JP4493790B2 - Gas generator with automatic ignition function - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas generator for an air bag in which a gas generating agent has an automatic ignition function and does not require the use of a material having an automatic ignition function.
[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 generally composed of a gas generator that is activated by a vehicle collision to burn a gas generating agent and release gas, and an air bag that expands by introducing gas. In this gas generator, the combustion of the gas generating agent is performed by operating the system based on the command of the sensor that detects the impact at the time of collision, and the combustion of the direct or enhancer (transfer agent) is activated by the operation of the system. It is made through
[0003]
As described above, the gas generator is activated by the collision of the vehicle. Therefore, the gas generator does not operate when an emergency such as a vehicle fire not caused by the collision of the vehicle occurs. Therefore, when the ambient temperature of the gas generator rises to a temperature equal to or higher than the ignition point of the gas generating agent due to a vehicle fire or the like, the gas generating agent may ignite and burn (explode). At this time, when the heat resistance of the outer shell container of the gas generator is low and the ignition point of the gas generating agent is high, the strength decreases due to deformation of the outer shell container due to an increase in the ambient temperature. When an explosion occurs, the outer shell container may be destroyed and scattered by the explosion pressure, which may injure the human body.
[0004]
In order to prevent the occurrence of such a situation and ensure safety, conventionally, the gas generator is operated without any mechanical or electrical ignition means involved in the transfer charge as the ambient temperature rises. A material (automatic ignition material) having an automatic ignition function that automatically ignites without being arranged is arranged. For example, nitrocellulose (ignition point 170 ° C) has been conventionally used as an auto-ignition material. In the case of a vehicle fire, the auto-ignition is performed at a low temperature before the strength of the outer shell container of the gas generator is reduced. The charge is burned and the gas generating agent is burned at the same time.
[0005]
However, since nitrocellulose has poor heat resistance, it degrades and degrades over a long period of time (the number of years the vehicle has been used, usually several to 10 to several years), and there is a possibility that the automatic ignition function may not be exhibited. Moreover, when using an auto-ignition material, the accompanying increase in the weight of the gas generator and the increase in manufacturing cost also occur, so there is room for improvement from this point.
[0006]
The present invention is a gas generator for an air bag that can maintain an automatic ignition function even after a long period of time and ensure safety in an emergency such as a vehicle fire, and at the same time, can reduce the weight of the gas generator and reduce manufacturing costs. The purpose is to provide.
[0007]
[Means for Solving the Problems]
The present invention solves the above-mentioned problems by providing an automatic ignition function to the gas generating agent itself instead of the conventional method of arranging an automatic ignition material such as nitrocellulose. That is, the present invention provides a gas generator for an air bag using a gas generating agent having an automatic ignition function that does not involve mechanical or electrical ignition means.
[0008]
The “automatic ignition function that does not involve mechanical or electrical ignition means” in the present invention is a function that spontaneously ignites when the ambient temperature rises. Here, the “ambient temperature at which ignition occurs (that is, corresponding to the ignition temperature of the gas generating agent)” is a temperature that can solve the above-described problem in relation to a gas generator for an air bag, particularly an outer shell container (housing). Specifically, the temperature is such that the strength of the outer shell container of the gas generator for an air bag does not decrease. In the following, “automatic ignition function” means “automatic ignition function not involving mechanical or electrical ignition means”.
[0009]
The “airbag gas generator” in the present invention is a gas generator for an air bag in the driver's seat of various vehicles, as long as the gas supply source is of a pyro type (pyrotechnic) with only a gas generating agent. In addition to gas generators for seat airbags and gas generators for side airbags, gas generators for inflatable curtains, generators for knee bolsters, gas generators for inflatable seat belts, gas generators for tubular systems, pretensioners It can also be applied to industrial gas generators.
[0010]
The gas generating agent used in the present invention has a weight reduction rate of 2.0% by weight or less when held at 110 ° C. for 400 hours, preferably 1.0% by weight or less, more preferably 0.5% by weight or less, and It is desirable that the automatic ignition function is maintained even after holding under the above conditions.
[0011]
The gas generating agent used in the present invention preferably has an ignition point of 200 ° C. or lower, more preferably 200 to 175 ° C.
