JP4757375B2 - Gas generator for airbag - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air bag gas generator and an air bag apparatus using the same.
[0002]
[Prior art and problems to be solved by the invention]
Airbag systems installed in various vehicles, including automobiles, support passengers with airbags (bags) that are rapidly inflated by gas when the vehicle collides at high speed. The purpose is to prevent injuries and the like by crashing into hard parts such as the front glass and the like inside the vehicle. Such an air bag system is usually composed of a gas generator that is operated by a vehicle collision to release gas and an air bag that is inflated by introducing gas.
[0003]
As a gas generator used in such an airbag system, Japanese Patent Application Laid-Open No. 8-207696 discloses a gas generator that ignites a capsule of two kinds of gas generating agents with one igniter and generates gas in two stages. In U.S. Pat.No. 4,998,751 and U.S. Pat.No. 4,950,458, two combustion chambers are provided to regulate the operation function of the gas generator. Has been. In a gas generator having two combustion chambers, in order to reduce weight and size, a gas flow path from one combustion chamber to be burned later uses another combustion chamber that burns first. In the case of the gas generator of this form, the two combustion chambers are communicated with each other through the communication hole, and the communication hole is closed with a thin metal plate. In the case of such a gas generator, the metal sheet cannot be broken during the previous combustion, but it needs to be easily peeled off or broken during the subsequent combustion.
[0004]
In addition, depending on the type of gas generating agent, it is necessary to increase the pressure in the gas generating chamber at the time of the first combustion in order to improve the ignitability. In this case, the metal thin plate is used to increase the pressure in the combustion chamber. It is necessary to set so that it can withstand, and to be easily peeled off during subsequent combustion.
[0005]
The present invention secures safety and reliability in a gas generator provided with two combustion chambers, and also provides a gas generator for an air bag capable of stably and effectively expressing the feature that gas can be generated in two stages. An object is to provide a used airbag apparatus.
[0006]
[Means for Solving the Problems]
The present invention can be applied to any gas generator for an airbag having a structure having two combustion chambers and a communication hole communicating with the two combustion chambers, and other structures are particularly limited. It is not a thing.
[0007]
According to the present invention, a housing having a gas discharge port includes an ignition means that is activated by an impact, and a gas generation means that generates a combustion gas that is ignited and burned by the ignition means to inflate an airbag. A gas generator for an air bag comprising a first combustion chamber and a second combustion chamber each containing a gas generating means in a housing and having communication holes communicating with each other; Provided is a gas generator for an airbag in which communication holes between a first combustion chamber and a second combustion chamber are closed by a plurality of stacked metal thin plates with an adhesive interposed therebetween.
[0008]
In the present invention, the communication hole is preferably closed from the first combustion chamber wall surface side by a thin metal plate.
[0009]
The communication hole connecting the first combustion chamber and the second combustion chamber is affixed with a first metal thin plate on the communication hole with an adhesive (this adhesive becomes the “first adhesive layer”). A second sheet of metal is pasted onto the first sheet of metal with an adhesive (this adhesive becomes the “second adhesive layer”), and if necessary, the third and subsequent sheets of metal Is stuck through an adhesive layer (this adhesive layer becomes a “third adhesive layer” or the like) and closed. The first metal thin plate has the first pressure-sensitive adhesive layer on the entire surface or the surface excluding the portion in contact with the communication hole, and the second and subsequent metal thin plates have the second pressure-sensitive adhesive layer (or third, It is preferable to have a fourth adhesive layer).
[0010]
The thickness of the metal thin plate and the pressure-sensitive adhesive layer is appropriately determined so as to operate properly as a gas generator for an air bag according to the type and amount of the gas generating means, the size of the communication hole, etc. The total thickness of the plurality of metal thin plates (excluding the adhesive) can be preferably 10 to 200 μm, more preferably 20 to 100 μm, and the thickness of each metal thin plate is preferably 5 to 100 μm, more preferably Can be 10 to 50 μm, more preferably 25 to 55 μm. Moreover, the thickness after a 3rd adhesive layer can also be selected within the said range.
