DE102013005439A1 - Safety device for securing electric current path in electrical system of e.g. hybrid vehicle, has overload relays that are connected with shift element over mechanical coupling for interruption of current paths - Google Patents

Abstract

The safety device serves to protect at least one electrical current path, in particular an electrical system of a motor vehicle, and has an infeed path (4) as the first current path and at least one load path (6) as a further current path. To protect the current paths (4, 6) against an electrical short circuit and against an overcurrent, a short circuit release (8, 18) and an overcurrent release (10A, 10B) are arranged in series, each of which is mechanically coupled to a switching element (12) to interrupt at least one of the current paths (4, 6). In this way, a reliable shutdown of the current paths (4, 6) is achieved if necessary.

Description

The invention relates to a securing device for securing at least one electrical line of a vehicle electrical system of a motor vehicle with the features of claim 1.

For the protection of consumers but especially of electrical lines, for example, within an electrical system of a motor vehicle fuses are generally required. On the one hand, these must reliably trigger both a short-circuit current and an overcurrent (overload) reliably. Overcurrents are understood to be currents from 1.5 to 2 times the respective rated current for which the respective electrical line is formed.

From the DE 20 211 002 884 U1 shows a fuse arrangement, are formed in the fuse elements designed as a fuse directly into a formed as a power distribution element stamping sheet. Such a power distributor serves as a power distributor of an electric power provided by a power source on a plurality of individual consumer strands, hereinafter referred to as load path. This power distributor is the input side connected to the vehicle battery typically via a feed path.

From the EP 1 155 919 B1 is to take an electrical system of a motor vehicle with two voltage levels, each voltage level is protected by a fuse element. In order to detect a short circuit between the two voltage levels, a voltage comparator is provided, which in the event of a short circuit activates an electronic switch for disconnecting a current path as a switching element.

Proceeding from this, the invention has the object, especially in an electrical system of a motor vehicle in case of need to ensure a reliable shutdown of a current path.

The object is achieved according to the invention by a safety device with the features of claim 1. This generally serves to hedge at least one electrical line of a vehicle electrical system in a motor vehicle and includes a feed path as a first current path and at least one, preferably a plurality of load paths as further current paths. The feed path can be connected to a power source, in particular a battery, and also connected when installed. When installed, the various load paths are each connected to load load circuits. To protect against an electrical short circuit as well as against an overload, both a short-circuit release and a series-connected thereto overload release is arranged, which is connected in each case via a mechanical coupling to a switching element for interrupting at least one of the current paths.

About the series connection of the two tripping elements in the respective current path reliable triggering and disconnecting the current path is ensured even for different overload cases, namely both short circuits with extremely high currents as well as overcurrents, only in the range of for example 1.5 to 3 times the rated current. The triggers themselves are not designed as separating elements, but are connected via the mechanical coupling with a switching element in connection, which is therefore actuated mechanically in the triggering case with the help of the respective trigger. As a result, there is also a spatial separation between the triggering element and the separating or switching element. The two triggers are designed in particular as purely passively acting elements, which are integrated directly into the current path and thus current flowing through in the operating case. For triggering, therefore, no active control is required. This takes place in a purely passive way.

The securing device is preferably integrated in a power distributor, which has on the input side the feed path and on the output side a plurality of load paths. The power distributor preferably comprises a power distribution rail designed as a stamped sheet metal, which has a plurality of outgoing straps for forming the load paths. The integration into the power distributor itself is a compact, integrated design achieved and the arrangement of additional security elements is not required. Such a power distributor is usually arranged in a so-called Vorsicherungsdose within the motor vehicle, which is directly downstream of a battery of the motor vehicle, and via which the power and power distribution is carried out to different load currents within the motor vehicle. The individual load paths are designed, for example, for rated currents of a few hundred amperes.

According to an expedient embodiment, at least one trigger, in particular the short-circuit release, and preferably both triggers are integrated directly into the feed path. There is therefore a central shutdown of the power supply in the event of triggering.

