co-fired inductor
By using a spiral winding and spaced coil arrangement, combined with the wrapping design of the first and second magnetic cores, the problems of insufficient turns and short circuits in copper-iron co-fired inductors were solved, the inductance was increased, the insulation process was simplified, and high-temperature stability was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- NINGBO YULIU ELECTRONICS CO LTD
- Filing Date
- 2025-05-13
- Publication Date
- 2026-08-04
AI Technical Summary
Existing copper-iron co-fired inductor coils have a small number of turns, resulting in low inductance for the same volume. They are also prone to short circuits during high-temperature sintering, making multi-turn designs unsuitable.
The coil is wound in a spiral shape with intervals between adjacent turns. The coil is wrapped with a first magnetic core and a second magnetic core, eliminating the need for surface insulation of the coil. The structure is fixed by molding.
It increases the inductance for the same volume, increases the number of coil turns, avoids short circuits caused by high-temperature sintering, and simplifies the insulation process.
Smart Images
Figure CN224595347U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of electronic device technology, and more specifically, it relates to a co-fired inductor. Background Technology
[0002] Molded inductors, characterized by strong anti-saturation capability and excellent shielding performance, are increasingly widely used in power modules. With the growing application of artificial intelligence (AI), the power consumption of GPUs is many times higher than that of ordinary CPUs. This necessitates power modules with higher current requirements, requiring inductors to meet the demands of higher power density and extended operation at higher temperatures. To address this need, a copper-iron co-fired inductor design has been proposed. This type of inductor is fabricated by high-temperature sintering and solidifying soft magnetic alloy powder with copper electrodes under a reducing atmosphere.
[0003] Copper-iron co-fired inductors are a type of integrally molded inductor. They typically employ a through-hole electrode design with an equivalent number of 1 / 4 to 1 / 2 turns. They use spherical soft magnetic alloy powder, amorphous powder, or carbonyl powder as raw materials, which are mixed with resin and then integrally molded with the electrodes. The inductor is then sintered in an atmosphere furnace at 600-800℃. Because copper-iron co-fired inductors are generally processed at 600-800℃, the enameled wire on the copper wire surface cannot withstand temperatures exceeding 230℃. Therefore, insulating varnish cannot be used for insulation between the copper wires, failing to solve the insulation problem between the coils. Consequently, copper-iron co-fired inductors cannot use the multi-turn design of ordinary integrally molded inductors, as short circuits would occur during sintering. The coils of copper-iron co-fired inductors generally use... Figure 1 The winding method used in this design results in an actual number of turns between 1 / 4 and 1 / 2, which leads to a very low inductance for the same volume. This significantly reduces the flexibility in designing the inductance value. Utility Model Content
[0004] The purpose of this utility model embodiment is to provide a co-fired inductor to solve the technical problems of the existing technology, such as the small number of coil turns and the low inductance that can be obtained under the same volume.
[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a co-fired inductor is provided, comprising a first magnetic core, a second magnetic core, and a coil. The coil is spirally wound on the surface of the first magnetic core, and the number of turns of the coil is greater than one. Adjacent turns of the coil are spaced apart. The coil is located between the first magnetic core and the second magnetic core. The second magnetic core wraps around at least a portion of the surface of the first magnetic core and at least a portion of the coil faces away from the first magnetic core.
[0006] Optionally, the first magnetic core is a cuboid, and the axial direction of the coil is parallel to the length direction of the first magnetic core.
[0007] Optionally, the coil has a flat structure and has a first side and a second side disposed opposite to each other in the thickness direction, with the first side of the coil facing the first magnetic core and the second side of the coil facing the second magnetic core.
[0008] Optionally, the first magnetic core, the second magnetic core, and the coil are fixed by molding.
[0009] Optionally, the second magnetic core includes a base having a receiving cavity for accommodating the first magnetic core, which is disposed within the receiving cavity after the coil is wound around it.
[0010] Optionally, the receiving cavity has an opening, and the second magnetic core further includes a cover plate that covers the opening.
[0011] Optionally, both ends of the coil extend away from the first magnetic core, and both ends of the coil extend from between the cover plate and the base.
