Gas generator and manufacturing method thereof

Abstract

To provide a gas generator in which sealing performance in a welding section for welding a partition member and a housing is improved.SOLUTION: A gas generator 1A includes: a housing having a peripheral wall section 10; a partition member 50; and an igniter. The partition member 50 partitions a space in the housing in an axial direction of the peripheral wall section 10 by being inserted into the peripheral wall section 10 and has an annular wall section 51 extending along an inner peripheral surface of the peripheral wall section 10 and a partition wall section 52 closing one end in an axial direction of the annular wall section 51. The annular wall section 51 has an abutting section 51a abutting on the inner peripheral surface of the peripheral wall section 10 and a separation section 51b that is spaced apart from the inner peripheral surface of the peripheral wall section 10 to form a gap G between the inner peripheral surface of the peripheral wall section 10 and the separation section. A welding section 90 for welding the annular wall section 51 and the peripheral wall section 10 is provided in a portion including the separation section 51b of the annular wall section 51, so that at least a part of the welding section 90 faces the gap G.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a gas generator to be incorporated into an airbag device as an occupant protection device equipped in an automobile or the like, and a manufacturing method thereof, and more particularly to a so-called cylinder-type gas generator having an elongated cylindrical outer shape that is suitably incorporated into a side airbag device or the like, and a manufacturing method thereof. [Background technology]

[0002] Airbag devices, which are passenger protection devices, have become widespread from the viewpoint of protecting passengers in automobiles, etc. Airbag devices are installed to protect passengers from impacts that occur during a vehicle collision, and the airbag instantly inflates and deploys during a vehicle collision, thereby acting as a cushion to support the passenger's body.

[0003] The gas generator is incorporated into this airbag device. When a vehicle crashes, the control unit energizes the igniter, which then generates a flame that burns the gas generating agent, instantly generating a large amount of gas, which inflates and deploys the airbag.

[0004] There are gas generators of various configurations based on specifications such as the installation position relative to a vehicle, output, etc. One of these is what is called a cylinder-type gas generator. A cylinder-type gas generator has an elongated cylindrical outer shape and is suitably incorporated into a side airbag device, a curtain airbag device, a knee airbag device, a seat cushion airbag device, etc.

[0005] Typically, in a cylinder-type gas generator, an igniter is assembled to one axial end of the housing, and a gas generating agent storage chamber containing gas generating agent is provided on the one end side, a filter chamber containing a filter is provided on the other axial end side of the housing, and a gas outlet is provided on the peripheral wall of the housing in a portion that defines the filter chamber.

[0006] In a cylinder-shaped gas generator configured in this manner, gas generated in the gas generating agent storage chamber flows into the filter chamber along the axial direction of the housing, passing through the inside of the filter, and the gas after passing through the filter is ejected to the outside through the gas ejection port.

[0007] In a cylinder-type gas generator, a partition member is sometimes installed in the interior space of the housing to divide the interior space of the housing in the axial direction into a gas generating agent storage chamber and a filter chamber.

[0008] The partition member has, for example, an annular wall portion extending along the inner circumferential surface of the housing and a partition wall portion closing one axial end of the annular wall portion. The partition member configured in this manner is fixed to the housing by welding the annular wall portion to the housing.

[0009] An example of a document disclosing a cylinder-type gas generator equipped with such a partition member is Japanese Patent Application Laid-Open No. 2022-144932 (Patent Document 1). [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2022-144932 Summary of the Invention [Problem to be solved by the invention]

[0011] In a cylindrical gas generator having a partition member, when the annular wall portion of the partition member is welded to the housing, gas may be trapped at the interface between the housing and the weld and / or the interface between the annular wall portion and the weld, causing blowholes to form at the interface. When blowholes form in this way, it becomes difficult to ensure sealing at the weld.

[0012] Therefore, the present invention has been made in consideration of the above-mentioned problems, and has an object to provide a gas generator and a manufacturing method thereof in which the sealing performance at the welded joint between the partition member and the housing is improved. [Means for solving the problem]

[0013] A gas generator according to the present invention includes a housing, a partition member, and an igniter. The housing has a cylindrical peripheral wall portion whose one and other axial ends are closed, and contains therein a gas generating agent storage chamber containing a gas generating agent and a filter chamber in which a filter is disposed. The partition member is inserted into the peripheral wall portion so that the gas generating agent storage chamber is located at the one end and the filter chamber is located at the other end, thereby dividing the interior space of the housing in the axial direction of the peripheral wall portion. The igniter is assembled to the one end of the peripheral wall portion. The partition member has an annular wall portion and a partition portion. The annular wall portion extends along the inner circumferential surface of the peripheral wall portion. The partition portion closes one axial end of the annular wall portion. The partition member is fixed to the housing by welding the annular wall portion and the peripheral wall portion together. The annular wall portion includes an abutting portion in contact with the inner circumferential surface of the peripheral wall portion, and a separating portion located spaced apart from the inner circumferential surface of the peripheral wall portion to provide a gap between the inner circumferential surface of the peripheral wall portion. In the gas generator based on the present invention, a weld portion that welds the annular wall portion and the peripheral wall portion is provided in a portion of the annular wall portion that includes the separating portion, so that at least a part of the weld portion faces the gap.

[0014] In the gas generator based on the present invention, the abutting portion and the separating portion may be positioned adjacent to each other in the axial direction.

[0015] In the gas generator according to the present invention, the separating portion may include an inclined portion inclined so as to move away from the inner circumferential surface of the peripheral wall portion from the one end side toward the other end side, and a portion continuing from an end portion of the inclined portion located on the other end side and extending along a direction approximately parallel to the inner circumferential surface of the peripheral wall portion. In this case, the abutting portion may be provided continuing from the end portion located on the one end side of the inclined portion.

[0016] In the gas generator based on the present invention, the abutting portion may include a first abutting portion and a second abutting portion located closer to the other end in the axial direction than the first abutting portion. In that case, the separating portion may be located so as to be sandwiched between the first abutting portion and the second abutting portion in the axial direction.

[0017] In the gas generator based on the present invention, the abutting portion and the separating portion may be positioned adjacent to each other in the circumferential direction of the peripheral wall portion.

[0018] In the gas generator according to the present invention, the gap may communicate with the gas generating agent storage chamber or the filter chamber.

[0019] A method for manufacturing a gas generator according to the present invention includes the steps of inserting a partition member having an annular wall portion and a partition portion closing one axial end of the annular wall portion into a cylindrical peripheral wall portion of a housing, and welding the annular wall portion to the peripheral wall portion with the partition member inserted into the peripheral wall portion to fix the partition member to the housing. With the partition member inserted into the peripheral wall portion, the annular wall portion includes an abutting portion that abuts against an inner circumferential surface of the peripheral wall portion, and a separating portion that is positioned spaced apart from the inner circumferential surface of the peripheral wall portion to provide a gap between the inner circumferential surface of the peripheral wall portion. In the method for manufacturing a gas generator according to the present invention, in the step of welding the annular wall portion to the peripheral wall portion, the weld portion welding the annular wall portion to the peripheral wall portion is provided in a portion of the annular wall portion that includes the separating portion, such that at least a part of the weld portion welding the annular wall portion to the peripheral wall portion faces the gap. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a gas generator in which the sealing performance at the welded portion where the partition member and the housing are welded is improved, and a method for manufacturing the same. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic view of a cylinder-shaped gas generator according to an embodiment. [Figure 2] 2 is an enlarged cross-sectional view of the vicinity of an igniter of the cylinder-shaped gas generator shown in FIG. 1. FIG. [Figure 3] 2 is an enlarged cross-sectional view of the vicinity of a closing member of the cylinder-shaped gas generator shown in FIG. 1. FIG. [Figure 4] 2 is an enlarged cross-sectional view of the vicinity of a partition member of the cylinder-shaped gas generator shown in FIG. 1. FIG. [Figure 5] FIG. 4 is a schematic diagram of the partition member before being inserted into the peripheral wall portion. [Figure 6] 1. FIG. 4 is a flowchart showing a procedure for assembling a partition member to a peripheral wall portion of the cylinder-shaped gas generator shown in FIG. [Figure 7]It is a schematic cross-sectional view for explaining the procedure for assembling a partition member to the peripheral wall portion in the cylinder-type gas generator shown in FIG. 1. [Figure 8] It is a schematic cross-sectional view for explaining the procedure for assembling a partition member to the peripheral wall portion in the cylinder-type gas generator shown in FIG. 1. [Figure 9] It is a schematic cross-sectional view for explaining the first verification test. [Figure 10] It is a table showing the results of the first verification test. [Figure 11] It is a table showing the results of the second verification test. [Figure 12] It is an enlarged cross-sectional view of the vicinity of the partition member of the cylinder-type gas generator according to the first modification. [Figure 13] It is an enlarged cross-sectional view of the vicinity of the partition member of the cylinder-type gas generator according to the second modification. [Figure 14] It is an enlarged cross-sectional view of the vicinity of the partition member of the cylinder-type gas generator according to the third modification. [Figure 15] It is an enlarged cross-sectional view of the vicinity of the partition member of the cylinder-type gas generator according to the fourth modification. [Figure 16] It is an enlarged cross-sectional view of the vicinity of the partition member of the cylinder-type gas generator according to the fifth modification. [Figure 17] It is an enlarged cross-sectional view of the vicinity of the partition member of the cylinder-type gas generator according to the sixth modification.

