The invention relates to an electrical high-current connection having a connector, a bushing and a fastening bolt. Furthermore, the invention relates to a method for coupling a high-current- conducting plug connection.

In high-voltage networks, high-voltage cables are frequently coupled to switching systems. For this purpose, the high-voltage cables are connected to a bushing of the switching system at cable lugs for example, by means of a screw connection for example, which are fastened to their conductor end. Connectors made of elastomer, inter alia, are used for the electrical insulation and shielding. The connectors are usually manufactured with an underdimension with respect to the bushings, so that the connector expands when it is pushed onto the bushing and the bushing is enclosed in an air-tight manner and with closed electrical interfaces. Therefore the user must push the connector with force onto the bushing during installation, while he makes and tightens the screw connection with the other hand. The forceful pushing-on during the tightening can lead to canting. As a result, conductive turnings or even particles may arise, which can lead to a breakdown of the product.

The object of the invention is therefore to provide a secure electrical high-current connection which is simple and safe to assemble.

The object is achieved by an electrical high-current connection having a bushing that has an electrically conductive contact surface arranged at an end face, wherein the bushing is provided with a bushing opening at the end face, having a connector that has a bushing socket for receiving the bushing in a plug-in direction, wherein the connector, in the plug-in direction, opposite the end face of the bushing is provided in the bushing socket with a contact body made of electrically conductive material and a fastening opening passing through the contact body, and having a fastening bolt which can be fastened at one end thereof in the bushing opening and the other end of which is provided with a bolt lock, wherein in the case of spaced-apart contact body in the plug-in direction of the electrically conductive contact surface, the bushing strikes against the bushing socket in the plug in direction and wherein the fastening bolt, which is in particular completely inserted into the fastening opening and fastened there, extends through the fastening opening with bolt lock projecting on the side of the contact body facing away from the bushing, before the bushing strikes against the bushing socket.

Furthermore, the object is achieved by a method for coupling a high-current-conducting plug connection, which comprises the following steps: - inserting and fastening the fastening bolt into a bushing opening at an end surface, provided with an electrically conductive contact surface, of the bushing; inserting the end face of the bushing in the plug-in direction into a bushing socket of the connector, at most until the bushing strikes the bushing socket, wherein contact surface and contact body are spaced apart from one another upon strike; and - plugging through the fastening bolt through a bushing opening of the contact body, wherein, when the fastening bolt is inserted in particular completely into the bushing opening and fastened there, a bolt lock of the fastening bolt projects onto the side of the contact body facing away from the contact surface.

As a result of the fact that the bolt lock projects on the side facing away from the contact body in the case of a fastening bolt in particular completely inserted into the bushing opening and fastened there, before the bushing strikes against the bushing socket, the connector can be laid down on the fastening bolt, without an axial force having to be applied, in order to avoid slippage of the connector. Thus the user has both hands free, in order to apply and tighten a nut, for example, to the bolt lock. A fastening bolt inserted and fastened in particular completely into the bushing opening means that the fastening bolt is inserted deeply enough into the bushing opening and fastened there, in order to be able to absorb the bending forces which act on the fastening bolt as a result of the connector being laid down, without being torn out of the bushing opening.

The solution according to the invention can be further improved by the following additional features, which in each case can be combined with each other as desired. According to a first advantageous configuration, the fastening opening of the bushing can be provided with an internal thread. Thus a fastening bolt can be screwed simply into the opening.

The bushing can also be called a duct. The bushing and/or the bushing socket can taper in the plug-in direction. In this way, in the case of a bushing socket manufactured with an underdimension, it is possible to push partially onto the bushing before the connector strikes against the bushing.

In a further advantageous configuration, the fastening bolt can be provided with an external thread. As a result, a simple screw connection of the fastening bolt is possible, in an internal thread of the bushing opening for example.

According to a further configuration, the fastening bolt can have an external thread which, when the fastening bolt is in particular completely inserted into the bushing opening and fastened there, is screwed in the bushing opening until it strikes. A fastening bolt inserted in particular completely into the bushing opening and fastened there can be, according to a further implementation, a fastening bolt screwed into the bushing opening by means of at least three thread turns. As a result, the fastening bolt is screwed into the bushing opening in a standard manner, and cannot be ripped out of the bushing opening by pulling forces which arise e.g. when a tightening element, such as e.g. a nut, is actuated. The electrically conductive contact body can be, for example, a cable lug, the fastening opening of which is arranged coaxial to the fastening bolt.

