INDUCTIVE COMPONENT AND METHOD FOR ADJUSTING AN INDUCTANCE VALUE

Abstract

An inductive component is provided, including: a wire winding, around which a magnetic foil is wrapped; an electrical shielding, which surrounds the magnetic foil, the magnetic foil including at least one magnetic layer, the at least one magnetic layer including a magnetic material, and the magnetic material being a nanocrystalline iron alloy; and a non-magnetic and non-conductive insulating layer, which includes a plastic and which is disposed between the magnetic foil and the wire winding. A method for adjusting an inductance value of an inductive component is also provided.

Claims

1.-15. (canceled)

16. An inductive component, comprising: a wire winding, around which a magnetic foil is wrapped; an electrical shielding, which surrounds the magnetic foil, wherein the magnetic foil comprises at least one magnetic layer, wherein the at least one magnetic layer comprises a magnetic material, and wherein the magnetic material is a nanocrystalline iron alloy; and a non-magnetic and non-conductive insulating layer, which comprises a plastic and which is disposed between the magnetic foil and the wire winding.

17. The inductive component according to claim 16, wherein the magnetic foil is self-adhesive.

18. The inductive component according to claim 16, wherein the magnetic foil is wrapped around the wire winding in a plurality of layers.

19. The inductive component according to claim 16, further comprising a magnetic core disposed within the wire winding.

20. The inductive component according to claim 16, wherein there is no magnetic core within the wire winding.

21. The inductive component according to claim 16, wherein the magnetic foil further comprises a non-magnetic carrier layer in addition to the at least one magnetic layer.

22. The inductive component according to claim 16, wherein the magnetic material is configured in a form of particles, which are embedded in a non-magnetic material.

23. The inductive component according to claim 16, wherein the at least one magnetic layer is made entirely of the magnetic material.

24. The inductive component according to claim 16, wherein the magnetic foil has a maximum thickness of 100 μm.

25. A method for adjusting an inductance value of an inductive component, the method comprising: providing a wire winding; applying a non-magnetic and non-conductive insulating layer comprising a plastic over the wire winding; wrapping the wire winding and the insulating layer with a magnetic foil, wherein the magnetic foil comprises at least one magnetic layer, wherein the at least one magnetic layer comprises a magnetic material, and wherein the magnetic material is a nanocrystalline iron alloy; and applying, after wrapping the magnetic foil, an electrical shielding over the wrapped magnetic foil.

26. The method according to claim 25, wherein a number of layers of the wrapped magnetic foil or a thickness of a magnetic layer of the wrapped magnetic foil is selected as a function of a target value of an inductance.

27. The method according to claim 25, wherein the inductance of the inductive component is measured before and/or after the step of wrapping with the magnetic foil, and wherein a number of layers of the wrapped magnetic foil is changed as a function of a deviation of a measured value from a target value.

28. The method according to claim 27, wherein, during the measurement, the magnetic foil is wrapped around the wire winding with a portion of a length of the magnetic foil and extends from the wrapped form with a further portion of the length of the magnetic foil, and wherein, after the measurement, the magnetic foil is wrapped further onto the wire winding.

29. The method according to claim 25, wherein an extending portion of the magnetic foil is cut off after the magnetic foil has been wrapped.

Description

[0039] The figures show:

[0040] FIG. 1 an embodiment of an inductive component in a lateral view,

[0041] FIG. 2 shows a base body of the component of FIG. 1,

[0042] FIG. 3 shows a foil for wrapping the base body of FIG. 2,

[0043] FIGS. 4A to 4D a method for adjusting an inductance in a schematic illustration.

[0044] In the following figures, the same reference signs preferably refer to functionally or structurally equivalent parts of the various embodiments.

[0045] FIG. 1 shows an inductive component 1 comprising a magnetic foil 2 for adjusting the inductance of the component 1. For illustrative purposes, FIG. 2 shows a base body 6 of the component 1 of FIG. 1, i.e., still without the wrapping with the foil 2.

