JP2015191951A - coil unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the manufacturing cost, while suppressing the load applied to a conductive wire forming a coil.SOLUTION: Coil units (10, 20) are used for noncontact power transmission. The coil unit is formed while containing a magnetic material, and includes a core (11) extending in one direction, protection parts (12, 12a, 21, 21a) covering at least a part of the corner area, and having a curved surface that is convex in a direction away from the core, and a coil (13) formed by a conductive wire wound around the core and the protection parts, so as to extend in other direction intersecting the one direction. In particular, the conductive wire is disposed above the protection part along the curved surface thereof.

Description

  The present invention relates to a technical field of a coil used for an apparatus capable of performing non-contact power transmission, for example.

  As this type of coil, for example, a so-called single-sided coil in which a disk-shaped coil is arranged on one side of a disk-shaped magnetic core has been proposed (see Patent Document 1). Alternatively, a so-called double-sided coil in which a conductive wire is wound around a rectangular magnetic core has been proposed (see Patent Document 2).

  When this type of coil is used for non-contact power transmission, a coil on the power transmission side and a coil on the power reception side are arranged to face each other with a predetermined gap. From the viewpoint of power transmission efficiency, it is desirable that the coil on the power transmission side and the coil on the power reception side are arranged so as to coincide with each other when viewed from above the coil. However, in practice, it is necessary to allow a certain amount of misalignment.

  Here, the allowable range of the positional deviation in the horizontal direction is determined by the shape of the magnetic field generated around the coil. And if it is comparable size, what is called a double-sided coil has a larger tolerance | permissible_range with respect to a position shift than what is called a single-sided coil with a center magnetic field.

  On the other hand, a so-called double-sided coil has a technical problem in that a conductive wire is wound around the magnetic core, so that a relatively large burden is applied to the portion of the conductive wire that contacts the corner of the magnetic core. .

  For this technical problem, for example, a so-called double-sided coil having a magnetic core having a flat or elliptical cross section has been proposed (see Patent Document 3 [FIG. 23] and [FIG. 24]).

JP 2008-87733 A JP 2011-50127 A JP 2013-106477 A

  However, the technique described in Patent Document 3 has a technical problem that, for example, the manufacturing and processing costs of the magnetic core are relatively high.

  This invention is made | formed in view of the said problem, for example, and makes it a subject to provide the coil unit which can suppress the manufacturing cost while suppressing the load concerning the electrically conductive wire which forms a coil.

  In order to solve the above-described problem, the coil unit of the present invention is a coil unit used for non-contact power transmission, and includes a magnetic part and a core having a corner region extending along one direction. And a protection part that covers at least a part of the corner region and has a curved surface that is convex in a direction away from the core, and the core and the protection part so as to extend along another direction that intersects the one direction. And a coil formed of a conductive wire wound around the periphery of the coil, and the conductive wire is disposed along the curved surface on the protection portion.

  The effect | action and other gain of this invention are clarified from the form for implementing demonstrated below.

It is a top view of the coil unit which concerns on 1st Example. It is an expanded sectional view which expands and shows a part of AA 'line cross section in FIG. It is a perspective view of the magnetic body core which concerns on 1st Example. It is a perspective view of the core case which concerns on the modification of 1st Example. It is a top view of the coil unit which concerns on 2nd Example. It is an expanded sectional view which expands and shows a part of BB 'line cross section in FIG. It is a conceptual diagram which shows the relationship between the magnetic body core which concerns on 2nd Example, and a core guide. It is a perspective view of the core guide which concerns on the modification of 2nd Example.

  An embodiment according to the coil unit of the present invention will be described.

  The coil unit according to the embodiment is a coil unit used for non-contact power transmission. The coil unit includes a core, a protection unit, and a coil.

  The core is formed including a magnetic material such as ferrite. A corner region extending along one direction is formed at the end of the core. Note that “along one direction” is not limited to the meaning of being parallel to one direction, and is within a range that can be regarded as a solid line along the one direction. It is a concept that includes directions. “Following other directions” described later is the same concept.

  The protection part covers at least a part of the corner area of the core, and has a convex curved surface in a direction away from the core.

