JP2016025150A - Toroidal coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toroidal coil suitable for mass production.SOLUTION: A toroidal coil 1 includes a core 10 forming an annular shape, and a coil 20. A spiral groove with a central axis of the annular shape formed by the core 10 is formed on the surface of the core 10. The coil 20 comprises a conductor provided so as to fill the groove.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a toroidal coil.

  As a conventional toroidal coil, a surface-mounted winding component described in Patent Document 1 is known. The manufacturing process of this type of toroidal coil (hereinafter referred to as a conventional toroidal coil) includes a winding process of winding a conducting wire around an annular core. However, since the core has an annular shape, it is difficult to automate the winding process, and as a result, the conventional toroidal coil is not suitable for mass production.

JP 2002-118019 A

  An object of the present invention is to provide a toroidal coil suitable for mass production.

The toroidal coil according to one aspect of the present invention is
A core having an annular shape, and a core having a spiral groove formed on the surface, the central axis being the annular shape;
A coil composed of a conductor provided so as to fill the groove;
Providing
It is characterized by.

  In the toroidal coil according to one embodiment of the present invention, a spiral groove is formed on the surface of the core. And the coil is comprised with the conductor provided so that this groove | channel might be filled up. Therefore, the toroidal coil according to one embodiment of the present invention can be manufactured by applying or printing a conductor paste in a groove provided on the surface of the core. That is, the manufacturing process of the toroidal coil according to one embodiment of the present invention does not require a winding process of winding a conducting wire around the annular core. Therefore, the toroidal coil according to one embodiment of the present invention is suitable for mass production as compared with a conventional toroidal coil.

  According to the present invention, mass productivity of toroidal coils can be improved.

It is the external view which looked at the toroidal coil which is one Example from the direction parallel to the cyclic | annular center axis | shaft which the core of this toroidal coil comprises. It is the external view which looked at the toroidal coil which is one Example from the direction orthogonal to the cyclic | annular center axis | shaft which the core of this toroidal coil comprises. It is the external view which looked at the toroidal coil which is one Example from the direction opposite to FIG. It is the external view which looked at the core of the toroidal coil which is one Example from the direction parallel to the cyclic | annular central axis which the core of this toroidal coil comprises. It is the external view which looked at the core of the toroidal coil which is one Example from the direction orthogonal to the cyclic | annular central axis which the core of this toroidal coil comprises. It is the external view which looked at the toroidal coil which is a 1st modification from the direction parallel to the cyclic | annular center axis which the core of this toroidal coil comprises. It is the external view which looked at the toroidal coil which is a 2nd modification from the direction parallel to the cyclic | annular center axis which the core of this toroidal coil comprises. It is the external view which looked at the toroidal coil which is a 2nd modification from the direction orthogonal to the cyclic | annular center axis which the core of this toroidal coil comprises. It is sectional drawing which shows the mounting state at the time of mounting the toroidal coil which is a 2nd modification on a circuit board. It is the external view which looked at the toroidal coil which is a 3rd modification from the direction parallel to the cyclic | annular center axis which the core of this toroidal coil comprises. It is the external view which looked at the toroidal coil which is a 3rd modification from the direction orthogonal to the cyclic | annular center axis which the core of this toroidal coil comprises. It is the external view which looked at the toroidal coil which is a 3rd modification from the direction orthogonal to the cyclic | annular center axis which the core of this toroidal coil comprises. It is sectional drawing of the groove | channel provided in the core of the toroidal coil. It is sectional drawing of the groove | channel provided in the core of the toroidal coil. It is sectional drawing of the groove | channel provided in the core of the toroidal coil. It is sectional drawing of the groove | channel provided in the core of the toroidal coil.

(Configuration of toroidal coil, see FIGS. 1 to 5)
As shown in FIGS. 1 and 3, the toroidal coil 1 according to one embodiment has an annular shape as a whole, and includes a core 10, a coil 20, and external electrodes 30 and 32. Further, the surface of the toroidal coil 1 is coated with glass or the like except for the external electrodes 30 and 32. Hereinafter, a direction parallel to the annular central axis formed by the core 10 is defined as an x-axis direction. One direction orthogonal to the x-axis direction is defined as the y-axis direction, and the direction orthogonal to the x-axis direction and the y-axis direction is defined as the z-axis direction.