[0011]
When the pressure-sensitive adhesive layer is the first and second pressure-sensitive adhesive layers, the thickness of the first pressure-sensitive adhesive layer and the thickness of the second pressure-sensitive adhesive layer are each preferably 10 to 50 μm, more preferably 20 to 40 μm. it can.
[0012]
When the communication hole is closed with a plurality of thin metal plates via the first and second pressure-sensitive adhesive layers and the like in this way, the gas generating means in the first combustion chamber burns and the pressure rises, and the entire thin metal plate When a large pressure is applied, the total thickness of the plurality of thin metal plates is increased, so that it is prevented from bursting due to an increase in pressure. When the thickness of one metal thin plate is increased to about two, the metal thin plate will not burst against pressure, but the metal thin plate is in a non-planar state, for example, a curved shape, according to the shape of the portion where the communication hole is formed. In many cases, the force to return to the flat shape exceeds the adhesive strength of the adhesive and the metal thin plate may peel off, so use multiple metal thin plates as in the present invention. Therefore, it can be prevented from peeling off.
[0013]
Further, when the gas generating means in the second combustion chamber burns and the pressure rises, the adhesive force of the first pressure-sensitive adhesive layer is sufficiently smaller than the pressure, so that the two metal thin plates are easily peeled off.
[0014]
The gas generator for an air bag of the present invention is desirable because it can enhance the ignition performance by increasing the pressure of the first gas generation chamber, particularly when the gas generation means having low ignitability is arranged in the first combustion chamber. .
[0015]
Examples of gas generating means suitable for the gas generator for an air bag of the present invention include a gas generating agent containing, for example, a guanidine derivative and a basic metal nitrate, and a gas containing an additive acting as a binder and / or a slag forming agent. Examples include generators.
[0016]
The gas generator for an air bag of the present invention is housed in a module case together with an air bag (bag body) that is inflated by introducing a gas generated by the gas generator, thereby forming an air bag device. In this airbag device, the gas generator is operated in conjunction with the impact sensor detecting the impact, and the combustion gas is discharged from the gas discharge port of the housing. The combustion gas flows into the air bag, whereby the air bag breaks the module cover and inflates to form a cushion that absorbs an impact between a hard structure in the vehicle and the occupant.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, based on the embodiment shown in the drawings, the gas generator for an air bag of the present invention will be described.
[0018]
FIG. 1 is a longitudinal sectional view of a gas generator for an air bag according to the present invention, which is particularly suitable for being arranged on the driver's seat side.
[0019]
In this gas generator, a substantially cylindrical inner cylinder member 4 is disposed in a housing 3 formed by joining a diffuser shell 1 having a gas discharge port and a closure shell 2 that forms an internal housing space together with the diffuser shell 1. And the outside is used as the first combustion chamber 5a.
[0020]
Further, a stepped portion 6 is provided inside the inner cylindrical member 4, and a substantially flat circular partition wall 7 is arranged in the stepped portion 6, and the inner cylindrical member 4 is further divided into two chambers by the partition wall 7. The second combustion chamber 5b is formed on the diffuser shell 1 side (upper space side), and the ignition means accommodation chamber 8 is formed on the closure shell 2 side (lower space side).
[0021]
As a result, in this gas generator, the first combustion chamber 5 a and the second combustion chamber 5 b are provided concentrically within the housing 3 and are adjacent to each other in the radial direction of the housing 3. In the first and second combustion chambers 5a and 5b, gas generating agents 9a and 9b that burn by an ignition means that operates under impact and generate combustion gas are accommodated. Contains ignition means which is activated by impact.
[0022]
A communication hole 10 is provided in the inner cylinder member 4 that defines the first combustion chamber 5a and the second combustion chamber 5b, and the communication hole 10 is closed by a two-layer seal tape 11. Yes. This two-ply seal tape is a stainless steel (SUS304) tape having a thickness of 40 μm (the tensile strength of one stainless steel tape is 54 kg / mm ² ). The first adhesive layer and the second adhesive layer The thickness of each is 30 μm.
