ASSEMBLY CONSISTING OF A DIFFUSER AND A GAS GENERATOR, GAS BAG MODULE AND METHOD FOR ASSEMBLING AN ASSEMBLY

Description

[0001] The invention relates to an assembly comprising an elongated gas generator and a clamp-shaped diffuser that encloses an outflow area of ​​the gas generator. Furthermore, the invention relates to a gas bag module comprising such an assembly and a method for assembling such an assembly.

[0002] In elongated gas generators, also known as tubular gas generators, the outlet area is typically formed by a multitude of outlet openings distributed around the circumference of the gas generator's outer casing. The outlet openings are often located in a filter housing at one axial end of the gas generator. The gas therefore flows out of the gas generator in a radial direction. To keep the gas generator thrust-neutral during activation, the outlet openings are often evenly distributed around the circumference.

[0003] In many airbag modules, the gas generator is positioned so that its discharge area is located within the inflatable volume of the airbag. This design is found, for example, in curtain-type side airbags or in side airbags installed in the backrest of a vehicle seat.

[0004] The airbag must be protected from the gas flow escaping from the gas generator. For this purpose, a special fabric layer is known, for example, to surround the gas generator's outlet area circumferentially, which both protects the airbag fabric and redirects the gas flow in the axial direction. An axially directed outlet has the advantage of allowing the gas to be better distributed within the airbag.

[0005] It is also known to provide a so-called gas lance, which has a pipe section open at both ends as its main component and is attached axially to a gas generator to transfer the escaping gas over a distance of several decimetres to a gas bag located remotely from the gas generator. While this allows a directed gas flow into the gas bag, it is not possible to position the gas generator's outflow area directly within the gas bag, which inevitably increases the dimensions of the gas bag module.

[0006] From the document DE 11 2009 004 386 B4 an assembly consisting of a gas generator and a diffuser is known, which divides the gas flow exiting the gas generator.

[0007] The object of the invention is to create a possibility to guide the gas flowing out of the gas generator into the gas bag, with a small design, good adaptability to different geometries and low manufacturing costs.

[0008] This object is achieved with an assembly having the features of claim 1. The assembly according to the invention consists of an elongated gas generator having an outer housing with outflow openings distributed around the circumference, which define an outflow region and an outflow direction, and of a clamp-shaped diffuser enclosing the outflow region, wherein the diffuser has a central receiving opening into which the outer housing of the gas generator projects, so that the diffuser circumferentially encloses an axial section of the outer housing which comprises the outflow region. On the inner side of the diffuser delimiting the receiving opening, at least one contact surface and at least one gas guide surface are provided, wherein the contact surface bears directly against the outer housing and the gas guide surface is radially spaced from the outer housing to form at least two collection chambers into which gas flowing out of the outflow region flows.The collection chambers each open into at least one outlet opening through which gas leaves the diffuser in an outlet direction transverse to the outflow direction from the gas generator.

[0009] The diffuser simultaneously redirects the gas flowing out of the gas generator in one or more desired directions and protects the surrounding area from direct contact with the escaping gas. Because the diffuser directly surrounds the gas generator's outlet area, it can be manufactured with compact dimensions.

[0010] The diffuser can be easily designed so that essentially all of the gas flowing out of the gas generator flows into at least two collection chambers.

[0011] The diffuser is preferably a formed sheet metal ring. It can be realized, for example, as a stamped and bent part. This manufacturing process allows the diffuser to be easily designed for various gas generator and gas bag geometries and, for example, to be adapted to an axial length of the gas generator's outlet area or a gas generator's diameter, as well as to specify the desired number, location, position, and / or direction of the outlet openings. Alternatively, the diffuser can be made from a tubular element, in particular a steel tube.

[0012] In order to reduce the required installation space as much as possible, the diffuser should be designed so short in the axial direction that it protrudes only slightly beyond the axial end of the gas generator and thus the axial length of the assembly essentially corresponds to the axial length of the gas generator.

[0013] The diffuser can extend completely over the outflow area of ​​the gas generator in the axial direction, so that all of the outflowing gas first enters the diffuser.

[0014] In this application, the term "axial length" or "axial direction" is always used with reference to the longitudinal axis of the gas generator.

[0015] The outlet direction from the diffuser preferably runs axially relative to the longitudinal axis of the gas generator, i.e., parallel to its longitudinal axis. The gas flowing out of the gas generator's outlet area is deflected approximately 90° transversely to its outlet direction.

[0016] According to the invention, at least two outlet openings are provided, which are directed in opposite directions. In this case, the gas exits the diffuser in two opposite directions, each pointing along the axial direction. This enables faster distribution of the gas in the gas bag and can keep the gas generator essentially or even completely thrust-neutral.

[0017] The volume of the collection chamber and the area of ​​the outlet openings can be selected in such a way that the excess pressure in the diffuser is essentially not too high compared to the gas escaping from the outlet area.

[0018] The two outlet openings can be positioned opposite each other along the axial direction. The area of ​​both outlet openings can be the same or different. In general, the choice of the number, area, and position of the outlet openings is at the discretion of the expert.

[0019] Depending on the geometry of the gas bag to be filled, two oppositely directed outlet openings can also be provided, which are spaced apart from each other in the circumferential direction.

