JPH10203298A - Gas generator for air bag and air bag device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deformation of a housing peripheral wall surface by limiting projection of welding burr generated by friction welding of a diffuser shell and a closure shell into a housing by a welding burr limiting member which is abutted within the housing for the joining part of both the shells. SOLUTION: In a gas generator housing, welding burr 23 projecting by friction welding of a diffuser shell 2 having a gas exhaust port 4 and a closure shell 3 clogging the diffuser shell 2 is supported by a coolant filter 15 so as not to project within a housing. Even if the projecting of the welding burr 23 within the housing is limited by the coolant filter 15, a reinforcing part 30 whose thickness is increased is formed in a module mounting part 31 provided on the diffuser shell 2 so that the housing peripheral surface may not swell outward.

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 device used for reducing the impact on an occupant in a vehicle collision, and more particularly, to a gas generator having a housing for the same.
The present invention relates to a housing structure of a gas generator for an airbag in which a diffuser shell having a gas discharge port and a closure shell closing the diffuser shell are joined by friction welding.

[0002]

2. Description of the Related Art A conventional gas generator has an ignition means which operates when a vehicle receives an impact and ignites, and a gas generation means which generates gas by operation of the ignition means. It is housed in a housing. The housing of this gas generator is generally formed by joining a diffuser shell having a gas outlet and a closure shell closing the diffuser shell, and the joining of the two shells is performed by various welding methods, for example, plasma welding, It is performed by friction welding, projection welding, electron beam welding, laser welding, TIG welding, and the like. Among these various welding methods,
When the housing is formed by joining the diffuser shell and the closure shell by friction welding, the friction welding is usually a welding method in which both members to be joined are melted by frictional heat and welded and integrated. In a welded portion, an excess portion melted by frictional heat is melted out and a projection of a welding burr is generated. Therefore, conventionally, the housing secures a space for accommodating welding burrs by, for example, bending a filter or a coolant in advance in consideration of projections of welding burrs to the joint portion between the diffuser shell and the closure shell. Therefore, the size of the housing of the gas generator is excessively large.

[0003] On the other hand, in the case of friction welding between the diffuser shell and the closure shell, if a projection space for welding burrs is not ensured in the housing, the partition wall of the housing is bent in a direction in which the welding burrs escape.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention solves the above-mentioned problems of the conventional gas generator for an air bag, and eliminates the need for a space for welding burrs generated by friction welding in the housing. By doing so, it is possible to reduce the size of the entire gas generator, and more desirably, to provide an airbag gas generator in which the peripheral wall surface of the housing is not deformed without securing such a space. And

[0005]

SUMMARY OF THE INVENTION According to the present invention, a projection of welding burrs generated at a joint between a diffuser shell and a closure shell is limited by a welding burr limiting member in a housing formed by joining both shells. Accordingly, an object of the present invention is to provide a gas generator for an airbag which achieves the above object.

That is, the present invention relates to a gas generator for an air bag, comprising a housing in which a diffuser shell having a gas outlet and a closure shell closing the diffuser shell are joined by friction welding. Gas generation for airbags, wherein welding burrs generated by friction welding with the shell are restricted from projecting inwardly of the housing by a welding burr limiting member abutting in the housing with respect to a joint portion of both shells. It is a vessel.

The above gas generator is a gas generator for an air bag using a housing formed by joining a diffuser shell having a gas discharge port and a closure shell closing the diffuser shell by friction welding. Either a mechanical gas generator that generates gas by sensing a shock exclusively by a mechanical mechanism, or a gas generator for an electric ignition type airbag that operates by an electric signal transmitted from a sensor that senses the shock may be used.

The mechanical ignition type gas generator includes a mechanical sensor that detects a shock and fires a firing pin in a housing having a gas discharge port, a primer that is pierced by the firing pin to ignite and burn, and a flame of the primer. It contains an ignition means consisting of a transfer charge that ignites and burns, a gas generator that ignites and burns with the flame of the transfer charge and generates gas, and a coolant filter that cools and purifies the generated gas. Is done. On the other hand, the electric ignition type gas generator is provided in a housing having a gas outlet,
An igniter that operates by an electric signal transmitted from a sensor that senses an impact, an ignition means that includes a transfer charge that is ignited and burned by the operation of the igniter, and ignites and burns with the flame of the transfer charge to generate gas It is configured to house a gas generating agent and a coolant filter for cooling and purifying generated gas.

