JPH09136603A - Airbag inflator - Google Patents

Abstract

(57) Abstract: In an inflator for deploying and inflating an airbag, a filter assembly can be reliably fixed to a housing without complicating the manufacturing process. SOLUTION: In an airbag inflator in which filter means for filtering / cooling combustion gas is fixed to a cylindrical housing 1, as a whole, a large number of fumaroles 4 are distributed in a band shape along the axial direction. The fumarole opening is provided on the peripheral wall of the housing, and the filter means is composed of a thin plate-shaped filter material 32 and a frame member 33 that holds the outer peripheral portion of the filter material to cover the fumarole opening. Thus, the filter means is fixed to the housing with its frame member. In particular, it is assumed that the housing body is provided with the position defining means for the outer edge of the frame member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inflator for deploying and inflating an airbag.

[0002]

2. Description of the Related Art In an air bag device provided in a vehicle compartment to protect an occupant's body from a shock at the time of a vehicle collision, in order to rapidly expand and inflate a folded and stored bag-shaped air bag, there is a deflagration. An inflator in which a high-pressure gas is obtained by burning a volatile gas generating agent is often used (see Japanese Patent Application Laid-Open No. 5-50894).

In such an inflator, in order to prevent residual solid matter mixed in the combustion gas generated by the combustion of the gas generating agent from scattering and the air bag body from being damaged by the high temperature combustion gas, The combustion gas supplied into the airbag body is filtered and cooled by passing through a filter.

By the way, as an inflator in which a housing for a gas generating agent is formed in a tubular shape, a filter assembly made of wire mesh is wrapped in a tubular shape and wound around it, and the end portions thereof are adhesively fixed by welding or the like to be integrated. Is housed in the housing in a state of being in close contact with the inner peripheral surface of the housing,
It is known that the combustion gas generated by the combustion of the gas generating agent loaded in the inner space of the filter assembly is ejected through the filter material from a large number of fumaroles formed on the peripheral wall of the housing. There is.

[0005]

However, in order to insert such a filter assembly through the opening at the end portion of the housing and bring it into close contact with the inner peripheral surface of the housing, the outer diameter of the filter assembly and the inner diameter of the housing are mutually interrelated. It is necessary to strictly control the dimensional accuracy. However, since it is difficult to improve the contour accuracy due to a structural reason such as winding the wire mesh, it is necessary to apply an external force to correct the shape of the filter assembly when the filter assembly is inserted into the housing. Therefore, the manufacturing process tends to be complicated.

Further, in order to securely fix the filter assembly to the housing, the filter material is deformed when sandwiched by the lids at both ends of the housing, so that the filter material is brought into close contact with the inner surface of the housing. However, according to this method, it is difficult to designally estimate the certainty of fixation due to changes over time.

[0007] The present invention has been devised to solve such disadvantages of the prior art, and its main objects are as follows.
It is an object of the present invention to provide an inflator for an airbag configured so that the filter assembly can be reliably fixed to the housing without complicating the manufacturing process.

[0008]

According to the present invention, such an object is, as a whole, an airbag inflator in which a filter means for filtering and cooling combustion gas is fixed to a cylindrical housing. While providing a fumarole opening portion in which a large number of fumaroles are distributed in a band shape along the axial direction on the peripheral wall of the housing, the filter means is provided.
A thin plate-shaped filter material and a frame member that holds an outer peripheral portion of the filter material, and the filter means is fixed to the housing by the frame member so as to cover the opening for the fumaroles. It is achieved by providing an airbag inflator.

Particularly, it is preferable that the housing body is provided with a position defining means for the outer edge of the frame member.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of the present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings.

1 and 2 show a basic embodiment of an airbag inflator constructed according to the present invention. This inflator includes a cylindrical housing body 1 loaded with a gas generating agent, and the housing body 1
Cylindrical ignition tube 2 having substantially the same length as the axial dimension of
And a bottom plate 3 that closes one opening of the housing body 1. The ignition tube 2 is fixed to the inner peripheral surface of the housing body 1 by brazing or welding along the axial direction, and the bottom plate 3 is similarly brazed or welded to both end surfaces of the housing body 1 and the ignition tube 2. Is stuck by.

The housing body 1 is provided with a rectangular window hole 27 which is long in the axial direction, and a perforated plate 11 having a large number of fumaroles 4 is formed so as to close the window hole 27. It is fixed to the inner surface of the part by brazing or welding. Then, in the window hole 27 closed by the perforated plate 11, the filter material 3 formed by superposing a plurality of kinds of wire nets
2 and the housing body 1 holding the filter material 32
The filter assembly 13 including the frame member 33 fixed to the outer peripheral surface of the is superposed.

