Pre-terminated inductor and method and apparatus for manufacturing the same

Abstract

To provide an inductor, and a method and an apparatus for manufacturing the inductor.SOLUTION: The inductor 100 includes a preformed conductive coil 200 that includes an inductor body having a medial portion between a first terminal lead 210 and a second terminal lead 220 and a magnetic material surrounding at least the medial portion. At least a portion of each of the first and second terminal lead portions of the preformed conductive coil is exposed outside the inductor body. The method includes providing a one piece conductive coil having a substantially curved middle portion and first and second terminal leads, and molding a magnetic material around at least the middle portion of the preformed conductive coil such that at least a portion of the first and second terminal leads of the single molded conductive coil are exposed outside the inductor body.SELECTED DRAWING: Figure 1B

Description

Related Applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 62 / 984,584, filed March 3, 2020, and U.S. Non-Provisional Patent Application No. 17 / 187,161, filed February 26, 2021, both of which are incorporated herein by reference. [Technical Field]

[0002] The present application relates to the field of electronic components, and more particularly to inductors and methods / apparatus for manufacturing the same. [Background technology]

[0003] Generally speaking, inductors are passive two-terminal electrical components that resist changes in electrical current passing through them. An inductor consists of a conductor, such as a wire, wound into a coil. When current flows through the coil, energy is temporarily stored in the magnetic field within the coil. When the current through the inductor changes, the time-varying magnetic field induces a voltage in the conductor, according to Faraday's law of electromagnetic induction.

[0004] Some known inductors are formed using thin conductive wire sandwiched between or wrapped around multi-piece molded magnetic core material, typically in a C-shape, E-shape, ring, or other shape that can be attached with an adhesive. When formed from two separate pieces of magnetic core material, the inductor core design is dominated by open space. This open space negatively impacts the operation and performance of the inductor.

[0005] Other known inductors are formed by pressing a powdered magnetic material around a conductive body. In such known inductors, the conductive coil tends to move within the die, particularly during pressing. This can result in the conductive coil moving within the core, degrading the operation and performance of the inductor.

[0006] Some known inductors typically require welding the conductive coil to a lead frame to hold the pieces together during formation. After the magnetic material is pressed around the conductive coil, the leads must be formed, for example, by cutting the lead frame and bending the leads. Post-processing steps such as cutting and bending can introduce cracks and other defects into the integrity of the conductive wire and formed magnetic material, resulting in increased waste and additional work.

[0007] When it comes to inductors, a problem within the industry arises regarding the inspection of the lead area suitable for solder connection. For example, this inspection can be performed by X-ray or by automated optical inspection (AOI), where automated optical inspection (AOI) systems are used to inspect, for example, semiconductor devices and printed circuit boards (PCBs) for defects. It is desirable to manufacture inductors with leads that allow the use of AOI, which is less costly than X-ray inspection.

[0008] There remains a need for a simple and economical method for manufacturing inductors that utilizes the smallest possible footprint, maximizing usable core area while minimizing raw material waste. Summary of the Invention

[0009] An inductor and a method for manufacturing the inductor are disclosed.

[0010] According to one aspect, the present invention provides an inductor including a preformed conductive coil having a middle portion between a first terminal lead portion and a second terminal lead portion, and an inductor body having a magnetic material surrounding at least the middle portion of the preformed conductive coil, wherein at least a portion of each of the first and second terminal lead portions of the preformed conductive coil is exposed outside the inductor body.

[0011] In another embodiment, the magnetic material may be magnetic particles molded around the middle portion of the conductive coil and a portion of the first and second terminal lead portions of the conductive coil, and the magnetic particles may be powdered or granular magnetic material, particularly powdered iron particles.

[0012] Alternatively, the conductive coil can be formed by bending a conductive material into a predetermined shape, which may be circular, semicircular, oval, or omega shaped.

[0013] In another embodiment, the inductor body can be configured as a package. The package has a bottom side (i.e., a lead side), a top side, a right side, a left side, a front side, and a back side. The portions of the first and second terminal leads exposed outside the inductor body can be located along the bottom side or the lead side of the inductor body. Each of the first and second terminal leads includes a bottom portion having an exposed portion located along the bottom side of the inductor body, and a side portion terminating along one of the right and left sides of the inductor body. Each of the right and left sides of the inductor body also has a cutout portion, and a side portion of one of the first and second terminal leads is located in the cutout portion. Each side portion of the first and second terminal leads is substantially perpendicular to the bottom portion.

[0014] In another aspect, the presently disclosed subject matter addresses a method for manufacturing an inductor, comprising providing a conductor having a substantially curved central portion and first and second terminal lead portions, and molding a magnetic material around at least the central portion of the formed conductive coil to form an inductor body, with at least portions of the first and second terminal lead portions of the formed conductive coil exposed outside the inductor body. The formed inductor body has a package shape and has a bottom side, a top side, a right side, a left side, a front side, and a back side, with the first and second terminal lead portions exposed along one of the left and right sides and the bottom side of the inductor body. During molding of the magnetic material, the formed conductive coil is placed in a mold assembly, and magnetic material is poured into the mold assembly to press the magnetic material around the conductive coil. When the formed conductive coil is positioned in the mold assembly, the first and second terminal lead portions of the formed conductive coil are seated on first and second shelves formed in the wall of the mold assembly, the first and second shelves having shapes complementary to the first and second terminal lead portions so that the first and second terminal lead portions function as part of the wall of the mold assembly during molding. Each of the first and second shelves further has a narrowed wall portion that forms a complementary notch on the right and left sides of the inductor body, respectively, and a portion of each of the first and second terminal lead portions is located within the respective notch.

