DE102013013177B4 - Airbag unit with a control device - Google Patents

Abstract

Airbag unit with an airbag (10) enclosing at least one chamber, a carrier component, in particular a housing (20), for receiving the gasbag (10), an inflator held on the carrier component for filling the at least one chamber and a control device for actively influencing the geometric shape of the Gas-filled gas bags (10) and / or the ventilation of the at least one chamber, the control device having at least one pulling element (80) extending from a first end to a second end, the first end of which is connected to the gas bag (10) or a ventilation device and the second end of which, in an initial state, is at least indirectly connected to the carrier component, and a separating device which, in response to an external signal, separates the second end of the tension element (80) from the carrier component or cuts the tension element (80), the separation device comprising a pyrotechnic charge (74 ), which is based on the external signal acts directly thermally on the tension element (80) so that it melts in sections or loses its strength, the pyrotechnic charge (74) being in flow communication with a cavity through which a section of the tension element (80) runs, characterized in that that the section of the tension element (80) on which the pyrotechnic charge (74) acts consists of a plurality of filaments (84) extending parallel to one another and extending between two end pieces (86a, 86b).

Description

The invention relates to an airbag unit with a control device according to the preamble of claim 1.

Gas bag units, which have a control device for influencing the geometric shape and / or the ventilation state of the gas bag, are known in large numbers. Such control devices often have a drawstring or another pull element, the first end of which is connected to the gas bag or a ventilation device and the second end of which is connected to a component which is fixed to the vehicle, such as the housing of the gas bag module. The length of the drawstring is chosen so that when the gas bag is fully expanded, it comes under tension, so that the shape of the gas bag is influenced or a ventilation device brings or holds it in a predetermined state (usually the closed state). Furthermore, there is a separating device which, in response to an external (mostly electrical) signal, cuts through the tension element or separates the second end of the tension element from the component which is fixed to the vehicle.

Two embodiments of such a separation device are in the US 2009/0302588 A1 described. Both embodiments of this separating device work with mechanically moving parts, which are driven by memory elements designed as springs. However, it is also known to drive corresponding mechanically movable parts by means of a pyrotechnic charge. The first embodiment of the US 2009/0302588 A1 works like a guillotine and cuts the tension element when actuated. In the second embodiment, the second end of the tension element is held on a bolt which, when actuated, is brought into a different position so that the second end of the tension element, which is designed as a loop, comes out of engagement with the bolt. In this case there is a combined holding and separating device since the bolt initially serves as a holding part.

Such mechanically operating separating devices work very well in principle, but have the disadvantage that, owing to the need for mechanically movable parts, the production outlay and the quality assurance outlay are relatively high, since it must of course be ensured that the mechanically movable parts do not jam when actuated or the like. Furthermore, the functional reliability must of course be ensured over the entire expected service life of the motor vehicle.

In the generic DE 696 19 103 T2 describes a gas bag unit with a thermal separation device. The section of the tension element adjacent to the second end here runs through a cavity in which a pyrotechnic charge is also arranged. If this pyrotechnic charge is ignited, the section of the tension element melts, so that the tension element is severed.

Proceeding from this, the object of the invention is to further develop an airbag unit of the generic type in such a way that it has an improved reaction speed.

This object is achieved by an airbag unit with the features of claim 1.

As from the DE 696 19 103 T2 Known, the separating device does not act mechanically, but thermally on the tension element, so that when the separating device is actuated it melts, sublimates or at least loses its strength. For this purpose, the separating device has a heat generator in the form of a pyrotechnic charge.

There is therefore no need for mechanically moving parts, which, in addition to the above-mentioned simplification in terms of production and quality control, also means that the separating device can be designed with a very low mass.

According to the invention, the section of the tension element on which the pyrotechnic charge acts consists of a plurality of filaments extending parallel to one another and extending between two end pieces. This increases the melting or sublimation speed.

• 1 eine Gassackeinheit in einer schematisierten Schnittdarstellung in einem Ausgangszustand,
• 2 die Gassackeinheit aus 1 nach Zündung des Gasgenerators und darauffolgender Expansion des Gassackes,
• 3 das in 2 Gezeigte nach Betätigung einer Trennvorrichtung für ein Zugelement, was zur Öffnung einer Ventilationseinrichtung führte,
• 4 das Detail D aus den 1 und 2 im Zustand der 1 und 2, nämlich ein Halteteil mit integrierter Trennvorrichtung,
• 5 das in 4 Gezeigte im Augenblick der Betätigung der Trennvorrichtung,
• 6 das in 5 Gezeigte zu einem etwas späteren Zeitpunkt,
• 7 das in 6 Gezeigte zu einem noch etwas späteren Zeitpunkt,
• 8 eine alternative Ausführungsform des Halteteils mit integrierter Trennvorrichtung in einer Darstellung entsprechend der 4,
• 9 das in 8 Gezeigte in einer der 7 entsprechenden Darstellung,
• 10 ein weiteres Ausführungsbeispiel in einem der 4 entsprechenden Zustand und
• 11 die erfindungsgemäße Trennvorrichtung in einer der 4 entsprechenden Darstellung.

