JP2001219811A - Gas generator for air bag and air bag device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas generator for an air bag, provided with simple construction ensuring protection of a crew in such a manner that it is operated without giving the least impact to the crew at the initial stage and then a gas pressure is rapidly increased. SOLUTION: This gas generator for an air bag comprises a housing having a gas exhaust port, storing single ignition means operated with impact and a gas generating agent to be ignited an burned by the igniting means to generate a combustion gas. The housing has a combustion chamber where the gas generating agent is burned and the combustion chamber has a space portion held where no gas generating agent of preset capacity exists, so that the combustion capacity of the gas generating agent is expanded to the space portion during ignition and burning of the gas generating agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas generator for an airbag which protects an occupant from an impact, and more particularly to a gas generator for an airbag which is characterized by its operation performance.

[0002]

2. Description of the Related Art When a vehicle such as an automobile collides at a high speed, an inertia is used to prevent a passenger from smashing into a hard part inside the vehicle, such as a steering wheel or a front glass, to prevent injury or death. Quickly inflates the bag with gas,
An airbag system is installed to prevent passengers from hitting dangerous places.

[0003] Such an airbag system can be used even if the occupant's physique (for example, a person with a high or low sitting height, an adult or a child, etc.), or his / her riding posture (for example, a posture holding on to a steering wheel) is different. It is desirable that the occupant can be restrained safely. Therefore, conventionally, an airbag system has been proposed which operates in the early stage of operation with as little impact as possible on the occupant.

[0004] In Japanese Patent Application Laid-Open No. Hei 8-207696, gas is generated in two stages, the bag is inflated relatively slowly in the first stage, and gas is rapidly generated in the second stage.
The use of capsules of different types of gas generating agents has been proposed, but has the drawback that the structure inside the gas generator is complicated, the size of the container becomes large, and this increases the cost.

Also, in US Pat. No. 4,998,751 and US Pat. No. 4,950,458, two combustion chambers are provided to regulate the operation function of the gas generator, and the gas generating agent is burned in two stages. It has been proposed, but its structure is complicated and not yet sufficient.

[0006]

SUMMARY OF THE INVENTION The present invention, while having a simple structure, operates in the initial stage of operation with as little impact on the occupant as possible and in a subsequent operation stage. An object of the present invention is to provide a gas generator for an airbag that can surely protect a passenger.
For example, in a gas generator for the driver's seat, the inflation speed of the airbag during 10 ms from the start of operation of the gas generator is made slower than before, and the occupant is sufficiently restrained after 30 to 50 ms. It is an object of the present invention to provide an airbag gas generator exhibiting such an operation performance.

[0007]

A gas generator for an air bag according to the present invention is provided with a combustion chamber in which a gas generating agent is burned in a housing of the gas generator, and a predetermined volume of the gas generating agent is provided in the combustion chamber. The space that does not exist is secured, and the combustion volume of the gas generating agent is expanded to the space at the time of ignition and combustion of the gas generating agent, thereby adjusting the timing of ignition and combustion of the gas generating agent. The above object is achieved by suppressing the impact on the occupant.

That is, in the gas generator for an air bag of the present invention, a single ignition means operated by an impact is provided in a housing having a gas discharge port, and the ignition means ignites and burns to generate combustion gas. A gas generator for an airbag containing and containing a gas generating agent, wherein a combustion chamber for burning the gas generating agent is provided in the housing, and a predetermined volume of the gas generating agent is provided in the combustion chamber. A space in which the gas generating agent does not exist is secured, and the combustion volume of the gas generating agent is expanded to the space when the gas generating agent is ignited and burned.

The space inside the combustion chamber can be secured, for example, by distributing the gas generating agent in a solid state on either the upper or lower side of the combustion chamber, or by partitioning the combustion chamber with a partition member. Since the space also functions as a space for the gas generating agent to burn, it communicates with the gas generating agent housing at any timing when the gas generating agent ignites or burns, and Must be performed. Therefore, when the space is formed by partitioning the combustion chamber with the partition member, the partition member is deformed and / or displaced and / or destroyed by combustion of the gas generating agent, or burns to generate gas. The medicine container and the space are communicated.

As such a partition member which is deformed and / or displaced and / or destroyed by combustion of the gas generating agent, for example, the whole of the partition member is deformed and / or displaced and / or destroyed, or the partition member is A part thereof, for example, a pressure receiving surface in contact with the gas generating agent is formed so as to be deformed and / or destroyed by combustion of the gas generating agent. The deformation and / or destruction of the whole or a part of the partition member due to the combustion of the gas generating agent is caused by the deformation and / or the deformation of the partition member by burning the gas generating agent at any place (for example, a pressure receiving portion).
Alternatively, it can also be realized by forming a fragile portion that breaks and communicates the gas generating agent storage portion and the space portion. In the case of forming a fragile portion on the pressure receiving surface, for example, a hole is provided in the pressure receiving portion, an upper portion and / or a lower portion of the bow portion is closed with a sheet member, and a portion closed with the sheet member is referred to as a fragile portion. You can do it. In addition, a notch groove for cutting by combustion of the gas generating agent may be provided on the front surface or the back surface of the pressure receiving portion, and the notch groove may be a weak portion.

[0011] When the gas generating agent accommodating portion and the space are communicated by the displacement of the partition member to increase the gas generating agent combustion volume, the partition member is provided so as to be movable into the combustion chamber. The partition member is moved (displaced) toward the space by the combustion of the gas generating agent, so that the volume of the gas generating agent storage section can be increased.

Further, the partition member supports the pressure receiving surface in contact with the gas generating agent, thereby preventing the gas generating agent from moving and pulverizing due to vibration.

