BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an airbag according to the principles of the present invention;
FIG. 2 is a section view of the airbag of FIG. 1 along Plane A;
FIG. 3 is a detail view of an upper portion of the airbag of FIG. 2;
FIG. 4 is a front view of the airbag of FIG. 1 inflating beside a large vehicle occupant just prior to contact with the large vehicle occupant;
FIG. 5 is a front view of the airbag of FIG. 4 after contact with the large vehicle occupant;
FIG. 6 is a front view of the airbag of FIG. 1 inflating beside a small vehicle occupant just prior to contact with the small vehicle occupant;
FIG. 7 is a front view of the airbag of FIG. 6 after contact with the small vehicle occupant;
FIG. 8 is a side view of a second embodiment of the airbag according to the principles of the present invention;
FIG. 9 is a section view along line B-B of the airbag of FIG. 8;
FIG. 10 is an outer unstitched fabric for the two outer fabric layers of an airbag according to a third embodiment of the present invention;
FIG. 11 is an inner unstitched fabric for the two inner fabric layers of the airbag of FIG. 10; and
FIG. 12 is a section view of the airbag of FIG. 10.
DETAILED DESCRIPTION
Referring now to the drawings, an airbag embodying the principles of the present invention is illustrated in FIG. 1. The structure of the airbag according to a first embodiment in the form of a side airbag is now described with reference to FIGS. 1 to 3. As its primary components, the airbag includes three chambers, namely the main chamber 10, the pelvic chamber 20 and the auxiliary chamber 30 (see FIG. 1). The main chamber 10 and the pelvic chamber 20 serve to restrain a vehicle occupant, while the auxiliary chamber 30 primarily serves to regulate pressure within the main chamber 10. The main chamber 10 is generally arranged, upon inflation, adjacent to an upper body (i.e. thorax) area of a vehicle occupant (see FIGS. 4-7). Likewise, the pelvic chamber 20 is arranged adjacent to a pelvic area of a vehicle occupant.
As can best be seen from FIGS. 2 and 3, the auxiliary chamber 30 is sewn onto the main chamber 10 by means of seam areas 42. Furthermore, the main chamber 10 and the auxiliary chamber 30 are connected with each other by means of a connecting opening 14, so that exchange of gas can take place between the main chamber 10 and the auxiliary chamber 30.
Auxiliary chamber 30 is again itself formed in two pieces, of an inner chamber 32 with an inner fabric layer 32a and an outer chamber 36 with an outer fabric layer 36a (see FIG. 3). The aforementioned connecting opening 14 is a common opening between a fabric layer 10a of the main chamber 10 and the outer fabric layer 36a of the auxiliary chamber 30.
The inner chamber 32 and the outer chamber 36 are each basically tubular in form as can best be seen in FIG. 1. In this view, the outer fabric layer 36a is shown broken open in a certain area, so that the inner chamber 32 is visible. Inner chamber 32 and outer chamber 36 include a common front side 40 in which an outflow opening 35 is located, which connects the interior of the inner chamber 32 with the environment outside of the airbag.
A valve opening 34 is located in the inner fabric layer 32a, which connects the inner chamber 32 with the outer chamber 36 (see FIGS. 1 to 3). If the airbag can expand unhindered (this corresponds to the situation shown in FIGS. 1 to 3), the main chamber 10 is connected with the outside environment (i.e. gas can flow out of the main chamber into the environment). In this situation, a gas path is as follows: gas first flows from main chamber 10 through connecting opening 14 into outer chamber 36, from there through valve opening 34 into inner chamber 32 and from there through outflow opening 35 to the outside. Depending on the configuration of a gas generator (not shown) and the geometry of the airbag, a certain internal pressure is created in the main chamber 10.
The valve opening 34 and the connecting opening 14 can be in the form of holes in the respective fabric layers or gas-permeable fabric areas.
If a part of the outer fabric layer 36a is pressed against the valve opening 34, the valve opening 34 is completely or partly closed and the flow of gas from the main chamber 10 to the outside is throttled or completely blocked, and a higher internal pressure is created in the main chamber 10 with a given gas generator. Therefore a section of the outer fabric layer 36a serves in this embodiment as a closing element, to block or throttle the gas flow.
The mode of functioning of an airbag according to the present invention, when installed in a motor vehicle, is described with reference to FIGS. 4 to 7, whereby the inside of the vehicle is designated with reference letter F.
FIG. 4 shows the airbag inflating next to a large vehicle occupant G during a side-on collision. If relative movement occurs between the large occupant G and the airbag, the shoulder area of the large occupant G comes into contact with the auxiliary chamber 30 (see FIG. 5). This results in the outer fabric layer 36a (see FIG. 4) covering the valve opening 34, which stems the gas flow from the main chamber 10. This leads to a large internal pressure and therefore to a greater firmness of the main chamber 10, which is sufficient to protect an upper body or thorax area of the large, and generally heavy, occupant G.
