JP3702074B2 - Gas generator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas generator used in an airbag for a driver's seat of an automobile, and more particularly to a gas generator that enables airbag deployment control.
[0002]
[Prior art]
A gas generator for inflating and deploying an air bag at high speed is installed in an air bag module mounted in the steering wheel to protect the occupant from the impact caused by a car crash. In this type, high-pressure gas is rapidly generated by a signal from a collision sensor.
[0003]
As an example of a gas generator for inflating and deploying an air bag, as shown in FIG. 5, the inner cylinder and the outer cylinder of the upper and lower lids 51 and 52 having a double tube structure with a lid are brought into contact with each other and subjected to friction welding. And a gas generating agent 53 and a cylindrical filter 54 are sequentially housed in the sealed space of the housing 50 from the inner cylinder toward the outer diameter. An igniter 55 that is ignited by a collision detection signal from a collision sensor and a transfer agent 56 that is ignited by ignition of the igniter 55 are disposed in the inner cylinder. The gas generator ignites the igniter 55 by the collision detection signal from the collision sensor, ignites the transfer agent 56 with this flame, and further passes the flame of the transfer agent 56 through the passage hole 57 of the inner cylinder. Then, the gas generating agent 53 is ignited and burned, and a large amount of high-temperature gas is rapidly generated. A large amount of high-temperature gas generated abruptly in the housing 50 flows into the cylindrical filter 54, where it is cooled and collected by the slag, and is discharged from the plurality of gas discharge holes 51 a of the upper lid 51 to the airbag. Is designed to rapidly expand and deploy.
[0004]
[Problems to be solved by the invention]
However, in such a conventional gas generator, a large amount of gas is released by a collision detection signal from the collision sensor, and thereby the airbag is rapidly inflated. Etc.), it always had a certain form of deployment. Therefore, when the vehicle occupant 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 shocked by a rapidly deployed airbag (punching phenomenon). However, even when the occupant is damaged by this, there is a problem that the original function of the airbag protecting the occupant cannot be exhibited.
[0005]
The present invention has been made to solve this problem, and enables deployment control in which an airbag is slowly deployed at an early stage of deployment and then rapidly deployed, thereby improving the safety of the airbag. The object is to provide a gas generator capable of improving the efficiency.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, in the gas generator according to the present invention, two combustion chambers are defined inside the housing on the upper and lower sides in the axial direction, and a gas generating agent, a filter member, and an ignition device are provided in each combustion chamber. Each of the igniters can be operated with a time difference by being configured to be arranged in each, and thereby, it is gently deployed by gas generated in only one combustion chamber at the initial stage of deployment of the airbag, After that, multistage deployment control that allows rapid deployment by adding gas generated in other combustion chambers is enabled.
[0007]
The ignition devices are preferably inserted into the combustion chambers from the bottom of the lower combustion chamber. In this arrangement, the ignition devices are arranged with respect to the center line of the housing in consideration of the balance of the steering wheel. There are a method of arranging in a symmetrical position and a method of arranging an ignition device for the upper combustion chamber through the lower combustion chamber on the same axis as the center line of the housing in consideration of the strength of the housing.
[0008]
Further, by providing the housing with a flange member having a cylindrical portion that collides with the gas ejected from each gas discharge hole that opens to the lower combustion chamber, a high temperature ejected from the lower combustion chamber close to the mounting portion of the airbag. It is possible to prevent the gas from being directly ejected toward the airbag, and to attach and remove slag in the gas by collision with the cylindrical portion.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the gas generator of the present invention will be described in detail with reference to FIGS. 1 to 4. The gas generator of the present invention defines a housing in two upper and lower combustion chambers and is accommodated in each combustion chamber. The gas generating agent to be fired can be ignited independently by an ignition device disposed in each combustion chamber, so that 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, it can be deployed in a multistage manner in which it is gradually deployed with a small amount of gas at the beginning of deployment of the airbag and then rapidly deployed with the addition of subsequent gases. It has an output characteristic. Hereinafter, two types of gas generators used in the driver's seat airbag, that is, those shown in FIGS. 1 and 2 and those shown in FIGS. 3 and 4 will be described.
[0010]
First, a gas generator X of an airbag for a driver's seat shown in FIGS. 1 and 2 includes a short cylindrical housing 1 and a partition member that defines the inside of the housing 1 into two combustion chambers 2 and 3 on the upper and lower sides. 4, and gas generating agent 5 and filter member 6 accommodated in each combustion chamber 2, 3 and ignition devices 7, 8 for igniting the gas generating agent 5 in each combustion chamber 2, 3 independently. .
