Gas generator

Abstract

To provide a gas generator which can stably obtain a desired gas output while inhibiting increase of manufacturing costs.SOLUTION: 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.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a gas generator to be incorporated in an airbag device as an occupant protection device equipped in an automobile or the like, and in particular to a so-called cylindrical gas generator having an elongated cylindrical outer shape which can be suitably incorporated in a side airbag device or the like. [Background technology]

[0002] Conventionally, airbag devices, which are passenger protection devices, have become widespread from the viewpoint of protecting passengers in automobiles, etc. Airbag devices are installed for the purpose of protecting passengers from impacts that occur when a vehicle or the like crashes, and the airbag instantly inflates and deploys when a vehicle or the like crashes, so that the airbag acts as a cushion to receive the body of the passenger.

[0003] The gas generator is a device incorporated into the airbag device. When a vehicle crashes, an igniter is ignited by electrical current from a control unit. The flame produced in the igniter burns a 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 the specifications of the installation position relative to the vehicle, output, etc. One of them is called a cylinder-type gas generator. The cylinder-type gas generator has a long 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 attached to one axial end of a housing, and a combustion chamber containing a 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 part that defines the filter chamber.

[0006] In a cylindrical 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 via the gas outlet.

[0007] Here, in a cylinder-type gas generator, since the igniter and the gas generating agent are arranged along the axial direction of the housing, if the gas generating agent is arranged in contact with or close to the ignition part, which is the part of the igniter where the ignition charge is loaded, there is a concern that when the ignition part is ruptured during activation, the gas generating agent in the part arranged in contact with or close to the ignition part may hinder the rupture of the ignition part. If the rupture of the ignition part is hindered, there is a risk that the propagation of the thermal particles (i.e., the flame) generated by the igniter to the gas generating agent may be delayed or the thermal particles may move in a biased direction, resulting in a problem of variation 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 in the combustion characteristics of the gas generating agent itself.

[0008] In order to avoid such problems, for example, in the cylinder-type gas generators disclosed in 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 side beyond the ignition portion, thereby ensuring the distance between the gas generating agent and the igniter.

[0009] Furthermore, in a cylindrical 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 may be installed around the igniter as a guide to give directionality to the direction of travel of the thermal particles generated in the ignition section. Usually, the directivity imparting member has a cylindrical shape that surrounds the ignition section, and is installed inside the housing so as to fill the gap between the peripheral wall of the housing and the ignition section.

[0010] Literature that discloses a specific configuration of a cylindrical gas generator equipped with such a directionality imparting member includes, for example, JP 2017-1588 A (Patent Document 3) and JP 2017-81343 A (Patent Document 4). [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Patent Publication No. 2021-195020 [Patent Document 2] JP 2022-144932 A [Patent Document 3] JP 2017-1588 A [Patent Document 4] JP 2017-81343 A Summary of the Invention [Problem to be solved by the invention]

[0012] However, when the configurations disclosed in the above 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 in various parts during assembly, and it is unavoidable that individual differences, although slight, occur in the distance between the igniter and the gas generating agent. Therefore, in order to more precisely manage the distance between the igniter and the gas generating agent, it is necessary to adopt an assembly structure other than the assembly structure using such a coil spring.

[0013] Furthermore, when considering the above-mentioned other assembly structure, if it is assumed that the cylindrical 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 agent, and therefore it will be necessary to stably fix the directionality imparting member inside the housing so as not to move, and it is essential to consider this point as well. Furthermore, when considering the above-mentioned other assembly structure, it is naturally preferable that the assembly structure is not complicated from the viewpoint 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 increases in manufacturing costs. [Means for solving the problem]

[0015] A gas generator according to the present invention includes a housing body, a holder assembly, and an igniter. The housing is made of a cylindrical metal member including a combustion chamber in which a gas generating agent is accommodated. The holder assembly is inserted into an axial opening end of the housing body and includes a hollow portion extending along a direction 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 which supports both the ignition portion and the terminal pin, and at least a part of the igniter 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 includes a first metal holder that receives the base to hold the igniter, and a second resin holder that is located on the combustion chamber side as viewed from the first holder and accommodates 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 tapered radially inward and a second crimped portion located on the opening end side as viewed from the first crimped portion and tapered radially inward, and 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 portion 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. Effect of the Invention

[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. [Brief description of the drawings]

