Gas generator

Abstract

To provide a gas generator which is easily assembled and can be manufactured at low cost while having an antirust effect.SOLUTION: A gas generator has a short-length, substantially cylindrical housing with one end and the other end in an axial direction being closed. In a storage space provided inside the housing, a holding part 30, an igniter 40, a cup-shaped member 50, a transfer charge 59, a gas generating agent 61, a lower side support member 70, an upper side support member 80, a cushioning material 85 and a filter 90 are housed as inner components. A combustion chamber 60 in which, inter alia, the gas generating agent 61 among the inner components is housed is positioned in the storage space provided inside the housing. The surface of the housing is covered with a film 16 together with a body 17a of a male connector part 17 and a part of a wiring 18 connected to the body 17a.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gas generator to be incorporated into an occupant protection device for protecting an occupant in the event of a collision of a vehicle or the like, and a method for manufacturing the gas generator. [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 gas generator having an igniter assembly in which the surface of a metal igniter collar is deformed into a convex shape relative to a concave portion of a resin part, and the convex portion is fitted into the concave portion to form an integrated unit. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-062685 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0008] In the gas generator of Patent Document 1, inexpensive iron can be used because rust prevention treatment is not required for the surface where the igniter collar and the resin part come into contact. However, the processing and assembly of the igniter collar are complicated, and the manufacturing cost tends to be relatively high.

[0009] The present invention has been made in view of the above circumstances, and has an object to provide a gas generator that has an anti-rust effect, can be easily assembled, and can reduce manufacturing costs. [Means for solving the problem]

[0010] (1) A gas generator of the present invention is characterized in that it comprises a cylindrical housing having a combustion chamber therein containing a gas generating agent, the cylindrical housing being composed of a cylindrical peripheral wall portion provided with a gas outlet, one end portion closing one axial end of the peripheral wall portion, and another end portion closing the other axial end of the peripheral wall portion, an igniter assembled to the other end portion and including an ignition portion containing an ignition charge that ignites when activated, a connector pocket assembled to the other end portion and capable of receiving a connector portion that is electrically conductive with the igniter, and a film covering the surface of the housing.

[0011] (2) In the gas generator of (1) above, it is preferable that the connector portion having wiring electrically connected to an external device is attached to the connector pocket portion, and that the film covers at least the surface of the body of the connector portion together with the surface of the housing.

[0012] (3) From another viewpoint, in the gas generator of (1) above, the film may not cover at least the inside of the connector pocket portion of the housing. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a gas generator that has an anti-rust effect, can be easily assembled, and can reduce manufacturing costs. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view of a disk-type gas generator according to a first embodiment of the present invention. [Figure 2] 2A and 2B are schematic diagrams of the disk-type gas generator of FIG. 1 as viewed from the lower shell side, where FIG. 2A shows the state before being covered with a film, and FIG. 2B shows the state after being covered with a film. [Figure 3] FIG. 5 is a schematic cross-sectional view of a disk-type gas generator according to a second embodiment of the present invention. [Figure 4] 4A and 4B are schematic diagrams of the disk-shaped gas generator of FIG. 3 as viewed from the lower shell side, where FIG. 4A shows the state before being covered with a film, and FIG. 4B shows the state after being covered with a film. DETAILED DESCRIPTION OF THE INVENTION

[0015] First Embodiment A first embodiment of the present invention will be described in detail below with reference to the drawings. The embodiment shown below is a disc-type gas generator that is suitably incorporated into an airbag device mounted on the steering wheel of an automobile or the like.

[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 and the other axial ends closed, and an accommodation space provided inside this housing accommodates internal components such as retaining portion 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, the accommodation space provided inside the housing is located combustion chamber 60 which primarily accommodates gas generating agent 61 of the above-mentioned internal components. Also, the surface of the housing is covered with film 16, together with main body 17a of male connector portion 17, which will be described later, and a portion of wiring 18 connected to main body 17a.

[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, a peripheral wall portion 22, and a protrusion 25. The protrusion 25 has a through-hole 19 for fixing to an airbag module or the like. The through-hole 19 is not covered by the film 16 described below.

[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 a female connector portion 34 (an example of a connector pocket portion) 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, which is a connector pocket, is formed in the portion of the outer covering portion 32 of the holding portion 30 facing the outside. This female connector portion 34 is a portion for receiving a male connector portion 17 of a harness for connecting the igniter 40 to a control unit (not shown), and is located in a recess portion 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. The main body 17a of the male connector portion 17 is inserted into the female connector portion 34, thereby establishing electrical continuity between the core wire (wire 18) of the harness and the terminal pin 42.

