JP2007214453A - Wire-wound electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact wire-wound electronic component having ample inductance with less disorder of windings, and moreover with small DC resistance. <P>SOLUTION: A wire-wound electronic component 2 includes a core 4, having a pair of flanges 4b, 4c at axial direction both ends of winding core 4a, and a wire 10a wound around the wiring core portion 4a. The cross section of the wire 10a is a polygon. When a standard wire diameter of the wire 10a is D, a standard outside diameter in an axial direction center of the wiring core 4a is Φc, and a standard outside diameter in the axial direction both ends of the wiring core 4a is Φe; relation 0<Φc-Φe≤2×D is established. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wire-wound electronic component, and more particularly, to a wire-wound electronic component with a small winding disturbance, a low DC resistance, a small size and sufficient inductance.

  Conventionally, for example, a wound-type electronic component disclosed in Patent Document 1 below is known. In conventional wire-wound electronic components, the cross-section of the wire used for winding is circular, and turbulence is likely to occur between adjacent wires wound around the core, increasing DC resistance. Or the inductance value is reduced.

  Further, in the conventional wound electronic component, it was necessary to form a cement layer in addition to the insulating coating layer on the outer periphery of the wire in order to prevent the wire from being disturbed. By forming the cement layer, adjacent wires wound around the core portion are bonded to each other by the cement layer, thereby preventing winding disturbance.

  However, by forming a cement layer on the outer periphery of the wire in this way, there is a problem that the cross-sectional area of the conductor portion of the wire decreases, the DC resistance increases, and the electromagnetic characteristics such as the inductance value deteriorate. It was. It also goes against the demand for smaller parts.

  As shown in Patent Document 2 below, a wound-type electronic component is known in which the cross-sectional shape of a wire to be wound is a square to prevent winding disturbance. However, in the wound electronic component described in Patent Document 2, the cross-sectional shape of the wire is simply a square.

According to the experiments by the present inventors, it is not possible to prevent the winding wire from being disturbed simply by making the cross-sectional shape of the wire square, and the DC resistance is small and small and sufficient. It has been found difficult to obtain a wound electronic component having inductance.
Japanese Patent Laid-Open No. 7-272937 JP 2005-175180 A

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a wound-type electronic component that is small in winding winding, has low DC resistance, is small, and has sufficient inductance.

In order to achieve the above object, a wire wound electronic component according to the present invention includes:
A core portion having a pair of flanges at both axial ends of the core portion;
A wire wound around the core portion;
A wire-wound electronic component having
The cross section of the wire is polygonal;
When the reference wire diameter of the wire is D, the reference outer diameter at the axial center of the core is Φc, and the reference outer diameter at both axial ends of the core is Φe,
0 <Φc−Φe ≦ 2 × D,
Preferably, the relationship is 0.5 × D ≦ Φc−Φe ≦ 1.5 × D.

  In the wire wound electronic component according to the present invention, not only the cross section of the wire is polygonal, but also the reference wire diameter D of the wire, the reference outer diameter Φc in the axial central portion of the core portion, and the core portion By making the reference outer diameter Φe at both ends in the axial direction have the above relationship, the winding wire can be effectively prevented from being disturbed.

  When (Φc−Φe) is too small, the effect of preventing the wire from being distorted is small, and when (Φc−Φe) is too large, the wire slips at the core portion, and conversely causes turbulence. That is not preferable.

  In the wound electronic component according to the present invention, the reference outer diameter Φc at the axial center portion of the core portion is relatively larger than the reference outer diameter Φe at both axial ends of the core portion. For this reason, the wire having a polygonal cross-section wound around the winding core portion is wound tightly in a state where the wires are moved toward both ends in the axial direction of the winding core portion so that the wires are not separated. Turned. For this reason, the winding disturbance of the wire is effectively prevented. Therefore, characteristics such as an inductance value and a magnetic flux density in the wire winding part in the wound electronic component are improved.

  In the wound electronic component of the present invention, since the inductance value can be improved, the number of windings for obtaining the same inductance value can be reduced. If the number of windings can be reduced, the total length of the wire can be shortened, the DC resistance can be reduced, and the parts can be miniaturized.

  Moreover, in the wire-wound electronic component according to the present invention, since the cross section of the wire is polygonal, when the reference outer diameter is the same (same winding thickness) as compared to a wire having a circular cross section, the wire in the wire The cross-sectional area of the part increases. Therefore, also in this respect, the DC resistance of the wire wound electronic component can be reduced.

