Low-loss copper-iron co-fired integrated inductor and preparation method thereof

Abstract

The invention provides a low-loss copper-iron co-fired integrated inductor and a preparation method thereof.The low-loss copper-iron co-fired integrated inductor is characterized in that the low-loss copper-iron co-fired integrated inductor comprises a middle punched and bent copper sheet and magnetic powder wrapping the copper sheet, and the copper sheet comprises a first bent part, second bent parts extending from the two ends of the first bent part towards the same side and third bent parts extending outwards from the second bent parts; a welding terminal is fixedly arranged at one end, far away from the second bending part, of the third bending part; the second bending part is perpendicular to the first bending part, the third bending part is parallel to the first bending part, the length of the first bending part is larger than that of the third bending part, and specifically, by the adoption of the completely-shielded design structure, the inductor can have higher electromagnetic property and lower loss.

Description

Technical Field

[0001] The present invention belongs to the technical field of inductor processing, and in particular relates to a low-loss copper-iron co-fired integrated inductor and a preparation method thereof. Background Art

[0002] Copper-iron co-fired inductors are a new type of inductor component manufactured using a mixed sintering process of copper and iron. Combining the advantages of both copper and iron, these inductors offer numerous advantages, including high energy density, compact size, high capacitance, and low resistance. Consequently, they are widely used in various electronic devices.

[0003] At present, copper-iron co-fired inductors mostly adopt a design of directly leading out the copper sheet and then folding it at an angle. This structural design has a large leakage flux and a small effective magnetic circuit area, which is not conducive to the electromagnetic characteristics of the copper-iron co-fired inductor. In addition, this design structure has poor shielding effect, causing magnetic radiation to surrounding components, thereby affecting the performance of the components. Summary of the Invention

[0004] Based on this, an embodiment of the present invention provides a low-loss copper-iron co-fired integrated inductor and a preparation method thereof, aiming to reduce the loss of the copper-iron co-fired inductor and improve the electromagnetic performance of the copper-iron co-fired inductor.

[0005] A first aspect of an embodiment of the present invention provides a low-loss copper-iron co-fired inductor, comprising a centrally stamped and bent copper sheet and magnetic powder coating the copper sheet, wherein the copper sheet includes a first bent portion, second bent portions extending toward the same side from both ends of the first bent portion, and a third bent portion extending outward from the second bent portion, wherein a solder terminal is fixedly disposed at one end of the third bent portion away from the second bent portion;

[0006] The second bending portion is perpendicular to the first bending portion, the third bending portion is parallel to the first bending portion, and the length of the first bending portion is greater than that of the third bending portion.

[0007] Furthermore, the copper sheet has a width of 1 mm to 3 mm and a thickness of 0.5 mm to 1.5 mm.

[0008] Furthermore, the magnetic powder is one or a mixture of iron silicon, iron silicon chromium, iron silicon aluminum, and iron nickel.

[0009] Furthermore, the material of the welding terminal is copper-nickel-tin.

[0010] Furthermore, the low-loss copper-iron co-fired inductor is block-shaped or column-shaped.

[0011] Furthermore, the surface of the magnetic powder is sprayed with anti-rust paint.

[0012] A second aspect of an embodiment of the present invention provides a method for preparing a low-loss copper-iron co-fired inductor, which is used to prepare the low-loss copper-iron co-fired inductor. The method comprises:

[0013] Providing a material strip, on which stamped and bent copper sheets are arranged at intervals;

[0014] Put the copper sheet into the mold, fill it with powder and press it to get the formed inductor;

[0015] The inductor is placed in an atmosphere sintering furnace for sintering, and then cut and the terminals are drawn out;

[0016] Electroplating copper-nickel-tin at the terminals yields solder terminals.

[0017] Furthermore, after the step of placing the inductor into an atmosphere sintering furnace for sintering, the method further includes:

[0018] The sintered inductor surface is sprayed with anti-rust paint, and then cut and lead out the terminals;

[0019] Strip off the anti-rust paint on the terminals to expose the terminals;

[0020] Electroplating copper-nickel-tin at the terminals yields solder terminals.

[0021] Furthermore, the powder filling and pressing process is carried out at room temperature, with a pressure of 2200 MPa and a pressure holding time of 5 seconds.

