CN112435843B

CN112435843B - Inductor manufacturing method and inductor

Info

Publication number: CN112435843B
Application number: CN202011373635.8A
Authority: CN
Inventors: 邱昭裕; 邓铭钦
Original assignee: Chilisin Electronics Corp
Current assignee: Chilisin Electronics Corp
Priority date: 2020-11-30
Filing date: 2020-11-30
Publication date: 2022-11-15
Anticipated expiration: 2040-11-30
Also published as: CN112435843A

Abstract

The invention discloses an inductor manufacturing method and an inductor. The inductor manufacturing method is used for manufacturing an inductor, the inductor comprises a packaging body, a coil and two pins, the coil is positioned in the packaging body, the two pins are connected with two ends of the coil, and one part of the two pins is exposed out of one bottom surface of the packaging body, and the inductor manufacturing method comprises the following steps: a preheating step: heating a core; a core body placing step: placing the heated core in a mold; a coil placing step: disposing a coil in a mold; powder filling step: filling a powder into the mold; a forming step: the mold is heated and pressurized to mold the powder into a package.

Description

Inductor manufacturing method and inductor

Technical Field

The present invention relates to a method for manufacturing an inductor and an inductor, and more particularly, to a method for manufacturing an inductor by a die casting method and an inductor manufactured by the method.

Background

Referring to fig. 1, a longitudinal section of a conventional inductor manufactured by die casting is shown, and it can be seen in the longitudinal section that a crack Z1 exists in the center of the inductor Z, and the crack Z1 directly or indirectly affects the characteristics of the inductor, such as magnetic permeability, inductance, and the like.

Disclosure of Invention

The invention discloses an inductor manufacturing method and an inductor, which are mainly used for solving the problems that cracks are often found in the longitudinal section of the inductor in the conventional inductor manufactured by a die casting mode.

One embodiment of the present invention discloses a method for manufacturing an inductor, which is used for manufacturing an inductor, the inductor includes a package, a coil and two pins, the coil is located in the package, the two pins are connected with two ends of the coil, and a part of the two pins is exposed out of a bottom surface of the package, the method for manufacturing an inductor includes: a preheating step: heating a core; a core body placing step: placing the heated core in a mold; a coil placement step: disposing a coil in a mold; a powder filling step: filling a powder into the mold; a forming step: the mold is heated and pressurized to mold the powder into a package.

Preferably, between the step of placing the core and the step of placing the coil, a step of pre-filling powder is further included: filling powder into the mould; the height of the powder filled in the step of pre-filling the powder is not less than one third of the height of the space in the die; in the powder filling step, the mold is filled with the powder.

Preferably, in the step of pre-filling powder, the temperature of the mold is a predetermined temperature, and a waiting step is further included between the step of pre-filling powder and the step of placing the coil: and waiting for at least a preset time to solidify at least one part of the powder in the mould.

Preferably, in the coil disposing step, a part of the coil is immersed in the powder in the mold.

Preferably, the predetermined temperature is between 100 and 180 degrees Celsius.

Preferably, the predetermined time is between 5 and 10 seconds.

Preferably, the preheating step is heating the core to 100-180 degrees celsius.

Preferably, the powder comprises the metal soft magnetic powder and an adhesive, the weight percentage concentration of the adhesive of the powder is 0.5wt% -10wt%, the core comprises the metal soft magnetic powder, and the density of the core is higher than that of the package.

Preferably, in the core body placing step, one end of the core body is connected with a positioning structure of a lower mold of the mold, and the core body is fixedly arranged on the lower mold through the positioning structure.

One embodiment of the present invention discloses an inductor, which is manufactured by using the inductor manufacturing method according to the present invention, wherein the bottom surface of the encapsulation of the inductor has a protruding structure, and the protruding structure is a part where the core and the positioning structure are connected with each other.

In summary, compared with the conventional inductor manufactured by die casting, the inductor manufactured by the method of the present invention has the advantage that the problems of cracks and the like are not easily generated in the longitudinal section of the inductor.

For a better understanding of the nature and technical content of the present invention, reference should be made to the following detailed description of the invention and the accompanying drawings, which are provided for illustration purposes only and are not intended to limit the scope of the invention in any way.