[0020] The outlet openings can be easily implemented in the diffuser by locating the gas guide surface radially further outward adjacent to the outlet openings than in the at least one associated collection chamber, which is located away from the outlet openings. Viewed differently, the collection chamber expands radially at the transition to the outlet opening, so that, particularly in a radial section, the outlet opening occupies a larger area than the collection chamber, and the gas can flow out of the diffuser without increased resistance.

[0021] In the area of ​​the outlet openings, for example, both the gas guide surface and the contact surface can be spaced radially from the outer circumference of the gas generator, so that an opening is formed which is continuous in the axial direction through the entire diffuser and is open at both ends, the two open ends defining the outlet openings.

[0022] In general, the contact surface(s) can define the collection chamber(s) in the axial and / or circumferential directions, whereby a suitable choice of the contact surface configuration allows for any geometry of one or more collection chambers. Additional guide elements for the escaping gas are not required. The contact surfaces can generally be completely spaced from each other or can merge into one another in sections.

[0023] In one possible embodiment, the diffuser is designed such that at least one collecting chamber is provided, which is not continuous in the circumferential direction and opens into at least one outlet opening at both of its circumferential ends. The collecting chamber can, for example, extend over an angular section of approximately 200° to 350°, and in particular from 220° to 270°.

[0024] Two or more collecting chambers separated from each other in the circumferential direction can be provided, each of which opens into at least one outlet opening. It is also conceivable for one outlet opening to be assigned to several collecting chambers.

[0025] In another possible embodiment, a collection chamber is provided that opens into an outlet opening at one axial end. In this case, the gas does not have to be guided along the circumferential direction, but can be deflected directly in the axial direction by the gas guide surface.

[0026] The outlet opening can be formed, for example, by a radial gap between the outer casing and the inside of the diffuser, which simplifies diffuser manufacturing. In this design, the radial expansion of the diffuser can be limited to the radial distance between the gas guide surface and the outer wall of the gas generator. In particular, the outlet opening can be formed by an axially open slot between the inside of the gas guide surface and the outer contour of the gas generator.

[0027] The two embodiments just described can of course also be combined so that the diffuser has at least one collecting chamber opening into an outlet opening in the circumferential direction and at least one collecting chamber opening into an outlet opening in the axial direction.

[0028] The at least one contact surface can be used to divide the gas flow exiting the generator into at least two partial flows. The shape of the contact surface can easily determine the number of outlet openings of the gas generator located below the gas guide surface. These outlet openings, in turn, determine the proportion of the total filling gas that enters the respective partial flow and is guided via the respective gas guide surface to one of the outlet openings. Preferably, the individual partial flows are directed into different collection chambers and from there to different outlet openings.

[0029] In one possible embodiment, the contact surface runs only in the circumferential direction around the outer housing.

[0030] In another possible embodiment, the contact surface runs helically around the outer housing.

[0031] A particularly simple form of a contact surface, with which partial gas flows with different gas quantities can be generated, provides that, in a contact surface running around the entire circumference of the gas generator, two first sections running only in the circumferential direction and two second sections running obliquely to the circumferential direction and to the axial direction are provided, with the second sections connecting the first sections. Preferably, the contact surface separates two axially separated collection chambers, each with at least one separate outlet opening. The choice of the length and inclination of the second sections running obliquely to the axial direction determines the number of outlet openings that supply the respective partial gas flow with gas.

[0032] In a further embodiment, a plurality of outlet openings can be arranged distributed over the circumference. Preferably, the outlet openings are separated by separating webs, which at least partially form the contact surfaces of the diffuser that delimit the collection chamber in the axial direction. Such outlet openings, distributed over the circumference and interrupting the contact surface distributed over the circumference, are arranged in particular on the front side of the diffuser and thus, in the assembled state of the diffuser, toward a longitudinal end of the gas generator.

[0033] The diffuser of the assembly may comprise at least one locking element for attachment and fastening to the gas generator. Preferably, in such an embodiment, the diffuser comprises two or more locking elements.

[0034] The locking element is designed to engage a groove to secure and secure the diffuser to the gas generator. This locking action secures the diffuser to the gas generator via a positive connection. The locking elements allow the diffuser to be easily attached to the gas generator. However, it is also possible to additionally attach the diffuser to the gas generator by pressing or welding.

[0035] In one embodiment, the locking element is arranged adjacent to a contact surface of the diffuser. Such a diffuser with one or more locking elements can preferably be made of spring steel, in particular an intermediate-tempered spring steel.

[0036] Normally, the outflow area is provided at one axial end of the gas generator, so that the diffuser is also arranged at one axial end of the gas generator.

[0037] According to the invention, the outflow area of ​​the gas generator is divided into at least two zones, which are separated from each other by a separating area of ​​the outer housing without outflow openings. The zones with the outflow openings are preferably designed as axial zones, each with outflow openings distributed over the circumference.

[0038] According to the invention, a contact surface of the diffuser is positioned in the separation area between the zones. The contact surface positioned in the separation area divides the gas escaping from the two zones into two separate partial gas streams. Preferably, the diffuser has two collection chambers arranged adjacent to the contact surface positioned in the separation area, each of which collects the gas escaping from one of the two zones.

[0039] In such an embodiment, the axially rearwardly facing collection chamber has, for example, an outlet opening formed by an open section in a rearwardly facing side wall of the diffuser. A partial gas flow can exit from this outlet opening in an outlet direction directed away from the longitudinal end of the gas generator.

[0040] In such an embodiment, the axially front-side collection chamber has, for example, a circumferential outlet opening in the form of a radial gap. From this, a partial gas flow can exit in the opposite direction to the partial gas flow exiting the rear-side collection chamber.

