SWITCHING DEVICE

Description

[0001] A switching device is specified.

[0002] The switching device is designed, in particular, as an electromagnetically acting, remotely operated switch operable by an electrically 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 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 for such switching devices, particularly power contactors, is the opening and disconnecting of battery circuits, for example in motor vehicles such as electric or partially electric vehicles. These can be, for example, purely battery-powered vehicles (BEV: "Battery Electric Vehicle"), hybrid electric vehicles (PHEV: "Plug-in Hybrid Electric Vehicle") that can be charged via a power outlet or charging station, and hybrid electric vehicles (HEV: "Hybrid Electric Vehicle"). In this case, both the positive and negative contacts of the battery are usually disconnected using a power contactor. This disconnection occurs during normal operation, for example, when the vehicle is at rest, as well as in the event of a malfunction such as an accident or similar. The main task of the power contactor is to de-energize the vehicle and interrupt the flow of current.

[0004] A key feature of such contactors is the ability to quickly and reliably extinguish the applied load in all installation positions, even when installed upside down, where gravity does not act in the opening direction. In addition, rapid opening of the contacts is desirable to prevent the formation of switching arcs.

[0005] To achieve the reset movement of a contactor, return springs are used. These springs are compressed during the closing process, store a force during operation, and then use this force to push the contacts apart again at the moment of disconnection. Typically, linear springs are used for this purpose, i.e., springs whose spring constant and counterforce are linear over the entire spring travel. This has the disadvantage that a great deal of energy is required from the beginning of the closing process to activate the contactor and to even overcome the counterforce of the return spring.

[0006] The publication DE 10 2015 121 033 describes the use of two dependent springs as a return spring mechanism. This has the advantage that at the beginning of the switching process, the moving system is only counteracted by a small counterforce in the form of a first, lighter spring. After a certain distance, the first, lighter spring is blocked and a second, harder spring is compressed. The latter is now easier because the moving system is already in motion and can therefore more easily overcome the counterforce of the harder spring. In the final state, the same counterforce can still be stored for the switch-off process, even though less energy was required for the switch-on process. However, additional individual components must be used for this, namely, in addition to the two springs, a separator and a stop for the first spring.

[0007] The document DE 1 590 688 B1 describes a relay device that has a contact plate on an armature, by means of which contacts can be electrically connected. The armature can be moved in a direction opposite to the direction of gravity by means of a coil. When current no longer flows through the coil, gravity pulls the armature back down. A spring can be used to minimize contact rebound when the contact plate strikes the contacts.

[0008] The document DE 20 2018 101 604 U1 describes a key module for a key on a keyboard.

[0009] The document DE 35 37 598 A1 describes an electromagnetic switch.

[0010] The document DE 697 14 895 T2 describes an encapsulated contact arrangement with adjustable contact spacing.

[0011] The document DE 20 320 532 U1 describes a switching contact system for an electrical switch.

[0012] At least one object of certain embodiments is to provide a switching device, particularly preferably a switching device, in which the described disadvantages can be reduced or even prevented.

[0013] This object is achieved by an object according to the independent patent claim. Advantageous embodiments and developments of the object are characterized in the dependent claims and will further become apparent from the following description and the drawings.

[0014] According to one embodiment, a switching device has at least one fixed contact and at least one movable contact. The at least one fixed contact and the at least one movable contact are provided and configured to switch a load circuit connectable to the switching device on and off. The movable contact is movable in the switching device between a non-switching state and a switching state of the switching device in such a way that the movable contact is spaced from the at least one fixed contact in the non-switching state of the switching device and is thus galvanically isolated, and in the switching state has a mechanical contact with the at least one fixed contact and is thus galvanically connected to the at least one fixed contact.Particularly preferably, the switching device has at least two fixed contacts which are arranged separately from one another in the switching device and which can thus be electrically connected to one another or electrically separated from one another by the movable contact, depending on the state of the movable contact.

[0015] Here and below, the non-switching state is referred to as the first switching state, and the switching state is referred to as the second switching state of the switching device. During the transition from the first to the second switching state, at least one intermediate state is passed through. During the reverse transition from the second switching state to the first switching state, the same intermediate state can be passed through. It is also possible that a different intermediate state is passed through.

