WO2011009518A1

WO2011009518A1 - Airbag and method for producing same

Info

Publication number: WO2011009518A1
Application number: PCT/EP2010/003820
Authority: WO
Inventors: Brita Hirsch
Original assignee: Autoliv Development Ab
Priority date: 2009-07-23
Filing date: 2010-06-22
Publication date: 2011-01-27
Also published as: DE102009034557B4; DE102009034557A1

Abstract

An airbag with at least two side walls (21, 22) which are connected to each other at the edges and surround a gas compartment is described. The side walls are furthermore connected to each other in at least one connecting region (30), wherein the two side walls (21, 22) each have at least one opening (31, 32) in the connecting region (30), and the openings (31, 32) overlap at least in sections. In order to reliably prevent failure of the connecting regions using simple means, the connection of the two side walls (21, 22) in the connecting region (30) is produced by a single-piece connector (50) which is composed of a thermosetting or thermoplastic material and has two plate-like regions (51, 52) which are each located on the outsides of the side walls, and has a connecting section (54) which connects the two plate-like regions (51, 52) to each other and extends through the openings (31, 32).

Description

Airbag and method for its production

description

Technical field of the invention

The invention relates to an airbag according to the preamble of claim 1 and to a method for its production according to claim 9 and according to claim 11.

State of the art

So far, gas bags for motor vehicles are usually made of plastic fabric. As a rule, a gas bag consists of several blanks of the corresponding plastic fabric, which are sewn together. Here, it has also become known, in particular in curtain gas bags and side airbags, the two opposite side walls of the gas bag in the region of the protective chambers selectively sewn together so that the fully expanded gas bag is contoured and its thickness is limited. Such a side airbag is described for example in EP 0 814 001 A1.

From DE 40 38 910 A1 it has become known to produce a gas bag not made of tissue, but of plastic film. Plastic film has the advantage over plastic fabric that it is much easier and much cheaper to produce at higher gas tightness. A disadvantage of the use of films is that they can not be sutured in the rule, since the sewing on the one hand produces strong leaks in the film and also tends the film along the seams under load to tearing. If films are used for gas bags, they are therefore usually welded or glued.

The bonding or welding of foils to a gas bag basically works well, as long as the connection areas have a relatively large length. extend, in particular when the connection areas forms a peripheral peripheral connection between two blanks. In the case of rather punctiform connections, this type of connection often becomes problematic, since the force acting per unit area can be substantially greater here than in the case of a peripheral connection. However, such compounds, which are located within the protective area of the airbag, are often necessary, in particular in side airbags and curtain airbags, in order to give the airbag a desired profile. To solve this problem, the generic DE 10 2007 014 920 A1 proposes inter alia to provide an opening in each side wall in the connection area, to glue a fabric element to each side wall and to sew these two fabric elements together. The proposed type of connection works well in principle, but it has been found that the seam areas can form weak points, and that a relatively large effort is necessary to safely rule out a failure of the connection areas.

Subject of the invention

The present invention therefore has the task of developing a generic gas bag to the effect that a failure of the connection areas is reliably prevented by simple means. This object is achieved by an airbag with the features of claim 1.

According to the invention, the connection of the two side walls in the connecting region is produced by a one-piece connector consisting of a duroplastic or thermoplastic material, which connects two plate-shaped regions respectively located on the outer sides of the side walls and one the two plate-shaped regions and through the apertures having extending connecting portion. Such a connector eliminates seams that create potential weak points. The material of the connector forms a connection to the surrounding side walls during manufacture of the gas bag with suitable material combinations, which contributes to the mechanical stability and leads to a good gastightness.

It is a further object of the present invention to provide manufacturing processes for such a gas bag.

