JPH11189125A - 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 giving the least possible shock to an occupant in the initial stage of operation and then rapidly increasing gas pressure so as to positively protect the occupant. SOLUTION: A single ignition means actuated by impact, and gas generating agents 6 ignited by the ignition means to burn and generate combustion gas are accommodated in a housing 3 with a gas exhaust port to constitute a gas generator for an air bag. The ignition means is constituted comprising transfer change 5 for igniting the gas generating agents 6 to burn. A first passage 34 where combustion gas generated by combustion of the transfer change 5 passes without passing through a gas generating agent storage part, and a second passage 35 where combustion gas of the gas generating agents 6 burned by the combustion gas of the transfer change 5 passes, are formed in the housing 3.

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, the occupant is prevented from smashing into a hard part inside the vehicle, such as a steering wheel or a front glass, due to inertia 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, or an adult or a child) or his riding posture (for example, a posture that clings 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.

In Japanese Patent Application Laid-Open No. 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. Nos. 4,998,751 and 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]

SUMMARY OF THE INVENTION A gas generator for an air bag according to the present invention has a single ignition means operated by impact in a housing having a gas discharge port, and is ignited by the ignition means to burn and burn combustion gas. In a gas generator for an airbag containing a gas generating agent containing the generated gas, the gas discharge port is closed by a seal tape, and the seal tape bursts at an early stage of the gas generator operation. With the structure described later, the impact on the occupant in the early stage of bag deployment can be suppressed, and the above object can be achieved.

As a gas generator for rupture of the sealing tape in the early stage of the operation of the gas generator, for example, a gas is generated in two stages by the internal structure of the gas generator, and the sealing tape is used in the early stage of the operation of the gas generator. If ruptured,
Specifically, when the first-stage combustion gas is generated at an early stage of the gas generator operation, and the seal tape is ruptured by the combustion gas, and then the second-stage gas is discharged from the gas outlet, Due to the rupture of the seal tape in the early stage of the gas generator operation, the operation performance of the gas generator is, as described above,
In the early stages of operation of the gas generator, the operation can be performed with as little impact on the occupant as possible, and can be adjusted in a subsequent operation stage to ensure protection of the occupant.

The gas generator for an air bag which generates gas in two stages as described above has an ignition means activated by an impact in a housing having a gas discharge port, and is ignited by the ignition means to burn and burn the combustion gas. A gas generator for an airbag containing and containing a generated gas generating agent, wherein the igniting means is configured to include a transfer charge for igniting and burning the gas generating agent, and wherein A first passage through which a combustion gas generated by combustion of the transfer agent passes without passing through the gas generating agent storage section, and a second passage through which the combustion gas of the gas generating agent burned by the combustion gas of the transfer agent passes. It can also be realized by a gas generator for an airbag in which two flow paths are formed.

[0010] In such a gas generator, a bypass for discharging the combustion gas of the transfer charge to the outside of the housing as it is is formed, and the bypass is used as a first flow path and passes through the first flow path. If the combustion gas is to reach the seal tape (ie, the gas outlet) quickly, the seal gas may be ruptured at an early stage of gas generator operation by the combustion gas passing through the first flow path. Can be. The second flow path is a flow path of the combustion gas of the gas generating agent ignited by the combustion gas of the transfer charge that does not pass through the first flow path, and the combustion gas sufficiently passes through the airbag (bag). Inflate to. At this time, a larger amount of gas is released than the amount of gas previously released to the outside of the gas generator through the first flow path. The combustion gas passing through the second flow path is discharged following the combustion gas discharged through the first flow path. With such a structure, it is possible to prevent an excessive impact from being applied to the occupant in the early stage of the gas generator operation.

