JP7748396B2 - Gas generator - Google Patents

Description

The present invention relates to a gas generator incorporated into an airbag device as an occupant protection device installed in an automobile, etc., and more specifically to a so-called cylinder-type gas generator having a long cylindrical shape.

The long cylindrical housing of a cylinder-type gas generator is generally configured so that one end is closed by a blocking member and the other end is closed by a holder having an ignition section (see, for example, Patent Document 1 below).

Patent No. 5455932

However, with regard to gas generators such as those described in the above patent documents, there is a demand for further weight reduction and cost reduction through simplified components.

Therefore, the present invention aims to provide a gas generator that is lighter than conventional models and has simplified parts, thereby reducing costs.

(1) A gas generator of the present invention comprises a long cylindrical housing loaded with a gas generating agent that generates gas by combustion, containing a filter inside through which the gas passes, and having a gas outlet formed at a position corresponding to the filter for ejecting the gas; an igniter capable of igniting and burning the gas generating agent; a holder that holds a part of the igniter and is fixed to one axial end of the housing; and a closure member that is fixed to the other axial end of the housing, wherein the closure member is fixed to the housing by deforming the side of a bottomed tubular member that is inserted partway into the housing from the other end of the housing and reducing the diameter of the side of the bottomed tubular member together with the housing from the outside at at least one location, and the closure member defines an internal space of the bottomed tubular member after deformation that is a space shaped to match the shape of the bottomed tubular member after deformation and that is a hollow space for reducing internal pressure during gas generation . Here, "reducing the diameter at one location" means, for example, reducing the diameter in an annular manner around the entire circumference of the side surface of the housing at one location on the side surface of the housing.

( 2 ) In the gas generator of (1) above, it is preferable that the bottomed tubular member is fixed to the housing by reducing the diameter of the side surface of the end of the bottomed tubular member together with the housing from the outside.

( 3 ) In the gas generator of (1) or (2 ) above, the bottomed tubular member has a first tubular portion disposed on the end side of the housing, a second tubular portion having a diameter larger than that of the first tubular portion, and a connecting portion connecting the first tubular portion and the second tubular portion, and it is preferable that at least one location where the diameter reduction process is performed is located on the first tubular portion side of the connecting portion.

( 4 ) In the gas generators of (1) to ( 3 ) above, it is preferable that the diameter-reducing process is performed at two or more locations.

( 5 ) The present invention comprises a long cylindrical housing loaded with a gas generating agent that generates gas by combustion, containing a filter inside through which the gas passes, and having a gas outlet formed at a position corresponding to the filter for ejecting the gas; an igniter capable of igniting and burning the gas generating agent; a holder that holds a part of the igniter and is fixed to one axial end of the housing; and a blocking member that is fixed to the other axial end of the housing, wherein the blocking member is fixed to the housing by deforming the side of a bottomed tubular member that is inserted partway into the housing from the other end of the housing together with the housing at at least one location from the outside, and the diameter reduction processing is performed at two or more locations. When the diameter reduction processing is performed at two or more locations, a gap may be formed between the inner wall of the housing and the outer wall of the blocking member between adjacent positions of the diameter reduction processing.

( 6 ) In the gas generator of ( 5 ) above, it is preferable that the gap is formed by reducing the diameter of adjacent positions to be reduced in the same process.

The present invention makes it possible to provide a gas generator that is lighter than conventional models and has simplified parts, resulting in cost savings.

1 is a schematic diagram (partially omitted) showing the internal structure of a gas generator according to a first embodiment of the present invention, shown partially in cross section. FIG. FIG. 5 is a schematic diagram (partially omitted) showing the internal structure of a gas generator according to a second embodiment of the present invention, shown partially in cross section. FIG. 10 is a schematic diagram (partially omitted) showing the internal structure of a gas generator according to a third embodiment of the present invention, shown partially in cross section. FIG. 10 is a schematic diagram (partially omitted) showing the internal structure of a gas generator according to a fourth embodiment of the present invention, shown partially in cross section. FIG. 11 is a schematic diagram (partially omitted) showing the internal structure of a gas generator according to a fifth embodiment of the present invention, shown partially in cross section. 6A is a cross-sectional view (partially omitted) for explaining the diameter reduction process of the gas generator of FIG. 5, and FIGS. 6B and 6C are cross-sectional views (partially omitted) showing modified examples of FIG. 6A. 6 is an enlarged cross-sectional view of the end of the gas generator of FIG. 5. FIG.

