SWITCHING DEVICE FOR CONDUCTING HIGH CONTINUOUS CURRENTS AND VERY HIGH SHORT-CIRCUIT CURRENTS

Description

[0001] The present invention relates to a switching device for conducting high continuous currents and very high short-circuit currents.

[0002] DE 66 08 223 U already discloses a contact arrangement for high continuous current loads with continuous currents of up to 2000 A and above. The contact arrangement comprises a stationary contact piece and a cylindrical switching pin. The stationary contact piece is movably mounted on a contact housing and connected to an element that heats up and expands or contracts when current flows through the contact arrangement, thereby either shifting, rotating, or tilting the stationary contact piece from its rest position. During this movement of the stationary contact piece, sliding occurs between the contacting contact surfaces, destroying an oxide film that impedes current transfer and reducing the contact resistance.

[0003] US 4,039,786 shows an ultrafast switch with a pin- or rod-shaped movable contact arm. The contact arm is movably guided in a tubular guide. The contact arm is movable by means of a drive rod connected to a relay and can be engaged with a fixed contact. The fixed contact is sleeve-shaped and has, at its end facing the contact arm, a plurality of parallel flexible fingers in which a rounded end of the contact arm can be received. The tubular guide is connected to an external connecting cable by means of a metallic plate, and the fixed contact is connected to an external clamp.

[0004] DE 718 554 A discloses a gas-insulated switchgear or an electrical switch with arc quenching by a flowing pressure medium. The switch comprises a movable contact configured as a pin, which can be engaged with a fixed contact. Furthermore, the movable contact is guided in an intermediate contact and connected to a common contact. In the closed position of the switch, the movable contact extends through the intermediate contact and is accommodated in the fixed contact. When the switch is open, the movable contact is retracted and guided only in the common contact.

[0005] EP 2 525 455 A1 describes a gas-insulated switchgear with a bus-integrated disconnector. The bus-integrated disconnector comprises a pin-shaped movable contact guided in a movable lateral contact section. The movable contact can be moved via a lever element and brought into engagement with a fixed lateral contact section. This represents an electrically connected or closed state. The movable contact can be withdrawn from the fixed lateral contact section, leaving the disconnector in an electrically disconnected state.

[0006] US 2016 / 0035501 A1 also discloses a gas-insulated power switching device comprising a fixed electrode and a movable electrode arranged opposite each other in a container filled with insulating gas; and a rod-shaped movable conductor electrically connecting the fixed electrode and the movable electrode. The fixed electrode and the movable electrode have a contactor through which current flows to the movable conductor. The fixed electrode and the movable electrode have annular sliding elements, the annular sliding elements being arranged on both sides of the contactor.

[0007] It is well known that switching devices can exhibit insufficient short-circuit resistance. After a short-circuit event, such devices are often destroyed and thus unusable, and must be replaced.

[0008] It is therefore the object of the present invention to provide a switching device which avoids the problems known from the prior art and which can carry high continuous currents and even higher short-time currents without welding, in particular in the undisconnected, i.e. in the contacted state.

[0009] The problem is solved by the features of independent claim 1. Accordingly, in a switching device for conducting high continuous currents and very high short-circuit currents, the problem is solved according to the invention if the switching device has at least two contact points, each contact point comprising a movable contact and a fixed contact, one of the contacts of each contact point is formed in a socket and the other contact of each contact point is formed on a pin that can be received in the socket, and the movable contacts of the two contact points are formed as a common component, one of the two contacts having a ribbing on at least one of the contact points, so that a plurality of contact points is defined at the contact point, the ribbing is formed as a separate component in the form of contact lamellas,which is arranged at the corresponding contact of each contact point and the contact lamellae are designed as a high-current contact strip, which comprises a resilient carrier strip with two edge webs and a plurality of contact webs extending transversely to the edge webs and connected to the edge webs, wherein contact pieces are riveted onto the contact webs.

[0010] Thanks to the solution according to the invention, the switching device can carry high continuous currents and even higher short-term currents in the contacted state without welding of the contacts at the contact points. At the same time, only low actuation forces are required.

[0011] In this case, high continuous currents mean operating currents of up to 1000A. High or even higher short-time currents are in the range of up to 30kA. The fact that the contact points are designed as plug-in contacts, with each contact point comprising a socket and a pin that can be accommodated in the socket, and thus contact is present over the entire circumference of the pin and the socket that accommodates the pin, ensures that the electromagnetic repulsion forces that occur at high currents, for example short-circuit currents, do not lead to the contacts opening. Flutter effects that can lead to the contacts welding together are also avoided. The short-circuit strength of the switching device is increased, and the conduction of high continuous currents is ensured.Because one of the two contacts has a knurling on at least one of the contact points, the contact resistance is reduced and welding of the contact points is prevented. This enables the high continuous currents of up to 1000A and short-circuit currents of up to 30kA to be carried safely. This can be achieved in a simple design by constructing the knurling as a separate component in the form of contact blades, which is arranged on the corresponding contact at each contact point. The contact blades are preferably designed as an annular band or sleeve, i.e. as a high-current contact band, which can be easily pushed onto the pin or inserted into the socket. This enables a simple design, as the spring force is geometrically contained in the annularly arranged contact blades.

