Electromagnetic device having elements with multiple thicknesses and method for making an electromagnetic device having elements with multiple thicknesses - Patents.com

Abstract

An electromagnetic device is provided having a conductive element and leads having multiple thicknesses. A template for manufacturing an electromagnetic device is provided, formed by extrusion, skiving, swaging, 3D printing or machining. The electromagnetic device having multiple thicknesses has a conductive element having a thicker region and one or more leads having at least one region of reduced thickness that is thinner than the thicker region. An electromagnetic device can be provided having a thicker conductive element housed within a body formed from a core material and a thinner lead or lead portion connected to the conductive element.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application was filed on June 18, 2021, and claims priority to U.S. Patent Application No. 17 / 351,782, which is incorporated herein by reference in its entirety. Field of the Invention

[0002] This application relates to the field of electronic components, and in particular to multi-thickness electromagnetic devices, such as conductive elements and leads for devices such as inductors, and to multi-thickness electromagnetic devices and electromagnetic devices formed using the multi-thickness templates described herein.

[0003] Electromagnetic devices such as inductors are generally passive two-terminal electronic components. An inductor generally consists of a conductor, such as a wire, wound into a coil. When a current flows through the coil, energy is temporarily stored in the magnetic field inside 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 generally formed as having a core body of magnetic material with a conductor therein, such as a wound coil, sometimes formed as a wound coil. Examples of known inductors are disclosed in U.S. Patent Nos. 6,198,375 ("Inductor Coil Construction") and 6,204,744 ("High Current, Low Profile Inductor"), both of which are incorporated herein by reference.

[0005] It is often necessary to create, set or adjust the performance characteristics of an electromagnetic device by changing the characteristics or parameters of some element, such as a wire or coil. Many electromagnetic devices use wound coils formed from conductive materials. The characteristics of such devices can be adjusted by increasing the number of turns in the coil, i.e. by increasing the number of turns in the coil. Thus, specialized machinery and careful adjustments are required.

[0006] When designing electromagnetic devices that require coils formed as laminated or folded layers, additional machining and adjustments are required. Designs that require soldering of different workpieces require additional machining and adjustments and have weaknesses.

[0007] When designing electromagnetic devices with thicker lead portions, there is a possibility that the core body surrounding the lead portions may crack when the lead portions are bent around the core body.

[0008] There is a need for simple, cost-effective methods of manufacturing electromagnetic devices with consistent characteristics, such as inductors with low direct current resistance (DCR).

[0009] There is also a need to manufacture electromagnetic devices, such as inductors, in ways that improve their performance.

[0010] Additionally, there exists a need to manufacture electromagnetic devices such as inductors having conductive elements, such as coils or wires, that are of different sizes but that are not wound or formed from wound pieces of wire. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] U.S. Patent No. 6,198,375 [Patent Document 2] U.S. Patent No. 6,204,744 Summary of the Invention

[0012] Disclosed herein are methods of forming or manufacturing conductive elements and leads having multiple thicknesses, electromagnetic devices having multiple thicknesses.

[0013] As used herein, "multiple-thickness" refers to having one or more thicknesses, at least two different thicknesses, multiple thicknesses, various thicknesses, or multiple different thicknesses. In some embodiments, the thickness can be measured along the length, width, or height of the electromagnetic device or lead frame depending on the orientation of the electromagnetic device or lead frame. As used herein, the term "electromagnetic device having multiple thicknesses" refers to an electromagnetic device having a coil, a conductor or conductive element, and one or more leads, where the coil, conductor or conductive element, and one or more leads have various or different thicknesses, as described in more detail below. For example, the coil and the conductor or conductive element can have a first thickness, one of the leads can have a second thickness, and another of the leads can have a third thickness, where the first thickness is different from the second thickness, and the first thickness is different from the third thickness.

[0014] An electromagnetic device according to one aspect of the invention includes a conductive element formed from a conductive material connected to a first lead and a second lead. The conductive element has a first thickness, the first lead has a second thickness, and the second lead has a third thickness. The first thickness may be different from the second thickness, and the first thickness may be different from the third thickness and may be greater than the second thickness. The first thickness may be greater than the third thickness. The conductive element may take a variety of shapes.

[0015] According to one aspect of the invention, a method of manufacturing an electromagnetic device includes the steps of: providing a conductive material; and forming the conductive material into a conductive element having a first thickness, a first lead portion having a second thickness, and a second lead portion having a third thickness, where the first thickness is greater than the second thickness and the first thickness is greater than the third thickness. The method can further optionally include pressing a body around the conductive element, at least a portion of the first lead, and at least a portion of the second lead.

[0016] A method for making a template for forming an electromagnetic device having multiple thicknesses according to one embodiment of the present invention includes the steps of: providing a conductive material; and forming the conductive material into a template having multiple thicknesses. The template having multiple thicknesses includes a conductive element having a first thickness, a first lead portion having a second thickness, and a second lead portion having a third thickness, the first thickness being greater than the second thickness, and the first thickness being greater than the second thickness. The template can be in the form of a lead frame.

[0017] One aspect of the invention relates to a method of making a template for a multi-thickness electromagnetic device, comprising extruding a conductive material into a multi-thickness metal extrusion or sheet having regions of different thicknesses or heights. The extruded conductive material is a single, continuous or integral piece of conductive material, such as a conductive metal. The thicker region of the extruded conductive material generally corresponds to a central region of the extruded conductive material and is a portion of the extruded conductive material. The thicker region is greater in thickness than the outer or side regions of the central region. The multi-thickness extruded conductive material may be plated with a first layer of nickel and a second or outer layer of tin. The multi-thickness extruded conductive material is stamped to form a multi-thickness template of a desired shape having a conductive element connected to a first lead and a second lead. The stamped multi-thickness template thus has a formed region that may be considered a coil, coil region or wire region, and may be generally referred to herein as a "conductive element." The conductive element generally forms a central or inner region of the template within the thicker region of the template. The conductive element, the first lead, and the second lead are all formed from a single, continuous, or integral piece of conductive material.

