Switching Device

Abstract

A switching device (100) is described, comprising at least one fixed contact (2, 3), a contact bridge (4) and an upper yoke element (50) in a switching chamber (11), said upper yoke element being fixed to said switching chamber.

Description

[Technical Field]

[0001] A switching device is presented. [Background technology]

[0002] The switching device is particularly designed as a current-driven, electromagnetically actuated, remotely operated switch. The switching device can be operated via a control circuit and can switch a load circuit. In particular, the switching device can be designed as a relay or as a contactor, in particular as a power contactor. Particularly preferably, the switching device can be designed as a gas-filled power contactor.

[0003] One possible application of such switching devices, and in particular power contactors, is the opening and disconnection of battery circuits in motor vehicles, such as electrically or partly electrically powered motor vehicles.

[0004] In their role as safety components, contactors are usually used in combination with fuses between batteries, e.g., lithium-ion batteries, and electric motors; in the event of a malfunction, they must be able to disconnect the power supply from the load. A serious case of battery failure is a short circuit within the battery, which, depending on the battery, can lead to a very rapid discharge with a current in the kiloampere range, and thus several times the nominal current, in a fully charged state. The main task of the contactor in such cases is to carry this very high current for a short period of time, e.g., in the millisecond range, until an upstream fuse can safely disconnect the current or until the current decreases due to the battery's increasing internal resistance.

[0005] Contactors typically include a switching bridge that is movable by a magnetic drive and that conductively connects, for example, two fixed main contacts when the contactor is switched on. However, when a high short-circuit current occurs, the magnetization of the conductor generates a strong Lorentz force that pushes the switching bridge away from the main contacts. This phenomenon is also known as floating. Floating can cause an unintended arc between the main contacts and the bridge, which can burn at very high temperatures and potentially destroy the contactor.

[0006] A magnetic field proportional to the current strength is generated around any conductor through which a current flows. In existing solutions, the magnetic field caused by the current flowing in the switching bridge is concentrated on the iron parts, which then attract each other. The attractive force, also known as the reluctance force, can be used to press the switching bridge harder against the main contacts and prevent the contactor from opening.

[0007] For example, Patent Document 1 describes a floating prevention device in which a switching bridge is biased by a compression spring and held between an insulator and a holding cage. The switching bridge is divided into two current paths in the center. The two paths are surrounded by an iron plate and an iron clamp, with the iron plate locked to the holding cage and the iron clamp fixed to the switching bridge.

[0008] When current flows through the switching bridge, magnetic fluxes are formed around each current path, concentrating on the respective iron parts. An attractive force acts between the iron parts, closing the air gap. This force presses the switching bridge against the main contacts, preventing it from opening. However, the air gap remains unchanged and is predetermined solely by the component design. The maximum holding force, and therefore the maximum short-circuit current, is limited by the following parameters: the force of the compression spring, the cross-section of the iron parts, the holding force of the magnetic drive, and the size of the air gap.

[0009] Patent Documents 2 and 3 similarly describe floating prevention devices, but in which there is no division of the switching bridge into multiple current paths, and therefore only one pair of iron parts is present. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Chinese Utility Model No. 209000835 [Patent Document 2] European Patent No. 2608235 [Patent Document 3] German Patent Application Publication No. 102016206130 Summary of the Invention [Problem to be solved by the invention]

[0011] At least one objective of certain embodiments is to provide a switching device. [Means for solving the problem]

[0012] This problem is solved by the subject matter of the independent claims. Advantageous embodiments and developments of the subject matter are set out in the dependent claims and will become apparent further from the following description and drawings.

[0013] According to at least one embodiment, the switching device comprises at least one fixed contact and at least one movable contact. The movable contact may in particular comprise or be a contact bridge. In other words, the contact bridge may be a movable contact of the switching device or part of a movable contact of the switching device. Therefore, the properties and characteristics of the movable contact described below may be corresponding properties and characteristics of the contact bridge, and vice versa. The switching device may particularly preferably comprise a contact mechanism with a movable contact, i.e. a contact bridge.

[0014] The at least one fixed contact and the at least one movable contact are intended and adapted to switch on and off a load circuit connectable to the switching device. Accordingly, the movable contact, i.e. in particular the contact bridge of the contact mechanism, is movable within the switching device between a disconnected state and a connected state of the switching device such that in the disconnected state of the switching device it is separated from the at least one fixed contact and thus electrically disconnected, and in the connected state it has mechanical contact with the at least one fixed contact and thus electrically connected to said at least one fixed contact. In the following, the connected state is also referred to as the switched-on state of the switching device, and the disconnected state is also referred to as the switched-off state of the switching device.

[0015] Particularly preferably, the switching device has at least two fixed contacts that are arranged separately from one another within the switching device and that can be electrically connected to one another or electrically separated from one another via the movable contacts, particularly the contact bridges, in the manner described above, depending on the state of the movable contacts, particularly the contact bridges. The contact bridges preferably have an upper surface with at least one contact area and a lower surface opposite the upper surface. In the connected state of the switching device, at least one contact area of the contact bridges is in mechanical contact with at least one fixed contact, particularly with a contact area of at least one fixed contact. If the switching device has, for example, two fixed contacts, the contact bridges can accordingly have two contact areas.

[0016] In the following, the general term "contact" may relate in particular to all fixed contacts and to contact bridges or contact arrangements having contact bridges. In particular, the contacts may comprise or consist of a metal, preferably copper or a copper alloy. Furthermore, composite materials are also possible, at least for the contact region, for example in the form of a metal matrix material, preferably comprising or consisting of copper, in which particles comprising or consisting of a ceramic material, such as aluminum oxide, are dispersed.

[0017] According to a further embodiment, the switching device comprises a housing in which a contact mechanism and at least one fixed contact or at least two fixed contacts are arranged. The contact mechanism can, in particular, be completely arranged in the housing. Arranging the fixed contacts in the housing can, in particular, mean that at least the contact area of the fixed contact, which in the connected state is in mechanical contact with the movable contact, is arranged inside the housing. For connection of the conductors of the circuit to be switched by the switching device, the fixed contacts arranged in the housing can be electrically contactable from the outside, i.e., from outside the housing. For this purpose, parts of the fixed contacts arranged in the housing can protrude from the housing and can have connection possibilities for the conductors outside the housing.

[0018] According to a further embodiment, the contacts are arranged in a gas atmosphere in the housing. This can mean in particular that the contact mechanism is arranged completely in the gas atmosphere in the housing and that, in addition, a part of the fixed contact, for example the contact area of the fixed contact, is arranged in the gas atmosphere in the housing. Accordingly, the switching device can particularly preferably be a gas-filled switching device, for example a gas-filled contactor.

[0019] According to a further embodiment, the contacts, i.e. the entire contact mechanism and at least part of the fixed contacts, are arranged in a switching chamber inside the housing. A gas, i.e. at least part of the gas atmosphere described above, can be present in the switching chamber. The gas can advantageously contain at least 20% H2, advantageously 50% H2. In addition to hydrogen, the gas can also contain an inert gas, particularly preferably N2 and / or one or more noble gases.

[0020] According to a further embodiment, the contact bridge is movable by a shaft within the switching device. Particularly preferably, the contact mechanism within the switching device is movable by a shaft. In particular, the contact bridge, particularly preferably the contact mechanism, can be movable by a magnet armature having a shaft. The shaft can be connected at one end directly or indirectly to the contact bridge so that the contact bridge is movable by the shaft, i.e., so that it is similarly moved by the shaft when the shaft moves. Particularly preferably, the shaft can be connected at one end to the contact mechanism so that the contact mechanism is movable by the shaft, i.e., so that it is similarly moved by the shaft when the shaft moves. The shaft can in particular protrude into the switching chamber through an opening in the switching chamber. The magnet armature can be movable by a magnetic circuit to bring about the above-mentioned switching operation. For this purpose, the magnetic circuit can comprise a yoke having an opening through which the shaft of the magnet armature protrudes. The shaft can preferably comprise or consist of special steel. The yoke can preferably comprise or consist of pure iron or a lightly doped iron alloy.

