Switching Device

Abstract

A switching device (100) is described having at least one fixed contact (2) protruding into a switching chamber (11), the at least one fixed contact having a fixed portion (20) and a connecting portion (21), the fixed portion being fixed to the switching chamber, and the connecting portion protruding into a recess (200) of the fixed portion.

Description

[Technical field]

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

[0002] The switching device is especially designed as a remotely operated switch that can be driven by electric current and is electromagnetically actuated. The switching device can be actuated via a control circuit and can switch the 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, in particular power contactors, is the opening and disconnection of battery circuits in motor vehicles, such as motor vehicles that are driven electrically or partly electrically. These can be, for example, purely battery-powered vehicles (BEV: "battery electric vehicle"), hybrid electric vehicles (PHEV: "plug-in hybrid electric vehicle") and hybrid electric vehicles (HEV: hybrid electric vehicle) that can be charged via a power socket or a charging station. In this case, both the positive and negative contacts of the battery are usually disconnected by means of a power contactor. This disconnection takes place both during normal operation, for example when the vehicle is idle, and in the event of a fault, for example in an accident. It is then the main task of the power contactor to switch the vehicle to zero potential and interrupt the current.

[0004] In operation, contactors usually carry large currents. This current is usually carried via power supply lines, such as copper wires, so-called bus bars, or other power supply lines, which are attached to the externally accessible contacts of the contactor, which may also be called pole contacts or terminals. The copper wires or other power supply lines may have a length of up to 200 mm. 2In order to ensure a sufficient, i.e. low-resistance, electrical contact, the current feeders must be attached with a sufficiently high tightening torque, which places high mechanical demands on the pole contacts of the contactor. In addition, during attachment and subsequent operation, shear and leverage forces can arise at the contact points. The contact points should therefore be manufactured from a particularly hard but well-conducting material.

[0005] Particularly good contactors have a switching chamber made of ceramic material, in which the contacts are soldered with hard solder at high temperatures of over 800° C. However, this process carries the risk that the material properties of most of the well-conducting materials that can be used for the contacts change and the material becomes softer. Adequate fixing of the current supply lines is then no longer possible without problems.

[0006] To avoid this problem, materials can be used which are still sufficiently hard to withstand the stresses after the soldering process. However, this usually results in an increase in the cost of the substrate used, since for example special copper alloys have to be used. Furthermore, it is also known to integrate busbar pieces into the contactor, which may allow additional spatially displaced fixing points. However, this has the disadvantages that it leads, for example, to higher costs due to additional parts, a larger final weight of the contactor and an increased electrical contact resistance from fixing point to fixing point.

[0007] US Pat. No. 5,399,433, US Pat. No. 5,499,463, US Pat. No. 5,523,636, US Pat. No. 5,623,367, and US Pat. No. 5,711,663 describe switching devices. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2005-038706 A [Patent Document 2] Japanese Patent Application Publication No. 11-232986 [Patent Document 3] US Patent Application Publication No. 2008 / 0122562 [Patent Document 4] US Patent Application Publication No. 2016 / 0012995 [Patent Document 5] German Patent Invention No. 102019129805 Summary of the Invention [Problem to be solved by the invention]

[0009] At least one objective of certain embodiments is to provide a switching device. [Means for solving the problem]

[0010] This problem is solved by the subject matter according to the independent claims. Advantageous embodiments and developments of the subject matter are set out in the dependent claims and are further evident from the following description and the drawings.

[0011] According to at least one embodiment, the switching device has at least one fixed contact, which may in particular be designed and adapted to connect a supply line of a load circuit which is to be switched on, i.e. closed, and switched off, i.e. disconnected, by the switching device.

[0012] Furthermore, the switching device may have 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 a part of a movable contact of the switching device. The properties and characteristics of the movable contact described below may therefore be corresponding properties and characteristics of the contact bridge and vice versa.

[0013] 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, 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.

[0014] Particularly advantageously, the switching device has at least two fixed contacts, which are arranged separately from one another in the switching device and can be conductively connected to one another or electrically separated from one another via the movable contacts, i.e. in particular the contact bridges, in the manner described above, depending on the state of the movable contacts, i.e. in particular the contact bridges. The contact bridges preferably have an upper side with at least one contact area and a lower side opposite the upper side. In the connected state of the switching device, at least one contact area of ​​the contact bridge is in mechanical contact with at least one fixed contact, in particular with a contact area of ​​the at least one fixed contact. If the switching device has, for example, two fixed contacts, the contact bridges can correspondingly have two contact areas. The features described below for one fixed contact can also apply to several fixed contacts, particularly preferably to each fixed contact, of the switching device.

[0015] In the following, the general term "contacts" may in particular relate to all fixed contacts and to 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 area, 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 for example aluminum oxide, are dispersed.

[0016] According to a further embodiment, the switching device has a housing in which the movable contact and at least one fixed contact or at least two fixed contacts are arranged. The movable contacts can in particular be arranged completely in the housing. Arranging the fixed contacts in the housing can in particular mean that at least the contact areas of the fixed contacts, which in the connected state are in mechanical contact with the movable contacts, are arranged inside the housing. For the 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 the possibility of connection for a current supply line outside the housing.

[0017] According to a further embodiment, the contacts are arranged in a gas atmosphere in the housing. This can mean in particular that the moving contact is arranged completely in the gas atmosphere in the housing and further that 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.

