DE3436898A1 - Foil-chip capacitor - Google Patents

Abstract

A foil-chip capacitor is described which is intended primarily for surface mounting by means of reflow soldering or wave-bath soldering and whose connecting elements are constructed as round wires which emerge from a sheath in the form of double connections, which round wires are partially pressed to form flat wire sections and have at least one essentially right-angled bend.

Description

The invention relates to a foil chin capacitor,

especially for surface mounting by reflow or wave soldering, consisting of one of metal and dielectric foils or of metallized Foil built-up capacitor body with electrically conductive on each end a covering fastened connection elements and a casing.

Foil-chip capacitors of this type are from DE-PS 31 34 617 known. The connection elements of these known film capacitors consist of single or donned webs soldered to the respective end-face connection layer, those at a distance from the capacitor body perpendicular to the connection layer on the end face are angled towards the capacitor body, each web at the bend point merges into a wide contact area.

Capacitors of this type are increasingly required for the automatic assembly or contacting are suitable and in the form of elements comparable to IC packages are present, which if present are flatter Contacts can be used as pluggable elements.

The object of the invention is to provide capacitors of the type defined at the outset Art to produce in a particularly economical way with high dimensional accuracy and thus also to enable automatic contact, with these capacitors also against the contacting occurring heat exposure must be insensitive and have optimal electrical values.

This object is achieved according to the invention in that the connecting elements designed as round wires emerging from the casing in the form of double connections are that the over the sheath protruding - ox wire sections to flat wire sections are pressed and that each flat wire section at least one substantially rectangular Has kink.

On the one hand, the use of round wires makes it special economic production made possible and on the other hand result surprising advantageous electrical properties. The envisaged covering represents an exact one Positioning of the connection elements securely, and after the formation of the envelope On the one hand, the flat wire sections produced enable automatic assembly analogous to IC housings and on the other hand protect the capacitor body from possible dangerous exposure to heat.

Particularly advantageous refinements of the invention are set out in the subclaims specified.

The invention is described below with reference to the drawings explained on the basis of exemplary embodiments; in the drawing shows: Figure 1 a Schematic representation of a capacitor body with round wire connection elements attached to the front before wrapping, Figure 2 is a schematic representation of a capacitor body with U-shaped bent connection elements, Figure 3 is a side view of the capacitor according to FIG. 2 after sheathing, FIG. 4 is a plan view of the capacitor according to FIG 2 after sheathing, FIG. 5 a schematic side view of a first embodiment a finished capacitor according to the invention suitable for automatic assembly, Figure 6 shows a second embodiment of a finished, for automatic assembly suitable capacitor according to the invention, Figure 7 shows a third embodiment a finished capacitor according to the invention suitable for automatic assembly, and FIG. 8 shows a schematic illustration to explain a particularly advantageous one Process for the manufacture of capacitors according to the invention.

Figure 1 shows schematically a capacitor body (1), e.g. made of aluminum and dielectric foils or metallized foils, in particular, can also be built up in a layered construction. This is on the front Capacitor grain (1) with connection layers (2) that preferred are applied by Schoopieren, provided. By using four wire connections, i.e. two wire connections (3) per surface, one can be in design, application and Particularly favorable chip design with regard to electrical values for metallized ones Foil capacitors can be achieved.

FIG. 2 shows one that essentially corresponds to the illustration in FIG View, but with U-shaped bent wire connections as connecting round wires (3) are used, and the narrow central part of the U-shaped connecting element with the schoopierten face of the condenser, which is preferably one metallized foil capacitor acts, is electrically connected, through Soldering or welding.

The opposite parallel lead out of the connecting wires (3) from the casing, which is also not yet shown in FIG. 2, it turns out with regard to assembly and electrical values are particularly advantageous.

The U-shaped connection element that each end face of the capacitor assigned, can be symmetrical, i.e. designed with legs of the same length, but it is also advantageous for some applications to have one leg shorter than to choose the other, especially half as long.

The side view according to FIG. 3 and the top view according to FIG. 4 show the capacitor explained with reference to FIG. 2 after a casing (4) has been attached. This envelope (4) has a cuboid shape and is preferably pressed around Casting around or implemented by installing the condenser grain in a cup. the Sheath consists in particular of Epoxy, polyester or silicone resin, in a flame-retardant setting.

