Gas generator
By incorporating axial gaps and a closed-body design in the gas generator, the issues of environmental tolerance and activation reliability of the gas generator are resolved, achieving efficient and reliable gas supply and meeting high safety standards.
Patent Information
- Application Number
- CN202580025263.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-04-02
- Filing Date
- 2025-03-26
- Publication Date
- 2026-11-03
AI Technical Summary
Existing gas generators are not resistant enough to environmental influences such as moisture ingress or corrosion, and the gas supply during activation is not reliable enough, making it difficult to meet the requirements of long-term use and high safety standards.
An axial gap is set on the ignition tube to connect the ignition space and the combustion chamber, and the ignition gas flows through the axial gap to ignite the fuel. The design of the enclosure and diffuser ensures reliable gas flow and sealing. The igniter is fixed by a coating casting to enhance its resistance to environmental impact.
This invention enables the gas generator to reliably provide gas drive protection after activation, improves its resistance to environmental influences, ensures the reliability and efficiency of gas generation, and reduces manufacturing difficulty and cost.
Smart Images
Figure CN123036227A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a gas generator, particularly a gas generator for a protective device in a vehicle, the gas generator comprising: a housing having a canister-shaped diffuser and a closure, the diffuser having a bottom section, wherein the diffuser and the closure are axially opposed to each other, and a combustion chamber is present inside the housing; an ignition tube surrounded by the combustion chamber, the ignition tube having an ignition space filled with a pyrotechnic enhancement charge within its inner boundary and being fixed to the housing via a base; and an igniter fixed to the base, the igniter being axially adjacent to the ignition space. Background Technology
[0002] Gas generators used in vehicle protective devices, such as those that prop up engine hoods, tighten seat belts, move cushions, etc., or inflate airbags.
[0003] To meet high safety standards, gas generators must be able to function normally for a single use over a period of many years. In other words, gas generators must withstand high requirements in terms of resistance to environmental influences such as moisture ingress or corrosion during this period.
[0004] In addition, the gas generator must be constructed such that when the gas generator is activated, it reliably provides gas at all times for driving the protection device or for priming the protection device. Summary of the Invention
[0005] The objective of this invention is to provide a gas generator that provides gas reliably after activation.
[0006] The task is accomplished by a gas generator according to the preamble of claim 1, wherein the ignition tube has at least one elongated slit in the axial direction, and the ignition space is connected to the combustion chamber via the slit. In the context of this invention, an elongated slit in the axial direction is a slit having a maximum extension dimension in the axial direction. Hereinafter, the elongated slit in the axial direction will be referred to as an axial slit.
[0007] According to the present invention, axial slots are recognized to be opened or kept open more reliably than circular through-holes. Furthermore, axial slots, by virtue of their elongated axial extension, facilitate the flow of ignition gases generated during the activation of the enhanced charge in the ignition space through the at least one axial slot to the fuel disposed in the combustion chamber and to effectively ignite the fuel.
[0008] Here, an axial gap can be provided at the end of the ignition space facing the base and extending at least 10% of the axial height of the ignition space, particularly wherein the gap begins from the end of the ignition tube near the base. This allows the ignition gas to reliably flow into the axially lower region of the combustion chamber, i.e., the region away from the bottom section of the diffuser, and there ignites the fuel disposed in the lower region. In this way, gas for driving or priming the protective device, formed during fuel combustion, is provided particularly reliably after activation of the gas generator.
[0009] Additionally or alternatively, the ignition tube may have at least two or at least three axial slits, which are arranged, particularly in the circumferential direction, at uniformly spaced intervals from each other. This configuration has the advantage that ignition gas flows simultaneously through multiple slits into the combustion chamber and towards the fuel, igniting the fuel at multiple locations.
[0010] According to one embodiment, particularly the preamble of claim 1, the ignition tube has an open first axial end facing the base and an opposite open second axial end, the second axial end being axially opposed to the bottom section of the diffuser. Because the ignition tube is constructed as a tube open on both sides, it can be manufactured with particularly low cost, even if it is formed from high-strength steel. In particular, deep drawing is not required as a processing step.
