DE102021214615A1 - arcing chamber of a mechanical switch - Google Patents

Abstract

The invention relates to an arcing chamber (22) of a mechanical switch (14) with a plurality of flat arcing strips (24) which are arranged parallel to one another and stacked one on top of the other in a stacking direction (28). The erasing strips (24) are made of ceramic. The invention also relates to a mechanical switch (14) and a method (44) for producing an arcing chamber (22).

Description

The invention relates to an arcing chamber of a mechanical switch and a mechanical switch. The invention also relates to a method for producing an arcing chamber.

From the DE 10 2009 013 337 B4 a circuit breaker for direct current and alternating current with two contact points is known. A contact bridge is arranged between the contact points and is moved in the transverse direction when the circuit breaker trips. The arcs that occur at the two contact points are driven by a blower device. In this case, one of the two arcs is blown up to an edge region of the contact bridge, whereas one of the base points of the other arc is essentially brought into electrical contact with the two contact points by means of baffles. In other words, the two contact points are electrically short-circuited by means of the second arc and the second arc takes over the electrical function of the contact bridge in the closed state. The second arc is thus connected in parallel with the contact bridge. As a result, the first of the two arcs is extinguished. The remaining arc is driven into an arcing chamber with a stack of arc splitters by means of a further blowing device and is extinguished there by means of the stack of arc splitters.

The stack of arc splitters is formed by means of a plurality of arc splitters which are stacked one on top of the other in a stacking direction and are made of an electrically conductive material, usually a ferromagnetic material. The arc is divided into several partial arcs by means of the arc splitters, which leads to a multiplication of the electrical voltage required to maintain the arc.

A specific electrical voltage is required to maintain these partial arcs, which is usually between 20 V and 30 V and is dependent on the electrical current carried. If, for example, 12 such arc splitters are present, an electrical voltage of 220 V that is present can be reliably interrupted. So that the arc splitters are not damaged or at least any burn-off is comparatively small, so that a plurality of switching processes can be carried out, the splitter plates must have a specific thickness. With 12 quenching plates, this results in a minimum size of the quenching chamber of 25mm in the stacking direction. If higher electrical voltages are to be switched safely, more arc splitters are required, which is why the size of the arcing chamber also increases.

The invention is based on the object of specifying a particularly suitable quenching chamber and a particularly suitable mechanical switch as well as a particularly suitable method for producing a quenching chamber circuit breaker, the size being reduced and/or production costs being reduced.

With regard to the arcing chamber, the object is achieved by the features of claim 1, with regard to the mechanical switch by the features of claim 8 and with regard to the method by the features of claim 9. Advantageous developments and refinements are the subject of the respective dependent claims.

In the intended state, the arcing chamber is a component of a mechanical switch and is suitable for this purpose, in particular provided and set up. The mechanical switch has a fixed contact and a moving contact that is mounted so that it can move, which are electrically connected in series and serve to carry current within the mechanical switch. For example, the fixed contact is held in place by means of additional elements of the mechanical switch. The moving contact is preferably movably mounted by means of a hinge, for example a film hinge or the like. Alternatively or in combination with this, the moving contact can be moved in a transverse direction with respect to the fixed contact.

In the electrically conductive state of the mechanical switch, the two contacts are preferably mechanically in direct contact with one another and are spaced apart from one another in the non-conductive state. In this case, the contacts are brought to one another in an opening direction. The opening direction is understood in particular as meaning the direction in which the moving contact is moved with respect to the fixed contact in order to convert the mechanical switch from the (electrically) conductive to the non-conductive state. For example, the moving contact is moved transversally with respect to the fixed contact. Here, the opening direction denotes the direction that is parallel to the transversal straight line. Alternatively, the moving contact is rotated with respect to the fixed contact, in particular by means of a hinge or a fixed axis. In this case, the opening direction is tangential to the axis of rotation.

The arcing chamber has extinguishing strips stacked one on top of the other in a stacking direction, that is to say a plurality of extinguishing strips, in particular at least at least two erasing strips and suitably less than 100 erasing strips. Preferably the number of erasing strips is between 5 and 80, between 8 and 50 or between 10 and 30. Suitably the number of erasing strips is less than or equal to 20.

The erasing strips are flat and therefore only extend in one plane. Perpendicular to this plane, the extent of each eraser strip is reduced and the extent, also referred to as thickness, is suitably less than or equal to 2mm, 1.5mm or 1mm. The erasing strips are expediently arranged perpendicularly to the stacking direction and parallel to one another. The projections of the erasing strips preferably overlap parallel to the stacking direction at least partially, preferably completely. A comparatively compact arcing chamber is thus provided.

The erasing strips are made of a ceramic that is, in particular, electrically non-conductive and preferably thermally conductive. An oxide ceramic such as, for example, an aluminum oxide ceramic (Al2O3) is particularly preferably used as the ceramic.

The arcing chamber is used in particular to extinguish an arc that occurs, for example, when any mechanical switch is actuated. For this purpose, the arcing chamber is expediently suitable, in particular provided and set up. For example, the quenching chamber comprises a driving element for driving the arc that is produced, for example during a switching operation of any mechanical switch, to or between the extinguishing strips.

