Coil Component

A coil component includes a core; and a coil wound around the core, in which the core is configured to include plural split cores arranged linearly alongside each other in an axial-center direction of the coil, and an intervening layer made out of a non-magnetic material (for example, comprised of an insulating coating) is disposed between split cores adjacent to each other of the plural split cores.

TECHNICAL FIELD

The present invention relates to coil components.

BACKGROUND ART

There is known a coil component including a rod-shaped core and a coil wound around the core (for example, Japanese Patent Application Laid-open No. 2006-66847).

SUMMARY OF THE INVENTION

According to the present invention, there is provided a coil component including:

a core; and

a coil wound around the core, in which

the core is configured to include a plurality of split cores arranged linearly alongside each other in an axial-center direction of the coil, and

an intervening layer made out of a non-magnetic material is disposed between split cores adjacent to each other of the plurality of split cores.

According to the present invention, it is possible to reduce alternating-current resistance and achieve sufficient quality factors.

DESCRIPTION OF EMBODIMENTS

As a result of studies made by the present inventor, there is a possibility that, with the coil component having the structure as described in Japanese Patent Application Laid-open No. 2006-66847, a large loss of electric power resulting from alternating-current resistance happens, and adequate quality factors cannot be obtained.

The present invention has been made in view of the problem described above, and is to provide a coil component having a structure that can reduce alternating-current resistance and achieve sufficient quality factors.

The above and other objects, advantages and features of this invention will be more apparent from the following description of certain preferred embodiments taken in conjunction with the accompanying drawings.

Hereinbelow, exemplary embodiments according to the present invention will be described with reference to the drawings. Note that, in all the drawings, the same reference characters are attached to similar constituent components, and detailed explanation thereof will not be repeated as appropriate.

First Exemplary Embodiment

First, a coil component40according to this exemplary embodiment will be described with reference toFIGS. 1 to 5.

The coil component40according to this exemplary embodiment includes a core30and a coil10wound around the core30. The core30is configured to include a plurality of split cores31arranged linearly alongside each other in the axial-center direction of the coil10. An intervening layer made out of a non-magnetic material (for example, comprised of an insulating coating35illustrated inFIG. 3) is disposed between split cores31adjacent to each other of the plurality of split cores31.

The “plurality of split cores31forming the core30is arranged linearly alongside each other in the axial-center direction of the coil10” means, in other words, that the coil10is wound along the axial direction of the core30.

With the coil component40according to this exemplary embodiment, the intervening layer made out of a non-magnetic material is disposed between individual split cores31forming the core30to reduce the leakage magnetic flux, and hence, it is possible to reduce alternating-current resistance of the coil10.

The coil component40according to this exemplary embodiment can be favorably used as a resonance coil for a field coupling non-contact power supply system, can be used at high frequencies (for example, a band of MHz) and with large electric power (the order of kw or higher), and has a structure that achieves a low loss. In such a resonance coil, the alternating-current resistance due to stray capacity, proximity effect and core loss causes a large loss. However, in the case of this exemplary embodiment, the leakage magnetic flux can be reduced and the skin effect of magnetic flux can be reduced, so that the core loss can be reduced. Thus, it is possible to achieve a resonance coil exhibiting excellent quality factors.

Below, detailed description will be given.

As illustrated in any ofFIGS. 1 to 3, in the case of this exemplary embodiment, the split cores31forming the core30are each formed into an annular shape (for example, a circular ring shape).

In addition, the coil10is disposed around the core30in a manner such that the axial directions of the split cores31align with the axial-center direction of the coil10(seeFIGS. 5 and 7).

The core30, which is an assembly of circular ring-shaped split cores31, is formed into a hollow cylindrical shape.

That is, in the case of this exemplary embodiment, the core30is comprised of a tubular core body30a, and has a cylindrical hollow portion30bformed inside of the core body30a.

As illustrated inFIG. 3, a coating (for example, an insulating coating35) made out of a non-magnetic material is formed on the entire surface of each of the split cores31. A portion of this coating that faces an adjacent split core31forms the above-described intervening layer.

That is, each of the split cores31is configured to include a split core body34made out of a magnetic material and formed into an annular shape (for example, a circular ring shape), and the insulating coating35formed on the entire surface of the split core body34.

The insulating coating35is made out of an insulating material such as a resin.

Furthermore, for example, in each of the split cores31(each of the split core bodies34), peripheral edge portions on both end surfaces of a split core31in the axial direction thereof (a peripheral edge portion on the outer peripheral side and a peripheral edge portion on the inner peripheral side) are formed into a chamfering shape. Thus, the outer peripheral surface of the core body30a(the side circumferential surface of the core body30a) is constricted at regular intervals in the axial direction of the core30. On the other hand, the inner peripheral surface of the core body30ais expanded toward the outer side in the radial direction at regular intervals in the axial direction of the core30.

