DE102013005387B4 - Passenger front gas bag device - Google Patents

Abstract

Passenger front airbag device, which is arranged in or on an instrument panel (50), with a housing (10), an inflator and an airbag (14), the airbag cover (15) of which encloses a gas space (20) which can be filled by the inflator , wherein the gas bag cover (15) has a lower impact section (16) assigned to the knee-shin area of the passenger (70) to be protected and an upper impact section (17) assigned to the head-chest area, and the gas space (20) has a lower impact section Has a lower region (21) adjacent to the impact section (16) and an upper region (22) adjacent to the upper impact section (17), the lower region (21) and upper region (22) of the gas space (20) each being part of a directly connected gas space (20 ) and adaptation devices are provided which cause the effective hardness of the lower impact section (16) to be greater at least at a first time after actuation of the inflator than the effective hardness of the upper impact section (17) at a second, later time after operation of the inflator, characterized in that the housing (10) is arranged relatively far down in the instrument panel (50) and the fully expanded gas bag cover (15) extends essentially upwards from the vertical position of the housing (10), and the lower support section ( 19) there is a support section opposite, which is permanently supported on the instrument panel (50).

Description

The invention relates to a passenger front gas bag device according to the preamble of claim 1.

So-called passenger front gas bags have long been known in vehicle technology and offer good protection for the passenger in the event of a frontal collision with the motor vehicle. Such passenger front gas bags inflate using an inflator (usually a gas generator) in the event of a frontal collision between the instrument panel/windshield and the passenger. The passenger front gas bags are usually designed to have a relatively large volume and are relatively soft (i.e. with strong ventilation), so that the passenger's head and thorax can be immersed deeply in the gas bag, whereby a strong energy dissipation can take place, so that the passenger is softly supported becomes.

Such passenger front gas bags usually only offer ideal protection in conjunction with another protective device, in particular a seat belt. Such a seat belt, in particular a three-point belt, ensures, among other things, that there is no strong forward movement of the occupant's pelvis and (particularly after the force limitation of the seat belt has been inserted) that the occupant's upper body rotates into the front gas bag. Particularly in the event that it is to be expected that the front passenger is not wearing a seatbelt (this is particularly true in countries where seatbelts are not required, such as the USA), a knee airbag can help to achieve similar kinematics to that of a seatbelt to reach the passenger. This happens because the knee gas bag inflates between a lower area of the instrument panel and the knee/shin area of the occupant and thus prevents the pelvis from moving forward, so that in this case too, the occupant's upper body essentially moves into the front gas bag in a rotational movement falls in. In order to achieve this, the knee gas bag must be designed to be relatively hard.

So you can see that there is a strong interaction between the front gas bag and the knee gas bag. Since this connection exists, it has already been proposed to arrange a front passenger airbag device in the passenger area, the airbag cover of which has a lower impact section assigned to the knee/shin area of the passenger to be protected and an upper impact section assigned to the head/chest area. This means that the gas space enclosed by the gas bag has a lower region adjacent to the lower impact section and an upper region adjacent to the upper impact section. Such a passenger front gas bag device is, for example, in the generic category EP 2 457 783 A1 described. The gas space is filled via the lower area. In order to ensure that the lower impact section (i.e. that which is assigned to the knee/shin area) is harder than the upper impact section (i.e. that which is assigned to the head/chest area), the gas bag has internal throttle elements, in particular in In the form of a one-way valve. However, the coordination and production of such a gas bag is very complex. It is still problematic, despite the presence of throttle devices, to ensure that the upper area of the gas space is sufficiently filled in time to provide the protective effect for the occupant's upper body.

From the generic DE 10 2007 052 974 A1 A passenger front gas bag device is known, which is arranged on a very small instrument panel. This passenger front airbag device has a housing, an inflator and an airbag. The gas bag cover of the gas bag encloses a gas space which can be filled by the inflator. The gas bag cover has a lower impact section assigned to the knee-shin area of the passenger to be protected and an upper impact section assigned to the head-chest area, so that the gas space has a lower area adjacent to the lower impact section and an upper area adjacent to the upper impact section. The lower area and upper area of the gas space are each part of a directly connected gas space.

