Gas generator

Abstract

A gas generator (1A) comprises a metal housing main body (10), a holder assembly (20), and an igniter (40). The holder assembly (20) includes a metal first holder (20A) that holds a base portion (41) of the igniter (40), and a resin second holder (20B) that accommodates an ignition unit (41) of the igniter (40). The first holder (20A) is fixed to the housing main body (10) by being sandwiched between a first crimped portion (11) and a second crimped portion (12) provided in the housing main body (10). The first crimped portion (11) is covered by and comes into pressure contact with a second body portion (23) of the second holder (20B). The second holder (20B) further includes a lid portion (26) that separates a gas generating agent (60) from the ignition unit (42), and the lid portion (26) is disposed at a distance from the ignition unit (42).

Description

Gas generator

[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 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.

[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 combustion chamber containing a gas generating agent is provided on the one end side, and 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 the part that defines the filter chamber.

[0006] In a cylinder-shaped gas generator configured in this manner, gas generated in the combustion 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 outlet.

[0007] Here, in a cylinder-type gas generator, the igniter and gas generating agent are arranged along the axial direction of the housing, and therefore, if the gas generating agent is arranged in contact with or close to an ignition portion, which is a portion of the igniter where an ignition charge is loaded, there is a concern that when the ignition portion ruptures upon activation, the gas generating agent in the portion arranged in contact with or close to the ignition portion may hinder the rupture of the ignition portion. If the rupture of the ignition portion is hindered, there is a risk that the propagation of thermal particles (i.e., flame) generated in the igniter to the gas generating agent may be delayed or that the thermal particles may be biased in the traveling direction, resulting in problems such as variations in the time from the point in time when the igniter is activated until the gas starts to be ejected to the outside through the gas ejection port and variations in the combustion characteristics of the gas generating agent itself.

[0008] In order to avoid such problems, in the cylinder-type gas generators disclosed in, for example, Patent Publication No. 2021-195020 (Patent Document 1) and Patent Publication No. 2022-144932 (Patent Document 2), a coil spring for elastically biasing the gas generating agent is placed at the end of the combustion chamber on the side where the igniter is provided, and the length of the coil spring is adjusted so that a portion of the coil spring protrudes toward the gas generating agent beyond the ignition portion, thereby ensuring a distance between the gas generating agent and the igniter.

[0009] Furthermore, in a cylinder-type gas generator, it is important to efficiently guide the thermal particles generated by the igniter during operation to the gas generating agent, and a directivity imparting member is sometimes installed around the igniter as a guide to impart directionality to the direction of travel of the thermal particles generated in the ignition portion. Typically, the directivity imparting member has a cylindrical shape that surrounds the ignition portion, and is installed inside the housing so as to fill the gap between the peripheral wall of the housing and the ignition portion.

[0010] Literature that discloses a specific configuration of a cylinder-shaped gas generator equipped with such a directionality imparting member includes, for example, Japanese Patent Application Laid-Open No. 2017-1588 (Patent Document 3) and Japanese Patent Application Laid-Open No. 2017-81343 (Patent Document 4).

[0011] JP 2021-195020 A JP 2022-144932 A JP 2017-1588 A JP 2017-81343 A

[0012] However, when the configurations disclosed in Patent Documents 1 and 2 are adopted, differences in the degree of compressive deformation of the coil spring are likely to occur due to dimensional variations of various parts during assembly, and it is inevitable that there will be individual differences, albeit slight, in the distance between the igniter and the gas generating charge. Therefore, in order to more precisely manage the distance between the igniter and the gas generating charge, it is necessary to adopt an assembly structure other than an assembly structure using such a coil spring.

[0013] Furthermore, when considering the above-mentioned other assembly structures, if it is assumed that the cylinder-shaped gas generator is further equipped with the above-mentioned directionality imparting member, the directionality imparting member will be disposed in the vicinity of the igniter and the gas generating charge, and therefore it will be necessary to fix the directionality imparting member stably and immovably inside the housing, and it is essential to consider this point as well. Furthermore, when considering the above-mentioned other assembly structures, it is naturally preferable that the assembly structure is not complicated from the standpoint of reducing manufacturing costs.

[0014] Therefore, the present invention has been made in consideration of the above-mentioned problems, and has an object to provide a gas generator that can stably obtain a desired gas output while suppressing an increase in manufacturing costs.

[0015] A gas generator according to the present invention includes a housing body, a holder assembly, and an igniter. The housing is a cylindrical metal member containing a combustion chamber therein that houses a gas generating agent. The holder assembly is inserted into the axial open end of the housing body and includes a hollow portion extending parallel to the axial direction of the housing body. The igniter includes an ignition portion loaded with an ignition charge, a terminal pin connected to the ignition portion, and a base portion through which the terminal pin is inserted and that supports both the ignition portion and the terminal pin, and at least a portion of the igniter is disposed inside the hollow portion with the ignition portion located on the combustion chamber side and the terminal pin located opposite the combustion chamber side. The holder assembly includes a metal first holder that receives the base to hold the igniter, and a resin second holder that is located on the combustion chamber side as viewed from the first holder and that houses the ignition portion. The first holder includes a cylindrical first body defining the hollow portion and an annular protrusion protruding from the first body along the radial direction of the housing body, and the second holder includes a cylindrical second body defining the hollow portion. The housing body has a first crimped portion tapering radially inward and a second crimped portion located on the open end side as viewed from the first crimped portion and tapering radially inward. The first holder is fixed to the housing body by sandwiching the annular protrusion between the first crimped portion and the second crimped portion in the axial direction of the housing body. The first crimped portion is covered by the second body and is in pressure contact with at least a portion of the outer circumferential surface of the second body. The second holder further has a lid portion that separates the gas generating agent from the ignition portion by closing at least a portion of the hollow portion located on the opposite side of the base side from the ignition portion, and the lid portion is positioned at a distance from the ignition portion along the axial direction of the housing body.

[0016] According to the present invention, it is possible to provide a gas generator that can stably obtain a desired gas output while suppressing an increase in manufacturing costs.

[0017] FIG. 1 is a schematic diagram of a cylinder-shaped gas generator according to Embodiment 1. 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 partition member of the cylinder-shaped gas generator shown in FIG. 1. FIG. 4 is a perspective view of a second holder shown in FIG. 1. FIG. 5 is a plan view, a bottom view and a cross-sectional view of the second holder shown in FIG. 1. FIG. 6 is a schematic cross-sectional view showing a procedure for assembling a holder assembly in the cylinder-shaped gas generator shown in FIG. 1 and a procedure for assembling the holder assembly to a housing main body. FIG. 7 is a cross-sectional view of the cylinder-shaped gas generator shown in FIG. 1. FIG. 8 is an enlarged cross-sectional view of a main part of the cylinder-shaped gas generator shown in FIG. 1. FIG. 9 is an enlarged cross-sectional view of the vicinity of an igniter of a cylinder-shaped gas generator according to Embodiment 2.

