Inductor manufacturing method and inductor

Abstract

To relate to the technical field of an inductor, and in particular to an inductor manufacturing method and an inductor.SOLUTION: A coil and a magnetic core are fixed by a first injection molding process to form a primary molded body, and then a primary molded body and an insert are fixed to mold an inductor. As compared with the traditional potting process, this application uses a new injection molding process, which has high molding efficiency. In addition, the two-stage injection molding process ensures that the molding material can easily enter smaller gaps and more appropriately fill corners. This also contributes to reducing the injection pressure, which can reduce the impact force received by the magnetic core and reduce the risk of cracking and breaking the magnetic core.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the technical field of inductors, and more particularly to a method for manufacturing an inductor and an inductor. [Background technology]

[0002] Current high-power inductors for automobiles generally use a potting process (encapsulation molding) using thermally conductive silicone. The thermally conductive silicone fixes the inductor coil and magnetic core, and at the same time, it can conduct the heat generated by the inductor coil and magnetic core. However, the manufacturing process of potted inductors is relatively complicated, and the manufacturing efficiency of inductors is low. Summary of the Invention

[0003] The present invention provides a method for manufacturing an inductor, which can be used to improve the technical problem of low efficiency in forming an inductor in the prior art.

[0004] Another object of the present invention is to provide an inductor.

[0005] According to a first aspect, in one embodiment, there is provided a method of forming an inductor. In this method, the coil and the magnetic core are fixed together by a primary molded body obtained by a first injection molding process, so that the coil, the magnetic core and the primary molded body form a primary molded body, and then the insert in the inductor and the primary molded body are fixed together by a secondary molded body obtained by a second injection molding process.

[0006] Furthermore, in an embodiment, the injection pressure of the secondary injection molding process is greater than the injection pressure of the primary injection molding process.

[0007] Furthermore, in one embodiment, in the primary injection molding process, a lead terminal fixing portion is injection molded onto the coil lead terminal of the coil, so that the lead terminal fixing portion fixes the coil lead terminal.

[0008] Furthermore, in one embodiment, in the secondary injection molding process, a part of the secondary molded body is injection molded onto the lead-out terminal fixing portion for reinforcement.

[0009] Furthermore, in one embodiment, during the primary injection molding process, the magnetic core is positioned by contacting it with a primary injection positioning mold, and the primary injection positioning mold forms a primary process hole during the primary injection process, and during the secondary injection process, at least one secondary injection positioning mold is inserted into the primary process hole to position the primary molded body, and the secondary injection positioning mold forms a secondary process hole during the secondary injection process, and at least one of the secondary process holes communicates with the primary process hole to form a through hole.

[0010] According to a second aspect, in one embodiment, an inductor is provided that includes a coil, a magnetic core, a primary mold body, and a secondary mold body, wherein the primary mold body fixes the coil and the magnetic core, and at least a portion of the primary mold body is located in a gap between the coil and the magnetic core.

[0011] The inductor further includes an insert, and the secondary mold body is molded over the primary mold body to secure the insert.

[0012] Furthermore, in an embodiment, the coil has an exposed first heat dissipation surface, and the secondary molded body has a heat conduction pad positioning protrusion for pressing a heat conduction pad attached to the first heat dissipation surface, and in a direction perpendicular to the first heat dissipation surface, the tip surface of the heat conduction pad positioning protrusion is flush with or lower than the plane on which the first heat dissipation surface is located.

[0013] Furthermore, in an embodiment, the coil has a coil pull-out terminal, the primary molded body includes a pull-out terminal fixing portion injection-molded on the coil pull-out terminal, the pull-out terminal fixing portion fixes the coil pull-out terminal, and a portion of the secondary molded body is injection-molded onto the pull-out terminal fixing portion for reinforcement.

[0014] Furthermore, in an embodiment, the primary mold body has a primary process hole for contacting and positioning a primary positioning die to the magnetic core, the coil, the magnetic core and the primary mold body form a primary molded body, the secondary mold body has a secondary process hole for contacting and positioning a secondary positioning die to the primary molded body, and at least one of the secondary process holes communicates with the primary process hole to form a through hole.

