JP3234216B2 - Cored coil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial applications]

The present invention relates to a cored coil having a core obtained by combining core elements.

[0002]

[Prior art]

Conventionally, as shown in FIGS. 6 and 7, a core 1 is formed by combining a first core body 1a having a substantially E-shaped cross section and a second core body 1b having a substantially I-shaped cross section. , Core 2 with winding 2
Is provided with a cored coil. The cores 1 are combined so as to form a closed magnetic path, and the windings 2 are formed as a spiral coil pattern 4 on a printed wiring board 3. The printed wiring board 3 is a double-sided board, in which coil patterns 4 are formed on both front and back surfaces.
Is electrically connected through The printed wiring board 3 has an opening 6 through which the leg of the core body 1a is inserted.

[0003]

[Problems to be solved by the invention]

By the way, the core 1 forms a closed magnetic circuit when the two core element bodies 1a and 1b come into contact with each other. The element bodies 1a and 1b cannot be completely brought into close contact, and a slight gap is formed on the contact surface. When such a gap exists, there arises a problem that the magnetic resistance increases and the inductance decreases.

[0004] The effect of such a gap will be described using a simple model. That is, assuming that the core 1 is formed in a toroidal shape as shown in FIG. 8, the average length of the magnetic path is 1, the width of one gap g is lg, the magnetic permeability of the material of the core 1 is μ, air Is the magnetic permeability of μ ₁ (= 1) and the apparent magnetic permeability of the core 1 is μ ′, the following relational expression is established.

(1 + 2lg) / μ ′ = 1 / μ + 2lg / μ ₀ Therefore, the apparent magnetic permeability μ ′ of the core 1 is μ ′ = (l + 2lg) / μ / (l + 2lg · μ). Here, since l≫lg, the following equation is established.

Μ ′ ≒ l · μ / (l + 2lg · μ) Assuming that the magnetic permeability μ of the core 1 is 1000, the average length l of the magnetic path is 10 mm, and the width lg of the gap g is 5 μm, Since the apparent magnetic permeability μ ′ becomes 500, the magnetic permeability becomes half by the existence of the gap g. Since the magnetic permeability decreases when the gap g exists as described above,
This causes a problem that the inductance is reduced.

The cored coil having the configuration shown in FIGS. 6 and 7 has a printed wiring board 3 interposed between an E-shaped core body 1a and an I-shaped core body 1b. Therefore, the dimension in the thickness direction of the printed wiring board 3 is relatively large.

An object of the present invention is to solve the above problems.
It is an object of the present invention to provide a cored coil having a small thickness while suppressing a decrease in inductance while winding a winding around a core obtained by combining a plurality of core elements.

[0009]

[Means for Solving the Problems]

In the present invention, in order to achieve the above object, a pair of core elements made of a flat magnetic body and a pair of opposed core elements, and a conductive material printed on a surface of one core element facing the other core element. Or a coil pattern formed by plating, a magnetic compound formed by combining a magnetic material powder and a polymer material, joining the opposing surfaces of both core elements, and a magnetic compound disposed at the center and outside of the coil pattern. The pair of core elements forms a closed magnetic circuit via these magnetic compounds.

[0010]

[Action]

According to the above configuration, since the magnetic compound is filled in the joint of the core element, even if there are irregularities on the surface of the core element, the gap formed in the joint of the core element is formed by the magnetic compound. It is buried, and the decrease in inductance due to the existence of the gap can be suppressed. Further, the core element is flat and opposed to each other, and a coil pattern is formed by printing or plating a conductive material on a surface of one core element facing the other core element, and a central portion of the coil pattern is formed. Further, since the magnetic compound is arranged on the outside and the opposing surfaces of both core element bodies are joined by the magnetic compound, it is possible to provide a cored coil having a small thickness.

(Basic Configuration) As shown in FIG. 1 and FIG. 2, the basic configuration is the same as the conventional configuration shown in FIG. 6 and FIG. 7, and at the junction of the core element bodies 1a and 1b. The only difference is that the magnetic compound 7 is filled between the core bodies 1a and 1b. The magnetic compound 7 is a composite of magnetic powder and a polymer material, and a thermosetting resin, an ultraviolet-curing resin, or the like is used as the polymer material. Therefore, when the magnetic compound 7 is filled between the core bodies 1a and 1b, the magnetic compound 7 is in a liquid state and has fluidity, and the unevenness of the surface of the core bodies 1a and 1b made of ferrite is reduced. It can be filled. Further, by curing the polymer material, both core bodies 1a and 1b can be bonded.

When such a magnetic compound 7 is used, assuming that the magnetic compound 7 is filled in the gap g in the model shown in FIG. 8 and the magnetic compound 7 has a magnetic permeability of μp, the following equation is established. Will be.