During operation, the arc is not partially intercepted by means of the extinguishing strips due to the formation of the extinguishing strip as an electrical insulator, so that a number of partial arcs are formed. Rather, due to the electrically insulating properties of the extinguishing strips, the arc is deformed, in particular bent, so that the length of the arc is increased. Due to the increased length of the arc and the associated higher electrical voltage required, it is possible for the arc to go out. Thus, when the arc is extinguished, it has a length that can otherwise only be achieved with an enlarged arcing chamber.

In addition, the arc is cooled by means of the quenching strips, namely the plasma required to form the arc. As a result, the electrical voltage required to maintain the arc also increases, and upon sufficient cooling, the arc is extinguished. Due to the thermal conductivity of the quenching strips, the heat is efficiently transported away from the area of the quenching strips in which the heat input from the arc into the respective quenching strips takes place. As a result, a cooling effect is further improved, so that the arc is reliably extinguished even with a reduced size of the arcing chamber. In addition, because of the separate erasing strips, even if the heating is irregular, any mechanical stress that develops as a result is limited to the individual erasing strips. Therefore, even with a comparatively large temperature difference between the individual erasing strips, no mechanical stress develops between them that could lead to destruction. As a result, stability and operational reliability are increased.

The erasing strips are preferably surrounded by two metal plates which are arranged parallel to the stacking direction and to one another and are made of a ferromagnetic metal, for example. The metal plates are used to at least partially shape the magnetic field that is created by the arc to be extinguished, so that the arc is driven accelerated between the extinguishing strips.

For example, the erase strips are each rectangular, which simplifies manufacture. Particularly preferably, however, these are at least partially V-shaped and thus have a notch. The notch is expediently located on the side that first comes into contact with the arc during operation. Thus, a bending or other deformation of the arc essentially only occurs when the arc is already in the notch, and a movement of the arc away from the extinguishing strip is thus avoided by means of the notch. As a result, functional reliability is further increased.

In one embodiment, the erasing strips are spaced apart from one another in the stacking direction, so that a free space is formed between the individual erasing strips. In this case, the thickness of the free space, ie the extent in the stacking direction, is preferably greater than or equal to the thickness of the erasing strips, 1.5 times or twice the erasing strips. In this way, a comparatively extensive deformation of the arc is also possible, so that it has a comparatively great length. In particular, the arc is bent in a U- or V-shape between adjacent extinguishing strips. In this way, it is also possible to introduce heat into the respective erasing strips over a comparatively large length, which is why comparatively efficient cooling takes place. Due to the distance The weight of the arcing chamber is also reduced by connecting the extinguishing strips to each other.

For example, the extinguishing strips are different from one another or particularly preferably identical in construction to one another. In this way, identical parts can be used, which is why manufacturing costs are reduced. Due to the spacing of the quenching strips from one another in the stacking direction, comparatively large spatial areas are provided into which the arc can be guided, so that its length is increased.

In an alternative to this, the erasing strips abut one another and are thus layered to form a stack. For example, in this case the erasing strips are attached to one another, for example by means of gluing, or they are only loosely in contact with one another. The stack itself has a plurality of chambers lying one above the other and separated from one another in the stacking direction, which are thus spaced apart from one another in the stacking direction. The chambers are designed in such a way that the arc is directed into them during operation, so that a spatial area is available for the arc to be extended. In this case, the individual partial areas of the arc arranged in the chambers are connected to sections encompassing the respective edges of the chambers. In other words, the arcing chamber is designed in such a way that the arc is forced into the individual chambers, so that the arc is widened and its length is increased. Because of the stack, stability of the arcing chamber is increased and installation space is reduced.

In particular, the chambers are open on the side of the stack on which the arc is when it is formed and on which the arc thus strikes. In other words, the chambers are open on the side of the stack facing the point at which the arc originates or at least the direction in which the arc impinges.

Because the erasing strips are stacked on top of one another, the stack preferably has a plurality of layers arranged perpendicular to the stacking direction and stacked on top of one another. For example, each of the layers is formed by means of an erasing strip. The chambers are designed, for example, like blind holes and thus have a closed end, which is in particular the end of the stack facing away from the point of origin of the arc. For example, in this case the erase strips are structurally identical to one another. For example, the recesses of each extinguishing strip that form the respective chamber are laterally offset. In this case, in particular, superimposed erasing strips, or at least some of them, are rotated relative to one another, so that the chambers that are separate from one another are formed. As an alternative to this, at least some of the erasing strips are different, so that the individual chambers spaced apart from one another are formed.

In an alternative, each layer expediently has two of the erasing strips. In this case, each layer comprises, for example, further erasing strips or particularly preferably only the two erasing strips. The two erasing strips of the respective layer are expediently spaced apart from one another, so that the respective chamber is at least partially formed between them. As an alternative to this, the two erasing strips of each layer rest against one another at least in sections, and the respective chamber is also designed here like a blind hole.