[0015] In another aspect, the presently disclosed subject matter addresses an assembly for forming an inductor, the assembly including a preformed conductive coil having a central portion between first and second terminal lead portions, a mold section having a seating channel extending therethrough and a wall surrounding the seating channel, the wall having first and second shelves configured to receive the first and second terminal lead portions of the preformed conductive coil, and at least one punch configured to press magnetic particles around the conductive coil when the conductive coil is positioned within the mold section, the first and second shelves having a complementary shape to the first and second terminal lead portions such that the magnetic particles contact the mold walls when the magnetic particles are pressed around the conductive coil. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] U.S. Patent No. 6,198,375 [Patent Document 2] U.S. Patent No. 6,204,744 [Brief explanation of the drawings]

[0017] [Figure 1A] FIG. 1A is an isometric view of the lead side of an exemplary embodiment of an inductor according to the present invention. [Figure 1B] FIG. 1B is a partial perspective view of the inductor body of FIG. 1A showing the conductive coils. [Figure 1C] FIG. 1C is an isometric view of the front right side of the inductor body shown in FIG. 1A. [Figure 1D] FIG. 1D is a partial perspective view showing the conductive coils of the inductor body of FIG. 1C. [Figure 1E] FIG. 1E is a plan view showing the front side of the inductor shown in FIG. 1A. [Figure 1F]FIG. 1F is a partial perspective view showing the conductive coils of the inductor body of FIG. 1E. [Figure 1G] Figure 1G is a plan view showing the right side of the inductor shown in Figure 1A, which is preferably a mirror image of the right side shown in Figure 1G. [Figure 1H] FIG. 1H is a partial perspective view showing the conductive coils of the inductor body of FIG. 1G. [Figure 2A] FIG. 2A is an isometric view of the front side of an exemplary embodiment of the conductive coil of the present invention shown in FIGS. 1A and 1B. [Figure 2B] FIG. 2B is an isometric view of the top side of the conductive coil shown in FIG. 2A. [Figure 2C] FIG. 2C is an isometric view of the bottom side of the conductive coil shown in FIG. 2A. [Figure 2D] Figure 2D is a plan view of the right side of the conductive coil shown in Figure 2A, where the left side of the inductor in Figure 2A is preferably a mirror image of the right side shown in Figure 2D. [Figure 3] FIG. 3 is a flow diagram illustrating an exemplary method for forming an inductor having preformed terminations according to the present invention. [Figure 4A] FIG. 4A is a plan view of exemplary mold sections for forming an inductor having preformed terminations according to the present invention. [Figure 4B-C] 4B and 4C are perspective views of the mold portion shown in FIG. 4A. [Figure 5A-B] 5A and 5B are perspective views of the mold section of FIG. 4A with the conductive coil seated in the seating channel. [Figure 6A] FIG. 6A is a perspective view of a mold assembly for forming an inductor having preformed terminations according to the present invention. [Figure 6B] FIG. 6B is a cross-sectional view of the die assembly of FIG. 6A showing the conductive coil seated within the die assembly. [Figure 6C]FIG. 6C is a cross-sectional view of the mold assembly of FIG. 6A showing the formed inductor with preformed terminations in accordance with the present invention within the mold assembly. [Figure 7] FIG. 7 is a cross-sectional view of the die assembly of FIG. 4A showing an inductor formed in accordance with the present invention seated within a seating channel. [Figure 8A] FIG. 8A is a partial perspective view of another exemplary embodiment of an inductor according to the present invention showing a conductive coil. [Figure 8B] FIG. 8B is an isometric view of the conductive coil shown in FIG. 8A. [Figure 8C] Figure 8C is a plan view of the right side of the conductive coil shown in Figure 8B, which is preferably a mirror image of the right side shown in Figure 8C. [Figure 9A] FIG. 9A is a partial perspective view of another exemplary embodiment of an inductor according to the present invention showing a conductive coil. [Figure 9B] FIG. 9B is a plan view of the conductive coil shown in FIG. 9A. DETAILED DESCRIPTION OF THE INVENTION

[0018] The following describes an inductor with preformed terminations and a method for manufacturing the inductor using a mold apparatus.

[0019] In the following description, certain terminology is used for convenience only and is not intended to be limiting. The terms "right," "left," "top" and "bottom" refer to directions in the drawings to which reference is made. The singular terms "a," "an," "the," and "the" used in the claims and corresponding portions thereof encompass the plural unless otherwise specified. This term encompasses not only the specifically described term but also derivatives and terms of similar import. For example, the use of "at least one" after two or more elements, such as "A, B, or C," refers to a plurality of A, B, or C, not just one. It should be noted that some of the drawings are in perspective for purposes of explanation, illustration, and demonstration only, and do not imply that certain components will be transparent in their final manufactured form.

[0020] While the description disclosed herein will enable one of ordinary skill in the art to make and use the described embodiments, various modifications, equivalents, variations, combinations, and alternatives will be apparent to those skilled in the art, which modifications, equivalents, variations, combinations, and alternatives are intended to be included within the spirit and scope of the present invention as defined by the claims.

