A surface-mount unshielded power inductor and its fabrication method

Abstract

The present invention discloses a chip-type non-shielded power inductor and a preparation method thereof, belonging to the field of inductor technology. A chip-type non-shielded power inductor comprises a magnetic core and a coil wound around the outer wall of the magnetic core, and further comprises: a split housing, the split housing being arranged at both ends of the magnetic core; a positioning component, the positioning component being arranged on one side of the split housing, and the positioning component being used to position the two ends of the coil; a protective component, the protective component being sleeved on one end of the coil, and the protective component being used to prevent the coil from being damaged; the present invention forms a non-shielded inductor with good welding resistance and heat resistance, suitable for ordinary welding and reflow soldering, and low cost; thereby enhancing the stability of the PIN pin assembly position structure, preventing material cracking, and the positioning block being able to move within the first end plate, thereby increasing the installation adaptation range of the PIN pin; for small-sized inductors, a guide sleeve is provided for guidance, facilitating the installation and connection of the ends of the coil.

Description

Technical Field

[0001] This invention relates to the field of inductor technology, and in particular to a surface-mount unshielded power inductor and its fabrication method. Background Technology

[0002] Surface mount power inductors are characterized by miniaturization, high quality, high energy storage, and low resistance. They are suitable for surface mounting and possess excellent end-face strength and good solderability. Furthermore, surface mount power inductors can withstand high currents and are available in tape and reel packaging for easy automated assembly. Generally, unshielded inductors have their enameled wires exposed on the outside without magnetic shielding; that is, unshielded inductors have an open magnetic circuit. An open magnetic circuit refers to an inductor with a significant air gap. They are typically small in size, easy to attach to surfaces, and suitable for fully automated production.

[0003] Existing inductors often have pins at the bottom for insertion during use. However, the pin mounting position on the base of current plug-in inductors is structurally weak, which can easily lead to material breakage during assembly, resulting in product scrap. Even if assembly is successful, it can pose a potential threat to the reliability of the product. This not only increases the inconvenience of use but also increases the cost.

[0004] Moreover, the coil size of the existing small-size, high-inductance surface-mount power inductors is already very close to the size of the finished inductor, which can easily lead to problems such as exposed coils and magnetic leakage, posing a threat to the reliability and safety of the inductor in subsequent use. In addition, this has greatly increased the manufacturing difficulty and cost of small-size inductors. Summary of the Invention

[0005] The purpose of this invention is to address the problem that in the prior art, the PIN pin assembly position of the plug-in inductor on the base is structurally weak, which can easily lead to material breakage during assembly, resulting in product scrap. Even if the assembly is successful, it can still pose a potential threat to the reliability of the product. This not only increases the inconvenience of use but also increases the cost. Therefore, this invention proposes a surface-mount unshielded power inductor and its preparation method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A surface-mount unshielded power inductor includes a magnetic core and a coil wound around the outer wall of the magnetic core, and further includes: a split housing disposed at both ends of the magnetic core; a positioning component disposed on one side of the split housing and used to position both ends of the coil; and a protective component sleeved on one end of the coil and used to prevent damage to the coil.

[0008] Preferably, the split-type housing includes a first end plate and a second end plate, both sides of which are symmetrically provided with through slots. The second end plate is fixedly connected to the top of the magnetic core, and the first end plate is detachably connected to the bottom of the magnetic core by screws. The first end plate has a groove for accommodating the screw head.

[0009] To better position and connect the ceramic tile and the magnetic core, a snap-fit ​​assembly is further provided on the bottom of the first end plate and the magnetic core. The snap-fit ​​assembly includes a limiting cap disposed on the surface of the first end plate, and a limiting groove matching the limiting cap is provided on the bottom of the magnetic core.

[0010] Preferably, a heat dissipation groove is formed on the surface of the magnetic core at the winding position of the coil. The heat dissipation groove is spiral-shaped, and the opening position of the heat dissipation groove is staggered with the winding position of the coil.

[0011] Preferably, the positioning component includes a positioning block, the positioning block and the second end plate are slidably connected, the bottom of the positioning block is symmetrically provided with an insert, the second end plate is provided with a sliding groove, and the insert and the sliding groove are slidably connected.

[0012] To make the two ends of the coil positioned on the same side for easy installation, both ends of the coil pass through the positioning block and extend to the outside of the positioning block, and both ends of the coil are connected to PIN pins, which are connected to the coil bending section.