According to a further advantageous configuration, at least the bolt lock can have an external thread. A tightening element, such as e.g. a nut or a coupling bolt, for coupling to a further electrically conductive contact body, can be attached to the external thread. By actuating the tightening element, the contact body and the electrically conductive contact surface of the bushing can be moved towards each other, when the bushing strikes against the bushing socket and the fastening bolt is received and fastened in the bushing opening. In particular the contact body and the contact surface of the bushing can be moved towards each other by actuating the tightening element while overcoming the stop. In order to be able to receive the tightening elements, such as e.g. a nut or a coupling bolt, the bolt lock projecting from the side of the contact body facing away from the bushing can be at least long enough for the external thread to reach into the nut or the coupling bolt, respectively. Here, the bolt lock can have at least the length of a thread turn, in particular for the attachment of a nut.

Preferably, the bolt lock can have at least the length of the thread diameter. In order to achieve contacting of the electrically conductive contact surface with the electrically conductive contact body, the fastening bolt can be provided with an external thread extending from the bolt lock counter to the plug-in direction. In this case, the external thread can be longer than the spacing between the electrically conductive contact body and the electrically conductive contact surface when the bushing strikes against the bushing socket.

In order to avoid wear of the electrically conductive contact body by abrasion on the fastening bolt, the fastening bolt can have a thread-free section, which is preferably as long as the fastening opening of the contact body, which is arranged in the fastening opening, when the contact surface strikes the contact body. If additional elements are used in the screw lock, such as washers for example, the thread-free section can be designed in a correspondingly elongated manner. In the assembled state, friction may occur between fastening bolt and contact body, for example as a result of vibrations. If the contact body rests upon a gearing, the friction would lead to a higher degree of wear.

According to a further advantageous configuration, an electrically insulating closure plug can be arranged at the end of the fastening bolt facing away from the bushing. The closure plug can have an internal thread, for example, which can be screwed onto an external thread of the fastening bolt.

In order to simplify the attachment, for example, of a washer or a nut to the bolt lock, the bolt lock can have a rising incline and/or a rounding. By means of the rising incline and/or rounding, attachment at an angle is possible, as a result of which the assembly is simplified in particular when the space proportions are narrowed, e.g. connectors of smaller constructional form with lower voltage classes.

In a further implementation, the external thread can be at least as long as the sum of the spacing between contact body and contact surface, when the bushing strikes against the bushing socket, the material thickness of the contact body and a thread pitch, preferably multiple thread pitches or even double the diameter of the external thread. In particular, in this configuration the external thread can extend from one end of the bolt lock to the opposite end.

According to a further implementation, the external thread can be at least as long as the sum of the spacing between contact body and contact surface, when the bushing strikes against the bushing socket, the material thickness of the contact body and a thread pitch, preferably multiple thread pitches or even the external thread diameter. As a result, it is ensured that contact surface and contact body are in contact by way of complete actuation of the tightening element. The external thread here can preferably extend as far as the end of the fastening bolt facing away from the bushing.

According to a further configuration, the fastening bolt can have a waist. The diameter of the waist can be reduced in such a way that, when the thread lock is actuated, effective stretching of the fastening bolt takes place, which gives additional security against release or too strong a contact force of the contact body at the electrically conductive contact surface.

According to a further advantageous configuration, at least a fifth of the length of the fastening bolt can be located in the bushing opening, when the fastening bolt is fastened there. As a result, the fastening bolt is inserted sufficiently deeply into the bushing opening, so that there is no damage to the fastening bolt or the bushing when the contact body of the connector rests upon the fastening bolt, and the fastening bolt is loaded with the transverse force on a lever arm.

In order to simplify the fastening of the fastening bolt in the bushing opening, the fastening bolt can be inserted into the bushing opening and fastened there, before the bushing is inserted into the bushing socket of the connector. As a result, the space for the assembly of the fastening bolt is not limited by the space proportions in the connector.