[0015] Further, in an embodiment, the primary mold body includes a primary mold body layer covering the side of the magnetic core facing away from the coil, and the secondary mold body includes a secondary mold body layer located outside the primary mold body layer, and the ratio of the thickness of the secondary mold body layer to the thickness of the primary mold body layer is greater than 1.

[0016] Based on the inductor manufacturing method of the above embodiment, the coil and magnetic core are fixed together by primary injection molding to form a primary compact, and then the primary compact and insert are fixed together to form the inductor. Compared to the conventional potting process, this application uses a new injection molding process, which has high molding efficiency. Furthermore, the two-stage injection molding process ensures that the molding material can easily enter smaller gaps and more appropriately fill corners. This also contributes to reducing the injection pressure, thereby reducing the impact force on the magnetic core and reducing the risk of cracking or breaking the magnetic core. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a structural schematic diagram of an inductor according to one embodiment of the present invention. [Figure 2]FIG. 2 is another perspective view of an inductor according to one embodiment of the present invention. [Figure 3] FIG. 3 is a structural schematic diagram of an inductor and a thermal conductive pad according to an embodiment of the present invention. [Figure 4] FIG. 4 is a schematic diagram showing the positions of the coils and magnetic cores in one embodiment of the present invention. [Figure 5] FIG. 5 is a schematic structural view of a primary molded body according to one embodiment of the present invention. [Figure 6] FIG. 6 is a structural schematic diagram of a primary molded body in one embodiment of the present invention, seen from another angle. [Figure 7] FIG. 7 is a diagram showing the structure of a secondary mold body according to one embodiment of the present invention. [Figure 8] FIG. 8 is a schematic structural diagram of another inductor according to an embodiment of the present invention. [Figure 9] FIG. 9 is a top view of another inductor in accordance with an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention will be described in more detail below in conjunction with specific embodiments and drawings. Similar components in different embodiments have the same associated component numbers. In the following detailed description, numerous details are described to facilitate a better understanding of the present application. However, those skilled in the art will readily recognize that some features may be omitted or substituted by other components, materials, or methods under different circumstances. In some cases, some operations related to the present application are not shown or described herein to avoid overwhelming the kernel portion of the present application with excessive description. However, those skilled in the art will be able to complete uncorrelated operations without needing to describe these related operations in detail based on the description herein and general knowledge in the art.

[0019] Furthermore, the features, operations, or characteristics described herein may be combined in any suitable manner to form various embodiments. Additionally, the steps or actions in the method descriptions may be reordered or resequenced in ways apparent to those skilled in the art. Thus, various orders in the specification and figures are merely for clarity in illustrating particular embodiments and do not imply a required order unless otherwise specified that a particular order is required.

[0020] The numbering of parts in this specification, such as "first", "second", etc., is used only to distinguish between the described items and does not have any ordering or technical meaning. Unless otherwise specified, "connected" and "coupled" in this application both include direct and indirect connection (coupling).

[0021] 1 to 7, in one embodiment, a method for forming an inductor includes fixing a coil 1 and a magnetic core 2 to each other by a primary molded body 3 obtained by a primary injection molding process. Here, the coil 1, the magnetic core 2, and the primary molded body 3 are integrated to form a primary molded body 5, and then fixing an insert 4 in the inductor and the primary molded body 5 together by a secondary molded body 6 formed by a secondary injection molding process.

[0022] The inductor of the present disclosure can be manufactured using two injection molding processes, which provides higher molding efficiency than conventional potting molding methods. Furthermore, the two-stage injection molding process ensures that the molding material can easily enter smaller gaps and more appropriately fill corners. This also contributes to reducing the injection pressure, thereby reducing the impact force received by the magnetic core 2 and reducing the risk of cracking or breaking the magnetic core 2. The primary molded body 3 formed by the first injection molding process can be used as a positioning reference for the second injection molding process, making it easier to ensure the positional accuracy of each component in the inductor.

