DE102008050707B9 - Low-inductance, low-discharge, electrical housing feedthrough external connection for encapsulated electronic components - Google Patents

Abstract

Low-inductance, low-discharge, electrical housing feedthrough external connection for encapsulated electronic components, comprising a connection threaded bolt or an internally threaded connection socket (1; 10), the bolt or the bushing (1; 10) having an inner flange (12) relative to a housing leadthrough comprising an insulator body (3) slidable on the bolt or bush (1; 10), a gasket (5) acting between the flange (12) and the bushing, and means for mechanically fixing and clamping said assemblies a nut (2), wherein - the seal as a mushroom-shaped body (5) is formed, wherein the mushroom head (5.5) has a diameter greater than the housing passage and the mushroom foot (5.6) substantially corresponds to the housing passage diameter and the body (5 ) has a passage, so that this body (5) with respect to the Gehäusedurchf From the outside via bolt (1) or bushing (10) can be pushed on, - Furthermore, a hat-shaped thrust washer (7) is provided, which on the one hand the inner flange (12) at least ...

Description

The invention relates to a low-inductance, low-discharge, electrical housing feedthrough external connection for encapsulated electronic components, comprising a connection threaded bolt or a female threaded connector, the bolt or the socket having an inner flange relative to a housing passage, one on the bolt or the socket slidable or attachable insulator body, acting between the flange and the housing grommet seal and means for mechanically fixing and clamping of the aforementioned assemblies, designed as a nut, and an encapsulation of an electrical component with a low-inductance housing bushing external connection.

DC capacitors in prismatic housings, eg. B. for use in intermediate circuits of converters or filter circuits, belong to the prior art. In such capacitors prismatic steel or aluminum housing are usually provided which contain the capacitor winding package. The housings are gas-tight filled with resin. The aim of the connection connections is to obtain the lowest possible inductance and to ensure a high surge current resistance. It should be noted that, depending on the application and network conditions, RMS currents of up to 400 A can and must be controlled.

To keep the self-inductance of such capacitors low, special flat terminals are used. Reference is made in this regard to the products of the company Electronicon capacitors GmbH, Gera, product catalog DC capacitors series E56.XXX, 2008 edition.

As can be seen from the aforementioned product catalog, the housing feedthrough external connections for such encapsulated capacitors comprise a plastic insulator body with a ring structure, wherein the insulator body has a through-bore which accommodates and guides the actual conductive connection bolt. The connecting bolt may have an external thread, but also be socket-shaped with an internal thread.

In order to ensure the desired electrical insulation of the connecting bolt relative to the housing, an insulating spacer body and / or a cylinder-section-shaped seal is used, d. H. pushed onto the bolt. The aforementioned modules are then clamped by means of a nut and mechanically fixed. Due to the laminar layering of sealing disc and additional insulating support body with optionally cylindrical extension there is a risk that form part discharge sections due to the different dielectric constants. In addition, it can not be ensured during a retightening of the fastening means that the internal connection connections remain torque-free and thus free of damage.

In the above-mentioned prior art, therefore, both the sealing and the torque stabilization of the connecting element take place directly over the seal. This means that on the one hand the seal has to be soft enough to ensure good filling of the air gaps with the aim of a desired partial discharge resistance. On the other hand, the seal must also be mechanically stable enough to absorb the high forces due to the required torque resistance. A simultaneous optimization of both properties is not possible according to the prior art and there is no fixed mechanical stop for a dimensionally accurate installation.

From the US 5,926,357 A is a DC low-voltage miniature bushing for electrolytic capacitors, especially for miniature capacitors and their application in the medical field previously known. A given there spatial proximity of a housing and a feedthrough bolt and the multiple layering due to the two-part design of an electrical feedthrough seal in addition prohibit use at high alternating voltages. Furthermore, partial discharge effects can be expected even at very low voltage levels in this prior art due to the spatial conditions. The seal provided there is completely enclosed neither in the inner nor in the outer part of the implementation. Rather, the sealing material is cut, leaving air gaps, which are a source of the aforementioned unwanted partial discharges.

