Switching unit

Abstract

The invention relates to a switching unit (10) comprising a fixed contact (30), a movable contact (24) that is mounted so as to be movable relative to the fixed contact, and a quenching element (58) which are all arranged in a quenching chamber (42). The fixed contact (30) is connected to a first limb (32) of a busbar (34) which is U-shaped at least in sections and therefore has a second limb (36). The switching unit (10) comprises a U-shaped magnetic circuit (56) for driving an arc formed between the fixed contact (30) and the movable contact (24) into the quenching element (58), the magnetic circuit (56) comprising a driving element (54) which is positioned between the first limb (32) and the second limb (36) and which is perpendicular to two parallel side surfaces (48) of the magnetic circuit (56). The quenching chamber (42) is positioned between the two side surfaces (48). The invention also relates to a module (40) of a switching unit (10) and to a circuit breaker (8).

Description

[0001] Description

[0002] switching unit

[0003] The invention relates to a switching unit with a fixed contact and a movable contact mounted relative thereto. Furthermore, the invention relates to a circuit breaker.

[0004] Motor vehicles, such as commercial vehicles, buses, and trucks, are increasingly using one or more electric motors as their primary propulsion, directly providing propulsion. A high-voltage battery is usually used to power the electric motor(s), providing a direct current of between 400 V and 800 V. The electrical currents flowing between the high-voltage battery and the electric motor during operation amount to several tens of amps.

[0005] In the event of a fault, such as a short circuit or an accident, it is necessary to electrically isolate the high-voltage battery from other components of the vehicle, such as the electric motor. This typically involves a circuit breaker with a switching unit integrated into a current path between the high-voltage battery and the electric motor. The circuit breaker is designed such that if the electrical current carried through the current path exceeds a certain limit, the switch is activated, thus preventing the flow of electrical current.

[0006] A semiconductor switch, for example, is provided as a switch. However, this causes comparatively high electrical losses during operation, which reduces the efficiency and thus also the range of the vehicle. Alternatively, a (mechanical) relay is provided as a switch, which has a fixed contact and a moving contact that is movably mounted relative to it. To interrupt the current flow, the moving contact is moved away from the fixed contact, thus creating a mechanical separation. As a result, a direct voltage begins to be applied between the fixed contact and the moving contact, which leads to ionization of the air between the two contacts. An electrical current in the form of an arc is possible via the ionized air, even though the two contacts are mechanically separated from each other.Thus, the other components of the vehicle continue to be powered by the high-voltage battery, which is why the desired safety is not achieved, at least not immediately. The arc also places thermal stress on the area surrounding the switch.

[0007] It is therefore necessary to extinguish the arc, should it have occurred, as quickly as possible. For this purpose, a quenching plate stack is usually used, which is arranged adjacent to the switch. The quenching plate stack comprises several individual quenching plates and a blowing device, for example in the form of an electric coil. This creates a magnetic field that acts on the arc, which acts as an electrical conductor. The electric coil is usually oriented in such a way that the acting Lorentz force drives the arc into the quenching plate stack. There, its length is increased, and it is possible that it is split into several individual (partial) arcs, each formed between adjacent quenching plates. As a result, the electrical voltage required to maintain the arc increases.If this voltage is greater than the electrical voltage between the moving contact and the fixed contact, the arc collapses, and the flow of electrical current is interrupted. To ensure the arc is reliably driven into the arc splitter stack, a precise and captive arrangement of the electrical coil is required, which makes manufacturing difficult.

[0008] The invention is based on the object of specifying a particularly suitable switching unit, a particularly suitable module of a switching unit, and a particularly suitable circuit breaker, wherein safety is advantageously increased and / or production is simplified. With regard to the switching unit, this object is achieved according to the invention by the features of claim 1, with regard to the module by the features of claim 6, and with regard to the circuit breaker by the features of claim 7. Advantageous further developments and refinements are the subject of the respective subclaims.

[0009] The switching unit has a fixed contact and a moving contact that is movably mounted relative to it. In particular, the fixed contact and the moving contact are part of a mechanical switch. At least the switching unit, in particular the switch, preferably has a mechanism by means of which the moving contact is movably mounted relative to the fixed contact. In particular, it is possible to position the moving contact such that it rests mechanically directly against the fixed contact. It is also possible, in particular, to space the moving contact from the fixed contact so that an air gap is formed between them. Preferably, a distance between the fixed contact and the moving contact is greater than or equal to 0.5 cm, 1 cm, or 2 cm. For example, during a movement, the moving contact is moved transversely relative to the fixed contact.However, it is particularly preferred that a rotational movement is also provided, so that the moving contact is pivoted relative to the fixed contact. This simplifies the design. When the switching unit is actuated, the position of the moving contact relative to the fixed contact is changed. When the switching unit is opened, the moving contact is preferably spaced apart from the fixed contact.

[0010] The switching unit further comprises an extinguishing element. The extinguishing element is made, for example, from a porous ceramic. However, the extinguishing element particularly preferably has a plurality of extinguishing strips stacked one above the other in a stacking direction. In particular, the extinguishing element thus comprises a plurality of extinguishing strips, in particular at least two extinguishing strips and suitably fewer than 100 extinguishing strips. Preferably, the number of extinguishing strips is between 5 and 80, between 8 and 50, or between 10 and 30. Suitably, the number of extinguishing strips is less than or equal to 20. The extinguishing strips are flat and thus each extend in only one plane. Perpendicular to this plane, the extent of each extinguishing strip is reduced, and the extent, which is also referred to as the thickness, is expediently less than or equal to 5 mm, 4 mm, 3 mm, 2 mm, 1.5 mm, or 1 mm.The extinguishing strips are expediently arranged perpendicular to the stacking direction and parallel to each other. Preferably, the projections of the extinguishing strips parallel to the stacking direction overlap at least partially, preferably completely. This provides a comparatively compact extinguishing chamber. The extinguishing strips are made, for example, from a ceramic that is, in particular, electrically non-conductive and preferably thermally conductive. An oxide ceramic, such as a silicate ceramic or an aluminum oxide ceramic (AlO3), is particularly preferably used as the ceramic. Cordierite is used as an alternative material.