The ignition tube 2 is loaded into a combustion chamber defined between the inner peripheral surface of the housing body 1 and the outer peripheral surface of the ignition tube 2 in response to the operation of an igniter (not shown) connected thereto. A plurality of small holes 6 for emitting an ignition flash for igniting the gas generating agent are provided.

The other opening of the housing body 1 is filled with a gas generating agent and then closed by a cover plate (not shown). While this bottom plate 3 is fixed to the bottom plate 3 by brazing or the like,
It is fixed to the housing body 1 with screw means.

The frame member 33 of the filter assembly 13 includes a frame portion 33a having a U-shaped cross section for holding the outer peripheral portion of the filter material 7, and a crosspiece 33b provided on the outer surface side of the filter material 7 in the circumferential direction. And is curved so as to be in close contact with the outer peripheral surface of the housing body 1. The outer peripheral edge of the frame member 33 and the opening edge of the window hole 27 are joined to each other by brazing or welding.

FIG. 3 shows a modified embodiment of the filter fixing structure according to the present invention. In this filter fixing structure, the rib 5 that defines the position of the outer peripheral edge portion in the longitudinal direction of the frame member 33 of the filter assembly 13 is provided with the longitudinal length of the window hole 27 that is opened in the housing body 1 to dispose the perforated plate 11. One pair extends along the opening edge in the direction. This simplifies the positioning operation of the filter assembly 13 with respect to the housing body 1. It should be noted that the same effect can be obtained by providing a recessed step portion for receiving the outer peripheral edge portion of the filter assembly 13 at the opening edge portion of the window hole 27.

Further, as shown in FIG. 4, the rib 5 is provided so as to grip the outer peripheral edge of the frame member 33 of the filter assembly 13.
Alternatively, a claw piece extending inward may be formed. By doing so, it is possible to restrain the springback that occurs when brazing is performed in the heating furnace by using the brazing sheet in which the brazing material is clad in advance. In this case, the filter assembly 13 is axially inserted from the opening end side of the housing body 1 having an equal cross section. Further, the claw pieces are formed so as to extend straight in the radial direction, and the filter assembly 1
After positioning 3, the claw pieces may be bent inward to fix the filter assembly 13 and the housing body 1.

FIG. 5 shows a second modified embodiment of the filter fixing structure according to the present invention. In this filter fixing structure, a pedestal portion 8 having a flat top surface 8a is provided on the outer peripheral surface of the cylindrical housing body 1 in a protruding manner.
The flat plate-shaped filter assembly 13 is fixed to the opening edge of the window hole 27 penetrating from a. The edge of the top surface 8a projects slightly and positions the filter assembly 13.

In each of the above embodiments, the filter assembly 13 is arranged outside the housing body 1, but it may be arranged inside. Also,
As shown in FIG. 6, the window holes 27 provided with the perforated plate 11 are placed at symmetrical positions so that the combustion gas is dispersed and ejected in two directions.
It is also possible to provide a pair, and in this case, a pair of filter assemblies 13 is provided corresponding to these.

Although the housing body 1 has a perfect circular cross section, the present invention is not limited to this.
The shape may be an elliptical shape, an oval shape, a rectangular shape, a triangular shape, or the like, and an optimum cross-sectional shape can be appropriately adopted depending on the portion where the vehicle interior is arranged. Then, the window hole 2 is formed on the flat peripheral wall formed by forming the housing body 1 in an oval or rectangular shape.
If 7 is opened, the filter assembly 13 can be formed into a flat plate shape together with the perforated plate 11.

Further, although the fumaroles 4 are formed in the porous plate 11 which is different from the housing body 1, the same can be applied when the fumaroles are directly formed in the peripheral wall of the housing body 1. Alternatively, the frame member 33 of the filter assembly 13 and the perforated plate 11 may be directly joined to each other so that the perforated plate 11 serves as a support for the filter assembly 13, and then the perforated plate 11 is disposed in the housing body 1.

[0022]

FIG. 7 to FIG. 9 show a specific example of an airbag inflator to which the present invention is applied. This inflator comprises a housing body 1 formed into an elliptic cylindrical shape by extrusion molding of an aluminum alloy material, a perforated plate 11 accommodated in the housing body 1 side by side in the minor axis direction, a partition 9, and an ignition tube. And the leg assembly 12, the filter assembly 13 fixed to the outer surface of the housing body 1, the bottom plate 3 fixed to one opening end surface of the housing body 1, and the other opening end surface of the housing body 1 with screws. And a cover plate 14 that

The partition body 9 has a large body 2 inside the housing body 1.
It is for partitioning into one combustion chamber and is formed separately from the housing body 1. The ignition tube and leg assembly 12 is formed by integrally forming the ignition tube 2 and the leg portion 7 that supports the ignition tube 2. The partition 9 and the ignition tube and leg assembly 12 are made by subjecting a plate material made of an aluminum alloy to predetermined hole processing and then bending the plate material into a predetermined shape by roll forming or the like.

