Gas generator and method for manufacturing the same

Abstract

To stabilize quality by suppressing dimensional variations after assembly. [Solution] The method for manufacturing a gas generator comprises the steps of: inserting a partition member 50 including a partition wall 51 into a peripheral wall 10; fixing the partition member 50 to a housing; inserting a filter 80 into the peripheral wall 10; inserting a closing member into the peripheral wall 10; and crimping the peripheral wall 10 so that each of the pair of axial end faces of the filter 80 is in pressure contact with the closing member and the main surface 51a of the partition wall 51 on the filter 80 side, and the crimping portion is in pressure contact with the closing member, thereby fixing the closing member and the filter 80 to the housing. In the step of inserting the filter 80 into the peripheral wall 10, if the inner diameter of the peripheral wall 10, the outer diameter and inner diameter of the filter 80, and the diameter of the outer edge of the main surface 51a are H, F1, F2, and R respectively, then equations (1) and (2) are satisfied. F1 <H···(1) (H-F1)≦(HR) / 2≦(F1-F2) / 2···(2)

Description

Technical Field

[0001] The present invention relates to a gas generator incorporated in an airbag device as an occupant protection device installed in automobiles and the like, and a method for manufacturing the same, and particularly relates to a so-called cylinder-type gas generator having an elongated columnar outer shape, which is suitably incorporated in a side airbag device and the like, and a method for manufacturing the same.

Background Art

[0002] Conventionally, from the viewpoint of protecting occupants of automobiles and the like, airbag devices that are occupant protection devices have become widespread. Airbag devices are installed for the purpose of protecting occupants from impacts generated at the time of a vehicle collision or the like, and by inflating and deploying the airbag instantaneously at the time of a vehicle collision or the like, the airbag acts as a cushion to receive the occupant's body.

[0003] A gas generator is a device that is incorporated in this airbag device, ignites an igniter by energization from a control unit at the time of a vehicle collision or the like, burns a gas generating agent with the flame generated in the igniter to generate a large amount of gas instantaneously, and thereby inflates and deploys the airbag.

[0004] Gas generators have various configurations based on specifications such as installation position and output for vehicles and the like. One of them is referred to as a cylinder-type gas generator. The cylinder-type gas generator has an elongated columnar outer shape, and is suitably incorporated in side airbag devices, curtain airbag devices, knee airbag devices, seat cushion airbag devices and the like.

[0005] Usually, in a cylinder-type gas generator, an igniter is assembled to one axial end of a housing, a gas generating agent storage chamber storing a gas generating agent is provided on the one end side, a filter chamber storing a cylindrical filter is provided on the other axial end side of the housing, and gas discharge ports are provided in the peripheral wall portion of the housing at the portion defining the filter chamber.

[0006] In a cylinder-type gas generator configured in this way, the gas generated in the gas generating agent containment chamber flows into the filter chamber along the axial direction of the housing, passes through the inside of the filter, and the gas that has passed through the filter is ejected to the outside through the gas outlet.

[0007] One example of a document disclosing a cylinder-type gas generator with such a configuration is Japanese Patent Application Publication No. 2023-112954 (Patent Document 1). In the cylinder-type gas generator disclosed in Patent Document 1, the filter is fixed inside the housing in a state where it is sandwiched in the axial direction of the housing by a partition member and a closing member.

[0008] In detail, the closure member is pressed inward in the axial direction of the housing by the crimped portion of the housing. The pressed closure member abuts against one of the pair of axial end faces of the filter, pressing the filter inward in the axial direction of the housing. The other of the pair of axial end faces of the pressed filter presses against the partition member.

[0009] The partition member has a disc-shaped partition wall and an annular wall that is erected from the periphery of the partition wall and extends along the inner circumferential surface of the housing. The partition member configured in this way is fixed to the housing, for example, by welding the annular wall to the housing. The partition wall may deform due to being pressed by the axial end face of the filter as described above.

[0010] As described above, the periphery of the partition wall has higher rigidity than the rest of the partition wall due to the presence of the annular wall. Therefore, the amount of deformation of the partition wall when the axial end face of the filter presses against the rest of the partition wall is greater than the amount of deformation of the partition wall when the axial end face of the filter presses against the periphery of the partition wall. When the amount of deformation of the partition wall increases, the distance between the closing member and the crimping portion also increases accordingly. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 2023-112954 [Overview of the project] [Problems that the invention aims to solve]

[0012] In the case of a cylinder-type gas generator, if a filter with an outer diameter smaller than the inner diameter of the housing is used, the radial position of the filter after assembly tends to vary from product to product. Due to this variation in the filter's position, the distance between the sealing member and the crimping portion may also vary from product to product. Since this distance is a factor related to the pressure resistance performance of the housing, it is desirable to suppress such variations as much as possible.

[0013] Therefore, the present invention has been made in view of the above-mentioned problems, and aims to provide a gas generator and a method for manufacturing the same in which quality is stabilized by suppressing dimensional variations after assembly. [Means for solving the problem]

[0014] A method for manufacturing a gas generator according to the present invention includes the steps of: inserting a partition member having a disc-shaped partition wall portion including a pair of main surfaces and an annular wall portion erected from the periphery of the partition wall portion into the circumferential wall portion such that the pair of main surfaces are substantially perpendicular to the axial direction of the cylindrical circumferential wall portion of the housing; fixing the partition member to the housing by welding the annular wall portion to the circumferential wall portion while the partition member is inserted into the circumferential wall portion; inserting a cylindrical filter into the circumferential wall portion such that the axial direction of the filter is substantially parallel to the axial direction of the circumferential wall portion and is located on the opposite side from the side where the annular wall portion is located when viewed from the partition wall portion; and moving the filter in the axial direction of the circumferential wall portion The method comprises the steps of: inserting the closing member into the peripheral wall portion so as to sandwich it between the partition member and the closing member; and, with the partition member fixed to the housing and the closing member inserted into the peripheral wall portion, crimping the peripheral wall portion so as to form a crimped portion that is reduced in diameter toward the radially inward, thereby causing the axial end face of the filter on the closing member side to be in pressure contact with the closing member, the axial end face of the filter on the partition member side to be in pressure contact with the main surface of the partition wall portion located on the filter side of the pair of main surfaces, and fixing the closing member and the filter to the housing while the crimped portion is in pressure contact with the closing member. In the process of inserting the filter into the peripheral wall, if the inner diameter of the peripheral wall is H, the outer diameter of the filter is F1, the inner diameter of the filter is F2, and the diameter of the outer edge of the main surface located on the filter side of the pair of main surfaces of the partition wall is R, then the following equations (1) and (2) are satisfied. F1 <H···(1) (H-F1)≦(HR) / 2≦(F1-F2) / 2···(2)

[0015] In the method for manufacturing a gas generator according to the present invention described above, the connecting surface that connects the main surface of the partition wall located on the filter side of the pair of main surfaces of the partition wall to the outer circumferential surface of the annular wall may be a curved surface with a radius of curvature of 1 mm or more.