[0046] The component 1 comprises a winding 3 (see FIG. 2) of a wire 4. The winding 3 is wrapped around a carrier body 5.

[0047] The carrier body 5 can, for example, be configured as a magnetic core. The carrier body 5 can be configured as a ferrite core, for example. The carrier body 5 can also be non-magnetic. In this case, a magnetic core can be disposed within the carrier body 5.

[0048] The base body 6 can alternatively be configured as an air-core coil. In this case, the carrier body 5 is non-magnetic and there is also no magnetic core in the carrier body 5.

[0049] The carrier body 5 can also be referred to as a coil former, the inductive component 1 as a coil.

[0050] The carrier body 5 comprises plastic, for example. The carrier body 5 is produced in an injection molding process, for example.

[0051] The wire 3 is configured as a copper wire, for instance. It can also be an aluminum, silver or gold wire. The wire can be insulated, for example with a lacquer. To improve the solderability and/or tendency to oxidize, the wire, in particular in the case of aluminum or copper, can be coated with other metals such as tin, silver, nickel or gold.

[0052] In the present case, the carrier body 5 has a circular cylindrical shape. The carrier body 5 can also have a different shape, for instance a cuboid shape. The carrier body 5 can also be a part of a larger body, for example an annular body.

[0053] In the present case, the carrier body 5 is shown as a hollow body, but can also be configured as a solid body. If it is configured as a hollow body, a magnetic core can also be inserted into the carrier body 5.

[0054] To adjust the inductance of the component 1, the wire winding 3 is surrounded by a magnetic foil 2. The foil 2 is wrapped to form a foil wrap 13. The foil 2 comprises a magnetic material. The foil 2 is in particular not or only slightly electrically conductive. An insulating layer can optionally be disposed between the foil 2 and the wire winding 3. The insulating layer can comprise a plastic, for example.

[0055] The foil 2 allows a precise adjustment of the inductance of the component 1 after the wire winding 3 has been produced. The foil 2 can be wrapped around the wire winding 3 in a suitable number of turns depending on the desired target value of the inductance. In the present case, the foil wrap 13 comprises four complete turns, so that four layers 18, 19, 20, 21 lie one over the other. The foil 2 can also comprise a different number of layers, for instance between 1 and 10 layers. It is also possible for the foil to comprise more than 10 layers. The foil 2 is in particular present in its basic form even prior to wrapping the component 1. The foil 2 is provided in the form of a roll, for example, unwrapped and wrapped around the base body 6. The foil 2 can, for example, also be provided in the form of a strip.

[0056] The foil wrap 13 forms a magnetic body outside the winding. The number of turns determines the magnetic thickness of the foil wrap 13. Due to its magnetic shielding effect, the foil wrap 13 can also be referred to as a shield winding.

[0057] The foil wrap 13 in particular has the shape of a tube arranged around the base body 6. The foil wrap 13 completely covers the wire winding 3 toward the outside, in particular in a direction radially outward from a winding axis. The wire ends 14, 15 of the wire 4 project from the wrapped foil 2.

[0058] For instance, the foil wrap 13 does not completely cover the length of the carrier body 5.

[0059] The outside of the foil wrap 13 can be surrounded by electrical shielding 16. The shielding 16 is in the form of a further foil or a coating, for example. The shielding 16 comprises a conductive material, for example a metal. An additional non-conductive foil can optionally be disposed over the shielding 16 for fixation.

[0060] FIG. 3 shows an example of a magnetic foil 2 for adjusting the inductance. The basic form of the foil 2 is present before and after wrapping the base body 6. The foil 2 is provided prior to wrapping as a roll, for example, or as a strip.

[0061] In the present case, the foil 2 comprises two carrier layers 7, 8 and an interposed magnetic layer 9. The foil 2 is consequently multilayered.

