DE1954206B2 - Small adjustable coil for communications equip. - has two-part core with toroidal coil in upper part - Google Patents

Abstract

The small adjustable coil, for communications equipment, has the core's base formed by a flat disc and its upper part formed by a bell-shaped piece with a deep circular groove cut into it to accept the toroidal coil. The two core parts are held together by a circular lead spring on top of the core. The spring acts between core top and the U-shaped bracket that holds the whole assembly to the insulating support board, e.g. a p.c. board. The contacts pass through the core's base disc and through the p.c. board. The coil is protected from damage and the spread of the electrical field is lessened.

Description

The invention relates to an adjustable two-part pot core coil, in particular a ferrite core coil No construction method, for telecommunications equipment and for installation in printed circuits, where how this is known, for example, from British patent specification 4 42 849, the inductance adjustment by The two core halves are rotated against each other about an axis of rotation that is concentric to the shell parts, and which are proposed in patent 19 17 897 and specified in the preamble of the claim Has features.

From DT-AS 12 08 425, for example, a method is known in which with eccentrically arranged ring-shaped recesses formed on the central lugs and lying on top of one another shell core halves are rotated against each other for inductance adjustment, whereby during the adjustment of the two Core halves compressive pressure of a leaf spring with an auxiliary tool temporarily significant is reduced or canceled and then the two core holsters lying in a U-shaped holder) with the help of another tool, which is connected to the upper core half in the opening of a Metal plate engages, are twisted against each other.

The main patent relates to an adjustable pot core coil of the type mentioned at the beginning, in the case of the easily rotatable upper core part the centricity: with the fixed core base during the calibration process should be preserved. In addition, according to the main patent, the pot core coil should consist of as little as possible Assembled individual parts and - as already mentioned - suitable for installation in printed circuits be.

For this purpose, the main patron suggests that the fixed lower core part be cuboid and laterally open, the rotatable upper core part is round and closed is designed that both core halves have an asymmetrically shaped central slug that both core halves placed over a coil body carrying the wire connection pins and from one resilient brackets are held together that a disc is centered between the bracket and the rotatable upper core part is arranged, which has recesses for a correspondingly shaped adjustment key and in a hole in the bracket is guided, and that the lower fixed core half at least to the Places where the retaining bracket is pushed on has a larger diameter than the upper one rotatable core half.

This results in the advantages that, due to the geometrically different shapes of the cores, the retaining bracket laterally only touches the fixed lower core part, so that the rotatable upper part does not have any additional lateral frictional forces through strips on the temple legs absorbs that between the temple and the core upper part lying disc absorbs the ironing pressure in the middle and on the lower part of the core! resting Edge distributed, that through the centric guidance of the disc in the bracket and the core upper part during the adjustment is rotated centrically to the lower part and that when assembling the coil the cohesion without Screwing, soldering, gluing or the like. Is effected.

The present invention is based on the object of providing _{better magnetic and mechanical shielding for the coil winding, which is partially exposed in the area of the main coil as a result of the partially broken wall of the} lower core part in the vicinity of the coil body parts.

With an adjustable miniature coil for devices Communication engineering and for installation in printed circuits, consisting of one of the wire connection pins supporting bobbin, a two-part ferrite core surrounding the bobbin, its core halves have an asymmetrically shaped central slug, with the core upper part as a round, closed Cup core half formed and rotatable for inductance adjustment with respect to the fixed lower core part is, as well as a resilient bracket holding the core halves together and one on the core upper part The invention provides a centering disk that lies against rotation and is guided in a bore in the bracket to solve the problem or to further improve the subject matter of the main patent before that the core upper part is bell-shaped with a substantially corresponding to the dimensions of the coil annular recess and the lower core part as a flat disc with a height of approximately one Bobbin flange formed corresponding recess and with recesses for the bobbin pins is provided.

With this design of the shell core parts, the problem posed is solved perfectly; d. H. in particular the coil winding largely protected from damage and improved coil shielding, i.e. a considerable reduction in the stray electrical field is achieved. Turns out to be further improvement the very simple and therefore easy to manufacture lower core part.

Embodiments of the invention are explained in more detail below with reference to the drawing.

F i g. 1 shows an adjustable miniature coil according to the invention in plan view;

F i g. 2 and 3 show a section according to the line I-I in Fig. 1; there is a centering disk in FIG made of plastic and in FIG. 3 a centering disk made of metal is used.

P. 54

A fixed lower core part 1 made of magnetic material is a flat disk with a recess 19 formed, in which a wound and dip-soldered | er bobbin 2 with its facing ring f The rest of the coil receiver part is bell-shaped in an annular recess 20 trained Kernobteileci 3 housed. One in the exemplary embodiment according to FIG. 2 injected Disc 5 made of plastic or one in the exemplary embodiment according to FIG. 3 disc 4 stamped from metal, the are each provided with a Veil 10 serving to center a bracket 7, is on the lower part of the core 1 facing away from the end face of the upper core part 3 is placed. The U-shaped resilient bracket 7 is such Cover the lower core part 1, the upper core part 3 and the disc 4 or 5 inserted that the bent ends 15 of the bracket reach under the lower core part 1. The so assembled pot core coil is with the free ends 16 of the z. B. existing from Neusilbo-r Bracket 7 and with bobbin pins 11, which are attached to the bobbin 2, in an etched and drilled Circuit board 8 plugged in and with appropriate electrical power connection elements, for. B. Conductor tracks, soldered. For guiding the bobbin pins 11 through the lower core part 1, its flat disc has recesses aiii, not shown in the drawing.

After soldering the coil, twisting the shell core upper part 3 with a key that is in corresponding recesses 12 of the disk 4 or 5 engages, the inductance adjustment can be made. Since the coefficient of friction between the disc 4 or 5 and the upper core part 3 is greater than on the Sliding surfaces between the two shell core parts 1, 3 and also formed as a tab 18 parts of the punched disc 4 or elevations 17 of the injection-molded disc 5 engage in depressions in the upper core part 3, an additional gluing of the pane 4 or 5 to the core upper part 3 is not necessary.

After the inductance adjustment, the set value can be secured by gluing the shell core parts 1 and 3 at 9 using glue, varnish or the like.

1 sheet of drawings

Claims (1)

Claim: Adjustable miniature coil for telecommunications equipment and for installation in printed circuits, consisting of one of the wire connection pins supporting bobbin, a two-part ferrite core surrounding the bobbin, its Core halves have an asymmetrically shaped central slug, with the core upper part as a round, closed shell core half and designed for inductance compensation compared to the fixed Core lower part is rotatable, as well as a resilient bracket holding the core halves together and one that rests on the upper core part in a torsion-proof manner and is guided in a hole in the bracket Centering disc according to Patent 19 17 897, characterized in that the core upper part (3) bell-shaped with an annular shape substantially corresponding to the dimensions of the coil (2) Recess (20) and the lower core part (1) as a flat disc with a height of approximately one Spool flange corresponding recess (19) formed and with recesses for the bobbin pins (lt) is provided.