EP3618089B1 - Pyrotechnic current disconnector - Google Patents

Description

Technical area

The present invention relates to a pyrotechnic current isolator which has a housing with an igniter which, in order to separate a conductor, applies pressure to a separating piston which is displaceable in the housing, a signal line also being interrupted when triggered.

State of the art

The increase in traffic and the associated pollutant emissions from vehicles are now a major problem, especially in inner-city areas. Electric (BEV) and hybrid vehicles are currently seen as a possible solution, with the latter being predicted to increase. The advantage of hybrid vehicles is that a motor / generator element is used for the frequent starting and braking processes, which has a high degree of efficiency when starting and which feeds the energy back into the power storage unit when braking. This energy storage device, which is small compared to a fully electric vehicle, still has a very high short-circuit current, which must be reliably switched off in the event of damage.

Power isolators for automotive applications have been known for a long time, typical versions are the PSS1 and PSS2 from Autoliv, whose basic structure is shown in the DE 102004023415 A is described. Due to the construction by means of multiply angled conductors, these can only be produced with considerable financial outlay and have only limited protection against water.

Another design is in the WO 2012/025272 A the company Autokabel described, here the manufacture of the conductor by soldering the two conductor sections is a main cost driver. Here the separation is not carried out by a separating piston, but by a liquid / pasty separating and extinguishing agent. The mandatory filling with liquid / pasty separating and extinguishing agent is only necessary for certain requirements.

The issue of proof of tripping by opening a signal line has not been adequately resolved. Autokabel uses a magnet in the separating piston, which triggers an external magnetic switch. A signal cable is provided in the Autoliv PSS3, which should be cut in addition to the conductor during the cutting process. A top plate is provided here, which provides a guide for the signal line. The cutting of the signal cable serves to prove that the conductor has been cut. The piston has a protruding nose for the signal cable, under which the signal cable is arranged. The signal cable is fixed in the top plate on both sides of the nose.

The disadvantage of both solutions is the additional manufacturing effort, be it the additionally attached magnetic switch, be it the top plate, which must also be manufactured and attached from the document DE 10 2010 045 726 A1 a pyrotechnic current isolator is known which has the features of the preamble of claim 1.

Brief description of the invention

The object of the present invention is to simplify the construction of the current isolator and thereby reduce the manufacturing costs.

This object is achieved according to the invention by a current isolator of the type mentioned at the outset in that the signal line is designed as a loop into which a pin of the isolating piston engages.

A loop can be attached to the housing with significantly less manufacturing effort. However, with a normal piston - even if it has a nose - there is a risk that the loop will be pressed into the small gap between the piston and the housing and will not be severed. However, this is reliably prevented as a result of the pin of the separating piston, which engages in the loop.

The separating device is preferably designed in such a way that the signal line is only cut through after the conductor has been separated. In this way, it is impossible for "conductor disconnected" to be incorrectly signaled.

After severing the conductor and severing the signal line, the piston preferably serves as insulation for both the interrupted conductor and the interrupted signal cable. In this way it is impossible for the signal line to bridge the separation point of the conductor.

If the signal line has sufficient mechanical stability, that is to say is sufficiently thick, it is often sufficient if the separating piston is only fixed in position by the pin engaging the loop. Otherwise, for fixing the position, it is preferred that the separating piston is positioned opposite the conductor by at least one web.

An advantageous embodiment of the invention consists in that the housing is composed of an upper part and a lower part, with the igniter and the upper part also being overmolded, as shown in FIG WO 2017/066816 A is known.

The electrical contacting of the circuit breaker's ignition circuit can be made, for example, as a pin-type or leadwire variant.

Particularly with Leadwire variants, i.e. where the contact points of the igniter and conductor are led out to an external plug, it is advantageous if the igniter's lead is also encapsulated. In this case in particular, the signal line can be designed in one piece.

The signal line can be encapsulated with the lower part. In this way, assembly is possible without any problems because when the lower part is placed on the upper part in which the piston is located, the loop wraps around the pin of the piston. However, a common connector for the igniter, which is in the upper part, and the signal line, which is in the lower part, is not possible.

According to a further embodiment of the invention, it is therefore provided that the signal line is encapsulated with the upper part, the loop exiting at the separating surface to the lower part and being guided between the upper part and the lower part to the separating piston. In this case, the assembly can be done in such a way that the signal line emerges from the upper part first parallel to the direction of movement of the piston, then the piston is inserted, whereupon the loop is bent by 90 ° onto the trend area between the upper part and the lower part and thereby around the pin of the Piston comes to rest. Then the lower part can be attached.

A favorable further training is that with this Embodiment, the signal line and the igniter have a common plug for connection. This ensures a more economical manufacturing process and is made possible, among other things, by the fact that no additional top plate is required, as is the case with the PSS3 from Autoliv. It is particularly favorable when the plug is part of the housing.

