Gas generator

Abstract

The present invention enhances igniting performance of a gas generating agent in a gas generator. This gas generator includes an igniter assembly that discharges a combustion product and that includes: an igniter main body that is provided with an igniter cup that stores an ignition powder and also cleaves due to the combustion product produced as a result of combustion of the ignition powder and a conductive pin that supplies current for igniting the ignition powder; a collar part that holds the igniter main body; and a holding part that is interposed between the igniter main body and the collar part and that fixes the igniter main body to the collar part. The gas generator also includes: a cylindrical housing that includes a combustion chamber that stores a gas generating agent and in which a gas discharge hole is formed for discharging combustion gas produced as a result of combustion of the gas generating agent; and a cylindrical elastic member that is disposed in the housing between the igniter assembly and the gas generating agent so that an axial direction thereof is arranged in a direction identical to the housing, the elastic member including, on an inner circumference thereof, a regulating part that regulates a direction in which the cleaved igniter cup expands.

Description

[Technical Field]

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

[0002] Conventionally, a gas generator has been proposed that includes a long, substantially cylindrical housing, a holder attached to one open end of the housing, and a closing member attached to the other end of the housing so as to close the other open end of the housing (for example, Patent Document 1). In this technology, an igniter is disposed at one axial end of the housing as a means for igniting the gas generating agent. In addition, the coil spring has a large-diameter portion that is densely wound in a spiral shape along the inner wall of the housing and a reduced-diameter portion that is loosely wound with a predetermined gap between them, and one end abuts against the holder and the other end abuts against at least a portion of the periphery of the through-hole on one end side of the gas generating agent, so as to apply an elastic force to the gas generating agent. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-7456 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the above-described technology, the gas generating agent can be fixed in place by applying an elastic force to the gas generating agent using a coil spring. However, if the coil spring increases the distance between the igniter and the gas generating agent, the direction in which the combustion products generated by the igniter are released may be dispersed, and the combustion products may not reach the gas generating agent efficiently. For example, if the combustion products released by the igniter are dispersed, some of them may collide with the inner wall of the housing.

[0005] The technique of the present disclosure aims to improve the ignition performance of a gas generating agent in a gas generator. [Means for solving the problem]

[0006] (Aspect 1) The gas generator according to the present disclosure comprises: an igniter body including an igniter cup that houses an ignition charge and is cleaved by combustion products produced by combustion of the ignition charge, and a conductive pin that supplies current to ignite the ignition charge; an igniter assembly that has a collar portion that holds the igniter body, and a holding portion that is interposed between the igniter body and the collar portion and fixes the igniter body to the collar portion, and that releases the combustion products; a cylindrical housing that has a combustion chamber that houses a gas generating agent and is formed with a gas discharge hole that discharges combustion gas produced by combustion of the gas generating agent; and a cylindrical elastic member that is arranged within the housing between the igniter assembly and the gas generating agent, with its axial direction aligned with the axial direction of the housing, and that has a restricting portion on its inner periphery that restricts the direction in which the cleaved igniter cup deploys.

[0007] In this way, the direction in which the igniter cup deploys is restricted by the restricting portion, and the direction in which the combustion products are released when the igniter main body is activated is guided by the deployed igniter cup. In other words, the direction in which the combustion products are released can be controlled toward the gas generating agent, thereby improving the ignition performance of the gas generating agent in the gas generator.

[0008] (Aspect 2) In addition, in the first aspect, the igniter cup may have a portion of its periphery defined by a notch formed on the cleavage surface facing the combustion chamber for guiding the rupture position, and may have a deployment portion that deploys while the other portion of the periphery is connected to the igniter cup during combustion of the ignition charge, and the restricting portion may be provided at a position that contacts the deployed deployment portion. Specifically, such a configuration may be adopted.

[0009] (Aspect 3) In addition, in the first or second aspect, the restricting portion may be a reduced diameter portion where the inner diameter of the elastic member is smallest. (Aspect 4) In addition, in the third aspect, the elastic member may be configured so that its diameter decreases from the igniter assembly side toward the reduced diameter portion. Specifically, the restricting portion can be formed by such a configuration.

