Airbag module for a motor vehicle

The invention relates to an airbag module for a motor vehicle, comprising a gas sack, that can be inflated in order to protect a person by feeding gas into the gas sack, an openable reservoir for storing a coolant, wherein the reservoir comprises a first and a second portion, the second portion connected to the first portion, at least one outflow opening of the reservoir formed in the second portion, through which the coolant, for cooling the gas fed into the gas sack, can leave the reservoir, and a closure element for closing the outflow opening. According to the invention it is provided that the closure element divides the reservoir into the two portions, and that the coolant is arranged in the first portion, wherein the closure element seals the first portion of the reservoir with respect to the second portion of the reservoir. Further, the invention relates to a method for producing an airbag module.

BACKGROUND

The invention relates to an airbag module for a motor vehicle as well as to a method for producing an airbag module.

Such an airbag module for a motor vehicle comprises a gas sack that can be inflated in order to protect an occupant by feeding gas into the gas sack, an openable reservoir for receiving a coolant, wherein the coolant is divided into a first and a second portion connected to the first portion, at least one outflow opening of the reservoir arranged in the second portion, through which coolant for cooling gas fed into the gas sack can get into the gas sack, and a closure element for closing the outflow opening, so that no coolant can leave of the reservoir.

By cooling the gas fed into the gas sack or residing in the gas sack, the pressure inside the gas sack can be decreased in a defined manner at an arbitrary time (particularly independently from the time of activation of the gas generator). Hereby, the gas sack can be adapted to specific crash conditions (collision conditions) or to the occupant that shall be protected, particularly to his size and weight as well as to his position with respect to the gas sack (e.g. out-of-position, i.e., outside the normal position during driving).

SUMMARY

It is therefore desirable is to improve an airbag module of the kind mentioned in the beginning.

One disclosed embodiment relates to an airbag module for a motor vehicle, comprising a gas sack, that can be inflated in order to protect a person by feeding gas into the gas sack, an openable reservoir for storing a coolant, wherein the reservoir comprises a first and a second portion, the second portion connected to the first portion, at least one outflow opening of the reservoir formed in the second portion, through which the coolant, for cooling the gas fed into the gas sack, can leave the reservoir, and a closure element for closing the outflow opening, wherein the closure element divides the reservoir into the two portions, and in that the coolant is arranged in the first portion, wherein the closure element seals the first portion of the reservoir with respect to the second portion of the reservoir.

Another disclosed embodiment relates Method for producing an airbag module, comprising the steps of: Providing a tube extending longitudinally along an extension direction, that is divided into a first and a second portion along the extension direction, forming at least one outflow opening merely at the second portion, and inserting a closure element into the tube, so that the closure element divides the tube into the first and the second portion.

It is to be understood that the foregoing general description and the following detailed descriptions are exemplary and explanatory only, and are not restrictive of the invention as claimed.

DETAILED DESCRIPTION

According to one aspect of the invention, it is provided that the (particularly moveable) closure element divides, in an initial position, the reservoir into the two portions, and that the coolant is arranged in the first portion, wherein the closure element can be configured and provided to seal the first portion of the reservoir with respect to the second portion of the reservoir. In this manner, the closure element closes the at least one outflow opening although it is particularly spaced apart from said at least one outflow opening.

Or in other words, the (particularly moveable) closure element is arranged at the side of the reservoir facing the at least one outflow opening and can be moved along this (in)side past the outflow opening, in order to open the outflow opening for setting free the coolant.

Further, the problem underlying the invention is solved by a method for producing an airbag module comprising the steps of providing a tube extending longitudinally along an extension direction, that is divided into a first and a second portion along the extension direction, forming at least one outflow opening merely at the second portion, and inserting a closure element into the tube, so that the closure element divides the tube into the first and the second portion.

Advantageous embodiments of the invention are described in the sub claims as well as in the Figures and the corresponding explanations. Thereby, a longitudinally extending shape of the reservoir means that the reservoir comprises a larger extension along an extension direction than along directions running across the extension direction. Thereby, the reservoir can comprise a curvature along the extension direction, so that it is formed arcuated or annular, for instance.

Particularly, the closure element is configured and provided to be moved in the reservoir for opening the outflow opening, wherein the closure element is also arranged at least in sections inside the reservoir in the opened state of the outflow opening.

