Igniter assembly and gas generation device

Abstract

Provided is a feature for ensuring the airtightness of a combustion chamber. This igniter assembly comprises: an ignition device having an igniter provided with a firing part that hermetically houses an ignition charge and a conductive part that supplies a firing current to fire the ignition charge, a tubular igniter-holding part that surrounds and holds the igniter, and a resin-made fixing member that is interposed between the igniter and the igniter-holding part and that fixes the igniter to the igniter-holding part; a bottomed tubular case that houses a first gas-generating agent and the firing part of the ignitor on one axial side of the igniter-holding part; and a moisture-impermeable dividing wall that divides the interior of the case into a space in which the igniter and the fixing member are disposed and a space in which the first gas-generating agent is housed. The dividing wall is fixed in contact with the case, and the entire periphery of the dividing wall is welded to at least one of the igniter-holding part and the case.

Description

Igniter assembly and gas generator

[0001] The present invention relates to an igniter assembly and a gas generator.

[0002] Conventionally, an igniter assembly has been proposed that includes a cup that houses a gas generating agent and has one axial end that is open, and a holder that is coaxially assembled to the cup so that the open end of the cup is closed (see, for example, Patent Document 1). In this igniter assembly, an annular weld is provided at the open end, and the cup is fixed to the holder.

[0003] Also, an initiator assembly has been proposed in which an electric initiator and a metal collar that surrounds at least a part of the electric initiator are integrated with resin (for example, Patent Document 2).

[0004] Also proposed is an igniter assembly in which the cup-shaped receiving portion of the igniter is welded to a base portion or the like (for example, Patent Document 3).

[0005] International Publication No. 2020 / 149399 Japanese Patent Application Publication No. 2003-161599 U.S. Patent Application Publication No. 2002 / 0063421

[0006] According to the technology described in Patent Document 1, assembly work is complicated, including processing the flange, crimping work, and attaching the sealing member. On the other hand, when the igniter and collar are integrated using injection-molded resin, there is a risk that airtightness will be impaired due to the shrinkage of the resin during hardening. With the technology described in Patent Document 2, it is necessary to determine the collar structure and select the resin taking the shrinkage rate into consideration, making it difficult to reliably ensure airtightness.

[0007] The technology of the present disclosure has been made in consideration of the above-mentioned problems, and its purpose is to provide a technology for ensuring the airtightness of a combustion chamber.

[0008] The igniter assembly of the present disclosure comprises an ignition device having an igniter including an ignition portion that hermetically accommodates an ignition charge and a conductive portion that supplies an ignition current to ignite the ignition charge, a cylindrical igniter holding portion that surrounds and holds the igniter, and a resin fixing member that is interposed between the igniter and the igniter holding portion and fixes the igniter to the igniter holding portion, a bottomed cylindrical case on one axial side of the igniter holding portion that accommodates a first gas generating agent and the ignition portion of the igniter, and a moisture-impermeable partition wall that partitions the interior of the case into a space in which the igniter and the fixing member are arranged and a space in which the first gas generating agent is accommodated, the partition wall being welded to the igniter holding portion and the case and being welded all around to at least one of the igniter holding portion and the case.

[0009] Because the partition wall is welded to the entire periphery of the igniter holder or the case, it is possible to prevent moisture from entering between the resin fixing part and the surrounding members, for example, thereby ensuring the airtightness of the combustion chamber.

[0010] Furthermore, the thickness of the partition wall may be thinner than the thickness of the igniter holding portion and the thickness of the case, which makes it easier to form a case that splits open appropriately when the igniter is activated.

[0011] The partition wall may be formed of the same material as the igniter holding portion or the case, which facilitates the work of welding the partition wall and the igniter holding portion or the case together.

[0012] The partition wall may be cup-shaped with an opening that opens in one direction, and may include an annular portion at an edge of the opening that protrudes radially outward from the cup shape, and the annular portion may be received in the case so as to be exposed to the outside, and the annular portion may be connected to the igniter holding portion or the case by full-circumference welding. Such a shape makes the full-circumference welding work easier.

[0013] Furthermore, a gas generator according to the present disclosure may include the above-described igniter assembly, a housing that accommodates the igniter assembly and is provided with a gas discharge hole, and a second gas generating agent filled in the housing. The above-described igniter assembly can be incorporated into, for example, such a gas generator.

[0014] The gas generator according to the present disclosure may also include a cylindrical first housing filled with pressurized gas and having both axial ends closed by closing members, a second housing connected to one axial end of the first housing, and the above-mentioned igniter assembly housed in the second housing. The second housing may include a second gas generating agent that is ignited and burned by combustion products generated by the igniter assembly, and the cylindrical case with a bottom may have a through hole in the closed bottom through which combustion products of the first gas generating agent pass, and the through hole may be disposed opposite a closing member that closes one axial end of the first housing.

