Co-fired inductor and processing method thereof
By adopting a co-fired inductor design in the inductor and using the combination of metal sheet windings and cold pressed cores, the inductor is easily broken and magnetic leakage after bending, and a higher inductance value and a more compact structure are achieved, meeting the lightweight and lightweight needs of electronic products.
Patent Information
- Application Number
- CN202311615112.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-29
- Publication Date
- 2025-05-30
AI Technical Summary
The existing inductors are prone to break after being bent, the electrode pins are poor in planarity, low inductance value, easy to leak magnetically, and the product size is large, which cannot meet the lightweight and thinning needs of electronic products.
A co-fired inductor design is adopted, in which the winding is made of metal sheets, and is completely embedded in the groove of the cold-pressed core through the connection part, and a magnet shell is formed on the outside of the winding and the cold-pressed core, reducing magnetic leakage and improving product induction value.
By reducing magnetic leakage and increasing product induction value, a higher working current and a more compact overall structure are achieved, meeting the lightweight and thinning needs of electronic products.
Smart Images
Figure CN120072476A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of electronic magnetic components, and in particular to a co-fired inductor and a processing method thereof. Background Art
[0002] In order to make electronic products as light and thin as possible while being highly functionally integrated, electronic components are gradually moving towards small size and high power. This development trend has promoted the development of power supply technology and inductor technology, with the goal of improving the space utilization of inductor products.
[0003] There is an inductor made by an integrated co-firing method. The U-shaped copper sheet includes two electrodes. Each electrode is bent twice to form a U shape, and then co-fired to improve the magnetic permeability and save space. The defects are: the electrode pins are easy to break after bending, the flatness of the electrode surface is poor, the inductance value is low, and it is easy to leak magnetic flux.
[0004] There is another type of dual-phase coupled inductor, where the electrode pins are U-shaped relative to the conductor sheet, and then the sheet-shaped magnetic core is embedded in the U-shaped electrode pins to support the electrode pins; there is also an inductor, where a groove is opened on the package body, the core part of the conductor is embedded in the groove, and the conductor pins are bent and attached to the side of the package body. The defects of the above two structures include: at least part of the structure on the conductor is located outside the magnet, the leakage magnetic amount is large, and the product size is large. Summary of the invention
[0005] The purpose of the present invention is to provide a co-fired inductor and a processing method thereof, which has less magnetic leakage and high product inductance value.
[0006] To achieve this object, on the one hand, the present invention adopts the following technical solutions:
[0007] A co-fired inductor comprises: a winding, comprising a U-shaped main body, wherein two ends of the main body are respectively connected to a limiting part through a connecting part, and the connected main body, the connecting part and the limiting part form a receiving part with a U-shaped cross section; a cold-pressed core, comprising a block-shaped pressed body and a groove provided on the pressed body, wherein the pressed body is located in the receiving part, the main body and the limiting part are respectively located on opposite sides of the pressed body, and the connecting part is completely embedded in the groove; and a magnet housing, at least partially wrapped around the outer side of the winding and the cold-pressed core.
[0008] In one of the preferred embodiments, the winding is made of a metal sheet, and the thickness of the metal sheet is smaller than the depth of the groove.
[0009] In one of the preferred embodiments, in a direction perpendicular to the plane where the winding is located, the cross-section of the winding is rectangular.
[0010] In one preferred embodiment, the winding is made of copper, silver or copper-silver alloy.
[0011] In one preferred embodiment, the outer surface of the winding is directly in contact with the outer surface of the cold-pressed core and the inner surface of the magnet housing.
[0012] In one preferred embodiment, the co-fired inductor comprises one or more windings, and all of the windings are symmetrically connected to the cold pressed core.
[0013] On the other hand, the present invention adopts the following technical solutions:
[0014] The processing method of the co-fired inductor comprises the following steps:
[0015] Step S1: bending the metal sheet into a U shape, bending the metal sheet once in a direction perpendicular to the plane where the metal sheet is located to form a main body and a connecting part of the winding, bending the connecting part twice in a direction parallel to the plane where the main body is located to form a limiting part, and forming a U-shaped accommodating part between the main body, the connecting part and the limiting part;
[0016] Step S2: preparing a block-shaped pressed body, and simultaneously pressing to form a groove on the pressed body to obtain a cold pressed core;
[0017] Step S3: inserting the pressed body into the receiving portion, and the connecting portion is completely embedded in the groove;
[0018] Step S4: forming a magnet housing after powder filling, and obtaining the co-fired inductor after sintering.
[0019] In one preferred embodiment, after step S4, step S5 is further included: impregnation, spraying, bending and electroplating after sintering.
