Gas generator

Abstract

To control a temperature of combustion gas being discharged.SOLUTION: A gas generator includes: a housing; an ignitor mounted at one end side of the housing; a combustion chamber; a cup-shaped diffuser part formed at the other end side, where the diffuser part includes a closed end formed at one end part, an open end formed at an opposite side of the closed end, and a lateral wall positioned between the closed end and the open end, has a housing space for housing a filter, and has a plurality of gas discharge holes; and a filter at least partially housed in the housing space so as to face the plurality of gas discharge holes, the filter extending from a side of the open end to a side of the closed end in the diffuser part and having a solid cooling part for cooling combustion gas of a gas generating agent. The plurality of gas discharge holes include first gas discharge holes at closer distances to the combustion chamber and second gas discharge holes at greater distances from the combustion chamber, with a total opening area of the first gas discharge holes and a total opening area of the second gas discharge holes being different.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Conventionally, there has been proposed a gas generator that includes a partition member and a partition portion that partition the internal space of a housing into a combustion chamber, a gas passage chamber, and a filter chamber (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-22929 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a gas generator, a filter is arranged opposite a plurality of gas exhaust holes, and combustion gas introduced from one end of the filter is exhausted from a plurality of gas exhaust holes at different distances from the end. In this case, the temperature of the combustion gas exhausted from each of the gas exhaust holes differs depending on the distance it has passed through the filter.

[0005] An object of the technique of the present disclosure is to provide a technique for controlling the temperature of exhausted combustion gas in a gas generator equipped with a cooling filter. [Means for solving the problem]

[0006] The gas generator of the present disclosure includes a housing forming an outer shell container, an ignition device attached to one end of the housing, a combustion chamber formed inside the housing and accommodating a gas generating agent, a cup-shaped diffuser portion formed on the other end of the housing, the diffuser portion including a closed end formed at one end, an open end formed on the opposite side of the closed end, and a sidewall located between the closed end and the open end, the open end being disposed to face the combustion chamber and an accommodating space formed inside for accommodating a filter, the diffuser portion having a plurality of gas discharge holes, and a filter at least a portion of which is accommodated in the accommodating space so as to face the plurality of gas discharge holes, the filter extending from the open end side of the diffuser portion toward the closed end side and having a solid cooling portion for cooling the combustion gas of the gas generating agent. The plurality of gas discharge holes are also comprised of one or more first gas discharge holes relatively close to the combustion chamber and a second gas discharge hole relatively close to the combustion chamber. 1 Or it includes one or more second gas exhaust holes that are relatively farther away than the multiple first gas exhaust holes, and the total opening area of ​​the one or more first gas exhaust holes is different from the total opening area of ​​the one or more second gas exhaust holes.

[0007] When a gas generator has a plurality of gas exhaust holes, the amount of combustion gas discharged per unit time from each of the gas exhaust holes varies depending on the area of ​​the gas exhaust hole. In the above-mentioned gas generator, the distance that the combustion gas passes through the cooling part of the filter varies depending on the distance from the combustion chamber to the gas exhaust hole, and the temperature of the combustion gas discharged from each of the gas exhaust holes varies accordingly. Therefore, by making the total opening area of ​​the first gas exhaust hole and the total opening area of ​​the second gas exhaust hole different, the ratio of the amount of combustion gas discharged from both can be changed, and the temperature of the combustion gas mixed therewith can be controlled.

[0008] Also, the one or more first gas discharge holes and the one or more second gas discharge holes may be provided in a side wall of the diffuser portion, and the filter may be disposed with no gap between the side wall of the diffuser portion and the filter. Such a filter has a larger volume and can improve the cooling effect of the combustion gas. It can be done.

[0009] Alternatively, the one or more first gas discharge holes and the one or more second gas discharge holes may be provided in a side wall of the diffuser section, and the filter may be tapered so that the diameter decreases from the open end side of the diffuser section toward the closed end side, and an annular gap may be formed between the filter and the side wall of the diffuser section. In this way, the flow of combustion gas is not concentrated in a portion of the filter facing the gas discharge holes, and the load on that portion can be reduced.

[0010] The total opening area of ​​the one or more second gas exhaust holes may be greater than the total opening area of ​​the one or more first gas exhaust holes. The combustion gas discharged from the second gas exhaust hole, which is relatively far away, passes through the filter the distance that is longer than that of the first gas exhaust hole. The length of the second gas exhaust hole is longer than the length of the combustion gas exhausted from the gas exhaust hole. By increasing the total opening area of ​​the second gas exhaust hole, a larger part of the filter can be used as a cooling section, and the temperature of the exhausted combustion gas can be lowered.

