Patent Application
20050104707
The invention relates to a coil former and a coil for circuit board mounting, comprising a prismatic or cylindrical winding form for at least one coil, and a base forming a single piece with said winding form and projecting out over said winding form at least in sections.
In wound components, by which is essentially meant inductive components in the power supply area, the coils on a winding form are generally connected to pins by routing the wire ends of one or more coils to corresponding solder pins, wrapping them around same and then soldering them. In another known solution, the coil consists of a broad and relatively rigid metal tape which can be soldered directly to a conductor track of a printed circuit board.
With the known solutions, either the labor input involved in fabricating the wound component as a whole is high, e.g. if the leads of the coil are to be soldered to solder pins, or difficulties arise with soldering to PCB conductor tracks, as is the case, for example, with the design using a wound metal tape.
The object of the invention is to simplify the design of the wound component for ease of mounting on a printed circuit board, thereby reducing costs.
This object is achieved according to the invention by forming leads for the one or more coils from the latters' winding wire and implementing them with their ends as solder pins which are accommodated in wire guides of the base and retained therein.
Thanks to the invention, one operation, namely the soldering of the coil to separate solder pins, can be dispensed with during fabrication of the coil former with the coil, and therefore of the wound component. As the ends of the winding wire are accommodated in the wire guides of the base and retained therein, there is produced a defined spacing of the solder pins corresponding to the drilled holes provided on the printed circuit board.
In a useful variant, wire guides are implemented in opposite sections of the base relative to the coil axis, resulting in increased stability of the wound component disposed on the printed circuit board.
In another useful variant it is provided that the wire guides are implemented as drilled holes in the base through which one end of the coil wire can be inserted, thereby providing a simple means of immovably fixing the solder pins.
On the other hand it may also be expedient for the wire guides to be implemented as outwardly open grooves in the base into which one end of the coil wire can be inserted from the outside. This variant is useful if the wire is relatively stiff because of its diameter or material characteristics, so that threading it through drilled holes after winding could prove difficult, it being advantageous in view of the desired secureness of the solder pins if the grooves are narrowed towards the outside, the coil wire snapping into place.
In a particularly practical variant it is provided that in one section of the base at least one wire guide is implemented as a drilled hole and in an oppositely located section at least one wire guide is implemented as an open groove. This embodiment provides on the one hand high stability and accuracy of fit of the solder pins and, on the other, allows ease of fabrication even with relatively stiff winding wire.
In usual and useful embodiments of the invention, the coil wire has a diameter of 1 to 4 mm and the coil wire is advantageously implemented as copper wire.
The invention together with further advantages will now be explained in greater detail with reference to embodiments illustrated in the accompanying drawings in which
As may be seen from
In this case the base 3 is rectangular and projects—not visible in plan view—out over the winding form 2 all round. Of importance for the invention are two sections 3a, 3b which are opposite relative to the coil axis 1 and in which wire section 3b and two outwardly open grooves 5 in the other section 3a. As may be best seen from
FIGS. 4 to 6 show the wound coil former according to FIGS. 1 to 3. In this case a winding or coil 6 is formed from two parallel wound wires 7, 8 e.g. made of enameled copper wire. For fabrication of the coil 6, the wires 7,8 with their beginnings are inserted through the drilled holes 4 (
It can therefore be seen that with the invention the otherwise customary separate leads for the solder pins are formed by the winding wire of the coil and merge directly into the solder pins as one piece.
In the embodiment according to FIGS. 4 to 6, the coil 6 is completed by an E-core 11 consisting of two halves, plastic spacers 12 glued into the air gap also mechanically fixing the two core halves. The winding of the coil 6 can if required also be fixed using adhesive, e.g. an artificial resin. The asymmetrical arrangement of the solder pins 9 ensures correct mounting of the entire wound component on a printed circuit board 10.
In the exemplary embodiment shown, the coil 6 is a single winding which is, however, dual-wound in order to allow a high current density with reduced spin effect and moderate wire diameter. All variants of coils or windings are possible within the scope of the invention. In the case of an individual, single-wound coil, two terminals or solder pins will naturally also suffice. A coil former suitable for this purpose is shown e.g. in
Of course the term “coil” should here likewise also include tapped windings, such as a plurality of windings of a transformer or transducer. In these cases also, three or more solder pins will be required.
| Number | Date | Country | Kind |
|---|---|---|---|
| A 218/2002 | Feb 2002 | AT | national |
This application is the US National Stage of International Application No. PCT/AT03/00037, filed Feb. 10, 2003 and claims the benefit thereof. The International Application claims the benefits of Austrian application No. 218/2002 filed Feb. 12, 2002, both of the applications are incorporated by reference herein in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/AT03/00037 | 2/10/2003 | WO |