[0016] A gas generator according to the present invention comprises a housing, a partition member, an igniter, and a blocking member. The housing has a cylindrical peripheral wall portion with one end and the other end closed in the axial direction, and includes a gas generating agent chamber containing a gas generating agent and a filter chamber where a cylindrical filter is arranged. The partition member is inserted into the peripheral wall portion so that the gas generating agent chamber is located on the side of the one end and the filter chamber is located on the side of the other end, thereby partitioning the space inside the housing in the axial direction of the peripheral wall portion. The igniter is assembled to the one end. The blocking member closes the other end by being inserted into the peripheral wall portion. The filter is arranged in the filter chamber so that the axial direction of the filter is substantially parallel to the axial direction of the peripheral wall portion. The partition member has a disc-shaped partition portion and an annular wall portion. The partition portion includes a pair of main surfaces substantially perpendicular to the axial direction of the peripheral wall portion. The annular wall portion is erected from the periphery of the partition wall portion toward the one end and extends along the inner circumferential surface of the peripheral wall portion. The partition member is fixed to the housing by welding the annular wall portion and the peripheral wall portion together. The peripheral wall portion has a crimped portion that is tapered toward the radially inward direction. The crimped portion, the closing member, the filter, and the partition member are positioned in this order from the other end to the one end in the axial direction of the peripheral wall portion. The axial end face of the filter on the closing member side is in pressure contact with the closing member. The axial end face of the filter on the partition member side is in pressure contact with the main surface located on the other end side of the pair of main surfaces of the partition wall portion. The crimped portion is in pressure contact with the closing member. The gas generator according to the present invention satisfies the following equations (1) and (2) when the inner diameter of the peripheral wall is H, the outer diameter of the filter is F1, the inner diameter of the filter is F2, and the diameter of the outer edge of the main surface located on the other end side of the pair of main surfaces of the partition wall is R. F1 <H···(1) (H-F1)≦(HR) / 2≦(F1-F2) / 2···(2) [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a gas generator with stabilized quality by suppressing dimensional variations after assembly, and a method for manufacturing the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] [Figure 1] This is a schematic diagram of the cylinder-type gas generator according to the embodiment. [Figure 2] This is an enlarged cross-sectional view near the igniter of the cylinder-type gas generator shown in Figure 1. [Figure 3] This is an enlarged cross-sectional view near the partition member of the cylinder-type gas generator shown in Figure 1. [Figure 4] This is a schematic cross-sectional view for explaining the outer peripheral edge of the first main surface of the partition wall portion of the partition member. [Figure 5] This is a flow chart showing the assembly procedure of the cylinder-type gas generator shown in Figure 1. [Figure 6] This is a schematic cross-sectional view for explaining the step shown in Figure 5. [Figure 7] This is a schematic cross-sectional view for explaining the step shown in Figure 5. [Figure 8] This is a schematic cross-sectional view for explaining the step shown in Figure 5. [Figure 9] This is a schematic cross-sectional view for explaining the step shown in Figure 5. [Figure 10] This is one aspect of the position of the filter in the radial direction of the peripheral wall portion, which is assumed in the step shown in Figure 5. [Figure 11] This is another aspect of the position of the filter in the radial direction of the peripheral wall portion, which is assumed in the step shown in Figure 5. MODE FOR CARRYING OUT THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiments shown below exemplify the case where the present invention is applied to a cylinder-type gas generator incorporated in a side airbag device. In addition, in the embodiments shown below, the same or common parts are denoted by the same reference numerals in the drawings, and descriptions thereof will not be repeated.

[0020] (Embodiment) <A. Configuration of Cylindrical Gas Generator> Figure 1 is a schematic diagram of the cylindrical gas generator according to the embodiment. Figure 2 is an enlarged cross-sectional view in the vicinity of the igniter of the cylindrical gas generator shown in Figure 1. Figure 3 is an enlarged cross-sectional view in the vicinity of the partition member of the cylindrical gas generator shown in Figure 1. Figure 4 is a schematic cross-sectional view for explaining the diameter of the outer peripheral edge of the first main surface of the partition wall portion of the partition member. In detail, Figure 4(A) to Figure 4(C) are schematic cross-sectional views for explaining the diameter of the outer peripheral edge in each aspect of the partition member. First, the configuration of the cylindrical gas generator 1A according to the present embodiment will be described with reference to Figure 1 to Figure 4.

[0021] As shown in Figure 1 to Figure 3, the cylindrical gas generator 1A has an elongated columnar outer shape, and has an elongated substantially cylindrical housing with one end and the other end positioned in the axial direction closed. The housing includes a peripheral wall portion 10, a holder assembly 20, a closing member 30, and a partition member 50, among which the peripheral wall portion 10, the holder assembly 20, and the closing member 30 define the outer shell of the housing.

[0022] Inside the peripheral wall portion 10, the holder assembly 20, and the closing member 30 that define the outer shell of the housing, an igniter 40, a gas generating agent 60, an auto-ignition agent 61, a coil spring 70, a filter 80 and the like as internal components are accommodated, and in addition to these, the aforementioned partition member 50 which is also an internal component is arranged. Inside the housing, a gas generating agent accommodation chamber S1 in which the gas generating agent 60, the auto-ignition agent 61, and the coil spring 70 among the aforementioned internal components are accommodated, and a filter chamber S2 in which the filter 80 is accommodated are located.

[0023] The peripheral wall portion 10 is formed of an elongated cylindrical member having openings formed at both axial ends. One axial end portion 10a of the peripheral wall portion 10 is closed by the holder assembly 20. The other axial end portion 10b of the peripheral wall portion 10 is closed by the closing member 30.

[0024] The peripheral wall portion 10 may be made of a metal component such as stainless steel, iron or steel, aluminum alloy, or stainless alloy, or it may be made of a press-formed product formed into a cylindrical shape by press-working a rolled steel sheet, such as SPCE. The peripheral wall portion 10 may also be made of an electric resistance welded pipe, such as STKM.

[0025] In particular, when the peripheral wall portion 10 is constructed from a press-formed rolled steel sheet or an electric resistance welded pipe, the peripheral wall portion 10 can be formed more cheaply and easily compared to when metal components such as stainless steel or iron are used, and a significant reduction in weight is possible.

[0026] The holder assembly 20 is fixed to the peripheral wall portion 10 so as to close one of the axial open ends of the peripheral wall portion 10.

[0027] In detail, with the holder assembly 20 inserted into one of the open ends of the peripheral wall portion 10, a predetermined position of the peripheral wall portion 10 is reduced in diameter radially inward toward the holder assembly 20, and another predetermined position of the peripheral wall portion 10 is reduced in diameter radially inward toward the holder assembly 20. As a result, the holder assembly 20 is crimped and fixed to the peripheral wall portion 10. The holder assembly 20 may also be fixed to the peripheral wall portion 10 by welding or the like at or near the contact point with the peripheral wall portion 10.

[0028] As shown in Figures 1 and 2, the holder assembly 20 includes a first holder 20A made of metal, a second holder 20B made of resin, and a third holder 20C made of resin. When viewed as a whole, the holder assembly 20 consists of a substantially cylindrical member having a hollow portion extending along a direction parallel to the axial direction of the peripheral wall portion 10.

[0029] The first holder 20A is composed of a flat, substantially disc-shaped member having a through portion extending axially in its central part, and includes a cylindrical first body portion 21 and an annular projection 22 projecting outward from the outer circumferential surface of the first body portion 21. The annular projection 22 is provided at the end of the first body portion 21 on the gas generating agent containment chamber S1 side.

[0030] The first holder 20A has a concave first housing portion 21a at its axial end facing the gas generating agent housing chamber S1 in order to receive the igniter 40. The first housing portion 21a is connected to a through portion provided in the first holder 20A and defines a part of the hollow portion of the holder assembly 20 as described above. A crimping portion 21b is provided at the end of the first holder 20A facing the gas generating agent housing chamber S1, surrounding the first housing portion 21a. The crimping portion 21b is a part for crimping and fixing the igniter 40 to the first holder 20A.

[0031] A sealing member 28, such as an O-ring, is interposed between the first holder 20A and the igniter 40. As a result, the gap between the first holder 20A and the igniter 40 is filled by the sealing member 28, thereby sealing the gap.