[0010] (Aspect 5) In addition, in the third or fourth aspect, the elastic member may be configured to expand in diameter from the reduced diameter portion toward the other end of the housing, thereby allowing the combustion products to be diffused at a desired angle from the reduced diameter portion toward the gas generating agent.

[0011] (Aspect 6) In any of the first to fifth aspects, the elastic member may be configured so that the igniter assembly side fits into the collar portion or the holding portion. Specifically, the elastic member can be connected to the gas generator in this manner.

[0012] (Aspect 7) In any of aspects 1 to 6, the elastic member may have a lower elastic modulus on the gas generating agent side than on the igniter assembly side, relative to the restriction portion. In this way, the distance from the igniter assembly connected to one end of the housing to the restriction portion is less likely to change, and the restriction portion can be disposed at a pre-designed position relative to the igniter assembly.

[0013] (Aspect 8) In any of the first to seventh aspects, the elastic member may be a coil spring. Specifically, such a configuration can be adopted.

[0014] (Aspect 9) The elastic member may have a through-hole at its end on the gas generating agent side that is large enough to allow the combustion products to pass through but not the gas generating agent, and urge the gas generating agent toward the opposite side from the igniter assembly. In this way, the elastic member can allow the combustion products of the igniter body to pass through while retaining the gas generating agent on the combustion chamber side without passing through.

[0015] The contents described in the means for solving the problems can be combined as much as possible within the scope of the problems and technical ideas of this disclosure. [Effects of the Invention]

[0016] According to the present disclosure, it is possible to improve the ignition performance of the gas generating agent in the gas generator. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic axial cross-sectional view showing an example of a gas generator. [Figure 2] FIG. 2 is a schematic cross-sectional view for explaining the configuration of the igniter assembly and its surroundings. [Figure 3] FIG. 3 is a schematic view of the top surface of the cup body as viewed from the housing side in the axial direction of the housing. [Figure 4] FIG. 4 is a schematic cross-sectional view of the igniter assembly and its surroundings, showing an example of a state in which the igniter main body is activated. [Figure 5] FIG. 5 is a diagram for explaining the length from the igniter main body to the reduced diameter portion. [Figure 6] FIG. 6 is a schematic cross-sectional view of the periphery of an igniter assembly according to a first modified example. [Figure 7] FIG. 7 is a schematic cross-sectional view of the periphery of an igniter assembly according to a second modified example. [Figure 8] FIG. 8 is a schematic cross-sectional view of the periphery of an igniter assembly according to a third modified example. [Figure 9] FIG. 9 is a schematic cross-sectional view of the periphery of an igniter assembly according to a fourth modified example. [Figure 10] FIG. 10 is a schematic cross-sectional view of the periphery of an igniter assembly according to a fifth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0018] 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 merely 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 disclosure. The present disclosure is not limited by the embodiments, but is limited only by the scope of the claims.

[0019] <Embodiment> Fig. 1 is a schematic axial cross-sectional view showing an example of a gas generator. Fig. 2 is a schematic cross-sectional view for explaining an igniter assembly and its surrounding configuration. Gas generator 1 is a cylindrical device that burns a gas generating agent contained therein and discharges combustion gas to the outside, and can be used, for example, to inflate an airbag. Gas generator 1 in Fig. 1 includes a cylindrical housing 2, an igniter assembly 3 attached to one axial end of housing 2, and a diffuser portion 4 formed at the other end of housing 2.

[0020] The igniter assembly 3 is a device that is ignited by an ignition current and is used in existing gas generators. For example, the igniter assembly 3 includes an igniter body 31 that is ignited by receiving an external current, a metal collar portion 32, and a resin retaining portion 33 that secures the igniter body 31 to the collar portion 32. The collar portion 32 is a cylindrical metal member. The collar portion 32 is attached to an opening at one axial end of the housing 2 by, for example, full-circumference welding. The collar portion 32 retains the igniter body 31 inside the collar portion 32 via the retaining portion 33. The retaining portion 33 is interposed between the igniter body 31 and the collar portion 32 by injection molding and secures the igniter body 31 to the collar portion 32. Note that the inner circumferential surface of the collar portion 32 that comes into contact with the retaining portion 33 may be provided with irregularities to prevent circumferential rotation of the igniter body 31 and the collar portion 32.