[0015] According to the present disclosure, it is possible to provide a technique for ensuring the airtightness of a combustion chamber.

[0016] Fig. 1 is a schematic axial cross-sectional view showing an example of an igniter assembly. Fig. 2 is a diagram showing an example of a manufacturing method. Fig. 3 is a diagram showing another example of a manufacturing method. Fig. 4 is a schematic axial cross-sectional view showing an example of a gas generator according to a second embodiment. Fig. 5 is a schematic axial cross-sectional view showing an example of a gas generator including an igniter assembly according to the present disclosure. Fig. 6 is a schematic axial cross-sectional view showing an example of a gas generator according to a modified example. Fig. 7 is a schematic axial cross-sectional view showing an example of a gas generator according to a modified example. Fig. 8 is a schematic axial cross-sectional view showing a modified example of an igniter assembly.

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that each configuration and combination thereof in each embodiment is an example, and addition, omission, substitution, and other modifications of the configuration are possible as appropriate within the scope of the gist of the present invention. The present disclosure is not limited by the embodiments, but is limited only by the claims.

[0018] <Embodiment 1> Fig. 1 is a schematic axial cross-sectional view showing an example of an igniter assembly according to this embodiment. The igniter assembly 1 can be incorporated into, for example, a seat belt retractor of an automobile and used as a gas generator for retracting the seat belt in the event of a collision. The igniter assembly 1 in Fig. 1 includes an igniter device 2, a partition wall 3, and a case 4.

[0019] <Ignition device> The ignition device 2 includes an igniter main body 21 that is ignited by an ignition current, an igniter holding portion 22 that supports the igniter main body 21, and a resin portion 23 (also referred to as a "fixing member") interposed between the igniter main body 21 and the igniter holding portion 22.

[0020] The igniter main body 21 has a metal cup body 211 that houses and seals an ignition charge, and a pair of conductive pins 212, 212 for receiving a current supply from the outside. In this embodiment, for convenience, the cup body 211 side will be described as the upper side and the conductive pins 212, 212 side as the lower side. The igniter main body 21 is activated by an ignition current supplied to the pair of conductive pins 212, 212, causing the ignition charge in the cup body 211 to combust and releasing the combustion products to the outside of the cup body 211.

[0021] Igniter holding portion 22 is, for example, a metal collar that supports the side of igniter body 21. That is, igniter holding portion 22 is a cylindrical metal member that holds igniter body 21 inside. Note that, in order to suppress circumferential rotation of igniter body 21 and resin portion 23, the inner circumferential surface of igniter holding portion 22 that comes into contact with resin portion 23 may be provided with irregularities, and the shape of the hole through which conductive pin 212 passes may be a shape other than a perfect circle, such as a polygon or ellipse, in cross section. Furthermore, igniter holding portion 22 may be fixed, for example, by welding to a housing of a gas generator (not shown).

[0022] The resin portion 23 is a resin member that is interposed between the igniter main body 21 and the igniter holding portion 22 by injection molding and secures the igniter main body 21 to the igniter holding portion 22. The resin portion 23 covers the lateral periphery of the igniter main body 21 so that at least a portion of the cup body 211 is exposed from the resin portion 23. The resin portion 23 also secures the igniter main body 21 to the igniter holding portion 22 by engaging with the inside of the igniter holding portion 22. However, the entire cup body 211 may be overmolded with the resin portion 23. In other words, the entire cup body 211 may be covered with resin. The resin portion 23 may also form a connector insertion space 213 inside the igniter holding portion 22 into which a connector (not shown) that supplies power from an external power source to the pair of conductive pins 212, 212 can be inserted. The resin portion 23 covers and holds a portion of the pair of conductive pins 212, 212 so that the lower ends of the pair of conductive pins 212, 212 are exposed to the connector insertion space 213. The resin portion 23 maintains insulation between the pair of conductive pins 212, 212. Various known techniques can be used to fix the igniter main body 21 to the igniter holding portion 22 and to connect the igniter holding portion 22 to the housing. Resin materials that exhibit excellent heat resistance, durability, corrosion resistance, and the like after curing can be suitably used as the material for the resin portion 23. Examples of such resin materials include, but are not limited to, thermoplastic resins such as polybutylene terephthalate resin, polyethylene terephthalate resin, polyamide resin, polypropylene sulfide resin, and polypropylene oxide resin, as well as thermosetting resins such as epoxy resin.