This object is achieved by a manufacturing method having the features of claim 9 and by a manufacturing method having the features of claim 11. The invention will now be explained in more detail using an exemplary embodiment with reference to the figures. Hereby show:

Brief Description of the Drawings Figure 1 A top view of a side airbag,

FIG. 2 shows a section along the line A-A from FIG. 1 in a highly schematic representation,

FIG. 3 shows that shown in FIG. 2 in a more realistic representation;

FIGS. 4a and 4b show a schematic representation of a first production method,

FIGS. 5a-5c show a schematic representation of a second production method,

FIG. 6 shows a representation of a variation of the second production method in a representation corresponding to FIG. 5b, FIG. 7 shows a second embodiment of a side gas bag in a representation corresponding to FIG

8 shows a section along the line BB in Figure 7. DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows a curtain airbag 10 in a side view. The airbag cover the curtain gas bag 10 consists essentially of two Seitenwan- fertilize 21 and 22, which are connected to each other via a peripheral connection 24 and enclose a gas space. From the upper edge of the curtain gas bag 10 extends a gas generator receptacle 12, from where the gas coming from the gas generator, not shown, gas is passed into the two protective chambers, namely the front protection chamber 14 and the rear protection chamber 16. The two side walls are each preferably made of a blank of a metal, composite or plastic film. As a material for a plastic film, for example, polyethylene (PE) or Pulyuret- han (PU) is suitable. The peripheral compound 24 may be a seam, a welded or glued line. However, it should be emphasized that the invention can also be applied to gas bags whose side walls are made of fabric, in particular plastic fabric.

In order to limit the thickness of the gas-filled curtain gas bag, the front protection chamber 12 has three connecting regions 30 in which the side walls 21, 22 are connected to one another. These connection areas are isolated from each other. The construction of such a connection region 30 will now be explained in more detail with reference to FIGS. 2 and 3, these showing a section along the line A-A from FIG. Here, the figure 2 is more schematic than the figure 3:

In the region of the connecting region 30, the two side walls 21, 22 each have an opening 31, 32, namely in the form of a round hole, these two openings 31, 32 are in the preferred embodiment shown congruent to each other. Furthermore, a one-piece connector 50 made of a duroplastic or thermoplastic material is arranged in the connection area. The plastic used must be malleable, weldable and chemically and mechanically resistant. Suitable materials are, for example, polyethylene (PE) or polyurethane (PU). The connector has two plate-shaped portions 51, 52 which rest on the outside on a side wall. Through the two openings 31, 32, a connecting portion 54 which connects the two plate-shaped areas together. Here, the diameter of the connecting portion 54 is smaller than the diameter of the plate-shaped portions 51, 52. Thus, the connector is held captive in the two openings.

As can be seen from the more realistic figure 3, the connecting portion 54, the openings 31, 32 completely fills and the plate-shaped areas are each a form-fitting manner on a side wall. As a result, the connector 50 seals the openings 31, 32 sufficiently, so that little or no gas is lost. Since there are no seams or the like in the connection area, the side walls are not selectively weakened, so that there are no "germ cells" for cracks when the side walls are under high tension during expansion of the gas bag or when immersing an occupant in the gas bag. As already mentioned, the connector is formed in one piece, so that it also has no construction-related weak point, at least when the side walls are made of plastic film, the result is an additional material connection between the connector and the side walls.

The thickness of the plate-shaped regions is preferably small, in particular between 0.1 mm and 1 mm, so that the plate-shaped regions are flexible and substantially follow the shape of the side walls both in the folded and in the expanded state.

FIGS. 4a and 4c schematically show a first possible production method. Here, the later connector is initially present as a one-piece blank 45. This blank 45 extends through the two openings 31, 32 and its end faces 45a, 45b are pressed together by two heated punches 60, 62 of a press until the two end areas are pressed to the plate-shaped areas, which are tapered by the opposite to the plate-shaped areas, extending through the apertures Connecting portion are connected together. The advantage of this production method is that the connector is integrated over the entire production process, so that a very good mechanical stability of the connector is easy to achieve.

