Coil former, inductor component and method for adjusting inductance

Abstract

The invention relates to a coil former (1) for an inductor component (7) comprising a base body (2) with some areas of the base body wrapped with an electrically insulating foil (3). An inductor component (7) comprises a coil former (1) and a winding (8) wound around the coil former (1), such that the foil (3) is arranged between the base body (2) and the winding (8). In a method for adjusting the inductance, the length of the foil (3) is selected according to a target value of the inductance.

Description

Technical Field

[0001] The present invention relates to a coil former for an inductor component and an inductor component comprising a coil former with a wire winding. This may be an air-core coil, i.e. a coil without a magnetic core. The inductor component is used in stereo systems, etc. Background Art

[0002] For many applications, it is desirable to precisely tune the inductance of a component, at least over a statistical average of a group of inductors (a batch). Resonant applications in particular require highly accurate tuning of the inductance.

[0003] Geometry strongly influences the inductance of electrical components, particularly in the case of air-core coils. Highly precise inductance values ​​can only be produced within certain physical limits and require precise control of the geometry. For inductors with or without ferrite cores, variations in material properties and operating temperature also lead to variations in inductance. Correcting deviations in the finished component's inductance from the desired target value is called "regulation" or "tuning."

[0004] Documents DE 36 18 122 A1, DE 39 26 231 A1, DE 199 52 192 A1 and DE 10 2008 063312 A1 describe adjustable inductance components. Adjustment is usually achieved by pushing a core of soft magnetic material into or out of the interior of the winding, or by stretching or compressing the winding. Summary of the Invention

[0005] The object of the present invention is to provide an improved coil former, an improved inductive component and a method for adjusting the inductance of an inductive component.

[0006] According to a first aspect of the present invention, a coil former is configured as a carrier for winding wire of an inductive component. The coil former includes a base body, at least some areas of which are wrapped with an electrically insulating foil. The diameter of the coil former is selectively increased by wrapping with the foil. Thus, after the wire has been wound onto the coil former and onto at least some areas of the foil, the inductance can be adjusted in a targeted manner.

[0007] In one embodiment, the base of the coil former is made of a non-magnetic material. This could be a plastic material, for example. Consequently, the inductor component can be constructed as an air-core coil, i.e., without a magnetic core around which the wire is wound. The coil former thus serves only as a carrier for the wire and does not guide the magnetic flux. In such an embodiment, the inductance is particularly strongly dependent on the coil geometry, particularly the diameter, making precise fine-tuning possible by varying the diameter.

[0008] For example, the thickness of the foil is significantly less than 1 mm. For example, the maximum thickness of the foil is 100 μm. In particular, the thickness of the foil can be between 10 and 40 μm.

[0009] In an alternative embodiment, the base may be made of a magnetic material. For example, this may be a ferrite core.

[0010] For example, the foil is wrapped helically around the substrate. The length of the foil and, if the geometry of the wrapping is fixed, the number of turns of the foil around the substrate can also be defined according to the target value of the inductance. For example, the number of turns can vary between one and four turns.

[0011] The foil is typically arranged in such a way that a winding of a wire can be arranged on the foil wrap. The geometry of the foil wrap corresponds in particular to the geometry of the wire winding, with the foil wrap being preferably shorter than the wire winding. The wire winding can cover the entire length of the foil and extend beyond it. The wire winding can also cover the entire width of the foil.

[0012] In the following, the maximum possible effective length is the length of the foil where the foil is present underneath the entire winding. The entire winding is thus applied on an enlarged diameter.

[0013] For example, in a first step, the foil is applied to half of the maximum possible effective length, the winding is then applied, and the inductance of the component is measured. The length of the foil is then reduced or increased for the production of other components, depending on the measured inductance value. Initially applying the foil to only a portion of the maximum possible length (e.g., half) provides flexibility for fine-tuning the foil length.