The DE 103 25 124 A1 shows a gas bag assigned to the head and thorax of a passenger, in which a support section and an impact section are separated from each other by a channel, so that the impact section can move overall in the direction of the support section when the passenger impacts the support section.

In the DE 10 2007 011 983 A1 A side airbag with a main gas space and a pressure relief space is described.

For example from the DE 10 2011 015 309 A1 It is known to equip an airbag with an active ventilation device. Based on this, the present invention sets itself the task of providing a generic front passenger airbag device which, on the one hand, is relatively easy to tune and produce and which On the other hand, it continues to ensure timely filling of the upper area of the gas space.

This task is achieved by a passenger front gas bag device with the features of claim 1.

According to the invention, the housing is arranged relatively far down in the instrument panel and the fully expanded gas bag cover extends essentially upwards from the vertical position of the housing. Furthermore, there is a support section opposite the lower support section, which is permanently supported on the instrument panel.

Furthermore, the upper region and lower region of the gas space are part of a directly connected gas space, which is preferably not divided by any throttle elements. A corresponding gas bag is easy to manufacture and it is also ensured that all areas of the gas space are filled quickly. Since, of course, there is still a requirement that the knee/shin area of the occupant must initially be held back very strongly, but excessive force introduction into the occupant's upper body must be avoided, adaptation devices are also provided which ensure that the effective hardness of the lower one Impact section is greater at least at a first time after actuation of the inflator than the effective hardness of the upper impact section at a second, later time after operation of the inflator.

• Zum einen ist es vertretbar bzw. gänzlich unschädlich, wenn die Härte des unteren Prallabschnitts zunächst hoch ist, dann jedoch absinkt. Die Adaptionsvorrichtung kann deshalb gemäß Anspruch 2 insbesondere durch eine aktiv betätigbare Ventilationseinrichtung gebildet sein, deren Ventilationsöffnung zunächst geschlossen oder gedrosselt ist und die zu einem Zeitpunkt nach Betätigung des Inflators aktiv - in der Regel unter Zuhilfenahme eines Aktuators - geöffnet wird, so dass Gas aus dem Gasraum nach Außen oder in einen weiteren Gasraum abströmt. Hierdurch wird natürlich auch der Druck in dem oberen Bereich des Gasraumes reduziert, was zur gewünschten Reduktion der wirksamen Härte des oberen Prallabschnitts führt. Die Feinabstimmung auf die jeweilige Fahrzeuggeometrie kann insbesondere durch Anpassung der Größe der Ventilationsöffnung der Ventilationseinrichtung und/oder durch die Wahl des Zeitpunkts, zu dem die Ventilationsöffnung geöffnet wird, erfolgen. Dieser Zeitpunkt kann fest vorgegeben sein, oder er kann von der Fahrzeug-ECU in Abhängigkeit der Unfallparameter und/oder der Größe / des Gewichts des Insassen individuell errechnet werden.

Two circumstances in particular can be taken advantage of here:

• On the one hand, it is acceptable or completely harmless if the hardness of the lower impact section is initially high but then decreases. The adaptation device can therefore be formed according to claim 2 in particular by an actively operable ventilation device, the ventilation opening of which is initially closed or throttled and which is actively opened - usually with the aid of an actuator - at a time after the inflator has been actuated, so that gas is released from the Gas space flows outwards or into another gas space. This of course also reduces the pressure in the upper region of the gas space, which leads to the desired reduction in the effective hardness of the upper impact section. The fine-tuning to the respective vehicle geometry can be done in particular by adjusting the size of the ventilation opening of the ventilation device and/or by choosing the time at which the ventilation opening is opened. This point in time can be fixed, or it can be calculated individually by the vehicle ECU depending on the accident parameters and/or the size/weight of the occupant.

