JPH05343238A - Micro magnetic core and wire-wound chip transformer - Google Patents

Abstract

PURPOSE:To obtain a stable inductance by making easy the manufacture of a wire-wound chip transformer. CONSTITUTION:A coil chip transformer is provided with a first insulating magnetic core 11 which has U shape and a second flat magnetic core 12. On the first magnetic core, the edge of a flange 11b is made flat. The first magnetic core is wound directly with a coil 13 and the second magnetic core is mounted and fixed on the edge surface of the flange 11b. The end of the coil is connected to terminals 17a to 17d. In this way, a coil chip transformer is structured. A micro magnetic core consisting of the first magnetic core 11 and the second magnetic core 12 is simple in shape and easy to manufacture. In addition, the first magnetic core 11 and the second magnetic core 12 can be easily adhered and bonded each other. Therefore, inductance can be stabilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micro magnetic core and a wire-wound chip transformer, and more particularly to a magnetic core shape of the micro magnetic core suitable for high-density mounting and an inductor structure of the chip transformer.

[0002]

2. Description of the Related Art In general, a so-called micro magnetic core is used in a wire wound type chip transformer used in an electronic circuit or the like.
Conventionally, a drum-shaped magnetic core has been used as a micro magnetic core.

Referring to FIG. 5, a drum-shaped magnetic core 51 shown in the drawing is shown.
Has a columnar winding portion 51a and flange portions 51b formed at both ends of the winding portion 51a, and the winding portion 51a is provided with a winding 52. A pair of electrode terminals 53 is attached to the outer surface of each flange 51b. Then, the ends of the windings 52 are attached to the electrode terminals 53 as shown in the drawing to form an open magnetic circuit to form a winding type chip transformer.

As another example of the winding type chip transformer, as shown in FIG. 6 (a), the drum-shaped magnetic core 51 described above is provided with electrode terminals 53 and windings 52 (in FIG. 6 (a), windings and electrodes are provided). Terminals are omitted), and then FIG. 6 (b)
There is a hollow magnetic core 54 having a closed magnetic circuit structure in which the drum-shaped magnetic core 51 is inserted and fitted.

[0005]

By the way, in the conventional winding type chip transformer, when forming the drum-shaped magnetic core, it is necessary to cut the round bar to form the drum-shaped magnetic core, which is troublesome. Therefore, not only the processing cost is high and the productivity is inferior, but it is difficult to reduce the size in consideration of the cutting strength.

As described above, it is difficult to reduce the size of the conventional drum-shaped magnetic core. Therefore, 160 specified in EIAJ is required.
There is a problem that it cannot be processed into 8 sizes or the like.

Furthermore, in a wire wound type chip transformer having an open magnetic circuit configuration, the effective magnetic permeability is lowered due to the open magnetic circuit configuration, and in order to obtain a desired exciting inductance, the number of windings is increased and the DC resistance value is increased. Need to be increased. In addition, in a wire wound type chip transformer with an open magnetic circuit, magnetic flux scatters (leaks) at the opening of the magnetic circuit, which not only lowers the magnetic coupling coefficient between the winding circuits but is also placed around it. The electronic circuit parts and the like are adversely affected such as malfunction.

The problem in the wire wound type chip transformer having the open magnetic circuit is solved by using the wire wound type chip transformer having the closed magnetic circuit shown in FIG.
The winding-type chip transformer shown in (1) also uses the drum-shaped magnetic core, and also needs to use the hollow magnetic core. If this point is taken into consideration, the manufacturing cost increases and the economical efficiency deteriorates. In addition, in a wound-type chip transformer having a closed magnetic circuit, so-called phase bonding is performed between the hollow magnetic core and the flange of the drum-shaped magnetic core. It is difficult to secure dimensional accuracy, and as a result, it is extremely difficult to obtain stable inductance and coupling coefficient.

An object of the present invention is to provide a micro magnetic core which is easy to process and inexpensive.

Another object of the present invention is to provide a wire-wound chip transformer capable of obtaining a stable inductance.