[0012] Optionally, the portion of the coil extending between the cover plate and the base is bent to the side of the cover plate opposite to the first magnetic core.
[0013] Optionally, the cover plate or the base is provided with a reserved slot for the coil to pass through on the side near the opening.
[0014] Optionally, both the first magnetic core and the second magnetic core are made by pressing copper-iron co-fired powder.
[0015] The beneficial effects of the co-fired inductor provided by this utility model are as follows: Compared with the prior art, the co-fired inductor of this utility model includes a first magnetic core, a second magnetic core and a coil. The coil is spirally wound on the surface of the first magnetic core, and the first magnetic core is located outside the second magnetic core. By spirally winding the coil, the number of turns after winding is at least one, thereby increasing the number of turns of the coil and thus increasing the inductance that can be obtained in the same volume. Furthermore, the adjacent turns are spaced apart, and this design does not require surface insulation treatment of the coil. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 This is a schematic diagram of the structure of a co-fired inductor in related technologies;
[0018] Figure 2 An exploded structural diagram of the first co-fired inductor provided for an embodiment of this utility model;
[0019] Figure 3 A three-dimensional structural diagram of the first magnetic core and the first type of coil provided for embodiments of this utility model;
[0020] Figure 4 An exploded view of the second type of co-fired inductor (coil not bent) provided in this embodiment of the present invention;
[0021] Figure 5 A three-dimensional structural diagram of the first magnetic core and the second type of coil provided for embodiments of this utility model;
[0022] Figure 6 A three-dimensional structural diagram of the second co-fired inductor provided in an embodiment of this utility model.
[0023] The following are the labeling elements in the figure:
[0024] 91 - Magnet; 92 - Copper wire;
[0025] 10-First magnetic core; 20-Second magnetic core; 21-Base; 210-Receiving cavity; 22-Cover plate; 30-Coil. Detailed Implementation
[0026] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.
[0027] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.
[0028] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.
[0030] Copper-iron co-fired inductors are a type of integrally molded inductor, typically employing a through-hole electrode design with an equivalent number of 1 / 4 to 1 / 2 turns. They use spherical soft magnetic alloy powder, amorphous powder, or carbonyl powder as raw materials, which are mixed with resin and then integrally molded with the electrodes. The inductor is then sintered in an atmosphere furnace at 600-800℃. Because copper-iron co-fired inductors are generally processed at 600-800℃, the enameled wire on the copper wire surface cannot withstand temperatures exceeding 230℃. Therefore, insulating varnish cannot be used for insulation between the copper wires, failing to address the insulation issue between the coils. Consequently, copper-iron co-fired inductors cannot use the multi-turn design of ordinary integrally molded inductors, as a short circuit would occur during sintering. The coils of copper-iron co-fired inductors generally use... Figure 1 In the winding method, the copper wire 92 extends and wraps around the magnet 91 along its length, with the actual number of turns being between 1 / 4 and 1 / 2 turns. The inductance that can be obtained for the same volume is very low, which greatly reduces the flexibility of the inductance design.
[0031] In another approach, a ceramic coating or a silica coating can be used instead of insulating varnish. These inorganic insulating materials can still provide insulation between coils 30 during high-temperature sintering. However, the preparation process for this coating is not very mature. Firstly, the surface has a porous microstructure, resulting in weaker insulation compared to insulating varnish. Secondly, current preparation processes for this type of insulating coating make it difficult to produce a thin and uniform coating; the coating is generally quite thick and uneven, affecting the uniformity of stress during molding and leading to peeling and damage of the insulation layer.
[0032] To alleviate or solve the above technical problems, this utility model proposes a co-fired inductor, including a first magnetic core 10, a second magnetic core 20 and a coil 30. By spirally winding the coil 30 around the outer periphery of the first magnetic core 10, the number of turns of the coil 30 can be increased, thereby increasing the inductance that can be obtained in the same volume. Furthermore, the coil 30 is spaced apart from adjacent turns, so this design does not require surface insulation treatment of the coil 30.
[0033] The co-fired inductor provided in the embodiments of this utility model will now be described.
