Contact arrangement for electrical switching device and electrical switching device

Abstract

To provide an electrical switching device capable of withstanding short-circuit currents.SOLUTION: A contact arrangement (100) comprises two fixed contacts (102) and an electrically conductive contact bridge (104) which can be moved along a switching direction (118). The two fixed contacts (102) each have at least one first leg (122) and one second leg (124), wherein the two fixed contacts (102) are each connected to an outer surface of the second leg (124), which is located on an outer side of a projection volume spanned by the first leg (122) and by the second leg (124) and can be electrically contacted by at least one switching contact element (112) of the contact bridge (104). Furthermore, the present disclosure relates to an electrical switching device with such a contact arrangement (100).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a contact arrangement for an electrical switching device, such as a high voltage contactor or relay, for example an electrical DC switching device, and further to an electrical switching device having such a contact arrangement. [Background technology]

[0002] In many technical fields, electrical circuits are opened and closed for control purposes by switching devices (hereinafter also referred to as "switching elements"). In most cases, mutually compatible contact elements are separated from each other or brought into contact with each other by an actuation device. When closed, current flows through the circuit, allowing the operation of electrical devices and modules placed in the circuit. When opened, the flow of current is interrupted, thereby making it possible to stop the operation of the circuit if necessary.

[0003] In many applications, for example in the field of electric mobility, a short circuit in a circuit can cause an excessive current to flow, which is also forced through the contact elements of the switching element. This so-called short-circuit current usually continues to flow until the circuit's electrical fuse (e.g., a safety fuse) responds. For at least the fuse's reaction time, the short-circuit current endangers not only the switching element and all other components in the circuit, but also the surrounding area of ​​the circuit. In particular, to achieve shorter charging times for traction batteries, the internal resistance of traction batteries is continuously reduced in modern applications in the field of electric mobility. However, this has the disadvantage that the current peaks of short-circuit currents in circuits with such traction batteries are reaching increasingly high values ​​and can currently reach values ​​of 20 kA or even higher.

[0004] Due to the strong repulsive force (hereinafter also referred to as "repulsive force") that occurs in the event of a short circuit with such current, conventional switching devices are subject to uncontrollable opening of the contact elements, which may result in the contact elements being damaged by a strong arc, or the electrical switching element exploding, or plasma leaking from the electrical switching device. To prevent this uncontrollable opening in the event of a short circuit, a high contact force is required to counteract the repulsive force. To generate a high contact force, a correspondingly large drive element is required. Because the repulsive force increases quadratically with the short-circuit current, simply increasing the size of the drive element results in a drastic increase in the space required for the electrical switching element, which is particularly inconvenient in vehicles due to the inevitable limitations of available space. Summary of the Invention [Problem to be solved by the invention]

[0005] Thus, there is a need for an electrical switching device that can withstand short circuit currents for as long as possible without endangering people or the environment, and that can be manufactured safely and reliably, yet still cost-effectively. [Means for solving the problem]

[0006] This problem is solved by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.

[0007] According to a first aspect, there is provided a contact arrangement for an electrical switching device, the contact arrangement comprising two fixed contacts spaced apart from one another along an arrangement direction and a conductive contact bridge movable along a switching direction, the conductive contact bridge having a conductive switching contact element for making contact with each of the two fixed contacts, the contact arrangement having at least a closed position and an open position, wherein in the closed position, the switching contact elements of the contact bridge establish electrical contact with the respective corresponding fixed contacts, and in the open position, the switching contact elements of the contact bridge have a predetermined contact distance measured in the switching direction relative to the respective corresponding fixed contact. Each of the two fixed contacts has at least a first leg and a second leg, and each of the two fixed contacts is contactable by at least one of the switching contact elements of the contact bridge on the outer surface of the second leg located outside the projected volume spanned by the first leg and the second leg.

[0008] In particular, the present disclosure is based on the inventive concept of designing the fixed contacts such that, in the closed state of the contact device, they form, together with the contact bridges, a loop that shields the contact bridges as much as possible from magnetic fields that arise due to the current flow in the fixed contacts and that induce repulsive forces on the contact bridges. In particular, each second leg of the fixed contacts functions as a spacer between the respective first leg and the contact bridge, so that the repulsive (or repulsive) forces induced on the contact bridges by the current flow in the first legs are attenuated by this distance. Furthermore, the fixed contacts are designed such that the contact bridges are located outside the projected volume spanned by the fixed contacts in the closed and open positions, thus ensuring easy assembly of the contact device and, in particular, allowing the use of conventional actuation devices for switching the contact device. Likewise, this design makes it easy to influence the arc that occurs between the contact elements of the individual contacts when the contact arrangement is opened, for example by means of a blow-off magnet mounted on the switching device, and it is possible to adjust the overstroke of the contact bridge on the armature.

[0009] Thus, due to the specific design of the fixed contact, the contact device is particularly able to attenuate the repulsive force between the fixed contact and the contact bridge in the event of a short circuit, and therefore is able to at least delay or even completely prevent the opening of the contact bridge even at high short circuit currents of up to 20 kA, while at the same time assembling and operating the contact device is less complicated than conventional contact devices.

[0010] According to a second aspect, in the open position, the contact bridge is located outside the projected volume spanned by the first leg and the second leg, which allows the spring element to prestress the contact bridge in the open position in the direction opposite to the closing direction, potentially simplifying the design of the contact device and the corresponding drive element, thereby facilitating assembly of the contact device and the corresponding drive element.

[0011] According to a third aspect, each of the two fixed contacts has at least one fixed contact element that forms a contact pair with a corresponding switching contact element of the contact bridge. Here, the at least one fixed contact element is located at an end of the second leg opposite to the first leg. This may reduce the contact resistance between the fixed contact and the contact bridge while maximizing the distance between the contact bridge and the first leg of the fixed contact. Therefore, the repulsive force induced in the contact bridge by the current flowing through the first leg can be attenuated to the maximum extent.

[0012] In an optional implementation of the third aspect, in each contact pair, the fixed contact element and the corresponding switching contact element are arranged offset relative to each other at least along the arrangement direction, so that the current distribution at the contacts occurring between the fixed contact element and the switching contact element in the closed position can be controlled so that at least a part of the current flow through the contacts occurring in a direction parallel to the switching direction of the contact bridge occurs at a greater distance from the contact bridge, and thus the field strength of the magnetic field generated by the current flow through the contacts of the contact device (parallel to the switching direction) is reduced by the newly created distance in the region of the contact bridge. Such a magnetic field also generates a repulsive force on the contact bridge due to the Lorentz force (as does the current in the first leg of the fixed contact), so that the offset of the corresponding fixed and switching contact elements relative to each other can also attenuate the repulsive force acting on the contact bridge in the closed position.

[0013] According to a fourth aspect, the second legs are aligned parallel to the longitudinal direction of the contact bridge, which extends parallel to the arrangement direction. This allows the first legs to be positioned at a maximum distance from the contact bridge, preventing the current flow in the second legs from generating a magnetic field that induces a repulsive force in the contact bridge. This further attenuates the repulsive force induced in the contact bridge by the current flow in the fixed contact, further delaying or even completely preventing the opening of the contact bridge even at high short-circuit currents of up to 20 kA.

[0014] According to a fifth aspect, the first legs are each aligned parallel to the switching direction of the contact bridge, so that the current flow in the fixed contact, which flows perpendicular to the longitudinal direction of the contact bridge and thereby induces a repulsive force on the contact bridge, can be guided as far away from the contact bridge as possible, so that the repulsive force induced on the contact bridge is attenuated by this distance.

