JP2016143834A - Magnetic core and coil device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic core, suppressing plating extension, excellent in voltage resistance characteristics and a coil device.SOLUTION: At a corner part where an external surface 8a and side surfaces 8b and 8c of a flange part 8 positioned between a pair of terminal electrode formation scheduled parts 20 cross, a plating extension part such as a recess part 30C or a step part is formed.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a magnetic core and a coil device, and more particularly to a magnetic core and a coil device that can improve a withstand voltage.

  A magnetic core is known in which hooks are formed at both ends of the core part, and a pair of terminal electrodes are formed on the outer surface of the hook (see Patent Document 1). Lead terminals of wires wound around the winding core are connected to the terminal electrodes, respectively.

  The terminal electrode is formed by, for example, a plating method. However, plating elongation occurs on the surface of the magnetic core between the terminal electrodes, and the withstand voltage characteristic of the coil device may be deteriorated. In particular, recently, a metal magnetic material may be used as the magnetic core, and in this case, there is a problem that the plating elongation tends to occur particularly on the surface of the magnetic core between the terminal electrodes.

JP-A-9-153419

  The present invention has been made in view of such a situation, and an object thereof is to provide a magnetic core and a coil device that suppress plating elongation and have excellent withstand voltage characteristics.

  As a result of intensive studies on the magnetic core and the coil device that can suppress the plating elongation, the present inventors have found that the corner portion where the outer surface and the side surface of the collar portion located between the pair of terminal electrode formation scheduled portions intersect. In addition, the inventors have found that the plating elongation can be suppressed by forming a plating elongation preventing portion such as a concave portion or a stepped portion, thereby completing the present invention.

That is, the magnetic core according to the present invention is
A magnetic core having a winding core and a collar,
On the outer surface and / or side surface of the flange portion, there is a pair of electrode planned portions where terminal electrodes are to be formed,
A plating elongation preventing portion is formed at a corner where the outer surface and the side surface of the flange portion located between the pair of electrode planned portions intersect.

  In the magnetic core according to the present invention, even if the terminal electrode is formed by using the barrel plating method, the impact during the barrel plating does not reach the plating elongation preventing portion. Therefore, an insulating layer such as an oxide film, a glass film, or a resin film remains in the plating elongation preventing portion, and the plating elongation preventing portion prevents the plating elongation. As a result, the withstand voltage characteristic of the magnetic core is improved.

  In particular, when the magnetic core is a metal-based magnetic core (compact molding), plating elongation tends to occur. However, the magnetic core of the present invention is particularly effective because there is a plating elongation preventing portion. In addition, plating elongation can be prevented.

  Preferably, the plating elongation preventing portion is a concave portion or a step portion formed in the corner portion. The step portion is formed at the end of the concave or convex portion. The corner portion is the portion where the impact is most applied due to the collision between the cores during barrel plating or the collision between the core and the medium. The insulating layer is easily removed, and the plating is likely to be elongated. By forming the concave portion or the step portion at the corner portion, no impact is applied to the concave portion or the step portion, and the insulating layer remains in the concave portion or the step portion. Therefore, the plating extension is prevented by the concave portion or the step portion.

  Preferably, the plating elongation preventing portion is formed in each of the corner portions located near the pair of planned electrode portions. A terminal electrode is formed in the planned electrode portion, but the plating elongation can be minimized by disposing the plating elongation preventing portion near the planned electrode portion.

  The plating elongation preventing portion may be formed continuously from the corner portion of the flange portion to the side surface and parallel to the terminal electrode, and / or from the corner portion of the flange portion. It may be formed continuously on the outer surface and parallel to the terminal electrode. By forming the plating elongation preventing portion within such a range, the plating elongation can be suppressed at least in the portion where the plating elongation preventing portion is formed.