The filter assembly 13 is for preventing the scattering of the residual solid matter generated by the combustion of the gas generating agent and the exposure of the flame. The filter assembly 13 is a two-piece axially extending outer peripheral surface of the housing body 1. The ribs 15 are fixed in a fitted state. In addition, the filter assembly 13
A rib 16 having the same shape as these ribs 15 is formed in the center of the surface opposite to the surface on which the ribs are provided. A screw hole 18 into which a screw 17 for fixing the lid plate 14 is screwed is formed at one end of each of the three ribs 15 and 16.

The cover plate 14 is formed in a shape substantially identical to the cross-sectional contour of the housing body 1, and has a center through which a stud bolt 19 inserted into an end portion of the ignition tube portion of the ignition tube and leg assembly 12 is inserted. A hole 20 is formed in the center of the hole, and three ear pieces 22 having screw insertion holes 21 are provided at positions corresponding to the ribs 15 and 16 of the housing body 1. A gasket 23 having the same shape as the lid 14 is sandwiched between the lid 14 and the housing body 1.

Stud bolts 19 protruding from the cover plate 14
At the tip of the
This stud bolt 1
The inflator can be attached to the inside of the airbag (not shown) through the boss 9 and the boss 26 provided on the outer surface of the bottom plate 3. The stud bolt 19 and the hole 20 of the lid plate 14 through which the stud bolt 19 is inserted are not necessary depending on the mounting manner in the airbag.

As shown in FIGS. 8 and 9, the housing body 1 is provided with two rectangular window holes 27, and a large number of fumaroles 4 are provided so as to close the window holes 27. The perforated plate 11 is fixed to the inner peripheral surface of the housing body 1.

The perforated plate 11 is formed by punching a plate made of an aluminum alloy with a press or the like, and then bending the plate to a predetermined curvature by press forming so as to be in close contact with the inner peripheral surface of the housing body 1. . Circular fumaroles 4a are axially arranged in the circumferential center of the perforated plate 11, and oblong fumaroles 4b elongated in the circumferential direction are axially arranged on both sides of the fumarole 4a. It is set up. The perforated plate 11 is positioned by a pair of protrusions 28 formed on the inner peripheral surface of the housing body 1 in the axial direction.

The partition body 9 is composed of an arc-shaped plate portion 9a that is in close contact with the inner surface of the perforated plate 11 and side plate portions 9b having a hook-shaped cross section that hangs from the left and right ends thereof. In the arc-shaped plate portion 9a, circular holes 29 of substantially the same size as the circular fumaroles 4a of the perforated plate 11 are axially arranged in a row. In the left and right side plate portions 9b, communication holes 10 that open toward both sides of the ignition tube portion are arranged in a line in the axial direction.

The ignition tube and leg assembly 12 is formed by integrally forming an ignition tube 2 bent in a circular tube shape and a leg 7 supporting the ignition tube 2. In this ignition tube 2, small holes 6 opened between the left and right side plate portions 9b of the partition body 9 are arranged in a line in the axial direction, and an igniter connected to this ignition tube 2 is connected to the collision detection sensor. When actuated in response to an electrical or mechanical signal, the ignition flash spouts simultaneously from the small holes 6 and ignites the gas generating agent around it.

The leg portion 7 extends outward in the radial direction from the seam of the ignition tube 2 bent in a circular tube shape, and the flanges 30 project from opposite sides at the free ends thereof. There is. The flange 30 is fitted between a pair of protrusions 31 formed on the inner surface of the housing body 1 in the axial direction, and the ignition tube and the leg assembly 12 are positioned.

The filter assembly 13 is composed of a filter material 32 formed by superimposing a plurality of kinds of wire mesh and a frame material 33 for holding the mesh, and is curved so as to be in close contact with the outer peripheral surface of the housing body 1. ing. The frame material 33 is joined to the filter material 32 by bending a plate material made of aluminum alloy by a press or the like so as to hold the outer peripheral portion of the filter material 32 and then bending the hole material. The frame member 33 has four square holes 34 corresponding to the circular fumaroles 4a of the perforated plate 11 and four oblong fumes 4b.
There are 12 rows in total.

The bottom plate 3 has the same shape as the lid plate 14, and a boss 26 is projected on the outer surface thereof. And this boss 26
An igniter (not shown) is fitted in the center hole of the igniter. It is opened in.