[0016] According to a further embodiment, the switching device has a housing in which the movable contact and the at least one fixed contact or the at least two fixed contacts are arranged. The movable contact can in particular be arranged entirely in the housing. The fact that a fixed contact is arranged in the housing can in particular mean that at least the contact area of ​​the fixed contact, which is in mechanical contact with the movable contact in the second switching state, i.e. in the switched-on state, is arranged within the housing. In order to connect a supply line of a circuit to be switched by the switching device, a fixed contact arranged in the housing can be electrically contactable from the outside, i.e. from outside the housing.For this purpose, a fixed contact arranged in the housing can protrude with a part out of the housing and have a connection option for a 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 entirely in the gas atmosphere in the housing, and that at least parts of the fixed contact(s), such as the contact area(s) of the fixed contact(s), are arranged in the gas atmosphere in the housing. Accordingly, the switching device can particularly preferably be a gas-filled switching device, such as a gas-filled contactor.

[0018] According to a further embodiment, the contacts—that is, the entire movable contact and at least parts of the fixed contact(s)—are arranged in a switching chamber within the housing, in which the gas, i.e., at least part of the gas atmosphere, is located. The gas can preferably have a proportion of at least 50% H 2 . In addition to hydrogen, the gas can contain an inert gas, particularly preferably N 2 and / or one or more noble gases.

[0019] According to a further embodiment, the movable contact is movable by means of a magnetic armature. For this purpose, the magnetic armature can in particular have an axle which is connected at one end to the movable contact in such a way that the movable contact is movable by means of the axle, i.e. is moved by the axle when the axle moves. The axle can in particular protrude into the switching chamber through an opening in the switching chamber. The magnetic armature can be movable by a magnetic circuit. In particular, the magnetic circuit can have a yoke which has an opening through which the axle of the magnetic armature protrudes. The axle can preferably comprise or be made of stainless steel. The yoke can preferably comprise or be made of pure iron or a lightly doped iron alloy.

[0020] The movable contact can be moved, in particular, from the first switching state to the second switching state by means of the magnetic armature. In other words, the transition from the first to the second switching state can be brought about by the magnetic armature being moved by a magnetic force caused by the magnetic circuit. The magnetic armature further comprises a spring which is designed to store energy during the transition from the first switching state to the second switching state, which energy can return the movable contact from the second switching state to the first switching state. This can mean, in particular, that the magnetic armature and thus the movable contact are moved back by the spring in the absence of the magnetic force caused by the magnetic circuit.The spring can be compressed in particular by the movement of the magnet armature from the first to the second switching state, which is caused by the magnetic force generated by the magnetic circuit.

[0021] According to the invention, the spring has a first spring region with a first spring constant and a second spring region with a second spring constant that is greater than the first spring constant. The spring thus has two regions that are characterized by different spring hardness and, accordingly, by different response behavior to an external force. The spring can therefore particularly preferably be designed as a non-linear spring. Due to the smaller first spring constant compared to the second spring constant, the first spring region is compressed more strongly than the second spring region, at least at the beginning of the switching process brought about by the magnetic circuit. According to the invention, the spring is designed such that during the transition from the first switching state to the intermediate state, only the first spring region is compressed.

[0022] The intermediate state can preferably correspond to a state of the spring from which, upon further compression of the spring, the first spring region is no longer compressed, or at least no longer significantly compressed. This can be achieved, for example, by the spring being designed such that the spring windings in the first spring region block each other upon reaching the intermediate state upon further compression of the spring. Accordingly, the spring can be designed such that the first spring region is blocked during a transition from the intermediate state to the second switching state. For example, the first spring region can be fully compressed from the intermediate state onwards, so that the windings of the first spring region abut one another upon reaching the intermediate state.

[0023] The spring can further be configured such that the second spring region is compressed during a transition from the intermediate state to the second switching state. In particular, only the second spring region can be compressed. This can particularly preferably be the case if, as described above, the first spring region is blocked upon further compression of the spring once the intermediate state is reached. The first spring region then acts as a stop for the second spring region.

[0024] Due to the different spring constants, the different spring regions respond preferentially one after the other to an external force which is caused by the switching movement of the armature and which compresses the spring. This means that when the armature is actuated, i.e. when transitioning from the first switching state to the second switching state, a first force determined by the first spring region must first be overcome, and only later a second force determined by the second spring region must be overcome. Since the first force is smaller than the second force, only a small counterforce must be overcome at the beginning of the switching process. Only when the armature is already moving and the described intermediate state has been reached does a higher counterforce have to be overcome.At this point, however, it may be advantageous for the moving system, i.e. essentially the magnetic armature with the moving contact, to have already gained sufficient speed to overcome this higher resistance.