  Preferably, the flange portion is integrally formed on both ends of the core portion, and the plating elongation preventing portion is formed on the flange portion where the terminal electrode is not formed. It is formed at the same position as the buttock. By comprising in this way, a terminal electrode may be formed in the outer surface of any collar part, and the formation workability of a terminal electrode improves.

  Preferably, the terminal electrode is formed by plating in each of the planned electrode portions.

The coil device of the present invention has the magnetic core described above,
A wire is wound around the core part, and lead ends of the wire are connected to the terminal electrodes, respectively.

  In the coil device of the present invention, an insulating layer such as an oxide film, a glass film, or a resin film remains in the plating elongation preventing portion formed of the concave portion or the step portion, and the plating elongation prevention portion prevents the plating elongation. As a result, the withstand voltage characteristic of the coil device is improved.

FIG. 1A is a partially cutaway perspective view of a coil device according to an embodiment of the present invention. FIG. 1B is a perspective view of the coil device shown in FIG. 1 as viewed from the bottom side. FIG. 1C is a perspective view of a magnetic core with terminal electrodes according to another embodiment of the present invention viewed from the bottom side. FIG. 2 is a bottom view of a magnetic core according to an embodiment of the present invention. 3A is a bottom view of the magnetic core showing the effect of suppressing the plating elongation of the magnetic core according to one embodiment of the present invention, and FIG. 3B is an enlarged view of the main part of IIIB shown in FIG. 3A. is there. 4A to 4C are bottom views of a magnetic core according to another embodiment of the present invention. FIG. 5 is a perspective view seen from the bottom side of a coil device according to another embodiment of the present invention. FIG. 6 is a perspective view of a coil device according to still another embodiment of the present invention as viewed from the bottom side. FIG. 7 is a perspective view of a coil device according to still another embodiment of the present invention as viewed from the bottom side. FIG. 8 is a perspective view of a coil device according to still another embodiment of the present invention as seen from the bottom side.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

First Embodiment As shown in FIGS. 1A and 1B, a coil device 1 according to an embodiment of the present invention has a magnetic core 2. The magnetic core 2 has a core portion 4 around which the wire 12 is wound, and flanges 6 and 8 that are respectively located at both ends of the core portion 4 in the axial direction (Z-axis direction). It is molded integrally.

  In the present embodiment, the winding core portion 4 has a cylindrical shape, and the wire 12 is wound in a single layer or a plurality of layers around the winding core portion 4 to constitute the coil portion 10. However, the core part 4 is not limited to a cylindrical shape, and may be an elliptical column shape, a prismatic shape, or other shapes. Moreover, although the collar parts 6 and 8 are rectangular plate shapes in this embodiment, any shape can be used as long as it is a polygonal plate shape, a disk shape, an elliptical plate shape, or any other size larger than the core portion 4. Such a shape may be used. For example, a magnetic core 2A having a shape as shown in FIG. 1C may be used.

  The flanges 6 and 8 do not necessarily have the same shape as each other, but have the same shape in the present embodiment. The size of the coil device 1 is not particularly limited, but the length (X-axis direction) is 0.4 to 20 mm, the width (Y-axis direction) is 0.2 to 20 mm, and the height (Z-axis direction) is. 0.2 to 15 mm. Note that the X axis, the Y axis, and the Z axis are perpendicular to each other.

  In the present embodiment, of the two flange portions 6 and 8, the back side outer surface 8a of the flange portion 8 on the side where the coil device 1 is mounted is insulated at a predetermined distance on both sides in the X-axis direction. Shaped terminal electrodes 24 and 26 are formed. The terminal electrode 24 is formed continuously from the electrode body 24a fixed to the back side outer surface 8a of the flange 8 and both ends of the electrode body 24a in the Y-axis direction. And auxiliary electrode pieces 24b fixed to the opposite side surfaces 8b and 8c.

