Abstract:
The invention relates a gas bag ( 5 ) which is used for a car passenger-protecting system and comprises a gas generator ( 20 ) in which at least a part of the envelop of the bag sac is incorporated in the remaining segment of the envelop of the gas bag. The aim of said invention is to obtain a target positioning of said gas bag prior to blowing it. For this purpose, the segment of the envelop ( 10 ) forms a narrow filling channel ( 15 ) which extends in a predefined discharge direction ( 70 ) and can be connected to the gas generator.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a gas bag for a car passenger-protecting system. 
     A gas bag of this type is disclosed by the British laid-open specification 2 318 767. in this previously known gas bag, an upper part of the gas bag envelope is turned back into a lower part of the gas bag envelope. As a result of turning back the gas bag parts into one another in the previously known gas bag, the gas bag unfolds in a predefined manner or in a predefined sequence with respect to the individual gas bag envelope sections. In practical terms, when the previously known gas bag is inflated, first of all the lower part of the gas bag envelope is inflated. Only when the lower part of the gas bag envelope has unfolded is the upper, folded-back part of the gas bag envelope forced out of the lower part of the gas bag envelope on account of the gas pressure, which means that time-delayed inflation of the upper part of the gas bag envelope is achieved. 
     SUMMARY OF THE INVENTION 
     The invention is based on the object of specifying a gas bag for a car passenger-protecting system in which specific positioning of the gas bag or a part thereof is achieved before inflation. 
     According to the invention, a narrow filling channel is understood to mean a filling channel which is longer in the deployment direction than it is wide in cross section. 
     A substantial advantage of the gas bag according to the invention is to be seen in the fact that it has a preferential direction when inflated. In practical terms, the part of the gas bag envelope that is turned back into the filling channel is, so to speak, shot out of the filling channel during inflation. According to the invention, this is achieved by means of the narrow filling channel, which predefines a preferential direction or a shooting-out direction. This is because, when the gas generator is triggered, a relatively high pressure is built up in the filling channel in a relatively short time. The envelope material that is turned back is expelled from the filling channel on account of this high pressure and unfolds in the predefined deployment direction, which corresponds to the longitudinal direction of the narrow filling channel, because of the directed ejection impulse. In other words, by providing the narrow filling channel, specific positioning of the gas bag or a part thereof is achieved, in that the gas bag or a part of the gas bag is shot out of the filling channel specifically in a predefined direction. 
     In order to achieve the situation where the gas pressure generated by the gas generator is preferably used to eject the turned-back part of the gas bag envelope, it is seen as advantageous if the filling channel is or can be connected directly to the gas generator. 
     According to an advantageous refinement of the gas bag according to the invention, provision is made for the gas bag to be connected to one end of the filling channel and for the turned-back part of the gas bag envelope to be located immediately in front of the connection point of the gas generator. In this advantageous refinement of the gas bag according to the invention, the turned-back part of the gas bag envelope is therefore located immediately in front of a gas exit opening from the gas generator, which means that a particularly high ejection impulse is exerted on the turned-back gas bag envelope, which leads to particularly rapid unfolding of the gas bag envelope in the predefined deployment direction. 
     According to another advantageous refinement of the gas bag according to the invention, provision is made for the filling channel to form a lateral pocket, which extends laterally beside the connection point of the gas generator. The connection point of the gas generator is therefore located in the front part of the filling channel. 
     Part of the gas bag envelope can be inserted into the filling channel particularly simply by the gas bag envelope being stuffed into the filling channel unfolded. 
     In order to achieve unfolding of the gas bag envelope in a predefined manner, it is seen as advantageous if the turned-back part of the gas bag envelope is, at least to some extent, zigzag folded, pleated and/or rolled together. 
     In this case, unfolding of the gas bag envelope along the predefined deployment direction may then advantageously be achieved if the turned-back region of the gas bag envelope is zigzag-folded, pleated and/or rolled together at the end of the envelope facing away from the filling channel, the zigzag-folded, pleated and/or rolled together envelope pack is folded together at least once, forming an envelope pack with a U-shaped cross section, and the U-shaped envelope pack is pushed into the filling channel. 