As shown in the above embodiment, the gas generator for an air bag according to the present invention has an ignition means operated by impact, a combustion gas ignited by the ignition means and burned in a housing having a gas discharge port. And a gas generating agent for generating a gas, and a filter means for cooling the combustion gas and / or collecting combustion residues, if necessary, in the housing. Is done.

The housing having the gas discharge port can be formed by casting, forging, pressing, or the like. Preferably, the diffuser shell having the gas discharge port and the closure shell having the ignition means receiving port are welded. Formed. The two shells can be joined by various welding methods, for example, electron beam welding, laser welding, TIG welding, prosection welding and the like. When the diffuser shell and the closure shell are formed by pressing various steel plates such as a stainless steel copper plate, both shells can be easily manufactured and the manufacturing cost can be reduced. Further, by forming both shells into a simple and simple cylindrical shape, the press working becomes easy. As for the material of the diffuser shell and the closure shell, a stainless steel plate is preferable, but a nickel-plated steel plate may be used. Moreover, after arranging an inner cylinder member in this housing to define a space in the housing into two or more rooms,
Each member can be appropriately accommodated.

Further, as the single ignition means which operates by the above-mentioned impact, it is preferable to use an electric ignition type ignition means which operates by an electric signal transmitted from an impact sensor which senses the impact. The electric ignition type ignition means includes an electric sensor that senses an impact mainly by an electric mechanism, an igniter that operates with an electric signal transmitted from the sensor that senses the impact, and an ignition / ignition device that operates by the igniter. Combustion powder. As this electric sensor, for example, there is a semiconductor type acceleration sensor. In this semiconductor type acceleration sensor, four semiconductor strain gauges are formed on a beam of a silicon substrate which bends when an acceleration is applied, and these semiconductor strain gauges are bridge-connected. When acceleration is applied, the beam bends, causing surface distortion. Due to this distortion, the resistance of the semiconductor strain gauge changes, and the resistance change is detected as a voltage signal proportional to the acceleration. In particular, the electric ignition type ignition means can further include a control unit having an ignition determination circuit. In this case, a signal from the semiconductor type acceleration sensor is input to an ignition determination circuit, and when the shock signal exceeds a certain value, the control unit starts calculation, and when the calculation result exceeds a certain value, gas generation occurs. Outputs an operation signal to the vessel.

If necessary, the filter means housed and arranged in the housing is provided with a housing for the purpose of removing the residue and / or cooling the combustion gas when a combustion residue is generated by the combustion of the gas generating agent. It is arranged in.
If a gas generating agent that does not generate combustion residues is used,
This filter means can be omitted. This filter means is often substantially cylindrical and is located outside the location where the gas generant is stored. Examples of such a material include a conventionally used filter for purifying generated gas and / or a coolant for cooling generated gas, and a wire mesh made of an appropriate material is formed into an annular laminate, and compression molded. A laminated wire mesh filter or the like can also be used.
More specifically, with respect to the laminated wire mesh filter, a flat knitted stainless steel wire mesh is formed in a cylindrical body, and one end of the cylindrical body is repeatedly bent outward to form an annular laminated body. Compression molding in the inside, or a flat knitted stainless steel wire mesh is formed in a cylindrical body, this cylindrical body is pressed in the radial direction to form a plate, and the plate is wound into a cylindrical shape in multiple layers. A laminate can be formed and then molded by compression molding in a mold. As the material of the wire mesh, stainless steel such as SUS304, SUS310S, and SUS316 (JIS standard symbol) can be used. SUS304 (18Cr-8N
i-0.06C) stainless steel shows excellent corrosion resistance as an austenitic stainless steel. The filter means may also be a double structure having a layer of laminated wire mesh inside or outside. The inner layer may have a filter means protection function for protecting the filter means from the flame of the ignition means ejected toward the filter means and the combustion gas of the gas generating agent ignited and burned by the flame. The outer layer also prevents swelling of the filter means so that the filter means does not swell due to gas pressure when the gas generator is activated and does not block the gap formed between the filter means and the housing peripheral wall. It can function as a deterrent. The function of suppressing the swelling of the filter means can also be realized by supporting the outer periphery of the filter means with an outer layer made of a laminated metal mesh, a porous cylinder, an annular belt or the like.

In the present invention, it is particularly preferable to use a non-azide gas generating agent as the gas generating agent. As the non-azide gas generating agent, those comprising the following nitrogen-containing compound, oxidizing agent, slag forming agent and binder are preferable. Further, the following slag forming agent can be blended as required.

Examples of the nitrogen-containing compound include one or a mixture of two or more selected from the group consisting of a triazole derivative, a tetrazole derivative, a guanidine derivative, an azodicarbonamide derivative, and a hydrazine derivative. Specific examples of these include 5-oxo-1,2,4-triazole, tetrazole, 5-aminotetrazole, 5,5′-
Bi-1H-tetrazole, guanidine, nitroguanidine, cyanoguanidine, triaminoguanidine nitrate,
Examples thereof include guanidine nitrate, guanidine carbonate, biuret, azodicarbonamide, carbohydrazide, carbohydrazide nitrate complex, oxalic acid dihydrazide, and hydrazine nitrate complex.