[0017] [Figure 1] 1 is a schematic diagram of a cylinder-shaped gas generator according to a first embodiment. [Diagram 2] 2 is an enlarged cross-sectional view of the vicinity of an igniter of the cylinder-shaped gas generator shown in FIG. 1. [Diagram 3] 2 is an enlarged cross-sectional view of the vicinity of a partition member of the cylinder-shaped gas generator shown in FIG. 1. [Figure 4] FIG. 2 is a perspective view of a second holder shown in FIG. [Diagram 5] 2A to 2C are a plan view, a bottom view and a cross-sectional view of the second holder shown in FIG. [Figure 6] 2A to 2C are schematic cross-sectional views 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. [Figure 7] FIG. 2 is a cross-sectional view of the cylinder-shaped gas generator shown in FIG. [Figure 8] 2 is an enlarged cross-sectional view of a main portion of the cylinder-shaped gas generator shown in FIG. 1. [Figure 9] 11 is an enlarged cross-sectional view of the vicinity of an igniter of a cylinder-shaped gas generator according to a second embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The embodiment shown below illustrates a case where the present invention is applied to a cylinder-type gas generator incorporated in a side airbag device. In the embodiment shown below, the same or common parts are given the same reference numerals in the drawings, and the description thereof 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 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, the configuration of cylinder-shaped gas generator 1A according to the present embodiment will be described with reference to Figs. 1 to 3.

[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 a housing main body 10, a holder assembly 20, a closing member 30, and a 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 the igniter 40, gas generating agent 60, autoignition agent 61, coil spring 70, and filter 80, and also accommodate the above-mentioned partition member 50, which is also an internal component. Also, located inside the housing are a combustion chamber S1, which accommodates the gas generating agent 60, autoignition agent 61, and 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 directivity 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 constitutes the peripheral wall of the housing and is made of a long cylindrical member with openings formed 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 having a hollow portion extending along a direction parallel to the axial direction of the housing body 10. The blocking 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, stainless alloy, etc., 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 resistance 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 formed by the holder assembly 20.

[0028] The blocking member 30 is fixed to the housing body 10 so as to block the other axial opening end of the housing body 10. Specifically, the blocking member 30 is inserted into the other opening end of the housing body 10 so that one axial end face of the blocking member 30 is abutted against the filter 80, and a predetermined position of the housing body 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 housing body 10. As a result, the other axial end of the housing is constituted by the blocking member 30.

[0029] Here, these crimping fixations are called eight-way crimping, which reduces the diameter of the housing body 10 almost uniformly inward in the radial direction. By performing this eight-way crimping, the housing body 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 housing body 10 into direct contact with the holder assembly 20 and the blocking member 30, respectively, preventing the occurrence of gaps between them. The fixing 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 above-mentioned assembly structure, and other assembly structures may be adopted. Also, the housing main body 10 and the closing member 30 may not be separate bodies, but may be configured as one member having a bottomed cylindrical shape.

[0031] 1 and 2, the igniter 40 is mounted to the one end in the axial direction of the housing by being supported by the holder assembly 20. The igniter 40 is for combusting the gas generating agent 60, and is disposed so as to face the space inside 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 a control unit (not shown) of a vehicle or the like that is provided externally.

[0033] The ignition unit 42 includes 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, the ignition unit 42 includes a squib cup formed in a cup shape, the resistor is attached so as to connect the tips of a pair of terminal pins 43 inserted into the squib cup, and an ignition charge is loaded into the squib cup so as to surround the resistor or to be adjacent to the resistor. In addition, an ignition charge may be loaded into the ignition unit 42 as necessary.

[0035] Here, the resistor generally uses a nichrome wire or a resistance wire made of an alloy containing platinum and tungsten, and the ignition charge generally uses ZPP (zirconium potassium perchlorate), ZWPP (zirconium tungsten potassium perchlorate), lead tricinate, etc. Also, the transfer charge generally uses a composition made of a metal powder / oxidizer such as B / KNO3, B / NaNO3, Sr(NO3)2, etc., a composition made of titanium hydride / potassium perchlorate, a composition made of B / 5-aminotetrazole / potassium nitrate / molybdenum trioxide, etc.

[0036] When a collision is detected, a predetermined amount of current flows through the resistor via the terminal pin 43. When a predetermined amount of current flows through the resistor, Joule heat is generated in the resistor, and the ignition charge begins to burn. High-temperature particles generated by the combustion split open the squib cup that contains 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 as the resistor.