Drawings

Fig. 1 is a longitudinal section of an inductor manufactured by a conventional die casting method.

Fig. 2 is a schematic flow chart of a first embodiment of an inductor manufacturing method according to the present invention.

Fig. 3 is a schematic diagram of an inductor according to the present invention.

Fig. 4 is a schematic diagram of a longitudinal section of the inductor shown in fig. 3.

Fig. 5 is a schematic diagram of a lower mold and a core in the inductor manufacturing method of the present invention.

Fig. 6 is a flowchart illustrating a method for manufacturing an inductor according to a second embodiment of the present invention.

Fig. 7 is a schematic diagram of a middle mold and a lower mold of the inductor manufacturing method of the present invention.

Fig. 8 is a schematic cross-sectional view of a middle mold and a lower mold of the inductor manufacturing method of the present invention.

Fig. 9 to fig. 13 are schematic diagrams corresponding to partial steps of the inductor manufacturing method of the present invention, respectively.

Detailed Description

In the following description, reference is made to or is shown in the accompanying drawings for the purpose of illustrating the invention only, and not in any way limiting the scope of the invention.

Fig. 2 to 5 are also referred to, fig. 1 is a longitudinal section of a conventional inductor manufactured by die casting, fig. 2 is a schematic flow chart of a first embodiment of a method for manufacturing an inductor according to the present invention, fig. 3 is a schematic diagram of an inductor according to the present invention, fig. 4 is a schematic diagram of a longitudinal section of an inductor shown in fig. 3, and fig. 5 is a schematic diagram of a lower die and a core body of a method for manufacturing an inductor according to the present invention.

The inductor manufacturing method is used for manufacturing an inductor A, the inductor A comprises a packaging body A1, a coil A2 and two pins A3, the coil A2 is positioned in the packaging body A1, the two pins A3 are connected with two ends of the coil A2, one part of the two pins A3 is exposed out of a bottom surface A11 of the packaging body A1, and the inductor manufacturing method comprises the following steps:

a preheating step S1: heating a core;

a core placing step S2: placing the heated core body in a mould;

a coil disposing step S3: disposing coil A2 in a mold;

a powder filling step S4: filling a powder into the mold; and

a molding step S5: the mold is heated and pressurized to mold the powder into a package.

The core may be a cylindrical structure, but not limited thereto, and the core may also be a square column structure. The powder may include metal soft magnetic powder and adhesive. In a preferred embodiment, the weight percentage concentration of the adhesive of the powder may be between 0.5wt% and 10wt%, so as to ensure that the powder has better molding density and magnetic properties. The metal soft magnetic powder may be, for example, carbon-based iron powder, reduced iron powder, atomized iron powder, iron nickel powder, iron silicon aluminum powder, iron silicon chromium powder, iron silicon powder, etc., and the adhesive glue may be, for example, epoxy resin, acryl resin, phenol resin, silicon resin, etc. The powder may contain an additive such as a fatty acid such as stearic acid or graphite fluoride. In a specific application, the core may also contain soft magnetic metal powder, and the core and the powder may be substantially composed of the same material, and the density of the core is higher than that of the powder; after the preheating step S1, part of the adhesive in the core will escape, the hardness of the whole core will be relatively increased, and there will be a small gap in the core, so that the pressed core will not easily crack in the molding step S5.

In practical applications, in the pre-heating step S1, the core is heated to a first temperature, and in the molding step S5, the mold is heated to a second temperature, where the first temperature is not higher than the second temperature; for example, the first temperature may be between 100 and 180 degrees Celsius (C.) and the second temperature may be between 170 and 190 degrees Celsius (C.). In a specific implementation, the core may be heated by various methods, which are not limited herein, for example, the core may be disposed in an oven, and the core may be heated by hot air baking.

In the step S2, the heated core may be placed in the mold by using various devices such as a robot. In the core placing step S2, the "heated core" may be, for example, a core that has been heated and cooled to normal temperature, or may be a core that has not been cooled to normal temperature immediately after being heated, or may be a core that has been heated immediately after being cooled. Specifically, in the preferred embodiment, a cooling step may be further included between the preheating step S1 and the core placing step S2: and cooling the heated core body to the normal temperature.

