Inductive component with bare multi wire windings

Abstract

The exemplary embodiments described here relate to an inductive component with an annular magnetic core arranged in a plastic core housing, as well as with electrically insulating separating webs arranged on and protruding from the core housing and dividing a region along (in the circumferential direction) the annular core into several segments, each separating web having a recess. The component further comprises (at least) one winding formed from several non-insulated individual wires with several turns, the individual wires being wound together around the core housing such that one turn is arranged in each segment and the individual wires are guided through the recess in one of the separating webs into an adjacent segment after each turn.

Description

TECHNICAL FIELD

[0001] The present description relates to an inductive component with a ring-shaped magnetic core. BACKGROUND

[0002] Inductive components are passive electrical or electronic devices in which a soft magnetic core is typically wound around a conductive wire. The soft magnetic core and the conductive wire must be electrically insulated from each other. Furthermore, the individual turns of a winding must be insulated from each other to prevent short circuits between adjacent turns. This is typically achieved by applying an insulating coating to the conductive wire (usually with a varnish). Additionally, the core can be installed in an insulating housing, which also serves as mechanical protection for the soft magnetic core. Such a housing is called a core casing.

[0003] Chokes are an important type of inductive component. Chokes are used, among other things, to suppress interference pulses. Chokes can have a ring-shaped magnetic core. Commonly used for current-compensated chokes, for example, are ring-shaped magnetic cores with a core housing.

[0004] The design of inductive components with a toroidal magnetic core is subject to a variety of boundary conditions. To achieve high inductances, the winding is usually carried out on a magnetic core with medium or high permeability, which, however, should be as small as possible due to a wide variety of installation conditions. EP 2 200 052 B1 describes a current-compensated choke in which the lead wire is guided around the core through the inner hole of the core housing. The core housing serves both as an insulator and as stable protection for the magnetic core, as the core housing absorbs the tensile forces when the wire is applied and prevents direct force from acting on the magnetic core. The core housing therefore requires a material with high strength. A common core housing material is plastic. Due to the limited strength of plastic, for example, relatively thick walls are necessary.

[0005] When winding thicker wires, the greater winding tension results in high mechanical stress on the core housing. To ensure a tight fit between the wires and the core housing, the wire must be pulled taut as it passes through the core housing. The forces acting during this process are largely absorbed by the core housing edges. For example, current-compensated chokes often feature highly permeable cores made of nanocrystalline alloys for optimized solutions with small volumes. The magnetic core must also be protected from forces due to magnetostriction.

[0006] In DE 102018 112 975 A1, this problem is solved by assembling the individual turns of a winding from several parts (clips). During assembly, the U-shaped clips, for example, are placed on the annular core housing and connected to each other. This prevents mechanical stress on the core during winding. However, this is a more complex process, especially for small batches.

[0007] For conventional plastic housings with wall thicknesses of 1-2 mm, the possibilities for winding toroidal cores end with wire gauges of 1.5-2.5 mm copper wire. To use thicker wires, either new, significantly stronger plastic housings must be designed and built, or a different technique for winding or applying the windings must be used.

[0008] An alternative is the use of twisted thin wires (HF strands), which in principle solve the problem of limiting tensile forces, but have other disadvantages such as poorer high-frequency behavior due to the increased capacitance between the turns, higher wire costs and higher costs for the connection technology.

[0009] A winding technology would be desirable in which the core housing has to absorb significantly lower winding forces without deforming or transferring the forces to the magnetic core, while at the same time being suitable for winding with thicker wires. Furthermore, it should offer advantageous high-frequency properties.

[0010] The inventors have set themselves the task of creating a new technique for producing a winding of an inductive component which avoids or at least partially mitigates the problems described above. SUMMARY

[0011] The above-mentioned object is achieved by an inductive component according to claim 1. Various embodiments and further developments are the subject of the dependent claims.

