JP7130076B2 - gas generator - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas generator incorporated in an occupant protection device for protecting an occupant in the event of a vehicle collision, and more particularly to a gas generator incorporated in an airbag device installed in an automobile or the like.

2. Description of the Related Art Conventionally, from the viewpoint of protecting occupants of automobiles and the like, airbag devices, which are occupant protection devices, have been widely used. Airbag systems are installed to protect passengers from the impact that occurs in the event of a vehicle collision. By inflating and deploying the airbag instantaneously in the event of a vehicle collision, the airbag acts as a cushion for the passenger. It accepts the body.

The gas generator is incorporated in this airbag system, and when a vehicle or other vehicle collides, the igniter is ignited by the energization of the control unit, and the flame generated in the igniter burns the gas generating agent to instantly generate a large amount of gas. , the device that inflates and deploys the airbag.

There are various types of gas generators, but as a gas generator that can be suitably used for a driver side air bag device, a passenger side air bag device, etc., a short, substantially cylindrical shape with a relatively large outer diameter is used. As a gas generator that can be suitably used for side airbag devices, curtain airbag devices, knee airbag devices, etc., there is a long cylinder-shaped gas generator with a relatively small outer diameter. there is a vessel

Among them, the disc-type gas generator has a short cylindrical housing closed at both ends in the axial direction. The inside of the housing is filled with the gas generating agent so as to surround the device, and the filter is housed inside the housing so as to surround the gas generating agent.

Here, in the disk-type gas generator, the housing is often constructed by combining a pair of shell members having a substantially cylindrical shape with a bottom. One of these shell members is provided with a flange portion which is a portion for fixing the disk-shaped gas generator to an external member (for example, a retainer provided in an airbag device).

Generally, in a gas generator, it is important to stably and sustainably burn the gas generating agent during operation. In order to stably and sustainably burn the gas generating agent, it is necessary to place the gas generating agent under a predetermined high-pressure environment. Its design is such that the pressure in the space inside the housing increases to a considerable extent during operation by reducing the size to the desired size.

However, the output characteristics of a gas generator are affected by the surrounding environment in which the gas generator is placed, and particularly depend on the ambient temperature, with the output characteristics becoming stronger in high-temperature environments and weaker in low-temperature environments. There is a tendency. That is, in a hot environment, the gas will come out faster and stronger, and in a cold environment, the gas will come out slower and weaker. Therefore, especially in a low temperature environment, opening the gas outlet tends to cause a large drop in the pressure inside the housing, hindering the sustained combustion of the gas generating agent and causing a shortage of gas output. It may occur.

For the purpose of reducing the performance difference in gas output due to the environmental temperature, for example, International Publication No. 2015/163290 (Patent Document 1) discloses that a plurality of gas ejection ports provided in a housing have opening pressures. Gas generators configured to include different are disclosed.

In the gas generator constructed in this manner, the plurality of gas ejection ports are opened step by step as the pressure in the space inside the housing increases. Therefore, the pressure inside the housing drops significantly, especially in a low-temperature environment, compared to a gas generator configured so that all gas ejection ports are opened at once as the pressure in the space inside the housing rises. can be prevented from occurring.

Therefore, with the gas generator having this configuration, it is possible to continuously burn the gas generating agent in any temperature environment from a high temperature environment to a low temperature environment. It is possible to reduce the difference in gas output performance.

10 to 12 of the above Patent Document 1, a plurality of gas ejection ports having three stages of release pressure are provided on the peripheral wall of the housing, thereby reducing the space inside the housing during operation. A disk-type gas generator is disclosed in which a plurality of gas ejection ports are opened in three steps as the pressure rises. Here, in consideration of the general specifications required for disk-type gas generators, it is preferable to set the plurality of gas ejection ports to be opened in three steps.

WO2015/163290

On the other hand, in recent years, there is a strong demand for downsizing and weight reduction of gas generators. In order to reduce the size and weight of the gas generator, it is effective to reduce the thickness of the housing, which is a pressure container. It becomes impossible to secure.

In particular, gas generation in which a plurality of gas ejection ports including those having different opening areas are provided in the housing so that the plurality of gas ejection ports are opened in stages during operation. It is an important issue how to reduce the size and weight of the device while ensuring the pressure resistance performance.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the problems described above, and provides a gas generator having a housing provided with a plurality of gas ejection ports, including those having opening areas different from each other. The purpose is to reduce the size and weight while ensuring the same.

A gas generator according to the present invention comprises a housing, a gas generant and an igniter. The housing has a peripheral wall portion, a top plate portion and a bottom plate portion, and both axial ends of the peripheral wall portion are closed by the top plate portion and the bottom plate portion. The gas generating agent is arranged inside the housing and generates gas by burning. The igniter is attached to the housing and is used to burn the gas generating agent. The housing is configured by combining and joining a plurality of shell members, and one of the plurality of shell members includes a tubular portion forming at least a part of the peripheral wall portion, and the and a flange portion continuously extending radially outward from one end in the axial direction of the cylindrical portion. The cylindrical portion is provided with a plurality of gas ejection ports including those having opening areas different from each other, and the flange portion is the distance from the axis of the cylindrical portion to the outer edge of the flange portion. is configured to have a non-uniform shape. In the gas generator according to the present invention, a line perpendicular to the axis of the tubular portion is drawn from the outer edge of the flange portion, which is the position farthest from the axis of the tubular portion. When drawn, none of the plurality of gas ejection ports are arranged at a position on a plane that includes the perpendicular and the axis of the cylindrical portion, and the perpendicular is arranged so as to sandwich the perpendicular. The pair of gas ejection openings arranged closest to the . Here, there are a plurality of maximum outer shape positions along the circumferential direction of the cylindrical portion, and the above condition is satisfied at each of the portions corresponding to the plurality of maximum outer shape positions.

In the gas generator according to the present invention, it is preferable that the flange portion is provided with a through hole for fixing the gas generator to an external member. The distance from the axis of the cylindrical portion to the outer edge of the flange portion is larger in a portion of the flange portion provided with the through hole than in a portion of the flange portion not provided with the through hole. preferably.

In the gas generator according to the present invention, it is preferable that the plurality of gas ejection ports are arranged in a row along the circumferential direction of the cylindrical portion.

In the gas generator according to the present invention, the housing includes, as the plurality of shell members, a bottomed cylindrical upper shell that constitutes the top plate portion and the peripheral wall portion near the top plate portion. and a bottomed cylindrical lower shell that constitutes the bottom plate portion and the peripheral wall portion near the bottom plate portion. In that case, the tubular portion provided with the plurality of gas ejection ports is defined by the upper shell of the portion forming the peripheral wall portion closer to the top plate portion, and the flange extends from the bottom plate portion side end portion of the upper shell of the portion forming the peripheral wall portion near the top plate portion. In this case, the lower shell in the portion forming the peripheral wall portion closer to the bottom plate portion is inserted into the upper shell portion forming the peripheral wall portion closer to the top plate portion. , the upper shell and the lower shell are preferably combined. Furthermore, in that case, it is preferable that the igniter is assembled to the lower shell of the portion forming the bottom plate portion.

In the gas generator according to the present invention, it is preferable that the plurality of gas ejection ports are composed of a plurality of sets of gas ejection port groups. In that case, the plurality of groups of gas ejection ports are evenly spaced along the circumferential direction of the tubular portion so as to have rotational symmetry with an angle of 120° or less around the axis of the tubular portion. One set or two or more sets of first gas ejection port groups consisting of a plurality of first gas ejection ports having the same first opening pressure, and 120 [° ] A set or two of a plurality of second gas ejection ports having the same second opening pressure, which are evenly arranged along the circumferential direction of the cylindrical portion so as to have rotational symmetry with the following angles: The group of at least two second gas ejection ports are evenly arranged along the circumferential direction of the tubular portion so as to have rotational symmetry at an angle of 120° or less about the axis of the tubular portion. It is preferable to have only one set or two or more sets of third gas ejection port groups each composed of a plurality of third gas ejection ports having the same third opening pressure. In that case, it is preferable that the second release pressure is higher than the first release pressure, and the third release pressure is higher than the second release pressure. Furthermore, in that case, it is preferable that the plurality of gas ejection ports are arranged so as not to overlap each other in the circumferential direction of the tubular portion.

Here, the above-described gas ejection port group is determined so that one set of gas ejection port group is composed of as many gas ejection ports as possible. That is, for example, when four gas ejection ports having the same opening pressure are provided in the peripheral wall portion of the housing along the circumferential direction, these are arranged with 180[°] rotational symmetry. Two sets of gas ejection port groups in total: a gas ejection port group consisting of one gas ejection port and a gas ejection port group consisting of two gas ejection ports arranged with 180[°] rotational symmetry. Although it can be considered to be configured, it should not be considered as such, and in this case, it consists of four gas outlets arranged with 90 [°] rotational symmetry It is assumed that it is composed of one set of gas ejection port groups.

In the gas generator according to the present invention, at least one of the plurality of first gas ejection ports, the plurality of second gas ejection ports, and the plurality of third gas ejection ports is , S [mm ² ] is the opening area of one gas ejection port, and C [mm] is the peripheral length of the one gas ejection port. It preferably has a shape that satisfies the condition of 27×S ^0.5 .

In the gas generator according to the present invention, at least one of the plurality of first gas ejection ports, the plurality of second gas ejection ports, and the plurality of third gas ejection ports is Preferably, the opening has an elongated shape in which the width of the opening along the axial direction of the tubular portion is larger than the width of the opening along the circumferential direction of the tubular portion.

According to the present invention, it is possible to reduce the size and weight of a gas generator in which a housing is provided with a plurality of gas ejection ports, including those having different opening areas, while ensuring pressure resistance performance. Become.

1 is a front view of a disk-shaped gas generator according to Embodiment 1 of the present invention; FIG. FIG. 2 is a schematic cross-sectional view of the disk-shaped gas generator shown in FIG. 1; Figure 3 is a cross-sectional view of the upper shell taken along line III-III shown in Figures 1 and 2; 4 is an enlarged view of first to third gas ejection ports shown in FIGS. 1 and 3; FIG. FIG. 5 is a diagram schematically showing how the gas ejection port is opened step by step during operation of the disk-type gas generator according to Embodiment 1 of the present invention. FIG. 5 is a diagram schematically showing the difference in degree of deformation of the main part of the housing during operation between the disk-shaped gas generator according to the comparative example and the disk-shaped gas generator according to Embodiment 1 of the present invention. FIG. 4 is a diagram schematically showing the state in the vicinity of the gas ejection port during operation of the disk-type gas generator according to Embodiment 1 of the present invention; Fig. 2 is a front view of a disk-shaped gas generator according to Embodiment 2 of the present invention; FIG. 9 is a cross-sectional view of the upper shell taken along line IX-IX shown in FIG. 8; FIG. 10 is a diagram schematically showing the degree of deformation of the main part of the housing during operation of the disk-shaped gas generator according to Embodiment 2 of the present invention; FIG. 4 is a cross-sectional view of an upper shell of a disk-shaped gas generator according to Embodiment 3 of the present invention; 12 is an enlarged view of first to third gas ejection ports shown in FIG. 11; FIG. FIG. 11 is a cross-sectional view of an upper shell of a disk-shaped gas generator according to Embodiment 4 of the present invention; 14 is an enlarged view of first to third gas ejection ports shown in FIG. 13; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION 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 disk-type gas generator that is suitably incorporated in an airbag device mounted on a steering wheel or the like of an automobile. In the embodiments shown below, the same or common parts are denoted by the same reference numerals in the drawings, and the description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a front view of a disk-shaped gas generator according to Embodiment 1 of the present invention, and FIG. 2 is a schematic sectional view of the disk-shaped gas generator shown in FIG. First, referring to FIGS. 1 and 2, the configuration of the disk-shaped gas generator 1A according to the present embodiment will be described.