[0011] Here, in the inactive state of the gas generator, the second axial end can be sealed by clamping the ignition tube between the diffuser and the base, and in the active state of the gas generator, the bottom section of the diffuser can bulge out to expose the second axial end. In this way, the ignition space is effectively sealed before and during the ignition of the booster charge, and opened after the booster charge and fuel are ignited.
[0012] According to one embodiment, the bottom section of the diffuser, in the inactive state of the gas generator, directly abuts against and particularly seals the second axial end of the ignition tube. Therefore, the second axial end of the ignition tube is directly sealed by the housing, and the gas generator is constructed with exceptional efficiency.
[0013] According to an alternative embodiment, the gas generator has a seal that, in the inactive state of the gas generator, is axially arranged between the second axial end of the ignition tube and the bottom section of the diffuser, thereby sealingly closing the second axial end of the ignition tube. In this way, the second axial end of the ignition tube is closed via the seal and thus indirectly through the housing.
[0014] Furthermore, it can be specified that the enclosure is canister-shaped and has a bottom section and a peripheral wall section, the peripheral wall section extending axially from the bottom section of the enclosure and toward the bottom section of the diffuser, and the peripheral wall section radially outwards defining the combustion chamber. Here, the bottom section of the diffuser, in the inactive state of the gas generator, abuts against the first end of the peripheral wall section of the enclosure. In particular, the peripheral wall section of the enclosure may have a smaller diameter at the first end compared to the second end, which is adjacent to the bottom section of the enclosure. Thus, the outer shell and the combustion chamber are constructed particularly effectively and efficiently.
[0015] Here, the gas generator can be configured such that, after the igniter is activated, the booster charge burns in the ignition space of the ignition tube, wherein the particles and ignition gas formed during combustion flow into the combustion chamber via the at least one axial gap, particularly in a direction that at least partially points axially towards the bottom section of the enclosure, and the particles and ignition gas ignite the fuel disposed in the combustion chamber. Here, during fuel combustion, a charging gas is formed, which causes the outer casing to expand axially such that a circumferentially surrounding discharge gap is formed between the bottom section of the diffuser and the first end of the peripheral wall section of the enclosure, and the discharged gas flows into a circumferentially surrounding diffusion chamber formed radially between the peripheral wall section of the enclosure and the peripheral wall section of the diffuser. Here, the charging gas flows radially out of the gas generator via an outlet hole in the peripheral wall section of the diffuser. Therefore, the gas generator has a particularly advantageous gas flow upon activation, which reliably ensures effective gas generation.
[0016] In one embodiment, the igniter is embedded in the base by encapsulation casting or encapsulation injection and is thus securely and cost-effectively secured.
[0017] Here, the ignition tube can be sealed relative to the base during encapsulation casting or encapsulation injection, thereby effectively sealing the ignition space in the inactive state of the gas generator and connecting it to the combustion chamber essentially only via the at least one axial gap.
[0018] In another embodiment, the base extends through the central opening in the enclosure, thereby giving the outer shell particularly high strength.
[0019] Here, the base can be configured to receive the igniter plug, thus allowing the gas generator to be constructed with exceptional efficiency.
[0020] Furthermore, it can be specified that the enclosure, viewed from the outside, has a central recess, into which the base extends from the interior of the gas generator. Preferably, the recess is completely covered by the base facing outwards. In this way, the gas generator is constructed in a particularly compact manner and exhibits high resistance to environmental influences such as moisture ingress.
[0021] Here, the recess may be can-shaped and have a bottom with a recess and / or a bulge, which is, for example, completely filled or surrounded by a base. This has the advantage that the recess is reliably sealed by the base. Furthermore, the base is effectively secured to the bottom in this manner. Attached Figure Description
[0022] Other advantages and features will become apparent from the following description and from the accompanying drawings, which illustrate:
[0023] Figure 1 A schematic cross-sectional view shows the gas generator according to the invention in its inactive state.