  Similarly to the terminal electrode 24, the terminal electrode 26 is formed continuously from the electrode body 26a fixed to the back side outer surface 8a of the flange portion 8 and both ends of the electrode body 26a in the Y-axis direction. And the auxiliary electrode piece 26b fixed to the side surfaces 8b and 8c facing the Y-axis direction of the portion 8. On the auxiliary electrode pieces 24b and 26b formed on one side surface 8b in the Y-axis direction, both ends 12a and 12b of the wire 12 wound around the coil portion 10 are respectively formed by laser welding, resistance welding, or soldering. Connected. Note that both ends 12a and 12b of the wire 12 may be directly connected to electrode bodies 24a and 26a fixed to the back outer surface 8a of the flange portion 8.

  In the present embodiment, the wire 12 is not particularly limited, and may be a single wire or a stranded wire. Examples of the material include copper, silver, gold, and alloys thereof. Further, the cross section of the wire 12 is not limited to a circle, but may be a flat section. These wires 12 are preferably covered with insulation at portions other than both ends 12a and 12b connected to the auxiliary electrode pieces 24b and 26b. The winding method of winding the wire 12 around the core part 4 is not particularly limited.

  In the present embodiment, the magnetic core 2 has a fine structure in which a large number of metal particles are insulated from each other by an inorganic insulating coating as an insulating phase, for example. The metal particles constituting the magnetic core 2 are not particularly limited as long as they are magnetic metals. For example, Fe-Ni alloy powder, Fe-Si alloy powder, Fe-Si-Cr alloy powder, Fe-Si-Al alloy Examples thereof include powder, permalloy powder, amorphous powder, and Fe powder. These ferromagnetic metal powders have a higher saturation magnetic flux density than ferrite powders, and the DC superposition characteristics are maintained up to a high magnetic field. Therefore, these ferromagnetic metal powders are suitable for easy handling of large currents and high conversion efficiency.

  The inorganic insulating film covering the metal particles is composed of, for example, a silicon oxide film, a metal oxide film, a glass film, or the like. Although the particle size of a metal particle is not specifically limited, Preferably it is an average particle diameter of 0.5-100 micrometers. Although the film thickness of an inorganic insulating film is not specifically limited, Preferably it is 1 / 1000-1 / 10 of the particle size of a metal particle. Although the metal particles themselves have electrical conductivity, the metal particles are insulated from each other by an insulating coating, and the entire magnetic core 2 can be said to be an insulator.

  The magnetic core 2 of this embodiment is a sintered body, and is obtained by firing granulated powder containing metal particles into a predetermined shape after being pressure-molded in a mold. The molding method is not limited to this embodiment. For example, injection molding, extrusion molding, lamination molding, transfer molding and the like are exemplified. By firing the core molded body before firing at, for example, 600 to 1100 ° C., the magnetic core 2 after firing is obtained.

  In the present embodiment, as shown in FIG. 2, there is a pair of planned electrode portions 20 on which the terminal electrodes 24 and 26 are to be formed on the rear outer surface 8 a of the flange portion 8. Four concave portions 30 as plating elongation preventing portions are formed at corners where the back-side outer surface 8a and the side surfaces 8b, 8c of the flange portion 8 positioned between the pair of electrode planned portions 20 intersect. As shown in FIGS. 1A and 1B, these concave portions 30 are formed on both side surfaces 8b and 8c of the flange portion 8 near the auxiliary electrode piece 24b of the terminal electrode 24 in the Z-axis direction substantially in parallel with them. It is formed linearly along.

  As shown in FIG. 2, in this embodiment, the cross section of each recess 30 is semicircular, and the groove depth D1 is D1 / Wy when the width in the Y-axis direction of the flange portion 8 is Wy. Is preferably determined to be 0.02 to 0.05. If the groove depth is too small, the effect of the present embodiment tends to be small, and if it is too large, the volume of the magnetic core decreases and the magnetic characteristics tend to deteriorate. The groove depth D1 of each recess 30 is preferably the same, but may be different.

