JPH10324220A - Gas generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need for frequently designing and producing a filter member according to size of a gas generator, and to produce the filter member at lower cost, 15 adopting a shorter filter unit as the filter member used in a longer tubular gas generator, and arranging plural shorter filter units in the device. SOLUTION: In order to cause filter units 3A in a filter member 3 to show enough performance such as slag collecting and others, it is preferable to insert an annular sealing material 16 between piled plural filter units 3A. A molded material made with heat resistant ceramic fiber and graphite sheet are preferably used for the sealing material 16. When the sealing material 16 is inserted between filter units 3A, mutual flow of high-temperature gas which flows from each gas inlet 8a through two filter units 3A is shielded by the sealing material 16, and each filter unit 3A is used effectively axially and the high-temperature gas is cooled down with collecting slag in it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas generator for an air bag mounted on an automobile, and more particularly to a long cylindrical gas generator used for a passenger air bag or the like.

[0002]

2. Description of the Related Art Conventionally, as a gas generator for a passenger airbag, a gas generator has to be disposed in a narrow space in an instrument panel of an automobile, generate a large amount of gas, and inflate the airbag greatly. In order to satisfy such factors as above, a long cylindrical shape is adopted.

[0003] This type of gas generator is, as shown in FIG.
It has a long cylindrical housing 50 in which a sealed space is formed by a long outer cylinder 51 and a lid member 52, and a length defining an annular space S between the housing 50 and the outer cylinder 51. A long inner cylinder 54 is housed, a long cylindrical filter 55 is housed in the annular space S, and a gas generating agent 53 is housed in the inner cylinder 54. An igniter 56 ignited by the collision detection of the collision sensor,
And a gas generating agent 53 that is ignited by the ignition and spreads the flame, and a gas generating agent 53 that is ignited by the firing agent 57 and generates a large amount of high-temperature gas. The filter member 55 used for the gas generator is provided with a gas generating agent 53.
And collects slag and the like in the high-temperature gas supplied from the large number of openings 54a of the inner cylinder 54 generated by the combustion of the inner cylinder 54, and cools the slag and the like. The airbag 51 is discharged into the passenger airbag through a large number of openings 51a and inflated. As described above, since the filter member 55 used for the gas generator is required to have sufficient heat resistance to withstand the high-temperature gas in addition to the ability to sufficiently collect the slag from the high-temperature gas. A flat woven wire mesh whose mesh is made fine by a wire (stainless steel or the like) is used alone, or the wire mesh and a sintered filter are wound together and the terminal portion is fixed by spot welding or the like. .

[0004]

However, the filter member used in the conventional gas generator has sufficient performance in collecting slag and the like from high-temperature gas and heat resistance, but has a fine mesh (mesh). Since the wire mesh is wound, the cost of processing the wire mesh increases, which increases the cost. In particular, in order to apply the filter member to a gas generator having a long cylindrical shape, the filter member itself also needs gas. The length becomes longer in proportion to the generator, and the cost tends to increase.
Therefore, reduction of the cost of the filter member has been one of the problems in the production of a gas generator accompanying the spread of airbags for passenger seats as well as for driver seats in recent years.

In order to reduce the production cost of the gas generator,
For example, as described in Japanese Patent Application Laid-Open No. 7-285412, the end of a cylindrical knitted metal mesh is repeatedly folded many times on the outer peripheral surface of the cylinder to form a cylindrical multiple-folded metal mesh. There is known a filter that compresses a filter of a desired length by compressing the filter in the length direction, but this filter is intended to be mainly applied to a gas generator of an airbag for a driver's seat. However, it cannot be used as a filter for a gas generator of a passenger airbag.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and provides an inexpensive filter structure suitable for a long cylindrical gas generator mainly used for a passenger airbag. The purpose of this is to reduce the cost of the gas generator.