[0013] Preferably, the protective component includes a guide sleeve fitted onto the surface of the coil, a guide wheel is provided inside the guide sleeve, and an annular groove matching the coil is opened in the guide wheel, with the coil passing through between two sets of guide wheels.

[0014] To reduce wear during the coil's passage through the guide sleeve, the guide sleeve is further configured as a hollow tube with an installation slot inside. A wheel axle is connected through the guide sleeve, and both ends of the wheel axle are rotatably connected to the installation slot.

[0015] Preferably, a telescopic assembly for removing the positioning blocks is provided between the two sets of positioning blocks. The telescopic assembly includes an ear seat, and a bidirectional internal threaded sleeve is rotatably connected inside the ear seat. A left-hand threaded rod and a right-hand threaded rod are symmetrically connected inside the bidirectional internal threaded sleeve.

[0016] A method for fabricating a surface-mount unshielded power inductor includes the following steps:

[0017] Step 1: Core preparation: The magnetic core of the central layer is prepared using spherical powder; the spherical powder is insulated, and the insulated spherical powder, binder and solvent are mixed to obtain a first slurry with suitable viscosity. The first slurry is injected into a casting machine for casting to obtain the magnetic core.

[0018] Step 2: Preparation of magnetic sheet: The first and second end plates of the outer layer are prepared using sheet-like iron-silicon-aluminum powder. The sheet-like iron-silicon-aluminum powder is insulated. The insulated sheet-like iron-silicon-aluminum powder, binder and solvent are mixed to obtain a second slurry with suitable viscosity.

[0019] Step 3: The second slurry is injected into the casting machine for casting and then hot-pressed to obtain the first end plate and the second end plate;

[0020] Step 4: Assemble the surface mount inductor: Wind the coil around the outside of the magnetic core to form a central layer, and stack magnetic sheets on both sides of the central layer to obtain the inductor structure;

[0021] Step 5: Perform hot pressing and laser cutting on the inductor structure to obtain the chip inductor.

[0022] Compared with the prior art, the present invention provides a surface-mount unshielded power inductor, which has the following advantages:

[0023] 1. This surface-mount unshielded power inductor forms an unshielded inductor by setting separate first and second end plates at both ends of the magnetic core. It has good solderability and heat resistance, is suitable for ordinary soldering and reflow soldering, and has a low cost.

[0024] 2. This surface mount unshielded power inductor enhances the stability of the PIN pin assembly structure by setting a positioning block in the second end plate, through which the coil end passes and is bent to set the pin, thus preventing material breakage.

[0025] 3. This surface mount unshielded power inductor, by setting inserts and slots respectively, allows the positioning block and one end of the coil to move to any position on the surface of the second end plate through sliding connection of the positioning block and the second end plate, thereby improving the applicability of surface mount inductor installation.

[0026] 4. A guide sleeve with guide wheels is provided on the outer wall of one end of the coil to protect the coil and prevent the coil from being exposed or leaking magnetic flux. In addition, for small-sized inductors, the guide sleeve is provided for guidance, which facilitates the installation and connection of the coil end.

[0027] The parts of this device not described herein are the same as or can be implemented using existing technologies. This invention forms an unshielded inductor with good solderability and heat resistance, suitable for ordinary soldering and reflow soldering, and has a low cost. It enhances the stability of the PIN pin assembly position structure, preventing material breakage, and the positioning block can move within the first end plate, improving the installation and adaptation range of the PIN pin. It protects the coil, preventing coil exposure and magnetic leakage. Furthermore, for small-sized inductors, a guide sleeve is provided for guidance, facilitating the installation and connection of the coil ends. Attached Figure Description

[0028] Figure 1 This is a three-dimensional structural diagram of a surface-mount unshielded power inductor proposed in this invention;

[0029] Figure 2 This is a partial cross-sectional view of a surface-mount unshielded power inductor proposed in this invention.

[0030] Figure 3 This invention proposes a surface-mount unshielded power inductor. Figure 2 Enlarged structural diagram of section A;

[0031] Figure 4 This is a side cross-sectional view of a surface-mount unshielded power inductor proposed in this invention.

[0032] Figure 5 This is a cross-sectional view of the protective component of a surface-mount unshielded power inductor proposed in this invention.

[0033] Figure 6 This is a schematic diagram of the three-dimensional structure of the magnetic core of a patch-type unshielded power inductor proposed in this invention;

[0034] Figure 7 This is a three-dimensional structural diagram of a surface-mount unshielded power inductor expansion assembly proposed in this invention.