[0032] The second holder 20B is composed of a substantially cylindrical member having a second housing portion 23a in the shape of a generally through hole extending axially in its central part, and includes a cylindrical second body portion 23 and a lid portion 26 provided to cover one end of the second housing portion 23a in the axial direction. The second holder 20B is positioned on the gas generating agent housing chamber S1 side when viewed from the first holder 20A, and is located adjacent to the first holder 20A.

[0033] The ignition unit 42 of the igniter 40 is housed in the second housing section 23a. That is, the second holder 20B is positioned to surround the ignition unit 42 of the igniter 40 held by the first holder 20A, so that the portion of the second body 23 of the second holder 20B closer to the first holder 20A surrounds the circumferential surface of the ignition unit 42. The ignition unit 42 will be described in detail later.

[0034] The lid portion 26 is located at the axial end of the second body portion 23 opposite to the first holder 20A side, at a predetermined distance from the ignition portion 42. The lid portion 26 is provided with a plurality of openings 26a. The maximum external dimension of each of these openings 26a, when viewed along the axial direction of the peripheral wall portion 10, is smaller than the minimum external dimension of the gas generating agent 60.

[0035] As a result, the second housing portion 23a, located on the side of the igniter 40 opposite to the base portion 41 when viewed from the ignition unit 42, is substantially closed by the cover portion 26 at a predetermined distance from the ignition unit 42. Consequently, the gas generating agent 60 is prevented from entering the second housing portion 23a, and the gas generating agent 60 is separated from the ignition unit 42 so that it is positioned at a distance. The base portion 41 will be described in detail later.

[0036] Thus, the second holder 20B functions as a directional member that directs the direction of travel of heat particles generated in the ignition unit 42 when the cylinder-type gas generator 1A is in operation, by filling the gap between the ignition unit 42 and the peripheral wall unit 10. In particular, the second body unit 23 of the second holder 20B has this function.

[0037] The third holder 20C is composed of a substantially cylindrical member having a third housing portion 27a in the shape of a through hole extending axially in its central part, and includes a cylindrical third body portion 27. The third holder 20C is positioned on the opposite side from the gas generating agent housing chamber S1 when viewed from the first holder 20A, and is located adjacent to the first holder 20A.

[0038] The third housing section 27a houses a pair of terminal pins 43 of the igniter 40. The third housing section 27a constitutes a portion for receiving the harness connection connector. The terminal pins 43 will be described in detail later.

[0039] Here, of the second body portion 23 of the second holder 20B, a plurality of protrusions 24 are provided on the inner circumferential surface of the portion that is compressed radially inward by the pressure contact of the first crimping portion 11 and that faces the outer circumferential surface of the ignition portion 42. When viewed along the axial direction of the second holder 20B, these plurality of protrusions 24 are arranged in a dotted line along the circumferential direction of the second body portion 23 and protrude toward the ignition portion 42. The first crimping portion 11 will be described in detail later.

[0040] The inner diameter of the second holder 20B (i.e., the diameter of the second housing portion 23a) is set to be slightly larger than the diameter of the ignition portion 42. The amount of protrusion of the multiple projections 24 is adjusted so that when the ignition portion 42 is inserted into the second body portion 23 of the second holder 20B, their tips make pressure contact with the outer surface of the ignition portion 42 with a relatively weak force.

[0041] Therefore, when the ignition unit 42 is pressed into the second body 23 and in the state after press-fitting, only the multiple protrusions 24 come into contact with the outer circumferential surface of the ignition unit 42, and in the parts other than those where these multiple protrusions 24 are provided, a gap is formed between the outer circumferential surface of the ignition unit 42 and the inner circumferential surface of the second body 23.

[0042] As a result, during and after press-fitting the ignition unit 42 into the second body 23, the majority of the area where the ignition unit 42 and the second body 23 face each other is separated by the gap, and only the tips of the multiple protrusions 24 make pressure contact with the ignition unit 42. Therefore, it is possible to minimize deformation of the ignition unit 42 while press-fitting it into the second body 23.

[0043] The first holder 20A is made of a metal component such as stainless steel, iron ore, aluminum alloy, or stainless alloy.

[0044] The material of the second holder 20B and the third holder 20C is not particularly limited, but suitable materials include nylon-based resins such as nylon 6, nylon 66, and those filled with glass filler, polyacetal (POM) resin, polycarbonate (PC) resin, polyphenylene sulfide (PPS) resin, polybutylene terephthalate (PBT) resin, etc. The second holder 20B and the third holder 20C may be made of the same material or different materials.

[0045] As shown in Figure 1, the closure member 30 is made up of a substantially disc-shaped member. The closure member 30 is fixed to the peripheral wall portion 10 so as to close the other axial open end of the peripheral wall portion 10. In detail, the closure member 30 is inserted into the open end of the peripheral wall portion 10 located on the side opposite to the side to which the holder assembly 20 of the peripheral wall portion 10 is fixed (i.e., the left open end in Figure 1), so that one axial end face of the closure member 30 is pressed against the filter 80, and the closure member 30 is crimped and fixed to the peripheral wall portion 10 by reducing the diameter of a predetermined position of the peripheral wall portion 10 radially inward toward the vicinity of the other axial end face of the closure member 30.

[0046] These crimping fixations are of a type called eight-way crimping, which reduces the diameter of the peripheral wall portion 10 almost uniformly toward the radially inward direction.

[0047] By performing this eight-way crimping, a third crimping portion 13 for fixing the closing member 30 is provided on the peripheral wall portion 10. As a result, the peripheral wall portion 10 and the closing member 30 come into direct contact, preventing any gaps from forming between them. The third crimping portion 13 is in pressure contact with the closing member 30.

[0048] Similarly, by performing eight-way crimping, the peripheral wall portion 10 is provided with a first crimping portion 11 and a second crimping portion 12 for fixing the holder assembly 20. As a result, the peripheral wall portion 10 and the holder assembly 20 come into direct contact, preventing any gaps from forming between them.

[0049] The crimping length, which is the axial distance of the peripheral wall portion 10 between the end face of the pair of axial end faces of the peripheral wall portion 10 on the side where the closing member 30 is located and the end face of the pair of axial end faces of the closing member 30 on the side where the end face of the peripheral wall portion 10 is located, is set to be considerably long. Accordingly, the peripheral wall portion 10 has a straight portion 10c that extends for a considerable length along the axial direction in the portion located on the end face side of the peripheral wall portion 10 than the third crimping portion 13. This makes it possible to improve the fixing strength of the closing member 30 to the peripheral wall portion 10 by the third crimping portion 13.

[0050] The blocking member 30 is made of a metal material such as stainless steel, iron or steel, aluminum alloy, or stainless steel alloy.

[0051] As shown in Figures 1 and 2, the igniter 40 is mounted to one axial end 10a of the peripheral wall portion 10 by being supported by the holder assembly 20. The igniter 40 is installed facing the internal space of the housing.

[0052] The igniter 40 is used to burn the gas generating agent 60 by generating a flame, and is also called a squib. The igniter 40 includes a base 41, an ignition unit 42, and a pair of terminal pins 43. The base 41 is the part that holds the ignition unit 42 and the pair of terminal pins 43, and at least one of the pair of terminal pins 43 is inserted through the base 41. The pair of terminal pins 43 are for electrically connecting the cylinder-type gas generator 1A to a control unit (not shown) of a vehicle or the like that is located outside.

[0053] The ignition unit 42 contains, inside, an igniter that generates a flame when ignited and burned during operation, and a resistor (bridge wire) for igniting the igniter. A pair of terminal pins 43 are connected to the ignition unit 42 to ignite the igniter.