Among these nitrogen-containing compounds, one or more selected from the group consisting of a tetrazole derivative and a guanidine derivative are preferable, and particularly, nitroguanidine,
Preferred are cyanoguanidine and 5-aminotetrazole, and most preferred is nitroguanidine because of the small number of carbon atoms in the molecule. There are two types of nitroguanidine: needle-like crystalline low-density nitroguanidine and bulk crystalline high-density nitroguanidine, both of which can be used.However, in terms of safety and ease of handling in the presence of a small amount of water, high nitroguanidine is required. The use of specific gravity nitroguanidine is preferred. The proportion of the nitrogen-containing compound in the gas generating agent varies depending on the number of carbon elements, hydrogen elements and other oxidized elements in the molecular formula, but is usually preferably in the range of 25 to 56% by weight, and more preferably 30 to 40% by weight. %
Is particularly preferred.

The absolute value of the compounding ratio of the nitrogen-containing compound differs depending on the type of the oxidizing agent in the gas generating agent. Below that, trace NOx in the generated gas
The concentration increases. Therefore, the range in which the optimum balance between the two is maintained is most preferable.

As the oxidizing agent used for the gas generating agent, various ones can be used, and an oxidizing agent selected from at least one of nitrates containing a cation selected from alkali metals or alkaline earth metals is preferable. . An oxidizing agent other than nitrate, that is, an oxidizing agent widely used in the field of airbag inflators such as nitrite and perchlorate may also be used, but the number of oxygen in nitrite molecules is reduced as compared to nitrate, or the amount outside the bag is reduced. Nitrate is preferred from the viewpoint of, for example, reducing the generation of fine mist that is easily released to the air. Examples of the nitrate containing a cation selected from alkali metals or alkaline earth metals include sodium nitrate, potassium nitrate, magnesium nitrate, strontium nitrate, and the like, with strontium nitrate being particularly preferred. The mixing ratio of the oxidizing agent in the gas generating agent varies in absolute value depending on the type and amount of the gas generating compound used, but is preferably in the range of 40 to 65% by weight, particularly in relation to the above-mentioned CO and NOx concentrations. A range of 45-60% by weight is preferred.

The function of the slag forming agent to be mixed as required is to release an oxide of an alkali metal or an alkaline earth metal generated by the decomposition of the oxidizer component in the gas generating agent to the outside of the inflator as a mist. In order to avoid this, it is a function to change from a liquid state to a solid state and stop it in the combustion chamber, and it is possible to select a slag forming agent optimized by a difference in metal components. Specific examples of the slag forming agent include acid clay, silica, bentonite-based, kaolin-based aluminosilicate-based naturally occurring clay, and synthetic clay such as synthetic mica, synthetic kaolinite, and synthetic smectite. And hydrous magnesium silicate mineral 1
Examples include slag forming agents selected from at least one species such as talc, and among these, acidic clay or silica is preferred, and acidic clay is particularly preferred.

For example, the viscosity and melting point of an oxidized mixture in a ternary system of calcium oxide generated from calcium nitrate, aluminum oxide and silicon oxide, which are main components in clay, are in the range of 1350 ° C. to 1550 ° C. depending on their composition ratios. The viscosity changes from 3.1 poise to about 1000 poise, and the melting point changes from 1350 ° C to 1450 ° C depending on the composition. By utilizing these properties, the slag forming ability corresponding to the mixture composition ratio of the gas generating agent can be exhibited. The mixing ratio of the slag forming agent in the gas generating agent can be changed in the range of 1 to 20% by weight, but is preferably in the range of 3 to 10% by weight. If the amount is too large, the linear burning rate and the gas generation efficiency will decrease. If the amount is too small, the slag forming ability cannot be sufficiently exhibited.

The binder is an essential component for obtaining a desired molded product, and any binder may be used as long as it exhibits viscosity in the presence of water and a solvent and does not have a significant adverse effect on the burning behavior of the composition. It is possible. Specific examples of such binders include metal salts of carboxymethyl cellulose, hydroxyethyl cellulose, cellulose acetate, cellulose propionate, cellulose acetate butyrate, nitrocellulose, and polysaccharide derivatives such as starch. Among them, a water-soluble binder is preferred from the viewpoint of production safety and ease of handling, and a metal salt of carboxymethyl cellulose, particularly a sodium salt, is the most preferred example. The compounding ratio of the binder in the gas generating agent is preferably in the range of 3 to 12% by weight, and more preferably in the range of 4 to 12% by weight. The larger the amount, the stronger the fracture strength of the molded body, but the larger the amount, the greater the number of carbon elements and hydrogen elements in the composition, and a small amount of CO gas, which is an incomplete combustion product of carbon elements Is undesirably increased because the concentration of the gas increases and the quality of the generated gas deteriorates. Particularly, when the amount exceeds 12% by weight, the relative proportion of the oxidizing agent needs to be increased, and the relative proportion of the gas generating compound decreases,
It is difficult to establish a practical gas generator system.

Further, when a sodium salt of carboxymethylcellulose is used as a binder, as a secondary effect, a micro-mixed state of a molecular order of sodium nitrate generated by a metal exchange reaction with a nitrate during the production of a molded body using water. The effect of improving the flammability is to shift the decomposition temperature of nitrate, which is an oxidizing agent, particularly strontium nitrate having a high decomposition temperature, to a lower temperature side.
Preferred gas generating agents used in the practice of the gas generator for airbags of the present invention include: (a) about 25-56% by weight, preferably 30-40% by weight nitroguanidine; (b) about 40-65% by weight; Preferably 45 to 65% by weight of oxidizing agent (c) about 1 to 20% by weight, preferably 3 to 10% by weight of slag former (d) about 3 to 12% by weight, preferably 4 to 12% by weight of binder Particularly preferred compositions include: (a) about 30 to 40% by weight nitroguanidine (b) about 40 to 65% by weight6 strontium nitrate (c) about 3 to 10% by weight A gas generant comprising acid clay or silica and (d) about 4 to 12% by weight of sodium salt of carboxymethylcellulose.

