WO2006089720A1

WO2006089720A1 - Air bag restraint system

Info

Publication number: WO2006089720A1
Application number: PCT/EP2006/001576
Authority: WO
Inventors: Walter Eberle; Christian Götz; Stefan Hamels; Simon Kramer; Julien Richert
Original assignee: Daimlerchrysler Ag
Priority date: 2005-02-25
Filing date: 2006-02-22
Publication date: 2006-08-31
Also published as: DE102005008653A1; DE102005008653B4

Abstract

Air bag restraint system (1) has an air bag (3), a gas generator (2) and an air bag restricting device, which limits the maximum deployment distance of air bag according to parameters relating to passenger load. Air bag restricting device has a storage device for rebound strap limiting the deployment distance of air bag whereby the storage device is arranged outside the air bag.

Description

Airbag restraint system

The invention relates to an airbag restraint system according to the preamble of patent claim 1.

In modern vehicle construction increasingly restraint systems are used, which are adapted in the event of an accident or an accident on the in-vehicle occupants. For this purpose, occupant-relevant parameters are first recorded and subsequently evaluated or passed on to the restraint systems. In this way it is ensured that the restraint systems are optimally adjusted according to the respective situation, whereby the protection of vehicle occupants is increased.

From DE 298 05 217 Ul, for example, a device is known with which the shape of a gas bag and in particular the unfolding distance in the unfolded state can be influenced. For this purpose, arranged in the airbag tethers are provided whose length is varied by a sensor-controlled AufwiekelVorrichtung. In the case of restraint, the position of the vehicle occupant is detected by a sensor and the length of the tethers is limited accordingly. To limit the length of the tethers arranged in the airbag take-up devices are provided. From DE 100 20 795 Al it is known, depending on the position of the gas bag restraint system associated vehicle seat, to change the length of the located in the gas bag portion of a tether.

Against the background of this prior art, the invention has for its object to provide an airbag restraint system in which the deployment path of the airbag is limited, which allows reliable deployment to the predetermined deployment position of the airbag.

This object is achieved by an airbag restraint system having the features of patent claim 1.

Accordingly, the gas bag restraint system according to the invention with an airbag and a gas generator is distinguished by an airbag limiting device which limits the maximum deployment path of the airbag as a function of occupant-relevant parameters. The airbag-limiting device has a storage device for at least one limiting band of the airbag limiting tether, wherein the storage device is arranged outside of the airbag. If in the context of the invention of deployment path is mentioned, so is the distance from the vehicle elements in which the airbag is arranged to the ideal impact point of an occupant on the unfolded airbag meant. The occupancy parameters are all parameters which have an influence on the occupant's load in the event of an accident. Examples include the weight of the occupant, the speed of the vehicle before or during the impact, the size of the occupant and the position of the occupant on his vehicle seat. According to the invention, a tether is provided whose length has a direct influence on the deployment path of the gas bag. In order to ensure a safe deployment of the gas bag regardless of the length of the tether, a storage device for the tether is provided. The storage device is designed so that it reliably provides a certain length of tether at all times. The storage device is arranged outside the gas bag. This means that the storage device is not arranged in the gas bag but in the vicinity of the gas bag. The arrangement of the storage device, which is independent of the gas bag, ensures that the gas bag can reliably deploy independently of the storage device of the tether at each set length of the tether. Thus, the invention can also be used independently of any gas bag form or airbag deployment.

Advantageous embodiments can be found in the dependent claims.

An easy way to ensure control of the deployment path of the airbag in dependence on occupant relevant parameters is to set the maximum deployment path of the airbag in dependence on the position of the restraint system associated vehicle seat. In such a control, it is believed that a small, light person places the vehicle seat further forward relative to the steering wheel, and a large, heavy person places the vehicle seat further to the rear. Thus, only the position of the vehicle seat provides information that represents occupant load relevant parameters. This design is particularly advantageous because of the position the vehicle seat particularly easy to capture and transferred to the airbag-limiting device. It is also conceivable to determine the maximum deployment path of the gas bag by a linear, a non-linear or a limited linear function of the position of the restraint system associated vehicle seat.

