Switching device

Abstract

The invention relates to a switching device (100), comprising at least one fixed contact (2), which protrudes into a switching box (11), said at least one fixed contact having a fastening part (20), which is fastened to the switching box, and a coupling part (21), which protrudes into a recess (200) of the fastening part.

Description

Technical Field

[0001] A switch device is described. Background Art

[0002] The switching device is particularly designed as an electromagnetically activated remote-controlled switch operable by a conductive current. The switching device can be activated via a control circuit and can switch a load circuit. In particular, the switching device can be designed as a relay or a contactor, in particular as a power contactor. Particularly preferably, the switching device can be designed as a gas-filled power contactor.

[0003] Possible applications for such switching devices, in particular power contactors, include, for example, disconnecting and isolating battery circuits in motor vehicles, such as electrically or partially electrically operated ones. These motor vehicles can be, for example, purely battery-powered vehicles (BEVs), hybrid electric vehicles (PHEVs) that can be charged via a socket or a charging station, and hybrid electric vehicles (HEVs). In this case, both the positive and negative contacts of the battery are usually disconnected by means of the power contactors. This disconnection occurs during normal operation, for example when the vehicle is stationary, and also in the event of disturbances such as accidents. The main task of the power contactors is to de-energize the vehicle and interrupt the current flow.

[0004] During operation, the contactor usually carries high currents. The high currents are usually transmitted via leads such as copper busbars (so-called busbars) or other leads, which are mounted on externally accessible contacts of the contactor, which may also be referred to as pole contacts or terminals. The copper busbars or other leads may have a diameter of 200 mm. 2 To ensure adequate, low-resistance electrical contact, the leads must be installed with a sufficiently high pull-in torque, which places high mechanical demands on the contact points of the contactor. Furthermore, shear and lever forces can occur at the contact points during installation and later operation. Therefore, the contact points should be made of a particularly hard yet highly conductive material.

[0005] Particularly efficient contactors have a switching housing made of ceramic material, into which the contact pieces are soldered using hard solder at temperatures exceeding 800°C. However, this process carries the risk that the material properties of the most readily conductive materials that can be used for the contact pieces change, becoming softer. Consequently, sufficient fastening of the leads is no longer possible without difficulty.

[0006] To circumvent this problem, for example, a material can be used that is still hard enough after the welding process to withstand the loads. However, this usually results in an expensive base material being used, since, for example, special copper alloys must be used. Furthermore, it is also known to integrate busbar elements into the contactor, which allow for additional, spatially shifted fastening points to be realized. However, this leads to disadvantages, such as high costs due to the additional components, a higher final weight of the contactor, and increased electrical contact resistance from fastening point to fastening point.

[0007] The publications JP 2005-038 706 A, JP H11-232 986 A, US 2008 / 0 122 562 A1, US 2016 / 0012 995 A1 and DE 10 2019 129 805 B3 describe switching devices. Summary of the Invention

[0008] At least one object of certain specific embodiments is to specify a switching device.

[0009] This object is achieved by the subject matter according to the independent patent claims. Advantageous embodiments and developments of the subject matter are characterized in the dependent claims and are also apparent from the following description and the drawings.

[0010] According to at least one embodiment, the switching device has at least one fixed contact piece. The at least one fixed contact piece can be provided and designed in particular for connecting electrical leads of a load circuit that is to be switched, ie closed, and switched, ie disconnected, by the switching device.

[0011] Furthermore, the switching device may include at least one movable contact. The movable contact may, in particular, include or be a contact bridge. In other words, the contact bridge may be the movable contact of the switching device or part of the movable contact of the switching device. The properties and features of the movable contact described below may also correspond to the properties and features of the contact bridge, and vice versa.

[0012] At least one fixed contact and at least one upper movable contact are provided and configured to connect and disconnect a load circuit connectable to the switching device. The movable contact, in particular a contact bridge, is movable in the switching device between a non-engaged state and an engaged state of the switching device. In the non-engaged state, the movable contact, in particular the contact bridge, is spaced apart from the at least one fixed contact and thus galvanically isolated, and in the engaged state, is in mechanical contact with the at least one fixed contact and thus galvanically connected to the at least one fixed contact. Hereinafter, the engaged state is also referred to as the switched-on state of the switching device, while the non-engaged state is referred to as the switched-off state of the switching device.

[0013] Particularly preferably, the switching device has at least two fixed contacts, which are arranged separately from one another in the switching device and can be electrically connected to one another or electrically disconnected from one another via the movable contact, in particular the contact bridge, in the manner described above, depending on the state of the movable contact, in particular the contact bridge. The contact bridge preferably has an upper side with at least one contact region and a lower side opposite the upper side. In the engaged state of the switching device, at least one contact region of the contact bridge is in mechanical contact with at least one fixed contact, in particular a contact region of at least one fixed contact. If the switching device has, for example, two fixed contacts, the contact bridge can accordingly have two contact regions. The features described below with respect to the fixed contacts can apply to a plurality of fixed contacts and particularly preferably to each fixed contact of the switching device.

[0014] In the following, the general term "contact element" may particularly refer to all fixed contacts and contact bridges. In particular, the contact element may comprise or consist of a metal, preferably copper or a copper alloy. Furthermore, at least for the contact region, a composite material in the form of a metallic matrix material (preferably made of or consisting of copper) and particles distributed therein (preferably made of or consisting of a ceramic material, such as, for example, aluminum oxide) may also be used.

