Coil and method of its manufacture

Abstract

A 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) forming the tube wall (6) into a helix in the inductive section (7), and wherein the tube (2) has two contact sections (8) comprising a connection area (10) and at least one terminal area (11), wherein the connection area (10) has the same contour as an adjacent section of the helix, and wherein the terminal area (11) forms an electrical connection of the coil (1), and wherein the connection area (10) electrically connects the terminal area (11) to the inductive section (7). Further aspects relate to a module comprising several coils (1), a method for manufacturing a coil (1), and a method for manufacturing a module.

Description

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

[0002] The document DE 10 2019 103895 A1 describes a coil and a method for its production.

[0003] The document US 5 428 337 A describes a conductive winding.

[0004] The document JP H11 97270 A describes a flat coil and a method for its production.

[0005] 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.

[0006] 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.

[0007] Especially with small coils, the design of the contact and lead wires has a significant impact on the coil's electrical properties. The large ratio of the lead wires to the coil's dimensions significantly impacts the coil's properties as an electronic component.

[0008] The object of the present invention is to provide a coil with improved properties. Furthermore, the object of the present invention is to provide a manufacturing method for a coil.

[0009] The present object is achieved by a coil according to claim 1. Further embodiments of the coil and a method for producing the coil can be found in the further claims.

[0010] 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 gap forms the tube wall in the inductive section into a coil, and wherein the tube has at least one contact section which has a connecting region and at least one terminal region, wherein the connecting region has the same contour as an adjacent section of the coil, and the terminal region forms an electrical terminal of the coil, wherein the connecting region electrically connects the terminal region to the inductive section.

[0011] 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 longitudinal axis, with the longitudinal axis extending from the center of a base at the first end to the center of a base at the second end. In one embodiment, the tube can have a circular, oval, or rectangular cross-section. However, other cross-sections are also possible.

[0012] A helix can be described as a helical structure. The helix can, in particular, form the windings of the coil.

[0013] 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.

[0014] 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 sections 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] The connection area has the same contour as the adjacent area of ​​the coil. Therefore, deformation of the connection area, which would be transferred to the directly connected coil, is avoided. Deformation refers in particular to bends and embossing. Such a force acting on the connection area directly affects the inductive section as a bending moment and leads to deformation of the coil. The pitch of the coil, which means the regularity of the turns and the gaps in the coil, can deteriorate even with a small force acting on the connection area. For example, a coil can have a smaller gap width on one side and a larger gap width on the opposite side.A stronger force in the connection area can also easily cause a short circuit in the coil, since turns of the coil, especially those close to the connection area, can be bent together and then touch each other.

[0019] The contour is understood to be an external shape that the area or section of the helix has, viewed in a direction parallel to the longitudinal axis of the pipe. For example, if the pipe is square and the connecting area is located on a straight side of the square, the connecting area is also straight. If the adjacent section of the helix has a corner, the contour of the corner must also be present in the connecting section. In the case of a round pipe, the connecting section accordingly has the contour of a circular segment. An adjacent section of the helix and the connecting area, which have the same contour, can in particular be arranged parallel to one another.

[0020] The transition from the connection area to the inductive section can be straight along the longitudinal axis of the tube. By eliminating a bend or angle between the connection area and the inductive section, weakening of the material at this point can be avoided, thus preventing breakage. Furthermore, a straight transition prevents a change in the path or bending of a flowing current, thus avoiding unplanned inductances in the coil.

[0021] Preferably, the inductive region should not exhibit any deformation. Since the connecting region has the same contour as the adjacent section of the coil, deformation of the connecting region and thus the application of force to the connecting region can be avoided. A force applied to the connecting region, which also leads to deformation of the connecting region, can easily lead to deformations within the coil. Even a small deformation of the inductive region can lead to changes in the pitch, which characterizes the coil-to-gap ratio and the regularity of the coil turns, and to variations in the electrical properties of the coil, which means that these no longer meet the planned requirements. More severe deformations can compress individual coil turns and thus even lead to a short circuit in the coil.A short circuit between two turns does not necessarily result in a non-functional coil, but the short-circuited turn would not contribute to the inductance of the coil without a current flowing through it.

[0022] Furthermore, the connection area can be formed by deforming the tube wall. This allows for an integral coil design from the connection area up to and including the inductive section, keeping the coil's series resistance low.

