Gas generator

Abstract

To provide a gas generator which can exert a sufficient gas output performance even if an amount of transfer charge is comparatively small.SOLUTION: A gas generator 100 includes: an igniter 40 which has a housing constituted of a peripheral wall section 22 provided with a gas injection port 23, an upper section side shell 20 for closing one end in an axial direction of the peripheral wall section 22, and a lower section side shell 10 for closing the other end in the axial direction of the peripheral wall section 22 and having a combustion chamber 60 storing a gas generating agent 61 therein and an ignition section assembled to the lower section side shell 10 and storing ignition charge; a bottomed cylindrical cup-shaped member 50 which has a transfer charge chamber 57 storing transfer charge 59 therein and is arranged to project toward the combustion chamber 60 so that a space in the transfer charge chamber 57 faces the ignition section; and a cushion material 85 which is arranged on the lower section side shell 10 side and supports the gas generating agent 61 from the lower section side shell 10 side. At least a part of the gas generating agent 61 is arranged between the cup-shaped member 50 and the lower section side shell 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gas generator incorporated in an occupant protection device for protecting an occupant in the event of a vehicle collision, and more particularly to a gas generator incorporated in an airbag device mounted on an automobile or the like. [Background technology]

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

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

[0004] Gas generators have a variety of structures, but a gas generator that is particularly suitable for use in a driver's side airbag device, a passenger's side airbag device, etc. is a short, approximately cylindrical disk-type gas generator with a relatively large outer diameter.

[0005] A disk-type gas generator has a short, approximately cylindrical housing with both axial ends closed, a plurality of gas outlets provided in the peripheral wall of the housing, a transfer charge contained inside the housing so as to face an igniter assembled to the housing, a gas generating agent filled inside the housing so as to surround the transfer charge, and a filter contained inside the housing so as to further surround the gas generating agent.

[0006] For example, Patent Document 1 discloses a disk-type gas generator equipped with a cushioning material for preventing the gas generating agent from being pulverized by vibrations, etc. in a combustion chamber provided in a housing. The cushioning material in Patent Document 1 is disposed so as to face the top surface of a cup body filled with a transfer charge. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-312434 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0008] In the gas generator of Patent Document 1, if the distance between the cushion material and the top surface of the cup body is relatively short, the transfer charge may be adsorbed to the cushion material when the igniter is activated, causing the transfer charge to be deactivated. This reduces the amount of transfer charge that can be transferred to the gas generant, making it impossible to obtain sufficient gas output performance. Possible solutions to this problem include ensuring a sufficient distance between the cushion material and the top surface of the cup body, or increasing the size of the cup body to increase the amount of transfer charge. However, a configuration in which a sufficient distance between the cushion material and the top surface of the cup body is provided poses the problem of increasing the size of the gas generator. Furthermore, even if a certain amount of distance is provided between the cushion material and the top surface of the cup body, there is a problem that the transfer charge may be adsorbed to the cushion material to some extent, making it impossible to obtain the desired gas output performance. Furthermore, increasing the size of the cup body to increase the amount of transfer charge increases the problem of increasing the total weight of the gas generator.

[0009] Therefore, the present invention has been made in consideration of the above circumstances, and has an object to provide a gas generator that can exhibit sufficient gas output performance even when the amount of transfer charge is relatively small. [Means for solving the problem]

[0010] (1) A gas generator of the present invention comprises a short cylindrical housing having a combustion chamber therein, the housing being constituted by a cylindrical peripheral wall portion provided with a gas outlet, a top plate portion closing one axial end of the peripheral wall portion, and a bottom plate portion closing the other axial end of the peripheral wall portion, and having a gas generating agent accommodated therein; an igniter assembled to the bottom plate portion and including an ignition portion containing an ignition charge that ignites when activated; a cup-shaped member consisting of a single cylindrical member with a bottom, the cup-shaped member containing a transfer chamber containing an ignition charge and arranged to protrude toward the combustion chamber so that the internal space of the transfer chamber faces the ignition portion; and a cushioning material arranged on the bottom plate side and supporting the gas generating agent from the bottom plate side. An approximately disk-shaped upper support member is disposed at an end of the combustion chamber that is located on the top plate side, At least a portion of the gas generating agent is connected to the cup-shaped member. The upper support member is disposed between the upper support member and the It is characterized by the presence of The cup-shaped member also includes a top wall portion having a thin-walled fragile portion at least in part thereof, and a side wall portion of the cup-shaped member that separates the transfer chamber from the combustion chamber and has a higher mechanical strength than the fragile portion. The side wall portion also includes a thin-walled portion provided on the top wall portion side and a thick-walled portion extending from the thin-walled portion along the axial direction to the opposite side from the top wall portion, the fragile portion being disposed opposite the ignition portion and having a mechanical strength such that the cup-shaped member ruptures, deforms, or melts before the side wall portion does upon activation of the igniter, and the thin-walled portion has a mechanical strength such that the cup-shaped member ruptures, deforms, or melts if the rupture, deformation, or melting in the fragile portion extends to the thin-walled portion. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a gas generator that can exhibit sufficient gas output performance even when the amount of transfer charge is relatively small. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view of a disk-type gas generator according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view of a cup-shaped member of the disk-type gas generator of FIG. 1. [Figure 3] FIG. 2 is a schematic cross-sectional view for explaining the operation of the disk-shaped gas generator of FIG. 1. [Figure 4] FIG. 10 is a schematic cross-sectional view of a disk-type gas generator according to a modified example of the embodiment of the present invention. [Figure 5] FIG. 1 is a schematic cross-sectional view of a disk-type gas generator according to comparative examples 1 and 2 of verification test 1. [Figure 6] FIG. 10 is a schematic cross-sectional view of a disk-shaped gas generator according to Comparative Example 3 of Verification Test 1 and Comparative Example 4 of Verification Test 2. [Figure 7] FIG. 1 is a diagram showing test conditions and test results of verification test 1. [Figure 8] FIG. 10 is a diagram showing test conditions and test results of verification test 2. [Figure 9] FIG. 10 is a diagram showing test conditions and test results of verification test 3. [Figure 10] FIG. 10 is a schematic cross-sectional view of a disk-type gas generator according to a modified example of the embodiment of the present invention. [Figure 11] FIG. 10 is a diagram showing test conditions and test results of verification test 4. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiments shown below, the present invention is applied to a disc-type gas generator that is suitably incorporated into an airbag device mounted on the steering wheel of an automobile, etc. In the embodiments shown below, identical or common parts are designated by the same reference numerals in the drawings, and their description will not be repeated.

[0016] Fig. 1 is a schematic diagram of a disk-shaped gas generator 100 in an embodiment of the present invention. First, with reference to Fig. 1, the configuration of disk-shaped gas generator 100 in the present embodiment will be described.

[0017] 1, disk-type gas generator 100 has a short, substantially cylindrical housing with one axial end and the other end closed, and an accommodating space provided inside this housing accommodates internal components such as retaining section 30, igniter 40, cup-shaped member 50, transfer charge 59, gas generating agent 61, lower support member 70, upper support member 80, cushion material 85, and filter 90. Also, a combustion chamber 60 is located in the accommodating space provided inside the housing, and primarily accommodates gas generating agent 61, one of the above-mentioned internal components.

[0018] The housing includes a lower shell 10 and an upper shell 20. Each of the lower shell 10 and the upper shell 20 is a press-molded product formed, for example, by pressing a rolled metal plate-like member. The metal plate-like members constituting the lower shell 10 and the upper shell 20 are made of metal plates made of, for example, stainless steel, iron steel, aluminum alloy, stainless alloy, etc., and preferably so-called high-tensile steel plates that do not break or otherwise damage even when a tensile stress of 440 MPa or more and 780 MPa or less is applied are used.

