JP2001354106A - Gas generator and usage thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a conventional problem of complicating a structure when diversifying generating pressure in a gas generator using combustible gases. SOLUTION: This gas generator 1 is provided with first and second pressure chambers 11 and 12 blocked up by cleavable pressure diaphragms 31 and 32 and a third pressure chamber 13 formed between both pressure diaphragms 31 and 32 of the first and second pressure chambers 11 and 12, and is constituted such that the combustible gases different in a combustion speed are pressurized and filled in the first and second pressure chambers 11 and 12, and ignition means 41 and 42 are arranged, and the third pressure chamber 13 is provided with a gas blowoff port 3 and a cleavable pressure diaphragm 33 for blocking up the gas blowoff port 3. The generating pressure is changed by selecting the operating timing and a time difference of the ignition means 41 and 42, and the composition of the gas mixedly burnt in the third pressure chamber 13 can be changed, and a degree of freedom of control of a gas blowoff speed is enhanced.

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 as a gas source for inflating and deploying an airbag in an airbag system for protecting an occupant in the event of an automobile collision, and a method of using the same. .

[0002]

2. Description of the Related Art Conventionally, a gas generator using a solid gas generating agent has been employed in an airbag system of an automobile. In recent years, a gas generator using a flammable gas has been proposed. As a gas generator using a combustible gas, for example, a pressure vessel is closed with a pressure partition which can be opened at a predetermined pressure, and this pressure vessel is filled with a mixed gas containing a combustible gas and an inert gas under pressure. In addition, there is one provided with an electric ignition means for the mixed gas.

[0003] In the above gas generator, when a signal from a sensor that detects a collision of a vehicle is input, the mixed gas is ignited by an ignition means, and the combustible gas in the mixed gas is burned. The pressure ruptures the pressure bulkhead and releases gas instantaneously into the airbag. Compared to a gas generator using a solid gas generating agent, such a gas generator using a combustible gas has the advantages of improving layout flexibility, simplifying a manufacturing process, reducing costs, and the like. There is.

[0004]

By the way, the research and development of the airbag system for automobiles are further advanced in order to further improve the shock absorbing ability for the occupant. Accordingly, it is considered to change the gas release speed, that is, the degree of inflation of the airbag. In this case, the gas generator may be an aggregate of a plurality of sub-generators, or a plurality of igniters provided for one gas generator, and the operation timing of each sub-generator or igniter It is conceivable to control the gas release rate by changing the pressure.

[0005] However, it is clear that the structure of the gas generator provided with a plurality of generators and igniters is complicated, and if the range of selection of the gas discharge rate is widened, more gas generators are required. Since a gas generator and an igniter are required, the advantages of the gas generator using the flammable gas, that is, the improvement in the degree of freedom in layout, the simplification of the manufacturing process, the reduction in cost, and the like are impaired. For this reason, the conventional gas generator using a flammable gas has a problem that it is difficult to achieve free control of the gas release rate without impairing its advantages. The task was to solve the points.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems. In a gas generator using a flammable gas, the degree of freedom in layout, the simplification of the manufacturing process, and the cost reduction are reduced. It is an object of the present invention to provide a gas generator and a method of using the same, which can realize the above-described method and can increase the degree of freedom in controlling the gas release rate.

[0007]

According to a first aspect of the present invention, there is provided a gas generator comprising a first pressure chamber closed by a pressure partition cleaving at a predetermined pressure, and a second pressure chamber closed by a similar pressure partition. And a third pressure chamber formed between the two pressure partitions of the first and second pressure chambers. The first and second pressure chambers are pressurized and filled with a flammable gas having a different combustion rate. 3. A means for igniting a neutral gas, wherein the third pressure chamber is provided with a gas discharge port for communicating between the inside and outside of the chamber and a pressure partition for closing the gas discharge port and cleaving at a predetermined pressure. Wherein the flammable gas is a gas containing a gas selected from hydrogen and hydrocarbons and a gas containing oxygen, and the composition of the flammable gas to be charged under pressure into the first and second pressure chambers is different. As the third, the first pressure chamber contains hydrogen and oxygen. The combustible gas with pressure filled,
The second pressure chamber is filled with a flammable gas containing hydrocarbons and oxygen under pressure. According to a fourth aspect of the present invention, the third pressure chamber has a third pressure with respect to the opening pressure of the pressure partition closing the first and second pressure chambers. According to a fifth aspect of the present invention, the first and second pressure chambers are arranged coaxially in a state where the pressure partitions face each other. Forming a third pressure chamber between the two pressure partitions of the first and second pressure chambers, wherein the pressure partitions closing the first and second pressure chambers are in contact with each other when expanded and deformed by pressure. The arrangement is arranged, and the above arrangement is used as means for solving the conventional problem.

