A winding type patch terminal common mode inductor

Abstract

The application discloses a winding type patch terminal common mode inductor, which comprises a magnetic core, a wire, a terminal conductive plate and a welding part. The wire is wound on the magnetic core, and the end of the wire has an exposed part with a wire core exposed. The terminal conductive plate has a pressing frame with a hole and a notch corresponding to the pressing frame. The pressing frame tightly presses the end of the wire against the outer surface of the end plate of the magnetic core in the notch. The wire core at the position of the exposed part is exposed by the hole. The inner frame and the outer frame on both sides of the hole of the pressing frame are respectively pressed against the insulating layers on both sides of the exposed part. The welding part covers the exposed part and the pressing frame, so that the wire and the terminal conductive plate are electrically connected. In this way, the hole is arranged in the middle of the pressing frame. When the pressing frame tightly presses the wire, the frames on both sides of the pressing frame tightly press the wire. Meanwhile, the edges around the hole of the pressing frame can limit the welding part, inhibit the solder forming the welding part from spreading outward, improve the welding quality and reduce the waste of the solder.

Description

Technical Field

[0001] This invention relates to the field of electronic components, and more specifically to a wire-wound surface mount common mode inductor. Background Technology

[0002] In the field of electronic component manufacturing, the welding and fixing process between magnetic cores and wires is a core step in enabling various electromagnetic devices such as common-mode inductors, transformers, and chokes to achieve power conversion, signal transmission, and electromagnetic interference suppression. The welding quality directly determines the electrical performance, mechanical stability, and service life of the device, and is a key factor affecting the overall reliability of the electromagnetic device. Currently, the mainstream welding and fixing method in the industry mostly adopts a local electroplating process on the magnetic core body. Specifically, the end face of the magnetic core used for welding connection is plated with metals such as silver, nickel, or tin. The electroplating layer improves the conductivity and solderability of the magnetic core end face. Then, after removing the insulation layer of the enameled wire end, it is directly welded to the electroplated end face of the magnetic core, thereby achieving electrical connection and mechanical fixing between the magnetic core and the wire.

[0003] This traditional welding method, with its simple process, low operating threshold, lack of additional auxiliary tooling and fixtures, and high production efficiency, has been widely used in the production of low- and mid-range electromagnetic devices. However, after in-depth analysis of its actual application scenarios and long-term performance, it was found that this method has many obvious and insurmountable defects, which seriously restrict its application in high-end fields. First, the wires lack effective clamping and precise positioning mechanisms during the welding process. They are easily affected by factors such as soldering iron temperature, solder flow impact force, and operating techniques, resulting in positional displacement or loosening. This leads to problems such as cold solder joints, false solder joints, or poor contact, causing electromagnetic devices to experience malfunctions such as increased contact resistance, abnormal heating, and unstable signal transmission during operation. Secondly, when directly welding the wire ends to the electroplated end faces of the magnetic core, high temperatures (400-500℃) and high pressures (0.5-3N) are required to ensure a strong and secure weld. Therefore, the mechanical forces and thermal stresses during welding can easily cause irreversible plastic deformation of the copper wire. This not only reduces the mechanical strength and fatigue resistance of the copper wire itself, but also easily leads to wire breakage and solder joint detachment in long-term vibration and alternating hot and cold working environments, severely affecting the long-term stable operation of the device. Finally, the lack of effective constraint and guidance of the solder during welding can easily lead to disordered diffusion. This causes unnecessary waste of solder, increasing production costs. Furthermore, the diffused solder may cover non-welded areas of the magnetic core, affecting its magnetic properties. It also results in irregular and uneven solder joint formation, reducing the mechanical strength and electrical connection reliability of the solder joint. Ultimately, this affects the overall production yield and quality stability of the product, failing to meet the high reliability and stability requirements of automotive and industrial applications. Summary of the Invention

[0004] Based on this, and in response to the aforementioned technical problems, the present invention provides a wire-wound surface mount common mode inductor.

[0005] The objective of this invention can be achieved through the following technical solutions: A wire-wound surface mount common mode inductor includes: A magnetic core includes a core post and end plates connected to both ends of the core post; A terminal conductive plate has a main body plate attached to the surface of the end plate and a top plate integrally connected to the main body plate and attached to the top surface of the end plate. A conductor, comprising a conductive core and an insulating layer enclosing the core, the conductor being wound around the core post, and having an exposed portion of the core near its end. Welding section; The main body plate is provided with a pressure frame with holes and a notch corresponding to the pressure frame. The pressure frame presses and fixes the end of the wire to the surface of the end plate inside the notch. The wire core at the exposed part is exposed by the holes. The inner and outer frames of the pressure frame on both sides of the holes press against the insulation layer on both sides of the exposed part. The welded portion at least partially covers the exposed portion and the pressure frame, so that the wire is electrically connected to the terminal conductive plate.