[0023] To further improve process stability, in one embodiment, the injection pressure in the secondary injection molding process is greater than the injection pressure in the primary injection molding process. After the coil 1 and the magnetic core 2 are fixed in place by the primary injection molding process, the coil 1 and the magnetic core 2, protected by the primary molded body 3, can withstand the greater injection pressure. Therefore, by increasing the injection pressure in the secondary injection molding process to be greater than the injection pressure in the primary injection molding process, the pressure in the primary injection molding process can be reduced while completing the secondary injection molding process of the inductor, thereby providing better protection for the magnetic core 2. In some other embodiments, the injection pressure in the secondary injection molding process may be equal to the injection pressure in the primary injection molding process; of course, if the strength of the magnetic core 2 meets the requirements, the injection pressure in the secondary injection molding process may be less than the injection pressure in the primary injection molding process.

[0024] To facilitate the secondary injection molding process, in one embodiment, as shown in Figure 5, a lead terminal fixing part 31 is injection molded onto the coil lead terminal 11 of the coil 1 during the primary injection molding process. The lead terminal fixing part 31 fixes the coil lead terminal 11. When the coil lead terminal 11 is fixed to the primary molded body 3, it is less likely to shake, and a dedicated positioning mold is not required during the secondary injection molding process, simplifying the secondary injection molding process and improving molding efficiency.

[0025] In this embodiment, to further improve the fixing strength of the coil lead terminal 11, a portion of the secondary molded body 6 is injection molded onto the lead terminal fixing portion 31 for reinforcement during the secondary injection molding process, as shown in Figures 1 and 7. The secondary molded body 6 reinforces the coil lead terminal 11, improving its stability.

[0026] 1, 5, and 7, the lead terminal fixing portion 31 is formed to protrude from the primary molded body 3, and is injection molded into a strip-like shape on the coil lead terminal 11. When the injection molding of the secondary molded body 6 is completed, it partially surrounds the lead terminal fixing portion 31. That is, a fixing groove 64 is formed in the secondary molded body 6, and the lead terminal fixing portion 31 is positioned within the fixing groove 64.

[0027] In another embodiment, the coil lead-out terminal 11 may be fixed by the secondary molded body 6 in the secondary injection molding process.

[0028] 1 and 2, after the primary mold body 3 and secondary mold body 6 of the inductor are injection molded, the insert 4 is fixed in the secondary mold body 6. In one embodiment, the insert 4 includes a fixing nut 41 for fixing the inductor and a wire connection nut 42 for connecting wiring. In other embodiments, the insert 4 may be provided as needed, and may include, for example, only a fixing nut or only a wire connection nut. Of course, other types of components, such as a support member, a sensor, etc., may also be used as the insert.

[0029] 1, in one embodiment, the inductor includes a conductive bar 7 fixed to a coil lead-out terminal 11 of a coil 1. Specifically, the conductive bar 7 and the coil 1 can be connected by any feasible conductive connection method, such as welding, adhesive bonding, or fastener connection.

[0030] 1 and 2, in one embodiment, the conductive bar 7 is attached to the surface of the secondary molded body 6, one end of which is fixed to the coil lead terminal 11, and the other end of which is connected to the connecting nut 42. This makes the conductive bar 7 more stable and less likely to loosen when subjected to external force.

[0031] In one embodiment, the inductor is a high-power inductor for use in automobiles, etc. High-power inductors need to dissipate heat, so heat dissipation issues must be taken into consideration.

[0032] 1 and 2, in one embodiment, to improve the heat dissipation capability of the inductor, after the inductor is manufactured, both sides of the coil 1 are exposed, allowing heat to be dissipated or to be in close contact with a thermal conduction pad for heat conduction to the thermal conduction pad.