Figures 5a to 5c show a second manufacturing method, which is often preferable. Here, the later connector is initially in the form of two plate-shaped blanks 51, 51 which in each case rest on a side wall 21, 22 and cover the opening 31, 32. Preferably, apertures 31, 32 and plate-shaped blanks 51, 52 are concentric with each other. By means of a press having two punches 60, 62, the two plate-shaped blanks are pressed together, at the same time heating at least one of the two blanks, whereby the connecting section is formed by plastic deformation and the two plate-shaped blanks, which then form the plate-shaped sections, join together be welded. The heating can be achieved by heating at least one of the two punches or by microwaves, for which purpose at least one of the two punches can have a microwave resonator. FIG. 6 shows a variant of the second production method just described in a representation corresponding to FIG. 5b. Here, a third plate-shaped blank 43 is provided, which is located in the region of the perforations 31, 32 and whose diameter is smaller than or equal to the diameters of the apertures 31, 32. When welded by the dies 60, 62 of the press, the third plate-shaped blank 43 is welded to the first and second plate-shaped blanks 40, 42. The advantage of this variant is that with simple means a slightly greater thickness of the connecting portion 54 can be achieved. Figures 7 and 8 show a second embodiment of the invention in a representation corresponding to Figures 1 and 2. Here, the connection area is not isolated in a protective chamber, but extends from the edge of the airbag, namely from the upper edge into a protective chamber - here the front protection chamber 14 - into. The overlying apertures in the side walls are not formed here as completely bounded holes, but as slots, each extending from the edge of the gas bag. Accordingly, the plate-shaped portions 51, 52 of the connector have no circular shape, but an elongated shape, namely the shape of elongated rectangles. The connecting portion 54 is also elongated.

The preferred application of the invention described are gas bags whose side walls are made of film. However, it is also applicable to gas bags, whose side walls are made of fabric.

LIST OF REFERENCE NUMBERS

10 curtain airbag

12 gas generator intake

14 front protection chamber

16 rear protection chamber

21 first side wall

22 second side wall

24 circumferential connection

30 connection area

31 first opening

32 second opening

40 first plate-shaped blank

42 second plate-shaped blank

43 third plate-shaped blank

45 one-piece blank

45a, b front side

50 connectors

51 first plate-shaped area

52 second plate-shaped area

54 connecting section

60 first stamp

62 second stamp

Claims

claims

1. Airbag with at least two edge side interconnected side walls (21, 22), which surround a gas space, wherein the side walls are further connected in at least one connection region (30), wherein the two side walls (21, 22) in the connection area ( 30) each have at least one opening (31, 32) and the openings (31, 32) overlap at least in sections,

characterized in that the connection of the two side walls (21, 22) in the connection region (30) is made by a one-piece connector (50) made of a thermosetting or thermoplastic material, which comprises two plate-shaped regions (11) located respectively on the outside of the side walls (Fig. 51, 52) and one the two plate-shaped portions (51, 52) interconnecting and through the openings (31, 32) extending connecting portion (54).

2. Airbag according to claim 1, characterized in that the Seitenwan- fertilize consist of foil.

3. Airbag according to claim 2, characterized in that the film consists of polyethylene (PE) or Pulyurethan (PU).

4. Airbag according to one of the preceding claims, characterized in that the connector consists of besipielsweise polyethylene (PE) or Pulyurethan (PU).

5. Airbag according to one of the preceding claims, characterized in that the openings of the two side walls in the connecting area are congruent to one another.

6. Airbag according to one of the preceding claims, characterized in that the openings (31, 32) are mutually bounded holes.

7. Airbag according to one of claims 1 to 5, characterized in that the openings (31, 32) are from the edge of the gas bag erstrek- kende slots.

8. Airbag according to one of the preceding claims, characterized in that each side wall in the connection area exactly one

Has opening.

9. A method for producing an airbag according to one of the preceding claims, comprising the following steps:

- introducing at least one opening (31, 32) into each side wall (21, 22) and arranging the two side walls (21, 22) such that the two openings (31, 32) at least overlap,

Arranging one element each (plate-shaped blanks 40, 42) of a thermosetting or thermoplastic material on the two outer sides of the side walls,

Welding of the two elements such that a through the openings (31, 32) extending connecting portion (54) is formed.

10. The method according to claim 9, characterized in that between the two elements, a third element (third plate-shaped blank 43) is arranged.

11. A method for producing an airbag according to one of claims 1 to 8, comprising the following steps:

Introducing at least one opening (31, 32) into each side wall (21, 22) and arranging the two side walls (21, 22) such that the two openings (31, 32) at least overlap,

Passing an element (integral blank 45) of a thermoset or thermoplastic material through the apertures, plastically deforming the element such that the two plate-shaped portions (51, 52) and the connecting portion (54) are formed.