[0015] According to another embodiment, the switching device comprises a housing in which a movable contact and at least one fixed contact or at least two fixed contacts are arranged. The movable contact can, in particular, be arranged completely in the housing. Arranging the fixed contact in the housing can, in particular, mean that at least a contact region of the fixed contact is arranged within the housing, which contact region, in the engaged state, is in mechanical contact with the movable contact. In order to connect the leads of the circuit to be switched by the switching device, the fixed contacts arranged in the housing can be electrically contacted from the outside, i.e., from outside the housing. For this purpose, the fixed contacts arranged in the housing can protrude from the housing in a portion and have a connection possibility for the electrical leads outside the housing.

[0016] According to another embodiment, the contacts are arranged in the atmosphere of the housing. This can mean, in particular, that the movable contact is completely arranged in the atmosphere of the housing, and furthermore, that at least parts of the one or more fixed contacts, for example, one or more contact regions of one or more fixed contacts, are arranged in the atmosphere of the housing. Accordingly, the switching device can particularly preferably be a gas-filled switching device, such as, for example, a gas-filled contactor.

[0017] According to another embodiment, the switch device has a switch box. The switch box can be arranged in particular within a housing. In particular, the switch box has an interior space. The contacts, meaning the movable contacts, are arranged completely within the interior space of the switch box, as well as a portion of at least one fixed contact. Thus, the at least one fixed contact extends into the switch box. In particular, the at least one fixed contact extends through an opening into the interior space of the switch box. In other words, the at least one fixed contact is located partially within the switch box and partially outside the switch box. For example, the switch box can have a switch box bottom. The switch box can also have a switch box cover, which, together with the switch box bottom, can enclose the interior space. At least in the region where the at least one fixed contact extends into the switch box, the switch box is made of a ceramic material, for example, made of or made of aluminum oxide. For example, the at least one fixed contact can protrude through an opening in the switch box cover. In this case, the switch box cover is preferably made of a ceramic material.

[0018] A gas, i.e., at least a portion of the aforementioned atmosphere, may be located in the switch cabinet. This gas may preferably have a H2 content of at least 20% and preferably at least 50%. In addition to hydrogen, the gas may contain an inert gas, particularly preferably N2, and / or one or more noble gases.

[0019] According to another embodiment, the movable contact can be moved in the switching device by means of a shaft. In particular, the movable contact can be movable, for example, by means of a drive device having a shaft, wherein the drive device can be constructed in the form of a magnetic drive device having an armature or in the form of an electric motor drive device. The shaft can be connected to the movable contact at one end so that the movable contact can be moved by means of the shaft, that is, when the shaft moves, the movable contact is also moved by the shaft. The shaft can especially extend into the interior space of the switch box through an opening in the switch box. In the case of a magnetic drive device, the armature can be movable through a magnetic circuit in order to realize the switching process described previously. To this end, the magnetic circuit can have a yoke, which has an opening, through which the shaft of the armature protrudes. The shaft can preferably have stainless steel or be made thereof. Preferably, the yoke can have pure iron or a low-doped iron alloy or be made of pure iron or a low-doped iron alloy.

[0020] According to another embodiment, at least one fixed contact has two parts that, when joined, essentially form the at least one fixed contact. The two parts are permanently joined in the switching device. Particularly preferably, the two parts are permanent and, therefore, joined such that they cannot be separated from one another under normal operating conditions. Furthermore, the at least one fixed contact may include one or more connecting materials that improve the permanent connection between the two parts.

[0021] In particular, at least one fixed contact element comprises a fastening portion and a coupling portion as two parts, which together essentially form the at least one fixed contact element, i.e., for example, apart from at least one connecting material. Particularly preferably, the coupling portion and the fastening portion are connected to each other at least in a form-fitting and / or force-fitting manner, for example, by a clip connection or, particularly preferably, by a screw connection. Furthermore, the coupling portion and the fastening portion may also be connected to each other in a material-fitting manner.

[0022] The fastening portion is configured and arranged to be fastened to the switch box, such that the at least one fixed contact is fastened to the switch box via the fastening portion. In particular, the fastening portion can be materially connected to the switch box. The coupling portion is configured and arranged to be connected to an external electrical lead, such that the at least one fixed contact can be connected to the external electrical lead via the coupling portion.

[0023] According to another embodiment, the fastening portion has a recess and the coupling portion extends into the recess of the fastening portion. The recess can particularly preferably be configured as a blind hole so that the coupling portion does not protrude through the fastening portion. In particular, the fastening portion can be configured in a cup-shaped manner. The fastening portion can have a contact surface at the bottom area on the side opposite to the coupling portion, with which the fastening portion and therefore the at least one fixed contact are in mechanical contact with the movable contact in the engaged state of the switching device. The contact surface is thus arranged in the switch box. Therefore, the above-mentioned internal mechanical contact with the movable contact is preferably carried out via the fastening portion, while the external mechanical contact with the external lead is carried out via the coupling portion.

[0024] According to another embodiment, the connection portion is accessible from outside the switchgear. In particular, the connection portion may include a connection element, which is arranged outside the housing of the switchgear. The connection element may, for example, be formed by a support bolt. The support bolt particularly preferably has an external thread. Alternatively, the connection element may also include or be a threaded hole in the connection portion.

[0025] Furthermore, the coupling portion can have a support element, from which the coupling element extends. In particular, the coupling element can extend in a direction facing away from the fastening portion, as viewed from the support element. To this end, the support element can particularly preferably have an upper side facing away from the box, from which the coupling element protrudes.

