Gas generator

Abstract

A gas generator is provided with: a housing; the ignition part is arranged in the shell; a gas generating agent accommodated in a combustion chamber in the housing and generating combustion gas by operation of the ignition unit; a discharge hole provided in the housing and discharging the combustion gas generated in the housing to the outside; and a filter disposed between the discharge hole and the gas generating agent, the filter being disposed so as to extend in the axial direction, and at least the outer peripheral portion of one end surface of the filter in the axial direction being connected to the inner wall surface of the housing so as to surround the periphery of the discharge hole. At least a part of the outer peripheral surface around the axis and a part of the whole periphery are used as the inflow part of the combustion gas, and the inflow part is communicated with the combustion chamber.

Description

Technical Field

[0001] The invention relates to a gas generator. Background Art

[0002] In the past, the following gas generators were widely used: a combustion chamber formed in a housing is filled with a gas generating agent, and the gas generating agent is burned by an igniter, thereby generating combustion gas and discharging the combustion gas to the outside through a gas discharge hole provided in the housing. In addition, in such a gas generator, a cylindrical filter is sometimes arranged between the combustion chamber and the gas discharge hole in order to cool the generated combustion gas and capture the residue.

[0003] Patent document 1 discloses a gas generator comprising: an ignition material configured to generate gas; a subassembly formed by a first component and a second component fixed by friction welding; a third component fixed to the first component or the second component by friction welding; and a cylindrical filter.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: U.S. Patent Application Publication No. 2019 / 001917 Summary of the invention

[0007] Problems to be solved by the invention

[0008] The above-mentioned gas generating device is configured to make the combustion gas flow from the inside to the outside of the cylindrical filter. The combustion gas passes through the filter, thereby filtering out the combustion residue, so the amount of combustion residue contained in the inlet side of the filter (hereinafter also referred to as the residue content) increases, and the residue content in the outlet side decreases. Therefore, in the configuration in which the combustion gas flows from the inner circumference to the outer circumference of the cylindrical filter, the residue content increases when flowing into the inner circumference narrower than the outer circumference, and the residue content decreases when passing through the wider outer circumference, so the filter cannot be used efficiently, and a technology for improving the utilization efficiency of the filter is sought.

[0009] The technology disclosed in the present invention has been accomplished in view of the above-mentioned actual situation, and an object of the present invention is to provide a technology capable of improving the utilization efficiency of a filter in a gas generator.

[0010] Solutions for solving problems

[0011] In order to solve the above problems, the technology disclosed in the present invention adopts the following structure. That is, the gas generator disclosed in the present invention has:

[0012] case;

[0013] An ignition unit, disposed in the housing;

[0014] A gas generating agent is contained in a combustion chamber in the housing and generates combustion gas through the operation of the ignition unit;

[0015] an exhaust hole provided in the housing to exhaust the combustion gas generated in the housing to the outside; and

[0016] A filter is disposed between the discharge hole and the gas generating agent,

[0017] The filter is configured to extend in the axial direction, and at least the outer peripheral portion of one end surface in the axial direction is connected to the inner wall surface of the shell in a manner surrounding the exhaust hole, and at least a portion of the outer peripheral surface existing around the axis and throughout the entire circumference is used as an inflow portion for the combustion gas, and the inflow portion is connected to the combustion chamber.

[0018] Alternatively, in the gas generator disclosed herein, the gas generator further comprises a partition wall member, the partition wall member dividing the combustion chamber containing the gas generating agent and the filter chamber in which the filter is arranged in the housing, and a connecting hole connecting the combustion chamber and the filter chamber is provided in a part of the partition wall member.

[0019] The partition wall member is connected to a second end surface on the opposite side of a first end surface connected to the inner wall surface of the case in the axial direction of the filter.

[0020] Alternatively, in the gas generator of the present disclosure, the housing may include: a cylindrical peripheral wall portion extending in the axial direction; a first wall portion blocking one end of the cylindrical peripheral wall portion; and a second wall portion blocking the other end.

[0021] The communication hole is formed in the first wall portion in a direction to discharge the combustion gas in a direction perpendicular to the first wall portion.

[0022] Alternatively, in the gas generator of the present disclosure, the housing may include: a cylindrical peripheral wall portion extending in the axial direction; a first wall portion having the discharge hole formed therein and blocking one end of the cylindrical peripheral wall portion; and a second wall portion blocking the other end.

[0023] A groove is provided on the inner surface of the first wall portion along the circumferential direction.

[0024] The communication hole is provided at a position where the combustion gas is discharged toward the groove portion.

[0025] Alternatively, in the gas generator of the present disclosure, the housing may include: a cylindrical peripheral wall portion extending in the axial direction; a first wall portion having the discharge hole formed therein and blocking one end of the cylindrical peripheral wall portion; and a second wall portion blocking the other end.

[0026] In the partition wall member, a portion not connected to the filter is formed to protrude toward the first wall portion of the case relative to a portion connected to the filter.

[0027] In the gas generator of the present disclosure, the housing may include a cylindrical peripheral wall portion.

[0028] The communication hole is formed in a direction to discharge the combustion gas toward the peripheral wall portion.

[0029] In the gas generator of the present disclosure, the filter may be formed in a cylindrical shape.

[0030] Alternatively, in the gas generator of the present disclosure, the housing may include: a cylindrical peripheral wall portion extending in the axial direction; a first wall portion blocking one end of the cylindrical peripheral wall portion; and a second wall portion blocking the other end.