In order to connect the at least one outflow opening in a fluid-conductive manner to the cooling liquid stored in the first portion of the reservoir, the closure element is particularly designed to be moved along a movement direction out of an initial position, in which the closure element divides the reservoir into the first and the second portion, into a final position, namely in particular away from the first portion and past the at least one outflow opening, so that the coolant can get from the first portion into the second portion of the reservoir and can escape from there through the at least one outflow opening out of the reservoir. I.e., upon this movement, the closure element traverses particularly the second portion of the reservoir, and is thus, in its final position, arranged in the second portion of the reservoir.

Particularly, the reservoir comprises a wall extending longitudinally along the movement direction, which wall circulates across the movement direction and surrounds the coolant, wherein said wall can be particularly formed hollow-cylindrical at least in sections.

Particularly, the wall comprises an inside facing the closure element (and the coolant), that circulates correspondingly across the movement direction. The closure element rests on this inside and glides along the latter during its movement into the final position.

Furthermore, the reservoir particularly comprises a front face, which faces the closure element along the movement direction, wherein said front face forms a stop for the closure element that delimits the movement of the closure element into the final position. Thereby, the front face particularly comprises a central through-opening which the closure element engages in the final position.

Particularly, the at least one outflow opening is formed at said wall, so that the closure element can be lead past the at least one outflow opening in a simple manner. Due to the afore-mentioned arrangement of the at least one outflow opening, the coolant is discharged out of the reservoir across the movement direction.

In a variant of the invention, the closure element is formed spherical, wherein the wall or the inside of the wall comprises a corresponding circular contour in cross section.

In order to lock the closure element in its initial position, the closure element is particularly prevented from being moved into the second portion by means of at least one bead circulating at the reservoir in the form of a protrusion circulating at the inside. For this, said bead is arranged along the movement direction between the closure element being in the initial position and the at least one outflow opening. The bead is a constriction of the reservoir, past which the closure element can only be moved, in case a certain, pre-definable minimal force acts on the closure element along the movement direction. Particularly, two such beads are provided, which are arranged on both sides of the closure element being in the initial position.

In order to ensure sealing of the first portion of the reservoir with respect to the second portion and in order that the closure element can be moved past the one bead, the closure element is designed (elastically) deformable in a variant of the invention. Alternatively, it is provided in a further variant of the invention, that the reservoir or the wall is designed (particularly elastically) deformable, whereas the closure element is particularly designed less deformable or rigid.

For moving the closure element out of the initial position into the final position, a movement generating device is particularly provided that is designed to act on the coolant with a pressure, so that the coolant presses the closure element out of the initial position into the final position. Further, the movement generating device can be configured and provided to provide a pressure in the first portion of the reservoir, so that the reservoir is widened in cross section. Hereby, locking of the closure element in the initial position can be released in case of a rigid closure element and the closure element can be moved into its final position. Particularly, the movement generating device is formed by a gas generator that is particularly clamped with a free end of the first portion of the reservoir.

Particularly, the reservoir is designed to extend longitudinally, particularly along the movement direction, wherein the reservoir is particularly designed tubular. In this connection, the reservoir can be indeed designed to have a curvature. The movement direction then follows said curvature or curvatures of the reservoir. In this way, the reservoir can be designed for instance to be ring-shaped in an open manner, particularly in case of a reservoir that is arranged or formed at a retaining element (e.g. diffuser) for a gas sack. Particularly, in case of a longitudinally extending reservoir, there is the possibility to pass the latter out of a module housing of the airbag module, in order to e.g. provide for an easily accessible interface between the movement generating device and an electronics on the vehicle side.

Particularly, the second portion of the reservoir is arranged such that coolant escaping out of the at least one outflow opening can flow through an inflow opening of the gas sack into the gas sack, in particular the second portion or even the whole reservoir can be arranged in an interior space of the gas sack defined by the gas sack.

In a variant of the invention it is provided that the reservoir is arranged at a retaining element of the airbag module that serves for fastening the gas sack to the airbag module, wherein the reservoir is particularly integrated into the retaining element, namely particularly by releasably (e.g. latching or screw connection) or non-releasably (e.g. welded connection) fixing it as a separate part to the retaining element or to a part of the retaining element. In an embodiment, the retaining element is designed as an annular circulating clamping ring that is configured and provided for clamping the gas sack to a part of the airbag module (e.g. to a module housing or to a gas generator). In another embodiment, said retaining element can also be formed by a diffuser for distributing gas set free by a gas generator. Such a diffuser particularly comprises a circulating flange to which the reservoir is fastened particularly as a separate part. The reservoir can also be an integral part that is formed in one piece with the flange or the retaining element.

