JPH106911A - Gas generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold pressure of a gas generating agent in the combustion range, stabilize combustion of the gas generating agent so as to more perfectly burn, and attain downsizing and weight reduction in a simple construction. SOLUTION: An ignition device 12 and a receiving case 18 arranged adjacent to it and receiving a gas generating agent 17 are arranged on one end of a receiving vessel 11. A cylindrical sleeve 20 is arranged on the other part in the receiving vessel 11. A first space part 25 is formed in the sleeve 20. A second space part 27 is formed between the receiving vessel 11 and the sleeve 20. The sleeve 20 is provided with communicating holes 30, and the receiving vessel 11 is provided with release holes 29. The communicating hole 30 and the release hole 29 are provided so as to be positioned opposite to each other by 180 deg. in the circumferential direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas generator suitable for use in an airbag mounted on a driver's seat in a vehicle, for example.

[0002]

2. Description of the Related Art As a device for protecting a vehicle occupant from a shock at the time of a collision, an airbag device for instantly inflating and deploying an airbag at the time of a collision is known. This airbag device includes an airbag, a gas generator for generating gas for inflating the airbag, and a sensor circuit for sensing a shock of a collision and transmitting a signal for operating the gas generator.

The types of the airbag device include a driver's seat airbag device for protecting the occupant from frontal and oblique collisions, a passenger's seat airbag device, and a side collision airbag device for protecting the occupant from side collision. BACKGROUND ART Bag devices, knee airbag devices for protecting knees, and airbag devices for preventing whiplash are known.

Among them, US Pat. No. 5,094,944 discloses a gas generator used in a side collision airbag device.
A configuration disclosed in Japanese Patent Publication No. 75 is known. That is, as shown in FIG. 11, a cylindrical gas generator is accommodated in the airbag 41.
This gas generator includes a cylindrical tube 42 and a gas generator 43 attached to one end of the tube 42. The tube 42 is provided with a plurality of discharge holes 44 for releasing gas into the airbag 41 at predetermined intervals in the axial direction of the tube 42.

An igniter 47 to which a lead wire 46 is connected is disposed in a housing 45 of the gas generator 43, and a gas generating agent 48 made of nitrocellulose which is burned by the ignition of the igniter 47 is accommodated therein. . A partition 49 is provided at an end of the tube 42 to partition a space between the tube 42 and the gas generating agent 48 in the housing 45.

When the igniter 47 ignites by energization from the lead wire 46, the gas generating agent 48 burns to generate a predetermined gas, and the partition 49 is broken by the expansion pressure of the gas. The generated gas is released from the space in the tube 42 into the airbag 41 through the discharge hole 44, and the airbag 41 is inflated and deployed.

On the other hand, the applicant of the present application has previously proposed a gas generator for deploying an airbag (Japanese Patent Application Laid-Open No. 7-52744). That is, an ignition mechanism is provided on one end side in a cylindrical housing, and an inner cylinder is disposed in the remaining portion, and a gas generating agent is accommodated therein. The inner cylinder is provided with a large number of gas flow holes arranged in the circumferential direction and the axial direction, and the housing is similarly provided with a large number of gas discharge holes in the circumferential direction and the axial direction. A predetermined space is formed between the housing and the inner cylinder, and the space contains a coolant.

[0008] When the ignition mechanism is ignited, the gas generating agent in the inner cylinder burns to generate gas, and the gas flows out of the gas flow hole of the inner cylinder. The gas is cooled by the coolant, and is discharged outward from gas discharge holes of the housing.

[0009]

However, in the technique disclosed in the above-mentioned U.S. Patent, the gas generated by the gas generating agent at one end in the housing enters a large space in the tube and is discharged from the discharge hole. Released quickly.
For this reason, the pressure of the generated gas entering the space rapidly decreases. As a result, the combustion of the gas generating agent is interrupted, the gas generating agent during combustion flows into the airbag, the gas generating agent is incompletely burned, and toxic carbon monoxide and the like increase in the combustion gas. There was a problem that In order to solve such a problem, it is necessary to cope with the problem by elongating the tube, which causes a new problem that the gas generator becomes large and heavy.