[0021] 1A-1H illustrate an inductor 100 according to one exemplary embodiment disclosed herein. The inductor 100 includes an inductor body 110 that partially surrounds a preformed conductive coil 200. The inductor body 110 is preferably formed from a magnetic material molded around the conductive coil 200. In one embodiment, the inductor body 110 can be formed from an iron-based material. In one embodiment, the inductor body 110 can be composed of, for example, iron and / or metal alloys and / or ferrites, or other materials known in the inductor art and used to form such bodies. In one embodiment, the inductor body 110 can be formed from magnetic particles, such as powdered or granular magnetic materials. In one embodiment, the magnetic particles can be powdered iron particles. In a non-limiting embodiment, the magnetic material may be an inductor body comprised of powdered iron particles, fillers, resins, lubricants, etc., as disclosed in U.S. Pat. No. 6,198,375 ("Inductor Coil Structure") and U.S. Pat. No. 6,204,744 ("High Current, Low Profile Inductor"), both of which are incorporated herein by reference.

[0022] As shown in FIGS. 1A-1H, in one exemplary embodiment, the inductor body 110 is preferably formed into a package having a bottom or lead side 120, a top side 130, a right side 140, a left side 150, a front side 160, and a back side 170. The package shape is not limited to, and may include, for example, a box-like package, a rectangular package, a parallelepiped, any of the above packages with rounded corners (see FIG. 8A), or a package with one or more irregular surfaces. Those skilled in the art will recognize that other inductor shapes can be utilized without departing from the spirit of the present invention. For example, an inductor 100 having preformed terminations in accordance with the present invention may include non-matching mold sections that can be integrated within a mold system. The inductor body 110 is preferably formed around the conductive coil 200 such that the left and right lead portions 210 , 220 of the conductive coil 200 are exposed outside the inductor body 110 along the lead side portions 120 of the inductor body 110 .

[0023] FIGS. 2A-2C illustrate a conductive coil 200 according to an exemplary embodiment described herein. The conductive coil 200 is preferably a preformed member formed from a conductive material, such as a metal plate, sheet, or strip. Acceptable metals for forming the conductive coil 200 include copper, aluminum, platinum, and other metals conventionally used in inductor coils. In an exemplary embodiment, the conductive coil is formed into a preformed member by bending a conductive material into a predetermined shape. The wire that can be used to form the conductive coil 200 is not limited to, and examples include flat wire, square wire, rectangular wire, and round wire. Those skilled in the art will appreciate that other wire shapes are also within the scope of the present invention. The thickness of the conductive coil 200 can be uniform, as shown in FIGS. 2A-2C, or can vary, as shown in FIGS. 8A-8C and 9A-9B. In one embodiment, the conductive coil 200 is a single, integral member. In another embodiment, the conductive coil 200 can be made of multiple pieces of material joined together, such as by welding. However, the conductive coil 200 must be sufficiently formed before the molding process forms the inductor body around the conductive coil.

[0024] Conductive coil 200 is preferably formed in a configuration that is easy to manufacture and allows for high efficiency and performance in a small volume that minimizes waste. The shape of conductive coil 200 is designed to optimize the path length that can fit into the available space within inductor body 110 while minimizing resistance and maximizing inductance.

[0025] As shown in the exemplary embodiment of FIGS. 2A-2C, conductive coil 200 preferably has right and left ends that define right and left lead portions 210, 220 and middle portion 230. Right and left lead portions 210, 220 are preferably formed into an L- or U-shape. Those skilled in the art will recognize that when right and left lead portions 210, 220 are formed into an L- or U-shape, such L- or U-shape may comprise a substantially right-angled portion, as shown, for example, in FIGS. 2A-2C, or a substantially circular portion, as shown, for example, in FIGS. 8A-8C (described below). Middle portion 230 is preferably formed into a circular or semicircular shape, although other shapes can be used based on the desired inductor characteristics. In one embodiment, middle portion 230 may be a single semicircular portion, as shown, for example, in FIGS. 2A-2C, or an oval portion, as shown, for example, in FIGS. 9A-9B. Additionally, middle portion 230 may comprise one or more wound circular segments or stacked coils. As shown in the preferred embodiment of Figures 2A-2C, conductive coil 200 may be an omega-shaped flat wire having L-shaped right and left lead portions 210, 220 and semicircular middle portion 230. Those skilled in the art will recognize that right and left lead portions 210, 220 and middle portion 230 may have other shapes suitable for achieving the desired inductive characteristics within the scope of the present invention.

[0026] As shown in the exemplary embodiment of Figures 2A-2C, conductive coil 200 has a bottom side 240 where right and left lead portions 210, 220 are formed, and further has a top side 250, a right side 260, a left side 270, a front side 280, and a back side 290. In one embodiment, back side 290 is preferably a mirror image of front side 280, and left side 270 is preferably a mirror image of right side 260. In one exemplary embodiment, middle portion 230 has right and left extension legs 232, 234 adjacent right and left lead portions 210, 220, respectively. Right and left lead portions 210, 220 preferably have bottom portions 212, 222 and side portions 214, 224, respectively. The bottom portion 212, 222 of each lead 210, 220 is preferably located between one of the left and right extension legs 232, 234 and the side portion 212, 222. These side portions 214, 224 preferably form the terminus of each lead 210, 220. The side portions 214, 224 are preformed to be substantially perpendicular to the bottom portion 212, 222 of each lead 210, 220. While the leads 210, 220 are shown with the side portions 214, 224, those skilled in the art will recognize that the side portions 214, 224 can be omitted and the leads 210, 220 can terminate at the bottom portions 212, 222.