     Otherwise, it is seen as advantageous if the gas bag has two or more gas bag chambers. In this case, at least one of the gas bag chambers can be an inner gas bag chamber, which is surrounded by an outer gas bag chamber of the gas bag. 
     In the gas bag according to the invention, the filling channel can be formed in different ways. It is seen as advantageous if the filling channel is formed laterally, at least partly, by means of a seam in the gas bag envelope. 
     Instead, if the gas bag has a plurality of gas bag chambers, the filling channel can be formed, at least partly, by side walls of an inner gas bag chamber. 
     Furthermore, the filling channel can advantageously be formed by a diffuser layer fitted in the gas bag and/or by retaining straps. 
     In order to ensure that the part of the gas bag envelope turned back into the filling channel unfolds along the predefined deployment direction, it is seen as advantageous if the filling channel is at least partly tubular. At least at its open channel end, the cross section of the filling channel can then widen like a funnel, in order to simplify turning back or pushing in the envelope pack when folding the gas bag together. 
     Furthermore, it is seen as advantageous if the gas bag according to the invention is what is known as a pelvis-thorax air bag or gas bag. Such a pelvis-thorax gas bag is advantageously fitted in a backrest of a motor vehicle seat, the predefined deployment direction of the filling channel extending parallel to the backrest of the motor vehicle seat, in the direction of the vehicle seat area. 
     Otherwise, it is seen as advantageous if the gas bag according to the invention is what is known as a head-thorax gas bag. In order then to achieve the situation where the head region of the head-thorax gas bag moves into the predefined position particularly quickly, it is seen as advantageous if the gas bag is fitted in a backrest of a motor vehicle seat in such a way that the predefined deployment direction of the filling channel extends parallel to the backrest, in the direction of the vehicle roof. 
     The gas bag can advantageously also be a head-thorax-pelvis gas bag. In this case, the head region and/or the pelvis region of the gas bag can in each case be turned back into a filling channel. There can also be two filling channels. 
     In addition, in the case of a head-thorax-pelvis gas bag, it is seen as advantageous if the gas bag is fitted in a backrest of a motor vehicle seat in such a way that the predefined deployment direction of the filling channel for the head region extends parallel to the backrest of the motor vehicle seat, in the direction of the vehicle roof, and/or the predefined deployment direction of the filling channel for the pelvis region extends parallel to the backrest of the motor vehicle seat, in the direction of the vehicle seat area. Both the pelvis region and the head region in each case advantageously have an appropriately oriented filling channel or shot channel. 
     The invention also relates to a method for folding a gas bag. 
     In order to achieve specific positioning of the gas bag or parts of the gas bag before inflation in such a method, the invention provides for the gas bag to be folded in such a way that part of the gas bag envelope is inserted into a narrow filling channel, formed by part of the gas bag envelope, which extends along a predefined deployment direction. 
     The turned-back or inserted part of the gas bag envelope can in this case be stuffed into the filling channel unfolded. 
     In order to ensure defined unfolding of the gas bag, however, it is seen as advantageous if the part of the gas bag envelope that is turned back is, at least partly, zigzag folded, pleated and/or rolled together. 
     Particularly rapid unfolding of the gas bag envelope is then advantageously achieved if the turned-back region at the end of the envelope facing away from the filling channel is firstly zigzag folded, pleated and/or rolled together, the zigzag folded, pleated and/or rolled together envelope pack is then firstly folded together once, forming an envelope pack with a U-shaped cross section and the U-shaped envelope pack is then pushed into the filling channel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1   a  shows a sectional view of a gas bag according to a first exemplary embodiment of the present invention. 
         FIG. 1   b  shows a sectional view of a gas bag according to a first exemplary embodiment of the present invention. 
         FIG. 1   c  shows a sectional view of a gas bag according to a first exemplary embodiment of the present invention. 
         FIG. 1   d  shows a sectional view of a gas bag according to a first exemplary embodiment of the present invention. 
         FIG. 2   a  shows a sectional view of a gas bag according to a first exemplary embodiment of the present invention. 