On the other hand, in the technique disclosed in Japanese Patent Application Laid-Open No. 7-52744, the gas generated by the combustion of the gas generating agent is quickly discharged from the gas discharge hole of the housing through the gas flow hole of the inner cylinder. Is done. For this reason, there is a problem that the gas generated by the combustion of the gas generating agent is released before the gas is completely burned while maintaining the predetermined pressure.

The present invention has been made by focusing on the problems existing in the prior art as described above. It is an object of the present invention to provide a gas generator capable of maintaining a pressure in a combustion region of a gas generating agent, stabilizing combustion of the gas generating agent, and performing more complete combustion. Another object is to provide a gas generator that has a simple structure and can be reduced in size and weight.

[0012]

In order to achieve the above object, in a gas generator according to a first aspect of the present invention, at least one end in a cylindrical storage container is ignited by an ignition device and the ignition of the ignition device causes combustion. A storage case loaded with a gas generating agent for generating a gas is disposed, a cylindrical sleeve is disposed in other portions, a first space portion is provided in the sleeve, and a second space is provided between the storage container and the sleeve. A space portion is provided, a communication hole through which gas flows from the first space portion to the second space portion is provided in the sleeve, and a discharge hole for releasing gas from the second space portion to the outside is provided in the storage container. .

According to a second aspect of the present invention, in the gas generator of the first aspect, the communication hole of the sleeve and the discharge hole of the container are provided at different positions in the circumferential direction.

According to a third aspect of the present invention, in the gas generator of the first or second aspect, the communication hole of the sleeve and the discharge hole of the container are separated from each other in the axial direction of the container. It is provided.

According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, a coolant for cooling gas is disposed in the second space. Therefore, in the gas generator according to the first aspect of the invention, the cylindrical sleeve is provided in the storage container, and the first space is provided in the sleeve. Furthermore, a communication hole is provided in the sleeve, and a discharge hole is provided in the storage container, and gas is discharged through two steps of the communication hole of the sleeve and the discharge hole of the storage container.

For this reason, the gas generated by the combustion of the gas generating agent in the combustion section is introduced into the first space as a combustion area, and a predetermined high pressure is maintained in the first space.
As a result, the combustion of the gas generating agent in the combustion region becomes stable, and the combustion is more completely performed. Then, the combustion gas is discharged from the communication hole of the sleeve, through the second space portion, and from the discharge hole of the storage container.

In the gas generator according to the second aspect of the present invention, the communication hole of the sleeve and the discharge hole of the container are provided at different positions in the circumferential direction. For this reason, the distance of the gas flow path until the combustion gas introduced into the second space from the communication hole is discharged from the discharge hole becomes longer, and the pressure of the first space in the sleeve can be maintained higher. it can.

In the gas generator according to the third aspect of the invention, the communication hole of the sleeve and the discharge hole of the container are provided so as to be separated from each other in the axial direction of the container.
The distance from the communication hole to the discharge hole is set long. For this reason, the distance of the gas flow path from the communication hole to the discharge hole of the combustion gas introduced into the second space increases, and the pressure in the first space in the sleeve can be kept higher.

In the gas generator of the fourth invention, a coolant for cooling the gas is disposed in the second space. Therefore, it is possible to cool the gas passing through the second space, increase the pressure in the second space, and maintain the pressure in the first space in the sleeve higher.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

As shown in FIGS. 1 (a) and 1 (b), the storage container 11 has a bottomed cylindrical shape, and a tubular body 13 of an ignition device 12 is screwed to an open end thereof. This container 1
1 is formed of an aluminum alloy (Japanese Industrial Standard A5056), but may be formed of stainless steel, carbon steel, cast iron, a titanium alloy, a magnesium alloy, or the like. The igniter 14 is fitted and fixed in the cylinder 13 of the ignition device 12 via the holding cylinder 15.

