Gas generator

Abstract

This gas generator comprises: a housing; and an igniter assembly which demarcates, together with the housing, an accommodation space for accommodating therein a gas source. The igniter assembly has: an igniter; a color member; a resin member by which the igniter and the color member are joined integrally to each other; and a metallic cover member which encloses an ignition unit and the resin member so as to seal the igniter and the resin member with respect to the accommodation space and which is configured so as to cleave when the igniter is activated. The entire perimeter of the cover member is welded to the color member so as to span the boundary between the resin member and the color member.

Description

Gas generator

[0001] The present invention relates to a gas generator.

[0002] Conventionally, gas generators that accommodate a gas source in an accommodation space formed within a housing and release gas to the outside by activating an igniter have been widely known (for example, Patent Document 1). This type of gas generator is used, for example, to supply gas to an airbag or a seat belt retractor. As the igniter used in a gas generator, an electric igniter that is activated by an ignition current is mainly known. Gas generators that use an electric igniter typically employ a structure in which an igniter assembly is formed by integrally joining the electric igniter and a metal collar member via a resin member, and the igniter assembly is attached to a mounting hole formed in the housing.

[0003] US Patent Application Publication No. 2012 / 234839 German Patent Application Publication No. 102013110810

[0004] Here, from the viewpoint of stabilizing the performance of the gas generator, it is preferable that the accommodation space in which the gas source is accommodated be maintained airtight from the outside. However, in conventional gas generators, there is a risk that moisture will enter the accommodation space through the boundary between the collar member and the resin member, or that the gas source will leak to the outside of the accommodation space.

[0005] The technology of the present disclosure has been made in consideration of the above-mentioned problems, and its purpose is to provide a technology that can improve the airtightness (sealing ability) of the storage space in a gas generator that stores a gas source.

[0006] In order to solve the above problems, the technology of the present disclosure employs the following configuration: That is, the technology of the present disclosure provides a gas generator including a housing having an igniter mounting hole formed therein, and an igniter assembly attached to the housing so as to close the igniter mounting hole and defining, together with the housing, an accommodation space in which a gas source is accommodated, wherein the igniter assembly is an igniter including an ignition section formed with an ignition chamber in which an ignition charge is accommodated, and a conductive section to which an ignition current for igniting the ignition charge is supplied, the ignition section being positioned closer to the interior of the accommodation space than the conductive section, and configured so that the ignition section is cleaved when activated by the ignition current supplied to the conductive section, thereby releasing a combustion product of the ignition charge. a metallic collar member formed in a cylindrical shape and inserted into an igniter mounting hole so as to surround the igniter; a resin member made of resin arranged between the igniter and the collar member, the resin member joining the igniter and the collar member together with at least the conductive portion exposed from the resin member; and a metallic cover member surrounding the ignition portion and the resin member so that the igniter and the resin member are sealed from the accommodating space and configured to split when the igniter is activated, wherein the cover member is welded all around to the collar member across the boundary line between the resin member and the collar member.

[0007] In the gas generator according to the present disclosure, the accommodation space may accommodate a gas generating agent and pressurized gas as the gas source.

[0008] Moreover, in the gas generator according to the present disclosure, the cover member may be formed so that a space is secured between the cover member and a cleavage portion that is a portion of the ignition portion that cleaves.

[0009] Furthermore, in the gas generator according to the present disclosure, the ignition portion may have a cup body including a cylindrical peripheral wall portion and a lid wall portion closing one end of the peripheral wall portion and formed as the rupture portion, and a closure member arranged to close an opening formed in the other end of the peripheral wall portion and defining the ignition chamber together with the cup body, and is configured so that when the igniter is activated, the lid wall portion ruptures, thereby releasing combustion products of the ignition charge to the outside of the ignition chamber, and the cover member may have a cylindrical peripheral wall opposing portion arranged opposite to and in contact with the peripheral wall portion, and a dome-shaped lid wall opposing portion formed opposite to the lid wall portion and convex toward the storage space.

[0010] Furthermore, in the gas generator according to the present disclosure, the ignition portion has a cup body including a cylindrical peripheral wall portion and a lid wall portion closing one end of the peripheral wall portion and formed as the rupture portion, and a closure member that is arranged to close an opening formed in the other end of the peripheral wall portion and that defines the ignition chamber together with the cup body, and is configured such that when the igniter is activated, the lid wall portion ruptures to release combustion products of the ignition charge, and the ignition portion may further have a cylindrical charge holder that is arranged in the ignition chamber to face the peripheral wall portion and surround the ignition charge while being in contact with the peripheral wall portion.

[0011] Furthermore, in the gas generator according to the present disclosure, the ignition portion has a cup body including a cylindrical peripheral wall portion and a lid wall portion closing one end of the peripheral wall portion and formed as the cleavage portion, and a closure member arranged to close an opening formed in the other end of the peripheral wall portion and defining the ignition chamber together with the cup body, and is configured such that when the igniter is activated, the lid wall portion cleaves to release combustion products of the ignition charge, and the cover member may cleave when the lid wall portion cleaves so that the combustion products are radiated in a concentrated manner toward the cover member.

[0012] Furthermore, in the gas generator according to the present disclosure, the ignition portion has a cup body including a cylindrical peripheral wall portion and a lid wall portion closing one end of the peripheral wall portion and formed as the rupture portion, and a closure member arranged to close an opening formed in the other end of the peripheral wall portion and defining the ignition chamber together with the cup body, and is configured such that when the igniter is activated, the lid wall portion ruptures to release combustion products of the ignition charge, and the cover member may rupture when the lid wall portion ruptures so as to come into contact with the cover member.

[0013] In the gas generator according to the present disclosure, the collar member may be welded to the housing along its entire periphery.

[0014] According to the present disclosure, in a gas generator, the airtightness of the accommodation space in which the gas source is accommodated can be improved.

[0015] FIG. 1 is a cross-sectional view showing a state before activation of the gas generator according to the first embodiment. FIG. 2 is a cross-sectional view showing a state in the vicinity of the igniter assembly before activation of the gas generator according to the first embodiment. FIG. 3 is a top view of an inner cup of a cup body according to the first embodiment. FIG. 4 is a cross-sectional view showing a state in the vicinity of the igniter assembly when the gas generator according to the first embodiment is activated and the ignition portion is torn open. FIG. 5 is a cross-sectional view showing a state in the vicinity of the igniter assembly when the gas generator according to the first embodiment is activated and the cover member is torn open. FIG. 6 is a cross-sectional view showing a state in the vicinity of the igniter assembly before activation of the gas generator according to a first modification of the first embodiment. FIG. 7 is a cross-sectional view showing a state in the vicinity of the igniter assembly when the gas generator according to the first modification of the first embodiment is activated and the cover member is torn open. FIG. 8 is a cross-sectional view showing a state in the vicinity of the igniter assembly before activation of the gas generator according to a second modification of the first embodiment. FIG. 9 is a cross-sectional view showing a state in the vicinity of the igniter assembly before activation of the gas generator according to the second embodiment.

