Patent Description:
State of the inductor coils use flat helical wound copper or ribbon shaped windings for high current applications. This leads to low values of direct current resistance (DCR). This has great benefits, but a significant disadvantage relating to AC losses within the flat wound element of the coil.

<CIT> describes that a reactor includes a coil formed by spirally winding a wire and a magnetic core having an inside core portion inserted into the coil and an outside core portion coupled to the inside core portion. It is described that these core portions form a closed magnetic circuit, that the coil is covered with an inside resin portion on the outer circumference thereof to form a coil molded unit with its shape being held, that the outer circumference of a combination unit of the coil molded unit and the magnetic core is covered with an outside resin portion, that the reactor does not have a case and is thus compact.

<CIT> describes that a reactor includes one coil formed by spirally winding a wire, and a magnetic core, which is disposed inside and outside the coil and which forms a closed magnetic circuit. It is described that the magnetic core includes an inner core portion disposed inside the coil, and an outer core portion disposed around the coil, that the coil and the inner core portion constitute a coil component held as an integral unit by a resin molded portion. It is described that a shape of the coil is maintained by the resin molded portion.

<CIT> describes that a reactor includes a core, a covering member, and a conductor. It is described that the core is made of a magnetic material and has a plurality of blocks arranged via a magnetic gap, that the covering member is made of a nonmagnetic material having electrical insulation properties and covers the magnetic gap, and that the conductive wire is coiled around at least one block of the plurality of blocks and the covering member.

<CIT> describes a reactor coil for electronic fluorescent lamp ballast units, in which the radio-frequency braiding and the insulating impregnation which are otherwise required can be omitted by suitable design of the coil body.

<CIT> and JPS60242609A each disclose inductors in which a coil is inserted into a core made up from two core halves and is compressed by and between the two core halves.

To achieve low a DCR, a thicker flat copper foil ><NUM> is used. This however amplifies any high frequency (HF) AC losses within the coil by anywhere from <NUM>-<NUM> times the normal DC losses.

There is another problematic effect that is associated with coils with such high power density, and this is due to the large gap in the core of the coil that is required to achieve desirable maximum saturation currents. Larger magnetic gaps result in larger fringing fields, and any permeable material placed close to the magnetic gap will incur eddy losses. This in turn causes areas of significant temperature rises with both stranded and flat ribbon wound coils. Some existing methods try to solve this issue by using bobbin shapes to avoid temperature hot spots, but this results in a reduction in cross sectional area that would could otherwise be utilised for copper, and also reduces the thermal performance of the coil. Other methods use a distributed gap in the core to reduce the fringing field, but this adds significant cost to the manufacturing costs.

It would be advantageous to have an improved inductor coil.

Claim <NUM> defines an inductor coil. Claim <NUM> defines an inductor coil. Claim <NUM> defines a method of forming an inductor coil. Claim <NUM> defines a method of forming an inductor coil. The invention and its scope of protection is defined by these independent claims. The following aspects and examples of the disclosure provide examples on how technical subject matters can be combined.

In a first aspect, that is according to the invention, there is provided an inductor coil, comprising:.

The first component is located adjacent to the second component. A core is formed from the first component and the second component. The core is located along a first portion of a central axis and a second portion of the central axis. Along a third portion of the central axis the first component is spaced from the second component to form a gap in the core. The third portion of the central axis is between the first portion of the central axis and the second portion of the central axis. A first part of the length of conductor is located around the first portion of the central axis, located around the second portion of the central axis, and located around the third portion of the central axis to form a plurality of turns of conductor around the core and the gap in the core. At least one section of the first part of the length of conductor is compressed in the direction of the central axis.

In this manner, the coil with a compressed conductor can achieve lower or equal DCR than existing coils, but at the same time the AC losses rather than being <NUM>-<NUM> times the DC losses now only amount to <NUM>-<NUM> times the DC losses.

In an example, a second part and a third part of the length of conductor at the ends of the length of conductor form part of connection terminals of the inductor coil.

In an example, the whole of the first part of the length of the conductor is compressed.

In an example, the at least one section of the first part of the length of conductor that is compressed has a dimension of the conductor in the direction of the central axis that is less than a dimension of the conductor in a direction perpendicular to the central axis.

According to the invention, at least one section of the first part of the length of conductor between a base portion of the first component and a base portion of the second component is compressed between and by the base portion of the first component and the base portion of the second component.

By compressing the conductor during assembly of the inductor coil mitigates putting tension in the wire for wire that has already been fully compressed, and that is then would around the core. The wire can however be partially compressed prior to being wound around and/or located around the core, and then further compressed as the first and second components are brought together and further compressing the conductor.