[0018] 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 designated by the same reference numerals in the drawings, and their description will not be repeated.

[0019] (Embodiment 1) Fig. 1 is a schematic diagram of a cylinder-shaped gas generator according to an embodiment. Figs. 2 and 3 are enlarged cross-sectional views of the vicinity of an igniter and the vicinity of a partition member, respectively, of the cylinder-shaped gas generator shown in Fig. 1. First, with reference to Figs. 1 to 3, the configuration of cylinder-shaped gas generator 1A according to the present embodiment will be described.

[0020] 1 to 3, 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 housing main body 10, holder assembly 20, closing member 30, and partition member 50, of which housing main body 10, holder assembly 20, and closing member 30 define the outer shell of the housing.

[0021] The housing body 10, holder assembly 20, and closing member 30, which define the outer shell of the housing, accommodate internal components such as an igniter 40, a gas generating agent 60, an auto-ignition agent 61, a coil spring 70, and a filter 80, and in addition, the above-mentioned partition member 50, which is also an internal component, is disposed inside the housing. Also located inside the housing are a combustion chamber S1, which accommodates the gas generating agent 60, the auto-ignition agent 61, and the coil spring 70, which are among the above-mentioned internal components, and a filter chamber S2, which accommodates the filter 80.

[0022] Here, 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. The first holder 20A is a member that mainly holds the igniter 40, the second holder 20B mainly functions as a directionality imparting member, and the third holder 20C is a member that mainly constitutes a female connector. Details of the holder assembly 20 will be described later.

[0023] The housing body 10 forms the peripheral wall of the housing and is made of a long, cylindrical member with openings at both axial ends. As described above, the holder assembly 20 has the first holder 20A, the second holder 20B, and the third holder 20C, and when viewed as a whole, is made of a substantially cylindrical member with a hollow portion extending in a direction parallel to the axial direction of the housing body 10. The closing member 30 is made of a substantially disk-shaped member.

[0024] The housing body 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 housing body 10 may also be made of an electric resistance welded pipe such as STKM.

[0025] In particular, when the housing body 10 is constructed from a press-formed rolled steel plate or an electric-welded pipe, the housing body 10 can be formed more cheaply and easily than when metal components such as stainless steel or steel are used, and the weight can be significantly reduced.

[0026] On the other hand, the first holder 20A of the holder assembly 20 and the closing member 30 are made of metal members such as stainless steel, iron steel, aluminum alloy, stainless alloy, or the like.

[0027] The holder assembly 20 is fixed to the housing body 10 so as to close one axial open end of the housing body 10. Specifically, with the holder assembly 20 inserted into the one open end of the housing body 10, a predetermined position of the housing body 10 is reduced in diameter radially inward toward the holder assembly 20, and another predetermined position of the housing body 10 is reduced in diameter radially inward toward the holder assembly 20, thereby crimping and fixing the holder assembly 20 to the housing body 10. As a result, one axial end of the housing is defined by the holder assembly 20.

[0028] The blocking member 30 is fixed to the housing body 10 so as to close the other axial open end of the housing body 10. Specifically, the blocking member 30 is inserted into the other open end of the housing body 10, with one axial end face of the blocking member 30 abutting against the filter 80, and then a predetermined position of the housing body 10 is reduced in diameter radially inward toward the other axial end face of the blocking member 30, thereby crimping and fixing the blocking member 30 to the housing body 10. In this way, the other axial end of the housing is defined by the blocking member 30.

[0029] Here, these crimping fixations are called eight-way crimping, which reduces the diameter of the housing body 10 approximately uniformly inward in the radial direction. By performing this eight-way crimping, the housing body 10 is provided with first crimping portions 11 and second crimping portions 12 for fixing the holder assembly 20, and a third crimping portion 13 for fixing the closing member 30. This brings the housing body 10 into direct contact with the holder assembly 20 and the closing member 30, respectively, preventing gaps from occurring between them. The fixation of the holder assembly 20 to the housing body 10 will be described in more detail later.

[0030] The assembly structure of the closing member 30 to the housing main body 10 is not limited to the assembly structure described above, and other assembly structures may be adopted. Furthermore, the housing main body 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.

[0031] 1 and 2, the igniter 40 is mounted to the one axial end of the housing by being supported by the holder assembly 20. The igniter 40 is used to combust the gas generating agent 60, and is installed so as to face the interior space of the housing.

[0032] Igniter 40 is for generating a flame, and is also referred to as a squib. Igniter 40 includes a base 41, an ignition portion 42, and a pair of terminal pins 43. Base 41 is a portion that holds ignition portion 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 for electrically connecting cylinder-shaped gas generator 1A to an external control unit (not shown) of a vehicle or the like.

[0033] The 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 the ignition unit 42 to ignite the ignition charge.

[0034] 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 ignition charge as needed.

[0035] Here, the resistor is generally a nichrome wire or a resistance wire made of an alloy containing platinum and tungsten, and the ignition charge is generally ZPP (zirconium potassium perchlorate), ZWPP (zirconium tungsten potassium perchlorate), lead tricinate, etc. Furthermore, the transfer charge is B / KNO ３ , B / NaNO ３ , Sr(NO ３ ) ２ Examples of the composition that can be used include a composition consisting of a metal powder / oxidizer, such as titanium hydride / potassium perchlorate, and a composition consisting of B / 5-aminotetrazole / potassium nitrate / molybdenum trioxide.

[0036] When a collision is detected, a predetermined amount of current flows through the resistor via the terminal pin 43. This current flow through the resistor generates Joule heat, which causes the ignition charge to start 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.

[0037] Igniter 40 is fixed to holder assembly 20 with its ignition portion 42 positioned to protrude further toward the combustion chamber S1 side than base portion 41, and with a portion of it disposed inside the hollow portion of holder assembly 20. As a result, igniter 40 has its ignition portion 42 positioned on the combustion chamber S1 side, and its terminal pin 43 positioned on the opposite side from the combustion chamber S1 side.

[0038] Here, a seal member 28 made of an O-ring or the like is interposed at a predetermined position between holder assembly 20 and igniter 40, whereby the gap between holder assembly 20 and igniter 40 is filled with seal member 28, thereby sealing the gap. By configuring in this manner, it is possible to ensure airtightness in that portion, the details of which will be described later.

