An integrally molded inductor structure with a top-covered conductor and its preparation process

Abstract

The present invention discloses an integrally formed die-cast inductor structure with a conductor coated on the top and a preparation process thereof, comprising a material preparation step: an enameled wire coil is wound inside the die-cast inductor body, and the end edge of the enameled wire coil is exposed outside the die-cast inductor body; an insulating paint coating step: a layer of insulating paint is coated on the outer surface of the die-cast inductor body; a laser engraving step of an external electrode area: a laser source is used to remove the insulating paint in the external electrode setting area; a grinding and removal step: a grinding device is used to further remove the side of the die-cast inductor body corresponding to the end edge of the enameled wire; a copper layer, a nickel layer and a tin layer electroplating step: a copper layer, a nickel layer and a tin layer are plated in the external electrode setting area and the grinding and removal area in sequence by electroplating. Through the above method, the present invention coats a conductive layer on the top of the integrally formed die-cast inductor, and guides the conductive layer to the bottom to form an electrode, and the electrode can be grounded to the PCB, thereby guiding the redundant electromagnetic interference to the grounding end, effectively reducing the interference to the circuit.

Description

Technical Field

[0001] The present invention relates to the field of preparation of an integrally formed die-cast inductor, and in particular to an integrally formed die-cast inductor structure with a top-coated conductor and a preparation process thereof. Background Art

[0002] Inductor is an important component in the circuit, which can achieve functions such as filtering, energy storage, and resonance. With the miniaturization of electronic products and high-density assembly of components, inductor components have developed rapidly. In addition, considering electromagnetic compatibility, eliminating electromagnetic interference of electronic products has become an important requirement for electronic products.

[0003] The chip-type integrally formed die-cast inductor in the prior art includes a coil formed by winding enameled wire at the center, a magnetic metal powder is pressed around the coil to form an iron core, and then a layer of polymer coating is coated as a protective layer. Metal conductive paste is printed on the two ends of the iron core as an electrode bottom layer to connect the internal coil, and finally electroplated with nickel, tin and other metals so that it can be quickly soldered on the circuit board using a surface adhesive method.

[0004] In the above structure, the outermost polymer coating of the magnetic core is only for weather protection. In actual application, there may be some situations where the magnetic field interferes with the line signal or surrounding components due to factors such as circuit design, application conditions, magnetic materials or structural design. For example, the inductor originally selected by the customer will interfere with the signal under the PCB when used. At this time, the circuit design and inductor must be readjusted to meet safety regulations, and usually each related component needs to be adjusted, which is cumbersome and time-consuming, affecting customer satisfaction. Summary of the invention

[0005] The main technical problem solved by the present invention is to provide an integrally formed molded inductor structure with a conductor covered on the top and a preparation process thereof. A conductive layer is coated on the top of the chip-type integrally formed molded inductor, and the conductive layer is guided to the bottom to form an electrode. The electrode can be grounded to the PCB, thereby guiding the excess electromagnetic interference to the ground terminal, effectively reducing the interference to the circuit. If the magnetic field interferes with the circuit signal or surrounding components due to factors such as circuit design, application conditions, and structural design during use, there is no need to readjust the circuit design and related components, which is convenient and practical. On the other hand, since the interference on the top of the component can be guided away by the ground terminal, the components above the component can be further shortened from the inductor to reduce the height of the finished product.

[0006] In order to solve the above technical problems, a technical solution adopted by the present invention is: to provide an integrally formed die-cast inductor structure with a top-covered conductor, comprising a die-cast inductor body, an enameled wire coil is wound at the inner central position of the die-cast inductor body, the end edges of both ends of the enameled wire coil are exposed on the outer surface of the die-cast inductor body, the outer surface of the die-cast inductor body is provided with a copper layer, and the copper layer is distributed in the outer electrode setting area of ​​the outer surface of the die-cast inductor body, the outer electrode setting area comprises a first outer electrode setting area and a second outer electrode setting area, the first outer electrode setting area is a rectangular area located at both ends of one side of the die-cast inductor body and used to respectively correspond to the internal enameled wire coil, the second outer electrode setting area is a rectangular area located between adjacent first outer electrode setting areas and not connected to the internal enameled wire coil, the second outer electrode setting area comprises a second outer electrode main setting area and a second outer electrode grounding setting area for grounding function, the second outer electrode main setting area and the second outer electrode grounding setting area are connected, the non-copper layer covering area of ​​the outer surface of the die-cast inductor body is provided with an insulating paint, and the outer surface of the copper layer is provided with a nickel layer and a tin layer in sequence.