[0018] Another aspect of the invention relates to a method for making a multi-thickness template for an electromagnetic device. The method includes providing a metal plate, sheet or strip of conductive material that begins with a uniform thickness or height. The conductive material is a single, continuous or integral piece of conductive material. The conductive material is metal skived or cut using a cutting tool with surfaces of various dimensions, such as a blade having a cutting surface at a first height and at least one non-cutting surface at a lower second height, to form a multi-thickness metal sheet. The conductive material may be plated with nickel as a first layer and tin as a second or outer layer. The conductive material is stamped to form a template of the desired shape of a conductive element connected to a first lead and a second lead. The conductive element corresponding to the thicker regions of the multi-thickness template is of a greater thickness than the outer or side regions of the multi-thickness template and / or leads.

[0019] Another aspect of the invention relates to a method of manufacturing a multi-thickness template for an electromagnetic device, comprising providing a metal plate, sheet or strip of conductive material beginning with a uniform thickness or height. The conductive material is a single, continuous or integral piece of conductive material. The conductive material may be plated with nickel as a first layer and tin as a second or outer layer. The conductive material is stamped to produce a template having conductive elements of a desired shape and leads extending from the conductive material. To produce a multi-thickness template using conductive elements having greater thicknesses in outer or side regions of the conductive material and / or leads, the predetermined outer regions of the template, which may include the leads, are flattened, such as by swaging or pressing. In this configuration, the thickness or height of the predetermined outer region is less than the thickness or height of the conductive elements.

[0020] In one embodiment of the invention, the thickness of the conductive element is less than the thickness of the first lead and / or less than the thickness of the second lead. In this embodiment of the invention, a manufacturing method similar to that described above can be performed, and the thickness of the conductive element can be reduced and the thickness of the first lead or the second lead can be made thicker than the thickness of the conductive element.

[0021] In one aspect of the invention, the templates disclosed herein can be used to form electromagnetic devices.

[0022] In one aspect of the invention, an electromagnetic device can be formed having only one conductive element and lead portion having different thicknesses, in which case no core body or core material is formed around the conductive element or lead portion.

[0023] An electromagnetic device according to one embodiment of the invention may have a magnetic powder, body, or core body compressed and / or molded around the conductive element and portions of the conductive element, e.g., the conductive element and portions of the leads adjacent the conductive element. In this case, the leads may be provided around and folded over an outer surface of the body to form contact points on one outer surface of the body. Preferably, some of the leads are provided along a bottom surface of the body to form surface mount leads. In other embodiments, the leads are not folded in this manner.

[0024] The conductive material may be formed into a conductive element having a particular shape, such as a serpentine shape, or other shapes having folded or curved regions, such as an "S" shape, a circle, an ellipsoid, or an omega (Ω) shape. The conductive element may be generally formed into a rectangular shape on a beam, an "I" shape, an "H" shape, a "barbell" shape, or any other predetermined shape. The body of the electromagnetic device may surround the conductive element and be pressed around the conductive element, with leads extending from a surface or surfaces of the body.

[0025] It is noted that the conductive element of the present invention is formed without the need for multiple layers of wire or coils or windings. In some embodiments of the present invention, a non-wound conductive element is provided that is extruded, stamped, pressed and / or cut from a sheet of metal to form an integral piece with the attached leads. It is preferred that there are no interruptions or breaks in the conductive element along the path from one lead along the conductive element to the other lead. The conductive element is non-wound in shape, such that one portion of the conductive element does not pass above or cross over another portion.

[0026] Also, other conductive materials known in the art, such as other materials used for coils and conductive elements, may be used without departing from the teachings of this invention. Insulation may also be provided around or between portions of the conductive elements and / or leads if necessary for a particular application.

[0027] The lead portions may be aligned along a generally linear path or may lie generally along the same plane and may have a predetermined height and width.

[0028] The leads and conductive elements can be formed simultaneously during the manufacturing process, and the conductive elements do not need to be joined to the leads by welding or the like.

[0029] In accordance with the teachings of the present invention, electromagnetic devices can be formed having multiple thicknesses of conductive material within a single, continuous, or uniform piece.

[0030] Coil regions or conductive elements having a greater thickness function in part to reduce the direct current resistance (DCR) of the inductor.

[0031] The small, thin outer portion (e.g., lead portion) thickness facilitates lead formation. Furthermore, when the lead portion is formed according to an aspect(s) of the present invention, the lead portion has a large solderable surface area, improving the mounting stability of the device and therefore improving shock and vibration resistance. Additionally, the lead portion formed according to the present invention improves heat transfer between the electromagnetic device and the circuit board, such as a printed circuit board (PCB), on which the device is mounted. [Brief description of the drawings]

[0032] The above aspects and many of the attendant advantages of the present invention will become more readily apparent from the following detailed description when taken in conjunction with the accompanying drawings.

[0033] FIG. 1A is an isometric view, partially transparent, of an electromagnetic device according to one embodiment of the present invention.

[0034] FIG. 1B is a top view, partially transparent, of the electromagnetic device according to one embodiment of the present invention shown in FIG. 1A.

[0035] FIG. 1C is a partially transparent side view of the electromagnetic device according to one embodiment of the present invention shown in FIG. 1A.

[0036] FIG. 2A is an isometric view, partially transparent, of an electromagnetic device according to one embodiment of the present invention.

[0037] FIG. 2B is a top view, partially transparent, of the electromagnetic device according to one embodiment of the present invention shown in FIG. 2A.

[0038] FIG. 2C is a partially transparent side view of the electromagnetic device according to one embodiment of the present invention shown in FIG. 2A.

[0039] FIG. 3 is a flow chart illustrating a method for making a multi-thickness template and an electromagnetic device according to one embodiment of the present invention.

[0040] FIG. 4 illustrates a metal sheet formed from a conductive material according to some embodiments of the present invention.

[0041] FIG. 5A illustrates a multi-thickness metal sheet according to one embodiment of the present invention.

[0042] FIG. 5B is a side view of the multi-thickness metal sheet of FIG. 5A.

[0043] FIG. 6 is a diagram illustrating a multi-thickness template according to one embodiment of the present invention.

[0044] FIG. 7 illustrates a multi-thickness template with bodies formed around multiple regions of the template according to one embodiment of the present invention.

