TW201517083A - Magnetic core, chip inductor having magnetic core, and manufacturing method thereof - Google Patents

Abstract

The manufacturing method of a chip inductor having a magnetic core includes the following steps: (a) injecting both of a non-conductive ferromagnetic substance and a volatile solvent to a mold with multiple magnetic core cavities, so as to form a plurality of magnetic core prototypes; (b) performing mold release after the magnetic core prototypes are condensed in the magnetic core cavities; (c) heating to a temperature higher than a vaporization temperature of the volatile solvent, so as to vaporize the volatile solvent in the magnetic core prototypes and form a plurality of magnetic cores, wherein each magnetic core is formed with a recessed winding portion; and (d) winding a plurality of coils onto the recessed winding portions of the magnetic cores. According to the method, a small-size high-manufacturing-yield chip inductor having a magnetic core can be produced.

Description

Magnetic core, magnetic core chip inductor and manufacturing method thereof

The present invention relates to a magnetic core, a magnetic core chip inductor, and a method of fabricating the same.

As a self-inductive electronic component, the inductor has various functions such as filtering, suppressing transient current, alternating current, etc., reducing EMI noise and power conversion; therefore, it is widely used in electronic circuits such as oscillation, tuning, coupling, and filtering. , delay and deflection in circuits. It is usually manufactured by winding a coil on a core. When current flows through the coil, according to Faraday's law of electromagnetic induction, the coil will generate an electromotive force to counter this change, the so-called hysteresis.

The structure of the inductor includes a coil and a core. When the coil is energized, a magnetic line is formed. The magnetic line is diverged outward from the end of the core, and is returned to the other end of the core via the air to form a closed magnetic line loop, but the magnetic resistance of the air is larger. , resulting in poor magnetic permeability of the inductor as a whole. To improve the magnetic permeability, you can try to make the core form a loop, and keep the magnetic lines in the core to reduce the magnetic resistance and increase the inductance.

However, since the iron core is also a good conductor of electricity, if the coil wound around the iron core is broken, the copper wire is separated from the coating of the insulating paint, and the short circuit is short-circuited and guided to the iron core; and the polymer material without paramagnetic material is used. Covering the insulation will greatly reduce the magnetic induction. Therefore, the industry has proposed to replace the original iron core with a magnetic but non-conductive ceramic substrate such as ferric oxide. However, the material of ferric oxide is usually composed of powder particles pressed or sintered to form a substrate, and the materials are very brittle and easily broken.

If the turning process is used in the production process, it is difficult to carry out the fine part modification, and the shape of the processing is limited to a circular shape; therefore, the volume of the finished product is not easily reduced, the shape is limited, and the processing speed is limited, and the productivity cannot be improved. If the grinding method is used, the grinding machine will not be efficient and cannot be mass produced. Finally, whether it is a lathe or grinding, it will cause friction with the processed items and cause a certain amount of vibration. If the processed article is the aforementioned ferric oxide material, such a process may easily cause breakage of the ferric oxide material.

If the substrate is severely broken, it is unbearable. Even if it is only a slight crack, it will form an air gap between the magnetic conductive materials, which will greatly increase the magnetic resistance, so that the predetermined magnetic permeability is greatly reduced and becomes inferior, and the product yield is low, which will make The above processing slow problem has become more serious.

From the situation described above, it can be seen that the manufacturing method of the past inductor core can not greatly reduce the volume of the core, and does not conform to the trend of miniaturization of electronic components; the shape of the core is limited and there is no choice of elasticity, limiting the application of the inductor Scope; In addition, due to the need to grind one by one, it is impossible to mass produce; at the same time, the vibration rate during turning and polishing causes the product yield to be unable to increase. Therefore, if a manufacturing method can be provided, different shapes can be selected to shape a magnetic core of a smaller volume, which can maximize the production amount and minimize the damage rate of the production; and can solve the shortcomings of the prior art.

An object of the present invention is to provide a magnetic core, a magnetic core chip inductor and a manufacturing method thereof, which can mass-produce a magnetic core and greatly improve output efficiency.