The gas generating agent is desirably formed in a perforated molded body such as a single-hole cylindrical shape or a porous cylindrical shape. Particularly, the value of the inner diameter d of the hole is 0.2 to 1.5 (mm).
When the length is L, the value of L / d is 3.
Desirably, it is 0 or more. This is because when the perforated molded body is ignited by the thermal energy of the ignition system, the ratio of the internal surface area that is initially ignited to the total internal surface area of the inner diameter portion is controlled. The part that is not ignited in the early stage immediately shifts to the ignited state due to the amount of heat generated in the ignited part. Therefore, only the initial ignition stage can be controlled without a time delay until the maximum pressure is reached. It should be recognized that this technique is fundamentally different in this respect from the so-called depower technique in which the overall gas generation output is reduced by a margin and the initial stage is controlled. Therefore, the gas generating agent of the perforated molded body such as the single-hole cylindrical shape or the porous cylindrical shape may be in a single-hole state, or as a result of a small single-hole state aggregate as a result of the control. The shape is not limited as long as the shape can be obtained, but a single hole state is preferable from the viewpoint of molding cost. The value of the inner diameter d of the hole is 0.2
1.51.5 mm, preferably 0.4-1.0 mm. If the value of d is less than 0.2 mm, the initial ignition area of the inner surface of the perforated molding due to the heat energy of the ignition system is insufficient, and the desired result cannot be obtained. , Heat energy reaches the initial ignition combustion area, and a desired gas generation output cannot be obtained. In addition, the value of L / d of the perforated molded product is 3.0 or more. However, if L is too long, the filling efficiency in a desired gas generating container is reduced. It should be determined, the preferred range of the value of L / d is 3.0 to 10.0
It is. If the value of L / d is less than 3.0, the gas generation behavior cannot be controlled as described above. The length L of the porous molded body of the present invention is not particularly limited, but is preferably 1.5 to 30 mm. The outer diameter D is not particularly limited, but is preferably 2.0 to 5.0 mm.

The preferred gas generating agent moldings of the present invention include: (a) about 25-56% by weight nitroguanidine; (b) about 40-65% by weight oxidizing agent; (c) about 1-20% by weight. A composition comprising about 3 to 12% by weight of a binder;
It is formed into a single-hole cylindrical shape.

In the gas generator of the present invention, structures and members advantageous for operating the gas generator can be appropriately adopted. Advantageous structures and members for the operation of the gas generator include, for example, a filter supporting member which is disposed between an inner cylindrical member defining an ignition means accommodating chamber and a filter means and supports the filter means. A "short path prevention means" surrounding the upper end and / or lower end of the inner periphery of the filter means and preventing generated gas from passing through a gap between the filter means and the inner surface of the housing; Or, a "cushion member" disposed below to prevent movement of the gas generating agent, disposed inside the filter means to prevent direct contact between the gas generating agent and the filter means, and furthermore, the filter means A substantially perforated cylindrical "perforated basket" that protects from flames caused by combustion, and a gas passage secured between the outer surface of the filter means and the inner surface of the side wall of the housing. For there is such "gap".

In the gas generator in which a space of a predetermined volume free of the gas generating agent is secured in the combustion chamber as described above, a large-scale structural change is not required, and only the shape of the partition member is devised. Thus, the gas generator is capable of sufficiently restraining the occupant while suppressing the output at the beginning of the operation of the gas generator. According to such a structure, it is advantageous in terms of cost.

The above-described gas generator for an air bag is housed in a module case together with an air bag (bag body) that introduces and inflates the gas generated by the gas generator to form an air bag device.

In this airbag device, the gas generator operates in conjunction with the impact sensor sensing the impact, and discharges the combustion gas from the gas outlet of the housing. This combustion gas flows into the airbag, which breaks the module cover and bulges, forming a shock absorbing cushion between the rigid structure in the vehicle and the occupant.

[0032]

1 to 7 show a preferred embodiment of the gas generator for an air bag according to the present invention.

FIG. 1 is a longitudinal sectional view of one embodiment of the gas generator for an air bag according to the present invention.

The gas generator shown in this figure has a housing 3 comprising a diffuser shell 1 and a closure shell 2.
The inside is defined by an inner cylinder member 16 into two chambers, an ignition means housing chamber 23 and a gas generating agent combustion chamber 28. In the ignition means accommodating chamber 23, ignition means (ignition means including the igniter 4 and the transfer charge 5 in this embodiment) for igniting and burning the gas generating agent 6 by being actuated by an impact is accommodated. In the combustion chamber 28, a gas generating agent 6 that is ignited and burned by the ignition means to generate a combustion gas, the gas generating agent 6 is supported, the movement thereof is prevented, and the inside of the combustion chamber 28 is partitioned. In addition, an annular partition member 110 forming a space portion 100 where no gas generating agent is present is provided. The diffuser shell 1 can be formed by any of casting, forging, press working, and the like. In this embodiment, a stainless steel plate is formed by press working. The diffuser shell 1 is
A circular portion 12 and a peripheral wall portion 10 formed on the outer periphery of the circular portion 12
And a flange portion 19 extending radially outward at the distal end of the peripheral wall portion 10. In the present embodiment, 18 gas outlets 3 each having a diameter of 3 mm are arranged at equal intervals in the circumferential direction on the peripheral wall portion 10, and the gas outlets 11 are closed by a seal tape 52. The diffuser shell 1 is formed with a projecting circular portion 13 protruding outward by a reinforcing step 49 at the center of the circular portion 12, and the reinforcing step 49 is
In particular, the diffuser shell circular part 12 that forms the ceiling
Stiffness and an increase in the volume of the accommodation space. A transfer charge container 53 containing the transfer charge 5 is sandwiched between the projecting circular portion 13 and the igniter 4. The flange portion 19 of the diffuser shell 1 has a mounting portion 98 for mounting the pad module to a mounting bracket. This mounting part 98 is a flange part
19 are arranged at 90-degree intervals in the circumferential direction and have mounting holes 99 for screwing.

