Contact part for electrically connecting end-face contact layers on the end faces of a plastic film capacitor winding of an encased electric single-phase or three-phase capacitor, and encased electric single-phase and three-phase capacitors comprising same

The invention relates to a contact part (20) for electrically connecting end-face contact layers on the end faces of a plastic film capacitor winding (10) of an encased electric single-phase or three-phase capacitor to a terminal wire (18, 34) or a connecting wire, comprising a preferably flat contact support with a terminal region for contacting a terminal wire (18, 34) or a connecting wire; comprising at least one contact piece (26) with at least one contact tip, said contact piece (26) extending upwards or downwards from the contact support in a substantially vertical manner, in order to establish an electric connection to an end-face contact layer (12, 14) by pressing the contact tip into said end-face contact layer (12, 14); and comprising a penetration depth-limiting device for limiting the penetration depth of the contact tip or the contact tips in the end-face contact layer (12, 14). The invention also relates to encased single-phase and three-phase capacitors comprising said contact part.

The present application is a National Stage application of International Patent Application Number PCT/EP2012/002083 filed May 15, 2012, which claims priority to German Patent Application 102011104255.9, filed Jun. 15, 2011, both of which are incorporated herein by reference.

The present invention relates to a contact part for electrically connecting end-face contact layers on the end faces of a plastic film capacitor winding of an encased electric single-phase or three-phase capacitor comprising a terminal wire or a connecting wire and to an encased electric single-phase capacitor and to an encased electric three-phase capacitor.

For example, DE 10 2005 045 978 B3 discloses encased electric single-phase and three-phase capacitors of the type mentioned at the outset. In order to produce such capacitors, capacitor windings consisting of metalized polypropylene film are sprayed on both end faces with metal, generally zinc. The resulting end-face contact layers (contact areas) are connected to the connecting and terminal wires by means of soldered joints. The connecting and terminal wires usually consist of copper. Some are also tin-plated on the surface and can therefore be soldered very easily per se. The end-face contact layers consisting of zinc of the capacitor windings can only be soldered with great difficulty, however. This means that considerable supply of heat with relatively high soldering temperatures is required. Very aggressive fluxes and, if possible, lead-containing solder are required for a good soldering result. In addition, well trained personnel are required in order to achieve consistently good soldering.

The invention is therefore based on the object of enabling simpler and therefore less expensive production of encased electric single-phase and three-phase capacitors.

This object is achieved according to the invention by a contact part for electrically connecting end-face contact layers on the end faces of a plastic film capacitor winding of an encased electric single-phase or three-phase capacitor comprising a terminal wire or a connecting wire, comprising a preferably planar contact carrier with a terminal region for making contact with a terminal wire or a connecting wire, at least one contact piece which extends upwards or downwards substantially perpendicularly from the contact carrier and has at least one contact tip for producing an electrical connection to an end-face contact layer by the contact tip being pushed into said end-face contact layer, and a penetration depth limitation device for limiting the penetration depth of the contact tip or the contact tips in the end-face contact layer. The terminal wire or connecting wire may be quite generally a terminal conductor or connecting conductor for example consisting of litz wires.

Furthermore, this object is achieved by an encased electric single-phase capacitor comprising a housing, a housing cover, a plastic film capacitor winding which is arranged in the housing and whose end faces are each provided with an end-face contact layer, and two terminal wires which are passed through the housing cover, characterized in that the terminal wires are electrically connected to the end-face contact layers via a respective contact part wherein the contact parts are electrically connected to the respective end-face contact layer without the use of solder.

In addition, this object is achieved by an encased electric three-phase capacitor comprising a housing, a housing cover, three plastic film capacitor windings, which are arranged one above the other in the housing, are delta-connected to one another and whose end faces are each provided with an end-face contact layer, and three terminal wires which are passed through the housing cover, characterized in that the terminal wires are electrically connected to the corresponding end-face contact layer of the capacitor windings via a respective contact part, wherein the contact parts are electrically connected to the respective corresponding end-face contact layer without the use of solder.

In accordance with a particular embodiment of the contact part, at least one contact piece extends upwards substantially perpendicularly from the contact carrier and at least one contact piece extends downwards substantially perpendicularly from the contact carrier.

Advantageously, the contact carrier is substantially ring-shaped, and the terminal region is a terminal lug, preferably in the plane of the contact carrier. The two abovementioned measures can of course also be provided independently of one another.

Favorably, a plurality of contact pieces is preferably provided equidistantly on the outer edge of the ring-shaped contact carrier and extends upwards or downwards substantially perpendicularly uniformly therefrom.

