JP7462518B2 - Gas generator - Google Patents

Description

The present invention relates to a gas generator that is configured so that compressed gas sealed in a tank chamber provided inside a housing is ejected to the outside when an igniter is activated.

A gas generator incorporated in an airbag device, which is a passenger protection device for automobiles, etc., is configured so that when a vehicle crashes, an igniter is ignited by electricity from a control unit separately installed in the vehicle, which causes a large amount of gas to be instantly released to the outside, thereby inflating and deploying the airbag. Based on the gas release mechanism, such gas generators are broadly classified into pyrolytic gas generators, stored gas generators, and hybrid gas generators.

A pyrotechnic gas generator is a device in which a gas generating agent is contained inside a housing, and the gas generating agent is ignited and burned by the activation of an igniter, thereby generating a large amount of gas that is released to the outside.

A stored-type gas generator is a device in which compressed gas is sealed inside a housing, and a rupture disk that seals the compressed gas bursts when an igniter is activated, thereby releasing the compressed gas to the outside.

A hybrid gas generator is configured such that compressed gas is sealed inside a housing, and a heat generating agent is also contained inside the housing. The rupture disk that seals the compressed gas is ruptured by the operation of an igniter, and the heat generating agent is ignited and burned by the operation of the igniter, so that the compressed gas is released to the outside while the energy loss that may occur due to the adiabatic expansion of the compressed gas is compensated for by the heat generated by the combustion of the heat generating agent.

Of the various gas generators mentioned above, examples of documents disclosing the specific structure of a stored-type gas generator include JP 2003-182506 A (Patent Document 1), and examples of documents disclosing the specific structure of a hybrid-type gas generator include JP 2016-68658 A (Patent Document 2) and JP 2009-51236 A (Patent Document 3).

Of these, the stored type gas generator disclosed in Patent Document 1 and the hybrid type gas generator disclosed in Patent Document 2 have a structure generally referred to as a reverse flow structure, in which a communication hole is provided in a partition that separates a tank chamber in which compressed gas is sealed from an ignition chamber in which an igniter is housed, and a gas outlet is provided in a housing in a portion that defines the ignition chamber. In the stored type gas generator and hybrid type gas generator with the reverse flow structure, only the communication hole of the communication hole and the gas outlet is provided so as to face the tank chamber, so that the above-mentioned rupture disk is provided so as to close this communication hole, and the gas outlet is only closed by a sealing member that airtightly seals the ignition chamber from the outside.

On the other hand, the hybrid gas generator disclosed in the above-mentioned Patent Document 3 has a structure generally referred to as a blow-down structure, in which a communication hole is provided in a partition that separates a tank chamber containing compressed gas from an ignition chamber housing an igniter, and a gas outlet is provided in a housing that defines the tank chamber. In this hybrid gas generator with a blow-down structure, the communication hole and the gas outlet are both provided to face the tank chamber, and therefore a pair of the above-mentioned rupture discs are provided to individually close these communication holes and gas outlets.

Here, in the stored type gas generators and hybrid type gas generators disclosed in the above Patent Documents 1 to 3, the rupture discs that block the communication holes provided in the partition are all fixed to the partition by resistance welding. This resistance welding is performed by applying an electric current to the rupture disc while the rupture disc is in contact with the partition under pressure, generating Joule heat due to electrical resistance, which melts and joins them locally.

In the stored type gas generator and hybrid type gas generator described above, it is necessary to seal compressed gas in a tank chamber provided in the housing. One method of sealing this compressed gas is known, for example, from the method disclosed in JP 2000-227199 A (Patent Document 4).

The method of sealing compressed gas disclosed in Patent Document 4 involves providing a gas inlet in advance in the portion of the peripheral wall of the cylindrical member that constitutes the housing that defines the tank chamber, and after sending gas into the tank chamber through the gas inlet, welding a sealing pin to the cylindrical member so that the gas inlet is closed by the sealing pin.

JP 2003-182506 A JP 2016-68658 A JP 2009-51236 A JP 2000-227199 A

As mentioned above, in order to join the rupture disc to the partition by resistance welding, it is important to ensure that they are in contact with each other while preventing the contact area from becoming larger than necessary. For this reason, in the above Patent Documents 1 to 3, an uneven shape is imparted to the periphery of the portion of the partition where the communication holes are provided, so that the contact area between the partition and the rupture disc is a predetermined size.

However, in order to give the partition such an uneven shape, additional processing such as cutting would be required when manufacturing the partition, resulting in increased manufacturing costs. Therefore, from the perspective of manufacturing stored-type gas generators and hybrid-type gas generators more inexpensively, it is necessary to improve the assembly structure of the rupture disc to the partition.

On the other hand, when manufacturing a stored type gas generator or a hybrid type gas generator by adopting the method of sealing compressed gas as disclosed in the above-mentioned Patent Document 4, it is necessary to provide a structural part used only for sealing compressed gas at a specified part of the housing (i.e., a gas injection port provided on the peripheral wall of the above-mentioned cylindrical member, a sealing pin that closes the gas injection port, and its welded part, etc.), which leads to a complicated configuration of the gas generator itself, an increase in the number of parts, and complicated assembly work, resulting in problems such as increased manufacturing costs.

Therefore, the present invention has been made in consideration of the above-mentioned problems, and aims to make it possible to manufacture stored-type gas generators and hybrid-type gas generators more easily and inexpensively.

A gas generator according to the present invention includes an igniter and a housing. The housing has an ignition chamber facing the igniter and a tank chamber in which compressed gas is sealed, and is provided with a gas outlet that opens during operation. The housing has a holder to which the igniter is assembled, a first casing that defines the ignition chamber together with the holder, and a second casing that defines the tank chamber together with the first casing. The first casing has a first case body made of a single cylindrical member with a bottom including a cylindrical first peripheral wall portion having one axial end configured as a first open end and a bottom wall portion that closes the other axial end of the first peripheral wall portion. The second casing has a second case body including at least a cylindrical second peripheral wall portion having one axial end configured as a second open end. The first open end is closed by the holder, and the second open end is closed by the bottom wall portion. The bottom wall portion is provided with a through hole communicating with the ignition chamber and the tank chamber, and a rupture member capable of being ruptured due to the operation of the igniter is provided on the bottom wall portion so as to close the through hole. The rupture member is composed of a single bottomed cylindrical member including a cylindrical fixing portion which is inserted into the through hole and fixed by welding its outer circumferential surface to the wall surface of the bottom wall portion at a portion defining the through hole, and a plate-shaped rupture portion which closes one axial end of the fixing portion. The rupture member has a shape that allows it to be inserted into the through hole from the ignition chamber side. The through hole has a tapered shape in which the inner diameter becomes smaller from the ignition chamber side toward the tank chamber side, and the fixing portion has a tapered shape in which the outer diameter becomes smaller from the ignition chamber side toward the tank chamber side in correspondence with the tapered shape of the through hole.

In the gas generator according to the present invention, the rupture member may be provided with a stopper portion that abuts against the main surface of the bottom wall portion on the ignition chamber side to restrict the rupture member from moving toward the tank chamber side.

In the gas generator according to the present invention, it is preferable that the rupture portion is located at the end of the fixed portion on the tank chamber side.

In the gas generator according to the present invention, the outer surface of the annular corner portion connecting the fixing portion and the rupture portion may be configured as a curved surface.

In the gas generator according to the present invention, the ignition chamber may be filled with a heat generating agent that generates high-temperature heat when burned.

In the gas generator according to the present invention, the second case body may be configured as a cylindrical member in which the other axial end of the second peripheral wall portion is configured as a third open end, and in that case, the second casing may further have a nozzle body that closes the third open end and in which the gas outlet is provided.

In the gas generator according to the present invention, the second case body may be constructed of a single cylindrical member with a bottom including a closing portion that closes the other axial end of the second peripheral wall portion, and in that case, the gas outlet may be provided in the first peripheral wall portion.

The present invention makes it possible to manufacture stored-type gas generators and hybrid-type gas generators more easily and inexpensively.

1 is a schematic cross-sectional view of a hybrid gas generator according to a first embodiment. FIG. 2 is an enlarged view of the igniter assembly and the ignition chamber shown in FIG. 1 . FIG. 2 is an enlarged view of the vicinity of the nozzle assembly shown in FIG. 1 . 2 is a schematic diagram showing an assembly structure of a rupture member to a first casing in the hybrid gas generator shown in FIG. 1 . FIG. FIG. 4 is a flow diagram showing a manufacturing method of the hybrid gas generator according to the first embodiment. 6A to 6C are schematic cross-sectional views showing a process of assembling a second casing and attaching the second casing to a first casing in the manufacturing flow shown in FIG. 5 . 6 is a schematic cross-sectional view showing a positioning step of a first casing relative to a head portion of the compressed gas charging device in the manufacturing flow shown in FIG. 5 . 6 is a schematic cross-sectional view showing a vacuum drawing step in the manufacturing flow shown in FIG. 5 . 6 is a schematic cross-sectional view showing a gas filling step in the manufacturing flow shown in FIG. 5. 6 is a schematic cross-sectional view showing a step of assembling a rupturable member to a first casing in the manufacturing flow shown in FIG. 5 . 6 is a schematic cross-sectional view showing a step of assembling the igniter assembly to the first casing in the manufacturing flow shown in FIG. 5 . FIG. FIG. 13 is a schematic diagram showing an assembly structure of a rupture member to a first casing in a hybrid gas generator according to a first modified example based on the first embodiment. FIG. 13 is a schematic diagram showing an assembly structure of a rupture member to a first casing in a hybrid gas generator according to a second modified example based on the first embodiment. FIG. 13 is a schematic diagram showing an assembly structure of a rupture member to a first casing in a hybrid gas generator according to a third modified example based on the first embodiment. FIG. 13 is a schematic diagram showing an assembly structure of a rupture member to a first casing in a hybrid gas generator according to a fourth modified example based on the first embodiment. FIG. 13 is a schematic diagram showing an assembly structure of a rupture member to a first casing in a hybrid gas generator according to a fifth modified example based on the first embodiment. FIG. 13 is a schematic diagram showing an assembly structure of a rupture member to a first casing in a hybrid gas generator according to a sixth modified example based on the first embodiment. FIG. 11 is a schematic cross-sectional view of a stored-type gas generator according to a second embodiment. 19 is an enlarged view of the vicinity of the igniter assembly and the ignition chamber shown in FIG. 18 and the vicinity of the closing portion of the second casing. FIG. FIG. 11 is a schematic cross-sectional view of a hybrid gas generator according to related embodiment 1. FIG. 21 is an enlarged view of the igniter assembly and the ignition chamber shown in FIG. 20 . 21 is a schematic diagram showing an assembly structure of a sealing portion assembly to a first casing in the hybrid type gas generator shown in FIG. 20. FIG. 11 is a flow chart showing a method for manufacturing a hybrid gas generator according to related aspect 1. 24 is a schematic cross-sectional view showing a positioning step of the first casing relative to the head portion of the compressed gas charging device in the manufacturing flow shown in FIG. 23. 24 is a schematic cross-sectional view showing a step of assembling a sealing portion assembly to a first casing in the manufacturing flow shown in FIG. 23. FIG. 13 is a schematic diagram showing an assembly structure of a sealing portion assembly to a first casing in a hybrid type gas generator according to a seventh modified example based on related form 1. FIG. 13 is a schematic diagram showing an assembly structure of a sealing portion assembly to a first casing in a hybrid gas generator according to an eighth modified example based on related form 1. FIG. 11 is a schematic cross-sectional view of a stored-type gas generator according to related embodiment 2. 29 is an enlarged view of the igniter assembly and the ignition chamber shown in FIG. 28 and the vicinity of the closing portion of the second casing. FIG.