The closure shell 2 can be formed by casting, forging, pressing, or the like, similarly to the diffuser shell 1. In this embodiment, a stainless steel plate is pressed and formed. The closure shell 2 has a circular portion 30 and a central hole 15 formed in the center thereof.
And a peripheral wall portion 47 formed on the outer peripheral portion of the circular portion 30, and a flange portion 20 extending radially outward at a distal end portion of the peripheral wall portion 47. The central hole 15 has an axial bent portion 14 at the edge of the hole. The bent portion 14 provides rigidity to the hole edge of the central hole 15 and provides a relatively large joint surface with the inner cylindrical member 16. The inner cylindrical member 16 is arranged so as to fit in the central hole 15. Diffuser shell 1
The flanges 19 and 20 are overlapped with each other near the position on the center cross section in the axial direction of the housing 3, and the two are joined by laser welding 21.
Is formed. These flange portions 19 and 20 provide rigidity to the housing, particularly to the outer peripheral wall 8, and prevent deformation of the housing due to gas pressure.

In this embodiment, a substantially cylindrical inner cylindrical member 16 is provided in the housing, the inside of which is an ignition means accommodating chamber 23, and the outside thereof is a gas generating agent combustion chamber 28. The inner cylindrical member 16 can be formed by any of casting, forging, pressing, cutting, or the like, or a combination thereof. In the case of forming by press working, for example, a UO press system (a plate is formed into a U shape, then formed into an O shape, and a seam is welded), or an electric resistance welded tube system (a plate is formed into a circular shape and a seam is formed) And welding with a resistance current by applying a large current while applying pressure. A caulking portion 27 is formed at an end of the inner cylinder member 16 on the side that houses the igniter 4, and the igniter 4 is fixed by the caulking portion 27. In addition, a combustion chamber
It has a through hole 54 to 28. In the case of this embodiment, the diameter is 2.
Six 5mm through holes 54 are arranged at equal intervals in the circumferential direction,
The through-hole 54 is closed by a seal tape 52 '.
In the present embodiment, a coolant filter 7 disposed in the housing 1 for purifying and cooling gas generated by ignition and combustion of the gas generating agent 6 is disposed so as to surround the gas generating agent 6, An annular chamber, that is, a gas generating agent combustion chamber 28 is defined around the inner cylinder member 16. The coolant / filter 7
Is made by laminating a stainless steel flat knit wire mesh in the radial direction and compressing it in the radial and axial directions. The coolant filter 7 thus formed has a shape in which a loop-shaped stitch is crushed in each layer, which forms a layer in the radial direction. Therefore, this coolant filter 7
In addition to cooling the generated combustion gas, the void structure becomes complicated, so that it can also have an excellent trapping effect. In the present embodiment, further outside the coolant / filter 7,
An outer layer 29 functioning as a suppressing means for suppressing the swelling of the coolant filter is formed. The outer layer 29 is formed by using, for example, a laminated metal net, a porous cylindrical member having a plurality of through holes in a peripheral wall surface, or a belt-shaped restraining layer in which a band member having a predetermined width is formed into an annular shape. You can also. When the outer layer 29 is formed using a laminated metal net, the outer layer 29 can also have a cooling function. Coolant·
The filter 7 cools the combustion gas generated in the gas generant combustion chamber 28 and collects combustion residues. The coolant filter 7 is a circular portion of the closure shell 2.
The movement is prevented by the inclined portion 31 formed in the circumferential direction surrounding the 30, and the gap 9 is reliably formed between the outer peripheral wall 8 of the housing 3 and the coolant filter 7. The gap 9 functions as a gas flow path.

An inner periphery of the coolant / filter 7 protects the filter 7 from a flame caused by the combustion of the gas generating agent, and has a substantially porous cylindrical shape for preventing direct contact between the gas generating agent 6 and the filter 7. A forrated basket 32 is provided.

An electric ignition type ignition means comprising an igniter 4 and a transfer charge 5 is provided in an ignition means accommodating chamber 23 defined inside an inner cylindrical member 16 provided in the housing 3. Are arranged.

In the gas generating agent combustion chamber 28 defined outside the inner cylinder member 16 in the housing, in addition to the gas generating agent 6, the gas generating agent 6 is supported and prevented from moving. A partition member 110 that partitions the inside of the gas generating agent combustion chamber 28 into a gas generating agent accommodating portion 24 and a space portion 100 where no gas generating agent is present.
Are arranged. The gas generating agent combustion chamber 28 includes a gas generating agent storage portion 24 and a space portion 100.
Is preferably less than 18%. The space 100 communicates with the gas generating agent storage unit 24 at least after the start of the combustion of the gas generating agent, and functions to increase the combustion volume of the gas generating agent.

When assembling the gas generator, the partition member 110 stores the gas generating agent in the gas generating agent storage portion 24 and then pushes the gas generating agent 6 in a supporting manner to support the gas generating agent 6.
It is arranged in. Therefore, as shown in FIG. 1, the pressure receiving surface 111 of the partition member 110 that is in contact with the gas generating agent 6 is formed to be flat so that the stored gas generating agent 6 can be evenly supported. It is desirable that the circumference 112 and the outer circumference 113 are bent in the direction in which the space 100 is formed, that is, toward the closure shell 2 side. This partition member 110 allows the gas generating agent 6
Since the gas generating agent is supported, the movement of the gas generating agent is prevented, the gas generating agent is broken by vibration, and the possibility of changing the surface area can be eliminated.

