Method for producing a coil, method for producing modules, and module having two coils

Abstract

A method for manufacturing a coil (1) comprising the steps of: a. providing a tube (2) with a tube wall (6) made of an electrically conductive material, b. creating a gap (4) in an inductive section (7) of the tube (2), wherein the gap (4) in the inductive section (7) forms the tube wall (6) into a helix, and forming at least two sections of the tube into contact sections (8), wherein in step b. a coil strand is first produced by creating several inductive sections (7) along the tube (2), in each of which a gap (4) is created which forms the tube wall (6) into a helix in the respective inductive section, and wherein a contact section (8) is formed between each of two inductive sections (7), which, after separation of the coil strand, forms an electrical connection to the two adjacent inductive sections (7).

Description

[0001] The invention relates to a coil comprising a tube made of conductive material and a method for producing the coil.

[0002] In the course of the miniaturization of electrical circuits, it is of great interest to provide small inductive components that have low power dissipation, high current carrying capacity and reliable longevity.

[0003] Particularly in wire coils, a weak point can be the connection between the wire and a contact element required for external contact. The connection, which is usually made with welds or solder joints, can have at least a slightly increased resistance due to the use of alloys containing copper, tin, or nickel, or due to oxygen contamination. If the contact is poorly made, the resistance can also be significantly increased. This can result in high contact resistance, which causes high power loss. This can also lead to increased thermal stress at this point, which can lead to coil failure in a harmless case or, in a serious case, to a fire.

[0004] The object of the present invention is to provide a manufacturing method for a coil. Furthermore, the object of the present invention is to provide a module and a method for manufacturing a module.

[0005] The present object is achieved by a method according to claim 1. Further embodiments of the method, a method for producing a module and a module comprising two coils are the subject of the further claims.

[0006] A coil is proposed which comprises a tube with a tube wall made of an electrically conductive material, wherein the tube has an inductive section in which a gap is arranged in the tube wall, which forms the tube wall in the inductive section into a coil, and wherein the tube has two contact sections, in each of which the tube wall is formed into an electrical connection.

[0007] A tube can be defined as an elongated hollow body having an opening extending from a first end of the body through the entire body to a second end opposite the first end. The tube can be symmetrical about its central axis, with the central axis extending from the center of a base area at the first end to the center of a base area at the second end. In one embodiment, the tube can have a circular, oval, or rectangular cross-section. Other cross-sections are also possible.

[0008] A helix can be described as a helical structure. The helix can, in particular, form the windings of the coil.

[0009] The tube can, in particular, have a helical gap in the tube wall, through which the turns of the coil are formed from the tube. The tube is made of a conductive material. A conductive material is considered to be a material with a conductivity of over 10 4 < S / m, but in particular materials with a conductivity of over 10 5 < S / m or over 10 6 < S / m. Materials with very high conductivity, for example metals such as copper, aluminum, silver, or gold, can be suitable for this purpose. Industrial steels such as carbon steel, stainless steel, alloy steel, or tool steel can also be suitable as starting materials for the tube.

[0010] The tube has the inductive section and at least one contact section. The inductive section can form an inductance through the coil formed by the gap. The inductive section and the contact section are formed integrally from a material of the tube wall. Therefore, no connecting components, such as solder, are required to connect the inductive section to the contact section. Instead, the inductive section and the contact section can be formed by appropriately structuring the tube wall and remain connected to each other by the tube material.

[0011] The coil has the advantage that no internal connection points are required to connect an inductor to a terminal. Instead, the inductive region and the contact region can be formed integrally. The coil has a lower overall resistance than a coil that requires internal connection points to connect an inductor to a terminal. Furthermore, the elimination of internal contacts also eliminates the thermal and mechanical stress that would otherwise occur at the possible internal contacts, thus reducing the coil's susceptibility to failure.

[0012] The tube does not have to be round in cross-section, but can be oval, square, rectangular, polygonal, square with rounded corners, rectangular with rounded corners, or polygonal with rounded corners. A square cross-section offers the advantage of optimal utilization of the available installation space for a given height or width.

[0013] Depending on the coil's intended application, the base area of ​​the tube can be flat, meaning the tube's dimensions spanning the base area are large compared to its height, and the height can be small. Alternatively, the tube can have a small base area yet a considerable height. For example, if the coil is installed on a circuit board mounted in a narrow housing, a flat, flat shape can be advantageous. However, if limited space is available on the circuit board itself, a tubular shape with a small base area but a considerable height may be advantageous.