[0007] A process for preparing an integrally molded inductor with a top-coated conductor comprises the following steps:

[0008] Material preparation step S1: preparing a die-cast inductor body to be processed, wherein the die-cast inductor body is die-casted from magnetic powder, a circular enameled wire coil is wound around the center of the die-cast inductor body, and the end edges of both ends of the enameled wire coil are exposed on the outer surface of the die-cast inductor body;

[0009] Insulating varnish coating step S2: coating a layer of insulating varnish on the outer surface of the die-cast inductor body obtained in S1 above;

[0010] Laser engraving the outer electrode area step S3: using a laser source to remove the insulating paint in the outer electrode setting area, thereby exposing the molded inductor in the outer electrode setting area.

[0011] Grinding and removing step S4: using a grinding device to further remove the side surfaces of the die-cast inductor corresponding to the two end edges of the enameled wire in the die-cast inductor obtained in S3, thereby further exposing the two end edges of the enameled wire coil;

[0012] Electroplating copper layer step S5: electroplating a copper layer on the outer electrode setting area in the above S3 and the grinding and removal area in the above S4;

[0013] Electroplating nickel and tin layer step S6: Similarly, a nickel layer and a tin layer are plated in sequence on the copper layer electroplated in the above S5 by electroplating, thus completing the preparation process of the integral molded inductor with the top covered conductor.

[0014] Preferably, the molded inductor body in the material preparation step S1 is formed by die-casting soft magnetic powder with a particle size of 1 to 100 um mixed with an organic resin.

[0015] Preferably, the soft magnetic powder is any one of reduced iron powder, atomized iron powder, iron-nickel powder, iron-silicon-aluminum powder, iron-silicon-chromium powder or iron-silicon powder.

[0016] Preferably, the content of the organic resin is 0.5% to 10%.

[0017] Preferably, the insulating varnish in the insulating varnish coating step S2 is any one of epoxy resin, acrylic resin, phenolic resin and silicone resin.

[0018] Preferably, in the grinding and removing step S4, the side surfaces of the die-cast inductor body corresponding to the end edges of both ends of the enameled wire are removed with a thickness of 0.01 mm to 0.1 mm.

[0019] Preferably, in the copper layer electroplating step S5, the electroplating thickness of the copper layer is 1 μm to 10 μm.

[0020] Preferably, in the step S6 of electroplating nickel and tin layers, the electroplating thickness of the nickel layer is 1 μm to 10 μm, and the electroplating thickness of the tin layer is 1 μm to 10 μm.

[0021] The beneficial effects of the present invention are:

[0022] The present invention provides an integrally formed molded inductor structure with a conductor coated on the top and a preparation process thereof. A conductive layer is coated on the top of the chip-type integrally formed molded inductor, and the conductive layer is guided to the bottom to form an electrode. The electrode can be grounded to a PCB, thereby guiding excess electromagnetic interference to the ground terminal, effectively reducing interference with the circuit. If the magnetic field interferes with the circuit signal or surrounding components due to factors such as circuit design, application conditions, and structural design during use, there is no need to readjust the circuit design and related components, which is convenient and practical. On the other hand, since the interference on the top of the component can be guided away by the ground terminal, the components above the component can be further shortened from the distance to the inductor to reduce the height of the finished product. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is an integrally formed molded inductor structure with a top-covered conductor and its preparation

[0024] Schematic diagram of the process steps;

[0025] Figure 2 is a cross-sectional schematic diagram of an integrally formed molded inductor obtained through the material preparation step S1 in the present invention;

[0026] Figure 3The cross section of the integral molded inductor obtained after the insulating paint coating step S2 in the present invention is

[0027] Schematic diagram;

[0028] Figure 4 The one-piece molded electrode is obtained after the laser engraving of the outer electrode area step S3 in the present invention.

[0029] Schematic diagram of the cross section of the sensor;

[0030] Figure 5 yes Figure 4 The three-dimensional structure corresponding to the state is used to reflect the second outer electrode setting area;

[0031] Figure 6 yes Figure 4 The three-dimensional structure on the other side corresponding to the state is used to reflect the first external electrode setting

[0032] region, a second outer electrode grounding setting region;

[0033] Figure 7 is the cross section of the integral molded inductor in the state of grinding and removing step S4 in the present invention.

[0034] Surface schematic diagram;

[0035] Figure 8 yes Figure 7 The cross-section of the integral molded inductor obtained after grinding and removing step S4 is shown in FIG.

[0036] intention;

[0037] Fig. 9 The cross-section of the integral molded inductor obtained after the copper electroplating step S5 in the present invention is shown in FIG.

[0038] intention;

[0039] Fig.10 The one-piece molded inductor is obtained after the nickel and tin layer electroplating step S6 in the present invention.

[0040] Schematic cross section.

