JPH0948311A - Air bag device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems that efficient holding area can not be provided as tensile stress is concentrated at unfolding of an air bag, working and assembling processes become complicated and material and working costs are increased for reinforcing the holding area. SOLUTION: An air bag device has an inflator 22 having a fitting flange 22 on its peripheral surface for spouting out gas, an air bag 24, an air bag cover 23, a base plate 21 for supporting the air bag with the fitting flange and retainer ring 25, and the air bag 24 is formed into a bag shape substantially sealed which has no fitting opening of the inflator. A lead inserting hole 24C of the inflator is formed in a part of the air bag and the inflator is previously stored in the air bag, and when fitting, a part of the air bag is doubly held and fixed in a ring shape by the base plate 21 and the retainer ring 25 through the fitting flange 22c of the inflator 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag device for protecting an occupant against an impact such as a vehicle collision.

[0002]

2. Description of the Related Art For example, an air bag device for a driver is built in a center pad of a steering wheel, and an air bag is inflated and deployed instantaneously by detecting an impact such as a collision of a vehicle to protect the driver. ing. For this reason, the steering wheel body is provided with an attachment portion for the airbag module, and is attached by fastening the attachment piece provided on the airbag module with a cap screw or the like.

A conventional inflator for inflating an airbag comprises a metal container having a mounting flange on its peripheral surface, a small amount of igniting agent is arranged in the center of the inside thereof, and a large amount of nitrogen gas is provided around the igniting agent. A tablet that instantly generates, etc. is arranged, and first, an igniter is made to react, the reaction of the tablet in contact therewith is started, and the airbag is inflated and deployed. Usually, the inflator mounted on the steering wheel has a flat cylindrical shape and has a larger diameter than its length.

On the other hand, a conventional airbag is formed by stacking a pair of sheet materials, for example, a woven cloth material such as polyamide, and sewing the circumference thereof. An opening for fitting an inflator is provided in one of the circular woven fabric materials, and a plurality of bolt insertion holes for bolting are provided at a peripheral edge of the opening at predetermined intervals. Then, in order to reinforce the opening and the bolt insertion hole to secure the attachment strength, separate ring-shaped reinforcing cloths are stacked and sewn together. And
A general airbag device that employs the inflator having the above-described configuration has, for example, the configuration disclosed in Japanese Utility Model Laid-Open No. 2-91051. That is, the airbag is provided with a circular opening into which an upper portion of an inflator having a gas ejection port is fitted, and at the periphery of the opening, for example, four bolt through holes are provided, and the opening and four bolts are inserted. In order to reinforce the holes at the same time, a ring-shaped patch cloth is sewn together and combined. Also, the actual Kaihei 4-55
Japanese Patent Laid-Open No. 446 discloses a structure in which an exhaust hole is provided in the peripheral portion of the opening. It is also common to provide such an exhaust hole.

In order to attach the airbag having the above structure to the base plate, a retainer ring provided with stud bolts is inserted into the inside of the airbag in advance, and the stud bolts are inserted through the bolt insertion holes. After being inserted into the through hole provided in the mounting flange of the inflator, it is further inserted into the mounting hole of the base plate and fastened with a nut or the like. In this way, the circular opening peripheral edge of the airbag is firmly sandwiched by the retainer ring and the mounting flange of the inflator.

[0006]

When the airbag is deployed, tensile stress is concentrated on the peripheral portion of the stud bolt, and at the same portion, the inner peripheral width of the airbag peripheral edge is reduced by the diameter of the through hole. As a result, a sufficient sandwiching area cannot be obtained and the required strength cannot be obtained. Therefore, the same portion must be reinforced particularly with seams and patch cloths. Also,
In order to hermetically sandwich the circular opening peripheral edge, it is necessary to have a predetermined thickness. Therefore, although a relatively wide surface can be sandwiched between the retainer ring and the mounting flange of the inflator at portions other than the peripheral edge of the bolt insertion hole, the entire peripheral edge of the opening must be excessively reinforced with a uniform thickness. . Therefore, there is a problem that the process becomes complicated and the material cost and the processing cost also increase.

The present invention has been made in order to solve the above problems, and an air bag can be firmly attached by a simple method, and it is possible to easily realize an ideal inflated form without loss during inflation. An object of the present invention is to provide an enabled airbag device.

