Flat wire EMI inductor

Abstract

The utility model discloses a kind of flat wire EMI inductors, by preformed butterfly wing U-shaped magnetic core, butterfly sheet body magnetic core and winding coil cooperation base assembly molding, wherein winding coil preformed state is three turns above and annular winding of turn gap zero, a pair of butterfly wing U-shaped magnetic core and winding coil molding preassembly, a pair of preassembly body opposite clamping butterfly sheet body magnetic core and bonding into an organic whole, two winding coils all free end linear extension in same direction, bonding body with all free end penetrates the preset slot of base and bonding assembly with base.The inductor is based on the coil preform of flat wire and the shape of magnetic core and assembly structure by optimization, effectively solve the production problem of EMI inductor made of flat wire, and obtain the EMI filter inductance of high-voltage AC input end, while effectively improve the current-carrying capacity of inductor device, boost its application in new energy charging pile and photovoltaic industry.

Description

Technical Field

[0001] This utility model relates to an inductor, and more particularly to a flat wire EMI inductor, 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] Currently, the common structure of inductors in the industry is a fully enclosed device with a magnetic core wrapped around a metal wire core. However, as the circuit is used for a long time, the inductor gradually accumulates heat and rises in temperature. Furthermore, the miniaturization of the core size leads to a weakening of the current withstand capability of the inductor, which affects the performance of the inductor. Therefore, increasing the density of the metal wire core and the partially open design of the magnetic core has become a technical direction for breakthroughs in the performance of inductor products. Summary of the Invention

[0004] The purpose of this invention is to propose a flat-wire EMI inductor, which aims to optimize the EMI interference of inductor devices in SMPS circuits.

[0005] The technical solution of this utility model to achieve the above-mentioned objective is: a flat-wire EMI inductor, which is assembled from a pre-formed butterfly-wing U-shaped magnetic core, a butterfly-shaped sheet magnetic core and a wound coil with a base. The wound coil is pre-formed as a ring-shaped winding with more than three turns and zero turn gap. A pair of butterfly-wing U-shaped magnetic cores and the wound coil are pre-assembled into a pre-assembled body. The pair of pre-assembled bodies sandwich the butterfly-shaped sheet magnetic core and are bonded together. All free ends of the two wound coils extend linearly in the same direction. The adhesive body penetrates the preset slot of the base with all free ends and is bonded to the base.

[0006] Furthermore, the winding coil is formed by spirally winding a flat wire in its own transverse direction, and the two free ends of the flat wire are bent in the same direction and extended linearly at a distance from each other.

[0007] Furthermore, each free end of the wound coil is partially stripped of varnish and soldered to form electrode pads.

[0008] Furthermore, a positioning post is formed in the middle of the butterfly-wing U-shaped magnetic core, and a fan-shaped annular base with a thickness lower than the height of the positioning post is formed on each radial side of the positioning post. A square outer and concave inner arc-shaped frame is formed on the outer side of each fan-shaped annular base. The back surfaces of the positioning post, the fan-shaped annular base and the frame are flat, and the positioning post is flush with the front surface of the frame. An open-loop cavity is formed between the positioning post and the frame.

[0009] Furthermore, the butterfly-shaped sheet magnetic core is a sheet of equal thickness with an outer contour consistent with the butterfly wing U-shaped magnetic core and flat on both sides.

[0010] Furthermore, both the butterfly-wing U-shaped magnetic core and the butterfly-shaped sheet magnetic core are solidified blocks formed by cold pressing powder material based on a customized mold and treated with epoxy spraying insulation.

[0011] Furthermore, in the pre-assembled assembly, a strip-shaped pad is attached to the frame surface where the butterfly wing U-shaped magnetic core meets the butterfly plate magnetic core. Both the pad and the base are glass fiber molded bodies. The base has four preset slots that penetrate its own thickness direction. The position of each preset slot corresponds to the four free ends of the two winding coils in the assembled state. The exposed part of the winding coil on the underside of the base is the electrode pad of the surface solder.

[0012] Compared with the prior art, the advantages of this inductor are reflected in the following aspects: by optimizing the coil prefabrication and core shape and assembly structure based on flat wire, the production problem of using flat wire to wind coils and assemble EMI inductors is effectively solved, and EMI filter inductors for high voltage AC input terminals are obtained. At the same time, the current withstand capability of inductor devices is effectively improved, which promotes their application in new energy charging piles and photovoltaic industries. Attached Figure Description

[0013] Figure 1 This is a three-dimensional structural diagram of the butterfly-wing U-shaped magnetic core in the flat-wire EMI inductor of this utility model.