         FIG. 2   b  shows a sectional view of a gas bag according to a first exemplary embodiment of the present invention. 
         FIG. 2   c  shows a sectional view of a gas bag according to a first exemplary embodiment of the present invention. 
         FIG. 2   d  shows a sectional view of a gas bag according to a first exemplary embodiment of the present invention. 
         FIG. 3   a  shows a sectional view of a gas bag according to a second exemplary embodiment of the present invention. 
         FIG. 3   b  shows a sectional view of a gas bag according to a second exemplary embodiment of the present invention. 
         FIG. 3   c  shows a sectional view of a gas bag according to a second exemplary embodiment of the present invention. 
         FIG. 3   d  shows a sectional view of a gas bag according to a second exemplary embodiment of the present invention. 
         FIG. 4   a  shows a sectional view of a gas bag according to a second exemplary embodiment of the present invention. 
         FIG. 4   b  shows a sectional view of a gas bag according to a second exemplary embodiment of the present invention. 
         FIG. 4   c  shows a sectional view of a gas bag according to a second exemplary embodiment of the present invention. 
         FIG. 4   d  shows a sectional view of a gas bag according to a second exemplary embodiment of the present invention. 
         FIG. 5   a  shows a sectional view of a gas bag according to a third exemplary embodiment of the present invention. 
         FIG. 5   b  shows a sectional view of a gas bag according to a third exemplary embodiment of the present invention. 
         FIG. 6   a  shows a sectional view of a gas bag according to a fourth exemplary embodiment of the present invention. 
         FIG. 6   b  shows a sectional view of a gas bag according to a fourth exemplary embodiment of the present invention. 
         FIG. 7   a  shows a sectional view of a gas bag according to a fifth exemplary embodiment of the present invention. 
         FIG. 7   b  shows a sectional view of a gas bag according to a fifth exemplary embodiment of the present invention. 
         FIG. 8   a  shows a sectional view of a gas bag according to a sixth exemplary embodiment of the present invention. 
         FIG. 8   b  shows a sectional view of a gas bag according to a sixth exemplary embodiment of the present invention. 
         FIG. 9   a  shows a sectional view of a gas bag according to a seventh exemplary embodiment of the present invention. 
         FIG. 9   b  shows a sectional view of a gas bag according to a seventh exemplary embodiment of the present invention. 
         FIG. 10   a  shows a sectional view of a gas bag according to a eighth exemplary embodiment of the present invention. 
         FIG. 10   b  shows a sectional view of a gas bag according to a eighth exemplary embodiment of the present invention. 
         FIG. 11   a  shows a sectional view of a gas bag according to a ninth exemplary embodiment of the present invention. 
         FIG. 11   b  shows a sectional view of a gas bag according to a ninth exemplary embodiment of the present invention. 
         FIG. 11   c  shows a sectional view of a gas bag according to a ninth exemplary embodiment of the present invention. 
         FIG. 11   d  shows a sectional view of a gas bag according to a ninth exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the figures, the same designations are used for identical or comparable components. 
       FIGS. 1   a  to  1   d  show a first exemplary embodiment of a gas bag  5  according to the invention. It is possible to see an envelope section  10  which forms a filling channel  15 . The length L of the filling channel is in this case greater than the width b or the diameter b of the filling channel  15 . Connected to the filling channel  15  is a gas generator  20 , which can feed gas into the gas bag  5  at a gas outlet opening  25  or a starting point of the gas generator. 
     In  FIGS. 1   b  to  1   d  it is shown in detail how the gas bag envelope  30  of the gas bag  5  is folded together. First of all, the end  35  of the envelope facing the filling channel  15  is, for example, zigzag folded, rolled or pleated. In the following text, zigzag folding will be assumed by way of example. In this case, a zigzag-folded envelope pack  40  is produced, as can be seen well in  FIG. 1   b . The zigzag-folded envelope  40  is then folded together or laid together in the middle, which produces a U-shaped envelope pack  45 . The U-shaped envelope pack  45  can be seen well in  FIG. 1   c.    