[0006] By adopting the above technical solution, a terminal conductive plate is set on the end plate of the magnetic core. The main body of the terminal conductive plate has a pressure frame. When each end of the wire extends to the corresponding pressure frame, the wire end is pressed down by bending the pressure frame downwards. This achieves precise positioning and firm fixation of the wire, preventing wire displacement and loosening during welding, reducing the risk of wire detachment after welding, and ensuring the structural stability of the component during long-term use. Simultaneously, this clamping method eliminates the risk of wire detachment. Therefore, high temperature and high pressure are not required during welding; the welding part only needs to be melted and bonded to the exposed part and pressure frame at a relatively low temperature. No pressure is applied during welding, thus preventing irreversible plastic deformation of the copper wire and ensuring its stability. The integrity of the copper wire is protected, improving mechanical strength and fatigue resistance, and reducing the risk of wire breakage during long-term use. Furthermore, the clamping frame has openings, and the welded portion filled in the openings at least partially covers the exposed portion and the clamping frame. The perimeter of the clamping frame openings can restrict the welded portion, inhibiting the solder from spreading outward along the terminal conductive plate before the solder solidifies. This reduces solder material consumption, ensures regular solder joint formation, and further improves welding reliability, comprehensively solving various defects of traditional welding methods. In addition, this clamping method allows the wire to sink into the notch, which can reduce the height of the welded portion protruding from the surface of the terminal conductive plate, further reducing the length of the inductor and making it more suitable for the stringent requirements of compact circuit boards for component size.

[0007] In a specific embodiment of the present invention: the pressure frame is a rectangular frame, and the hole is a rectangular hole.

[0008] In a specific embodiment of the present invention: the insulation layer of the conductor located on the main body side outside the exposed portion is pressed by the inner frame, and the gap between the inner edge of the inner frame and the inner edge of the notch is greater than or equal to 0.1 mm.

[0009] In a specific embodiment of the present invention: the notch is located on the outer side of the main body plate, and the main body plate is formed with a pad supporting the wire on the inner side of the notch.

[0010] In a specific embodiment of the present invention: the top surface of the end plate has lead grooves, and each end of the wire passes through the corresponding lead groove. With this structure, when the magnetic core closes the magnetic circuit, the magnetic circuit path is regular and orderly, avoiding chaotic magnetic circuit distribution, increased magnetic resistance, and magnetic field leakage, ensuring stable and uniform transmission of magnetic flux, thereby effectively improving the electromagnetic conversion efficiency of the device and ensuring stable and reliable electrical performance; at the same time, it can ensure the structural strength of the end plate and prevent damage to the sides of the end plate when subjected to force.

[0011] In a specific embodiment of the present invention: the distance between the upper edge of the notch and the bottom plane edge of the lead wire groove is greater than or equal to 0.5 mm, and the distance between the inner edge of the pad and the width edge of the lead wire groove is greater than or equal to 0.15 mm.

[0012] In the above-described specific embodiments of the present invention, by setting a reasonable gap between the inner frame and the corresponding notch, and cooperating with the pad that is integrally connected with the main body plate, the shear force borne by the first transition part and the second transition part on the conductor can be significantly reduced, which can effectively avoid damage to the conductor insulation layer and reduce the risk of conductor breakage under stress.

[0013] In a specific embodiment of the present invention, the magnetic core is made of a magnetically permeable material. This effectively guides and concentrates the magnetic flux, reduces magnetic resistance, lowers magnetic leakage, improves electromagnetic conversion efficiency, and ensures the stable electrical performance of devices such as inductors and transformers.

[0014] In a specific embodiment of the present invention: the magnetic core further includes a cover plate covering the bottom surface of the two end plates. Thus, the cover plate, the two end plates, and the core post together constitute a closed magnetic circuit structure.

[0015] In a specific embodiment of the present invention: the welded portion completely covers the exposed portion.

[0016] In a specific embodiment of the present invention: the welding part uses solder paste material.

