Coil and Method for Producing A Coil

Abstract

In an embodiment a coil includes a tube comprising a tube wall composed of an electrically conductive material, wherein the tube wall has an inductive portion in which a gap is arranged that shapes the tube wall so the tube wall forms a helix in the inductive portion, and wherein the tube wall has two contact portions, each contact portion forming an electrical terminal.

Claims

1.-20. (canceled)

21. A coil comprising: a tube comprising a tube wall composed of an electrically conductive material, wherein the tube wall has an inductive portion in which a gap is arranged that shapes the tube wall so the tube wall forms a helix in the inductive portion, and wherein the tube wall has two contact portions, each contact portion forming an electrical terminal.

22. The coil according to claim 21, further comprising a core.

23. The coil according to claim 21, wherein the tube is embedded in a plastic.

24. The coil according to claim 23, wherein the plastic is mixed with magnetic powder, magnetic particles or another magnetic material.

25. The coil according to claim 21, wherein the coil has an E-shaped pot (EP) core.

26. The coil according to claim 21, wherein the tube has an outer diameter of between 0.2 mm and 50 mm, inclusive.

27. The coil according to claim 21, wherein each contact portion has a flat surface forming a solderable terminal.

28. A module comprising: at least two coils according to claim 21, wherein the two coils are arranged in a common housing.

29. A method for producing a coil, the method comprising: providing a tube comprising a tube wall composed of an electrically conductive material, creating a gap in an inductive portion of the tube, wherein the gap forms a helix in the tube wall in the inductive portion; and shaping at least two portions in the tube wall thereby forming contact portions.

30. The method according to claim 29, wherein a laser process is used to create the gap and to shape the contact portions.

31. The method according to claim 29, wherein a recess is formed in the contact portion of the tube by removing a region of the tube wall.

32. The method according to claim 31, wherein the recess in the contact portion of the tube and the gap in the inductive portion are created jointly in a single step.

33. The method according to claim 31, further comprising planarizing a region in the contact portion of the tube wall that was not removed.

34. The method according to claim 29, wherein creating a gap comprises: firstly creating a coil string so that a plurality of inductive portions are arranged along the tube and so that a gap is created in each inductive portion thereby forming a helix in the tube wall in the respective inductive portion, and secondly singulating the coil string between two adjacent inductive portions in each case so that a contact portion is formed that forms an electrical terminal to the two adjacent inductive portions.

35. The method according to claim 34, wherein the coil has an E-shaped pot (EP) core.

36. The method according to claim 34, further comprising creating a plurality of coil strings, and embedding a plurality of coil strings in a plastic, wherein the coil strings are arranged parallel to each other.

37. The method according to claim 36, wherein cores arranged in the coil strings.

38. The method according to claim 36, wherein the plastic is mixed with magnetic powder, magnetic particles or another magnetic material.

39. The method according to claim 36, further comprising singulating the coil strings transversely and/or parallel with respect to a central axis of the coil strings.

40. A method for producing modules, wherein each module has at least two coils in a common housing, wherein each of the coils has a tube comprising a tube wall composed of an electrically conductive material, wherein the tube has an inductive portion in which a gap is arranged that shapes the tube wall to form a helix, and wherein the tube has a contact portion in which the tube wall forms an electrical terminal, the method comprising: creating at least two coil strings comprising a plurality of inductive portions in each of which a gap is created that shapes the tube wall in the respective inductive portion to form a helix, and a contact portion between two adjacent inductive portions in each case; arranging the coil strings in parallel; embedding the coil strings in a plastic, which forms the housing; and singulating the coil strings connected by the plastic, along separation lines that run transverse to a central axis of the coil strings to form the modules, wherein the contact portion, following singulation of the coil string, forms an electrical terminal to the two adjacent inductive portions in each case.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The invention is described in greater detail in the following on the basis of schematic representations of exemplary embodiments.

[0044] FIG. 1a shows a three-dimensional representation of a possible embodiment of a tube;

[0045] FIG. 1b shows a three-dimensional representation of a possible second embodiment of a tube;

[0046] FIG. 2 shows a three-dimensional representation of a coil string;

[0047] FIG. 3 shows a three-dimensional representation of an intermediate product in the production of a coil from the coil string;

[0048] FIG. 4 shows a three-dimensional representation of a coil, the contact portions of which are open and planarized;

[0049] FIG. 5 shows a three-dimensional representation of a coil as in FIG. 4, but which has a magnetic core—cylinder core—and is embedded in plastic;

[0050] FIG. 6 shows a three-dimensional representation of a core that is arranged in a removable housing, having an integrated core—EP core;

[0051] FIG. 7 shows a three-dimensional representation of a plurality of coil strings, which are embedded in plastic to form a package;

[0052] FIG. 8 shows a three-dimensional representation of a plurality of coils, which are embedded in plastic and have been singulated transversely with respect to the central axis of the coil strings; and

[0053] FIG. 9 shows a three-dimensional representation of a coil that has been embedded in plastic and is a single component ready for use.

