JPH1159318A - Gas generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the safety of an air bag by defining two combustion chambers at the upper and lower sides of a housing, and providing each combustion chamber with a gas generating agent, a filter member and an ignition device. SOLUTION: First of all, the flame from an ignition device 7 is jetted into an upper combustion chamber 2, whereby the gas generating agent 5 is ignited and burned to generate a high-temperature gas. When the gas pressure reaches a specific pressure, a burst plate 18 is ruptured, and the air bag slowly starts its expansion only by the gas generated from the upper combustion chamber 2. Continuously when an ignition device 8 of a lower combustion chamber 3 is operated, the burning of the gas generating agent 5 in a lower combustion chamber 3 is started, the burst plate 18 is ruptured, and a clean gas is discharged into the air bag. As the result thereof, the air bag slowly starts its expansion by a small amount of gas generated only in the upper combustion chamber 2 in the initial period of the expansion, and then it is rapidly expanded by a large amount of gas generated in the upper and lower combustion chambers 2, 3 after a specific time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas generator used for an airbag for a driver's seat of a motor vehicle, and more particularly to a gas generator capable of controlling deployment of an airbag.

[0002]

2. Description of the Related Art A gas generator for inflating and deploying an airbag at a high speed in order to protect an occupant from an impact caused by a collision of an automobile is incorporated in an airbag module mounted in a steering wheel. In the event of a collision, a high-pressure gas is rapidly generated by a signal from a collision sensor.

As an example of a gas generator for inflating and deploying an airbag, as shown in FIG. 5, friction between an inner cylinder and an outer cylinder of upper and lower lids 51 and 52 having a closed double pipe structure is brought into contact with each other. A housing 50 in which an annular closed space is formed by being pressed against each other, and a gas generating agent 53 and a cylindrical filter 54 are sequentially housed in the closed space of the housing 50 from the inner cylinder to the radially outer side. is there. Further, an ignition device 55 ignited by a collision detection signal from a collision sensor and a transfer agent 56 ignited by the ignition of the ignition device 55 are arranged in the inner cylinder. Then, the gas generator uses the igniter 55 according to the collision detection signal from the collision sensor.
Is ignited, the transfer medium 56 is ignited by this flame, and the flame of the transfer medium 56 is blown out into the closed space through the through hole 57 of the inner cylinder to ignite and burn the gas generating agent 53, Generates a large amount of hot gas rapidly. A large amount of high-temperature gas suddenly generated in the housing 50 flows into the cylindrical filter 54, where the high-temperature gas is cooled and slag collected, and is discharged from the plurality of gas discharge holes 51 a of the upper lid 51 to the airbag. Is rapidly expanded and deployed.

[0004]

However, in such a conventional gas generator, a large amount of gas is released by a collision detection signal from a collision sensor, whereby the airbag is rapidly inflated. Regardless of the type of collision (low-speed collision, high-speed collision, etc.), the vehicle always had a fixed deployment mode. Therefore, when the occupant of the automobile is in the vicinity of the steering wheel or in a case other than the standard case such as a relatively gentle collision mode, the occupant is impacted by the rapidly deployed airbag (punching phenomenon). However, there has been a problem that the occupant may even be obstructed by this, and the original function of the airbag for protecting the occupant cannot be exhibited.

SUMMARY OF THE INVENTION The present invention has been made to solve this problem, and it is possible to control the deployment of the airbag slowly at the initial stage of deployment and thereafter to deploy the airbag quickly. It is an object of the present invention to provide a gas generator capable of improving the safety of a gas generator.

[0006]

In order to solve the above-mentioned problems, in the gas generator according to the present invention, two combustion chambers are defined on the upper and lower sides in the axial direction of the housing, and the gas is contained in each combustion chamber. By arranging the generator, the filter member and the igniter individually, it is possible to operate each igniter with a time lag, whereby only one combustion chamber can be used in the initial stage of the deployment of the airbag. The multi-stage deployment control allows the gas to be developed slowly by the generated gas and then rapidly expanded by adding the gas generated in another combustion chamber.