Another object of the present invention is to provide a magnetic core, a magnetic core chip inductor and a method of manufacturing the same, which provide a ferroferric oxide material to be formed in a stable environment, which greatly reduces the damage rate of the forming process and improves the production yield.

A further object of the present invention is to provide a magnetic core, a magnetic core chip inductor and a system therefor The manufacturing method can shape a smaller volume of ferric oxide core and expand the application range of the non-conductive ferromagnetic core inductor.

Another object of the present invention is to provide a magnetic core, a magnetic core chip inductor and a manufacturing method thereof, which can shape a magnetic core such as an ellipse according to industrial requirements and magnetic field effects.

A method for manufacturing a magnetic core chip inductor, comprising the steps of: a) coextruding a non-conductive ferromagnetic substance together with a volatile solvent into a mold having a plurality of magnetic core cavities to form a plurality of magnetic core prototypes; b) after the magnetic core is condensed in the magnetic core cavity, and then demolded; c) heating to a vaporization temperature higher than the volatile solvent, so that the volatile solvent in the original shape of the magnetic core is vaporized to form a plurality of a magnetic core, and each of the magnetic cores is formed with a recessed winding portion; and d) a plurality of sets of coils are respectively wound around the recessed winding portions of the respective magnetic cores.

A magnetic core chip inductor comprising: a magnetic core comprising: a top portion formed with an adsorption plane; a base portion formed with a plurality of wire grooves and at least two bottom conductive electrodes; and a connecting the top portion and the base portion a recessed winding portion, wherein the recessed winding portion has a non-circular outer profile smaller than the top portion and the base portion; and a set of coils for winding to the recessed winding portion of the magnetic core, the two ends of the coil being parallel Each of the two wire grooves is respectively connected to the bottom conductive electrode; and a ferromagnetic colloid layer at least partially encloses the concave winding portion for magnetically connecting the top portion and the base portion.

The present invention seeks to provide a magnetic core, a magnetic core chip inductor and a method of manufacturing the same, which is formed by mixing a predetermined magnetic core material into, for example, a plastic material and injecting into a mold, and then heating to vaporize a low vaporization temperature such as a plastic material, magnetic The core is thus shaped. The magnetic core of the present invention comprises: a top portion; a base portion formed with a plurality of wire grooves and at least two bottom guiding electrodes; and a concave winding portion connecting the top portion and the base portion, and the concave winding portion has a smaller than the top portion With the outline of the base.

According to this method, a magnetic core mainly composed of, for example, ferric oxide can be simultaneously injected through a plurality of cavities during the manufacturing process, for example, a large number of magnetic core prototypes are formed at one time, and the original or multi-core magnetic core prototypes are simultaneously formed. Baking, vaporizing the mixed materials, allowing the manufacturing process to be formed in large quantities, greatly increasing output efficiency. In addition, the friction oscillation during turning or polishing is completely avoided during the processing, and the product yield is improved synchronously; in particular, the product shape is completely matched with the mold design, which can be more flexible, more flexible, and more compact in size, in line with miniaturization. trend. Even in the case of the present application, the applicant only used a mold having 64 cavities, but the person skilled in the art can naturally design the cavities to 128, 256 or more, which greatly increases the yield per batch.

2, 2'‧‧‧ magnetic core

21’‧‧‧ iron core

22‧‧‧ top

220‧‧‧Adsorption plane

23‧‧‧ base

230‧‧‧ wire trough

231‧‧‧Bottom conductive electrode

24, 24' ‧ ‧ sag winding department

4‧‧‧ coil

40‧‧‧ both ends

6‧‧‧ Ferromagnetic colloid layer

101, 102, 103, 104‧ ‧ steps

1 is a perspective view of a first embodiment of the present invention, illustrating the relationship between the main structures of the magnetic core, and the outer contour of the concave winding portion is smaller than the top and the base; FIG. 2 is a side view of the first embodiment of the present invention. FIG. 3 is a perspective view of the bottom surface of the first embodiment of the present invention, illustrating that the outer contour of the concave winding portion is smaller than the base portion and is non-circular elliptical; FIG. 4 is the first embodiment of the present invention. The side view of the embodiment illustrates the case where the coil is wound and the ferromagnetic colloid layer is attached; FIG. 5 is a plan view of the mold of the first embodiment of the present invention, illustrating the distribution of 64 cavities in the mold; FIG. The flow chart of the embodiment is a magnetic core and a manufacturing step of the magnetic core chip inductor; and FIG. 7 is a perspective view of the bottom surface of the second embodiment of the present invention, illustrating the core reinforcement in the magnetic core. The case of the magnetic permeability and the polygonal outline of the concave winding portion.

