Gas generator with holding device

Abstract

Gas generator (100) for an airbag module (150), comprising a diffuser chamber (130) and at least one combustion chamber (110) commensurate with the diffuser chamber for receiving combustible propellant bodies (113, 115, 117), wherein a partition (200; 400) is arranged between the combustion chamber (110) and the diffuser chamber (130), the partition having a number of passage openings (201, 202; 405, 406), the partition (200; 400) having a retaining device (250; 450) formed integrally with the partition (200; 400) and arranged in the combustion chamber (110), which is designed to completely cover the passage openings (201, 202; 405, 406) during operation of the gas generator (100) by individual to prevent fuel bodies (113, 115, 117), characterized in that the partition (200; 400) is disc-shaped and the passage openings (201, 202, 203, 204, 205, 206, 208;401, 403, 402, 404, 405, 408) are designed as through-holes arranged on concentric circular paths (282, 284, 286; 482, 484, 486) or radially in a star shape, wherein the retaining device (250; 450) either has at least one annular, groove-like recess (252) on the partition (200) connecting at least two through-holes (201, 202) or has at least one annular, ridge-like projection (456) on the partition (400) formed between at least two through-holes (405, 406).

Description

[0001] The present invention relates to a gas generator for an airbag module, comprising a diffuser chamber and at least one combustion chamber connectable thereto for receiving combustible propellant particles, wherein a partition wall having a number of through-openings is arranged between the combustion chamber and the diffuser chamber. The present invention further relates to an airbag module with such a gas generator.

[0002] Currently, such a gas generator for an airbag module is known, in which combustible propellant bodies, e.g., pressed propellant tablets or pellets, form a so-called propellant bed arranged in a combustion chamber. This combustion chamber is connected to an associated diffuser chamber via a partition wall with a number of perforations. When this propellant bed burns in the combustion chamber, the propellant tablets burn towards the partition wall, generating a hot gas under high pressure. This gas flows through the perforations into the diffuser chamber, from where it is introduced, for example, into an associated gasbag.

[0003] In conventional baffles, which are designed as flat discs with a uniform thickness and essentially cylindrical through-holes of constant diameter to form the passage openings, individual fuel pellets can cover or block several or all of these through-holes as the fuel bed burns. This can lead to an undesirably high pressure in the combustion chamber, as the resulting hot gas cannot escape from the combustion chamber or flow into the diffuser chamber. To prevent this, an additional flow-permeable component is placed between such a baffle and the associated fuel bed, e.g., a...A mesh screen or a retaining sieve is used to prevent the passage holes in the partition from being covered by individual fuel pellets during the combustion of the fuel bed, and to allow fuel to flow behind the pellets by spacing the fuel bed from the partition. A disadvantage of this is that such an additional component requires additional installation space in the gas generator and incurs additional manufacturing and assembly costs.

[0004] From US patent 5,725,245 A, a gas generator for an airbag module is known, comprising a diffuser chamber and at least one combustion chamber commensurate with it for receiving combustible propellant particles, wherein a partition wall is arranged between the combustion chamber and the diffuser chamber, the partition wall having a number of passage openings, the partition wall having a retaining device formed integrally with the partition wall and arranged in the combustion chamber, which is designed to prevent individual propellant particles from completely covering the passage openings during operation of the gas generator.

[0005] Furthermore, a gas generator is known from the publication DE 201 07 130 U1, which has a diffuser chamber and at least one combustion chamber which can be brought into fluid contact with it for receiving combustible propellant bodies, wherein a partition wall is arranged between the combustion chamber and the diffuser chamber which has a number of passage openings.

[0006] A similar construction is also known from the publication DE 198 51 262 A1.

[0007] One disadvantage of these known designs is that, during operation of the gas generator, an advantageous backflow of fuel bodies located in the area of ​​the passage openings of the partition is hardly possible or only very unsatisfactorily possible.

[0008] The object of the invention is therefore to make a gas generator for an airbag module more effective with regard to its construction and assembly, so that the backflow of propellant bodies arranged in the area of ​​the passage openings of the partition is optimized. Furthermore, the invention aims to provide an airbag module with such a gas generator.

[0009] For a gas generator as described in US 5,725,245 A, this problem is solved according to the invention by having the partition wall in a disk shape and the passage openings as through-holes arranged on concentric circular paths or radially in a star shape, wherein the holding device either has at least one annular, groove-like recess on the partition wall that connects at least two passage openings or has at least one annular, ridge-like elevation on the partition wall that is formed between at least two passage openings.