According to a preferred embodiment, the two triggers are preferably mechanically coupled to the same, common switching element. This is therefore activated by one of the two triggers independently of the other trigger, so that a separation of the current path takes place. The switching element therefore only needs to be formed once, whereby the circuit complexity is kept low. This is particularly advantageous when separating very high currents, since the switching element must be made very robust. The switching element is designed for example as a so-called snap disk.

In order to ensure a reliable separation despite the high switching currents of up to several hundred amperes, the switching element preferably comprises a mechanically biased in the separation direction switching contact. The required separation energy for releasing the switching contacts of the switching element is therefore already stored in particular via a spring element. The separation force for separating the switching contacts therefore need not be exercised via the mechanical coupling. Conveniently, the mechanical coupling is connected to a locking element, which blocks the separation of the biased switching contact in normal operation. In particular, a spring is blocked, so that it does not act on the switching contact in the separating direction. When triggered, therefore, only this locking element needs to be released via the mechanical coupling, so that due to the mechanical bias the switching contacts of the switching element are disconnected. After triggering (switching off), a reset can be made either manually or via an external control.

In addition to the purely passive triggering of the two triggers is at least one and are preferably both triggers also actively controlled to bring about triggering or support. For this purpose, in particular, a control device is provided, which transmits a control signal to a control, which ultimately affects the passive acting trigger so that it triggers and thus actuates the switching element via the mechanical coupling. By this addition, it is possible to provide additional sensors within the electrical system, which for example, in addition to monitor the electrical system in terms of inadmissible operating conditions and, if necessary, transmit a corresponding trigger signal to the controller. In particular, with only slight overcurrents, this is advantageous in order to accelerate triggering of the overcurrent release and thus to avoid line damage.

The short-circuit release has according to an expedient embodiment, a trip coil, which is incorporated into one of the current paths, in particular in the feed path and current flows through during operation. Furthermore, a movable armature is arranged in the interior of the tripping coil, which is deflected in the event of a short circuit, that is to say in the case of a short-term, marked change in the current in the current path. The armature itself is in turn connected via a mechanical coupling element to the switch for forming the mechanical coupling in conjunction to trigger this. As a result, proven, passive standard components are used to detect a short-circuit current.

For active short-circuit tripping, there is the possibility of controlling this trip coil via an inductive coupling via another coil. In a preferred embodiment, however, preferably additionally arranged an actively controllable short-circuit release. This is preferably also connected via a mechanical coupling with the switching element. In particular, it has the same triggering mechanism as the passive short-circuit release and, like this, in particular comprises a control coil with armature, which is mechanically connected to the switching element (FIG. 12 ) is coupled.

The overcurrent release is expediently designed as a thermal release, which causes passive due to the occurring in an overcurrent heating of the electrical line. Conveniently, for this purpose, a bimetal is incorporated in the current path, which in turn is also connected via a coupling element mechanically to form the mechanical coupling with the switching element. This bimetal is preferably fixed, so inseparably involved in the current path. The current path via the trigger, ie via the bimetal, thus remains even in the event of tripping. The separation of the current path takes place exclusively via the switching element arranged separately for the thermal tripping element.

In a preferred development, further thermal triggers are integrated in at least one and preferably in all load paths in addition to the triggers preferably arranged in the feed path. As a result, a reliable individual protection of a respective load path against overcurrents can be ensured.

Conveniently, some, preferably all of the other thermal triggers are each mechanically coupled to the switching element. In addition to the thermal trigger in the feed path, the switching element can therefore be switched off via each of the individual further thermal triggers in the individual load paths. If an error occurs in one of the load paths, therefore, a central shutdown via the common switching element takes place.

In an alternative embodiment, only the individual load path is separated via the further thermal triggers. For this purpose, the further thermal releases themselves are preferably designed as switching elements. The thermal releases are in this case designed in particular as a bimetal, which itself has a switching contact for disconnecting the current path at a movable end. The switching element can also be designed as a so-called snap disk.

At least one, preferably several or all of the thermal triggers are each assigned a drivable heating element for the purpose of triggering. The bimetal can therefore be heated via the heating element, thus bringing about the tripping function. This also allows active control of the otherwise passive triggering element.

