DE102011014343A1 - Safety device for a power supply of a motor vehicle - Google Patents

Abstract

The application relates to a safety device (1) for a circuit of a motor vehicle, the safety device having a conductor element (2) with a predetermined breaking point (22). The safety device also contains a pyrotechnic safety element (3) with a propellant charge (32) which, when triggered, cuts through the predetermined breaking point (22) of the conductor element. A fuse (23), which cuts through the conductor element (2) when a predetermined temperature is exceeded, is provided in this securing device.

Description

The application relates to a safety device for a power supply of a motor vehicle. In motor vehicles safety devices are used to protect cables from excessive currents. If there is a short circuit in a vehicle, for example due to an accident, a fuse usually ensures that the circuit is interrupted. This interruption is caused by the fact that an electrical conductor in the fuse melts due to the high short-circuit current through this electrical conductor.

The DE 694 14 798 T2 shows a Abschaltsicherungsvorrichtung using a combination of a fuse and a mechanical switch.

The DE 100 49 071 A1 shows a securing device in which both a pyrotechnic fuse and an overcurrent protection are provided in a housing. The pyrotechnic fuse contains a propellant charge, the explosion of a conductor element is severed. At the same time, a restriction in the current-carrying path is provided, which heats up when the current exceeds a predetermined switching threshold. This heating triggers the pyrotechnic fuse. However, the time between the warming in the constriction until the triggering of the propellant charge has to be considered.

The application has for its object to provide a safety device for a circuit in a motor vehicle, in which the interruption of the circuit takes place quickly in critical situations.

This object is solved by the subject matter of the independent claims. Advantageous embodiments emerge from the respective subclaims.

A safety device for a circuit of a motor vehicle is provided, wherein the safety device has a conductor element with a predetermined breaking point. In addition, the securing device includes a pyrotechnic securing element with a propellant charge, which cuts through the predetermined breaking point of the conductor element when triggered. A fuse, which cuts through the conductor element when a predetermined temperature is exceeded by melting, is also provided in the securing device.

With the security device two security concepts are combined. Firstly, cables that are damaged by wear or mechanical impulses are protected by the fuse when the current rises sharply. On the other hand, the pyrotechnic fuse element can be actively triggered, which is useful, for example, in the event of an accident. Especially in the first case in which the cable is broken, for example, because the insulation of a cable is frayed, causing a short circuit, the activation of the fuse takes place quickly.

This means that the increase of the current directly causes a severing of the conductor element. This direct release of the conductor element is safe compared to the separation of the conductor element by the pyrotechnic fuse element, since the control of the pyrotechnic fuse element is more complex than the fuse. The triggering of the pyrotechnic fuse element can be controlled for it. This makes it possible to realize a variety of conditions, for example, to detect an accident. Depending on a combination of these conditions, a pyrotechnic fuse element will be triggered or not.

In one embodiment, the predetermined breaking points and the fuse are connected in series. Due to the separate arrangement of the predetermined breaking point and the switch fuse they can be dimensioned independently of each other, and thus exactly on their particular application.

In contrast, if the fuse also forms the breaking point, a particularly compact design of the securing device is possible, saving space and weight in the vehicle.

If the security device has a housing to which external electrical connections are attached, via which the explosive charge of the pyrotechnic security element can be triggered from outside the housing, it is possible to trigger the pyrotechnic securing element via a simple cable connection to the security device.

The cable can be depending on the type of connection to the external connection z. B. plugged, soldered or clamped.

Preferably, the pyrotechnic element and the fuse are integrated in a housing. This requires only one component, which is inserted into the current path to be protected.

In one embodiment, a control device for triggering the propellant charge of the pyrotechnic fuse element is provided, wherein the control device for receiving and Evaluating a variety of input signals is set up. This is determined by means of a plurality of input signals in the control device, whether the propellant charge to be triggered. For example, a plurality of sensors can be used to detect an accident, wherein it can be determined in the control device which and how many of the sensors must indicate the accident in order to actually trigger the propellant charge of the pyrotechnic fuse element.

In one embodiment, the control device is provided in the same housing as the pyrotechnic securing element. Thus, one need not provide for the control device own housing, which simplifies the assembly in the vehicle as a whole.

In a further embodiment, the conductor element contains a stamped part made of copper, in which particularly the predetermined breaking point is formed. Copper is known for its good conductivity.