[0054] In the figures, elements that are the same, similar or visually the same are denoted by the same references. The figures, and the proportions in the figures, are not true to scale.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0055] Shown in FIGS. 1a and 1b is a tube 2 having, respectively, a round and a rounded square cross-sectional area. A tube 2 is an elongate hollow body, having an opening extending from a first end of the body, through the entire body, to a second end that is opposite to the first end. The tube 2 may be symmetrical relative to its central axis 3, the central axis 3 extending from the mid-point of the base area at the first end to the mid-point of the base area of the second end. In one embodiment, the tube 2 may have a circular, oval, rectangular or polygonal cross-sectional area. Other cross-sections are also possible.

[0056] The tube 2 may have an outer diameter of 0.2 to 50 mm. Preferably, the outer diameter of the tube 2 may be in the region of between 0.5 and 20 mm. This size is particularly suitable for producing coils that are suitable for applications on a printed circuit board. The tube wall 6, the thickness of which is determined by the distance between the inner radius to the outer radius of the tube 2, can vary greatly depending on the tube 2 used, although a thickness of less than 1 mm can be advantageous for machining. The circumferential surface 5 of the tube 2 extends along the outer radius, in the direction of the central axis 3. The tube 2 is composed of a primarily electrically conductive material.

[0057] The tube 2 constitutes a starting material that is used in the manufacture of a coil. The method for manufacturing the coil is explained with reference to FIGS. 1 to 3, which show intermediate products in the production of the coil. FIG. 4 and FIGS. 5, 6, 8 and 9 show possible embodiments of the coil 1.

[0058] In the course of the production process, the tube 2 shown in FIG. 1a can first be structured to form a coil string. The coil string is shown in FIG. 2. The tube 2 in this case may be structured, in particular, by a laser process, in which inductive portions 7 and contact portions 8 are realized in the tube 2. The inductive portions 7 and the contact portions 8 alternate along the tube 2.

[0059] A gap 4, which extends through a tube wall 6 and shapes the tube wall 6 to form a helix, is created in the inductive portions 7. An inductance of the inductive portions 7 is thereby realized. Following singulation of the coil string, the contact portions 8 form electrical terminals. A recess is formed in the contact portions 8 during the structuring of the tube 2, a part of the tube wall 6 being removed.

[0060] The coil string optimizes the handling of the coils in production process. Thus, a plurality of coils can be processed simultaneously, resulting in a reduced production cycle time. In addition, material can be saved by the creation of a plurality of inductive portions 7 in one tube 2.

[0061] The inductive portions 7 are integrally connected to each other by the contact portions 8 and have no unnecessary transition resistances between each other.

[0062] The different inductive portions 7 of the coil string may have differing or the same inductances. It is thus possible to create differing coils from one tube 2, each of which can be varied in inductance, and which are therefore suitable for a wide variety of applications. The inductances may be varied, for example, by the number of turns formed by means of the gap 4, or by the distance of the gaps 4 in the direction of the central axis 3 after one passage around the tube 2, which corresponds to the width of the turns. In the exemplary embodiment from FIG. 2, the gaps 4 shown are equal, and consequently the inductance of each inductive portion 7 is also equal.

[0063] FIG. 3 shows a three-dimensional representation of an intermediate product in the production of a coil from the coil string. The coil string has been singulated along separation lines running transversely with respect to the central axis 3 of the coil string.

[0064] The coil has a tube 2 composed of electrically conductive material, with a gap 4 created along a circumferential surface 5 and around the longitudinal axis 3 of the tube 2, thus forming an inductive portion 7. In an alternative embodiment, the entire tube 2 may be structured in such a manner as to provide only a single inductive portion 7 and two contact portions 8 adjoining the latter. Accordingly, the tube 2 may be structured to form the intermediate product shown in FIG. 3, in which case the tube 2 must be cut to a suitable length.

[0065] The contact portion 8 and the inductive portion 7 are connected to each other by a connecting portion 10. The contact portion 8, the connecting portion 10 and the inductive portion 7 are formed integrally and as a single piece from the structured tube wall 6. The connecting portion 10 is of sufficient width so as to be insignificant to the resistance of the coil 1.

[0066] FIG. 4 shows the coil 1 following planarization of the contact portions. The contact portions 8 of the tube 2, which are located between the inductive portions 7, have been planarized. Planarization of the contact portions 8 creates an electrical terminal, as a flat surface, that is suitable for providing electrical contacting. The embodiment shown in FIG. 4 is suitable, for example, for contacting to the printed conductors of a printed circuit board by means of a soldering process.