[0011] Furthermore, the one or more first gas exhaust holes and the multiple second gas exhaust holes may each have the same diameter, and the number of the multiple second gas exhaust holes may be greater than the number of the one or more first gas exhaust holes. Furthermore, the number of the one or more first gas exhaust holes may be the same as the number of the one or more second gas exhaust holes, and the opening area of ​​each of the one or more second gas exhaust holes may be greater than the opening area of ​​each of the one or more first gas exhaust holes. With this configuration, the total opening area of ​​the second gas exhaust holes can be made greater than the total opening area of ​​the first gas exhaust holes.

[0012] The filter may protrude from the open end of the diffuser toward the combustion chamber formed inside the housing, and an annular gap may be formed between the filter and the housing. In this way, the combustion gas flows into the filter not only from the end of the filter protruding toward the combustion chamber, but also from the gap formed between the filter and the housing. By widely dispersing the inflow points in this way, a wider area of ​​the filter can be efficiently used as a cooling section.

[0013] The filter may also be formed of a metal wire or a perforated plate, and a cooling portion for cooling the combustion gas can be formed from such materials.

[0014] The filter may have a through hole extending from the open end side to the closed end side of the diffuser portion. The filter may have such a through hole in addition to the cooling portion. Effect of the Invention

[0015] According to the present disclosure, it is possible to provide a technique for controlling the temperature of exhausted combustion gas in a gas generator equipped with a cooling filter. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic axial cross-sectional view showing an example of a gas generator according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of a cross section of a filter having a hole in the center. [Diagram 3] FIG. 3 is a diagram showing the results of a simulation of the relationship between the size of the gas exhaust hole and the temperature of the exhausted combustion gas. [Figure 4] FIG. 4 is a schematic partial axial cross-sectional view showing an example of a gas generator according to a second embodiment. [Diagram 5] FIG. 5 is a schematic partial axial cross-sectional view showing an example of a gas generator according to a third embodiment. [Figure 6] FIG. 6 is a partial side view showing an example of a gas generator according to the fourth embodiment. [Figure 7] FIG. 7 is a schematic partial axial cross-sectional view showing a modified example of the filter. [Figure 8] FIG. 8 is a diagram illustrating a schematic view of the flow of combustion gas in a filter according to a comparative example. [Figure 9] FIG. 9 is a diagram illustrating a schematic view of the flow of combustion gas within the filter according to the above-mentioned modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that each configuration and their combinations in each embodiment are merely examples, and addition, omission, substitution, 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.

[0018] <Embodiment 1> Fig. 1 is a schematic axial cross-sectional view showing an example of a gas generator according to this embodiment. The gas generator 1 can be used as a gas generating device for inflating an airbag, for example. The gas generator 1 in Fig. 1 includes a cylindrical housing 2, an ignition device 3 attached to one axial end side of the housing 2, and a diffuser portion 4 formed on the other end side of the housing 2.

[0019] The ignition device 3 is a device that is ignited by an ignition current, and is the same as that used in known gas generators. For example, the ignition device 3 has a metallic cup body 31 that contains and seals an ignition charge, and a pair of current-carrying pins 32, 32 for receiving a current supply from the outside, which are fixed to a metallic igniter holding part 33 with a resin member 34. The igniter holding part 33 of the ignition device 3 is attached to an opening on one axial end side of the housing 2, for example, by full-circumference welding.

[0020] The housing 2 is, for example, a cylindrical member having an approximately uniform inner diameter and outer diameter, and forms an outer shell container of the gas generator 1. The material of the housing 2 is, for example, a metal. A cup-shaped partition wall 5 is disposed inside the housing 2 at a predetermined distance from the ignition device 3.