In an example, the whole of the first part of the length of conductor can be compressed prior to being located around the core and gap in the core. In an example, the first and second base portions can have base portions that only extend laterally over a certain angular range. Then the first part of the length of the conductor can be located around the core and gap in the core, and then the base portions of the first and second parts are moved toward each other and then the length of the conductor over these angular ranges can then be further compressed by the base portions.

In an example, the first part of the length of the conductor can be located around the core and the gap in the core, and then the base portions of the first and second parts are moved toward each other and only the conductor at the angular positions where the base portions face one another is compressed.

In an example, the first part of the length of conductor is at least partially compressed prior to being located around the first portion of the central axis, located around the second portion of the central axis, and located around the third portion of the central axis.

In an example, adjacent turns of the plurality of turns of conductor are bonded to each other.

This for example, facilitates prior compression of the first part of the length of conductor before it is located around the core gap in the core of the inductor coil, parts of the conductor turns may then not be under compression between the base portions of the first component and second component, but remain in a compressed tight arrangement.

According to the invention, each turn of conductor of the plurality of turns of conductor has an inner part of the conductor spaced at least one distance from the central axis in a direction perpendicular to the central axis. The inner part of the conductor of two or more turns of the conductor located around the first portion of the central axis and/or located around the second portion of the central axis is/are spaced from the central axis by at least one first distance. The inner part of the conductor of one or more turns of the conductor located around the third portion of the central axis is spaced from the central axis by at least one second distance greater than the at least one first distance.

In other words, the turns of the conductor at the position of the gap in the core are spaced further from axis of the inductor coil than the other turns around the core. This can be through either displacement of the turns sideways, or deformation of the inner part of the conductor turns facing the axis of the inductor coil. In this manner, the inductor coil does not lead to induced eddy currents that would otherwise be caused by conductive material being present in these fringing fields. This avoids temperature hotspots, maximises the available cross-sectional area of conductor, and maximises the thermal performance of the coil.

In an example, a spacer is located in the gap in the core to form a gap around the core. An outer surface of a portion of the spacer is located a distance from the central axis that is greater than a distance from the central axis of an outer surface of the first component and an outer surface of the second component that form the core.

In other words, the spacer is positioned in the gap in the core, and is wider than the diameter of the core, and when the first part of the length of conductor is located around the core and gap in the core, the spacer forms a space around the outer extent of the gap in the core, by either in effect pushing conductor turns sideways, and/or deforming the inner part of each conductor turn at the location of the gap in the core.

In an example, a dimension of the portion of the spacer adjacent to the outer surface of the first component and the outer surface of the second component in the direction of the central axis is greater than a dimension of the gap in the core in the direction of the central axis.

In an example, the outer surface of the portion of the spacer is configured to contact the one or more turns of conductor located around the third portion of the central axis.

In an example, the spacer comprises a non-conductive material.

In an example, the spacer comprises a central hole configured to be located around the central axis.

In an example, the first component comprises a ferrite material.

In an example, the second component comprises a ferrite material.

In an example, the conductor comprises a multi-strand wire.

In an example, the conductor comprises a Litz wire.

In a second aspect, that is according to the invention, there is provided an inductor coil, comprising:.

The first component is located adjacent to the second component. A core is formed from the second component. The core is located along a first portion of a central axis. Along a second portion of the central axis the first component is spaced from the second component to form a gap in the core. The second portion of the central axis is between the first portion of the central axis and the first component. A first part of the length of conductor is located around the first portion of the central axis, and located around the second portion of the central axis to form a plurality of turns of conductor around the core and the gap in the core. At least one section of the first part of the length of conductor is compressed in the direction of the central axis.

In this manner, the compressed coil can achieve lower or equal DCR than existing coils, but at the same time the AC losses rather than being <NUM>-<NUM> times the DC losses now only amount to <NUM>-<NUM> times the DC losses.

In an example, the whole of the first part of the length of conductor can be compressed prior to being located around the core and gap in the core. In an example the first and second base portions can have base portions that only extend laterally over a certain angular range. Then the first part of the length of the conductor can be located around the core and gap in the core, and then the base portions of the first and second parts are moved toward each other and then the length of the conductor over these angular ranges can then be further compressed by the base portions.

In an example the first part of the length of the conductor can be located around the core and the gap in the core, and then the base portions of the first and second parts are moved toward each other and only the conductor at the angular positions where the base portions face one another is compressed.

In an example, the first part of the length of conductor is at least partially compressed prior to being located around the first portion of the central axis, and located around the second portion of the central axis.

This for example, facilitates prior compression of the first part of the length of conductor before it is located around the core gap in the core of the inductor coil, parts of the conductor turns may not then be under compression between the base portions of the first component and second component, but remain in a compressed tight arrangement.