[0011]
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 sealed space therein. The upper lid 9 of the housing 1 has a covered cylindrical shape including a short cylindrical portion 9a and an upper plate 9a that closes one end of the short cylindrical portion 9a. The lower lid 10 has a bottomed cylindrical shape composed of an outer cylindrical portion 11 and a bottom plate 12 that closes one end of the outer cylindrical portion 11, and the short cylindrical portion 9 a of the upper lid and the outer cylindrical portion 11 of the lower lid. And the cylindrical body of the housing is formed. The bottom plate 12 is provided with two long and short fixed inner cylinders 15 and 16 at symmetrical portions in the radially outward direction with respect to the axis. The long fixed inner cylinder 15 penetrates 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. In addition, the outer cylinder portion 11 is formed with two rows of gas discharge holes 11a that open to the upper and lower combustion chambers 2 and 3. The inner peripheral surface of each gas discharge hole 11a is provided with moisture-proofing in the housing 1. In order to adjust the internal pressure during combustion, a thin cylindrical burst plate 18 is stuck and closed.
[0012]
Further, a flange member 30 is provided on the outer side of the lower lid 10, and the flange member 30 includes a bottom plate 30a fixed to the outer side of the bottom plate 12 or the outer cylinder portion 11 of the lower lid 10, and the bottom plate 30a. A cylindrical portion 30b extending from the outer peripheral edge of the cylindrical portion 30b to the upper lid 9 side and a flange portion 30c bent outward from the tip of the cylindrical portion 30b are integrally formed by pressing, and the cylindrical portion 30b is formed in the lower combustion chamber 3. It faces each gas discharge hole 11a opened at a distance.
[0013]
The housing 1 has a cylindrical body portion formed by joining the cylindrical portion 9a of the upper lid 9 and the outer cylindrical portion 11 of the lower lid 10 by butt friction welding, thereby forming a sealed space inside. The sealed space of the housing 1 is defined in two combustion chambers, an upper combustion chamber 2 and a lower combustion chamber 3, by a partition member 4 arranged in parallel with the upper plate 9 a and the bottom plate 12. The partition member 4 has a disk shape that can be press-fitted into the outer cylinder portion 11 of the lower lid 10, and a through-hole 17 that allows the long fixed inner cylinder 15 to pass through is formed in a portion that is eccentric from the axis. Yes. The partition member 4 is press-fitted into the outer cylinder portion 11, and the through hole 17 is fitted into the long fixed inner cylinder 15, so that the step portion 11 b of the outer cylinder portion 11 and the tip step portion 15 a of the long fixed inner cylinder 15 are inserted. The two combustion chambers 2 and 3 are separated from each other on the upper and lower sides of the housing 1 in the axial direction. Thereby, the long fixed inner cylinder 15 penetrates 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 combustion chamber 2, 3 is loaded with a gas generating agent 5, a filter member 6 is disposed so as to surround it, and each gas discharge hole 11 a is opened.
[0014]
Each filter member 6 has a cylindrical shape so as to be disposed along the peripheral wall portion of each combustion chamber 2, 3, and an annular gas passage space S is formed between the inner peripheral surface of the outer cylinder portion 11. The outer diameter dimensions of the upper combustion chamber 2 and the bottom plate 12 of the lower combustion chamber 3 are respectively arranged on the partition member 4 of the upper combustion chamber 2. The filter member 6 in the upper combustion chamber 2 extends from the partition member 4 until it abuts on the upper plate 9 b, and the filter member 6 in the lower combustion chamber 3 extends from the bottom plate 12 until it abuts on 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 contacts the partition member 4 is disposed, and the cushion member 19 is pulverized by vibration of the gas generating agent 5. It has both the function of a heat insulating material that prevents the heat transfer between the combustion chambers 2 and 3. Therefore, as the cushion member 19, a member having a heat insulating function such as ceramic fiber is preferably used. Reference numeral 20 denotes a cushion member disposed between the gas generating agent 5 in the upper combustion chamber 2 and the upper plate 9b, and has a function of preventing pulverization due to vibration of the gas generating agent 5. Therefore, the cushion member 20 is preferably made of an elastic material such as silicon rubber or silicon foam, but may have a heat insulating function such as the ceramic fiber.
