Manufacturing method of coupling inductor formed by assembling E-shaped magnetic core and magnetic ring

Abstract

The invention relates to a manufacturing method of a coupling inductor formed by assembling an E-shaped magnetic core and a magnetic ring. The problems that an existing coupling inductor is large in size and low in reliability are solved. The inductor manufactured through the manufacturing method of the coupling inductor formed by assembling the E-shaped magnetic core and the magnetic ring comprises the E-shaped magnetic core, the magnetic ring, a magnetic circuit closed magnetic core, a first coil, a second coil and soft magnetic metal powder, a middle column is arranged in the middle of the E-shaped magnetic core, vertical walls are arranged on the periphery of the E-shaped magnetic core, a round hole is formed in the middle of a bottom plate of the magnetic ring, and the round hole and the middle column are arranged in a matched mode. And a closing plate is arranged on the magnetic circuit closing magnetic core. Two inductance units are highly integrated in a three-dimensional space through nesting and assembling of the E-shaped magnetic core, the magnetic ring and the magnetic circuit closed magnetic core, a closed magnetic circuit is formed through hot press molding, the overall size is reduced, and the power density is improved; in addition, the distance and the position of the coil are effectively guaranteed, the E-shaped magnetic core and the magnetic ring are preheated and formed firstly, it can be guaranteed that the coil deformation is smaller during hot press forming, and therefore the reliability of the coupling inductor is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of inductor technology, and more specifically to a method for manufacturing a coupled inductor formed by assembling an E-type magnetic core and a magnetic ring. Background Technology

[0002] Coupled inductors, as key components in electronic circuits, function primarily to transfer energy and couple signals through magnetic coupling, and are widely used in various power electronic systems. Traditional coupled inductors often employ a single magnetic core structure (such as double E-type core docking, nested magnetic rings, etc.), which presents the following technical drawbacks in practical applications: Poor magnetic circuit stability: Single magnetic core structure is prone to magnetic reluctance fluctuations due to problems such as assembly gaps and insufficient uniformity of magnetic core materials, which in turn affects the inductance accuracy and coupling efficiency. Especially under high frequency conditions, magnetic circuit loss increases significantly. Low structural integration: The coil winding, magnetic core assembly, and electrode lead-out processes of traditional coupled inductors are relatively independent. During the assembly process, problems such as coil displacement and loose magnetic core bonding are prone to occur, which not only reduces production efficiency but also leads to poor product consistency. Limited adaptability: Traditional coupled inductors require redesigning the core size and coil parameters to meet the application requirements of different power and frequency, making it difficult to adapt to multiple scenarios through flexible structural adjustments, which increases R&D and production costs. To address the aforementioned issues, there is an urgent need in this field for a coupled inductor structure that combines a stable magnetic circuit, high integration, and strong adaptability, along with an efficient and controllable manufacturing method, to meet the demands of electronic devices for miniaturization, high precision, and high reliability. Summary of the Invention

[0003] The purpose of this invention is to solve the problems of large size and low reliability of existing coupled inductors.

[0004] The technical solution adopted to solve the technical problem proposed by the present invention is as follows: a method for manufacturing a coupled inductor assembled from an E-type magnetic core and a magnetic ring, the manufacturing method comprising the following steps: Step A: Pre-press and form E-type magnetic core, magnetic ring, and magnetic circuit closed magnetic core. The E-type magnetic core is a magnetic core with a central column in the middle and vertical walls around it, and the cross-section is E-shaped. The magnetic ring is a magnetic ring with a circular hole in the middle of the base plate. The circular hole is set to cooperate with the central column. The magnetic circuit closed magnetic core is provided with a closed plate that cooperates with the top of the vertical wall of the E-type magnetic core. The closed plate is provided with electrode pin openings. Step B: After inserting a coil into the outer periphery of the central column of the E-type magnetic core to form the first coil, lead the two ends of the first coil out to the vertical wall of the E-type magnetic core and then bend them to form the first pin and the second pin. Step C: Place the magnetic ring onto the central post of the E-type magnetic core; Step D: After inserting a coil into the outer periphery of the central column of the E-type magnetic core above the magnetic ring to form a second coil, lead the two ends of the second coil out to the vertical wall of the E-type magnetic core and then bend them to form a third and fourth pin. Step E: Fill the vertical wall of the E-type magnetic core with soft magnetic metal powder. Place the closing plate of the magnetic circuit closed core on the soft magnetic metal powder and the vertical wall. The first pin, second pin, third pin and fourth pin are respectively set to correspond to an electrode pin port. Then, the magnetic circuit closed core and soft magnetic metal powder are hot-pressed to form a closed magnetic circuit. Step F: After stripping the paint from the first, second, third, and fourth pins, immerse them in tin or electroplate them to form the first, second, third, and fourth electrodes, respectively.