[0021] According to a further embodiment, the contact mechanism comprises a retaining element. The retaining element is, in particular, fixed to the shaft. Furthermore, the retaining element, and therefore the contact mechanism, can be locked to the shaft. This can be possible, for example, by a snap ring or rivet on the shaft. Furthermore, the retaining element, and therefore the contact mechanism, can be screwed onto the shaft. For this purpose, the retaining element can, for example, have a hole with a thread or a modified threaded bushing with a thread, by means of which the retaining element can be screwed onto the thread of the shaft. Furthermore, the retaining element can in this case also be locked to the shaft, for example, by a snap ring and / or a rivet and / or a locking nut. Furthermore, it can also be possible for the shaft to be fixed in the retaining element by a clamp and / or for part of the shaft to be deformed by the material of the retaining element. In this case, the shaft can preferably comprise one or more fixing elements, such as, for example, one or more grooves and / or one or more protrusions, which can extend completely or partially around the shaft.

[0022] According to a further embodiment, the switching device comprises an upper yoke element, which is particularly preferably arranged separately from the contact bridge, particularly preferably from the contact mechanism within the switching device, and in particular can be arranged and fixed so as not to move within the switching device.

[0023] According to a further embodiment, the switching device comprises a lower yoke element in addition to the upper yoke element, in particular the contact arrangement comprises the lower yoke element, which is therefore preferably part of the contact arrangement.

[0024] The upper yoke element, or the upper and lower yoke elements, may each contain or consist of iron. In particular, the upper yoke element, or the upper and lower yoke elements, may each contain or consist of pure iron.

[0025] Preferably, the upper yoke element, in contrast to the lower yoke element, is not part of the contact mechanism and is arranged in the switching chamber independently of the contact mechanism, and therefore, particularly when the contact mechanism comprises a lower yoke element, independently of the lower yoke element. Particularly preferably, the upper yoke element is permanently arranged and locked with respect to its position relative to the at least one fixed contact. The upper yoke element can be fixed to the switching chamber. For example, the upper yoke element can be fixed to the inside of the switching chamber, preferably by soldering or gluing. Alternatively, the upper yoke element can be fixed to the switching chamber by riveting or screwing. Furthermore, the upper yoke element can be held inside the switching chamber by a fixing part, for example made of plastic. For example, the upper yoke element can be fixed in the switching chamber by crimping. In this case, the upper yoke element is inserted somewhat loosely into the switching chamber or part of the switching chamber and can be locked in the switching chamber during assembly, particularly preferably in a form-locking manner, by clamping or crimping. By virtue of the upper yoke element not being part of the contact mechanism, it can be advantageously achieved, in contrast to the prior art described above, that the upper yoke element is not moved together with the contact mechanism during the switching movement, thereby allowing the upper yoke element to be embodied with, for example, larger dimensions than the usual yoke elements of the prior art, since the mass of the upper yoke element is irrelevant to the switching movement.

[0026] According to a further embodiment, the lower yoke element is supported on the holding element so as to be displaceable. Accordingly, the position of the lower yoke element relative to the upper yoke element can be changed, on the one hand, by movement of the lower yoke element within the contact mechanism. Therefore, the gap between the lower yoke element and the upper yoke element can be variable, particularly in the switched-on state of the switching device. On the other hand, in the preferred case where the upper yoke element is fixed to the switching chamber, the position of the lower yoke element can be changed relative to the upper yoke element by movement of the contact mechanism within the switching chamber. Particularly preferably, the lower yoke element is supported on the holding element so as to be displaceable in a direction parallel to the axis.

[0027] According to a further embodiment, the contact bridge is arranged on the holding element. In particular, the contact bridge can be supported on the holding element so as to be displaceable. Particularly preferably, the contact bridge can be supported on the holding element so as to be displaceable in a direction parallel to the axis.

[0028] The fact that an element, in particular the lower yoke element and / or the contact bridge, is displaceably supported on the retaining element may in particular mean that the element can move relative to the retaining element, preferably only in one direction, which may also be called the direction of movement, and at the same time, its degree of freedom of movement is limited by the retaining element. The limitation of the degree of freedom of movement may exist along the direction of movement, so that the mobility along the direction of movement is limited to a certain distance. Preferably, the degree of freedom of movement in directions other than the direction of movement is at least significantly limited, excluding tolerances.

[0029] Particularly preferably, when a lower yoke element is present, the contact bridge, the lower yoke element, and the upper yoke element are supported in pairs so that they can move relative to each other. This means that the contact bridge and the lower yoke element are supported so that they can move relative to each other, because the contact bridge and / or the lower yoke element are movably supported by the holding element. Furthermore, the contact bridge, and if present, the lower yoke element, are supported so that they can move relative to the upper yoke element, which can be achieved, for example, by the contact bridge, and if present, the lower yoke element, being part of a movable contact mechanism, while the upper yoke element is not part of the contact mechanism.

[0030] For example, the holding element may comprise at least one guide element for guiding the contact bridge and / or the lower yoke element. The at least one guide element may be formed, for example, by a guide rail and may enable guidance, and thus a movement direction, in particular along a direction parallel to the axis. Particularly preferably, the holding element comprises multiple guide elements. By means of the guide elements, it is possible to preferably achieve a limitation of mobility in directions other than the desired movement direction. Furthermore, the holding element may comprise at least one stop for limiting the mobility of the contact bridge and / or the lower yoke element. The at least one stop may provide a limitation, in particular along a movement direction, and thus preferably along a direction parallel to the axis. Particularly preferably, the holding element may comprise multiple stops.

[0031] For example, the holding element can include at least one clamping element, which includes at least one guide element and at least one stop and at least partially surrounds the contact bridge and / or the lower yoke element. The at least one clamping element can be arranged, for example, on a base plate of the holding element. In particular, the clamping element can include a stop connected to the base plate via two guide elements, so that the guide element and the stop of the clamping element together with the base plate surround the opening. The contact bridge and / or the lower yoke element can protrude through the opening. Particularly preferably, the holding element includes at least two clamping elements.

[0032] According to a further embodiment, the contact bridge is arranged between the base plate of the retaining element and the upper yoke element. If a lower yoke element is present, the contact bridge is arranged between the lower yoke element and the upper yoke element. In particular, the upper yoke element can be arranged above the contact mechanism when viewed from the axis. The contact bridge can have an upper surface and a lower surface opposite the upper surface, and if present, the lower yoke element is arranged below the contact bridge, thus on the lower surface of the contact bridge, while the upper yoke element is arranged above the contact bridge, thus on the upper surface of the contact bridge.

[0033] According to a further embodiment, the upper yoke element has a recess on its underside facing the contact bridge. The recess may be formed, in particular, as a groove-like recess. The contact bridge may partially protrude into the recess in the switched-on state of the switching device. In particular, the recess may have a width greater than the width of the contact bridge, at least in the region of the recess. For example, the contact bridge may have a narrowed portion, i.e., a region of reduced width, which is at least partially located in the recess of the upper yoke element in the switched-on state of the switching device. Furthermore, the recess may have a depth equal to or substantially equal to the thickness of the contact bridge, at least in the region of the recess. Furthermore, the contact bridge may have a thickness greater than the depth of the recess. The contact bridge may move into the recess due to the switching movement of the contact mechanism during the transition from the switched-off state to the switched-on state of the switching device. Thus, the upper yoke element may at least partially surround the contact bridge in the switched-on state. Preferably, the contact bridge may partially protrude from the recess in the switched-on state of the switching device.