[0026] The supporting element can, for example, be disc-shaped, particularly preferably in the form of a circular disc, with a coupling element, for example in the form of a support bolt, protruding centrally from the circular disc. The coupling element can be provided for positioning and arranging as well as for fastening the external electrical lead. If the coupling element has an external thread, a clamping nut can be screwed onto the coupling element, for example. The upper side of the supporting element can constitute a supporting surface for the external electrical lead, against which the external electrical lead is pressed in the tightened state, i.e., for example, when the clamping nut is actuated, in order to achieve the lowest possible electrical contact resistance between the at least one fixed contact and the first electrical lead. Thus, the external electrical lead can, for example, have a hole through which the coupling element protrudes, and can also be clamped between the supporting element and the clamping nut screwed onto the coupling element.

[0027] According to another embodiment, the coupling portion includes a connecting element. The connecting element is preferably arranged on the side of the support element opposite the coupling element. The connecting element can, for example, be formed by a support bolt. In particular, the connecting element can extend in a direction facing the fastening portion when viewed from the support element. To this end, the support element can particularly preferably have an underside facing the switch box, from which the connecting element protrudes.

[0028] In particular, the connecting element can extend into a recess in the fastening part and can particularly preferably be arranged in the recess. The coupling part can particularly preferably be screwed into the recess using the connecting element. To this end, the connecting element can have an external thread, and the recess in the fastening part can have an internal thread. Particularly preferably, the coupling element and the connecting element can each have external threads with the same thread size.

[0029] According to another embodiment, before the coupling part is screwed into the fastening part, the external thread of the connecting element and / or the internal thread of the recess have an interference fit. In other words, the internal thread of the recess is given a smaller tolerance than the external thread of the connecting element. The thread preferably complies with the guidelines DIN 13-1 to DIN 13-52, particularly preferably DIN 13-51 (transition tolerance zone for tight fit). For example, there may be a fit "M8-5H / 4h" (transition fit). The guidelines according to DIN 13 generally relate to fine threads, such as threads of types M6, M8, etc. Other thread types are also included, such as non-metric thread types, for example according to ASME Bl.1 and special threads, for example according to DIN 7756 and valve threads. By screwing the connecting element into the recess, a more secure screw connection can be achieved due to the interference, by which the coupling part can be prevented from being accidentally screwed out of the fastening part.

[0030] According to another embodiment, the connecting material is arranged between the external thread of the connecting element and the internal thread of the recess. The connecting material can include an adhesive or can be an adhesive, for example made of or with an acrylate, such as methacrylate or cyanoacrylate.

[0031] According to another embodiment, the connecting material is arranged in a recess below the connecting element. To this end, the recess can particularly preferably have a depth greater than the height of the connecting element measured from the underside of the support element, so that when the connecting part is fully screwed into the fastening part, a cavity remains below the connecting element, in which the connecting material can be arranged. The connecting material can include or be made of an adhesive, such as the adhesive described above, or soft solder. Here and below, solder preferably having a melting point of less than or equal to 400°C is referred to as soft solder. The soft solder can be arranged, for example, in the form of solder pellets, in the recess of the fastening part that has been fastened to the switch box. After the connecting part is screwed in, the soft solder can be melted by heating, for example, in a furnace. The soft solder can be flux-free. Alternatively, a flux can be provided to the soft solder. For example, the flux can improve the wetting properties of the soft solder. The soft solder can preferably be lead-free. For example, the soft solder can contain or be made of one or more materials selected from bismuth (Bi), tin (Sn), and antimony (Sb). For example, the mass fractions for bismuth and tin can each be greater than or equal to 25% and less than or equal to 35%, and particularly preferably greater than or equal to 27% and less than or equal to 31%. For antimony, the mass fractions can be greater than or equal to 50% and less than or equal to 70%, and particularly preferably greater than or equal to 38% and less than or equal to 46%. Furthermore, the soft solder can, for example, contain or be made of one or more materials selected from tin (Sn), silver (Ag), and copper (Cu). For example, the mass fraction for tin can be greater than or equal to 50%, and particularly preferably greater than or equal to 85%. The mass fraction for silver can be less than 15%, and preferably less than 5%. The mass fraction for copper can be less than 5%, and preferably less than 1%. For example, the soft solder can be Sn96.5Ag3.0Cu0.5.

[0032] According to another embodiment, the support element rests with its underside on the fastening part. The fastening part can have an edge region with an upper side on which the underside of the support element rests. The edge region can particularly preferably be configured to surround the recess in the fastening part.

[0033] According to another embodiment, the connecting material is arranged between the bottom side of the carrier element and the top side of the edge region.For example, the connecting material can include or be a soft solder, such as the soft solder described above.

[0034] According to another embodiment, the upper side of the edge region of the fastening part and / or the lower side of the supporting element of the coupling part has a surface structure, for example, knurling and / or roughening. The surface structure can particularly preferably be provided in conjunction with the connecting material between the lower side of the supporting element and the upper side of the edge region.

[0035] According to another embodiment, the support element is welded to the edge region. In particular, the support element can be connected to the edge region by means of a weld seam on the outer side of a contact region formed by the bottom side of the support element and the top side of the edge region, wherein the weld seam can particularly preferably be completely circumferential.

[0036] The fastening of the coupling part at the fastening part can be improved by one or more of the aforementioned connecting materials and / or surface structures and / or welding. The risk of the coupling part accidentally coming loose from the fastening part can thereby be reduced or even prevented.