[0005] The technical solutions that further define the present invention include: In step E, the soft magnetic metal powder is one or more of carbonyl iron powder, iron-silicon-chromium powder, iron-silicon-aluminum powder, and iron-nickel magnetic powder.

[0006] In step A, the preform is degreased after pre-pressing to remove the molding agent.

[0007] In step E, the hot pressing temperature is controlled at 150-300℃, the hot pressing pressure is controlled at 50-150MPa, and the hot pressing time is controlled at 10-30min.

[0008] In step A, the upright wall of the E-type magnetic core is a cube structure, and the base plate of the magnetic ring is a cube structure.

[0009] In step F, the third electrode and the fourth electrode are respectively positioned opposite to the first electrode and the second electrode.

[0010] The beneficial effects of the present invention through the above technical solution are as follows: The coupled inductor manufactured by the method of assembling the E-type magnetic core and magnetic ring of the present invention integrates two inductor units into a three-dimensional space by nesting the E-type magnetic core, magnetic ring and magnetic circuit closed core. The closed magnetic circuit is formed by hot pressing, which significantly reduces the overall volume and improves the power density. In addition, it can effectively ensure the coil spacing and position. Preheating the E-type magnetic core and magnetic ring first can ensure that the coil deformation is smaller during hot pressing, thereby ensuring the reliability of the coupled inductor. Attached Figure Description

[0011] Figure 1 This is a three-dimensional structural diagram of a coupled inductor assembled from an E-type magnetic core and a magnetic ring according to the present invention.

[0012] Figure 2 This is an exploded structural diagram of a coupled inductor assembled from an E-type magnetic core and a magnetic ring according to the present invention.

[0013] Figure 3 This is a schematic diagram of the assembly structure of the magnetic ring and the second coil of a coupled inductor formed by assembling an E-type magnetic core and a magnetic ring according to the present invention.

[0014] Figure 4 This is a schematic diagram of the assembly structure of the E-type magnetic core and the first coil of a coupled inductor formed by assembling an E-type magnetic core and a magnetic ring according to the present invention.

[0015] Among them, there is an E-type magnetic core 1, a central column 11, a vertical wall 12, a magnetic ring 2, a circular hole 21, a magnetic circuit closed magnetic core 3, a closed plate 31, an electrode pin port 32, a first coil 4, a first pin / first electrode 41, a second pin / second electrode 42, a second coil 5, a third pin / third electrode 51, and a fourth pin / fourth electrode 52. Detailed Implementation

[0016] The structure of the present invention will be further described below with reference to the accompanying drawings.

[0017] Reference Figures 1 to 4The coupled inductor manufactured by the method of assembling an E-type magnetic core and a magnetic ring according to the present invention includes an E-type magnetic core 1, a magnetic ring 2, a magnetic core 3 with a closed magnetic circuit, a first coil 4, a second coil 5, and soft magnetic metal powder. The E-type magnetic core 1 is a magnetic core with a central column 11 and surrounding vertical walls 12, and has an E-shaped cross-section. In this embodiment, the vertical walls 12 of the E-type magnetic core 1 are cubic structures, and the base plate of the magnetic ring 2 is also a cubic structure, which facilitates manufacturing. In specific implementations, the shapes of the vertical walls 12 and the base plate of the magnetic ring 2 can be set as needed. The magnetic ring 2 is a magnetic ring with a circular hole 21 in the middle of the base plate. The circular hole 21 is set to cooperate with the central column 11. The magnetic circuit closed core 3 is provided with a closed plate 31 that cooperates with the top of the wall 12 of the E-type magnetic core 1. The closed plate 31 is provided with an electrode pin opening 32. The first coil 4 is sleeved on the central column 11 of the E-type magnetic core 1. The magnetic ring 2 and the second coil 5 are both sleeved on the central column 11. The magnetic ring 2 is located on the first coil 4, and the second coil 5 is located on the magnetic ring 2. The closed plate 31 is located on the wall 12 to form a magnetic circuit closed space. Soft magnetic metal powder is filled in the magnetic circuit closed space. The closed plate 31 and the soft magnetic metal powder are hot-pressed to form a closed magnetic circuit. The first electrode 41 and the second electrode 42 led out from the first coil 4 are provided on one side wall of the wall 12. The third electrode 51 and the fourth electrode 52 led out from the second coil 5 are provided on the other side of the wall 12. The first electrode 41, the second electrode 42, the third electrode 51 and the fourth electrode 52 are respectively set with an electrode pin opening 32. In this embodiment, the third electrode 51 and the fourth electrode 52 are respectively positioned opposite to the first electrode 41 and the second electrode 42. This facilitates layout and use. The coupled inductor assembled from the E-type magnetic core 1 and the magnetic ring 2 of the present invention integrates two inductor units into a three-dimensional space through the nested assembly of the E-type magnetic core 1, the magnetic ring 2, and the magnetic circuit closed core 3. The closed magnetic circuit is formed by hot pressing, which significantly reduces the overall volume and improves the power density. In addition, it can effectively ensure the coil spacing and position. Preheating the E-type magnetic core 1 and the magnetic ring 2 before hot pressing ensures that the coil deformation is smaller, thereby ensuring the reliability of the coupled inductor.