[0012] Preferably, the sockets and the at least one pin are aligned coaxially with each other. In a simple embodiment, the sockets and the at least one pin are cylindrical. This allows for easy mating of the contacts. However, other cross-sectional shapes of the socket and pin are of course possible, as long as easy mating and pulling apart, i.e., closing and opening, of the contact points is possible.

[0013] Advantageous embodiments of the present invention are the subject of the subclaims.

[0014] In a preferred embodiment of the present invention, the fixed contact of each of the at least two contact points can be formed in a respective socket, and the movable contacts of the at least two contact points can be formed on a common pin. Thus, during switching, the common pin is moved into or out of the sockets. This allows for a simple and stable design.

[0015] In particular, it is then also possible to provide at least a third contact point, which comprises a fixed contact formed as a socket and a movable contact, with the movable contact of the third contact point also being formed on the common pin. This allows for simple interconnection of at least three circuits.

[0016] According to another particularly preferred embodiment of the present invention, the pin can be accommodated in at least one of the sockets in each switching position. In the open position, the pin is then accommodated in at least one socket, and in a closed position, in at least two sockets. This achieves increased stability.

[0017] According to another particularly preferred embodiment of the present invention, the carrier strip is made of spring steel, and the contact pieces are made of copper. The carrier strip, made of spring steel, preferably stainless spring steel, exhibits high mechanical strength and excellent relaxation resistance, thus generating the mechanical strength and contact force. The contact pieces, made of highly conductive copper, ensure a high current-carrying capacity.

[0018] According to yet another embodiment, one of the two contacts can have two serrations arranged side by side at at least one of the contact points in the longitudinal direction of the socket and the pin. This parallel connection, i.e., the arrangement of several serrated areas next to one another, can further increase the current-carrying capacity of the switching device.

[0019] In order to increase the stability of the switching device, the pin can be provided with a central bore extending in the longitudinal direction of the pin, which engages with a centering bolt.

[0020] A further increase in the stability of the switching device can be achieved by enclosing each of the sockets in a solid block.

[0021] According to yet another embodiment, each of the solid blocks can be electrically connected to a connecting terminal. This allows for easy connection.

[0022] In order to enable a safe and stable guidance of the at least one movable pin, it can be provided that the pin is movable by means of at least one cylinder, preferably by means of two cylinders.

[0023] To enable a wide range of applications, the switching device can be designed as a normally open contact, a normally closed contact, or a changeover contact. This is made possible by various designs of the switching axis.

[0024] According to another particularly preferred embodiment of the present invention, the switching device is designed as a manual disconnect switch. The switching device is preferably designed as a manual disconnect switch for the safe, galvanic isolation of the battery / voltage source and the load during maintenance on battery-powered trains. In the operating state, i.e., in the closed state, the manual disconnect switch can carry all currents that occur, i.e., operating currents up to 1000A and short-time currents of 30kA.

[0025] An embodiment of the present invention is explained in more detail below with reference to the drawings. Fig. 1 an inventive switching device in exploded view; Fig. 2 the switching device according to the invention Fig. 1 in contacted state in perspective view; Fig. 3 the switching device according to the invention Fig. 1 in the separated state in perspective view; Fig. 4 a fixed contact of the switching device according to the invention Fig. 1 in exploded view; and Fig. 5 a movable contact of the switching device according to the invention Fig. 1 in exploded view.

[0026] In the following explanations, identical parts are designated by identical reference numerals. Where a figure contains reference numerals that are not further explained in the corresponding figure description, reference is made to preceding or subsequent figure descriptions.

[0027] Fig. 1 shows an exploded view of a switching device 1 according to the invention. The switching device 1 comprises a housing 2 with two side walls 3, 4, two end walls 5, 6, a base plate 7 and a cover 8. Two contact points 9, 10 are formed in the housing 2. Each of the two contact points 9, 10 comprises a movable contact 11 and a fixed contact 12. In the Fig. 1 In the embodiment shown, the two fixed contacts 12 are formed as or in a socket 13. The sockets 13 are cylindrical. Each of the sockets 13 is accommodated in a solid block 15. The blocks 15 are each electrically connected to a connection terminal 16. In the embodiment shown in Fig. 1 A slot 17 is formed in the rear side wall 3, through which one of the connecting terminals 16 is led outwards. Likewise, a further slot 18 is formed in the cover 8, through which the second of the connecting terminals 16 is led outwards.

