JPH04323809A - Micro-magnetic core and coil type chip inductor - Google Patents

Abstract

PURPOSE:To obtain a micro-magnetic core and a coil type chip inductor element capable of corresponding to a microsize such as 1608 size or the like, holding stable inductance, and having an economical low cost. CONSTITUTION:A micro-magnetic core having a micro-size according to the present invention has a substantially U-shaped U-type chip 11. A winding type inductor can be obtained by making a coil on the U-type chip 11. The winding type inductor of the micro-size according to the present invention has a substantially U-shaped Utype chip 11, a substantially flat-shaped dash-type chip 12 which is respectively connected to a junction plane 13 of both ends of the U-type chip 11, and a coil wound on the U-type chip 11.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a micro-sized wound chip inductor used in electronic circuits that require miniaturization through high-density packaging, and in particular, the present invention relates to a micro-sized wound chip inductor that is used in electronic circuits that require miniaturization through high-density packaging. This invention relates to a wound chip inductor element in which a sintered body is wound. In the present invention, micro size is 5 mm in length and 5 mm in width.
It refers to something smaller than mm.

0002

2. Description of the Related Art Conventionally, this type of micro-sized wound chip inductor element has a drum-shaped magnetic core 51 made of a sintered body such as ferrite, as shown in FIG. A winding wire 52 is provided between a pair of collar portions 51a, and a winding end connection portion 53 and an electrode terminal 54 are connected to each of the collar portions 51a.

[0003] By the way, in order to manufacture such a chip of a drum-shaped magnetic core, a cutting process is required in which a long and thin round bar is cut into a chip of a desired length. Since the cost of this cutting process increases, the productivity of the chips is poor. In addition, since the chip requires a certain degree of cutting strength, there is a limit to miniaturization of the chip size, and the product size of the wound chip inductor element is the 3225 size (length 3 .2m
m width 2.5mm) and 2520 size (length 2.5mm)
2.0 mm width), and the product size is 16 mm.
There is a fatal flaw in that it is extremely difficult to adapt to micro size such as 08 size. Moreover, in the case of such an open magnetic path configuration, the magnetic flux may diverge from the opening of the magnetic path, causing adverse effects such as malfunctions on surrounding electronic circuit components, and the effective magnetic permeability is low, making it difficult to achieve the desired inductance. It may not be possible to obtain the value of

For this reason, there is a wound chip inductor element having a closed magnetic circuit configuration. As this conventional example, FIG.
There is a configuration in which the hollow magnetic core 62 shown in (a) is fitted.

[0005]

However, in order to manufacture a wound chip inductor having such a closed magnetic circuit configuration, the manufacturing cost of the hollow magnetic core 61 is large, which hinders economic efficiency.

[0006] Also, the flange portion 61a of the drum-shaped magnetic core 61
A curved surface connection is formed between the hollow magnetic core 62 and the hollow magnetic core 62. Therefore, it is not possible to ensure high dimensional accuracy between the sintered bodies such as ferrite that form the magnetic core, and it becomes impossible to respond to micro-sizes such as 1608 size. There was a drawback that a micro magnetic core and a wound chip inductor could not be secured.

[0007] Therefore, the technical problem of the present invention is 1608
The object of the present invention is to obtain an economical micro magnetic core and wound chip inductor that can be adapted to micro sizes, maintain stable inductance, and the like.

[0008]

[Means for Solving the Problems] According to the present invention, there is obtained a micro-sized micro-magnetic core characterized by having a substantially U-shaped tip. Further, according to the present invention, in the wound type chip inductor using this micro magnetic core, a wound type chip inductor is obtained in which the U-shaped chip is wound. Furthermore,
According to the present invention, in a micro-sized wound chip inductor, a substantially U-shaped chip, a substantially flat-shaped chip joined to the joint surfaces at both ends of the U-shaped chip, and the U-shaped A wound chip inductor is obtained, which is characterized by having a winding wound around a chip.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A micro magnetic core and a wound chip inductor according to an embodiment of the present invention will be described below with reference to the drawings.

Referring to FIG. 1, a micro magnetic core according to an embodiment of the present invention has a substantially U-shaped chip 11 and a substantially flat-shaped chip 12. As a micro magnetic core,
There is a combination of a U-shaped chip 11 and a --shaped chip 12. First, a micro magnetic core consisting of only the U-shaped chip 11 will be explained, and later a micro magnetic core consisting of a combination of the U-shaped tip 11 and the --shaped tip 12 will be explained. The U-shaped chip 11 has an insulating property, and a magnet wire is wound around the bottom portion 14 of the U-shaped chip 11 . In this way, a wound chip inductor with an open magnetic path configuration is obtained. U-shaped tip 11
The curled collar portions 15 on the inner side surfaces at both ends act to increase the inductance value. The U-shaped chip 11 does not use a bobbin and winds the winding directly, so there is no insulation failure. Needless to say, the micro magnetic core of the present invention can be obtained by applying an insulating coating to the chip, even if the chip has a relatively low electrical resistance, such as Mn-based ferrite.