[0015] According to a sixth aspect, the first and second legs are each plate-shaped, and the second leg is arranged at an angle to the first leg. In particular, the second leg is preferably arranged perpendicular to the first leg, so that the first and second legs form an "L" shape. This allows for a particularly simple design of the fixed contact, which in turn allows for easy assembly of the contact device.

[0016] According to a seventh aspect, the second legs have at least one leg in which a current flowing through the second leg generates an attractive force on the contact bridge that pushes the contact bridge towards the two fixed contacts. In other words, the second leg of each of the fixed contacts is specifically designed so that a current flowing through the second leg generates a magnetic field that induces an attractive force on the contact bridge that counteracts the repulsive force generated by the current flowing through the first leg. Thus, even at high short-circuit currents of up to 20 kA, opening of the contact bridge can be further delayed or even completely prevented.

[0017] According to an eighth aspect, the second leg is designed in a stepped manner. In particular, the second leg is preferably arranged perpendicular to the first leg, so that the first and second legs together form part of a "G" shape. This allows for a particularly simple construction of the fixed contact, which in turn allows for easy assembly of the contact device.

[0018] According to a ninth aspect, in each of the two fixed contacts, at least one second leg is arranged parallel to the first leg, and the current flowing through the at least one leg parallel to the switching direction in the closed position flows in the opposite direction to the current flowing through the first leg parallel to the switching direction in the closed position. In other words, the current flowing through the at least one leg parallel to the switching direction in the closed position is opposite to the current flowing through the first leg parallel to the switching direction in the closed position. Thus, in the closed position of the contact bridge, antiparallel current flows exist in the two legs. As a result, the current flow in the second leg generates an attractive magnetic field that cancels the magnetic field generated in the first leg. This attenuates the repulsive force acting on the contact bridge, further delaying or even completely preventing the opening of the contact bridge even at high short-circuit currents of up to 20 kA.

[0019] According to a tenth aspect, in each of the two fixed contacts, the distance between the first leg and the contact bridge is greater than the distance between at least one of the second legs and the contact bridge. This allows the magnetic field generated by the current flow in the first leg, which exerts a repulsive force on the contact bridge, to be shielded more effectively than the magnetic field generated by the current flow in the second leg, which exerts an attractive force on the contact bridge. Therefore, due to the second leg being spatially closer to the contact bridge than the first leg, the overall force acting on the contact bridge is an attractive force in the closing direction, i.e., the contact bridge is pushed toward the closed position by the current flow in the fixed contact. This means that opening of the contact bridge can be further delayed or even completely prevented, even at high short-circuit currents of up to 20 kA.

[0020] According to an eleventh aspect, in each of the two fixed contacts, the length of at least one of the second legs along the switching direction is at least half the length of the first leg along the switching direction. Since the magnetic field generated in the at least one of the second legs varies depending on the length of the at least one leg, the length of the at least one leg may advantageously be between 70% and 90% of the length of the first leg along the switching direction.

[0021] According to a twelfth aspect, in each of the two fixed contacts, the first leg has at least two current conducting elements separated from each other by an air gap and electrically connected to the second leg separately. This allows the distance between the current conducting elements of the first leg and the contact bridge to be further increased, thereby reducing the repulsive force induced in the contact bridge by the current flow in the first leg. This makes it possible to at least delay or even completely prevent the opening of the contact bridge even in the case of high short-circuit currents of up to 20 kA.

[0022] According to a thirteenth aspect, the first leg of each of the two fixed contacts is at least partially surrounded by a first flow-guiding element that at least partially shields the magnetic field generated in the first leg by the current flow in the direction of the contact bridge, thereby attenuating the repulsive force induced in the contact bridge by the current flow in the first leg, which means that opening of the contact bridge can be further delayed or even completely prevented even at high short-circuit currents of up to 20 kA.

[0023] In a further or alternative implementation of the thirteenth aspect, the contact device further comprises at least one ferromagnetic flow-guiding element that exerts an attractive force on the contact bridge at least in the closed position, thereby at least attenuating the repulsive force induced on the contact bridge by the current flow in the stationary contact, thereby further delaying or even completely preventing the opening of the contact bridge even at high short-circuit currents of up to 20 kA.

[0024] According to a fourteenth aspect, in each of the second legs, the contact section, where the corresponding switching contact element of the contact bridge establishes electrical contact with the second leg, is thinner than the connection section connecting the contact section to the corresponding first leg, the thicknesses of the contact section and the connection section being measured parallel to the switching direction. This allows for spatial restriction of current flow occurring parallel to the switching direction of the contact bridge in the contact section of the fixed contact, i.e., in the region of the fixed contact where the fixed contact element is located, so that such current flow occurs partially further away from the contact bridge. This reduces the field strength of the magnetic field generated by such current flow through the contacts of the contact device (parallel to the switching direction) in the region of the contact bridge. Such a magnetic field also generates a repulsive force on the contact bridge due to the Lorentz force (as well as the current in the first leg of the fixed contact), thereby also attenuating the repulsive force generated at the contact bridge by the current flow through the contacts, so that the opening of the contact bridge can be further delayed or even completely prevented, even at high short-circuit currents of up to 20 kA.

[0025] According to a fifteenth aspect, there is provided an electrical switching device comprising a contact device according to one of the above-mentioned aspects and an actuation device designed to move a contact bridge of the contact device between a closed position and an open position. In particular, the actuation device moves the contact bridge between a closed position and an open position outside the projected volume spanned by the first and second legs, respectively. This allows the repulsive force between the fixed contact and the contact bridge to be attenuated in the event of a short circuit, and therefore allows the opening of the contact bridge to be at least delayed or even completely prevented, even at high short-circuit currents of up to 20 kA, while at the same time the assembly and operation of the contact device are less complicated than conventional contact devices. Likewise, this design improves the ability of, for example, a blow-off magnet mounted on the switching device to influence arcs that occur between the contact elements of the individual contacts when the contact arrangement is opened.

[0026] According to a sixteenth aspect which may be realized alone or in combination with one or more of the preceding aspects, there is provided a contact arrangement for an electrical switching device, the contact arrangement comprising: two fixed contacts spaced apart from each other along an arrangement direction; and a conductive contact bridge movable along a switching direction, the conductive contact bridge having a conductive switching contact element for establishing contact with each of the two fixed contacts, the contact arrangement having at least a closed position and an open position, wherein in the closed position, the switching contact elements of the contact bridge establish electrical contact with the respective corresponding fixed contacts, and in the open position, the switching contact elements of the contact bridge have a predetermined contact distance measured in the switching direction relative to the respective corresponding fixed contact. In each of the fixed contacts, the contact portion at which the switching contact element of the contact bridge establishes electrical contact with the corresponding fixed contact is thinner than the portion of the fixed contact adjacent to the contact portion, the thicknesses of the contact portion and the adjacent portion being measured parallel to the switching direction.

[0027] A sixteenth aspect is also based on the inventive concept explained above and is intended to help design the fixed contact so that, when the contact device is in the closed state, it forms, together with the contact bridge, a loop that is shielded as much as possible from the magnetic field that arises due to the current flow in the fixed contact and that induces a repulsive force on the contact bridge. In particular, the specific design of the contact part of the fixed contact, i.e., the area of ​​the fixed contact where the fixed contact element is located, makes it possible to spatially limit to a maximum length the current flow that occurs parallel to the switching direction of the contact bridge. This reduces the field strength of the magnetic field that is formed by such a current flow through the contacts of the contact device (parallel to the switching direction) in the area of ​​the contact bridge. Such a magnetic field also generates a repulsive force on the contact bridge due to the Lorentz force (as well as the current in the first leg of the fixed contact), thereby also attenuating the repulsive force generated at the contact bridge by the current flow through the contacts, so that the opening of the contact bridge can be further delayed or even completely prevented, even at high short-circuit currents of up to 20 kA.