[0062] Instead of two carrier layers 7, 8, there can also be only one carrier layer or no carrier layer at all. The use of only one carrier layer or no carrier layer has the advantage that the total thickness of the foil 2 is smaller.

[0063] The carrier layers 7, 8 are non-magnetic, for instance, and serve to stabilize the magnetic layer 9. The carrier layers 7, 8 can in particular comprise plastic or be made of plastic. The carrier layers 7, 8 can also comprise an adhesive, in particular a cured adhesive.

[0064] The magnetic layer 9 comprises a non-magnetic material 12 filled with magnetic particles 11, for example. The non-magnetic material 12 can be a plastic, for example. The magnetic material 12 can also be an adhesive. The thickness d of the magnetic layer 9 is also referred to as the magnetic thickness of foil 2. The total thickness D of the foil consists of the thickness of the carrier layers 7, 8 and the thickness d of the magnetic layer 9. The maximum thickness of the foil 2 is 100 μm, for example.

[0065] Ferrite, for instance, is a suitable material for the magnetic particles 11. Depending on the desired properties, it is also possible to use pure iron or an amorphous or nanocrystalline iron alloy. The material can be in powder form. It can in particular also be a highly permeable material, for instance having a permeability of μ>1000.

[0066] The magnetic layer 9 can alternatively also be made entirely or primarily of the magnetic material. The magnetic layer 9 can in particular comprise only the magnetic material and no non-magnetic carrier material. The magnetic material is in particular not in the form of individual particles, but rather as a continuous layer. The magnetic layer 9 is in the form of an iron strip, for example. The strip can be made of ferrite, pure iron or an iron alloy, for example.

[0067] The carrier layers 7, 8 are particularly advantageous when using brittle magnetic layers 9, for instance an iron strip. Some highly permeable materials in particular exhibit a high degree of brittleness. The carrier layers 7, 8 make it possible to maintain the shape and the magnetic properties if cracks occur in the magnetic layer 9. For less brittle magnetic layers 9, a foil 2 without a carrier layer can also be used. It is also possible for an adhesive, which can also be used to attach the foil 2 to the component 1, to ensure the stability of the foil 2 in the event of cracks. In this case, too, the foil 2 can be configured without an additional carrier layer 7, 8, even when using a brittle magnetic layer 9.

[0068] The magnetic layer 9 can also be made of a plurality of sublayers. Each of the sublayers can have the structure of the magnetic layer 9 described above. The sublayers are glued together, for example. In this way, the thickness d of the magnetic layer 9 in the foil 2 can be adjusted.

[0069] The selection of the thickness d of the magnetic layer 9 can thus be used to determine how strongly one turn of the foil 2 around the base body 6 affects the inductance of the component 1.

[0070] For example, for a thick version with many sublayers of the magnetic layer 9, for instance 20 sublayers, the same magnetic thickness can be achieved by applying one single turn as can be achieved in a version with a single-layer magnetic layer 9 when applying many turns, for instance 20 turns. The total thickness of the foil wrap 13 can then vary greatly depending on the number of carrier layers 7, 8.

[0071] The magnetic layer 9 is, for example, connected to the carrier layers 7, 8 by means of a bonding agent, for instance an adhesive. The magnetic layer 9 can also be connected to the carrier layers 7, 8 via a purely thermal process.

[0072] The foil 2 has a bonding agent 10 on one surface, for example, in particular an adhesive. The bonding agent 10 can also be applied to both surfaces. The foil 2 can thus be attached to the base body 6 in a self-adhesive manner. The bonding agent 10 can alternatively also be applied later to the base body 6 and/or the foil 2. The layers 18, 19, 20, 21 can also be attached to one another by means of the bonding agent 10. The foil 2 can be flexible, for example, like an adhesive tape.

[0073] FIGS. 4A to 4D show method steps for adjusting an inductance of an inductive component, for example the inductive component 1 according to FIG. 1.