[0021] The igniter main body 31 includes a pair of conductive pins 311, a cylindrical cup body (igniter cup) 312 having one open end and a bottom, a sealing member 313 that closes the opening of the cup body 312, and an ignition charge 314 accommodated in an ignition chamber 315, which is a space formed by the cup body 312 and the sealing member 313. The pair of conductive pins 311 are connected via a bridge wire (not shown) within the ignition chamber 315. When the conductive pins 311 are supplied with current from the outside, the bridge wire, which is a resistor, generates heat and burns the ignition charge 314. Note that the ignition charge 314 is used in existing gas generators. The cup body 312 is a metal member on which, for example, a resin insulating layer is layered. The sealing member 313 is also made of, for example, metal and is insulated from one of the conductive pins 311. The cup body 312 has a radial notch on the surface facing the housing 2 (referred to as the "top surface" for convenience). 3 is a schematic diagram of the top surface of the cup body 312 as viewed from the housing 2 side in the axial direction of the housing 2. Two notches 316 are formed in the shape of a cross on the top surface of the cup body 312, intersecting approximately at the center of the top surface. The notches 316 guide the position at which the cup body 312 breaks when the igniter main body 31 is activated. When the igniter main body 31 is activated, a deployment portion 317, the periphery of which is partially defined by the notches 316 (in other words, the "prospective deployment portion" before activation), deploys toward the gas generating agent 6 accommodated in the housing 2. Note that three or more notches 316 may be formed to intersect at one point, or one prospective deployment portion provided on the top surface of the cup body 312 may be configured to open in a one-sided manner. When the ignition charge 314 in the ignition chamber 315 burns, the cup body 312 splits, for example, starting from the intersection of the notches 316, and combustion products such as flames and combustion gases are released into the housing 2.

[0022] Housing 2 is, for example, a cylindrical member with approximately uniform inner and outer diameters, and forms an outer shell container of gas generator 1. Housing 2 is made of, for example, a metal. Inside housing 2, a combustion chamber 21 is formed between igniter assembly 3 and diffuser portion 4. Combustion chamber 21 contains elastic member 5, such as a coil spring, one end of which is disposed adjacent to igniter assembly 3, and gas generating agent 6 housed on the other end side of elastic member 5. Elastic member 5 has a cylindrical outer shape, and is disposed such that the axial direction of elastic member 5 is the same as the axial direction of housing 2.

[0023] Elastic member 5 is, for example, a compression coil spring. One end 51 of elastic member 5 is formed by shaping a wire into a circle (not shown) and fits into the side periphery of igniter assembly 3. In the examples of FIGS. 1 and 2, one end 51 of elastic member 5 fits into the side periphery of collar portion 32, but one end 51 may also be disposed on the side of retaining portion 33 or cup body 312 of igniter main body 31. Furthermore, elastic member 5 may not fit into the side periphery of igniter assembly 3, but may be fixed by welding or the like.

[0024] The other end 52 of the elastic member 5 may have a spiral (volute) shape when viewed in the axial direction of the elastic member 5. Furthermore, the spiral-shaped other end 52 may have wire intervals that are large enough to prevent the gas generating agent 6 from passing through. For example, the intervals between adjacent wires in the radial direction may be set to approximately 1 mm to 2 mm, which is smaller than the diameter or length of the gas generating agent. This allows the elastic member 5 to urge the gas generating agent 6 toward the diffuser section 4. Furthermore, since the movement of the gas generating agent 6 inside the gas generator 1 is restricted, the gas generating agent 6 can be prevented from being shaken, generating abnormal noise, or being broken. The other end 52 may have a porous member such as punched metal, a plain woven wire mesh, a tatami-woven wire mesh, or the like, disposed at the end of a coil spring or the like. Even in such an embodiment, the gas generating agent 6 can be retained within the housing 2 by making the penetration portion large enough to prevent the gas generating agent 6 from passing through. In this case, the diameter and one side of the opening are set to about 1 mm to 2 mm, for example.