[0008]

In order to achieve the above object, the most important structure of the present invention is to provide an inflator having a mounting flange on its peripheral surface for ejecting gas and an air inflated by the gas ejected from the inflator. In an airbag device including an airbag module including a bag, a case body that houses the airbag, and a base plate that supports the airbag together with the mounting flange, the airbag has an opening for inserting the inflator. It is a substantially hermetically sealed bag body in which a small diameter hole such as a lead wire insertion hole or an exhaust hole is appropriately formed in a part thereof.

In order to attach the airbag to the base plate, it is necessary that the inflator is stored inside the airbag in advance. Therefore, when a plurality of airbag-constituting cloth materials having a predetermined shape are overlapped and the peripheral edge thereof is sewn, the inflator is arranged so as to be wrapped in the cloth material in advance and the entire peripheral edge is sewn, or a plurality of air bags are sewn. When the bag-constituting cloth materials are overlapped and the peripheral edge thereof is sewn, the sewn portion is left in advance, leaving an unsewn portion into which the inflator can be inserted. At the time when the peripheral edges of the constituent cloth materials are all sewn to complete a complete bag-shaped airbag, the inflator is already stored in the inside thereof.

The air bag in which the inflator is built in beforehand is partially sandwiched and fixed by the front and back surfaces of the flange, the peripheral edge of the opening for inserting the inflator of the base plate, and the retainer ring. Become. The fixing at this time is performed by directly fastening the base plate and the retainer ring with bolts or the like without inserting the airbag and the mounting flange.

When forming a space around the opening of the base plate to allow the mounting flange of the inflator to vertically pass therethrough, the inflator together with the airbag is connected to the opening of the base plate through the space and the opening. After passing through, lay it sideways, lock the flange in the opening, and arrange a retainer ring so that it can be attached to the base plate via the airbag, and insert the base plate and the retainer ring into the airbag and the mounting flange. Fasten directly with bolts, etc. without In this case, before the inflator passes through the opening of the base plate, the airbag can be previously folded into a predetermined size in a predetermined procedure.

As described above, for fastening with bolts or the like, a plurality of stud bolts are provided on either the base plate or the retainer ring, and a bolt insertion hole for inserting the stud bolt is provided on the other side. The stud bolt and the bolt insertion hole are provided so as to be located outside the mounting flange of the inflator.

With such a construction, the inflator fitting insertion opening and the bolt insertion hole for attachment are unnecessary in the airbag, and at the same time, it is not necessary to reinforce the periphery of the opening and the bolt insertion hole. Since the inflator mounting flange is sandwiched by the retainer ring and the airbag is sandwiched and fixed in a double ring shape, a sufficient mounting strength is secured. At the same time, the process of assembling and assembling the airbag and the airbag module is simplified, the number of parts is reduced, and not only the productivity can be increased but also the cost can be reduced. . Furthermore, when the airbag is inflated and deployed, local tensile stress does not act on the mounting portion of the airbag, so that the airbag is not required to be reinforced as described above and damage is prevented.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below based on the best examples.

1 to 6 relate to a first embodiment of the present invention,
1 is a front view of a steering wheel equipped with an airbag device according to a first embodiment of the present invention, FIG. 2 is an exploded perspective view of the steering wheel, and FIG. 3 is a sectional view taken along line I-I of the airbag module in FIG. FIG. 4 is a sectional view, FIG. 4 is a plan view of the airbag, FIG. 5 is an exploded perspective view of the same, and FIG. 6 is an explanatory view of inserting the inflator into the airbag.

The steering wheel 1 comprises a steering wheel body 2 and a pad portion 4, etc. The steering wheel body 2 has an annular wheel ring 3 and a pad portion 4 mounted at a position deviated downward from the center thereof. The boss plate 5 is integrally attached with a boss fitted to a steering shaft (not shown) provided on the vehicle body side, and a plurality of spokes 6 that connect the wheel ring 3 and the boss plate. Brackets are provided on the left and right ends of the boss plate 5, and guide bolts 7 are attached to the brackets. The brackets are guided by the guide bolts 7 via an insulating member, and elastically supported by the coil spring 8 at the upper limit. The base plate 21 of the airbag module 20 forming the pad portion 4 is fastened and attached to the attached tongue piece 9a of the movable plate 9 by a cap bolt or the like (not shown).

