Gas generator and gas discharge method of gas generator

Abstract

A gas generator is provided with: an igniter; a gas generating agent which is combusted by the operation of the igniter, thereby generating combustion gas; a housing in which the igniter and the gas generating agent are accommodated; a gas discharge hole penetrating the inside and outside of the housing; and a metal sealing member which is formed in a sheet shape, is attached to the inner surface of the housing, covers the opening of the gas discharge hole on the inner surface side of the housing before the igniter is operated, blocks the gas discharge hole, and opens the gas discharge hole by cracking under the pressure of the combustion gas generated by the operation of the igniter. The gas discharge hole has a chamfered region obtained by removing the corner of the opening on the inner surface side of the housing over the entire circumference.

Description

Technical Field

[0001] The present invention relates to a gas generator and a method for discharging gas in the gas generator. Background Art

[0002] Conventionally, a gas generator is widely used in which an igniter and a gas generating agent are arranged in a housing, the igniter is operated to burn the gas generating agent, and the combustion gas is discharged to the outside through one or more gas discharge holes formed in the housing.

[0003] The gas generator is configured such that the gas discharge port is blocked by a blocking member such as a sealing tape, thereby maintaining the interior of the housing airtight before operation, and when operating, the blocking member is ruptured by the pressure of the combustion gas, thereby opening the gas discharge hole. In this regard, a technique for blocking the gas discharge hole with a moisture-proof sealing tape that can prevent the gas generating agent from absorbing moisture is known (for example, Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 10-217899 Summary of the invention

[0007] Problems to be solved by the invention

[0008] Furthermore, the combustion gas generated in the housing and reaching the gas discharge hole may contain residues generated by combustion (combustion residues). In the gas generator, it is desirable to prevent the combustion residues from being discharged to the outside of the gas generator as much as possible.

[0009] An object of the technology disclosed in the present disclosure is to reduce the amount of combustion residues discharged to the outside of 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 configuration. That is, the gist of the technology disclosed in the present invention is as follows.

[0012] [1]

[0013] The technology disclosed herein is a gas generator having:

[0014] Igniter;

[0015] a gas generating agent that burns through the operation of the igniter to generate combustion gas;

[0016] a housing, accommodating the igniter and the gas generating agent therein;

[0017] a gas discharge hole penetrating inside and outside of the shell; and

[0018] a metal seal member formed in a sheet shape and mounted on the inner surface of the housing, covering the opening of the inner surface side of the housing of the gas discharge hole before the igniter is operated, thereby blocking the gas discharge hole, and being ruptured by the pressure of the combustion gas generated by the operation of the igniter, thereby opening the gas discharge hole,

[0019] The gas discharge hole has a chamfered area obtained by removing a corner of an opening portion on the inner surface side of the housing over the entire circumference.

[0020] [2]

[0021] Alternatively, in the gas generator described in [1],

[0022] The chamfered area is formed so as to decrease in diameter as it becomes farther away from the opening portion on the inner surface side of the housing in the thickness direction of the housing.

[0023] 〔3〕

[0024] Alternatively, in the gas generator described in [1] or [2],

[0025] The inner wall surface of the chamfered area is formed in a straight line or a curved line in a cross section along the thickness direction of the housing.

[0026] [4]

[0027] Alternatively, in the gas generator described in any one of [1] to [3],

[0028] The gas discharge hole has a straight region connected to the chamfered region and extending with a constant inner diameter.

[0029] 〔5〕

[0030] Alternatively, in the gas generator described in any one of [1] to [4],

[0031] The sealing member comprises: a base material layer made of aluminum; and an adhesive layer, which is disposed on one side of the base material layer and is bonded to the inner surface of the housing.

[0032] The thickness of the base material layer is 50 [μm] or more and 200 [μm] or less.

[0033] [6]

[0034] In the gas generator described in [5], the tensile strength of the seal member measured in accordance with JIS Z0237 may be 100 [N] / 20 [mm] or more and 200 [N] / 20 [mm] or less.

[0035] 〔7〕

[0036] Alternatively, in the gas generator described in [5] or [6], the sealing member further includes an adhesive layer, the adhesive layer being provided on the other side of the base material layer and having adhesive properties.

[0037] 〔8〕

[0038] Alternatively, in the gas generator described in any one of [1] to [7],

[0039] The gas generator is configured such that when the sealing member is ruptured, at least a portion of the sealing member remains in the gas discharge hole.

[0040] 〔9〕

[0041] Alternatively, in the gas generator described in any one of [1] to [8],

[0042] The gas generator is configured such that, by rupturing the sealant, a minimum flow path cross-sectional area of ​​the combustion gas flow path formed in the gas discharge hole is made smaller than a minimum cross-sectional area of ​​the gas discharge hole.

[0043] 〔10〕

[0044] The technology disclosed in the present invention is a gas exhaust method of a gas generator, comprising the following steps:

[0045] The step of preparing a housing of the gas generator, the housing accommodating an igniter and a gas generating agent that burns to generate combustion gas when the igniter is operated, and the housing is formed with a gas discharge hole that penetrates inside and outside the housing, the gas discharge hole having a chamfered area obtained by removing corners of an opening portion on the inner surface side of the housing over the entire circumference;

[0046] A step of attaching a sheet-shaped metal seal to the inner surface of the housing to cover the opening of the gas discharge hole on the inner surface side of the housing, thereby blocking the gas discharge hole;

[0047] The step of assembling the gas generator;

[0048] The step of operating the igniter; and

[0049] The step of using the pressure of the combustion gas generated by the operation of the igniter to press the seal against the inner wall surface of the chamfered area, so that an area of ​​the seal that is closer to the inside than the abutting area against the inner wall surface of the chamfered area is cracked, thereby cracking the seal in a manner that at least a portion of the seal remains in the gas discharge hole.

[0050]

[11]

[0051] Alternatively, in the gas exhaust method described in

[10] ,

[0052] In the step of preparing the housing, the chamfered area is formed in the gas discharge hole in such a manner that the diameter thereof decreases as the opening on the inner surface side of the housing is away from the opening in the thickness direction of the housing.

[0053] In the step of rupturing the sealing member, the sealing member is ruptured by bending the sealing member so as to be along the inner wall surface of the chamfered region.

[0054]

[12]

[0055] Alternatively, in the gas exhaust method described in

[10] or

[11] ,

[0056] In the step of preparing the housing, the inner wall surface of the chamfered area is formed in a linear or curved shape in a cross section along a thickness direction of the housing.

[0057] 〔13〕

[0058] Alternatively, in the gas exhaust method described in any one of

[10] to

[12] ,

[0059] In the step of preparing the housing, the gas discharge hole is formed in a straight cylindrical region opened on the outer surface of the housing and extending with a fixed inner diameter,

[0060] In the step of rupturing the sealing member, the sealing member is ruptured by bending the sealing member so that at least a portion of the sealing member reaches the straight region.

[0061]

[14]

[0062] Alternatively, in the gas exhaust method described in any one of

[10] to

[13] ,

[0063] In the step of rupturing the sealing member, the sealing member is ruptured by bending the sealing member so that a minimum flow path cross-sectional area of ​​the combustion gas flow path formed in the gas discharge hole becomes smaller than a minimum cross-sectional area of ​​the gas discharge hole.

[0064] 〔15〕

[0065] Alternatively, in the gas exhaust method described in any one of

[10] to

[14] ,

[0066] In the step of blocking the gas discharge hole, the gas discharge hole is blocked by the sealing member including an aluminum base material layer and an adhesive layer provided on one surface of the base material layer and bonded to the inner surface of the housing.

[0067]

[16]

[0068] Alternatively, in the gas exhaust method described in any one of

[10] to

[15] ,

[0069] A plurality of gas discharge holes are formed in the shell,

[0070] In the step of assembling the gas generator, a cylindrical filter is disposed inside the housing so as to form an annular space between the filter and the inner surface of the housing.