As shown in fig. 5, in the core body placing step S2, one end of the core body A5 may be engaged with a positioning structure B21 of a lower mold B2 of the mold, so that the core body A5 is stably placed on the lower mold B2; for example, the core A5 may be a column structure, and the positioning structure B21 of the lower mold B2 may be a corresponding groove. Of course, in different embodiments, the positioning structure B21 of the lower mold B2 may also be a convex structure, and one end of the core may be a corresponding positioning structure with a concave shape.

It is particularly emphasized that, as long as the core A5 can be stably disposed in the lower mold B2, the shape and size of the positioning structure of the core A5 and the positioning structure B21 of the lower mold B2 can be changed according to the requirement, and are not limited to the embodiment shown in the drawings. In a preferred embodiment, in order to make it easier to dispose one end of the core A5 in the positioning structure B21 of the lower mold B2, one end of the core A5 may be chamfered with a 0.1 to 0.2 millimeter (mm).

Through the design that the lower die B2 is provided with the positioning structure B21, the core A5 can be stably arranged on the lower die B2, so that the situation that the core A5 is inclined relative to the lower die B2 in the manufacturing process is avoided, and the situation that the coil A2 in the finally formed inductor A is also not inclined easily is avoided under the situation that the core A5 is not inclined easily. As shown in fig. 4, that is, the inductor a manufactured by the inductor manufacturing method of the present invention has the coils A2 arranged in a regular manner in a longitudinal section thereof; on the contrary, in the longitudinal section of the conventional inductor manufactured by die casting shown in fig. 1, the coil A2 is disposed askew, and the askew coil A2 will directly or indirectly affect the relevant characteristics (such as inductance, magnetic permeability, etc.) of the inductor a.

In the coil disposing step S3, the coil A2 is sleeved on the core, and two ends of the coil A2 may be connected to two copper sheets, and a part of the two copper sheets will become the pin A3 of the inductor a. In the powder filling step S4, the mold B is filled with the powder A4, and the powder A4 filled in the mold B covers the core A5, but a part of each copper sheet is not covered by the powder A4. In the molding step S5, an upper mold B1 and the lower mold B2 having substantially the same temperature are pressed against the powder A4 and the core A5 in a middle mold B and a lower mold B2 together, so that the powder A4 and the core A5 are sintered into the package A1.

As shown in fig. 5, it is worth mentioning that, in a preferred application, an end of the core A5 opposite to the positioning structure B21 fixed on the lower mold B2 may be a round chamfer with a radius of 0.1 to 0.2 millimeters (mm), so that when the end of the core A5 and the positioning structure B21 of the lower mold B2 are fixed to each other, and a person or a device related thereto sleeves the coil A2 on the core A5, the coil A2 can be sleeved on the core A5 relatively easily.

As described above, in the inductor manufacturing method of the present invention, by the design of the preheating step S1, a part of the adhesive in the core A5 can be dissipated, so that the hardness of the core A5 is increased, and further, cracks are not easily generated in the longitudinal section of the finally manufactured inductor a. Specifically, as shown in fig. 1, the conventional inductor manufactured by die casting is prone to crack at the approximate center of the longitudinal section, while the inductor a manufactured by the inductor manufacturing method of the present invention is not prone to crack at the center of the longitudinal section.

It should be noted that, as shown in fig. 4, in the longitudinal section of the inductor a manufactured by the inductor manufacturing method of the present invention, if the inductor a is viewed by naked human eyes, the core and the cured powder are not easily distinguished, and the naked eyes will see the integrated package A1, so that even if the inductor is in a relatively severe temperature change, the package A1 is not easily subject to failure due to thermal expansion and contraction of the material. As shown in fig. 1, in contrast to the conventional inductor manufactured by die casting, in a longitudinal section of the inductor, the portion surrounded by the coil and the rest portion located at the periphery of the coil can be easily seen, and a boundary is clearly present between the two portions, so that when a relatively severe temperature change occurs in an environment where the inductor is located, the boundary may be expanded into cracks due to different shrinkage rates, thermal expansion and contraction, and the like, and further, related characteristics (such as inductance and permeability) of the inductor in use may be reduced.