[0023] <Partition Wall> The partition wall 3 is a member that separates the combustion chamber 42 provided inside the case 4 from the space in which the ignition device 2 is disposed. The partition wall 3 is a cylindrical (i.e., cup-shaped) member with a bottom that is disposed above the igniter holding portion 22. The partition wall 3 is formed of a moisture-impermeable material, such as a metal such as aluminum or iron, or ceramic. In this embodiment, the partition wall 3 has an opening on the igniter holding portion 22 side and is disposed so as to cover the upper part of the cup body 211 of the igniter main body 21. The end of the opening of the partition wall 3 is provided with a flange-like flange portion 31 (also referred to as an "annular portion") that protrudes laterally (i.e., radially outward from the cup-shaped partition wall) around the entire periphery. The flange portion 31 may be connected to the upper surface of the igniter holding portion 22 by, for example, welding. The flange portion 31 and the igniter holding portion 22 may be fixed by a known method other than welding (e.g., by crimping). In this case, it is preferable that the material of the partition wall 3 is the same as that of the igniter holding portion 22, as this facilitates welding. The partition wall 3 functions as a cover to prevent moisture from entering the igniter assembly 1 before the igniter assembly 1 is activated. When the igniter assembly 1 is activated, the ignition charge is ignited, and the cup body 211 ruptures, the partition wall 3 bursts. To ensure proper bursting, the thickness of the partition wall 3 may be thinner than that of the igniter holding portion 22 and that of the case 4. For example, if the thickness of the case 4 is 0.8 mm to 1.5 mm, the thickness of the partition wall 3 may be 0.1 mm to 1.0 mm. An insulating layer, such as a space or an insulating sheet, may be provided between the partition wall 3 and the igniter 2. By insulating the igniter 2 from the housing 6, malfunction of the igniter 2 due to static electricity accumulated in the housing 6 can be prevented. In particular, when the partition wall 3 comes into contact with the cup body 211, it is preferable to place an electrically insulating member such as an insulating sheet between them.

[0024] <Case> The case 4 is a cylindrical member with a bottom that extends upward from the igniter holding portion 22 so as to surround the upper portion of the ignition device 2. That is, the case 4 is formed in a cylindrical shape with one end (upper end) closed and the other end (lower end) open. The other end of the case 4 has a flange portion 41 that protrudes laterally along the entire circumference. The flange portion 41 may be connected to the flange portion 31 of the partition wall 3 by, for example, full-circumference welding. Full-circumference welding refers to a continuous, annular weld in the circumferential direction, and refers to sealing a gap that occurs between two components to be welded. A combustion chamber 42, which is an internal space that accommodates a transfer charge 5 (also referred to as a "first gas generant"), is formed between the case 4 and the partition wall 3. The transfer charge 5 burns when the igniter body 21 is activated, generating combustion gases and the like. The side of the case 4 has a plurality of communication holes 43 that communicate the combustion chamber 42 with the external space. Before the ignition device 2 is activated, the communication hole 43 is blocked with a sealing tape (not shown). When the ignition device 2 is activated, the pressure of the combustion gas tears the sealing tape, allowing the combustion gas to be discharged from the communication hole 43 to the outside of the combustion chamber 42. The communication hole 43 only needs to communicate between the inside and outside of the combustion chamber 42 at least when the ignition device 2 is activated. It may be blocked with a blocking member other than a sealing tape, or it may not be blocked with a sealing tape or the like. Furthermore, the communication hole 43 may be formed in the top surface of the case 4, rather than the side surface. Instead of the communication hole 43, a slit or thin-walled portion serving as a fragile portion may be formed in the side surface or top surface of the case 4, and the fragile portion may be opened (for example, the fragile portion or groove disclosed in JP-A-2005-238948-21 or JP-A-2002-200420-10c).

[0025] <Gas Generating Agent> A predetermined gas generating agent is used for the enhancer charge 5. The combustion temperature of the enhancer charge 5 is, for example, 1000 to 1700°C. The enhancer charge 5 is formed, for example, from guanidine nitrate (41% by weight), basic copper nitrate (49% by weight), a binder, and an additive. The shape of each enhancer charge 5 may be a single-hole cylindrical shape. However, the shape of the enhancer charge 5 is not limited to the above.

[0026] <Manufacturing Method 1> The igniter assembly 1 shown in FIG. 1 can be manufactured by various methods. FIG. 2 shows one example of the manufacturing method. As shown in FIG. 2 (1), first, the transfer charge 5 is filled into the case 4, and then the partition wall 3 is inserted into the case 4 as shown in FIG. 2 (2). In (2), the case 4 receives the transfer charge 5, with the flange portion 31 provided at the edge of the opening of the partition wall 3 exposed to the outside. Furthermore, as shown in (3), the igniter body 21 is inserted into the partition wall 3, and the igniter holder 22, the partition wall 3, and the case 4 are welded all around as shown in (4). That is, the flange portion 31 of the partition wall 3 and the flange portion 41 of the case 4 are placed on top of the igniter holder 22, and then the flange portions 31 and 32 are continuously melted and connected all around by laser welding or the like. In FIG. 2, the black oval portions are welded. Although full circumferential welding was performed for the convenience of assembly, in the embodiment of Figures 1 and 2, when igniter assembly 1 is used alone as a gas generator, it is sufficient that flange portion 31 and flange portion 41 are fully circumferentially welded, and flange portion 31 and igniter holding portion 22 do not need to be fully circumferentially welded.