[0071] In the step of rupturing the seal, the combustion gas generated by the operation of the igniter and passing through the filter is introduced into the annular space so that the pressure in the annular space is made uniform, and then pressure is applied to the seal.

[0072]

[17]

[0073] Alternatively, in the gas exhaust method described in any one of

[10] to

[16] ,

[0074] In the step of rupturing the sealing member, the sealing member is stretched by the pressure of the combustion gas, and the sealing member is ruptured by bending the sealing member while at least a portion of the sealing member remains in the gas discharge hole.

[0075] Beneficial Effects

[0076] According to the technology of the present disclosure, the amount of combustion residue discharged to the outside of the gas generator can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Figure 1 It is a longitudinal sectional view showing a state before operation of the gas generator according to the embodiment.

[0078] Figure 2 It is an enlarged cross-sectional view of the vicinity of the gas discharge hole of the gas generator according to the embodiment.

[0079] Figure 3 It is a cross-sectional view for explaining the structure of the seal band of the gas generator according to the embodiment.

[0080] Figure 4 This is a flowchart of a gas exhaust method of a gas generator according to an embodiment.

[0081] Figure 5This is a cross-sectional view (1) for explaining a preparation step of a housing according to an embodiment.

[0082] Figure 6 This is a cross-sectional view (2) for explaining a preparation step of a casing according to an embodiment.

[0083] Figure 7 This is a cross-sectional view (1) for explaining a cleavage step of a seal member according to an embodiment.

[0084] Figure 8 This is a cross-sectional view (2) for explaining the cleavage step of the seal material according to the embodiment.

[0085] Fig. 9 It is an enlarged cross-sectional view of the vicinity of the gas discharge hole of the gas generator according to Modification 1 of the embodiment.

[0086] Fig.10 This is a cross-sectional view for explaining the structure of a seal band of a gas generator according to Modification 2 of the embodiment.

[0087] Fig.11 This is a table showing the results of the combustion residue amount measurement test.

[0088] Fig.12 This is a table showing the results of the chamfer ratio evaluation test. DETAILED DESCRIPTION

[0089] Hereinafter, the gas generator of the embodiment of the present disclosure will be described with reference to the accompanying drawings. In the embodiment described below, a scheme of applying the technology of the present disclosure to a gas generator (inflator) for an airbag will be described. However, the use of the technology of the present disclosure is not limited thereto, and for example, it can be applied to a gas generator for a seat belt retractor. Each structure and combination thereof in each embodiment is an example, and the structure can be appropriately added, omitted, replaced, and otherwise changed without departing from the scope of the main purpose of the present invention. The present disclosure is not limited to the embodiment, but only to the claims. It should be noted that in this specification, "chamfer" refers to removing the corner of a component, including C chamfer and R chamfer.

[0090] Figure 1 1 is a longitudinal sectional view showing a state of the gas generator 100 according to the embodiment before operation. Figure 1The middle figure shows a cross section along the central axis of the housing 1 indicated by the reference numeral CA1. The gas generator 100 of the present embodiment is configured as a so-called dual-type gas generator having two igniters. However, the technology disclosed in the present invention is not limited thereto. That is, the gas generator disclosed in the present invention only needs to have one or more igniters, and may be a so-called single-type gas generator having only one igniter, or may be a gas generator having three or more igniters.

[0091] [Overall composition]

[0092] like Figure 1 As shown, the gas generator 100 includes a first ignition device 4, a first inner cylinder member 5, an explosive 6, a second ignition device 7, a second inner cylinder member 8, a filter 9, a first gas generating agent 110, a second gas generating agent 120, a shell 1 for accommodating them, a plurality of gas discharge holes 13 penetrating the inside and outside of the shell 1, and a sealing band S1 for blocking the plurality of gas discharge holes 13. The gas generator 100 is configured such that the first gas generating agent 110 is burned by operating the first igniter 41 of the first ignition device 4, and the second gas generating agent 120 is burned by operating the second igniter 71 of the second ignition device 7, and the combustion gas as their combustion products is discharged from the plurality of gas discharge holes 13 formed in the shell 1. Here, the direction along the central axis CA1 of the shell 1 is defined as the up-down direction of the gas generator 100, and the upper shell side (i.e., Figure 1 The upper side of the gas generator 100 is set as the upper side of the gas generator 100, and the lower shell side (that is, Figure 1 The lower side in the figure is set as the lower side of the gas generator 100. The following describes the various components of the gas generator 100. It should be noted that in this specification, for convenience, the ignition device operation included in the ignition device is sometimes expressed as "ignition device operation" or "gas generator operation".

[0093] [case]

[0094] In the outer shell 1, an upper shell 2 and a lower shell 3 made of metal, each formed into a roughly cylindrical shape with a bottom, are joined with their open ends facing each other, thereby forming a short-sized cylindrical shape including a cylindrical peripheral wall portion shown by the figure mark 11 and the axial ends of the peripheral wall portion 11 are blocked. Figure 1 The central axis CA1 is the central axis of the peripheral wall portion 11 .

[0095] The upper housing 2 has a cylindrical upper peripheral wall portion 21 and a top plate portion 22 blocking the upper end of the upper peripheral wall portion 21. A joint portion 23 extending radially outward is connected to the lower end of the upper peripheral wall portion 21. The lower housing 3 has a cylindrical lower peripheral wall portion 31 and a bottom plate portion 32 blocking the lower end of the lower peripheral wall portion 31. A joint portion 33 extending radially outward is connected to the upper end of the lower peripheral wall portion 31. The bottom plate portion 32 is formed with a first assembly hole 32a for assembling the first ignition device 4 on the bottom plate portion 32 and a second assembly hole 32b for assembling the second ignition device 7 on the bottom plate portion 32.

[0096] The joint portion 23 of the upper shell 2 and the joint portion 33 of the lower shell 3 are joined by laser welding or the like after being superimposed, thereby forming a short cylindrical shell 1 with both ends blocked in the axial direction. The upper peripheral wall portion 21 of the upper shell 2 and the lower peripheral wall portion 31 of the lower shell 3 form a cylindrical peripheral wall portion 11 connecting the top plate portion 22 and the bottom plate portion 32. That is, the shell 1 is configured to include: a cylindrical peripheral wall portion 11; a top plate portion 22, which is provided on one end side of the peripheral wall portion 11; and a bottom plate portion 32, which is provided on the other end side in a manner opposite to the top plate portion 22. The first combustion chamber 10 is defined by these peripheral wall portions 11, the top plate portion 22, the bottom plate portion 32 and the second inner cylinder member 8 described later. The first ignition device 4, the first inner cylinder member 5, the transfer powder 6, the filter 9 and the first gas generating agent 110 are arranged in the first combustion chamber 10.

[0097] [Ignition device]

[0098] like Figure 1As shown, the first ignition device 4 is fixed to the first assembly hole 32a formed in the bottom plate portion 32 of the lower shell 3. The first ignition device 4 is provided with a first igniter 41. The second ignition device 7 is fixed to the second assembly hole 32b formed in the bottom plate portion 32 of the lower shell 3. In addition, the second ignition device 7 is provided with a second igniter 71. The first igniter 41 and the second igniter 71 each contain a primer inside thereof, and operate by supplying an ignition current, thereby causing the primer to burn and discharging its combustion products to the outside. The first igniter 41 and the second igniter 71 are an example of an "igniter" of the present disclosure. The first ignition device 4 and the second ignition device 7 operate independently of each other. When the second ignition device 7 operates, the second ignition device 7 operates at the same time as the first ignition device 4 or at a specified timing after the first ignition device 4 operates. By the combustion of the first gas generating agent 110 realized by the operation of the first ignition device 4 and the combustion of the second gas generating agent 120 realized by the operation of the second ignition device 7, the gas generator 100 can release a large amount of combustion gas to the outside with various output profiles compared to the so-called single-stage gas generator. It should be noted that the second ignition device 7 does not always work. For example, the gas generator 100 can operate only the first ignition device 4 and not the second ignition device 7 when the impact is weak based on the impact sensed by the sensor. In addition, for example, when the impact is strong, the first ignition device 4 and the second ignition device 7 can be operated at the same time.