[0027] 1A-1H, each lead portion 210, 220 has a terminal end that is preferably exposed from inductor body 110 and is preferably preformed such that at least a portion of bottom portion 212, 222 of each lead portion 210, 220 is exposed along lead side 120 of inductor body 110 and side portion 214, 224 of each lead portion 210, 220 is exposed along respective left and right sides 140, 150 of inductor body 110. In one embodiment, lead portions 210, 220 are L-shaped and located along lead side 120 and left and right sides 140, 150 of inductor body 110. As used herein, an "L-shape" or "L-shaped" refers to having two leg segments joined at an angle or by a curved member. For example, the bottom portions 212, 222 can extend to the side portions 214, 224 of each lead 210, 220 via a curved segment or at an acute angle.

[0028] As best shown in Figures 1E and 1F, recesses or cutouts 142, 152 can be formed in the left and right sides 140, 150 of the inductor body 110, respectively. The inductor body 110 has a width W3 at the cutouts 142, 152 that is narrower than the maximum width W2 of the inductor body 110. The exposed sides 214, 224 of each lead portion 210, 220 are positioned along the respective cutouts 142, 152, thereby minimizing impact in the width direction of the leads 210, 220. In particular, by positioning the exposed sides 214, 224 of each lead portion 210, 220 along the respective cutouts 142, 152, the maximum width W1 of the conductive coil 200 between the leads 210, 220 can be substantially the same as the maximum width W2 of the inductor body 110. In this configuration, the exposed sides 214, 224 of each lead portion 210, 220 can be substantially aligned with the respective right and left sides 140, 150 of the inductor body 110, thereby minimizing the overall size of the inductor 100. Note that the cutouts 142, 152 are not necessary in all cases, and if these cutouts 142, 152 are not provided, the sides 214, 224 of the lead portions 210, 220 can be formed along the right and left sides 140, 150 of the inductor body 110.

[0029] 1B, 1D, 1F, and 1H illustrate an exemplary embodiment of inductor body 100 with portions in perspective to visualize conductive coil 200 within inductor body 110. The completed inductor 100 of the present invention preferably comprises a formed inductor body 110 that is wrapped around conductive coil 200 and formed, such as by pressing. At least a portion of lead portions 110, 120 are exposed outside inductor body 110 at lead sides 120 and bottom portions of right side 140 and left side 150 of inductor body 110. These lead portions 110, 120 form a significant portion of the bottom side or lead side 120 of inductor 100.

[0030] The length, width, and height of the conductive coil 200 and the inductor body 110 can vary based on the application of the inductor. The dimensions of the conductive coil 200 can be configured to provide a high ratio of usable volume to available space within the inductor body 110.

[0031] 1F , in one embodiment, the vertical height H1 of the conductive coil 200 (height from the bottom side 240 to the top side 250) is substantially equal to or less than the vertical height H2 of the inductor body 110 (height from the lead side to the top side). Because at least a portion of the lead portions 210, 220 of the conductive coil 200 are outside the inductor body 110 within the formed inductor 100, at least a middle portion 230 of the conductive coil 200 can be completely embedded within the inductor body 110 when the conductive coil 200 and the inductor body have substantially the same vertical height. Alternatively, the vertical height H1 of the conductive coil 200 may be >99%, >98%, >95%, >90%, >85%, >75%, >60%, or >50% of the vertical height H2 of the inductor body 110.

[0032] 1E, the maximum width W1 of conductive coil 200 is substantially equal to the maximum width W2 of inductor body 110. Those skilled in the art will recognize that the maximum width W1 of conductive coil 200 or the maximum width W2 of the inductor body may be slightly different without departing from the spirit of the present invention.

[0033] 1H, the depth D1 of conductive coil 200 is preferably less than the depth D2 of inductor body 110. For example, conductive coil 200 may be centered depthwise within inductor body 110, and its depth D1 may be approximately 50% of the depth D2 of inductor body 110. Those skilled in the art will recognize that the maximum width W1 of conductive coil 200 or the depth D1 of the inductor body may be greater than or less than 50% of the depth D2 of inductor body 110 without departing from the spirit of the present invention.

[0034] In a non-limiting example, the maximum dimensions of the finished inductor may be approximately 10 mm (vertical height (H3)) x 10 mm (W2) x 6 mm (depth (D2)). In such an embodiment, the vertical height H1 of conductive coil 200 is approximately 9 mm, and the maximum height H3 of inductor 100 is approximately 10 mm. The maximum width W1 of conductive coil 200 and the maximum width W2 of inductor body 110 are both approximately 10 mm. The depth D1 of conductive coil 200 is approximately 3 mm, and the depth D2 of inductor body 110 is approximately 10 mm. は It is approximately 6 mm. In a preferred embodiment, the inductor has a resistance of less than 0.15 mΩ, an inductance greater than 100 nH, and a temperature rise of 40°C or less at rated currents greater than 100 A. In an embodiment, the current handling capability is in the range of 100-125 A with a temperature rise of 40°C or less.