[0027] <Manufacturing Method 2> The igniter assembly 1 shown in FIG. 1 may be manufactured by another method. FIG. 3 shows another example of the manufacturing method. As shown in FIG. 3 (1), first, the transfer charge 5 is filled into the case 4. Then, as shown in FIG. 3 (2), the partition wall 3 is inserted into the case 4, and the partition wall 3 and the case 4 are welded all around. That is, the flange portion 31 of the partition wall 3 and the flange portion 41 of the case 4 are continuously melted and connected all around by laser welding or the like. In FIG. 3 as well, the black oval portion is assumed to be welded. Next, as shown in FIG. 3 (3), the igniter device 2 is attached so that the igniter main body 21 is inserted inside the partition wall 3, and as shown in FIG. 3 (4), the igniter device 2 is fixed to the flange portion 31 of the partition wall 3 and the flange portion 41 of the case 4 by, for example, crimping a portion of the igniter holder 22.

[0028] <Effects> The following describes the case where the igniter assembly 1 shown in Figures 1, 2, or 3 is used alone as a gas generator. The case where the igniter assembly 1 is used in combination with other components as a gas generator is described later. When the igniter and the igniter holder are integrated using injection-molded resin, airtightness may be compromised due to resin shrinkage during hardening. For example, gaps may occur between the igniter holder 22 and the resin portion 23 or between the conductive pin 212 and the resin portion 23. By fixing the partition wall 3 of the igniter assembly 1 as described above, the combustion chamber 42 and the space in which the igniter 2 is disposed are separated, and moisture can be prevented from entering the combustion chamber 42 through the gap between the resin portion 23 and surrounding components. In other words, because the partition wall 3 and the case 4 are welded all around, there is no risk of moisture entering the combustion chamber 42 through the gap between them. According to the igniter assembly 1 described above, because the partition wall 3 is moisture impermeable, even if there is a gap between the igniter holding portion 22 and the partition wall 3, moisture that penetrates through the gap will not enter the combustion chamber 42. In other words, the airtightness of the combustion chamber 42 can be ensured. Therefore, in this embodiment, in order to ensure the airtightness of the combustion chamber 42, it is preferable to connect the flange portion 41 of the case 4 and the flange portion 31 of the partition wall 3 by at least full-circumference welding, and the igniter holding portion 22 and the flange portion 31 of the partition wall 3 do not need to be full-circumference welded, and they may be fixed by partial welding or another fixing method. Of course, the igniter holding portion 22 and the flange portion 31 may also be full-circumference welded.

[0029] According to the first embodiment described above, airtightness inside the case can be ensured with a single welding process, and additional sealing materials such as gaskets, O-rings, or sealants are not required. Furthermore, by welding the outermost peripheral portions of the flange-shaped portions (flange portion 31, flange portion 41) together, the effect of welding heat on the transfer charge 5 inside the case can be suppressed. In particular, in the manufacturing method shown in FIG. 2, by setting the welding points for the igniter holding portion 22 to the outermost peripheral portions, the effect of welding heat on the resin portion 23 (such as resin deformation) can be minimized. When attaching the igniter assembly 1 shown in FIGS. 1 to 3 to a seat belt retractor, the annular step formed in the mounting opening on the retractor side is abutted against the flange portion 41, and the open end of the mounting opening is crimped against the end face of the igniter holding portion 22 (the end face opposite the end face where the flange portions 31, 41 are attached). This clamps the flange portions 31, 41 to the retractor, and the flange portions 31, 41 maintain abutment with each other even during operation.

[0030] 4 is a schematic cross-sectional view showing an example of a gas generator according to embodiment 2. An igniter assembly 1 according to this embodiment also includes an igniter 2, a partition wall 3, and a case 4. Note that components corresponding to those in embodiment 1 described above are given the same reference numerals, and descriptions thereof will be omitted.

[0031] Case 4 of igniter assembly 1 has an annular opening-side end 44 that extends downward, and does not have flange 41 as shown in FIG. 1 . Igniter holder 22 is inserted inside case 4, and case 4 is welded to igniter holder 22 around its entire circumference. In the present embodiment, flange 31 of partition wall 3 and igniter holder 22 may also be connected by welding. Even with this configuration, moisture can be prevented from entering between resin portion 23 and surrounding components, ensuring the airtightness of combustion chamber 42.