  Moreover, in this invention, since the cross section of a wire is made into a polygonal shape, and (Φc−Φe) is set within a predetermined range, a cement layer is formed on the outer periphery of the wires so that adjacent wires come into close contact with each other. There is no need. Therefore, also in this respect, when the same reference outer diameter (same winding thickness) is used, the cross-sectional area of the conductor portion of the wire is increased, and the DC resistance of the wound electronic component can be reduced.

  Furthermore, since adjacent wires are in close contact with each other, even when winding a wire in two or more layers, winding disturbance such as a wire located in the upper layer falling between wires located in the lower layer is also possible. Can be prevented.

  Preferably, the wire has a square cross section. Alternatively, the cross section of the wire is rectangular. By making the cross-section of the wire especially square or rectangular, the adjacent wires on the top, bottom, left and right after winding are in surface contact with each other, the adhesion between adjacent wires is further improved, and the wire winding is more effective. Can be prevented.

  Preferably, an insulating coating layer is formed on the outer periphery of the wire. The cement layer may not be formed on the outer periphery of the insulating coating layer. In the present invention, it is possible to prevent turbulence of the wire without forming a cement layer on the outer periphery of the wire.

  Preferably, the reference outer diameter of the core portion gradually changes from the axial center portion of the core portion toward both axial ends of the core portion. For example, it is preferable that the outer circumferential axial cross-section of the winding core is an arc shape with a predetermined radius.

  In this way, the wire has a shape in which the reference outer diameter of the core portion gradually changes from the axial center portion of the core portion toward both end portions in the axial direction. The effect of being closely wound in a state where the wires are not separated from each other is increased.

  In addition, in this invention, a polygon is a polygon shape more than a triangle, Preferably, it is a square and a hexagon.

  In the present invention, the reference wire diameter of a wire is a wire diameter corresponding to the winding thickness of the wire. For example, if the cross section of the wire is circular, the reference wire diameter is the outer diameter of the wire, if it is a triangle, it is the height from the base to the corresponding vertex, and if it is a rectangle, It is the distance from the base to the corresponding top side, in the case of a pentagon, it is the distance from the base to the corresponding vertex, and in the case of a hexagon, it is the distance from the base to the corresponding top side. Hereinafter, the same definition applies to a heptagon or more.

  In the present invention, the reference outer diameter of the core portion is a simple outer diameter when the cross section of the core portion is circular, and is defined in the same manner as the reference wire diameter of the wire when it is polygonal. Is done.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 is a longitudinal sectional view of a wound electronic component according to an embodiment of the present invention.
2 is a schematic diagram of the drum core shown in FIG.
FIG. 3A is a cross-sectional view showing the main part of the winding portion of the wire shown in FIG.
FIG. 3B is a cross-sectional view showing the main part of the wire winding portion according to the conventional example,
4A is a cross-sectional view of the main part of the IVA part shown in FIG. 1, and FIG. 2B is a cross-sectional view of the main part of the IVB part shown in FIG.

  As shown in FIG. 1, a wound electronic component 2 according to an embodiment of the present invention has a drum core 4 as a core member (core material). The drum core 4 is made of a ferrite material. The drum core 4 has a core part 4 a in which a wire 10 a constituting the coil part 10 is wound along the axial direction of the core 4.

  A first flange 4b and a second flange 4c are integrally formed at the first end and the second end, which are both ends in the axial direction of the core 4a. The outer diameters of the first flange 4b and the second flange 4c are larger than the outer diameter of the core part 4a.

  The cross section of the core part 4a is not particularly limited, and may be a square cross section, a circular cross section, or other cross sectional shapes. The cross-sectional shapes of the first flange 4b and the second flange 4c are not particularly limited, and may be a rectangular cross-section, a circular cross-section, or other cross-sectional shapes. The first flange 4b and the second flange 4c have the same size. For example, in the case of a quadrangular section, the length is about 0.20 to 5.20 mm and the width is about 0.20 to 5.20 mm.

  In the present embodiment, as shown in FIGS. 1, 2, and 3A, the cross-sectional shape of the wire 10a is a square. As shown in FIG. 3A, the reference wire diameter D of the wire 10a is the same as the winding thickness t0 of the wire 10a after winding, and is defined as the height from the bottom side to the top side of the quadrangle. The reference wire diameter D is preferably 0.010 to 0.200 mm.