The layers are suitably divided into several groups, with the layers of the same group lying against one another and being structurally identical to one another. As a result, an expansion of the chambers in the stacking direction is increased. Consequently, a comparatively large spatial area is available for the formation of the arc, so that it is actually bent in a U/V shape. For example, between two and five such layers are associated with each of the groups, with the stack having, for example, between two and five such groups.

For example, the erasing strips of each layer are structurally identical to one another or particularly preferably different from one another. As a result, the layers are particularly asymmetrical and the resulting chambers are at least partially offset laterally. The same erasing strips are preferably assigned to each of the layers, so that only two different types of erasing strips are present. With a different arrangement of the extinguishing strips of the respective layer, it is thus possible to form the chambers that are separated from one another. In particular, the layers are also divided into groups, with the layers of the same group not differing, and with the layers of each group being stacked directly on top of one another. Thus, in particular, the next-but-one groups in the stacking direction are constructed identically to one another. Due to the same deletion strips, the number of identical parts is increased, which is why manufacturing costs are reduced.

Particularly preferably, the arcing chamber additionally has two groups or at least two layers, which form the end of the stack in the stacking direction at opposite ends. These each include an erasing strip with a different shape, the erasing strips being configured, for example, rectangular. As a result, the arc is deformed again at the end, with the position of the end points of the arc being constant even if the arc is introduced comparatively deep into the stack. This also makes it easy to assemble the stack on other components.

For example, the erasing strips are fastened to one another, or a rod to which the erasing strips are fastened protrudes through them, for example. In this case, in particular, the rod is pressed into a hole in each of the erasing strips and/or a press package is implemented using the rod and the erasing strips. Particularly preferably, however, the arcing chamber includes a holder by means of which the arcing strips are each held at the edges. In this case, in particular, the holder is made of a ceramic, so that it is also burn-proof. Alternatively, the holder is made of some other material that is expediently electrically non-conductive. The ceramic is preferably made of a polyamide, such as PA 12 or PA 6.6. The arcing chamber expediently comprises two holders of this type, which are located on opposite sides of the erasing strips, so that the erasing strips are held between them. Stability is increased due to the two holders. In particular, the two holders are constructed identically or as mirror images of one another. Suitably the holder or holders are arranged parallel to the direction in which the arc is moved relative to the erasing strips for extinguishing. This means that the arc is not prevented from being quenched by the holders.

For example, the eraser strips are spaced from one another and the holder has a plurality of grooves, with each of the eraser strips being inserted into an associated one of the grooves. Thus, construction and assembly is simplified. The holder or holders suitably has a plurality of such grooves, with one of the erasing strips lying in each groove at the edge, for example. Alternatively, some of the grooves are free of the eraser strip. Due to the majority of grooves, it is therefore possible to select the number and position of the extinguishing strips for the respective application, so that the arcing chamber can be configured for a large number of different applications. A redesign is not necessary, it is only necessary to select the number and position of the erasing strips accordingly. Thus, manufacturing costs are reduced.

As an alternative to this, the erasing strips are joined together to form the stack, and the stack is gripped by the holder, so that the erasing strips are stabilized relative to one another by the holder. Thus, a number of required parts and manufacturing steps are reduced.

For example, any driving element is also held by the holder, in particular a permanent magnet, so that an interaction between the driving element and the arc is improved when this is located between the extinguishing strips.

The mechanical switch, which in particular is also simply referred to below as a switch, has a fixed contact and a moving contact, which is connected, for example, to a contact bridge that is movably mounted with respect to the fixed contact. At least the moving contact is movably mounted to the fixed contact, namely by means of the contact bridge. For example, the moving contact is welded to the contact bridge and, for example, is in one piece with it. As an alternative to this, the moving contact is made from a material that differs from the contact bridge. For example, the fixed contact is fixed and its position is therefore rigid. As an alternative to this, the position of the fixed contact is also variable, and this is movably mounted, for example, by means of a further bridge or other mechanical conditions. In this case, it is in particular possible to bring the moving contact into direct mechanical contact with the fixed contact, so that they are mechanically in direct contact with one another. Consequently, the fixed contact and the moving contact are electrically connected to each other, and the mechanical switch is in the electrically conductive state. When the moving contact is spaced apart from the fixed contact, they are no longer in direct electrical contact with one another, and the electrical switch is in the electrically non-conductive state.

The mechanical switch preferably includes a housing which is made of a plastic, for example, and within which both the fixed contact and the moving contact are arranged. In this case, the contact bridge is expediently mounted on the housing by means of a hinge or other bearing, for example a sliding bearing. In a development, a guide is formed by means of the housing itself, by means of which the contact bridge is mounted. The fixed contact is particularly preferably arranged rigidly on the housing or at least immovably with respect to the housing, which is why a construction is simplified. For example, the contact bridge is mechanically connected directly to a rigid (possible) busbar of the main current path and thus in particular to one of the possible connections. For the purpose of movable mounting, the contact bridge is expediently mounted in a pivotable manner.