For example, a limitation of the airbag size adjustment may result from a seating position that is larger or smaller than a seating position for driving or comfortable sitting. This is for example given in two-door vehicles when the seat is adjusted for easy boarding. Another limitation may result from technical feasibility, for example, space reasons. This limitation is then mainly in the edge region of the seat adjustment and the setting of

Limiting device provided. It is also conceivable to provide a limitation in the middle. This then has the effect that when the seat is arranged in the region of middle seating positions, no variation on the gas bag restraint system is made.

It is conceivable to mechanically connect the position of the vehicle seat with the airbag limiting device. A mechanical coupling between the vehicle seat and gas bag boundary means represents a particularly reliable and störunanfällige coupling. In this way, it is always ensured that the gas bag limiting device adjusts the maximum deployment path of the gas bag in dependence on the position of the vehicle seat and an optimal adaptation of the Gas bag restraint system is ensured. Of course, it is also conceivable to carry out the coupling between the position of the vehicle seat and the airbag-limiting device electrically. To Sensors are required to detect the position of the vehicle seat. Furthermore, an evaluation unit and an actuator connected to the evaluation unit is necessary, which sets the maximum deployment path of the gas bag via the gas bag boundary device. The actuator may be, for example, an electric drive. It is just as conceivable to use other widely used drives, such as hydraulic drives.

As a mechanical coupling, a Bowden cable can be provided. When a Bowden cable is a structurally simple component, which also still works reliably after many load changes. A Bowden cable is a proven in the automotive sector, often used and therefore cost-effective component.

As storage device for the tether, a winding shaft may be provided. It is conceivable to connect the one end of the tethers with the airbag and to connect the other end of the tethers with the winding shaft and roll up on this. The tethers can be arranged both inside and outside the airbag. Of course, both arrangements are conceivable. The position of the winding shaft thereby directly influences the length of the tether available in the case of an unfolding gas bag. It is conceivable to unwind the tether when changing the position of the winding shaft. It is also conceivable to produce only a tether on the winding shaft, to block the winding shaft and to provide the lots when deploying the airbag available. A particularly space-saving solution is given when the winding shaft is arranged in a housing of the gas generator. It is conceivable, for example, to store the winding shaft rotatably mounted on the gas generator. This solution is particularly space-saving, since no additional space is required for the gas bag boundary device. In addition, the straps stored on the winding shaft are available in the immediate vicinity of the gas bag and can be removed directly from the storage device when the gas bag is deployed. The tether is where it is needed, so that always a safe deployment is guaranteed.

The winding shaft may be connected directly or indirectly with the Bowden cable. The winding shaft can serve as a storage device for at least a portion of the Bowden cable. Between the foremost position of a vehicle seat and the rearmost position of a vehicle seat can be up to 30 cm difference. These 30 cm are therefore also available with the Bowden cable as a control variable. Due to the limited space requirement within the gas bag module or in the vicinity of an airbag module brings the possibility to wind the Bowden cable on the winding shaft, a considerable space advantage. Depending on how much Bowden cable is wound on the winding shaft, the winding shaft takes a changed angular position relative to the fixed gas generator. The winding shaft is then fixed over the Bowden cable. This means that each seating position is assigned a specific angular position of the winding shaft. About the changed angular position, the Fangbandlose can be adjusted, ie the length of the fan belt, which is available in the event of deployment of the gas bag. Here, the relationship between Bowden cable and tether be coupled via the winding shaft such that the more Bowden cable is wound on the winding shaft -Sitz takes a front position the less tether is available. With a rear seat position where there is less to no Bowden cable on the winding shaft, there is more tether available. The more tether is available, the greater the deployment distance of the gas bag.

