JPH06196335A - Inductor - Google Patents

Abstract

PURPOSE:To provide an inductor adapted for reduction in size of a square having 5mm or less of one side, high reliability and mass production. CONSTITUTION:The inductor comprises a T-shaped core 1 having a flat plate part and a central columnar part formed perpendicularly to the plate part, a core 2 in contact with an end face of the columnar part of the core 1 and the plate parts disposed at both sides of the end face of the columnar part to form a closed magnetic path, and a winding mounted at the columnar part of the core 1. The core 1 is adhered to the contact part of the core 1 for forming the magnetic path with adhesive 8 mixed with magnetic powder. A space formed by the core 1 and the core 2 for forming the magnetic path is filled with resin 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microminiature inductor including a transformer and a filter.

[0002]

2. Description of the Related Art As an inductor, a VTR integrated with a camera
With the miniaturization of electronic communication devices such as mobile radio devices and mobile phones, the demand for ultra-miniaturization has increased, and chip-shaped devices of about 5 mm square have also been used.

Conventionally, this type of inductor is generally EE
Type and E-I type cores are used, and in many cases, the bobbin is preliminarily wound and fitted into the central leg of the E type core. Also,
A bobbin type core having a winding wire and a laminated type using a printing technique are also known.

[0004]

However, the conventional EE
Type and E-I type core inductors, the bobbin needs strength for winding the bobbin itself, so it is difficult to downsize, and the winding is not easy to automate.
The limit was about mm mm. Further, with a bobbin type core, handling of the core is difficult, automation of winding is not easy, and miniaturization is difficult when a closed magnetic circuit type inductor is used. Further, it is known that the multilayer type inductor is miniaturized, but since the conductor wire is manufactured by printing, it is difficult in terms of reliability and manufacturing to secure the number of winding turns. Is superior.

An object of the present invention is to provide an inductor suitable for miniaturization of about 5 mm square or less, having high reliability and suitable for mass production.

[0006]

According to the present invention, a T-shaped core having a flat plate portion and a central columnar portion formed orthogonal to the flat plate portion, a tip surface of the central columnar portion of the T-shaped core and the An inductor characterized by comprising a core that abuts flat plate portions located on both sides of the core to form a closed magnetic path, and a winding attached to the central columnar portion of the T-shaped core.

Further, according to the present invention, in the above inductor, an inductor characterized in that a resin coating film is formed on an exterior surface of the inductor can be obtained.

Further, according to the present invention, in the inductor, the inductor having the insulating coating film on the central columnar portion of the T-shaped core can be obtained.

Further, according to the present invention, there is provided an inductor characterized in that the T-shaped core has an insulating bobbin in a central columnar portion.

Further, according to the present invention, in the inductor, the abutting portion between the T-shaped core and the core forming the closed magnetic path is bonded with an adhesive containing magnetic powder. .

Further, according to the present invention, there is provided an inductor characterized in that in the inductor, a resin is filled in a space formed by the core forming a closed magnetic circuit with the T-shaped core.

Further, according to the present invention, in the inductor, the resin filled in a space formed by the T-shaped core and a core forming a closed magnetic circuit is a resin mixed with magnetic powder. An inductor that operates is obtained.

[0013]

By using the T-shaped core, the core can be easily attached to the lead frame, and the winding on the central columnar portion can be performed without being disturbed by the legs on both sides like the E-shaped central leg. , Automation becomes easy. As the core material, various magnetic materials such as ferrite, sendust, and amorphous may be used. If necessary depending on the conductivity, the central columnar portion is covered with an insulating material or an insulating bobbin. By using, it is possible to secure the insulation of the inductor. In this case, since the bobbin itself does not need to have strength for maintaining its shape because the central columnar portion exists against the stress during winding, it is sufficient if the bobbin can maintain insulation, and the inductor can be miniaturized. .

