Gas generator

Abstract

To reduce manufacturing costs and inhibit occurrence of connection failure of a ground terminal during manufacturing in a gas generator in which the ground terminal is embedded in a resin holding part holding an igniter.SOLUTION: A gas generator 1A includes: housings 10, 20; and a holding part 30 which holds an igniter 40. A protruding cylinder part 13 is provided at a bottom plate part 11 of the housings 10, 20. The holding part 30 includes an outer cover part 32 adhered to an outer surface of the protruding cylinder part 13. The outer cover part 32 is provided with a female type connector part 34. A ground terminal 50 includes: a contact part 51 which contacts with a portion which is located around the protruding cylinder part 13 of the outer surface of the bottom wall part 11; an exposed part 52 facing an insertion space of the female type connector part 34; and a connection part 53 which connects the contact part 51 with the exposed part 52. The ground terminal 50 is held embedded in the outer cover part 32 in a state that the connection part 53 is covered with the outer cover part 32 and the contact part 51 is exposed to the outside.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a gas generator to be incorporated in an airbag device as an occupant protection device equipped in an automobile or the like. [Background technology]

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

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

[0004] Here, a gas generator is generally provided with a connector section for connection with the above-mentioned control unit. Furthermore, this connector section may be provided with a ground terminal from the viewpoint of preventing malfunction due to static electricity caused by electric charge accumulated in the gas generator. An example of a gas generator having such a ground terminal provided in a connector section is disclosed in Japanese Patent Laid-Open Publication No. 2017-36043 (Patent Document 1).

[0005] In the gas generator disclosed in Patent Document 1, an igniter is fixed to a housing by a retaining portion made of a molded resin portion, and this retaining portion is further provided with a female connector portion as the connector portion described above. The above-mentioned ground terminal is composed of a tubular conductive member embedded in the retaining portion made of molded resin, with the outer surface of this conductive member abutting the housing and the inner circumferential surface of this conductive member being exposed inside the female connector portion. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-36043 Summary of the Invention [Problem to be solved by the invention]

[0007] However, when the structure disclosed in Patent Document 1 is adopted, it is necessary to accurately position the surface of the conductive member that should be exposed inside the female connector portion (i.e., the inner surface of the cylindrical conductive member), ensure that the outer surface of the conductive member is securely abutting against the housing, and then injection mold the holding portion in this state. This requires very strict control of the external dimensions of the conductive member, and even the external dimensions of the housing at the portion that abuts against the conductive member.

[0008] In other words, even a slight variation in these external dimensions can cause molten resin to flow between the conductive member and the housing during resin molding of the holding portion, and this flowing resin can hinder contact at that point, resulting in poor connection of the ground terminal.

[0009] Therefore, the present invention has been made in consideration of the above-mentioned problems, and its object is to reduce manufacturing costs and suppress the occurrence of poor connection of the ground terminal during manufacturing in a gas generator in which the ground terminal is embedded in a resin holding part that holds an igniter. [Means for solving the problem]

[0010] A gas generator according to the present invention includes a housing, an igniter, and a holding portion. The housing has a combustion chamber therein that accommodates a gas generating agent, and includes a top plate portion, a bottom plate portion, and a cylindrical peripheral wall portion provided with a gas outlet. The igniter includes an ignition portion loaded with an ignition charge for combusting the gas generating agent, and a terminal pin connected to the ignition portion. The holding portion is provided on the bottom plate portion and is made of a resin portion that holds the igniter. The bottom plate portion is provided with a protruding cylindrical portion that has a bottom. The protruding cylindrical portion includes a cylindrical portion that protrudes toward the top plate portion and a shelf portion located at an end of the cylindrical portion on the top plate portion side, and the shelf portion is provided with an opening. The igniter is held by the holding portion with the ignition portion located closer to the top plate portion than the shelf portion, and the terminal pin inserted through the opening. The holding portion includes a closing portion that closes the opening, an inner covering portion that is fixed to the ignition portion and is fixed to the inner surface of the bottom plate portion in the portion corresponding to the shelf portion, and an outer covering portion that is fixed to the outer surface of the bottom plate portion in the portion corresponding to the shelf portion and to the outer surface of the bottom plate portion in the portion corresponding to the cylindrical portion.

[0011] In the gas generator according to the present invention, the outer covering defines a recessed insertion space exposed to the outside, and is provided with a female connector portion with the terminal pin exposed in the insertion space. The outer covering is further provided with a ground terminal made of a conductive member. The ground terminal includes a contact portion that contacts the outer surface of the bottom plate portion at a portion located around the protruding tubular portion, an exposed portion that faces the insertion space, and a connecting portion that connects the contact portion and the exposed portion. In the gas generator according to the present invention, the ground terminal is embedded and held by the outer covering, with the connecting portion covered by the outer covering and the abutting portion exposed to the outside. [Effects of the Invention]