[0034] Please refer to the following: Figures 2 to 6The co-fired inductor includes a first magnetic core 10, a second magnetic core 20, and a coil 30. The coil 30 is spirally wound on the surface of the first magnetic core 10, and the number of turns of the coil 30 is greater than one. Adjacent turns of the coil 30 are spaced apart. The coil 30 is located between the first magnetic core 10 and the second magnetic core 20. The second magnetic core 20 wraps around at least a portion of the surface of the first magnetic core 10 and at least a portion of the coil 30 on the side opposite to the first magnetic core 10.
[0035] The first magnetic core 10 is generally made of iron-based material, and the first magnetic core 10 is at least partially located inside the second magnetic core 20.
[0036] The coil 30 is made of conductive material and has a linear or elongated structure before winding. The coil 30 is spirally wound around the surface of the first magnetic core 10; that is, after being wound around the surface of the first magnetic core 10, the coil 30 is spiral-shaped. It should be noted that this spiral shape does not necessarily have to be a standard helix shape; it only needs to be wound from one end of the first magnetic core 10 to the other. Specifically, all parts of the coil 30 are set at an acute angle to the axis of the spiral; or, some parts of the coil 30 are perpendicular to the axis of the spiral, and some parts of the coil 30 are set at an acute angle to the axis of the spiral. Adjacent turns of the coil 30 are spaced apart. One complete turn of the coil 30 around the first magnetic core 10 can be called one turn of the coil 30. Since the coil 30 has more than one complete turn, the spaced-apart arrangement prevents short circuits between adjacent turns. The outer surface of the coil 30 does not need to be coated with insulating varnish or other insulating materials, and no short circuits will occur during high-temperature sintering.
[0037] The second magnetic core 20 is also made of iron-based material and is located outside the first magnetic core 10. After the coil 30 is wound around the surface of the first magnetic core 10, this entire assembly is placed inside the second magnetic core 20, so that the second magnetic core 20 is located outside the first magnetic core 10. The second magnetic core 20 covers at least a portion of the surface of the first magnetic core 10 and at least a portion of the coil 30 facing away from the first magnetic core 10. This can be understood as at least a portion of the surface of the first magnetic core 10 being shielded by the second magnetic core 20, and at least a portion of the surface of the coil 30 (facing away from the first magnetic core 10) being shielded by the second magnetic core 20. By placing the coil 30 between the first magnetic core 10 and the second magnetic core 20, a co-fired inductor is formed.
[0038] The co-fired inductor in the above embodiment includes a first magnetic core 10, a second magnetic core 20, and a coil 30. The coil 30 is spirally wound on the surface of the first magnetic core 10. The first magnetic core 10 is located outside the second magnetic core 20. By spirally winding the coil 30, the number of turns of the coil 30 after winding is at least one, thereby increasing the number of turns of the coil 30 and thus increasing the inductance that can be obtained in the same volume. Furthermore, the adjacent turns are spaced apart, so this design does not require surface insulation treatment of the coil 30.
[0039] Please refer to some embodiments of this utility model. Figure 2 and Figure 3 The co-fired inductor is a copper-iron co-fired inductor. The preparation steps of the copper-iron co-fired inductor are as follows:
[0040] S10: Preparation of copper-iron co-fired powder material: Mix one or two of atomized iron-silicon, iron-silicon-aluminum, iron-silicon-chromium, amorphous or carbonyl iron with 3-15wt% silicone resin, 1-2wt% epoxy resin, 8wt% acetone or anhydrous ethanol, and then granulate by reciprocating granulation. After baking at 50-60℃ for 2 hours, take the powder (copper-iron co-fired powder) with a mesh size of 80-200 for later use.
[0041] S20: Assembly and Forming: The first magnetic core 10 is cold-pressed for 15 seconds at 200-300 MPa using a cold pressing process. Then, the coil 30 is wound according to a predetermined method. Next, the second magnetic core 20 is cold-pressed for 3 seconds at 20-60 MPa using a lower pressure in a secondary forming mold. The second magnetic core 20 remains in the mold. Then, the first magnetic core 10 with the coil 30 wound is placed into the secondary-formed second magnetic core 20. At this time, the mold for the second magnetic core 20 is heated to 180-200℃ while undergoing a second pressing and holding pressure for 60-90 seconds. The blank is then demolded. The raw materials for both the first magnetic core 10 and the second magnetic core 20 are the aforementioned copper-iron co-fired powder material.
