WO2005113299A1

WO2005113299A1 - Motor vehicle comprising a knee airbag, and knee airbag for integrating into a motor vehicle

Info

Publication number: WO2005113299A1
Application number: PCT/EP2005/004789
Authority: WO
Inventors: Arno Gruber; Marco Broussard
Original assignee: Autoliv Development Ab
Priority date: 2004-05-07
Filing date: 2005-05-03
Publication date: 2005-12-01

Abstract

The invention relates to a knee airbag (10) for a motor vehicle and a motor vehicle comprising one such knee airbag. The inventive knee airbag (10) comprises an impact surface (12) and inflates, as required, in the direction of the knee and shin areas of a passenger. The aim of the invention is to improve the protection of the passenger. To this end, the knee airbag (10) is embodied and arranged in such a way that, for a 50 % H III dummy in a standard sitting position, the impact surface (12) surrounds the knee and shin area of the dummy with a defined geometry.

Description

tools with a Koie gas bag and knee gas bag for installation in a motor vehicle

description

Technical field of the invention

The invention relates to a motor vehicle with a knee gas bag according to the preambles of claims 1, 3 and 5, and a knee gas bag for installation in a motor vehicle according to claim 13.

The use of knee gas bags in motor vehicles is known. Such knee gas bags together with a driver or front passenger airbag and a belt system serve to protect the occupant in the event of a frontal crash or a laterally offset frontal crash. The knee airbag has two main tasks: First, it is intended to prevent the occupant's knee-shin area from hitting the interior structure of the vehicle. A knee airbag also has the task of holding the occupant in his sitting position in the event of a head-on collision. He normally shares this task with the belt system; Ideally, however, the knee airbag should be designed in such a way that it keeps the occupant in position - at least to a limited extent - even when the seat belt is not fastened.

As with other gas bags, when dimensioning and positioning the knee gas bag, a compromise has to be made between maximum restraint performance and minimal possible injury from the gas bag itself. It should also be taken into account here that the potential occupants can be of different sizes and weights and can also assume different sitting positions. The size and position of gas bags are therefore usually shown on standard dummies in standard Sitting positions designed. This approach is also chosen for the following, assuming a 50% H III dummy in the standard sitting position. The standard seating position is the seating position of a medium-sized person, as designed by the automobile manufacturer, in particular the position provided by the US legislation FMVSS 208.

As already mentioned, when airbags are deployed, a compromise must always be made between the maximum restraining effect and the minimal load on the occupant by the airbag. Due to the mostly confined spatial conditions in the footwell of a passenger car, this applies in particular to a knee gas bag.

State of the art

Up to now, knee gas bags have mostly been arranged in such a way that their baffles, when the gas bag is completely filled, are located in a standard dummy in the standard sitting position just before the knee-shin area of the dummy, or lie slightly against it. As a result, the knee-shin area is not stressed, but the restraining effect is also relatively low, which has a particularly negative effect if no seat belt is worn.

The DT 2 109 637 C3 shows, among other things, a knee gas bag that expands so far into the car that it wraps around almost the entire knee-shin area of the occupant. Such a knee airbag can certainly achieve a good restraining effect, but the airbag itself has to put up with a very large load on the occupant. It is also difficult to fill such a large-volume gas bag. Subject of the invention

Starting from this prior art, it is the object of the invention to develop a generic motor vehicle in such a way that a good and early onset restraining effect is achieved by a knee gas bag without having to put up with excessive stress on the occupant by this gas bag.

This object is achieved by a motor vehicle with the features of claims 1, 3 or 5, or by a knee gas bag with the features of claim 13.

It was recognized that the object can be achieved in that the knee gas bag is designed and positioned in such a way that at least the outer upper knee-shin regions of the occupant are wrapped around to a defined extent. On the one hand, an insufficient wrap would lead to a restraining effect starting too late or a weak restraining effect at the beginning of the forward displacement. On the other hand, the depth of the knee gas bag must also not be chosen too large, since otherwise there is a considerable risk of injury to the occupants from the knee gas bag itself, particularly if the occupants are sitting too far forward. Furthermore, an airbag that is too large and can reasonably be filled with gas can only be filled with difficulty in a sufficiently short time. The degree of looping found experimentally and specified in claim 1 fulfills these boundary conditions. Due to the wrapping of the knee-shin area, the knees of the occupant are held back very early, so that a forward movement of the occupant is avoided. As a result, the power transmission of the knee gas bag to the occupants is significantly reduced overall.