Particularly, the reservoir can comprise a curvature, so that the reservoir protrudes, with a portion that comprises the movement generating device in particular, out of the gas sack, wherein said portion can run across the flange in particular. In this connection, the movement generating device can protrude at least in sections (or completely) out of the gas sack.

In a further embodiment of the invention, a further additional closure means is provided that can be moved out of an initial position, in which the further closure means is arranged such that the coolant is enclosed along the movement direction between the two closure means, into a final position, wherein the further closure means, upon moving into its final position, takes along the coolant and the one closure means, so that particularly on the one hand the one closure means is moved past the outflow openings (movement of the one closure means out of the initial position of the one closure means into the final position of the one closure means) and, on the other hand, the coolant can be set free particularly through the outflow openings into the interior space of the gas sack.

The further closure means can be formed like the one closure means and can be particularly locked in the same manner.

In this connection, the movement generating device is particularly configured and provided to act on the coolant with a pressure via the further closure means, so that the further closure means presses the coolant out of the reservoir and thereby carries the one closure means out of its initial position into its final position.

Furthermore, the problem according to the invention is solved by a method for producing an airbag module, particularly according to one of the claims1to13. The problem according to the invention comprises the steps of: Providing a hollow body or tube extending longitudinally along an extension direction that is divided along the extension direction into a first and a second portion, forming at least one outflow opening merely at the second portion, and inserting a closure element into the hollow body or tube such that the closure element divides in this initial position the tube into the first and the second portion.

Particularly, as a closure element, an (elastically) deformable element (e.g. in the form of a sphere) is inserted into the tube, which closure element seals the first portion with respect to the second portion, so that coolant stored in the first portion cannot escape out of the at least one outflow opening formed at the second portion, or a rigid element is provided as a closure element and the reservoir is formed deformable or elastically deformable. Thus, upon acting on the coolant with a pressure, either the contact pressure of the elastically deformable closure element on the wall of the reservoir is surmounted, so that it can be moved out of the initial position into the final position, or the reservoir is widened in cross section due to the provided pressure, so that a rigid (less deformable) closure element can be pressed out of the initial position into the final position.

For fixing the movement generating device, particularly a free end of the first portion is widened in cross section along a cross section plane running across the extension direction of the tube.

In order to further avoid that the closure element can be pressed out of the tube (the second portion) along the extension direction of the tube (movement direction), a free end of the second portion, that faces the free end of the first portion along the extension direction, is narrowed in cross section.

The first portion of the tube or reservoir particularly serves as a receptacle for the coolant and is therefore filled through an opening of the first section, which opening is delimited by the free end of the first portion, with said coolant.

In an embodiment of the method according to the invention it is provided that a further closure means is arranged in the first section, particularly through an opening of the first portion, which opening is delimited by the free end of the first portion, wherein the two closure means enclose the coolant along the movement direction. Thus, the further closure means serves as a piston that can be acted on with a pressure, which piston correspondingly presses the coolant out of the reservoir and thereby presses the one closure means being opposite along the movement direction out of its initial position into its final position in a way (via the cooling liquid as a force mediator), that the one closure means is moved past the outflow openings and therefore frees said outflow openings for exhausting the coolant.

The said movement generating device is particularly arranged through the opening of the first portion in the first portion of the tube (and thereafter particularly fixed in the tube), wherein particularly the free end of the first portion, which free end delimits said opening of the first portion, is clamped with the movement generating device in order to fasten the movement generating device in the reservoir, so that said free end of the first portion of the reservoir tightly encompasses and particularly engages behind the movement generating device, so that the movement generating device cannot be pulled out of the reservoir just like that opposite to the movement direction of the closure element.

FIG. 1shows a schematical cross sectional view of a reservoir2of an airbag module according to the invention, which reservoir2serves for storing a coolant3that can be set free through a plurality of outflow openings6, that are formed at a longitudinally extending circulating wall20of the reservoir2, into an interior space I surrounded by a gas sack1, in order to cool gas residing therein that serves for inflating the gas sack1. Hereby, the pressure inside the gas sack1is decreased according to well-established laws of physics. In this connection, said outflow openings6can be suitably arranged with respect to an inflow opening1aof the gas sack1or directly in the interior space I of the gas sack1. Further, there is the possibility to arrange the whole reservoir2in said interior space I of the gas sack1.