[0014] Figure 2 This is a schematic diagram of the prefabrication of the wound coil in the flat wire EMI inductor of this utility model.

[0015] Figure 3 This is a three-dimensional structural diagram of the disc-shaped magnetic core in the flat-wire EMI inductor of this utility model.

[0016] Figure 4 This is a schematic diagram illustrating the assembly evolution of the flat-wire EMI inductor of this utility model. Detailed Implementation

[0017] 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.

[0018] This invention proposes a flat-wire EMI inductor, aiming to improve the performance of inductor devices and reduce their EMI interference to the applied circuits. For example... Figures 1 to 4 As shown, the basic structure of this inductor is assembled from a pre-formed butterfly-wing U-shaped magnetic core 1, a butterfly-shaped sheet magnetic core 2, and a wound coil 3, along with a base 5. The wound coil, in its pre-formed state, is a ring-shaped winding with three or more turns and zero inter-turn gaps. A pair of butterfly-wing U-shaped magnetic cores and the wound coils are pre-assembled into a single unit A. This pre-assembled unit sandwiches the butterfly-shaped sheet magnetic cores and is bonded together. All free ends of the two wound coils extend linearly in the same direction. The bonding unit penetrates the pre-set slots in the base with all its free ends and is bonded to the base. Because the wound coil is nested entirely within the butterfly-wing U-shaped magnetic core, and the base provides auxiliary shaping for the wound coil, the assembly structure of the wound coil and the butterfly-wing U-shaped magnetic core is more stable.

[0019] Depend on Figure 4 As shown at the bottom, this new EMI inductor features a structure with partially exposed magnetic core and partially exposed coil, significantly increasing the core area. This improves the inductor's current handling capability and heat dissipation during operation. Furthermore, the assembly process is greatly simplified, avoiding additional damage to the finished inductor caused by high-temperature, high-pressure manufacturing processes.

[0020] Looking at it in more detail, such as Figure 2 In the prefabricated state shown, the wound coil 3 is formed by spirally winding a flat wire laterally. Specifically, the flat wire is spirally wound around a vertical line perpendicular to its own plane on its outer side in the width direction, gradually forming a ring 31 with a built-in circular hole 34, with the two free ends 32 of the flat wire bent in the same direction and extending linearly at a distance. As long as the distance between the two free ends is fixed during inductor assembly, the main body of the wound coil will not change. Specifically, this flat wire is an enameled copper flat wire, which requires electrical connection as the basis for the inductor to connect to the PCB. Therefore, during the prefabrication process, a small section of the free end undergoes partial enameling removal to expose the copper surface, followed by electroplating soldering to obtain electrode pads 33.

[0021] like Figure 1As shown, a positioning post 11 is formed in the middle of the butterfly-shaped U-shaped magnetic core 1, and a fan-shaped annular base 12 with a thickness lower than the height of the positioning post is formed on each radial side of the positioning post. Each fan-shaped annular base has an outer square and inner concave arc-shaped frame 13 formed on its outer side. Visually, the back surfaces of the positioning post, fan-shaped annular base, and frame are flat, and the front surfaces of the positioning post and frame are flush, facilitating the fit of the butterfly-shaped magnetic core during assembly (the thickness of the mounting pads described later is negligible). An open-loop cavity is formed between the positioning post and the frame for the winding coil to be embedded within. And as... Figure 3 As shown, the butterfly-shaped sheet magnetic core 2 is a sheet of uniform thickness with an outer contour consistent with the butterfly wing U-shaped magnetic core 1 and flat on both sides. Its main function is to isolate the mutual interference between the two sides of the core in a dual-inductor integrated device. Furthermore, both the aforementioned butterfly wing U-shaped magnetic core and the butterfly-shaped sheet magnetic core are solidified blocks formed by cold pressing powder material using a custom mold and treated with epoxy spray coating insulation, possessing the characteristics of being mass-produced and reusable for assembly.

