Integrally-formed surface-mounted power inductor with high sealing performance

Abstract

An integrally-formed patch type power inductor with high sealing performance comprises a protection body, a coil is arranged in the middle of the protection body, electrode plates are arranged at the two ends of the coil, and the electrode plates penetrate through the protection body and then are fixed to the surface layer of the protection body. The protection body comprises a T-core and a U-core, after a boss in the middle of the T-core is inserted into a gap in the center of the coil, the end of the T-core makes contact with the inner face of the U-core, and the inner side and the outer side of the coil are wrapped and fixed in an all-around mode. The protection body is located at the position where the electrode plate is arranged and is provided with a notch corresponding to the electrode plate, and the electrode plate penetrates through the protection body and then is attached and fixed in the notch of the protection body; after the T-core, the U-core, the coil and the electrode plate are assembled, the T-core and the U-core are formed through hot pressing. According to the power inductor disclosed by the invention, the protective body can play a good role in protecting the coil, so that the coil is completely coated without deformation and is not easy to generate cracks.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic components, and in particular to an integrated chip-type power inductor with high sealing performance. Background Art

[0002] The emergence of one-piece molded inductors is attributed to the development of computer motherboard technology and power supply technology: the CPU main frequency is getting higher and higher, so there are high requirements for stable power supply and filtering. One-piece molded inductors solve this problem. They can work for a long time under high current conditions and can provide stable power supply for the CPU. Of course, the main function of the inductor is filtering, and in this respect, one-piece molded inductors are not inferior. Good material properties and special design make the inductor structure more stable and the impedance lower, so it has higher efficiency.

[0003] The one-piece molded inductor includes a base and a winding body. The base is formed by burying the winding body in metal magnetic powder by die-casting. The SMD pins are the lead pins of the winding body directly formed on the surface of the base, which has higher inductance and smaller leakage inductance than traditional inductors. The inductor is designed with an SMD structure, which will not damage the inductor during use and can improve production efficiency. The fully enclosed structure of the one-piece molded inductor has a good magnetic shielding effect, which can effectively reduce electromagnetic interference and is used in industries with high reliability requirements such as automotive, military, medical, and aerospace.

[0004] At present, most one-piece molded inductors are first spot-welded to the coil to weld the inductor to the coil, then the coil is placed in a mold, and after filling the mold with powder, the powder is pressurized and cold-pressed to form a protective shell that wraps the coil. Since cold pressing requires a large pressure to solidify the powder in the mold, when the powder in the mold is pressurized, the coil in the middle of the powder is also subjected to a large pressure. When the enamel layer of the coil is under great pressure, the insulation layer of the coil is easily damaged by pressure. After the insulation layer is damaged, a short circuit will occur between the copper wires of the coil. Furthermore, during cold pressing, the powder material is directly pressed. The powder material is irregular small particles. After being filled into the mold, it cannot be evenly distributed in the mold. After cold pressing, gaps of varying sizes will be formed inside the product. This kind of gap is prone to cracking when the product undergoes high temperature reflow soldering in the later stage. Summary of the invention

[0005] In view of the above-mentioned technical problems, the present technical scheme provides a highly sealed one-piece molded chip power inductor. The protective body adopts prefabricated T-core and U-core. After the two are assembled, when the T-core and U-core are sealed and pressed together, only a small pressure needs to be applied for pressing to achieve the sealing molding of the T-core and U-core; at the same time, the boss on the T-core can buffer the pressure when the inductor is pressurized, thereby protecting the coil and preventing the coil from being pressurized; it can effectively avoid the situation where the insulation layer of the coil is damaged due to the large pressure, resulting in a short circuit of the coil; it can effectively solve the above-mentioned problems.

[0006] The present invention is achieved through the following technical solutions: A highly sealed one-piece chip-type power inductor comprises a protective body, a coil is arranged in the middle of the protective body, electrode sheets are arranged at both ends of the coil, and the electrode sheets penetrate the protective body and are fixed to the surface layer of the protective body; the protective body comprises a T-core and a U-core, and after the boss in the middle of the T-core is inserted into the gap in the center of the coil, the end portion contacts the inner surface of the U-core, and the inner and outer sides of the coil are wrapped and fixed in all directions; the protective body is located at the position where the electrode sheet runs, and is provided with a notch corresponding to the electrode sheet, and the electrode sheet penetrates the protective body and is fixed in the notch of the protective body; after the T-core, U-core, coil and electrode sheet are assembled, the T-core and U-core are formed by hot pressing.