It is conceivable to stockpile several tethers on a winding shaft. Thus, the length of several tethers can be changed by changing the position of a winding shaft. If the winding shaft in the storage areas for the individual tethers has different diameters, different lengths of the tethers can be adjusted depending on the position of the vehicle seat. Thus, the length of several tethers can also be set differently via an airbag limiting device.

In the following the invention will be explained in more detail with reference to the embodiments illustrated in the drawings.

Showing:

1a is a schematic representation of the gas bag restraint system according to the invention with a vehicle seat associated therewith, which occupies a front seat position;

FIG. 1b shows a schematic representation of the gas bag restraint system according to the invention with a vehicle seat assigned thereto, which occupies a rear seat position; FIG. FIG. 2 shows a three-dimensional, partially sectioned representation of a gas generator for an inventive gas bag restraint system; FIG.

3 is a sectional view of a gas generator along its longitudinal axis for an inventive gas bag restraint system.

Fig. 4 is a three-dimensional representation, which is partially cut, a winding shaft for a gas generator of a gas bag restraint system according to the invention, as well as

5a, 5b, a portion of a winding shaft according to Figure 4.

In motor vehicles, gas bag restraint systems 1, which have a gas generator 2 and an airbag 3, have been used for some time. These serve to catch a vehicle occupant located on a vehicle seat 4 in the event of an accident and thus to avoid too high accelerations. If one wishes to adapt the functions of the gas bag restraint system, such as its shape or size achieved after deployment, to parameters relevant to occupant load, the invention proposes providing a mechanical coupling in the form of a Bowden cable 5. If a vehicle seat occupies a forward position relative to the cockpit or to the steering wheel of the vehicle, then it can be assumed that there is a smaller and lighter person on the seat. For this person, a gas bag with a smaller volume is sufficient. The invention is concerned with varying over the Bowden cable 5, the size of the airbag 3. When the vehicle seat 4 occupies a rear position in the vehicle, so It can be assumed that there is a larger or heavier person on the vehicle seat and a larger gas bag is needed to adequately restrain the occupant.

This is achieved in that the Bowden cable 5 engages with one end on the vehicle seat 4 and with its other end on a gas bag limiting device. The airbag-limiting device has a storage device for at least one of the deployment path of the airbag limiting tether and will be described in more detail below.

FIG. 2 shows an exemplary embodiment of a storage device for a gas bag limiting device. The storage device consists of a winding shaft 6. The winding shaft 6 is hollow and, as explained below, rotatably mounted on a gas generator 7. The gas generator 7 is a commercially available gas generator with an ignition charge, not shown, and gas outlet openings 8 through which gas can escape from the gas generator 7 for deployment of the airbag. Around the winding shaft 6 around a housing 9 is arranged. The housing 9 is also substantially cylindrical and arranged around the gas generator 7 around. It is firmly connected to the gas generator 7 via fastening elements screws 11. The housing 9 has in the region of the gas outlet openings 8 of the gas generator recesses 12, which are designed so that they ensure a trouble-free escape of the gas flow.

The gas generator 7 is arranged with the winding shaft 6 and the housing 9 as a unit in a further housing 13, which is the receptacle of the gas generator 7 and the attachment this gas generator 7 is used in the vehicle. For this purpose, the housing 13 flanges 14 with holes 15.

FIG. 3 shows the gas generator 7 in section in a housing 13. The gas outlet openings 8 in the gas generator 7 can be seen. Around the gas generator 7 around the winding shaft 6 is arranged. It is arranged rotatable relative to the gas generator 7 via bearings 16. Around the winding shaft 6 around the housing 9 can be seen, which is connected by screws 11 fixed to the gas generator 7.

