VEHICLE OCCUPANT PROTECTION SYSTEM AND METHOD FOR ACTIVATING A VEHICLE OCCUPANT PROTECTION SYSTEM

Abstract

In a vehicle occupant protection system, a gas generator assembly (12) comprises at least one separate support (24) mountable to the vehicle and at least two gas generators (16, 18) which are tightly mounted on the support (24). A control unit (22) determines the times of activation of the at least two gas generators (16, 18) simultaneously or time-delayed in order to be able to activate one of the gas generators (16, 18) already in advance of a possibly imminent crash situation so that the airbag (14) is filled in such a way that it starts an interaction with an associated vehicle occupant which moves the vehicle occupant by a predetermined distance.

Claims

1. A vehicle occupant protection system comprising at least one airbag (14) which can be filled by means of a gas generator assembly (12), wherein the gas generator assembly (12) comprises at least one separate support (24) mountable to the vehicle and at least two gas generators (16, 18) manufactured separately from each other and each having a separate outer housing which are tightly mounted on the support (24), and wherein both gas generators (16, 18) supply, individually and/or jointly, filling gas for the same airbag (14), and comprising a control unit (22) which determines the times of activation of the at least two gas generators (16, 18), wherein the times can be determined simultaneously or time-delayed.

2. The vehicle occupant protection system according to claim 1, wherein the support (24) is designed such that the longitudinal directions (L.sub.1, L.sub.2) of the at least two gas generators (16, 18) on the support (24) include an angle (a) between 0° and 180°, specifically between 0° to 45°, with each other.

3. The vehicle occupant protection system according to claim 1, wherein the at least one airbag (14) is a side airbag and particularly the gas generator assembly (12) is mounted on a seat frame (33) of a vehicle seat.

4. The vehicle occupant protection system according to claim 1, wherein the support (24) includes a central land (25) having two concave seats (26) provided on opposite sides of the central land (25), with each of the gas generators (16, 18) being inserted in one seat (26) and the seats (26) being adjusted to the outer contour of the respective gas generator (16, 18).

5. The vehicle occupant protection system according to claim 4, wherein the seats (26) are circumferentially closed.

6. The vehicle occupant protection system according to claim 1, wherein the support (24) includes a fastener (36) via which the gas generator assembly (12) is fixed to the vehicle.

7. The vehicle occupant protection system according to claim 1, wherein the gas generators (16, 18) are fixed to the support (24) via strips (28).

8. The vehicle occupant protection system according to claim 1, wherein the support (24) is welded to at least one of the gas generators (16, 18) and/or includes at least one fastening hole (40) which is aligned with a fixing element on a circumferential wall of one of the gas generators (16, 18).

9. The vehicle occupant protection system according to claim 1, wherein the support (4) comprises a diffuser portion (46).

10. A method of activating a vehicle occupant protection system according to claim 1, comprising the steps of: detecting a possibly imminent crash situation, activating one of the gas generators (16, 18) already in advance of the detected possibly imminent crash situation so that the airbag (14) is filled in such a way that it starts an interaction with an associated vehicle occupant which moves the vehicle occupant by a predetermined distance, and activating the other gas generator (18, 16) in case the crash situation does really occur.

Description

[0045] In the following, the invention shall be described in greater detail by means of plural embodiments with reference to the attached drawings, wherein:

[0046] FIG. 1 shows a schematic perspective view of a gas generator assembly of a vehicle occupant protection system according to the invention as set forth in a first embodiment for carrying out a method according to the invention;

[0047] FIGS. 2 and 3 show different supports of the gas generator assembly of FIG. 1;

[0048] FIG. 4 shows a support of a gas generator assembly according to a further embodiment;

[0049] FIG. 5 shows the support of FIG. 4 comprising two gas generators inserted in the same;

[0050] FIG. 6 shows a schematic sectional view of a gas generator assembly according to another embodiment;

[0051] FIGS. 7 and 8 show schematic views of a gas generator assembly according to yet another embodiment; and

[0052] FIGS. 9 to 11 show schematic views of a gas generator assembly according to yet a further embodiment.

[0053] FIG. 1 illustrates a vehicle occupant protection system 10 comprising a gas generator assembly 12 supplying filling gas for an airbag 14 (indicated in FIG. 1).

[0054] The gas generator assembly 12 in this example comprises two individual gas generators 16, 18 manufactured separately from each other and each having a separate outer housing. Hereinafter, they will also be referred to as first and second gas generators 16, 18.

