Gas generator

Abstract

To obtain a gas generator capable of improving the mechanical strength of a cup body and capable of stably controlling the size of a rupture of the cup body. The gas generator has a short-length cylindrical housing in which a gas generating agent is accommodated, an igniter including an ignition portion in which an ignition powder is accommodated, and a cup-shaped member in which a transmission chamber in which a transmission powder is accommodated is accommodated, the cup-shaped member being configured from a single bottomed cylindrical member, a thin-walled fragile portion being provided at a portion of a top wall portion of the cup-shaped member, a side wall portion of the cup-shaped member having a higher mechanical strength than the fragile portion, a thin-walled portion being provided at the side of the top wall portion and a thick-walled portion being provided extending from the thin-walled portion in the axial direction to the opposite side of the top wall portion at the side wall portion of the cup-shaped member, the fragile portion having a mechanical strength that causes the cup-shaped member to rupture before the side wall portion as a result of the operation of the igniter, the thin-walled portion having a mechanical strength that ruptures, deforms, or melts in the case where the rupture of the fragile portion progresses to the thin-walled portion.

Description

Technical Field

[0001] This invention relates to a gas generator assembled in an occupant protection device for protecting occupants in the event of a collision in a vehicle or the like, and particularly to a gas generator assembled in an airbag device equipped in automobiles or the like. Background Technology

[0002] Previously, airbags were widely used as occupant protection devices to protect occupants in vehicles and other similar structures. Airbags are installed to protect occupants from the impact of a collision. When a collision occurs, the airbag inflates and deploys instantly, acting as a buffer to protect the occupant's body.

[0003] The gas generator is assembled in the airbag device. When a collision occurs, the igniter is ignited by the power supply from the control unit. The flame generated in the igniter causes the gas generator to burn and instantly produce a large amount of gas, thereby causing the airbag to inflate and deploy.

[0004] Gas generators come in various structures, but those that are particularly suitable for use in driver-side airbag systems, passenger-side airbag systems, etc., include disc-shaped gas generators with a relatively large outer diameter and a short, roughly cylindrical shape.

[0005] The disc-shaped gas generator has a short, generally cylindrical housing that is closed at both ends along the axis. Multiple gas outlets are provided on the peripheral wall of the housing, and a ignition propellant is contained inside the housing in a manner facing an igniter assembled on the housing. In addition, a gas generating agent is filled inside the housing in a manner surrounding the ignition propellant, and a filter is contained inside the housing in a manner further surrounding the gas generating agent.

[0006] For example, Japanese Patent Application Publication No. 2004-217059 (Patent Document 1) discloses the specific structure of this disc-shaped gas generator.

[0007] Patent Document 1 discloses a gas generator in which a cup filled with ignition propellant and an igniter collar holding the igniter body are riveted together by a bent portion on the lower end of a crimping box. The cup is made of a metal such as aluminum and has a weak point on at least one of its closed end face and peripheral wall. The cup is prone to breakage at the weak point, thus reducing the pressure applied to the crimping box and preventing it from falling off or breaking. However, since the cup is made of thin aluminum sheet, it suffers from low mechanical strength and cannot improve its fracture strength during ignition propellant combustion.

[0008] Existing technical documents:

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2004-217059 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] To ensure complete combustion of the ignition propellant, the internal pressure of the cup needs to be increased to accelerate its combustion. This allows the gas-generating agent inside the gas generator to burn effectively within a short time, releasing gas into the gas chamber. However, increasing the mechanical strength of the cup (cup-shaped component) often leads to problems such as cup breakage (fracture), restricted deformation or melting, and unstable fracture sizes, resulting in reduced gas output characteristics. In other words, there is usually a trade-off between increasing the mechanical strength of the cup and controlling the size of fractures (uniformity of the fracture area).

[0013] Therefore, the present invention is proposed to solve the above-mentioned problems, and its purpose is to provide a gas generator that can improve the mechanical strength of the cup body and can control the size of the cup body breakage in a stable manner (uniform fracture area).

[0014] Methods for solving problems

[0015] (1) The gas generator of the present invention comprises a short-sized cylindrical shell, which is composed of a cylindrical peripheral wall portion having a gas outlet, a top plate portion closing one axial end of the peripheral wall portion, and a bottom plate portion closing the other axial end of the peripheral wall portion, and has a combustion chamber containing a gas generating agent inside; an igniter comprising an ignition part mounted on the bottom plate portion and containing an ignition powder that is ignited during operation; and a cup-shaped component comprising a ignition chamber containing a ignition transfer powder, wherein the cup-shaped component is composed of a single bottomed cylindrical component protruding into the combustion chamber such that the internal space of the ignition chamber faces the ignition part. The top wall portion is provided with a thin-walled vulnerable portion, and the cup-shaped member has a side wall portion with a mechanical strength higher than that of the vulnerable portion dividing the ignition chamber and the combustion chamber. The side wall portion has a thin-walled portion disposed on the side of the top wall portion and a thick-walled portion extending axially from the thin-walled portion to the opposite side of the top wall portion. The vulnerable portion is disposed opposite to the ignition portion and has mechanical strength that causes the cup-shaped member to break, deform, or melt before the side wall portion when the igniter is activated. The thin-walled portion has mechanical strength that breaks, deforms, or melts when the breaking, deformation, or melting of the vulnerable portion progresses to the thin-walled portion.

[0016] (2) In the gas generator described in (1) above, it is preferable that the vulnerable portion disposed on the top wall of the cup-shaped member is made of a wall that is thinner than the side wall of the cup-shaped member.

[0017] (3) In the gas generator of (1) or (2) above, preferably, the top wall of the cup-shaped component is composed of a vulnerable area where the combustion of the propellant accompanying the operation of the igniter initially causes cracking, deformation or melting starting from the vulnerable area, and a vulnerable area where cracking, deformation or melting occurs after a predetermined time following deformation in the vulnerable area.

[0018] (4) In the gas generator described in (1) above, it is preferable that the vulnerable part has a slit shape that is radially arranged from the center on the top wall.

[0019] (5) In the gas generator described in (1) above, it is preferable that the cup-shaped component is made of metal or alloy.

[0020] (6) In the gas generator described in (1) above, it is preferable to further include a filter disposed circumferentially on the inner side of the housing; and a support member having an annular plate-shaped base disposed along the inner bottom surface of the base plate portion, an abutting portion abutting against the inner circumferential surface of the end of the filter on the base plate portion side, and a cylindrical upright portion disposed vertically from the base portion toward the top plate portion side, wherein the support member is held on the cup-shaped member by pressing the upright portion into the thick-walled portion of the cup-shaped member.

[0021] (7) In the gas generator described in (1) above, it is preferable that a filter is also provided circumferentially inside the housing, and the cup-shaped component further includes an annular plate-shaped base provided along the direction of the inner bottom surface of the base plate, an abutting portion abutting against the inner circumferential surface of the end of the filter on the base plate side, and a cylindrical upright portion erected vertically from the base to the top plate side, the upright portion extending integrally from the side wall portion of the cup-shaped component.

[0022] The effects of the invention

[0023] According to the present invention, a gas generator can be obtained that both improves the mechanical strength of the cup body and stabilizes the size of the cup body's fracture (homogenization of the fracture region). Furthermore, because the size of the cup body's fracture is stabilized (homogenization of the fracture region), a gas generator can be constructed that can achieve the desired performance while reducing the amount of propellant. Attached Figure Description

[0024] Figure 1 This is a schematic cross-sectional view of a disc-shaped gas generator according to an embodiment of the present invention.

[0025] Figure 2 for Figure 1 A three-dimensional view of the cup-shaped component of a disc-shaped gas generator.

[0026] Figure 3 For illustrative purposes Figure 1 A schematic cross-sectional view of the operation of a disc-shaped gas generator.

[0027] Figure 4 A graph illustrating the test conditions and results of the verification test.

[0028] Figure 5 (a) is a schematic cross-sectional view of the shape of the cup-shaped component used for the verification test, and (b) is a diagram showing the test conditions and test results of the verification test.

[0029] Figure 6 (a) is a schematic cross-sectional view of the shape of the cup-shaped component used for the verification test, and (b) is a diagram showing the test conditions and test results of the verification test.

[0030] Figure 7 This is a perspective view of a cup-shaped component according to a modified embodiment of the present invention.

[0031] Figure 8 This is a schematic cross-sectional view of a gas generator according to a modified embodiment of the present invention.

[0032] Figure 9 This is a schematic cross-sectional view of a gas generator according to a modified embodiment of the present invention.

[0033] Figure 10 This is a perspective view of the cup-shaped component of various modifications of embodiments of the present invention.

[0034] Figure 11 This is a schematic cross-sectional view of a gas generator according to a modified embodiment of the present invention. Detailed Implementation

[0035] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the embodiments shown below, the present invention is applied to a disc-shaped gas generator suitable for assembly into an airbag device mounted on an automobile steering wheel, etc. Furthermore, in the embodiments shown below, the same or common parts are given the same reference numerals in the drawings and will not be described again.