Another possibility of reducing the effective hardness of the upper impact section to the desired level is to partially decouple the effective hardness of the impact section from the pressure in the gas space of the gas bag. This is achieved in that an upper region of the gas bag is designed in such a way that at least part of the upper impact section can “evade” the impacting occupant by allowing it to move overall towards the windshield/dashboard. This can be achieved according to claim 6 in particular in that at least part of the support section opposite the upper impact section of the gas bag cover is designed to be concave at least in sections. This reduces the effective support surface and therefore also reduces the retaining force at a given internal pressure. It is particularly advantageous if the upper support section has two lateral areas between which a concave intermediate section extends. The adjustment of the gas bag to the vehicle geometry takes place here in particular through the choice of the geometry of the support surface. Alternatively or additionally, support on the vehicle headliner is possible (claim 8).

The two variants just described can also be combined with each other.

Further preferred embodiments result from the further subclaims and from the exemplary embodiments now described in more detail with reference to the figures.

• 1 einen schematisierten Schnitt durch den Beifahrerbereich eines Personenkraftwagens, welcher eine erfindungsgemäße Beifahrer-Frontgassack-Einrichtung aufweist, wobei sich die Gassackhülle der Beifahrer-Frontgassack-Einrichtung in ihrem vollständig expandierten Zustand befindet,
• 2 das in 1 Gezeigte und einen Beifahrer,
• 3 einen Schnitt entlang der Ebene E-E in 2,
• 4 das in 2 Gezeigte zu einem späteren Zeitpunkt,
• 5 das in 4 Gezeigte zu einem noch späteren Zeitpunkt,
• 6 das in 5 Gezeigte zu einem noch späteren Zeitpunkt,
• 7 eine Beifahrer-Frontgassack-Einrichtung, wobei die Gassackhülle eine alternative Geometrie aufweist, in einer der 1 entsprechenden Darstellung,
• 8 eine weitere alternative Geometrie der Gassackhülle in einer der 7 entsprechenden Darstellung,
• 9 eine weitere alternative Geometrie der Gassackhülle in einer der 7 entsprechenden Darstellung,
• 10 eine zweite Ausführungsform in einer der 1 entsprechenden Darstellung und
• 11 das in 10 Gezeigte bei geöffneter Ventilationseinrichtung.

The invention will now be described in more detail using exemplary embodiments with reference to the figures. Show here:

• 1 a schematic section through the passenger area of a passenger car, which has a passenger front gas bag device according to the invention, the gas bag cover of the front passenger front gas bag device being in its fully expanded state,
• 2 this in 1 Shown and a passenger,
• 3 a section along the plane EE in 2 ,
• 4 this in 2 Shown at a later date,
• 5 this in 4 Shown at a later date,
• 6 this in 5 Shown at a later date,
• 7 a passenger front gas bag device, wherein the gas bag cover has an alternative geometry, in one of 1 corresponding representation,
• 8th another alternative geometry of the gas bag cover in one of the 7 corresponding representation,
• 9 another alternative geometry of the gas bag cover in one of the 7 corresponding representation,
• 10 a second embodiment in one of the 1 corresponding representation and
• 11 this in 10 Shown with the ventilation device open.