Mode for Carrying Out the Invention

[0022] 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 the embodiments shown below, the same or common parts are denoted by the same reference numerals in the drawings, and the description thereof will not be repeated.

[0023] (Embodiment) <A. Configuration of Cylinder-Type Gas Generator> FIG. 1 is a schematic diagram of a cylinder-shaped gas generator according to an embodiment. FIG. 2 is an enlarged cross-sectional view of the vicinity of an igniter of the cylinder-shaped gas generator shown in FIG. 1. FIG. 3 is an enlarged cross-sectional view of the vicinity of a closing member of the cylinder-shaped gas generator shown in FIG. 1. FIG. 4 is an enlarged cross-sectional view of the vicinity of a partition member of the cylinder-shaped gas generator shown in FIG. 1. FIG. 5 is a schematic view of the partition member in a state prior to insertion into the peripheral wall portion. In detail, FIG. 5(A) is a schematic view of the partition member as seen from the annular wall portion side in the axial direction. FIG. 5(B) is a schematic cross-sectional view taken along line VB-VB shown in FIG. 5(A). First, the configuration of a cylinder-shaped gas generator 1A according to the present embodiment will be described with reference to FIGS. 1 to 5.

[0024] 1 to 5, cylinder-shaped gas generator 1A has a long, columnar outer shape, and has a long, substantially cylindrical housing with one axial end and the other end closed. The housing includes a peripheral wall portion 10, a holder assembly 20, a closing member 30, and a partition member 50, of which peripheral wall portion 10, holder assembly 20, and closing member 30 define the outer shell of the housing.

[0025] The igniter 40, gas generating agent 60, auto-ignition agent 61, coil spring 70, filter 80, and other internal components are accommodated inside the peripheral wall 10, holder assembly 20, and closing member 30 that define the outer shell of the housing, and in addition to these, the above-mentioned partition member 50, which is also an internal component, is disposed. Also located inside the housing are a gas generating agent accommodation chamber S1 that accommodates the gas generating agent 60, auto-ignition agent 61, and coil spring 70, which are among the above-mentioned internal components, and a filter chamber S2 that accommodates the filter 80.

[0026] The peripheral wall 10 is a long cylindrical member with openings formed at both axial ends. One axial end of the peripheral wall 10 is closed by a holder assembly 20, and the other axial end of the peripheral wall 10 is closed by a closing member 30.

[0027] The peripheral wall 10 may be made of a metal member such as stainless steel, iron steel, aluminum alloy, or stainless alloy, or may be made of a press-formed product formed into a cylindrical shape by pressing a rolled steel plate such as SPCE.The peripheral wall 10 may also be made of an electric resistance welded pipe such as STKM.

[0028] In particular, when the peripheral wall portion 10 is constructed from a press-formed product of rolled steel plate or an electric resistance welded pipe, the peripheral wall portion 10 can be formed more cheaply and easily than when using metal components such as stainless steel or steel, and the weight can be significantly reduced.

[0029] The holder assembly 20 is fixed to the peripheral wall portion 10 so as to close one open end of the peripheral wall portion 10 in the axial direction.

[0030] In detail, with the holder assembly 20 inserted into the one open end 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, thereby crimping and fixing the holder assembly 20 to the peripheral wall portion 10. The holder assembly 20 may be fixed to the peripheral wall portion 10 by, for example, welding at or near the contact portion with the peripheral wall portion 10.

[0031] 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 is made of a substantially cylindrical member having a hollow portion extending in a direction parallel to the axial direction of the peripheral wall portion 10.

[0032] The first holder 20A is configured as a flat, substantially disk-shaped member having a through-hole extending axially in its center, and includes a cylindrical first barrel 21 and an annular protrusion 22 protruding outward from the outer peripheral surface of the first barrel 21. The annular protrusion 22 is provided at the end of the first barrel 21 on the gas generating agent storage chamber S1 side.

[0033] The first holder 20A has a concave first housing portion 21a at its axial end on the gas generating agent housing chamber S1 side to receive the igniter 40. This first housing portion 21a communicates with a through-hole provided in the first holder 20A and defines part of the hollow portion described above of the holder assembly 20. Furthermore, a crimping portion 21b is provided at the end of the first holder 20A on the gas generating agent housing chamber S1 side so as to surround the first housing portion 21a. The crimping portion 21b is a portion for crimping and fixing the igniter 40 to the first holder 20A.

[0034] A seal member 28 made of an O-ring or the like is interposed between first holder 20A and igniter 40. As a result, the gap between first holder 20A and igniter 40 is filled with seal member 28, thereby sealing the gap.

[0035] The second holder 20B is configured as a substantially cylindrical member having a second storage portion 23a in the shape of a generally through hole extending axially in its center, and includes a cylindrical second body portion 23 and a lid portion 26 provided so as to cover one axial end of the second storage portion 23a. The second holder 20B is disposed on the gas generating agent storage chamber S1 side as viewed from the first holder 20A, and is positioned adjacent to the first holder 20A.

[0036] Second housing portion 23a houses ignition portion 42 of igniter 40. That is, second holder 20B is positioned so as to surround the periphery of ignition portion 42 of igniter 40 held by first holder 20A, and thereby the portion of second body portion 23 of second holder 20B that is closer to first holder 20A is positioned so as to surround the circumferential surface of ignition portion 42. Ignition portion 42 will be described in detail later.

[0037] The lid portion 26 is provided at the axial end of the second body portion 23 on the opposite side to the first holder 20A side so as to be located a predetermined distance away from the ignition portion 42. A plurality of openings 26a are provided in the lid portion 26, and the maximum outer dimension of each of these plurality of openings 26a when viewed along the axial direction of the peripheral wall portion 10 is configured to be smaller than the minimum outer dimension of the gas generating agent 60.

[0038] As a result, the second housing portion 23a, which is located on the opposite side of the igniter 40 from the base portion 41 side as viewed from the ignition portion 42, is substantially closed by the lid portion 26 at a position a predetermined distance away from the ignition portion 42, preventing the gas generating agent 60 from entering the second housing portion 23a and separating the gas generating agent 60 so that it is positioned at a distance from the ignition portion 42. The base portion 41 will be described in detail later.

[0039] In this way, second holder 20B functions as a directionality imparting member that imparts directionality to the direction of travel of thermal particles generated in ignition portion 42 when cylinder-shaped gas generator 1A is activated, by filling the gap between ignition portion 42 and peripheral wall portion 10, and in particular, second body portion 23 of second holder 20B has this function.

[0040] The third holder 20C is configured as a substantially cylindrical member having a third accommodating portion 27a in the form of a through hole extending along the axial direction in its central portion, and includes a cylindrical third trunk portion 27. The third holder 20C is disposed on the opposite side of the gas generating agent accommodating chamber S1 as viewed from the first holder 20A, and is positioned adjacent to the first holder 20A.