[0010] The partition wall equipped with the free-holding device simplifies the construction of the gas generator, reliably preventing a large-area, i.e., essentially complete, covering of the partition wall's passage openings during combustion of the fuel bodies in the combustion chamber.

[0011] According to the invention, the holding device has at least one groove-like recess formed on the partition wall.

[0012] Such a groove-like recess can be formed cost-effectively on the partition wall and allows for a simple backflow of fuel particles against the partition wall.

[0013] The at least one groove-like recess formed on the partition wall at one end face of the partition wall facing the combustion chamber connects at least two passage openings to each other.

[0014] Thus, even if the two passage openings are covered by corresponding fuel bodies, a gas produced during the combustion of the fuel particles in the combustion chamber can still reach the passage openings via the groove-like recess and thus escape from the combustion chamber through a backflow of these fuel particles, effectively preventing an unacceptably high pressure increase in the combustion chamber.

[0015] Preferably, at least one groove-like recess formed in the partition is provided in an annular shape on an end face of the partition facing the combustion chamber and connects a plurality of passage openings. Further preferably, at least one groove-like recess formed in the partition is provided in the radial direction of the partition on an end face of the partition facing the combustion chamber. Particularly preferably, at least two groove-like recesses formed in the partition are provided on an end face of the partition facing the combustion chamber, wherein at least two recesses are parallel or intersecting.

[0016] Thus, even when several passage openings are covered by corresponding fuel bodies, a safe and reliable backflow of these fuel bodies can be enabled in a simple manner.

[0017] According to the invention, the free-holding device has at least one bulge formed on the partition wall, which is formed as a ridge-like elevation between at least two passage openings.

[0018] Such a bulge can be formed cost-effectively on the partition wall and allows for a simple backflow of the fuel bodies located against the partition wall in the area of ​​the bulge.

[0019] This allows for the formation of a simple and stable bulge on the partition wall.

[0020] Preferably, the ridge-like elevation is provided in a ring shape on one end face of the partition wall facing the combustion chamber.

[0021] It is further preferred that a rib-like projection be provided in the radial direction of the partition on an end face of the partition facing the combustion chamber. Particularly preferred are at least two rib-like projections provided on an end face of the partition facing the combustion chamber, wherein at least two rib-like projections are parallel to or intersecting with each other.

[0022] Thus, a robust partition wall can be provided, the stiffness of which is easily improved by the ring-shaped bridge, while ensuring that complete covering of the passage openings adjacent to the bridge by corresponding fuel bodies is safely and reliably prevented during the combustion of the fuel bodies.

[0023] According to one embodiment, at least one of the passage openings is closed with a damping, preferably on the front side of the partition wall facing the diffuser space.

[0024] Thus, the pressure in the combustion chamber, which is formed by the combustion of the fuel particles, can be influenced.

[0025] According to one embodiment, the fuel bodies have pressed fuel tablets.

[0026] This allows for the use of simple and cost-effective fuel bodies.

[0027] Preferably, the holding device is designed to allow a backflow of fuel bodies arranged in the area of ​​the passage openings when the fuel bodies are burning during operation of the gas generator.

[0028] Thus, even when several passage openings are covered by corresponding fuel bodies, a safe and reliable backflow of these fuel bodies can be enabled in a simple manner.

[0029] The object of the invention relating to the airbag module is solved by an airbag module according to the invention, comprising a gas generator, a gas bag inflatable by the gas generator and a fastening device for attaching the airbag module, in particular in the interior of a vehicle, wherein the gas generator is designed according to at least one of claims 1 to 9.

[0030] Further details and advantageous embodiments of the invention will become apparent from the exemplary embodiments described below and illustrated in the figures, which are in no way to be understood as limiting the invention. The figures show: Fig. 1 A schematic, partially perspective view of an airbag module with a gas generator according to one embodiment, Fig. 2 a perspective view of a partition wall of the gas generator of Fig. 1, Fig. 3 a sectional view of the gas generator of Fig. 1 with fuel bodies provided therein, and Fig. 4 a perspective view of a gas generator from Fig. 1 usable partition wall according to an alternative embodiment.

[0031] In the following description, the terms left, right, front, back, top, and bottom refer to the respective figure in the drawing and may vary from one figure to the next depending on the chosen orientation (portrait or landscape). Identical or similarly appearing parts are designated with the same or corresponding reference symbols (e.g., 107, 207, 307, etc.) in the different figures and are usually described only once.

[0032] Fig. Figure 1 shows an exemplary gas generator 100 according to one embodiment, which is illustrated by an airbag module 150 for a motor vehicle steering wheel. It should be noted, however, that for the sake of simplicity and clarity of the drawing, the airbag module 150 is shown only schematically, while the gas generator 100 is shown in perspective.