The mechanical switch has an arcing chamber with a plurality of flat arcing strips which are arranged parallel to one another and stacked one on top of the other in a stacking direction. the delete strips are made of a ceramic such as Al2O3. When the mechanical switch is switched from the (electrically) conductive to the non-conductive state, it is possible for a plasma to be formed between the fixed contact and the moving contact due to a comparatively high electrical voltage, and thus an arc to form through which an electrical current flows. As a result, there is a current flow through the mechanical switch even when the contacts are open, ie when the moving contact is mechanically spaced from the fixed contact. The arc is suitably driven into the quenching chamber due to a magnetic field generated, for example, by the arc itself. The mechanical switch is expediently designed accordingly. For example, the moving contact and the fixed contact are arranged accordingly for this purpose. Alternatively or in combination, a drive element such as a permanent magnet and/or an electrical coil or choke is also present, for example, which is also referred to as a blow-out field coil. For example, the coil/choke is powered by the electrical current carried by the mechanical switch, particularly via the arc. In summary, the arcing chamber, any driving element and the two contacts are suitably arranged such that an arc occurring when the two contacts are opened (spacing) is driven by the driving element into the arcing chamber, preferably between the extinguishing strips.

When the arc enters the arcing chamber, it cannot spread into the extinguishing strips themselves due to the electrical insulating effect of the extinguishing strips made of ceramic. As a result, the arc is deformed by means of the quenching strips and is thus stretched. As a result, the electrical voltage required to sustain the arc increases.

Heat exchange also takes place between the plasma and the erase strips. The cooling of the plasma and the associated energy withdrawal ensure an increase in the electrical field strength of the arc. Since the extinguishing strips are made of a thermally conductive material, the individual extinguishing strips are not only heated locally, but rather in a comparatively large volume, which is why a comparatively high energy extraction takes place. However, since the extinguishing strips of the arcing chamber are separate from one another and each have a limited thickness, i.e. their extent in the stacking direction, such as a maximum of 2 mm, 1.5 mm or 1 mm, the mechanical stresses that occur due to uneven heating are limited. Consequently, even if the energy input from the arc to the individual extinguishing strips differs, excessive mechanical stress is prevented from developing in the arcing chamber, which could otherwise lead to destruction.

The increase in electric field strength leads to a sharp and rapid increase in arc voltage. As soon as the arc voltage reaches or exceeds the value of the electrical voltage applied to the mechanical switch, this leads to a limitation and reduction of the current flow up to and including its interruption. In summary, due to the increased arc voltage, the arc is quenched and consequently the mechanical switch is (actually) placed in the non-conductive state.

Preferably, the mechanical switch is part of a circuit breaker, and the invention also relates in particular to such a circuit breaker. The circuit breaker is used in particular to safeguard, ie protect, an electrical line and/or a component such as a device. In other words, the circuit breaker is a line circuit breaker or a device circuit breaker. In this case, the housing of the switch is suitably formed by means of the housing of the circuit breaker. The circuit breaker expediently has a control unit, by means of which the mechanical switch is controlled as a function of certain circumstances, for example in the event of an overcurrent or an overvoltage. The control unit is formed, for example, by means of a drive and/or a control unit. The control unit includes a sensor, for example, the drive being actuated as a function of the value detected by the sensor, and as a result the mechanical switch being opened.

The circuit breaker is preferably designed for direct current interruption and is, for example, only unidirectional or particularly preferably bidirectional. A maximum electrical voltage that can be switched by means of the circuit breaker is particularly preferably greater than 100 V, 200 V or 500 V. For example, the maximum electrical voltage that can be switched by means of the circuit breaker is less than 3500 V or 3000 V. The circuit breaker is suitable for this, in particular intended and furnished.

The circuit breaker is particularly preferably used in a motor vehicle, in particular in an on-board network, by means of which an electrical direct current is conducted. The circuit breaker is particularly preferably a component of a high-voltage vehicle electrical system of the motor vehicle and is used in particular to protect a high-voltage battery and/or a Electric motor of a motor vehicle, by means of which a drive takes place, for example. The motor vehicle is, for example, a ship, boat or aircraft. However, the motor vehicle is particularly preferably land-based and, for example, rail-guided. In this case, the motor vehicle is, for example, a railcar, a locomotive, a train or a tram. Alternatively, the motor vehicle can be moved independently of rails or the like. The motor vehicle is expediently a passenger car (car) or particularly preferably a commercial vehicle, such as a bus or a truck (truck). Furthermore, the invention also relates to the use of such a circuit breaker for protecting a high-voltage vehicle electrical system of a motor vehicle and a speaking motor vehicle.

The method is used to produce an arcing chamber of a mechanical switch, the arcing chamber having a plurality of flat arcing strips which are arranged parallel to one another and stacked one on top of the other in a stacking direction. The erasing strips are made of ceramic.

