Inductive electronic component for transmission by flat contacts.

p0001The present invention relates to an inductive electronic component to the carry plate, having a pulley composed of two integral flanges of a mandrel on which is wound an electric coil whose ends are respectively connected to an electrode, a mechanical protection means such as a resin coating the coil substantially to height of the cheeks.

p0002Electronic components for flat postponement are commonly known under the name "chip". These known components, so that inductive capacitive, have a generally parallelepiped shape provided with two flat electrodes arranged on two side faces of the parallelepiped permit flat deferral said component. In this flat transfer technique, for example these components placed in chargers generally feed automatic insertion machines and are positioned on the printed circuit to which they are intended with the aid of a glue. When the circuit is completely filled with different assets and liabilities that must be connected, they are then connections to printed circuit tracks by the technique called "wave soldering" to "hardened" or any other connection system well known to the art.

p0003Inductive components of the chip are known, for example from French patent 2 509 529. However, it is sufficient to refer to the description and accompanying drawings in this patent to easily understand that the solution proposed therein is particularly complicated. Indeed, it uses a pulley on which is wound inductive coil, said pulley having side cheeks whose end faces have a hollow form into which take up a metallization on which rests a paw , the assembly being embedded in a resin and then said curved lug.

p0004Contrary to what is stated in said patent, the applicant believes that the eddy current loss problems, as well as the value of the quality factor Q of the inductor thus formed can be improved through a much simpler structure, using electrodes obtained by metallization.

p0005The electronic component according to the invention is characterized in that the flanges of the pulley are covered substantially exclusively on their outer side with a conductive electrode layer, in that each flange and its conductive layer comprise a groove extending parallel the mandrel and at least to the extension thereof in the cheeks, and in that each end of the winding is respectively fixed in each groove by means of a soldering ensuring the electric contact between the electrodes and the ends of the winding. Preferably, this weld will be performed by an electrically conductive solder, said solder at least partially filling each of the grooves.

p0006According to a preferred embodiment, the bottom of the gorge is located in the extension of the mandrel. Preferably it will include at least a flat face that will extend through a plane portion in each groove.

p0007The component thus formed, which does not have the disadvantages of chips of the same type of prior art, namely, the eddy current losses a very low coefficient of quality Q, has the essential advantages of manufacturing simplicity leading to reduced production costs.

p0008In particular, it is noted in the characteristic structure of the invention, two particularly important points thereof may optionally be used alone in so far as the improvement provided by the other point is not regarded as essential in the intended application. The first point is the presence of a groove in each of the flanges of the pulley groove through them from their inner surface to their external surface, and extending at least up to the mandrel of the pulley ( preferably but stopping at this level). In this way, it greatly simplifies the problem of fixing and / or welding of the ends of the windings of the inductor. Furthermore, we choose the depth of the groove (ie the height of the cheek) sufficiently large so that the wire can be inserted therein and secured with a solder for example tin-lead type without that -ci not extend to the outside of said groove. In this manner, the component of the coating using an epoxy type resin, for example, may be limited to the external dimension of the cheeks. In this way, well formed component has external dimensions equal to the dimensions of the pulley used. There is added, with this structure, no extra thickness to the pulley to realize the component. A second important point of the invention, which, combined with the previous provides the same benefits of low outside dimensions, is the use of metallization of electrodes deposited on the outer surface of the cheeks of the pulley. In this way, it increases only weakly the component width while keeping the height and thickness of the pulley. This structure also has the great advantage of complete indifference as to its component welding face on the circuit. Indeed, in the case of an outer shape of rectangular block, for example when forming the electrodes on two opposite side surfaces (outer surface of the cheeks), the component may be welded on the circuit being positioned on the any of the other four faces of the parallelepiped, as is readily understood by the following.

p0009In general, the wheel may be plastic, ceramic or preferably ferrite or iron powder agglomerated to increase the component of the magnetic properties. Whatever the material used, the wheel may be either molded or obtained from a rectangular bar rec tified. The outer shape of the wheel may either be cylindrical (as described for example in the French patent cited above) or parallelepiped with a central mandrel constituting a portion of smaller section than the side plates secured to the mandrel.

p0010The electrodes deposited on the outer faces of the flanges of the pulley will preferably be carried out by dipping in a silver bath, silver-palladium, or deposited by screen printing, by chemical deposition, electroplating or by vapor deposition, etc ..., manner known per se. In the case of silkscreened deposition, the selected inks must be appropriate, particularly in the case of filing before firing ceramic or ferrite.

p0011The grooves formed in each cheek will be either directly by molding or by grinding, in the latter case before or after deposition of the electrodes. In case the pulleys and the grooves are made by casting, dip coating or screen printing electrodes provides course directly appropriate grooves in the corresponding part of electrodes.

p0012The winding wire is arranged at each end thereof in said grooves, and welded into said groove electrically, by pressure, ultrasonic (or by the technique known as "ball bonding" used in microelectronics), etc .. . or using tin or tin-lead solder so as to mechanically secure the wire and the pulley on the one hand, and to ensure an electrical connection between the end of the winding and the other electrode share.

p0013The component of the final coating is generally effected by using suitable molds so as not to contaminate the component electrode ends, or by enrubanage adhesive films or plastic or son with a sleeve thermostractable plastic, etc ...

p0014The invention will be better understood with the following examples of embodiment, given without limitation, in conjunction with the figures which show: <ul><li>- Figure 1, a perspective view of the component of the pulley according to the invention;</li><li>- Figure 2 is a bottom view of the finished component;</li><li>- Figure 3, an end view of the same component;</li><li>- Figure 4, a sectional view of said component in a plane parallel to the grooves.</li></ul>

p0015In Figure 1 is shown the pulley according to the invention coated with its end electrodes. This form of pulley is composed of a mandrel 1 itself parallelepipedal bearing at each of its ends parallelepiped cheeks 2 and 3. The outer faces of said flanges 2 and 3 are covered with metal layers respectively of electrodes 4 and 5. side face of each flange 2 and 3 comprises a groove 6 and 7 disposed on the same side relative to the chuck 1. each groove 6 and 7 extends up to the face 8 of the mandrel 1 that extends in a planar portion, 10 and 9 respectively.

p0016In Figure 2 is shown a side view of the component according to the invention obtained from the pulley of Figure 1, wound and resin-coated. In this figure and the following figures, the same elements have the same references. The winding of the wire 12 is wound around the mandrel 1 and ends with its ends 13 and 14 placed respectively in the grooves 6 and 7. The pulley is filled between its lateral cheeks at the mandrel with a resin 11 of epoxy type coating the winding 12 and arriving at said cheeks.

p0017The end view of the Figure 3 component provides insight fixing each winding end into the corresponding groove. The tip 13 is made mechanically secured to the pulley by introducing into the groove 6 and fixation using a tin-lead solder 15. This type of tin-lead solder 15 also electrically connects the end 13 and the electrode 4. during filling with epoxy resin 11, the portion of the possibly not filled with welding groove is completed with the resin 11.

p0018Figure 4 which is a sectional view parallel to the median plane of the grooves 6 and 7 shows the finished component.