[0023] The terminal area and the connecting area can be located in a plane perpendicular to a longitudinal axis of the tube. Such arranged terminal areas do not increase the overall dimensions of the coil, as the terminal area does not connect to the connecting area in the direction of the longitudinal axis of the tube. The overall coil length can thus be kept short relative to the coil, and a favorable form factor for the coil can be achieved.

[0024] Furthermore, the connection area can have a flat surface that forms a solderable connection. Accordingly, the coil can be designed, in particular, to be soldered onto a conductor track, for example, a printed circuit board.

[0025] The inductive section can be spaced from a support surface by part of the connection area. This has the advantage of mechanically and thermally insulating the inductive section from a support surface on which the coil is mounted. This inhibits the transmission of coil vibrations or heat to a mounting surface, such as a circuit board. The coil's magnetic field is also less influenced by a spaced-apart mounting surface, meaning the coil has the expected electrical properties. In one embodiment in which the coil can be surrounded by or embedded in a magnetic material, spacing the coil from a support surface ensures that sufficient magnetic material can be arranged between the coil and the support surface.In this way, the coil can be evenly enveloped by the magnetic material, which creates a uniform magnetic field around the coil and additionally protects the coil from all sides.

[0026] Spacing the inductive section can be achieved, for example, using L-shaped connection areas. A vertical part of the L-shaped connection area acts as a spacer, and a horizontal part can serve as the flat surface for electrical contact. The vertical part of the connection area separates the inductive section of the coil from a mounting surface, such as a circuit board, to which the coil can be electrically connected via the horizontal part.

[0027] The coil can also have a magnetic core. The use of a ferromagnetic core, for example, can ensure a higher magnetic flux density in the coil and increased inductance of the coil. Suitable materials for the core can be the metals nickel-zinc, manganese-zinc, and cobalt, as well as other alloys. The core is not limited to cores arranged exclusively inside the coil, but also includes cores that form the core integrally as part of a modular coil housing. The design of a coil with a modular coil housing can improve the electromagnetic compatibility of the coil. By using an EP core as a housing, for example, the electromagnetic shielding provided by the housing can be improved, especially in high-frequency applications, and the electromagnetic compatibility can thus be increased.

[0028] 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.

[0029] 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, particularly 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.

[0030] 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.

[0031] A further aspect of the present application relates to a module having at least two coils. The coils can, in particular, be the coils described above. 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 one another.

[0032] 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 connected in parallel or in series to impart a desired inductance to the entire module.

[0033] In this way, it is possible to assemble a module from several coils in such a way that the entire module has a higher or lower inductance than the individual coils.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] The procedure includes the following steps: a. Providing a tube with a tube wall made of an electrically conductive material, and b. Creating a gap in an inductive section of the tube, wherein the gap in the inductive section shapes the tube wall into a coil, and forming at least two sections of the tube into contact sections, c. Deforming a first part of the contact sections into at least one connection region, wherein a second part of the contact sections retains the shape of the tube wall and forms a connection region, wherein the connection region electrically connects the connection region to the inductive section.

[0038] 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, especially in a laser process together with the creation of the gap.

[0039] 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.

[0040] The above-mentioned step b. may include 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.

[0041] Accordingly, the entire step b. can be produced in a single process step, for example by laser cutting.

[0042] Furthermore, in step c, the connection region can be formed by deforming the first part of the contact section in a direction perpendicular to the longitudinal axis of the tube. Since the connection region is not deformed in a direction of the longitudinal axis of the tube, deforming the connection region in the direction perpendicular to the longitudinal axis does not lengthen the coil. By using a connection region that extends predominantly in a direction perpendicular to the longitudinal axis of a tube, it is possible to avoid excessively increasing the length of the entire coil compared to the length of the inductive section or the coil.

[0043] Furthermore, in step c, a first part of the contact sections can be formed into a connection area using a stamping process. Forming, such as bending or stamping, using a stamping process is efficient, reliable, and reproducible.

[0044] A second part of the contact sections, which can become the connection area during the stamping process, can be supported by a counter-punch or a support surface during the stamping process so that no bending forces act on the second part during the stamping process. The counter-punch can be shaped to match the contour or outer shape of the pipe. Since no bending moment acts on the connection section, the connection area retains the contour of the pipe wall from which it is formed and is therefore identical to the contour of the adjacent inductive section. Any force acting on the inductive section, which would lead to undesirable deformation of the inductive section, is also avoided. Even slight deformation of the inductive section can result in a change in the electrical properties of the coil.A greater force acting on the connection area can even lead to a short circuit in the inductive region, as two adjacent coil windings touch as a result of the force. By eliminating a bending moment in the connection area, the electrical properties of a coil manufactured using the aforementioned process become more reproducible and predictable.