[0041] The third housing portion 27a houses a pair of terminal pins 43 of the igniter 40. The third housing portion 27a forms a portion for receiving a connector for connecting a harness. The terminal pins 43 will be described in detail later.

[0042] Here, a plurality of protrusions 24 are provided on the inner circumferential surface of a portion of second body portion 23 of second holder 20B that is compressed radially inward by pressure contact with first crimping portion 11 and that faces the outer circumferential surface of ignition portion 42. When viewed along the axial direction of second holder 20B, these multiple protrusions 24 are positioned in a dotted row along the circumferential direction of second body portion 23 and protrude toward ignition portion 42. First crimping portion 11 will be described in detail later.

[0043] The inner diameter of second holder 20B (i.e., the diameter of second housing portion 23a) is configured to be slightly larger than the diameter of ignition portion 42. The protrusion amounts of multiple protrusions 24 are adjusted so that, when ignition portion 42 is inserted into second body portion 23 of second holder 20B, their tips come into pressure contact with the outer peripheral surface of ignition portion 42 with a relatively weak force.

[0044] Therefore, when and after the ignition portion 42 is pressed into the second body portion 23, only the multiple protrusions 24 abut against the outer peripheral surface of the ignition portion 42, and in areas other than those where these multiple protrusions 24 are provided, a gap is formed between the outer peripheral surface of the ignition portion 42 and the inner peripheral surface of the second body portion 23.

[0045] As a result, during and after press-fitting of ignition part 42 into second body part 23, the majority of the area where ignition part 42 and second body part 23 face each other is separated by the gap, and only the tips of multiple protrusions 24 come into pressure contact with ignition part 42. Therefore, even while press-fitting ignition part 42 into second body part 23, it is possible to minimize deformation of ignition part 42 due to this.

[0046] The first holder 20A is made of a metal member such as stainless steel, iron steel, aluminum alloy, or stainless alloy.

[0047] The material of second holder 20B and 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. Second holder 20B and third holder 20C may be made of the same type of material or different types of materials.

[0048] 1 and 3, the blocking member 30 is a substantially disk-shaped member. The blocking 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 blocking member 30 is inserted into the open end of the peripheral wall portion 10 located opposite the side to which the holder assembly 20 is fixed (i.e., the left open end in FIG. 1) so that one axial end face of the blocking member 30 is abutted against the filter 80, and a predetermined position of the peripheral wall portion 10 is reduced in diameter radially inward toward the vicinity of the other axial end face of the blocking member 30, thereby crimping and fixing the blocking member 30 to the peripheral wall portion 10.

[0049] These crimping fixations are called eight-way crimping, which reduces the diameter of the peripheral wall portion 10 approximately uniformly inward in the radial direction. By performing this 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, and a third crimping portion 13 for fixing the blocking member 30. This brings the peripheral wall portion 10 into direct contact with the holder assembly 20 and the blocking member 30, respectively, preventing gaps from occurring between them.

[0050] In this embodiment, the crimping length L1 (see FIG. 3 ) is a distance in the axial direction of the peripheral wall 10 between one of the pair of axial end faces of the peripheral wall 10 on which the blocking member 30 is located and the other of the pair of axial end faces of the blocking member 30 on which the end face of the peripheral wall 10 is located, and is configured to be considerably long. Accordingly, the peripheral wall 10 has a straight portion 10b that extends a considerable length along the axial direction in a portion that is located closer to the end face of the peripheral wall 10 than the third crimping portion 13.

[0051] This configuration improves the fixing strength of the blocking member 30 to the peripheral wall portion 10 by the third crimping portion 13. The effect of improving the fixing strength by configuring the crimping length L1 to be considerably long has been confirmed by the second verification test described later.

[0052] Furthermore, with this configuration, handling during manufacturing of cylinder-shaped gas generator 1A becomes easier, and manufacturing efficiency of cylinder-shaped gas generator 1A can be improved.

[0053] That is, unless the crimping length L1 is configured to be sufficiently long, the provision of the third crimping portion on the peripheral wall portion causes the peripheral wall portion located closer to the end face of the peripheral wall portion than the third crimping portion to have an expanded diameter such that the outer diameter dimension increases with increasing distance from the third crimping portion, resulting in the outer diameter at the end face of the peripheral wall portion being larger than the outer diameter of the remaining portion of the peripheral wall portion.

[0054] In this regard, in cylinder-shaped gas generator 1A according to the present embodiment, crimping length L1 is configured to be considerably long, thereby preventing the outer diameter at the end face of peripheral wall portion 10 from becoming larger than the outer diameter of the remaining portion of peripheral wall portion 10.

[0055] As a result, the outer diameter of peripheral wall portion 10 in cylinder-shaped gas generator 1A is configured to be uniform over most of the axial direction, and the maximum outer dimension when viewed along the axial direction of peripheral wall portion 10 is configured to be smaller than when crimping length La is not configured to be significantly long. Therefore, handling during manufacture is easier, and cylinder-shaped gas generator 1A can be obtained with improved manufacturing efficiency.

[0056] The assembly structure of the closing member 30 to the peripheral wall portion 10 is not limited to the assembly structure described above, and other assembly structures may be adopted. Furthermore, the peripheral wall portion 10 and the closing member 30 may not be separate bodies, but may be configured as a single member having a cylindrical shape with a bottom.

[0057] The blocking member 30 is made of a metal member such as stainless steel, iron steel, aluminum alloy, or stainless alloy.

[0058] 1 and 2, igniter 40 is mounted to one axial end of peripheral wall portion 10 by being supported by holder assembly 20. Igniter 40 is installed so as to face the space inside the housing.

[0059] Igniter 40 is used to burn gas generating agent 60 by generating a flame, and is also referred to as a squib. Igniter 40 includes a base 41, an ignition section 42, and a pair of terminal pins 43. Base 41 is a portion that holds ignition section 42 and a pair of terminal pins 43, and at least one of the pair of terminal pins 43 is inserted into base 41. The pair of terminal pins 43 are used to electrically connect cylinder-shaped gas generator 1A to an external control unit (not shown) of a vehicle or the like.

[0060] Ignition unit 42 contains an ignition charge that ignites and burns to generate a flame when activated, and a resistor (bridge wire) for igniting the ignition charge. A pair of terminal pins 43 are connected to ignition unit 42 to ignite the ignition charge.

[0061] More specifically, ignition unit 42 includes a squib cup formed in a cup shape, the resistor described above is attached so as to connect the tips of a pair of terminal pins 43 inserted into this squib cup, and an ignition charge is loaded in the squib cup so as to surround or be close to this resistor. Furthermore, ignition unit 42 may be loaded with an enhancer charge as needed.

[0062] The resistor typically uses nichrome wire or resistance wire made of an alloy containing platinum and tungsten, and the ignition charge typically uses ZPP (zirconium-potassium perchlorate), ZWPP (zirconium-tungsten-potassium perchlorate), lead tricinate, etc. The transfer charge typically uses a metal powder / oxidizer composition such as B / KNO3, B / NaNO3, or Sr(NO3)2, a titanium hydride / potassium perchlorate composition, or a B / 5-aminotetrazole / potassium nitrate / molybdenum trioxide composition.

[0063] When a collision is detected, a predetermined amount of current flows through the resistor via the terminal pin 43. This current flow generates Joule heat in the resistor, causing the ignition charge to begin burning. The high-temperature particles generated by the combustion split open the squib cup containing the ignition charge. The time from when the current flows through the resistor to when the igniter 40 is activated is generally 2 milliseconds or less when nichrome wire is used for the resistor.

[0064] Igniter 40 is mounted to holder assembly 20 so that ignition portion 42 is positioned to protrude toward the interior of the housing. Therefore, when igniter 40 is activated, the ignition charge is ignited, causing the squib cup to split, and the squib cup opens as a result of this splitting.