The method provides that a ceramic plate is initially provided. In this case, the ceramic plate is rigid and, in particular, already fired. The ceramic plate is thus designed to be comparatively stable. In a subsequent work step, the ceramic plate is separated to produce at least some of the erasing strips, so that at least two or more erasing strips are produced from the ceramic plate. Particularly preferably, a large number of such erasing strips are each produced from a corresponding ceramic plate, for example at least 5, 10 or 20 such erasing strips. If the quenching chamber has more quenching strips than can be created from one ceramic plate, one or more further ceramic plates are expediently used, which are also separated to produce the quenching strips. Subsequently, the erasing strips are arranged parallel to each other and stacked one on top of the other in the stacking direction. In other words, the erasing strips are put together and, in particular, stabilized relative to one another, preferably by means of any holder.

In the process, the erasing strips are only detached from the ceramic plate after the end, so that no green body is required for the individual erasing strips. In this way, a burning process is simplified. Also, when determining the size of the erasing strips, shrinkage that occurs due to the firing process does not have to be taken into account. In other words, there is no change in the size of the erase strips. As a result, manufacturing tolerances can be selected to be comparatively small.

An aluminum oxide ceramic is preferably used as the material of the ceramic plate. It is thus possible to use a plate as the ceramic plate which can also be used, for example, as a carrier in the manufacture of printed circuit boards or in the manufacture of semiconductors. In other words, such ceramic plates are already available, which are therefore only used for other purposes. Consequently, it is possible to manufacture the arcing chamber with components that are already present, which is why manufacturing costs are reduced. In particular, the invention therefore also relates to the use of a ceramic plate from the production of printed circuit boards or semiconductors for the production of an arcing chamber.

For example, the ceramic plate is cut open to produce the erasing strips. In other words, the erasing strips are cut out of the ceramic plate. For example, this is done using a saw. Particularly preferably, however, the ceramic plate is only initially scored, so that the ceramic plate is structurally weakened in the area of the scratch. The contour of the scratch corresponds to the contour of the erasing strip to be produced. The ceramic plate is then broken at the scribe(s) so that the erasing strips are formed.

The ceramic plate is preferably scored and/or cut by means of a laser or, for example, by means of a water jet. As a result, formation of chips or the like and wear are reduced. Consequently, it is possible to produce the arcing chamber in a cost-effective manner. This also makes it possible to produce comparatively small extinguishing strips, so that the size of the arcing chamber is reduced.

The developments and advantages explained with regard to the arcing chamber can also be transferred to the mechanical switch/the circuit breaker/the method as well as to each other and vice versa.

• 1 schematisch vereinfacht einen Schaltkreis mit einem Schutzschalter, der einen mechanischen Schalter mit einer Löschkammer umfasst,
• 2 den mechanischen Schalter in einer Schnittdarstellung, der eine mehrere Löschstreifen aufweisende Löschkammer umfasst,
• 3 perspektivisch die in zwei Haltern gehaltenen Löschstreifen,
• 4 in einer Draufsicht einen der Löschstreifen,
• 5 ein Verfahren zur Herstellung der Löschkammer,
• 6 in einer Draufsicht eine Keramikplatte,
• 7 perspektivisch eine alternative Ausführungsform der Löschkammer,
• 8 in einer Draufsicht eine Lage eines Stapels, die zwei Löschstreifen aufweist,
• 9 perspektivisch die Löschkammer gemäß 7, wobei einer der Halter weggelassen ist,
• 10, 11 aus unterschiedlichen Perspektiven jeweils einen der Halter der Löschkammer gemäß 7, und
• 12, 13 perspektivisch eine jeweils alternative Ausführungsform des Stapels.

Exemplary embodiments of the invention are explained in more detail below with reference to a drawing. Show in it:

• 1 schematically simplified circuit with a circuit breaker comprising a mechanical switch with an arcing chamber,
• 2 the mechanical switch in a sectional view, which comprises an arcing chamber having several arcing strips,
• 3 in perspective the extinguishing strips held in two holders,
• 4 in a plan view one of the extinguishing strips,
• 5 a method for manufacturing the arcing chamber,
• 6 in a plan view a ceramic plate,
• 7 in perspective an alternative embodiment of the arcing chamber,
• 8th in a top view, a layer of a stack that has two erasing strips,
• 9 in perspective the quenching chamber according to 7 , with one of the holders omitted,
• 10 , 11 according to one of the holders of the arcing chamber from different perspectives 7 , and
• 12 , 13 in perspective an alternative embodiment of the stack.

Corresponding parts are provided with the same reference symbols in all figures.

In 1 a circuit 2 with a current source 4 is shown schematically simplified. A direct current with a nominal voltage of 400 A is provided by means of the power source 4, the electrical voltage present between the two poles of the power source 4 being up to 1000 V. The switching circuit 2 also has a load 6 which is thus operated by means of the current source 4 . The circuit further includes a circuit breaker 8 electrically connected in series with the load 6 and in parallel with the power source 4 . Circuit 2 is protected by circuit breaker 8 . In the event of a malfunction of the load 6 or other other components of the circuit 2, an overcurrent would flow through the electrical lines 10, which could damage the load 6, the power source 4 or other components that could damage the electrical line 10. Such a fault is detected by means of the circuit breaker 8 . For this purpose, the circuit breaker 8 includes a control unit 12, by means of which the electric current flowing through the circuit breaker 8 is monitored.

