JPH09136601A - Inflator for airbag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute an inflator for airbag so as to obtain the satisfactory inflation characteristics of the airbag by optimizing the combustion speed of a gas generating agent between a plurality of combustion chambers partitioned by a partition wall. SOLUTION: This inflator, whose housing 1 inside is partitioned into a plurality of combustion chambers 6a-6c, jets combustion gas into an air bag from a jetting hole 3 formed at the housing when a gas generating agent in the first combustion chamber 6a is ignited, and also ignites the gas generating agents in other combustion chambers 6b, 6c by means of the flames of the gas generating agents in the first combustion chamber to jet its combustion gas into the airbag from another jetting hole. When a straight line passing through the center of the first combustion chamber and the center of a flame throwing hole 9 is taken as y-axis and a straight line orthogonal to y-axis and passing through the center of the first combustion chamber is taken as x-axis, a communicating hole 10 for throwing flames from the first combustion chamber into another combustion chamber is provided at the third quadrant and the fourth quadrant with regard to the center of the first combustion chamber.

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 air bag, and more particularly to an inflator for an air bag having a plurality of combustion chambers.

[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 collision at the time of a vehicle collision, a bag-shaped air bag folded and stored is rapidly expanded and inflated. An inflator in which a high-pressure gas is obtained by burning an explosive gas generating agent is often used (see Japanese Patent Laid-Open No. 5-319199, etc.).

In such an inflator, since the heat energy taken up by the housing loaded with the gas generating agent and the airbag itself in the initial stage of combustion is considerably large, when the combustion speed of the gas generating agent is made constant, the impact is generated. To obtain sufficient expansion in the part that contributes to absorption, an extra gas generating agent is required accordingly. Therefore, it is difficult to reduce the size and weight of the device.

In order to reduce such heat loss and increase the pressure efficiency of the generated gas, two combustion chambers are provided by partitioning the inside of the housing with partition walls, and the gas generating agent in the first combustion chamber is ignited first. This gas is used to initially deploy the airbag vertically and horizontally and to preheat it, and to rupture the case housing the airbag, ignite the gas generating agent in the second combustion chamber with a slight delay, and then ignite the airbag. There is known an inflator configured to give an inflating force to an occupant.

[0005]

By the way, as described above, two combustion chambers are provided in the housing, and the flame of the gas generating agent in the first combustion chamber is guided to ignite the gas generating agent in the second combustion chamber. In such a case, since the expansion characteristics of the airbag are influenced by the cooperation of combustion between the first and second combustion chambers, the position of the communication hole for flame radiation becomes a problem.

In view of the above problems of the prior art, the present invention optimizes the combustion speed of the gas generating agent between a plurality of combustion chambers partitioned by partition walls, and obtains a satisfactory airbag inflation characteristic. The present invention has been devised for the purpose of forming an airbag inflator.

[0007]

In order to achieve such an object, in the present invention, the inside of the housing is divided into a plurality of combustion chambers, and the gas generating agent in the first combustion chamber is ignited by an igniter. Then, the combustion gas of this is ejected from the fumaroles provided in the housing into the air bag, while the flame of the gas generant in the first combustion chamber also ignites the gas generants in other combustion chambers. In an inflator for an air bag in which the combustion gas of No. 1 is also ejected from another fumarole into the air bag, a straight line passing through the center of the first combustion chamber and the center of the ignition flame radiating hole is defined as the y-axis, When a straight line orthogonal to the y-axis and passing through the center of the first combustion chamber is taken as the x-axis, the first combustion chamber to the other combustion chamber is located in the third quadrant and the fourth quadrant with respect to the center of the first combustion chamber. A communication hole for flame radiation of is to be provided.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of an airbag inflator according to the present invention. This inflator prevents the housing body 1 formed into an elliptic cylinder shape by extrusion molding of an aluminum alloy material to be loaded with a gas generating agent, and scattering of residual solid matter generated by combustion of the gas generating agent and exposure of flame. Therefore, a filter assembly 2 provided on the outer surface of the housing main body 1 in the minor axis direction and a large number of fumaroles 3 through which combustion gas is ejected are formed. A plurality of perforated plates 5 housed in the housing main body 1 so as to close the holes 4 and a plurality of insides of the housing main body 1 (in this embodiment, 3
No. 7), a partition 7 having a substantially U-shape, which is arranged so as to be in contact with both the inner surface of the perforated plate 5 and the inner surface of the peripheral wall of the housing body 1 facing the inner surface of the perforated plate 5 so as to be partitioned into
And a cylindrical ignition tube 8 that is inscribed in the bottom of the partition 7 to load the ignition agent.

The ignition tube 8 is divided between the inner peripheral surface of the housing body 1, the opposing inner surface of the partition 7 and the outer peripheral surface of the ignition tube 8 in response to the operation of an igniter (not shown) connected thereto. A plurality of small holes 9 for emitting an ignition flash for igniting the gas generating agent loaded in the formed first combustion chamber 6a are formed.