A movement generating device9in the form of a gas generator is arranged in the reservoir2, which movement generating device9is designed to act on the coolant3residing in the reservoir2with a pressure, so that this is set free through said outflow openings6into the interior space I of the gas sack1. Thereby, the movement generating device9can be activated at an arbitrary time, particularly independently of the time of activation of the gas generator by means of which the gas needed to inflate the gas sack1is provided. Particularly, the coolant3stored in the reservoir2(e.g. cooling liquid, particularly water) can be set free into the interior space I of the gas sack1and brought into contact with the gas during or after inflation of the gas sack1.

Particularly, a control electronics for controlling or activating the movement generating device9is provided, wherein said control electronics calculates the time of activation of the movement generating device9(or the time of setting free the coolant3) depending on at least one parameter that can be detected by at least one sensor that can be arranged in or at a motor vehicle. Particularly, such a parameter can be a deceleration of the motor vehicle, the size of the occupant to be protected or his mass, as well as his position with respect to the gas sack. Hereby, the gas sack1can be particularly adapted to a so-called “out-of-position”-case in which the occupant is positioned too close to the gas sack, particularly with his head, and therefore, a corresponding risk of injury exists.

In order that the coolant3cannot escape through the outflow openings6of the reservoir2out of the reservoir2before the activation of the movement generating device9, a closure element7is provided that is arranged spaced apart with respect to the outflow openings6in the reservoir2and thereby divides the reservoir2in a first portion4and a second portion5, such that coolant3residing in the first portion4cannot get past the closure element7into the second portion5at which the outflow openings6are formed. The closure element7is thus arranged along the reservoir2between the coolant3and the outflow openings6(initial position). In order to assure the sealing between the first portion4and the second portion5, the outer diameter of the closure element7is provided with an oversize compared to the inner diameter of the wall20. This means, that the closure element7has to be elastically deformed for housing in the reservoir2, and thus, in the mounted state, butts against the inside21of the wall20with a certain contact pressure. Thereby, the contact pressure is determined by the amount of the oversize. The closure element7can be moved out of the initial position along a movement direction E that runs along the extension direction of the reservoir2by acting on the coolant3that is stored in the first portion1of the reservoir2with a pressure by means of the movement generating device9.

For this, the movement generating device9is arranged at a free end10of the first portion4of the reservoir2, which free end10faces the closure element7along the movement direction E. If the coolant3stored in the first portion4of the reservoir2is now acted on with a pressure by means of the movement generating device9, said closure element7is also acted on with said pressure and therefore moves along the movement direction E away from the movement generating device9towards the second portion5of the reservoir2, namely such that it glides in the reservoir2past the outflow openings6and thereby traverses the second portion5of the reservoir2. A front face22of the reservoir2at a free end16of the second portion5of the reservoir2, which front face22faces the free end10, thereby forms a stop for the closure element7that delimits the movement of the closure element7along the movement direction into the final position. As soon as the closure element7hits said front face22of the reservoir2, it resides in its final position in which it has been completely moved past the outflow openings6along the movement direction E. Now, the coolant3can get out of the first portion4, due to the pressure acting on the coolant3, into the second portion5of the reservoir2and can be set free from there through the outflow openings6into the interior space I of the gas sack1. The closure element7is thus always arranged inside the reservoir2and does not leave the latter. However, a through-opening23can be provided at the front face22, into which the closure element7can project into its final position. This through-opening can be provided for reasons of manufacturing (see below).

For locking the closure element7in its initial position such that it cannot be moved unintendedly out of this initial position, two beads8circulating across the movement direction E can be provided in addition to the afore-described fixation by means of the elastic deformation of the closure element7, which beads8protrude from an inside21of the wall20facing the closure element7into the reservoir2and are arranged along the movement direction E on both sides of the closure element7, so that on both sides of the closure element7the cross section of the reservoir2is narrowed in a plane being oriented perpendicular to the movement direction E and therefore the closure element7is held in the initial position between these two beads8along the movement direction E. Thus, a certain pre-definable minimum force has to act on the closure element7, in order to move it out of this initial position along the movement direction E into its final position. In this connection, the closure element7can be designed deformable or elastically deformable or the closure element7can be a rigid closure element, e.g. a steel sphere, wherein in such a case the reservoir2or the wall20can itself be designed deformable or elastically deformable, so that the closure element7can be forced past the bead8arranged between the closure element7and the outflow openings6along the movement direction E, when the movement generating device9acts on the coolant3with a pressure, in order to displace the closure element7along the movement direction E into its final position (cf.FIG. 3).