[0025] The elastic member 5 has a reduced diameter portion 53, which has the smallest diameter, inside in the axial direction. The elastic member 5 has a reduced diameter region 54, whose diameter gradually decreases from one end 51 to the reduced diameter portion 53, and an expanded diameter region 55, whose diameter gradually increases from the reduced diameter portion 53 to the other end 52.

[0026] The gas generating agent 6 burns to generate combustion gas. The gas generating agent 6 has a known composition, such as guanidine nitrate (41% by weight), basic copper nitrate (49% by weight), binders, and additives. The individual shape of the gas generating agent 6 may be, for example, a pellet, a disk, a column, or the like. Condition, A single-hole cylindrical material having a through-hole can be used, but the gas generating agent 6 is not limited to the above.

[0027] The diffuser portion 4 is formed integrally with the housing 2 and is a cylindrical portion that closes the other end of the housing 2. As shown in FIG. 1 , for example, the diffuser portion 4 is cylindrical and has a bottom, and includes a side circumferential surface 41 and a closed end 42 opposite the combustion chamber 21. A partition wall 7 is disposed between the combustion chamber 21 and the diffuser portion 4. The partition wall 7 is fixed between two plastically processed portions 43 formed by, for example, crimping the housing 2 to reduce its diameter. The side circumferential surface 41 has gas discharge holes 44. The gas discharge holes 44 are through-holes, and a plurality of the gas discharge holes 44 are provided along the circumferential direction of the side circumferential surface 41. Note that a plurality of the gas discharge holes 44 may be provided in the axial direction of the diffuser portion 4. The gas discharge holes 44 are closed by a blocking member (not shown) such as a sealing tape. The blocking member ruptures when the internal pressure of the gas generator 1 increases due to combustion gas.

[0028] A cylindrical filter 45 is housed inside the side peripheral surface 41, and the combustion gas discharged from the gas discharge holes 44 passes through the filter 45. The filter 45 has, for example, an end on the combustion chamber 21 side abutting against the plastically processed portion 43 and is held between the plastically processed portion 43 and the closed end 42. The filter 45 may be, for example, a flat-woven metal wire placed in a mold and compression-molded into a cylindrical shape with axial through-holes. The filter 45 may also be a columnar shape formed by winding metal wire in multiple layers around a rod-shaped core material and crisscrossing the wires. The filter 45 may also be a columnar shape formed by winding a sheet-like perforated plate, such as expanded metal, punched metal, metal lath, plain-woven wire mesh, or tatami-woven wire mesh, into a cylindrical shape with axial through-holes. When the combustion gas generated by the combustion of the gas generating agent 6 passes through the filter 45, the filter 45 functions as a cooling section that cools the combustion gas, and also filters the combustion gas by collecting combustion residues of the combustion gas.

[0029] The partition wall 7 is, for example, a disk-shaped member, and closes the space between the diffuser section 4 and the combustion chamber 21. In other words, the partition wall 7 is disposed inside the housing 2, and defines the boundary between the combustion chamber 21, which accommodates the gas generating agent 6, and the diffuser section 4. The partition wall 7 may be one that breaks open when the internal pressure of the combustion chamber increases due to combustion gas, or may have through holes that allow the combustion gas to pass through.

[0030] <Operation> When the gas generator 1 is mounted in, for example, an airbag of an automobile, a connector (not shown) is connected to a pair of conductive pins 311, enabling power to be supplied to the igniter assembly 3. In this state, when a sensor (not shown) mounted on the automobile or the like detects an impact, the igniter assembly 3 is activated by an ignition current supplied to the conductive pin 311. The igniter assembly 3 combusts the ignition charge 314 in the cup body 312 and releases the combustion products to the outside of the cup body 312. The gas generating agent 6 in the combustion chamber 21 is ignited by the flame and combustion gas that are combustion products of the ignition charge 314. The gas generating agent 6 generates combustion gas and the like as combustion products when burned. When the internal pressure of the combustion chamber 21 increases, the partition wall 7 ruptures, and the combustion gas passes through the filter 45 of the diffuser portion 4 and is discharged from the gas discharge hole 44. The discharged combustion gas then inflates, for example, an airbag (not shown).