[0036] Figure 1 This is a schematic diagram of a disc-shaped gas generator 100 according to an embodiment of the present invention. First, refer to this... Figure 1 The structure of the disc-shaped gas generator 100 in this embodiment will be described.

[0037] like Figure 1As shown, the disc-shaped gas generator 100 has a short, generally cylindrical housing that is closed at one and the other ends along its axial direction. Within the housing's internal space are housed internal components such as a retainer 30, an igniter 40, a cup-shaped component 50, a propellant 59, a gas generating agent 61, a lower support component 70, an upper support component 80, a buffer component 85, and a filter 90. Furthermore, a combustion chamber 60, which primarily houses the gas generating agent 61 from the aforementioned internal components, is located within the housing's internal space.

[0038] The housing includes a lower side housing 10 and an upper side housing 20. The lower side housing 10 and the upper side housing 20 are each made of stamped parts, for example, formed by stamping rolled metal sheet parts. As the metal sheet parts constituting the lower side housing 10 and the upper side housing 20, metal sheets made of stainless steel, steel, aluminum alloy, stainless steel alloy, etc. are used, and so-called high-tensile steel sheets that will not break or suffer damage even when subjected to tensile stress of 440 [MPa] to 780 [MPa] are used.

[0039] The lower side shell 10 and the upper side shell 20 are each formed into a bottomed, generally cylindrical shape, and are assembled by joining them together with their openings facing each other. The lower side shell 10 has a bottom plate portion 11 and a peripheral wall portion 12, and the upper side shell 20 has a top plate portion 21 and a peripheral wall portion 22.

[0040] The upper end of the peripheral wall portion 12 of the lower side housing 10 is pressed in by inserting it into the lower end of the peripheral wall portion 22 of the upper side housing 20. Furthermore, the peripheral wall portion 12 of the lower side housing 10 and the peripheral wall portion 22 of the upper side housing 20 are joined at or near their abutment, thereby fixing the lower side housing 10 and the upper side housing 20. Here, electron beam welding, laser welding, friction pressing, etc., can preferably be used in the joining of the lower side housing 10 and the upper side housing 20.

[0041] Therefore, the portion of the peripheral wall of the housing near the bottom plate 11 is formed by the peripheral wall portion 12 of the lower side housing 10, and the portion of the peripheral wall of the housing near the top plate 21 is formed by the peripheral wall portion 22 of the upper side housing 20. In addition, one end and the other end of the housing in the axial direction are respectively closed by the bottom plate portion 11 of the lower side housing 10 and the top plate portion 21 of the upper side housing 20.

[0042] A protruding cylindrical portion 13 protruding toward the top plate portion 21 is provided at the center of the bottom plate portion 11 of the lower side housing 10, thereby forming a recessed portion 14 at the center of the bottom plate portion 11 of the lower side housing 10. The protruding cylindrical portion 13 is the part for fixing the igniter 40 via the retaining portion 30, and the recessed portion 14 is the part for providing space for the female connector portion 34 within the retaining portion 30.

[0043] The protruding cylindrical portion 13 is formed into a generally cylindrical shape with a base, and at its axial end located on the side of the top plate portion 21, there is an opening 15 with a non-point-symmetric shape (e.g., D-shaped, barrel-shaped, oblong shape, etc.) in a top view. This opening 15 is the part where a pair of terminal pins 42 of the igniter 40 are inserted.

[0044] The igniter 40 is used to generate a flame and has an ignition part 41 and the aforementioned pair of terminal pins 42. The ignition part 41 contains an ignition charge that generates a flame by ignition and combustion during operation, and a resistor for igniting the ignition charge. The pair of terminal pins 42 are connected to the ignition part 41 to ignite the ignition charge.

[0045] More specifically, the ignition part 41 has a cup-shaped detonation tube cup and a plug that closes the open end of the detonation tube cup and holds it by inserting a pair of terminal pins 42. It has a structure in which a resistor (bridge wire) is installed in such a way as to connect to the front end of the pair of terminal pins 42 inserted into the detonation tube cup, and ignition powder is filled in the detonation tube cup in such a way as to surround or approach the resistor.

[0046] Here, nickel-chromium alloy wire is typically used as the resistive element, while ZPP (zirconium-potassium perchlorate), ZWPP (zirconium-tungsten-potassium perchlorate), and lead trioctate are commonly used as the ignition source. Furthermore, the aforementioned burst tube cup and plug are generally made of metal or plastic.

[0047] Upon detection of a collision, a specified current flows through terminal pin 42 into the resistive element. The flow of this specified current generates Joule heat within the resistive element, initiating combustion of the ignition charge. The high-temperature flame produced by combustion causes the bursting tube cup containing the ignition charge to rupture. The time from the current flowing through the resistive element to the activation of the igniter 40 is typically less than 2 ms, provided the resistive element is made of nichrome wire.

[0048] The igniter 40 is installed on the base plate 11 in a state of insertion from the inside of the lower side housing 10, such that the terminal pin 42 is inserted into the opening 15 provided in the protruding cylindrical portion 13. Specifically, a retaining portion 30 made of resin molding is provided around the protruding cylindrical portion 13 provided in the base plate 11, and the igniter 40 is held by the retaining portion 30, thereby being fixed to the base plate 11.

[0049] The retaining part 30 is formed by injection molding (more specifically, embedding molding) using a mold. It is formed by adhering an insulating, fluid resin material to the base plate 11 and allowing it to cure, through an opening 15 provided in the base plate 11 of the lower side housing 10, from a part of the inner surface of the base plate 11 to a part of the outer surface. It has a structure that allows the ignition charge to be filled into the detonation tube cup in a contact manner.

[0050] Here, nickel-chromium alloy wire is typically used as the resistive element, while ZPP (zirconium-potassium perchlorate), ZWPP (zirconium-tungsten-potassium perchlorate), and lead trioctate are commonly used as the ignition source. Furthermore, the aforementioned burst tube cup and plug are generally made of metal or plastic.

[0051] Upon detection of a collision, a specified current flows through terminal pin 42 into the resistive element. The flow of this specified current generates Joule heat within the resistive element, initiating combustion of the ignition charge. The high-temperature flame produced by combustion causes the bursting tube cup containing the ignition charge to rupture. The time from the current flowing through the resistive element to the activation of the igniter 40 is typically less than 2 ms, provided the resistive element is made of nichrome wire.

[0052] The igniter 40 is installed on the base plate 11 in a state of insertion from the inside of the lower side housing 10, such that the terminal pin 42 is inserted into the opening 15 provided in the protruding cylindrical portion 13. Specifically, a retaining portion 30 made of resin molding is provided around the protruding cylindrical portion 13 provided in the base plate 11, and the igniter 40 is held by the retaining portion 30, thereby being fixed to the base plate 11.

[0053] The retaining part 30 is formed by injection molding (more specifically, embedding molding) using a mold. It is formed by attaching an insulating, fluid resin material to the base plate 11 and curing it by means of extending from a part of the inner surface of the base plate 11 to a part of the outer surface via an opening 15 provided in the base plate 11 of the lower side housing 10.

[0054] As the raw material for the retaining part 30 formed by injection molding, a resin material with excellent heat resistance, durability, and corrosion resistance after curing is preferably 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 or nylon 66), polypropylene vulcanizate resin, and polypropylene oxide resin can also be used. When these thermoplastic resins are selected as raw materials, in order to ensure the mechanical strength of the molded retaining part 30, these resin materials preferably contain fillers such as glass fibers. However, if sufficient mechanical strength can be ensured using only thermoplastic resin, it is not necessary to add fillers as described above.

[0055] The retaining part 30 includes an inner covering part 31 that covers a portion of the inner surface of the bottom plate part 11 of the lower side housing 10, an outer covering part 32 that covers a portion of the outer surface of the bottom plate part 11 of the lower side housing 10, and a connecting part 33 located in the opening 15 provided in the bottom plate part 11 of the lower side housing 10 and connected to the inner covering part 31 and the outer covering part 32 respectively.

[0056] The retaining part 30 is fixed to the base plate 11 on the surfaces of the inner cover part 31, the outer cover part 32, and the connecting part 33, respectively. In addition, the retaining part 30 is fixed to the side and bottom of the portion of the igniter 40 near the lower end of the ignition part 41, and to the surface of the portion of the igniter 40 near the upper end of the terminal pin 42.

[0057] Thus, the opening 15 is completely embedded by the terminal pin 42 and the retaining part 30, ensuring the airtightness of the space inside the housing by ensuring the sealing of this part. In addition, since the opening 15 is formed as described above with a non-point-symmetrical shape when viewed from above, by embedding the opening 15 with the connecting part 33, these openings 15 and the connecting part 33 also serve as an anti-rotation mechanism to prevent the retaining part 30 from rotating relative to the base plate part 11.

