DE10106238A1 - Airbag safety system for vehicles has rear seat airbag in gas connection with additional inflatable airbag made of elastic material to force back gas on impact with passenger to refill rear airbag in event of multiple shunt - Google Patents

Abstract

The safety system includes a front seat airbag and a rear seat airbag (7) is gas connection with at least one additional inflatable airbag (8,9) in the front seat area. This additional airbag is made at least in part of elastic material and when the safety system is activated the gas generator blows gas into the rear airbag so that the rear bag inflates behind the seat back (5) of the front seat. When the rear airbag meets the back seat passenger (2) the gas in the rear bag is pressed into the additional air bag which then inflates in the front seat area. The gas in the additional air bag as a result of the elasticity of same is then pressed back in part to refill the rear airbag.

Description

The invention relates to a safety device for a vehicle, in particular for a Motor vehicle, according to the preamble of claim 1.

A generic safety device for a motor vehicle is from DE 94 15 511.9 U1 known, the at least one arranged on a front seat as a vehicle seat Airbag device comprising at least one gas generator and at least one in activated state in the rear area behind a seat back of the vehicle seat inflatable rear airbag and at least one in addition to at least one Rear airbag includes inflatable additional airbag in the area of the front seat, the at least one rear airbag and the at least one additional airbag in the non-activated one Folded basic state are arranged on the vehicle seat.

Specifically, the additional airbag is designed as a side airbag, with a headrest a separate rear airbag as well as on both sides of a seat back of the vehicle seat the headrest each have separate side airbags that are not in each other Connected and filled separately from each other. In the activated, The rear airbag is inflated in front of a vehicle seat behind this located rear passengers inflated and extend the two side airbags each forward on both sides of the head towards a front end area.

DE 93 13 068 U1 describes a structure of a safety device for a motor vehicle known in which a side airbag in the side facing the vehicle door Headrest area is arranged. In the inflated state, the stretches Side airbag in front of the vehicle door next to a head area of the vehicle occupant.

From DE 195 05 216 A1 a structure is also known in which the lateral Headrest areas starting on either side of the head one Vehicle occupants, a side airbag extends forward to the front end area.  

DE 42 18 252.2 also describes a safety device with an airbag in one Motor vehicle known in which an airbag in a headrest of a seat back Vehicle seat is arranged, this airbag as a head airbag in the activated state the head area of a rear passenger sitting behind is inflatable.

All of these safety devices have in common that they are only one Form impact protection for a primary impact. With such a primary impact one The vehicle occupant on the airbag escapes the gas from the airbag, causing this in collapses. It stands for a secondary impact that may follow the primary collision therefore such an airbag is no longer available. In addition, such Airbag assemblies are regularly provided with gas outlets so that a relative high amount of gas must be blown into the airbag for filling. This is on the one hand, expensive and on the other hand requires the use of particularly powerful ones Inflators. In addition, possibly harmful exhaust gases from the Gas generator get into the vehicle interior.

It is already known from DE 199 23 483 A1 in connection with a steering wheel airbag Side chambers on the side of the airbag and / or on the side facing away from the vehicle occupant Form side of the airbag as stretchable elastic fabric parts, in which at one Impact of a vehicle occupant on the airbag gas can be pressed, this gas pressed into the elastic secondary chambers due to the elasticity of the latter Sub-chambers pushed back into the main chamber for refilling after the impact becomes. In the event of a subsequent collision, the main chamber is again used as impact protection to disposal. The secondary chambers are designed so that they are in Unfold the longitudinal direction of the vehicle from the side of the vehicle occupant and thereby for one Sloping impact offer protection.

A similar construction of a safety device for a motor vehicle is also known from FR 27 66 142 known in which also in connection with a steering wheel airbag an elastic Auxiliary chamber is provided, in the event of a driver impact on the steering wheel airbag with elastic expansion of the secondary chamber, gas can be pressed out of the main chamber. Such a structure is also shown in DE 197 24 625 A1. From DE 197 24 625 A1 a similar construction is also shown in connection with a side airbag, which of a B-pillar of a vehicle, starting from the side in a central upper body area is deployable next to the vehicle occupant.  

With these airbags having an elastic secondary chamber, however, there is none Impact protection possible for a rear passenger sitting behind a front seat.

The object of the invention is therefore to provide a safety device for a vehicle, in particular for a motor vehicle to create an effective impact protection for Rear passengers are also given in the event of multiple collisions.