As shown in FIGS. 2 and 3, the air bag module 20 is provided with a base plate 21, an inflator 22, an air bag cover 23, an air bag 24 and the like. In the illustrated example, the air bag cover 23 is different from the conventional one. Similarly, it is molded from various soft elastomer resins such as thermoplastic urethane elastomer and thermoplastic polyester elastomer, and has a mounting frame portion 23a and this mounting frame portion 2
3a is a flat plate-like cleaving portion 23b having an eaves portion extending beyond the periphery, and the cleaving portion 23b is provided with a substantially H-shaped tear line 23c formed of a thin portion. Is virtually the same as before.

The structure of the inflator 22 is the same as that of the conventional one described above. The whole structure is a flat cylindrical shape, and the ring-shaped mounting flange 22c having a substantially rectangular outer shape is attached to the center of the peripheral surface thereof. Has been. The upper portion sandwiching the flange 22c constitutes a gas injection portion 22a, and a plurality of gas injection holes 22d are formed on the side wall of the gas injection portion 22a at predetermined intervals. Also,
Lower part 2 of inflator 22 which sandwiches the flange 22c
A lead-out hole for the lead wire 10 connected to the inside is provided at the center of the bottom surface of 2b.

The base plate 21 is the inflator 2
2 and the air bag 24 together, as shown in FIGS. 2 and 3, the plate body 21a having a substantially trapezoidal shape has a side wall 21b extending downward at the periphery of the plate body 21a. The central portion has an opening 21c into which the lower portion 22b of the inflator 22 is inserted. In addition, a bolt insertion hole 21d through which the stud bolt 25a fixed to the retainer ring 25 is inserted is formed at each of four corners of the plate body 21a, and a plurality of rivets through which the blind rivet 40 is inserted through the side wall 21b. An insertion hole 21e is formed.

The retainer ring 25 is a ring body having an L-shaped cross section, the inner diameter of which is set slightly larger than the outer diameter of the gas injection portion 22a of the inflator 22, and the inflator 22 which forms a substantially rectangular plane. The four stud bolts 25a are integrally fixed by welding or the like to the outside of the mounting flange 22c outside the minimum diameter portion and at positions corresponding to the bolt insertion holes 21d of the base plate 21. It is set up.

The airbag 24 of the present invention is the most important component, and the airbag 24 is not provided with an opening for inserting the inflator 22.
Except for the conventional exhaust hole, it is configured as a substantially sealed bag. FIG. 4 is a plan view in which the exhaust holes of the airbag 24 according to the present embodiment are omitted, and shows a state in which the inflator 22 is not yet built in. As shown in FIG. 5, the airbag 24 has a circular sheet material, for example, two circular upper and lower circular woven cloths 24 woven with a fiber thread of polyamide resin.
a, 24b, and a through hole 24c for a circular lead wire or the like having a diameter of about 20 mm is formed in the approximate center of the lower woven fabric 24b. Suture.

At this time, as shown in FIG.
Leave d and sew. When the unsewn portion 24d is spread so as to separate the two woven cloths 24a and 24b from each other,
An opening 24e as shown in FIG. 6 is obtained, and this opening 24e
Then, the entire inflator 22 including the lead wire 10 is inserted into the airbag 24. The lead wire 10 is attached to the center of the lower surface of the inflator 22, and the inflator 22 is moved inside the airbag 24 to pull the lead wire 10 out of the airbag 24 through the lead wire insertion hole 24c. Next, the unsewn portion 24d is sewn to complete the sewing over the entire length of the peripheral portion of the airbag 24. Preferably, when the unsewn portion 24b is sewn, the sewn portion extending in front of and behind the unsewn portion 24d may be double stitched so that the seams overlap by about 10 mm.

The airbag module 20 according to this embodiment.
In order to assemble, first, the airbag 24 is inserted through the retainer ring 25 and pulled out upward as shown in FIG. At this time, the four stud bolts 2 of the retainer ring 25
5a to the flange portion 22c of the inflator 22, respectively.
The airbag 24 is pulled up so as to be positioned outside the minimum diameter portion of the retainer ring 25, and the retainer ring 25 is brought into contact with the flange portion 22c of the inflator 22 via the airbag 24.

Airbag 2 combined in this way
4. The retainer ring 25 and the inflator 22 are fitted so that the lower portion 22b of the inflator 22 is inserted into the opening 21c of the base plate 21 together with a part of the airbag 24, and the stud bolts 25a are respectively associated with the base plate 21. Bolt insertion hole 21d
Then, it is fastened and fixed with a nut 26.

