JP2013157352A - Coil device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil device, appropriate for use as a reactor, which is small-sized, reduces a loss and further improves a DC superposition property.SOLUTION: A reactor 10 comprises a winding core part 20 which is disposed in a columnar shape along an axial direction, flange core parts 30a, 30b in the shape of a flange disposed in both ends in the axial direction of the winding core part 20, respectively, a coil 50 which is disposed in an outer circumference of the winding core part 20, and an insulative cover members 60a, 60b which are disposed between counter surfaces 32a, 32b of the flange core parts 30a, 30b and axial direction end portions 52a, 52b of the coil 50, in which through holes 68a, 68b are formed which the end portions in the axial direction of the winding core part enter, which have an external form as large as or larger than that of the coil 50 and in which axial direction protrusions 64a, 64b are formed in contact with both the counter surfaces 32a, 32b of the flange core parts 30a, 30b and the axial direction end portions 52a, 52b of the coil.

Description

  The present invention relates to a coil device that constitutes a reactor used in, for example, an inverter circuit and an active filter circuit.

  As a coil device for a reactor used in an inverter circuit, an active filter circuit, or the like, an E-shaped core having a coil wound around a central leg and an I-shaped core or a coil wound There have been proposed two cores connected by two external cores.

  Furthermore, a technique for adjusting the inductance characteristics of the reactor by providing a gap in the connecting portion between the cores has also been proposed (see Patent Document 1, Patent Document 2, etc.).

  In the prior art, a reactor in which a gap is provided at the connecting portion between the cores has an effect that the inductance characteristics can be easily adjusted. On the other hand, the leakage magnetic flux from the gap is linked to the current flowing through the coil, resulting in a large loss. The problem has occurred.

JP-A-8-148353 Japanese Unexamined Patent Publication No. 2000-1000063

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a coil device suitable for use as a reactor that is small in size, has low loss, and has excellent direct current superposition characteristics.

In order to achieve the above object, a coil device according to the present invention comprises:
A core core portion arranged in a columnar shape along the axial direction;
A bowl-shaped bowl core part disposed at each of axial ends of the core core part,
A coil disposed on the outer periphery of the core core portion;
A through hole is formed between the facing surface of the flange core portion and the axial end portion of the coil, and each of the axial end portions of the core core portion is formed therein, and is equivalent to the outer shape of the coil. An insulating cover member having the above-described outer shape and formed with an axial convex portion that contacts both the opposing surface of the collar core portion and the axial end portion of the coil.

  In the coil device of the present invention, since the axial convex portion that secures the distance between the facing surface of the heel core portion and the axial end portion of the coil is formed, the cover member is installed on the facing surface of the heel core portion. Only in this manner, the coil can be easily positioned in the axial direction. In addition, the creepage distance between the coil and the core portion can be ensured without reducing the heat dissipation of the core portion.

  In the coil device according to the present invention, the heel core portion and the heel core portion are connected by a single core core portion, and the magnetic field generated by the coil is an open magnetic field that propagates in the air at portions other than the core portion. It becomes a road. Conventionally, in the case of a coil device having an open magnetic circuit with a single core core, even if a gap material is interposed between the saddle core and the core core, the direct current superimposition characteristics of the inductance are improved. It was thought that there was nothing to do.

  However, as a result of research by the present inventors, it has been found that the direct current superposition characteristics of the inductance can be improved by providing a gap or interposing a gap material between the flange core portion and the core core portion. . Therefore, the coil device according to the present invention can be suitably used as a reactor, and can realize a small-sized and low-loss reactor having good DC superposition characteristics.

  Preferably, at least one of the core core part and the flange core part are connected with a predetermined gap. More preferably, an insulating gap material having a predetermined thickness is interposed between at least one of the core core part and the flange core part.

  In the coil device according to the present invention, since the axial convex portion that secures the distance between the opposing surface of the flange core portion and the axial end portion of the coil is formed, the clearance between the gap or the gap material and the coil is ensured. It becomes possible to do. Therefore, it is possible to effectively prevent the leakage magnetic flux from the gap or gap material from interlinking with the current flowing through the coil. Therefore, loss can be reduced and reactor efficiency can be improved.

  The cover member may be attached to the saddle core portion so as to cover the entire surface of the facing surface except for the through hole.

