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 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, in particular power contactors, is the opening and disconnection of battery circuits in motor vehicles, such as electrically or partially electrically powered motor vehicles. These can be, for example, purely battery-powered vehicles (BEVs: "battery electric vehicles"), hybrid electric vehicles (PHEVs: "plug-in hybrid electric vehicles") and hybrid electric vehicles (HEVs: "hybrid electric vehicles") 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 using a power contactor. This disconnection occurs both during normal operation, for example, when the vehicle is idling, and in the event of a fault, for example, in an accident. The main role of the power contactor is to switch the vehicle to zero potential and interrupt the current.

[0004] During operation, contactors typically carry large currents. This current is typically 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 be 200 mm long or longer. 2In order to ensure a sufficient, i.e. low-resistance, electrical contact, the power feeder 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 lever forces can arise at the contact points. Therefore, the contact points should be manufactured from a particularly hard but well-conducting material.

[0005] Particularly high-performance contactors have switching chambers made of ceramic material, into which the contacts are soldered using hard solder at high temperatures above 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 fixation of the power supply lines is then no longer possible without problems.

[0006] To avoid this problem, materials can be used that 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, because, for example, special copper alloys must be used. Furthermore, it is also known to integrate busbar pieces into the contactor, which may allow for additional, spatially displaced fixing points. However, this has the disadvantages of, for example, leading to higher costs due to additional parts, a greater final weight of the contactor, and an increase in the electrical contact resistance from fixing point to fixing point.

[0007] Patent Documents 1, 2, 3, 4 and 5 describe switching devices. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-038706 [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 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.

[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 the feed lines of a load circuit that 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. Therefore, the properties and characteristics of the movable contact described below may 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 within the switching device and can be electrically 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 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 bridge is in mechanical contact with at least one fixed contact, in particular with a contact area of ​​at least one fixed contact. If the switching device has, for example, two fixed contacts, the contact bridge may correspondingly have two contact areas. The features described below for one fixed contact may also apply to multiple fixed contacts of the switching device, in particular preferably to each fixed contact.

[0015] In the following, the general term "contacts" may relate in particular to all fixed contacts and 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.

[0016] According to a further embodiment, the switching device has a housing in which a movable contact and at least one fixed contact or at least two fixed contacts are arranged. The movable contact may, in particular, be arranged completely in the housing. Arranging the fixed contact in the housing may, in particular, mean that at least the contact area of ​​the fixed contact, which is in mechanical contact with the movable contact in the connected state, is arranged inside the housing. For connection of the conductors of the circuit to be switched by the switching device, the fixed contact arranged in the housing may be electrically contactable from the outside, i.e., from outside the housing. For this purpose, a part of the fixed contact arranged in the housing may protrude from the housing and may have the possibility of connection for a power 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 movable contact is arranged completely in the gas atmosphere in the housing, and that a part of the fixed contact, for example the contact area of ​​the fixed contact, is also 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 has a switching chamber. The switching chamber may be arranged in a housing. In particular, the switching chamber has an interior space. The contacts, i.e., the entire movable contact and a portion of the at least one fixed contact, are arranged in the interior space of the switching chamber. Thus, at least one fixed contact protrudes into the switching chamber. The at least one fixed contact protrudes into the interior space of the switching chamber, in particular through an opening. In other words, the at least one fixed contact is located partially inside the switching chamber and partially 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 may contain or consist of a ceramic material, such as 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] A gas, i.e., at least a portion of the gas atmosphere described above, may be present in the switching chamber. 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 within the switching device by a shaft. In particular, the movable contact can be movable, for example, by a drive having 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 coupled to the movable contact at one end so that the movable contact is movable by the shaft, i.e., so that it is also moved by the shaft when the shaft moves. The shaft can in particular protrude into the interior space of the switching chamber through an opening in the switching chamber. In the case of a magnetic drive, the magnet armature can be movable by a magnetic circuit to trigger the above-mentioned switching operation. For this purpose, the magnetic circuit can have a yoke with an opening through which the shaft of the magnet armature protrudes. The shaft can preferably include or consist of special steel. The yoke can preferably include 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 that, 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 permanently coupled, and therefore cannot be separated from each other under normal operating conditions. Furthermore, the at least one fixed contact may have one or more bonding materials that can improve the permanent coupling of the two parts.