[0035] Those skilled in the art will recognize that the length, width, and height of the conductive coil 200 and inductor body 110 can vary within the scope of the present invention. Non-limiting examples of inductors according to the present invention include 10 mm (H3) x 10 mm (W2) x 5 mm (D2), 12 mm (H3) x 10 mm (W2) x 5 mm (D2), 7 mm (H3) x 10 mm (W2) x 5 mm (D2), and 5 mm (H3) x 8 mm (W2) x 4 mm (D2).

[0036] In one embodiment, the resistance ranges from 0.01 mΩ to 5.0 mΩ, and the inductance ranges from 10 nH to 1000 nH. Those skilled in the art will recognize that increasing inductance generally results in higher resistance. However, increasing the size of inductor body 110 can increase inductance without increasing resistance.

[0037] FIGS. 8A-8C illustrate an inductor 800 according to another embodiment of the present invention. Generally, inductor 800 is constructed from the same materials as inductor 100 shown in FIGS. 1A-1H. As shown in FIG. 8A, inductor 800 preferably includes an inductor body 100 partially surrounding a preformed conductive coil 820. Inductor 800 differs from inductor 100 shown in FIGS. 1A-1H and conductive coil 200 shown in FIGS. 2A and 2C in that inductor 800 includes conductive coil 820 with a middle portion 830 having different dimensions than the right and left ends that form right and left lead portions 840, 850. As shown in the preferred embodiment of FIGS. 8A and 8B, conductive coil 820 is preferably an omega-shaped flat wire with L-shaped right and left lead portions 840, 850 and semicircular middle portion 830. A middle section 830 of conductive coil 820 is preferably thicker than right and left lead sections 840, 850. The wire thickness tapers gradually in middle section 830 along right and left extension legs 860 and 870. As a result, right and left lead sections 840, 850 preferably have flatter and wider cross-sectional areas than the cross-sectional area of ​​middle section 830, as shown in FIG.

[0038] 8A-8C has flatter and wider lead portions 840, 850, which provides advantages that improve stability, especially when fabricating larger inductors. Additionally, the inductor can be fabricated using a wider inductor body in the depth direction (direction (D) shown in FIG. 1H), thereby adding core material and increasing inductance.

[0039] Furthermore, the wider lead terminations of inductors such as inductor 800 allow for thinner lead terminations for the same cross-sectional area. This results in more free space for core material in the same effective area, while maintaining substantially the same electrical resistance of the lead terminations. Because the size of an inductor is typically determined by the amount of space it occupies on a circuit board, inductors such as inductor 800 according to this embodiment allow for more efficient use of available circuit board space. Furthermore, inductors such as inductor 800 with wider lead terminations allow for more lead surface area on the circuit board, resulting in more secure attachment to the circuit board.

[0040] Wider lead terminations, such as inductor 800, also improve the inductor's ability to handle shock and vibration and improve thermal conductivity between the inductor and the circuit board. Additionally, thinner, wider lead terminations, such as inductor 800, are easier to form or bend.

[0041] Furthermore, those skilled in the art will recognize that an inductor fabricated with the reverse configuration, having a flat, wider midsection and thicker, narrower leads, would also be within the spirit and scope of the present subject matter. An inductor fabricated with a flat, wider midsection and narrower leads can be used to fit within existing circuit board real estate budgets. For example, this may be useful for circuit boards with a predetermined design or layout that accommodates a particular size inductor.

[0042] Figures 9A-9B show an inductor 900 according to another embodiment of the present invention. Generally, inductor 900 is constructed from the same materials as inductor 100 shown in Figures 1A-1H and inductor 800 shown in Figures 8A-8C. As shown in Figure 9A, inductor 900 preferably includes an inductor body 910 that partially surrounds a preformed conductive coil 920. Inductor 900 includes conductive coil 920 that is preferably formed from an omega-shaped flat wire having a middle portion 930 and L-shaped right and left lead portions 940, 950. Similar to the inductor 800 shown in FIGS. 8A-8C, the middle portion 930 of the conductive coil 920 is preferably thicker than the right and left lead portions 940, 950. The thickness of the wire tapers from the middle portion 930 toward the right and left lead portions 940, 950, which preferably result in the right and left lead portions 940, 950 being flatter than the middle portion 930, as shown in FIGS. 9A-9B. The inductor 900 differs from the inductor 800 shown in FIGS. 8A-8C in that the middle portion 930 of the conductive coil 920 has an oval shape, as opposed to a semicircular shape, and the height of the inductor body 910 is greater than its width. For example, but not limited to, the height-to-width ratio may be approximately 1.5:1 or 2:1. Alternatively, in another embodiment (not shown), the middle portion of the conductive coil may have an oval shape, with a smaller height relative to its width.

[0043] 9A and 9B has the advantage that the inductor body 910 can be varied in height and width to accommodate a variety of applications. For inductors such as inductor 900, the size of the inductor can be varied to more efficiently utilize the space available on a circuit board. For example, this is useful when circuit board mounting space is limited but height flexibility is available. Similarly, this is useful when inductor height is a limiting factor but there is more flexibility regarding the inductor width and length.