[0054] In detail, the ignition unit 42 includes a cup-shaped squib cup, and the aforementioned resistor is attached to connect the tips of a pair of terminal pins 43 inserted into the squib cup, with an igniter loaded inside the squib cup so as to surround or be close to the resistor. A propellant charge may also be loaded inside the ignition unit 42 as needed.

[0055] Generally, nichrome wire or resistance wires made of alloys containing platinum and tungsten are used as resistors, and generally, ZPP (zirconium-potassium perchlorate), ZWPP (zirconium-tungsten-potassium perchlorate), and lead tricinate are used as igniters. Furthermore, compositions consisting of metal powder / oxidizing agents such as B / KNO3, B / NaNO3, and Sr(NO3)2, as well as compositions consisting of titanium hydride / potassium perchlorate and compositions consisting of B / 5-aminotetrazole / potassium nitrate / molybdenum trioxide are used as propellants.

[0056] When a collision is detected, a predetermined amount of current flows through the resistor via terminal pin 43. This current generates Joule heat in the resistor, causing the igniter to begin burning. The high-temperature thermal particles produced by the combustion cause the squib cup containing the igniter to rupture. The time from when current flows through the resistor until the igniter 40 activates is generally 2 milliseconds or less when a nichrome wire is used for the resistor.

[0057] The igniter 40 is assembled to the holder assembly 20 such that the ignition part 42 protrudes toward the inside of the housing. Therefore, when the igniter 40 is operated, the ignition charge is ignited, causing a crack in the squib cup, and the squib cup opens as a result of this crack.

[0058] As shown in Figures 1 and 3, a partition member 50 is inserted into the peripheral wall portion 10. The partition member 50 is a member that partitions the space inside the housing in the axial direction of the peripheral wall portion 10 such that the gas generating agent containment chamber S1 is located on the side of one end 10a in the axial direction of the peripheral wall portion 10 and the filter chamber S2 is located on the side of the other end 10b in the axial direction of the peripheral wall portion 10.

[0059] The partition member 50 has a partition wall portion 51 and an annular wall portion 52. The partition wall portion 51 is a disc-shaped portion including a first main surface 51a and a second main surface 51b that are substantially perpendicular to the axial direction of the peripheral wall portion 10. The annular wall portion 52 is a portion erected from the periphery of the partition wall portion 51 toward one end 10a of the peripheral wall portion 10. The annular wall portion 52 extends along the inner circumferential surface of the peripheral wall portion 10. The partition member 50 is arranged such that the first main surface 51a of the partition wall portion 51 abuts against the filter 80.

[0060] The annular wall portion 52 includes a contact portion 52a that abuts against the inner circumferential surface of the peripheral wall portion 10, and a spaced portion 52b that is positioned spaced apart from the inner circumferential surface of the peripheral wall portion 10, thereby creating a gap G between it and the inner circumferential surface of the peripheral wall portion 10. The contact portion 52a extends along a direction parallel to the circumferential direction of the peripheral wall portion 10. The gap G communicates with the filter chamber S2.

[0061] The contact portion 52a and the separation portion 52b are positioned adjacent to each other in the axial direction of the peripheral wall portion 10. More specifically, the separation portion 52b is provided continuously with the partition wall portion 51, and the contact portion 52a is provided continuously with the end of the pair of ends of the separation portion 52b in the axial direction that is opposite to the partition wall portion 51.

[0062] The separated portion 52b includes an inclined portion that slopes away from the inner circumferential surface of the peripheral wall portion 10 as it moves from one axial end 10a side to the other end 10b side of the peripheral wall portion 10 (i.e., as it moves from the side where the holder assembly 20 is located to the side where the closing member 30 is located), and a portion that is continuous with the end of the inclined portion located on the other end 10b side of the peripheral wall portion 10 and extends along a direction substantially parallel to the inner circumferential surface of the peripheral wall portion 10. The contact portion 52a is provided continuously with the end of the inclined portion located on the one end 10a side of the peripheral wall portion 10.

[0063] The partition member 50 is press-fitted into the interior of the peripheral wall 10 and fixed to the peripheral wall 10 by welding the annular wall 52 and the peripheral wall 10 together. Laser welding is used for welding the annular wall 52 and the peripheral wall 10. However, this welding is not limited to laser welding, and other welding methods such as electron beam welding or resistance welding can also be suitably used.

[0064] The welded joint 90 that welds the annular wall portion 52 and the peripheral wall portion 10 is provided extending along the circumferential direction of the peripheral wall portion 10. The welded joint 90 penetrates the peripheral wall portion 10 in its thickness direction and also penetrates the annular wall portion 52 in its thickness direction.

[0065] The welded joint 90 is provided on a portion of the separated portion 52b of the annular wall portion 52 and on the peripheral wall portion 10 opposite to the portion of the separated portion 52b. With this configuration, at least a portion of the gap G between the peripheral wall portion 10 and the separated portion 52b is filled by the welded joint 90. As a result, the gap G is sealed by the welded joint 90, and sealing performance in that portion is ensured.

[0066] Furthermore, as described above, since the welded portion 90 is provided on a part of the separated portion 52b of the annular wall portion 52 and on the peripheral wall portion 10 opposite to the part of the separated portion 52b, at least a part of the welded portion 90 faces the gap G. This makes it possible to suppress the occurrence of blowholes in the welded portion where the partition member 50 and the housing are welded.

[0067] A score 51a1 is provided on the first main surface 51a of the partition wall 51. The score 51a1 is intended to cause the partition wall 51 to rupture and form an opening as the internal pressure of the gas generating agent containment chamber S1 increases due to the combustion of the gas generating agent 60, and is composed of, for example, a plurality of grooves arranged radially and intersecting each other. The score 51a1 is provided on the part of the filter 80 that faces the cavity 81.

[0068] The connecting surface J (see Figure 4(A)) that connects the first main surface 51a of the partition wall portion 51 and the outer peripheral surface of the annular wall portion 52 may be a curved surface. This suppresses unintended deformation of the partition wall portion 51 caused by stress concentration near the outer peripheral edge of the first main surface 51a when the first main surface 51a of the partition wall portion 51 is pressed against the axial end face of the filter 80 during assembly. This effect is more pronounced when the connecting surface J is a curved surface with a radius of curvature of 1 mm or more.

[0069] The connecting surface J may be a surface that is bent with respect to both the first main surface 51a of the partition wall 51 and the outer circumferential surface of the annular wall 52. Furthermore, it is not necessary for a connecting surface J to be provided between the first main surface 51a of the partition wall 51 and the outer circumferential surface of the annular wall 52; the first main surface 51a of the partition wall 51 and the outer circumferential surface of the annular wall 52 may be directly connected.

[0070] The material of the partition member 50 is not particularly limited, but it is made of metal such as stainless steel, iron or steel, aluminum alloy, or stainless alloy.

[0071] Here, the periphery of the partition wall portion 51 has higher rigidity than the rest of the partition wall portion 51 due to the presence of the annular wall portion 52. The periphery of the partition wall portion 51 refers to the portion including the outer peripheral edge of the first main surface 51a of the partition wall portion 51.

[0072] As shown in Figure 4(A), in an embodiment of the partition member 50 in which the connecting surface J is a curved surface, the outer edge of the first main surface 51a corresponds to the portion of the planar part of the first main surface 51a that is connected to the connecting surface J. This embodiment is consistent with the embodiment of the partition member 50 in this embodiment.

[0073] As shown in Figure 4(B), in an embodiment of a partition member 50 in which the connecting surface J is a surface bent with respect to both the first main surface 51a of the partition wall portion 51 and the outer peripheral surface of the annular wall portion 52, the outer peripheral edge of the first main surface 51a corresponds to the portion of the planar part of the first main surface 51a that is connected to the connecting surface J.