[0035] In the diagram: 1. First end plate; 2. Second end plate; 3. Magnetic core; 4. Coil; 5. Positioning block; 6. Pin; 7. Through slot; 8. Screw; 9. Limiting cap; 10. Limiting groove; 11. Groove; 12. Insert block; 13. Slide groove; 14. Guide sleeve; 15. Mounting slot; 16. Guide wheel; 17. Axle; 18. Heat dissipation groove; 19. Ear seat; 20. Bidirectional internal threaded sleeve; 21. Left-hand threaded rod; 22. Right-hand threaded rod. Detailed Implementation

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0037] Example 1:

[0038] Reference Figures 1-7 A surface-mount unshielded power inductor includes a magnetic core 3 and a coil 4 wound around the outer wall of the magnetic core 3. A heat dissipation groove 18 is formed on the surface of the magnetic core 3 at the winding position of the coil 4. The heat dissipation groove 18 is spiral-shaped, and the positions of the heat dissipation groove 18 and the winding position of the coil 4 are staggered. It also includes a split-type housing, which is disposed at both ends of the magnetic core 3. The split-type housing includes a first end plate 1 and a second end plate 2, and through slots 7 are symmetrically formed on both sides of the first end plate 1 and the second end plate 2.

[0039] In this embodiment, a first end plate 1 and a second end plate 2 are respectively connected to the two ends of the magnetic core 3 to form an unshielded inductor, which has good solderability and heat resistance, is suitable for ordinary soldering and reflow soldering, and has a low cost.

[0040] It should be noted that the first end plate 1 and the second end plate 2 are symmetrically provided with through slots 7 on both sides, which makes the inductor have good heat dissipation.

[0041] The second end plate 2 is fixedly connected to the top of the magnetic core 3, and the first end plate 1 is detachably connected to the bottom of the magnetic core 3 by screws 8. The first end plate 1 has a groove 11 for accommodating the nail head of the screw 8.

[0042] In this embodiment, a detachable screw 8 is provided between the second end plate 2 and the magnetic core 3. In order to avoid the screw head protruding after connection and affecting the installation of the surface mount inductor, a groove 11 is provided in the first end plate 1 to solve the above problem.

[0043] The first end plate 1 and the bottom of the magnetic core 3 are provided with a snap-fit ​​assembly. The snap-fit ​​assembly includes a limiting cap 9 disposed on the surface of the first end plate 1, and a limiting groove 10 matching the limiting cap 9 is opened at the bottom of the magnetic core 3.

[0044] In this embodiment, a limiting cap 9 is provided on the surface of the first end plate 1, and a limiting groove 10 matching the limiting cap 9 is provided at the bottom of the magnetic core 3. When the first end plate 1 and the magnetic core 3 are connected, they can be snapped together and fixed, and then tightened by screws 8 to ensure the stability of the detachable connection structure of the first end plate 1 and the magnetic core 3, thereby ensuring the overall structural stability of the surface mount inductor.

[0045] The positioning component is located on one side of the split housing and is used to position the two ends of the coil 4. The positioning component includes a positioning block 5, which is slidably connected to the second end plate 2. The bottom of the positioning block 5 is symmetrically provided with an insert 12, and the second end plate 2 is provided with a sliding groove 13. The insert 12 and the sliding groove 13 are slidably connected.

[0046] In this embodiment, a positioning component is provided on the top of the second end plate 2, including a positioning block 5 and a slide groove 13 for limiting the sliding connection of the positioning block 5. Two sets of insert blocks 12 are symmetrically arranged at the bottom of the positioning block 5. The sliding connection structure of the insert blocks 12 and the slide groove 13 enables the positioning block 5 and one end of the coil 4 to move to any position on the upper surface of the second end plate 2, thereby improving the applicability of surface mount inductor mounting.

[0047] Both ends of the coil 4 pass through the positioning block 5 and extend to the outside of the positioning block 5, and both ends of the coil 4 are connected to PIN pins 6, which are connected to the bent section of the coil 4.

[0048] In this embodiment, one end of the coil 4 extends through the positioning block 5 to the outside of the positioning block 5, and a PIN pin 6 is provided at the bend, which enhances the stability of the assembly position structure of the PIN pin 6 and prevents material breakage. In addition, the positioning block 5 can move within the first end plate 1, which improves the installation and adaptation range of the PIN pin 6.