[0016] Embodiments of the present disclosure will be described below with reference to the drawings. In the embodiments described below, the technology according to the present disclosure is applied to a gas generator (inflator) for an airbag. However, the use of the technology according to the present disclosure is not limited thereto, and the technology may also be applied to a gas generator for a seatbelt retractor, for example. Note that the configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible as appropriate within the scope of the present invention. The present disclosure is not limited by the embodiments, but is limited only by the claims. Note that, in this specification, "circumferential welding" refers to a continuous, annular weld in the circumferential direction, which closes any gap that occurs between two members to be welded.

[0017] <Embodiment 1> Fig. 1 is a cross-sectional view showing a state before activation of a gas generator for an airbag (hereinafter simply referred to as a gas generator) 100 according to Embodiment 1. Fig. 1 shows a cross section along the axial direction of a housing designated by reference numeral 1. The gas generator 100 according to this embodiment is configured as a so-called single-type gas generator including one igniter. The gas generator 100 may also be configured as a so-called hybrid-type gas generator using a gas generating agent and pressurized gas as the gas source. However, the technology according to the present disclosure is not limited to these. In other words, the gas generator according to the present disclosure may be provided with a plurality of igniters. The gas generator according to the present disclosure may also be configured as a so-called pyro-type gas generator using only a gas generating agent as the gas source, or as a so-called stored-type gas generator using only pressurized gas as the gas source.

[0018] [Overall Configuration] As shown in Fig. 1 , gas generator 100 includes a cylindrical housing 1 in which an igniter mounting hole 111 is formed, and an igniter assembly 2 attached to housing 1 so as to close igniter mounting hole 111. Housing 1 and igniter assembly 2 define an accommodating space 10. A gas generating agent 20 and pressurized gas are accommodated in this accommodating space 10 as a gas source. Gas generator 100 also includes a holder 7 that is arranged in accommodating space 10 so as to surround igniter assembly 2 and gas generating agent 20. Here, the direction along the axial direction of housing 1 is defined as the up-down direction of gas generator 100, with the igniter assembly 2 side (i.e., the lower side in Fig. 1 ) being the lower side of gas generator 100 and the opposite side (i.e., the upper side in Fig. 1 , the diffuser portion side indicated by reference numeral 12) being the upper side of gas generator 100.

[0019] The gas generator 100 is, for example, an inflator for an airbag, and is a device that supplies an operating gas to an airbag (not shown) when activated to inflate the airbag. The gas generator 100 burns the gas generating agent 20 filled in the accommodating space 10 by activating the igniter 3 included in the igniter assembly 2, and releases the combustion gas, which is a combustion product, together with pressurized gas to the outside of the housing 1, thereby inflating the airbag (not shown). Each component of the gas generator 100 will be described below.

[0020] [Housing] As shown in FIG. 1 , the housing 1 has a metal housing main body 11, a diffuser portion 12, and a rupture disc 13. The housing main body 11 is formed in a cylindrical shape with both ends open. An opening at one end (lower end) of the housing main body 11 is formed as an igniter mounting hole 111 for mounting the igniter assembly 2. Furthermore, an opening at the other end (upper end) of the housing main body 11 is formed as a diffuser mounting hole 112 for mounting the diffuser portion 12. Furthermore, a fill hole 113 that communicates between the inside and outside of the housing 1 is formed in a side surface of the housing main body 11. The fill hole 113 is closed by a closing pin 114 when the storage space 10 is filled with pressurized gas through the fill hole 113.

[0021] As shown in Fig. 1 , the diffuser portion 12 is formed in a stepped, bottomed cylindrical shape. Specifically, the diffuser portion 12 has a gas discharge portion 121 that includes a closed end thereof, and an insertion portion 122 that includes an open end thereof and has a larger diameter than the gas discharge portion 121. A gas discharge hole 14 that communicates between the inside and outside of the diffuser portion 12 is formed in the peripheral wall of the gas discharge portion 121. With the insertion portion 122 inserted into the diffuser mounting hole 112 of the housing main body 11 and the gas discharge portion 121 protruding out of the diffuser mounting hole 112, the insertion portion 122 and the inner wall of the diffuser mounting hole 112 are welded all around, thereby joining the diffuser portion 12 to the housing main body 11.

[0022] 1 , the rupture disc 13 is a plate-shaped member that separates the internal space of the housing body 11 from the internal space of the diffuser section 12. The internal space of the housing body 11 is separated from the internal space of the diffuser section 12 by the rupture disc 13, thereby maintaining the internal space of the diffuser section 12 at normal pressure. The rupture disc 13 is joined to the diffuser section 12 by having its peripheral edge welded all around to the stepped surface of the diffuser section 12.

[0023] [Accommodation Space] The accommodation space 10 is formed as a space surrounded by the housing body 11 and rupture disc 13 of the housing 1 and the igniter assembly 2. The gas generating agent 20 accommodated in the accommodation space 10 burns upon activation of the igniter 3, generating combustion gas. The gas generating agent 20 may be, for example, a solid gas generating agent with a relatively low combustion temperature. The combustion temperature of the gas generating agent 20 is, for example, 1000 to 1700°C. The gas generating agent 20 may be, for example, a single-hole cylindrical agent made of guanidine nitrate (41% by weight), basic copper nitrate (49% by weight), a binder, and an additive. The pressurized gas accommodated in the accommodation space 10 may be, for example, an inert gas such as argon or helium, or a mixture thereof. However, the gas generating agent 20 and the pressurized gas are not limited to those described above.

[0024] As shown in FIG. 1 , a holder 7 is disposed in the accommodation space 10 for holding the gas generating agent 20 near the igniter assembly 2. The holder 7 is a cylindrical member that extends vertically and has a closed top end, and is disposed so as to surround the igniter assembly 2 attached to the igniter attachment hole 111. This divides the accommodation space 10 into a combustion chamber 10a inside the holder 7 and a pressurized gas chamber 10b outside the holder 7. The gas generating agent 20 is disposed in the combustion chamber 10a formed around the igniter assembly 2. Note that a communication hole 71 large enough to prevent the gas generating agent 20 from passing through is formed in the holder 7, and the combustion chamber 10a and the pressurized gas chamber 10b communicate with each other via the communication hole 71. Therefore, pressurized gas is present in both the combustion chamber 10a and the pressurized gas chamber 10b. In other words, the entire accommodation space 10, including the combustion chamber 10a and the pressurized gas chamber 10b, is filled with pressurized gas, and the entire accommodation space 10 is in a pressurized state.

