JPS58124213A - Chip type variable inductance element - Google Patents

Abstract

PURPOSE:To obtain an accurate L value by molding a molding material mixed with magnetic powder between collars of a magnetic core. CONSTITUTION:A magnetic core 13 is formed of collars 12a, 12b of a rectangle provided at both ends of a coil mount 11 and the coil mount 11. Insulating layers 14a, 14b which are made of nonmagnetic material are respectively formed on the lower surfaces of the collars 12a, 12b, electrodes 15a, 15b are laminated on the lower surfaces, and both ends of a coil 16 are respectively connected to the electrodes. Then, thermoplastic resin 17 made of polyethylene or polyurethane mixed with magnetic powder having large magnetic permeability such as Mn-Zn ferrite is filled and cured between the collars 12a and 12b in such a manner that the mixture ratio of the magnetic powder with the resin is substantially at maximum 5:1 by weight and at minimum 1:5. In this case, the collars 12a and 12a of the core 12 are fixed with the resin 17 mixed with the magnetic powder having large magnetic permeability between the collars. Accordingly, the leakage magnetic flux which crosses the electrodes 15a, 15b can be prevented, and can also be prevented by the insulating layers 14a, 14b, thereby maintaining high Q characteristic.

Description

Detailed Description of the Invention The present invention provides a magnetic core formed from a coil winding portion and a pair of flanges provided at both ends of the coil winding portion, and a magnetic core formed from a coil winding portion (the coil winding portion) of the magnetic core. The invention relates to a chip-type variable inductance element consisting of a coil mounted thereon,
It is suitable for use when forming high frequency circuits on printed wiring boards, etc.

Conventionally, a chip-type inductance element has a cylindrical coil winding part (1) and circular flanges (2a) (2b) provided at both ends of the coil winding part (as shown in FIGS. 1 and 2). A coil (4) is wound around the coil winding portion (1) of the magnetic core (3).Both ends of the coil (4) are the electrodes (5aX5b) provided on the lower surface E of the flange (2aX2b), respectively.
+ is connected, solder this electrode (5aX5b) (6a)
(6b) 4c, J:, Riff” lint wiring board (7)
I'm soldering it.

However, in the structure of C, the leakage magnetic flux is
b) Cutting (cutting) causes a significant deterioration of the Q value.Therefore, in the past, the Q characteristic was improved by improving the material valley or changing the shape, etc., or the improvement was not made sufficiently. Also, the mounting area cannot be avoided.

Generally, in this type of inductance element,
Due to slight errors in the winding of the coil (4), the shape of the magnetic core (3), etc., it was difficult to obtain an accurate L value. Therefore, conventionally, as shown in Figs. 6 and 4, a trimmer core (8) was screwed in from the side of one flange (2b).
The L value was adjusted by adjusting the amount of screw tightening, but since there is a limit to how small the trimmer core can be made, it is difficult to adjust with a small size, so it is not applicable to small chip type inductance elements. I was able to do it.

The present invention was made in view of the above-mentioned circumstances, and its purpose is to prevent as much as possible the leakage magnetic flux that cuts the electrodes.
To provide a chip-type variable inductance element that maintains a higher Q characteristic and can adjust the L value to obtain an accurate L value depending on the purpose.

In order to achieve this purpose, the chip-type variable inductance element according to the present invention (in this case, molding between the flanges of the magnetic core with a molding material mixed with magnetic powder) makes it easier for magnetic flux to leak through the element. It is characterized by preventing as much as possible the leakage magnetic flux that cuts the electrode (and by scraping off the molded material together with the magnetic powder mixed therein, the L value can be adjusted).

Embodiment 7j- of the present invention will be described below with reference to FIGS. 5 and 6. C (in these figures, old code) is the coil winding part, and the rectangular parallelepiped flanges (128 x 12b) provided at both ends of this coil winding part (11) and this coil winding part (1
1+ forms a magnetic core θ3) made of, for example, ferrite. Insulation N (14aX14b) made of a non-magnetic material such as a glass epoxy plate is provided on the lower surface of the flange (12aX 12b), and electrodes (158X15b) made of a copper plate or the like are laminated on the lower surface.
The electrodes (15aX15b) are connected to both ends of the coil fl131 wound around the coil winding portion aυ. Note that the above insulating layer (14aX 14b)
The practical thickness of the material varies depending on its material and size, but it may be 0.25 mm! It is preferable that it is J or more.

Next (the code aη is a thermoplastic resin such as polyethylene or polyurethane mixed with magnetic powder with high magnetic permeability such as Mn-Zn ferrite, and the flange part (12aX
12b) This was injected and cured.

In this case, the mixing ratio of magnetic powder and resin may be variable depending on the purpose (or, from a practical point of view, the maximum weight ratio (
The minimum value may be 5:1, and the minimum value may be 1:5.

The chip type variable inductance element configured as described above has its electrodes (15a x 15b) soldered (18a x 18b) on a predetermined pattern on the printed wiring board (7).
), and both ends of the coil (16) are connected to the electrodes (158X15b) as described above.In this case, the flange (12aX12b) of the magnetic core (131)
) is solidified with resin aη mixed with magnetic powder having high magnetic permeability as described above, so leakage magnetic flux tends to pass through this part. Therefore, leakage magnetic flux cutting through the electrode (15aX15b) is prevented as much as possible by the presence of the resin ar, and also by the non-magnetic insulating layer (143X14b), thus maintaining even higher Q characteristics. can do.

In addition, the resin (17) can be cut out by laser trimming or the like to remove co-blocks with the magnetic powder with high magnetic permeability contained therein, such as grooves (IcJ). Therefore, read the L value with a meter. However, by scraping off the resin α7), it is possible to obtain a chip-type variable inductance with a desired accurate L value.

Furthermore, since the coil (16) is embedded in the resin αη, the fill is protected from the resin and will not be damaged.
12aX 12b) (The first floor is solidified as one piece with resin αη, so the easily broken magnetic core is reinforced by resin ζ.

As explained above, the chip-type variable inductance element of the present invention prevents leakage flux that cuts the electrodes as much as possible, so it is possible to maintain high Q characteristics and
Because it is solidified with resin, it strengthens the weak magnetic core and coils. Furthermore, by scraping off the resin, a chip-type variable inductance element with desired accurate L and Q values can be obtained. Therefore, the miniaturization of chip-type variable inductance elements is promoted, and even in the actual equipment of components for hybrid integrated circuits and printed wiring boards, miniaturization, weight reduction, and cost reduction are further promoted, which is advantageous. .

[Brief explanation of the drawing]

Figure 1 is a front view of a conventional chip-type inductance element.
Figure 2 is a front view of the inductance element shown in Figure 1.
FIG. 6 is a front view of a conventional chip-type variable inductance element, FIG. 4 is a side view of the inductance element shown in FIG. 6, and FIG. 5 is a front view of a chip-type variable inductance element showing an embodiment of the present invention. , FIG. 6 is a (1111 plane view) of the inductance element shown in FIG.
・・・・・・・・・・・・・・・ Coil winding part (12
aX12b)--Flame (13)...Magnetic core (
This is a coil for the old... Agent Masaru Saturn〃 Yoshio Tsunekako〃 Toshiki Sugiura

Claims (1)

[Claims] It consists of a magnetic core formed from a coil winding part and a pair of flanges provided at both ends of the coil winding part, and a coil wound around the coil winding part of the magnetic core, and a coil is wound between the flanges. A chip-type variable inductance element characterized by being molded with a molding material mixed with magnetic powder.