Side airbag device

Abstract

The invention relates to a side airbag device (1) for a,achment to an outer side of a vehicle seat or an inner side of a vehicle structure, comprising -a gas bag (2) with -a first gas chamber (3) which, in the inflated state, is arranged between the vehicle structure and the vehicle seat, and -a second gas chamber (4) which, in the inflated state, is arranged between the vehicle seat and the first gas chamber (3), wherein -the first gas chamber (3) is arranged to be blown out in a pre-accident situation, and -the second gas chamber (4) is arranged to be blown out in an accident situation; characterized in that -the first gas chamber (3) in the inflated state has a larger volume than the second gas chamber (4) in the inflated state.

Description

[0001] Side airbag device

[0002] The present invention relates to a side airbag device with the features of the preamble of claim 1.

[0003] Various side airbag devices with a gas bag with two gas chambers are known from the prior art, in which a first gas chamber is first inflated, thereby tearing open a tear seam in the vehicle seat and, in the further course of inflation, serves to pre-direct the occupant.

[0004] Subsequently, a second gas chamber is inflated in an early phase of an accident that has actually occurred, which protects the occupant from a collision with the inner side structure of the vehicle. The first gas chamber is used to pre-direct the occupant by moving them to a position on the vehicle seat that is as central as possible, away from the inner side structure of the vehicle, so that they can subsequently be better protected by the second gas chamber when the actual accident occurs. Here, the requirements on the part of the vehicle manufacturer go so far, for example, that the occupant must be displaced at least 80 mm towards the center of the vehicle in a time span of 150 ms before the actual accident occurs (t=0).

[0005] The object of the invention is to provide an improved side airbag device with a gas bag with two gas chambers, which is intended in particular to enable improved pre-direction of the occupant before the actual accident occurs and, in addition, an improved restraint of the occupant in the accident.

[0006] The object is solved by a side airbag device comprising the features of claim 1. Further preferred embodiments of the invention can be found in the subclaims, the figures and the associated description. In accordance with the basic idea of the invention, it is proposed that the first gas chamber in the inflated state has a larger volume than the second gas chamber in the inflated state. Turning away from the previous practice of designing the first gas chamber to be fundamentally smaller than the second gas chamber, as this "only" serves to pre-direct the occupant, the solution according to the invention takes a fundamentally new approach by designing the first gas chamber in such a way that, when inflated, it deliberately has a larger volume than the second gas chamber, thereby pushing the occupant considerably further towards the center of the vehicle and thus creating a much larger free space into which the second gas chamber, which is smaller in volume, is then inflated. This deliberately reverses the conditions and the first gas chamber takes on a much more important function for the overall restraint characteristics by displacing the occupant. Since the free space created by the first gas chamber is significantly larger than before and, in particular, larger than the volume of the second gas chamber, the second gas chamber, which is crucial for the restraint of the occupant in the accident, can be inflated more easily to its optimum geometry, which in turn can improve the actual restraint of the occupant in the subsequent accident. The overall function of the first gas chamber in the safety device is thus significantly enhanced.

[0007] It is further proposed that the first gas chamber is dimensioned such that, when inflated, it has 1.1 to 1.5 times the volume of the second gas chamber when inflated.

[0008] A particularly simple and inexpensive safety device can be realized in that the gas bag is designed in three layers, and the first gas chamber is formed by a cavity between a first layer facing the vehicle seat and a middle second layer, and the second gas chamber is formed by a cavity between a third layer facing the vehicle structure and the middle second layer. The gas bag with the two gas chambers can thus be designed very cost-effectively and compactly, firstly by using the middle layer for both gas chambers and secondly by simplifying the sewing process, as the number of layers is reduced to a minimum. The three layers or just two of the three layers can be produced in a prefabrication process in a one-piece weaving process or joined in a sewing process. This advantage is particularly utilized in that the first layer, the second layer and the third layer are sewn together in a common seam, at least in sections, whereby the manufacturing costs of the side airbag device can be reduced with respect to the sewing.