The first and second flow paths are formed, for example, by disposing an inner cylinder member in a housing, the inner side thereof being an ignition means housing chamber, and the outer side thereof being a combustion chamber for a gas generating agent. When the igniting means provided in the igniting means accommodating chamber includes a transfer agent for igniting and burning a gas generating agent to constitute a gas generator for an air bag, the igniting means is provided in a circumferential direction of the inner cylindrical member. The through-hole array is formed on horizontal planes of different heights, and the through-hole array formed on any one of the horizontal planes (preferably, the through-hole array formed on the horizontal plane on the diffuser shell side) includes:
In order to guide the gas generated by the combustion of the transfer charge discharged from the through-hole row to the filter means or the like without passing through the gas generating agent accommodating section, the combustion chamber is partitioned by a partition plate and the first flow path is formed. The first flow path can be secured by defining or by providing a pipe-shaped thing connected to the row of through holes. In addition, it is also possible to provide an opening at a predetermined position of the housing corresponding to the transfer charge accommodating place in the ignition means storage chamber, and to discharge the gas generated by combustion of the transfer charge from the opening as it is. In this case, the opening is desirably closed with a seal tape.

The gas generator for an air bag according to the present invention is
In a housing having a gas discharge port, an ignition means operated by an impact, and a gas generating agent which is ignited by the ignition means and burns to generate a combustion gas are contained and housed.
Further, if necessary, in the housing,
Filter means for cooling the combustion gases and / or collecting combustion residues are also accommodated.

The housing having the gas discharge port can be formed by casting, forging, pressing, or the like. Desirably, 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 thereof is facilitated. 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.

The single ignition means operated by the above-mentioned impact preferably uses an electric ignition type ignition means operated 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 exclusively 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 is bent 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, the signal from the semiconductor acceleration sensor is input to the 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 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. As such a material, for example, in addition to using a conventionally used filter for purifying generated gas and / or a coolant for cooling generated gas, 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 or forming a flat knitted stainless steel wire mesh in a cylindrical body, pressing this cylindrical body in the radial direction to form a plate, and winding the plate in a cylindrical shape multiple times 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 of 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 net, 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 two or more selected from the group consisting of a tetrazole derivative and a guanidine derivative are preferable, and in particular, nitroguanidine,
Preferred are cyanoguanidine and 5-aminotetrazole, and most preferred is nitroguanidine because of the small number of carbon atoms in the molecule. Nitroguanidine includes needle-like crystalline nitroguanidine having a low specific gravity and nitroguanidine having a high specific gravity of bulk crystals.Either of them can be used.However, in terms of safety and easy handling during the production in the presence of a small amount of water, high nitroguanidine is required. The use of specific gravity nitroguanidine is preferred. The compounding ratio of this 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.

Although the absolute value of the compounding ratio of the nitrogen-containing compound varies depending on the type of the oxidizing agent in the gas generating agent, if the amount exceeds the theoretical amount of complete oxidation, the concentration of trace CO in the generated gas increases, and the theoretical amount of complete oxidation and 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, but an oxidizing agent selected from at least one nitrate 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 added as required is that the oxide of the alkali metal or alkaline earth metal generated by the decomposition of the oxidizer component in the gas generating agent is discharged as a mist to the outside of the inflator. 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 clays and synthetic clays such as synthetic mica, synthetic kaolinite, and synthetic smectite. And hydrous magnesium silicate mineral 1
Examples thereof include slag forming agents selected from at least one species such as talc, among which 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 as 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. Any binder can be used as long as it exhibits viscosity in the presence of water, a solvent, and the like, and does not significantly affect the combustion behavior of the composition. It is possible. Specific examples of the binder 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, 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 above gas generating agent can be used in various shapes such as a single-hole cylindrical shape or a porous cylindrical shape, a pellet shape, a disk shape and the like. In particular, it is desirably formed in a perforated molded body such as a single-hole cylindrical shape or a porous cylindrical shape. In particular, the perforated molding has a value of the inner diameter d of the hole of 0.2 to 1.5.
(Mm), and when the length is L, the value of L / d is desirably 3.0 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 to 1.5 mm, preferably 0.4 to 1.0 mm.
If the value of d is less than 0.2 mm, the initial ignition area on the inner surface of the perforated molding due to the thermal 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 is to be determined that the preferred range of the value of L / d is between 3.0 and 0.1.
It is 0. 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 to 56% by weight of nitroguanidine; (b) about 40 to 65% by weight of an oxidizing agent; (c) about 1 to 20% by weight of A composition comprising about 3 to 12% by weight of a binder;
It is formed into a single-hole cylindrical shape.