This object is achieved with the features of patent claim 1.

According to claim 1, the at least one rear airbag with the at least one Additional airbag in gas connection, the at least one additional airbag at least is partially made of an elastic material. If the Safety device blows the at least one gas generator gas into the at least one Rear airbag. As a result, only the at least one becomes at the beginning of the airbag activation Inflated rear airbag behind the seat back. In the event of a rear-seat passenger colliding with the At least one rear airbag is at least partially in the gas in this at least one additional airbag can be pressed in, as a result of which this is in the area of the front seat a functional position is inflatable. After a rear-seat occupant has collided the at least one rear airbag is the gas in the at least one additional airbag due to the elasticity of the at least one additional airbag at least partially for one Refillable in the at least one rear airbag.

Such a safety device also provides advantageous occupant protection Multiple collisions possible for a rear passenger sitting behind a front seat, because the at least one rear airbag not only for a primary collision, but also for one Secondary collision and possibly other collisions are available again, because that too Airbag activation does not begin in the gas blown into the at least one rear airbag flows out of the entire airbag system again, but only into the additional airbags is pressed and then by this again for refilling in the at least a rear airbag is pushed back so that it causes a primary collision following secondary collision can in turn form an impact protection. Due to the missing gas outlet openings can also no harmful gases in the Get inside the vehicle.  

This provides the rear occupants with advantageous and effective impact protection Multiple collisions are provided, with the closed airbag system if possible, no gas escapes from the system.

Basically, there are various options for the airbags in the airbag device to arrange folded basic state at the front seat. So is for example a structure conceivable in which the airbag or airbags in the folded basic state in lower area of the vehicle seat, e.g. B. in the area of the seat part and / or Seat base, arranged and recorded. In case of airbag activation then z. B. the rear airbag from this lower area upwards behind the seat back inflated. In a particularly preferred embodiment, the airbags are the Airbag device, however, in the folded basic state in the seat back and / or in a headrest arranged as part of the seat back. This will make it easy Airbag guidance is possible because the rear airbag simply works as a head and / or thorax airbag is inflatable in front of the rear passenger. There is also the Possibility of the individual airbags of the airbag device on different seat parts to arrange. For example, the at least one additional airbag in the Headrest area and the at least one rear airbag in the upper seat back area or be reversed.

The specific arrangement of the individual airbags depends on the specific given installation situation and in particular also of the intended additional airbags Function.

In a first preferred embodiment, the at least one additional airbag can be used as Side airbag in a side area of the backrest and / or in a side area Headrest area may be arranged.

This allows the side airbag to be used in many ways. Such a side airbag can for example as side head and / or thorax and / or pelvic protection on the side next to a vehicle occupant sitting in the front seat will be inflated as soon as the gas is pressed into the side airbag from the rear airbag. Since the side airbag as side head and / or thorax and / or pelvic protection for one in the front seat seated vehicle occupants by those pushed from the rear airbag into the side airbag Gas quantity is only available for a limited period of time, according to one  Particularly preferred further embodiment of the invention can be provided that in in such a case of use of the side airbags, the side airbags in the event of activation the safety device is also inflated at the beginning of the airbag activation be, so that as an advantageous side impact protection even during the Primary collision are available. Because of the elasticity of the side airbags, these are in the event of an impact of a rear passenger on the at least one rear airbag through the In addition, gas pushed into the side airbag continues to inflate, which on the one hand leads to the Advantageously increase the service life of the side airbag and also on the other hand Gas metering for the side airbags can be taken into account advantageously by this z. B. be acted upon by a lower gas dose. The elastic In such a case, areas can preferably, for. B. only from the rear airbag in Push the amount of gas displaced from the additional airbag back into the rear airbag. In a Another preferred use can be such a side airbag on the side next to one vehicle occupants sitting in the front seat also as an intercollision airbag between two serve adjacent seating positions.

Alternatively or additionally, the at least one side airbag can also be used at the same time for lateral support and / or lateral widening in the side area of the at least a rear airbag to be inflated. In the case of a lateral support of the at least a rear airbag ensures that the at least one rear airbag from one In the event of an impact, rear-seat passengers cannot simply be pushed away, which in particular in out-of-position situations, d. H. in situations in which the rear passenger is not in a normal sitting position, may be required. The lateral widening of the Rear airbags can also be particularly advantageous for such out-of-position situations be, as this advantageously absorbs a possible oblique impact of a rear passenger can.