Due to the high currents to be switched, there is the danger that an arc results when the contacts of the switching element are disconnected. Conveniently, therefore, the switching element, preferably each switching element, each associated with a device referred to as a spark extinguishing path for deleting such arcs. In particular, this applies to the switching element which is coupled to the short-circuit release and the thermal release in the feed path. In addition, such devices are expediently also formed in the form of switching elements thermal triggers in the individual load paths.

To reduce the risk of an arc and in particular to reduce the load on the switching contacts of the switching element, the switching element itself is preferably designed as a multi-pole contact. The individual contact poles are arranged in a series connection, so that a voltage divider is formed. This leads to lower (arc) voltages.

Embodiments of the invention will be explained in more detail with reference to FIGS. These show in simplified representations:

1 a safety device according to a first embodiment, in which a short-circuit release and a thermal release are connected in series in a feed path and further in the load paths further thermal releases are arranged and all triggers are mechanically coupled to a switching element,

2 a safety device according to a second embodiment, in which, in contrast to the variant according to 1 the thermal releases in the load paths are designed as switching elements,

3 a safety device similar 2 , in the example of a thermal release in a load path, the control of the thermal release is illustrated by a heating element.

In the figures, like-acting parts are provided with the same reference numerals.

The safety device shown in the figures is a total of a power distributor shown in dashed lines 2 integrated, which in particular has a distributor housing. The power distributor 2 has input side a feed path 4 as well as several load paths on the output side 6 on. To the entry path 4 is in the installed state, a power source, in particular a vehicle battery connected. To the outgoing load paths 6 each consumer circuits are connected. The safety device is therefore integrated in total in a vehicle electrical system and there in particular in a Vorsicherungsdose in which the power is distributed to the different consumer sub-circuits within the motor vehicle. The vehicle electrical system is a high-voltage on-board network with a voltage of 40 V and above. The feed path 4 and partly also the respective load paths 6 are typically designed for currents of several tens of amps to several hundred amps. The electrical voltage within the electrical system is typically in the range of several tens of volts DC in conventional electrical systems. However, the safety device described here is generally suitable for both DC and AC or mixed voltage networks. In particular, the safety device is also suitable for high-voltage applications, for example in hybrid vehicles with electromotive drive with up to several hundred volts of voltage.

The securing device in each case comprises a tripping coil 8th as a short-circuit release, a first thermal release 10A as an overcurrent release and a switching element 12 , which is to interrupt the Einspeisepfads 4 is trained. The trip coil 8th as well as the first thermal trigger 10 are in series in the feed path 4 switched and are in each case flowed through by the feed stream during operation.

The trip coil 8th is an anchor 14 assigned, which via a mechanical coupling element 16A with the switching element 12 connected is. In addition, in the embodiments additionally a control coil 18 with another anchor 14 provided, which via a second mechanical coupling element 16B also with the switching element 12 connected is. The control coil 18 can be controlled via two control terminals via a control unit, not shown here, by being charged with a coil current.

The thermal trigger 10A is formed as a bimetal, which is fixedly positioned with its one end and the other end is movable under thermal stress. In particular, the movable end is via an elastic connection with the feed path 4 electrically connected permanently and firmly. Even with a deflection of the bimetal at a temperature change, therefore, the electrical connection via the thermal release remains 10A consist.

The thermal trigger 10A is via a third mechanical coupling element 16C also with the switching element 12 mechanical coupled.

In addition to the first thermal release 10A is in each of the load paths 6 another thermal trigger 10B arranged. These are in the embodiment of 1 identical to the first thermal release 10A trained and firm and inseparable respectively in the load path 6 involved. In the embodiment of the 1 is any of the other thermal triggers on the mechanical coupling element 16C with the switching element 12 connected. Alternatively to the common mechanical coupling element 16C is every further thermal trigger 10B assigned its own mechanical coupling element.

In the embodiments of the 2 and 3 are the other thermal triggers 10B In contrast, even as other switching elements 20 trained, the directly the respective load path 6 interrupt in the event of a trip.

