is improved; moreover, the forming structure of the dual-winding coil is conducive to improving the coupling coefficient k>97%.

[0025] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this application should be included within the protection scope of this application.

Claims

1. A hot-pressing common-mode inductor, characterized by: The electrode frame is a stamping formed conductor sheet, wherein each group of electrode tooth is shaped as two Y-shaped pole plates opposite to each other with open space.

2. The hot-press co-molded inductor of claim 1, wherein: The double-winding coil is a tubular body which is double-layered and compounded by two copper round wires which are mutually insulated and co-wound in the same direction, and the two ends of one copper round wire intersect at one side of the bottom of the tubular body and extend in opposite directions, and the two ends of the other copper round wire intersect at the other side of the bottom of the tubular body and extend in opposite directions.

3. The hot-press co-molded inductor of claim 1, wherein: The T-shaped magnetic core and the box-shaped magnetic core are both cold-pressed bodies based on customized molds.

4. The hot-press co-molded inductor of claim 1, wherein: The T-shaped magnetic core and the box-shaped magnetic core are assembled and hot-pressed in the state of spot welding of the double-winding coil and the electrode frame, and the hot-pressed packaging body is cut from the electrode frame.

5. The hot-press co-molded inductor of claim 1, wherein: The bottom of the hot-pressed packaging body is shaped with at least two recesses which are mutually separated, and the pins shaped by bending the electrode tooth fall into the recesses.

6. The hot-press co-molded inductor of claim 5, wherein: ​

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