[0018] According to a further embodiment, the switching device comprises a switching chamber. The switching chamber may in particular be arranged inside the housing. In particular, the switching chamber has an interior space. The contacts, i.e. the entire movable contact and a part of the at least one fixed contact, are arranged in the interior space of the switching chamber. Thus, the at least one fixed contact protrudes into the switching chamber. The at least one fixed contact protrudes in particular through an opening into the interior space of the switching chamber. In other words, the at least one fixed contact is located partly inside the switching chamber and partly outside the switching chamber. For example, the switching chamber may have a switching chamber bottom. The switching chamber may further have a switching chamber cover, which together with the switching chamber bottom may enclose the interior space. At least in the region where the at least one fixed contact protrudes into the switching chamber, the switching chamber comprises or consists of a ceramic material, for example aluminum oxide. For example, the at least one fixed contact may protrude through an opening in the switching chamber cover. In this case, the switching chamber cover preferably consists of a ceramic material.

[0019] In the switching chamber, a gas may be present, i.e. at least a portion of the gas atmosphere described above. The gas may preferably contain at least 20% H2, preferably 50% H2. In addition to hydrogen, the gas may contain an inert gas, particularly preferably N2 and / or one or more noble gases.

[0020] According to a further embodiment, the movable contact is movable by a shaft in the switching device. In particular, the movable contact can be movable, for example, by a drive with a shaft, which can be formed in the form of a magnetic drive with a magnet armature or in the form of a motor drive. The shaft is connected to the movable contact at one end in such a way that the movable contact is movable by the shaft, i.e. is likewise moved by the shaft when the shaft moves. The shaft can in particular protrude through an opening in the switching chamber into the inner space of the switching chamber. In the case of a magnetic drive, the magnet armature can be movable by a magnetic circuit in order to trigger the above-mentioned switching operation. For this, the magnetic circuit can have a yoke with 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 at least one fixed contact has two parts which, when coupled, essentially form the at least one fixed contact. In the switching device, the two parts are permanently coupled. Particularly preferably, the two parts are coupled permanently and therefore in such a way that they cannot be separated from each other under normal operating conditions. Furthermore, the at least one fixed contact may have one or more coupling materials which may improve the permanent coupling of the two parts.

[0022] In particular, the at least one fixed contact has as two parts a fixed part and a connecting part, which when joined together essentially form the at least one fixed contact, for example with the exception of at least one connecting material. Particularly preferably, the connecting part and the fixed part are connected to one another at least by engagement and / or by friction forces, for example by a clamping connection or particularly preferably by a screw connection. Furthermore, the connecting part and the fixed part can additionally also be connected to one another by bonding via intermolecular forces.

[0023] The fixed part is intended and adapted to be fixed to the switching chamber, such that the at least one fixed contact is fixed to the switching chamber by the fixed part. In particular, the fixed part may be coupled to the switching chamber by bonding through intermolecular forces. The connecting part is intended and adapted to be connected to an external power supply line, such that the at least one fixed contact may be connected to an external power supply line by the connecting part.

[0024] According to a further embodiment, the fixed part has a recess and the connection part projects into the recess of the fixed part. The recess can be particularly preferably formed as a blind hole, so that the connection part does not project through the fixed part. In particular, the fixed part can be formed in a cup-like shape. The fixed part can have a contact surface in its bottom area opposite the connection part, by means of which the fixed part, and thus the at least one fixed contact, is in mechanical contact with the movable contact in the switched-on state of the switching device. The contact surface is therefore arranged in the switching chamber. The above-mentioned internal mechanical contact with the fixed contact is therefore preferably made via the fixed part, whereas the external mechanical contact with the external current supply line is made via the connection part.

[0025] According to a further embodiment, the connection is accessible outside the switching device. In particular, the connection can have a connection element arranged outside the housing of the switching device. The connection element can be formed, for example, by a stud bolt. Particularly preferably, the stud bolt has an external thread. Alternatively, the connection element can, for example, have a threaded hole in the connection or be a threaded hole.

[0026] Furthermore, the connection part may have a support element from which the connection element extends away. In particular, the connection element may extend away in a direction away from the fixing part as seen from the support element. For this purpose, the support element may particularly preferably have an upper surface facing away from the switching chamber, from which the connection element protrudes.

[0027] The support element can be formed, for example, in the form of a disk-like, particularly preferably circular, disk, from which a connecting element, for example in the form of a stud bolt, projects in the center. The connecting element can be provided for positioning and arranging, as well as for fastening the external current feed line. If the connecting element has an external thread, then for example a fastening nut can be screwed onto said connecting element. The upper surface of the support element can form a support surface for the external current feed line, against which the external current feed line is pressed in the fastened state, i.e. for example when the fastening nut is tightened, in order to achieve the lowest possible electrical contact resistance between the at least one fixed contact and the first current feed line. Thus, the external current feed line can have, for example, a hole through which the connecting element projects, and can further be clamped between the fastening nut screwed onto the connecting element and the support element.

[0028] According to a further embodiment, the connection part has a coupling element, which is preferably arranged on the side of the support element opposite the connection element. The coupling element can be formed, for example, by a stud bolt. In particular, the coupling element can extend in a direction facing the fixing part as seen from the support element. For this purpose, the support element can particularly preferably have an underside facing towards the switching chamber, from which the coupling element protrudes.