[0025] [Igniter Assembly] Figure 2 is a cross-sectional view showing the state near igniter assembly 2 before activation of gas generator 100 according to embodiment 1. As shown in Figure 2, igniter assembly 2 has an igniter 3, a collar member 4, a resin member 5, and a metal cover member 6.

[0026] [Igniter] As shown in FIG. 2 , the igniter 3 includes an ignition portion 31 and a pair of conductive pins 32. The ignition portion 31 has an ignition chamber 314 that accommodates an ignition charge. An ignition current for igniting the ignition charge accommodated in the ignition chamber 314 is supplied to the pair of conductive pins 32. The pair of conductive pins 32 is an example of a "conductive portion" according to the present disclosure. The igniter 3 is configured as an electric igniter. Specifically, when the ignition current supplied to the pair of conductive pins 32 activates the igniter 3, the ignition portion 31 splits open, releasing combustion products of the ignition charge. As shown in FIG. 2 , the igniter 3 is arranged such that the ignition portion 31 is located closer to the accommodation space 10 than the pair of conductive pins 32.

[0027] As shown in FIG. 2 , ignition unit 31 has a cup body 311, a metal header 312 (an example of a “closing member” according to the present disclosure), and a charge holder 313. Cup body 311 is formed in a cylindrical shape with a bottom and has a double structure in which an insulating outer cup 311b is superimposed on the outside of a metal inner cup 311a. The material of outer cup 311b is not particularly limited, but a resin material is exemplified. By interposing insulating outer cup 311b between the inner cup and cover member 6, current supplied to housing 1 due to a ground fault or the like is prevented from flowing to conductive pin 32 via cover member 6, inner cup 311a, or metal header 312 (i.e., accidental ignition of gas generator 100). Cup body 311 is configured to include a cylindrical peripheral wall portion 3111 and a lid wall portion 3112 that closes one end (upper end) of peripheral wall portion 3111. Lid wall portion 3112 is an example of a “cleavage portion” according to the present disclosure. The metal header 312 is a cylindrical metal member disposed inside the cup body 311 so as to close an opening formed at the other end (lower end) of the peripheral wall 3111. The metal header 312 is welded around its entire circumference to the inner wall of the peripheral wall 3111. As shown in FIG. 2 , the cup body 311 and the metal header 312 define an ignition chamber 314 that accommodates an ignition charge. The charge holder 313 is cylindrical. The charge holder 313 is disposed in the ignition chamber 314 facing the peripheral wall 3111 of the cup body 311 and in contact with the peripheral wall 3111 to surround the ignition charge. The provision of the charge holder 313 makes it easier, for example, to pressurize the ignition charge into the metal header 312. Furthermore, it is possible to prevent external pressure from changing the contact state between the ignition charge and a bridge wire 315 (described later) after assembly of the igniter 3.

[0028] The pair of conductive pins 32 extend downward from the ignition portion 31. One of the pair of conductive pins 32 is inserted into a through-hole of the metal header 312 and joined to the metal header 312 via an insulator 316. The other of the pair of conductive pins 32 is joined to the lower surface of the metal header 312. A connector (not shown) for supplying power from an external power source is connected to the pair of conductive pins 32.

[0029] The igniter 3 is activated by power supplied to a pair of conductive pins 32, 32 via a connector. A bridge wire 315, which is a resistor that electrically connects one of the conductive pins 32 and the metal header 312, is wired to the bottom of the ignition chamber 314. When current is supplied to the pair of conductive pins 32, 32, a current flows through the bridge wire 315, and the Joule heat generated in the bridge wire 315 burns the ignition charge in the ignition chamber 314. This increases the pressure within the ignition chamber 314, causing the cover wall 3112 of the cup body 311 to split open, and the combustion products of the ignition charge are released to the outside of the ignition chamber 314.

[0030] FIG. 3 is a top view of the inner cup 311a of the cup body 311 according to the first embodiment. FIG. 3 illustrates the upper end surface (closed end surface) of the inner cup 311a that constitutes the lid wall portion 3112 of the cup body 311. As shown in FIG. 3, a plurality of grooves 3113 extending radially from the center are formed in the upper end surface of the inner cup 311a. The plurality of grooves 3113 extend radially from the center of the upper end surface of the inner cup 311a. As shown in FIG. 3, eight grooves 3113 are formed at equal angular intervals in this example. However, the technology of the present disclosure is not limited to this. The portion of the upper end of the inner cup 311a where the grooves 3113 are formed is thinner than the other portions, making it more fragile and more susceptible to fracture than the other portions. This makes it easier for the lid wall portion 3112 to tear open when the igniter 3 is activated.

[0031] 2, the collar member 4 is a metallic tubular member that is disposed to surround the igniter 3 and supports the igniter 3 via the resin member 5. The collar member 4 has a first portion 41 that includes the lower end of the collar member 4, a second portion 42 that is connected to the upper end of the first portion 41 and has a smaller outer diameter than the first portion 41, and a third portion 43 that is connected to the upper end of the second portion 42, includes the upper end of the collar member 4, and has a smaller outer diameter than the second portion 42. As a result, a step is formed on the outer periphery of the collar member 4.

[0032] As shown in FIG. 2 , with the second portion 42 and the third portion 43 of the collar member 4 inserted into the igniter mounting hole 111 of the housing 1, the upper end surface of the first portion 41 is welded all around to the lower end surface of the housing main body 11, thereby joining the collar member 4 to the housing 1. Reference symbol W1 in FIG. 2 indicates the welded portion between the collar member 4 and the housing 1. Thus, with the igniter assembly 2 inserted into the igniter mounting hole 111 so as to close the igniter mounting hole 111, the collar member 4 is continuously welded (i.e., all around) to the housing 1 around its entire circumference, thereby attaching the igniter assembly 2 to the housing 1. Furthermore, with the third portion 43 of the collar member 4 fitted into an opening formed in the lower end of the holder 7, the outer peripheral surface of the second portion 42 is welded all around to the inner peripheral surface of the holder 7, thereby joining the holder 7 to the igniter assembly 2. Reference symbol W2 in FIG. 2 indicates the welded portion between the collar member 4 and the holder 7.

[0033] [Resin Member] As shown in FIG. 2 , the resin member 5 is a resin member that is disposed between the igniter 3 and the collar member 4 and integrally joins the igniter 3 and the collar member 4. The resin member 5 is provided so as to fill the annular gap formed between the igniter 3 and the collar member 4. At this time, the resin member 5 covers the igniter 3 so that the cover wall portion 3112, which is the portion that cleaves in the ignition portion 31, a portion of the peripheral wall portion 3111, and the tip ends of the pair of conductive pins 32, 32 are exposed from the resin member 5. The resin member 5 also covers the inner peripheral surface of the collar member 4 so that a connector insertion space 51, into which a power supply connector can be inserted, is formed inside the collar member 4. In this example, the resin member 5 also covers the upper end surface of the third portion 43 of the collar member 4 so that its outer peripheral surface is positioned flush with the outer peripheral surface of the third portion 43 of the collar member 4.

