CN117461107A

CN117461107A - Switching device

Info

Publication number: CN117461107A
Application number: CN202280041328.0A
Authority: CN
Inventors: R·舍切特; 于舜; R·莫奇内克
Original assignee: TDK Corp
Current assignee: TDK Corp
Priority date: 2021-06-08
Filing date: 2022-06-03
Publication date: 2024-01-26
Also published as: DE102022104711A1

Abstract

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

Description

Switching device

Technical Field

A switching device is described.

Background

The switching device is in particular designed as an electromagnetically active, remotely operated switch which can be operated by means of an electrical conduction current. The switching means may be activated via a control circuit and may switch the load circuit. The switching device can be designed in particular as a relay or as a contactor, in particular as a power contactor. Particularly preferably, the switching device can be designed as an inflation power contactor.

A possible application of such a switching device, in particular of a power contactor, is the disconnection and separation of a battery circuit, for example in a motor vehicle such as an electric or partly electric motor vehicle.

In the function of a contactor as a safety component, the contactor is typically used in combination with a safety device between a battery (such as a lithium ion battery) and a motor, and must be able to separate the current source from the load in the event of a failure. One serious condition of battery failure is an internal battery short, which, depending on the battery, may lead to a very rapid discharge at a current in the kiloamp range and thus several times the nominal current. In this case, the main task of the contactor is to carry this very high current in a short time, for example in the millisecond range, until the upstream safety device can safely isolate the current or the current decreases due to an increase in the internal resistance of the battery.

The contactor generally has a switching bridge which can be moved by a magnetic drive and which, in the on state of the contactor, for example, electrically connects two stationary main contacts. However, in the event of high short-circuit currents, strong lorentz forces are formed as a result of the magnetization of the conductors, which forces push the switching bridge away from the main contacts. This phenomenon is also called Levitation (Levitation). Due to the levitation, an unwanted arc may form between the main contacts and the bridge, which arc may burn at a very high temperature. Thereby, the contactor may be destroyed.

A magnetic field is formed around the conductor through which the current flows in proportion to the intensity of the current. In existing solutions, the magnetic field caused by the current flowing in the switching bridge is concentrated in the iron parts, whereby these are attracted to each other. This attractive force is also referred to as detent force, which can be used to press the switching bridge more strongly against the main contacts and to prevent the disconnection of the contactor.

For example, publication CN209000835U describes an anti-levitation device in which the switching bridge is biased with a compression spring and held between the insulator and the holding cage. The switching bridge is divided in the middle into two current paths. The two paths are surrounded by an iron plate and an iron clip, respectively, wherein the iron plate is locked at the retaining cage and the iron clip is fixed at the switching bridge.

If the switching bridge is now flown by a current, a corresponding magnetic flux is formed around each current path, which is concentrated in the corresponding iron part. There is an attractive force between these iron parts, which attractive force aims at closing the air gap. With this force, the switching bridge is additionally pressed against the main contacts and thus prevents disconnection, wherein the air gap is unchanged and is specified only by the design of the assembly. Thus, the maximum holding force and thus also the maximum short-circuit current is limited by the following parameters: the force of the compression spring, the cross section of the iron part, the holding force of the magnetic drive, the size of the air gap.

Publication EP2608235B1 and DE102016206130A1 likewise describe anti-levitation devices, in which, however, the switching bridge is not divided into a plurality of current paths and thus only a pair of iron parts is present, respectively.

Disclosure of Invention

At least one task of a particular embodiment is to describe a switching device.

This object is achieved by the subject matter according to the independent patent claims. Advantageous embodiments and developments of the subject matter are specified in the dependent claims and also emerge from the following description and the figures.

According to at least one embodiment, the switching device has at least one fixed contact and at least one movable contact. The movable contact may in particular have a contact bridge or be a contact bridge. In other words, the contact bridge may be the movable contact of the switching device or a part of the movable contact of the switching device. Thus, the characteristics and features of the movable contact described subsequently may be corresponding characteristics and features of the contact bridge, and vice versa. Particularly preferably, the switching device can have a contact device with the movable contact, i.e. the contact bridge.

The at least one fixed contact and the at least one movable contact are arranged and established to: a load circuit connectable to the switching device is turned on and off. In the switching device, the movable contact, i.e. in particular the contact bridge of the contact device, can be correspondingly moved between a non-conductive state and a conductive state of the switching device, such that: the movable contact, i.e. in particular the contact bridge of the contact arrangement, is spaced apart from and thereby galvanically isolated from the at least one fixed contact in the non-conducting state of the switching device and has a mechanical contact with and thereby galvanically connected to the at least one fixed contact in the conducting state. Hereinafter, the conductive state is also referred to as an on state of the switching device, and the non-conductive state is referred to as an off state of the switching device.

It is particularly preferred that the switching device has at least two fixed contacts which are arranged separately from one another in the switching device and which can be electrically conductively connected to one another or electrically separated from one another by the movable contact, i.e. in particular the contact bridge, in the manner described above, depending on the state of the movable contact, i.e. in particular the contact bridge. Preferably, the contact bridge has an upper side with at least one contact region and a lower side opposite the upper side. In the on-state of the switching device, the at least one contact region of the contact bridge is in mechanical contact with the at least one fixed contact, in particular the contact region of the at least one fixed contact. If the switching device has two fixed contacts, for example, the contact bridge can correspondingly have two contact areas.

In the following, the generic term "contact" may particularly refer to all fixed contacts as well as contact bridges or contact devices having such contact bridges. In particular, the contacts may have or may be made of metal, preferably copper or a copper alloy. Furthermore, at least for the contact region, it is also possible, for example: composite materials in the form of a metal matrix material, preferably with or made of copper, and particles distributed therein, preferably with or made of a ceramic material, such as alumina.

According to a further embodiment, the switching device has a housing in which the contact device and the at least one fixed contact or the at least two fixed contacts are arranged. The contact device may in particular be arranged completely in the housing. "fixed contact is arranged in the housing" may mean in particular: at least the contact area of the fixed contact, which in the conductive state is in mechanical contact with the movable contact, is arranged in the housing. For connecting the leads of the electrical circuit to be switched by the switching device, the fixed contacts arranged in the housing may be electrically contact-connectable from the outside, i.e. from the outside of the housing. For this purpose, the fixed contacts arranged in the housing can protrude from the housing with a portion and have connection possibilities for the leads outside the housing.

According to another embodiment, the contacts are arranged in a gaseous atmosphere in the housing. This may mean in particular that: the contact means is arranged entirely in the gaseous atmosphere in the housing; and, furthermore, at least part of the one or more fixed contacts, such as one or more contact areas of the one or more fixed contacts, is arranged in a gaseous atmosphere in the housing. Correspondingly, the switching device may particularly preferably be an inflation switching device, such as an inflation contactor.

According to a further embodiment, the contacts are arranged in a switching chamber within the housing, i.e. the contact means are arranged entirely in the switching chamber within the housing and at least part of the one or more stationary contacts are arranged in the switching chamber within the housing. A gas may be present in the switching chamberI.e. at least a part of the above-mentioned gas atmosphere. The gas may preferably have a proportion of H of at least 20% ₂ And preferably has a proportion of H of at least 50% ₂ . In addition to hydrogen, the gas may be an inert gas, particularly preferably N ₂ And/or one or more noble gases.

