JPH0124899Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chip-shaped high frequency coil whose electrodes are surface-connected to a circuit pattern on a substrate.

In recent years, with the miniaturization of electronic components, so-called chip-shaped high-frequency coils, in which electrodes are directly surface-connected to circuit patterns on synthetic resin or ceramic substrates, are being used, but their size is now 4 mm on a side.
It has a very small shape that can fit into a 3mm cube. The electrodes are formed by adhering a linear or plate-shaped metal piece to the flange of the core, or by printing or vapor depositing silver or the like. Parts other than the electrodes may be coated with synthetic resin to protect the entire part.

However, since this type of high-frequency coil does not have a metal case or core surrounding its windings, if it is connected to a circuit pattern on a board with other circuit components in a high packaging density, it may cause damage to other circuit components. The characteristics tend to become unstable due to the influence, and its own leakage magnetic flux tends to adversely affect surrounding circuit components. It is easy to mechanically fix the case to the base of a general high-frequency coil in which a core with a winding wire is placed on a synthetic resin base, but as mentioned above, it is small and Moreover, it is not possible to attach a case to this type of high-frequency coil, which tends to break when trying to mechanically fix the core to the core. It was difficult to wear it with the case.

An object of the present invention is to solve the above-mentioned conventional technical problems and provide a chip-shaped high-frequency coil that includes a case and a core that covers the winding.

The high-frequency coil of the present invention has a first core having flanges at both ends of the winding part and electrodes formed on the lower flanges, and a first core having a hole that is open at least on the lower side and covering the winding part. a second core located on the lower flange of the first core;
It is characterized by comprising a conductive case that covers the first core and the second core from above and is fixed to at least either the first core or the second core.

The following is a first example of the high frequency coil of the present invention.
This will be explained with reference to FIGS. 2 and 3. FIG. 1 is an exploded perspective view, and FIG. 2 is an assembled longitudinal sectional view.
FIG. 3 is a bottom view.

In FIGS. 1, 2, and 3, 1 is a first core, 2 is a second core, 3 is a metal case made of copper or the like, and 4 is a metal film. Both the first core 1 and the second core 2 are made of ferrite.

The first core 1 has flanges at both ends of the winding portion 5. The upper flanges 6 are circular, but the lower flanges 7 are approximately square, and the same circular protrusion 8 is located at a position opposite to the upper flanges 6. is provided. An electrode 9 is formed on the bottom surface of the lower flange 7 by printing and baking silver or the like, and although not shown, the lead of the winding 10 is passed through the groove 11 on the side surface of the lower flange 7 by series resistance welding or soldering. It is connected to the electrode 9 by attaching it.

The outer shape of the second core 2 is rectangular, but a cylindrical hole 12 with an open bottom is formed inside, and the upper collar 6 and the protruding portion 8 of the first core 1 are fitted into this hole 12. It's crowded. Further, a circular metal film 4 is adhered to the center of the upper surface 13 by printing and baking silver, for example. Note that the peripheral shape and size of the plane are
It is almost the same as the periphery of the lower flange 7 of the core 1.

The case 3 is open only on the lower side, and extends from above to cover the second core 2 into which the first core 1 is fitted and reach the side surface of the lower flange 7 of the first core 1.

The back side of the unopened upper surface 14 of the case 3 is fixed to the metal film 4 of the second core 2 by welding, and the lower lug 15 is fixed to the lower flange 7 of the first core 1.
The case 3 is fixed to the second core 2 and the first core 1 by being bent to the bottom surface of the case 3 .

FIG. 4, FIG. 5, and FIG. 6 are an exploded perspective view, an assembled longitudinal sectional view, and a bottom view, respectively, showing other embodiments of the high-frequency coil of the present invention.

The first core 16 has a circular upper flange 18 and a substantially square lower flange 19 at both ends of a winding portion 17, and an electrode 20 is formed on the bottom surface of the lower flange 19. A metal film 3 is provided at the center of the opposite side surface of the lower flange 19.
0 is coated. Note that the groove 21 plays the same role as the groove 11 of the core 1 in the first embodiment.

The second core 22 has a hole 23 that penetrates vertically in the center.
The first core 16 has a rectangular shape with
The portion from the upper collar 18 to the winding portion 17 is fitted into this hole 23. Further, the peripheral shape and size of the plane are approximately the same as the periphery of the lower flange 19 of the first core 16, and the height is approximately the same from the upper side of the lower flange 19 to the upper surface 24 of the upper flange 18. A rectangular metal film 26 is adhered to the opposing side surfaces 25.

Case 27 is open only at the bottom, and the first
The second core 22 into which the core 16 is fitted is covered from above and extends to the side surface of the lower flange 19 of the first core 16. The back sides of the side surfaces 28 and 31 of the case 27 are fixed to the metal film 26 of the second core 22 and the metal film 30 of the first core 16 by welding, and the lug 2
The case 27 is fixed to the second core 22 and the first core 16 by bending the portion 9 onto the bottom surface of the lower flange 19 of the first core 16 .