The control unit 12 includes a magnetic field sensor, a current sensor and/or a voltage sensor. Based on the measured values, a microcontroller of the control unit 12 is used to check whether there is a fault, such as an overcurrent. In this case, a drive of the control unit 12 is operated, by means of which a mechanical switch 14 is switched to interrupt the flow of current. Here, a moving contact 16 is spaced from a fixed contact 18 of the mechanical switch 14, so that they no longer bear against one another mechanically. It is possible here for an arc 20 to form, so that current continues to flow via the circuit breaker 8 . To extinguish the arc 20 , the mechanical switch 14 has an arcing chamber 22 with a plurality of extinguishing strips 24 . To protect the circuit breaker 8 from mechanical influences and to protect the objects surrounding the circuit breaker 8, the arcing chamber 22 and the other components of the mechanical switch 14 and the control unit 12 are arranged inside a housing 26 made of plastic.

In 2 is shown in a longitudinal section perpendicular to a stacking direction 28 of the mechanical switches 14 . This has a first busbar 30 which is made of copper, which is bent in a U-shape and is arranged essentially perpendicularly to the stacking direction 28 . The fixed contact 18 is rigidly fastened to the first busbar 30 in the area of the bend.

The moving contact 16 is fastened to a contact bridge 32 arranged parallel to the first busbar 30 and above it in the stacking direction 28 . In this case, the contact bridge 32 is mounted so that it can be displaced longitudinally in the stacking direction 28, so that direct mechanical contact can be established and released between the moving contact 16 and the fixed contact 18. Furthermore, the mechanical switch 14 has a second busbar 34, the contact bridge 32 being arranged in the stacking direction 28 between the two busbars 30, 34. The contact bridge 32 and the second busbar 34 are also made of copper.

The second busbar 34 is arranged so that it is electrically insulated from other components of the mechanical switch 14 and is arranged parallel to the contact bridge 32 in the area in which they overlap in the stacking direction 28 . In the area projecting beyond the contact bridge 32, the second busbar 34 is bent, so that a distance from the first busbar 30 is increased. In a variant that is not shown, the second busbar 34 is electrically contacted with the contact bridge 32 or other components, preferably by means of a stranded wire.

The arcing chamber 22 is arranged in the stacking direction 28 between the free end of the second busbar 34 and the first busbar 30 3 is shown in perspective. The arcing chamber 22 has two holders 36 which are constructed as mirror images of one another and are made of a ceramic material, with the two holders 36 being essentially cuboid. Here, the main extension plane of the two holders 36 is parallel to Ver run of the first busbar 30 and to the stacking direction 28. In the mutually facing surfaces of the holder 36, a plurality of grooves 38 running parallel to the first busbar 34 are made, in the example shown 12. In each second of the grooves 38 in the stacking direction 28 is one the mutually identical erase strips 24 are inserted. Consequently, there are six erase strips 24 in total. The erasing strips 24 protrude beyond the holders 36 on the side facing the second busbar 34 . By means of the grooves 38, the erasing strips 24, which are flat, are aligned perpendicular to the stacking direction 28. The thickness of the erasing strips 24, ie their extent parallel to the stacking direction 28, is less than 2 mm, namely 1 mm. Due to the two holders 36 and the grooves 38 lying one above the other in the stacking direction 28, the erasing strips 24 are also arranged in parallel, and their projection onto one another parallel to the stacking direction 28 completely overlaps each other.

In summary, the erasing strips 24 are each held at the edge by means of the two holders 36 . Due to the respective grooves 28 left free between adjacent erasing strips 24, these are spaced apart from one another in the stacking direction 28. For assembly, the erasing strips 24 are pushed into the respective grooves 38, with no additional fastening means being required, which is why production is simplified. Due to the excess number of grooves 38, it is also possible here to configure the arcing chamber 22 in a different way and, for example, to use an increased number of arcing strips 24, with their spacing in the stacking direction 28 thus being reduced.

One of the erase strips 24, which are identical in construction, is in 4 shown in a plan view. The erasing strips 24 are made of the same ceramic as the holders 36, namely aluminum oxide (Al2O3). Each extinguishing strip 24 has a notch 39 on the side facing the second busbar 34 , which is located centrally between the two holders 36 . On the side facing away from the notch 39, a rod-shaped holding element 40 made of a plastic is fastened to each of the quenching plates 24, by means of which the combination of the quenching strips 24 and the holders 36 can be fastened to other components of the quenching chamber 22.

Two metal plates 41 which are electrically insulated from the busbars 30, 34 and the contact bridge 32 are arranged parallel to the holders 36. The two metal plates 41 are made of a ferromagnetic material, namely iron, and the two holders 36 and the two bus bars 30, 34 are partially arranged between the two metal plates 41. In a variant that is not shown in detail, a driving element, namely a permanent magnet, is arranged on at least one of the metal plates 41, by means of which the associated metal plates 41 are magnetized.

