Air bag system for motor vehicles

In at least one embodiment, an air bag system comprises an air bag having an impact surface which in a non-inflated state is arranged in a housing located below the upper edge of a windowsill of a vehicle door. In an inflated state, at least part of the impact surface is positioned above the windowsill. There is a supporting surface for the air bag below the upper edge of the windowsill. The air bag defines a main chamber and a supporting chamber. The impact surface forms part of the main chamber. The supporting chamber, in an inflated state, is situated between the main chamber and the supporting surface and is supported at least in part by the supporting surface.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to PCT patent application WO2007/036336 filed Sep. 25, 2006 and DE 10 2005-046 267.7 filed on Sep. 27, 2005.

FIELD OF THE INVENTION

The invention relates to an air bag system for motor vehicles.

BACKGROUND OF THE INVENTION

In the state of the art, so-called side air bags for motor vehicles are known that are arranged either in the seat or in the lateral structure of the motor vehicle below the side window. Such side air bags are intended to protect the head and thorax of the occupant in the event of a side impact. As the head, and usually also part of the thorax of the occupant are above the windowsill of the side door, i.e. at the height of the side window, the side air bag is usually supported against the side window and most often, at least in part, against the B-pillar.

In convertibles and roadsters in particular—and to some extent in coupes as well—the B-pillar may be absent and the vehicle may be driven with the side windows rolled down. Consequently no supporting surface may be available at the height of the occupant's head.

The generic patent DE 100 24 293 A1 proposes arranging a housing, which accommodates a folded air bag a short distance below the windowsill and provides a supporting section by which the air bag is supported during expansion. However, further improvements may be desirable.

SUMMARY OF THE INVENTION

The present invention seeks to develop an air bag system such that protection of the occupant in the event of a side impact collision is further improved.

In at least one embodiment of the present invention, a housing that accommodates the non-inflated air bag is arranged below the windowsill in such a way that between the exit opening of the housing and the upper edge of the windowsill, there is a supporting surface for the air bag. This supporting surface can be part of the inner lining of the door or part of the housing. The air bag itself features a main chamber with an impact surface and a supporting chamber that is situated between the main chamber and the supporting surface. The main chamber is therefore not supported directly by the supporting surface, but only indirectly by the supporting chamber. In this way, a reasonably thick air bag is provided in the area of the supporting surface, so as to improve the supporting effect.

Dividing the air bag into two parts in the area of the supporting surface also provides the possibility of configuring the supporting chamber with a height that is lower than that of the main chamber, which, with the same gas generator performance, may lead to correspondingly faster filling, without having to accept losses with regard to the performance of the system. In addition, due to the configuration of the air bag system in accordance with the invention, it may be possible to position the supporting surface relative to the occupant so as to improve the retaining effect on the occupant, particularly through an early interfacing between the shoulder and head area of the occupant with the impact surface of the air bag.

DETAILED DESCRIPTION

FIG. 1shows a schematic view, from the inside, of the front-seat area of an open-topped or convertible vehicle. On the interior side of the door44below the upper edge44aof the windowsill, the housing40is arranged, which completely accommodates the air bag10in its non-inflated state.FIG. 1shows the state in which the air bag10is completely inflated, whereby a major part of the air bag is disposed above the upper edge44aof the windowsill. The housing40can be an integral part of the interior lining of the door or otherwise. A gas generator is also arranged (not shown inFIG. 1) proximate the housing (e.g. in or on the housing40).

The structure and functioning of the air bag system is illustrated inFIG. 2, which is a cross-sectional view along section A-A inFIG. 1. The air bag10features a main chamber14and a supporting chamber15, which are connected by means of filling chambers16. The housing40is arranged below the upper edge44aof the windowsill such that there is a supporting surface between the housing floor42, to which the air bag10is attached, and the upper edge44aof the windowsill. Notably, the supporting surface is formed in this example by a section of the internal or interior side43of the door. The supporting surface could also, for example, be part of the housing40(not shown) or some other vertically extending structure. The exit opening41of the housing is preferably arranged below the upper edge44aof the windowsill, so that at least one section of the supporting surface is situated below the exit opening41in the housing40.

As can be seen fromFIG. 2, the supporting chamber15is supported by the supporting surface. The main chamber14is in turn supported by the supporting surface. If the occupant is thrown onto the impact surface14aof the main chamber14, the force is transferred through the main chamber and the supporting chamber to the supporting surface (e.g. door44). In one example, this arrangement is positioned so that the impact surface14aof the main chamber14, originating from the housing floor42, inclines in the direction of the occupant so that the main chamber14interfaces with the occupant at an early point in time. In order to ensure sufficient support for the main chamber14, the supporting chamber15may be arranged outboard relative to the main chamber14in the installed state of the airbag system.

A gas generator30is in fluid communication with the air bag10. In one example, the outlet section34of the gas generator30protrudes into the main chamber14. The generating section32of the gas generator30is situated outside the air bag below the floor of the housing42. The incoming gas fills the main chamber14first, so that the inflated main chamber is filled early and is available to support the occupant. Gas continues to flow out of the main chamber14via the filling chambers16into the supporting chamber15, which, depending on the configuration of the filling chambers16, inflates at about the same time as the main chamber14, or after the main chamber14, and at least partially fills the space between the main chamber14and the supporting surface.

FIG. 3shows an extended first fabric layer of the air bag10. The entire air bag10can be sewn together of two congruent layers of fabric, or the air bag10can be formed in one piece, whereby two layers of fabric, which are also congruent, are interwoven in non-inflatable areas18. In the case of a sewn air bag, the two layers of fabric are sewn together, at least in sections, in the non-inflatable area18. The non-inflatable area18is shown as hatched. It can be seen that the filling chambers16may be configured as hose-like areas in a non-inflatable floor area19outside the filling chambers16, said floor area also featuring holes22for fixing the air bag10to the housing floor42. In this example configuration, manufacturing the air bag may be very simple and may not require significantly more effort and expense than a comparable single-chamber air bag. The air bag is filled by the gas generator, which may, for example, protrude through the inlet opening20in the main chamber.

In the installed state of the air bag, the floor area19is connected to the housing floor42, and the two chambers extend, in a folded, non-inflated state, in the direction of the exit opening41. The chambers can be folded jointly or independently of each other.

According to the principles of the present invention, the main and supporting chambers could be configured completely separately and filled by separate gas generators, which may however require additional work and expense as well as a greater need for space within the side structure of the motor vehicle.