RELATED APPLICATIONS

This application corresponds to PCT/EP2019/065969, filed Jun. 18, 2019, which claims the benefit of German Application No. 10 2018 115 062.8, filed Jun. 22, 2018, the subject matter of which are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

The invention relates to an airbag unit, especially a head side airbag unit, comprising an airbag folded or rolled into an elongate package as well as a wrapping holding the package in the folded state.

Said airbag units are installed in vehicles as so-called curtain-like head side airbag units. Said head airbag units in the inflated state cover at least a large part of a side window or of the side windows of the front occupant and of the rear occupant sitting behind in a row. The airbags protect against a side impact and are folded or rolled lengthwise, i.e. the package has longitudinal folds or a roll axis extending in parallel to the longitudinal direction of the airbag. In other words, the length of the package corresponds to the length of the spread airbag, measured in the longitudinal vehicle direction (related to the mounted state). Usually said airbag units are installed along the roof rail above the side windows and, where necessary, also along one or two vehicle pillars beneath a lining. The wrapping holds the airbag in its folded or rolled state, thus facilitating assembly.

However, there are particular mounting situations in which the package is difficult to be mounted in an elongate form, i.e. in its stretched length, e.g. because there is little space provided in the area of a vehicle pillar. In that case, according to the invention said longitudinal end of the package including the wrapping surrounding the package which surrounds the package like a sausage casing is folded back in U-shape at a bending point. When the wrapping tears due to the internal pressure within the airbag in the case of release, the fold-back airbag portion turns back to its home position, i.e. its non-bent position, and covers an additional portion of the vehicle so as to offer safety even in this area.

What is important for quickly deploying and returning the airbag in the area of the fold-back end is a rapid gas flow through the interior of the package into said fold-back package portion. Usually this is impeded by the fact that the fold-back package portion is fastened at least temporarily via fasteners to the remaining airbag unit. It is the object of the invention to provide an airbag unit which can be mounted in a more variable manner.

This is achieved in an airbag unit of the aforementioned type in that a longitudinal end of the package including the surrounding flexible wrapping is folded back at a bending point while forming a U-shape, wherein said U-shape is formed by a fold-back portion of the airbag unit with a fold-back package portion and the surrounding wrapping as well as a remaining airbag unit, and wherein the wrapping has a given first tearing line which extends over the length of the airbag unit and via which the airbag leaves the wrapping during deployment, the wrapping having an additional given second tearing line in the area of the bending point.

In previous elongate airbag units, the wrappings included only one tearing line which usually extended over the total length of the airbag package. The invention provides another tear line that provides weakening in the area of the bending point. Said weakening may help to widen the airbag more easily in the area of the bending point, for the wrapping opens more easily than in the state of the art. The flow passage forming for the inflowing gas in the interior of the not yet or hardly deployed airbag may be increased in the area of the bending point already in the initial state of the inflating operation so that gas may flow into the fold-back package portion more quickly than before, which results in rapid deployment thereof and in tearing of the first tearing line.

The second tearing line preferably extends on wall portions of the wrapping facing each other. By folding back the longitudinal end of the package two portions of the wrapping are adjacent to each other or are juxtaposed, and in said wall portions facing each other then the second tearing line is provided.

The second tearing line should extend in the direction of longitudinal extension of the package, especially exclusively in the direction of longitudinal extension of the package, i.e. along the folding lines or along the roll axis. This provides for even quicker tearing behavior.

The second tearing line moreover may be circumferentially spaced apart from the first tearing line over its entire length. This ensures the wrapping to be opened at the first and second tearing lines independently of each other.

The second tearing line should extend over at least 60%, especially over at least 75% of the length of the fold-back package portion so as to allow for a gas flow up to the longitudinal end of the airbag.

Furthermore, it is of advantage when the second tearing line extends from the bending point over the same length along the portions of the wrapping starting from the bending point. In this way it is to be achieved that on one side the deploying airbag can peel the wrapping further off at one package portion in the area of the second tearing line than at the other package portion.

In order to enable the airbag to leave the airbag at the first tearing line over the entire length thereof and to spread downwards in the direction of the vehicle bottom, the second tearing line should extend starting from the bending point only over a partial length of the fold-back wrapping, i.e. not over the entire wrapping. This is to ensure that the end of the airbag leaves the wrapping at the first tearing line and not completely at the second tearing line only.

The airbag unit according to the invention may also comprise an inflator which is fluid-coupled to the airbag at the central third of the longitudinal extension of the folded airbag unit. The inflator then generates gas which spreads from said central third preferably in opposite directions forwards and backwards.

There may be provided a fastener by which the fold-back portion of the airbag unit is fastened to the remaining airbag unit or, more generally, is fixed relative to the remaining airbag unit. Here, for example, a type of strip or clamp may be provided which is then fastened to the vehicle. It is an alternative option that the fold-back portion of the wrapping is fastened to the remaining portion of the wrapping. The mounting position is defined within narrow limits by the fastener.

SUMMARY OF THE INVENTION

The airbag of the airbag unit according to the invention especially is a curtain-like head side airbag for covering at least part of a side window of a dedicated vehicle, especially a joint airbag for front and rear occupants, i.e. the airbag extends over the dedicated side windows of the front and rear passengers.

The wrapping in particular is a flexible tube made from e.g. textile material, wherein the wrapping may be manufactured e.g. by being laid around the package and then being stitched up.

The first and/or second tearing line(s) may be a perforation of the wrapping or a tear seam in the wrapping.

In order to render the time succession of opening operations of the wrapping predeterminable, the wrapping is preferably less stable at the second tearing line than at the first tearing line at least in the portion extending next to the second tearing line. Thus, the wrapping breaks at the second tearing line ahead of the portion of the first tearing line extending next to the second tearing line, viz. extending within the same longitudinal portion as the first tearing line.