When the mechanical switch 14 is opened, ie when the moving contact 16 is spaced from the fixed contact 18, for which the contact bridge 32 is moved accordingly, it is possible for the arc 20 to form between the moving contact 16 and the fixed contact 18. Consequently, there is still a current flow between the first busbar 30 and the contact bridge 32 and thus via the circuit breaker 8. Due to the magnetic field created by the arc 20, which interacts with the metal plates 41, and/or due to the driving element, the arc 20 is directed in the direction of the Delete strips 24 bulged. With increasing deformation, the arc 20 jumps from the contact bridge 32 to the second busbar 34, which is electrically connected to the contact bridge 32 by means of a further arc 42 that forms.

Because of the magnetic fields, the arc 20 formed between the first busbar 30 and the second busbar 34 is moved further in the direction of the extinguishing strips 24 until it strikes the extinguishing strips 24 in the area of the notches 39 . At this point in time, the course of the arc 20 is essentially parallel to the stacking direction 28, ie in a straight line, with the length of the arc 20 being increased. Since the quenching strips 24 are made of electrically non-conductive ceramic, the arc 20 is prevented from moving further in the area where it strikes the respective quenching strip 24 . However, the arc 20 is moved into the spaces formed between the erasing strips 24 in the stacking direction 28 and is consequently deformed into a U-shape, so that the length of the arc 20 further increases.

In addition, thermal energy is withdrawn from the arc 20 by means of the quenching strips 24 since the thermally conductive quenching strips 24 absorb the heat of the arc 20 . In this case, the individual erasing strips 24 are heated essentially uniformly, so that a comparatively large amount of thermal energy is absorbed by each of the erasing strips 24 . In this case, mechanical stresses do not form, even if the individual erasing strips 24 are heated differently from one another, since they are mechanically separated from one another.

As a result of the cooling and the increase in the length of the arc 20 , the electrical voltage required to maintain the arc 20 increases until it exceeds the electrical voltage provided by the power source 4 exceeds. As a result, the arc 20 is extinguished and subsequently also the further arc 42. The flow of current through the circuit breaker 8 is thus interrupted.

In 5 a method 44 for producing the arcing chamber 22 is shown. In a first step 46, an in 6 Ceramic plate 48 shown in a plan view is provided. The ceramic plate 48 consists of an aluminum oxide and has a thickness between 1 mm and 2 mm. Such a ceramic plate 48 is also used for the production of printed circuit boards or as a substrate for semiconductors. Consequently, as the ceramic plate 48, a component from the circuit board or semiconductor production can be used.

In a subsequent second work step 50, the contour 52 of a plurality of erasing strips 24 is scratched into the ceramic plate 48. Either a laser or a water jet cutter is used for this. The ceramic plate 48 is thus structurally weakened in the area of the contour 52 by means of the laser or the water jet cutter. However, the ceramic plate 48 is not completely severed there, so that on the one hand the time required to produce the contour 52 is shortened. On the other hand, when cutting, it is only necessary to hold the entire ceramic plate 48, and therefore a labor is reduced. The ceramic plate 48 is then broken at the contours 52 so that the ceramic plate 48 is separated, with a total of six such erasing strips 24 being broken out of the ceramic plate 48 in the example shown here. The breaking out is possible in a comparatively short time.

If more than the six extinguishing strips 24 are required to produce the arcing chamber 22, another ceramic plate 48 is broken accordingly. If, on the other hand, fewer arcing strips 24 are required, the remaining arcing strips 24 are used for another of the arcing chambers 22 . The holding elements 40 are then fastened to the erasing strips 24 produced in this way, so that the erasing strips 24 can subsequently be moved by means of the holding elements 40 .

In a subsequent third work step 54, the erasing strips 24 are arranged parallel to one another and stacked one on top of the other in the stacking direction 28. For this purpose, the erasing strips 24 are inserted into the corresponding grooves 38, the erasing strips 24 being arranged accordingly by means of the insertion. The extinguishing strips 24 are also attached to the respective holders 36. In addition, the metal plates 41 are additionally arranged or other further activities are carried out.

In 7 an alternative embodiment of the arcing chamber 22 is shown in perspective. In this variant, the erasing strips 24 are also stacked one on top of the other in the stacking direction 28, the erasing strips 24 lying directly against one another, so that a stack 56 is formed. The stack 56 thus has a plurality of layers 58 which are arranged one above the other in the stacking direction 28 and are therefore arranged perpendicularly to the stacking direction 82 .

Of the layers 58, one is in 8th shown in a plan view, ie along the stacking direction 28 . Two of the erasing strips 24 are assigned to each of the layers 58 . The two erasing strips 24 of each layer 58 are different from one another, and one of the erasing strips 24 is wedge-shaped and the remaining one is trapezoidal. In other words, the erasing strips 24 associated with each of the layers 58 differ, but each layer 58 is associated with the same erasing strips 24, i.e. the same type the wedge-shaped and the trapezoidal-shaped, and these are divided equally among the plies 58.