The US 2,666,805 A discloses an insulated connection terminal, e.g. B. applicable to electric motors or generators. The actual implementation consists of multi-layered parts together with gasket and an insulator block and dummy block. Such a layered embodiment is not free of partial discharge and therefore unsuitable for use as a connection terminal in low-inductance electrical housing feedthroughs, in particular for capacitors.

From the foregoing, it is therefore an object of the invention, a further developed low-inductance, low-discharge, electrical housing feedthrough external connection for encapsulated electronic components, eg. B. capacitors indicate which a simple final assembly, ie completion of prepared Housing installations, z. B. capacitor winding packages and this final assembly is possible from the outside, without positioning problems occur even in large-area arrangements with many feedthroughs and high tolerance requirements with respect to the terminal positioning, the functions sealing and mechanical stability are to be decoupled. In addition, it is an object of the invention to ensure that the necessary sealant or seals can also be replaced later and that the overall arrangement has a high external and internal electrical strength by aspiring large air and creepage distances.

The object of the invention is achieved by a low-inductance, low-discharge, electrical housing bushing external connection for encapsulated electronic components according to the combination of features according to claim 1 and a coupling according to claim 6, wherein the dependent claims comprise at least expedient refinements and developments.

In view of the prior art, it is therefore assumed that a housing bushing external connection, which has a connection threaded bolt or provided with an internal threaded connection socket, wherein the bolt or the socket has a relative to the housing passage inside or inner flange.

In addition, an insulator body which can be slid or placed onto the bolt or the bush is provided and a seal acting between the flange and the bushing is provided. Furthermore, means for mechanically fixing and clamping of the aforementioned assemblies are used. These means include a nut, here a ring nut.

According to the invention, the seal is designed as a voluminous, mushroom-head-shaped body, wherein the mushroom head has a diameter which is larger by a defined amount than the housing feedthrough. The mushroom foot substantially corresponds to the housing feedthrough diameter, but extends into the housing interior, i. H. the height dimension of the mushroom foot is substantially greater than the thickness of the encapsulation in the region of the housing feedthrough.

The seal as a mushroom-shaped, provided with a mushroom foot body has a preferably cylindrical passage in order to push the body relative to the housing feedthrough from the outside via the connecting threaded bolt or the socket.

Furthermore, according to the invention a hat-shaped thrust washer is provided, which at least partially surrounds the inner flange on the one hand and on the other hand, on the underside of the housing passage opening, the mushroom foot of the seal enclosing, is supported.

The pressure disk or the hat-shaped pressure body is centered and guided by a cylindrical portion of the bolt or bush, which is close to the inner flange, in order to ensure the desired exact positional position and easy assembly of the overall arrangement.

The insulator body has ausgestaltend on its remote from the housing passage side a recess for at least partially receiving the nut, wherein the nut is preferably formed as a ring nut. The recess may have a depth which corresponds to the thickness of the ring nut, so that this quasi finds its place in the insulator body quasi.

The hat-shaped thrust washer or the thus configured pressure body consists of an insulating material or has an insulation coating, wherein the outer contour of the thrust washer or the pressure body of an imaginary, extending into the housing interior extension of the lower contour of the insulator body corresponds.

The hat-shaped thrust washer may further ausgestaltend have a shape which is complementary to a non-annular or non-circular outer contour of the inner flange to thereby form an anti-rotation.

The insulator body has ausgestaltend pointing to the housing passage molding, which substantially corresponds to the contour of the mushroom head of the seal, wherein the inner surface of the hat-shaped thrust washer is adapted to the shape of the mushroom foot of the seal.

The seal, in turn, preferably consists of a flexible, elastic insulating material. With regard to the quasi-cavity between the shape of the insulator body and the shape of the pressure disk, the sealing body formed as mentioned has an excess, so that when screwing or clamping the overall arrangement, a corresponding surface pressure on the sealing body is effected with the result of a very close, quasi-gas-tight closure ,

Starting from the inner flange, an internal electrical connection section extending into the encapsulation of the electronic component is provided. This can z. B. be configured as a threaded portion which connects to the inner flange.

The inner flange may be formed as a key surface to make the corresponding inner terminal connection by screwing.

The invention will be explained below with reference to an embodiment and with the aid of figures.