[0021] In other words, the partition wall 5 is a bottomed cylindrical member, and the side includes a large diameter portion 51 having a large diameter and a small diameter portion 52 having a small diameter. The outer diameter of the large diameter portion 51 of the partition wall 5 is approximately the same as the inner diameter of the housing 2. Therefore, the housing 2 can accommodate the partition wall 5 so that the bottom portion 53 is located on the diffuser portion 4 side. The housing 2 and the outer periphery of the large diameter portion 51 may be welded to each other, or may be connected by an engagement portion (not shown) such as a projection and recess that engages with each other, which is provided on the inner periphery of the housing 2 and the outer periphery of the large diameter portion 51. In addition, one or more through holes 54 of a predetermined shape are formed in the bottom portion 53 of the partition wall 5. The through holes 54 allow the combustion products of the gas generating agent described later to pass through. A through hole may also be provided in the side portion of the small diameter portion 52 of the partition wall 5. Furthermore, the partition wall 5 divides the internal space of the housing 2 into a first combustion chamber 21 (also referred to as an "enhancer chamber") formed between the ignition device 3 and the partition wall 5, and a second combustion chamber 22 formed between the partition wall 5 and the diffuser portion. Note that the side portion (large diameter portion 51 or small diameter portion 52) of the partition wall 5 may be extended to an extent that the partition wall 5 and the ignition device 3 come into contact with each other, so that the partition wall 5 and the ignition device 3 form the first combustion chamber 21.

[0022] The first combustion chamber 21 accommodates a first gas generating agent 61 (also referred to as an "enhancer agent" or "enhancer"). The second combustion chamber 22 accommodates a second gas generating agent 62. The gas generating agents (the first gas generating agent 61 and the second gas generating agent 62) are, for example, guanidine nitrate (41 wt. %), basic copper nitrate (49% by weight), and binders and additives. The shape of each gas generating agent may be a single-hole cylindrical shape. However, the gas generating agent is not limited to the above. Furthermore, the first gas generating agent 61 and the second gas generating agent 62 may be gas generating agents of the same type, shape, and size, or may be gas generating agents of different types, shapes, and sizes.

[0023] The diffuser portion 4 is a cup-shaped member attached to close the other end of the housing 2, and accommodates the filter 7 therein. In other words, the diffuser portion 4 is a bottomed tubular member, and is disposed so that its open end faces the second combustion chamber 22. That is, the diffuser portion 4 has a side wall 41 and a closed end 42, and the open end side of the side wall 41, which is opposite to the closed end 42, is connected to the housing 2. In the example of FIG. 1, the outer diameter of the side wall 41 is approximately the same as the inner diameter of the housing 2, and a part of the open end side of the side wall 41 is accommodated in the housing 2. The open end side of the side wall 41 may be fixed to the housing 2 by caulking, or the diffuser portion 4 and the housing 2 may be welded together. The diffuser portion 4 may be formed integrally with the housing 2, for example, by drawing.

[0024] As shown in FIG. 1, one or more gas discharge holes 43 are formed in the side wall 41 of the diffuser section 4. The gas discharge holes 43 include a first gas discharge hole 431 (also referred to as a "first gas discharge hole group") and a second gas discharge hole 432 (also referred to as a "second gas discharge hole group"). The second gas discharge hole 432 may be provided in the closed end 42 instead of the side wall 41. In the example of FIG. 1, the second gas discharge hole 432 has a larger opening area than the first gas discharge hole 431. In addition, the number of the first gas discharge holes 431 and the number of the second gas discharge holes 432 are each one or more. In this embodiment, a plurality of the first gas discharge holes 431 and a plurality of the second gas discharge holes 432 are formed at equal intervals in the circumferential direction of the diffuser section 4, and the numbers of both are equal. Therefore, in this embodiment, the total opening area of ​​the second gas discharge holes 432 is larger than the total opening area of ​​the first gas discharge holes 431. Here, the "total opening area" refers to the sum of the opening areas of one or more gas discharge holes 43 (i.e., the sum of the opening areas of the gas discharge holes included in the first gas discharge hole group and the sum of the opening areas of the gas discharge holes included in the second gas discharge hole group). Also, the first gas discharge hole 431 and the second gas discharge hole 432 are provided at positions with different distances from the second combustion chamber 22. In the example of Fig. 1, the second gas discharge hole 432 is farther from the second combustion chamber 22 than the first gas discharge hole 431.

[0025] Moreover, an accommodation space for accommodating the filter 7 is formed inside the cup-shaped diffuser portion 4. At least a portion of the filter 7 is accommodated in the accommodation space of the diffuser portion 4. When the combustion gas generated by the gas generating agents 61, 62 passes through the filter 7, the filter 7 functions as a cooling portion for cooling the combustion gas, and also filters the combustion gas by collecting combustion residue of the combustion gas.