[0024] Figure 2 A schematic cross-sectional view shows the active state. Figure 1 The gas generator in the middle,
[0025] Figure 3 Shown in perspective Figure 1 The ignition tube of the gas generator in the middle, and
[0026] Figure 4 A schematic cross-sectional view shows a gas generator according to another embodiment in an inactive state, based on the invention. Detailed Implementation
[0027] The following detailed description, taken in conjunction with the accompanying drawings (in which the same reference numerals indicate the same elements), is intended to illustrate different embodiments of the disclosed subject matter and should not be construed as individual embodiments. Each embodiment described in this disclosure is used as an example or illustration only and should not be construed as being preferred or advantageous over other embodiments.
[0028] All features disclosed below with respect to embodiments and / or drawings can be combined individually or in any sub-combination with features of various aspects of this disclosure, including features of preferred embodiments, provided that the resulting combination of features is reasonable to those skilled in the art.
[0029] Figure 1 The image shows a gas generator 10, which has a housing 12 assembled from a can-shaped diffuser 14 and a can-shaped enclosure 16.
[0030] The gas generator 10 is particularly designed to drive or activate protective devices in a vehicle.
[0031] The diffuser 14 has a bottom section 18 and a generally cylindrical peripheral wall section 20 that extends in the axial direction A.
[0032] The diffuser 14 has a plurality of, for example, twelve outflow holes 22 in the peripheral wall section 20, which are evenly distributed on the periphery of the diffuser 14 and arranged at an axial height.
[0033] The enclosure 16 has a bottom section 24 and a peripheral wall section 26, which extends away from the bottom section 24 in the opposite axial direction A and toward a first end 28 of the peripheral wall section 26, and is arranged radially inward relative to the peripheral wall section 20 of the diffuser 14.
[0034] Here, the peripheral wall section 26 of the enclosure 16 has a first diameter d at its first end 28 and a second diameter D at its axially opposite second end 30, which is adjacent to the bottom section 24.
[0035] In this embodiment, the first diameter d is smaller than the second diameter D, thereby the enclosure 16 bulges radially near the bottom section 24 of the enclosure 16 and tapers towards the bottom section 18 of the diffuser 14 in the opposite axial direction A.
[0036] The peripheral wall section 26 of the enclosure 16 abuts against the peripheral wall section 20 of the diffuser 14 at its second end 30 on the radially inner side, and is fixedly connected to the peripheral wall section by means of a surrounding weld 32.
[0037] In addition, Figure 1 In the inactive state of the gas generator 10 shown, the peripheral wall section 26 of the enclosure 16 extends to the bottom section 18 of the diffuser 14, such that the first end 28 of the peripheral wall section 26 abuts against the bottom section 18 of the diffuser 14 on the end side, especially in a circumferential manner against the bottom section of the diffuser.
[0038] Thus, a diffusion chamber 34 is formed in the radial direction between the peripheral wall section 26 of the enclosure 16 and the peripheral wall section 20 of the diffuser 14, the diffusion chamber surrounding in the circumferential direction and adjacent to the outflow hole 22 on the radially outer side.
[0039] Therefore, the can-shaped diffuser 14 and the can-shaped enclosure 16 are arranged in opposite nesting arrangements, such that the inner sides of the bottom sections 18 and 24 are opposite to each other, and the interior 36 of the outer shell 12 is bounded.
[0040] In this regard, the closed body 16 has a central recess 38 with a central opening 40.
[0041] The recess 38 extends into the interior 36 of the outer casing 12 or extends in the opposite axial direction A toward the bottom section 18 of the diffuser 14.
[0042] Furthermore, the recessed portion 38 is can-shaped with a bottom 42, the bottom having an annular bulge 44.
[0043] As an addition to or alternative to the annular bulge 44, the bottom 42 of the can-shaped recess 38 may have an annular recess in another embodiment.
[0044] In addition, an ignition tube 46 and an igniter 48 are arranged inside the housing 12, and the ignition tube and the igniter are fixed to the enclosure 16 via a base 50.
[0045] Here, the base 50 has an inner section 52 arranged in the interior 36 and an outer section 54 arranged in the recess 38, the inner section and the outer section being connected to each other through a central opening 40.