[0074] As shown in Figure 4(C), in an embodiment of a partition member 50 in which the first main surface 51a of the partition wall 51 and the outer peripheral surface of the annular wall 52 are directly connected, the outer peripheral edge of the first main surface 51a corresponds to the portion of the planar part of the first main surface 51a that is connected to the annular wall 52.

[0075] The diameter R of the outer peripheral edge of the first main surface 51a of the partition wall portion 51 in each of the above-described embodiments of the partition member 50 is as shown in Figures 4(A) to 4(C).

[0076] As shown in Figures 1 and 3, the space inside the housing, sandwiched between the holder assembly 20 and the partition member 50 (i.e., the gas generating agent storage chamber S1), contains the gas generating agent 60, the auto-ignition agent 61, and the coil spring 70.

[0077] The coil spring 70 is positioned on the side of the gas generating agent containment chamber S1 where the partition member 50 is located. The gas generating agent 60 is positioned between the holder assembly 20 and the coil spring 70. The auto-ignition agent 61 is positioned between the partition wall 51 and the coil spring 70 so as to abut against the partition wall 51 of the partition member 50.

[0078] The gas generating agent 60 is an agent that generates gas by being ignited and burned by the thermal particles produced when the igniter 40 is activated. It is preferable to use a non-azide gas generating agent 60, and the gas generating agent 60 is generally composed of a molded body containing fuel, an oxidizer, and an additive.

[0079] As fuels, for example, triazole derivatives, tetrazole derivatives, guanidine derivatives, azodicarbonamide derivatives, hydrazine derivatives, etc., or combinations thereof can be used. Specifically, for example, nitroguanidine, guanidine nitrate, cyanoguanidine, 5-aminotetrazole, etc., are preferably used.

[0080] Suitable oxidizing agents include basic metal salts such as basic copper nitrate and basic copper carbonate, perchlorates such as ammonium perchlorate and potassium perchlorate, and nitrates containing cations selected from alkali metals, alkaline earth metals, transition metals, and ammonia. Suitable nitrates include sodium nitrate and potassium nitrate.

[0081] Examples of additives include binders, slag-forming agents, and combustion modifiers. Suitable binders include organic binders such as metal salts of carboxymethylcellulose and stearates, and inorganic binders such as synthetic hydrotalcite and acid clay. Suitable slag-forming agents include silicon nitride, silica, and acid clay. Suitable combustion modifiers include metal oxides, ferrosilicon, activated carbon, and graphite.

[0082] The molded body of the gas generating agent 60 can take various shapes, such as granular, pelletized, cylindrical, or disc-shaped forms. In the case of cylindrical forms, perforated molded bodies with through holes inside (e.g., single-hole cylindrical or multi-hole cylindrical shapes) are also used. These shapes are preferably selected appropriately according to the specifications of the airbag device into which the cylinder-type gas generator 1A is incorporated. For example, it is preferable to select a shape in which the gas generation rate changes over time during the combustion of the gas generating agent 60, or to select the optimal shape according to the specifications. In addition to the shape of the gas generating agent 60, it is also preferable to appropriately select the size and filling amount of the molded body, taking into consideration the linear combustion rate and pressure index of the gas generating agent 60.

[0083] The coil spring 70 is provided to prevent the gas generating agent 60, which is made of a molded body, from being crushed by vibration or the like, and is constructed by winding a metal wire. The coil spring 70 has a spring portion 71, a first pressing portion 72a, and a second pressing portion 72b.

[0084] The spring portion 71 consists of a metal wire wound in a spiral shape. The first pressing portion 72a is provided at the end of the spring portion 71 on the gas generating agent 60 side. The first pressing portion 72a is in contact with the gas generating agent 60. The second pressing portion 72b is provided at the end of the spring portion 71 on the auto-ignition agent 61 side. The second pressing portion 72b is in contact with the auto-ignition agent 61.

[0085] The coil spring 70 is compressed by being interposed between the auto-ignition agent 61 and the gas generating agent 60. As a result, the gas generating agent 60 is elastically biased toward the igniter 40 side by the spring portion 71, while being separated from the auto-ignition agent 61 via the first pressing portion 72a. In this way, the gas generating agent 60 is fixed inside the gas generating agent containment chamber S1. This configuration prevents the molded gas generating agent 60 from being crushed by vibration or the like.

[0086] The auto-ignition agent 61 is elastically biased toward the partition wall 51 by the spring portion 71 via the second pressing portion 72b, while being separated from the gas generating agent 60. As a result, the auto-ignition agent 61 is fixed inside the gas generating agent containment chamber S1 so as to be in contact with the second main surface 51b of the partition wall 51.

[0087] When the coil spring 70 is assembled, it is compressed by being sandwiched between the auto-ignition agent 61 and the gas generating agent 60, which allows the coil spring 70 to absorb dimensional variations in the various components housed inside the housing.

[0088] When viewed along the axial direction of the peripheral wall portion 10, the spring portion 71 of the coil spring 70 includes a constricted portion 73 whose outer diameter is smaller than that of either the first pressing portion 72a or the second pressing portion 72b.

[0089] When a coil spring 70 including a constricted portion 73 is interposed between the auto-ignition agent 61 and the gas generating agent 60, the auto-ignition agent 61 and the gas generating agent 60 are subjected to both the repulsive force generated by the compression deformation of the coil spring 70 and the repulsive force generated by the torsional deformation of the coil spring 70. In other words, the coil spring 70 including a constricted portion 73 can be subjected to a greater compressive load by the auto-ignition agent 61 and the gas generating agent 60 compared to a coil spring with the same axial length but without a constricted portion (for example, a coil spring with a substantially cylindrical outer shape) by the amount of the repulsive force associated with torsional deformation.

[0090] Thus, by employing a coil spring 70 that can apply a larger compressive load, it becomes possible to fill the gas generating agent chamber S1 with the gas generating agent 60 at a higher density. As a result, the axial length of the cylinder-type gas generator 1A can be shortened, and consequently, the cylinder-type gas generator 1A can be made smaller and lighter.

[0091] The auto-ignition agent 61 consists of pellets formed into a flattened, roughly cylindrical shape. The auto-ignition agent 61 is positioned on the opposite side of the coil spring 70 from where the gas generating agent 60 is located (i.e., on the filter 80 side), and is held in place by being sandwiched between the partition wall 51 of the partition member 50 and the coil spring 70. In this way, the auto-ignition agent 61 is separated from the gas generating agent 60 by the coil spring 70.

[0092] The auto-ignition agent 61 is an agent that ignites automatically without the operation of the igniter 40. More specifically, the auto-ignition agent 61 spontaneously ignites at a lower temperature than the gas generating agent 60, and is intended to prevent the cylinder-type gas generator 1A from being heated from the outside and causing abnormal operation in the event of a fire or other incident in a vehicle equipped with an airbag system that incorporates a cylinder-type gas generator 1A.

[0093] As shown in Figures 1 and 3, the filter 80 is placed in the space within the housing that is sandwiched between the closing member 30 and the partition member 50 (i.e., the filter chamber S2).

[0094] The filter 80 consists of a cylindrical member having a cavity 81 extending in a direction substantially parallel to the axial direction of the peripheral wall portion 10. The filter 80 is positioned in the filter chamber S2 such that its axial direction is substantially parallel to the axial direction of the peripheral wall portion 10. One of the pair of axial end faces of the filter 80 is in pressure contact with the closing member 30, and the other of the pair of axial end faces of the filter 80 is in pressure contact with the first main surface 51a of the partition wall portion 51 of the partition member 50.