[0045] 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 shapes the tube wall into a coil in the respective inductive section, and a contact section is formed between each two inductive sections. In step c., a first part of the contact sections can be formed into at least one connection region, and a second part of the contact sections can retain the shape of the tube wall and form a connection region, wherein the connection region electrically connects the connection region to the inductive section.

[0046] Such a coil strand can optimize coil handling in production. Multiple coils can be processed simultaneously, which in turn can lead to a reduction in production cycle times. Furthermore, material can be saved by creating multiple inductive sections in one tube.

[0047] In addition, the connection area can be formed by deforming the pipe wall in a direction perpendicular to the longitudinal axis of the pipe. Deforming the pipe wall to form a connection area in a direction perpendicular to the longitudinal axis of the pipe allows the formation of a connection area without causing a change in the length of the coil strand, be it stretching or compression. Deformation in a direction parallel to the longitudinal axis would inevitably result in a change in the length of the coil strand. Therefore, a coil strand formed in this way retains its defined overall length despite the forming process for the connection area. Handling of the coil strands is improved because the same dimensions and thus the framework conditions can be assumed in different production steps in the process line.A consistent length of the coil strands throughout the entire production process is particularly advantageous in the manufacturing process, as no additional measurements or new input of the framework conditions are necessary in various production steps, such as the separation of the coil strand.

[0048] Additionally, in the next step (d), the coil strand can be separated perpendicular to the longitudinal axis of the tube between two inductive sections. This allows one coil strand to be subsequently split into multiple coils. The coils can be separated individually, creating only one inductive section with two adjacent contact sections. However, it is also possible to separate multiple inductive sections, each held together by a contact section, from the coil strand to form a suitable overall coil consisting of several individual coils.

[0049] 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.

[0050] 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.

[0051] After embedding several parallel coil strands in a package, the coils can be separated transversely and parallel to the longitudinal axis 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.

[0052] Another aspect relates to a method for manufacturing a module. The package, which has several parallel coil strands, can be separated transversely to the longitudinal axis of the strands. With this option, it is also advantageous to run the separation line through the contact sections of the coils. There is no separation into individual coils parallel to the axis.

[0053] The module comprises at least two coils in a common housing, with the tube having a contact section divided into a connection area and a terminal area. The method for manufacturing the module comprises the following steps: Producing at least two coil strands by creating a plurality of inductive sections along each of the tubes, in each of which a gap 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, and wherein a first part of the contact sections is formed into at least one connection region, and wherein a second part of the contact sections retains the shape of the tube wall and forms a connection region, wherein the connection region electrically connects the connection region to the inductive section, arranging the coil strands in parallel, embedding the coil strands in a plastic which forms the housing, and separating the coil strands connected by the plastic along dividing lines which run transversely to a longitudinal axis of the coil strands to form the module.

[0054] 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 2 shows 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 according to an embodiment of the invention. Figure 5 shows a spatial representation of several coil strands embedded in plastic to form a package. Figure 6 shows a spatial representation of a coil that has been embedded in plastic and is a ready-to-use individual component.

[0055] 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.

[0056] In Figure 1a and 1b a 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 longitudinal axis 3, wherein the longitudinal 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.

[0057] 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 1 that are 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 longitudinal axis 3. The tube 2 is made of a primarily electrically conductive material.

[0058] The tube 2 represents a starting material used in the manufacture of a coil 1. During the manufacturing process, the Figure 1a The tube 2 shown must first be structured into a coil strand. Figure 2shows 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.

[0059] 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 of the inductive sections 7. During the manufacturing process, the contact sections 8 are partially formed into a connection area 11, with another part of the contact section becoming a connection area 10. During the structuring of the tube 2, a recess is formed in the contact sections 8, whereby a part of the tube wall 6 is removed.

[0060] The coil strand optimizes the handling of coils 1 during production. This allows multiple coils 1 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.