Basically, there is the possibility that one side airbag on each side Seat back area and / or is arranged on a side headrest area. As well can also have several side airbags on a side seat back area and / or on a side headrest area. However, a is particularly preferred Structure in which at least one side airbag on opposite side Seat back areas and / or on opposite side headrest areas is arranged. With such a structure is an advantageous protection on both sides possible for a vehicle occupant sitting in the front seat and / or an advantageous one  lateral support and / or lateral widening in the side area of the at least one Rear airbags possible. This ensures the functional reliability of the invention Overall safety device again significantly increased.

In a particularly preferred embodiment, the at least one rear airbag is in a rear headrest area and / or in a rear seat back area arranged and in front of a rear passenger located behind the front seat as a head and / or inflatable chest and / or pelvic protection. One is special in these areas advantageous integration of the at least one rear airbag in the non-activated basic state possible.

Additionally or alternatively to that described in connection with the side airbags The at least one additional airbag can be used according to one of the additional airbags another preferred embodiment as in front and / or behind a headrest Seat back inflatable headrest airbag to be inflatable. It is particularly preferred here the use of a headrest airbag that is inflatable in front of a headrest this affects the vehicle occupant sitting in the front seat Head spin movements, so-called Whiplash impairments, advantageously avoided or can at least be reduced.

Basically, it is possible that the at least one gas generator is remote from the seat, i. H. away from the location of the airbags, is arranged so that the coupling of the at least a rear airbag with the gas generator via gas lances. According to a preferred Embodiment of the invention, however, is provided for a compact installation situation that the at least one gas generator adjacent to the airbags of the airbag device on Vehicle seat is arranged. This is particularly the case with an arrangement of the Airbag device in the seat back due to the space available there without any problems and possible without problems. When attaching the airbag device in the Headrest area of a seat back, however, the gas generator, for example in the be arranged in the upper seat back area and possibly a gas connection Headrest bars to the airbags in the headrest.

As already mentioned above in connection with the side airbags, which act as a side head and / or Chest and / or pelvic protection on the side next to one sitting in the driver's seat Vehicle occupants are inflatable, has been described, according to one particular  preferred embodiment of the invention, the individual airbags of the airbag device, in particular the additional airbags, also separately by means of the at least one gas generator be filled. The additional airbags can therefore already at the beginning of the activation of the Safety device - if this is necessary - be inflated so that this is possible the gas displaced from the at least one rear airbag into the additional airbags at one Impact of a rear occupant on the at least one rear airbag only additional be inflated what z. B. has an advantageous effect on their service life. This can a safety device with an airbag device are provided, the Airbags in a wide variety of installation situations and thus also possible use situations of airbags can be flexibly adapted in a simple manner. The elastic areas of the In such a case, additional airbags can preferably only be those from the rear airbag in Push the amount of gas displaced from the additional airbag back into the rear airbag.

Furthermore, it can also be provided that when the at least one is refilled Rear airbags by pushing back the gas from the at least one additional airbag additionally gas from the at least one gas generator into the at least one Rear airbag with reduced gas volume compared to the original filling dose is blown. This may be particularly necessary if e.g. B. not the complete gas quantity displaced into the additional airbags back into the at least a rear airbag can be pushed.

The elastic areas of the additional airbags can be covered by an inside Coating of the additional airbag (s) made of an elastic material, preferably a Elastomer. This results in a particularly high level of functional reliability in terms of elasticity. Alternatively, the elastic areas can also be made of a different material than the airbag itself and as separate parts with the Airbag connected.

The gas connection of the at least one rear airbag to the at least one at least Additional airbag made in regions from an elastic material can over at least one tubular connection can be made as an overflow device. in the Area of this tubular connection are in a preferred embodiment, for. B. arranged pressure-dependent valves, which are formed for example by membrane, the are destructible by gas of a predetermined pressure. Such a gas connection is relatively easy to manufacture with high functional reliability.  

Alternatively, the at least one rear airbag and the at least one Additional airbag but also chambers of a multi-chamber airbag, the individual Chambers are connected to one another in a gas-conducting manner by conventional overflow openings. In the area of the overflow openings, conventional valves, for. B. by Membrane which can be destroyed by a predetermined pressure.

So that the gas does not cool down and this leads to problems with regard to the inflation volume can come as well as the elastic areas by the hot gas, for. B. in the case of Using an elastomer layer that will not damage the gas generator advantageously designed as a cold gas generator.