According to the invention, each turn of conductor of the plurality of turns of conductor has an inner part of the conductor spaced at least one distance from the central axis in a direction perpendicular to the central axis, wherein the inner part of the conductor of two or more turns of the conductor located around the first portion of the central axis is spaced from the central axis by at least one first distance, and wherein the inner part of the conductor of one or more turns of the conductor located around the second portion of the central axis is spaced from the central axis by at least one second distance greater than the at least one first distance.

In an example, a spacer is located in the gap in the core to form a gap around the core. An outer surface of a portion of the spacer is located a distance from the central axis that is greater than a distance from the central axis of an outer surface of the second component that forms the core.

In an example, a dimension of the portion of the spacer adjacent to the outer surface of the second component in the direction of the central axis is greater than a dimension of the gap in the core in the direction of the central axis.

In an example, the outer surface of the portion of the spacer is configured to contact the one or more turns of conductor located around the second portion of the central axis.

In a third aspect according to the invention, there is provided an inductor coil, comprising:.

The first component is located adjacent to the second component. A core is formed from the first component and the second component. The core is located along a first portion of a central axis and a second portion of the central axis. Along a third portion of the central axis the first component is spaced from the second component to form a gap in the core. The third portion of the central axis is between the first portion of the central axis and the second portion of the central axis. A first part of the length of conductor is located around the first portion of the central axis, located around the second portion of the central axis, and located around the third portion of the central axis to form a plurality of turns of conductor around the core and the gap in the core. Each turn of conductor of the plurality of turns of conductor has an inner part of the conductor spaced at least one distance from the central axis in a direction perpendicular to the central axis. The inner part of the conductor of two or more turns of the conductor located around the first portion of the central axis and/or located around the second portion of the central axis is/are spaced from the central axis by at least one first distance. The inner part of the conductor of one or more turns of the conductor located around the third portion of the central axis is spaced from the central axis by at least one second distance greater than the at least one first distance.

According to the invention, at least one section of the first part of the length of conductor is compressed in the direction of the central axis.

Compressing the conductor during assembly of the inductor coil mitigates putting tension in the wire for wire that has already been fully compressed, and that is then would around the core. The wire can however be partially compressed prior to being wound around and/or located around the core, and then further compressed as the first and second components are brought together and further compressing the conductor.

In a fourth aspect according to the invention, there is provided an inductor coil, comprising:.

The first component is located adjacent to the second component. A core is formed from the second component. The core is located along a first portion of a central axis. Along a second portion of the central axis the first component is spaced from the second component to form a gap in the core. The second portion of the central axis is between the first portion of the central axis and the first component. A first part of the length of conductor is located around the first portion of the central axis, and located around the second portion of the central axis to form a plurality of turns of conductor around the core and the gap in the core. Each turn of conductor of the plurality of turns of conductor has an inner part of the conductor spaced at least one distance from the central axis in a direction perpendicular to the central axis. The inner part of the conductor of two or more turns of the conductor located around the first portion of the central axis is spaced from the central axis by at least one first distance. The inner part of the conductor of one or more turns of the conductor located around the second portion of the central axis is spaced from the central axis by at least one second distance greater than the at least one first distance.

In, and example the first part of the length of the conductor can be located around the core and the gap in the core, and then the base portions of the first and second parts are moved toward each other and only the conductor at the angular positions where the base portions face one another is compressed.

In a fifth aspect, that is according to the invention, there is provided a method of forming an inductor coil, comprising:.

According to the invention, the method comprises compressing at least one section of the first part of the length of conductor between a base portion of the first component and a base portion of the second component.

In an example, the method comprises at least partially compressing the first part of the length of conductor prior to locating it around the first portion of the central axis, around the second portion of the central axis, and around the third portion of the central axis.

In an example, the method comprises bonding adjacent turns of the plurality of turns of conductor to each other.

According to the invention, the method comprises locating the length of conductor such that each turn of conductor of the plurality of turns of conductor has an inner part of the conductor spaced at least one distance from the central axis in a direction perpendicular to the central axis. The inner part of the conductor of two or more turns of the conductor located around the first portion of the central axis and/or located around the second portion of the central axis is/are spaced from the central axis by at least one first distance. The inner part of the conductor of one or more turns of the conductor located around the third portion of the central axis is spaced from the central axis by at least one second distance greater than the at least one first distance.

In an example, the method comprises locating a spacer in the gap in the core to form a gap around the core. An outer surface of a portion of the spacer is located a distance from the central axis that is greater than a distance from the central axis of an outer surface of the first component and an outer surface of the second component that form the core.