[0032] <Manufacturing Method> In the present embodiment, the partition wall 3 is placed over the igniter 2, and the igniter 2 and the partition wall 3 are welded together. That is, the upper surface of the igniter holding portion 22 and the flange portion 31 of the partition wall 3 are melted and connected by laser welding or the like. After the transfer charge 5 is filled into the case 4 and the igniter 2 and the partition wall 3 are inserted into the case 4, the case 4 and the igniter holding portion 22 are continuously welded circumferentially from the outer periphery (full-circumference welding). It is preferable to weld the flange portion 31 of the partition wall 3 and the portion of the igniter holding portion 22 that abut against the case 4 from the outside all the way around, since this allows for a single welding operation. When the igniter assembly 1 of FIG. 4 is also used alone as a gas generator, the case 4, the partition wall 3, and the igniter holding portion 22 are fixed as described above.

[0033] <Gas Generator> Fig. 5 is a schematic cross-sectional view showing an example of a gas generator including an igniter assembly according to the present disclosure. The gas generator 10 includes an igniter assembly 1, a housing 6, and a filter 7. The gas generator 10 shown in Fig. 5 is a so-called single-type device including one igniter assembly 1. The gas generator 10 combusts a second gas generating agent 8 filled inside the housing 6 by activating an igniter 2 disposed inside the housing 6. Note that while the gas generator 10 shown in Fig. 5 includes the igniter assembly 1 shown in Fig. 1, it may instead include the igniter assembly 1 shown in Fig. 4. However, when the igniter assemblies of Figs. 1 and 4 are used as ignition means in the gas generator 10, the welding conditions between the case 4, the partition wall 3, and the igniter holder 22 may differ, as described below.

[0034] 5, the housing 6 is formed into a short cylindrical shape with both axial ends closed by joining an upper shell 61 and a lower shell 62, each of which is made of metal and has a cylindrical shape with a bottom, with their open ends facing each other. However, the configurations of the upper shell 61 and the lower shell 62 are not limited to this, and known shells can be used as appropriate.

[0035] The upper shell 61 has a cylindrical upper tube portion 612, a top plate portion 611 closing the upper end of the upper tube portion 612, and a flange-shaped joint portion 613 extending radially outward from the lower end of the upper tube portion 612. The lower shell 62 has a cylindrical lower tube portion 622, a bottom plate portion 621 closing the lower end of the lower tube portion 622, and a flange-shaped joint portion 623 extending radially outward from the upper end of the lower tube portion 622. The joint portion 613 of the upper shell 61 and the joint portion 623 of the lower shell 62 are overlapped and joined by welding or the like to form the housing 6. The upper tube portion 612 of the upper shell 61 has a plurality of gas exhaust holes 614 arranged circumferentially, communicating between the inside and outside of the housing 6. Before operation of the gas generator 10, the gas exhaust holes 614 are closed by a blocking member such as sealing tape (not shown).

[0036] Furthermore, the igniter holding portion 22 of the igniter assembly 1 is connected to the lower shell 62 of the housing 6. The igniter holding portion 22 may be a metal collar joined to the bottom plate portion 621 by full-circumference welding. The igniter holding portion 22 may be formed integrally with the bottom plate portion 621. In other words, the metal igniter holding portion 22 may be formed by a part of the lower shell 62 of the housing 6. The igniter holding portion 22 is provided so as to protrude upward from the bottom plate portion 621 into the interior of the housing 6. The igniter holding portion 22 constitutes the ignition device 2 shown in FIG. 1 or 4.

[0037] <Filter> The filter 7 is formed in a cylindrical shape and is disposed between the igniter assembly 1 and the gas discharge hole 614, with its upper end supported by the top plate portion 611 of the upper shell 61 and its lower end supported by the bottom plate portion 621 of the lower shell 62. This forms a combustion chamber 101 between the igniter assembly 1 and the filter 7. The combustion chamber 101 is filled with a second gas generating agent 8 that burns upon activation of the igniter assembly 1. The second gas generating agent 8 is ignited by combustion gas from the transfer charge 5 (first gas generating agent) that is burned upon activation of the igniter assembly 1, thereby generating combustion gas. The filter 7 is configured to allow combustion gas to pass through, and the combustion gas in the combustion chamber 101 is cooled as it passes through the filter 7. At this time, the filter 7 filters the combustion gas by collecting combustion residue of the combustion gas.

[0038] <Gas Generating Agent> The second gas generating agent 8 may be the same as the transfer charge 5. However, the second gas generating agent 8 is not limited to the above. The transfer charge 5 and the second gas generating agent 8 may be gas generating agents of the same type, shape and size, or may be gas generating agents of different types, shapes and sizes.

[0039] <Operation> When gas generator 10 is installed in an automobile or the like, a connector (not shown) inserted into connector insertion space 213 is connected to a pair of conductive pins 212, 212, enabling power to be supplied to igniter main body 21. In this state, when a sensor (not shown) mounted on the automobile or the like detects an impact, power from an external power source (not shown) is supplied to the pair of conductive pins 212, 212 via the connector, causing the ignition charge in cup body 211 to combust.