     The U-shaped envelope pack  45  is then inserted or pushed or stuffed into the envelope section  10  and thus into the filling channel  15 . 
     As can be seen in  FIGS. 1   a  to  1   d , the filling channel  15  is located laterally beside the gas generator and forms a type of side pocket  47 . The gas outlet opening  25  of the gas generator  20  is in this case located in the front region  50  of the filling channel  15 , that is to say at the end facing away from the closed end  55  of the filling channel  15 . 
       FIGS. 2   a  to  2   d  show how the gas bag according to  FIGS. 1   a  to  1   d  unfolds. Following an activation of the gas generator  20 , a high positive pressure forms in the region  60 , which leads to the U-shaped envelope pack  45  shooting out. In practical terms, the U-shaped envelope pack  45  is drawn out of the filling channel  15  in the region  65  of the gas bag envelope. 
     On account of the filling channel  15  and the orientation of the filling channel  15 , a predefined deployment direction  70  is predefined.  FIGS. 2   b  to  2   c  reveal folds  75  on account of an accumulation of material. These folds  75  are unfolded only when the envelope pack  45  has been shot dynamically out of the filling channel  15  and the dynamics of the mass components have equalized, so that the gas bag  10  reaches its final shape on account of the tailoring of the material. 
     A second exemplary embodiment of a gas bag according to the invention, which is, for example, a head-thorax gas bag, is illustrated in  FIGS. 3   a  to  3   d  and  4   a  to  4   d . The gas bag  100  has two gas bag chambers  105  and  110 , which are separated from each other by a separating point, for example a separating seam  115 . By means of the separating seam  115 , a filling channel  120 , in which the envelope material of the lower gas bag chamber  110  is pushed as a U-shaped envelope pack  125 , is formed in the lower gas bag chamber  110 . 
     In the gas bag  100 , the lower gas bag chamber  105  forms the pelvis chamber and the upper gas bag chamber  110  forms the thorax chamber. 
     With regard to the folding of the lower gas bag chamber  110  and with regard to the unfolding operation in the lower gas bag chamber  110 , reference should be made to the explanations in connection with  FIGS. 1   a  to  1   d  and  2   a  to  2   d , since the lower gas bag chamber  110  is folded substantially in the same way as the gas bag  5  according to  FIGS. 1   a  to  1   d  and  2   a  to  2   d , so that it unfolds in a comparable manner to the gas bag  5 . 
     The upper gas bag chamber  105  can be inflated directly by the gas generator  20 ; this presupposes that there is an appropriate connection between the upper gas bag chamber  105  and the gas generator  20 . Instead, the upper gas bag chamber  105  can also be inflated indirectly via the lower gas bag chamber  110 ; this then presupposes appropriate transfer openings between the two gas bag chambers  105  and  110 . 
     A third exemplary embodiment of a gas bag according to the invention is shown in  FIGS. 5   a  and  5   b . This gas bag  200  can be, for example, a head-thorax gas bag. 
     In the gas bag  200 , a filling channel  205  is formed by a diffuser layer  210 . Instead of the diffuser layer  210  or in addition to this, restraining straps can also be used to form the filling channel  205 . 
     In  FIGS. 5   a  and  5   b , arrows  215  indicate how gas emerges from the gas generator  20  at the gas outlet opening  25  and penetrates into the filling channel  205 . 
       FIG. 5   b  shows the gas bag  200  according to  FIG. 5   a  in section along the section plane AA′. 
     The part of the gas bag envelope adjacent to the filling channel in the gas bag  200  forms the head region of the air bag; the remaining envelope region the thorax region. 
     A fourth exemplary embodiment of a gas bag according to the invention is shown in  FIGS. 6   a  and  6   b . The gas bag  300 , which can be a pelvis-thorax gas bag, has two gas bag chambers  305  and  310 . In this case, the lower gas bag chamber  305  forms the pelvis region of the gas bag, the upper gas bag chamber  310  the thorax region. 
     The gas generator  20  fills the lower gas bag chamber  305  at its gas outlet opening  305  and the upper gas bag chamber  310  at a further gas outlet opening  315 . 