[0017] In summary, the wire-wound surface mount common mode inductor of this invention achieves precise fixing of wire ends, dispersion of welding stress, and suppression of solder diffusion through the rational design of the terminal conductive plate, pressure frame, notch, lead groove, and other structures. At the same time, it optimizes the magnetic circuit structure, reduces the size of the device, and protects the wires and magnetic core, thereby comprehensively improving the structural stability, electrical performance and reliability of the device, extending its service life and adapting to the needs of compact circuit boards. Attached Figure Description

[0018] The present invention will now be further described with reference to the accompanying drawings.

[0019] Figure 1 This is a schematic diagram of the structure of a wire-wound surface-mount common-mode inductor according to the present invention; Figure 2 This is a front view of the wire-wound surface-mount common-mode inductor of the present invention; Figure 3 This shows the pressure frame bending downwards to press the wire end; Figure 4 This shows the welded portion covering the exposed portion; Figure 5 This is a side view of the invention of a wire-wound surface-mount common-mode inductor. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figure 1 and Figure 2 As shown, the present invention is a wire-wound surface mount common mode inductor, including a magnetic core 10, a wire 20, a terminal conductive plate 30, and a soldering part 40.

[0022] The magnetic core 10 is made of a magnetically permeable material. For example, it may be one or more of ferrite, magnetic metal alloy, iron-silicon alloy, or soft magnetic materials to meet the operational requirements of magnetic devices. Using a magnetically permeable material effectively guides and concentrates magnetic flux, reduces magnetic reluctance, lowers magnetic leakage, improves electromagnetic conversion efficiency, and ensures stable electrical performance of devices such as inductors and transformers. In this embodiment, the magnetic core 10 includes a core post 11, end plates 12 connected to both ends of the core post 11, and a cover plate 13 covering the bottom surface of the end plates 12. The edges of the end plates 12 extend outwards, protruding beyond the edges of the core post 11. The cover plate 13, the two end plates 12, and the core post 11 together constitute a closed magnetic circuit structure.

[0023] In this embodiment, the magnetic core 10 has a length of 4.00 mm, a width of 2.50 mm, and a height of 2.50 mm.

[0024] In this embodiment, the core post 11 has a rectangular structure, which facilitates the stacking of coils composed of wires 20, thus providing more winding space. The rectangular structure also makes it easier to adjust the size during core forming, allowing for flexible control of the effective magnetic circuit area and thereby adjusting the magnetic saturation characteristics. Furthermore, the chamfered edges prevent damage to the enameled copper wire during assembly and make the manufacturing process easier.

[0025] The conductor 20 includes a conductive core and an insulating layer surrounding the core. The conductor 20 is wound around the core post 11 according to a preset rule. This preset rule could be selecting several coils with the same winding direction, or using an alternating direction design to reduce leakage inductance; or specifying the number of coil layers, the winding density of the coil, and the wire material used for the coil, etc. The conductor 20 has an exposed portion near its endpoint, exposing the core. A solder joint 40 covers the exposed portion to electrically connect the conductor 20 to the terminal conductive plate 30.

[0026] In this embodiment, the conductor 20 is made of copper enameled wire with a diameter of 0.05-0.08 mm. Copper is an excellent conductive material with low resistance. Using copper enameled wire as the conductor reduces the resistance of the inductor and improves current transmission efficiency. Copper also has good thermal conductivity, effectively dissipating heat from the conductor and preventing inductor performance degradation or damage due to excessively high temperatures. Furthermore, copper enameled wire can typically withstand high temperatures, making it suitable for applications in high-temperature environments, which is crucial for coil components that need to operate under high temperatures. Additionally, copper enameled wire has high corrosion resistance, resisting the erosion of some chemicals and extending the service life of the coil component.

[0027] In this embodiment, there are two wires 20. The two wires 20 are magnetically coupled but electrically insulated from each other. The middle part of each wire 20 is wound around the core post 11, and the two ends are respectively disposed on the outer surface of the corresponding end plate 12.

[0028] The thickness of the terminal conductive plate 30 is 0.1-0.2 mm. For example... Figure 1 , Figure 3 and Figure 4 As shown, in this embodiment, there are four terminal conductive plates 30, which are used to electrically connect to the four ends of the two wires 20 respectively. The four terminal conductive plates 30 are arranged in pairs on the corresponding end plates 12 at intervals. Specifically, the terminal conductive plates 30 are bonded to the end plates 12 using high-temperature resistant epoxy resin adhesive.

