Abstract:
A solderless coaxial feedthrough component that has a metallic knit fabric contact element made of a mesh fabric inserted between a pressure element and a contact surface of the component.

Description:
TECHNICAL FIELD 
     The present invention concerns coaxial feedthrough components, such as coaxial feedthrough capacitors or coaxial feedthrough filters. 
     BACKGROUND 
     Until now, soft-solder connections or soldered-on contact elements have been used in coaxial feedthrough components, such as feedthrough capacitors or feedthrough filters, in order to electrically connect external electrodes of the component with the winding, for example, in the case of a feedthrough capacitor. Such soft-solder connections or soldered-on contact elements do, of course, provide for a good electrical connection between external electrodes and the winding. However, they have the disadvantage that considerable heat is produced during the soldering process, which has a damaging effect on temperature sensitive synthetic capacitor windings. Also, the specifications of radiofrequency tight contacts of the material are often difficult to realize with soft-solder connections or soldered-on contact elements which require a certain accessibility for tools. 
     SUMMARY 
     In one aspect, the invention is directed to a solderless coaxial feedthrough component that has a metallic knit fabric contact element (also referred to as mesh fabric) is inserted between a pressure element and the contact surface. The metallic knit fabric contact element is mechanically braced against a contact surface of components, for example, a capacitor winding, by means of a pressure element such that a reliable electrical contact is produced by means of this metallic knit fabric contact element between, for example, the capacitor winding and an electrode. 
     For this metallic knit fabric, a tin-plated or nickel-plated copper wire or another wire with good electrical conductivity is advantageously used. The feedthrough component may preferably be a coaxial feedthrough capacitor or a coaxial feedthrough filter. 
     The present invention can, consequently, provide a solderless coaxial feedthrough component with which it is possible to do without soft-solder connections or soldered-on contact elements and yet enables reliable, radio frequency tight contact of temperature sensitive components. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is explained in detail in the following with reference to the drawings. 
     FIG. 1 depicts a sectional view through a coaxial feedthrough capacitor according to a first exemplary embodiment of the invention. 
     FIGS. 2 a  and  2   b  depict sectional views through a coaxial feedthrough filter according to a second exemplary embodiment of the present invention in two different variants. 
     FIG. 3 depicts a sectional view of a feedthrough filter with a socket housing according to another exemplary embodiment of the invention. 
     FIG. 4 depicts a sectional view of a feedthrough filter with a tubular housing according to another exemplary embodiment of the invention. 
     FIG. 5 depicts a sectional view of a feedthrough filter with a flange housing threaded at both ends according to another exemplary embodiment of the invention. 
     FIG. 6 depicts a sectional view of the feedthrough filter with a tubular housing threaded at one end according to another exemplary embodiment of the invention. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 depicts a coaxial feedthrough capacitor in which a synthetic capacitor winding  1  is provided as a feedthrough element through an insulating sheath or an inner tube on a threaded bolt  3 . Between the synthetic capacitor winding  1  and a contact disk  4  on one side and between the synthetic capacitor winding  1  and a housing base  5  on the other side, a mesh fabric  6  made, for example, of copper is arranged in each case. These mesh fabrics  6  are braced between the synthetic capacitor winding  1  and the contact disk  4  and between the synthetic capacitor winding  1  and the housing base  5 , respectively, by the tightening of screws on the threaded bolt  3 . The capacitor winding  1  and its contact are then finally also surrounded by a housing  7  with the housing base  5 , which provides for a radiofrequency tight seal. 
     In this manner, a solderless, gentle, concentric, radiofrequency tight contact of the temperature sensitive synthetic capacitor winding  1  is obtained. 
     FIG. 2 a  depicts, as another exemplary embodiment of the solderless coaxial feedthrough element according to the invention, a sectional view through a coaxial feedthrough filter with inductive components  9  and capacitor windings  10  provided in a contact cup  8 , which are in contact via mesh fabrics  6  analogously as in the exemplary embodiment of FIG.  1 . These mesh fabrics  6  are braced against the capacitor windings  10  by screw-tightening a housing case  11 , which is screwed with a housing connector  12 . The housing potential is applied via the “outer” mesh fabrics  6  in FIG. 2 a , whereas the two “central” mesh fabrics  6  are each acted upon by the bolt potential via the contact cup  8 . 
     An insulating part  25  can possibly be provided between the two end parts of the contact cup  8  connected by the “central” mesh fabrics  6 , as depicted in FIG. 2 b . This insulating part  25  is used for electrical isolation. Here, for clarity, the left half of the contact cup  8  is depicted in bold. The bolt potential A is carried via this contact cup  8  and the mesh fabric  6 , whereas the housing potential B is applied on the left end in FIG. 2 b  via a contact disk  26  and the mesh fabric  6 . The winding packs are also braced in the housing by the contact disk  26  or the contact cup. 
     FIG. 3 depicts a feedthrough filter with a socket housing  13 , into which the complete assembly is screwed. This includes, in particular, the tubular core  14 , windings  10 , threaded housing contacts  15 , and insulating cap  16 , mesh fabrics  6 , and bolt contacts  17 . The housing contact  15  is in contact with a first winding potential, whereas the bolt contact  17  is provided against a second winding potential. The entire arrangement is installed moisture-tight in the socket housing  13  by means of a filling compound  18  and an adhesive coating  19 . In this exemplary embodiment as well, the mesh fabrics  6  are pressed against the respective contact surfaces of the winding  10  such that a reliable solderless contact is provided. 
     In the exemplary embodiment of FIG. 4, which also depicts an assembly  20  completely screwed into a housing (bolts, cores, windings, and contact disks) with a housing contact  15 , windings  10 , and filling compounds  18 , mesh fabrics  6  also lie between contact and/or pressure elements or contact disks  21  and the windings  10  such that a reliable contact of the windings  10  with the pressure elements  21  is provided via the mesh fabrics  6 . The same is true for the mesh fabrics  6  which are provided between the windings  10  and the housing contacts  15 . 
     The exemplary embodiments of FIGS. 3 and 4 thus depict a screwed-in, mesh-contacted assembly  20  with one winding side each against a bolt potential, while simultaneously the two other winding sides are applied to housing potential. This is a completely solderless design in which the contact is made solely via the mesh fabrics  6 . 
     In contrast to FIGS. 3 and 4, FIGS. 5 and 6 depict two other exemplary embodiments of the invention in which identical connection elements are connected with a choke  22  to bolt potential, while the contact of coils  10  is again made via mesh fabrics  6 . Connection elements  23  to bolt potential are guided to the choke  22  via bolt contacts  24 . Housing contacts  15  are against the mesh fabrics  6 . 
     FIG. 5 depicts a flange housing threaded on both ends whereas a tubular housing threaded on one end is depicted in FIG.  6 . Both housings are sealed on both ends by a filling compound  18 .