[0041] The zones of the gas generator's outflow area can have a symmetrical distribution of the outflow openings. This allows the assembly to be designed to be thrust-neutral with respect to the gas flowing out of the gas generator, so that 50% of the gas exits through the outlet opening of the axially front and the axially rear collection chamber.

[0042] Alternatively, the zones of the gas generator's outflow area can also have a non-symmetrical distribution of the outflow openings, resulting in an uneven distribution of the gas flow. Such a percentage-uneven distribution of the gas flow can, for example, achieve a substantially uniform filling of gas bag chambers of different sizes located at the front and rear.

[0043] A significant advantage of such an assembly is that the diffuser can be designed as a standard component and the percentage gas distribution can be easily adjusted by adjusting the number of outlet openings assigned to the respective zones in the outlet area of ​​the gas generator.

[0044] The above-mentioned object is also achieved with a gas bag module comprising a gas bag and an assembly as described above, in which the diffuser is arranged entirely in an inflatable inner volume of the gas bag.

[0045] In this case, it is not necessary to completely seal the contact surfaces from the outer surface of the gas generator, as any leakage currents escape within the gas bag and thus cannot escape into the environment. Therefore, complex seals can be dispensed with, further reducing manufacturing costs.

[0046] In order to assemble an above-mentioned assembly, a method according to claim 14 with the following steps is provided. A one-piece diffuser is manufactured from a tubular element or from a metal sheet, wherein all contact surfaces and all gas guide surfaces are preformed. The prefabricated diffuser is pushed onto the outflow area of ​​the gas generator. To attach the diffuser to the gas generator, a contact surface of the diffuser is plastically deformed in the region of a bead of the gas generator, so that the contact surface engages at least partially or sectionally along the circumference in the bead and a positive connection is created. The plastic deformation of the contact surface in the region of the bead can preferably be produced by a pressing tool.

[0047] Alternatively, a method according to claim 15 with the following steps can be provided for assembling an above-mentioned assembly. A one-piece diffuser is manufactured from a closed tubular element or from a metal sheet, wherein all contact surfaces, all gas conducting surfaces and all locking elements are pre-formed. The diffuser is pushed onto the outflow area of ​​the gas generator so that the locking elements engage at least partially along the circumference into the bead of the gas generator, creating a positive locking connection. When the diffuser is pushed on, the contact surfaces with the adjoining locking elements bend radially outwards. When they reach the beads of the gas generator, the locking elements engage in the beads of the gas generator, so that the positive locking / locking of the diffuser to the gas generator can be achieved.

[0048] Direct attachment of the diffuser to the outer wall of the gas generator other than by clamping and / or pressing is not required and therefore not generally intended, but is nevertheless possible.

[0049] Due to this type of production, the use of a diffuser according to the invention is independent of the outer contour of the gas generator along its longitudinal axis.

[0050] The preferred material is sheet steel or a steel tube. Especially for a diffuser with a locking element, spring steel, especially intermediate-tempered spring steel, can also be used.

[0051] The invention is described in more detail below using several exemplary embodiments and with reference to the accompanying drawings. In the drawings: Figure 1 a schematic perspective view of a longitudinal end of a gas generator of an assembly according to the invention; Figure 2a schematic perspective view of an assembly according to the invention comprising a gas generator and a diffuser according to a first embodiment; Figure 3 the diffuser Figure 2 in a frontal view; Figure 4 an inventive gas bag module with an assembly of Figure 2 in a longitudinal section view; Figure 5 a schematic perspective view of an assembly according to the invention comprising a gas generator and a diffuser according to a second embodiment; Figure 6 a schematic perspective view of the diffuser of Figure 5; Figure 7 a schematic perspective view of an assembly according to the invention comprising a gas generator and a diffuser according to a third embodiment; Figure 8 the diffuser Figure 7 in a rear view; Figure 9 a schematic perspective view of a longitudinal end of a gas generator of an assembly according to the invention; Figure 10a schematic perspective view of an assembly according to the invention comprising a gas generator and a diffuser according to a fourth embodiment; Figure 11 a schematic longitudinal sectional view of the assembly Figure 10 ; Figure 12 a) to c) schematic views of various embodiments of a longitudinal end of a gas generator of an assembly according to the invention; Figure 13 a) to c) partially sectioned views of an assembly of a gas generator according to the invention with a diffuser according to a fifth embodiment; Figure 14 a schematic perspective view of the diffuser of Figure 13; Figure 15 a schematic perspective view of an assembly according to the invention comprising a gas generator and a diffuser according to a sixth embodiment; Figure 16 a schematic perspective view of an assembly according to the invention comprising a gas generator and a diffuser according to a seventh embodiment; Figure 17 a) and b) enlarged partial views of a front longitudinal end of the gas generator with the diffuser according to Figure 16 in a perspective a) rear and b) front view; Figure 18 the diffuser Figure 16 in a perspective front view; Figure 19 a first schematic longitudinal section of the assembly from Figure 16; Figure 20 a second schematic longitudinal section of the assembly Figure 16 during an assembly step of the diffuser; and Figure 21 the second schematic longitudinal section of the assembly of Figure 16 after completion of the assembly of the diffuser.