[0033] In this embodiment, to further improve the heat dissipation performance of the inductor, as shown in FIGS. 8 and 9 , the magnetic core 2 is positioned by contacting it with a primary injection positioning mold during the primary injection molding process. The primary injection molding positioning mold forms a primary process hole 33 during the primary injection molding process. During the secondary injection molding process, at least one secondary injection molding positioning mold is inserted into the primary process hole 33 to position the primary molded body 5. The secondary injection molding positioning mold may form a secondary process hole 62 during the secondary injection molding process. At least one secondary process hole 62 may communicate with the primary process hole 33 to form a through hole 8. This allows the magnetic core 2 to directly dissipate heat to the outside, improving the heat dissipation efficiency of the inductor.

[0034] 5 to 7, there may be a plurality of primary process holes 33, and a primary process hole 33 may be provided on each side of the primary formed body 5. Also, several primary process holes 33 may be provided at the corners of the primary formed body 5. Also, a plurality of secondary process holes 62 may be provided.

[0035] The present disclosure further provides an inductor manufactured using the above-described inductor manufacturing method, which will be described in detail below.

[0036] 1 to 7, the inductor includes a coil 1, a magnetic core 2, a primary molded body 3, and a secondary molded body 6. The primary molded body 3 fixes the coil 1 and the magnetic core 2, and at least a portion of the primary molded body 3 fills the gap between the coil 1 and the magnetic core 2. The inductor may further include an insert 4. The secondary molded body 6 is molded on the primary molded body 3 and fixes the insert 4.

[0037] Furthermore, in one embodiment, the inductor is a high-power inductor applied to automobiles, etc. Since high-power inductors require heat dissipation, heat dissipation issues must be taken into consideration. As shown in FIGS. 1 and 2 , the coil 1 has an exposed first heat dissipation surface 12 and a second heat dissipation surface 13. The first heat dissipation surface 12 faces in the opposite direction from the second heat dissipation surface 13. The first heat dissipation surface 12 and the second heat dissipation surface 13 enable heat to be dissipated to the outside, improving the heat dissipation efficiency of the inductor. In some other embodiments, the coil 1 may have only the first heat dissipation surface 12, and the second heat dissipation surface 13 may be covered by the secondary molded body 6.

[0038] 2 and 3, in one embodiment, the secondary mold body 6 may have a thermal conduction pad positioning protrusion 61. The thermal conduction pad positioning protrusion 61 can press the thermal conduction pad 9 attached to the first heat dissipation surface 12. In a direction perpendicular to the first heat dissipation surface 12, the tip surface of the thermal conduction pad positioning protrusion 61 is lower than the plane on which the first heat dissipation surface 12 is located. This prevents the thermal pad positioning protrusion 61 from affecting the contact between the thermal pad and the first heat dissipation surface 12. In some other embodiments, the tip surface of the thermal pad positioning protrusion 61 may be flush with the plane of the first heat dissipation surface 12.

[0039] As shown in Figures 2 and 3, more specifically, the inductor can adopt a water-cooled heat dissipation method. In this case, a thermal conduction pad 9 can be used to transfer heat between the inductor and the water-cooled plate. Heat generated in the inductor is transferred to the water-cooled plate via the thermal conduction pad 9. When a conventional inductor is used in a vibration environment, the thermal conduction pad 9 is prone to movement relative to the inductor. Over time, the thermal conduction pad 9 is prone to separation from the inductor, resulting in reduced heat conduction efficiency. The thermal conduction pad positioning protrusion 61 can press the thermal conduction pad 9, and a recess is formed in the thermal conduction pad 9, making the thermal conduction pad 9 less likely to move relative to the inductor, thereby improving the heat dissipation stability of the inductor.

[0040] Specifically, the number of the heat conduction pad positioning protrusions 61 is plural, and the heat conduction pad positioning protrusions 61 are arranged along the circumferential direction of the first heat dissipation surface 12.

[0041] 1, 5 and 7, in one embodiment, the coil 1 has a coil lead terminal 11, the primary molded body 3 includes a lead terminal fixing portion 31 injection molded onto the coil lead terminal 11, the lead terminal fixing portion 31 fixes the coil lead terminal 11, and a portion of the secondary molded body 6 is injection molded onto the lead terminal fixing portion 31 for reinforcement. The secondary molded body 6 reinforces the coil lead terminal 11, improving the stability of the coil lead terminal 11.