[0014] Furthermore, the coil can have a magnetic core. The use of a ferromagnetic core, for example, can provide a higher magnetic flux density in the coil and increased inductance. Suitable materials for the core can be the metals nickel-zinc, manganese-zinc, and cobalt, as well as other alloys. In this case, the core is not limited to cores located exclusively inside the coil, but also includes cores that form the core integrally as part of a modular coil housing.

[0015] Designing a coil with a modular coil housing can improve the coil's electromagnetic compatibility. For example, by using an EP core as a housing, the electromagnetic shielding provided by the housing can be improved, especially in high-frequency applications, and thus electromagnetic compatibility can be increased.

[0016] Furthermore, the tube can be embedded in a plastic to protect it primarily against mechanical influences, but also against temperature and chemical influences. Suitable plastics include epoxy resin, phenyl resin, and even silicone. Embedding the tube in a plastic makes the coil component more suitable for assembly using an automated assembly machine, for example, using a pick-and-place process.

[0017] Powder with magnetic properties, such as iron powder, or magnetic nanoparticles can be mixed into the plastic. By adding magnetic particles to the plastic, the inductance of the coil can be increased and the electrical properties improved. The inductance can be adjusted by changing the proportion of magnetic particles in the plastic. Even when embedded in a plastic, regardless of whether the plastic contains a proportion of magnetic powder, the coil can have a magnetic core to increase the inductance of the coil. By embedding the coil in a plastic, especially in a plastic that contains a proportion of powder with magnetic properties, the electromagnetic shielding of the component can be improved, especially in high-frequency applications, and the electromagnetic compatibility can be increased.

[0018] Furthermore, the coil can have an outer diameter of 0.2 to 50 mm. Preferably, the outer diameter of the coil can be in the range between 0.5 to 20 mm. This size is particularly suitable for providing coils suitable for applications on a printed circuit board. The outer diameter should not be smaller than 0.2 mm, preferably not smaller than 0.5 mm, since otherwise a coil would be produced that is so small that automatic parts handling would be associated with considerable technical difficulties. The outer diameter should not be larger than 50 mm, preferably not larger than 20 mm, since otherwise manufacturing the coil from a tube would be uneconomical.

[0019] The contact section can have a flat surface that forms a solderable connection. Accordingly, the coil can be designed, in particular, to be soldered onto the conductor track, for example, of a printed circuit board.

[0020] A further aspect of the present application relates to a module having at least two coils. The coils may, in particular, be the coils described above.

[0021] The at least two coils are arranged in a common housing. The housing can be formed from a plastic material in which both coils are embedded. The two coils can be arranged spatially parallel to each other.

[0022] Preferably, the coils are arranged so that they can be electrically contacted individually and are not interconnected within the module. In an alternative embodiment, the coils can be electrically interconnected in parallel or series to impart a desired inductance to the entire module. In this way, it is possible to assemble a module from multiple coils such that the entire module has a higher or lower inductance than the individual coils.

[0023] The use of the module can shorten the assembly process for a printed circuit board with a large number of coils, thus leading to a reduction in cycle times in a manufacturing process. By mounting the module instead of a large number of individual coils, only one module needs to be positioned on the circuit board during assembly, for example, using a pick-and-place machine. The module can thus simplify a subsequent process in which the module is installed.

[0024] Furthermore, arranging multiple coils within a module saves space compared to arranging several individual coils side by side. In applications where space is very limited, such as a printed circuit board for a mobile device such as a smartphone, this space saving can be a significant advantage. Furthermore, using the module instead of individually embedded coils can save housing material.

[0025] A further aspect of the present application relates to a method for producing a coil. The coil can, in particular, be the coil described above.

[0026] The procedure includes the following steps: a. Providing a tube having a tube wall made of an electrically conductive material, and b. Creating a gap in an inductive portion of the tube, wherein the gap in the inductive portion forms the tube wall into a coil, and forming at least two portions of the tube into contact portions.

[0027] The inductance of the inductive section can only be created by creating the gap. The gap can be a cutting gap created with a laser. The shape of the contact section can also be created with a laser, particularly in a laser process that also creates the gap.