[0037] Ignition unit 42 of igniter 40 is positioned to protrude toward the combustion chamber S1 side beyond base unit 41, and a part of igniter 40 is disposed inside the above-mentioned hollow portion of holder assembly 20, and is fixed to holder assembly 20. As a result, ignition unit 42 of igniter 40 is positioned on the combustion chamber S1 side, and terminal pin 43 is positioned on the opposite side to 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 the holder assembly 20 and the igniter 40, whereby the gap between the holder assembly 20 and the igniter 40 is filled with the seal member 28, thereby sealing the gap. With this configuration, 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 that 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 plate-like 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] The partition wall portion 51 has a score 51a on a main surface thereof that contacts the filter 80. The score 51a is for allowing the partition wall portion 51 to break and form an opening in response to an increase in the internal pressure of the combustion chamber S1 due to combustion of the gas generating agent 60, and is formed, for example, of a plurality of grooves provided radially so as to intersect with each other. The score 51a is 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 body 10 and then joined to the housing body 10. More specifically, the partition member 50 is press-fitted into the housing body 10, and fixed to the housing body 10 by joining the annular wall portion 52 of the partition member 50 to the housing body 10 at or near the contact portion between them, such as by welding.

[0043] As a result, a weld 90 extending along the circumferential direction of the housing is provided in the portion of the housing corresponding to the portion into which the partition member 50 is inserted, and the gap between the housing main body 10 and the partition member 50 is filled by this weld 90. Therefore, 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 that case, 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 autoignition 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 autoignition 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 burned by thermal particles generated by the activation of the igniter 40. As the gas generating agent 60, it is preferable to use a non-azide gas generating agent, 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 of these. Specifically, for example, nitroguanidine, guanidine nitrate, cyanoguanidine, 5-aminotetrazole, or the like is preferably used.

[0049] Examples of the oxidizing agent include basic metal salts such as basic copper nitrate and basic copper carbonate, perchlorates such as ammonium perchlorate and potassium perchlorate, and nitrates containing a cation selected from alkali metals, alkaline earth metals, transition metals, and ammonia. Examples of the nitrates that are preferably used include sodium nitrate and potassium nitrate.

[0050] Examples of additives include binders, slag formers, and combustion control agents. As binders, for example, organic binders such as metal salts of carboxymethylcellulose and stearates, and inorganic binders such as synthetic hydrotalcite and acid clay can be suitably used. As slag formers, silicon nitride, silica, acid clay, etc. can be suitably used. As combustion control agents, metal oxides, ferrosilicon, activated carbon, graphite, etc. can be suitably used.

[0051] The shape of the molded body of the gas generating agent 60 may be granular, pellet-like, cylindrical, or other granular, or disk-like. In addition, 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) may also be used. These shapes are preferably selected appropriately according to the specifications of the airbag device in which the cylindrical gas generator 1A is incorporated, and it is preferable to select an optimal shape according to the specifications, such as a shape in which the gas generation rate changes over time when the gas generating agent 60 is burned. In addition to the shape of the gas generating agent 60, it is preferable to appropriately select the size and filling amount of the molded body taking into consideration the linear burning rate and pressure exponent of the 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 due to vibration or the like, and has a spring portion 71 formed by bending a metal wire and a pair of pressing portions 72 located on both ends of the spring portion 71.

[0053] The spring portion 71 is a generally cylindrical portion in which a metal wire is wound in a spiral shape. 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 in generally parallel relation with a predetermined interval, or by arranging the metal wires in a spiral relation with 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 in a compressed state by being sandwiched between the autoignition agent 61 and the gas generating agent 60. Therefore, the gas generating agent 60 is elastically biased toward the holder assembly 20 by the coil spring 70, which prevents the gas generating agent 60 from moving inside the combustion chamber S1. Therefore, by configuring in this way, it is possible to prevent the gas generating agent 60 made of a molded body from being crushed by vibration or the like.

[0055] In addition, when the coil spring 70 is assembled, the coil spring 70 is sandwiched between the auto-ignition agent 61 and the gas generating agent 60 and compressed, so that the dimensional variations of the various components housed inside the housing can be absorbed by the coil spring 70.