FIGS. 7 and 8 are an exploded perspective view and an assembled vertical sectional view, respectively, showing still another embodiment of the high frequency coil of the present invention.

The first core 32 has flanges at both ends of the winding portion 33, including a circular upper collar 34 and a square lower collar 35. A cylindrical protrusion 36 is formed at the center of the upper surface of the upper flange 34, and a metal film 37 is adhered to this protrusion 36. An electrode 45 is formed on the bottom surface of the lower flange 35.

The second core 38 has a rectangular outer shape, but has a cylindrical portion 46 with an open bottom and a cylindrical portion 4 inside.
A through hole 39 consisting of a small diameter portion 47 that is continuous with the upper surface 40 and penetrates through the upper surface 40 is provided.
the protruding portion 36 of the first core 32 and the cylindrical portion 4;
The upper flange 34 and the winding portion 33 are respectively positioned at 6, and the first core 32 is fitted into the through hole 39. A rectangular metal film 41 is adhered to the upper surface 40 with the through hole 39 in between. Also, the peripheral shape and size of the plane of the second core 38 are the same as those of the lower flange 35 of the first core 32.
The height is approximately the same as that from the upper side of the lower flange 35 to the portion of the protruding portion 36 to which the metal film 37 is adhered.

Only the lower side of the case 42 is open, and the first
The second core 38, into which the core 32 is fitted, is covered from above and extends to the side surface of the first core 32.

The back side of the upper surface 43 of the case 42 is the metal film 41 of the second core 38 and the metal film 3 of the first core 32.
7 by welding, and by bending the lug 44 to the bottom surface of the lower flange 35 of the first core 32, the case 42 connects the second core 38 and the first core 32.
Fixed.

In any of the embodiments, the lugs of the case stably fix the case to the first core and the second core, and also serve as terminals for connecting the case to the grounding circuit pattern. Alternatively, a metal film may be applied to the bottom surface of the lower flange at the bendable portion of the lug, and the lug may be fixed by welding the metal film. This has the advantage that the electrode and the metal film can be formed simultaneously by printing or the like. Furthermore, although the case has been described in which the case is fixed to the metal film by welding, it can also be fixed by soldering using a reflow soldering method.

In any case, the electrode and the metal film can be easily formed using the same technology such as printing or plating technology. The surface can also be soldered. Then, the case can be easily fixed from the outside while the case is placed over the core. When applying adhesive to the core to secure the case and core together, there is a risk that the adhesive may flow inside the case and adhere to unnecessary areas.
If a metal film is used, there is no such fear and the work is easy.

Furthermore, if the case is fixed to the core by high-temperature soldering or welding using a metal film, there is no fear that the adhesive will melt due to heat. Although the shape of the electrode is not the gist of the present invention, it can be modified in various ways, such as extending from the bottom surface to the side surface of the lower flange of the first core.

As described above, in the high frequency coil of the present invention, the first core having the wire wound thereon is covered by the second core, and the first core and the second core are further covered by the case. The case is fixed to at least one of the first core and the second core by welding or soldering. Therefore, no mechanical force is applied to any of the cores to cause damage, and manufacturing is easy. Even when the high-frequency coil of the present invention is actually manufactured on a circuit board, its characteristics will not become unstable due to electromagnetic influence from other circuit components, and its own leakage magnetic flux will not affect the surrounding circuit components. It has no negative effect on the. Of course, since it is a closed magnetic circuit type, the Q value is also improved. It also becomes mechanically stronger. Therefore, it is possible to obtain a chip-shaped high-frequency coil that is highly reliable both electrically and mechanically.

[Brief explanation of the drawing]

1, 2, and 3 are an exploded perspective view, an assembled vertical cross-sectional view, and a bottom view, respectively, showing an embodiment of the high-frequency coil of the present invention, and FIGS. 4, 5, and 6 are the FIG. 7 is an exploded perspective view, an assembled vertical sectional view, and a bottom view showing other embodiments of the high-frequency coil of the invention;
FIG. 8 is an exploded perspective view and an assembled longitudinal cross-sectional view, respectively, showing still another embodiment of the high frequency coil of the present invention. 1, 16, 32...first core, 2, 22, 3
8...second core, 3,27,42...case,
4, 26, 30, 37, 41...metal film, 5, 1
7, 33... Winding part, 6, 18, 34... Upper guard,
7, 19, 35... lower tsuba, 8, 36,... protruding portion, 9, 20, 45... electrode, 10... winding, 1
1,21...groove, 12,23...hole, 13,1
4, 24, 40, 43...Top surface, 15, 29, 4
4... Lug, 25, 28, 31... Side, 39...
...Through hole, 46...Cylindrical portion, 47...Small diameter portion.

Claims (1)

[Scope of utility model registration request] The first core has flanges at both ends of the winding part and electrodes are formed on the lower collar. a second core located above, covering the first core and the second core from above and at least covering the first core and the second core;
A high-frequency coil comprising: a conductive case fixed to a metal film attached to one of the cores;