[0022] Furthermore, the inductor is placed in an atmosphere sintering furnace for sintering at a temperature of 750° C. to 800° C., a sintering time of 1 hour, an atmosphere of nitrogen and hydrogen, and a gas flow ratio of N2:H2=3:1.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The copper sheet is formed by a centrally stamped and bent copper sheet and magnetic powder covering the copper sheet. The copper sheet includes a first bent portion, a second bent portion extending toward the same side from both ends of the first bent portion, and a third bent portion extending outward from the second bent portion. A welding terminal is fixed to one end of the third bent portion away from the second bent portion. The second bent portion is perpendicular to the first bent portion, the third bent portion is parallel to the first bent portion, and the length of the first bent portion is greater than that of the third bent portion. Specifically, the above-mentioned fully shielded design structure can make the inductor have higher electromagnetic characteristics and lower loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic structural diagram of a low-loss copper-iron co-fired inductor proposed in an embodiment of the present invention;

[0026] Figure 2This is a flow chart for implementing a method for preparing a low-loss copper-iron co-fired inductor proposed in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the structure of the co-fired inductor after the strip and molded block are formed;

[0028] Figure 4 Schematic diagram of the structure of the copper-iron co-fired inductor prepared in Example 1 of the present invention;

[0029] Figure 5 Schematic diagram of the structure of the copper-iron co-fired inductor prepared in Example 2 of the present invention.

[0030] The following specific implementation manner will be further described in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0031] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The drawings illustrate several embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present invention.

[0032] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] See also Figure 1 , is a schematic structural diagram of a low-loss copper-iron co-fired inductor proposed in an embodiment of the present invention. The low-loss copper-iron co-fired inductor includes a central stamped and bent copper sheet and magnetic powder covering the copper sheet. The magnetic powder is a mixture of one or more of iron silicon, iron silicon chromium, iron silicon aluminum, and iron nickel. The copper sheet includes a first bent portion 1, a second bent portion 2 extending toward the same side from both ends of the first bent portion 1, and a third bent portion 3 extending outward from the second bent portion 2. A welding terminal is fixed to the end of the third bent portion 3 away from the second bent portion 2, and the material of the welding terminal is copper-nickel-tin.

[0035] Specifically, the second bend 2 is perpendicular to the first bend 1, the third bend 3 is parallel to the first bend 1, and the length of the first bend 1 is greater than the length of the third bend 3. It can be understood that the inductor design that directly leads out the copper sheet and then folds the angle has a large leakage flux, and the small magnetic circuit it forms is small, which is not conducive to the performance of the co-fired inductor. This scheme adopts a "J"-shaped fully shielded design structure, and the inductor has higher electromagnetic characteristics. It should be noted that the "J"-shaped embedded structure has less leakage flux and a larger effective magnetic circuit interface than the "I" straight-out pin structure, which is beneficial to improving the overall electromagnetic performance of the inductor. The length of the third bend ranges from 1 mm to 1.5 mm. For example, the length of the third bend is 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, and 1.5 mm, but is not limited thereto. The length of the second bend ranges from 2 mm to 4.5 mm. For example, the length of the second bend is 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, and 4.5 mm, but is not limited thereto. The length of the first bend ranges from 3 mm to 5 mm. For example, the length of the first bend is 3 mm, 3.5 mm, 4 mm, 4.5 mm, and 5 mm, but is not limited thereto. Preferably, the length ratio of the third bend, the second bend, and the first bend is 1:3.5:3.

[0036] It should be noted that the traditional angled design limits the thickness of the copper sheet. A copper sheet that is too thick is difficult to fold as a lead-out terminal. In this solution, the electrode is led out by cutting the side legs and then electroplating. The thickness design of the copper sheet is not limited. Specifically, the width of the copper sheet is 1 mm to 3 mm, and the thickness is 0.5 mm to 1.5 mm. It can be understood that the size of the copper sheet can be calculated based on the DCR and the bendability of the copper sheet. In the embodiment of the present invention, the width of the copper sheet is 2 mm and the thickness is 0.8 mm.

[0037] In addition, the low-loss copper-iron co-fired inductor is in block or column shape, and anti-rust paint is sprayed on the surface of the magnetic powder to prevent rust.

[0038] Currently, there are few solutions for continuous production of single copper sheet inductor die forming. This solution uses a stamping strip solution to solve the problem of continuous automated forming. Please refer to Figure 2 , is a flow chart for implementing a method for preparing a low-loss copper-iron co-fired inductor proposed in an embodiment of the present invention, wherein the preparation method includes the following steps:

[0039] Step S01: providing a material strip, on which stamped and bent copper sheets are arranged at intervals.