[0056] The autoignition agent 61 is made of pellets formed into a flattened, 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 portion 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] The autoignition agent 61 is an agent that ignites automatically without depending on the operation of the igniter 40. More specifically, the autoignition agent 61 spontaneously ignites at a temperature lower than that of the gas generating agent 60, and is intended to prevent abnormal operation of the cylinder-shaped gas generator 1A from being induced by heating from the outside in the unlikely event that a fire or the like occurs in a vehicle or the like equipped with an airbag device in which the cylinder-shaped gas generator 1A is incorporated.

[0058] 1 and 3, within the space inside the housing, a filter 80 is disposed in a space sandwiched between the blocking member 30 and the partition member 50 (i.e., 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 housing body 10, with one axial end face abutting against the blocking member 30 and the other axial end face abutting against the bulkhead 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 realize an efficient gas flow.

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

[0061] Also, a perforated metal sheet wound around the filter 80 can be used. In this case, the perforated metal sheet can be, for example, an expanded metal sheet made by cutting a metal sheet in a zigzag pattern and expanding the cuts to form holes and process it into a mesh-like shape, or a hook metal sheet made by drilling holes in a metal sheet and flattening the metal sheet by crushing burrs that are generated around the edges of the holes.

[0062] A portion of the housing body 10 that defines the filter chamber S2 is provided with a plurality of gas outlets 14 along 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 a cylinder-shaped gas generator 1A according to this embodiment collides, the collision is detected by a collision detection means provided separately in the vehicle, and based on this, igniter 40 is activated by the passage of electricity 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 or, in addition, the transfer charge, which causes the squib cup of the ignition section 42 to split, and the thermal particles generated by the combustion of the ignition charge or, in addition, the transfer 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, which generates 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 break 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 in 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] Accordingly, gas generated in the combustion chamber S1 flows into the filter chamber S2 through an opening formed in the partition member 50. The gas that flows into the filter chamber S2 flows along the axial direction in the hollow portion 81 of the filter 80, then changes direction toward the radial direction, and flows through the inside of the filter 80. At that time, the filter 80 removes heat and cools the gas, and the filter 80 removes slag contained in the gas.

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

[0069] Fig. 4(A) and Fig. 4(B) are perspective views of the second holder of the holder assembly included in the cylinder-shaped gas generator according to this embodiment. Fig. 5(A) and Fig. 5(B) are plan and bottom views of the second holder, respectively, and Fig. 5(C) is a cross-sectional view taken along the line VC-VC shown in Fig. 5(A) and Fig. 5(B). Fig. 6(A) to Fig. 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. Fig. 7 is a cross-sectional view taken along the line VII-VII shown in Fig. 2, and Fig. 8(A) and Fig. 8(B) are enlarged cross-sectional views of essential parts taken along the lines VIIIA-VIIIA and VIIIB-VIIIB shown in Fig. 7, respectively. Next, a detailed structure in the vicinity of igniter 40 in cylinder-shaped gas generator 1A according to this embodiment will be described with reference to Figs. 4(A) to 8(B) and the above-mentioned Fig. 2.

[0070] 2, in cylinder-shaped gas generator 1A according to the present embodiment, as described above, igniter 40 is supported by holder assembly 20 mounted to housing body 10 so as to close the one end in the axial direction of the housing, whereby igniter 40 is mounted to the one end in the axial direction 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 body 10 by first crimping portion 11 and second crimping portion 12 provided at predetermined positions of housing body 10.

[0071] As shown in FIG. 2, the first holder 20A is composed of a flat, approximately disk-shaped member having a through portion extending axially in the center thereof, 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 portion provided in the first holder 20A defines a part of the above-mentioned hollow portion 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 above-mentioned annular protrusion 22 is provided at the end of the first body 21 on the combustion chamber S1 side.

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

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

[0075] Here, the above-mentioned seal member 28 made of an O-ring or the like is interposed between the first holder 20A and the igniter 40. Specifically, the seal 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 seal 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, and thus the gap generated between the holder assembly 20 and the igniter 40 is sealed.

[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 above-mentioned 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 thus a 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 portion of the second body 23 opposite the first holder 20A side so as to be located a predetermined distance away from the ignition portion 42. Here, the second body 23 extends along the axial direction of the housing body 10 so as to be located protruding further toward the combustion chamber S1 side than the ignition portion 42, and by providing the lid portion 26 at the axial end portion on the tip side, the lid portion 26 is located 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 the plurality of openings 26a when viewed along the axial direction of the housing 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. As a result, 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, thereby 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 body 10, thereby imparting directionality to the direction of travel of 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] 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 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 on the first holder 20A side of the second body portion 23. The crimping portion 21b of the first holder 20A is fitted into the first annular step portion 23b provided on the second holder 20B.