[0011] Furthermore, the U-shaped chip 11 having a wire wound thereon can be fitted with the --shaped chip 12 to form a closed magnetic circuit configuration. In the case of a wound chip inductor having a closed magnetic circuit configuration, the U-shaped chip 11 and the -shaped chip 12 can be opposed to each other, and the joint surface 13 of the U-shaped chip 11 can be joined to the -shaped chip 12 in a plane. Note that FIGS. 2(a) and 2(b) show other embodiments of the U-shaped chip 11.

[0012] When manufacturing such a micro magnetic core,
After forming a kneaded body of powder such as Ni ferrite and binding resin and forming a raw magnetic sheet by the doctor blade method or extrusion molding method, the magnetic cores of the chips described above are quickly and mass-produced by punching method. This has the effect of making it possible to produce

When the kneaded body is directly produced as a U-shaped magnetic core or a continuum of -shaped magnetic cores by means of extrusion molding, it can be cut into the above-mentioned chip cores, so that processing by the conventional cutting process of a drum-shaped magnetic core is not necessary. Costs can be reduced, and there are no restrictions on miniaturization due to the strength required during the cutting process. Moreover, when using the above-mentioned chip in a closed magnetic circuit configuration, the complicated size adjustment of the curved surface joint of the drum-shaped magnetic core in the conventional example is no longer necessary, and a chip for a smaller and cheaper wound chip inductor can be easily obtained. It will be done.

Referring to FIG. 3, a wound chip inductor according to an embodiment of the present invention, ie, a wound chip inductor using the above-mentioned chip, has a substantially U-shaped chip having a winding 33. It has 31. On the U-shaped side surfaces at both ends of the U-shaped chip 31, both ends of a winding 33 are joined to electrode terminals 32 via winding end joints 34.

Referring to FIG. 4, a wound type chip inductor according to another embodiment of the present invention has a generally flat plate-like structure that is bonded to bonding surfaces 13, 13 at both ends of the U-shaped chip 11 of the wound type chip inductor of FIG. It has a horn-shaped tip 12.

In the wound type chip inductor according to another embodiment of the present invention, the U-shaped chip 11 and the -shaped chip 12 are held together by the electrode terminals 32, but it can also be done with an adhesive. It goes without saying that it can be done.

FIG. 5(a) shows a B-NI characteristic curve diagram of the wound chip inductor according to another embodiment of FIG.
Case a when there is no gap between and b when there is a gap between
A comparison is being made with. When it is desired to pass a large current through the wound chip inductor, a gap of about a few tenths of a micron is provided by providing a polishing step for polishing the sintered chip after forming the sintered chip.

FIG. 5(b) shows an L-NI characteristic curve diagram of the wound chip inductor according to another embodiment of FIG. It will be understood that by providing a gap between the joint surfaces 13, 13 of the chip 11 and the --shaped chip 12, a decrease in inductance can be prevented.

[0019]

Effects of the Invention According to the present invention, 3225 size and 2
Not only the 520 size but also the micro size such as the 1608 size can be applied, and there is an effect that a stable inductance can be maintained and an economical and low cost micro magnetic core and wound chip inductor element can be obtained.

[Brief explanation of drawings]

FIG. 1 is an external view of a micro magnetic core according to an embodiment of the present invention.

FIG. 2 (a) and (b) are external views of a micro magnetic core according to another embodiment of the present invention.

FIG. 3 is an external view of a wound chip inductor according to an embodiment of the present invention.

FIG. 4 is an external view of a wound chip inductor according to another embodiment of the present invention.

5(a) is a B-NI characteristic curve diagram of the wound chip inductor according to another embodiment of FIG. 4. FIG. FIG. 5(b) is an L-NI characteristic curve diagram of the wound wire chip inductor according to another embodiment of FIG. 4.

FIG. 6 is an external view of a conventional wound chip inductor with an open magnetic path configuration.

FIG. 7 is an external view of a conventional wound chip inductor with a closed magnetic circuit configuration.

[Explanation of symbols]

11 substantially U-shaped U-shaped chip 12 substantially flat-shaped chip 13 joint surfaces 15 at both ends of U-shaped chip 11 winding collar portion 51 drum-shaped magnetic core 51a collar portion 52 winding 53 winding terminal connection portion 54 electrode terminal 61 Drum-shaped magnetic core 61a collar part

Claims (3)

[Claims] 1. A micro-sized micro-magnetic core characterized by having a substantially U-shaped tip. 2. A wound chip inductor using a micro magnetic core according to claim 1, wherein the U-shaped chip is wound. 3. A micro-sized wound chip inductor, comprising: a substantially U-shaped chip; a substantially flat-shaped chip bonded to bonding surfaces at both ends of the U-shaped chip; and the U-shaped chip. A wire-wound chip inductor comprising a winding wire wound around the wire.