[0099] [Inner cylinder member]

[0100] The first inner cylinder member 5 is a bottomed cylindrical member extending from the bottom plate portion 32 toward the top plate portion 22, and includes a cylindrical surrounding wall portion 51 and a cover wall portion 52 that blocks one end of the surrounding wall portion 51. The first inner cylinder member 5 is assembled to the bottom plate portion 32 by inserting or pressing the first ignition device 4 into the other end of the surrounding wall portion 51. Figure 1 As shown, the first ignition device 4 is surrounded by a surrounding wall portion 51, thereby forming a ignition chamber 53 between the first inner cylinder member 5 and the first ignition device 4. The ignition chamber 53 contains an ignition powder 6 that burns when the first ignition device 4 is operated. In addition, a plurality of communication holes h1 that connect the internal space of the first inner cylinder member 5 (i.e., the ignition chamber 53) with the external space are formed in the surrounding wall portion 51 of the first inner cylinder member 5. In the state before the first ignition device 4 is operated, the communication holes h1 can also be blocked by a sealing tape.

[0101] The second inner cylinder member 8 is a bottomed cylindrical member extending from the bottom plate portion 32 toward the top plate portion 22, and includes a cylindrical surrounding wall portion 81 and a cover wall portion 82 that blocks one end of the surrounding wall portion 81. The second inner cylinder member 8 is assembled to the bottom plate portion 32 by embedding or pressing the second ignition device 7 into the other end of the surrounding wall portion 81. Figure 1 As shown, a second combustion chamber 20 is formed inside the second inner cylinder member 8, and the second combustion chamber 20 is provided with a second ignition device 7 and a second gas generating agent 120 that burns by the operation of the second ignition device 7. In addition, a plurality of communication holes h2 that communicate the internal space of the second inner cylinder member 8 (i.e., the second combustion chamber 20) with the external space (i.e., the first combustion chamber 10) are formed in the surrounding wall portion 81 of the second inner cylinder member 8. Before the second ignition device 7 is operated, the communication holes h2 are blocked by the sealing tape.

[0102] [Filter]

[0103] like Figure 1 As shown, the filter 9 is formed into a cylindrical shape, and the filter 9 surrounds the first gas generating agent 110, and is arranged in the first combustion chamber 10 in such a manner that the gas discharge holes 13 are located outside the filter 9 in the radial direction of the filter 9. That is, the filter 9 is arranged between the first gas generating agent 110 and the plurality of gas discharge holes 13 in such a manner as to surround the first gas generating agent 110. Thus, as Figure 1 As shown, an annular space 12 is formed between the outer peripheral surface of the filter 9 and the inner surface 11a of the shell 1 (the inner peripheral surface of the peripheral wall portion 11). The upper end surface of the filter 9 is supported by the top plate portion 22 of the upper shell 2, and the lower end surface is supported by the bottom plate portion 32 of the lower shell 3. The filter 9 can be formed, for example, by forming a metal wire or a porous plate into a cylindrical shape. When the combustion gas of the first gas generator 110 and the second gas generator 120 passes through the filter 9, the filter 9 cools the combustion gas by taking away the heat of the combustion gas. In addition, in addition to the function of cooling the combustion gas, the filter 9 also has the function of filtering the combustion gas by capturing the combustion residue contained in the combustion gas. It should be noted that the "filter" disclosed in the present invention only needs to have at least one of the functions of cooling the combustion gas and capturing the combustion residue.

[0104] [Gunpowder]

[0105] As the primer 6, in addition to the known black powder, a gas generating agent having good ignition performance and a higher combustion temperature than the first gas generating agent 110 can be used. The combustion temperature of the primer 6 can be set in the range of 1700° C. to 3000° C. As such a primer 6, for example, a known primer containing nitroguanidine (34% by weight) and strontium nitrate (56% by weight) can be used. In addition, the primer 6 can be in various shapes such as granular, pellet, cylindrical, and disc shapes.

[0106] [Gas generating agent]

[0107] The first gas generator 110 burns by the operation of the first igniter 41, thereby generating combustion gas. The second gas generator 120 burns by the operation of the second igniter 71, thereby generating combustion gas. For the first gas generator 110 and the second gas generator 120, a gas generator with a lower combustion temperature can be used. The combustion temperature of the first gas generator 110 and the second gas generator 120 can be set in the range of 1000°C to 1700°C. As such a first gas generator 110 and a second gas generator 120, for example, a known gas generator containing guanidine nitrate (41% by weight), basic copper nitrate (49% by weight), and an adhesive and an additive can be used. In addition, for the first gas generator 110 and the second gas generator 120, various shapes such as granular, pelletized, cylindrical, and disc-shaped can be used.

[0108] [Gas exhaust hole]

[0109] like Figure 1 As shown, a plurality of gas discharge holes 13 penetrating the inside and outside of the shell 1 are formed in a circumferentially arranged manner on the peripheral wall portion 11 of the shell 1. The gas discharge holes 13 penetrate from the inner surface 11a of the shell 1 (the inner peripheral surface of the peripheral wall portion 11) to the outer surface 11b (the outer peripheral surface of the peripheral wall portion 11). The internal space of the shell 1 (the first combustion chamber 10) is connected to the external space of the shell 1 via the gas discharge holes 13. Thus, the gas discharge holes 13 form a flow path for discharging the combustion gas from the inside of the shell 1 to the outside. It should be noted that in the technology disclosed in the present invention, the number of gas discharge holes may not be multiple, as long as more than one gas discharge hole is formed in the shell.

[0110] Figure 2 FIG. 1 is an enlarged cross-sectional view of the vicinity of the gas discharge hole 13 of the gas generator 100 according to the embodiment. Figure 2 The middle figure shows a cross section along the central axis CA1 of the housing 1 . Figure 2 The cross section shown is also a cross section along the thickness direction of the housing 1 . Figure 2 Reference numeral 13a1 indicates an opening of the gas discharge hole 13 on the inner surface 11a side of the shell 1, and reference numeral 13a2 indicates an opening of the gas discharge hole 13 on the outer surface 11b side of the shell 1. The cross section and opening of the gas discharge hole 13 of the present embodiment, which are orthogonal to the thickness direction (gas flow direction) of the shell 1, are formed into a circular (perfect circle) hole. However, the cross-sectional shape and the shape of the opening of the gas discharge hole disclosed in the present invention are not limited to a circle, and various shapes such as an ellipse, an oblong, a polygon, etc. can be adopted. The opening 13a of the gas discharge hole 13 is covered by a sealing tape S1.

[0111] like Figure 2As shown, the gas discharge hole 13 has: a chamfered area 131 obtained by removing the corner of the opening portion on the inner surface 11a side of the shell 1 throughout the entire circumference; and a straight area 132 connected to the chamfered area 131 and extending with a constant inner diameter along the thickness direction of the shell 1. In the gas discharge hole 13, the chamfered area 131 opens on the inner surface 11a side of the shell 1, and the straight area 132 opens on the outer surface 11b side of the shell 1. The chamfered area 131 of the gas discharge hole 13 forms the opening 13a by opening on the inner surface 11a. The straight area 132 of the gas discharge hole 13 forms the opening 13b by opening on the outer surface 11b. Reference numeral 13a1 indicates the periphery of the opening 13a, and reference numeral 13b1 indicates the periphery of the opening 13b. In addition, reference numeral 13 c 1 denotes a boundary portion between an inner wall surface 1311 forming the chamfered region 131 and an inner wall surface 1321 forming the straight region 132 .