[0046] The outer section 54 completely covers the recess 38 and forms a receiving geometry 56 for the igniter plug (not shown) in the recess, into which the contact pin 58 of the igniter 48 extends.
[0047] The igniter 48 is embedded in the internal section 52, for example, by encapsulation casting or encapsulation injection, and is thus shaped-locked to the base 50.
[0048] In addition, the internal section 52 completely fills the bulge 44, thereby providing a particularly stable connection between the base 50 and the enclosure 16.
[0049] In this regard, the ignition tube 46 has an open first axial end 60 facing the bottom section 24 of the enclosure 16 and an open second axial end 62 facing the bottom section 18 of the diffuser 14.
[0050] The ignition tube 46 is cylindrical, especially round.
[0051] The ignition tube 46 is sealed to the internal section 52 at the first axial end 60.
[0052] For example, when the igniter 48 and the base 50 are encapsulated and cast or injected together, the internal section 52 can be integrally cast or injected onto the ignition tube 46.
[0053] In an alternative embodiment, during assembly, the ignition tube 46 is inserted into the inner section 52 in the axial direction A.
[0054] For this purpose, the ignition tube 46 may have a chamfered portion 64 on the radially inner side at the first axial end 60 (see...). Figure 3 ( ), so that it can be inserted.
[0055] The ignition tube 46 defines the ignition space 66 on its inner side, and the igniter 48 is axially adjacent to the ignition space.
[0056] With the gas generator 10 in an inactive state, the ignition tube 46 is held between the diffuser 14 and the base 50 in the axial direction A. In the illustrated embodiment, the bottom section 18 of the diffuser 14 rests directly against the ignition tube 46 at its end and closes the second axial end 62, preferably sealing the second axial end.
[0057] In an alternative implementation (see...) Figure 4 In the gas generator 10, a seal 68 is arranged in the axial direction A between a second axial end 62 and a bottom section 18 of a diffuser 14 to seal the second axial end 62 in the inactive state of the gas generator 10.
[0058] Preferably, the seal 68 is fixed to the bottom section 18 of the diffuser 14 opposite to the second axial end 62 of the ignition tube 46.
[0059] The seal 68 is, for example, a disc-shaped component, such as a silicone disc.
[0060] Figure 4 The embodiment of the gas generator 10 shown is similar to the one with the seal 68. Figure 1 The gas generator 10 shown is constructed in the same manner as the embodiment shown.
[0061] In all embodiments, the ignition tube 46 is radially surrounded by a combustion chamber 70, which is also bounded radially and axially by a closure 16 and by a bottom section 18 of a diffuser 14.
[0062] The combustion chamber 70 is at least partially filled with fuel 72, said fuel in Figure 1 The diagram is schematically shown through multiple plates, and the fuel produces a charging gas when it burns, which is a gas provided for driving the protective device or charging the protective device.
[0063] The ignition space 66 is at least partially filled with a pyrotechnic enhancement charge 74, wherein the pyrotechnic enhancement charge is in Figure 1 The image is schematically shown through multiple plates, and the pyrotechnic enhancement charge is configured to ignite the fuel 72 in the combustion chamber 70 after it is ignited by the igniter 48.
[0064] For this purpose, the ignition tube 46 has at least one axial slot 76 that connects the ignition space 66 to the combustion chamber 70, and when the gas generator 10 is activated, particles and ignition gases formed during the combustion of the enhanced charge 74 flow through the axial slot into the combustion chamber 70.
[0065] In this embodiment, the ignition tube 46 has three axial slots 76 (see...) Figure 3 The axial gaps are arranged at equal intervals relative to each other in the circumferential direction, that is, the three axial gaps 76 are arranged at an angle of 120° relative to each other.
[0066] Here, the axial gap 76 has a width B and an axial length L in the circumferential direction, the axial length being greater than the width B, and in particular at least twice the width.
[0067] exist Figure 3 In the embodiment shown, the axial length L is approximately 50% of the total axial length G of the ignition tube 46.
[0068] In principle, the axial length L can account for any large proportion of the total axial length G, preferably at least 25%.