  When the core 10 is viewed from the x-axis direction, the shape of the outer edge of the core 10 is a so-called saddle shape that combines a semicircle and a rectangle. Here, the rectangle is located on the negative direction side in the z-axis direction with respect to the semicircle. Accordingly, the negative end surface S1 of the core 10 in the z-axis direction is a flat surface. The core 10 is provided with a cylindrical hole H1 parallel to the x-axis direction near the center thereof. Thereby, the core 10 has an annular shape as a whole when viewed from the x-axis direction. Furthermore, when the core 10 is viewed from a direction orthogonal to the x-axis direction, the core 10 has a rectangular shape as shown in FIG.

The material of the core 10 is a magnetic material such as NiZn ferrite, MnZn ferrite, metal magnetic powder (Fe—Ni—Cr, Ni, permalloy, Fe—Si—Al powder), or a nonmagnetic material such as alumina. And the core 10 is obtained by sintering the above-mentioned material, or by making the resin contain the above-mentioned material in a powder form. Note that a sintered body or a molded body using MnZn-based ferrite or metal magnetic powder has low insulation resistance. Therefore, when such a material is used as the material of the core 10, it is desirable that the core 10 be insulated with SiO ₂ or the like.

  Further, as shown in FIGS. 4 and 5, a plurality of grooves G are formed on the surface of the core 10. These grooves G are connected to adjacent grooves and describe one spiral having a ring formed by the core 10 as a central axis. However, in the predetermined region A from the end surface S1 on the negative side in the z-axis direction to the positive direction side in the z-axis direction in the core 10, the groove G is parallel to the z-axis direction and does not draw a spiral. Of the plurality of grooves G, as shown in FIG. 5, the grooves provided on the surfaces located on the inner peripheral side and the outer peripheral side of the core 10 are provided in parallel with the x-axis direction.

  The coil 20 is composed of a conductor provided so as to fill the groove G. Since the groove G has a spiral shape as described above, the conductor functions as a coil by providing the groove G with a conductor buried therein. However, since the groove G is parallel to the z-axis direction in the predetermined region A described above, as shown in FIGS. 1 and 3, the conductor provided to fill this portion does not draw a spiral. The coil 20 is made of a conductive material such as a metal such as Ag or Cu, or a carbon nanotube with little change in characteristics due to temperature.

  The external electrodes 30 and 32 are made of a Ni-based alloy such as Ni—Cr, Ni—Cu, or Ni, Ag, Cu, AgPd, or the like. As shown in FIG. 1, the external electrode 30 is mainly provided at the end portion on the negative direction side in the y-axis direction on the end surface S <b> 1 of the core 10. A part of the external electrode 30 is provided so as to protrude from a surface adjacent to the end surface S1. The external electrode 32 is mainly provided at the end on the positive direction side in the y-axis direction on the end surface S1 of the core 10. A part of the external electrode 32 is provided so as to protrude from the surface adjacent to the end surface S1.

(Toroidal coil manufacturing method)
Below, the manufacturing method of the toroidal coil 1 is demonstrated.

  First, a powder whose main component is a magnetic material such as ferrite or a non-magnetic material such as alumina, which is a material of the core 10, is prepared. Fill the female mold with the prepared powder. By pressing the powder filled in the female mold with the male mold, the powder is formed into a so-called bowl-shaped shape combining a semicircle and a rectangle. At this time, portions corresponding to the hole H1 and the groove G of the core 10 are also formed. And the core 10 is completed by baking the powder shape | molded by the desired shape. In addition, when the core 10 is the molded object containing the said powder and resin, it shape | molds by press-molding and hardening the mixture of the said powder and resin. Further, the die cutting direction in this step is parallel to the central axis direction of the hole H1, that is, the x-axis direction in order to form the hole H1.

  Next, the coil 20 is formed. The coil 20 is formed by applying a conductive paste such as Ag, Cu, or AgPd to the groove G of the core 10, and drying and baking the paste.

  Then, external electrodes 30 and 32 are formed. In forming the external electrodes 30 and 32, first, a conductive paste such as Ag, Cu, or AgPd is applied to the end surface S <b> 1 of the core 10. Next, the attached Ag paste is dried and fired to form a conductive film as a base electrode on the end surface S1 of the core 10. The formation of the base electrode may be performed simultaneously with the formation of the coil 20. Furthermore, a Ni-based alloy metal film is formed on the Ag film by electroplating or the like. Thus, the external electrodes 30 and 32 are formed.

  Finally, the toroidal coil 1 is completed by forming a glass film on the surface by dipping, brushing, spray coating, or electrostatic powder coating with the external electrodes 30 and 32 masked.