According to a further embodiment, the contact bridge can be moved in the switching device by means of a shaft. Particularly preferably, the contact device can be moved in the switching device by means of a shaft. In particular, the contact bridge and particularly preferably the contact device can be movable by means of an armature, which has the shaft. The shaft may be connected at one end directly or indirectly to the contact bridge, so that the contact bridge can be moved by means of the shaft, i.e. also by the shaft when the shaft is moved. It is particularly preferred that the shaft can be connected at one end to the contact device such that the contact device can be moved by means of the shaft, i.e. also by the shaft when the shaft is moved. The shaft can extend into the switching chamber, in particular, through an opening in the switching chamber. The armature may be movable through a magnetic circuit to cause the switching process described above. For this purpose, the magnetic circuit may have a yoke (Joch) with an opening through which the shaft of the armature protrudes. Preferably, the shaft may have or be made of stainless steel. Preferably, the yoke may have or be made of pure iron or a low-doped iron alloy.

According to a further embodiment, the contact device has a holding element. The holding element can be fastened in particular to the shaft. The holding element and thereby the contact device can also be locked to the shaft. This can be achieved, for example, by means of a snap ring or riveting on the shaft. The holding element and thereby the contact device can also be screwed onto the shaft. For this purpose, the holding element can, for example, have a threaded bore or a bore with a threaded, shaped threaded bushing, with which the holding element can be screwed onto the thread of the shaft. In addition, the holding element can be locked to the shaft in this case, for example, also by means of a snap ring and/or a rivet and/or a locking nut. Furthermore, it may also be possible that: the shaft is fixed in the holding element by clamping; and/or a portion of the shaft is formed with the material of the retaining element. In this case, the shaft may preferably have one or more anchoring elements, such as one or more grooves and/or one or more protrusions, which may extend completely or partially around the shaft.

According to a further embodiment, the switching device has an upper yoke element. The upper yoke element is particularly preferably arranged in the switching device separately from the contact bridge and particularly preferably separately from the contact device. In particular, the upper yoke element may be arranged in a non-movable manner and fixed in the switching device.

According to a further embodiment, the switching device has a lower yoke element in addition to the upper yoke element. In particular, the contact device has the lower yoke element. The lower yoke element is therefore preferably part of the contact means.

The upper yoke element or the upper yoke element and the lower yoke element may have or be made of iron, respectively. The upper yoke element or the upper yoke element and the lower yoke element may in particular have or be made of pure iron, respectively.

Preferably, the upper yoke element is not part of the contact device but is arranged in the switching chamber independently of the contact device, as opposed to the lower yoke element, and is thereby arranged in the switching chamber, in particular independently of the lower yoke element, in the case of the contact device having the lower yoke element. It is particularly preferred that the upper yoke element is arranged and locked in an unchangeable manner with respect to its position relative to the at least one fixed contact. The upper yoke element may be fixed at the switching chamber. For example, the upper yoke element may be fixed inside the switching chamber, preferably by welding or adhesive bonding. Alternatively, the upper yoke element can also be fastened to the switching chamber by riveting or screwing. Furthermore, the upper yoke element can be held inside the switching chamber, for example, by means of a fastening element, for example made of plastic. In this case, the upper yoke element can be fixed in the switching chamber, for example, by caulking (Versteemen). In this case, the upper yoke element can be inserted, for example, loosely into the switching chamber or a part of the switching chamber and, during assembly, is locked in the switching chamber, particularly preferably in a form-fitting manner, by clamping or caulking. Since the upper yoke element is not part of the contact means, this can advantageously be achieved in comparison with the prior art described above: the upper yoke element does not move together during the switching movement of the contact means. The upper yoke element can thus be embodied, for example, in a larger size than the yoke elements usual in the prior art, since the mass of the upper yoke element is not important for the switching movement.

According to a further embodiment, the lower yoke element is arranged displaceably at the holding element. In one aspect, the position of the lower yoke element relative to the upper yoke element can be correspondingly changed by a movement of the lower yoke element in the contact device. The air gap between the lower yoke element and the upper yoke element can thereby also be varied in particular in the on state of the switching device. On the other hand, in the preferred case of the upper yoke element being fixed at the switching chamber, the position of the lower yoke element relative to the upper yoke element can be changed by a movement of the contact device in the switching chamber. Particularly preferably, the lower yoke element is arranged at the holding element in a displaceable manner in a direction parallel to the axis.

According to a further embodiment, the contact bridge is arranged at the holding element. The contact bridge can be arranged in a displaceable manner in particular at the holding element. Particularly preferably, the contact bridge can be arranged at the holding element in a displaceable manner in a direction parallel to the axis.

The term "element, i.e. in particular the lower yoke element and/or the contact bridge, is arranged displaceably on the holding element" may particularly mean: the mentioned element can be moved relative to the holding element in preferably only one direction, which may also be referred to as the direction of movement, and is at the same time limited in terms of its freedom of movement by the holding element. A limitation of the degree of freedom of movement may exist along the direction of movement such that displaceability along the direction of movement is limited to a certain distance. Preferably, the freedom of movement in directions other than this direction of movement is at least significantly limited, except for tolerances.

Particularly preferably, in the case of the presence of the lower yoke element, the contact bridge, the lower yoke element and the upper yoke element are each arranged in such a way that they can be moved in pairs relative to one another. This means: the contact bridge and the lower yoke element are arranged in a movable manner relative to each other, since the contact bridge and/or the lower yoke element are arranged in a movable manner at the holding element. Furthermore, the contact bridge and the lower yoke element (if present) are arranged in a movable manner with respect to the upper yoke element, which can be achieved, for example, in the following manner: the contact bridge and the lower yoke element, if present, are part of a movable contact means, whereas the upper yoke element is not part of this contact means.

For example, the holding element may have at least one guide element for guiding the contact bridge and/or the lower yoke element. The at least one guide element may be formed, for example, by a guide rail, and in particular a guide in a direction parallel to the axis and thereby a direction of movement in a direction parallel to the axis may be achieved. Particularly preferably, the holding element has a plurality of guide elements. Preferably, a limitation of the mobility in directions other than the desired direction of movement can also be achieved by the guiding element. Furthermore, the holding element may have at least one stop for limiting the displaceability of the contact bridge and/or the lower yoke element. The at least one stop may in particular cause a restriction along the direction of movement and thereby preferably along a direction parallel to the axis. Particularly preferably, the holding element can have a plurality of stops.

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

According to a further embodiment, the contact bridge is arranged between the base of the holding element and the upper yoke element. In the case of the presence of a lower yoke element, the contact bridge is arranged between the lower yoke element and the upper yoke element. In particular, the upper yoke element may be arranged above the contact device, as seen from the shaft. The contact bridge may have an upper side and a lower side opposite the upper side, wherein the lower yoke element (if present) is arranged below and thereby on the lower side of the contact bridge, and the upper yoke element is arranged above and thereby on the upper side of the contact bridge.

According to a further embodiment, the upper yoke element has a recess on the underside facing the contact bridge. The recess can be designed in particular as a groove-like or channel-like recess. In the on-state of the switching device, the contact bridge can extend partially into the recess. The recess may in particular have a width which is greater than the width of the contact bridge, at least in the region of the recess. For example, the contact bridge may have a constriction, i.e. a region of reduced width, wherein in the on state of the switching device the constriction is arranged at least partially in the recess of the upper yoke element. Furthermore, the recess may have a depth which is equal to or substantially equal to the thickness of the contact bridge, at least in the region of the recess. In addition, the contact bridge may have a thickness greater than the depth of the recess. The contact bridge can be accommodated in the recess when the switching device is switched from the off-state to the on-state by a switching movement of the contact device. The upper yoke element may thus at least partially surround the contact bridge in the on-state. Preferably, in the on-state of the switching device, the contact bridge can protrude partially from the recess.

