A lead frame, a vertical coupled inductor using the lead frame, and an inductor processing method

Abstract

The present invention discloses a lead frame and a vertical coupled inductor and an inductor processing method using the lead frame. The processed vertical coupled inductor is integrally formed and includes an inductor magnet and at least one group of inductor conductors buried inside the inductor magnet. Each group of inductor conductors includes two independently arranged coupling wires. The multiple coupling wires are arranged in parallel and the planes where they are located are perpendicular to the upper end surface of the inductor magnet. Both ends of the coupling wires are higher than the upper end surface of the inductor magnet. The lead frame of the present invention has a simple structure and excellent use effect. The coupled inductor processed by the lead frame is a vertical, integrally formed structure. The production process is simple and can realize automated production. The inductor as a whole has many advantages such as high frequency, no noise, ultra-large current, and high insulation.

Description

Technical Field

[0001] The present invention relates to a processing technology related to a coupled inductor, in particular to a lead frame and a vertical coupled inductor using the lead frame and an inductor processing method, belonging to the technical field of inductor processing. Background Art

[0002] Inductor is the most common component in electronic equipment and is also one of the important components in circuits. It is widely used in various circuits to achieve the functions of filtering, energy storage, matching, and resonance.

[0003] Generally speaking, most common inductors are modular structures, consisting of three parts: a coil, a core column, and a shell. During the assembly process of this type of inductor, the coil needs to be put on the core column first, and then the core column is placed in the shell. The various parts are then combined together by welding or bonding to finally complete the assembly of the inductor.

[0004] With the continuous development of computer communication technology in recent years, various hardware devices are being updated and iterated more and more frequently. Taking the manufacturing and processing of server machines as an example, the requirements for power inductors used in them are becoming more and more stringent, including high frequency, low DCR (direct current resistance), high current, low EMI (electromagnetic interference), high reliability, etc. Under such requirements, the defects of existing inductors are gradually emerging.

[0005] First, most of the power inductor devices in the prior art are horizontal structures, which occupy too much space. Under the development trend of miniaturization and intensification of electronic devices, the excessive volume and high space occupancy rate seriously restrict the overall layout of the circuit and affect the simplified design of the circuit.

[0006] Secondly, since the existing inductor devices are modular in design and have a relatively complex overall structure, during the processing, the spot welding of the internal coil of the device is prone to cold welding and leaking welding, which greatly increases the possibility of contact resistance, which not only reduces the reliability of the inductor device, but also increases the overall DC resistance of the device.

[0007] Thirdly, also due to the combined structure of existing inductor devices, when large current is passed through the inductor during actual use, jitter problems of internal components are very likely to occur in a high-frequency environment, thereby generating serious noise.

[0008] Due to the above-mentioned defects in the existing technology, several improved production processes for high-current power inductors have emerged. However, these processes still have many problems in the actual application stage, such as high manufacturing difficulty, high production cost, and inconvenience for automated production.

[0009] In summary, how to propose a new vertical coupled inductor and its corresponding production process based on various existing technologies, which can not only ensure the reliability of its application but also further simplify the production process of the device, has become an urgent problem to be solved by technicians in this field. Summary of the invention

[0010] In view of the above-mentioned defects in the prior art, the purpose of the present invention is to provide an integrally formed, high-reliability vertical coupled inductor and its related production process, which are specifically as follows.

[0011] A lead frame is used to replace the coil in an inductor device by equivalent means. The lead frame is integrally formed and comprises two sections of effective parts and two sections of connecting parts. The two sections of the effective parts are symmetrically arranged and the same sides of the two sections of the effective parts are connected by means of one section of the connecting part. The two sections of the connecting parts are arranged in parallel and the two sections of the connecting parts are in the same plane as a whole. The two sections of the effective parts are arranged in parallel and the planes where the two sections of the connecting parts are located are respectively perpendicular to the planes where the two sections of the connecting parts are located. The two sections of the effective parts and the two sections of the connecting parts together form a closed special-shaped ring structure. The cross-section of the lead frame is rectangular or circular.