The 1 shows a highly schematic cross section through the passenger area of a passenger car. The cutting plane is vertical and extends in the longitudinal direction of the vehicle. The instrument panel 50, the windshield 52, the roof with the vehicle headliner 54 and the passenger seat 60 are shown. A passenger front gas bag device is arranged in or on the instrument panel 50. This has a housing 10, a gas generator 12 serving as an inflator and a gas bag 14. In 1 the gas bag cover 15 of the gas bag 14 is shown in the fully expanded state. The housing 10 is arranged relatively far down in the instrument panel 50 and the fully expanded gas bag cover 15 extends essentially upwards from the vertical position of the housing 10. Since the passenger front gas bag device is intended to serve both to restrain the knee/shin area and to catch the passenger's upper body, the impact surface of the gas bag cover 15 has a lower impact section 16 and an upper impact section 17. In the exemplary embodiment, as in 1 is shown, the two sections of the impact surface just mentioned are relatively sharply separated from one another by a kind of bend or step; however, this is not necessarily mandatory. The gas bag cover 15 encloses a contiguous gas space 20, the area of the gas space which is adjacent to the lower impact section 16 being referred to as the lower area 21 and the area which is adjacent to the upper impact section 17 being referred to as the upper area 22. The upper and lower areas are not separated from each other by throttle elements, overflow valves or the like.

Like any other gas bag cover, the gas bag cover of course not only has impact sections, but also support sections. Here, the lower impact section 16 is essentially opposite the lower support section 19, which is permanently supported on the instrument panel. The upper support section 18 (which is essentially opposite the upper impact section 17) has a special shape, which is particularly good 3 can be removed. The upper support section 18 namely has two lateral regions 18a, 18b and an intermediate region 18c located between the lateral regions. Here, the intermediate area 18c is curved inwards, i.e. in the direction of the vehicle seat, so an indented area is created in which the support surface is concave. In cross section, as in 3 As shown, the result is a U-shape (this could also be described as dromedary-shaped or saddle-shaped). The following should be emphasized at this point: The upper part of the gas bag cover is supported entirely or predominantly on the side areas 18a, 18b of the upper support section 18; There is almost no support in the intermediate area 18c. Nevertheless, the definitions made here are chosen such that the intermediate region 18c is defined as belonging to the upper support section 18 of the gas bag cover 15. The region of the upper impact portion 17, which is opposite the intermediate region 18c of the upper support portion 18, is referred to as the middle region 17a. This is the area where an occupant's chest and head impact in a straight frontal crash.

An active, adaptive ventilation device is also provided. Its ventilation opening 26 is closed or throttled in an initial state and in a final state it allows gas to flow out of the gas space 20 to the outside. Such an adaptive ventilation device usually (and here too) has, in addition to the ventilation opening 26, a cover or closure element which throttles or closes this ventilation opening 26 in an initial state and an actuator (not shown in the figures) which interacts with the cover or closure element. on, whereby a (usually electrical) actuation of the actuator causes the ventilation opening to no longer be closed by the cover or closure element. Various constructive solutions are known in the prior art for this purpose.

In the exemplary embodiment shown, the cover or closure element is a grommet 28. Such an adaptive ventilation device is, for example, from US 6648371 known, the disclosure content of which is hereby explicitly referred to becomes. The grommet 28 is connected to the gas bag cover 15 at one end around the ventilation opening 26 and the end of the grommet 28 facing away from the gas bag casing carries a tension element 29, which holds the grommet inside the gas space, provided that the tension element 29 is under tension, whereby the Ventilation opening is closed or at least heavily throttled. The end of the tension element 29 facing away from the grommet is connected to the housing in the initial state and is separated from the housing in response to an electrical signal when an actuator is actuated. This fastening of the tension element to the housing (or another vehicle-fixed component), which can be detached in response to a signal, can also be done, for example, as in DE 10 2011 014 869 A1 described, be designed, whereby the actuator that causes this release works pyrotechnically. The length of the tension element 29 is dimensioned such that when the gas bag cover 15 is in its fully expanded state, it is under tension and thus holds the grommet 28 inside the gas space, thereby preventing gas from flowing out through the ventilation opening 26 , so that the ventilation device is in a closed or heavily throttled state. The ventilation opening 26 is preferably located in a section of the gas bag cover facing the side window. If the end of the tension element, which is initially coupled to the housing, is released due to the actuation of the actuator, the nozzle is pushed outwards through the ventilation opening due to the internal pressure and gas can flow out through the ventilation opening. Other types of adaptive ventilation devices can of course also be used. For example, adaptive ventilation devices can be used in which the actuator is carried by the gas bag cover, or also those in which no separate cover or closure element is provided. The only important thing is that the ventilation opening is brought from an originally closed, closed or throttled state into an open state due to a - usually electrical - signal. Preferably (this applies to all embodiments) the ventilation opening of the active ventilation device is located in the upper region of the gas bag cover, i.e. adjacent to the upper region of the gas space.