[0009] The larger volume of the first gas chamber can be achieved particularly easily by the first layer having a larger surface area than the second and third layers. The first layer faces the vehicle seat and is thus inflated starting from the middle layer in the direction of the vehicle seat, so that the gas bag unfolds to the larger volume when inflated with the first layer with the larger surface area and displaces the occupant towards the center of the vehicle. The gas bag can support itself with the first gas chamber on the inner side of the vehicle structure while it moves the occupant towards the center in accordance with the vehicle manufacturer's requirements. For this purpose, the larger volume of the first gas chamber is deliberately used to move the occupant further towards the inside of the vehicle with a greater impulse.

[0010] It is also proposed that the first layer is folded back on itself in a fold. By folding the first layer back towards the fold, the first layer can be folded back into an area that corresponds to the second layer and the third layer, despite its larger area, so that the gas bag can then be rolled or folded into a compact package more easily with the three layers lying on top of each other.

[0011] It is further proposed that the first layer is fixed in two opposite edge sections of the fold by a suitable connection to the fold. The first layer is thus also fixed to the fold in the region of the edge sections during the inflation process of the first gas chamber, so that it has a geometry which does not change during inflation in the region of these edge sections. This unchangeable geometry preferably corresponds to the geometry of the second layer and the third layer, provided that these are sewn together, for example, in a common seam. It is further proposed that the first layer is not fixed to the fold in a central section of the fold between the opposing edge sections. The first layer is deliberately not fixed to the pleat in the middle section of the pleat, so that the pleat can deliberately unfold when the first gas chamber is inflated and the volume of the first gas chamber is thereby increased.

[0012] It is further proposed that the first layer in the fold is folded back on itself over a width of 15 to 60 mm, preferably over a width of 30 to 40 mm. The proposed dimensioning of the fold makes it particularly easy to achieve the larger volume of the first gas chamber proposed according to the invention and the resulting greater displacement of the occupant towards the inside of the vehicle.

[0013] It is further proposed that a valve opening is provided in the central second layer, which allows the gas to flow from the first gas chamber into the second gas chamber during inflation of the second gas chamber. Through the proposed valve opening, the gas can deliberately flow over from the first gas chamber into the second gas chamber during the inflation of the second gas chamber, so that, firstly, the inflation of the second gas chamber is not slowed down by a back pressure exerted on the second middle layer by the first gas chamber, or this effect is at least reduced, and, secondly, the inflation of the second gas chamber is supported by an additional gas flow.

[0014] Furthermore, it is proposed that a first gas generator is provided, which is fl uidica I ly connected or connectable to the first gas chamber, and a second gas generator is provided, which is fluidica I ly connected or connectable to the second gas chamber. By inflating the two gas chambers with two different gas generators, the inflation characteristics of the two gas chambers can be individually improved, and the gas line can be simplified as such, since no flow connections to be opened need to be provided with regard to the gas flow to be introduced. It is further proposed that the first gas generator is a hybrid gas generator. Hybrid gas generator comprise a first gas volume under very high pressure and a pyrotechnical propellant. When activating the hybrid gas generator a very large first gas volume is released in a first phase without any chemical reaction releasing the gas volume of the pressurized gas volume. Furthermore, a second gas volume is released by the activation of the pyrotechnical propellant, which is added to the first gas volume and heats the first gas volume. The advantage in using the hybrid gas generator can be seen therein, that a gas volume with a high pressure and a large volume may me generated for a longer time period, by which the first chamber may be inflated to a large volume for a longer time period. Thereby the advantages of both types of gas generators can be combined by using a hybrid gas generator, wherein the first gas volume may be generated very quick by releasing the pressurized gas, and the second gas volume adding the first gas volume is generated by a smaller pyrotechnic propellant.