[0033] The gas generator 100 is shown, for illustrative purposes, as having a cylindrical housing 105 with an interior 107 formed by the housing. Two closures 160, 170 are arranged at the end faces of the housing 105, for example, which may be equipped with ignition units (165 in) including associated electric igniters. Fig. 3) or 175. Such ignition units are well known to those skilled in the art. Therefore, for the sake of brevity, a detailed description of suitable ignition units is omitted here.

[0034] Between the closures 160, 170, a first and a second flow-permeable partition 200, 300 are arranged in the interior 107 of the housing 105 for illustrative purposes. Between the partitions 200, 300, a diffuser chamber 130 is formed in the housing 105 by way of example; this chamber may optionally include a filter (not shown). In the area of ​​this diffuser chamber 130, a radial opening 131 is formed on the housing 105, in which, for example, a membrane (138) is inserted. Fig. 3) A closed diffuser 132 with a plurality of outlet openings 135 is attached. The diffuser 132 is, for example, arranged within a gas bag associated with the airbag module 150.

[0035] Furthermore, the first partition 200 serves to delimit a first combustion chamber 110 formed between the breech 160 and the first partition 200 in the housing 105. The second partition 300 serves to delimit a second combustion chamber 120 formed between the breech 170 and the second partition 300 in the housing 105. The first combustion chamber 110 is, for example, for receiving a first propellant bed (112 in Fig. 3) and the second combustion chamber 120 for receiving a second fuel bed (122 in Fig. 3) designed. However, it should be noted that the description of two combustion chambers is merely exemplary and is not to be understood as a limitation of the invention. Rather, it can also be applied when using a single combustion chamber or three or more.

[0036] According to the embodiment in Fig. 1 is on the first partition wall 200 a plurality of passage openings 202, 204, 206, 208, 210 (as well as 201, 203, 205 in Fig. 3) formed. Furthermore, the first partition 200 illustrates a holding device 250 arranged in the combustion chamber 110, which is designed to cover passage openings 202, 204, 206, 208, 210 (as well as 201, 203, 205 in) during operation of the gas generator 100. Fig. 3) as in Fig. 3 described to prevent. The holding device 250 is exemplified on one end face 299 of the partition 200 facing the combustion chamber 110 and is located at the bottom at Fig. 2 described in detail.

[0037] The second partition 300 is shown with a plurality of passage openings 302, 304, 306, 308, 310. Furthermore, the second partition 300 also has a retaining device on one end face 399 facing the combustion chamber 120. This device is designated 350 and its design is structurally identical to that of the retaining device 250. Therefore, for the sake of brevity, a detailed description of this retaining device 350 is omitted here. In general, a further description of the partition 300 is omitted below, as it preferably has a similar structure to the partition 200 described in detail below. Optionally, at least one of the passage openings 201, 203, 205, 301, 303, 305 can be closed with a sealing 500. Fig. Figure 1 shows such a seal 500 on the end face of the partition 200, 300, which faces the diffuser chamber 130, in which all passage openings 301, 303, 305 are closed. Such a seal 500 can, for example, be made of a foil or plate of metal (e.g., steel, aluminum, or copper) with a coating of adhesive on one side. Such a seal 500 can be applied (glued) to the substantially flat end face of the partition 200, 300 opposite the holding device 250, 350. In particular, such a dam 500 can be used in so-called "pyrotechnic gas generators" which, prior to activation of the gas generator 100, do not have a chamber under higher pressure (e.g., 200–500 bar), such as a combustion chamber 110, 120 or a diffuser chamber 130. Such a dam 500 only opens at a predetermined burst pressure. This means that the dam 500 ruptures when a certain pressure is reached, which is generated by the combustion of the propellant bodies 122, 123, and can thus contribute to controlling the pressure that develops in the combustion chamber 110, 120.

[0038] Fig. Figure 2 shows the exemplary disc-shaped partition wall 200 of Fig. 1 with the retaining device 250 provided on its end face 299 and a plurality of passage openings, of which, for the sake of simplicity of the drawing, only the openings 201, 202, 203, 204, 205, 206, 208, 210 are shown. The passage openings 201, 202, 203, 204, 205, 206, 208, 210 are, for example, cylindrical through-bores with at least substantially identical and constant diameters, which are arranged on concentric circular paths 282, 284, 286. For illustrative purposes, the passage openings 201, 202, 205, 208 are arranged on an outer concentric circular path 282, the passage openings 203, 206, 210 on an inner concentric circular path 286 and the passage opening 204 on a middle concentric circular path 284.