The winding shaft 6 has several different areas. As can be seen from FIG. 2, the region of the winding shaft 6 situated above the gas outlet openings 8 of the gas generator 7 is provided with recesses 10 which serve to ensure unhindered escape of gas. In each case right and left of the area with the recesses 10 storage devices 17a to 17d are provided for tethers. The storage devices 17 a to 17 d consist of grooves that extend radially around the winding shaft 6 around. They have a defined diameter D, which extends over a width adapted to the tethers. In the illustrated embodiment, the diameter D of the grooves 17a to 17d are the same size. The tethers, not shown, are wound around the winding shaft 6 in the corresponding grooves 17a to 17d. Each groove 17a to 17d takes on exactly one tether. Each groove is delimited laterally and has a surface finish that always allows a reliable winding and unwinding of the tethers.

It is conceivable to make the diameters D of the grooves 17a to 17d different. In this way, via a winding shaft 6, a different length of each Tether or a different lots are provided.

On one side of the winding shaft 6, another storage device 18 connects, which serves to receive the Bowden cable 5. The storage device 18 is a part of the winding shaft 6 or according to the winding shaft 6 rotatably mounted on the gas generator 7 and fixedly connected to the winding shaft 6. It has a groove 19. The groove 19 serves to receive the Bowden cable 5. The Bowden cable 5 is fixed in the groove 19 with its one end.

In addition to the groove 19, a further groove 21 is provided in the storage device 18. This serves to receive a coil spring 22. The coil spring 22 is attached at its one end to the storage device 18 and the winding shaft 6 and with its other end to the fixed housing 9. Thus, the coil spring 22 causes the winding shaft 6, when no external forces act on them, always assumes a defined starting position.

The region 23 within the receptacle 13 above the gas generator 7 and the housing 9 serves to receive a folded gas bag, not shown.

Figure 4 shows in three-dimensional form the winding shaft 6 with the housing 9 in a sectional view. Evident are in the housing 9, the recesses 12 for the passage of the gas and receptacles 24 for the screws 11 for fixing the housing 9 to the gas generator 7. As described above, the winding shaft 6 is composed of different areas together. In the front area, the storage device 17c and 17d designed as grooves can be seen. This is followed by a perforated region with recesses 10 at. Following this perforated area further storage device 17a and 17b are provided. At this closes the storage device 18 for receiving the Bowden cable 5 and the coil spring 22 at. Evident is also the groove 19 for receiving the Bowden cable 5 and the groove

21 for receiving the coil spring 22. At the upper edge of the winding shaft 6 in the region of the groove 19, a slot 25 is introduced. In the housing 9 and in the airbag housing or the receptacle 13 is also an unillustrated entrance opening is provided either in the form of a bore or in the form of a slot for the Bowden cable 5, so that this out of the airbag housing out can be. The storage device 18 is fixedly connected to the winding shaft 6. In this case, all compounds, such as adhesive or welded joints but also positive connections such as gears in question.

Figures 5a and 5b show another embodiment of the storage device 18 ', which is shown here detached from the winding shaft 6. This storage device 18 'differs from that described above in that the groove 21 for receiving the coil spring 22 has been supplemented by a second groove 19' for receiving a second Bowden cable. The second Bowden cable can replace the coil spring

22 are used and serve to reset the winding shaft 6 in its original position. In other words, a double Bowden cable is provided, wherein each bow tie is responsible for a direction of rotation. Furthermore, two slots 26 can be seen in the drawing, which open into holes 27. The slots 26 with the holes 27 serve to receive the ends of the Bowden cables and for permanent attachment of this end to the winding shaft 6. In this way it is ensured that reliable power from the Bowden cables can be transferred to the winding shaft 6. The storage device 18 'can, as already described above, be fastened to the winding shaft 6 via conventional fastening means.