[0012] According to the present invention, in a gas generator in which a ground terminal is embedded in a resin holding portion that holds an igniter, it is possible to reduce manufacturing costs while suppressing the occurrence of poor connection of the ground terminal during manufacturing. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic view of a disk-type gas generator according to an embodiment. [Figure 2] 2 is an enlarged view of the vicinity of a female connector portion of the disk-type gas generator shown in FIG. 1. FIG. [Figure 3] FIG. 2 is a perspective view of a ground terminal provided in the disk-type gas generator shown in FIG. [Figure 4] 2A to 2C are schematic cross-sectional views showing a manufacturing process of the disk-shaped gas generator shown in FIG. 1. [Figure 5] 2A to 2C are schematic cross-sectional views showing a manufacturing process of the disk-shaped gas generator shown in FIG. 1. [Figure 6] 2A to 2C are schematic cross-sectional views showing a manufacturing process of the disk-shaped gas generator shown in FIG. 1. [Figure 7] FIG. 10 is an enlarged view of the vicinity of a female connector portion of a disk-shaped gas generator according to a modified example. [Figure 8] FIG. 8 is a perspective view of a ground terminal provided in the disk-type gas generator shown in FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0014] 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.

[0015] (Embodiment) Fig. 1 is a schematic diagram of a disk-type gas generator according to an embodiment. First, with reference to Fig. 1, the configuration of disk-type gas generator 1 according to the present embodiment will be described.

[0016] As shown in Fig. 1, disk-shaped gas generator 1 has a short, substantially cylindrical housing whose one and other axial ends are closed. An accommodating space provided inside the housing accommodates internal components such as retaining portion 30, igniter 40, cup-shaped member 60, transfer charge 66, gas generating agent 71, lower support member 72, upper support member 73, cushion material 74, and filter 80. A combustion chamber 70, which mainly accommodates gas generating agent 71 out of the above-mentioned internal components, is located in the accommodating space provided inside the housing.

[0017] 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-formed 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 are used, which do not break or otherwise damage even when a tensile stress of 440 MPa or more but 780 MPa or less is applied.

[0018] Lower shell 10 and upper shell 20 are each formed in a generally cylindrical shape with a bottom, and are combined and joined together so that their open surfaces face each other to form a housing. Lower shell 10 has a bottom plate portion 11 and a side plate portion 12. Upper shell 20 has a top plate portion 21, a side plate portion 22, and a flange portion 23. Flange portion 23 is a portion for fixing disc-shaped gas generator 1 to an external member.

[0019] The upper end of the side plate portion 12 of the lower shell 10 is inserted into the lower end of the side plate portion 22 of the upper shell 20 and press-fitted. Furthermore, the side plate portion 12 of the lower shell 10 and the side plate portion 22 of the upper shell 20 are joined at or near their abutting portion, thereby fixing the lower shell 10 and the upper shell 20 together. 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.

[0020] As a result, the portion of the peripheral wall of the housing closer to the bottom plate 11 is formed by the side plate 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 side plate 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.

[0021] 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. The protruding cylindrical portion 13 is a portion to which the igniter 40 is fixed via a holding portion 30. The protruding cylindrical portion 13 is formed in a cylindrical shape with a bottom, and has a cylindrical portion 14 and a shelf portion 15 that is located at the end of the cylindrical portion 14 on the top plate portion 21 side.

[0022] An opening 16 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 in shelf portion 15. Opening 16 is a portion through which a pair of terminal pins 42 of igniter 40 are inserted.

[0023] A recess 17 defined by the protruding tubular portion 13 is formed in the center of the bottom plate portion 11 of the lower shell 10. The recess 17 is a portion that becomes a space for providing the female connector portion 34 in the holding portion 30.

[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] Ignition unit 41 includes a cup-shaped squib cup and a base that closes the open end of the squib cup and that holds a pair of terminal pins 42 inserted therethrough. A resistor (bridge wire) is attached to ignition unit 41 so as 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] The resistor is generally made of nichrome wire, and the ignition charge is generally made of ZPP (zirconium potassium perchlorate), ZWPP (zirconium tungsten potassium perchlorate), lead tricinate, etc. The squib cup and base 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 milliseconds or less when nichrome wire is used for the resistor.

[0028] Igniter 40 is assembled to bottom plate 11 in a state where it is inserted from the inside of lower shell 10 so that ignition portion 41 is located closer to top plate 21 than shelf plate 15 and terminal pin 42 is inserted into opening 16 provided in shelf plate 15. More 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 this holding portion 30.

[0029] 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.

[0030] 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 closing portion 33 that connects the inner covering portion 31 and the outer covering portion 32.

[0031] More specifically, the holding portion 30 is provided so as to cover the protruding tubular portion 13 provided on the bottom plate portion 11, the inner covering portion 31 is positioned so as to cover the inner surface of the shelf portion 15 of the protruding tubular portion 13, and the outer covering portion 32 is positioned so as to cover the outer surface of the shelf portion 15 of the protruding tubular portion 13 and the outer surface of the tubular portion 14. In addition, the closing portion 33 closes the opening 16 provided in the shelf portion 15 of the protruding tubular portion 13.