[0065] 1, 4, and 5, a partition member 50 is inserted into the peripheral wall portion 10. The partition member 50 is a member for dividing the space inside the housing in the axial direction of the peripheral wall portion 10 so that the gas generating agent storage chamber S1 is located on one axial end side of the peripheral wall portion 10 and the filter chamber S2 is located on the other axial end side of the peripheral wall portion 10.

[0066] The partition member 50 has a substantially cylindrical plate-shaped annular wall portion 51 extending along the inner circumferential surface of the peripheral wall portion 10, and a substantially flat plate-shaped partition portion 52 closing one axial end of the annular wall portion 51. The annular wall portion 51 stands from the periphery of the partition portion 52 toward the gas generating agent storage chamber S1. The partition member 50 is arranged so that the main surface of the partition portion 52 on the filter chamber S2 side abuts against the filter 80.

[0067] The material of the partition member 50 is not particularly limited, but it is made of a metal member such as stainless steel, iron steel, aluminum alloy, or stainless alloy.

[0068] Scores 52a are provided on the main surface of the partition wall portion 52 that contacts the filter 80. The scores 52a are intended to allow the partition wall portion 52 to break and form an opening as the internal pressure of the gas generating agent storage chamber S1 increases due to combustion of the gas generating agent 60, and are configured, for example, by a plurality of grooves that are provided radially so as to intersect with one another. The scores 52a are provided in a portion of the filter 80 that faces the hollow portion 81.

[0069] The partition member 50 is assembled by being inserted into the peripheral wall portion 10 and then joined to the peripheral wall portion 10. The configuration in the vicinity of the partition member 50 will be described in detail later.

[0070] Within the space inside the housing, a gas generating agent 60, an autoignition agent 61, and a coil spring 70 are arranged in a space sandwiched between the holder assembly 20 and the partition member 50 (i.e., a gas generating agent storage chamber S1).

[0071] The coil spring 70 is disposed on the side of the gas generating agent storage chamber S1 where the partition member 50 is located, and the gas generating agent 60 is disposed between the holder assembly 20 and the coil spring 70. The autoignition agent 61 is disposed between the partition wall portion 52 of the partition member 50 and the coil spring 70 so as to abut against the partition wall portion 52.

[0072] The gas generating agent 60 is an agent that generates gas by being ignited and burning by thermal particles generated by the activation of the igniter 40. A non-azide gas generating agent is preferably used as the gas generating agent 60, and the gas generating agent 60 is generally configured as a molded body containing fuel, an oxidizer, and an additive.

[0073] The fuel may be, for example, a triazole derivative, a tetrazole derivative, a guanidine derivative, an azodicarbonamide derivative, a hydrazine derivative, or a combination thereof. Specifically, nitroguanidine, guanidine nitrate, cyanoguanidine, 5-aminotetrazole, or the like is preferably used.

[0074] Examples of 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.

[0075] Examples of additives include binders, slag formers, and combustion adjusters. Suitable binders include organic binders such as metal salts of carboxymethyl cellulose and stearates, and inorganic binders such as synthetic hydrotalcite and acid clay. Suitable slag formers include silicon nitride, silica, and acid clay. Suitable combustion adjusters include metal oxides, ferrosilicon, activated carbon, and graphite.

[0076] The shape of the molded body of the gas generating agent 60 may be various, including granular, pellet-like, cylindrical, or other granular shapes, as well as disk-like shapes. Furthermore, for cylindrical molded bodies, perforated molded bodies having through holes inside the molded body (for example, single-hole cylindrical shapes or multi-hole cylindrical shapes) are also used. These shapes are preferably selected appropriately depending on the specifications of the airbag device into which the cylindrical gas generator 1A is to be incorporated, and it is preferable to select an optimal shape depending on the specifications, such as a shape in which the rate of gas generation changes over time during combustion of the gas generating agent 60. Furthermore, in addition to the shape of the gas generating agent 60, it is preferable to select the size and filling amount of the molded body appropriately taking into consideration the linear burning velocity, pressure exponent, etc. of the gas generating agent 60.

[0077] The coil spring 70 is provided for the purpose of preventing the gas generating agent 60, which is made of a molded body, from being crushed by vibration, etc., and has a spring portion 71 formed by bending a metal wire and a pair of pressing portions 72 located at both ends of the spring portion 71.

[0078] The spring portion 71 is a generally cylindrical portion formed by spirally winding a metal wire. On the other hand, one of the pair of pressing portions 72 is provided at one end of the spring portion 71, and the other is provided at the other end of the spring portion 71. The pair of pressing portions 72 are configured to have a generally disk-like shape as a whole, for example, by arranging the metal wires generally parallel to each other at a predetermined interval, or by arranging the metal wires in a spiral shape at a predetermined interval. One of the pair of pressing portions 72 is in contact with the gas generating agent 60, and the other is in contact with the autoignition agent 61.

[0079] The coil spring 70 is sandwiched between the autoignition agent 61 and the gas generating agent 60 and is thereby compressed. Therefore, the gas generating agent 60 is elastically biased toward the holder assembly 20 by the coil spring 70, thereby preventing the gas generating agent 60 from moving inside the gas generating agent accommodating chamber S1. With this configuration, the gas generating agent 60 made of a molded body can be prevented from being crushed by vibration or the like.

[0080] Furthermore, when assembling the coil spring 70, the coil spring 70 is sandwiched and compressed 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.

[0081] The autoignition agent 61 is made of pellets formed into a flat, generally cylindrical shape. The autoignition agent 61 is arranged on the opposite side of the coil spring 70 from the side on which the gas generating agent 60 is located (i.e., on the filter 80 side), and is held by being sandwiched between the bulkhead 52 of the partition member 50 and the coil spring 70. As a result, the autoignition agent 61 is separated from the gas generating agent 60 by the coil spring 70.

[0082] Auto-ignition agent 61 is an agent that ignites automatically without the operation of igniter 40. More specifically, auto-ignition agent 61 spontaneously ignites at a lower temperature than gas generating agent 60, and is intended to prevent abnormal operation of cylinder-shaped gas generator 1A from being induced by external heating in the unlikely event of a fire or the like occurring in a vehicle or the like equipped with an airbag device incorporating cylinder-shaped gas generator 1A.

[0083] 1, within the space inside the housing, a filter 80 is disposed in the space sandwiched between the closing member 30 and the partition member 50 (i.e., the filter chamber S2). The filter 80 is made of a cylindrical member having a hollow portion 81 extending along a direction parallel to the axial direction of the peripheral wall portion 10, with one axial end face abutting against the closing member 30 and the other axial end face abutting against the partition wall portion 52 of the partition member 50.

[0084] The filter 80 functions as a cooling means for cooling the gas by removing the high temperature heat of the gas generated by the combustion of the gas generating agent 60 as the gas passes through the filter 80, and also functions as a removal means for removing slag (residue) and the like contained in the gas. As described above, by using the filter 80 made of a cylindrical member, the flow resistance to the gas flowing through the filter chamber S2 during operation is kept low, making it possible to achieve an efficient gas flow.

[0085] The filter 80 can be preferably made of an assembly of metal wire or metal mesh material made of stainless steel, iron, etc. Specifically, it can be made of a knitted wire mesh, a plain woven wire mesh, an assembly of crimped woven metal wire, or any of these compressed by a press.

[0086] A wound perforated metal plate or the like can also be used as the filter 80. In this case, examples of the perforated metal plate that can be used include expanded metal, which is made by cutting staggered slits in a metal plate and expanding the slits to form holes and process it into a mesh-like shape, and hook metal, which is made by drilling holes in a metal plate and flattening the burrs that form around the holes by crushing them.

[0087] A plurality of gas outlets 14 are provided along the circumferential and axial directions on the peripheral wall 10 at the portion that defines the filter chamber S2. These gas outlets 14 are for directing the gas that has passed through the filter 80 to the outside of the housing.

[0088] <Operation of Cylinder-Type Gas Generator> Next, referring to FIG. 1, the operation of the cylinder-type gas generator 1A according to the present embodiment during operation will be described.

[0089] Referring 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 collision detection means provided separately in the vehicle, and based on this, the igniter 40 is operated by energization from a control unit provided separately in the vehicle.