[0012] One embodiment relates to an inductive component with an annular magnetic core arranged in a plastic core housing, as well as with electrically insulating separating webs arranged on and protruding from the core housing, which divide a region along (in the circumferential direction) the annular core into several segments, each separating web having a recess. The component further comprises (at least) one winding formed from several non-insulated individual wires with several turns, wherein the individual wires are wound together around the core housing such that one turn is arranged in each segment and the individual wires are guided through the recess in one of the separating webs into an adjacent segment after each turn.

[0013] In one embodiment, at least two separating webs connected to each other via a carrier plate form a segment separating element arranged on the core housing. The individual wires can be coated with a corrosion-resistant, electrically conductive material. In one embodiment, the individual wires are made of copper and coated with tin. The bare individual wires can be twisted. In some embodiments, the individual wires are at least partially soldered to each other.

[0014] In one embodiment, each separating web protrudes perpendicularly from the core housing, particularly in both axial directions and inwardly in the radial direction (toward the center of the toroidal core). The separating webs can be integral components of the core housing. Alternatively, the segment separating element can be plugged onto the core housing or glued to the core housing.

[0015] In one embodiment, the at least one segment separator is designed to be collapsible and, in particular, comprises two parts connected to one another via a hinge (e.g., a foil hinge). The segment separator can be arranged unfolded along the inner circumference of the toroidal core. It may be sufficient for the at least one segment separator to be fixed to the toroidal core only by means of the individual wires.

[0016] The toroidal core can be a toroidal tape-wound core, for example, and the magnetic core of the toroidal core can be made of an amorphous or nanocrystalline alloy. The toroidal core can have a magnetic permeability of 40,000 or more. The inner diameter of the toroidal core can be 5 mm or more, and the individual wires can have a diameter of 1 mm or more. The ends of the lead wires can be twisted together to form individual contacts. BRIEF DESCRIPTION OF THE ILLUSTRATIONS

[0017] Various embodiments are explained in more detail below with the aid of illustrations. The illustrations are not necessarily to scale, and the invention is not limited to the aspects shown. Rather, emphasis is placed on illustrating the principles underlying the illustrated embodiments. Figure 1 shows a throttle body according to the invention in an oblique view. Figure 2 shows a wound throttle body according to the invention in plan view. Figure 3 shows a segment separating element according to the invention. Figure 4 shows a throttle body according to the invention in an oblique view with several segment separating elements. Figure 5 shows a foldable segment separating element according to the invention. DETAILED DESCRIPTION

[0018] The exemplary embodiments described here enable a simple construction of an inductive component with a ring-shaped magnetic core, particularly allowing the winding of the core housing with thicker wire diameters while simultaneously achieving advantageous high-frequency properties. The forces acting on the core housing during winding are kept comparatively small. The construction described here is particularly suitable for inductive components with a highly permeable core, which are generally sensitive to mechanical influences.

[0019] Fig. 1shows an example of an unwound choke body 101 in an oblique view. The choke body 101 comprises a toroidal core 10 and an annular core housing 11, which completely encloses the toroidal core 10. In this exemplary embodiment, the toroidal core 10 has a rectangular cross-sectional area. Depending on the application, the toroidal core 10 can have an air gap. However, other cross-sectional shapes are also possible. The core housing 11 consists of an electrically insulating material, e.g., plastic. The toroidal core 10 does not necessarily have a circular contour. In general, any magnetic core that follows a closed contour (e.g., a polygon, an ellipse, an oval, etc.) is referred to as a toroidal core. The inner diameter (for circular toroidal cores) is often over 5 mm. The magnetic core is usually made of soft magnetic material and can be designed as a toroidal strip core. The toroidal strip core can, for example,They are made of an amorphous or nanocrystalline alloy. The magnetic core often has a magnetic permeability of over 40,000.