It is also conceivable for a plurality of contact pieces to be preferably provided equidistantly on the inner edge of the ring-shaped contact carrier and to extend downwards or upwards perpendicularly uniformly therefrom. Thus, the contact pieces can be provided only on one side (at the top or at the bottom) or on both sides.

In accordance with a further particular embodiment of the invention, the penetration depth limitation device has a plurality of resting pieces with resting areas or resting points.

Favorably, the resting pieces or some of said resting pieces are preferably provided equidistantly on the outer rim of the ring-shaped contact carrier and extend upwards or downwards substantially perpendicularly uniformly therefrom.

Provision can also be made for the resting pieces or some of said resting pieces to be preferably provided equidistantly on the inner rim of the ring-shaped contact carrier and to extend upwards or downwards substantially perpendicularly uniformly therefrom. Precisely in the same way as the contact pieces, the resting pieces can therefore be provided on one or both sides.

Favorably, the base material of the contact part is preferably metal with good electrical conductivity, preferably brass or copper. However, it is also conceivable to use, for example, spring steel or generally electrically conductive material, such as, for example, electrically conductive plastic.

Advantageously, the base material has a tin plating.

Favorably, in the case of the encased electric three-phase capacitor, in each case one of the contact parts is provided on the end faces of the uppermost and lowermost capacitor windings, and in each case one of the contact parts is provided between the capacitor windings for making contact with each of the two adjacent end-face contact layers, and a connecting wire for electrically connecting the uppermost contact part to the lowermost contact part is provided. In each case one contact part with contact pieces protruding on one side, to be precise towards the respective end-face contact layer, can be provided on the uppermost and lowermost capacitor windings, while contact parts with contact pieces protruding in each case on both sides should be provided between the capacitor windings. In this case, a corresponding arrangement of resting pieces of course also makes sense.

Favorably, in the case of the encased electric three-phase capacitor, the connecting wire is electrically connected to the uppermost and lowermost contact parts by spot welding, crimping or soldering.

In accordance with a particular embodiment of the encased capacitors, the contact parts are at least partially pressed into the respective end-face contact layer. For example, once the capacitor windings or capacitor winding column have been installed in the housing, the contact tips can be pressed into the end-face contact layer(s) with a corresponding press-in pressure. The compressive force can be maintained until the holding ring or the holding bead is brought into position. Thus, the contact tips remain in the pressed-in position.

Advantageously, the terminal wires are electrically connected to the respective contact part by spot welding, crimping or soldering.

In accordance with a further particular embodiment of the invention, the plastic film capacitor windings are produced from plastic films provided with a metal layer, in particular metalized polypropylene films.

Finally, provision can alternatively be made for the plastic film capacitor windings to be produced from metal films which are insulated from one another by a plastic film.

The invention is based on the surprising discovery that the encased electric capacitors can be produced more easily and therefore at less expense by virtue of the electrical connection to the end-face contact layers without the use of solder. For example, in the case of an encased electric three-phase capacitor, i.e. with three capacitor windings, in total nine critical soldering operations and two connecting wires are no longer required. In addition, the quality of the electrical connection has a longer life because the films are no longer damaged by the heat during the soldering operation and therefore the electrical connection between the vapor-deposited film and the end-face contact layers is not weakened, and smaller fluctuations in quality occur since production using a precisely adjustable pressure for pushing or pressing the contact parts into the end-face contact layers is possible. In addition, automation of the production of the encased capacitors (power capacitors) or some of said encased capacitors is more easily possible.

FIG. 1shows a plastic film capacitor winding10, whose end faces are each provided with an end-face contact layer12and14consisting of zinc, for example. A terminal wire18extends from the top to the bottom through the hollow capacitor winding core16. The upper end of the terminal wire18is passed through a housing cover after production of an encased electric single-phase capacitor with said plastic film capacitor winding10.

The lower end of the terminal wire18is electrically connected to a contact part20shown inFIG. 6by spot welding, crimping or soldering. As can be seen fromFIG. 6, the contact part20has a substantially ring-shaped, flat contact carrier22and a terminal lug24which extends inwards from the contact carrier22in the same plane. Contact pieces26each having a contact tip28and resting pieces30with resting areas32, of which only some are identified, are arranged peripherally, equidistantly and alternately on the outer rim. The resting pieces each protrude to a lesser extent than the contact pieces. The contact part21shown inFIG. 5differs from that20shown inFIG. 6in that the contact pieces26and resting pieces30are not provided on one side but on both sides. Both the contact pieces26and the resting pieces30extend downwards on the outer rim, while the contact pieces26and the resting pieces30extend upwards on the inner rim.

InFIG. 1, the contact part20shown inFIG. 6is arranged in such a way that the contact pieces26and resting pieces30point upwards, i.e. towards the end-face contact layer14.