The functionality of the passenger front gas bag device will now be explained with reference to the 2 until 6 explained. If a frontal impact of sufficient magnitude is detected, the gas generator 12 is ignited and the gas bag cover 15 of the gas bag 14 inflates in front of the passenger 70. 2 shows an average occupant in a standard sitting position, for example a 50% man. Here, the lower impact section 16 of the gas bag cover 15 comes into direct contact with the knee/shin area of the passenger 70, even if the passenger has not yet moved out of his sitting position. In the exemplary embodiment shown, the head or chest is not yet connected to the upper impact section 17 ( 2 and 3 ). The ventilation opening 26 is initially closed. There is a relatively strong gas generator, so that the pressure in the gas space 20 enclosed by the gas bag cover 15 is preferably between 0.4 and 1 bar.

Due to the negative acceleration of the vehicle, the occupant 70 now moves towards the gas bag cover 15, with the knee/shin area being held back due to the lower impact section. This also results in a restraint of the hip area. The retention is usually not perfect, that is, there is some forward displacement of the pelvis, as in 4 is also shown. In addition to this translational movement, which cannot be completely avoided, a rotational movement of the occupant's upper body continues to take place around the hip, which means that the upper body "tips" into the upper impact section 17 of the gas bag cover 15. This also shows 4 . At an early stage of this "tilting in" the ventilation opening 26 can still be closed by the grommet 28, but this is then released by the end of the tension element 29 facing away from the grommet being released in response to an electrical signal and the grommet thereby being pushed through Ventilation opening 26 is inverted and gas can flow out of the gas space, whereby the gas bag cover becomes softer overall and in particular the effective hardness of the upper impact section is reduced. The pressure preferably drops to 0.3 to 0.6.

However, the effective hardness of the upper impact section is anyway lower than the effective hardness of the lower impact section, since the upper region of the gas bag shell 15 can move in the longitudinal direction of the vehicle due to the previously described geometry of the upper support section, which is not possible for the lower region of the gas bag shell is; There is therefore a certain “tilting movement” of the gas bag cover in the direction of travel, as is particularly the case in 6 you can see. The upper support section 18 is supported here via the windshield 52.

The 4 until 6 one can see a further advantage of the passenger front gas bag device according to the invention, which is that the gas bag cover 15 presses on the thighs of the occupant to be protected in an area between the upper and lower impact surfaces, which improves his restraint and in-position posture. The friction that occurs continues to contribute to the desired energy dissipation.

The embodiment just described combines two methods to achieve that the effective hardness of the upper impact section at a later time is greater than the effective hardness of the lower impact section at an earlier time. These two methods are active ventilation and the choice of the geometry of the upper support surface. It is usually preferable to combine both methods, but it is also possible to use only one of the two methods.

In the exemplary embodiment shown, only one adaptive ventilation device is provided, but this is not mandatory: On the one hand, it is possible to additionally provide a permanently open ventilation opening; Furthermore, it is possible to provide a further adaptive ventilation device, which is actuated (i.e. opened) in particular when a light person is sensed (which is possible, for example, if a corresponding weight sensor is installed in the seat).

The 7 until 9 show variations on what has just been shown: On the one hand, for example, it is possible ( 7 ), to design the upper area of the gas bag cover 15 with greater depth, so that the head and chest are coupled at a time when the occupant has not yet moved in the direction of travel. It is also possible ( 8th ), that the gas bag cover is supported on the vehicle headliner 54 at least at the beginning of the restraint process by means of a roof support section 86. When the upper area of the gas bag cover "evades" when it hits the occupant's upper body, this "roof support section 86 rubs along the vehicle headliner, which contributes to the desired energy dissipation. Original support on both the vehicle headliner and the windshield is also possible ( 9 ).