Preferably, each of the ignition devices is inserted into each combustion chamber from the bottom of the lower combustion chamber. In this arrangement, each ignition device is connected to the center line of the housing in consideration of the balance of the steering wheel. And a method in which the ignition device of the upper combustion chamber is disposed coaxially with the center line of the housing and penetrates the lower combustion chamber in consideration of the strength of the housing.

Further, by providing the housing with a flange member having a cylindrical portion against which gas ejected from each of the gas discharge holes opened to the lower combustion chamber collides, the lower combustion chamber close to the airbag mounting portion is provided. The jetted high-temperature gas is prevented from jetting directly toward the airbag, and slag in the gas can be attached and removed by collision with the cylindrical portion.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The gas generator of the present invention will be described below in detail with reference to FIGS. 1 to 4. In the gas generator of the present invention, the inside of a housing is divided into two upper and lower combustion chambers. Then, the gas generator stored in each combustion chamber can be independently ignited by an ignition device arranged in each combustion chamber, whereby the deployment form of the airbag can be controlled. For example, by igniting the gas generating agent in each combustion chamber with a time lag, a multi-stage in which the air bag is gradually expanded with a small amount of gas in the initial stage of the deployment of the airbag and then rapidly expanded by adding the gas thereafter. It has output characteristics. Hereinafter, two types of gas generators used for the driver's seat airbag, those shown in FIGS. 1 and 2 and those shown in FIGS. 3 and 4, will be described.

First, a gas generator X of an airbag for a driver's seat shown in FIGS. 1 and 2 has a short cylindrical housing 1 and the inside of the housing 1 defined in two upper and lower combustion chambers 2 and 3. And the igniters 7 and 8 for independently igniting the gas generating agent 5 and the filter member 6 and the gas generating agent 5 in each of the combustion chambers 2 and 3, respectively. Have.

The housing 1 has a structure in which an upper lid 9 and a lower lid 10 are joined by butt welding (for example, friction welding) to form a combustion chamber as a closed space inside. The upper lid 9 of the housing 1 includes a short cylindrical portion 9 a and the short cylindrical portion 9.
a having a closed cylindrical shape composed of an upper plate 9a for closing one end of a. The lower lid 10 has a bottomed cylindrical shape including an outer cylinder part 11 and a bottom plate 12 closing one end of the outer cylinder part 11, and the short cylindrical part 9a of the upper lid and the outer cylinder part 11 of the lower lid are formed. The and form the cylindrical body of the housing. Also, the bottom plate 12
Are provided with two long and short fixed inner cylinders 15 and 16 at a symmetrical portion in a radially outer direction with respect to the axis. The long fixed inner cylinder 15 projects through the partition member 4 into the upper combustion chamber 2, and the short fixed inner cylinder 16 projects into the lower combustion chamber 3. Further, the outer cylinder portion 11 is formed with two rows of gas discharge holes 11a opened to the upper and lower combustion chambers 2 and 3, and the inner peripheral surface of each gas discharge hole 11a has moisture proofness inside the housing 1 and moisture elimination. A thin cylindrical burst plate 18 is adhered and closed to adjust the internal pressure during combustion.

Further, a flange member 30 is provided outside the lower cover 10, and the flange member 30 includes a bottom plate 30 a fixed to the outside of the bottom plate 12 of the lower cover 10 or the outer cylindrical portion 11. A cylindrical portion 30b extending from the outer peripheral edge of the bottom plate 30a to the upper lid 9 side, and a flange portion 30c bent radially outward from the tip of the cylindrical portion 30b are integrally formed by press working. It faces each gas discharge hole 11a opened in the combustion chamber 3 with a space.