[0029] In particular, the coupling element can protrude into the recess of the fastening part and is particularly preferably arranged in the recess. The connection part can particularly preferably be screwed together with the coupling element into the recess. For this purpose, the coupling element can have an external thread and the recess of the fastening part can have an internal thread. Particularly preferably, the connection element and the coupling element each have an external thread with the same thread size.

[0030] According to a further embodiment, the male thread of the coupling element and / or the female thread of the recess have an interference fit before the connection part is screwed into the fastening part. In other words, the female thread of the recess is allowed to be smaller than the male thread of the coupling element. The thread preferably corresponds to the standards DIN 13-1 to DIN 13-52, particularly preferably DIN 13-51 (intermediate tolerance range for gas-tight fits). For example, there may be a fit (intermediate fit) of "M8-5H / 4h". The standard according to DIN 13 generally refers to fine threads, such as threads of type M6, M8, etc. Furthermore, non-metric thread types, such as those according to ASME B1.1, as well as special threads, such as those according to DIN 7756 and valve threads, are also included. By screwing the coupling element into the recess, a stronger threaded connection can be achieved due to the oversized inner diameter, whereby the connection part can be prevented from unintentionally falling off (due to loosening of the threads) from the fastening part.

[0031] According to a further embodiment, a bonding material is arranged between the male thread of the bonding element and the female thread of the recess. The bonding material may comprise or be an adhesive, for example comprising or consisting of an acrylate, such as a methacrylate or a cyanoacrylate.

[0032] According to a further embodiment, a bonding material is arranged in the recess below the connection element. The recess particularly preferably has a depth for this purpose that is greater than the height of the bonding element measured from the underside of the support element, so that when the connection part is fully screwed into the fastening part, a cavity remains below the fastening element, into which the bonding material can be arranged. The bonding material can comprise or consist of an adhesive, for example the adhesive described above, or a soft solder. Here and below, solders having a melting point preferably below 400° C. are referred to as soft solder. The soft solder can, for example, be arranged in the form of a solder pill in the recess of the fastening part already fixed to the switching chamber. After screwing in the connection part, the soft solder can be melted, for example by heating in an oven. The soft solder may be flux-free. Alternatively, the soft solder may be provided with a flux. The flux may, for example, increase the wettability of the soft solder. The soft solder may preferably be lead-free. For example, the soft solder may contain or consist of one or more materials selected from bismuth (Bi), tin (Sn) and antimony (Sb). The mass proportions may be, for example, 25% to 35%, particularly preferably 27% to 31%, for bismuth and tin, respectively, and 50% to 70%, particularly preferably 38% to 46%, for antimony. Furthermore, the soft solder may contain or consist of one or more materials selected from tin (Sn), silver (Ag) and copper (Cu). The mass proportions may be, for example, 50% or more, particularly preferably 85% or more, for tin. The mass proportion of silver may be less than 15%, preferably less than 5%. The mass proportion of copper may be less than 5%, preferably less than 1%. For example, the soft solder may be Sn96.5Ag3.0Cu0.5.

[0033] According to a further embodiment, the support element rests with its underside on the fastening part. The fastening part can have an edge region with an upper surface, on which the underside of the support element rests. The edge region can particularly preferably be formed to surround the recess of the fastening part.

[0034] According to a further embodiment, a bonding material is arranged between the lower surface of the support element and the upper surface of the edge region, for example the bonding material may include or be a soft solder, for example a soft solder as described above.

[0035] According to a further embodiment, the upper surface of the edge region of the fastening part and / or the lower surface of the support element of the connection part has a surface structure, for example knurling and / or roughening. The surface structure can be particularly preferably provided in connection with the bonding material between the lower surface of the support element and the upper surface of the edge region.

[0036] According to a further embodiment, the support elements are welded to the edge region, in particular the support elements can be connected to one another at the edge region by a weld seam outside the contact area formed by the lower surface of the support element and the upper surface of the edge region, which weld seam can particularly preferably be completely circumferential.

[0037] One or more of the above mentioned bonding materials and / or surface structures and / or welds may improve the fastening of the connection part to the fastening part, thereby reducing or even preventing the risk of the connection part unintentionally coming loose from the fastening part.

[0038] The support element and the edge region may particularly preferably have the same outer diameter. The upper surface of the edge region and the lower surface of the support element may, for example, both be ring-shaped and arranged congruently on top of each other. Furthermore, the support element and the edge region may each be arranged partially within an opening of the housing of the switching device. In particular, the contact area between them, i.e. the upper surface of the edge region and the lower surface of the support element, may be arranged inside the opening of the housing.

[0039] According to a further embodiment, the edge region has a fixing edge facing the switching chamber, which is connected to the switching chamber by bonding via intermolecular forces. In other words, the fixing edge is arranged on the opposite side to the top face. In particular, the fixing edge can be connected to the switching chamber by a hard solder, whereby the fixing of at least one fixed contact to the switching chamber takes place. The switching chamber can have a corresponding edge region surrounding an opening through which the at least one fixed contact, i.e. in particular the fixing part, projects into the switching chamber, which edge region can be formed, for example, by a raised ring structure, on which the fixing edge is fixed by hard soldering. Here and below, solders with a melting point of 600° C. or more are referred to as hard solders. For example, solders based on silver and / or copper can be used as hard solders, particularly preferably silver-copper alloys such as Ag72Cu28.