As the igniter 16, a mixture containing boron and potassium nitrate as main components, a mixture of magnesium and polytetrafluoroethylene with a binder, or the like is used. A storage case 18 serving as a combustion unit that stores the gas generating agent 17 is formed of aluminum in a cylindrical shape with a bottom, and is disposed in the storage container 11 adjacent to the ignition device 12. The opening end of the storage case 18 is fixed by caulking to the holding cylinder 15 at a caulking portion 19. The bottom side of the storage case 18 is the stepped portion 2 of the storage container 11.
2, the movement is regulated.

Examples of the gas generating agent 17 include fuels such as nitrogen-containing compounds such as sodium azide, tetrazole and azodicarbonamide, and nitrogen-free organic compounds such as cellulose acetate. A composition containing an agent, a known smokeless explosive, a composition obtained by adding an oxidizing agent to a smokeless explosive composition, and the like are used.

As shown in FIGS. 1A and 3, the cylindrical sleeve 20 is configured such that the enlarged diameter portion 21 at one end of the cylindrical container 20 is located near the step 22 of the container 11.
(1) An engagement protrusion (2) fitted on the inner peripheral surface and having a quadrangular prism shape at the other end.
3 is fitted in the engagement recess 24 of the storage container 11. The sleeve 20 is made of stainless steel (Japanese Industrial Standard SUS30).
Although it is formed by 4), it may be formed by aluminum alloy, carbon steel, cast iron, titanium alloy, magnesium alloy or the like. The first space 25 is formed in the sleeve 20 and serves as a combustion area for the gas generating agent 17. Compartment wall 2
6 is formed at the bottom of the storage case 18,
And the first space 25 are partitioned.

The gas generating agent 1 in the storage case 18
7, the partition wall 26 is broken by the pressure of the gas, and the gas flows into the first space 25, and the gas generating agent 17 also burns in the first space 25. The second space portion 27 is formed in an annular shape between the housing container 11 and the sleeve 20, and houses a metal coolant 28. This second space 2
7, the width between the container 11 and the sleeve 20, which form
That is, the radial distance is set in the range of 0.5 to 10 mm, and preferably in the range of 1 to 5 mm.

As shown in FIGS. 1 (a), 1 (b) and 2, the discharge holes 29 are provided in the container 11 at predetermined intervals in a line in the axial direction. The communication hole 30 is the sleeve 2
At a position 180 ° apart from the discharge hole 29 in the circumferential direction, the discharge hole 29 is provided at a predetermined interval so as to be arranged in a line in the axial direction. Then, the high-temperature combustion gas enters the second space 27 from the first space 25 through the communication hole 30, is further turned around by 180 degrees in the circumferential direction, is cooled by the coolant 28, and is discharged from the discharge holes 29. As the cooling material 28, for example, a 24 mesh stainless steel plain woven wire mesh formed into a cylindrical shape is used.

The storage container 11 has a length of 50 to 30.
0 mm, an outer diameter of 15 to 40 mm, and an inner diameter of 10 to 38 mm are preferable. The sleeve 20 has a length of 40 to 290 mm and an outer diameter of 8 to
A range of 36 mm and an inner diameter of 7 to 35 mm is preferable. The area of one discharge hole 29 is preferably 3 to 200 mm ² , and the total area of the discharge hole 29 is preferably 40 to ²⁰⁰ mm ² . The area of one communication hole 30 is preferably 3 to 150 mm ² , and the total area of the communication hole 30 is preferably 30 to 150 mm ² . Communication hole 3
The ratio of the total area of the discharge holes 29 to the total area of 0 is 0.0.
It is desirably in the range of 8 to 4. This is because the pressure of the gas in the first space 25 can be kept high and the gas can be released smoothly.

When assembling the gas generator, first, the sleeve 20 is inserted into the inner part of the container 11, and the engaging projection 23 is fitted into the engaging recess 24 of the container 11. Next, the one in which the opening of the storage case 18 in which the gas generating agent 17 is stored is caulked and fixed to the holding cylinder 15 by the caulking portion 19 is inserted into the storage container 11. After that, the igniter 16 and the igniter 14 are mounted, and the cylinder 13 is screwed into the container 11. Thus, a predetermined gas generator is obtained.