[0026] The filter 7 is cylindrical and extends from the open end side toward the closed end 42 side of the diffuser section 4, with the open end side protruding into the second combustion chamber 22. The surface of the filter 7 is accommodated so as to face the gas discharge hole 43 of the diffuser section 4. When the gas discharge hole 43 is provided in the closed end 42 of the diffuser section 4, the end face of the filter 7 on the closed end 42 side faces the gas discharge hole 43. The side surface of the filter 7 is in contact with the inner periphery of the side wall 41 of the diffuser section 4 so that the combustion gas passes through the filter 7.

[0027] For example, filter 7 may be formed by placing flat-woven metal wires in a mold and compressing them into a cylindrical shape. Filter 7 may also be formed by winding metal wires in multiple layers around a rod-shaped core material and forming a columnar shape with a mesh by crossing the wires. Filter 7 may also be formed by winding a sheet-like porous plate such as expanded metal, punched metal, metal lath, flat-woven wire mesh, or tatami-woven wire mesh into a cylindrical shape. It's fine.

[0028] As described above, the filter 7 is a metal filter having a solid cooling portion formed in a columnar shape. The metal may be stainless steel, iron, or the like, and may be plated or coated with copper, nickel, or the like. The term "solid" refers to the inclusion of a metal material at a predetermined density in order to collect the combustion residue of the combustion gas and cool the combustion gas. Therefore, a filter having an almost uniform density over the entire filter can be used, but the inside may not be completely solid and may include a gap in any part of the filter, or a recess may be formed on the end face of the filter, as long as the combustion gas passes through the filter at a different distance, allowing the temperature of the combustion gas to be adjusted.

[0029] The filter 7 protrudes from the diffuser portion 4 into the second combustion chamber 22. An annular gap 23 is formed between the filter 7 and the housing 2. Therefore, the combustion gas flows into the filter 7 not only from an end face 71 of the filter 7 in the protruding direction into the second combustion chamber 22, but also from the gap 23 side formed between the filter 7 and the housing 2 (from a tapered portion 72 described later). By making the filter 7 protrude significantly toward the second combustion chamber 22 side, the volume available as a cooling portion can be increased, and by widely dispersing the inflow points, a wide area of ​​the filter 7 can be efficiently used as a cooling portion.

[0030] The filter 7 may be tapered so that the diameter of the filter 7 decreases in the direction of protrusion toward the second combustion chamber 22. In the example of FIG. 1, the cross-sectional area of ​​the filter 7 decreases toward the end face 71, which is the end in the direction of the second combustion chamber 22, and a tapered portion 72 formed at an angle to the axial direction is provided around the end face 71. The tapered portion 72 angled with respect to the flow direction of the combustion gas makes it easier for the combustion gas to flow into the filter 7. On the other hand, the combustion gas flowing in from the side surface facing the gap 23 (the tapered portion 72 in the example of FIG. 1) travels a shorter distance through the inside of the filter 7 than the combustion gas flowing in from the end face 71, and there is a risk of unevenness in the degree of cooling and filtration depending on the point of inflow. To balance these factors and ensure a sufficient amount of inflow of the combustion gas from the end face 71, it is preferable to configure the filter 7 so that the surface area facing the gap 23 (the surface area of ​​the tapered portion 72 in the example of FIG. 1) is smaller than the surface area of ​​the end face 71 of the filter 7.

[0031] The filter 7 may have a hole of a predetermined diameter or less that penetrates from one end face to the other end face along the axial direction, for example, in a cross section perpendicular to the axial direction. FIG. 2 is a diagram showing an example of a cross section of a filter having a hole in the center. In the example of FIG. 2, the filter 7 has a through hole 73 along the axial direction, and a filter body 74 having an annular cross section around the through hole 73. The through hole 73 is formed, for example, by removing the above-mentioned core material after the filter 7 is formed. In this case, the filter body 74 functions as a solid cooling part. In order for the filter 7 to filter the combustion gas and function sufficiently as a cooling part, it is desirable for the cross-sectional area to satisfy the following formula. (cross-sectional area of ​​filter body 74 / (cross-sectional area of ​​filter body 74+cross-sectional area of ​​through hole 73))×100>50 The "50" on the right side of the formula represents, in percentage, the standard value that the ratio of the cross-sectional area of ​​the filter body 74 to the sum of the cross-sectional areas of the filter body 74 and the through-hole 73 must exceed. In other words, it is desirable that the cross-sectional area of ​​the filter body 74 is larger than the cross-sectional area of ​​the through-hole 73. If the end face of the filter on the side into which the gas flows is tapered (for example, the shape shown in FIG. 1), Taper Department Since this is the surface into which gas enters, the cross-sectional area of ​​the filter body is the cross-sectional area of ​​the portion indicated by the maximum diameter of filter body 74 on the surface into which gas flows in. The above reference value is more preferably "60", and even more preferably "75". That is, the cross-sectional area of ​​filter body 74 is more preferably a size exceeding 60% of the sum of the cross-sectional areas of filter body 74 and through-hole 73, and even more preferably a size exceeding 75%.