[0020] In the example shown, at least one segment separator 102 is plugged onto the core housing 11. In the example shown, the segment separator 102 has two separating webs 21 that define two segments along the circumference of the toroidal core, with one turn of the winding located in each segment after the toroidal core has been wound. The number of segments (and thus the number of separating webs 21) therefore corresponds to the number of turns. The separating webs 21 protrude from the core housing 11 in the radial direction (from the inner surface inwards) and in the axial direction (from the upper and lower cover surfaces upwards or downwards). Each separating web 21 can have a recess 23 through which the winding wires can be passed from one segment to the next segment. In the example shown, the recesses 23 are located on the upper side of the core housing 11 (although this does not necessarily have to be the case).

[0021] In the example shown, the segment separating element 102 is plugged onto the core housing, i.e., positively connected to the core housing 11. For this purpose, the segment separating element 102 has a carrier plate 22 (connecting plate) on which the separating webs 21 are arranged and which has a shape that is complementary to the shape of the core housing, so that the carrier plate 22 can be plugged onto the core housing. In the example shown, the carrier plate extends along the inner circumferential surface and also along the upper and lower cover surfaces of the core housing 11. This means that the carrier plate 22 has a U-shaped cross-sectional area (when cut in the diametrical direction). The core housing 11 and the carrier plate 22 of the segment separating element 102 can also be designed such that the carrier plate 22 snaps into place on the core housing 11 when plugged onto the core housing (snap-in connection).

[0022] The segment separating element 102 does not have to be a separate component. The separating webs 21 with recesses 23 can also be an integral part of the toroidal core housing 11. The carrier plates 22 could then be omitted, since they primarily serve to fasten the separating webs 21 to the toroidal core housing 11. This means that the housing wall of the core housing 11 itself functions as a carrier plate. The separating webs 21 and the carrier plates 22 are usually made of plastic. For the production of a segment separating element 102, for example, an injection molding process would be suitable. The injection molding process would also be a simple variant for the production of a core housing 11 with integrated separating webs 21. The separating webs 21 do not necessarily have to extend in three directions (upwards, downwards, and inwards). It would also be possible to only provide the radially inward-facing part of the separating web with an axially pronounced (e.g.The upward-facing part of the separator should be designed with the recess, and the axially opposite part (e.g., the downward-facing part) should be omitted. The separator would then have an L-shape. The recess 23 is optional, but can improve the routing of the winding wires.

[0023] Fig. 2shows an example of a wound coil former 103 according to the invention in a plan view. On the toroidal core (more precisely on the core housing 11) there are several segment separating elements 102 arranged in a row, which have several separating webs 21 with recesses 23. As explained above, the separating webs can be arranged on a carrier plate 22. The segment separating elements 102 enclose approximately half of the toroidal core 10. In some embodiments, several segment separating elements are arranged next to one another on a toroidal core in order to cover a larger part of the toroidal core 10 and to facilitate assembly. Alternatively, the separating webs 21 could also be an integral part of the housing 11 of the toroidal core 10. It is understood that the windings can extend around the entire toroidal core, even if in the example from Fig. 2only half of the toroidal core is wound. In the case of current-compensated chokes, two windings are usually arranged on the core. In the example shown, the toroidal core 10 is wound with two individual wires 31a and 31b. The individual wires 31a and 31b are bare (i.e., uninsulated) wires that touch each other several times. It is understood that more than two individual wires can be used. Merely for the sake of simplicity, Fig. 2 only two individual wires are shown.

[0024] The area along the toroidal core 10 between two separating webs 21 forms a segment, i.e., each separating web separates two adjacent segments. The segment separating element 102 thus divides the toroidal core into several segments along its circumference. The two individual wires 31a and 31b are wound together around the toroidal core 10 such that together they form exactly one turn in each segment. After forming one turn, the individual wires 31a and 31b are guided into the adjacent segment via the recesses 23. The recesses 23 thus serve the purpose of enabling the individual wires 31a and 31b to be guided into the adjacent segment. The segment separating element 102 can be glued or simply plugged onto the toroidal core 10. The segment separating element 102 can also be fixed to the toroidal core 10 only by the winding itself, whereby the turns of the individual wires 31a and 31b press the segment separating element 102 firmly onto the toroidal core 10.