[0040] According to a further embodiment, the connection part and the fixed part are manufactured from the same material. In particular, the connection part and the fixed part may each comprise or consist of the materials generally mentioned above for the contacts, for example metals, preferably copper or copper alloys. In the installed state, i.e. when at least one fixed contact is fixed to the switching chamber, the fixed part may have a lower hardness than the connection part. This can be done by the fact that the fixed part is soldered to the switching chamber by hard solder. Due to the typically high temperatures during hard soldering, for example above 800° C., the material of the fixed part may become softer after hard soldering due to solid-state physical processes. On the contrary, the connection part may maintain its original hardness, since it does not undergo a hard soldering process and is screwed in after hard soldering.

[0041] Thus, in the switching device described herein, the fixed contact or contacts forming the fixing points for the external power supply lines are designed as two-part, with a part, preferably a small part, of each of the fixed contacts being soldered with a hard solder and a second part, which is not subjected to the soldering process, being added afterwards. This has the advantage that there is no weight disadvantage compared to a conventional one-part contact, preferably no or only a small increase in the contact resistance due to the same material, and nevertheless an increase in mechanical strength is achieved compared to a one-part fixed contact. By the measures mentioned above, the second part can be reliably fixed to the soldered first part. Thereby, the fixed contacts and the switching device described herein can be produced cheaply with little or no increase in process costs and higher mechanical loads are possible compared to one-part fixed contacts.

[0042] Further advantages, advantageous embodiments and developments emerge from the exemplary embodiments described below in conjunction with the drawings. [Brief description of the drawings]

[0043] [Figure 1A] 1 is a schematic diagram of an embodiment of a switching device. [Figure 1B] 1 is a schematic diagram of an embodiment of a switching device. [Figure 2A] FIG. 2 is a schematic diagram of a fixed contact of a switching device. [Figure 2B] FIG. 2 is a schematic diagram of a fixed contact of a switching device. [Figure 2C] FIG. 2 is a schematic diagram of a fixed contact of a switching device. [Figure 2D] FIG. 2 is a schematic diagram of a fixed contact of a switching device. [Figure 2E] FIG. 2 is a schematic diagram of a fixed contact of a switching device. [Figure 3A] 5 is a schematic diagram of a method for mounting a fixed contact on a switching chamber cover of a switching device according to a further embodiment; FIG. [Figure 3B]5 is a schematic diagram of a method for mounting a fixed contact on a switching chamber cover of a switching device according to a further embodiment; FIG. [Figure 4] 4 is a schematic diagram of a fixed contact of a switching device according to a further embodiment; [Diagram 5] 4 is a schematic diagram of a fixed contact of a switching device according to a further embodiment; [Figure 6] 4 is a schematic diagram of a fixed contact of a switching device according to a further embodiment; [Figure 7A] 4 is a schematic diagram of a fixed contact of a switching device according to a further embodiment; [Figure 7B] 4 is a schematic diagram of a fixed contact of a switching device according to a further embodiment; [Figure 8A] 4 is a schematic diagram of a fixed contact of a switching device according to a further embodiment; [Figure 8B] 4 is a schematic diagram of a fixed contact of a switching device according to a further embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] 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 with respect to each other 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.

[0045] In Figures 1A and 1B, an embodiment of a switching device 100 is shown, which can be used, for example, to switch high currents and / or high voltages and can be a relay or a contactor, in particular a power contactor. In Figure 1A, a three-dimensional cross-sectional view is shown along a vertical cutting plane. In Figure 1B, a section BB shown in Figure 1A is shown enlarged. The illustrated geometry should be understood to be exemplary only and not limiting, and can be designed in other ways.

[0046] The switching device 100 has contacts 2, 4 in a housing 1, which are also referred to below as switching contacts. The housing 1 is primarily used as a contact protection for the components arranged inside and comprises or consists of a plastic, such as for example PBT or glass-fibre-filled PBT. In the illustrated example, the switching device 100 has as contacts 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, i.e. other numbers of fixed and / or movable contacts, may also be possible. The fixed contacts 2 and / or the contact bridge 4 may comprise or consist of, for example, Cu, a Cu alloy or a mixture of, for example, copper with at least one further metal, such as, for example, Wo, Ni and / or Cr.

[0047] In FIG. 1A the switching device 100 is shown in the switched-off state, in which the contact bridge 4 is separated from the fixed contact 2, so that the contacts 2, 4 are electrically disconnected from one another. To switch the switching device 100 into the switched-on state, the contact bridge 4 shown must be moved upwards towards the fixed contact 2 until it comes into mechanical contact with the fixed contact 2. The switching device 100 comprises a magnetic drive with a movable magnet armature 5, which in the illustrated embodiment essentially performs the switching operation. The magnet armature 5 comprises a magnetic core 6, which for example comprises or consists of a ferromagnetic material. Furthermore, the magnet armature 5 comprises a shaft 7 which is led through the magnetic core 6 and which is firmly connected to the magnetic core 6 at one axial end. At the other axial end opposite the magnetic core 6, the magnet armature 5 comprises the contact bridge 4. The shaft 7 can preferably comprise or be manufactured from special steel.

[0048] To electrically insulate the contact bridge 4 from the shaft 7, an insulator 3, which may also be referred to as a bridge insulator, is arranged therebetween. To help compensate for possible height differences and to ensure sufficient mechanical contact between the fixed contact 2 and the contact bridge 4, a contact spring 34, supported by the insulator 3 and exerting a force on the contact bridge 4 in the direction of the fixed contact 2, is arranged below the contact bridge 4.