Referring to fig. 6 to 13 together, fig. 6 is a schematic flow chart of a second embodiment of the inductor manufacturing method of the present invention, fig. 7 is a schematic view of a middle mold and a lower mold of the inductor manufacturing method of the present invention, fig. 8 is a schematic cross-sectional view of the middle mold and the lower mold of the inductor manufacturing method of the present invention, and fig. 9 to 13 are schematic views corresponding to partial steps of the second embodiment of the inductor manufacturing method of the present invention. As shown in fig. 6, the inductor manufacturing method of the present embodiment includes the following steps:

a preheating step S1: heating the core body;

a core placing step S2: placing the heated core A5 in a mold (as shown in fig. 9);

a powder pre-filling step SX: heating the mold to make the temperature of the mold reach a predetermined temperature, filling the mold with the powder A4, and making the height H2 (shown in FIG. 10) of the filled powder A4 not lower than one third (shown in FIG. 10) of the height H1 (shown in FIG. 10) of the space in the mold;

a waiting step SW: waiting for at least a preset time to solidify at least a part of the powder A4 in the mould B;

a coil disposing step S3: coil A2 is placed in mold B (as shown in fig. 11);

a powder filling step S4: filling the mold B with the powder A4 (as shown in fig. 12); and

a molding step S5: the mold B is heated and pressurized to mold the powder into a package A1 (shown in fig. 13).

As shown in fig. 7 to 9, the mold may include an upper mold B1, a middle mold B3 and a lower mold B2. The middle mold B3 has a first groove B31 and two second grooves B32, the depth of the first groove B31 is greater than the depth of each second groove B32, the first groove B31 is located between the two second grooves B32, and the first groove B31 is communicated with the two second grooves B32. The lower die B2 is arranged in the middle die B3, and the positioning structure B21 is formed on the top surface of the lower die B2. The top surface of the lower die B2 and the first groove B31 of the middle die B3 form a containing groove SP together, and the containing groove SP is used for containing the powder A4.

As shown in fig. 9 and 10, the preheating step S1 is to heat the middle mold B3 and the lower mold B2 (of course, the upper mold B1 may be heated at the same time), and in the core body placing step S2, one end of the core body A5 is engaged with the positioning structure B21 of the lower mold B2, and the core body A5 is correspondingly positioned in the accommodating groove SP. In the step SX of pre-filling powder, the powder A4 is filled into the containing groove SP.

As shown in fig. 11, in the coil disposing step S3, the two conductive sheet bodies a21 connected to the two ends of the coil A2 are correspondingly disposed in the two second grooves B32. As shown in fig. 12 and 13, in the powder filling step S4 and the forming step S5, the two conductive sheet bodies a21 located in the two second grooves B32 will not be pressed by the upper mold B1, and when the powder A4 is formed into the package body A1, the two conductive sheet bodies a21 will become the two pins A3 after being properly bent.

In one embodiment, the predetermined temperature in the pre-powdering step SX may be between 100 and 180 degrees celsius (° c), and the predetermined time in the waiting step SW may be between 5 and 10 seconds; of course, the predetermined temperature and the predetermined time may be changed according to the material of the powder, the size of the package A1 (shown in fig. 3), and the like. In practical applications, in the step SX of pre-filling powder, the mold may be heated first and then the powder is filled into the mold, or the powder may be filled into the mold first and then the mold is heated.

Through the design of the pre-powder filling step SX and the waiting step SW, the core A5 is firmly disposed in the mold B through the solidified powder A4, so that the core A5 is not prone to be skewed in the subsequent steps, and accordingly, the coil A2 sleeved on the core A5 is not prone to be skewed, and the finally manufactured inductor a is not prone to be skewed in the longitudinal section (as shown in fig. 4) of the inductor a.

In the conventional inductor manufactured by die casting, in addition to the cracks in the portion surrounded by the coil often appearing in the longitudinal section (as shown in fig. 1), the skew condition caused by the irregular arrangement of the partial coils is also often found, and the characteristics of the inductor are also directly or indirectly influenced by the irregular arrangement, skew and the like of the coils. In the inductor manufacturing method of the present invention, the lower mold B2 is provided with the positioning structure B21, so that one end of the core body is fixed to the positioning structure, or the design of the powder pre-filling step SX and the waiting step SW is adopted, so that the finally manufactured inductor a is relatively unlikely to have coil skew or crack in the longitudinal section (as shown in fig. 4).