[0069] Furthermore, the axial slot 76 extends in the axial direction A to a first axial end 60 or to an end 78 that is close to or adjacent to the base 50. Thus, the axial slot 76 is arranged in the axial half of the ignition tube 46 facing the base 50.
[0070] In principle, the axial gap 76 can be arranged at any axial height in the ignition tube 46.
[0071] Preferably, the axial gap 76 is arranged adjacent to the axial end 80 of the ignition space 66, which is adjacent to the base 50.
[0072] Additionally or alternatively, in a preferred embodiment, the axial gap 76 extends over at least 10% of the axial height H of the ignition space 66 (see [link]). Figure 1 ).
[0073] In order to provide the charging gas for driving or charging the protective device, the igniter 48 is first activated and thereby ignites the booster charge 74.
[0074] During the combustion of the enhanced charge 74, particles and ignition gases are formed in the ignition space 66 enclosed by the bottom section 18 of the diffuser 14.
[0075] Here, the pressure in the ignition space 66 increases, causing particles and ignition gases to flow through the axial gap 76 into the combustion chamber 70 and ignite the fuel 72 there. The flow direction is... Figure 2 It is indicated by an arrow.
[0076] Here, particles and ignition gas flow through the axial gap 76 in a direction that is at least partially directed in the axial direction A toward the bottom section 24 of the enclosure 16, thereby also reliably igniting the fuel 72, which is disposed near the bottom section 24 of the enclosure 16.
[0077] When fuel 72 burns, an inflatable gas is formed in combustion chamber 70. The pressure in combustion chamber 70 is increased so strongly by the inflatable gas that the bottom section 18 of diffuser 14 bulges outward or extends away from enclosure 16 in the opposite axial direction A.
[0078] Figure 2 The state shown in the diagram, in which the gas generator 10 or the housing 12 expands axially, is referred to as the active state of the gas generator 10.
[0079] With the gas generator 10 in the activated state, the ignition tube 46 is no longer clamped between the diffuser 14 and the base 50; instead, the second axial end 62 is released, and thus the ignition space 66 opens axially at that location. This can be applied in a similar manner. Figure 4 The embodiment shown has a seal 68.
[0080] Furthermore, when the gas generator 10 is activated, the outer casing 12 expands to such an extent that a circumferentially surrounding discharge gap 82 is formed between the bottom section 18 of the diffuser 14 and the first end 28 of the peripheral wall section 26 of the enclosure 16 (see [link]). Figure 2 The filling gas flows radially from the combustion chamber 70 to the diffusion chamber 34 through the discharge gap.
[0081] Finally, the filling gas flows out of the diffuser 34 from the gas generator 10 in the radial direction through the outlet hole 22 and flows toward the corresponding protective device.
[0082] The gas generator 10 is formed in this way, which provides gas particularly reliably after activation and can be manufactured cost-effectively.
Claims
1. A gas generator (10), particularly a gas generator for protective devices in vehicles, said gas generator comprising: The outer shell (12) has a can-shaped diffuser (14) and a closure (16), the diffuser having a bottom section (18), wherein the diffuser (14) and the closure (16) are opposite to each other in the axial direction (A), and a combustion chamber (70) is located inside (36) of the outer shell (12). An ignition tube (46) surrounded by the combustion chamber (70), the ignition tube having an ignition space (66) filled with a pyrotechnic enhancement charge (74) within its inner boundary and fixed to the outer casing (12) via a base (50); and An igniter (48) is fixed on the base (50) and is axially adjacent to the ignition space (66). The ignition tube (46) is characterized in that it has at least one elongated slit (76) in the axial direction (A), and the ignition space (66) is connected to the combustion chamber (70) via the slit.
2. The gas generator (10) according to claim 1, characterized in that, The axial gap (76) is provided at the end (80) of the ignition space (66) facing the base (50), and the axial gap extends at least 10% of the axial height (H) of the ignition space (66), and in particular, the gap (76) begins from the end (78) of the ignition tube (46) near the base (50).
3. The gas generator (10) according to claim 1 or 2, characterized in that, The ignition tube (46) has at least two or at least three axial slots (76), which are arranged at a uniform distance from each other, especially in the circumferential direction.