[0042] S30: Sintering: Place the shaped product into an atmosphere furnace under hydrogen or nitrogen protection, heat to 680℃ for 2 hours and hold for 40 minutes, then cool naturally to below 150℃ to complete the preparation.
[0043] Please refer to some embodiments of this utility model. Figure 3 The first magnetic core 10 is a cuboid, and the axis in which the coil 30 is wound is parallel to the length direction of the first magnetic core 10. When the first magnetic core 10 is a cuboid, it has a length direction, a width direction, and a height direction, with its length direction being the direction in which the first magnetic core 10 has the largest dimension. The axis in which the coil 30 is wound is the same as the axis in which the coil 30 is wound into a spiral shape.
[0044] By setting the axis of the coil 30 to be parallel to the length direction of the first magnetic core 10, the space of the first magnetic core 10 in the length direction can be fully utilized, the number of turns of the coil 30 after winding can be increased, and thus the inductance under the same volume can be increased.
[0045] In other embodiments, the first magnetic core 10 may also be in the shape of a cube, a triangular pyramid, etc., and its specific shape is not limited here.
[0046] Please refer to some embodiments of this utility model. Figure 2 and Figure 3 The coil 30 has a flat structure and has a first side and a second side arranged opposite to each other in the thickness direction. The first side of the coil 30 faces the first magnetic core 10, and the second side of the coil 30 faces the second magnetic core 20. The coil 30 has a flat structure and a rectangular cross-sectional shape. The direction in which the size of the coil 30 is smallest is the thickness direction of the coil 30. The first side and the second side of the coil 30 are the two surfaces with larger areas. The first side of the coil 30 is in contact with the surface of the first magnetic core 10, and the second side of the coil 30 is in contact with the surface of the second magnetic core 20.
[0047] By setting the coil 30 to a flat structure, the contact area between the coil 30 and the first magnetic core 10 and the second magnetic core 20 can be increased, thereby improving the inductance of the co-fired inductor. Moreover, compared to a structure with a circular cross-section, the coil 30 is less likely to roll on the first magnetic core 10, and adjacent turns of the coil 30 will not come into contact with each other, reducing the possibility of short circuits in the coil 30.
[0048] In some embodiments of this invention, the first magnetic core 10, the second magnetic core 20, and the coil 30 are fixed by molding. After the first magnetic core 10, on which the coil 30 is wound, is placed on the second magnetic core 20, it is pressed and held at a predetermined temperature for a predetermined time, which fixes the first magnetic core 10, the second magnetic core 20, and the coil 30 to each other.
[0049] The first magnetic core 10, the second magnetic core 20, and the coil 30 are fixed by molding, which is convenient and quick. The first magnetic core 10 and the second magnetic core 20 are embedded on both sides of the coil 30 respectively, without the need to introduce other installation structures.
[0050] Please refer to some embodiments of this utility model. Figure 2 and Figure 4 The second magnetic core 20 includes a base 21 having a receiving cavity 210 for accommodating the first magnetic core 10, which is disposed within the receiving cavity 210 after the coil 30 is wound around it. The first magnetic core 10 is placed inside the base 21 after the coil 30 is wound around it, thereby covering the outside of the first magnetic core 10 with the base 21.
[0051] By providing a base 21 with a receiving cavity 210, the first magnetic core 10 with the coil 30 wound around it can be located inside the second magnetic core 20.
[0052] In some embodiments, the base 21 has a cuboid shape on its outer perimeter, and the interior of the base 21 has a receiving cavity 210, which is also cuboid in shape and is adapted to the shape of the first magnetic core 10. When the outer perimeter of the base 21 is cuboid, it is easier to mold, the structure is simpler, and the manufacturing cost is lower.