The two extinguishing strips 24 of each layer 58 are spaced apart perpendicularly to the stacking direction 28 so that a slot 60 is formed between them, which runs parallel to the first busbar 30 in the assembled state. In the assembled state, four of the layers 58 are each combined into a group 62, with the erasing strips 24 of each group 62 being arranged flush with one another. The extinguishing strips 24 of the respectively adjacent group 62, on the other hand, are arranged mirror-inverted with respect to the direction in which the first busbar 30 runs, so that the stack 56 has a plurality of chambers 64 which are one above the other and are separated from one another in the stacking direction 28 and are each formed by means of the aligned slots 60. Due to the wedge or trapezoidal shape, the notches 39 continue to be formed in each of the layers 58 , which merge into the respective chambers 64 . A total of four such groups 62 are present, which are stabilized relative to one another by means of the holders 36 .

Each of the holders 36, of which in 9 one is not shown, surrounds the edge of the stack 56. In this variant, the holders 36 are made of plastic and each have a foot 66. The two holders 36 are fastened to one another at the respective foot 66, so that the stack 56 is held in a non-positive manner between the two holders 36 both in the stacking direction 28 and perpendicular thereto.

Each of the erasing strips 24 has two holes 68 that run parallel to the stacking direction 28 and are aligned with the respective holes 68 of the erasing strips 24 that are adjacent and directly adjacent in the stacking direction 28 . In the assembled state, rods (not shown in detail) are guided through them, which are stabilized by means of a holder 70 of the holder 36 . The rods are made of a polyamide. Each bracket 70 of the respective holder 36 has, as in 10 shown a bore and a U-shaped receptacle, by means of which the respective rod is held.

On the side opposite the stack 56, each of the holders 36, as shown in FIG 11 shown, a rectangular pot- or pan-shaped receptacle 72, within which rests a permanent magnet 74 in the assembled state, each forming one of the driving elements. During operation, the permanent magnets 74 interact with the magnetic field created by the arc 20 so that the latter is guided into the chambers 64 and is thus lengthened.

In 12 a modified embodiment of the stack 56 is shown. In this case, only three of the layers 58 are assigned to each of the groups 62, with the layers 58 not being changed. However, there are seven such groups 62 in total.

At the in 13 variant shown, each of the groups 62 are in turn assigned only three of the layers 58, with a total of five such groups 62 being present. These are each delimited at the end with respect to the stacking direction 28 by a further group 76 which each have three rectangular erasing strips 24 stacked one on top of the other and aligned with one another in the stacking direction 18 . Thus, the further groups 76 differ from the groups 62, and by means of the further groups 76 no chamber 64 is formed.

The invention is not limited to the exemplary embodiments described above. On the contrary, other variants of the invention can also be derived from this by a person skilled in the art without departing from the subject matter of the invention. In particular, all of the individual features described in connection with the individual exemplary embodiments can also be combined with one another in other ways without departing from the subject matter of the invention.

Reference List

2

circuit

4

power source

6

load

8th

circuit breaker

10

Management

12

control unit

14

mechanical switch

16

moving contact

18

fixed contact

20

Electric arc

22

arcing chamber

24

erase strips

26

Housing

28

stacking direction

30

first power rail

32

contact bridge

34

second power rail

36

holder

38

groove

39

score

40

holding element

41

metal plates

42

another arc

44

Proceedings

46

first step

48

ceramic plate

50

second step

52

contour

54

third step

56

stack

58

Position

60

slot

62

group

64

chamber

66

Foot

68

Hole

70

bracket

72

Recording

74

permanent magnet

76

another group

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102009013337 B4 [0002]

Claims (10)

Extinguishing chamber (22) of a mechanical switch (14), with a plurality of flat extinguishing strips (24) which are arranged parallel to one another and stacked one on top of the other in a stacking direction (28), and which are made of ceramic. arcing chamber (22) after claim 1 , characterized in that the erasing strips (24) are spaced apart from one another in the stacking direction (28). arcing chamber (22) after claim 2 , characterized in that the extinguishing strips (24) are structurally identical to one another. arcing chamber (22) after claim 1 , characterized in that the erasing strips (24) rest against one another and are layered to form a stack (56) which has a plurality of chambers (64) which are separated from one another and lie one above the other in the stacking direction (28). arcing chamber (22) after claim 4 , characterized in that the stack (56) has a plurality of layers (58) arranged perpendicularly to the stacking direction (28) and stacked one on top of the other, with each layer (58) being assigned two of the erasing strips (24). arcing chamber (22) after claim 5 , characterized in that the erasing strips (24) of each layer (58) differ, with each layer (58) being assigned the same erasing strips (24). Arcing chamber (22) according to one of Claims 1 until 6 , characterized in that the erasing strips (24) are held at the edge by means of a holder (36). Mechanical switch (14) with a fixed contact (18) and with a moving contact (16) mounted movably thereto and with an arcing chamber (22) according to one of Claims 1 until 7 . Method (44) for producing an arcing chamber (22) according to one of Claims 1 until 7 , in which - a ceramic plate (48) is provided, - the ceramic plate (48) is separated to produce at least some of the erasing strips (24), and - the erasing strips (24) are arranged parallel to one another and stacked on top of one another in the stacking direction (28). Method (44) according to claim 9 , characterized in that the ceramic plate (48) is first scored and then broken.

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