[0039] According to the embodiment in Fig. 2 The holding device 250 has at least one and, for illustrative purposes, three groove-like recesses 252, 254, 256 formed on the partition wall 200. These groove-like recesses 252, 254, 256 are, for illustrative purposes, formed in a ring shape on the end face 299 along the associated concentric circular paths 282, 284 and 286 respectively, but can also be oriented differently, e.g. in the radial direction of the partition wall 200.

[0040] At least one of the groove-like recesses 252, 254, 256 connects, by way of example, at least two of the passage openings 201, 202, 203, 204, 205, 206, 208, 210 to each other on the end face 299 of the partition 200. For illustrative purposes, the groove-like recesses 252, 254, 256 each connect a plurality of passage openings to each other in a ring-like arrangement; for example, the ring-shaped groove 252 connects the passage openings 201, 202, 205, 208, and the ring-shaped groove 256 connects the passage openings 203, 206, 210 to each other.

[0041] Fig. Figure 3 shows the gas generator 100 from Fig. Figure 1 illustrates the flow-permeable connection of the diffuser chamber 130 with the first combustion chamber 110 via the through-openings 201, 203, 205 provided in the first partition wall 200, as well as the flow-permeable connection of the diffuser chamber 130 with the second combustion chamber 120 via the through-openings 301, 303, 305 provided in the second partition wall 300. Furthermore, it illustrates Fig. 3 an exemplary membrane 138 provided for closing the diffuser space 130 in the area of ​​the simplified diffuser 132 at the opening 131. It should be noted that the membrane 138 is only required if the diffuser chamber 130 and the combustion chambers 110, 120 are filled with a pressurized gas that is inert until the gas generator 100 is activated, e.g., argon, helium, or a mixture thereof, at a filling pressure of approximately 250 to 500 bar, and the gas generator 100 is thus designed as a so-called "hybrid gas generator," so that the membrane 138 prevents the inert pressurized gas from escaping. If the gas generator 100 is designed as a so-called "pyrotechnic gas generator," the use of the membrane 138 can be omitted.

[0042] According to one embodiment, as described, for example, by Fig. As explained in Figure 3, a first fuel bed 112 is arranged in the first combustion chamber 110 and a second fuel bed 122 in the second combustion chamber 120. The first fuel bed 112 is illustrated by a plurality of pressed, combustible fuel tablets or pellets, of which only fuel tablets 113, 115, and 117 are labelled for clarity of the drawing. The second fuel bed 122 is also illustrated by a plurality of pressed, combustible fuel tablets or pellets, of which only fuel tablets 123, 125, and 127 are labelled for clarity of the drawing.

[0043] During operation or activation of the gas generator 100, the propellant bed 112 is ignited by an electric igniter 165 located on the closure 160, and the propellant bed 122 is ignited by the electric igniter 175 located on the closure 170. Subsequently, the propellant tablets 113, 115, 117 burn from the electric igniter 165 towards the partition 200, generating a hot gas under high pressure, which flows, for example, through the passage openings 201, 203, 205 into the diffuser chamber 130. The propellant tablets 123, 125, 127 burn from the electric igniter 175 towards the partition 300, also generating a hot gas under high pressure, which then flows, for example, through the passage openings 201, 203, 205 into the diffuser chamber 130. B. through the passage openings 301, 303, 305 into the diffuser chamber 130. This is prevented by the retaining devices 250, 350 or their groove-like recesses (252, 254, 256 of Fig. 2) prevents individual fuel tablets from completely covering the passage openings 201, 203, 205 or 301, 303, 305 and allows backflow of fuel bodies arranged in the area of ​​the passage openings 201, 203, 205 or 301, 303, 305, so that the hot gas generated in the combustion chambers 110, 120 can flow almost unhindered into the diffuser chamber 130.

[0044] Fig. Figure 4 shows a partition wall 400 according to an alternative embodiment, which is used to realize the partition walls 200, 300 of Fig. 1 and Fig. 3. Application. The partition 400 has, for illustrative purposes, a multitude of through-holes, of which only openings 401, 402, 403, 404, 405, 406, and 408 are labelled for the sake of simplicity. The through-holes 401, 402, 403, 404, 405, 406, and 408 are, for example, cylindrical through-bores with at least substantially identical and constant diameters, arranged, by way of example, on concentric circular paths 482, 484, and 486. For illustrative purposes, the passage openings 401, 403 are arranged on an outer concentric circular path 482, the passage openings 405, 408 on an inner concentric circular path 486 and the passage openings 402, 404, 406 on a middle concentric circular path 484.