The following describes in detail an embodiment of the present invention with reference to the drawings. The following embodiment illustrates the application of the present invention to a hybrid gas generator or a stored gas generator as a cylinder-type gas generator incorporated in a side airbag device. In the following embodiments, the same or common parts are denoted by the same reference numerals in the drawings, and their description will not be repeated.

(Embodiment 1)
Fig. 1 is a schematic cross-sectional view of a hybrid gas generator according to embodiment 1. Fig. 2 is an enlarged view of the vicinity of an igniter assembly and an ignition chamber of the hybrid gas generator shown in Fig. 1, and Fig. 3 is an enlarged view of the vicinity of a nozzle assembly. First, the configuration of a hybrid gas generator 1A according to the present embodiment will be described with reference to Figs. 1 to 3. Note that hybrid gas generator 1A according to the present embodiment has a so-called blow-down structure.

As shown in FIG. 1, the hybrid gas generator 1A has an overall long, generally cylindrical outer shape. The hybrid gas generator 1A mainly comprises a first casing 10, a second casing 20, an igniter assembly 30, a nozzle assembly 40, a rupture member 50, a heat generating agent 60, and compressed gas (not shown in the figure).

The housing of the hybrid gas generator 1A is composed of a holder 31 included in the igniter assembly 30, a first casing 10, and a second casing 20. Of these, the first casing 10 is composed of a first case body 11, and the second casing 20 is composed of a second case body 21 and a nozzle body 41 included in the nozzle assembly 40.

The space inside the housing is divided into an ignition chamber S1, which is mainly defined by the holder 31 and the first case body 11, and a tank chamber S2, which is mainly defined by the first case body 11, the second case body 21, and the nozzle body 41. The ignition chamber S1 is filled with a heat generating agent 60, and the tank chamber S2 is filled with compressed gas.

As shown in Figures 1 and 2, the first case body 11 is made of a single cylindrical member with a bottom, including a first peripheral wall portion 11a and a bottom wall portion 11b. The first peripheral wall portion 11a has a cylindrical shape, and one axial end thereof is configured as a first open end 11a1. The bottom wall portion 11b has a disk shape with a through hole 11b1 in the center, and closes the other axial end of the first peripheral wall portion 11a.

Through hole 11b1 is provided in bottom wall portion 11b so as to communicate with both ignition chamber S1 and tank chamber S2. Through hole 11b1 is used as a gas inlet when sealing compressed gas in tank chamber S2, and is closed by rupture member 50 after the compressed gas is injected. Note that through hole 11b1 is also the portion where a communication hole is formed that communicates between ignition chamber S1 and tank chamber S2 when hybrid gas generator 1A is in operation.

The first case body 11 functions as a pressure bulkhead and is made of a metal member such as stainless steel or steel. Here, since a portion of the first case body 11 will be exposed to compressed gas for a long period of time, it is preferable that it is made of a steel material to which chromium, manganese, molybdenum, niobium, nickel, etc. are added so that it has excellent corrosion resistance.

As shown in Figures 1 to 3, the second case body 21 is made of a single cylindrical member including the second peripheral wall portion 21a. The second peripheral wall portion 21a has a cylindrical shape, with one axial end thereof configured as the second open end 21a1 and the other axial end thereof configured as the third open end 21a2.

The second case body 21 is fixed to the first case body 11. More specifically, the second case body 21 is press-fitted by inserting the second open end 21a1 of the second peripheral wall portion 21a into the closed end of the first peripheral wall portion 11a of the first case body 11 (i.e., the axial end of the first peripheral wall portion 11a closed by the bottom wall portion 11b), and is fixed by joining the first case body 11 and the second case body 21 at or near the contact portion between them. Here, electron beam welding, laser welding, resistance welding, friction welding, etc. can be suitably used to join the first case body 11 and the second case body 21.

As a result, the second open end 21a1 of the second case body 21 is closed by the bottom wall portion 11b of the first case body 11. This also results in the first case body 11 and the second case body 21 being positioned coaxially, and the first peripheral wall portion 11a and the second peripheral wall portion 21a form the peripheral wall of the housing of the hybrid gas generator 1A as a whole.

The second case body 21 functions as a pressure bulkhead and is made of a metal member such as stainless steel or steel. Here, since the second case body 21 will be exposed to compressed gas for a long period of time, it is preferable that it is made of a steel material to which chromium, manganese, molybdenum, niobium, nickel, etc. are added so that it has excellent corrosion resistance.

The method of fixing the second case body 21 to the first case body 11 is not limited to the above-mentioned methods using press-fitting and welding, and other fixing methods may be used.

As shown in Figures 1 and 2, the igniter assembly 30 has a holder 31, an igniter 32, and a resin molded portion 33. The igniter assembly 30 is made by fixing the holder 31 and the igniter 32 using the resin molded portion 33, and is configured as a pre-integrated part.

The holder 31 is made of a member having a substantially cylindrical outer shape and has a through-hole 31a extending along the axial direction. The through-hole 31a is the portion in which the igniter 32 is housed and in which the resin molded portion 33 is provided.

The holder 31 functions as a pressure bulkhead and is made of a metal member such as stainless steel or steel.

The igniter 32 is used to generate a flame and is made of a pyrotechnic device generally called a squib. The igniter 32 has an ignition section 32a and a pair of terminal pins 32b. The ignition section 32a contains an ignition charge that ignites and burns to generate a flame when activated, and a resistor (bridge wire) for igniting the ignition charge. The pair of terminal pins 32b are connected to the ignition section 32a to ignite the ignition charge.

More specifically, the ignition section 32a includes a squib cup formed in a cup shape, and a plug that closes the open end of the squib cup and through which a pair of terminal pins 32b are inserted and held. The resistor described above is attached so as to connect the tips of the pair of terminal pins 32b inserted into the squib cup, and an ignition charge is loaded into the squib cup so as to surround or be adjacent to the resistor.

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

When a collision is detected, a predetermined amount of current flows through the resistor via terminal pin 32b. When a predetermined amount of current flows through the resistor, Joule heat is generated in the resistor, and the ignition charge begins to burn. The high-temperature flame generated by the combustion explodes the squib cup that contains the ignition charge. The time from when the current flows through the resistor to when the igniter 32 is activated is generally 2 ms or less when nichrome wire is used for the resistor.

The resin molded portion 33 is made of a resin portion formed by injection molding (more specifically, so-called insert molding), and is fixed to both the holder 31 and the igniter 32. This resin molded portion 33 can be formed by using a mold during injection molding to pour a fluid resin material between the holder 31 and the igniter 32 so as to fill the space between them, and then solidifying it. As a result, the penetration portion 31a of the holder 31 is embedded between the igniter 32 and the resin molded portion 33, and the resin molded portion 33 ensures sealing properties in that area.

As the raw material for the resin molded portion 33 formed by injection molding, a resin material that has excellent heat resistance, durability, corrosion resistance, etc. after hardening is preferably selected and used. In this case, it is not limited to thermosetting resins such as epoxy resin, but it is also possible to use thermoplastic resins such as polybutylene terephthalate resin, polyethylene terephthalate resin, polyamide resin (e.g. nylon 6, nylon 66, etc.), polypropylene sulfide resin, polypropylene oxide resin, etc.

The resin molded portion 33 has a recess 33a that is exposed to the outside. A pair of terminal pins 32b of the igniter 32 are disposed inside the recess 33a. As a result, a female connector portion consisting of the recess 33a and the pair of terminal pins 32b is provided on the end face on one axial end side of the peripheral wall of the housing in which the igniter assembly 30 is located.

The female connector portion is a portion for receiving a male connector (not shown) of a harness for connecting the igniter 32 and a control unit (not shown). The female connector portion is exposed to the outside of the housing, and when the male connector described above is inserted into the female connector portion, electrical continuity is established between the core wire of the harness and the terminal pin 32b.

The method of fixing the igniter 32 to the holder 31 is not limited to the fixing method using the resin molded part 33 described above, and other fixing methods may be used.

The igniter assembly 30 is fixed to the first case body 11. More specifically, the igniter assembly 30 is fixed by inserting the holder 31 of the igniter assembly 30 into the first open end 11a1 of the first case body 11, and by joining the first case body 11 and the holder 31 at or near the contact portion between them. Here, electron beam welding, laser welding, resistance welding, friction welding, etc. can be suitably used to join the first case body 11 and the holder 31.

As a result, the first open end 11a1 of the first case body 11 is closed by the holder 31 (more precisely, the igniter assembly 30), and the ignition portion 32a of the igniter 32 assembled to the holder 31 faces the ignition chamber S1. This also results in the first case body 11 and the holder 31 being positioned coaxially, and the holder 31 forming one axial end of the peripheral wall of the housing of the hybrid gas generator 1A.

The method of fixing the igniter assembly 30 to the first case body 11 is not limited to the above-mentioned methods using press-fitting and welding, and other fixing methods may be used.

As shown in Figures 1 and 3, the nozzle assembly 40 has a nozzle body 41 and a rupture disc 42. The nozzle assembly 40 is configured as a pre-integrated part by joining the rupture disc 42 to the nozzle body 41.

The nozzle body 41 has a disk-shaped base portion 41a with a through hole in the center, and a cylindrical nozzle portion 41b with one end closed. The nozzle portion 41b protrudes from the center of the base portion 41a along the axial direction, and is positioned so that it extends toward the outside of the housing.

The nozzle body 41 functions as a pressure bulkhead and is made of a metal member such as stainless steel or steel. Here, since a portion of the nozzle body 41 will be exposed to compressed gas for a long period of time, it is preferable that the nozzle body 41 be made of a steel material to which chromium, manganese, molybdenum, niobium, nickel, etc. are added so that the steel has excellent corrosion resistance.

The nozzle body 41 has a hollow flow passage portion 41c inside. The flow passage portion 41c is composed of a through hole provided in the base portion 41a and a hollow portion provided in the nozzle portion 41b, and thus the flow passage portion 41c has an opening at one end that opens toward the tank chamber S2. The opening provided on the tank chamber S2 side of the flow passage portion 41c is closed by a rupture disc 42.

The peripheral wall of the nozzle portion 41b is provided with a plurality of gas outlets 41d, each of which is connected to the flow passage portion 41c. The gas outlets 41d are portions that open during operation of the hybrid gas generator 1A to eject gas to the outside, and are closed by the rupture disc 42 via the flow passage portion 41c.

The rupture disc 42 has a circular thin plate-like outer shape, and is fixed to the base portion 41a of the nozzle body 41 so as to close the opening provided on the tank chamber S2 side of the flow path portion 41c as described above. The rupture disc 42 can be ruptured due to the activation of the igniter 32 and the rupture of the rupture portion 52 of the rupture member 50 described later, and is preferably made of a metal member.