According to a sixth aspect of the present invention, there is provided a method of using the gas generator, wherein the gas generator according to any one of the first to fifth aspects is used, and both ignitions are performed in the first and second pressure chambers. The gas generator is operated by selecting the operation timing of the means from simultaneous and non-simultaneous. According to claim 7, the operation timing of both ignition means in the first and second pressure chambers is non-simultaneous, and The gas generator is operated by selecting the time difference, and the above-mentioned structure is used as means for solving the conventional problem.

[0009]

In the gas generator according to the first aspect of the present invention, when the flammable gas is ignited by the igniting means in the first and second pressure chambers, each pressure partition is generated by the pressure generated by the combustion. To release the gas into the third pressure chamber, and further cleave the pressure partition at the gas discharge port at that pressure to release the gas to the outside. Here, in the gas generator, the first and second pressure chambers are filled with flammable gas having different combustion speeds under pressure, so that both the ignition means are operated simultaneously and non-simultaneously. The generated pressure (gas release speed) changes depending on the case.

That is, since the pressure partitions of the first and second pressure chambers rupture at a pressure lower than the maximum pressure generated in each pressure chamber, when the pressure partitions rupture, the pressure of the first and second pressure chambers is reduced. The gas released into the third pressure chamber contains each unburned component, and both gases are mixed in the third pressure chamber. Therefore, when both ignition means are operated at the same time, the pressure partitions of the first and second pressure chambers are broken,
While the pressure in the third pressure chamber rises sharply, the two gases mix and burn, and the pressure breaks the pressure partition at the gas discharge port. Thereby, the generated pressure of the gas generator rises to near the maximum generated pressure in a short time.

When the ignition means of the first (or second) pressure chamber filled with a flammable gas having a high combustion rate under pressure is operated first, the rupture of the pressure partition of the first pressure chamber is followed by the opening of the first pressure chamber. As a result, the pressure partition of the second pressure chamber is split, and both gases are mixed and burned in the third pressure chamber, so that the pressure of the third pressure chamber increases and the pressure partition of the gas discharge port is split. In this case, the combustion of the combustible gas with the fast burning speed is performed first, and the unburned component is reduced. Therefore, the mixing ratio of the gas in the third pressure chamber is higher for the combustible gas with the slow burning speed. There will be many. Therefore, the generated pressure of the gas generator increases stepwise. In the case where the time difference between the operations of the two ignition means is extremely short, when the pressure partition of the first pressure chamber ruptures, the second
Since the pressure in the pressure chamber is rising, the pressure partition of the gas discharge port may be split before the pressure partition of the second pressure chamber, and then the pressure partition of the second pressure chamber may be split. Also in this case, the pressure generated by the gas generator increases stepwise.

On the other hand, when the ignition means of the second (or first) pressure chamber filled with a combustible gas having a low combustion rate under pressure is activated first, the rupture of the pressure partition of the second pressure chamber is followed by As a result, the pressure partition of the first pressure chamber is split, and both gases are mixed and burned in the third pressure chamber, so that the pressure of the third pressure chamber increases and the pressure partition of the gas discharge port is split. In this case, the combustion of the combustible gas having the slow burning speed is performed first, and the unburned component is reduced. Therefore, the mixing ratio of the gas in the third pressure chamber is higher for the combustible gas having the faster burning speed. There will be many. Therefore, the generated pressure of the gas generator gradually increases in the initial stage, and then rapidly increases. If the time difference between the operations of the two ignition means is extremely short, the pressure in the first pressure chamber is increased when the pressure partition of the second pressure chamber ruptures. Also, the pressure partition of the gas discharge port may be split first, and then the pressure partition of the first pressure chamber may be split. Also in this case, the pressure generated by the gas generator gradually increases in the initial stage, and then rapidly increases.