[0040] As the ignition charge burns, the pressure inside the cup body 211 rises, causing the cup body 211 to burst, releasing high-temperature flames and gases that are combustion products of the ignition charge. This also splits the partition wall 3, igniting the enhancer charge 5 inside the case 4. The pressure of the combustion gas from the enhancer charge 5 then splits the sealing tape that closes the communication hole 43. The combustion gas from the enhancer charge 5 is discharged from the communication hole 43 into the combustion chamber 101.

[0041] The second gas generating agent 8 is ignited by the combustion gas of the transfer charge 5 discharged from the communication hole 43 into the combustion chamber 101, thereby generating combustion gas of the second gas generating agent 8 within the combustion chamber 101. The combustion gas within the combustion chamber 101 is cooled and filtered by the filter 7, then breaks the sealing tape that has been blocking the gas discharge hole 614, and is discharged from the gas discharge hole 614 to the outside of the housing 6. This causes, for example, an airbag to inflate.

[0042] In the embodiment of Fig. 5, igniter assembly 1 is used as ignition means in gas generator 10. Igniter assembly 1 is disposed in sealed housing 6. Therefore, moisture intrusion from the outside occurs mainly between conductive pin 212 and resin portion 23, and between igniter holding portion 22 and resin portion 23. Therefore, in the igniter assembly of the embodiment of Fig. 5, moisture intrusion can be prevented by welding partition wall 3 to igniter holding portion 22 all around. The joining of case 4 and partition wall 3 may or may not be all around welding, and other known fixing methods may be used.

[0043] <Gas Generator 2> Figure 6 is a schematic cross-sectional view showing an example of a gas generator according to a modified example. Components corresponding to those in the gas generator 10 described above are assigned the same reference numerals, and descriptions thereof will be omitted. A gas generator 11 according to a modified example includes a pressurized gas section 91, a diffuser section 92, and an ignition section 93 including an igniter assembly 1. While the gas generator 11 shown in Figure 6 includes the igniter assembly 1 shown in Figure 1, it may instead include the igniter assembly 1 shown in Figure 4. In this case, the welding conditions between the case 4, the partition wall 3, and the igniter holder 22 may differ, as described below. The gap between the ignition section 93 and the igniter holder 22 is sealed with a known sealing means, such as an O-ring.

[0044] The pressurized gas unit 91 has a cylindrical first housing 911 that forms an outer shell, and a pressurized gas chamber 912 filled with pressurized gas is formed inside the first housing 911. The pressurized gas filled in the pressurized gas chamber 912 may be, for example, argon, helium, or a pressurized gas consisting of a mixture of these. A pressurized gas filling hole 913 is formed in the side surface of the first housing 911, and with the pressurized gas filling the pressurized gas chamber 912 through the filling hole 913, the filling hole 913 is closed by a closing pin 914.

[0045] The ignition unit 93 has a cylindrical second housing 6 that forms an outer shell, and a second gas generating agent 8 is accommodated in a combustion chamber 101 formed inside the second housing 6. The igniter assembly 1 is accommodated in one end of the second housing 6, and the other end of the second housing 6 is connected to one end of the pressurized gas unit 91. The housing 6 and the first housing 911 are welded at a joint 915. Note that, as shown in FIG. 6 , the communication hole 43 provided in the case 4 of the igniter assembly 1 may be provided on the top surface of the case 4.

[0046] A first communication hole 916 between the pressurized gas portion 91 and the ignition portion 93 is closed by a cup-shaped first rupturable plate 917 (also referred to as a "first closing member"), and the inside of the ignition portion 93 is maintained at normal pressure. The first rupturable plate 917 is welded to the second housing 6 at its peripheral edge.

[0047] A cap 919 having a gas discharge hole 918 is placed on the first rupturable plate 917 from the pressurized gas portion 91 side. This cap 919 is attached at a position where the combustion gas generated by the combustion of the second gas generating agent 8 is ejected from the gas discharge hole 918 by covering the first rupturable plate 917.

[0048] The cap 919 has a flange portion that protrudes outward from the periphery of the opening, and is fixed by crimping a part of the housing 6 at the flange portion.

[0049] A diffuser portion 92 having gas discharge holes 921 for discharging the pressurized gas and combustion gas is connected to the other end of the pressurized gas portion 91, and the diffuser portion 92 and the first housing 911 are welded at a joint 922. The diffuser portion 92 is a cap-shaped member having a plurality of gas discharge holes 921 for allowing gas to pass through.

[0050] A second communication hole 923 between the pressurized gas portion 91 and the diffuser portion 92 is closed by a second rupturable plate 924 (also referred to as a "second closing member"), and the inside of the diffuser portion 92 is maintained at normal pressure. The second rupturable plate 924 is welded to the diffuser portion 92 at a peripheral edge 925.