  The coil is formed of a conductive wire wound around the core and the protection portion so as to extend along another direction intersecting with one direction. That is, the conductive wire constituting the coil is wound so as to intersect the corner region of the core. Here, in particular, the conductive wire is disposed along the curved surface of the protective part on the protective part.

  According to the inventor's research, the following matters have been found. That is, for example, when non-contact power transmission is applied to charge a battery mounted on a vehicle such as an electric vehicle, it is considered difficult to accurately align the coil unit on the power receiving side mounted on the vehicle. Therefore, it is desirable that the allowable range for the positional deviation of the coil unit is large. In addition, for example, from the viewpoint of fuel consumption, comfort, and the like, the coil unit on the power receiving side is required to be thin and light.

  As described above, a so-called double-sided coil is excellent with respect to an allowable range for positional deviation. In order to reduce the thickness of the coil unit, it is also necessary to reduce the thickness of the core. In a so-called double-sided coil, since the conductive wire is wound around the core, the curvature of the conductive wire at the end of the core increases as the core thickness decreases.

  Here, the coil unit used for non-contact charging of the battery mounted on the vehicle is used outdoors, and a relatively large current flows through the coil unit. For this reason, there are restrictions on the thickness of the conductive wire forming the coil and the covering material covering the conductive wire. In particular, a relatively soft material is often used for the covering material. Therefore, when the curvature of the conductive wire increases, the load on the conductive wire increases. In addition, it is easy for force to concentrate on the contact between the corner area of the core and the conductive wire, and when the shock is applied to the coil unit from the outside, the conductive wire may be damaged and a failure may occur in the coil unit. .

  A relatively high frequency current flows through the coil unit used for charging the battery mounted on the vehicle. For this reason, as the magnetic material used for the core, ferrite with relatively low loss and relatively low cost is often used.

  In order to eliminate the contact between the corner region of the core and the conductive wire, it is possible to make the end portion of the core into a curved surface by processing such as polishing, but the processing cost becomes relatively high. In particular, since ferrite is a ceramic material and is relatively brittle, for example, a core is often formed by combining a plurality of tile-shaped blocks of, for example, several centimeters square. Then, for example, different molding dies must be used for the block corresponding to the end portion of the core and the block corresponding to the central portion of the core. In addition, in order to improve the dimensional accuracy, the sintered block is polished, but the block corresponding to the end portion of the core and the block corresponding to the central portion of the core, for example, set the polishing apparatus. May need to be changed.

  Therefore, the coil unit according to the present embodiment includes a protection unit that covers at least a part of the corner region of the core. And the protection part has a convex curved surface in the direction away from a core. For this reason, it is not necessary to process the edge part of a core into a curved surface, and a core can be manufactured by a conventional method. Since the protection part is typically formed of a resin material, the molding process is relatively easy, and an increase in manufacturing cost can be suppressed.

  In addition, since the conductive wire forming the coil is disposed along the curved surface of the protective portion, it is possible to prevent force from being concentrated on the contact point between the corner region of the core and the conductive wire. If the curvature of the curved surface of the protective part is changed according to the characteristics of the conductive wire, the load on the conductive wire can be reduced.

  As a result, according to the coil unit according to the present embodiment, the load applied to the conductive wire forming the coil can be suppressed. In addition, the manufacturing cost of the coil unit can be suppressed. Further, since the coil unit is a so-called double-sided coil, the allowable range for positional deviation is relatively large, and is suitable as a coil unit used for non-contact charging of a battery mounted on a vehicle, for example.

  In one aspect of the coil unit according to the embodiment, ribs extending along other directions are formed on the surface of the protection unit.

  According to this aspect, when the conductive wire is wound around the core and the protective portion, the conductive wire can be arranged at equal intervals. In particular, in a relatively large coil unit used, for example, for non-contact charging of a battery mounted on a vehicle, the conductive wire is often wound manually, so that the conductive wire is arranged at equal intervals by a rib. If installed, it will lead to an improvement in quality, which is very advantageous in practice.

  Furthermore, when the conductive wire is wound on the conductive wire already wound around the core and the protective portion, the lower conductive wire is prevented from being displaced by the rib. It can be arranged and is very advantageous in practice.

