JP3029968U - Gas generator for airbag - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a gas generator that can sufficiently meet the demands for downsizing and weight reduction. SOLUTION: A boundary wall member (22) corresponding to one wall of the combustion chamber G is arranged at the boundary between the combustion chamber G and the filter chamber F, and the boundary wall member (22) has a right cylindrical shape. A metal tubular member having a double pipe structure having a bottom portion (22c) between the outer tubular wall (22b) and the inner tubular wall (22d), wherein the inner tubular wall length is shorter than the outer tubular wall length, Further, the outer cylindrical wall (22b) of the tubular member is provided with a plurality of openings (22a) in the circumferential direction, and the bottom (22) of the tubular member is provided.
c) crawls on the lower lid 21, and the inner cylinder wall (22d) corresponding to the axial center side tip of the bottom (22c) is the inner cylindrical wall (4) of the upper container (2) formed at the time of butt welding. The flash (4b) is urged against and fixed to the flash (4b), and the surface pressure effect enhances the sealing property of the combustion chamber G so that the combustion pressure can be adjusted accurately.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

 The present invention relates to a gas generator for inflating an airbag, which is a vehicle occupant protection device.

[0002]

[Prior art]

 This type of conventional gas generator is disclosed in U.S. Pat. No. 454734 (hereinafter referred to as "first conventional example"). The structure will be briefly described with reference to FIG. 3. The gas generator includes a triple short cylindrical container 1 having an inner cylinder 4, an intermediate cylinder 5 and an outer cylinder 6, and the inside of the container 1 is An ignition chamber 7 is formed in the cylinder 4, a gas generation chamber G is formed between the inner cylinder 4 and the intermediate cylinder 5, and a filter chamber F is formed between the intermediate cylinder 5 and the outer cylinder 6. Further, the inner cylinder 4 has a first gas hole 4a. The intermediate cylinder 5 has a second gas hole 5a, and the outer cylinder 6 has a gas discharge hole 6a. The squib 9 and the transfer charge 10 constitute an ignition means. The gas generating agent G and the first filter 12 are sequentially stored in the gas generating chamber G 1 in the radial direction, and the deflector plate 13, the second and third filters 14 and 15 are sequentially stored in the filter chamber F 1. The deflector plate 13 has its upper end bent and abuts against the upper surface inside the container 1, thereby providing a sealing property, while the lower end has a gas hole 13a.

When the transfer charge 10 is ignited, its hot air (arrow) flows into the gas generating chamber G through the first gas holes 4a, and the gas generating agent 11 reacts to generate a high-temperature gas containing slag. appear. Further, this gas passes through the first filter 12 and flows into the filter chamber F from the second gas hole 5a, hits the deflector plate 13, and travels downward. Further, the gas that has passed through the gas holes 13a of the deflector plate 13 ascends along the second filter 14 and then passes through the second filter 14 and the third filter 15, during which the cooling of gas and the collection of slag are performed. Done. Then, finally, an appropriate temperature and clean gas is supplied to the inside of the airbag (not shown) through the gas discharge holes 6a.

Further, the one described in Japanese Utility Model Laid-Open No. 5-74620 (second conventional example) is known (see FIG. 4). Comparing the first conventional example with a particular focus on the action surface, 12 of the first conventional example corresponds to 17 of the second conventional example, and 5 of the first conventional example of 16 corresponds to the second conventional example of 16. In addition, 14 and 15 of the first conventional example correspond to 18 and 19 of the second conventional example.

[0005]

[Problems to be solved by the device]

 However, in the case of the first conventional example (see FIG. 3), the filter structure is a multi-layer of the first filter 12, the deflector plate 13, the second filter 14, and the third filter 15, which makes the gas generator larger than necessary. However, there is a problem that the weight increases. Also, in the case of the second conventional example (see FIG. 4), it can be said that almost the same as the consideration in the first conventional example. That is, since the filters 17, 18 and 19 are provided, the filters are increased in size due to the large amount of use, and an increase in weight is inevitable. Furthermore, since the boundary wall member 16 has a complicated shape and is not suitable for press molding, there is a problem that the manufacturing cost is high.