[0049] 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, generates an axial movement of the magnetic core 6 and thus of the entire magnet armature 5 until the contact bridge 4 comes into contact with the fixed contact 2. In the illustrated example, the magnet armature 5 moves upwards for this purpose. In that way, the magnet armature 5 moves from a first or idle position, which corresponds to a disconnected or non-connected state and thus a switched-off state, to a second position, which corresponds to an active or connected state and thus a switched-on state. In the active state, the switching contacts are electrically connected to one another.

[0050] To guide the shaft 7 and thus the magnet armature 5, the switching device 100 has 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 has an opening inside which the shaft 7 is guided. Furthermore, a guide sleeve (not shown) for example may be provided in the opening of the yoke 9. When the current in the coil 8 is interrupted, the magnet armature 5 is moved again to the first position by one or more springs 10. In the illustrated example, the magnet armature 5 thus moves downwards again. The switching device 100 is then again in the idle state with the contacts open.

[0051] When the switching contacts are opened, for example, at least one arc may occur, which may damage the contact surfaces of the switching contacts. There may then be a risk that the switching contacts remain "stuck" to one another due to welding caused by the arc and are no longer able to be separated from one another. The switching device 100 is then still in the switched-on state, even though the current in the coil 8 has to be switched off and thus the load circuit disconnected. In order to prevent the occurrence of such an arc, or at least to facilitate the extinction of any arc that does occur, the switching contacts may be arranged in a gas atmosphere, so that the switching device 100 may be designed as a gas-filled relay or gas-filled contactor. In particular, the switching contacts inside the switching chamber 11, formed for example by the switching chamber cover 12 and the switching chamber bottom 13, are arranged in a gas-tight area 14 formed by the hermetically closed parts, the switching chamber 11 being a part of the gas-tight area 14. The gas-tight area 14 completely surrounds the magnet armature 5 and the switching contacts, except for the part of the fixed contact 2 provided for the external connection. The gas-tight region 14, and thus also the inner space 15 of the switching chamber 11, is filled with gas. The gas-tight region 14 is substantially formed by the switching chamber 11, the yoke 9 and a part of the additional wall. The gas that can be filled into the gas-tight region 14 through the gas-filling nozzle 17 in the context of the production of the switching device 100 can be particularly preferably a hydrogen-containing gas, for example with 20% or more H2 in an inert gas or with 100% H2, since this can promote the extinction of the arc. Furthermore, so-called blow-out magnets, i.e. permanent magnets 16, which can lead to an extension of the arc path and thus improve the extinction of the arc, can be present inside or outside the switching chamber 11.

[0052] The switching chamber cover 12 and the switching chamber bottom 13 may be made of or from a ceramic material, for example a metal oxide such as Al2O3. Furthermore, for example for the switching chamber bottom 13, plastics with a sufficiently high temperature stability are also suitable, for example PEEK, PE and / or glass-fiber-filled PBT. Alternatively or additionally, the switching chamber 11 may be at least partially made of ceramics, in particular of the structure (CHO). n Such plastics may also include POM having a relatively low carbon content and a very low tendency to form graphite. In particular, (CHO) n In the case of , the carbon and oxygen contents are identical, which allows mainly gaseous CO and H2 to be generated during thermally induced, in particular arc-induced, decomposition. Additional hydrogen can enhance arc extinction. Particularly preferably, the switching chamber cover 12 is made of a ceramic material and the switching chamber bottom 13 is made of a ceramic material or a plastic, as described above.

[0053] The fixed contact 2 is arranged in an opening 121 of the switching chamber cover 12 and protrudes through the opening 121 into the interior space 15 of the switching chamber 11, so that in particular the contact surface 208 of the fixed contact 2 is arranged in the interior space 15 of the switching chamber 11. The fixed contact 2 is permanently, in particular gas-tightly, attached to the mounting area 122 of the switching chamber cover 12, which extends around the opening 121, by bonding via intermolecular forces. Particularly preferably, the fixed contact 2 is attached to the switching chamber 11 by hard soldering. For this purpose, the fixed contact 2 with the fixing part 20 and the connecting part 21 has an edge area 203 with a fixing edge 205, between which edge area 203 and the mounting area 122 a hard solder (not shown) is arranged. As hard solder, for example a solder based on silver and / or copper can be used, in particular preferably a silver-copper alloy such as Ag72Cu28. The method steps of the method for mounting the fixed contact 2 to the switching chamber cover 12 are explained in relation to Figures 3A and 3B.

[0054] In order to connect the fixed contact 2 to an external power supply line (not shown) of the load circuit, the fixed contact 2 has a connection element 211 formed as a so-called stud bolt, which projects through the opening 101 of the housing 1 as shown in Figs. 1A and 1B and to which an external power supply line, such as for example a supply rail, a so-called bus bar or a cable lug, is attached on the outside of the housing 1. The connection element 211 can have a thread, as will be explained in connection with the following figures, so that the external power supply line can be fixed to the connection element 211 and thus to the fixed contact 2, for example by means of a nut, and pressed against the support element 213. In order to achieve the lowest possible electrical contact resistance between the external power supply line and the fixed contact 2 and to ensure a permanent mechanical connection even in the case of shear and leverage forces which may arise during operation, a sufficiently large tightening torque for screwing the nut onto the connection element 211 is necessary. Therefore, in particular the connection element 211 must have a sufficient mechanical strength. In other words, the material of the connection element 211 must be sufficiently hard. However, as explained at the beginning, in the case of conventional fixed contacts, the hard soldering process for fixing the fixed contacts will result in changes in the material, in particular softening.