In an example, the method comprises contacting the outer surface of the portion of the spacer with the one or more turns of conductor located around the third portion of the central axis.

In a sixth aspect, that is according to the invention, there is provided a method of forming an inductor coil, comprising:.

In an example, the at least one of the first part of the length of conductor that is compressed has a dimension of the conductor in the direction of the central axis that is less than a dimension of the conductor in a direction perpendicular to the central axis.

According to invention, the method comprises compressing at least one section of the first part of the length of conductor between a base portion of the first component and a base portion of the second component.

In an example, the method comprises at least partially compressing the first part of the length of conductor prior to locating it around the first portion of the central axis, and around the second portion of the central axis.

According to the invention, the method comprises locating the length of conductor such that each turn of conductor of the plurality of turns of conductor has an inner part of the conductor spaced at least one distance from the central axis in a direction perpendicular to the central axis. The inner part of the conductor of two or more turns of the conductor located around the first portion of the central axis is spaced from the central axis by at least one first distance. The inner part of the conductor of one or more turns of the conductor located around the second portion of the central axis is spaced from the central axis by at least one second distance greater than the at least one first distance.

In an example, the method comprises locating a spacer in the gap in the core to form a gap around the core. An outer surface of a portion of the spacer is located a distance from the central axis that is greater than a distance from the central axis of an outer surface of the second component that forms the core.

In an example, the method comprises contacting the outer surface of the portion of the spacer with the one or more turns of conductor located around the second portion of the central axis.

In a seventh aspect according to the invention, there is provided a method of forming an inductor coil, comprising:.

According to the invention, the method comprises compressing at least one section of the first part of the length of conductor in the direction of the central axis.

In an eighth aspect according to the invention, there is provided a method of forming an inductor coil, comprising:.

<FIG> relate to inductor coils and methods of forming or manufacturing inductor coils.

According to the invention, an inductor coil comprises a first component <NUM>, a second component <NUM>, and a length of conductor <NUM>. The first component is located adjacent to the second component. A core <NUM> is formed from the first component and the second component. The core is located along a first portion of a central axis and a second portion of the central axis. Along a third portion of the central axis the first component is spaced from the second component to form a gap <NUM>, <NUM> in the core. The third portion of the central axis is between the first portion of the central axis and the second portion of the central axis. A first part of the length of conductor is located around the first portion of the central axis, located around the second portion of the central axis, and located around the third portion of the central axis to form a plurality of turns of conductor around the core and the gap in the core. At least one section of the first part of the length of conductor is compressed in the direction of the central axis.

In an example, a spacer <NUM> is located in the gap in the core to form a gap <NUM> around the core. An outer surface of a portion of the spacer is located a distance from the central axis that is greater than a distance from the central axis of an outer surface of the first component and an outer surface of the second component that form the core.

In an example, a dimension of the portion of the spacer adjacent to the outer surface of the first component and the outer surface of the second component in the direction of the central axis is greater than a dimension of the gap <NUM> in the core in the direction of the central axis.

In an example, the spacer comprises a central hole <NUM> configured to be located around the central axis.

According to the invention, an inductor coil comprises a first component <NUM>, a second component <NUM>, and a length of conductor <NUM>. The first component is located adjacent to the second component. A core <NUM> is formed from the second component. The core is located along a first portion of a central axis. Along a second portion of the central axis the first component is spaced from the second component to form a gap <NUM>, <NUM> in the core. The second portion of the central axis is between the first portion of the central axis and the first component. A first part of the length of conductor is located around the first portion of the central axis, and located around the second portion of the central axis to form a plurality of turns of conductor around the core and the gap in the core. At least one section of the first part of the length of conductor is compressed in the direction of the central axis.

According to the invention, each turn of conductor of the plurality of turns of conductor has an inner part of the conductor spaced at least one distance from the central axis in a direction perpendicular to the central axis. The inner part of the conductor of two or more turns of the conductor located around the first portion of the central axis is/are spaced from the central axis by at least one first distance. The inner part of the conductor of one or more turns of the conductor located around the second portion of the central axis is spaced from the central axis by at least one second distance greater than the at least one first distance.

In an example, a spacer <NUM> is located in the gap in the core to form a gap <NUM> around the core. An outer surface of a portion of the spacer is located a distance from the central axis that is greater than a distance from the central axis of an outer surface of the second component that forms the core.

In an example, a dimension of the portion of the spacer adjacent to the outer surface of the second component in the direction of the central axis is greater than a dimension of the gap <NUM> in the core in the direction of the central axis.