[0028] A laser process is suitable for creating the gap in the inductive sections, as well as for creating a recess in the contact sections of the tube. The laser process has the advantage of being flexible and fast. Furthermore, the laser process has the advantage of not generating any mechanical stress, as it operates without contact and leaves little residue. Other alternatives for creating the gap include milling, sawing, or waterjet cutting.

[0029] The above-mentioned step b. may comprise a further sub-step, wherein a recess is formed in the contact section of the tube by removing a portion of the tube wall. The recess in the contact section of the tube and the gap in the inductive region can be created together in a single process step. Accordingly, the entire step b. can be created in a single process step, for example, by laser cutting.

[0030] In a further sub-step of step b, an area of ​​the tube wall that was not removed in the first sub-step can be planarized. This area can be formed into a flat electrical connection that can be soldered to a conductor track, for example, on a circuit board. Planarization can be achieved by applying pressure to the desired location, for example, with a stamp.

[0031] Additionally, in step b., a coil strand can first be created by creating several inductive sections along the tube, in each of which a gap is created that forms the tube wall into a coil in the respective inductive section, and a contact section is formed between each two inductive sections, which forms an electrical connection after the coil strand is separated. Using such a coil strand, the handling of the coils in production can be optimized. This allows several coils to be processed simultaneously, which in turn can lead to a reduction in cycle times in production. Furthermore, material can be saved by creating several inductive sections in one tube.

[0032] In an additional step, the coil features an EP core. This increases the coil's inductance and electromagnetic compatibility.

[0033] Multiple coils or coil strands can be embedded in plastic, thus forming a package. The coils or coil strands can already have a magnetic core at this point. It is advantageous to arrange the coil strands parallel to each other before embedding. Embedding multiple coil strands simultaneously, rather than individually, can accelerate the manufacturing process. The plastic protects the coils from mechanical, thermal, and chemical influences. Powder with magnetic properties or magnetic nanoparticles can also be mixed into the plastic. By adding magnetic particles to the plastic, the inductance of the coil can be increased and adjusted by adjusting the proportion of magnetic particles in the plastic.

[0034] It can be advantageous to arrange magnetic cores in the coil strands or coils. This can increase the inductance of the coils or coil strands. Furthermore, arranging the cores in the coil strands before embedding them in a plastic allows for the production of coils with a magnetic core embedded in a plastic that may also contain magnetic components. This can increase the inductance and electromagnetic compatibility of the coils.

[0035] After embedding several parallel coil strands in a package, the coils can be separated transversely and parallel to the centerline of the coil strands. It is advantageous to run the separation line through the contact sections of the coils. This separates the package into individual coils. It is possible to separate the package transversely and then parallel, or to separate the package first parallel and then transversely.

[0036] Another aspect relates to a method for manufacturing a module. The package, which has several parallel coil strands, can be separated transversely to the center axis of the strands. There is no separation into individual coils parallel to the axis.

[0037] The module has at least two coils in a common housing, each of the coils having a tube with a tube wall made of an electrically conductive material, the tube having an inductive section in which a gap is arranged in the tube wall, which forms the tube wall in the inductive section into a coil, and the tube having a contact section in which the tube wall is formed into an electrical connection.The method for producing the module comprises the following steps: - producing at least two coil strands, in that a plurality of inductive sections are produced along each of the tubes, in each of which a gap is produced which forms the tube wall into a coil in the respective inductive section, and wherein a contact section is formed between each two inductive sections, which contact section forms an electrical connection to the two adjacent inductive sections after the coil strand has been separated. Arranging the coil strands in parallel, embedding the coil strands in a plastic that forms the housing, and separating the coil strands connected by the plastic along dividing lines that run transversely to a center axis of the coil strands to form the module.