The switching element 12 comprises by means of a spring element 22 preloaded switching contacts 24 , The spring tension is oriented in the direction of separation, the spring element 22 therefore serves as energy storage for disconnecting the switch contacts 24 in the case of triggering. The mechanical coupling elements 16A to C acting in each case on a not shown here detent a, which is the spring element 22 holds in the preloaded normal position.

In an alternative embodiment are called switching elements 12 so-called snap discs used, which typically include a curved disc, for example made of spring steel.

The switching element 12 further includes an apparatus for arc extinguishing 26 on. This device is designed in a conventional manner and avoids that when disconnecting the switch contacts 24 Any resulting arc persists for a long time.

The switching element 12 is preferably designed as a two-pole or multi-pole switching contact element, so that therefore several isolation or Abschaltpfade within the single current path 4 are arranged, on which distributes the electrical voltage, whereby the risk of an arc is reduced.

At the in 2 and 3 illustrated embodiments in which the other thermal trigger 10B at the same time as a switching element 24 are formed, each of these switching elements 24 also such a device for arc extinguishing 26 assigned.

In the 3 is an example of one of the other thermal trigger 10B another heating element 28 shown, which is designed for direct heating of the bimetal. The heating element 28 is again controlled in not shown here by means of a control unit via two control terminals. The heating element is, for example, a PTC element or else a heating wire.

The operation of the safety device is as follows:
Normally flows through the trip coil 8th and over the closed switch contacts 24 a feed-in current that goes beyond the individual thermal triggers 10A . 10B on the different load paths 6 is split. In an overload case, two different situations have to be distinguished:
In the case of a short circuit, where the current in the feed path 4 within a short time rises sharply by this change in current in the trip coil 8th a changing magnetic field is generated which acts on the magnetic armature 14 acts and this mechanically offset. This mechanical adjusting movement is via the mechanical coupling element 16A on the switching element 12 transfer. Here, the locking of the prestressed spring element 22 solved, so that the switching contacts 24 be separated and thus the feed path 4 is interrupted. Thus, in the event of a short circuit, a safe central disconnection of the power supply of the individual load paths takes place 6 ,

Such a shutdown can also be with the help of the control coil 18 cause. This forms a second short-circuit release, which is formed in the embodiment according to the same principle as the first by the trip coil 8th with the anchor 14 formed short-circuit release. In contrast to this is the control coil 18 however, for significantly lower currents to effect the dislocation of the anchor 14 formed, so that by significantly lower signal currents, for example already in the lower ampere or milliampere range of anchors 14 is offset and via the mechanical coupling element 16B the switching element 12 is pressed.

In the case of an overcurrent, the separation takes place at least from one of the paths 4 . 6 with the help of one of the thermal release 10A . 10B , The thermal trigger 10A is usually designed for higher currents than the other thermal triggers 10B because over the first thermal trigger 10A the entire current flows.

Generally, an overcurrent leads to heating in the thermal triggers 10A . 10B in the current path 4 . 6 , which leads to a deflection of the respective bimetal. About the mechanical coupling element 16C This thermally induced deflection is again on the switching element 12 transferred so that the switch contacts 24 be opened.

Due to the spring preload, the switching element is in tripping 12 held in the open position. It must therefore be actively reset again to the feed path 4 to close again. A particular advantage of the spring-biased switching element 12 can be seen in the short-term, quick release.

The in the 2 and 3 shown further, as switching elements 20 trained thermal releases 10B work on the same principle as the first thermal release 10A with the difference that a deflection of the bimetal directly to a separation of the other switching contacts 30 the respective switching elements 20 leads. In these, a reversible reset takes place after the tripping event, as soon as the bimetal cools again. The other switching contacts 30 will therefore be closed again. Alternatively, appropriately designed triggers are used for irreversible disconnection 10A . 10B used, for example, the previously mentioned snap discs, then an active reset is required. This can be done manually or via an external control.