[0040] For details, please refer to Figure 3, is a structural diagram of the co-fired inductor after the material strip and the molded block are formed. Positioning holes 5 are opened on the material strip 4, and reinforcing ribs 6 are arranged at intervals on the material strip 4. The reinforcing ribs 6 also play a limiting role. It can be understood that the reinforcing ribs 6 are fixedly connected to the stamped and bent copper sheet.

[0041] Step S02: placing the copper sheet into a mold, filling it with powder and pressing it to obtain a formed inductor.

[0042] It should be noted that the powder filling and pressing process is carried out at room temperature, with a pressure of 2200 MPa and a pressure holding time of 5 seconds. The magnetic powder used is one or a mixture of iron silicon, iron silicon chromium, iron silicon aluminum, and iron nickel.

[0043] Step S03: placing the inductor into an atmosphere sintering furnace for sintering, and then cutting it to lead out the terminals.

[0044] The sintering temperature is 750° C. to 800° C., the sintering time is 1 hour, the atmosphere is nitrogen and hydrogen, and the gas flow ratio is N2:H2=3:1.

[0045] Step S04: electroplating copper-nickel-tin at the terminal to obtain a welding terminal.

[0046] In some other embodiments of the present invention, after the step of placing the inductor into an atmosphere sintering furnace for sintering, the step further includes:

[0047] The surface of the sintered inductor 7 is sprayed with anti-rust paint, and then cut and lead-out terminals are performed;

[0048] Strip off the anti-rust paint on the terminals to expose the terminals;

[0049] Electroplating copper-nickel-tin at the terminals yields solder terminals.

[0050] To facilitate understanding of the present invention, several embodiments of the present invention are provided below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive disclosure of the present invention.

[0051] Example 1

[0052] In this embodiment 1, a method for preparing a low-loss copper-iron co-fired inductor is provided, the method comprising:

[0053] A material strip is provided, on which stamped and bent copper sheets are arranged at intervals. The copper sheet includes a first bend 1, a second bend 2 extending toward the same side from both ends of the first bend 1, and a third bend 3 extending outward from the second bend 2. A soldering terminal is fixed to one end of the third bend 3 away from the second bend 2. The second bend 2 is perpendicular to the first bend 1, and the third bend 3 is parallel to the first bend 1. The length of the first bend 1 is greater than that of the third bend 3. The copper sheet has a width of 2 mm and a thickness of 0.8 mm.

[0054] The copper sheet is placed in a mold, filled with powder and pressed to obtain a formed inductor. The magnetic powder used is iron silicon. The powder filling and pressing process is carried out at room temperature, with a pressure of 2200 MPa and a pressure holding time of 5 seconds.

[0055] The inductor is placed in an atmosphere sintering furnace for sintering at a temperature of 780°C for 1 hour in a nitrogen and hydrogen atmosphere with a gas flow ratio of N2:H2=3:1. The surface of the sintered inductor is then sprayed with anti-rust paint and cut to remove the terminals.

[0056] Strip off the anti-rust paint on the terminals to expose the terminals;

[0057] Electroplating copper-nickel-tin at the terminals to obtain welding terminals, and finally preparing a block of copper-iron co-fired inductor, please refer to Figure 4 , is a schematic structural diagram of the copper-iron co-fired inductor prepared in Example 1 of the present invention, wherein the length of the third bent portion 3 is 1.2 mm, the length of the second bent portion 2 is 4.2 mm, the length of the first bent portion 1 is 3.6 mm, and the length ratio of the third bent portion 3, the second bent portion 2 and the first bent portion 1 is 1:3.5:3.

[0058] Example 2

[0059] In this embodiment 2, a method for preparing a low-loss copper-iron co-fired integrated inductor is provided. The difference from the embodiment 1 is that the shape of the copper-iron co-fired integrated inductor finally prepared is cylindrical. Figure 5 , which is a structural diagram of the copper-iron co-fired integrated inductor prepared in Example 2 of the present invention. It should be noted that, compared with the square design, the columnar design eliminates the dead-angle magnetic phase area of the corner magnetic circuit, which is beneficial to reducing losses.

[0060] Comparative Example 1

[0061] In this comparative example 1, a method for preparing a copper-iron co-fired integrated inductor is provided. The difference from Example 1 is that it is prepared using a traditional process, using molding with a pressure of 2200 MPa and a sintering temperature of 780°C. The copper sheet is in the shape of an "I" and is directly led out. The width of the copper sheet is 4 mm and the thickness is 0.4 mm.

[0062] Comparative Example 2

[0063] In this comparative example 2, a method for preparing a copper-iron co-fired integrated inductor is provided. The difference from Example 2 is that it is prepared using a traditional process, using compression molding with a pressure of 2200 MPa and a sintering temperature of 780°C. The final copper sheet is in the shape of an "I" and is directly led out. The width of the copper sheet is 4 mm and the thickness is 0.4 mm.