  In addition, the groove width W1 of each recess 30 is not particularly limited, but is preferably smaller than the thickness in the Z-axis direction of each of the flange portions 6 and 8, and the X-axis direction gap width between the planned electrode portions 20 is defined as W2. In this case, it is preferable that W1 / W2 is determined to be 0.05 to 0.1. The groove width W1 of each recess 30 is preferably the same, but may be different. If the groove width is too small, the effect of the present embodiment tends to be small, and if the groove width is too large, the volume of the magnetic core tends to decrease and the magnetic characteristics tend to deteriorate.

  The X-axis direction width W3 of the planned electrode portion 20 is not particularly limited, but when the X-axis direction width of the flange portion 8 is Wx, W3 / Wx is 0.2 to 0.3. Preferably it is determined. The X-axis direction width W3 of the pair of electrode planned portions 20 is preferably the same, but may be different.

  Each of the recesses 30 is formed near the planned electrode portion 20 on the side surfaces 8 b and 8 c of the flange portion 8. The concave portion 30 may overlap the planned electrode portion 20, and when the distance between the central portion of each concave portion 30 in the X-axis direction and the edge of the planned electrode portion 20 is W4, W4 / W2 is 0 to 0. .1 is preferable.

  In this embodiment, as shown in FIG. 1A and FIG. 1B, the recess 30 may be formed only in the flange 8 where the terminal electrodes 24 and 26 are formed. The recess 30 is preferably formed at the same position as the flange 8. That is, it is preferable that the concave portion 30 is formed at the same position as the flange portion 8 on the side surfaces 6b and 6c that intersect the upper outer surface 6a of the flange portion 6 via the corner portion. The recess 30 may be formed at the same time as the magnetic core 2 is molded, but may be formed by cutting or the like after the molding.

  The cross-sectional shape of the recess 30 is not particularly limited. For example, as shown in FIG. 4A, the cross-sectional shape may be a rectangular cross-section, as shown in FIG. 4B, an inverted triangular cross-section, and FIG. As shown, a quarter-circle fan shape may be used.

  Next, a method for forming the terminal electrodes 24 and 26 on the planned electrode portion 20 of the magnetic core 2 shown in FIGS. 1A and 1B will be described.

  First, a metal powder such as Ag and glass frit are applied to the planned electrode portion 20 of the magnetic core 2 where the terminal electrodes 24 and 26 are to be formed, and heat treatment (firing) is performed to form a base electrode.

  Next, in this embodiment, a desired plating film is deposited on the surface of the planned electrode portion 20 on which the base electrode is formed by barrel plating to form the terminal electrodes 24 and 26 having a predetermined thickness. The plating film may be a single layer or multiple layers. For example, a plating film such as Ni—Sn plating, Cu—Ni—Sn plating, Sn plating, Ni—Au plating, or Au plating is formed. The thickness of the terminal electrodes 24 and 26 is not particularly limited, but is preferably 0.1 to 15 μm.

  The wire 12 is wound around the core portion 4 of the magnetic core 2 on which the terminal electrodes 24 and 26 are formed. Next, both the lead ends 12a and 12b of the wire are connected to the auxiliary electrode pieces 24b and 26b by laser welding, resistance welding or soldering, respectively.

  After the wire 12 is wound around the core 4 and the lead ends 12a and 12b of the wire are connected to the auxiliary electrode pieces 24b and 26b, the space between the flanges 6 and 8 is filled with the exterior resin 40. The exterior resin 40 is preferably composed of a resin containing metal powder. The metal powder may be the same as or different from the metal powder constituting the magnetic core 2. By embedding the exterior resin 40 of a high magnetic permeability material between the flange portions 6 and 8, magnetic characteristics such as inductance of the coil device 1 are improved.

