Gas generator

Abstract

[Problem] To obtain a gas generator which can reduce the number of components and is easy to assemble while suppressing deterioration of a gas generating agent in a housing due to moisture absorption. [Solution] A gas generator 100 comprises: a housing 10; a holder (20) attached to one open end of the housing (10); a closing member (12) attached to the other end of the housing (10) so as to close the other open end of the housing (10); and a side cover 51 that covers a part of the holder 20 and a part of the igniter 50. The end portion of the side cover 51 is welded and fixed to the housing 10 and the holder 20 in the welding and fixing portion 62 in a state in which the side cover 51 is sandwiched between the inner wall of the housing 10 and the side surface portion 22. The welding fixing part 62 is formed in a ring shape in the circumferential direction of the housing 10 by welding from the outside of the housing 10 in the circumferential direction of the housing 10 at a position corresponding to the side surface part 22 covered by the side cover 51.

Description

Technical Field

[0001] The present invention relates to a gas generator incorporated in an air bag device as an occupant protection device mounted on an automobile or the like, and more particularly to a so-called cylinder-type gas generator having an elongated cylindrical shape. Background Art

[0002] In a cylinder-type gas generator, a casing having an elongated cylindrical shape is generally configured such that at least one end thereof is closed by a holder having an ignition portion (for example, see Patent Document 1 listed below).

[0003] Prior art literature:

[0004] Patent Literature

[0005] Patent Document 1: U.S. Patent No. 6149193

[0006] Patent Document 2: U.S. Patent No. 9455519 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In the above-mentioned Patent Document 1, since there are multiple air circulation paths between the internal space filled with the gas generating agent in the shell and the outside of the shell, there is a concern that the gas generating agent in the shell will deteriorate due to moisture absorption. In addition, in the above-mentioned Patent Document 2, in order to suppress the moisture absorption of the gas generating agent in the shell, O-rings or sealing materials are used. However, components such as O-rings or sealing materials usually need to be provided in each of the above-mentioned air circulation paths, which tends to increase the number of components. This increase in the number of components has the problem of making the assembly process of the gas generator complicated.

[0009] Therefore, an object of the present invention is to provide a gas generator that can reduce the number of parts and facilitate assembly while suppressing the degradation of a gas generating agent in a casing due to moisture absorption.

[0010] Solution to the problem

[0011] (1) The gas generator of the present invention is characterized in that it comprises: a slender cylindrical shell, which contains a working gas generating chamber inside which generates working gas by burning a gas generating agent, and a filter chamber that accommodates a filter through which the working gas generated in the working gas generating chamber passes; a gas generating agent ignition device, which contains ignition powder and is arranged at one axial end of the shell, and can ignite and burn the gas generating agent in the working gas generating chamber; a retaining member, which is fixed to one axial end of the shell, and has a generally cylindrical first forming portion, the first forming portion having a retaining portion for retaining the gas generating agent ignition device on the inner side of the shell, and a generally cylindrical second forming portion, the second forming portion being provided on a side of the first forming portion opposite to the side of the working gas generating chamber. The side cover is a bottomed cylindrical member having a cylindrical portion, which covers at least a portion of the working gas generating chamber side of the gas generating agent ignition device and at least a portion of the side surface of the first forming portion, and the cylindrical portion is arranged in a manner clamped by the inner wall of the shell and the side surface of the first forming portion, and at least a portion of a position of the shell corresponding to the side surface of the first forming portion covered by the side cover, a portion of the side cover corresponding to the portion, and a portion of the side surface of the retaining member corresponding to the portion are welded and fixed into a ring shape along the circumference of the shell.

[0012] (2) In the gas generator of (1) above, the welding and fixing is preferably performed along a position of an end portion of the side cover on the retainer side.

[0013] (3) In the gas generator of (1) or (2) above, preferably, at the end of the side cover on the working gas generating chamber side, there are formed: a bottom portion; and a tapered portion connected to the bottom portion and tapering toward the other end side of the housing in the axial direction.

[0014] According to the above-described configurations, it is possible to provide a gas generator that can suppress the gas generating agent in the casing from being deteriorated due to moisture absorption and that can be easily assembled. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram showing the internal structure of the gas generator according to the embodiment of the present invention, partially shown in cross section.

[0016] Figure 2 yes Figure 1 A partially enlarged cross-sectional view of .