[0064] Example 3

[0065] The difference between this embodiment 3 and embodiment 2 is that the lengths of the first bending portion, the second bending portion and the third bending portion are different. Specifically, in embodiment 3, the length of the third bending portion is 1 mm, the length of the second bending portion is 2 mm, and the length of the first bending portion is 3 mm.

[0066] Example 4

[0067] The difference between this embodiment 4 and embodiment 2 is that the lengths of the first bending portion, the second bending portion and the third bending portion are different. Specifically, in embodiment 4, the length of the third bending portion is 1.5 mm, the length of the second bending portion is 4.5 mm, and the length of the first bending portion is 5 mm.

[0068] Example 5

[0069] The difference between this embodiment 5 and embodiment 2 is that the lengths of the first bending portion, the second bending portion and the third bending portion are different. Specifically, in embodiment 5, the length of the third bending portion is 1 mm, the length of the second bending portion is 4.2 mm, and the length of the first bending portion is 3.6 mm.

[0070] Example 6

[0071] The difference between Example 6 and Example 2 is that the lengths of the first bending portion, the second bending portion and the third bending portion are different. Specifically, in Example 6, the length of the third bending portion is 1.5 mm, the length of the second bending portion is 4.2 mm, and the length of the first bending portion is 3.6 mm.

[0072] Example 7

[0073] The difference between this embodiment 7 and embodiment 2 is that the lengths of the first bending portion, the second bending portion and the third bending portion are different. Specifically, in embodiment 7, the length of the third bending portion is 1.2 mm, the length of the second bending portion is 2 mm, and the length of the first bending portion is 3.6 mm.

[0074] Example 8

[0075] The difference between this embodiment 8 and embodiment 2 is that the lengths of the first bending portion, the second bending portion and the third bending portion are different. Specifically, in embodiment 8, the length of the third bending portion is 1.2 mm, the length of the second bending portion is 3 mm, and the length of the first bending portion is 3.6 mm.

[0076] Example 9

[0077] The difference between this embodiment 9 and embodiment 2 is that the lengths of the first bending portion, the second bending portion and the third bending portion are different. Specifically, in embodiment 9, the length of the third bending portion is 1.2 mm, the length of the second bending portion is 4 mm, and the length of the first bending portion is 3.6 mm.

[0078] Example 10

[0079] The difference between this embodiment 10 and embodiment 2 is that the lengths of the first bending portion, the second bending portion and the third bending portion are different. Specifically, in embodiment 10, the length of the third bending portion is 1.2 mm, the length of the second bending portion is 4.5 mm, and the length of the first bending portion is 3.6 mm.

[0080] Example 11

[0081] The difference between this embodiment 11 and embodiment 2 is that the lengths of the first bending portion, the second bending portion and the third bending portion are different. Specifically, in embodiment 11, the length of the third bending portion is 1.2 mm, the length of the second bending portion is 4.2 mm, and the length of the first bending portion is 3 mm.

[0082] Example 12

[0083] The difference between this embodiment 12 and embodiment 2 is that the lengths of the first bending portion, the second bending portion and the third bending portion are different. Specifically, in embodiment 12, the length of the third bending portion is 1.2 mm, the length of the second bending portion is 4.2 mm, and the length of the first bending portion is 4 mm.

[0084] Example 13

[0085] The difference between this embodiment 13 and embodiment 2 is that the lengths of the first bending portion, the second bending portion and the third bending portion are different. Specifically, in embodiment 13, the length of the third bending portion is 1.2 mm, the length of the second bending portion is 4.2 mm, and the length of the first bending portion is 5 mm.

[0086] Example 14

[0087] The difference between this embodiment 14 and embodiment 2 is that the lengths of the first bending portion, the second bending portion and the third bending portion are different. Specifically, in embodiment 14, the length of the third bending portion is 1 mm, the length of the second bending portion is 3.5 mm, the length of the first bending portion is 3 mm, and the length ratio of the third bending portion, the second bending portion and the first bending portion is 1:3.5:3.

[0088] Example 15

[0089] In this embodiment 15, the difference from embodiment 2 is that the lengths of the first bending portion, the second bending portion and the third bending portion are different. Specifically, in embodiment 14, the length of the third bending portion is 1.1 mm, the length of the second bending portion is 3.85 mm, the length of the first bending portion is 3.3 mm, and the length ratio of the third bending portion, the second bending portion and the first bending portion is 1:3.5:3.