Furthermore, the contact bridge can also be spaced apart from the upper yoke element in the on-state. In other words, the contact bridge is therefore not in mechanical contact with the upper yoke element in the on state. Correspondingly, even in the on-state, an air gap between the upper yoke element and the contact bridge can be maintained.

According to a further embodiment, the holding element has an electrically insulating material. Particularly preferably, the holding element is made of one or more electrically insulating materials, so that the holding element can be electrically insulating. The one or more electrically insulating materials may be selected from polymeric and ceramic materials, for example from Polyoxymethylene (POM), in particular with (CH) ₂ O) _n Structural polyoxymethylene, polybutylene terephthalate (PBT), glass-fiber-filled PBT and electrically insulating metal oxides, such as Al ₂ O ₃ . In particular, the holding element may electrically insulate the contact bridge or preferably the contact bridge and the contact spring as well as the lower yoke element from the shaft. The contact bridge can thereby be arranged in an electrically insulated manner from the components of the magnetic drive, i.e. in particular from the other components of the armature. The holding element can thereby simultaneously effect the placement of the contact bridge and the electrical insulation of the contact bridge.

For example, the upper yoke element may be arranged laterally beside the at least one fixed contact. Here and hereinafter, "lateral" refers to a direction perpendicular to the axis of the armature. Particularly preferably, the switching device has two fixed contacts, and the upper yoke element is arranged between the two fixed contacts.

It may also be possible that: the holding element has a portion, such as the stop described above, which, in the on-state of the switching device, protrudes into the intermediate space between the at least one fixed contact and the upper yoke element. Thereby, for example, an electrical insulation of the upper yoke element from the at least one fixed contact can be achieved. Preferably, in the case of two fixed contacts between which the upper yoke element is arranged, the holding element can correspondingly have two parts, for example two stops, wherein in the on state of the switching device each of these stops can protrude into the intermediate space between the fixed contact and the upper yoke element.

According to a further embodiment, the contact device also has a spring, which may also be referred to as a contact spring in the following, and which is arranged on the underside of the contact bridge facing away from the upper yoke element. Thus, if the contact device also has a lower yoke element, the contact spring is arranged at the underside of the contact bridge facing the lower yoke element. The contact spring may particularly preferably press the contact bridge in the direction of the at least one fixed contact. During the switching process of the switching device from the off-state to the on-state, the armature and thereby the shaft and the contact device are preferably moved in a linear movement in the form of a lifting or lowering movement along the shaft, which may also be referred to as a vertical direction. Preferably, the shaft and, for example, the magnetic core of the armature have a movement space in the vertical direction for the lifting movement, which is greater than the switching gap, which is formed in the non-conductive state by the distance between the at least one fixed contact and the contact bridge. This can be achieved, for example, by: in the off-state, the gap, which may also be referred to as the movement gap, between the core and the yoke of the magnetic circuit is greater than the switching gap. When the contact bridge contacts the at least one fixed contact and thereby the switching gap is fully closed, the contact spring can be compressed and the armature can continue to move until, for example, the magnetic core rests against the magnet yoke. The armature with the contact device can thus be an over-travel lifting system, in which the contact bridge is arranged displaceably at the holding element. For example, the movement gap may be less than or equal to 1mm, and particularly preferably about 0.5mm greater than the switching gap. By the compression of the contact spring due to the over-travel lift, the contact pressure of the contact bridge at the at least one fixed contact can be increased and a certain insensitivity to vibrations and mechanical shocks can be achieved.

According to a further embodiment, the contact spring is arranged between the contact bridge and the base of the holding element or, in the case of the presence of the lower yoke element, between the contact bridge and the lower yoke element, such that the contact spring is intended to push the contact bridge and the base or the contact bridge and the lower yoke element away from each other. The contact spring thus generates, in particular, a spring force which counteracts the approach of the lower yoke element to the base or to the contact bridge. The spring may preferably be supported directly on the underside of the contact bridge and on the base or on the lower yoke element. In the second case, the lower yoke element may have a recess into which the spring protrudes, and which may fix the position of the contact spring. In the case of a switching device without a lower yoke element, the holding element, in particular the base, can have a spring retainer which counteracts a displacement of the contact spring at the holding element. For example, the spring retainer may have or be formed of a peg surrounded by a portion of the contact spring.

In the on state of the switching device, a magnetic field is induced in the upper yoke element when a current flows through the contact bridge. In this case, the magnetic field lines can be concentrated on the upper side of the upper yoke element, in particular in the case of high currents, such as short-circuit currents, which pass through the contact bridge. Since this magnetic field seeks a shortest path to minimize energy, it is strongly compressed towards the underside of the contact bridge and through the contact bridge and generates a detent force on the contact bridge, which counteracts the levitation force and can correspondingly also be referred to as anti-levitation force. Thus, a holding effect can be achieved by the flux of the magnetic field from the upper yoke element through the contact bridge.

In the case of a switching device having a lower yoke element, the contact bridge is particularly preferably arranged between the upper yoke element and the lower yoke element as described above. In addition to the above-described effects of the upper yoke element on the contact bridge, these yoke elements can also absorb in this case the magnetic field that is formed when a current flows through the contact bridge. This means: in this case, the two yoke elements are magnetized by a magnetic field formed by a contact bridge through which an electric current flows, so that an attractive force is formed between the two yoke elements. Since the upper yoke element is arranged above the contact bridge at the holding element and the lower yoke element is arranged below the contact bridge, the lower yoke element can be pulled upwards, i.e. in the direction of the upper yoke element, by the attractive force formed between these yoke elements. This effect can enhance the above-described holding effect. By means of the contact spring, the lower yoke element can exert a force on the contact bridge, so that the contact bridge is additionally pressed upwards and thereby in the direction of the at least one fixed contact. The greater the current flowing through the contact bridge, the stronger the attractive force acting between these yoke elements. However, since the contact spring is intended to push the lower yoke element away from the contact bridge and thereby also from the upper yoke element, and the lower yoke element is movably arranged at the holding element, the spring force may be greater than the attractive force between these yoke elements in case the current through the contact bridge is sufficiently small. Only if the attractive force between the yoke elements exceeds the spring force of the contact spring, the upper yoke element can be moved in the direction of the upper yoke element and thereby the contact bridge is pressed more strongly against the at least one fixed contact by means of the now more strongly compressed contact spring. This makes it possible to counteract the above-described floating effect in a reinforced manner, in particular in the case of short-circuit currents.

Thus, as described, in the on state of the switching device, a current can flow through the contact bridge, which generates a magnetic flux that causes an attractive force between the contact bridge and the upper yoke element and, if present, between the lower yoke element and the upper yoke element. If the contact device has a lower yoke element, the contact device and the upper yoke element are designed such that: in the case that the current is less than the current threshold, the lower yoke element is arranged at a first distance from the upper yoke element; and the lower yoke element is arranged at a second distance from the upper yoke element, where the second distance is smaller than the first distance, in case the current is larger than the current threshold. The first distance and the second distance may for example correspond to respective dimensions of the air gap, whereby the air gap becomes smaller when the current threshold is exceeded. Correspondingly, the air gap between the lower yoke element and the upper yoke element during operation of the switching device is dependent on the current flowing through the contact bridge.