[0023]
The ignition means includes two electric ignition igniters 12a and 12b that are actuated by an actuation signal that is output when the sensor senses an impact, and each igniter includes one initiator collar 13 Are parallel to each other and have their heads protruding. By providing the two igniters 12a and 12b in one initiator collar 13 in this way, the two igniters are fixed to the initiator collar 13 to become a single member, and can be easily assembled to the gas generator. . In particular, in the gas generator shown in this figure, the initiator collar 13 provided with two igniters 12a and 12b is placed in the inner cylinder 4 by making the initiator collar 13 large enough to be inserted into the inner cylinder member 4. After the insertion, the two igniters can be easily and reliably fixed by crimping the lower end of the inner cylinder member 4 to fix the initiator collar 13.
[0024]
In this embodiment, a substantially cylindrical separation cylinder is provided so as to surround any one of the igniters 12b (hereinafter referred to as “second igniters”) in the space between the initiator collar 13 and the partition wall 7. 14 is arranged, a first transfer charge storage chamber 15a is defined on the outer side, a second transfer charge storage chamber 15b is defined on the inner side, and an igniter and an igniter are configured in each of the storage chambers. Contains explosives to be stored. As a result, the charge transfer agents 16a and 16b that constitute the ignition means together with the igniter are reliably divided for each of the igniters 12a and 12b.
[0025]
In the first transfer charge storage chamber 15a, when the transfer charge 16a accommodated therein burns, the seal tape 18 closing the transfer hole 17 formed in the inner cylinder member 4 is ruptured and the first combustion is performed. It communicates with the chamber 5a. Further, in the second transfer charge storage chamber 15b, when the transfer charge 16b therein burns, the seal tape 20 closing the transfer hole 19 formed in the partition wall 7 is ruptured and communicates with the second combustion chamber 5b. Therefore, when this gas generator is operated, the flame when the first igniter 12a is ignited (actuated) ignites and burns the transfer charge 16a in the storage chamber 15a, and the flame is the inner cylinder member. The 7-hole gas generating agent 9a accommodated in the first combustion chamber 5a positioned in the radial direction of the storage chamber 15a through the heat transfer holes 17 formed in 4 is ignited and burned.
[0026]
The second igniter 12b ignites and burns the second transfer charge 16b in the storage chamber 15b, and the flame passes through the transfer hole 19 provided in the axial direction of the storage chamber 15b. The single-hole gas generating agent 9b accommodated in the second combustion chamber 5b is ignited and burned. The combustion gas generated in the second combustion chamber 9 b flows into the first combustion chamber 5 a through the communication hole 10 provided on the diffuser shell 1 side of the inner cylinder member 4.
[0027]
In the gas generator shown in FIG. 1, the second igniter 12b and the first igniter 12a may be ignited at the same time in order to stabilize the operation performance, but the former 12b operates before the latter 12a. There is nothing. That is, the gas generating agent 9b accommodated in the second combustion chamber 5b burns simultaneously with or behind the gas generating agent 9a accommodated in the first combustion chamber 5a.
[0028]
In the gas generator shown in FIG. 1, the separation cylinder 14 arranged between the initiator collar and the partition wall is provided with a hole 21 corresponding to the outer shape of the separation cylinder 14 on the lower surface of the partition wall 7 and the upper surface of the initiator collar 13. , The upper end or the lower end of the separation cylinder 14 is inserted into each hole. By arranging the separation cylinder 14 in this way, the flame of the transfer charge generated in any one of the transfer charge combustion chambers does not directly burn the transfer charge in the other transfer charge storage chambers. The gas generating agent accommodated in the combustion chamber is ignited and burned by a flame in which different types of explosives are burned. That is, normally, when the transfer charge burns in the separation cylinder 14 (that is, in the second transfer charge storage chamber), the pressure of the gas generated by the combustion also causes the separation cylinder 14 to expand in the radial direction. Although the upper and lower ends of the separation cylinder 14 are surely supported by the peripheral walls of the holes into which the separation cylinders 14 are inserted, compared to the case where the separation cylinder is simply sandwiched between the partition wall and the initiator collar, It is possible to more reliably prevent leakage of the transfer gas combustion gas and flame.