  In another aspect of the coil unit according to the embodiment, the protection unit covers only the corner region.

  According to this aspect, when the coil unit is operated, the heat of the core due to heat loss is easily dissipated, which is very advantageous in practice. In addition, since the core can be visually observed, for example, cracks and cracks in the core can be found relatively easily at the time of manufacture.

  Alternatively, in another aspect of the coil unit according to the embodiment, the protection unit covers the entire core.

  According to this aspect, the core can be reinforced by the protective portion, which is very advantageous in practice. Further, if the protective portion is formed of, for example, a heat conductive insulating resin, the heat of the core can be appropriately dissipated during the operation of the coil unit, which is very advantageous in practice.

  In another aspect of the coil unit according to the embodiment, the core has a flat plate shape.

  According to this aspect, the coil unit can be reduced in thickness and weight relatively easily, which is very advantageous in practice.

  Embodiments of the coil unit of the present invention will be described with reference to the drawings. In the following drawings, the scales are different for each member in order to make each member recognizable on the drawing.

<First embodiment>
A first embodiment of the coil unit of the present invention will be described with reference to FIGS. FIG. 1 is a plan view of the coil unit according to the first embodiment. FIG. 2 is an enlarged cross-sectional view showing a part of a cross section taken along the line AA ′ in FIG. FIG. 3 is a perspective view of the magnetic core according to the first embodiment.

  In FIG. 1 and FIG. 2, the coil unit 10 includes a magnetic core 11, a core case (bobbin) 12 that covers the magnetic core 11 from the periphery thereof, and a conductive wire wound around the core case 12. And a formed coil 13. The “core case 12” according to the present embodiment is an example of the “protection unit” according to the present invention.

  The magnetic core 11 is typically formed including ferrite. Therefore, as shown in FIG. 3, the magnetic core 11 is formed by bonding a plurality of ferrite blocks to each other with an adhesive, for example, or, for example, a plurality of ferrite blocks are arranged on an insulating thin film sheet. Is formed. The magnetic core 11 is not limited to ferrite and may be formed of various magnetic materials.

  The core case 12 is made of an insulating resin material. As the insulating resin material, it is desirable to use a heat conductive insulating resin material from the viewpoint of dissipating heat generated in the magnetic core 11 during the operation of the coil unit 10. In particular, the core case 12 has a curved surface that is convex in a direction away from the magnetic core 11 (see FIG. 2). Further, in order to fix the magnetic core 11 in the core case 12, for example, an insulating adhesive or silicon may be used.

  The conductive wire forming the coil 13 is typically covered with a coating or covering material, but may not be covered.

  Here, if the core case 12 is not provided, a corner region (see FIG. 3) extending in the Y direction (corresponding to “one direction” according to the present invention) of the magnetic core 11 and the coil 13 are formed. A conductive wire (see FIG. 1) wound so as to extend in a direction (corresponding to “another direction” according to the present invention) comes into contact. Then, for example, when an impact is applied from the outside, the force tends to be concentrated and applied to the portion in contact with the corner region of the conductive wire. For this reason, a conductive wire may be damaged and a malfunction may occur in the coil unit 10.

  Further, when the coil unit 10 is reduced in thickness and weight, the thickness of the magnetic core 11 is reduced, so that the curvature of the conductive wire is increased in the vicinity of the end of the magnetic core 11. Therefore, as the thickness of the magnetic core 11 decreases, the load applied to the conductive wire increases.

  However, in this embodiment, the core case 12 prevents contact between the corner region of the magnetic core 11 and the conductive wire. In addition, since the core case 12 has a curved surface, an increase in the curvature of the conductive wire in the vicinity of the end of the magnetic core 11 is suppressed, the load applied to the conductive wire is reduced, and it is relatively easy. Thinning of the magnetic core 11 can be realized.

  In FIG. 2, for example, the conductive wire forming the coil 13 is wound only in one stage, but may be wound in two or more stages.

(Modification)
Next, a modification of the coil unit 10 according to the first embodiment will be described with reference to FIG. FIG. 4 is a perspective view of a core case according to a modification of the first embodiment.