[0051] <Operation> For example, when an automobile collides and receives an impact, the igniter assembly 1 is activated by the activation signal output means, causing the second gas generating agent 8 to combust and generate combustion gas. Thereafter, the combustion gas increases the pressure inside the second housing 6, causing the first rupturable disc 917 to rupture, and the combustion gas flows into the cap 919 and is ejected from the gas discharge hole 918. Furthermore, the pressure inside the pressurized gas chamber 912 increases, causing the second rupturable disc 924 to break, and the pressurized gas and combustion gas pass through the second communication hole 923 and are discharged from the gas discharge hole 921, causing, for example, an airbag to inflate.

[0052] As in the embodiment of FIG. 5, the embodiment of FIG. 6 is used as a gas generator in which the igniter assembly 1 is incorporated as an ignition device, and therefore the welding state of the case 4, the partition wall 3 and the igniter holding portion 22 is the same as in FIG. 5.

[0053] <Gas Generator 3> Figure 7 is a schematic cross-sectional view showing an example of a gas generator according to a modified example. Components corresponding to those in the gas generators 10 and 11 described above are given the same reference numerals, and descriptions thereof will be omitted. Gas generator 11 according to this modified example also includes a pressurized gas section 91, a diffuser section 92, and an ignition section 93 including the igniter assembly 1 shown in Figure 1 or 4. While gas generator 11 shown in Figure 7 also includes the igniter assembly 1 shown in Figure 1, it may instead include the igniter assembly 1 shown in Figure 4. In this case, the welding state of case 4, partition wall 3, and igniter holder 22 is the same as in Figure 5, as shown in Figure 6.

[0054] The ignition section 93 according to this modification is disposed so that the communication hole 43 of the case 4 and the first rupture disk 917 face each other. The ignition section 93 does not include a combustion chamber 101 that accommodates the second gas generating agent 8. The ignition section 93 ruptures the first rupture disk 917 with the combustion products of the transfer charge 5. The gas generator 11 may have such a configuration. Similar to the embodiment in FIG. 5 , the embodiment in FIG. 7 is used as a gas generator in which the igniter assembly 1 is incorporated as an ignition device, and therefore the welding state of the case 4, the partition wall 3, and the igniter holding section 22 is the same as that in FIG. 5 .

[0055] <Modification of Igniter Assembly> Fig. 8 is a schematic axial cross-sectional view showing a modification of the igniter assembly. Note that components corresponding to those in the first embodiment described above are given the same reference numerals, and descriptions thereof will be omitted.

[0056] In the example of Fig. 8, the partition wall 3 is welded to the case 4 all around. The case 4 is also fixed to the igniter holding portion 22 by welding. The case 4 may also be connected to the igniter holding portion 22 by crimping. As shown in Fig. 8, the partition wall 3 does not have the flange portion 31 shown in Fig. 1, etc., and the partition wall 3 is not in contact with the igniter holding portion 22. Even in this embodiment, the airtightness of the combustion chamber 42 can be ensured.

[0057] In summary, by separating the space in which the igniter body 21 and the resin portion 23 are disposed from the space in which the transfer charge 5 is accommodated by the partition wall 3, the airtightness of the combustion chamber 42 in which the transfer charge 5 is accommodated can be ensured even if the resin portion 23 shrinks during hardening. In this case, it is desirable that the partition wall 3 be fixed in contact with the case 4 to close one end of the combustion chamber 42. It is also desirable that the partition wall 3 be fully welded to at least one of the igniter holding portion 22 and the case 4. For example, as in the first embodiment, the second embodiment, and the above-mentioned modified examples, the airtightness of the combustion chamber 42 formed inside the case 4 can be ensured by fully welding the partition wall 3 to the case 4. Furthermore, as shown in Figure 5, etc., when a product is provided in which igniter assembly 1 is housed in a sealable housing 6, and igniter holding portion 22 and housing 6 are welded all around, even if partition wall 3 and igniter holding portion 22 are welded all around, the airtightness of the space formed inside partition wall 3 and housing 6, including combustion chamber 42, can be ensured.

[0058] <Others> Although embodiments of the igniter assembly and gas generator according to the present disclosure have been described above, each aspect disclosed herein can be combined with other features disclosed herein. Furthermore, while the above embodiments have been described using a single-type gas generator equipped with one igniter assembly 1 as an example, the present disclosure may also be applied to a gas generator equipped with multiple igniter assemblies 1. Furthermore, the igniter assembly 1 may also be applied to devices other than gas generators for seat belt retractors or airbags.

[0059] 1 to 7 may be a resin that has been injection molded and hardened between igniter main body 21 and igniter holding portion 22. When igniter main body 21 and igniter holding portion 22 are integrated by injection molding, there is a risk that gaps will form between igniter holding portion 22 and resin portion 23 or between igniter main body 21 and resin portion 23 after the resin has hardened. However, according to the above-described igniter assembly 1, it is possible to prevent moisture from entering through the gaps.