[0012] Preferably, the utility portion and the connection portion are both in a U-shaped structure as a whole, and the turning position of the U-shaped structure has a smooth transition or a zigzag transition.

[0013] Preferably, the turning position of the U-shaped structure on the utility part has a zigzag transition, and each section of the utility part includes two vertical sections of the utility part and one horizontal section of the utility part, both ends of the horizontal section of the utility part are respectively connected to one end of one vertical section of the utility part, and the other end of each vertical section of the utility part is respectively connected to one end of one of the connecting parts.

[0014] Preferably, the lead frame is a copper sheet lead frame, and the cross-sectional shape of the lead frame is rectangular.

[0015] A vertical coupled inductor is made using the lead frame as described above, comprising an inductor magnet and at least one group of inductor conductors buried inside the inductor magnet, the inductor magnet and the inductor conductor are integrally formed, each group of the inductor conductors comprises two independently arranged coupling wires, a plurality of the coupling wires are arranged in parallel and the planes where they are located are perpendicular to the upper end surface of the inductor magnet, both ends of the coupling wires are higher than the upper end surface of the inductor magnet; the equivalent number of turns of each of the coupling wires is less than 1, and the relative magnetic permeability of the inductor magnet is 10-120.

[0016] Preferably, the inductor magnet is formed by a die-cast combination of insulating powder, adhesive, lubricant and curing agent; the insulating powder includes any one or more combinations of iron powder, iron silicon powder, iron silicon chromium powder, iron silicon aluminum powder and amorphous powder; the adhesive includes any one or more combinations of epoxy resin, silicone resin, phenolic resin, polyimide, polyphenylene sulfide and melamine resin; the lubricant includes any one or more combinations of stearic acid, aluminum stearate, magnesium stearate, calcium stearate and zinc stearate.

[0017] Preferably, each of the coupling wires includes a utility portion and connecting pins connected to both ends of the utility portion, the utility portion is generally U-shaped, and the turning position of the U-shaped structure is tortuous, each of the utility portion includes two utility portion vertical segments and one utility portion horizontal segment, the two ends of the utility portion horizontal segment are respectively connected to one end of a segment of the utility portion vertical segment, and the other end of each segment of the utility portion vertical segment is respectively connected to a connecting pin, and the upper end portion of each of the connecting pins is higher than the upper end surface of the inductor magnet.

[0018] Preferably, the equivalent number of turns of each of the coupling wires is 3 / 4, and the relative magnetic permeability of the inductive magnet is 30.

[0019] An inductor processing method, using the lead frame as described above, is used to process the vertical coupled inductor as described above, comprising the following steps:

[0020] S1. Mixing insulating powder, adhesive, lubricant and curing agent in proportion to obtain magnetic powder for pressing;

[0021] S2, setting a processing mold made of metal or plastic material, placing at least one lead frame in the processing mold, injecting the preheated pressing magnetic powder into the processing mold, so that the effective part of the lead frame is completely buried in the pressing magnetic powder, and the side and upper end surface of the connecting part of the lead frame protrude from the pressing magnetic powder, then pressing and processing so that the lead frame and the pressing magnetic powder become one, and then demolding, to obtain an inductor processing intermediate piece;

[0022] S3, performing heat treatment on the inductor processing intermediate piece to obtain an inductor semi-finished product;

[0023] S4, cutting off the lateral parts of the connecting part and the two sides of the semi-finished inductor, so that each of the lead frames is broken to form two coupling wires independently buried inside the inductor magnet, and both ends of the coupling wires are higher than the upper end surface of the inductor magnet, and finally a vertical coupled inductor finished product is obtained.

[0024] In S2, the preheating temperature of the magnetic powder for pressing is 50°C to 100°C, the preheating time is 1 min to 3 min, the pressing process is cold pressing or hot pressing, and during pressing, the pressure is maintained at 600 MPa to 2000 MPa for 30 s to 60 s;

[0025] In S3, the heat treatment process is performed at a temperature of 80°C to 1000°C and for a duration of 30 minutes to 360 minutes.