The present invention has been completed as a result of intensive studies to solve such problems of the conventional technology. The purpose of the present invention is to sufficiently meet the demands for downsizing and weight reduction. It is to provide a gas generator.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, the invention according to claim 1 is the inner cylindrical wall (4), the outer cylindrical wall (6), the inner and outer cylindrical walls (4, 6) and the inner cylindrical wall (4). An upper container (2) having an upper lid (20) extending therein; and a lower lid (2) extending between the inner cylindrical wall (7), the outer cylindrical wall (8) and at least the inner and outer cylindrical walls (7, 8). 21) and the lower container (3) having the above are friction welded by abutting the two ends of the inner cylindrical walls (4, 7) and the outer cylindrical walls (6, 8). Define a central space (30) and a concentric annular space (40). The central space (30) is an ignition chamber P composed of a squib (9) and an ignition agent (10), and the annular space (40) is , A combustion chamber G in which the gas generating agent (11) is housed in order from the side of the central space (30) toward the outer side in the radial direction, the cooling / slag of the combustion gas In the gas generator for an air bag provided with a filter chamber F for collecting gas, and openings (4a, 6a, 22a) for releasing gas which communicate these chambers (P, G, F), the combustion chamber G A boundary wall member (22) corresponding to one wall of the combustion chamber G is disposed at the boundary between the filter chamber F and the filter chamber F, and the boundary wall member (22) is formed into a right cylindrical outer cylinder wall (22 b). And a metal tubular member having a double pipe structure having a bottom portion (22c) between the inner tubular wall (22d) and the inner tubular wall length being shorter than the outer tubular wall length. A plurality of openings (22a) are provided on the outer cylindrical wall (22b) of the outer peripheral wall of the cylindrical member, the bottom portion (22c) of the cylindrical member crawls on the lower lid 21, and the tip of the bottom portion (22c) on the axial center side. The inner cylinder wall (22d) corresponding to the part is formed on the upper container (2) at the time of butt welding. Contact is allowed to bias the burr (4b) of the inner cylindrical wall (4), characterized in that the fixing.

Here, “a metal tubular member having a double-tube structure having a bottom portion (22 c) between the outer cylindrical wall (22 b) and the inner cylindrical wall (22 d) having a right cylindrical shape” means 1 in principle. This means that a short tubular member having a bottom with a central hole is formed by pressing, and there are no special limiting conditions for the dimensional ratio of the tubular wall and the bottom or the shape of the peripheral edge on the central hole side. . It is also possible to adopt a structure in which the cylindrical wall and the bottom are made of different materials and welded to each other, but it is advantageous to use an integral press-formed product in terms of processing cost.

Further, the position of the opening provided in the cylindrical wall is not particularly limited, but it is preferably provided at a position apart from the final gas releasing opening in the axial direction. By doing so, the ignition flame is located at a position axially separated from the opening that flows into the combustion chamber, which is more advantageous in terms of complete combustion of the gas generant, and in order to obtain a sufficient filter effect, it is also advantageous. This is because it is preferable to increase the contact area.

According to the above configuration, the filter chamber for gas cooling / slag collection need only be attached to the inner peripheral surface of the outer wall of the container, and the size and weight can be reduced accordingly. Moreover, since the boundary wall member can be obtained by one press molding, it is inexpensive. Furthermore, since the tip of the bottom of the boundary wall member is fixed by abutting against the burr of the inner cylindrical wall formed during butt welding so as to urge it, the surface pressure effect of the combustion chamber G The sealability can be improved. Therefore, the combustion pressure can be adjusted accurately.

Further, in the invention according to claim 2, the front end portion of the inner cylindrical wall (22d) of the boundary wall member (22) is bent toward the bottom portion (22c), and the flash (4b) of the inner cylindrical wall (4). It is characterized in that it is abutted and fixed so as to be urged to. In this way, by making the cross-sectional shape of the tip of the inner cylindrical wall a so-called hook shape, the gas generating agent is completely isolated from the high temperature flash formed at the joint during friction welding, and the gas generating agent is It is possible to effectively prevent the occurrence of a situation such as spontaneous combustion. The tip of the inner cylinder wall may be fixed by urging abutment against the flash so that the tip surface of the tip may contact the surface of the flash, or at a position slightly retracted from the tip surface. The peripheral surface of the tip of the inner cylinder wall may contact the surface of the flash.