For the insertion of the bushing into the bushing socket, the bushing can be held stationary, while the connector with the bushing socket to the front is moved counter to the plug-in direction towards the bushing, wherein the bushing socket is positioned coaxial to the bushing.

So that contact surface and contact body can move towards each other, the fastening bolt, at its bolt lock projecting through the fastening opening at the side of the contact body facing away from the bushing, can be provided with a tightening element and actuated, when the fastening bolt is inserted into the connector opening and fastened there.

The invention is described in greater detail below by way of example on the basis of possible embodiments with reference to the enclosed drawings. The combinations of features depicted in the case of these embodiments only serve the purpose of illustration. Individual features can also be omitted in accordance with their advantages described above if the advantage of this feature is not significant in specific applications.

In the drawings: Fig. 1 shows a schematic sectional view of an electrical high-current connection according to the invention at the point at which the connector, with its bushing socket, strikes against the bushing; and

Fig. 2 shows a schematic sectional view of the electrical high-current connection depicted in Fig. 1 at the point at which the contact surface strikes the contact body of the bushing; and

Fig. 3 shows a schematic sectional view of a further fastening bolt according to the invention.

A schematic sectional view of an electrical high-current connection 1 according to the invention is depicted in Fig. 1 and Fig. 2.

The high-current connection 1 has a bushing 2, a connector 4 and a fastening bolt 6. The bushing 2 has an electrically insulating housing 8, which tapers in the plug-in direction E, which is directed parallel to the longitudinal axis L of the bushing 2 to the connector 4. A circular-cylindrical through-hole 10 passes through the housing 8, which through-hole is arranged coaxial to the housing 8. In the through-hole 10, an electrically conductive body 12 is inserted which projects out of the housing 8 at the end surface 14 facing the connector 4, and has an electrically conductive contact surface 16, which is arranged perpendicular to the longitudinal axis L.

The electrically conductive body 12 has a bushing opening 18 coaxial to the bushing 2, which bushing opening extends from the electrically conductive contact surface 16 counter to the plug-in direction E and is provided with an internal thread 20.

The connector 4 has a substantially symmetrical T-shaped base body 22, in the stem 24 of which a high-voltage / high-current cable 26 is arranged with a cable lug 28. The cable lug 28 is passed through by a fastening opening 30. The cable lug 28 protrudes into the horizontal region 32 of the base body 22, so that the fastening opening 30 is arranged coaxial to the bushing opening 18.

The cable lug 28 is electrically conductive and serves as an electrically conductive contact body 34, with which the electrically conductive contact surface 16 is to be brought into contact. The connector 4 has, at its arm 36 facing the bushing 2, a bushing socket 38 which runs from the end surface 40 as far as the contact body 34 and tapers in the plug-in direction from the end surface 40 as far as the contact body 34, analogously to the housing 8 of the bushing 2. The bushing socket 38, the bushing 2 and the fastening opening 30 are arranged coaxial to each other.

The housing 8 of the bushing 2 has an overdimension with respect to the bushing socket 38, so that the bushing 2 can be only partially received by the bushing socket 38, before the housing 8 of the bushing 2 strikes against the bushing socket 38. The high-current connection 1, at the point at which the housing 8 strikes against the bushing socket 38, is depicted in Fig. 1.

At the point depicted in Fig. 1, the electrically conductive contact surface 16 is spaced apart from the side 39 of the contact body 34 facing the bushing 2 by the spacing 41.

By means of the overdimension 37, the connector housing is widened when the connector 4 is pushed forcefully onto the bushing 2, so that the housing 8 is enclosed by the connector 4 in a manner free from air and with a radial contact pressure.

From its bushing-facing end 42, the fastening bolt 6 is provided with an external thread 44, with which it is screwed into the internal thread 20 of the bushing opening 18.

The fastening bolt 6 has a bolt lock 46, which projects by the length 50 out of the fastening opening 30 at the side 48 of the contact body 34 facing away from the bushing. The bolt lock 46 has a rising incline 54 at its outer edge 51 at the end 52 facing away from the bushing.