In the present invention, as the welding burr limiting member, for example, a flat plate member contacting both shell joints in the housing or a coolant filter adjacent to the inner wall surface of the housing can be used. , These support welding burrs generated by friction welding and limit projections inside the housing.

This coolant filter serves to remove the combustion residue generated by the combustion of the gas generating agent and to cool the combustion gas. For example, a wire mesh made of an appropriate material is formed into an annular laminate, Compression molded products can be used. More specifically, a flat braided 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 laminate, and the laminate is compression-molded in a mold. Alternatively, a flat knitted stainless steel wire mesh is formed in a cylindrical body, and the cylindrical body is pressed in the radial direction to form a plate body. The coolant / filter can be formed by, for example, compression-molding the laminate in a mold. SUS304, SUS310S, S
Stainless steel such as US316 (JIS standard symbol) can be used. SUS304 (18Cr-8Ni-
0.06C) stainless steel exhibits excellent corrosion resistance as an austenitic stainless steel. Further, in addition to the coolant / filter for purifying and cooling the generated gas, any one of a conventionally widely used filter for purifying generated gas and a coolant for cooling generated gas is used. You can also.

The limitation of the projection of the welding burr into the housing by the welding burr limiting member is achieved by friction welding between the diffuser shell and the closure shell, and applying the welding burr limiting member to the inside of the housing at the joint portion between the two shells. This can be realized by performing the operation while touching. When using the coolant filter provided in the housing as a welding burr limiting member, the members required for the gas generator can be used. Can be When a flat member is used as the welding burr limiting member, a gap is secured between the inner wall surface of the housing and the coolant filter by the thickness of the welding burr limiting member. Since the gas flow path is used, purification and cooling of the generated gas in the coolant filter can be efficiently performed.In the present invention, the diffuser shell constituting the housing is used for friction welding of both shells. It is also possible to form a reinforcing member that limits the deformation of the housing, frictionally weld both shells, and limit the deformation of the peripheral wall surface of the housing caused by projecting welding burrs only in the outward direction of the housing. In the case where a module mounting portion projecting in a flange shape is formed on the outer periphery of the housing, the reinforcing member may be formed, for example, by thickening a portion where the module mounting portion and the outer periphery of the housing are orthogonal. it can.

Further, in the present invention, friction welding between the diffuser shell and the closure shell is performed without applying a reinforcing portion to the diffuser shell while applying a support for limiting deformation of the diffuser shell. Also, deformation of the housing peripheral wall surface due to friction welding can be prevented. This support has a shape that supports the vertical direction of the joint between the diffuser shell and the closure shell from the outside, and furthermore, after joining both shells, the support can be divided in the vertical direction of the joint. Things.

The gas generating agent used in the gas generator of the present invention includes an azide-based gas generating agent and a non-azide-based gas generating agent.
Known gas generating agents can be used. Examples of the azide-based gas generating agent include those based on inorganic azides, particularly sodium azide (sodium azide), which have been widely used in the past, such as an equivalent mixture of sodium azide and copper oxide. As the main component, a nitrogen-containing organic compound such as tetrazole, triazole, or a metal salt thereof and an oxygen-containing oxidizing agent such as an alkali metal nitrate, triaminoguanidine nitrate, carbohydrazide, nitroguanidine, etc. A nitrogen source, and an alkali metal or alkaline earth metal nitrate as an oxidizing agent,
There are compositions using chlorates, perchlorates, and the like. Considering safety and the like, non-azide gas generating agents are advantageous.

In the above-described gas generator, the ignition means is activated by the impact to ignite and burn the explosive, and the flame ignites and burns the gas generating agent to generate gas. The generated gas is cooled and purified by the coolant filter, and is injected into the airbag from the gas outlet of the housing.