[0014] The foil in the resulting component does not extend over the entire length of the substrate, for example, in particular, does not extend over the maximum possible effective length of the foil. For example, the foil extends over no more than two-thirds of the length of the substrate, or the maximum possible effective length. Alternatively, the foil extends over at least one-third of the length of the substrate, or the maximum possible effective length. The foil may also extend over the entire maximum possible effective length at the outset or in the tuning component, or there may be no foil.

[0015] Alternatively or additionally, the diameter, and therefore the inductance, can be adjusted by varying the thickness of the foil or the number of foil layers. The foil can be applied to the substrate in one layer. However, to further vary the thickness, the foil can also be applied in multiple layers. For example, to adjust the inductance, a specific number of foil layers can be initially applied, and one or more layers can then be removed or added depending on the measured inductance value. The foil can also have different thicknesses, and the thickness of the foil can be varied for fine-tuning. For example, the foil can always extend to its maximum effective length. Alternatively, a combination of varying the length and varying the number of foil layers or thickness is also possible.

[0016] In one embodiment, the foil is made of a non-magnetic material. For example, this can be a plastic material. The foil can be made of the same material as the coil former. Therefore, the foil only serves to increase the diameter of the coil former and not to guide the magnetic flux.

[0017] The coil former may comprise a recess in which the foil is arranged. The recess is configured for accurate placement of the foil and / or accurate placement of the winding wire.

[0018] For example, the recess is circumferential. In particular, the recess extends helically around the base body. The recess may extend circumferentially around the base body in sections or continuously. For example, the recess may include at least two turns, in particular continuous turns. For example, the recess may extend over at least the entire length of the foil. The recess is preferably designed not only for receiving the foil but also for receiving the winding. The recess preferably extends over a substantial portion of the length of the base body.

[0019] The recess comprises lateral limits, which allow the foil and / or winding to be guided in a non-slip manner perpendicular to its travel in its main direction of extension. The lateral limits can be formed from the material of the base body. In particular, the recess can be formed directly during the manufacture of the base body, for example during injection molding. It is also possible for only one lateral limit to be used for positioning.

[0020] For example, the foil is only slightly wider than the recess. The foil can also have the same width as the recess, or slightly wider than the recess. In this case, the foil can be fixed in the recess by clamping.

[0021] According to another aspect of the present invention, an inductor component includes a coil former as described above and a winding wound around the coil former. In at least some areas, particularly along the length of the winding, a foil is disposed between the winding and the substrate. Consequently, at least some areas of the outer diameter of the coil former, and thus at least some areas of the inner diameter of the winding, are increased. This increases the inductance of the component.

[0022] For example, the winding wire is designed as a flat wire. Alternatively, the winding wire can also be designed as a round wire. It can be a copper wire.

[0023] The inductance of the component is, for example, between 1 and 1000 nH. Depending on the design, the inductance can be adjusted in steps of 0.1% over a range of up to 10% of the inductance, for example, by varying the length of the foil.

[0024] The wire winding preferably extends over the entire length of the foil and, for example, even beyond it. The foil and wire winding are typically configured as two uniform windings positioned one above the other. The wound wire winding is preferably longer than the foil. Thus, the wire winding only covers a portion of the foil in its main extension direction. For example, the ends of the wire winding extend beyond the foil on both sides.

[0025] The wire winding preferably has more turns than the foil. For example, the number of turns of the foil is at most two-thirds the number of turns of the wire winding. For example, the wire winding has eight turns and the foil has five turns. This provides sufficient flexibility for fine-tuning the inductance.

[0026] Thus, the diameter of the winding of wire can be different in different areas. Where the winding of wire is arranged on the foil, the diameter is particularly larger.

[0027] According to one embodiment, the inductor component includes a coil former having a recess, wherein at least some areas of the foil and the winding are arranged in the recess. The recess can be configured as described above for the coil former. The recess can be spiral-shaped and include at least two turns. The winding can be slightly narrower than the recess. The winding can also have the same width as the recess or be slightly wider. In this case, the winding can be fixed in the recess by clamping.