[0031] One end surface of the filter in the axial direction is connected to the first wall portion, and the other end surface is connected to the second wall portion.

[0032] Beneficial Effects

[0033] According to the present disclosure, it is possible to improve the utilization efficiency of the filter in a gas generator including the filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is an axial cross-sectional view schematically showing the internal structure of the gas generator according to the first embodiment along the central axis.

[0035] Figure 2 It is a diagram showing the structure of a filter.

[0036] Figure 3 It is a top view showing an example of the layer structure of the filter.

[0037] Figure 4 yes Figure 3 AA section view.

[0038] Figure 5 It is an axial cross-sectional view of the gas generator according to the second embodiment.

[0039] Figure 6 It is a figure which shows the lower surface of a partition wall member.

[0040] Figure 7It is an axial cross-sectional view of the gas generator according to the third embodiment.

[0041] Figure 8 It is an axial cross-sectional view of a gas generator according to a fourth embodiment.

[0042] Fig. 9 It is an axial cross-sectional view of the gas generator according to the fifth embodiment.

[0043] Fig.10 It is a plan view showing the layer structure of the filter according to the fifth embodiment.

[0044] Fig.11 yes Fig.10 BB cross-sectional view.

[0045] Fig.12 It is an axial cross-sectional view of the gas generator according to the sixth embodiment.

[0046] Fig.13 This is an axial cross-sectional view schematically showing the internal structure of the gas generator according to the seventh embodiment along the central axis. DETAILED DESCRIPTION

[0047] Hereinafter, the gas generator of the embodiment of the present disclosure will be described with reference to the accompanying drawings. It should be noted that each structure and their combination in each embodiment is an example, and the addition, omission, replacement and other changes of the structure can be appropriately made within the scope of the main purpose of the present invention. The present invention is not limited by the embodiment, but only by the claims.

[0048] <First Embodiment>

[0049] Figure 1 FIG. 1 is an axial cross-sectional view schematically showing the internal structure of the gas generator 100 according to the first embodiment along the central axis C. Figure 1 As shown in FIG. 1 , a cross section obtained by cutting the gas generator 100 along the central axis C is sometimes referred to as a “longitudinal cross section” of the gas generator 100. In addition, a direction along the central axis C of the gas generator 100 is sometimes referred to as a “vertical direction” or “axial direction” of the gas generator 100, wherein one direction side ( Figure 1 The upper side of the direction is called the "upper side", and the other side ( Figure 1 These directions are examples for explaining the present embodiment, and the configuration of the gas generator 100 is not limited thereto. Figure 1 2 shows a state before the operation of the gas generator 100. The gas generator 100 is, for example, a gas generator for an airbag that supplies gas for inflating and deploying the airbag to the airbag.

[0050] [Overall composition]

[0051] like Figure 1 As shown, the gas generator 100 includes an ignition device 7, an inner cylinder member 5, a filter 6, a partition member 8, an explosive 110, a gas generating agent 120, and a housing 1 that accommodates these. The gas generator 100 of this embodiment is configured as a so-called single-stage gas generator that only has one ignition device. Not limited to this, the gas generator 100 may also be configured to have multiple ignition devices. The gas generator 100 is configured to: by operating the igniter 71 included in the ignition device 7, the gas generating agent 120 is burned, and the combustion gas as its combustion product is discharged from the gas discharge hole 11 formed in the housing 1. The following describes each structure of the gas generator 100.

[0052] [case]

[0053] The housing 1 is a member for accommodating an inner cylinder member 5, a filter 6, an ignition device 7, a partition member 8, an explosive 110, and a gas generator 120. The housing 1 includes an upper container 2 and a lower container 3 made of metal, each of which is formed into a generally cylindrical shape with a bottom. The upper container 2 and the lower container 3 are joined so that their open ends face each other, thereby forming a short cylindrical shape with both ends of the axial direction blocked. These upper container 2 and lower container 3 are containers 20 that define a combustion chamber 10 and are provided with a gas generator 120 and the like inside. In addition, the housing 1 includes an outer shell member 4 that is externally embedded in the gas discharge side of the container 20, which is the upper side in this example.

[0054] The upper container 2 has a cylindrical upper peripheral wall portion 21 and a top plate portion 22 that blocks the upper end of the upper peripheral wall portion 21, and an internal space is formed by these. The opening of the upper container 2 is formed at the lower end side of the internal space. The lower container 3 has a cylindrical lower peripheral wall portion 31 and a bottom plate portion 32 that blocks the lower end of the lower peripheral wall portion 31 and is fixed with the ignition device 7, and an internal space is formed by these. The opening of the lower container 3 is formed at the upper end of the internal space.

[0055] The joint portion 23 as the opening side end of the upper container 2 and the joint portion 33 as the opening side end of the lower container 3 are overlapped and joined by welding or the like, thereby forming a short cylindrical container 20 with both ends blocked in the axial direction. The upper peripheral wall portion 21 of the upper container 2 and the lower peripheral wall portion 31 of the lower container 3 constitute the peripheral wall portion 12 of the container 20. That is, the container 20 is constructed to include: a cylindrical peripheral wall portion 12; a top plate portion 22 provided on one end side of the peripheral wall portion 12; and a bottom plate portion 32 provided on the other end side of the peripheral wall portion 12. The top plate portion 22 is equivalent to the "first wall portion" of the present disclosure. In addition, the bottom plate portion 32 is equivalent to the "second wall portion" of the present disclosure.