[0022] In particular, the at least one fixed contact has two parts, a fixed part and a connecting part, which, when joined, 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 joined to one another at least by engagement and / or frictional forces, for example by a clamping connection or, particularly preferably, by a screw connection. Furthermore, the connecting part and the fixed part can additionally be joined 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 can 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 can be connected to the external power supply line by the connecting part.

[0024] According to a further embodiment, the fixed part has a recess, and the connecting part protrudes into the recess of the fixed part. The recess can be particularly preferably formed as a blind hole, so that the connecting part does not protrude through the fixed part. In particular, the fixed part can be formed in a cup shape. The fixed part can have a contact surface in its bottom area opposite the connecting part, by means of which the fixed part, and thus the at least one fixed contact, comes into mechanical contact with the movable contact when the switching device is in the switched-on state. The contact surface is therefore arranged within the switching chamber. The above-mentioned internal mechanical contact with the fixed contact is therefore preferably made via the fixed part, while the external mechanical contact with the external power supply line is made via the connecting 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 have, for example, 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 when viewed 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, particularly preferably a circular disk, from which a connecting element, for example in the form of a stud bolt, protrudes in the center. The connecting element can be provided for positioning and arranging, as well as for fastening the external power supply line. If the connecting element has an external thread, for example, a fastening nut can be screwed onto the connecting element. The upper surface of the support element can form a support surface for the external power supply line, and in order to achieve the lowest possible electrical contact resistance between the at least one fixed contact and the first power supply line, the external power supply line is pressed against the support surface in the fastened state, i.e., when the fastening nut is tightened, for example. Thus, the external power supply line can have, for example, a hole through which the connecting element protrudes, and can be clamped between the support element and a fastening nut screwed onto the connecting element.

[0028] According to a further embodiment, the connection part has a coupling element, which is preferably arranged on the support element opposite the connecting element. The coupling element can be formed, for example, by a stud bolt. In particular, the coupling element can extend, as viewed from the support element, toward the fixing part. For this purpose, the support element can particularly preferably have an underside facing 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 connecting part can particularly preferably be screwed into the recess together with the coupling element. 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 connecting element and the coupling element each have an external thread with the same thread size.

[0030] According to a further embodiment, the external thread of the coupling element and / or the internal thread of the recess have an interference fit before the connection part is screwed into the fastening part. In other words, the internal thread of the recess is allowed to be smaller than the external 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 fit). For example, an "M8-5H / 4h" transition fit may exist. The DIN 13 standard generally refers to fine threads, such as threads of types 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, thereby preventing the connection part from unintentionally coming off the fastening part (due to loosening of the threads).

[0031] According to a further embodiment, a bonding material is arranged between the external thread of the bonding element and the internal thread of the recess, which 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 disposed in the recess below the connection element. For this purpose, the recess particularly preferably has a depth 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 disposed. The bonding material can comprise or consist of an adhesive, such as the adhesive described above, or a soft solder. Here and below, solders with a melting point preferably below 400°C are referred to as soft solder. The soft solder can be disposed, for example, in the form of a solder pill in the recess of the fastening part already secured 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 can be provided with a flux. The flux can, for example, improve the wettability of the soft solder. The soft solder can 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 of bismuth and tin may be, for example, 25% to 35%, particularly preferably 27% to 31%, and of antimony may be, for example, 50% to 70%, particularly preferably 38% to 46%. Furthermore, the soft solder may contain or consist of one or more materials selected from tin (Sn), silver (Ag), and copper (Cu). The mass proportion of tin may be, for example, 50% or more, particularly preferably 85% or more. 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 comprise or be a soft solder, such as 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 connecting part has a surface structure, for example knurling and / or roughening, which can particularly preferably be 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 surrounding.

[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 fixed part, thereby reducing or even preventing the risk of the connection part unintentionally loosening from the fixed 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 flush with each other. Furthermore, the support element and the edge region may each be partially arranged within an opening in 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 in the housing.