The invention is described in more detail below with reference to a drawing:

Show it:

Fig. 1 is a schematic plan view of a portion of a motor vehicle with a seated behind a front seat and rear seat passengers are arranged in the backrest area airbag device in the non-activated basic state,

FIG. 2a, 1 b are schematic plan views corresponding to FIG. At the start of activation of the safety device, in which a rear air bag is inflated,

Fig. 3a, b are schematic plan views corresponding to FIGS. 1 and 2 in a primary impact of a vehicle occupant on the rear airbag,

Fig. 4 is a schematic plan view corresponding to Figs. 1 to 3, in which after a completed primary impact against a secondary collision, the air displaced from the rear air bag gas is forced back from the auxiliary air bag back into the rear airbag,

Fig. 5 is a schematic plan view of a portion of a motor vehicle having a safety device with an air bag device which is disposed in a front seat of a headrest of a seat back, the non-activated basic state,

Fig. 6 is a schematic plan view corresponding to Fig. 5 with the inflated rear airbag,

Fig. 7 is a schematic plan view corresponding to Fig. 6 after a primary impact on the rear airbag, and

Fig. 8 is a schematic plan view corresponding to Figs. 5 to 7 with wiederbefülltem rear airbag.

In Fig. 1 a plan view is shown on a portion of a motor vehicle 1 schematically, in a rear seat 2, sitting on a rear seat 3 behind a front seat 4.

In a seat back 5 of the front seat, for example in an upper seat back area, an airbag device 6 is arranged here, which has at least one gas generator (not shown here) and a rear airbag 7 as well as a side airbag 8 , 9 arranged on opposite side seat back areas, which in the Fig. 1 shown non-activated basic position 10 of the airbag device 6 are arranged folded in the seat back 5 .

The side airbags 8 , 9 are connected to the rear airbag 7 in a gas-conducting manner via a tubular overflow connection, but this is only shown in broken lines in the illustration in FIG. 1. In the area of this overflow connection 11 , for example, a pressure-dependent membrane can be arranged, which is not shown here, however, which can be destroyed by gas of a predetermined pressure.

The side airbags 8 , 9 are here made at least in regions from an elastic material.

This airbag device 6 is part of a safety device 12 for the motor vehicle 1 .

If the safety device 12 is activated, as can be seen from FIG. 2a, gas is only inflated into the rear airbag 7 by means of the gas generator, which is preferably designed as a cold gas generator, so that only the rear airbag 7 behind at the beginning of the airbag activation the seat back 5 is inflated.

As can also be seen from FIG. 3a, when the rear passenger 2 collides with the rear airbag 7, the gas therein is at least partially pressed into the side airbags 8 , 9 in accordance with the arrows in FIG Front seat 4 are inflatable in their functional position.

Different embodiments of the side airbags are shown in FIG. 3a. The side airbag 9 on the right-hand side of the image is designed such that in the inflated state it supports the rear airbag 7 on the one hand with a first partial region 13 and also widens it on the side, which is, however, only shown extremely schematically here. A second partial area 14 of the side airbag 9 , on the other hand, extends laterally in the inflated state next to a seating position 15 of a vehicle occupant located in the front seat 4 , which is not shown here, however.

On the left half of FIG. 3a, an alternative embodiment is shown in connection with the side airbag 8 , the side airbag 8 here also being designed as a side airbag for the seating position 15 of the front seat 4 in the illustration with solid lines in a first embodiment. As an alternative or in addition to this, the side airbag 8 can also, as shown in dashed lines in FIG. 3a, be designed for the lateral widening and lateral support of the rear airbag 7 .

An alternative embodiment to FIGS . 2a and 3b is shown in FIGS . 2b and 3b. As can be seen from FIG. 2b, the side airbags 8 , 9 are simultaneously inflated at the beginning of the airbag activation, for. B. by means of a separate gas generator. In the event of an impact of the rear passenger on the rear airbag 7 , the side airbags 8 , 9 are then further inflated, as can be seen from FIG. 3b, by at least a part of the gas blown into the rear airbag 7 from this into the side airbags 8 , 9 is pushed in. In the case of the side airbag 9 located on the right half of the figure , the side airbag 9 is designed such that it is now inflated into the position shown in FIG. 3b by additional expansion of its elastic regions. That is, the side airbag 9 also increases in volume. Alternatively, as shown in dashed lines on the left side of FIG. 3b, the side airbag 8 can also be enlarged by an additional volume. Possibly. For this purpose, the side airbags 8 , 9 are divided into different chambers, but this is no longer shown here.