The housing 1 is provided with a cylindrical portion 9 of the upper lid 9.
a and the outer cylinder part 11 of the lower lid 10 are joined by butt friction welding to form a cylindrical body part, thereby forming a sealed space inside. The enclosed space of the housing 1
The upper combustion chamber 2 and the lower combustion chamber 3 are divided into two combustion chambers by a partition member 4 arranged in parallel with the upper plate 9a and the bottom plate 12. The partition member 4 is the outer cylindrical portion 1 of the lower lid 10.
1 is a disc-like shape which can be press-fitted therein, and a through hole 1 through which a long fixed inner cylinder 15 penetrates a portion eccentric from its axis.
7 are formed. Then, the partition member 4 is connected to the outer cylindrical portion 11.
The through-hole 17 is fitted into the long fixed inner cylinder 15, and is brought into contact with the step 11 b of the outer cylinder 11 and the tip step 15 a of the long fixed inner cylinder 15. Two combustion chambers 2 and 3 are defined on the upper and lower sides of the direction so as to isolate each other. Thus, the long fixed inner cylinder 15 penetrates through the lower combustion chamber 3 and the partition member 4 and protrudes into the upper combustion chamber 2, and the short fixed inner cylinder 16 protrudes into the lower combustion chamber 3. Each of the combustion chambers 2 and 3 is loaded with a gas generating agent 5,
The filter member 6 is arranged so as to surround this, and each of the gas discharge holes 11a is opened.

Each of the filter members 6 has a cylindrical shape so as to be disposed along the peripheral wall of each of the combustion chambers 2 and 3, and has an annular gas passage between the filter member 6 and the inner peripheral surface of the outer cylinder 11. It is formed with an outer diameter dimension such that a space S is formed, and is disposed on the partition member 4 of the upper combustion chamber 2 and on the bottom plate 12 of the lower combustion chamber 3, respectively. The filter member 6 in the upper combustion chamber 2 includes a partition member 4
The filter member 6 in the lower combustion chamber 3 extends from the bottom plate 12 until it contacts the partition member 4. Between the gas generating agent 5 and the partition member 4 in the lower combustion chamber 3, a cushion member 19 that is in contact with the partition member 4 is disposed, and the cushion member 19 is pulverized by vibration of the gas generating agent 5. It has a function of both heat prevention and heat insulating material for blocking heat transfer between the combustion chambers 2 and 3. Therefore, as the cushion member 19, a member having a heat insulating function such as a ceramic fiber is preferably used. Reference numeral 20 denotes a cushion member disposed between the gas generating agent 5 of the upper combustion chamber 2 and the upper plate 9b.
It has the function of preventing powdering due to vibration of Therefore, it is preferable to use an elastic material such as silicone rubber or silicone foam as the cushion member 20, but a material having a heat insulating function such as the ceramic fiber may be used.

The ignition devices 7 and 8 are provided with a lower holding portion 22A.
And an ignition portion 22B arranged at the tip,
It is arranged in each of the fixed inner cylinders 15 and 16. Each of the ignition devices 7 and 8 is air-tightly abutted to a tapered step 23 formed in each of the fixed inner cylinders 15 and 16 via a seal member 25 (O-ring). The crimping portion 24 on the distal end side of 16 is crimped and fixed by bending inward. Thereby, the ignition device 7 of the long fixed inner cylinder 15 has its ignition portion 22B protruded into the upper combustion chamber 2 and is fixed.
On the other hand, the ignition device 8 in the short fixed inner cylinder 16 is
2B protrudes into the lower combustion chamber 3 and is fixed. or,
Each of the ignition devices 7 and 8 is connected to a collision sensor (not shown) via a wiring.

Next, the operation of the gas generator X will be described. When the collision sensor detects the collision of the automobile, first, the ignition device 7 of the upper combustion chamber 2 is operated, and the flame from the ignition device 7 is jetted into the upper combustion chamber 2, and the gas generating agent 5 is ignited by the flame. Combustion produces hot gas.
The high-temperature gas generated in the combustion chamber 2 is supplied to the cushion member 19.
In a state in which heat transfer to the adjacent lower combustion chamber 3 is cut off via the heat insulating material, the gas flows into the filter member 6, and the slag is collected and cooled by the filter member 6 so that the gas passage space S
When the gas pressure flowing into the combustion chamber 2 and rising with the combustion of the gas generating agent 5 in the combustion chamber 2 reaches a predetermined pressure, the burst plate 18 is broken, and the clean gas uniformized in the gas passage space S is The discharge to the airbag is started from each of the gas discharge holes 11a, and the airbag gradually starts to deploy only by the gas generated from the upper combustion chamber 2.