[0039] According to a further embodiment, the edge region has a fixing edge facing the switching chamber, which is bonded to the switching chamber by intermolecular forces. In other words, the fixing edge is located on the side opposite the upper surface. In particular, the fixing edge can be bonded to the switching chamber by hard solder, thereby fixing at least one fixed contact to the switching chamber. The switching chamber can have a corresponding edge region surrounding an opening through which the at least one fixed contact, i.e., the fixing portion, protrudes into the switching chamber, the edge region being formed, for example, by a raised ring structure, onto which the fixing edge is fixed by hard soldering. Here and below, solders with a melting point of 600°C or higher are referred to as hard solders. For example, silver- and / or copper-based solders, particularly preferably silver-copper alloys such as Ag72Cu28, can be used as hard solders.

[0040] According to a further embodiment, the connecting portion and the fixing portion are made of the same material. In particular, the connecting portion and the fixing portion may each comprise or consist of the materials generally described above for the contacts, such as metal, preferably copper or a copper alloy. In the installed state, i.e., when at least one fixed contact is fixed to the switching chamber, the fixing portion may have a lower hardness than the connecting portion. This can be achieved by soldering the fixing portion to the switching chamber with a hard solder. Due to the typically high temperatures during hard soldering, e.g., above 800°C, the material of the fixing portion may become softer after hard soldering due to solid-state physical processes. In contrast, the connecting portion may maintain its original hardness because it does not undergo a hard soldering process and is screwed in after hard soldering.

[0041] Therefore, in the switching device described herein, one or more fixed contacts forming the fixing points for the external power supply lines are designed as two-part contacts, with a portion, preferably a small portion, of each fixed contact actually soldered with a hard solder, and a second portion, which is not subjected to the soldering process, added later. This has the advantage of not having a weight disadvantage compared to a conventional one-part contact, preferably with no or only a slight increase in contact resistance due to the same material, and nevertheless achieving an increase in mechanical strength compared to a one-part fixed contact. By the above-mentioned measures, the second portion can be reliably fixed to the soldered first portion. As a result, the fixed contacts and the switching device described herein can be manufactured inexpensively with little or no increase in process costs and are capable of higher mechanical loads compared to one-part fixed contacts.

[0042] Further advantages, advantageous embodiments and developments will become apparent from the examples described below in conjunction with the drawings. [Brief explanation 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] 2 is a schematic diagram of a fixed contact of a switching device. FIG. [Figure 2B] 2 is a schematic diagram of a fixed contact of a switching device. FIG. [Figure 2C] 2 is a schematic diagram of a fixed contact of a switching device. FIG. [Figure 2D] 2 is a schematic diagram of a fixed contact of a switching device. FIG. [Figure 2E] 2 is a schematic diagram of a fixed contact of a switching device. FIG. [Figure 3A] 5A and 5B are schematic diagrams of a method for attaching a fixed contact to a switching chamber cover of a switching device according to a further embodiment; [Figure 3B]5A and 5B are schematic diagrams of a method for attaching a fixed contact to a switching chamber cover of a switching device according to a further embodiment; [Figure 4] 5 is a schematic diagram of a fixed contact of a switching device according to a further embodiment; [Figure 5] 5 is a schematic diagram of a fixed contact of a switching device according to a further embodiment; [Figure 6] 5 is a schematic diagram of a fixed contact of a switching device according to a further embodiment; [Figure 7A] 5 is a schematic diagram of a fixed contact of a switching device according to a further embodiment; [Figure 7B] 5 is a schematic diagram of a fixed contact of a switching device according to a further embodiment; [Figure 8A] 5 is a schematic diagram of a fixed contact of a switching device according to a further embodiment; [Figure 8B] 5 is a schematic diagram of a fixed contact of a switching device according to a further embodiment; DETAILED DESCRIPTION OF THE INVENTION

[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 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.

[0045] 1A and 1B show an example of a switching device 100, 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 FIG. 1A, a three-dimensional cross-sectional view is shown along a vertical cutting plane. In FIG. 1B, an enlarged view of section BB shown in FIG. 1A is shown. The illustrated geometries 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 serves primarily as contact protection for the components arranged therein and comprises or consists of a plastic, such as PBT or glass-fiber-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, are also 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 copper with at least one other metal, such as Wo, Ni, and / or Cr.