[0020] In one preferred embodiment, the method for preparing the cold pressed core in step S2 is: applying 1.3t / cm 2 The cold pressed core is formed into a shape by a pressure of 150° C. to 250° C. and the time is 5 to 15 minutes.
[0021] In one of the preferred embodiments, the method for forming the magnet shell after filling with powder in step S4 is: placing the winding and the cold-pressed core into a mold, filling powder to a set amount, applying a pressure of 16 t / cm2 to the winding, the cold-pressed core and the filling powder by a cold pressing process, and annealing after cold pressing, the annealing temperature is 580°C-700°C, and the annealing time is 30 minutes-120 minutes.
[0022] The connecting part of the co-fired inductor disclosed by the present invention is completely embedded in the groove, forming a magnet housing on the outside of the winding and the cold pressing core. There is no exposed part on the winding, reducing magnetic leakage, having a high working current, and improving the inductance value of the product. The connecting part does not protrude from the cold pressing core, making the overall structure of the co-fired inductor more compact, fully utilizing the material space, reducing the product size, and being beneficial to the thinness and lightness of electronic products. The cold pressing core can support the main body part and the limiting part, reducing the risk of bending and breaking the pins. The product has high electrode size accuracy and more uniform product density, meeting the requirements of miniaturization of electronic products.
[0023] The processing method of the co-fired inductor provided by the present invention is double pressing and forming. Compared with the product formed at one time, the inductance value is significantly improved, the forming density is higher and more uniform, the electrode size tolerance is smaller, the pressing density is higher, and it has good formability. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figures 1 to 3 They are respectively schematic diagrams of three processing stages of the winding provided by the specific embodiment of the present invention;
[0025] Figure 4 It is a schematic structural diagram of the cold pressing core provided by the specific embodiment of the present invention;
[0026] Figure 5 It is a schematic combined structural diagram of the winding and the cold pressing core provided by the specific embodiment of the present invention;
[0027] Figure 6 It is a schematic structural diagram of the co-fired inductor provided by the specific embodiment of the present invention.
[0028] In the figure:
[0029] 1. winding; 2. cold pressing core; 3. magnet housing; 11. main body part; 12. connecting part; 13. limiting part; 14. accommodating part; 21. pressing body; 22. groove. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0030] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the following will describe the specific embodiments of the present invention in detail with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein. Those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.
[0031] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention.
[0032] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.
[0033] In the present invention, unless otherwise clearly specified and limited, the terms "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0034] In the present invention, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.
[0035] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.
[0036] This embodiment discloses a co-fired inductor and a processing method thereof, such as Figure 6 As shown, the co-fired inductor includes a winding 1, a cold pressed core 2 and a magnet housing 3, wherein the magnet housing 3 is at least partially wrapped around the outside of the winding 1 and the cold pressed core 2. In order to show the internal structure, Figure 6 The magnet housing 3 is drawn as transparent. In fact, it is not an additional restriction on the magnet housing 3. Depending on the different materials used, the magnet housing 3 can be transparent or non-transparent.
[0037] like Figure 3 Therefore, the winding 1 includes a U-shaped main body 11, and the two ends of the main body 11 are connected to the limiting part 13 through the connecting part 12, and the connected main body 11, connecting part 12 and limiting part 13 form a receiving part 14 with a U-shaped cross section. That is, the main body 11 is substantially parallel to the limiting part 13, and the connecting part 12 is substantially perpendicular to the main body 11 and the limiting part 13. It should be noted that "substantially parallel" and "substantially perpendicular" are not parallel and perpendicular in the strict sense. There may be a certain angle difference due to the limitation of processing accuracy, and a certain degree of deformation may occur in the user because the material used to prepare the winding 1 has the ability to deform.
[0038] like Figure 4 As shown, the cold pressed core 2 includes a block-shaped pressed body 21 and a groove 22 opened on the pressed body 21. Figure 3 and Figure 5 As shown, after installation, the pressing body 21 is located in the accommodating portion 14 , the main body 11 and the limiting portion 13 are respectively located on two opposite sides of the pressing body 21 , and the connecting portion 12 is completely embedded in the groove 22 .
[0039] In the co-fired inductor, the connection part 12 is completely embedded in the groove 22, and then the magnet housing 3 is formed on the outside of the winding 1 and the cold-pressed core 2. There is no exposed part on the winding 1, which reduces leakage magnetic flux, increases the working current, and improves the product inductance. The connection part 12 does not protrude from the cold-pressed core 2. The overall structure of the co-fired inductor is more compact, fully utilizes the material space, reduces the product size, and is conducive to the thinness of electronic products. The cold-pressed core 2 can support the main body 11 and the limit part 13, reducing the risk of bending and breaking the legs. The product electrode size is highly accurate and the product density is more uniform, which can meet the needs of miniaturization of electronic products.