[0038] In addition, the following aspects are possible embodiments of the present invention: Aspect 1: Coil (1) comprising a tube (2) with a tube wall (6) made of an electrically conductive material, wherein the tube (2) has an inductive section (7) in which a gap (4) is arranged in the tube wall (6), which forms the tube wall (6) into a coil in the inductive section (7), and wherein the tube (2) has two contact sections (8), in each of which the tube wall (6) is shaped into an electrical connection. Aspect 2: Coil (1) according to aspect 1, wherein the coil (1) has a core (11). Aspect 3: Coil (1) according to aspect 1 or 2, wherein the tube (2) is embedded in a plastic (9). Aspect 4: Coil (1) according to aspect 3, wherein the plastic (9) is mixed with magnetic powder, magnetic particles, or another magnetic material. Aspect 5: Coil (1) according to one of the preceding aspects, wherein the coil (1) has an EP core (11).Aspect 6: Coil (1) according to one of the preceding aspects, wherein the tube (2) has an outer diameter between 0.2 mm and 50 mm. Aspect 7: Coil (1) according to one of the preceding aspects, wherein the contact sections (8) each have a flat surface, each forming a solderable connection. Aspect 8: Module comprising at least two coils (1) according to one of the preceding aspects, which are arranged in a common housing. Aspect 9: Method for producing a coil (1), comprising the steps: a. Providing a tube (2) with a tube wall (6) made of an electrically conductive material, b. Creating a gap (4) in an inductive section (7) of the tube (2), wherein the gap (4) in the inductive section (7) forms the tube wall (6) into a coil, and forming at least two sections of the tube into contact sections (8).Aspect 10: Method according to aspect 9, wherein a laser process is used to produce the gap (4) and to form the contact sections (8). Aspect 11: Method according to one of aspects 9 or 10, wherein in a sub-step of step b. a recess is formed in the contact section (8) of the tube by removing a region of the tube wall (6). Aspect 12: Method according to aspect 11, wherein the recess in the contact section (8) of the tube (2) and the gap (4) in the inductive section (7) are produced together in a single method step. Aspect 13: Method according to aspect 11 or 12, wherein in a further sub-step of step b. a region in the contact section (8) of the tube wall (6) that was not removed in the first sub-step is planarized. Aspect 14: Method according to one of aspects 9 to 13, wherein in step . b.First, a coil strand is produced by creating a plurality of inductive sections (7) along the tube (2), in each of which a gap (4) is created, which forms the tube wall (6) into a coil in the respective inductive section, and wherein a contact section (8) is formed between each two inductive sections (7), which contact section forms an electrical connection to the two adjacent inductive sections (7) after the coil strand has been separated. Aspect 15: Method according to aspect 14, wherein the coil (1) has an EP core (11). Aspect 16: Method according to aspect 14, additionally comprising the following step: producing a plurality of coil strands and embedding a plurality of coil strands in a plastic (9), wherein coil strands are arranged parallel to one another. Aspect 17: Method according to aspect 16, wherein cores (11) are arranged in the coil strands. Aspect 18: Method according to aspects 16 and 17, wherein the plastic (9) is coated with magnetic powder,magnetic particles or another magnetic material. Aspect 19: Method according to one of aspects 16 to 18, additionally comprising the following step: separating the coil strands transversely and / or parallel to a central axis (3) of the coil strands. Aspect 20: Method for producing modules, each comprising at least two coils (1) in a common housing, wherein each of the coils (1) comprises a tube (2) with a tube wall (6) made of an electrically conductive material, wherein the tube (2) comprises an inductive section (7) in which a gap (4) is arranged in the tube wall (6), which forms the tube wall (6) into a coil in the inductive section (7), and wherein the tube comprises a contact section (8) in which the tube wall (6) is formed into an electrical connection, comprising the steps of: producing at least two coil strands by producing a plurality of inductive sections (7) along each of the tubes (2),in each of which a gap (4) is created which forms the tube wall into a coil in the respective inductive section, and wherein a contact section is formed between each two inductive sections, which contact section forms an electrical connection to the two adjacent inductive sections (7) after separation of the coil strand, parallel arrangement of the coil strands, embedding the coil strands in a plastic which forms the housing, separating the coil strands connected by the plastic along dividing lines (12) which run transversely to a central axis of the coil strands to form the module.

[0039] In the following, the invention is described in more detail using schematic representations of exemplary embodiments. Figure 1a shows a spatial representation of a possible design of a pipe. Figure 1b shows a spatial representation of a possible second embodiment of a pipe. Figure 2shows a spatial representation of a coil strand. Figure 3 shows a spatial representation of an intermediate product in the production of a coil from the coil strand. Figure 4 shows a spatial representation of a coil whose contact sections are open and planarized. Figure 5 shows a spatial representation of a coil, as in Figure 4 , which, however, has a magnetic core - cylindrical core - and is embedded in plastic. Figure 6 shows a spatial representation of a coil arranged in a removable housing with an integrated core - EP core. Figure 7 shows a spatial representation of several coil strands embedded in plastic to form a package. Figure 8 shows a spatial representation of several coils that are embedded in plastic and have been separated transversely to the central axis of the coil strands. Figure 9shows a spatial representation of a coil that has been embedded in plastic and is a ready-to-use individual component.