[0007] Furthermore, the T-core and U-core are made of hot pressed powder by a cold pressing preforming process to form a T-shaped cover with a boss in the middle and a U-shaped cover with a groove in the middle. The interior of the preformed T-core and U-core is not completely solidified; the coil is sleeved on the boss of the T-shaped cover and installed in the groove of the U-shaped cover.

[0008] Furthermore, the shape of the boss in the middle of the T-core is consistent with the shape of the gap in the middle of the coil, and the size of the boss is less than or equal to the size of the gap.

[0009] Furthermore, the weight of the coil is less than or equal to the friction between the coil and the boss, and the optimal size is that the coil will not fall due to its own weight after being sleeved on the boss in the middle of the T-core.

[0010] Furthermore, the coil is made of round wire, and welding points are respectively arranged at both ends of the round wire, and the welding points are respectively fixed to the electrode sheets and conductively connected.

[0011] Furthermore, the coil is a single coil or a double coil; when the coil is a single coil, the electrode sheet is a narrow terminal or / and a wide terminal; when the coil is a double coil, the electrode sheet is a narrow terminal; the narrow terminal or / and the wide terminal are arranged at intervals.

[0012] Furthermore, the coil is made of a flat wire, both ends of the flat wire are bent to form electrode sheets, and the protective layer and the insulating layer of the flat wire are removed at the position where the electrode sheets are formed.

[0013] Furthermore, the electrode sheet passes through the protective body, is bent and fixed along the direction of the notch, and when the electrode sheet is fixed in the groove, the surface of the electrode sheet is flush with the surface of the protective body. Beneficial Effects

[0014] The highly sealed one-piece chip-type power inductor proposed by the present invention has the following beneficial effects compared with the prior art: The protective body of the present technical solution adopts T-core and U-core which are prefabricated in advance. After the two are assembled, when the T-core and U-core are sealed and pressed, only a small pressure needs to be applied for pressing to achieve the sealing and forming of the T-core and U-core; at the same time, the boss on the T-core can buffer the pressure when the coil is pressurized, thereby protecting the coil and preventing the coil from being pressurized; it can effectively avoid the situation where the insulation layer of the coil is damaged due to high voltage, resulting in a short circuit of the coil; at the same time, the T-core and U-core of the protective body are formed by hot pressing. During hot pressing, the blanks of the T-core and U-core can be softened to form a reflowed paste. Only low pressure needs to be applied to the paste in the mold to squeeze the paste during the hot pressing process and fully combine with the coil without damaging the coil.

[0015] During the hot pressing molding process in the present technical solution, the protective body formed by the T-core and the U-core will be melted into a paste. During the application of low pressure, the paste is evenly distributed in the mold and has a higher density, so that the formed protective body completely covers the coil and has a higher strength, making it difficult for the protective body to deform or crack, which can effectively solve the problem of cracking of the protective shell.

[0016] During the prefabrication process of T-core and U-core in the technical solution, or during the subsequent hot pressing process, the powder density per unit volume of T-core and U-core can be denser than that during cold pressing, so that the material utilization rate of T-core and U-core is improved, and the performance of the protective body is more stable and the initial magnetic permeability is high. When the initial magnetic permeability of the protective body becomes higher, the inductor with the same inductance value can use a coil made of shorter copper wire, which can increase the space utilization rate inside the inductor. When the internal space of the magnetic material becomes larger, the wire diameter can be thicker, so that the resistance DCR is lower, the saturation current is higher, and the unit product volume is smaller. Relatively speaking, in the case of the same powder material, an inductor with a higher inductance value can be produced. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of Example 1 of the present invention.

[0018] Figure 2 for Figure 1 sectional view of .

[0019] Figure 3 for Figure 2 Front view of .

[0020] Figure 4 Schematic diagram of the structure of T-core in Example 1 of the present invention.