[0040] like Figure 5 As shown, the winding 1 is made of a metal sheet, and the thickness of the metal sheet is less than the depth of the groove 22. It is ensured that after installation, the connecting portion 12 can be completely embedded in the groove 22, and will not protrude outside the groove 22 due to the thicker connecting portion 12.
[0041] The specific shape of the metal sheet used to prepare the winding 1 is not limited. Preferably, the cross section of the winding 1 is rectangular in the direction perpendicular to the plane where the winding 1 is located. Along the extension direction of the metal sheet, the shape and size of the cross section can be consistent, or it can be a special shape with different cross sections. Flat metal sheets have better ductility, and after bending, the shape is more regular and the size is more precise.
[0042] The winding 1 is preferably made of copper, silver or copper-silver alloy, which has good ductility and stable performance in an electromagnetic environment, thereby extending the service life of the co-fired inductor, making the working state of the electronic product more stable and providing a good user experience.
[0043] Based on the above structure, the outer surface of the winding 1 directly contacts the outer surface of the cold pressed core 2, and the outer surface of the winding 1 also directly contacts the inner surface of the magnet housing 3. That is, the outer surface of the winding 1 is not insulated.
[0044] The co-fired inductor includes one or more windings 1, and the specific number can be determined according to the use requirements. When the co-fired inductor includes multiple windings 1, all windings 1 are symmetrically connected to the cold-pressed core 2. The so-called "symmetry" includes but is not limited to central symmetry, midline symmetry, etc., which can minimize leakage magnetic field and compress volume.
[0045] The processing method of the co-fired inductor comprises the following steps:
[0046] Step S1: Figure 1 As shown in Figure 1, bend the metal sheet into a U shape. Figure 2 As shown in FIG. 1 , the metal sheet is bent once in a direction perpendicular to the plane in which it is located to form the main body 11 and the connecting part 12 of the winding 1. Figure 3 As shown, the connecting portion 12 is bent twice in a direction parallel to the plane where the main body 11 is located to form a limiting portion 13 , and a U-shaped accommodating portion 14 is formed between the main body 11 , the connecting portion 12 and the limiting portion 13 .
[0047] Step S2: Figure 4 As shown, a block-shaped pressed body 21 is prepared, and a groove 22 is formed on the pressed body 21 by synchronous pressing to obtain a cold pressed core 2;
[0048] Step S3: Figure 3 and Figure 5 As shown, the pressed body 21 is inserted into the receiving portion 14, and the connecting portion 12 is completely embedded in the groove 22;
[0049] Step S4: As shown in Figure 6 , after powder filling, form the magnet housing 3, and after sintering, obtain the co-fired inductor.
[0050] To further improve the product performance, after step S4, there is also step S5: impregnation, spraying, bending, and electroplating are carried out after sintering. Among them, the specific steps and parameters of impregnation, spraying, bending, and electroplating are the same as those in the prior art, and will not be elaborated here.
[0051] Based on the above processing method, the method for preparing the cold-pressed core 2 in step S2 is: applying a pressure of 1.3 t / cm 2 to the raw material by using a cold pressing process. After obtaining the shape of the cold-pressed core 2, preheating treatment is carried out. The heat treatment temperature is 150°C - 250°C, and the time is 5 minutes - 15 minutes. In this embodiment, the heat treatment temperature is 210°C, and the heat treatment time is 10 minutes. When applying pressure to the raw material by using a cold pressing process, other measurement units can also be used, for example, the cold pressing pressure is 100 Mpa - 500 Mpa. This is the first pressing and forming.
[0052] Based on the above processing method, the method for forming the magnet housing 3 after powder filling in step S4 is: putting the winding 1 and the cold-pressed core 2 into a mold, filling powder to the set amount, and applying a pressure of 16 t / cm 2 to the winding 1, the cold-pressed core 2, and the filled powder by using a cold pressing process. After cold pressing and forming, annealing is carried out. The annealing temperature is 580°C - 700°C, and the annealing time is 30 minutes - 120 minutes. In this embodiment, the annealing temperature is 660°C, and the annealing time is 30 minutes. This is the second pressing and forming.
[0053] The following is a specific embodiment:
[0054] Use a copper sheet to prepare the winding 1. The cross-sectional area of the copper sheet is 0.5 mm × 1 mm, the maximum external contour of the copper sheet is 5 mm × 4 mm × 2 mm, and the finished product size is 6.5 mm × 6.0 mm × 3.5 mm. The powder material used to prepare the magnet housing 3 is the FN + 15% FSA powder material with a magnetic permeability of 90, and the forming pressure is 16 T / cm 2 , and the sintering conditions are 660°C, 30 min, and nitrogen atmosphere.