[0112] The chamfered area 131 is formed in a tapered shape in such a way that the diameter decreases as it moves away from the opening 13a on the inner surface 11a side of the housing 1 in the thickness direction of the housing. Therefore, the cross-sectional area of ​​the chamfered area 131 decreases as it moves away from the opening 13a on the inner surface 11a side of the housing 1 in the thickness direction of the housing. Therefore, the inner wall surface 1311 forming the chamfered area 131 in the inner wall surface of the gas discharge hole 13 has a cylindrical shape that decreases in diameter as it moves away from the opening 13a on the inner surface 11a side of the housing 1 in the thickness direction of the housing, and is formed in a straight line shape inclined relative to the thickness direction in a cross section along the thickness direction of the housing 1. Thus, the inner wall surface 1311 faces the inner side of the housing 1.

[0113] The straight region 132 is formed to have a constant cross section (cross-sectional shape and cross-sectional area) in the thickness direction of the housing 1. The inner wall surface 1321 forming the straight region 132 in the inner wall surface of the gas discharge hole 13 has a cylindrical shape with a constant diameter in the thickness direction of the housing 1, and is formed in a straight line extending in the thickness direction in the cross section along the thickness direction of the housing 1.

[0114] The details will be described later, but the gas discharge hole 13 is formed by drilling a through hole in the housing 1 by drilling or punching, and removing the corner of the opening on the inner surface 11a side of the housing 1 by chamfering. The chamfered area 131 of this embodiment is formed into a tapered shape by so-called C-chamfering, and the chamfer angle θ relative to the inner surface 11a of the housing 1 is 45 [°]. However, the chamfer angle θ ( Figure 2The value of the angle of θ in the angle is not limited to this, as long as θ<90°. For example, the width dimension of the chamfered area 131 is set to the chamfer width W [mm], and the depth dimension is set to the chamfer depth D [mm]. In this example, the chamfered area 131 is formed by a C chamfer with a chamfer angle θ=45 [°], so the chamfer width W is equal to the chamfer depth D. The values ​​of W and D in the C chamfer are set to the chamfer amount X (the distance from the top of the raw material to be chamfered: mm). It should be noted that in the technology disclosed in the present invention, the chamfer width and the chamfer depth do not have to be equal, and they can also be different from each other.

[0115] In addition, the diameter of the straight area 132 is set as the aperture The diameter of the opening 13a of the gas discharge hole 13 on the inner surface 11a side of the housing 1 is defined as the opening diameter At this time, the opening diameter It is expressed by the following equation (1).

[0116]

[0117] When the chamfer angle θ is 45°, the chamfer amount X is equal to the opening diameter of the gas discharge hole 13. The ratio of is defined as chamfer ratio P [%]. The chamfer ratio P is represented by the following formula (2).

[0118]

[0119] The chamfer ratio P is preferably set to 2.9[%]≤P≤100[%], more preferably to 2.9[%]≤P≤50[%], more preferably to 2.9[%]≤P≤30[%], and more preferably to 2.9[%]≤P≤10[%].

[0120] Here, the angle of the inferior angle formed by the inner surface 11a of the shell 1 and the inner wall surface 1311 of the chamfered area 131 in the cross section along the thickness direction of the shell 1 is set to θ1. At this time, θ1>90[°] (in this example, θ1=135[°]). Similarly, the angle of the inferior angle formed by the inner wall surface 1311 of the chamfered area 131 and the inner wall surface 1321 of the straight tube area 132 in the cross section along the thickness direction of the shell 1 is set to θ2. At this time, θ2>90[°] (in this example, θ2=135[°]). That is, θ1 and θ2 are respectively obtuse angles.

[0121] Here, if Figure 2 As shown, the area of ​​the cross section of the gas discharge hole 13 perpendicular to the thickness direction of the housing 1 is smallest in the straight region 132. The minimum cross-sectional area of ​​the gas discharge hole 13 in the cross section perpendicular to the thickness direction of the housing 1 is denoted by A1. Figure 2The cross-sectional view CS1 shows a cross section perpendicular to the thickness direction of the housing 1 in the straight region 132. As shown in the cross-sectional view CS1, in the gas discharge hole 13 of the present embodiment, the straight region 132 has the smallest cross-sectional area A1.

[0122] [Sealing tape]

[0123] like Figure 1 As shown, a sealing tape S1 is mounted on the inner surface 11a of the housing 1. The sealing tape S1 is an example of a "seal" disclosed in the present invention. The sealing tape S1 is formed in a sheet shape (a tape shape in this example), and is a metal member that blocks the gas discharge hole 13 before the igniter is operated, and cracks when the igniter is operated to open the gas discharge hole 13. Because it is made of metal, the sealing tape S1 has a certain degree of flexibility or ductility at least with respect to the pressure of the combustion gas.

[0124] Figure 3 2 is a cross-sectional view for explaining the structure of the sealing band S1 of the gas generator 100 according to the embodiment. Figure 3 The middle figure shows a state where a sealing tape S1 is mounted on the inner surface 11a of the housing 1. The sealing tape S1 is, for example, a strip-shaped member having an adhesive layer formed on one side of a metal base material layer. Figure 3 As shown, the sealing tape S1 includes an aluminum base material layer S11 and an adhesive layer S12 provided on one side of the base material layer S11, and the adhesive layer S12 is bonded to the inner surface 11a of the shell 1, thereby assembling the sealing tape S1 to the inner surface 11a. It should be noted that the base material layer S11 is preferably made of aluminum, but is not limited thereto, and may also be made of stainless steel or copper. The adhesive layer S12 may be a layer made of a known synthetic resin-based adhesive. As the adhesive, silicone-based, rubber-based, epoxy-based adhesives, etc. are preferred from the viewpoint of heat resistance and adhesion. However, the material of the sealing tape S1 is not limited to the above. Here, as Figure 3 As shown, the thickness of the base material layer S11 is denoted as t1, the thickness of the adhesive layer is denoted as t2, and the thickness of the sealing tape S1 is denoted as t3.

[0125] like Figure 2 As shown, the sealing tape S1 is assembled to the inner surface 11a in a state of covering the opening of the inner surface 11a side of the shell 1 of the gas discharge hole 13, thereby blocking the plurality of gas discharge holes 13. Therefore, the chamfered area 131 of all the gas discharge holes 13 is covered by the sealing tape S1. Before the igniter (first igniter 41) works, the gas discharge hole 13 is blocked by the sealing tape S1, thereby preventing the outside air (moisture) from invading the interior of the shell 1 through the gas discharge hole 13, and maintaining the interior of the shell 1 airtight. Moreover, when the first igniter 41 works, the sealing tape S1 is cracked by the pressure of the generated gas, thereby opening the plurality of gas discharge holes 13.

[0126] Here, in this specification, the pressure required to crack the seal (in this example, the sealing tape S1) in each gas discharge hole and open the gas discharge hole is defined as "cracking pressure". When the seal cracks, the seal subjected to the pressure of the combustion gas is pressed against the periphery of the opening on the inner surface side of the shell of the gas discharge hole. Therefore, the cracking pressure of the seal of each gas discharge hole is determined according to the specifications of the seal and the shape of the opening of the gas discharge hole. The specifications of the seal specifically refer to the tensile strength and thickness of the seal. The lower the tensile strength of the seal or the thinner the thickness of the seal, the lower the cracking pressure.