  In this modification, a plurality of ribs 121 are formed in the vicinity of the end where the curved surface of the core case 12a is formed.

  If comprised in this way, when forming the coil 13, a conductive wire can be arrange | positioned at equal intervals. In addition, when the conductive wire is wound in two or more steps, the rib 121 prevents the lower conductive wire from being displaced, which is very advantageous in practice.

  In particular, in a relatively large coil unit such as used in a battery non-contact charging system mounted on a vehicle, a conductive wire is often wound manually. For this reason, if the conductive wires are arranged at equal intervals by providing the ribs 121, the quality of the coil unit 10 can be improved.

  The height and width of the rib 121 may be set as appropriate according to the specifications of the coil unit 10.

<Second embodiment>
A second embodiment according to the coil unit of the present invention will be described with reference to FIGS. The second embodiment is the same as the first embodiment described above except that a core guide is provided instead of the core case. Therefore, in the second embodiment, the description overlapping with that of the first embodiment is omitted, and the common portions in the drawings are denoted by the same reference numerals, and only the points different from those in FIGS. The description will be given with reference.

  FIG. 5 is a plan view of the coil unit according to the second embodiment. FIG. 6 is an enlarged cross-sectional view showing a part of the cross section taken along line BB ′ in FIG. FIG. 7 is a conceptual diagram showing the relationship between the magnetic core and the core guide according to the second embodiment.

  5 and 6, the coil unit 20 is wound around the magnetic core 11, a core guide 21 that covers a corner region extending in the Y direction of the magnetic core 11, and the magnetic core 11 and the core guide 21. And a coil 13 formed of a turned conductive wire. The “core guide 21” according to the present embodiment is another example of the “protection unit” according to the present invention.

  The core guide 21 is a rod-shaped member having a U-shaped cross-sectional shape (see FIG. 7). The magnetic core 11 may be simply fitted in the groove portion of the core guide 21 or may be fixed by, for example, an adhesive or silicon. In particular, the core guide 21 has a curved surface that is convex in a direction away from the magnetic core 11 (see FIG. 6).

  The core guide 21 is formed of an insulating resin material. Here, the insulating resin material is often opaque. Therefore, by using the core guide 21 that covers only the corner area of the magnetic core 11, for example, in the assembly process of the coil unit 20, the magnetic core 11 can be visually observed, and the operator can see the magnetic core 11. Cracks, cracks, etc. can be found relatively easily, which is very advantageous in practice.

  In addition, the core guide 21 is smaller and lighter than the core case 12 described above. Therefore, by using the core guide 21, the coil unit 20 can be reduced in weight relatively easily and the material cost can be suppressed.

  Note that the core guide 21 may be configured to cover only a portion of the corner region extending in the Y direction of the magnetic core 11 where the conductive wire forming the coil 13 is disposed.

(Modification)
Next, a modification of the coil unit 20 according to the second embodiment will be described with reference to FIG. FIG. 8 is a perspective view of a core guide according to a modification of the second embodiment.

  In this modification, a plurality of ribs 211 are formed in the vicinity of the end where the curved surface of the core guide 21a is formed.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. Coil units with such changes are also included. Moreover, it is included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 10, 20 ... Coil unit, 11 ... Magnetic body core, 12, 12a ... Core case, 13 ... Coil, 21, 21a ... Core guide, 121, 211 ... Rib

Claims (5)

A coil unit used for non-contact power transmission,
A core formed of a magnetic material and having a corner region extending along one direction;
A protective portion that covers at least a part of the corner region and has a curved surface that is convex in a direction away from the core;
A coil formed by a conductive wire wound around the core and the protection portion so as to extend along another direction intersecting the one direction;
With
On the protection part, the conductive wire is disposed along the curved surface.   The coil unit according to claim 1, wherein a rib extending along the other direction is formed on a surface of the protection part.   The coil unit according to claim 1, wherein the protection unit covers only the corner region.   The coil unit according to claim 1 or 2, wherein the protection unit covers the entire core.   The coil unit according to any one of claims 1 to 4, wherein the core has a flat plate shape.