  In the magnetic core 2 according to the present embodiment, even if the terminal electrodes 24 and 26 are formed using the barrel plating method, the impact during the barrel plating does not reach the recess 30. Therefore, an oxide film remains in the recess 30, and the plating extensions 24 c and 26 c are prevented by the recess 30 as shown in FIGS. 3A and 3B. As a result, the withstand voltage characteristic of the magnetic core 2 is improved.

  In particular, when the magnetic core 2 is a metal-based magnetic core (compact molding), the plating tends to easily extend. However, in the magnetic core 2 of the present embodiment, since the recess 30 is present, Effectively preventing plating elongation.

  In general, in the magnetic core 2, the corners between the outer surface 6a and the side surfaces 6b and 6c, the corners between the outer surface 8a and the side surfaces 8b and 8c, and other corners are formed between the cores during barrel plating. This is the portion where the impact is most applied due to the collision or the collision between the core and the medium, and the insulating layer is easily removed and the plating is likely to be elongated. In the present embodiment, by forming the concave portion 30 in the corner portion, no impact is applied to the inside of the concave portion 30, and an insulating layer such as an oxide film remains in the concave portion 30. Therefore, as shown in FIGS. 3A and 3B, the plating extensions 24c and 26c are blocked by the recess 30.

  In addition, as shown in FIG. 2, the recesses 30 are respectively formed along the Z-axis direction on the side surfaces 8 b and 8 c located near the pair of planned electrode portions 20. A terminal electrode is formed on the planned electrode portion 20, but the plating elongation can be minimized by disposing the recess 30 near the planned electrode portion 20.

  Further, in the present embodiment, as shown in FIGS. 1A and 1B, the upper flange 6 where the terminal electrodes 24 and 26 are not formed is also in the same position as the lower flange 8 where the terminal electrodes 24 and 26 are formed. Is formed. By comprising in this way, the terminal electrodes 24 and 26 may be formed in the outer surface of any collar part 6 and 8, and the formation workability of a terminal electrode improves.

  In the above-described embodiment, the terminal electrodes 24 and 26 are continuously formed not only on the bottom surface 8a of the flange portion 8 but also on the side surfaces 8b and 8c, but may be formed only on one of the surfaces. good. Further, the positions where the terminal electrodes 24 and 26 are formed are not particularly limited.

Second Embodiment As shown in FIG. 5, in the coil device 1B according to the second embodiment of the present invention, the position where the recess 30B is formed in the magnetic core 2B is smaller than that of the coil device 1 of the first embodiment. Except for the difference, the coil device 1 has the same configuration as that of the first embodiment, and has the same effects. Common members are denoted by common reference numerals, and description thereof is omitted.

  As shown in FIG. 5, in the present embodiment, not the side surfaces 8 b and 8 c of the flange portion 8, but on the outer surface 8 a, between the pair of planned electrode portions 20, near the terminal electrodes 24 and 26, and in parallel therewith. A recess 30B is formed substantially parallel to the Y-axis direction. Similarly to the flange portion 8, the recess portion 30B is formed on the outer surface 6a of the flange portion 6 instead of the side surfaces 6b and 6c.

  Also in this embodiment, even if the terminal electrodes 24 and 26 are formed using the barrel plating method, the impact during the barrel plating does not reach the recess 30B. Therefore, an oxide film remains in the recess 30B, and the plating 30 which is likely to occur particularly at the corner is prevented by the recess 30B. As a result, the withstand voltage characteristic of the magnetic core 2 is improved.

Third Embodiment As shown in FIG. 6, in the coil device 1C according to the third embodiment of the present invention, the position where the recess 30C is formed in the magnetic core 2C as compared with the first and second embodiments described above. Except for the difference, they have the same configuration as those of these embodiments and have the same effects. Common members are denoted by common reference numerals, and description thereof is omitted.