[0090] When the igniter 40 operates, the pressure in the ignition part 42 rises due to the combustion of the ignition powder or, in addition to this, the booster powder. As a result, the squib cup of the ignition part 42 cracks, and the hot particles generated by the combustion of the ignition powder or, in addition to this, the booster powder flow out to the outside of the ignition part 42. The hot particles that reach the gas generating agent 60 cause the gas generating agent 60 to burn, thereby generating a large amount of gas in the gas generating agent storage chamber S1.

[0091] 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, a break occurs in the portion of the partition member 50 where the score 52a is provided. As a result, an opening is formed in the partition member 50 at the portion facing the cavity 81 of the filter 80, and the gas generating agent storage chamber S1 and the filter chamber S2 are in a state of being connected through the opening.

[0092] 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 of the cavity 81 of the filter 80 and then changes its direction radially and flows through the inside of the filter 80. At that time, the gas is cooled by the heat being taken away by the filter 80, and the slag contained in the gas is removed by the filter 80.

[0093] 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 inside of an airbag provided adjacent to the cylinder-type gas generator 1A, and inflates and deploys the airbag. Note that the auto-ignition agent 61 burns together when the gas generating agent 60 burns.

[0094] <C. Detailed Configuration Near the Partition Member> As shown in FIGS. 1, 4, and 5, the partition member 50 has an annular wall portion 51 and a partition wall portion 52 as described above.

[0095] The annular wall portion 51 includes a contact portion 51a that contacts the inner peripheral surface of the peripheral wall portion 10, and a separated portion 51b that is positioned away from the inner peripheral surface of the peripheral wall portion 10 and has a gap G provided therebetween and the inner peripheral surface of the peripheral wall portion 10. The contact portion 51a extends along a direction parallel to the circumferential direction of the peripheral wall portion 10.

[0096] In the present embodiment, the contact portion 51a and the separated portion 51b are positioned adjacent to each other in the axial direction of the peripheral wall portion 10. Specifically, the separated portion 51b is continuously provided to the partition wall portion 52, and the contact portion 51a is continuously provided to an end portion on the side opposite to the partition wall portion 52 side among a pair of end portions of the separated portion 51b in the axial direction. In the cylinder-type gas generator 1A configured as described above, the gap G communicates with the filter chamber S2.

[0097] The separated portion 51b includes a first portion 51b1 as an inclined portion that inclines away from the inner peripheral surface of the peripheral wall portion 10 as it goes from one end portion side to the other end portion side in the axial direction of the peripheral wall portion 10 (that is, as it goes from the side where the holder assembly 20 is located to the side where the closing member 30 is located), and a second portion 51b2 that is continuous from an end portion located on the other end portion side of the first portion 51b1 and extends along a direction substantially parallel to the inner peripheral surface of the peripheral wall portion 10. The contact portion 51a is continuously provided to an end portion located on one end portion side of the first portion 51b1.

[0098] The partition member 50 configured as described above is press-fitted inside the peripheral wall portion 10 and fixed to the peripheral wall portion 10 by joining the annular wall portion 51 and the peripheral wall portion 10 by welding. Laser welding is used for welding the annular wall portion 51 and the peripheral wall portion 10. Note that this welding is not particularly limited to laser welding, and for example, electron beam welding or resistance welding can also be suitably used.

[0099] The welded portion 90 that welds the annular wall portion 51 and the peripheral wall portion 10 is provided to extend along the circumferential direction of the peripheral wall portion 10. The welded portion 90 penetrates the peripheral wall portion 10 in its thickness direction and also penetrates the annular wall portion 51 in its thickness direction.

[0100] The welded portion 90 is provided on a part of the separated portion 51b of the annular wall portion 51 and on the peripheral wall portion 10 of the portion facing a part of the separated portion 51b. By configuring in this way, at least a part of the gap G between the peripheral wall portion 10 and the separated portion 51b is filled by the welded portion 90. Therefore, the gap G is sealed by the welded portion 90, and the sealing property at this portion is ensured.

[0101] Also, since the welded portion 90 is provided on a part of the separated portion 51b of the annular wall portion 51 and on the peripheral wall portion 10 of the portion facing a part of the separated portion 51b as described above, at least a part of the welded portion 90 faces the gap G. By configuring in this way, it is possible to obtain the cylinder type gas generator 1A in which the generation of blow holes in the welded portion for welding the partition member and the housing is suppressed to improve the sealing property. This point will be described in detail later.

[0102] <D. Assembly procedure of the partition member to the peripheral wall portion> Figure 6 is a flow diagram showing the procedure for assembling the partition member to the peripheral wall portion of the cylinder-shaped gas generator shown in Figure 1. Figures 7 and 8 are schematic cross-sectional views for illustrating the procedure for assembling the partition member to the peripheral wall portion of the cylinder-shaped gas generator shown in Figure 1. Next, with reference to Figures 6 to 8 and the above-mentioned Figure 5, the procedure for assembling partition member 50 to peripheral wall portion 10 in cylinder-shaped gas generator 1A according to the present embodiment will be described.

[0103] 5 and 6, when assembling the partition member 50 to the peripheral wall 10 of the housing, first, in step ST1, the peripheral wall and the partition member are prepared. More specifically, the partition member 50 having the annular wall 51 and the partition wall 52 closing one axial end of the annular wall 51, and the cylindrical peripheral wall 10 of the housing are prepared.

[0104] The annular wall portion 51 includes a contact portion 51a that contacts the inner peripheral surface of the peripheral wall portion 10 when the partition member 50 is inserted into the peripheral wall portion 10 as described below, and a separation portion 51b that is positioned away from the inner peripheral surface of the peripheral wall portion 10, thereby providing a gap G between the inner peripheral surface of the peripheral wall portion 10 and the contact portion 51a (see Figure 8).

[0105] The outer diameter of the annular wall portion 51 that defines the opening surface of the partition member 50 is configured to be the same as or slightly larger than the inner diameter of the peripheral wall portion 10 .

[0106] Next, as shown in FIGS. 6 and 7, in step ST2, the partition member is inserted into the peripheral wall portion.

[0107] More specifically, first, the partition member 50 is positioned so that its opening surface is located on the opposite side to the peripheral wall portion 10 and the central axis of the annular wall portion 51 roughly overlaps with the central axis of the peripheral wall portion 10. Next, the partition member 50 thus positioned is press-fitted into the interior of the peripheral wall portion 10.

[0108] 6 and 8, in step ST3, with the partition member inserted into the peripheral wall portion, the annular wall portion is welded to the peripheral wall portion, thereby fixing the partition member to the housing.

[0109] More specifically, in a state where the partition member 50 is inserted into the peripheral wall portion 10, a laser LA is irradiated from a torch 100 of a laser welding machine toward a predetermined portion of the outer peripheral surface of the peripheral wall portion 10.

[0110] Simultaneously with this irradiation, the peripheral wall portion 10 is rotated in the direction of arrow DR shown in Fig. 8 around its central axis CL as the center of rotation. As a result, a weld 90 that welds the annular wall portion 51 and the peripheral wall portion 10 together is provided extending along the circumferential direction of the peripheral wall portion 10. Note that instead of rotating the peripheral wall portion 10, the torch 100 may be moved along the circumferential direction of the peripheral wall portion 10 while irradiating the laser LA.

[0111] The welding conditions for this laser welding are adjusted as appropriate so that the welded portion 90 is provided in a portion of the annular wall portion 51 that includes the spaced portion 51b. Examples of the irradiation conditions include the welding current, welding voltage, current application time, and irradiation position on the outer peripheral surface of the peripheral wall portion 10. Note that the clearance of the gap G between the portion of the peripheral wall portion 10 where the welded portion 90 will be provided and the spaced portion 51b opposite thereto is preferably 0.25 mm or less.

[0112] In this embodiment, the welded portion 90 is provided on a part of the spaced portion 51b of the annular wall portion 51 and on a part of the peripheral wall portion 10 facing the part of the spaced portion 51b. As a result, at least a part of the welded portion 90 faces the gap G.

[0113] By going through the steps ST1 to ST3 described above, the assembly of the partition member 50 to the peripheral wall portion 10 is completed.