[0019] The lower shell 10 and the upper shell 20 are each formed in a generally cylindrical shape with a bottom, and are assembled and joined together with their open surfaces facing each other to form a housing. The lower shell 10 has a bottom plate portion 11 and a peripheral wall portion 12, and the upper shell 20 has a top plate portion 21 and a peripheral wall portion 22.

[0020] The upper end of the peripheral wall 12 of the lower shell 10 is inserted into the lower end of the peripheral wall 22 of the upper shell 20 and press-fitted. Furthermore, the peripheral wall 12 of the lower shell 10 and the peripheral wall 22 of the upper shell 20 are joined at or near their abutment, thereby fixing the lower shell 10 and the upper shell 20 together. Here, electron beam welding, laser welding, friction welding, or the like can be suitably used to join the lower shell 10 and the upper shell 20 together.

[0021] As a result, the portion of the peripheral wall of the housing closer to the bottom plate 11 is formed by the peripheral wall 12 of the lower shell 10, and the portion of the peripheral wall of the housing closer to the top plate 21 is formed by the peripheral wall 22 of the upper shell 20. One end and the other end in the axial direction of the housing are closed by the bottom plate 11 of the lower shell 10 and the top plate 21 of the upper shell 20, respectively.

[0022] A protruding cylindrical portion 13 that protrudes toward the top plate portion 21 is provided in the center of the bottom plate portion 11 of the lower shell 10, thereby forming a recessed portion 14 in the center of the bottom plate portion 11 of the lower shell 10. The protruding cylindrical portion 13 is a portion where the igniter 40 is fixed via the holding portion 30, and the recessed portion 14 is a portion that provides space for providing the female connector portion 34 in the holding portion 30.

[0023] Protruding tube portion 13 is formed in a generally cylindrical shape with a bottom, and an opening 15 having a point-asymmetric shape (for example, a D-shape, a barrel shape, an oval shape, or the like) in a plan view is provided at its axial end portion located on the top plate portion 21 side. Opening 15 is a portion through which a pair of terminal pins 42 of igniter 40 are inserted.

[0024] Igniter 40 is for generating a flame and includes ignition unit 41 and the above-mentioned pair of terminal pins 42. Igniter unit 41 contains an ignition charge that ignites and burns to generate a flame when activated, and a resistor for igniting the ignition charge. The pair of terminal pins 42 are connected to ignition unit 41 to ignite the ignition charge.

[0025] More specifically, the ignition unit 41 comprises a cup-shaped squib cup and a plug that closes the open end of the squib cup and through which a pair of terminal pins 42 are inserted and held; a resistor (bridge wire) is attached to connect the tips of the pair of terminal pins 42 inserted into the squib cup; and an ignition charge is loaded into the squib cup so as to surround or be close to the resistor.

[0026] Here, nichrome wire is generally used as the resistor, and ZPP (zirconium potassium perchlorate), ZWPP (zirconium tungsten potassium perchlorate), lead tricinate, etc. are generally used as the ignition charge. The squib cup and plug mentioned above are generally made of metal or plastic.

[0027] When a collision is detected, a predetermined amount of current flows through the resistor via the terminal pin 42. This current flow generates Joule heat in the resistor, causing the ignition charge to begin burning. The high-temperature flame generated by the combustion ruptures 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 ms or less when nichrome wire is used for the resistor.

[0028] Igniter 40 is attached to bottom plate 11 in a state where it is inserted from the inside of lower shell 10 so that terminal pin 42 passes through opening 15 provided in protruding cylindrical portion 13. Specifically, a holding portion 30 made of a resin molded portion is provided around protruding cylindrical portion 13 provided on bottom plate 11, and igniter 40 is fixed to bottom plate 11 by being held by holding portion 30.

[0029] The retaining portion 30 is formed by injection molding (more specifically, insert molding) using a mold, and is formed by adhering an insulating fluid resin material to the bottom plate portion 11 of the lower shell 10 so that it passes through an opening 15 provided in the bottom plate portion 11 and reaches from a portion of the inner surface of the bottom plate portion 11 to a portion of the outer surface, and then solidifying it.

[0030] As the raw material for the holding portion 30 formed by injection molding, a resin material that exhibits excellent heat resistance, durability, corrosion resistance, and the like after hardening is preferably selected and used. In this case, it is not limited to thermosetting resins such as epoxy resin, but thermoplastic resins such as polybutylene terephthalate resin, polyethylene terephthalate resin, polyamide resin (e.g., nylon 6, nylon 66, etc.), polypropylene sulfide resin, and polypropylene oxide resin can also be used. When such a thermoplastic resin is selected as the raw material, it is preferable to incorporate glass fiber or the like as a filler into the resin material to ensure the mechanical strength of the holding portion 30 after molding. However, if sufficient mechanical strength can be ensured with the thermoplastic resin alone, it is not necessary to add the filler described above.

[0031] The retaining portion 30 has an inner covering portion 31 that covers part of the inner surface of the bottom plate portion 11 of the lower shell 10, an outer covering portion 32 that covers part of the outer surface of the bottom plate portion 11 of the lower shell 10, and a connecting portion 33 that is located within the opening 15 provided in the bottom plate portion 11 of the lower shell 10 and is continuous with the inner covering portion 31 and the outer covering portion 32, respectively.

[0032] The retaining portion 30 is fixed to the bottom plate portion 11 on the surfaces of the inner covering portion 31, the outer covering portion 32, and the connecting portion 33 that face the bottom plate portion 11. The retaining portion 30 is also fixed to the side and bottom surfaces of the ignition portion 41 of the igniter 40 near the lower end, and to the surface of the terminal pin 42 of the igniter 40 near the upper end.

[0033] As a result, opening 15 is completely filled with terminal pin 42 and holding portion 30, and the sealing of this portion ensures airtightness of the space inside the housing. Since opening 15 is formed in an asymmetrical shape in a plan view as described above, by filling opening 15 with connecting portion 33, opening 15 and connecting portion 33 also function as an anti-rotation mechanism that prevents holding portion 30 from rotating relative to bottom plate portion 11.

[0034] A female connector portion 34 is formed on the portion of the outer covering portion 32 of the holding portion 30 facing outward. This female connector portion 34 is a portion for receiving a male connector (not shown) of a harness for connecting the igniter 40 to a control unit (not shown), and is located in a recess 14 provided in the bottom plate portion 11 of the lower shell 10.

[0035] A portion of the terminal pin 42 of the igniter 40 near the lower end is exposed and disposed within this female connector portion 34. A male connector is inserted into the female connector portion 34, thereby establishing electrical continuity between the core wire of the harness and the terminal pin 42.

[0036] The above-described injection molding may also be performed using a lower shell 10 in which an adhesive layer is provided in advance at a predetermined position on the surface of the bottom plate portion 11 in the portion that will be covered by the holding portion 30. The adhesive layer can be formed by applying adhesive to a predetermined position on the bottom plate portion 11 in advance and then curing the adhesive.

[0037] In this way, the hardened adhesive layer is positioned between the bottom plate portion 11 and the holding portion 30, so that the holding portion 30, which is made of a resin molded portion, can be more firmly fixed to the bottom plate portion 11. Therefore, if the adhesive layer is provided in a ring shape along the circumferential direction so as to surround the opening 15 provided in the bottom plate portion 11, it is possible to ensure higher sealing performance in that portion.

[0038] Here, the adhesive to be applied in advance to the bottom plate portion 11 is preferably one containing as a raw material a resin material that has excellent heat resistance, durability, corrosion resistance, etc. after hardening, and is particularly preferably one containing as a raw material a cyanoacrylate resin or a silicone resin. In addition to the above-mentioned resin materials, materials containing raw materials such as phenolic resins, epoxy resins, melamine resins, urea resins, polyester resins, alkyd resins, polyurethane resins, polyimide resins, polyethylene resins, polypropylene resins, polyvinyl chloride resins, polystyrene resins, polyvinyl acetate resins, polytetrafluoroethylene resins, acrylonitrile butadiene styrene resins, acrylonitrile styrene resins, acrylic resins, polyamide resins, polyacetal resins, polycarbonate resins, polyphenylene ether resins, polybutylene terephthalate resins, polyethylene terephthalate resins, polyolefin resins, polyphenylene sulfide resins, polysulfone resins, polyethersulfone resins, polyarylate resins, polyetheretherketone resins, polyamideimide resins, liquid crystal polymers, styrene rubbers, and olefin rubbers can also be used as the above-mentioned adhesives.

