DE102014007035A1 - Knee bag, knee bag module and knee bag module arrangement in a motor vehicle - Google Patents

Abstract

A knee airbag (50) is described. This knee airbag (50) extends in a longitudinal direction from a front end (50a) to a rear end (50b). It has a baffle wall and a support wall, which are connected to each other by means of a peripheral edge connection. In its fully inflated state, which is free of external forces, the knee airbag (50) assumes a curved or kinked shape such that the baffle wall as a whole is generally convex in the longitudinal direction and the support wall is generally concave in the longitudinal direction. In order to be able to produce the knee airbag as a whole simply, the baffle wall has at least one fold (22, 24) extending transversely to the longitudinal direction, the two ends of which are closed, so that the baffle wall at least in the unexpanded state in the region of the at least one fold (22 , 24) has an omega-shaped cross-section.

Description

The invention relates to a knee airbag according to the preamble of claim 1, a knee airbag module according to claim 9 and a knee airbag module arrangement according to claim 11.

So-called knee gas bags have been used in the automotive industry for some time. They serve to prevent contact of the knee-shin area of the driver or the passenger with the instrument panel and to counteract a forward displacement of the pelvis in a frontal impact.

Such a knee airbag always extends (relative to the rolled out or expanded state) from a front end to a rear end. Such a knee airbag has two layers, namely the baffle wall and the support wall. In the assembled and expanded state in this case shows the baffle to the occupant, in particular to the knee-tibia area, and the support wall faces the instrument panel and is usually at least in sections on this.

A knee airbag is in the state in which it is mounted in a motor vehicle, part of a knee airbag module, which next to the knee airbag an inflator (usually in the form of a gas generator) and a housing in which the knee airbag is folded, has. In so-called "low-mount" gas bag modules, the housing is located in the lower area of the instrument panel or in a transition area between the instrument panel and footwell ceiling or it forms a portion of the footwell ceiling. The opening of the housing, through which the knee airbag exits when the inflator is actuated, frequently points downward or diagonally downwards. Such a "low-mount" -Kiegiegackmodul is for example from the DE 10 2006 040 177 B4 known. In such a "low-mount" gas bag module, the knee airbag is connected in the region of a front end with its housing and extends in the expanded state from this first end against the direction of travel in the direction of the occupant to be protected.

In particular, when such a "low-mount" geometry is selected, it is usually necessary that the knee airbag in the expanded state assumes a kinked or bent shape such that the gas bag viewed from the side or in a longitudinal section a "banana shape" occupies. In other words, the baffle must be overall convex in the longitudinal direction and the support wall must be concave in the longitudinal direction as a whole, so that the assembled and expanded airbag in the direction of travel extends backwards and upwards.

The generic DE 10 2007 005 304 A1 shows such a "banana-shaped" knee airbag. The curved shape is created by sewn into the support wall folds, which shorten the support wall relative to the baffle wall. In this way, although the desired shape is achieved, however, a disadvantage is a relatively high production cost, which is due in particular to the fact that the introduction of the folds in the support wall can be made only when baffle and support wall are connected to each other, in particular sewn.

On this basis, the present invention has the object, a generic knee bag, to further develop the effect that its production is simplified.

This object is achieved by a knee airbag having the features of claim 1.

In claim 9, a knee airbag module with such a knee airbag and in claim 11 is a knee air bag module arrangement indicated with such a knee airbag.

Even with the knee airbag according to the invention, the desired curvature is generated by folding, in contrast to the prior art, but not by folding the support wall, but by folding the baffle, namely such that the baffle has at least one transverse to the longitudinal extension extending fold, the two ends are closed, preferably by sections of the edge connection. This gives the baffle in the region of the fold an omega-shaped cross-section.

The advantage lies in a very simple production process, since the necessary fixation can take place simultaneously with the connection (usually stitching) of the baffle with the support wall, whereby a very simple sewing process can be realized, as will be described later with reference to the embodiment described in detail will see.

Upon expansion of the airbag folds the at least one fold - preferably more than one fold provided - except in the edge region (here the fold remains closed) which forms a partial extension of the baffle against the support wall, which leads to the desired curvature.

By arranging simple separating seams, the space enclosed by the gas bag can be divided into several chambers, which is often preferred. In this case, it is particularly preferred that there is a separating seam between the two folds.

Preferably, the gas bag can be designed completely without inner tethers, which further contributes to its production simplification.

The invention will now be explained in more detail by means of embodiments with reference to the figures. Hereby show:

1 : two blanks, which are sewn to a knee airbag,

2 : the finished, from the two blanks of the 1 sewn knee airbag in a flat, but not blown out condition and a gas generator,

3 : a section along the plane AA in 2 .