[0034] [Boundary] Here, the dotted line indicated by the symbol B1 in FIG. 2 indicates the boundary, which is the joint between the collar member 4 and the resin member 5. The boundary B1 is formed by the joint surfaces of the collar member 4 and the resin member 5. As shown in FIG. 2, the boundary B1 extends from the exterior to the interior of the housing 1. Here, the member formed by integrating the collar member 4 and the resin member 5 is referred to as the joined body 21. In this case, the end of the boundary B1 appears on the surface of the joined body 21 as the boundary line between the collar member 4 and the resin member 5. In FIG. 2, the end of the boundary line between the collar member 4 and the resin member 5 that appears inside the housing 1 is indicated by the symbol B11. The boundary line B11 is located on the outer circumferential surface of the joined body 21.

[0035] [Cover Member] The cover member 6 is a metal member that surrounds the ignition portion 31 and the resin member 5 so that the igniter 3 and the resin member 5 are sealed in the accommodation space 10 before the igniter 3 is activated, and that is configured to break open when the igniter 3 is activated. The metal material from which the cover member 6 is formed is not particularly limited, and examples include stainless steel, aluminum, and iron. As shown in FIG. 2 , the cover member 6 is formed in a generally cylindrical shape with a bottom, and has an axially extending portion 61, a radially extending portion 62, a peripheral wall facing portion 63, and a lid wall facing portion 64.

[0036] The axially extending portion 61 is formed in a cylindrical shape extending in the vertical direction. The axially extending portion 61 covers the outer peripheral surface of the third portion 43 of the collar member 4 and the outer peripheral surface of the resin member 5 across the boundary line B11 between the collar member 4 and the resin member 5, and is welded to the outer peripheral surface of the third portion 43 all around. Symbol W3 in FIG. 2 indicates the welded portion between the cover member 6 and the collar member 4. The cover member 6 and the collar member 4 are continuously welded all around at a position exposed to the accommodation space 10, and the welded portion W3 is exposed to pressurized gas. Therefore, the end of the boundary line B11 between the collar member 4 and the resin member 5 is not exposed to the accommodation space 10 and does not communicate with the accommodation space 10. The radially extending portion 62 extends radially inward from the upper end of the axially extending portion 61 and covers the upper end surface of the resin member 5. Circumferential wall opposing portion 63 is formed in a cylindrical shape extending upward from the inner end of radially extending portion 62, and covers the outer peripheral surface of peripheral wall portion 3111 of cup body 311. In other words, peripheral wall opposing portion 63 is disposed in a state of opposing and contacting peripheral wall portion 3111 of cup body 311. Note that peripheral wall opposing portion 63 does not have to be in contact with peripheral wall portion 3111 over the entire circumference, and a portion of peripheral wall opposing portion 63 may be in contact with peripheral wall portion 3111 in the circumferential direction. Before activation of gas generator 100, lid wall opposing portion 64 closes the upper end of peripheral wall opposing portion 63 and is formed in a dome shape (hemispherical shape) that is convex upward (toward storage space 10). Lid wall opposing portion 64 faces lid wall portion 3112 of cup body 311, and forms a predetermined space S1 between itself and lid wall portion 3112. The cover wall facing portion 64 is formed to have a uniform thickness overall.

[0037] When the igniter 3 is activated, the cover wall facing portion 64 is torn open by the pressure of the combustion products of the ignition charge released from the ignition portion 31 into the predetermined space S1, thereby opening the cover member 6. The cover wall facing portion 64 may have a groove formed therein to facilitate favorable rupture of the cover wall facing portion 64. This groove may be, for example, a groove extending radially from the top of the cover wall facing portion 64. Note that the cover member 6 itself does not need to be ruptured. Although no hole is formed in the cover member 6 according to this embodiment, for example, a through-hole may be formed in the cover member 6 and the through-hole may be blocked with a blocking member to form a sealed state. In this case, when the igniter 3 is activated, the blocking member may be torn open by the pressure of the combustion products.

[0038] As shown in FIG. 2 , cover member 6 is welded all around to collar member 4, so that before activation of igniter 3, igniter 3, resin member 5, and predetermined space S1 surrounded by cover member 6 are sealed from accommodating space 10. Therefore, predetermined space S1 is maintained at normal pressure. Furthermore, cover member 6 is welded all around to collar member 4 across boundary line B11 so that an end of boundary portion B1 between resin member 5 and collar member 4 is not exposed to accommodating space 10. Therefore, before activation of igniter 3, boundary portion B1 is sealed from accommodating space 10. This prevents moisture from entering accommodating space 10 from outside gas generator 100 through boundary portion B1 and prevents pressurized gas from leaking from accommodating space 10 to outside gas generator 100 through boundary portion B1. In other words, fluids (moisture and gas) are prevented from flowing into or out of accommodating space 10 via boundary portion B1. Furthermore, since the igniter 3 and the resin member 5 are also sealed with respect to the accommodating space 10 as described above, the inflow and outflow of fluid through the boundary between the igniter 3 and the resin member 5 is also prevented. For example, when the igniter 3 and the collar member 4 are integrated with each other by the resin member 5 formed by injection molding, there is a possibility that a gap will be generated at the boundary B1 between the resin member 5 and the collar member 4 or at the boundary between the igniter 3 and the resin member 5 due to shrinkage of the resin during hardening. Even when such a gap is generated, the gas generator 100 can prevent the inflow and outflow of fluid into and out of the accommodating space 10 through the gap. Furthermore, in the gas generator 100 according to the present embodiment, the collar member 4 is welded to the housing 1 all around, so the inflow and outflow of fluid through the boundary between the housing 1 and the collar member 4 is also prevented. As a result, in the gas generator 100 according to the present embodiment, the accommodating space 10 is maintained airtight from the outside of the gas generator 100 before the igniter 3 is activated.

[0039] Furthermore, when accommodation space 10 is filled with pressurized gas as in this example, cover member 6 functions as a protector for protecting igniter 3 from the effects of high pressure. If cover member 6 were not present and ignition section 31 of igniter 3 were exposed to pressurized gas, there is a risk that cup body 311 would deform, causing a deterioration in the state of contact between bridge wire 315 arranged in ignition chamber 314 and the ignition charge. In such cases, a situation may arise in which the desired ignition performance of igniter 3 cannot be obtained, or an external diagnostic circuit may detect an error and cause igniter 3 to fail to operate. By providing cover member 6, gas generator 100 according to this embodiment can prevent such situations.