According to the invention, an inductor coil comprises a first component <NUM>, a second component <NUM>, and a length of conductor <NUM>. The first component is located adjacent to the second component. A core <NUM> is formed from the first component and the second component. The core is located along a first portion of a central axis and a second portion of the central axis. Along a third portion of the central axis the first component is spaced from the second component to form a gap <NUM>, <NUM> in the core. The third portion of the central axis is between the first portion of the central axis and the second portion of the central axis. A first part of the length of conductor is located around the first portion of the central axis, located around the second portion of the central axis, and located around the third portion of the central axis to form a plurality of turns of conductor around the core and the gap in the core. Each turn of conductor of the plurality of turns of conductor has an inner part of the conductor spaced at least one distance from the central axis in a direction perpendicular to the central axis. The inner part of the conductor of two or more turns of the conductor located around the first portion of the central axis and/or located around the second portion of the central axis is/are spaced from the central axis by at least one first distance. The inner part of the conductor of one or more turns of the conductor located around the third portion of the central axis is spaced from the central axis by at least one second distance greater than the at least one first distance.

According to the invention, an inductor coil comprises a first component <NUM>, a second component <NUM>, and a length of conductor <NUM>. The first component is located adjacent to the second component. A core <NUM> is formed from the second component. The core is located along a first portion of a central axis. Along a second portion of the central axis the first component is spaced from the second component to form a gap <NUM>, <NUM> in the core. The second portion of the central axis is between the first portion of the central axis and the first component. A first part of the length of conductor is located around the first portion of the central axis, and located around the second portion of the central axis to form a plurality of turns of conductor around the core and the gap in the core. Each turn of conductor of the plurality of turns of conductor has an inner part of the conductor spaced at least one distance from the central axis in a direction perpendicular to the central axis. The inner part of the conductor of two or more turns of the conductor located around the first portion of the central axis is spaced from the central axis by at least one first distance. The inner part of the conductor of one or more turns of the conductor located around the second portion of the central axis is spaced from the central axis by at least one second distance greater than the at least one first distance.

According to the invention, a method of forming an inductor coil comprises:.

It is to be noted, that the method steps can be carried out in different orders and certain steps can be carried out contemporaneously, and certain steps can be carried out more than once - for example the compressing step.

In an example, the method comprises locating a spacer <NUM> in the gap in the core to form a gap <NUM> around the core. An outer surface of a portion of the spacer is located a distance from the central axis that is greater than a distance from the central axis of an outer surface of the first component and an outer surface of the second component that form the core.

According to the invention, a method of forming an inductor coil comprises.

In an example, the method comprises locating a spacer <NUM> in the gap in the core to form a gap <NUM> around the core. An outer surface of a portion of the spacer is located a distance from the central axis that is greater than a distance from the central axis of an outer surface of the second component that forms the core.

It is to be noted, that the method steps can be carried out in different orders and certain steps can be carried out contemporaneously.

Thus, a new technology has been developed that in specific embodiments utilizes a deformable conductor formed for example from multi-stranded wire or Litz wire/coils and methods for gap distribution of the fringing field that provides for copper packing by compressing the conductor wire, including for example after it has been formed around the core area shape, and also avoiding the fringing field to achieve a high performance coil with low thermal heat generation and brilliant thermal transfer.

Specific embodiments are now described, where reference is again made to <FIG>.

<FIG> shows a cross-section through a detailed specific embodiment of an inductor coil. A first component part <NUM> of a ferrite material is shown at the top. This has a base portion, and a cylindrical core portion extending downwards. Outer limb portions extend downwards and are spaced from the core portion and within which turns of a conductor <NUM> in the form of a multi-strand wire can be located. A second component part <NUM> again of a ferrite material shown in the bottom. This again has a base portion, and a cylindrical core portion <NUM> extending upwards, and outer limb portions that extend upwards and spaced from the core portion and within which turns of the conductor <NUM> can be located. The core portions of the of the first component part of the second component part form a core <NUM>. A centre <NUM> in the core is shown between the two component parts, with a centre gap has a dimension <NUM> that can for example be <NUM>, but can be greater than or less than this. Six turns of the multi-strand wire are shown wound around the core and the gap in the core, but there can be less than or more than this. In addition to a gap <NUM> being provided between the cores, a gap <NUM> is formed around this central gap and the wire turns do not encroach into this gap <NUM>, and as shown wire turns have been deformed to keep them out of this gap <NUM>. Thus <FIG> illustrates that the cross section for each turn is kept the same, but under compression free space is created to avoid the gap created by the ferrite. The central gap <NUM> is the area in which non-conductive material spacer <NUM> can be placed that forms the gap <NUM>, discussed in more detail below.