[0015]
The ignition devices 7 and 8 include a lower holding portion 22A and an ignition portion 22B disposed at the tip, and are disposed in the fixed inner cylinders 15 and 16, respectively. Each ignition device 7, 8 is brought into airtight contact with a tapered step portion 23 formed in each fixed inner cylinder 15, 16 via a seal member 25 (O-ring), and each fixed inner cylinder 15, The crimping portion 24 on the tip end side of the 16 is bent inward to fix it. As a result, the ignition device 7 of the long fixed inner cylinder 15 has its ignition part 22B protruding and fixed into the upper combustion chamber 2, while the ignition device 8 in the short fixed inner cylinder 16 has its ignition part 22B below. It protrudes into the side combustion chamber 3 and is fixed. The ignition devices 7 and 8 are connected to a collision sensor (not shown) via wiring.
[0016]
Next, the operation of the gas generator X will be described. When the collision sensor detects a collision of the automobile, first, the ignition device 7 of the upper combustion chamber 2 is operated, the flame from the ignition device 7 is jetted into the upper combustion chamber 2, and the gas generating agent 5 is ignited by this flame. Burn to generate hot gas. The high-temperature gas generated in the combustion chamber 2 flows into the filter member 6 in a state where heat transfer to the adjacent lower combustion chamber 3 is interrupted via the heat insulating material of the cushion member 19, and the filter The burst plate 18 is broken when the gas pressure flowing into the gas passage space S through the slag collecting and cooling by the member 6 and rising as the gas generating agent 5 in the combustion chamber 2 burns reaches a predetermined pressure. The clean gas homogenized in the gas passage space S is started to be released from the gas discharge holes 11a to the airbag, and the airbag starts to be gradually deployed only by the generated gas from the upper combustion chamber 2.
[0017]
Subsequently, when the ignition device 8 of the lower combustion chamber 3 is operated with a slight time difference after the start of combustion in the upper combustion chamber 2, combustion of the gas generating agent 5 in the lower combustion chamber 3 starts, and the upper combustion chamber 2. As in the case of, the burst plate 18 is broken by the increase in gas pressure, and the clean gas uniformized in the gas passage space S is discharged from the gas discharge hole 11a to the airbag. At this stage, since the airbag is deployed by a large amount of high-pressure gas in which both the gas discharged from the upper combustion chamber 2 and the gas discharged from the lower combustion chamber 3 are merged, the airbag is shifted to rapid deployment. become. As a result, the air bag, the initial stage of deployment, to begin gradually inflated by a small amount of gas generated only in the upper combustion chamber 2, from after a predetermined time, a large amount of gas generated in the upper and lower combustion chambers 2 and 3 Will expand and expand rapidly.
[0018]
The gas released to the airbag from the gas discharge hole 11a opened in the lower combustion chamber 3 collides with the cylindrical portion 30b of the flange member 30 arranged at a position surrounding the gas discharge hole 11a. Due to the collision, the slag in the gas adheres to the cylindrical portion 30b and is collected. Further, the gas released from the lower combustion chamber 3 acts after the airbag starts to be deployed by the gas released from the upper combustion chamber 2 (that is, after the airbag is different from the gas generator in the disengagement direction). Therefore, the bag attack due to the gas flow in the axial direction is suppressed.
[0019]
As described above, according to the gas generator X, each of the ignition devices 7 and 8 is operated with a time lag so that the airbag is gently deployed by the gas generated only from the upper combustion chamber 2 in the initial stage. Then, since deployment control is performed to rapidly deploy with 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), the passenger in the driver's seat Even when seated in the vicinity of the steering wheel, the original function of the airbag can be safely performed without being subjected to an impact caused by the rapid expansion of the airbag at the initial stage of deployment.
[0020]
Further, when the gas discharge hole 11a of the outer cylinder portion 11 is covered from the outside by the flange member 30, the gas released from the lower combustion chamber 3 collides with the cylindrical portion 30b of the flange member 30, and by this collision, Since the slag in the gas adheres to the cylindrical portion 30a and a further cooling effect can be achieved, thermal melting of the airbag can be prevented.
[0021]
Furthermore, when the lower combustion chamber 3 is ignited after the upper combustion chamber 2 is ignited as the ignition order of the combustion chambers 2 and 3, the gas released from the lower combustion chamber 3 is already in the upper combustion chamber 2. Since the airbag starts to inflate due to the gas flow discharged from each gas discharge hole 11a, the bag attack due to the gas flow toward the passenger side in the axial direction is suppressed, and the airbag is stably inflated and deployed. It becomes possible. The order of gas generation by the combustion chambers 2 and 3 is not limited to the above description, and the upper combustion chamber 2 may be ignited after the lower combustion chamber 3 is ignited. There is also a system in which the combustion chambers 2 and 3 are simultaneously ignited to inflate and deploy the airbag.
[0022]
Further, as the arrangement positions of the ignition devices 7 and 8, the right and left balance of the gas generator is achieved by arranging the ignition devices 7 and 8 on the object as shown in the drawing, so that the gas generator is attached to the steering wheel. When mounted, instability due to eccentricity of the center of gravity of the steering wheel is eliminated.