As shown in FIGS. 1 and 2, a disk-shaped gas generator 1A according to the present embodiment has a short, substantially cylindrical housing closed at one end and the other end in the axial direction. In the storage space provided inside the holding portion 30 as internal components, the igniter 40, the cup-shaped member 50, the transfer charge 56, the gas generating agent 61, the lower side support member 70, the upper side support member 80, the cushion It is configured by housing a material 85, a filter 90, and the like. Further, a combustion chamber 60 in which the gas generating agent 61 of the internal components described above is mainly accommodated is located in the accommodation space provided inside the housing.

The housing includes a lower shell 10 and an upper shell 20 as shell members. Each of the lower shell 10 and the upper shell 20 is a press-formed product formed by pressing a rolled metal plate member, for example. As the metal plate-shaped members forming the lower shell 10 and the upper shell 20, for example, metal plates made of stainless steel, iron steel, aluminum alloy, stainless alloy, etc. are used. A so-called high-strength steel sheet that does not cause damage such as breakage even when a tensile stress of [MPa] or less is applied is used.

The lower shell 10 and the upper shell 20 are each formed in a substantially cylindrical shape with a bottom, and a housing is constructed by combining and joining these opening surfaces facing each other. The lower shell 10 has a bottom plate portion 11 and a tubular portion 12 , and the upper shell 20 has a top plate portion 21 , a tubular portion 22 and a flange portion 23 .

The upper end of the tubular portion 12 of the lower shell 10 is press-fitted by being inserted into the lower end of the tubular portion 22 of the upper shell 20 . Further, the tubular portion 12 of the lower shell 10 and the tubular portion 22 of the upper shell 20 are joined together at or near their abutting portions, thereby joining the lower shell 10 and the upper shell 20 together. Fixed. Electron beam welding, laser welding, friction welding, or the like can be suitably used for joining the lower shell 10 and the upper shell 20 .

As a result, the portion of the peripheral wall of the housing near the bottom plate portion 11 is formed by the cylindrical portion 12 of the lower shell 10, and the portion of the peripheral wall of the housing near the top plate portion 21 is formed by the upper portion. It is constituted by the tubular portion 22 of the side shell 20 . One end and the other axial end of the housing are closed by the bottom plate portion 11 of the lower shell 10 and the top plate portion 21 of the upper shell 20, respectively.

The flange portion 23 provided on the upper shell 20 continues radially outward from the bottom plate portion 11 side end of the lower shell 10 , which is one axial end of the cylindrical portion 22 of the upper shell 20 . It is provided so as to extend As a result, the flange portion 23 protrudes radially outward from a midway position in the axial direction of the peripheral wall portion of the housing.

The flange portion 23 is a portion for fixing the disk-type gas generator 1A to an external member (for example, a retainer provided in an airbag device, etc.). A through-hole 25 (see FIG. 3, etc.) is provided at a predetermined position of the flange portion 23 so as to pass therethrough along a direction parallel to the axial direction of the cylindrical portion 22 . A fastening member such as a bolt (not shown) is inserted into the through hole 25, thereby fixing the disk-shaped gas generator 1A to an external member.

As shown in FIG. 2, the bottom plate portion 11 of the lower shell 10 is provided with a projecting cylindrical portion 13 protruding toward the top plate portion 21 at the central portion thereof. A recessed portion 14 is formed in the central portion of the portion 11 . The protruding cylindrical portion 13 is a portion to which the igniter 40 is fixed via the holding portion 30 , and the recessed portion 14 is a portion serving as a space for providing the female connector portion 34 in the holding portion 30 .

The protruding cylindrical portion 13 is formed in a substantially cylindrical shape with a bottom, and has an asymmetrical shape (for example, a D shape, a barrel An opening 15 having a mold shape, oval shape, etc.) is provided. The opening 15 is a portion through which the pair of terminal pins 42 of the igniter 40 are inserted.

The igniter 40 is for generating flame, and includes an igniter 41 and the pair of terminal pins 42 described above. The ignition part 41 contains therein an ignition charge that generates flame by being ignited and burned during operation, and a resistor for igniting the ignition charge. A pair of terminal pins 42 are connected to the ignition portion 41 to ignite the ignition charge.

More specifically, the ignition part 41 includes a cup-shaped squib cup and a base that closes the open end of the squib cup and holds a pair of terminal pins 42 inserted therethrough. A resistor (bridge wire) is attached so as to connect the ends of a pair of terminal pins 42 inserted into the squib cup, and points are placed in the squib cup so as to surround or be adjacent to the resistor. It has a configuration loaded with gunpowder.

Nichrome wire or the like is generally used as the resistor, and ZPP (zirconium/potassium perchlorate), ZWPP (zirconium/tungsten/potassium perchlorate), lead tricinate, or the like is generally used as the igniter. Note that the squib cup and base described above are generally made of metal or plastic.

A predetermined amount of current flows through the resistor via the terminal pin 42 when a collision is detected. When a predetermined amount of current flows through the resistor, Joule heat is generated in the resistor, and the ignition charge starts burning. The high temperature flame produced by the combustion ruptures the squib cup containing the ignition charge. The time from when the current flows through the resistor until the igniter 40 is activated is generally 2 [ms] or less when the nichrome wire is used as the resistor.

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

The holding portion 30 is formed by injection molding (more specifically, insert molding) using a mold. It is formed by applying an insulating fluid resin material to the bottom plate portion 11 so as to reach from a part of the inner surface to a part of the outer surface of the bottom plate portion 11 and solidifying it.

The igniter 40 is inserted from the inside of the lower shell 10 so that the terminal pin 42 is inserted into the opening 15 when the holding portion 30 is molded. It is fixed to the bottom plate portion 11 via the holding portion 30 by pouring the fluid resin material described above so as to fill the space between the bottom plate portion 10 and the bottom plate portion 10 .

As the raw material of the holding portion 30 formed by injection molding, a resin material that is excellent in heat resistance, durability, corrosion resistance, etc. after curing is suitably selected and used. In that case, it is not limited to thermosetting resins represented by epoxy resins, etc., but is represented by polybutylene terephthalate resin, polyethylene terephthalate resin, polyamide resin (for example, nylon 6, nylon 66, etc.), polypropylene sulfide resin, polypropylene oxide resin, etc. It is also possible to use a thermoplastic resin that When these thermoplastic resins are selected as the raw material, it is preferable that these resin materials contain glass fiber or the like as a filler in order to secure the mechanical strength of the holding portion 30 after molding. However, if sufficient mechanical strength can be ensured only by the thermoplastic resin, it is not necessary to add the filler as described above.

The holding portion 30 includes an inner coating portion 31 that partially covers the inner surface of the bottom plate portion 11 of the lower shell 10, an outer coating portion 32 that partially covers the outer surface of the bottom plate portion 11 of the lower shell 10, and a lower A connecting portion 33 is located in the opening 15 provided in the bottom plate portion 11 of the side shell 10 and is continuous with the inner covering portion 31 and the outer covering portion 32, respectively.

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

As a result, the opening 15 is completely embedded by the terminal pin 42 and the holding portion 30, and the airtightness of the space inside the housing is ensured by ensuring the sealing performance in this portion. In addition, since the opening 15 is formed in an asymmetrical shape in plan view as described above, by embedding the opening 15 with the connecting portion 33 , the opening 15 and the connecting portion 33 are connected to the holding portion 30 . It also functions as a detent mechanism for preventing rotation of the bottom plate portion 11 .

A female connector portion 34 is formed at a portion of the holding portion 30 facing the outside of the outer covering portion 32 . The female connector portion 34 is a portion for receiving a male connector (not shown) of a harness for connecting the igniter 40 and a control unit (not shown). is located in a recess 14 provided in the .

A terminal pin 42 of the igniter 40 is disposed in the female connector portion 34 so that a portion near the lower end thereof is exposed. A male connector is inserted into the female connector portion 34 to achieve electrical continuity between the core wires of the harness and the terminal pins 42 .

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

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

Here, as the adhesive to be applied to the bottom plate portion 11 in advance, an adhesive containing a resin material having excellent heat resistance, durability, corrosion resistance, etc. after curing as a raw material is preferably used. Materials containing resins or silicone-based resins as raw materials are particularly preferably used. In addition to the above resin materials, phenolic resins, epoxy resins, melamine resins, urea resins, polyester resins, alkyd resins, polyurethane resins, polyimide resins, polyethylene resins, polypropylene resins, Polyvinyl chloride resin, polystyrene resin, polyvinyl acetate resin, polytetrafluoroethylene resin, acrylonitrile butadiene styrene resin, acrylonitrile styrene resin, acrylic resin, polyamide resin, polyacetal resin, polycarbonate resin, Polyphenylene ether resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polyolefin resin, polyphenylene sulfide resin, polysulfone resin, polyether sulfone resin, polyarylate resin, polyether ether ketone resin , polyamideimide-based resin, liquid crystal polymer, styrene-based rubber, olefin-based rubber, etc. as raw materials can be used as the above-mentioned adhesive.

Here, a configuration example in which the igniter 40 can be fixed to the lower shell 10 by injection molding the holding part 30 made of a resin molded part is illustrated, but the igniter 40 to the lower shell 10 It is also possible to use other alternatives for the fixation of the .

A cup-shaped member 50 is assembled to the bottom plate portion 11 so as to cover the projecting cylindrical portion 13 , the holding portion 30 and the igniter 40 . The cup-shaped member 50 has a substantially cylindrical shape with an open end on the bottom plate portion 11 side, and includes a transfer chamber 55 in which a transfer charge 56 is accommodated. The cup-shaped member 50 protrudes into the combustion chamber 60 containing the gas generating agent 61 so that the transfer chamber 55 provided therein faces the ignition portion 41 of the igniter 40 . positioned to be located.

The cup-shaped member 50 includes a top wall portion 51 and a side wall portion 52 that define the transfer chamber 55 described above, and an extension portion 53 that extends radially outward from the opening end side portion of the side wall portion 52 . have. Extending portion 53 is formed to extend along the inner surface of bottom plate portion 11 of lower shell 10 . Specifically, the extension portion 53 has a shape that is bent along the shape of the inner bottom surface of the bottom plate portion 11 in the portion where the projecting tubular portion 13 is provided and in the vicinity thereof. The directionally outward portion includes a flange-like extending tip 54 .

A distal end portion 54 of the extension portion 53 is arranged between the bottom plate portion 11 and the lower side support member 70 along the axial direction of the housing, thereby extending between the bottom plate portion 11 and the lower side along the axial direction of the housing. It is sandwiched between the support member 70 and the support member 70 . Here, the lower side support member 70 is in a state of being pressed toward the bottom plate portion 11 side by the gas generating agent 61, the cushion material 85, the upper side support member 80, and the top plate portion 21 arranged thereabove. , the cup-shaped member 50 is fixed to the bottom plate portion 11 when the tip portion 54 of the extension portion 53 is pressed toward the bottom plate portion 11 by the lower side support member 70 . As a result, the cup-shaped member 50 is prevented from coming off from the bottom plate portion 11 without using caulking or press-fitting to fix the cup-shaped member 50 .

The cup-shaped member 50 does not have an opening in either the top wall portion 51 or the side wall portion 52, and surrounds a transfer chamber 55 provided therein. When the transfer charge 56 is ignited by the operation of the igniter 40, the cup-shaped member 50 bursts or melts as the pressure rises in the transfer chamber 55 and the conduction of the generated heat. Materials with relatively low mechanical strength are used.

Therefore, as the cup-shaped member 50, a member made of metal such as aluminum or aluminum alloy, thermosetting resin such as epoxy resin, polybutylene terephthalate resin, polyethylene terephthalate resin, or polyamide resin (for example, nylon 6 or nylon 66, etc.), polypropylene sulfide resin, polypropylene oxide resin, and the like.

In addition, the cup-shaped member 50 may be made of a metal member having high mechanical strength such as iron or copper, and has an opening in the side wall portion 52. It is also possible to use the one to which a sealing tape is attached so as to close the opening. Moreover, the fixing method of the cup-shaped member 50 is not limited to the fixing method using the lower support member 70 described above, and other fixing methods may be used.