[0025] By winding the individual wires together, there are numerous electrically conductive contact surfaces between the individual wires in each segment, which is why the individual wires act like a single thick wire. To achieve even better contact between the individual wires, they can be soldered together within the winding. This is not absolutely necessary, however. The individual wires can also be twisted together to ensure good contact between the uninsulated individual wires. The individual wires thus have almost the same properties in the high-frequency range as a single, thicker wire. Using two or more electrically insulated individual wires, on the other hand, would lead to adverse capacitive effects between the individual wires and to reduced attenuation in the high-frequency range. Using multiple individual wires also reduces the forces acting on the core housing during winding.This combines the advantageous properties of a winding that acts like a single wire in the high-frequency range and significantly reduces the forces generated by winding. The resulting wire cross-section from the individual wires can be of any size and is limited only by the inner diameter of the toroidal core and the number of turns.

[0026] The thinner the wires and the more individual wires used, the more the fill factor deteriorates, meaning the utilization of the available winding space and thus the achievable cross-section are reduced. The use of arbitrarily thin wires is therefore not advantageous. The inventive design allows a few, thicker wires to be used to achieve the highest possible fill factor. Negative high-frequency characteristics are minimal, and the forces on the toroidal core caused by the winding are significantly reduced.

[0027] Due to the use of individual wires without an insulating coating, the electrical insulation of the individual wires between the individual turns must be achieved in a different way. This is the primary function of the insulating separators 21, which prevent contact between the individual wires between two adjacent turns and thus a short circuit. Copper is usually used as the material for the individual wires. The individual wires can have a diameter of over 1 mm. To ensure permanently good contact between the individual wires, the individual wires can be made more corrosion-resistant. The surface of the individual wires can, for example, be provided with a protective coating or a galvanically or hot-dip tinned layer of a metal with little tendency to oxidation, e.g. tin. The use of more precious metals such as silver, gold or palladium is also possible.It is important that the coating is electrically conductive, otherwise there will be no electrical contact between the individual wires within a segment.

[0028] Fig. 3 shows an example of a single segment separating element 102 in an oblique view. Such a Fig. 1 arranged on the toroidal core 10. The segment separating element 102 comprises two separating webs 21a and 21b with recesses 23 and two carrier plates 22a and 22b. However, it can be arranged as in Fig. 2A segment separating element can also consist of more than two separating webs 21 with corresponding connecting plates 22. In the example shown, the segment separating element 102 has two separating webs 21a and 21b, which are connected by the carrier plate 22a. The carrier plate 22b can be seen as an extension of the carrier plate 22a on the other side of the separating web 21b, so that the separating web 21b is located between the carrier plate 22a and the carrier plate 22b. The two carrier plates 22a and 22b have the same spatial dimensions and can also be seen as parts of a carrier plate.

[0029] Fig. 4 shows an unwound choke body 104 in an oblique view, with two segment separating elements 102a and 102b arranged side by side on the toroidal core 10. The example from Fig. 4 differs from only from Fig. 1merely in that the throttle body 104 has a second segment separating element 102. The two segment separating elements 102a and 102c each correspond to the Fig. 3 described segment separating element 102. The two segment separating elements 102a and 102c are positioned next to one another on the toroidal core 10 such that the carrier plate 22b of the segment separating element 102a forms a positive connection with the separating web 21c of the segment separating element 102c. Since the segment separating elements 102a and 102c have the same size, the segments between the separating webs 21 are always the same size. Additional segment separating elements 102 could be applied to the throttle body 104 so that it is completely subdivided into equally sized segments by the segment separating elements 102. As already mentioned, the segment separating elements 102a and 102c can also be an integral part of the core housing 11. The carrier plates 22 are then formed by the wall of the core housing 11.