[0039] Here, an example of a configuration has been given in which the igniter 40 can be fixed to the lower shell 10 by injection molding the retaining portion 30 made of a resin molded portion, but other alternative means can also be used to fix the igniter 40 to the lower shell 10.

[0040] A cup-shaped member 50 is attached to the bottom plate 11 so as to cover the protruding tube 13, the holding portion 30, and the igniter 40. The cup-shaped member 50 has a generally cylindrical shape with a bottom that is open at the end on the bottom plate 11 side, and includes a space therein for accommodating a transfer charge 59. The cup-shaped member 50 is positioned so that it protrudes into the combustion chamber 60 that accommodates the gas generating agent 61, with the space provided therein facing the ignition portion 41 of the igniter 40.

[0041] The cup-shaped member 50 has a top wall portion 51, a cylindrical side wall portion 52 extending from the periphery of the top wall portion 51 toward the bottom plate portion 11, and an extension portion 53 extending radially outward from the opening end, which is the end of the side wall portion 52 on the bottom plate portion 11 side.

[0042] The side wall 52 includes a thin portion 52a provided on the top wall 51 side, and a thick portion 52b extending from the thin portion 52a along the axial direction to the opposite side of the top wall 51. The thin portion 52a is thicker than the fragile portion 55 described below and thinner than the thick portion 52b, and has the mechanical strength to rupture (break), deform, or melt in accordance with the rupture (break), deformation, or melting of the fragile portion 55.

[0043] The extension portion 53 is formed to extend along the inner surface of the bottom plate portion 11 of the lower shell 10. Specifically, the extension portion 53 has a curved shape to follow the shape of the inner bottom surface of the bottom plate portion 11 at and near the portion where the protruding tubular portion 13 is provided, and includes a tip portion 54 extending in a flange shape at its radially outer portion.

[0044] The tip 54 of the extension 53 is disposed between the bottom plate 11 and the lower support member 70 along the axial direction of the housing, and is thereby sandwiched between the bottom plate 11 and the lower support member 70 along the axial direction of the housing. As a result, the tip 54 of the extension 53 of the cup-shaped member 50 is pressed toward the bottom plate 11 by the lower support member 70, and the cup-shaped member 50 is fixed to the bottom plate 11. This prevents the cup-shaped member 50 from falling off the bottom plate 11 without using crimping or press-fitting to fix the cup-shaped member 50.

[0045] Cup-shaped member 50 has no openings in either side wall 52 or top wall 51, and surrounds an internal space. When transfer charge 59 in transfer chamber 57 is ignited by activation of igniter 40, cup-shaped member 50 bursts, deforms, or melts due to an increase in pressure in the internal space and conduction of the generated heat.

[0046] Suitable materials for the cup-shaped member 50 include metal members such as stainless steel, steel, aluminum, aluminum alloy, stainless steel, stainless steel alloy, etc., and resin members such as thermosetting resins typified by epoxy resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polyamide resin (e.g., nylon 6, nylon 66, etc.), polypropylene sulfide resin, polypropylene oxide resin, etc. In particular, aluminum alloys or iron-based metal materials such as stainless steel and steel, which have relatively higher mechanical strength than aluminum, are preferred.

[0047] The method for fixing the cup-shaped member 50 is not limited to the above-described fixing method using the lower support member 70, and other fixing methods may be used.

[0048] At least a portion of the top wall 51 of the cup-shaped member 50 is provided with a weak portion 55 that is thinner than the side wall 52. As shown in Fig. 2, the weak portion 55 is provided by a radially extending slit, and is configured to have lower mechanical strength than the side wall 52 of the cup-shaped member 50. The weak portion 55 is disposed so as to face the ignition portion 41 of the igniter 40. In addition, the portion of the top wall 51 other than the radially extending weak portion 55 is provided with a non-weak portion 56 that is thicker than the weak portion 55 and has a thickness approximately the same as that of the thick portion 52b.

[0049] As a result, in the space inside cup-shaped member 50, weak portion 55 ruptures (breaks), deforms, or melts due to the thrust generated by the combustion of transfer charge 59, and then thin-walled portion 52a ruptures (breaks), deforms, or melts in accordance with the rupture (break), deformation, or melting of weak portion 55, and the mechanical strength of weak portion 55 and thin-walled portion 52a is relatively low. On the other hand, non-weak portion 56 and thick portion 52b are formed thicker than weak portion 55, and are therefore configured to remain even after the combustion of transfer charge 59 accompanying the activation of igniter 40.

[0050] The thicknesses of the fragile portion 55 and thin portion 52a and the non-fragile portion 56 and thick portion 52b are adjusted as appropriate based on the type and filling amount of the transfer charge 59 used, and an example is shown below. For example, when the cup-shaped member is made of iron, stainless steel, or an aluminum alloy, the thicknesses of the fragile portion 55 and thin portion 52a are set to 0.6 mm or less, preferably 0.5 mm or less. On the other hand, when the cup-shaped member is made of iron, stainless steel, or an aluminum alloy, the thicknesses of the non-fragile portion 56 and thick portion 52b are set to 0.6 mm or more and 1.5 mm or less, preferably 0.6 mm or more and 1.2 mm or less, provided that they are greater than the thicknesses of the fragile portion 55 and thin portion 52a.

[0051] 2, the fragile portion 55 may be made up of any number of slits as long as the slits constituting the fragile portion 55 are arranged radially. For example, the fragile portion 55 may be made up of slits arranged in a cross or asterisk shape in plan view.

[0052] The transfer charge 59 filled in the transfer chamber 57 is ignited by the flame generated by the activation of the igniter 40, and generates thermal particles as it burns. The transfer charge 59 must be capable of reliably starting the combustion of the gas generant 61, and generally, a composition made of a metal powder / oxidizer, such as B / KNO3, B / NaNO3, or Sr(NO3)2, a composition made of titanium hydride / potassium perchlorate, or a composition made of B / 5-aminotetrazole / potassium nitrate / molybdenum trioxide, is used.

[0053] The enhancer charge 59 may be in a powder form, or may be formed into a predetermined shape using a binder. The enhancer charge 59 formed using a binder may have various shapes, such as granules, cylinders, sheets, spheres, single-hole cylinders, multi-hole cylinders, tablets, and the like.

[0054] Within the space inside the housing, a combustion chamber 60 containing a gas generating agent 61 is located in the space surrounding the portion in which the cup-shaped member 50 is disposed. Specifically, as described above, the cup-shaped member 50 is disposed so as to protrude into the combustion chamber 60 formed inside the housing, and the space provided in the portion facing the outer surface of the top wall portion 51 of the cup-shaped member 50 and the space provided in the portion facing the outer surface of the side wall portion 52 form the combustion chamber 60. As a result, the gas generating agent 61 is disposed adjacent to the outer surface of the cup-shaped member 50.

[0055] Furthermore, a filter 90 is disposed along the inner periphery of the housing in the space that radially surrounds the combustion chamber 60 that accommodates the gas generating agent 61. The filter 90 has a cylindrical shape and is disposed so that its central axis substantially coincides with the axial direction of the housing.

[0056] The gas generating agent 61 is an agent that is ignited by thermal particles generated by the transfer charge 59 when the igniter 40 is activated, and burns to generate gas. A non-azide gas generating agent is preferably used as the gas generating agent 61, and the gas generating agent 61 is generally formed as a molded body containing a fuel, an oxidizer, and an additive.