[0026] Compared with the prior art, the advantages of the present invention are mainly reflected in the following aspects:

[0027] The lead frame used in the present invention can be obtained by simple metal die-casting, and the processing process is fast, the processing difficulty is low, and it is suitable for large-scale applications. Moreover, in the coupled inductor of the present invention, by using the lead frame to replace the traditional coil, the wire structure inside the magnet is simplified, the wire setting is extremely streamlined, the maximum current that the inductor can withstand is increased, its insulation performance is guaranteed, and the stability of the use of the inductor is improved.

[0028] At the same time, the coupled inductor in the present invention adopts a vertical structure, which is different from the horizontal structure in the prior art, reducing the overall volume and space occupied by the device, so that its setting flexibility in various circuit structures is guaranteed. Moreover, in the coupled inductor of the present invention, at least one group of coupled wires and multiple connecting pins are provided, which further improves the setting flexibility of the inductor device. The user can choose to connect the coupled wires in series, in parallel or in multiple groups to the corresponding circuit structure according to actual use needs, thereby maximizing the application scenarios of the present invention.

[0029] In addition, the inductor processing method disclosed in the present invention is mature in technology and has low process difficulty. It only needs to cut off the excess parts after the device is integrally formed to complete the entire processing, which is suitable for automated production. Moreover, because the overall structure of the inductor of the present invention is integrally formed, there will be no noise problem caused by the jitter of the internal device during use, and the use effect is excellent.

[0030] Finally, the present invention also provides a reference for other related solutions in the same field, which can be expanded and extended to apply such structure to other technical solutions of inductor devices, and has a very broad application prospect.

[0031] The specific implementation modes of the present invention are further described below in combination with the accompanying drawings of the embodiments, so that the technical solutions of the present invention are easier to understand and grasp. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the lead frame in the present invention;

[0033] Figure 2 It is a schematic diagram of the structure of the semi-finished inductor of the present invention;

[0034] Figure 3 It is a structural schematic diagram of a finished product of a neutral coupled inductor of the present invention;

[0035] Among them: 1. Utility part; 11. Vertical section of utility part; 12. Horizontal section of utility part; 2. Connecting part; 21. Connecting pin; 3. Inductor magnet; 4. Coupling wire. DETAILED DESCRIPTION

[0036] The present invention proposes an integrally formed, high-reliability vertical coupled inductor and a related production process, which are specifically described as follows.

[0037] like Figure 1 As shown, a lead frame is used to equivalently replace the coil in the inductor device. The overall structure of the lead frame is integrally formed and consists of two sections of effective parts 1 and two sections of connecting parts 2. The two sections of the effective parts 1 are symmetrically arranged and the same sides of the two sections of the effective parts 1 are connected by means of one section of the connecting part 2.

[0038] The two sections of the connecting parts 2 are arranged in parallel and are located in the same plane as a whole. The two sections of the utility parts 1 are arranged in parallel and the planes where the two sections of the connecting parts 2 are located are respectively perpendicular to the planes where the two sections of the connecting parts 2 are located.

[0039] The two sections of the utility part 1 and the two sections of the connecting part 2 together form a closed special-shaped ring structure, and the cross-section of the wire rack is rectangular or circular, and correspondingly, the metal wire is a round wire or a flat wire. In this embodiment, the wire rack is a copper sheet wire rack, and the cross-section of the wire rack is rectangular.

[0040] The utility portion 1 and the connection portion 2 are similar in structure, and both are U-shaped structures as a whole. The turning position of the U-shaped structure can be a smooth transition or a tortuous transition.

[0041] In this embodiment, the turning position of the U-shaped structure on the utility part 1 has a zigzag transition, and each section of the utility part 1 includes two utility part vertical sections 11 and one utility part horizontal section 12, and the two ends of the utility part horizontal section 12 are respectively connected to one end of one section of the utility part vertical section 11, and the other end of each section of the utility part vertical section 11 is respectively connected to one end of one section of the connecting part 2.