There is also provided a vehicle with a presented safety device. In this case, the safety device is connected in the path between a negative pole of a vehicle battery on the one hand and on the other hand, a plurality of first consumers. Thus, the security device serves as a security device for a plurality of first consumers, which are turned off in their entirety, if it comes to a short circuit or other process that requires ignition of the propellant charge of the pyrotechnic security element comes.

The conductor element may be formed as a part, but it may also consist of several parts.

Preferably, in a path between the pole of the vehicle battery and at least one second consumer, a safety device, which contains a fuse, but no pyrotechnic element, is provided. Thus, consumers can be switched as the second consumer, which should not be disconnected from their power supply in the event of an accident. These are, for example, the lighting devices of the vehicle and the automatic door closing, which should continue to be energized after the accident, so that the vehicle is still recognizable from the outside and the vehicle occupants can get off.

It is attempted that as many consumers as possible are among the first consumers. Thus, the power supply for as many consumers is interrupted by the pyrotechnic fuse element. In the event of an accident there is an increased risk that cables will be damaged and thus cause short circuits. Cables leading to first consumers, however, can no longer cause short circuits after the pyrotechnic element has been triggered. Only those cables which lead to the voltage supply connections of the second consumers are endangered. However, these must continue to be supplied with electrical energy so that the vehicle occupants can get off and thus the vehicle is still illuminated.

A method is also provided for triggering an illustrated security device. In this case, the vehicle has a sensor for detecting an accident. The sensor outputs a signal after detecting an accident, which causes the propellant charge of the pyrotechnic fuse element to explode.

Thus, a circuit breaker in the form of the pyrotechnic fuse element is combined with a fuse. With the fuse, the disconnection is started as soon as a short-circuit has occurred, whereby it is prevented that the predetermined current limits are exceeded. External activation is not necessary for this.

The pyrotechnic disconnector is started when activated externally. For example, if an airbag control module detects an accident, a signal is sent to the pyrotechnic fuse element to immediately interrupt the conductor element. The principle of the circuit breaker is based on a piece of metal which is cut, for example by a non-conductive piston, wherein the piston is driven by the pyrotechnic element.

The subject of the application will now be explained with reference to an embodiment. Showing:

1 a first embodiment of a safety device with a fuse and a predetermined breaking point, which are connected in series;

2 the safety device off 1 with triggered fuse;

3 the security device 1 out 1 after triggering a pyrotechnic fuse element;

4 a second embodiment of a securing device;

5 the safety device off 4 with triggered fuse;

6 the safety device off 4 when triggered pyrotechnic fuse element;

7 the housing of a security device;

8th a vehicle with a safety device integrated into the power supply.

1 shows a first embodiment of a safety device with a series circuit of a fuse and a predetermined breaking point for insertion into a circuit of a motor vehicle. The safety device 1 contains a housing 4 and a conductor element 2 partially in the housing 4 runs and in each case right and left protrudes from the housing. On the left side is a connection area 8th and on the right side a connection area 9 intended for connection of external cables. The conductor element 2 tapers inside the case 4 , Another rejuvenation of the conductor element 2 is in the range of a fuse 23 intended. In addition, a predetermined breaking point 22 in the conductor element 2 intended.

The case is made with an elastomer 5 filled. In this elastomer 5 there is a cavity 10 , which is a pyrotechnic fuse element 3 as well as a sealing plate 70 having. Within the elastomer is also a control device 11 provided, which has an input E and an output A. The input E has an external connection 6 that is on the outside of the case 4 is located, electrically connected. This external connection 6 is for connection to a signal cable 7 set up. With its output A is the control device with an input of the pyrotechnic security element 3 connected. The pyrotechnic fuse element has a propellant charge 32 and a trigger circuit 33 on.

The safety device 1 serves for connection in a current path of a voltage supply of a motor vehicle. This is done at one of the connection areas 8th and 9 a cable that leads to the negative pole of a vehicle battery, connected, while connected to the other of the connection areas 8th and 9 a cable is connected, which leads to voltage supply terminals of a plurality of first consumers. This leads to a flow of current through the conductor element 2 from the vehicle battery to the first consumers. If, for example, the cable leading to the first consumers is defective, because the insulation is faulty and causes a short circuit to the positive pole of the battery at the defective location, then the current I increases through the conductor element 2 ,

The fuse 23 is designed so that when exceeding a predetermined threshold, for example 60 A, the fuse 23 melts, causing the conductor element 2 is broken. It should be noted that the conductor element 2 can consist of one part. Often, however, is for the fuse 23 a different material than for the conductor element 2 used, so that the conductor element 2 consists of several parts. At an increased current becomes the conductor element 2 immediately interrupted, since it requires no evaluation circuit.