[0028] According to a seventeenth aspect, which may be provided particularly in combination with the sixteenth aspect, each of the two fixed contacts has at least one fixed contact element which forms a contact pair with a corresponding switching contact element of the contact bridge, and in each contact pair the fixed contact element and the corresponding switching contact element are arranged offset relative to each other at least along the arrangement direction, which also contributes to controlling the current distribution in the contacts occurring between the fixed contact element and the switching contact element in the closed position such that at least part of the current flow through the contacts occurring in a direction parallel to the switching direction of the contact bridge occurs at a greater distance from the contact bridge. Thus, the field strength of the magnetic field created by the current flow through the contacts of the contact device (parallel to the switching direction) is reduced by the newly created distance in the region of the contact bridge, which also attenuates the repulsive force acting on the contact bridge in the closed position.

[0029] For a better understanding, the present invention will be explained in more detail by the examples shown in the following drawings. The same parts are given the same reference numerals and the same component names. Furthermore, some features or combinations of features from the various embodiments shown and described may correspond to independent inventions or inventive solutions, as shown below. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a schematic perspective view of a first exemplary contact device. [Figure 2] 1 is a schematic perspective view of a stationary contact of a first exemplary contact device. FIG. [Figure 3] 1 is a schematic side view of a first exemplary contact device. [Figure 4] 4 is a schematic diagram of the magnetic field strength generated at the stationary contact of the first exemplary contact device. FIG. [Figure 5] 1 is a schematic side view of an alternative design of the first exemplary contact device. [Figure 6] 10 is a schematic side view of a further alternative design of the first exemplary contact device. [Figure 7] 10 is a schematic side view of a further alternative design of the first exemplary contact device. [Figure 8] FIG. 10 is a schematic perspective view of a second exemplary contact device. [Figure 9] FIG. 10 is a schematic top view of a second exemplary contact device. [Figure 10] FIG. 10 is a schematic perspective view of a third exemplary contact device. [Figure 11] FIG. 10 is a further schematic perspective view of a third exemplary contact device. [Figure 12] FIG. 10 is a schematic perspective view of a stationary contact of a third exemplary contact device. [Figure 13] FIG. 10 is a schematic side view of a third exemplary contact device. [Figure 14] 14 is a schematic cross-sectional view of the third exemplary contact device taken along the section line XIV-XIV shown in FIG. 13. [Figure 15] 15 is a schematic cross-sectional view of the third exemplary contact device taken along the section line XV-XV shown in FIG. 11. [Figure 16] 15 is a further schematic cross-sectional view of the third exemplary contact device taken along section line XV-XV shown in FIG. 11. [Figure 17] FIG. 10 is a schematic side view of a portion of a fourth exemplary contact device. [Figure 18] 18 is an enlarged view of the contact area between the fixed contact and the contact bridge shown in FIG. 17. DETAILED DESCRIPTION OF THE INVENTION

[0031] The present disclosure will now be explained in more detail with reference to the drawings, and first to the schematic perspective views of Figures 1 and 2. In all figures, proportions and in particular layer thicknesses are not necessarily shown to scale. Furthermore, parts that are not necessary for or that would interfere with understanding, in particular electrically insulating housing elements and protective covers, are not shown.

[0032] 1 illustrates a first exemplary contact arrangement 100 that may be part of a switching element. In particular, contact arrangement 100 may be mounted in a housing of the switching element and / or may have its own housing, preferably made of a non-conductive material. Additionally, an actuation device may be mounted in the housing and at least partially force-transmittingly connected to contact arrangement 100. The switching element may be, for example, an electrical DC switching element, such as a high-voltage contactor or relay. However, the present disclosure is not limited to DC and / or high-voltage applications and may be used in other electrical switching devices.

[0033] The contact device comprises two fixed contacts 102(1) and 102(2) and a contact bridge 104. The fixed contacts 102 each have the same shape as that shown in more detail in Figure 2. For installation of the switching element in an electric circuit (not shown) to be controlled, the fixed contacts 102 each have terminal portions 106(1), 106(2) that are spaced apart from each other and arranged so as to be accessible from the outside of the housing. The terminal portions 106(1), 106(2) are designed on their outer surfaces to receive an electrical conductor (not shown) or a fixing element for an electrical conductor (not shown).

[0034] Here, each of the two fixed contacts 102 is assigned a respective terminal portion 106(1), 106(2) disposed on the base portion 108 of the respective fixed contact 102. The conductive stationary contacts 102(1) and 102(2) of the contact device 100 are each held stationary relative to the housing and are spaced apart from each other, as are the corresponding terminal portions 106(1), 106(2). The fixed contacts 102(1) and 102(2) also each have at least one conductive fixed contact element 110 capable of establishing contact with a corresponding conductive switching contact element 112 of the contact bridge 104. The fixed contact element 110 and the switching contact element 112 may each be a plate-shaped contact element, although lens-shaped, dome-shaped or other shaped contact elements are also possible. The fixed contact elements 110 and corresponding switching contact elements 112 form contact pairs 114 that, when in contact, create contact points or contact sites (see FIG. 3 ). If desired, each of the fixed contacts 102 may have more than one fixed contact element 110 that can be brought into contact with a corresponding switching contact element 112 of the contact bridge 104, and thus multiple contact pairs 114 may be provided between each of the fixed contacts 102 and the contact bridge 104.

[0035] A movable conductive contact bridge 104 extends between the fixed contact elements 110. The contact bridge 104 is preferably a rod- or bar-shaped component extending along a contact bridge longitudinal direction 116. The two fixed contacts 102(1), 102(2) and the terminal portions 106(1), 106(2) are spaced apart from each other in the contact bridge longitudinal direction 116.

[0036] A switching contact element 112 capable of establishing contact with the fixed contact elements 110 of both fixed contacts 102(1), 102(2) is arranged on the contact bridge 104. In particular, the switching contact element 112 may be welded, soldered, pressed, riveted, or screwed to the contact bridge 104. Similarly, the fixed contact element 110 may be welded, soldered, pressed, or screwed to the fixed contacts 102(1), 102(2), respectively. Alternatively, the switching contact element 112 may be an integral component of the contact bridge 104 or may be applied to the contact bridge 104 as a coating. Similarly, the fixed contact elements 110 may be an integral component of the respective fixed contacts 102(1), 102(2) or may be applied as a coating to the respective fixed contacts 102(1), 102(2). To reduce the contact resistance between the fixed contacts 102(1), 102(2) and the contact bridge 104, the fixed contact elements 110 and the switching contact elements 112 may each be formed from silver or a silver alloy, among others.

[0037] The contact bridge 104 has at least an open position 103 (see FIG. 1 ) and a closed position 105 (see FIG. 3 ). Between the open position 103 and the closed position 105, the contact bridge 26 is preferably movable linearly along the switching direction 118. A drive device (not shown) may be used for this movement. In other words, the drive device may be configured to move the contact bridge 104 between the closed position 105 and the open position 103. In particular, the drive device may have an idle state in which the contact bridge 104 is in the open position 103 and an actuated state in which the contact bridge 104 may be in the closed position 105.