[0055] The fixed contact 2 is therefore formed as a two-part contact in the illustrated switching device 100. Further features and embodiments of the fixed contact 2 are explained in conjunction with the following figures.

[0056] In Figures 2A-2E, various views of the fixed contact 2 are shown, which correspond to the two fixed contacts 2 of the switching device 100 according to the embodiment of Figures 1A and 1B. In other words, the fixed contact 2 of the switching device 100 can be formed like the fixed contact 2 according to the description of Figures 2A-2E. In Figures 2A and 2B, a three-dimensional plan view and a three-dimensional cross-sectional view of the fixed contact 2 are shown. In Figures 2C-2E, further various cross-sectional views of the fixed contact 2 or parts thereof are shown. The following description equally relates to Figures 2A-2E.

[0057] As explained in relation to Figures 1A and 1B, the fixed contact 2 has two parts formed by the fixed part 20 and the connecting part 21, which when combined, essentially form at least one fixed contact 2 and are permanently combined in the switching device. Particularly preferably, the connecting part 21 and the fixed part 20 are combined with each other at least by engagement and / or by frictional forces, for example by a clamping connection or particularly preferably by a screw connection. Furthermore, the connecting part 21 and the fixed part 20 can also be combined with each other by bonding through intermolecular forces, as explained in relation to Figures 4 to 8B.

[0058] The fixed part 20 is intended and adapted to be fixed to the switching chamber by hard soldering, as described in relation to Figures 1A and 1B, so that the fixed contact 2 is fixed to the switching chamber by the fixed part 20. The connecting part 21 is intended and adapted to be connected to an external power supply line, as described in relation to Figures 1A and 1B, so that the fixed contact 2 can be connected to an external power supply line by the connecting part 21.

[0059] The fastening part 20 has a recess 200 into which the connecting part 21 projects. The recess 200 is formed as a blind hole, so that the connecting part 21 does not project through the fastening part 20. In particular, the fastening part 20 can be formed in the shape of a cup with a bottom region 201 and a wall region 202 adjoining it. The bottom region 201 is provided with a contact surface 28 on its side opposite the connecting part 21.

[0060] The connection part 21 has a connection element 211 designed as a stud bolt, which, as shown in Figures 1A and 1B, is arranged on the outside of the housing of the switching device and has an external thread 212. The connection element 211 extends from an upper surface 214 of a support element 213 in the direction away from the fixed part 20. The support element 213 is particularly preferably formed in the form of a disk-like, particularly preferably a circular disk, as can be seen, for example, in Figure 2A, from the center of which the connection element projects.

[0061] Furthermore, the connection part 21 has a coupling element 216. The coupling element 216 is arranged on the side of the support element 213 opposite the connection element 211 and is formed as a stud bolt protruding from a lower surface 215 of the support element 213 facing the switching chamber, so that the coupling element 216 extends in a direction facing the fixed part 20 as viewed from the support element 213.

[0062] The coupling element 216 protrudes into and is located in the recess 200 of the fastening part 20. The connecting part 21 is screwed into the recess 200 by means of the coupling element 216. For this purpose, the coupling element 216 has an external thread 217. The recess 200 of the fastening part 20 has a matching internal thread 207 in the wall area 202. For example, the connecting element 211 and the coupling element 216 may each have an external thread 212, 217 with the same thread size, for example size M8. In particular, the external threads 212, 217 may have the same rotational direction and thus may, for example, both be right-hand threads.

[0063] Furthermore, the male threads 217 of the coupling element 216 and / or the female threads 207 of the recess 200 may have an interference fit, as described above in general terms, before screwing the connecting portion 21 into the fixed portion 20, thereby achieving a stronger threaded coupling, thereby preventing unintentional (due to loosening of the threads) removal of the connecting portion 21 from the fixed portion 20.

[0064] After the connection part 21 has been screwed in, the support element 213 preferably rests with its underside 215 on the fastening part 20. The fastening part 20 can for this purpose in particular have an edge region 203 with an upper side 204 on which the underside 215 of the support element 211 rests, so that a best possible electrical contact between the fastening part 20 and the connection part 21 can be achieved. The edge region 203 can particularly preferably be formed so as to surround the recess 200 of the fastening part 20.

[0065] The support element 211 and the edge region 203 may particularly preferably have the same outer diameter.

[0066] The upper surface 204 of the edge region 203 and the lower surface 215 of the support element 211 can, for example, both be formed in the shape of a ring and be arranged congruently on top of each other. As can be seen in Figures 1A and 1B, the support element 211 and the edge region 203 can each be arranged partially within an opening of the housing of the switching device. In particular, the contact area between them, i.e. the upper surface 204 of the edge region 203 and the lower surface 215 of the support element 213, can be arranged inside the opening of the housing.

[0067] As explained in relation to Figures 1A and 1B, the edge region 203 has a fixed edge 205 facing towards the switching chamber, which is joined to the switching chamber by bonding via intermolecular forces. The fixed edge 205 can be separated from the wall region 202, for example, by a surrounding groove 204. Figures 3A and 3B show method steps of a method for attaching the fixed contacts 2 to the switching chamber cover 12, which can be performed for all fixed contacts 2 within the framework of the production of the switching device.