[0037] The support element and the edge region can particularly preferably have the same outer diameter. The upper side of the edge region and the lower side of the support element can, for example, both be annular and arranged to overlap one another. Furthermore, the support element and the edge region can each be partially arranged within an opening in the housing of the switch device. In particular, the contact area between the support element and the edge region, i.e., the upper side of the edge region and the lower side of the support element, can be arranged within the housing opening.

[0038] According to another embodiment, the edge region has a fastening edge facing the switch box, which is connected to the switch box in a material-fitting manner. In other words, the fastening edge is arranged opposite the upper side. In particular, the fastening edge can be connected to the switch box by means of hard solder, thereby fastening the at least one fixed contact to the switch box. The switch box can have a corresponding edge region surrounding the opening, through which at least one fixed contact, i.e., in particular the fastening part, extends into the switch box. The edge region can, for example, be formed by a convex ring structure, and the fastening edge is fastened to the edge region by means of hard solder. Here and in the following, solder with a melting point greater than or equal to 600°C is referred to as hard solder. For example, a solder based on silver and / or copper can be used as hard solder, particularly preferably a silver-copper alloy such as Ag72Cu28.

[0039] According to another embodiment, the connecting part and the fastening part are made of the same material. In particular, the connecting part and the fastening part can each comprise or be made of the materials generally mentioned above for the contacts, i.e., for example, metal, preferably copper or a copper alloy. In the installed state, i.e., when the at least one fixed contact is fastened to the switch housing, the fastening part can have a lower hardness than the connecting part. This can be achieved by soldering the fastening part to the switch housing using brazing material. Due to the typically high temperatures during brazing, such as 800°C or higher, the material of the fastening part may be softer after brazing due to solid-state physical processes. However, since the connecting part is not subjected to the brazing process but is screwed in after brazing, it retains its original hardness.

[0040] In the switching device described here, one or more fixed contacts, which form the fastening points for the external electrical leads, are designed in two parts, with only one part, preferably a small portion, of each fixed contact being actually soldered in by means of brazing, while the second part, which does not undergo the welding process, is added later. This has the advantages that there is no weight disadvantage compared to conventional one-piece contacts, the contact resistance is not increased or only slightly increased due to the preferably identical materials, and that increased mechanical strength is achieved compared to one-piece fixed contacts. The measures described above allow the second part to be securely fastened to the welded-in first part. As a result, the fixed contacts and the switching device described here can be advantageously manufactured with little or no increased process effort, and higher mechanical loads are possible compared to one-piece fixed contacts. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Further advantages, advantageous embodiments and developments result from the exemplary embodiments described below in conjunction with the figures.

[0042] Figure 1A and 1B A schematic diagram showing an embodiment of a switching device,

[0043] Figures 2A to 2E A schematic diagram showing the fixed contacts of a switching device, and

[0044] Figure 3A and 3B A schematic diagram showing a method for mounting a fixed contact on a switch box cover of a switch device according to another embodiment,

[0045] Figures 4 to 8B Schematic diagrams showing fixed contacts of a switch device according to other embodiments.

[0046] In the embodiments and figures, identical, similar, or identically functioning elements may be provided with the same reference numerals. The illustrated elements and their dimensional relationships should not be considered to be drawn to scale; rather, individual elements such as layers, components, devices, and regions may be shown exaggerated for better representation and / or for a better understanding. DETAILED DESCRIPTION

[0047] exist Figure 1A and 1B An embodiment of a switching device 100 is shown in FIG. 1 , which can be used, for example, for switching high currents and / or high voltages and can be a relay or a contactor, in particular a power contactor. Figure 1A A three-dimensional cross-sectional view with a vertical cross-sectional plane is shown in FIG. Figure 1B In the figure, the enlarged Figure 1A The fragment BB is shown in FIG. The shown geometries are to be understood only as exemplary and non-restrictive and can also be configured alternatively.

[0048] The switching device 100 has contact members 2 and 4 in a housing 1, which are also referred to as switching contacts below. The housing 1 serves in particular as a contact protection device for components arranged in the interior and comprises or is made of a plastic, such as PBT or glass-fiber-filled PBT. In the example shown, the switching device 100 has two fixed contacts 2 and a movable contact in the form of a contact bridge 4 placed on an insulating body 3 as contact members. The contact bridge 4 is constructed as a contact plate. The fixed contact 2 and the contact bridge 4 together constitute the switching contact. As an alternative to 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 contact 2 and / or the contact bridge 4 can, for example, be made of or be made of Cu, a Cu alloy, or a mixture of, for example, copper and at least one other metal, such as Wo, Ni, and / or Cr.

[0049] exist Figure 1A In the figure, the switching device 100 is shown in the off state, with the contact bridge 4 spaced apart from the fixed contact 2, so that the contacts 2 and 4 are electrically isolated from each other. To switch the switching device 100 to the on state, in the illustration shown, the contact bridge 4 must be moved upward in the direction of the fixed contact 2 until it comes into mechanical contact with the fixed contact 2. In the illustrated embodiment, the switching device 100 has a magnetic drive with a movable armature 5, which essentially performs the switching movement. The armature 5 has a magnetic core 6, for example, made of or composed of a ferromagnetic material. The armature 5 also has a shaft 7, which is guided through the magnetic core 6 and is securely connected to the magnetic core 6 at one shaft end. At the other shaft end, opposite the magnetic core 6, the armature 5 has the contact bridge 4. The shaft 7 can preferably be made of or composed of stainless steel.