[0056] The top plate portion 22 of the container 20 is provided with a discharge hole 25 that penetrates from the inside to the outside of the container 20 and discharges the combustion gas generated in the container 20 to the outside. The position of the discharge hole 25 is not particularly limited, but in the present embodiment, it is provided at the center when the top plate portion 22 is viewed from above. That is, the discharge hole 25 is formed concentrically with the peripheral wall portion 12.

[0057] The lower container 3 includes an ignition device 7 and an inner tube member 5, and the lower end of the inner tube member 5 is joined to the bottom plate 32 of the lower container 3. The inner tube member 5 is a cylindrical member extending from the bottom plate 32 to the top plate 22 so as to surround the ignition device 7.

[0058] The inner cylinder member 5 and the peripheral wall portion 12 are arranged in a concentric circle shape, and the inner space thereof is used as the ignition chamber 50, and the outer space is used as the combustion chamber 10. A substantially disk-shaped partition member 8 is provided on the upper side of the inner cylinder member 5 to divide the upper surface of the ignition chamber 50 and the combustion chamber 10. In addition, the partition member 8 divides the combustion chamber 10 on the lower side and the ignition chamber 50 and the filter chamber 60 on the upper side in the container 20. A plurality of connecting holes 81 are provided near the outer edge of the partition member 8 to connect the combustion chamber 10 and the filter chamber 60. The number and arrangement of the connecting holes 81 are not particularly limited, but in this embodiment, a plurality of connecting holes 81 are provided in the radial direction of the partition member 8, and a plurality of connecting holes 81 are provided at equal intervals along the circumferential direction of the partition member 8. In addition, the connecting holes 81 pass through along the axial direction of the housing 1, and are formed to discharge the combustion gas in a direction orthogonal to the direction in which the top plate portion 22 extends. That is, the connecting holes 81 of this embodiment are formed in the direction along the central axis C. Furthermore, when the top plate portion 22 is spherical, the exhaust direction of the combustion gas may be a direction along the central axis C or a direction perpendicular to the tangent line of the spherical surface (radial direction).

[0059] An ignition device 7 is arranged in the ignition chamber 50 inside the inner cylinder member 5, and an ignition powder 110 is filled around the ignition device 7. In addition, a gas generating agent 120 is filled in the combustion chamber 10 outside the inner cylinder member 5. Moreover, a plurality of connecting holes 52 are formed along the circumferential direction in the inner cylinder member 5, which connect the ignition chamber 50 as its inner space and the combustion chamber 10 as its outer space. The connecting holes 52 are blocked by a sealing tape (not shown) before the ignition device 7 is operated. When the ignition device 7 is operated, the sealing tape is cracked due to the pressure of the combustion gas, and the ignition chamber 50 is connected with the combustion chamber 10. It should be noted that the connecting holes 52 only need to connect the inside and the outside of the ignition chamber 50 at least when the ignition device 7 is operated, and they do not need to be blocked by the sealing tape.

[0060] A filter 6 is arranged in the filter chamber 60 in the container 20. The shape of the filter 6 is not particularly limited, but it can also be, for example, cylindrical or columnar. It should be noted that the filter 6 of the present embodiment is cylindrical. In addition, the filter 6 of the present embodiment is arranged in the center of the filter chamber 60 in a manner covering the discharge hole 25, but is not limited to this, as long as it is arranged between the discharge hole 25 and the gas generating agent 120, that is, the position where the combustion gas passes. In other words, the discharge hole 25 is formed in the projection area of ​​the cross-sectional shape of the filter 6 orthogonal to the central axis C.

[0061] The upper surface 61 of the filter 6 is in contact with the top plate 22 of the container 20, and the lower surface 63 is in contact with the upper surface of the partition member 8, and is sandwiched by the top plate 22 and the partition member 8. A recess 82 having substantially the same shape as the lower portion of the filter 6 is provided on the upper surface of the partition member 8, and the lower portion of the filter 6 is positioned by being embedded in the recess 82.

[0062] The container 20 is filled with a pressurized inert gas (hereinafter, also referred to as pressurized gas), and the discharge hole 25 is blocked by the rupture plate 26. In addition, the airtightness of the opening portion of the bottom plate portion 32 equipped with the ignition device 7 is maintained by arranging a cup-shaped sealing member 53 in a manner covering the periphery of the ignition device 7. The sealing member 53 is made of metal, for example, and is joined to the bottom plate portion 32 by welding or the like. The sealing member 53 has rigidity to withstand the pressure of the inert gas, and is configured to be ruptured by the operation of the ignition device 7. Here, the inert gas can include argon, helium, or a mixture thereof. The gas generator 100 of this embodiment is a hybrid type that discharges pressurized gas and combustion gas when operating.

[0063] The outer shell member 4 mounted on the gas discharge side of the container 20 has: a cylindrical peripheral wall portion 41; a top plate portion 42 blocking the upper end of the peripheral wall portion 41; and a flange portion 43 extending radially from the lower end of the peripheral wall portion 41. The outer shell member 4 is externally fitted to the upper part of the container 20 and joined to the outer surface of the peripheral wall portion 12. In the state of being joined to the container 20 in this way, the outer shell member 4 forms a discharge side space 44 that serves as a discharge path for the combustion gas between the top plate portion 22 of the container 20. A plurality of gas discharge holes 11 that communicate the discharge side space 44 with the external space are formed in the peripheral wall portion 41 of the outer shell member 4 in a circumferential direction.