[0038] 1 , in the open position 103, the switching contact elements 112 of the contact bridge 104 are spaced apart from the corresponding fixed contact elements 110 of the fixed contacts 102(1) and 102(2). In particular, in the open position 103, the switching contact elements 112 have a predetermined contact distance D measured in the switching direction 118 from the corresponding fixed contact elements 110. Here, the switching contact elements 112 and the fixed contact elements 110 may be separated by an open gap 120 in the open position 103. This has the effect that current cannot flow between the terminal portions 106(1) and 106(2) through the contact bridge 104, or rather, any current flowing up to that point is interrupted. Thus, the circuit is opened.

[0039] 3 , in the closed position 105, the switching contact elements 112 of the contact bridge 104 establish electrical contact with the corresponding fixed contact elements 110 of the fixed contacts 102(1) and 102(2), respectively. This closes a circuit so that current can flow between the terminal portions 106(1) and 106(2) through the contact bridge 104. The closed position 105 represents normal operation of the contact device 100, with an operating current I (indicated by the current arrows) flowing through the terminal portions 106(1), 106(2), the fixed contacts 102(1), 102(2), and the contact bridge 104. Although the contact devices in the described example each have one contact bridge, alternatively, multiple (at least two) parallel contact bridges may be provided that are moved using a common drive device, with each of the multiple contact bridges in the closed position 105 electrically connecting the two fixed contacts 102(1) and 102(2). This may help to reduce the repulsive force between the fixed contact element 110 and the switching contact element 112.

[0040] In order to minimize the repulsive force on the contact bridge 104 in the closed position 105 when a short circuit occurs, each of the fixed contacts 102 in the first embodiment has a first leg 122 and a second leg 124, as shown in FIGS. 1 to 3. The first legs 122 extend downward from the base 108 of the fixed contact, respectively parallel to the switching direction 118 of the contact bridge 104. The second legs 124 are adjacent to the first legs 122 and extend parallel to the contact bridge longitudinal direction 116, respectively, and therefore function as spacers between the first legs 122 and the contact bridge 104. Here, the second legs 124 are arranged on the first legs 122 so that the first and second legs form an "L-shape." In particular, the first leg 122 and the second leg 124, together with the base 108 of the fixed contact 102, form a "C" shape in side view (see FIGS. 5-7). Thus, the longitudinal direction of the second leg 124 encloses an opening angle 126 with the longitudinal direction of the first leg 122, in particular of approximately 90°, although other opening angles may be selected instead depending on the application.

[0041] The fixed contact elements 110 are disposed on outer surfaces 128 of the fixed contacts 102(1) and 102(2), respectively, which are located outside a projected volume 125 formed by the outer surfaces of the second legs 124 and spanned by the first and second legs 122 and 124 (see FIG. 3 ). The projected volume 125 spanned by the first and second legs 122 and 124 should be understood as the volume that would be located within the fixed contacts 102(1) and 102(2) if the fixed contacts 102(1) and 102(2) were closed at their open sides by a (virtual) plate. In other words, the fixed contact elements 110 are disposed on the outer surfaces of the second legs 124 that face away from the base 108 and the corresponding terminal portions 106(1) and 106(2), respectively. Thus, the contact surface of the fixed contact element 110 faces the actuating device, and the actuating device can press the contact bridge 104 against the fixed contact element 110 from the outside, i.e., from outside the "C" shape spanned by the fixed contacts, in the switching direction 118, to electrically connect the two fixed contacts 102(1) and 102(2) to each other. Here, the actuating device of the switching element moves the contact bridge 104 between the closed position 105 and the open position 103 outside the projected volume 125 spanned by the first leg 122 and the second leg 124, respectively.

[0042] This has the advantage that the contact bridge 104 can be pressed against the fixed contact 102 from the outside by a drive device, thus avoiding the installation of a complex drive device. In particular, the contact bridge 104 can be biased in the open position 103 in the direction opposite to the closing direction by a spring element (not shown), which thus assists in the rapid opening of the contact bridge 104 when the bridge goes from the closed position 105 to the open position 103. Furthermore, it becomes easier to influence the arc by a blow-out magnet provided in the switching element.

[0043] The following discussion describes how the first exemplary contact device 100 operates when contact bridge 104 is in closed position 105. For example, when terminal 106(1) is connected to the high potential side of a circuit (e.g., the positive connection terminal of a drive battery), operating current I flows from terminal 106(1) through stationary contact 102(1) to contact bridge 104, as shown schematically in FIG. 3, and operating current I flows from there through stationary contact 102(2) to terminal 106(2), which may be connected, for example, to a load in the circuit. Contact device 100 may, of course, be connected in the opposite direction, such that current flows in the opposite direction. This does not affect the effects described below due to the symmetrical arrangement of stationary contacts 102(1) and 102(2) relative to one another.

[0044] As shown in Figure 3, due to the unique shape of the fixed contact 102(1), an operating current flows in the first leg 122 of the fixed contact 102(1) along (or parallel to) the switching direction 118 of the contact bridge and in a direction opposite to the closing direction, i.e., the direction opposite to the direction in which the actuation device exerts a force on the contact bridge 104 in the closed position 105. As shown schematically in Figure 4, the current flow in the first leg 122 of the fixed contact 102(1) generates a magnetic flux density B (also referred to below as "magnetic field B") that circularly surrounds the first leg 122 of the fixed contact 102(1). Similarly, the current flow in the first leg 122 of the fixed contact 102(2) generates a magnetic field B (not shown) that circularly surrounds the first leg 122 of the fixed contact 102(2) in the opposite direction. The magnetic field B generated in the first legs 122 of the fixed contacts 102(1) and 102(2) each exerts a Lorentz force on a current-carrying conductor extending horizontally relative to the first leg 122 of the fixed contact 102(1). Therefore, due to the alignment of the fixed contacts 102(1) and 102(2), the magnetic field B generated in the first legs 122 of the two fixed contacts 102(1) and 102(2) exerts a Lorentz force FL (see FIG. 3 ) on the operating current I flowing through the contact bridge 104, pushing the contact bridge 104 in a direction opposite to the closing direction of the contact bridge 104. Thus, current flow through the first legs 122 of the two fixed contacts 102(1) and 102(2) induces a repulsive force on the contact bridge 104, which acts in addition to the repulsive force that occurs between the fixed contact element 110 and the switching contact element 112 in each of the contact pairs 114 when current is applied, pushing the contact bridge toward the open position 103.

[0045] During normal operation of the switching element, i.e., at normal strengths of the operating current I in the range of less than 5 kA, the induced repulsive force can be counteracted by the driving force exerted by the driving device on the contact bridge 104, and the contact bridge 104 remains in the closed position 105. However, the magnetic field B generated in the first legs 122 of the two fixed contacts 102(1) and 102(2) depends linearly on the current strength of the operating current I, and therefore the Lorentz force FL acting on the contact bridge 104 in the direction of the open position 103 is I 2 Thus, in the event of a short circuit, particularly at currents above 5 kA, a repulsive force may act quickly on the contact bridge 104, which in known switching elements would force the contact bridge 104 to open. In this case, the contact bridge 104 may open before an overcurrent protection device, such as a fuse or pyrofuse, can safely disconnect the circuit, resulting in the release of energy present in the circuit in an arc between the open contacts of the known switching element, which can quickly cause unwanted and irreparable damage to the known switching element.