[0085] As shown in FIG. 2, the third holder 20C is made of a substantially cylindrical member having a third accommodating portion 27a in the form of a through hole extending axially in the center thereof, and includes a cylindrical third body portion 27.

[0086] The third holder 20C is disposed on the opposite side of the combustion chamber S1 side as viewed 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 housing portion 27a provided in the third holder 20C defines a part of the above-mentioned hollow portion of the holder assembly 20.

[0087] The third housing portion 27a provided in the third holder 20C houses a pair of terminal pins 43 of the igniter 40. That is, the third holder 20C is positioned so as to surround the periphery of the pair of terminal pins 43 of the igniter 40 held by the first holder 20A, and thus the pair of terminal pins 43 of the igniter 40 are disposed inside the third holder 20C. The 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-type 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 end 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, by inserting the male connector of the harness into the third housing portion 27a functioning 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 a vehicle or the like.

[0090] Here, a second annular step portion 27b is provided at an axial end portion of the third holder 20C located on the first holder 20A side, the second annular step portion 27b being formed by cutting out a part of the third body portion 27. This second annular step portion 27b is provided on an inner edge of the end portion of the third body portion 27 on the first holder 20A side. An 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 the second annular step portion 27b provided on the third holder 20C.

[0091] The material of the second holder 20B and the third holder 20C described above is not particularly limited, but may be, for example, 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] By being configured as described above, 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, the gap between ignition portion 42 and housing main body 10 is substantially filled by second holder 20B, and therefore the degree of opening of the squib cup during operation of cylinder-shaped gas generator 1A is intentionally limited, so that an opening is mainly formed 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 in ignition portion 42 is narrowed to the axial direction of housing main body 10. Therefore, it becomes possible to efficiently guide thermal particles generated in ignition portion 42 to gas generating agent 60, and it becomes possible to reduce the amount of gas generating agent 60 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-type gas generator 1A is activated. Therefore, in this respect as well, it is possible to efficiently burn gas generating agent 60, and it is possible to reduce the amount of gas generating agent 60 required to obtain a desired gas output.

[0094] Furthermore, by being configured as described above, in cylinder-shaped gas generator 1A according to the present embodiment, as described above, by providing cover portion 26 on second holder 20B, second holder 20B is endowed with the function of a spacer for maintaining a predetermined appropriate distance between ignition portion 42 and gas generating agent 60. Therefore, by being configured in this manner, individual differences in the distance between igniter 40 and gas generating agent 60 are less likely 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 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 body 10.

[0096] Specifically, as shown in FIG. 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 the arrow DR1 in the figure so that the ignition unit 42 is accommodated in the second accommodation portion 23a. At this time, the crimping portion 21b of the first holder 20A is fitted into the first annular step portion 23b provided in the second holder 20B, and the ignition unit 42 is press-fitted into the second body portion 23 of the second holder 20B. The press-fitting of the ignition unit 42 into the second body portion 23 will be described in detail later. This causes the second holder 20B to be fixed to the first holder 20A.

[0098] The third holder 20C is assembled to the first holder 20A in the direction of the 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 pressed 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 the first holder 20A, the second holder 20B, the third holder 20C, the igniter 40, and the seal member 28 is inserted and pressed into the one end of the housing body 10 in the axial direction in the direction of the arrow DR3 in the figure. As a result, the outer peripheral surfaces corresponding to the maximum outer diameter portions of the first holder 20A, the second holder 20B, and the third holder 20C are brought into pressure contact with the inner peripheral surface of the housing body 10, and the igniter assembly inserted into the housing body 10 is positioned and disposed at a predetermined position inside the housing body 10, so that the igniter assembly is held by the housing body 10 at the predetermined position.