[0040] Furthermore, as will be described later, predetermined space S1 is a space that makes it easier to cleave lid wall portion 3112 of cup body 311 when igniter 3 is activated. In gas generator 100 according to the present embodiment, lid wall opposing portion 64 of cover member 6, which forms predetermined space S1 between itself and lid wall portion 3112, is formed in a rounded dome shape, thereby imparting strength (pressure resistance) against pressurized gas to lid wall opposing portion 64. Therefore, it is possible to suppress deformation of lid wall opposing portion 64 due to pressurized gas before activation of igniter 3. Furthermore, it is possible to thin lid wall opposing portion 64 so that lid wall opposing portion 64 is easier to cleave when igniter 3 is activated.

[0041] Here, when comparing the ease of deformation due to the pressurized gas for each portion of cover member 6, circumferential wall facing portion 63 formed in a cylindrical shape tends to be more susceptible to deformation than other portions. In contrast, in gas generator 100 according to the present embodiment, circumferential wall facing portion 63 is disposed facing circumferential wall portion 3111 of cup body 311 and in contact with circumferential wall portion 3111. Furthermore, in ignition chamber 314, tubular charge holder 313 is disposed facing circumferential wall portion 3111 and in contact with circumferential wall portion 3111. As a result, circumferential wall facing portion 63 of cover member 6 is supported by circumferential wall portion 3111 of cup body 311 and charge holder 313 with respect to the pressurized gas. This makes it possible to suppress deformation of circumferential wall facing portion 63 due to the pressurized gas before activation of igniter 3.

[0042] 2, the cover member 6 is in a state where all parts thereof except for the lid wall facing portion 64 are in contact with and supported by either the igniter 3, the collar member 4, or the resin member 5. Therefore, deformation of the cover member 6 due to the pressurized gas before the activation of the igniter 3 can be more suitably suppressed.

[0043] In the technology disclosed herein, the lid wall-facing portion of the cover member does not have to be dome-shaped, and the lid wall-facing portion may contact the lid wall portion of the cup body. In other words, the lid wall-facing portion may cover the lid wall portion so that the entire cover member is in contact with either the igniter, the collar member, or the resin member, and no space may be provided between the lid wall portion and the cover member. Furthermore, in the technology disclosed herein, the peripheral wall-facing portion of the cover member does not have to contact the peripheral wall portion of the cup body. The cover member may not contact the collar member except for the welded portion with the collar member. Furthermore, the cover member 6 may not have a peripheral wall-facing portion 63, and a dome-shaped lid wall-facing portion 64 may be connected to the radially inner end of the radially extending portion 62.

[0044] [Operation] Next, the operation of gas generator 100 according to embodiment 1 will be described. In the state in which pre-activation gas generator 100 shown in Figures 1 and 2 is assembled to a vehicle, a connector (not shown) inserted into connector insertion space 51 is connected to a pair of conductive pins 32, 32 of igniter 3, and power can be supplied to igniter 3. In this state, when a sensor (not shown) mounted on the vehicle detects an impact, power from an external power supply (not shown) is supplied to the pair of conductive pins 32, 32 via the connector, thereby activating igniter 3 and causing the ignition charge in ignition chamber 314 to combust.

[0045] Figure 4 is a cross-sectional view showing the state of the vicinity of igniter assembly 2 when gas generator 100 according to embodiment 1 is activated and ignition portion 31 is ruptured. When the pressure in ignition chamber 314 increases as the ignition charge burns, lid wall portion 3112 of cup body 311 is ruptured, and combustion products of the ignition charge are released from ignition portion 31 into predetermined space S1, as shown in Figure 4. At this time, because predetermined space S1 is secured between lid wall portion 3112 and cover member 6, rupture of lid wall portion 3112 is prevented by cover member 6. This makes it easier for lid wall portion 3112 to rupture.

[0046] When the pressure in predetermined space S1 increases due to the combustion products released from ignition portion 31, lid wall facing portion 64 of cover member 6 is cleaved, and the combustion products of the ignition charge are released into combustion chamber 10a of accommodating space 10. Here, as described above, a plurality of grooves 3113 extending radially from the center are formed in the upper end surface of inner cup 311a constituting lid wall portion 3112 of cup body 311. Therefore, lid wall portion 3112 cleaves in a petal-like manner from the center. At this time, the flow of combustion products released from ignition portion 31 depends on the cleavage angle θ of the cleavage pieces of lid wall portion 3112. The cleavage angle θ can be defined as the angle of the cleavage pieces with respect to a plane perpendicular to the axial direction of peripheral wall portion 3111, as shown in FIG. 4 . In gas generator 100 according to the present embodiment, a plurality of grooves 3113 are formed such that the cleavage angle θ of the cleavage pieces of lid wall portion 3112 is equal to or less than a predetermined value. Therefore, as shown in Fig. 4, the combustion products of the ignition charge are released in a concentrated manner toward cover member 6 (more specifically, lid wall opposing portion 64). This makes it easier for cover member 6 to split open. Furthermore, in gas generator 100 according to the present embodiment, in order to hasten the pressure increase in predetermined space S1, the volume of predetermined space S1 is set to be equal to or less than a predetermined value. This also makes it easier for cover member 6 to split open.

[0047] FIG. 5 is a cross-sectional view showing the state near the igniter assembly 2 when the gas generator 100 according to the first embodiment is activated and the cover member 6 is ruptured. The combustion products of the ignition charge are released into the combustion chamber 10a of the accommodating space 10, igniting the gas generating agent 20 disposed in the combustion chamber 10a. The combustion gas of the gas generating agent 20 flows into the pressurized gas chamber 10b via a communication hole 71 formed in the holder 7. Furthermore, when the pressure in the accommodating space 10 increases with the generation of combustion gas, the rupture disk 13 shown in FIG. 1 is ruptured. As a result, the combustion gas generated by the combustion of the gas generating agent and the pressurized gas contained in the accommodating space 10 are discharged to the outside of the gas generator 100 through the gas discharge hole 14 of the diffuser portion 12. As a result, the airbag inflates, protecting the vehicle occupant from an impact.