[0046] The forced opening due to the repulsive force translates into a higher current in the contact device 100 due to the unique geometry of the two fixed contacts 102(1) and 102(2). Because the internal inductance slows the current rise until the maximum short-circuit current is reached, the increased lift increases the time period before the overcurrent protection devices of the circuits connected to the contact device 100 can safely operate. As shown in Figure 4, the field strength of the magnetic field B generated by the current flow in the first legs 122 of the two fixed contacts 102(1) and 102(2) depends on the distance from the first legs 122. More precisely, the field strength of the magnetic field B is proportional to 1 / R, where R represents the distance between the measurement point and the first legs 122.

[0047] Thus, in the contact device 100, the effect of the magnetic field B generated in the first legs 122 of the two fixed contacts 102(1) and 102(2) due to the flow of current on the contact bridge 104 is attenuated by the distance r0 by which the first legs 122 are separated from the contact bridge 104 by the second legs 124 along the contact bridge longitudinal direction 116. The length r0 (see FIG. 3 ) of the second legs 124 along the contact bridge longitudinal direction 116 should be selected so as to reduce the repulsive force acting on the contact bridge 104 sufficiently to delay the opening of the contact device 100, but at the same time, should not exceed a certain length so as not to excessively increase the space requirements of the contact device 100. For example, depending on the application, the length r0 may be in the range of 10 mm to 25 mm to achieve attenuation of the repulsive force acting on the contact bridge 104 while avoiding an excessive increase in the size of a switching device including the contact device 100.

[0048] In particular, if the fixed contact elements 110 are each arranged at one end of the second leg 124 of the fixed contact 102 opposite the corresponding first leg 122 of the fixed contact, the distance between the first leg 122 of the fixed contact 102 and the contact bridge 104 can be increased. This allows the overall length r0 of the second leg 124 to be utilized to increase the distance between the first leg 122 and the contact bridge 104.

[0049] Furthermore, to reduce the penetration area through which the magnetic field B generated in the first leg 122 of the fixed contact 102 by the flow of current penetrates the contact bridge 104, the length L (see FIG. 3 ) of the contact bridge 104 along the contact bridge longitudinal direction 116 between the closing contact elements 112 may be selected to be as short as possible. However, the length L of the contact bridge must be at least long enough so that the fixed contact elements 110 of the two fixed contact elements 102(1) and 102(2) are sufficiently electrically isolated from each other in the open position 103 to prevent flashover. Therefore, the length L should not be less than a lower limit of, for example, 15 mm to 20 mm.

[0050] To further attenuate the magnetic field B generated by the current flow in the first legs 122 of the stationary contacts 102, the contact device 100 may include a first ferromagnetic flow-guiding element 130, as shown schematically in FIG. 5 . Here, the first flow-guiding element 130 may completely surround the first legs 122 of the two stationary contacts 102(1) and 102(2). To save material, the flow-guiding element may surround the first legs 122 of the two stationary contacts 102(1) and 102(2) only in the direction of the contact bridge 104 to attenuate the magnetic field B generated by the current flow in the first legs 122 in the direction of the contact bridge 104. The first flow-guiding element 130 should be made of a material with high magnetic permeability, such as iron or an iron alloy, to maximize shielding of the magnetic field B in the direction of the contact bridge 104.

[0051] To at least partially counteract the repulsive force acting on the contact bridge 104, the contact device 100 may optionally comprise at least a second ferromagnetic flow-guiding part 132, which is positioned to exert an attractive force on the contact bridge 104 (or more specifically on the operating current I flowing through the contact bridge 104) when the contact bridge 104 is in the closed position 105. As shown schematically in Figure 6, the second flow-guiding part 132 is arranged above the contact bridge along the switching direction 118, i.e. in the current loop formed by the fixed contact 102 and the contact bridge 104, so that the contact bridge 104 is pushed towards the fixed contact element 110 by the attractive force induced by the second flow-guiding part 132. Similar to the first flow guide element 130, the second flow guide element 132 should also be made of a material with high magnetic permeability, such as iron or an iron alloy, to maximize shielding of the magnetic field B in the direction of the contact bridge 104. The second flow guide element 132 may be provided together with or instead of the first flow guide element 130 (as in FIG. 6 ). As shown schematically in FIG. 7 , the first ferromagnetic flow guide element 130 and the second flow guide element 132 may be provided as a single-piece ferromagnetic insert 134 disposed between the fixed contacts 102, which attenuates the magnetic field B generated by the current flow in the first leg 122 in the direction of the contact bridge 104 and exerts an attractive force on the contact bridge 104 (or more specifically on the operating current I flowing through the contact bridge 104).

[0052] 8 and 9 show schematic diagrams of a second exemplary contact device 200. All components of the second exemplary contact device 200, particularly the fixed contacts 102 and the contact bridge 104, are designed as described for the first exemplary contact device 100, but the two fixed contacts 102(1) and 102(2) are each arranged asymmetrically. In particular, the fixed contacts 102(1) and 102(2) are arranged so that the longitudinal directions of the second legs 124 extend perpendicular to the contact bridge longitudinal direction 116 and the switching direction 118 of the contact bridge 104, respectively. This allows the arrangement of the second legs 124 to increase the distance between the first legs of the two fixed contacts 102(1) and 102(2) and the contact bridge 104, thereby reducing the repulsive force acting on the contact bridge 104. An example of the magnetic field B generated by the flow of operating current I in the first legs 122 of the two fixed contacts 102(1) and 102(2) is shown in Figure 9, where, for better illustration, the bases 108 of the fixed contacts 102 are not shown in any case.

[0053] 10-16, a third exemplary contact device 300, which differs from the first exemplary contact device 100 in the design of the fixed contacts 302(1) and 302(2), is described below. The fixed contacts 302(1) and 302(2) are also designed to have first and second legs 322 and 324, respectively, which function as spacers to ensure a constant distance between the first leg 322 of each of the fixed contacts 302 and the contact bridge 104.

[0054] As can be seen in the schematic perspective views of Figures 10 to 12, each of the second legs 324 of the two fixed contacts 302(1) and 302(2) has an additional leg 332 extending parallel to the first leg 322 of the two fixed contacts 302(1) and 302(2), respectively. In the leg 332, when the contact bridge 104 is in the closed position 105, an electrical operating current I flowing through the fixed contact 302 generates an attractive force on the contact bridge 104 that pushes the contact bridge 104 toward the two fixed contacts 302(1) and 302(2). Thus, the attractive force generated by the current flow in the leg 332 counteracts the repulsive force generated by the current flow in the first leg 322, and at least partially cancels out the repulsive force if it does not exceed the repulsive force.

[0055] As described for the first exemplary contact device, the first legs 322 of the fixed contacts 302 also extend downward from the base 308, each having a connecting element 306 parallel to the switching direction 118 of the contact bridge 104. The second legs 324 are adjacent to the first legs 322. To ensure a compact design of the fixed contacts 302, the second legs 324 are advantageously formed in a stepped shape. In particular, the second legs 324 have a connecting portion 334 connecting the first legs 322 to a leg 332 of the second legs 324. Here, the connecting portion 322 is advantageously aligned parallel to the contact bridge longitudinal direction 116 in order to maximize the distance between the first legs 322 and the leg 332 of the second legs 324. Furthermore, the second leg comprises a contact protrusion 336 which projects from the leg 332 along the contact bridge longitudinal direction 116 and on which the fixed contact element 310 is arranged.

[0056] The aforementioned portions of the second leg 324 may each be designed in the shape of a plate, for example formed as a rectangular bus bar. The fixed contact element 310 may be welded, soldered, pressed or screwed to the contact protrusion 336, for example.