It is particularly emphasized that, as shown in fig. 5, the core A5 of the present invention has a columnar structure, and by the design of forming the positioning structure B21 in the lower mold B2, the core A5 can be vertically disposed in the lower mold B2, and by the design of the pre-powder filling step SX and the waiting step SW, the core A5 can be still vertically disposed in the lower mold B2 in the subsequent steps, so as to ensure that the finally manufactured inductor is in the longitudinal section thereof, and the coil is not easily skewed.

In one embodiment, in the waiting step SW, the powder A4 may not be completely solidified, and in the coil placing step S3, a part of the coil A2 may be immersed in the powder A4 in the mold B, and by designing the powder A4 in which the coil A2 is immersed in the mold B, the coil A2 may be more stably disposed in the mold B, so that the finally manufactured inductor a is not prone to a skew condition of the coil A2 in a longitudinal section thereof.

It should be noted that the shape of the upper mold B1 shown in fig. 9-13 of the present embodiment is only an exemplary aspect, in practical applications, the end surface of the upper mold B1 facing the middle mold B3 may be recessed to form a groove corresponding to the receiving slot SP, and the groove of the upper mold B1 and the receiving slot SP may be filled with powder together to form a package body with a specific shape.

Referring to fig. 3 to 5 again, fig. 3 is a schematic diagram of an inductor manufactured by the inductor manufacturing method of the present invention, and fig. 4 is a schematic diagram of a longitudinal section of the inductor of fig. 3. As shown in fig. 3, the inductor a of the present invention includes a package A1, two leads A3, and a bump structure a12. A coil A2 is arranged in the package body A1, and two ends of the coil A2 are connected with two pins A3. A bottom surface a11 of the package A1 has a protruding structure a12, and the protruding structure a12 is a portion where the core A5 and the positioning structure B21 are connected to each other (as shown in fig. 5).

In summary, the inductor and the method for manufacturing the same according to the present invention are not prone to crack or coil skew in the longitudinal section, and are not prone to failure during operation.

The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, so that the equivalent technical changes made by using the contents of the present specification and the drawings are included in the protection scope of the present invention.

Claims

1. A method for manufacturing an inductor, the inductor comprising a package, a coil, and two pins, the coil being disposed in the package, the two pins being connected to two ends of the coil, and a portion of each of the two pins being exposed at a bottom surface of the package, the method comprising:

a preheating step: heating a core;

a core body placing step: placing the heated core in a mold;

a step of powder pre-filling: filling a powder into the mold reaching a preset temperature, wherein the height of the filled powder is not less than one third of the height of the space in the mold;

a waiting step: waiting for at least a preset time to solidify at least a part of the powder in the mould;

a coil placement step: disposing the coil in the mold;

firstly, powder filling step: filling the die with the powder; and

a forming step: and heating and pressurizing the die to mold the powder into the packaging body.

2. The method of claim 1, wherein in the coil disposing step, a portion of the coil is immersed in the powder in the mold.

3. The method of claim 1, wherein the predetermined temperature is between 100 and 180 degrees celsius.

4. The method of claim 1, wherein the predetermined time is 5 to 10 seconds.

5. The method of claim 1 wherein said preheating step heats said core to a temperature of 100 to 180 degrees celsius.

6. The method for manufacturing an inductor according to claim 1, wherein the powder comprises metal soft magnetic powder and an adhesive, the adhesive of the powder has a concentration of 0.5wt% to 10wt%, the core comprises metal soft magnetic powder, and the core has a density higher than that of the package.

7. The method for manufacturing an inductor according to claim 1, wherein in the step of disposing the core, one end of the core is connected to a positioning structure of a lower mold of the mold, and the core is fixedly disposed on the lower mold through the positioning structure.

8. An inductor, characterized in that the inductor is manufactured by the inductor manufacturing method according to claim 7, the bottom surface of the package body of the inductor has a protruding structure, and the protruding structure is a portion where the core and the positioning structure are connected with each other.