FIG. 4shows on the basis of a schematical cross sectional view a modification of the reservoir2shown inFIG. 1, in case of which, in contrast toFIG. 1, the closure element7is not spherical, but designed in the form of a cylinder, particularly in the form of a circular cylinder.

FIG. 5shows in a schematical cross sectional view a modification of the reservoir2shown inFIG. 1, in case of which, in contrast toFIG. 1, the closure element7is not spherical, but designed in the form of a flattened sphere, particularly in the form of an ellipsoid.

FIG. 6shows a diffuser13of an airbag module according to the invention with a part of a gas sack1in an exploded view, wherein said diffuser13is formed cap-shaped and comprises an annularly circulating flange12for fixing to a module housing of an airbag module, from which flange12bolts120protrude that are configured and provided to engage through-openings of a module housing or another part of an airbag module for fastening the diffuser13to said airbag module. Particularly, said bolts120protrude counter to a main unfolding direction H of the gas sack1, along which the gas sack1unfolds towards an occupant to be protected upon inflation.

Thereby, the flange12rests from the interior space I of the gas sack1with a lower side12afacing the gas sack on a boundary region1bdelimiting the inflow opening1aof the gas sack1, so that said boundary region1b, upon fastening the diffuser13to the airbag module, particularly to a module housing of the airbag module, is clamped between the flange12and said part of the airbag module. The boundary region1bof the inflow opening1aof the gas sack thereby comprises through-openings120athat are each engaged by a bolt120.

A reservoir2is arranged at the flange12in the manner ofFIG. 1, which reservoir2annularly circulates in an open manner at an upper side12bof the flange12of the diffuser13facing away from the boundary region1b, so that the movement generating device9provided at the free end10of the first portion4of the reservoir2is arranged adjacent to the free end16of the second portion5of the reservoir2, at which free end16said front face22having an optional through opening23is formed. The outflow openings6of the reservoir2are thereby arranged at the wall20of the reservoir2in a way, that they face away from the boundary region1bof the inflow opening1aof the gas sack1or face the interior space I of the gas sack1, so that the coolant3set free out of the reservoir2through the outflow openings6can be set free into the interior space I of the gas sack1on the shortest route. Particularly, the reservoir2according toFIG. 6, as a separate part, is releasably fixed (e.g. latching or screw connection) or non-releasably (e.g. rivet or welded connection) to the flange12.

Of course, it is also possible to form the reservoir2in one piece with said flange12, wherein particularly the wall20or the reservoir2can form said flange12by itself. In this case, the bolts120are fixed directly to the wall20or the reservoir2.

FIG. 7shows on the basis of a schematical, perspective view a modification of the reservoir2shown inFIG. 6, wherein said reservoir2, in contrast toFIG. 6, is not formed at a flange12of a diffuser13, but at an annularly circulating clamping element14for the gas sack1, from which said bolts120protrude counter to said main unfolding direction H for fixing the clamping element to an airbag module, particularly to an airbag module housing. Thereby, the clamping element14serves for clamping said boundary region1bof the gas sack1that delimits and circulates the inflow opening1aof the gas sack1to a part of the airbag module, particularly to an airbag module housing. In this connection, the clamping element14presses, like the flange12according toFIG. 6before, from the interior space I of the gas sack1against the boundary region1bof the inflow opening1a, namely against an inside of said boundary region1bfacing the interior space I.

Particularly, the reservoir2is fixed to the circulating clamping element14as a separate part and annularly circulates in an open manner along the clamping element14, so that the free end10with the movement generating device9fixed thereto is arranged adjacent to the front face22or the free end16of the second portion5of the reservoir2. Regarding possible kinds of connection between the reservoir2and the clamping element14, it is referred to the explanations with respect toFIG. 6.

Further, there is also the possibility to form the reservoir2in one piece with the circulating clamping element14. According toFIG. 6, the reservoir2can form said clamping element14by itself, wherein in this case the bolts120are directly fixed to a lower side of the reservoir2facing the boundary region1bof the gas sack1.