The 10 and 11 show a second embodiment. The difference to the first exemplary embodiment is that when the adaptive ventilation device is actuated, the gas does not flow out of the gas space 20 to the outside, but into a further gas space 80, which is initially not filled. The adaptive ventilation device can be designed as in the first exemplary embodiment. To form the further gas space, an additional layer 82 is arranged, for example sewn, on the gas bag cover 15 enclosing the gas space.

In the exemplary embodiment shown, this further layer is located in front of the middle region 17a of the upper impact section. This has the further advantage that the occupant (particularly his head) is reliably prevented from bottoming out even when the concave region of the upper impact section is very deep.

Reference symbol list

10

Housing

12

Gas generator

14

Gas bag

15

Gas bag cover

16

lower impact section

17

upper impact section

17a

middle area

18

upper support section

18a,b

lateral area

18c

Intermediate area

19

lower support section

20

gas room

21

lower area of the gas space

22

upper area of the gas space

22a,b

lateral section

26

Ventilation opening

28

grommet

29

Tension element

50

dashboard

52

windshield

54

Vehicle headliner

60

Passenger seat

70

passenger

80

further gas space

82

Additional layer

86

Roof support section

Claims (8)

Passenger front airbag device, which is arranged in or on an instrument panel (50), with a housing (10), an inflator and an airbag (14), the airbag cover (15) of which encloses a gas space (20), which is fed through the inflator can be filled, the gas bag cover (15) having a lower impact section (16) assigned to the knee-shin area of the passenger (70) to be protected and an upper impact section (17) assigned to the head-chest area, and the gas space (20) one the lower impact section (16) adjacent lower region (21) and an upper region (22) adjacent to the upper impact section (17), the lower region (21) and upper region (22) of the gas space (20) each being part of a directly connected gas space (20 ) and adaptation devices are provided which cause the effective hardness of the lower impact section (16) to be greater at least at a first time after actuation of the inflator than the effective hardness of the upper impact section (17) at a second, later time after operation of the inflator, characterized in that the housing (10) is arranged relatively far down in the instrument panel (50) and the fully expanded gas bag cover (15) extends essentially upwards from the vertical position of the housing (10) and the lower support section (19) there is a support section opposite, which is permanently supported on the instrument panel (50). Passenger front gas bag device Claim 1 , characterized in that the adaptation devices have at least one active ventilation device, the ventilation opening (26) of which is closed or throttled in an initial state, in particular by means of a cover or closure element, and which is open in a final state and through which gas is released from the gas space in the final state (20) flows outwards or into another gas space (80). Passenger front gas bag device Claim 2 , characterized in that the active ventilation device has an electrically actuated actuator. Passenger front gas bag device Claim 2 or Claim 3 , characterized in that the active ventilation device is actuated after the inflator has been actuated. Passenger front gas bag device according to one of the Claims 2 until 4 , characterized in that an additional layer (82) is arranged on the gas bag cover, so that a further gas space (80) is formed between a section of the gas bag cover and the additional layer, which is connected to the gas space (20) when the ventilation device is actuated, so that gas flows from the gas space (20) into the further gas space (80). Passenger front airbag device according to one of the preceding claims, characterized in that the adaptation devices have an upper support section (18) which is concave at least in sections and is opposite the upper impact section (17) of the airbag cover (15). Passenger front gas bag device Claim 5 and Claim 6 , characterized in that the additional layer (82) is arranged in front of a concave region (18c) of the support section (18) on the gas bag cover (15). Passenger front gas bag device according to one of the preceding claims, characterized in that the adaptation device has a roof support section (86) which rests on the vehicle headliner (54).

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