When the igniter 14 is ignited, the igniter 16 is ignited, and the flame causes the gas generating agent 17 in the storage case 18 to burn to generate combustion gas. The partition wall 26 at the bottom of the storage case 18 is broken by the pressure of the combustion gas, and the combustion gas flows into the first space 25.

In the first space 25, the pressure increases due to the inflow of the combustion gas. Then, the gas in the first space portion 25 flows to the second space portion 27 through the communication hole 30 of the sleeve 20. In the second space 27, the gas moves in the circumferential direction toward the discharge hole 29 of the storage container 11, during which the gas is cooled by the coolant 28. Then, the gas that has moved 180 degrees in the circumferential direction is discharged from the discharge holes 29.

At this time, since the communication hole 30 of the sleeve 20 and the discharge hole 29 of the storage container 11 are provided at positions opposite to each other by 180 degrees in the circumferential direction, the gas moves in the second space 27 as the gas moves. The residence time is prolonged and a resistance is generated. Therefore, the gas pressure in the first space 25 is maintained at a predetermined high pressure. Therefore, a sudden decrease in pressure when gas generated by combustion of the gas generating agent 17 in the storage case 18 breaks the partition wall 26 is suppressed. Therefore, the gas generating agent 17 also stably burns in the first space portion 25 to generate combustion gas. As a result, the gas generating agent 17 burns more completely.

The following effects are exhibited by the above embodiment. (1) The communication hole 30 of the sleeve 20 and the discharge hole 29 of the storage container 11 are provided so as to be located on opposite sides of 180 degrees in the circumferential direction. A resistance force is generated, so that the gas pressure in the first space portion 25, which is the combustion region of the gas generating agent, can be maintained at a predetermined high pressure. (2) The pressure at which the pressure in the first space 25 can be maintained at a predetermined pressure, and the pressure at which the gas generated by the combustion of the gas generating agent 17 in the storage case 18 breaks through the partition wall 26 and flows into the first space 25. The decrease can be suppressed, and the combustion of the gas generating agent 17 can be stabilized. (3) Therefore, the gas generating agent 17 can be more completely burned. (4) The gas generator is provided with the sleeve 2 in the storage container 11.
0, the discharge hole 29 of the container 11 and the sleeve 20
The position of the communication hole 30 can be changed by 180 degrees in the circumferential direction, so that the structure can be simplified. (5) The gas generator does not need to be lengthened as in the related art, and can be reduced in size and weight. (Second Embodiment) Next, a second embodiment will be described with reference to FIGS. In the second embodiment, parts different from the first embodiment will be mainly described.

Now, as shown in FIGS.
Are formed in a staggered manner so as to extend in the axial direction at predetermined intervals in the storage container 11. The communication hole 30 is the discharge hole 29
Are formed in a zigzag pattern so as to be located between the discharge holes 29 on the side opposite to the circumferential direction by approximately 180 degrees.

According to the second embodiment, since the communication hole 30 and the discharge hole 29 are located on the opposite side in the circumferential direction by approximately 180 degrees and at different positions in the axial direction, the distance between the two holes 29 and 30 is small. Can be kept long, and the residence time of the gas in the second space 27 can be lengthened. Therefore, the gas pressure in the first space portion 25 can be kept high, and the gas generating agent 17 can be more completely burned. Third Embodiment Next, a third embodiment will be described with reference to FIGS. In the third embodiment, portions different from the first embodiment will be mainly described.

Now, as shown in FIGS.
0 is formed in a cylindrical shape, and the other end is open. The bolt 31 is a female screw 32 formed on the inner surface of the other end of the container 11.
Is screwed into. This bolt 31 allows the sleeve 20
Is closed, and a first space portion 25 is formed.
The discharge holes 29 are formed at four locations in the storage container 11 on the storage case 18 side at intervals of 90 degrees in the circumferential direction. The communication holes 30 are formed at four locations in the sleeve 20 on the bolt 31 side, separated by 90 degrees in the circumferential direction. The discharge holes 29 and the communication holes 30 are provided at corresponding positions in the circumferential direction.

