JPH0761314A - Structure for fitting igniter in gas generator - Google Patents

Abstract

PURPOSE:To improve the mass-productivity by fitting an igniter to a cover of a housing easily, and to secure the safety at the time of assembling by preventing the application of heat to an igniter containing explosive. CONSTITUTION:An igniting mechanism 9 for igniting, gas generating agent 13 for generating gas with combustion, and cooling scavengers 16, 17 for cooling the generated gas are housed inside of a housing 1. The housing 1 is formed of a cylindrical shell 2 and a cover 3 for covering an opening end of the shell 2. A cylindrical adapter 11 is fixed to the cover 3 by plastic processing such as electronic beam welding. An igniter 10 of the igniting mechanism 9 is fixed to the adapter 11 by processing the adapter 11 plastically.

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 air bag mainly used for inflating and expanding an air bag such as an air bag, a life saving bag, a rubber boat, an escape chute as a safety device at the time of collision. In particular, the present invention relates to an igniter mounting structure.

[0002]

2. Description of the Related Art Conventionally, as a safety device for protecting an occupant from a shock at the time of a collision in a vehicle, especially a passenger car, an airbag device for instantaneously inflating an airbag at the time of a collision is known. This airbag device is composed of an airbag and a gas generator that generates gas for inflating the airbag. The airbag has a volume of 30 to 70 liters in the driver's seat device and 100 to 250 liters in the passenger seat device.

Further, most of the gas generators used especially in the airbag device for the driver's seat have to be housed in the pad cover at the center of the steering wheel, and are restricted in size and shape. It has a disk-shaped pressure vessel shape. When a passenger vehicle collides, the gas generating agent burns due to ignition of the ignition mechanism to generate gas, and the gas instantaneously inflates the airbag to protect the occupant from impact at the time of collision.

As a gas generator in an airbag device for a driver's seat of this type, for example, Japanese Patent Laid-Open No. 4-266548.
A structure as shown in Japanese Patent Publication has been conventionally known. That is, as shown in FIG. 8, the housing 21 includes a diffuser cup 22 formed in a cylindrical shape, a cylindrical combustion chamber cup 23 with a lid, which is concentrically welded and fixed inside the diffuser cup 22 at a predetermined interval, and an opening thereof. It is composed of a disc-shaped combustion chamber cover 24 welded and fixed to the end portion. A plurality of gas outflow holes 25 and 26 are formed on the peripheral walls of the diffuser cup 22 and the combustion chamber cup 23, respectively.

The ignition chamber 27 is formed in the center of the combustion chamber cup 23, and is located in the ignition chamber 27.
An electric igniter 28 is attached to the center of the combustion chamber cover 24 by injection molding an attachment adapter 29 made of synthetic resin. Ignition agent 30 made of boron salt stone
Is filled in the ignition chamber 27, and when the igniter 30 is ignited by the electric igniter 28, the flame accompanying combustion is propagated to the outside of the ignition chamber 27.

The combustion chamber 31 is provided on the outer periphery of the ignition chamber 27 in the combustion chamber cup 23, and a disk-shaped gas generating agent 32 is loaded inside the combustion chamber 31. Cooling collection material 3
Reference numerals 3 and 34 are respectively provided on the inner surface of the peripheral wall of the combustion chamber cup 23 and between the peripheral walls of the diffuser cup 22 and the combustion chamber cup 23 to cool the gas generated by the combustion of the gas generating agent 32 and to prevent solid sub-substances from the combustion. The biological residue is filtered.

When the electric igniter 28 is ignited by energization, the igniting agent 30 in the ignition chamber 27 is burned, and the flame is propagated from the ignition chamber 27 into the combustion chamber 31. As a result, the gas generating agent 32 is burned and gas is generated in the combustion chamber 31. This gas is cooled by the cooling and collecting materials 33 and 34, and the solid combustion residue is filtered.
Then, the purified gas is flown outward through the gas outflow hole 25 of the diffuser cup 22 to inflate and deploy the airbag.