[0039] 1 and 3, a partition member 50, which constitutes part of the housing as described above, is disposed at a predetermined position in the space inside the housing. The partition member 50 is a member for dividing the space inside the housing in the axial direction into a combustion chamber S1 and a filter chamber S2.

[0040] The partition member 50 has a cylindrical shape with a bottom and is made of a metal member such as stainless steel, iron steel, aluminum alloy, or stainless alloy. The partition member 50 has a flat partition wall portion 51 arranged perpendicular to the axial direction of the housing body 10, and a cylindrical annular wall portion 52 standing from the periphery of the partition wall portion 51 toward the combustion chamber S1. The partition member 50 is arranged so that the outer main surface of the partition wall portion 51 abuts against the filter 80, and the outer peripheral surface of the annular wall portion 52 abuts against the inner peripheral surface of the housing body 10.

[0041] Scores 51a are provided on the main surface of the partition wall 51 that contacts the filter 80. The scores 51a are intended to cause the partition wall 51 to break and form an opening as the internal pressure of the combustion 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 51a are provided in a portion of the filter 80 that faces the hollow portion 81.

[0042] The partition member 50 is assembled by being inserted into the housing main body 10 and then joined to the housing main body 10. More specifically, the partition member 50 is press-fitted into the housing main body 10, and is fixed to the housing main body 10 by joining the annular wall portion 52 of the partition member 50 to the housing main body 10 at or near the contact portion between them, such as by welding.

[0043] As a result, a weld 90 extending circumferentially of the housing is provided in the portion of the housing corresponding to the portion into which the partition member 50 is inserted, and this weld 90 fills the gap between the housing main body 10 and the partition member 50. As a result, the gap is sealed by the weld 90, making it possible to ensure airtightness in that portion. Note that electron beam welding, laser welding, resistance welding, or the like can be suitably used to weld the housing main body 10 and the partition member 50 together.

[0044] Here, the assembly structure of the partition member 50 to the housing main body 10 is not limited to the assembly structure using press-fitting and welding described above, and other assembly structures may be adopted. In such cases, airtightness between the housing main body 10 and the partition member 50 can be ensured by providing an O-ring or the like at an appropriate position.

[0045] As shown in Figures 1 to 3, within the space inside the housing, a gas generating agent 60, an auto-ignition agent 61, and a coil spring 70 are arranged in the space sandwiched between the holder assembly 20 and the partition member 50 (i.e., the combustion chamber S1).

[0046] Of these, the coil spring 70 is disposed on the side of the combustion 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. In addition, the auto-ignition agent 61 is disposed between the partition member 50 and the coil spring 70 so as to abut against the partition member 50.

[0047] 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 a fuel, an oxidizer, and an additive.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] The shape of the molded body of gas generating agent 60 may be various, including granular, pellet-like, cylindrical, or other granular shapes, and disk-like shapes. Furthermore, for cylindrical molded bodies, perforated molded bodies having through holes inside the molded body (for example, a single-hole cylindrical shape or a multi-hole cylindrical shape) are also used. These shapes are preferably selected appropriately depending on the specifications of the airbag device into which cylindrical gas generator 1A is to be incorporated. For example, 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 gas generating agent 60. Furthermore, in addition to the shape of 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 gas generating agent 60.

[0052] 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.

[0053] The spring portion 71 is a generally cylindrical portion formed by spirally winding a metal wire. 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 overall, 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.

[0054] Here, 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 combustion chamber S1. Therefore, with this configuration, it is possible to prevent the gas generating agent 60, which is made of a molded body, from being crushed by vibration or the like.

[0055] 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.

[0056] The autoignition agent 61 is made of pellets formed into a flat, generally cylindrical shape. The autoignition agent 61 is disposed 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 51 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.

[0057] Auto-ignition agent 61 is an agent that ignites automatically without depending on the operation of igniter 40. More specifically, auto-ignition agent 61 spontaneously ignites at a temperature lower than that of 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.

[0058] 1 and 3 , a filter 80 is disposed in the space within the housing, which is sandwiched between the closing member 30 and the partition member 50 (i.e., the filter chamber S2). The filter 80 is a cylindrical member having a cavity 81 extending in a direction parallel to the axial direction of the housing body 10. One axial end face of the filter 80 abuts against the closing member 30, and the other axial end face of the filter 80 abuts against the partition wall portion 51 of the partition member 50.

[0059] 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. By using the filter 80 made of a cylindrical member as described above, 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.

[0060] The filter 80 can be preferably made of an aggregate of metal wire or metal mesh material made of stainless steel, iron, etc. Specifically, a knitted wire mesh, a plain woven wire mesh, an aggregate of crimped metal wire, or a combination of these compressed by a press can be used.

[0061] 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 a metal plate with staggered cuts that are then expanded to form holes and processed into a mesh-like structure, and hook metal, which is a metal plate with holes drilled in it and burrs that form around the holes are flattened by crushing them.

[0062] The housing body 10 in the portion defining the filter chamber S2 is provided with a plurality of gas outlets 14 arranged in the circumferential and axial directions. These gas outlets 14 are for directing the gas that has passed through the filter 80 to the outside of the housing.

[0063] Next, with reference to FIG. 1, an operation during operation of cylinder-shaped gas generator 1A according to the present embodiment will be described.

[0064] Referring to FIG. 1, when a vehicle equipped with cylinder-shaped gas generator 1A according to this embodiment collides, the collision is detected by collision detection means provided separately in the vehicle, and based on this, igniter 40 is activated by current supplied from a control unit provided separately in the vehicle.

[0065] When the igniter 40 is activated, the pressure inside the ignition section 42 increases due to the combustion of the ignition charge and / or the transfer charge in addition to the ignition charge, which causes the squib cup of the ignition section 42 to split, and thermal particles generated by the combustion of the ignition charge and / or the transfer charge in addition to the ignition charge flow out to the outside of the ignition section 42. The thermal particles that reach the gas generating agent 60 combust the gas generating agent 60, thereby generating a large amount of gas inside the combustion chamber S1.

[0066] As a result, the pressure in the combustion chamber S1 rises, and when the internal pressure of the combustion chamber S1 reaches a predetermined pressure, a fracture occurs in the portion of the partition member 50 where the score 51a 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 combustion chamber S1 and the filter chamber S2 are in communication with each other via the opening.

[0067] As a result, gas generated in the combustion 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 axially through the hollow portion 81 of the filter 80, then changes direction in the radial direction and flows through the interior of the filter 80. During this process, the filter 80 removes heat, cooling the gas, and also removes slag contained in the gas.