[0032] The retaining portion 30 is fixed to the bottom plate portion 11 on the surface of each of the inner covering portion 31, the outer covering portion 32, and the closing portion 33 facing 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 16 is completely filled with terminal pin 42 and holding portion 30, and the sealing of this portion ensures airtightness of the interior space of the housing. Since opening 16 is formed in an asymmetrical shape in a plan view as described above, by filling opening 16 with closing portion 33, opening 16 and closing 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 the outside. 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 within a recess 17 provided in the bottom plate portion 11 of the lower shell 10.

[0035] More specifically, female connector portion 34 is provided on the outer covering portion 32 at the portion exposed to the outside so as to define a recessed insertion space therein, and a portion of terminal pin 42 of igniter 40 near the lower end is exposed inside this recessed insertion space. A male connector of a harness is inserted into this recessed insertion space of female connector portion 34, thereby establishing electrical continuity between the core wire of the harness and terminal pin 42.

[0036] Furthermore, a ground terminal 50 is embedded in outer covering portion 32, and a portion of ground terminal 50 is positioned so as to face the above-mentioned concave insertion space. Ground terminal 50 is provided in female connector portion 34 from the perspective of preventing malfunction due to static electricity caused by electric charge accumulated in disc-type gas generator 1, and details thereof will be described later.

[0037] Here, an adhesive layer may be provided in advance on the surface of the bottom plate 11 in the portion that will be covered by the retaining portion 30 prior to injection molding of the retaining portion 30. In this way, the hardened adhesive layer is positioned between the bottom plate 11 and the retaining portion 30, making it possible to more firmly fix the retaining portion 30, which is made of a resin molded portion, to the bottom plate 11. Therefore, if the adhesive layer is provided in a ring shape along the circumferential direction so as to surround the opening 16 provided in the shelf portion 15, it is possible to ensure a 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] A cup-shaped member 60 is attached to the bottom plate 11 so as to cover the protruding tube 13, the holder 30, and the igniter 40. The cup-shaped member 60 has a generally cylindrical shape with a bottom and an open end on the bottom plate 11 side. The cup-shaped member 60 includes a transfer chamber 65 that contains a transfer charge 66 therein. The cup-shaped member 60 is positioned so as to protrude into the combustion chamber 70 that contains a gas generating agent 71, so that the transfer chamber 65 faces the ignition portion 41 of the igniter 40.

[0040] The cup-shaped member 60 has a top wall portion 61, a cylindrical side wall portion 62 extending from the periphery of the top wall portion 61 toward the bottom plate portion 11, and an extension portion 63 extending radially outward from an open end, which is the end of the side wall portion 62 on the bottom plate portion 11 side. The extension portion 63 is formed to extend along the inner surface of the bottom plate portion 11 of the lower shell 10. Specifically, the extension portion 63 has a curved shape to follow the shape of the inner surface of the bottom plate portion 11 at and near the portion where the protruding cylindrical portion 13 is provided, and includes a tip portion 64 extending in a flange-like shape at its radially outer portion.

[0041] The tip end 64 of the extension portion 63 is disposed between the bottom plate portion 11 and the lower support member 72 along the axial direction of the housing, and is thereby sandwiched between the bottom plate portion 11 and the lower support member 72 along the axial direction of the housing. Here, the lower support member 72 is pressed toward the bottom plate portion 11 by the gas generating agent 71, cushion material 74, upper support member 73, and top plate portion 21 disposed above it, and therefore the tip end 64 of the extension portion 63 of the cup-shaped member 60 is pressed toward the bottom plate portion 11 by the lower support member 72, and the cup-shaped member 60 is fixed to the bottom plate portion 11. This prevents the cup-shaped member 60 from falling off the bottom plate portion 11 without using crimping or press-fitting to secure the cup-shaped member 60.

[0042] Cup-shaped member 60 has no openings in either top wall 61 or side wall 62, and surrounds a space provided therein. When transfer charge 66 is ignited by activation of igniter 40, cup-shaped member 60 bursts or melts due to an increase in pressure in the space inside and conduction of the generated heat, and is made of a fragile material with relatively low mechanical strength.

[0043] Therefore, the cup-shaped member 60 is preferably made of a metal member such as aluminum or an aluminum alloy, or a resin member such as a thermosetting resin represented 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.

[0044] In addition to the above, the cup-shaped member 60 may be made of a metal member with high mechanical strength, such as iron or copper, with an opening in its side wall 62 and sealing tape attached to close the opening. The method of fixing the cup-shaped member 60 is not limited to the above-described fixing method using the lower support member 72, and other fixing methods may also be used.

[0045] The transfer charge 66 filled in the transfer chamber 65 is ignited by the flame generated by the activation of the igniter 40, and generates thermal particles as it burns. The transfer charge 66 needs to be able to reliably start the combustion of the gas generant 71. For this reason, the transfer charge 66 generally used is 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.

[0046] The enhancer charge 66 may be in a powder form or formed into a predetermined shape using a binder. The enhancer charge 66 formed using a binder may have various shapes, such as granular, cylindrical, sheet, spherical, single-hole cylinder, multi-hole cylinder, tablet, etc.