[0095] The filter 80 functions as a cooling means that cools the gas generated by the combustion of the gas generating agent 60 by removing the high-temperature heat from the gas as it passes through the filter 80, and also functions as a removal means that removes slag (residue) and other substances contained in the gas. As described above, by using a filter 80 made of a cylindrical member, the flow resistance to the gas flowing through the filter chamber S2 during operation is kept low, enabling efficient gas flow.

[0096] The filter 80 can preferably be made of an assembly of metal wires or metal mesh materials made of stainless steel or iron. Specifically, it can be made of knitted wire mesh, plain woven wire mesh, an assembly of crimped metal wires, or these materials compressed by pressing.

[0097] As the filter 80, a rolled-up perforated metal plate can also be used. In this case, as the perforated metal plate, for example, expanded metal can be used, which is made by cutting a metal plate in a staggered pattern and then expanding the cuts to form holes and create a mesh-like structure, or hook metal can be used, which is made by drilling holes in a metal plate and then flattening the burrs that form around the edges of the holes.

[0098] Multiple gas outlets 14 are provided along the circumferential and axial directions on the peripheral wall portion 10 of the part that defines the filter chamber S2. These multiple gas outlets 14 are for guiding the gas that has passed through the filter 80 to the outside of the housing.

[0099] Here, if the outer diameter of the filter 80 is F1 and the inner diameter of the peripheral wall portion 10 is H, then the cylinder-type gas generator 1A satisfies the following equation (1). F1 <H···(1)

[0100] Thereby, a gap portion 82 of a predetermined size is provided between the filter 80 and the peripheral wall portion 10 of the part that defines the filter chamber S2. By providing the gap portion 82, the gas generated by the combustion of the gas generating agent 60 passes through substantially the entire area in the filter 80, so that the utilization efficiency of the filter 80 can be improved.

[0101] Further, the cylinder-type gas generator 1A satisfies the following relational expression (2). Thereby, regardless of the position of the filter 80 in the radial direction of the peripheral wall portion 10, the axial end face of the filter 80 is in contact with the outer peripheral edge of the first main surface 51a of the partition wall portion 51. The details of the relational expression (2) will be described later. (H-F1)≦(H-R) / 2≦(F1-F2) / 2···(2)

[0102] <B. Operation of the cylinder-type gas generator> Next, with reference to FIG. 1, the operation of the cylinder-type gas generator 1A according to the present embodiment during actuation will be described.

[0103] With reference to FIG. 1, when a vehicle equipped with the cylinder-type gas generator 1A according to the present embodiment collides, the collision is detected by a collision detection unit separately provided in the vehicle, and based on this, the igniter 40 is actuated by energization from a control unit separately provided in the vehicle.

[0104] When the igniter 40 is actuated, the pressure inside the ignition portion 42 rises as the ignition charge or, in addition thereto, the transfer charge combusts, whereby the squib cup of the ignition portion 42 ruptures, and hot particles generated by the combustion of the ignition charge or, in addition thereto, the transfer charge flow out of the ignition portion 42. The hot particles that have reached the gas generating agent 60 cause the gas generating agent 60 to combust, whereby a large amount of gas is generated inside the gas generating agent storage chamber S1.

[0105] Along with this, the pressure in the gas generating agent storage chamber S1 rises, and when the internal pressure of the gas generating agent storage chamber S1 reaches a predetermined pressure, fracture occurs in the portion of the partition member 50 where the score 51a1 is provided. As a result, an opening is formed in the partition member 50 at the portion facing the hollow portion 81 of the filter 80, and the gas generating agent storage chamber S1 and the filter chamber S2 communicate with each other via the opening.

[0106] Along with this, the gas generated in the gas generating agent storage chamber S1 flows into the filter chamber S2 through the opening formed in the partition member 50. The gas that has flowed into the filter chamber S2 flows along the axial direction through the hollow portion 81 of the filter 80, then changes its direction toward the radial direction and flows through the inside of the filter 80. At that time, heat is taken away by the filter 80 to cool the gas, and slag contained in the gas is removed by the filter 80.

[0107] Then, the gas after flowing through the filter 80 is ejected to the outside of the housing through the gas ejection port 14 provided in the peripheral wall portion 10. The ejected gas is introduced into the interior of an airbag provided adjacent to the cylinder-type gas generator 1A, to inflate and deploy the airbag. The auto-ignition composition 61 burns together with the gas generating agent 60 when the gas generating agent 60 is combusted.

[0108] <C. Assembly Procedure for Cylinder-Type Gas Generator> FIG. 5 is a flowchart showing the assembly procedure of the cylinder-type gas generator shown in FIG. 1. FIG. 6 to FIG. 9 are schematic cross-sectional views for explaining each step shown in FIG. 5. Next, the assembly procedure of the cylinder-type gas generator 1A according to the present embodiment will be described with reference to FIG. 5 to FIG. 9.

[0109] When assembling the cylinder-type gas generator 1A, as shown in FIG. 5 and FIG. 6, first, in step ST1, the partition member 50 is inserted into the cylindrical peripheral wall portion 10 of the housing.

[0110] In detail, first, the partition member 50 is positioned such that its opening surface is on the opposite side from the peripheral wall portion 10, and the central axis of the annular wall portion 52 generally coincides with the central axis of the peripheral wall portion 10. Next, the partition member 50, positioned in this manner, is press-fitted into the interior of the peripheral wall portion 10 such that the first main surface 51a and the second main surface 51b of the partition wall portion 51 are substantially perpendicular to the axial direction of the peripheral wall portion 10.

[0111] Next, as shown in Figures 5 and 7, in step ST2, the partition member 50 is fixed to the peripheral wall portion 10 of the housing.

[0112] In detail, with the partition member 50 inserted into the peripheral wall portion 10, the laser LA is irradiated from the torch 100 of the laser welding machine toward a predetermined portion of the outer surface of the peripheral wall portion 10.

[0113] Simultaneously with this irradiation, the peripheral wall portion 10 rotates in the direction of arrow DR shown in Figure 7, with its central axis CL as the center of rotation. As a result, a weld portion 90, which welds the annular wall portion 52 and the peripheral wall portion 10, is formed extending along the circumferential direction of the peripheral wall portion 10. Alternatively, instead of the peripheral wall portion 10 rotating, the torch 100 may move along the circumferential direction of the peripheral wall portion 10 while irradiating it with the laser LA.

[0114] In this laser welding, the welding conditions are appropriately adjusted so that the welded portion 90 is formed in the portion of the annular wall portion 52 that includes the separated portion 52b. Examples of such irradiation conditions include welding current, welding voltage, energizing time, and irradiation position on the outer surface of the peripheral wall portion 10.

[0115] In this embodiment, the welded portion 90 is provided on a part of the separated portion 52b of the annular wall portion 52 and on the peripheral wall portion 10 opposite to the part of the separated portion 52b. As a result, at least a part of the welded portion 90 faces the gap G.

[0116] Next, as shown in Figures 5 and 8, in step ST3, the cylindrical filter 80 is inserted into the peripheral wall portion 10.

[0117] In detail, the filter 80 is inserted into the peripheral wall portion 10 such that its axial direction is approximately parallel to the axial direction of the peripheral wall portion 10, and the filter 80 is located on the opposite side from the side where the annular wall portion 52 is located when viewed from the partition wall portion 51.

[0118] In step ST3, the peripheral wall portion 10, the filter 80, and the partition member 50 are configured to satisfy a predetermined relational expression, thereby suppressing dimensional variations after assembly and enabling the manufacture of a gas generator with stable quality. This point will be described in detail later.

[0119] Next, as shown in Figures 5 and 8, in step ST4, the closing member 30 is inserted into the peripheral wall portion 10.