[0058] A female connector portion 34 is formed on the outer side cover portion 32 of the retaining portion 30 facing outward. This female connector portion 34 is a portion for receiving a male connector (not shown) for connecting the wiring harness of the igniter 40 and the control unit (not shown), and is located in the recess 14 of the bottom plate portion 11 of the lower side housing 10.

[0059] Within the female connector section 34, the portion of the igniter 40 near the lower end of the terminal pin 42 is exposed. A male connector is inserted into the female connector section 34, thereby achieving electrical connection between the core wire of the wiring harness and the terminal pin 42.

[0060] Alternatively, the lower side shell 10, which has an adhesive layer pre-applied at a predetermined position on the surface of the base plate portion 11 covered by the holding portion 30, can also be injection molded as described above. This adhesive layer can be formed by pre-applying adhesive at a predetermined position on the base plate portion 11 and allowing it to cure.

[0061] In this way, since the cured adhesive layer is located between the base plate portion 11 and the retaining portion 30, the retaining portion 30, which is made of resin molding portion, can be more firmly fixed to the base plate portion 11. Therefore, if the adhesive layer is provided in a circumferential ring around the opening 15 provided in the base plate portion 11, a higher sealing performance can be ensured in this part.

[0062] Here, as an adhesive pre-applied to the base plate 11, it is preferable to use an adhesive that contains a resin material with excellent heat resistance, durability, and corrosion resistance after curing. In particular, it is preferable to use an adhesive containing, for example, cyanoacrylate resin or silicone resin as a raw material. In addition to the resin materials mentioned above, adhesives containing 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, polyamide-imide resins, liquid crystal polymers, styrene rubbers, and olefin rubbers as raw materials can also be used as the aforementioned adhesives.

[0063] Furthermore, although this example illustrates a structure in which the igniter 40 can be fixed relative to the lower side housing 10 by injection molding the retaining part 30, which is made of resin molding part, other alternative solutions can also be used to fix the igniter 40 relative to the lower side housing 10.

[0064] A cup-shaped component 50 is assembled on the base plate 11 to cover the protruding cylindrical portion 13, the retaining portion 30, and the igniter 40. The cup-shaped component 50 has a bottomed, generally cylindrical shape with an end opening on the side of the base plate 11, and contains a space for accommodating the propellant 59. The cup-shaped component 50 is positioned protruding into the combustion chamber 60, which contains the gas generating agent 61, with its internal space facing the ignition portion 41 of the igniter 40.

[0065] The cup-shaped component 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 a flange portion 62 extending radially outward from an open end that serves as the end of the bottom plate portion 11 of the side wall portion 52.

[0066] The sidewall portion 52 has a thin-walled portion 52a disposed on the side of the top wall portion 51, and a thick-walled portion 52b extending axially from the thin-walled portion 52a to the side opposite to the top wall portion 51. The thin-walled portion 52a is thicker than the weak portion 55 and thinner than the thick-walled portion 52b, and has mechanical strength to break, deform, or melt according to the fracture, deformation, or melting of the weak portion 55.

[0067] The flange portion 62 has a shape that curves radially outward parallel to the annular portion of the protruding cylindrical portion 13. Therefore, there is no structure that clamps a portion of the cup-shaped portion 50 between the lower support member 70 and the bottom plate portion 11 of the lower side housing 10.

[0068] The cup-shaped component 50 has no openings in either the side wall portion 52 or the top wall portion 51, and surrounds the space disposed therein. When the igniter 40 is activated and the propellant 59 inside the ignition chamber is ignited, the cup-shaped component 50 may rupture, deform, or melt due to the increase in pressure in its internal space or the conduction of the generated heat.

[0069] The cup-shaped component 50 is preferably made of metals such as stainless steel, iron, aluminum, aluminum alloys, stainless steel, and stainless steel alloys, or of resins such as thermosetting resins (e.g., epoxy resin), thermoplastic resins (e.g., polybutylene terephthalate resin, polyethylene terephthalate resin, polyamide resin (e.g., nylon 6 or nylon 66), polypropylene vulcanizate resin, and polypropylene oxide resin). Aluminum alloys or ferrous metals such as stainless steel and iron, which have higher mechanical strength than aluminum, are particularly preferred.

[0070] Furthermore, the method of fixing the cup-shaped component 50 is not limited to the method of fixing the lower support component 70 described above; other methods of fixing may also be used.

[0071] At least a portion of the top wall 51 of the cup-shaped member 50 is provided with a weak portion 55 that is thinner than the side wall 52. The weak portion 55 is provided by radially extending slits and is configured to have lower mechanical strength than the side wall 52 of the cup-shaped member 50. Here, the weak portion 55 is arranged opposite to the ignition portion 41 of the igniter 40. In addition, a non-weak portion 56, which is thicker than the weak portion 55 and comparable in thickness to the thick-walled portion 52b, is provided on the portion of the top wall 51 other than the radially extending weak portion 55.

[0072] Therefore, the internal space of the cup-shaped component 50 is such that after the vulnerable part 55 is broken, deformed, or melted by the thrust generated by the combustion of the propellant 59, the thin-walled part 52a also breaks, deforms, or melts according to the breaking, deformation, or melting of the vulnerable part 55, and the mechanical strength of the vulnerable part 55 and the thin-walled part 52a is relatively low. On the other hand, the non-vulnerable part 56 and the thick-walled part 52b are formed to be thicker than the vulnerable part 55, so that even if the propellant 59 burns during the operation of the igniter 40, they remain.

[0073] Furthermore, the thicknesses of the aforementioned vulnerable portion 55 and thin-walled portion 52a, and the thicknesses of the non-vulnerable portion 56 and thick-walled portion 52b, are appropriately adjusted according to the type and amount of propellant 59 used, as shown in one example. For instance, when the cup-shaped component is made of iron, stainless steel, or aluminum alloy, the thickness of the aforementioned vulnerable portion 55 and thin-walled portion 52a is 0.6 mm or less, preferably 0.3 mm or less. On the other hand, when the cup-shaped component 50 is made of iron, stainless steel, or aluminum alloy, the thickness of the non-vulnerable portion 56 and thick-walled portion 52b is greater than the thickness of the vulnerable portion 55 and thin-walled portion 52a, and is 0.3 mm or more and 0.9 mm or less, preferably 0.4 mm or more and 0.6 mm or less.

[0074] The ignition charge 59, filled in the ignition chamber, is ignited by the flame generated by the igniter 40, producing hot particles through combustion. As the ignition charge 59, it must be able to reliably initiate the combustion of the gas generator 61. Generally, compositions composed of metal powders / oxidants, such as B / KNO3, B / NaNO3, and Sr(NO3)2, or compositions composed of titanium hydride / potassium perchlorate, or compositions composed of B / 5-aminotetrazole / potassium nitrate / molybdenum trioxide, etc., can be used.

[0075] The ignition source 59 can be in powder form or formed into a predetermined shape by an adhesive. The shape of the ignition source 59 formed by the adhesive can be various, such as granular, cylindrical, flake, spherical, single-hole cylindrical, multi-hole cylindrical, or flat.

[0076] Within the space inside the housing, a combustion chamber 60 containing the gas generating agent 61 is disposed in the space surrounding the portion where the cup-shaped member 50 is arranged. Specifically, as described above, the cup-shaped member 50 protrudes into the combustion chamber 60 formed inside the housing, and the space provided on the outer surface of the top wall portion 51 facing the cup-shaped member 50 and the space provided on the outer surface of the side wall portion 52 constitute the combustion chamber 60. Thus, the gas generating agent 61 is disposed adjacent to the outer surface of the cup-shaped member 50.

[0077] Furthermore, a filter 90 is arranged along the inner circumference of the housing in the space surrounding the combustion chamber 60 containing the gas generating agent 61 radially. The filter 90 has a cylindrical shape, and its central axis is substantially aligned with the axial direction of the housing.

[0078] The gas generator 61 is a reagent that generates gas by ignition and combustion of thermal particles produced by the operation of the igniter 40. As the gas generator 61, a non-azide gas generator is preferred, and the gas generator 61 is usually formed into a molded body containing fuel, oxidant and additives.

[0079] As a fuel, triazole derivatives, tetraazole derivatives, guanidine derivatives, azodicarbonamide derivatives, hydrazine derivatives, or combinations thereof can be used. Specifically, nitroguanidine, guanidine nitrate, cyanoguanidine, 5-aminotetrazole, etc., are preferred, for example.

[0080] As oxidizing agents, alkaline metal hydroxides such as basic copper nitrate or 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 ammonium can be used. As nitrates, sodium nitrate and potassium nitrate are preferred, for example.