  As shown in FIG. 3A, the wire 10a includes a conducting wire portion 100 having a quadrangular cross section and an insulating coating layer 102 covering the outer periphery thereof. The conductor portion is made of a conductive material such as copper, gold, silver, or platinum. The insulating coating layer 102 is made of polyurethane resin, polyester resin, polybutyral resin, butadiene resin, imide resin, amide resin, or the like. The thickness of the insulating coating layer 102 is preferably 3 to 15 μm.

  In the present embodiment, as shown in FIG. 2, the reference outer diameter Φc at the central portion in the axial direction of the core portion 4a is made larger than the reference outer diameter Φe at both axial ends of the core portion 4a. In the longitudinal section including the axis of the core portion 4a, the outer peripheral shape of the core portion 4a is an arc shape having a radius R. The radius R is preferably 1.00 to 10.00 mm.

Moreover, in the present embodiment, the reference outer diameter Φc at the axial center of the core portion 4a and the axial direction of the core portion 4a with respect to the reference wire diameter D of the wire 10a so as to satisfy the following relational expression: The reference outer diameter Φe at both ends is designed. That is,
0 <Φc−Φe ≦ 2 × D,
Preferably, a relationship of 0.5 × D ≦ Φc−Φe ≦ 1.5 × D is set.

  The reference outer diameter Φc at the axial center of the core 4a is preferably about 0.10 to 2.50 mm, and the total axial length L0 of the drum core 4 is about 0.50 to 5.60 mm. .

  As shown in FIG. 1, the connecting portions 10b and 10c formed at both ends of the wire 10a constituting the coil portion 10 are connected to the base electrode layer 20 at the outer peripheral positions of the flanges 4b and 4c. The connecting portions 10b and 10c of the wire 10a are secured after the base electrode layer 20 is formed on the outer periphery and end surfaces of the flanges 4b and 4c. Alternatively, the connecting portions 10b and 10c of the wire 10a may be connected to the base electrode layer 20 after the base electrode layer 20 is formed on the outer periphery and end surfaces of the flanges 4b and 4c.

  The base electrode layer 20 can be obtained by applying and forming an electrode paste containing conductive particles such as Ag, glass frit and binder resin, followed by drying and baking. Although the drying temperature in that case is not specifically limited, 100-300 degreeC and baking temperature are about 600-800 degreeC. The film thickness of the base electrode layer 20 after the baking treatment is not particularly limited, but is usually about 20 to 60 μm.

  After the base electrode layer 20 and the connecting portions 10b and 10c are connected, a resin coating is formed by molding a resin in the outer peripheral concave portion of the core portion 4a where the coil portion 10 is formed. The outer diameter of the resin coating portion 50 is approximately the same as the outer diameter of the flanges 4b and 4c. The resin covering portion 50 is formed so as not to cover the wire connecting portions 10 b and 10 c, but may be formed so as to close the gap between the flanges 4 b and 4 c and the resin covering portion 50.

  It does not specifically limit as resin which comprises the resin coating part 50, An epoxy resin, a phenol resin, a polyester resin etc. are illustrated.

  As shown in FIGS. 1 and 2, after the resin coating portion 50 is formed, the outer peripheral surface and the outer end surface of the base electrode layer 20 are covered, and the gap between the flanges 4 b and 4 c and the resin coating portion 50 is closed. Then, a conductive paste film (conductive electrode film) 30 is formed. The conductive paste film 30 is formed by applying a conductive paste and then drying it. The conductive paste in this case includes, for example, conductive particles such as Ag, a binder resin, a solvent, and the like. Drying after the application of the conductive paste is performed under temperature conditions such that the resin coating 50 does not deteriorate.

  In the present embodiment, after applying the conductive paste, a thinner conductive paste film 30 is formed on the outer end surfaces of the flanges 4b and 4c than the outer peripheral portions of the flanges 4b and 4c. First, a conductive paste is applied to the outer peripheral surface and the outer end surface of one flange 4b by, for example, a dipping method to form a paste film.