With the help of the heating element 28 There is now the possibility to maintain the separation under control by heating the bimetal controlled. Alternatively, it is also possible to actively by heating the respective further switching element 20 the respective load path 6 to separate. Overall, therefore, there is the possibility, in addition to the purely passive triggering of both the switching element 12 as well as the other switching elements 20 each of these also controlled when needed to activate. For this purpose, the aforementioned control device is provided, which is preferably additionally connected to an evaluation and / or sensors that monitor the electrical system for irregularities and, if necessary, just the separation of the individual current paths 4 . 6 prompted if necessary.

The invention has been described with reference to a motor vehicle electrical system, but is also suitable for other applications in general in electrical systems, such as photovoltaics.

LIST OF REFERENCE NUMBERS

2

power cables

4

feeding path

6

load path

8th

trip coil

10A

first thermal trigger

10B

another thermal trigger

12

switching element

14

anchor

16A, B, C

mechanical coupling elements

18

control coil

20

another switching element

22

spring element

24

switching contact

26

Device for arc extinguishing

28

heating element

30

another switching contact

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 20211002884 U1 [0003]
• EP 1155919 B1 [0004]

Claims (15)

Safety device for securing at least one electrical current path ( 14 . 6 ) in particular a vehicle electrical system of a motor vehicle comprising a feed path ( 4 ) as the first current path and at least one load path ( 6 ) as a further current path, characterized in that for protection against an electrical short circuit as well as against an overcurrent a short-circuit release ( 8th . 14 ) and in series an overcurrent release ( 10A , B) are arranged, each via a mechanical coupling with a switching element ( 12 ) for interrupting at least one of the current paths ( 4 . 6 ) are connected. Safety device according to claim 1, characterized in that it is integrated in a power distributor ( 2 ), the input side of the feed path ( 4 ) and on the output side several load paths ( 6 ) having. Safety device according to claim 1 or 2, characterized in that both triggers ( 8th . 14 ; 10A , B) with the same switching element ( 12 ) are coupled. Safety device according to one of the preceding claims, characterized in that the switching element ( 12 ) a switching contact ( 24 ), which is mechanically biased in the separation direction. Safety device according to one of the preceding claims, characterized in that at least one of the triggers ( 10B ) is drivable in addition to a purely passive triggering to cause the triggering. Safety device according to one of the preceding claims, characterized in that the short-circuit release a trip coil ( 8th ) in one of the current paths ( 4 ) and current flows through the operation, and further one of the trip coil ( 8th ) associated anchor ( 14 ), which is deflected in the event of a short circuit and via which the mechanical coupling with the switching element ( 12 ) he follows. Safety device according to one of the preceding claims, characterized in that furthermore a controllable short-circuit release ( 18 . 14 ) is arranged, which via a mechanical coupling with the switching element ( 12 ) and in particular a control coil ( 18 ) with anchor ( 14 ), which mechanically with the switching element ( 12 ) is coupled. Safety device according to one of the preceding claims, characterized in that the overcurrent release ( 10A . 10B ) is a thermal release and for this purpose in the current path ( 4 . 6 ) a bimetal is integrated, which via a coupling element ( 16C ) mechanically with the switching element ( 12 ) connected is. Safety device according to claim 8, characterized in that the thermal release ( 10A . 10B ) inseparably in the current path ( 4 . 6 ) is involved. Securing device according to claim 8 or 9, characterized in that in at least one, preferably all load paths ( 6 ) more thermal releases ( 10B ) are integrated. Safety device according to claim 10, characterized in that the further thermal releases ( 10B ) each mechanically with the switching element ( 12 ) are coupled. Safety device according to claim 10, characterized in that the further thermal releases ( 10B ) itself as further switching elements ( 20 ) are formed. Safety device according to one of claims 8 to 12, characterized in that the thermal release ( 10A . 10B ) to cause the triggering a controllable heating element ( 28 ) assigned. Safety device according to one of the preceding claims, characterized in that the at least one switching element ( 12 . 20 ) a device ( 26 ) for erasing arcs when disconnecting the switching contacts ( 24 ) having. Safety device according to one of the preceding claims, characterized in that the switching element ( 12 ) is designed as a multi-pole contact switch.

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