[0045] FIG. 8 is a diagram illustrating a template with multiple thicknesses according to one embodiment of the present invention.

[0046] FIG. 9 is a flow chart illustrating a method for making a multi-thickness template and an electromagnetic device according to one embodiment of the present invention.

[0047] FIG. 10 shows a blade skiving a metal sheet to form sheets of multiple thicknesses.

[0048] FIG. 11 is a flow chart illustrating a method for fabricating a multi-thickness template and electromagnetic device according to one embodiment of the invention.

[0049] FIG. 12 is a diagram showing a template according to one embodiment of the present invention.

[0050] FIG. 13 is a detailed view of a multi-thickness template having planarized lead portions according to one embodiment of the present invention.

[0051] FIG. 14 is an isometric view of an electromagnetic device according to one embodiment of the present invention.

[0052] FIG. 15 is an isometric view of an electromagnetic device or template according to one embodiment of the present invention.

[0053] FIG. 16 is a diagram showing a template according to one embodiment of the present invention.

[0054] In the following description, several terms are used for the purpose of explanation only and are 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", "an" and "the" as used in the claims and corresponding parts of the specification are defined as including one or more of the subject element, unless specifically stated to the contrary. This terminology includes the specifically mentioned word, its derivatives and words of similar meaning. The term "at least one" preceding two or more words, such as "A, B, or C", does not mean just any one of A, B or C, but any combination thereof. It should be noted that some of the drawings show partially transparent parts, but all of these are intended for explanation, illustration and demonstration purposes only. Also, these drawings do not show that an element is transparent in its final manufactured form.

[0055] 1A-1C show an example of an electromagnetic device 100 that may be formed in accordance with an embodiment of the present invention and that includes a shaped conductive element 150, which may also be referred to as a "coil" or "coil region." In the embodiment shown in FIGS. 1A-1C, the conductive element 150 includes a serpentine or meandering element, which may be an "S" shaped element, "S-shaped" element, or "S-conductive element," for example, when viewed in the orientation of FIGS. 1A and 1B, or when viewed from above or below. A first curved portion C1 includes a first end 152 (also referred to as a "lead portion") that extends adjacent one of the leads 140a, and a second end 153, the first curved portion C1 curved around the center of the conductive element 150. The second curved portion C2 has a first end 155 extending from another of the leads 140b (also referred to as a "lead portion"), and a second end 154, which curves around the center of the conductive element 150 in an opposite direction from the first curved portion C1. Each curved portion forms an arc that encircles a portion of the center of the conductive element 150. Each curved portion forms along a circumferential path around the central region of the conductive device. A similar configuration of an electromagnetic device is described in U.S. Pat. No. 10,854,367, which is incorporated herein by reference in its entirety. A central portion 151 of the conductive element 150 crosses in a generally diagonal direction and extends between and connects the second end 153 and the second end 154. This central portion preferably passes through the central region of the conductive element. The central portion 151 is generally straight.

[0056] The S-conductive element or "S" shape is illustrative of one embodiment of the present invention. Other configurations are contemplated, including arc-shaped, Z-shaped, or N-shaped conductive elements, as well as curved or straight conductive elements, all of which are within the scope of the present invention. A conductive element configuration that extends along a serpentine path between the leads, with a portion intersecting the midline or center of the conductive element or electromagnetic body, may be considered a "serpentine" conductive element. By way of example and not of limitation, S-shaped, Z-shaped, N-shaped, and other shapes of conductive elements having a serpentine path from one lead to the other may all be considered "serpentine". The shape of the conductive element 150 may be designed to optimize the path length relative to the space within the electromagnetic body while minimizing resistance and maximizing inductance. This space may be designed to provide a high ratio of used space to space within the electromagnetic body. In one embodiment of the invention, conductive element 150 has a top surface that is preferably flat, i.e., oriented essentially in a plane. A serpentine conductive element may be considered a coil or coil region, but is distinct from a "wound" conductive element, which is formed from a wire or piece of conductive material wrapped around and surrounding a central portion or axis of an electromagnetic core.

[0057] As shown in FIGS. 1A-1C, the illustrated electromagnetic device 100 has a length L1 along an X1-X2 axis or X direction, where X1 is a first direction and X2 is a second direction opposite the first direction, a length L2 along a Y1-Y2 axis or Y direction, where Y1 is a third direction and Y2 is a fourth direction opposite the third direction, and a thickness H1 along a Z1-Z2 axis or Z direction, where H1 is a height when viewed from the side as in FIG. 1C, where Z1 is a fifth direction and Z2 is a sixth direction opposite the fifth direction. For ease of understanding, the Z1-Z2 axis will be referred to as the "thickness." Similarly, a region(s) of a conductive element that is thicker or taller may be referred to as a "thicker region."

[0058] In one embodiment of the invention, as shown in FIG. 1C, conductive element 150 has a thicker thickness region 159 that has a first thickness T1 along the Z1-Z2 axis as shown in FIG. 1C that is thicker than the second and third thicknesses T2 and T3 of the conductive material of leads 140a, 140b, etc., having lead portions 156, 157 adjacent outer side ends 174, 175 of conductive element 150. In this configuration, substantially the entire "S"-shaped conductive element 150 has the thicker region 159. However, the portion of the conductive element having the thicker region can be thinner than the entire "S"-shaped conductive element. For example, a conductive element can have thicker and thinner portions, with each of the thicker portions being a thicker region. In this configuration, lead 140a has a thickness T2 along substantially the entire length of lead 140a, and lead 140b has a thickness T3 along substantially the entire length of lead 140a.

[0059] In one embodiment of the invention, as shown in FIGS. 1A-1C, a finished electromagnetic device such as inductor 100 can have a body 133, also referred to as a core body, shown partially transparent, pressed around or otherwise encasing or surrounding the conductive elements and at least a portion of the leads. The body can be formed as a first body portion 110 and a second body portion 120. First body portion 110 and second body portion 120 sandwich, press around or otherwise encase conductive elements 150 and leads 140a, 140b to complete inductor 100. When compressed around the conductive elements and a portion of the leads, first body portion 110 and second body portion 120 become a single, integral compressed body and can be referred to simply as a "body" or a "core body."