[0064] [Ignition device]

[0065] like Figure 1As shown, the ignition device 7 includes an igniter 71 and a mounting member 72, which are fixed to the bottom plate portion 32 of the lower container 3. The ignition device 7 is equivalent to the "ignition unit" of the present disclosure. The igniter 71 has: a metal cup body 711 for accommodating the explosive; and a pair of current-carrying pins 712 and 713 for receiving the supply of current from the outside. The igniter 71 works by supplying an ignition current to the pair of current-carrying pins 712 and 713, thereby causing the explosive to burn and discharging its combustion products to the outside of the cup body 711.

[0066] The mounting member 72 is a member that is clamped between the igniter 71 and the bottom plate portion 32 to fix the igniter 71 relative to the bottom plate portion 32. The mounting member 72 includes a resin that covers the lower portion of the igniter 71 and forms a connector insertion space into which a connector (not shown) can be inserted. The connector supplies power from an external power source to a pair of power supply pins 712 and 713. It should be noted that the fixing of the igniter 71 to the bottom plate portion 32 and the relationship between the mounting member 72 and the bottom plate portion 32 are not limited to Figure 1 , known techniques may be used.

[0067] [Filter]

[0068] Figure 2 : is a diagram showing the structure of the filter 6. The filter 6 is a cylindrical member formed of a metal material, that is, a member having fine holes that have the function of filtering the residue in the combustion gas and cooling the combustion gas by allowing the combustion gas to pass through. The filter 6 is configured to extend in the axial direction, and at least the outer peripheral portion of the first end surface (upper surface) 61 in the axial direction is connected to the top plate portion 22 in a manner surrounding the discharge hole 25. At least a portion of the outer peripheral surface 62 that exists around the axis and the portion throughout the entire circumference is used as the inflow portion of the combustion gas, and the inflow portion is connected to the combustion chamber 10 during operation. Therefore, when the combustion gas is discharged from the combustion chamber 10 during operation, the combustion gas flows in from the outer peripheral surface 62 of the filter 6 and is discharged from the center of the upper surface 61 to the discharge hole 25. At this time, the upper surface 61 of the filter 6 abuts against the top plate 22, and the lower surface (second end surface) 63 on the opposite side abuts against the recessed portion 82 of the partition member 8, thereby preventing the combustion gas from flowing between the upper surface 61 and the top plate 22 and between the lower surface 63 and the partition member 8, i.e., the so-called "short circuit". It should be noted that a sealing unit may be arranged between the upper surface 61 and the top plate 22, between the lower surface 63 and the partition member 8, or between the two.

[0069] The filter 6 of this example is formed by overlapping annular metal plates having many holes in the radial direction. For example, the filter 6 may be formed by overlapping cylindrical metal plates in concentric circles or by overlapping the metal plates in radial directions by winding them into a spiral shape when viewed from above. Alternatively, the filter 6 may be formed by overlapping porous metal plates formed into a circular plate in the axial direction. Examples of porous metal plates that serve as the material of the filter 6 include expanded metal, lath metal, punched metal, metal mesh, etc. It should be noted that Figure 2 In the figure, reference numeral 62 indicates the outer peripheral surface of the filter 6. A plurality of holes are formed in the filter 6, so that the combustion gas of the gas generating agent 120 arranged in the combustion chamber 10 can pass through the filter 6. The filter 6 filters the combustion gas by capturing the combustion residues included in the combustion gas. In addition, in addition to the function of filtering the above-mentioned combustion gas, the filter 6 also has the function of cooling the combustion gas by taking away the heat of the combustion gas when the combustion gas passes through the filter 6. It should be noted that as the filter 6, in addition to this, it can also be a compression formed filter such as Japanese Patent Laid-Open No. 10-119705, and a winding filter in which a metal wire is wound in multiple layers such as Japanese Patent Laid-Open No. 2005-193138.

[0070] Figure 3 is a plan view showing an example of the layer structure of the filter 6, Figure 4 yes Figure 3 AA cross-sectional view of the filter 6. The filter 6 can be constructed to have a plurality of layers in the radial direction, and the specifications of each layer are different. For example, the filter 6 can be constructed to have a higher density (reduce the opening ratio) of the inner layer compared to the outer layer. Figure 3 , Figure 4 The filter 6 includes three layers of an inner portion 65 , a middle portion 66 , and an outer portion 67 . The density of the middle portion 66 is lower than that of the inner portion 65 , and the density of the outer portion 67 is lower than that of the middle portion 66 .

[0071] [Gunpowder]

[0072] As the primer 110, in addition to the known black powder, a gas generator having good ignition performance and a combustion temperature higher than that of the gas generator 120 can be used. The combustion temperature of the primer 110 can be set in the range of 1700° C. to 3000° C. As such a primer 110, for example, a known primer containing nitroguanidine (34% by weight) and strontium nitrate (56% by weight) can be used. In addition, the primer 110 can be in various shapes such as granules, pellets, cylinders, and discs.

[0073] [Gas generating agent]

[0074] As the gas generator 120, a gas generator with a relatively low combustion temperature can be used. The combustion temperature of the gas generator 120 can be set within a range of 1000°C to 1700°C. As such a gas generator 120, for example, a known gas generator including guanidine nitrate (41% by weight), basic copper nitrate (49% by weight), a binder, and an additive can be used. In addition, the gas generator 120 can be in various shapes, such as granular, pellet, cylindrical, and disc-like.