[0036] The film 16 has a waterproof function and covers the housing (the lower shell 10 and the upper shell 20), the outer surface of the main body 17a of the male connector portion 17, and a portion of the wiring 18 connected to the main body 17a (for example, the wiring 18 other than the portion required for wiring) in a waterproof state. Note that the film 16 does not cover the through-hole 19 provided in the upper shell 20. Also, although the gas outlet 23 is covered in this embodiment, it does not have to be covered.

[0037] Furthermore, film 16 is a heat-shrinkable film made of, for example, polyolefin, vinyl chloride, or polypropylene, and is what is known as a shrink film. For example, a method of forming film 16 is as follows. First, gas generator 100A before film 16 is formed (see FIG. 2(a)), and a film bag before film 16 is formed are prepared. Gas generator 100A is entirely covered with the film bag, and hot air is applied to the surface of the shrink film bag to cause it to shrink, and the film is brought into close contact with main body 17a of male connector portion 17, a portion of wiring 18 connected to main body 17a, and the entire surface of gas generator 100A other than main body 17a and a portion of wiring 18 (see the shaded area (portion showing film 16) in FIG. 2(b)). This completes waterproofed disk-shaped gas generator 100.

[0038] As a variation of the above-described injection molding, for example, the above-described injection molding may 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 an adhesive to a predetermined position on the bottom plate portion 11 in advance and then curing the adhesive, for example.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] The filter 90 also 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.

[0061] 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.

[0062] 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.

[0063] A lower support member 70 is disposed near the end of the combustion chamber 60 that is located on the bottom plate portion 11 side. The lower support member 70 has an annular shape and is disposed substantially between the filter 90 and the bottom plate portion 11 so as to cover the boundary between the filter 90 and the bottom plate portion 11.

[0064] 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.

[0065] 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).

[0066] 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.

[0067] 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.

[0068] 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).

[0069] A circular plate-shaped cushion material 85 is arranged inside the base 81 of the upper support member 80 so as to come into contact with the gas generating agent 61 accommodated 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 represented by chloroprene and EPDM, or the like.

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

[0071] Next, the operation of disk-shaped gas generator 100 in the present embodiment will be described.

[0072] 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, igniter 40 is activated by current flow from a control unit (an example of an external device) separately provided in the vehicle via wiring 18 and male connector portion 17. Transfer charge 59 accommodated in transfer chamber 57 is ignited by a flame generated by the activation of igniter 40, and begins combustion.

[0073] At this time, immediately after the igniter 40 is activated, the ignition charge loaded in the ignition section 41 burns rapidly, 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.

[0074] Subsequently, the thrust reaches the top wall 51 of the cup-shaped member 50, causing the cup-shaped member 50, which is made of a fragile material, to burst, deform, or melt. This burst, deformation, or melting of the cup-shaped member 50 occurs later than the ignition of the transfer charge 59 by the heat particles generated by the combustion of the ignition charge. 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 inside the cup-shaped member 50.

[0075] Therefore, in a short time, the transfer charge 59 located farther from the igniter 40 is also ignited by the thermal particles 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 cup-shaped member 50 bursts, deforms, or melts in a short time, and a large amount of thermal particles generated by the combustion of the transfer charge 59 flows into the combustion chamber 60 early.

[0076] 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.

[0077] 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.

[0078] In addition, 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 cup-shaped member 50 ruptures, deforms, or melts. Then, once the internal pressure reaches a certain level, the cup-shaped member 50 ruptures, deforms, or melts. 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 ruptured, thereby rupturing the cup-shaped member 50. Such an improvement in the mechanical strength of the cup-shaped member 50 can be achieved by increasing its thickness, even when a metal with low strength, such as aluminum, is used. In this case, the thickness is preferably 0.4 mm to 1.5 mm, and more preferably 0.6 mm to 1.2 mm.

[0079] As described above, it is possible to provide disc-shaped gas generator 100 that has an anti-rust effect, can be easily assembled, and can reduce manufacturing costs.

[0080] Specifically, for example, because disc-shaped gas generator 100 is covered with waterproof film 16, rust on the housing can be suppressed, and even if male connector portion 17 is not a waterproof connector portion, disc-shaped gas generator 100 can be made waterproof. Furthermore, because coating treatments including black dyeing or painting are not required on the housing surface, there is no need to select a housing material that takes such processing or coating into consideration. Furthermore, because there is no need for ventilation and exhaust equipment for the coating solution that is required in the case of painting, disc-shaped gas generator 100 can be made to be friendly to the human body and the environment.