[0052] Figure 1shows an elongated gas generator 10 having, at one longitudinal end 12 of its outer housing 14, an outflow region 16 with a plurality of individual outflow openings 18 distributed over the circumference. In this case, the outflow openings 18 are formed in a filter housing of the gas generator 10, which is part of the outer housing 14 of the gas generator 10.

[0053] The outlet openings 18 are distributed uniformly along the circumferential direction U. No outlet openings 18 are provided on a cap closing the longitudinal end 12. When the gas generator 10 is activated, all of the generated gas flows out through the outlet openings 18 of the outlet region 16 in an outlet direction R GG extending in the radial direction r.

[0054] In the Figure 2 In the first embodiment of an assembly 20 shown, the outflow region 16 of the gas generator 10 is surrounded by a clamp-shaped diffuser 22 in the circumferential direction U.

[0055] The diffuser 22 has a central receiving opening 24 (see Figure 3 ), into which the outer casing 14 of the gas generator 10 projects and, in the case shown, also projects through. The longitudinal end 12 of the gas generator 10, or more precisely, its cap without an outlet opening, extends in this embodiment in the axial direction A (along the longitudinal axis of the gas generator 10) a short distance beyond the diffuser 22. This is also shown in Figure 4 to recognize.

[0056] Along the axial direction A, the diffuser 22 extends only over a section 26 which encompasses the outflow area 16 and which is only slightly wider than the outflow area 16 (see e.g. Figure 4 ).

[0057] On the inner side 28 of the receiving opening 24 of the diffuser 22, a gas guide surface 30 is formed, which extends over a large portion of the circumference of the outflow area 16, here approximately over 225°.

[0058] The gas guide surface 30 is spaced apart in the radial direction r from the outer housing 14 and the outlet openings 18, so that gas escaping from the outlet openings 18 enters the space between the outer housing 14 of the gas generator 10 and the gas guide surface 30 when the gas generator 10 is activated. The space between the gas guide surface 30 and the outer housing 14 thus forms a collection chamber 32 for the gas flowing out of the gas generator 10.

[0059] The collection chamber 32 is delimited in the axial direction A by two contact surfaces 34, which directly abut the outer housing 14 of the gas generator 10. In this example, both contact surfaces 34 extend over the entire circumference of the gas generator 10, so that the collection chamber 32 is closed in the axial direction A by the two contact surfaces 34.

[0060] The contact surfaces 34 also ensure a connection of the diffuser 22 to the gas generator 10. They rest under mechanical tension on the outer housing 14 of the gas generator 10 and hold the diffuser 22 to the outer housing 14 via a clamping force.

[0061] The diffuser 22 has a plurality of outlet openings 36 which are fluidly connected to the collection chamber 32 and from which the gas flowing out of the gas generator 10 leaves the diffuser 22 and thus the assembly 20.

[0062] The collection chamber 32 opens here at its two circumferential ends 37 into two outlet openings 36 opposite one another in the axial direction A. In the examples shown here, the surface of the outlet openings 36 is perpendicular to the axial direction A, so that the gas leaves the assembly 20 in an outlet direction RD along the axial direction A.

[0063] In this embodiment, a total of four outlet openings 36 are provided, two of which are directed in opposite directions, so that the gas flows out along the axial direction A in two opposite outlet directions RD. Compared to the outflow direction R GG, the outflowing gas in this example is deflected by 90° from the radial direction r into the axial direction A.

[0064] In this example, the area of ​​all outlet openings 36 is chosen to be the same size. Thus, the assembly 20 is thrust-neutral with respect to the gas flowing out of the gas generator 10. Alternatively, the area of ​​the outlet openings 36 located opposite each other in the axial direction A can also be chosen to be different sizes, thus achieving a non-uniform gas distribution (not shown).

[0065] In this embodiment, the outlet openings 36 are formed in that the gas guide surface 30 in an outlet region 38 has a greater distance in the radial direction r from the outer housing 14 of the gas generator 10 than in the region of the collection chamber 32. In the outlet region 38, a side wall 40, which connects the gas guide surface 30 and the adjacent contact surface 34, is interrupted, so that the outlet opening 36 is created.

[0066] In this embodiment, the outlet openings 36 are arranged symmetrically to each other in both opposite side walls 40.

[0067] Here, two spatially separated outlet areas 38 are provided, each with two opposite outlet openings 36, which are spaced apart by approximately 90° along the circumferential direction (see Figures 2 and 3 ).

[0068] Between these two outlet areas 38, a further, small collection chamber 32 is optionally formed, but it is also possible that the gas guide surface 30 essentially rests against the outer housing 14 of the gas generator 10 and, if necessary, covers some of the outflow openings 18.

[0069] When the assembly 20 is installed in a gas bag module, the gas generator 10 is pushed into a gas bag 42 until the longitudinal end 12 of the gas generator 10, including the outflow area 16 and the diffuser 22, lies completely in an inflatable inner volume 44 of the gas bag 42. This is Figure 4 indicated.

[0070] It is therefore not necessary for the contact surfaces 34 to seal the collection chamber 32 gas-tight to the outside, since all gas flowing out of the gas generator 10 is released within the gas bag 42. Small leakage currents can therefore be accepted.

[0071] The diffuser 22 is manufactured by forming a sheet metal strip, for example, made of sheet steel, into a diffuser blank using a punching and bending process (not shown). In this step, all gas guide surfaces 30 and contact surfaces 34 are preformed. This diffuser blank is bent in a further forming step around the outflow area 16 of the gas generator 10 in the circumferential direction U, whereby the contact surfaces 34 come into contact with the outer housing 14 of the gas generator 10 and the gas guide surface 30 also assumes its final position, so that the desired collection chamber(s) 32 are created between the gas guide surfaces 30 and the outer housing 14.