The magnetic core of the present invention, the magnetic core chip inductor and the manufacturing method thereof, the magnetic core of the first preferred embodiment of the present invention are as shown in FIG. 1 to FIG. 3, and the magnetic core 2 is a non-conductive ferromagnetic material for the release of ferric oxide. The material is constructed, side view such as I-shaped, and the basic structure includes a top portion 22, a base portion 23, and a recessed winding portion 24 connecting the top portion 22 and the base portion 23. As shown in the perspective view at the bottom of FIG. 3, the outer contour of the top portion 22 and the base portion 23 is larger than the outer contour of the concave winding portion 24 (the elliptical dotted line). The uppermost surface of the top 22 is an adsorption plane 220, which is convenient for the suction and movement of the nozzle of the mechanical arm when the surface of the inductor element is finally formed and mounted on the circuit board.

Referring to the side view 4 in which the coils are assembled, the lower surface of the base portion 23 forms a pair of bottom conductive electrodes 231, and the sides of the base portion 23 are formed with a pair of recessed grooves, defined herein as the wire grooves 230. a set of coils 4 are wound to the recessed winding portion 24 for conducting current to generate a magnetic field, and the two ends 40 of the coil 4 are respectively extended downward from the two wire slots 230 of the side edge of the base portion 23 to different guiding electrodes 231; Connect to the positive and negative pads on the board when installing.

The recessed winding portion 24, the portion of the top portion 22 and a portion of the base portion 23 are then covered with a layer of ferromagnetic colloid 6. Of course, as can be easily understood by those skilled in the art, the ferromagnetic colloid layer 6 herein can simply cover the recessed winding portion 24 and connect the top portion 22 and the base portion 23 to form a closed magnetic circuit. As in the structure of this example, the exposed portion above the top portion 22 is a flat adsorption plane 220, and the bottom conductive electrode 231 is exposed under the base portion 23, thereby forming a surface mountable chip inductive component. Among them, the ferromagnetic colloid layer 6 is made of a magnetic material mixed with rubber, so that the rubber contains a certain density of ferromagnetic metal powder, such as doped iron, cobalt, nickel and other paramagnetic metal powder, or oxidation of these metals Non-conductive ceramic powder such as a substance or nitride.

When the coil 4 is energized to generate a magnetic field, the magnetic core 2 is induced to increase the magnetic flux density, and the magnetic lines of force pass through the ferromagnetic colloid layer 6 outside the recessed winding portion 24, so that a smooth magnetic circuit is formed between the top portion 22 and the base portion 23, This greatly reduces the magnetic resistance in the road and further enhances the magnetic permeability.

The production method of the present invention will be described below. Please refer to the mold of FIG. 5 and the step flow of FIG. 6. In step 101, a non-conductive ferromagnetic material, such as ferric oxide in this example, is injected into a mold together with a volatile solvent. In this example, the mold is formed with 64 core mold holes of the same shape. It should be noted that the term "volatile solvent" as used herein does not mean an organic solvent which volatilizes at normal room temperature, but specifically refers to a material having a lower vaporization temperature than the above doped powder, for example, a vaporization temperature lower than that of the third oxidation. A molten polymer material such as iron; a mixed material of mixed ferric oxide powder and a volatile solvent is extruded, injected into a mold, and filled with 64 core mold holes to form 64 core prototypes. Further, in step 102, after the magnetic core is condensed in the core cavity, the mold is released, and the 64 core prototypes in which the non-conductive ferromagnetic substance is coagulated and mixed with the volatile solvent are taken out. The original shape of the magnetic core can be completely planned according to the precision of the current mold manufacturing, and the yield and precision are superior to the current technology.