[0075] [action]

[0076] Next, the operation of the gas generator 100 according to the first embodiment will be described. Figure 1 , while explaining. When the sensor (not shown) senses the impact, the ignition current is supplied to a pair of energized pins 712 and 713, and the igniter 71 works. That is, the detonator contained in the cup body 711 of the igniter 71 burns, and the flame, high-temperature gas, etc. as its combustion products cause the cup body 711 to rupture and be discharged to the outside of the cup body 711. As a result, the explosive 110 contained in the ignition chamber 50 burns to generate combustion gas. The combustion gas of the explosive 110 breaks through the sealing tape blocking the connecting hole 52 and is discharged from the connecting hole 52 to the outside of the ignition chamber 50. Then, the combustion gas of the explosive 110 contacts the gas generator 120, and the gas generator 120 is ignited. The gas generator 120 burns, thereby generating high-temperature / high-pressure combustion gas in the combustion chamber 10. In this way, when combustion gas begins to be generated and the pressure in the container 20 increases, the rupture plate 26 blocking the discharge hole 25 ruptures, and the combustion gas is discharged from the discharge hole 25 together with the pressurized gas in the container 20. At this time, the combustion gas passes through the filter 6, whereby the combustion gas is cooled and the combustion residue is captured. The pressurized gas and the combustion gas that pass through the filter 6 and are discharged from the discharge hole 25 to the discharge side space 44 contact the top plate portion 42 of the outer shell member 4 and deflect radially toward the shell 1, and are discharged to the outside of the shell 1 from the gas discharge hole 11. Then, after the pressurized gas and the combustion gas are discharged to the outside of the shell 1, they flow into the airbag (not shown). As a result, the airbag expands, thereby forming a buffer between the occupant and the hard structure, protecting the occupant from impact.

[0077] [Function / Effect]

[0078] In the gas generator 100 of the present embodiment, at least the outer peripheral portion of one end surface 61 of the filter 6 is connected to the inner wall surface of the top plate portion 22 in a manner surrounding the discharge hole 25, and the outer peripheral surface 62 is connected to the combustion chamber 10. As a result, the combustion gas passes through the outer peripheral surface 62 of the filter 6 at the initial time of inflow when the amount of combustion residue contained (hereinafter, also referred to as the residue content) is large, is filtered, and passes through the inner portion while the residue content decreases. In other words, as the combustion gas enters the inner side from the inflow portion formed on the outer peripheral surface 62 of the filter 6 as a whole in the circumferential direction, the residue content is filtered and reduced, the combustion gas temperature is also reduced, and the radial cross-sectional area of ​​the filter contacted by the combustion gas is gradually reduced. That is, a contact area of ​​the filter corresponding to the residue content and the gas temperature is provided. As a result, the utilization efficiency of the filter 6 can be improved, and the performance of the gas generator 100 can be improved. Furthermore, by improving the utilization efficiency of the filter 6 , it is possible to achieve the same filter performance as in the related art with a smaller filter 6 , and thus the gas generator 100 can be miniaturized.

[0079] In gas generator 100 of the present embodiment, filter 6 may be configured to include a plurality of layers in the radial direction, with the inner layer having a higher density than the outer layer. This can further improve the utilization efficiency of filter 6.

[0080] Furthermore, in the gas generator 100 of the present embodiment, the communicating hole 81 of the partition member 8 is formed in a direction that discharges the combustion gas in a direction orthogonal to the extending direction of the top plate portion 22. Thus, by configuring the combustion gas generated in the combustion chamber 10 to first contact the top plate portion 22, large residues or residues with high adhesion are attached to the top plate portion 22 and then flow into the filter 6, the utilization efficiency of the filter 6 is further improved.

[0081] Furthermore, in the gas generator 100 of the present embodiment, the upper surface 61 of the filter 6 is in contact with the top plate 22, and the lower surface 63 of the filter 6 is in contact with the recessed portion 82 of the partition member 8. Thus, the combustion gas can be prevented from flowing between the upper surface 61 and the top plate 22 and between the lower surface 63 and the partition member 8, i.e., the so-called "short circuit", and the utilization efficiency of the filter 6 can be improved. It should be noted that in the first embodiment, as long as the short circuit between the upper surface 61 of the filter 6 and the top plate 22 can be prevented, a gap can be formed between the lower surface 63 and the partition member 8.

[0082] <Second Embodiment>

[0083] Figure 5 is an axial cross-sectional view of a gas generator 200 according to the second embodiment, Figure 6 2 is a diagram showing the lower surface of the partition wall member 8. Figure 5, the state before the operation of the gas generator 200 is shown. Compared with the first embodiment described above, the present embodiment is different in the configuration of the top plate portion 22A, and the other configurations are the same. Therefore, the same reference numerals are given to the same elements as the first embodiment, and re-examination thereof is omitted.

[0084] like Figure 5 , Figure 6 As shown, the upper container 2 of this embodiment has a cylindrical upper peripheral wall portion 21 and a top plate portion 22A that blocks the upper end of the upper peripheral wall portion 21, and a groove portion 222 along the circumferential direction is provided on the lower surface 221 side of the top plate portion 22A. In addition, the connecting hole 81 of the partition member 8 is provided at a position where the combustion gas is discharged to the groove portion 222. The connecting hole 81 of this embodiment is formed in the axial direction directly below the groove portion 222 to discharge the combustion gas to the groove portion 222.