[0011] Alternatively, the erasing strips are made of a metal, for example, iron, preferably an iron sheet. Suitably, the erasing strips are ferromagnetic. In another alternative, the erasing strips are made of different materials, for example, partly of a ceramic and partly of a metal. In particular, these are arranged alternately in the stacking direction.

[0012] For example, the erasing strips are arranged congruently with one another in the stacking direction and spaced apart from one another. Alternatively, they are arranged at least in groups, with only partial overlap between the groups. In particular, a meandering gap is formed between the individual groups. For example, the erasing element comprises a holder or the like, by means of which the individual erasing strips are stabilized relative to one another.

[0013] The switching unit further comprises an arcing chamber. The fixed contact, the moving contact, and the arcing element are arranged in the arcing chamber. In particular, the arcing chamber stabilizes the arcing element and at least the fixed contact relative to one another, which simplifies construction. The arcing chamber is expediently enclosed; in particular, at least the area between the arcing element and the moving contact and the fixed contact is enclosed. Thus, if an arc occurs between the moving contact and the fixed contact when the switching unit is actuated, it is enclosed by the arcing chamber, preventing uncontrolled spread of the arc. The arcing chamber also prevents thermal stress on other components. In particular, the arcing chamber is made of a plastic, preferably polybutylene terephthalate (PBT) or polyamide 66.

[0014] The switching unit further comprises a busbar which is U-shaped at least in sections. In particular, the busbar is U-shaped at its ends. Thus, the busbar has a first leg and a second leg which are essentially parallel to one another. In other words, the busbar is bent back on itself to form the two legs. The angle between the two legs is, for example, less than 20°, 15°, 10°, 5° or essentially equal to 0°. For example, the two legs are the same length or, expediently, the first leg is shortened. The fixed contact is connected to the first leg, in particular to its end. Suitably, the fixed contact is connected on the side of the first leg opposite the second leg. In particular, the busbar ends at the fixed contact.For example, the fixed contact is made of the same material as the busbars, and these are expediently molded together and, in particular, formed integrally. Alternatively, the fixed contact is made of a different material, for example, which increases resistance to arcing. The busbar is expediently made of copper or aluminum. In particular, a connector or the like for connecting the switching unit to other components of the circuit, such as a terminal or a plug, is attached to the end of the second leg.

[0015] The switching unit further comprises a U-shaped magnetic circuit for driving the arc formed between the fixed contact and the moving contact into the quenching element. In other words, the magnetic circuit is suitable, in particular provided and configured, to drive the arc into the quenching element, provided the arc is present between the fixed contact and the moving contact. In other words, the magnetic circuit drives the arc into the quenching element when it is formed due to the moving contact being separated from the fixed contact, i.e. in particular when the switching unit is switched / actuated. In particular, the magnetic circuit is thus designed such that the Lorentz force acting on the arc deforms / moves the arc, so that a portion of it reaches the quenching element.When the arc enters the quenching element, its length is increased, or, depending on the design of the quenching element, it is split into several arcs, so that the electrical voltage required to maintain the arc(s) increases. Alternatively, or in combination with this, the quenching element cools the arc, in particular any plasma, which also increases the electrical voltage required to maintain the arc.

[0016] The magnetic circuit is U-shaped, so that the magnetic field lines guided by the magnetic circuit are U-shaped. Between the ends of the magnetic circuit, the magnetic field lines emerge from the two parallel sides of the U-shape, where a substantially constant magnetic field is formed, and the magnetic field lines are substantially perpendicular to the two sides of the magnetic circuit.

[0017] The magnetic circuit comprises a driving element, by means of which in particular the magnetic field is provided. In this case, the driving element is, for example, a permanent magnet, which is made for example from a ferromagnetic material. In particular, the driving element is made of ferrite. In an alternative to this, the driving element is, for example, a neodymium magnet. If the switching unit is used, for example, to switch an alternating voltage, the driving element is in particular designed such that a magnetic field is provided due to induction therein. In this case, the driving element is made of steel. In particular, this results in a magnetic coupling with other components of the switching unit. The driving element is arranged between the first leg and the second leg.Preferably, the driving element is located in the region of a bend in the busbar, by means of which the LI shape is provided.

[0018] Furthermore, the magnetic circuit has two side surfaces that are magnetically coupled to the drive element. For example, these lie against one another or are expediently spaced a relatively small distance apart, for example less than 0.5 cm. The side surfaces are arranged parallel to one another, and the drive element is arranged perpendicular to them, thus creating the LI shape of the magnetic circuit. In particular, the two side surfaces are made of a ferromagnetic material, for example iron. Preferably, an iron sheet is used as the material for the two side surfaces. The arcing chamber is arranged between the two side surfaces. Due to this design of the magnetic circuit, the arcing chamber is essentially permeated by a constant magnetic field that extends between the two side surfaces and is perpendicular to them.

[0019] Due to the arrangement of the driving element between the two legs, a comparatively stable position is achieved, thus increasing robustness. Furthermore, this makes use of otherwise unused space, resulting in a comparatively compact switching unit. If an alternating current is carried via the switching unit, i.e. in particular if an alternating voltage is applied between the fixed contact and the moving contact, a magnetic field is comparatively effectively induced in the driving element due to the position between the two legs of the busbar. This magnetic field is in turn suitably shaped by the two side surfaces, so that the (magnetic) short circuit through the arcing chamber occurs. Consequently, no additional component is required, which reduces manufacturing costs.In summary, the design of the magnetic circuit and the arcing chamber ensures that the arc remains in the arcing chamber once it has been created. The arcing chamber is permeated by a substantially constant magnetic field, so that the arc is reliably driven into the arcing element. This increases safety. It is also possible to stabilize the individual components relative to one another, thus simplifying manufacturing. Furthermore, only a relatively small number of components are required, and comparatively large manufacturing tolerances can be chosen for their relative positioning, thus simplifying manufacturing.