Subsequently, when the ignition device 8 of the lower combustion chamber 3 is operated with a small time difference after the combustion of the upper combustion chamber 2 starts, the combustion of the gas generating agent 5 in the lower combustion chamber 3 starts, and As in the case of the combustion chamber 2, the burst plate 18 is broken by the increase in the gas pressure, and the clean gas uniformized in the gas passage space S is discharged from the gas discharge holes 11a to the airbag. At this stage, the airbag is deployed by a large amount of high-pressure gas in which both the gas released from the upper combustion chamber 2 and the gas released from the lower combustion chamber 3 are merged. become. As a result, in the early stage of deployment, the airbag starts gently inflating with a small amount of gas generated only in the upper combustion chamber 2, and after a predetermined time, a large amount of gas generated in the vertical combustion chambers 2, 3 It will expand and expand more rapidly.

The gas discharge holes 1 opened in the lower combustion chamber 3
The gas released from the air bag 1a to the air bag is supplied to the flange member 3 disposed at a position surrounding the gas release hole 11a.
The slag in the gas adheres to the cylindrical portion 30b and is collected. The gas released from the lower combustion chamber 3 acts after the gas released from the upper combustion chamber 2 starts deployment of the airbag (that is, after the airbag is disengaged from the gas generator in the direction in which it is released). Therefore, the bag attack due to the gas flow toward the axial direction is suppressed.

As described above, according to the gas generator X, by operating each of the ignition devices 7 and 8 with a time lag, the deployment of the airbag is moderated by the gas generated only from the upper combustion chamber 2 in the initial stage. The deployment control is performed so that deployment is rapidly performed by a large amount of gas generated from both combustion chambers 2 and 3 (the amount of gas released to the airbag is controlled in two stages). Even if the occupant is seated near the steering wheel, the original function of the airbag can be exhibited safely without receiving the impact due to the rapid inflation in the early stage of deployment of the airbag.

When the gas discharge holes 11a of the outer cylinder portion 11 are covered by the flange member 30 from the outside, the gas discharged from the lower combustion chamber 3 collides with the cylindrical portion 30b of the flange member 30. The slag in the gas adheres to the cylindrical portion 30a by this collision, and a further cooling effect can be achieved, so that thermal melting of the airbag can be prevented.

Further, the ignition order of each of the combustion chambers 2 and 3 is as follows.
When the lower combustion chamber 3 is ignited after the upper combustion chamber 2 is ignited, the gas released from the lower combustion chamber 3 is generated by the gas flow already released from each gas discharge hole 11a of the upper combustion chamber 2. Since the airbag has started to inflate, the bag attack due to the gas flow toward the occupant in the axial direction is suppressed, and the airbag can be inflated and deployed stably. The order of gas generation by the combustion chambers 2 and 3 is as follows.
The present invention is not limited to the above description. The upper combustion chamber 2 may be ignited after the lower combustion chamber 3 is ignited. Depending on the collision type of the automobile, the combustion chambers 2 and 3 are ignited at the same time to inflate the airbag. , There is also a method to expand.

The positions of the igniters 7 and 8 are set symmetrically with respect to the axis as shown in FIG.
Since the left and right balance of the gas generator is balanced, when the gas generator is mounted on the steering wheel, instability due to the eccentricity of the position of the center of gravity of the steering wheel is eliminated.

Next, the gas generator Y of the driver's seat airbag shown in FIGS. 3 and 4 is different from the gas generator X shown in FIGS. Fixed inner cylinder 1
5 is arranged at the center of the shaft center and joined to the upper plate 9b of the upper lid 9, and the same reference numerals as those in FIGS. 1 and 2 denote the same members, and redundant description will be omitted.