[0034] Furthermore, the contact bridge can be separated from the upper yoke element even in the switched-on state. In other words, the contact bridge cannot have any mechanical contact with the upper yoke element in the switched-on state. Accordingly, an air gap can remain between the upper yoke element and the contact bridge even in the switched-on state.

[0035] According to a further embodiment, the holding element comprises an electrically insulating material. Particularly preferably, the holding element consists of one or more electrically insulating materials, so that the holding element can be electrically insulating. The electrically insulating material can be selected from polymers and ceramic materials, for example, in particular those with the structure (CHO) nThe retaining element can be selected from polyoxymethylene (POM), polybutylene terephthalate (PBT), glass-fiber-filled PBT, and electrically insulating metal oxides such as Al2O3. In particular, the retaining element can electrically insulate the contact bridge, or preferably the contact bridge and contact spring as well as the lower yoke element, from the shaft. This allows the contact bridge to be supported in an electrically insulated state from components of the magnetic drive, i.e., in particular from further components of the magnet armature. This allows the retaining element to simultaneously support the contact bridge and electrically insulate the contact bridge.

[0036] For example, the upper yoke element may be arranged laterally adjacent to at least one fixed contact, where "lateral" here and below means a direction perpendicular to the axis of the magnet armature. Particularly preferably, the switching device comprises two fixed contacts, and the upper yoke element is arranged between the two fixed contacts.

[0037] Furthermore, it may be possible for the retaining element to have a portion, such as the above-mentioned stop, which protrudes into the intermediate space between the at least one fixed contact and the upper yoke element in the switched-on state of the switching device. This may, for example, achieve electrical isolation of the upper yoke element from the at least one fixed contact. In the case of two fixed contacts between which the upper yoke element is arranged, the retaining element may preferably have two portions, such as two stops, each of which may protrude into the intermediate space between one of the fixed contacts and the upper yoke element in the switched-on state of the switching device.

[0038] According to a further embodiment, the contact mechanism further comprises a spring, hereinafter also referred to as a contact spring, arranged on the underside of the contact bridge opposite the upper yoke element. If the contact mechanism also comprises a lower yoke element, the contact spring is arranged on the underside of the contact bridge facing the lower yoke element. The contact spring can press the contact bridge, particularly preferably in the direction of at least one fixed contact. During the switching process of the switching device from the switched-off state to the switched-on state, the magnetic armature, and thus the shaft and contact mechanism, preferably move in a linear motion in the form of a lifting and lowering movement along an axis, which may also be referred to as the vertical direction. Preferably, the shaft and, for example, the magnetic core of the magnetic armature, have a movement clearance for the lifting movement in the vertical direction that is greater than the switching gap formed by the distance between the at least one fixed contact and the contact bridge in the disconnected state. This can be made possible, for example, by the gap, also referred to as the movement gap, between the magnetic core and the yoke of the magnetic circuit in the switched-off state being greater than the switching gap. When the contact bridge strikes the at least one fixed contact, thus completely closing the switching gap, the contact spring can be compressed, allowing the magnetic armature to move further, for example, until the magnetic core contacts the yoke. The magnetic armature with the contact mechanism can therefore be an overstroke system in which the contact bridge is displaceably arranged on the retaining element. For example, the movement gap can be larger than the switching gap by no more than 1 mm, particularly preferably by approximately 0.5 mm. The overstroke compression of the contact spring can increase the contact pressure of the contact bridge against the at least one fixed contact, achieving a certain degree of insensitivity to vibrations and mechanical shocks.

[0039] According to a further embodiment, the contact spring is arranged between the contact bridge and the base plate of the retaining element, or, in the case of an existing lower yoke element, between the contact bridge and the lower yoke element, so that the contact spring presses the contact bridge and the base plate or the contact bridge and the lower yoke element away from each other. The contact spring therefore generates a spring force that resists the lower yoke element's approach to the base plate or the contact bridge. The spring can be supported, preferably directly, on the underside of the contact bridge and the base plate or the lower yoke element. In the second case, the lower yoke element can have a recess into which the spring protrudes and into which the position of the contact spring can be fixed. If the switching device does not have a lower yoke element, the retaining element, in particular the base plate, can have a spring holder that resists the displacement of the contact spring on the retaining element. For example, the spring holder can comprise or be formed from a pin surrounded by a part of the contact spring.

[0040] When a current flows through the contact bridge in the switched-on state of the switching device, a magnetic field is induced in the upper yoke element. In this case, especially in the case of a large current, such as a short-circuit current through the contact bridge, the magnetic field lines may concentrate on the upper surface of the upper yoke element. Since the magnetic field seeks the shortest path to minimize its energy, the magnetic field is strongly compressed through the contact bridge on the underside facing the contact bridge, generating a reluctance force on the contact bridge, which may also be called an anti-floating force because it opposes the stray force. A holding effect can therefore be achieved by the flow of the magnetic field from the upper yoke element through the contact bridge.

[0041] If the switching device includes a lower yoke element, the contact bridge is particularly preferably arranged between the upper and lower yoke elements, as described above. In addition to the aforementioned effect of the upper yoke element on the contact bridge, the yoke element can also capture the magnetic field generated when a current flows through the contact bridge. This means that the two yoke elements are magnetized in this case so that an attractive force is generated between them by the magnetic field generated by the contact bridge through which a current flows. Because the upper yoke element is arranged on the retaining element above the contact bridge and the lower yoke element is arranged below the contact bridge, the attractive force between the yoke elements can pull the lower yoke element upward, i.e., toward the upper yoke element. This effect can enhance the aforementioned retention effect. The contact spring allows the lower yoke element to exert a force on the contact bridge, which in turn pushes the contact bridge further upward, toward the at least one fixed contact. The attractive force acting between the yoke elements is stronger the greater the current flowing through the contact bridge. However, because the contact springs tend to push the lower yoke element away from the contact bridge and therefore away from the upper yoke element, and because the lower yoke element is movably supported by the retaining element, the spring force can be greater than the attractive force between the yoke elements if the current through the contact bridge is sufficiently small. Only when the attractive force between the yoke elements exceeds the spring force of the contact springs can the lower yoke element move toward the upper yoke element, thereby allowing the contact bridge to be pressed more strongly against the at least one fixed contact by the more strongly compressed contact spring. This makes it possible to more effectively counter the above-mentioned floating effect, particularly in the case of short-circuit currents.

[0042] When the switching device is in the switched-on state, as described above, a current can flow through the contact bridge, generating a magnetic flux that induces an attractive force between the contact bridge and the upper yoke element, and, if present, between the lower yoke element and the upper yoke element. If the contact mechanism includes a lower yoke element, the contact mechanism and the upper yoke element are designed such that, when the current is less than a current threshold, the lower yoke element is positioned at a first distance relative to the upper yoke element, and when the current is greater than the current threshold, the lower yoke element is positioned at a second distance relative to the upper yoke element, the second distance being smaller than the first distance. The first and second distances can correspond, for example, to the respective sizes of the air gaps, which therefore decrease when the current threshold is exceeded. Accordingly, the air gap between the lower yoke element and the upper yoke element depends on the current flowing through the contact bridge during operation of the switching device.