[0031] FIG. 4 is a cross-sectional view of the igniter assembly and its surroundings, showing an example of a state in which the igniter main body is activated. In FIG. 4, the upper surface of the cup body 312 is broken along the notch 316, and the deployment portion 317 opens toward the gas generating agent 6. At this time, the vicinity of the tip of the deployment portion 317 abuts against the reduced diameter portion 53 of the elastic member 5, limiting the angle at which the deployment portion 317 expands. In other words, the reduced diameter portion 53 is provided at a position that contacts the vicinity of the intersection of the notch 316 of the portion to be deployed (deployment portion 317) before activation of the igniter main body 31 (i.e., the most distal end portion of the deployment portion 317 toward the gas generating agent 6 when deployed) during activation of the igniter main body 31, and functions as a restricting portion that restricts deployment of the deployment portion 317 during activation of the igniter main body 31. Note that the deployment of the deployment portion 317 can be restricted by contacting a part of the deployment portion 317 with the reduced diameter portion 53, not limited to the vicinity of the tip of the deployment portion 317. In this case, the part of the unfolded portion 317 that is partway up to the tip contacts the reduced diameter portion 53 , and the tip portion contacts the enlarged diameter region 55 so as to reach therefrom.

[0032] <Effects> The direction in which the igniter body 31 releases combustion products is limited by the angle of the expansion portion 317, as shown by the dashed arrow in FIG. 4 . That is, the reduced diameter portion 53 prevents the combustion products of the igniter body 31 from diffusing toward the inner wall of the housing 2, increasing the amount guided toward the gas generating agent 6 held within the housing 2. Generally, when the combustion products of the gas generating agent 6 are released dispersed over a wide angle, some of the combustion products come into contact with the housing 2 and are cooled. On the other hand, according to this embodiment, the dispersion of the combustion products of the igniter body 31 is suppressed and more of the combustion products are guided toward the gas generating agent 6, improving the ignition performance of the gas generating agent 6. In particular, the igniter body 31 and the combustion chamber 21 are in communication before activation, and there is nothing to obstruct the expansion of the expansion portion 317. Furthermore, the combustion products from the igniter body 31 can ignite the gas generating agent 6 evenly and efficiently. The reduced diameter region 54 also allows the direction of movement of the combustion products from the igniter to converge before being supplied to the gas generating agent 6, increasing the flow rate of the combustion products and improving the ignition ability of the gas generating agent 6. By pre-adjusting the inclination angle of the expanded diameter region 55, the combustion products can be released so as to diffuse over the entire end of the gas generating agent 6 on the igniter assembly 3 side. When a coil spring is used as the elastic member 5, if multiple coil springs are connected in the axial direction, the contact or abutment points of the respective ends may be misaligned, causing the coil springs to tilt, which may make it difficult for the combustion products to be transmitted to the combustion chamber 21. By using a single coil spring, the combustion products can be circulated as designed.

[0033] Fig. 5 is a diagram for explaining the length from the igniter main body to the reduced diameter portion. As shown by the arrow in Fig. 5, if the diameter of the upper surface of cup body 312 is D, length L from the upper surface of cup body 312 to reduced diameter portion 53 can be set to approximately the size shown in the following formula (1). Note that length L is the length from the upper surface of cup body 312 to reduced diameter portion 53 in a state in which elastic member 5 is compressed in its axial direction before activation of gas generator 1. D / 2≦L≦D (1) When the upper surface of the cup body 312 breaks along notches 316 radially extending from the center thereof, the tip of the unfolding portion 317 unfolds in an arc approximately equal to the radius (D / 2) of the cup body 312, with the periphery of the cup body 312 as the rotation axis, toward the diffuser section 4. Therefore, it is preferable to provide the reduced diameter portion 53 at a position approximately D / 2 from the cup body 312. Furthermore, when the entire upper surface of the cup body 312 unfolds in a one-sided opening manner, the tip of the unfolding portion 317 unfolds in an arc approximately equal to the diameter (D) of the cup body 312, with the part of the periphery of the cup body 312 as the rotation axis, toward the diffuser section 4. Therefore, it is preferable to provide the reduced diameter portion 53 at a position approximately D from the cup body 312. Therefore, it is preferable that the length L from the top surface of the cup body 312 to the reduced diameter portion is set to be approximately equal to or greater than the radius of the cup body 312 and equal to or less than the diameter of the cup body 312 .