[0081] Examples of additives include binders, slag-forming agents, and combustion regulators. For binders, preferred choices include organic binders such as polyvinyl alcohol, metal salts of carboxymethyl cellulose, and stearates, and inorganic binders such as synthetic hydrotalcite and acid clay. Additionally, preferred 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, or inorganic binders such as molybdenum disulfide, talc, bentonite, diatomaceous earth, kaolin, and alumina. For slag-forming agents, preferred choices include silicon nitride, silica, and acid clay. For combustion regulators, preferred choices include metal oxides, ferrosilicon, activated carbon, and graphite.

[0082] The gas generator 61 can be molded into various shapes, including granular, micro-pellet, cylindrical, and disc-shaped forms. Additionally, cylindrical forms can also be perforated (e.g., single-hole or multi-hole cylinder shapes) with through-holes inside. These shapes are preferably selected appropriately based on the specifications of the gasbag assembly of the disc-shaped gas generator 100, with the optimal shape corresponding to the specifications being preferred, such as a shape that reflects the change in gas generation rate over time during combustion of the gas generator 61. Furthermore, in addition to the shape of the gas generator 61, the size and filling amount of the molded form are preferably selected appropriately, taking into account the linear combustion rate and pressure index of the gas generator 61.

[0083] Filter 90 can be, for example, a filter made by winding and sintering metal wires such as stainless steel or steel, or a filter made by pressing and compacting a mesh woven with metal wires. As a mesh material, specifically, it can be a wire mesh woven from knitted fabric or a wire mesh made of plain weave fabric, or an assembly of metal wires made of curled fabric, etc.

[0084] Alternatively, a filter with a perforated metal plate wound around it can be used as filter 90. In this case, the perforated metal plate can be, for example, a steel mesh formed by pushing open the metal plate with serrated cuts and processing it into a mesh shape, or a hook metal plate that is flattened by perforating the metal plate and flattening the burrs generated around the holes. In this case, the size and shape of the formed holes can be changed as needed, and different sizes and shapes of holes can be contained in the same metal plate. In addition, steel plates (mild steel) or stainless steel plates are preferred as metal plates, and non-ferrous metal plates such as aluminum, copper, titanium, nickel or their alloys can also be used.

[0085] When the gas generated in the combustion chamber 60 passes through the filter 90, the filter 90 functions as a cooling mechanism to cool the gas by removing the high temperature of the gas, and also as a removal mechanism to remove residues (slag) contained in the gas. Therefore, in order to adequately cool the gas and prevent the release of residues to the outside, it is necessary to ensure that the gas generated in the combustion chamber 60 passes through the filter 90. In addition, the filter 90 is disposed separately from the peripheral walls 12 and 22, such that a gap 28 of a predetermined size is formed between the peripheral wall 12 of the lower side housing 10 and the peripheral wall 22 of the upper side housing 20, which constitute the peripheral wall of the housing.

[0086] A plurality of gas outlets 23 are provided on the peripheral wall 22 of the upper side housing 20 facing the filter 90. These plurality of gas outlets 23 are used to exhaust the gas passing through the filter 90 to the outside of the housing.

[0087] Furthermore, a metal sealing strip 24, serving as a sealing component, is affixed to the inner circumferential surface of the peripheral wall portion 22 of the upper side housing 20 to seal the aforementioned plurality of gas outlets 23. This sealing strip 24 can preferably be made of aluminum foil or similar material coated on one side with an adhesive component, and its sealing strip 24 ensures the airtightness of the combustion chamber 60.

[0088] A lower support member 70 is disposed near the end of the combustion chamber 60 on the side of the bottom plate portion 11. The lower support member 70 has an annular shape and is disposed substantially close to the filter 90 and the bottom plate portion 11 in order to cover the junction of the filter 90 and the bottom plate portion 11. Thus, the lower support member 70 is located between the bottom plate portion 11 and the gas generating agent 61 near the aforementioned end of the combustion chamber 60.

[0089] The lower support member 70 has an annular plate-shaped base 71 that is close to the inner bottom surface of the base plate 11, an abutting portion 72 that abuts against the inner peripheral surface of the base plate 11 near the filter 90, and a cylindrical erecting portion 73 that is erected vertically from the base 71 toward the top plate 21. The abutting portion 72 extends from the outer edge of the base 71, and the erecting portion 73 extends from the inner edge of the base 71. The erecting portion 73 covers the outer peripheral surface of the protruding cylindrical portion 13 of the lower side housing 10 and the outer peripheral surface of the inner cover portion 31 of the retaining portion 30.

[0090] The lower support member 70 is used to fix the filter 90 to the housing, and also functions as an outflow prevention mechanism to prevent gas generated in the combustion chamber 60 during operation from flowing out through the gap between the lower end of the filter 90 and the base plate 11 without passing through the interior of the filter 90. Therefore, the lower support member 70 is formed, for example, by stamping a metal plate, and is preferably made of steel plate such as ordinary steel or special steel (e.g., cold-rolled steel plate or stainless steel plate).

[0091] An upper support member 80 is disposed at the end of the combustion chamber 60 located on the side of the top plate portion 21. The upper support member 80 has a generally disc-shaped shape and is disposed close to the filter 90 and the top plate portion 21 to cover the junction of the filter 90 and the top plate portion 21. Thus, the upper support member 80 is located between the top plate portion 21 and the gas generating agent 61 near the aforementioned end of the combustion chamber 60.

[0092] The upper support member 80 has a base 81 that abuts against the top plate portion 21 and an abutment portion 82 that is erected vertically from the periphery of the base 81. The abutment portion 82 abuts against the inner circumferential surface of the axial end located on the top plate portion 21 side of the filter 90.

[0093] The upper support member 80 is used to fix the filter 90 to the housing, and also functions as an outflow prevention mechanism to prevent gas generated in the combustion chamber 60 during operation from flowing out through the gap between the lower end of the filter 90 and the top plate portion 21 without passing through the interior of the filter 90. Therefore, the upper support member 80 is formed, for example, by stamping a metal plate, and is preferably made of steel plate such as ordinary steel or special steel (e.g., cold-rolled steel plate or stainless steel plate).

[0094] Inside the upper support member 80, a disc-shaped buffer material 85 is disposed in contact with the gas generating agent 61 contained in the combustion chamber 60. Thus, the portion of the buffer material 85 on the top plate portion 21 side of the combustion chamber 60 is located between the top plate portion 21 and the gas generating agent 61, pressing the gas generating agent 61 toward the bottom plate portion 11.

[0095] The cushioning material 85 is provided to prevent the gas generator 61, which is composed of a molded body, from being crushed due to vibration or the like. It is preferably composed of a molded body of ceramic fiber or a component made of rock wool, foamed resin (such as foamed silicone, foamed polypropylene, foamed polyethylene, foamed polyurethane, etc.), or rubber such as chloroprene and EPDM.

[0096] Next, refer to Figure 1 The assembly procedure for the disc-shaped gas generator 100 of this embodiment will be explained.

[0097] First, the igniter 40 is fixed in the lower side housing 10 by injection molding a retaining part 30 made of resin molding part. Then, it is fixed by pressing the side wall 52 of the cup-shaped member 50, which contains the propellant 59, into the retaining part 30 of the lower side housing 10.

[0098] Next, gas generator 61 is filled inside the filter 90, and the upper support member 80, which contains cushioning material 85, is inserted into the upper part of the filter 90. Then, the upper side housing 20, which has the gas outlet 23 sealed by the sealing strip 24, is covered relative to the lower side housing 10, and the lower side housing 10 and the upper side housing 20 are welded together. This completes the process. Figure 1 Assembly of the gas generator 100 with the structure shown.

[0099] In this embodiment of the disc-shaped gas generator 100, since no opening is provided on the cup-shaped member 50, the process of filling the ignition chamber 57 provided inside the cup-shaped member 50 with the ignition propellant 59 can be performed very easily. This is because, when the disc-shaped gas generator 100 is operating, the cup-shaped member 50 itself is made of a fragile component with low mechanical strength, which can cause a portion of the cup-shaped member to crack, deform, or melt. That is, the operation of closing the opening provided on the cup-shaped member for filling the ignition propellant 59, which is required when using a cup-shaped member with an opening, is not necessary. For example, aluminum strips or sealing plates are not required, thus greatly simplifying the manufacturing process.

[0100] Figure 3 This is a schematic cross-sectional view used to illustrate the operation of the disc gas generator in this embodiment. Next, refer to this... Figure 3 and the above Figure 1 The operation of the disc gas generator 100 in this embodiment will be explained.

[0101] Reference Figure 1In the event of a collision involving a vehicle equipped with a disc-shaped gas generator 100, a collision is detected by a collision detection mechanism separately installed on the vehicle. Based on this, the igniter 40 is activated by energizing a control unit separately installed on the vehicle. The ignition charge 59 contained in the ignition chamber 57 is ignited by the flame generated by the igniter 40 and begins to burn.