[0012]

[Embodiment of device]

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing the configuration of the gas generator according to the embodiment. The same components as those in the first conventional example (FIG. 3) and the second conventional example (FIG. 4) are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 1, the gas generator has an ignition chamber P, a combustion chamber G, and a filter chamber F arranged in this order from the center of the shaft in the radial direction, and the chambers are connected by openings. A boundary wall member 22 corresponding to one wall of the combustion chamber G is arranged at the boundary between the combustion chamber G and the filter chamber F, and the boundary wall member 22 includes a straight cylindrical outer cylinder wall 22b and a straight cylindrical wall 22b. It is a metal tubular member having a double pipe structure having a bottom portion 22c between the inner cylindrical walls 22d having a truncated cone shape, and the inner tubular wall length is shorter than the outer tubular wall length. Further, the outer cylindrical wall 22b of the cylindrical member is provided with a plurality of openings 22a in the circumferential direction. Further, the bottom portion 22c of the tubular member crawls on the lower lid 21, and the inner cylindrical wall 22d corresponding to the tip end on the axial center side of the bottom portion 22c has the inner cylindrical wall 4 of the upper container 2 formed during butt welding. It is fixed by abutting against the flash 4b. Reference numeral 25 is a thin film container made of aluminum or the like in which the gas generating agent 11 is hermetically sealed, which is manufactured under a design condition such that the gas generating agent 11 breaks when a predetermined pressure acts in advance.

The boundary wall member 22 described above can be easily obtained by unidirectional pressing. Further, due to the shape, when the combustion pressure is applied to the combustion chamber G, the outer cylinder wall 22b is apt to be deformed in the constituent portion having the shape from the bottom portion 22c to the cylindrical wall 22d at the tip end on the axial center side. The force acts in the direction of resisting the force. Therefore, even if the intermediate cylinder (combustion wall) 5 having a thick structure is not used as in the first conventional example (FIG. 3), the complicated shape that is difficult to press as in the second conventional example (FIG. 4) is used. It is not necessary to use the boundary wall member 16. Therefore, the manufacturing cost and weight of the gas generator can be reduced.

In the gas generator configured as described above, when the squib 9 is ignited, the transfer charge 10 is ignited by this ignition and heat is generated, and the hot air passes through the opening 4 a and breaks the sealed container 25. , Reaches the gas generant 11 (arrow). Then, the gas generating agent 11 is burned by this heat to generate a large amount of gas. When the container 25 reaches the above-mentioned predetermined pressure, the container 25 bursts and the generated gas exits from the opening 22a.

At the time of combustion, the inner cylinder wall 22d is further strongly pressed against the flash 4b by the combustion pressure, which has the effect of further enhancing the surface pressure effect. Therefore, due to the synergistic effect of this action, the sealing property between the boundary wall member 22 and the inner cylinder 4 is maintained almost perfectly. As a result, the combustion pressure can be adjusted exactly as set, and the gas generant can be combusted without excess or deficiency.

The gas that has passed through the opening 22a is cooled to an appropriate temperature while passing through the filter chamber F as shown by the arrow, and after being cleaned by removing the slag, the inside of the airbag (not shown) is opened through the opening 6a. Is released to. As described above, as the structure for cooling the gas and collecting the slag after combustion, the filter 50 is simply arranged along the inner peripheral surface of the outer cylinder 6.

Therefore, the first filter 12, the deflector plate 13, the second filter 14, the third filter 15 in the first conventional example (FIG. 3) and the filters 17, 18, in the second conventional example (FIG. 4), It occupies less volume and weight than the construction according to 19 and saves material. From this aspect as well, the manufacturing cost of the gas generator can be reduced, and the size and weight can be reduced.

When assembling the gas generator, if there is a concern that the high-temperature state flash formed in the joint during friction welding may affect the gas generating agent, the following means is effective. It That is, as shown in FIG. 2 (a cross-sectional view of the main part), the tip of the inner cylindrical wall 22d of the boundary wall member 22 is bent toward the bottom 22c and brought into contact with the flash 4b of the inner cylindrical wall 4 so as to urge it. And fix it. In this way, by making the cross-sectional shape of the tip end portion of the inner cylindrical wall 22d into a so-called hook shape, the gas generating agent 11 is removed from the high temperature state burr (4b, 7b) formed at the joint portion during friction welding. By completely isolating the gas generator 11, it is possible to effectively prevent a situation in which the gas generating agent 11 spontaneously ignites.