Below the current threshold, the air gap and thereby the first distance may be greater than 1mm, for example up to 3mm or even up to 5mm, and thereby may be much greater than the above-described prior art in which the air gap is also substantially unchanged. After the current threshold is exceeded, the air gap and thereby the second distance may be less than 1mm and particularly preferably equal to 0 or at least approximately 0. In other words, after the current threshold is exceeded, with a suitable geometric design of the contact device and the upper yoke element, it may preferably be possible to: the lower yoke element is pulled towards the upper yoke element to such an extent that the lower yoke element rests against the upper yoke element or that an air gap of less than 1mm is at least present.

The current threshold may be adjusted by a suitable choice of the spring constant of the contact spring and the geometrical design and dimensions of the yoke elements and the first distance. The current threshold can in particular be adjusted such that the current corresponding to the normal operation of the switching device is below the current threshold. Thereby, it is possible to realize: in normal operation and also for small short-circuit currents, for example, the attractive force between the yoke elements is small due to the large air gap with the first distance, so that no increased contact force is produced between the contact bridge and the at least one fixed contact, and the contact bridge is held at the at least one fixed contact only by the contact spring. Only when the higher short-circuit current exceeds the current threshold, the lower yoke element moves towards the upper yoke element, so that a stronger levitation force can be compensated by the attractive forces of these yoke elements. As described, the air gap is thus variably embodied as a function of the current flowing through the contact bridge, whereby the holding force likewise becomes variable. The method can be realized as follows: the additional holding force caused by the lower yoke element is only "on" by these yoke elements in the event of a short circuit, in that the lower yoke element closes the magnetic circuit with the upper yoke element.

Since in the switching device described here the upper yoke element is preferably firmly fixed directly at the switching chamber, it is no longer dependent on the holding force of the magnetic drive of the switching device and thus no longer depends on the holding force of the coil as is the case in the prior art described above. The upper yoke element of the switching device described here can thus absorb large forces, in particular forces of more than 500N. On the other hand, in prior art solutions, the forces caused by the yoke element are typically limited to about 100N, since these forces can only be as great as the holding force of the magnetic drive coil. Thus, in the switching device described here, a significantly larger short-circuit current can be achieved. Although it has been shown that: the solutions known in the prior art are generally only suitable for short-circuit currents of up to 8kA during a period of 5ms, but experiments performed using the switching device described herein have shown that: short-circuit currents of up to 16kA can be achieved.

In contrast to the complex structures of the prior art, the anti-levitation effect described here can be realized essentially using only one additional component, namely the upper yoke element. As described above, an increase in this anti-levitation effect can be achieved using the lower yoke element, and thus the upper yoke element and the lower yoke element, which can be additionally provided, and which can also be switched on in a targeted manner. Furthermore, by the arrangement of the upper yoke element at the switching chamber, whether or not the lower yoke element is present, it is possible to realize: the upper yoke element does not move together during switching. Thereby, the dynamic mass is reduced, facilitating a faster switching process.

Drawings

Further advantages, advantageous embodiments and developments emerge from the examples described below with reference to the figures.

Fig. 1 shows a schematic diagram of an example of a switching device;

fig. 2A to 2F show schematic diagrams of fragments and parts of a switching device according to an embodiment;

fig. 3 shows a schematic view of the effect of the upper yoke element on the contact bridge;

FIGS. 4A and 4B show schematic views of portions of a switching device according to other embodiments;

fig. 5A to 5D show schematic diagrams of fragments and parts of a switching device according to an embodiment; and

fig. 6A to 6D show schematic diagrams of fragments of a switching device according to other embodiments.

Detailed Description

In the examples and figures, identical, similar or functionally equivalent elements may be provided with the same reference numerals, respectively. The elements shown and their dimensional relationships to one another are not to scale, rather, individual elements, such as layers, components, devices and regions, may be exaggerated for better presentation and/or for better understanding.

An example of a switching device 100 is shown in fig. 1, which may be used, for example, for switching high currents and/or high voltages, and which may be a relay or a contactor, in particular a power contactor. In fig. 1 a three-dimensional cross-section with a vertical cross-section is shown. The illustrated geometry should be understood as exemplary only and not limiting, and may be designed in alternative ways.

The switching device 100 has contacts 1, which are also referred to as switching contacts in the following, in a housing (not shown). The housing serves mainly as contact protection for the components arranged inside and has or is made of plastic, for example PBT or glass-fibre-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, which is arranged on an insulator 3, as contacts 1. The contact bridge 4 is designed as a contact plate. These fixed contacts 2 form, together with the contact bridge 4, switch contacts. Instead of the shown number of contacts, other numbers of contacts 1, 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 be made of, for example, the following materials or of the following materials: cu, cu alloys, one or more refractory metals such as Wo, ni and/or Cr, or mixtures of the mentioned materials, e.g. copper with at least one further metal, e.g. Wo, ni and/or Cr.

In fig. 1, the switching device 100 is shown in an off-state in which the contact bridge 4 is spaced apart from the fixed contact 2 such that the contacts 2, 4 are galvanically isolated from each other. The illustrated embodiment of the switch contacts and in particular of the geometry thereof should be understood as purely exemplary and not limiting. Alternatively, the switch contacts can also be designed in other ways.

The switching device 100 has a movable armature 5 which essentially performs a switching movement. The armature 5 has a core 6, which is made of ferromagnetic material or is made of ferromagnetic material, for example. The armature 5 furthermore has a shaft 7 which is guided through the magnetic core 6 and is firmly connected to the magnetic core 6 at one axial end. At the other axial end, opposite the core 6, the armature 5 has a contact bridge 4. Preferably, the shaft 7 may be manufactured using or from stainless steel.

For the electrical insulation of the contact bridge 4 from the shaft 7, an insulator 3, which may also be referred to as bridge insulator, is arranged between the contact bridge and the shaft. In order to support the compensation of possible height differences and to ensure a sufficient mechanical contact between the fixed contact 2 and the contact bridge 4, a contact spring 34 is arranged below the contact bridge 4, which contact spring is supported at the insulator 3 and exerts a force on the contact bridge 4 in the direction of the fixed contact 2.

The magnetic core 6 is surrounded by a coil 8. The passage of current in the coil 8, which can be switched on from the outside by the control circuit, produces a displacement of the magnet core 6 and thus of the entire armature 5 in the axial direction until the contact bridge 4 is brought into contact with the fixed contact 2. In the illustration shown, the armature is moved upward for this purpose. The armature 5 is thus moved from a first position, i.e. a rest position corresponding to a separated, i.e. non-conductive, and thus off-state, to a second position corresponding to an activated, i.e. conductive, and thus on-state. In the active state, the contacts 1 are galvanically connected to one another.

In order to guide the shaft 7 and thereby the armature 5, the switching device 100 has a magnet yoke 9, which may have or may be made of pure iron or a low-doped iron alloy and which forms part of a magnetic circuit. The yoke 9 has an opening in which the shaft 7 is guided. If the passage of current in the coil 8 is interrupted, the armature 5 is moved back into the first position by means of one or more springs 10. In the illustration shown, the armature 5 is thus moved again downwards. The switching device 100 is then brought back to a rest state in which the contact 1 is opened.