[0042] The specific shape of the connecting portion 2 does not have much influence on the practical application of the present invention. In this solution, the turning position of the U-shaped structure on the connecting portion 2 is also tortuous. The preferred solution here is that at the connecting position of the connecting portion 2 and the utility portion 1, the section of the connecting portion 2 is parallel.

[0043] The lead frame used in the present invention can be obtained by simple metal die-casting, and the processing process is fast, the processing difficulty is low, and it is suitable for large-scale applications. Moreover, in the coupled inductor of the present invention, by using the lead frame to replace the traditional coil, the wire structure inside the magnet is simplified, the wire setting is extremely streamlined, the maximum current that the inductor can withstand is increased, its insulation performance is guaranteed, and the stability of the use of the inductor is improved.

[0044] like Figure 3 As shown, a vertical coupled inductor is made using the lead frame as described above, including an inductor magnet 3 and at least one group of inductor conductors buried inside the inductor magnet 3, and the inductor magnet 3 and the inductor conductor are integrally formed.

[0045] It should be noted that if multiple groups of the inductor conductors are provided, the multiple groups of the inductor conductors are provided in parallel and arranged in an array shape as a whole. In this embodiment, only one group of inductor conductors is provided inside the inductor magnet 3 .

[0046] Each group of the inductor conductors includes two independently arranged coupling wires 4, and the plurality of coupling wires 4 are arranged in parallel and the planes on which they are located are perpendicular to the upper end surface of the inductor magnet 3, and both ends of the coupling wires 4 are higher than the upper end surface of the inductor magnet 3. The structural setting higher than the end surface here is to ensure that the final vertical coupled inductor product can be better welded in the circuit. The structural setting here has a common standard in the industry and will not be repeated here.

[0047] In actual application, the coupling wires 4 inside the inductor can be connected in parallel, in series or in other ways required by the user. The coupling wires 4 in each group of the inductor conductors can be connected to the same circuit or to different circuits, and the overall connection method is diverse.

[0048] The equivalent number of turns of each coupling wire 4 is less than 1, and the relative magnetic permeability of the inductor magnet 3 is 10-120; in this embodiment, the equivalent number of turns of each coupling wire 4 is 3 / 4, and the relative magnetic permeability of the inductor magnet 3 is 30.

[0049] The inductor magnet 3 is formed by die-casting of insulating powder, adhesive, lubricant and curing agent. Specifically:

[0050] The insulating powder includes any one or more combinations of iron powder, iron silicon powder, iron silicon chromium powder, iron silicon aluminum powder and amorphous powder;

[0051] The adhesive includes any one or more combinations of epoxy resin, silicone resin, phenolic resin, polyimide, polyphenylene sulfide and melamine resin;

[0052] The lubricant includes any one or more combinations of stearic acid, aluminum stearate, magnesium stearate, calcium stearate and zinc stearate.

[0053] Since it is processed by the wire rack, each of the coupling wires also includes a utility portion 1 and connecting pins 21 connected to the two ends of the utility portion 1. The utility portion 1 is a U-shaped structure as a whole, and the turning position of the U-shaped structure is a tortuous transition. Each of the utility portions 1 includes two utility portion vertical segments 11 and one utility portion horizontal segment 12. The two ends of the utility portion horizontal segment 12 are respectively connected to one end of a utility portion vertical segment 11, and the other end of each utility portion vertical segment 11 is respectively connected to a connecting pin 21, and the upper end portion of each connecting pin 21 is higher than the upper end surface of the inductor magnet 3.