Step 103 heats the 64 cores until the vaporization temperature of the volatile solvent is reached, so that the volatile solvent in the prototype of the core is completely vaporized, leaving a non-conductive ferromagnetic material to form a magnetic core having the foregoing structure. Finally, in step 104, 64 sets of coils are wound separately to the recessed winding portions of the 64 magnetic cores. Through the above steps, the core of the present invention and the magnetic core chip inductance can be completed. Since the injection molding is performed according to the embodiment, 64 or even more magnetic core prototypes can be produced in one batch, and multiple batches of magnetic materials can be used. The core is synchronously heated, and then automatically wound into an inductor; the purpose of mass production is achieved. And mold forming, providing a stable shaping environment to ensure iron oxide The production yield of fragile materials.

In addition, in this case, a mold and a cavity injection molding method are used to produce a more delicate magnetic core; and the application range of the ferroferric oxide core is expanded. It can solve the problem of the shape of the iron core which is not easily shaped in the past.

Referring to FIG. 7 in the second preferred embodiment of the present invention, it is considered that the magnetic permeability of the structure in which the iron oxide is mixed into the rubber is still less than that of iron. Therefore, in this embodiment, a perforation is formed in the middle of the magnetic core 2' for directly inserting a rod. The core 21' of the core 21' is surrounded by a non-conductive ferromagnetic core 2' to prevent electrical circulation and short circuit; and the inner and outer layers are designed to further enhance the magnetic permeability. In this example, the recessed winding portion 24' is also designed as a polygon in accordance with the situation. Those skilled in the art can also easily infer that the mold can contain more mold holes as long as it is properly arranged.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All should remain within the scope of the invention patent.

23‧‧‧ base

230‧‧‧ wire trough

231‧‧‧Bottom conductive electrode

24‧‧‧Sag winding department

Claims (9)

A method for manufacturing a magnetic core chip inductor, comprising the steps of: a) coextruding a non-conductive ferromagnetic substance together with a volatile solvent into a mold having a plurality of magnetic core cavities to form a plurality of magnetic core prototypes; b) after the magnetic core is condensed in the magnetic core cavity, and then demolded; c) heating to a vaporization temperature higher than the volatile solvent, so that the volatile solvent in the original shape of the magnetic core is vaporized to form a plurality of a magnetic core, and each of the magnetic cores is formed with a recessed winding portion; and d) a plurality of sets of coils are respectively wound around the recessed winding portions of the respective magnetic cores. The method for manufacturing a magnetic core chip inductor according to the first aspect of the invention, wherein the non-conductive ferromagnetic material is ferric oxide. The method for manufacturing a magnetic core chip inductor according to claim 1, wherein each of the magnetic cores includes a top portion and a base portion, and the top portion and the base portion are respectively coupled to the recessed winding portion, and each The top portion and the base portion have an outer shape larger than the recessed winding portion. The method for manufacturing a magnetic core chip inductor according to claim 3, wherein each of the base portions is formed with a plurality of wire grooves. The method of manufacturing a magnetic core chip inductor according to claim 3, wherein each of the base portions is formed with at least two bottom conductive electrodes. A magnetic core chip inductor comprising: a magnetic core comprising: a top portion formed with an adsorption plane; a base portion formed with a plurality of wire grooves and at least two bottom guiding electrodes; and a concave winding portion connecting the top portion and the base portion, and the concave winding portion has a non-circular shape smaller than the top portion and the base portion And a set of coils for winding to the recessed winding portion of the magnetic core, the two ends of the coil are respectively connected to the bottom conductive electrode via two of the wire grooves; and a ferromagnetic colloid layer, The recessed winding portion is at least partially encapsulated for magnetically connecting the top portion and the base portion. The magnetic core chip inductor according to claim 6, wherein the magnetic core is further formed with a through hole penetrating the top portion, the concave winding portion and the base portion, and the magnetic core further comprises an iron filling the through hole. core. The magnetic core chip inductor according to claim 6 or 7, wherein the outer circumference of the concave winding portion is elliptical. A magnetic core comprising: a top portion; a base portion formed with a plurality of wire grooves and at least two bottom conductive electrodes; and a concave winding portion connecting the top portion and the base portion, wherein the concave winding portion has a smaller than the top portion With the outline of the base.