[0047] In FIG. 1A , the switching device 100 is shown in a switched-off state, in which the contact bridge 4 is separated from the fixed contact 2, thereby electrically disconnecting the contacts 2 and 4. To switch the switching device 100 into a switched-on state, the illustrated contact bridge 4 must be moved upward toward the fixed contact 2 until it mechanically contacts the fixed contact 2. In the illustrated embodiment, the switching device 100 comprises a magnetic drive with a movable magnet armature 5, which essentially performs the switching operation. The magnet armature 5 has a magnetic core 6, which may for example comprise or consist of a ferromagnetic material. The magnet armature 5 further comprises a shaft 7, which is guided 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 magnet armature 5 comprises the contact bridge 4. The shaft 7 may preferably comprise or be made of special steel.

[0048] In order 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 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, which exerts a force on the contact bridge 4 in the direction of the fixed contact 2.

[0049] The magnetic core 6 is surrounded by a coil 8. A current in the coil 8, which can be externally connected via a control circuit, causes an axial movement of the magnetic core 6, and thus of 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 5 moves upwards for this purpose. In this way, the magnetic 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 or switched-on state. In the active state, the switching contacts are electrically connected to each other.

[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 form part of the magnetic circuit. The yoke 9 has an opening through which the shaft 7 is guided. Furthermore, for example, a guide sleeve (not shown) 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. Thus, in the illustrated example, the magnet armature 5 moves downward again. The switching device 100 is then again in an idle state with the contacts open.

[0051] For example, when the switching contacts are opened, at least one arc may occur, potentially damaging the contact surfaces of the switching contacts. This can lead to a risk that the switching contacts will become "stuck" together and no longer separate due to welding caused by the arc. The switching device 100 is then still switched on, even though the current in the 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 extinguishing of any arcs that may occur, the switching contacts can be placed in a gas atmosphere, so that the switching device 100 can be designed as a gas-filled relay or contactor. In particular, the switching contacts within the switching chamber 11, formed by the switching chamber cover 12 and the switching chamber bottom 13, are located within a hermetically sealed region 14, which the switching chamber 11 can be part of. The hermetic region 14 completely surrounds the magnet armature 5 and the switching contacts, except for the portion of the fixed contact 2 that is provided for external connection. The gas-tight region 14, and thus the interior space 15 of the switching chamber 11, is also filled with gas. The gas-tight 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 gas-tight region 14 through the gas-filling nozzle 17 during the manufacture of the switching device 100 is preferably a hydrogen-containing gas, such as a gas 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.

[0052] The switching chamber cover 12 and the switching chamber bottom 13 can 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 can be made at least in part from ceramics, in particular from the structure (CHO) n Such plastics may be characterized by a relatively low carbon content and very little tendency to form graphite. In particular, (CHO) n In this case, the carbon and oxygen contents are identical, which can lead to the generation of mainly gaseous CO and H2 during thermally induced, especially arc-induced, decomposition. The 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 plastic, as described above.

[0053] The fixed contact 2 is arranged in an opening 121 in 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, a 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 an attachment area 122 of the switching chamber cover 12 that 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 having the fixing part 20 and the connecting part 21 has an edge area 203 with a fixing edge 205, and a hard solder (not shown) is arranged between the edge area 203 and the attachment area 122. For example, a silver- and / or copper-based solder can be used as the hard solder, particularly preferably a silver-copper alloy such as Ag72Cu28. The method steps of the method for attaching the fixed contact 2 to the switching chamber cover 12 are explained in relation to Figures 3A and 3B.

[0054] To connect the fixed contact 2 to an external power supply (not shown) of the load circuit, the fixed contact 2 has a connecting element 211 formed as a so-called stud bolt, which protrudes through the opening 101 of the housing 1 as shown in FIGS. 1A and 1B and to which an external power supply, such as a supply rail, a so-called bus bar, or a cable lug, is attached to the outside of the housing 1. The connecting element 211 can have a thread, as will be explained in connection with the following figures, so that the external power supply can be fixed to the connecting element 211 and thus to the fixed contact 2 and pressed against the support element 213, for example, using a nut. To achieve the lowest possible electrical contact resistance between the external power supply and the fixed contact 2 and to ensure a permanent mechanical connection even in the event of shear and lever forces that may occur during operation, a sufficiently large tightening torque for screwing the nut onto the connecting element 211 is required. Therefore, the connecting element 211 in particular must have sufficient mechanical strength. In other words, the material of the connecting 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 two parts in the illustrated switching device 100. Further features and embodiments of the fixed contact 2 are explained in connection with the following figures.