  Thereafter, before these paste films are dried, only the paste film 30a formed on the outer end face portion of the flange 4b is pressed against a water absorbent sheet or the like to absorb the paste film 30a. Although it does not specifically limit as a water absorbing sheet, The paper material, woven fabric, nonwoven fabric, etc. which have water absorption are illustrated.

  Thereafter, when the outer end face of the flange 4b is separated from the water absorbent sheet, most of the paste film 30a formed on the outer end face is absorbed by the water absorbent sheet. As a result, the thickness of the paste film 30a located on the outer end face of the flange 4b is extremely thinner than the thickness of the paste film 30b on the outer peripheral portion of the flange 4b. Thereafter, after the paste film 30 is dried, the paste film 30 is similarly formed on the outer end face and the outer peripheral face of the flange 4c.

  In the conductive paste film 30 thus formed, as shown in FIG. 4A, the thickness t1 of the paste film 30a on the outer end face portion of the flanges 4b and 4c is 0 to 10 μm, preferably 0 to 6 μm. More preferably, it is extremely thin as 0 to 5 μm. Further, as shown in FIG. 4B, the paste film 30b on the outer periphery of the flanges 4b and 4c is about 20 to 50 μm.

  Thereafter, as shown in FIG. 1, an outer electrode film 40 made of a plating film is formed outside the conductive paste film 30. Although the outer electrode film 40 may be a single layer, in this embodiment, as shown in FIG. 4B, the outer electrode film 40 is composed of three layers of plating films 42 to 44. The three layers of plating films 42 to 44 are made of, for example, Cu, Ni, Sn, or the like.

  In the wound electronic component 2 according to this embodiment, the conductive paste film 30 is formed after the resin coating portion 50 is formed, but the thickness of the paste film 30a located on the outer end face of the flanges 4b and 4c is 0 to 0. It is extremely thin as 10 μm, preferably 0 to 6 μm, more preferably 0 to 5 μm. For this reason, even if the size of the wound electronic component 2 is reduced, variations in the axial length of the wound electronic component 2 can be suppressed.

  According to the experiments by the present inventors, when the thickness of the paste film 30a is 0 to 10 μm, the variation can be within 3.3%, and when the thickness of the paste film 30a is 0 to 6 μm. The variation can be within 2.0%. Further, when the thickness of the paste film 30a is 0 to 5 μm, the variation can be within 1.7%.

  Since the variation in the axial length dimension of the wound electronic component 2 can be suppressed, the land size and error of the board portion on which the wound electronic component 2 is mounted are less likely to occur, thus preventing mounting defects. can do. Further, in a printed circuit board or the like, it is not necessary to design the land pattern with a margin, and high mounting density is facilitated.

  Furthermore, in this embodiment, since the conductive paste film 30 is formed, even if the external electrode film 40 composed of a plating film is formed thereon, the base electrode layer 20 and the coating resin portion 50 The plating solution does not enter from the gaps between them, and various problems such as short circuit defects can be suppressed.

  In the present embodiment, the outer electrode film 40 composed of the plating films 42 to 44 is formed on the outer periphery of the conductive paste film 30. By forming the plating films 42 to 44, mounting on a substrate or the like becomes easy.

  In particular, in this embodiment, not only the cross section of the wire 10a is a square, but also the reference wire diameter D of the wire 10a, the reference outer diameter Φc at the axial center of the core, and both axial ends of the core. By making the reference outer diameter Φe in the portion have the above relationship, the winding wire 10a can be effectively prevented from being disturbed.

  That is, in the wound electronic component 2 according to the present embodiment, the reference outer diameter Φc at the axial center portion of the core portion 4a is relatively larger than the reference outer diameter Φe at both axial ends of the core portion. Become. Therefore, the wire 10a having a square cross-sectional shape wound around the winding core portion 4c is moved toward the both ends in the axial direction of the winding core portion 4a during the winding operation, and the wires 10a are not separated from each other. Wound densely in the state. Therefore, the winding disorder of the wire 10a is effectively prevented. Therefore, characteristics such as an inductance value and a magnetic flux density in the wire winding portion in the wound electronic component 2 are improved.

  In the wound electronic component 2 of the present embodiment, since the inductance value can be improved, the number of windings for obtaining the same inductance value can be reduced. If the number of windings can be reduced, the overall length of the wire 10a can be shortened, the direct current resistance can be reduced, and the size of the component 2 can be reduced.