[0060] The body 133 may be formed from a magnetic material, such as a ferrous material, and has a top surface 134 and an opposing bottom or bottom surface 135, a first side 136 and an opposing second side 137, a first side 170 adjacent the first lead 140a and an opposing second side 172 adjacent the second lead 140b. The body may be formed from, for example, iron, a metal alloy, and / or ferrite, or a combination thereof, or other materials known in the art and used to form such bodies. The first body portion 110 and the second body portion 120 may be formed from iron powder or a similar material. Other acceptable materials, such as known materials, known in the electromagnetic device art may also be used to form the body or body portions. The body may be made of magnetic molding materials containing iron powder, fillers, resins, lubricants, etc., as disclosed in U.S. Pat. No. 6,198,375 ("Electromagnetic Conductive Element Structures") and U.S. Pat. No. 6,204,744 ("High Current, Low Profile Inductor"), both of which are incorporated herein by reference in their entireties. The body 133 may be made of magnetic materials containing one or more of iron, iron alloys, and / or ferrites, and / or combinations thereof. For example, the body 133 may be made of iron, iron alloys, or ferrites, combinations thereof, or other materials known in the inductor art and used to make such bodies. Materials such as those described in U.S. Pat. Nos. 6,198,375 and 6,204,744, combinations thereof, or other equivalents known in the art, may be used, and are generally referred to as the "core material(s)." Although the first body portion 110 and the second body portion 120 are formed from the same core material using the same forming method, the first body portion 110 and the second body portion 120 may be formed from different core materials using different processes as are known in the art.

[0061] The regions of conductive material between the thicker region T1 of body 133 and the outer sides 170, 172 may be considered to be the beginning or portion of leads 140a and 140b, or may be considered to be transition portions of conductive element 150 of lesser thickness or height that extend between the thicker regions to the sides 170, 172, respectively. For convenience, these regions are referred to as first inner lead portion 156 and second inner lead portion 157. As described below, these portions will be contained within or otherwise surrounded by body 133.

[0062] When first body portion 110 and second body portion 120 surround the conductive element and a portion of the leads and are pressed or overmolded around conductive element 150, a portion of leads 140a, 140b are initially exposed until folded under first body portion 110, as can be seen in the final state shown in the partially transparent embodiment of Figures 1 and 2. In the completed electromagnetic device or "part," a portion of each lead 140a, 140b extends along a side or lateral surface of first body portion 110, as shown in Figures 1A-1C. First lead 140a may terminate in surface mount contact portion 130a, and second lead 140b may terminate in surface mount contact portion 130b, each folded under bottom surface 135 of body 133, which may be first body portion 110, as shown in Figures 1A-1C.

[0063] It should be noted that electromagnetic devices according to embodiments of the invention may be formed without a core body. The leads may be bent to form surface mount terminations. One embodiment is shown in FIG. 14. FIG. 15 shows an electromagnetic device according to embodiments of the invention that may be formed without a core body, with the leads being straight, i.e., unbent, and either extending linearly or at an angle upward from the conductive element. FIGS. 14 and 15 show an embodiment of a completed electromagnetic device that may be constructed with conductive elements and leads having multiple thicknesses, and without the use of core material or a core body surrounding the elements. The electromagnetic device 100' may be constructed with a conductive element 150' having a serpentine shape. A first curved portion C1' has a first end 152' and a second end 153' that extend along one of the leads 140a' (also referred to as the "lead portion"), and the first curved portion C1' curves around the center of the conductive element 150'. The second curved portion C2' has a first end 155' and a second end 154' extending from the other of the leads 140b' (also referred to as the "lead portion"), the second curved portion being opposite the first curved portion C1' and curved around the center of the conductive element 150'. Each curved portion forms an arc around the center of the conductive element 150'. The curved portions may extend along a circumferential path around the central region of the device. The central portion 151' of the conductive element 150' generally crosses diagonally, connects the second end 153' to the second end 154', and may preferably pass through the central region of the conductive element. The central portion 151' is generally straight. The first inner lead portion 156' is adjacent the first end 152', and the second inner lead portion 157' is adjacent the second end 155'. The conductive element 150' has a thicker region 159'. As shown in Figure 15, the leads 140a', 140b' extend linearly outward from the conductive element 150'. The leads 140a', 140b' are bent to form surface mount lead portions 130a', 130b' as shown in Figure 14. As shown in Figure 15, the conductive element 150' has a thicker region having a first thickness portion TH1B that is thicker than a second thickness portion TH2B adjacent the outer end 174', and a third thickness portion TH3B adjacent the outer end 175'.

[0064] Leads 140a, 140b may have the same uniform thickness, or substantially the same uniform thickness, along the entire length of each lead.

[0065] 2A-2C depict another embodiment of the invention, and illustrate one embodiment of an electromagnetic device 200 that may be formed in accordance with one embodiment of the invention, including a shaped conductive element 250. In the device depicted in FIGS. 2A-2C, conductive element 250 may be a substantially linear conductive element configured as an "I" or "H" shaped conductive element, or a "barbell" shaped conductive element when viewed from above as depicted in FIG. 2B. Such a conductive element may also be considered or referred to as a coil. In such a configuration, a central portion 252 of conductive element 250 has a width W1 along the Y1-Y2 axis or Y direction as viewed in FIGS. 2A-2C, a first side 253 has an outer width W2 that is greater than width W1 along the Y1-Y2 axis or Y direction as viewed in FIGS. 2A-2C, and a second side 254 opposite the first side 253 of device 200 and having a width W3 that is greater than width W1 along the Y1-Y2 axis or Y direction as viewed in FIG. W3 may be the same as W2. Conductive element 250 may be generally rectangular between first side 253 and second side 254.

[0066] 2A-2C, one embodiment of the conductive element 250 of the present invention has a thicker region 259 that has a first thickness T1' that is thicker than the second and third thicknesses T2' and T3' of other portions of the conductive material, such as the lead portions including the first and second inner lead portions 255 and 257 adjacent the outer ends 274, 275 of the conductive element 250 along the Z1-Z2 axis or direction as shown in FIG. 2C. In this configuration, substantially the entire "barbell"-shaped conductive element can have the thicker first thickness T1'. The portion of the conductive element with the greater thickness can be smaller than the entire "barbell"-shaped conductive element, and the conductive element 250 is not wrapped around an axis.