[0085] Thus, according to the present embodiment, the combustion gas generated in the combustion chamber 10 is discharged toward the groove portion 222, and after being retained in the groove portion 222, flows into the filter 6. Therefore, large residues or highly sticky residues in the combustion gas are removed in the groove portion 222, and the utilization efficiency of the filter 6 can be improved. It is also possible to provide concavities and convexities on the surface of the groove portion 222 to increase the contact area with the combustion gas.

[0086] <Third Embodiment>

[0087] Figure 7 FIG. 2 is an axial cross-sectional view of a gas generator 300 according to the third embodiment. Figure 7 , the state before the operation of the gas generator 300 is shown. Compared with the first embodiment described above, the present embodiment is different in the structure of the partition member 8A, and the other structures are the same. Therefore, the same reference numerals are given to the same elements as the first embodiment, and the re-examination is omitted.

[0088] like Figure 7 As shown, the partition wall member 8A of this embodiment is formed such that, relative to the central portion 83 connected to the filter 6, the outer portion 84 not connected to the filter 6 protrudes toward the top plate portion 22 of the housing 1. Figure 7 In the example of , the outer portion 84 is formed into a conical shape in such a way that it is located on the upper side as it moves from the radial inner side to the outer side. That is, the combustion chamber 10 is configured to extend toward the filter chamber 60. Therefore, in the gas generator 300 of the present embodiment, the lower peripheral wall portion 31 of the lower container 3 extends upward in matching with the partition member 8A, and compared with the first embodiment, the joint portion between the upper container 2 and the lower container 3 is formed on the side of the top plate portion 22 relative to the partition member 8A.

[0089] As described above, according to the present embodiment, the combustion chamber 10 is formed larger than that of the gas generator 100 of the first embodiment, so that the filling amount of the gas generating agent 120 and the pressurized gas can be increased, and the performance of the gas generator 300 can be improved.

[0090] <Fourth Embodiment>

[0091] Figure 8 FIG. 4 is an axial cross-sectional view of a gas generator 400 according to a fourth embodiment. Figure 8 , the state before the operation of the gas generator 400 is shown. Compared with the third embodiment described above, the present embodiment is different in the structure of the partition member 8B, and the other structures are the same. Therefore, the same reference numerals are given to the same elements as the third embodiment, and re-examination is omitted.

[0092] like Figure 8 As shown, the partition wall member 8B in the present embodiment is formed into a conical shape in such a manner that the outer portion 85 not connected to the filter 6 is located at the lower side as the radial inside goes to the outer side relative to the central portion 83 connected to the filter 6. In addition, the connecting hole 81B of the partition wall member 8B is formed so as to be located at the outer side (the peripheral wall portion 12 side) as the filter chamber 60 side goes from the combustion chamber 10 side. That is, the connecting hole 81B in the present embodiment is formed in a direction to discharge the combustion gas toward the peripheral wall portion 12.

[0093] Thus, according to the present embodiment, the combustion gas generated in the combustion chamber 10 is discharged toward the peripheral wall portion 12, and flows into the filter 6 after contacting the peripheral wall portion 12. Therefore, large residues or highly sticky residues in the combustion gas adhere to the peripheral wall portion 12 and are removed, and the utilization efficiency of the filter 6 can be improved.

[0094] <Fifth Embodiment>

[0095] Fig. 9 is an axial cross-sectional view of a gas generator 500 according to a fifth embodiment, Fig.10 is a plan view showing the layer structure of a filter 6A according to the fifth embodiment. Fig.11 yes Fig.10 BB cross-sectional view. Fig. 9 , the state before the operation of the gas generator 500 is shown. Compared with the first embodiment described above, the present embodiment is different in the structure of the filter 6A, and the other structures are the same. Therefore, the same reference numerals are given to the same elements as the first embodiment, and the re-examination is omitted.

[0096] like Fig. 9As shown, the filter 6A of the present embodiment is formed into a cylindrical shape. An axial end face (upper surface) 61A of the filter 6 is connected to the top plate portion 22 in a manner surrounding the discharge hole 25, and the other end face (lower surface) 63A is connected to the partition member 8. That is, the filter 6A has a through hole in the radial central portion from the upper surface 61A toward the lower surface 63A, and the discharge hole 25 is formed in the area facing the through hole. In addition, the filter 6A can be constructed to have multiple layers in the radial direction, so that the specifications of each layer are different. For example, the filter 6A has two layers, an inner part 66A and an outer part 67A, so that the density of the outer part 67A is lower than that of the inner part 66A. It should be noted that the number of layers is not limited to this and can be set arbitrarily.

[0097] Thus, according to the present embodiment, the combustion gas generated in the combustion chamber 10 passes from the outside to the inside of the filter 6A. Therefore, the utilization efficiency of the filter 6 can be improved. It should be noted that in the present embodiment, the structure other than the filter 6A is the same as that of the first embodiment, but it is not limited thereto, and the structure may also be the same as that of the second to fourth embodiments.

[0098] <Sixth Embodiment>

[0099] Fig.12 FIG. 2 is an axial cross-sectional view of a gas generator 600 according to the sixth embodiment. Fig.12 , the state before the operation of the gas generator 600 is shown. Compared with the fifth embodiment described above, the present embodiment is different in that the pyrotechnic type does not use pressurized gas, and the other structures are the same. Therefore, the same reference numerals are given to the same elements as the fifth embodiment, and the re-examination is omitted.