[0045] According to one embodiment, as described, for example, by Fig. As explained in section 4, the partition wall 400 has a retaining device 450 which has at least one projection formed on an end face 499 of the partition wall 400, which is provided between at least two passage openings and preferably forms a rib-like elevation. For illustrative purposes, a projection 440 is formed between the passage openings 405, 408.

[0046] According to a further embodiment, at least one annular, rib-like projection is formed on the end face 499, which is associated with the release device 450. For illustrative purposes, three annular ribs 452, 454, 456 are formed on the end face 499, wherein the annular rib 456 is arranged between the concentric circular paths 486 and 484, the annular rib 454 is arranged between the concentric circular paths 484 and 482, and the annular rib 452, by way of example, extends outside the concentric circular path 482. The annular ribs 452, 454, 456 and the projection 440 fulfill the same function as the annular grooves 252, 254, 256 of Fig. 2, so that, for the sake of brevity, a detailed description of the functionality of the holding device 450 can be omitted here.

[0047] Naturally, numerous variations and modifications are possible within the scope of the present invention. For example, the following can be modified: Fig. 2 and Fig.The embodiments of partitions 200 and 400 described in section 4 can be combined with one another in any way, such that a corresponding partition can have both annular grooves and annular webs. Such variations and modifications are to be considered disclosed by the present description. In particular, embodiments are also conceivable that combine individual features of the embodiments described above.

Claims

[1] Gas generator (100) for an airbag module (150), comprising a diffuser chamber (130) and at least one combustion chamber (110) commensurate with the diffuser chamber for receiving combustible propellant bodies (113, 115, 117), wherein a partition (200; 400) is arranged between the combustion chamber (110) and the diffuser chamber (130), the partition having a number of passage openings (201, 202; 405, 406), the partition (200; 400) having a retaining device (250; 450) formed integrally with the partition (200; 400) and arranged in the combustion chamber (110), which is designed to completely cover the passage openings (201, 202; 405) during operation of the gas generator (100). 406) by individual propellant bodies (113, 115, 117), characterized by, that the partition (200; 400) is disc-shaped and the passage openings (201, 202, 203, 204, 205, 206, 208; 401, 403, 402, 404, 405, 408) are designed as through-holes arranged on concentric circular paths (282, 284, 286; 482, 484, 486) or radially in a star shape, wherein the retaining device (250; 450) either has at least one annular, groove-like recess (252) on the partition (200) connecting at least two passage openings (201, 202) or has at least one annular, rib-like projection (456) on the partition (400) connecting at least two passage openings (405, 406) is trained. [2] Gas generator according to claim 1, characterized by , that the groove-like recess (252) is formed on an end face (299) of the partition (200) facing the combustion chamber (110). [3] Gas generator according to at least one of the preceding claims 1 or 2, characterized by, that the at least one groove-like recess (252) formed on the partition (200) is provided in an annular shape on an end face (299) of the partition (200) facing the combustion chamber (110) and connects a plurality of passage openings (201, 202, 205, 208) together. [4] Gas generator according to at least one of the preceding claims, characterized by , that at least two groove-like recesses (252, 254) formed on the partition (200) are provided on an end face (299) of the partition (200) facing the combustion chamber (110), wherein at least two recesses (252, 254) are parallel or intersecting to each other. [5] Gas generator according to claim 1, characterized by , that the ridge-like elevation (452, 454, 456) is provided in a ring shape on one end face (499) of the partition wall (400) facing the combustion chamber (110). [6] Gas generator according to one of claims 1 or 5, characterized by, that at least two rib-like projections (452, 454, 456) are provided on one end face (499) of the partition wall (400) facing the combustion chamber (110), wherein at least two rib-like projections (452, 454, 456) are parallel to each other or intersecting. [7] Gas generator according to at least one of the preceding claims 1 to 6, characterized by , that at least one of the passage openings (201, 202, 203, 204, 205, 206, 208) is closed with a damping (500). [8] Gas generator according to at least one of the preceding claims 1 to 7, characterized by , that the propellant bodies (113, 115, 117) consist of pressed propellant tablets. [9] Gas generator according to at least one of the preceding claims 1 to 8, characterized by, that the holding device (250) is designed to allow a backflow of fuel bodies (113, 115, 117) arranged in the area of ​​the passage openings (201, 203, 205) when the fuel bodies (113, 115, 117) are burned during operation of the gas generator (100). [10] Airbag module comprising a gas generator (100), a gas bag inflatable by the gas generator (100) and a fastening device for attaching the module inside a vehicle, characterized by , that the gas generator (100) is designed according to at least one of claims 1 to 9.

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