[0007]

The gas generator of the present invention comprises:
A filter member is housed in a long annular space defined by an outer cylinder having a large number of gas discharge openings and an inner cylinder having a large number of gas inflow holes, and a gas generating agent is provided in the inner cylinder. This is a long cylindrical gas generator that is housed. Here, the filter member is composed of a plurality of filter units formed by compression-molding an aggregate of a wire mesh or a wire into a cylindrical shape, and each filter unit has a shaft in an annular space between the outer cylinder and the inner cylinder. It is laminated and inserted in the direction.

As described above, since the filter member is formed by laminating filter units that can be manufactured using inexpensive materials, a plurality of filter units are laminated even if the gas generator becomes long. It can be easily dealt with simply by doing so.

It is preferable that the openings of the inner and outer cylinders are positioned so that the position of the lamination boundary surface between the filter units stacked in the axial direction does not coincide with the position of the openings of the inner and outer cylinders. . As a result, the gas does not leak from the inner cylinder directly to the outside (airbag) through the lamination boundary surface, but can be surely passed through each filter member, thereby improving the use efficiency of the filter member. Becomes possible.

[0010] Further, a seal member for blocking the flow of the high-temperature and high-pressure gas between the filter units may be arranged on the lamination boundary surface of each filter unit. This allows
Since the flow of gas passing through each filter unit from the opening of the inner cylinder is blocked by the seal material, each filter unit is effectively used in the axial direction, and the slag contained in the gas is reliably captured. It can be cooled while gathering.

The filter unit is preferably formed by compressing a knitted wire mesh or an aggregate of crimp-formed wires into a cylindrical shape, thereby making it possible to manufacture the filter unit at low cost.

Further, the inner and outer cylinders are provided with a plurality of rows of openings, respectively, and a center line passing through the center of the opening of the outer cylinder and a center line passing through the center of the opening of the inner cylinder are orthogonal to each other. There is also a type in which each opening of the inner and outer cylinders is positioned. Thereby, gas can be supplied to each filter unit through the opening of the inner cylinder, can pass through the inside of the filter unit in the circumferential direction, and can be released to the outside through the opening of the outer cylinder, and effective use of the filter unit in the circumferential direction is achieved. Can do things.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. First, FIG.
FIG. 1 shows a cross-sectional view of a gas generator according to the present invention. The gas generator X has a long and cylindrical housing 1, a gas generating agent 2 housed in the housing 1, and a long cylindrical shape. The filter 3 and the ignition device 4 are configured as main parts. The housing 1 of the gas generator X is composed of an elongated, bottomed outer cylinder 5 having one end opened, and a cover member 6 covering the opening of the outer cylinder 5. The closed space is formed by abutting the annular rib 6a formed in the portion and the opening end of the outer cylinder 5 and performing friction welding. In the housing 1, a long inner cylinder 8 that partitions a long annular space S with the outer cylinder 5 is housed, and a thin plate cylinder that plays a role of moisture prevention and internal pressure adjustment in the annular space S. Burst plate 7 and long cylindrical filter member 3
Is stored. Further, a large number of gas generating agent pellets 2 are stored in the inner cylinder 8. Reference numeral 15 denotes a cushion member disposed at the bottom of the outer cylinder 5 for the gas generating agent 2, the inner cylinder 8 and the filter member 3.

A plurality of gas discharge holes 5a (opening) are formed in the outer peripheral surface of the outer cylinder 5 and communicate with the airbag (not shown). Filter member 3
A large number of gas inflow holes (openings) 8a communicating with the sides are formed. Each gas discharge hole 5a and each gas inflow hole 8a are
Each of the openings 5a, 8a is formed in a plurality of rows,
As shown in FIG. 2, are formed so that the center line a of the gas discharge hole row and the center line b of the gas inflow hole row are orthogonal to each other. That is, the gas discharge hole 5a and the gas inflow hole 8a
Are alternately formed on the outer cylinder 5 and the inner cylinder 8 while having a phase of 90 degrees in the circumferential direction of the housing 1.