[0020] In its intended use, the switching unit is used to conduct, for example, an alternating current, but particularly preferably a direct current. In other words, when the electrical current is conducted, it flows in only one direction and / or a possible voltage source provides, in particular, a direct voltage. The electrical voltage is, for example, greater than 30 V and is, in particular, 48 V. Suitably, the electrical voltage is less than 1500 V or less than 800 V. Preferably, the electrical voltage is 830 V or 650 V, 380 V, 96 V or 48 V. For example, the switching unit is used in the electrical system of a motor vehicle, such as a passenger car (car) or commercial vehicle, such as a lorry (truck) or bus. Alternatively, the motor vehicle is, for example, a construction machine or an agricultural device.In a further embodiment, the motor vehicle is a ship, boat or aircraft such as an airplane. Alternatively, the switching unit, when used as intended, in particular if the applied electrical voltage is greater than 100 V, is a component of a system such as a communications system, a data center or an industrial plant. In a further alternative, the system is a component of a DC domestic installation or a DC-supplied lighting device. For example, the switching unit is a component of an automatic line switch or its automatic circuit breaker. The switching unit is suitable, in particular provided and configured for this purpose. For example, the switching unit is provided as a switch, by means of which in particular an operation, i.e. switching on / off, of an electrical circuit takes place.

[0021] For example, the two side surfaces are shaped differently from each other. This makes it particularly possible to achieve a specific concentration of magnetic field lines. However, it is particularly preferred that the two side surfaces be congruent with each other. In other words, the two side surfaces are projected perpendicular to their extension. This provides a comparatively homogeneous magnetic field. Furthermore, it is possible to use identical parts.

[0022] For example, the drive element is arranged outside the arcing chamber. However, the arcing chamber particularly preferably has a compartment in which the drive element is arranged. The drive element is thus stabilized by the arcing chamber, which further increases robustness. In addition, it is possible to manufacture the arcing chamber separately from the drive element, which is then mounted by inserting it into the compartment. This makes it possible to select different drive elements for different applications, for example for use with alternating voltage or direct voltage, while leaving the other components the same, which simplifies production. In other words, by selecting a suitable drive element, the switching unit is adapted to the respective area of ​​application. Alternatively, for example, the drive element can be overmolded using a material from which the arcing chamber is made, particularly in plastic.This ensures a secure connection of the drive element, which increases robustness.

[0023] For example, the arcing chamber is a single piece or comprises multiple components. However, it is particularly preferred that the arcing chamber comprises two shells joined together, which are designed, for example, like housing shells. It is possible to manufacture the two shells separately. During assembly, the arcing element, the fixed contact, and the moving contact, for example, are arranged in one of the shells, and the remaining shell is subsequently joined. This simplifies production while still achieving a comparatively high level of robustness.

[0024] In particular, each of the shells is made of a plastic, preferably using an injection molding process. For example, the extinguishing chamber comprises additional components, but particularly preferably, the extinguishing chamber is formed solely by the two shells. The shells, in particular the dividing plane of the shells, are preferably arranged parallel to the side surfaces, which simplifies production. For example, the two shells are constructed as mirror images of each other, particularly with the exception of any fastening elements.

[0025] For example, the side surfaces are spaced apart from the arcing chamber. However, it is particularly preferred that one of the side surfaces rests against each of the shells. Each shell expediently has a receptacle for the respective side surface. A clearance fit is expediently formed between each receptacle and the associated side surface, which facilitates assembly.

[0026] To join the shells together, for example, they are materially bonded to one another or, if appropriate, corresponding contours engage with one another. In other words, the two shells are inserted into one another to create an arc chamber. For example, the joining is carried out using an additional fastening means, such as a screw, adhesive, or welding. Particularly preferably, the two shells are joined together using the driving element, at least during assembly. The driving element acts in particular on the two side surfaces, causing them to attract one another magnetically. As a result, the two shells are pressed together, stabilizing them relative to one another. This simplifies production. For example, no additional fastening is required. Particularly preferably, the shells are additionally fastened to one another, which increases robustness.In summary, the extinguishing chamber in particular is expediently made of a plastic, to which the two side surfaces, which are expediently made of a metal, are attached on the outside.

[0027] For example, the busbar is only partially inserted into the arcing chamber or only protrudes into the arcing chamber at one end. Alternatively, the arcing chamber is delimited on one side by the busbar. Preferably, the busbar is fastened to the arcing chamber. In particular, the second leg is fastened to the arcing chamber, and the first leg is arranged within the arcing chamber. Preferably, a module is thus provided which has the arcing chamber, the busbar with the fixed contact connected to it, and the arcing element. These are in particular stabilized relative to one another, and to provide the switching unit it is only necessary to arrange the moving contact, which is done in particular by means of any mechanism. In particular, the arcing chamber has a corresponding opening into which the moving contact is inserted.The opening is expediently designed to allow unhindered movement of the moving contact relative to the fixed contact. For example, the mechanism is attached to the outside of the arcing chamber, thus creating the switching unit. This simplifies manufacturing. It is also possible, for example, to use different mechanisms, although the module is essentially always the same. Expediently, the module also includes the drive element, and / or the arcing chamber contains the compartment for the drive element.