The transfer charge 56 filled in the transfer charge chamber 55 is ignited by the flame generated by the operation of the igniter 40 and burns to generate thermal particles. The transfer charge 56 must be capable of reliably starting combustion of the gas generating agent 61. Generally, B/KNO ₃ , B/NaNO ₃ , Sr(NO ₃ ) ₂ and the like are used. A composition consisting of metal powder/oxidizing agent represented by , a composition consisting of titanium hydride/potassium perchlorate, a composition consisting of B/5-aminotetrazole/potassium nitrate/molybdenum trioxide, and the like are used.

As the transfer charge 56, a powdery one, a binder molded into a predetermined shape, or the like is used. The shape of transfer charge 56 formed by the binder includes various shapes such as granular, cylindrical, sheet, spherical, single-hole cylindrical, multi-hole cylindrical, and tablet-like.

A combustion chamber 60 containing a gas generating agent 61 is located in a space surrounding a portion of the interior of the housing where the cup-shaped member 50 is arranged. Specifically, as described above, the cup-shaped member 50 projects into the combustion chamber 60 formed inside the housing, and faces the outer surface of the side wall portion 52 of the cup-shaped member 50 . The space provided in the portion and the space provided in the portion facing the outer surface of the top wall portion 51 are configured as a combustion chamber 60 .

A filter 90 is arranged along the inner circumference of the housing in a space radially surrounding the combustion chamber 60 containing the gas generating agent 61 . The filter 90 has a cylindrical shape and is arranged such that its central axis substantially coincides with the axial direction of the housing.

The gas generating agent 61 is a chemical that is ignited by thermal particles generated by the operation of the igniter 40 and burns to generate gas. As the gas generating agent 61, it is preferable to use a non-azide gas generating agent, and generally the gas generating agent 61 is formed as a compact containing a fuel, an oxidant and an additive.

As the fuel, for example, a triazole derivative, a tetrazole derivative, a guanidine derivative, an azodicarbonamide derivative, a hydrazine derivative, or a combination thereof is used. Specifically, nitroguanidine, guanidine nitrate, cyanoguanidine, 5-aminotetrazole and the like are preferably used.

Examples of the oxidizing agent include basic nitrates such as basic copper nitrate, perchlorates such as ammonium perchlorate and potassium perchlorate, alkali metals, alkaline earth metals, transition metals, and cations selected from ammonia. Nitrate containing is used. As nitrates, for example, sodium nitrate, potassium nitrate and the like are preferably used.

Examples of additives include binders, slag forming agents, and combustion modifiers. As the binder, organic binders such as metal salts of carboxymethyl cellulose and stearates, and inorganic binders such as synthetic hydrotalcite and acid clay can be preferably used. As the slag forming agent, silicon nitride, silica, acid clay, and the like can be suitably used, for example. Also, as the combustion modifier, for example, metal oxides, ferrosilicon, activated carbon, graphite, etc. can be suitably used.

The shape of the molded body of the gas generating agent 61 includes various shapes such as granular shapes such as granules, pellets, and cylindrical shapes, and disk shapes. In addition, in the case of a columnar shape, a perforated shaped body having through holes inside the shaped body (for example, a single-hole cylindrical shape, a porous cylindrical shape, etc.) is also used. These shapes are preferably selected appropriately according to the specifications of the airbag device in which the disk-type gas generator 1A is incorporated. It is preferable to select the optimum shape according to the specifications, such as selecting . In addition to the shape of the gas generating agent 61, it is preferable to appropriately select the size and filling amount of the compact in consideration of the linear burning velocity, pressure index, etc. of the gas generating agent 61.

For the filter 90, for example, a metal wire such as stainless steel or steel is wound and sintered, or a net material in which a metal wire is woven is pressed and compacted. As the mesh material, specifically, a knitted wire mesh, a plain-woven wire mesh, an aggregate of crimp-woven metal wires, or the like can be used.

As the filter 90, a wound perforated metal plate or the like can also be used. In this case, the perforated metal plate may be, for example, an expanded metal obtained by cutting a metal plate in a zigzag pattern and expanding the cuts to form holes to form a mesh, or a metal plate with holes and A hook metal or the like is used in which burrs formed on the periphery of the hole are flattened by crushing them. In this case, the size and shape of the holes to be formed can be changed as needed, and holes of different sizes and shapes may be included on the same metal plate. As the metal plate, for example, a steel plate (mild steel) or a stainless steel plate can be suitably used, and a non-ferrous metal plate such as aluminum, copper, titanium, nickel or alloys thereof can also be used.

When the gas generated in the combustion chamber 60 passes through the filter 90, the filter 90 functions as a cooling means for cooling the gas by removing high-temperature heat from the gas, and removes residue contained in the gas. It also functions as a removing means for removing (slag) and the like. 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 within the combustion chamber 60 passes through the filter 90 . In the filter 90, a gap 28 of a predetermined size is formed between the cylindrical portion 22 of the upper shell 20 and the cylindrical portion 12 of the lower shell 10, which constitute the peripheral wall portion of the housing. It is spaced apart from the tubular portions 12 and 22 so as to be arranged.

As shown in FIGS. 1 and 2, the cylindrical portion 22 of the upper shell 20 facing the filter 90 is provided with a plurality of gas ejection ports 24 . The plurality of gas ejection ports 24 are for leading out the gas that has passed through the filter 90 to the outside of the housing.

Also, as shown in FIG. 2, a metallic sealing tape 26 as a sealing member is adhered to the inner peripheral surface of the tubular portion 22 of the upper shell 20 so as to close the plurality of gas jetting ports 24 . attached. As the sealing tape 26 , an aluminum foil or the like coated with an adhesive member on one side can be suitably used, and the sealing tape 26 ensures airtightness of the combustion chamber 60 .

Here, as shown in FIG. 1, in the disk-shaped gas generator 1A according to the present embodiment, the plurality of gas ejection ports 24 are composed of three types of gas ejection ports (that is, a plurality of gas ejection ports) having different opening areas. a first gas outlet 24a, a plurality of second gas outlets 24b and a plurality of third gas outlets 24c). These three types of gas ejection ports are opened step by step as the pressure in the above-described accommodation space, which is the space inside the housing, increases as the gas generating agent 61 burns during operation of the disk-type gas generator 1A. Therefore, the opening pressures are different from each other.

As described above, the filter 90 and the gap 28 are positioned between the combustion chamber 60 and the plurality of gas ejection ports 24. However, since the flow resistance of the filter 90 to the gas is relatively small, The pressure in the accommodation space is substantially equal to the internal pressure of the combustion chamber 60 . Therefore, in the following description, this may be referred to as the internal pressure of the combustion chamber 60 instead of the pressure in the accommodation space.

The first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c described above are configured so that their opening areas are different from each other, so that their opening pressures are different from each other. In this way, by having a plurality of types of gas ejection ports 24 having different opening pressures, it is possible to prevent the internal pressure of the combustion chamber 60 from falling significantly during operation, especially in a low-temperature environment. Combustion characteristics can be obtained, the details of which and the more detailed configuration of the plurality of types of gas ejection ports 24 will be described later.

Referring to FIG. 2 again, a lower support member 70 is arranged in the vicinity of the end portion of the combustion chamber 60 located on the bottom plate portion 11 side. The lower support member 70 has an annular shape, and is arranged substantially on the filter 90 and the bottom plate portion 11 so as to cover the boundary portion between the filter 90 and the bottom plate portion 11 . there is Thus, the lower support member 70 is located between the bottom plate portion 11 and the gas generating agent 61 in the vicinity of the end portion of the combustion chamber 60 .

The lower support member 70 includes a contact portion 72 that stands upright so as to contact the inner peripheral surface of the axial end portion of the filter 90 located on the bottom plate portion 11 side, and a contact portion 72 that extends radially inward from the contact portion 72 . It has a bottom portion 71 extending toward it. Bottom portion 71 is formed to extend along the inner bottom surface of bottom plate portion 11 of lower shell 10 . Specifically, the bottom portion 71 has a shape that is bent along the shape of the inner bottom surface of the bottom plate portion 11 including the portion where the projecting tubular portion 13 is provided. It includes an upright tip 73 .

The lower support member 70 prevents the gas generated in the combustion chamber 60 from flowing out from the gap between the lower end of the filter 90 and the bottom plate portion 11 without passing through the inside of the filter 90 during operation. It functions as an outflow prevention means to prevent The lower support member 70 is formed, for example, by pressing a plate-like member made of metal, and is preferably made of steel plate such as ordinary steel or special steel (for example, cold-rolled steel plate, stainless steel plate, etc.). ).

Here, the distal end portion 54 of the extension portion 53 of the cup-shaped member 50 described above is arranged between the bottom plate portion 11 and the bottom portion 71 of the lower side support member 70 along the axial direction of the housing. As a result, the tip portion 54 is sandwiched and held between the bottom plate portion 11 and the bottom portion 71 along the axial direction of the housing. With this configuration, the tip portion 54 of the extension portion 53 of the cup-shaped member 50 is pressed toward the bottom plate portion 11 side by the bottom portion 71 of the lower side support member 70 . It will be fixed against

An upper support member 80 is arranged at an end portion of the combustion chamber 60 located on the top plate portion 21 side. The upper support member 80 has a substantially disk-like shape, and is placed between the filter 90 and the top plate portion 21 so as to cover the boundary portion between the filter 90 and the top plate portion 21 . ing. Thereby, the upper support member 80 is located between the top plate portion 21 and the gas generating agent 61 in the vicinity of the end portion of the combustion chamber 60 .

The upper support member 80 has a bottom portion 81 that abuts on the top plate portion 21 and a contact portion 82 that stands upright from the peripheral edge of the bottom portion 81 . The contact portion 82 contacts the inner peripheral surface of the axial end portion of the filter 90 located on the top plate portion 21 side.

When the upper support member 80 is operated, the gas generated in the combustion chamber 60 flows out from the gap between the upper end of the filter 90 and the top plate portion 21 without passing through the inside of the filter 90. It functions as an outflow prevention means for preventing this. Like the lower support member 70, the upper support member 80 is formed, for example, by pressing a plate-like member made of metal, and is preferably made of a steel plate such as ordinary steel or special steel (for example, , cold-rolled steel plate, stainless steel plate, etc.).

An annular cushion member 85 is arranged inside the upper support member 80 so as to come into contact with the gas generating agent 61 contained in the combustion chamber 60 . As a result, the cushion material 85 is positioned between the top plate portion 21 and the gas generating agent 61 in the portion of the combustion chamber 60 on the top plate portion 21 side, so that the gas generating agent 61 is directed toward the bottom plate portion 11 side. is pressing.

The cushion material 85 is provided for the purpose of preventing the gas generating agent 61, which is a molded body, from being pulverized by vibration or the like. It is composed of a member made of rubber such as silicone, foamed polypropylene, foamed polyethylene, etc.), chloroprene, and EPDM.

Next, referring to FIG. 2, the operation of the disk-shaped gas generator 1A according to the present embodiment described above will be described.

When the vehicle equipped with the disk-type gas generator 1A according to the present embodiment collides, the collision is detected by collision detection means separately provided in the vehicle, and based on this, a control unit separately provided in the vehicle is detected. The igniter 40 is actuated by energization from the . The transfer charge 56 contained in the transfer charge chamber 55 is ignited and burned by the flame generated by the operation of the igniter 40 to generate a large amount of thermal particles. The combustion of this transfer charge 56 causes the cup-shaped member 50 to burst or melt, and the above-mentioned hot particles flow into the combustion chamber 60 .

The hot particles that have flowed in ignite and burn the gas generating agent 61 contained in the combustion chamber 60 to generate a large amount of gas. The gas generated in the combustion chamber 60 passes through the inside of the filter 90. At that time, the filter 90 removes heat and cools the gas. flow into.

As the pressure in the space inside the housing rises, the sealing tape 26 closing the gas ejection port 24 provided in the upper shell 20 is torn, and the gas flows out of the housing through the gas ejection port 24. It is ejected. At that time, the plurality of gas ejection ports 24 are opened step by step, and the ejected gas is introduced into the airbag provided adjacent to the disk-shaped gas generator 1A, Inflate and deploy the airbag.