[0032] In addition, the second combustion chamber 22 is provided with an orifice plate 8 on the diffuser section 4 side and in the vicinity of the filter 7. The orifice plate 8 is a disk-shaped member having one or more through holes 81. The through holes 81 are blocked with a seal tape 82, and open when the internal pressure of the second combustion chamber 22 becomes equal to or higher than a predetermined value due to the combustion gas. Such an orifice plate 8 can maintain the airtightness of the combustion chambers 21, 22 before operation by connecting it to the housing 2, for example, by full-circumference welding. In this embodiment, the gas discharge hole 43 is not blocked. It is preferable that the total opening area of ​​the through holes 81 formed in the orifice plate 8 is smaller than the sum of the opening areas of the first gas discharge hole 431 and the second gas discharge hole 432, because this creates a choke for the combustion gas and allows the flow rate to be adjusted. In addition, instead of the orifice plate 8 and the seal tape 82, a canister formed of a metal film such as aluminum or other configuration may be used to keep the gas generating agent airtight.

[0033] <Operation> When the gas generator 1 is mounted on, for example, an airbag of an automobile, a connector (not shown) is connected to a pair of current-carrying pins 32, 32, and power can be supplied to the ignition device 3. In this state, when a sensor (not shown) mounted on the automobile or the like detects an impact, the ignition device 3 is actuated by an ignition current supplied to the pair of current-carrying pins 32, 32. The ignition device 3 burns the ignition charge in the cup body 31 and releases the combustion product to the outside of the cup body 31. The first gas generating agent 61 is ignited by the flame and gas that are the combustion products of the ignition charge. The first gas generating agent 61 generates combustion gas as a combustion product, and the combustion gas passes through the through hole 54 of the partition wall 5 to ignite the second gas generating agent 62 in the second combustion chamber 22. The second gas generating agent 62 also generates combustion gas as a combustion product. When the sealing tape 82 of the orifice plate 8 is torn by the pressure of the combustion gas in the second combustion chamber 22, the combustion gas passes through the through holes 81 and the filter 7, is filtered and cooled, and is discharged from the gas discharge hole 43 of the diffuser section 4.

[0034] <Effects> When the internal pressure of the gas generator 1 is sufficiently high, the amount of combustion gas discharged from the first gas discharge hole 431 per unit time The ratio of the amount of the combustion gas discharged from the first gas discharge hole 431 to the amount of the combustion gas discharged from the second gas discharge hole 432 per unit time corresponds to the ratio of the area of ​​the first gas discharge hole 431 to the area of ​​the second gas discharge hole. Also, the temperature of the combustion gas discharged from the first gas discharge hole 431 and the temperature of the combustion gas discharged from the second gas discharge hole 432 are cooled according to the distance from the second combustion chamber 22 to each gas discharge hole (i.e., the distance the combustion gas passes through the filter 7). Therefore, the combustion gas discharged from the gas generator 1 has a temperature obtained by mixing the combustion gas discharged from the first gas discharge hole 431 and the combustion gas discharged from the second gas discharge hole 432, and the temperature can be adjusted by the size of the first gas discharge hole 431 and the size of the second gas discharge hole.

[0035] FIG. 3 is a diagram showing the results of a simulation of the relationship between the size of the gas discharge hole and the temperature of the discharged combustion gas. The horizontal axis of FIG. 3 indicates the diameter of the first gas discharge hole 431 on the upstream side. The diameter of the second gas discharge hole 432 on the downstream side was changed according to the diameter of the first gas discharge hole 431, and the total opening area of ​​the first gas discharge hole 431 and the second gas discharge hole 432 was made equal. The vertical axis of FIG. 3 indicates the temperature of the discharged combustion gas. The points plotted on the graph indicate the temperature when the temperature of the combustion gas discharged from the first gas discharge hole 431 and the temperature of the combustion gas discharged from the second gas discharge hole 432 are combined. As can be seen from FIG. 3, the smaller the first gas discharge hole 431 on the upstream side is made (i.e., the larger the second gas discharge hole 432 on the downstream side is made), the lower the temperature of the discharged combustion gas. The coefficient of determination R of the model equation shown by a straight line in FIG. 3 2 As described above, when the downstream second gas discharge hole 432 is enlarged, the amount of gas passing through the part of the filter 7 on the closed end 42 side of the diffuser portion 4 is increased. Since the amount of combustion gas increases, the combustion gas passes through a relatively long distance in the filter at a higher rate. In other words, the filter 7 can function sufficiently as a cooling part. On the other hand, by enlarging the first gas discharge hole 431 on the upstream side, the combustion gas passes through a relatively short distance in the filter at a higher rate. Therefore, the temperature of the combustion gas can be increased.