[0120] In detail, the closure member 30 is inserted into the peripheral wall portion 10 such that the filter 80 is sandwiched between the partition member 50 and the closure member 30 in the axial direction of the peripheral wall portion 10.

[0121] Next, as shown in Figures 5 and 9, in step ST5, the blocking member 30 and the filter 80 are fixed to the peripheral wall portion 10 of the housing.

[0122] In detail, with the partition member 50 fixed to the peripheral wall portion 10 and the closing member 30 inserted into the peripheral wall portion 10, a crimping is performed to reduce the diameter of a predetermined position of the peripheral wall portion 10 radially inward (see arrow AR1 in Figure 9). This forms a crimped portion on the peripheral wall portion 10. The crimped portion formed here corresponds to the third crimped portion 13 described above.

[0123] The third crimping portion 13, the closing member 30, the filter 80, and the partition member 50 are positioned in this order from the other end 10b to the one end 10a in the axial direction of the peripheral wall portion 10 (see Figure 1).

[0124] The formation of the third crimping portion 13 on the peripheral wall portion 10 causes the closing member 30 to be pressed toward the filter 80 along the axial direction of the peripheral wall portion 10 (see arrow AR2 in Figure 9). The pressed closing member 30 contacts the axial end face of the filter 80 on the closing member 30 side and presses it toward the partition member 50 (see arrow AR3 in Figure 9). The axial end face of the pressed filter 80 opposite to the closing member 30 side contacts the first main surface 51a of the partition wall portion 51 of the partition member 50 and presses it toward the opposite side from the closing member 30 side when viewed from the filter 80 (see arrow AR4 in Figure 9).

[0125] As a result, the axial end face of the filter 80 on the side facing the closing member 30 is in pressure contact with the closing member 30, the axial end face of the filter 80 on the side facing the partition member 50 is in pressure contact with the first main surface 51a of the partition wall portion 51, and the closing member 30 and the filter 80 are fixed to the peripheral wall portion 10 with the third crimping portion 13 in pressure contact with the closing member 30.

[0126] After going through steps ST1 to ST5 described above, the auto-ignition agent 61, coil spring 70, and gas generating agent 60 are sequentially placed in the space within the peripheral wall portion 10 that is not occupied by the filter 80, etc., of the two spaces separated by the partition member 50. Next, the holder assembly 20 to which the igniter 40 is assembled is inserted into the peripheral wall portion 10. Then, the holder assembly 20 is fixed to the peripheral wall portion 10 by forming a first crimping portion 11 and a second crimping portion 12 on the peripheral wall portion 10.

[0127] By following the steps described above, the assembly of the cylinder-type gas generator 1A is completed.

[0128] The assembly procedure for the cylinder-type gas generator 1A described above is merely an example, and the order of each step can be changed as appropriate.

[0129] Furthermore, although the manufacturing method of the cylinder-type gas generator 1A described above exemplifies the case in which the welded portion 90 is provided by laser welding, the welded portion 90 may also be provided by other welding methods, such as electron beam welding or resistance welding.

[0130] In step ST5 described above, deformation occurs in the partition wall portion 51 of the partition member 50 due to pressure from the axial end face of the filter 80. The amount of deformation of the partition wall portion 51 differs depending on which part of the partition wall portion 51 the axial end face of the filter 80 is in contact with.

[0131] In other words, the amount of deformation when the axial end face of the filter 80 abuts against the periphery of the partition wall 51 is smaller than the amount of deformation when the axial end face of the filter 80 abuts against the rest of the partition wall 51. This is because, as mentioned above, the rigidity of the periphery of the partition wall 51 is higher than the rigidity of the rest of the partition wall 51.

[0132] As described above, the filter 80 and the peripheral wall portion 10 satisfy equation (1) above (i.e., the outer diameter F1 of the filter 80 is smaller than the inner diameter H of the peripheral wall portion 10). Therefore, it is difficult to position the filter 80 in the desired position in the radial direction of the peripheral wall portion 10, and if no measures are taken, the position of the partition wall portion 51 in the part that the axial end face of the filter 80 abuts will vary from product to product.

[0133] This results in variations in the deformation of the partition wall 51 from product to product, and consequently, variations in the distance between the closing member 30 and the third crimping portion 13 from product to product. As a result, variations in pressure resistance performance occur from product to product, making it difficult to stabilize the quality of the manufactured gas generators.

[0134] In this regard, in the cylinder-type gas generator 1A according to this embodiment, the peripheral wall portion 10, the filter 80, and the partition member 50 are configured to satisfy a predetermined relational expression in step ST3 (see Figure 5), thereby preventing variations in the position of the partition wall portion 51 in the portion that the axial end face of the filter 80 abuts.

[0135] This point will be explained below with reference to Figures 10 and 11. Figure 10 shows one configuration of the filter's position in the radial direction of the peripheral wall portion, as assumed in process ST3. Figure 11 shows another configuration of the filter's position in the radial direction of the peripheral wall portion, as assumed in process ST3. In both configurations, the partition member 50 is arranged coaxially with the peripheral wall portion 10.

[0136] In the embodiment shown in Figure 10, the filter 80 is arranged coaxially with the peripheral wall portion 10. In this case, the following relationship must be satisfied for the axial end face of the filter 80 to abut against the outer peripheral edge of the first main surface 51a of the partition wall portion 51. Hereinafter, H is the inner diameter of the peripheral wall portion 10, F1 is the outer diameter of the filter 80, F2 is the inner diameter of the filter 80, and R is the diameter of the outer peripheral edge of the first main surface 51a of the partition wall portion 51 of the partition member 50. (H-F1) / 2≦(HR) / 2≦(H-F1) / 2+(F1-F2) / 2

[0137] Rearranging the above relationship, we obtain the following relationship (X). (H-F1) / 2≦(HR) / 2≦(H-F2) / 2···(X)

[0138] On the other hand, in the embodiment shown in Figure 11, a portion of the outer circumferential surface of the filter 80 abuts against the inner circumferential surface of the peripheral wall portion 10, and the filter 80 is eccentrically positioned with respect to the central axis of the peripheral wall portion 10. In this case, in order for the axial end face of the filter 80 to abut against the outer circumferential edge of the first main surface 51a of the partition wall portion 51, two relational equations must be satisfied.

[0139] The first relational expression is a relational expression for causing the axial end face of the filter 80 at the portion that abuts the inner circumferential surface of the peripheral wall portion 10 (that is, the axial end face of the portion whose cross section is located on the right side in FIG. 11) to abut the outer peripheral edge of the first main surface 51a of the partition wall portion 51. The relational expression is shown below. (H-R) / 2≦(F1-F2) / 2···(Y1)

[0140] The second relational expression is a relational expression for causing the axial end face of the filter 80 at the portion farthest from the inner circumferential surface of the peripheral wall portion 10 (that is, the axial end face of the portion whose cross section is located on the left side in FIG. 11) to abut the outer peripheral edge of the first main surface 51a of the partition wall portion 51. The relational expression is shown below. (H-F1)≦(H-R) / 2≦(H-F1)+(F1-F2) / 2···(Y2)

[0141] From the above relational expressions (Y1) and (Y2), in order for the axial end face of the filter 80 to abut the outer peripheral edge of the first main surface 51a of the partition wall portion 51 in the embodiment shown in FIG. 11, the following relational expression (Y) needs to be satisfied. (H-F1)≦(H-R) / 2≦(F1-F2) / 2···(Y)

[0142] From the above relational expressions (X) and (Y), in order for the axial end face of the filter 80 to abut the outer peripheral edge of the first main surface 51a of the partition wall portion 51 in both the embodiment shown in FIG. 10 and the embodiment shown in FIG. 11, the following relational expression (2) needs to be satisfied. (H-F1)≦(H-R) / 2≦(F1-F2) / 2···(2)

[0143] Note that as long as the relational expression (2) is satisfied, even when the outer circumferential surface of the filter 80 does not abut the inner circumferential surface of the peripheral wall portion 10 and the filter 80 is arranged eccentrically with respect to the central axis of the peripheral wall portion 10, the axial end face of the filter 80 abuts the outer peripheral edge of the first main surface 51a of the partition wall portion 51.