[0028] Alternatively, the foil can be glued to the substrate. For example, the foil can be self-adhesive. The foil can also be attached to the substrate by applying an adhesive. The wire winding can also be glued to the substrate. Alternatively, the foil can be first attached to the wire winding, for example by gluing the foil to the wire winding, and then the wire winding and the foil can be arranged and attached to the substrate.

[0029] Alternatively, the wires and / or foil can be attached to the base body by heat riveting. In this process, after the foil and wires are placed in the recess, pressure and heat are used to expand the radially protruding area of ​​the restriction so that the foil and wires are at least partially radially surrounded by the restriction. Alternatively, the foil can be attached first by gluing, and then the wires can be attached by heat riveting.

[0030] According to another aspect of the present invention, a method for adjusting the inductance of an inductive component is provided. In this method, at least some areas of the base of a coil former are wrapped with foil. The length of the foil is selected based on the target inductance value. For a fixed geometry, the length corresponds to the number of turns of the foil.

[0031] The coil former is then wrapped with the windings so that the foil is arranged between the base body and the windings at least in some regions, in particular along the regions of the windings. The coil former and the inductive component are constructed, for example, as described above.

[0032] For example, to adjust the foil length, the inductance of an inductive component of the same design is measured. Alternatively, the inductance can be measured indirectly, i.e., as a different parameter that is a measure of the inductance. The foil length for another inductive component can then be changed based on the deviation of the measured value from the target value.

[0033] For example, the length is gradually increased or decreased until a desired target value is reached. For example, the number of turns is varied within a range of 1.00 to 4.00 turns. For example, the length is varied in increments less than one turn, such as 0.01 turns.

[0034] According to another aspect of the present invention, a bobbin for an inductive component includes a restricting portion for positioning a winding wire.

[0035] The restriction is particularly designed to guide a section of the winding wire in the central region of the winding; that is, this is a section that is adjacent to at least one other turn of the winding wire on both sides. Therefore, this is not an edge section of the winding. For example, the section is guided on both sides by two restriction sections. The restriction thus forms a recess for accommodating at least one section of the winding wire.

[0036] The restriction or recess typically extends helically around the base of the coil former. For example, the restriction or recess may include at least two turns. The recess may be formed in the base of the coil former. The recess may also be configured to position the foil as described above. However, the coil former may also not include the foil. Otherwise, the coil former may be configured as described above.

[0037] According to another aspect of the present invention, an inductor component includes a coil former having a recess in which a winding wire is disposed. For example, the winding wire is configured as a flat wire. A foil may be disposed between the winding wire and the base of the coil former. Alternatively, such a foil may be absent. The inductor component may be configured differently as described above. The winding wire is attached to the base as described above (e.g., by clamping, gluing, or heat riveting).

[0038] The description of the subject matter provided here is not limited to the individual specific embodiments. Rather, the features of the individual embodiments can be combined with one another within a technically reasonable range. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The objects described here will be explained in more detail below on the basis of schematic design examples.

[0040] The accompanying drawings show:

[0041] Figure 1 An embodiment of a coil former is shown in a side view,

[0042] Figure 2 An embodiment of an inductive component is shown in side view,

[0043] Figures 3A to 3E The method for adjusting the inductance is shown in the schematic diagram. DETAILED DESCRIPTION

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

[0045] Figure 1 A coil former 1 for an inductive component is shown. The coil former 1 is designed as a carrier for a wound wire.

[0046] The coil former 1 is specifically designed for an air-core coil, i.e., a coil without a magnetic core. The coil former 1 is non-magnetic. The coil former 1 may include a base body 2 made of plastic. The coil former 1 is manufactured, for example, using an injection molding process. The inductance of an air-core coil depends largely on the geometry of the winding.