Next, the portion of the airbag 24 pulled out above the retainer ring 25 is compactly folded so as to fit within the outer diameter of the base plate 21, the airbag cover 23 is covered from above, and a plurality of blind rivets 40 are provided. Thus, the base plate 21 and the airbag cover 23 are firmly fixed as shown in FIG. 3 to complete the airbag module 20.

In the air bag module 20 having the above-mentioned structure, the air bag 24 has the same structure as that of the inflator 2 in the conventional manner.
Since it is not necessary to form an opening for inserting 2
The excision process and the reinforcement work for that are eliminated, and the manufacture of the airbag 24 becomes easy. In addition, in this embodiment, the retainer ring 25 is fitted from the outside of the airbag 24 and brought into contact with the mounting flange 22c of the inflator 22 via the airbag 24, and the base plate 21 is opposed to the retainer ring 25 and the airbag 24 Mounting flange 22c of the inflator 22 fitted from the outside
Since the air bag 24 is brought into contact with the surface opposite to the above with the stud bolt 25a and the nut 26, the fastening work is also easy.

Particularly, when assembling a conventional air bag module, a plurality of bolts housed inside the air bag are inserted through bolt insertion holes formed in the constituent members such as the air bag, the inflator and the base plate. Although complicated work is required, when assembling the airbag module 20 according to the present embodiment as described above, not only is the stud bolt 25a fixed to the retainer ring 25, but also all of these fastening elements are provided. It is visible, and positioning and fastening work can be done easily, allowing partial automation.

Further, since the airbag is sandwiched between the upper surface of the mounting flange 22c and the lower surface of the retainer ring 25, and between the lower surface of the flange 22c and the upper surface of the base plate 21 in a ring shape, the airbag is doubly clamped. Airbag 2
4 can be firmly attached to the base plate 21, and the airbag 24 is evenly held in a U-shaped cross section over the entire front and back surfaces of the mounting flange 22c. Since the insertion hole is not formed, the tensile stress is not concentrated on a specific portion of the airbag mounting portion, and the airbag 24 is not damaged when the airbag 24 is deployed. This means that it is possible to reduce or simplify an extra member such as a patch cloth for reinforcement and a complicated process such as stitching and reinforcement, which are required in the related art. Further, since the sandwiching surface of the airbag 24 is completely sealed, the gas generated from the inflator 22 does not escape to the lower portion of the inflator 22, so that it is not necessary to reinforce or seal the lead wire insertion hole 24c. Can be simplified.

Although the airbag is sewn in two steps in the above embodiment, the inflator 22 is previously stored between the two overlapping woven fabrics 24a and 24b, and the same fabric is woven. It is also possible to sew all the peripheral edges of the cloths 24a and 24b by a one-step sewing operation to manufacture the airbag 24 having the inflator 22 built therein.

FIG. 7 is an exploded perspective view of a steering wheel equipped with an airbag device according to a second embodiment of the present invention,
FIG. 8 is a sectional view of the airbag module in the same embodiment. In these figures, the parts designated by the same reference numerals as those in the first embodiment have substantially the same configuration.

The airbag module 200 includes the first
Similar to the embodiment, the base plate 210 and the inflator 2
2, an airbag cover 23, an airbag 24, a retainer ring 25 and the like. This embodiment is different from the first embodiment in that the base plate 21
0 and the retainer ring 25 are arranged upside down, and the base plate 210 is formed with a slit-shaped passage gap 215 required to vertically pass the mounting flange 22c of the inflator 22. .

In addition, 4 of the base plate main body 211
Side walls 21 extending downward along the periphery of a plate body 211 having a substantially trapezoidal shape similar to the first embodiment except that stud bolts 214 are integrally provided at the corners so as to project downward.
2, the opening 213 for inserting the gas injection portion 22a of the inflator 22 is formed in the center of the plate body 211, and the plurality of rivet insertion holes 216 for inserting the blind rivet 40 are formed in the side wall 212. Has been done.

The retainer ring 25 is a ring body having an L-shaped cross section, the inner diameter of which is set to be slightly larger than the outer diameter of the gas injection portion 22a of the inflator 22, and the inflator 22 which forms a substantially rectangular plane. Of the flange portion 22c outside the minimum diameter portion and at positions corresponding to the stud bolts 214 protruding from the base plate 210, respectively.
A bolt insertion hole 25c for inserting 4 is formed.