As is shown schematically for all of the embodiments in FIG. 4, after the rear seat occupant 2 has collided, after the latter has been moved back again approximately to a normal sitting position, the gas in the side airbags 8 , 9 can be due to the elasticity of at least partial areas of the side airbags 8 , 9 are at least partially pushed back into the rear airbag 7 for refilling so that it is available again for a secondary impact as an impact protection device for the rear occupant 2 . FIG. 4 shows this retraction extremely schematically and by way of example for all of the embodiments previously explained in connection with FIGS . 2a, 2b, 3a and 3b.

FIG. 5 shows an alternative embodiment of a safety device 18 , in which an airbag device 19 is arranged in a headrest 20 of the seat back 5 of the front seat 4 , as can be seen in FIG. 5, which shows an airbag device 19 in the folded basic state is. This airbag device 19 comprises a rear airbag 21 , a headrest airbag 22 and in each case a side airbag 23 , 24 arranged on opposite lateral headrest regions.

The individual airbags 21 , 22 , 23 , 24 are each connected in a gas-conducting manner by means of overflow connections 25 , 26 , 27 .

The headrest airbag 22 and the side airbags 23 , 24 are also each made in regions from an elastic material.

If the safety device 18 is activated, gas is first blown into the rear airbag 21 via a gas generator, not shown here, so that only the rear airbag 21 is inflated behind the seat back 5 at the beginning of the airbag activation, as can be seen from FIG. 6.

In the event of an impact of a rear passenger, not shown here, according to the arrow 28 in FIG. 7 on the rear airbag 21 , the gas therein is at least partially pressed into the headrest airbag 22 and the side airbags 23 , 24 according to the arrows, which is also shown in FIG . 7 is shown schematically. The left side airbag 23 in the image plane of FIG. 7 serves in an advantageous double function in addition to the lateral widening and the lateral support of the rear airbag 21 .

The alternative embodiment of the side airbag 24 shown on the right-hand image plane of FIG. 7 can be inflated with a partial area in the direction of the rear airbag 21 in order to widen it laterally and to support it laterally. In contrast, a second partial area of this side airbag 24 can be inflated in the area laterally next to a head position of a seat user of the front seat 4 .

The headrest airbag 22 , on the other hand, is inflated in front of the headrest and can thereby avoid or at least reduce the risk of impairments to the seat user of the front seat 4 with respect to head-throwing movements, that is to say so-called whiplash impairments.

After a primary impact has occurred, the elasticity of the airbags 22 , 23 , 24 forming the additional airbags can then at least partially blow the gas contained therein back into the rear airbag 21 for refilling, as is shown schematically in FIG. 8 by the solid arrows is shown.

In addition, as shown in FIG. 8 with the dashed arrows, gas can also be blown from the gas generator into the rear airbag 21 , but with a reduced gas quantity dose.

The rear airbag 21 is thus advantageously available again for a secondary collision in the inflated state.

LIST OF REFERENCE NUMBERS

1

motor vehicle

2

the rear seat passengers

3

Rear seat

4

front seat

5

seatback

6

airbag device

7

fond airbag

8th

side airbags

9

side airbags

10

initial position

11

overflow connection

12

safety device

13

First section

14

Second section

15

seating position

16

First part

17

Second part

18

safety device

19

airbag device

20

headrest

21

fond airbag

22

Headrests Airbag

23

side airbags

24

side airbags

25

overflow connection

26

overflow connection

27

overflow connection

28

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Claims (16)