3 and 4, the upper cover 9 of the housing 1 has a short inner cylindrical portion 9c formed at the center of the axis thereof. The bottom plate 12 of the lower cover 10 is provided with a long fixed inner cylinder 15 at the center of the shaft. And the housing 1
Abuts the cylindrical portion 9a with the outer cylindrical portion 11 and the inner cylindrical portion 9c with the long fixed inner cylinder 15 so as to cover the open end of the lower cover 10 from the open end of the upper cover 9 and joins them by friction welding. Thus, an annular closed space is formed. Further, the partition member 4 has a through hole 17 formed at the center thereof for penetrating the long fixed inner cylinder 15. The through hole 17 is press-fitted into the outer cylinder part 11, and the through hole 17 is moved outside the fixed inner cylinder 15. The two combustion chambers 2, 2 are provided on the upper and lower sides in the axial direction of the housing 1 by being fitted and in contact with the step portions 11b and 15a of the outer cylinder portion 11 and the long fixed inner cylinder 15.
3 are defined. Further, the ignition device 7 arranged in the long fixed inner cylinder 15 has the holding portion 22A in airtight contact with the tapered step portion 23 through the seal member 23 (O-ring), and the caulking portion 24 It is fixed by caulking.
Thereby, the ignition device 7 has its ignition portion 22B protrudingly arranged in an ignition space G defined by the long fixed inner cylinder 15 and the upper plate 9b, and the ignition space G is a long fixed space. A plurality of through holes 15b formed in the circumferential direction of the inner cylinder 15
Through the upper combustion chamber 2.

Also in the gas generator Y having such a structure, the deployment of the airbag can be controlled in two stages as described with reference to FIGS. 1 and 2 by igniting the ignition devices 7 and 8 with a time difference. Therefore, even in a low-speed collision or when the occupant in the driver's seat is not properly seated, the original function of the airbag can be safely performed without receiving a collision in the initial stage of deployment of the airbag.

The fixed inner cylinder 1 protruding into the upper combustion chamber 2
When the structure 5 is joined to the upper plate 9c of the upper lid 9, the structural strength of the housing 1 is increased, so that it is possible to generate a large amount of gas and adapt to a large-sized gas generator with high pressure. Become. In particular, when the long fixed inner cylinder 15 joined to the upper lid 9 of the housing 1 is provided at the center of the axis of the bottom plate 12 of the lower lid 10, one of the upper lid 10 or the lower lid 12 is fixed and the other is rotated. There is an advantage that the fixed inner cylinder 15 can be friction-welded to the inner cylinder portion 9c of the upper lid 10 at the same time when performing friction welding.

Although not shown, it is possible to provide a projection on the upper lid 9 to cover the outer friction pressure contact portion (for example, by turning the flange member 30 attached to the lower lid 10 in the opposite direction). And the like, and attached to the upper lid 9), which is effective in preventing damage to the airbag due to burrs generated during friction welding.

[0028]

As described above, according to the gas generator of the present invention, two combustion chambers are formed inside the housing on the upper and lower sides in the axial direction, and the gas generating agent and the filter member are provided in each combustion chamber. And the ignition devices that can be operated independently of each other are arranged, so that it is possible to operate each ignition device with a time difference, and therefore, the time difference between the combustion of the gas generating agent in each combustion chamber and the time difference. And multistage deployment control in which the airbag is deployed gently in the early stage of airbag deployment with a small amount of gas generated in only one combustion chamber, and then the airbag is rapidly deployed by adding gas generated in other combustion chambers. Can be performed. As a result, even when the occupant in the driver's seat is seated near the steering wheel, the original function of the airbag can be exhibited safely without being subjected to an impact due to the initial deployment of the airbag.

Further, if the long fixed inner cylinder projecting into the upper combustion chamber is structured to be joined to the upper plate of the upper lid, the structural strength of the housing is increased, so that a large amount of gas is generated.
It is possible to adapt to a large-sized gas generator with high pressure.

Further, when a flange member having a cylindrical portion surrounding each gas discharge hole opened into the lower combustion chamber is arranged in the housing, gas ejected from each gas discharge hole collides with the cylindrical portion, and this collision occurs. As a result, the slag in the gas is cooled and adhered to and removed from the cylindrical portion, so that slag collection and gas cooling can be further improved.