In each row of the gas discharge holes 5a and the gas inflow holes 8a, the gas discharge holes 5a or the gas inflow holes 8a are formed in the axial direction of the housing 1 as shown in FIG. A perforated portion α and a non-porous portion β in which the opening is not formed
Are formed in each of the tubes 5 or 8 so as to appear alternately. Then, when the gas generating agent 2 is burned by the ignition device 4, the high-temperature gas generated by this burning is passed through the gas inlet holes 8a of the inner cylinder as shown in FIG.
And is passed through the inside of the filter member 3 in the circumferential direction and is discharged into the airbag from the gas discharge holes 5a of each outer cylinder.
Thereby, the filter member 3 can be effectively used over the entire circumference, and the slag or the like contained in the high-temperature gas can be reliably collected and cooled.

The cover 6 of the housing 1 is provided with an igniter 4 composed of a transfer agent 9 and an igniter 10 (electric detonator). The transfer agent 9 of the ignition device 4 is arranged so as to separate the gap h from the projection 6b of the lid member 6 inserted into the inner cylinder 8,
The gas generating agent 2 is separated from the gas generating agent 2 by a flanged cap member 11 fitted into the lid member 6. The flange portion 11a of the cap member 11 extends from the side of the lid member 6 of the inner cylinder 8 to the cushion material 12 that closes the filter member 3, and this tip 11b is formed at the time of butt welding of the outer cylinder 5 and the lid member 6. It is fixed in contact with the burr 5 b of the outer cylinder 5. As the cushion material 12, a molded product such as a silicon foam or a ceramic fiber is preferable. The protrusion 11 c of the cap member 11 has a through hole 1 for transmitting an ignition flame to the gas generating agent 2.
1d is formed. The igniter 10 of the igniter 4 is fitted into the lid member 6 and faces the igniting agent 9 in the convex portion 11c of the cap member 11 with a gap h. Then, the ignition device 4 ignites the igniter 10 by detecting the impact of a collision sensor (not shown), ignites the transfer agent 9, and causes the flame to be injected into the inner cylinder 8 from the through hole 11 d of the cap member 11. Thus, the gas generating agent 2 is burned to generate a high-temperature gas.

Next, the long cylindrical filter member 3 used in the gas generator X will be described. FIG. 4 shows an example of a filter unit used in the present invention. The filter unit 3A is formed by sintering a plurality of wire mesh layers 22a to 22c and joining ends of a sintered body 22 integrated therewith. After being bent into a cylindrical shape, the butted portion is joined and formed by welding, brazing, or the like. The filter member 3 is composed of a plurality (for example, two) of cylindrical filter units 3A. And these filter units 3A
Are inserted in the annular space S between the outer cylinder 5 and the inner cylinder 8 in a state of being stacked in the axial direction of the housing 1.

The length dimension L of each filter unit 3A is
The annular space S serving as a filter member arrangement portion of the gas generator
The length is set to one-half or one-third of the standard length, and a plurality of filter units 3A are arranged in the annular space S. Further, the gas inlet hole 8a of the inner cylinder 8 and the gas discharge hole 5a of the outer cylinder 5 are positioned so that the lamination boundary surface Z of the filter unit 3A is located at the non-porous portion β between the inner cylinder 8 and the outer cylinder 5. Is preferably performed. Accordingly, even when the filter member 3 is configured by stacking the plurality of filter units 3A, the high-temperature gas generated by the combustion of the gas generating agent 2 is discharged from the inner cylinder 8
From the gas inflow hole 8a of the outer cylinder 5 through the gas discharge hole 5a of the outer cylinder 5 through the lamination boundary surface Z, and can be passed through each filter unit 3A without fail. The unit 3A can cool the slag or the like of the high-temperature gas while surely collecting the slag, and discharge the clean gas to the airbag.