[0067] Although a finished electromagnetic device according to the present invention can be formed without a core body as shown in Figures 2A-2C, in one embodiment of the present invention, a finished electromagnetic device 200, such as an inductor, can include a body 233, shown partially transparent, or a core body, which can be pressed into or otherwise encased or surrounded by at least a portion of the conductive element 250 and leads 140a, 240b. A body 233 may be formed having a top surface 234, an opposing bottom surface 235, a first side 236 and an opposing second side 237, and a first side 270 adjacent to first lead 240a (or “lead portion”) and an opposing second side 272 adjacent to second lead 240b (or “lead portion”). The body may be formed as a first body portion 210 and a second body portion 220. First body portion 210 and second body portion 220 sandwich and press around or otherwise contain conductive element 150 and portions of leads 240a and 240b to complete inductor 200. When compressed around the conductive elements and portions of the leads, first body portion 210 and second body portion 220 may be considered a single, unitary compressed body from the core material(s).

[0068] Body portion 210 and second body portion 220 surround the conductive elements and portions of the leads and may be pressed or overmolded around conductive element 250, with the exposed portions of leads 240a and 240b initially remaining exposed until folded under first body portion 210 as shown in the final state of the partially transparent embodiment in FIGS. 2A-2C. In the completed electromagnetic device or "part," each lead 240a and 240b may extend along a side 270, 272 of first body portion 210 as shown in FIGS. 2A-2C. First lead 240a may terminate in a first contact portion 230a, and second lead 240b may terminate in a second contact portion 230b. Each contact portion is folded under a bottom surface 235 of a body 233, such as first body portion 210, as shown in FIGS. 2A-2C.

[0069] Below is described a method of manufacturing an electromagnetic device as illustrated in Figures 1A-2C or 14-16, or a similar electromagnetic device having a multi-thickness element or a multi-thickness template that can be used in forming the electromagnetic device shown in Figures 1A-2C or 14-16, or the like. In some embodiments, the template can be formed as a lead frame.

[0070] In one embodiment of the present invention, a method for manufacturing an electromagnetic device is illustrated by the flow chart in FIG.

[0071] In step 1010, a conductive material is provided. The conductive material may be heated to form a molten conductive material that may be shaped as disclosed herein. Examples of conductive materials include, but are not limited to, copper, steel, aluminum, zinc, bronze, and combinations or alloys thereof. Further examples of conductive materials that may be used include conductive materials in wire form, such as copper wire, aluminum wire, and platinum wire.

[0072] In step 1012, the conductive material is extruded by a metal extrusion process to form a sheet of multiple thicknesses. For example, a heated or molten conductive material is extruded through a shaped opening. The extrusion process involves forcing a near molten or heated conductive material, such as a metal, through a die having a desired profile or shape. FIGS. 5A and 5B show a sheet of multiple thicknesses 310. The sheet has a central region 312 having a thick region 314 with a first thickness TH1, a first outer portion 316 adjacent a first side 318 of the thicker region 314 with a second thickness TH2 less than the thickness TH1, and a second outer portion 320 adjacent a second side 329 of the thicker region 314 with a third thickness TH3 less than the thickness TH1. As shown, the first outer portion 316 and the second outer portion 320 may be on opposite sides of the thicker region 314. As described below, multiple thickness sheets 310 are used to form a template.

[0073] The multiple thickness sheets 310 may be plated with a first layer of nickel and a second layer of tin over the nickel using electroplating or a similar process at step 1014. Known plating methods may be used to form the nickel and tin layers, which improve solderability.

[0074] In step 1016, the multi-thickness sheet 310 is stamped or otherwise machined or formed to form a multi-thickness template 322 for use in an electromagnetic device as shown in FIGS. 1A-1C. FIG. 6 shows a multi-thickness template 322 having conductive elements 150 in the configuration shown in FIGS. 1A-1C. It is noted that various shapes of conductive elements can be formed without departing from the teachings herein. When stamped or otherwise machined, the template 322 has thicker regions that correspond to the thicker regions 314 of the multi-thickness sheet 310 used to form the template 322, the thicker regions 314 having the greater thickness TH1. The conductive elements 150 may be located in a central or inner region of the template.

[0075] Although one or more conductive elements are illustrated in Figure 6, the template may be provided for a single conductive element, and any number of conductive elements greater than or equal to two may be provided on the template.

[0076] It should be noted that steps 1014 and 1016 may be performed in any order. For example, multi-thickness sheet 310 may be formed into multi-thickness sheet 322 according to step 1016 and then plated according to step 1014.

[0077] As shown in FIG. 6, the template 322 has the leads 140a, 140b connected to the conductive element 150, and the area forming the leads 140a, 140b corresponds to a first outer portion 316 having a thickness TH2 and a second outer portion 320a having a third thickness TH3. Thus, the thickness of each of the leads 140a, 140b is less than the thicker TH1 of the conductive element 150. The presence of the first inner lead portion 156 and the second inner lead portion 157 adjacent to the conductive element 150 facilitates the formation of the leads, such as by bending. The small thickness of the leads facilitates the bending process and facilitates the formation of the surface mount leads without cracking or bursting. As shown in FIG. 1B and FIG. 6, the leads 140a, 140b have a width along the Y1-Y2 axis or Y direction, which may be less than the width of the conductive element 150.

[0078] For example, as illustrated in Figures 1A-1C and 6, the first inner lead portion 156 of the first lead 140a and the second inner portion 157 of the second lead 140b have a width (along the Y1-Y2 axis or direction) that may be narrower or smaller than the widths of other portions of the leads 140a, 140b, such as the first surface mount contact portion 130a and the second surface mount contact portion 130b.

[0079] The upper surface of the conductive element 150 can be formed to lie substantially in or along a plane. The lower surface of the conductive element 150 can be formed to lie substantially in or along a plane. The upper or lower surface of the conductive element can be generally flat.

[0080] The leads 140a, 140b can be formed with upper or lower surfaces that lie substantially in or along a plane. The upper or lower surfaces of the leads 140a, 140b can be generally flat.