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

[0062] The different inductive sections 7 of the coil strand can have different or identical inductances. This makes it possible to produce different coils 1 from one tube 2, each of which can be varied in inductance, and is therefore 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 longitudinal 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.

[0063] In Figure 3A spatial representation of an intermediate product in the production of a coil 1 from the coil strand is shown. The coil strand was separated along dividing lines 12, which run transversely to the longitudinal axis 3 of the coil strand.

[0064] The coil 1 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 3The intermediate product shown can be structured, with the tube 2 being cut to a suitable length. The contact section 8 and the inductive section 7 are directly connected to each other. The contact section 8 and the inductive section 7 are formed integrally and in one piece from the structured tube wall 6.

[0065] Figure 4shows the coil 1 after a first part of the contact sections has been bent into two connection regions 11 using a stamping process, with an undeformed second part of the contact sections forming the connecting region 10. For this purpose, the second part of the contact sections was supported by a counter-stamp or a support surface during the stamping process in order to prevent any bending forces or moments from acting on the second part during the stamping process. The counter-stamp is preferably shaped to match the contour or outer shape of the tube 2. Due to the lack of bending moment on the connecting region 10, the connecting region 10 remains unchanged and has the same contour of the tube wall 6 as the contour of the adjacent inductive section.

[0066] Since the counter-punch neutralizes the force exerted by the punching process in the connection area 10 during the forming of the first part of the contact sections to the connection area 11, no bending moment acts on the adjacent coil. Thus, the coil retains its shape and pitch, and possible short circuits between adjacent turns can be eliminated.

[0067] In the embodiment shown in Figure 4 As shown, the connecting region 10 has the shape of a circular segment, since the tube 2 from which the coil 1 is made is circular. In an embodiment in which the tube 2 has a square basic shape, the connecting region 10 could, for example, have a straight contour. However, the shape of the connecting region 10 is not limited by this. Rather, the connecting region 10 can have any shape and contour that is similar to that of the tube 2 in an adjacent section.

[0068] The connection area 11 in Figure 4 was formed by a deformation of the pipe wall 6 in a direction perpendicular to the longitudinal axis 3 of the pipe 2. The deformation to a connecting region 11 in a direction perpendicular to the longitudinal axis 3 of the pipe 2 allows the connecting region 11 to be formed without causing a change in the length of the coil strand, be it an expansion or compression. A deformation in a direction parallel to the longitudinal axis 3 would inevitably result in a change in the length of the coil strand. If the connecting region 11 were to be deformed, for example, in the direction of the longitudinal axis 3 of the pipe 2 (in Figure 4(i.e. from the illustration), a coil strand having several such sections would be shortened due to the deformation. If, on the other hand, the connection area 11 is bent perpendicular to the longitudinal axis 3 of the tube 2, a coil strand formed in this way retains its defined overall length despite the forming process for the connection area 11. In this respect, the handling of the coil strands is improved, especially in the manufacturing process, because the same dimensions and the associated framework conditions, such as the position of the inductive sections, can be assumed in different manufacturing steps in the process line. When separating the coil strand, for example, a central cut between two inductive sections can be made automatically and without further measurements.

[0069] A further advantage of arranging the connection areas 11 perpendicular to the longitudinal axis 3 of the tube 2 is that the total coil length can be kept short, especially in comparison to the length of the helix, in order to achieve a better form factor for the coil 1.

[0070] Furthermore, the inductive section, which is in Fig. 4In the exemplary embodiment shown, the inductive section 7 is L-shaped and is spaced from the support surface by a portion of the connection region 11. In this way, the inductive section is mechanically and thermally insulated from a support surface. This inhibits the transmission of vibrations from the coil 1 or heat to a support surface, which may be a circuit board, for example. In addition, the distance between the inductive section 7 and a support surface ensures that sufficient space is created to completely embed the inductive section in a plastic 9. The magnetic field of the coil 1, and thus the inductance, is also less influenced by a spaced support surface.

[0071] A horizontal part of the Fig. 4The L-shaped connection area 11 shown forms a flat surface that provides a solderable connection. Accordingly, it is possible to solder the coil 1 onto a conductor track, for example, a printed circuit board. 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.