[0040] Identical, similar, or apparently identical elements are designated by the same reference numerals in the figures. The figures and their proportions are not to scale.

[0041] In Figures 1a and 1ba tube 2 is shown, each with a round and a rounded square cross-sectional area. A tube 2 is an elongated hollow body having an opening extending from a first end of the body through the entire body to a second end opposite the first end. The tube 2 can be symmetrical about its central axis 3, wherein the central axis 3 extends from the center of the base at the first end to the center of the base of the second end. In one embodiment, the tube 2 can have a circular, oval, rectangular, or polygonal cross-sectional area. Other cross-sections are also possible.

[0042] The tube 2 can have an outer diameter of 0.2 to 50 mm. Preferably, the outer diameter of the tube 2 can be in the range between 0.5 and 20 mm. This size is particularly suitable for producing coils suitable for applications on a printed circuit board. The tube wall 6, whose thickness is determined by the distance between the inner radius and 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 jacket surface 5 of the tube 2 runs along the outer radius in the direction of the central axis 3. The tube 2 is made of a primarily electrically conductive material.

[0043] The tube 2 represents a raw material used in the manufacture of a coil. The process for manufacturing the coil is described in Figures 1 to 3 explained, showing the intermediate products in the production of the coil. Figure 4 and Figure 5 , 6 , 8 and 9show possible embodiments of coil 1.

[0044] During the manufacturing process, the Figure 1a The tube 2 shown must first be structured into a coil strand. Figure 2 shows the coil strand. The tube 2 can be structured, in particular, by a laser process, in which inductive sections 7 and contact sections 8 are formed in the tube 2. The inductive sections 7 and the contact sections 8 alternate along the tube 2.

[0045] A gap 4 is created in the inductive sections 7, which penetrates a tube wall 6 and forms the tube wall 6 into a coil. This creates an inductance in the inductive sections 7. The contact sections 8 form electrical connections after the coil strand is separated. A recess is formed in the contact sections 8 during the structuring of the tube 2, whereby a portion of the tube wall 6 is removed.

[0046] The coil strand optimizes coil handling during production. This allows multiple coils to be processed simultaneously, resulting in a reduction in production cycle times. Furthermore, material can be saved by creating multiple inductive sections 7 in one tube 2.

[0047] The inductive sections 7 are integrally connected to each other by the contact sections 8 and have no unnecessary contact resistances between each other.

[0048] The different inductive sections 7 of the coil strand can have different or identical inductances. This makes it possible to produce different coils from one tube 2, each of which can be varied in inductance, making them suitable for a wide variety of applications. The inductances can be varied, for example, by the number of turns formed by the gap 4, or by the distance of the gap 4 in the direction of the central axis 3 after one revolution around the tube 2, which corresponds to the width of the turns. In the embodiment of Figure 2 the columns 4 shown are the same and consequently the inductance of the individual inductive sections 7 is also the same.

[0049] In Figure 3A three-dimensional representation of an intermediate product in the production of a coil from the coil strand is shown. The coil strand was separated along dividing lines that run perpendicular to the central axis 3 of the coil strand.

[0050] The coil comprises a tube 2 made of electrically conductive material, wherein a gap 4, which runs along a jacket surface 5 and around the longitudinal axis 3 of the tube 2, has been created and thus forms an inductive section 7. In an alternative embodiment, the entire tube 2 can be structured in such a way that only a single inductive section 7 and two contact sections 8 adjacent to it are produced. Accordingly, the tube 2 can be Figure 3 shown intermediate product, whereby the tube 2 must be cut to a suitable length.

[0051] The contact section 8 and the inductive section 7 are connected to each other by a connecting section 10. The contact section 8, the connecting section 10, and the inductive section 7 are formed integrally and in one piece from the structured tube wall 6. The connecting section 10 is sufficiently wide so that it is insignificant for the resistance of the coil 1.