According to the third embodiment, the positions of the discharge hole 29 and the communication hole 30 are separated from each other in the axial direction, and the two holes 29,
Since the distance between 30 is long and the residence time of the gas in the second space 27 can be lengthened, the pressure of the gas in the first space 25 can be kept high, and the gas generating agent 17 can be more completely burned. (Fourth Embodiment) Next, a fourth embodiment will be described with reference to FIG. In the fourth embodiment,
Mainly, portions different from the first embodiment will be described.

As shown in FIG. 8, an ignition device 12 and a storage case 18 loaded with a gas generating agent 17 are provided symmetrically at both ends of the storage container 11. According to the fourth embodiment, the storage case 18 storing the gas generating agent 17
Are on both sides, the amount of gas generated can be increased, the capacity of the airbag inflated and deployed by the combustion gas can be increased, and a plurality of airbags can be inflated and deployed. Moreover, by operating the left and right ignition devices 12 with a predetermined time difference, a more preferable internal pressure of the airbag can be obtained.

[0038]

EXAMPLES Next, Examples and Comparative Examples embodying the present invention will be specifically described. The performance of the gas generator of the first embodiment was evaluated.

That is, the container 11 was formed of an aluminum alloy, and had a length of 160 mm, an outer diameter of 20 mm, and an inner diameter of 15 mm. The discharge holes 29 had a diameter of 6 mm and were provided in six pieces. The sleeve 20 is made of stainless steel, has a length of 100 mm and an outer diameter of 1 mm.
1 mm, the inner diameter was 8 mm, and the depth of the first space portion 25 was 85 mm.
The communication holes 30 had a diameter of 4 mm and were provided in six pieces.

As a gas generating agent 17, 4 g of a single-base smokeless explosive mainly composed of nitrocellulose having a single pore shape
And a mixture of 0.4 g of a mixture of boron and potassium nitrate was used as the ignition charge 16. The single-base smokeless explosive can be used in the range of 2.5 to 8 g, and the ignition charge 16 in which boron and potassium nitrate are mixed is 0.1 to 0.1 g.
It can be used in the range of 1-2 g.

Then, the gas generator was accommodated in a 60-liter tank, and the igniter 14 was ignited, and the time change of the tank internal pressure was measured. The result is shown in FIG. Also,
As a comparative example, a gas generator having a structure in which the sleeve 20 was removed from the gas generator of the first embodiment was used, and other conditions were set to be the same as those of the gas generator of the first embodiment.
The time change of the pressure in the tank was measured in the same manner as in the example. The results are shown in FIG. In FIGS. 9 and 10,
The time on the horizontal axis is millisecond (ms).

As shown in FIG. 9, in the gas generator of the embodiment, the gas generating agent 17 was completely burned, and the maximum pressure in the tank reached 1.9 kgf / cm ² . In contrast, FIG.
As shown in the above, in the gas generator of the comparative example, 0.4 g of the gas was left unburned due to incomplete combustion of the gas generating agent 17, and the maximum tank pressure was only 1.0 kgf / cm ² .

The present invention can be embodied by changing the form as follows. (A) In the third embodiment, the discharge hole 29 and the communication hole 3
And 0 are staggered in the circumferential direction. (B) In each embodiment, the discharge hole 29 and the communication hole 30
And a combination of holes of different sizes. (C) The coolant 28 is accommodated in the first space 25, and the gas generated by the combustion of the gas generating agent 17 is immediately cooled. (D) The cross-sectional shapes of the storage container 11 and the sleeve 20 are formed in an elliptical shape, a rectangular shape, or the like. (E) The shape of the discharge hole 29 and the communication hole 30 is formed in an elliptical shape, a rectangular shape, or the like. Alternatively, each of the discharge hole 29 and the communication hole 30 is one elongated hole.

Further, the technical idea grasped from the above embodiment will be described below. (1) The gas generator according to claim 1, wherein both ends of the sleeve are fitted to a storage container.

With such a configuration, it is possible to prevent the sleeve in the storage container from being displaced. (2) The communication hole of the sleeve and the discharge hole of the storage container are provided at positions different by 180 degrees in the circumferential direction.
A gas generator according to claim 1.