[0047] Within the space inside the housing, the space surrounding the portion in which the cup-shaped member 60 is disposed is a combustion chamber 70 containing a gas generating agent 71. More specifically, as described above, the cup-shaped member 60 is disposed so as to protrude into the combustion chamber 70 formed inside the housing, and the space provided in the portion facing the outer surface of the side wall portion 62 of this cup-shaped member 60 and the space provided in the portion facing the outer surface of the top wall portion 61 form the combustion chamber 70.

[0048] Furthermore, a filter 80 is disposed along the inner periphery of the housing in a space that radially surrounds the combustion chamber 70 containing the gas generating agent 71. The filter 80 has a cylindrical shape. The filter 80 is disposed so that its central axis substantially coincides with the axial direction of the housing.

[0049] The gas generating agent 71 is an agent that generates gas by being ignited by thermal particles generated by the activation of the igniter 40 and burning. A non-azide gas generating agent is preferably used as the gas generating agent 71, and the gas generating agent 71 is generally formed as a molded body containing a fuel, an oxidizer, and an additive.

[0050] 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. More specifically, nitroguanidine, guanidine nitrate, cyanoguanidine, 5-aminotetrazole, or the like is preferably used.

[0051] Examples of oxidizing agents include basic nitrates such as basic copper nitrate, 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.

[0052] Examples of additives include binders, slag formers, and combustion control agents. Suitable binders include organic binders such as metal salts of carboxymethyl cellulose and stearates, and inorganic binders such as synthetic hydrotalcite and acid clay. Suitable slag formers include silicon nitride, silica, and acid clay. Suitable combustion control agents include metal oxides, ferrosilicon, activated carbon, and graphite.

[0053] The shape of the molded body of the gas generating agent 71 may be various, including granular, pellet-like, cylindrical, or other granular shapes, as well as disk-like shapes. Furthermore, among cylindrical molded bodies, perforated molded bodies having through holes inside the molded body (for example, a single-hole cylindrical shape or a multi-hole cylindrical shape) are also used. These shapes are preferably selected appropriately according to the specifications of the airbag device into which the disk-shaped gas generator 1 is incorporated, and it is preferable to select an optimal shape according to the specifications, such as a shape in which the rate of gas generation changes over time when the gas generating agent 71 burns. Furthermore, in addition to the shape of the gas generating agent 71, it is preferable to select the size and filling amount of the molded body appropriately, taking into consideration the linear burning velocity, pressure exponent, etc. of the gas generating agent 71.

[0054] The filter 80 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 by pressing. Specific examples of mesh materials that can be used include knitted wire mesh, plain woven wire mesh, and an aggregate of crimped metal wires.

[0055] Alternatively, a perforated metal sheet wound around the filter 80 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.

[0056] The filter 80 functions as a cooling means for cooling the gas generated in the combustion chamber 70 by removing the high-temperature heat of the gas as the gas passes through the filter 80, 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 70 passes through the filter 80. The filter 80 is disposed at a distance from the side plate portions 12, 22 of the upper shell 20 and the side plate portion 12 of the lower shell 10, which constitute the peripheral wall portion of the housing, so that a gap 26 of a predetermined size is formed between the filter 80 and the side plate portions 12, 22.

[0057] A plurality of gas outlets 24 are provided in the side plate portion 22 of the upper shell 20 in a portion facing the filter 80. The plurality of gas outlets 24 are for directing gas that has passed through the filter 80 to the outside of the housing.

[0058] Additionally, a metal sealing tape 25 is attached to the inner peripheral surface of the side plate portion 22 of the upper shell 20 as a sealing member to close the plurality of gas ejection ports 24. This sealing tape 25 can be suitably made of aluminum foil with an adhesive material applied to one side, or the like, and the sealing tape 25 ensures that the combustion chamber 70 is airtight.

[0059] A lower support member 72 is disposed in the vicinity of the end of the combustion chamber 70 that is located on the bottom plate portion 11 side. The lower support member 72 has an annular shape and is disposed substantially between the filter 80 and the bottom plate portion 11 so as to cover the boundary between the filter 80 and the bottom plate portion 11. As a result, the lower support member 72 is positioned between the bottom plate portion 11 and the gas generating agent 71 in the vicinity of the end of the combustion chamber 70.

[0060] The lower support member 72 has an upright wall portion 72a that stands upright so as to abut against the inner circumferential surface of the axial end portion located on the bottom plate portion 11 side of the filter 80, and a bottom portion 72b that extends radially inward from the upright wall portion 72a. The bottom portion 72b is formed so as to extend along the inner bottom surface of the bottom plate portion 11 of the lower shell 10.

[0061] The lower support member 72 functions as an outflow prevention means for preventing gas generated in the combustion chamber 70 from flowing out through the gap between the lower end of the filter 80 and the bottom plate portion 11 during operation without passing through the inside of the filter 80. The lower support member 72 is formed, for example, by pressing a metal plate-shaped member, and is preferably made of a member made of steel plate such as ordinary steel or special steel (for example, cold-rolled steel plate or stainless steel plate).