[0025] If the magnetic force generated by the magnetic circuit is switched off, the second spring region can generate a sufficiently high restoring force, which moves the movable system back toward the first switching state. In this case, the spring's expansion can be reversed to the previously described compression. In particular, it may be possible for the described spring to achieve a lower pull-in energy with the same or even higher restoring force than when using conventional linear springs.

[0026] According to a further embodiment, the first and second spring regions have different windings, for example, in particular windings of different tightness. This allows the different spring regions to be produced when using the same material for the entire spring, for example conventional spring steel. Depending on the desired spring constants and spring travel, it may be possible for the first and second spring regions to have, for example, a different number of windings. Furthermore, it may also be possible for the first and second spring regions to have the same number of windings. Furthermore, the first and second spring regions can have different spring travel. Alternatively, the same spring travel is also possible.

[0027] The transition from the first to the second spring region can be abrupt. This can mean that the spring has a constant first winding pitch in the first spring region and a constant second winding pitch in the second spring region, which is different from the first winding pitch, and the two spring regions are directly adjacent to one another. Alternatively, it can also be possible for the transition from the first to the second spring region to be continuous. In this case, the spring can have a constant first winding pitch in the first spring region and a constant second winding pitch in the second spring region which is different from the first winding pitch, with a transition region being present between the first and second spring regions in which the winding pitch changes from the first to the second winding pitch over several windings.

[0028] Furthermore, it may also be possible for the spring to have at least a third spring region with a third spring constant that is greater than the second spring constant. The same applies to the design and behavior of the third spring region in relation to the second spring region as described above for the first and second spring regions. The second spring region may, for example, be arranged between the first spring region and the third spring region. Furthermore, it may also be possible for the first spring region to be arranged between the second and third spring regions. In addition, there may also be more than three spring regions with different spring constants.

[0029] Further advantages, advantageous embodiments and further developments emerge from the exemplary embodiments described below in conjunction with the figures.

[0030] They show: Figures 1A and 1Bschematic representations of an example of a switching device, Figure 2 a schematic representation of a part of a switching device according to an embodiment, Figures 3A to 3C schematic representations of different states of a spring of a switching device according to a further embodiment, Figures 4A to 4C schematic representations of parts of a switching device according to a further embodiment and Figures 5A and 5B schematic representations of springs of a switching device according to further embodiments.

[0031] In the exemplary embodiments and figures, identical, similar, or similarly functioning elements may be provided with the same reference numerals. The illustrated elements and their relative sizes are not to be considered to scale; rather, individual elements, such as layers, components, structural elements, and regions, may be exaggerated for clarity and / or clarity.

[0032] In the Figures 1A and 1B An example of a switching device 100 is shown, which can be used, for example, to switch strong electrical currents and / or high electrical voltages and which can be a relay or contactor, in particular a power contactor. In Figure 1A a three-dimensional sectional view is shown, while in Figure 1B a two-dimensional sectional view is shown. The following description refers equally to the Figures 1A and 1B The geometries shown are only exemplary and not limiting and can also be designed alternatively.

[0033] The switching device 100 has two fixed contacts 2, 3 and one movable contact 4 in a housing 1. The movable contact 4 is designed as a contact plate. The fixed contacts 2, 3, together with the movable contact 4, form the switching contacts. The housing 1 primarily serves as contact protection for the components arranged inside and comprises or is made of a plastic, for example, polybutylene terephthalate (PBT) or glass-filled PBT. The contacts 2, 3, 4 can, for example, be made of or with Cu, a Cu alloy, or a mixture of copper with at least one other metal, for example Wo, Ni, and / or Cr.

[0034] In the Figures 1A and 1BThe switching device 100 is shown in a first switching state, which corresponds to a rest state in which the movable contact 4 is spaced from the stationary contacts 2, 3, so that the contacts 2, 3, 4 are galvanically isolated from one another. The illustrated design of the switching contacts and in particular their geometry are purely exemplary and not to be understood as limiting. Alternatively, the switching contacts can also be designed differently. For example, it may be possible for only one of the switching contacts to be stationary.