Hereby show:

1 a sectional view through the inventive embodiment of a housing bushing outer terminal with a connecting threaded bolt and

2 a similar view, however, in the embodiment with a female connector having an internal thread.

In the case of the low-inductance, low-partial-discharge or partially discharge-free electrical housing feedthrough external connection according to the invention for encapsulated electronic components, the following is initially applicable 1 a connecting thread bolt 1 present, which serves with its threaded extension the external electrical connection.

Alternatively, it is as shown 2 possible, instead of the protruding threaded section the connection as a connection socket 10 execute, with the connector has a corresponding internal thread.

In another section, the bolt points 1 or the socket 10 an external thread 11 on.

This external thread 11 serves to accommodate a particular ring nut 2 , which is provided with a corresponding complementary internal thread.

The bolt 1 or the socket 10 have a respect to the housing feedthrough of the housing 4 inner flange 12 , This inner flange 12 can be designed as a mounting key surface.

Furthermore, an insulator body 3 present, having a through hole to the bolt 1 or the socket 10 take.

At the inner flange 12 closes a threaded section 13 to the internal electrical connection, z. B. the connection to a capacitor winding package is used.

The seal according to the invention 5 is now not designed as a conventional flat elastic sealing disc, but consists of a sealing body comprising a mushroom-shaped portion 5.5 and a mushroom-shaped section 5.6 ,

The mushroom-shaped section 5.5 has a diameter which is larger than the recognizable in the figure housing passage opening in the housing 4 , The diameter of the mushroom foot section 5.6 corresponds essentially to the housing feedthrough diameter. The seal 5 has a passage to push from the outside over the bolt 1 or the socket 10 to enable. So, after loosening the nut 2 and removing the insulator body 3 the seal is removed and easily replaced.

Furthermore, below the housing 4 , extending into the interior of the housing (not shown), a hat-shaped thrust washer 7 provided, on the one hand, the inner flange 12 at least partially surrounds and on the other hand on the underside of the housing passage opening, the mushroom foot section 5.6 enclosing the seal, supports.

The pressure disc 7 is doing by a, near the inner flange, cylindrical section 14 the bolt or the bush centered and guided.

The insulator body 3 has a recess on its side remote from the housing passage 15 for at least partial admission of the mother 2 on, where, as already mentioned, the mother can be formed as a ring nut and in this case the shape of the recess 15 the outer contour of the ring nut corresponds.

The hat-shaped pressure disc 7 consists of an insulating material or comprises an insulation coating, wherein the outer contour of the thrust washer 7 an imaginary, extending into the housing interior extension of the contour X of the insulator body 3 equivalent.

The hat-shaped pressure disc 7 has a shape that a non-annular or circular outer contour of the inner flange 12 is complementary, thereby forming an anti-rotation. So it will be when putting on the mother 2 acting torques caught and so do not get over the threaded section 13 on electrical internal fasteners.

The insulator body 3 has a view to the housing passage shaping 16 on, which is essentially the contour of the mushroom-shaped section 5.5 the seal 5 corresponds, wherein the inner surface of the hat-shaped pressure plate 7 to the shape of the mushroom foot section 5.6 the seal 5 is adjusted.

The proposed solution of a novel housing bushing external connection for electronic components, the final assembly and completion of prepared housing internals, z. B. capacitor winding packages, perform from the outside without positioning problems.

It results from the solution presented a high dimensional stability due to an exact cylindrical guide and height limit by the mother 2 , the insulator body 3 , the seal 5 in connection with the effect of the pressure disc 7 and contacting the insulator body 5 and the pressure disc 7 at the corresponding section of the housing 4 , Thus, the solution presented is particularly for gas-tight capacitors for low-inductive external sandwich interconnections ( 2 ) with high accuracy requirements.

Likewise, a high mechanical strength with the possibility of subsequent torque control and correction on the mother 2 possible without the risk of damaging an internal wiring on the section 13 consists.

As already mentioned, the seal can 5 be replaced later.

In addition, the chosen structure ensures high external and internal electrical strength through large clearances and creepage distances. Equally positive is the resulting partial discharge resistance due to a significantly increased distance between the active potential at the connection bolt 1 and the housing 4 and the consistent avoidance of air inclusions or flat, parallel layered Isolierstoffanordnungen between the individual potentials.