[0062] Here, the tip 64 of the extension 63 of the cup-shaped member 60 described above is sandwiched and held between the bottom plate 11 and the bottom 72b along the axial direction of the housing. With this configuration, the tip 64 of the extension 63 of the cup-shaped member 60 is pressed toward the bottom plate 11 by the bottom 72b of the lower support member 72, and the cup-shaped member 60 is fixed to the bottom plate 11.

[0063] An upper support member 73 is disposed at the end of the combustion chamber 70 that is located on the top plate portion 21 side. The upper support member 73 has a generally disk-like shape, and is disposed between the filter 80 and the top plate portion 21 so as to cover the boundary between the filter 80 and the top plate portion 21. As a result, the upper support member 73 is positioned between the top plate portion 21 and the gas generating agent 71 in the vicinity of the end of the combustion chamber 70.

[0064] The upper support member 73 has a standing wall portion 73a that stands upright so as to abut against the inner circumferential surface of the axial end portion that is located on the top plate portion 21 side of the filter 80, and a bottom portion 73b that extends radially inward from the standing wall portion 73a. The standing wall portion 73a abuts against the inner circumferential surface of the axial end portion that is located on the top plate portion 21 side of the filter 80.

[0065] During operation, the upper support member 73 functions as an outflow prevention means for preventing gas generated in the combustion chamber 70 from outflowing through the gap between the upper end of the filter 80 and the top plate portion 21 without passing through the inside of the filter 80. Like the lower support member 72, the upper support member 73 is formed, for example, by pressing a metal plate-shaped member, and is preferably made of a member made of steel plate such as ordinary steel or special steel (for example, cold-rolled steel plate or stainless steel plate).

[0066] A cushioning material 74 is arranged inside this upper support member 73 so as to come into contact with the gas generating agent 71 contained in the combustion chamber 70. As a result, the cushioning material 74 is positioned between the top plate portion 21 and the gas generating agent 71 in the portion of the combustion chamber 70 on the top plate portion 21 side, and presses the gas generating agent 71 toward the bottom plate portion 11 side.

[0067] The cushioning material 74 is provided for the purpose of preventing the gas generating agent 71 made of a molded body from being crushed by vibration, etc. The cushioning material 74 is preferably made of a ceramic fiber molded body, rock wool, foamed resin (for example, foamed silicone, foamed polypropylene, foamed polyethylene, etc.), rubber such as chloroprene and EPDM, or the like.

[0068] Next, with reference to FIG. 1, the operation of disk-shaped gas generator 1 according to the present embodiment described above will be described.

[0069] When a vehicle equipped with disk-shaped gas generator 1 in the present embodiment collides, the collision is detected by collision detection means separately provided in the vehicle, and based on this, igniter 40 is activated by current supplied from a control unit separately provided in the vehicle. Transfer charge 66 contained in transfer charge chamber 65 is ignited by the flame generated by the activation of igniter 40 and burns, generating a large amount of thermal particles. Cup-shaped member 60 bursts or melts due to the combustion of transfer charge 66, and the above-mentioned thermal particles flow into combustion chamber 70.

[0070] The hot particles flowing in ignite and burn the gas generating agent 71 contained in the combustion chamber 70, generating a large amount of gas. The gas generated in the combustion chamber 70 passes through the inside of the filter 80, and in doing so, the filter 80 removes heat and cools the gas, and the slag contained in the gas is removed by the filter 80 and flows into the gap 26.

[0071] As the pressure in the space inside the housing increases, sealing tape 25 that has been closing gas outlet 24 provided in upper shell 20 ruptures, and gas is ejected to the outside of the housing through gas outlet 24. The ejected gas is introduced into the inside of an airbag provided adjacent to disc-shaped gas generator 1, and inflates and deploys the airbag.

[0072] Fig. 2 is an enlarged view of the vicinity of the female connector portion of the disk-type gas generator shown in Fig. 1. Also, Fig. 3 is a perspective view of a ground terminal provided in the disk-type gas generator shown in Fig. 1, with Figs. 3(A) and 3(B) showing the ground terminal as viewed from different directions. Next, with reference to Figs. 2 and 3, the configuration of ground terminal 50 provided in disk-type gas generator 1 according to the present embodiment and the assembly structure of ground terminal 50 will be described in detail.

[0073] 2 and 3, the ground terminal 50 is made of a single conductive member, preferably a press-formed product made by pressing a metal plate. Suitable materials for the ground terminal 50 include stainless steel, steel, iron, aluminum, aluminum alloy, copper, copper alloy, etc.

[0074] As shown in FIG. 3, the ground terminal 50 has a generally cylindrical shape with a flange-like portion at one end, and in the assembled state, as shown in FIG. 2, is embedded in the outer covering portion 32 of the holding portion 30 so as to be positioned along the concave insertion space defined by the female connector portion 34 provided in the outer covering portion 32.