[0023]
Next, the gas generator Y of the driver airbag shown in FIGS. 3 and 4 is a long fixed inner cylinder that protrudes into the upper combustion chamber 2 with respect to the gas generator X shown in FIGS. 1 and 2. 15 is arranged in the center of the shaft center and joined to the upper plate 9b of the upper lid 9. The same reference numerals as those in FIGS. 1 and 2 denote the same members, and the duplicated explanation is omitted.
[0024]
3 and 4, the upper lid 9 of the housing 1 has a short inner cylinder portion 9c formed at the center of the axial center. The bottom plate 12 of the lower lid 10 is provided with a long fixed inner cylinder 15 at the center of the shaft. Then, the housing 1 butts the cylindrical portion 9a, the outer cylindrical portion 11, the inner cylindrical portion 9c, and the long fixed inner cylinder 15 so as to cover the opening end of the lower lid 10 from the opening end of the upper lid 9. An annular sealed space is formed by joining by pressure welding. Further, the partition member 4 is formed with a through hole 17 through which the long fixed inner cylinder 15 penetrates at the center thereof. The through hole 17 is press-fitted into the outer cylinder part 11 so that the through hole 17 is outside the fixed inner cylinder 15. The two combustion chambers 2 and 3 are defined on the upper and lower sides in the axial direction of the housing 1 by being fitted and contacting the step portions 11 b and 15 a of the outer cylinder portion 11 and the long fixed inner cylinder 15. . Further, in the ignition device 7 disposed in the long fixed inner cylinder 15, the holding portion 22 </ b> A is hermetically abutted against the tapered step portion 23 via the seal member 23 (O-ring) and the caulking portion 24. It is fixed by caulking. As a result, the ignition device 7 is disposed so that the ignition portion 22B protrudes into the ignition space G defined by the long fixed inner cylinder 15 and the upper plate 9b. It communicates with the upper combustion chamber 2 through a plurality of passage holes 15b formed along the circumferential direction of the inner cylinder 15.
[0025]
Also in the gas generator Y having such a structure, by igniting the ignition devices 7 and 8 with a time difference, the airbag deployment can be controlled in two stages as described with reference to FIGS. Even when a collision or a driver's seat occupant is not properly seated, the original function of the airbag can be safely performed without being subjected to a collision at the initial deployment of the airbag.
[0026]
Further, if the fixed inner cylinder 15 protruding into the upper combustion chamber 2 is joined to the upper plate 9c of the upper lid 9, the structural strength of the housing 1 is increased, so that a large amount of gas is generated and the pressure is increased. It becomes possible to adapt to a large gas generator. In particular, when a long fixed inner cylinder 15 to be 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 and the lower lid 12 is fixed and the other is rotated. Thus, 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.
[0027]
Although not shown, it is possible to provide a protrusion on the upper lid 9 so as to cover the outer friction welding portion (for example, the upper lid with the flange member 30 attached to the lower lid 10 shown in the reverse direction). It is effective in the sense that the airbag is not damaged by burrs generated during friction welding.
[0028]
【The invention's effect】
As described above, according to the gas generator of the present invention, the inside of the housing is formed with two combustion chambers on the upper and lower sides in the axial direction, and the gas generating agent and the filter member are respectively disposed in each combustion chamber. In addition, since the ignition devices that can be operated independently of each other are arranged, it is possible to operate each ignition device with a time difference, and therefore, there is a time difference in the combustion of the gas generating agent in each combustion chamber, and the air bag. In the initial stage of deployment, it is possible to perform multi-stage deployment control in which a small amount of gas generated in only one combustion chamber is gently deployed and then the airbag is rapidly deployed by adding gas generated in other combustion chambers. It becomes. As a result, even when the driver's seat occupant is seated in the vicinity of the steering wheel, the original function of the airbag can be safely performed without receiving an impact due to the initial deployment of the airbag.
[0029]
In addition, if a long fixed inner cylinder protruding into the upper combustion chamber is 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 and the pressure is increased. Adaptation to a gas generator becomes possible.
[0030]
Further, when a flange member having a cylindrical portion surrounding each gas discharge hole opened in the lower combustion chamber is arranged in the housing, the gas ejected from each gas discharge hole collides with the cylindrical portion, and this collision causes the gas to enter the gas chamber. Since the slag is cooled and attached to and removed from the cylindrical portion, further improvement of slag collection and gas cooling can be achieved.