Here, since a portion of the rupture disc 42 is exposed to the compressed gas for a long period of time, it is preferable that the rupture disc 42 is made of a nickel alloy member formed from a thin metal plate such as SUS316 (JIS standard symbol) or Inconel (registered trademark) from the viewpoint of corrosion resistance. For example, a metal thin plate (e.g., about 200 [μm] thick) having heat resistance and corrosion resistance is preferably used as the rupture disc 42, and a thin plate made of stainless steel or Inconel alloy (Inconel 625) with the composition ratio of Ni: 10 [wt %], Cr: 23 [wt %], Mn: 6 [wt %], Mo: 2 [wt %], C: 0.01 [wt %], N: 0.5 [wt %], or other components is particularly preferably used.

The rupture plate 42 is fixed to the nozzle body 41 by joining it, for example, by electron beam welding, laser welding, resistance welding, etc.

The nozzle assembly 40 is fixed to the second case body 21. More specifically, the nozzle assembly 40 is fixed by inserting the nozzle body 41 of the nozzle assembly 40 into the third open end 21a2 of the second case body 21 and pressing it in, and by joining the second case body 21 and the nozzle body 41 at or near the contact portion between them. Here, electron beam welding, laser welding, resistance welding, friction welding, etc. can be suitably used to join the second case body 21 and the nozzle body 41.

As a result, the third open end 21a2 of the second case body 21 is closed by the nozzle body 41 (more precisely, the nozzle assembly 40), and the rupture disk 42 attached to the nozzle body 41 faces the tank chamber S2. This also results in the second case body 21 and the nozzle body 41 being positioned coaxially, and the nozzle body 41 forming the other axial end of the peripheral wall of the housing of the hybrid gas generator 1A.

The method of fixing the nozzle assembly 40 to the second case body 21 is not limited to the above-mentioned methods using press-fitting and welding, and other fixing methods may be used.

By having the above-mentioned configuration, in the hybrid gas generator 1A according to this embodiment, the space inside the housing is divided into two spaces in the axial direction by the bottom wall portion 11b of the first case body 11. Therefore, one of the spaces, the ignition chamber S1, is defined by the first peripheral wall portion 11a and the bottom wall portion 11b of the first case body 11 and the holder 31 (more precisely, the igniter assembly 30), and the other space, the tank chamber S2, is defined by the bottom wall portion 11b of the first case body 11, the second peripheral wall portion 21a of the second case body 21, and the nozzle body 41 (more precisely, the nozzle assembly 40).

As described above, the first case body 11 functions as a pressure partition, and therefore the bottom wall 11b of the first case body 11 also functions as a pressure partition, and functions as a partition that separates the ignition chamber S1 and the tank chamber S2. As described above, the bottom wall 11b of the first case body 11, which functions as a partition, is provided with a through hole 11b1 and a rupture member 50 that closes the through hole 11b1, the details of which will be described later.

Referring to Figures 1 and 2, as described above, the heat generating agent 60 is contained in the ignition chamber S1 defined by the first case body 11 and the igniter assembly 30.

Heat generating agent 60 is made of an agent that generates high-temperature heat by burning. Heat generating agent 60 supplies heat to the compressed gas to compensate for energy loss that may occur due to adiabatic expansion of the compressed gas when rupture member 50 and rupture disk 42 are ruptured during operation of hybrid gas generator 1A, and examples of the heat generating agent that can be used include a composition made of a metal powder/oxidizer represented by B/KNO ₃ , B/NaNO ₃ , Sr(NO ₃ ) ₂ or the like, a composition to which guanidine nitrate or nitroguanidine is added, a composition made of titanium hydride/potassium perchlorate, a composition made of B/5-aminotetrazole/potassium nitrate, a composition made of ammonium perchlorate/potassium perchlorate/nitroguanidine, a composition made of Sr(NO ₃ ) ₂ /nitroguanidine, and the like.

The heat generating agent 60 may be in a powder form or may be formed into a specific shape using a binder. The shape of the heat generating agent 60 formed using a binder may be, for example, granular, cylindrical, sheet, spherical, single-hole cylinder, multi-hole cylinder, tablet, or other various shapes.

On the other hand, referring to Figures 1 to 3, as described above, compressed gas is contained in the tank chamber S2 defined by the first case body 11, the second case body 21, and the nozzle assembly 40.

When the hybrid gas generator 1A is in operation, the rupture disk 42 bursts and the compressed gas is released to the outside, thereby inflating and deploying the airbag provided adjacent to the hybrid gas generator 1A. As the compressed gas, various inert gases can be used, such as helium gas, argon gas, neon gas, nitrogen gas, carbon dioxide gas, oxygen gas, etc.

Figure 4 is a schematic diagram showing the assembly structure of the rupture member to the first casing in the hybrid gas generator shown in Figure 1. Here, (A) shows the state before assembly, and (B) shows the state after assembly. Next, with reference to this Figure 4 and the above-mentioned Figure 2, the assembly structure of the rupture member 50 to the first casing 10 in the hybrid gas generator 1A according to this embodiment will be described.

2 and 4, the rupture member 50 is made of a single, bottomed, generally cylindrical member including a fixed portion 51 and a rupture portion 52. The fixed portion 51 has a generally cylindrical shape, and has a hollow portion 51a inside. The rupture portion 52 has a circular, thin plate shape. One axial end of the fixed portion 51 is open, and the other end is closed by the rupture portion 52. The rupture member 50 is such that its rupture portion 52 can be ruptured due to the activation of the igniter 32, and is preferably made of a metal member.

Here, since a portion of the rupture member 50 is exposed to the compressed gas for a long period of time, it is preferable that the rupture member 50 is made of a nickel alloy member formed from a thin metal plate such as SUS316 (JIS standard symbol) or Inconel (registered trademark) from the viewpoint of corrosion resistance. For example, a press-molded product formed by pressing a thin metal plate (e.g., about 200 μm thick) having heat resistance and corrosion resistance is preferably used as the rupture member 50, and a press-molded product made of stainless steel or Inconel alloy (Inconel 625) with the composition ratio of Ni: 10 [wt %], Cr: 23 [wt %], Mn: 6 [wt %], Mo: 2 [wt %], C: 0.01 [wt %], N: 0.5 [wt %], or other components is particularly preferably used.

The rupture member 50 is fixed to the first case body 11 in a state where it is inserted into the through hole 11b1 provided in the bottom wall portion 11b of the first case body 11. More specifically, as shown in FIG. 4, the rupture member 50 is inserted so that the outer peripheral surface of its fixing portion 51 abuts against the wall surface of the bottom wall portion 11b at the portion that defines the through hole 11b1, and is fixed to the first case body 11 by resistance welding in this state. As a result, the outer peripheral surface of the fixing portion 51 is joined to the wall surface of the bottom wall portion 11b.

The rupture member 50 is assembled by being inserted into the through hole 11b1 from the first open end 11a1 side of the first peripheral wall portion 11a as described below, so the rupture member 50 has a shape that allows it to be inserted into the through hole 11b1 from the first open end 11a1 side (i.e., from the ignition chamber S1 side).

Specifically, in this embodiment, the through hole 11b1 provided in the bottom wall portion 11b has a tapered shape in which the inner diameter becomes smaller from the ignition chamber S1 side toward the tank chamber S2 side, and the fixing portion 51 of the rupture member 50 has a tapered shape in which the outer diameter becomes smaller from the ignition chamber S1 side toward the tank chamber S2 side, corresponding to the above-mentioned tapered shape of the through hole 11b1.

By tapering the through hole 11b1 and the fixing portion 51 in this way, when the rupture member 50 is attached to the bottom wall portion 11b, it is possible to position and arrange the rupture member 50 with high precision relative to the bottom wall portion 11b, and it is possible to bring the outer peripheral surface of the fixing portion 51 into close contact with the above-mentioned wall surface of the bottom wall portion 11b, resulting in a predetermined contact area. Therefore, by performing resistance welding in this state, it is possible to reliably and stably fix the rupture member 50 to the bottom wall portion 11b.

In this embodiment, the rupture portion 52 is located at the end of the fixed portion 51 on the tank chamber S2 side. As a result, the rupture member 50 is arranged so that the outer surface of the rupture portion 52 faces the tank chamber S2. Therefore, from the viewpoint of improving the pressure resistance of the rupture member 50, it is preferable that the outer surface of the annular corner portion 53 connecting the fixed portion 51 and the rupture portion 52 is configured as a curved surface.

Next, the operation of the hybrid gas generator 1A according to the present embodiment having the above-mentioned configuration will be described with reference to the aforementioned Figures 1 to 3.

First, the igniter 32 is activated by receiving electricity from the control unit described above. When the igniter 32 is activated, the ignition charge filled in the ignition section 32a is heated by a resistor and ignited, and the ignition charge burns, causing the ignition section 32a to explode. As a result, the heat generating agent 60 contained in the ignition chamber S1 is ignited by the igniter 32 and burns.

The combustion of the ignition charge and heat generating agent 60 causes the pressure and temperature of the ignition chamber S1 to rise, which causes the rupture portion 52 of the rupture member 50 to rupture. As the rupture portion 52 ruptures, the ignition chamber S1 and the tank chamber S2 are connected via the through hole 11b1 provided in the bottom wall portion 11b of the first case body 11. At this time, the fixed portion 51 of the rupture member 50 remains without being burned, so more strictly speaking, the ignition chamber S1 and the tank chamber S2 are connected via the hollow portion 51a located inside the fixed portion 51.

Next, as the ignition chamber S1 and the tank chamber S2 communicate with each other, the pressure and temperature in the tank chamber S2 also rise, causing the rupture disc 42 to rupture in a portion facing the flow path 41c. As the rupture disc 42 ruptures, the tank chamber S2 and the multiple gas outlets 41d communicate with each other via the flow path 41c.

As a result, the compressed gas contained in the tank chamber S2 flows through the flow path 41c to the multiple gas outlets 41d, and is then ejected from the multiple gas outlets 41d to the outside.

The gas ejected from the multiple gas ejection ports 41d to the outside of the hybrid gas generator 1A is introduced into an airbag provided adjacent to the hybrid gas generator 1A, causing the airbag to inflate and deploy.

By configuring the hybrid gas generator 1A according to the present embodiment as described above, it is possible to join the bottom wall 11b and the rupture member 50 by resistance welding while maintaining the contact area between them at a predetermined size, without providing an uneven shape to the bottom wall 11b of the first case body 11, which serves as a partition between the ignition chamber S1 and the tank chamber S2, in order to set the contact area of the rupture member 50 with the bottom wall 11b at a predetermined size. This is because, as described above, the rupture member 50 is made of a substantially cylindrical member with a bottom, and is joined by resistance welding while inserted into the through hole 11b1 provided in the bottom wall 11b.

As a result, it is no longer necessary to perform additional processing such as cutting to create the uneven shape that was previously required, and the manufacturing process can be simplified and manufacturing costs can be reduced. Therefore, by making the hybrid gas generator 1A as described above, it is possible to manufacture it easily and inexpensively.

In addition, by using the hybrid gas generator 1A according to this embodiment, it is possible to reduce the weight while ensuring the pressure resistance of the housing. This point will be explained in detail below.