[0050] To electrically insulate the contact bridge 4 from the shaft 7 , an insulator 3 , which can also be referred to as a bridge insulator, is arranged between the contact bridge 4 and the shaft 7 . To compensate for any height differences and to ensure adequate mechanical contact between the stationary contact 2 and the contact bridge 4 , a contact spring 34 is arranged below the contact bridge 4 . The contact spring 34 is supported on the insulator 3 and exerts a force on the contact bridge 4 in the direction of the stationary contact 2 .

[0051] The magnetic core 6 is surrounded by a coil 8. The flow of current in the coil 8, which can be introduced externally via a control circuit, causes the magnetic core 6 and, therefore, the entire armature 5, to move axially until the contact bridge 4 contacts the fixed contact 2. In the illustrated diagram, the armature 5 moves upward for this purpose. Thus, the armature 5 moves from a first position, or rest position, corresponding to a disengaged, non-engaged, and thus switched-off state, to a second position, or engaged, and thus switched-on state. In the activated state, the switch contacts are galvanically connected to one another.

[0052] To guide the shaft 7 and thus the armature 5, the switching device 100 has a yoke 9, which can include or be made of pure iron or a low-doped iron alloy and forms part of the magnetic circuit. The yoke 9 has an opening in which the shaft 7 is guided. Furthermore, a guide sleeve (not shown), for example, can be located in the opening of the yoke 9. If the current flow in the coil 8 is interrupted, the armature 5 is moved back to the first position by one or more springs 10. In the illustrated diagram, the armature 5 is thus moved downward again. The switching device 100 is then once again in the idle state with the contacts open.

[0053] For example, when opening the switch contacts, at least one arc may be generated, which could damage the contact surfaces of the switch contacts. This creates the risk that the switch contacts will remain "adhered" to one another due to the arc-induced welding and no longer separate. Even if the current in coil 8 is interrupted and the load circuit must be disconnected, the switching device 100 remains in the switched-on state. To prevent the formation of such arcs or at least to support the extinguishing of any arcs that occur, the switch contacts can be arranged in an atmosphere, allowing the switching device 100 to be configured as a gas-filled relay or contactor. In particular, the switch contacts are arranged within a switch housing 11, for example, consisting of a switch housing cover 12 and a switch housing bottom 13, in a gas-tight area 14 formed by a sealed enclosure. The switch housing 11 can be part of the gas-tight area 14. The gas-tight area 14 completely surrounds the armature 5 and the switch contacts, except for the portion of the fixed contact 2 provided for external connection. The gas-tight area 14, and therefore also the interior space 15 of the switch housing 11, is filled with gas. The gas-tight area 14 essentially consists of the switch housing 11, the yoke 9, and parts of the additional wall. The gas that can be introduced into the gas-tight area 14 via the gas filling connection 17 during the manufacture of the switchgear 100 is particularly preferably hydrogen-containing, for example, 20% or more H₂ in an inert gas, or even 100% H₂, since hydrogen-containing gases can promote arc extinguishing. Furthermore, so-called quenching magnets, i.e., permanent magnets 16, can be present inside or outside the switch housing 11. These quenching magnets can extend the arc gap and thus improve arc extinguishing.

[0054] The switch box cover 12 and the switch box bottom 13 can be made of, for example, a ceramic material such as a metal oxide, for example Al2O3. Furthermore, plastics with sufficiently high thermal stability, such as PEEK, PE, and / or glass-fiber-filled PBT, are also suitable for the switch box bottom 13. Alternatively or additionally, the switch box 11 can also at least partially comprise POM, in particular with a structure (CH2O). n Such plastics can be characterized by a relatively low carbon content and a very low tendency to form graphite. n With the same carbon and oxygen content, gaseous CO and H2 can primarily form during thermal, and especially arc-induced, decomposition. The added hydrogen can enhance arc extinguishing. Particularly preferably, as previously described, the switchgear housing cover 12 is made of a ceramic material, and the switchgear housing base 13 is made of a ceramic material or plastic.

[0055] The fixed contact 2 is arranged in the opening 121 of the switch box cover 12 and protrudes through the opening 121 into the inner space 15 of the switch box 11, so that in particular the contact surface 208 of the fixed contact 2 is arranged in the inner space 15 of the switch box 11. The fixed contact 2 is permanently and in particular airtightly mounted in a material-fitting manner at the mounting areas 122 of the switch box cover 12 respectively surrounding the opening 121. The fixed contact 2 is particularly preferably mounted at the switch box 11 by brazing. To this end, the fixed contact 2 having a fastening portion 20 and a connecting portion 21 has an edge area 203 with a fastening edge 205, and a brazing material (not shown) is arranged between the edge area 203 and the mounting area 122. For example, a solder based on silver and / or copper can be used as the brazing material, particularly preferably a silver-copper alloy such as Ag72Cu28. In combination Figure 3A and 3B The method steps of a method for mounting the stationary contact piece 2 on the switch box cover 12 are described.

[0056] In order to connect the fixed contact 2 to an external electrical lead (not shown) of a load circuit, as in Figure 1A and 1BAs shown in FIG, the fixed contact protrudes through an opening 101 in the housing 1 and has a coupling element 211 outside the housing 1. This coupling element is configured, for example, as a so-called support bolt, to which an external lead, such as a lead busbar, a so-called busbar, or a cable lug, is attached. As explained in conjunction with the following figure, the coupling element 211 can have a thread, so that the external lead can be secured to the coupling element 211, and thus to the fixed contact 2, for example, by means of a screw nut, and can be pressed against a support element 213. To achieve the lowest possible electrical contact resistance between the external lead and the fixed contact 2 and to ensure a durable mechanical connection even under shear and lever forces that may occur during operation, a sufficiently high pull-in torque is required to screw the screw nut onto the coupling element 211. Therefore, the coupling element 211 must have sufficient mechanical strength. In other words, the material of the coupling element 211 must be sufficiently hard. However, as mentioned at the outset, the brazing process used to secure the fixed contact in conventional fixed contacts results in material changes and, in particular, softening.