<FIG> shows a cross-section through a detailed specific embodiment of an inductor coil, that is similar to that shown in <FIG> except that the gap is distributed across a combination of limb portions, with the wire turns in the region of the central <NUM> being kept out of an inner <NUM> and also been kept out of an outer gap <NUM>. Thus, in addition to a gap <NUM> in the core <NUM>, there is also a gap <NUM> in the outer limb portions. Both of these gaps can be filled with spaces, that create the inner <NUM> and outer <NUM> gaps.

<FIG> shows a cross-section through the six wire turns of the embodiment of <FIG> and illustrates the wire turns of the coil after compression, showing the shape of the gap <NUM> that is formed that avoids the fringing field of a centre gapped core. This could be the same for an off centre gap or a distributed gap in several locations between the two core components. This shape can be retained further by using such multi-stranded or litz wire with self-bonding characteristics.

<FIG> shows a cross-section through a detailed specific embodiment of an inductor coil. A first component part <NUM> of a ferrite material is shown at the top. This has a base portion. A second component part <NUM> again of a ferrite material shown at the bottom. This again has a base portion, and has a cylindrical core <NUM> extending upwards. Outer limb portions extend upwards and are spaced from the core, within which turns of a conductor <NUM> in the form of a multi-strand wire can be located. The core <NUM> is spaced from the base portion of the first component part to form a gap <NUM> in the core. Six turns of the multi-strand wire or shown wound around the core and the gap in the core, but there can be less than or more than this. In addition to a gap <NUM> being provided between the core and the first component part, a gap <NUM> is formed effectively in the core between the core and the first component part, and the wire turns do not encroach into this gap <NUM>, and as shown wire turns have been deformed to keep them out of this gap <NUM>. Thus again <FIG> illustrates that the cross section for each turn is kept the same, but under compression free space is created to avoid the gap created by the ferrite. The top gap <NUM> is the area in which non-conductive material spacer <NUM> can be placed that forms the gap <NUM>, discussed in more detail below.

<FIG> shows a detailed specific embodiment of an inductor coil, for example as shown in <FIG> that has a central gap <NUM> in the core. The first component part <NUM> and the second component part <NUM> shown separated from one another, and the spacer <NUM> is shown that also has a central hole <NUM>. As shown there was a space <NUM> in both the first and second component parts for windings of the conductor <NUM> in the form of a multi-strand wire. Thus this figure illustrates a non-conductive insert (spacer <NUM>) that extends over the pole length. This can be used with and without the hole in the centre <NUM> of the non-conductive part. This can be added during the compression or after the compression of the wires to ensure that the wires do not enter the fringing field after compression.

<FIG> shows a representative cross-section through an inductor coil, showing the outer limbs of a first component part <NUM> or a second component part <NUM>, showing a top surface of core <NUM> of one of the <NUM> component parts. With a cross-section through the centre of the gap spacer <NUM> the outer limbs of the first or second component part or actually also not actually been cut through but are the top surface. <FIG> shows a representation on the left of how the turns of the wire can be pushed sideways by the spacer <NUM>, and shows a representation on the right of how the turns of the wire can be deformed by the spacer <NUM> in the region of central gap <NUM> to keep the turns of the wire conductor <NUM> out of the fringing field. The figures therefore illustrate how the ring spacer <NUM> can be used to either compress the conductive wire <NUM> or to allow the bundle or strand to jump over the space containing the fringing field, and illustrates of how the wire could form a bump <NUM> outside of the core shape where space <NUM> may be free for the wire to enter. Thus the spacer <NUM> by keeping the terms of the wire conductor out of the fringing field, produces heat production, improves thermal stability.

<FIG> shows a cross-section through a detailed specific embodiment of an inductor coil, for example as shown in <FIG>. This shows that the wire conductor <NUM> in the form of a multi-strand wire can be partially compressed prior to it being located around the core <NUM> formed from the first component part <NUM> and the second component part <NUM>. Here, the wire conductor <NUM> has been wound around a spacer <NUM> with a central hole <NUM>, and that has a cylindrical sleeve <NUM>. The wires have then been compressed, and the end portions of the spacer <NUM> are wider than the diameter of the cylindrical core <NUM>, and therefore form spaces <NUM> around the spacer <NUM> where there is no wire. When the first component part and the second component part are brought together, the core portions slide within the wire turns and the depth of the already compressed wire turns is slightly deeper than their available space and therefore the wire is further compressed due to the mounting force, where for example the outer limbs of the first component part <NUM> and the second component part <NUM> can be brought together as shown in <FIG> but with the core portions not meeting to form the core <NUM> that has a gap <NUM>. The sleeve <NUM> is not necessary and indeed the wires can be deformed to have a space <NUM> that will be located around the gap <NUM> in the core <NUM> without requiring the spacer <NUM>.