[0100] Next, as shown in FIG. 6(C), the housing body 10 is contracted radially inward 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 shown in the figure at a position corresponding to a portion of the second holder 20B adjacent to the first holder 20A, and is reduced in diameter in the direction of arrow B shown in the figure at a position corresponding to a portion of the third holder 20C adjacent to the first holder 20A. The reduction in diameter of the housing body 10 at these two positions is both the above-mentioned eight-way crimping type crimping, 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 with its diameter reduced at the two locations. That is, the annular protrusion 22 is immovably sandwiched by the first crimping portion 11 and the second crimping portion 12, which are the two locations of the housing body 10 with their diameter reduced, 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. As a result, the first crimping portion 11 and the second holder 20B are closely attached to each other, and the second crimping portion 12 and the third holder 20C are closely attached to each other, preventing a gap from being generated between the housing main body 10 and the holder assembly 20, thereby sealing the gap. If the sealing performance is insufficient only by this fixing by crimping, the sealing performance may be ensured by applying a liquid sealant between the housing main body 10 and the holder assembly 20, for example.

[0104] Here, as described above, when the second holder 20B is assembled 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. In addition, if the second holder 20B is not sufficiently fixed to the first holder 20A, there is a possibility that the second holder 20B will be displaced when the igniter assembly is crimped and fixed to the housing main body 10 described above, which is performed later.

[0105] However, when press-fitting ignition portion 42 into second body portion 23, it is necessary to suppress deformation of ignition portion 42 (i.e. deformation of the squib cup) due to the press-fit as much as possible. This is because, if ignition portion 42 is significantly deformed by the press-fit, this deformation may have a significant effect on the combustion performance of the ignition charge during activation, which may in turn 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 peripheral surface of the housing body 10 where the first crimped portion 11 is formed is in pressure contact with the outer peripheral surface of the second body portion 23 of the second holder 20B, and a compressive force is locally applied to the second body portion 23 at that portion. Therefore, a compressive force is also applied to the ignition portion 42 via the second body portion 23, and there is a risk that the ignition portion 42 will be significantly deformed due to this compressive force. Therefore, when the igniter assembly is crimped to the housing body 10, it is necessary to suppress the deformation of the ignition 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 body portion 23, and it is also possible to prevent deformation of ignition portion 42 as much as possible 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 the ignition portion 42 side.

[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 ignition portion 42 is pressed into second body portion 23 and after it is pressed in, only multiple protrusions 24 abut against the outer peripheral surface of ignition portion 42, and in areas other than 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-fit) is formed between the outer peripheral surface of ignition portion 42 and the inner peripheral surface of second body portion 23.

[0111] Therefore, with this configuration, during and after the press-fitting of ignition portion 42 into second body portion 23, most of the area where ignition portion 42 and second body portion 23 face each other is separated by gap G (i.e., there is no direct contact), and only the tips of multiple protrusions 24 are in pressure contact with ignition portion 42. Therefore, while ignition portion 42 is press-fitted into second body portion 23, it is possible to minimize deformation of ignition portion 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 ignition portion 42 with a relatively weak force, so that most of the compressive force applied to the second trunk portion 23 by reducing the diameter of the housing body 10 is not transmitted to the ignition portion 42 due to the provision of the gap G, but is transmitted to the ignition 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 ignition portion 42 can be suppressed.

[0113] Here, it is preferable that the multiple protrusions 24 are arranged so as not to pinch 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, it is possible to prevent these forces from overlapping in opposite directions on the same straight line), making it possible to more reliably suppress deformation of the ignition part 42.

[0114] Moreover, it is preferable that the multiple protrusions 24 are evenly spaced along the circumferential direction of the second body 23. With this configuration, it is possible to distribute the force applied to the ignition part 42, and therefore it is possible to more reliably suppress deformation of the ignition part 42.

[0115] Based on these considerations, it is most preferable that the multiple protrusions 24 be 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 body portion 23 at a radially outer position of a portion of second body portion 23 of second holder 20B where multiple projections 24 are provided. Groove portion 25 is provided in the axial end face of second body portion 23 on the first holder 20A side.

[0117] With this configuration, the rigidity of the portion of second body 23 where multiple protrusions 24 are provided can be considerably reduced, making it possible to reduce the force applied to ignition part 42 by multiple protrusions 24 when ignition part 42 is pressed into second body 23 and after it has been pressed in. Therefore, while ignition part 42 is being pressed into second body 23, deformation of ignition part 42 can be more reliably suppressed.