[0048] [Effect] As described above, gas generator 100 according to the first embodiment includes housing 1 in which igniter mounting hole 111 is formed, and igniter assembly 2 that is attached to housing 1 so as to close igniter mounting hole 111 and that, together with housing 1, defines accommodation space 10 in which a gas source is accommodated. Igniter assembly 2 has igniter 3, a metal collar member 4, a resin member 5 made of resin, and a metal cover member 6. Igniter 3 includes ignition portion 31 formed with ignition chamber 314 in which ignition charge is accommodated, and a pair of conductive pins 32, 32 to which an ignition current for igniting the ignition charge is supplied, and is arranged such that ignition portion 31 is located closer to the interior of accommodation space 10 than the pair of conductive pins 32, 32. Igniter 3 is also configured so that, when activated by an ignition current supplied to the pair of conductive pins 32, 32, 31 cleaves open, releasing combustion products of the ignition charge. Collar member 4 is formed in a cylindrical shape and is inserted into igniter mounting hole 111 so as to surround igniter 3. Resin member 5 is disposed between igniter 3 and collar member 4 and integrally joins igniter 3 and collar member 4 with cover wall portion 3112, which is the portion that cleaves in ignition portion 31, and a pair of conductive pins 32, 32 exposed from resin member 5. Cover member 6 surrounds ignition portion 31 and resin member 5 so that igniter 3 and resin member 5 are sealed from accommodation space 10, and is configured to cleave when igniter 3 is activated. Cover member 6 is welded all around to collar member 4 across boundary line B11 between resin member 5 and collar member 4. Gas generator 100 according to embodiment 1 configured in this manner can improve the airtightness of accommodation space 10 in which the gas source is accommodated.

[0049] Furthermore, collar member 4 of gas generator 100 according to the first embodiment is welded to housing 1 along its entire periphery. This enables the airtightness of accommodating space 10 to be further improved.

[0050] Moreover, cover member 6 of gas generator 100 according to the first embodiment is formed so that a predetermined space S1 is secured between cover member 6 and lid wall portion 3112 that cleaves open at ignition section 31. This makes it possible to make lid wall portion 3112 easier to cleave open.

[0051] Moreover, in gas generator 100 according to the first embodiment, gas generating agent 20 and pressurized gas are contained as a gas source in accommodating space 10. According to gas generator 100 in which the airtightness of accommodating space 10 is improved as described above, leakage of pressurized gas to the outside of gas generator 100 can be suppressed.

[0052] Furthermore, ignition unit 31 of gas generator 100 according to embodiment 1 has a cup body 311 including a cylindrical peripheral wall portion 3111 and a lid wall portion 3112 closing one end of peripheral wall portion 3111. Furthermore, ignition unit 31 has a metal header 312 that is arranged to close an opening formed in the other end of peripheral wall portion 3111 and that, together with cup body 311, defines ignition chamber 314. Furthermore, ignition unit 31 is configured so that, when igniter 3 is activated, lid wall portion 3112 is ruptured, thereby releasing combustion products of the ignition charge to the outside of ignition chamber 314. Furthermore, cover member 6 has a cylindrical peripheral wall opposing portion 63 that is arranged facing and in contact with peripheral wall portion 3111 of cup body 311, and a dome-shaped lid wall opposing portion 64 that faces lid wall portion 3112 of cup body 311 and is formed to be convex toward accommodation space 10. As a result, the peripheral wall opposing portion 63 is supported by the peripheral wall portion 3111 of the cup body 311 and the pressure resistance of the lid wall opposing portion 64 is improved, thereby suppressing deformation of the cover member 6 due to pressurized gas before the igniter 3 is activated.

[0053] Furthermore, ignition section 31 of gas generator 100 according to embodiment 1 further has a cylindrical charge holder 313 that is arranged in ignition chamber 314 to surround the ignition charge while facing and in contact with peripheral wall section 3111 of cup body 311. With this, peripheral wall facing section 63 of cover member 6 is supported by peripheral wall section 3111 of cup body 311 and charge holder 313, and deformation of peripheral wall facing section 63 can be more suitably suppressed.

[0054] Furthermore, in gas generator 100 according to the first embodiment, when igniter 3 is activated, lid wall portion 3112 of ignition portion 31 is cleaved so that the combustion products of the ignition charge are emitted in a concentrated manner toward cover member 6. This makes it possible to make cover member 6 easier to cleave.

[0055] [Modifications] Below, a description will be given of a gas generator according to a modification of embodiment 1. In the description of the modification, the differences from gas generator 100 described in Figures 1 to 5 will be mainly described, and detailed description of the points that are the same as those of gas generator 100 will be omitted.

[0056] [Modification 1] Fig. 6 is a cross-sectional view showing the state in the vicinity of igniter assembly 2 before activation of gas generator 100A according to modification 1 of Embodiment 1. Moreover, Fig. 7 is a cross-sectional view showing the state in the vicinity of igniter assembly 2 when gas generator 100A according to modification 1 of Embodiment 1 is activated and cover member 6A is torn open. As shown in Fig. 7, in gas generator 100A according to modification 1 of Embodiment 1, when igniter 3 is activated, lid wall portion 3112 of cup body 311 is torn open so as to come into contact with cover member 6A. As shown in Figs. 6 and 7, cover member 6A according to modification 1 is formed so that a predetermined space S1 is secured between cover wall portion 3112 and cover member 6A before igniter 3 is activated, and yet a torn piece of cover wall portion 3112 comes into contact with cover member 6A when igniter 3 is activated. When the igniter 3 is activated, the tear-off piece of the lid wall portion 3112 of the cup body 311 comes into contact with the cover member 6A, causing stress to be concentrated on the cover member 6A (the portion where the tear-off piece comes into contact). This makes it easier to tear off the cover member 6A.

[0057] [Modification 2] Fig. 8 is a cross-sectional view showing the state near igniter assembly 2 before activation of gas generator 100B according to Modification 2 of Embodiment 1. As shown in Fig. 8, in gas generator 100B according to Modification 2, resin member 5 covers the inner circumferential surface of collar member 4 such that its upper end surface is located on the same plane as the upper end surface of third portion 43 of collar member 4. Therefore, the end of boundary line B11 between collar member 4 and resin member 5 that appears inside housing 1 is located on the upper end surface of joined body 21 of collar member 4 and resin member 5. Furthermore, cover member 6B according to Modification 2 does not have the above-mentioned axially extending portion 61. Radially extending portion 62 of cover member 6B covers the upper end surfaces of third portion 43 of collar member 4 and the upper end surface of resin member 5 so as to straddle boundary line B11 between collar member 4 and resin member 5, and is continuously welded around the entire circumference to the upper end surface of third portion 43. In the gas generator 100B according to variant example 2, the cover member 6B is welded all around to the collar member 4 across the boundary line B11 between the resin member 5 and the collar member 4, thereby improving the airtightness of the storage space 10.

[0058] <Embodiment 2> A gas generator 100C according to Embodiment 2 will be described below. Fig. 9 is a cross-sectional view showing a state before activation of gas generator 100C according to Embodiment 2. Fig. 9 shows a cross-section along the axial direction of housing 1C. Gas generator 100C according to Embodiment 2 is configured as a so-called pyro-type gas generator that uses only a gas generating agent as the gas source. In the description of Embodiment 2, differences from gas generator 100 according to Embodiment 1 described in Figs. 1 to 5 will be mainly described, and a detailed description of the similarities between gas generator 100 and gas generator 100 will be omitted.