[0036] <Embodiment 2> FIG. 4 is a schematic partial axial cross-sectional view showing an example of a gas generator according to a second embodiment. In this embodiment, the diffuser portion 4 is different from the embodiment in FIG. 1. The same components as those in the first embodiment described above are given the corresponding reference numerals or are not shown in the drawings.

[0037] 4, the area of ​​the first gas discharge hole 431 closer to the second combustion chamber 22 is larger than the area of ​​the second gas discharge hole 432 farther from the second combustion chamber 22. With such a configuration, the proportion of combustion gas that travels a short distance through the filter 7 increases, and high-temperature combustion gas is discharged. For example, when the gas generator 1 is assembled to an airbag, this can promote early deployment of the airbag and improvement of output.

[0038] <Embodiment 3> 5 is a schematic partial axial cross-sectional view showing an example of a gas generator according to a third embodiment. In this embodiment, only the diffuser portion 4 is different from the embodiment in FIG. The same components as those in the above-described embodiment are denoted by corresponding reference numerals or are omitted from the illustration.

[0039] The diffuser section 4 in FIG. 5 includes three gas discharge holes 431-433 (three gas discharge hole groups) that are different in distance from the second combustion chamber 22. In the example in FIG. 5, the opening area increases from the upstream side to the downstream side in the flow direction of the combustion gas. In the present embodiment, the number of gas discharge holes included in each gas discharge hole group is the same. The opening area may decrease from the upstream side to the downstream side in the flow direction of the combustion gas. As described above, the distance from the second combustion chamber 22 and the opening area may be differentiated in three or more stages. Even in such an example, the temperature of the entire combustion gas discharged from the gas generator 1 can be adjusted by setting a predetermined magnitude relationship in the total opening area of ​​any first gas discharge hole close to the second combustion chamber 22 and any second gas discharge hole far from the second combustion chamber 22. In the example of FIG. 5, the combination of gas exhaust hole 431 and gas exhaust hole 432, the combination of gas exhaust hole 432 and gas exhaust hole 433, and the combination of gas exhaust hole 431 and gas exhaust hole 433 correspond to combinations of a "first gas exhaust hole" and a "second gas exhaust hole" according to the present disclosure, and have a predetermined size relationship with respect to the total opening area.

[0040] <Embodiment 4> 6 is a partial side view showing an example of a gas generator according to a fourth embodiment. In this embodiment, only the diffuser portion 4 is different from the embodiment shown in FIG. The same components as those in the embodiment are denoted by corresponding reference numerals or are omitted from the illustration.

[0041] The diffuser section 4 in FIG. 6 includes two gas discharge holes 431, 432 (gas discharge hole groups) that are different in distance from the second combustion chamber 22. However, the size of each gas discharge hole is the same, and the number of the first gas discharge holes 431 is smaller than the number of the second gas discharge holes 432. In other words, the number of gas discharge holes belonging to the first gas discharge hole group is smaller than the number of gas discharge holes belonging to the second gas discharge hole group. In the case of this embodiment as well, the total opening area of ​​the first gas discharge holes 431 is smaller than the total opening area of ​​the second gas discharge holes 432. The relationship of the size of the total opening areas may be reversed. Even in such an example, the temperature of the combustion gas discharged from the gas generator 1 can be adjusted.

[0042] <Modifications of Filter> 7 is a schematic partial axial cross-sectional view showing a modified example of the filter. In this embodiment, the diffuser portion 4 and the filter 7 are also different from those in the embodiment shown in FIG. The same components as those in the embodiment are denoted by corresponding reference numerals or are omitted from the illustration.