[0017] Figure 3 Yes means Figure 2Figure 1 shows the state before welding fixation.

[0018] Figure 4 It is shown Figure 1 A cross-sectional view of an example of a side cover.

[0019] Figure 5 It is shown Figure 1 A cross-sectional view of an example of a side cover.

[0020] Figure 6 It is shown Figure 1 A cross-sectional view of an example of a side cover. DETAILED DESCRIPTION

[0021] Below, refer to Figures 1 to 3 , the internal structure of the cylinder type gas generator according to an embodiment of the present invention is described.

[0022] (Structure of Gas Generator 100)

[0023] like Figure 1 As shown, the gas generator 100 has a slender, roughly cylindrical shape, and includes: a shell 10; a retaining member 20 installed at an open end of the shell 10; a closing member 12 installed at the other end of the shell 10 in a manner to close the other open end of the shell 10; and a side cover 51 covering a portion of the retaining member 20 and a portion of the igniter 50.

[0024] The housing 10 is composed of an elongated cylindrical member having openings at both ends in the axial direction. The blocking member 12 is composed of a disc-shaped member having a predetermined thickness, and has a welded fixing portion 60 on its circumferential surface. The welded fixing portion 60 is welded and fixed to the outer circumference of one end of the housing 10 in an annular shape, thereby forming an annular shape along the circumferential direction on the circumferential surface of the blocking member 12. In addition, a gas ejection port 11 is provided on the circumferential wall near the end of the housing 10 on the side where the blocking member 12 is mounted. The gas ejection port 11 is a hole for ejecting the gas generated inside the gas generator 100 to the outside, and a plurality of gas ejection ports 11 are provided along the circumferential direction and axial direction of the housing 10.

[0025] The blocking member 12 is a member made of metal such as stainless steel, steel, aluminum alloy, or stainless steel alloy, and is composed of a substantially disk-shaped member having a predetermined thickness.

[0026] like Figure 1 and Figure 2As shown, the holder 20 is fixed to one end of the housing 10 on the ignition chamber 19 side, and has: a first forming portion having a holding portion 26 for holding the igniter 50 on the inner side of the housing 10; and a second forming portion 20b having a fitting portion 21 on the side opposite to the holding position of the igniter 50, into which a connector (not shown) for energizing the igniter 50 can be fitted. In addition, the holder 20 is a substantially cylindrical member made of metal such as stainless steel, steel, aluminum alloy or stainless steel alloy.

[0027] In addition, if Figure 3 As shown, before welding and fixing, the first forming portion 20a has: a side portion 22 for clamping the inner wall of the housing 10 and the end of the side cover 51 on the igniter 50 side; and a positioning portion 23 for positioning the end of the housing 10 on the igniter 50 side and the end of the side cover 51 on the igniter 50 side before welding and fixing. The outer diameter of the side portion 22 is formed to be smaller than the outer diameter of the second forming portion 20b. In addition, the positioning portion 23 is also a portion that forms a step shape together with the side portion 22 and the side portion 24 of the second forming portion 20b before welding and fixing. In addition, the second forming portion 20b is integrally provided on the first forming portion 20a on the side of the first forming portion 20a opposite to the working gas generation chamber 17 side.

[0028] like Figure 1 to Figure 3 As shown, the side cover 51 has a bottom 51a, a tapered portion 51b having one end connected and fixed to the bottom 51a, a first cylindrical portion 51c having one end connected and fixed to the other end of the tapered portion 51b, an igniter abutment portion 51d having one end connected and fixed to the other end of the first cylindrical portion 51c, and a second cylindrical portion 51e having one end connected and fixed to the other end of the igniter abutment portion 51d. The side cover 51 is a directional component that can collect the flame ejected from the front end of the igniter 50 by using the tapered portion 51b and guide the direction of the flame to the working gas generating chamber 17 side when the bottom 51a breaks during operation. In addition, a fragile portion (a recessed portion provided on the outer surface, etc.) can also be formed on the bottom 51a so that the bottom 51a is easily broken during operation.