Further, in the gas generator, the breaking pressure of the pressure partition in the first and second pressure chambers is set, and the burning rate of the combustible gas to be filled in the first and second pressure chambers is selected. That is, by selecting the time difference between the operations of the two ignition means, the mixing ratio of the gas in the third pressure chamber changes, so that the generated pressure can be more finely controlled, and a pressure partition is provided at the gas discharge port. Because of the provision, the external release of the unburned components of the combustible gas is temporarily suppressed, and the combustion of the mixed gas in the third pressure chamber is efficiently performed.

In the gas generator according to claim 2 of the present invention, the combustible gas is a gas selected from hydrogen and hydrocarbons and a gas containing oxygen, and the first and second pressure chambers are charged under pressure. Because the composition of the flammable gas is different, the combustion speed of both flammable gases will be different,
The generated pressure changes by selecting the operation timing of the ignition means of the first and second pressure chambers.

In the gas generator according to a third aspect of the present invention, the first pressure chamber is filled with a flammable gas containing hydrogen and oxygen under pressure, and the second pressure chamber is filled with a hydrocarbon (eg, methane-based carbon). Since the flammable gas containing hydrogen and oxygen is charged under pressure, the burning rate of the flammable gas in the first pressure chamber is high, and the burning rate of the flammable gas in the second pressure chamber is low. The difference between the combustion speeds becomes more sufficient, and the generated pressure changes by selecting the operation timing of the ignition means of the first and second pressure chambers, and the change width of the generated pressure increases.

In the gas generator according to claim 4 of the present invention, the pressure dividing wall of the third pressure chamber that closes the gas discharge port is closed with respect to the pressure of the pressure dividing wall that closes the first and second pressure chambers. Since the cleavage pressure was set high, the first and second
When the gas is released from the pressure chamber of the third pressure chamber to the third pressure chamber, useless external release of the unburned components of the combustible gas is more sufficiently suppressed, and the combustion of the mixed gas in the third pressure chamber is performed more efficiently. Will be

[0017] In the gas generator according to claim 5 of the present invention, the first and second pressure chambers are arranged coaxially with the pressure partitions facing each other, and the first and second pressure chambers are connected to each other. Since the third pressure chamber is formed between the two pressure partitions, the overall structure is very compact. And, since the pressure bulkheads closing the first and second pressure chambers are arranged at intervals so as to come into contact with each other when expanded and deformed by pressure, when the operation timings of both ignition means are not simultaneous, the By selecting the time difference, the cleavage pressure of the pressure partition of the first and second pressure chambers changes, and as a result, the generated pressure changes.

That is, since the pressure partition is cleaved by the pressure difference between the inside and the outside of the room, in the case where the opposing pressure partitions expand and deform and come into contact with each other, the pressure of the own pressure chamber is higher than the pressure of the other pressure chamber. If it is not too high, no cleavage occurs. Therefore, by selecting the time difference between the operations of both ignition means and controlling the pressure difference, it becomes possible to substantially change the cleavage pressure of the pressure partition.

More specifically, for example, first and second
In the structure in which the rupture pressure of the pressure bulkhead in the pressure chamber is set to rupture at the pressure at the time when each flammable gas is half consumed, when the ignition means of the first pressure chamber is operated, When the flammable gas is half consumed, the pressure bulkheads of the first pressure chamber are cleaved. However, if the ignition means of the second pressure chamber is activated before the flammable gas is cleaved, the expanded and deformed pressure bulkheads come into contact with each other. The pressure partition of the first pressure chamber is temporarily prevented from being split at the set pressure by the pressure partition of the second pressure chamber, and is split at a pressure higher than the set pressure, that is, the pressure at the time when at least half of the combustible gas is consumed. . At this time, in the combustible gas in the first pressure chamber, the unburned component decreases with the progress of combustion with the elapse of time until the pressure partition wall breaks. Therefore, if the time difference between the time when the ignition means of the first (or second) pressure chamber is activated and the time when the ignition means of the second (or first) pressure chamber is activated is selected, the cleavage pressure of the pressure bulkhead is substantially increased. Changes, the amount of the unburned component of the combustible gas changes, and the mixture ratio of the gas in the third pressure chamber after the pressure partition breaks changes, so that the generated pressure also changes.