[0011]

According to the present invention, a flat plate-shaped magnetic body extending in a predetermined direction and a magnetic material, which is predetermined from a surface of the magnetic body in a direction perpendicular to the predetermined direction, are provided. A magnetic core having a pair of flange portions projecting at intervals, the magnetic core is electrically insulating, a winding portion is defined by the magnetic body and the collar portion, and one surface of the collar portion is planar. A micro magnetic core is obtained which is characterized by being molded into. Then, by using this micro magnetic core, the magnetic body is directly wound in the winding portion, a plurality of electrode terminals are provided on the micro magnetic core, and the winding ends are connected to these electrode terminals to thereby form a winding type chip transformer. Composed.

Further, according to the present invention, a flat plate-shaped magnetic body extending in a predetermined direction and one surface of the magnetic body made of a magnetic material are provided at a predetermined interval in a direction perpendicular to the predetermined direction. It has a first magnetic core having a pair of projecting flanges, and a second magnetic core formed of a magnetic material and formed into a flat plate shape, the first magnetic core being electrically insulating, and the magnetic body. And the flange portion define a winding portion, one surface of the flange portion is formed into a flat shape, and the second magnetic core is disposed on one surface of the flange portion. Is obtained. Then, by using this micro magnetic core, the magnetic body is directly wound in the winding portion, the second magnetic core is abutted and fixed to the first magnetic core on one surface of the flange portion, and the plurality of electrode terminals are attached to the micro magnetic core. And the winding ends are connected to these electrode terminals to form a winding type chip transformer.

[0013]

In the present invention, since the magnetic core is composed of the flat plate-shaped magnetic body and the pair of flange portions projecting from one surface of the magnetic body, that is, the magnetic core is formed in a substantially U-shape, The magnetic core (first magnetic core) can be created very easily and accurately. Further, when the flat plate-shaped second magnetic core is brought into contact with the flange portion to form a closed magnetic circuit by forming the projecting end of the flange portion into a planar shape, the first magnetic core and the second magnetic core are brought into close contact with each other with high accuracy. As a result, a stable inductance can be obtained.

[0014]

EXAMPLES The present invention will be described below with reference to examples.

First, a first embodiment of the micro magnetic core according to the present invention will be described with reference to FIG.

The illustrated micro magnetic core is a U-shaped magnetic core 11.
And a flat magnetic core 12. The magnetic core 11 includes a flat plate-shaped bottom portion 11a and collar portions 11b integrally formed at both ends of the bottom portion 11a, and an upper surface of the collar portion 11b has a magnetic core 12a.
Used as a joint surface with. The magnetic core 11 has an electrical insulation property, and a magnet wire (not shown) is directly wound around the bottom portion 11a of the magnetic core 11. At this time, the winding space of the magnet wire is defined by the collar portion 11b. Further, the flange portion 11b increases the induction coefficient of the open magnetic circuit magnetic core (which is about the same as the drum core).

As described above, the magnetic core 12 is in contact with the joint surface of the collar portion 11b. Since this joint surface is flat and the magnetic core 12 is flat, the magnetic core 12 can be brought into close contact with the collar portion 11b.

As described above, the magnetic core 11 alone has an open magnetic circuit, and the magnetic core 11 and the magnetic core 12 are combined to easily form a closed magnetic circuit. That is, it is possible to obtain a micro magnetic core having a high coupling coefficient simply by abutting and adhering the magnetic core 12 to the collar portion 11b.

When forming the magnetic cores 11 and 12, the powder such as Ni ferrite and the binding resin are kneaded to obtain a kneaded body, and the magnetic sheet is formed by the doctor blade method or the extrusion molding method. Then, this magnetic material sheet is processed by a method such as a punch forming method to form the magnetic core 11
And 12 are formed. In this way, each magnetic core can be manufactured quickly and in large quantities.

When forming the magnetic cores 11 and 12, the above kneaded body may be directly continuously formed into a U-shape or a flat plate shape by an extrusion molding method. Alternatively, the magnetic cores 11 and 12 may be obtained by cutting.