As the partition member 110, in addition to FIG. 1, FIG.
As shown in (b), the contact surface with the gas generating agent, that is, the pressure receiving surface 1
An appropriate large hole 114 is formed in 11, and the hole 114 is closed with a sheet member 115 that ruptures due to pressure at the time of combustion of a gas generating agent such as metal, plastic or paper, and the closed portion is a fragile portion. It can be formed as 116. FIG. 2A shows a partition member formed by casting or the like, and FIG. 2B shows a partition member formed by press working. When formed by press working like the partition member shown in FIG. 2 (b), it is advantageous in cost. The fragile portion 116 formed in this way is
Destroyed (or ruptured) by combustion of the gas generant,
In FIG. 1, the gas generating agent accommodating section 24 communicates with the space section 100,
Increase the combustion volume of the gas generant. This sheet member
The closing of the hole 114 by the hole 115 can be performed from either the upper part or the lower part of the hole 114. In addition to attaching the sheet member 115, the sheet member 115 is separated from the partition member 110 and the gas generating agent 6
It is also possible to pinch it between. The shape of the hole 114 may be substantially fan-shaped as shown in FIGS. 2A and 2B, or a plurality of substantially circular holes 117 may be formed as shown in FIG. The inner periphery 112 of the partition member shown in FIG. 3 is bent into a wall shape, the inner periphery 118 can clamp the inner cylinder member 16 and can be fixed at a predetermined position in the housing.

The partition member communicates the gas generating agent accommodating portion 24 with the space 100 defined by the partition member at least at any time when the gas generating agent burns, and the combustion volume of the gas generating agent is Function to increase the The partition member having such a function can be further formed in an embodiment shown in FIGS. 4 to 7 in addition to the embodiment shown in FIGS.

The partition member 120 of the embodiment shown in FIG.
On the pressure receiving portion 121, a slit 123 which is notched in a fan shape leaving the direction of the inner periphery 122 is formed. The shape of the slit 123 is not only a sector shape but also a portion 124 surrounded by the slit.
However, it can be appropriately shaped so as to bend in the direction of the space. In this embodiment, due to the combustion of the gas generating agent, the portion 124 surrounded by the slit 123 is bent and substantially expanded toward the space as shown in FIG.
Part of 0 (in this embodiment, part surrounded by slits)
Is deformed. As a result, in FIG. 1, the gas generating agent accommodating portion 24 and the space communicate with each other to increase the combustion volume of the gas generating agent. In the partition member 120 shown in FIGS. 4 (a) and 4 (b), the outer periphery 125 is bent into a wall shape, and can be fitted into, for example, the inner surface of a coolant / filter and fixed at a predetermined position in the housing. The aspect of the partition member 130 whose overall shape can be changed by the combustion of the gas generating agent 6 is shown. That is, the partition member 130 in this embodiment is the gas generating agent accommodation chamber 24.
The material, the shape and the thickness, which have a deformable strength, such as crushing by the pressure of the gas generating agent 6 during combustion, supporting the gas generating agent 6 disposed therein, It is formed after being appropriately selected. As a result, the partition member 130 is moved by the combustion of the gas generating agent 6.
The entire 30 is deformed, and the combustion volume of the gas generating agent can be increased.

The partition member 140 of the embodiment shown in FIG. 6 forms a notch groove on the back side of the pressure receiving surface 141 of the partition member to such an extent that the notch groove is cut by the combustion of the gas generating agent 6, and the notch groove is made fragile. The part 142 is cut by the combustion of the gas generating agent. Due to the cutting of the fragile part, the pressure receiving part moves in the direction indicated by the arrow in the figure, and the gas generating agent storage part 24 and the space
Communicate with 100. As a result, it is possible to increase the volume of the gas generating agent storage section 24 by burning the gas generating agent 6. The formation on the fragile portion 142 is not limited to the back side of the pressure receiving portion 141, and may be formed on the front side of the pressure receiving portion 141, or on the bent leg portion 143 on the inner or outer circumference. The fragile portion 142 is cut by the burning of the gas generating agent 6, and can be formed in an appropriate shape as long as the burning volume of the gas generating agent can be increased as a result.

In the embodiment of the partitioning member shown in FIG. 7, the partitioning member 150 is displaced (moved) in the direction shown by the arrow in the drawing due to the combustion of the gas generating agent 6, and the volume of the gas generating agent accommodating portion 24 is increased. Things. That is, in this embodiment, the partition member 150 is fixed by press-fitting the end portion 151 into the inner cylindrical member, and supports the gas generating agent 6. Then, due to the combustion of the gas generating agent 6, the partition member 150 is pushed down toward the space 100, that is, in the direction indicated by the arrow in the drawing, and as a result, the volume of the gas generating agent accommodating portion 24 is increased. Therefore, in this embodiment, the partition member 150 is securely fixed when the gas generator is not operating, and the partition member 150 is displaceable (movable) by the combustion of the gas generating agent 6. The degree of fixation needs to be adjusted.

In view of the fact that the volume of the gas generating agent accommodating chamber 24 is increased by the combustion of the gas generating agent, the above-mentioned partition member may be, for example, a partition other than that described with reference to FIGS. It is also possible to form the member using a material (for example, paper) which easily burns, and to burn the partition member by burning the gas generating agent.

FIG. 8 shows an example of an air bag gas generator formed without defining an ignition means accommodating chamber in the housing 303.