[0044] FIG. 3 illustrates an exemplary method 300 for manufacturing an inductor according to the present invention. In one embodiment, inductor body 110 can be formed by pressing a magnetic material around a preformed conductive coil 200. Those skilled in the art will appreciate that the inductor manufacturing method illustrated in FIG. 3 and the die set illustrated in FIGS. 4-7 refer to inductor 100 for illustrative purposes only. Those skilled in the art will also appreciate that inductors using preformed conductive coils with different sizes and shapes and inductor bodies with different sizes and shapes are encompassed by the concepts of the manufacturing method and die set illustrated in FIGS. 3-7.

[0045] In step 310, the preformed conductive coil 200, shown in Figures 2A-2C, is preferably seated within a mold assembly 400. An exemplary mold assembly 400 is shown in Figures 6A-6C, including an upper mold portion 410 and a lower mold portion 411. Those skilled in the art will understand that the terms "upper" and "lower" are used as reference points in the drawings, that the lower mold portion 410 can be located on the upper side of the mold assembly 400, and that the upper mold portion 411 can be located on the bottom side of the mold assembly 400, and that the use of single or multiple mold portions is within the scope of the present invention.

[0046] As shown in FIGS. 4A-4C, the lower mold section 410 preferably has a block shape and includes a top side 412, a bottom side 414, a right side 416, a left side 418, a front side 420, and a back side 422. Those skilled in the art will recognize that the lower mold section 410 can have other shapes without departing from the scope of the present invention. The lower mold section 410 also preferably includes one or more seating channels 424. In the exemplary embodiment shown in FIGS. 4A-4C, the lower mold section 410 includes one seating channel 424; however, those skilled in the art will recognize that the lower mold section 410 can include multiple seating channels within the scope of the present invention to improve production efficiency. The seating channel 424 preferably extends from the top side 412 through the lower mold section 410 to the bottom side 414 and is preferably open at both the top side 412 and the bottom side 414. It should be noted that in one embodiment, seating channel 424 may be closed on one side. Bottom mold section 410 may include alignment holes (not shown) for aligning bottom mold section 410 with top mold section 411 during the molding process.

[0047] As shown in FIGS. 4A-4C, the seating channel 424 is bounded by a channel wall 426. Right and left shelves 430, 432 are preferably formed in the channel wall 426 and are preferably positioned to receive the right and left leads 210, 220 of the conductive coil 200. The right and left shelves 430, 432 are preferably complementary in shape to the leads 210, 220. In one embodiment, the right and left shelves 430, 432 are preferably L-shaped to correspond to the L-shaped leads 210, 220 of the conductive coil 200. An intermediate protrusion 434 is formed in the channel wall 426 and is preferably located between the right and left shelves 430, 432. The intermediate protrusion 434 forms the portion of the lead side 110 of the inductor body 110 that is located between the leads 210, 220 of the formed inductor (see FIG. 1A). The seating channel 424 preferably has right and left narrowing walls 436 , 438 in the channel wall 426 that form right and left cutouts 142 , 152 in the inductor body 110 .

[0048] 5A and 5B, the conductive coil 200 is preferably positioned within the seating channel 424 such that the right and left lead portions 210, 220 are seated within the right and left shelves 430, 432 of the seating channel 424 and contact the channel wall 426. The right and left shelves 430, 432, right and left narrowing walls 436, 438, intermediate protrusion 434, and channel wall 426 preferably act together to limit movement of the conductive coil 200 during molding. Additionally, the intermediate protrusion 434 and the right and left lead portions 210, 220 preferably function to form the lead sides 120 of the inductor body 110.

[0049] 6A-6C illustrate an exemplary embodiment of a mold assembly 400 including a lower mold section 410, an upper mold section 411, a lower punch 500, and an upper punch 502. In one embodiment, the upper mold section 411 is preferably block-shaped. Those skilled in the art will recognize that the upper mold section 411 can have other shapes without departing from the scope of the present invention. The upper mold section 411 preferably includes a receiving channel 464. Those skilled in the art will recognize that the upper mold section 411 can include multiple receiving channels 464 corresponding to the number of seating channels 424 in the lower mold section 410. The receiving channel 464 preferably extends from the top side to the bottom side of the upper mold section 411 and is preferably open on both the top and bottom sides. The upper mold section 411 can include an alignment hole (not shown) for aligning with the lower mold section 410 during the molding process.

[0050] Continuing with FIG. 3 , in step 320, magnetic material 504 can be introduced into molding apparatus 400. Preferably, magnetic material 504 is magnetic particles, more preferably powdered or particulate magnetic material, and even more preferably powdered iron particles. Magnetic material 504 is preferably injected into mold apparatus 400 around conductive coil 200. In one embodiment, a portion of magnetic material 504 is pre-compressed or pre-pressed before being added to mold apparatus 400 along with conductive coil 200. Pre-compressed or pre-pressed magnetic material may be used in the initial pressing step, and loose magnetic material 504 may then be added to mold apparatus 400 during the final pressing step.

[0051] In step 330, magnetic material 504 is molded around conductive coil 200 in mold assembly 400. Preferably, magnetic material 504 is pressed by lower and upper punches 500, 502 into inductor body 110 that encases conductive coil 200, except for the exposed portions of right and left leads 210, 220. In the exemplary embodiment shown in FIGS. 6A-6C, lower punch 500 is inserted into seating channel 424 from the bottom side 414 of lower mold section 410, and upper punch 502 is inserted into receiving channel 464 from the top side of upper mold section 411 to press powdered magnetic material around conductive coil 200. FIG. 6B shows mold assembly 400 without magnetic material inserted around conductive coil 200, and FIG. 6C shows mold assembly 400 with magnetic material inserted and pressed around conductive coil 200. Those skilled in the art will recognize that other forms of compacting powdered magnetic material, such as, but not limited to, pressing and injection molding, may be employed without departing from the scope of the method 300.