[0027] In the gas generator of the present invention, advantageous structures and members can be appropriately employed for the operation of the gas generator. As a structure / member advantageous for the operation of the gas generator, for example, a filter supporting member which is disposed between an inner cylinder member defining an ignition means accommodating chamber inside and a filter means and supports the filter means is provided. 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".

The gas generator for an air bag described above is housed in a module case together with an air bag (bag) that expands by introducing the gas generated by the gas generator, thereby forming 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 exhaust port 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.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the gas generator for an air bag according to the present invention as described above will be described with reference to the drawings.

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

In the gas generator shown in this embodiment, the inside of the housing 3 composed of the diffuser shell 1 and the closure shell 2 is formed by the inner cylinder member 16 into the ignition means accommodating chamber 23.
A gas generating agent combustion chamber 28 is defined. An ignition means for igniting and burning the gas generating agent 6 by an impact is accommodated in the ignition means accommodating chamber 23, and a combustion gas is ignited and burned by the ignition means in the combustion chamber 28. A gas generating agent 6 is provided. In this embodiment, the ignition means comprises an igniter 4 and a transfer charge 5.

The gas generator shown in FIG. 3 forms the ignition means including a transfer charge 5 for igniting and burning a gas generating agent 6, and the combustion of the transfer charge 5 in the housing 3. First passage through which the combustion gas generated by
And a second flow path 35 through which the combustion gas generated from the gas generating agent 6 ignited and burned by the combustion of the transfer charge passes.
To form The combustion gas passing through the first flow path 34 is
The gas generating agent 6 is discharged without being ignited or burned. Therefore, the gas passing through the first flow path 34 quickly reaches the gas outlet 11 (at the initial stage of the gas generator operation), and ruptures the sealing tape 52 that closes the gas outlet 11. It is discharged out of the housing 3.

In the present embodiment, a known charge is used as the transfer charge 5, a gas generating agent 6 is mixed with the transfer charge 5, or the transfer charge 5 is entirely gaseous. It can be used in place of the generator 6.
In this case, the gas generating agent that is replaced as a transfer charge is
The combustion gas passes through the first flow path and seals the gas outlet 11 at an early stage of the gas generator operation.
At the point of exploding 52, the gas generating agent
It is distinguished from the gas generating agent 6 housed therein.

The gas generating agent 6 is solid and is contained in the gas generating agent combustion chamber 28. In this embodiment, the gas generating agent is a non-azide gas generating agent, in particular, a solid gas generating agent composed of nitroguanidine, Sr (NO ₃ ) ₂ , carboxymethyl cellulose and acid clay, A gas generating agent having a composition weight ratio of nitroguanidine: Sr (NO ₃ ) ₂ : carboxymethylcellulose: acid clay = 35.4: 49.6: 10: 5, and nitroguanidine, Sr (NO ₃ ) ₂ , sodium carboxymethylcellulose It consists of salt and acid clay, and its composition weight ratio is nitroguanidine: Sr
(NO ₃ ) ₂ : a sodium salt of carboxymethyl cellulose: acid clay = 31.5: 51.5: 10: 7 can be used as a gas generating agent. The gas generating agent 6 is in the form of a hollow cylinder, and the length of one gas generating agent is L (m
m), when the inner diameter of the hole of the molded body is d (mm), the value of d is 0.2
It is regulated to 1.5 (mm) and the value of L / d is 3.0 or more. Due to this shape, the combustion takes place on the outer and inner surfaces, with the advantage that the surface area of the entire gas generant does not change much as the combustion proceeds. However, in the present invention, the gas generating agent can be used in other shapes, for example, various shapes such as a pellet shape and a disk shape. This is because, in the gas generator of the present invention, two flow paths are formed, and the combustion gas passing through the first flow path breaks the seal tape 52 in the initial stage of the gas generator operation and a small amount of gas is supplied to the housing. Since the gas generating agent 6 is discharged outside and then discharges a large amount of combustion gas passing through the second flow path, the effects of the present invention can be obtained even if the gas generating agent 6 has a shape other than a hollow cylindrical shape. That's why.