[0008]

However, in this conventional gas generator, when the igniter 28 is attached, the combustion chamber cover 24 and the igniter 28 are attached to the die of the molding machine.
After supporting the igniter 28, the igniter 28 is fixed to the combustion chamber cover 24 by molding the mounting adapter 29 with a synthetic resin material by an injection molding method. Therefore, the mounting process of the igniter 28 to the combustion chamber cover 24 becomes complicated,
There was a problem that it took time.

Further, in this conventional gas generator,
During injection molding of the mounting adapter 29, heat of the synthetic resin material may be applied to the igniter 28 containing the explosive. Further, since the igniter 28 is fixed to the combustion chamber cover 24 by the attachment adapter 29 and then the cover 24 is welded and fixed to the combustion chamber cup 23, heat during the welding may be transferred to the igniter 28. Therefore, there is a problem in that it is difficult to ensure safety when assembling the igniter.

Further, in this conventional gas generator, since the mounting adapter 29 is made of synthetic resin, when a vehicle fire or the like is encountered, the mounting strength of the igniter 28 is lowered, and the gas generator operates. Therefore, there is a problem that the igniter 28 may fall out and be scattered.

In order to solve such a problem, for example, a female screw is formed in the mounting hole of the combustion chamber cover and
A method of forming a male screw on the outer periphery of the mounting adapter and fixing the mounting adapter to the combustion chamber cover by screwing the male screw and the female screw has also been proposed. However, in the case of such a configuration, there is a new problem that the screw machining for the combustion chamber cover and the mounting adapter is troublesome, and the mass productivity is significantly reduced.

The present invention has been made by paying attention to the problems existing in the above conventional techniques. The first
The purpose of is to install the igniter in the gas generator, which does not require complicated steps such as injection molding and screw processing, and allows the igniter to be easily attached to the cover of the housing, thereby improving mass productivity. To provide the structure.

A second object of the present invention is to install an igniter at the end of the gas generator assembling process and prevent heat from being applied to the igniter containing a gunpowder during assembly. An object of the present invention is to provide a mounting structure for an igniter in a gas generator that can ensure safety during assembly.

Furthermore, a third object of the present invention is that the igniter can be firmly fixed to the cover, and when a vehicle fire or the like is encountered, the igniter falls out along with the operation of the gas generator. An object of the present invention is to provide a mounting structure for an igniter in a gas generator capable of reliably preventing the risk of scattering.

[0015]

In order to achieve the above-mentioned object, in the invention described in claim 1, an ignition mechanism for igniting, a gas generating agent for generating gas by combustion, and a generating mechanism are provided in a housing. In the gas generator containing the cooling and collecting material for cooling the gas, the housing is composed of a cylindrical shell and a cover that covers the open end of the shell, and the cover has a cylindrical adapter. It is fixed by plastic working, and the igniter of the ignition mechanism is attached to this adapter.

The invention according to claim 2 is characterized in that, in the mounting structure for an igniter according to claim 1, the cover and the adapter are formed by press working.

Further, the invention according to claim 3 is characterized in that, in the mounting structure of the igniter according to claim 1, a seal is provided between the cover and the adapter.

Moreover, in the invention according to claim 4, in the mounting structure of the igniter according to claim 1, the igniter is fixed to an adapter by plastic working of the adapter. Is.

Further, in the invention according to claim 5, in the mounting structure of the igniter according to claim 1, the adapter is provided with a portion projecting into the shell, and a part of the gas generating agent is provided in the projecting portion. It is characterized by having supported.

[0020]

In the mounting structure of the igniter in the gas generator configured as described above, when mounting the igniter, first, the tubular adapter is fixed to the cover by plastic working. Next, the cooling scavenger is housed in the shell and the gas generating agent is supported on the cover. In this state, the cover is assembled to the open end of the shell and fixed by welding or the like. Then, the igniter is fitted into the adapter, and the igniter is fixed to the adapter by plastic working of the adapter.