[0049] A protective component is fitted onto one end of the coil 4 to prevent damage to the coil 4. The protective component includes a guide sleeve 14 fitted onto the surface of the coil 4, a guide wheel 16 disposed inside the guide sleeve 14, and an annular groove matching the coil 4 is formed inside the guide wheel 16, with the coil 4 passing through between two sets of guide wheels 16.

[0050] Considering that the end of coil 4 near the first end plate 1 needs to be bent and extended into the positioning block 5 on the second end plate 2, the length of one end of coil 4 exposed to the outside is increased. Therefore, in this embodiment, a guide sleeve 14 with a guide wheel 16 is provided on the outer wall of one end of coil 4 to protect coil 4 and prevent coil 4 from being exposed and leaking magnetism. In addition, for small-sized inductors, the guide sleeve 14 is provided for guidance, which facilitates the installation and connection of the end of coil 4.

[0051] The guide sleeve 14 is a hollow tube with an installation slot 15 inside. A wheel axle 17 is connected through the guide sleeve 14, and both ends of the wheel axle 17 are rotatably connected to the installation slot 15.

[0052] In this embodiment, mounting slots 15 are symmetrically provided inside the guide sleeve 14. The axle 17 and guide wheel 16, which are rotatably connected inside the mounting slots 15, are rotatably connected. This reduces wear on the coil 4 as it passes through the guide sleeve 14 and guides the passage of the coil 4. After installation, this part of the coil 4 is protected.

[0053] A telescopic assembly for removing the positioning blocks 5 is provided between the two sets of positioning blocks 5. The telescopic assembly includes a lug 19, a bidirectional internal threaded sleeve 20 is rotatably connected inside the lug 19, and a left-hand threaded rod 21 and a right-hand threaded rod 22 are symmetrically connected inside the bidirectional internal threaded sleeve 20.

[0054] In this embodiment, due to the environment in which the inductor is used, some dust will accumulate at the sliding connection position of the positioning block 5 and the second end plate 2 after a period of use, which will cause obstruction during cleaning. In order to facilitate the disassembly of the positioning block 5, a telescopic component is provided. During disassembly, the ear seat 19 is inserted into the second end plate 2 for fixation. The bidirectional internal thread sleeve 20 inside the ear seat 19 is rotated. Utilizing the structural characteristics of left / right rotation in the same direction and reverse lateral movement, the left-hand threaded rod 21 and the right-hand threaded rod 22 extend to both sides, so that the positioning block 5 can be pushed out of the slide groove 13 for easy disassembly.

[0055] It should be noted that the telescopic assembly is not installed during the operation of the inductor. Therefore, the ear socket 19 and the second end plate 2 are designed as plug-in structures to facilitate the use of the telescopic assembly.

[0056] Example 2:

[0057] Reference Figures 1-7 Similar to Example 1, but based on Example 1, a method for fabricating a surface-mount unshielded power inductor is proposed, including the following steps:

[0058] Step 1: Mix the spherical powder after insulation treatment, binder and solvent, and use a casting machine to cast the first slurry obtained after mixing to obtain magnetic core 3, and process heat dissipation grooves 18 on the surface of magnetic core 3;

[0059] Step 2: After insulating the sheet iron-silicon-aluminum powder, add binder and solvent to mix and obtain the second slurry. It is also cast in a casting machine and hot-pressed to obtain the first end plate 1 and the second end plate 2. The groove 13 is processed in the first end plate 1 and the second end plate 2.

[0060] Step 3: After installing pins 6 at both ends of coil 4, wind it around the outside of magnetic core 3 to form the inductor center layer;

[0061] Step 4: Stack magnetic sheets on both sides of the central layer to obtain the inductor structure;

[0062] Step 5: Pass both ends of the coil 4 through the positioning block 5 respectively, and slide the positioning block 5 into the groove 13. At the same time, put the guide sleeve 14 on the longer end of the coil 4 for protection, and bend the pin 6 to a suitable angle for inductor installation to obtain the surface mount inductor.

[0063] This invention also discloses a method for fabricating a surface-mount unshielded power inductor, comprising the following steps:

[0064] Step 1: Preparation of magnetic core 3: The magnetic core 3 of the central layer is prepared by using spherical powder. The spherical powder is insulated. The insulated spherical powder, binder and solvent are mixed to obtain a first slurry with suitable viscosity. The first slurry is injected into a casting machine for casting to obtain magnetic core 3.