3 is a cross-sectional view of the upper shell taken along line III-III shown in FIGS. 1 and 2, and FIG. 4 is an enlarged view of the first to third gas ejection ports shown in FIGS. 1 and 3. is. Next, referring to FIGS. 3 and 4 as well as FIGS. 1 and 2 described above, the configuration of the upper shell 20 and the first to third portions provided in the cylindrical portion 22 of the upper shell 20 will be described in more detail. A more detailed configuration of the gas ejection ports 24a to 24c will be described.

As shown in FIG. 3, the flange portion 23 of the upper shell 20 has a shape in which the distance from the axis O of the cylindrical portion 22 of the upper shell 20 to the outer edge of the flange portion 23 is non-uniform. there is More specifically, in the disk-shaped gas generator 1A according to the present embodiment, the above-described through holes 25 are provided in the flange portion 23 at four locations evenly along the circumferential direction. The distance at the portion provided with is greater than the distance at the portion of the flange portion 23 where the through hole 25 is not provided.

As a result, of the outer edge of the flange portion 23, the maximum outer shape position A, which is the farthest position from the axis O of the tubular portion 22, is added to the positions corresponding to the through holes 25 provided in the flange portion 23. , and are evenly positioned at intervals of 90[°] along the circumferential direction of the cylindrical portion 22 of the upper shell 20 .

On the other hand, as shown in FIGS. 1 and 3, in the disk-shaped gas generator 1A according to the present embodiment, the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c are They are arranged in a line along the circumferential direction of the cylindrical portion 22 of the upper shell 20 according to a predetermined rule. More specifically, the plurality of gas ejection ports 24 are 24 in total, and are evenly arranged at intervals of 15[°] along the circumferential direction of the cylindrical portion 22 of the upper shell 20 .

The number of the first gas ejection ports 24 a is four, and they are arranged along the circumferential direction of the cylindrical portion 22 of the upper shell 20 at intervals of 90[°]. The number of the second gas ejection ports 24b is eight, and they are arranged along the circumferential direction of the cylindrical portion 22 of the upper shell 20 at intervals of 45[°]. The number of the third gas ejection ports 24c is twelve, and the number of the third gas ejection ports 24c is 15 [°], 30 [°], 45 [°], 15 [°] along the circumferential direction of the tubular portion 22 of the upper shell 20. , 30[°], 45[°], .

Here, the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c are arranged along the circumferential direction of the cylindrical portion 22 of the upper shell 20 to form the first gas ejection port 24a, the second gas ejection port 24b, and the second gas ejection port 24c. The gas ejection port 24b, the third gas ejection port 24c, the third gas ejection port 24c, the second gas ejection port 24b, and the third gas ejection port 24c are arranged in this order so that four sets are repeated. . As a result, the plurality of gas ejection ports 24 are arranged so as not to overlap each other in the circumferential direction of the cylindrical portion 22 of the upper shell 20 .

As shown in FIGS. 1 and 4A, the first gas ejection port 24a has an elongated hole shape with different opening widths in directions perpendicular to each other. The opening width L1 along the axial direction of the tubular portion 22 (hereinafter, the opening width L1 along the axial direction of the tubular portion 22 is also referred to as the length L1) is the length L1 along the circumferential direction of the tubular portion 22. It has a vertically long hole shape larger than the opening width W1 (hereinafter, the opening width W1 along the circumferential direction of the cylindrical portion 22 is also simply referred to as the width W1). Strictly speaking, the first gas ejection port 24 a is configured by a track hole having a pair of opening edges extending in parallel along the axial direction of the cylindrical portion 22 .

As shown in FIGS. 1 and 4B, the second gas ejection port 24b has an elongated hole shape with different opening widths in directions perpendicular to each other. The opening width L2 along the axial direction of the tubular portion 22 (hereinafter, the opening width L2 along the axial direction of the tubular portion 22 is also referred to as the length L2) is the length L2 along the circumferential direction of the tubular portion 22. It has a vertically long hole shape larger than the opening width W2 (hereinafter, the opening width W2 along the circumferential direction of the cylindrical portion 22 is also simply referred to as the width W2). Strictly speaking, the second gas ejection port 24b is composed of a track hole having a pair of opening edges extending in parallel along the axial direction of the cylindrical portion 22. As shown in FIG.

As shown in FIGS. 1 and 4C, the third gas ejection port 24c has an elongated hole shape with different opening widths in mutually orthogonal directions. The opening width L3 along the axial direction of the tubular portion 22 (hereinafter, the opening width L3 along the axial direction of the tubular portion 22 is also referred to as the length L3) is the length L3 along the circumferential direction of the tubular portion 22. It has a vertically long hole shape larger than the opening width W3 (hereinafter, the opening width W3 along the circumferential direction of the cylindrical portion 22 is also simply referred to as the width W3). Strictly speaking, the third gas ejection port 24c is configured by a track hole having a pair of opening edge portions extending in parallel along the axial direction of the tubular portion 22 .

That is, the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c all have a vertically elongated hole shape, whereby all the gas ejection ports 24 have a vertically elongated hole shape. It means that

4A to 4C, let S1 be the opening area of each first gas ejection port 24a, S2 be the opening area of each second gas ejection port 24b, and Assuming that the opening area of each of the third gas ejection ports 24c is S3, S1 to S3 satisfy the condition of S1>S2>S3. That is, the opening area S2 of the second gas ejection port 24b is smaller than the opening area S1 of the first gas ejection port 24a, and the opening area S3 of the third gas ejection port 24c is smaller than the opening area S2 of the second gas ejection port 24b. less than

Here, as shown in FIG. 3, in the disk-shaped gas generator 1A according to the present embodiment, a perpendicular line PL is drawn from the above-described maximum outer shape position A of the flange portion 23 to the axis O of the tubular portion 22. In the case (in FIG. 3, the case where the perpendicular PL is drawn from one of the four maximum outer shape positions A is representatively illustrated), the gas jet arranged at the position closest to the perpendicular PL The outlet 24 is the first gas outlet 24a, the second gas outlet 24b, and the third gas outlet 24c other than the first gas outlet 24a, which has the largest opening area.

More specifically, when viewed along the axis O of the tubular portion 22, the tubular portion 22 is provided with the third gas ejection port 24c so as to overlap the perpendicular line PL. As a result, the gas ejection port 24 located closest to the perpendicular PL is the third gas ejection port having the smallest opening area among the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c. A gas ejection port 24c is provided.

By configuring in this way, even when the thickness of the housing, which is a pressure-resistant container (that is, the thickness of the upper shell 20) is reduced in order to reduce the size and weight, it is possible to ensure high pressure-resistant performance. However, this point will be discussed later.

2, the sealing tape 26 is attached to the inner peripheral surface of the upper shell 20 as described above. each is closed. In this case, F is the shear strength (tensile strength) of the seal tape 26, t is the thickness of the seal tape 26 at the portion that closes the gas ejection port 24, and C is the circumference of the gas ejection port (the circumference shown in FIG. 4). C1 to C3 correspond to the perimeter C), and the opening area of the gas ejection port 24 is S (the opening areas S1 to S3 described above correspond to the opening area S). The outlet opening pressure is expressed as F×t×C/S.

Therefore, by appropriately adjusting the circumferential lengths C1 to C3 and the opening areas S1 to S3, in the present embodiment, the opening pressure of the first gas ejection port 24a is the lowest, and the opening pressure of the second gas ejection port 24b is the lowest. is the second lowest, and the opening pressure of the third gas ejection port 24c is set to be the highest.

When setting the opening pressure, it is possible to increase the opening pressure by setting the circumferential length C longer even when the opening area S is the same, as can be understood from the above expression of the opening pressure. In other words, as in the present embodiment, each of the plurality of gas ejection ports 24 is configured to have a vertically long hole shape, so that adjacent gas ejection ports 24 are arranged in order to suppress deterioration of the pressure resistance performance of the housing. Various opening pressures can be set while sufficiently securing the space between the outlets 24, and a part of the plurality of gas ejection ports is simply enlarged to have a similar shape while maintaining a perfect circular shape, thereby forming a plurality of gas outlets. Compared to the case where the opening pressure of a plurality of gas ejection ports is set stepwise while increasing the total opening area of the ejection ports, the degree of freedom in design is greatly increased, resulting in the miniaturization of the disk-type gas generator 1A. becomes possible.

Here, as the filter 90, when using a material obtained by winding and sintering a metal wire such as stainless steel or iron or the like, or a material obtained by pressing a mesh material woven with a metal wire and compacting it, During operation, the pressure of the gas ejected from the gas ejection port 24 deforms the portion of the filter 90 facing the gas ejection port 24, and the deformed portion is pushed outward. A phenomenon may occur in which the liquid oozes out from the ejection port 24 toward the outside.

This phenomenon is more likely to occur when the shape of the gas ejection port 24 is circular, and is less likely to occur when it is non-circular. This is because when the shape of the gas ejection port 24 is non-perfect circular, the flow resistance to the gas increases at the corners and corners of the gas ejection port 24 of the shape, and the opening area of the gas ejection port 24 increases. It is presumed that this is because the flow rate of the gas that actually flows is kept low as a whole, and the force that pushes the filter 90 outward is reduced.

Based on this point of view, the shape of the gas ejection port 24 is preferably a non-perfect circular shape as typified by the above-described vertically elongated hole shape. A non-perfect circular shape is preferable as the shape is increased. In addition, the non-perfect circular shape referred to here includes various shapes, and in addition to the above-described vertically long hole shape, there are a horizontally long hole shape, an oblique hole shape, etc., and furthermore, a cross shape and a V shape. , T-shaped, asterisk-shaped, and shapes obtained by rotating these around the center.

When this is quantified and shown, at least one of the plurality of first gas ejection ports 24a, the plurality of second gas ejection ports 24b, and the plurality of third gas ejection ports 24c is one. S [mm ² ] is the opening area of each gas ejection port, and C [mm] is the peripheral length of the gas ejection port. It is preferable that the gas ejection port has a shape that satisfies the condition of ^0.5 , and more preferably that the condition of S/C≦0.22×S ^0.5 is satisfied.

FIG. 5 is a diagram schematically showing how the gas ejection port is opened step by step during operation of the gas generator according to the present embodiment. Next, with reference to FIG. 5, the reason why the disk-shaped gas generator 1A according to the present embodiment can prevent a large decrease in internal pressure increase during operation especially in a low-temperature environment will be described. 5(A), 5(B), and 5(C) schematically show the state after a predetermined time has elapsed from the start of operation. The elapsed time is longer in the order of FIG. 5(B) and FIG. 5(C).

When the disk-shaped gas generator 1A in this embodiment operates, the gas generating agent 61 starts burning, and the internal pressure of the combustion chamber 60 starts to rise accordingly. In the disk-shaped gas generator 1A according to the present embodiment, the plurality of gas ejection ports 24 are opened step by step in the process of increasing the internal pressure of the combustion chamber 60 .

In the first stage after the start of operation, the internal pressure of the combustion chamber 60 reaches a pressure capable of opening all of the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c. Therefore, the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c are not opened, and the internal pressure continues to rise.

In the second stage after the start of operation, the internal pressure of the combustion chamber 60 is the four gas outlets having the lowest opening pressure among the first gas outlet 24a, the second gas outlet 24b, and the third gas outlet 24c. The internal pressure P1 that can open the first gas ejection port 24a is reached, and along with this, as shown in FIG. , the gas is ejected through the four open first gas ejection ports 24a. As a result, the gas output can be obtained in a relatively short time after the start of operation, and the inflation and deployment of the airbag can be started early.

Here, in the second stage after the start of the operation, the second gas ejection port 24b and the third gas ejection port 24c are not yet opened, so the internal pressure of the combustion chamber 60 reaches an appropriately high pressure state. As a result, the internal pressure of the combustion chamber 60 does not drop extremely. Therefore, stable combustion of the gas generating agent 61 is continued, and inflation and deployment of the airbag can be continued.