Therefore, according to this igniter mounting structure, a troublesome process such as injection molding or screw processing is not required,
The igniter can be easily attached to the cover of the housing. Therefore, mass productivity can be improved in manufacturing the gas generator. Also, since the igniter is installed at the end of the gas generator assembly process, heat generated during assembly such as welding of the cover can be prevented from being applied to the igniter containing the explosive. The safety of can be secured. Furthermore, since the igniter can be firmly fixed to the cover, it is possible to reliably prevent the risk of the igniter falling out and scattering due to the operation of the gas generator when a vehicle fire or the like is encountered.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a gas generator for an air bag embodying the present invention will be described in detail below with reference to FIGS.

As shown in FIGS. 1 to 3, a housing 1 of a gas generator includes a substantially capped cylindrical shell 2 and a substantially disk-shaped cover 3 fitted and welded to an open end of the shell 2. And a combustion chamber 4 is formed therein. The annular accommodation recess 5 is formed concentrically on the outer circumference of the shell 2 and opens toward the side opposite to the opening direction of the shell 2.

A plurality of gas outflow holes 6 are formed in the peripheral wall of the shell 2, and the combustion chamber 4 is communicated with the accommodation recess 5 through the gas outflow holes 6. The mounting flange 7 is formed on the outer peripheral edge of the opening end of the accommodation recess 5, and the mounting flange 7 is provided with a plurality of bolt insertion holes 8 for mounting on a steering wheel of a vehicle.

The electric igniter 10 of the ignition mechanism 9 is fitted and fixed in the center of the cover 3 via a cylindrical mounting adapter 11 so as to be located at the center of the combustion chamber 4 of the housing 1. The lead wire 12 is connected to the outer end. A plurality of gas generating agents 13 are loaded into the combustion chamber 4 of the housing 1 via a sheet-shaped pressing member 14 so as to be located on the outer periphery of the electric igniter 10. Further, each gas generating agent 13 is formed into a rod shape having a circular cross section by extrusion molding or the like, and is aligned and arranged so as to extend in parallel along the axial direction of the housing 1.

As an extrusion molding method of the gas generating agent 13, there is, for example, the following method. That is, oxidizing agents such as perchlorates and nitrates, binders such as nitrocellulose, cellulose acetate and ethyl cellulose, plasticizers,
An appropriate amount of a solvent is added to a raw material composed of a combustion control agent and the like and uniformly mixed to prepare a drug mass. For example, a drug mass is prepared from raw materials of 63% by weight of potassium perchlorate, 12% by weight of cellulose acetate, 5% by weight of dimethyl phthalate, and 20% by weight of dihydrate of bitetrazole manganese salt.

[0027] This drug mass is loaded into a companding machine and pressure is applied,
By extruding through a die attached in advance to the companding machine, a rod having a predetermined outer diameter shape and outer diameter dimension is formed. Then, this molded product is cut into a predetermined length according to the dimensions of the housing 1 and then dried.

On the other hand, the circular sheet-shaped igniting agent 15 is disposed at one end of the combustion chamber 4 of the housing 1 and is in contact with one end surfaces of the electric igniter 10 and the gas generating agent 13.
The igniting agent 15 is formed, for example, by immersing a disk-shaped glass fiber sheet in a slurry-like chemical and then drying it. The plurality of rod-shaped gas generating agents 13 are sandwiched and held between the sheet-shaped igniting agent 15 and the pressing material 14.

The igniting agent 15 includes, for example, 30% by weight of boron and 70% by weight of potassium nitrate to which an appropriate amount of binder is added, or 60% by weight of magnesium and 40% by weight of polytetrafluoroethylene. And the like. Then, by adding a solvent such as acetone to these compositions and stirring and mixing, a slurry state can be obtained.

The cooling scavenger 16 is arranged with a predetermined thickness on the inner surface of the peripheral wall of the combustion chamber 4 so as to surround the outer periphery of the gas generating agent 13. For example, a stainless steel plain weave wire mesh of 24 mesh is wound three times. Things are being used. The cooling collector 17 is accommodated in the accommodation recess 5 and is fixed by a retaining ring 18 so as not to come off.
A compression-molded 6 mm stainless steel knit wire is used. Then, the gas generated by the combustion of the gas generating agent 13 is cooled when passing through the cooling and collecting materials 16 and 17, and the solid combustion residue in the gas is filtered.