In the method of using the gas generator according to claim 6 of the present invention, the operation timings of both the ignition means are simultaneously set, the case where the ignition means of the first pressure chamber is activated first, and the case where the second pressure is activated. Each of the generated pressures changes in the case where the ignition means of the chamber is operated first, as described in the operation of the first to fifth aspects.

In the method of using the gas generator according to claim 7 of the present invention, when the operation timings of the two ignition means are not simultaneous, the time difference is selected.
As described above, the cleavage pressure of the pressure partition of the first and second pressure chambers changes, and as a result, the generated pressure changes.

[0022]

According to the gas generator according to the first aspect of the present invention, the first and second pressure chambers closed by the pressure partition, the third pressure chamber formed between the two pressure chambers, A pressure partition for closing a gas discharge port of the pressure chamber;
In addition, since the second pressure chamber is pressurized and filled with a flammable gas having a different combustion rate, the structure is relatively simple, the layout is more flexible, the manufacturing process is simplified and the cost is reduced. Can be realized, and the generated pressure can be changed to at least three forms only by selecting the operation timing of the ignition means in the first and second pressure chambers. By adjusting the time difference between the operations of the ignition means and the two ignition means, the generated pressure can be more finely controlled, and the degree of freedom in controlling the gas discharge speed can be greatly increased with a simple structure.

According to the gas generator according to the second aspect of the present invention, the same effect as that of the first aspect can be obtained, and in addition, the combustible gas contains a gas selected from hydrogen and hydrocarbons and oxygen. Since gas is used, it is possible to obtain a generated pressure and a variation form of the generated pressure, which are suitable as a gas generation source of, for example, an airbag system of an automobile.

According to the gas generator according to the third aspect of the present invention, the same effect as that of the second aspect can be obtained, and in addition, a combustible gas containing hydrogen and oxygen is supplied to the first pressure chamber.
By filling the second pressure chamber with a flammable gas containing hydrocarbons and oxygen under pressure, the difference between both combustion rates can be secured more sufficiently, and the range of change in the generated pressure can be increased.
Thereby, the degree of freedom in controlling the generated pressure can be further expanded.

According to the gas generator according to the fourth aspect of the present invention, the same effects as those of the first to third aspects can be obtained, and further, the cleavage of the pressure partition for closing the first and second pressure chambers. By setting the rupture pressure of the pressure partition wall that closes the gas discharge port of the third pressure chamber higher than the pressure, wasteful external release of the unburned components of the combustible gas can be suppressed more sufficiently and the third pressure can be reduced. The combustion efficiency of the mixed gas in the chamber can be increased, which can contribute to further improving the function of the gas generator.

According to the gas generator according to claim 5 of the present invention, the same effect as in claims 1 to 4 can be obtained, and the first to third pressure chambers are arranged coaxially. Thereby, the structure can be made extremely compact, which can greatly contribute to realizing the improvement of the freedom of layout, the simplification of the manufacturing process, the cost reduction, and the like.
And the pressure bulkheads closing the second pressure chamber are arranged so as to be in contact with each other when expanded and deformed by pressure, so that the generated pressure can be more finely changed only by selecting the operation time difference between the two ignition means. As a result, the degree of freedom in controlling the gas release rate can be further increased.

According to the method of using the gas generator according to claim 6 of the present invention, the operation timing of both ignition means is selected from simultaneous and non-simultaneous using the gas generator according to claims 1 to 5. The generated pressure can be changed into at least three forms by a very simple operation of, for example,
When used as a gas generation source for an airbag system of an automobile, the generation pressure, that is, the gas release speed can be freely changed according to the occupant's physique and the magnitude of the impact of a collision.

According to the method of using the gas generator according to claim 7 of the present invention, the same effect as in claim 6 can be obtained, and when the operation timings of both ignition means are not simultaneous, By selecting the time difference, the generated pressure can be changed more finely, and the degree of freedom in controlling the gas release rate can be further expanded.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a gas generator according to the present invention and a method of using the gas generator will be described with reference to the drawings. The gas generator according to this embodiment is used as a gas generation source for an airbag system of an automobile.

The gas generator 1 shown in FIG.
1 and a bottomed cylindrical first pressure vessel 21 forming the second pressure chamber 12, and a bottomed cylindrical second pressure chamber 22 forming the second pressure chamber 12.
And an annular holding member 2 for holding the two pressure vessels 21 and 22 coaxially with the openings facing each other. First and second pressure vessels 21, 22 and holding member 2
Is, for example, made of high-tensile steel.