Further, by using an adhesive agent mixed with magnetic powder at the abutting portion between the T-shaped core of the inductor and the core forming the closed magnetic path, the void portion of the abutting portion is filled with the magnetic material, and the magnetic circuit is further improved. Since it is formed reliably, it has high reliability as an inductor.

In addition, the space formed by the T-shaped core of the inductor and the core forming the closed magnetic circuit is filled with a resin mixed with magnetic powder as required, so that the winding is fixed and the core is fixed. The magnetic path cross-sectional area can be increased when magnetic powder is mixed. Therefore, since the current capacity of the inductor can be increased, the size of the inductor can be reduced.

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a front view showing an inductor of the present invention. FIG. 2 is an exploded perspective view showing a main part of the inductor of the present invention. As shown in FIGS. 1 and 2, the T-shaped core 1 is composed of a flat plate portion 1a and a central columnar portion 1b formed orthogonal to the flat plate portion 1a. Central columnar portion 1b of the T-shaped core 1
A U-shaped core 2 is arranged as a core that abuts on the front end surface of the and the flat plate portions 1a on both sides thereof to form a closed magnetic path. T
The winding 3 is attached to the central columnar portion 1b of the mold core 1.

The winding 3 can be directly wound and attached to the central columnar portion 1b of the T-shaped core 1 before the T-shaped core 1 and the core 2 forming the closed magnetic circuit are combined. The winding 3 can be directly applied to the central columnar portion 1b of the T-shaped core 1 by using either a flyer winding machine or a spindle winding machine.

FIG. 3 shows a T-shaped core 1 having a central columnar portion 1b coated with an insulating coating film 4. FIG. 4 shows a T-shaped core 1 having a central columnar portion 1b to which an insulating bobbin 5 is attached.
An insulating coating film 4 or an insulating bobbin 5 is used as necessary to improve the insulating property of the winding 3. Insulation coating film 4
Can be performed by applying an insulating resin such as an epoxy resin or spraying an insulating paint. The insulating bobbin 5 may be a thin one having a high insulating property such as phenol resin or diallyl phthalate resin. It is understood that the winding 3 can be attached to these as in the case shown in FIGS. 1 and 2, and the insulating coating film 4 and the insulating bobbin 5 hardly increase the size.

5 to 11 are views showing an example of assembling the inductor of the present invention. In this example, a case where a U-shaped core 2 is used as a core forming a closed magnetic circuit with the T-shaped core 1 will be described.

As shown in FIG. 5, the T-shaped core 1 is arranged on the terminal portion 7 of the lead frame 6 so that the flat plate portion 1a is straddled and fixed with a UV adhesive or the like. The winding 3 is wound around the central columnar portion 1b of the mold core 1 and both ends thereof are welded or soldered to the terminal portions 7 of the lead frame 6.

Next, as shown in FIG. 7, the U-shaped core 2 is covered on the T-shaped core 1 and the joint portion is fixed with an adhesive 8 as shown in FIGS. 8 and 9. Here, as the adhesive agent 8, an adhesive agent in which magnetic powder is mixed in epoxy resin, silicon resin or the like is used, so that the void portion of the contact portion between the T-shaped core 1 and the core 2 forming the closed magnetic path is made of a magnetic material. Since the magnetic circuit is more reliably filled with the magnetic field, the inductor can be made highly reliable.

Next, as shown in FIGS. 8 and 9, resin 9 is filled in the space formed by the T-shaped core 1 and the U-shaped core 2 forming the closed magnetic path. When resin such as epoxy resin or silicon resin mixed with magnetic powder is used as the resin 9 filled in the space formed by the T-shaped core 1 and the U-shaped core 2 forming the closed magnetic path, the winding 3 is By fixing the core and the core, the insulating property can be improved, and when magnetic powder is mixed, the cross-sectional area of the magnetic path can be increased. Therefore, since the current capacity of the inductor can be increased, the size of the inductor can be reduced.