[0028] In its intended state, the module is a component of a switching unit and is suitable, in particular provided and configured, for this purpose. The switching unit comprises a fixed contact and a moving contact movably mounted thereon, as well as an extinguishing element, which are arranged in an extinguishing chamber. The fixed contact is connected to a first leg of a busbar that is at least partially U-shaped and therefore has a second leg. Furthermore, the switching unit has a U-shaped magnetic circuit for driving an arc formed between the fixed contact and the moving contact into the extinguishing element, wherein the magnetic circuit has a driving element arranged between the first leg and the second leg, which is perpendicular to two mutually parallel side surfaces of the magnetic circuit, wherein the extinguishing chamber is arranged between the two side surfaces.The module comprises the arcing chamber and the busbar attached thereto, with the fixed contact being connected to the busbar. The arcing element is arranged in the arcing chamber and, in particular, is attached there. The module further comprises the drive element, which is arranged, for example, in a compartment of the arcing chamber. Suitably, the module also comprises the further components of the U-shaped magnetic circuit, in particular the two side surfaces, which are expediently attached to the outside of the arcing chamber. Furthermore, the arcing chamber suitably has an opening for inserting the moving contact. This enables subsequent arrangement of the moving contact in the arcing chamber, and the module can be used essentially unchanged to manufacture the switching unit.

[0029] The circuit breaker serves, in particular, to safeguard, i.e., protect, an electrical line and / or a component, such as a device. In other words, the circuit breaker is a miniature circuit breaker or a device circuit breaker. The circuit breaker has a switching unit. The switching unit comprises a fixed contact and a movable contact mounted relative thereto, as well as an arc quenching element, which are arranged in an arc quenching chamber. The fixed contact is connected to a first leg of a busbar that is at least partially U-shaped and therefore has a second leg.Furthermore, the switching unit has a U-shaped magnetic circuit for driving an arc formed between the fixed contact and the moving contact into the quenching element, wherein the magnetic circuit has a driving element arranged between the first leg and the second leg, which is perpendicular to two mutually parallel side surfaces of the magnetic circuit, wherein the quenching chamber is arranged between the two side surfaces.

[0030] The circuit breaker further comprises a switch lock, by means of which in particular any mechanism is provided. The moving contact is a component of the switch lock. Expediently, the switch lock comprises a latch, by means of which the moving contact is held in a specific position. In particular, the moving contact rests against the fixed contact. Suitably, the switch lock comprises a further latch, by means of which the moving contact is held in place if the moving contact is spaced from the fixed contact. This prevents the moving contact from unintentionally approaching the fixed contact, which would lead to the circuit breaker conducting current again. This increases safety. In particular, the switch lock comprises an element for exerting force on the moving contact, wherein the force is directed away from the fixed contact.Due to the latching mechanism, the direct mechanical contact between the moving contact and the fixed contact is ensured as long as it is engaged. The circuit breaker also includes a release mechanism that is electrically connected in series with the moving contact. Thus, if the moving contact is in contact with the fixed contact, the electrical current is also conducted via the release mechanism. In particular, the release mechanism monitors the electrical current conducted by the circuit breaker. If the electrical current fulfills a certain condition, the release mechanism is triggered, and this trigger mechanism is expediently actuated. This interrupts the flow of current through the circuit breaker.

[0031] In particular, the circuit breaker has a control input that is interconnected with the release and / or other components of the circuit breaker in such a way that, upon application of a specific electrical signal, the switch lock and / or release can be reset and / or actuated. This enables remote commissioning and decommissioning, which increases convenience.

[0032] In particular, the circuit breaker comprises a hand lever, such as a toggle lever, by means of which it is possible to operate the switch lock and / or the release. For example, the hand lever is used to operate the switching unit, placing it either in the electrically conductive state or in the electrically non-conductive state. For example, the release and / or any latching mechanism is operated by the hand lever, separating the moving contact from the fixed contact.

[0033] For example, the circuit breaker is designed as a single-pole device. Alternatively, the circuit breaker is designed as a multi-pole device, in particular a double-pole device. Thus, the circuit breaker comprises two switching units, preferably each with an associated release and / or switch lock. When one of the releases or at least one of the switching units is actuated, the other is also actuated. This enables a comparatively safe disconnection by means of the circuit breaker.

[0034] For example, the trigger is a bimetallic snap-action disc. However, the trigger is particularly preferred. Thus, a magnetic field is created by the trigger when an electric current is applied. Only when the created magnetic field exceeds a certain threshold is any latch released, separating the moving contact from the fixed contact.

[0035] In particular, a hydraulic system is surrounded by an electrical coil, which, for example, creates damping, thereby delaying the triggering. At the very least, however, the trigger is designed to be hydraulic-magnetic. Consequently, a delay in the triggering can be adjusted using the hydraulic system. Alternatively, the trigger can be designed to be thermal-magnetic, for example. This consists of a bimetallic element and an electrical coil. The bimetallic element is triggered in the event of an overload, thus actuating the switching unit. The electrical coil, on the other hand, releases the switching mechanism when a short-circuit current is present, thereby achieving a comparatively rapid separation.

[0036] For example, the circuit breaker is essentially formed solely by the switching unit, the switch mechanism, and the release, which are arranged, for example, within a corresponding circuit breaker housing. Alternatively, the circuit breaker also comprises further components, such as, in particular, a fuse. This is expediently connected electrically in series with the moving contact. The fuse is, for example, a safety fuse. In particular, a characteristic curve of the fuse is designed such that it triggers in the event of overcurrents, thereby interrupting the flow of electrical current. The switching unit, on the other hand, is used in particular for the deliberate switching of an electrical current, i.e., at a rated current, and / or in the event of an overload.