First Embodiment
Hereinafter, with reference to FIG. 1, the internal structure of a cylinder-type gas generator according to an embodiment of the present invention will be described.

(Configuration of gas generator 100)
The gas generator 100 has a long, approximately cylindrical outer shape and includes a housing 10, a holder 20 attached to one open end of the housing 10, and a blocking member 12 attached to the other end of the housing 10 so as to block the other open end of the housing 10.

The housing 10 is a long, cylindrical member having peripheral walls 10a and 10e and openings at both axial ends. The closure member 12 has an annular groove 13 formed by reducing the diameter of the peripheral surface of a bottomed, cylindrical member having a predetermined thickness through crimping (an example of a diameter-reducing process) as described below, and is formed into a generally pot-shaped configuration with an internal space 12a. The annular groove 13 formed by crimping extends circumferentially on the peripheral surface of the closure member 12. Gas outlets 11 are provided in the peripheral wall of the housing 10 near the end where the closure member 12 is attached. These gas outlets 11 are holes for ejecting gas generated inside the gas generator 100 to the outside, and multiple gas outlets 11 are provided along the circumferential and axial directions of the housing 10.

The blocking member 12 is made of a metal such as stainless steel, iron steel, aluminum alloy, or stainless alloy. As shown in Figure 1, with a portion of the blocking member 12 inserted into one open end of the housing 10, the peripheral wall 10a of the housing 10 corresponding to part of the peripheral surface of the blocking member 12 is narrowed radially inward (crimped) to form the annular groove 13, thereby crimping and fixing the blocking member 12 to the housing 10.

The holder 20 is made of a metal such as stainless steel, iron steel, aluminum alloy, or stainless alloy, and has a tapered fitting portion 23 into which the igniter 50 fits, an annular groove 22 formed on the outer peripheral surface extending circumferentially for crimping, and a fitting portion 21 on the side opposite the holding position of the igniter 50 into which a female connector (not shown) for supplying electricity to the igniter 50 can fit. The holder 20 is crimped to the housing 10 by reducing (crimping) the peripheral wall 10e of the housing 10 radially inward at a portion corresponding to the annular groove 22 on the outer peripheral surface of the holder 20 to engage with the annular groove 22.

As mentioned above, a female connector is formed in the mating portion 21 of the holder 20. This female connector is the portion to which a male connector of a harness that transmits signals from a collision detection means provided separately from the gas generator 100 is connected. A retainer (not shown) is attached to the female connector. This retainer is attached to prevent malfunction of the cylindrical gas generator 100 due to electrostatic discharge, etc., during transportation of the gas generator 100, and when the male connector of the harness is inserted into the female connector, contact with the terminal pin 52 is released.

As shown in Figure 1, an igniter 50 is disposed at one axial end of the housing 10 (i.e., the portion closer to the holder 20) as a means for igniting the gas generating agent 31. The igniter 50 and the holder 20 that secures the igniter 50 function as ignition means that generate a flame for burning the granular gas generating agent 31, which will be described later.

As shown in FIG. 1, the igniter 50 is inserted into the fitting 23 of the holder 20 and held together with a generally cylindrical member 53 (described below). More specifically, the igniter 50 comprises a base frame through which a pair of terminal pins 52 are inserted and held, and a squib cup 51 (cup-shaped member) attached to the base frame. A resistor (bridge wire) is attached to connect the tips of the terminal pins 52 inserted into the squib cup 51, and an ignition charge is filled in the squib cup 51 so as to surround or contact the resistor. Nichrome wire or the like is typically used as the resistor, and ZPP (zirconium potassium perchlorate), ZWPP (zirconium tungsten potassium perchlorate), lead tricinate, or the like is typically used as the ignition charge. In addition to the ignition charge, a transfer charge may also be filled into the squib cup 51. Examples of transfer charges that can be placed together with the ignition charge include a composition consisting of a metal/oxidizer, such as boron/potassium nitrate, a composition consisting of titanium hydride/potassium perchlorate, or a composition consisting of boron/5-aminotetrazole/potassium nitrate/molybdenum trioxide.

When a collision is detected, a predetermined amount of current flows through the resistor via the terminal pin 52. This current flow through the resistor generates Joule heat, which causes the ignition charge to begin burning. The high-temperature flame generated by the combustion ruptures the squib cup 51 containing the ignition charge. If nichrome wire is used for the resistor, the time from when current flows through the resistor to when the igniter 50 is activated is less than 2 milliseconds.

