JP3383922B2 - Winding chip transformer - Google Patents

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, the drum-shaped magnetic core 51 shown in the figure is shown.
Is provided with a columnar winding portion 51a and flange portions 51b formed at both ends of the winding portion 51a, and a winding wire 52 is provided on the winding portion 51a. 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.

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

[0005]

By the way, in the conventional wire-wound chip transformer, when the drum-shaped magnetic core is formed, it is necessary to cut the round bar into 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.

Further, 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 reduces 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 a drum-shaped magnetic core, and also needs to use a hollow magnetic core. If this point is taken into consideration, the manufacturing cost will increase and the economy will be poor. In addition, since the so-called phase bonding is performed between the hollow core and the flange of the drum-shaped core in the winding type chip transformer having the closed magnetic circuit configuration, for example, when a sintered body such as ferrite is used, the surface bonding in 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 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 in a direction perpendicular to the predetermined direction from one surface of the magnetic body, 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 flange portion, and one surface of the flange portion is planar. On the winding part
And the winding directly wound on the magnetic body, and the side of the collar portion.
A connection part arranged along a surface and connected to the ends of the winding
And the connecting portion on the surface opposite to the one surface of the magnetic body.
An electrode terminal composed of a terminal body connected to
A wire-wound chip transformer characterized by the above is obtained.

In the above wire wound type chip transformer, the magnetic
Another magnetic core made of a flexible material and formed in a flat plate shape is
It is placed on one side of the unit. Also, the upper end of the connecting portion and
The lower end is formed with a claw portion and a bent portion, respectively.
The pole terminal is connected to the connecting portion through the bent portion.
The micro by the claw portion and the bent portion.
The magnetic core and the other magnetic core are sandwiched.

[0013]

In the present invention, since the magnetic core is composed of the flat plate-shaped magnetic body and the pair of flanges 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 flat 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.

Referring to FIG. 1, first, a first embodiment of the micro magnetic core according to the present invention will be described.

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 flange portions 11b integrally formed at both ends of the bottom portion 11a, and the top surface of the flange portion 11b is the magnetic core 12.
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 enhances the induction coefficient as the open magnetic circuit magnetic core (the same as that of the drum-shaped 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 constitutes 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 body sheet is formed by the doctor blade method or the extrusion molding method. Then, this magnetic 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.

Further, 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 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 a U-shaped magnetic core is used as the magnetic core 11 in the above-described embodiment, the magnetic core 11 shown in FIG.
You may use the magnetic core of the shape shown to (b). 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 provided. 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, as described above, the magnetic core 11 is electrically insulative, and two windings (magnet wires) 13 are directly wound around the bottom 11a thereof. As shown in the drawing, 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 wire wound 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. 4A, the magnetic core 11 is electrically insulative, 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 flange 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, by using the above-mentioned micro magnetic core, positioning when forming a closed magnetic circuit is easy, and since the U-shaped magnetic core and the flat magnetic core are easily brought into close contact with each other, the inductance and the Q characteristic are stabilized.

In the wound-type chip transformer having a 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 precision when the magnetic core of the above is brought into contact with the collar to form a closed magnetic circuit, and as a result, high inductance can be obtained with a small number of windings and The magnetic coupling coefficient between them can be increased. Therefore, there is an effect that a small-sized and high-performance wire-wound chip transformer can be formed.

[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 wire wound chip transformer having an open magnetic circuit using a micro magnetic core according to the present invention, and FIG. 3B is a view 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 structure using a micro magnetic core according to the present invention, and FIG. 4B is a view 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 11b Tsuba 13 windings (magnet wire) 14a, 14b, 14c, 14d electrode terminals 17a, 17b, 17c, 17d Electrode terminals

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Claims (3)

(57) [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 winding part is defined by a magnetic body and the flange part, and one surface of the flange part is formed in a flat shape .
Magnetic core and winding wound directly on the magnetic body in the winding section
And the ends of the windings are connected along the side surface of the collar
Side of the connecting portion and the one surface of the magnetic body
An electrode terminal comprising a terminal body connected to the connection part by
And a wire-wound chip transformer. 2. A flat member made of a magnetic material, etc.
The magnetic core of is placed on one surface of the collar portion.
The wire wound type chip transformer according to claim 1. 3. The upper end and the lower end of the connecting portion are provided with claws, respectively.
Part and a bent part are formed, and the electrode terminal is
The claw portion is connected to the connecting portion through the bent portion.
And the bent portion, the micro magnetic core and the
The magnetic core according to claim 2, wherein another magnetic core is sandwiched.
Wire wound chip transformer.