[0057] 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.

[0058] Examples of oxidizing agents that can be used include basic metal nitrates such as basic copper nitrate, basic metal carbonates such as 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.

[0059] Examples of additives include binders, slag formers, and combustion modifiers. Suitable binders include organic binders such as polyvinyl alcohol, metal salts of carboxymethyl cellulose, and stearates, as well as inorganic binders such as synthetic hydrotalcite and acid clay. Other suitable binders include polysaccharide derivatives such as hydroxyethyl cellulose, hydroxypropyl methyl cellulose, cellulose acetate, cellulose propionate, cellulose acetate butyrate, nitrocellulose, microcrystalline cellulose, guar gum, polyvinylpyrrolidone, polyacrylamide, and starch, as well as inorganic binders such as molybdenum disulfide, talc, bentonite, diatomaceous earth, kaolin, and alumina. Suitable slag formers include silicon nitride, silica, and acid clay. Suitable combustion modifiers include metal oxides, ferrosilicon, activated carbon, and graphite.

[0060] The shape of the molded body of gas generating agent 61 may be various, including granular, pellet-like, cylindrical, or other particulate shapes, and disc-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 as appropriate depending on the specifications of the airbag device into which disk-shaped gas generator 100 is incorporated, and it is preferable to select an optimal shape depending on the specifications, such as selecting a shape in which the gas generation rate changes over time when gas generating agent 61 is burned. Furthermore, in addition to the shape of gas generating agent 61, it is preferable to select the size and filling amount of the molded body as appropriate, taking into consideration the burning rate, pressure exponent, etc. of gas generating agent 61.

[0061] The filter 90 can be made of, for example, metal wire such as stainless steel or iron, wound and sintered, or a mesh of woven metal wires pressed together. Specific examples of mesh materials that can be used include knitted wire mesh, plain woven wire mesh, and an aggregate of crimped metal wires.

[0062] Alternatively, a perforated metal sheet wound around the filter 90 may be used. Examples of perforated metal sheets include expanded metal, which is a metal sheet with staggered cuts and then expanded to form holes and form a mesh, and hook metal, which is a metal sheet with holes drilled and flattened by crushing any burrs that may form around the holes. The size and shape of the holes can be varied as needed, and holes of different sizes and shapes may be included in the same metal sheet. Suitable metal sheets include mild steel and stainless steel, as well as non-ferrous metal sheets such as aluminum, copper, titanium, nickel, and alloys thereof.

[0063] The filter 90 functions as a cooling means for cooling the gas generated in the combustion chamber 60 by removing the high-temperature heat of the gas as the gas passes through the filter 90, and also functions as a removal means for removing residue (slag) and the like contained in the gas. Therefore, in order to sufficiently cool the gas and prevent the residue from being released to the outside, it is necessary to ensure that the gas generated in the combustion chamber 60 passes through the filter 90. The filter 90 is disposed at a distance from the peripheral wall portions 12, 22 of the lower shell 10 and the peripheral wall portion 22 of the upper shell 20 that constitute the peripheral wall portions of the housing so that a gap 28 of a predetermined size is formed between the filter 90 and the peripheral wall portions 12, 22.

[0064] A plurality of gas outlets 23 are provided in the peripheral wall 22 of the upper shell 20 in a portion facing the filter 90. The plurality of gas outlets 23 are for directing the gas that has passed through the filter 90 to the outside of the housing.

[0065] Additionally, a metal sealing tape 24 is attached to the inner peripheral surface of the peripheral wall portion 22 of the upper shell 20 as a sealing member to close the plurality of gas ejection ports 23. As this sealing tape 24, an aluminum foil with an adhesive member applied to one side can be suitably used, and the sealing tape 24 ensures the airtightness of the combustion chamber 60.

[0066] A lower support member 70 is disposed near the end of the combustion chamber 60 on the bottom plate 11 side. The lower support member 70 has an annular shape and is disposed substantially between the filter 90 and the bottom plate 11 so as to cover the boundary between the filter 90 and the bottom plate 11. As a result, the lower support member 70 is positioned between the bottom plate 11 and the cushion material 85 near the end of the combustion chamber 60.

[0067] The lower support member 70 has an annular plate-shaped base portion 71 that is fitted to the bottom plate portion 11 so as to fit along the inner bottom surface of the bottom plate portion 11, an abutting portion 72 that abuts against the inner peripheral surface of the filter 90 closer to the bottom plate portion 11, and a tubular upright portion 73 that stands from the base portion 71 toward the top plate portion 21. The abutting portion 72 extends from the outer edge of the base portion 71, and the upright portion 73 extends from the inner edge of the base portion 71. The upright portion 73 covers the outer peripheral surface of the protruding tubular portion 13 of the lower shell 10 and the outer peripheral surface of the inner covering portion 31 of the holding portion 30 via the extension portion 53 of the cup-shaped member 50.

[0068] The lower support member 70 is a member for fixing the filter 90 to the housing, and also functions as an outflow prevention means for preventing gas generated in the combustion chamber 60 from flowing out through the gap between the lower end of the filter 90 and the bottom plate portion 11 without passing through the inside of the filter 90 when the igniter 40 is activated. For this reason, the lower support member 70 is formed, for example, by pressing a metal plate-shaped member, and is preferably made of a member made of a steel plate such as ordinary steel or special steel (for example, a cold-rolled steel plate or a stainless steel plate).

[0069] A circular plate-shaped cushion material 85 is disposed on the upper surface of the base 71 of the lower support member 70 so as to come into contact with the gas generating agent 61 contained in the combustion chamber 60. The cushion material 85 is provided for the purpose of preventing the gas generating agent 61 made of a molded body from being crushed by vibration or the like, and is preferably made of a member made of a ceramic fiber molded body, rock wool, foamed resin (for example, foamed silicone, foamed polypropylene, foamed polyethylene, foamed urethane, etc.), rubber typified by chloroprene and EPDM, or the like.

[0070] Here, the cushion material 85 is located between the bottom plate portion 11 and the gas generating agent 61 in the portion of the combustion chamber 60 on the bottom plate portion 11 side. Therefore, the cushion material 85 presses the gas generating agent 61 toward the top plate portion 21 side.

[0071] Furthermore, cushion material 85 is provided at a position spaced a predetermined distance from top wall portion 51 of cup-shaped member 50. Therefore, when igniter 40 is activated, transfer charge 59 is able to reach gas generating agent 61 and transfer flame without being adsorbed to cushion material 85, so gas generating agent 61 can be burned efficiently and the gas output performance of gas generator 100 can be made as desired.

[0072] Furthermore, because the cushion material 85 is provided on the bottom plate 11 side of the combustion chamber 60, a larger amount of gas generating agent 61 can be disposed between the top wall 51 and the top plate 21 of the cup-shaped member 50 than when the cushion material 85 is provided on the top plate 21 side of the combustion chamber 60. As a result, a larger amount of gas can be generated when the igniter 40 is activated. The amount of gas generated is adjusted appropriately based on the amount of gas generating agent 61 disposed between the top wall 51 and the top plate 21 of the cup-shaped member 50, and an example is shown below. For example, it is preferable that the height (distance from the top plate 21 or the upper support member 80) of the charge surface (the uppermost position of the gas generating agent 61) of the gas generating agent 61 disposed above the top wall 51 is 5 mm or more and 20 mm or less.

[0073] An upper support member 80 is disposed at the end of the combustion chamber 60 that is located on the top plate portion 21 side. The upper support member 80 has a substantially disk-like shape, and is disposed between the filter 90 and the top plate portion 21 so as to cover the boundary between the filter 90 and the top plate portion 21. As a result, the upper support member 80 is positioned near the end of the combustion chamber 60, between the top plate portion 21 and the gas generating agent 61.

[0074] The upper support member 80 has a base 81 that abuts against the top plate 21, and an abutment portion 82 that stands upright from the periphery of the base 81. The abutment portion 82 abuts against the inner circumferential surface of the axial end portion of the filter 90 that is located on the top plate 21 side.