[0037] The circuit breaker suitably comprises an electrical circuit by means of which the state of the fuse is monitored. The circuit is in particular such that a signal is emitted when the fuse is not electrically conductive. For example, a corresponding level (in particular an electrical voltage) is applied to a corresponding terminal of the circuit breaker, to which, for example, a corresponding signal line is connected in the assembled state. Alternatively or in combination with this, the circuit breaker has, for example, a signaling device, such as a light source, in particular an LED, which is incorporated, for example, in the circuit breaker housing. In particular, the signaling device is operated when the fuse is not electrically conductive.This makes it possible to determine from outside the circuit breaker whether the fuse has blown, meaning that replacing the fuse is necessary to restart the circuit breaker. This eliminates the need to open the circuit breaker housing, simplifying maintenance.

[0038] For example, the fuse and the switching unit are arranged in two separate circuit breaker housings. However, it is particularly preferred that the fuse and the switching unit be arranged in a common circuit breaker housing, which simplifies installation.

[0039] In particular, the circuit breaker housing has a fuse compartment in which the fuse is located. The fuse compartment is accessible from outside the circuit breaker housing. This allows the fuse to be replaced from outside without opening the circuit breaker housing. Consequently, maintenance is simplified. The fuse compartment is expediently covered by a lid to prevent the ingress of foreign particles. This also provides protection against accidental contact. In particular, the lid is pivotably mounted on the circuit breaker housing.

[0040] Suitably, the circuit breaker comprises an auxiliary mechanism associated with the fuse. For example, the fuse is inserted into the auxiliary mechanism and / or the auxiliary mechanism is arranged within the fuse compartment. For example, to insert the fuse, the auxiliary mechanism is at least partially inserted into the fuse compartment.

[0041] The auxiliary mechanism is designed, for example, in such a way that when force is applied to the fuse, the switch lock is activated. If someone pulls on the fuse because it needs to be removed from the fuse compartment, the switch lock is activated first, causing an electric current to flow through the fuse. This increases safety. Alternatively, or in combination with this, the switch lock is activated when the force is applied towards the fuse compartment, i.e., when the fuse needs to be inserted into the fuse compartment. This also ensures that no current is immediately passed through the circuit breaker after the fuse is inserted, which also increases safety.For example, the auxiliary mechanism has a bolt that acts on the switch lock when a force is applied to the fuse. If the switch lock has already been actuated, i.e. in particular is in an electrically non-conductive state and the moving contact is therefore spaced from the fixed contact, no action is carried out by the auxiliary mechanism, so that undisturbed movement of the fuse is possible. Alternatively, or in combination with this, the auxiliary mechanism prevents movement of the fuse when the moving contact is in contact with the fixed contact. In summary, the auxiliary mechanism ensures that the fuse can only be replaced in a potential-free state, which increases safety.

[0042] The invention further relates to a motor vehicle. The motor vehicle is, for example, a land-based vehicle and, for example, a passenger car. However, the motor vehicle is particularly preferably a commercial vehicle, such as a bus or, more preferably, a truck. The motor vehicle has a high-voltage electrical system, by means of which, in particular, a direct voltage between 400 V and 800 V is carried. Furthermore, the motor vehicle comprises a low-voltage electrical system, by means of which, expediently, a direct voltage of 12 V, 24 V, or 48 V is carried. The low-voltage electrical system serves, in particular, to supply power to auxiliary units of the motor vehicle, by means of which, for example, comfort functions or the like are provided. The high-voltage electrical system serves, in particular, to supply power to a main drive, which expediently has an electric motor.In this case, the main drive is preferably electrically connected to a high-voltage battery via the high-voltage electrical system, which supplies the high-voltage electrical system. The low-voltage electrical system is supplied, for example, via a transformer from the high-voltage electrical system or via a separate battery. The motor vehicle includes a circuit breaker. The circuit breaker is expediently located electrically between the high-voltage battery and the main drive. Furthermore, the invention also relates to the use of such a circuit breaker for protecting a high-voltage electrical system of a motor vehicle.

[0043] The further developments and advantages explained in connection with the switching unit are also to be transferred analogously to the module / the circuit breaker / the motor vehicle / the use as well as to each other and vice versa.

[0044] In the following, exemplary embodiments of the invention are explained in more detail with reference to a drawing. In the drawings:

[0045] Fig. 1 schematically shows a circuit with a circuit breaker,

[0046] Fig. 2 perspective view of the circuit breaker,

[0047] Fig. 3, 4 show in perspective and in plan view the circuit breaker having a module, with part of a circuit breaker housing omitted,

[0048] Fig. 5 shows a sectional view of the circuit breaker,

[0049] Fig. 6 shows in perspective the module which has an extinguishing chamber,

[0050] Fig. 7 shows the module in perspective, with the extinguishing chamber omitted,

[0051] Fig. 8 perspective view of an extinguishing element of the extinguishing chamber,

[0052] Fig. 9 - 11 perspective alternative designs of the extinguishing element, and

[0053] Fig. 12, 13 according to Fig. 4 and Fig. 5 respectively, a further development of the circuit breaker.

[0054] Corresponding parts are provided with the same reference numerals in all figures.

[0055] Figure 1 shows an electrical circuit 2 having a DC voltage source 4. The DC voltage source 4 is electrically connected to a load 6, so that the load 6 is energized by means of the DC voltage source 4. A circuit breaker 8 is electrically connected between the DC voltage source 4 and the load 6, so that the electrical current conducted between the DC voltage source 4 and the load 6 is conducted via the circuit breaker 8. The circuit breaker 8, which is shown in perspective in Figure 2, has a two-pole design. In other words, it is possible to electrically separate the two electrical potentials of the DC voltage source 4 from the load 6 by means of the circuit breaker 8. For this purpose, the circuit breaker 8 has two switching units 10, with one of the switching units 10 being assigned to each of the electrical potentials.The two switching units 10 are mechanically coupled to each other, so that when one of the two switching units 10 is actuated, the other switching unit 10 is also actuated. Each switching unit 10 is assigned a hand lever 12 that protrudes from a circuit breaker housing 14, so that the respective switching unit 10 can be actuated manually from outside the circuit breaker housing 14. The circuit breaker housing 14, made of plastic, is designed for mounting on a top-hat rail 16.