[0074] According to FIG. 4A, a base body 6 is provided, which comprises a winding 3 of a wire 4. The base body 6 can be configured according to FIG. 2. Through measurement, the inductance L of the base body 6 can be determined.

[0075] According to FIG. 4B, a foil 2 is provided. The foil 2 has the structure according to FIG. 3, for example. The foil 2 can also comprise a magnetic layer which is formed over its entire volume by a magnetic Material. The foil 2 can be constructed with or without carrier layers.

[0076] The foil 2 is provided in the form of a roll 17, for instance. The foil 2 can be self-adhesive. If the foil 2 is self-adhesive, the adhesive surface can be covered by a protective foil that is later removed before applying the foil. If the foil 2 is not self-adhesive, a bonding agent, in particular an adhesive, can be applied.

[0077] According to FIG. 4C, the foil 2 is wrapped around the base body 6. The number of turns of the obtained foil wrap 13 is determined, for example, as a function of the deviation of the measured inductance from a target value of the inductance. In the present case, two turns, corresponding to the two layers 18, 19, are applied in a first step. Optionally, an insulating layer can be applied over the wire winding 3 before the foil 2 is applied.

[0078] The foil 2 can be cut to the desired length before or after wrapping. A portion of the foil 2, in particular the roll 17, can project from the foil wrap 13 as shown, and not be cut off until the target value of the inductance has been reached.

[0079] The inductance L of the component 1 can be determined after or even during the wrapping process. If the inductance value corresponds to the target value and a portion of the foil 2 still projects, this portion of the foil 2 is cut off. The number of turns can now be set for a group of identical components, so that there is no need for measurement during production of these components.

[0080] If the measured value is below a target value, more of the foil 2 is wrapped around the base body 6 or a different foil 2 is wrapped around the base body 6.

[0081] Overall, the magnetic thickness and thus the inductance can be adjusted very precisely by adding further turns to the foil wrap 13. For example, depending on the required thickness of the foil wrap 13, the thickness can be varied in small increments, for example in 2.5% increments.

[0082] It is also possible to apply partial turns. For example, the foil can be wrapped around the base body 6 in 1.5 turns.

[0083] If the measured value is above the target value, the number of turns can be reduced or a foil 2 having a smaller thickness of the magnetic layer 9 can be used.

[0084] In the present case, the measured inductance is not yet sufficiently close to the target value, so the foil 2 is wrapped further around the base body 6.

[0085] According to FIG. 4D, two further turns, corresponding to two further layers 20, 21 of the foil 2, are now wrapped around the base body 6. The inductance can then be measured again. Since a target value has now been reached, the remainder of foil 2 is cut off. If the desired inductance has not yet been reached, the wrapping process can be continued.

[0086] Lastly, according to FIG. 4E, an electrical shielding 16 can optionally be applied over the foil wrap 13.

[0087] The foil wrap 13 is wrapped with one or more layers of another metal foil, for example, or coated with a metallic material. For example, a metallic foil, such as copper foil, aluminum foil or tinned copper foil, is applied over the magnetic foil.

[0088] An additional foil for improved fixation is disposed on the outside, for example (not depicted).

LIST OF REFERENCE SIGNS

[0089] 1 Component [0090] 2 Foil [0091] 3 Winding [0092] 4 Wire [0093] 5 Carrier body [0094] 6 Base body [0095] 7 Carrier layer [0096] 8 Carrier layer [0097] 9 Magnetic layer [0098] 10 Bonding agent [0099] 11 Magnetic particle [0100] 12 Non-magnetic material [0101] 13 Foil wrap [0102] 14 Wire end [0103] 15 Wire end [0104] 16 Electrical shielding [0105] 17 Roll [0106] 18 Layer [0107] 19 Layer [0108] 20 Layer [0109] 21 Layer [0110] d Thickness of the magnetic layer [0111] D Thickness of the foil