Next, the mounting structure of the electric igniter 10 will be described. First, in this embodiment, the shell 2, the cover 3 and the mounting adapter 1 of the housing 1 are described.
1 is formed by press forming a plastically workable metal material. Examples of this material include stainless steel, titanium and titanium alloys, and aluminum alloys or magnesium alloys that have undergone heat treatment, that is, processing, heat treatment, or a composite treatment thereof.

These plastically workable metal materials have the property that they are hardened by press working or heat treatment and their strength is increased. Therefore, when this metal material is used, a predetermined strength can be secured even if the thickness of the shell 2, the cover 3 and the mounting adapter 11 is reduced. The thickness of the shell 2 and the cover 3 is 1.0 to 2.0.
It can be set within the range of mm, and is preferably about 1.5 mm. Moreover, since the mounting adapter 11 does not require strength as compared with the shell 2 and the cover 3, the thickness of the adapter 11 can be set within a range of 0.5 to 1.0 mm, and is 0.8 mm. A degree is preferable.

By the way, in this embodiment, stainless steel (Japanese Industrial Standard SUS304L) is used, the thickness of the shell 2 and the cover 3 is set to 1.5 mm, and the thickness of the adapter 11 is set to 0.8 mm. There is. This stainless steel is a preferable material because it has high strength and is work hardened by press working to further increase its strength. Therefore, according to this embodiment, the thickness of the shell and the cover can be considerably reduced as compared with the conventional configuration in which the thickness is set to 1.5 to 4 mm.

When the shell 2, the cover 3 and the mounting adapter 11 are required to have corrosion resistance, light weight and strength, titanium and titanium alloys are preferably used. When the shell 2, the cover 3 and the mounting adapter 11 are required to have corrosion resistance, light weight and easy processing, it is preferable to use a tempered aluminum alloy or magnesium alloy.

Further, as shown in FIGS. 4 and 5, an opening 3a and a cylindrical portion 3b protruding from the opening edge toward the combustion chamber 4 side are formed in the central portion of the cover 3, and the cylindrical portion is formed. A protruding portion 3c extending toward the center is formed at the tip of 3b. On the other hand, the mounting adapter 11 includes a large-diameter portion 11 having an outer diameter larger than the diameter of the opening 3a of the cover 3.
a and a small diameter portion 11b having an outer diameter smaller than the diameter of the opening 3a of the cover 3 are provided, and a step portion 11c is formed between the large diameter portion 11a and the small diameter portion 11b.

When mounting the electric igniter 10, first, as shown in FIG.
From the tip side of the tubular portion 3b into the inside of a, the mounting adapter 11
The small-diameter portion 11b is inserted and the step portion 11c is joined to the overhanging portion 3c of the cover 3. Next, as shown in FIG. 5, the joint between the overhang 3c and the step 11c is welded by spot welding, electron beam welding, laser welding, or the like, and the joint is sealed. As a result, the mounting adapter 11 can be firmly fixed to the cover 3 in an airtight state.

Then, as shown in FIG. 6, the large-diameter punch 19 is fitted from the large-diameter portion 11a side of the mounting adapter 11 and the small-diameter punch 20 having the taper portion 20a is fitted from the small-diameter portion 11b side. Press. As a result, the small-diameter portion 11b is plastically deformed toward the tubular portion 3b of the cover 3, and the mounting adapter 11 is attached to the protruding portion 3c of the cover 3.
Fixed to. In this state, the cover 3 is used in the assembly process of the entire gas generator.

Then, in the process of assembling the gas generator, the sheet-shaped igniting agent 15 is disposed on the inner top of the shell 2 and the cooling collecting material 17 is accommodated in the accommodation recess 5. Also,
A plurality of gas generating agents 1 are provided on the cover 3 via a pressing member 14.
3 are arranged and supported, and the cooling and collecting material 16 is circulated around the outer periphery of the gas generating agent 13. At this time, as shown in FIG. 1, a part of the gas generating agent 13 is also supported on the tip of the large diameter portion 11a of the mounting adapter 11.