[0029] In addition, in order to make the bottom 51a break during operation, the diameter of the bottom 51a and the angle of the tapered portion 51b relative to the axial direction of the first cylindrical portion 51c can be appropriately changed according to the output or size of the igniter 50, the material (stainless steel, steel, aluminum alloy or stainless steel alloy, etc.) used for the side cover 51, etc. For example, the diameter of the bottom 51a and the angle of the tapered portion 51b relative to the axial direction of the first cylindrical portion 51c can be as follows: Figures 4 to 6 The following is an example of Figures 4 to 6The following description is provided, and the symbols with the same number in the last two digits are the same parts, so the description is sometimes omitted. In addition, about the parts not particularly described, since they are the same as the present embodiment, the description is sometimes omitted.

[0030] exist Figure 4 , the angle of the tapered portion 151b relative to the axial direction of the first cylindrical portion 151c is 25°, and the diameter (ΦD) of the bottom portion 151a can be determined by various factors such as the angle of the tapered portion 151b relative to the axial direction of the first cylindrical portion 151c, the diameter of the first cylindrical portion 151c, the distance from the first cylindrical portion 151c to the bottom portion 151a, the output or size of the igniter, and the material used for the side cover 151. For example, the diameter (ΦD) of the bottom portion 151a can also be formed to any size of 4 mm to 5 mm.

[0031] In addition, Figure 5 In the embodiment, the angle of the tapered portion 251b relative to the axial direction of the first cylindrical portion 251c is 45°. Figure 6 In the embodiment, the angle of the tapered portion 351b relative to the axial direction of the first cylindrical portion 351c is 60°. Figure 5 and Figure 6 The diameter of the bottom 251a, 351a of the side cover 251, 351 is shown as Figure 4 The same is true for the side cover 151 shown, and can be determined by various factors such as the angle of the tapered portion relative to the axial direction of the first cylindrical portion, the diameter of the first cylindrical portion, the distance from the first cylindrical portion to the bottom, the output or size of the igniter, the material used for the side cover, etc.

[0032] In addition, Figures 4 to 6 Alternatively, the diameter of the bottom portion 51a may be set constant, and the axial angle of the tapered portion 51b relative to the first cylindrical portion 51c may be appropriately changed according to various factors such as the output of the igniter 50 and the material used in the side cover 51.

[0033] The tapered portion 51 b is a portion formed so as to decrease in diameter from the working gas generation chamber 17 side toward the filter chamber 18 side (the other axial end side of the housing 10 ).

[0034] The first tubular portion 51 c is a directional portion capable of directing the flame toward the working gas production chamber 17 , and is a tubular portion having an inner diameter that is the same as or substantially the same as the outer diameter of the squib cup 50 a of the igniter 50 .

[0035] like Figure 1 and Figure 2 As shown, the igniter contact portion 51 d is a portion for contacting the igniter 50 and being clamped and fixed together with the holder 20 .

[0036] like Figure 1 and Figure 2 As shown, the second cylindrical portion 51e is a cylindrical portion, and in a state where it is clamped by the inner wall of the housing 10 and the side portion 22, the end portion is welded and fixed to the housing 10 and the retainer 20 in the welding fixing portion 62. The welding fixing portion 62 is at a position corresponding to the side portion 22 covered by the side cover 51 (in this embodiment, the end portion of the side portion 22 on the retainer 20 side), Figure 3 The welding process is performed at the portion 62A along the circumferential direction of the housing 10, thereby Figure 2 As shown in FIG. 1 , the welding fixing portion 62 is formed into an annular shape along the circumferential direction of the housing 10. By the welding fixing portion 62, the air flow path between the inside and outside of the working gas generating chamber 17 is limited compared with the past. Figure 3 As shown, the end of the second cylindrical portion 51e is a portion that abuts against the positioning portion 23 before being fixed by welding.

[0037] like Figure 1 As shown, an igniter 50 serving as an ignition device for the gas generating agent 30 is provided at one axial end portion of the housing 10 (i.e., a portion close to the retainer). In addition, the igniter 50 and the retainer 20 to which the igniter 50 is fixed function as an ignition device for generating a flame, and the flame is used to burn the granular gas generating agent 30 described later.

[0038] like Figure 1 and Figure 2 As shown, the igniter 50 is inserted into the holding portion 26 of the first molded portion 20a and fixed to the holder 20 side by the side cover 51. More specifically, as described above, the end of the side cover 51 is welded and fixed to the housing 10 and the holder 20, so that the igniter abutment portion 51d of the side cover 51 is clamped and fixed to the bracket 20 (particularly the holding portion 26).