[0056] Figure 3 shows a perspective view of one of the two switching units 10 arranged in the circuit breaker housing 14, and Figure 4 shows a top view of one of the two switching units 10 arranged in the circuit breaker housing 14, with a portion of the circuit breaker housing 14 removed. Figure 5 shows a sectional view of the corresponding switching unit 10. The switching unit 10 has a first terminal 18, which is located in a corresponding opening in the circuit breaker housing 14. The first terminal 18 serves to receive and secure a cable (not shown in detail) of the circuit 2.

[0057] The first terminal 18 is electrically connected to a trigger 20, which has an electrical coil 22 and a hydraulic reservoir (not shown in detail). The trigger 20 is thus designed as a hydraulic-magnetic device. The first terminal 18 is electrically connected to a moving contact 24 via the trigger 20. The trigger 20 is thus electrically connected in series with the moving contact 24, which is arranged at the end on a pivotably mounted contact bridge 26. The moving contact 24 and the contact bridge 26 are components of a switching mechanism 28, which has a latch (not shown in detail) and a mechanical spring, by means of which the contact bridge 26 is acted upon. The latch makes it possible to hold the contact bridge 26 in a specific position, even though the spring force acts on the contact bridge 26.The latch can be released using the release 20, so that the contact bridge 26 is moved due to the acting spring force. It is also possible to release the latch using the hand lever 12, so that the contact bridge 26 is subsequently pivoted. It is also possible to use the hand lever 12 to move the contact bridge 26 back to its original position and actuate the latch, so that the contact bridge 26 is again in the specified position until the latch is released.

[0058] By means of the contact bridge 26 and the other components of the switch mechanism 28, the moving contact 24 is movably mounted relative to the circuit breaker housing 14 and also relative to a fixed contact 30. The switch mechanism 28 and thus the switching unit 10 are designed such that the moving contact 24 can be moved such that it mechanically contacts the fixed contact 30. When this is the case, the latch engages, so that the moving contact 24 remains mechanically contacted by the fixed contact 30 until the latch is released. As soon as the latch is released, the acting spring force moves the moving contact 24 away from the fixed contact 30.

[0059] The fixed contact 30 is connected to a first leg 32 of a U-shaped busbar 34 made of copper. The busbar is thus bent back on itself, forming a second leg 36. The fixed contact is located on the side of the first leg 32 opposite the second leg 36. The second leg 36 is longer than the first leg 32 and extends to a second terminal 38, which is arranged in a corresponding opening in the circuit breaker housing 14. In the assembled state, another cable of the circuit 2 is attached to the second terminal 38 and electrically connected thereto. Thus, with a suitable adjustment of the switching unit 10, namely when the moving contact 24 is in direct mechanical contact with the fixed contact 30, the two terminals 18, 38 are connected to one another with low resistance, allowing an electrical current to flow between them.If, however, the switching unit 10 is actuated, namely opened, and thus the moving contact 24 is spaced from the fixed contact 30, the two terminals 18, 38 are galvanically isolated from each other. In summary, the circuit breaker 8 comprises the switching unit 10, with the moving contact 24 being a component of the switching mechanism 28 and electrically connected in series with a trigger 20. The other components of the switching mechanism 28 and the trigger 20 are, in particular, not components of the switching unit 10.

[0060] The busbar 34 is a component of a module 40, which is shown in perspective in Figure 6. The module 40 has an arcing chamber 42 comprising two shells 44 joined together. The shells 44 are mirror images of each other and are made of a plastic, namely PBT. The separation plane of the two shells 44, i.e. the plane along which they are joined together, is perpendicular to the pivot axis of the contact bridge 26. Each of the shells 44 has a receptacle 46 on the outside, in which a side surface 48 is inserted. The side surfaces 48 are arranged parallel to the separation plane and are mirror images of each other and therefore congruent with each other. The side surfaces 48 are structurally identical to each other and made of a ferromagnetic material, namely an iron sheet.

[0061] The busbar 34 extends into the arcing chamber 42 and is fastened thereto. For this purpose, the busbar 34 is held in corresponding receptacles or guides (not shown in detail) of the two shells 44. When the two shells 44 are joined together, the busbar 34 is fastened to the arcing chamber 42. In one further development, for example, an adhesive is also used to fasten the busbar 34 in the two shells 44. In a further alternative, the adhesive by means of which the busbar 34 is fastened to the two shells 44 is used to join the two shells 44 together. In summary, the busbar 34 is fastened to the arcing chamber 42.

[0062] The fixed contact 30 is located within the arcing chamber 42. The arcing chamber 42 has an opening 50 through which the moving contact 24 can be inserted into the arcing chamber 42 during assembly, so that it is also located within the arcing chamber 42 when assembled. The opening 50 is designed to allow unhindered movement of the contact bridge 26. However, the opening 50 is not larger than necessary, so that the arcing chamber 42 is otherwise closed. The arcing chamber 42 has a compartment 52 covered by the side surfaces 48, within which a driving element 54 is arranged. If the circuit 2 carries a direct voltage, the driving element 54 is a permanent magnet. If an alternating voltage is carried via the circuit 2, the driving element 54 is made of steel.The compartment 52 is provided in the plastic of the two shells 44, and there is, for example, a press fit or a clearance fit between the drive element 54 and the shells 44. The 54 is, for example, mounted in the compartment 52 when the two shells 44 are joined together, or alternatively, for production, for example, the drive element 54 is already inserted into the part of the compartment 52 that one of the two shells 44 has, and the other shell 44 is subsequently joined, with the drive element 54 being inserted into the other part of the compartment 52.