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

[0057] 1A and 1B, the fixed contact 2 has two parts formed by the fixed part 20 and the connecting part 21, which, when joined, essentially form at least one fixed contact 2 and are permanently joined in the switching device. Particularly preferably, the connecting part 21 and the fixed part 20 are joined to each other at least by engagement and / or 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 joined to each other by bonding through intermolecular forces, as will be explained in relation to FIGS. 4 to 8B.

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

[0059] The fixing 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 all the way through the fixing part 20. In particular, the fixing part 20 can be formed in the shape of a cup with a bottom region 201 and a wall region 202 connected thereto. The bottom region 201 is provided with a contact surface 28 on its side opposite the connecting part 21.

[0060] The connecting part 21 has a connecting 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 connecting element 211 extends from an upper surface 214 of a support element 213 in a direction away from the fixing part 20. The support element 213 is particularly preferably formed in the form of a disk, particularly preferably a circular disk, from the center of which the connecting element projects, as can be seen, for example, in Figure 2A.

[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 when viewed from the support element 213.

[0062] The coupling element 216 protrudes into and is located in the recess 200 of the fixing 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 fixing part 20 has a matching internal thread 207 in the wall region 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 direction of rotation and thus may both be right-hand threads, for example.

[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 connection and 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 have in particular an edge region 203 with an upper side 204 on which the underside 215 of the support element 211 rests, so that the 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 may, for example, both be ring-shaped 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 may each be partially arranged within an opening in 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, may be arranged inside the opening in the housing.

[0067] 1A and 1B, the edge region 203 has a fixed edge 205 facing the switching chamber, which is bonded to the switching chamber by intermolecular forces. The fixed edge 205 can be separated from the wall region 202, for example, by a circumferential 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 scope of the production of a switching device.

[0068] As shown in FIG. 3A , the fixing parts 20 are inserted into the openings 121 of the switching chamber cover 12 so that the fixing edges 205 are positioned on the mounting areas 122. The mounting areas 122 can be formed, for example, by a raised ring structure in the edge area of ​​the opening 121. A hard solder 120, such as a silver- and / or copper-based solder, particularly preferably a silver-copper alloy such as Ag72Cu28, is applied between the mounting areas 122 and the fixing edges 205. The switching chamber cover 12, together with the fixing parts 20 of all the fixed contacts 2 arranged in this manner, is heated, for example, in an oven, so that a gas-tight connection is established between the switching chamber cover 12 and the fixing parts 20 via the melted and re-solidified hard solder 120. Subsequently, as shown in FIG. 3B , a connecting part 21 can be screwed onto each fixing part 20.

[0069] Particularly preferably, the connecting part 21 and the fixed part 20 are made of the same material, for example, including 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 connecting part 21 due to the hard soldering process. Due to the typically high temperatures, for example, above 800°C, during hard soldering, the material of the fixed part 20 may become softer after hard soldering due to solid-state physical processes. In contrast, the connecting part 21 does not undergo a hard soldering process and is screwed in after hard soldering, so it may maintain its original hardness.

[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 in order to be fastened later. 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 that may later act on the connecting element 211 from damaging the internal thread 207 of the fixed part 20 through a lever action. It has been shown that even with a relatively small tightening torque of about 4 Nm, 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 clarity, only the described components are indicated with reference numerals 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 external threads 217 of the coupling element 216 of the connecting portion 21 and the internal threads 207 of the recess 200 of the fixing portion 20, as shown by the dashed area. The bonding material 23 may include, or may be, an adhesive, for example, including or consisting of an acrylate, such as a methacrylate or a cyanoacrylate. The adhesive may harden after the connecting portion 21 is attached to the fixing portion 20 and prevent the connecting portion 21 from unintentionally loosening.