[0043] Below the current threshold, the gap, and thus the first distance, may be greater than 1 mm, for example up to 3 mm or even 5 mm. This may therefore be significantly larger than the above-mentioned prior art, in which the gap remains substantially unchanged. After the current threshold is exceeded, the gap, and thus the second distance, may be less than 1 mm, particularly preferably equal to or at least approximately equal to 0. In other words, after the current threshold is exceeded, if the contact mechanism and the upper yoke element are appropriately geometrically designed, it may be possible to pull the lower yoke element relative to the upper yoke element, preferably to the extent that the lower yoke element contacts the upper yoke element or there is a gap of at least less than 1 mm.

[0044] The current threshold can be adjusted by appropriately selecting the spring constant of the contact spring, the geometric design and dimensions of the yoke elements, and the first distance. In particular, the current threshold can be set so that the current corresponding to normal operation of the switching device is below the current threshold. This can be achieved by ensuring that during normal operation, even for small short-circuit currents, the attractive force between the yoke elements is small due to the large air gap with the first distance, so that no increased contact pressure occurs between the contact bridge and the at least one fixed contact, and the contact bridge is held to the at least one fixed contact only by the contact spring. Only when the current threshold is exceeded by a higher short-circuit current does the lower yoke element move toward the upper yoke element, so that the stronger floating force can be compensated for by the attractive force of the yoke element. Thus, as described above, the air gap is variable depending on the current flowing through the contact bridge, and thus the holding force is also variable. It can be achieved that the switching device is only switched "on" when the additional holding force caused by the lower yoke element short-circuits the lower yoke element by closing a magnetic circuit with the upper yoke element.

[0045] In the switching device described herein, the upper yoke element is preferably directly and rigidly fixed to the switching chamber, so it no longer relies on the holding force of the magnetic drive of the switching device, and therefore on the holding force of the coil, as in the prior art solutions described above. Therefore, the upper yoke element of the switching device described herein can withstand large forces, particularly forces greater than 500 N. However, in prior art solutions, the forces induced by the yoke element are typically limited to approximately 100 N, because they can be as large as the holding force of the magnetic drive coil. Therefore, significantly larger short-circuit currents are possible with the switching device described herein. While solutions known in the prior art have typically been shown to be suitable only for short-circuit currents of up to 8 kA for a duration of 5 ms, tests with the switching device described herein have shown that short-circuit currents of up to 16 kA are possible.

[0046] Compared to the complex structures of the prior art, the anti-floating effect described herein can be achieved essentially with only one additional component, namely the upper yoke element. An increased anti-floating effect can be achieved by the additionally provided lower yoke element, as described above, and thus the upper and lower yoke elements, making it possible to switch on the element more precisely. Furthermore, regardless of the presence of the lower yoke element, the arrangement of the upper yoke element in the switching chamber can ensure that the upper yoke element is not moved along with it during switching. This reduces the dynamic mass, which is advantageous for a faster switching process.

[0047] Further advantages, advantageous embodiments and developments will become apparent from the examples described below in conjunction with the drawings. [Brief explanation of the drawings]

[0048] [Figure 1] 1 is a schematic diagram of an example of a switching device. [Figure 2A] 2 is a schematic diagram of various sections and portions of a switching device according to one embodiment; [Figure 2B] 2 is a schematic diagram of various sections and portions of a switching device according to one embodiment; [Figure 2C] 2 is a schematic diagram of various sections and portions of a switching device according to one embodiment; [Figure 2D] 2 is a schematic diagram of various sections and portions of a switching device according to one embodiment; [Figure 2E] 2 is a schematic diagram of various sections and portions of a switching device according to one embodiment; [Figure 2F] 2 is a schematic diagram of various sections and portions of a switching device according to one embodiment; [Figure 3] 10 is a schematic diagram of the effect of the upper yoke element on the contact bridge. [Figure 4A] 5 is a schematic diagram of a part of a switching device according to a further embodiment; [Figure 4B] 5 is a schematic diagram of a part of a switching device according to a further embodiment; [Figure 5A] 2 is a schematic diagram of various sections and portions of a switching device according to one embodiment; [Figure 5B] 2 is a schematic diagram of various sections and portions of a switching device according to one embodiment; [Figure 5C] 2 is a schematic diagram of various sections and portions of a switching device according to one embodiment; [Figure 5D] 2 is a schematic diagram of various sections and portions of a switching device according to one embodiment; [Figure 6A] 5 is a schematic diagram of various sections of a switching device according to a further embodiment; [Figure 6B] 5 is a schematic diagram of various sections of a switching device according to a further embodiment; [Figure 6C] 5 is a schematic diagram of various sections of a switching device according to a further embodiment; [Figure 6D] 5 is a schematic diagram of various sections of a switching device according to a further embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0049] In the examples and figures, identical, similar, or equivalently functioning elements may be respectively provided with the same reference numerals. The illustrated elements and their size ratios relative to one another are not to scale; rather, individual elements, such as layers, components, members, and regions, may be shown exaggeratedly large for better illustration and / or understanding.

[0050] An example of a switching device 100 is shown in Figure 1, which can be used, for example, for switching high currents and / or high voltages and can be a relay or contactor, in particular a power contactor. Figure 1 shows a three-dimensional cross-sectional view taken along a vertical cutting plane. It should be understood that the illustrated geometry is merely exemplary and not limiting, and can be designed in other ways.

[0051] The switching device 100 comprises contacts 1, also referred to below as switching contacts, in a housing (not shown). The housing primarily serves as contact protection for the components arranged inside and comprises or consists of a plastic, such as PBT or glass-fiber-filled PBT. In the illustrated example, the switching device 100 comprises, as contacts 1, two fixed contacts 2 and a movable contact in the form of a contact bridge 4 supported on an insulator 3. The contact bridge 4 is designed as a contact plate. The fixed contacts 2, together with the contact bridge 4, form a switching contact. Instead of the number of contacts shown, other numbers of contacts 1, i.e., other numbers of fixed and / or movable contacts, are also possible. The fixed contacts 2 and / or the contact bridges 4 can comprise or consist of one or more refractory metals, such as Cu, a Cu alloy, Wo, Ni, and / or Cr, or a mixture of the aforementioned materials, for example, a mixture of copper and at least one other metal, such as Wo, Ni, and / or Cr.

[0052] 1, the switching device 100 is shown in the switched-off state in which the contact bridge 4 is separated from the fixed contact 2, and the contacts 2, 4 are therefore electrically disconnected from each other. It should be understood that the illustrated embodiment of the switching contacts and in particular their geometry are purely exemplary and not limiting. Alternatively, the switching contacts can be designed in other ways.

[0053] The switching device 100 comprises a movable magnetic armature 5 which essentially performs a switching movement. The magnetic armature 5 comprises a magnetic core 6 which, for example, comprises or consists of a ferromagnetic material. The magnetic armature 5 further comprises a shaft 7 which runs through the magnetic core 6 and is firmly connected to the magnetic core 6 at one axial end. At the other axial end opposite the magnetic core 6, the magnetic armature 5 comprises a contact bridge 4. The shaft 7 may preferably comprise or be made of special steel.

[0054] To electrically insulate the contact bridge 4 from the shaft 7, an insulator 3, which may also be called a bridge insulator, is arranged between them. To help compensate for possible height differences and ensure sufficient mechanical contact between the fixed contact 2 and the contact bridge 4, a contact spring 34, supported by the insulator 3, is arranged below the contact bridge 4, exerting a force on the contact bridge 4 in the direction of the fixed contact 2.

[0055] The magnetic core 6 is surrounded by a coil 8. A current in the coil 8, which can be connected externally via a control circuit, causes an axial movement of the magnetic core 6, and thus the entire magnetic armature 5, until the contact bridge 4 comes into contact with the fixed contact 2. In the illustrated example, the magnetic armature moves upwards for this purpose. In this way, the magnetic armature 5 moves from a first, i.e., idle position, which corresponds to a disconnected or non-connected state and therefore a switched-off state, to a second, i.e., active, i.e., connected and therefore switched-on state. In the active state, the contacts 1 are electrically connected to each other.