[0012]
The gas generating agent used in the present invention is preferably one containing a guanidine derivative and a basic metal nitrate, or one containing a guanidine derivative, a basic metal nitrate and an additive.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
First, an embodiment of the present invention will be described with reference to FIG. 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.
[0014]
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. And the outside is used as the first combustion chamber 5a.
[0015]
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 this partition wall. A second combustion chamber 5b is formed on the diffuser shell side, and an ignition means accommodation chamber 8 is formed on the closure shell side.
[0016]
As a result, in this gas generator, the first combustion chamber 5a and the second combustion chamber 5b are provided concentrically in the housing 3 and are adjacent to each other in the radial direction of the housing. In the first and second combustion chambers, gas generating agents 9a and 9b that generate combustion gas are burned by the ignition means that operates under impact, and the ignition means storage chamber 8 receives shock. Actuating ignition means is housed.
[0017]
A through hole 10 is provided in the inner cylindrical member 4 that defines the first combustion chamber 5 a and the second combustion chamber 5 b, and the through hole is closed by a seal tape 11. However, since the seal tape 11 bursts when the gas generating agent burns, both the combustion chambers can communicate with each other through the through hole 10. The material and thickness of the seal tape 11 are adjusted so that the seal tape 11 is not broken by the combustion of the gas generating agent 9a in the first combustion chamber 5a but is torn when the gas generating agent 9b in the second combustion chamber 5b is burned. There is a need. In this embodiment, a stainless steel seal tape having a thickness of 40 μm is used. Further, the through hole 10 has an opening area larger than that of the gas discharge port 26 and does not have a function of controlling the internal pressure in the combustion chamber 5b.
[0018]
In the present embodiment, the ignition means accommodating chamber 8 is defined by a space between the initiator collar 13 and the partition wall 7, and any one igniter 12b (hereinafter referred to as "second igniter"). A substantially cylindrical separation tube 14 is disposed so as to surround the first transfer charge storage chamber 15a on the outer side, the second transfer charge storage chamber 15b on the inner side, and in each storage chamber, The igniters 12a and 12b and the charge transfer agents 16a and 16b that constitute the ignition means together with the igniters are accommodated. In this embodiment, there is no remaining space in the ignition means accommodation chamber 8 except for the respective charge transfer agent accommodation chambers. As a result, the ignition means storage chamber 8 is divided into two parts, a first transfer charge storage room 15a and a second transfer charge storage room 15b, and the transfer charge 16a and 16b constituting the ignition means together with the igniter are Thus, the igniters 12a and 12b are surely divided.
[0019]
  In the first charge transfer chamber 15a, when the charge transfer 16a accommodated therein burns, the seal tape 18 that closes the transfer hole 17 formed in the inner cylinder member 4 is ruptured, and the first combustion chamber. The porous gas generant 9a is ignited and burned in communication with 5a. When the transfer charge 16b accommodated in the second transfer charge storage chamber 15b burns, the seal tape 20 that closes the transfer transfer hole 19 formed in the partition wall 7 is ruptured, and the second combustion chamber 5b and The single-hole gas generating agent 9b is ignited and burned in communication. This second combustion chamber5bThe combustion gas generated inside flows into the first combustion chamber 5a through the through-hole 10 provided on the diffuser shell 1 side of the inner cylinder member 4. Therefore, when this gas generator is operated, the flame when the first igniter 12a is ignited ignites and burns the charge transfer agent 16a in the storage chamber 15a, and the flame is applied to the inner cylinder member 4. The seven-hole gas generating agent 9a housed in the first combustion chamber 5a positioned in the radial direction of the housing chamber 15a through the formed heat transfer holes 17 is ignited and burned.
[0020]
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. When the gas generating agent 9a in the first combustion chamber 5a burns before the second gas generating agent 9b, the seal tape 11 is not broken by the combustion of the first gas generating agent 9a, and the second gas generation It is broken only by the combustion of the agent 9b.