[0068] The gas that has passed through filter 80 is then ejected to the outside of the housing via gas ejection port 14 provided in housing main body 10. The ejected gas is introduced into the inside of an airbag provided adjacent to cylinder-shaped gas generator 1A, and inflates and deploys the airbag. Note that auto-ignition agent 61 burns together with gas generating agent 60 when it is burned.

[0069] Figures 4(A) and 4(B) are perspective views of a second holder of the holder assembly included in the cylinder-shaped gas generator according to this embodiment. Figures 5(A) and 5(B) are plan and bottom views, respectively, of the second holder, and Figure 5(C) is a cross-sectional view taken along line VC-VC shown in Figures 5(A) and 5(B). Figures 6(A) to 6(C) are schematic cross-sectional views showing, in stages, the procedure for assembling the holder assembly in the cylinder-shaped gas generator according to this embodiment and the procedure for assembling the holder assembly to the housing main body. Figure 7 is a cross-sectional view taken along line VII-VII shown in Figure 2, and Figures 8(A) and 8(B) are enlarged cross-sectional views of essential portions taken along lines VIIIA-VIIIA and VIIIB-VIIIB, respectively, shown in Figure 7. Next, with reference to FIGS. 4(A) to 8(B) and the above-mentioned FIG. 2, a detailed structure in the vicinity of igniter 40 in cylinder-shaped gas generator 1A according to the present embodiment will be described.

[0070] 2 , in cylinder-shaped gas generator 1A according to the present embodiment, as described above, igniter 40 is supported by holder assembly 20 that is assembled to housing main body 10 so as to close the one axial end of the housing, thereby assembling igniter 40 to the one axial end of the housing. Holder assembly 20 includes first holder 20A made of metal, second holder 20B made of resin, and third holder 20C made of resin, and holder assembly 20 is fixed to housing main body 10 by first crimping portion 11 and second crimping portion 12 that are provided at predetermined positions on housing main body 10.

[0071] As shown in Figure 2, the first holder 20A is composed of a flat, approximately disk-shaped member having a through portion extending axially in its center, and includes a cylindrical first body portion 21 and an annular protrusion 22 protruding outward from the outer peripheral surface of the first body portion 21.

[0072] The first holder 20A is inserted into the housing body 10 so that its axial direction is parallel to the axial direction of the housing body 10. As a result, the through-hole provided in the first holder 20A defines part of the hollow portion described above of the holder assembly 20, and the annular protrusion 22 protrudes outward from the first body 21 along the radial direction of the housing body 10. The annular protrusion 22 described above is provided at the end of the first body 21 on the combustion chamber S1 side.

[0073] First holder 20A is a member for receiving and holding igniter 40, and has a concave first housing portion 21a at its axial end on the combustion chamber S1 side to receive igniter 40. This first housing portion 21a communicates with a through-hole provided in first holder 20A and defines part of the hollow portion described above of holder assembly 20. In addition, a crimping portion 21b is provided at the end on the combustion chamber S1 side of first holder 20A so as to surround first housing portion 21a. Crimping portion 21b is a portion for crimping and fixing igniter 40 to first holder 20A.

[0074] Igniter 40 is fixed to first holder 20A with its base 41 accommodated in first housing portion 21a of first holder 20A. Specifically, base 41 is inserted into first housing portion 21a of first holder 20A, and base 41 is fastened against the bottom surface of first housing portion 21a. In this state, crimping portion 21b provided on first holder 20A is bent, thereby fixing igniter 40 to first holder 20A. In this way, igniter 40 is held by first holder 20A.

[0075] Here, the sealing member 28, which is made of the above-mentioned O-ring or the like, is interposed between the first holder 20A and the igniter 40. Specifically, the sealing member 28 is disposed on the outer edge of the bottom surface of the first housing portion 21a of the first holder 20A. As a result, the sealing member 28 is sandwiched and compressed between the first holder 20A and the igniter 40 by the pressing force generated by the above-mentioned crimping portion 21b being crimped, thereby sealing the gap that occurs between the holder assembly 20 and the igniter 40.

[0076] As shown in Figures 2 and 4(A) to 5(C), the second holder 20B is composed of a substantially cylindrical member having a second accommodating portion 23a in the form of a generally through-hole extending along the axial direction in its center, and includes a cylindrical second body portion 23 and a lid portion 26 provided to cover one axial end of the second accommodating portion 23a.

[0077] The second holder 20B is disposed on the combustion chamber S1 side as viewed from the first holder 20A, and is positioned adjacent to the first holder 20A. The second holder 20B is inserted into the housing body 10 so that its axial direction is parallel to the axial direction of the housing body 10. As a result, the second accommodating portion 23a provided in the second holder 20B defines a part of the hollow portion of the holder assembly 20.

[0078] Second housing portion 23a provided in second holder 20B 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 as a result, the portion of second body portion 23 of second holder 20B closer to first holder 20A is positioned so as to surround the peripheral surface of ignition portion 42.

[0079] The above-mentioned lid portion 26 is provided at the axial end of the second body 23 opposite the first holder 20A side so as to be positioned a predetermined distance away from the ignition portion 42. Here, the second body 23 extends along the axial direction of the housing main body 10 so as to be positioned protruding further toward the combustion chamber S1 than the ignition portion 42, and by providing the lid portion 26 at the axial end on the tip side of the second body 23, the lid portion 26 is positioned a predetermined distance away from the ignition portion 42.

[0080] The lid portion 26 is provided with a plurality of openings 26a, and the maximum outer dimension of each of these plurality of openings 26a when viewed along the axial direction of the housing main body 10 is configured to be smaller than the minimum outer dimension of the gas generating agent 60. More specifically, in this embodiment, one circular opening 26a is provided in the center of the lid portion 26, and three openings 26a in the shape of curved elongated holes are provided to surround it, so that the maximum outer dimension of each opening 26a is configured to be smaller than the minimum outer dimension of the gas generating agent 60.

[0081] As a result, the second storage section 23a, which is located on the opposite side of the base 41 from the ignition section 42, is essentially closed by the lid section 26 at a position a predetermined distance away from the ignition section 42, preventing the gas generating agent 60 from entering the second storage section 23a and separating the gas generating agent 60 so that it is positioned at a distance from the ignition section 42.

[0082] In this way, the second holder 20B functions as a directional member that fills the gap between the ignition portion 42 of the igniter 40 and the housing main body 10, thereby imparting directionality to the direction of travel of the thermal particles generated in the ignition portion 42 when the cylinder-shaped gas generator 1A is activated, and in particular, the second body portion 23 of the second holder 20B has this function.