[0057] In order to cancel out as much as possible the repulsive force acting on the contact bridge 104 due to the current flow in the first leg 322, the leg 332 of the second leg 324 is arranged parallel to the first leg, in particular such that the longitudinal direction of the second leg extends perpendicular to the contact bridge longitudinal direction 116. Here, the leg 332 of the second leg 324 is aligned such that the current component of the operating current I along the switching direction 118 in the leg 332 is opposite to the current component of the operating current I in the first leg. In particular, the current direction of the operating current I in the leg 332 of the second leg 324 should extend parallel to the closing direction of the contact bridge 104 from the open position 103 to the closed position 105.

[0058] To ensure a compact design of the fixed contact 302, the connecting portion 334 and the contact protrusion 336 are preferably arranged perpendicular to the leg 332, so that the connecting portion 334 in particular surrounds an opening angle 326 of approximately 90° with the longitudinal direction of the first leg 322. However, other opening angles may be selected depending on the requirements of the application. Thus, the second leg 324 is arranged on the first leg 322 such that the first leg 322 and the second leg 324 form a "G" shape in side view together with the base 308 of the fixed contact 302 (see FIG. 13).

[0059] The fixed contact elements 310 are each disposed on an outer surface 328 of the fixed contacts 302(1) and 302(2), which is formed by the outer surface of the contact protrusion 336 of the second leg 324 and located outside the projected volume 325 spanned by the first leg 322 and the second leg 324 (see FIG. 13 ). The projected volume 325 spanned by the first leg 322 and the second leg 324 should be understood as the volume that would be located within the fixed contacts 302(1) and 302(2) if the fixed contacts were closed by a (virtual) plate on the opening side. In other words, the fixed contact elements 310 are disposed on the outer surface of the contact protrusion 336 of the second leg 324 facing away from the base 308 and the corresponding terminal portion 306, respectively. Thus, the two fixed contacts 302(1) and 302(2) can be electrically connected to each other by pressing the contact bridge 104 against the fixed contact element 310 from the outside in the switching direction 118, i.e., from outside the "G" shape spanned by the fixed contacts, with the contact surface of the fixed contact element 310 facing the actuating device. Here, the actuating device of the switching element moves the contact bridge 104 between the closed position 105 and the open position 103 outside the projected volume 325 spanned by the first leg 322 and the second leg 324, respectively.

[0060] This has the advantage that the contact bridge 104 can be pressed from the outside against the fixed contact 302 by an actuation device, thereby avoiding the need to install a complex actuation device. In particular, the contact bridge 104 can be biased in the open position 103 against the closing direction by a spring element (not shown), which thus assists in the rapid opening of the contact bridge 104 when the bridge goes from the closed position 105 to the open position 103. Furthermore, it simplifies the influence of the electric arc by a blow-out magnet provided in the switching element.

[0061] The following is a description of the operation of the third exemplary contact device 300 when the contact bridge 104 is in the closed position 105. Again, it is assumed that the fixed contact 302(1) is connected to the high potential side of the circuit (e.g., the positive terminal of the drive battery) via the connecting element 306, and therefore the operating current I flows from the fixed contact 302(1) through the contact bridge 104 to the fixed contact 302(2), as shown schematically in FIG. 13. Due to the particular shape of the fixed contact 302(1), the operating current I flows in the first leg 322 of the fixed contact 302(1) along (or parallel to) the switching direction 118 of the contact bridge 104 in a direction opposite to the closing direction of the contact bridge 104. In contrast, in the leg 332 of the second leg 324 of the fixed contact 302(1), the operating current I flows in the direction of the closing direction of the contact bridge 104 along (or parallel to) the switching direction 118 of the contact bridge 104. In the fixed contact 302(2), the operating current flows in the opposite direction along the switching direction 118 in each individual element compared to the fixed contact 302(1).

[0062] 14, a magnetic field B0 that circularly surrounds the first legs 322 of the two fixed contacts 302(1) and 302(2) is generated by the flow of current in the first legs 322 of the two fixed contacts 302(1) and 302(2). Similarly, a magnetic field B1 that circularly surrounds the legs 332 of the second legs 324 of the two fixed contacts 302(1) and 302(2) is generated by the flow of current in the first legs 322 of the two fixed contacts 302(1) and 302(2). Due to their alignment, the magnetic field B0 generated in the first legs 322 of the two fixed contacts 302(1) and 302(2) acts in the direction opposite to the closing direction of the contact bridge 104, and exerts a Lorentz repulsive force I on the operating current I flowing through the contact bridge 104, pushing the contact bridge 104 toward the open position 103. In contrast, the magnetic field B1 generated in the leg 332 of the second leg 324 of the two fixed contacts 302(1) and 302(2) is oriented in such a way that it exerts a Lorentz attractive force FA (FIGS. 13 and 14) on the operating current I flowing through the contact bridge 104. The Lorentz attractive force FA acts in the closing direction of the contact bridge, pushing the contact bridge 104 towards the closed position 105.

[0063] Thus, the flow of current in the leg 332 of the second leg 324 of the two fixed contacts 302(1) and 302(2) induces an attractive force FA (see FIGS. 13 and 14 ) on the contact bridge 104, which, when energized, counteracts the repulsive force between the fixed contact element 110 and the switching contact element 112 in each of the contact pairs 114 and pushes the contact bridge toward the closed position 105. In particular, the attractive force FA also counteracts the repulsive force resulting from the flow of current in the first legs 322 of the two fixed contacts 302(1) and 302(2). This additional attractive force FA ensures that, in the event of a short circuit at currents up to 20 kA, an undesired opening of the contact bridge 104 in the contact device 300 is prevented, or at least delayed until an overcurrent protection device in the circuit connected to the contact device 300 is activated.

[0064] Since the magnetic field generated in the fixed contact 302 is distance dependent, the distance r0 between the first leg and the contact bridge 104 along the contact bridge longitudinal direction 116 should advantageously be greater than the distance r1 between the leg 332 of the second leg 324 and the contact bridge 104 along the contact bridge longitudinal direction 116, respectively. Thus, the attractive force FA induced at the contact bridge 104 by the current flow in the fixed contact 302 can be maximized relative to the repulsive force induced at the contact bridge 104 by the current flow in the fixed contact 302. The ratio of the distance r0 to the distance r1 can be defined by the length of the connecting element 334. Here, the distances r0 and r1 (see FIG. 13) may be selected so that the repulsive force acting on the contact bridge 104 is offset by the attractive force FA sufficiently strong to delay the opening of the contact device 300, but at the same time should not exceed a certain distance to prevent the space requirement of the contact device 300 from becoming too large. To achieve a typical installation space size, for example, r1 may be selected within a range of approximately 4 mm to 8 mm, while r0 is selected within a range of approximately 15 mm to 20 mm.

[0065] In order to further maximize the attractive force FA, the length L of the contact bridge 104 along the contact bridge longitudinal direction 116 (see FIG. 13) between the closing contact elements 112 may be selected to be as long as possible in order to increase the penetration area through which the magnetic field B1 generated in the leg 332 of the second leg 324 of the fixed contact 302 by the flow of current penetrates the contact bridge 104.

[0066] A fixed contact having at least a first current conducting element 338 and a second current conducting element 340 separated from one another by an air gap 342 can further increase the distance between the first leg 322 of the fixed contact 302 and the contact bridge 104, such that the first current conducting element 338 and the second current conducting element 340 are offset relative to one another and relative to the contact bridge 104 in the contact bridge transverse direction 136 (see FIGS. 15 and 16 ). By way of illustration, FIG. 16 shows a schematic diagram of the resulting magnetic field B0 generated when current flows through the first current conducting element 338 of the first leg 322 of the fixed contact 302(2), and the magnetic field B1 generated when current flows through the leg 332 of the second leg 324 of the fixed contact 302(2).