[0068] As shown in FIG. 3A, the fastening parts 20 are inserted into the openings 121 of the switching chamber cover 12 such that the fastening edges 205 are located on the mounting areas 122. The mounting areas 122 can be formed, for example, by raised ring structures in the edge areas of the openings 121. Between the mounting areas 122 and the fastening edges 205, a hard solder 120 is applied, for example a solder based on silver and / or copper, particularly preferably a silver-copper alloy such as Ag72Cu28. The switching chamber cover 12 together with the fastening parts 20 of all the fixed contacts 2 thus arranged is heated, for example in a furnace, so that a gas-tight connection is established between the switching chamber cover 12 and the fastening parts 20 via the melted and resolidified hard solder 120. Subsequently, a connection part 21 can be screwed into each fastening part 20, as shown in FIG. 3B.

[0069] Particularly preferably, the connection part 21 and the fixed part 20 are manufactured from the same material, for example comprising or consisting of a metal, preferably oxygen-free copper or a copper alloy. In the installed state, i.e. when the fixed contact 2 is fixed in the switching chamber, the fixed part 20 may have a lower hardness than the connection part 21 due to the hard soldering process. Due to the typically high temperatures during hard soldering, for example above 800° C., the material of the fixed part 20 may become softer after hard soldering due to solid-state physical processes. In contrast, the connection part 21 may maintain its original hardness, since it does not undergo a hard soldering process and is screwed in after hard soldering.

[0070] While the fixed part 20 is soldered to the switching chamber cover and may soften in the process, the connecting part 21, made of the same material, remains untreated since it is subsequently fixed. The T-shape of the stiffer connecting part 21, visible in the cross-section of Fig. 2E, facilitates a frictional connection with the fixed part 20 and prevents shear forces which may subsequently act on the connecting element 211 from damaging the internal thread 207 of the fixed part 20 through a leverage action. Even with a relatively small tightening torque of about 4 Nm, it has been shown that the electrical contact resistance added by the two-part shape of the fixed contact 2 is negligible.

[0071] In the following figures 4 to 8B further exemplary developments of the fixed contact 2 are shown, which can improve the permanent connection between the fixed part 20 and the connecting part 21. For the sake of clarity, only the components which are described are presented with reference numbers in figures 4 to 8B. The described measures can be used alone or in combination.

[0072] 4, a bonding material 23 may be disposed between the male threads 217 of the bonding element 216 of the connecting part 21 and the female threads 207 of the recess 200 of the fixing part 20, as shown by the dashed area. The bonding material 23 may include an adhesive, for example, including or consisting of an acrylate, such as a methacrylate or a cyanoacrylate, or may be an adhesive. The adhesive may harden after the connecting part 21 is attached to the fixing part 20 and prevent the connecting part 21 from unintentionally loosening.

[0073] As shown in FIG. 5, the bonding material 24 can be arranged in a recess 200 below the bonding element 216 of the connection element 21. For this, the recess 200 particularly preferably has a depth greater than the height of the bonding element 216 measured from the lower surface 215 of the support element 213, so that when the connection part 21 is fully screwed into the fastening part 20, a cavity remains below the bonding element 216, into which the bonding material 24 can be arranged. The bonding material 24 can comprise or consist of an adhesive, for example the adhesive mentioned above, or particularly preferably a soft solder. The soft solder can be arranged, for example, in the form of a solder pill in the recess 200 of the fastening part 20 already fixed in the switching chamber. After the screwing of the connection part 21, the soft solder can be melted, for example by heating in an oven, the temperatures required for this being significantly lower than in hard soldering processes and not resulting in a softening of the connection part 21. The soft solder is preferably lead-free, as described above in the general section, and is for example based on Bi, Sn and / or Sb, or based on Sn and Ag and / or Cu. The soft solder may be flux-free, so that no flux residues remain in the cavity. Alternatively, the soft solder may be provided with a flux. The flux may for example improve the wettability of the soft solder.

[0074] 6, a bonding material 25 can be arranged between the lower surface 215 of the support element 213 of the connection part 21 and the upper surface 204 of the edge region 203 of the fastening part 20. For example, the bonding material 25 can comprise or consist of an adhesive or, particularly preferably, a soft solder as described above.

[0075] Thus, for the development shown in figures 5 and 6, before the connection 21 is screwed into the fixed part 20, a bonding material 24, 25, particularly preferably in the form of a soft solder, can be applied in the recess 200 near the thread or on the outer edge, i.e. on the support surface formed by the upper surface 204 of the edge region 203. For example, after mounting of the connection 21, the solder including the flux can be brought to its melting temperature, preferably below 300 ° C, which leads to melting and subsequently to a strong bond. Due to the low melting point of the soft solder, a reduction in the hardness of the connection 21 is avoided, since in the case of copper and copper alloys this only occurs at temperatures typically above 500 ° C. During operation of the switching device, the temperature of the fixed contact 2 typically remains below 160 ° C, which prevents further melting of the soft solder. Introducing the bonding material 25 on the outer edge has the advantage of increasing the torque required to loosen the soft solder bond.