However, the present invention is not limited to this example. The outer peripheral surface and the inner peripheral surface of the core body30amay have a cylindrical shape having the same diameter throughout the entire axial direction of the core30(shape without constricted or expanded portion).

As illustrated inFIG. 4, the bobbin20is comprised of a hollow cylindrical bobbin body20a. A cylindrical hollow portion20bis formed inside of the bobbin body20a.

In the bobbin body20a, for example, one or a plurality of openings20cpenetrating the inside and the outside of the bobbin main body20aare formed. That is, the hollow portion20b, which is the inside space of the bobbing body20a, and the external space of the bobbin body20aare communicated with each other through each of the opening20c.

The bobbin20is made out of a resin or other insulating, non-magnetic material.

As illustrated inFIG. 5, the coil10is formed by spirally winding a metal wire10a. The coil10has an outwardly extending piece13at both ends thereof.

The example illustrated inFIG. 5gives an example in which the wire10ais a rectangular wire and the coil10is an edgewise coil. However, the wire10amay be other wire. In addition, the coil10may have a structure other than the edgewise coil.

The outer diameter of the core30(the outer diameter of the core body30a) is smaller than the inner diameter of the bobbin20(the inner diameter of the bobbin body20a).

The inner diameter of the coil10is larger than the outer diameter of the bobbin20(the outer diameter of the bobbin body20a).

As illustrated inFIG. 5, the coil component40is configured by disposing the coil10around the bobbin body20a, and inserting the core30into the hollow portion20bof the bobbin20.

FIGS. 6 and 7are diagrams each illustrating a coil component unit100formed by making plural (for example, two) coil components40into a unit.FIG. 6is a perspective view of the unit, andFIG. 7is a sectional plan view of the unit. The coil component according to the present invention includes the coil component unit100.

As for the positional relationship of the coil component unit100in each ofFIGS. 6 and 7, the directions of forward, backward, left, and right are shown in each drawing. These directions are used only to illustrate the structure of the coil component unit100, and do not necessarily correspond to the positional relationships of the coil component unit100during manufacturing or when in use.

Although any flange portion25(seeFIGS. 6 and 7) of the bobbin20is not illustrated inFIGS. 4 and 5, the bobbin20includes a pair of flange portions25each provided on both ends of the bobbin body20ain the axial direction of the bobbin body20a. These flange portions25are each formed into, for example, a square shape or other rectangular shapes.

In addition, as illustrated inFIGS. 5 and 7, in the axial direction of the bobbin body20a, the longitudinal dimension of the core30is longer than that of the bobbin20, and the end portion of the core30protrudes from each of both ends of the bobbin20.

Here, the two coil components40of the coil component unit100are arranged in parallel so that the axial directions of bobbin bodies20aof these coil components40extend in parallel to each other.

In addition, a flat plate-like partitioning plate80is disposed between the two coil components40.

In the axial direction of the bobbin body20a, both ends of the partitioning plate80are each provided with a cutout-shaped portion80ahaving a shape obtained by cutting out a rectangular-shaped portion from the partitioning plate80.

As illustrated inFIG. 7, a flat plate-like spacer50is disposed at both ends of the coil component40in the axial direction of the bobbin body20a.

In addition, a holding member60is disposed at positions located outside of the spacer50in the axial direction of the bobbin body20a(at a position located in front of the forward-side spacer50inFIG. 7and at a position located behind the backward-side spacer50inFIG. 7).

That is, the coil component unit100includes a pair of spacers50and a pair of holding members60.

Each of the holding members60and the spacers50is used to fix both of the two coil components40that the coil component unit100includes.

The spacers50and the holding members60each have an insertion hole50aand an insertion hole60a, respectively, formed therein. A bolt71is inserted into the insertion hole50aand the insertion hole60aof each of the spacer50and the holding member60, respectively, located at both ends of the coil component40and is also inserted into the hollow portion30bof the core30. A nut72is tightened at the tip end side of the bolt71. With this configuration, a pair of holding members60, a pair of spacers50, and the coil components40are fixed to each other with a fastening member70including the bolt71and the nut72.

That is, by fastening the bolt71and the nut72together, both ends of the core30are sandwiched by the pair of holding members60via the spacers50, respectively.

This configuration creates a state where the plurality of split cores31forming the core30are in pressure contact with each other, reducing positional shift of the plurality of split cores31.

As described above, the coil component unit100(coil component) includes the holding member60that makes the plurality of split cores31in pressure contact with each other by sandwiching both ends of the core30.