[0047] In an alternative embodiment, the coil former 1 may also be configured as a magnetic core, such as a ferrite core, or the coil former 1 may include a magnetic core.

[0048] In the present case, the base body 2 has a cylindrical shape. The base body 2 can also have a different shape, for example a cuboid shape. The base body 2 can also be part of a larger body (for example a ring body). The base body 2 can be configured as a hollow body.

[0049] Some areas of the base body 2 are wrapped with a foil 3. The foil 3 serves to selectively increase the diameter of the base body 2.

[0050] Foil 3 is thin, which allows fine-tuning of the diameter of base body 2 and, therefore, the inductance of the component after winding the wire onto foil 3. For example, the thickness of foil 3 is between 10 μm and 40 μm. For example, the thickness of foil 3 is 25 μm. In the present case, foil 3 is applied in one layer.

[0051] The foil 3 comprises a non-magnetic material. The foil 3 may comprise a plastic material or be made of a plastic material. The coil former 1 and the foil 3 may, for example, be made of the same material. In other embodiments, the foil 3 may comprise a magnetic material.

[0052] By selectively varying the length of foil 3 corresponding to the number of turns k, the area of ​​increased diameter can be selectively adjusted, thus allowing the inductance of the resulting component to be tuned. In the present case, foil 3 extends over k = 2.00 turns. For example, the number of turns of foil 3 can be varied within the range of k = 1.00 to 4.00 turns. This variation can be performed, for example, in increments of 0.01 turns.

[0053] The coil former 1 further comprises a recess 4 which is configured for precise positioning of the foil 3 and / or the winding 8. The more precisely the foil 3 and / or the winding 8 can be positioned on the coil former 1, the more precisely the inductance of the component can be adjusted.

[0054] The recess 4 extends circumferentially around the base body 2. In particular, the recess 4 extends helically around the base body 2 of the coil former 1. The recess 4 is bounded on two sides perpendicular to the circumferential direction by limits 5 and 6. The limits 5 and 6 also extend around the base body 2. Thus, the recess 4 is configured as a circumferential guide groove / channel. In other words, the recess 4 is configured as a thread, and the limits 5 and 6 are configured as thread flanks.

[0055] The foil 3 is placed in the recess 4. The width of the foil 3 is similar to the width of the recess 4. The foil 3 can be slightly narrower than the recess 4. The foil 3 can also be the same width as the recess 4 or slightly wider and fixed in the recess 4 by clamping or gluing.

[0056] Winding 8 (see Figure 2 ) can also have a width similar to the width of the recess 4. For example, the width b of the recess 4 is at most 25% greater than the width B of the winding.

[0057] The recess 4 comprises n turns, whereby in the present case n = 8. Fewer or more than eight turns are also possible. The recess preferably comprises at least two turns.

[0058] In an alternative embodiment, the coil former 1 does not have a recess 4 for positioning the winding, but has a foil 3 .

[0059] In another alternative embodiment, the coil former 1 has no foil for increasing the diameter, but has recesses 4 for precise positioning of the windings.

[0060] Figure 2 The inductive component 7 is shown, which comprises a coil former 1 and a winding 8 wound around the coil former to form a winding 9. The coil former 1 can be Figure 1 design.

[0061] In the present case, the winding wire 8 is designed as a flat wire. The main surface of the winding wire 8 rests on the base body 2 of the coil former 1. The winding wire 8 can also alternatively be designed as a round wire. For example, this is a copper wire.

[0062] In the present case, the winding 8 comprises m=7.50 turns. The maximum possible effective length of the foil 3 is therefore also 7.50 turns. The winding 8 can also have more or fewer turns.

[0063] The winding 8 comprises two ends 10, 11. The ends 10, 11 continue, for example, to connect the component 7 to contact terminals (not shown) or are provided with further contact connections (not shown).