[0053] Please refer to some embodiments of this utility model. Figure 4 The receiving cavity 210 has an opening, and the second magnetic core 20 also includes a cover plate 22, which is placed over the opening. The receiving cavity 210 has an opening, and after the first magnetic core 10 is wound with the coil 30, it can be inserted into the interior of the base 21 through the opening. The cover plate 22 being placed over the opening means that the cover plate 22 is positioned close to the opening; the cover plate 22 does not necessarily completely block the opening, but can partially block it.
[0054] By setting the cover plate 22, firstly, the contact surface between the second magnetic core 20 and the coil 30 can be increased, thereby improving the inductance; secondly, the structure of the co-fired inductor can be made more complete, and the coil 30 is not exposed.
[0055] In some embodiments, the side of the cover plate 22 facing the base 21 is abutted against the top wall of the base 21. In this way, the cover plate 22 and the base 21 can be fixed together by molding, and the contact between the coil 30 and the cover plate 22 is also tighter.
[0056] Please refer to some embodiments of this utility model. Figure 5 Both ends of the coil 30 extend away from the first magnetic core 10, and both ends of the coil 30 extend out between the cover plate 22 and the base 21. The coil 30 includes two ends and a middle portion in its length direction, with the middle portion of the coil 30 wound around the outer periphery of the first magnetic core 10, and the two ends of the coil 30 extending away from the first magnetic core 10 and disposed outside the second magnetic core 20.
[0057] By extending both ends of the coil 30 away from the first magnetic core 10, the extended coil 30 can be bent to other positions, increasing the equivalent number of turns of the coil 30 and improving the inductance.
[0058] Please refer to some embodiments of this utility model. Figure 6The portion of coil 30 extending between cover plate 22 and base 21 is bent to the side of cover plate 22 facing away from the first magnetic core 10. Cover plate 22 has a first side and a second side, with the first side of cover plate 22 facing the first magnetic core 10 and the second side of cover plate 22 facing away from the first magnetic core 10. The portion of coil 30 extending between cover plate 22 and base 21 can be referred to as an extension section, which is bent to the side of cover plate 22 facing away from the first magnetic core 10 (the second side of cover plate 22), so that the extension section and the second side of cover plate 22 are in close contact with each other.
[0059] By extending both ends of the coil 30 away from the first magnetic core 10, the extended coil 30 can be bent to the second side of the cover plate 22, thereby increasing the equivalent number of turns of the coil 30 and improving the inductance.
[0060] In other embodiments, the portion of coil 30 extending between cover plate 22 and base 21 is bent to the outer surface of second magnetic core 20.
[0061] Please refer to some embodiments of this utility model. Figure 6 The cover plate 22 or the base 21 has a reserved slot near the opening for the coil 30 to pass through. The reserved slot is designed so that the extension of the coil 30 will not affect the connection between the cover plate 22 and the base 21. Both ends of the coil 30 extend out of the base 21, and correspondingly, there are two reserved slots, one for each end of the coil 30 to pass through.
[0062] By setting the reserved slot, the coil 30 can extend out of the base 21 from the reserved slot without pushing up the cover plate 22, and the cover plate 22 can still be tightly fixed on the base 21.
[0063] Please see Figure 4 and Figure 6 The co-fired inductor is a copper-iron co-fired inductor. The preparation steps of the copper-iron co-fired inductor are as follows:
[0064] S10: Preparation of copper-iron co-fired powder material: Mix one or two of atomized iron-silicon, iron-silicon-aluminum, iron-silicon-chromium, amorphous or carbonyl iron with 3-15wt% silicone resin, 1-2wt% epoxy resin, 8wt% acetone or anhydrous ethanol, and then granulate by reciprocating granulation. After baking at 50-60℃ for 2 hours, take the powder (copper-iron co-fired powder) with a mesh size of 80-200 for later use.