(1 + 2lg) / μ ′ = 1 / μ + 2lg / μp Therefore, the apparent magnetic permeability μ ′ of the core 1 is μ ′ = (1 + 2lg) μ · μp / (l · μp + 2lg · μ). Assuming that the magnetic permeability μp of the magnetic compound 7 is equal to the magnetic permeability of the material of the core 1, the apparent magnetic permeability of the core 1 is equal to the magnetic permeability of the material of the core 1. Here, the magnetic permeability μ of the material of the core 1 is 1000, the average length l of the magnetic path is 10 mm,
Assuming that the width lg of the gap g is 5 μm and the magnetic permeability of the magnetic compound 7 is 500, the apparent magnetic permeability μ ′ of the core 1 is 998 from the above equation, and the magnetic permeability hardly decreases. Become. Therefore, there is almost no decrease in inductance.

[0014]

Embodiment 1 (Embodiment 1) In this embodiment, the core elements 1a and 1b are joined using the magnetic compound 7 in the same manner as in the above-described basic configuration. As shown in the figure, both core elements 1
a, 1b are formed in a plate shape, and one of the core element bodies 1a
, A spiral coil pattern 4 is formed by printing or plating a conductive material on the surface facing the other core element 1b, and the coil pattern 4 is used as the winding 2. A magnetic compound 7 is filled at important points between the two core bodies 1a and 1b in consideration of the shape of the coil pattern 4, and the two core bodies 1a and 1b form a closed magnetic path via the magnetic compound 7. It has become. The other configuration is the same as the basic configuration, and the description is omitted.

Example 2 In this example, core elements 1a and 1b were formed in a flat plate shape as in Example 1, and a surface of core element 1a facing core element 1b was formed. Are formed as a pair of parallel linear coil patterns 4a and 4b. Each of the coil patterns 4a and 4b is formed by printing or plating a conductive material as in the first embodiment. A magnetic compound 7 is filled at a location between the core bodies 1a and 1b, and a closed magnetic path is formed via the magnetic compound 7. If the coil patterns 4a and 4b are formed as described above, one of the coil patterns 4a and 4b can be used as a transmission line transformer having a primary coil and the other a secondary coil. Other configurations and operations are the same as those of the basic configuration, and a description thereof will not be repeated.

[0016]

【The invention's effect】

As described above, the present invention forms a pair of opposing core elements made of a flat magnetic body, and forms or prints a conductive material on a surface of one of the core elements facing the other core element. And a magnetic compound that is formed by combining magnetic powder and a polymer material and that joins the opposing surfaces of both core element bodies and that is disposed at the center and outside of the coil pattern. Through the magnetic compound, the pair of core bodies form a closed magnetic circuit, and the magnetic compound is filled in the joint of the core bodies, so that there are irregularities on the surface of the core body. Also, there is an advantage that the gap formed at the junction of the core element is filled with the magnetic compound, so that a decrease in inductance due to the presence of the gap can be suppressed. Further, the core element is flat and opposed to each other, and a coil pattern is formed by printing or plating a conductive material on a surface of one core element facing the other core element,
Since the magnetic compound is arranged at the center and outside of the coil pattern and the opposing surfaces of the two core bodies are joined by the magnetic compound, it is possible to provide a cored coil having a small thickness dimension. is there. Furthermore, the coil pattern and the magnetic compound can be provided on the same surface of the core body, and there is an advantage that manufacturing is easy.

[Brief description of the drawings]

1 is a cross-sectional view showing a basic configuration, FIG. 2 is an exploded perspective view of the same, FIG. 3 is a cross-sectional view showing a first embodiment of the present invention, FIG. 4 is an exploded perspective view of the same, and FIG. FIG. 6 is an exploded perspective view showing a second embodiment of the present invention, FIG. 6 is a cross-sectional view showing a conventional example, FIG. 7 is an exploded perspective view of the same, and FIG. 1 core, 1a, 1b core body, 2 winding, 7
Magnetic compound.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Keiichi Mizuguchi 1048 Kazuma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Works, Ltd. 56) References JP-A-60-138904 (JP, A) JP-A-59-171315 (JP, U) JP-A-1-133814 (JP, U) JP-A-51-82953 (JP, U) 1937-19746 (JP, Y1)

Claims (1)

(57) [Claims] A coil formed by printing or plating a conductive material on a pair of opposed core elements made of a plate-shaped magnetic element and opposing surfaces of one core element and the other core element. A pattern, a magnetic powder and a polymer material are combined to form a magnetic compound that is formed by combining the opposing surfaces of both core elements and is disposed at the center and outside of the coil pattern. A core-containing coil, wherein the pair of core elements forms a closed magnetic circuit via the core.