[0055] All gas generators 16, 18 of the gas generator assembly 12, more precisely the igniters 20 thereof, are connected to a control unit 22 that is designed to activate the gas generators 16, 18 by transmitting an electric signal to the igniters 20 thereof.

[0056] The gas outlet areas of all gas generators 16, 18 of the gas generator assembly 12 are located inside the airbag 14 and supply filling gas for said airbag 14.

[0057] The control unit 22 is designed so that it presets the activation times of the two gas generators 16, 18 individually, wherein the times can be fixed simultaneously or time-delayed and can also be determined depending on a current driving situation of the vehicle in which the vehicle occupant protection system 10 is installed.

[0058] The two gas generators 16, 18 in this case are tubular gas generators (i.e., gas generators the longitudinal extension of which along a longitudinal direction L1, L2 is larger than their diameter normal to said longitudinal direction). The gas generators 16, 18 can be identical or, as shown here, have different designs and, accordingly, can differ both by the amount of filling gas which they can provide and by their type, their length, their diameter, the arrangement of their gas outlet areas as well as other features.

[0059] The combination of the two gas generators 16, 18 is selected so that, with respect to their capacity, specifically their amount of filling gas, they allow a two-stage filling of the airbag 14 which is adapted to the vehicle conditions, for example concerning the position and the volume of the airbag 14 as well as the possible sitting positions of the vehicle occupant in a vehicle seat with which the airbag 14 is associated.

[0060] For example, the first gas generator 16 is designed so that it supplies a larger amount of filling gas than the second gas generator 18. In this example, the first gas generator 16 also has a larger diameter than the second gas generator 18, the diameters amounting to, e.g., 20 mm and 25 mm.

[0061] A possible scenario for activating the gas generators 16, 18 of the gas generator assembly 12 is as follows: Sensors 23 inside the vehicle which communicate with the control unit 22 provide information about a detected possibly imminent crash situation which might develop for the vehicle (so-called pre-crash detection).

[0062] Where necessary, further data are detected by other sensors, for example about a position of a vehicle seat and the backrest thereof and a current position of the vehicle occupant in the particular vehicle seat, and are equally transmitted to the control unit 22.

[0063] The control unit 22 determines proper times for the activation of the two gas generators 16, 18.

[0064] Initially, even before the crash situation actually occurs, the first gas generator 16 is activated so that the filling gas thereof inflates the airbag 14 up to a first volume. The airbag 14 gets in contact with and exerts a force upon the vehicle occupant, the force moving the vehicle occupant to an appropriate position and out of a dangerous zone. In so doing, the airbag 14 possibly is not inflated up to its maximum filling volume and/or internal pressure.

[0065] If the crash situation does not occur, the second gas generator 18 is not activated and the filling gas escapes through gas outlet openings (not shown) from the airbag 14.

[0066] If, however, a crash situation actually develops, upon occurrence of the crash situation also the second gas generator 18 is activated and the filling gas thereof is introduced to the airbag 14 so as to (re-) fill the airbag 14 up to the complete intended filling volume and/or internal pressure so that the vehicle occupant can be safely cushioned.

[0067] The gas generator assembly 12 can be used for this purpose like a conventional two-stage gas generator.

[0068] The two gas generators 16, 18 are mechanically interconnected in the gas generator assembly 12 via one or more supports 24. Here, two supports 24 are provided which are arranged spaced apart from each other along the longitudinal directions L1, L2 of the gas generators 16, 18.

[0069] As shown in FIGS. 2 and 3, each of the supports 24 has a suitable shape adapted to the current installation situation in the vehicle. The support(s) 24 is/are made of a suitable synthetic material or metal and may have identical or different shapes.

[0070] In this embodiment, each of the supports 24 has a central land 25 at which a seat 26 is formed on each of opposite sides. Each of the seats 26 takes a concave shape and is adapted to the outer contour and, specifically, to the diameter of the respective gas generator 16, 18 which is laterally inserted in the seat 26.

[0071] The radii of the seats 26 may be located on a straight line (see FIG. 2) or may form straight lines offset against each other (see FIG. 3). This can be individually adjusted to the given installation situation.

[0072] In the example of FIG. 1, the two gas generators 16, 18 are disposed in the gas generator assembly 12 such that the longitudinal directions L1, L2 thereof are in parallel to each other. This is not mandatory, however. The longitudinal directions L1, L2 can also enclose an angle a between 0° and 180°, specifically between 0° and 45°, wherein the longitudinal directions L1, L2 need not essentially be located in the same plane.