Further, the gas generator for an air bag described above can be formed as an air bag device by combining an air bag which expands by introducing gas generated by the gas generator and a module case which houses the air bag. This airbag device is housed and fixed in an appropriate place in a vehicle such as a steering wheel or a dashboard.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

The gas generator for an airbag shown in this embodiment is a gas generator for a mechanical ignition type airbag. FIG. 1 is a longitudinal sectional view of a gas generator according to an embodiment of the present invention, and FIG. FIG. 3 is an enlarged cross-sectional view of a main part showing a joined state of a gas generator housing, FIG. 3 is an enlarged cross-sectional view of a main part showing a state of restricting deformation of a peripheral wall surface of the housing, and FIG. 4 is a configuration diagram of an airbag device.

A mechanical ignition type gas generator having a built-in mechanical sensor shown in FIG. 1 has a diffuser shell 2 having a gas discharge port 4 and a closure shell 3 having the diffuser shell 2 closed and having a sensor accommodating port 7. Are joined by friction welding to form the housing 1. At the time of this friction welding, a coolant filter 15 disposed in the housing 1 is in contact with the inside of the two shell joints to limit the projection of the welding burr 23 into the housing. The inside of the housing 1 is defined by a partition wall 22 into two chambers, an ignition means storage chamber 8 and a combustion chamber 9. The ignition means accommodating chamber 8 includes a detonator piece 11 in which a detonator 10 is accommodated and fixed in a recess 17, and a charge transfer agent 12 and a sensor 6 arranged vertically above and below the detonator piece 11. The ignition means is accommodated, and the gas generating agent 13 and the coolant / filter 15 are accommodated in the combustion chamber. In FIG.
Reference numeral 19 denotes a sensor safety device, reference numeral 21 denotes a combination ring, and reference numeral 30 denotes a reinforcing portion.

The primer 10 housed and fixed in the recess 17 of the primer piece 11 contains a powdery tricinate-based chemical or the like. An aluminum tape 16 is attached to the opening of the recess 17 to protect the primer 10 from moisture. Combustion chamber 9
Inside, a non-azide gas generating agent 13 and a coolant filter 15 of an annular wire mesh laminate made of stainless steel surrounding the gas generating agent are housed.

When the sensor 6 detects an impact, the gas generator fires a firing pin 18 therein, and the primer piece 11
The primer 10 housed and fixed in the recess 17 is pierced. The blasting of the firing pin 18 ignites and burns the primer 10, and the flame ignites and burns the charge 12 through the transfer hole 24 of the primer piece 11. The flame of the transfer charge 12 passes through the through hole 20 and burns the gas generating agent 13 to generate gas. The generated gas is cooled / purified by the coolant / filter 15 and discharged from the gas outlet 4.

FIG. 2 is an enlarged longitudinal sectional view of a main part showing a joined state of the gas generator housing. The diffuser shell 2 having the gas discharge port 4 and the closure shell 3 for closing the diffuser shell 2 are friction-welded. The projecting welding burrs 23 do not project into the housing 1,
It is supported by a coolant filter 15. Further, even if the projection of the welding burr 23 into the housing 1 is restricted by the coolant / filter 15, the module mounting portion 31 provided on the diffuser shell is attached to the module mounting portion 31 so that the housing peripheral wall surface does not expand outward. A thickened reinforcing portion 30 is formed. The protrusion of the welding burr 23 into the housing 1 can also be limited by abutting a plate-like member (not shown) inside the welded portion.

FIG. 3 is an enlarged sectional view of a main part showing a state of restricting deformation of the peripheral wall surface of the housing. As shown in FIG. Friction welding of both shells is performed by contacting and supporting the inner cylindrical surface of the support body 32 for controlling deformation, so that the welding burrs 23 project only to the outside of the housing 1 and the housing 1 can be friction-welded. Can be prevented from being deformed. The support body 32 divides a portion 32a that supports the upper part of the joint portion of the housing from a portion 32b that supports the lower portion so that the housing 1 after the two shells are joined can be easily taken out. be able to. Therefore, after the two shells are joined, the housing 1 can be easily taken out by dividing the support 32 in the vertical direction.