[0015] It is further proposed that the second gas generator is a pyrotechnic gas generator.

[0016] Pyrotechnic gas generators have the advantage that a gas volume can be generated during a chemical reaction to inflate the second gas chamber with the smaller volume in a very short time period. The second chamber is inflated thereby during the crash in a much shorter time period than the first gas chamber to a smaller volume and with a lower pressure, wherein it is used the free space provided by the first chamber. This has the advantage that the occupant, in his pre-directed position caused by the first gas chamber, is improved restraint against an impact on the inner side structure of the vehicle in the subsequent accident during lateral displacement in the second gas chamber.

[0017] The invention will now be described with reference to an embodiment of an airbag device with two gas generators according to the invention.

[0018] These show: Figure 1 a top view of a safety device with an airbag and two gas generators;

[0019] and

[0020] Figure 2 a sectional view of the airbag of Fig. 1 in sectional direction A-A; and

[0021] Figure 3 shows the gas bag with an inflated first gas chamber and an inflated second gas chamber in two different sectional views.

[0022] Figure 1 shows a side airbag device 1 according to the invention, which is designed to be fastened as a side airbag (SAB) in a side structure of a vehicle or at a seat structure of a vehicle seat by means of suitable fastening attachments. The side airbag device 1 is preferably attached to the outside of the seat structure, in a B-pillar or a door structure. Insofar as orientations or arrangements of the parts of the side airbag device in relation to the direction of travel, the vehicle seat, adjacent parts of the vehicle structure or the occupant are described in the invention, these relate to the installation state of the side airbag device 1 in the vehicle seat or in the vehicle structure and the orientation during activation of the side airbag device 1 while the inflation and the inflated state.

[0023] The side airbag device 1 comprises a gas bag 2 with two gas chambers 3 and 4, which can be seen in the sectional view of Fig. 2. Furthermore, the side airbag device 1 comprises a first gas generator 19 and a second gas generator 20, one of which is connected or can be connected to the first gas chamber 3 and one to the second gas chamber 4.

[0024] The airbag 2 is designed in three layers with a first layer 7, a second layer 8 and a third layer 9, wherein the attachment of the side airbag device 1 in the vehicle seat or on the vehicle structure is designed such that the first layer 7 is directed in the unfolded state towards the vehicle seat and the third layer 9 is directed in the unfolded state towards the vehicle structure. The first layer 7 has a larger surface area than the second and third layers 8 and 9 and is folded back on itself in a central section to form a fold 16, so that the first layer 7, despite its larger surface area, has an identical outer geometry with respect to the outer geometry of the second and third layers 8 and 9. The first layer 7 is connected to the second layer 8 via two seam connections 21 and 22, which may be sealed additionally by a silicon layer 10 and 11. It has been shown in trials, that a sealing of the seam connections 21 and 22 is not needed to achieve the necessary pressure relations in the gas chamber 3 und 4.

[0025] Furthermore, the first layer 7, the second layer 8 and the third layer 9 are joined together at least in sections in their edge sections via the seam connections 21 and 22 to form a three-layer composite, whereby the fold 16 is additionally fixed to the fold shape in its opposite edge sections 17 and 18. In the middle section between the edge sections 17 and 18, on the other hand, the fold 16 is not fixed in its fold shape, so that the superimposed sections of the first layer 7 only lie loosely on top of each other in the fold 16.

[0026] Furthermore, in the first gas chamber 3, two fabric sections 12 and 13 are fixed into a loop via seams 14 and connected to the second and third layers 8 and 9 via a seam connection 15. The fabric sections 12 and 13 fixed to form the loop form a diffuser 5, which is connected directly or indirectly to the flow outlet of the first gas generator 19.