[0035] The switching device 100 has a movable magnetic armature 5, which essentially performs the switching movement. The magnetic armature 5 has a magnetic core 6, for example, made of or made of a ferromagnetic material. Furthermore, the magnetic armature 5 has a shaft 7, which is guided through the magnetic core 6 and is firmly connected to the magnetic core 6 at one end of the shaft. At the other end of the shaft, opposite the magnetic core 6, the magnetic armature 5 has the movable contact 4, which is also connected to the shaft 7. The shaft 7 can, for example, be made of or made of stainless steel.

[0036] The magnetic core 6 is surrounded by a coil 8. A current flow in the coil 8, which can be switched on from the outside, generates a movement of the magnetic core 6 and thus of the entire magnetic armature 5 in the axial direction due to a magnetic force until the movable contact 4 contacts the fixed contacts 2, 3. The magnetic armature 5 thus moves from the position in the first switching state, which corresponds to the idle state, i.e., the isolating, i.e., non-switching state, to a second position in a second switching state of the switching device 100, which corresponds to the active, i.e., switching state. In the second switching state, i.e., the active state, the contacts 2, 3, 4 are galvanically connected to one another. In another embodiment, the magnetic armature 5 can alternatively also perform a rotary movement. The magnetic armature 5 can, in particular, be designed as a tension rod or a hinged armature.To guide the shaft 7 and thus the magnet armature 5, the switching device 100 has a yoke 9, which may be made of pure iron or a lightly doped iron alloy and forms part of the magnetic circuit. The yoke 9 has an opening through which the shaft 7 is guided. If the current flow in the coil 8 is interrupted, the magnet armature 5, in the example shown, is moved back to the first position by one or more springs 10. The switching device 100 is then back in the rest state, in which the contacts 2, 3, 4 are open.

[0037] When contacts 2, 3, 4 are opened, an arc can occur that can damage the contact surfaces. This can create the risk that contacts 2, 3, 4 will "stick" to one another due to welding caused by the arc and can no longer be separated. To prevent the formation of such arcs or at least to assist in extinguishing any arcs that occur, contacts 2, 3, 4 are arranged in a gas atmosphere, so that switching device 100 is designed as a gas-filled relay or gas-filled contactor. For this purpose, contacts 2, 3, 4 are arranged within a switching chamber 11, formed by a switching chamber wall 12 and a switching chamber base 13, in a hermetically sealed part of housing 1. Housing 1, and in particular the hermetically sealed part of housing 1, completely surrounds magnet armature 5 and contacts 2, 3, 4.The hermetically sealed part of the housing 1 and thus also the switching chamber 11 are filled with a gas 14. The gas 14, which can be filled through a gas filling nozzle 15 during the manufacture of the switching device 100, can particularly preferably contain hydrogen, for example with 50% or more H 2 in an inert gas or even with 100% H 2 , since hydrogen-containing gas can promote the extinguishing of arcs. Furthermore, so-called blowout magnets (not shown) can be present inside or outside the switching chamber 11, i.e. permanent magnets that cause an extension of the arc gap and can thus improve the extinguishing of the arcs. The switching chamber wall 12 and the switching chamber base 13 can, for example, be made with or from a metal oxide such as Al 2 O 3.

[0038] In the Figures 1A and 1BA conventional spring arrangement with two springs 10 is shown, which, when the magnetic field is switched off, cause the switching device 100 to return from the second switching state to the first switching state. However, compared to using only one spring, additional components are required.

[0039] In Figure 2 a section of a switching device 100 according to an embodiment of the invention is shown. Components and features of the switching device that are used in conjunction with the Figure 2 not shown and / or described may be used as described in connection with the Figures 1A and 1B described.

[0040] Compared to the switching device 100 of the Figures 1A and 1B indicates the Figure 2The switching device 100 shown has a spring 10 having a first spring region 10-1 with a first spring constant and a second spring region 10-2 with a second spring constant. The spring constants of the spring regions 10-1 and 10-2 are different. Purely by way of example, the second spring constant is greater than the first spring constant, so that, in simple terms, the first spring region 10-1 is softer than the second spring region 10-2. The spring 10 is thus a non-linear spring. The magnetic core 6 and the yoke 9 each form a stop for the spring 10, which is installed freely but also under tension in the first switching state. For example, the spring 10 can be made of spring steel, for example stainless steel 1.4305, and when relaxed can have a length in a range greater than or equal to 7 mm and less than or equal to 20 mm, for example approximately 9 mm, and a diameter in the range of approximately 4 mm.The diameter of the spring 10 also depends on the diameter of the shaft 7, which extends through the coils of the spring 10 as shown. The operation of the spring 10 is explained in connection with the . Figures 3A to 3C described.