[0021] Figure 5 Schematic diagram of the structure of U-core in Example 1 of the present invention.

[0022] Figure 6 Schematic diagram of the structure of the coil in Example 1 of the present invention.

[0023] Figure 7 Schematic diagram of the structure of the electrode sheet in Example 1 of the present invention.

[0024] Figure 8 It is a schematic diagram of the overall structure of Example 2 of the present invention.

[0025] Fig. 9 Schematic diagram of the structure of the coil in Example 2 of the present invention.

[0026] Fig.10 Schematic diagram of the structure of the electrode sheet in Example 2 of the present invention.

[0027] Fig.11 It is a schematic diagram of the overall structure of Example 3 of the present invention.

[0028] Fig.12 for Fig.11 sectional view of .

[0029] Fig.13 for Fig.12 Front view of .

[0030] Fig.14 Schematic diagram of the structure of the coil in Example 3 of the present invention.

[0031] The markings in the accompanying drawings are: 1-protective body, 11-T-core, 12-U-core, 13-groove, 2-coil, 21-welding point, 3-electrode sheet. DETAILED DESCRIPTION

[0032] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Under the premise of not departing from the design concept of the present invention, various modifications and improvements made by ordinary persons in the art to the technical solutions of the present invention should all fall within the protection scope of the present invention. Example 1

[0033] like Figures 1 to 7 As shown, the one-piece molded chip power inductor includes a protective body 1, which includes a T-core 11 and a U-core 12. The T-core 11 adopts a T-shaped cover with a boss in the middle, and the U-core 12 adopts a U-shaped cover with a groove in the middle.

[0034] A coil 2 is provided in the middle of the protective body 1. The shape of the boss in the middle of the T-core 11 is consistent with the shape of the gap in the middle of the coil 2, and the size of the boss is less than or equal to the size of the gap. In this embodiment, the coil 2 is a circular coil, and the boss in the middle of the T-core 11 is a circular boss corresponding to the shape of the gap in the middle of the coil 2. (In addition to being circular, the coil can also be square, oval, etc.). The size of the boss is slightly smaller than the size of the coil 2, and the gravity of the coil 2 is less than or equal to the friction between the coil 2 and the boss. The optimal size is that the coil 2 will not fall due to its own gravity after being put on the boss in the middle of the T-core 11.

[0035] The coil 2 is sleeved on the boss of the T-shaped cover. After the boss in the middle of the T-core 11 is inserted into the gap in the center of the coil 2, the end contacts the inner surface of the U-core 12, and the coil 2 is fixedly installed in the groove of the U-shaped cover; so that the protective body 1 wraps the inner and outer sides of the coil 2 in all directions.

[0036] T-core and U-core are made of hot pressed powder through a cold pressing pre-forming process to form a T-shaped cover with a boss in the middle and a U-shaped cover with a groove in the middle. The surface of the pre-formed T-core and U-core has been formed, but the inside is not completely solidified and is powdery. During the hot pressing process, the solidified surface and internal powder of the T-core and U-core are melted together into a paste in the mold. In the process of applying low pressure to the mold, the paste is evenly distributed in the mold, so that the protective body after forming completely covers the coil, and the protective shell formed again later has higher density and greater strength.

[0037] Electrode sheets 3 are provided at both ends of the coil 2. The coil 2 is made of round wire and is a single coil. Welding points 21 are provided at both ends of the round wire, and the two welding points 21 are respectively fixed to the electrode sheets 3 and are conductively connected. In this embodiment, since the coil 2 is a single coil, the coil 2 has only two welding points 21 that are led out and welded to the electrode sheets 3. The electrode sheets 3 can use narrow wiring terminals or / and wide wiring terminals according to needs.

[0038] After the electrode sheet 3 passes through the protective body 1, it is fixed on the surface of the protective body 1; the protective body 1 is located at a position where the direction of the electrode sheet 3 is set, and is provided with a notch 13 corresponding to the size and shape of the electrode sheet 3. The electrode sheet 3 passes through the protective body 1, is bent and fixed along the direction of the notch 13, and is fitted and fixed in the notch 13 of the protective body 1; when the electrode sheet 3 is fixed in the notch 13, the surface of the electrode sheet 3 is flush with the surface of the protective body 1.