The squib cup 51 is generally made of metal or resin. A generally cylindrical member 53, which covers the peripheral wall of the squib cup 51 except for the portion near the tip, is fixed to the holder 20 by crimping together with the igniter 50 via the crimping portion 24. The generally cylindrical member 53 is a directional member that directs the flame generated in the igniter 50 toward the container 34 upon activation. A coil spring 54 is provided around the squib cup 51 and the generally cylindrical member 53, along the inner wall of the housing 10. One end of this coil spring 54 abuts against the end of the lid portion 34b of the container 34 (described below), and the other end abuts against the end on the inner side of the holder 20.

As shown in Figure 1, a cylindrical container 34 containing a gas generating agent 31 and other materials is sealed in the interior space of the housing 10, and a filter 41 are loaded side by side in the axial direction of the housing 10. The container 34 is preferably made of a metal such as aluminum.

The container 34 has a bottomed cylindrical portion 34a and a lid portion 34b, and contains a gas generating agent 31, a coil spring 35, an AI agent 32, and a cover member 33. The lid portion 34b and the tip of the igniter 50 are spaced a predetermined distance apart. This makes it easier for the squib cup 51 to split open when the igniter 50 is activated.

The gas generant 31 is a molded, integrally formed product that is ignited by a flame generated by ignition by the igniter 50 and burns to generate gas. The gas generant 31 is generally formed as a molded product containing fuel, an oxidizer, and an additive. Examples of fuels that can be used include triazole derivatives, tetrazole derivatives, guanidine derivatives, azodicarbonamide derivatives, hydrazine derivatives, and combinations thereof. Specifically, nitroguanidine, guanidine nitrate, cyanoguanidine, and 5-aminotetrazole are preferred. Examples of oxidizers that can be used include basic metal nitrates such as basic copper nitrate, basic metal carbonates such as basic copper carbonate, perchlorates such as ammonium perchlorate and potassium perchlorate, and nitrates containing cations selected from alkali metals, alkaline earth metals, transition metals, and ammonia. Examples of nitrates that can be used include sodium nitrate and potassium nitrate. Examples of additives include binders, slag-forming agents, and combustion modifiers. Suitable binders include organic binders such as cellulose derivatives (e.g., hydroxypropylene methyl cellulose), metal salts of carboxymethyl cellulose, and stearates, as well as inorganic binders (e.g., synthetic hydroxytalcite and acid clay). Suitable slag-forming agents include silicon nitride, silica, and acid clay. Suitable combustion-adjusting agents include metal oxides, ferrosilicon, activated carbon, and graphite.

As shown in FIG. 1, the coil spring 35 is spirally wound so that its overall appearance resembles a truncated cone. One end of the coil spring 35 abuts the lid portion 34b, while the other spirally formed end abuts the gas generating agent 31, exerting an elastic force on the gas generating agent 31. This bias secures the gas generating agent 31 in the container 34, sandwiched between the coil spring 35, the end of the filter 41 facing the coil spring 35, and the bottom of the bottomed tubular portion 34a. The coil spring 35's overall truncated cone shape from the igniter 50 side to the gas generating agent 31 side makes it easier to direct the flame emitted from the igniter 50 toward the gas generating agent 31.

The AI agent 32 has an auto-ignition (AI) function that allows it to ignite automatically without the activation of the igniter 50. More specifically, the AI agent 32 ignites automatically at a lower temperature than the gas generating agent 31. Therefore, in the unlikely event of a fire or other incident occurring in a vehicle equipped with an airbag system or the like incorporating the gas generator 100, it is possible to prevent the gas generator 100 from malfunctioning due to external heating. A cover member 33 that holds the AI agent 32 is hermetically housed in the bottom of the container 34 on the closing member 12 side. The cover member 33 has multiple holes.