The direction of movement of the armature 5 and thus of the contact bridge 4 is also referred to below as the vertical direction 91. The arrangement direction of the fixed contacts 2 perpendicular to the vertical direction 91 is hereinafter referred to as the longitudinal direction 92. The direction perpendicular to the vertical direction 91 and perpendicular to the longitudinal direction 92 is hereinafter referred to as the transverse direction 93. In some of the figures, directions 91, 92 and 93 are sketched, which are also applicable independently of the described switching movement, for ease of orientation. The direction parallel to the plane extending through the longitudinal direction 92 and the transverse direction 93 and thereby perpendicular to the vertical direction 91 is also referred to as the lateral direction 90.

For example, when the contact 1 opens, at least one arc may form, which may damage the contact surface of the contact 1. Thus, there may be the following risks: the contacts 1 remain "stuck" to each other and no longer separated from each other due to the welding caused by the arc. Therefore, even if the current in the coil 8 is switched off and the load circuit must therefore be separated, the switching device 100 then continues to be in the on state. In order to prevent the formation of such an arc or at least to support the extinguishing of an occurring arc, the contact 1 may be arranged in a gas atmosphere, so that the switching device 100 may be designed as an air-filled relay or an air-filled contactor. In particular, the contact 1 is arranged in a gas-tight region 14 formed by a hermetically closed part within the switching chamber 11, which is formed, for example, by the switching chamber wall 12 and the switching chamber bottom 13, wherein the switching chamber 11 can be part of the gas-tight region 14. The airtight region 14 completely encloses the armature 5 and the contact 1, except for the portion of the fixed contact 2 that is provided for external connection. The airtight region 14 and thereby also the interior space 15 of the switching chamber 11 are filled with gas. The airtight area 14 is basically formed by the switch chamber 11, the yoke 9 and portions of the additional wall. The gas that can be filled into the gas-tight region 14 within the production frame of the switching device 100 via the gas filling neck can particularly preferably contain hydrogen, for example with 20% or more H in an inert gas ₂ Or even have 100% H ₂ Because of the hydrogen-containing gasThe body may facilitate extinguishing of the arc. Furthermore, so-called blow-out magnets, i.e. permanent magnets 16, may be present inside or outside the switching chamber 11, which may cause an extension of the arc path and thus improve the extinguishing of the arc.

For example, al may be used for the switching chamber wall 12 and the switching chamber bottom 13 ₂ O ₃ Such metal oxides are produced or made of, for example, al ₂ O ₃ Such metal oxides are produced. In addition, plastics with sufficiently high temperature resistance, such as PEEK, PE and/or glass-fiber-filled PBT, are also suitable. Alternatively or additionally, the switching chamber 11 may also have a POM, in particular a (CH ₂ O) _n Structure is as follows. Such plastics may be distinguished by a relatively low carbon content and a very low tendency to form graphite. Since the catalyst is especially used in (CH ₂ O) _n In the case of decomposition initiated by heat and in particular by electric arcs, the carbon and oxygen ratios are the same, gaseous CO and H are mainly formed ₂ . Additional hydrogen may enhance arc extinction.

The above-described features of the switching device 100 should be understood to be purely exemplary and not limiting. For example, instead of the embodiment described as an inflation contactor, the switching device 100 may also be implemented without a filling gas. The above description of the example of fig. 1 is used in particular to clarify the working principle of the switching device.

In the following, an embodiment of a switching device 100 is shown, which in comparison to the switching device of fig. 1 has a contact device 200 and an upper yoke element 50 or a lower yoke element 40 and an upper yoke element 50, which yoke element or these yoke elements form an anti-levitation mechanism.

In fig. 2A to 2F, different segments and parts of a switching device 100 according to an embodiment are shown. Fig. 2A shows a three-dimensional cross-sectional view of a part of the switching device 100 with the contact device 200, while fig. 2B to 2F show different views of the switching device 100 and in particular of the part of the contact device 200. The following description of the switching device 100 also refers to all fig. 2A to 2F. The elements shown in fig. 2A to 2F correspond to the elements set forth in connection with fig. 1, unless otherwise indicated.

In fig. 2A, the housing 19 of the switching device 100 is additionally shown in comparison to the view of fig. 1. The contact device 200 is arranged in the switching chamber 11, has the contact bridge 4 and the holding element 30 and is fastened to the shaft 7. Thereby, the contact device 200 may be moved by the above-described magnetic force driver to perform the switching movement of the switching device 100.

The switching device 100 also has an upper yoke element 50. The upper yoke element 50 may have or be made of iron. The upper yoke element 50 may in particular have or be made of pure iron. The contact bridge 4 is arranged below the upper yoke element 50 by means of the holding element 30.

The upper yoke element 50 is not part of the contact device 200, but is arranged in the switching chamber 11 independently of the contact device 200 and thereby independently of the lower yoke element 40. In particular, the upper yoke element 50 is arranged with respect to the fixed contacts 2 and is fixed between these fixed contacts. As can be seen in fig. 2A, the upper yoke element 50 and the fixed contact 2 are preferably fastened to the switching chamber 11, in particular the switching chamber wall 12, which may be made of ceramic material, for example, in order to be able to achieve sufficient stability. For example, the upper yoke element 50 and the fixed contact 2 may be fixed at the switching chamber by welding, respectively. For this purpose, the upper yoke element 50 may have a welded flange. The upper yoke element 50 can be fixed inside the switching chamber 11, in particular by welding. Alternatively, the upper yoke element 50 can also be fixed to the switching chamber 11 by means of adhesive bonding, riveting or screwing or caulking.

The holding element 30 is fixed to the shaft 7. In the embodiment shown, the holding element 30 has an electrically insulating plastic, in particular the plastic described above in the general section, wherein a portion of the shaft 7 is formed with the material of the holding element 30, as can be seen in fig. 2A. For locking the holding element 30 and thereby the contact device 200, the shaft 7 has anchoring elements in the form of grooves which run completely around the shaft 7 and into which the material of the holding element 30 can engage. Alternatively, other fastening methods are also possible, for example by means of riveting or screwing.

The holding element 30 has a base 31 which is fixed to the shaft 7. As is outlined in fig. 2B and 2C, at the base 31 the holding element 30 has a clamping element 32 for movably mounting the contact bridge 4. Particularly preferably, the holding element 30 can be designed in an integrated manner and has the materials described above in the general section. The contact bridge 4 is arranged displaceably by means of a clamping element 32 at the holding element 30. In particular, the contact bridge 4 is arranged at the holding element in a displaceable manner along a direction of movement parallel to the axis 7. For guiding the contact bridge 4, the holding element 30 has a guide element 36 and a stop 37, which form the clamping element 32. The guide element 36 is embodied as a guide rail and enables a movement of the contact bridge 4 in the desired displacement direction, while the movability of the contact bridge 4 in the other direction is limited by the guide element 36. In order to limit the displaceability of the contact bridge 4, in particular along the axis 7, in the displacement direction, the holding element 30 has stops 37 which are arranged on the side of the guide element 36 opposite the base 31. In particular, two guide elements and one stop 37 each form a clamping element 32, which forms an opening 38 with the base 31, respectively. As shown in fig. 2B, each of these clamping elements 32 surrounds the contact bridge 4. In other words, the contact bridge 4 can protrude through the opening 38 and can thus be guided in the opening 38 of the clamping element 32.