  As shown in FIG. 6, in the present embodiment, not the side surfaces 8b and 8c of the flange portion 8 but the outer surface 8a of the flange portion 8 but these corner portions 8ab and 8ac, and a pair of electrodes A recessed portion 30 </ b> C is formed between the planned portions 20 near the terminal electrodes 24 and 26. Further, similarly to the flange portion 8, the recess portion 30C is formed only in the corner portions 6ab and 6ac, not the side surfaces 6b and 6c and the outer surface 6a.

  Also in this embodiment, even if the terminal electrodes 24 and 26 are formed by using the barrel plating method, the impact during the barrel plating does not reach the concave portion 30C. Therefore, an oxide film remains in the recess 30C, and the plating extension that is likely to occur particularly in the corner portions 6ab, 6ac, 8ab, and 8ac is prevented by the recess 30C. As a result, the withstand voltage characteristic of the magnetic core 2 is improved.

Fourth Embodiment As shown in FIG. 7, the coil device 1D according to the fourth embodiment of the present invention is different from the first to third embodiments described above except for the following points. It has a configuration similar to that of the form and has the same effects. Common members are denoted by common reference numerals, and description thereof is omitted.

  In the present embodiment, as shown in FIG. 7, a recess 32 that is wide in the X-axis direction is formed on the outer surface 8a so as to extend in the Y-axis direction at the center in the X-axis direction. Step portions 30D are formed along the Y-axis direction at both ends in the direction near the terminal electrodes 24 and 26. It is preferable that the step depth of the step portion 30D is determined in the same manner as the depth of the concave portion 30 in the first embodiment.

  In addition, a wide concave portion 30 </ b> D is formed on the outer surface 6 a in the same manner as the flange portion 8 with respect to the flange portion 6. Also in the present embodiment, even if the terminal electrodes 24 and 26 are formed using the barrel plating method, the impact during the barrel plating does not reach the inside of the step portion 30D. Therefore, an oxide film remains in the stepped portion 30D, and the stepped portion 30D prevents plating extension that is likely to occur particularly in the corner portions 6ab, 6ac, 8ab, and 8ac. As a result, the withstand voltage characteristic of the magnetic core 2 is improved.

Fifth Embodiment As shown in FIG. 8, the coil device 1E according to the fifth embodiment of the present invention is different from the first to fourth embodiments described above except for the following points. It has a configuration similar to that of the form and has the same effects. Common members are denoted by common reference numerals, and description thereof is omitted.

  In this embodiment, as shown in FIG. 8, the convex part 34 wide in the X-axis direction is formed so as to extend continuously in the longitudinal direction at the center part in the X-axis direction continuously on the outer surface 8a and the side surfaces 8b and 8c. In addition, stepped portions 30E are formed along the longitudinal direction at both ends of the convex portion 34 in the X-axis direction, near the terminal electrodes 24 and 26. The step depth of the step portion 30E is preferably determined in the same manner as the depth of the concave portion 30 in the first embodiment.

  Similarly to the flange portion 8, a wide convex portion 30 </ b> E is formed on the flange portion 6 continuously to the outer surface 6 a and the side surfaces 6 b and 6 c. Also in this embodiment, even if the terminal electrodes 24 and 26 are formed by using the barrel plating method, the impact during the barrel plating does not reach the inside of the stepped portion 30E. Therefore, an oxide film remains in the stepped portion 30E, and the stepped portion 30E prevents plating extension that is likely to occur particularly in the corner portions 6ab, 6ac, 8ab, and 8ac. As a result, the withstand voltage characteristic of the magnetic core 2 is improved.

  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 magnetic core 2 does not necessarily need to be a sintered body, may be a molded body obtained by compacting, and may contain a synthetic resin. At the time of compacting, a molten synthetic resin in which metal particles are dispersed is poured into a mold, and the synthetic resin is cured by heat, for example. In that case, the magnetic core 2 is made of a synthetic resin in which the metal particles 30 are dispersed, and the synthetic resin becomes an insulating phase. Examples of the synthetic resin used for compacting include epoxy resins, urethane resins, acrylic resins, diallyl phthalate resins, silicone resins, polyimide amide resins, polyimide resins, and PVA resins.