[0144] <D. Small Paragraph> As described above, in the cylinder-type gas generator 1A according to this embodiment, the utilization efficiency of the filter 80 can be increased by satisfying equation (1) above. Furthermore, by satisfying equation (2) above, regardless of the position of the filter 80 in the radial direction of the peripheral wall portion 10 in process ST3, the axial end face of the filter 80 can always be brought into contact with the outer peripheral edge of the first main surface 51a of the partition wall portion 51.

[0145] As a result, the rigidity of the partition wall portion 51 in the area where the axial end face of the filter 80 abuts during process ST3 remains constant. Therefore, the amount of deformation of the partition wall portion 51 due to being pressed by the axial end face of the filter 80 during process ST5 remains constant, making it possible to effectively suppress variations in pressure resistance performance from product to product.

[0146] Therefore, by using the manufacturing method for the cylinder-type gas generator 1A according to this embodiment, it becomes possible to manufacture a gas generator with stable quality by suppressing dimensional variations after assembly.

[0147] (Other forms, etc.) In the above-described embodiment, an example was given in which a holder assembly consisting of a first metal holder that primarily functions to hold the igniter, a second resin holder that primarily functions as a direction-imparting member, and a third resin holder that primarily constitutes a female connector portion is used. However, instead of such a holder assembly, a holder made of a single component may be used. Furthermore, this holder does not necessarily have to function as a direction-imparting member.

[0148] Furthermore, the shape, size, number, and placement of each component disclosed in the above-described embodiments can, of course, be modified in various ways without departing from the spirit of the present invention.

[0149] Furthermore, although the above-described embodiment illustrates the application of the present invention to a cylindrical gas generator incorporated into a side airbag system, the application of the present invention is not limited to this. It can also be applied to cylindrical gas generators incorporated into curtain airbag systems, knee airbag systems, seat cushion airbag systems, etc., as well as so-called T-shaped gas generators that have a long external shape similar to that of a cylindrical gas generator.

[0150] Thus, the forms of implementation disclosed herein are illustrative in all respects and not restrictive. The technical scope of the present invention is defined by the claims and includes all modifications within the meaning and scope of equivalents to the claims. [Explanation of Symbols]

[0151] 1A Cylinder-type gas generator, 10 Peripheral wall section, 10a One end, 10b Other end, 10c Straight section, 11 First crimped section, 12 Second crimped section, 13 Third crimped section, 14 Gas outlet, 20 Holder assembly, 20A First holder, 20B Second holder, 20C Third holder, 21 First body section, 21a First housing section, 21b Crimped section, 22 Annular projection, 23 Second body section, 23a Second housing section, 24 Projection, 26 Cover section, 26a Opening, 27 Third body section, 27a Third housing section, 28 Seal member, 30 Closure member, 40 Ignition device, 41 Base section, 42 Ignition section, 43 Terminal pin, 50 Partition member, 51 Partition wall section, 51a First main surface, 51a1 Score, 51b Second main surface, 52 Annular wall section, 52a Contact section, 52b Separation section, 60 Gas generating agent, 61 Auto-ignition agent, 70 Coil spring, 71 Spring section, 72a First pressing section, 72b Second pressing section, 73 Constriction section, 80 Filter, 81 Cavity section, 82 Gap section, 90 Welded section, 100 Torch, CL Central axis, G Gap, J Connecting surface, LA Laser, S1 Gas generating agent containment chamber, S2 Filter chamber.

Claims

1. A partition member having a disc-shaped partition wall portion including a pair of main surfaces and an annular wall portion erected from the periphery of the partition wall portion, is inserted into the circumferential wall portion such that the pair of main surfaces are substantially perpendicular to the axial direction of the cylindrical circumferential wall portion of the housing. The process of fixing the partition member to the housing by welding the annular wall portion to the peripheral wall portion while the partition member is inserted into the peripheral wall portion, A step of inserting a cylindrical filter into the peripheral wall portion such that the axial direction of the filter is substantially parallel to the axial direction of the peripheral wall portion and is located on the opposite side from the side where the annular wall portion is located when viewed from the partition wall portion, A step of inserting the closing member into the peripheral wall portion such that the filter is sandwiched between the partition member and the closing member in the axial direction of the peripheral wall portion, With the partition member fixed to the housing and the closing member inserted into the peripheral wall, the peripheral wall is crimped such that a crimped portion is formed on the peripheral wall that is reduced in diameter radially inward, so that the axial end face of the filter on the closing member side is in pressure contact with the closing member, the axial end face of the filter on the partition member side is in pressure contact with the main surface of the partition wall located on the filter side of the pair of main surfaces, and the closing member and the filter are fixed to the housing in a state where the crimped portion is in pressure contact with the closing member. A method for manufacturing a gas generator, wherein, in the step of inserting the filter into the peripheral wall, the inner diameter of the peripheral wall is H, the outer diameter of the filter is F1, the inner diameter of the filter is F2, and the diameter of the outer peripheral edge of the main surface of the partition wall that is located on the filter side is R, the following equations (1) and (2) are satisfied. F1<H...(1) (H-F1)≦(HR) / 2≦(F1-F2) / 2...(2)

2. The method for manufacturing a gas generator according to claim 1, wherein the connecting surface that connects the main surface of the partition wall portion located on the filter side and the outer peripheral surface of the annular wall portion is a curved surface with a radius of curvature of 1 mm or more.

3. A housing having a cylindrical peripheral wall portion with one end and the other end closed in the axial direction, and containing a gas generating agent containment chamber in which a gas generating agent is contained and a filter chamber in which a cylindrical filter is arranged, A partition member is inserted into the peripheral wall portion to divide the space inside the housing in the axial direction of the peripheral wall portion, such that the gas generating agent containment chamber is located on one end side and the filter chamber is located on the other end side. An igniter attached to one end, The system includes a closing member that is inserted into the peripheral wall portion to close the other end, The filter is arranged in the filter chamber such that the axial direction of the filter is substantially parallel to the axial direction of the peripheral wall portion. The partition member has a disc-shaped partition wall portion including a pair of main surfaces substantially perpendicular to the axial direction of the peripheral wall portion, and an annular wall portion erected from the periphery of the partition wall portion toward the one end side and extending along the inner circumferential surface of the peripheral wall portion. The partition member is fixed to the housing by welding the annular wall portion and the peripheral wall portion together. The aforementioned peripheral wall portion has a crimped portion that is reduced in diameter toward the radially inward direction. The crimping portion, the closing member, the filter, and the partition member are positioned in this order from the other end to the one end in the axial direction of the peripheral wall portion. The axial end face of the filter on the side of the blocking member is in pressure contact with the blocking member. The axial end face of the filter on the partition member side is in pressure contact with the main face located on the other end side of the pair of main faces of the partition wall portion. The crimped portion is in pressure contact with the closing member, A gas generator that satisfies the following equations (1) and (2), where H is the inner diameter of the peripheral wall, F1 is the outer diameter of the filter, F2 is the inner diameter of the filter, and R is the diameter of the outer edge of the main surface located on the other end side of the pair of main surfaces of the partition wall. F1<H...(1) (H-F1)≦(HR) / 2≦(F1-F2) / 2...(2)

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