The gas generator shown in this figure has a housing 30 comprising a diffuser shell 301 and a closure shell 302.
3, an igniter 304 disposed in a housing space in the housing 303, a solid gas generating agent 306 that is ignited by the igniter 304 to generate a combustion gas, and a combustion chamber that stores the gas generating agent 306. Coolant filter 307 defining 328;
The coolant filter 307 and the housing 3
03 and a gap 309 formed between the outer peripheral walls 310.

The diffuser shell 301 is formed by pressing a stainless steel plate by pressing.
It has a plurality of radial ribs 379 arranged radially. These ribs 379 are diffuser shell 301
The circular portion 312 is provided with rigidity, thereby preventing the circular portion 312 forming the ceiling portion of the housing from being deformed by gas pressure.

The closure shell 302 is formed by pressing a stainless steel plate by pressing, and a concave portion 373 is formed in the center of the circular portion 330. A central hole 37 is formed in the central portion of the concave portion 373.
4 are formed. The central hole 374 has an axial bent portion 375 at the edge of the hole, and an end surface 383 for engaging the igniter 304 is formed at the tip of the bent portion 375. Due to the inner circumference of the axially bent portion 375, a relatively large seal surface is secured between the igniter 304 and the igniter 304. To ensure airtightness, the igniter 304
A sealant can be filled between the igniter 304 and the end face 383. The end surface 383 on which the igniter 304 is locked prevents the igniter 304 from coming out due to the gas pressure in the combustion chamber 328.
The concave portion 373 provides rigidity to the circular portion 330 of the closure shell, and has the bottom surface of the igniter 304 at a position inside the outer surface of the circular portion 330.

The front end of the diffuser shell 301 has a flange portion 386 extending radially outward, and the front end of the closure shell 302 is also formed with a flange portion 387 extending radially outward. These flanges 386, 38
Laser welding is carried out by superimposing 7 at a substantially axial center position of the housing, and the two shells are joined to each other. These flange portions 386 and 387 provide rigidity to the outer peripheral wall of the housing, and prevent deformation of the housing due to gas pressure.

The igniter 304 comprises a conventional electric igniter which is activated by a signal from a sensor (not shown). This electric igniter 304 (output: 300 to 1500 psi in a 10 cc sealed pressure vessel) has a simple structure, does not include a mechanical mechanism, and is small and lightweight.

The coolant filter 307 is arranged concentrically with the central hole 374 and, together with the housing 303, defines a combustion chamber 328. This coolant filter 307 is formed by stacking stainless steel flat knit wire meshes in the radial direction and compressing them in the radial and axial directions. The coolant filter 307 defines a combustion chamber 328, cools the combustion gas generated in the combustion chamber, and collects combustion residues. An outer layer 329 made of a laminated metal mesh is formed outside the coolant / filter 307. This outer layer 329 serves both for reinforcing the coolant filter and for cooling the gas.

The interior of the combustion chamber 328 is defined by a partition member 160 into a gas generating agent storage section 324 and a space section 100. The gas generating agent 306 is filled in the gas generating agent accommodating portion 324, and is filled in the gas generating agent accommodating portion 324 adjacent to the igniter 304, and a plate member closing one side end opening of the coolant filter 307 is provided. The movement is restricted by the circular portion 392. The plate member 391 has the circular portion 392 and a peripheral wall portion 393 integral with the circular portion 392, which abuts on the inner peripheral surface of one end of the coolant filter 307 to cover the inner peripheral surface. I have. The plate member 391 prevents a short path of the combustion gas between the end face of the coolant filter and the inner face of the circular portion 312 of the diffuser shell.

The partition member 160 includes a coolant / filter 307
And the axially bent portion 375, and the inner and outer bent portions 161 and 162 of the partition member 160 are fixed by spreading. The partition member 160 has the above-described weak portion, and the space 100 defined by the partition member 160 communicates with the gas generating agent storage portion 324 when the gas generating agent is burned,
Functions as a gas generant combustion chamber.

The inner wall surface of the housing 303 and the coolant
A gap 309 is formed between the filter 307 and the outer layer 329, and the gap 309 forms a gas passage having a circular cross section in the radial direction around the coolant / filter 307. The gas outlet 311 of the housing 303 is closed by a seal tape 352.

The gas generator for an airbag shown in FIG. 9 is an example of a gas generator for an airbag in which the interior of the housing 303 is not divided into two chambers, as in the gas generator shown in FIG. Show. However, in the gas generator shown in FIG. 9, the arrangement of the partition member 170 is different from the gas generator shown in FIG.

That is, in the gas generator shown in this figure, the partition member 170 is disposed on the end of the peripheral wall of the igniter 304 mounted on the end surface 383 of the bent portion 375 in the axial direction. Therefore, the partition member 170 is formed in a flat plate shape. The partition member 170 also has the weak portion, and the space 100 defined by the partition member 170 also communicates with the gas generating agent storage portion 324 when the gas generating agent is burned, and the gas generating agent combustion chamber Function as

In the gas generator shown in FIG. 9, the same members as those described with reference to FIG. 8 are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 10 shows an embodiment of the airbag apparatus of the present invention in the case of including a gas generator using an electric ignition type ignition means.

This airbag device is composed of a gas generator 200
, An impact sensor 201, a control unit 202, a module case 203, and an airbag 204. As the gas generator 200, the gas generator described with reference to FIG. 1 is used, and its operation performance is adjusted in the initial stage of the gas generator operation so as to minimize impact on the occupant. ing.

