Airbag retaining device with a front wall and a recess

IS 2 256 121 T3

DESCRIPTION

Airbag restraint system with a front wall and a recess.

The invention relates to an airbag retention device, with an airbag module comprising a gas generator and an airbag with an airbag wall, comprising a front wall facing the occupant to be restrained, presenting a central section with a recess, in relation to the inflated state, with a cover of the module that when activating the airbag leaves an outlet orifice free, and with a retention device for the central section by means of which it is prevented, even in the inflated state of the airbag, a free movement, preferably any movement outside the airbag module, so that the recess is formed with an annular-shaped airbag chamber surrounding it.

Such an airbag restraint device is known from DE 197 49 914 A1. In this device, which has a so-called annular-shaped airbag, there is a so-called guide sleeve arranged in the center of the airbag module. The guide bushing is fixed on the rear face to the bottom of the airbag module, and on the front face, fixed to the cover of the module. Opening the module cover leaves a central section of the module cover standing. Also shown is a fixing device with a separate nut and a cap that hides the nut from the outside.

WO-A-97/34783 also shows an airbag retention device according to the species, in which a central multifunctional part is provided. The inner edge of the cover of an airbag module is arranged in an undercut of the multifunctional part in such a way that the cover only detaches from the multifunctional part when the airbag is activated, in order to allow the airbag to deploy .

DE-A-198 16 080 describes a multi-chamber airbag in the manner of a funnel airbag. This multi-chamber airbag has at least one free space in the shape of a funnel, starting from the outer contour of the inflated airbag that supports the impact, and extending to an area of ​​the module cover. The funnel-shaped clearance is formed because a part of the airbag wall at the bottom of the funnel is firmly attached to the module cover.

In DE-U-299 21 744, a central section of the module cover is made in such a way that the decorative or emblem pieces remain securely attached to the central section of the module cover, even in the in the event of high accelerations, and they cannot fly off as loose parts.

The invention creates an airbag retention device in which the fixing device is made more simply than in the state of the art, requires less construction space and the design of the module cover can be carried out with less complexity. This is achieved in an airbag retention device of the kind initially mentioned by the fact that the fixing device has a reinforcing element fixed to the module, integrated in the module cover, based on a plate from which it protrudes by at least one clamping piece protruding from the module cover, the reinforcing element being fixed in the gas generator by a component that surrounds the gas generator, so that when opening, The cover of the module remains firm in the area of ​​the central section and only the adjacent part is folded outwards to leave the outlet orifice free, the central section being trapped between the front wall of the gas generator or the component that surrounds the gas generator and module cover.

As mentioned, the reinforcing element is integrated into the module cover, for which it has been placed inside the foam or injection mold when foaming or injecting the module cover. In this way, the cover of the module remains firm in the area of ​​the central section when opening and only the adjoining part folds outwards to free the exit orifice. There are no problems at the junction between the clamping device and the module cover.

Clamping parts, such as threaded bolts, sheet metal lugs, rivet bolts or parts of a bayonet fastener, may protrude from the sheet metal insert, which protrude from the module cover and by means of which the clamping device is attached. in the module. Threaded bolts are screwed in, for example, sheet metal tabs are bent, rivet bolts are riveted in an orbital motion, and the bayonet lock is closed to lock the module cover with the center span permanently on the module.

According to one embodiment, the reinforcing element is fixed to a bowl-shaped diffuser overturned on the gas generator by a component that surrounds the gas generator, for example a stirrup. Here the central section is caught between the front front wall of the diffuser and the module cover. Other characteristics and advantages of the invention appear from the following description and the drawings that follow, to which reference is made. Figures show:

- Figure 1 a longitudinal section view through the airbag retention device according to the invention, which is integrated in a steering wheel of a vehicle,

- Figure 2 an enlarged view of the device represented in figure 1 in the area of ​​the gas generator, the module being closed,

- Figure 3 a view corresponding to figure 2 of a slightly modified embodiment, ^Y

- Figures 4a to 4c, views of three other embodiments of the device in the area of ​​the gas generator.

In FIG. 1 an airbag retention device with an airbag module is shown, housed in the steering wheel of the vehicle or in the dashboard on the passenger side, for the retention of the body and the back. The airbag module consists of an airbag 3, a gas generator 5, a module housing 7, in which the airbag 3 and the gas generator 5 are housed, and a module cover 9.

The airbag consists of an airbag wall of a woven material, with a front wall 11 which in the inflated state faces the occupant, and with which the occupant makes contact. A rear wall 12 is also provided, which may consist of a separate piece of tissue, which has an inlet hole 21 through which the genera3 is introduced.

The front wall has an annular front section 23 and a so-called central section 13, which is defined by a deep inlet 27. The section 23 is the one with which an occupant makes contact. zero, and serves for retention. In the installed state, the retainer is installed rotated 90 ° clockwise. The central section 13 is permanently fixed to the airbag module by means of a retention device, so that when deployed it cannot move outwards towards the occupant, like the rest of the airbag. For this reason, an annular airbag chamber 29 is produced, into which the gas is blown. The inlet 27 does not have to be open all of it in the inflated state but it can also be closed in sections, in that the opposite wall sections of the airbag are attached to each other. However, no gas enters the inlet 27 through the airbag chamber 29.

The central section 13 of the airbag wall is trapped between the module cover 19 (see Figure 2) and the upper front wall of the gas generator 5. A reinforcing element integrated in the module cover serves as a fixing device. coated with foam in the form of a sheet 41, which during the manufacture of the cover of the module 19 is covered with foam or coated by injecting it with, for example, a thermoplastic material. Clamping parts attached to the plate 41 protrude from the cover of the module 19, in the form of locking bolts or threaded bolts 43, which are fixed to the gas generator 5. The left bolt 43 'is a locking bolt and the bolt right 43 ”a threaded bolt.

The embodiment according to FIG. 3 essentially corresponds to that shown in FIG. 2, but around the gas generator 5 there is also arranged a bowl-shaped diffuser 51, which forms a component that surrounds the gas generator 5. and it is rigidly fixed to the module, and in which the threaded bolts 43 are screwed with the nuts 45. The central section 13 is therefore trapped between the cover of the module 19 and the central wall of the diffuser 51.

When the airbag is detached, it tears the cover of the module 19 opening it (see FIG. 1), so that an annular outlet hole 53 is produced, through which the airbag leaves the module. The retention device prevents the movement of the central section 13, so that the entrance 27 is formed.

The clamping piece can also be a sheet metal tab 53 (figure 4a) that protrudes and is bent at the free end, a rivet bolt 55 (figure 4b), riveted with an orbital machine, or a section of a bayonet lock 57 (figure 4c), in which the diffuser 51 has, for example, the corresponding opposite orifice.

The airbag, which is preferably deployed radially obliquely outward, exhibits good retention values.