[0083] In addition, the second holder 20B also functions as a spacer to maintain the distance between the ignition portion 42 and the gas generating agent 60 at a predetermined appropriate distance, and in particular, the lid portion 26 of the second holder 20B has this function.

[0084] Here, a first annular step portion 23b is provided at the axial end portion of the second holder 20B located on the first holder 20A side, the first annular step portion 23b being formed by cutting out a part of the second body portion 23. This first annular step portion 23b is provided on the inner edge of the end portion of the second body portion 23 on the first holder 20A side. The crimping portion 21b of the first holder 20A is fitted into this first annular step portion 23b provided on the second holder 20B.

[0085] As shown in Figure 2, the third holder 20C is composed of a substantially cylindrical member having a third accommodating portion 27a in the form of a through hole extending along the axial direction in its center, and includes a cylindrical third body portion 27.

[0086] The third holder 20C is disposed on the opposite side of the combustion chamber S1 from the first holder 20A, and is positioned adjacent to the first holder 20A. The third holder 20C is inserted into the housing body 10 so that its axial direction is parallel to the axial direction of the housing body 10. As a result, the third accommodating portion 27a provided in the third holder 20C defines a part of the hollow portion of the holder assembly 20.

[0087] Third housing portion 27a provided in third holder 20C houses a pair of terminal pins 43 of igniter 40. That is, third holder 20C is positioned so as to surround the pair of terminal pins 43 of igniter 40 held by first holder 20A, and thus the pair of terminal pins 43 of igniter 40 are disposed inside third holder 20C. Third housing portion 27a constitutes a portion for receiving the connector for connecting the harness described above.

[0088] More specifically, as described above, in cylinder-shaped gas generator 1A, igniter 40 must be electrically connected to an externally provided control unit of a vehicle or the like, and a harness is normally used for this electrical connection. A male connector is attached to the tip of this harness, and third holder 20C must be provided with a female connector that can be connected to this male connector. Third housing portion 27a provided in third holder 20C constitutes this female connector.

[0089] Incidentally, when the male connector of the harness is inserted into the third housing portion 27a, which functions as a female connector, electrical continuity is established between the core wire of the harness and the terminal pin 43. This allows the igniter 40 to be connected to a control unit of the vehicle or the like.

[0090] Here, a second annular step portion 27b is provided at the axial end portion of the third holder 20C located on the first holder 20A side by cutting out a part of the third body portion 27. This second annular step portion 27b is provided on the inner edge of the end portion of the third body portion 27 located on the first holder 20A side. The axial end portion of the first body portion 21 of the first holder 20A on the opposite side to the combustion chamber S1 side is fitted into this second annular step portion 27b provided on the third holder 20C.

[0091] The materials for the second holder 20B and the third holder 20C described above are 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 type of material or different types of materials.

[0092] With the above-described configuration, in cylinder-shaped gas generator 1A according to the present embodiment, second holder 20B can be provided with a function as a directionality imparting member, as described above. That is, by substantially filling the gap between ignition portion 42 and housing main body 10 with second holder 20B, the degree of opening of the squib cup during operation of cylinder-shaped gas generator 1A is intentionally limited, and an opening is formed mainly at the tip portion of the squib cup located on the gas generating agent 60 side, and accordingly the traveling direction of thermal particles generated at ignition portion 42 is narrowed to the axial direction of housing main body 10. Therefore, it becomes possible to efficiently guide the thermal particles generated at ignition portion 42 to gas generating agent 60, and it becomes possible to reduce the amount of gas generating agent 60 charged that is required to obtain a desired gas output.

[0093] Furthermore, by substantially filling the gap between ignition portion 42 and housing main body 10 with second holder 20B, it is possible to reduce the volume of combustion chamber S1 compared to when this portion is not filled, and this promotes an increase in the internal pressure of combustion chamber S1 when cylinder-shaped gas generator 1A is activated. Therefore, also in this respect, it is possible to burn gas generating agent 60 efficiently, and it is possible to reduce the amount of gas generating agent 60 charged that is required to obtain the desired gas output.

[0094] Furthermore, with the above-described configuration, in cylinder-shaped gas generator 1A according to the present embodiment, as described above, by providing lid portion 26 on second holder 20B, second holder 20B is provided with the function of a spacer for maintaining a predetermined appropriate distance between ignition portion 42 and gas generating agent 60. Therefore, with this configuration, individual differences in the distance between igniter 40 and gas generating agent 60 are unlikely to occur, and it becomes possible to stably obtain the desired gas output when cylinder-shaped gas generator 1A is activated.

[0095] As shown in Figures 6(A) to 6(C), when assembling the igniter 40 to the above-mentioned one axial end of the housing main body 10, the holder assembly 20 and the igniter 40 are first assembled to form a sub-assembly of the holder assembly 20 and the igniter 40, and then this sub-assembled holder assembly 20 and igniter 40 (hereinafter referred to as the igniter assembly) is assembled to the housing main body 10.

[0096] Specifically, as shown in Figure 6 (A), a first holder 20A is prepared to which an igniter 40 and a sealing member 28 are pre-assembled, and the second holder 20B and the third holder 20C are assembled to the first holder 20A to produce the igniter assembly.

[0097] The second holder 20B is assembled to the first holder 20A in the direction of arrow DR1 in the figure so that the ignition part 42 is accommodated in the second accommodation part 23a. At this time, the crimping part 21b of the first holder 20A is fitted into the first annular step part 23b of the second holder 20B, and the ignition part 42 is press-fitted into the second body part 23 of the second holder 20B. The press-fitting of the ignition part 42 into the second body part 23 will be described in detail later. This fixes the second holder 20B to the first holder 20A.

[0098] The third holder 20C is assembled to the first holder 20A in the direction of arrow DR2 in the figure so that the pair of terminal pins 43 are accommodated in the third accommodating portion 27a. At this time, the axial end of the first holder 20A is fitted and press-fit into the second annular stepped portion 27b provided on the third holder 20C. This fixes the third holder 20C to the first holder 20A.

[0099] 6(B), the igniter assembly produced by assembling first holder 20A, second holder 20B, third holder 20C, igniter 40, and seal member 28 is inserted and press-fit into the above-mentioned one axial end of housing body 10 in the direction of arrow DR3 in the figure. As a result, the outer peripheral surfaces corresponding to the maximum outer diameter portions of first holder 20A, second holder 20B, and third holder 20C come into pressure contact with the inner peripheral surface of housing body 10, and the igniter assembly inserted into housing body 10 is positioned and disposed at a predetermined position inside housing body 10, so that the igniter assembly is held by housing body 10 at that predetermined position.