The impact sensor 201 can be composed of, for example, a semiconductor acceleration sensor. In this semiconductor type acceleration sensor, four semiconductor strain gauges are formed on a beam of a silicon substrate which is deflected when acceleration is applied,
These semiconductor strain gauges are bridge-connected.
When acceleration is applied, the beam deflects, causing strain on the surface. Due to this strain, the resistance of the semiconductor strain gauge changes, and the change in resistance is detected as a voltage signal proportional to the acceleration.

The control unit 202 has an ignition determination circuit, and a signal from the semiconductor acceleration sensor is input to the ignition determination circuit. When the shock signal from the sensor 201 exceeds a certain value, the control unit 202 starts the calculation, and when the calculation result exceeds a certain value, outputs an operation signal to the igniter 4 of the gas generator 200.

The module case 203 is made of, for example, polyurethane, and includes a module cover 205. The module case 203 houses the airbag 204 and the gas generator 200 and is configured as a pad module. When the pad module is mounted on the driver's seat side of an automobile, the pad module is usually mounted on the steering wheel 207.

The airbag 204 is formed of nylon (eg, nylon 66) or polyester, and its bag opening 206 surrounds the gas outlet of the gas generator and is fixed to the flange of the gas generator in a folded state. Have been.

When a semiconductor type acceleration sensor 201 detects a shock at the time of a car collision, the signal is sent to the control unit 202, and when the shock signal from the sensor exceeds a certain value, the control unit 202 starts calculation.
When the calculated result exceeds a certain value, an operation signal is output to the igniter 4 of the gas generator 200. Thereby, the igniter 4 operates to ignite the gas generating agent, and the gas generating agent burns to generate gas. This gas is blown into the airbag 204, whereby the airbag breaks the module cover 205 and bulges, forming a cushion between the steering wheel 207 and the occupant to absorb impact.

[0067]

The gas generator for an air bag according to the present invention operates by applying as little impact as possible to the occupant in the initial stage of operation, and then rapidly inflates the air bag. Provided is a gas generator for an airbag having a simple structure capable of reliably protecting an occupant.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a gas generator according to one embodiment of the present invention.

FIG. 2 is a perspective view showing a partition member in FIG.

FIG. 3 is a perspective view showing another form of the partition member.

FIG. 4 is a perspective view showing still another embodiment of the partition member.

FIG. 5 is a vertical sectional view of a main part showing still another embodiment of the partition member.

FIG. 6 is a vertical sectional view of a main part showing still another embodiment of the partition member.

FIG. 7 is a vertical sectional view of a main part showing still another embodiment of the partition member.

FIG. 8 is a longitudinal sectional view showing a gas generator according to another embodiment of the present invention.

FIG. 9 is a longitudinal sectional view showing a gas generator according to still another embodiment of the present invention.

FIG. 10 is a configuration diagram of an airbag device of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 3 housing 4 igniter 5 transfer agent 6 gas generating agent 7 coolant / filter 12, 30 circular portion 24 gas generating agent storage location 28 gas generating agent combustion chamber 100 space 110, 120, 130, 140, 150, 160, 170 partition member

Claims (12)

[Claims] 1. A housing having a gas discharge port and containing a single ignition means operated by impact and a gas generating agent which is ignited by the ignition means and burns to generate combustion gas. A gas generator for an air bag, wherein a combustion chamber in which a gas generating agent is burned is provided in the housing, and a space in which a predetermined volume of the gas generating agent does not exist is secured in the combustion chamber, and gas generation is performed. A gas generator for an air bag, wherein the combustion volume of the gas generating agent is expanded to the space when the agent is ignited and burned. 2. A gas generator for an airbag according to claim 1, wherein said space is secured by partitioning said combustion chamber with a partition member. 3. The partitioning member has a pressure receiving surface for supporting the gas generating agent, and the pressure receiving surface contacts the gas generating agent to support and fix the gas generating agent. Gas generator for airbags. 4. The airbag according to claim 2, wherein the partition member is deformed and / or displaced and / or destroyed by combustion of the gas generating agent, and expands the combustion volume of the gas generating agent to the space. For gas generator. 5. The partition member has a fragile portion on its pressure receiving surface which is destroyed by burning of the gas generating agent, and the fragile portion is deformed and / or broken to reduce the combustion volume of the gas generating agent. 4. The gas generator for an airbag according to claim 2, wherein the gas generator extends to a space. 6. A sheet member for closing an upper and / or lower portion of a hole provided in a pressure receiving surface of the partition member, wherein the sheet member is ruptured by combustion of a gas generating agent. A gas generator for an airbag as described in the above. 7. The airbag according to claim 5, wherein the fragile portion is a notch groove provided on a front surface or a back surface of the pressure receiving surface of the partition member, and the notch groove is cut by combustion of a gas generating agent. Gas generator. 8. The gas generator for an airbag according to claim 2, wherein a part or all of the partition member is deformed to expand the combustion volume of the gas generating agent to the space. 9. The partition member is fixed in the combustion chamber, and the partition member moves by burning the gas generating agent, thereby expanding the combustion volume of the gas generating agent to the space. The gas generator for an airbag according to claim 2. 10. The gas generator for an airbag according to claim 1, wherein the gas generating agent is a non-azide gas generating agent. 11. The gas generator for an air bag according to claim 1, wherein the gas generating agent has a single-hole cylindrical shape or a multi-hole cylindrical shape. 12. A gas generator for an airbag, an impact sensor that detects an impact to operate the gas generator, an airbag that introduces gas generated by the gas generator and expands, and the airbag. And a module case for accommodating the
An airbag device, wherein the gas generator for an airbag is the gas generator for an airbag according to any one of claims 1 to 11.