[0075] As a result, as shown in Figure 2, the ground terminal 50 has an abutment portion 51 that abuts against the outer surface of the bottom plate portion 11 located around the protruding tubular portion 13 of the housing, and an exposed portion 52 that faces the insertion space of the female connector portion 34.Furthermore, these abutment portion 51 and exposed portion 52 are connected via a connection portion 53 provided on the ground terminal 50, so that when the male connector of the harness is inserted into the concave insertion space of the female connector portion 34, the ground line provided on the male connector is electrically connected to the housing via the ground terminal 50.

[0076] 3, ground terminal 50 has contact portion 51, which is an annular plate-like member, consisting of the flange-like portion described above, exposed portion 52, which is a cylindrical portion, and connecting portion 53, which is a substantially cylindrical portion connecting contact portion 51 and exposed portion 52. Connecting portion 53 includes a substantially cylindrical upright wall portion 53a extending upward from the inner edge of contact portion 51, and an annular plate-like stepped portion 53b extending radially inward from the upper end of upright wall portion 53a. Exposed portion 52 extends upward from the inner edge of stepped portion 53b.

[0077] Furthermore, the step portion 53b is provided with a plurality of through holes 54 arranged in a dotted row along the circumferential direction. The plurality of through holes 54 serve as paths for the flow of molten resin during injection molding of the holding portion 30, which will be described later.

[0078] 2, in the assembled state, the exposed portion 52 and the connecting portion 53 of the ground terminal 50 are housed inside the protruding cylindrical portion 13 (i.e., the recess 17) of the lower shell 10, and the abutting portion 51 of the ground terminal 50 abuts against the outer surface of the bottom plate portion 11 in the portion located around the protruding cylindrical portion 13 of the housing, as described above. Here, the ground terminal 50 is not in contact with the lower shell 10 except for the abutting portion 51, and neither the exposed portion 52 nor the connecting portion 53 of the ground terminal 50 housed in the protruding cylindrical portion 13 are in contact with the protruding cylindrical portion 13.

[0079] Both the inner and outer surfaces of the connection portion 53 of the ground terminal 50 are covered with the outer covering portion 32 of the holding portion 30. The through-hole 54 provided in the stepped portion 53b of the connection portion 53 is also filled with the outer covering portion 32 of the holding portion 30.

[0080] The upper surface of the contact portion 51 of the ground terminal 50 is covered by the outer covering portion 32 of the holding portion 30 except for the portion that contacts the bottom plate portion 11 of the lower shell 10. The lower surface of the contact portion 51 of the ground terminal 50 is exposed to the outside.

[0081] The ground terminal 50 is located in a portion of the outer covering portion 32 that defines the periphery of the insertion space of the female connector portion 34, and as a result, the inner surface of the exposed portion 52 of the ground terminal 50 is exposed to the outside by facing the concave insertion space of the female connector portion 34. The outer surface of the exposed portion 52 of the ground terminal 50 is covered by the outer covering portion 32 of the holding portion 30.

[0082] As a result, the ground terminal 50 is embedded and held by the outer covering portion 32 with the exposed portion 52 facing the concave insertion space of the female connector portion 34, the connection portion 53 covered by the outer covering portion 32, and the upper surface of the abutting portion 51 abutting against the outer surface of the bottom plate portion 11 at the portion located around the protruding tubular portion 13 of the lower shell 10 with the lower surface of the abutting portion 51 exposed to the outside.

[0083] As described above, in the disk-shaped gas generator 1 according to this embodiment, a configuration is adopted in which abutment portion 51, which is part of ground terminal 50, is pulled out to the outside of protruding tubular portion 13 of lower shell 10 and abuts against the outer surface of bottom plate portion 11 at the portion located around said protruding tubular portion 13. This makes it easy to ensure that ground terminal 50 is securely abutted against the housing, thereby reducing the occurrence of poor connection of ground terminal 50 during manufacturing.

[0084] Figures 4 to 6 are schematic cross-sectional views showing the manufacturing process for the disk-shaped gas generator shown in Figure 1. Here, Figures 4(A) and 4(B) show, in stages, the process of setting the ground terminal in the lower mold, and Figures 5(A) and 5(B) show, in stages, the process of setting the lower shell in the lower mold. Also, Figures 6(A) and 6(B) show, in stages, the process of setting the igniter in the lower mold and the process of setting the upper mold. Next, with reference to Figures 4 to 6, the procedure for assembling ground terminal 50 in disk-shaped gas generator 1 according to this embodiment will be described in detail.

[0085] 4(A) and 4(B), when manufacturing disk-shaped gas generator 1 according to the present embodiment, first, ground terminal 50 is set in lower mold 100. Specifically, ground terminal 50 is fitted onto protruding portion 101 of lower mold 100 for molding female connector portion 34. At this time, ground terminal 50 is fitted onto protruding portion 101 so that abutting portion 51 contacts and covers lower mold 100, and exposed portion 52 contacts and covers the side surface of protruding portion 101.