[0039] More specifically, the igniter 50 includes a base frame through which a pair of terminal pins 52 are inserted and held, and a squib cup 50a mounted on the base frame. A resistor (bridge wire) is mounted in such a manner as to connect the front end of the terminal pins 52 inserted into the squib cup 50a, and an ignition powder is filled in the squib cup 50a in such a manner as to surround or contact the resistor. As the resistor, a nickel-chromium alloy wire or the like is generally used, and as the ignition powder, ZPP (zirconium / potassium perchlorate), ZWPP (zirconium / tungsten / potassium perchlorate), lead trioctanoate, or the like is generally used. In addition, in the squib cup 50a, not only the ignition powder but also the transfer powder can be filled. As the transfer powder that can be set together with the ignition powder, a composition composed of a metal / oxidant represented by boron / potassium nitrate, a composition composed of titanium hydride / potassium perchlorate, or a composition composed of boron / 5-aminotetrazole / potassium nitrate / molybdenum trioxide, or the like can be used. The squib cup is generally made of metal or resin.

[0040] When a collision is detected, a predetermined amount of current flows to the resistor via the terminal pin 52. When a predetermined amount of current flows through the resistor, Joule heat is generated in the resistor, and the ignition charge begins to burn due to the heat. The high-temperature flame generated by the combustion ruptures the squib cup 50a containing the ignition charge. When a nickel-chromium alloy wire is used as the resistor, the time from the current flowing through the resistor to the igniter 50 operating is less than 2 milliseconds.

[0041] like Figure 1 As shown, the inner space of the housing 10 is provided with a working gas generating chamber 17 filled with a gas generating agent 30, a filter chamber 18 containing a filter 40, and an ignition chamber 19 containing a coil spring 35. The working gas generating chamber 17 and the filter chamber 18 are separated by a partition member 31.

[0042] On the working gas generation chamber 17 side of the partition member 31 described later, an AI agent 32 having an automatic ignition (AI) function that automatically ignites independently of the operation of the igniter 50 and the gas generating agent 30 are disposed.

[0043] like Figure 1 As shown, the gas generator 30 is arranged between the coil spring 35 and the cover member 33, and is an integrally molded product that generates gas by igniting and burning the flame generated by the ignition of the igniter 50. In addition, the gas generator 30 is usually formed as a molded body containing a fuel, an oxidant and an additive. As a fuel, for example, a triazole derivative, a tetrazole derivative, a guanidine derivative, an azodicarbonamide derivative, a hydrazine derivative, or a combination thereof can be used. Specifically, for example, nitroguanidine, guanidine nitrate, cyanoguanidine, 5-aminotetrazole, etc. are preferably used. In addition, as an oxidant, for example, alkaline metal hydroxides such as alkaline copper nitrate or alkaline copper carbonate, perchlorates such as ammonium perchlorate or potassium perchlorate, nitrates containing cations selected from alkali metals, alkaline earth metals, transition metals, and ammonia can be used. As nitrates, for example, sodium nitrate and potassium nitrate are preferably used. In addition, as additives, adhesives, slag forming agents, or combustion regulators can be cited. As the binder, for example, cellulose derivatives such as hydroxypropylene methylcellulose, metal salts of carboxymethyl cellulose, stearates and other organic binders, synthetic hydroxy talc, acid clay and other inorganic binders can be preferably used. As the slag-forming agent, silicon nitride, silicon dioxide, acid clay and the like can be preferably used. In addition, as the combustion regulator, metal oxides, ferrosilicon, activated carbon, graphite and the like can be preferably used.

[0044] like Figure 1As shown, in the ignition chamber 19, the coil spring 35 is wound in a spiral shape along the inner wall of the housing 10 opposite to the outer periphery of the side cover 51 in a manner similar to a cylindrical shape in overall appearance. In addition, the coil spring 35 is arranged so that one end abuts against the outer surface of the side cover 51 and the other end abuts against the gas generating agent 30 to apply elastic force to the gas generating agent 30. By this applied force, the gas generating agent 30 is fixed in the housing 10 in a manner of being sandwiched by the wound spring 35 and the cover member 33.