Preferred exemplary embodiments result from the further subclaims and from the exemplary embodiments now illustrated in more detail with reference to the figures. Here show:

• 1 a gas bag unit in a schematic sectional view in an initial state,
• 2 the gas bag unit 1 after ignition of the gas generator and subsequent expansion of the gas bag,
• 3 this in 2 Shown after actuation of a separating device for a tension element, which led to the opening of a ventilation device,
• 4 the detail D from the 1 and 2 in the state of 1 and 2 , namely a holding part with an integrated separating device,
• 5 this in 4 Shown at the moment the separator is actuated,
• 6 this in 5 Shown at a slightly later time
• 7 this in 6 Shown at a slightly later time
• 8th an alternative embodiment of the holding part with integrated separation device in a representation corresponding to the 4 .
• 9 this in 8th Shown in one of the 7 corresponding representation,
• 10 another embodiment in one of the 4 appropriate condition and
• 11 the separation device according to the invention in one of the 4 corresponding representation.

The 1 shows a complete airbag unit, namely a driver front airbag unit in a sectional view. As usual, this airbag unit has an airbag 10 , a housing 20 into which the gas bag 10 is folded, and a gas generator serving as an inflator 25 on. In the embodiment specifically shown is a deflector-diffuser component 30 provided which by means of a bottom portion 32 the gas bag 10 on the case back 22 of the housing 20 holds and which still has a diffuser section 39 which has the gas generator 25 spans.

The gas bag 10 , which surrounds a chamber, has a ventilation device for ventilation of this chamber. This is an adaptive ventilation device which, in the specific embodiment shown, consists of a ventilation opening 12 in the gas bag 10 and one the ventilation opening 12 encircling spout 14 consists of how this basically consists of the US 2006/0071461 A1 is known, so that there is no need to go into detail here. A control device for this adaptive ventilation device is provided, which consists of a tension element 80 and a holding part 60 with integrated separator.

The first end of the tension element is with the grommet 14 connected and the second end of the tension element 80 is in the initial state by means of the holding part 60 with integrated separator fixed to the housing or the deflector-diffuser component 30 connected. On the exact structure of the holding part 60 with integrated separating device and its connection to the deflector-diffuser component or to the housing 20 will later refer to the 4 to 9 discussed in more detail, the 4 the detail in the 1 and 2 shows.

The basic mode of operation of the gas bag unit is known: the gas generator 25 Operated via its ignition cable, the escaping gas fills the gas bag chamber 10 so the gas bag 10 out of the housing 20 exits and is in its fully expanded state as it is in 2 is shown. The tension element is in this state 80 under tension, so the spout 14 is contracted and little or no gas can flow out of the chamber through the ventilation opening. Will the tension element 80 severed in the region of its second end by the separating device or by the holding part 60 released, the tension element loses 80 its tension and the spout 14 is turned outwards by the gas pressure prevailing in the chamber, so that gas flows through the ventilation opening 12 can flow off like this in 3 is shown.