As shown in FIG. 3, a plurality of (two) stacked filter units 3A are required to fully exhibit the performance of collecting slag and the like of each filter unit 3A of the filter member 3. It is preferable to insert an annular sealing material 16 in the (lamination boundary surface Z). As the sealing material 16, a molded article of heat-resistant ceramic fiber or a graphite sheet is preferable. When the seal material 16 is inserted between the filter units 3A, the flow of the high-temperature gas passing through the two filter units 3A from each gas inlet hole 8a is interrupted by the seal material 16.
Each filter unit 3A is effectively used in the axial direction, and can cool while reliably collecting slag and the like contained in the high-temperature gas.

First, as shown in FIG. 5A, the filter unit 3A constituting the filter member 3 has the wire mesh layers 22a to 22a.
22c is laminated into three layers (the number of layers is not limited) to form a sheet-like wire net. Each of the wire mesh layers 22a to 22c is made of a sheet-like wire mesh using a plurality of materials such as stainless steel. The wire mesh is made of a coarse mesh plain weave or a knitted fabric (see FIG. 5B). Can be After the wire mesh layers 22a to 22c are formed into sheet-like wire meshes, the laminated wire meshes are compressed (pressed) in a softened state while being heated to about 1000 ° C. in a sintering furnace, so that the wires are mainly entangled and integrated. To form a sintered body 22 having a mechanical bonding force. This integrated sheet-like sintered body 2
4 is cut into a predetermined length and width, and as shown in FIG. 4, both ends are formed into a cylindrical shape, and the butted portion is joined 23 by welding, brazing, or the like, thereby forming an annular shape between the inner and outer cylinders. A desired filter unit 3A having an outer diameter and a length L that can be inserted into the space S is formed. The filter unit 3A may be formed by cutting the sheet-shaped sintered body 22 into a cylindrical shape first and then cutting the sheet-shaped sintered body 22 into a predetermined width dimension H. As described above, since the sheet-shaped sintered body 22 is given a fixed shape by integration, it can be cut with high accuracy, and can be formed into a cylindrical shape with both ends abutted. Accordingly, the dimensional accuracy of the obtained filter unit 3A is improved, the manufacturing process is simplified, and the filter unit can be manufactured at low cost.

The structure of the filter unit 3A is different from that shown in FIG.
(A). This filter unit 3A differs from the filter unit of FIG. 4 in the method of joining the cylindrical ends. That is, in the filter unit of FIG. 4, the sheet-shaped sintered body 22 is formed into a cylindrical shape and the ends thereof are welded and joined, but the one shown in FIG. As shown in FIG. 3, a sintered body 22 having a three-layer structure of an outer layer 22a, an intermediate layer 22b, and an inner layer 22c is shown.
Is formed into a cylindrical shape, and its ends 34 and 35 are overlapped. Then, the overlapped portion is compressed by press working so that the thickness t1 becomes the same as the thickness t2 of the other portions. No, then both ends are joined by spot welding 33. According to this method, a butt welding step is not required, and compression and spot welding can be performed in one step, so that productivity is improved, mass production is facilitated, and the cost is reduced. The configuration of each layer of the filter unit 3A in this case is the same as that in FIG.

The structure and forming method of the filter unit 3A are not limited to those described above. For example, a cylindrical knitted wire mesh (shown in FIG. 5B)
Is folded over the outer peripheral surface of the cylinder a number of times to form a cylindrical multi-fold formed wire mesh, and the formed wire mesh is compressed in the longitudinal direction to compression-mold the filter unit 3A having a desired length L. Alternatively, a knitted wire mesh wound up into a cylindrical shape may be simply formed by compression molding, and further, as shown in FIG. May be rolled up into a cylindrical shape and compressed to form a dense cylindrical body. As described above, as the filter unit 3A used in the present invention, any filter unit can be used as long as it is normally used as a filter member for a gas generator. From the viewpoint of maintaining the elasticity, a material having some elastic force in the axial direction, such as a material obtained by compression molding into a cylindrical body using a knitted wire mesh or a material obtained by molding a crimped wire into a cylindrical shape and compressing it. Is more preferred.