FIGS. 6 and 7 show a situation similar to that described above except with a small occupant K. Here too, in the case of a side-on collision a relative movement occurs between the small occupant K and the airbag. However, the shoulder area is located under the auxiliary chamber 30, so that the outer fabric layer 36a is not pressed against the valve opening 34. This results in the gas path from the main chamber 10 to the outflow opening 35 remaining free, resulting in a lower pressure in the main chamber 10.
FIG. 8 shows a second embodiment in a side view. This embodiment includes a main chamber 10 and an auxiliary chamber 30, but no pelvic chamber 20; such a chamber can, however, be present as an option in an airbag implemented in this way. The main chamber 10 and auxiliary chamber 30 are formed by the outer fabric layers 51 and 52 being sewn together around their perimeter and in the transitional area between the main chamber 10 and the auxiliary chamber 30 at a connecting area 57 (see FIG. 9). This results in two connecting openings 14 being formed, respectively located on the left and right of the connecting area 57.
The outflow opening 35 which is located in the first outer fabric layer 51 is covered by a covering fabric 64 whose first and second sides 64a and 64b are not fastened to the first outer fabric layer 51, so that gas coming from the outflow opening 35 can enter the interior of the vehicle. If the auxiliary chamber 30 is pressed onto the inner structure of the motor vehicle, for example by the shoulder of the occupant, the outflow opening 35 is closed by the covering fabric 64 contacting the inner structure, stopping the gas flow. The covering fabric therefore forms the closing element. The basic functional principle is therefore identical with that of the first embodiment.
FIGS. 10 to 12 show a variant of the second embodiment described above. The difference is that two auxiliary chambers 30a and 30b are provided (see FIG. 12). Because of the special arrangement of the two auxiliary chambers 30a and 30b, desirable outflow behaviour can be achieved resulting in an improved means for closing the outflow openings is also implemented.
The cover of the airbag is manufactured of only two fabric sections. FIG. 10 shows a first fabric section 54, from which a first outer fabric layer 51 and a second outer fabric layer 52 are created. Between these layers, the main chamber 10 is created beneath a broken line L, while the auxiliary chambers 30a and 30b are created above the broken line L (see FIG. 12). This variant also includes a connecting area 57. A gas generator opening 59 is provided in the first fabric section 54 in the transitional area between the first outer fabric layer 51 and the second outer fabric layer 52.
FIG. 11 shows a second fabric section 50, from which a first inner fabric layer 55 and a second inner fabric layer 56 are formed. In addition, an outer capture tether 60 is located on the second fabric section 50. The two outflow openings 35 are located in the second fabric section 50 as well as four inner capture tethers 58, which are connected to the first outer fabric layer 51 or the second outer fabric layer 52 during the manufacturing process.
The two fabric sections 50 and 54 are sewn together as described in the following text. The second fabric section 50 is folded over along a mid line M and then the first inner fabric layer 55 is sewn together with the first outer fabric layer 51 along the first seam 53a and the second inner fabric layer 56 is sewn together with the second outer fabric layer 52 along the second seam 53b. Furthermore, the inner capture tethers 58 are joined with the second fabric section 50 and sewn together to respective opposite areas of the outer fabric layers 51 and 52. Finally, all four fabric layers are joined together in connecting area 57 by means of sewing. As a last step, the top edges of the auxiliary chambers 30a and 30b are joined together by means of outer capture tether 60. This results in the configuration shown in FIG. 12, which is a section of the present embodiment similar to the representation of FIG. 9 and which shows the situation when the airbag is fully expanded.
All four fabric layers are sewn together in the connecting area 57. Below this connecting area 57 is the main chamber 10, above the connecting area 57 are the two auxiliary chambers 30a and 30b. The thickness of the two auxiliary chambers is limited by the two capture tethers 58 respectively. The gas flow from the main chamber 10 into the auxiliary chambers 30a and 30b occurs to the left and right of the connecting area 57 (this cannot be seen from the representation in FIG. 12). The two auxiliary chambers 30a and 30b are connected with each other at their upper ends by means of the outer capture tether 60, so that an intermediate area 62, which is basically open to the top and sides, is created between the two auxiliary chambers 30a and 30b. The two outflow openings 35 end in this intermediate area 62, so that direct gas flow onto the vehicle occupant or the side structure of the vehicle is avoided. Outflow openings 35 are closed if the two auxiliary chambers 30a and 30b are pressed onto one another by an external obstacle, for example the shoulder of the occupant. This means the one auxiliary chamber 30a and 30b forms the closing element of the other auxiliary chambers 30a or 30b.
As a person skilled in the art will readily appreciate, the above description is meant as an illustration of implementation of the principles of this invention. This description is not intended to limit the scope or application of this invention in that the invention is susceptible to modification, variation and change, without departing from the spirit of this invention, as defined in the following claims.
Patent Application
20080023945