The filter 41 is a cylindrical member with a generally cylindrical hollow portion 41a in the center. Using a filter 41 made of the cylindrical member reduces the flow resistance of the working gas during operation, enabling efficient gas flow. The filter 41 may be made of wire material made of metal such as stainless steel or steel, or a wound or pressed mesh material. Specifically, a knitted wire mesh, a plain weave wire mesh, or an assembly of crimped metal wire material may be used. The filter 41 functions as a cooling means for cooling the gas generated in the container 34 by removing the high-temperature heat of the gas as it passes through the filter 41, and also as a removal means for removing slag and other contaminants contained in the gas. Here, as a variation of the filter 41, a filter with a labyrinth-shaped flow path formed by combining generally cylindrical or cone-shaped metal components may be used. This allows the working gas to be redirected in various directions, thereby cooling the gas and removing slag.

While the above-described embodiments of the present invention have been described using a filter made of knitted wire mesh, it is also possible to use a filter made by winding punched metal or expanded metal instead. Here, punched metal refers to a metal plate with only openings (i.e., no protrusions around the edges of the openings), and expanded metal refers to a metal plate made by cutting slits in a staggered pattern, for example, and then expanding the slits to create a mesh-like structure. Even when such punched metal or expanded metal is used in place of the knitted wire mesh, the same effects as those described in the above-described embodiments of the present invention can be achieved.

In addition, in the punched metal and expanded metal described above, the filter is constructed as a laminate by winding a single metal plate-like member, but the filter configuration is not limited to this. That is, each layer may be constructed from a different metal plate-like member and these may be combined to form a laminate filter, or some of the multiple layers may be formed by winding a single metal plate-like member, and the remaining layers may be formed by winding another single metal plate-like member, and these may be combined to form a laminate filter.

A bottomed, cylindrical bypass prevention member 36 is provided between the filter 41 and the container 34 to axially separate the housing 10. This bypass prevention member 36 has a through-hole 36a at approximately the center of its bottom, through which the generated gas can pass. The bypass prevention member 36 covers the filter 41-side end of the bottomed, cylindrical portion 34a of the container 34 and its periphery, and is disposed so that its outer wall abuts against the inner wall of the housing 10. This prevents the generated gas from bypassing between the inner wall of the housing 10 and the outer periphery of the filter 41 and leaking out of the gas outlet 11. In other words, the bypass prevention member 36 allows gas generated on the container 34 side to flow into the filter 41 side via the through-hole 36a.

Next, the operation of the gas generator 100 described above during activation will be described. When a vehicle equipped with an airbag device incorporating the gas generator 100 of this embodiment collides, the collision is detected by collision detection means separately provided in the vehicle, and the igniter 50 is activated based on this detection. When the igniter 50 is activated, the pressure inside the igniter 50 increases due to combustion of the ignition charge, causing the tip of the squib cup 51 of the igniter 50 to rupture, and a flame flows from the tip of the squib cup 51 of the igniter 50 toward the container 34 inside the housing 10.

The flames flowing in in this manner split open the lid portion 34b of the container 34, igniting and burning the gas generating agent 31 inside the container 34 and generating a large amount of gas. This combustion of the gas generating agent 31 increases the pressure inside the container 34, and the generated gas splits open the end of the container 34 on the closure member 12 side and flows into the hollow portion 41a and internal space 12a through the through-hole 36a of the bypass prevention member 36. The generated gas then passes through the filter 41 and is ejected from the gas outlet 11 to the outside of the gas generator 100. However, because it passes through the filter 41, the generated gas is cooled to a predetermined temperature. The gas ejected from the gas outlet 11 is then guided into the interior of the airbag, inflating and deploying the airbag.

(Major features of gas generator 100)
According to this embodiment, an object is to provide gas generator 100 which can be made lighter than when a conventional closing member is used, and in which costs are reduced by simplifying the components.

In addition, in this embodiment, since the blocking member 12 and the housing 10 are both crimped, the crimping position is not particularly important as long as it allows the blocking member 12 to be fixed to the housing 10. Therefore, there is no need to manage the crimping position (such as accurate positioning) as much as in the past, which simplifies the manufacturing process.

In addition, in this embodiment, an internal space 12a is provided in the blocking member 12, so the spatial volume can be increased compared to when using conventional blocking members, making it possible to reduce the internal pressure when gas is generated.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to Fig. 2. In this embodiment, parts having the same reference numerals as those in the first embodiment down to the last two digits are the same as those in the first embodiment, and therefore their description may be omitted. Furthermore, parts not particularly described in this embodiment are the same as those in the first embodiment, and therefore their description and illustration may be omitted.

The gas generator 200 of this embodiment differs from the first embodiment in that, instead of the blocking member 12 in the first embodiment, whose bottom protrudes from the end of the housing 10, a blocking member 212 is used whose bottom is formed so as to be in approximately the same position as the end of the housing 210.