[0052] Figure 4 shows coil 1 after planarization of the contact sections. The contact sections 8 of tube 2, which lie between the inductive sections 7, have been planarized. By planarizing the contact sections 8, an electrical connection is created as a flat surface, which is suitable for enabling electrical contact. The Figure 4 The embodiment shown is suitable, for example, to be contacted on the conductor tracks of a printed circuit board by means of a soldering process.

[0053] However, the design of the contact sections 8 is not limited to the embodiments shown.

[0054] In particular, the shape of the contact sections 8 can be adapted to a housing shape.

[0055] Figure 5 shows the Figure 4 coil shown 1, which is additionally equipped with a magnetic core 11. In addition, the coil 1 is embedded in plastic 9, which may contain magnetic particles. The use of a ferromagnetic core 11, for example, can provide a higher magnetic flux density in the coil 1 and increase the inductance of the coil 1.

[0056] Figure 6 shows an alternative embodiment in which the Figure 4The coil shown is connected to an EP core 11, wherein the EP core 11 also integrally forms a housing. The EP core 11 consists of two halves, which can then be glued together. The EP core 11 allows the coil 1, especially in high-frequency applications, must be electromagnetically shielded and thus the electromagnetic compatibility of the component increased.

[0057] In Figure 7 Four coil strands are embedded in plastic 9, with the center axes 3 of the coils 1 arranged parallel to each other. Such an arrangement is also called a package. The four coil strands each have four inductive sections 7 and five contact sections 8. In the Figure 7The package shown is merely an example, and more coil strands, and in particular more than 20 coil strands, with any desired number of inductive sections 7 and contact sections 8 can be used. In this exemplary embodiment, the contact sections 8 have been opened up by recesses and then planarized. The dashed lines show three possible separating lines 12 for separation, which run transversely to the central axis 3 of the coils 1 and through the contact sections 8. Alternative embodiments are also conceivable, in which separation takes place along any desired number of separating lines 12. Separation parallel to the central axis 3 of the coils 1 is also possible. If the coil 1 is separated parallel to the central axis 3 of the tube 2, the inductive sections 7 are connected to one another in series.By embedding multiple coil strands 1 simultaneously, rather than individually, the manufacturing process can be accelerated.

[0058] The plastic 9 primarily protects the coils 1 against mechanical, thermal, and chemical influences. However, the plastic 9 can also be mixed with particles with magnetic properties, such as iron powder or magnetic nanoparticles. By adding magnetic particles to the plastic 9, the inductance of the coil 1 can be increased and adjusted by adjusting the proportion of the particles in the plastic.

[0059] Figure 8 shows a module consisting of four inductive sections 7, which are also embedded in plastic 9 and which are arranged analogously to the dashed lines in Figure 7have been separated from the package. The module shown in the figure is merely an example and more coils 1, and in particular more than 20 coils 1, can be arranged in the module. The contact surfaces themselves can be contacted from below and, if necessary, from the side and can be contacted, for example, via solder pads or conductor tracks using a soldering or adhesive process. The use of a module can lead to a reduction in cycle time when assembling the coils 1. By installing a module instead of individual coils 1, a pick-and-place machine, for example, only has to position the component on a circuit board once instead of several times. In addition, the arrangement of several coils within a module saves space compared to the arrangement of several individual coils next to one another.

[0060] The advantage of arranging the inductive sections 7 as shown in Figure 8is the variable connection option of the individual inductive sections 7 . The coils 1 in the module can be designed to be connected in parallel, in series or not at all. Figure 8 In the embodiment shown, each coil 1 can be contacted individually. However, if the module is contacted with two conductor tracks running perpendicular to the longitudinal axis 3, the inductive sections 7 are electrically connected in parallel. If the conductor track is laid in a meandering pattern beneath the module, the inductive sections 7 are connected in series.

[0061] In Figure 9 1 shows a single coil 1 which has been embedded in plastic 9. In the example shown, the coil 1 has 10 turns and planar contact sections 8. In other embodiments, however, the coil can have many more turns, and in particular more than 20 turns. It can be produced either by separating the coils 1 from Figure 8parallel to the longitudinal axis 3 of the tube 2, or by embedding a single coil 1, as shown in Figure 3 , made of plastic 9. Separation of the coil 1 from a package, with the first separation running parallel and subsequently transverse to the longitudinal axis of the coil, or vice versa, is also possible.