[0072] In an overlap section 46 (see Figures 5 and 6) Sections of the diffuser blank lie one above the other in the radial direction r and are in contact with each other. In this overlapping section 46, the diffuser blank is fastened to itself, for example, using a suitable welding process such as laser welding. The resulting weld seam 48 clamps the finished diffuser 22 to the gas generator 10 under mechanical prestress. The diffuser blank is fastened by a material bond only to itself, but not by a material bond to the gas generator 10.

[0073] In addition, the diffuser 22 can be attached to the gas generator 10 by a suitable joining method, for example crimping. For this purpose, the gas generator 10 can have a bead 60 (see Figure 4). To connect the diffuser 22 to the gas generator 10, the contact surface 34 of the diffuser is plastically deformed in the area of ​​the bead 60, so that the contact surface engages at least partially along the circumference in the bead 60 and a positive locking 62 is created (see Figure 6 ).

[0074] Alternatively, the diffuser 22 can be fully preformed before being applied to the outflow area 16. Such a diffuser 22 can also be manufactured from a sheet metal strip using a stamping and bending process or from a tubular element, for example, a steel tube. Preferably, such a diffuser 22 is attached to the gas generator 10 using a suitable joining process, for example, using a pressing tool, as described above.

[0075] The Figures 5 and 6show an assembly 20 according to a second embodiment. Since the individual elements differ only in their shape and position, but not in their function, the previously introduced reference numerals are retained.

[0076] In the second embodiment, the diffuser 22 is designed such that two collection chambers 32 are formed, which are spaced apart from one another along the circumferential direction U and which each open into its own outlet region 38. Each of the outlet regions has two outlet openings 36, which are arranged at opposite axial ends of the diffuser 22 and whose surfaces are directed in opposite directions along the axial direction A. Along the axial direction A, the outlet region 38 is continuous, and the collection chamber 32 opens centrally into the outlet region 38. In the circumferential direction U, between the two collection chambers 32 and between the two outlet regions 38, the contact surface 34 lies directly against the outer housing 14 of the gas generator 10.

[0077] In this example, the overlapping section 46 runs in the area of ​​the two outlet areas 38, so that in this section the metal sheet from which the diffuser 22 is made is double-layered and is fixed to one another at a suitable location, indicated here by the weld seam 48.

[0078] In this embodiment, too, the gas exiting the outflow region 16 of the gas generator 10 in the radial direction r is first diverted by 90° through the gas guide surface 30 into the collection chambers 32, where it is guided to the outlet regions 38, where it is again diverted by 90° and divided into two partial gas streams, which, in the illustrated embodiment, leave the diffuser 22 in opposite directions along the axial direction A with essentially the same intensity. The gas volume in the individual partial gas streams is determined by the number of outflow openings 18 in the region of the individual collection chambers 32.

[0079] The number, arrangement, shape, and size of the individual collection chambers 32, outlet areas 38, and outlet openings 36 are, of course, at the discretion of the person skilled in the art and can be adapted to the respective gas generator 10 and the respective application. In particular, the number, arrangement, shape, and size of the individual collection chambers 32, outlet areas 38, and outlet openings 36 can also be designed such that an uneven gas distribution occurs.

[0080] The Figures 7 and 8show a third embodiment of an assembly 20. In contrast to the embodiment just described, in the overlap section 46, the diffuser blank is not superimposed in the radial direction r, but rather two sections of the diffuser blank meet along the circumferential direction U and abut one another along the axial direction A and along the radial direction r. As described above, the diffuser blank is fixed to itself in this section, represented here by a weld seam 48.

[0081] A further difference from the embodiment just described is that a total of three collection chambers 32a, 32b are provided, each of which opens into only a single outlet opening 36a, 36b. Figure 7 shows the diffuser 22 in a frontal view from the longitudinal end 12 of the gas generator 10, while Figure 8 shows the diffuser 22 in a rear view.

[0082] Two first collection chambers 32a are spaced apart from each other in circumferential direction U and are shaped mirror-inverted with respect to a diameter of the gas generator 10. The gas guide surface 30 is shaped in these two first collection chambers 32a in such a way that a rearward-facing outlet opening 36a is formed in each case.

[0083] The third collection chamber 32b is located along the circumferential direction U between the first two described collection chambers 32a. It has a single outlet opening 36b, which is formed by a radial gap 50 between the diffuser 22 and the outer housing 14 of the gas generator 10 and thus also has its surface oriented perpendicular to the axial direction A, so that gas flows out in an outlet direction RD parallel to the axial direction A, but directed forward and thus opposite to the gas exiting from the outlet openings 36a.

[0084] The outlet opening 36b is located at an axial end 51 of the second collection chamber 32b.

[0085] As in the other embodiments, the areas of the individual outlet openings 36a, 36b, optionally 36, as well as the size of the collection chambers 32a, 32b, optionally 32 are selected such that the assembly 20 is substantially thrust-neutral.

[0086] Alternatively, an uneven gas distribution is also possible here by adjusting the surfaces of the individual outlet openings 36a, 36b and the size of the collection chambers 32a, 32b, whereby the size of the collection chambers 32a, 32b can be adjusted in particular by the position of the separating web 33 formed by the contact surface 34. Such a percentage-uneven distribution of the gas flow can, for example, achieve a substantially uniform filling of gas bag chambers of different sizes arranged at the front and rear.