The blocking member 212 is formed so that its bottom is approximately in the same position as the end of the housing 210, but the side portion 212b is longer in the axial direction than the blocking member 12 of the first embodiment, and an internal space 212a with sufficient spatial volume is formed.

This embodiment can achieve the same effects as the first embodiment. Furthermore, because the bottom of the blocking member 212 is formed so that it is positioned approximately flush with the end of the housing 210, an internal space 212a with sufficient spatial volume can be secured. This makes it possible to increase the spatial volume compared to using conventional blocking members while maintaining the overall axial length at the same level as or shorter than conventional devices, thereby enabling a reduction in internal pressure during gas generation.

Third Embodiment
Next, a third embodiment of the present invention will be described with reference to Fig. 3. In this embodiment, parts having the same reference numerals as those in the first embodiment down to the last two digits are the same as those in the first embodiment, and therefore their description may be omitted. Furthermore, parts not particularly described in this embodiment are the same as those in the first embodiment, and therefore their description and illustration may be omitted.

The gas generator 300 has a long, approximately cylindrical outer shape and includes a housing 310, a holder 320 attached to one open end of the housing 310, and a blocking member 312 attached to the other end of the housing 310 so as to block the other open end of the housing 310.

The housing 310 has peripheral walls 310a, 310b, 310c, 310d, and 310e and is made of a long, cylindrical member with openings at both axial ends. The closure member 312 has an annular groove 313 formed by crimping the peripheral surface of a bottomed, cylindrical member with a predetermined thickness to reduce its diameter, and is formed into a roughly pot-shaped shape with an internal space 312a. The annular groove 313 formed by crimping extends circumferentially on the peripheral surface of the closure member 312. Furthermore, a gas outlet 311 is provided in the peripheral wall of the housing 310 near the end where the closure member 312 is attached. The gas outlet 311 is a hole for ejecting gas generated inside the gas generator 300 to the outside, and multiple gas outlets 311 are provided along the circumferential and axial directions of the housing 310.

The igniter 350 is held in place by being inserted into the fitting portion 323 of the holder 320.

The peripheral wall 310c of the housing 310, corresponding to the squib cup 351 of the igniter 350, is tapered radially inward (crimped) to form a cylindrical shape that matches the outer periphery of the squib cup 351, thereby crimping and fixing the squib cup 351 to the housing 310. This allows the peripheral wall 310c to function as a directional member that directs the flame emitted from the tip of the igniter 350 toward the gas generant 331. The peripheral wall 310b of the housing 310 is gradually tapered from the middle of the housing 310 toward the peripheral wall 310c. This allows the peripheral wall 310b to position the end of the receptacle 334 (described later) within the housing 310. The peripheral wall 310d of the housing 310 is tapered, expanding in diameter from the peripheral wall 310c to the middle of the housing 310, to match the outer shape of the squib cup 351. As a result, the squib cup 351 is sandwiched between the inner wall of the peripheral wall 310 d and the fitting portion 323 , and the igniter 350 can be fixed to the housing 310 and the holder 320 .

The interior space of the housing 310 is filled with a cylindrical container 334 that contains a gas generating agent 331, a filter 341, and other components. The container 334 is preferably made of a metal such as aluminum.

The container 334 has a bottomed cylindrical portion 334a and a lid portion 334b, and contains a gas generating agent 331, a coil spring 335, a filter 341, an AI agent 332, and a cover member 333. The lid portion 334b and the tip of the igniter 350 are spaced a predetermined distance apart. This makes it easier for the squib cup 351 to split open when the igniter 350 is activated.

The filter 341 is a cylindrical member with a roughly cylindrical hollow portion 341a in the center, and the hollow portion 341a is filled with the gas generating agent 331. The AI agent 332 has an auto-ignition (AI) function that allows it to ignite automatically without the activation of the igniter 350. A cover member 333 that holds the AI agent 332 is hermetically housed between the filter 341 and the bottom of the container 334 on the blocking member 312 side. The cover member 333 has multiple holes.