[0100] In this embodiment, the container 20 is not filled with pressurized gas, and the lower end of the discharge hole 25 is blocked by the sealing tape 27. That is, the sealing tape 27 is arranged in the internal space of the filter 6A, and the sealing tape 27 does not interfere with the filter 6A.

[0101] When the igniter 71 works and the explosive 110 and the gas generator 120 burn to generate combustion gas, the sealing band blocking the connecting hole 52 breaks, and the combustion gas passes through the filter 6A and is discharged from the exhaust hole 25, and is discharged from the gas exhaust hole 11 to the outside of the shell 1 through the exhaust side space 44.

[0102] As described above, according to the present embodiment, the combustion gas generated in the combustion chamber 10 is configured to pass from the outside to the inside of the filter 6A. Therefore, the utilization efficiency of the filter 6 can be improved.

[0103] <Seventh Embodiment>

[0104] Fig.131 is an axial cross-sectional view schematically showing the internal structure of the gas generator 700 according to the seventh embodiment along the central axis C. It should be noted that the same reference numerals are used for the same elements as those in the first embodiment, and some descriptions are omitted. In addition, the gas generator 700 according to the seventh embodiment does not use pressurized gas.

[0105] like Fig.13 As shown, the gas generator 700 includes an ignition device 7, a filter 6B, a gas generating agent 120, and a housing 1 for accommodating them. The gas generator 700 of this embodiment is configured as a so-called single-stage gas generator having only one ignition device. The present invention is not limited thereto, and the gas generator 700 may also be configured to have a plurality of ignition devices.

[0106] The housing 1 is a member for accommodating the filter 6B, the ignition device 7, and the gas generating agent 120. The housing 1 includes an upper container 2 and a lower container 3 made of metal, each of which is formed into a generally cylindrical shape with a bottom. The upper container 2 and the lower container 3 are joined so that the open ends of each other face each other, thereby forming a short cylindrical shape with both ends of the axial direction blocked. These upper container 2 and lower container 3 are containers 20 that define the combustion chamber 10A and have the gas generating agent 120 and the like arranged inside. In addition, the housing 1 includes a shell member 4 that is externally embedded on the gas discharge side of the container 20, in this example, the upper side.

[0107] A discharge hole 25 is provided in the top plate portion 22 of the container 20 . The discharge hole 25 penetrates from the inside to the outside of the container 20 and discharges the combustion gas generated in the container 20 to the outside.

[0108] A cylindrical filter 6B is provided in the container 20, and the internal space of the container 20 is divided into an inner space and an outer space, and the outer space is set as the combustion chamber 10A. The filter 6B has a through hole formed in the radial center from the upper surface 61B to the lower surface 63B, and a discharge hole 25 is formed in a manner facing the area (internal space) formed by the through hole.

[0109] An ignition device 7 is disposed in the combustion chamber 10A in the lower container 3 , and a gas generating agent 120 is filled around the ignition device 7 .

[0110] The filter 6B is a cylindrical member formed of a metal material. Its upper surface 61B is in contact with the top plate 22 so as to surround the periphery of the discharge hole 25 , and its lower surface 63B is in contact with the bottom plate 32 and is sandwiched between the top plate 22 and the bottom plate 32 .

[0111] A sealing tape 27 is provided at the center of the inner surface of the top plate 22 to cover the discharge hole 25 and block the discharge hole 25. That is, the sealing tape 27 is arranged in the internal space of the filter 6B without interfering with the filter 6B.

[0112] When the igniter 71 is operated, the detonator contained in the cup body 711 of the igniter 71 burns, and the flame, high-temperature gas, etc. as the combustion products are discharged to the outside of the cup body 711. As a result, the gas generating agent 120 contained in the combustion chamber 10A burns to generate high-temperature / high-pressure combustion gas. As a result, the pressure in the container 20 increases, the sealing tape 27 blocking the discharge hole 25 is cracked, and the combustion gas is discharged from the discharge hole 25 through the filter 6B. At this time, the combustion gas passes through the filter 6B, whereby the combustion gas is cooled and the combustion residue is captured. The pressurized gas and the combustion gas discharged from the discharge hole 25 to the discharge side space 44 contact the top plate portion 42 of the outer shell member 4 and deflect in the radial direction of the shell 1, and are discharged to the outside of the shell 1 from the gas discharge hole 11. Then, after the pressurized gas and the combustion gas are discharged to the outside of the shell 1, they flow into the airbag (not shown). As a result, the airbag expands, thereby forming a buffer between the occupant and the hard structure, protecting the occupant from impact.

[0113] In the gas generator 700 of the present embodiment, the configuration is such that the one end surface 61B of the filter 6B is connected to the inner wall surface of the top plate portion 22 in a manner surrounding the periphery of the discharge hole 25, and the outer peripheral surface 62B is connected to the combustion chamber 10. As a result, the combustion gas passes through the outer peripheral surface 62B of the filter 6B at the initial time point of inflow when the amount of residue contained is large, is filtered, and passes toward the inner peripheral surface 68 of the filter 6B while the amount of residue contained is reduced. That is, as the combustion gas enters the inner peripheral surface 68 from the inflow portion formed in the circumferential direction of the outer peripheral surface 62B of the filter 6B as a whole, the amount of residue contained is filtered and reduced, the combustion gas temperature is also reduced, and the radial cross-sectional area of ​​the filter that the combustion gas contacts is gradually reduced. That is, a contact area of ​​the filter corresponding to the amount of residue contained and the gas temperature is provided. Therefore, the utilization efficiency of the filter 6B can be improved, and the performance of the gas generator 700 can be improved.