[0072] In Figure 5Four coil strands are embedded in plastic 9, with the longitudinal axes 3 of the coils 1 being arranged parallel to one another. Such an arrangement is also called a package. The four coil strands each have four inductive sections 7 and four contact sections 8. The package shown in Figure 7 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 by recesses and then stamped to form a non-deformed connecting region 10 and two connection regions 11. The dashed lines show several possible separating lines 12 for separation, which run transversely or parallel to the longitudinal axis 3 of the coils 1 and through the contact sections 8.Alternative embodiments are also conceivable, in which separation occurs along any number of dividing lines 12. If the coil 1 is separated parallel to the longitudinal axis 3 of the tube 2, the inductive sections 7 are connected in series. By embedding several coil strands simultaneously, rather than individually, the manufacturing process can be accelerated.

[0073] The plastic 9 acts as a type of housing, providing protection against potential hazards from the immediate environment. The protective function of the plastic can be pragmatically enhanced by adding particles with desired magnetic properties. The inductance can also be adjusted by adjusting the quantity or concentration of the magnetic particles in the plastic. In an alternative embodiment, a coil 1 could be connected to an EP core, with the EP core also integrally forming a housing. The EP core could consist of two halves that can then be glued together. An EP core can provide electromagnetic shielding for the coil 1, particularly in high-frequency applications, thus increasing the electromagnetic compatibility of the component.

[0074] It is also easy to create a module from a package that has several coils 1 in one housing. A package is used as shown in Fig. 5 shown, separated as required parallel and / or perpendicular to the longitudinal axis 3 of the tube 2. The Fig. 5 The package shown is merely an example, and much longer coil strands, with more coils 1, and a larger number of coil strands, can be arranged in the package. The contact surfaces of a module itself 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 times 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 1 within a module saves space compared to the arrangement of several individual coils 1 next to each other.

[0075] The coils 1 in the module can be designed to be connected to one another in parallel, in series, or not at all. In an embodiment in which several coils 1 are arranged side by side, each coil 1 can be contacted individually. However, if such a module is contacted with two conductor tracks running perpendicular to the longitudinal axis 3, the inductive sections 7 can be electrically connected in parallel. If the conductor track is arranged in a meandering pattern beneath the module, the inductive sections 7 can be connected in series. Thus, the coils 1 themselves can be connected to one another in a variety of ways within a module, but also within an electronic device.

[0076] Figure 6shows a single coil 1 which has been embedded in plastic 9. The contact section is arranged on the front side of the embedded coil 1 and has a circular segment-shaped connection area 10 and two L-shaped connection areas 11. The coil 1 can be produced either by separating the coils 1 from a package or by embedding a single coil 1, as shown in Figure 4 , made of plastic 9. List of reference symbols

[0077] 1Coil 2Tube 3Longitudinal axis 4Gap 5Sheath surface 6Tube wall 7Inductive section 8Contact section 9Plastic 10Connection area 11Connection area 12Parting lines

Claims

1. A method for producing modules, each having at least two coils (1) in a common housing, comprising the steps of: - producing at least two coil strands by producing a plurality of inductive sections (7) along each of two tubes (2), in each of which a gap (4) is produced, which forms a tube wall (6) into a coil in the respective inductive section (7), and wherein a contact section (8) is formed between each two inductive sections (7), and wherein a first part of the contact sections (8) is formed into at least one connection region (11), and wherein a second part of the contact sections (8) retains a contour of the tube wall (6) and forms a connection region (10), wherein the connection region (10) electrically connects the connection region (11) to the inductive section (7), - arranging the coil strands in parallel, - embedding the coil strands in a plastic (9),which forms the housing, - separating the coil strands connected by the plastic (9) along dividing lines (12) which run perpendicular to a longitudinal axis (3) of the coil strands and between inductive sections (7) to form the module., 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 a recess is formed in the contact sections (8) of the tube (2) by removing a region of the tube wall (6).

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

5. Method according to claim 1 to 4, wherein the connection regions (11) are each formed by a deformation of the first part of the contact section (8) in a direction perpendicular to the longitudinal axis (3) of the tube (2).

6. Method according to one of claims 1 to 5, wherein the first part of the contact sections (8) is formed into the connection region (11) by a stamping process with a counter-stamp.

7. The method according to claim 6, wherein the second part of the contact sections (8), which becomes the connecting region (10) by the stamping process, is supported by the counter-stamp during the stamping process, so that no bending forces act on the second part during the stamping process.

8. Method according to one of claims 1 to 7, additionally comprising the following step: separating the coil strands parallel to a longitudinal axis (3) of the coil strands.

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