As described above, according to the gas generator of the present embodiment, the filter member 3 is formed by stacking the filter units 3A which can be manufactured at a low cost.
Even if the gas generator X is long, it can be easily and inexpensively handled only by stacking the plurality of filter units 3A.

The openings 5a, 8a of the cylinders 5, 8 are formed so that the lamination boundary surface Z where the filter units 3A are in contact with each other is located at the non-porous portion β of the cylinders 5, 8. When the openings 5a and 8a are formed in the cylinders 5 and 8 such that the center lines a and b of the openings are orthogonal to each other, the high-temperature gas generated by the combustion of the gas generating agent 2 causes the filter unit 3A to emit hot gas. The gas is always supplied to each filter unit 3A from the gas inlet hole 8a of the inner cylinder 8 without being directly discharged to the airbag from the lamination boundary surface Z, and the gas is discharged from the outer cylinder 5 after passing through the circumferential direction of each filter unit 3A. The air is released into the airbag through the hole 5a. At this time, the high-temperature gas is uniformly dispersed in the axial direction from each of the gas inlet holes 8a of the inner cylinder 8, and the filter units 3
A, and flows in the axial direction and the circumferential direction of the filter unit 3A.
It is used over substantially the entire length and the entire circumference, so that the efficiency of the filter member is improved, and slag contained in the high-temperature gas can be efficiently collected and the gas can be cooled. Further, when the sealing material 16 is inserted into the lamination boundary surface Z between the laminated filter units 3A, the supplied high-temperature gas is shut off so as not to flow between the filter units 3A. It can be expected that the utilization of the filter unit 3A will be improved.

Although the gas generator in the present embodiment has been described with reference to an airbag device for a passenger seat of an automobile, the present invention is not limited to this, and may be any gas generator having a cylindrical shape. For example, application to a long cylindrical gas generator for a side collision airbag device may be considered.

[0026]

As described above, according to the gas generator of the present invention, a short filter unit 3A is adopted as the filter member 3 used for the long cylindrical gas generator, and a plurality of the filter units 3A are inserted. Since the filter member is arranged, it is not necessary to design and manufacture the filter member each time according to the size of the gas generator, and as a result, the filter member can be manufactured inexpensively. In addition, since the filter member is configured only by laminating inexpensively manufactured filter units, even if the gas generator becomes long, it can be easily handled simply by changing the number of layers of multiple filter units. And contributes to the cost reduction of the gas generator itself.

Further, since the openings of the cylinders are arranged so as to be shifted so that the lamination boundary surface Z of each filter unit does not coincide with the opening of each cylinder, a plurality of filter units are laminated and the filter is formed. In this configuration, the gas does not pass from the inner cylinder directly through the lamination boundary surface to the outside (into the airbag), and can be passed through each filter section without fail. As the slag collection efficiency is improved, the gas cooling efficiency is also improved, and it becomes easy to discharge the clean gas at an appropriate temperature to the airbag.

Further, by disposing a sealing material on the lamination boundary surface Z of each filter member unit, the flow of gas passing through each filter unit from the opening of the inner cylinder is interrupted by the sealing material. Therefore, each filter unit can be effectively used in the entire axial and circumferential directions, and it is expected that the efficiency of collecting slag contained in the gas is further improved.

If a knitted wire mesh or a crimp-formed wire assembly obtained by compression molding is used as the filter unit, it has an axial elastic force, so that not only can it be manufactured at low cost, There is an effect that the insertion becomes easy and the position is stably held even after the insertion.
Further, there is an effect that the leakage of the slag from the filter end surface is suppressed.