[0076] 7A and 7B, the upper surface 204 of the edge region 203 of the fastening part 20 and / or the lower surface 215 of the support element 213 of the connection part 21 can have a surface structure 209, 219, e.g. knurling and / or roughening, which can be produced, for example, by sandblasting. The surface structure 209, 219 can particularly preferably be provided in association with a bonding material 25 between the lower surface 215 of the support element 213 and the upper surface 204 of the edge region 203.

[0077] As shown in Figures 8A and 8B, the support elements 213 of the connection part 21 can be welded to the edge region 203 of the fastening part 20. After screwing the connection part 21 to the fastening part 20, the contact edges are welded all around or partially around the edge. In particular, the support elements 213 can be connected to one another at the edge region 203 outside the contact region formed by the underside 215 of the support elements 213 and the upper side 204 of the edge region 203 by a weld seam 26, which is shown by the dashed region in Figure 8A, and which can particularly preferably be completely surrounding. The weld seam 26 can particularly preferably be formed by laser welding. Welding has the advantage of short process times. Furthermore, a high degree of safety can be achieved against unintentional detachment of the connection part 21 from the fastening part 20 during use of the switching device.

[0078] The surfaces of the parts to be joined can be prepared so that the laser beam can effectively introduce energy and reflection of the beam can be prevented. For this purpose, as shown in Fig. 8B, an absorbing element 27 can be arranged in the welding area, which can be formed, for example, by a suitable paint, varnish or roughening.

[0079] The features and embodiments described in relation to 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 relation to the drawings can alternatively or additionally have further features according to the description in general part.

[0080] The invention is not limited thereto by the description based on the examples, but rather includes all novel features and all combinations of features, including in particular 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]

[0081] 1. Housing 2 Fixed contacts 3. Insulators 4 Contact Bridge 5 Magnet Armature 6 magnetic core 7-axis 8 Coils 9. York 10 Spring 11 Switching Chamber 12 Switching chamber cover 13 Bottom of switching chamber 14 Airtight Zone 15. Interior Space 16 Permanent magnets 17 Gas filling nozzle 20 Fixed part 21 Connection 23,24,25 Bonding material 26 Welded seams 27 Absorption Factor 28 Laser Light 34 Contact spring 100 Switching Device 101,102 aperture 122 Mounting Area 123 Fixed edge 120 Hard solder 200 Recess 201 Bottom area 202 Wall area 203 Edge area 204 Top surface 205 Fixed edge 206 Groove 207 Female thread 208 Contact surface 209 Surface structure 211 Connection elements 212 Male thread 213 Supporting elements 214 Top surface 215 Bottom surface 216 Bonding Elements 217 Male thread 219 Surface structure

Claims

1. A switching device (100) having at least one fixed contact (2) projecting into a switching chamber (11), The at least one fixed contact has a fixed portion (20) and a connecting portion (21); The stationary portion is fixed to the switching chamber, said switching device (100).

2. The switching device according to claim 1 , wherein the connecting portion and the fixing portion are made of the same material.

3. The switching device according to claim 2 , wherein the fixed portion has a lower hardness than the fixed portion.

4. The switching device according to any one of claims 1 to 3, wherein the connection portion protrudes into a recess (200) of the fixed portion.

5. The switching device according to claim 4 , wherein the fixing portion is formed in a cup shape, and the recess is formed as a blind hole.

6. The switching device according to any one of claims 1 to 3, wherein the connection comprises a connection element (211) arranged on the outside of a housing (1) of the switching device and formed by a stud bolt.

7. 7. The switching device of claim 6, wherein the connection portion comprises a support element (213), the connection portion extending away from the support element.

8. 8. The switching device according to claim 7, wherein the support element has a lower surface (215) facing towards the switching chamber, and the connection part rests on the fixed part at said lower surface.

9. 9. The switching device according to claim 8, wherein the fixing part has an edge region (203) with an upper surface (204) on which the lower surface of the support element rests.

10. 10. The switching device (100) according to claim 9, comprising a housing (1) in which the switching chamber (11) is arranged, and the upper surface (204) of the edge region (203) and the lower surface (215) of the support element (213) are arranged inside an opening (101) of the housing (1).

11. 10. The switching device according to claim 9, wherein the upper surface of the edge region of the fastening part and / or the lower surface of the support element of the connecting part have a surface structure (209, 219).

12. 12. The switching device according to claim 11, wherein the surface structure is knurled and / or roughened.

13. 10. The switching device according to claim 9, wherein a bonding material (25) is arranged between the lower surface of the support element and the upper surface of the edge region.

14. The switching device according to claim 8 , wherein the support element is welded to the edge region.

15. 9. The switching device of claim 8, wherein the edge region has a fixed edge facing towards the switching chamber, the fixed edge being bonded to the switching chamber by intermolecular forces.

16. The switching device according to any one of claims 1 to 3, wherein the connection part protrudes into a recess of the fixed part with a coupling element (216) and is screwed into the recess with the coupling element.

17. 17. The switching device according to claim 16, wherein the coupling element has an external thread (217) and the recess of the fastening part has an internal thread (207).

18. The switching device according to claim 17 , wherein the male thread and / or the female thread have an interference fit before screwing the connecting part into the fixed part.

19. A switching device according to any one of claims 1 to 3, wherein a bonding material (23) comprising an adhesive is arranged between the male thread and the female thread.

20. A switching device according to any one of the preceding claims, wherein a bonding material (24) comprising a soft solder is arranged in the recess below the connecting element.

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