The diffuser shell 1 can be formed by any of casting, forging, pressing and the like. In this embodiment, a stainless steel plate is formed by pressing. The diffuser shell 1
Is a circular portion 12, and a peripheral wall portion formed on the outer periphery of the circular portion 12.
10 and a flange 19 extending radially outward at the tip of the peripheral wall 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 has a circular projection 12 formed at the center of the circular section 12 by a reinforcing step 49 so as to protrude outward. The reinforcing step 49 is formed of the housing 3, especially a diffuser shell forming its ceiling. The rigidity is given to the circular portion 12, and the volume of the accommodation space is increased. 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 portion 98 is disposed at 90 ° intervals in the circumferential direction of the flange portion 19,
It has a mounting hole 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 the present embodiment, ignition of the gas generating agent 6
A coolant filter 7 disposed in the housing 1 for purifying and cooling gas generated by combustion is disposed so as to surround the gas generating agent 6, and an annular chamber around the inner cylinder member 16, ie, an annular chamber, A gas generant combustion chamber 28 is defined. The coolant filter 7 is formed by laminating stainless steel flat knit wire meshes in the radial direction and compressing them 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, the coolant / filter 7 not only cools the generated combustion gas, but also has an excellent trapping effect because the void structure becomes complicated. However, the coolant filter 7 can be omitted if the gas generating agent used does not generate combustion residues.

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. Further, a combustion chamber is provided on the peripheral wall of the inner cylindrical member 16.
A plurality of through-holes 54 to 28 are arranged in the circumferential direction to form a row of through-holes. In the case of the gas generator shown in FIG.
Upper and lower rows of through-holes, each having six 2.5 mm through-holes 54 arranged at equal intervals in the circumferential direction, are formed, and each through-hole 54 is closed by a seal tape 52 '.

In the present embodiment, the first flow path 34 is formed as a bypass which functions to discharge the gas generated by the combustion of the transfer charge 5 to the outside of the housing 3 as it is. As shown in FIG. 1, an inner cylindrical member 16 having a row of through holes 54 in a peripheral wall portion present on planes having different heights is disposed in the housing 3, and the inner side thereof is disposed inside the ignition means accommodating chamber 2.
3. A combustion chamber 28 for the gas generating agent 6 is provided on the outside, and an ignition means including a transfer charge 5 for igniting and burning the gas generating agent 6 is provided in the ignition means accommodating chamber to provide a gas generator for an air bag. In the case of the configuration, the bypass (first flow path 34) is provided on any one of the horizontal planes (in FIG. 1, the horizontal plane on the diffuser shell 1 side) in the row of through holes on different horizontal planes of the inner cylindrical member. Up)
The combustion gas of the transfer charge 5 discharged from the through-hole row 54 ′ formed in the combustion chamber 28 is guided to the coolant / filter 7 as it is without burning the gas generating agent 6. Can be partitioned by a partition plate 36 to form the first flow path 34.

As for the formation of the first flow path, as shown in FIG. 2, the combustion gas of the transfer charge 5 discharged from the row of the through holes 54 formed on any one of the horizontal planes is also used. ,
Several pipes 37 may be formed integrally with the inner cylindrical member 16 in a radial manner to directly guide the coolant / filter 7 to the coolant / filter 7, and the hollow inside the pipes 37 may be used as the first flow path 34.

As shown in FIG. 3, the number of through-holes formed in the inner cylindrical member 16 defining the combustion chamber 28 and the ignition means accommodating chamber 23 in the housing is substantially one in the horizontal direction (staggered). In the housing, in the housing of the ignition means
An opening 38 is provided in the area corresponding to the place where
It is also possible to directly discharge the combustion gas generated by the combustion of the transfer charge 5 from the opening 38. In this case, it is desirable that the opening 38 be closed with a sealing tape 52 ".

In the gas generator for an air bag shown in FIGS. 1 to 3, the second flow path 35 is a flow path of a combustion gas generated by the combustion of the gas generating agent 6, Is discharged from a through-hole 54 formed in the inner cylindrical member 16 in a range in which the inside is the ignition means housing chamber 23 and the outside is the combustion chamber 28. The combustion gas generated by the combustion of the gas generating agent 6 is cooled and purified by the coolant / filter 7 and discharged from the gas outlet 11.