Thereafter, as shown in FIG. 10, the T-shaped core 1
And forming a resin coating film 10 of epoxy resin or the like so as to wrap a part of the U-shaped core 2 and the terminal portion 7 of the lead frame 6, and separating the terminal portion 7 of the lead frame 6 from the lead frame 6 and bending. Thus, a chip-shaped inductor as shown in FIG. 11 is formed.

12 to 14 show another embodiment of the T-shaped core 1 and the core 2 forming a closed magnetic circuit. The core 11 shown in FIG. 12 has a box shape. With such a shape, the magnetism is completely shielded, so that it is possible to obtain an inductor having high characteristics with less leakage magnetic flux.

The core 12 shown in FIG. 13 is a box-shaped core with a part cut away. In this case, the magnetic shielding property is inferior to that of FIG. 12, but the workability of resin filling is improved.

The core shown in FIG. 14 is a box-shaped core having grooves on its side surfaces. In this case, it is possible to take out the winding terminals separately, and it is possible to obtain a highly reliable inductor with good workability of resin filling.

[0028]

Since the inductor of the present invention is a closed magnetic circuit type inductor having a winding as a conductor, it has high reliability and is not limited in size by a bobbin, so that it can be miniaturized to 5 mm square or less. It is also suitable for mass production because the winding can be performed while the T-shaped core is fixed on the lead frame and the winding can be easily automated and the core can be easily handled.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a main part of one embodiment of the present invention.

FIG. 3 is a front cross-sectional view for explaining an example in which an insulating coating film is applied to the T-shaped core of the present invention.

FIG. 4 is a front sectional view for explaining an example in which an insulating bobbin is attached to the T-shaped core of the present invention.

FIG. 5 is a perspective view for explaining an example of assembling the inductor of the present invention.

FIG. 6 is a perspective view for explaining an example of assembling the inductor of the present invention.

FIG. 7 is a perspective view for explaining an example of assembling the inductor of the present invention.

FIG. 8 is a perspective view for explaining one example of assembling the inductor of the present invention.

9 is a cross-sectional view taken along the line AA of the inductor of FIG.

FIG. 10 is a perspective view for explaining an example of assembling the inductor of the present invention.

FIG. 11 is a perspective view for explaining one example of assembling the inductor of the present invention.

FIG. 12 is a perspective view showing another example of a core forming a closed magnetic circuit with the T-shaped core 1 of the present invention.

FIG. 13 is a perspective view showing still another example of a core forming a closed magnetic circuit with the T-shaped core 1 of the present invention.

FIG. 14 is a perspective view showing still another example of a core forming a closed magnetic circuit with the T-shaped core 1 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 T-type core 1a Flat plate part 1b Central columnar part 2,11,12,13 Core 3 Winding 4 Insulation coating film 5 Bobbin 8 Adhesive 9 Resin 10 Resin coating film

Claims (7)

[Claims] 1. A T-shaped core having a flat plate portion and a central columnar portion formed orthogonal to the flat plate portion, a tip surface of the central columnar portion of the T-shaped core, and flat plate portions positioned on both sides thereof. An inductor, comprising: a core that is in contact with the core to form a closed magnetic path; and a winding attached to a central columnar portion of the T-shaped core. 2. The inductor according to claim 1, wherein
An inductor having a resin coating film formed on an exterior surface of the inductor. 3. The inductor according to claim 1, wherein the central columnar portion of the T-shaped core has an insulating coating film. 4. The inductor according to claim 1, wherein the central columnar portion of the T-shaped core has an insulating bobbin. 5. The inductor according to claim 1, 2, 3 or 4, wherein the contact portion between the T-shaped core and the core forming the closed magnetic circuit is bonded with an adhesive containing magnetic powder. And inductor. 6. The inductor according to claim 1, 2, 3, 4 or 5, wherein resin is filled in a space formed by the T-shaped core and a core forming a closed magnetic circuit. . 7. The inductor according to claim 6, wherein:
An inductor characterized in that the resin filled in a space formed by the core forming a closed magnetic circuit with the T-shaped core is a resin mixed with magnetic powder.