In a hybrid gas generator, an igniter is placed facing an ignition chamber formed inside the housing, which is filled with a heat generating agent. As the internal pressure of the ignition chamber rises significantly during operation, the part of the housing that defines the ignition chamber is required to have high pressure resistance. In addition, a tank chamber formed inside the housing is filled with compressed gas. Therefore, the part of the housing that defines the tank chamber is also required to have a considerable degree of pressure resistance.

Therefore, the housing that defines the ignition chamber and tank chamber must be made of a material with high mechanical strength and be sufficiently thick to ensure high pressure resistance, which results in an increase in the weight of the hybrid gas generator.

Generally, the pressure resistance required for the part of the housing that defines the ignition chamber is higher than the pressure resistance required for the part of the housing that defines the tank chamber. Therefore, if the thickness of the part of the housing that defines the tank chamber can be made thinner than the thickness of the part of the housing that defines the ignition chamber, the weight can be reduced accordingly.

In this regard, in the hybrid gas generator 1A according to this embodiment, of the parts constituting the peripheral wall of the housing and the parts constituting the partition, the peripheral wall of the part defining the ignition chamber S1 and the partition are constituted by a first case body 11 made of a single cylindrical member with a bottom, and the remaining peripheral wall of the part defining the tank chamber S2 is constituted by a second case body 21.

Therefore, by adopting this configuration, it is easy to make the thickness of the first peripheral wall portion 11a and the bottom wall portion 11b of the first case body 11 relatively thick while making the thickness of the second peripheral wall portion 21a of the second case body 21 relatively thin, thereby realizing a lightweight housing while suppressing an increase in the number of parts.

In addition, in the hybrid gas generator 1A according to this embodiment, among the housing walls that define the tank chamber S2 in which compressed gas is sealed, no opening is provided in the second peripheral wall portion 21a of the second case body 21, and no opening is provided in the bottom wall portion 11b of the first case body 11 other than the through hole 11b1 that is closed by the rupture member 50.

This characteristic configuration results from the fact that the hybrid gas generator 1A according to this embodiment is manufactured according to the manufacturing method for the hybrid gas generator according to this embodiment described below. In summary, when the compressed gas is sealed in the tank chamber S2, the through hole 11b1 provided in the bottom wall portion 11b of the first case body 11 is used as a gas injection port, and after the compressed gas is injected, the through hole 11b1 is closed by the rupture member 50.

The above points will be explained in more detail below while specifically explaining the manufacturing method of the hybrid gas generator according to this embodiment. Figure 5 is a flow diagram showing the manufacturing method of the hybrid gas generator according to this embodiment, and Figures 6 to 11 are schematic cross-sectional views of some of the steps shown in Figure 5.

As shown in FIG. 5, when manufacturing the hybrid gas generator 1A according to this embodiment, first, in step ST11, the igniter assembly 30 and the nozzle assembly 40 are each produced.

Specifically, the igniter 32 is fixed to the holder 31 using the resin molded portion 33 to produce the igniter assembly 30 as an integrated part, and the rupture disk 42 is welded to the nozzle body 41 by, for example, resistance welding to produce the nozzle assembly 40 as an integrated part.

Next, as shown in Figures 5 and 6, in step ST12, the second casing 20 is assembled and attached to the first casing 10.

Specifically, as shown in FIG. 6, the base portion 41a of the nozzle body 41 of the nozzle assembly 40 is inserted and pressed into the third open end 21a2 of the second peripheral wall portion 21a of the second case body 21, and then the nozzle body 41 is welded to the second case body 21 by, for example, laser welding, etc., thereby assembling the nozzle assembly 40 to the second case body 21. In this way, the second casing 20 is assembled.

Then, the second open end 21a1 of the second peripheral wall portion 21a of the second case body 21 is inserted and pressed into the closed end of the first peripheral wall portion 11a of the first case body 11 (i.e., the axial end portion of the first peripheral wall portion 11a closed by the bottom wall portion 11b), and then the second case body 21 is welded to the first case body 11 by, for example, laser welding, thereby assembling the second case body 21 to the first case body 11. This completes the assembly of the second casing 20 to the first casing 10.

Next, as shown in Figures 5 and 7, in step ST13, the first casing 10 is positioned relative to the head portion 110 of the compressed gas injection device 100.

As shown in FIG. 7, the compressed gas charging device 100 is configured by combining a gas filling device and a welding device, and has a block-shaped head portion 110. The head portion 110 includes a gas filling head 111 and a welding head 112, and the welding head 112 is slidably incorporated into the gas filling head 111.

An air passage 111a is provided inside the gas filling head 111 and is selectively connected to a gas supply source and a negative pressure source (not shown), and one end of the air passage 111a opens at the main surface 111b of the gas filling head 111.

On the other hand, the welding head 112 has a generally cylindrical outer shape and is slidably held by the gas filling head 111 as described above. Inside the welding head 112, a suction passage 112a connected to a negative pressure source (not shown) is provided, and one end of the suction passage 112a opens at the main surface 112b of the welding head 112.

Here, the main surface 111b of the gas filling head 111 and the main surface 112b of the welding head 112 are arranged parallel to each other, and when the welding head 112 is driven, the main surface 112b of the welding head 112 can move so as to protrude from the main surface 111b of the gas filling head 111. One end of the ventilation passage 111a that opens in the main surface 111b of the gas filling head 111 is arranged to surround the welding head 112.

The welding head 112 holds the rupturable member 50 in advance. More specifically, the open end of the fixed portion 51 on the side where the rupturable portion 52 is not located is placed in advance against the main surface 112b of the welding head 112, and in this state, the negative pressure source described above is driven to generate negative pressure in the suction path 112a, so that the rupturable member 50 is held by the welding head 112 (the suction direction by the negative pressure source is shown diagrammatically by arrow A in the figure).

In this state, the first open end 11a1 of the first peripheral wall portion 11a of the first case body 11 to which the second casing 20 was assembled in step ST12 is pressed against the main surface 111b of the gas filling head 111, thereby positioning the first casing 10 relative to the head portion 110 of the compressed gas filling device 100.

At this time, the end face on the first open end 11a1 side of the first peripheral wall portion 11a of the first case body 11 is abutted against the main surface 111b of the gas filling head 111, so that a closed space is formed by the bottom wall portion 11b of the first case body 11, which is provided with a through hole 11b1 as a gas injection port, the first peripheral wall portion 11a of the first case body 11, and the main surface 111b of the gas filling head 111 (see Figure 8).

At this time, the end of the welding head 112 holding the rupture member 50 is covered by the first open end 11a1 of the first peripheral wall portion 11a of the first case body 11, so that the rupture member 50 is held by the welding head 112 inside the closed space described above (see FIG. 8).

In addition, if a sealing member such as a packing is provided on the main surface 111b of the gas filling head 111 where the end face on the first open end 11a1 side of the first peripheral wall portion 11a of the first case body 11 is pressed, the airtightness between the closed space and the external space described above can be improved.

Next, as shown in Figures 5 and 8, in step ST14, a vacuum is drawn. This vacuum is drawn using the gas filling device described above that is equipped with a gas filling head 111.

Specifically, as shown in FIG. 8, the air passage 111a provided in the gas filling head 111 is connected to the negative pressure source and the negative pressure source is driven, so that the air in the closed space and the tank chamber S2 that communicates with the closed space via the through hole 11b1 is sucked in, and the sucked air is exhausted to the outside via the air passage 111a (in the figure, the suction direction by the negative pressure source is shown diagrammatically by arrow B). The vacuum drawing is performed until the pressure in the tank chamber S2 reaches a predetermined vacuum level.

Next, as shown in Figures 5 and 9, gas filling is performed in step ST15. This gas filling is performed by continuing to use the above-mentioned gas filling device equipped with the gas filling head 111.

Specifically, as shown in FIG. 9, the vent passage 111a provided in the gas filling head 111 is switched from the negative pressure source to the gas supply source and the gas supply source is driven, so that gas is fed into the closed space and the tank chamber S2 that communicates with the closed space via the through hole 11b1, and the fed gas is compressed, filling the tank chamber S2 with compressed gas (in the figure, the direction of gas fed by the gas supply source is indicated diagrammatically by arrow C). The gas filling is performed until the pressure in the tank chamber S2 reaches a predetermined high pressure state (for example, about 30 MPa to 90 MPa).

At this time, the above-mentioned one end of the ventilation passage 111a that opens on the main surface 111b of the gas filling head 111 functions as a gas delivery port 111a1 for delivering gas, and the gas delivered from the gas delivery port 111a1 is delivered to the tank chamber S2 from the through hole 11b1 as a gas inlet by passing through the above-mentioned closed space.

Next, as shown in Figures 5 and 10, in step ST16, the rupture member 50 is attached to the first casing 10. The rupture member 50 is attached using the above-mentioned welding device equipped with the welding head 112.

Specifically, as shown in FIG. 10, after the tank chamber S2 is filled with compressed gas in step ST15, the rupture member 50, which has been held by the welding head 112 inside the closed space described above, is moved by driving the welding head 112, and the rupture member 50 is inserted into the through hole 11b1 serving as a gas injection port. At that time, the rupture member 50 is positioned so that the outer peripheral surface of the fixing portion 51 of the rupture member 50 is in close contact with the wall surface of the bottom wall portion 11b that defines the through hole 11b1.

In this state, the welding head 112 is operated (i.e., a current for resistance welding is applied to the welding head 112), and the fixing portion 51 of the rupture member 50, which is in close contact with the bottom wall portion 11b, is welded to the bottom wall portion 11b. As a result, the outer peripheral surface of the fixing portion 51 is joined to the wall surface of the bottom wall portion 11b, and the rupture member 50 is fixed to the first casing 10.

Therefore, the through hole 11b1 serving as a gas inlet provided in the bottom wall portion 11b is closed by the rupture member 50, and the tank chamber S2 filled with compressed gas is sealed by the rupture member 50. As a result, the compressed gas is sealed in the tank chamber S2. After the above-mentioned welding is completed, the supply of gas from the gas supply source of the gas filling device and the holding of the rupture member 50 by the negative pressure source of the welding device are both released.

Next, as shown in Figures 5 and 11, in step ST17, the heat generating agent 60 is filled, and then in step ST18, the igniter assembly 30 is assembled to the first casing 10.

Specifically, as shown in FIG. 11, a predetermined amount of heat generating agent 60 is poured into the space inside the first peripheral wall portion 11a of the first case body 11, which has been detached from the head portion 110 of the compressed gas charging device 100, from the first open end 11a1 side of the first peripheral wall portion 11a, and then the holder 31 of the igniter assembly 30 is inserted and pressed into the first open end 11a1, and then the holder 31 is welded to the first case body 11, for example, by laser welding, thereby assembling the igniter assembly 30 to the first case body 11. In this way, the heat generating agent 60 is filled and the igniter assembly 30 is assembled to the first casing 10.

By going through the above steps ST11 to ST18, the manufacture of the hybrid gas generator 1A according to the present embodiment described above is completed.