In the Leadwire version, it is preferred if both the signal line and the ignition line exit the housing parallel to the conductor plane. This is favorable for a space-saving installation and can be used both when the signal line is encapsulated in the upper part and when it is encapsulated in the lower part.

The signal line can have many cross-sectional shapes, but a rectangular cross-section is preferably used. As a result, the signal line comes to rest flat around the pin.

Brief description of the drawing figures

The present invention is explained in more detail with the aid of the accompanying drawings. It shows: Fig. 1 a current isolator according to the invention in section, Fig. 2 a variant of this with a different braking of the separating piston, Fig. 3 a circuit breaker with an integrated signal line, which is also disconnected when the pyrotechnic switch is triggered, in a section that compares to Figs. 1 and 2 is guided rotated by 90 °, and Fig. 4 the isolating piston of the isolator from Fig. 3 in perspective view.

Description of the types of execution

According to Fig. 1 a circuit breaker 1 according to the invention has a conductor 2 with conductor sections 3a, 3b, the conductor 2 being able to be fixed in the housing through holes 4a, 4b. The housing consists of an upper part 5 and a lower part 6. In the upper part there is an igniter 7 and a separating piston 8 with a groove 9 which contains an O-ring 10. The conductor 2 has two predetermined breaking points 11a, 11b in the interior of the housing, which delimit a central section 12. If this section 12 is separated from the conductor 2, it is also called a circuit board. As far as the design corresponds to the existing concepts.

In order to prevent the cut-off circuit board from coming into contact again, it is necessary for the circuit board to be held in place by structural elements in the lower part 6 after the circuit breaker 1 has been triggered. These structural elements can, for example, have a knob-like design.

The separating piston 8 preferably has a concave cutting surface which enables the conductor 2 to be separated cleanly.

Furthermore, a clean separation process is made possible by the fact that the conductor 2 has a greater width outside the housing than at the separation points.

In contrast to this, the upper part 5 and the lower part 6 are held together by screws 13a, 13b, which lead through the conductor 2 and thus not only fix the conductor 2 and hold the housing halves together, but also reinforce them. This means that additional metallic reinforcements are not required. In the holes 4a, 4b through the conductor sections 3a, 3b, insulation 14a, 14b can prevent contact between the screws 13a, 13b and the conductor sections 3a, 3b. This insulation can be part of the upper or lower part 5 or 6 or a separate part.

The screws 13a, 13b are particularly preferably inserted from the side remote from the igniter, as a result of which the heads 15a, 15b of the screws 13a, 13b become a structural reinforcement of the lower part 6. As a result, the blank 12 punched out by the separating piston 8 during the separating process can be safely caught.

The collecting chamber 16 for the plate 12 is conical, so that when the plate 12 (and possibly the separating piston 8) is braked, a bending moment is generated on the screws 13a, 13b and these serve as structural reinforcement. This bending moment presses the screws against the plastic in the transverse direction, which increases their axial holding force. In this design, the screws 13a, 13b can also be inserted from the igniter side.

As screws, screws with plastic threads are preferred. Compared to metric screws, these have a large pitch, significantly more material between the threads and a characterized largely axial load on the carrier material. Particularly preferred are screws with pull-out forces of at least 500 N. The screws can be equipped with a safeguard against automatic loosening (for example in the event of vibration), for example by means of serrations or ribs on the screw head.

The screws can have a contour on the head for transmitting the screwing and tightening torque, which becomes ineffective when a defined torque is reached, for example if part of the head is torn off. This effectively prevents disassembly.

To achieve watertightness, especially after the shot, a seal 17 is provided; this is particularly preferably sprayed onto the conductor 2 and consists of conventional sealing materials, for example EPDM or TPE with approx. 70 Shore; here, too, the fixation of the conductor sections 3a helps , 3b during and after the separation process by the screws 13a, 13b to ensure the tightness.

In Fig. 2 Another design is shown in which the separating piston 8 is designed as a stepped piston and the position of the predetermined breaking points 11a, 11b and the diameter of the collecting chamber 16 are adapted to the smaller diameter 19 remote from the fuse. In this design, the smaller diameter 19 remote from the fuse separates the central section 12 of the conductor 2 when the igniter 7 is activated from the conductor 2, the conductor sections 3a, 3b subsequently serving as a path limitation for the separating piston 8 and therefore the fixing of the conductor ends by the screws is particularly cheap. If the step of the piston is inclined (frustoconical), forces act on the conductor sections 3a, 3b in their longitudinal direction, whereby the screws are in turn pressed laterally against the plastic.

A current isolator 1 of the type described above can also be equipped with an additional isolating device for a signal line 18, as shown in FIG Fig. 3 is shown. This additional separating device generally only becomes effective after the conductor 2 has been separated, in order to document the separating process and to initiate any subsequent steps. A separating piston 8 according to the invention in combination with the signal line 18 is shown in FIG Fig. 4 shown.