[0118] Furthermore, with this configuration, even when the igniter assembly is crimped to the housing body 10, the compression force applied to the second body 23 as a result of the housing body 10 being reduced in diameter is effectively absorbed by the second body 23 due to the provision of the groove 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 making the cylinder-shaped gas generator 1A of this embodiment, it is possible to firmly fix the second holder 20B to the first holder 20A by pressing the ignition portion 42 into the second body portion 23 while suppressing deformation of the ignition portion 42, and by providing the first crimping portion 11 and the second crimping portion 12 on the housing main body 10, it is possible to firmly fix the igniter assembly including the first holder 20A, the second holder 20B, the third holder 20C, and the igniter 40, etc., to the housing main body 10.

[0120] Therefore, by employing the above configuration, it becomes possible to stably fix the holder assembly 20 including the second holder 20B having a function as a directivity imparting member, and further the igniter assembly including the holder assembly 20, so that they cannot move relative to the housing. Therefore, it is possible to prevent the second holder 20B acting as a directivity imparting member from shifting position inside the housing body 10, so that individual differences in the distance between the igniter 40 and the gas generating agent 60 are unlikely to occur, and a cylinder-type gas generator capable of stably obtaining a desired gas output can be obtained.

[0121] Furthermore, when this configuration is adopted, it becomes possible to equip cylindrical gas generator 1A with second holder 20B, which functions as a directional member, with a relatively simple configuration, and this can be assembled through relatively easy assembly work such as pressing in or crimping, thereby also suppressing increases in manufacturing costs.

[0122] Therefore, with cylinder-shaped gas generator 1A according to the present embodiment, it is possible to provide a cylinder-shaped gas generator that can stably obtain a desired gas output while suppressing an increase in manufacturing costs.

[0123] Additionally, in cylinder-shaped gas generator 1A according to the present embodiment, as described above, by providing cover portion 26 on second holder 20B, individual differences are less likely to occur in the distance between igniter 40 and gas generating agent 60. Therefore, in this respect as well, it is possible to provide a cylinder-shaped gas generator that can stably obtain a 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 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. Below, with reference to Fig. 9, a cylinder-shaped gas generator 1B according to the present embodiment will be described.

[0127] As shown in FIG. 9, cylinder-shaped gas generator 1B of the present embodiment differs in configuration from cylinder-shaped gas generator 1A of embodiment 1 described above only in that ignition portion 42 is not press-fitted into second body portion 23 of second holder 20B, but the other configuration is 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 embodiment 1 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, so that a cylinder-type gas generator can be obtained that can stably obtain the desired gas output while suppressing increases in manufacturing costs.

[0129] (Summary of Embodiments 1 and 2) The characteristic configurations of the gas generators disclosed in the above-mentioned first and second embodiments can be summarized as follows.

[0130] [Appendix 1] A cylindrical metal housing body including a combustion chamber in which a gas generating agent is accommodated; a holder assembly that is inserted into an axial opening end of the housing body and includes a hollow portion that extends in a direction parallel to the axial direction of the housing body; an igniter including an ignition part loaded with an ignition charge, a terminal pin connected to the ignition part, and a base part through which the terminal pin is inserted and which supports both the ignition part and the terminal pin, at least a part of which is disposed inside the hollow part 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 includes a first holder made of metal that receives the base to hold the igniter, and a second holder made of resin 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 portion defining the hollow portion and an annular protrusion protruding from the first body portion along a radial direction of the housing main body, The second holder includes a cylindrical second body portion that defines the hollow portion, The housing body has a first crimped portion that is tapered radially inward, and a second crimped portion that is located on the opening end side as viewed from the first crimped portion and that is tapered radially inward, the first holder is fixed to the housing main body by clamping the annular protrusion between the first crimping portion and the second crimping portion in the axial direction of the housing main body, the first crimping portion is covered by the second body portion and is in pressure contact with at least a part of an outer circumferential surface of the second body portion; The second holder further has a lid portion that closes at least a part of the hollow portion located on the opposite side of the base portion as viewed from the ignition portion, thereby isolating the gas generating agent from the ignition portion, A gas generator, wherein the cover portion is disposed at a distance from the ignition portion along an axial direction of the housing body.

[0131] [Appendix 2] The lid portion is provided with a plurality of openings, 2. The gas generator according to claim 1, wherein 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] [Appendix 3] 3. The gas generator according to claim 1, wherein the cover portion is provided at an axial end portion of the second body portion opposite to an axial end portion on the first holder side.

[0133] [Appendix 4] 4. A gas generator as described in any one of appendixes 1 to 3, wherein an axial end portion of the second holder located on the first holder side is fixed to the first holder by being fitted into the first holder.