[0028] The movable contacts 12 are formed on a pin 14 that can be received in the sockets 13. The pin 14 is also cylindrical and designed so that it can be inserted into and withdrawn from the sockets 13. The sockets 13 and the pin 14 are thus arranged coaxially with one another. In order to be able to move the pin 14 relative to the sockets 13—and thus open and close the contact points 9, 10—the pin 14 is movably guided by two cylinders 19 that are slidably mounted on one of the end walls 5 of the switching device 1. The two cylinders 19 are connected to a switching mechanism 21. The cylinders 19 are moved via this switching mechanism 21 and transmit the switching movement to the movable pin 14 with the movable contacts 11 formed thereon.

[0029] A centering bolt 20 is attached to the other end face 6 of the switching device 1. The centering bolt 20 is also coaxial with the bushings 13 and the pin 14. The pin 14 has a central longitudinal bore in which the centering bolt 20 is received, thus contributing to the secure guidance of the pin 14.

[0030] Fig. 2 shows a perspective view of the switching device 1 in the contacted state. The switching mechanism 21 is in the retracted position. This means that the cylinders 19 have been retracted as far as they can into the housing 2 of the switching device 1 and have brought the movable pin 14, or the two movable contacts 11 formed thereon, into engagement with both sockets 13, which form fixed contacts 12. The movable pin 14 is therefore engaged with both sockets 13, both contact points 9, 10 are closed, and the switching device 1 is in the operating state. Due to the design of the contact points 9, 10, which is described in more detail below, all currents that occur can be conducted, i.e. operating currents up to 1000 A and short-time currents of up to 30 kA.

[0031] Fig. 3 shows a top view of the switching device 1 in the disconnected state in perspective. In the disconnected state, the switching mechanism 21 is in the maximum extended position. This means that the cylinders 19 are maximally extended from the housing 2 of the switching device 1. The movable pin 14 is thus out of one of the bushings 13, in Fig. 3 shown on the left. This opens the contact point 10. At the other contact point 9, the movable pin 14 is still engaged with the socket 13. In Fig. 3 The centering bolt 20, on which the movable pin 14 is guided, can now also be seen.

[0032] Fig. 4 shows an exploded view of a detail of the switching device 1 from Fig. 1 , namely the design or arrangement of the fixed contacts 12 in the switching device 1. The arrangement of the fixed contacts 12 at both contact points 9, 10 is identical, but rotated by 90° to each other in the switching device 1. The fastening of each of the fixed contacts 12 comprises a solid block 15 in which a central bore 22 is formed. One of the sockets 13 is received in each of the central bore 22. The sockets 13 are held captively in the solid blocks 15 via the connecting terminals 16 and a holding plate 23. The solid block 15, the holding plate 23 and the connecting terminals 16 are preferably connected to one another via fastening means such as, for example, the Fig. 4 screws 24 shown.

[0033] Each of the sockets 13 has a ridge 26 on its inner side 25, i.e., the side that comes into contact with the movable pin 14 and on which the respective fixed contact 12 is formed. The ridge creates a plurality of defined contact points at each of the contact points 9, 10. The current to be transmitted is thus distributed across a plurality of contact points, so that at each contact point, only a portion of the total current needs to be transferred to the mating contact. This reduces the contact resistance.

[0034] In Fig. 4 In the case shown, a sleeve-shaped high-current contact strip 27 is arranged in the socket 13, which forms the corrugation 26. The high-current contact strip 27 comprises a resilient carrier strip 30 with two edge webs 28 and a plurality of contact webs 29 running perpendicular to the edge webs 28. A contact piece 31 is riveted onto each of the contact webs 29. The carrier strip 30 is preferably made of spring steel, in particular stainless spring steel, and the contact pieces 31 are made of copper. The copper contact pieces 31 have a high heat absorption capacity, whereby a very high short-circuit current carrying capacity is achieved. The spring force required at the contact points is geometrically contained in the high-current contact strip, which is arranged in a ring shape, i.e., evenly distributed radially.

[0035] It is also possible to form the corrugation as contact lamellas. Furthermore, it would also be conceivable to form the corrugation on the movable contacts, i.e. on the movable pin. In this case, sleeves made of a high-current contact strip could be applied to the pin as described above, with the contact webs and thus also the contact pieces being formed on the outside of the sleeve. Furthermore, it is also conceivable to form two or more corrugations arranged parallel to one another in the direction of the longitudinal axis of the pin or sockets at each contact point. This can be achieved by arranging two or more of the sleeve-shaped high-current contact strips parallel to one another in the direction of the longitudinal axis L of the pin or sockets.