  Moreover, in the wire wound electronic component 2 according to the present embodiment, since the cross section of the wire 10a is square, the reference outer diameter D is the same as that of the wire 10A having a circular cross section shown in FIG. In this case, the cross-sectional area of the conductor portion 100 in the wire 10a increases. Therefore, also in this respect, the DC resistance of the wound electronic component 2 can be reduced.

In the present embodiment, the cross-section of the wire 10a is rectangular, and (Φc−Φe) is set within a predetermined range, so that the adjacent wires 10a are vertically moved as shown in FIG. Adhere to the left and right. Therefore, as shown in FIG. 3B, it is not necessary to form the cement layer 104 formed on the outer periphery of the conventional wire 10A in the wire 10a of the present embodiment. Therefore, also in this respect, when the reference outer diameter D is the same, the cross-sectional area of the conductive wire portion 100 in the wire 10a increases, and the DC resistance R _DC of the wound electronic component 2 can be reduced.

  Furthermore, in this embodiment, as shown in FIG. 3A, since adjacent wires 10a are brought into close contact with each other by surface contact, even when the wires 10a are wound around two or more layers, they are positioned in the upper layer. It is also possible to prevent winding disturbance such as the wire 10a to fall between the wires 10a positioned in the lower layer. In contrast, conventionally, as shown in FIG. 3B, the wire 10A located in the upper layer is likely to be distorted such as falling between the wires 10A located in the lower layer. is there.

According to experiments of the present inventors, the cross-sectional shape of the wire 10a, by merely in a rectangular shape from a circular, only the DC resistance R _DC can be reduced by about 20%. However, in the embodiment of the present invention, the cross section of the wire 10a in a square shape, moreover, (.PHI.c-.PHI.e) to be to a predetermined range, by their synergistic effect, the DC resistance R _DC 21 to 29% While being able to reduce, an inductance value can be improved about 5 to 15%.

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 specific cross-sectional structure of the wound electronic component according to the present invention is not limited to the embodiment shown in FIG. 1 and can have various aspects. Further, the cross-sectional shape of the wire 10a is not limited to a quadrangle, and may be various shapes such as a triangle, a pentagon, and a hexagon.

  Further, as a method for making the thickness t1 of the paste film 30a located on the outer end face of each flange 4b, 4c thinner than the thickness t2 of the paste film 30b on the outer peripheral face, other than absorbing the paste with the water absorbent sheet The method is fine. As such a method, there is a method of scraping off the paste with a blade or the like.

FIG. 1 is a longitudinal sectional view of a wound electronic component according to an embodiment of the present invention. FIG. 2 is a schematic view of the drum core shown in FIG. 3A is a cross-sectional view showing the main part of the wire winding part shown in FIG. 1, and FIG. 3B is a cross-sectional view showing the main part of the wire winding part according to the conventional example. 4A is a cross-sectional view of the main part of the IVA part shown in FIG. 1, and FIG. 2B is a cross-sectional view of the main part of the IVB part shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Winding-type electronic component 4 ... Drum core 4a ... Core part 4b ... 1st flange 4c ... 2nd flange 10 ... Coil part 10a, 10A ... Wire 10b, 10c ... Connection part 100 ... Conducting wire part 102 ... Insulation coating layer 104 ... Cement layer 20 ... Base electrode layer 30 ... Conductive paste film 30a ... Paste film located on outer end face 30b ... Paste film located on outer periphery 40 ... Outer electrode film 42, 43, 44 ... Plating film 50 ... Resin coating part

Claims (5)

A core portion having a pair of flanges at both axial ends of the core portion;
A wire wound around the core portion;
A wire-wound electronic component having
The cross section of the wire is polygonal;
When the reference wire diameter of the wire is D, the reference outer diameter at the axial center of the core is Φc, and the reference outer diameter at both axial ends of the core is Φe,
A wound electronic component having a relationship of 0 <Φc−Φe ≦ 2 × D.   The wire wound electronic component according to claim 1, wherein the wire has a square cross section.   The wire-wound electronic component according to claim 1, wherein the wire has a rectangular cross section.   The wound electronic component according to any one of claims 1 to 3, wherein an insulating coating layer is formed on an outer periphery of the wire.   The wound-type electron according to any one of claims 1 to 4, wherein a reference outer diameter of the core portion gradually changes from an axial center portion of the core portion toward both axial ends of the core portion. parts.

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