[0055] Parameters of the finished product after molding: length 6.35 mm, width 5.82 mm, height 3.41 mm, initial inductance (L0) (nH) is 216, saturation (30 A) (nH) is 149.2, saturation (45 A) (nH) is 95.1, DC resistance (mΩ) is 0.633, insulation (kΩ) is 3 M, which fully meets the target values. Specifically, the target values are: maximum length 6.5 mm, maximum width 6.0 mm, maximum height 3.5 mm, initial inductance (L0) (nH) is 210 ± 20%, saturation (30 A) (nH) is at least 130, saturation (45 A) (nH) is at least 90, DC resistance (mΩ) is at most 0.7, insulation (kΩ) is > 1 K.
[0056] In addition to meeting the target values, compared with the prior art, the product formed by two - step molding has a significantly higher inductance value, higher and more uniform molding density, smaller electrode size tolerance, higher pressing density, and better formability than the product formed by one - step molding.
[0057] Note that the above is only the preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described here. Various obvious changes, re - adjustments, and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, it can also include more other equivalent embodiments, and the scope of the present invention is determined by the scope of the appended claims.
Claims
1. Co-fired inductor, It is characterized in that include: The winding (1) comprises a U-shaped main body (11), two ends of the main body (11) are respectively connected to a limiting part (13) through a connecting part (12), and the connected main body (11), the connecting part (12) and the limiting part (13) form a receiving part (14) with a U-shaped cross section; A cold pressed core (2), comprising a block-shaped pressed body (21) and a groove (22) provided on the pressed body (21), wherein the pressed body (21) is located in the accommodating portion (14), the main body (11) and the limiting portion (13) are respectively located on opposite sides of the pressed body (21), and the connecting portion (12) is completely embedded in the groove (22); and, A magnet housing (3) at least partially wraps around the outside of the winding (1) and the cold-pressed core (2).
2. The co-fired inductor according to claim 1, It is characterized in that The winding (1) is made of a metal sheet, the thickness of the metal sheet being smaller than the depth of the groove (22).
3. The co-fired inductor according to claim 1, It is characterized in that In a direction perpendicular to the plane where the winding (1) is located, the cross-section of the winding (1) is rectangular.
4. The co-fired inductor according to any one of claims 1 to 3, It is characterized in that The winding (1) is made of copper, silver or a copper-silver alloy.
5. The co-fired inductor according to any one of claims 1 to 3, It is characterized in that The outer surface of the winding (1) is directly in contact with the outer surface of the cold-pressed core (2) and the inner surface of the magnet housing (3).
6. The co-fired inductor according to any one of claims 1 to 3, It is characterized in that The co-fired inductor comprises one or more windings (1), and all the windings (1) are symmetrically connected to the cold pressed core (2).
7. Processing method of co-fired inductor, It is characterized in that The steps include: Step S1: bending a metal sheet into a U-shape, bending the metal sheet once in a direction perpendicular to the plane where the metal sheet is located to form a main body (11) and a connecting portion (12) of the winding (1), bending the connecting portion (12) twice in a direction parallel to the plane where the main body (11) is located to form a limiting portion (13), and forming a U-shaped accommodating portion (14) between the main body (11), the connecting portion (12) and the limiting portion (13); Step S2: preparing a block-shaped pressed body (21), and simultaneously pressing to form a groove (22) on the pressed body (21) to obtain a cold pressed core (2); Step S3: inserting the pressed body (21) into the accommodating portion (14), and the connecting portion (12) is completely embedded in the groove (22); Step S4: After filling with powder, a magnet housing (3) is formed, and after sintering, the co-fired inductor is obtained.
8. The method for processing a co-fired inductor according to claim 7, It is characterized in that After step S4, step S5 is also included: impregnation, spraying, bending and electroplating are performed after sintering.
9. The method for processing a co-fired inductor according to claim 7, It is characterized in that The method for preparing the cold-pressed core (2) in step S2 is as follows: applying a pressure of 1.3 t / cm 2 to the raw material by a cold pressing process, and after obtaining the shape of the cold-pressed core (2), performing a preheating treatment, where the heat treatment temperature is 150°C - 250°C and the time is 5 minutes - 15 minutes.
10. The processing method of the co-fired inductor according to claim 7, characterized in that, in step S4, the method of forming the magnet housing (3) after powder filling is: putting the winding (1) and the cold pressing core (2) into a mold, filling powder to a set amount, applying a pressure of 16 t / cm2 to the winding (1), the cold pressing core (2) and the filled powder by using a cold pressing process, annealing after cold pressing forming, the annealing temperature is 580°C - 700°C, and the annealing time is 30 minutes - 120 minutes.