[0081] 6, the template 322 is formed as a lead frame and has at least first and second carrier strips 324, 326 on opposing outer sides of the lead frame 322. The carrier strips 324, 326 may have progressive holes 328 used for alignment when connecting to a manufacturing device. Therefore, the carrier strips 324, 326 may be considered as members to be used as appropriate.

[0082] It should be noted that the conductive element 150 and leads 140a, 140b, and carrier strips 324, 326, if used, are all formed from a unitary piece of conductive material that is preformed to a thickness greater than the thickness of the leads 140a, 140b. The conductive element 150 is formed into a predetermined shape and does not require wrapping or bending of metal strip or wire. No portion of the conductive element 150 crosses over or under another portion of the conductive element 150. The inductance of an electromagnetic device made as described herein can be adjusted, for example, by changing the thickness, width, shape or other dimensions of the conductive element, by changing the core material, by increasing or decreasing the thickness of the core material, by changing the density of the core material, such as by hot or cold pressing, and / or by changing the position of the conductive element within the core body.

[0083] 15 can also be seen as a template for an electromagnetic device by, for example, trimming or bending leads 140a', 140b'. In this example, the template would be formed by stamping multiple thicknesses of conductive material into the shapes shown in FIG.

[0084] At step 1018, if the device has a core body, one or more core materials, preferably iron and / or ferrite powder, are pressed around the conductive element 150 and a portion of the leads 140a, 140b, including the first and second inner lead portions 156, 157, to form the body 133. The body 133 is formed by inserting a plated template 322 into a compression press and pressing the one or more core materials into the coil portion of a lead frame of the desired shape, such as a generally rectangular shape, although as shown the shape may also be rounded corners or edges. FIG. 7 shows the template 322 with the body 133, with the body 133 partially transparent, to show the body formed around the conductive element 150 and a portion of the leads 140a, 140b. It is noted that step 1018 is optional if the electromagnetic device is formed without a core body.

[0085] In step 1020, the portions of the template adjacent the leads are trimmed to size and applied around the body 133 to form surface mount leads as desired for current circuit board assembly processes. At least a portion of each of the leads 140a, 140b is applied along a side of the body 133, and at least end portions 130 of the leads 140a, 140b are bent under and applied along the bottom surface 135 of the body 133. As previously discussed, an example of a completed electromagnetic device 100 is shown in FIG. 1A.

[0086] Figure 8 illustrates a template 330 formed according to the process illustrated in Figure 3 and corresponding to an electromagnetic device having conductive elements 250 as shown in Figures 2A-2C. As shown in Figure 8, the conductive elements 250 of template 330 have linear conductive elements, such as "I" or "H" shaped conductive elements, or conductive elements that have a "barbell" shape when viewed from above. The template may be formed according to the process outlined in Figure 3 and described above. At step 1016, conductive elements 250 have the predetermined shape illustrated in Figures 2A-2C.

[0087] As shown in FIG. 8, the template 330 includes the conductive element 250 as well as the leads 240a, 240b. When the template 330 is formed as a lead frame, for example, carrier strips 332, 334 may be provided. The conductive element 250 and the leads 240a, 240b are both formed from the same unitary piece of conductive material. The carrier strips 332, 334 may include progressive holes 336 for alignment purposes when connected to a manufacturing tool. The conductive element 250 may include a region 280 having a thicker region with a thickness TH1a. The first lead 240a has a thickness TH2a and the second lead 240b has a thickness TH3a. Thus, the thickness of each of the leads 240a, 240b is less than the thicker thickness TH1a of the conductive element 150. The first inner lead portion 255 and the second inner lead portion 257 adjacent the conductive element 150 have a thinner thickness, which may facilitate forming the leads, such as by bending them. Because the leads have a smaller thickness, these regions can bend more easily to form surface mount leads without cracking or breaking. As illustrated in Figures 2B and 8, the width (along the Y1-Y2 axis or Y direction) of the first inner lead portion 255 and the second inner lead portion 257 may be narrower or smaller than the width of other portions of the leads 240a, 240b, such as the first surface mount contact portion 230a or the second surface mount contact portion 230b.

[0088] Skiving or cutting processes can also be used to manufacture electromagnetic devices according to aspects of the invention. Skiving uses a cutting blade to skim off material.

[0089] A method for making an electromagnetic device according to one embodiment of the present invention is described with reference to the flow chart of FIG. 9. In step 2010, a sheet of conductive material is used as a starting material that can be formed from the conductive material by rolling, pressing, or the like. FIG. 4 illustrates a sheet 300 formed from a conductive material. The term "sheet" as used herein is intended to encompass the concept of a sheet, plate, or strip of pieces of conductive material that can be used as a starting material to form the template of the present invention. The sheet 300 of conductive material is preferably a metal sheet such as copper. Examples of conductive materials that can be used to form the sheet 300 include, but are not limited to, copper, steel, aluminum, zinc, bronze, and combinations or alloys thereof. The thickness of the metal sheet may be selected to be the thickness of the thicker regions of the conductive element that will be formed from the sheet. Additionally, the conductive material can be formed or provided as, or start from, a rod, wire, or the like that can be processed or formed according to the teachings herein without departing from the scope of the present invention. Thus, although a sheet is illustrated, other conductive materials with other shapes can be used to form the electromagnetic devices shown and disclosed herein.

[0090] In step 2012, a skiving process is performed to form the sheet using a blade to form a sheet 410 with multiple thicknesses.

[0091] FIG. 10 illustrates a cutting blade 437 having a convex central cut portion 439 that is in the process of cutting a sheet of conductive material to form a multi-thickness sheet 410. The resulting multi-thickness sheet 410 has a central region 412 as a thicker region, a first outer portion 416 adjacent a first side 418 of the greater region 414 having a second thickness less than the thickness of the central region 412, and a second outer portion 420 adjacent a second side 422 of the greater region 414 having a third thickness less than the thickness of the central region but which may be equal to the thickness of the first outer portion 416. As shown, the first outer portion 416 and the second outer portion 420 may be on opposite sides of the greater region 414. The multi-thickness sheet 410 is used to form a template as described below.