The first and second pressure chambers 11 and 12 are closed by pressure partitions 31 and 32 fixed to the openings of the respective pressure vessels 21 and 22 by welding. In the holding member 2, the third pressure chamber 1 is provided between the opposing pressure partitions 31 and 32.
3 are formed. The holding member 2 is provided with a gas outlet 3 communicating with the outside from the third pressure chamber 13 (the number is not particularly limited), and the gas outlet 3 is provided with a pressure partition 33 for closing the gas outlet. It is.

Each of the pressure bulkheads 31 to 33 is a thin disk made of a metal selected from stainless steel, iron, aluminum and the like, and has a material and a thickness set so as to be cleaved at a predetermined pressure. These pressure partitions 31 to 33
For example, a groove is formed radially from the center, and the part where the wall thickness is reduced by the groove is used as a fragile part for promoting cleavage, and when pressure is applied, it breaks at the fragile part and breaks like a petal You can make it.

Here, each of the pressure partitions 31 to 33 has a breaking pressure of the pressure partition 33 closing the gas discharge port 3 with respect to a breaking pressure of the pressure partitions 31 and 32 closing the first and second pressure chambers. Is set large, and the difference in set pressure is 10M
It is set to Pa or more. The pressure partitions 31, 32 for closing the first and second pressure chambers are arranged at intervals so as to come into contact with each other when expanded and deformed by pressure. The distance between the two depends on the size and material of the pressure bulkhead, but is preferably smaller than the sum of the radii of the two pressure bulkheads 31 and 32, for example.

Further, the gas generator 1 includes first and second gas generators.
The pressure chambers 11 and 12 are provided with ignition means 41 and 42, and are filled with flammable gases having different combustion rates under pressure. The igniting means 41 and 42 are provided with a nichrome wire 4c between the pair of electrodes 4a and 4b. The igniting means 41 and 42 generate heat by applying electricity from the outside to ignite the combustible gas.

As the combustible gas, a gas selected from hydrogen and hydrocarbons and a gas containing oxygen are used. In this embodiment, the composition of the flammable gas to be charged under pressure into the first and second pressure chambers 11 and 12 is made different.
A flammable gas containing hydrogen and oxygen is supplied to the pressure chamber 11 in the second
The pressure chamber 12 is filled with a flammable gas containing methane and oxygen under pressure. As a result, the combustion rate of the combustible gas in the first pressure chamber 11 is high, and the combustion rate of the combustible gas in the second pressure chamber 12 is low, and the difference between the two combustion rates is sufficient. The change width of the generated pressure later becomes large, and the degree of freedom in controlling the gas release rate is further expanded.

Here, the first and second pressure vessels 11,
When each of the flammable gases 12 is filled with the flammable gas under pressure, as shown in FIG. 2, both the pressure partitions 31 and 32 are expanded and deformed to be close to each other. The tearing pressure set for the pressure partitions 31 and 32 can of course withstand the filling pressure of the flammable gas. For example, in the process of increasing the pressure by igniting the flammable gas, for example, Is set to be cleaved at the pressure at the time when half is consumed.

Next, the operation of the gas generator 1 having the above configuration and the method of using the gas generator according to the present invention will be described.

The gas generator 1 includes first to third pressure chambers 11.
By arranging １３13 coaxially, the structure is extremely compact as is clear from FIG. And
The ignition means 41 and 42 are operated by a signal from the outside,
The gas generated by the combustion of the combustible gas is released instantaneously. At this time, the generated pressure (gas release rate) depends on whether both the ignition means 41 and 42 are operated simultaneously and non-simultaneously. ) Changes.

When both ignition means 41 and 42 are operated at the same time, the flammable gas in the first and second pressure chambers 21 and 22 is burned, and both pressure partition walls 3 and 3 are raised in the process of increasing the pressure.
As shown in FIG. 3, the gases from both sides are released into the third pressure chamber 13 as shown in FIG. At this time, as described above, since both pressure bulkheads 31 and 32 are set to be cleaved at the pressure at the time when the flammable gas is half consumed, the gas released into the third pressure chamber 13 is set. Contains half of the unburned components. Therefore, in the third pressure chamber 13, both gases are mixed and burned while the pressure rises sharply due to gas release from both sides. At this time, unburned components are unburned by the pressure partition 33 closing the gas discharge holes 3. The release is temporarily suppressed, and the mixed combustion of the gases is efficiently performed. Thereafter, as shown in FIG.
Is released and gas is released. The generated pressure of the gas generator 1 at this time rises to near the maximum generated pressure in a short time.