In the third stage after the start of operation, the internal pressure of the combustion chamber 60 is the second lowest after the first gas outlet 24a among the first gas outlet 24a, the second gas outlet 24b, and the third gas outlet 24c. The internal pressure P2 that can open the eight second gas ejection ports 24b having the opening pressure is reached, and along with this, the eight second gas ejection ports 24b are covered as shown in FIG. 5(B). The partial seal tape 26 is cleaved, and the gas is released through a total of 12 open first gas outlets 24a and second gas outlets 24b, including the already opened four first gas outlets 24a. is ejected.

Here, in the third stage after the start of operation, the third gas ejection port 24c is not yet opened, so the internal pressure of the combustion chamber 60 is maintained at an appropriately high pressure. The internal pressure of the combustion chamber 60 is prevented from dropping extremely. Therefore, stable combustion of the gas generating agent 61 is continued, and inflation and deployment of the airbag can be continued.

In the fourth stage after the start of operation, the internal pressure of the combustion chamber 60 is 12 that have the highest opening pressure among the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c. The internal pressure reaches P3, which is capable of opening the three gas ejection ports 24c, and along with this, as shown in FIG. , all twenty-four open first gas outlets 24a, second gas outlets 24b, including a total of twelve already opened first gas outlets 24a and second gas outlets 24b Gas is ejected through the third gas ejection port 24c.

Here, at this time, the internal pressure of the combustion chamber 60 has already reached a sufficiently high pressure state, so the gas generating agent 61 will continue to burn stably, and all of the gas generating agent 61 will burn out. A high gas output can be stably obtained up to , and the sustained deployment of the airbag can be further continued.

In the fifth stage after the start of operation, the gas generating agent 61 is completely burnt out and the output of gas is stopped, whereby the operation of the disk-type gas generator 1A is terminated and the deployment of the airbag is also terminated.

As described above, in the disk-type gas generator 1A according to the present embodiment, when the disk-type gas generator 1A is in operation, the pressure in the above-described accommodation space, which is the space inside the housing, is increased as the gas generating agent 61 is burned. Since the plurality of gas ejection ports 24 are designed to be opened step by step as the housing rises, all the gas ejection ports are opened simultaneously as the pressure in the space inside the housing increases. Compared to the disc-type gas generator thus constructed, it is possible to prevent a large drop in internal pressure rise, especially in a low-temperature environment. Therefore, it becomes possible to continuously burn the gas generating agent 61 in any temperature environment from a high temperature environment to a low temperature environment, and as a result, it is possible to reduce the performance difference in gas output caused by the environmental temperature. becomes possible.

In order to reliably obtain the effect of reducing the performance difference in gas output caused by the environmental temperature by setting the plurality of gas ejection ports 24 to be opened in three stages, Let SA1 be the sum of the opening areas of the first gas ejection ports 24a, SA2 be the sum of the opening areas of the plurality of second gas ejection ports 24b, and SA3 be the sum of the opening areas of the plurality of third gas ejection ports 24c. (in this embodiment, SA1=4.times.S1, SA2=8.times.S2, SA3=12.times.S3), these SA1 to SA3 preferably satisfy the condition SA1<SA2+SA3. That is, the sum SA1 of the opening areas of the plurality of first gas ejection ports 24a is the sum SA2 of the opening areas of the plurality of second gas ejection ports 24b and the sum SA3 of the opening areas of the plurality of third gas ejection ports 24c. is preferably smaller than the sum of This is because when the sum (SA1) of the opening areas of the plurality of first gas ejection ports 24a in the total sum of the opening areas of the plurality of gas ejection ports 24 (that is, SA1+SA2+SA3) is large, the internal pressure of the combustion chamber 60 This is because it becomes difficult to maintain the high pressure state.

FIG. 6(A) is a diagram schematically showing the degree of deformation of the main part of the housing during operation of the disk-shaped gas generator according to the comparative example, and FIG. FIG. 4 is a diagram schematically showing the degree of deformation of the main part of the housing during operation of the disk-type gas generator. Next, referring to FIG. 6 and FIG. 2 described above, main parts of the housings of the disk-shaped gas generator 1X according to the comparative example and the disk-shaped gas generator 1A according to the present embodiment are operated. By explaining the difference in the degree of deformation, in the disk-type gas generator 1A according to the present embodiment, even if the thickness of the housing, which is a pressure-resistant container, is reduced in order to reduce the size and weight, the pressure resistance performance can be increased. The reason why it is possible to secure is explained in detail. The cross section shown in FIG. 6(B) is a cross section of the housing of the disk-shaped gas generator 1A according to the present embodiment taken along line VIB-VIB shown in FIG. is a cross section corresponding to the cross section shown in FIG. 6(B) of the housing of the disk-shaped gas generator 1X according to the comparative example.

In general, when the disk-type gas generator is operated, the pressure in the space inside the housing rises and the housing deforms so as to swell outward. stress concentration occurs at At that time, if the degree of deformation of the housing is relatively large and a stress greater than the withstand voltage of the housing is generated in the corresponding portion, the housing will break starting from the corresponding portion. On the other hand, if the degree of deformation of the housing is relatively small and no stress exceeding the withstand voltage of the housing is generated in the relevant portion, the housing will not break and the operation of the disk-type gas generator will be completed normally. become.

Here, referring to FIG. 2, the portion where stress concentration is likely to occur is the portion of the tubular portion 22 of the upper shell 20 that is connected to the flange portion 23 (the portion indicated by region R in FIG. 2). is mentioned. The cylindrical portion 22 itself is a portion that is relatively easily deformed as the pressure in the space inside the housing increases. As a result, the deformation of the portion is constrained by the flange portion 23, and as a result, a large stress is generated in the region R described above.

Furthermore, in the region R, in the vicinity of the maximum outer shape position A (see FIG. 3) of the flange portion 23, the radially outward protrusion amount of the flange portion 23 is configured to be particularly large. The binding force by the portion 23 acts strongly, and as a result, the stress is generated more intensively than in the other portions of the region R. Therefore, if a stress exceeding the withstand voltage of the housing does not occur in the region R of the flange portion 23 near the maximum outer shape position A, the housing will basically not break.

On the other hand, when a plurality of gas ejection ports 24 including those having opening areas different from each other are provided in the cylindrical portion 22 of the upper shell 20, as in the disk-shaped gas generator 1A of the present embodiment. , the deformation of the cylindrical portion 22 is relatively large in the vicinity of the portion where the gas ejection port with the larger opening area is provided, and the cylindrical portion 22 is deformed in the vicinity of the portion where the gas ejection port with the smaller opening area is provided. Deformation of the portion 22 is relatively small. This is because the mechanical strength of the cylindrical portion 22 is relatively low in the vicinity of the portion where the gas ejection port with the larger opening area is provided, and the vicinity of the portion where the gas ejection port with the smaller opening area is provided. This is because the mechanical strength of the cylindrical portion 22 is relatively high.

Referring to FIG. 6(A), disk-shaped gas generator 1X according to the comparative example has a tubular shape from maximum outer shape position A of flange portion 23 when compared with disk-shaped gas generator 1A according to the present embodiment. When a perpendicular line is drawn to the axis of the portion 22, the gas ejection ports 24 arranged closest to the perpendicular line are the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c. The difference is that the first gas ejection port 24a has the largest opening area among them.

In the disk-shaped gas generator 1X according to the comparative example configured as described above, the first gas jet having the largest opening area is located in the vicinity of the portion of the cylindrical portion 22 corresponding to the maximum outer shape position A of the flange portion 23. Due to the provision of the outlet 24a, a portion of the cylindrical portion 22 with relatively low mechanical strength and a portion of the cylindrical portion 22 where the restraining force of the flange portion 23 acts most strongly are They are arranged overlapping in the circumferential direction of the housing.

Therefore, as shown in FIG. 6(A), during operation of the disk-shaped gas generator 1X according to the comparative example, in the portion corresponding to the maximum outer shape position A of the flange portion 23 in the above-described region R, the A relatively large deformation occurs in the cylindrical portion 22 corresponding to the portion (that is, a large amount of deformation occurs in the cylindrical portion 22 as indicated by reference symbol D0 in the drawing), while the flange portion 23 restrains the A strong force acts, and as a result, a concentrated stress is generated in that portion of the region R.

Therefore, in the disk-shaped gas generator 1X according to the comparative example, it is necessary to increase the thickness of the upper shell 20 relatively in order to prevent the upper shell 20 from breaking at that portion. , which hinders miniaturization and weight reduction.

On the other hand, as shown in FIG. 6(B), in the disk-shaped gas generator 1A according to the present embodiment, a Since the third gas ejection port 24c having the smallest opening area is provided, the portion of the tubular portion 22 having relatively high mechanical strength and the flange portion 23 of the tubular portion 22 restrain the gas. The portion where the force acts most strongly is arranged to overlap in the circumferential direction of the housing.

Therefore, as shown in FIG. 6(B), during operation of the disk-shaped gas generator 1A in the present embodiment, in the portion corresponding to the maximum outer shape position A of the flange portion 23 in the region R described above, While the restraining force of the flange portion 23 is strong, the cylindrical portion 22 corresponding to this portion undergoes relatively small deformation (i.e., a small amount of deformation as indicated by D1 in the drawing (i.e., D1<D0) occurs in the cylindrical portion 22), so that the stress concentration occurring in this portion of the region R can be greatly reduced as a result.

Therefore, in disk-shaped gas generator 1A according to the present embodiment, it is possible to make the thickness of upper shell 20 relatively thin as compared with disk-shaped gas generator 1X according to the comparative example described above. As a result, reduction in size and weight can be achieved.

As described above, by using the disk-type gas generator 1A according to the present embodiment, it is possible to reduce the size and weight while ensuring the pressure resistance performance, and to reduce the performance difference in gas output caused by the environmental temperature. It becomes possible to realize a gas generator.

Here, referring to FIG. 3, disk-shaped gas generators 1A according to the present embodiment are configured to have the same shape and the same opening area so as to have the same opening pressure. In the case of focusing on the gas ejection openings that are formed and grasping them as a group of gas ejection openings according to their formation positions, the plurality of gas ejection openings described above can be obtained only by the following multiple sets of gas ejection opening groups. 24 can be seen to be configured. As described above, the gas ejection port group is determined so that as many gas ejection ports as possible form one set of gas ejection port groups.

First gas ejection port group X: a total of four gas ejection ports 24a arranged at intervals of 90[°]
Second gas ejection port group Y: A total of eight gas ejection ports 24b arranged at intervals of 45[°]
Third gas ejection port group Z1: A total of eight gas ejection ports 24c arranged at intervals of 45[°]
Third gas ejection port group Z2: A total of four gas ejection ports 24c arranged at intervals of 90[°]

That is, in the disk-shaped gas generator 1A of the present embodiment, the plurality of gas ejection ports 24 are rotationally symmetrical with an angle of 120[°] or less about the axis O of the cylindrical portion 22 of the upper shell 20. A total of four gas ejection port groups X, Y, Z1, each of which is composed of a plurality of gas ejection ports having the same opening pressure and are evenly arranged along the circumferential direction of the cylindrical portion 22 so as to have the same opening pressure. , Z2 only.

With this configuration, if the fixing force of an external member (for example, a retainer of an airbag device, etc.) for fixing the disk-shaped gas generator 1A is insufficient only at some positions in the circumferential direction of the housing (for example, due to aging) Even if the fixing force is lowered due to deterioration, etc., it is possible to prevent the balance of the thrust applied to the disk-shaped gas generator 1A from being greatly disturbed.

More specifically, in the second stage after the start of the operation described above, the four first gas ejection ports 24a evenly arranged along the circumferential direction of the cylindrical portion 22 of the upper shell 20 are opened. In this state, the gas is jetted out at four locations equidistantly along the circumferential direction of the cylindrical portion 22, and if by any chance the fixing force of the fixing member fixing the disk-shaped gas generator 1A is insufficient only at some positions in the circumferential direction of the housing, the balance of thrust applied to the disk-shaped gas generator 1A is relatively unlikely to be lost.