The holding element 30 can also be designed such that: in the on state of the switching device 100, the stops 37 each protrude into the intermediate space between the fixed contact 2 and the upper yoke element 50, as can be seen in fig. 2A. Thereby, for example, an electrical insulation of the upper yoke element 50 from at least part of the at least one fixed contact 2 can be achieved.

The contact device 200 also has a contact spring 34, which is arranged on the underside of the contact bridge 4 facing the base 31. In other words, the contact spring 34 is arranged between the contact bridge 4 and the base 31. The holding element 30 and in particular the base 31 of the holding element 30 have a spring holder 39 which counteracts the displacement of the contact spring 34 at the holding element 30. As shown, the spring holder 39 may, for example, have a peg or be formed by a peg, which is surrounded by a portion of the contact spring 34.

The contact spring 34 is embodied as a compression spring. As described above, by the contact spring 34, in combination with the over-travel lift, the contact pressure of the contact bridge 4 to the fixed contact 2 can be increased. Since the contact spring 34 is arranged between the contact bridge 4 and the base 31, the contact spring 34 is intended to push the contact bridge 4 and the base 31 away from each other, whereby the contact bridge 4 is pressed in the direction of the fixed contact 2.

The upper yoke element 50 has a recess 52 on the underside facing the contact bridge 4. As can be seen in fig. 2A, 2E and 2F, the recess 52 can in particular be designed as a groove-like or channel-like recess. In the on-state of the switching device 100, the contact bridge 4 can extend at least partially into the recess 52. Furthermore, as can be seen, for example, in fig. 2D, in a view of the underside of the contact bridge 4 and of the underside of the upper yoke element 50, the contact bridge 4 can have a constriction 45, i.e. a web-shaped region of reduced width compared to the contact region of the contact bridge 4, wherein the constriction 45 is arranged at least partially in the recess 52 of the upper yoke element 50 in the on-state of the switching device 100. In particular, the recess 52 has a width which is greater than the width of the contact region 4 at least in the region of the constriction 45. Further, the recess 52 may have a depth that is less than or equal to or substantially equal to the thickness of the contact bridge 4. The contact bridge 4 can be received in this recess 52 when the switching device 100 is switched from the off-state to the on-state by the switching movement of the contact device 200. In the on-state of the switching device 100, the upper yoke element 50 can therefore at least partially surround the contact bridge 4 in the lateral direction 90, in particular in the transverse direction 93. In fig. 2D, the position of the contact spring 34 is also sketched.

It is particularly preferred that the contact bridge 4 has a thickness which may be greater than the depth of the recess 52, as can be seen in particular in fig. 2E. The upper yoke element 50 can therefore only partially surround the contact bridge 4 in the on state. Thus, in the on-state of the switching device 100, the contact bridge may partially protrude from the recess 52.

Furthermore, it is particularly preferred that the contact bridge 4 can be spaced apart from the upper yoke element 50 in this on state. As can also be seen in fig. 2E, it is thus possible that: in this on state, the contact bridge is not in mechanical contact with the upper yoke element 50. Correspondingly, even in the on state, an air gap between the upper yoke element 50 and the contact bridge 4 can be maintained. By providing such a gap, manufacturing tolerances may be taken into account, for example. It is also possible to realize: the possible burning, i.e. the removal and uncontrolled deposition of material of the contact 1, which may occur, for example, when a switching arc is formed, does not have undesirable consequences.

The upper yoke element 50 forms together with the contact bridge 4 an anti-levitation mechanism whose principle of operation is outlined in connection with fig. 3 in terms of a fragment of the switching device 100 in a sectional view with a cross section along a vertical direction 91 and a lateral direction 92. In this case, the switching device 100 is shown in an on state, in which a current I flows through the contact bridge 4. In particular in the case of short-circuit currents, as described above in the general section, a levitation force Flev may occur which pushes the contact bridge 4 away from the fixed contacts. The levitation force only resists the spring force of the contact spring without the following effect.

As is schematically shown in fig. 3, in the switching device described here, in the on state of the switching device, a magnetic field having a magnetic flux MF is induced in the upper yoke element 50 when a current flows through the contact bridge 4. In this case, the magnetic field lines can be concentrated on the upper side of the upper yoke element 50, in particular in the case of high currents, such as short-circuit currents, which pass through the contact bridge 4. Here, a large thickness of the upper yoke element 50 above the contact bridge 4 may be advantageous. In particular, the upper yoke element 50 may particularly preferably have a greater thickness above the contact bridge 4 in the vertical direction 91 than the contact bridge 4.

Since this magnetic field seeks a shortest path to minimize energy, it is strongly compressed towards the underside of the contact bridge 4 and through the contact bridge 4 and generates a detent force Frel on the contact bridge 4, which counteracts the levitation force and can correspondingly also be referred to as counter-levitation force. Thus, a holding effect can be achieved by the flux of the magnetic field from the upper yoke element 50 through the contact bridge 4.

Modifications and extensions of the switching device are described in connection with the following figures.

As outlined in fig. 4A, the contact bridge 4 can also be designed without constrictions and can therefore have a simple cuboid shape, for example. Furthermore, as outlined in fig. 4B, it may also be possible to: one or more or all edges of the upper yoke element 50 and/or the contact bridge 4 are rounded or beveled.

Another embodiment of the switching device 100 is illustrated in conjunction with the subsequently described figures. In fig. 5A to 5D, different segments and parts of a switching device 100 according to another embodiment are shown. Fig. 5A shows a sectional view of a switching device 100 with a contact device 200, while fig. 5B to 5D show different views of the switching device 100 and in particular of parts of the contact device 200. The following description of the switching device 100 also refers to all fig. 5A to 5D.

In fig. 5A, the housing 19 of the switching device 100 is additionally shown in comparison with the view of fig. 1, while the return spring 10 for resetting the magnetic drive 5 to this off state is not shown for the sake of clarity in comparison with fig. 1. In fig. 5B, the coil connection 18 for the steering coil 8 is also shown. The elements shown in fig. 5A to 5D correspond to the elements set forth in connection with fig. 1 and in connection with fig. 2A to 3, unless otherwise indicated.

The contact device 200 is arranged in the switching chamber 11, has the contact bridge 4, the holding element 30 and the lower yoke element 40 and is fastened to the shaft 7. Thereby, the contact device 200 may be moved by the above-described magnetic force driver to perform the switching movement of the switching device 100.

As in the embodiment of fig. 2A to 2F, the switching device 100 also has an upper yoke element 50. The lower yoke element 40 and the upper yoke element 50 may have iron or be made of iron, respectively. These yoke elements 40, 50 may in particular each have or be made of pure iron. The contact bridge 4 is arranged between the lower yoke element 40 and the upper yoke element 50.

As described in connection with fig. 2A to 2F, the upper yoke element 50 is not part of the contact device 200, but is arranged and fixed in the switching chamber 11 independently of the contact device 200 and thereby independently of the lower yoke element 40, as described in connection with fig. 2A to 2F.

The holding element 30 is fixed to the shaft 7. In the embodiment shown, the holding element 30 has an electrically insulating plastic, in particular the plastic described above in the general section, wherein a part of the shaft 7 is formed with the material of the holding element 30. In order to lock the holding element 30 and thereby the contact device 200, as can be seen in fig. 5A, the shaft 7 has an anchoring element in the form of a groove which runs completely around the shaft 7 and into which the material of the holding element 30 can engage. Alternatively, other fastening methods are also possible, for example by means of riveting or screwing.