In the manufacturing method of the hybrid gas generator according to the present embodiment described above, when the compressed gas is charged into the tank chamber S2, the through hole 11b1 provided in the bottom wall portion 11b of the first case body 11 is used as a gas inlet, and after the compressed gas is charged, the through hole 11b1 is closed by the rupture member 50. Therefore, by adopting this manufacturing method, it is not necessary to provide a structural portion in the housing that is used only for charging the compressed gas, and it is possible to simplify the configuration of the gas generator itself and facilitate the assembly work.

In addition, in this embodiment, during the manufacture of the hybrid gas generator 1A, the end face on the first open end 11a1 side of the first peripheral wall portion 11a of the first case body 11 is pressed against the head portion 110 of the compressed gas charging device 100, so the volume of the closed space described above can be significantly narrowed. Therefore, when drawing a vacuum, the degree of vacuum in the tank chamber S2 can be reduced to a predetermined degree of vacuum in a short time, and when filling with gas, the pressure in the tank chamber S2 can be increased to a predetermined high pressure state in a short time. Therefore, the time required for manufacturing can be shortened, which also leads to a reduction in manufacturing costs.

In addition, in this embodiment, since compressed gas can be injected into a housing using a compressed gas injection device 100 equipped with a small head unit 110 configured as described above, there is also the advantage that the manufacturing equipment can be significantly smaller than conventional compressed gas injection devices.

Furthermore, when gas is filled, heat is generated as the gas is compressed. However, as described above, in this embodiment, the volume of the closed space described above is significantly narrowed, so the variation in the amount of heat generated can be suppressed. Therefore, the variation in the amount of compressed gas filled between manufactured products can be suppressed, and hybrid gas generators that provide the desired gas output can be manufactured with a higher yield.

In addition, in this embodiment, during the manufacture of the hybrid gas generator 1A, the shape of the part of the housing that is pressed against the head portion 110 of the compressed gas injection device 100 (i.e., the end surface on the first open end 11a1 side of the first peripheral wall portion 11a of the first case body 11) is flat, so it is easier to ensure the airtightness of the closed space described above than when a gas injection port is provided on a curved peripheral wall of the housing (i.e., the first peripheral wall portion 11a of the first case body 11 or the second peripheral wall portion 21a of the second case body 21), and high-pressure gas can be injected more easily.

In addition, in this embodiment, when manufacturing the hybrid gas generator 1A, the through hole 11b1 provided in the bottom wall portion 11b of the first casing 10 after the second casing 20 is assembled is used as a gas inlet, so there is no need to manufacture the compressed gas filling portion that defines the tank chamber and the detonation portion that defines the ignition chamber in which the combustible agent is contained and has the igniter assembly assembled thereto as separate units and then combine them, making it possible to manufacture the hybrid gas generator extremely easily.

(First Modification)
Fig. 12 is a schematic diagram showing an assembly structure of a rupture member to a first casing in a hybrid gas generator according to a first modified example based on the above-mentioned embodiment 1. Here, (A) shows a state before assembly, and (B) shows a state after assembly. Below, the assembly structure of rupture member 50 to first casing 10 in hybrid gas generator 1A1 according to the first modified example will be described with reference to Fig. 12.

As shown in FIG. 12, the hybrid gas generator 1A1 according to the first modified example differs from the hybrid gas generator 1A according to the above-described first embodiment only in the shape of the rupture member 50.

Specifically, the rupture member 50 has a tapered, generally cylindrical fixed portion 51 whose outer diameter decreases from the ignition chamber S1 side toward the tank chamber S2 side, and a circular, thin-plate-like rupture portion 52 that closes the end of the fixed portion 51 on the tank chamber S2 side. The fixed portion 51 is further provided with a flange-like stopper portion 51b that extends radially outward. Here, the stopper portion 51b is located at the open end (i.e., the end on the ignition chamber S1 side) located opposite the axial end of the fixed portion 51 on which the rupture portion 52 is provided, and has an outer diameter larger than the inner diameter of the through hole 11b1 provided in the bottom wall portion 11b of the first case body 11.

In this first modified example, the rupture member 50 is fixed to the first case body 11 in a state where it is inserted into the through hole 11b1 provided in the bottom wall portion 11b of the first case body 11. More specifically, the rupture member 50 is inserted so that the outer peripheral surface of the fixing portion 51 abuts against the wall surface of the bottom wall portion 11b at the portion that defines the through hole 11b1, and resistance welding is performed in this state to fix the rupture member 50 to the first case body 11. As a result, the outer peripheral surface of the fixing portion 51 is joined to the wall surface of the bottom wall portion 11b.

Even with this configuration, it is possible to bring the outer peripheral surface of the fixing portion 51 into close contact with the above-mentioned wall surface of the bottom wall portion 11b, and the contact area can be made to a predetermined size. Therefore, by adopting this configuration, it is possible to reliably and stably fix the rupture member 50 to the bottom wall portion 11b.

As described above, a flange-shaped stopper portion 51b is provided on the open end side of the fixed portion 51 of the rupture member 50, so that when the rupture member 50 is inserted into the through hole 11b1, the stopper portion 51b abuts against the main surface of the bottom wall portion 11b on the ignition chamber S1 side. The abutment of the stopper portion 51b against the bottom wall portion 11b restricts the movement of the rupture member 50 toward the tank chamber S2 side.

Therefore, when the rupture member 50 has this configuration, the positioning of the rupture member 50 can be more reliably performed using the stopper portion 51b. Therefore, by adopting a configuration like that of this first modified example, when assembling the rupture member 50 to the first casing 10, the contact area between the outer circumferential surface of the fixing portion 51 and the wall surface of the bottom wall portion 11b at the portion that defines the through hole 11b1 can be more reliably maintained at a predetermined size, and the rupture member 50 can be more reliably and stably fixed to the bottom wall portion 11b.

(Second to Fourth Modifications)
Figures 13 to 15 are schematic diagrams showing the assembly structure of a rupture member to a first casing in hybrid gas generators according to second to fourth modified examples based on the above-mentioned embodiment 1, respectively. Here, in each figure, (A) shows the state before assembly, and (B) shows the state after assembly. Below, the assembly structure of rupture member 50 to first casing 10 in hybrid gas generators 1A2 to 1A4 according to the second to fourth modified examples will be described with reference to Figures 13 to 15.

As shown in Figures 13 to 15, the hybrid gas generators 1A2 to 1A4 according to the second to fourth modified examples differ only in the shape of the rupture member 50 when compared to the hybrid gas generator 1A according to the first embodiment described above.

As shown in FIG. 13, in the hybrid gas generator 1A2 according to the second modified example, the rupture member 50 has a tapered, generally cylindrical fixed portion 51 whose outer diameter decreases from the ignition chamber S1 side toward the tank chamber S2 side, and a circular thin plate-like rupture portion 52 that closes the end of the fixed portion 51 on the tank chamber S2 side, and of these, the circular thin plate-like rupture portion 52 has a curved shape that bulges toward the tank chamber S2 side.

As shown in FIG. 14, in the hybrid gas generator 1A3 according to the third modified example, the rupture member 50 has a tapered, generally cylindrical fixed portion 51 whose outer diameter decreases from the ignition chamber S1 side toward the tank chamber S2 side, and a circular thin plate-like rupture portion 52 that closes the end of the fixed portion 51 on the tank chamber S2 side, and of these, the circular thin plate-like rupture portion 52 has a curved shape that bulges out toward the side opposite the tank chamber S2 side (i.e., the ignition chamber S1 side).

As shown in FIG. 15, in the hybrid gas generator 1A4 according to the fourth modified example, the rupture member 50 has a tapered, generally cylindrical fixed portion 51 whose outer diameter decreases from the ignition chamber S1 side toward the tank chamber S2 side, and a circular, thin-plate rupture portion 52 that closes the end of the fixed portion 51 on the tank chamber S2 side, and the outer surface of the annular corner portion 53 that connects the fixed portion 51 and the rupture portion 52 is configured as a curved surface.

Even when the configurations of the second to fourth modified examples are adopted, it is possible to bring the outer peripheral surface of the fixing portion 51 into close contact with the above-mentioned wall surface of the bottom wall portion 11b, and the contact area can be made to a predetermined size. Therefore, by adopting this configuration, it is possible to reliably and stably fix the rupture member 50 to the bottom wall portion 11b.

(Fifth and Sixth Modifications)
Fig. 16 and Fig. 17 are schematic diagrams showing the assembly structure of a rupture member to a first casing in hybrid gas generators according to fifth and sixth modified examples based on the above-mentioned embodiment 1, respectively. Here, in each figure, (A) shows the state before assembly, and (B) shows the state after assembly. Below, with reference to Fig. 16 and Fig. 17, the assembly structure of rupture member 50 to first casing 10 in hybrid gas generators 1A5, 1A6 according to the fifth and sixth modified examples will be described.

As shown in Figures 16 and 17, when compared with the hybrid gas generator 1A according to the first embodiment described above, the hybrid gas generators 1A5, 1A6 according to the fifth and sixth modified examples only differ in the shape of the through hole 11b1 provided in the bottom wall portion 11b of the first case body 11 and the shape of the rupture member 50.

As shown in FIG. 16, in the hybrid gas generator 1A5 according to the fifth modified example, the through hole 11b1 provided in the bottom wall portion 11b of the first case body 11 has a cylindrical shape with a constant inner diameter from the ignition chamber S1 side to the tank chamber S2 side. On the other hand, the rupture member 50 has a cylindrical fixing portion 51 with an outer diameter that is constant from the ignition chamber S1 side to the tank chamber S2 side corresponding to the inner diameter of the through hole 11b1, and a circular thin plate-like rupture portion 52 that closes the end of the fixing portion 51 on the tank chamber S2 side.

As shown in FIG. 17, in the hybrid gas generator 1A6 according to the sixth modified example, the through hole 11b1 provided in the bottom wall portion 11b of the first case body 11 has a cylindrical shape with a constant inner diameter from the ignition chamber S1 side to the tank chamber S2 side. On the other hand, the rupture member 50 has a cylindrical fixed portion 51 with an outer diameter that is constant from the ignition chamber S1 side to the tank chamber S2 side corresponding to the inner diameter of the through hole 11b1, and a circular thin plate-like rupture portion 52 that closes the end of the fixed portion 51 on the ignition chamber S1 side.

In other words, the hybrid gas generator 1A5 according to the fifth modified example and the hybrid gas generator 1A6 according to the sixth modified example have a common configuration except that the rupture member 50 inserted into the through hole 11b1 is oriented in the opposite directions.

Even when the configurations of the fifth and sixth modified examples are adopted, it is possible to bring the outer peripheral surface of the fixing portion 51 into close contact with the above-mentioned wall surface of the bottom wall portion 11b, and the contact area can be made to a predetermined size. Therefore, by adopting this configuration, it is possible to reliably and stably fix the rupture member 50 to the bottom wall portion 11b.

(Embodiment 2)
Fig. 18 is a schematic cross-sectional view of a stored-type gas generator according to embodiment 2. Fig. 19 is an enlarged view of the vicinity of the igniter assembly and ignition chamber of the stored-type gas generator shown in Fig. 18 and the vicinity of the closed portion of the second casing. First, with reference to Figs. 18 and 19, the configuration of stored-type gas generator 1B according to the present embodiment will be described. Note that stored-type gas generator 1B according to the present embodiment has a so-called reverse flow structure.