Figure 5 shows a finished capacitor according to the invention in which the connecting round wires are pressed flat immediately after their exit from the sheath (4) are, so that flat wire sections (5) arise. These flat wire sections (5) run in the embodiment according to Figure 5 parallel to the side surfaces the cuboid casing, since in the area of the transition from the round wire section A 90 ° kink (6) is provided for flat wire cutting. The connecting wires are cut off in such a way that there is a maximum protrusion of 0.5 mm.

In the embodiment according to FIG. 6, the flat wire cuts are (5) substantially parallel to the end walls of the body (4) up to its lower Edge guided and there bent again at kinks (7) by 90 ° outwards.

In the embodiment according to FIG. 7, the free end regions are of the flat wire sections (5) are not bent outwards but inwards by about 90 ° and reach under the body (4) somewhat, the free end portion of the flat wire regions again runs approximately parallel to the underside of the capacitor body.

The capacitors described allow an extremely economical Manufacturing, provide exact dimensional accuracy and are ideal for automatic Suitable for assembly, whereby the interaction of round wire sections and flat wire sections in terms of production and with regard to the electrical values particularly has a favorable effect and also with regard to the thermal stress that occurs during soldering, due to the formation of thermal barriers, to an increase in functional reliability leads.

Figure 8 shows a preferred way of producing the invention Capacitors, a support form with frame elements (8) on both sides made of strip material is used, on which inwardly facing the U-shaped connecting wires (3) are welded are, with such a mutual spacing of the opposing Connecting wires that the capacitor grains are inserted and soldered or

can be welded, with a continuous manufacturing process is possible.

Claims (14)

Foil Chip Capacitor Claims: Foil Chi Capacitor, in particular for surface mounting by reflow or wave soldering, consisting of made of one made of metal and dielectric foils or of metallized foils Capacitor body with electrically conductive attached to a facing at each end Connection elements as well as a casing, thereby g e k e n n n z e i c h n e t that the connection elements (3) as in the form of double connections from the Wrapping (4) emerging round wires are formed that protrude beyond the sheath (4) Usually round wire sections are genresst to flat wire sections (5) and that each flat wire section (5) has at least one essentially right-angled bend (6,7). 2. Capacitor according to claim 1, characterized in that g e k e n n z e i c h n e t that the envelope (4) is cuboid and that at least a partial area of the flat wire sections (5) essentially parallel to and along a square surface is led. 3. Capacitor according to claim 1 or 2, characterized in that g e k e n n -z e i c h n e t that the round wires (3) immediately behind the exit point from the Sheath (4) are pressed flat starting. 4. Capacitor according to one of the preceding claims, characterized it is noted that the exit points of the connecting wires (3) are the same Polarity are offset from one another by 1800 (Figure 1). 5. Capacitor according to one of claims 1 to 3, characterized g e k e n n z e i c h n e t that the exit points of the connecting wires (3) of the same polarity are arranged side by side (Figure 4). 6. Capacitor according to one of the preceding claims, characterized in that g It is not noted that the vlaxed wire sections (3) after the exit point are bent out of the envelope (4) by 9o ° and the free ends are maximal around o protrude 5 mm over the casing (4). 7. Capacitor according to one of the preceding claims, characterized in that g It is not noted that the flat wire sections (5) along two times by 900 the auader-shaped envelope (4) are bent. 8. Capacitor according to one of the preceding claims, characterized it is not noted that the flat wire sections (5) once by 90 ° along the cuboid casing (4) and once by 180 ° away from the condenser body (1) are bent. 9. Capacitor according to one of the preceding claims, characterized it is noted that the capacitor grain (1) is essentially center-symmetrical is arranged in the casing (4). 10. Capacitor according to one of the preceding claims, characterized in that g e k e n n n n z e i c h n e t that with each end-face connection surface (2) the short Middle leg of a U-shaped bent connecting wire (3) is connected. 11. Capacitor according to claim lo, characterized in that g e k e n n -z e i c h n e t that the mutually parallel legs of the connecting wires (3) are different Own length. 12. Capacitor according to one of the preceding claims, characterized it is not indicated that molding compounds or casting compounds are used as the casing (4) made of polyester, epoxy or Silicone resin, especially in flame retardant Setting are used. 13. Capacitor according to one of the preceding claims, characterized in that g It is not noted that the connections (3) are made of material with low thermal conductivity, in particular made of galvanized nickel, nickel silver or steel. 14. Capacitor according to one of the preceding claims, characterized it is noted that the capacitor body (1) consists of a metallized Film capacitor consists of a layered construction.