[0127] In addition, in this specification, the area of ​​the cross section of the combustion gas flow path (gas flow path) formed in the gas discharge hole 13 by the cracking of the sealing tape S1, which is orthogonal to the flow direction of the combustion gas, is defined as the flow path cross-sectional area. In the present embodiment, the direction in which the gas discharge hole 13 penetrates the shell 1, that is, the thickness direction of the shell 1, becomes the flow direction of the combustion gas. Moreover, the cross-sectional area that becomes the smallest in the gas flow path is defined as the minimum flow path cross-sectional area. In the gas flow path, the part that becomes the minimum flow path cross-sectional area becomes the speed limit (throttling) of the gas discharge. The effective cross-sectional area through which the gas can actually flow in the gas flow path becomes a size corresponding to the minimum flow path cross-sectional area. That is, the gas discharge amount per unit time of the gas discharge hole 13 is determined according to the minimum flow path cross-sectional area of ​​the gas flow path formed in the gas discharge hole 13. Moreover, by adjusting the number of open gas discharge holes and the gas discharge amount per unit time of the gas discharge holes, the internal pressure of the shell 1 can be controlled.

[0128] [action]

[0129] Below, refer to Figure 1 The basic operation of the gas generator 100 of the present embodiment will be described. In this example, the case where the second ignition device 7 is operated later than the first ignition device 4 (that is, after the first ignition device 4 is operated) will be described.

[0130] When the sensor (not shown) senses the impact, the ignition current is supplied to the first igniter 41 of the first ignition device 4, and the first igniter 41 operates. Then, the detonator contained in the first igniter 41 burns, and the flame, high-temperature gas, etc. as the combustion products are discharged into the ignition chamber 53. As a result, the ignition powder 6 contained in the ignition chamber 53 burns, and combustion gas is generated in the ignition chamber 53. When the sealing tape that blocks the communication hole h1 of the surrounding wall portion 51 of the first inner cylinder member 5 is ruptured due to the pressure of the combustion gas of the ignition powder 6, the combustion gas is discharged to the outside of the ignition chamber 53 through the communication hole h1. Then, the combustion gas of the ignition powder 6 contacts the first gas generating agent 110 arranged around the surrounding wall portion 51, and the first gas generating agent 110 is ignited. The first gas generating agent 110 burns, thereby generating high-temperature / high-pressure combustion gas in the first combustion chamber 10. The sealing tape S1 is ruptured by the pressure of the combustion gas, thereby opening a plurality of gas discharge holes 13. The combustion gas is cooled and combustion residues are collected by passing through the filter 9 . The combustion gas of the first gas generating agent 110 cooled and filtered by the filter 9 is introduced into the annular space 12 , and is discharged to the outside of the housing 1 through the plurality of gas discharge holes 13 .

[0131] Next, when the second igniter 71 of the second ignition device 7 is operated, the second gas generating agent 120 contained in the second combustion chamber 20 is burned, and combustion gas is generated in the second combustion chamber 20. When the sealing band blocking the communication hole h2 of the surrounding wall portion 81 of the second inner cylinder member 8 is ruptured by the pressure of the combustion gas of the second gas generating agent 120, the combustion gas is discharged to the first combustion chamber 10 through the communication hole h2. The combustion gas of the second gas generating agent 120 is cooled and filtered by the filter 9, and then introduced into the annular space 12, and is discharged to the outside of the housing 1 through the plurality of gas discharge holes 13.

[0132] The combustion gas of the first gas generating agent 110 and the second gas generating agent 120 flows into an airbag (not shown) after being discharged to the outside of the housing 1. The airbag expands to form a buffer between the occupant and a hard structure, thereby protecting the occupant from impact.

[0133] [Gas discharge method of gas generator]

[0134] Next, a method for discharging gas from the gas generator of the present embodiment (gas discharging method) will be described. However, the method for discharging gas from the gas generator disclosed in the present application is not limited to the following method. Figure 4 1 is a flow chart of a method for discharging gas from a gas generator according to an embodiment of the present invention. Figure 4As shown, the gas exhaust method of the gas generator of this embodiment includes: a shell preparation process in step S101; a gas exhaust hole blocking process in step S102; a gas generator assembly process in step S103; an igniter operation process in step S104; and a seal cracking process in step S105.

[0135] First, in the casing preparation process of step S101 , the casing 1 in which the gas discharge holes 13 are formed is prepared. Figure 5 and Figure 6 2 is a cross-sectional view for explaining the preparation process of the housing according to the embodiment. Figure 5 and Figure 6 , the figure shows a cross section along the thickness direction of the housing 1. In the housing preparation step, the gas discharge hole 13 is formed in the housing 1.

[0136] In forming the gas discharge hole 13, first, as Figure 5 As shown, a through hole 14 is formed in the housing 1, and the through hole 14 extends with a constant inner diameter along the thickness direction of the housing 1. The through hole 14 is punched at a position where the gas discharge hole 13 is to be formed in the housing 1, for example, by drilling or punching. Figure 5 Reference symbol AC1 denotes a corner portion of the opening of the through hole 14 on the inner surface 11a side of the housing 1. Figure 6 As shown, the corner AC1 is removed throughout the entire circumference by C-chamfering, thereby forming a chamfered area 131 and a straight area 132. The area in the through hole 14 removed by chamfering forms the chamfered area 131, and the area that is not removed and remains forms the straight area 132. The chamfered area 131 is formed to reduce in diameter as it moves away from the opening 13a on the inner surface 11a side of the shell 1 in the thickness direction of the shell. The inner wall surface 1311 of the chamfered area 131 is formed to be a straight line inclined relative to the thickness direction in a cross section along the thickness direction of the shell 1. The straight area 132 is formed to open on the outer surface of the shell with the boundary portion 13c1 as the starting point and extend with a fixed inner diameter. The inner wall surface 1321 of the straight area 132 is formed to be a straight line extending along the thickness direction in a cross section along the thickness direction of the shell 1. In this way, a gas discharge hole 13 having a chamfered area 131 and a straight area 132 is formed in the shell 1.

[0137] Next, in the gas discharge hole plugging process of step S102, a sealing tape S1 is attached to the inner surface 11a of the housing 1 to cover the openings 13a of the gas discharge holes 13 on the inner surface 11a side of the housing 1. Thus, all the gas discharge holes 13 are plugged.

[0138] Next, in the assembly process of the gas generator in step S103, the first ignition device 4 and the second ignition device 7 are assembled on the lower housing 3, the first inner cylinder member 5 filled with the ignition powder 6 is fixed to the first ignition device 4, and the second inner cylinder member 8 filled with the second gas generating agent 120 is fixed to the second ignition device 7. After that, the filter 9 is arranged on the lower housing 3, and the first gas generating agent 110 is filled inside the filter 9. Finally, the upper housing 2 is covered on the lower housing 3, and the joint portion 23 of the upper housing 2 and the joint portion 33 of the lower housing 3 are overlapped and joined by laser welding or the like, thereby forming the housing 1. As described above, the gas generator 100 is assembled.

[0139] Next, in the igniter operation process of step S104, the igniter of the gas generator 100 is operated. It should be noted that, when the gas generator 100 operates the second igniter 71 after the first igniter 41 is operated, the next step (step S105) is entered after the first igniter 41 is operated and before the second igniter 71 is operated.

[0140] Next, in the seal rupture step of step S105 , the seal band S1 is ruptured by the pressure of the combustion gas generated by the operation of the igniter. Figure 7 and Figure 8 2 is a cross-sectional view for explaining the cleavage process of the seal member according to the embodiment. Figure 7 and Figure 8 , a cross section along the thickness direction of the housing 1 is shown.

[0141] As described above, before the igniter is operated, the sealing tape S1 covers the chamfered area 131, and the inner wall surface 1311 of the chamfered area 131 faces the inner side of the housing 1. Therefore, when the igniter is operated, Figure 7 As shown, the sealing tape S1 is extended and deformed toward the outer side of the housing 1 due to the pressure of the combustion gas, and is pressed to the inner wall surface 1311 of the chamfered area 131. At this time, the sealing tape S1 is bent at the opening edge 13a1 and stretched along the inner wall surface 1311 of the chamfered area 131. Here, the area of ​​the sealing tape S1 that is assembled to the inner surface 11a of the housing 1 is set as the installation area S1a, the annular area that abuts against the inner wall surface 1311 of the chamfered area 131 is set as the abutment area S1b, and the area inside the abutment area S1b is set as the inner area S1c.