A contact part20shown inFIG. 6, but with downwards protruding contact pieces26and resting pieces30, is likewise arranged above the upper end-face contact layer12. This is electrically connected to a further terminal wire34by spot welding, crimping or soldering.

Furthermore, in each case one upper insulating cap36and one lower insulating cap38are positioned already from above and from below. In addition, a holding ring40has already been arranged on the upper insulating cap36.

InFIG. 2, the upper contact part20and the lower contact part20have already been pressed against the respective end-face contact layer12and14, to be precise in such a way that the contact tips28are pressed into the end-face contact layers12and14, respectively, and therefore an electrical connection is achieved. As can be seen from a comparison ofFIGS. 1 and 2, the insulating caps36and38inFIG. 2are not only positioned but are pushed completely onto the plastic film capacitor winding. The pushing-in process can be performed during installation of the plastic film capacitor winding10in a housing (not shown) by corresponding compressive force on the upper insulating cap36and the lower insulating cap38. In general, sheath insulation (not shown) is also provided.

FIGS. 3 and 4show the same for an encased electric three-phase capacitor. In order to produce an encased electric three-phase capacitor, three plastic film capacitor windings10are arranged in the form of a column one above the other. A contact part20shown inFIG. 6with downwardly protruding contact pieces26and resting pieces30is arranged above the upper end-face contact layer12of the uppermost plastic film capacitor winding10, and a contact part20as shown inFIG. 6with upwardly protruding contact pieces26and resting pieces30is arranged below the lower end-face contact layer14of the lowermost plastic film capacitor winding10. A contact part21as shown inFIG. 5is arranged between the uppermost plastic film capacitor winding10and the central plastic film capacitor winding10, and a contact part21as shown inFIG. 5is likewise arranged between the central plastic film capacitor winding10and the lowermost plastic film capacitor winding10. The uppermost contact part20is electrically connected to a terminal wire18by spot welding, crimping or soldering. Furthermore, a connecting wire42extends through the capacitor winding cores16of the three plastic film capacitor windings from the uppermost contact part20to the lowermost contact part20. The connecting wire42is electrically connected both to the uppermost contact part20and to the lowermost contact part20, in each case by means of spot welding, crimping or soldering.

A terminal wire20extends from the top through the hollow capacitor winding core16of the uppermost plastic film capacitor winding10to the contact part21arranged between the uppermost plastic film capacitor winding10and the central plastic film capacitor winding10and is electrically connected thereto by spot welding, crimping or soldering.

Finally, a terminal wire44extends from the top through the hollow capacitor winding core16of the uppermost plastic film capacitor winding10and the central plastic film capacitor winding10to the contact part21arranged between the central plastic film capacitor winding10and the lowermost plastic film capacitor winding10. The terminal wire44is electrically connected thereto by spot welding, crimping or soldering.

Precisely as in the embodiment shown inFIGS. 1 and 2, an upper insulating cap36and a lower insulating cap38are positioned at the top and at the bottom, respectively, wherein a holding ring40is also arranged on the upper insulating cap36. Likewise precisely as in the embodiment shown inFIGS. 1 and 2, the contact tips28can be pressed into the respective end-face contact layers12and14by the upper and lower insulating caps36and38being pushed further onto the plastic film capacitor winding10by corresponding compressive force for example during installation in a housing (not shown). In the two embodiments, the plastic film capacitor windings10and contact parts20can be held in position by the holding ring40or a holding bead and a permanent electrical connection can thus be ensured.

By virtue of the resting pieces30and the resting areas32, the penetration depth is limited during fitting in order to prevent damage to the plastic film.

The basic shape of the contact parts20and21can have very different geometry, wherein, owing to the round shape of the capacitor windings, a ring-shaped geometry appears to be particularly suitable, however.

The contact parts20and21can be stamped parts. Depending on the intended use, the contact pieces26can be bent only to one side or else to both sides from the stamped part. In the case of the two-sided embodiment, two contact layers (winding bridges) positioned together can be electrically connected to one another to form a winding column without any additional metal connection. Metal with good electrical conductivity, in particular brass or copper, is preferred as the base material for the contact parts. A tin plating is advantageous, but not absolutely necessary, for improved contact-making.

By virtue of the contacts disclosed above, the soldering operations which are time-consuming and difficult directly at the end-face contact layers (winding bridges) are no longer required. The size of the contact parts is dependent on the size and performance of the capacitor windings and the area of the end-face contact layers.

The features of the invention disclosed in the description above, in the drawings and in the claims can be essential both individually and in any desired combinations for implementing the invention in its various embodiments.

LIST OF REFERENCE SYMBOLS

10Plastic film capacitor winding

12,14End-face contact layers