[0029] Figure 1 and Figure 3 As shown, in this embodiment, the terminal conductive plate 30 has a main body plate 301 attached to the outer surface of the end plate 12, and a top plate 302 integrally connected to the main body plate 301 and attached to the top surface of the end plate 12. The width of the top plate 302 is smaller than the width of the main body plate 301. A rectangular pressure frame 31 is cut and stamped into the main body plate 301, and after cutting and stamping, a notch 303 is formed on the main body plate 301 to expose the surface of the end plate 12 outward. The notch 303 is located on the outer side of the main body plate 301. The pressure frame 31 has a rectangular hole 32 in the middle.

[0030] Initially, the pressure frame 31 is perpendicular to the main body plate 301. The terminal conductive plate 30 is assembled onto the end plate 12. The ends of each wire 20 are pulled to the bottom of the corresponding pressure frame 31. Then, the pressure frame 31 is punched and bent so that its free end fits against the surface of the end plate 12, forming an arched structure in the middle to press and fix the ends of the wires 20 to the surface of the end plate 12, thereby achieving the positioning and firm fixation of the wires 20, avoiding the wires 20 from shifting or loosening during the welding process, and reducing the risk of the wires 20 falling off after welding, ensuring the structural stability of the components for long-term use. At the position where the wire 20 is directly opposite the hole 32, the above-mentioned exposed part is formed by laser stripping. This exposed part removes the insulation layer, allowing the wire core at the exposed part to be exposed by the hole 32; at the same time, the inner frame 332 and outer frame 331 of the pressure frame 31 on both sides of the hole 32 press against the insulation layer on both sides of the exposed part, preventing damage to the insulation layer of the remaining parts of the wire during laser stripping. Solder is filled into the hole 32 to form a welded portion 40. This welded portion 40 covers the exposed portion and is welded to the inner perimeter of the pressure frame. The perimeter of the hole 32 in the pressure frame 31 restricts the welded portion 40, preventing the solder from spreading outward along the terminal conductive plate 30 before it solidifies. Furthermore, both the wire 20 and the welded portion 40 are located within the notch, so that only a small portion of the welded portion 40 protrudes outside the hole, reducing the height of the welded portion protruding from the surface of the terminal conductive plate, resulting in a more compact overall structure. In addition, this clamping method only applies a pressure of 1-2N to the pressure frame during stamping and bending. This pressure does not act directly on the wire, and the wire is protected by the insulation layer, resulting in very small deformation of the wire under stress. This clamping method eliminates the risk of wire detachment. During welding, high temperature and high pressure are not required. The welding part only needs to be melted and bonded to the exposed part and the pressure frame at a relatively low temperature (up to 260°C). No pressure needs to be applied during welding, so it will not cause irreversible plastic deformation of the copper wire, which can ensure the integrity of the copper wire, improve mechanical strength and fatigue resistance, and reduce the risk of wire breakage during long-term use.

[0031] In this embodiment, a lead groove 14 is provided at the top of the end plate 12, located in the middle between the two terminal conductive plates 30, to guide and support the passage of the wires 20. Each end of the wire 20 passes through the corresponding lead groove 14. Since slotting the side of the end plate 12 can easily weaken the overall structural strength of the end plate 12, it can easily deform or be damaged when the end plate is under stress; slotting the bottom of the end plate 12 can easily cause magnetic circuit disorder. Therefore, compared with the structure of opening lead grooves on the side or bottom of the end plate 12, setting the lead groove on the top surface of the end plate can make the magnetic circuit regular and evenly distributed when the magnetic core forms a closed magnetic circuit, effectively avoiding magnetic circuit disorder, increased magnetic resistance and magnetic field leakage, ensuring stable and uniform transmission of magnetic flux, thereby improving the electromagnetic conversion efficiency of the device and ensuring its stable and reliable electrical performance; at the same time, it can ensure the structural strength of the end plate and prevent damage to the side of the end plate when it is under stress.

[0032] The conductor 20 has a first transition portion 21 and a second transition portion 22. The first transition portion 21 extends from the inner frame 332 to the main body plate 301. The second transition portion 22 extends from the main body plate 301 to the lead groove 14. Since the first transition portion 21 and the second transition portion 22 experience significant shear forces at their corresponding transition points, the conductor insulation layer is easily damaged, increasing the risk of conductor breakage. The gap 305 between the inner edge of the inner frame 332 and the inner edge of the notch 303 is greater than or equal to 0.1 mm, corresponding to the transition position of the first transition portion 21. This gap 305 effectively reduces the shear stress experienced by the first transition portion 21, lowering the risk of the conductor insulation layer being crushed and damaged, and preventing breakage of the first transition portion. The preferred size of the gap 305 is 0.2-0.3 mm.