By forming the magnetic cores 11 and 12 in this manner, the magnetic core can be formed very easily, and the machining cost is reduced because it is not necessary to perform the cutting work unlike the conventional drum-shaped magnetic core. Not only can it be done, but it can also be made smaller.

In addition, it is possible to simply join the magnetic cores 11 and 12 by simply bringing them into contact with each other without the need for complicated dimension matching between the drum-shaped magnetic core and the hollow magnetic core as in the conventional case. As a result, the induction coefficient can be easily stabilized.

Although the U-shaped magnetic core is used as the magnetic core 11 in the above-described embodiment, the magnetic core 11 shown in FIG.
A magnetic core having a shape shown in (b) may be used. Each of the magnetic cores shown in FIGS. 2A and 2B is provided with a flat plate-shaped bottom portion 11a and a collar portion 11b on which windings are applied. As described above, the magnetic core 11 only needs to have the flat plate-shaped bottom portion 11a and the brim portion 11b having the joint surface, and can be deformed into various shapes.

Now, with reference to FIG. 3, a winding type chip transformer having an open magnetic circuit configuration using the micro magnetic core (U-shaped magnetic core) shown in FIG. 1 will be described.

Referring to FIG. 3A, the magnetic core 11 is electrically insulating as described above, and the two windings (magnet wires) 13 are directly wound around the bottom 11a thereof. As shown in the figure, the collar portion 11b has electrode terminals 14a, 14b, 1
4c and 14d are attached. The electrode terminal 14a includes a connecting portion 15a arranged along the side surface of the collar portion 11a and a terminal body 16a connected to the connecting portion 15a and extending outward from the end face of the collar portion. Similarly, the electrode terminal 14b,
14c and 14d are connection parts 15b, 15c,
And 15d and terminal bodies 16b, 16c, and 16d.

Each end of the winding 13 has a connecting portion 14
a, 14b, 14c, and 14d, and as a result, the transformer of the equivalent circuit shown in FIG. 3B is formed.

As described above, by using the U-shaped magnetic core as the micro magnetic core, it is possible to easily and inexpensively construct the winding type chip transformer having the open magnetic circuit configuration.

Next, with reference to FIG. 4, a winding type chip transformer having a closed magnetic circuit structure using the micro magnetic core shown in FIG. 1 will be described.

Referring to FIG. 4 (a), the magnetic core 11 is electrically insulating, and two windings (magnet wires) 13 are directly wound around the bottom 11a thereof. After winding the winding 13, the magnetic core 12 is placed on the contact surface of the collar portion 11b.
The magnetic cores 11 and 12 are connected to the electrode terminals 17a, 17b,
It is clamped by 17c and 17d.

The electrode terminal 17a has a connecting portion 18a arranged along the side surface of the collar portion 11a. This connection 1
A claw portion 19a is formed at one end (upper end) of 8a, and a bent portion 20a is formed at the other end (lower end), and the magnetic cores 11 and 12 are sandwiched between the bent portion 20a and the claw portion 19a. .. A terminal body 21a extending outward from the end surface of the collar portion is connected to the bent portion 20a. Similarly, the electrode terminals 17b, 17c, and 17d are respectively connected to the connection portions 18b, 18c, and 18d and the terminal body 21.
b, 21c, and 21d, the magnetic core 1 is provided by the claw portion 19b and the bent portion 20b, the claw portion 19c and the bent portion 20c, and the claw portion 19d and the bent portion 20d, respectively.
1 and 12 are sandwiched. That is, the electrode terminal 17
The magnetic cores 11 and 12 are held and fixed by a, 17b, 17c, and 17d.

Each end of the winding 13 has a connecting portion 18
a, 18b, 18c, and 18d, and as a result, the transformer of the equivalent circuit shown in FIG. 4B is formed.