The mode of operation of the gas bag restraint system according to the invention will now be described below. By adjusting the vehicle seat 4, a force is introduced into the Bowden cable 5. This force is transmitted through the Bowden cable 5 to the winding shaft 6, so that each position of the vehicle seat 4 is associated with a defined angular position of the winding shaft 6. The winding shaft 6 is fixed in this position by the Bowden cable 5 and this oppositely acting spring 22 so that it retains this position until the vehicle seat 4 is adjusted again, especially when the gas generator 7 is ignited and the gas bag 3 unfolds. On the winding shaft 6 are stored four tethers, which are wound around the winding shaft 6 and connected at one end firmly with this. By the influence of the Bowden cable 5 on the Wickewelle 6 and taking a certain angular position, a lot is set on the tethers. Thus, the stockpiled on the winding shaft 6 tethers on the respective position of the vehicle seat 4 adapted lots. Now, if the gas bag ignited, this lot is withdrawn from the winding shaft 6 until the lots is used up and pulls the tether on the fixed winding shaft 6, but can not continue to unwind. Thus, the angular position of the winding shaft 6 determines the lots and over the length of the available tether.

There may be additional means for locking or fixing the winding shaft 6 in the set Angular position be provided. These can then be activated when the gas bag is ignited so that reliable ignition of the storage device is always possible before ignition. For example, it is conceivable to clamp the winding shaft 6 on the gas generator 7 when igniting the gas bag. This can be achieved in that the gas generator 7 is designed so that it deforms during the pressure generated during ignition and thus prevents rotation of the winding shaft 6 relative to the gas generator 7. By targeted material weakening on the gas generator 7, for example, one or more Spreizklappen open, in turn, exert pressure from inside against the winding shaft and hold them over friction and / or positive engagement. Likewise, a locking mechanism may be provided, for example in the form of a pawl, which is activated upon ignition of the gas bag and the winding shaft 6 additionally holds. The airbag flap, which opens when unfolding the gas bag can also be used to lock the winding shaft 6.

The particular advantage of the invention is the fact that all parameters are already set before the ignition of the gas bag. This is done automatically with each adjustment of the vehicle seat 4. As soon as an ignition and thus unfolding of the gas bag takes place, no variation is necessary and no parts must be moved during deployment. This leads to the system functioning reliably.

It is conceivable to provide an attenuator between the tether and the corrugation shaft 6, which serves to avoid force peaks in the tethers and to suppress excessive loading of the tethers.

Claims

claims

1. airbag restraint system (1) with an airbag (3), a gas generator (2) and an airbag limiting device that limits the maximum deployment path of the airbag (3) depending on occupant load relevant parameters, wherein the airbag-limiting device is a storage device for at least a limiting band that delimits the deployment path of the gas bag (3), characterized in that the storage device is arranged outside the gas bag (3).

2. Airbag restraint system according to claim 1, characterized in that the maximum unfolding distance in dependence on the position of the restraint system (1) associated vehicle seat (4).

3. Airbag restraint system according to claim 1 or 2, characterized in that a mechanical coupling between the position of the Vehicle seat (4) and the airbag limiting device (1) is provided.

4. Airbag restraint system according to one or more of the preceding claims, characterized in that a Bowden cable (5) is provided as a mechanical coupling.

5. Airbag restraint system according to one or more of the preceding claims, characterized in that as a storage device for the tether a

Winding shaft (6) is provided.

6. Airbag restraint system according to one or more of the preceding claims, characterized in that the winding shaft (6) in a receptacle (13) of the

Gas generator (7) is arranged.

7. Airbag restraint system according to one or more of the preceding claims, characterized in that the winding shaft (6) is rotatably mounted on the gas generator (7) and disposed within the receptacle (13) of the gas generator (7).

8. Airbag restraint system according to one or more of the preceding claims, characterized in that the winding shaft (6) with the Bowden cable (5) is connected.

9. Airbag restraint system according to one or more of the preceding claims, characterized in that the winding shaft (6) serves as a storage device for a plurality of tethers.

10. Airbag restraint system according to one or more of the preceding claims, characterized in that the winding shaft (6) has different diameters for the storage of a plurality of tethers.