[0063] Figure 7 also shows the module 40 in perspective, but the arcing chamber 42 is not shown. One of the two side surfaces 48 is also not shown. The drive element 54 rests against the opposite side surfaces 48 at its ends, forming a U-shaped magnetic circuit 56. In other words, the magnetic circuit 56 comprises the drive element 54 and the two side surfaces 48. The drive element 54 and thus also the compartment 52 are arranged between the two legs 32, 36 of the busbar 36. If the circuit 2 carries an alternating voltage, the induction of a magnetic field into the drive element 54 is improved.

[0064] The magnetic field provided by the drive element 54 is thus deflected by the two side surfaces 48 and emerges perpendicularly from these, creating a magnetic field directed parallel to the drive element 54, which penetrates the arcing chamber 42. If the drive element 54 is designed as a permanent magnet, the two side surfaces 48 are attracted to the drive element 54 due to the acting magnetic forces, so that the shells 44 arranged therebetween are pressed against one another, which increases the stability of the module 40. In summary, the magnetic circuit 56 thus has the drive element 54 arranged between the first leg 32 and the second leg 36, which is perpendicular to the two mutually parallel side surfaces 48 of the U-shaped magnetic circuit 56. The arcing chamber 42 is arranged between the two side surfaces 48.The module 40 further comprises an extinguishing element 58, which is arranged within the extinguishing chamber 42. The extinguishing element 58 is located in corresponding internal receptacles of the two shells 44 and is stabilized there.

[0065] The quenching element 58 is shown in perspective in Figure 8 and has a plurality of wedge-shaped, stacked quenching strips 60, between which a meandering gap (not shown in detail) is formed. The quenching strips 60 are made of a ceramic that is not electrically conductive. The quenching strips 60, i.e., the wedges, are identical parts that are arranged in different orientations, forming a substantially V-shaped notch that points toward the fixed contact 30 and the moving contact 24. The quenching strips 60 also have interlocking structures, which provide intrinsic stability to the quenching element 58.

[0066] Figure 9 shows an alternative embodiment of the quenching element 58. In this embodiment, the thickness of the quenching strips 60 is reduced, and these partially have different shapes. The quenching strips 60 are also made of ceramic, and between them, in some sections, a V-shaped notch is also formed, which is directed toward the two contacts 24, 30. A meandering gap (not shown in detail) is also present.

[0067] Figure 10 shows a further alternative of the extinguishing element 58, which has the stacked extinguishing strips 60. However, these are made of metal and spaced apart by spacers (not shown in detail).

[0068] Figure 11 shows a further embodiment of the extinguishing element 58. This element has two opposing holders 62 made of a ceramic or plastic material, into which the extinguishing strips 60 are inserted and by means of which they are held. The extinguishing strips 60 are made of metal and spaced apart from one another by the two holders 62. During normal operation of the circuit breaker 8, an electrical current is conducted between the two terminals 18, 38. If the hand lever 12 is actuated or the release 20 is triggered, the switching unit 10 is actuated and thus opened. Thus, the moving contact 24, which until then was in contact with the fixed contact 30, is spaced apart from it.If the electrical voltage provided by the circuit 2 is sufficiently high, it is possible that the air present between the contacts 24, 30 is ionized, causing an arc to form, which is why an electrical current flows between the two connections 18, 28. In this case, the arc represents an electrical conductor. The fact that the quenching chamber 42 is penetrated by the magnetic field via the magnetic circuit 56 means that the Lorentz force acts on the arc, due to which the arc is moved towards the quenching element 58 and partially bulges out. In the process, part of the arc is partially moved into the quenching element 58. The bulging alone increases the length of the arc, which is why the electrical voltage required to maintain it increases.As soon as the arc enters the quenching element 58, further deformation occurs, and depending on the quenching element 58 used, it is possible for the arc to split into several individual (partial) arcs. The arc is also cooled by the quenching element 58. All of this leads to a further increase in the electrical voltage required to maintain the arc. If this voltage is greater than the electrical voltage present between the two terminals 18, 28, the arc collapses, and the electrical current flow between the two terminals 18, 28 is safely interrupted. Galvanic isolation is ensured by the moving contact 24, which is spaced apart from the fixed contact 30.

[0069] Thus, the magnetic circuit 56 serves to drive the arc formed between the fixed contact 30 and the moving contact 24 into the quenching element 58 when the arc is present. As long as the arc is present, it is enclosed by the quenching chamber 42, thus preventing electrical contact between other components of the circuit breaker 8 and the arc. The quenching chamber 42 also provides thermal insulation, thus reducing stress on the other components of the circuit breaker 8.

[0070] Figures 12 and 13 show a further development of the circuit breaker 8, corresponding to Figures 4 and 5, wherein the switching unit 10 remains unchanged. The circuit breaker housing 14, the hand lever 12, and the two terminals 18, 38 are also present. The switch lock 28 is also present. The circuit breaker 8 has the release 20, which, however, is merely designed as a bimetallic snap-action disk, so that the circuit breaker 8 is a thermal circuit breaker. In a variant not shown in detail, the electrical coil is still present, so that the release 20 is thermally magnetic. In a variant not shown in detail, no release is present, and the circuit breaker 8 is operated by remote release or solely using the hand lever 12.

[0071] The circuit breaker housing 14 has a fuse compartment 64, within which a fuse 66 in the form of a melting fuse is arranged. Electrically, the fuse 66 is arranged between the moving contact 24 and the first terminal 18. In other words, the fuse 66 is electrically connected in series with the moving contact 34, so that the electrical current conducted between the two terminals 18, 38 is also conducted via the fuse 66.