4 : the knee airbag off 3 and a gas generator located in the knee airbag, wherein the knee airbag is in its expanded state,

5 A second embodiment of the knee airbag according to the invention in one of 2 appropriate representation,

6 : a section along the end BB in 5 .

7 : the knee airbag off 6 and a gas generator located in the knee airbag, wherein the knee airbag is in its expanded state,

8th A variant of the second embodiment in one of 5 corresponding representation and

9 a knee airbag module mounted in a motor vehicle, the knee airbag of which is in its fully expanded state.

The 1 shows a first cut 10 and a second blank 20 , wherein the first blank 10 in the finished sewn and mounted knee airbag, the supporting wall and the second blank 20 forms the baffle. In the embodiment shown, two separate blanks are provided, but it would also be possible to provide a common blank so that it would have a first portion for forming the support wall and a second portion for forming the baffle.

In the illustrated embodiment, both blanks 10 . 20 rectangular, so each have a first edge 10a . 20a , a second edge 10b . 20b , a third edge 10c . 20c and a fourth edge 10d . 20d on. The two blanks are the same width, but different lengths, ie, that the distance of the first edge 10a to the third edge 10c of the first blank is smaller than the distance of the first edge 20a to the third edge 20c of the second blank 20 , In other words, the extent of the two blanks in the X direction (transverse direction) is the same, the extension in the Y direction (longitudinal direction) is not. Adjacent to the first edge 10a of the first blank 10 are two openings 12a . 12b provided for gas generator bolts and another opening for the introduction of a gas generator.

In a first processing step, at least one fold is folded into the second blank, in the described embodiment, two such folds 22 . 24 intended. These folds are perpendicular to the longitudinal extent of the second blank 20 (ie, in the X direction) and each extend from a first end to a second end, with the first end on the second edge 20b and the second end on the fourth edge 20d rests. After creating these folds, the two blanks 10 . 20 by means of an edge connection, in particular an edge seam 30 , connected to each other, whereby the resulting gas bag is formed in sections four-ply, the support wall is single-ply and the baffle wall sections in three layers.

Because the blanks 10 . 20 in the embodiment shown are rectangular, thus also has the edge seam corresponding to four sections, namely the first section 30a , the second section 30b , the third section 30c and the fourth section 30d , Sections of the second section 30b and sections of the fourth section 30d close the lateral ends of the folds 22 . 24 so the gas bag 50 enclosed on all sides (with the exception of the openings 12a . 12b and 14 in the first cut 10 ). In the area of the ends of the folds are in each case three layers of the baffle wall by the edge seam 30 connected with each other.

How to especially the 3 can take, have the wrinkles 22 . 24 in the flat but not inflated state of the gas bag 50 two outer folding edges 22a . 22b . 24a . 24b and two inside fold edges 22c . 22d and 24c . 24d , Thus, an omega-shaped cross section of the baffle wall results in the area of the folds.

The 4 shows the expanded state, ie the state in which the space which is enclosed by the blanks, by gas from the gas generator 40 is filled. As the wrinkles 22 . 24 - Except at the edges, at which the folding edges by the edge seam 30 secured and closed - bulge, which extends through the second blank 15 formed baffle 25 across from the first cut 10 formed support wall 15 , which sets the desired, curved cross-section.

The 5 to 7 show a second embodiment of the knee airbag according to the invention. They are separating seams 61 . 62 (In the embodiment shown two pieces) present, which are substantially parallel to the first and the third section 30a . 30c extend the edge seam and subdivide the space enclosed by the gas bag in chambers (in the embodiment shown three). The second separation seam 62 runs here between the two folds 22 . 24 , How to get the 5 removes, run the two separating seams 61 . 62 in each case not up to the lateral edges of the knee airbag 50 such that the first chamber K1 and the second chamber K2 and the second chamber K2 and the third chamber K3 are each laterally in fluid communication. These separating seams make the gas bag more contoured ( 7 ), which can be advantageous and improve the formation of the curvature. The arrangement of the separating seams increases the production cost only insignificantly.

In a variation, as in 8th As shown, the seperation seams 61 . 62 also several sections 61a . 61b ; 62a . 62b exhibit.

The curvature can be adjusted by the length ratio between the first and second blank. Thus, the gas bag can be easily adapted to the geometric conditions of a motor vehicle ("tuning").

Everything that has just been described would also apply if the airbag cover were folded out of a blank. It should also be emphasized that although the case of a rectangular support wall and thus also of a rectangular baffle wall is the simplest in terms of geometry, the folding according to the invention can be applied to other geometries.