[0033] The main plate 301 forms a support pad 304 for the conductor inside the notch 303, which corresponds to the transition position of the second transition portion 22. By supporting the conductor 20 with the pad 304, the second transition portion 22 of the conductor 20 can form a larger bending angle at the transition position, supporting the conductor 20 to bend gently and avoiding sharp bending of the conductor 20. This prevents the problem of reduced tensile strength and easy breakage of the conductor due to concentrated bending shear force.

[0034] like Figure 5 As shown, in this embodiment, the distance d1 between the upper edge of the notch 303 and the edge of the bottom plane of the lead groove 14 is greater than or equal to 0.5 mm. The distance d2 between the inner edge of the pad 304 and the width edge of the lead groove 14 is greater than or equal to 0.15 mm. The distance d1 is preferably 0.6-0.8 mm, and the distance d2 is preferably 0.2-0.3 mm. In this embodiment, the soldering part 40 uses solder paste material.

[0035] In summary, this invention utilizes a pair of terminal conductive plates spaced apart on the outer surface of the magnetic core end plate. Each terminal conductive plate has a pressure frame in the middle. The wire end extends through the lead groove on the end plate to below the pressure frame, and is then bent downwards and pressed and fixed to the outer side of the end plate by the pressure frame. This achieves the clamping and fixing of the wire end, effectively avoiding problems such as wire displacement and loosening during welding, significantly reducing the risk of wire detachment after welding, ensuring the structural integrity and stability of the component during long-term use, and extending the service life of the device. Secondly, the opening is filled with a welding part that covers the exposed part and is welded to the four edges of the pressure frame. The four edges of the pressure frame opening can restrict the welding part, inhibiting the solder from spreading outward along the terminal conductive plate before the solder solidifies. Furthermore, by setting a reasonable gap between the inner frame and the corresponding notch, and cooperating with the pad integrally connected to the main body plate, the shear force borne by the first transition part and the second transition part on the wire can be significantly reduced, which can effectively avoid damage to the wire insulation layer and reduce the risk of wire breakage under stress.

[0036] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A wire-wound surface-mount common-mode inductor, comprising: A magnetic core includes a core post and end plates connected to both ends of the core post; A terminal conductive plate has a main body plate attached to the surface of the end plate and a top plate integrally connected to the main body plate and attached to the top surface of the end plate. A conductor, comprising a conductive core and an insulating layer enclosing the core, the conductor being wound around the core post, and having an exposed portion of the core near its end. Welding section; The main body plate has a pressure frame with holes and a notch corresponding to the pressure frame. The pressure frame presses and fixes the end of the wire to the surface of the end plate inside the notch. The wire core at the exposed part is exposed by the holes. The inner and outer frames of the pressure frame on both sides of the holes press against the insulation layers on both sides of the exposed part. The welded portion at least partially covers the exposed portion and the pressure frame, so that the wire is electrically connected to the terminal conductive plate.

2. The wire-wound surface mount common mode inductor according to claim 1, characterized in that: The pressure frame is a rectangular frame, and the hole is a rectangular hole.

3. The wire-wound surface mount common mode inductor according to claim 1, characterized in that: The insulation layer of the conductor located on the main body side outside the exposed portion is pressed by the inner frame, and the gap between the inner edge of the inner frame and the inner edge of the notch is greater than or equal to 0.1 mm.

4. The wire-wound surface mount common mode inductor according to claim 3, characterized in that: The notch is located on the outside of the main body plate, and the main body plate has a pad for supporting the wire on the inside of the notch.

5. The wire-wound surface mount common mode inductor according to claim 4, characterized in that: The magnetic core also includes a cover plate that covers the bottom surface of the end plates connecting the two ends.

6. The wire-wound surface mount common mode inductor according to claim 5, characterized in that: The top surface of the end plate is provided with a lead groove to guide and support the wire through which it passes.

7. The wire-wound surface mount common mode inductor according to claim 6, characterized in that: The distance between the upper edge of the notch and the bottom plane edge of the lead groove is greater than or equal to 0.5 mm, and the distance between the inner edge of the pad and the width edge of the lead groove is greater than or equal to 0.15 mm.

8. The wire-wound surface mount common mode inductor according to claim 1, characterized in that, The welded portion completely covers the exposed portion.

9. The wire-wound surface mount common mode inductor according to claim 1, characterized in that, The soldering part uses solder paste.

10. The wire-wound surface-mount common-mode inductor according to claim 1, characterized in that, The conductor is made of copper enameled wire.

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