In this state, the cover 3 is fitted to the open end of the shell 2 and the joints thereof are welded by electron beam welding, laser welding or the like to fix the cover 3 to the shell 2 in an airtight state. . This allows shell 2 and cover 3
The housing 1 is formed by and the gas generating agent 13 and the igniting agent 15 are accommodated in the combustion chamber 4 of the housing 1 in a confronting state. At this time, a part of the gas generating agent 13 arranged near the center is supported on the tip of the large-diameter portion 11a of the mounting adapter 11 protruding into the combustion chamber 4.

Finally, as shown in FIG. 7, the electric igniter 10 is inserted into the mounting adapter 11 from the outside of the cover 3, and the large-diameter collar 10a of the igniter 10 is attached to the small-diameter portion of the mounting adapter 11. Engage with the inner top of 11b. Then, in this state, the tip edge of the small-diameter portion 11b is crimped along the large-diameter collar 10a of the igniter 10 and plastically deformed, so that the igniter 10 is in contact with the ignition agent 15 in the combustion chamber 4. , Can be fixed to the mounting adapter 11.

In this case, the seal ring 10b is provided between the outer peripheral surface of the igniter 10 and the inner peripheral surface of the mounting adapter 11.
And a sealant (not shown) is applied between the large-diameter collar 10a of the igniter 10 and the caulking portion of the mounting adapter 11. Thereby, the igniter 10 can be attached to the attachment adapter 11 in an airtight state.

In the gas generator for an air bag constructed as described above, when a detection signal is generated due to a collision of a vehicle or the like, a predetermined current flows through the electric igniter 10 through the lead wire 12. , The igniter 10 is ignited. The sheet-shaped igniting agent 15 is combusted by this ignition, and the flame thereof is in contact with the igniting agent 15.
3 propagates directly to Thereby, a plurality of gas generating agents 1
3 are simultaneously ignited and burned to generate gas such as nitrogen gas in the combustion chamber 4. The gas flows out of the casing 1 through the gas outflow holes 6, and at the same time, the cooling and collecting materials 16, 17
The air bag (not shown) is inflated.

As described above, according to the mounting structure of the igniter in the gas generator of this embodiment, the tubular adapter 11 is fixed to the cover 3 by its plastic working, and the igniter 10 is attached to the adapter 11. It is adapted to be fixed by the plastic working of 11. For this reason,
The igniter 10 can be easily attached to the cover 3 of the housing 1 without requiring complicated steps such as injection molding and screw processing. Therefore, mass productivity can be improved in manufacturing the gas generator.

In the igniter mounting structure of this embodiment, the igniter 10 can be incorporated in the combustion chamber 4 of the housing 1 at the end of the gas generator assembly process. Therefore, when welding the adapter 11 to the cover 3,
When welding the cover 3 to the shell 2 or the like, it is possible to prevent heat generated by the welding from being applied to the igniter 10 containing the explosive. Therefore, the safety at the time of assembling the igniter 10 can be ensured.

Furthermore, in the mounting structure of the igniter of this embodiment, the igniter 10 can be plastically processed by the adapter 11.
It can be attached to the cover 3 via.
Therefore, the igniter 10 can be firmly fixed to the cover 3. Therefore, when a vehicle fire or the like is encountered, the mounting strength of the adapter 11 does not decrease with the operation of the gas generator, and the risk of the igniter 10 falling out and scattering can be reliably prevented.

The present invention is not limited to the configuration of the above-described embodiment, and can be embodied by making the following arbitrary changes without departing from the spirit of the present invention. (1) Without welding the joint between the overhanging portion 3c of the cover 3 and the stepped portion 11c of the mounting adapter 11, a gasket or the like may be interposed or a sealant may be applied to the joint. , Keep airtight. (2) An aluminum foil or the like is attached to the inner peripheral surface of the shell 2 to close the gas outflow hole 6 to prevent moisture inside the combustion chamber 4. (3) The rod-shaped gas generating agent 13 has a C-shaped cross section, a single-hole tubular shape having a through hole in the center, or a multi-hole tubular shape having a large number of holes. (4) As the gas generating agent 13, use a pellet-shaped material or a disk-shaped material. (5) Use a forged product for the cover 3 and the mounting adapter 11.