With such a configuration, the distance between the communication hole and the discharge hole can be set long, the pressure of the combustion gas in the combustion region of the gas generating agent can be maintained, and the combustion of the gas generating agent can be stabilized to achieve more complete combustion. Combustion can be obtained. (3) The container and the sleeve are formed in a cylindrical shape,
The gas generator according to any one of claims 1 to 3, wherein a plurality of discharge holes of the storage container and a plurality of communication holes of the sleeve are provided so as to extend in the axial direction.

With this configuration, the pressure in the first space can be maintained at a predetermined pressure, and the gas can be released smoothly. (4) The gas generator according to claim 3, wherein a plurality of communication holes of the sleeve and discharge holes of the storage container are provided at predetermined intervals in a circumferential direction.

With this configuration, the distance between the communication hole and the discharge hole can be set long, the pressure of the combustion gas in the combustion region of the gas generating agent can be maintained, and the combustion of the gas generating agent can be stabilized. Complete combustion can be obtained.

[0049]

As described above in detail, according to the present invention, the following excellent effects can be obtained. According to the gas generator of the first invention, the pressure of the combustion gas in the combustion region of the gas generating agent can be maintained, the combustion of the gas generating agent can be stabilized, and more complete combustion can be obtained. In addition, the first space portion and the second space portion are defined by the sleeve, and the communication hole is provided in the sleeve and the discharge hole is provided in the storage container, so that the gas generator can be reduced in size and weight. .

According to the gas generator of the second invention, the pressure in the first space in the sleeve can be kept higher, the combustion of the gas generating agent can be stabilized, and more complete combustion can be obtained.

According to the gas generator of the third aspect of the present invention, the pressure in the first space in the sleeve can be kept higher, the combustion of the gas generating agent can be stabilized, and more complete combustion can be achieved. Obtainable.

According to the gas generating apparatus of the fourth invention, the gas generated by the combustion of the gas generating agent can be effectively cooled, and the pressure in the first space in the sleeve can be increased. Combustion can be stabilized, and more complete combustion can be obtained.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view illustrating a gas generator according to a first embodiment of the present invention, and FIG. 1B is a plan view illustrating the gas generator.

FIG. 2 is a sectional view taken along line 2-2 in FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 in FIG. 1;

FIG. 4 is a partial plan view showing a gas generator according to a second embodiment.

FIG. 5 is a sectional view taken along line 5-5 in FIG. 4;

FIG. 6 is a sectional view showing a gas generator according to a third embodiment.

FIG. 7 is a sectional view taken along the line 7-7 in FIG. 6;

FIG. 8 is a sectional view showing a gas generator according to a fourth embodiment.

FIG. 9 is a graph showing the relationship between tank internal pressure and time in the example.

FIG. 10 is a graph showing a relationship between pressure in a tank and time in a comparative example.

FIG. 11 is a partially broken front view showing a conventional gas generator.

[Explanation of symbols]

11: container, 12: ignition device, 17: gas generating agent,
18 ... storage case as a combustion part, 20 ... sleeve, 2
5 first space portion, 27 second space portion, 28 coolant, 2
9: release hole, 30: communication hole.

Claims (4)

[Claims] At least one end of a cylindrical storage container is provided with an ignition device and a storage case loaded with a gas generating agent which generates gas by burning by ignition of the ignition device, and a cylindrical sleeve is provided at another portion. Is provided, a first space portion is provided in the sleeve, a second space portion is provided between the housing container and the sleeve, and a communication hole through which gas flows from the first space portion to the second space portion is provided in the sleeve. A gas generating device provided with a discharge hole for discharging gas outward from the second space portion in the storage container. 2. The gas generator according to claim 1, wherein the communication hole of the sleeve and the discharge hole of the storage container are provided at different positions in the circumferential direction. 3. The gas generator according to claim 1, wherein the communication hole of the sleeve and the discharge hole of the storage container are provided so as to be separated from each other in the axial direction of the storage container. 4. The gas generator according to claim 1, wherein a coolant that cools gas is disposed in the second space.