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CN-109416235-B - Gas generator

CN109416235BCN 109416235 BCN109416235 BCN 109416235BCN-109416235-B

Abstract

The cylindrical pyrotechnic generator comprises: -a housing (10) with diffusion holes (13), -a pyrotechnic substance (20) accommodated in the housing (10), -a filter device (30) mounted in the housing (10), -an enveloping device (40; 40') mounted in the housing (10) between the pyrotechnic substance (20) and the filter device (30), -a discharge device (40; 40') mounted in the housing (10) between the pyrotechnic substance (20) and the enveloping device, characterized in that the filter device (30) is mounted to provide at least support for a support part of the enveloping device (40; 40') at the start of operation of the gas generator.

Inventors

  • PRIMA GERALD

Assignees

  • 奥托立夫开发公司
  • 奥托立夫开发公司

Dates

Publication Date
20220930
Application Date
20170628
Priority Date
20170628

Claims (14)

  1. 1. A cylindrical pyrotechnic gas generator comprising: -a housing (10) with a diffusion hole (13), -a pyrotechnic substance (20) housed in a casing (10), -a filter device (30) mounted in the housing (10), -an enveloping means (40; 40') mounted inside the casing (10) between the pyrotechnic substance (20) and the filter means (30), -a discharge device arranged in the housing (10) between the pyrotechnic substance (20) and the packing means, characterized in that the filter device (30) is arranged to provide support for at least a support portion of the packing means (40; 40') at the start of operation of the gas generator, wherein the unsupported portion is broken by forming lobes (42) in the voids left by the filter (30), wherein the size of the unsupported portion is determined by the size of the filter serving as a support, wherein the housing (10) comprises: -a base (11) supporting a pyrotechnic substance (20), and -a diffuser (12) welded to the base (11) and provided with diffusing holes (13), and a sealing device (40; 40') welded to the housing (10), wherein the containment device is a seal that is a metal cylinder welded directly to the diffuser, the containment device having a thickness that is less than 60% of a thickness of the housing.
  2. 2. Gas generator according to claim 1, wherein the non-supported part of the enclosing means (40; 40') is opposite to the gap left by the filtering means (30).
  3. 3. Gas generator according to claim 1 or 2, wherein at least one surface of the filtering means (30) is supported by a wall of the housing (10).
  4. 4. Gas generator according to claim 1 or 2, wherein the surface supported by the housing (10) is opposite to the surface of the filter device (30) providing support for the enclosing means (40; 40').
  5. 5. Gas generator according to claim 1 or 2, wherein the diffusion holes (13) form nozzles for controlling the combustion of the pyrotechnic substance (20).
  6. 6. Gas generator according to claim 1 or 2, wherein a space (d) is established between the filter means (30) and the diffusion hole (13).
  7. 7. The gas generator according to claim 1 or 2, wherein a space (d) is established between the downstream surface of the filtering means (30) and the wall of the housing (10) penetrated by the diffusion holes (13), and the thickness in the region of the diffusion holes (13) is at least 1 mm.
  8. 8. The gas generator according to claim 1 or 2, wherein the enclosing means (40; 40') is leak-proof connected to the housing.
  9. 9. Gas generator according to claim 1 or 2, wherein the base (11) is inertia welded to the diffuser (12), the enclosing means (40; 40') comprising indexing means rotating with respect to the base (11) or the diffuser (12), so that the indexing means is inertia welded to the diffuser (12) or the base (11) while the base (11) is inertia welded to the diffuser (12).
  10. 10. The gas generator according to claim 1 or 2, wherein the enclosing means (40; 40') comprises a metal cylinder and an O-ring arranged between the metal cylinder and the housing (10) forming a leak-proof seal.
  11. 11. Gas generator according to claim 1 or 2, comprising an ignition device (70), the pyrotechnic substance (20) being mounted opposite a side of the ignition device (70) and/or opposite an end of the ignition device (70).
  12. 12. Gas generator according to claim 1 or 2, wherein the filter means (30) has a central recess, and wherein the housing (10) and/or the enclosing means (40; 40') has a centering protrusion cooperating with the central recess.
  13. 13. The gas generator of claim 1 wherein the unsupported portion is entirely broken after ignition.
  14. 14. Assembly of a gas generator according to one of the preceding claims, comprising an ignition device (70) in which the housing is formed by a base (11) and a diffuser (12) with diffusion holes (13), the assembly process involving the steps of: -fixing the ignition device (70) to the base (11), -loading by gravity from a loading opening of the base (11) the pyrotechnic substance (20) into the base (11) in contact with the ignition device (70), -positioning a discharge device between the pyrotechnic substance (20) and the loading opening of the base (11), -positioning the packing device (40; 40') above the discharge device and in the region of the loading opening, -positioning the filtering means (30) above the wrapping means (40; 40'), -welding the diffuser (12) to the combustion chamber so that the filtering means (30) are interposed between the enveloping means (40,40') and the wall of the diffuser (12) in order to block the loading opening with the enveloping means (40; 40').