[0021]
In the gas generator shown in FIG. 1, the separation cylinder 14 disposed between the initiator collar 13 and the partition wall 7 has a hole 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. And the upper end or the lower end of the separation cylinder 14 is fitted into each hole. By arranging the separation cylinder 14 in this way, the flame of the transfer charge generated in 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 separation cylinder 14 is arranged, the upper and lower end portions of the separation cylinder 14 are surely supported by the peripheral walls of the holes into which the separation cylinder 14 is inserted, and the separation cylinder 14 is simply attached to the partition wall 7 and the initiator. Compared with the case where it is sandwiched between the collar 13, it is possible to more reliably prevent leakage of the combustion gas / flame of the charge transfer agent.
[0022]
The ignition means includes two electric ignition igniters (12a, 12b) that are activated by an activation signal that is output based on sensing of an impact by the sensor. The initiator collars 13 are provided with their heads protruding in parallel with each other. By providing two igniters (12a, 12b) in one initiator collar 13 in this way, the two igniters are fixed to the initiator collar 13 and become a single member, and can be easily assembled to the gas generator. It becomes. In particular, in the gas generator shown in this figure, the initiator collar 13 provided with two igniters (12a, 12b) is placed in the inner cylinder member 4 by making the initiator collar 13 into a size that can be inserted into the inner cylinder member 4. After the insertion, the igniter can be easily and reliably fixed by crimping the lower end of the inner cylinder member 4 to fix the initiator collar 13. Further, when the two igniters (12a, 12b) are arranged on the initiator collar 13, the direction of each igniter can be easily regulated.
[0023]
Further, a common coolant filter 22 for purifying and cooling the combustion gas generated by the combustion of the gas generating agent (9a, 9b) is disposed in the housing 3, and the inner side of the diffuser shell 1 side thereof is disposed. The peripheral surface is covered with a short path preventing member 23 so that the combustion gas does not pass between the end surface of the coolant / filter 22 and the inner surface of the diffuser shell 1 ceiling.
[0024]
An outer layer 24 for preventing the coolant / filter 22 from expanding due to the passage of combustion gas is disposed outside the coolant / filter 22. The outer layer 24 is formed by using, for example, a laminated wire mesh body, or by using 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.
[0025]
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 discharge port 26 formed in the diffuser shell 1 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.
[0026]
In this embodiment, as the gas generating agents 9a and 9b, in order to provide an automatic ignition function, (a) a guanidine derivative and (b) a basic metal nitrate-containing substance or (a) a guanidine derivative, (b) a basic substance The one containing metal nitrate and (c) additive is used. In this embodiment, since the seal tape 11 is ruptured only by the combustion of the gas generating agent 9b, the gas generating agent 9b needs to be a gas generating agent having an automatic ignition function as described above. The generating agent 9a may or may not have an automatic ignition function.
[0027]
Examples of the component (a) guanidine derivative include one or more selected from guanidine, mono-, di- or triaminoguanidine nitrate, guanidine nitrate, guanidine carbonate, nitroguanidine (NQ), dicyandiamide (DCDA), and nitroaminoguanidine nitrate. Of these, nitroguanidine and dicyandiamide are preferred.
[0028]
The basic metal nitrate as component (b) is a series of compounds generally represented by the following formula. Further, there may be a compound further containing water of hydration. In the formula, M is a metal, x 'is the number of metals, and y and y' are NO._ThreeThe number of ions, z 'is the number of OH ions, and n is M (NO_Three)_yM (OH) for the part_zThe ratio of the parts is shown.
[0029]
M (NO_Three)_y・ NM (OH)_zOr M_{x '}(NO_Three)_{y '}(OH)_{z '}
Examples of those corresponding to the above formula include Cu, cobalt, zinc, manganese, iron, molybdenum, bismuth, cerium as the metal M, Cu₂(NO_Three) (OH)_Three, Cu_Three(NO_Three) (OH)_Five・ 2H₂O, Co₂(NO_Three) (OH)_Three, Zn₂(NO_Three) (OH)_Three, Mn (NO_Three) (OH)₂, Fe_Four(NO_Three) (OH)₁₁・ 2H₂O, Bi (NO_Three) (OH)₂, Ce (NO_Three)_Three(OH) ・ 3H₂O is mentioned.