[0067] The magnetic field generated in at least one leg 332 of second leg 324 varies depending on the length h1 (see FIG. 12 ) of at least one leg 332 between connecting portion 334 and contact protrusion 336, so that length h1 of at least one leg 332 may be at least half the length h0 of first leg 322 between connecting portion 334 of second leg 324 and base 308. Depending on the magnitudes of distances r0 and r1, length h1 of at least one leg 332 of second leg 324 may be selected to be longer than length h0 of first leg 322, and h1 may be, for example, between 70% and 90% of h0.

[0068] To further attenuate the magnetic field B generated in the first legs 322 of the stationary contacts 302 due to the flow of current, the contact device 300 may include a first flow guide element 130, as shown schematically in FIGS. 13 and 14 . In this case, the first flow guide element 130 may completely surround the first legs 322 of the two stationary contacts 302(1) and 302(2). To save material, the first flow guide element 130 may surround the first legs 322 of the two stationary contacts 302(1) and 302(2) only in the direction of the contact bridge 104 to attenuate the magnetic field B generated in the first legs 322 due to the flow of current in the contact bridge 104. The first flow guide element 130 should be made of a material with high magnetic permeability, such as iron or an iron alloy, to maximize shielding of the magnetic field B in the direction of the contact bridge 104. To at least partially counteract the repulsive force acting on the contact bridge 104, the contact device 300 may optionally include at least a second ferromagnetic flow-guiding component 132, which is aligned to exert an attractive force on the contact bridge 104 (or more specifically on the operating current I flowing through the contact bridge 104) when the contact bridge 104 is in the closed position 105. Alternatively, a single-component ferromagnetic insert 134 may be disposed in the contact device 300 between the two fixed contacts 302(1) and 302(2), which ferromagnetic insert 134 is aligned to attenuate the magnetic field B generated by the current flow in the first leg 322 in the direction of the contact bridge 104 and to exert an attractive force on the contact bridge 104.

[0069] In each of the examples shown above, the movement of the contact bridge 104 may be stabilized by a support structure 150 of the contact device, which movably holds the contact bridge 104. In particular, the contact bridge 104 may be attached via the support structure 150 to a shaft 152 that transmits the force generated by the actuation device to the contact bridge 104. The support structure 150 in each of the examples shown above may optionally include an overstroke spring 154 that prestresses the contact bridge 104 in the direction of the closed position 105. Compression of the overstroke spring 154 generates a contact force, which in turn makes it possible to compensate for position differences, manufacturing tolerances, and operating wear between the contact pairs 114 at different ends of the contact bridge 104.

[0070] 17 and 18 show a portion of a schematic side view of a fourth exemplary contact device 400, where only one of the two stationary contacts 402, in this case stationary contact 402(1), is shown. FIG. 18 shows an enlarged view of the contact area between the stationary contact 402 and the contact bridge 104 of FIG. 17. The fourth exemplary contact device 400 differs from the exemplary contact devices 100, 200, and 300 shown above by the unique shape of the stationary contact, as well as by the resulting reduced thickness of the stationary contact at the contact region 456 (along the switching direction 118) when compared to the connection region 458 adjacent to the contact region 456. As will be explained below, this reduced thickness at the contact region 456 also contributes to a reduced repulsive force acting on the contact bridge 104. Thus, the configurations of contact region 456 (and connection region 458) described below may be provided in each of second legs 124 and 324 of example contact devices 100, 200 and 300. However, the configurations described below may also be used with stationary contacts having shapes other than those described thus far.

[0071] 17 and 18, the fixed contact 402 of the fourth exemplary contact device 400 has the same basic structure as the fixed contact 102 of the first exemplary contact device 100. The base 408, first leg 422, and second leg 424 of the fixed contact 402 are arranged so that the fixed contact 402 has a "C" shape when viewed in side view. In addition, the second leg 424 has a contact portion 456 to which the fixed contact element 410 is attached and a connecting portion 458 adjacent to the contact portion 456 and connecting the contact portion 456 to the first leg 422. As shown in FIGS. 17 and 18, the contact portion 456 is designed to be thinner than the connecting portion 458 in the switching direction 118. Thus, the contact portion 456 protrudes as a protrusion from the thicker portion of the second leg 424 formed by the connecting portion 458. In this case, the upper surface 460 of the contact portion 456 is offset downwardly relative to the upper surface 462 of the connection portion 458 in the switching direction 118 .

[0072] 18 by current paths I1, I2, I3 and I4, the lowering of the upper surface 460 of the contact portion 456 makes it possible to control the current flow of the operating current I through the contact pair 114 in such a way that the current flowing perpendicular to the contact bridge longitudinal direction 116 in the contact portion 456 and thus in the immediate vicinity of the contact bridge 104 (in the direction 118) can be limited to a maximum length s0. This makes it possible to attenuate the field strength of the magnetic field generated by the current flow in the contact portion 456, and therefore also attenuates the repulsive force on the contact bridge 104 generated by the Lorentz force of such magnetic field.

[0073] 17 and 18, in addition to the special shape of the contact areas 456 in each contact pair 114 of the contact device 400, the fixed contact elements 410 and the corresponding switching contact elements 112 may be arranged offset relative to one another along the contact bridge longitudinal direction 116 (which extends parallel to the arrangement direction of the fixed contacts 402). This means that in the closed position 105, the contact surfaces of the fixed contacts 402 and the contact bridge 104 are formed only by partial areas of the fixed contact elements 410 and the corresponding switching contact elements 112, respectively, and therefore current flow between the contact elements only occurs in this partial area. Here, the switching contact element 112 is offset towards the centre of the contact bridge 104 relative to the corresponding fixed contact element 410, and therefore the contact surface is formed by the outer partial areas of the fixed contact element 410 and the corresponding switching contact element 112 that are closer to the second leg 424 or the end face of the contact bridge 104, respectively.

[0074] 18 by current paths I1, I2, I3, and I4, the offset of the contact elements in the contact pair 114 may be used to control the flow of operating current I through the contact pair 114 such that current flowing perpendicular to the contact bridge longitudinal direction 116 from the fixed contact element 410 to the corresponding switching contact element 112 (or vice versa) can be limited to a maximum length s1 (in direction 116), thereby reducing the field strength of the magnetic field resulting from current flow through the fixed contact element 410 and the switching contact element 112 (parallel to the switching direction 118). Since such a magnetic field also generates a repulsive force on the contact bridge 104 due to the Lorentz force (as well as the current in the first leg 122, 322, 422 of the fixed contact 102, 302, 402), an offset of the corresponding fixed contact element 410 and switching contact element 122 relative to one another can also attenuate the repulsive force acting on the contact bridge 104 in the closed position 105. Optionally, an offset of the contact elements in the contact pair 114 may be provided in the first exemplary contact device 100 and the third exemplary contact device 300. [Explanation of symbols]

[0075] 100, 200, 300, 400 contact devices 102, 102(1), 102(2), 302, 302(1), 302(2), 402 fixed contact 104 Contact Bridge 106, 106(1), 106(2), 306, 306(1), 306(2) Connecting elements 108, 108(1), 108(2), 308, 408 Base 110, 310, 410 Fixed Contact Elements 112 Switching contact element 114 contact pairs 116 Contact bridge longitudinal direction 118 Switching Direction 120 open gap 122, 322 1st leg 124, 324 2nd leg 125, 325 Projected volume 126, 326 opening angle 128, 328 External surface 130, 132 Flow guide parts 134 Ferromagnetic Insert 136 Contact bridge transverse direction 150 Support structure 152 Shaft 154 Overstroke spring 332 Legs 334 Connection 336 Contact protrusion 338, 340 Current-conducting elements 342 void 456 Contact part 458 Connection 460 Top surface of contact area 462 Top of connection I Operating current I1, I2, I3, I4 current paths