[0102] At this time, as Figure 3 As shown, immediately after the igniter 40 is activated, the ignition charge in the ignition section 41 ruptures due to the rapid combustion of the ignition charge, and the thrust generated by the rapid combustion of the ignition charge propagates to the ignition charge 59 filled in the ignition chamber 57.

[0103] like Figure 3 As shown, the thrust reaches the top wall 51 of the cup-shaped component 50, causing the vulnerable portion 55 of the cup-shaped component 50, which is composed of vulnerable components, to crack, deform, or melt. The cracking, deformation, or melting of the vulnerable portion 55 of the cup-shaped component 50 occurs later than the ignition of the propellant 59 caused by the hot particles generated by the combustion of the igniter. Furthermore, since there is no vulnerable portion 55 in the side wall 52 but there is a vulnerable portion 55 in the top wall 51, the cracking, deformation, or melting occurs first in the vulnerable portion 55 of the top wall 51, causing the internal pressure to rise to the point of cracking, deformation, or melting of the top wall 51. Here, the propellant 59 of the cup-shaped component 50 is dispersed inside the cup-shaped component 50 by the thrust generated by the combustion of the igniter, becoming dispersed. Figure 2 As shown, the vulnerable portion 55 is provided as a slit, and it first cracks, deforms, or melts from the top wall portion 51 of the cup-shaped member 50, and then cracks in the thin-walled portion 52a of the side wall portion 52. The thin-walled portion 52a cracks, deforms, or melts again depending on the cracking (fracture), deformation, or melting of the vulnerable portion 55, until the connection with the thick-walled portion 52b cracks. Here, the thick-walled portion 52b does not crack, deform, or melt.

[0104] Therefore, within a shorter time, the propellant 59, which is farther from the igniter 40, is also ignited by the hot particles and begins to burn. As a result, the pressure and temperature inside the cup-shaped component 50 increase significantly. Consequently, within a shorter time, the weak part 55 and the thin-walled part 52a of the cup-shaped component 50 successively crack, deform, or melt, and a large number of hot particles generated by the combustion of the propellant 59 flow into the combustion chamber 60 prematurely.

[0105] In particular, Figure 1In this design, the cup-shaped component 50 is made of iron or stainless steel, which has higher strength than aluminum. Therefore, during the initial stage of combustion of the propellant 59, the cup-shaped component 50 will not crack, deform, or melt. At this time, the internal pressure of the cup-shaped component 50 increases until a predetermined time is reached during which the vulnerable part 55 of the cup-shaped component cracks, deforms, or melts. Moreover, when the internal pressure reaches a certain level, the vulnerable part 55 and the thin-walled part 52a of the cup-shaped component 50 crack, deform, or melt in sequence. Therefore, by using a ferrous metal material with high mechanical strength, such as iron or stainless steel, the mechanical strength of the cup-shaped component 50 is improved, thereby sufficiently promoting the combustion of the propellant 59 when the cup-shaped component 50 cracks, and enabling the cup-shaped component 50 to crack under conditions that promote the combustion of the gas generator 61. This improvement in the mechanical strength of the cup-shaped component 50 can be achieved even when using a metal with low strength, such as aluminum, by increasing its thickness. The thickness is preferably 0.4 mm to 1.5 mm, more preferably 0.6 mm to 1.2 mm.

[0106] In this way, a large number of hot particles flow into the combustion chamber 60, and the gas generating agent 61 contained in the combustion chamber 60 is ignited and burned, producing a large amount of gas. The gas generated in the combustion chamber 60 passes through the interior of the filter 90, where it is cooled by the heat removed by the filter 90, and the slag contained in the gas is removed by the filter 90 and flows into the gap 28.

[0107] Below, refer to Figure 1 In the case of using the disc-shaped gas generator 100 in the embodiment of the present invention, a mechanism that can appropriately control the transfer of flame energy by the ignition charge 59 will be described.

[0108] like Figure 2 As shown, in the disc-shaped gas generator 100 of this embodiment, the top wall portion 51 of the cup-shaped member 50 is radially thinner than other portions, thus forming a vulnerable portion 55. Furthermore, by making the remaining portion of the top wall portion 51 of the cup-shaped member 50 thicker than the vulnerable portion 55, a non-vulnerable portion 56 is formed. Moreover, the thin-walled portion 52a of the side wall portion 52 of the cup-shaped member 50 is configured to be thicker than the vulnerable portion 55 but thinner than the thick-walled portion 52b, while the thick-walled portion 52b of the side wall portion 52 of the cup-shaped member 50 is configured to be thicker than both the vulnerable portion 55 and the thin-walled portion 52a, with a thickness similar to that of the non-vulnerable portion 56.

[0109] With this configuration, the vulnerable portion 55 first breaks, deforms, or melts. Here, since the cup-shaped component 50 breaks, deforms, or melts from the portion that serves as the starting point, there is no risk of breaking, deforming, or melting from the sidewall portion 52 where the vulnerable portion 55 does not exist. After the propellant 59 has fully burned, the top wall portion 51 breaks, deforms, or melts. Then, starting from the broken, deformed, or melted vulnerable portion 55, the top wall portion 51 cracks along the vulnerable portion 55. After the top wall portion 51 cracks, the cracking reaches the thin-walled portion 52a of the sidewall portion 52, directly causing the thin-walled portion 52a of the sidewall portion 52 to crack. Then, at the connection between the thin-walled portion 52a and the thick-walled portion 52b, the cracking stops. Thus, since the cracking is along the length direction of the vulnerable portion 55, it is petal-shaped until the connection between the thin-walled portion 52a and the thick-walled portion 52b. Therefore, by stopping the cup-shaped component 50 from cracking to the middle (the connection between the thin-walled portion 52a and the thick-walled portion 52b), the cup-shaped component 50 expands towards the top plate portion 21 over time, and the size of the fracture of the cup-shaped component 50 opens in a stable state, so the hot particles generated by the combustion of the propellant 59 flow more directionally into the top plate portion 21.

[0110] Specifically, in the first stage of cracking, where the weak part 55 cracks, deforms, or melts, and the non-weak part of the top wall 51 cracks starting from the weak part 55, the top wall 51 of the cup-shaped component 50 cracks, deforms, or melts, while the side wall 52 remains. Therefore, the hot particles generated by the combustion of the propellant 59 flow towards the top plate 21, and the flame flowing into the combustion chamber 60 is squeezed between the cup-shaped component 50 and the top plate 21. As a result, all the gas generating agents 61 adjacent to the cup-shaped component 50 are not ignited simultaneously at one time, and the combustion diffusion of the gas generating agents 61 is centered between the ignition chamber 57 and the top plate 21.

[0111] As the top wall 51 of the cup-shaped component 50 cracks, deforms, or melts, the thin-walled portion 52a cracks as a second stage. Here, the cracking of the side wall 52 proceeds along the length of the radially arranged weak portions 55 provided on the top wall 51. In the thin-walled portion 52a, the cracking proceeds axially downwards in the side wall 52, but stops after reaching the middle (the connection between the thin-walled portion 52a and the thick-walled portion 52b). Therefore, the hot particles generated by the combustion of the propellant 59 also flow into the combustion chamber 60 from this cracked portion. As a result, the flame spreads to the gas generator 61 between the thin-walled portion 52a and the filter 90, and then the flame spreads to the gas generator 61 between the thick-walled portion 52b and the filter 90.

[0112] Therefore, by providing a vulnerable part 55, a non-vulnerable part 56, a thin-walled part 52a, and a thick-walled part 52b on the cup-shaped component 50, and by appropriately adjusting the position and size of these vulnerable parts 55, non-vulnerable parts 56, thin-walled parts 52a, and thick-walled parts 52b, it is possible to prevent the gas generator 61 from burning rapidly and to intentionally delay its combustion. It is also possible to easily optimize the gas output according to specifications, for example, to make the gas output last for a specified time.

[0113] Furthermore, when the side wall portion 52 of the cup-shaped component 50 is constructed as a thin wall, the impact of the cup-shaped component 50 breaking, deforming, or melting due to the combustion of the propellant 59 is applied to the filter 90, posing a risk of damage to the filter 90. However, by constructing a portion (thick-walled portion 52b) of the side wall portion 52 of the cup-shaped component 50 as thick as in the disc-shaped gas generator 100 of the present invention, and providing a vulnerable portion 55 on the top wall portion 51, in the initial stage of the cup-shaped component 50 breaking, deforming, or melting, the hot particles will move towards the top plate portion 21, thereby mitigating the impact applied to such a filter 90 and preventing damage before it occurs.

[0114] Furthermore, by adopting the above structure, since the top wall 51 instantly cracks, deforms or melts from the moment of ignition, the gas generating agent 61 between the top wall 51 and the top plate 21 immediately combusts, so there is no delay in gas output, the internal pressure inside the gas generator also increases rapidly, and deviations in output characteristics can also be prevented.