As described above, by using the U-shaped magnetic core and the plate-shaped magnetic core as the micro magnetic core, it is possible to easily and inexpensively construct the winding type chip transformer having the closed magnetic circuit. Moreover, the use of the above-mentioned micro magnetic core facilitates positioning when forming a closed magnetic circuit, and since the U-shaped magnetic core and the flat magnetic core are easily brought into close contact with each other, the inductance is stabilized and the Q characteristic is also stabilized.

In the wound-type chip transformer having the closed magnetic circuit, the electrode terminals are used to hold and fix the U-shaped magnetic core and the flat plate-shaped magnetic core. However, the U-shaped magnetic core and the flat-shaped magnetic core are directly bonded by an adhesive. Alternatively, the wire-wound chip transformer having a closed magnetic circuit can be easily and inexpensively manufactured.

[0034]

As described above, in the present invention, the magnetic core is composed of the flat plate-shaped magnetic body and the pair of flange portions projecting from one surface of the magnetic body, that is, the magnetic core is substantially U-shaped. Since it is molded into, the magnetic core (first magnetic core) can be formed extremely easily and accurately. further,
By making the projecting end of the collar portion flat, the flat second
The first magnetic core and the second magnetic core can be brought into close contact with each other with high accuracy when the magnetic core of the above is brought into contact with the flange portion to form a closed magnetic circuit, and as a result, high inductance can be obtained with few windings and the winding The magnetic coupling coefficient between them can be increased. Therefore, there is an effect that it is possible to form a small-sized and high-performance wire-wound chip transformer.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing another example of a first magnetic core (substantially U-shaped magnetic core) in the micro magnetic core shown in FIG.

FIG. 3A is a perspective view showing an embodiment of a wound-type chip transformer having an open magnetic circuit configuration using a micro magnetic core according to the present invention, and FIG. 3B is a diagram showing an equivalent circuit thereof.

FIG. 4A is a perspective view showing an embodiment of a wound-type chip transformer having a closed magnetic circuit configuration using a micro magnetic core according to the present invention, and FIG. 4B is a diagram showing an equivalent circuit thereof.

FIG. 5 is a perspective view showing an example of a conventional wire-wound chip transformer having an open magnetic circuit configuration.

FIG. 6 is a perspective view for explaining a conventional micro magnetic core having a closed magnetic circuit configuration.

[Explanation of symbols]

 11, 12 Magnetic core 11a Bottom part 11b Collar part 13 Winding (magnet wire) 14a, 14b, 14c, 14d Electrode terminal 17a, 17b, 17c, 17d Electrode terminal

Claims (4)

[Claims] 1. A flat plate-shaped magnetic body extending in a predetermined direction,
A magnetic core made of a magnetic material, the magnetic core having a pair of flanges protruding from the one surface of the magnetic body at a predetermined interval in a direction perpendicular to the predetermined direction, and the magnetic core is electrically insulating; A micro magnetic core, wherein a winding portion is defined by a magnetic body and the collar portion, and one surface of the collar portion is formed into a flat shape. 2. The micro magnetic core according to claim 1, wherein the magnetic body is directly wound in the winding portion, and the micro magnetic core is provided with a plurality of electrode terminals. A wire-wound chip transformer, wherein the winding ends are connected to the electrode terminals. 3. A flat plate-shaped magnetic body extending in a predetermined direction,
A first magnetic core having a pair of flanges formed of a magnetic material and protruding from one surface of the magnetic body at a predetermined interval in a direction perpendicular to the predetermined direction; A molded second magnetic core, the first magnetic core is electrically insulative, a winding portion is defined by the magnetic body and the flange portion, and one surface of the flange portion is formed into a planar shape. The micro magnetic core, wherein the second magnetic core is disposed on one surface of the collar portion. 4. The micro magnetic core according to claim 3 is used, and the magnetic body is directly wound in the winding portion, and the second magnetic core is provided with respect to the first magnetic core. A winding-type chip transformer characterized in that it is abutted and fixed on one surface of the flange portion, a plurality of electrode terminals are provided on the micro magnetic core, and the winding ends are connected to the electrode terminals.