• Im konkret gezeigten Ausführungsbeispiel ist ein zweiteiliges Halteteil 60 mit integrierter Trennvorrichtung vorhanden. Eine entsprechende zweiteilige Ausbildung ist für den erfindungsgemäßen Erfolg nicht notwendig, ebenso ist es nicht zwingend notwendig, die Trennvorrichtung in das Halteteil 60 zu integrieren. Das konkret gezeigte Ausführungsbeispiel ist jedoch hinsichtlich seiner Montagefreundlichkeit sehr vorteilhaft: Das Halteteil 60 mit integrierter Trennvorrichtung (im Weiteren ist nur vom Halteteil 60 die Rede) weist einen Hohlkörper 62 und ein in den Hohlkörper 62 ragendes Bauteil 70, welches eine pyrotechnische Ladung 74 trägt, auf (in der gezeigten Geometrie ragt das Bauteil 70 von unten in den Hohlkörper 62). Der Hohlkörper 62 weist eine umlaufende, vorzugsweise im Wesentlichen zylindrische Seitenwand 64 und ein die Seitenwand 64 oben verschließendes Dach 68 auf. Die Seitenwand 64 weist an ihrem unteren Ende nach außen weisende Rasthaken 66 auf, so dass der Hohlkörper 62 in eine entsprechende Durchgangsöffnung 36 im Deflektor-Diffusor-Bauteil eingerastet werden kann. Hierzu kann der Seitenwandabschnitt 38 Axialschlitze aufweisen (nicht dargestellt). Die Seitenwand 64 weist zwei sich gegenüberliegende Löcher 64a, 64b auf. Das Zugelement 80 ist durch diese beiden Löcher 64a, 64b geführt, so dass ein Endabschnitt 82 des Zugelementes 80 durch den Hohlkörper 62 hindurch verläuft. Das zweite Ende des Zugelementes 80 ist verdickt ausgeführt (Bezugszeichen 88) und befindet sich außerhalb des Hohlkörpers 62. Hierbei ist der Durchmesser des verdickten Endes so ausgeführt, dass er größer als das benachbarte Loch 64a ist, wodurch das Zugelement 80 am Hohlkörper 62 und somit am Halteteil 60 gehalten ist. Andere Befestigungsmöglichkeiten, wie ein Verknoten, Verkleben, Verschweißen oder dergleichen wären ebenfalls möglich. Das verdickte Ende 88 kann im konkret gezeigten Ausführungsbeispiel einstückig mit dem übrigen Zugelement gebildet sein, beispielsweise durch thermisches Umformen, oder es kann auch als separates Element, beispielsweise wie die Perle einer Perlenkette, ausgebildet sein.

With regard to the 4 to 9 is now on the structure of the holding part 60 with integrated separator and its assembly on the deflector-diffuser component 30 received. Here shows the 4 the detail D from the 1 and 2 :

• In the specific embodiment shown, there is a two-part holding part 60 with integrated separator. A corresponding two-part training is not necessary for the success according to the invention, nor is it absolutely necessary to place the separating device in the holding part 60 to integrate. However, the specific embodiment shown is very advantageous in terms of its ease of installation: the holding part 60 with integrated separating device (hereinafter only from the holding part 60 the speech) has a hollow body 62 and one in the hollow body 62 protruding component 70 which is a pyrotechnic charge 74 carries on (in the geometry shown, the component protrudes 70 from below into the hollow body 62 ). The hollow body 62 has a circumferential, preferably substantially cylindrical side wall 64 and a the sidewall 64 roof closing at the top 68 on. The side wall 64 has outward-facing locking hooks at its lower end 66 on so the hollow body 62 in a corresponding through opening 36 can be snapped into the deflector-diffuser component. For this purpose, the side wall section 38 Have axial slots (not shown). The side wall 64 has two opposing holes 64a . 64b on. The tension element 80 is through these two holes 64a . 64b led so that an end section 82 of the tension element 80 through the hollow body 62 runs through. The second end of the tension element 80 is thickened (reference number 88 ) and is located outside the hollow body 62 , Here, the diameter of the thickened end is designed so that it is larger than the adjacent hole 64a is what the tension element 80 on the hollow body 62 and thus on the holding part 60 is held. Other Fastening options such as knotting, gluing, welding or the like would also be possible. The thickened end 88 can be formed in one piece with the rest of the tension element in the embodiment specifically shown, for example by thermal shaping, or it can also be formed as a separate element, for example like the pearl of a pearl necklace.

How to 4 can see immediately, is the end section 82 of the tension element 80 above that of the component 70 carried pyrotechnic charge 74 and there is a direct connection between the space in which the pyrotechnic charge is received and the cavity of the hollow body 82 , Now the pyrotechnic charge 74 fired on an external signal, like this in 5 is shown, the hot combustion gases hit the pyrotechnic charge 74 on the end section 82 of the tension element 80 , which then melts or sublimates, like this in 6 is shown. This leads to a severing of the tension element 80 , whereupon this can no longer absorb tensile stress and thus the gas bag unit in the in 3 shown state passes (see also 7 ). In order to achieve this, there is at least the end section 82 of the tension element 80 Made of a correspondingly fusible / subilimatable material, such as polyethylene, it is preferred that at least the end section 82 is not woven. Of course it is possible that the entire tension element is made of the same material as the end section.