Alternatively or preferably in addition to this, the upper knee-shin areas are not only the outside but also the inside entwined. A corresponding design of the knee gas bag not only improves the restraining effect, but also brings about very good fixation of the legs in the transverse direction, which contributes to improved occupant protection in the event of a laterally offset oblique impact. In this case, the wrap around the inner knee-shin regions is preferably essentially as large as the wrap around the outer knee-shin regions.

It was also recognized that the load on the occupant by the knee gas bag depends not only on the total force transmitted, but also on exactly where the force is transmitted. For anatomical reasons, it is preferable that as large a part of the force transmission as possible takes place in the area of the knee and as small a part of the force transmission as possible in the area of the tibia. Following this finding, in a further preferred exemplary embodiment according to claim 9, a knee gas bag is provided which at least partially wraps around the knee-shin area of the occupant (or of the dummy), to be precise in an upper area than in a lower area. With the same internal pressure in the entire knee gas bag, this relieves the shin area from the knee area.

In order to avoid pressure peaks, the impact surface of the knee gas bag should preferably be flat or convex.

The concept presented here makes it possible to use a knee gas bag having only one chamber, without having to forego the advantages according to the invention. This is of course preferable from a manufacturing point of view.

Further preferred embodiments result from the further subclaims and from the exemplary embodiments now shown in more detail with reference to the figures. Here show: Brief description of the drawings

1 shows a completely filled knee gas bag and the leg of an occupant or dummy, FIG. 2 shows a section along the line A-A in FIG. 1,

FIG. 3 shows a section along the line B-B in FIG. 1,

FIG. 4 shows an illustration of the prior art,

FIG. 5 shows a further illustration of the prior art,

FIG. 6 shows a knee gas bag with an essentially vertical tether,

Figure 7 shows an asymmetrical embodiment.

Description of preferred embodiments

FIG. 1 shows a completely filled knee gas bag 10 fastened on the passenger side to an inner structure I, which has an impact surface 12. Leg B corresponds to the position of a 50% h ill dummy in its standard sitting position. The dummy sits in its H point. A large part of the baffle surface 12 is flat and bulges convexly at the end of an upper region 12a or lower region 12b.

In this exemplary embodiment, the geometry and position of the knee gas bag 10 are selected such that the baffle surface 12 wraps around the knee-shin area of the 50% H III dummy more strongly in an upper region 12a than in one when the knee gas bag 10 is completely filled lower area 12b. The degree of wrap preferably decreases continuously, as is also shown in this exemplary embodiment.

According to the invention, at least the outer upper knee-shin areas are wrapped by the baffle 12 of the knee gas bag. In the preferred embodiment shown here, both the upper and the lower knee-shin areas are wrapped. Farther The baffle 12 also curves in the area between the knees / shins of the occupant in the direction of the occupant, which means that the inner knee-shin areas are also wrapped around.

Figures 2 and 3 are sections along the section lines AA and BB in Figure 1. Figure 2 shows an upper, Figure 3 shows a lower knee shin area. To define the degree of wrap, straight line g is used, which extends horizontally and perpendicularly to vehicle longitudinal axis f. The angle α is now used as a measure of the degree of the wrap, in which the imaginary tangential planes 15, 15 ', 15 ", 15"' (see FIGS. 2 and 3) are at straight line g. By definition, these tangential planes have the orientation of the impact surface 12 along the line at which the contact of the impact surface 12 begins at the knee-shin region. The angles cti and α-t 'denote the intersection angles of those tangential areas which relate to the outer knee-shin region, the angles α ₂ and α ₂ denote the intersection angles of those tangential surfaces which relate to the inner knee-shin region.