[0042] 1, 5, and 7, the lead terminal fixing portion 31 is formed to protrude from the primary molded body 3, and is injection molded into a strip-like shape on the coil lead terminal 11. When the injection molding of the secondary molded body 6 is completed, it partially surrounds the lead terminal fixing portion 31. That is, a fixing groove 64 is formed in the secondary molded body 6, and the lead terminal fixing portion 31 is positioned within the fixing groove 64.

[0043] In another embodiment, the coil lead-out terminal 11 may be fixed by the secondary molded body 6 in the secondary injection molding process.

[0044] As shown in Figures 8 and 9, in one embodiment, the primary molded body 3 has primary process holes 33. The primary process holes 33 are used by the primary positioning die to contact the magnetic core 2 and position the magnetic core 2. The coil 1, the magnetic core 2, and the primary molded body 3 form a primary molded body 5. The secondary molded body 6 has secondary process holes 62. The secondary process holes 62 are used by the secondary positioning die to contact the primary molded body 5 and position the primary molded body 5. At least one secondary process hole 62 communicates with the primary process hole 33 to form a through hole 8. This allows the through hole 8 to directly dissipate heat from the magnetic core 2 to the outside, improving the heat dissipation efficiency of the inductor. In another embodiment, the primary process holes 33 and the secondary process holes 62 do not need to communicate with each other, in which case heat dissipation through these process holes is not necessary.

[0045] 5 to 7, in one embodiment, there are multiple primary process holes 33, and one primary process hole 33 is provided on each side of the primary molded body 5. In addition, at least one primary process hole 33 may be provided in a corner of the primary molded body 5. Multiple secondary process holes 62 may also be provided.

[0046] 8 and 9, in this embodiment, the through-holes 8 and the heat conduction pad positioning protrusions 61 are located on the same side of the secondary molded body 6. Therefore, part of the heat released through the through-holes 8 is removed by the heat sink in contact with the heat conduction pad.

[0047] 1 and 5, in one embodiment, the primary mold body 3 includes a primary mold body layer 32 that covers the side of the magnetic core 2 facing away from the coil 1. The secondary mold body 6 includes a secondary mold body layer 63 that is located on the outside of the primary mold body layer 32. The ratio of the thickness of the secondary mold body layer 63 to the thickness of the primary mold body layer 32 is greater than 1. This ensures that the thickness of the primary mold body 3 is small, which results in a smaller primary injection pressure and reduces the risk of damaging the magnetic core 2 during injection molding.

[0048] Specifically, in one embodiment, the thickness of the secondary mold body layer 63 and the thickness of the primary mold body layer 32 are determined according to the size of the inductor.

[0049] It should be understood that in one embodiment, as shown in Fig. 4, the coil 1 is disposed in the space surrounded by the magnetic core 2, and the side of the magnetic core 2 facing away from the coil 1 is the outer circumferential surface 21 of the magnetic core 2. As shown in Figs. 1, 5, and 7, the thickness of the primary mold body layer 32 and the thickness of the secondary mold body layer 63 are both defined at the position where the primary mold body 3 and the secondary mold body 6 are stacked, and the position where the primary mold body 3 and the secondary mold body 6 are not stacked does not belong to the range of the mold body layer. For example, in the primary mold body 3, the portion between the magnetic core 2 and the coil 1 does not belong to the primary mold body layer 32, and in the secondary mold body 6, the position where the insert 4 is located and the portion inside the primary process hole 33 do not belong to the secondary mold body layer 63.

[0050] In some other embodiments, in some circumstances, the ratio of the thickness of the primary mold body layer 32 to the thickness of the secondary mold body layer 63 may be 1 or greater.

[0051] Although the present invention has been described above using specific examples, these examples are merely for the purpose of aiding understanding of the present invention and are not intended to limit the present invention. Those skilled in the art to which the present invention pertains may make further simple inferences, modifications, or substitutions based on the concept of the present invention. [Explanation of symbols]

[0052] Explanation of Reference Numbers in Parentheses in the Figures In the drawings, the reference number in parentheses refers to both the feature represented by the number inside the parentheses and the feature represented by the number outside the parentheses.