[0030]
As the basic metal nitrate of component (b), basic copper nitrate (BCN), basic cobalt nitrate, basic zinc nitrate, basic manganese nitrate, basic iron nitrate, basic molybdenum nitrate, basic bismuth nitrate and 1 or more types chosen from basic cerium nitrate are mentioned, Among these, basic copper nitrate is preferable.
[0031]
When the gas generating agent contains the components (a) and (b), the content of the component (a) is preferably 5 to 60% by weight, and more preferably 15 to 55% by weight. The content of the component (b) is preferably 40 to 95% by weight, and more preferably 45 to 85% by weight.
[0032]
A preferable embodiment in which the gas generating agent contains components (a) and (b) includes those containing (a) nitroguanidine and (b) basic copper nitrate. The content in this case is preferably (a) 30 to 70% by weight of nitroguanidine and (b) 30 to 70% by weight of basic copper nitrate.
[0033]
As an additive of the component (c), carboxymethyl cellulose (CMC), carboxymethyl cellulose sodium salt (CMCNa), carboxymethyl cellulose potassium salt, carboxymethyl cellulose ammonium salt, cellulose acetate, cellulose acetate butyrate (CAB), methyl cellulose (MC), Ethyl cellulose (EC), hydroxyethyl cellulose (HEC), ethyl hydroxyethyl cellulose (EHEC), hydroxypropyl cellulose (HPC), carboxymethyl ethyl cellulose (CMEC), microcrystalline cellulose, polyacrylamide, polyacrylamide amination, polyacryl hydrazide, Acrylamide / acrylic acid metal salt copolymer, polyacrylamide / polyacrylic acid ester compound Copolymer, polyvinyl alcohol, acrylic rubber, guar gum, starch, silicone, molybdenum disulfide, acid clay, talc, bentonite, diatomaceous earth, kaolin, calcium stearate, silica, alumina, sodium silicate, silicon nitride, silicon carbide, hydro One or more selected from talcite, mica, metal oxide, metal hydroxide, metal carbonate, basic metal carbonate and molybdate can be mentioned.
[0034]
Examples of the metal oxide of component (c) include one or more selected from copper oxide, iron oxide, zinc oxide, cobalt oxide, manganese oxide, molybdenum oxide, nickel oxide, and bismuth oxide. , One or more selected from cobalt hydroxide and aluminum hydroxide, and as the metal carbonate and basic metal carbonate, calcium carbonate, cobalt carbonate, basic zinc carbonate, basic copper carbonate, basic cobalt carbonate 1 type or more chosen from basic iron carbonate, basic bismuth carbonate, and basic magnesium carbonate is mentioned, As a molybdate, one or more sorts chosen from cobalt molybdate and ammonium molybdate are mentioned. These compounds of component (c) can function as a slag forming agent and / or a binder.
[0035]
In order to enhance the ignitability of the gas generating agent, carboxymethyl cellulose sodium salt and potassium salt are preferable, and among these, sodium salt is more preferable.
[0036]
As a preferred embodiment when the gas generating agent contains components (a), (b) and (c), (a) nitroguanidine, (b) basic copper nitrate and (c) carboxymethylcellulose What contains a sodium salt is mentioned. The content in this case is preferably (a) nitroguanidine 15 to 55% by weight, (b) basic copper nitrate 45 to 70% by weight, and (c) carboxymethylcellulose sodium salt 0.1 to 15% by weight.
[0037]
Other preferred embodiments when the gas generating agent contains components (a), (b) and (c) include (a) nitroguanidine, (b) basic copper nitrate and (c) guar gum. The thing containing is mentioned. The content in this case is preferably (a) 20 to 60% by weight of nitroguanidine, (b) 35 to 75% by weight of basic copper nitrate and (c) 0.1 to 10% by weight of guar gum.
[0038]
The gas generating agent can be molded into a desired shape, and can be formed into a single-hole cylindrical shape, a porous cylindrical shape, or a pellet-shaped molded body. These molded products are prepared by adding water or an organic solvent to the gas generating agent, mixing and extruding (single-hole cylindrical or porous cylindrical molded body) or compression molding using a tableting machine (pellet). Shaped molded body).
[0039]
In the normal operation of the gas generator according to the present embodiment, the explosives (enhancer agents) 16a and 16b and the gas generating agents 9a and 9b are burned to generate gas as follows.