[0034] The elastic member 5 may be formed so that the expanded diameter region 55 has a lower elastic modulus than the reduced diameter region 54. The elastic modulus can be made different, for example, by varying the thickness or number of turns of the coil spring. In this way, when the gas generator 1 is filled with gas generating agent 6, even if there is some variation in the amount of gas generating agent 6, the expanded diameter region 55 deforms preferentially, and the length of the reduced diameter region 54 becomes approximately constant. In other words, the length from the igniter body 31 to the reduced diameter portion 53 becomes approximately constant, and the tip of the cleaved cup body 312 and the reduced diameter portion 53 of the elastic member 5 come into contact in a pre-designed positional relationship.

[0035] <Modification> FIG. 6 is a schematic cross-sectional view of the igniter assembly and its surroundings according to a first modified example. In this modified example, components corresponding to those in the above-described embodiment are designated by the same reference numerals, and differences will be mainly described. Thin dashed lines indicate the outline of the cross-sectional shape of the elastic member 5. Thick dashed lines indicate the cross-sectional shape of the deployment portion 317 when ruptured. In the example shown in FIG. 6, the elastic member 5 is disposed to the side of the retaining portion 33. Note that the elastic member 5 may be fitted into the retaining portion 33. The elastic member 5 also has a constant diameter region 56 with a constant diameter on the igniter assembly 3 side. The elastic member 5 also has a reduced diameter portion 53 at a position that contacts the intended deployment portion (deployment portion 317) when the igniter body 31 is activated, a reduced diameter region 54 whose diameter gradually decreases from near the top surface of the cup body 312 toward the reduced diameter portion 53, and an expanded diameter region 55 whose diameter gradually increases from the reduced diameter portion 53 toward the diffuser portion 4.

[0036] FIG. 7 is a schematic cross-sectional view of the igniter assembly and its surroundings according to a second modified example. In the example of FIG. 7, a portion of the side surface of collar portion 32 includes a portion formed flush with the side surface of retaining portion 33. Elastic members 5 are disposed on the sides of collar portion 32 and retaining portion 33. Note that elastic member 5 may be fitted to collar portion 32 and retaining portion 33. In this modified example, elastic member 5 also has constant diameter region 56 with a constant diameter on the igniter assembly 3 side. Elastic member 5 has reduced diameter portion 53 at a position that contacts the intended deployment portion (deployment portion 317) when igniter main body 31 is activated, as well as reduced diameter region 54 whose diameter gradually decreases from near the upper surface of cup body 312 toward reduced diameter portion 53, and expanded diameter region 55 whose diameter gradually increases from reduced diameter portion 53 toward diffuser portion 4.

[0037] FIG. 8 is a schematic cross-sectional view of the igniter assembly and its surroundings according to a third modified example. In the example of FIG. 8, an elastic member 5 is disposed on the side of the cup body 312. The elastic member 5 may be fitted to the cup body 312. However, to prevent damage to an insulating layer, such as an insulating sheet, formed on the surface of the cup body 312, it is preferable to provide a gap between the elastic member 5 and the cup body 312. The elastic member 5 has a constant diameter region 56 with a constant diameter on the igniter assembly 3 side. The elastic member 5 does not have a reduced diameter region 54. That is, the elastic member 5 has an expanded diameter region 55 at the end of the constant diameter region 56 on the diffuser section 4 side, the diameter of which gradually increases toward the gas generating agent 6 side. When the igniter main body 31 is activated, the vicinity of the tip of the intended deployment portion (deployment portion 317) is in contact with the expanded diameter region 55.

[0038] FIG. 9 is a schematic cross-sectional view of the periphery of an igniter assembly according to a fourth modified example. In the example of FIG. 9, elastic member 5 is disposed on the side of retaining portion 33. Note that elastic member 5 may be fitted into retaining portion 33. Elastic member 5 has constant diameter region 56, with a constant diameter, on the igniter assembly 3 side. Elastic member 5 has reduced diameter portion 53 at a position that contacts the intended deployment portion (deployment portion 317) when igniter main body 31 is activated, and also has reduced diameter region 54, the diameter of which gradually decreases from the vicinity of the upper surface of cup body 312. In this modified example, expanded diameter region 55 is also a coil spring, but a porous member 8 is disposed on its tip surface (other end portion 52). Porous member 8 may be a non-elastic member, for example, formed of punched metal or wire mesh.