FIG. 1 is a cross-sectional view of a reactor as a coil device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the reactor shown in FIG. 3A is a perspective view of the cover member shown in FIG. FIG. 3B is a perspective view showing a modification of the cover member shown in FIG. 3A. FIG. 4 is a plan view showing a further modification of the cover member shown in FIG. 3A. FIG. 5 is an enlarged cross-sectional view of a main part of the reactor shown in FIG. 6 is a cross-sectional view showing a modification of the reactor shown in FIG. FIG. 7 is a circuit diagram showing an application of the reactor shown in FIG. 8A and 8B are graphs showing the DC superposition characteristics of inductance. FIG. 9 is a graph showing the efficiency of the reactor according to the example of the present invention and the comparative example.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
As shown in FIG. 1 and FIG. 2, a reactor 10 as a coil component according to an embodiment of the present invention has a core core portion 20 arranged in a columnar shape along the axial direction (the direction of the Z axis). . Note that the directions perpendicular to each other including the Z axis are defined as an X axis and a Y axis.

  In this embodiment, the core core part 20 is divided into three core parts 20a to 20c along the axial direction Z, but is not limited to three, and may be divided into two or four or more. It is not necessary to be divided. However, by configuring the core core part 20 to be divided, it is easy to arrange the core core part 20 inside the cylindrical bobbin 40 and to easily provide a gap between the cores. There is.

  At both ends in the axial direction of the core core part 20, bowl-shaped saddle core parts 30 a and 30 b are arranged via gap members 70 a and 70 b forming magnetic gaps. The shape of the gap members 70a and 70b is a circular sheet shape in the present embodiment, but the shape is not particularly limited and may be other shapes. Further, in the present embodiment, the heel core portions 30a and 30b have a quadrangular plate shape, but may have other polygonal shapes, circular plate shapes, or elliptic plate shapes.

  However, the outer diameters of the flange core portions 30a and 30b are larger than the outer diameter of the core core portion 20, and the outer shapes of the flange core portions 30a and 30b with respect to the outer shape of the core core portion 20 are XY axis planes. In, it becomes a protruding shape. In addition, when the collar core portions 30a and 30b are other than the circular plate shape, the outer diameter of the collar core portions 30a and 30b means the diameter of the inscribed circle. The outer diameter of the core core part 20 is also the same.

  In the present embodiment, the gap members 70a and 70b are disposed between the flange core portions 30a and 30b and the core core portion 20, but one of the gap members 70a and 70b is not necessarily provided. .

  A cylindrical bobbin 40 is disposed on the outer periphery of the core core part 20. A coil 50 is wound around the outer periphery of the bobbin 40. The bobbin 40 is formed in a cylindrical shape in accordance with the shape of the core core part 20, but when the core core part 20 is in a polygonal column shape, the shape of the bobbin 40 is also in a polygonal cylindrical shape accordingly. It may be. Moreover, it is preferable that the coil 50 wound around the outer periphery of the bobbin 40 is wound in a coil shape before being arranged on the outer periphery of the bobbin 40. The coil 50 is manufactured by, for example, winding a conductive wire covered with an insulating layer, but is not particularly limited.

  In the present embodiment, insulating cover members 60a and 60b are disposed between the facing surfaces 32a and 32b of the flange core portions 30a and 30b and the axial end portions 52a and 52b of the coil 50. Each of the cover members 60a and 60b has a flat base plate portion 62a and 62b, and through holes 68a and 68b into which the end portions in the axial direction of the core core portion 20 are respectively formed are formed at the center portions thereof. It is.

  In the present embodiment, the base plate portions 62a and 62b are formed in a quadrangular shape in accordance with the shape of the flange core portions 30a and 30b, and side wall portions 66a and 66b are integrally formed on the outer periphery thereof. The base plate portions 62a and 62b and the side wall portions 66a and 66b integrally cover the facing surfaces 32a and 32b of the flange core portions 30a and 30b.

  Further, in the periphery of the through holes 68a and 68b of the base plate portions 62a and 62b, an axial direction is secured to secure a distance between the facing surfaces 32a and 32b of the flange core portions 30a and 30b and the axial end portions 52a and 52b of the coil 50. The convex portions 64a and 64b are integrally formed. The axial convex portions 64a and 64b come into contact with both the opposing surfaces 32a and 32b of the flange core portions 30a and 30b and the axial end portions 52a and 52b of the coil.

  As shown in FIG. 3A, the axial convex portions 64a and 64b have a cylindrical shape in this embodiment, but may have a polygonal cylindrical shape or other shapes as shown in FIG. 3B. . Further, the axial protrusions 64a and 64b are not necessarily formed continuously in the circumferential direction, and may be formed intermittently along the circumferential direction of the through holes 68a and 68b as shown in FIG. good.