[0020]

[Effect of device]

 As described above, the invention according to claim 1 of the present invention is, in short, a structure in which the sealing property of the combustion chamber is further enhanced and the combustion pressure can be accurately adjusted while using the metal press-molded member. As a result, it has become possible to provide a gas generator that can sufficiently meet the demands for further size reduction and weight reduction, together with the simplification of the filter chamber. In addition, since the invention of claim 2 is configured such that the gas generating agent is sufficiently isolated from the high temperature flash when assembling the gas generator, in addition to the effect of the invention of claim 1, It is now possible to provide a gas generator that is fully considered in terms of safety so that the gas generant does not spontaneously ignite when the generator is assembled.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a gas generator according to an embodiment of the present invention.

FIG. 2 is a main-portion cross-sectional view showing a modified example of a boundary wall member.

FIG. 3 is a cross-sectional view showing a configuration of a gas generator of a first conventional example.

FIG. 4 is a cross-sectional view showing a configuration of a gas generator of a second conventional example.

[Explanation of symbols]

 4 Inner cylindrical wall 4b Burr 6 Outer cylindrical wall 21 Lower lid 22 Boundary wall member F Filter chamber G Combustion chamber P Ignition chamber

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsuyoshi Kanda 3903-39, Abundant Town, Himeji City, Hyogo Prefecture Nihon Kayaku Co., Ltd. Himeji Factory Sensor Technology Co., Ltd. Himeji Technical Center (72) Inventor Koji Tanaka 3903-39 Abundant, Toyotomi-cho, Himeji-shi, Hyogo Nihon Kayaku Co., Ltd. Himeji Factory, Sensor Technology Co., Ltd., Himeji Technical Center (72) Inventor Nobuaki Yokote 3903-39 Abundant Abundant Town, Himeji-shi, Hyogo Nihon Kayaku Co., Ltd. Company Himeji Factory Sensor Technology Co., Ltd. Himeji Technical Center (72) Inventor Takashi Sosou 3903-39 Abundant Town, Himeji City, Hyogo Prefecture Nippon Kayaku Co., Ltd. Himeji Factory Sensor Technology Co., Ltd. Himeji Technical Center Uchi (72) Creator Miyamoto Hisashi Ibaraki Prefecture, Shinji-gun Chiyoda-cho, Kamiinayoshi Mukaihara 1764-1 Sensor Technology Co., Ltd. Tsukuba business premises (72) inventor of Satoshi Yanai Ibaraki Prefecture, Shinji-gun Chiyoda-cho, Kamiinayoshi Mukaihara 1764-1 Sensor Technology Co., Ltd. Tsukuba business premises

Claims (2)

[Scope of utility model registration request] 1. An upper container (2) having an inner cylindrical wall (4), an outer cylindrical wall (6), inner and outer cylindrical walls (4, 6) and an upper lid (20) extending into the inner cylindrical wall (4). ), And a lower container (3) having an inner cylindrical wall (7), an outer cylindrical wall (8) and a lower lid (21) extending at least between the inner and outer cylindrical walls (7, 8), Two points, that is, the tips of the walls (4, 7) and the tips of the outer cylindrical walls (6, 8) are butted against each other and friction welded to define a central space (30) and a concentric annular space (40). , The central space (30) is an ignition chamber P including a squib (9) and an igniting agent (10), and the annular space (40) is a gas generating agent (in order from the central space (30) side toward the radial outside). Combustion chamber G, in which 11) is housed,
A filter chamber F for cooling combustion gas and collecting slag,
In an airbag gas generator provided with openings (4a, 6a, 22a) for releasing gas, which communicate with each of these chambers (P, G, F), combustion is carried out at the boundary between the combustion chamber G and the filter chamber F. Boundary wall member (22) corresponding to one wall of the chamber G
And the bottom wall (22) between the outer cylinder wall (22b) and the inner cylinder wall (22d) having a right cylindrical shape.
c) a double-tube-structured metal tubular member having an inner tubular wall length shorter than an outer tubular wall length, and the outer tubular wall (22b) of the tubular member has a circumferential direction. A plurality of openings (22a) are provided throughout, and the bottom portion (22c) of this tubular member crawls on the lower lid 21, and further the bottom portion (22c).
The inner cylindrical wall (22d) corresponding to the axial center side end of c) is brought into contact with the burr (4b) of the inner cylindrical wall (4) of the upper container (2) formed at the time of butt welding so as to be biased. A gas generator for airbags that is fixed. 2. The inner cylindrical wall (22) of the boundary wall member (22).
The gas generation for an air bag according to claim 1, wherein the front end portion of (d) is bent toward the bottom portion (22c) and abutted and fixed so as to urge it against the burr (4b) of the inner cylindrical wall (4). vessel.