[0054] The coupled inductor in the present invention adopts a vertical structure, which is different from the horizontal structure in the prior art, reducing the overall volume and space occupied by the device, so that its setting flexibility in various circuit structures is guaranteed. Moreover, in the coupled inductor of the present invention, at least one group of coupling wires and multiple connecting pins are provided, which further improves the setting flexibility of the inductor device. The user can choose to connect the coupling wires in series, in parallel or in multiple groups to the corresponding circuit structure according to actual use needs, thereby maximizing the application scenarios of the present invention.

[0055] The present invention also discloses a method for processing an inductor, using the lead frame as described above to process the vertical coupled inductor as described above, comprising the following steps:

[0056] S1. Insulating powder, adhesive, lubricant and curing agent are mixed in proportion to obtain magnetic powder for pressing. The mixing ratio here can be further adjusted according to actual application and use needs. The specific ratios of various devices are different, which is not the focus of the present invention, so it will not be described in detail.

[0057] S2. Set up a processing mold made of metal or plastic material, place at least one lead frame in the processing mold, inject the preheated pressing magnetic powder into the processing mold, so that the effective part 1 on the lead frame is completely buried in the pressing magnetic powder, and the side and upper end surfaces of the connecting part 2 on the lead frame protrude from the pressing magnetic powder, then perform pressing processing to make the lead frame and the pressing magnetic powder become one, and then demold, to obtain an inductor processing intermediate piece.

[0058] In S2, the preheating temperature of the magnetic powder for pressing is 50°C~100°C, the preheating time is 1min~3min, the pressing process is cold pressing or hot pressing, and during pressing, the pressure is maintained at 600MPa~2000MPa for 30s~60s.

[0059] S3, heat treatment is performed on the inductor processing intermediate component, the heat treatment temperature is 80°C to 1000°C, the duration is 30min to 360min, and the following is obtained: Figure 2 The semi-finished inductor shown.

[0060] S4, cutting off the lateral parts of the connecting part 2 on both sides of the semi-finished inductor, so that each of the lead frames is broken to form two coupling wires 4 independently buried inside the inductor magnet 3, and both ends of the coupling wires 4 are higher than the upper end surface of the inductor magnet 3, and finally obtaining a vertical coupled inductor finished product.

[0061] The inductor processing method disclosed in the present invention is mature in technology and has low process difficulty. All processing can be completed by cutting off the excess parts after the device is integrally formed, which is suitable for automated production. Moreover, because the overall structure of the inductor of the present invention is integrally formed, there will be no noise problem caused by the jitter of the internal device during use, and the use effect is excellent.

[0062] Finally, the present invention also provides a reference for other related solutions in the same field, which can be expanded and extended to apply such structure to other technical solutions of inductor devices, and has a very broad application prospect.

[0063] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit and essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any reference numerals in the claims should not be regarded as limiting the claims involved.

[0064] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A lead frame used to replace the coil in an inductor device, characterized in that: The lead frame is integrally formed from a copper sheet, and the cross-sectional shape of the lead frame is rectangular. The lead frame comprises two sections of utility parts (1) and two sections of connecting parts (2) both of which are in a U-shaped structure. The turning position of the U-shaped structure has a smooth transition or a zigzag transition. The two sections of the utility parts (1) are symmetrically arranged and the same side of the two sections of the utility parts (1) is connected by means of a section of the connecting part (2). The two sections of the connecting part (2) are arranged in parallel and the two sections of the utility parts (1) are in the same plane as a whole. The two sections of the utility parts (1) are arranged in parallel and the planes where the two sections of the utility parts (1) are located are respectively perpendicular to the planes where the two sections of the connecting parts (2) are located. The two sections of the utility parts (1) and the two sections of the connecting parts (2) together form a closed special-shaped ring structure. When the inductor is in a semi-finished state, the lateral part of the connecting part (2) is cut off, so that the lead frame is broken to form two coupling wires (4) independently buried in the inductor magnet (3).

2. The lead frame according to claim 1, characterized in that: The turning position of the U-shaped structure on the utility part (1) is in a zigzag transition, and each section of the utility part (1) comprises two utility part vertical sections (11) and one utility part horizontal section (12), the two ends of the utility part horizontal section (12) are respectively connected to one end of one section of the utility part vertical section (11), and the other end of each section of the utility part vertical section (11) is respectively connected to one end of one section of the connecting part (2).