Next, the operation of the gas generator 300 described above during activation will be described. When a vehicle equipped with an airbag device incorporating the gas generator 300 of this embodiment collides, the collision is detected by collision detection means separately provided in the vehicle, and the igniter 350 is activated based on this detection. When the igniter 350 is activated, the pressure inside the igniter 350 increases due to combustion of the ignition charge, causing the tip of the squib cup 351 of the igniter 350 to rupture, and a flame flows from the tip of the squib cup 351 of the igniter 350 toward the container 334 inside the housing 310.

The flames flowing in in this manner split open the lid portion 334b of the container 334, igniting and burning the gas generating agent 331 inside the container 334 and generating a large amount of gas. This combustion of the gas generating agent 331 increases the pressure inside the container 334, and the generated gas splits open the end of the container 334 on the closing member 312 side and flows into the internal space 312a. The generated gas then passes through the filter 341 and splits open the portion of the container 334 that is in contact with the gas outlet 311. Furthermore, as the portion of the container 334 that is in contact with the gas outlet 311 splits open, the generated gas is ejected from the gas outlet 311 to the outside of the gas generator 300. However, because the gas passes through the filter 341, the generated gas is cooled to a predetermined temperature. The gas ejected from the gas outlet 311 is then guided into the interior of the airbag, inflating and deploying the airbag.

This embodiment can achieve the same effects as the first embodiment.

Fourth Embodiment
Next, a fourth embodiment of the present invention will be described with reference to Fig. 4. In this embodiment, parts having the same reference numerals as those in the first or third embodiment down to the last two digits are the same as those in the first or third embodiment, and therefore their description may be omitted. Furthermore, parts not particularly described in this embodiment are the same as those in the first or third embodiment, and therefore their description and illustration may be omitted.

The gas generator 400 of this embodiment differs from the third embodiment in that, instead of the blocking member 412 in the third embodiment whose bottom protrudes from the end of the housing 310, a blocking member 412 whose bottom protrudes only slightly from the end of the housing 410 is used.

The bottom of the blocking member 412 protrudes slightly from the end of the housing 410, but the side portion 412b is longer in the axial direction than the blocking member 312 of the third embodiment, forming an internal space 412a with sufficient spatial volume.

This embodiment can achieve the same effects as the first embodiment. Furthermore, because the bottom of the blocking member 412 protrudes slightly from the end of the housing 410, the internal space 412a can be secured with sufficient spatial volume while maintaining the overall axial length the same as conventional devices. This makes it possible to increase the spatial volume compared to using conventional blocking members while maintaining the overall axial length the same as conventional devices, thereby reducing internal pressure during gas generation.

Fifth Embodiment
Next, a fifth embodiment of the present invention will be described with reference to Figures 5 to 7. In this embodiment, parts having the same reference numerals as those in the first embodiment down to the last two digits are the same as those in the first embodiment unless otherwise specified, and therefore their description may be omitted. Furthermore, parts in this embodiment that are not particularly described are also the same as those in the first embodiment, and therefore their description and illustration may be omitted.

The gas generator 500 according to this embodiment differs from the first embodiment mainly in that (1) there are two diameter-reducing processes for fixing the blocking member 512 to the end of the housing 510, (2) the coil spring 535 is disposed so that one end abuts the tip side (flame ejection side) of the igniter 550 and is formed in a spiral shape that expands in diameter from one end to the other, with the other end pressing the gas generating agent 531 toward the bypass prevention member 536, and (3) there is no container. Providing multiple diameter-reducing processes (crimping processes) as described above in (1) enhances the prevention of the blocking member 512 from coming loose during gas generation, thereby reducing the amount of deformation of the housing 510 associated with the diameter-reducing processes (crimping processes), and thereby improving the effectiveness of preventing the housing 510 from breaking.

As shown in FIG. 6(a), the closure member 512 is fabricated by placing a bottomed, cylindrical closure member precursor 512A on the end of the housing precursor 510A. Then, a diameter-reducing process (such as crimping) is performed in the direction of the arrows at two locations simultaneously (including the case where two locations are simultaneously processed in the same process) or one location at a time. This process forms peripheral walls 510a and 510b and annular grooves 513 and 514, as shown in FIGS. 5 and 7, thereby securing the closure member 512 to the housing 510. Furthermore, an annular gap 515 is preferably formed between the inner wall of the housing 510 and the outer wall of the closure member 512, between the annular grooves 513 and 514. The formation of the gap 515 disperses stress caused by the crimping process and prevents fracture of the housing 510 due to the peripheral walls 510a and 510b or the annular grooves 513 and 514. In other words, for example, by forming gap 515, it is possible to realize a design that can prevent housing 510 from breaking during operation even if the thickness of housing 510 and/or blocking member 512 is made thinner than when gap 515 is not formed.