If, on the other hand, an accident is detected, this is detected by an airbag sensor which sends a corresponding signal to the signal line 7 impresses. The signal is sent via the signal line 7 and the outside connection 6 from the controller 11 at the input E of the control device 11 receive. The control device 11 outputs at its output A a signal which is used to ignite the trigger circuit 33 leads that the propellant charge 32 brings to exploding. This will make the sealing plate 70 pressed down, causing the breaking point 22 breaks. The current I can thus no longer through the conductor element 2 flow.

The cavity 10 serves to break the fragments of the predetermined breaking point 22 as well as the sealing plate 70 take. The elastomer 5 is compressible, so it's at the explosion of propellant charge 32 is compressed. This prevents the case 4 the security device 1 Total is damaged and that the propellant charge 32 outside the case 4 Causes damage.

2 shows the safety device 1 at a time following a severing of the conductor element 2 through the fuse 23 lies. The fuse 23 heats up when the current passes through the fuse 23 Exceeds 60 amps. This heating leads to melting of the lines in the fuse. The lines deform and cause an interruption of the current I through the conductor element.

3 shows the safety device 1 out 1 after triggering the pyrotechnic fuse element. It can be seen that the conductor element 2 at the position of the former breaking point is broken. In the lower area 120 of the cavity 10 there are fragments 100 of the conductor element 2 , the sealing plate and the pyrotechnic fuse element.

4 shows a second embodiment of the securing device 1 , Here are the predetermined breaking points 22 and the fuse 23 integrated in one place. This means that the area of the conductor element 2 who the fuse 23 forms, also a predetermined breaking point 22 is, in the case of triggering of the pyrotechnic securing element of the sealing plate 70 is severed.

In a vehicle where there are multiple airbags and airbag control modules, each of the modules outputs a signal indicating whether it has detected an accident. The various signals may be received by the controller. In this embodiment according to 4 The output signals from two airbag control modules are via signal lines 71 and 72 output. The safety device 1 of the 4 has two external connections 61 and 62 on, the control device 11 at a first input E1 with the external connection 61 and with a second input E2 to the external connection 62 connected is. The signal line 71 is with the outside connection 61 and the signal line 72 is with the outside connection 62 connected.

In the control device 11 the signals are received at the inputs E1 and E2 and it is decided according to the input signals, whether the pyrotechnic fuse should trigger. For example, the pyrotechnic fuse only if both airbag control modules have detected an accident trigger. It is understood that by modification of the securing device 1 Also, a variety of other signals from various sensors in the decision-making can be considered.

5 shows the safety device 1 out 4 after the fuse 23 was triggered. The current I through the conductor element 2 was greater than 60 A, leaving the conductor element 2 in the area of the fuse 23 is melted, causing the conductor element 2 was interrupted.

6 shows the safety device 1 to 4 after triggering the pyrotechnic fuse element. The conductor element 2 is in the lower range 120 the breaking point 22 breached. In the area below 120 of the cavity 10 lie fragments 100 the sealing plate, the conductor element 2 and the pyrotechnic fuse element.

7 shows a safety device 1 in a plan view obliquely from above. The safety device 1 can according to the first embodiment according to 1 or according to the second embodiment according to 4 be educated. On the left, the connection area protrude 8th and on the right the connection area 9 out. At the front of the case 4 is the external connection 6 recognizable. This can be designed as an external electrical contact to which a cable can be soldered, but also as a plug. The connection areas 8th and 9 each have openings 30 on, each serving to receive a screw connection.