In the embodiment shown in FIG. 1 or 2, the combustion gas of the transfer charge 5 passing through the first flow path 34 is the combustion gas of the gas generating agent 6 passing through the second flow path 35. It reaches the sealing tape 52 (that is, the gas discharge port 11) earlier, and ruptures the sealing tape 52 at an early stage of the gas generator operation. After that, the combustion gas of the gas generating agent 6 ignited and burned by the flame of the transfer charge 5 passing through the second flow path 35 reaches the gas outlet 11 and is discharged from the housing 3 through the outlet 11. A gas generator that discharges gas in two stages.

In the early stage of the operation, an airbag gas generator is provided which operates with as little impact on the occupant as possible and can surely protect the occupant in a subsequent operation stage. As a result, the gas generator for an airbag shown in these examples does not need to intentionally suppress ignition and combustion of the gas generating agent, and it is not necessary to limit the shape of the gas generating agent to a single-hole cylindrical shape or the like. It can be used in the form of a disk, disk, etc., but it operates with as little impact on the occupant as possible at the initial stage of operation, and reliably protects the occupant in the subsequent operation stage. It becomes a gas generator for an airbag showing the obtained operation performance.

In the present embodiment, the coolant / filter 7 is further provided outside the coolant / filter 7 so that the coolant / filter 7 does not bulge due to gas pressure when the gas generator is operated and does not close the gap 9. An outer layer 29 functioning as a suppressing means for suppressing bulging is formed. The outer layer 29 is formed using, for example, a laminated metal net, a porous cylindrical member having a plurality of through holes in the 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 filter 7 allows gas generating agent combustion chamber
The combustion gases generated in 28 are cooled and combustion residues are collected. The coolant / filter 7 is prevented from moving by an inclined portion 31 formed in the circumferential direction surrounding the circular portion 30 of the closure shell 2, so that the coolant / filter 7 is securely located between the outer peripheral wall 8 of the housing 3 and the coolant / filter 7. Gap 9
Is formed. The gap 9 functions as a gas flow path.

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

An electric ignition type ignition means including 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.

2 and 3 showing the present embodiment, the same members as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 4 shows an embodiment of the airbag apparatus of the present invention in the case of including a gas generator using electric ignition type ignition means.

This airbag apparatus is provided with 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 shock 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 bent when an 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 (for example, nylon 66) or polyester, and its bag port 206 surrounds the gas discharge port of the gas generator, and is fixed to the flange of the gas generator in a folded state. Have been.

When an impact is detected by the semiconductor acceleration sensor 201 at the time of a vehicle collision, a signal is sent to the control unit 202, and when the impact 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 blows out into the airbag 204, which breaks the module cover 205 and bulges out, forming a cushion between the steering wheel 207 and the occupant to absorb impact.

[0057]

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 an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a gas generator according to another embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing a gas generator according to still another embodiment of the present invention.

FIG. 4 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 34 first flow path 35 second flow path

Claims (4)

[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. An airbag gas generator, wherein the ignition means includes a transfer charge for igniting and burning a gas generating agent, and a combustion gas generated by combustion of the transfer charge is generated in the housing. A first flow path that passes without passing through the agent storage section, and a second flow path through which the combustion gas of the gas generating agent burned by the combustion gas of the transfer agent passes. Gas generator for airbags. 2. The first flow path is a bypass for discharging the combustion gas of the transfer charge to the outside of the housing as it is,
The combustion gas of the transfer charge passing through the first flow path is discharged out of the housing earlier than the combustion gas of the gas generating agent discharged through the second flow path. Gas generator for airbags. 3. The gas generator for an air bag according to claim 1, wherein the gas generating agent is a non-azide gas generating agent. 4. A gas generator for an air bag, an impact sensor that senses an impact to activate the gas generator, an air bag that inflates by introducing gas generated by the gas generator, and the air bag. And a module case for accommodating the
The gas generator for an airbag according to any one of claims 1 to 3,
An airbag device, characterized in that it is a gas generator for an airbag according to any one of the preceding claims.