The 9 shows an airbag module with a knee airbag according to the invention (shown is the gas bag of the second embodiment, the now explained also applies to other embodiments of the knee airbag invention) in a built-in motor vehicle condition, the gas bag by the gas generator 40 completely inflated. The gas generator is located (as already in the 4 and 7 shown) near the front end 50a the knee airbag 50 and is by means of its gas generator bolts 42 with a housing 70 connected. The housing is located in a lower section of the instrument panel, in a transition area between the instrument panel and footwell ceiling 82 (as shown) or forms a portion of the footwell ceiling. The in the initial state with a door 74 closed outlet 72 has substantially downwards, but may also point obliquely downwards and in the direction of the vehicle rear. It can be seen that the knee airbag due to its curvature of the shape of the lower portion of the instrument panel 80 follows, leaving the support wall 15 is positioned in front of the instrument panel.

LIST OF REFERENCE NUMBERS

10

first cut

10a

first edge

10b

second edge

10c

third edge

10d

fourth edge

12a, b

Opening for gas generator bolts

14

further opening

15

supporting wall

20

second cut

20a

first edge

20b

second edge

20c

third edge

20d

fourth edge

22

first fold

22a, b

external folding edge

22Cb

inside folded edge

24

second fold

24a, b

external folding edge

24b, c

inside folded edge

25

baffle wall

30

fillet

30a

first section

30b

second part

30c

third section

30d

fourth section

40

inflator

42

Inflator pin

50

Knee airbag

50a

front end

50b

rear end

61

first separating seam

62

second separating seam

70

casing

72

outlet opening

74

door

80

dashboard

82

footwell ceiling

84

ground

K1

first chamber

K2

second chamber

K3

third chamber

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102006040177 B4 [0004]
• DE 102007005304 A1 [0006]

Claims (11)

Knee airbag ( 50 ) which extends in a longitudinal direction from a front end ( 50a ) to a rear end ( 50b ) and which a baffle wall ( 25 ) and a support wall ( 15 ), which are connected to each other by means of a circumferential edge connection, wherein the knee airbag in its fully inflated, free from external forces state assumes a bent or kinked shape such that the baffle wall ( 25 ) in the longitudinal direction convex and the support wall ( 15 ) in the longitudinal direction is concave, characterized in that the baffle wall ( 25 ) at least one transverse to the longitudinal direction extending fold ( 22 . 24 ) whose two ends are closed, so that the baffle wall ( 25 ) at least in the unexpanded state in the region of the at least one fold ( 22 . 24 ) has an omega-shaped cross-section. Knee bag according to claim 1, characterized in that the two ends of the pleat ( 22 . 24 ) are closed by sections of the edge connection, so that in the region of the ends of the folds ( 22 . 24 ) three layers of the baffle wall ( 25 ) are interconnected. Knee bag according to claim 1 or claim 2, characterized in that the baffle wall ( 25 ) at least two parallel folds ( 22 . 24 ) having. Knee bag according to one of the preceding claims, characterized in that the edge connection is an edge seam ( 30 ). Knee bag according to one of the preceding claims, characterized in that baffle ( 25 ) and supporting wall ( 15 ) are connected only by seams or only by seams and a fold line. Knee bag according to one of the preceding claims, characterized in that transversely to the longitudinal direction at least one separating seam ( 61 . 62 ), which the baffle wall ( 25 ) and the supporting wall ( 15 ) and thus divides the space enclosed by the gas bag into two chambers in fluid communication with each other. Knee bag according to claim 6, characterized in that two separating seams ( 61 . 62 ) are present, so that three chambers (K1, K2, K3) are formed. Knee bag according to claim 3 and one of claims 6 or 7, characterized in that a separating seam ( 62 ) between the two folds ( 22 . 24 ) is located. Knee airbag module with a knee airbag ( 50 ) according to one of the preceding claims, an inflator for filling the knee gas bag ( 50 ) and an outlet opening ( 72 ) housing ( 70 ) into which the knee airbag ( 50 ) is folded, the knee airbag ( 50 ) in the region of its front end ( 50a ) with the housing ( 70 ) connected is. Knee bag module according to claim 9, characterized in that the inflator in the form of a rod-shaped gas generator ( 40 ), from which gas generator bolts ( 42 ) through the support wall ( 15 ) and also for fastening the knee gas bag ( 50 ) on the housing ( 70 ) serve. Knee airbag module arrangement in a motor vehicle with a knee airbag module according to one of claims 9 or 10, wherein the housing ( 70 ) in a lower area of the instrument panel ( 80 ) or in a transition area between the instrument panel ( 80 ) and footwell ceiling ( 82 ) of the motor vehicle or a part of the footwell ceiling ( 82 ), wherein the outlet opening ( 72 ) of the housing ( 70 ) points substantially downwards or obliquely downwards and in the direction of the vehicle rear.

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