The partition body 7 is adjacent to the connecting portion with the ignition tube 8 and on both sides thereof, a communication hole for communicating between the first combustion chamber 6a and the second and third combustion chambers 6b and 6c. 10 are formed respectively. These communication holes 10 are formed in the first combustion chamber 6a.
When the straight line passing through the center O of the first combustion chamber 6 and the center of the ignition flash radiation small hole 9 is the y-axis, and the straight line passing through the center O of the first combustion chamber 6a orthogonal thereto is the x-axis, the center O of the first combustion chamber is To the third quadrant, i.e. inside x-O-y ', and the fourth quadrant,
That is, they are respectively provided on the inner side of y'-O-x '. By providing the communication hole 10 at such a position, the flame of the first combustion chamber 6a is changed to the second and third combustion chambers 6b.
6c, and the gas generation efficiency of the second and third combustion chambers 6b and 6c is improved.

The frame 2a of the filter assembly 2 described above,
The perforated plate 5, the partition body 7, and the ignition tube 8 are formed by a brazing sheet in which the surface of an aluminum base material is coated with a brazing material in advance. Therefore, after inserting the perforated plate 5, the partition 7 and the ignition tube 8 into the housing main body 1 so that each part is temporarily fixed, and the filter assembly 2 is positioned on the outer peripheral surface of the housing main body 1. When placed in a heating furnace, the brazing material on the surface is melted and the respective parts are brazed together and integrated.

[0013]

2 and 3 show a specific embodiment of an airbag inflator to which the present invention is applied. The inflator includes a housing body 1 formed in an elliptic cylinder shape by extrusion molding of an aluminum alloy material, a filter assembly 2 fixed to an outer surface of the housing body 1,
An ignition tube integrally formed with a perforated plate 5, a partition 7, an ignition tube 8 and a leg portion 13 for supporting the same in the center of the housing body 1, which are accommodated inside the housing body 1 side by side in the minor axis direction. / Leg assembly 14, a bottom plate 15 fixed to one opening end surface of the housing body 1, and a lid plate 16 screwed to the other opening end surface of the housing body 1.

The housing body 1 is provided with two rectangular window holes 4 aligned in the axial direction, and a perforated plate 5 is fixed to the inner peripheral surface of the housing body 1 so as to close the window holes 4. It is supposed to be done. The perforated plate 5 is formed by punching a plate material 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. The perforated plate 5 has a circular fumarole 3 at the center in the circumferential direction.
A are arranged in the axial direction, and elliptical fumes 3b elongated in the circumferential direction are arranged in the axial direction on both sides of the fumarole 3a. The perforated plate 5 is positioned by a pair of projections 17 formed on the inner peripheral surface of the housing body 1 in the axial direction.

The filter assembly 2 is composed of a filter material 2b formed by superposing a plurality of kinds of wire mesh and a frame body 2a for holding the same, and is curved so as to be in close contact with the outer peripheral surface of the housing body 1. ing. The frame 2a is joined to the filter material 2b by bending a plate material made of an aluminum alloy by a predetermined process such as pressing, and then bending the plate material 2b so as to grip the outer peripheral portion of the filter material 2b. In this frame 2a, four square holes 18 corresponding to the circular fumaroles 3a of the perforated plate 5 and the oblong fumaroles 3b are arranged in three rows of four, respectively.
A total of 12 have been opened.

The filter assembly 2 has two ribs 19 extending axially on the outer peripheral surface of the housing body 1.
It is adapted to be fixed in a state of being fitted between a. A rib 19b having the same shape as these ribs 19a is formed in the center of the surface opposite to the surface on which the filter assembly 2 is provided. These three ribs 19a-1
A screw hole 21 into which a screw 20 for fixing the lid plate 16 is screwed is formed at one end of 9b.

The partition body 7 is composed of an arc-shaped plate portion 7a which is in close contact with the inner surface of the perforated plate 5, and side plate portions 7b having a hook-shaped cross section that hangs from the left and right ends thereof. And the arc-shaped plate portion 7
In b, circular holes 22 having substantially the same size as the circular fumaroles 3a of the perforated plate 5 are arranged in the axial direction so as to correspond thereto. Further, in the left and right side plate portions 7b, communication holes 10 opened toward both sides of the ignition tube 8 are arranged in a line in the axial direction.

The ignition tube 8 is provided with left and right side plate portions 7 of the partition body 7.
Small holes 9 opened between b are arranged in a line in the axial direction,
When an igniter (not shown) connected to the ignition tube 8 is activated in response to an electrical or mechanical signal from the collision detection sensor, an ignition flash is ejected from the small holes 9 all at once, and the gas generating agent around the ignition flash is ejected. It is designed to ignite.

The leg portion 13 is an ignition tube 8 bent in a circular tube shape.
Is extended outward in the radial direction from the seam, and a flange 23 is projectingly provided at the free end thereof on opposite sides. This flange 23 is fitted between a pair of projections 24 formed on the inner surface of the housing body 1 in the axial direction, and the ignition tube /
The leg assembly 14 is adapted to be positioned.