  The entire outer surface of the magnetic core 2 may be covered with an insulating layer such as a glass film or a resin film. With such a configuration, even after barrel plating or after other impacts, the insulating layer remains in the recess or step portion, and the plating elongation can be blocked by the recess or step portion.

  In the above-described embodiment, the insulating layer remains in the concave portion or the stepped portion without applying an impact such as barrel plating, but it is also effective for methods other than barrel plating. For example, even when a plating film is formed by a method other than barrel plating, the insulating layer in the recess has a function of preventing plating elongation, and the plating elongation can be effectively suppressed. Furthermore, in the present invention, an insulating layer may be positively formed in the concave portion or the step portion so as to be thicker than other portions.

  In the present invention, as the plating elongation preventing portion, a concave portion and a step portion are exemplified, and unlike the concave portions 30, 30B to 30C, the step portions 30D and 30E are formed at both ends of the wide concave portion 32 or the convex portion 34. . Since the protrusion 34 itself is susceptible to an impact, when forming a stepped portion, it is preferable to form the recess 32 as shown in FIG.

  However, in the wide concave portion 32, since there is a risk that the insulation is removed by receiving an impact on the substantially central bottom surface of the concave portion 32, the concave portion as the plating elongation preventing portion is an electrode as shown in FIGS. 1A to 6. It is preferable to form each planned portion 20 with a minimum necessary amount. Deteriorating the magnetic properties of the magnetic core can be suppressed by minimizing the recesses.

  In addition, when providing a convex part in a magnetic core, or when a convex part is formed as a result by providing a recessed part, it is preferable not to make the width | variety of these convex parts too narrow. This is to prevent chipping due to impact or the like. Further, in the present invention, the stepped portion may be grasped as a kind of recessed portion as a stepped recessed portion.

DESCRIPTION OF SYMBOLS 1,1B-1E ... Coil apparatus 2, 2A-2E ... Magnetic core 4 ... Core part 6,8 ... Collar part 10 ... Coil part 12 ... Wire 20 ... Electrode planned part 24,26 ... Terminal electrode 30, 30B-30C ... Concave part 30D, 30E ... Step part 32 ... Wide concave part 34 ... Convex part 40 ... Exterior resin

Claims (9)

A magnetic core having a winding core and a collar,
On the outer surface and / or side surface of the flange portion, there is a pair of electrode planned portions where terminal electrodes are to be formed,
A magnetic core in which a plating elongation preventing portion is formed at a corner portion where an outer surface and a side surface of the flange portion located between a pair of the electrode planned portions intersect.   The magnetic core according to claim 1, wherein the plating elongation preventing portion is a concave portion or a step portion formed in the corner portion.   3. The magnetic core according to claim 1, wherein the plating elongation preventing portion is formed in each of the corner portions located near a pair of the electrode planned portions.   The magnetic core according to any one of claims 1 to 3, wherein the plating elongation preventing portion is formed continuously from the corner portion of the flange portion to the side surface and in parallel with the terminal electrode.   5. The magnetic core according to claim 1, wherein the plating elongation preventing portion is formed continuously from the corner portion of the flange portion to the outer surface and parallel to the terminal electrode. .   The magnetic core according to claim 1, wherein an insulating layer remains at least in the plating elongation preventing portion.   The flange portion is integrally formed on both ends of the core portion, and the plating elongation preventing portion is formed on the flange portion on which the terminal electrode is not formed and the flange portion on which the terminal electrode is formed. The magnetic core according to claim 1, wherein the magnetic core is formed at the same position.   The magnetic core according to any one of claims 1 to 7, wherein the terminal electrodes are formed by plating on the planned electrode portions. A coil device having the magnetic core according to claim 8,
A coil device in which a wire is wound around the core, and lead ends of the wire are connected to the terminal electrodes, respectively.

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