[0072] The fuse compartment 64 ends on the outside of the circuit breaker housing 14 and is closed on the outside by a cover 68 pivotally mounted on the circuit breaker housing 14. The fuse compartment 64 is thus accessible from outside the circuit breaker housing 14, namely by removing the cover. The cover 68 is a component of an auxiliary mechanism 70, which is actuated by the hand lever 12. When the hand lever 12 is in a specific position, the auxiliary mechanism 70 prevents the cover 68 from pivoting, thereby releasing the fuse compartment 64. This occurs when the position of the hand lever 12 corresponds to the open switching unit 10, i.e., when the moving contact 24 is in contact with the fixed contact 30. Since the fuse compartment 64 is closed by the cover 68, there is no room for movement for the fuse 66.Thus, the auxiliary mechanism 70 is designed such that when the moving contact 24 rests against the fixed contact 30, movement of the fuse 66 is prevented.

[0073] Should a malfunction occur or should the hand lever 12 be moved with the cover 68 open such that the moving contact 24 rests against the fixed contact 30, the auxiliary mechanism 70 will actuate the hand lever 12 upon application of force to the fuse 66, for example, upon attempting to remove it from the fuse compartment 64 or attempting to insert it into the fuse compartment 64, so that the switching lock 28 is actuated and thus the moving contact 24 is spaced from the fixed contact 30. In other words, the switching unit 10 is actuated. Thus, only a potential-free removal or insertion of the fuse 66 is possible.

[0074] A circuit (not shown in detail) is also provided for monitoring the condition of the fuse 66. If the fuse is electrically non-conductive, particularly because it is damaged or blown, a signaling device arranged on the outside of the circuit breaker housing 14, namely an LED (not shown in detail), is activated, so that it is visible from outside the circuit breaker housing 14 that the fuse 66 is no longer suitable for conducting electrical current.

[0075] The invention is not limited to the exemplary embodiments described above. Rather, other variants of the invention can also be derived therefrom by those skilled in the art without departing from the subject matter of the invention. In particular, all 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.

[0076] 25

[0077] REPLACEMENT SHEET (RULE 26) List of reference symbols

[0078] 2 circuits

[0079] 4 DC voltage source

[0080] 6 Last

[0081] 8 circuit breakers

[0082] 10 Switching unit

[0083] 12 hand levers

[0084] 14 Circuit breaker housing

[0085] 16 DIN rail

[0086] 18 first connection

[0087] 20 triggers

[0088] 22 electrical coil

[0089] 24 moving contact

[0090] 26 Contact bridge

[0091] 28 Switch lock

[0092] 30 fixed contact

[0093] 32 first leg

[0094] 34 Busbar

[0095] 36 second leg

[0096] 38 second connection

[0097] 40 Module

[0098] 42 Extinguishing chamber

[0099] 44 bowl

[0100] 46 recording

[0101] 48 side surface

[0102] 50 opening

[0103] 52 compartments

[0104] 54 Driving element

[0105] 56 magnetic circuit

[0106] 58 extinguishing element

[0107] 60 fire extinguishing strips

[0108] 62 holders

[0109] 64 Fuse compartment fuse cover auxiliary mechanism

Claims

Claims 1. Switching unit (10) with a fixed contact (30) and with a moving contact (24) movably mounted therewith, as well as with an extinguishing element (58), which are arranged in an extinguishing chamber (42), wherein the fixed contact (30) is connected to a first leg (32) of a busbar (34) which is at least partially U-shaped and therefore has a second leg (36), and with a U-shaped magnetic circuit (56) for driving an arc formed between the fixed contact (30) and the moving contact (24) into the extinguishing element (58), wherein the magnetic circuit (56) has a driving element (54) arranged between the first leg (32) and the second leg (36), which is perpendicular to two mutually parallel side surfaces (48) of the magnetic circuit (56), and wherein the extinguishing chamber (42) is arranged between the two side surfaces (48).

2. Switching unit (10) according to claim 1, characterized in that the two side surfaces (48) are congruent with each other.

3. Switching unit (10) according to claim 1 or 2, characterized in that the arcing chamber (42) has a compartment (52) in which the drive element (54) is arranged.

4. Switching unit (10) according to one of claims 1 to 3, characterized in that the arcing chamber (42) has two shells (44) joined to one another, against each of which one of the side surfaces (48) rests on the outside.

5. Switching unit (10) according to one of claims 1 to 4, characterized in that the busbar (34) is fastened to the arcing chamber (42).

6. Module (40) of a switching unit (10) according to claim 5, which comprises the quenching chamber (42) with the busbar (34) attached thereto, to which the fixed contact (30) is connected, and the drive element (54), wherein the quenching element (58) is arranged in the quenching chamber (42), and wherein the quenching chamber (42) has an opening (50) for inserting the moving contact (24).

7. Circuit breaker (8) with a switching unit (10) according to one of claims 1 to 5, wherein the moving contact (24) is a component of a switching lock (28) and is electrically connected in series with a trigger (20).

8. Circuit breaker (8) according to claim 7, characterized in that the trigger (20) is hydraulic-magnetic or thermal-magnetic.

9. Circuit breaker (8) according to claim 7 or 8, characterized in that a fuse (66) is electrically connected in series with the moving contact (24).

10. Circuit breaker (8) according to claim 8, characterized in that the fuse (66) is arranged in a fuse compartment (64) of a circuit breaker housing (14), wherein the fuse compartment (64) is accessible from outside the circuit breaker housing (14).

11. Circuit breaker (8) according to claim 10, characterized in that the fuse (66) is assigned an auxiliary mechanism (70) which is designed such that when a force is applied to the fuse (66), the switching lock (28) is actuated, and / or that a movement of the fuse (66) is prevented when the moving contact (24) is in contact with the fixed contact (30).

Images