Here, since the pressure partition ruptures due to a pressure difference between the inside and outside of the room, in a case where the opposing pressure partitions expand and deform and come into contact with each other, the pressure of the own pressure chamber becomes the pressure of the pressure chamber on the other side. Otherwise, no cleavage will occur. However, even when the two ignition means 41 and 42 are simultaneously operated as described above, the combustion speeds of both combustible gases are different, and the pressure rise in the first and second pressure chambers 11 and 12 and Since the expansion deformations of the pressure bulkheads 31, 32 cannot be exactly the same, the pressure bulkheads 31, 32 are surely torn.

When the ignition means 41 of the first pressure chamber 11 is actuated first, the pressure partition 32 of the second pressure chamber 12 is split after the pressure partition 31 of the first pressure chamber 11 is split. When the two gases are mixed and burned in the third pressure chamber 13, the pressure in the third pressure chamber 13 rises and the pressure partition 33 of the gas discharge port 3 is cleaved. At this time, the first pressure chamber 1
The first flammable gas is a gas having a high combustion rate containing hydrogen and oxygen, and the flammable gas in the second pressure chamber 12 is a gas having a low combustion rate containing methane and oxygen. As for the gas, a large amount of gas having a low burning rate is used. In other words, the combustible gas with the fast burning rate burns first, and thereafter the mixed gas mainly composed of the combustible gas with the slow burning rate burns, so that the pressure generated by the gas generator 1 increases stepwise.

When the time difference between the operations of the two ignition means 41 and 42 is extremely short, the pressure in the second pressure chamber 12 increases when the pressure partition 31 of the first pressure chamber 11 ruptures. Therefore, the pressure partition 33 of the gas discharge port 3 may be split before the pressure partition 32 of the second pressure chamber 12, and thereafter, the pressure partition 32 of the second pressure chamber 12 may be split. Also in this case, since the mixed gas in the third pressure chamber 13 is mostly a gas having a low combustion rate, the generated pressure of the gas generator 1 increases stepwise.

On the other hand, when the ignition means 42 of the second pressure chamber 12 is actuated first, the pressure partition 32 of the second pressure chamber 12 is opened and then the pressure of the first pressure chamber 11 is reduced. The partition 31 is opened, and both gases are mixed and burned in the third pressure chamber 13, so that the pressure in the third pressure chamber 13 increases and the pressure partition 33 of the gas discharge port 3 is opened. At this time, the mixed gas in the third pressure chamber 13 has a large amount of gas having a high combustion rate. In other words, the combustible gas having a slow burning rate burns first, and then the mixed gas mainly composed of the combustible gas having a fast burning rate burns. Therefore, the generated pressure of the gas generator 1 gradually increases in the initial stage, Then it rises sharply.

When the time difference between the operations of the two ignition means 41 and 42 is extremely short, the pressure in the first pressure chamber 11 increases when the pressure partition 32 of the second pressure chamber 12 ruptures. Therefore, the pressure partition 33 of the gas discharge port 3 may be split before the pressure partition 31 of the first pressure chamber 11, and thereafter, the pressure partition 31 of the first pressure chamber 11 may be split. Also in this case, since the mixed gas in the third pressure chamber 13 has a large amount of gas having a high combustion rate, the pressure generated by the gas generator 1 gradually increases in the initial stage, and then rapidly increases.

Further, in the gas generator 1, as described above, since the pressure partition breaks due to the pressure difference between the inside and the outside of the room, the generated pressure can be further increased by selecting the time difference for operating both the ignition means 41 and 42. Fine control is possible.