  In the present embodiment, the pair of cover members 60a and 60b disposed at both ends in the Z-axis direction of the core core part 20 are configured by cover members having the same shape, but are not necessarily the same, For example, one may be the cover member shown in FIG. 3A and the other may be the cover member shown in FIG. 3B.

  The cover members 60a and 60b are formed of an insulating member such as PBT, phenol resin, nylon resin, PPS, or PC. The core core part 20 and the saddle core parts 30a and 30b are each made of ferrite or a metal magnetic material, and can be made of the same magnetic material. Preferably, the core core part 20 is made of a metal magnetic material. The heel core portions 30a and 30b are made of ferrite.

  That is, since the magnetic flux density tends to be high in the core core portion 20 around which the coil 50 is wound, a metal magnetic material having a high saturation magnetic flux density is used, and in the saddle core portions 30a and 30b where the magnetic flux density is difficult to increase, the core density is low. By using a lossy ferrite material, a small and low-loss reactor can be realized.

  In addition, iron powder, sendust, Fe-Si alloy, permalloy, amorphous, etc. can be used as the metal magnetic material, and high saturation magnetic flux density material, low loss material, etc. can be used as the ferrite. is there.

  The bobbin 40 is made of an insulating member such as PBT, phenol resin, nylon resin, PPS, or PC. The thickness of the bobbin 40 is not particularly limited, but is preferably 1 to 2 mm.

  The gap members 70a and 70b are made of a nonmagnetic material such as PBT, phenol resin, nylon resin, PPS, or PC. The thickness g1 of the gap members 70a and 70b (thickness after mounting as shown in FIG. 5) is not particularly limited, but is determined so as to improve the direct current superposition characteristics, and is preferably 0.1 to 2 mm.

  As shown in FIG. 5, the protrusion height of the axial protrusion 64a (same for 64b) in the cover member 60a (same for 60b) is the axial end of the coil 50 from the surface of the gap member 70a (same for 70b). The distance c1 to 52a (same for 52b) is preferably determined to be 2 to 10 mm, and more preferably 5 to 10 mm. Setting the distance c1 within such a range improves the reactor efficiency and contributes to the miniaturization of the reactor.

  In the present embodiment, the ratio (S1 / S2) between the area S1 of the XY axis cross section of the core core part 20 and the area S2 of the facing surface 32a (same for 32b) of the flange core part 30a (same for 30b). ) Is preferably 2-6. By setting the area ratio in such a range, the reactor efficiency is improved and the reactor is reduced in size.

  In the embodiment described above, as shown in FIG. 1, the base plate portions 62a and 62b of the cover members 60a and 60b integrally cover the facing surfaces 32a and 32b of the flange core portions 30a and 30b. However, the present invention is not limited to this, and as shown in FIG. 6, only a part of the facing surfaces 32a and 32b may be covered.

  However, it is preferable that the outer peripheral portions 63a and 63b of the base plate portions 62a and 62b of the cover members 60a and 60b protrude beyond the outer diameter shape of the coil 50.

  In the reactor 10 of this embodiment, axial convex portions 64a and 64b that secure the distance between the opposing surfaces 32a and 32b of the flange core portions 30a and 30b and the axial end portions 52a and 52b of the coil 50 are formed. Therefore, the axial positioning of the coil 50 can be easily performed only by installing the cover members 60a, 60b on the facing surfaces 32a, 32b of the collar core portions 30a, 30b. Moreover, the creeping distance between the coil 50 and the core portions 30a and 30b can be ensured without reducing the heat dissipation of the core portions 20, 30a and 30b.

  In addition, the reactor 10 according to the present embodiment is configured such that the core core portion 30a and the core core portion 30b are connected by a single core core portion 20, and the magnetic field generated by the coil 20 is not in the portion other than the core portion. It becomes an open magnetic path that propagates in the air. Conventionally, in the case of a single core core portion and an open magnetic path reactor, even if a gap material is interposed between the saddle core portion and the core core portion, the direct current superposition characteristics of the inductance are improved. It was thought that nothing would happen.

  However, due to research by the present inventors, a direct current superposition characteristic of inductance is improved by providing a gap between the saddle core portions 30a, 30b and the core core portion 20 or by interposing the gap members 70a, 70b. It was found to be. Therefore, in this embodiment, a DC superposition characteristic is favorable, and a small and low-loss reactor can be realized.