[0075] The upper support member 80 is a member for fixing the filter 90 to the housing, and also functions as an outflow prevention means for preventing gas generated in the combustion chamber 60 from flowing out through the gap between the upper end of the filter 90 and the top plate portion 21 without passing through the inside of the filter 90 when the igniter 40 is activated. For this reason, the upper support member 80 is formed, for example, by pressing a metal plate-shaped member, and is preferably made of a member made of a steel plate such as ordinary steel or special steel (for example, a cold-rolled steel plate or a stainless steel plate).

[0076] Next, with reference to FIG. 1, a procedure for assembling disk-shaped gas generator 100 in the present embodiment will be described.

[0077] First, the igniter 40 is fixed to the lower shell 10 by injection molding the retaining portion 30, which is made of a resin molded portion. Then, the side wall portion 52 of the cup-shaped member 50, which contains the transfer charge 59, is press-fitted into the retaining portion 30 of the lower shell 10 to fix it. Next, the lower support member 70 is placed on the tip portion 54 of the extension portion 53 of the cup-shaped member 50, and the filter 90 is inserted and positioned toward the inner bottom surface of the lower shell 10.

[0078] Then, cushioning material 85 is placed on the upper surface of base 71 of lower support member 70, gas generating agent 61 is filled inside filter 90, and upper support member 80 is inserted into the upper end portion of filter 90. Thereafter, upper shell 20, with gas ejection port 23 closed with sealing tape 24, is placed over lower shell 10, and lower shell 10 and upper shell 20 are welded together. This completes the assembly of disc-type gas generator 100 having the structure shown in FIG. 1 .

[0079] Here, in disk-shaped gas generator 100 in the present embodiment, no opening is provided in cup-shaped member 50, and therefore the step of filling transfer charge 59 into transfer chamber 57 provided inside cup-shaped member 50 can be carried out very easily. This is because cup-shaped member 50 itself is constructed of a fragile member with low mechanical strength so that a part of the cup-shaped member will rupture, deform or melt when disk-shaped gas generator 100 is activated. In other words, the work of closing the opening provided in the cup-shaped member in order to fill it with transfer charge 59, such as with aluminum tape or a closing plate, which was necessary when a cup-shaped member having an opening was used, is no longer necessary, and the manufacturing process can be greatly simplified.

[0080] Fig. 3 is a schematic cross-sectional view for illustrating the operation of disk-shaped gas generator 100 in the present embodiment. Next, with reference to Fig. 3 and the above-mentioned Fig. 1, the operation of disk-shaped gas generator 100 in the present embodiment will be described.

[0081] 1, when a vehicle equipped with disk-shaped gas generator 100 collides, the collision is detected by collision detection means separately provided in the vehicle, and based on this, a control unit separately provided in the vehicle supplies current to activate igniter 40. Transfer charge 59 accommodated in transfer chamber 57 is ignited by a flame generated by the activation of igniter 40, and begins to burn.

[0082] At this time, as shown in FIG. 3, immediately after the igniter 40 is activated, the ignition charge loaded in the ignition section 41 rapidly burns, causing the squib cup of the ignition section 41 to burst, and the heat generated by the rapid combustion of the ignition charge is transmitted to the transfer charge 59 filled in the transfer chamber 57.

[0083] As shown in FIG. 3 , when the thrust reaches the top wall 51 of the cup-shaped member 50, the fragile portion 55 of the cup-shaped member 50, which is made of a fragile material, ruptures, deforms, or melts. This rupture, deformation, or melting of the fragile portion 55 of the cup-shaped member 50 occurs later than the ignition of the transfer charge 59 by heat particles generated by the combustion of the ignition charge. Note that since the side wall 52 does not have the fragile portion 55 but the top wall 51 does, the fragile portion 55 of the top wall 51 ruptures, deforms, or melts, and the internal pressure rises until the top wall 51 ruptures, deforms, or melts. Here, the transfer charge 59 of the cup-shaped member 50 is subjected to the thrust generated by the combustion of the ignition charge and is scattered and dispersed within the cup-shaped member 50. 2, the fragile portion 55 is provided as a slit, and ruptures, deforms, or melts from the top wall portion 51 of the cup-shaped member 50 first, and then tears open toward the thin-walled portion 52a of the side wall portion 52. In accordance with the rupture (break), deformation, or melting of the fragile portion 55, the thin-walled portion 52a ruptures (breaks), deforms, or melts, and tears open all the way to the connection portion with the thick-walled portion 52b. Here, the thick-walled portion 52b does not rupture (break), deform, or melt.

[0084] Therefore, the transfer charge 59 located farther from the igniter 40 is also ignited by the thermal particles in a shorter time and begins to burn, which results in a significant increase in pressure and temperature in the space inside the cup-shaped member 50. As a result, the weak portion 55 of the cup-shaped member 50 ruptures, deforms, or melts in a shorter time, and a large amount of thermal particles generated by the combustion of the transfer charge 59 flows into the combustion chamber 60 quickly. These thermal particles are not affected by the cushioning material 85 provided in the lower shell 10 and come into contact with the gas generating agent 61 without being deactivated.

[0085] In this way, the transfer charge 59 and a large amount of heat particles generated by the transfer charge 59 flow into the combustion chamber 60, igniting and burning the gas generating agent 61 contained in the combustion chamber 60, generating a large amount of gas. The gas generated in the combustion chamber 60 passes through the inside of the filter 90, and in this process, heat is removed by the filter 90 and the gas is cooled, and slag contained in the gas is removed by the filter 90 and flows into the gap 28.

[0086] Then, as the pressure in the space inside the housing increases due to the combustion of gas generating agent 61, sealing tape 24 that has been closing gas outlet 23 provided in upper shell 20 ruptures, and gas is ejected to the outside of the housing through gas outlet 23. The ejected gas is introduced into the inside of an airbag provided adjacent to disc-shaped gas generator 100, and inflates and deploys the airbag.

[0087] Note that when the cup-shaped member 50 is made of iron or stainless steel, the strength is higher than when the cup-shaped member 50 is made of aluminum. Therefore, the cup-shaped member 50 does not rupture, deform, or melt in the initial stage of combustion of the enhancer charge 59. At this time, the internal pressure of the cup-shaped member 50 increases until a predetermined time has elapsed at which the fragile portion 55 of the cup-shaped member 50 ruptures, deforms, or melts. After the internal pressure reaches a certain level, the fragile portion 55 and the thin-walled portion 52a of the cup-shaped member 50 rupture, deform, or melt in sequence. Therefore, by using an iron-based metal material with high mechanical strength, such as iron or stainless steel, for the cup-shaped member 50, the mechanical strength can be increased to sufficiently promote the combustion of the enhancer charge 59 when the cup-shaped member 50 is split, thereby splitting the cup-shaped member 50. Such an improvement in the mechanical strength of the cup-shaped member 50 can be achieved by increasing the thickness, even when a metal with low strength, such as aluminum, is used. In this case, the thickness is preferably 0.4 mm or more and 1.5 mm or less, and more preferably 0.6 mm or more and 1.2 mm or less.

[0088] Hereinafter, with reference to FIG. 1, a mechanism by which transfer charge 59 can suitably control the transmission of flame energy in disk-shaped gas generator 100 in the present embodiment will be described.

[0089] In disk-shaped gas generator 100 configured as described above, activation of igniter 40 ignites transfer charge 59 inside transfer chamber 57, and first, fragile portion 55 of cup-shaped member 50 ruptures, deforms, or melts. Here, because cup-shaped member 50 ruptures, deforms, or melts from the portion serving as the starting point, there is no risk of rupture, deformation, or melting from side wall portion 52 where fragile portion 55 is not present, and top wall portion 51 ruptures, deforms, or melts after transfer charge 59 has sufficiently burned. Thereafter, top wall portion 51 ruptures along fragile portion 55, starting from ruptured, deformed, or melted fragile portion 55. After top wall portion 51 ruptures, the rupture reaches thin-walled portion 52a of side wall portion 52 and continues to rupture thin-walled portion 52a of side wall portion 52. The rupture stops at the connection between thin-walled portion 52a and thick-walled portion 52b.