[0067] However, the design of the contact portions 8 is not limited to the embodiments represented. In particular, the shape of the contact portions 8 may be adapted to a housing shape.

[0068] FIG. 5 shows the coil 1 shown in FIG. 4, which has additionally been equipped with a magnetic core 11. In addition, the coil 1 is embedded in plastic 9, and the plastic 9 may contain amounts of magnetic particles. The use of a, for example, ferromagnetic core 11 can provide a higher magnetic flux density in the coil 1 and an increase in the inductance of the coil 1.

[0069] FIG. 6 shows an alternative embodiment, in which the coil shown in FIG. 4 is connected to an EP core 11, the EP core 11 also integrally forming a housing. The EP core 11 consists of two halves which can subsequently be glued together. The EP core 11 allows the coil 1 to be electromagnetically shielded, in particular in the case of high-frequency applications, and thus increases the electromagnetic compatibility of the component.

[0070] In FIG. 7, there are four coil strings embedded in plastic 9, with the central axes 3 of the coils 1 being arranged parallel to each other. Such an arrangement is also called a package. Here, the four coil strings each have four inductive portions 7 and five contact portions 8. The package shown in FIG. 7 is only an example, and more coil strings, and in particular more than 20 coil strings, having any other number of inductive portions 7 and contact portions 8 may be used. In this exemplary embodiment, the contact portions 8 have been opened by recesses and then planarized. The dashed lines indicate three possible separation lines 12 for singulation, which run transversely with respect to the central axis 3 of the coils 1 and through the contact portions 8. Also conceivable are alternative embodiments in which singulation is effected along any other number of separation lines 12. Singulation parallel to the central axis 3 of the coils 1 is also possible. If the coil 1 is singulated parallel to the central axis 3 of the tube 2, the inductive portions 7 are connected to each other in series. Embedding a plurality of coil strings at the same time, rather than individually, enables the production process to be accelerated.

[0071] Primarily, the coils 1 are protected by the plastic 9 against mechanical influences, but also against temperature influences and chemical influences. However, the plastic 9 may also be mixed with particles having magnetic properties, such as, for example, iron powder or magnetic nanoparticles. The addition of magnetic particles to the plastic enables the inductance of the coil to be increased, and also to be adjusted on the basis of the proportion of magnetic particles in the plastic.

[0072] FIG. 8 shows a module composed of four inductive portions 7, which have likewise been embedded in plastic 9 and which have been singulated from the package in a manner analogous to the dashed lines in FIG. 7. The module shown in the figure is only an example, and more coils 1, and in particular more than 20 coils 1, may be arranged in the module. The contact surfaces themselves can be contacted from below and, if necessary, from the side, and may be contacted, for example, via solder pads or printed conductors, by means of a soldering process or adhesive process. The use of a module can result in a reduction in cycle time in mounting the coils 1. By installing a module instead of individual coils 1, for example an automatic pick-and-place machine only needs to position the component once on a printed circuit board, instead of several times. Moreover, space is saved by multiple coils being arranged within a module, compared to a plurality of individual coils being arranged adjacently.

[0073] The advantage of the inductive portions 7 being arranged as in FIG. 8 is that the individual inductive portions 7 can be connected in a variable manner. The coils 1 in the module may be designed to be connected to each other in parallel, in series or not at all. In the embodiment shown in FIG. 8, each coil 1 can be contacted individually. If, on the other hand, the module is contacted to two printed conductors running perpendicular to the longitudinal axis 3, the inductive portions 7 are electrically connected in parallel to each other. If the printed conductor is meandered under the module, the inductive portions 7 are connected in series.

[0074] FIG. 9 shows a single coil 1 that has been embedded in plastic 9. In the example shown, the coil 1 has 10 turns and planar contact portions 8. In other embodiments, however, the coil may have many more turns, and in particular even more than 20 turns. It may have been produced either by singulating the coils 1 from FIG. 8 parallel to the longitudinal axis 3 of the tube 2, or by embedding a single coil 1, as from FIG. 3, in plastic 9. Singulation of the coil 1 from a package, with the first separation parallel and subsequently transverse to the longitudinal axis of the coil, or the other way round, is also possible.

[0075] A coil 1 as shown in FIG. 9 has the advantage that it can be contacted via the planar contact portion 8, which is realized integrally with the coil 1. The integral realization of the coil 1 from the tube 2 makes it possible to dispense with additional connection techniques. For this reason, the coil 1 has a lower overall resistance, which in turn results in a low power loss. In addition, the thermal load is also reduced, especially at possible contacting points, thereby reducing the fault susceptibility of the coil.

[0076] Although the invention has been illustrated and described in detail by means of the preferred embodiment examples, the present invention is not restricted by the disclosed examples and other variations may be derived by the skilled person without exceeding the scope of protection of the invention.