The separating piston 8 has a predetermined orientation to the conductor 2, which is ensured in the exemplary embodiment by tabs 16a, 16b. The signal line 18 has two ends 19a, 19b and a separating area 20. A pin 21 of the separating piston 8 engages in the separating area 20 of the signal line 18. When the igniter 7 is ignited, the separating piston 8 separates the central section 12 of the conductor 2, and the pin 21 of the separating piston 8 tears the signal line 18 through. In the preferred embodiment, the geometry of the separating area of the signal line 18 and the pin 21 is designed in such a way that the conductor 2 is separated first and only then is the signal line 18 separated. An embossing of the signal line 18 ensures a more precise definition of the tear-off point.

The separating piston 8 ensures the insulation between conductor 2 and signal line 18 before, during and after the separating process.

The assembly is particularly advantageous in that the conductor loop of the signal line 18 protrudes downwards from the upper part 5 after the encapsulation, the separating piston 8 with O-ring 10 is inserted and the conductor loop of the signal line 18 on the interface between the upper part 5 and the lower part 6 and over the pin 21 of the separating piston 8 is bent, after which the lower part 6 is placed and screwed on.

In a so-called leadwire design, i.e. the contact points of igniter 7 and signal line 18 are led out to an external plug, the signal line can be made in one piece. In this case, the signal line is a wire or a stranded wire, which preferably has no insulation in the separation area and is injected into the housing.

Furthermore, in the case of Leadwire variants, where the igniter 7 and the ignition line are also injected into the upper part, it is particularly advantageous if the signal line 18 is also injected into the housing, specifically in the lower part 6.

In a preferred variant, the cables of the ignition line leave the upper part 5 parallel to the conductor plane, and the cables of the signal line 18 leave the lower part 6 also parallel to the conductor level, particularly preferably the ignition line and the signal line exit in the same direction. If necessary, a plug connection can also be attached here.

The watertightness of this system can be achieved by a sealing ring - as shown above - mostly in combination with a (four-pole) watertight plug or two (two-pole) watertight plugs.

Claims (13)

1. A pyrotechnic current disconnector (1) including a housing having an igniter (7) which, for disconnecting a conductor (2), applies pressure to a disconnecting piston (8) displaceable in the housing, wherein upon triggering a signal line (18) is interrupted, too, wherein the signal line (18) is formed as a loop, characterised in that a pin (21) of the disconnecting piston (8) engages the loop.
2. The pyrotechnic current disconnector (1) according to claim 1, characterised in that the signal line (18) is only cut after disconnecting the conductor (2).
3. The pyrotechnic current disconnector according to claim 1 or 2, characterised in that, after triggering the circuit disconnector (1), upon interrupting the signal line (18) a separation point is created on the signal line (18), and that this separation point of the signal line (18) is insulated from the conductor (2) by the disconnecting piston (8).
4. The pyrotechnic current disconnector (1) according to any one of the claims 1 to 3, characterised in that the disconnecting piston (8) is positioned against the conductor (2) by at least one bar.
5. The pyrotechnic current disconnector (1) according to any one of the claims 1 to 4, characterised in that the housing is composed of an upper part (5) and a lower part (6), wherein the igniter (7) is overmoulded with the upper part (5).
6. The pyrotechnic current disconnector (1) according to claim 5, characterised in that the igniter (7) includes supply lines, and these supply lines are overmoulded with the upper part (5) of the housing.
7. The pyrotechnic current disconnector (1) according to claim 5 or 6, characterised in that the signal line (18) is overmoulded with the lower part (6).
8. The pyrotechnic current disconnector (1) according to claim 5 or 6, characterised in that the upper part (5) and the lower part (6) are assembled at a separating surface, and the signal line (18) is overmoulded with the upper part (5), wherein the loop is exiting at the separating surface to the lower part (6), and is guided between the upper part (5) and the lower part (6) to the separating piston (8).
9. The pyrotechnic current disconnector (1) according to claims 5 and 8, characterised in that the signal line (18) and the igniter (7) have a common plug for connection.
10. The pyrotechnic current disconnector (1) according to claim 9, characterised in that the plug is part of the housing.
11. The pyrotechnic current disconnector (1) according to claim 6 and 7 or 8, characterised in that the conductor (2) includes a conductor plane, and the signal line (18) and the ignition line exit in parallel to the conductor plane from the housing.
12. The pyrotechnic current disconnector (1) according to any one of claims 1 to 11, characterised in that the signal line (18) is formed integrally.
13. The pyrotechnic current separator (1) according to any one of the claims 1 to 12, characterised in that the signal line (18) has a rectangular cross-section.

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