     The lower gas bag chamber  305  becomes narrower toward the region of the gas outlet opening  25  and thus forms a filling channel  320 , into which both the envelope material of the lower chamber  305  and the envelope material of the upper chamber  310  can be turned as the gas bag is folded together. 
       FIG. 6   b  shows the gas bag  300  in a section along the section line AA′. 
       FIGS. 7   a  and  7   b  show a fifth exemplary embodiment of a gas bag according to the invention.  FIG. 7   a  shows the gas bag  350  in the inflated state and  FIG. 7   b  shows the gas bag in the partly folded-together state. 
     The gas bag  350  has two gas bag chambers  355  and  360 , which are separated from each other by a seam  365 . The gas generator  20  with its two gas outlet openings  25  and  315  inflates the two gas bag chambers  355  and  360  separately. 
     By means of the seam  365 , a filling channel  375  is formed in the lower gas bag chamber  360 , into which the envelope material of the lower gas bag chamber  360  is pushed or turned as a zigzag-folded envelope pack  380 . In this case, the envelope pack  380  is arranged immediately in front of the gas outlet opening  25 , so that the gas stream from the gas generator  20  so to speak shoots or catapults the envelope pack  380  out of the filling channel  375  along the deployment direction  385 . 
     A sixth exemplary embodiment of a gas bag according to the invention is illustrated in  FIGS. 8   a  and  8   b . The gas bag  400  has an upper gas bag chamber  405  and a lower gas bag chamber  410 . The two gas chambers  405  and  410  are separated from each other, for example by means of a seam  415  or another type of separating point (for example an adhesive bonding point). 
     The envelope of the lower gas bag chamber  410  is arranged as a zigzag-folded envelope pack  420  partly immediately in front of the gas outlet opening  25  of the gas generator  20  and partly in a side pocket  425  of a filling channel  430 . 
       FIGS. 9   a  and  9   b  show a seventh exemplary embodiment of a gas bag according to the invention. The gas bag  450  again has an upper gas bag chamber  455  and a lower gas bag chamber  460 , which are separated from each other by a separator  465 , for example a separating seam. The envelope of the lower gas bag chamber  460  is zigzag-folded as it is folded together and is accommodated as a zigzag-folded envelope pack  420  partly in a side pocket  425  and partly in a filling channel  430 . 
     In summary, the seventh exemplary embodiment according to  FIGS. 9   a  and  9   b  differs from the sixth exemplary embodiment according to  FIGS. 8   a  and  8   b  in that the region of the side pocket  425  is separated from the remaining filling channel  430  by the separating seam  465 . 
       FIGS. 10   a  and  10   b  illustrate an eighth exemplary embodiment of a gas bag according to the invention. The gas bag  500  is what is known as a head-thorax gas bag, which has a head chamber  505  as the upper chamber  505  and a lower chamber  510  as a thorax chamber. The two chambers  505  and  510  are separated by a separating point  515 , for example a seam. In the upper chamber  505 , a filling channel  520  is formed by the seam  515 . 
     When the gas bag  500  according to  FIGS. 10   a  and  10   b  is folded together, the upper chamber  505  is folded together to form an envelope pack  525 , which is inserted into the filling channel  520 . 
     If the gas generator  20  is activated, then gas emerges from the gas outlet opening  25  and catapults the envelope pack  525  out of the filling channel  520 , so that the predefined deployment direction is achieved by means of the filling channel  520 . 
       FIGS. 11   a  to  11   d  show a ninth exemplary embodiment of a gas bag  600  according to the invention. The gas bag comprises an upper chamber  605  and a lower chamber  610 . The envelope pack  630  is stuffed into the filling channel  620  “unfolded”. The arrows  640 ,  650  and  660  show the unfolding of the gas bag  600  upon activation of the gas generator  20 . 
     Given the disclosure of the present invention, one versed in the art would appreciate that there may be other embodiments and modifications within the scope and spirit of the invention. Accordingly, all modifications attainable by one versed in the art from the present disclosure within the scope and spirit of the present invention are to be included as further embodiments of the present invention. The scope of the present invention is to be defined as set forth in the following claims.