[0053] 1 coil 11 Coil lead-out terminal 12 1st heat dissipation surface 13 Second heat dissipation surface 2 magnetic core 21 Outer surface 3 Primary mold body 31 Output terminal fixing part 32 Primary mold layer 33 Primary process hole 4 Inserts 41 Fixing nut 42 Wire connection nut 5 Primary molded body 6 Secondary mold body 61 Heat conduction pad positioning protrusion 62 Secondary process hole 63 Secondary mold layer 64 Fixed groove 7 Conductive Bar 8 through holes 9 Thermal pad

Claims

1. A method for manufacturing an inductor, comprising: The method includes a step of fixing a coil and a magnetic core to each other by a primary molded body obtained by a primary injection molding process, so that the coil, the magnetic core, and the primary molded body form a primary molded body, and then fixing an insert in an inductor and the primary molded body to each other by a secondary molded body obtained by a secondary injection molding process, the insert includes a fixing nut for fixing the inductor and a connecting nut for wiring, a lead terminal fixing portion is injection molded on a coil lead terminal of the coil in the primary injection molding process so that the lead terminal fixing portion fixes the coil lead terminal, and a portion of the secondary molded body is injection molded on the lead terminal fixing portion for reinforcement in the secondary injection molding process; The method for manufacturing an inductor further includes a step of fixing a conductive bar of the inductor to the coil lead terminal.

2. 2. The method for manufacturing an inductor according to claim 1, wherein the injection pressure in the secondary injection molding process is higher than the injection pressure in the primary injection molding process.

3. The method for manufacturing an inductor described in claim 1 or 2, characterized in that in the primary injection process, the magnetic core is positioned by contacting it with a primary injection positioning mold, the primary injection positioning mold forms a primary process hole in the primary injection process, and in the secondary injection process, at least one secondary injection positioning mold is inserted into the primary process hole to position the primary molded body, and at least one of the secondary process holes formed by the secondary injection positioning mold in the secondary injection process is connected to the primary process hole to form a through hole.

4. An inductor comprising a coil, a magnetic core, a primary molded body, and a secondary molded body, wherein the primary molded body fixes the coil and the magnetic core, and at least a portion of the primary molded body is located in a gap between the coil and the magnetic core; the inductor further includes an insert, the secondary molded body is formed on the primary molded body to fix the insert, and the insert includes a fixing nut for fixing the inductor and a wiring nut for wiring; the coil has a coil lead terminal, the primary molded body includes a lead terminal fixing portion injection-molded on the coil lead terminal, the lead terminal fixing portion fixes the coil lead terminal, and a portion of the secondary molded body is injection-molded on the lead terminal fixing portion for reinforcement; The inductor includes a conductive bar fixed to the coil lead terminal.

5. 5. The inductor according to claim 4, wherein the coil has an exposed first heat dissipation surface, the secondary molded body has a heat conduction pad positioning protrusion for pressing a heat conduction pad attached to the first heat dissipation surface, and in a direction perpendicular to the first heat dissipation surface, a tip surface of the heat conduction pad positioning protrusion is flush with or lower than the plane on which the first heat dissipation surface is located.

6. The inductor described in claim 4 or 5, characterized in that the primary molded body has a primary process hole for contacting a primary positioning die with the magnetic core to position it, the coil, the magnetic core and the primary molded body form a primary molded body, the secondary molded body has a secondary process hole for contacting a secondary positioning die with the primary molded body to position it, and at least one of the secondary process holes communicates with the primary process hole to form a through hole.

7. The inductor described in claim 4 or 5, characterized in that the primary molding body includes a primary molding body layer covering the side of the magnetic core facing away from the coil, the secondary molding body includes a secondary molding body layer located outside the primary molding body layer, and the ratio of the thickness of the secondary molding body layer to the thickness of the primary molding body layer is greater than 1.

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