[0043] In the example of FIG. 7, the filter 7 is tapered on the side of the closed end 42, and the cross-sectional area of ​​the transverse section becomes smaller toward the closed end. That is, in the example of FIG. 7, an annular gap 44 is formed between the diffuser section 4 and the filter 7. Note that the side of the filter 7 is in contact with the inner circumference of the side wall 41 of the diffuser section 4 at least on the open end side so that the combustion gas passes through the filter 7. The side of the filter 7 may also be tapered on the open end side. The filter 7 of FIG. 7 is also accommodated in the accommodation space of the diffuser section 4 so as to face the gas discharge holes 43. That is, the filter 7 extends from the open end to the closed end 42 of the diffuser section 4, and the filter 7 has a surface facing each of the gas discharge holes 43. Therefore, in this embodiment as well, the combustion gas is cooled according to the distance it has passed through the filter 7, and is discharged from the gas discharge holes 43.

[0044] Fig. 8 is a diagram showing a schematic diagram of the flow of combustion gas in a filter according to a comparative example. The combustion gas introduced into the filter 7 tends to flow the shortest distance toward the gas discharge hole 43. Therefore, when there is no space between the filter 7 and the diffuser portion 4 as shown in Fig. 8, the combustion gas does not easily flow through the portion of the filter 7 that does not face the gas discharge hole 43. In the example of Fig. 8, the portion indicated by the triangle does not fully perform the cooling function.

[0045] Fig. 9 is a diagram showing a schematic diagram of the flow of combustion gas in the filter according to the above-mentioned modified example. When the annular gap 44 is formed, the combustion gas flows out smoothly from the filter 7 through the annular gap 44 as shown in Fig. 9. Therefore, compared to the comparative example in Fig. 8, the volume and weight of the filter 7 are reduced, but the area where the cooling function is not fully performed because the flow of the combustion gas is difficult to occur is reduced.

[0046] Furthermore, for example, if the filter 7 is made of a wire, when the combustion gas passes through the filter 7 and is discharged, the wire may fray on the outer periphery of the filter 7, causing fragments of the wire to be released from the gas discharge hole 43. In particular, when many of the side surfaces of the filter 7 are in contact with the side wall 41 of the diffuser portion 4 as shown in FIG. 1 etc., the flow of the combustion gas is concentrated in the portion of the side surface of the filter 7 facing the gas discharge hole 43, making it easy for the wire to fray partially. On the other hand, if an annular gap 44 is formed between the diffuser portion 4 and the filter 7 as shown in FIG. 7, the portion through which the combustion gas flows can be dispersed, and the occurrence of fraying can be reduced.

[0047] On the other hand, if the filter 7 is disposed without any gap between it and the side wall 41 of the diffuser portion 4 as shown in FIG. 8, the volume of the filter 7 becomes larger, and the cooling effect of the combustion gas can be improved.

[0048] <Other> The above is a gas generation method according to the present disclosure. vesselAlthough the above embodiment has been described, each aspect disclosed in this specification may be combined with other features disclosed in this specification. Also, the gas generator 1 may be incorporated in a device other than an airbag.

[0049] 1, 4 to 7, and 9 show examples in which the opening area of ​​each of the gas discharge holes 43 increases or decreases monotonically from the upstream side to the downstream side in the flow direction of the combustion gas, or the number of the gas discharge holes 43 increases or decreases monotonically from the upstream side to the downstream side, but the present invention is not limited to such examples. That is, in a gas generator in which gas flows in the axial direction of the filter, it is sufficient that the cooling degree can be adjusted by making a difference between the amount of gas flowing only on the upstream side of the filter and discharged and the amount of gas flowing to the downstream side and discharged. For example, it is sufficient that the opening ratio of the gas discharge holes relative to the surface area of ​​the diffuser portion is different between the upstream side and the downstream side in the flow direction of the combustion gas. In this case, too, it can be said that the total opening area of ​​the first gas discharge holes provided on the upstream side is different from the total opening area of ​​the second gas discharge holes provided on the downstream side. In addition, the gas discharge hole The shape of 43 is also not limited to a circle, and may be, for example, a hole that is long in the circumferential direction in the side wall 41 of the diffuser section 4, or a hole that is long in the axial direction of the housing 2, and may be a shape other than a circle or an ellipse, such as a square or rectangle. [Explanation of symbols]