[0092] At step 2014, the multiple thickness sheets are plated using electroplating or a similar process to form a first layer of nickel and a second layer of tin over the nickel.

[0093] In step 2016, the multi-thickness sheet 410 is stamped or otherwise machined to form a multi-thickness template for use in an electromagnetic device such as that shown in Figures 1A-1C. This step results in a multi-thickness template as shown in Figure 6.

[0094] In step 2018, one or more core materials, preferably having iron powder and / or ferrite powder, are pressed around the conductive elements and the portion of the leads having the first and second inner lead portions to form a body. In this step, a body 133 is formed around a portion of the template, as described with reference to Figure 7. Step 2018 may be performed optionally if a core body is not desired.

[0095] At step 2020, portions of the template adjacent the leads are trimmed to size and fitted around the body to form surface mount leads as desired for current circuit board assembly processes. At least a portion of each of the leads is fitted along a side of the body and at least an end portion of the leads is bent under and fitted along a bottom surface of the body. As previously discussed, an example of a completed electromagnetic device 100 is shown in FIG. 1A.

[0096] Skiving can also be used to form electromagnetic designs having the configurations shown in Figures 2A-2C. The skiving process can also be used to form conductive elements having various shapes, sizes, orientations, and / or configurations.

[0097] Swaging and / or pressing and / or flattening processes may also be used to form electromagnetic devices according to embodiments of the present invention.

[0098] A method for manufacturing an electromagnetic device according to one embodiment of the present invention is described according to the flow chart of Figure 11. A sheet of conductive material is used as a starting material in step 3010. Sheet 300 shown in Figure 4 is an exemplary sheet of conductive material.

[0099] At step 3012, the sheet is plated using electroplating or a similar process to form a first layer of nickel and a second layer of tin over the nickel. At this plating stage, the sheet is uniform in thickness, which will be greater than the thickness of the conductive elements, as described below.

[0100] At step 3014, stamping or other machining is performed to form a template of uniform thickness.

[0101] 12 shows the template 500 in the process of being formed. The template has a shaped conductive element 520, a first lead 530a and a second lead 530b, all formed from a unitary piece of the same conductive material forming a sheet. If the template 500 is formed as a lead frame, it may have carrier strips 540, 542. The carrier strips 540, 542 may have progressive holes 544 for alignment when connected to manufacturing equipment.

[0102] To obtain a template with multiple thicknesses in step 3016, the first lead 530a and the second lead 530b, or portions of each of them, are flattened, such as by swaging or pressing.

[0103] 13 is a detailed view of a portion of the template 500. The first lead 530a and the second lead 530b are flattened or compressed, thereby giving them a thickness that is less than the thickness of the conductive element 520. Different processes such as stamping, coining, roll forming, or milling can be used to form the reduced thickness portions.

[0104] Upon planarization of the first lead 530a and the second lead 530b, the template 500 has a conductive element 520 with a central region 512 formed as a thicker region 514 having the thickness of the original sheet, the first lead 530a having a thickness less than the thickness of the central region 512, and the second lead 530b having a minor thickness less than the thickness of the central region 512 but which may be the same thickness as the first lead 530a. If these regions are not planarized, the carrier strips 540, 542 may be the same thickness as the conductive element 520.

[0105] In step 3018, one or more core materials, preferably having iron and / or ferrite powders, are pressed around conductive element 520 and a portion of leads 530a, 530b to form body 546. Body 546 is formed by inserting plated template 500 into a compression press and pressing one or more core materials into the coil portion of a lead frame of the desired shape, such as a generally rectangular shape. At this stage, the lead body and frame are configured similarly to FIG. 7 as described above. If a core body is not desired, step 3018 is an optional step.

[0106] At step 3020, portions of the template adjacent the leads are trimmed to size and placed around the periphery of body 546 to form surface mount leads as desired for current circuit board assembly processes. At least a portion of each of leads 530a, 530b is placed along a side of body 133, and at least end portions of leads 530a, 530b are bent under and placed along a portion of the bottom surface of body 546.

[0107] Furthermore, the process shown in Figure 11 can be used to form a template having conductive elements with linear conductive elements that are "I" or "H" shaped conductive elements, or conductive elements that are "barbell" shaped when viewed from above, as shown in Figures 2A to 2C, etc.

[0108] Additionally, to form conductive elements having thicker regions, one can start with a template of generally uniform thickness, as shown in FIG. 12, and plate it up over conductive element 520. For example, copper can be plated all over the conductive element until a consistent thickness is achieved. This "build up" process can be accomplished, for example, by 3D printing a plating material or by depositing metal onto conductive element 520 by methods known in the metal processing arts (e.g., sputtering).

[0109] Additionally, the methods disclosed herein can be used to form electromagnetic devices having shaped conductive elements that are less than the thickness of one or more leads. For example, referring to FIG. 3, step 1012 can be used to extrude a sheet having multiple thicknesses, with a thinner center portion of the sheet and thicker outer portions of the sheet than the center portion. Continuing with FIG. 9, step 2012 can be used to skive a sheet having multiple thicknesses, with a thinner center portion of the sheet and thicker outer portions of the sheet than the center portion. Continuing with FIG. 11, step 3016 can be used to flatten the conductive elements rather than the leads to form conductive elements that are less thick than the leads.

[0110] Thus, as illustrated in FIG. 16, template 700 is stamped from a piece of conductive material having a uniform thickness, such as the sheet shown in FIG. 4. A conductive element 750, which may be a serpentine conductive element, first lead 740a, and second lead 740b, all formed from the same piece of conductive material, is stamped or otherwise formed. In this embodiment, conductive element 750 is stamped, pressed, swaged, or skived to form an electromagnetic device having a thinner thickness of conductive material than leads 740a, 740b. Conductive element 750 may have a serpentine, barbell, or other predetermined shape, and may be generally flat with one or more surfaces lying in or along a plane. Leads 740a, 740b may be folded or trimmed as known or described herein. A core body may be molded around conductive element 750 and a portion of the leads.