[0134] [Appendix 5] the holder assembly further includes a third holder made of resin, the third holder being located on the opposite side of the combustion chamber as viewed from the first holder and capable of receiving a connector to be connected to the terminal pin; the third holder includes a cylindrical third body portion defining the hollow portion, 5. A gas generator according to any one of claims 1 to 4, wherein the second crimping portion is in pressure contact with at least a part of an outer circumferential surface of the third body portion.

[0135] [Appendix 6] 6. The gas generator according to claim 5, wherein an axial end portion of the third holder located on the first holder side is fixed to the first holder by being fitted into the first holder.

[0136] (Other forms, etc.) In the above-mentioned first and second embodiments of the present invention, the holder assembly is configured by a first metal holder having a function of holding an igniter, a second resin holder having a function of providing directionality, and a third resin holder having a function of forming a female connector. However, the first holder and the third holder may be a single member. In that case, the single member may be made of metal, and may be provided with a female connector while having a function of holding an igniter.

[0137] In addition, in the above-mentioned 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. Also, if the lid portion itself is configured to be thin and fragile, or the lid portion is provided with scores so that it opens due to the combustion of the ignition charge when the cylindrical gas generator is activated, it is not necessarily necessary to provide an opening in the lid portion.

[0138] Furthermore, the shape, size, number, arrangement, etc. of each component disclosed in the above-mentioned embodiments 1 and 2 of the present invention can naturally be modified in various ways without departing from the spirit of the present invention.

[0139] Furthermore, in the above-mentioned first and second embodiments of the present invention, the present invention has been described as being applied to a cylindrical 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 cylindrical 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 like a cylindrical 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. [Explanation of symbols]

[0141] 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 storage portion, 21b Crimped portion, 22 Annular protrusion, 23 Second body portion, 23a Second storage portion, 23b First annular step portion, 24 Protrusion portion, 25 Groove portion, 26 Lid portion, 26a Opening portion, 27 Third body portion, 27a Third storage portion, 27b Second annular step portion, 28 Seal member, 30 Closure member, 40 Igniter, 41 Base portion, 42 Ignition portion, 43 Terminal pin, 50 Partition member, 51 Bulkhead 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 welding portion, G gap portion, S1 combustion chamber, S2 filter chamber.

Claims

1. A cylindrical metal housing body including a combustion chamber in which a gas generating agent is accommodated; a holder assembly including a hollow portion that is inserted into an axial opening end of the housing body and extends along a direction parallel to the axial direction of the housing body; an igniter including an ignition part loaded with an ignition charge, a terminal pin connected to the ignition part, and a base part through which the terminal pin is inserted and which supports both the ignition part and the terminal pin, at least a part of which is disposed inside the hollow part 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 includes a first holder made of metal that receives the base to hold the igniter, and a second holder made of resin 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 portion defining the hollow portion and an annular protrusion protruding from the first body portion along a radial direction of the housing main body, the second holder includes a cylindrical second body portion defining the hollow portion, The housing body has a first crimped portion whose diameter is reduced toward the inside in the radial direction, and a second crimped portion which is located on the opening end side as viewed from the first crimped portion and whose diameter is reduced toward the inside in the radial direction, the first holder is fixed to the housing body by clamping the annular protrusion between the first crimping portion and the second crimping portion in the axial direction of the housing body, The first crimping portion is covered by the second body portion and is in pressure contact with at least a part of an outer circumferential surface of the second body portion, the second holder further includes a lid portion that closes at least a part of the hollow portion at a portion located on the opposite side of the base portion as viewed from the ignition portion, thereby isolating the gas generating agent from the ignition portion; A gas generator, wherein the cover portion is disposed at a distance from the ignition portion along an axial direction of the housing body.

2. The lid portion is provided with a plurality of openings, 2. The gas generator according to claim 1, wherein a maximum outer dimension of each of the plurality of openings when viewed in the axial direction of the housing body is smaller than a minimum outer dimension of the gas generating agent.

3. 2 . The gas generator according to claim 1 , wherein the cover portion is provided at an axial end portion of the second body portion that is located opposite to an axial end portion on a side of the first holder.

4. 2 . The gas generator according to claim 1 , wherein an axial end portion of said second holder located on said first holder side is fitted into said first holder and thereby fixed to said first holder.

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

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

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