FIG. 4 is a diagram showing the construction of the airbag apparatus. The gas generator of the present invention and an airbag (bag) 100 are shown.
And a module case 101. The gas discharged from the gas discharge port 4 of the gas generator is
00, the airbag 100 breaks the module cover 102 and bulges out, forming a cushion between the steering wheel 103 and the occupant for absorbing impact.

As the gas generator, the gas generator described with reference to FIGS.

The module case 101 is made of, for example, polyurethane, and includes a module cover 102. In this module case 101, the airbag 10
The gas generator and the gas generator are housed in the pad module, and attached to the steering wheel 103 of the automobile.

The airbag 100 is formed of nylon (eg, nylon 66), polyester, or the like.
The bag opening surrounds the gas outlet 4 of the gas generator, and is fixed to the module mounting portion 31 of the gas generator in a folded state.

[0027]

Since the present invention is constructed as described above, the gas generator for an airbag of the present invention secures a space for welding burrs generated by friction welding in the housing. In addition, it is possible to provide a gas generator for an airbag in which the peripheral wall surface of the housing is not deformed without further securing such a space.

[Brief description of the drawings]

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

FIG. 2 is an enlarged longitudinal sectional view of a main part showing a joined state of a gas generator housing.

FIG. 3 is an enlarged sectional view of a main part showing a state of regulation of deformation of a peripheral wall surface of a housing.

FIG. 4 is a configuration diagram of an airbag device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Diffuser shell 3 Closure shell 6 Mechanical sensor 10 Detonator 11 Detonator piece 12 Charge transfer agent 13 Gas generating agent 23 Welding burr 30 Reinforcement part 31 Module mounting part 32 Support

Claims (9)

[Claims] 1. A gas generator for an air bag, comprising a housing in which a diffuser shell having a gas discharge port and a closure shell closing the diffuser shell are joined by friction welding, wherein friction between the diffuser shell and the closure shell is provided. A gas generator for an air bag, wherein projections inward of the housing are limited by welding burr limiting members in which welding burr generated by welding abuts in the housing with respect to a joint between the shells. 2. A coolant, wherein the welding burr limiting member is accommodated in a housing and cools and purifies generated gas.
The gas generator for an airbag according to claim 1, wherein the gas generator is a filter. 3. An airbag gas generator using a housing in which a diffuser shell having a gas discharge port and a closure shell closing the diffuser shell are joined by friction welding, wherein the diffuser shell, the closure shell, A welding burr limiting member that limits the projection of welding burr into the housing,
A method for manufacturing a gas generator for an air bag, wherein the method is performed while the shell is in contact with the inside of both shell joints. 4. A coolant, wherein the welding burr limiting member is disposed in a housing and cools and purifies generated gas.
The method for producing a gas generator for an airbag according to claim 3, wherein the gas generator is a filter. 5. A gas generator for an air bag according to claim 1, wherein a reinforcing member for limiting deformation of the housing during friction welding of the two shells is formed in the diffuser shell of the housing. . 6. A flange-like module mounting portion is formed on an outer periphery of the housing, and the reinforcing member is
The gas generator for an airbag according to claim 5, wherein the gas generator is formed in the module mounting portion. 7. The gas generation for an airbag according to claim 3, wherein the friction welding between the diffuser shell and the closure shell is further performed by applying a support member that restricts deformation of the diffuser shell. Method of manufacturing the vessel. 8. The deformation of the diffuser shell during friction welding is limited by friction welding the two shells using a support that abuts and supports the outer periphery of the shell. 3. The gas generator for an airbag according to 1 or 2. 9. A gas generator for an airbag that generates gas in response to the detection of an impact, an airbag that expands by introducing gas generated by the gas generator, and a module case that houses the airbag. And
The gas generator for an airbag, according to claim 1, 2, 5,
An airbag device, which is the gas generator for an airbag according to any one of claims 6 and 8.