As shown in FIG. 18, the stored-type gas generator 1B according to this embodiment has a similar configuration to the hybrid-type gas generator 1A according to the above-mentioned embodiment 1, and when compared to the hybrid-type gas generator 1A, the difference lies mainly in the configuration of the housing of the portion that defines the tank chamber S2, and in addition to this, the configuration differs in that it does not have a nozzle assembly 40 and a heat generating agent 60 (both see FIG. 1, etc.), and in that the positions at which the multiple gas outlets are formed and the configuration near the multiple gas outlets are different.

Specifically, the stored-type gas generator 1B has an overall long, roughly cylindrical shape, and mainly comprises a first casing 10, a second casing 20, an igniter assembly 30, a rupture member 50, and compressed gas (not shown in the figure).

The housing of the stored-type gas generator 1B is composed of a holder 31 included in the igniter assembly 30, a first casing 10, and a second casing 20. Of these, the first casing 10 is composed of a first case body 11, and the second casing 20 is composed of a second case body 21.

The space inside the housing is divided into an ignition chamber S1, which is mainly defined by the holder 31 and the first case body 11, and a tank chamber S2, which is mainly defined by the first case body 11 and the second case body 21. The tank chamber S2 is filled with compressed gas, as in the hybrid gas generator 1A according to the first embodiment described above, whereas the ignition chamber S1 is not filled with the heat generating agent 60, unlike the hybrid gas generator 1A.

As shown in Figures 18 and 19, the first case body 11 and the igniter assembly 30 have the same configuration as those in the hybrid gas generator 1A according to the first embodiment described above. On the other hand, the second case body 21 is made of a single cylindrical member with a bottom including a second peripheral wall portion 21a and a closing portion 21b. The second peripheral wall portion 21a has a cylindrical shape, and one axial end thereof is configured as a second open end 21a1. The closing portion 21b has a curved plate shape, and closes the other axial end of the second peripheral wall portion 21a.

The first open end 11a1 of the first case body 11 is closed by the holder 31 (more precisely, the igniter assembly 30), and the second open end 21a1 of the second case body 21 is closed by the bottom wall portion 11b of the first case body 11. A through hole 11b1 is provided in the bottom wall portion 11b of the first case body 11 so as to communicate with both the ignition chamber S1 and the tank chamber S2.

A rupture member 50 consisting of a single, bottomed, substantially cylindrical member including a substantially cylindrical fixing portion 51 and a circular, thin plate-like rupture portion 52 is inserted into the through hole 11b1, and in this state, the rupture member 50 is fixed to the first case body 11. The configuration of the rupture member 50 and the assembly structure of the rupture member 50 to the first case body 11 are the same as those in the hybrid gas generator 1A according to the first embodiment described above.

The first peripheral wall portion 11a of the first case body 11 is provided with multiple gas outlets 11c facing the ignition chamber S1. The multiple gas outlets 11c are used to eject gas to the outside when the stored-type gas generator 1B is in operation.

A metal sealing tape 12 is attached to the inner circumferential surface of the first peripheral wall portion 11a of the first case body 11 so as to close the multiple gas outlets 11c. This sealing tape 12 can be preferably made of aluminum foil with an adhesive applied to one side, and the sealing tape 12 ensures the airtightness of the ignition chamber S1.

Next, the operation of the stored-type gas generator 1B according to this embodiment having the above-mentioned configuration will be described with reference to the aforementioned Figures 18 and 19.

First, the igniter 32 is activated by receiving electricity from the control unit. When the igniter 32 is activated, the ignition charge filled in the ignition section 32a is heated by a resistor and ignited, and the ignition charge burns, causing the ignition section 32a to explode.

The combustion of the ignition charge causes the pressure and temperature in the ignition chamber S1 to rise, which causes the rupture portion 52 of the rupture member 50 to rupture. As the rupture portion 52 ruptures, the ignition chamber S1 and the tank chamber S2 are connected via the through hole 11b1 provided in the bottom wall portion 11b of the first case body 11. At this time, the fixed portion 51 of the rupture member 50 remains without being burned, so more precisely, the ignition chamber S1 and the tank chamber S2 are connected via the hollow portion 51a located inside the fixed portion 51.

Next, as the ignition chamber S1 and the tank chamber S2 are connected via the through hole 11b1, the compressed gas flows into the ignition chamber S1 via the through hole 11b1 and is then ejected to the outside from the multiple gas ejection ports 11c.

The gas ejected from the multiple gas ejection ports 11c to the outside of the stored-type gas generator 1B is introduced into the airbag provided adjacent to the stored-type gas generator 1B, causing the airbag to inflate and deploy.

By using the stored-type gas generator 1B according to the present embodiment described above, it is possible to obtain the same effects as in the case of using the hybrid-type gas generator 1A according to the first embodiment described above.

(Related form 1)
Fig. 20 is a schematic cross-sectional view of a hybrid gas generator according to related form 1. Fig. 21 is an enlarged view of the vicinity of the igniter assembly and ignition chamber of the hybrid gas generator shown in Fig. 20. Also, Fig. 22 is a schematic view showing the assembly structure of the sealing portion assembly to the first casing in the hybrid gas generator shown in Fig. 20, (A) and (B) showing the state before and after assembly, respectively. First, with reference to Figs. 20 to 22, the configuration of a hybrid gas generator 1C according to this related form and the assembly structure of a sealing portion assembly 70 to first casing 10 will be described. Note that the hybrid gas generator 1C according to this related form has a so-called blow-down structure.

As shown in FIG. 20, the hybrid gas generator 1C according to this related embodiment has a configuration similar to the hybrid gas generator 1A according to the above-described first embodiment, and differs from the hybrid gas generator 1A only in the configuration of the member that closes the through hole 11b1 provided in the bottom wall portion 11b of the first case body 11.

That is, in the hybrid gas generator 1A according to the first embodiment described above, the through hole 11b1 provided in the bottom wall portion 11b of the first case body 11 is closed by a bottomed, generally cylindrical rupture member 50 inserted into the through hole 11b1 (see FIG. 1, etc.), but in the hybrid gas generator 1C according to this related embodiment, this is closed by a sealing portion assembly 70.

As shown in Figures 20 to 22, the sealing assembly 70 has a plug 71 and a rupture disk 72 as a rupture member. The sealing assembly 70 is configured as a pre-integrated part by joining the plug 71 and the rupture disk 72.

The plug 71 has a hollow, generally cylindrical shape. The plug 71 has a communication hole 71a extending along the axial direction, which reaches each of a pair of axial end faces of the plug 71. On the other hand, the rupture disc 72 has a circular, thin plate shape.

A ring-shaped protrusion 71b is provided on the axial end face of the plug 71 on the tank chamber S2 side so as to surround the communication hole 71a. This ring-shaped protrusion 71b is a portion for assembling the rupture disc 72 to the plug 71 by resistance welding. By providing this ring-shaped protrusion 71b, the contact area between the plug 71 and the rupture disc 72 becomes a predetermined size, so that the rupture disc 72 can be reliably and stably fixed to the plug 71 during resistance welding.

By joining the rupture disc 72 to the plug body 71 in this manner, the communication hole 71a provided in the plug body 71 is closed by the rupture disc 72 at the axial end face of the plug body 71 on the tank chamber S2 side.

The method of fixing the rupture disc 72 to the plug 71 is not limited to the resistance welding method described above, and other fixing methods may be used.

The rupture disc 72 can be ruptured when the igniter 32 is activated, and is preferably made of a metal member.

Here, since a portion of the rupture disc 72 is exposed to the compressed gas for a long period of time, it is preferable that the rupture disc 72 is made of a nickel alloy member formed from a thin metal plate such as SUS316 (JIS standard symbol) or Inconel (registered trademark) from the viewpoint of corrosion resistance. For example, a metal thin plate (e.g., about 200 μm thick) having heat resistance and corrosion resistance is preferably used as the rupture disc 72, and a thin plate made of stainless steel or Inconel alloy (Inconel 625) having the composition ratio of Ni: 10 [wt %], Cr: 23 [wt %], Mn: 6 [wt %], Mo: 2 [wt %], C: 0.01 [wt %], N: 0.5 [wt %], or other components is particularly preferably used.

The plug 71 functions as a pressure bulkhead together with the bottom wall 11b of the first case body 11, and is made of a metal member such as stainless steel or steel. Here, since a portion of the plug 71 will be exposed to compressed gas for a long period of time, it is preferable that the plug be made of a steel material to which chromium, manganese, molybdenum, niobium, nickel, etc. are added so that the plug has excellent corrosion resistance.

The plug body 71 is fixed to the first case body 11 in a state where it is inserted into the through hole 11b1 provided in the bottom wall portion 11b of the first case body 11. More specifically, as shown in FIG. 22, the plug body 71 is inserted so that its outer circumferential surface abuts against the wall surface of the bottom wall portion 11b in the portion that defines the through hole 11b1, and resistance welding is performed in this state to fix it to the first case body 11. As a result, the outer circumferential surface of the plug body 71 is joined to the wall surface of the bottom wall portion 11b.

The plug body 71 is assembled by being inserted into the through hole 11b1 from the first open end 11a1 side of the first peripheral wall portion 11a as described below, so the plug body 71 has a shape that allows it to be inserted into the through hole 11b1 from the first open end 11a1 side (i.e., from the ignition chamber S1 side).

Specifically, in this related embodiment, the through hole 11b1 provided in the bottom wall portion 11b has a tapered shape in which the inner diameter becomes smaller from the ignition chamber S1 side toward the tank chamber S2 side, and the plug body 71 has a tapered shape in which the outer diameter becomes smaller from the ignition chamber S1 side toward the tank chamber S2 side corresponding to the above-mentioned tapered shape of the through hole 11b1. In addition, the rupture disk 72 has an outer diameter smaller than the inner diameter of the through hole 11b1.

By tapering the through hole 11b1 and the plug 71 in this way, when assembling the sealing assembly 70 to the bottom wall 11b, it is possible to position and arrange the plug 71 with high precision relative to the bottom wall 11b, and it is possible to bring the outer peripheral surface of the plug 71 into close contact with the above-mentioned wall surface of the bottom wall 11b, resulting in a predetermined contact area. Therefore, by performing resistance welding in this state, it is possible to reliably and stably fix the sealing assembly 70 to the bottom wall 11b.

Next, the operation of the hybrid gas generator 1C according to this related embodiment having the above-mentioned configuration will be described with reference to the aforementioned Figures 20 and 21.

First, the igniter 32 is activated by receiving electricity from the control unit described above. When the igniter 32 is activated, the ignition charge filled in the ignition section 32a is heated by a resistor and ignited, and the ignition charge burns, causing the ignition section 32a to explode. As a result, the heat generating agent 60 contained in the ignition chamber S1 is ignited by the igniter 32 and burns.

The combustion of the ignition charge and heat generating agent 60 increases the pressure and temperature in the ignition chamber S1, which causes the rupture disc 72 to burst. As the rupture disc 72 bursts, the ignition chamber S1 and the tank chamber S2 are connected via the communication hole 71a provided in the plug 71.

Next, as the ignition chamber S1 and the tank chamber S2 communicate with each other, the pressure and temperature in the tank chamber S2 also rise, causing the rupture disc 42 to rupture in a portion facing the flow path 41c. As the rupture disc 42 ruptures, the tank chamber S2 and the multiple gas outlets 41d communicate with each other via the flow path 41c (see FIG. 3).