1. Safety device for a vehicle, in particular for a motor vehicle, with at least one airbag device arranged on a front seat as a vehicle seat, the at least one gas generator and at least one rear airbag inflatable in the activated state in the rear area behind a seat back of the vehicle seat and at least one in addition to the at least one Rear airbag in the area of the front seat comprises an inflatable additional airbag, the at least one rear airbag and the at least one additional airbag being arranged folded in the non-activated basic state on the vehicle seat, characterized in that the at least one rear airbag ( 7 ; 21 ) with the at least one additional airbag ( 8 , 9 ; 22 , 23 , 24 ) is in gas connection that the at least one additional airbag ( 8 , 9 ; 22 , 23 , 24 ) is at least partially made of an elastic material, and that if the safety device ( 12 ; 18 ) is activated de r at least one gas generator gas in the at least one rear airbag ( 7 ; 21 ) blows in such a way that at the beginning of the airbag activation, the at least one rear airbag ( 7 ; 21 ) behind the seat back ( 5 ) can be inflated, so that if a rear passenger ( 2 ) collides with the at least one rear airbag ( 7 ; 21 ), this Any gas present can be pressed at least partially into the at least one additional airbag ( 8 , 9 ; 22 , 23 , 24 ), so that it can be inflated in a functional position in the area of the front seat ( 4 ), and that after a rear passenger ( 2 ) has collided on the at least one rear airbag ( 7 ; 21 ) the gas in the at least one additional airbag ( 8 , 9 ; 22 , 23 , 24 ) due to the elasticity of the at least one additional airbag ( 8 , 9 ; 22 , 23 , 24 ) at least partially for one Refillable into the at least one rear airbag ( 7 ; 21 ), 2. Safety device according to claim 1, characterized in that the airbags ( 7 , 8 , 9 ; 21 , 22 , 23 , 24 ) of the airbag device ( 6 ; 19 ) in the folded basic state in the seat back ( 5 ) and / or in a headrest ( 20 ) of the seat back ( 5 ) are arranged. 3. Safety device according to claim 2, characterized in that the at least one additional airbag ( 8 , 9 ; 23 , 24 ) is arranged as a side airbag in a side seat back area and / or in a side headrest area. 4. Safety device according to claim 3, characterized in that the at least one side airbag ( 8 , 9 ; 23 , 24 ) as lateral head and / or thorax and / or pelvic protection laterally next to a vehicle occupant sitting on the front seat ( 4 ) and / or for lateral support and / or lateral widening in the side area of the at least one rear airbag ( 7 ; 21 ) is inflatable. 5. Safety device according to claim 3 or 4, characterized in that in each case at least one side airbag ( 8 , 9 ; 23 , 24 ) is arranged on opposite side seat back areas and / or on opposite side headrest areas. 6. Safety device according to one of claims 2 to 5, characterized in that the at least one rear airbag ( 7 ; 21 ) is arranged in a rear headrest area and / or in a rear seat back area and in front of a rear passenger located behind the front seat ( 4 ) as Head and / or thorax and / or pelvic protection is inflatable. 7. Safety device according to one of claims 1 to 6, characterized in that the at least one additional airbag as front and / or behind a headrest ( 20 ) of the seat back ( 5 ) inflatable headrest airbag ( 22 ) is inflatable. 8. Safety device according to one of claims 1 to 7, characterized in that the at least one gas generator is arranged adjacent to the airbags ( 7 , 8 , 9 ; 21 , 22 , 23 , 24 ) of the airbag device on the vehicle seat. 9. Safety device according to one of claims 1 to 8, characterized in that the additional airbags ( 8 , 9 ; 22 , 23 , 24 ) of the airbag device ( 6 ; 19 ) can also be filled separately by means of the at least one gas generator. 10. Safety device according to one of claims 1 to 9, characterized in that when refilling the at least one rear airbag ( 7 ; 21 ) by pushing back the gas from the at least one additional airbag ( 8 , 9 ; 22 , 23 , 24 ) additional gas the at least one gas generator can be blown into the at least one rear airbag ( 7 ; 21 ) with a reduced amount of gas compared to the original filling dose. 11. Safety device according to one of claims 1 to 10, characterized in that the elastic regions are formed by an inside coating of the airbag (s) ( 8 , 9 ; 22 , 23 , 24 ) made of an elastic material, preferably an elastomer, or that the elastic regions are formed from a different material than the airbag and are connected to the airbag as separate parts. 12. Safety device according to one of claims 1 to 11, characterized in that the gas connection of the at least one rear airbag ( 7 ; 21 ) to the at least one at least partially made of an elastic material additional airbag ( 8 , 9 ; 22 , 23 , 24 ) via at least one tubular connection is made as an overflow device ( 11 ; 25 , 26 , 27 ). 13. Safety device according to claim 12, characterized in that in Area of the tubular connection pressure-dependent valves are arranged.   14. Safety device according to claim 12 or 13, characterized in that the valves are diaphragms that can be destroyed by gas of a predetermined pressure. 15. Safety device according to one of claims 1 to 11, characterized in
that the at least one rear airbag and the at least one additional airbag are chambers of a multi-chamber airbag, and
that the individual chambers are connected to one another in a gas-conducting manner by conventional overflow openings. 16. Safety device according to one of claims 1 to 15, characterized characterized in that the gas generator is a cold gas generator.