[0065] S20: Assembly and Molding: The first magnetic core 10 is pressed out in 15 seconds at 200-300MPa using a cold pressing process. Then, the coil 30 is wound according to a predetermined method. Next, the second magnetic core 20 is cold-pressed out in a secondary molding die at 20-60MPa for 3 seconds using a lower pressure. The second magnetic core 20 remains in the die. The first magnetic core 10 with the coil 30 wound is then placed into the secondary-molded second magnetic core 20. A cover plate 22 of the same size is placed on the mold cavity of the second magnetic core 20 to press down the protruding coil 30. The cover plate 22 has a pre-reserved groove at the copper wire lead-out end. The mold of the second magnetic core 20 is heated to 180-200℃, and powder is poured in again. A second pressing is performed, holding the pressure for 60-90 seconds. Then, the cover plate 22 is removed, and the die is demolded to obtain the blank. After demolding, the protruding coil 30 is bent from both sides towards the middle to obtain the product blank as shown. Figure 6 The raw materials for the first magnetic core 10 and the second magnetic core 20 are both the aforementioned copper-iron co-fired powder materials.
[0066] S30: Sintering: Place the shaped product into an atmosphere furnace under hydrogen or nitrogen protection, heat to 680℃ for 2 hours and hold for 40 minutes, then cool naturally to below 150℃ to complete the preparation.
[0067] To further illustrate the advantages of this utility model, Figure 2 and Figure 3 The embodiments and Figure 1 The comparison of the schemes (Comparative Example 1 and Comparative Example 2) is shown in Table 1. It can be seen that the inductor volume and size are the same in each embodiment. However, the first co-fired inductor provided by this utility model ( Figure 2 and Figure 3 In the corresponding embodiments (referred to as Embodiment 1 and Embodiment 2 in the table), the coil 30 is wound with 1.5 turns, and its inductance is significantly improved.
[0068] Table 1
[0069]
[0070] Will Figures 4 to 6 The embodiments and Figure 1 The comparison of the schemes (Comparative Example 1 and Comparative Example 2) is shown in Table 1. It can be seen that the inductor volume and size are the same in all embodiments. However, the second co-fired inductor provided by this utility model ( Figures 4 to 6 In the corresponding embodiments (referred to as Embodiment 3 and Embodiment 4 in the table), the coil 30 is wound with 2.25 turns, and its inductance is significantly improved.
[0071] Table 2
[0072]
[0073]
[0074] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A co-fired inductor, characterized in that: The device includes a first magnetic core, a second magnetic core, and a coil. The coil is spirally wound on the surface of the first magnetic core, and the number of turns of the coil is greater than one. Adjacent turns of the coil are spaced apart. The coil is located between the first magnetic core and the second magnetic core. The second magnetic core covers at least a portion of the surface of the first magnetic core and at least a portion of the coil faces away from the first magnetic core.
2. The co-fired inductor as described in claim 1, characterized in that: The first magnetic core is a cuboid, and the axis in which the coil is wound is parallel to the length direction of the first magnetic core.
3. The co-fired inductor as described in claim 1, characterized in that: The coil has a flat structure and has a first side and a second side that are arranged opposite to each other in the thickness direction. The first side of the coil faces the first magnetic core, and the second side of the coil faces the second magnetic core.
4. The co-fired inductor as described in claim 1, characterized in that: The first magnetic core, the second magnetic core, and the coil are fixed by molding.
5. The co-fired inductor as described in any one of claims 1-4, characterized in that: The second magnetic core includes a base having a receiving cavity for accommodating the first magnetic core, which is disposed within the receiving cavity after the coil is wound around it.
6. The co-fired inductor as described in claim 5, characterized in that: The receiving cavity has an opening, and the second magnetic core further includes a cover plate that covers the opening.
7. The co-fired inductor as described in claim 6, characterized in that: Both ends of the coil extend away from the first magnetic core, and both ends of the coil extend out between the cover plate and the base.
8. The co-fired inductor as described in claim 7, characterized in that: The portion of the coil extending between the cover plate and the base is bent to the side of the cover plate facing away from the first magnetic core.
9. The co-fired inductor as described in claim 7, characterized in that: The cover plate or the base has a reserved slot on the side near the opening for the coil to pass through.
10. The co-fired inductor as described in any one of claims 1-4, characterized in that: Both the first magnetic core and the second magnetic core are made of copper-iron co-fired powder.