[0030] Segment separators can be manufactured according to their desired application, e.g., with different distances between their separators, i.e., larger or smaller segments. Furthermore, the height of the separators can be varied to enable different winding heights. The ability to attach segment separators to the core housing 11 means that existing toroidal core housings can be fitted with them without modification. Different segment separators can be used to produce different windings, differing, for example, in the number of turns or the cross-section of the turn. Depending on the application, the segments of a toroidal core can be adapted to various requirements and then wound accordingly.

[0031] Fig. 5shows a plan view of a foldable segment separating element 105. The foldable segment separating element 105 consists of two or more segment separating elements 102, as shown, for example, in the Fig. 3 The arrangement of the two segment separating elements 102a and 102c relative to each other is analogous to Fig. 4 , where the toroidal core is Fig. 5 not shown. The two segment separating elements 102a and 102c are connected via a film hinge 24 (not shown in detail). The film hinge is attached to radially inner points of the separating web 21c and the support plate 22b. When the film hinge 24 is folded, an angle θ opens between the separating web 21c and the support plate 22b.

[0032] The foldable segment separating element 105 can be mounted on a toroidal core housing 11, wherein the inner radius of the toroidal core housing 11 is slightly larger than the radius of curvature of the support plates 22. For this purpose, the foldable segment separating element 105 is inserted into the inner hole of the toroidal core 10 in the folded state and then folded open to mount it on the toroidal core housing 11 such that the support plate 22 rests against the outer surface of the core housing (and possibly snaps into place thereon). This is advantageous for toroidal cores with a large winding height, i.e. a large difference between the inner and outer diameters. Of course, other hinges such as a folding hinge or other flexible elements can also be used to make the segment separating element 105 foldable.

[0033] Some of the exemplary embodiments described here are summarized below. It is understood that the following is not a complete list, but merely an example. The reference numerals in parentheses refer to Fig. 1 to 5 .

[0034] Example 1: An inductive component that has the following: an annular magnetic core (10) arranged in a core housing (11) made of plastic; electrically insulating separating webs (21) which are arranged on the core housing (11) and protrude therefrom and which divide an area along the annular core (10) into a plurality of segments, each separating web (21) having a recess (23); a winding formed from a plurality of non-insulated individual wires (31a, 31b) with a plurality of turns, the individual wires (31a, 31b) being wound together around the core housing (11) in such a way that one turn is arranged in each segment and the individual wires (31a, 31b) are guided through the recess (23) in one of the separating webs (21) into an adjacent segment after each turn.

[0035] Example 2: The inductive component according to Example 1, wherein at least two separating webs (21) connected to one another via a carrier plate (22) form a segment separating element (102, 105) which is arranged on the core housing (11).

[0036] Example 3: The inductive component according to example 1 or 2, wherein the individual wires (31a, 31b) are coated with a corrosion-resistant electrically conductive material.

[0037] Example 4: The inductive component according to example 1 or 2, wherein the individual wires (31a, 31b) are made of copper and coated with tin.

[0038] Example 5: The inductive component according to example 1 or 2, wherein the individual wires (31a, 31b) are twisted.

[0039] Example 6: The inductive component according to one of examples 1 to 5, wherein each separating web (21) projects perpendicularly from the core housing (11), in particular in both axial directions and inwards in the radial direction.

[0040] Example 7: The inductive component according to one of examples 1 to 6, wherein the individual wires (31a, 31b) are at least partially soldered to one another.

[0041] Example 8: The inductive component according to one of examples 1 to 7, wherein the separating webs (21) are integral components of the core housing (11).

[0042] Example 9: The inductive component according to one of examples 1 to 7, wherein the at least one segment separating element (102, 105) is plugged onto the core housing (11).