[0062] A coil 1 as in Figure 9 has the advantage that it can be contacted via the planar contact section 8, which is integrally formed with the coil 1. The integral formation of the coil 1 from the tube 2 eliminates the need for additional connection techniques. For this reason, the coil 1 has a lower overall resistance, which in turn leads to lower power loss. Furthermore, the thermal load is also reduced, especially at potential contacts, thereby reducing the susceptibility of the coil 1 to failure. List of reference symbols

[0063] 1Coil 2Tube 3Central axis 4Gap 5Shell surface 6Tube wall 7Inductive section 8Contact section 9Plastic 10Connection section 11Core / EP core 12Parting lines

Claims

1. A method for producing a coil (1), comprising the steps of: a. Providing a tube (2) with a tube wall (6) made of an electrically conductive material, b. Creating a gap (4) in an inductive section (7) of the tube (2), wherein the gap (4) in the inductive section (7) forms the tube wall (6) into a coil, and forming at least two sections of the tube into contact sections (8), wherein in step b. first, a coil strand is produced by producing a plurality of inductive sections (7) along the tube (2), in each of which a gap (4) is produced which forms the tube wall (6) into a coil in the respective inductive section, and wherein a contact section (8) is formed between each two inductive sections (7), which contact section forms an electrical connection to the two adjacent inductive sections (7) after the coil strand has been separated.

2. The method according to claim 1, wherein a laser process is used to create the gap (4) and to form the contact sections (8).

3. Method according to one of claims 1 or 2, wherein in a sub-step of step b. a recess is formed in the contact section (8) of the tube by removing a region of the tube wall (6).

4. The method according to claim 3, wherein the recess in the contact section (8) of the tube (2) and the gap (4) in the inductive section (7) are produced together in a single method step.

5. The method according to claim 3 or 4, wherein in a further sub-step of step b., an area in the contact section (8) of the pipe wall (6) which was not removed in the first sub-step is planarized.

6. Method according to one of claims 1 to 5, wherein the coil (1) has an EP core (11).

7. Method according to one of claims 1 to 6, additionally comprising the following step: - producing a plurality of coil strands and embedding a plurality of coil strands in a plastic (9), wherein coil strands are arranged parallel to one another.

8. The method according to claim 7, wherein cores (11) are arranged in the coil strands.

9. Method according to one of claims 7 and 8, wherein the plastic (9) is mixed with magnetic powder, magnetic particles or another magnetic material.

10. Method according to one of claims 7 to 9, additionally comprising the following step: - separating the coil strands transversely and / or parallel to a central axis (3) of the coil strands.

11. A method for producing modules, each comprising at least two coils (1) in a common housing, wherein each of the coils (1) comprises a tube (2) with a tube wall (6) made of an electrically conductive material, wherein the tube (2) comprises an inductive section (7) in which a gap (4) is arranged in the tube wall (6), which forms the tube wall (6) into a coil in the inductive section (7), and wherein the tube comprises a contact section (8) in which the tube wall (6) is formed into an electrical connection, comprising the steps of: - producing at least two coil strands by producing several inductive sections (7) along each of the tubes (2), in each of which a gap (4) is produced, which forms the tube wall into a coil in the respective inductive section, and wherein a contact section is formed between each two inductive sections,which, after separation of the coil strand, forms an electrical connection to the two adjacent inductive sections (7), - parallel arrangement of the coil strands, - embedding the coil strands in a plastic which forms the housing, - separating the coil strands connected by the plastic along dividing lines (12) which run transversely or parallel to a central axis of the coil strands to the module., 12. Module comprising at least two coils (1) which are arranged in a common housing, wherein each of the coils (1) has a tube (2) with a tube wall (6) made of an electrically conductive material, wherein the tube (2) has an inductive section (7) in which a gap (4) is arranged in the tube wall (6), which forms the tube wall (6) in the inductive section (7) into a coil, and wherein the tube has a contact section (8) in which the tube wall (6) is shaped into an electrical connection, wherein the housing is formed by a plastic in which both coils are embedded, wherein the coils are arranged parallel to one another or along a common central axis.

13. Module according to claim 12, wherein the inductive sections (7) are connected to each other in series.

14. Module according to claim 12, wherein each of the coils (1) can be contacted individually.

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