[0142] In addition, the sealing band S1 is stretched and deformed by the pressure of the combustion gas, thereby Figure 7 As shown, the inner region S1 c reaches the straight region 132 of the gas discharge hole 13 .

[0143] In this state, the pressure of the combustion gas further acts on the inner region S1c, and the tensile load of the inner region S1c exceeds the tensile strength of the sealing tape S1. Figure 8 As shown, the inner area S1c is cracked due to ductile failure (fracture). That is, the sealing band S1 is broken by film destruction starting from the central part of the inner area S1c. The combustion gas is discharged through the gas discharge hole 13. In addition, in a state where at least a part of the installation area S1a of the sealing band S1 remains on the inner surface 11a of the shell 1, the inner area S1c is cracked in the gas discharge hole 13, thereby forming a crack piece F1 of the sealing band S1 in the gas discharge hole 13. The crack piece F1 is formed by a part of the cracked inner area S1c, but may also include a part of the abutment area S1b. The crack piece F1 is connected to the installation area S1a, and can be bent by the pressure of the combustion gas with the installation area S1a as the base end. Therefore, the discharge of the combustion gas will not be affected by the crack piece F1.

[0144] Assuming that the chamfered area 131 is not formed in the gas discharge hole 13, the corner AC1 of the opening on the inner surface 11a side of the housing 1 (see Figure 5 ) is not removed, the sealing tape S1 is pressed against the corner AC1 by the pressure of the combustion gas, and shear force acts on the sealing tape S1. As a result, the sealing tape S1 is integrally punched and cracked along the opening edge of the gas discharge hole 13 due to shear failure. Therefore, the sealing tape S1 is not likely to remain in the gas discharge hole 13. Moreover, the fragments of the punched sealing tape S1 may be discharged to the outside of the housing 1 (outside the gas generator 100) by the pressure of the combustion gas.

[0145] In this regard, in the present embodiment, a chamfered area 131 is formed in the gas discharge hole 13, and the sealing tape S1 is blocked by the inner wall surface 1311 of the chamfered area 131, so that after the sealing tape S1 is ruptured, the ruptured pieces F1, which are part of the sealing tape S1, remain in the gas discharge hole 13. Therefore, when the combustion gas passes through the gas discharge hole 13, at least a part of the combustion residue contained in the combustion gas collides with the ruptured pieces F1, thereby preventing the combustion residue from passing through the gas discharge hole 13 and being discharged to the outside of the gas generator 100. As a result, the discharge amount of the combustion residue is reduced. In addition, at least a part of the sealing tape S1 remains in the gas discharge hole 13 as the ruptured pieces F1, thereby reducing the amount of fragments of the sealing tape S1 discharged to the outside of the gas generator 100 by the pressure of the combustion gas.

[0146] Here, the minimum flow path cross-sectional area of ​​the gas flow path FP1 formed in the gas discharge hole 13 by rupturing the sealing tape S1 is represented by A2. Figure 8The cross-sectional view CS2 shows a cross-section orthogonal to the thickness direction of the housing 1 in the straight cylinder region 132. As shown in the cross-sectional view CS2, the gas flow path FP1 has the minimum flow path cross-sectional area A2 in the straight cylinder region 132.

[0147] Assume that the cracked sealing band S1 has not reached the straight cylinder region 132. Then, the minimum flow path cross-sectional area A2 is equal to the minimum cross-sectional area A1 of the gas discharge hole 13. However, in the present embodiment, the sealing band S1 reaches the straight cylinder region 132. Therefore, the gas flow path FP1 narrows in the straight cylinder region 132. Thus, the minimum flow path cross-sectional area A2 (effective cross-sectional area) of the gas flow path FP1 is smaller than the minimum cross-sectional area A1 of the gas discharge hole 13. That is, A2 < A1. As a result, compared with the case where the sealing band S1 does not reach the straight cylinder region 132, the effective cross-sectional area through which gas can actually flow in the gas flow path FP1 becomes smaller. Thereby, the discharge amount of combustion residues is also reduced.

[0148] In addition, in the present embodiment, the combustion gas generated by the operation of the igniter and passing through the filter 9 is introduced into the annular space 12, thereby equalizing the pressure of the combustion gas in the space 12. By equalizing the pressure in the annular space, the pressure can act on the sealing band S1 uniformly in the plurality of gas discharge holes 13. Thereby, the sealing band S1 can be cracked equally in the plurality of gas discharge holes 13. It should be noted that in the gas generator 100 of the present embodiment, chamfered regions 131 are provided in the plurality of gas discharge holes 13 to generate cracking pieces F1. However, after the igniter operates, a part of the sealing band S1 does not need to remain in all the gas discharge holes 13.

[0149] [Function / Effect]

[0150] As described above, the gas generator 100 of the present embodiment includes: a gas discharge hole 13 penetrating the housing 1 that contains the igniter and the gas generating agent; and a metal sealing tape S1 formed in a sheet shape. The sealing tape S1 is mounted on the inner surface of the housing 1, and covers the opening 13a on the inner surface 11a side of the housing 1 of the gas discharge hole 13 before the igniter is operated, thereby blocking the gas discharge hole 13, and is cracked by the pressure of the combustion gas generated by the operation of the igniter, thereby opening the gas discharge hole 13. In addition, the gas discharge hole 13 has a chamfered area 131 obtained by removing the corner of the opening 13a on the inner surface 11a side of the housing 1 over the entire circumference. As a result, the sealing tape S1 that is subjected to the pressure of the combustion gas when the igniter is operated is blocked by the inner wall surface 1311 of the chamfered area 131, thereby suppressing the shear failure of the sealing tape S1 and making it easy to break due to tension. Thus, after the sealing tape S1 is ruptured, the cleavage piece F1, which is at least a part of the sealing tape S1, can remain in the gas discharge hole 13. Thus, the cleavage piece F1 prevents the combustion residue contained in the combustion gas from passing through the gas discharge hole 13 and being discharged to the outside of the gas generator 100. As a result, the amount of the combustion residue discharged from the gas generator 100 can be reduced.

[0151] In addition, the gas generator 100 of the present embodiment is configured such that the minimum flow path cross-sectional area A2 of the gas flow path FP1 formed in the gas discharge hole 13 by the rupture of the sealing tape S1 is smaller than the minimum cross-sectional area A1 of the gas discharge hole 13. As a result, the effective cross-sectional area of ​​the gas flow path FP1 can be reduced, and the discharge amount of the combustion residue can be further reduced. It should be noted that in the present embodiment, the effective cross-sectional area of ​​the gas flow path FP1 is reduced by a portion of the sealing tape S1 that reaches the straight tube area 132, but the scheme for reducing the effective cross-sectional area is not limited to this. In addition, in the technology disclosed in the present invention, the gas discharge hole does not have to have a straight tube area. For example, the gas discharge hole can also be a drum-shaped hole having a tapered area that expands in diameter as it moves away from the chamfered area toward the outer side of the shell in the thickness direction of the shell as an area connected to the chamfered area.

[0152] Here, in the sealing tape S1 including the above-mentioned aluminum base material layer S11 and the adhesive layer S12 provided on one side of the base material layer S11 and bonded to the inner surface of the housing 1, the thickness t1 of the base material layer S11 is preferably greater than 50 [μm] and less than 200 [μm]. Thus, the shear failure of the sealing tape S1 subjected to the pressure of the combustion gas after the igniter is operated can be suppressed, and it is easy to break due to stretching. In addition, from the viewpoint of suppressing shear failure, the tensile strength of the sealing tape S1 measured according to JIS Z0237 is further preferably greater than 100 [N] / 20 [mm] and less than 200 [N] / 20 [mm]. However, the thickness of the base material layer of the seal disclosed in the present invention and the tensile strength of the seal are not limited to the above.