[0043] Example 10: The inductive component according to one of examples 1 to 7, wherein the at least one segment separating element (102, 105) is adhesively bonded to the core housing (11).

[0044] Example 11: The inductive component according to example 9 or 10, wherein the at least one segment separating element (102, 105) is foldable and in particular comprises two parts connected to one another via a hinge.

[0045] Example 12: The inductive component according to Example 11, wherein the segment separating element (102, 105) is arranged unfolded along the inner circumference of the toroidal core (10).

[0046] Example 13: The inductive component according to example 9 or 12, wherein the at least one segment separating element (102, 105) is fixed to the toroidal core (10) only via the individual wires (31a, 31b).

[0047] Example 14: The inductive component according to one of examples 1 to 13, wherein the toroidal core (10) is a toroidal band core.

[0048] Example 15: The inductive component according to one of examples 1 to 14, wherein the magnetic core of the toroidal core (10) consists of an amorphous or nanocrystalline alloy.

[0049] Example 16: The inductive component according to one of examples 1 to 15, wherein the inner diameter of the toroidal core (10) is at least 5 mm.

[0050] Example 17: The inductive component according to one of examples 1 to 16, wherein the individual wires (31a, 31b) have a diameter of more than 1 mm.

[0051] Example 18: The inductive component according to one of examples 1 to 17, wherein the toroidal core (10) has a magnetic permeability greater than 40000.

[0052] Example 19: The inductive component according to any one of examples 1 to 18, wherein the ends of the lead wires are twisted so that the ends of the lead wires form individual contacts.

Claims

1. An inductive component comprising: an annular magnetic core (10) arranged in a core housing (11) made of plastic; electrically insulating separating webs (21) which are arranged on the core housing (11) and protrude therefrom and which divide a region along the annular core (10) into a plurality of segments, each separating web (21) having a recess (23); a winding formed from a plurality of uninsulated individual wires (31a, 31b) with a plurality of turns, the individual wires (31a, 31b) being wound together around the core housing (11) in such a way that one turn is arranged in each segment and the individual wires (31a, 31b) are guided through the recess (23) in one of the separating webs (21) into an adjacent segment after each turn.

2. The inductive component according to claim 1, wherein at least two separating webs (21) connected to one another via a carrier plate (22) form a segment separating element (102, 105) which is arranged on the core housing (11).

3. The inductive component according to claim 1 or 2, wherein the individual wires (31a, 31b) are coated with a corrosion-resistant electrically conductive material.

4. The inductive component according to claim 1 or 2, wherein the individual wires (31a, 31b) are made of copper and coated with tin.

5. The inductive component according to claim 1 or 2, wherein the individual wires (31a, 31b) are twisted.

6. The inductive component according to claim 1 to 5, wherein each separating web (21) protrudes perpendicularly from the core housing (11).

7. The inductive component according to claim 6, wherein each separating web (21) projects in both axial directions and inwardly in the radial direction.

8. The inductive component according to claim 1 to 7, wherein the individual wires (31a, 31b) are at least partially soldered together.

9. The inductive component according to claim 1 to 8, wherein the separating webs (21) are integral components of the core housing (11).

10. The inductive component according to claim 1 to 8, wherein the at least one segment separating element (102, 105) is plugged onto the core housing (11).

11. The inductive component according to claim 1 to 8, wherein the at least one segment separating element (102, 105) is glued to the core housing (11).

12. The inductive component according to claim 10 or 11, wherein the at least one segment separating element (102, 105) is collapsible.

13. The inductive component according to claim 12, wherein the at least one segment separating element (102, 105) comprises two parts connected to one another via a hinge.

14. The inductive component according to claim 12 or 13, wherein the segment separating element (102, 105) is arranged unfolded along the inner circumference of the toroidal core (10).

15. The inductive component according to claim 8 or 14, wherein the at least one segment separating element (102, 105) is fixed to the toroidal core (10) only via the individual wires (31a, 31b).

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