[0018] A method for manufacturing a coupled inductor assembled from an E-type magnetic core 1 and a magnetic ring 2 according to the present invention, the method comprising the following steps: Step A: Pre-press and form E-type magnetic core 1, magnetic ring 2, and magnetic circuit closed magnetic core 3; after pre-pressing, degrease the blank: degreasing temperature 300-500℃, degreasing time 1-3h, to remove the molding agent and avoid the generation of bubbles or cracks in subsequent processes.

[0019] Step B: After inserting a coil into the outer periphery of the central column 11 of the E-type magnetic core 1, a first coil 4 is formed. The two ends of the first coil 4 are led out to the wall of the vertical wall 12 of the E-type magnetic core 1 and then bent to form a first pin and a second pin. The length of the first pin and the second pin is preferably 5-15mm, which facilitates subsequent electrode processing and circuit soldering.

[0020] Step C: Place the magnetic ring 2 onto the central post 11 of the E-type magnetic core 1; thereby stabilizing the positioning of the magnetic ring 2 and the E-type magnetic core 1.

[0021] Step D: After inserting a coil into the outer periphery of the central column 11 of the E-type magnetic core above the magnetic ring 2, a second coil 5 is formed. The two ends of the second coil 5 are led out to the wall 12 of the E-type magnetic core 1 and then bent to form a third pin and a fourth pin. The length of the third pin and the fourth pin is preferably 5-15mm, which facilitates subsequent electrode processing and circuit soldering.

[0022] Step E: Soft magnetic metal powder is filled into the vertical wall 12 of the E-type magnetic core 1. The closing plate 31 of the magnetic circuit closed core 3 is placed on the soft magnetic metal powder and the vertical wall 12. The first pin 41, the second pin 42, the third pin 51, and the fourth pin 52 are respectively set with an electrode pin port 32. Then, the magnetic circuit closed core 3 and the soft magnetic metal powder are hot-pressed to form a closed magnetic circuit. Through the hot-pressing process, under certain temperature and pressure, the soft magnetic metal powder and the magnetic core structure are firmly bonded to form a robust whole with strong resistance to mechanical vibration and impact, improving the long-term reliability of the product. In this embodiment, the soft magnetic metal powder is iron-silicon-aluminum powder. To pursue higher permeability and lower loss, the soft magnetic metal powder can also be iron-silicon-chromium powder or iron-nickel-molybdenum powder. Iron-silicon-aluminum powder, iron-silicon-chromium powder, or iron-nickel magnetic powder have high resistivity and can effectively suppress high-frequency eddy current loss. Meanwhile, this structure places the coil inside the magnetic core, reducing electromagnetic radiation and interference at high frequencies. In specific implementations, the soft magnetic metal powder can also be carbonyl iron powder, or more than one of carbonyl iron powder, iron-silicon-chromium powder, iron-silicon-aluminum powder, and iron-nickel magnetic powder. By filling the magnetic circuit with soft magnetic metal powders of different properties, this invention can easily change the magnetic reluctance of that part of the magnetic circuit, thereby achieving precise "programming" of the entire coupled inductor's electrical parameters (such as coupling coefficient K and leakage inductance Lk), greatly facilitating circuit design and optimization.