That is, the first and second pressure chambers 11, 1
Since the rupture pressure of the pressure bulkheads 31 and 32 in 2 is set to rupture at the pressure at the time when each flammable gas is half consumed, the ignition means 41 of the first pressure chamber 11 is operated, and Before the pressure bulkhead 31 ruptures, the second pressure chamber 1
When the second ignition means 42 is operated, the pressure bulkheads 31 and 32 which have been expanded and deformed come into contact with each other, and the cleavage of the pressure bulkhead 31 of the first pressure chamber 11 is temporarily prevented. Thereby, the first
The pressure partition 31 of the pressure chamber 11 is cleaved at a pressure higher than the set pressure, that is, the pressure at the time when the combustible gas is consumed by half or more. At this time, the combustible gas in the first pressure chamber 11 has a longer time until the pressure partition wall 31 ruptures, so that the combustion proceeds and the unburned components decrease. Therefore, after the ignition means 41 of the first pressure chamber 11 is operated, the second pressure chamber 12
If the time difference until the activation of the ignition means 42 is selected, the cleavage pressure of the pressure bulkhead 31 substantially changes, and
The order of cleavage of each of the pressure bulkheads 31 to 33 changes, thereby changing the amount of the unburned component of the combustible gas.
After the cleavage of 2, the gas mixture ratio in the third pressure chamber 13 changes, and the generated pressure also changes.

As described above, according to the gas generator 1 of the above-described embodiment and the method of using the same, the gas generator 1 has a very simple structure, and the generation pressure is at least increased only by selecting the operation timing of the ignition means 41, 42. It will be changed into three forms, and the breaking pressure of each pressure bulkhead 31, 32, 33,
By selecting the combustion speed of each combustible gas to be charged into the first and second pressure chambers 11 and 12 and the time difference of operation, fine control of the generated pressure becomes possible, and the degree of freedom in controlling the gas discharge speed is remarkable. It will be expensive.

(Example 1) In a cylindrical pressure vessel made of a high-strength steel pipe with both ends sealed, two thin metal-made pressure bulkheads that are cleaved at 10 Mpa are arranged at predetermined intervals, and are welded. The entire circumference of both pressure partitions was fixed, first and second pressure chambers were formed at both ends of the pressure vessel, and a third pressure chamber was formed between both pressure partitions. At this time, the volume of the first and second pressure chambers was set to 150 cm ^3, and the interval between the two pressure partitions was set to 20 mm. Further, in the first and second pressure chambers, a pair of electrodes were provided in an airtight state with the outside as ignition means, and a nichrome wire having a wire diameter of 30 μm was provided between the electrodes. Further, a gas discharge port communicating with the outside is provided in the third pressure chamber,
At the gas discharge port, a metal pressure partition having a thin plate shape that can be cleaved at 30 MPa was hermetically fixed by welding.

The first pressure chamber is filled with a flammable gas of 30 vol% of hydrogen, 15 vol% of oxygen and 55 vol% of argon at a pressure of 5 MPa from a separately provided gas inlet, and the gas inlet is sealed. In the second pressure chamber, as a combustible gas having a different combustion rate (composition), the immediate annual velocity methane 10 vol%, oxygen 20 vol%, argon 70 vol
1% of a flammable gas was filled under pressure at a pressure of 5 MPa, and the gas inlet was sealed to obtain a gas generator of Example 1.

(Example 2) With respect to the gas generator of Example 1, the breaking pressure of the pressure partition for closing the gas discharge port was set to 20M.
A gas generator of Example 2 was obtained with the same configuration except that Pa was used.

Embodiment 3 The composition of the combustible gas charged into the second pressure chamber under pressure was 15 vol% of hydrogen, 17 vol% of oxygen, and 68 vol of argon with respect to the gas generator of the first embodiment.
%, And the gas generator of Example 3 was obtained.

Comparative Example 1 As Comparative Example 1, a conventional type gas generator for a 45-liter driver's seat airbag was used. This gas generator uses sodium azide (NaN3)
This is a mechanism for generating a gas by thermally decomposing the gas generating agent by an ignition means that is activated by energization.

(Test Example) The gas generators of Examples 1 to 3 and Comparative Example 1 were housed in a pressure-resistant container having a capacity of 60 liters, and were operated in the pressure-resistant container to release gas. The pressure change inside was measured. At this time, in Examples 1 to 3, a test in which the ignition means of the first and second pressure chambers were simultaneously operated, and the ignition means of the first pressure chamber was set to 5
A test was performed in which the ignition means of the second pressure chamber was activated 5 msec earlier. The test results are shown in FIGS.