[0056] To guide the shaft 7 and thus the magnetic armature 5, the switching device 100 comprises a yoke 9, which may contain or consist of pure iron or a lightly doped iron alloy and which forms part of the magnetic circuit. The yoke 9 comprises an opening through which the shaft 7 is guided. When the current in the coil 8 is interrupted, the magnetic armature 5 is again moved to the first position by one or more springs 10. Thus, in the illustrated example, the magnetic armature 5 moves downwards again. The switching device 100 is then again in its idle state with the contacts 1 open.

[0057] The direction of movement of the magnetic armature 5, and thus of the contact bridge 4, is hereinafter also referred to as the vertical direction 91. The direction of arrangement of the fixed contacts 2, which is perpendicular to the vertical direction 91, is hereinafter referred to as the longitudinal direction 92. The direction perpendicular to the vertical direction 91 and perpendicular to the longitudinal direction 92, is hereinafter referred to as the transverse direction 93. The directions 91, 92, and 93, which are valid regardless of the switching movement described, are shown in some figures to facilitate orientation. The direction parallel to the plane spanned by the longitudinal direction 92 and the transverse direction 93, and therefore perpendicular to the vertical direction 91, is also called the transverse direction 90.

[0058] For example, when contact 1 opens, at least one arc may occur, potentially damaging the contact surfaces of contact 1. This could result in the contacts 1 becoming "stuck" together and no longer separating due to welding caused by the arc. In this case, switching device 100 remains switched on, even though the current in coil 8 must be switched off and the load circuit must therefore be disconnected. To prevent such arcs from occurring, or at least to facilitate the extinction of any arcs that may occur, contact 1 may be placed in a gas atmosphere, so that switching device 100 may be designed as a gas-filled relay or contactor. In particular, contact 1 within switching chamber 11, formed by switching chamber wall 12 and switching chamber bottom 13, is located within hermetically sealed region 14, which may be part of switching chamber 11. Hermetically sealed region 14 completely surrounds magnetic armature 5 and contact 1, except for the portion of stationary contact 2 provided for external connection. The hermetic region 14, and thus the interior space 15 of the switching chamber 11, is also filled with gas. The hermetic region 14 is essentially formed by the switching chamber 11, the yoke 9, and part of the additional wall. The gas that can be filled into the hermetic region 14 through a gas-filling nozzle during the manufacture of the switching device 100 is preferably a hydrogen-containing gas, for example, containing 20% or more H2 in an inert gas or 100% H2, since this gas can promote arc extinction. Furthermore, so-called blowout magnets, i.e., permanent magnets 16, which can lengthen the arc path and thus improve arc extinction, can be present inside or outside the switching chamber 11.

[0059] The switching chamber wall 12 and the switching chamber bottom 13 can be made of or from a metal oxide, such as Al2O3, for example. Furthermore, plastics with a sufficiently high temperature stability, such as PEEK, PE and / or glass-fiber-filled PBT, are also suitable. Alternatively or additionally, the switching chamber 11 can be made at least in part of a metal oxide, in particular of the structure (CHO). n Such plastics may be characterized by a relatively low carbon content and a very low tendency to form graphite. In particular, (CHO) n In the case of , the same carbon and oxygen content can lead to the evolution of mainly gaseous CO and H2 during thermally induced, and especially arc-induced, decomposition. The additional hydrogen can enhance arc extinction.

[0060] It should be understood that the above-described features of switching device 100 are purely exemplary and not limiting. For example, switching device 100 may be embodied without gas filling instead of the gas-filled contactor embodiment described. In particular, the above description of the example of FIG. 1 helps clarify the functionality of the switching device.

[0061] Below, an embodiment of a switching device 100 is shown, which, compared to the switching device of Figure 1, comprises a contact mechanism 200 and an upper yoke element 50 or a lower yoke element 40 and an upper yoke element 50, which form an anti-floating mechanism.

[0062] 2A-2F illustrate various sections and portions of switching device 100 according to one embodiment. FIG. 2A illustrates a three-dimensional cross-sectional view of a portion of switching device 100 having contact mechanism 200, while FIGS. 2B-2F illustrate different views of switching device 100, and in particular, portions of contact mechanism 200. The following description of switching device 100 applies equally to all of FIGS. 2A-2F. Unless otherwise noted, elements illustrated in FIGS. 2A-2F correspond to elements described in connection with FIG. 1.

[0063] 2A additionally shows the housing 19 of the switching device 100 in comparison with the view of FIG. 1. The contact mechanism 200 is arranged in the switching chamber 11 and comprises the contact bridge 4 and the retaining element 30 and is fixed to the shaft 7. Thereby, the contact mechanism 200 can be moved by the above-mentioned magnetic drive for the execution of the switching movement of the switching device 100.

[0064] Furthermore, the switching device 100 comprises an upper yoke element 50. The upper yoke element 50 may contain or consist of iron. In particular, the upper yoke element 50 may contain or consist of pure iron. The contact bridge 4 is arranged below the upper yoke element 50 by means of a retaining element 30.

[0065] The upper yoke element 50 is not part of the contact mechanism 200 but is arranged in the switching chamber 11 independently of the contact mechanism 200 and therefore independently of the lower yoke element 40. In particular, the upper yoke element 50 is arranged relative to and fixed between the fixed contact 2. As can be seen in FIG. 2A , the upper yoke element 50 and the fixed contact 2 are preferably fixed to the switching chamber 11, in particular to the switching chamber wall 12, which may comprise, for example, a ceramic material to ensure sufficient stability. For example, the upper yoke element 50 and the fixed contact 2 may each be fixed to the switching chamber by soldering. The upper yoke element 50 may have a soldering flange for this purpose. In particular, the upper yoke element 50 may be fixed to the inner surface of the switching chamber 11 by soldering. Alternatively, the upper yoke element 50 may be fixed to the switching chamber 11 by gluing, riveting, screwing, or caulking.

[0066] The retaining element 30 is fixed to the shaft 7. In the illustrated embodiment, the retaining element 30 comprises an electrically insulating plastic, in particular the plastic mentioned in the general section above, and a portion of the shaft 7 is deformed by the material of the retaining element 30, as can be seen in Fig. 2A. The shaft 7 has a fixing element in the form of a groove that extends all around the shaft 7 and into which the material of the retaining element 30 can fit, in order to lock the retaining element 30 and thus the contact mechanism 200. Alternatively, other fixing methods are possible, such as by riveting or screwing.

[0067] The retaining element 30 comprises a base plate 31 fixed to the axis 7. The retaining element 30 comprises clamping elements 32 on the base plate 31 for movably supporting the contact bridge 4, as shown in FIGS. 2B and 2C . The retaining element 30 is particularly preferably formed in one piece and may comprise the materials described in the general section above. The contact bridge 4 is displaceably supported on the retaining element 30 by the clamping elements 32. In particular, the contact bridge 4 is displaceably supported on the retaining element 30 along a movement direction parallel to the axis 7. To guide the contact bridge 4, the retaining element 30 comprises a guide element 36 and a stop 37 forming the clamping element 32. The guide element 36 is formed as a guide rail and allows movement of the contact bridge 4 along the desired movement direction, while the mobility of the contact bridge 4 in other directions is limited by the guide element 36. To limit the mobility of the contact bridge 4, in particular along the movement direction along the axis 7, the retaining element 30 comprises a stop 37 arranged on the side of the guide element 36 opposite the base plate 31. In particular, two guide elements and stops 37 each form clamping elements 32 which together with the base plate 31 form an opening 38. As shown in Fig. 2B, each of the clamping elements 32 surrounds a contact bridge 4. In other words, the contact bridge 4 can protrude through the opening 38 and thereby be guided inside the opening 38 of the clamping elements 32.