[0087] At the rear axial end of the diffuser 22, a contact surface 34 extends over the entire circumference of the gas generator 10. A contact surface 34 at the front axial end of the diffuser 22 is interrupted in the region of the second collection chamber 32b. This section forms the radial gap 50.

[0088] In general, the longitudinal end 12 is considered to be the front end of the gas generator 10; terms such as "front" and "rear" refer to this orientation.

[0089] The Figures 10 and 11 show an assembly 20 according to a fourth embodiment.

[0090] This diffuser geometry can also be manufactured from a strip of sheet metal or a tubular element, for example, through a stamping and bending process. Alternatively, the diffuser can also be manufactured as a spiral-welded, seamless, or drawn-from-sheet component.

[0091] Here, in particular, a gas generator 10, as shown in Figure 9 The only difference to the one shown in Figure 1 A feature of the gas generator shown is that, in the axial direction A, the outflow region 16 is divided into two axial zones 52, 54, which are separated from one another by a separating region of the outer housing 14, designed as a strip, without outflow openings 18. In this case, it can be provided, particularly for an uneven gas distribution, that the zones 52 and 54 have a non-symmetrical division of the outflow openings 18.

[0092] The diffuser 22 of this embodiment has a central contact surface 34a positioned in the separation area between the two zones 52, 54. Thus, the central contact surface 34a divides the gas exiting the two zones 52, 54 into two separate partial gas streams.

[0093] The diffuser has two collecting chambers arranged along the axial direction A adjacent to the contact surface 34. Based on the embodiment just described, the reference numerals 32a, 32b are used for these collecting chambers.

[0094] Each of the collection chambers 32a, 32b collects the gas escaping from one of the zones 52, 54.

[0095] In this example, the rear collection chamber 32a has a single outlet opening 36a, which is formed by an open section of a rearward-facing side wall 40 and from which a partial gas flow exits in an outlet direction RD directed away from the longitudinal end 12 of the gas generator 10.

[0096] In this example, the front-side collection chamber 32b has a circumferential outlet opening 36b in the form of a radial gap 50, from which a partial gas flow exits in the opposite direction. This geometry is well suited to Figure 11 to recognize.

[0097] The Figures 12 a) to 12 c) each show the outer housing 14 of a gas generator 10, in which the outflow area 16 is divided in the axial direction A into two axial zones 52, 54, which are separated from one another by a separating area 68 of the outer housing 14, designed as a strip, without outflow openings 18.

[0098] In the Figures 12 a) and 12 b) In each case, an outer housing 14 of the gas generator 10 is shown, which is provided for an uneven gas distribution, whereby the zones 52 and 54 have a non-symmetrical division of the outlet openings 18. In the Figure 12 a) The outlet openings 18 are distributed between zones 52 and 54 in such a way that approximately two-thirds of the gas flow exits in the area of ​​zone 52 and approximately one-third of the gas flow exits in zone 54. In the Figure 12 b)the outlet openings 18 are distributed over the zones 52 and 54 in such a way that approximately one third of the gas flow exits in the area of ​​zone 52 and approximately two thirds of the gas flow exits in zone 54.

[0099] In the Figure 12 c) an outer housing 14 of the gas generator 10 is shown, which is provided for a uniform gas distribution, wherein the zones 52 and 54 have a symmetrical division of the outlet openings 18, so that approximately half of the gas flow exits in zone 52 and in zone 54.

[0100] Of course, the person skilled in the art can also produce other percentage ratios of the gas flow distribution by distributing the outflow openings 18 to the zones 52 and 54 in accordance with the intended use of the assembly 20.

[0101] The Figures 13 a) to 13 c)each show an assembly according to a fifth embodiment, wherein in the outer housing 14 of the gas generator 10 of the assembly 20 the outflow region 16 is divided in the axial direction A into two axial zones 52, 54, which are separated from one another by a separating region 68 of the outer housing 14 formed as a strip without outflow openings 18.

[0102] The diffuser 22 of this embodiment (see Figure 14 ) has a central contact surface 34a positioned in the separation area 68 between the two zones 52, 54. The diffuser 22 has two collection chambers 32a and 32b arranged adjacent to the contact surface 34a along the axial direction A. Each of the collection chambers 32a, 32b collects the gas escaping from one of the zones 52, 54. Thus, the central contact surface 34a divides the gas escaping from the two zones 52, 54 into two separate partial gas streams.

[0103] In the Figure 13 a)The outlet openings 18 are distributed between the zones 52 and 54 in such a way that in the area of ​​zone 52 approximately two thirds of the gas flow exits into the collection chamber 32b and in zone 54 approximately one third of the gas flow exits into the collection chamber 32a. Figure 13 b) The outlet openings 18 are distributed between the zones 52 and 54 in such a way that in the area of ​​zone 52 approximately one third of the gas flow exits into the collection chamber 32b and in zone 54 approximately two thirds of the gas flow exits into the collection chamber 32a. Figure 13 c) the outlet openings 18 are distributed symmetrically / uniformly between zones 52 and 54, so that approximately half of the gas flow in zone 52 exits into the collection chamber 32b and in zone 54 into the collection chamber 32a.