[0045] Since the AI ​​agent 32 having the AI ​​function automatically ignites at a lower temperature than the gas generator 30, in the event of a fire or the like in a vehicle equipped with an airbag device or the like in which the gas generator 100 is assembled, abnormal operation of the gas generator 100 due to external heating can be prevented. As a result, in the event of a fire or the like in a vehicle equipped with an airbag device or the like in which the gas generator 100 is assembled, the gas generator 30 can be prevented from burning before the AI ​​agent 32 automatically ignites. In addition, the cover member 33 is a disc-shaped member made of metal or alloy, and can be any member as long as it can separate the AI ​​agent 32 and the gas generator 30 and prevent them from contacting each other. For example, a plurality of holes may be provided, or no holes may be provided.

[0046] like Figure 1 and Figure 2 As shown, the partition member 31 is roughly bowl-shaped, and although not shown, a cut line (score) is provided near the center of the bottom so that it is easy to break when a specified pressure is applied. In addition, the side surface of the partition member 31 is welded and fixed in a ring shape along the circumference of the housing 10 in the welding fixing portion 61.

[0047] like Figure 1As shown, the filter chamber 18 is connected to the outside via the gas ejection port 11 provided on the peripheral wall of the housing 10. In addition, a filter 40 composed of a cylindrical member having a substantially cylindrical space 40a at the center is housed in the filter chamber 18. In addition, if a filter 40 composed of such a cylindrical member is used, the flow resistance of the working gas flowing in the filter chamber 18 during operation can be suppressed to a low level, and efficient gas circulation can be achieved. The filter 40 can be, for example, a member compacted by winding or punching a wire or mesh material made of a metal such as stainless steel or steel. Specifically, a metal wire mesh of an interlaced stockinette stitch, a plain woven metal wire mesh, or an aggregate of a crimped woven metal wire is used. The filter 40 acts as a cooling device for cooling the gas generated in the working gas generating chamber 17 by taking away the high temperature heat of the gas when passing through the filter 40, and acts as a removal device for removing residues contained in the gas. Here, as a modification of the filter 40, a filter having a labyrinth-shaped flow path formed by combining substantially cylindrical or mortar-shaped parts made of metal may be used. This allows the advancing direction of the working gas to be changed in various directions, thereby enabling the gas to be cooled and the residue to be removed.

[0048] In addition, a female connector (not shown) is mounted on the second forming portion 20b. The female connector is a portion to which a male connector of a wiring harness is connected, and the male connector of the wiring harness transmits a signal from a collision detection device that is separately provided from the gas generator 100. A retainer (not shown) is mounted on the female connector. The retainer is mounted to prevent the cylinder-type gas generator 100 from malfunctioning due to electrostatic discharge or the like during transportation of the gas generator 100, and in the assembly stage of the airbag device, the male connector of the wiring harness is inserted into the female connector to release the contact with the terminal pin 52.

[0049] Next, the operation of the gas generator 100 when it is in operation will be described. When a vehicle equipped with an airbag device equipped with the gas generator 100 in this embodiment collides, the collision is detected by a collision detection device separately provided on the vehicle, and based on this, the igniter 50 is operated. When the igniter 50 is operated, the pressure in the igniter 50 increases due to the combustion of the ignition powder, thereby the front end of the detonation cup 50a of the igniter 50 is broken, and the flame flows out from the front end of the detonation cup 50a of the igniter 50 to the inside of the side cover 51.

[0050] The flames flowing in like this are gathered by the tapered portion 51b of the side cover 51, and the bottom 51a of the side cover 51 is cracked, and the gas generating agent 30 in the container 34 is ignited and burned, thereby generating a large amount of gas. At this time, since the flames are concentrated, the flames are easily ejected to the inner side (filter chamber 18 side) of the working gas generating chamber 17. The pressure in the working gas generating chamber 17 is increased by the combustion of the gas generating agent 30, thereby cracking the partition member 31, and the gas flows into the filter chamber 18. In addition, the return portion of the partition member 31, which is roughly bowl-shaped, can prevent the gas from flowing into the space between the filter 40 and the inner wall of the housing 10, thereby preventing the gas from being released to the outside without passing through the filter 40. In this way, the gas flowing into the filter chamber 18 is cooled to a predetermined temperature via the filter 40. A large amount of the cooled gas is ejected from the gas ejection port 11 to the outside of the gas generator 100. The gas ejected from the gas ejection port 11 is guided to the inside of the airbag, causing the airbag to inflate and deploy.