As a modification of precursor 512A, precursors 612A and 712A of the blocking member shown in FIGS. 6(b) and (c) may be used. Precursor 612A includes a first cylindrical portion 612a, which is a short, bottomed cylinder, disposed at the end of housing precursor 610A; a second cylindrical portion 612b, which has a larger diameter than first cylindrical portion 612a; and a connecting portion 612c, which connects first cylindrical portion 612a and second cylindrical portion 612b. Connecting portion 612c is a cylindrical member whose diameter increases from the first cylindrical portion 612a side to the second cylindrical portion 612b side. Connecting portion 612c may have any shape as long as it connects first cylindrical portion 612a and second cylindrical portion 612b. For example, connecting portion 612c may be disk-shaped, forming precursor 612A in a stepped configuration. The precursor 712A includes a first cylindrical portion 712a with a bottom disposed at the end of the housing precursor 710A, a second cylindrical portion 712b with a short cylindrical shape and a diameter larger than that of the first cylindrical portion 712a, and a connecting portion 712c connecting the first cylindrical portion 712a and the second cylindrical portion 712b. The connecting portion 712c is a cylindrical member whose diameter increases from the first cylindrical portion 712a side to the second cylindrical portion 712b side. Note that the connecting portion 712c may have any shape as long as it connects the first cylindrical portion 712a and the second cylindrical portion 712b. For example, the connecting portion 712c may be disk-shaped, and the precursor 712A may be formed in a stepped shape. When using these modified precursors 612A and 712A, diameter reduction processing is easy. Furthermore, by providing connecting portion 612c that forms a step between first cylindrical portion 612a and second cylindrical portion 612b, and connecting portion 712c that forms a step between first cylindrical portion 712a and second cylindrical portion 712b, respectively, diameter reduction processing is performed in the portion indicated by the upper arrow in Fig. 6(b) and the portion indicated by the lower arrow in Fig. 6(c), whereby the formed reduced diameter portions (crimped portions) have a shape that conforms to connecting portion 612c, connecting portion 712c, and the holding force between the closing member (bottomed cylindrical member) and the housing is increased compared to when the above-described closing member 512 is employed. In other words, when precursors 612A, 712A are used instead of precursor 512A, it is possible to better prevent the closing member (bottomed cylindrical member) from falling off during activation of the gas generator.

The end of the coil spring 535 on the gas generating agent 531 side is configured to form a spiral plane, which also serves as a base for attaching the AI agent 532. The bypass prevention member 536 is fixed to the housing 510 via the welded portion 510c.

The first holder 520 is a generally cylindrical member made of resin, and has an annular groove 522 on its outer periphery. The first holder 520 is fixed to the housing 510 by reducing the diameter (by crimping, etc.) from the outer periphery of the housing 510 to the inside at a position corresponding to this annular groove 522, thereby forming a peripheral wall 510e.

The second holder 525 is a generally cylindrical metal member into which a portion of the igniter 550 (mainly the main body) is inserted, and part of its exterior is inserted into the first holder 520. The igniter 550 is fixed to the second holder 525 by crimping using the crimping portion 524. The second holder 525 is sandwiched between the first holder 520 and the third holder 555, and peripheral walls 510d and 510e (described below) are formed, thereby fixing the second holder 525 to the housing 510.

The third holder 555 is a generally cylindrical member made of resin, and has an annular groove 556 on its outer periphery. The third holder 555 is fixed to the housing 510 by narrowing (such as by crimping) the housing 510 from its outer periphery to its interior at a position corresponding to the annular groove 556, forming a peripheral wall 510d. A portion of the igniter 550 (mainly the squib cup 551) and the crimped portion 524 are inserted into the third holder 555. The third holder 555 is also a directional member that directs the direction of the flame generated in the igniter 550 toward the gas generating agent 531 when activated.

The igniter 550 is held and fixed to the housing 510 by these first holder 520, second holder 525, and third holder 555.

This embodiment not only achieves the same effects as the first embodiment, but also better prevents the blocking member 512 from falling off during operation.

Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration should not be considered limited to these embodiments. The scope of the present invention is indicated by the claims rather than the description of the above embodiments, and further includes all modifications within the meaning and scope of the claims.