[0115] As the pressure inside the casing rises due to the combustion of the gas generator 61, the sealing strip 24 that closes the gas outlet 23 on the upper side casing 20 cracks, and gas is ejected out of the casing through the gas outlet 23. The ejected gas is introduced into the interior of the airbag adjacent to the disc-shaped gas generator 100, causing the airbag to inflate and deploy.

[0116] Here, whether the vulnerable part 55 and the thin-walled part 52a of the cup-shaped component 50 will successively break, deform or melt due to the propagation of thrust generated by the operation of the igniter 40 is determined by the mechanical strength (thickness, material, shape, etc.) of the cup-shaped component, the output of the igniter 40, the distance between the ignition part 41 and the cup-shaped component and the vulnerable part 55, and the density of the propellant 59 filled in the ignition chamber.

[0117] In order to utilize the pressure and temperature rise in the ignition chamber accompanying the combustion of the propellant 59 to cause the vulnerable part 55 and the thin-walled part 52a of the cup-shaped component 50 to crack, deform, or melt in sequence, various adjustments can be made to the mechanical strength (thickness, material, shape, etc.) of the cup-shaped component 50, the output of the igniter 40, the distance between the ignition part 41 and the vulnerable part 55 of the cup-shaped component 50, and the density of the propellant 59 filling the ignition chamber. As mentioned above, this can be achieved relatively easily, especially by making the components of the cup-shaped component 50 made of ferrous metal materials such as iron or stainless steel.

[0118] Furthermore, in either case, it is preferable that the mechanical strength of the vulnerable portion 55 of the cup-shaped member 50 is lower than that of the sidewall portion 52 of the cup-shaped member 50. As a method to make the vulnerable portion 55 of the cup-shaped member 50 more vulnerable than the sidewall portion 52 of the cup-shaped member 50, it is conceivable to adjust their thickness, use different materials, or work on their shape, etc.

[0119] With this configuration, the vulnerable portion 55 can be more easily fractured, deformed, or melted before the thin-walled portion 52a of the cup-shaped member 50 fractures, deforms, or melts. However, if the vulnerable portion 55 can be fractured, deformed, or melted before the thin-walled portion 52a of the cup-shaped member 50 fractures, deforms, or melts, then the vulnerable portion 55 and the thin-walled portion 52a of the sidewall portion 52 of the cup-shaped member 50 can also have the same level of mechanical strength.

[0120] As described above, according to the embodiments of the present invention, a disc-shaped gas generator 100 can be provided, which can improve the mechanical strength of the cup-shaped member 50 and can stably control the size of the breakage (fracture) of the cup-shaped member 50. Furthermore, since the size of the breakage of the cup-shaped member 50 is stable (fracture area is homogenized), a disc-shaped gas generator 100 that can achieve the desired performance while reducing the amount of propellant 59 can be formed.

[0121] Furthermore, by promoting the combustion of the ignition propellant 59, the combustion of the gas generator 61 can be initiated earlier. As a result, the time from the moment the igniter starts operating to the moment gas begins to be ejected externally through the gas outlet 23 can be shortened compared to the past. In addition, by adding the weak portion 55 and the thin-walled portion 52a to the cup-shaped component 50, the fracture area can be homogenized. Although the component processing is increased, the amount of ignition propellant 59 can be significantly reduced, and the time from the moment the igniter starts operating to the moment gas begins to be ejected externally through the gas outlet 23 can be shortened at a low cost.

[0122] In addition, by reducing the amount of propellant 59, the volume of the cup-shaped component 50 can be made smaller than before, thus enabling weight reduction by optimizing the volume of the disc-shaped gas generator 100.

[0123] Furthermore, by reducing the amount of ignition charge 59, the gas temperature decreases, which in turn reduces the cooling capacity of the filter 90. As a result, the filter 90 can also be made lighter.

[0124] (Verification Experiment)

[0125] Next, a disc-shaped gas generator with the same structure as disc-shaped gas generator 100 was fabricated. Verification tests were conducted to observe changes in the shape and size of the cup-shaped component during a 60L chamber test. The 60L chamber test refers to a test in which a disc-shaped gas generator with a cup-shaped component (specifically, refer to Examples 1-3 below) was conditioned at -40℃±2℃ for at least 4 hours, then placed in a 60L sealed chamber and operated, with the pressure rise measured over time. In this verification test, the gas pressure was measured over time from the moment the igniter started operating until 100ms. Furthermore, the number of moles of gas generated by the gas generating agent in each disc-shaped gas generator was 2 mol, and the amount of propellant filled into the cup-shaped component was 1.2g. Additionally, the cup-shaped component in this verification test was made of aluminum alloy.

[0126]

Example 1

[0127] For a conventional gas generator (hereinafter referred to as a conventional gas generator) with a certain thickness (1 mm) of cup-shaped component (specification name: stepless), and a gas generator (hereinafter referred to as the gas generator of the present invention) with the same structure as the gas generator 100, which has a thin-walled portion with a thickness of 0.5 mm, an axial length of 5 mm, a thick-walled portion with a thickness of 1 mm, and a cup-shaped component with a thick-walled portion with an axial length of 15 mm, the above-described verification test was performed twice. Furthermore, the vulnerable portion in each cup-shaped component is the same as the vulnerable portion 55 in the above embodiment, with a slit depth of 0.6 mm (remaining thickness of 0.4 mm) and a width of 3 mm. In addition, the axial length of the cup-shaped components in each gas generator is the same. Furthermore, other conditions are the same for both the conventional gas generator and the gas generator of the present invention.

[0128] Figure 4 The results of verification tests for existing gas generators and the gas generator of the present invention are shown. Additionally, t1 is the time until gas output is detected, and Pmax is the maximum pressure inside the chamber.

[0129] In the gas generator of the present invention, such as Figure 4As shown in (1) and (2), both verification tests revealed that from the moment the igniter began to operate, not only was a higher gas output obtained in a relatively early stage, but the same pressure change also occurred. That is, it can be seen that in the gas generator of the present invention, the cup-shaped component can stably perform satisfactory gas output performance.

[0130] In contrast, in existing gas generators, Figure 4 In the verification test shown in (3), although it was able to achieve the same gas output performance as the gas generator of the present invention, Figure 4 In the verification test shown in (4), the time until gas output was detected was longer than... Figure 4 The verification tests (1) to (3) were delayed and could not be passed. Figure 4 The gas output process is as described in (1) to (3). That is, it can be seen that in the existing gas generator structure, each gas generator sometimes deviates during the gas output process.

[0131] Therefore, it can be seen that the gas generator of the present invention can stably and satisfactorily perform gas output performance compared with existing gas generators.

[0132] (Example 2)

[0133] In the gas generator of the present invention, which is the same as in Example 1, a cup-shaped component with an axial height of 20 mm, a thin-walled portion thickness of 0.5 mm, a slit depth of 0.6 mm (with a remaining thickness of 0.4 mm) and a width of 3 mm, and a thickness of 1 mm in other parts (see Figure 1) is used. Figure 5 A) Without changing its internal volume, the axial length Pmm of the thin-walled section was changed to (1) 5mm, (2) 8mm, and (3) 11mm respectively. Under the same 60L box test as in Example 1, a verification test was conducted to determine the gas output. In addition, other conditions for each gas generator were the same. Figure 5 (b) indicates the results of this verification test.

[0134] It can be seen that in the gas generator of this embodiment, such as Figure 5 As shown in (b), even if Figure 5 The axial length Pmm of the thin-walled portion of the cup-shaped component in (a) varies to (1) 5mm, (2) 8mm, and (3) 11mm, and can also achieve the same satisfactory gas output performance as in Example 1.

[0135] (Example 3)

[0136] In the gas generator of the present invention, which is the same as in Example 1, a cup-shaped component (see reference) has an axial height of 20 mm, an axial length of 5 mm for the thin-walled portion, a slit depth of 0.6 mm (with a remaining thickness of 0.4 mm) and a width of 3 mm for the vulnerable portion, and a thickness of 1 mm for the other portions. Figure 6 A) Without changing its internal volume, the thickness Qmm of the thin-walled section was varied to (1) 0.4mm, (2) 0.5mm, (3) 0.6mm, and (4) 0.7mm, respectively. The same 60L box test as in Example 1 was conducted to verify the gas output. In addition, other conditions for each gas generator were the same. Figure 6 (b) indicates the results of this verification test.

[0137] It can be seen that in the gas generator of this embodiment, such as Figure 6 As shown in (b), even if Figure 6 The thickness Qmm of the thin-walled portion of the cup-shaped component in (b) varies to (1) 0.4mm, (2) 0.5mm, (3) 0.6mm, and (4) 0.7mm, respectively, and can also achieve satisfactory gas output performance that is approximately the same as that in Examples 1 and 2.