[0090] It should be noted that the performance test of the copper-iron co-fired inductor prepared above was carried out, and the inductor performance parameters were compared, as shown in Table 1:

[0091] Table 1

[0092]

[0093] The data shows that the copper-iron co-fired inductor prepared in Example 2 of the present invention has the best performance. In addition, when the length ratio of the third bend, the second bend, and the first bend is 1:3.5:3, the performance of the copper-iron co-fired inductor is better than others. Specifically, the inductance L remains at a high level, the L (nH) @ 80A decreases significantly, and the loss is small.

[0094] In summary, the present invention provides a low-loss copper-iron co-fired inductor and a preparation method thereof, through a centrally stamped and bent copper sheet and magnetic powder covering the copper sheet, the copper sheet includes a first bent portion, a second bent portion extending toward the same side from both ends of the first bent portion, and a third bent portion extending outward from the second bent portion, and a welding terminal is fixedly provided at one end of the third bent portion away from the second bent portion; the second bent portion is perpendicular to the first bent portion, the third bent portion is parallel to the first bent portion, and the length of the first bent portion is greater than the length of the third bent portion. Specifically, the above-mentioned fully shielded design structure can be used to make the inductor have higher electromagnetic characteristics and lower losses.

[0095] The above is a detailed introduction to a low-loss copper-iron co-fired inductor and its preparation method provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

[0096] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similarities between the various embodiments can be referred to in conjunction with each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and relevant details can be referred to the method description.

[0097] It should also be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that the process, method, article, or apparatus comprising a series of elements inherent to the elements, or also including elements inherent to these processes, methods, articles, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0098] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A low-loss copper-iron co-fired inductor, characterized in that: The invention comprises a centrally punched and bent copper sheet and magnetic powder covering the copper sheet, wherein the copper sheet comprises a first bent portion, a second bent portion extending from both ends of the first bent portion toward the same side, and a third bent portion extending outward from the second bent portion, wherein a welding terminal is fixedly provided at one end of the third bent portion away from the second bent portion; The second bending portion is perpendicular to the first bending portion, the third bending portion is parallel to the first bending portion, and the length of the first bending portion is greater than that of the third bending portion.

2. The low-loss copper-iron co-fired inductor according to claim 1, characterized in that: The copper sheet has a width of 1 mm to 3 mm and a thickness of 0.5 mm to 1.5 mm.

3. The low-loss copper-iron co-fired inductor according to claim 1, characterized in that: The magnetic powder is one of iron silicon, iron silicon chromium, iron silicon aluminum and iron nickel, or a mixture of several of them.

4. The low-loss copper-iron co-fired inductor according to claim 1, characterized in that: The material of the welding terminal is copper-nickel-tin.

5. The low-loss copper-iron co-fired inductor according to claim 1, characterized in that: The low-loss copper-iron co-fired inductor is in block or column shape.

6. The low-loss copper-iron co-fired inductor according to claim 1, characterized in that: The surface of the magnetic powder is sprayed with anti-rust paint.

7. A method for preparing a low-loss copper-iron co-fired inductor, characterized in that: The method for preparing the low-loss copper-iron co-fired inductor according to any one of claims 1 to 6 comprises: Providing a material strip, on which stamped and bent copper sheets are arranged at intervals; Put the copper sheet into the mold, fill it with powder and press it to get the formed inductor; The inductor is placed in an atmosphere sintering furnace for sintering, and then cut and the terminals are drawn out; Electroplating copper-nickel-tin at the terminals yields solder terminals.

8. The method for preparing a low-loss copper-iron co-fired inductor according to claim 7, characterized in that: After the step of placing the inductor into an atmosphere sintering furnace for sintering, the following steps are further included: The sintered inductor surface is sprayed with anti-rust paint, and then cut and lead out the terminals; Strip off the anti-rust paint on the terminals to expose the terminals; Electroplating copper-nickel-tin at the terminals yields solder terminals.

9. The method for preparing a low-loss copper-iron co-fired inductor according to claim 8, characterized in that: The powder filling and pressing process is carried out at room temperature, with a pressure of 2200 MPa and a pressure holding time of 5 seconds.

10. The method for preparing a low-loss copper-iron co-fired inductor according to claim 9, characterized in that: When the inductor is placed in an atmosphere sintering furnace for sintering, the sintering temperature is 750℃~800℃, the sintering time is 1h, the atmosphere is nitrogen and hydrogen, and the gas flow ratio is N2:H2=3:1.

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