Description

Gas generator The present invention relates generally to gas generators, such as airbags, that provide generator gas to passive safety devices of automobiles. In particular, the invention relates to a pyrotechnic gas generator in which generator gas is generated by combustion of a gas generant, characterised by a cylindrical housing holding a loose tablet-like gas generant or pyrotechnic material. Cylindrical gas generators are known from the prior art, such as the generator disclosed in document EP2195206a 2. In contrast, the gas generator referred to in this document is particularly characterized by a thick plate internal structure, which must constitute a combustion chamber wall capable of withstanding high-pressure operation, which increases the cost of the vehicle and the load-bearing capacity of the vehicle. In fact, the thick plate fixed nozzle described herein (the smallest part through which the gas generator gases flow, which determines the combustion pressure of the pyrotechnic substance, i.e. the highest pressure of the whole gas generator) must therefore be able to withstand this high combustion pressure. Also, when considering the diffuser made of thick metal sheet and crimped to the gas generator referred to in this document, weight and cost are important concerns. One of the objectives of the present invention is to solve the above-mentioned drawbacks of the prior art documents, and in particular to provide a pyrotechnic gas generator which has a simple internal structure, does not have bulky components, and provides a stable operating mode and a fast manufacturing process without requiring complex steps. Accordingly, the present invention relates in a first aspect to a cylindrical pyrotechnic gas generator comprising: -a housing with a diffusion hole, -a pyrotechnic substance housed within the housing, -a filter device mounted in the housing, -an enclosure means mounted within the housing between the pyrotechnic substance and the filter means, -a discharge device mounted in the housing between the pyrotechnic substance and the packing device, characterised in that the filter means is arranged to provide support for at least the support member of the enclosure means when the gas generator is initially in operation. According to this implementation, when the gas generator is configured, the wrapping means is directly supported by the filtering means, so that no further support is required, which makes the internal structure of the gas generator simpler and lighter. In fact, the function of the packing means is only to ensure the leaktightness of the pyrotechnic substance and its release at a predetermined pressure upon ignition of the generator. Since the packing means is supported by the filter means, this way, reducing the thickness of the packing means does not impair its opening pressure. In other words, the filter device ensures a controlled deformation and opening of the enclosing device by preventing the enclosing device from collapsing, due to the support provided by the filter device. Finally, support is provided at least at the start of operation. For example, between the point at which the internal pressure of the pyrotechnic substance begins to increase after ignition and the point when the enclosure is opened or unsealed. In other words: without such support the packaging devices cannot reach the preset opening/piercing pressure, they can reach a higher preset opening/piercing pressure than can be reached without such support (the filter device "reduces" the pressure-bearing surface), and when configured in this way they can only reach the piercing pressure in the presence of the filter device. Advantageously, the containment means comprise at least one seal which ensures the leak-proof performance of the combustion chamber containing the pyrotechnic substance, breaking at a pressure high enough to guarantee a sufficient combustion of the pyrotechnic substance, sufficient for ignition, according to the operating time. Advantageously, the pyrotechnic substance is a loosely loaded tablet. Advantageously, the pyrotechnic substance is a loosely loaded tablet disposed about the gas generator ignition device. This contributes to an improved ignition quality of the pyrotechnic substance, making the gas generator more compact, in particular in an axial configuration. This axial compactness is particularly applicable to front seat, driver and passenger airbags. Advantageously, the support provided for the envelope by the filtering means allows the breakage of the non-supporting part of the envelope at the start of the operation of the gas generator, so that this breakage is controlled and repeatable, since the dimensions of the non-supporting part are determined by the dimensions of the filtering means used as support. Advantageously, the filter device provides support to the packing device in the form of a crown, so as to establish the non-supported part of the packing device in a cylind