The two variants according toFIG. 6andFIG. 7are particularly given by a diffuser13or a clamping element14for a driver airbag module. Provided that the reservoir2is releasably fastened to the flange12of the diffuser or to the circulating clamping element (clamping ring)14, there exists, with advantage, the possibility, to upgrade a usual driver airbag module with such a reservoir2of an airbag module according to the invention.

FIG. 8shows in connection withFIG. 9a schematical, perspective view of an airbag module in the form of a co-driver airbag module having a rectangular module housing11that forms a receptacle A for a folded (not inflated) gas sack1(not shown inFIG. 8), wherein said module housing11comprises a flat bottom15that serves for clamping a boundary region1bdelimiting an inflow opening1aof the gas sack1. This can take place by means of a clamping element mentioned in connection with the description ofFIG. 7that was adapted correspondingly. From the bottom15, a wall11aprotrudes along a main unfolding direction H, along which the gas sack arranged in the receptacle A unfolds towards the occupant or co-driver to be protected, which wall11acirculates across the main unfolding direction H and has a boundary region11acoming off therefrom across the main unfolding direction H, via which boundary region1bthe module housing11can be fixed to a motor vehicle part. For this, through-openings11care provided at said boundary region11bof the module housing11that can be engaged by suitable fastening means, for example screws. The mentioned motor vehicle part can be an instrument panel of a motor vehicle in particular.

The bottom15of the module housing11comprises a trough-shaped indentation20in which a gas generator300can be arranged that serves for inflating the gas sack1that is to be arranged in the receptacle A. On both sides of the trough-shaped indentation20, barrel-shaped protrusions310are arranged that partly surround the gas generator300in the main unfolding direction H, i.e., circulate across the main unfolding direction H at least in sections, and are overlapped by a part of the boundary region1bdelimiting the inflow opening1aof the gas sack1. For cooling the gases fed into this gas sack1acoolant3stored in a reservoir2is provided, wherein said reservoir2comprises according to the manner ofFIG. 1a first portion4and a second portion5, wherein said coolant3is provided in the first portion4and the at least one outflow opening6for exhausting the coolant3in the second portion5of the reservoir2. Said two portions4,5are thereby sealingly separated from each other by a closure element7according to the manner ofFIG. 1, wherein said closure element7can be moved in the afore-described manner by means of a movement generating device9that is provided at a free end10of the first portion4of the reservoir2along a movement direction E past the outflow openings6into a final position in which the closure element7is arranged according toFIG. 3at a free end16of the second portion5or at a front face22of the reservoir2formed at this position.

According toFIG. 9, this reservoir2comprises a curvature, so that the second portion5, at which said outflow openings6are formed, runs essentially across the first portion4of the reservoir2in which the coolant3is stored. Thereby, the second portion5protrudes according toFIG. 8with its outflow openings6through a through-opening15aprovided in a barrel-shaped protrusion310into the receptacle A delimited by the module housing11in a way, that the outflow openings6face along the main unfolding direction H an inflow opening of the gas sack that is to be arranged in the receptacle A. Thus, coolant3set free through the outflow openings6can be set free directly into an interior space of said gas sack as described above.

For electrically contacting the movement generating device9, also the free end10of the first portion4of the reservoir2, to which free end10the movement generating device9is particularly fixed, protrudes out of the module housing11.

FIG. 10shows in connection with theFIGS. 11 to 17on the basis of schematical cross sectional views the production of a reservoir2according to the manner ofFIG. 1. The production of the other variants of the reservoir2proceeds in an analogous fashion.

First, as a base piece of the reservoir2, a tube2alongitudinally extending along the later movement direction E having a certain length and curvature (optional) is provided, wherein said tube2acomprises a wall20longitudinally extending along the later movement direction E that circulates across said movement direction E (thus, the movement direction E coincides with the extension direction of the tube2aor of the reservoir2). Depending on the geometry of the closure element7, this wall20comprises in a cross sectional plane running across the movement direction E corresponding dimensions. Said tube2acomprises two free ends10,16that face each other along the movement direction E and delimit an opening17a,18b, respectively.

After providing said tube2a, a plurality of outflow openings6is formed according toFIG. 11at a second portion5of the tube2athat comprises the free end16of the tube2a. These can be stamped into the tube2a, wherefore a counter bearing element200is form-fittedly inserted (counter to the movement direction E) into the tube2athrough the opening17bformed at the free end16of the second portion5, so that the tube2adoes not experience an indentation, when the outflow openings6are stamped into the second portion5of the tube2a.