In the exemplary embodiment shown here, the knee gas bag 10 is symmetrical, which means that the angle α relating to the leg B _a outside the vehicle is exactly as large as the angle α relating to the leg Bj outside the vehicle.

In the upper knee-shin region shown in FIG. 2, the angle CH (outside of the knee-shin region) is between 15 ° and 75 °, preferably between 35 ° and 55 °. The angle α ₂ (inside) is in the same range and is preferably the same size as the angle α-t.

In a lower knee-shin area (FIG. 3), the wrap decreases compared to the upper area, that is, the corresponding angles become smaller: α-T <αi, α ₂ '<α ₂ . In some applications, it may make sense not to design the knee gas bag symmetrically, namely in particular in that the leg outside the vehicle is wrapped more tightly than the leg inside the vehicle: α-ι (Ba)> α-ι (Bj). This increases the restraining effect on the outside of the vehicle and directs the occupant away from the outside structure of the vehicle in the event of a laterally offset oblique impact (FIG. 7).

In order to achieve the necessary depth of the knee gas bag without having to fill an excessively large volume, it can make sense to provide a tether 28 that runs essentially vertically through the gas bag, as shown in FIG.

FIGS. 4 and 5 show the state of the art to clarify the innovation.

It has heretofore been proposed either to wrap the entire knee-shin area strongly (FIG. 4), or to avoid wrapping the wrap more or less completely (FIG. 5).

Claims

claims

1. Motor vehicle with an impact surface (12) having a knee airbag (10), the airbag inflating if necessary in the direction of the knee-shin regions of an occupant and the impact surface at least partially wrapping around the knee-shin regions, characterized in that the The knee gas bag (10) is designed and positioned in such a way that, in the case of a 50% H III dummy in the standard seating position, at least the tangential surfaces (15) of the baffle surfaces (12) assigned to the outer upper knee-shin area with a horizontal and perpendicular to the vehicle longitudinal axis (f) include a first angle (α-i) between 15 ° and 75 °.

2. Motor vehicle according to claim 1, characterized in that the first angle (αi) is 35 ° to 55 °.

3. Motor vehicle with a knee gas bag (10) having a baffle surface (12), the gas bag (10) inflating in the direction of the knee-shin area of an occupant if necessary and the baffle surface (12) at least partially wrapping around the knee-shin area , characterized in that the knee gas bag is designed and positioned so that with a 50% H IM dummy in the standard seating position the impact surface also wraps around the inner knee-shin area.

4. Motor vehicle according to claim 3, characterized in that at least the tangential surfaces (15 ') of the impact surfaces assigned to the inner upper knee-shin regions with a straight line running horizontally and perpendicularly to the longitudinal axis of the vehicle each have a second angle (α ₂ ) between 15 ° and Include 75 °.

5. Motor vehicle, characterized in that it has the features of claim 1 or claim 2 and the features of claim 3 or claim 4.

6. Motor vehicle according to claim 5, characterized in that the first and second angles belonging to a knee-shin region are substantially the same size.

7. Motor vehicle according to claim 6, characterized in that all first and second angles are substantially the same size.

8. Motor vehicle according to one of claims 1 to 5, characterized in that the knee gas bag is designed and positioned so that the outer upper knee-shin area of the leg facing the vehicle outside is wrapped more strongly by the impact surface than the outer upper Knee-shin area of the leg facing the inside of the vehicle.

9. Motor vehicle according to one of the preceding claims, characterized in that the knee gas bag (10) is designed and positioned such that the wrapping of the knee-shin region decreases from top to bottom with a 50% H III dummy in the standard seating position.

10. Motor vehicle according to one of the preceding claims, characterized in that the impact surface (12) in the filled, unloaded state has only flat or convex areas.

11. Motor vehicle according to one of the preceding claims, characterized in that the knee gas bag has exactly one chamber.

12. Motor vehicle according to one of the preceding claims, characterized in that at least one essentially vertical tether (28) extends through the knee gas bag.

13. Knee airbag for installation in a motor vehicle, characterized in that it is designed for installation in a motor vehicle according to one of claims 1 to 11.