[0060] 2 and 3 , the flange portion 41 is the outermost peripheral portion of the case 4, and the flange portion 31 is the outermost peripheral portion of the partition wall 3. That is, the outermost peripheral portions of the case 4 and the partition wall 3 are brought into contact with each other. The contact point between these outermost peripheral portions may then be welded all around the igniter holding portion 22. In particular, by positioning the welding point in the igniter holding portion 22 as far as possible from the gas generating agent 8 in the housing 6 and the resin portion 23, it is possible to reduce the effects of heat generated by welding, such as deterioration and misfire of the gas generating agent 8 and deformation of the resin portion 23.

[0061] 4 , the case 4 and the partition wall 3 may be welded together. That is, the side surface that is the outermost periphery of the case 4 and the outermost periphery of the flange portion 31 of the partition wall 3 are welded all around together with the igniter holding portion 22. In the second embodiment as well, by positioning the welding location at a radially outer portion of the cylindrical igniter assembly 1, the welding location is located as far as possible from the gas generating agent 8 in the housing 6 and the resin portion 23, and the effects of deterioration and misfire of the gas generating agent 8, deformation of the resin portion 23, and the like, caused by heat generated by welding can be reduced.

[0062] 6 and 7 , igniter assembly 1 may also be fixed by crimping, similar to cap 919. That is, igniter assembly 1 may be inserted into igniter portion 93 so that flange portions 31, 41 abut against an annular stepped portion formed inside the lower end side of igniter portion 93, and the lower end portion of igniter portion 93 may be crimped and fixed so as to sandwich flange portions 31, 41.

[0063] 1: Igniter assembly 2: Igniter device 21: Igniter body 211: Cup body 212: Conductive pin 213: Connector insertion space 22: Igniter holding portion 23: Resin portion 3: Partition wall 31: Flange portion 4: Case 41: Flange portion 5: Transfer charge (first gas generating agent) 10, 11: Gas generator 101: Combustion chamber 6: Housing (second housing) 61: Upper shell 62: Lower shell 7: Filter 8: Second gas generating agent 91: Pressurized gas portion 92: Diffuser portion 93: Igniter portion

Claims

1. an ignition device including an igniter including an ignition part that hermetically accommodates an ignition charge and a conductive part that supplies an ignition current for igniting the ignition charge, a cylindrical igniter holding part that holds the igniter in a state where the igniter is surrounded, and a resin fixing member that is interposed between the igniter and the igniter holding part and fixes the igniter to the igniter holding part; a bottomed cylindrical case that accommodates a first gas generating agent and the ignition portion of the igniter on one side of the axial direction of the igniter holding portion; a moisture impermeable partition wall that partitions the inside of the case into a space in which the igniter and the fixing member are disposed and a space in which the first gas generating agent is accommodated, Equipped with The partition wall is fixed in contact with the case, and is welded all around to at least one of the igniter holding portion and the case. Igniter assembly.

2. The thickness of the partition wall is smaller than the thickness of the igniter holding portion and the thickness of the case. The igniter assembly of claim 1 .

3. The partition wall is formed of the same material as the igniter holding portion or the case.

3. An igniter assembly according to claim 1 or 2.

4. The partition wall is cup-shaped with an opening that opens in one direction, and includes an annular portion at an edge of the opening that protrudes radially outward from the cup shape, and is received in the case so that the annular portion is exposed to the outside. The annular portion is connected to the igniter holding portion or the case by full-circumference welding.

3. An igniter assembly according to claim 1 or 2.

5. The partition wall is welded to the igniter holding portion and the case.

3. An igniter assembly according to claim 1 or 2.

6. The partition wall is welded to the case all around.

3. An igniter assembly according to claim 1 or 2.

7. An igniter assembly according to claim 1 or 2; a housing that accommodates the igniter assembly and has a gas exhaust hole; A second gas generating agent is filled in the housing; A gas generator comprising:

8. The partition wall is welded to the igniter holding portion all around, The igniter holding portion of the igniter assembly is welded to the housing all around.

8. The gas generator of claim 7.

9. a cylindrical first housing filled with pressurized gas and having both axial ends closed by closing members; a second housing connected to one of both ends in the axial direction of the first housing; The igniter assembly according to claim 1 or 2, which is housed in the second housing; and A gas generator comprising:

10. The second housing contains a second gas generant that is ignited and combusted by combustion products generated by the igniter assembly.

10. The gas generator of claim 9.

11. the case is a cylindrical case with a bottom, and has a through hole at a closed bottom through which a combustion product of the first gas generating agent passes; The through hole and the closing member closing one of the two ends in the axial direction of the first housing are disposed opposite to each other.

11. The gas generator of claim 10.