[0039] FIG. 10 is a schematic cross-sectional view of the igniter assembly and its surroundings according to a fifth modified example. In the example of FIG. 10, an elastic member 5 is arranged on the side of the igniter body 31. The elastic member 5 includes, for example, three or more leaf springs 57 arranged in the circumferential direction and an annular member 58 connected to the leaf springs 57 and disposed along the inner periphery of the housing 2, which are integrally formed. A porous member 9 such as a wire mesh is connected to the annular member 58 on the diffuser section 4 side. The porous member 9 is circular in a cross-sectional view (not shown) of the housing 2, and has a mesh size that does not allow the gas generating agent 6 to pass through. In this modified example, the intended deployment portion (deployment portion 317) may be configured to come into contact with the annular member 58 when the igniter body 31 is activated.

[0040] <Other> Each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. In addition, the restricting portion does not have to be the portion with the smallest diameter in the elastic member 5, as long as it is a portion that abuts against the cleaved cup body 312. In addition, as long as the elastic member 5 includes a restricting portion that restricts the deployment direction of the cleaved cup body 312, the diameter of the restricting portion may be constant along the entire axial length.

[0041] The igniter main body 31 may be provided with a metallic charge holder on the sealing member 313 (on the combustion chamber 21 side) that surrounds the ignition charge from the side (radially outside the housing 2), as shown in FIG. 3 of JP 2002-79903 A, for example.

[0042] As shown in the embodiment and modified example, it is preferable that one elastic member 5 is arranged between the igniter assembly 3 and the combustion chamber 21. Furthermore, when the other end 52 of the elastic member 5 is spirally shaped, a through-hole (i.e., a gap) is formed between adjacent wires in the radial direction. In this case, it is preferable that the space formed inside the elastic member 5 and in which the igniter body 31 is arranged communicates with the space in the combustion chamber 21 in which the gas generating agent 6 is arranged via the through-hole even before activation of the gas generator 1. In other words, since the igniter body 31 and the gas generating agent 6 are in communication with each other even before activation of the gas generator 1, combustion products from the ignition charge 314 can easily reach the gas generating agent 6. This improves the ignition performance and combustion performance of the gas generating agent 6.

[0043] The spiral-shaped other end 52 may have a shape in which the radial center thereof protrudes toward the combustion chamber 21 or the igniter body 31. The cross-sectional shape from the protruding center toward the periphery of the other end 52 may be an annular inclined surface or a curved inclined surface. This allows the ignition surface of the gas generating agent 6 facing the igniter body 31 to be widened, thereby improving ignition performance. A known enhancer may be disposed between the igniter body 31 and the gas generating agent 6. This also improves the ignition and combustion performance of the gas generating agent 6. For example, the radial center of the other end 52 of the elastic member 5 may protrude toward the igniter body 31, and an enhancer may be disposed in a recess recessed toward the combustion chamber 21. The portion protruding toward the combustion chamber 21 or the igniter body 31 is not limited to the radial center, and multiple portions may protrude. Furthermore, the partially protruding other end 52 does not need to be spiral-shaped, but may be formed from a porous material such as expanded metal, punched metal, metal lath, plain woven wire mesh, or tatami woven wire mesh, and may be used in combination with a coil spring.

[0044] Furthermore, in the elastic member 5, which is a coil spring, the distance between adjacent wire rods in the axial direction in the expanded diameter region 55 may be shorter than the distance between adjacent wire rods in the axial direction in the reduced diameter region 54. In other words, the spacing between the wire rods in the expanded diameter region 55 can be made closer than in the reduced diameter region 54, which faces the cup body 312 (deployment portion 317) that is cleaved when the igniter body 31 is activated, thereby making it possible to suppress the discharge of combustion products around the elastic member 5. [Explanation of symbols]