[0090] In this way, the fragile portion 55 splits along the longitudinal direction, resulting in a petal-like split up to the connection between the thin-walled portion 52a and the thick-walled portion 52b. Therefore, the cup-shaped member 50 splits partway and then stops splitting, expanding over time toward the top plate portion 21. Since the size of the fracture in the cup-shaped member 50 remains stable, the thermal particles generated by the combustion of the transfer charge 59 flow more directionally toward the top plate portion 21. In other words, the flame flowing into the combustion chamber 60 is constricted between the cup-shaped member 50 and the top plate portion 21. Therefore, in the first stage of splitting, in which the fragile portion 55 ruptures, deforms, or melts and the non-fragile portion of the top wall portion 51 splits starting from the fragile portion 55, the gas generating agents 61 adjacent to the cup-shaped member 50 are not all ignited at once, and the flame spread of the gas generating agents 61 progresses mainly between the transfer chamber 57 and the top plate portion 21.

[0091] As the rupture, deformation, or melting of the top wall 51 of the cup-shaped member 50 progresses, the thin-walled portion 52a of the side wall 52 begins to split open in the second stage. The splitting of the side wall 52 proceeds along the longitudinal direction of the radially extending weakened portions 55 of the top wall 51. The thin-walled portion 52a splits downward in the axial direction of the side wall 52, but stops after splitting partway. Therefore, thermal particles generated by the combustion of the enhancer charge 59 flow into the combustion chamber 60 from the split portion. As a result, the fire spreads to the gas generating agent 61 between the thin-walled portion 52a and the filter 90, and then to the gas generating agent 61 between the thick-walled portion 52b and the filter 90.

[0092] Therefore, by providing the fragile portion 55, the non-fragile portion 56, the thin-walled portion 52a, and the thick-walled portion 52b in the cup-shaped member 50 and appropriately adjusting the positions and sizes of these fragile portion 55, the non-fragile portion 56, the thin-walled portion 52a, and the thick-walled portion 52b, it is possible to prevent the gas generant 61 from burning rapidly and intentionally delay the progress of the combustion, making it very easy to optimize the adjustment of the gas output according to specifications, such as maintaining the gas output for a predetermined period of time. Furthermore, in the early stages of rupture, deformation, or melting of the cup-shaped member 50, heat particles generated by the combustion of the transfer charge 59 flow toward the top plate portion 21, thereby mitigating the impact on the filter 90 and preventing damage thereto.

[0093] Furthermore, since the cushioning material 85 is arranged on the bottom plate portion 11 side, the combustion of the gas generating agent 61 between the top wall portion 51 and the top plate portion 21 proceeds smoothly immediately after the top wall portion 51 of the cup-shaped member 50 ruptures, deforms or melts, so there is no delay in gas output, the internal pressure inside the gas generator increases quickly, and furthermore, variations in the gas output characteristics can be prevented in advance.

[0094] Whether the fragile portion 55 and thin-walled portion 52a of the cup-shaped member 50 will rupture, deform, or melt due to the propagation of the thrust generated by the activation of the igniter 40 will depend on the mechanical strength (thickness, material, shape, etc.) of the cup-shaped member 50, the output of the igniter 40, the distance between the ignition portion 41 and the fragile portion 55 of the cup-shaped member 50, the density of the transfer charge 59 filled in the transfer chamber 57, etc.

[0095] Furthermore, it is preferable that the fragile portion 55 of the cup-shaped member 50 has a lower mechanical strength than the side wall portion 52 of the cup-shaped member 50. Possible methods for making the fragile portion 55 of the cup-shaped member 50 weaker than the side wall portion 52 of the cup-shaped member 50 include adjusting their thickness, using different materials for them, or devising their shapes.

[0096] With this configuration, it is relatively easy to cause the fragile portion 55 to rupture, deform, or melt before the thin-walled portion 52a of the cup-shaped member 50 ruptures, deforms, or melts. However, if the fragile portion 55 can be caused to rupture, deform, or melt before the thin-walled portion 52a of the cup-shaped member 50 ruptures, deforms, or melts, the fragile portion 55 and the thin-walled portion 52a of the side wall 52 of the cup-shaped member 50 may have approximately the same mechanical strength.

[0097] As explained above, according to disk-type gas generator 100 in the embodiment of the present invention described above, after top wall portion 51 of cup-shaped member 50 ruptures, deforms or melts, combustion of gas generating agent 61 between top wall portion 51 and ceiling plate portion 21 proceeds smoothly, making it possible to promote the combustion of gas generating agent 61 in combustion chamber 60. As a result, the time from the point in time when igniter 40 is activated to the point in time when gas starts to be ejected to the outside via gas ejection port 23 can be shortened compared to conventional cases. Furthermore, the size of the rupture of cup-shaped member 50 is stabilized (the rupture area becomes uniform) and enhancer charge 59 transfers flame to gas generating agent 61 without being affected by cushioning material 85, making it possible to provide disk-type gas generator 100 that can exhibit the desired gas output performance while reducing the filling amount of enhancer charge 59.

[0098] Furthermore, by adding the fragile portion 55 and thin-walled portion 52a to the cup-shaped member 50, although the amount of part processing increases, the amount of transfer charge 59 to be filled can be significantly reduced, and the time from when the igniter 40 is activated to when gas begins to be ejected to the outside through the gas outlet 23 can be shortened at low cost.

[0099] Furthermore, by reducing the amount of transfer charge 59 filled, the volume of cup-shaped member 50 can be made smaller than before, and therefore it is possible to optimize the volume of disk-type gas generator 100 and thereby reduce its weight.

[0100] Furthermore, since the gas temperature is lowered by reducing the amount of transfer charge 59, the cooling capacity of filter 90 may be reduced accordingly, which also makes it possible to reduce the weight of filter 90.

[0101] Although the embodiments of the present invention have been described above, they are merely illustrative examples and do not limit the present invention, and the specific configurations and the like can be appropriately modified in design. Furthermore, the actions and effects described in the embodiments of the invention are merely a list of the most preferable actions and effects resulting from the present invention, and the actions and effects of the present invention are not limited to those described in the embodiments of the present invention.

[0102] In the above embodiment, the cushion material 85 is disposed on the bottom plate portion 11 side, but the present invention is not limited to this. The cushion material 85 may be disposed at a position separated by a predetermined distance from the cup-shaped member 50, and may be disposed at a distance such that the transfer charge 59 is not deactivated before complete transfer of the transfer charge to the gas generant 61 when the igniter 40 is activated. For example, the cushion material 85 may be disposed at a position such that the transfer charge 59 is not adsorbed to the cushion material 85 before complete transfer of the transfer charge to the gas generant 61, or at a position far from the cup-shaped member 50 such that the transfer charge 59 is the last to reach the cushion material 85 within the combustion chamber 60.

[0103] In the above embodiment, the side wall 52 of the cup-shaped member 50 has been described as including the thin portion 52a and the thick portion 52b, but this is not limited thereto. The side wall 52 of the cup-shaped member 50 only needs to be configured to have a higher mechanical strength than the fragile portion 55 of the cup-shaped member 50, and for example, the thickness of the side wall 52 may be made constant by making the material of the side wall 52 and the material of the fragile portion 55 different.

[0104] A modification of the above embodiment will be described below with reference to Fig. 4. Note that disk-shaped gas generator 200 pertaining to the modification of the above embodiment differs from disk-shaped gas generator 100 pertaining to the above embodiment only in the configuration of the cup-shaped member. Note that components in this modification having the same last two digits as those in the above embodiment are the same components unless otherwise specified, and therefore description thereof will be omitted.