[0051] (Main Features of Gas Generator 100)

[0052] According to the present embodiment, by forming the weld fixing portion 62 which is easy to work, the air flow path between the inside and outside of the working gas generating chamber 17 is restricted as compared with the past. Therefore, it is possible to provide a gas generator 100 which can suppress the gas generating agent 30 in the housing from being deteriorated due to moisture absorption as compared with the past and is easy to assemble.

[0053] In addition, since components such as O-rings and sealing materials are not required, the number of components can be reduced compared to conventional devices.

[0054] The embodiments of the present invention are described above based on the drawings, but it should be understood that the specific structure is not limited to these embodiments. The scope of the present invention is indicated by the claims rather than the description of the above embodiments, and includes all changes within the meaning and scope equivalent to the claims.

[0055] In the above embodiment, the side cover 51 is welded near the end to form the welded portion 62, but the present invention is not limited thereto. For example, the middle portion of the second cylindrical portion 51e of the side cover 51 and the side surface portion 22 of the housing 10 and the holder 20 may be welded.

[0056] Furthermore, the second cylindrical portion 51e of the side cover 51 does not need to be long enough to contact the positioning portion 23. However, in this case, the end or middle portion of the second cylindrical portion 51e of the side cover 51 needs to be firmly welded to the housing 10 and the side surface portion 22 of the holder 20.

[0057] Description of Reference Numerals

[0058] 10 Housing

[0059] 11 Gas outlet

[0060] 12 Blocking parts

[0061] 17 Working gas generation chamber

[0062] 18 Filter Chamber

[0063] 19 Ignition Chamber

[0064] 20 Retaining parts

[0065] 20a First forming part

[0066] 20b Second formation part

[0067] 21 Chimeric part

[0068] 22 Side face

[0069] 23 Positioning unit

[0070] 24 Side face

[0071] 26. Maintaining part

[0072] 30 Gas generating agent

[0073] 31 Separator

[0074] 32 AI agent

[0075] 33 Cover parts

[0076] 34 Storage Container

[0077] 35 Coil spring

[0078] 40 Filters

[0079] 40a Space

[0080] 50 Ignition

[0081] 50a Exploding Pipe Cup

[0082] 51, 151, 251, 351 side cover

[0083] 51a, 151a, 251a, 351a bottom

[0084] 51b, 151b, 251b, 351b tapered part

[0085] 51c, 151c, 251c, 351c first cylindrical part

[0086] 51d, 151d, 251d, 351d igniter contact portion

[0087] 51e, 151e, 251e, 351e 2nd cylindrical part

[0088] 52 Terminal pin

[0089] 60, 61, 62 Welding fixing parts

[0090] 100 Gas Generator

Claims

1. A gas generator, characterized in that: have: A casing of an elongated cylindrical shape, which contains a working gas generating chamber in which a working gas is generated by combustion of a gas generating agent, and a filter chamber in which a filter is accommodated through which the working gas generated in the working gas generating chamber passes; A gas generating agent ignition device, which contains ignition powder and is arranged at one axial end of the housing, and can ignite and burn the gas generating agent in the working gas generating chamber; a retainer fixed to one axial end of the housing, having a substantially cylindrical first forming portion, the first forming portion having a holding portion for holding the gas generating agent ignition device on the inner side of the housing, and a substantially cylindrical second forming portion, the second forming portion being integrally provided on the first forming portion on the side opposite to the working gas generating chamber side of the first forming portion, and having a fitting portion capable of fitting a connector for energizing the gas generating agent ignition device on the side opposite to the holding position of the gas generating agent ignition device; a side cover, which is a bottomed cylindrical member having a cylindrical portion, covering at least a portion of the working gas generation chamber side of the gas generating agent ignition device and at least a portion of the side surface of the first forming portion, and the cylindrical portion is provided in a manner of being sandwiched by the inner wall of the housing and the side surface of the first forming portion, At least a portion of the shell at a position corresponding to the side surface of the first forming portion covered by the side cover, a portion of the side cover corresponding to the portion, and a portion of the side surface of the retaining member corresponding to the portion are welded and fixed in an annular shape along the circumference of the shell.

2. The gas generator according to claim 1, characterized in that The welding and fixing is performed along the position of the end portion of the side cover on the retainer side.

3. The gas generator according to claim 1 or 2, characterized in that: The end portion of the side cover on the working gas generation chamber side is formed with: bottom surface; and A tapered portion connected to the bottom surface portion and having a reduced diameter toward the other end portion side in the axial direction of the housing.

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