The spacer50on one side and a holding member60adjacent to this spacer50are disposed so as to penetrate through a plate surface of the partitioning plate80through the cutout-shaped portion80aon one side (penetrate in the right and left direction inFIGS. 6 and 7).

Similarly, the spacer50on the other side and a holding member60adjacent to this spacer50are disposed so as to penetrate through a plate surface of the partitioning plate80through the cutout-shaped portion80aon the other side (penetrate in the right and left direction inFIGS. 6 and 7).

In addition, the outwardly extending pieces13located at both ends of the coil10of each of the coil components40are provided with a terminal portion15for external connection.

According to the first exemplary embodiment as described above, the intervening layer made out of a non-magnetic material is disposed between the plurality of split cores31forming the core30, and hence, it is possible to reduce alternating-current resistance of the coil10.

That is, since the core30includes plural separating magnetic gaps (magnetic gaps existing between split cores31), the leakage magnetic flux from the core30reduces, which makes it possible to reduce the alternating-current resistance of the coil10in a high frequency band.

In the case of this exemplary embodiment, each of the split cores31has an annular shape, and the core30has a hollow cylindrical shape. Thus, the high-frequency magnetic flux not only passes through the outer peripheral surface of the core30but also passes through the inner peripheral surface, which reduces an influence of the skin effect, and hence, it is possible to further reduce the alternating-current resistance.

Second Exemplary Embodiment

Next, the second exemplary embodiment will be described with reference toFIGS. 8 and 9.

The coil component according to this exemplary embodiment differs from the coil component40according to the first exemplary embodiment in that the split cores31forming the core30each have a disk shape, and in other points, is configured in a manner similar to the coil component40according to the first exemplary embodiment.

That is, as illustrated inFIG. 9, the split core31includes a split core body34made out of a magnetic material and formed into a disk shape, and an insulating coating35formed on the entire surface of the split core body34.

For example, in each of the split cores31(each of the split core bodies34), peripheral edge portions on both end surfaces of a split core31in the axial direction thereof are formed into a chamfering shape. Thus, the outer peripheral surface of the core body30a(the side circumferential surface of the core body30a) is constricted at regular intervals in the axial direction of the core30.

However, the present invention is not limited to this example. The outer peripheral surface of the core body30amay have a cylindrical column shape having the same diameter throughout the entire axial direction of the core30(shape without constricted portions).

The coil component unit according to this exemplary embodiment differs from the coil component unit100according to the first exemplary embodiment in that the split cores31forming the core30each have a disk shape. In addition, the coil component unit according to this exemplary embodiment does not include the fastening member70. Instead, the coil component unit according to this exemplary embodiment includes a clamp member (not illustrated) disposed around the coil component. With this clamp member, both ends of the core30are compressed in the axial direction thereof.

In other points, the coil component unit according to this exemplary embodiment is configured in a manner similar to the coil component unit100according to the first exemplary embodiment.

Modification Example

FIG. 10Aillustrates a modification example that corresponds to the structure of the first exemplary embodiment described above.FIG. 10Billustrates a modification example that corresponds to the structure of the second exemplary embodiment described above.

As illustrated inFIGS. 10A and 10B, in the case of this modification example, split cores31adjacent to each other are made adhere to each other through an adhesive layer36made out of a non-magnetic material.

With this configuration, the entire core30can keep its unity without both ends of the core30being sandwiched.

The adhesive layer36is made out of, for example, resin or other insulating, non-magnetic material.

In this modification example, the adhesive layer36constitutes the above-described intervening layer.

These are descriptions of exemplary embodiments with reference to the drawing. However, these are merely examples of the present invention, and various configurations other than those described above may be employed. In addition, the exemplary embodiments described above can be combined as appropriate without departing from the main point of the present invention.

This exemplary embodiment includes the following technical ideas.

(1) A coil component including:

a core; and

a coil wound around the core, in which

the core is configured to include a plurality of split cores arranged linearly alongside each other in an axial-center direction of the coil, and

an intervening layer made out of a non-magnetic material is disposed between split cores adjacent to each other of the plurality of split cores.

(2) The coil component according to (1), in which

the split cores are each formed into an annular shape, and

an axial direction of each of the split cores aligns with the axial-center direction of the coil.

(3) The coil component according to (1) or (2), in which

a coating made out of a non-magnetic material is formed on the entire surface of each of the split cores, and

a portion of the coating that faces an adjacent split core forms the intervening layer.

(4) The coil component according to any one of (1) to (3), further including

a holding member that makes the plural split cores in pressure contact with each other by sandwiching both ends of the core.

This application is based on Japanese Patent Application No. 2017-017076, filed on Feb. 1, 2017, the entire content of which is incorporated hereinto by reference.