The porous plate 11, the partition 9, the ignition tube and leg assembly 12, and the frame member 3 of the filter assembly 3
A brazing sheet in which a brazing material is pre-clad on both sides or one side is adopted as a plate material made of an aluminum alloy which is a material of each of the members of 3 and the bottom plate 3. Therefore, the perforated plate 11, the partition body 9, and the ignition tube and leg assembly 12 formed in a predetermined shape are attached to the housing body 1.
And insert the stud bolt 19 into the ignition tube 2
When the filter assembly 13 and the bottom plate 3 are positioned and then placed in a heating furnace, the brazing material is melted and the members are brazed together to be integrated. Then, an igniter is attached to the boss 26 of the bottom plate 3, a gas generating agent is loaded into the combustion chamber 8, and the lid plate 14 and the gasket 23 are screwed to complete the inflator. If necessary, an ignition agent is loaded inside the ignition tube 2.

【The invention's effect】

As described above, according to the present invention, when the fumarole opening portion in which a large number of fumarole holes are distributed in the form of a strip along the axial direction is provided on the peripheral wall of the housing body, the fumarole opening portion is selected. A filter is arranged in a part in the circumferential direction so as to cover the area. Therefore, the filter itself becomes an open cross-section member and can be easily formed into a desired shape by press molding or the like. For example, if the housing body is cylindrical, the filter may be formed in an arc shape in accordance with the curvature of the opening of the fumarole of the housing body. Therefore, since the quality control is facilitated and the manufacturing process is simplified, there is an extremely remarkable effect in reducing the manufacturing cost. Moreover,
Since the filter material is securely fixed to the housing body by brazing or welding while being held by the frame material, the filter material does not rattle due to loosening due to aging.

Further, since the filter is arranged in a part in the circumferential direction so as to selectively cover the opening of the fumaroles in this manner,
Compared with the conventional product in which the filter material has to be arranged over the entire circumference, there is an advantage that the weight of the inflator can be reduced.

Particularly, if the housing body is provided with a position defining means such as a rib for defining the position of the outer edge portion of the frame member, the positioning operation of the filter means with respect to the housing body can be simplified. By extending the position defining means in the axial direction, the position defining means can be integrally formed with the housing main body by extrusion molding of a light alloy material, and an increase in manufacturing cost can be suppressed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a basic configuration of an airbag inflator constructed according to the present invention.

FIG. 2 is a cross-sectional view showing the inflator shown in FIG. 1 taken along a plane perpendicular to the axis.

FIG. 3 is a first inflator constructed according to the present invention.
Sectional drawing similar to FIG. 2 which shows the modified embodiment of this.

4 is a sectional view similar to FIG. 2, showing a modified embodiment in which the inflator shown in FIG. 3 is partially modified.

FIG. 5 is a second inflator constructed according to the present invention.
Sectional drawing similar to FIG. 2 which shows the modified embodiment of this.

FIG. 6 is a cross-sectional view similar to FIG. 2, showing an alternative embodiment with a pair of filter assemblies.

FIG. 7 is a perspective view showing an inflator to which the present invention is applied.

8 is an exploded perspective view of the inflator shown in FIG.

9 is a cross-sectional view of the inflator shown in FIG.

[Explanation of symbols]

 1 Housing Main Body 2 Ignition Tube 3 Bottom Plate 4 Fume Hole 5 Rib 6 Small Hole 7 Legs 8 Stands 9 Partitions 10 Communication Holes 11 Perforated Plates 12 Ignition Tube and Leg Assembly 13 Filter Assembly 14 Lid Plate 15 Rib (2 Articles) ) 16 ribs (1 row) 17 screw 18 screw hole 19 stud bolt 20 center hole 21 screw hole 22 ear piece 23 gasket 24 seat nut 25 lock nut 26 boss 27 window hole 28 ridge 29 circular hole 30 flange 31 ridge 32 Filter material 33 Frame material 34 Square hole 35 Circular hole

Claims (2)

[Claims] 1. An inflator for an air bag, wherein a filter means for filtering and cooling combustion gas is fixed to a cylindrical housing, and a large number of fumaroles are distributed in a band shape along the axial direction as a whole. The fumarole opening is provided on the peripheral wall of the housing, and the filter means is composed of a thin plate-shaped filter material and a frame member that holds the outer peripheral portion of the filter material. An inflator for an air bag, wherein the filter means is fixed to the housing with its frame member so as to cover the. 2. The inflator for an airbag according to claim 1, wherein the housing body is provided with a position defining means for an outer edge portion of the frame member.