The holding element 30 has a base 31 which is fixed to the shaft 7. At the base 31, the holding element 30 has a clamping element 32 for the movable arrangement of the contact bridge 4 and the lower yoke element 40. Particularly preferably, the holding element 30 can be designed in an integrated manner and has the materials described above in the general section.

The contact bridge 4 and the lower yoke element 40 are each arranged displaceably at the holding element 30. Correspondingly, the position of the lower yoke element 40 relative to the upper yoke element 50 may vary depending on the state of the switching device 100. On the one hand, the relative position of the lower yoke element 40 with respect to the upper yoke element 50 can be changed by a displacement of the lower yoke element 40 at the holding element 30 and thereby in the contact device 200. Thereby, as will be described in more detail below, the air gap between the lower yoke element 40 and the upper yoke element 50 may in particular be changeable in the on-state of the switching device 100. Furthermore, the position of the lower yoke element 40 relative to the upper yoke element 50 can be changed by a movement of the contact device 200 in the switching chamber 11. Particularly preferably, the lower yoke element 40 is arranged on the holding element 30 such that the lower yoke element 40 can be displaced in a displacement direction which runs parallel to the axis 7 and thus in the vertical direction 91. Furthermore, the contact bridge 4 is also arranged at the holding element in a displaceable manner in a direction of movement parallel to the axis 7. Thereby, the contact bridge 7 and the lower yoke element 40 as well as the contact bridge 7 and the upper yoke element 50 may also be displaceable relative to each other.

The lower yoke element 40 can be placed on the base 31 at least in the off-state of the switching device 100, which is illustrated in fig. 5A to 5C. For reliable positioning, the lower yoke element 40 can have, for example, edge-side guide grooves on the side facing the base 31, into which the projections of the base 30 can engage.

For guiding the contact bridge 4 and the lower yoke element 40, the holding element 30 has a guide element 36 and a stop 37. The guide element 36 is embodied as a guide rail and enables a movement of the contact bridge 4 and the lower yoke element 40 in the desired displacement direction, while the movability of the contact bridge 4 and the lower yoke element 40 in the other direction is limited by the guide element 36. In order to limit the displaceability of the contact bridge 4 and the lower yoke element 40, in particular along the axis 7, in the displacement direction, the holding element 30 has stops 37 which are arranged on the side of the guide element 36 opposite the base 31. In particular, two guide elements and one stop 37 each form a clamping element 32, which forms an opening 38 with the base 31, respectively. As shown in fig. 5C, each of these clamping elements 32 surrounds the contact bridge 4. In other words, the contact bridge 4 can protrude through the opening 38 and can thus be guided in the opening 38 of the clamping element 32. In the embodiment shown, the lower yoke element 40 is guided between the clamping elements 32. Alternatively or additionally, however, the lower yoke element 40 may also be designed such that: the lower yoke element protrudes through the opening 38 and is guided in the opening 38 and is thus surrounded by the clamping element 32.

The holding element 30 can also be designed such that: in the on state of the switching device 100, the stops 37 each protrude into the intermediate space between the fixed contact 2 and the upper yoke element 50, as can be seen in fig. 5B. Thereby, for example, an electrical insulation of the upper yoke element 50 from at least part of the at least one fixed contact 2 can be achieved.

The contact device 200 also has a contact spring 34, which is arranged on the underside of the contact bridge 4 facing the lower yoke element 40. In other words, in contrast to the embodiment of fig. 2A to 2F, the contact spring 34 is arranged between the contact bridge 4 and the lower yoke element 40. The contact spring 34 is embodied as a compression spring. As described above, by the contact spring 34, in combination with the over-travel lift, the contact pressure of the contact bridge 4 to the fixed contact 2 can be increased. Since the contact spring 34 is arranged between the contact bridge 4 and the lower yoke element 40, the contact spring 40 is intended to push the contact bridge 4 and the lower yoke element 40 away from each other. The contact spring 34 thus generates a spring force which counteracts the approach of the lower yoke element 40 to the contact bridge 4. As shown, the contact spring 34 can be supported in particular directly on the underside of the contact bridge 4 and/or directly on the lower yoke element 40. The lower yoke element 40 has a recess 41 into which the contact spring 34 protrudes, and by means of which the position of the contact spring 34 can be fixed.

The upper yoke element 50 has a recess 52 on the underside facing the contact bridge 4. As shown, the recess 52 can in particular be designed as a groove-like or channel-like recess. In the on-state of the switching device 100, the contact bridge 4 can extend at least partially into the recess 52. Furthermore, as can be seen, for example, in the view of fig. 5D on the underside of the contact bridge 4 and on the underside of the upper yoke element 50, as already explained in connection with the exemplary embodiments of fig. 2A to 2F, the contact bridge 4 can have a constriction 45, i.e. a web-shaped region of reduced width compared to the contact region of the contact bridge 4, wherein the constriction 45 is arranged at least partially in the recess 52 of the upper yoke element 50 in the on-state of the switching device 100. In particular, the geometrical design of the contact bridge 4 and the upper yoke element 50 may be as described in connection with fig. 2A to 4B.

Instead of or in addition to the illustrated embodiment, the lower yoke element 40, which is designed, for example, in the illustrated embodiment as a plate, can also have recesses corresponding to the recesses 52, while the upper yoke element 50 can have a flat underside. Furthermore, it may also be possible that: the two yoke elements 40, 50 each have a recess, by means of which each of these yoke elements 40, 50 can partially surround the contact bridge 4 from below or from above at a corresponding position relative to the contact bridge 4.

In addition to the effects described in connection with fig. 3, the contact device 200 and in particular the lower yoke element 40 and the upper yoke element 50 form a further anti-levitation mechanism whose principle of operation is elucidated in connection with fig. 6A to 6D on the basis of the fragments of the switching device 100 in a sectional view with sections along the vertical direction 91 and the longitudinal direction 93 (fig. 6A, 6C), along the vertical direction 91 and the transverse direction 92 (fig. 6B, 6D). In this case, the switching device 100 is shown in an on state in which a current I flows through the contact bridge 4, as is outlined in fig. 6A and 6C.

In the off state of the switching device 100, the movable portion of the switching device 100 is disposed in a lower rest position, such as previously shown in fig. 5A. In this state, the electrical contact between the fixed contact 2 and the contact bridge 4 is separated. The contact spring 34 biases the contact bridge 4 and the lower yoke element 40 and holds them in place in the cage of the holding element 30 formed by the base 31 and the clamping element 32. When the switching device 100 is turned on, a control current flows through the coil 8 of the magnetic drive, whereby the magnetic core 6 moves upward. Thereby, by means of the shaft 7, the contact device 200 with the contact bridge 4, the holding element 30, the contact spring 34 and the lower yoke element 40 is also moved upwards, so that the contact bridge 4 is pressed against the fixed contact 2. The core 6, the shaft 7, the holding element 30, the contact spring 34 and the lower yoke element 40 then continue to move upwards until the core hits the yoke of the magnetic drive. Thereby, the contact springs 34 are further compressed and a sufficient contact force between the contacts 1 is ensured in order to continuously carry the nominal current. This state is a normal state of the switching device 100 in the on state, and is shown in fig. 6A and 6B.