4. The gas generator (10) according to any one of the preceding claims, especially the preamble of claim 1, is characterized in that, The ignition tube (46) has an open first axial end (60) facing the base (50) and an open second axial end (62) opposite to the bottom section (18) of the diffuser (14) in the axial direction (A).
5. The gas generator (10) according to claim 4, characterized in that, In the inactive state of the gas generator (10), the second axial end (62) is closed by clamping the ignition tube (46) between the diffuser (14) and the base (50), and in the active state of the gas generator (10), the bottom section (18) of the diffuser (14) bulges so that the second axial end (62) is exposed.
6. The gas generator (10) according to claim 4 or 5, characterized in that, The bottom section (18) of the diffuser (14) is directly attached to the second axial end (62) of the ignition tube (46) in the inactive state of the gas generator (10) and in particular, the second axial end is sealed.
7. The gas generator (10) according to claim 4 or 5, characterized in that, The gas generator (10) has a seal (68) which is arranged in the axial direction (A) between the second axial end (62) of the ignition tube (46) and the bottom section (18) of the diffuser (14) in the inactive state of the gas generator (10), thereby sealing the second axial end (62) of the ignition tube (46).
8. The gas generator (10) according to any one of the preceding claims, characterized in that, The enclosure (16) is constructed in the shape of a can and has a bottom section (24) and a peripheral wall section (26), the peripheral wall section being axially (A) away from the bottom section (24) of the enclosure (16) and extending toward the bottom section (18) of the diffuser (14), and the peripheral wall section radially outwardly defining the combustion chamber (70), wherein the bottom section (18) of the diffuser (14) abuts against the first end (28) of the peripheral wall section (26) of the enclosure (16) in the inactive state of the gas generator (10), and in particular, wherein the peripheral wall section (26) of the enclosure (16) has a smaller diameter (d) at the first end (28) than at the second end (30), the second end being adjacent to the bottom section (24) of the enclosure (16).
9. The gas generator (10) according to claim 8, characterized in that, The gas generator (10) is configured such that, after the igniter (48) is activated, the enhanced charge (74) burns in the ignition space (66) of the ignition tube (46), wherein the particles and ignition gas formed during combustion flow into the combustion chamber (70) via the at least one axial slit (76), particularly in a direction that at least partially points in the axial direction (A) toward the bottom section (24) of the enclosure (16), and the particles and ignition gas ignite the fuel (72) disposed in the combustion chamber (70), wherein a charge gas is formed during the combustion of the fuel (72), the charge gas... The body expands the outer shell (12) in the axial direction such that a discharge gap (82) is formed in the circumferential direction between the bottom section (18) of the diffuser (14) and the first end (28) of the peripheral wall section (26) of the enclosure (16), and the discharged gas flows into a diffusion chamber (34) in the circumferential direction, which is formed in the radial direction between the peripheral wall section (26) of the enclosure (16) and the peripheral wall section (20) of the diffuser (14), wherein the filling gas flows out of the gas generator (10) in the radial direction through an outlet hole in the peripheral wall section (20) of the diffuser (14).
10. The gas generator (10) according to any one of the preceding claims, characterized in that, The igniter (48) is embedded in the base (50) by encapsulation casting or encapsulation injection.
11. The gas generator (10) according to claim 10, characterized in that, The ignition tube (46) is sealed relative to the base (50) during encapsulation casting or encapsulation injection.
12. The gas generator (10) according to any one of the preceding claims, characterized in that, The base (50) extends through the central opening (40) in the enclosure (16).
13. The gas generator (10) according to claim 12, characterized in that, The base (50) forms a receiving geometry (56) for the igniter plug.
14. The gas generator (10) according to any one of the preceding claims, characterized in that, The enclosure (16), when viewed from the outside, has a central recess (38), into which the base (50) extends from the interior (36) of the gas generator (10) into the recess, preferably wherein, The recess (38) is completely covered by the base (50) facing outward.
15. The gas generator (10) according to claim 14, characterized in that, The recess (38) is can-shaped and has a bottom (42) with a recess and / or a bulge (44) which is filled or surrounded by the base (50).