[0153] [Modification of the embodiment]

[0154] Hereinafter, a gas generator according to a modified example of the embodiment will be described. Figures 1 to 8 The description will focus on the differences among the schemes described in the description, and detailed descriptions of the same points will be omitted.

[0155] [Modification 1]

[0156] Fig. 9 This is an enlarged cross-sectional view of the vicinity of gas discharge hole 13A of gas generator 100A according to Modification 1. Fig. 9 and Figure 2 Correspondingly, the figure shows a cross section along the thickness direction of the housing 1.

[0157] The gas discharge hole 13A of the modification example 1 is formed as a hole whose cross section and opening are perpendicular to the thickness direction of the housing 1 and are circular (perfectly circular). Fig. 9 As shown, the gas exhaust hole 13A has a chamfered area 131A obtained by removing (rounding) the corners of the opening part on the inner surface 11a side of the shell 1 throughout the entire circumference, and a straight tube area 132 connected to the chamfered area 131A and extending with a fixed inner diameter along the thickness direction of the shell 1.

[0158] The chamfered area 131A of Modification 1 is formed so as to decrease in diameter as it moves away from the opening 13a on the inner surface 11a side of the housing 1 in the thickness direction of the housing. Therefore, the inner wall surface 1311A forming the chamfered area 131A has a cylindrical shape that decreases in diameter as it moves away from the opening 13a on the inner surface 11a side of the housing 1 in the thickness direction of the housing, and is formed in an arc shape that is curved in a convex manner toward the inner side of the housing 1 in a cross section along the thickness direction of the housing 1. Thus, the inner wall surface 1311A faces the inner side of the housing 1.

[0159] In step S101 (shell preparation process) of the above-mentioned gas exhaust method, the gas exhaust hole 13A is formed by drilling a through hole in the shell 1 by drilling or punching, and the corner of the opening on the inner surface 11a side of the shell 1 is rounded by so-called R chamfering. By R surface processing, the inner wall surface 1311A of the chamfered area 131 is formed into a curved shape (arc shape in this example) in the cross section along the thickness direction of the shell 1. When the curvature radius of the R chamfer is set to R [mm], W = D = R. It should be noted that the inner wall surface 1311A of the chamfered area 131A may also be a curved shape other than an arc in the cross section along the thickness direction of the shell 1, and the chamfer width W and the chamfer depth D may not be equal.

[0160] In the gas generator 100A of the modification 1, the same effects as those of the gas generator 100 described above can also be achieved. That is, after the sealing tape S1 is ruptured, the ruptured piece F1, which is at least a part of the sealing tape S1, can remain in the gas discharge hole 13A. As a result, the amount of combustion residue discharged from the gas generator 100 can be reduced. In addition, the gas generator 100A is also configured so that the minimum flow path cross-sectional area of ​​the gas flow path formed in the gas discharge hole 13A by the rupture of the sealing tape S1 is smaller than the minimum cross-sectional area of ​​the gas discharge hole 13A. As a result, the effective cross-sectional area of ​​the gas flow path can be reduced, and the discharge amount of combustion residue can be further reduced.

[0161] [Modification 2]

[0162] Fig.10 2 is a cross-sectional view for explaining the structure of a seal band S1B of a gas generator 100B according to a second modification. Fig.10 The middle figure shows a state where a sealing tape S1B is installed on the inner surface 11a of the housing 1. Fig.10 As shown, the sealing tape S1B includes: an aluminum base material layer S11; an adhesive layer S12, which is provided on one side of the base material layer S11 and is bonded to the inner surface 11a of the housing 1; and an adhesive layer S13, which is provided on the other side of the base material layer S11 and has adhesive properties. Fig.10 As shown, the adhesive layer S13 faces the inner side of the housing 1. The adhesive layer S13, like the adhesive layer S12, can be a layer made of a known synthetic resin adhesive.

[0163] The gas generator 100B of the second modification can also achieve the same effects as those of the gas generator 100 described above. In addition, in the gas generator 100B of the second modification, the adhesive layer S13 is provided on the sealing tape S1 so as to face the inner side of the housing 1. Therefore, after the sealing tape S1B is ruptured, the combustion residue can be attached to the adhesive layer S13 of a part of the sealing tape S1B (the ruptured piece F1) remaining in the gas discharge hole 13 and captured. As a result, the discharge amount of the combustion residue can be further reduced.

[0164] [Combustion residue amount measurement test]

[0165] A test (combustion residue amount measurement test) was conducted to measure the amount of combustion residue discharged from the gas generator of the embodiment of the present disclosure. Hereinafter, the present disclosure will be specifically described with reference to the embodiment. However, the present disclosure is not limited to the schemes of the following embodiment.

[0166] In the test, the gas generators of the embodiment and the comparative example described below were operated, and the discharge amount of the combustion residue discharged from the gas discharge hole to the outside of the housing was measured. Figure 1 to Figure 4 , Figure 6 to Figure 8The gas generator 100 of the embodiment described in the embodiment is different from the embodiment in that the gas discharge hole of the comparative example does not have a chamfered area. That is, the entire area of ​​the gas discharge hole of the comparative example is equivalent to the straight tube area. In the embodiment and the comparative example, the diameter of the hole provided with the straight tube area in the shell is Different two gas discharge holes. The two gases are discharged through the hole with different diameters. The larger one is called a "large hole", and the smaller one is called a "small hole". The gas exhaust hole of the embodiment is formed by chamfering the through hole drilled by drilling, and the gas exhaust hole of the comparative example is formed by punching (punching by a press) without chamfering. The explosive or gas generating agent is used in the embodiment and the comparative example in equal amounts and with the same specifications. The sealing tape has a base material layer thickness t1 = 100 [μm], an adhesive layer thickness t2 = 50 [μm], and a tensile strength of 119 [N] / 20 [mm] measured according to JIS Z0237.

[0167] Regarding the embodiment and the comparative example, the discharge amount of the combustion residue was measured for the case where the first igniter and the second igniter were operated simultaneously and the case where the second igniter was operated after the first igniter was operated for 100 [msec]. In addition, three embodiments and comparative examples were prepared, and the discharge amount of the combustion residue was measured. In the embodiment and the comparative example, the average value of the discharge amount of the combustion residue was calculated.

[0168] Fig.11 This is a table showing the results of the combustion residue amount measurement test. Fig.11 In the table, the "large hole" The value recorded in this column is the diameter of the straight area of ​​the large hole. The value recorded in the "Number [pcs]" column for "Large holes" is the number of large holes. The value recorded in this column is the diameter of the straight area of ​​the small hole. The numerical value recorded in the column "Number [pieces]" of "Small holes" is the number of small holes.

[0169] Fig.11 In the table, the value recorded in the "Simultaneous ignition" column of "Amount of combustion residue [mg]" is the average value [mg] of the emission of combustion residue when the first igniter and the second igniter are operated simultaneously, and the value recorded in the "Delayed ignition" column is the average value [mg] of the emission of combustion residue when the second igniter is operated with a delay of 100 [msec] after the first igniter is operated.

[0170] like Fig.11As shown, in both the simultaneous ignition and the delayed ignition, the emission of combustion residues in the embodiment is less than that in the comparative example. Based on the above test results, it can be confirmed that the emission of combustion residues can be reduced by the embodiment of the present disclosure.

[0171] [Chamfer ratio evaluation test]

[0172] The chamfering amount X and the opening diameter of the inner surface side of the housing of the gas discharge hole are compared. A test was conducted to evaluate the relationship between the ratio of chamfer ratio P [%] and the crack state of the sealing tape (chamfer ratio evaluation test).