Claims

1. A contact arrangement (100, 200, 300, 400) for an electrical switching device, said contact arrangement (100, 200, 300, 400) comprising: two fixed contacts (102, 302, 402) spaced apart from each other along the arrangement direction; a conductive contact bridge (104) movable along a switching direction (118), the conductive contact bridge (104) having a conductive switching contact element (112) for establishing contact with each of the two fixed contacts (102, 302, 402); Equipped with The contact device (100, 200, 300, 400) has at least a closed position (105) and an open position (103), in which in the closed position (105), the switching contact elements (112) of the contact bridge (104) establish electrical contact with the corresponding fixed contacts (102, 302, 402), and in the open position (103), the switching contact elements (110) of the contact bridge (104) have a predetermined contact distance (D) measured in the switching direction relative to the corresponding fixed contacts (102, 302, 402), Each of the two stationary contacts (102, 302, 402) comprises at least a first leg (122, 322, 422) and a second leg (124, 324, 424); each of the two fixed contacts (102, 302, 402) is electrically contactable by at least one of the switching contact elements (112) of the contact bridge (104) at an outer surface (128, 328, 428) of the second leg (124, 324, 424) that is located outside a projected volume (125, 325) spanned by the first leg (122, 322, 422) and the second leg (124, 324, 424); A contact device (100, 200, 300, 400).

2. In the open position (103), the contact bridge (104) is located outside the projected volume (125, 325) spanned by the first leg (122, 322, 422) and the second leg (124, 324, 424). A contact device (100, 200, 300, 400) according to claim 1.

3. each of the two fixed contacts (102, 302, 402) has at least one fixed contact element (110, 310, 410) forming a contact pair (114) with a corresponding switching contact element (112) of the contact bridge (104), the at least one fixed contact element (110, 310, 410) being located at an end of the second leg (124, 324, 424) opposite to the first leg (122, 322, 422); Preferably, in each of the contact pairs (114), the fixed contact element (110, 310, 410) and the corresponding switching contact element (112) are arranged offset relative to each other at least along the arrangement direction. A contact device (100, 200, 300, 400) according to claim 1 or 2.

4. The second legs (124, 324, 424) are aligned parallel to a contact bridge longitudinal direction (116) of the contact bridge (104), which extends parallel to the arrangement direction. A contact device (100, 200, 300, 400) according to any one of claims 1 to 3.

5. each of the first legs (122, 322, 422) is aligned parallel to the switching direction (118) of the contact bridge (104); A contact device (100, 200, 300, 400) according to any one of claims 1 to 4.

6. The first leg (122, 322, 422) and the second leg (124, 324, 424) are each plate-shaped, and the second leg (124, 324, 424) is disposed at a predetermined opening angle to the first leg, preferably perpendicularly. A contact device (100, 200, 300, 400) according to any one of claims 1 to 5.

7. The second leg (324) has at least one leg (332) in which a current (I) flowing through the second leg (324) generates an attractive force on the contact bridge (104) that pushes the contact bridge (104) toward the two fixed contacts (302). A contact device (300) according to any one of claims 1 to 6.

8. The second leg (324) is designed in a stepped manner. The contact device (300) of claim 7.

9. In each of the two stationary contacts (302), the at least one leg (332) of the second leg (324) is arranged parallel to the first leg (322), and a current (I) flowing through the at least one leg (332) parallel to the switching direction (118) in the closed position (105) flows in an opposite direction to a current (I) flowing through the first leg (322) parallel to the switching direction in the closed position (105). A contact device (300) according to claim 7 or 8.

10. In each of the two fixed contacts (302), a distance (r0) between the first leg (322) and the contact bridge (104) is greater than a distance (r1) between the at least one leg (332) of the second leg (324) and the contact bridge (104); A contact device (300) according to any one of claims 7 to 9.

11. In each of the two stationary contacts (302), the length (h1) of the at least one leg (332) of the second leg (324) along the switching direction (118) is at least half the length (h0) of the first leg (322) along the switching direction (118). A contact device (300) according to any one of claims 7 to 10.

12. In each of the two stationary contacts (302), the first leg (322) has at least two current conducting elements (338, 340) separated from each other by an air gap (342) and electrically connected to the second leg (324) separately from each other. A contact device (300) according to any one of claims 6 to 11.

13. the first leg (122, 322, 422) of each of the two fixed contacts (102, 302, 402) is at least partially surrounded by a flow-guiding element (130, 134) that at least partially shields the magnetic field (B, B0) generated in the first leg (122, 322, 422) by a current flow in the direction of the contact bridge (104), respectively; and / or the contact device (100, 200, 300, 400) comprises at least one ferromagnetic flow-inducing element (132, 134) which exerts an attractive force on the contact bridge (104) at least in the closed position (105); A contact device (100, 200, 300, 400) according to any one of the preceding claims.

14. In each of the second legs (424), a contact portion (456) through which the corresponding switching contact element (112) of the contact bridge (104) establishes electrical contact with the second leg (424) is thinner than a connection portion (458) connecting the contact portion (456) to the corresponding first leg (422), the thicknesses of the contact portion (456) and the connection portion (458) being measured parallel to the switching direction (118). A contact device (400) according to any one of claims 1 to 13.

15. 15. An electrical switching device comprising the contact arrangement (100, 200, 300, 400) according to any one of claims 1 to 14 and a drive device designed to move the contact bridge (104) of the contact arrangement (100, 200, 300, 400) between the closed position (105) and the open position (103).

16. A contact arrangement (100, 200, 300, 400) for an electrical switching device, said contact arrangement (100, 200, 300, 400) comprising: two fixed contacts (102, 302, 402) spaced apart from each other along the arrangement direction; a conductive contact bridge (104) movable along a switching direction (118), the conductive contact bridge (104) having a conductive switching contact element (112) for establishing contact with each of the two fixed contacts (102, 302, 402); Equipped with the contact device (100, 200, 300, 400) has at least a closed position (105) and an open position (103), in which in the closed position (105), the switching contact elements (112) of the contact bridge (104) establish electrical contact with the corresponding fixed contacts (102, 302, 402), and in the open position (103), the switching contact elements (110) of the contact bridge (104) have a predetermined contact distance (D) measured in the switching direction relative to the corresponding fixed contacts (102, 302), a contact portion (456) of each of the fixed contacts (102, 302, 402) through which the switching contact element (112) of the contact bridge (104) establishes electrical contact with the corresponding fixed contact (102, 302, 402) is thinner than a portion (458) of the fixed contact (102, 302, 402) adjacent to the contact portion (456), the thicknesses of the contact portion (456) and the adjacent portion (458) being measured parallel to the switching direction (118); A contact device (100, 200, 300, 400).

17. Each of the two fixed contacts (102, 302, 402) has at least one fixed contact element (110, 310, 410) that forms a contact pair (114) together with a corresponding switching contact element (112) of the contact bridge (104), and in each of the contact pairs (114), the fixed contact element (110, 310, 410) and the corresponding switching contact element (112) are arranged offset relative to each other at least along the arrangement direction. A contact device (100, 200, 300, 400) according to claim 16.

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