[0111] The conductive material or sheet of conductive material may be formed such that the area used to form the conductive element has a different hardness than the area used to form the first and second lead portions. For example, the first portion of the conductive material may have a first hardness (e.g., semi-hard) and the second portion of the conductive material may have a second hardness (e.g., softness similar to that of annealing). Alternatively, the first portion of the conductive material may have a first hardness (Vickers hardness 100 HV10) and the second portion of the conductive material may have a second hardness (Vickers hardness 30 HV10).

[0112] It is to be noted that the surfaces of the conductive elements and / or leads disclosed herein may be slightly rounded, arcuate, or curved, and the side edges may be rounded, arcuate, or curved, depending on the processing method used to form the conductive elements. Acceptable metals used to form the conductive elements and leads include copper, aluminum, platinum, and other metals used as electromagnetic conductive elements as known in the art. As used herein, "flat" means "generally flat"; that is, within normal manufacturing tolerances. It is to be noted that the surfaces of the conductive elements and / or leads disclosed herein may be slightly rounded, arcuate, curved, or corrugated, and the side edges may be slightly rounded, arcuate, curved, or corrugated, depending on the processing method used, and all of these may be considered "flat."

[0113] The thickened portions or regions of the conductive elements described herein act to reduce the direct current resistance (DCR) of an electromagnetic device, such as an inductor, that includes such conductive elements.

[0114] The templates described herein provide multiple thicknesses in a single, integral piece. The templates described herein can also be formed by 3D printing techniques.

[0115] The leads or lead portions of the template have areas of reduced thickness, making it easier to form the leads, for example, by molding and / or bending operations, etc. Additionally, the thinner and wider lead portions not only improve thermal transfer when mounted to a circuit board, but also improve mounting strength and resistance to shock and vibration due to the width of the surface mount leads or terminations.

[0116] It should be noted that the above description is illustrative only and not limiting, and that changes and modifications may be made to the described embodiments without departing from the spirit and scope of the present invention. Although the present invention has been described in detail, it should be clear to those skilled in the art that many physical changes, only some of which are described in the detailed description of the invention, can be made without changing the inventive concepts and principles of the described embodiments. Also, many embodiments are possible, including only a small portion of the preferred embodiments, none of which change the inventive concepts and principles of these portions. The configuration of the embodiments of the present invention and the configurations that may be appropriately adopted are intended to be illustrative in all respects and not limiting. The scope of the invention is defined by the claims, not the above description, and all alternative embodiments and modifications to the embodiments that come within the meaning and scope of this scope are intended to be embraced by the present invention.

Claims

1. providing a conductive material; forming the conductive material into a multi-thickness sheet by extruding, skiving, or flattening, the multi-thickness sheet having a first portion having a first thickness, a second portion having a second thickness, and a third portion having a third thickness; forming the first portion of the sheet having multiple thicknesses into a conductive element, forming the second portion of the sheet having multiple thicknesses into a first lead portion, and further forming the third portion of the sheet having multiple thicknesses into a second lead portion to form a template having multiple thicknesses; having the first thickness is greater than the second thickness; and The first thickness is greater than the third thickness.

13. A method for manufacturing an electromagnetic device having multiple thicknesses.

2. The method of claim 1 , wherein at least a portion of the template having multiple thicknesses is formed by stamping the sheet having multiple thicknesses.

3. 2. The method of claim 1, wherein the conductive element has a serpentine shape, a rectangular shape, an I-shape, an H-shape, or a barbell shape.

4. The method of claim 1 , wherein the conductive element, first lead portion, and second lead portion are formed from a continuous, unwound piece of conductive material.

5. The method of claim 1 , wherein no portion of the conductive element crosses over or under another portion of the conductive element.

6. 2. The method of claim 1, wherein the first lead portion has a uniform thickness along substantially the entire length of the first lead portion, and the second lead portion has a uniform thickness along substantially the entire length of the second lead portion.

7. 2. The method of claim 1, wherein the first lead portion has a first width adjacent the conductive element and a second width at an end of the first lead portion, the second width being different than the first width.

8. 2. The method of claim 1, wherein said second lead portion has a first width adjacent said conductive element and a second width at an end of said second lead portion, said second width being greater than said first width.

9. providing a conductive material; forming the conductive material into a sheet having a plurality of thicknesses, the sheet having a first portion forming a conductive element having a first thickness, a second portion forming a first lead portion having a second thickness, and a third portion forming a second lead portion having a third thickness, the first thickness being greater than the second thickness, and the first thickness being greater than the third thickness; forming the first portion of the sheet having multiple thicknesses into the conductive element, forming the second portion of the sheet having multiple thicknesses into the first lead portion, and forming the third portion of the sheet having multiple thicknesses into the second lead portion to form a template having multiple thicknesses; having pressing a core material around the conductive element, at least a portion of the first lead portion, and at least a portion of the second lead portion to form a body; 2. A method for manufacturing an electromagnetic device comprising the steps of:

10. The method of claim 9 further comprising the steps of trimming the first lead portion and trimming the second lead portion.

11. 11. The method of claim 10, further comprising the steps of positioning at least a portion of the first lead portion along an outer surface of the body and extending at least a portion of the first lead portion along a bottom surface of the body, and further comprising the steps of positioning at least a portion of the second lead portion along the outer surface of the body and extending at least a portion of the second lead portion along a bottom surface of the body.

12. The method of claim 9 , wherein forming the conductive material into a sheet having multiple thicknesses comprises extrusion.

13. The method of claim 9, wherein forming the conductive material into a sheet having multiple thicknesses comprises skiving.

14. The method of claim 9 , wherein forming the conductive material into a sheet having multiple thicknesses includes flattening.

15. A manufacturing method as described in claim 9, wherein the conductive element, the first lead portion, and the second lead portion are formed in a process of forming a template having multiple thicknesses by stamping a sheet having the multiple thicknesses.

16. 10. The method of claim 9, wherein the conductive element has a serpentine shape, a rectangular shape, an I-shape, an H-shape, or a barbell shape.

17. The method of claim 9 , wherein the conductive element, first lead portion, and second lead portion are formed from a continuous, unwound piece of conductive material.

18. 10. The method of claim 9, wherein no portion of the conductive element crosses over or under another portion of the conductive element.

19. 10. The method of claim 9, further comprising plating said multi-thickness sheet or said multi-thickness template with a layer of nickel or tin.

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