JPH0113387Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to an improved structure of a coil device.

BACKGROUND ART A conventional coil device has a structure as shown in FIG. 1, for example, in which a thread groove for screwing into a ferrite core 3 is provided on the inner surface of a bobbin cylinder 1. A coil 2 is wound around the outer periphery of the bobbin cylinder 1,
4 and 5 are lead terminals of the coil 2, which are soldered to the wiring board 6. According to this configuration, the ferrite core 3 is rotated to vary its vertical position within the bobbin cylinder 1, thereby adjusting the inductance of the coil device. And in some cases, ferrite core 3
Since the bobbin cylinder 1 is fixed to the wiring board 6 in a state where the ferrite core 3 presses the wiring board 6 due to the rotation of It was hot.

DISCLOSURE OF THE INVENTION The present invention was proposed in view of the above points, and even if the ferrite core is casually rotated with the bobbin tube fixed to the wiring board, the thread grooves and ferrite core inside the bobbin tube as described above will not be removed. The purpose is to provide a coil device that will not be damaged.

Therefore, in the present invention, a rotating cylindrical body is slidably fitted into the inside of the bobbin cylinder, and the inner surface of the cylindrical body and the ferrite core are screwed together.

Therefore, according to this configuration, when the ferrite core is screwed into the bobbin cylinder by a predetermined amount or more, the cylindrical body that fits inside the bobbin cylinder idles as the ferrite core rotates, and the ferrite core is not screwed into the bobbin cylinder. Damage to the thread groove and ferrite core can be prevented.

BEST MODE FOR CARRYING OUT THE INVENTION Fig. 2 is a sectional view showing one embodiment of the invention;
The figure is a sectional view showing another embodiment of the present invention. Further, among the reference numerals shown in FIGS. 2 and 3, the same reference numerals as in FIG. 1 indicate the same parts as in FIG.

In FIG. 2, reference numeral 11 denotes a bobbin cylinder, into which a cylinder 17 having a threaded groove on its inner surface is fitted. Reference numeral 13 denotes a ferrite core that is screwed into the thread groove, and when the ferrite core 13 presses the wiring board 6 when adjusting the inductance, the cylindrical body 17
slides on the inner surface of the bobbin cylinder 11 and rotates idly,
The ferrite core 13 does not press the wiring board 6 more than necessary.

Next, referring to FIG. 3, reference numeral 21 denotes a bobbin cylinder which is open only at the top, and a cylinder 18 having a threaded groove on its inner surface is fitted into the cylinder. 13
is a ferrite core, and in the configuration shown in FIG. 3, when the ferrite core 13 presses the base of the bobbin tube 21, the cylinder body 18 slides on the inner surface of the bobbin tube 21 and rotates idly.

In order to do this, the contact resistance of the sliding contact between the inner circumferential surface of the bobbin tube and the outer circumferential surface of the tube is created by the thread groove formed on the inner circumferential surface of the tube and the ferrite core being screwed together. This can be easily done by making it larger than the contact resistance.

In other words, when the ferrite core is not screwed in more than a predetermined amount, the contact resistance due to the sliding contact between the inner circumferential surface of the bobbin tube and the outer circumferential surface of the tube is caused by the contact resistance between the thread groove formed on the inner circumferential surface of the tube and the ferrite core. The ferrite core will not idle because it is greater than the contact resistance when it is screwed together, but if the ferrite core is screwed in more than a certain amount, the resistance when it is screwed in is greater than the contact resistance when it slides into contact with the inner circumferential surface of the bobbin tube and the outer circumferential surface of the cylinder body, i.e. The contact resistance when the ferrite core is screwed into the threaded groove formed on the inner circumferential surface of the cylindrical body becomes larger, so that the ferrite core starts to idle.

As described above, according to the present invention, when the ferrite core is screwed into the bobbin cylinder by a predetermined amount or more, as the ferrite core rotates, the cylinder fitting inside the bobbin cylinder idles, and the ferrite core is not screwed into the bobbin cylinder. This is effective in preventing damage to the thread groove and ferrite core.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional example, FIG. 2 is a sectional view showing one embodiment of the present invention, and FIG. 3 is a sectional view showing another embodiment of the present invention. 11, 21... Bobbin cylinder, 13... Ferrite core, 17, 18... Cylindrical body.

Claims (1)

[Claims for Utility Model Registration] A bobbin cylinder around which a coil is wound, and a cylinder whose outer circumferential surface is in sliding contact with the inner surface of the bobbin cylinder with a predetermined contact resistance, and a threaded groove is formed on the inner circumferential surface. , comprising a ferrite core that is screwed into the thread groove with a contact resistance smaller than the contact resistance, and when the ferrite core is screwed into the bobbin cylinder by a predetermined amount or more, as the ferrite core rotates. A coil device characterized in that the cylindrical body rotates idly.