[0104] The rear collection chamber 32a in this example has a single outlet opening 36a, from which a partial gas flow exits in an outlet direction RD directed away from the longitudinal end 12 of the gas generator 10. The front collection chamber 32b in this example has an outlet opening 36b in the form of a radial gap 50, from which a partial gas flow exits in the opposite direction. The gap 50 is, as can be seen from the Figures 13 a) to 13 c) emerges, in the example shown, interrupted in the circumferential direction by the contact surface 34 at the longitudinal end 12.

[0105] This diffuser geometry can also be manufactured from a strip of sheet metal or a tubular element, for example, through a stamping and bending process. Alternatively, this diffuser can also be manufactured as a spiral-welded, seamless, or drawn-from-sheet component.

[0106] The advantage of such an assembly 20 according to the fifth embodiment is that the diffuser 22 can be designed as a standard component: An adjustment of the percentage gas distribution, which depends in particular on the intended use of the assembly 20, can be achieved in a simple and cost-effective manner by adapting the outer housing 14. The adaptation of the outer housing 14 is preferably achieved by adjusting the number of outflow openings 18 assigned to the respective zones 52 and 54 in the outflow area 16 of the outer housing 14 of the gas generator 10.

[0107] Figure 15 shows a sixth embodiment of an assembly 20. In contrast to the embodiment just described, the central contact surface 34a is helical, so that the axial width of the two collecting chambers 32a, 32b varies along the circumferential direction U.

[0108] The spiral shape of the central contact surface 34 is achieved here by this contact surface 34a having two first sections 56 running only along the circumferential direction U, which are arranged offset from one another along the axial direction A, as well as two second sections 58 running obliquely to the axial direction A and the circumferential direction U and which connect the first sections 56 to one another. This design allows the size of the individual collection chambers 32a, 32b, which determine the strength of the individual partial gas flows, to be determined. This geometry can be used with a gas generator according to Figure 1 as well as with a gas generator Figure 9 use.

[0109] In this embodiment, too, the rear collection chamber 32a has a rearward-facing outlet opening 36a, while the front collection chamber 32b has a forward-facing outlet opening 36b, which runs in the form of a radial gap at the front axial end 51 of the collection chamber 32b in the circumferential direction U around the gas generator 10.

[0110] The Figures 16 to 21 show an assembly 20 according to a seventh embodiment. Figure 16 shows a gas generator according to Figure 1 on whose longitudinal end 12 a self-locking diffuser 22 is placed. Similar to the first embodiment, the longitudinal end 12 of the gas generator 10, or more precisely, its cap without an outlet opening, also extends in this sixth embodiment in the axial direction A a short distance beyond the diffuser 22. This is particularly evident in the Figures 17, 19 and 21 easy to recognize.

[0111] The self-locking diffuser 22 is preferably made of spring steel. In the illustrated embodiment, the gas guide surface 30 extends over the entire circumference. At the front, the diffuser 22 has several outlet openings 36b, distributed evenly over the circumference U. The outlet openings 36b are separated by separating webs 33', which also form the front contact surfaces 34 (see Figures 17b and 18 ).

[0112] At the rear, the diffuser 22 in the embodiment shown has an outlet opening 36a, which is formed by a section-wise opening in the rear area of ​​the gas guide surface 30 (see Figures 17a and 19 ). In the illustrated embodiment, an optional guide element 64 is connected to the contact surface 34, which is arranged in the region of the outlet opening 36a. By means of such a guide element 64, the outlet direction RD of the gas can be deflected into an outlet direction RD (see Figure 19 ).

[0113] The rear contact surface 34 of the diffuser is divided into several sections in the circumferential direction U by separating recesses 66. In the embodiment according to the Figures 16 to 21 The rear contact surface 64 comprises four sections. Two of these sections of the contact surface 34, which are arranged here adjacent to the section of the contact surface 34 in the region of the outlet opening 36a, are adjoined by locking elements 62, which engage in the bead 60 of the gas generator 10 when the diffuser 22 is in the assembled state.

[0114] The Figures 20 and 21 show a longitudinal section through the assembly 20 in an xz plane at different times during the assembly of the diffuser 22 and the gas generator 10.

[0115] Figure 20shows the assembly 20 while the diffuser 20 is being pushed onto the gas generator 22. The contact surfaces 34 with the locking elements 62 are bent outward in the radial direction r when the diffuser 22 is pushed on. This bending of the locking elements 62 is made possible in particular by the separating recesses 66 in the area of ​​the rear contact surface 34.

[0116] Figure 21shows the assembly 20 after assembly has been completed. It can be clearly seen that the locking elements 62 have snapped into the bead 60 of the gas generator 10 and the diffuser 22 is thus easily locked to the gas generator 10. To fix the diffuser 22 to the gas generator 10, the separating webs 33', which form the front-side contact surfaces 34, can also be designed such that they are also bent at least slightly outwards in the radial direction r during assembly of the diffuser. As a result, the separating webs 33' can generate a contact force directed towards the central axis of the gas generator 10 in the area of ​​the front-side contact surfaces 34 due to the inherent stress of the material in the assembled state. Of course, in addition to the self-locking, the diffuser 22 can also be fixed to the gas generator 10, for example by pressing or welding.

[0117] All features of the individual embodiments can, of course, be combined or interchanged at the discretion of the person skilled in the art within the scope of protection of the patent claims, whereby the desired application and the geometry of the gas generator used must always be taken into account when selecting the shape of the diffuser.