[0100] Next, as shown in FIG. 6C, the housing body 10 is reduced in diameter inward in the radial direction at a predetermined position, whereby the igniter assembly is fixed to the housing body 10 by crimping.

[0101] Specifically, the housing body 10 is reduced in diameter in the direction of arrow A at a position of the second holder 20B corresponding to the portion adjacent to the first holder 20A, and is reduced in diameter in the direction of arrow B at a position of the third holder 20C corresponding to the portion adjacent to the first holder 20A. The reduction of the diameter of the housing body 10 at these two locations is performed by the above-mentioned eight-way crimping method, and is performed simultaneously using a dedicated crimping machine.

[0102] 2, the annular protrusion 22 of the first holder 20A is sandwiched in the axial direction of the housing body 10 by the housing body 10 which has been reduced in diameter at the two locations. That is, the annular protrusion 22 is immovably sandwiched between the first crimping portion 11 and the second crimping portion 12, which are the two locations of the housing body 10 which have been reduced in diameter, and the igniter assembly including the holder assembly 20 is thereby crimped and fixed to the housing body 10.

[0103] 2, the first crimping portion 11 is reduced in diameter so that its inner peripheral surface is in pressure contact with the outer peripheral surface of the second body 23 of the second holder 20B, and the second crimping portion 12 is reduced in diameter so that its inner peripheral surface is in pressure contact with the outer peripheral surface of the third body 27 of the third holder 20C. This brings the first crimping portion 11 and the second holder 20B into close contact with each other, and also brings the second crimping portion 12 and the third holder 20C into close contact with each other, preventing a gap from occurring between the housing main body 10 and the holder assembly 20, thereby sealing the gap. Note that if the sealing performance is insufficient through this crimping alone, sealing performance may be ensured by applying a liquid sealant between the housing main body 10 and the holder assembly 20, for example.

[0104] As described above, when assembling the second holder 20B to the first holder 20A, not only is the crimped portion 21b of the first holder 20A fitted into the first annular step portion 23b provided on the second holder 20B, but the ignition portion 42 is press-fitted into the second body portion 23 of the second holder 20B. This is because it is difficult to press-fit the crimped portion 21b into the first annular step portion 23b due to the shape and size of the crimped portion 21b. Furthermore, if the second holder 20B is not sufficiently fixed to the first holder 20A, there is a possibility that the second holder 20B will become misaligned when the igniter assembly is later crimped and fixed to the housing main body 10 as described above.

[0105] However, when press-fitting ignition portion 42 into second barrel portion 23, it is necessary to suppress as much as possible deformation of ignition portion 42 (i.e., deformation of the squib cup) due to the press-fitting. This is because, if ignition portion 42 is significantly deformed by the press-fitting, this deformation may have a significant effect on the combustion performance of the ignition charge during activation, which in turn may have an adverse effect on the output characteristics of cylinder-shaped gas generator 1A.

[0106] In addition, when the igniter assembly is crimped to the housing body 10, the housing body 10 is reduced in diameter so that the inner circumferential surface of the housing body 10 where the first crimping portion 11 is formed comes into pressure contact with the outer circumferential surface of the second body portion 23 of the second holder 20B, and a compressive force is also applied locally to the second body portion 23 at that portion. As a result, a compressive force also acts on the igniter portion 42 via the second body portion 23, and there is a risk that this compressive force will cause the igniter portion 42 to deform significantly. Therefore, when the igniter assembly is crimped to the housing body 10, it is necessary to suppress deformation of the igniter portion 42 as much as possible.

[0107] In this regard, in cylinder-shaped gas generator 1A according to the present embodiment, it is possible to minimize deformation of ignition portion 42 while press-fitting ignition portion 42 into second barrel portion 23, and it is also possible to minimize deformation of ignition portion 42 when the igniter assembly is crimped and fixed to housing body 10. The mechanism behind this is described in detail below.

[0108] 4(A) to 5(C), in cylinder-shaped gas generator 1A according to the present embodiment, second body portion 23 of second holder 20B has a plurality of protrusions 24 provided on the inner circumferential surface of a portion 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 (i.e., the axial direction of housing body 10 in the assembled state), these plurality of protrusions 24 are positioned in a dotted row along the circumferential direction of second body portion 23 and protrude toward ignition portion 42.

[0109] Here, as shown in Figures 2 and 7, the inner diameter of the second holder 20B (i.e., the diameter of the second accommodating portion 23a) is configured to be slightly larger than the diameter of the ignition portion 42, and the protrusion amounts of the multiple protrusions 24 are adjusted so that when the ignition portion 42 is inserted into the second body portion 23 of the second holder 20B, their tips come into pressure contact with the outer peripheral surface of the ignition portion 42 with a relatively weak force.

[0110] Therefore, when and after the ignition portion 42 is pressed into the second body portion 23, only the multiple protrusions 24 come into contact with the outer peripheral surface of the ignition portion 42, and in areas other than the areas where these protrusions 24 are provided, a gap (the area indicated by symbol G in Figures 7, 8(A), and 8(B), which show the state after the press-fitting) is formed between the outer peripheral surface of the ignition portion 42 and the inner peripheral surface of the second body portion 23.

[0111] Therefore, with this configuration, during and after press-fitting of ignition part 42 into second body part 23, most of the area where ignition part 42 and second body part 23 face each other is separated by gap G (i.e., there is no direct contact), 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.

[0112] 7, 8(A), and 8(B), even when the igniter assembly is crimped to the housing body 10, only the tips of the multiple protrusions 24 are in pressure contact with the igniter portion 42 with a relatively weak force, and therefore most of the compressive force applied to the second trunk portion 23 when the diameter of the housing body 10 is reduced is not transmitted to the igniter portion 42 due to the provision of the gap G, but is transmitted to the igniter portion 42 only at the portion in contact with the multiple protrusions 24. Therefore, even when the igniter assembly is crimped to the housing body 10, deformation of the igniter portion 42 can be suppressed.

[0113] Here, it is preferable that the multiple protrusions 24 are arranged so as not to sandwich the axis of the ignition part 42 in a direction perpendicular to the axis. With this configuration, the multiple protrusions 24 come into pressure contact with the ignition part 42, causing the directions of the forces applied to the ignition part 42 to intersect with each other (in other words, these forces can be prevented from overlapping in opposite directions on the same straight line), making it possible to more reliably suppress deformation of the ignition part 42.

[0114] Furthermore, it is preferable that the plurality of protrusions 24 are evenly spaced along the circumferential direction of the second body portion 23. This configuration makes it possible to distribute the force applied to the ignition portion 42, thereby more reliably suppressing deformation of the ignition portion 42.