[0068] 2A, the retaining element 30 may further be formed in such a way that the stop 37 projects into the intermediate space between the fixed contact 2 and the upper yoke element 50 in the switched-on state of the switching device 100. Thereby, for example, at least partial electrical insulation of the upper yoke element 50 from the fixed contact 2 may be achieved.

[0069] The contact mechanism 200 further comprises a contact spring 34 arranged on the underside of the contact bridge 4 facing the base plate 31. In other words, the contact spring 34 is arranged between the contact bridge 4 and the base plate 31. The retaining element 30, in particular the base plate 31 of the retaining element 30, comprises a spring holder 39 which resists the displacement of the contact spring 34 on the retaining element 30. As shown, the spring holder 39 can, for example, comprise or be formed from a pin surrounded by a part of the contact spring 34.

[0070] The contact spring 34 is embodied as a compression spring. As mentioned above, the contact spring 34 in conjunction with the overstroke can increase the contact pressure of the contact bridge 4 against the fixed contact 2. As the contact spring 34 is arranged between the contact bridge 4 and the base plate 31, the contact spring 34 presses the contact bridge 4 and the base plate 31 away from each other, thereby pressing the contact bridge 4 towards the fixed contact 2.

[0071] The upper yoke element 50 has a recess 52 on its underside facing the contact bridge 4. The recess 52 may be formed, in particular, as a groove-like recess, as can be seen in FIGS. 2A, 2E, and 2F. The contact bridge 4 may protrude at least partially into the recess 52 in the switched-on state of the switching device 100. Furthermore, the contact bridge 4 may have a narrow, e.g., web-shaped, region having a narrower width compared to the contact area of the contact bridge 4, as can be seen, for example, in FIG. 2D in the view of the underside of the contact bridge 4 and the underside of the upper yoke element 50, which narrowed region 45 is located, in the switched-on state of the switching device 100, at least partially within the recess 52 of the upper yoke element 50. In particular, the recess 52 has a width greater than the width of the contact bridge 4, at least in the region of the narrowed region 45. Furthermore, the recess 52 may have a depth less than or substantially equal to the thickness of the contact bridge 4. The contact bridge 4 can move into the recess 52 due to the switching movement of the contact mechanism 200 when the switching device 100 transitions from the switched-off state to the switched-on state. The upper yoke element 50 can therefore at least partially surround the contact bridge 4 in the lateral direction 90, in particular in the transverse direction 93, in the switched-on state of the switching device 100. Figure 2D further shows the position of the contact spring 34.

[0072] Particularly preferably, the contact bridge 4 may have a thickness greater than the depth of the recess 52, as can be seen in particular in Fig. 2E. The upper yoke element 50 may therefore only partially surround the contact bridge 4 in the switched-on state. The contact bridge may therefore partially protrude from the recess 52 in the switched-on state of the switching device 100.

[0073] Furthermore, the contact bridge 4 can particularly preferably be spaced apart from the upper yoke element 50 in the switched-on state. As can also be seen in FIG. 2E, this allows the contact bridge 4 to have no mechanical contact with the upper yoke element 50 in the switched-on state. Accordingly, an air gap can remain between the upper yoke element 50 and the contact bridge 4 even in the switched-on state. By providing such a gap, for example, manufacturing tolerances can be taken into account. Furthermore, it can be ensured that possible burnout, i.e., peeling and uncontrolled deposition of material from the contact 1, which can occur, for example, when a switching arc is formed, does not have undesirable consequences.

[0074] The upper yoke element 50 forms together with the contact bridge 4 an anti-floating mechanism, the function of which is illustrated in relation to Fig. 3 on the basis of a part of the switching device 100 in a cross-section along a cut plane along the vertical direction 91 and the transverse direction 92. In this case, the switching device 100 is shown in the switched-on state, in which a current I flows through the contact bridge 4. In particular, in the case of a short-circuit current, a floating force Flev occurs, which pushes the contact bridge 4 away from the fixed contact, as explained in the general section above. In the absence of the effects explained below, the floating force is only resisted by the spring force of the contact spring.

[0075] 3, in the switching device described herein, when the switching device is in the switched-on state and a current flows through the contact bridge 4, a magnetic field having a magnetic flux MF is induced in the upper yoke element 50. In that case, particularly in the case of a large current, such as a short-circuit current through the contact bridge 4, the magnetic field lines may be concentrated on the upper surface of the upper yoke element 50. In that case, a large thickness of the upper yoke element 50 above the contact bridge 4 may be advantageous. In particular, the upper yoke element 50 may particularly preferably have a larger thickness above the contact bridge 4 in the vertical direction 91 than the contact bridge 4.

[0076] Since the magnetic field seeks the shortest path to minimize energy, the magnetic field is strongly compressed through the contact bridge 4 on the underside facing the contact bridge 4, generating a reluctance force Frel on the contact bridge 4, which can also be called an anti-floating force because it opposes the stray force. A holding effect can therefore be achieved by the flow of the magnetic field from the upper yoke element 50 through the contact bridge 4.

[0077] Modifications and developments of the switching device are explained in connection with the following drawings.

[0078] As shown in Figure 4A, the contact bridge 4 can also be formed without a constriction, and thus have, for example, a simple rectangular parallelepiped shape. Furthermore, as shown in Figure 4B, it is also possible for one, several or all edges of the upper yoke element 50 and / or the contact bridge 4 to be rounded or chamfered.

[0079] Further embodiments of switching device 100 will now be described in connection with the drawings described below. Figures 5A-5D show various sections and portions of switching device 100 according to further embodiments. Figure 5A shows a cross-sectional view of switching device 100 having contact mechanism 200, and Figures 5B-5D show different views of switching device 100, and in particular portions of contact mechanism 200. The following description of switching device 100 applies equally to all of Figures 5A-5D.

[0080] In Figure 5A, compared to the view of Figure 1, the housing 19 of the switching device 100 is additionally shown, but compared to Figure 1, for the sake of clarity, the return spring 10 for returning the magnetic drive device 5 to the switched-off state is not shown. Figure 5B further shows a coil connection 18 for controlling the coil 8. Unless otherwise stated, the elements shown in Figures 5A to 5D correspond to the elements described in connection with Figures 1 and 2A to 3.

[0081] The contact mechanism 200 is arranged in the switching chamber 11 and comprises a contact bridge 4, a retaining element 30 and a lower yoke element 40, and is fixed to the shaft 7, so that the contact mechanism 200 can be moved by the above-mentioned magnetic drive device for performing the switching operation of the switching device 100.

[0082] 2A-2F, the switching device 100 further comprises an upper yoke element 50. The lower yoke element 40 and the upper yoke element 50 may each contain or consist of iron. In particular, the yoke elements 40, 50 may each contain or consist of pure iron. The contact bridge 4 is arranged between the lower yoke element 40 and the upper yoke element 50.

[0083] The upper yoke element 50 is not part of the contact mechanism 200 and is independent of the contact device 200, as described in relation to Figures 2A to 2F, and is therefore positioned and fixed within the switching chamber 11 independent of the lower yoke element 40, as described in relation to Figures 2A to 2F.