[0029]
A common coolant filter 22 for purifying and cooling the combustion gas generated by the combustion of the gas generating agents 9a and 9b is disposed in the housing 3, and the inner peripheral surface on the diffuser shell 1 side is The short-pass prevention member 23 is used to prevent the combustion gas from passing between the end face of the coolant / filter 22 and the inner surface of the diffuser shell 1 ceiling. Outside the coolant / filter 22, an outer layer 24 is arranged to prevent the filter 22 from expanding due to passage of combustion gas. The outer layer 24 is formed using, for example, a laminated wire mesh body, or a porous cylindrical member having a plurality of through holes on the peripheral wall surface, or a belt-like restraining layer in which a belt-like member having a predetermined width is formed in an annular shape. You can also.
[0030]
Further, a gap 25 is formed outside the outer layer 24 so that the combustion gas can pass through the entire surface of the filter 22. The gas outlet 26 formed in the diffuser shell is closed with a seal tape 27 to prevent the outside air from entering. The seal tape 27 is ruptured when gas is released. The purpose of the seal tape 27 is to protect the gas generating agent from external moisture, and it does not affect the performance adjustment such as the combustion internal pressure at all.
[0031]
In the gas generator of the present embodiment, when the first igniter 12a disposed outside the separation cylinder 14 in the ignition means accommodating chamber 8 is activated, it is accommodated in the first transfer charge accommodating chamber 15b. The first transfer agent 16a is ignited and burned, and the flame passes through the transfer hole 17 of the inner cylinder member 4 and has a porous cylindrical first gas generating agent having seven holes accommodated in the first combustion chamber 5a. 9a is burned. At this time, the two-layered sealing tape 11 that closes the communication hole 10 is ruptured due to the improvement in strength due to the total thickness of the sealing tape and the relaxation of the repulsive force of the sealing tape itself due to the presence of the second adhesive layer. The pressure in the first firing chamber 5a can be increased to such an extent that the ignition and combustion of the gas generating agent 9a is performed smoothly without being peeled off or peeled off.
[0032]
Further, when the second igniter 12b surrounded by the separation cylinder 14 operates in the same or delayed manner as the first igniter 12a, the charge transfer agent 16b accommodated in the second transfer charge storage chamber 15b is ignited. Combustion, and the flame ignites and burns the single-hole cylindrical second gas generating agent 9b accommodated in the second combustion chamber 5b. At this time, the sealing tape 11 easily peels off due to the increase in the internal pressure of the second combustion chamber 5 b, and the second combustion chamber 5 b and the first combustion chamber 5 a are communicated with each other through the communication hole 10.
[0033]
In the gas generator of the present embodiment, the ignition timing of the two igniters 12a and 12b is adjusted, that is, the second igniter is operated after the first igniter is operated, or the first igniter and Depending on whether the second igniter is operated at the same time, the output configuration (operation performance) of the gas generator can be adjusted arbitrarily. In various situations such as the speed of the vehicle at the time of collision and the environmental temperature, the airbag described later When the apparatus is used, the airbag can be deployed to the maximum extent. In particular, in the gas generator shown in this figure, gas generating agents 9a and 9b having different shapes are used for the respective combustion chambers 5a and 5b, and the first combustion chamber 5a has a first gas generation having a porous cylindrical shape. The second gas generating agent 9b having a single-hole cylindrical shape is accommodated in the second combustion chamber 5b. Of course, the shape, composition, composition ratio, amount, and the like of the gas generating agent can be appropriately changed in order to obtain a desired output form.