[0040]
The gas generator of the present embodiment was accommodated in the first explosive charge accommodating chamber 15a when the first igniter 12a disposed in the ignition means accommodating chamber 8 and outside the separation cylinder 14 was activated. 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.
[0041]
Further, when the second igniter 12b surrounded by the separation cylinder 14 is operated in the same or delayed manner as the first igniter 12a, the transfer charge 16b accommodated in the second transfer charge accommodating 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.
[0042]
As a result, the ignition timing of the two igniters (12a, 12b) is adjusted, that is, the second igniter is operated after the first igniter is operated, or the first igniter and the second igniter are operated. The output form (operation performance) of the gas generator can be adjusted arbitrarily depending on whether the two are operated at the same time. In various situations such as the vehicle speed and environmental temperature at the time of collision, It is possible to optimize the deployment of the air bag at the maximum.
[0043]
In particular, in the gas generator shown in this figure, gas generating agents (9a, 9b) having different shapes are used for the respective combustion chambers (5a, 5b), and the first combustion chamber 5a has a porous cylindrical second shape. One gas generating agent 9a is accommodated in the second combustion chamber 5b and a single-hole cylindrical second gas generating agent 9b is accommodated therein. Further, the amount of the gas generating agent accommodated in each combustion chamber (5a, 5b) is also different, and 35 g in the first combustion chamber 5a and 6 g in the second combustion chamber 5b (9a, 5b). 9b) is accommodated respectively. As a result, in this gas generator, it is possible to adjust the output form more accurately.
[0044]
Moreover, the gas generator of this embodiment ensures safety by burning the transfer agents (enhancer agents) 16a and 16b and the gas generating agents 9a and 9b in the following manner in an emergency such as a vehicle fire.
[0045]
When the ambient temperature of the gas generator rises due to a vehicle fire or the like, when the ambient temperature reaches the ignition point (for example, about 200 ° C.) of the gas generant 9b, the gas generant 9b is ignited and burned, and the seal is accordingly produced. The tapes 11 and 20 are ruptured to burn the gas generating agent 9a and the transfer agent 16b, and further, the seal tape 18 is ruptured and burns the transfer agent 16a as the gas generating agent 9a is burned. This is a case where only the gas generating agent 9b has an automatic ignition function, and when the gas generating agent 9a also has an automatic ignition function, the gas generating agents 9a and 9b are both automatically ignited, The transfer charge 16a, 16b is burned. Therefore, even when a material having a low melting point (about 660 ° C.) such as aluminum is used as the housing material, the gas generating agent and the transfer agent are burned before the strength of the housing is reduced. Since the ignition point of the gas generating agent is finally reached after the decrease of the gas, the housing itself is prevented from bursting and scattering due to the combustion of the gas generating agent.
[0046]
Next, another embodiment of the present invention will be described with reference to FIG. FIG. 2 is a longitudinal sectional view of the gas generator for an air bag of the present invention, and has a structure particularly suitable for being arranged on the driver's seat side. In the present embodiment, the combustion chamber is a single gas generator.
[0047]
In this gas generator, a substantially cylindrical inner cylinder member 113 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. The outside is a combustion chamber 122 and the inside is an ignition means accommodation chamber 155. As a result, in this gas generator, the combustion chamber 122 and the ignition means accommodation chamber 155 are provided concentrically within the housing 3 and are adjacent to each other in the radial direction of the housing. In this combustion chamber, a gas generating agent 106 that burns and generates combustion gas is accommodated by the ignition means that operates under impact, and in the ignition means accommodation chamber 155, ignition means that operates by impact is accommodated. Yes. The igniter 104 is installed in the ignition means accommodation chamber 155 via the initiator collar 114, the transfer agent 105 is accommodated in the transfer means accommodation chamber 123, and the remaining space 160 is in the ignition means accommodation chamber 155. Existing. In FIG. 2, 107 is a coolant filter, 109 is a gap, 111 is a gas discharge hole, 125 is a seal tape, 126 is a communication hole, and 150 is a short path preventing member.