[0064] Some areas of winding 8 are arranged on foil 3. Foil 3 is therefore arranged between base 2 of coil former 1 and winding 8. In areas where winding 8 is arranged on foil 3, the diameter of winding 9 increases. Therefore, depending on the length or number of turns k of foil 3, winding 8 is arranged on foil 3 in some areas and directly on base 2 in some areas. The diameter D of winding 9 is thus increased only in some areas. The inductance of component 7 increases according to the size of the area with increased diameter.

[0065] The winding 8 is arranged in the recess 4 for precise positioning. The width B of the winding 8 can be only slightly smaller than the width b of the recess 4. The position of the winding 8 is thus precisely determined by the recess 4. The width B of the winding 8 can also be slightly larger than the width b of the recess 2, so that the winding 8 is fixed between the limiting parts 5 and 6 by clamping. The winding 8 can also be fixed in the recess 2 by heat riveting. In particular, the radial end regions of the limiting parts 5 and 6 are widened by heat riveting, so that the winding 8 is at least partially surrounded radially outward by the end regions.

[0066] In one embodiment, the inductive component 6 does not have a recess in the coil former 1 for positioning the winding 8, but has a foil, such as Figure 1 As shown in .

[0067] In the present case, the winding wire 8 is wound onto the coil former 1 in one layer. In other embodiments, the winding wire 8 can also be wound onto the coil former 1 in multiple layers.

[0068] In an alternative embodiment, the inductor component 7 does not have a foil between the base 2 and the winding 8, but instead has a recess 4 for precisely positioning the winding 8. In this case, the diameter D of the winding 9 is uniform. Instead of having two limiting portions 5, 6, the recess 4 can also have only one limiting portion 5, 6 for positioning on one side. Furthermore, the recess 4 or the limiting portions 5, 6 can also be constructed in multiple segments.

[0069] Figures 3A to 3E Method steps for adjusting the inductance of an inductive component are shown.

[0070] according to Figure 3A , a coil frame 1 is provided. The coil frame 1 can be as follows Figure 1 The coil former 1 may, but need not, include a recess 4 .

[0071] according to Figure 3B Based on the input measurement value "M", the length l of the foil 3 is defined, for example, according to a target value. This information can be obtained by measuring the inductance of an identical inductive component. If the measured inductance is less than the desired target value, a foil 3 having a length l longer than the measured component is selected. If the measured inductance is less than the desired target value, a foil 3 having a length l shorter than the measured component is selected.

[0072] For a given coil former 1 and a given winding geometry, the length l of the foil 3 corresponds to the number of turns k. For example, the number of turns k varies in increments of 0.01 turns. For example, the number of turns is adjusted within a range of 1.00 to 4.00 turns.

[0073] according to Figure 3C, the foil 3 is wrapped around the base body 2. In the present case, the number of turns is set to about 2.05. The foil 3 can also be wrapped first and then cut to the required length l. For precise positioning, the coil former 1 can include a spiral recess 4 (see Figure 1 ) and the foil 3 can be placed into the recess 4.

[0074] according to Figure 3D Wire 8 is wound around coil former 1 to form winding 9. Foil 3 selectively increases the diameter D of winding 9, as schematically shown here. The diameter of component 7 varies depending on the thickness of foil 3, particularly in the μm range. In the present case, wire 8 is significantly longer than foil 3. It includes at least one more turn than foil 3. For example, the number of turns of wire 8 is at least one-third greater than the number of turns k of foil 3. This allows for a wide range of inductance adjustment.

[0075] according to Figure 3E After applying the winding 9, a measured value M of the inductance is determined. If the inductance is close enough to the target value, the length l of the foil 3 is defined for a set of components. If the target value has not yet been reached, the length l of the foil 3 is further varied based on the measured value M.

[0076] By adjusting the number of turns of the foil 3, a highly precise adjustment of the inductance of the component 7 can be achieved. For example, depending on the design, the inductance can be adjusted very precisely in increments of 0.1% over a range of up to 10%. For example, the target value of the inductance is between 1 and 1000 nH.