As a result, the compressed gas contained in the tank chamber S2 flows through the flow path 41c to the multiple gas outlets 41d, and is then ejected from the multiple gas outlets 41d to the outside.

The gas ejected from the multiple gas ejection ports 41d to the outside of the hybrid gas generator 1C is introduced into an airbag provided adjacent to the hybrid gas generator 1C, causing the airbag to inflate and deploy.

By configuring the hybrid gas generator 1C according to the related embodiment described above, it is possible to reduce the weight while ensuring the pressure resistance of the housing. That is, as explained in the above-mentioned embodiment 1, also in the hybrid gas generator 1C according to the related embodiment, of the part constituting the peripheral wall of the housing and the part constituting the partition part, the peripheral wall of the part defining the ignition chamber S1 and the partition part are configured from the first case body 11 made of a single cylindrical member with a bottom, and the remaining peripheral wall of the part defining the tank chamber S2 is configured from the second case body 21.

Therefore, by adopting this configuration, it is easy to make the thickness of the first peripheral wall portion 11a and the bottom wall portion 11b of the first case body 11 relatively thick while making the thickness of the second peripheral wall portion 21a of the second case body 21 relatively thin, thereby realizing a lightweight housing while suppressing an increase in the number of parts.

In addition, in the hybrid gas generator 1C according to this related embodiment, among the housing walls that define the tank chamber S2 in which compressed gas is sealed, no opening is provided in the second peripheral wall portion 21a of the second case body 21, and no opening is provided in the bottom wall portion 11b of the first case body 11 other than the through hole 11b1 that is closed by the sealing portion assembly 70.

This characteristic configuration results from the fact that the hybrid gas generator 1C according to this related embodiment is manufactured according to the manufacturing method for the hybrid gas generator according to this related embodiment described below. In summary, when the compressed gas is injected into the tank chamber S2, the through hole 11b1 provided in the bottom wall portion 11b of the first case body 11 is used as a gas injection port, and after the compressed gas is injected, the through hole 11b1 is closed by the sealing portion assembly 70.

The above points will be explained in more detail below while specifically explaining the manufacturing method of the hybrid gas generator according to this related embodiment. Figure 23 is a flow diagram showing the manufacturing method of the hybrid gas generator according to this related embodiment, and Figures 24 and 25 are schematic cross-sectional views of some of the steps shown in Figure 23.

As shown in FIG. 23, when manufacturing a hybrid gas generator 1C according to this related embodiment, first, in step ST21, the igniter assembly 30, the nozzle assembly 40, and the sealing assembly 70 are each manufactured. Of these, the manufacture of the igniter assembly 30 and the nozzle assembly 40 is similar to step ST11 described in the above-mentioned first embodiment. On the other hand, the manufacture of the sealing assembly 70 is performed by joining the rupture disk 72 to the plug 71 by resistance welding, whereby the sealing assembly 70 is manufactured as an integrated part.

Next, in step ST22, the second casing 20 is assembled and attached to the first casing 10. This step ST22 is similar to step ST12 described in the first embodiment above.

23 and 24, in step ST23, the first casing 10 is positioned relative to the head portion 110 of the compressed gas injection device 100. This step ST23 is basically the same as step ST13 described in the above-mentioned embodiment 1, but as shown in FIG. 24, the welding head 112 of the compressed gas injection device 100 holds the sealing portion assembly 70 in advance.

Therefore, when the end face of the first open end 11a1 of the first peripheral wall portion 11a of the first case body 11 is abutted against the main surface 111b of the gas filling head 111, and the first casing 10 is positioned relative to the head portion 110 of the compressed gas filling device 100, the sealing portion assembly 70 is held by the welding head 112 inside the closed space formed by the first case body 11 and the gas filling head 111.

Next, as shown in FIG. 23, evacuation and gas filling are performed in sequence in steps ST24 and ST25. These steps ST24 and ST25 are similar to steps ST14 and ST15 described in the first embodiment above.

Next, as shown in Figures 23 and 25, in step ST26, the sealing assembly 70 is assembled to the first casing 10.

Specifically, as shown in FIG. 25, after the tank chamber S2 is filled with compressed gas in step ST25, the sealing assembly 70, which has been held by the welding head 112 inside the closed space described above, is moved by driving the welding head 112, and the sealing assembly 70 is inserted into the through hole 11b1 serving as a gas inlet. At that time, the sealing assembly 70 is positioned so that the outer peripheral surface of the plug 71 is in close contact with the wall surface of the bottom wall portion 11b that defines the through hole 11b1.

In this state, the welding head 112 is operated (i.e., a current for resistance welding is applied to the welding head 112), and the plug 71, which is in close contact with the bottom wall 11b, is welded to the bottom wall 11b. As a result, the outer peripheral surface of the plug 71 is joined to the above-mentioned wall surface of the bottom wall 11b, and the sealing assembly 70 is fixed to the first casing 10.

Therefore, the through hole 11b1 serving as a gas inlet provided in the bottom wall portion 11b is closed by the sealing assembly 70, and the tank chamber S2 filled with compressed gas is sealed by the sealing assembly 70. This causes the compressed gas to be sealed in the tank chamber S2. As described above, when the hybrid gas generator 1C is in operation, the rupture disc 72 ruptures, so that the ignition chamber S1 and the tank chamber S2 communicate with each other via the communication hole 71a provided in the plug 71. Therefore, in the above-mentioned step ST26, it can be said that the tank chamber S2 filled with compressed gas is sealed by the rupture disc 72 of the sealing assembly 70.

Next, as shown in FIG. 23, in step ST27, the heat generating agent 60 is filled, and then in step ST28, the igniter assembly 30 is assembled into the first casing 10. These steps ST27 and ST28 are similar to steps ST17 and ST18 described in the first embodiment above.

By going through the above steps ST21 to ST28, the manufacture of the hybrid gas generator 1C according to the above-mentioned related embodiment is completed.

By adopting the manufacturing method for the hybrid gas generator according to the present related embodiment described above, it is possible to obtain the same effects as when adopting the manufacturing method for the hybrid gas generator according to the above-mentioned embodiment 1.

(Seventh Modification)
Fig. 26 is a schematic diagram showing the assembly structure of a sealing portion assembly to a first casing in a hybrid gas generator related to a seventh modified example based on the above-mentioned related form 1. Here, (A) shows the state before assembly, and (B) shows the state after assembly. Below, the assembly structure of sealing portion assembly 70 to first casing 10 in hybrid gas generator 1C1 related to the seventh modified example will be described with reference to Fig. 26.

As shown in FIG. 26, the hybrid gas generator 1C1 of the seventh modified example differs from the hybrid gas generator 1C of the related form 1 described above only in the shape of the plug 71 of the sealing assembly 70.

Specifically, the sealing assembly 70 has a taper-shaped plug 71 whose outer diameter decreases from the ignition chamber S1 side toward the tank chamber S2 side, and this plug 71 is further provided with a flange-shaped stopper portion 71c that extends radially outward. Here, the stopper portion 71c is located at the axial end portion (i.e., the end portion on the ignition chamber S1 side) located opposite the axial end portion on the side where the rupture disc 72 of the plug 71 is provided, and has an outer diameter larger than the through hole 11b1 provided in the bottom wall portion 11b of the first case body 11.

In this way, by providing a flange-shaped stopper portion 71c on the ignition chamber S1 side of the plug body 71, when the sealing assembly 70 is inserted into the through hole 11b1, the stopper portion 71c abuts against the main surface of the bottom wall portion 11b on the ignition chamber S1 side. This abutment of the stopper portion 71c against the bottom wall portion 11b restricts the movement of the sealing assembly 70 toward the tank chamber S2 side.

Therefore, when the sealing assembly 70 is configured in this way, the positioning of the sealing assembly 70 can be more reliably performed using the stopper portion 71c. Therefore, by adopting a configuration like that of the seventh modified example, when assembling the sealing assembly 70 to the first casing 10, the contact area between the outer circumferential surface of the plug 71 and the wall surface of the bottom wall portion 11b that defines the through hole 11b1 can be more reliably maintained at a predetermined size, and the sealing assembly 70 can be more reliably and stably fixed to the bottom wall portion 11b.

(Eighth Modification)
Fig. 27 is a schematic diagram showing the assembly structure of a sealing portion assembly to a first casing in a hybrid gas generator relating to an eighth modified example based on the above-mentioned related form 1. Here, (A) shows the state before assembly, and (B) shows the state after assembly. Below, the assembly structure of sealing portion assembly 70 to first casing 10 in hybrid gas generator 1C2 relating to the eighth modified example will be described with reference to Fig. 27.

As shown in FIG. 28, the hybrid gas generator 1C2 of the eighth modified example differs from the hybrid gas generator 1C of the related form 1 described above only in the shape of the through hole 11b1 provided in the bottom wall portion 11b of the first case body 11 and the shape of the plug 71 of the sealing portion assembly 70.

Specifically, the through hole 11b1 provided in the bottom wall portion 11b of the first case body 11 has a cylindrical shape with a constant inner diameter from the ignition chamber S1 side to the tank chamber S2 side. On the other hand, the plug body 71 of the sealing portion assembly 70 has an outer diameter that is constant from the ignition chamber S1 side to the tank chamber S2 side corresponding to the inner diameter of the through hole 11b1.

Even with this configuration, it is possible to bring the outer peripheral surface of the plug 71 into close contact with the above-mentioned wall surface of the bottom wall 11b, and the contact area can be made a predetermined size. Therefore, by adopting this configuration, it is possible to reliably and stably fix the sealing assembly 70 to the bottom wall 11b.

(Related form 2)
Fig. 28 is a schematic cross-sectional view of a stored-type gas generator according to related embodiment 2. Fig. 29 is an enlarged view of the vicinity of the igniter assembly and the ignition chamber of the stored-type gas generator shown in Fig. 28 and the vicinity of the closed portion of the second casing. First, with reference to Figs. 28 and 29, the configuration of a stored-type gas generator 1D according to this related embodiment will be described. Note that stored-type gas generator 1D according to this related embodiment has a so-called reverse flow structure.

As shown in FIG. 28, the stored-type gas generator 1D according to this related embodiment has a similar configuration to the hybrid-type gas generator 1C according to related embodiment 1 described above, and when compared to the hybrid-type gas generator 1C, the difference lies mainly in the configuration of the housing of the portion that defines the tank chamber S2, and in addition to this, the configuration differs in that it does not have a nozzle assembly 40 and a heat generating agent 60 (both see FIG. 20, etc.), and in that the positions at which the multiple gas outlets are formed and the configuration near the multiple gas outlets are different.

Specifically, the stored-type gas generator 1D has an overall long, roughly cylindrical outer shape, and mainly comprises a first casing 10, a second casing 20, an igniter assembly 30, a sealing assembly 70, and compressed gas (not shown in the figure).

The housing of the stored-type gas generator 1D is composed of a holder 31 included in the igniter assembly 30, a first casing 10, and a second casing 20. Of these, the first casing 10 is composed of a first case body 11, and the second casing 20 is composed of a second case body 21.