Claims

1. An assembly (20) of an elongate inflator (10) having an outer housing (14) with outflow openings (18) distributed along the circumference (U) which define an outflow area (16) and an outflow direction (RGG), and of a clamp-type diffusor (22) enclosing the outflow area (16), specifically made of a formed sheet ring or tube element, wherein the diffusor (22) includes a central receiving opening (24) into which the outer housing (14) protrudes so that the diffusor (22) circumferentially encloses an axial portion of the outer housing (14) which comprises the outflow area (16), wherein on the inner side (28) of the diffusor (22) delimiting the receiving opening (24) at least one bearing surface (34; 34a) and at least one gas guiding surface (30) are provided, wherein the bearing surface (34; 34a) bears directly against the outer housing (14) of the inflator (10), wherein the outflow area (16) of the inflator (10) is divided into at least two zones (52, 54) which are separated from each other by a separation area (68) of the outer housing (14) without outflow openings (18), wherein the bearing surface (34a) of the diffusor (22) is positioned in the separation area (68) between the zones (52, 54), and wherein the at least one bearing surface (34a) divides the gas flow exiting the gas generator (10) into at least two partial flows, specifically wherein the bearing surface (34a) extends spirally around the outer housing (14) or only in the circumferential direction (U) around the outer housing (14), and the gas guiding surface (30) is radially spaced apart from the outer housing (14) while forming at least two collecting chambers (32; 32a, 32b) into which gas flowing out of the outflow area (16) flows, wherein each of the collecting chambers (32; 32a, 32b) opens into at least one outlet opening (36; 36a, 36b) through which gas exits the diffusor (22) from the inflator (10) in an outlet direction (RD) at right angles to the outflow direction (RGG), wherein the at least two outlet openings (36; 36a, 36b) are directed in opposite directions.

2. The assembly (20) according to claim 1, characterized in that the outlet direction (RD) extends axially in relation to the longitudinal axis of the inflator (10).

3. The assembly (20) according to any one of the preceding claims, characterized in that, adjacent to the outlet opening (36; 36a), the gas guiding surface (30) is located radially further outside than in the at least one associated collecting chamber (32; 32a) remote from the outlet opening (36; 36a).

4. The assembly (20) according to any one of the preceding claims, characterized in that the bearing surface(s) (34; 34a) delimit(s) the collecting chamber(s) (32; 32a, 32b) in the axial direction (A) and / or in the circumferential direction (U).

5. The assembly (20) according to any one of the preceding claims, characterized in that at least one collecting chamber (32; 32a) is provided which does not extend continuously in the circumferential direction (U) and which, at its two circumferential ends (37), opens into at least one outlet opening (36; 36a).

6. The assembly (20) according to any one of the preceding claims, characterized in that a collecting chamber (32b) is provided which opens at an axial end (51) into an outlet opening (36b).

7. The assembly (20) according to claim 6, characterized in that the outlet opening (36b) is formed by a radial gap (50) between the outer housing (14) and the inner side of the diffusor (22).

8. The assembly (20) according to any one of the preceding claims, characterized in that a bearing surface (34a) peripheral around the entire circumference of the inflator (10) is provided which includes two first portions (56) extending only along the circumferential direction (U) and two second portions (58) extending inclined to the circumferential direction (U) and to the axial direction (A), the second portions (58) connecting the first portions (56).

9. The assembly (20) according to any one of the preceding claims, characterized in that the outflow area (16) is provided at a longitudinal end (12) of the inflator (10).

10. The assembly according to any one of the preceding claims, characterized in that the outlet openings (36b) are distributed over the circumference (U) and are separated by separation webs (33'), wherein the separation webs (33') at least partially form the bearing surface(s) (34, 34a) which delimit(s) the collecting chamber (32) in the axial direction (A), specifically toward a longitudinal end (12) of the inflator (10).

11. The assembly (20) according to any one of the preceding claims, characterized in that the diffusor (22) comprises at least one detent element (62), wherein the detent element (62) can engage specifically in a bead (60) for fastening and fixing the diffusor (22) on the inflator (10).

12. The assembly according to claim 11, characterized in that the diffusor (22) is manufactured of spring steel, specifically an austempered spring steel.

13. An airbag module comprising an airbag (42) and an assembly (20) according to any one of the preceding claims, characterized in that the diffusor (22) is arranged completely in an inflatable inner volume (44) of the airbag (42).

14. A method of mounting an assembly (20) according to any one of the claims 1 to 13, comprising the following steps: - a one-piece diffusor (22) is manufactured of a one-piece closed tube element or of a sheet metal, wherein all bearing surfaces (34; 34a) and all gas guiding surfaces (30) are preformed, - the diffusor (22) is slipped onto the outflow area (10) of the inflator and a bearing surface (34) of the diffusor (22) is plastically deformed in the area of a bead (60) of the inflator, specifically by a pressing tool, so that at least portions of the bearing surface (34) engage in the bead (60) along the circumference (U) and a positive locking (62) is formed.

15. A method of mounting an assembly (20) according to any one of the claims 1 to 13, comprising the following steps: - a one-piece diffusor (22) is manufactured of a closed tube element or of a sheet metal, wherein all bearing surfaces (34; 34a), all gas guiding surfaces (30) and all detent elements (62) are preformed, - the diffusor (22) is slipped onto the outflow area (16) of the inflator (10) so that at least portions of the detent elements (62) engage in the bead (60) of the inflator (10) along the circumference (U) and a positive locking is formed.