[0036] Fig. 5 shows an exploded view of a further detail of the switching device 1 from Fig. 1 , namely the movable pin 14 with the associated cylinders 19. The cylinders 19 are connected to the movable pin 14 via a holding plate 32. The connection between the cylinders 19, the holding plate 32 and the movable pin 14 is preferably also made via screw connections. The movable pin 14 has a central bore 33, which extends in the longitudinal direction L of the pin 14 and thus also in the longitudinal direction L of the bushings 13. The centering bolt 20 (see Fig. 3 ). The movable contacts 11 are formed on the pin 14.

[0037] Preferably, the switching device 1 is designed as a manual disconnector for the safe, galvanic separation of battery / voltage source and consumer in the case of maintenance in battery-operated trains, which in the operating state, when the disconnector is closed, can carry all currents that occur, ie operating currents up to 1000 A and short-time currents of 30 kA.

[0038] Depending on the design of the switching axis, the switching device can also be designed as a normally open contact or a changeover contact. It is therefore also possible for the switching device to comprise three or more contact points. In this case, a connection of several circuits is possible. In this case, several sockets are preferably arranged one behind the other in the housing of the switching device. The sockets are aligned coaxially to one another and form the fixed contacts. The movable contacts are all formed on a common movable pin. The movable pin is also aligned coaxially to the sockets and can interconnect several or all of the sockets.

[0039] Preferably, the switching device does not require any switching power and is used for load-free switching. List of reference symbols

[0040] 1Switching device 2Housing 3Side wall 4Side wall 5End wall 6End wall 7Base plate 8Cover 9Contact point 10Contact point 11Movable contact 12Fixed contact 13Socket 14Pin 15Solid block 16Connecting terminal 17Slot 18Slot 19Cylinder 20Centering bolt 21Switching mechanism 22Central bore 23Retaining plate 24Screw 25Inside of socket 26Ribbing 27High-current contact strip 28Edge webs 29Contact webs 30Carrier strip 31Contact pieces 32Retaining plate 33Bore Longitudinal direction

Claims

1. Switching device (1) for conducting high continuous currents and very high short-circuit currents having at least two contact locations (9, 10), wherein each contact location comprises a movable contact (11) and a fixed contact (12), one of the contacts (12) of each contact location (9, 10) being formed in a socket (13) and the other contact (11) of each contact location (9, 10) being formed on a pin (14) which can be received in the socket (13), and the movable contacts (11) of both contact locations (9, 10) being in the form of a common component; wherein one of the contacts (12) at at least one of the contact locations (9, 10) has ribs (26), so that at the contact location (9, 10) a plurality of contact points is defined, the ribs being a separate component in the form of contact lamellae, said component being arranged on the corresponding contact of each contact location, and the contact lamellae being in the form of a high-current contact strip (27), characterized in that the high-current contact strip (27) comprises a resilient carrier strip (30) having two boundary flanges (28) and comprises a plurality of contact webs (29), which run transversely to the boundary flanges (28) and are connected to the boundary flanges (28), wherein contact pieces (31) are riveted onto the contact webs (29).

2. Switching device (1) according to claim 1, characterized in that the fixed contact (12) of each of the at least two contact locations (9, 10) is formed in a respective socket (13) and the movable contacts (11) of the at least two contact locations (9, 10) are formed on a common pin (14).

3. Switching device according to claim 2, characterized in that at least one third contact location is provided, which comprises a fixed contact configured as a socket and a movable contact, wherein the movable contact of the third contact location is also formed on the common pin.

4. Switching device (1) according to at least one of the preceding claims, characterized in that the pin (14) is received in at least one of the sockets (13) in each switching position.

5. Switching device (1) according to claim 1, characterized in that the carrier strip (30) is made of spring steel and the contact pieces (31) are made of copper.

6. Switching device according to at least one of claims 1 to 5, characterized in that one of the two contacts has two ribs arranged next to each other at at least one of the contact locations in the longitudinal direction of the sockets and the pin.

7. Switching device (1) according to at least one of the preceding claims, characterized in that the pin (14) has a central bore (33) which runs in the longitudinal direction of the pin (14) and is in engagement with a centering bolt (20).

8. Switching device (1) according to at least one of claims 2 to 7, characterized in that each of the sockets (13) is received in a solid block (15).

9. Switching device (1) according to claim 8, characterized in that each of the solid blocks (15) is electrically conductively connected to a connecting terminal (16).

10. Switching device (1) according to at least one of claims 2 to 9, characterized in that the pin (14) is movable by means of at least one, preferably two cylinders (19).

11. Switching device (1) according to at least one of the preceding claims, wherein the switching device is configured as a normally open contact or as a normally closed contact or as a changeover contact.

12. Switching device (1) according to at least one of the preceding claims, wherein the switching device is configured as a manual disconnector.