[0041] The markings of the components in the accompanying drawings are as follows:

[0042] 1. Die-cast inductor body; 2. Enameled wire coil; 2-A. End edge; 2-B. End edge; 3. Insulating varnish; 4-A. First external electrode setting area; 4-B1. Second external electrode main setting area; 4-B2. Second external electrode grounding setting area; 5. Copper layer; 6. Nickel layer; 7. Tin layer;

[0043] S1, material preparation step; S2, insulating paint coating step; S3, laser engraving outer electrode area step; S4, grinding and then removing step; S5, copper electroplating step; S6, nickel and tin electroplating step. DETAILED DESCRIPTION

[0044] The preferred embodiments of the invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the invention.

[0045] Example:

[0046] like Figure 1 and Figure 2 As shown, an integrally formed die-cast inductor structure with a top-covered conductor and its preparation process include a material preparation step S1: preparing a die-cast inductor body 1 to be processed, the die-cast inductor body 1 is formed by die-casting a mixture of soft magnetic powder and organic resin, wherein: the particle size range of the soft magnetic powder is 1 to 100 um, and within this particle size range, the density of the soft magnetic powder is increased due to the difference in particle size, thereby improving the inductance characteristics; the soft magnetic powder is any one of reduced iron powder, atomized iron powder, iron-nickel powder, iron-silicon-aluminum powder, iron-silicon-chromium powder or iron-silicon powder, and the preferred content of the organic resin is 0.5 to 10%. A coil is wound around the center of the die-cast inductor body 1, and the coil is a circular enameled wire coil 2, and the end edges 2-A and 2-B at both ends of the enameled wire coil 2 are drawn out of the die-cast inductor body 1 and are both exposed on the outer surface of the die-cast inductor body 1.

[0047] like Figure 1 and Figure 3 As shown, insulating paint coating step S2: a layer of insulating paint 3 is coated on the outer surface of the molded inductor body 1 obtained in step S1, and the insulating paint 3 is any one of epoxy resin, acrylic resin, phenolic resin, and silicone resin. The spraying method of the insulating paint 3 is any one of roller spraying, normal pressure impregnation, vacuum impregnation, and high pressure impregnation. The setting of the insulating paint 3 plays a protective effect and maintains sufficient inductance characteristics.

[0048] like Figure 4 , 5As shown in Figure 6, laser engraving the external electrode area step S3: use a laser source to remove the insulating paint 3 in the external electrode setting area, and this removal position is the area where the external electrode is set later. The external electrode setting area includes a rectangular first external electrode setting area 4-A located at both ends of one side of the molded inductor body 1 and used to respectively connect the internal enameled wire coil 2, and a rectangular second external electrode setting area located between adjacent first external electrode setting areas 4-A and not connected to the internal enameled wire coil 2. The second external electrode setting area includes a second external electrode main setting area 4-B1 and a second external electrode grounding setting area 4-B2 for grounding function, and the second external electrode main setting area 4-B1 and the second external electrode grounding setting area 4-B2 are connected. After the subsequent electroplating is completed, the second external electrode grounding setting area 4-B2 is used for grounding. If the second external electrode grounding setting area 4-B2 and the PCB are grounded, the electric and magnetic field interference generated when the component is operating can be conducted away by the second external electrode grounding setting area 4-B2; in addition, since the interference at the top of the component has been conducted away by the grounding end, other components above the component can further shorten the distance from the inductor, thereby reducing the height of the finished product.

[0049] like Figure 1 and Figure 7 As shown, grinding and removing step S4: using a grinding device to further remove the side surfaces of the die-cast inductor corresponding to the end edges 2-A and 2-B of the enameled wire coil 2 at both ends of the die-cast inductor obtained in step S3, as shown in FIG. Figure 7 As shown in the middle C area, the two end edges 2-A and 2-B of the enameled wire coil 2 are further exposed. In this step, the thickness of the side molded inductor body removed is 0.01mm to 0.1mm. This removal range can fully expose the enameled wire 2 and retain the inductance characteristics. The product state obtained after the above steps is as follows Figure 8 shown.

[0050] like Figure 1 and Fig. 9 As shown, the copper layer electroplating step S5: the copper layer 5 is electroplated on the external electrode setting area in the above S3 and the area that is ground and removed in the above S4, and the electroplating thickness of the copper layer 5 is 1μm~10μm. The setting of the copper layer 5 can greatly increase the contact area between the two end edges 2-A, 2-B of the coil 2 and the subsequent nickel electroplating layer.

[0051] like Figure 1 and Fig.10As shown, the nickel and tin layer electroplating step S6: the nickel layer 6 and the tin layer 7 are sequentially plated on the copper layer 5 electroplated in the above S5 by the same electroplating method, that is, the preparation process of the one-piece molded inductor with the top covered conductor is completed, wherein: the electroplating thickness of the nickel layer 6 is set to 1μm~10μm, within this range, the copper layer 5 and the tin layer 6 can have better bonding; the electroplating thickness of the tin layer 7 is set to 1μm~10μm, within this range, the inductor can have better solderability.