[0114] In the manufacturing method of the cylinder type gas generator 1A described above, the case where the welded portion 90 is provided by laser welding has been exemplified. However, the welded portion 90 may be provided by other welding methods, for example, electron beam welding or resistance welding.

[0115] <E. Brackets><C. In the cylinder type gas generator 1A and its manufacturing method according to the present embodiment described above, as described above, the welded portion 90 that welds the annular wall portion 51 and the peripheral wall portion 10 is provided in the separated portion 51b of the annular wall portion 51. Thereby, at least a part of the welded portion 90 faces the gap G provided between the separated portion 51b and the inner peripheral surface of the peripheral wall portion 10.

[0116] By configuring in this way, when the annular wall portion 51 is welded to the peripheral wall portion 10, the gas generated at the welded portion 90 and its vicinity can be discharged toward the space including the gap G.

[0117] Therefore, it is possible to effectively suppress the occurrence of blow holes in the welded portion 90 or its vicinity due to the gas being confined at the interface between the peripheral wall portion 10 and the welded portion 90 and / or the interface between the annular wall portion 51 and the welded portion 90. As a result, the sealing performance of the welded portion 90 can be improved.

[0118] Therefore, by adopting the cylinder type gas generator 1A and its manufacturing method according to the present embodiment, it is possible to obtain a cylinder type gas generator in which the sealing performance of the welded portion for welding the partition member and the housing is improved.

[0119] Note that the effect of improving the sealing performance in the cylinder type gas generator 1A described above has been confirmed by the first verification test described later.

[0120] Furthermore, in cylinder-shaped gas generator 1A according to the present embodiment described above, the case has been exemplified in which the entire portion of annular wall portion 51 at which welded portion 90 is provided is configured from separated portion 51b, but welded portion 90 may be provided so as to straddle both abutting portion 51a and separated portion 51b. In other words, it is sufficient that welded portion 90 is provided in a portion of annular wall portion 51 that includes separated portion 51b, so that at least a portion of welded portion 90 faces gap G.

[0121] (First verification test) In the first verification test, a partition member 50X having a configuration partially different from that of the partition member 50 in the above-described embodiment was prepared, and the partition member 50X was used to investigate the relationship between the size of the clearance C between the separating portion 51b of the partition member 50X and the peripheral wall portion 10 and the sealing performance at the welded portion 90. Fig. 9 is a schematic cross-sectional view for explaining the first verification test. Fig. 10 is a table showing the results of the first verification test.

[0122] The partition member 50X used in this verification test differs from the partition member 50 in the configuration of the separation portion 51b. More specifically, in the partition member 50, as described above, the separation portion 51b includes a first portion 51b1 as an inclined portion and a second portion 51b2 as a portion extending along a direction substantially parallel to the inner circumferential surface of the peripheral wall portion 10, whereas in the partition member 50X, the separation portion 51b is composed only of the second portion 51b2 as a portion extending along a direction substantially parallel to the inner circumferential surface of the peripheral wall portion 10.

[0123] In this verification test, seven types of partition member 50X were prepared, each consisting of five samples, each with different magnitudes of the clearance C. The annular wall portion 51 of the partition member 50X was welded to the peripheral wall portion 10 so that the entire annular wall portion 51 at the portion where the welded portion 90 was provided was composed of the separation portion 51b. A clearance C of 0 mm means that the annular wall portion 51 of the partition member 50X does not include the separation portion 51b (i.e., the entire annular wall portion 51 is composed of the abutment portion 51a).

[0124] Next, a helium gas leak test was performed on each sample to confirm the presence or absence of helium gas leaks. To perform the helium gas leak test, a partition member 50X was fixed to the peripheral wall 10 to divide the internal space of the peripheral wall 10 into two. A workpiece consisting of the peripheral wall 10 and the partition member 50X was placed in a space under atmospheric pressure. One of the pair of ends of the peripheral wall 10 was chucked. The chucked space of the two spaces in the peripheral wall 10 was then evacuated. Helium gas was then sprayed toward the weld 90 from the unchucked space of the two spaces in the peripheral wall 10 and from the space located outside the peripheral wall 10. The gas leaking from the weld 90 and its vicinity toward the chucked space of the two spaces in the peripheral wall 10 was passed through a mass spectrometer, and the partial pressure of the helium gas contained in the leaked gas was measured. If the partial pressure of helium gas measured in this manner was greater than a predetermined value, it was determined that there was a helium gas leak at the welded portion 90 and its vicinity.

[0125] In this verification test, if there was a helium gas leak in at least one of the five samples, the result of the helium gas leak test for that type of partition member 50X was deemed to be a failure (NG), and if there was no helium gas leak in any of the five samples, the result of the helium gas leak test for that type of partition member 50X was deemed to be a pass (OK).

[0126] The results of this verification test shown in Fig. 10 confirmed that when clearance C is 0.025 mm or greater, a cylindrical gas generator can be provided that has no helium gas leakage and excellent sealing properties. Furthermore, the results of this verification test suggest that as long as clearance C exists, a cylindrical gas generator with excellent sealing properties can be provided, regardless of its size.

[0127] It should be noted that partition member 50X used in the present verification test can be used in place of partition member 50 used in cylinder-shaped gas generator 1A according to the embodiment described above. Even in such a configuration, effects similar to those described in the embodiment described above can be obtained, and a cylinder-shaped gas generator can be provided in which the sealing performance at the welded joint between the partition member and the housing is improved.

[0128] (Second verification test) In the second verification test, the relationship between the considerably long crimping length L1 of the peripheral wall portion 10 and the fixing strength of the closure member 30 to the peripheral wall portion 10 by the third crimping portion 13 was investigated. Fig. 11 is a table showing the results of the second verification test. The crimping length L1 and distance L2 shown in Fig. 11 are shown in Fig. 3.

[0129] In this verification test, five types of cylinder-shaped gas generators were prepared, each with three samples, differing only in crimping length L1 of peripheral wall portion 10. As described above, crimping length L1 is the distance in the axial direction of peripheral wall portion 10 between the end face of a pair of axial end faces of peripheral wall portion 10 on the side where blocking member 30 is located, and the end face of the pair of axial end faces of blocking member 30 on the side where the end face of peripheral wall portion 10 is located. Distance L2 in the axial direction of peripheral wall portion 10 between the valley bottom portion of third crimping portion 13 and the end face of the pair of axial end faces of blocking member 30 on the side where the end face of peripheral wall portion 10 is located was the same for all types of cylinder-shaped gas generators.

[0130] The peripheral wall portion 10 of the cylinder-shaped gas generator prepared in this verification test was made of a carbon steel pipe for mechanical structure, and had an outer diameter of 17.4 mm and a thickness of 1.0 mm. The outer diameter of peripheral wall portion 10 at the bottom of third crimped portion 13 was 16.15 mm. Note that in cylinder-shaped gas generators where crimping length L1 was 7.5 mm or more, peripheral wall portion 10 had straight portion 10b, but in cylinder-shaped gas generators where crimping length L1 was 6.5 mm or more, peripheral wall portion 10 did not have straight portion 10b.

[0131] In this verification test, each sample was subjected to a hydroburst tester to check whether the blocking member 30 had fallen off.

[0132] More specifically, each sample was subjected to a hydroburst test machine to check whether the closing member 30 fell off or whether fracture occurred in the peripheral wall 10 at a portion other than the third crimped portion 13. In the former case, the strength of the fixing of the closing member 30 to the peripheral wall 10 by the third crimped portion 13 was determined to be lower than the strength of the base material of the material constituting the peripheral wall 10, and the result of the hydroburst test was determined to be fail (NG). In the latter case, the strength of the fixing of the closing member 30 to the peripheral wall 10 by the third crimped portion 13 was determined to be higher than the strength of the base material of the material constituting the peripheral wall 10, and the result of the hydroburst test was determined to be pass (OK).

[0133] The results of this verification test shown in Figure 11 confirmed that when the crimping length L1 is 7.5 mm or more, the blocking member 30 does not fall off and the fixing strength of the blocking member 30 by the third crimping portion 13 is sufficiently ensured to produce a cylinder-shaped gas generator.