Further, in the third stage after the start of the operation described above, a total of 12 first gas ejection ports 24a and 12 second gas ejection ports 24a and 24a are arranged approximately evenly along the circumferential direction of the tubular portion 22 of the upper shell 20. Since the ejection port 24b is in an open state, the gas is ejected at 12 locations that are approximately equally spaced along the circumferential direction of the cylindrical portion 22. Even if the fixing force of the fixing member for fixing is insufficient only at some positions in the circumferential direction of the housing, the balance of the thrust applied to the disk-shaped gas generator 1A is considerably less likely to be lost.

Therefore, by adopting the above configuration, it is possible to provide a disk-type gas generator with enhanced safety, particularly in the initial stages after the start of operation.

In addition, in the above-described second and third stages after the start of operation, the airbag has not yet fully deployed, so that the distance between the opened gas ejection port 24 and the airbag is large. Although they are in a very close state, even at that time, at four positions equally spaced along the circumferential direction of the cylindrical portion 22 of the upper shell 20 and twelve positions substantially equally spaced. Since each gas is dispersed and ejected, it is possible to avoid the high-temperature and high-pressure gas from being concentrated and ejected to a localized portion of the airbag. Therefore, by adopting the above configuration, the possibility of damaging the airbag can be reduced.

Of the plurality of gas ejection ports 24, all gas ejection ports other than the gas ejection ports 24c included in the third gas ejection port groups Z1 and Z2 (that is, the first gas ejection ports 24a and the second gas ejection ports 24c) All of the two gas ejection ports 24 b ) are arranged substantially evenly along the circumferential direction of the cylindrical portion 22 of the upper shell 20 . In addition, in the disk-type gas generator 1A according to the present embodiment, all of the plurality of gas ejection ports 24 (that is, the third gas ejection ports 24c are provided for the first gas ejection ports 24a and the second gas ejection ports 24b). are evenly arranged along the circumferential direction of the tubular portion 22 of the upper shell 20, the tubular portion 22 of the upper shell 20 is evenly arranged in the above-described fourth stage after the start of operation. The gas is dispersed and jetted out at 24 equally spaced positions along the circumferential direction.

Further, by adopting the above structure, the opening area of each of the plurality of gas ejection ports 24 provided in the housing can be kept small, and the number of gas ejection ports 24 can be increased. It is possible to lower the pressure considerably within a range in which the gas generating agent 61 can stably and sustainably burn. Therefore, in this sense as well, it is possible to reduce the thickness of the housing while ensuring the pressure resistance of the housing.

The disk-shaped gas generator 1A according to the present embodiment is of a type that inflates and deploys a standard-sized airbag, and the outer diameter of the cylindrical portion 22 of the upper shell 20 is, for example, 60 mm. .4 [mm], and the thickness (plate thickness) of the tubular portion 22 is designed to be, for example, 1.1 [mm].

In this case, the length L1 and the width W1 of the first gas ejection port 24a are set to, for example, 4.0 [mm] and 1.9 [mm], respectively, and the length L2 and the width W1 of the second gas ejection port 24b are set to Width W2 is set to, for example, 3.3 [mm] and 1.4 [mm], respectively, and length L3 and width W3 of third gas ejection port 24c are set, for example, to 2.5 [mm] and 1.3 [mm], respectively. It is set to [mm].

Here, the formation of the plurality of gas ejection ports 24 is generally performed by punching using a press machine. Since the pitch becomes small, it is practically impossible to do this in a single punching process due to limitations of the press machine.

However, from the viewpoint of reducing manufacturing costs, it is preferable to form all of the plurality of gas ejection ports 24 by performing the punching process as few times as possible. In this case, in the step of forming the plurality of gas ejection ports 24, a total of 12 gas ejection ports arranged at intervals of 30[°] along the circumferential direction of the tubular portion 22 are punched once. It is preferable to form a total of 12 gas ejection ports arranged at intervals of 30[°] along the circumferential direction of the cylindrical portion 22 by a single punching process. By doing so, all of the plurality of gas ejection ports 24 can be formed by two punching processes, and the manufacturing cost can be reduced.

As in the present embodiment described above, by making the shape of the gas ejection port 24 an elongated hole, the difference in environmental temperature (i.e., whether it is under a low temperature environment, a It is possible to make the actual opening area of the gas ejection port 24 in the open state different depending on the environment), and it is possible to promote the combustion of the gas generating agent 61 especially in a low temperature environment. become. Therefore, it is possible to remarkably reduce the performance difference in the gas output caused by the environmental temperature, and it is possible to obtain a disk-type gas generator with higher performance than the conventional one. This point will be described in detail below.

FIG. 7 is a diagram schematically showing the state in the vicinity of the gas ejection port during operation of the gas generator according to the present embodiment. In addition, FIG. 7(A) shows a case where the gas generator is operated in a normal temperature environment and a high temperature environment, and FIG. 7(B) shows a case where the gas generator is operated in a low temperature environment. indicates the case.

As shown in FIG. 7(A), when the disk-type gas generator 1A of the present embodiment is operated under a normal temperature environment and a high temperature environment, as the internal pressure of the combustion chamber 60 rises, the gas ejection port 24 When the seal tape 26 at the portion that closes the is split, the seal tape 26 is completely broken along the opening edge of the gas ejection port 24 having a long hole shape, and the opening edge of the gas ejection port 24 is broken. The sealing tape 26 does not adhere. Therefore, the opening area of the gas ejection port 24 becomes the same as the actual opening area when the gas ejection port 24 is opened by tearing the seal tape 26 .

On the other hand, as shown in FIG. 7B, when the disk-type gas generator 1A of the present embodiment is operated in a low-temperature environment, the gas ejection port 24 is closed as the internal pressure of the combustion chamber 60 rises. When the seal tape 26 at the part where the gas is torn is torn, the seal tape 26 is torn along the opening edge of the gas ejection port 24 having a long hole shape, but is completely torn along the entire circumference of the opening edge. However, one of the pair of opening edge portions extending in parallel along the cylindrical portion 22 is not broken, and the seal tape 26 after the break is attached to the opening edge portion of the gas ejection port 24. . Therefore, the actual opening area of the gas ejection port 24 in the state where the gas ejection port 24 is opened by tearing the seal tape 26 is smaller than the opening area of the gas ejection port 24 by an amount corresponding to the cross-sectional area of the seal tape 26. will be.

Therefore, in a normal temperature environment and a high temperature environment, a relatively large sum of the actual opening areas of the gas ejection ports 24 is ensured when the disk-type gas generator 1A is in operation. The total area of the actual openings of the gas ejection ports 24 during operation of the type gas generator 1A is relatively reduced. As a result, in a low temperature environment, the amount of gas discharged through the gas ejection port 24 is restricted by opening the gas ejection port 24 compared to a normal temperature environment and a high temperature environment. , the increase in the internal pressure of the combustion chamber 60 is accelerated accordingly. Therefore, it becomes possible to promote the combustion of the gas generating agent 61, especially in a low temperature environment, and to significantly reduce the difference in gas output performance caused by the environmental temperature. As a result, a disk-type gas generator with higher performance can be obtained.

Here, by adopting the configuration as in this embodiment, whether or not part of the cleaved seal tape 26 adheres to the opening edge of the gas ejection port 24 depends on the ambient temperature. The reason is that the distance from the center of the gas ejection port 24 to the edge of the opening becomes non-uniform because the gas ejection port 24 has a non-circular long hole shape, so that The instantaneous energy required to break the seal tape 26 at once increases, and the internal pressure of the combustion chamber 60 rises quickly under normal temperature and high temperature environments, so the instantaneous energy can be obtained. On the other hand, it is presumed that this instantaneous energy cannot be obtained because the internal pressure of the combustion chamber 60 rises slowly in a low-temperature environment.

In the present embodiment, as a typical example of the elongated hole shape, the case where the gas ejection port 24 is constituted by a track hole has been described, but the gas ejection port 24 has this opening shape. For example, it may be elliptical or rectangular. Here, in order to obtain the above effect more reliably, the long-hole-shaped gas ejection port 24 should have a pair of opening edge portions extending in parallel along the cylindrical portion 22 . Preferably, it is more preferably configured by the track-shaped or rectangular-shaped holes described above.

Further, in the present embodiment, the case where all of the plurality of gas ejection ports 24 are configured to have a vertically long hole shape has been described as an example. A considerable effect can be obtained even if only a portion of the gas outlets 24 are configured to have a vertically elongated hole shape, and all or a portion of the plurality of gas ejection ports 24 are configured to have a horizontally elongated hole shape. Even when configured, it is possible to obtain the same effects as those described above. Here, the laterally elongated hole shape is an elongated hole shape in which the opening width along the circumferential direction of the tubular portion 22 of the upper shell 20 is larger than the opening width along the axial direction of the tubular portion 22 . be.

Further, in the present embodiment, a case where a plurality of gas ejection ports 24 are arranged in a row along the circumferential direction of cylindrical portion 22 of upper shell 20 has been described as an example. These may be arranged in a zigzag pattern or over a plurality of rows, or may be arranged in another layout.

The above-described low temperature environment, normal temperature environment, and high temperature environment are, for example, an environment with an environmental temperature of around -40 [°C], an environment of around 20 [°C], and an environment of around 85 [°C]. means

(Embodiment 2)
8 is a front view of a disk-type gas generator according to Embodiment 2 of the present invention, and FIG. 9 is a cross-sectional view of the upper shell taken along line IX-IX shown in FIG. First, referring to FIGS. 8 and 9, the configuration of the disk-shaped gas generator 1B in this embodiment will be described.

The disk-shaped gas generator 1B in this embodiment is of a type that inflates and deploys a standard-sized airbag, like the disk-shaped gas generator 1A in the first embodiment described above. 8 and 9, the tubular portion 22 of the upper shell 20 has a first gas ejection port 24a having the same shape and size as those of the disk-shaped gas generator 1A in the first embodiment described above, and a first gas ejection port 24a. A second gas ejection port 24b and a third gas ejection port 24c (see FIGS. 1 and 4, etc.) are provided.

In the present embodiment, the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c are arranged along the circumferential direction of the cylindrical portion 22 of the upper shell 20 according to a predetermined rule (however, They are arranged in a row according to a rule different from the rule shown in the first embodiment described above). More specifically, the plurality of gas ejection ports 24 are 24 in total and are arranged at predetermined angles along the circumferential direction of the cylindrical portion 22 of the upper shell 20 .

The number of the first gas ejection ports 24 a is four, and they are arranged along the circumferential direction of the cylindrical portion 22 of the upper shell 20 at intervals of 90[°]. The number of the second gas ejection ports 24b is eight, and the number of the second gas ejection ports 24b is 39 [°], 51 [°], 39 [°], 51 [°] along the circumferential direction of the tubular portion 22 of the upper shell 20. , , and so on. The number of the third gas ejection ports 24c is 12, and the number of the third gas ejection ports 24c is 21 [°], 30 [°], 39 [°], 21 [°] along the circumferential direction of the cylindrical portion 22 of the upper shell 20. , 30[°], 39[°], .

Here, the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c are arranged along the circumferential direction of the cylindrical portion 22 of the upper shell 20 to form the first gas ejection port 24a, the second gas ejection port 24b, and the second gas ejection port 24c. The gas ejection port 24b, the third gas ejection port 24c, the third gas ejection port 24c, the second gas ejection port 24b, and the third gas ejection port 24c are arranged in this order so that four sets are repeated. . As a result, the plurality of gas ejection ports 24 are arranged so as not to overlap each other in the circumferential direction of the cylindrical portion 22 of the upper shell 20 .

Note that the above-described first gas jet port 24a, second gas jet port 24b, third gas jet port 24c, third gas jet port 24c, second gas jet port 24b, third gas jet port 24c, first gas jet port The arrangement intervals between the gas ejection ports 24 arranged in the order of the outlets 24a, . . . °], 9 [°], .

Here, referring to FIG. 9, disk-shaped gas generators 1B according to the present embodiment are configured to have the same shape and the same opening area so as to have the same opening pressure. In the case of focusing on the gas ejection openings that are formed and grasping them as a group of gas ejection openings according to their formation positions, the plurality of gas ejection openings described above can be obtained only by the following multiple sets of gas ejection opening groups. 24 can be seen to be configured. As described above, the gas ejection port group is determined so that as many gas ejection ports as possible form one set of gas ejection port groups.