[0045] 1: Gas generator 2: Housing 21: Combustion chamber 3:Igniter assembly 31:Igniter body 311: Conductive pin 312: Cup body 313: Sealing member 314: Ignition powder 315:Ignition chamber 316: Notch 317: Development section 32: Color section 33: Holding part 4: Diffuser section 41: Side surface 42: Closed end 43: Plastic processing section 44: Gas exhaust hole 45: Filter 5: Elastic member 51:One end 52:Other end 53: Reduced diameter part 54: Diameter reduction area 55: Expansion area 56: Equal diameter area 57: Leaf spring 58: Circular member 6: Gas generator 7: Compartment wall 8: Porous material 9: Porous material

Claims

1. an igniter assembly including an igniter body including an igniter cup that accommodates an ignition charge and is cleaved by combustion products generated by combustion of the ignition charge, and a conductive pin that supplies current to ignite the ignition charge, a collar portion that holds the igniter body, and a holding portion that is interposed between the igniter body and the collar portion and fixes the igniter body to the collar portion, and that releases the combustion products; a cylindrical housing having a combustion chamber that accommodates a gas generating agent that is ignited by the combustion products, the housing having a gas discharge hole that discharges combustion gas generated by combustion of the gas generating agent; a cylindrical elastic member disposed within the housing between the igniter assembly and the gas generating agent, the elastic member having an axial direction that is the same as the axial direction of the housing, the elastic member having a restricting portion on an inner periphery thereof that restricts a direction in which the igniter cup, which has been split open, expands; A gas generator comprising:

2. the igniter cup has a peripheral edge that is partly defined by a notch formed on a cleavage surface facing the combustion chamber and that guides a rupture position, and has a planned deployment portion that deploys while the other part of the peripheral edge is connected to the igniter cup when the ignition charge is burned, The restricting portion is provided at a position where it comes into contact with the expanded portion to be expanded.

2. The gas generator according to claim 1.

3. The restricting portion is a reduced diameter portion where the inner diameter of the elastic member is smallest.

3. A gas generator according to claim 1 or 2.

4. The elastic member is configured to reduce in diameter from the igniter assembly side toward the reduced diameter portion.

4. The gas generator according to claim 3.

5. The elastic member expands in diameter from the reduced diameter portion toward the gas generating agent.

4. The gas generator according to claim 3.

6. The elastic member has a side of the igniter assembly that fits into the collar portion or the holding portion.

3. A gas generator according to claim 1 or 2.

7. The elastic member is configured to be closer to the gas generating side than to the igniter assembly side with the restriction portion as a reference. The side with the active ingredient has a lower elastic modulus 3. A gas generator according to claim 1 or 2.

8. The elastic member is a coil spring.

3. A gas generator according to claim 1 or 2.

9. The elastic member has a through-hole at an end on the gas generating agent side, the through-hole being large enough to allow the combustion products to pass through but not the gas generating agent, and urges the gas generating agent in the opposite direction to the igniter assembly.

3. A gas generator according to claim 1 or 2.

10. A gas generator as described in claim 1 or 2, wherein one elastic member is arranged between the igniter assembly and the combustion chamber.

11. The other end of the elastic member is spiral-shaped, and a through-hole is formed between adjacent wire rods in the radial direction, 9. The gas generator according to claim 8, wherein a space formed inside the elastic member and in which the igniter body is disposed and a space in the combustion chamber in which the gas generating agent is disposed are communicated via the through-hole in a state before activation of the gas generator.

12. A gas generator as described in Claim 11, wherein the other end has a shape in which the radial center protrudes toward the combustion chamber or the igniter body.

13. A gas generator as described in claim 12, in which a known transfer charge is arranged between the igniter body and the gas generating agent.

14. The elastic member has a reduced diameter portion at a position where it comes into contact with the intended expansion portion when the igniter body is activated, and also has a reduced diameter region where the diameter gradually decreases from near the top surface of the igniter cup toward the reduced diameter portion, and an expanded diameter region where the diameter gradually increases from the reduced diameter portion toward the combustion chamber side. The gas generator according to claim 8 which relies on claim 2, wherein a distance between adjacent wire rods in the axial direction in the diameter expanding region is shorter than a distance between adjacent wire rods in the axial direction in the diameter reducing region.

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