[0086] 5(A) and 5(B), the lower shell 10 is set on the lower mold 100. Specifically, the lower shell 10 is set on the lower mold 100 so that the protruding portion 101 of the lower mold 100, on which the ground terminal 50 is set, is covered by the protruding tubular portion 13 of the lower shell 10.

[0087] At this time, the outer surface of the bottom plate portion 11 of the lower shell 10 located around the protruding tubular portion 13 is brought into contact with the upper surface of the abutment portion 51 of the ground terminal 50, which is placed in contact with the lower mold 100. As a result, the abutment portion 51 of the ground terminal 50 is sandwiched between the lower mold 100 and the bottom plate portion 11 of the lower shell 10.

[0088] 6(A) and 6(B), igniter 40 is set in lower mold 100, and then upper mold 200 is set. Specifically, terminal pin 42 of igniter 40 is inserted through opening 16 provided in shelf board portion 15 of lower shell 10 into a hole provided in protruding portion 101 of lower mold 100, in which ground terminal 50 and lower shell 10 are set, thereby setting igniter 40 in lower mold 100, and then upper mold 200 is set so as to cover ignition portion 41 of igniter 40 and protruding tubular portion 13 of lower shell 10.

[0089] As a result, a cavity C is formed between lower mold 100 and upper mold 200 so as to surround igniter 40, protruding cylindrical portion 13 of lower shell 10, and ground terminal 50. Here, this cavity C matches the shape of holding portion 30. In other words, the space included in cavity C is all in communication with each other via the gap between lower shell 10 and igniter 40, opening 16 provided in shelf portion 15 of lower shell 10, and through-hole 54 provided in connection portion 53 of ground terminal 50.

[0090] Next, molten resin is injected into the above-mentioned cavity C from the gate 201 provided in the upper mold 200, and then the molten resin filled in the cavity C solidifies, thereby forming the holding portion 30 consisting of a resin molded portion.

[0091] Thereafter, by removing the lower mold 100 and the upper mold 200 from the lower shell 10, etc., the exposed portion 52 of the ground terminal 50 becomes exposed to the outside by facing the concave insertion space of the female connector portion 34 provided in the outer covering portion 32 of the holding portion 30.

[0092] By going through the steps described above, ground terminal 50 is embedded and held by outer covering portion 32 with exposed portion 52 facing the concave insertion space of female connector portion 34, connecting portion 53 covered by outer covering portion 32, and the upper surface of abutting portion 51 abutting against the outer surface of bottom plate portion 11 at a portion located around protruding tubular portion 13 of lower shell 10, with the lower surface of abutting portion 51 exposed to the outside. Therefore, by employing these steps, it is possible to manufacture disc-shaped gas generator 1 according to the present embodiment described above.

[0093] (Variation) Fig. 7 is an enlarged view of the vicinity of a female connector portion of a disk-shaped gas generator according to a modified example. Furthermore, Fig. 8 is a perspective view of a ground terminal provided in the disk-shaped gas generator shown in Fig. 7. Hereinafter, with reference to Figs. 7 and 8, a disk-shaped gas generator 1A according to a modified example based on the embodiment described above will be described. Note that when disk-shaped gas generator 1A according to this modified example is compared with disk-shaped gas generator 1 according to the embodiment described above, only the shapes of exposed portion 52 and connecting portion 53 of ground terminal 50 differ.

[0094] As shown in Figures 7 and 8, in disk-shaped gas generator 1A of this modified example, the upper end of exposed portion 52 of grounding terminal 50 has a shape that is slightly bent inward, and through hole 54 provided in connecting portion 53 is arranged so as to straddle vertical wall portion 53a and step portion 53b, thereby forming a large opening area.

[0095] Even in this configuration, the same effects as those described in the above embodiment can be obtained. Note that, by adopting the above configuration, the rigidity of the exposed portion 52 is increased, and the fluidity of the molten resin during resin molding of the holding portion 30 is improved.

[0096] (Summary of the Disclosure of the Embodiments and Modifications) The characteristic configurations disclosed in the above-described embodiment and modifications can be summarized as follows.

[0097] [Appendix 1] a housing including a top plate portion, a bottom plate portion, and a cylindrical peripheral wall portion provided with a gas outlet, the housing having a combustion chamber therein in which a gas generating agent is accommodated; an igniter including an ignition unit loaded with an ignition charge for burning the gas generating agent and a terminal pin connected to the ignition unit; a resin holding portion provided on the bottom plate portion and holding the igniter, The bottom plate portion includes a cylindrical portion protruding toward the top plate portion side and a shelf portion located at an end of the cylindrical portion on the top plate portion side, and a bottomed cylindrical protruding cylindrical portion is provided with an opening in the shelf portion, The igniter is held by the holding portion in a state where the ignition portion is located closer to the top plate portion than the shelf portion and the terminal pin is inserted into the opening, the holding portion includes a closing portion that closes the opening, an inner covering portion that is fixed to the ignition portion and is fixed to the inner surface of the bottom plate portion at a portion that corresponds to the shelf portion, and an outer covering portion that is fixed to the outer surface of the bottom plate portion at a portion that corresponds to the shelf portion and at a portion that corresponds to the cylindrical portion, the outer covering portion defines a recessed insertion space exposed to the outside, and a female connector portion is provided in which the terminal pins are exposed in the insertion space; The outer covering portion is further provided with a ground terminal made of a conductive material, the ground terminal includes a contact portion that contacts the outer surface of the bottom plate portion at a portion located around the protruding tubular portion, an exposed portion that faces the insertion space, and a connecting portion that connects the contact portion and the exposed portion, the ground terminal is embedded and held by the outer covering portion with the connection portion covered by the outer covering portion and the abutment portion exposed to the outside.