Further, after the gas is generated by the combustion of the gas generating agent in the upper combustion chamber, the gas generation control is performed such that the gas is generated by the combustion of the gas generating agent in the lower combustion chamber. The gas released from the airbag has already been released into the airbag from the gas discharge holes in the upper combustion chamber, so that the airbag is inflated, thereby suppressing damage to the ebag by the hot gas flow toward the occupant. As a result, the airbag can be deployed stably.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a gas generator of the present invention used for an airbag for a driver's seat.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view showing another gas generator of the present invention.

FIG. 4 is a sectional view taken along line BB of FIG. 3;

FIG. 5 is a sectional view showing a gas generator used in a conventional driver airbag.

[Description of Signs] 1 Housing 2 Upper combustion chamber 3 Lower combustion chamber 4 Partition member 5 Gas generating agent 6 Filter member 7, 8 Ignition device 9 Upper lid 9a Cylindrical part 9b Upper plate 10 Lower lid 11 Outer cylinder part 11a Gas release Hole 12 Bottom plate 15 Long fixed inner cylinder 16 Short fixed inner cylinder

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Koji Tanaka 3903-39, Tomimachi, Himeji-shi, Hyogo Pref. 3903-39, Toyotomi-cho, Himeji-shi, Japan Nippon Kayaku Co., Ltd. Himeji Plant Sensor Technology Co., Ltd. Himeji Technical Center

Claims (7)

[Claims] 1. A short cylindrical body (9a, 11),
In a short-cylindrical gas generator in which a combustion chamber is defined by an upper plate (9b) and a bottom plate (12) for closing the upper and lower ends thereof, the combustion chamber is divided into upper combustion chambers by a partition member (4). A chamber (2) and a lower combustion chamber (3) are defined, and the upper combustion chamber (2) and the lower combustion chamber (3) surround the gas generating agent (5). Ignition devices (7, 8) that operate independently of each other together with the filter member (6) are provided and arranged, and the upper and lower combustion chambers (2, 2) are provided in the cylindrical body (11).
A gas generator characterized in that a plurality of gas discharge holes (11a) each opening to (3) are formed. 2. The gas generator according to claim 1, wherein said ignition devices (7, 8) are inserted into said upper and lower combustion chambers (2, 3) from said bottom plate (12) side. 3. The gas generator according to claim 1, wherein the ignition devices (7, 8) are arranged symmetrically with respect to a center line of the cylindrical body (11). 4. The igniter (7) of the upper combustion chamber (2) is arranged on the same axis as the center line of the cylindrical body (11) and penetrates the lower combustion chamber (3). The gas generator according to claim 1 or 2, wherein 5. A flange member having a cylinder upper part (30b) surrounding a gas discharge hole (11a) opened in the lower combustion chamber (3) is attached. Gas generator 6. A closed cylindrical upper lid (9) comprising a short cylindrical portion (9a) and an upper plate (9b) closing one end thereof.
And a bottomed cylindrical lower lid (10) consisting of an outer cylinder (11) and a bottom plate (12) closing one end thereof, and a housing formed by butt-joining these upper and lower lids (9, 10). (1), a partition member (4) is arranged inside the housing (1), and two combustion chambers (2, 3) are defined above and below in the cylindrical axis direction. , 3), respectively, gas generating agent (5),
A cylindrical filter member (6) and an igniter (7, 8) surrounding the lower cover (10) are disposed on the bottom plate (12) of the lower lid (10). A long fixed inner cylinder (16) that penetrates through the lower combustion chamber (3) and the partition member (4) and projects into the upper combustion chamber (2). The ignition devices (7, 8) for respectively igniting the gas generating agents (5) in the combustion chambers (2, 3) are arranged in the fixed inner cylinders (15, 16), respectively. A plurality of gas discharge holes (11) opening to each of the combustion chambers (2, 3) are formed in an outer cylindrical portion (11) of the lower lid (10).
Gas generator characterized by forming a) 7. The long fixed inner cylinder (15) is disposed at the center of the bottom plate (12) of the lower cover (10), and extends to the upper plate (9b) of the upper cover (9). The gas generator according to claim 6, which is butt-joined to the upper lid.