[0057] In the case of the switching device 100 shown, the stationary contact piece 2 is therefore constructed in two parts. Further features and embodiments of the stationary contact piece 2 are explained in conjunction with the following figures.

[0058] exist Figures 2A to 2E Shown in accordance with Figure 1A and 1B In other words, the fixed contact 2 of the switch device 100 can be as shown in FIG. Figures 2A to 2E The fixed contact 2 is constructed as described in the previous section. Figure 2A and 2B 3D top view and 3D cross-sectional view of the fixed contact 2 are shown in FIG. Figures 2C to 2E Various other cross-sectional views of the stationary contact 2 or parts thereof are shown. The following description also relates to Figures 2A to 2E .

[0059] If combined Figure 1A and 1B As described, the fixed contact 2 has two parts consisting of a fastening part 20 and a connecting part 21, which together essentially form at least one fixed contact 2 and are permanently integrated into the switch device. Particularly preferably, the connecting part 21 and the fastening part 20 are connected to each other at least in a form-fitting and / or force-fitting manner, for example, by a clip connection or particularly preferably by a screw connection. In addition, the connecting part 21 and the fastening part 20 can also be connected to each other in a material-fitting manner, such as in combination. Figures 4 to 8B described.

[0060] The fastening portion 20 is provided and configured for this purpose as a combination Figure 1A and 1B As described, the fixed contact 2 is fastened to the switch box by means of brazing, so that the fixed contact 2 is fastened to the switch box by means of the fastening portion 20. Figure 1A and 1B As described, the coupling portion 21 is provided and configured to be connected to an external electrical lead, so that the fixed contact 2 can be connected to the external electrical lead by means of the coupling portion 21 .

[0061] The fastening portion 20 has a recess 200, and the coupling portion 21 projects into the recess 200 of the fastening portion 20. The recess 200 is configured as a blind hole so that the coupling portion 21 does not protrude through the fastening portion 20. In particular, the fastening portion 20 can be configured in a cup-shaped manner with a base region 201 and an adjoining wall region 202. The contact surface 208 is arranged on the side opposite the coupling portion 21 at the base region 201.

[0062] The coupling portion 21 has a coupling element 211 configured as a support bolt, such as Figure 1A and 1B As shown in , the coupling element 211 is arranged outside the housing of the switching device and has an external thread 212. The coupling element 211 extends from the upper side 214 of the support element 213 in the direction away from the fastening part 20. Figure 2A As can be seen in FIG, the support element 213 is particularly preferably designed in a disk-shaped manner, particularly preferably in the form of a circular disk, from which the coupling element 211 protrudes in the center.

[0063] Furthermore, the coupling part 21 has a connecting element 216. The connecting element 216 is arranged on the side of the support element 213 opposite the coupling element 211 and is designed as a supporting bolt that protrudes from the lower side 215 of the support element 213 facing the switch box, so that the connecting element 216 extends in a direction facing the fastening part 20 when viewed from the support element 213.

[0064] The connecting element 216 extends into the recess 200 of the fastening part 20 and is arranged therein. The coupling part 21 is screwed into the recess 200 using the connecting element 216. To this end, the connecting element 216 has an external thread 217. The recess 200 in the fastening part 20 has a matching internal thread 207 in the wall region 202. For example, the coupling element 211 and the connecting element 216 can each have external threads 212 and 217, each having the same thread size, such as size M8. In particular, the external threads 212 and 217 can have the same direction of rotation and, therefore, can both be right-hand threads, for example.

[0065] In addition, before the coupling part 21 is screwed into the fastening part 21, the external thread 217 of the connecting element 216 and / or the internal thread 207 of the recess 200 can have an interference fit as described above in the general part, thereby achieving a more secure screw connection, by which the coupling part 21 can be prevented from being accidentally screwed out of the fastening part 20.

[0066] After the coupling part 21 has been screwed in, the support element 213 preferably rests with its underside 215 on the fastening part 20. To this end, the fastening part 20 can, 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 the best possible electrical contact can be achieved between the fastening part 20 and the coupling part 21. The edge region 203 can particularly preferably be designed to circumferentially surround the recess 200 in the fastening part 20.

[0067] The support element 211 and the edge region 203 can particularly preferably have the same outer diameter. The upper side 204 of the edge region 203 and the lower side 215 of the support element 211 can both be designed as annular and arranged to coincide with each other. Figure 1A and 1B As can be seen in FIG, the support element 211 and the edge region 203 can each be arranged partially in an opening in the housing of the switching device. In particular, the contact area between the support element 211 and the edge region 203, i.e., the upper side 204 of the edge region 203 and the lower side 215 of the support element 213, can be arranged in the opening of the housing.

[0068] If combined Figure 1A and 1B As shown, the edge region 203 has a fastening edge 205 facing the switch housing, which is connected to the switch housing in a material-fitting manner. The fastening edge 205 can be spaced apart from the wall region 202, for example, by a circumferential groove 204. Figure 3A and 3B , method steps for a method for mounting a fixed contact piece 2 on a switch housing cover 12 are shown, which method steps can be carried out for all fixed contact pieces 2 during the production of a switching device.