[0073] The arrangement of the gas generators 16, 18 relative to each other is clearly predefined by the shape of the supports 24, particularly the position and the alignment of the seats 26.

[0074] For example, an irregularly shaped holding space in a side bolster can be utilized to arrange the gas generator assembly 12. In this case, the airbag 14 is a side airbag which deploys out of the backrest between the vehicle seat and, e.g., an outer wall of the vehicle.

[0075] In this example, the igniters 20 of both gas generators 16, 18 are close to each other and, with respect to the longitudinal directions L1, L2, also at the same position so as to facilitate both the electric contacting and the sealing against the airbag 14. This means that the shorter of the two gas generators, the gas generator 18 in this case, does not protrude as far into the airbag 14 as the gas generator 16 does.

[0076] FIGS. 4 and 5 illustrate an example of a support 24 in which the seats 26 are not open to the side, but are circumferentially closed so that they surround the complete circumference of the two gas generators 16, 18. Such support 24 is applied, for example, in the area of the igniter 20 (see FIG. 5) and, at the same time, can be used for sealing against an inflation mouth of the airbag 14.

[0077] The support 24 may be manufactured in one piece, with the gas generators 16, 18 being inserted into the respective seats 26 along their longitudinal directions L1, L2, or may consist of two parts, as indicated in FIG. 4, which are assembled around the gas generators 16, 18 at a parting line 27.

[0078] It is generally possible to freely combine all different supports 24 shown in a gas generator assembly 12 at a skilled person's discretion so as to obtain the desired arrangement of the two gas generators 16, 18 as well as a desired fixation on the vehicle.

[0079] Basically, it is also possible to design supports 24 which can combine three or more gas generators at the same time in one single gas generator assembly 12 to achieve a flexible multi-stage ignition behavior.

[0080] Inside the gas generator assembly 12, the gas generators 16, 18 and the supports 24 are held together by strips 28, for example (see FIGS. 1, 6 and 9), with one strip 28 being provided for each support 24. The strips 28 in this case are straps made of steel which are provided with a buckle 30 and which, after being tightened, retain the gas generators 16, 18 safely in their distinct position at the supports 24.

[0081] The supports 24 have suitable geometries, for example, to retain the strips 28 at the intended position (see recess 32 in FIG. 9, for example).

[0082] For mounting the gas generator assembly 12 to the vehicle, such as to a seat frame 33 of a vehicle seat, for example fastening bolts 34 provided on one of the gas generators 16, 18 can be utilized, as this is conventionally done when mounting a single gas generator (indicated in FIG. 7).

[0083] FIG. 6 illustrates a variant in which a fastener 36 for mounting fixed to the vehicle, in this case a fastening bolt, is integrated in the support 24.

[0084] In this example, the fastener is also used for fixing the strip 28 to the support 24 by placing openings 37 in the end portions of the strip 28 over the fastening bolt.

[0085] FIGS. 7 and 8 illustrate another variant of the supports 24. In this case, each of the supports 24 is made of a metal strip bent in V-shape the one end of which is tightly fixed to one of the gas generators, in this case the first gas generator 16, by a welded connection 38. The other end includes a fastening hole 40 through which one of the fastening bolts 34 of the second gas generator 18 is inserted and secured by a nut 42. In this example, the fastening bolts 34 of the first gas generator 16 are used to mount the gas generator assembly 12 to the vehicle (not shown).

[0086] FIG. 8 also shows that a diffuser 44 can equally be mounted to one of the fastening bolts 34 of the second gas generator 18.

[0087] FIGS. 9 to 11 illustrate an embodiment in which a diffuser portion 46 for the second gas generator 18 is integrated in one of the supports 24.

[0088] FIG. 10 shows a section along the line X-X and FIG. 11 shows a section along the line XI-XI of FIG. 9.

[0089] In addition, a diffuser is mounted on the fastening bolts 34 of the first gas generator 16.

[0090] In this case, a respective strip 28 is utilized to fasten the second gas generator 18 to the support 24.

[0091] FIGS. 9 and 10 also illustrate the recess 32 for the strip 28 that connects the strip to the support 24 and secures it against displacement.

[0092] In this case, too, the fastening bolts 34 of the first gas generator 16 are used for fixing the gas generator assembly 12 to the vehicle.