[0115] Based on these points of view, it is most preferable that the multiple protrusions 24 are provided in an odd number evenly spaced along the circumferential direction of the second body portion 23, and in this embodiment, three of these multiple protrusions 24 are provided evenly along the circumferential direction of the second body portion 23.

[0116] 2 and 4(A) to 8(B), in cylinder-shaped gas generator 1A according to the present embodiment, groove portion 25 is provided around second barrel portion 23 at a position radially outward from a portion of second barrel portion 23 of second holder 20B where multiple projections 24 are provided. Groove portion 25 is provided on the axial end face of second barrel portion 23 on the first holder 20A side.

[0117] This configuration significantly reduces the rigidity of the portion of second body 23 where multiple protrusions 24 are provided, thereby reducing the force applied to ignition part 42 by multiple protrusions 24 when and after ignition part 42 is press-fitted into second body 23. Therefore, deformation of ignition part 42 can be more reliably suppressed while ignition part 42 is press-fitted into second body 23.

[0118] Furthermore, with this configuration, even when the igniter assembly is crimped to the housing body 10, the compressive force applied to the second body portion 23 as the diameter of the housing body 10 is reduced is effectively absorbed by the second body portion 23 due to the provision of the groove portion 25. Therefore, even when the igniter assembly is crimped to the housing body 10, deformation of the ignition portion 42 can be more reliably suppressed.

[0119] As described above, by using cylinder-shaped gas generator 1A according to this embodiment, it is possible to firmly fix second holder 20B to first holder 20A by press-fitting ignition portion 42 into second body portion 23 while suppressing deformation of ignition portion 42, and by providing first crimping portion 11 and second crimping portion 12 on housing main body 10, it is possible to firmly fix the igniter assembly including first holder 20A, second holder 20B, third holder 20C, igniter 40, etc. to housing main body 10.

[0120] Therefore, by employing the above configuration, it is possible to stably fix holder assembly 20 including second holder 20B that functions as a directionality imparting member, and further, igniter assembly including holder assembly 20, so that they cannot move relative to the housing. Therefore, it is possible to prevent second holder 20B, which functions as a directionality imparting member, from shifting position inside housing main body 10, making it less likely that individual differences will occur in the distance between igniter 40 and gas generating agent 60, and making it possible to provide a cylinder-type gas generator that can stably obtain the desired gas output.

[0121] Furthermore, when this configuration is adopted, it becomes possible to equip cylinder-shaped gas generator 1A with second holder 20B that functions as a directional member with a relatively simple configuration, and since this can be assembled through relatively easy assembly work such as press-fitting or crimping, it is also possible to suppress increases in manufacturing costs.

[0122] Therefore, cylinder-shaped gas generator 1A according to the present embodiment can be a cylinder-shaped gas generator that can stably obtain a desired gas output while suppressing increases in manufacturing costs.

[0123] Additionally, in cylinder-shaped gas generator 1A according to the present embodiment, as described above, lid portion 26 is provided on second holder 20B, thereby making it less likely that individual differences will occur in the distance between igniter 40 and gas generating agent 60. Therefore, in this respect as well, a cylinder-shaped gas generator can be provided that can stably obtain the desired gas output.

[0124] Here, in cylinder-shaped gas generator 1A according to the present embodiment, by employing the above configuration, the portion of housing body 10 where first crimping portion 11 is provided has a shape that is curved in the axial direction of housing body 10, unlike the portion of housing body 10 that defines combustion chamber S1. Therefore, the portion of housing body 10 where first crimping portion 11 is provided has inferior strength compared to the portion of housing body 10 that defines combustion chamber S1.

[0125] However, in cylinder-shaped gas generator 1A according to the present embodiment, the inner circumferential surface of first crimped portion 11 is substantially covered by second body portion 23 of second holder 20B, and therefore, during operation of cylinder-shaped gas generator 1A, second body portion 23 of second holder 20B protects first crimped portion 11. Therefore, the pressure resistance performance of cylinder-shaped gas generator 1A as a whole is also improved.

[0126] (Embodiment 2) Fig. 9 is an enlarged cross-sectional view of the vicinity of the igniter of a cylinder-shaped gas generator according to Embodiment 2. Hereinafter, with reference to Fig. 9, a cylinder-shaped gas generator 1B according to the present embodiment will be described.

[0127] As shown in Figure 9, cylinder-shaped gas generator 1B according to the present embodiment differs in configuration from cylinder-shaped gas generator 1A according to the first embodiment described above only in that ignition portion 42 is not press-fit into second body portion 23 of second holder 20B, but the other configurations are similar to cylinder-shaped gas generator 1A described above.

[0128] Therefore, even when configured in this manner, all of the effects described in the above-mentioned first embodiment can be obtained except for the effect obtained by pressing the ignition portion 42 into the second body portion 23 of the second holder 20B, and therefore it is possible to provide a cylinder-shaped gas generator that can stably obtain the desired gas output while suppressing increases in manufacturing costs.

[0129] (Summary of First and Second Embodiments) The characteristic configurations of the gas generators disclosed in the first and second embodiments described above can be summarized as follows.

[0130] [Supplementary Note 1] A housing assembly comprising: a cylindrical metal housing body including a combustion chamber therein in which a gas generating agent is accommodated; a holder assembly inserted into an axial opening end of the housing body and including a hollow portion extending along a direction parallel to the axial direction of the housing body; and an igniter including an ignition portion loaded with an ignition charge, a terminal pin connected to the ignition portion, and a base portion through which the terminal pin is inserted and which supports both the ignition portion and the terminal pin, at least a portion of which is disposed inside the hollow portion with the ignition portion located on the combustion chamber side and the terminal pin located on the opposite side to the combustion chamber side, the holder assembly having a metal first holder that receives the base to hold the igniter, and a resin second holder that is located on the combustion chamber side as viewed from the first holder and accommodates the ignition portion, the first holder including a cylindrical first barrel portion that defines the hollow portion and an annular protrusion that protrudes from the first barrel portion along a radial direction of the housing body, the second holder includes a cylindrical second body portion that defines the hollow portion; the housing main body has a first crimped portion that tapers radially inward, and a second crimped portion that is located on the opening end side as viewed from the first crimped portion and tapers radially inward; the first holder is fixed to the housing main body by sandwiching the annular protrusion between the first crimped portion and the second crimped portion in the axial direction of the housing main body; the first crimped portion is covered by the second body portion and is in pressure contact with at least a portion of an outer circumferential surface of the second body portion; the second holder further has a lid portion that separates the gas generating agent from the ignition portion by closing at least a portion of the hollow portion located on the opposite side to the base side as viewed from the ignition portion; and the lid portion is arranged at a distance from the ignition portion along the axial direction of the housing main body.