[0069] As in Figure 3AAs shown in , the fastening part 20 is introduced into the opening 121 of the switch box cover 12 so that the fastening edge 205 is arranged on the mounting area 122. The mounting area 122 can be formed by a convex ring structure, for example, in the edge area of ​​the opening 121. A hard solder 120 is applied between the mounting area 122 and the fastening edge 205, for example a solder based on silver and / or copper and particularly preferably a silver-copper alloy, such as Ag72Cu28. The switch box cover 12 can be heated, for example in a furnace, with the fastening parts 20 of all fixed contacts 2 arranged in this way, so that a gas-tight connection is formed between the switch box cover 12 and the fastening part 20 by the melted and re-solidified hard solder 120. Subsequently, as in Figure 3B As indicated in , the coupling portion 21 can be screwed into each fastening portion 20 .

[0070] Particularly preferably, the connection part 21 and the fastening part 20 are made of the same material, for example, from or made of metal, preferably copper or a copper alloy that is oxygen-free. In the installed state, i.e., when the fixed contact 2 is fastened to the switch box, the fastening part 20 can have a lower hardness than the connection part 21 due to the brazing process. Due to the high temperatures typically encountered during brazing, such as 800°C or higher, the material of the fastening part 20 can become softer after brazing due to solid-state physical processes. However, since the connection part 21 is not subjected to the brazing process but is screwed in after brazing, it can retain its original hardness.

[0071] The fastening part 20 is thus welded to the switch housing cover and can become softer in the process, while the connecting part 21 made of the same material remains untreated since it is only fastened later. Figure 2E The T-shape of the stiffer coupling part 21, which can be seen in the cross section, facilitates force coordination with the fastening part 20 and prevents shear forces that could later act on the coupling element 211 from damaging the internal thread 207 of the fastening part 20 through leverage. It has been shown that even at relatively low pull-in torques of approximately 4 Nm, the contact resistance added by the two-part shape of the fixed contact 2 is negligible.

[0072] In the following Figures 4 to 8B , an improved solution of the fixed contact 2 according to another embodiment is shown, which can improve the permanent connection between the fastening part 20 and the coupling part 21. Figures 4 to 8B Only the elements described are provided with reference numerals. The described measures can be used individually or in combination.

[0073] As in Figure 4As shown in FIG, the connecting material 23 can be arranged between the external thread 217 of the connecting element 216 of the coupling part 21 and the internal thread 207 of the recess 200 of the fastening part 20, as indicated by the dashed area. The connecting material 23 can include an adhesive or can be an adhesive, for example, using or made of an acrylate, such as methacrylate or cyanoacrylate. The adhesive can harden after the coupling part 21 is mounted on the fastening part 20 and prevent the coupling part 21 from being accidentally unscrewed.

[0074] As in Figure 5 As shown in FIG, connecting material 24 can be arranged in recess 200 below connecting element 216 of connecting element 21. For this purpose, recess 200 particularly preferably has a depth greater than the height of connecting element 216 measured from underside 215 of support element 213, so that when connecting part 21 is fully screwed into fastening part 20, a cavity remains below connecting element 216, in which connecting material 24 can be arranged. Connecting material 24 can include or consist of an adhesive, such as the adhesives described above, or particularly preferably, soft solder. Soft solder can be arranged, for example, in the form of solder pellets, in recess 200 of fastening part 20 already fastened to the switch housing. After screwing in connecting part 21, the soft solder can be melted by heating, for example, in a furnace, the temperature required for this being significantly lower than during a brazing process and without softening connecting part 21. The soft solder may preferably be lead-free and, for example, based on Bi, Sn and / or Sb or based on Sn and Ag and / or Cu, as described above in the general section. 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. For example, the flux may improve the wetting properties of the soft solder.

[0075] As in Figure 6 , the connecting material 25 can be arranged between the underside 215 of the support element 213 of the coupling part 21 and the upper side 204 of the edge region 203 of the fastening part 20. For example, the connecting material 25 can include or consist of an adhesive or, particularly preferably, a soft solder as described above.

[0076] For Figure 5 and 6In the refinement shown in FIG, before the connection part 21 is screwed onto the fastening part 20, connecting material 24, 25, preferably in the form of soft solder, can be applied either into the recess 200 near the thread or at the outer edge, i.e., onto the support surface formed by the upper side 204 of the edge region 203. For example, after the connection part 21 is installed, the solder containing flux can be brought to its melting temperature, preferably less than or equal to 300°C, resulting in melting and, subsequently, a secure connection. The low melting temperature of the soft solder prevents a reduction 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 is typically maintained at less than 160°C, which prevents the soft solder from remelting. Introducing the connecting material 25 at the outer edge has the advantage that it increases the torque required to release the soft solder connection.

[0077] In addition, as in Figure 7A and 7B As shown in , the upper side 204 of the edge region 203 of the fastening part 20 and / or the lower side 215 of the support element 213 of the coupling part 21 can have surface structures 209, 219, such as knurling and / or roughening, which can be produced, for example, by sandblasting. The surface structures 209, 219 can be particularly preferably provided between the lower side 215 of the support element 213 and the upper side 204 of the edge region 203 in conjunction with the connecting material 25.