[0048]
In the present embodiment, as the gas generating agent 106, a gas generating agent having an automatic ignition function as described above is used. Accordingly, in an emergency such as a vehicle fire, the gas generating agent 106 is automatically ignited by an increase in the ambient temperature. Since the combustion temperature of the gas generating agent is as high as about 2000 ° C., the enhancer agent and ignition agent are ignited and burned with a delay due to the combustion heat.
[0049]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these.
(1) Weight reduction rate
40 g of a gas generating agent (however, only fuel) was placed in an aluminum container, the total weight was measured, and (total weight-aluminum container weight) was taken as the sample weight before the test. The aluminum container containing the sample was placed in a SUS thick-walled container (internal volume 118.8 ml), capped, and then placed in a thermostatic chamber at 110 ° C. At this time, a rubber packing and a clamp were used so that the container was sealed. After a lapse of a predetermined time, the SUS thick container was taken out from the thermostatic bath, the lid was opened after the container returned to room temperature, and the aluminum container was taken out from the inside. The total weight of each aluminum container was measured, and (total weight-aluminum container weight) was taken as the sample weight after the test. And the heat resistance was evaluated by comparing the weight change before and after the test to determine the weight reduction rate. The weight reduction rate was obtained from [(gas generating agent weight before test−gas generating agent weight after test) / gas generating agent weight before test] × 100.
Example 1
A gas generating agent having a composition of nitroguanidine / basic copper nitrate / guam gum = 44.2 / 52.8 / 3.0 (% by weight) was produced, and the ignition temperature and the weight reduction rate were measured. The ignition temperature was measured with a Krupp ignition point measuring device and displayed as the ignition point for 60 seconds. As a result, the ignition temperature was 193 ° C. for the pulverized gas generant (pulverizing agent), 201 ° C. for the gas generant (extensive agent) in the stretched state, and the weight reduction rate was 110 ° C. for 214 hours. The time point was 0.27% and the time point after 408 hours at 110 ° C. was 0.45%.
[0050]
As is clear from this result, since the gas generating agent used in the gas generator of the present invention has a low ignition temperature, it is clear that in the case of a vehicle fire, it automatically ignites before the housing deteriorates due to heat. Furthermore, as is clear from the small weight loss rate, the heat resistance does not decrease even after a long period of time, so the automatic ignition function is not impaired.
[0051]
【The invention's effect】
In the gas generator for an air bag of the present invention, the gas generating agent has an automatic ignition function, and the function is not impaired for a long period of time. Therefore, safety and reliability can be improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an embodiment of a gas generator for an air bag according to the present invention.
FIG. 2 is a longitudinal sectional view of another embodiment of the gas generator for an air bag of the present invention.

Claims (1)

A substantially cylindrical inner cylinder in a housing (3) formed by joining a diffuser shell (1) having a gas discharge port (26) and a closure shell (2) that forms an internal housing space together with the diffuser shell (1) The member (4) is arranged, the outside is the first combustion chamber (5a),
The inner cylinder member (4) is divided into two chambers by the partition wall (7), so that the second combustion chamber (5b) is housed on the diffuser shell (1) side and the ignition means is housed on the closure shell (2) side. Chamber (8) is formed,
In the ignition means accommodation chamber (8), a first igniter (12a) and a second igniter (12b) that are activated by an impact are accommodated,
In the first combustion chamber (5a), the first gas generating agent (9a) that burns by the first igniter (12a) that operates under impact and generates combustion gas is housed.
The second combustion chamber (5b) contains a second gas generating agent (9b) that is burned by a second igniter (12b) that has been operated by impact and generates combustion gas.
At least the second gas generant (9b) in the second combustion chamber (5b)
(A) 5 to 60% by weight of fuel and (b) 40 to 95% by weight of oxidant,
(A) The component fuel is at least one guanidine derivative selected from guanidine, mono-, di- or triaminoguanidine nitrate, guanidine nitrate, guanidine carbonate, nitroguanidine (NQ), dicyandiamide (DCDA) and nitroaminoguanidine nitrate. Yes, automatic ignition function that spontaneously ignites without the second igniter (12b) operating when the oxidizing agent of component (b) is basic copper nitrate and the ambient temperature of the gas generator rises due to a vehicle fire A gas generator.

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