Further, by arranging the row of apertures of the inner cylinder and the row of apertures of the outer cylinder at right angles to each other, the gas flowing into the filter member from the aperture of the inner cylinder is reduced by the thickness of the filter member. Rather than direct current in the direction, it flows in the axial direction and circumferential direction to reach the opening of the outer cylinder, so that the filter member
It can be used more effectively over the entire length, and the slag collection efficiency and gas cooling efficiency can be further improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a long tubular gas generator according to the present invention.

FIG. 2 is an enlarged cross-sectional view taken along line AA of FIG.

FIG. 3 is an enlarged view of a main part of FIG. 1;

FIG. 4 is a perspective view showing an example of a filter unit used in the present invention.

5A is a partial cross-sectional view of the filter unit in FIG. 4, and FIG. 5B is a diagram illustrating an example of a wire mesh used in the filter unit.

FIG. 6A is a perspective view showing another example of the filter unit used in the present invention, and FIG. 6B is a conceptual view showing a part of the manufacturing process.

FIG. 7 is a conceptual drawing showing an example of a wire forming a filter unit used in the present invention.

FIG. 8 is a cross-sectional view showing a conventional long cylindrical gas generator.

[Explanation of symbols]

 Reference Signs List 3 filter member 3A filter unit 5 outer cylinder 5a gas discharge hole (open hole) 8 inner cylinder 8a gas inflow hole (open hole) 16 sealing material a, b center line S annular space Z laminated boundary surface

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Kenichi Nagahashi 3903-39, Tomicho, Himeji-shi, Hyogo Prefecture Nippon Kayaku Co., Ltd. Himeji Plant Sensor Technology Co., Ltd. Himeji Technical Center (72) Inventor Kikuchi Dai Hyogo 3903-39, Tomicho, Himeji-shi, Japan Nippon Kayaku Co., Ltd.Sensor Technology in Himeji Factory, Himeji Technical Center Co., Ltd. (72) Inventor Yoshiyuki Kishino 3903-39, Tomicho, Himeji-shi, Hyogo Nippon Kayaku Himeji Inside Sensor Technology Co., Ltd. Himeji Technical Center Co., Ltd. (72) Inventor Seigo Taguchi 3903-39 Abundant Town, Himeji City, Hyogo Prefecture Nippon Kayaku Co., Ltd. Himeji Technical Center Co., Ltd.

Claims (5)

[Claims] An elongated annular space defined by an outer cylinder (5) having a large number of gas discharge openings (5a) and an inner cylinder (8) having a large number of gas flow openings (8a). (S) containing a filter member (3) in the inner tube (8) and a gas generating agent (2) in the inner tube (8); ) Is composed of a plurality of filter units (3A) formed by compression-molding an aggregate of a wire mesh or a wire rod, and each of the filter units (3A) includes the outer cylinder (5) and the inner cylinder (8). A gas generator characterized by being axially stacked and interposed in an annular space (S) between them. 2. The position of the laminating boundary (Z) between the filter units (3A) laminated in the axial direction and the positions of the apertures (5a, 8a) of the inner and outer cylinders do not match.
2. The gas generator according to claim 1, wherein the openings (5a, 8a) of the inner and outer cylinders are positioned. 3. A sealing material (16) interposed between the filter units (3A) to block the flow of gas between the filter units (3A) is interposed at the lamination boundary surface (Z) of the filter units (3A). Gas generator according to 1 or 2 4. The gas according to claim 1, wherein each of the filter units (3A) is formed by compression-molding a knitted wire mesh or an aggregate of crimp-formed wires into a cylindrical shape. Generator 5. Openings (5a, 8) of said inner and outer cylinders (5, 8).
a) are arranged in a plurality of rows, respectively, a center line (a) passing through the center of the row of apertures of the outer cylinder (5) and a center line (a) passing through the center of the row of apertures of the inner cylinder (8). The gas generator according to any one of claims 1 to 4, wherein each opening (5a, 8a) of the inner and outer cylinders is positioned such that b) is orthogonal to each other.