[0027] When the side airbag device 1 is activated, the first gas chamber 3, formed by the cavity between the first layer 7 and the second or middle layer 8, is inflated to the geometry shown in the left-hand illustration of Figure 3, in which the second layer 8 or middle layer lies against the inside of the third layer 9 or is at least bulged out towards it. The volume of the first gas chamber 3 is increased unfolding the fold 16 in the area of the center section between the opposing edge sections 17 and 18 of the fold 16. The first gas chamber 3 is inflated either via the gas generator via the first gas generator 19, which is preferably designed as a hybrid gas generator. In this case, the first gas chamber 3 is pressurized to an internal pressure of approx. 20 to 30 kPa to a volume of 13 to 30 L, whereby the occupant, e.g. represented by a WSID dummy, can be displaced by 80 mm after 80 ms and by 120 mm after 150 ms after the start of activation of the first gas generators 19 towards the inside of the vehicle.

[0028] The first gas chamber 3 is deployed in a pre-accident phase approx. 200 ms before the defined time t=0 of the accident event. The first gas chamber 3 is inflated into the space between the occupant and the inner lateral vehicle structure by tearing open a seam in the seat, in the case of a seat-integrated attachment or a cover in a side panel of the vehicle structure, thus "clearing the way" for the subsequent inflation of the second gas chamber 4. The first gas chamber 3 has 1.1 to 1.5 times the volume of the second gas chamber 4, so that the first gas chamber 3 practically creates or maintains an oversized volume in the space between the occupants, into which the correspondingly smaller second gas chamber 4 is then inflated.

[0029] The second gas chamber 4 is formed by a cavity between the third layer 9 facing the occupant and the second or middle layer 8. The second gas chamber 4 is inflated by activating the second gas generator 20, which is preferably designed as a pyrotechnic gas generator or propellant. When the second gas chamber 4 is inflated, the second layer 8 is pushed in the direction of the first layer 7 until it rests against the inside of the first layer 7, as can be seen in the right-hand illustration of Figure 3. Since the third layer 9 has a smaller surface area than the first layer 7, the volume of the second gas chamber 4 is smaller, preferably by a factor of 1.1 to 1.5, than the volume of the first gas chamber 3.

[0030] By inflating the second gas chamber 4, the first layer 7 of the gas bag 2 loses its tension, and the fold 16 is pulled back together from the unfolded position into the folded shape, as can be seen in the right-hand illustration of Figure 3. The second gas chamber 4 with the smaller volume is inflated using the free space created by the first gas chamber 3 by displacing the second, middle layer 8 from the third layer 9 towards the first layer 7. The second gas chamber 4 is thus inflated in a process-safe manner with the lowest possible resistance, since no obstacles need to be displaced in order to deploy the second gas chamber 4 or since the deployment of the second gas chamber 4 cannot be impaired by obstacles. In order to prevent the movement of the second, middle layer 8 from being impeded by the pressure present in the first gas chamber 3, corresponding ventilation openings and / or tear seams can also be provided in the second layer 8, which, when opened, allow the gas flow from the first gas chamber 3 to flow over into the second gas chamber 4, whereby the inflation of the second gas chamber 4 is supported by an additional gas flow.

[0031] The second gas chamber 4 is designed with the second gas generator 20 so that it is inflated to a smaller gas volume with a lower internal pressure in relation to the first gas chamber 3. However, since it is deployed into an already created free space, it can be deployed into an optimal position for restraining the occupant, so that it can be utilized considerably better for restraining the occupant despite the smaller volume, thereby better protecting the occupant from an impact on the inner side structure of the vehicle. In this regard, the second gas chamber 4 is deliberately inflated to a lower internal pressure than the first gas chamber 3 and may have additional ventilation openings to allow the gas pressure to escape from the second gas chamber 4 and improve the immersion of the occupant in the second gas chamber 4. The first gas chamber 3 is inflated by the first gas generator 19 designed as a hybrid gas generator to a large volume with a high internal pressure for a longer time period, while the second gas chamber 4 is inflated by the second gas generator 20 designed a as pyrotechnical gas generator in a much shorter time period to a smaller volume and with a lower internal pressure. Since the second gas chamber 4 is inflated into a free space provided by the Inflation of the first gas chamber 3 in a previous step, the restraint effect of the second chamber 4 is essentially improved for the occupant. List of reference numbers