Ultimately, a high tightness is due to the generously dimensioned design of the sealing body 5 with area effect to the connection bolt 1 and the case 4 at a defined pressure and simultaneous spatial guidance and limitation of the sealing body 5 through the pressure disk 7 guaranteed.

In the solution according to the invention, the functions of sealing and mechanical stability with the help of the parts 3 . 5 . 7 and 12 decoupled from each other, whereby an optimization of the seal for the partial discharge resistance is achieved, without any disadvantages for the also desired mechanical stability. By a positive connection of the ribbed outer contour of the pressure plate 7 with the not shown in the figure, hardened potting z. B. in the form of a PUR or epoxy molding material and the above-mentioned anti-rotation between thrust washer 7 and flange 12 Can the while tightening the mother 2 or the outer terminal elements impressed torques are received harmless and there is at the same time a solid mechanical stop for a dimensionally accurate installation.

For the execution of the connecting bolt 10 and mother 2 according to 2 with internal thread is in principle also a reversal of the thread assembly according to the invention lying, ie it can be an internal thread in the mother 2 and a blind hole of larger diameter without thread in the connecting bolt 10 to be available.

Claims (7)

Low-inductance, low-discharge, electrical housing feedthrough external connection for encapsulated electronic components, comprising a connection threaded bolt or an internally threaded connection socket ( 1 ; 10 ), wherein the bolt or the bushing ( 1 ; 10 ) a relative to a housing passage inner flange ( 12 ), one on the bolt or the bush ( 1 ; 10 ) can be pushed or placed on insulator body ( 3 ), one between the flange ( 12 ) and the housing passage acting seal ( 5 ) as well as means for the mechanical fixing and clamping of the aforementioned assemblies, designed as a nut ( 2 ), wherein - the seal as a mushroom-shaped body ( 5 ), wherein the mushroom head ( 5.5 ) has a diameter larger than the housing passage and the mushroom foot ( 5.6 ) substantially corresponds to the housing passage diameter and the body ( 5 ) has a passage, so that this body ( 5 ) with respect to the housing passage from the outside via bolts ( 1 ) or socket ( 10 ), - further a hat-shaped thrust washer ( 7 ) is provided, which on the one hand the inner flange ( 12 ) at least partially surrounds and on the other hand at the bottom of the housing passage opening, the mushroom foot ( 5.6 ) of the seal ( 5 ), is supportable, wherein the pressure disk ( 7 ) of one, the inner flange ( 12 ), cylindrical section ( 14 ) of the bolt ( 1 ) or the socket ( 10 ) is centered and guided, - and the insulator body ( 3 ) on its side remote from the housing feedthrough a recess ( 15 ) for at least partially receiving the mother ( 2 ), wherein the nut ( 2 ) is designed as a ring nut. Low-inductance housing bushing external connection according to claim 1, characterized in that the hat-shaped pressure disk ( 7 ) consists of an insulating material or has an insulation coating, wherein the outer contour of the pressure plate ( 7 ) of the contour of the insulator body ( 3 ) corresponds. Low-inductance housing bushing external connection according to one of the preceding claims, characterized in that the hat-shaped pressure disk ( 7 ) has a shape which is a non-annular or non-circular outer contour of the inner flange ( 12 ) is complementary to form an anti-rotation. Low-inductance housing bushing external connection according to one of the preceding claims, characterized in that the insulator body ( 3 ) a housing for the implementation facing formation ( 16 ), which essentially corresponds to the contour of the mushroom head ( 5.5 ) of the seal ( 5 ), wherein the inner surface of the hat-shaped pressure plate ( 7 ) to the shape of the mushroom foot ( 5.6 ) of the seal ( 5 ) is adjusted. Low-inductance housing bushing external connection according to one of the preceding claims, characterized in that the seal ( 5 ) consists of a flexible insulating material. Encapsulation of an electrical component with a low-inductance housing bushing external connection according to one of the preceding claims 1 to 5, characterized in that starting from the inner flange ( 12 ) an internal electrical connection section extending into the encapsulation of the electrical component ( 13 ) is provided. Encapsulation according to claim 6, characterized in that the connection section ( 13 ) is in electrical and mechanical connection with a capacitor winding package.

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