(effect)
In the toroidal coil 1 which is one implementation, a spiral groove G is formed on the surface of the core 10. And the coil 20 is comprised with the conductor provided so that the groove | channel G might be filled up. Therefore, the toroidal coil 1 which is one Example can be manufactured by applying or printing a conductor paste in the groove G provided on the surface of the core 10. That is, when manufacturing the toroidal coil 1, the winding process of winding a conducting wire around the annular core is unnecessary. Therefore, the toroidal coil 1 is suitable for mass production as compared with the conventional toroidal coil.

  Of the grooves G provided on the surface of the core 10, the grooves provided on the surfaces located on the inner peripheral side and the outer peripheral side of the core 10 are provided in parallel with the x-axis direction. This is parallel to the die cutting direction of the core 10. Thus, by making the direction of the grooves provided on the inner circumferential side and the outer circumferential side of the core 10 parallel to the die cutting direction, the die can be smoothly cut and the groove G can be formed by a single press molding. All parts can be molded.

  Furthermore, in the toroidal coil 1 which is one implementation, the end surface S1 on the negative side in the z-axis direction of the core 10 is a flat surface, and external electrodes 30 and 32 are provided here. As a result, the toroidal coil 1 can be surface-mounted on a circuit board without mounting a surface-mounting board like a conventional toroidal coil.

  By the way, in the conventional toroidal coil, the external electrode is formed by crushing the end of the winding wound around the core. In this case, it is difficult to obtain an external electrode having a sufficient surface area. Therefore, soldering is not performed well, and there is a possibility that poor bonding occurs. On the other hand, in the toroidal coil 1, the external electrodes 30 and 32 are formed by applying a conductive paste to the core 10. Therefore, the external electrodes 30 and 32 have a sufficient surface area and can suppress poor bonding due to soldering.

  In addition, the surface of the toroidal coil 1 is coated with glass except for the external electrodes 30 and 32. Thereby, corrosion of the coil 20 can be suppressed, and a short circuit between the toroidal coil 1 and the circuit board on which the toroidal coil 1 is mounted can be prevented.

(First modification see FIG. 6)
The difference between the toroidal coil 1A which is the first modification and the toroidal coil 1 which is one embodiment is the shape of the core 10 and the number of turns of the coil 20. Specifically, as shown in FIG. 6, the toroidal coil 1A has a shape in which a rectangular parallelepiped and a ring are combined, and the rectangular parallelepiped and a part of the ring are combined. The shape of the portion where the rectangular parallelepiped and the ring are combined is such that the two protrusions 12 and 14 protrude from the predetermined portion of the ring toward both sides in the tangential direction.

  In the core 10 of the toroidal coil 1A configured as described above, since the area of the arc-shaped portion is larger than that of the toroidal coil 1 when viewed from the x-axis direction, the number of turns of the coil 20 can be increased. Other configurations of the toroidal coil 1A are the same as those of the toroidal coil 1. Therefore, in the toroidal coil 1 </ b> A, the description other than the shape of the core 10 is as described in the toroidal coil 1.

(Refer to 2nd modification FIGS. 7-9)
The differences between the toroidal coil 1B which is the second modification and the toroidal coil 1 which is one embodiment are the shape of the core 10, the shape of the end of the coil 20, and the configuration of the external electrodes. Specifically, the toroidal coil 1B has an annular shape as shown in FIG. Moreover, as shown in FIG. 8, it has two planes S2 and S3 orthogonal to the annular central axis L1. That is, the planes S2 and S3 are parallel to the y axis and the z axis. The two external electrodes 30 and 32 are provided adjacent to the plane S2.

  In the toroidal coil 1B configured as described above, the external electrodes 30 and 32 are provided on the surface S2 orthogonal to the annular central axis L1 formed by the toroidal coil 1B. By providing the external electrodes 30 and 32 in this way, as shown in FIG. 9, when the toroidal coil 1 is mounted on the circuit board 100, the ring formed by the toroidal coil 1B is parallel to the circuit board. Placed in. Therefore, the toroidal coil 1B does not require as much space in the height direction as the toroidal coil 1 when mounted on the circuit board. That is, the toroidal coil 1B contributes to a reduction in the height of the electronic component on which the toroidal coil 1B is mounted.

  By the way, in the toroidal coil 1, in order to connect the coil 20 and the external electrodes 30, 32, the periphery of both ends of the coil 20 forms a straight line parallel to the z-axis direction. On the other hand, the coil 20 in the toroidal coil 1 </ b> B has a spiral shape until just before the portion connected to the external electrodes 30 and 32. Therefore, the coil 20 in the toroidal coil 1 </ b> B has more portions that function as a coil than the coil 20 in the toroidal coil 1. Therefore, the toroidal coil 1 </ b> B can have an inductance value larger than that of the toroidal coil 1.