[0131] [Appendix 2] The gas generator according to Appendix 1, wherein a plurality of openings are provided in the lid portion, and a maximum outer dimension of each of the plurality of openings when viewed along the axial direction of the housing body is smaller than a minimum outer dimension of the gas generating agent.

[0132] [Supplementary Note 3] The gas generator according to Supplementary Note 1 or 2, wherein the lid portion is provided at an axial end portion of the second body portion that is located opposite to an axial end portion on the first holder side.

[0133] [Appendix 4] A gas generator according to any one of Appendices 1 to 3, wherein an axial end of the second holder located on the first holder side is fitted into the first holder and thereby fixed to the first holder.

[0134] [Supplementary Note 5] A gas generator as set forth in any of Supplementary Notes 1 to 4, wherein the holder assembly further has a third holder made of resin, located on the opposite side of the combustion chamber as seen from the first holder, and capable of receiving a connection connector to be connected to the terminal pin, the third holder including a cylindrical third body portion that defines the hollow portion, and the second crimping portion is in pressure contact with at least a part of the outer peripheral surface of the third body portion.

[0135] [Supplementary Note 6] The gas generator according to Supplementary Note 5, wherein an axial end of the third holder located on the first holder side is fitted into the first holder and thereby fixed to the first holder.

[0136] (Other Embodiments, etc.) In the above-described first and second embodiments of the present invention, the holder assembly is configured with a metal first holder that primarily functions to hold an igniter, a resin second holder that primarily functions as a directionality imparting member, and a resin third holder that primarily constitutes a female connector portion. However, a single member may be used as both the first holder and the third holder. In that case, the single member may be made of metal, have the function of holding an igniter, and be provided with a female connector portion.

[0137] Furthermore, in the above-described first and second embodiments of the present invention, the case where a plurality of openings are provided in the lid portion of the second holder has been described as an example, but a single opening may be provided in the lid portion. Furthermore, if the lid portion itself is configured to be thin and fragile, or if scores are provided in the lid portion so that it opens due to the combustion of the ignition charge when the cylinder-shaped gas generator is activated, it is not necessarily necessary to provide an opening in the lid portion.

[0138] Furthermore, the shape, size, number, placement position, etc. of each component disclosed in the above-described first and second embodiments of the present invention can naturally be modified in various ways within the scope that does not deviate from the spirit of the present invention.

[0139] Furthermore, in the above-mentioned first and second embodiments of the present invention, the case where the present invention is applied to a cylinder-type gas generator incorporated in a side airbag device has been described as an example, but the application of the present invention is not limited to this, and the present invention can also be applied to a cylinder-type gas generator incorporated in a curtain airbag device, a knee airbag device, a seat cushion airbag device, etc., and a so-called T-shaped gas generator which has an elongated outer shape like a cylinder-type gas generator.

[0140] As such, the above-described embodiments disclosed herein are illustrative in all respects and are not restrictive. The technical scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope of the claims.

[0141] DESCRIPTION OF SYMBOLS 1A, 1B Cylinder-shaped gas generator, 10 Housing body, 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 accommodating portion, 21b Crimped portion, 22 Annular protrusion, 23 Second body portion, 23a Second accommodating portion, 23b First annular stepped portion, 24 Protrusion portion, 25 Groove portion, 26 Lid portion, 26a Opening portion, 27 Third body portion, 27a Third accommodating portion, 27b Second annular stepped portion, 28 Sealing member, 30 Closing member, 40 Igniter, 41 Base portion, 42 Ignition portion, 43 Terminal pin, 50 Partition member, 51 Partition wall portion, 51a Score, 52 annular wall portion, 60 gas generating agent, 61 auto-ignition agent, 70 coil spring, 71 spring portion, 72 pressing portion, 80 filter, 81 cavity portion, 90 welded portion, G gap portion, S1 combustion chamber, S2 filter chamber.

Claims

1. A housing assembly comprising: a cylindrical metal housing body including a combustion chamber containing a gas generating agent; a holder assembly inserted into the axial opening end of the housing body and including a hollow portion extending parallel to the axial direction of the housing body; and an igniter including an ignition part loaded with an ignition charge, a terminal pin connected to the ignition part, and a base through which the terminal pin is inserted and which supports both the ignition part and the terminal pin, with at least a portion of the ignition part positioned inside the hollow portion with the ignition part positioned on the combustion chamber side and the terminal pin positioned on the opposite side to the combustion chamber side, the holder assembly having a metal first holder which receives the base to hold the igniter, and a resin second holder which is positioned on the combustion chamber side as viewed from the first holder and contains the ignition part, the first holder including a cylindrical first body portion which defines the hollow portion, and an annular protrusion protruding from the first body portion along the radial direction of the housing body, a second holder including a cylindrical second body portion defining the hollow portion, the housing body having a first crimped portion tapering radially inward and a second crimped portion located on the opening end side as viewed from the first crimped portion and tapering radially inward, the first holder being fixed to the housing body by the first crimped portion and the second crimped portion clamping the annular protrusion in the axial direction of the housing body, the first crimped portion being covered by the second body portion and being in pressure contact with at least a portion of an outer circumferential surface of the second body, the second holder further having a lid portion separating the gas generating agent from the ignition portion by closing at least a portion of the hollow portion located on the opposite side to the base side as viewed from the ignition portion, and the lid portion being disposed at a distance from the ignition portion along the axial direction of the housing body.

2. A gas generator as set forth in claim 1, wherein a plurality of openings are provided in said cover portion, and the maximum outer dimension of each of said plurality of openings when viewed along the axial direction of said housing body is smaller than the minimum outer dimension of said gas generating agent.

3. A gas generator as set forth in claim 1, wherein the cover portion is provided at an axial end portion of the second body portion that is located opposite to the axial end portion on the first holder side.

4. A gas generator as set forth in claim 1, wherein an axial end portion of said second holder located on the side of said first holder is fitted into said first holder and thereby fixed to said first holder.

5. A gas generator as described in claim 1, wherein the holder assembly further includes a third holder made of resin, located on the opposite side of the combustion chamber as viewed from the first holder and capable of receiving a connecting connector to be connected to the terminal pin, the third holder includes a cylindrical third body portion defining the hollow portion, and the second crimping portion is in pressure contact with at least a portion of the outer circumferential surface of the third body portion.

6. A gas generator according to claim 5, wherein an axial end of said third holder located on the side of said first holder is fitted into said first holder and thereby fixed to said first holder.

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