As described above, the steering wheel body 2 includes the coil spring 31, the movable plate 35 electrically insulated by the pair of upper and lower insulators 32a and 32b, and the pair of left and right switch devices 30 having the guide bolts 36. Boss plate 2a and spoke core metal 2
The brackets provided integrally with b and 2c are supported by a predetermined pressing force so as to be movable downward against the elastic force of the coil spring 31. A support piece 35 a for supporting the airbag module 200 is provided on the movable plate 35 upright. Further, a contact 35c made of copper or the like is attached to the flat plate portion 35b of the movable plate 35, while a fixed contact 2d contacting the contact 35c is provided on the steering wheel body side where the movable plate 35 contacts at the lower limit. It is provided integrally.

Next, the airbag module 200 according to the second embodiment will be described with reference to FIG. 7 according to its assembling procedure. Similar to the first embodiment, the airbag 24 is formed into a bag body by laminating two circular nylon cloths and the like and stitching the peripheral portions thereof. An insertion hole 24c for the lead wire 10 is formed in the center of the woven cloth 24b which becomes the lower surface when unfolded, and the inflator 22 is inserted between the two circular woven cloths 24a and 24b and then attached to the inflator 22. The lead wire 10 is pulled out from the lead wire insertion hole 24c, the circumferences of the two circular woven cloths 24a and 24b are aligned, and the entire peripheral edges thereof are continuously sewn with a sewing machine or the like.

As shown in FIG. 8, the airbag 24 having the inflator 22 built in substantially in the center of the airbag cover 23 is slackened on the lead wire pull-out side of the airbag 24 according to a preset folding procedure. It is folded so that it has a predetermined shape to be accommodated in the internal space.

With the airbag 24 folded in this manner, the mounting flange 22c of the internal inflator 22 is erected against the flat surface of the base plate body 211 so that the passage space 21 formed in the base plate 210.
5, while at the same time inserting the body of the inflator 22 into the insertion opening 213 of the base plate 210,
The opening 213 is passed through together with the airbag 24.

After this passage, the posture of the inflator 22 is changed so that the upper and lower surfaces of the inflator 22 are substantially parallel to the plane of the base plate body 211, and the airbag 24 is pulled back upward so that the upper surface of the flange portion 22c of the inflator 22 is inflated. It is brought into contact with the lower surface of the base plate 210 via the bag 24. Next, the lower part 2 of the inflator 22
A retainer ring 25 is fitted into 2b via an airbag 24. Bolt insertion hole 25c of retainer ring 25
The stud bolts 214 of the base plate 210 are inserted into the base plate 210, and the nuts 26 doubly sandwich the front and back surfaces of the mounting flange 22c of the inflator 22 between the base plate 210 and the retainer ring 25 via a part of the airbag 24. As it is, it is tightened and fixed integrally. At this time, the stud bolt 214 is located outside the mounting flange 22c of the inflator 22.

Next, the air bag cover 23 is covered, and the plurality of blind rivets 40 are inserted into the rivet insertion holes of the base plate 210 and the air bag cover 23 to firmly attach the air bag cover 23 to the base plate 210 and the air module 200 is completed. To do. The airbag module 200 is attached to the movable plate 35 of the steering wheel body 2 attached to the steering shaft of the vehicle body with a cap bolt. Further, the lead wires such as the inflator 22 and the horn are wired to complete the work.

The operation of the airbag device according to the second embodiment is almost the same as that of the above-described first embodiment, but in addition to the first embodiment, the airbag 24 has a predetermined shape before it is attached to the base plate 210. The base plate 210 and the retainer ring 25 can be folded, and the work of fastening the retainer ring 25 with the bolts and nuts becomes easier.

In the present invention, in order to further improve the sealability of the mounting portion of the airbag with respect to the base plate, the mounting flange 22 of the inflator 22 is used.
Elastic sealing materials made of synthetic rubber or soft synthetic resin may be attached to the front and back of c.

Further, although the above-described airbag modules 20 and 200 use the inflator 22 having the mounting flange at the substantially center of the periphery thereof, the present invention is not limited to such an inflator, and the upper surface of the peripheral surface is not limited thereto. Alternatively, there may be a case where an inflator having a mounting flange at the lower end of the peripheral surface or being displaced downward is used.