[0084] The retaining element 30 is fixed to the shaft 7. In the illustrated embodiment, the retaining element 30 comprises an electrically insulating plastic, in particular the plastic mentioned in the general section above, and a portion of the shaft 7 is deformed by the material of the retaining element 30. The shaft 7 has a fixing element in the form of a groove that extends all around the shaft 7, as can be seen in Fig. 5A, and into which the material of the retaining element 30 can fit, in order to lock the retaining element 30 and thus the contact mechanism 200. Alternatively, other fixing methods are possible, such as by riveting or screwing.

[0085] The holding element 30 comprises a base plate 31 fixed to the shaft 7. On the base plate 31, the holding element 30 comprises clamping elements 32 for movably supporting the contact bridge 4 and the lower yoke element 40. The holding element 30 is particularly preferably formed in one piece and may comprise the materials described in the general section above.

[0086] The contact bridge 4 and the lower yoke element 40 are each displaceably supported by the holding element 30. The position of the lower yoke element 40 with respect to the upper yoke element 50 can therefore change depending on the state of the switching device 100. On the one hand, the relative position of the lower yoke element 40 with respect to the upper yoke element 50 can be changed by displacement of the lower yoke element 40 on the holding element 30 and thus within the contact mechanism 200. Therefore, as will be explained in more detail below, the gap between the lower yoke element 40 and the upper yoke element 50, particularly in the switched-on state of the switching device 100, can be variable. Furthermore, the position of the lower yoke element 40 with respect to the upper yoke element 50 can be changed by movement of the contact mechanism 200 within the switching chamber 11. Particularly preferably, the lower yoke element 40 is supported by the holding element 30 in such a way that it is displaceable along a movement direction parallel to the axis 7, and thus extending along the vertical direction 91. Furthermore, the contact bridge 4 is also supported on the holding element so as to be displaceable along a movement direction parallel to the axis 7. Thus, the contact bridge 4 and the lower yoke element 40, and the contact bridge 4 and the upper yoke element 50 can also be displaceable relative to one another.

[0087] The lower yoke element 40 can be placed on the base plate 31, at least in the switched-off state of the switching device 100 shown in Figures 5A to 5C. For secure positioning, the lower yoke element 40 can be provided on the side facing the base plate 31 with grooves, for example on the edge side, into which the protrusions of the base plate 31 can engage.

[0088] To guide the contact bridge 4 and the lower yoke element 40, the holding element 30 comprises a guide element 36 and a stop 37. The guide element 36 is embodied as a guide rail and allows movement of the contact bridge 4 and the lower yoke element 40 along the desired displacement direction, while the mobility of the contact bridge 4 and the lower yoke element 40 in other directions is limited by the guide element 36. To limit the mobility of the contact bridge 4 and the lower yoke element 40, particularly along the movement direction along the axis 7, the holding element 30 comprises a stop 37 arranged on the side of the guide element 36 opposite the base plate 31. In particular, two guide elements and two stops 37 form clamping elements 32, each of which forms an opening 38 with the base plate 31. As shown in FIG. 5C , each of the clamping elements 32 surrounds the contact bridge 4. In other words, the contact bridge 4 can protrude through the opening 38 and thereby be guided inside the opening 38 of the clamping element 32. In the illustrated embodiment, the lower yoke elements 40 are guided between the clamping elements 32. Alternatively or additionally, however, the lower yoke elements 40 can also be formed so as to protrude through the openings 38 and be guided within the openings 38 and thus be surrounded by the clamping elements 32.

[0089] 5B, the retaining element 30 may further be formed in such a way that the stop 37 projects into the intermediate space between the fixed contact 2 and the upper yoke element 50 in the switched-on state of the switching device 100. Thereby, for example, at least partial electrical insulation of the upper yoke element 50 from the fixed contact 2 may be achieved.

[0090] The contact mechanism 200 further comprises a contact spring 34 arranged on the underside of the contact bridge 4 facing the lower yoke element 40. In other words, the contact spring 34 is arranged between the contact bridge 4 and the lower yoke element 40, in comparison with the embodiment of FIGS. 2A to 2F. The contact spring 34 is embodied as a compression spring. As described above, the contact spring 34, in conjunction with the overstroke, can increase the contact pressure of the contact bridge 4 against the fixed contact 2. Since the contact spring 34 is arranged between the contact bridge 4 and the lower yoke element 40, the contact spring 34 tries to push the contact bridge 4 and the lower yoke element 40 away from each other. The contact spring 34 therefore generates a spring force that opposes the approach of the lower yoke element 40 to the contact bridge 4. The contact spring 34 can be supported, in particular, directly on the underside of the contact bridge 4 and / or directly on the lower yoke element 40, as shown. The lower yoke element 40 has a recess 41 into which the contact spring 34 protrudes, so that the position of the contact spring 34 can be fixed.

[0091] The upper yoke element 50 has a recess 52 on its underside facing the contact bridge 4. The recess 52 may be formed, in particular, as a groove-like recess, as shown. The contact bridge 4 may protrude at least partially into the recess 52 in the switched-on state of the switching device 100. Furthermore, as already explained in connection with the embodiment of FIGS. 2A to 2F , the contact bridge 4 may have a narrow, e.g., web-shaped, region 45, i.e., a narrower region compared to the contact area of the contact bridge 4, as can be seen in the view of the undersides of the contact bridge 4 and the upper yoke element 50 in FIG. 5D , which narrowed region 45 is arranged, in the switched-on state of the switching device 100, at least partially within the recess 52 of the upper yoke element 50. In particular, the geometric configuration of the contact bridge 4 and the upper yoke element 50 may be as explained in connection with FIGS. 2A to 4B .

[0092] Alternatively or additionally to the illustrated embodiment, the lower yoke element 40, which in the illustrated embodiment is formed like a plate, may also have a recess corresponding to the recess 52, while the upper yoke element 50 may have a flat lower surface. Furthermore, it may also be possible for both yoke elements 40, 50 to have respective recesses through which each of the yoke elements 40, 50 partially surrounds the contact bridge 4 from below or above at a position corresponding to the contact bridge 4.

[0093] The contact arrangement 200, in particular the lower yoke element 40 and the upper yoke element 50, form a further anti-floating mechanism in addition to the effect explained in connection with Figure 3, the function of which will be explained in connection with Figures 6A to 6D on the basis of the switching device 100 in cross-sections according to cutting planes along the vertical direction 91 and the longitudinal direction 93 (Figures 6A, 6C) and along the vertical direction 91 and the transverse direction 92 (Figures 6B, 6D). In this case, the switching device 100 is shown in the switched-on state in which a current I flows through the contact bridge 4, as shown in Figures 6A and 6C.

[0094] In the switched-off state of the switching device 100, the moving part of the switching device 100 is in a lower, resting position, as shown in particular in FIG. 5A . Electrical contact between the fixed contact 2 and the contact bridge 4 is broken in this state. The contact spring 34 biases the contact bridge 4 and the lower yoke element 40, holding them in place within the cage of the retaining element 30 formed by the base plate 31 and the clamping element 32. When the switching device 100 is switched on, a control current flows through the coil 8 of the magnetic drive, causing the magnetic core 6 to move upward. This also causes the contact mechanism 200, including the contact bridge 4, the retaining element 30, the contact spring 34, and the lower yoke element 40, to move upward via the shaft 7, thereby pressing the contact bridge 4 against the fixed contact 2. The magnetic core 6, the shaft 7, the retaining element 30, the contact spring 34, and the lower yoke element 40 then move further upward until the magnetic core strikes the yoke of the magnetic drive. This further compresses the contact spring 34, ensuring sufficient contact force between the contacts 1 to permanently carry the nominal current. This state is the normal state of the switching device 100 in the switched-on state and is shown in Figures 6A and 6B.