[0032] 1 Side airbag device 2 Gas bag

[0033] 3 First chamber

[0034] 4 Second Chamber

[0035] 5 Diffusor

[0036] 6 Receptacle

[0037] 7 First layer

[0038] 8 Second layer

[0039] 9 Third layer

[0040] 10 Siliconlayer

[0041] 11 Siliconlayer

[0042] 12 Fabric section

[0043] 13 Fabric section

[0044] 14 Seam

[0045] 15 Seam connection 16 Fold

[0046] 17 Edge section

[0047] 18 Edge section

[0048] 19 First gas generator 20 Second gas generator 21 Seam connection 22 Seam connection

Claims

Claims:

1. Side airbag device (1) for attachment to an outer side of a vehicle seat or an inner side of a vehicle structure, comprising-a gas bag (2) with-a first gas chamber (3) which, in the inflated state, is arranged between the vehicle structure and the vehicle seat, and-a second gas chamber (4) which, in the inflated state, is arranged between the vehicle structure and the first gas chamber (3), wherein-the first gas chamber (3) is arranged to be blown out in a pre-accident situation, and -the second gas chamber (4) is arranged to be blown out in an accident situation; characterized in that-the first gas chamber (3) in the inflated state has a larger volume than the second gas chamber (4) in the inflated state.

2. Side airbag device (1) according to claim 1, characterized in that-the first gas chamber (3) is dimensioned such that, in the inflated state, it has 1.1 to 1.5 times the volume of the second gas chamber (4) in the inflated state.

3. Side airbag device (1) according to one of claims 1 or 2, characterized in that-the gas bag (2) is constructed in three layers, and-the first gas chamber (3) is formed by a cavity between a first layer (7) facing the vehicle seat and a central second layer (8), and-the second gas chamber (4) is formed by a cavity between a third layer (9) facing the vehicle structure and the middle second layer (8).

4. Side airbag device (1) according to claim 3, characterized in that-the first layer (7), the second layer (8) and the third layer (9) are sewn together at least in sections in a common seam (21, 22).

5. Side airbag device (1) according to one of claims 3 or 4, characterized in that-the first layer (7) has a larger surface area than the second and third layers (8, 9).

6. Side airbag device (1) according to claim 5, characterized in that-the first layer (7) is folded back on itself in a fold (16).

7. Side airbag device (1) according to claim 6, characterized in that-the first layer (7) is fixed in two opposite edge portions (17, 18) of the fold (16) by a suitable connection to the fold (16).

8. Side airbag device (1) according to claim 7, characterized in that-the first layer (7) is not fixed to the fold (16) in a central section of the fold (16) between the opposing edge sections (17, 18).

9. Side airbag device (1) according to one of claims 6 to 8, characterized in that-the first layer (7) is folded back on itself in the fold (16) over a width of 15 to 60 mm, preferably over a width of 30 to 40 mm.

10. Side airbag device (1) according to one of claims 3 to 9, characterized in that-a valve opening is provided in the central second layer (8), which valve opening allows the gas to flow from the first gas chamber (3) into the second gas chamber (4) during inflation of the second gas chamber (4).

11. Side airbag device (1) according to one of claims 1 to 10, characterized in that-a first gas generator (19) is provided, which is fluidica I ly connected or connectable to the first gas chamber (3), and-a second gas generator (20) is provided, which is fluidica I ly connected or connectable to the second gas chamber (4).

12. Side airbag device (1) according to claim 11, characterized in that-the first gas generator (19) is a hybrid gas generator.

13. Side airbag device (1) according to claim 11 or 12, characterized in that-the second gas generator (20) is a pyrotechnic gas generator.

Images