  In the toroidal coil 1B, since the external electrodes 30 and 32 are arranged adjacent to each other, most of the toroidal coil 1B can be used as a coil. Therefore, the inductance value can be increased as compared with the case where the external electrodes 30 and 32 are arranged apart from each other. Other configurations of the toroidal coil 1B are the same as those of the toroidal coil 1. Therefore, in the toroidal coil 1 </ b> B, descriptions other than the shape of the core 10, the shape of the end of the coil 20, and the configuration of the external electrodes are as described in the toroidal coil 1.

(Third Modification See FIGS. 10 to 12)
The difference between the toroidal coil 1C according to the third modification and the toroidal coil 1 according to one embodiment is that the external electrodes 30 and 32 are divided, and the groove G and the coil 22 provided on the surface of the core 10 are different. It is addition.

  The groove G provided on the surface of the core 10 of the toroidal coil 1 </ b> C is provided so that two spirals run in parallel with an annular shape formed by the core 10 as a central axis. Further, by providing a conductor so as to fill the groove G, the coil 22 is provided so as to run in parallel with the coil 20 as shown in FIGS. Further, in the toroidal coil 1C, as shown in FIG. 12, the external electrodes 30 and 32 are each divided in the x-axis direction. That is, the toroidal coil 1C includes four external electrodes. One of the divided external electrodes 30 is connected to the coil 20, and the other is connected to the coil 22. One of the divided external electrodes 32 is connected to the coil 20, and the other is connected to the coil 22.

  The toroidal coil 1C configured as described above functions as a toroidal transformer. Other configurations of the toroidal coil 1C are the same as those of the toroidal coil 1. Therefore, in the toroidal coil 1 </ b> C, the explanation other than the point where the external electrodes 30 and 32 are divided, the addition of the groove G provided on the surface of the core 10 and the coil 22 is the same as the explanation in the toroidal coil 1.

(Other examples)
The toroidal coil according to the present invention is not limited to the above embodiment, and can be variously modified within the scope of the gist thereof. For example, the core material, the coil material, the number of turns of the coil, and the like can be arbitrarily selected. For example, the material of the insulating coating in the toroidal coil 1 is not limited to glass, and may be a resin such as silicon, epoxy, polyimide, polyurethane, polyester, and polyesterimide.

  Further, the cross-sectional shape of the groove G may be chamfered at an angle E formed by the bottom surface S4 and the side surface S5 of the groove G as shown in FIG. 13, and the angle E is circular as shown in FIG. It may be made. Further, as shown in FIG. 15, the cross section of the groove G may be semicircular. As compared with the case where the cross-sectional shape of the groove G described above is a rectangular cross-sectional shape shown in FIG. From the effect that bubbles do not easily accumulate, the chamfering amount of the corner E is preferably 40 μm or more, or the radius of the arc of the corner E is preferably 40 μm or more and less than half the width of the groove G.

  As described above, the present invention is useful for toroidal coils and is excellent in that the mass productivity of toroidal coils can be improved.

S1 end face (plane)
S4 Bottom S5 Side E Square G Groove 1, 1A, 1B, 1C Toroidal coil 10 Core 20, 22 Coil 30, 32 External electrode

Claims (8)

A core having an annular shape, and a core having a spiral groove formed on the surface, the central axis being the annular shape;
A coil composed of a conductor provided so as to fill the groove;
Providing
Toroidal coil characterized by An external electrode connected to the coil;
A flat surface is formed on the core,
The external electrode is provided on the plane;
The toroidal coil according to claim 1. The corner formed by the bottom surface and the side surface in the cross section of the groove is chamfered,
The toroidal coil according to claim 1 or 2, wherein The angle formed by the bottom surface and the side surface in the cross section of the groove has an arc shape,
The toroidal coil according to claim 1 or 2, wherein The cross section of the groove is semicircular,
The toroidal coil according to claim 1 or 2, wherein The surface of the core is coated with insulation;
A toroidal coil according to any one of claims 1 to 5. The portions other than the external electrodes are insulated.
The toroidal coil according to any one of claims 1 to 6. The extending direction of the portion provided on the annular inner circumferential surface and the outer circumferential surface of the groove is substantially parallel to the annular central axis,
A toroidal coil according to any one of claims 1 to 7.

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