[0138] (variant examples, etc.)

[0139] Hereinafter, variations of the embodiments of the present invention will be described. Unless otherwise specified, parts with the same function will be referred to by the same name. In addition, in each variation, parts that are the same as those in the above embodiments will sometimes be represented by the same two digits unless otherwise specified, and their description will be omitted.

[0140] Similar to the disc gas generator 100 of this embodiment, the cup-shaped component 50 in the embodiments of the present invention can also be applied to a disc gas generator equipped with two igniters, referred to as dual gas generators, or to other gas generators.

[0141] Furthermore, the vulnerable portion 55 of the cup-shaped component 50 is not limited to... Figure 2 The situation is illustrated. For example, the slits constituting the vulnerable part 55 can be arranged radially, or they can be composed of several slits. For example, the vulnerable part can also have slits arranged in a cross or asterisk shape when viewed from above.

[0142] Furthermore, the shape of the vulnerable portion 55 is not limited to the shapes described above and can be any shape. For example, an annular protrusion can be provided by making a portion of the non-vulnerable portion 56 bulge towards the top wall portion 51, or the entire vulnerable portion 55 can be bent in a way that creates a concave portion. Alternatively, multiple protrusions or concave portions can be provided on the vulnerable portion 55 in a dotted or row-like pattern. Furthermore, circular or annular vulnerable portions 55 can be provided on the top wall portion 51.

[0143] In addition, the slit of the aforementioned vulnerable part 55 may also be continuously extended to the surface (outer wall) of the thin-walled part 52a of the side wall part 52.

[0144] In addition, depending on the purpose, it can also be applied Figure 7 The cup-shaped component 150 shown replaces the cup-shaped component 50. The main difference of the cup-shaped component 150 is that, unlike the cup-shaped component 50 which has a slit (vulnerable portion) formed around its entire circumference, the cup-shaped component 150 does not have a slit (vulnerable portion) formed around its entire circumference. This will be explained in detail below. In addition, in the same parts as in the above embodiment, the same two digits are sometimes used, and their descriptions are omitted.

[0145] The vulnerable part 155, viewed circumferentially, is biasedly positioned by being set between specific angles. Here, the area where the vulnerable part is set at an angle of less than half a circumference (angle of 180°) when viewed from the axial upward side is called the vulnerable part presence area, and the area where no vulnerable part is set at an angle of more than half a circumference (angle of 180°) when viewed from the axial upward side is called the vulnerable part non-present area. Figure 7 In the presence of the aforementioned vulnerable region 151a and the aforementioned vulnerable region 151b, the vulnerable region 151a experiences cracking, deformation, or melting of the cup-shaped component before the vulnerable region 151b, thus allowing the hot particles generated by the combustion of the propellant to flow directionally into the combustion chamber.

[0146] With this configuration, not only can the effects described in the above embodiments be obtained, but also the vulnerable portion 155 and the thin-walled portion 152a more reliably break, deform, or melt when the igniter is operating, thus effectively promoting the combustion of the propellant. Furthermore, since the vulnerable portion 155, which is unevenly distributed at 180° intervals within the thin-walled portion 152a, breaks, deforms, or melts first, the direction in which the combustion gases of the propellant flow into the combustion chamber can be directional. Additionally, this configuration can also be applied to a disc gas generator equipped with two igniters, referred to as dual-chargers.

[0147] In addition, Figure 7In this embodiment, the slits of the vulnerable parts are arranged radially from the center to three locations at an angle of 60°, but this is not a limitation. For example, there may be two roughly V-shaped slits of vulnerable parts arranged at an angle of 60°, or there may be slits of vulnerable parts arranged radially from the center to four or more locations at an angle of 30°. In the above embodiments and variations of the present invention, the upper and lower side shells are illustrated as being formed by a stamped product formed by stamping a metal part, but this is not necessarily the case. The upper and lower side shells may also be formed by a combination of stamping and other processing (forging, deep drawing, cutting, etc.), or they may be formed solely by the other processes described above.

[0148] Furthermore, in the above-described embodiments and variations of the present invention, a case in which a protruding cylindrical portion is provided on the lower side housing is illustrated, but of course, the present invention can also be applied to a gas generator with a structure that does not have such a protruding cylindrical portion.

[0149] Furthermore, in the embodiments and variations thereof described above, while examples of cup-shaped components are illustrated where, upon ignition of the propellant by an igniter, a component is used that cracks, deforms, or melts due to pressure rise or heat conduction within its internal space, other cup-shaped components with different structures can also be used. Specifically, as a cup-shaped component, a structure may be used where an opening is pre-formed in a component with high mechanical strength, such as a stainless steel alloy, and the opening is sealed with a sealing strip, thereby breaking the seal during operation.

[0150] Furthermore, as a variation of the above-described embodiment, the following can be cited: Figures 8-11 The gas generator and cup-shaped component are shown. Hereinafter, the gas generator and cup-shaped component of each modified example will be described, focusing on the differences from the above embodiment.

[0151] Figure 8 The gas generator in (a) differs from the embodiment described above in that the upper end of the upright portion 273 of the lower support member 270 is pressed into the thick-walled portion 252b of the cup-shaped member 250, and an upper support member 280 with its base 281 side facing the lower side is used, without the use of cushioning material. Furthermore, the side wall portion 282 of the upper support member 280 may or may not abut against the inner wall of the filter 290.

[0152] Here, Figure 8 (b) shows Figure 8(a) shows a step in the manufacturing process of the gas generator (before pressing the upper side housing 220 into the lower side housing 210). Note that before pressing the upper side housing 220 into the lower side housing 210 (before pressing the upper end of the upright portion 273 of the lower support member 270 into the thick-walled portion 252b of the cup-shaped member 250), the relationship is such that the outer diameter of the thin-walled portion 252a ≦ the inner diameter of the upper end of the upright portion 273 of the lower support member 270 < the outer diameter of the thick-walled portion 252b. Therefore, in Figure 8 In (b), the upper end of the upright portion 273 of the lower support member 270 is embedded in the thin-walled portion 252a of the cup-shaped member 250, but is stopped by the upper end of the thick-walled portion 252b, so that it will not naturally move downward from the upper end of the thick-walled portion 252b. This prevents the lower support member 270 from being tilted or moved radially during manufacturing, thereby enabling the smooth filling of the gas generating agent 261 into the gas generator 200.

[0153] In addition, such as Figure 8 As shown in (b), when the gas generating agent 261 is filled into the gas generator 200 and the upper side housing 220 is pressed into the lower side housing 210, the upper end of the upright portion 273 of the lower support member 270 is pressed into the thick-walled portion 252b of the cup-shaped member 250 by the gas generating agent 261 pressed by the upper support member 280. Thus, the gas generating agent 261 is fixed within the space surrounded by the lower support member 270, the upper support member 280, and the filter 290. Furthermore, since the lower support member 270 is pressed and fixed onto the thick-walled portion 252b of the cup-shaped member 250, it will not move inside the gas generator 200 even if the gas generator 200 vibrates.

[0154] Therefore, according to this modified example, not only can the same effects as the above-described embodiments be obtained, but also, compared with the above-described embodiments, the number of parts can be reduced since no cushioning material is required. In addition, since the lower support member 270 does not need to be pre-fixed, and the above-described pressing-in fixing is performed when the upper side housing 220 is pressed into the lower side housing 210, the cost can be reduced by simplifying the manufacturing process.

[0155] Next, for Figure 9 The gas generator shown will be described below. The gas generator 300 differs from the embodiment described above in that a cup-shaped component 350 is used instead of the cup-shaped component 50 and the lower support component 70. Here, Figure 10 (a) shows a perspective view of the cup-shaped component 350.

[0156] To enable the cup-shaped component 350 to simultaneously function as both the cup-shaped component 50 and the lower support component 70 of the above embodiment, a standing portion 373, a base portion 371, and an abutment portion 372 corresponding to the lower support component 70 of the above embodiment are integrally extended sequentially from the flange portion 362 of the cup-shaped component 350. Furthermore, the cup-shaped component 350 is fixed to the inner covering portion 331 and the gas generating agent 361 filled within the filter 390. Thus, as... Figure 9 As shown in (b), when the cup-shaped component 350 is in operation, the weak part 355 and the thin-walled part 352a break, deform or melt in sequence, just like in the above embodiment, and a large number of hot particles generated by the combustion of the propellant 359 flow into the combustion chamber 360 in advance.

[0157] According to this modified example, not only does it achieve the same effect as the above-described embodiment, but compared to the above-described embodiment, before operation, the cup-shaped component 350 and the inner cover 331 can be fixed together with the gas generating agent 361, and after operation, together with the inner cover 331, the abutment portion 372 can further prevent the cup-shaped component 350 from axially moving towards the housing of the gas generator 300. Figure 9 The movement is in the vertical direction of the paper surface. Furthermore, according to this modified example, since the cup-shaped member 350 integrates the cup-shaped member 50 and the lower support member 70 of the above embodiment, the number of parts can be reduced compared to the above embodiment.