[0077] Reference Signs List

[0078] 1 Coil frame

[0079] 2 Matrix

[0080] 3 foil

[0081] 4 concavity

[0082] 5 Restriction

[0083] 6 Restriction

[0084] 7 Inductor components

[0085] 8. Winding

[0086] 9 Winding

[0087] 10 End of winding wire

[0088] 11 End of winding wire

[0089] b Width of the concave portion

[0090] B Width of winding

[0091] k Number of turns of foil

[0092] n Number of turns in the recess

[0093] m Number of turns of winding

[0094] D Diameter of the winding

[0095] M measurement

Claims

1. Inductor components, including - a coil former, wherein the coil former (1) is designed as a carrier for a winding (8), wherein the coil former (1) comprises a base body (2); - an electrically insulating foil (3), wherein some areas of the base body (2) are wrapped with the electrically insulating foil (3) and thus the electrically insulating foil (3) is wrapped around the base body (2); - a winding (9) consisting of a winding (8) wound around the coil former (1) such that the electrically insulating foil (3) is arranged between the winding (8) and the base body (2), The electrically insulating foil (3) extends over a maximum of two thirds of the maximum possible effective length of the electrically insulating foil (3), so that in some areas the winding (8) is arranged above the electrically insulating foil (3) and in some areas the winding is arranged directly on the base body (2), and so that the diameter of the winding (9) increases in the area where the winding (8) is arranged above the electrically insulating foil (3), wherein The maximum possible effective length is the length of the electrically insulating foil when the electrically insulating foil is present underneath the entire winding (9).

2. The inductor component according to claim 1, The substrate (2) is made of non-magnetic material.

3. The inductor component according to claim 1, The electrically insulating foil (3) is made of a non-magnetic material.

4. The inductor component according to any one of claims 1 to 3, The electrically insulating foil (3) has a maximum thickness of 100 μm.

5. The inductor component according to any one of claims 1 to 3, The coil former (1) comprises a recess (4), wherein the electrically insulating foil (3) is arranged in the recess (4).

6. The inductor component according to claim 5, The recess (4) is spiral and comprises at least two turns.

7. The inductive component according to claim 5, wherein the winding (8) is arranged in the recess (4).

8. The inductive component according to any one of claims 1 to 3, wherein the electrically insulating foil (3) is wrapped helically around the base body (2), and wherein the number of turns (k) of the electrically insulating foil (3) is at most two thirds of the number of turns (m) of the winding (8).

9. A method for setting the inductance value of a group of inductive components of the same design, wherein at least some areas of a base body (2) of a coil former (1) are wrapped with an electrically insulating foil (3) and the electrically insulating foil (3) is thus wrapped around the base body (2), wherein the length of the electrically insulating foil (3) is selected according to the target value of the inductance, and then the coil former (1) is wrapped with a winding (8) so that the electrically insulating foil (3) is arranged between the winding (8) and the base body (2) at least in some areas, and the winding (8) is arranged above the electrically insulating foil (3) in some areas, and the winding is arranged directly on the base body (2), and wherein the inductance of the component (7) is measured after wrapping with the winding (8), and If the target value has not yet been reached, the length of the electrically insulating foil (3) for the further inductive component (7) is changed as a function of the deviation of the measured value from the target value, wherein selecting an electrically insulating foil (3) having a length greater than the component being measured for the further inductive component (7) if the measured inductance is less than the desired target value, or selecting an electrically insulating foil (3) having a length shorter than the component being measured if the measured inductance is greater than the desired target value, Otherwise, if the target value is reached, the length of the electrically insulating foil (3) is defined for the set of inductive components.

10. The method according to claim 9, The electrically insulating foil (3) is wrapped helically around the base body, and the length (l) of the electrically insulating foil (3) varies in steps that are smaller than one turn of the electrically insulating foil (3) around the coil former (1).

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