[0023] Step F: After stripping the paint from the first pin 41, the second pin 42, the third pin 51, and the fourth pin 52, tin-plating or electroplating are performed to form the first electrode 41, the second electrode 42, the third electrode 51, and the fourth electrode 52. Finally, the electrodes are trimmed, and the pin length is adjusted to the designed size, preferably 3-10mm. All electrode pins are led out from the side wall of the upright and pass through the electrode pin openings on the closed plate, with a neat layout, which facilitates automated mounting and soldering on the PCB board.

[0024] This invention introduces a controllable "distributed air gap" into the magnetic circuit by filling the closed space of the magnetic circuit with soft magnetic metal powder. By selecting soft magnetic metal powders with different permeabilities, compositions (such as iron-silicon-aluminum powder, iron-nickel powder, etc.) and filling densities, the magnetic coupling strength and leakage inductance between the primary and secondary windings can be precisely adjusted to meet the requirements of different circuit topologies (such as LLC resonant converters) for resonant inductance.

[0025] Although specific embodiments of the present invention have been described in detail with reference to the accompanying drawings, this should not be construed as limiting the scope of protection of the present invention. Various modifications and variations that can be made by those skilled in the art without inventive effort within the scope described in the claims still fall within the scope of protection of the present invention.

Claims

1. A method for manufacturing a coupled inductor assembled from an E-type magnetic core and a magnetic ring, characterized in that: The manufacturing method includes the following steps: Step A: Pre-press and form E-type magnetic core, magnetic ring, and magnetic circuit closed magnetic core. The E-type magnetic core is a magnetic core with a central column in the middle and vertical walls around it, and the cross-section is E-shaped. The magnetic ring is a magnetic ring with a circular hole in the middle of the base plate. The circular hole is set to cooperate with the central column. The magnetic circuit closed magnetic core is provided with a closed plate that cooperates with the top of the vertical wall of the E-type magnetic core. The closed plate is provided with electrode pin openings. Step B: After inserting a coil into the outer periphery of the central column of the E-type magnetic core to form the first coil, lead the two ends of the first coil out to the vertical wall of the E-type magnetic core and then bend them to form the first pin and the second pin. Step C: Place the magnetic ring onto the central post of the E-type magnetic core; Step D: After inserting a coil into the outer periphery of the central column of the E-type magnetic core above the magnetic ring to form a second coil, lead the two ends of the second coil out to the vertical wall of the E-type magnetic core and then bend them to form a third and fourth pin. Step E: Fill the vertical wall of the E-type magnetic core with soft magnetic metal powder. Place the closing plate of the magnetic circuit closed core on the soft magnetic metal powder and the vertical wall. The first pin, second pin, third pin and fourth pin are respectively set to correspond to an electrode pin port. Then, the magnetic circuit closed core and soft magnetic metal powder are hot-pressed to form a closed magnetic circuit. Step F: After stripping the paint from the first, second, third, and fourth pins, immerse them in tin or electroplate them to form the first, second, third, and fourth electrodes, respectively.

2. The manufacturing method of a coupled inductor assembled from an E-type magnetic core and a magnetic ring as described in claim 1, characterized in that: In step E, the soft magnetic metal powder is one or more of carbonyl iron powder, iron-silicon-chromium powder, iron-silicon-aluminum powder, and iron-nickel magnetic powder.

3. The manufacturing method of a coupled inductor assembled from an E-type magnetic core and a magnetic ring as described in claim 1, characterized in that: In step A, the preform is degreased after pre-pressing to remove the molding agent.

4. The manufacturing method of a coupled inductor assembled from an E-type magnetic core and a magnetic ring as described in claim 1, characterized in that: In step E, the hot pressing temperature is controlled at 150-300℃, the hot pressing pressure is controlled at 50-150MPa, and the hot pressing time is controlled at 10-30min.

5. The manufacturing method of a coupled inductor assembled from an E-type magnetic core and a magnetic ring as described in claim 1, characterized in that: In step A, the upright wall of the E-type magnetic core is a cube structure, and the base plate of the magnetic ring is a cube structure.

6. The manufacturing method of a coupled inductor assembled from an E-type magnetic core and a magnetic ring as described in claim 1, characterized in that: In step F, the third electrode and the fourth electrode are respectively positioned opposite to the first electrode and the second electrode.

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