[0114] In addition, in the gas generator 700 of the present embodiment, the configuration is such that the upper surface 61B of the filter 6B abuts against the top plate 22, and the lower surface 63B of the filter 6B abuts against the bottom plate 32. This can prevent the combustion gas from flowing between the upper surface 61 and the top plate 22 and between the lower surface 63 and the bottom plate 32, i.e., the so-called "short circuit", and can improve the utilization efficiency of the filter 6. It should be noted that in Fig. 9 , Fig.12 , Fig.13 In the gas generator shown, as long as the short circuit between the upper surface 61A, 61B of the filter and the top plate portion 22 is prevented, the through hole of the filter does not need to penetrate through the lower surface 63A, 63B, and a component can be sandwiched between the lower surface 63A, 63B and the partition member 8 or the bottom plate portion 32, so that the filter can be configured to be separated from the partition member 8 or the bottom plate portion 32.

[0115] <Others>

[0116] As mentioned above, although the preferred embodiment of this disclosure is described, each aspect disclosed in this specification can also be combined with other arbitrary features disclosed in this specification.

[0117] Description of Reference Numerals

[0118] 1: Shell;

[0119] 10: Combustion chamber;

[0120] 100~700: Gas generator;

[0121] 10A: Combustion chamber;

[0122] 11: Gas discharge hole;

[0123] 110: passing gunpowder;

[0124] 12: peripheral wall;

[0125] 120: gas generating agent;

[0126] 2: Upper container;

[0127] 20: container;

[0128] 21: upper peripheral wall portion;

[0129] 22: top plate;

[0130] 221: lower surface;

[0131] 222: groove;

[0132] 22A: top plate;

[0133] 23: joint;

[0134] 25: discharge hole;

[0135] 26: rupture plate;

[0136] 27: Sealing tape;

[0137] 3: Lower container;

[0138] 31: lower peripheral wall portion;

[0139] 32: bottom plate;

[0140] 33: joint;

[0141] 4: Shell components;

[0142] 41: peripheral wall;

[0143] 42: top plate;

[0144] 43: flange portion;

[0145] 44: discharge side space;

[0146] 5: Inner cylinder component;

[0147] 50: Fire transmission room;

[0148] 52: connecting hole;

[0149] 6, 6A, 6B: Filter;

[0150] 60: filter chamber;

[0151] 7: Ignition device;

[0152] 8: Bulkhead components;

[0153] 81, 81B: communicating holes;

[0154] 82: Concave.

Claims

1. A gas generator comprising: case; An ignition unit, disposed in the housing; A gas generating agent is contained in a combustion chamber in the housing and generates combustion gas through the operation of the ignition unit; an exhaust hole provided in the housing to exhaust the combustion gas generated in the housing to the outside; and A filter is disposed between the discharge hole and the gas generating agent, The filter is configured to extend in the axial direction, and at least the outer peripheral portion of one end surface in the axial direction is connected to the inner wall surface of the shell in a manner surrounding the exhaust hole, and at least a portion of the outer peripheral surface existing around the axis and throughout the entire circumference is used as an inflow portion for the combustion gas, and the inflow portion is connected to the combustion chamber.

2. The gas generator according to claim 1, wherein: The gas generator further includes a partition member that divides the combustion chamber containing the gas generating agent and a filter chamber in which the filter is arranged in the housing, and a connecting hole connecting the combustion chamber and the filter chamber is provided in a portion of the partition member. The partition wall member is connected to a second end surface on the opposite side of a first end surface connected to the inner wall surface of the case in the axial direction of the filter.

3. The gas generator according to claim 2, wherein: The housing includes: a cylindrical peripheral wall portion extending in the axial direction; a first wall portion blocking one end of the cylindrical peripheral wall portion; and a second wall portion blocking the other end. The communication hole is formed in the first wall portion in a direction to discharge the combustion gas in a direction perpendicular to the first wall portion.

4. The gas generator according to claim 2, wherein: The housing comprises: a cylindrical peripheral wall portion extending in the axial direction; a first wall portion having the discharge hole formed therein and blocking one end of the cylindrical peripheral wall portion; and a second wall portion blocking the other end. A groove is provided on the inner surface of the first wall portion along the circumferential direction. The communication hole is provided at a position where the combustion gas is discharged toward the groove portion.

5. The gas generator according to claim 2, wherein: The housing comprises: a cylindrical peripheral wall portion extending in the axial direction; a first wall portion having the discharge hole formed therein and blocking one end of the cylindrical peripheral wall portion; and a second wall portion blocking the other end. In the partition wall member, a portion not connected to the filter is formed to protrude toward the first wall portion of the case relative to a portion connected to the filter.

6. The gas generator according to claim 2, wherein: The housing includes a cylindrical peripheral wall portion. The communication hole is formed in a direction to discharge the combustion gas toward the peripheral wall portion.

7. The gas generator according to any one of claims 2 to 6, wherein: The filter is formed in a cylindrical shape.

8. The gas generator according to claim 1, wherein: The housing comprises: a cylindrical peripheral wall portion extending in the axial direction; a first wall portion blocking one end of the cylindrical peripheral wall portion; and a second wall portion blocking the other end. One end surface of the filter in the axial direction is connected to the first wall portion, and the other end surface is connected to the second wall portion.

Images