[0047]

Since the present invention is configured as described above, it has the following excellent effects.

According to the first aspect of the present invention, the igniter can be easily attached to the cover of the housing without the need for complicated steps such as injection molding and screw processing.
Mass productivity can be improved.

Further, according to the invention described in claim 1, the igniter can be incorporated at the end of the assembling process of the gas generator, and the heat at the time of assembling is not applied to the igniter containing the explosive. As a result, safety during assembly can be ensured.

Further, according to the invention of claim 1,
The igniter can be firmly fixed to the cover, and when a vehicle fire or the like is encountered, the risk of the igniter falling out and scattering due to the operation of the gas generator can be reliably prevented.

Moreover, according to the invention of claim 2,
The strength of the cover and the adapter itself can be improved, and the igniter can be more firmly fixed to the cover.

According to the third aspect of the invention, the adapter can be fixed to the cover in an airtight state. Further, according to the invention of claim 4, the igniter can be easily attached to the adapter,
The igniter assembly process can be further simplified.

According to the invention described in claim 5,
A part of the gas generating agent can be supported by utilizing the protruding portion of the adapter, so that the gas generating agent can be easily loaded.

[Brief description of drawings]

1 is a sectional view taken along the line AA of FIG. 3, showing an embodiment of a gas generator for an air bag embodying the present invention.

FIG. 2 is a front view of the gas generator.

FIG. 3 is also a plan view of the gas generator.

FIG. 4 is a cross-sectional view showing a step of inserting an adapter into a mounting hole of the cover, particularly in a step of assembling the electric igniter with the cover.

FIG. 5 is a sectional view showing a process of assembling the electric igniter to the cover, particularly a process of welding an adapter to a mounting hole of the cover.

FIG. 6 is a sectional view showing a process of assembling the electric igniter to the cover, particularly a process of fixing the adapter to the mounting hole of the cover by press working.

FIG. 7 is a sectional view showing a step of assembling the electric igniter to the cover, particularly a step of inserting and fixing the igniter in the adapter.

FIG. 8 is a cross-sectional view showing a conventional gas generator.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Housing, 2 ... Shell, 3 ... Cover, 3a ... Opening part, 3b ... Cylindrical part, 3c ... Overhang part, 4 ... Combustion chamber, 5 ... Housing recess, 9 ... Ignition mechanism, 10 ... Electric igniter, 10a ... Large-diameter collar, 11 ... Mounting adapter, 11a ... Large-diameter portion as a protruding portion, 11b ... Small-diameter portion, 11c ... Step portion, 13
... Gas generating agent, 15 ... Ignition agent, 16 ... Cooling collector, 17
… Cooling collector.

Claims (5)

[Claims] 1. A gas generator in which an ignition mechanism for igniting, a gas generating agent for generating a gas by combustion, and a cooling trapping material for cooling the generated gas are housed in a housing, wherein the housing is a cylinder. A shell-shaped shell and a cover that covers the open end of the shell, a cylindrical adapter is fixed to the cover by plastic working, and the igniter of the ignition mechanism is attached to the adapter. Mounting structure of igniter in gas generator. 2. The mounting structure for an igniter in a gas generator according to claim 1, wherein the cover and the adapter are formed by press working. 3. The mounting structure for an igniter in a gas generator according to claim 1, wherein a seal is provided between the cover and the adapter. 4. The mounting structure for an igniter in a gas generator according to claim 1, wherein the igniter is fixed to an adapter by plastic working of the adapter. 5. The mounting of an igniter in a gas generator according to claim 1, wherein the adapter is provided with a portion projecting into a shell, and a part of the gas generating agent is supported by the projecting portion. Construction.