[0081] Second Embodiment Next, a second embodiment of the present invention will be described in detail with reference to Figures 3 and 4. Hereinafter, the second embodiment will be described. However, in this embodiment, reference numerals having the same last two digits as those in the first embodiment are similar, and therefore their description may be omitted. Furthermore, parts that are not particularly described are similar to those in the first embodiment, and therefore their description may be omitted.

[0082] Disk-type gas generator 200 differs from the first embodiment in that it is not provided with a male connector portion, and that holding portion 130 and the inside of holding portion 130 on the housing surface are not covered with film 116.

[0083] In disk-shaped gas generator 200, retaining portion 130 and the inside of retaining portion 130 on the housing surface are not covered by film 116 in order to facilitate easy assembly when assembling male connector portion (not shown) to female connector portion 134 after film 116 has been formed (without tearing film 116 that covers retaining portion 130).

[0084] For example, a method of forming film 116 is as follows. First, disc-shaped gas generator 200A before film 116 is formed (see FIG. 4(a)), and a film bag before film 116 is formed are prepared. Disc-shaped gas generator 200A is covered with the film bag so as not to cover holding section 130 and the inside of holding section 130, and hot air is blown onto the surface of the film bag to cause it to shrink and come into close contact with the entire surface of disc-shaped gas generator 200A except for holding section 130 and the inside of holding section 130 (see the shaded area (part showing film 116) in FIG. 4(b)). This completes waterproofed disc-shaped gas generator 200.

[0085] According to disk-shaped gas generator 200, the same effects as those of the first embodiment can be achieved.

[0086] 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.

[0087] In the first and second embodiments described above, the case where the gas generator is a disk-type gas generator has been described, but the present invention is not limited to this. For example, the gas generator may be a cylinder-type gas generator provided with a long, substantially cylindrical housing having one axial end closed by a closing member (an example of one end of the housing) and the other end closed by a holder (an example of the other end of the housing) that holds an igniter.

[0088] In the second embodiment, the holding portion 130 and the inside of the holding portion 130 are not covered with the film 116, but this is not limiting. For example, the boundary portion between the holding portion 130 and the lower shell 111 may also be covered with the film 116. [Explanation of symbols]

[0089] 10, 110 Lower side shell 11, 111 Bottom plate part 12, 22, 112, 122 Peripheral wall part 13, 113 Projected cylinder part 14, 114 recess 15, 115 opening 16, 116 film 17, 117 Male connector part 18, 118 Wiring 19, 119 through holes 20, 120 Upper side shell 21, 121 Top plate 23, 123 Gas outlet 24, 124 sealing tape 25, 125 protrusion 28, 128 Gap 30, 130 Holding part 31, 131 Inner coating 32, 132 Outer covering part 33, 133 connection part 34, 134 Female connector part 40, 140 igniter 41, 141 Ignition part 42, 142 terminal pins 50, 150 Cup-shaped member 51, 151 Top wall 52, 152 Side wall 53, 153 Extension section 54, 154 Tip 57, 157 Fire transmission room 59, 159 Transfer powder 60, 160 combustion chamber 61, 161 Gas generator 70, 170 Lower support member 71, 81, 171, 181 base 72, 82, 172, 182 Contact part 73, 173 erection section 80, 180 Upper support member 85, 185 cushioning material 90, 190 filters 100, 100A, 200, 200A disc type gas generator

Claims

1. a cylindrical housing having a combustion chamber therein and containing a gas generating agent, the cylindrical housing including a cylindrical peripheral wall portion provided with a gas outlet, one end portion closing one axial end of the peripheral wall portion, and another end portion closing the other axial end of the peripheral wall portion; an igniter assembled to the other end and including an ignition part containing an ignition charge that ignites when activated; a connector pocket portion assembled to the other end portion and capable of receiving a connector portion that can be electrically connected to the igniter; a film covering a surface of the housing; A gas generator comprising:

2. The connector portion, which has wiring electrically connected to an external device, is attached to the connector pocket portion; 2. The gas generator according to claim 1, wherein the film covers the surface of the housing as well as at least the surface of the body of the connector portion.

3. 2. The gas generator according to claim 1, wherein the film does not cover at least the inside of the connector pocket portion of the housing.

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