[0073] As shown in FIG. 5 , the bonding material 24 can be placed in a recess 200 below the bonding element 216 of the connecting element 21. For this purpose, 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 connecting 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 placed. The bonding material 24 can comprise or consist of an adhesive, such as the adhesive described above, or particularly preferably a soft solder. The soft solder can be placed, for example, in the form of a solder pill in the recess 200 of the fastening part 20 already secured to the switching chamber. After the screwing of the connecting part 21, the soft solder can be melted, for example, by heating in an oven; the temperatures required for this are significantly lower than in hard soldering processes and do not result in softening of the connecting part 21. The soft solder, as described above in the general section, is preferably lead-free, e.g., 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 residue remains 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 may be arranged between the lower surface 215 of the support element 213 of the connecting part 21 and the upper surface 204 of the edge region 203 of the fixing part 20. For example, the bonding material 25 may comprise or consist of an adhesive or, particularly preferably, a soft solder as described above.

[0075] 5 and 6, before the connection part 21 is screwed into the fixed part 20, a bonding material 24, 25, preferably in the form of a soft solder, can be applied near the thread in the recess 200 or on the outer edge, i.e., the support surface formed by the upper surface 204 of the edge region 203. For example, after the connection part 21 is attached, the flux-containing solder can be brought to its melting temperature, preferably below 300°C, which results in melting and subsequently a strong bond. The low melting point of the soft solder prevents a decrease in the hardness of the connection part 21, which typically occurs only at temperatures above 500°C for copper and copper alloys. 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 at 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 connecting part 21 can have a surface structure 209, 219, for example a knurled and / or roughened surface, which can be produced, for example, by sandblasting. The surface structure 209, 219 can particularly preferably be provided in association with the 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 FIGS. 8A and 8B , the support elements 213 of the connecting part 21 can be welded to the edge region 203 of the fixing part 20. After screwing the connecting part 21 to the fastening part 20, the contact edges are welded around the entire edge or partially. In particular, the support elements 213 can be connected to the edge region 203 outside the contact area formed by the lower surface 215 of the support elements 213 and the upper surface 204 of the edge region 203 by a weld seam 26, indicated by the dashed area in FIG. 8A , which can particularly preferably be completely circumferential. The weld seam 26 can particularly preferably be formed by laser welding. Welding has the advantage of short process times. Furthermore, a high level of safety can be achieved against unintentional detachment of the connecting part 21 from the fixing 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 Figure 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 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.

[0080] 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]

[0081] 1. Housing 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 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 seam 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 fixed portion is fixed to the switching chamber, A switching device (100) wherein the connecting portion (21) and the fixing portion (20) are made of the same material, and the fixing portion (20) has a lower hardness than the connecting portion (21).

2. The switching device according to claim 1, wherein the connecting portion protrudes into a recess (200) in the fixing portion.

3. The switching device according to claim 2 , wherein the fixing portion is formed in a cup shape, and the recess is formed as a blind hole.

4. A switching device as described in claim 2 or 3, wherein a bonding material (24) including soft solder is arranged within the recess below the connection portion.

5. A switching device as described in Claim 4, wherein the recess (200) has a cavity below the connection portion, and the bonding material (24) is arranged in the cavity.

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 the housing (1) of the switching device and formed by a stud bolt.

7. 7. The switching device of claim 6, wherein the connection portion has a support element (213) and the connection portion extends 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 fixing part at the 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, wherein the switching device (100) has 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) in 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), the surface structure being knurled and / or roughened.

12. 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.

13. 10. The switching device of claim 9, wherein the support element is welded to the edge region.

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

15. The switching device according to any one of claims 1 to 3, wherein the connecting part projects into a recess of the fixing part with a coupling element (216) and is screwed into the recess with the coupling element.

16. 16. The switching device according to claim 15, wherein the coupling element has an external thread (217) and the recess of the fastening part has an internal thread (207).

17. The switching device according to claim 16 , wherein the external thread and / or the internal thread have an interference fit before the connecting part is screwed onto the fixing part.

18. 17. The switching device of claim 16, wherein a bonding material (23) comprising an adhesive is disposed between the external thread and the internal thread.

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