[0134] (First Modification) Figure 12 is an enlarged cross-sectional view of the vicinity of the partition member of a cylinder-shaped gas generator according to a first modified example. Cylinder-shaped gas generator 1A1 according to the first modified example based on the embodiment described above will now be described with reference to Figure 12. Note that Figure 12 shows only peripheral wall portion 10, partition member 50 and welded portion 90 (the same applies to Figures 13 to 15 described later).

[0135] 12, when compared with cylinder-shaped gas generator 1A according to the above-described embodiment, cylinder-shaped gas generator 1A1 according to the present modification differs only in the configuration of partition member 50. More specifically, in cylinder-shaped gas generator 1A1 according to the present modification, separating portion 51b of annular wall portion 51 of partition member 50 is constituted only by first portion 51b1 as an inclined portion.

[0136] Even when configured in this manner, effects similar to those described in the above-mentioned embodiment can be obtained, and a cylinder-shaped gas generator can be provided in which the sealing performance at the welded joint where the partition member and the housing are welded can be improved.

[0137] (Second Modification) Fig. 13 is an enlarged cross-sectional view of the vicinity of the partition member of a cylinder-shaped gas generator according to Modification 2. Hereinafter, with reference to Fig. 13, a cylinder-shaped gas generator 1A2 according to Modification 2 based on the above-described embodiment will be described.

[0138] As shown in FIG. 13, cylinder-shaped gas generator 1A2 according to this modification differs from cylinder-shaped gas generator 1A according to the embodiment described above only in the configuration of partition member 50.

[0139] More specifically, in cylinder-shaped gas generator 1A2 according to the present modification, spaced portion 51b of annular wall portion 51 of partition member 50 includes first spaced portion 51b11 and second spaced portion 51b12. First spaced portion 51b11 and second spaced portion 51b12 are both configured only by second portion 51b2 extending along a direction substantially parallel to the inner circumferential surface of peripheral wall portion 10.

[0140] The first spaced portion 51b11, the contact portion 51a, and the second spaced portion 51b12 are provided continuously in this order in the axial direction of the peripheral wall portion 10 from the side closer to the partition portion 52. The welded portion 90 is provided on a part of the second spaced portion 51b12 and on a part of the peripheral wall portion 10 facing the part of the second spaced portion 51b12.

[0141] In cylinder-shaped gas generator 1A2 configured in this manner, gap G provided between the inner circumferential surface of circumferential wall portion 10 and second separated portion 51b12 communicates with gas generating agent storage chamber S1.

[0142] Even when configured in this manner, effects similar to those described in the above-mentioned embodiment can be obtained, and a cylinder-shaped gas generator can be provided in which the sealing performance at the welded joint where the partition member and the housing are welded can be improved.

[0143] In addition, in cylinder-shaped gas generator 1A2 according to this modified example, the example has been given in which welded portion 90 is provided on a part of second separated portion 51b12 and on a part of peripheral wall portion 10 facing the part of second separated portion 51b12, but welded portion 90 may also be provided on a part of first separated portion 51b11 and on a part of peripheral wall portion 10 facing the part of first separated portion 51b11.

[0144] (Third Modification) Fig. 14 is an enlarged cross-sectional view of the vicinity of the partition member of a cylinder-shaped gas generator according to Modification 3. Hereinafter, with reference to Fig. 14, a cylinder-shaped gas generator 1A3 according to Modification 3 based on the above-described embodiment will be described.

[0145] As shown in FIG. 14, cylinder-shaped gas generator 1A3 according to this modification differs from cylinder-shaped gas generator 1A according to the embodiment described above only in the configuration of partition member 50.

[0146] More specifically, in cylinder-shaped gas generator 1A3 according to the present modification, contact portion 51a of annular wall portion 51 of partition member 50 includes first contact portion 51a1 and second contact portion 51a2. Separated portion 51b is constituted only by second portion 51b2 extending along a direction approximately parallel to the inner circumferential surface of peripheral wall portion 10.

[0147] The second contact portion 51a2, the spaced portion 51b, and the first contact portion 51a1 are provided continuously in this order in the axial direction of the peripheral wall portion 10, starting from the side closer to the partition wall portion 52. In other words, the spaced portion 51b is positioned so as to be sandwiched between the first contact portion 51a1 and the second contact portion 51a2. The welded portion 90 is provided in a part of the spaced portion 51b and in a part of the peripheral wall portion 10 facing the part of the spaced portion 51b.

[0148] In cylinder-shaped gas generator 1A3 configured in this manner, gap G does not communicate with either gas generating agent storage chamber S1 or filter chamber S2.

[0149] Even when configured in this manner, effects similar to those described in the above-mentioned embodiment can be obtained, and a cylinder-shaped gas generator can be provided in which the sealing performance at the welded joint where the partition member and the housing are welded can be improved.

[0150] (Fourth Modification) Fig. 15 is an enlarged cross-sectional view of the vicinity of the partition member of a cylinder-shaped gas generator according to Modification 4. Hereinafter, with reference to Fig. 15, a cylinder-shaped gas generator 1A4 according to Modification 4 based on the above-described embodiment will be described.

[0151] As shown in FIG. 15, cylinder-shaped gas generator 1A4 according to this modified example differs from cylinder-shaped gas generator 1A according to the embodiment described above in the configuration of partition member 50 and the configuration of welded portion 90.

[0152] More specifically, in cylinder-shaped gas generator 1A4 according to this modified example, separation portion 51b of annular wall portion 51 of partition member 50 is constituted only by second portion 51b2 extending along a direction approximately parallel to the inner circumferential surface of peripheral wall portion 10.

[0153] Furthermore, in cylinder-shaped gas generator 1A4, separated portion 51b is configured to be considerably thick. Due to this, in cylinder-shaped gas generator 1A4, welded portion 90 penetrates peripheral wall portion 10 in the thickness direction, but does not penetrate separated portion 51b in the thickness direction.

[0154] Even when configured in this manner, effects similar to those described in the above-mentioned embodiment can be obtained, and a cylinder-shaped gas generator can be provided in which the sealing performance at the welded joint where the partition member and the housing are welded can be improved.

[0155] (Fifth Modification) FIG. 16 is an enlarged cross-sectional view of the vicinity of a partition member of a cylinder-shaped gas generator according to a fifth modified example. In detail, FIG. 16(A) is a schematic view of the partition member as viewed from the annular wall portion side in the axial direction. FIG. 16(B) is a schematic cross-sectional view taken along line XVIB-XVIB shown in FIG. 16(A). FIG. 16(C) is a schematic cross-sectional view taken along line XVIC-XVIC shown in FIG. 16(A). Hereinafter, with reference to FIG. 16, a cylinder-shaped gas generator 1A5 according to a fifth modified example based on the embodiment described above will be described. Note that only partition member 50 is shown in FIG. 16(A). In FIGS. 16(B) and 16(C), only peripheral wall portion 10, partition member 50, and welded portion 90 are shown.

[0156] As shown in Figures 16(A) to 16(C), cylinder-shaped gas generator 1A5 according to this modified example differs from cylinder-shaped gas generator 1A according to the embodiment described above in the configuration of partition member 50.

[0157] More specifically, in cylinder-shaped gas generator 1A5 according to the present modification, annular wall portion 51 of partition member 50 includes a plurality of contact portions 51a and a plurality of spaced portions 51b. The area ratio of spaced portions 51b to annular wall portion 51 is configured to be considerably larger than the area ratio of a plurality of contact portions 51a to annular wall portion 51.

[0158] The plurality of contact portions 51a and the plurality of spaced portions 51b all extend in a direction parallel to the axial direction of the peripheral wall portion 10. The plurality of spaced portions 51b are each formed of only second portions 51b2 extending in a direction substantially parallel to the inner peripheral surface of the peripheral wall portion 10.