8th shows a motor vehicle 40 with a safety device 1 in the path between the negative terminal of a vehicle battery and a plurality of power supply terminals of first consumers 42 is provided. A second security device 50 , which contains only a fuse, is between the negative pole of a vehicle battery 41 and a supply terminal of a second consumer 43 intended. The second supply connections of the first consumers 42 and the second consumer 43 are each with the positive pole of the vehicle battery 41 connected. At the second consumers 43 These are safety-critical consumers who also need to be supplied with electrical energy in the event of an accident. These are, for example, door closing automatic and lighting devices of the motor vehicle. The first consumers are consumers who are shut down in the event of an accident so that no live conductors cause further damage. These are consumers such as engine control, driver assistance systems and infotainment devices. In 8th are also a first airbag control module 200 and a second airbag control module 201 shown with signal outputs to the signal lines 71 respectively 72 are connected.

Particularly suitable is the safety device for vehicles, in which the main supply line is guided below the vehicle from the battery to the consumers. The main supply line should be disconnected in case of mechanical damage. At the same time, care should be taken to ensure that enough electrical energy is available to unlock the doors in the event of an accident. In addition, alarm signals should be transmitted electrically and the lighting in the vehicle and outside the vehicle should continue to be powered.

Although at least one exemplary embodiment has been shown in the foregoing description, various changes and modifications may be made. The above embodiments are merely examples and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing description provides those skilled in the art with a plan for practicing at least one example embodiment, and wherein numerous changes can be made in the operation and arrangement of elements described in an exemplary embodiment without departing from the scope of the appended claims and their legal equivalents ,

LIST OF REFERENCE NUMBERS

1

safety device

2

conductor element

3

Pyrotechnic fuse element

4

casing

5

elastomer

6

external connection

7

signal line

8th

terminal area

9

terminal area

10

cavity

11

control device

22

Breaking point

23

fuse

30

opening

32

propellant

33

tripping circuit

40

motor vehicle

41

vehicle battery

42

first consumer

43

second consumer

50

safety device

61

external connection

62

external connection

70

sealing plate

71

signal line

72

signal line

100

fragments

120

lower area

200

first airbag control module

201

second airbag control module

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 69414798 T2 [0002]
• DE 10049071 A1 [0003]

Claims (11)

Safety device ( 1 ) for a power supply of a motor vehicle, comprising: - a conductor element ( 2 ), which is a predetermined breaking point ( 22 ), - a pyrotechnic fuse element ( 3 ) with a propellant charge ( 32 ), which upon triggering the predetermined breaking point ( 22 ) of the conductor element, - a fuse ( 23 ) in the conductor element ( 2 ), which cuts through the conductor element when a predetermined current is exceeded by melting. Securing device according to claim 1, wherein the predetermined breaking point ( 22 ) and the fuse ( 23 ) are connected in series. Securing device according to claim 1, wherein the fuse ( 23 ) also the predetermined breaking point ( 22 ). Securing device according to one of claims 1 to 3, wherein the securing device ( 1 ) a housing ( 4 ), wherein on the housing ( 4 ) electrical external terminals are attached, with which the explosive charge of the pyrotechnic fuse element ( 3 ) from outside the housing ( 4 ) can be triggered. Securing device according to one of claims 1 to 4, wherein the pyrotechnic securing element ( 3 ) and the fuse ( 23 ) in a housing ( 4 ) are integrated. Securing device according to one of claims 1 to 5, wherein a control device ( 11 ) is provided for triggering the propellant charge ( 32 ) of the pyrotechnic fuse element ( 3 ), wherein the control device ( 11 ) is arranged to receive and evaluate a plurality of input signals. Safety device according to claim 6, wherein the control device ( 11 ) in the same housing ( 4 ) like the pyrotechnic fuse element ( 3 ) is provided. Securing device according to one of claims 1 to 6, wherein the conductor element ( 2 ) contains a stamped part made of copper. Vehicle with a safety device according to one of claims 1 to 8, wherein the safety device ( 1 ) in the path between a pole (-) of a vehicle battery ( 41 ) on the one hand, and a large number of first consumers ( 42 ) is switched on the other hand. Vehicle according to claim 9, wherein in the path between the pole of the vehicle battery ( 41 ) and at least one second consumer ( 43 ) a second security device ( 50 ), which is a fuse ( 23 ) but does not contain a pyrotechnic element is provided. Method for triggering a safety device according to one of claims 1 to 9 in a vehicle, wherein the vehicle has a sensor for detecting an accident, wherein the sensor outputs a signal after detecting an accident that the propellant charge ( 32 ) of the pyrotechnic fuse element ( 3 ) brings to explode.

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