[0052] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An integrally molded inductor structure with a top-covered conductor, characterized in that: The invention comprises a die-cast inductor body (1), wherein an enameled wire coil (2) is wound at the central position of the interior of the die-cast inductor body (1), and the end edges of both ends of the enameled wire coil (2) are exposed on the outer surface of the die-cast inductor body (1), and the outer surface of the die-cast inductor body (1) is provided with a copper layer (5), and the copper layer (5) is distributed in an external electrode setting area on the outer surface of the die-cast inductor body (1), and the external electrode setting area comprises a first external electrode setting area (4-A) and a second external electrode setting area, and the first external electrode setting area (4-A) is located at both ends of one side of the die-cast inductor body (1) and is used to respectively connect the internal enameled wire coil. (2), the second external electrode setting area is a rectangular area located between adjacent first external electrode setting areas (4-A) and not connected to the internal enameled wire coil (2), the second external electrode setting area includes a second external electrode main setting area (4-B1) and a second external electrode grounding setting area (4-B2) for grounding function, the second external electrode main setting area (4-B1) and the second external electrode grounding setting area (4-B2) are connected, the non-copper layer covering area of ​​the outer surface of the die-cast inductor body (1) is provided with an insulating varnish (3), and the outer surface of the copper layer (5) is provided with a nickel layer (6) and a tin layer (7) in sequence; The preparation process of the above-mentioned integrally formed molded inductor structure with a top-covered conductor comprises the following steps: Material preparation step S1: preparing a die-cast inductor body (1) to be processed, wherein the die-cast inductor body (1) is formed by die-casting magnetic powder, a circular enameled wire coil (2) is wound around the center of the die-cast inductor body (1), and the end edges of both ends of the enameled wire coil (2) are exposed on the outer surface of the die-cast inductor body (1); Insulating varnish coating step S2: coating a layer of insulating varnish (3) on the outer surface of the die-cast inductor body (1) obtained in S1 above; Laser engraving the outer electrode area step S3: using a laser source to remove the insulating paint (3) in the outer electrode setting area, thereby exposing the molded inductor in the outer electrode setting area; Grinding and removing step S4: using a grinding device to further remove the side surfaces of the die-cast inductor corresponding to the two end edges of the enameled wire in the die-cast inductor obtained in S3, thereby further exposing the two end edges of the enameled wire coil (2); Electroplating copper layer step S5: electroplating a copper layer (5) on the outer electrode setting area in the above S3 and the grinding and removal area in the above S4; Electroplating nickel and tin layer step S6: Similarly, a nickel layer (6) and a tin layer (7) are plated in sequence on the copper layer (5) electroplated in the above S5 by electroplating, thereby completing the preparation process of the integrally formed molded inductor with the top covered conductor.

2. The one-piece molded inductor structure with a top-covered conductor according to claim 1, characterized in that: The molded inductor body (1) in the material preparation step S1 is formed by die-casting soft magnetic powder with a particle size of 1-100 um mixed with organic resin.

3. The one-piece molded inductor structure with a top-covered conductor according to claim 2, characterized in that: The soft magnetic powder is any one of reduced iron powder, atomized iron powder, iron-nickel powder, iron-silicon-aluminum powder, iron-silicon-chromium powder or iron-silicon powder.

4. The one-piece molded inductor structure with a top-covered conductor according to claim 3, characterized in that: The content of the organic resin is 0.5% to 10%.

5. The one-piece molded inductor structure with a top-covered conductor according to claim 1, characterized in that: The insulating varnish (3) in the insulating varnish coating step S2 is any one of epoxy resin, acrylic resin, phenolic resin and silicone resin.

6. The one-piece molded inductor structure with a top-covered conductor according to claim 5, characterized in that: The insulating paint spraying method in the insulating paint coating step S2 is any one of roller spraying, normal pressure impregnation, vacuum impregnation, and high pressure impregnation.

7. The one-piece molded inductor structure with a top-covered conductor according to claim 1, characterized in that: In the grinding and removing step S4, the side surfaces of the die-cast inductor body corresponding to the end edges of the enameled wire coil are removed to a thickness of 0.01 mm to 0.1 mm.

8. The one-piece molded inductor structure with a top-covered conductor according to claim 1, characterized in that: The electroplating thickness of the copper layer (5) in the copper layer electroplating step S5 is 1 μm to 10 μm.

9. The one-piece molded inductor structure with a top-covered conductor according to claim 1, characterized in that: In the step S6 of electroplating the nickel and tin layers, the electroplated thickness of the nickel layer (6) is 1 μm to 10 μm, and the electroplated thickness of the tin layer (7) is 1 μm to 10 μm.

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