[0105] 4, in disk-shaped gas generator 200, cup-shaped member 250 has top wall portion 251, a cylindrical side wall portion 252 extending from the peripheral edge of top wall portion 251 toward bottom plate portion 211, and extended portion 253 extending radially outward from an open end which is the end of side wall portion 252 on the bottom plate portion 211 side. Extended portion 253 has a curved shape so as to follow the shape of the inner bottom surface of bottom plate portion 211 at the portion where protruding cylindrical portion 213 is provided and the vicinity thereof, and includes tip portion 254 extending in a flange-like shape at its radially outer portion. Top wall portion 251, side wall portion 252, extended portion 253, and tip portion 254 of cup-shaped member 250 have uniform thicknesses. The cup-shaped member 250 has a mechanical strength such that at least a part of the cup-shaped member 250 bursts, deforms, or melts when the igniter 240 is activated.

[0106] Suitable materials for the cup-shaped member 250 include metal members such as stainless steel, steel, aluminum, aluminum alloy, stainless steel, stainless steel alloy, etc., and resin members such as thermosetting resins typified by epoxy resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polyamide resin (e.g., nylon 6, nylon 66, etc.), polypropylene sulfide resin, polypropylene oxide resin, etc. In particular, aluminum alloys or iron-based metal materials such as stainless steel and steel, which have relatively higher mechanical strength than aluminum, are preferred.

[0107] In disk-type gas generator 200 configured in this manner, at least a part of either top wall portion 251 or side wall portion 252 of cup-shaped member 250 will burst, deform, or melt due to the thrust generated by the combustion of transfer charge 259 when igniter 240 is activated. Then, transfer charge 259 and a large amount of heat particles generated by transfer charge 259 flow into combustion chamber 260, reach gas generating agent 261 without being adsorbed to cushion material 285, and transfer the flame. In other words, since cushion material 285 is disposed on the bottom plate portion 211 side, combustion of gas generating agent 261 between top wall portion 251 and top plate portion 221 proceeds smoothly, so there is no delay in gas output, the internal pressure inside the gas generator increases quickly, and further, variations in gas output characteristics can be prevented in advance. Therefore, according to disk-shaped gas generator 200, it is possible to promote the combustion of gas generating agent 261 in combustion chamber 260, and to exhibit desired gas output performance.

[0108] (Verification test 1) As Example 1 and Example 2, disk-shaped gas generators having the same configuration as disk-shaped gas generator 200 described above were manufactured and subjected to a 60L tank test described below. Furthermore, as Example 3, a disk-shaped gas generator having the same configuration as disk-shaped gas generator 100 described above was manufactured and subjected to a similar 60L tank test. Note that in the disk-shaped gas generators according to Examples 1 to 3, the cushioning material is arranged on the bottom plate side of the combustion chamber (arranged below). Furthermore, in the disk-shaped gas generators according to Examples 1 to 3, the material of the cup-shaped member was made of an aluminum alloy.

[0109] As Comparative Example 1, a disc-shaped gas generator was manufactured that differed in configuration from the disc-shaped gas generator according to Example 1 only in that the cushioning material was arranged on the top plate side of the combustion chamber (upper arrangement), and a 60L tank test was performed. Similarly, as Comparative Example 2, a disc-shaped gas generator was manufactured that differed from the disc-shaped gas generator according to Example 2 only in the arrangement of the cushioning material, and a 60L tank test was performed. Note that FIG. 5 is a schematic cross-sectional view of disc-shaped gas generator 300 having the same configuration as Comparative Example 1 and Comparative Example 2. Furthermore, the material of the cup-shaped member according to Comparative Example 1 and Comparative Example 2 was made of an aluminum alloy.

[0110] Furthermore, as Comparative Example 3, a disc-shaped gas generator was manufactured which differed in configuration from the disc-shaped gas generator according to Example 3 only in that the cushioning material was arranged on the top plate side of the combustion chamber (upper arrangement), and a 60L tank test was carried out. Note that Fig. 6 is a schematic cross-sectional view of disc-shaped gas generator 400 having the same configuration as Comparative Example 3. Furthermore, the material of the cup-shaped member according to Comparative Example 3 was made of an aluminum alloy.

[0111] In Verification Test 1, the 60 L tank test was a test in which the disk-shaped gas generators according to Examples 1 to 3 and Comparative Examples 1 to 3 were individually placed in a sealed tank with a volume of 60 L, and these were operated at room temperature (RT), and the increase in the pressure inside the tank was measured over time from the time the igniter was activated until 100 ms.

[0112] Figure 7 shows the results of Verification Test 1. In Figure 7, t1 is the time until gas output is detected, Pt20 is the tank internal pressure 20 ms after the igniter is activated, Pt40 is the tank internal pressure 40 ms after the igniter is activated, and Pmax is the maximum tank internal pressure. The same applies to Figures 8 and 9 below.

[0113] 7 shows that the disk-shaped gas generator according to Example 1 had similar t1 compared to the disk-shaped gas generator according to Comparative Example 1, but all of Pt20, Pt40 and Pmax were larger, enabling high gas output performance to be exhibited. Furthermore, it was found that the disk-shaped gas generator according to Example 2, in which the amount of transfer charge was reduced compared to Example 1 (weight reduction was achieved), was able to exhibit high gas output performance at a relatively early stage from the time the igniter was activated, compared to the disk-shaped gas generator according to Comparative Example 2. It was also found that the disk-shaped gas generator according to Example 3, which was similarly designed to be lighter, was able to exhibit high gas output performance at a relatively early stage from the time the igniter was activated, compared to the disk-shaped gas generator according to Comparative Example 3. Therefore, it was found that the gas output performance was improved in each of the disk-shaped gas generators according to Examples 1 to 3, in which the cushioning material was arranged lower, when compared in order with Comparative Examples 1 to 3, in which the cushioning material was arranged upper.

[0114] Furthermore, in the disk-shaped gas generator according to Example 3, t1 is shorter and both Pt20 and Pt40 are larger than in the disk-shaped gas generator according to Example 2, and it was found that preferable gas output performance can be stably exhibited while reducing the amount of transfer charge. Therefore, it was confirmed that a disk-shaped gas generator having the same configuration as above-mentioned disk-shaped gas generator 100 of the present invention can be made lighter in weight and can stably exhibit excellent gas output performance.

[0115] (Verification test 2) Next, a disc-shaped gas generator having the same configuration as disc-shaped gas generator 400 shown in FIG. 6 was manufactured, and verification test 2 was conducted to determine what changes would occur in a 60 L tank test, which will be described later, depending on whether or not a cushioning material was present.

[0116] Here, in the disk-shaped gas generator according to Comparative Example 4, a cushion material is arranged on the top plate side of the combustion chamber (arranged above). Moreover, in the disk-shaped gas generator according to Comparative Example 5, a cushion material is not provided. Moreover, the material of the cup-shaped member according to Comparative Example 4 and Comparative Example 5 was made of an aluminum alloy. Note that the other conditions in each disk-shaped gas generator were the same except for the presence or absence of a cushion material.

[0117] In Verification Test 2, the 60L tank test was a test in which the disk-type gas generators according to Comparative Examples 4 and 5 were individually placed in a sealed tank with a volume of 60L, and these were operated at -40°C (LT) to measure the increase in tank internal pressure over time from the time the igniter was activated up to 100 ms. The results of Verification Test 2 are shown in Figure 8.

[0118] 8 shows that in the disk-shaped gas generator according to comparative example 4, t1 was longer and Pt20, Pt40 and Pmax were all smaller than in the disk-shaped gas generator according to comparative example 5. Therefore, it was confirmed that in the disk-shaped gas generator according to comparative example 4 in which the cushion material was arranged on top, gas output performance was reduced due to the influence of the cushion material compared to the disk-shaped gas generator according to comparative example 5.