[0059] [Configuration] As shown in Fig. 9 , gas generator 100C according to the second embodiment includes a housing 1C, an igniter assembly 2, a filter 8, and an inner cylindrical member 9. Note that gas generator 100C according to the second embodiment includes the igniter assembly 2 shown in Fig. 2 , but may instead include the igniter assembly 2 shown in Fig. 8 .

[0060] 9, the housing 1C according to the second embodiment is formed into a short cylindrical shape with both axial ends closed by joining an upper shell 15 and a lower shell 16, each of which is made of metal and has a cylindrical shape with a bottom, with the open ends facing each other. However, the configuration of the upper shell 15 and the lower shell 16 is not limited to this, and any known shell may be used as appropriate.

[0061] 9 , the upper shell 15 has a cylindrical upper tube portion 151, a top plate portion 152 closing the upper end of the upper tube portion 151, and a flange-like joint portion 153 extending radially outward from the lower end of the upper tube portion 151. The lower shell 16 has a cylindrical lower tube portion 161, a bottom plate portion 162 closing the lower end of the lower tube portion 161, and a flange-like joint portion 163 extending radially outward from the upper end of the lower tube portion 161. The joint portion 153 of the upper shell 15 and the joint portion 163 of the lower shell 16 are overlapped and joined by welding or the like to form the housing 1C.

[0062] A plurality of gas discharge holes 17 communicating the inside and outside of housing 1C are formed in a row along the circumferential direction in upper cylindrical portion 151 of upper shell 15. Before activation of gas generator 100C, gas discharge holes 17 are closed by a closing member such as sealing tape (not shown).

[0063] Furthermore, an igniter mounting hole 18 for mounting the igniter assembly 2 is formed in the bottom plate portion 162 of the lower shell 16. The igniter assembly 2 is attached to the housing 1C by inserting the collar member 4 into the igniter mounting hole 18 so as to close the igniter mounting hole 18 and then welding the collar member 4 to the housing 1C (more specifically, the inner wall of the igniter mounting hole 18) all around.

[0064] 9 , filter 8 is a cylindrical member having multiple holes formed therein, and is disposed between igniter assembly 2 and gas discharge hole 17 with its upper end supported by top plate portion 152 of upper shell 15 and its lower end supported by bottom plate portion 162 of lower shell 16. As a result, an accommodating space 10C for accommodating a gas source is formed between housing 1C, filter 8, and igniter assembly 2. More specifically, accommodating space 10C is formed as a space surrounded by top plate portion 152 of upper shell 15, bottom plate portion 162 of lower shell 16, filter 8, and igniter assembly 2.

[0065] As shown in FIG. 9 , the inner cylindrical member 9 is a bottomed cylindrical member that extends vertically and has a closed upper end. The inner cylindrical member 9 is disposed to surround the igniter assembly 2 attached to the igniter attachment hole 18. The collar member 4 of the igniter assembly 2 is fitted into an opening formed at the lower end of the inner cylindrical member 9, and the collar member 4 and the inner cylindrical member 9 are welded all around, thereby joining the inner cylindrical member 9 to the igniter assembly 2. The inner cylindrical member 9 divides the accommodation space 10C into a first combustion chamber 101 inside the inner cylindrical member 9 and a second combustion chamber 102 outside the inner cylindrical member 9. The inner cylindrical member 9 also has a plurality of communication holes 91 that communicate between its internal space (i.e., the first combustion chamber 101) and its external space (i.e., the second combustion chamber 102). The communication holes 91 are closed by a blocking member such as sealing tape (not shown) before the igniter 3 is activated.

[0066] The first combustion chamber 101 accommodates a first gas generating agent 30 as a gas source, and the second combustion chamber 102 accommodates a second gas generating agent 40 as a gas source. The first gas generating agent 30 burns upon activation of the igniter 3, generating combustion gas. The first gas generating agent 30 functions as a so-called transfer charge for igniting the second gas generating agent 40. The second gas generating agent 40 is ignited by combustion gas from the first gas generating agent 30 (transfer charge) that is combusted upon activation of the igniter 3, generating combustion gas. The first gas generating agent 30 and the second gas generating agent 40 may be the same as the gas generating agent 20 according to the first embodiment described above. However, the first gas generating agent 30 and the second gas generating agent 40 are not limited to those described above. Furthermore, the first gas generating agent 30 and the second gas generating agent 40 may be gas generating agents of the same type, shape, and dimensions, or may be gas generating agents of different types, shapes, and dimensions.

[0067] The filter 8 is configured to allow the combustion gas to pass through, and the combustion gas is cooled as it passes through the filter 8. At this time, the filter 8 filters the combustion gas by collecting combustion residue of the combustion gas.

[0068] [Operation] Next, the operation of the gas generator 100C according to the second embodiment will be described. The operation of the igniter 3 is the same as in the first embodiment, and therefore a description thereof will be omitted. When the igniter 3 is activated, the ignition portion 31 ruptures, releasing combustion products of the ignition charge. The combustion products released from the ignition portion 31 rupture the cover member 6, and the combustion products are released into the first combustion chamber 101 of the accommodation space 10. This causes the first gas generating agent 30 (transfer charge) accommodated in the first combustion chamber 101 to combust, generating combustion gas. The combustion gas of the first gas generating agent 30 breaks the sealing tape that has been closing the communication hole 91, and is released from the communication hole 91 into the second combustion chamber 102. The combustion gas of the first gas generating agent 30 then ignites the second gas generating agent 40, generating combustion gas of the second gas generating agent 40. The combustion gas in the accommodation space 10C is cooled and filtered by passing through the filter 8, and then breaks the sealing tape that has been closing the gas discharge hole 17, and is released to the outside of the gas generator 100C. This causes the airbag to inflate, protecting the vehicle occupants from impact.

[0069] [Actions and Effects] Gas generator 100C according to embodiment 2 also achieves the same effects as embodiment 1. That is, because cover member 6 is welded all around to collar member 4 across the boundary line between resin member 5 and collar member 4, it is possible to prevent moisture from entering accommodating space 10C through the boundary between resin member 5 and collar member 4 or the boundary between igniter 3 and resin member 5. As a result, gas generator 100C according to embodiment 2 can improve the airtightness of accommodating space 10C.

[0070] <Others> Although embodiments of the technology according to the present disclosure have been described above, each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. Furthermore, in the above-described embodiments, examples have been described in which the technology according to the present disclosure is applied to a hybrid-type gas generator or a pyrotechnic-type gas generator, but the technology according to the present disclosure may also be applied to a so-called stored-type gas generator that uses only pressurized gas as a gas source. For example, the technology according to the present disclosure may be applied to a gas generator that releases gas by rupturing a rupture disc using a shock wave, as disclosed in JP-A-2003-520153.