[0078] As in Figure 8A and 8B As shown in FIG, the support element 213 of the connecting part 21 can be welded to the edge region 203 of the fastening part 20. After the connecting part 21 is screwed to the fastening part 20, the contact edge is welded around or partially at the edge. In particular, the supporting element 213 and the edge region 203 can be connected to each other by means of a weld seam 26 on the outside of the contact region formed by the lower side 215 of the supporting element 213 and the upper side 204 of the edge region 203. Figure 8A The dashed area in the figure indicates that the weld seam 26 can particularly preferably be completely circumferential. The weld seam 26 can particularly preferably be formed by laser welding. Welding has the advantage of short processing times. Furthermore, a high degree of safety can be achieved against accidental loosening of the coupling part 21 from the fastening part 20 during use of the switching device.

[0079] The surfaces of the parts to be connected can be prepared in such a way that the laser beam can efficiently introduce energy and reflection of the beam can be prevented. Figure 8B As indicated in FIG, an absorption element 27 can be arranged in the welding region for this purpose, which absorption element can be formed, for example, by a suitable pigment, lacquer or roughening.

[0080] The features and embodiments described in conjunction with the figures can be combined with one another according to other embodiments, even if not all combinations are explicitly described. Furthermore, the embodiments described in conjunction with the figures can alternatively or additionally have further features according to the description in the general part.

[0081] The invention is not limited to the exemplary embodiments by the description based on the exemplary embodiments. On the contrary, the invention encompasses every novel feature and every combination of features, including in particular every combination of features in the patent claims, even if this feature or this combination itself is not explicitly specified in the patent claims or the exemplary embodiments.

[0082] Reference Signs List

[0083] 1 Housing

[0084] 2 Fixed contacts

[0085] 3 Insulators

[0086] 4 Contact bridge

[0087] 5 Armature

[0088] 6 cores

[0089] 7-axis

[0090] 8 coils

[0091] 9 Yoke

[0092] 10 Spring

[0093] 11 Switch Box

[0094] 12 Switch box cover

[0095] 13 Switch box bottom

[0096] 14 Airtight Area

[0097] 15 Interior Space

[0098] 16 permanent magnets

[0099] 17 Gas filling pipe

[0100] 20 Fastening part

[0101] 21 Connection part

[0102] 23, 24, 25 connection materials

[0103] 26 Weld

[0104] 27 Absorption element

[0105] 28 Laser

[0106] 34 contact spring

[0107] 100 switchgear

[0108] 101, 121 opening

[0109] 122 Installation Area

[0110] 123 Fastening Edges

[0111] 120 Hard solder

[0112] 200 recess

[0113] 201 bottom area

[0114] 202 Wall Area

[0115] 203 Marginal Area

[0116] 204 upper side

[0117] 205 Fastening edge

[0118] 206 slots

[0119] 207 internal thread

[0120] 208 contact surface

[0121] 209 surface structure

[0122] 211 Connecting elements

[0123] 212 external thread

[0124] 213 Support element

[0125] 214 upper side

[0126] 215 lower side

[0127] 216 Connecting elements

[0128] 217 external thread

[0129] 219 surface structure.

Claims

1. A switching device (100) having at least one fixed contact (2) which projects into a switch box (11), wherein - the at least one fixed contact has a fastening portion (20) and a coupling portion (21), - the fastening portion is fastened to the switch box, and - The coupling portion protrudes into a recess (200) of the fastening portion. 2 . The switch device according to claim 1 , wherein the coupling portion and the fastening portion are made of the same material. 3 . The switch device according to claim 2 , wherein the fastening portion has a lower hardness than the coupling portion. 4 . The switching device according to claim 1 , wherein the fastening portion is configured cup-shaped and the recess is configured as a blind hole.

5. The switching device according to claim 1, wherein the connecting part has a connecting element (211), which is arranged outside the housing (1) of the switching device and is formed by a supporting bolt.

6. Switchgear according to the preceding claim, wherein the coupling portion has a supporting element (213) from which the coupling element extends.

7. Switchgear according to the preceding claim, wherein the support element has an underside (215) facing the switch box, with which underside the coupling part rests on the fastening part.

8. Switching device according to the preceding claim, wherein the fastening section has an edge region (203) with an upper side (204) on which the underside of the support element rests.

9. A switching device according to claim 8, wherein the switching device (100) has a housing (1), the switch box (11) is arranged in the housing (1), and the upper side (204) of the edge area (203) and the lower side (215) of the supporting element (213) are arranged in an opening (101) of the housing (1).

10. The switching device according to claim 8 or 9, wherein an upper side of an edge region of the fastening part and / or an underside of a support element of the coupling part has a surface structure (209, 219). The switching device according to claim 10 , wherein the surface structure has knurling and / or roughening.

12. The switching device according to claim 8, wherein a connecting material (25) is arranged between the underside of the support element and the upper side of the edge region.

13. Switchgear according to the preceding claim, wherein the connecting material comprises a soft solder. 14 . The switching device according to claim 8 , wherein the support element is welded to the edge region. 15 . The switching device according to claim 8 , wherein the edge region has a fastening edge facing the switch housing, the fastening edge being connected to the switch housing in a materially bonded manner.

16. The switching device according to any of the preceding claims, wherein the coupling part projects into a recess of the fastening part with a connecting element (216) and is screwed into the recess with the connecting element.

17. Switchgear according to the preceding claim, wherein the connecting element has an external thread (217) and the recess in the fastening portion has an internal thread (207).

18. Switchgear according to the preceding claim, wherein the outer thread and / or the inner thread has an interference fit before the coupling part is screwed into the fastening part.

19. The switching device according to any of the preceding claims, wherein a connecting material (23) comprising an adhesive is arranged between the outer thread and the inner thread.

20. The switching device as claimed in claim 1, wherein a connecting material (24) comprising soft solder is arranged in a recess below the connecting element.

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