As is clear from the graphs of FIGS.
In the gas generators of Examples 1 to 3, it was confirmed that when both ignition means were simultaneously operated, the generated pressure increased in a shorter time than in Comparative Example 1. Further, when the ignition means of the first pressure chamber is operated first, the generated pressure changes stepwise, and when the ignition means of the second pressure chamber is operated first, the generated pressure is initially reduced. It was confirmed that it rose slowly and then steeply. In other words, by controlling the ignition timing, it is possible to change the apparent gas composition in the container, and as compared with the conventional comparative example 1, a faster gas blowing, a two-stage blowing, and a rather gentle blowing. Was realized, and it was confirmed that the internal pressure and shape of the airbag could be achieved accordingly.

[Brief description of the drawings]

FIG. 1 is a sectional view illustrating an embodiment of a gas generator according to the present invention.

FIG. 2 is a cross-sectional view showing a state where a flammable gas is pressurized and filled into first and second pressure chambers.

FIG. 3 is a cross-sectional view showing a state in which pressure barriers of first and second pressure chambers are split.

FIG. 4 is a cross-sectional view showing a state in which the pressure partition wall of the gas discharge port has been opened following FIG. 3;

FIG. 5 is a graph showing changes in generated pressure over time as test results of the gas generators of Example 1 and Comparative Example 1.

FIG. 6 is a graph showing changes in generated pressure over time as test results of the gas generators of Example 2 and Comparative Example 1.

FIG. 7 is a graph showing changes in generated pressure over time as test results of the gas generators of Example 3 and Comparative Example 1.

[Explanation of symbols]

 Reference Signs List 1 gas generator 3 gas discharge port 11 first pressure chamber 12 second pressure chamber 13 third pressure chamber 31 pressure partition of first pressure chamber 32 pressure partition of second pressure chamber 33 pressure partition of gas discharge port 41 42 ignition means

Continued on the front page (72) Inventor Jun Okada Nissan Motor Co., Ltd., 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture (72) Inventor Kiyohiro Uramoto 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa, F Terms (reference) 3D054 DD04 FF16 FF18 4G068 DA08 DB16 DB26 DC06

Claims (7)

[Claims] 1. A first pressure chamber closed by a pressure partition cleaving at a predetermined pressure, and a second pressure chamber closed by a similar pressure partition.
A pressure chamber; and a third pressure chamber formed between the two pressure partitions of the first and second pressure chambers. The first and second pressure chambers are filled with a combustible gas having a different combustion rate under pressure. And a means for igniting the combustible gas is provided, and the third pressure chamber is provided with a gas discharge port for communicating between the inside and the outside, and a pressure partition for closing the gas discharge port and cleaving at a predetermined pressure. Gas generator. 2. The method according to claim 1, wherein the combustible gas is a gas containing hydrogen and a gas selected from hydrocarbons and a gas containing oxygen, and the first and second pressure chambers have different compositions of the combustible gas under pressure. The gas generator according to claim 1, characterized in that: 3. The fuel cell according to claim 1, wherein the first pressure chamber is filled with a flammable gas containing hydrogen and oxygen under pressure, and the second pressure chamber is filled with a flammable gas containing hydrocarbon and oxygen under pressure. The gas generator according to claim 2, wherein 4. A pressure dividing wall for closing a gas discharge port of a third pressure chamber is set to be larger than a breaking pressure of a pressure partition for closing the first and second pressure chambers. The gas generator according to claim 1. 5. The first and second pressure chambers are arranged coaxially with the pressure partitions facing each other, and a third pressure chamber is formed between the two pressure partitions of the first and second pressure chambers. And
The gas generator according to any one of claims 1 to 4, wherein the pressure partition walls for closing the first and second pressure chambers are arranged at intervals so as to be in contact with each other when expanded and deformed by pressure. . 6. The gas generator according to any one of claims 1 to 5, wherein the operation timing of both ignition means in the first and second pressure chambers is selected from simultaneous and non-simultaneous to set the gas generator. Use of a gas generator characterized by being operated. 7. The gas generator according to claim 6, wherein the operation timings of both ignition means in the first and second pressure chambers are not simultaneous, and the time difference is selected to operate the gas generator. How to use the gas generator.