[0034]
In the gas generator for an air bag of the present invention, the communication hole 10 is made of two stainless steel (SUS304) tapes having a thickness of 40 μm (the tensile strength of one stainless steel tape is 54 kg / mm ² ) and an adhesive (first And when the second pressure-sensitive adhesive layer is blocked by a thickness of 30 μm), it does not rupture or peel off to an internal pressure of about 30,000 kPa. Therefore, in the first combustion chamber 5a, the shape shown in FIG. 1 is composed of 20 to 60% by weight of nitroguanidine, 35 to 75% by weight of basic copper nitrate and 0.1 to 10% by weight of guar gum as the gas generating agent 9a. When this is used, ignition and combustion can be performed smoothly. The two-layer stainless steel tape peels off against the pressure from the second combustion chamber side.
[0035]
The gas generator for an air bag of the present invention can be applied to an air bag device including a gas generator, an impact sensor, a control unit, a module case, and an air bag.
[0036]
【The invention's effect】
According to the present invention, the ignition combustion of the gas generating means in one combustion chamber prevents the gas generating means in the other combustion chamber from being ignited and burned, so that malfunction is prevented and the safety of the gas generator is prevented. And can improve the reliability. Even when a gas generating means with low ignitability is used, the gas generating means can be ignited and burned smoothly.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of a gas generator of the present invention.
[Explanation of symbols]
3 Housing 5a First combustion chamber 5b Second combustion chamber 7 Partition wall 9a First gas generating agent 9b Second gas generating agent 12a First igniter 12b Second igniter 13 Initiator collar 22 Coolant filter

Claims (5)

In a housing (3) having a gas discharge port (26), an igniter (12a, 12b) that is activated by an impact, and a combustion gas that is ignited and burned by the igniter (12a, 12b) to inflate an airbag A gas generator for an air bag containing and containing a gas generating agent (9a, 9b) that generates
A gas generating agent (9a, 9b) is accommodated in the housing (3), and a first combustion chamber (5a) and a second combustion chamber (5b) having communication holes (10) communicating directly with each other are provided. It is provided concentrically and adjacent to the radial direction,
A first igniter (12a) for igniting the gas generating agent (9a) stored in the first combustion chamber (5a), and a gas generating agent stored in the second combustion chamber (5b) ( A second igniter (12b) is provided for igniting 9b),
The communication hole (10) between the first combustion chamber (5a) and the second combustion chamber (5b) is formed by attaching a plurality of stacked metal thin plates (11) in a curved shape via an adhesive. Is blocked,
A plurality of stacked metal thin plates (11) via the adhesive is a two-layer stainless steel tape via an adhesive, and the thickness of one stainless steel tape is in the range of 25 to 50 μm,
When a plurality of stacked thin metal plates (11) via an adhesive is ignited and combusted by the first igniter (12a) and the gas generating agent (9a) in the first combustion chamber (5a) is ignited and burned The gas generator (9b) in the second combustion chamber (5b) is ignited and burned off when the second igniter (12b) is activated and does not rupture or peel off And
When the first igniter (12a) is activated first and the second igniter (12b) is activated later, the first igniter (12a) and the second igniter (12b) are activated simultaneously. And a gas generator for an air bag which can be implemented when only the first igniter (12a) is operated. Communicating hole peripheral portion and the first piece gas generator for an air bag according to claim 1, wherein the thickness of the first adhesive layer is a 10~50μm of the metal sheet is provided on the surface contacting the. The gas generator for an air bag according to claim 1 or 2 , wherein the thickness of the second pressure-sensitive adhesive layer provided on the surface where the first metal thin plate and the second metal thin plate are in contact is 10 to 50 µm. The gas generator for an air bag according to any one of claims 1 to 3 , wherein the communication hole is closed by a metal thin plate from the wall surface side of the first combustion chamber. A gas generator for an air bag, an impact sensor that senses an impact and activates the gas generator, an air bag that expands by introducing gas generated by the gas generator, and a module case that houses the air bag An air bag apparatus, wherein the gas generator for an air bag is the gas generator for an air bag according to any one of claims 1 to 4 .

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