[0119] (Verification test 3) Next, a disk-shaped gas generator having the same configuration as disk-shaped gas generator 100 shown in Figure 1 was manufactured, and verification test 3 was conducted to determine what changes would occur in the 60L tank test described below by changing the height (distance from the upper support member) of the surface of the gas generating agent (the top position of the gas generating agent) placed on the top of the cup-shaped member.

[0120] Here, in the disk-shaped gas generator according to Example 4, the height of the charge surface of the gas generating agent was 3 mm. Furthermore, in the disk-shaped gas generator according to Example 5, the height of the charge surface of the gas generating agent was 5 mm. Furthermore, in the disk-shaped gas generator according to Example 6, the height of the charge surface of the gas generating agent was 7 mm. Note that the higher the height of the charge surface of the gas generating agent, the greater the amount of gas generating agent disposed between the top wall and ceiling plate of the cup-shaped member. Furthermore, the material of the cup-shaped member according to Examples 4 to 6 was made of an aluminum alloy. Note that the other conditions other than the height of the charge surface of the gas generating agent were the same in each disk-shaped gas generator.

[0121] In Verification Test 3, the 60L tank test was a test in which the disk-shaped gas generators according to Examples 4 to 6 were individually placed in a sealed tank with a volume of 60L, and these were operated at -40°C (LT) to measure the increase in tank internal pressure over time from the time the igniter was activated until 100 ms. The results of Verification Test 3 are shown in Figure 9.

[0122] 9 shows that the disk-shaped gas generators according to Examples 5 and 6 achieve higher gas output performance at a relatively early stage from the time the igniter is activated than the disk-shaped gas generator according to Example 4. Therefore, it was found that in a disk-shaped gas generator having the same configuration as above-mentioned disk-shaped gas generator 100 of the present invention, desirable gas output performance can be stably exhibited so long as the height of the charge surface of the gas generating agent is 5 mm or more.

[0123] (Verification Test 4) Next, a disk-shaped gas generator (Example 7) having the same configuration as gas generator 500 shown in Fig. 10 was manufactured, and verification test 4 was conducted to determine what changes would occur in the above-mentioned 60 L tank test depending on the presence or absence of a lower support member and the position of the cushioning material. The results of verification test 4 are shown in Fig. 11. Fig. 11 also shows the results of comparative example 3 and example 3 above.

[0124] Here, gas generator 500 shown in FIG. 10 is a disk-shaped gas generator according to a modification of the above-described embodiment, and differs from the above-described embodiment in the following points: (1) it does not have a lower support member, and (2) on the side of lower shell 510, disk-ring-shaped cushion material 585 is disposed within housing 510 so that the inside of cushion material 585 abuts against the outer wall and tip portion 554 of the lower part of cup-shaped member 550, and so that the outside of cushion material 585 abuts against the inner wall of the lower part of filter 590. Note that components in this modification whose last two digits match those in the above-described embodiment are the same components unless otherwise specified, and therefore description thereof will be omitted. According to this gas generator 500, the same effects as those of the above-described embodiment can be achieved. Furthermore, cushion material 585 allows filter 590 to be positioned when assembling gas generator 500. Furthermore, by pressing down tip 554 (the portion forming the flange) of cup-shaped member 550 with cushion material 585, it is possible to prevent cup-shaped member 550 from coming off inner covering part 531 before cup-shaped member 550 is torn open. In addition, cushion material 585 remains unburned during operation, and therefore it is possible to prevent combustion residue from flowing out from between the lower end of filter 590 and the inner wall of lower shell 510.

[0125] 11 shows that the disk-shaped gas generator according to Example 7 is able to exhibit high gas output performance at a relatively early stage from the time the igniter is activated, compared to the disk-shaped gas generator according to Comparative Example 3. The result of FIG. 11 also shows that the disk-shaped gas generator according to Example 7 does not have a lower support member, but is able to exhibit gas output performance similar to that of the disk-shaped gas generator according to Example 3 which has said lower support member. In other words, the result of this verification test shows that the disk-shaped gas generator according to Example 7 can achieve the same effects as Example 3, while allowing for a reduction in the number of parts and weight compared to the disk-shaped gas generator according to Example 3. [Explanation of symbols]

[0126] 10, 210, 310, 410, 510 Lower side shell 11, 211, 311, 411, 511 Bottom plate part 12, 212, 312, 412, 512 Peripheral wall part 13, 213, 313, 413, 513 Projected tube part 14, 214, 314, 414, 514 recessed part 15, 215, 315, 415, 515 openings 20, 220, 320, 420, 520 Upper side shell 21, 221, 321, 421, 521 Top plate 22, 222, 322, 422, 522 Peripheral wall part 23, 223, 323, 423, 523 Gas outlet 24, 224, 324, 424, 524 sealing tape 28, 228, 328, 428, 528 Gap 30, 230, 330, 430, 530 Holding part 31, 231, 331, 431, 531 Inner coating 32, 232, 332, 432, 532 Outer covering part 33, 233, 333, 433, 533 connection part 34, 234, 334, 434, 534 female connector part 40, 240, 340, 440, 540 igniter 41, 241, 341, 441, 541 Ignition section 42, 242, 342, 442, 542 terminal pins 50, 250, 350, 450, 550 Cup-shaped member 51, 251, 351, 451, 551 Top wall 52, 252, 352, 452, 552 Side wall 52a, 452a, 552a Thin wall part 52b, 452b, 552b Thick wall part 53, 253, 353, 453, 553 Extension section 54, 254, 354, 454, 554 Tip 55, 455, 555 Weak parts 56, 456, 556 Non-weakened parts 57, 257, 357, 457, 557 Fire transmission room 59, 259, 359, 459, 559 Transfer charges 60, 260, 360, 460, 560 combustion chamber 61, 261, 361, 461, 561 Gas Generators 70, 270, 370, 470 Lower support member 71, 81, 271, 281, 371, 381, 471, 481, 581 base 72, 82, 272, 282, 372, 382, ​​472, 482, 582 Contact part 73, 273, 373, 473 Standing section 80, 280, 380, 480, 580 Upper support member 85, 285, 385, 485, 585 cushioning material 90, 290, 390, 490, 590 filters 100, 200, 300, 400, 500 Disc type gas generator

Claims

[Claim 1] a short cylindrical housing having a combustion chamber therein and containing a gas generating agent, the housing being composed of a cylindrical peripheral wall portion provided with a gas ejection port, a top plate portion closing one axial end of the peripheral wall portion, and a bottom plate portion closing the other axial end of the peripheral wall portion; and an igniter including an ignition portion assembled to the bottom plate portion and containing an ignition charge that ignites when activated; A cup-shaped member made of a single cylindrical member with a bottom, which includes a transfer chamber containing a transfer charge therein and is arranged to protrude toward the combustion chamber so that the internal space of the transfer chamber faces the ignition part; a cushioning material disposed on the bottom plate portion side and supporting the gas generating agent from the bottom plate portion side; Equipped with An approximately disk-shaped upper support member is disposed at an end of the combustion chamber that is located on the top plate side, the gas generating agent disposed on the top plate portion side is disposed between the cup-shaped member and the upper support member so as to be in contact with the upper support member, The cup-shaped member includes a top wall portion having a thin-walled weak portion at least in a portion thereof, and a side wall portion of the cup-shaped member that separates the transfer chamber and the combustion chamber and has a mechanical strength higher than that of the weak portion, the side wall portion includes a thin portion provided on the top wall portion side and a thick portion extending from the thin portion along the axial direction to a side opposite the top wall portion, the fragile portion is disposed opposite the ignition portion and has a mechanical strength that causes the cup-shaped member to rupture, deform, or melt before the side wall portion does upon activation of the igniter, the thin-walled portion has a mechanical strength such that it will rupture, deform, or melt when rupture, deformation, or melting in the fragile portion progresses to the thin-walled portion; Gas generator.

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