The two-part construction of the holding part shown 60 has the advantage that the component carrying the pyrotechnic charge 70 has to be assembled very late: First, it is the one with the tension element 80 connected hollow body 62 on the deflector-diffuser component 30 locked and only then is the component carrying the pyrotechnic charge 70 from the outside through a through opening 27 in the case bottom in the hollow body 62 introduced with which it can be glued or locked, for example. When fully assembled, the component inserted into the cavity and carrying the pyrotechnic charge secures the hollow body against unlatching of the deflector-diffuser component. In this state there is also an almost closed cavity (except for the holes 64a . b ), so that there are practically no open flames within the gas cask.

The 8th and 9 show a variation of what has just been described: Here the hollow body points 62 only one hole, namely in the roof 68 of the hollow body 62 , This hole has the reference symbol here 68a , The thickened end 88 of the tension element 88 is located inside the hollow body 62 , In this embodiment, it is imperative that the thickened end 88 of the tension element 80 consists of a meltable or sublimable material, in particular a thermoplastic.

The 10 shows a further variation of the holding part 60 With integrated separating device: Here is the end section 82 in several layers 82a . 82b and 82c through the cavity of the hollow body 62 over the pyrotechnic charge 74 guided, so that a kind of "mechanical series connection" is created. It only has to be one of the locations 82a to 82c melt or sublime, in order to change the state of the tension element 80 to reach. In this way, the functional reliability can in principle be increased.

The 11 shows another variation. Here is the end section 82 formed by a large number of thin filaments, which lie between two end pieces 86a . 86b extend. The number and thickness of the filaments is chosen so that the end section 82 the same tensile strength as the rest of the tensile element 80 reached (the end section 82 is also part of the tension element here according to the definitions made). By dividing the tension element 80 in a plurality of thin filaments the melting or sublimation speed is increased, which can lead to an even higher reaction speed.

In the exemplary embodiments just described, the heat generator, the actuation of which leads to a melting / sublimation of a section of the tension element, is formed by a pyrotechnic charge. In an alternative embodiment, but not shown in the figures, this heat generator can also be replaced by an electrical heat generator, in particular a heating wire, with which a section of the tension element is at least indirectly in thermal connection.

The invention has been described on the basis of exemplary embodiments in which the control device is used to control a ventilation device. However, the control devices described can also be used to influence the geometry of the gas bag; in this case the first end of the traction element is connected to the gas bag.

LIST OF REFERENCE NUMBERS

10

airbag

12

vent

14

grommet

20

casing

22

caseback

23

Opening in the case back

25

inflator

27

Through opening in the case bottom

30

Deflector-diffuser component

32

bottom section

34

raised area

36

Through opening in the deflector-diffuser component

38

Sidewall portion

39

diffuser section

60

holding part

62

hollow body

64

Side wall

64a, b, c, d

Hole in the side wall

66

latch hook

68

top, roof

68a

Through opening in the roof

70

Component carrying pyrotechnic charge

74

pyrotechnic charge

76

ignition cable

80

tension element

82

end

82a, b, c

documents

84

filaments

86

cut

88

thickened end

Claims (5)

Airbag unit with an airbag (10) enclosing at least one chamber, a carrier component, in particular a housing (20), for receiving the gasbag (10), an inflator held on the carrier component for filling the at least one chamber and a control device for actively influencing the geometric shape the gas bag (10) filled with gas and / or the ventilation of the at least one chamber, the control device comprising at least one pulling element (80) extending from a first end to a second end, the first end of which is connected to the gas bag (10) or a ventilation device is connected and the second end of which, in an initial state, is at least indirectly connected to the carrier component, and a separating device which, in response to an external signal, separates the second end of the tension element (80) from the carrier component or cuts the tension element (80), the separating device comprising a pyrotechnic charge (74), which on the outer Signal acts directly thermally on the tension element (80), so that it melts in sections or loses its strength, the pyrotechnic charge (74) being in flow communication with a cavity through which a section of the tension element (80) runs, characterized that the section of the tension element (80) on which the pyrotechnic charge (74) acts consists of a plurality of filaments (84) extending parallel to one another and extending between two end pieces (86a, 86b). Airbag unit after Claim 1 , characterized in that an at least two-part holding part (60) is provided with an integrated separating device. Airbag unit after Claim 2 , characterized in that the at least two-part holding part has a hollow body (62), through the cavity of which an end section of the tension element (80) runs and a component (70) which carries the pyrotechnic charge (74) and projects into the cavity. Airbag unit after Claim 3 , characterized in that the hollow body (62) is latched to the carrier component. Airbag unit after Claim 4 , characterized in that the component (70) carrying the pyrotechnic charge was pushed into the hollow body (62) after the hollow body (62) had latched onto the carrier component.

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