First gas ejection port group X: a total of four gas ejection ports 24a arranged at intervals of 90[°]
Second gas ejection port group Y1: a total of four gas ejection ports 24b arranged at intervals of 90[°]
Second gas ejection port group Y2: A total of four gas ejection ports 24b arranged at intervals of 90[°]
Third gas ejection port group Z1: A total of four gas ejection ports 24c arranged at intervals of 90[°]
Third gas ejection port group Z2: A total of four gas ejection ports 24c arranged at intervals of 90[°]
Third gas ejection port group Z3: A total of four gas ejection ports 24c arranged at intervals of 90[°]

That is, in the disk-shaped gas generator 1B of the present embodiment, the plurality of gas ejection ports 24 have rotational symmetry with an angle of 120[°] or less about the axis of the cylindrical portion 22 of the upper shell 20. A total of six gas ejection port groups X, Y1, Y2, each of which is composed of a plurality of gas ejection ports having the same opening pressure and are evenly arranged along the circumferential direction of the tubular portion 22 so as to have It is composed only of Z1, Z2 and Z3.

Here, as shown in FIG. 9, in the disk-shaped gas generator 1B of the present embodiment, when a perpendicular line PL is drawn from the maximum outer shape position A of the flange portion 23 to the axis O of the cylindrical portion 22 ( 9 representatively shows a case where a perpendicular line PL is drawn from one of the four maximum outer shape positions A), the gas ejection port 24 is arranged at a position closest to the perpendicular line PL. However, the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c other than the first gas ejection port 24a having the largest opening area.

More specifically, when viewed along the axis O of the tubular portion 22, the tubular portion 22 is not provided with the gas ejection port 24 at a position overlapping the perpendicular PL (that is, the perpendicular None of the plurality of gas ejection ports 24a to 24c are arranged at a position on the plane containing PL and the axis O of the cylindrical portion 22), and at the intersection of these cylindrical portions 22 and the perpendicular PL A third gas ejection port 24c is arranged at the closest position. As a result, the gas ejection port 24 located closest to the perpendicular PL is the third gas ejection port having the smallest opening area among the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c. A gas ejection port 24c is provided.

FIG. 10 is a diagram schematically showing the degree of deformation of the main part of the housing during operation of the disk-type gas generator according to the present embodiment. Next, with reference to FIG. 10, the degree of deformation of the main portion of the housing during operation of the disk-shaped gas generator 1B of this embodiment will be described. The cross section shown in FIG. 10 is the cross section of the housing of the disk-shaped gas generator 1B according to the present embodiment taken along the line XX shown in FIG.

Referring to FIG. 9, in disk-shaped gas generator 1B according to the present embodiment, a region in which none of the plurality of gas ejection ports 24 are arranged is circumferentially arranged along tubular portion 22. A fixed amount is formed, and is arranged so as to include the intersection of the cylindrical portion 22 and the perpendicular line PL, and the gas ejection port 24 arranged at the position closest to the perpendicular line PL is the first gas outlet 24 having the smallest opening area. It is configured to have three gas ejection ports 24c. Therefore, the mechanical strength of the cylindrical portion 22 is relatively high in the portion near the intersection with the perpendicular line PL of the cylindrical portion 22 as compared with other portions.

Therefore, as shown in FIG. 10, during operation of the disk-type gas generator 1B in the present embodiment, the portion of the region R corresponding to the maximum outer shape position A of the flange portion 23 is restrained by the flange portion 23. Although the force acts strongly, a relatively small deformation occurs in the portion of the cylindrical portion 22 corresponding to the portion in question (that is, a small amount of deformation as indicated by D2 in the drawing (that is, D2<D1 (D1 6(B))) is generated in the tubular portion 22), and as a result, the stress concentration generated in the relevant portion of the region R can be dramatically reduced.

Therefore, in the disk-shaped gas generator 1B of the present embodiment, the thickness of the upper shell 20 can be made relatively thinner than in the disk-shaped gas generator 1A of the first embodiment described above. As a result, further miniaturization and weight reduction can be achieved.

Here, the disk-shaped gas generator 1B in this embodiment is of a type that inflates and deploys a standard-sized airbag as described above, and the outer cylindrical portion 22 of the upper shell 20 is The diameter is designed to be, for example, 60.4 [mm], and the thickness (board thickness) of the tubular portion 22 is designed to be, for example, 1.1 [mm].

In this case, the length L1 and the width W1 of the first gas ejection port 24a are set to, for example, 4.0 [mm] and 1.9 [mm], respectively, and the length L2 and the width W1 of the second gas ejection port 24b are set to Width W2 is set to, for example, 3.3 [mm] and 1.4 [mm], respectively, and length L3 and width W3 of third gas ejection port 24c are set, for example, to 2.5 [mm] and 1.3 [mm], respectively. It is set to [mm].

Even when this configuration is adopted, a total of 12 nozzles are included in one set of first gas ejection port group X, one set of third gas ejection port group Z1, and one set of second gas ejection port group Y2. are formed by a single punching process, and are included in one set of second gas ejection port group Y1, one set of third gas ejection port group Z2, and one set of third gas ejection port group Z3 By forming a total of 12 gas outlets in one punching process, it becomes possible to form all of the plurality of gas outlets 24 in a total of two punching processes. Minimization of the manufacturing cost can be realized while considering the restrictions.

(Embodiment 3)
11 is a cross-sectional view of the upper shell of a disk-shaped gas generator according to Embodiment 3 of the present invention, and FIG. 12 is an enlarged view of the first to third gas ejection ports shown in FIG. 11. FIG. A disk-shaped gas generator 1C according to Embodiment 3 of the present invention will be described below with reference to FIGS. 11 and 12. FIG.

Unlike the disk-shaped gas generator 1B according to the second embodiment described above, the disk-shaped gas generator 1C according to the present embodiment is of a type that inflates and deploys a compact airbag smaller than the standard size. As shown in FIG. 11, the cylindrical portion 22 of the upper shell 20 is provided with a smaller number of gas ejection ports 24 than in the disk-shaped gas generator 1B of the second embodiment described above. .

Specifically, as shown in FIG. 11, the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c are arranged along the circumferential direction of the cylindrical portion 22 of the upper shell 20. (however, a rule different from the rule shown in the above-described second embodiment) is arranged in a row. More specifically, the plurality of gas ejection ports 24 are 16 in total and are arranged at predetermined angles along the circumferential direction of the cylindrical portion 22 of the upper shell 20 .

The number of the first gas ejection ports 24 a is four, and they are arranged along the circumferential direction of the cylindrical portion 22 of the upper shell 20 at intervals of 90[°]. The number of the second gas ejection ports 24b is eight, and the number of the second gas ejection ports 24b is 30[°], 60[°], 30[°], 60[°] along the circumferential direction of the cylindrical portion 22 of the upper shell 20. , , and so on. The number of the third gas ejection ports 24c is four, and they are arranged along the circumferential direction of the tubular portion 22 of the upper shell 20 at intervals of 90[°].

Here, the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c are arranged along the circumferential direction of the tubular portion 22 of the upper shell 20. The gas ejection openings 24c, the second gas ejection openings 24b, and the second gas ejection openings 24b are arranged in this order such that four sets are repeated. As a result, the plurality of gas ejection ports 24 are arranged so as not to overlap each other in the circumferential direction of the cylindrical portion 22 of the upper shell 20 .

Note that each gas arranged in the order of the first gas ejection port 24a, the third gas ejection port 24c, the second gas ejection port 24b, the second gas ejection port 24b, the first gas ejection port 24a, . . . The arrangement intervals between the ejection ports 24 are 21[°], 9[°], 30[°], 30[°], .

Here, referring to FIG. 11, disk-shaped gas generators 1C according to the present embodiment are configured to have the same shape and the same opening area so as to have the same opening pressure. In the case of focusing on the gas ejection openings that are formed and grasping them as a group of gas ejection openings according to their formation positions, the plurality of gas ejection openings described above can be obtained only by the following multiple sets of gas ejection opening groups. 24 can be seen to be configured. As described above, the gas ejection port group is determined so that as many gas ejection ports as possible form one set of gas ejection port groups.

First gas ejection port group X: a total of four gas ejection ports 24a arranged at intervals of 90[°]
Second gas ejection port group Y1: a total of four gas ejection ports 24b arranged at intervals of 90[°]
Second gas ejection port group Y2: A total of four gas ejection ports 24b arranged at intervals of 90[°]
Third gas ejection port group Z: a total of four gas ejection ports 24c arranged at intervals of 90[°]

That is, in the disk-shaped gas generator 1C of the present embodiment, the plurality of gas ejection ports 24 have rotational symmetry with an angle of 120[°] or less about the axis of the cylindrical portion 22 of the upper shell 20. A total of four gas ejection port groups X, Y1, Y2, each consisting of a plurality of gas ejection ports having the same opening pressure and arranged evenly along the circumferential direction of the cylindrical portion 22 so as to have Consists only of Z.

Here, as shown in FIG. 11, in the disk-shaped gas generator 1C according to the present embodiment as well, when a perpendicular line PL is drawn from the maximum outer shape position A of the flange portion 23 to the axis O of the cylindrical portion 22 ( FIG. 11 representatively illustrates the case where a perpendicular line PL is drawn from one of the four maximum outer shape positions A), the gas ejection port 24 arranged at the position closest to the perpendicular line PL. However, the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c other than the first gas ejection port 24a having the largest opening area.

More specifically, when viewed along the axis O of the tubular portion 22, the tubular portion 22 is not provided with the gas ejection port 24 at a position overlapping the perpendicular PL (that is, the perpendicular None of the plurality of gas ejection ports 24a to 24c are arranged at a position on the plane containing PL and the axis O of the cylindrical portion 22), and at the intersection of these cylindrical portions 22 and the perpendicular PL The second gas ejection port 24b is arranged at the closest position. As a result, the gas ejection port 24 located closest to the perpendicular PL has the second smallest opening area among the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c. It is set as the 2nd gas ejection port 24b.

Therefore, by using the disk-type gas generator 1C of the present embodiment, a predetermined portion ( In particular, the occurrence of stress concentration in the portion corresponding to the maximum outer shape position A of the flange portion 23 in the region R described above can be dramatically reduced. Therefore, by adopting this configuration, the thickness of the upper shell 20 can be made relatively thin, and as a result, a reduction in size and weight can be achieved.

Here, as described above, the disk-shaped gas generator 1C in the present embodiment is of a type that inflates and deploys a small-sized airbag smaller than the standard size. The outer diameter of the portion 22 is designed to be, for example, 57.5 [mm], and the thickness (board thickness) of the cylindrical portion 22 is designed to be, for example, 1.1 [mm].

In this case, referring to FIG. 12, the length L1 and the width W1 of the first gas ejection port 24a are set to, for example, 3.5 [mm] and 2.1 [mm], respectively, and the second gas ejection port 24a The length L2 and width W2 of the outlet 24b are set to 2.6 [mm] and 1.4 [mm], respectively, and the length L3 and width W3 of the third gas ejection port 24c are set to 2.4 [mm], respectively. It is set to [mm] and 1.2 [mm].

Even when this configuration is adopted, a total of 12 gas ejection ports included in one set of the first gas ejection port group X and two sets of the second gas ejection port groups Y1 and Y2 are punched once. A total of four gas ejection ports included in one set of the third gas ejection port group Z are formed by one punching process, so that a total of two punching processes are performed to form a plurality of gas ejection holes. It becomes possible to form all of the individual gas ejection ports 24, and the minimization of the manufacturing cost can be realized in consideration of the restrictions of the press machine.

(Embodiment 4)
FIG. 13 is a cross-sectional view of the upper shell of a disk-shaped gas generator according to Embodiment 4 of the present invention, and FIG. 14 is an enlarged view of the first through third gas ejection ports shown in FIG. A disk-shaped gas generator 1D according to Embodiment 4 of the present invention will be described below with reference to FIGS. 13 and 14. FIG.