[0095] A current I flowing through the contact bridge 4 induces a magnetic flux MF in the yoke elements 40, 50. The magnetization generates a reluctance force Frel, or attractive force, between the yoke elements 40, 50, which is opposite to the spring force Fs of the contact spring 34. The greater the current I flowing through the contact bridge 4, the stronger the acting reluctance force Frel, or attractive force. However, because the contact spring 34 tries to push the lower yoke element 40 away from the contact bridge 4 and therefore away from the upper yoke element 50, if the current I is sufficiently small, the spring force Fs can be greater than the reluctance force Frel between the yoke elements 40, 50. In this case, which is normal operation, the moving parts remain in the position shown in Figures 6A and 6B.

[0096] Between the yoke elements 40, 50 there is an air gap L, which corresponds to a first distance L1 between the yoke elements 40, 50 from each other. The first distance L1 is particularly preferably greater than 1 mm and may in particular be several millimeters, for example 3 mm or even 5 mm.

[0097] Through appropriate selection of the spring constant of the contact spring 34, the geometric design and size of the yoke elements 40, 50, and the first distance L1, a current threshold for the current I can be set. Up to this current threshold, the state shown in FIGS. 6A and 6B is maintained, and the air gap L remains open in the manner shown. The current threshold is preferably above the nominal current and, particularly preferably, can also exceed smaller short-circuit currents. For example, the current threshold can be several kiloamperes, approximately 5 kA. In the low short-circuit current range below the current threshold, the floating force F, which pushes the contact bridge 4 away from the fixed contact 2, is small, so that only the contact spring 34 can exert a force to hold the contact bridge 4 to the fixed contact 2.

[0098] When the current I through the contact bridge 4 finally exceeds the current threshold, a situation exists in which an increased short-circuit current flows through the contact 1, and the reluctance force Frel also increases proportionally to the current I and exceeds the spring force Fs. This causes the lower yoke element 40 to move upward, i.e., toward the upper yoke element 50. This reduces the air gap L, which further increases the magnetic flux MF. This causes the reluctance force Frel to exponentially increase beyond the spring force Fs. The contact spring 34 is further compressed, preferably until the lower yoke element 40 contacts the underside of the contact bridge 4 or the underside of the upper yoke element 50. The air gap L corresponds to a second, smaller distance L2 between the yoke elements 40, 50, as shown in FIGS. 6C and 6D, which in this case is minimal and may even be equal to or approximately equal to zero. Here, the contact pressure is at a maximum, in particular so great that the reluctance force Frel further exceeds the floating force Flev and the contact bridge 4 can be pressed further against the fixed contact 2. Only above a maximum short-circuit current, which can for example be in the range of 16 kA or more, the yoke elements 40, 50 are saturated by the magnetic flux MF and the floating force Flev can exceed the reluctance force Frel, so that the contact bridge 4 is lifted off the fixed contact 2.

[0099] The air gap L is therefore variable as explained depending on the current I flowing through the contact bridge 4, and therefore also the holding force. It can be achieved that the additional holding force by the yoke elements 40, 50 is "switched on" only in the event of a short circuit above a current threshold, so that the switching device 100 can carry larger short circuit currents compared to known solutions.

[0100] The features and embodiments described in connection with the drawings can be combined with each other according to further embodiments, even if not all combinations are explicitly described. Furthermore, the embodiments described in connection with the drawings can alternatively or additionally have further features according to the description in general part.

[0101] The present invention is not limited by the description based on the examples, but rather includes all novel features and all combinations of features, including all combinations of features in the claims, even if the feature or combination itself is not explicitly set out in the claims or examples. [Explanation of symbols]

[0102] 1 Contact 2 Fixed contacts 3. Insulators 4 Contact Bridge 5 Magnet Armature 6 magnetic core 7 axes 8 coils 9 York 10 springs 11 Switching Chamber 12 Switching chamber wall 13 Bottom of switching chamber 14 Airtight Zone 15 Interior Space 16 Permanent Magnets 18 Coil connection 19 Housing 30 holding elements 31 Base Plate 32 clamping elements 34 Contact spring 36 Guide Elements 37 Stop part 38 Aperture 39 Spring holder 40 Lower Yoke Element 41 Depression 45 Stenosis 50 Upper yoke element 51 Soldering flange 52 depression 60 void 90 horizontal 91 vertical direction 92 Longitudinal 93 Transverse 100 Switching Device 200 Contact mechanism I current Flev Fs spring force Frel reluctance force L1,L2 distance MF magnetic flux

Claims

1. A switching device (100) comprising at least one fixed contact (2, 3), a contact bridge (4) and an upper yoke element (50) in a switching chamber (11), the upper yoke element is fixed to the switching chamber; the upper yoke element has a recess (52) on its underside facing the contact bridge, the contact bridge at least partially protruding into the recess in the switched-on state of the switching device; The switching device (100) has at least one of the following characteristics: the contact bridge has a constriction (45), which is arranged at least partially in the recess of the upper yoke element in the switched-on state of the switching device; ◆ the contact bridge has a thickness greater than the depth of the recess; The switching device comprises a contact mechanism (200); the contact mechanism comprises a holding element (30) movable by a shaft (7) and fixed to the shaft, and the contact bridge displaceably supported on the holding element, the holding element comprising at least one clamping element (32), the clamping element comprising at least one guide element (36) for guiding the contact bridge and at least one stop (37) for limiting the mobility of the contact bridge, and at least partially surrounding the contact bridge; and / or The contact mechanism further comprises a lower yoke element (40) displaceably supported on the retaining element;

2. The switching device of claim 1 , wherein the upper yoke element is disposed laterally adjacent to the at least one fixed contact.

3. 3. A switching device according to claim 1, comprising two fixed contacts, the upper yoke element being disposed between the two fixed contacts.

4. 2. The switching device according to claim 1, wherein the contact bridge partially protrudes from the recess in the switched-on state.

5. 2. The switching device according to claim 1, wherein the contact bridge is spaced apart from the upper yoke element in a switched-on state.

6. 2. The switching device according to claim 1, wherein the upper yoke element has a thickness above the contact bridge that is greater than the thickness of the contact bridge.

7. 2. The switching device according to claim 1, wherein the upper yoke element is fixed to the switching chamber by soldering, riveting, screwing, gluing or caulking.

8. 2. The switching device according to claim 1, wherein the at least one stop protrudes into an intermediate space between the at least one fixed contact and the upper yoke element in a switched-on state of the switching device.

9. 2. The switching device according to claim 1, wherein the contact mechanism comprises a contact spring (34), the contact spring being arranged on a lower surface of the contact bridge opposite the upper yoke element and urging the contact bridge toward the at least one fixed contact.

10. 10. The switching device according to claim 9, wherein the contact spring is supported directly on the underside of the contact bridge and / or directly on the retaining element.

11. 11. A switching device according to claim 9 or 10, wherein the retaining element comprises a spring holder (39) which comprises a pin which opposes the displacement of the contact spring on the retaining element and is surrounded by a part of the contact spring.

12. The gap (L) between the lower yoke element and the upper yoke element depends on the current flowing through the contact bridge during operation of the switching device, The contact bridge is disposed between the lower yoke element and the upper yoke element. The switching device of claim 1 .

13. 13. The switching device according to claim 12, wherein a contact spring (34) is arranged between the contact bridge and the lower yoke element, the contact spring urging the contact bridge and the lower yoke element away from each other.

14. A switching device (100) comprising at least one fixed contact (2, 3), a contact bridge (4) and an upper yoke element (50) in a switching chamber (11), The upper yoke element is fixed to a switching chamber wall (12) of the switching chamber; the switching chamber wall (12) comprises a ceramic material; The switching device (100) is configured such that the upper yoke element is held inside the switching chamber by a fixing part made of plastic.

Images