EP3618090A2 - Pyrotechnic current disconnector - Google Patents

Abstract

A pyrotechnic current isolator (1) for severing a conductor (2) by means of a separating piston (8) is composed of a lower part (6) and an upper part (5) in which an igniter (7) is arranged. The conductor (2) is inserted between the lower part (6) and the upper part (5) and has holes (4a, 4b). According to the invention, the screws (13a, 13b), which connect the lower part (6) and the upper part (5) to each other, extend through the holes (4a, 4b), so that no additional elements are required to fix the conductor (2) in the longitudinal direction . The screws (13a, 13b) also serve to stiffen the housing. If e.g. A collecting chamber for the separating piston (8) or the circuit board (12) punched out by it tapers away from the conductor (2) ) is recorded.

Description

Technical field

The present invention relates to a pyrotechnic current isolator in which a conductor is severed by pressurization, the current isolator having a housing which has a lower part and an upper part with an igniter, the lower part and the upper part being connected to one another by screws and the conductor between the lower part and Upper part is inserted and has holes through which elements extend which fix the conductor in the longitudinal direction.

State of the art

The increase in traffic and the associated pollutant emissions from vehicles have become a major problem, especially in inner-city areas. Electric and hybrid vehicles (BEV) and hybrid vehicles are currently seen as a possible solution, with the greatest growth predicted for the latter. 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 returns the energy to the energy storage when braking. This electricity storage, which is small compared to a fully electric vehicle, nevertheless has a very high short-circuit current, which must be reliably switched off in the event of damage.

Current isolators for automotive applications have been known for a long time, typical versions are the PSS1 and PSS2 from Autoliv, whose basic structure is in the DE 102004023415 A is described. However, due to the construction by means of a multi-angled conductor, these can only be produced at considerable financial expense and have only limited protection against water.

Another design is in the WO 2012/025272 A from the company Autokabel, 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 release and extinguishing agent is only required for certain requirements.

Finally, there are the concepts of Safran, WO 2016/038044 A , the principle of which is also an elaborate multi-stage separation of the conductor, here too the manufacture of the conductor is complex and the system is not watertight. Here the housing consists of an upper part and a lower part, the upper part and lower part are held together by four screws at the four corners.

A device of the type mentioned is out WO 2017/066816 A known. Here, too, the housing is held together by screws, nuts being provided as a counterpart to the screws. The conductor is fixed in the housing using pins.

Brief description of the invention

It is an object of the present invention to simplify the construction of this current isolator and thereby to 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 elements which fix the conductor in the longitudinal direction are formed by the screws which connect the lower part and the upper part to one another.

According to the invention, the screws fulfill a double function: they not only hold the upper part and lower part together, but also fix the conductors in the housing. This not only saves components, it also simplifies assembly.

The screws are preferably insulated from the conductor. This prevents the separation point from being bridged by connecting the screws after the conductor has been separated. This insulation can be done by a sleeve, which can also be molded onto the upper part or lower part.

In a preferred embodiment, the current isolator has a separating piston which, when the conductor is separated, punches a circuit board out of the conductor, so that two conductor sections separated from one another remain, a collecting chamber for the circuit board and the separating piston being provided on the side of the conductor remote from the igniter, as is also the case with the generic one WO 2017/066816 A the case is.

If the collecting chamber tapers away from the conductor so that a bending moment arises when the circuit board and separating piston are braked, this is absorbed by the screws. So the screws stiffen the housing.

As an alternative to this, the separating piston can be braked in that it is designed in steps so that the separating piston hits the conductor sections with the step. Since the conductor sections are fixed by the screws, the force required for braking is also transmitted to the screws and absorbed by them.

If the step is carried out obliquely, there is also a force on the conductor sections in their longitudinal direction, which is directly absorbed by the screws as a transverse force, so that the stress on the screws is reduced in tension.

In the case of the graduated separating piston in particular, it is advantageous if the heads of the screws rest on the lower part and thereby reinforce the housing in the area of impact of the separating piston and circuit board.

The conductor is preferably sealed off from the housing by a seal against the ingress of water. If the seal is sprayed onto the conductor, no additional components are necessary.

The screws are preferably secured against automatic loosening. This can be done in a known manner using an adhesive.

Furthermore, the screws can be secured against deliberate loosening. This can be done by means of a screw contour that is destroyed when a dedicated tightening torque is reached, e.g. by means of a multi-part screw head, at least part of which breaks off when a dedicated tightening torque is reached. But it can also be done using a screw contour that only allows the force to be applied in one direction, e.g. the directional application of force can take place over at least one surface with a wedge-shaped cross section.

The screws are preferably directly in the plastic existing bottom part or top part screwed in and have a thread optimized for adhesion in plastic. In this way you can not only save the nuts and thus simplify assembly, the housing is also better stabilized due to the direct connection of the screw and the upper or lower part. The screws preferably have an extraction force of at least 500 N.