The bottom plate 15 is formed to have substantially the same shape as the cross-sectional contour of the housing body 1, and a boss 25 is projectingly provided on the outer surface thereof. An igniter (not shown) is fitted in the center hole of the boss 25, and a round hole 26 which is aligned with the inner space of the ignition tube 2 is formed on the bottom plate so that the ignition part of the igniter can be exposed inside the ignition tube 2. It is opened in the central part of 15.

The lid plate 16 has the same shape as the bottom plate 15,
A central hole 28, through which a stud bolt 27 inserted into the ignition tube 8 of the ignition tube / leg assembly 14 is inserted, is formed at the center thereof, and a rib 19a of the housing body 1 is provided.
-Three ear pieces 30 provided with screw insertion holes 29 are provided at positions corresponding to 19b. A gasket 3 having the same shape as the lid plate 16 is provided between the lid plate 16 and the housing body 1.
1 is sandwiched.

A stud bolt 27 protruding from the cover plate 16
At the tip of the lock nut 32 and lock nut 33
The stud bolt 2 can be screwed on.
The inflator can be attached to the inside of the airbag (not shown) via the boss 7 and the boss 25 provided on the outer surface of the bottom plate 15. The stud bolt 27 and the central hole 28 of the lid plate 16 through which the stud bolt 27 is inserted are not necessary depending on how the stud bolt 27 is mounted in the airbag.

These porous plate 5, partition 7, ignition tube / leg assembly 14, frame 2a of the filter assembly 2,
As the aluminum alloy plate material used as the material for each member of the bottom plate 15, a brazing sheet having a brazing material coated on both sides or one side in advance is adopted. Therefore, the perforated plate 5, the partition 7, and the ignition tube / leg assembly 14 which are formed in a predetermined shape are inserted into the housing main body 1 and the stud bolts 27 are inserted into the ignition tube 8 to insert the filter assembly 2 and the bottom plate. When 15 is positioned and then placed in a heating furnace, the brazing material is melted and the members are brazed together and integrated. After this, the boss 25 of the bottom plate 15
As shown in FIG. 4, an igniter is attached to the ignition tube 8 and an ignition agent is loaded inside the ignition tube 8 and a gas generating agent is loaded in each of the combustion chambers 6a to 6c, and the lid plate 16 and the gasket 31 are screwed. Complete inflator IF.

Also in this embodiment, as shown in FIG. 3, the communication holes 10 provided in the partition body are respectively provided in the third quadrant and the fourth quadrant with respect to the center O of the first combustion chamber 6a. Has been.

The present invention is not limited to the housing having the elliptical cross section as described above, and any contour shape such as a perfect circular contour or a polygonal contour may be used as long as it is line symmetrical. Further, it is equally applicable to the case of removing the leg portion 13 in the embodiment shown in FIG. 2 and subsequent figures and forming two combustion chambers.

[0026]

As described above, according to the present invention, it is possible to optimize the position of the communication hole for radiating the flame from the first combustion chamber directly communicating with the ignition tube to the other combustion chamber, and thus the first combustion The flame of the chamber can be propagated to other combustion chambers evenly, and a great effect can be achieved in improving the gas generation efficiency.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a basic embodiment of a housing of an airbag inflator constructed according to the present invention.

FIG. 2 is an exploded perspective view of an inflator to which the present invention has been applied.

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

FIG. 4 is a perspective view showing a completed form of the inflator shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing body 2 Filter assembly 3 Fume hole 4 Window hole 5 Perforated plate 6 Combustion chamber 7 Partition body 8 Ignition tube 9 Small hole 10 Communication hole 13 Leg part 14 Ignition pipe / leg part assembly 15 Bottom plate 16 Lid plate 17 Ridge 18 square Hole 19a / 19b Rib 20 Screw 21 Screw hole 22 Round hole 23 Flange 24 Projection 25 Boss 26 Round hole 27 Stud bolt 28 Center hole 29 Screw insertion hole 30 Ear piece 31 Gasket 32 Seat nut 33 Lock nut

Claims (1)

[Claims] 1. A housing is partitioned into a plurality of combustion chambers, and when a gas generating agent in the first combustion chamber is ignited by an igniter, the combustion gas thereof is ejected into an air bag from a fumarole provided in the housing. On the other hand, the air generated by igniting the gas generating agent in the other combustion chambers by the flame of the gas generating agent in the first combustion chamber and ejecting the combustion gas of the gas generating agent into the air bag from another fumarole. In a bag inflator, a straight line passing through a center of the first combustion chamber and a center of an ignition flame radiating hole is defined as a y-axis, and a straight line orthogonal to the y-axis and passing through a center of the first combustion chamber is defined as an x-axis. In this case, a communication hole for flame radiation from the first combustion chamber to another combustion chamber is provided in the third quadrant and the fourth quadrant with respect to the center of the first combustion chamber. Inflator.