  In the reactor 10 according to the present embodiment, axial convex portions 64a and 64b that secure the distance between the opposing surfaces 32a and 32b of the flange core portions 30a and 30b and the axial end portions 52a and 52b of the coil 50 are formed. Therefore, it is possible to ensure the distance between the gap members 70a and 70b and the coil 50. Therefore, it is possible to effectively prevent the leakage magnetic flux from the gap material from interlinking with the current flowing through the coil 50. Therefore, loss can be reduced and reactor efficiency can be improved.

  For example, as shown in FIG. 7, the reactor 10 according to the present embodiment is a step-up reactor 10 </ b> A of a power conditioner 100 in solar power generation or a smooth rear reactor 10 according to the present embodiment is a DC-DC converter in solar power generation. It can also be used as a high power transformer.

  The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.

  For example, the reactor 10 may be entirely covered with resin, or may be fixed by a fixing jig. Furthermore, the gap members 70a and 70b and the axial protrusions 64a and 64b may be integrally formed. That is, the gap members 70a and 70b and the cover members 60a and 60b may be integrally formed. The coil device according to the present invention may be used for purposes other than the use of a reactor.

  Further, a gap material may be interposed between the core portions 20a to 20c divided in the axial direction constituting the core core portion 20.

Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples.
Example 1

  A reactor 10 shown in FIGS. 1 to 3A was produced. The thickness of the gap members 70a and 70b made of PBT was 1.5 mm. The results of measuring the DC superposition characteristics of the reactor 10 are shown by the solid lines shown in FIGS. 8 (A) and 8 (B).

  The direct current superposition characteristics of the reactor 10 were measured by measuring the inductance of the reactor 10 while flowing the direct current Idc and examining the change.

The direct current superposition characteristics of the reactor according to Comparative Example 1 manufactured in the same manner except that the gap members 70a and 70b are not provided are indicated by dotted lines shown in FIGS. 8 (A) and 8 (B). Compared to Comparative Example 1, it was confirmed that in Example 1, the change in the inductor was small and the DC superposition characteristics were improved regardless of the magnitude of the current (Idc).
Example 2

  The ratio (S1 / S2) of the area S1 of the XY axis cross section of the winding core part 20 and the area S2 of the facing surface 32a (same for 32b) of the saddle core part 30a (same for 30b) is 1. A reactor 10 was produced in the same manner as in Example 1 except that the ratio was 5 times. The reactor efficiency of the reactor according to Example 2 was measured. The result is shown by the dotted line in FIG. In particular, it was confirmed that the reactor efficiency was improved in a region where the input power was high.

The reactor efficiency was measured with a 2ch Powermeter (Yokogawa WT1800). Reactor efficiency is the ratio of output power to input power.
Example 3

A reactor 10 was produced in the same manner as in Example 2 except that the area ratio (S1 / S2) was twice that of Example 2. The reactor efficiency of the reactor according to Example 3 was measured. The result is shown by the solid line in FIG. In particular, it was confirmed that the reactor efficiency was improved in a region where the input power was high.
Comparative Example 2

  The reactor efficiency was measured about the reactor which concerns on the comparative example 2 which has the core part which connects between the heel core part 30a and the heel core part 30b with two core core parts. A result is shown with the dashed-two dotted line of FIG. In particular, it was confirmed that the reactor efficiency was lowered in a region where the input power was high.

DESCRIPTION OF SYMBOLS 10 ... Reactor 20 ... Core core part 30a, 30b ... Collar core part 32a, 32b ... Opposite surface 40 ... Bobbin 50 ... Coil 52a, 52b ... Axial direction end part 60a, 60b ... Cover member 62a, 62b ... Base board part 64a , 64b ... axial projections 68a, 68b ... through holes 70a, 70b ... gap members

Claims (4)

A core core portion arranged in a columnar shape along the axial direction;
A bowl-shaped bowl core part disposed at each of axial ends of the core core part,
A coil disposed on the outer periphery of the core core portion;
A through-hole is formed between the facing surface of the flange core portion and the axial end portion of the coil, and the axial end portion of the core core portion is inserted thereinto. An insulating cover member having a large outer shape and formed with an axial convex portion that secures a distance between the opposing surface of the flange core portion and the axial end portion of the coil;
A coil device.   The coil device according to claim 1, wherein at least one of the core core part and the flange core part are connected to each other with a predetermined gap.   The coil device according to claim 1 or 2, wherein an insulating gap member having a predetermined thickness is interposed between at least one of the core core part and the flange core part.   The coil device according to claim 1 or 2, wherein the cover member is attached to the heel core portion so as to cover the entire surface of the facing surface except for the through hole.

Images