[0158] Next, for Figure 11 The gas generator shown will be described below. The gas generator 400 includes... Figure 10 The cup-shaped component shown in (b) differs from the embodiment described above in that a cup-shaped component 450 is used instead of the cup-shaped component 50 and the lower support component 70. Here, Figure 10 (b) shows a perspective view of the cup-shaped component 450.

[0159] The cup-shaped component 450 has a top wall portion 451 instead of the top wall portion 351 of the cup-shaped component 350 in the modified example described above. This top wall portion 451 has a generally circular, thinner, and less dense portion 455. Furthermore, the cup-shaped component 450 is fixed to the inner cover portion 431 and the gas generator 361 filled within the filter 490. Thus, as... Figure 11 As shown in (b), when the cup-shaped component 450 is in operation, the vulnerable part 455 (the thin-walled part 452a also depends on the type and amount of the propellant 459 and / or the thickness of the thin-walled part 452a) cracks, deforms or melts, and a large number of hot particles generated by the combustion of the propellant 459 flow into the combustion chamber 460 in advance.

[0160] According to this modified example, not only does it achieve the same effect as the above-described embodiment, but compared to the above-described embodiment, before operation, the cup-shaped component 450 and the inner cover 431 can be fixed together with the gas generating agent 461, and after operation, together with the inner cover 331, the abutment portion 372 can further prevent the cup-shaped component 450 from axially moving towards the housing of the gas generator 400. Figure 11 The movement is in the vertical direction of the paper surface. Furthermore, according to this modified example, since the cup-shaped member 450 integrates the cup-shaped member 50 and the lower support member 70 of the above embodiment, the number of parts can be reduced compared to the above embodiment.

[0161] In addition, alternative Figure 11 The cup-shaped component 450 in the gas generator can also be a cup-shaped component 550 that does not have a portion equivalent to the thin-walled portion 452a in the side wall portion 552 (see reference). Figure 10 (c)).

[0162] Furthermore, the characteristic structures shown in the above-described embodiments and variations of the present invention can of course be combined with each other within the scope permitted by reference to the spirit of the present invention.

[0163] In summary, the embodiments and variations disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the scope of the claims and includes all modifications within the meaning and scope equivalent to the description in the claims.

[0164] Explanation of reference numerals in the attached figures

[0165] 10, 210, 310, 410 lower side housing

[0166] 11, 211, 311, 411 Base plate

[0167] 12, 212, 312, 412 Peripheral sections

[0168] 13, 213, 313, 413 Protruding cylindrical portion

[0169] 14, 214, 314, 414 Recesses

[0170] 15, 215, 315, 415 openings

[0171] 20, 220, 320, 420 Upper side shell

[0172] Top plate section 21, 221, 321, 421

[0173] 22, 222, 322, 422 Peripheral sections

[0174] Gas ejection outlets 23, 223, 323, and 423

[0175] 24, 224, 324, 424 sealing tape

[0176] 28, 228, 328, 428 gaps

[0177] 30, 230, 330, 430 retaining sections

[0178] Inner covering parts of 31, 231, 331, and 431

[0179] 32, 232, 332, 432 Outer Covering

[0180] 33, 232, 332, 432 Connecting parts

[0181] Female connectors of types 34, 234, 334, and 434

[0182] 40, 240, 340, 440 Igniters

[0183] 41, 241, 341, 441 Ignition Section

[0184] 42, 242, 342, 442 terminal pins

[0185] Cup-shaped parts in sizes 50, 150, 250, 350, 450, and 550.

[0186] 51, 151, 251, 351, 451, 551 top wall

[0187] Side wall sections 52, 152, 252, 282, 352, 452, 552

[0188] Thin-walled sections 52a, 152a, 252a, 352a, 452a

[0189] Thick-walled sections: 52b, 152b, 252b, 352b, 452b

[0190] 55, 155, 255, 355, 455, 555 Vulnerable Department

[0191] 56, 156, 256, 356 Non-vulnerable sectors

[0192] Fire transfer rooms 57, 257, 357, and 457

[0193] 59, 259, 359, 459 ignition source

[0194] 60, 260, 360, 460 Combustion Chambers

[0195] 61, 261, 361, 461 Gas Generator

[0196] Flange portions of 62, 162, 262, 362, 462, and 562

[0197] 70, 270 Lower support components

[0198] 71, 81, 271, 371, 471, 281, 381, 481, 571 (Base)

[0199] 72, 82, 272, 372, 472, 382, ​​482, 572 Contact part

[0200] 73, 273, 373, 473, 573 (Establishment Department)

[0201] Upper support components for 80, 280, 380, and 480 mm

[0202] 85, 385, 485 cushioning materials

[0203] 90, 290, 390, 490 filters

[0204] 100, 200, 300, 400 disc gas generators

[0205] 151a Vulnerable area

[0206] 151b Vulnerable area non-existent region

Claims

1. A gas generator, comprising: A short-sized cylindrical shell is composed of a cylindrical peripheral wall portion with a gas outlet, a top plate portion that closes one axial end of the peripheral wall portion, and a bottom plate portion that closes the other axial end of the peripheral wall portion, and contains a combustion chamber containing a gas generating agent inside. An igniter comprising an ignition part mounted on the base plate and housing an ignition propellant for ignition during operation; and A cup-shaped component, which contains a ignition chamber housing a propellant, is composed of a single, bottomed cylindrical component protruding into the combustion chamber, with the interior space of the ignition chamber facing the ignition unit. At least a portion of the top wall of the cup-shaped component is provided with a thin-walled vulnerable portion, and the side wall portion of the cup-shaped component has a higher mechanical strength than the vulnerable portion that divides the ignition chamber and the combustion chamber. The side wall portion includes a thin-walled portion disposed on the side of the top wall portion, and a thick-walled portion extending axially from the thin-walled portion to the side opposite to the top wall portion. The vulnerable part is configured opposite to the ignition part and has the mechanical strength to cause the cup-shaped component to crack, deform, or melt before the sidewall part when the igniter is activated. The thin-walled portion has the mechanical strength to fracture, deform, or melt if the fracture, deformation, or melting of the weak portion progresses to the thin-walled portion. The mechanical strength of the thick-walled portion of the sidewall of the cup-shaped component is higher than that of the thin-walled portion, and the mechanical strength of the thin-walled portion is higher than that of the weak portion disposed on at least a portion of the top wall of the cup-shaped component and dividing the ignition chamber and the combustion chamber.

2. The gas generator according to claim 1, wherein, The vulnerable portion disposed on the top wall of the cup-shaped component is composed of a wall that is thinner than the side wall of the cup-shaped component.

3. The gas generator according to claim 1, wherein, The top wall of the cup-shaped component consists of a region where a fragile part initially cracks, deforms, or melts, starting from the fragile part, due to the combustion of the propellant accompanying the operation of the igniter, and a region where a fragile part does not exist, after deformation in the region where the fragile part exists and a predetermined time has elapsed.

4. The gas generator according to claim 2, wherein, The top wall of the cup-shaped component consists of a region where a fragile part initially cracks, deforms, or melts, starting from the fragile part, due to the combustion of the propellant accompanying the operation of the igniter, and a region where a fragile part does not exist, after deformation in the region where the fragile part exists and a predetermined time has elapsed.

5. The gas generator according to claim 1, wherein, The vulnerable part has a slit shape that is radially arranged from the center on the top wall.

6. The gas generator according to claim 2, wherein, The vulnerable part has a slit shape that is radially arranged from the center on the top wall.

7. The gas generator according to claim 3, wherein, The vulnerable part has a slit shape that is radially arranged from the center on the top wall.

8. The gas generator according to claim 1, wherein, The cup-shaped component is made of metal.

9. The gas generator according to any one of claims 1 to 8, characterized in that, It also includes a filter arranged circumferentially on the inner side of the housing; as well as The support member has an annular plate-shaped base portion disposed along the inner bottom surface of the base plate portion, an abutting portion abutting against the inner circumferential surface of the end portion of the filter disposed on the base plate portion side, and a cylindrical erecting portion erected vertically from the base portion toward the top plate portion side. The support member is held on the cup-shaped member by pressing the upright portion into the thick-walled portion of the cup-shaped member.

10. The gas generator according to any one of claims 1 to 8, characterized in that, It also includes a filter arranged circumferentially inside the housing. The cup-shaped component also has an annular plate-shaped base disposed along the inner bottom surface of the base plate portion, an abutting portion that abuts against the inner circumferential surface of the end portion of the filter on the base plate portion side, and a cylindrical upright portion disposed vertically from the base portion toward the top plate portion side. The upright portion extends integrally from the side wall portion of the cup-shaped component.

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