<FIG> shows at the top a cross-section through a detailed specific embodiment of an inductor coil, for example as shown in <FIG>, at the bottom representation is shown of terminal connections to both ends of the conductor <NUM> in the form of a multi-strand wire. Thus a ferrite cage is provided, with a gap <NUM> in the core <NUM> provided at the top, where the spacer <NUM> is located to create a gap <NUM> around the gap in the core whether windings of the conductor do not encroach. In this embodiment, it can be easier to mount the spacer <NUM> than for a centrally mounted spacer <NUM>. The spacer <NUM> can in effect be used as a push-up art in order to move the filaments or strands of the wire turns away, and to create the necessary defamation of at least one winding at the top. Thus, in this embodiment the copper windings can be transformed into a different geometry by pusher part which is working like a robust eddy current mitigation element. The view from the top, shows top <NUM> and bottom terminals <NUM> where for example the end of the windings can be prepared to be connected with power electronic boards, such as a PCB. Various mechanisms can be utilised to connect the end of the conductor wire is required, for example with a compressed coil terminal with a whole use for mechanical fixation pressed coil terminal disordered for example to a tin plated brass multi-terminal connector and then soldered to a PCB.

<FIG> shows a cross-section through a detailed specific embodiment of an inductor coil, for example as shown in <FIG>. A spacer part has created a gap <NUM> around a gap <NUM> between the core <NUM> of a second component part <NUM> and the first component part <NUM>. The wire conductor <NUM> is located the core and has been deformed. The wire conductor <NUM> is in the form of a multi-strand wire with bundles of wire 18a-18n. The wire conductor <NUM> was in one embodiment compressed whilst the wound configuration, then placed around the core <NUM> and then further compressed when the first component part <NUM> is connected to the second component part <NUM> and the spacer <NUM> was pushed downwards deforming one or more turns of the conductor as it was pushed downwards, and indeed all of the turns of the conductor <NUM> can be further compressed as the first and second component parts are connected one to the other. <FIG> shows a representation of how a cross-section of the multi-strand wire can deform and maintain its overall cross-section, and therefore current carrying capability, in the new inductor coil, but provide that wire is moved away from the gap in the core providing the benefits as described above.

<FIG> shows a combination of the first part <NUM> and the second part <NUM> which form a magnetic flux cage, which is designed to carry a coil which is made from a length of the conductor <NUM>. The magnetic field <NUM> penetrates the material of the first and the second part at least partially. In the surrounding space around the gap between the first and the second part there is a fringing field <NUM> which reaches into the space which is designed to carry a coil. The coil is not shown in <FIG>. The fringing field <NUM> would create eddy losses as soon as the magnetic fringing field is alternating or changing. The losses increase as the frequency increases. The length of the conductor <NUM> (not shown) preferably comprises a multitude of partially parallel strands or fibers, forming a woven filament wire rope or a twisted wire or a litz wire. The benefit of the use of thin filaments is the reduced eddy current creation, which is smaller in case of thinner filaments. This new solution combines the use of electrically parallel filaments in each turn with the freedom of the space volume of the fringing field <NUM> which is not occupied by wires or filaments.

<FIG> shows an embodiment with two symmetrical parts <NUM> and <NUM> (they need not be symmetrical) which are forming a core <NUM> and a gap <NUM>. <FIG> shows a coil made from a length of conductor <NUM> partially inserted into the first part <NUM> and the second part <NUM> that are still open. The cross-sectional shape of the windings of the length of conductor <NUM> comprise a cross-sectional shape deformation at least in turn <NUM> and <NUM> in the neighbourhood of the fringing field. The deformation is accompanied by a rearrangement of the group of electrically parallel filaments. A deformation of the single fibers may be present as well. The deformation of the fiber bundle, which is related to a turn of the winding of the conductor <NUM>, is designed to create an open free space <NUM> around the gap <NUM> between part <NUM> and part <NUM>. The free space <NUM> may be filled with a spacer, which is made from magnetically inert material in order to prevent wires and or fibers from penetrating or moving into that free space <NUM>. However, the spacer is not essential as the wires and or fibers can be arranged not to penetrate or move into the free space <NUM>, for example by having the wires or fibers bound one to the other, but the spacer provides a mechanism by which it is not possible for the wires or fibers to move into the "free space <NUM>" occupied by the magnetically inert material of the spacer.