[0050] 1: Gas generator 2: Housing 21: First combustion chamber 22: Second combustion chamber 23: Gap 3:Ignition device 31: Cup body 32: Power pin 33:Igniter holding part 34: Resin material 4: Diffuser section 41: Side wall 42: Closed end 43: Gas exhaust hole 431: First gas exhaust hole 432: Second gas exhaust hole 44:Gap 5: Bulkhead 51: Large diameter section 52: Small diameter part 53: Bottom 54:Through hole 61: First gas generator 62: Second gas generator 7: Filter 71: End face 72: Tapered section 73:Through hole 8: Orifice plate 81:Through hole 82: Sealing tape

Claims

1. a housing forming an outer shell; an ignition device attached to one end side of the housing; a combustion chamber formed within the housing and configured to accommodate a gas generating agent; a cup-shaped diffuser portion formed on the other end side of the housing, the diffuser portion including a closed end formed on one end, an open end formed on the opposite side of the closed end, and a sidewall located between the closed end and the open end, the open end being disposed so as to face the combustion chamber, an accommodation space for accommodating a filter being formed inside the diffuser portion, and the diffuser portion having a plurality of gas discharge holes; a filter, at least a portion of which is accommodated in the accommodation space so as to face the plurality of gas discharge holes, the filter extending from the open end side of the diffuser portion toward the closed end side, and having a solid cooling portion which protrudes from the open end of the diffuser portion into the combustion chamber so that the combustion gas of the gas generating agent flows in from the open end of the filter, and which cools the combustion gas; Equipped with The plurality of gas exhaust holes include one or more first gas exhaust holes that are relatively close to the combustion chamber, and one or more second gas exhaust holes that are relatively farther from the combustion chamber than the one or more first gas exhaust holes. one or more second gas exhaust holes, and a total opening area of ​​the one or more first gas exhaust holes is different from a total opening area of ​​the one or more second gas exhaust holes. Gas generator.

2. the one or more first gas exhaust holes and the one or more second gas exhaust holes are provided in the side wall of the diffuser portion, The filter is disposed with no gap between the filter and the side wall of the diffuser portion.

2. The gas generator according to claim 1.

3. the one or more first gas exhaust holes and the one or more second gas exhaust holes are provided in the side wall of the diffuser portion, The filter is formed with a taper that reduces in diameter from the open end side to the closed end side of the diffuser portion, and a contact between the filter and the side wall of the diffuser portion is formed. With an annular gap between 2. The gas generator according to claim 1.

4. A total opening area of ​​the one or more second gas exhaust holes is larger than a total opening area of ​​the one or more first gas exhaust holes. A gas generator according to any one of claims 1 to 3.

5. The one or more first gas exhaust holes and the plurality of second gas exhaust holes have the same diameter, and the number of the plurality of second gas exhaust holes is greater than the number of the one or more first gas exhaust holes.

5. The gas generator according to claim 4.

6. The number of the one or more first gas exhaust holes is the same as the number of the one or more second gas exhaust holes, and an opening area of ​​each of the one or more second gas exhaust holes is larger than an opening area of ​​each of the one or more first gas exhaust holes.

5. The gas generator according to claim 4.

7. The filter has an annular gap between the filter and the housing. A gas generator according to any one of claims 1 to 6.

8. The filter is formed of a metal wire or a perforated plate. A gas generator according to any one of claims 1 to 7.

9. The filter has a through hole extending from the open end side to the closed end side of the diffuser portion. A gas generator according to any one of claims 1 to 8.

10. a housing forming an outer shell; an ignition device attached to one end side of the housing; a combustion chamber formed within the housing and configured to accommodate a gas generating agent; a diffuser portion formed on the other end side of the housing, the diffuser portion having an accommodation space for accommodating a filter therein and a plurality of gas exhaust holes; a filter, at least a portion of which is accommodated in the accommodation space so as to face the plurality of gas discharge holes, and which is provided protruding from the diffuser portion into the combustion chamber so that the combustion gas of the gas generating agent flows in; Equipped with the plurality of gas exhaust holes include one or more first gas exhaust holes that are relatively close to the combustion chamber and one or more second gas exhaust holes that are relatively farther from the combustion chamber than the one or more first gas exhaust holes, and a total opening area of ​​the one or more first gas exhaust holes is different from a total opening area of ​​the one or more second gas exhaust holes; Gas generator.

11. The filter has an end face in a protruding direction toward the combustion chamber and a combustion chamber side taper that narrows toward the end face, The surface area of ​​the combustion chamber side taper is smaller than the surface area of ​​the end surface. A gas generator according to any one of claims 1 to 10.

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