[0031]
Furthermore, if gas generation control is performed such that gas is generated by combustion of the gas generating agent in the upper combustion chamber and then gas is generated by combustion of the gas generating agent in the lower combustion chamber, the gas is released from the lower combustion chamber. Since the airbag is inflated by the gas already released into the airbag from the gas discharge hole of the upper combustion chamber, damage to the airbag due to the hot gas flow toward the passenger is suppressed. The bag can be stably deployed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a gas generator of the present invention used for a driver's seat airbag.
FIG. 2 is a cross-sectional view taken along the line AA of FIG.
FIG. 3 is a cross-sectional view showing another gas generator of the present invention.
4 is a cross-sectional view taken along the line BB in FIG.
[Figure 5]
It is sectional drawing which shows the gas generator used for the conventional driver's seat airbag.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Housing 2 Upper combustion chamber 3 Lower combustion chamber 4 Partition member 5 Gas generating agent 6 Filter members 7, 8 Ignition device 9 Upper lid 9a Cylindrical portion 9b Upper plate 10 Lower lid 11 Outer cylinder portion 11a Gas discharge hole 12 Bottom plate 15 Long Shaft fixed inner cylinder 16 Short fixed inner cylinder

Claims (7)

Deployment of a short cylindrical airbag comprising a short cylindrical cylindrical body (9a, 11), and an upper plate (9b) and a bottom plate (12) for closing upper and lower ends thereof, defining a combustion chamber therein. Gas generator for
The combustion chamber is divided into two chambers, an upper combustion chamber (2) and a lower combustion chamber (3), by a partition member (4),
In the upper combustion chamber (2) and the lower combustion chamber (3), there are igniters (7, 8) operating independently of each other together with the gas generating agent (5) and the filter member (6) surrounding the gas generating agent (5). They are respectively charged arrangement,
Wherein the cylindrical body portion (11), respectively opening into the upper and lower combustion chambers (2,3), a plurality of gas discharge holes (11a) is formed for supplying gas into the airbag,
It is possible to operate the ignition device (7, 8) with a time difference, and at the initial stage of airbag deployment, one of the combustion chambers of the upper combustion chamber (2) and the lower combustion chamber (3) A gas generator characterized in that it can be deployed slowly with the gas generated by only the gas and then rapidly expanded by adding the gas generated in the other combustion chamber   The gas generator according to claim 1, wherein each ignition device (7, 8) is inserted and arranged in each of the upper and lower combustion chambers (2, 3) from the bottom plate (12) side.   The gas generator according to claim 1 or 2, wherein the ignition devices (7, 8) are arranged symmetrically with respect to a center line of the cylindrical body (11).   The ignition device (7) of the upper combustion chamber (2) is disposed on the same axis as the center line of the cylindrical body (11) and penetrating the lower combustion chamber (3). Or the gas generator of 2 The gas generator according to any one of claims 1 to 4, wherein a flange member having a cylindrical portion (30b) surrounding the gas discharge hole (11a) opened in the lower combustion chamber (3) is attached. In the gas generator for airbag deployment,
A covered cylindrical upper lid (9) comprising a short cylindrical portion (9a) and an upper plate (9b) closing one end thereof;
A bottomed cylindrical lower lid (10) composed of an outer tube portion (11) and a bottom plate (12) closing one end thereof;
A housing (1) formed by butt-joining these upper and lower lids (9, 10);
The partition member (4) is disposed inside the housing (1), and two combustion chambers (2, 3) are defined above and below in the cylindrical axis direction,
In each of the combustion chambers (2, 3), a gas generating agent (5), a cylindrical filter member (6) surrounding the gas generating agent (6), and an ignition device (7, 8) are arranged.
The bottom plate (12) of the lower lid (10) includes a short fixed inner cylinder (16) protruding into the lower combustion chamber (3), the lower combustion chamber (3), and the partition member (4). And a long fixed inner cylinder (15) projecting into the upper combustion chamber (2) through
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.
The outer cylinder portion (11) of the lower lid (10) has a plurality of gas discharge holes (11a) for supplying gas into the airbag, which open to the respective combustion chambers (2, 3). Forming ,
It is possible to operate the ignition device (7, 8) with a time difference, and at the initial stage of airbag deployment, one of the combustion chambers of the upper combustion chamber (2) and the lower combustion chamber (3) A gas generator characterized in that it can be deployed slowly with the gas generated by only the gas and then rapidly expanded by adding the gas generated in the other combustion chamber   The long fixed inner cylinder (15) is disposed at the center of the bottom plate (12) of the lower lid (10) and extends to the upper plate (9b) of the upper lid (9) and is butt joined to the upper lid. The gas generator according to claim 6.

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