Brief description of the drawing figures

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

Description of the execution types

According to Fig. 1 A current isolator 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 5 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. So far the design corresponds to the existing concepts.

In order to prevent the separated circuit board from coming into contact again, it is necessary for the circuit board to be held in the lower part 6 by structural elements after the current isolator 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 a clean separation of the conductor 2.

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

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 can be omitted. 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 an independent 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 circuit board 12 punched out by the separating piston 8 during the separating process can be securely caught.

The collecting chamber 16 for the circuit board 12 is conical, so that when the circuit board 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 causes the screws to be pressed 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.

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

The screws can have a contour on the head for transmitting the screwing-in and tightening torque, which becomes ineffective when a defined torque is reached, for example by tearing off part of the Head. 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 approximately 70 Shore, the fixing of the conductor sections 3a also helps here , 3b during and after the separation process by the screws 13a, 13b to ensure tightness.

In Fig. 2 A further 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 igniter. In this design, the smaller diameter 19 remote from the igniter separates the central section 12 of the conductor 2 from the conductor 2 when the igniter 7 is activated, the conductor sections 3a, 3b subsequently serving to limit the distance 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 oblique (frustoconical), forces act on the conductor sections 3a, 3b in their longitudinal direction, as a result of which the screws are again 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 becomes effective only after the conductor 2 has been separated in order to document the separation 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. 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 through the signal line 18. In the preferred embodiment, the geometry of the separation area of the signal line 18 and the pin 21 is designed such that the conductor 2 is disconnected first and then the signal line 18 is separated. An embossed signal line 18 provides a more precise definition of the tear point.

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

The assembly is particularly advantageous in that the conductor loop of the signal line 18 protrudes downward from the upper part 5 after the encapsulation, the separating piston 8 with the 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 version, i.e. leading out the contact points of igniter 7 and signal line 18 to an external connector, the signal line can be made in one piece. In this case, the signal line is a wire or a strand, which preferably has no insulation in the separation area and is also injected into the housing.

Furthermore, in the case of lead wire variants, where the igniter 7 and the ignition line are also injected in the upper part, it is particularly advantageous if the signal line 18 is also injected in 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 level, and the cables of the signal line 18 also leave the lower part 6 parallel to the conductor level, particularly preferably the ignition line and the signal line exit in the same direction. If required, a connector 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-pin) waterproof connector or two (two-pin) waterproof connectors.

Claims (11)

Pyrotechnic current isolator (1), in which a conductor (2) is severed by pressurization, the current isolator (1) having a housing which has a lower part (6) and an upper part (5) with an igniter (7), the lower part (6) and upper part (5) are connected to one another by screws (13a, 13b) and the conductor (2) is inserted between lower part (6) and upper part (5) and has holes (4a, 4b) through which elements extend which fix the conductor (2) in the longitudinal direction, characterized in that the elements which fix the conductor (2) in the longitudinal direction connect to one another by means of the screws (13a, 13b), the lower part (6) and the upper part (5), are formed. Pyrotechnic current isolator according to claim 1, characterized in that the screws (13a, 13b) are insulated from the conductor (2). Pyrotechnic current isolator according to Claim 1 or 2, characterized in that the current isolator (1) has a separating piston (8) which, when the conductor (2) is separated, stamps a circuit board (12) out of the conductor (2), so that two are separated from one another Conductor sections (3a, 3b) remain and that a collecting chamber (16) for the circuit board (12) and the separating piston (8) is provided on the side of the conductor (2) remote from the igniter. Pyrotechnic current isolator according to claim 3, characterized in that the collecting chamber tapers away from the conductor (2), so that when the circuit board (12) and separating piston (8) are braked, a bending moment arises which is absorbed by the screws (13a, 13b). Pyrotechnic current isolator according to claim 3, characterized in that the separating piston (8) is of stepped design so that the separating piston (8) strikes the conductor sections (3a, 3b) with the step and is thereby braked. Pyrotechnic current isolator according to claim 5, characterized in that the step is inclined. Pyrotechnic current isolator according to one of claims 1 to 6, characterized in that the heads (15a, 15b) of the screws (13a, 13b) rest on the lower part (6) and thereby the housing in the area of impact from Reinforce the separating piston (8) and circuit board (12). Pyrotechnic current isolator according to one of claims 1 to 7, characterized in that the conductor (2) is sealed against the housing by a seal (17) against the entry of water. Pyrotechnic current isolator according to claim 8, characterized in that the seal (17) is sprayed onto the conductor (2). Pyrotechnic current isolator according to one of Claims 1 to 9, characterized in that the screws (13a, 13b) have a safety device against automatic loosening and / or against deliberate loosening. Pyrotechnic current isolator according to one of Claims 1 to 10, characterized in that the screws (13a, 13b) are screwed directly into the lower part (6) or upper part (5) made of plastic and have a thread which is optimized for adhesion in plastic.

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