[0052] 7 shows molded inductor 100 seated in lower mold section 411 after the molding step. After the molding step, magnetic material 504 forms as a composite around conductive coil 200.

[0053] Continuing with Figure 3, after the molding process at step 330 forms inductor 100, molded inductor 100 is cured at step 340, such as by heating in an oven. This curing process bonds the powdered magnetic material into the inductor body. Those skilled in the art will recognize that other forms of curing may be utilized without departing from the scope of the present invention.

[0054] At step 350, the molded inductor 100 is inspected as appropriate, such as by visual inspection and / or electrical properties. The unique configuration of the leads 210, 220 provides a stronger solder connection between the inductor and the circuit board and improves visibility during overhead inspection, such as AOI or X-ray inspection.

[0055] An inductor 100 having a preformed conductive coil 200 according to any of the embodiments described above eliminates the need to weld leads to a lead frame, thereby eliminating the need for weld joints and post-processing cutting of the lead frame. Also, an inductor 100 having a preformed conductive coil 200 according to any of the embodiments described above eliminates the need for post-press lead processing, such as forming and / or bending the leads around the inductor body, which improves inductor manufacturing.

[0056] As described above, lead portions 210, 220 of conductive coil 200 function as an integral part of seating channels 424, 426 during molding. This minimizes the available footprint of inductor 100 while maximizing the available core area within inductor body 110. Furthermore, because conductive coil 200 is within seating channel 466 of mold assembly 200 of the present invention, movement of conductive coil 200 during molding is reduced, allowing conductive coil 200 to be consistently positioned within inductor body 110, preferably within the center of inductor body 110.

[0057] 1A, 1B, 1G, and 1H, the exposed portions of right and left lead portions 210, 220 form a significant portion of lead side 120 of inductor body 110, thereby maximizing solder joint strength and making this inductor ideal for surface mounting. Additionally, sides 214, 224 provide shock and vibration stability to the finished inductor 100.

[0058] The inductor according to any of the embodiments described above can be used in electronics applications with a relatively small footprint, such as surface-mounted and / or server applications, or in other applications with high profile requirements, including DC / DC converters for ultrabooks, notebooks, automotive BLDC motors, and solar inverters. Furthermore, the inverter according to any of the embodiments described above preferably achieves one or more of the following characteristics: a low DC resistance (DCR) of less than 0.15 mΩ, an inductance of more than 100 nH, a DC handling capability in the range of 100 to 125 A in a thin, high-current state, and a low profile, such as a temperature rise of 40°C or less at high currents, that efficiently prevents circuits and / or similar circuits from meeting the current requirements.

[0059] The molded inductor 100 described above provides a simple and cost-effective method for manufacturing consistent quality inductors with minimal waste. Nearly all of the material used to manufacture the inductor 100 can be reused in the finished product. The inductor 100 described above offers significant labor and cost savings over conventional products that require additional labor due to waste parts such as lead frames and wires, and additional labor required after processing due to trimming and forming processes.

[0060] The foregoing description is illustrative only and is not intended to be limiting. Various changes and modifications may be made to the above-described embodiments without departing from the spirit and scope of the present invention. While the present invention has been described in detail, it will be apparent and obvious to those skilled in the art that numerous physical changes, only a few of which have been described in the detailed description of the present invention, may be made without altering the spirit and principles of the present invention. Numerous other embodiments incorporating only a small portion of the preferred embodiment are also possible, without altering the spirit and principles of the present invention. The construction of the embodiments of the present invention and the appropriate configurations for use are in all respects exemplary and / or illustrative and not intended to be limiting. The scope of the present invention is defined not by the foregoing description but by the appended claims, and all alternative embodiments and modifications that come within the meaning and range of equivalency of the claims are intended to be embraced therein. [Explanation of symbols]

[0061] 100 inductor 110 Inductor body 120 Lead side 130 Upper side 140 Right side 142 Notch 150 left side 152 Notch 160 Front side 170 rear side 200 Conductive Coil 210 Right lead 212 Bottom part 214 Side part 220 Left lead 222 Bottom part 224 Side part 230 Middle part 232 Right additional leg 234 Left additional leg 240 bottom side 250 upper side 260 Right side 270 left side 280 Front side 290 rear side 300 Manufacturing method 310 processes 320 processes 330 processes 340 processes 350 processes 400 mold equipment 410 Lower mold part 411 Upper mold part 412 Upper side 414 Bottom side 416 Right side 418 left side 420 Front side 422 Back side 424 Seating Channel 426 Channel Wall 430 Right Shelf 432 Left Shelf 434 Intermediate protrusion 436 Right constriction wall 438 Left constriction wall 464 receiving channel 466 Seating Channel 500 Lower Punch 502 Upper punch 504 Magnetic materials 800 inductor 820 Conductive Coil 830 Middle part 840 Right lead 850 Left lead 860 Right additional leg 870 Left additional leg 900 inductor 910 Inductor body 920 Conductive Coil 930 Middle part 940 Right lead 950 Left lead