[0065] Step 2: Preparation of magnetic sheet: The first end plate 1 and the second end plate 2 of the outer layer are prepared using sheet-like iron-silicon-aluminum powder. The sheet-like iron-silicon-aluminum powder is insulated. The insulated sheet-like iron-silicon-aluminum powder, binder and solvent are mixed to obtain a second slurry with suitable viscosity.

[0066] Step 3: The second slurry is injected into the casting machine for casting and then hot-pressed to obtain the first end plate 1 and the second end plate 2.

[0067] Step 4: Assemble the surface mount inductor: Wind the coil 4 around the outside of the magnetic core 3 to form a central layer, and stack magnetic sheets on both sides of the central layer to obtain the inductor structure;

[0068] Step 5: Perform hot pressing and laser cutting on the inductor structure to obtain the chip inductor.

[0069] It should be noted that spherical powders include any one or a combination of at least two of the following: iron-silicon, iron-silicon-aluminum, iron-silicon-chromium, iron-nickel, or iron-nickel-molybdenum.

[0070] The particle size D50 of the spherical powder is preferably 2-30 μm;

[0071] The flake-shaped iron-silicon-aluminum powder is a soft magnetic alloy powder with high magnetic permeability, and the particle size D50 is preferably 50-70μm.

[0072] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A surface-mount unshielded power inductor, comprising a magnetic core (3) and a coil (4) wound on the outer wall of the magnetic core (3), characterized in that, Also includes: The split-type housing is disposed at both ends of the magnetic core (3); A positioning component is disposed on one side of the split housing and is used to position the two ends of the coil (4); The protective component is sleeved on one end of the coil (4) and is used to prevent the coil (4) from being damaged. The split shell includes a first end plate (1) and a second end plate (2). The first end plate (1) and the second end plate (2) are symmetrically provided with through slots (7) on both sides. The second end plate (2) is fixedly connected to the top of the magnetic core (3). The first end plate (1) is detachably connected to the bottom of the magnetic core (3) by screws (8). The first end plate (1) is provided with a groove (11) for accommodating the nail head of the screw (8). The surface of the magnetic core (3) is provided with a heat dissipation groove (18) at the winding position of the coil (4). The heat dissipation groove (18) is set in a spiral shape, and the opening position of the heat dissipation groove (18) and the winding position of the coil (4) are staggered. The positioning component includes a positioning block (5), which is slidably connected to a second end plate (2). A plug (12) is symmetrically arranged at the bottom of the positioning block (5), and a groove (13) is provided in the second end plate (2). The plug (12) and the groove (13) are slidably connected.

2. The surface-mount unshielded power inductor according to claim 1, characterized in that, The first end plate (1) and the magnetic core (3) are provided with a snap-fit ​​assembly at the bottom. The snap-fit ​​assembly includes a limiting cap (9) disposed on the surface of the first end plate (1). The bottom of the magnetic core (3) is provided with a limiting groove (10) that matches the limiting cap (9).

3. A surface-mount unshielded power inductor according to claim 2, characterized in that, Both ends of the coil (4) pass through the positioning block (5) and extend to the outside of the positioning block (5), and both ends of the coil (4) are connected to PIN pins (6), which are connected to the bent section of the coil (4).

4. A surface-mount unshielded power inductor according to claim 1, characterized in that, The protective assembly includes a guide sleeve (14) fitted onto the surface of the coil (4), a guide wheel (16) is provided inside the guide sleeve (14), and an annular groove matching the coil (4) is opened inside the guide wheel (16), and the coil (4) passes through the two sets of guide wheels (16).

5. A surface-mount unshielded power inductor according to claim 4, characterized in that, The guide sleeve (14) is a hollow tube with an installation slot (15) inside. A wheel axle (17) is connected through the guide sleeve (14) and the two ends of the wheel axle (17) are rotatably connected to the installation slot (15).

6. A surface-mount unshielded power inductor according to claim 3, characterized in that, A telescopic assembly for removing the positioning block (5) is provided between the two sets of positioning blocks (5). The telescopic assembly includes an ear seat (19), and a bidirectional internal thread sleeve (20) is rotatably connected inside the ear seat (19). A left-hand threaded rod (21) and a right-hand threaded rod (22) are symmetrically connected inside the bidirectional internal thread sleeve (20).

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