[0071] DESCRIPTION OF SYMBOLS 1... Housing (an example of a container) 111... Igniter mounting hole 2... Igniter assembly 3... Igniter 4... Collar member 5... Resin member 6... Cover member 10... Storage space 20... Gas generating agent (an example of a gas source) 100... Gas generator

Claims

1. A housing having an igniter mounting hole; an igniter assembly attached to the housing so as to close the igniter mounting hole, the igniter assembly defining, together with the housing, an accommodation space in which a gas source is accommodated; The igniter assembly includes: An igniter including an ignition unit having an ignition chamber in which an ignition charge is accommodated, and a conductive unit to which an ignition current for igniting the ignition charge is supplied, the ignition unit being disposed so as to be located closer to the interior of the accommodation space than the conductive unit, and configured so that the ignition unit is cleaved by being activated by the ignition current supplied to the conductive unit to release a combustion product of the ignition charge; a metallic collar member formed in a cylindrical shape and inserted into the igniter mounting hole so as to surround the igniter; a resin member made of resin and arranged between the igniter and the collar member, the resin member integrally joining the igniter and the collar member in a state in which at least the conductive portion is exposed from the resin member; a metal cover member that surrounds the ignition portion and the resin member so that the igniter and the resin member are sealed in the accommodation space and is configured to be torn when the igniter is activated, The cover member is welded to the collar member all around across the boundary line between the resin member and the collar member. Gas generator.

2. The storage space contains a gas generating agent and a pressurized gas as the gas source.

2. The gas generator according to claim 1.

3. The cover member is formed so that a space is secured between the cover member and a cleavable portion which is a portion that cleaves in the ignition portion.

2. The gas generator according to claim 1.

4. The ignition unit has a cup body including a cylindrical peripheral wall portion and a cover wall portion that closes one end of the peripheral wall portion and is formed as the cleavage portion, and a closing member that is arranged to close an opening formed at the other end of the peripheral wall portion and that defines the ignition chamber together with the cup body, and when the igniter is activated, Then, the cover wall portion is cleaved to release a combustion product of the ignition charge to the outside of the ignition chamber, The cover member has a cylindrical peripheral wall facing portion disposed in a state of facing and contacting the peripheral wall portion, and a dome-shaped lid wall facing portion formed to face the lid wall portion and to be convex toward the storage space side.

4. The gas generator according to claim 3.

5. The ignition section has a cup body including a cylindrical peripheral wall portion and a lid wall portion closing one end of the peripheral wall portion and formed as the cleavage portion, and a closing member arranged to close an opening formed at the other end of the peripheral wall portion and defining the ignition chamber together with the cup body, and is configured to release a combustion product of the ignition charge by cleaving the lid wall portion when the igniter is activated, The ignition unit further includes a cylindrical charge holder disposed in the ignition chamber so as to surround the ignition charge while facing the peripheral wall portion and in contact with the peripheral wall portion.

4. The gas generator according to claim 3.

6. The ignition section has a cup body including a cylindrical peripheral wall portion and a lid wall portion closing one end of the peripheral wall portion and formed as the cleavage portion, and a closing member arranged to close an opening formed at the other end of the peripheral wall portion and defining the ignition chamber together with the cup body, and is configured to release a combustion product of the ignition charge by cleaving the lid wall portion when the igniter is activated, The cover wall portion is cleaved so that the combustion products are concentrated and radiated toward the cover member, thereby cleaving the cover member.

4. The gas generator according to claim 3.

7. The ignition section has a cup body including a cylindrical peripheral wall portion and a lid wall portion closing one end of the peripheral wall portion and formed as the cleavage portion, and a closing member arranged to close an opening formed at the other end of the peripheral wall portion and defining the ignition chamber together with the cup body, and is configured to release a combustion product of the ignition charge by cleaving the lid wall portion when the igniter is activated, The cover wall portion is cleaved so as to come into contact with the cover member, thereby cleaving the cover member.

4. The gas generator according to claim 3.

8. The collar member is welded to the housing.

2. The gas generator according to claim 1.

9. A housing defining an accommodation space therein; an igniter assembly attached to the housing; The igniter assembly includes: An igniter having an ignition portion located on the inner side of the accommodation space; A metallic collar member formed in a cylindrical shape and surrounding the igniter; a resin member made of resin and arranged between the igniter and the collar member; a metal cover member that surrounds the ignition portion and the resin member so that the igniter and the resin member are sealed from the storage space, has a rounded dome shape formed to be convex toward the storage space, and is welded all around to the collar member across the boundary line between the resin member and the collar member; Gas generator.

10. The cover member is configured such that the igniter and the resin member are not in the housing before the igniter is activated. The sealing member is configured to surround the ignition portion and the resin member so as to be sealed against the space and to be ruptured when the igniter is activated, The storage space contains a gas generating agent and a pressurized gas as a gas source.

10. The gas generator according to claim 9.

11. The cover member is formed so as to secure a space between the cover member and the ignition portion.

10. The gas generator according to claim 9.

12. The ignition portion has a cup body including a cylindrical peripheral wall portion and a lid wall portion closing one end of the peripheral wall portion and formed as a cleavage portion, and a closure member arranged to close an opening formed in the other end of the peripheral wall portion and defining an ignition chamber together with the cup body, and is configured such that when the igniter is activated, the lid wall portion cleaves to release combustion products of the ignition charge, The ignition unit further includes a cylindrical charge holder disposed in the ignition chamber so as to surround the ignition charge while facing the peripheral wall portion and in contact with the peripheral wall portion.

12. The gas generator according to claim 11.

13. The resin member covers an inner peripheral surface of the collar member so that an upper end surface of the resin member is positioned on the same plane as an upper end surface of the collar member, the cover member has a radially extending portion, the radially extending portion covers an upper end surface of the collar member and an upper end surface of the resin member so as to straddle a boundary line between the collar member and the resin member, and is continuously welded to the upper end surface of the collar member around the entire periphery.

10. The gas generator according to claim 9.

14. The resin member covers an upper end surface of the collar member such that an outer circumferential surface of the resin member is positioned on the same plane as an outer circumferential surface of the collar member, The axially extending portion formed in the cover member in a cylindrical shape extending in the vertical direction covers the outer peripheral surface of the collar member and the outer peripheral surface of the resin member so as to straddle the boundary line between the collar member and the resin member, and is welded to the outer peripheral surface of the collar member in its entirety.

10. The gas generator according to claim 9.

15. The cover member is formed in a bottomed cylindrical shape, has a peripheral wall facing portion and a lid wall facing portion, and the lid wall facing portion is formed to have a uniform thickness overall.

10. The gas generator according to claim 9.