Claims

1. a preformed conductive coil having a single curved turn portion connecting first and second base legs extending from symmetrical first and second terminal lead portions, the single curved turn portion being located in a middle portion; a unitary inductor body having a magnetic material molded around a portion of the preformed conductive coil; the integral inductor body has a front surface and an opposite back surface, a top surface and an opposite bottom surface, a first side surface and an opposite second side surface, a height of the integral inductor body extending between the top surface and the bottom surface, a width of the integral inductor body extending between the first side surface and the second side surface, a depth of the integral inductor body extending between the front surface and the back surface, the height of the integral inductor body being greater than the depth of the integral inductor body, and the bottom surface being configured to face a mounting surface of the inductor; at least a portion of each of the symmetrical first and second terminal lead portions of the preformed conductive coil is exposed outside the unitary inductor body along the bottom surface of the unitary inductor body; The first and second base legs extend in a height direction from the bottom surface of the integral inductor body, and the single curved turn portion extends from the first and second base legs to the top surface of the integral inductor body, and the single curved turn portion has a first portion that bends outward from the first base leg toward the first side surface and a second portion that bends outward from the second base leg toward the second side surface. An inductor characterized by:

2. 2. The inductor of claim 1, wherein said magnetic material is molded around a portion of said symmetrical first and second terminal lead portions and said intermediate portion of said conductive coil.

3. The inductor of claim 1 , wherein the middle portion has a circular, semicircular, or oval shape.

4. The inductor of claim 1 , wherein the conductive coil is omega shaped.

5. The inductor of claim 1 , wherein the unitary inductor body is in package form.

6. Each of the symmetrical first and second terminal lead portions further comprises: a bottom having an exposed portion located along the bottom surface of the unitary inductor body; and 6. The inductor of claim 5, further comprising a side portion terminating along a respective one of said first and second sides of said unitary inductor body.

7. each of the first and second side surfaces of the unitary inductor body has a notched portion located on the side of one of the symmetrical first and second terminal lead portions; 7. The inductor of claim 6, wherein a maximum width of said conductive coil between said sides of each of said symmetrical first and second terminal lead portions is substantially the same as a maximum width of said unitary inductor body.

8. 7. The inductor of claim 6, wherein the sides of each of the first and second symmetrical terminal lead portions are preformed to be substantially perpendicular to the bottoms of each of the first and second symmetrical terminal lead portions.

9. 6. The inductor of claim 5, wherein each of the symmetrical first and second terminal lead portions is substantially L- or U-shaped, with a first portion of the L- or U-shape located along the bottom surface of the unitary inductor body and a second portion of the L- or U-shape located along a respective one of the first and second side surfaces of the unitary inductor body.

10. 2. The inductor of claim 1, wherein each of said symmetrical first and second terminal lead portions of said conductive coil has a cross-sectional area that is flatter and wider than the cross-sectional area of ​​said intermediate portion of said conductive coil.

11. The inductor of claim 1 , wherein the magnetic material is a powdered magnetic material.

12. The inductor of claim 1 , wherein said magnetic material is powdered iron particles.

13. 2. The inductor of claim 1, wherein the magnetic material completely surrounds at least the middle portion of the conductive coil.

14. 2. The inductor of claim 1, wherein the preformed conductive coil is formed as a planar member without stacked coil turns.

15. 5. The inductor of claim 4, wherein each of said symmetrical first and second terminal lead portions of said preformed conductive coil is exposed outside said unitary inductor body along a common plane.

16. 2. The inductor of claim 1, wherein a centerline between the first side and the second side is defined in the height direction, and the base leg is located closer to the centerline than the first and second portions of the single curved turn portion of the middle portion.

17. 2. The inductor of claim 1, wherein the width between the first and second portions of the single curved turn of the middle portion is greater than the width between the first and second base legs.

18. providing a formed conductive coil having a single curved turn portion connecting first and second base legs extending from symmetrical first and second terminal lead portions, the single curved turn portion being located in a middle portion; the shaped conductive coil has a top side and a bottom side in a height direction, a first side and a second side in a width direction, and the first and second false legs extend from the bottom side of the shaped conductive coil in the height direction; the single curved turn portion extends from the first and second base legs toward the upper side of the shaped conductive coil, the single curved turn portion having a first portion bending outward from the first base leg toward the first side and a second portion bending outward from the second base leg toward the second side; a magnetic material is molded around at least a middle portion of the molded conductive coil to form a unitary inductor body, and at least a portion of the symmetrical first and second terminal lead portions of the molded conductive coil are exposed outside the unitary inductor body; the unitary inductor body is generally package-like having a bottom side, a top side, a right side, a left side, a front side, and a back side, a height of the unitary inductor body extending between the top side and the bottom side, a depth of the unitary inductor body extending between the front side and the back side, the height of the unitary inductor body being greater than the depth of the unitary inductor body; and The first and second terminal lead portions are exposed along the bottom side of the unitary inductor body.

10. A method for manufacturing an inductor comprising the steps of:

19. 20. The method of claim 18, wherein the symmetrical first and second terminal lead portions are also exposed along a respective one of the first and second sides of the unitary inductor body.

20. 20. The method of claim 19, wherein forming the magnetic material includes placing the formed conductive coil in a die assembly, injecting the magnetic material into the die assembly, and pressing the magnetic material around the formed conductive coil.

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