By means of the current I flowing through the contact bridge 4, a magnetic flux MF is induced in the yoke elements 40, 50. By this magnetization, a detent force Frel, i.e. an attractive force, is induced between the yoke elements 40, 50, which detent force is directed against the spring force Fs of the contact spring 34. The greater the current I flowing through the contact bridge 4, the greater the active detent force Frel, i.e. the attractive force. However, since the contact spring 34 is intended to push the lower yoke element 40 away from the contact bridge 4 and thereby also from the upper yoke element 50, the spring force Fs can be greater than the detent force Frel between the yoke elements 40, 50 if the current I is sufficiently small. In this case, which represents normal operation, these movable parts remain in the positions shown in fig. 6A and 6B.

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

By appropriate selection of the spring constant of the contact spring 34, the geometrical design and dimensions of the yoke elements 40, 50 and the first distance L1, the current threshold of the current I can be adjusted until the state shown in fig. 6A and 6B is maintained and the air gap L remains open in the manner shown. Preferably, the current threshold is higher than the nominal current, and particularly preferably also higher than the small short-circuit current. For example, the current threshold may be several kiloamperes, such as 5kA. In the low short-circuit current range below this current threshold, the levitation force Flev pushing the contact bridge 4 away from the fixed contact 2 is small, so that the contact spring 34 alone can exert a force to hold the contact bridge 4 at the fixed contact 2.

If the current I through the contact bridge 4 finally exceeds this current threshold, i.e. a state exists in which the short-circuit current through the contact 1 increases, the detent force Frel also increases proportionally with the current I and exceeds the spring force Fs. Thereby, the lower yoke element 40 moves upward, i.e., toward the upper yoke element 50. Thereby, the size of the air gap L is reduced, whereby the magnetic flux MF is additionally increased. Thereby, the detent force Frel increases exponentially with respect to the spring force Fs. The contact spring 34 is further compressed, preferably until the lower yoke element 40 is placed on the underside of the contact bridge 4 or on the underside of the upper yoke element 50. As shown in fig. 6C and 6D, the air gap L corresponds to a smaller second distance L2 between the yoke elements 40, 50, which in this case may be minimal and even equal to 0 or approximately equal to 0. The contact force is now at a maximum and in particular so great that: the detent force Frel continues to exceed the levitation force Flev and the contact bridge 4 can continue to be pressed against the fixed contact 2. Only above a maximum short-circuit current, which may be in the range of 16kA or more, for example, the magnetic flux MF saturates the yoke elements 40, 50, and the levitation force Flev may exceed the detent force Frel, whereby the contact bridge 4 may lift from the fixed contact 2.

Thus, as described, the air gap L is variable in dependence on the current I flowing through the contact bridge 4, whereby the holding force is also variable. The method can be realized as follows: the additional holding force is "switched on" by the yoke elements 40, 50 only in the event of a short circuit above the current threshold, as a result of which the switching device 100 can carry a greater short-circuit current than in the known solutions.

According to other embodiments, features and embodiments described in connection with these figures may be combined with each other even if not all combinations are explicitly described. Furthermore, the embodiments described in connection with these figures may alternatively or additionally have other features as described in the general section.

The invention is not limited to these embodiments due to the description according to the embodiments. Rather, the invention comprises each new feature and each combination of features, which in particular comprises each combination of features in the patent claims, even if the feature or the combination itself is not explicitly specified in the patent claims or the embodiments.

List of reference numerals

1. Contact point

2. Fixed contact

3. Insulation body

4. Contact bridge

5. Armature iron

6. Magnetic core

7. Shaft

8. Coil

9. Magnetic yoke

10. Spring

11. Switch room

12. Switch chamber wall

13. Bottom of switch chamber

14. Airtight area

15. Interior space

16. Permanent magnet

18. Coil connecting end

19. Shell body

30. Holding element

31. Base seat

32. Clamping element

34. Contact spring

36. Guide element

37. Stop piece

38. An opening

39. Spring retainer

40. Lower yoke element

41. Recess portion

45. Constriction part

50. Upper yoke element

51. Welding flange

52. Recess portion

60. Air gap

90. Lateral direction

91. In the vertical direction

92. Longitudinal direction

93. Transverse direction

100. Switching device

200. Contact device

I current

Flev suspension force

Fs spring force

Frel magnetic resistance

Distance L1 and L2

MF magnetic flux

Claims

1. A switching device (100) having at least one fixed contact (2, 3), a contact bridge (4) and an upper yoke element (50) in a switching chamber (11), wherein

The upper yoke element is fixed at the switching chamber,

the upper yoke element has a recess (52) on the underside facing the contact bridge, and the contact bridge protrudes at least partially into the recess in the on-state of the switching device.

2. Switching device according to the preceding claim, wherein the upper yoke element is arranged laterally beside the at least one fixed contact.

3. A switching device according to any one of the preceding claims, wherein the switching device has two fixed contacts and the upper yoke element is arranged between the two fixed contacts.

4. Switching device according to the preceding claim, wherein the contact bridge has a constriction (45) which, in the on-state of the switching device, is arranged at least partially in a recess of the upper yoke element.

5. A switching device according to any one of the preceding claims, wherein the contact bridge in the on-state partially protrudes from the recess.

6. A switching device according to any one of the preceding claims, wherein the contact bridge has a thickness greater than the depth of the recess.

7. A switching device according to any one of the preceding claims, wherein the contact bridge is spaced apart from the upper yoke element in the on-state.

8. A switching device according to any one of the preceding claims, wherein the upper yoke element has a greater thickness above the contact bridge than the contact bridge.

9. A switching device according to any one of the preceding claims, wherein the upper yoke element is fixed at the switching chamber by means of welding, riveting, screwing, bonding or caulking.

10. Switching device according to any of the preceding claims,

wherein the switching device has a contact device (200) which can be moved by means of a shaft (7),

wherein the contact device has a holding element (30) and the contact bridge,

wherein the retaining element is fixed to the shaft and

wherein the contact bridge is displaceably arranged at the holding element.

11. Switching device according to the preceding claim, wherein the holding element has at least one guiding element (36) for guiding the contact bridge.

12. Switching device according to either of the two preceding claims, wherein the holding element has at least one stop (37) for limiting the displaceability of the contact bridge.

13. Switching device according to claims 11 and 12, wherein the holding element has at least one clamping element (32) with the at least one guide rail and the at least one stop, and the clamping element at least partially surrounds the contact bridge.

14. Switching device according to claim 12 or 13, wherein in the on-state of the switching device the at least one stop protrudes into the intermediate space between the at least one fixed contact and the upper yoke element.

15. Switching device according to any one of claims 10 to 14, wherein the contact device has a contact spring (34) which is arranged on the underside of the contact bridge facing away from the upper yoke element and presses the contact bridge in the direction of the at least one fixed contact.

16. Switching device according to claim 15, wherein the contact spring is supported directly on the underside of the contact bridge and/or directly at the holding element.

17. Switching device according to claim 15 or 16, wherein the holding element has a spring holder (39) which counteracts a displacement of the contact spring at the holding element, and wherein the spring holder has a peg which is surrounded by a portion of the contact spring.

18. The switching device according to any one of claims 10 to 14,

wherein the contact device further has a lower yoke element (40) which is displaceably arranged at the holding element and

Wherein, when the switching device is in operation, an air gap (L) between the lower yoke element and the upper yoke element is dependent on a current (I) flowing through the contact bridge.

19. The switching device of claim 18, wherein the contact bridge is disposed between the lower yoke element and the upper yoke element.

20. Switching device according to either of the two preceding claims, wherein a contact spring (34) is arranged between the contact bridge and the lower yoke element, which contact spring pushes the contact bridge and the lower yoke element away from each other.