[0041] In connection with the Figures 3A to 3C Various states of the spring 10 are shown, as they occur during the switching operations of the switching device 100. The windings of the spring regions 10-1, 10-2 are indicated as zigzag lines, and the different spring constants are indicated by the different line types. The indicated number of windings of the spring regions 10-1, 10-2 is to be understood purely as an example. In the illustrated embodiment, the spring constant of the first spring region 10-1 is smaller than the spring constant of the second spring region 10-2.

[0042] The spring 10 is compressed during the switching process caused by the magnetic circuit, i.e. during the transition from the first switching state, the open state, to the second switching state, the closed state, and can thus store energy which can return the movable contact from the second switching state to the first switching state when the force caused by the magnetic circuit is switched off.

[0043] In Figure 3AThe spring 10 is shown in the first switching state, in which the spring 10 is held under tension between the stops formed by the magnetic core and the yoke. If a switching current is applied to the coil of the magnetic circuit, the magnet armature moves towards the fixed contacts, so that the spring 10 is compressed. Since the spring constant of the first spring region 10-1 is smaller than that of the second spring region 10-2, initially essentially and particularly preferably exclusively the first spring region 10-1 is compressed. This continues until the first spring region 10-1 is compressed to such an extent that the spring windings of the first spring region 10-1 block each other upon reaching an intermediate state during further compression of the spring 10. This intermediate state is shown in Figure 3Bshown, in which the first spring region 10-1 is substantially or particularly preferably completely compressed and thus blocked. In the further course of the compression of the spring 10, from reaching the intermediate state until reaching the second switching state, substantially and particularly preferably exclusively the second spring region 10-2 is compressed. Since the movable system, i.e. essentially the magnet armature with the movable contact, has already gained sufficient speed when passing through the intermediate state, it is easily possible to overcome the higher resistance of the second spring region 10-2 compared to the first spring region 10-1. In Figure 3C The spring 10 is shown in the second switching state, in which the second spring region 10-2 is also compressed. Depending on the design of the spring 10 and in particular the spring travel of the second spring region 10-2, this can be fully or only partially compressed.

[0044] If the magnetic force generated by the magnetic circuit is switched off, a sufficiently high restoring force can be generated at least by the second spring region 10-2, which moves the movable system back toward the first switching state. In particular, the extension of the spring 10 during the return to the first switching state can be reversed to the described compression.

[0045] By selecting the spring material as well as the number and pitch of the windings of the first and second spring regions 10-1, 10-2, it is possible to adjust the spring constants and spring travels of the spring regions 10-1, 10-2 as desired in order to optimally achieve both switching directions. Particularly preferably, the first and second spring regions 10-1, 10-2 have different windings, for example, in particular windings of different tightness or different winding pitches. This makes it possible to achieve different spring constants when using the same material for the entire spring. Depending on the desired spring constants and spring travels, it may be possible for the first and second spring regions 10-1, 10-2 to have different numbers of windings, for example. Furthermore, it may also be possible for the first and second spring regions 10-1, 10-2 to have the same number of windings.Furthermore, the first and second spring regions 10-1, 10-2 can have different spring travels. Alternatively, the same spring travel is also possible.

[0046] The transition from the first spring area 10-1 to the second spring area 10-2 can be as shown in the Figures 3A to 3Cshown abrupt. The spring 10 can have a constant first winding spacing in the first spring region 10-1 and a constant second winding spacing in the second spring region 10-2, which is different from the first winding spacing, wherein the two spring regions 10-1, 10-2 are directly adjacent to one another, so that the transition from the first to the second spring region 10-1, 10-2 is abrupt. Alternatively, it can also be possible for the transition from the first to the second spring region 10-1, 10-2 to be continuous, i.e. for there to be a transition region between the first and second spring region 10-1, 10-2, in which the winding spacing changes over several windings from the first to the second winding spacing.

