The invention relates to a gas bag module for a vehicle occupant restraint system.
Such gas bag modules comprise a housing arranged on the vehicle, a gas bag arranged in the housing, a gas generator in flow connection with the gas bag and a covering connected with the housing, which closes the housing with respect to the interior of the vehicle and is opened after activation of the gas generator in order to permit the gas bag to emerge from the housing.
Gas bag modules of this type are known in the prior art in various embodiments. The covering is usually formed by a section of the steering wheel cover or of the instrument panel, which section is provided with an articulation region and a predetermined breaking point. After activation of the gas generator, an increasing pressure is produced in the interior of both the gas bag and the housing. Since the gas bag rests against the covering, the pressure increase results in the tearing of the predetermined breaking point. The covering is bent up at a high speed so that the gas bag can emerge from the housing and completely unfold.
One disadvantage of the prior art gas bag module is that there is a risk of the covering impacting a vehicle occupant when opening. Given the mass of the covering and the high speed in which it opens, a danger exists that a vehicle occupant may be injured if contacted by the covering. Another disadvantage of the prior art gas module is that the pressure, which must be built up inside the housing for tearing open the predetermined breaking point, is high.
The invention provides a gas bag module in which the risk of a vehicle occupant being contacted by the covering during opening of the covering is reduced and in which the covering opens at a lower pressure inside the housing.
This is achieved according to the invention by a gas bag module for a vehicle occupant restraint system, having a housing adapted to be mounted beneath a vehicle instrument panel, a gas bag arranged in the housing, a gas generator in flow connection with the gas bag, a retractable covering connected with said housing, and a device for displacing the housing in a direction opposite the vehicle interior during inflation of the gas bag. The covering extends over the housing and the covering and the instrument panel form a continuous surface. The covering opens after activation of the gas generator to permit the gas bag to emerge from the housing in a direction toward the vehicle interior. The displacement of the housing opens the covering.
This design allows movement of the housing together with the covering immediately after activation of the gas generator. The housing and the covering move in a direction away from the exterior of the instrument panel on the passenger side of the vehicle in such a way that the covering opens in a region which is not accessible to the vehicle occupant. Therefore, the risk of the vehicle occupant being contacted by the covering, which is opening at a high speed, is eliminated. The movement of the housing can take place in various ways; for example, a linear drive can be provided, which is activated by means of the pressure produced after ignition of the gas generator inside the housing or which is activated separately.
Displacement of the housing opens the covering. In this way, the covering opens virtually automatically after activation of the gas generator, so that the gas bag does not have to exert any pressure onto the covering to open the predetermined breaking point.