[0098] [Appendix 2] 2. The gas generator according to claim 1, wherein the exposed portion is located in a portion of the female connector portion that defines the circumferential surface of the insertion space.

[0099] [Appendix 3] The contact portion has an annular plate shape, the connecting portion has a stepped annular cylindrical shape, 3. The gas generator according to claim 1, wherein the connection portion is provided with a plurality of through holes.

[0100] [Appendix 4] 4. A gas generator according to any one of appendixes 1 to 3, wherein the ground terminal is made of a metal press-molded product consisting of a single member.

[0101] (Other forms, etc.) The shape, configuration, size, number, material, etc. of each part shown in the above-described embodiment and modified examples can be changed in various ways without departing from the spirit of the present invention.

[0102] Furthermore, the characteristic configurations shown in the above-described embodiments and modifications can be combined with each other without departing from the spirit of the present invention.

[0103] As such, the above-described embodiments and modifications disclosed herein are illustrative in all respects and are not restrictive. The technical scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0104] 1, 1A disk-shaped gas generator, 10 lower shell, 11 bottom plate portion, 12 side plate portion, 13 protruding tubular portion, 14 tubular portion, 15 shelf plate portion, 16 opening, 17 recess, 20 upper shell, 21 top plate portion, 22 side plate portion, 23 flange portion, 24 gas outlet, 25 sealing tape, 26 gap portion, 30 holding portion, 31 inner covering portion, 32 outer covering portion, 33 blocking portion, 34 female connector portion, 40 igniter, 41 ignition portion, 42 terminal pin, 50 ground terminal, 51 abutment portion, 52 exposed portion, 53 connection portion, 53a standing wall portion, 53b step portion, 54 through hole, 60 cup-shaped member, 61 top wall portion, 62 side wall portion, 63 extension portion, 64 Tip portion, 65 transfer chamber, 66 transfer charge, 70 combustion chamber, 71 gas generating agent, 72 lower support member, 72a vertical wall portion, 72b bottom portion, 73 upper support member, 73a vertical wall portion, 73b bottom portion, 74 cushioning material, 80 filter, 100 lower mold, 101 protrusion portion, 200 upper mold, 201 gate, C cavity.

Claims

1. a housing including a top plate portion, a bottom plate portion, and a cylindrical peripheral wall portion provided with a gas outlet, the housing having a combustion chamber therein in which a gas generating agent is accommodated; an igniter including an ignition unit loaded with an ignition charge for burning the gas generating agent and a terminal pin connected to the ignition unit; a resin holding portion provided on the bottom plate portion and holding the igniter, The bottom plate portion includes a cylindrical portion protruding toward the top plate portion side and a shelf portion located at an end of the cylindrical portion on the top plate portion side, and a bottomed cylindrical protruding cylindrical portion is provided with an opening in the shelf portion, The igniter is held by the holding portion in a state where the ignition portion is located closer to the top plate portion than the shelf portion and the terminal pin is inserted into the opening, the holding portion includes a closing portion that closes the opening, an inner covering portion that is fixed to the ignition portion and is fixed to the inner surface of the bottom plate portion at a portion that corresponds to the shelf portion, and an outer covering portion that is fixed to the outer surface of the bottom plate portion at a portion that corresponds to the shelf portion and at a portion that corresponds to the cylindrical portion, The outer covering portion defines a recessed insertion space exposed to the outside, and a female connector portion is provided in which the terminal pins are exposed in the insertion space, The outer covering portion is further provided with a ground terminal made of a conductive material, the ground terminal includes a contact portion that contacts the outer surface of the bottom plate portion at a portion located around the protruding cylindrical portion, an exposed portion that faces the insertion space, and a connecting portion that connects the contact portion and the exposed portion, a gas generator, wherein the ground terminal is embedded and held by the outer covering portion with the connection portion covered by the outer covering portion and the abutment portion exposed to the outside;

2. 2. The gas generator according to claim 1, wherein the exposed portion is located in a portion of the female connector portion that defines a circumferential surface of the insertion space.

3. The contact portion has a circular plate shape, the connecting portion has a stepped annular cylindrical shape, The gas generator according to claim 1 , wherein the connecting portion is provided with a plurality of through holes.

4. 4. The gas generator according to claim 1, wherein the ground terminal is made of a single metal press-molded member.

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