The space inside the housing is divided into an ignition chamber S1, which is mainly defined by the holder 31 and the first case body 11, and a tank chamber S2, which is mainly defined by the first case body 11 and the second case body 21. The tank chamber S2 is filled with compressed gas, as in the hybrid gas generator 1C according to the above-mentioned related embodiment 1, but the ignition chamber S1 is not filled with the heat generating agent 60, unlike the hybrid gas generator 1C.

As shown in Figures 28 and 29, the first case body 11 and the igniter assembly 30 have the same configuration as those in the hybrid gas generator 1C according to the above-mentioned related form 1. On the other hand, the second case body 21 is made of a single cylindrical member with a bottom including the second peripheral wall portion 21a and the closing portion 21b. The second peripheral wall portion 21a has a cylindrical shape, and one axial end thereof is configured as the second open end 21a1. The closing portion 21b has a curved plate shape, and closes the other axial end of the second peripheral wall portion 21a.

The first open end 11a1 of the first case body 11 is closed by the holder 31 (more precisely, the igniter assembly 30), and the second open end 21a1 of the second case body 21 is closed by the bottom wall portion 11b of the first case body 11. A through hole 11b1 is provided in the bottom wall portion 11b of the first case body 11 so as to communicate with both the ignition chamber S1 and the tank chamber S2.

A sealing assembly 70 having a hollow, generally cylindrical plug 71 and a circular, thin-plate rupture disk 72 is inserted into the through hole 11b1, and in this state, the sealing assembly 70 is fixed to the first case body 11. The configuration of the sealing assembly 70 and the assembly structure of the sealing assembly 70 to the first case body 11 are the same as those in the hybrid gas generator 1C according to the related embodiment 1 described above.

The first peripheral wall portion 11a of the first case body 11 is provided with multiple gas outlets 11c facing the ignition chamber S1. The multiple gas outlets 11c are used to eject gas to the outside when the stored-type gas generator 1D is in operation.

A metal sealing tape 12 is attached to the inner circumferential surface of the first peripheral wall portion 11a of the first case body 11 so as to close the multiple gas outlets 11c. This sealing tape 12 can be preferably made of aluminum foil with an adhesive applied to one side, and the sealing tape 12 ensures the airtightness of the ignition chamber S1.

Next, the operation of the stored-type gas generator 1D according to this related embodiment having the above-mentioned configuration will be described with reference to the aforementioned Figures 28 and 29.

First, the igniter 32 is activated by receiving electricity from the control unit. When the igniter 32 is activated, the ignition charge filled in the ignition section 32a is heated by a resistor and ignited, and the ignition charge burns, causing the ignition section 32a to explode.

The combustion of this ignition charge increases the pressure and temperature in the ignition chamber S1, which causes the rupture disc 72 to burst. As the rupture disc 72 bursts, the ignition chamber S1 and the tank chamber S2 are connected via the communication hole 71a provided in the plug 71.

Next, as the ignition chamber S1 and the tank chamber S2 are connected via the through hole 11b1, the compressed gas flows into the ignition chamber S1 via the through hole 11b1 and is then ejected to the outside from the multiple gas ejection ports 11c.

The gas ejected from the multiple gas ejection ports 11c to the outside of the stored-type gas generator 1D is introduced into the airbag provided adjacent to the stored-type gas generator 1D, causing the airbag to inflate and deploy.

By using the stored-type gas generator 1D according to the related embodiment described above, it is possible to obtain the same effects as in the case of using the hybrid-type gas generator 1C according to the related embodiment 1 described above.

(Summary of related forms 1 and 2)
The characteristic configurations of the hybrid-type gas generators and the stored-type gas generators according to the above-mentioned related forms 1 and 2 and their modified examples can be summarized as follows.

A gas generator according to a related embodiment includes an igniter and a housing. The housing has an ignition chamber facing the igniter and a tank chamber in which compressed gas is sealed, and is provided with a gas outlet that opens during operation. The housing has a holder to which the igniter is assembled, a first casing that defines the ignition chamber together with the holder, and a second casing that defines the tank chamber together with the first casing. The first casing has a first case body made of a single cylindrical member with a bottom, including a cylindrical first peripheral wall portion having one axial end configured as a first open end and a bottom wall portion that closes the other axial end of the first peripheral wall portion. The second casing has a second case body including at least a cylindrical second peripheral wall portion having one axial end configured as a second open end. The first open end is closed by the holder, and the second open end is closed by the bottom wall portion. The bottom wall portion is provided with a through hole that communicates with the ignition chamber and the tank chamber, and a plug that closes the through hole. The plug is provided with a communication hole for communicating the ignition chamber and the tank chamber, and a rupturable member that can be ruptured due to the activation of the igniter is provided in the plug to close the communication hole. The plug is inserted into the through hole and fixed by welding its outer circumferential surface to the wall surface of the bottom wall portion that defines the through hole.

In the gas generator according to the above-mentioned related embodiment, it is preferable that the plug body with the rupture member provided has a shape that allows it to be inserted into the through hole from the ignition chamber side.

In the gas generator according to the above-mentioned related embodiment, the through hole may have a tapered shape in which the inner diameter decreases from the ignition chamber side toward the tank chamber side, and in that case, the plug body may have a tapered shape in which the outer diameter decreases from the ignition chamber side toward the tank chamber side in correspondence with the tapered shape of the through hole.

In the gas generator according to the above-mentioned related embodiment, the plug may be provided with a stopper portion that abuts against the main surface of the bottom wall portion on the ignition chamber side to prevent the plug from moving toward the tank chamber side.

In the gas generator according to the above-mentioned related embodiment, it is preferable that the rupture member is fixed by welding to the part of the plug on the side facing the tank chamber.

In the gas generator according to the above-mentioned related embodiment, the ignition chamber may be filled with a heat generating agent that generates high-temperature heat when burned.

In the gas generator according to the above-mentioned related embodiment, the second case body may be configured as a cylindrical member in which the other axial end of the second peripheral wall portion is configured as a third open end, and in that case, the second casing may further have a nozzle body that closes the third open end and in which the gas outlet is provided.

In the gas generator according to the above-mentioned related embodiment, the second case body may be formed of a single cylindrical member with a bottom including a closing portion that closes the other axial end of the second peripheral wall portion, and in that case, the gas outlet may be provided in the first peripheral wall portion.

(Other forms, etc.)
In the above-mentioned first and second embodiments and related forms 1 and 2 of the present invention and their modified examples, the rupture member and sealing portion assembly that are attached to the bottom wall portion of the first case body as a partition portion are each provided so that a portion of them protrudes toward the tank chamber side. However, these may be inserted into the through hole so as to be flush with the bottom wall portion of the first case body, or they may be recessed from the opening surface of the through hole so as to be located inside the through hole.

In addition, in the above-mentioned embodiments 1 and 2 and related embodiments 1 and 2 of the present invention and their modified examples, the case where the vent passage provided in the gas filling head of the compressed gas charging device is configured to be selectively and switchably connected to the gas supply source and the negative pressure source has been described as an example, but it is also possible to provide the gas filling head with vent passages that are independently connected to the gas supply source and the negative pressure source, and to configure the gas supply source and the negative pressure source to be driven at different times.

Furthermore, the characteristic configurations of the above-mentioned embodiments 1 and 2 of the present invention and related embodiments 1 and 2, as well as their modified examples, can be combined with each other without departing from the spirit of the present invention.

Furthermore, in the above-mentioned first and second embodiments and related embodiments 1 and 2 of the present invention and their modified examples, the present invention has been described as being applied to a cylindrical gas generator incorporated in a side airbag device, but the application of the present invention is not limited to this, and it can also be applied to cylindrical gas generators incorporated in curtain airbag devices, knee airbag devices, seat cushion airbag devices, etc., and so-called T-shaped gas generators that have an elongated outer shape similar to a cylindrical gas generator.

As such, the above-described embodiments and related embodiments and their variations disclosed herein are illustrative in all respects and are not restrictive. The technical scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope equivalent to those described in the claims.

1A, 1A1 to 1A6, 1C, 1C1, 1C2 Hybrid type gas generator, 1B, 1D Stored type gas generator, 10 First casing, 11 First case body, 11a First peripheral wall portion, 11a1 First open end, 11b Bottom wall portion, 11b1 Through hole, 11c Gas outlet, 12 Sealing tape, 20 Second casing, 21 Second case body, 21a Second peripheral wall portion, 21a1 Second open end, 21a2 Third open end, 21b Closure portion, 30 Igniter assembly, 31 Holder, 31a Through portion, 32 Igniter, 32a Ignition portion, 32b Terminal pin, 33 Resin molded portion, 33a Recess, 40 Nozzle assembly, 41 Nozzle body, 41a Base portion, 41b Nozzle portion, 41c Flow path portion, 41d Gas outlet, 42 rupture disc, 50 rupture member, 51 fixing part, 51a hollow part, 51b stopper part, 52 rupture part, 53 corner part, 60 heat generating agent, 70 sealing part assembly, 71 plug body, 71a communication hole, 71b annular protrusion, 71c stopper part, 72 rupture disc, 100 compressed gas injection device, 110 head part, 111 gas filling head, 111a ventilation path, 111a1 gas outlet, 111b main surface, 112 welding head, 112a suction path, 112b main surface, S1 ignition chamber, S2 tank chamber.

Claims (4)

An igniter,
a housing having an ignition chamber facing the igniter and a tank chamber in which compressed gas is sealed, and a gas outlet that opens during operation;
the housing includes a holder to which the igniter is attached, a first casing that defines the ignition chamber together with the holder, and a second casing that defines the tank chamber together with the first casing,
the first casing has a first case body made of a single cylindrical member having a bottom including a first peripheral wall portion having an axial end configured as a first open end and a bottom wall portion closing the other axial end of the first peripheral wall portion,
the second casing has a second case body including at least a cylindrical second peripheral wall portion having one end in an axial direction configured as a second open end,
the first open end is closed by the holder;
the second open end is closed by the bottom wall portion,
The bottom wall portion is provided with a through hole communicating with the ignition chamber and the tank chamber,
a rupturable member that can be ruptured due to activation of the igniter is provided on the bottom wall portion so as to close the through hole;
the rupture member is composed of a single bottomed tubular member including a tubular fixing part that is inserted into the through hole and fixed by welding its outer circumferential surface to a wall surface of the bottom wall part of a portion that defines the through hole, and a plate-shaped rupture part that closes one axial end of the fixing part ,
The rupturable member has a shape that allows it to be inserted into the through hole from the ignition chamber side,
The through hole has a tapered shape in which an inner diameter becomes smaller from the ignition chamber side toward the tank chamber side,
The fixing portion has a tapered shape in which an outer diameter becomes smaller from the ignition chamber side toward the tank chamber side in correspondence with the tapered shape of the through hole. 2. The gas generator according to claim 1 , wherein a stopper portion is provided on the rupturable member for restricting the rupturable member from moving toward the tank chamber by abutting against a main surface of the bottom wall portion on the ignition chamber side. 3. The gas generator according to claim 1 , wherein the rupture portion is located at an end of the fixing portion on the tank chamber side. 4. The gas generator according to claim 3 , wherein an outer surface of an annular corner portion connecting said fixed portion and said rupture portion is configured as a curved surface.

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