Further, in addition to the inflator of the type in which the energy for starting the inflator, the collision sensor, etc. are dependent on the vehicle body side and are activated by the electric signal as described above, a mechanical acceleration sensor or the like is provided in the inflator body. It is also possible to use a direct start-up type inflator that is built in integrally and operates without supplying electric energy from the outside.The airbag combined with such an inflator does not have the inflator in the center of the circular cloth below. An operating rod insertion hole into which an operating rod for releasing the interlock mechanism that holds the active state is inserted is provided separately from the exhaust hole (vent hole).

Furthermore, in the above embodiment, the description has been given of the case where the small diameter insertion hole for inserting the lead wire is formed in the airbag, but the invention is not limited to such a small diameter insertion hole.
Even when forming various insertion holes having a diameter smaller than the diameter of the lower portion of the inflator, as long as the airbag is sandwiched in a ring shape and double by the base plate and the retainer ring via the flange of the inflator,
It does not depart from the spirit of the invention.

[0045]

As is apparent from the above description, according to the airbag device of the present invention, the airbag can be double clamped and fixed to the entire front and back surfaces of the mounting flange of the inflator by the base plate and the retainer ring. Not only will the installation be strong, but local tensile stress will not act when the airbag is inflated and deployed, so the airbag will not be damaged and the ideal inflation form can be easily realized. Assembling the airbag module is easy, the number of parts can be reduced significantly, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a front view of a steering wheel equipped with an airbag device of the present invention.

FIG. 2 is an exploded perspective view showing a first embodiment of the front steering wheel and the airbag device.

FIG. 3 is a sectional view of the airbag module.

FIG. 4 is a front view showing an example of the overall configuration of the airbag.

FIG. 5 is an exploded perspective view of the airbag before suturing.

FIG. 6 is a perspective view showing an inserted state of the inflator with respect to the airbag.

FIG. 7 is an exploded perspective view of an airbag device and a steering wheel according to a second embodiment of the present invention.

FIG. 8 is a sectional view of the airbag module.

[Explanation of symbols]

 1 Steering wheel 2 Steering wheel body 2d Fixed contact 3 Wheel ring 4 Pad part 5 Boss plate 6 Spoke core metal 7 Guide bolt 8,31 Coil spring 9,35 Movable plate 9a, 35a Mounting tongue 10 Lead wire 20,200 Airbag Modules 21, 210 Base plates 21a, 211 Plate bodies 21b, 212 Side walls 21c, 213 Openings 214 Stud bolts 215 Passage voids 21d Bolt insertion holes 21e, 216 Rivet insertion holes 22 Inflator 22a Gas injection part 22b Lower initiation part 22c Mounting flange 22d Gas Injection hole 23 Air bag cover 23a Mounting frame portion 23b Cleavage portion 23c Tear line 24 Air bags 24a, 24b Upper and lower woven cloth 24c Lead wire insertion hole 24d Unsewn portion 4e opening 25 retaining ring 25a, 214 stud bolt 25c bolt hole 26 nut 30 switching device 32a, 32b vertically insulator 35b flat portion 35c movable contact 40 blind rivet

Claims (5)

[Claims] 1. An inflator having a mounting flange on its peripheral surface for ejecting gas, an airbag inflated by the gas ejected from the inflator, a case body for accommodating the airbag, and the airbag together with the mounting flange. An air bag module including a supporting base plate is provided, and the air bag has a bag shape having no opening for inserting the inflator, and a small diameter hole such as a lead wire insertion hole or an exhaust hole is appropriately formed in a part thereof. An airbag device characterized by: 2. The airbag apparatus according to claim 1, wherein a part of the airbag having an inflator built therein is doubly sandwiched by front and back surfaces of the flange, a peripheral edge of an opening of the base plate and a retainer ring. 3. The airbag device according to claim 1, wherein the inflator is incorporated by previously being inserted into a constituent sheet of the airbag and completely closing an opening thereof. 4. A plurality of stud bolts are provided on either the base plate or the retainer ring, and a bolt insertion hole for inserting the stud bolt is provided on the other side, and the stud bolt and the bolt insertion hole are used for mounting the inflator. The airbag device according to claim 1, wherein the airbag device is provided at a portion located outside the flange. 5. A cavity is formed in a periphery of an opening for inserting the inflator of the base plate, the cavity being required to vertically pass through the mounting flange of the inflator.
The airbag device as described in the above.