[0047] In connection with the Figures 4A to 4C another embodiment is shown, which is a modification of the one shown in Figure 2 shown embodiment. Figure 4Ashows part of the switching device, while in the Figures 4B and 4C the spring is shown in two different states during a switching operation. Here again, components and features of the switching device that are used in connection with the embodiment of the Figures 4A to 4C not shown and / or described, as described in connection with the previous figures. For the sake of better recognition, Figure 4A the magnetic core 6 and the yoke 9 are shown cut away. As in connection with the Figure 2 As described, the spring 10 is designed as a non-linear spring with a first and a second spring region 10-1, 10-2 with different spring constants.

[0048] In comparison to the previous embodiment, in which the axis 7 is guided directly through the yoke 9, the yoke 9 in the embodiment of the Figures 4A to 4Can opening 29 in which a barrel liner 20 is arranged. The barrel liner 20 comprises a low-friction, hydrogen-compatible plastic, in particular PE, glass-filled PBT, and / or preferably PEEK. The barrel liner 20 is particularly preferably formed from PEEK, which, with a melting point of 335°C, is advantageously high-temperature resistant with respect to the temperatures typically encountered in gas-filled shooters. The shaping of the barrel liner 20 described below can be produced by a manufacturing process such as injection molding.

[0049] To guide the axle 7, the bushing 20 has a guide opening 21, which is in particular cylindrical and in which the axle 7 is arranged, such that the axle 7 projects through the bushing 20 in the guide opening 21. The guide opening 21 and the axle 7 preferably have a very tight fit in order to enable precise guidance of the axle 7. The guide opening 21 therefore has a diameter that is only very slightly larger than the diameter of the axle 7. As can easily be seen, the axle 7 is guided to the yoke 9 in the bushing 20 without contact. The lack of contact between the axle 7 and the yoke 9 prevents abrasion between the axle 7 and the yoke 9, which could occur with an increasing number of switching operations due to the materials used for the axle 7 and the yoke 9.

[0050] The bushing 20 is secured in the opening 29 of the yoke 9 by a press fit. As shown, the bushing 20 does not have to fill the entire opening 29 of the yoke 9. To this end, the bushing 20 has an outer surface 22 that is at least partially in contact with the inner wall of the opening 29 of the yoke 9. The press fit fixes the bushing 20 in the opening 29 of the yoke 9 independently of the movement of the axle 7.

[0051] The bushing 20 can rest with the entire outer surface 22 and / or over the entire circumference against the inner surface of the opening 29 of the yoke 9. However, it may be more advantageous if, as in Figure 4Ais shown, at least one channel 23 is formed in the outer surface 22. Particularly preferably, the at least one channel 23 can run parallel to the axis 7. The at least one channel 23 preferably runs from a side facing away from the movable contact to a side of the bushing 20 facing the movable contact and forms an intermediate space extending through the opening 29 of the yoke 9 between the inner wall of the opening 29 and the outer surface 22 of the bushing 20, which intermediate space enables gas exchange through the opening 29 of the yoke 9. When the magnet armature moves during a switching operation of the switching device, gas can thus flow through such a channel 23 and thus follow the movement of the movable parts, so that no overpressure or underpressure can build up in a partial area in the gas volume, which could lead to a delay in the switching operation.

[0052] In the illustrated embodiment, the bushing 20 has a plurality of channels 23 in the outer surface 22. Four channels 23 are shown purely as an example, but more or fewer channels may be present. As shown, the channels 23 are preferably arranged at regular intervals on the outer surface 22 of the bushing 20 around the guide opening 21 and thus around the axis 7, and all run parallel to the axis 7. Between the channels 23, the outer surface 22 of the bushing 20, which is in contact with the inner wall of the opening 29 of the yoke 9, ensures a press fit, as described above, and thus fixes the bushing 20 in the opening 29 of the yoke 9.

[0053] As in Figure 4AAs further shown, the bushing 20 can, in at least one switching state of the switching device and preferably permanently, protrude into the opening 26 in the magnetic core 6 in which the axle 7 is fastened. In particular, the bushing 20 can also form a stop for the spring 10, while, as in the previous embodiment, the magnetic core 6 forms the other stop for the spring 10.

[0054] In Figure 4B The spring 10 is shown in the first switching state, i.e., in the rest state of the switching device. The total length L of the spring 10 is approximately 9 mm in the relaxed state with a diameter of approximately 4 mm, and in the installed state in the first switching state, purely by way of example, 8.1 mm. The first spring region 10-1 has 8 windings and a spring travel of 1 mm in the illustrated embodiment. The second spring region 10-2 has two windings and a spring travel of several millimeters. Figure 4C the spring 10 is in the Figure 3Bcorresponding intermediate state in which the first spring region 10-1 is fully compressed, so that the coils of the first spring region 10-1 block each other. In this state, according to the present embodiment, the spring 10 has a length L of 7.1 mm. Upon further compression of the spring 10 to achieve the second switching state, as described in connection with the Figures 3A to 3C described, only the second spring region 10-2 with the larger spring constant is compressed.