<FIG> shows a preformed coil comprising a pre-shaped length of conductor <NUM> prior to mounting this coil into the fee space inside of a magnetic flux cage. The magnetic flux cage comprises a top part <NUM> and a bottom part <NUM>, which comprises a core <NUM> that is short enough to comprise a magnetic flux gap between top part <NUM> and bottom part <NUM>. The top part <NUM> may have a part of a recess to form a precise gap as shown in <FIG>, or may be flat as well. The pre-shaped coil <NUM> comprises a deformation of at least the winding which is closest to the magnetic flux gap and the fringing field there. The conductor <NUM> preferably comprises electrically parallel wires or fibers and may be a litz wire or a stranded wire or a laminated conductor. The pre-shaped conductor <NUM> may be pre-compressed prior to the mounting and may show a relaxation after removal of the pre-compression means. The coil <NUM> may be re-compressed after fixing the top part <NUM> and the bottom part <NUM> in order to create a stable magnetic flux cage of the inductor. The re-compression may result in a compression of the conductor <NUM> in axial direction and a bit of expansion of the coil in the outer radius into radial direction of the coil. A mechanical contact may be existent between the outer surface of the coil <NUM> and the outer parts of the magnetic flux cage <NUM>, <NUM> but a free space <NUM> is left free between the inner surface of the coil <NUM> and the gap area and around the gap area. Between the lower area of the core <NUM> and the inner surface of the coil a mechanical contact may be present. The mechanical contact between the coil and the magnetic flux cage <NUM>, <NUM> may be used in order to conduct thermal energy from the conductor to the magnetic flux cage <NUM>, <NUM>.

In an example the pre-shaped conductor <NUM>, including the pre-shaped free space <NUM>, is manufactured using a winding machine, which is controlling and shaping the cross sectional shape of the conductor <NUM> turn by turn in a design which results in a screw type arrangement of the windings along a central axis <NUM> of the coil. Such arrangements are shown in <FIG> and <FIG>. The windings are pre-compressed in axial direction and bended in a screw-plane around the central axis.

In an example the windings of the coil are pre-shaped into a screw type arrangement around a central axis with a inner open diameter which is designed to fit into the open volume of the magnetic flux ring made from part <NUM> and <NUM>. The screw type winding is then compressed at least partially in axial direction and the winding cross-section is expanded radially according to this compression. The total cross-sectional area of the windings can remain about the same through compression, thus the compression and the change of the cross-sectional shape is associated with a geometrical re-arrangement of the fibers of the thin wires or filaments of the conductor <NUM>, which are forming the compressed part of the conductor.

Thus, a new inductor coil is provided that has a gap in the core, either centrally between to ferrite components or next to one of the ferrite components, with a gap is either an air gap or has a nonconductive spacer. The gap can be important in inductor design, because it can be used with respect to the control of magnetic resistance in magnetic circuit. However, now eddy currents in the windings of the coil are prevented because the wire is kept away from this. Furthermore, copper density of the overall windings of the inductor coil increased due to deformation of the windings through compression, which can occur before and/or during the mounting process. When a nonconductive spacer is utilised, it helps to keep the conductor out of the eddy current space, acts like a pusher will to form a and keeps at least one winding in a deformed geometry, and indeed a counter twist can be provided that creates a partially more parallel (than twisted) multi-strand wire.

Claim 1:
An inductor coil, comprising:
a first component (<NUM>) comprising a first base portion and a first cylindrical core portion;
a second component (<NUM>) comprising a second base portion and a second cylindrical core portion; and
a length of conductor (<NUM>);
wherein, the first cylindrical core portion is located adjacent to the second cylindrical core portion;
wherein, a core (<NUM>) is formed from the first cylindrical core portion and the second cylindrical core portion;
wherein the core is located along a first portion of a central axis and a second portion of the central axis;
wherein, along a third portion of the central axis the first cylindrical core portion is spaced from the second cylindrical core portion to form a gap (<NUM>, <NUM>) in the core, wherein the third portion of the central axis is between the first portion of the central axis and the second portion of the central axis;
wherein, a first part of the length of conductor is located around the first portion of the central axis, located around the second portion of the central axis, and located around the third portion of the central axis to form a plurality of turns of conductor around the core and the gap in the core;
wherein each turn of conductor of the plurality of turns of conductor has an inner part of the conductor spaced at least one distance from the central axis in a direction perpendicular to the central axis, wherein the inner part of the conductor of two or more turns of the conductor located around the first portion of the central axis and/or located around the second portion of the central axis are spaced from the central axis by at least one first distance, and wherein the inner part of the conductor of one or more turns of the conductor located around the third portion of the central axis is spaced from the central axis by at least one second distance greater than the at least one first distance;
and characterized in that at least one section of the first part of the length of conductor between the first base portion and the second base portion is compressed in the direction of the central axis between and by the first base portion and the second base portion.