[0039] An insulating layer is also provided on the outer layer of the protective body 1 except for the electrode sheet 3. An electroplating layer is provided at the welding position of the electrode sheet 3. Example 2

[0040] like Figures 8 to 10 As shown, in addition to the single coil of round wire used in the embodiment 1, the coil 2 can also be a double coil of round wire. When the coil 2 is a double coil of round wire, the electrode sheet 3 uses a narrow terminal; the narrow terminal or / and the wide terminal are arranged at intervals.

[0041] The other structures in this embodiment, as well as the positional relationship and connection relationship between the structures are the same as those in Embodiment 1, and will not be repeated here. Example 3

[0042] like Figures 11 to 14 As shown, in addition to the round wire used in the coil 2 in the embodiment 1 and the embodiment 2, the present solution can also be a single coil or a double coil of a flat wire. When the coil 2 is a flat wire coil, electrode sheets can be welded to both ends of the flat wire, or the ends of the flat wire can be directly bent to form electrode sheets, and the protective layer and the insulating layer of the flat wire are removed at the position where the electrode sheet is formed, and an electroplating layer is provided.

[0043] The other structures in this embodiment, as well as the positional relationship and connection relationship between the structures are the same as those in Embodiment 1, and will not be repeated here.

Claims

1. A highly sealed one-piece chip power inductor, comprising a protective body, a coil is provided in the middle of the protective body, and electrode sheets are provided at both ends of the coil. The electrode sheets penetrate the protective body and are fixed to the surface layer of the protective body; the characteristics are: The protective body includes a T-core and a U-core. After the boss in the middle of the T-core is inserted into the gap in the center of the coil, the end portion contacts the inner surface of the U-core, wrapping and fixing the inner and outer sides of the coil in all directions; the protective body is located at the position where the electrode sheet runs, and is provided with a notch corresponding to the electrode sheet. After the electrode sheet passes through the protective body, it is fit and fixed in the notch of the protective body; after the T-core, U-core, coil and electrode sheet are assembled, the T-core and U-core are formed by hot pressing.

2. The highly sealed one-piece chip-type power inductor according to claim 1, characterized in that: The T-core and U-core are made of hot pressed powder through a cold pressing preforming process to form a T-shaped cover with a boss in the middle and a U-shaped cover with a groove in the middle. The interior of the preformed T-core and U-core is not completely solidified; the coil is sleeved on the boss of the T-shaped cover and installed in the groove of the U-shaped cover.

3. The highly sealed one-piece chip-type power inductor according to claim 2, characterized in that: The shape of the boss in the middle of the T-core is consistent with the shape of the gap in the middle of the coil, and the size of the boss is less than or equal to the size of the gap.

4. The highly sealed one-piece chip-type power inductor according to claim 3, characterized in that: The weight of the coil is less than or equal to the friction between the coil and the boss, and the optimal size is that the coil will not fall due to its own weight after being put on the boss in the middle of the T-core.

5. The highly sealed one-piece molded chip power inductor according to claim 1, characterized in that: The coil is made of round wire, and welding points are respectively arranged at both ends of the round wire, and the welding points are respectively fixed to the electrode sheets and are conductively connected.

6. The highly sealed one-piece chip-type power inductor according to claim 5, characterized in that: The coil is a single coil or a double coil; when the coil is a single coil, the electrode sheet is a narrow terminal or / and a wide terminal; when the coil is a double coil, the electrode sheet is a narrow terminal; the narrow terminal or / and the wide terminal are arranged at intervals.

7. The highly sealed one-piece chip-type power inductor according to claim 1, characterized in that: The coil is made of a flat wire, and the two ends of the flat wire are bent to form electrode sheets, and the protective layer and the insulating layer of the flat wire are removed at the position where the electrode sheets are formed.

8. A highly sealed one-piece molded chip power inductor according to claim 1 or 5 or 6 or 7, characterized in that: The electrode sheet (3) passes through the protective body (1), is bent and fixed along the direction of the notch (13), and when the electrode sheet (3) is fixed in the notch (13), the surface layer of the electrode sheet (3) is flush with the surface layer of the protective body (1).

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