For example, in the first to fourth embodiments, the gas generator may not be provided with a container. Furthermore, in the third and fourth embodiments, the gas generating agent may not be filled in the hollow portion of the filter. Furthermore, in the fifth embodiment, the bypass member may be eliminated, and the gas generating agent may be filled in the hollow portion of the filter.

In addition, in the first to fifth embodiments, the method of reducing the diameter of the housing was explained using crimping as an example, but any processing method that can reduce the diameter of the housing can be used.

10, 210, 310, 410, 510 Housing 10a, 10e, 210a, 310a, 310b, 310c, 310d, 310e, 410a, 510a, 510b, 510d, 510e Peripheral wall 11, 211, 311, 411, 511 Gas outlet 12, 212, 312, 412, 512 Closure member 12a, 212a, 312a, 412a, 512a Internal space 13, 22, 213, 313, 322, 413, 513, 514, 522, 556 Annular groove portion 20, 320 Holder 21, 23, 321, 323, 521, 523 Fitting portion 31, 331, 431, 531 Gas generating agent 32, 332, 532 AI agent 33, 333 Cover member 34, 334, 434 Container 34a, 334a, 434a Bottomed cylindrical portion 34b, 334b Lid portion 35, 54, 335, 535 Helical spring 36, 536 Bypass prevention member 41, 241, 341, 441, 541 Filter 41a, 241a, 341a, 441a, 541a Hollow portion 50, 350, 550 Igniter 51, 351, 551 Squib cup 52, 352, 552 Terminal pin 53 Approximately cylindrical member 100, 200, 300, 400, 500 Gas generator 212b, 412b Side portions 510A, 512A, 610A, 612A, 710A, 712A Precursor 515 Gap 520 First holder 525 Second holder 555 Third holder 612a, 712a First cylindrical portions 612b, 712b Second cylindrical portions 612c, 712c Joint portion

Claims (6)

a long cylindrical housing loaded with a gas generating agent that generates gas by burning, containing a filter therein through which the gas passes, and having a gas outlet formed at a position corresponding to the filter for ejecting the gas;
an igniter capable of igniting and burning the gas generating agent;
a holder that holds a portion of the igniter and is fixed to one axial end of the housing;
a blocking member fixed to the other axial end of the housing;
Equipped with
the closing member is a bottomed tubular member inserted partway into the housing from the other end of the housing, and the side surface of the bottomed tubular member is subjected to diameter reduction processing from the outside together with the housing at at least one location, thereby deforming the closing member together with the housing and fixing it to the housing ,
a closing member that closes the bottom of the cylindrical member after deformation and that closes the bottom of the cylindrical member after deformation, and that closes the bottom of the cylindrical member after deformation, and that closes the bottom of the cylindrical member after deformation . 2. The gas generator according to claim 1, wherein the bottomed tubular member is fixed to the housing by reducing the diameter of a side surface of the end of the bottomed tubular member together with the housing from the outside. the bottomed tubular member has a first tubular portion disposed on an end side of the housing, a second tubular portion having a diameter larger than that of the first tubular portion, and a connecting portion connecting the first tubular portion and the second tubular portion,
3. The gas generator according to claim 1, wherein at least one location where the diameter-reducing process is performed is located on the first cylindrical portion side of the connecting portion. 4. The gas generator according to claim 1, wherein the diameter-reducing process is performed at two or more locations. a long cylindrical housing loaded with a gas generating agent that generates gas by burning, containing a filter therein through which the gas passes, and having a gas outlet formed at a position corresponding to the filter for ejecting the gas;
an igniter capable of igniting and burning the gas generating agent;
a holder that holds a portion of the igniter and is fixed to one axial end of the housing;
a blocking member fixed to the other axial end of the housing;
Equipped with
the closing member is a bottomed tubular member inserted partway into the housing from the other end of the housing, and the side surface of the bottomed tubular member is subjected to diameter reduction processing from the outside together with the housing at at least one location, thereby deforming the closing member together with the housing and fixing it to the housing,
The diameter reduction process is performed at two or more locations,
a gas generator characterized in that, when the diameter reduction processing is performed at two or more locations, a gap is formed between the inner wall of the housing and the outer wall of the blocking member between adjacent locations of the diameter reduction processing. 6. The gas generator according to claim 5 , wherein the gap is formed by reducing the diameter of adjacent portions of the reduced diameter processed in the same process.