[0173] Fig.12 The table shows the results of the chamfer ratio evaluation test. In the test, a shell having a thickness of T1 = 1.4 [mm] was formed. Fig.12 The gas discharge holes No. 1 to 14 shown are blocked from the inner surface side of the shell by a sealing tape having a thickness of t3 = 100 [μm]. Then, the cracking state of the sealing tape when the pressure of the combustion gas is applied to the sealing tape from the inner surface side of the shell is evaluated. The gas discharge holes No. 1 to 12 are chamfered at a chamfering angle θ = 45 [°] to form a chamfered area. No chamfered area is formed in the gas discharge holes No. 13 and No. 14 (that is, the chamfering amount X = 0 [mm]). In addition, the gas discharge holes No. 1 to 13 are formed by drilling, and the gas discharge hole No. 14 is formed by punching (punching by a press). Fig.12 In the table, The value in this column is the opening diameter of the gas discharge hole on the inner surface of the shell. The numerical value recorded in the column “X [mm]” is the chamfering amount X [mm] of the opening of the gas discharge hole on the inner surface side of the housing. The numerical value recorded in the column “P [%]” is the chamfering ratio P [%].

[0174] Fig.12 In the table, the "Cracked State" column records the state of the sealing tape when it is cracked. In the case where the sealing tape is cut integrally along the opening edge of the gas discharge hole due to shear failure, "Shear" is recorded in the "Cracked State" column. In the case where the sealing tape is broken due to ductile failure (fracture) (in the case of film failure), "Fracture" is recorded in the "Cracked State" column.

[0175] like Fig.12 As shown in FIG. 1 , when 2.9[%]≤P, the sealing tape was film-broken. From the above evaluation results, it was confirmed that 2.9[%]≤P is preferably set.

[0176] <Others>

[0177] As described above, the gist of this embodiment is to make the cracking mode of the sealing tape ductile fracture by forming the chamfered area of ​​the gas discharge hole on the side of the shell to which the sealing tape is attached. As long as the minimum cross-sectional area A1 is ensured, it will not hinder the formation of the chamfered area of ​​the gas discharge hole on the outer side of the shell. The preferred embodiments of the present disclosure are described, but the various schemes disclosed in this specification can also be combined with any other features disclosed in this specification.

[0178] Description of Reference Numerals

[0179] 100: Gas generator;

[0180] 1: Shell;

[0181] 13: Gas discharge hole;

[0182] 131: chamfer area;

[0183] 132: straight area;

[0184] S1: Sealing tape.

Claims

1. A gas generator comprising: Igniter; a gas generating agent that burns through the operation of the igniter to generate combustion gas; a housing, accommodating the igniter and the gas generating agent therein; a gas discharge hole penetrating inside and outside of the shell; and a metal seal member formed in a sheet shape and mounted on the inner surface of the housing, covering the opening of the inner surface side of the housing of the gas discharge hole before the igniter is operated, thereby blocking the gas discharge hole, and being ruptured by the pressure of the combustion gas generated by the operation of the igniter, thereby opening the gas discharge hole, The gas discharge hole has a chamfered area obtained by removing a corner of an opening portion on the inner surface side of the housing over the entire circumference.

2. The gas generator according to claim 1, wherein: The chamfered area is formed so as to decrease in diameter as it becomes farther away from the opening portion on the inner surface side of the housing in the thickness direction of the housing.

3. The gas generator according to claim 2, wherein: The inner wall surface of the chamfered area is formed in a straight line or a curved line in a cross section along the thickness direction of the housing.

4. The gas generator according to claim 1, wherein: The gas discharge hole has a straight region connected to the chamfered region and extending with a constant inner diameter.

5. The gas generator according to any one of claims 1 to 4, wherein: The sealing member comprises: a base material layer made of aluminum; and an adhesive layer, which is disposed on one side of the base material layer and is bonded to the inner surface of the housing. The thickness of the base material layer is 50 [μm] or more and 200 [μm] or less.

6. The gas generator according to claim 5, wherein: The seal has a tensile strength of 100 [N] / 20 [mm] or more and 200 [N] / 20 [mm] or less as measured in accordance with JIS Z0237.

7. The gas generator according to claim 5, wherein: The sealing member further comprises an adhesive layer, which is arranged on the other side of the base material layer and has adhesiveness.

8. The gas generator according to any one of claims 1 to 4, wherein: The gas generator is configured such that when the sealing member is ruptured, at least a portion of the sealing member remains in the gas discharge hole.

9. The gas generator according to claim 8, wherein: The gas generator is configured such that, by rupturing the sealant, a minimum flow path cross-sectional area of ​​the combustion gas flow path formed in the gas discharge hole is made smaller than a minimum cross-sectional area of ​​the gas discharge hole.

10. A method for exhausting gas from a gas generator, comprising the following steps: The step of preparing a housing of the gas generator, the housing accommodating an igniter and a gas generating agent that burns to generate combustion gas when the igniter is operated, and the housing is formed with a gas discharge hole that penetrates inside and outside the housing, the gas discharge hole having a chamfered area obtained by removing corners of an opening portion on the inner surface side of the housing over the entire circumference; A step of attaching a sheet-shaped metal seal to the inner surface of the housing to cover the opening of the gas discharge hole on the inner surface side of the housing, thereby blocking the gas discharge hole; The step of assembling the gas generator; The step of operating the igniter; as well as The step of using the pressure of the combustion gas generated by the operation of the igniter to press the seal against the inner wall surface of the chamfered area, so that an area of ​​the seal that is closer to the inside than the abutting area against the inner wall surface of the chamfered area is cracked, thereby cracking the seal in a manner that at least a portion of the seal remains in the gas discharge hole.

11. The gas exhaust method of a gas generator according to claim 10, wherein: In the step of preparing the housing, the chamfered area is formed in the gas discharge hole in such a manner that the diameter thereof decreases as the opening on the inner surface side of the housing is away from the opening in the thickness direction of the housing. In the step of rupturing the sealing member, the sealing member is ruptured by bending the sealing member so as to be along the inner wall surface of the chamfered region.

12. The gas exhaust method of a gas generator according to claim 11, wherein: In the step of preparing the housing, an inner wall surface of the chamfered area is formed so as to be linear or curved in a cross section along a thickness direction of the housing.

13. The gas exhaust method of a gas generator according to any one of claims 10 to 12, wherein: In the step of preparing the housing, the gas discharge hole is formed in a straight cylindrical region opened on the outer surface of the housing and extending with a fixed inner diameter, In the step of rupturing the sealing member, the sealing member is ruptured by bending the sealing member so that at least a portion of the sealing member reaches the straight region.

14. The gas exhaust method of a gas generator according to any one of claims 10 to 12, wherein: In the step of rupturing the sealing member, the sealing member is ruptured by bending the sealing member so that a minimum flow path cross-sectional area of ​​the combustion gas flow path formed in the gas discharge hole becomes smaller than a minimum cross-sectional area of ​​the gas discharge hole.

15. The gas exhaust method of a gas generator according to any one of claims 10 to 12, wherein: In the step of blocking the gas discharge hole, the gas discharge hole is blocked by the sealing member including an aluminum base material layer and an adhesive layer provided on one surface of the base material layer and bonded to the inner surface of the housing.

16. The gas exhaust method of a gas generator according to any one of claims 10 to 12, wherein: A plurality of gas discharge holes are formed in the shell, In the step of assembling the gas generator, a cylindrical filter is disposed inside the housing so as to form an annular space between the filter and the inner surface of the housing. In the step of rupturing the seal, the combustion gas generated by the operation of the igniter and passing through the filter is introduced into the annular space so that the pressure in the annular space is made uniform, and then pressure is applied to the seal.

17. The gas exhaust method of a gas generator according to any one of claims 10 to 12, wherein: In the step of rupturing the sealing member, the sealing member is stretched by the pressure of the combustion gas, and the sealing member is ruptured by bending the sealing member while at least a portion of the sealing member remains in the gas discharge hole.

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