Hereafter, a widening is formed according toFIG. 12at a further free end10of a first portion4of the tube2aconnected to the second portion5, which free end10faces the outflow openings6or the free end16of the second portion5of the tube2aalong the movement direction E, so that said free end10obtains a step50that circulates across the movement direction E and thereby extends flatly annularly along a plane running across the movement direction E.

Then, according toFIG. 13, a closure element7in the form of a sphere (other shapes are also possible) is brought (pressed-in) into the tube2athrough the opening17bof the free end16of the second portion5of the tube2a, namely in an initial position in which the closure element7sealingly separates the second portion5from the first portion4of the tube2a. Hereafter, according toFIG. 14, the free end16of the second portion5is narrowed, namely by means of folding (flanging) said free end.

Afterwards, according toFIG. 15, coolant3is filled into the reservoir2through the opening17aof the free end10of the first portion4of the reservoir2, and hereafter, according toFIG. 16, a movement generating device9is inserted along the later movement direction E, which comprises a broadened end region that rests along the movement direction E via a sealing100annularly circulating along the step50on said step50. In this connection, said sealing100comprises a side via which the sealing100butts against the circulating step50as well as a side facing away from this circulating side via which the sealing100butts against the broadened region of the movement generating device9. In order to fix the movement generating device9in the free end10of the first portion4of the reservoir2and thereby, at the same time, pretension the movement generating device9against the sealing100, the free end10is clamped with the broadened region of the movement generating device9(by means of flanging/crimping), so that a circulating boundary of the free end10engages behind the broadened region of the movement generating device9, so that the movement generating device9is held counter to and along the movement direction E of the closure element7in the free end10of the first portion4of the reservoir (tube)2a(cf.FIG. 17).

FIG. 18shows on the basis of a schematical cross sectional view a modification of the reservoir2of an airbag module according to the invention shown inFIG. 1, in case of which, in contrast toFIG. 1, a further closure means77in the form of a sphere is provided (the further closure means77can also have one of the other afore-described shapes and properties).

The further closure means77is thereby arranged such in the first portion4of the reservoir2, that the coolant3is enclosed along the movement direction E between the two closure means7,77.

Particularly, the further closure means77is thus arranged along the movement direction E between the movement generating device9and the coolant3and therefore functions as a piston for pressing out the coolant3out of the reservoir2.

Namely, in case the movement generating device9acts on the further closure means77with a pressure, the further closure means77is pressed towards the outflow openings6out of its initial position, wherein it takes along the coolant3, which on his part takes along the one closure means7and moves it past the outflow openings6, so that it butts against the front face22of the reservoir2. Now, the pressurized further closure means77presses the coolant through the outflow openings6out of the reservoir2.

The closure means77arranged adjacent the free end10of the first portion4also comprises, besides sealing upon activation of the cooling device2,3,9,7,77, the function of a piston that presses the coolant3out of the outflow openings6of the reservoir2. The additional closure element77thus separates upon ignition of the movement generating device9(gas generator) the arising gases from the coolant3that can directly develop its cooling effect in this way, which becomes noticeable in significantly shorter times until a certain pressure decrease is noticeable in the gas sack. Without this further closure element77a mixing of gases of the movement generating device9with the coolant3delaying the pressure decrease occurs.

Finally,FIG. 19shows a modification of the airbag module shown inFIG. 6, wherein in contrast toFIG. 6the reservoir2comprises a curvature (bending) in the first portion4, so that a portion4′ of the reservoir2, that comprises the free end10of the first portion4of the reservoir2and the movement generating device9, protrudes out of the gas sack1. The curvature is designed such that the portion4′ of the reservoir2runs parallel to the bolts120or perpendicular to the lower side12aof the flange12. Or in other words, said portion4′ of the reservoir2extends along the main unfolding direction H.

The reservoir2, in contrast toFIG. 6, is designed according toFIG. 18, i.e., the coolant3is, as described above, enclosed between the closure means7,77. In contrast toFIG. 18, the reservoir2is bent according toFIG. 19and extends (circulates) along the flange12, wherein the second portion5extends along the flange12. Also the part of the first portion4that contains the coolant3—which is caged between the closure elements7,77—extends along the flange12. Hereof, said portion4′ comes off that protrudes out of the gas sack1.

The gas sack1is not shown inFIG. 19. In this respect it is referred toFIG. 6.