3. A vertical coupled inductor, made using the lead frame as claimed in any one of claims 1 to 2, characterized in that: The invention comprises an inductor magnet (3) and at least one group of inductor conductors buried inside the inductor magnet (3); the inductor magnet (3) and the inductor conductor are integrally formed; each group of the inductor conductors comprises two coupling wires (4) separated by a wire frame; a plurality of the coupling wires (4) are arranged in parallel and the planes on which they are located are perpendicular to the upper end surface of the inductor magnet (3); both ends of the coupling wires (4) are higher than the upper end surface of the inductor magnet (3); the equivalent number of turns of each coupling wire (4) is less than 1; and the relative magnetic permeability of the inductor magnet (3) is 10-120.

4. The vertical coupled inductor according to claim 3, characterized in that: The inductor magnet (3) is formed by die-casting a combination of insulating powder, adhesive, lubricant and curing agent; the insulating powder includes any one or more combinations of iron powder, iron silicon powder, iron silicon chromium powder, iron silicon aluminum powder and amorphous powder; the adhesive includes any one or more combinations of epoxy resin, silicone resin, phenolic resin, polyimide, polyphenylene sulfide and melamine resin; the lubricant includes any one or more combinations of stearic acid, aluminum stearate, magnesium stearate, calcium stearate and zinc stearate.

5. The vertical coupled inductor according to claim 3, characterized in that: Each of the coupling wires comprises a utility portion (1) and connecting pins (21) connected to two ends of the utility portion (1); the utility portion (1) is a U-shaped structure as a whole, and the turning position of the U-shaped structure is a tortuous transition; each of the utility portions (1) comprises two utility portion vertical sections (11) and one utility portion horizontal section (12); the two ends of the utility portion horizontal section (12) are respectively connected to one end of a utility portion vertical section (11); the other end of each utility portion vertical section (11) is respectively connected to a connecting pin (21); and the upper end of each connecting pin (21) is higher than the upper end surface of the inductor magnet (3).

6. The vertical coupled inductor according to claim 3, characterized in that: The equivalent number of turns of each coupling wire (4) is 3 / 4, and the relative magnetic permeability of the inductive magnet (3) is 30.

7. An inductor processing method, used for processing the vertical coupled inductor as claimed in any one of claims 3 to 6, characterized in that: The steps include: S1. Mixing insulating powder, adhesive, lubricant and curing agent in proportion to obtain magnetic powder for pressing; S2, setting a processing mold made of metal or plastic material, placing at least one lead frame in the processing mold, injecting the preheated pressing magnetic powder into the processing mold, so that the effective part (1) on the lead frame is completely buried in the pressing magnetic powder, and the side and upper end surface of the connecting part (2) on the lead frame protrude from the pressing magnetic powder, then performing pressing processing so that the lead frame and the pressing magnetic powder become one, and then demolding, to obtain an inductor processing intermediate piece; S3, performing heat treatment on the inductor processing intermediate piece to obtain an inductor semi-finished product; S4, cutting off the two sides of the semi-finished inductor and the lateral part of the connecting part (2), so that each of the lead frames is broken to form two coupling wires (4) independently buried inside the inductor magnet (3), and both ends of the coupling wires (4) are higher than the upper end surface of the inductor magnet (3), and finally obtaining a vertical coupled inductor finished product.

8. The induction processing method according to claim 7, characterized in that: In S2, the preheating temperature of the magnetic powder for pressing is 50°C to 100°C, the preheating time is 1 min to 3 min, the pressing process is cold pressing or hot pressing, and during pressing, the pressure is maintained at 600 MPa to 2000 MPa for 30 s to 60 s; In S3, the heat treatment process is performed at a temperature of 80°C to 1000°C and for a duration of 30 minutes to 360 minutes.

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