[0055] As an alternative to the illustrated embodiments with a spring 10 having two spring regions 10-1, 10-2, the spring 10 may also have more than two spring regions. For example, it may be possible for the spring 10, as shown in the Figures 5A and 5Bis indicated, has at least one third spring region 10-3 with a third spring constant that is greater than the second spring constant of the second spring region 10-2. The same applies to the design and behavior of the third spring region 10-3 in relation to the second spring region 10-2 as previously described for the first and second spring regions 10-1, 10-2. The second spring region 10-2 can, for example, be arranged between the first spring region 10-1 and the third spring region 10-3, as in Figure 5A Furthermore, it may also be possible for the first spring region 10-1 to be arranged between the second and third spring regions 10-2, 10-3, as shown in Figure 5B is shown. In addition, more than three spring regions with different spring constants can be present.

[0056] The features and exemplary embodiments described in conjunction with the figures can be combined with one another according to further exemplary embodiments, even if not all combinations are explicitly described. Furthermore, the exemplary embodiments described in conjunction with the figures can alternatively or additionally have further features according to the description in the general part.

[0057] The invention is not limited to the embodiments described in the following. List of reference symbols

[0058] 1 Housing 2, 3 Fixed contact 4 Moving contact 5 Magnet armature 6 Magnetic core 7 Axis 8 Coil 9 Yoke 10 Spring 10-1, 10-2, 10-3 Spring area 11 Switching chamber 12 Switching chamber wall 13 Switching chamber base 14 Gas 15 Gas filling nozzle 20 Liner 21 Guide opening 22 Outer surface 23 Channel 26 Magnetic core opening 29 Yoke opening 100 Switching device L Length

Claims

1. Switching device (100), having at least one stationary contact (2, 3) and a moving contact (4), wherein the moving contact (4) can be moved from a first switching state to a second switching state by means of a magnet armature (5), the magnet armature (5) has a spring (10) which is configured to reset the moving contact (4) from the second switching state to the first switching state, characterized in that the spring (10) has a first spring region (10-1) with a first spring constant and a second spring region (10-2) with a second spring constant which is greater than the first spring constant, and only the first spring region (10-1) is compressed when a changeover is made from the first switching state to an intermediate state.

2. Switching device (100) according to Claim 1, wherein the first spring region (10-1) is blocked during a changeover from the intermediate state to the second switching state.

3. Switching device (100) according to one of the preceding claims, wherein the second spring region (10-2) is compressed when a changeover is made from an intermediate state to the second switching state.

4. Switching device (100) according to one of the preceding claims, wherein only the second spring region (10-2) is compressed when a changeover is made from an intermediate state to the second switching state.

5. Switching device (100) according to one of the preceding claims, wherein the first spring region (10-1) and the second spring region (10-2) have different winding pitches.

6. Switching device (100) according to one of the preceding claims, wherein the first spring region (10-1) and the second spring region (10-2) have different numbers of windings.

7. Switching device (100) according to one of the preceding claims, wherein the first spring region (10-1) and the second spring region (10-2) have different spring travels.

8. Switching device (100) according to one of the preceding claims, wherein the spring (10) has at least one third spring region (10-3) with a third spring constant which is greater than the second spring constant.

9. Switching device (100) according to one of the preceding claims, wherein the magnet armature (5) has a shaft (7) and the shaft (7) projects through the spring (10).

10. Switching device (100) according to the preceding claim, wherein the shaft (7) projects through an opening (29) in a yoke (9), which is part of a magnetic circuit, and a liner (20) composed of a plastic is arranged in the opening (29) of the yoke (9) for guiding the shaft (7).

11. Switching device (100) according to the preceding claim, wherein the liner (20) forms a stop for the spring (10).

12. Switching device (100) according to one of the preceding claims, wherein the contacts (2, 3, 4) are arranged in a switching chamber (11) containing a gas (14) which contains H2.

13. Switching device (100) according to the preceding claim, wherein the gas has an H2 content of at least 50%.