[0159] In cylinder-shaped gas generator 1A5 configured in this manner, a plurality of contact portions 51a and a plurality of spaced portions 51b are positioned so as to be alternately adjacent to each other in the circumferential direction of peripheral wall portion 10. Furthermore, gaps G provided between the inner circumferential surface of peripheral wall portion 10 and each of a plurality of spaced portions 51b communicate with both gas generating agent storage chamber S1 and filter chamber S2.

[0160] Even when configured in this manner, effects similar to those described in the above-mentioned embodiment can be obtained, and a cylinder-shaped gas generator can be provided in which the sealing performance at the welded joint where the partition member and the housing are welded can be improved.

[0161] (Sixth Modification) Fig. 17 is an enlarged cross-sectional view of the vicinity of a partition member of a cylinder-shaped gas generator according to a sixth modified example. In detail, Fig. 17(A) is a schematic view of the partition member as viewed from the annular wall portion side in the axial direction. Fig. 17(B) is a schematic cross-sectional view taken along line XVIIB-XVIIB shown in Fig. 17(A). Hereinafter, with reference to Fig. 17, a cylinder-shaped gas generator 1A6 according to a sixth modified example based on the embodiment described above will be described. Note that Fig. 17(A) shows only partition member 50. Fig. 17(B) shows only peripheral wall portion 10, partition member 50 and welded portion 90.

[0162] As shown in Figures 17(A) and 17(B), cylinder-shaped gas generator 1A6 according to this modified example differs from cylinder-shaped gas generator 1A according to the embodiment described above in the configuration of partition member 50.

[0163] More specifically, in cylinder-shaped gas generator 1A6 according to the present modification, annular wall portion 51 of partition member 50 includes a plurality of contact portions 51a and a plurality of spaced portions 51b. The area ratio of a plurality of contact portions 51a to annular wall portion 51 is generally the same as the area ratio of a plurality of spaced portions 51b to annular wall portion 51.

[0164] The plurality of contact portions 51a and the plurality of spaced portions 51b all extend in a direction parallel to the axial direction of the peripheral wall portion 10. The plurality of spaced portions 51b are each formed of only second portions 51b2 extending in a direction substantially parallel to the inner peripheral surface of the peripheral wall portion 10.

[0165] In cylinder-shaped gas generator 1A6 configured in this manner, a plurality of contact portions 51a and a plurality of spaced portions 51b are positioned so as to be alternately adjacent to each other in the circumferential direction of peripheral wall portion 10. Furthermore, gaps G provided between the inner peripheral surface of peripheral wall portion 10 and each of a plurality of spaced portions 51b communicate with both gas generating agent storage chamber S1 and filter chamber S2.

[0166] Even when configured in this manner, effects similar to those described in the above-mentioned embodiment can be obtained, and a cylinder-shaped gas generator can be provided in which the sealing performance at the welded joint where the partition member and the housing are welded can be improved.

[0167] (Other forms, etc.) In the above-described embodiment and its modified examples, a holder assembly including a metal first holder having a function of primarily holding an igniter, a resin second holder having a function of primarily functioning as a directionality imparting member, and a resin third holder having a function of primarily forming a female connector portion has been described as an example, but instead of such a holder assembly, a holder formed of a single member may be used. Also, this holder does not necessarily have to function as a directionality imparting member.

[0168] Furthermore, the shape, size, number, placement position, etc. of each component disclosed in the above-described embodiment and its modified examples can naturally be modified in various ways within the scope that does not deviate from the spirit of the present invention.

[0169] Furthermore, in the above-mentioned embodiment and its modified examples, the present invention has been described as being applied to a cylinder-type gas generator incorporated in a side airbag device, but the application of the present invention is not limited to this, and the present invention can also be applied to cylinder-type gas generators incorporated in curtain airbag devices, knee airbag devices, seat cushion airbag devices, etc., and so-called T-shaped gas generators which have an elongated outer shape similar to a cylinder-type gas generator.

[0170] As such, the above-described embodiments and their modifications disclosed herein are illustrative in all respects and are not limiting. The technical scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0171] REFERENCE SIGNS 1A, 1A1 to 1A6: cylindrical gas generator, 10: peripheral wall portion, 10b: straight portion, 11: first crimped portion, 12: second crimped portion, 13: third crimped portion, 14: gas outlet, 20: holder assembly, 20A: first holder, 20B: second holder, 20C: third holder, 21: first body portion, 21a: first housing portion, 21b: crimped portion, 22: annular protrusion, 23: second body portion, 23a: second housing portion, 24: protrusion portion, 26: lid portion, 27: third body portion, 27a: third housing portion, 28: sealing member, 30: blocking member, 40: igniter, 41: base portion, 42: ignition portion, 43: terminal pin, 50, 50X: partition member, 51: annular wall portion, 51a: abutment portion, 51a1 First contact portion, 51a2 second contact portion, 51b separation portion, 51b1 first portion, 51b2 second portion, 51b11 first separation portion, 51b12 second separation portion, 52 partition portion, 52a score, 60 gas generating agent, 61 auto-ignition agent, 70 coil spring, 71 spring portion, 72 pressing portion, 80 filter, 81 cavity portion, 90 welding portion, 100 torch, G gap, LA laser, S1 gas generating agent storage chamber, S2 filter chamber.

Claims

1. a housing having a cylindrical peripheral wall portion whose one axial end and the other axial end are closed, and containing therein a gas generating agent storage chamber in which a gas generating agent is stored and a filter chamber in which a filter is disposed; a partition member that is inserted into the peripheral wall portion so that the gas generating agent storage chamber is located on the one end side and the filter chamber is located on the other end side, thereby dividing the interior space of the housing in the axial direction of the peripheral wall portion; an igniter attached to the one end of the peripheral wall portion, the partition member has an annular wall portion extending along an inner circumferential surface of the circumferential wall portion, and a partition wall portion closing one axial end of the annular wall portion, the partition member is fixed to the housing by welding the annular wall portion and the peripheral wall portion together, the annular wall portion includes a contact portion that contacts the inner circumferential surface of the peripheral wall portion, and a separation portion that is located apart from the inner circumferential surface of the peripheral wall portion to provide a gap between the contact portion and the inner circumferential surface of the peripheral wall portion, a weld that welds the annular wall portion and the peripheral wall portion together is provided in a portion of the annular wall portion that includes the separation portion, so that at least a portion of the weld faces the gap.

2. The gas generator according to claim 1 , wherein the abutting portion and the spaced portion are positioned adjacent to each other in the axial direction.

3. the separation portion includes an inclined portion that inclines so as to move away from the inner circumferential surface of the peripheral wall portion as it moves from the one end side to the other end side, and a portion that continues from an end portion located on the other end side of the inclined portion and extends along a direction substantially parallel to the inner circumferential surface of the peripheral wall portion, 3. The gas generator according to claim 2, wherein the abutting portion is provided contiguous with an end portion of the inclined portion located on the one end side.

4. the abutment portion includes a first abutment portion and a second abutment portion located closer to the other end portion in the axial direction than the first abutment portion, The gas generator according to claim 2 , wherein the spaced portion is positioned so as to be sandwiched between the first contact portion and the second contact portion in the axial direction.

5. The gas generator according to claim 1 , wherein the abutting portion and the spaced portion are positioned adjacent to each other in the circumferential direction of the peripheral wall portion.

6. 6. The gas generator according to claim 1, wherein the gap communicates with the gas generating agent storage chamber or the filter chamber.

7. a step of inserting a partition member having an annular wall portion and a partition wall portion closing one axial end of the annular wall portion into a cylindrical peripheral wall portion of the housing; and welding the annular wall portion to the peripheral wall portion with the partition member inserted into the peripheral wall portion to fix the partition member to the housing, When the partition member is inserted into the peripheral wall portion, the annular wall portion includes an abutting portion that abuts against an inner peripheral surface of the peripheral wall portion, and a separating portion that is located apart from the inner peripheral surface of the peripheral wall portion, thereby providing a gap between the abutting portion and the inner peripheral surface of the peripheral wall portion, a welding portion that welds the annular wall portion to the peripheral wall portion, the welding portion being provided on a portion of the annular wall portion that includes the separated portion, such that at least a part of the welding portion that welds the annular wall portion to the peripheral wall portion faces the gap.

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