[0022] Combination Figure 4 In the assembly process shown, a strip-shaped pad 4 is attached to the surface of the frame 13 where the butterfly-shaped U-shaped magnetic core meets the butterfly-shaped sheet magnetic core. Both the pad 4 and the base 5 are made of glass fiber, providing good external insulation. Furthermore, the base has four pre-set slots 51 penetrating its own thickness direction, with the position of each slot corresponding to the four free ends of the two wound coils in the assembled state. The length of the stripped solder of the wound coil also depends on the amount of the wound coil exposed on the underside of the base after assembly; preferably, only the electrode pads with exposed solder surfaces are exposed. From the complete process illustrated in the preferred embodiment: firstly, wound coils are prefabricated in batches using flat wire, and then the free ends of the formed coils undergo uniform stripping and solder plating treatments. Simultaneously, two different shaped magnetic cores are prefabricated. Then, the butterfly-wing U-shaped magnetic core and the wound coil are grouped one-to-one and pre-assembled into a pre-assembled body A by embedding the coil. Optionally, a spacer can be attached to the edge of the butterfly-wing U-shaped magnetic core to enclose the coil on both sides, preventing EMI lateral leakage from affecting surrounding components. Next, another completed pre-assembled body A is taken and rotated 180° so that the coil portions of the pair of pre-assembled bodies are facing each other, and the butterfly-shaped magnetic core is sandwiched between the sides, resulting in a primary assembly B. Since the wound coil lacks a strong limiting structure and can only rotate slightly around the positioning post, to ensure the structural stability of the finished device, it is aligned and assembled with the base (all free ends are inserted into pre-set slots). Adhesive is applied to all contact points of the two types of magnetic cores, spacers, and the base, and the entire assembly is pressurized and cured to obtain the finished EMI inductor C.

[0023] In summary, the preferred embodiment of the flat wire EMI inductor of this utility model is described in detail above. Compared with the prior art, its technical effects are as follows: by optimizing the coil prefabrication and core shape and assembly structure based on flat wire, the production problem of using flat wire to wind coils and assemble EMI inductors is effectively solved, and EMI filter inductors with high voltage AC input are obtained. At the same time, the current withstand capability of inductor devices is effectively improved, which promotes its application in new energy charging piles and photovoltaic industries.

[0024] 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 flat-wire EMI inductor, characterized in that: The inductor is assembled from a pre-formed butterfly-wing U-shaped magnetic core, a butterfly-shaped sheet magnetic core, and a wound coil with a base. The wound coil is pre-formed as a ring with more than three turns and zero gap between turns. A pair of butterfly-wing U-shaped magnetic cores and the wound coil are pre-assembled together. The pair of pre-assembled bodies sandwich the butterfly-shaped sheet magnetic core and are bonded together. All free ends of the two wound coils extend linearly in the same direction. The adhesive body penetrates the preset slots of the base with all free ends and is bonded to the base.

2. The flat-wire EMI inductor according to claim 1, characterized in that: The winding coil is formed by spirally winding a flat wire in its own transverse direction, with the two free ends of the flat wire bent in the same direction and extended linearly at a distance from each other.

3. The flat-wire EMI inductor according to claim 1 or 2, characterized in that: Each free end of the wound coil is partially stripped of its enamel and soldered to form electrode pads.

4. The flat-wire EMI inductor according to claim 1, characterized in that: The butterfly-wing U-shaped magnetic core has a positioning post formed in the middle, and a fan-shaped annular base with a thickness lower than the height of the positioning post is formed on each radial side of the positioning post. Each fan-shaped annular base has an outer square and inner concave arc-shaped frame formed on the outer side. The back surface of the positioning post, the fan-shaped annular base and the frame are flat, and the front surface of the positioning post is flush with the front surface of the frame. An open-loop cavity is formed between the positioning post and the frame.

5. The flat-wire EMI inductor according to claim 1, characterized in that: The butterfly-shaped sheet magnetic core is a sheet of equal thickness with an outer contour consistent with the butterfly wing U-shaped magnetic core and flat on both sides.

6. The flat-wire EMI inductor according to claim 1, characterized in that: Both the butterfly-wing U-shaped magnetic core and the butterfly-shaped sheet magnetic core are solidified blocks formed by cold pressing powder material based on a customized mold and treated with epoxy spraying insulation.

7. The flat-wire EMI inductor according to claim 1, characterized in that: In the pre-assembled assembly, a strip-shaped pad is attached to the frame surface where the butterfly wing U-shaped magnetic core meets the butterfly plate magnetic core. Both the pad and the base are made of glass fiber. The base has four preset slots that penetrate its own thickness direction. The position of each preset slot corresponds to the four free ends of the two winding coils in the assembled state. The exposed part of the winding coil on the underside of the base is the electrode pad of the surface solder.

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