JP3010569U - Chip inductor - Google Patents

Abstract

(57) [Summary] [Purpose] The inductance of a chip inductor using a drum-shaped ferrite core can be adjusted easily and precisely. [Structure] In a chip inductor consisting of a drum-shaped ferrite core having flanges at both ends and a winding wound around a cylindrical magnetic core part, in the drum-shaped ferrite core, one flange of the drum-shaped ferrite core is provided with a thickness of the flange. An opening having a depth equal to the above is pre-drilled, and an inductance adjusting hole connected to the opening can be formed in the magnetic core portion so that the inductance can be easily adjusted even after the chip inductor is mounted on the circuit board. .

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a chip inductor.

[0002]

[Prior art and its problems]

 Conventionally, in the case of adjusting the inductance of a wound-type inductor, for example, a cap core is attached to the upper part of the drum core around which the winding is wound to change the distance between the cap core and the drum core, or This is done by cutting a thread groove on the inner surface of a tubular core wound with a wire and moving the threaded core screwed inside up and down. In recent years, along with the miniaturization of electronic devices and the higher frequency range used, it has been required to reduce the size of inductors by making them into chips. However, when the wound inductor is made into a chip shape, it is difficult to use a cap core or a screw core as an inductance adjusting means because of its small size. Further, in a chip inductor using a drum-shaped ferrite core, cutting the flange of the drum-shaped ferrite core can be considered as a method of adjusting the inductance, but this method hardly changes the inductance. Therefore, in the conventional wire-wound chip inductor, a drum-type ferrite core around which a wire is wound is molded with a dielectric material to form a kind of LC filter, and a part of the peripheral surface of the dielectric material is cut off. By doing so, the inductance is adjusted by adjusting the Q value of the entire inductor. However, such a configuration has a drawback that it is difficult to adjust the inductance after the chip inductor is mounted on the circuit board.

[0003]

[Means to solve the problem]

 The present invention focuses on the fact that in a chip inductor using a drum-shaped ferrite core, the inductance changes substantially linearly by making a hole in the magnetic core and changing its depth and diameter. By pre-opening an opening with a depth equal to the thickness of the flange at the shaft center of one of the cores of the core, the inductance can be easily adjusted even after the chip inductor is mounted on the circuit board. It was made possible.

[0004]

【Example】

 FIG. 1 shows a cross-sectional view and a top view of a chip inductor of the present invention. In the figure, 1 is a chip inductor consisting of a drum-shaped ferrite core in which a coil 4 is wound around a column-shaped magnetic core 2 with a collar 3 at both ends, and 5 is an opening pre-drilled in the collar 3. Then, the opening is formed at a position which becomes the axial center of the drum-shaped ferrite core, and the depth d thereof is made equal to the thickness of the collar 3. Reference numeral 6 denotes an inductance adjusting hole connected to the opening 5 and opened in the magnetic core portion 3. The inductance of the chip inductor can be adjusted by changing the depth D and the diameter R thereof. FIG. 2 is a process diagram for adjusting the inductance of the chip inductor of the present invention, in which 7 is a circuit board, 8 is a laser irradiator, and 9 is another electronic component, when adjusting the inductance of the chip inductor. A laser irradiator 8 is arranged on the upper surface of the chip inductor 1, and a laser is radiated through the opening 5 to form an inductance adjusting hole 6 having an arbitrary depth. FIG. 3 shows the change rate characteristic of the inductance when the diameter R of the inductance adjusting hole 6 is fixed and the depth D of the hole is changed. The change rate ΔL (%) of the inductance is the inductance adjusting hole. It can be seen that the change rate is almost proportional to the depth D of 6 and that the slope of the change rate curve becomes smaller as the diameter R of the hole increases. As is clear from the figure, the inductance is hardly affected by the diameter and depth of the opening 5 formed in the collar 3. Here is a concrete example of a drum-shaped ferrite core with a total length of 2.9 mm, a magnetic core length of 1.9 mm, a magnetic core thickness (diameter) of 1.6 mmφ, and a diameter of both flanges of 3.5 mmφ. In a chip inductor having 100 mm mmφ windings and 120 μH inductance, the diameter R of the hole drilled in the magnetic core was set to 0.6 mmφ and the depth D of the hole was changed to 1.6 mm. Decreased linearly to 107 μH.

[0005]

[Action]

 In the present invention, since the opening equal to the depth of the flange is pre-drilled at the shaft center of one flange of the drum-shaped ferrite core, the position where the inductance adjusting hole is drilled can be accurately specified.

[0006]

【effect】

 Further, according to the present invention, as described above, since the opening equal to the depth of the flange is preliminarily formed at the shaft center of the flange of the drum type ferrite core, even after the chip inductor is mounted on the circuit board, Further, there is an advantage that the inductance of the chip inductor can be easily and precisely adjusted even when the electronic components are densely mounted on the circuit board.

[Brief description of drawings]

1 is a cross-sectional view and a top view of the chip inductor of the present invention, FIG. 2 is a process diagram when adjusting the inductance of the chip inductor of the present invention, and FIG. 3 is a change of the inductance in an embodiment of the chip inductor of the present invention. It is a figure which shows a rate characteristic.

[Explanation of symbols]

1 ... Chip inductor, 2 ... Winding, 3 ...
Magnetic core, 4 ... Tsuba, 5 ... Opening, 6 ... Inductance adjusting hole,

Claims (1)

[Scope of utility model registration request] 1. A chip inductor comprising a drum-shaped ferrite core having flanges at both ends and a winding wound around a columnar magnetic core portion, wherein the flange of the drum-shaped ferrite core is located at the axial center of the flange. A chip inductor in which an opening having a depth equal to the thickness of the opening is previously formed, and an inductance adjusting hole connected to the opening can be formed in the magnetic core portion.