Unlike the disk-shaped gas generator 1B of the second embodiment described above, the disk-shaped gas generator 1D in this embodiment is of a type that inflates and deploys a large-sized airbag that is larger than the standard size. As shown in FIG. 13, the cylindrical portion 22 of the upper shell 20 is provided with a larger number of gas ejection ports 24 than in the disk-shaped gas generator 1B of the second embodiment described above. .

Specifically, as shown in FIG. 13, the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c are arranged along the circumferential direction of the cylindrical portion 22 of the upper shell 20. (however, a rule different from the rule shown in the above-described second embodiment) is arranged in a row. More specifically, a total of 32 gas ejection ports 24 are arranged along the circumferential direction of the tubular portion 22 of the upper shell 20 at predetermined angles.

The number of the first gas ejection ports 24a is eight, and the number of the first gas ejection ports 24a is 70[°], 20[°], 70[°], 20[°] along the circumferential direction of the tubular portion 22 of the upper shell 20. , , and so on. The number of the second gas ejection ports 24b is eight, and the number of the second gas ejection ports 24b is 30[°], 60[°], 30[°], 60[°] along the circumferential direction of the cylindrical portion 22 of the upper shell 20. , , and so on. The number of the third gas ejection ports 24 c is 16, and the number of the third gas ejection ports 24 c is 20 [°], 10 [°], 20 [°], 40 [°] along the circumferential direction of the cylindrical portion 22 of the upper shell 20 . , 20[°], 10[°], 20[°], 40[°], .

Here, the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c are arranged along the circumferential direction of the tubular portion 22 of the upper shell 20. The gas ejection port 24c, the second gas ejection port 24b, the third gas ejection port 24c, the third gas ejection port 24c, the second gas ejection port 24b, the third gas ejection port 24c, and the first gas ejection port 24a are arranged in this order. are arranged so as to be repeated four sets. As a result, the plurality of gas ejection ports 24 are arranged so as not to overlap each other in the circumferential direction of the cylindrical portion 22 of the upper shell 20 .

Note that the above-described first gas ejection port 24a, third gas ejection port 24c, second gas ejection port 24b, third gas ejection port 24c, third gas ejection port 24c, second gas ejection port 24b, third gas ejection port The intervals between the gas ejection ports 24 arranged in the order of the outlet 24c, the first gas ejection port 24a, the first gas ejection port 24a, . . . ], 10[°], 10[°], 10[°], 10[°], 10[°], 20[°], .

Here, referring to FIG. 13, disk-shaped gas generators 1D according to the present embodiment are configured to have the same shape and the same opening area so as to have the same opening pressure. In the case of focusing on the gas ejection openings that are formed and grasping them as a group of gas ejection openings according to their formation positions, the plurality of gas ejection openings described above can be obtained only by the following multiple sets of gas ejection opening groups. 24 can be seen to be configured. As described above, the gas ejection port group is determined so that as many gas ejection ports as possible form one set of gas ejection port groups.

First gas ejection port group X1: A total of four gas ejection ports 24a arranged at intervals of 90[°]
First gas ejection port group X2: A total of four gas ejection ports 24a arranged at intervals of 90[°]
Second gas ejection port group Y1: a total of four gas ejection ports 24b arranged at intervals of 90[°]
Second gas ejection port group Y2: A total of four gas ejection ports 24b arranged at intervals of 90[°]
Third gas ejection port group Z1: A total of four gas ejection ports 24c arranged at intervals of 90[°]
Third gas ejection port group Z2: A total of four gas ejection ports 24c arranged at intervals of 90[°]
Third gas ejection port group Z3: A total of four gas ejection ports 24c arranged at intervals of 90[°]
Third gas ejection port group Z4: A total of four gas ejection ports 24c arranged at intervals of 90[°]

That is, in the disk-shaped gas generator 1D according to the present embodiment, the plurality of gas ejection ports 24 have rotational symmetry with an angle of 120[°] or less about the axis of the cylindrical portion 22 of the upper shell 20. A total of 8 gas ejection port groups X1, X2, Y1, composed of a plurality of gas ejection ports having the same opening pressure, arranged evenly along the circumferential direction of the cylindrical portion 22 so as to have It is composed only of Y2, Z1, Z2, Z3 and Z4.

Here, as shown in FIG. 13, in the disk-shaped gas generator 1D according to the present embodiment as well, when a perpendicular line PL is drawn from the maximum outer shape position A of the flange portion 23 to the axis O of the cylindrical portion 22 ( 13 representatively shows a case where a perpendicular line PL is drawn from one of the four maximum outer shape positions A), the gas ejection port 24 arranged at a position closest to the perpendicular line PL. However, the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c other than the first gas ejection port 24a having the largest opening area.

More specifically, when viewed along the axis O of the tubular portion 22, the tubular portion 22 is not provided with the gas ejection port 24 at a position overlapping the perpendicular PL (that is, the perpendicular None of the plurality of gas ejection ports 24a to 24c are arranged at a position on the plane containing PL and the axis O of the cylindrical portion 22), and at the intersection of these cylindrical portions 22 and the perpendicular PL A third gas ejection port 24c is arranged at the closest position. As a result, the gas ejection port 24 located closest to the perpendicular PL is the third gas ejection port having the smallest opening area among the first gas ejection port 24a, the second gas ejection port 24b, and the third gas ejection port 24c. A gas ejection port 24c is provided.

Therefore, by using the disk-shaped gas generator 1D in the present embodiment, a predetermined portion ( In particular, the occurrence of stress concentration in the portion corresponding to the maximum outer shape position A of the flange portion 23 in the region R described above can be dramatically reduced. Therefore, by adopting this configuration, the thickness of the upper shell 20 can be made relatively thin, and as a result, a reduction in size and weight can be achieved.

Here, as described above, the disk-shaped gas generator 1D in the present embodiment is of a type that inflates and deploys a large-sized airbag that is larger than the standard size. The outer diameter of the portion 22 is designed to be, for example, 70.0 [mm], and the thickness (board thickness) of the tubular portion 22 is designed to be, for example, 1.3 [mm].

In this case, referring to FIG. 14, the length L1 and the width W1 of the first gas ejection port 24a are set to 3.7 [mm] and 2.0 [mm], respectively, and the second gas ejection port 24a The length L2 and width W2 of the outlet 24b are set to 3.1 [mm] and 1.6 [mm], respectively, and the length L3 and width W3 of the third gas ejection port 24c are set to 2.5 [mm], respectively. [mm] and 1.4 [mm].

Even when this configuration is adopted, a total of 12 gas ejection ports included in one set of the first gas ejection port group X1 and two sets of the third gas ejection port groups Z2 and Z4 are punched once. A total of 12 gas ejection ports included in the two sets of third gas ejection port groups Z1 and Z3 and one set of the first gas ejection port group X2 are formed by one punching process. Furthermore, by forming a total of eight gas ejection ports included in the two sets of second gas ejection port groups Y1 and Y2 by one punching process, a plurality of gas ejection holes are formed by a total of three punching processes. of the gas ejection ports 24 can be formed, and the minimization of the manufacturing cost can be realized in consideration of the restrictions of the press machine.

(Other embodiments, etc.)
In the first to fourth embodiments of the present invention described above, the explanation was given by exemplifying the case where the upper shell is provided with a plurality of gas ejection ports and the flange portion. You can do it.

In addition, in the above-described first to fourth embodiments of the present invention, the case in which the housing is constituted by a pair of shell members consisting of an upper shell and a lower shell has been exemplified and explained. Of course, it is also possible to configure with the above shell members.

Further, in the first to fourth embodiments of the present invention described above, the case where three types of gas ejection ports are provided in the housing as a plurality of gas ejection ports including those having opening areas different from each other is exemplified. However, it may be configured with two types of gas ejection ports, or may be configured with four or more types of gas ejection ports.

Further, in the first to fourth embodiments of the present invention described above, the case where a plurality of gas ejection ports are provided in the housing according to a predetermined regular rule has been described as an example. Individual gas outlets do not necessarily have to be provided according to regular rules.

Furthermore, the shape, size, layout, and the like of the gas ejection ports disclosed in the first to fourth embodiments of the present invention described above can be changed variously without departing from the gist of the present invention.

Thus, the above-described embodiments disclosed this time are illustrative in all respects and are not restrictive. The technical scope of the present invention is defined by the scope of claims, and includes all changes within the meaning and scope of equivalents to the description of the scope of claims.

1A to 1D Disk-type gas generator 10 Lower shell 11 Bottom plate 12 Cylindrical part 13 Protruding cylindrical part 14 Recess 15 Opening 20 Upper shell 21 Top plate 22 Cylindrical Part 23 Flange 24 Gas ejection port 24a First gas ejection port 24b Second gas ejection port 24c Third gas ejection port 25 Through hole 26 Seal tape 28 Gap 30 Holding portion 31 Inside Coating Part 32 Outer Covering Part 33 Connecting Part 34 Female Connector Part 40 Ignitor 41 Ignition Part 42 Terminal Pin 50 Cup-shaped Member 51 Top Wall Part 52 Side Wall Part 53 Extension Part 54 Tip Part 55 Transfer Chamber 56 Transfer Charge 60 Combustion Chamber 61 Gas Generating Agent 70 Lower Side Support Member 71 Bottom Part 72 Contact Part 73 Tip Part 80 Upper Side Support Member 81 Bottom Part 82 Contact contact portion, 85 cushion material, 90 filter, A maximum outline position, O axis, PL vertical.

Claims (4)

a housing having a peripheral wall portion, a top plate portion and a bottom plate portion, wherein both axial ends of the peripheral wall portion are closed by the top plate portion and the bottom plate portion;
a gas generating agent that is disposed inside the housing and that generates gas by burning;
an igniter assembled to the housing for burning the gas generating agent;
The housing is configured by combining and joining a plurality of shell members,
One of the plurality of shell members includes a tubular portion forming at least a portion of the peripheral wall portion, and a flange portion extending continuously radially outward from one axial end of the tubular portion. has at least
The cylindrical portion is provided with a plurality of gas ejection ports including those having opening areas different from each other,
The flange portion is configured in a shape such that the distance from the axis of the cylindrical portion to the outer edge of the flange portion is non-uniform,
When a perpendicular to the axis of the tubular portion is drawn from the maximum outer shape position, which is the farthest position from the axis of the tubular portion, on the outer edge of the flange portion, the perpendicular and the axis of the tubular portion None of the plurality of gas ejection ports are arranged at a position on a plane containing , satisfy the condition that none of the plurality of gas ejection ports have the largest opening area,
A plurality of the maximum outer shape positions exist along the circumferential direction of the tubular portion,
The gas generator, wherein the conditions are satisfied in each of the portions corresponding to the plurality of maximum outer shape positions. The flange portion is provided with a through hole for fixing the gas generator to an external member,
The distance from the axis of the cylindrical portion to the outer edge of the flange portion is larger in a portion of the flange portion provided with the through hole than in a portion of the flange portion not provided with the through hole. 2. The gas generator of claim 1, wherein 3. The gas generator according to claim 1, wherein said plurality of gas ejection ports are arranged in a row along the circumferential direction of said tubular portion. The housing includes, as the plurality of shell members, a bottomed cylindrical upper shell forming the top plate portion and the peripheral wall portion close to the top plate portion, and the bottom plate portion and the peripheral wall portion close to the bottom plate portion. and a bottomed cylindrical lower shell that constitutes
The cylindrical portion provided with the plurality of gas ejection ports is defined by the upper shell of the portion forming the peripheral wall portion near the top plate portion,
The flange portion extends from an end portion of the upper shell on the bottom plate portion side of the portion forming the peripheral wall portion near the top plate portion,
By inserting the lower shell in the portion forming the peripheral wall portion closer to the bottom plate portion into the upper shell portion forming the peripheral wall portion closer to the top plate portion, the upper shell and the Combined with the lower shell,
4. The gas generator according to any one of claims 1 to 3 , wherein said igniter is attached to said lower shell of a portion constituting said bottom plate portion.

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