At the end 52 facing away from the bushing, the fastening bolt 6 is provided with a screw head drive 56 in the form of a hexagon socket 57, which is arranged coaxial to the fastening bolt 6. By means of the screw head drive 56, the fastening bolt 6 can be screwed simply into and onto the bushing opening 18. The bolt lock 46 is provided with an external thread 58, which extends from the rising incline 54 counter to the plug-in direction E as far as the end of the bolt lock 46 facing the contact body 34.

The fastening bolt 6 is provided with a further external thread 60, which connects to the external thread 58 and extends counter to the plug-in direction E by the length 62. The length 62, in this configuration, is at least as long as the spacing 41.

Between the external thread 60 and the external thread 44 screwed into the fastening opening 18, the fastening bolt 6 has a thread-free supporting section 64 with the length 66, which abuts both external threads 44, 60. The length 66, in this configuration, is at most as long as the fastening opening 30.

In the point shown in Fig. 1, the connector 4 lies on the fastening bolt 6 and the user has both hands free, in order to attach and tighten a tightening element 71, for example in the form of a nut 72 or a coupling bolt (not shown) onto the bolt lock 46.

In Fig. 2 the electrical high-current connection depicted in Fig. 1 is shown in the tightened state.

The length 50 of the bolt lock 46 is sufficiently long to attach a washer 70 and a nut 72 on the fastening bolt 6. By actuating the nut 72, the fastening bolt 6 is drawn by the spacing 41 with a high axial force in the plug-in direction E through the fastening opening 30 out of the side of the electrically conductive contact body 34 facing away from the bushing. As a result, the connector 4 is moved further counter to the plug direction E, until the electrically conductive contact surface 16 strikes the electrically conductive contact body 34.

From the arm 74 facing away from the bushing 2, which arm has an assembly opening 76 designed analogously to the bushing socket 38, an electrically insulating closure plug 78 or a coupling bolt (not shown), for example, can be attached to the fastening bolt 6 using a thread receptacle 80. Since the fastening bolt 6 projects from the contact body 34 deeply into the assembly opening 76 in the plug-in direction E, the closure plug 78 or the coupling bolt does not have to be inserted deeply counter to the plug-in direction E into the assembly opening 76, until the external thread 58 of the bolt lock 46 reaches into the thread receptacle 80. Thus the risk of canting is reduced and in turn the assembly forces to be applied manually are reduced.

According to the method according to the invention, the fastening bolt 6 is screwed into the bushing opening 18. The connector 4 is moved towards the bushing in the direction of the end surface 14 counter to the plug-in direction E until the bushing 2 strikes the bushing socket 38 and the fastening bolt 6 is plugged through the fastening opening 38 of the contact body 34, wherein the bolt lock 46 projects through the fastening opening 30 on the side 48 facing away from the bushing 2.

A nut 72, for example, can be attached to the bolt lock 46, which nut is screwed tightly. By means of the tightening, the connector 4 is pushed counter to the plug-in direction E onto the bushing 2 until the contact surface 16 strikes the contact body 34. The fastening bolt 6 depicted in Fig. 3 has, between the front external thread 44 and the bolt lock 46, a thread-free section 47 which has a smaller diameter than the front thread region 44. The passage from the front thread to the thread-free section 47 is formed by a chamfer. The thread-free section 47 extends in the longitudinal direction L as far as the bolt lock 46. The diameter of the thread-free region can be reduced in such a way that, when the thread lock is actuated, effective stretching of the fastening bolt 6 takes place, which gives additional security against release or too great a loss of the contact force of the contact body 34 at the electrically conductive contact surface. The thread- free section 47 is optional and can be omitted in other embodiments of the fastening bolt 6 as in Figs 1 and 2 for example.

Reference symbols high-current connection

bushing

connector

fastening bolt

housing

through-hole

electrically conductive body

end surface

electrically conductive contact surface

bushing opening

internal thread

T-shaped base body

stem

high-current/high-voltage cable

cable lug

fastening opening

horizontal region

electrically conductive contact body

arm

overdimension

bushing socket

side of the contact body facing the bushing end surface

spacing

end

external thread

bolt lock

thread-free section

side of the contact body facing away from the bushing length of the bolt lock

outer edge

end facing away from the bushing

rising incline

screw head drive

hexagon socket

external thread

external thread

length of the external thread

supporting section

length of the supporting section

washer

nut

arm

assembly opening

closure plug

thread receptacle