JPH07195998A - Inflator case for air bat device - Google Patents

Abstract

PURPOSE:To produce a high-accuracy and high-quality inflator case by welding a plurality of plate materials having different wall thicknesses together to form a blank plate, and by applying drawing to the blank plate. CONSTITUTION:In an air bag device in which a steering wheel is installed on a hub, an inflator case is composed by providing a small-diameter cylindrical part 32, and a pair 1 of bowl-like large-diameter cylindrical parts 36 assembled by facing their opening parts each other. An enhancer and a starter are housed in the small-diameter cylindrical part 32. A gas generating material is housed in a ring shape in each large-diameter cylindrical pad 36. In this case, in forming the inflator case, a blank material 66 is produced by firstly engaging a thick inside disk 62 with a thin outside ring plate 64 to engage the disk 62 in the ring of the ring plate 64, and by applying laser welding along the engaged part. Next, drawing the blank material 66 by means of a press forms the small- diameter cylindrical part 32 in the disk 62, and the large-diameter cylindrical parts 36 in the ring plate 64.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inflator case for inflating a bag body of an airbag device.

[0002]

2. Description of the Related Art For example, an airbag device for a driver's seat is
It is attached to the steering wheel, and the bag body bulges toward the driver in the event of a vehicle collision to protect the driver.

An inflator is used to inflate the bag. As shown in FIG. 4 (arrow F indicates the front of the vehicle), in the inflator, the case 102 includes the small-diameter cylindrical portion 1
04, a pair of large-diameter cylindrical portions 126 and 128 are provided coaxially. The enhancer 106 and the activation device 108 are accommodated in the small-diameter cylindrical portion 104, and the large-diameter cylindrical portion 12
The intermediate diameter cylindrical portion 110 is disposed in each of the reference numerals 6 and 128, the gas generating material 112 is annularly accommodated inside the intermediate diameter cylindrical portion 110, and the coolant 116 and the filter 11 are provided outside.
8 are accommodated in a ring shape.

The starter 108 ignites the enhancer 106 when it detects a sudden vehicle deceleration. When the enhancer 106 is ignited, a spark is emitted from the ignition hole 120 of the small-diameter cylindrical portion 104.
It is transmitted to the gas generating material 112 through the. This allows
The gas generating material 112 burns to generate gas. The generated gas passes through the communication hole 122 of the intermediate-diameter cylindrical portion 110, is cooled by the coolant 116, is purified by the filter 118, and is supplied into the bag body from the gas hole 124 of the large-diameter cylindrical portion 126 to form the bag body. Can bulge.

In the small-diameter cylindrical portion 104, the enhancer 10
Since a high pressure is generated by the ignition of No. 6, the small-diameter cylindrical portion 104 needs to have a wall thickness that can withstand the high pressure. On the other hand, the large-diameter cylindrical portions 126 and 128 have a sufficient thickness to withstand the combustion of the gas generating material. For example, the wall thickness of the small diameter cylindrical portion 104 is 1.
The diameter is about 5 to 2 mm, while the large-diameter cylindrical portion 12
The thickness of 6, 128 is about 1 mm.

As described above, the small-diameter cylindrical portion 10 having different wall thicknesses
4. To obtain the large-diameter cylindrical portions 126 and 128, first, a blank material is pressed, each cylindrical portion is individually drawn, and then the above-mentioned flame transfer holes 120 and the like are punched in each cylindrical portion. It is possible to perform the trimming process of No. 1 and then to weld each of the cylindrical parts in combination.

For example, the small-diameter cylindrical portion 104 is a bottomed cylinder, and the pair of large-diameter cylindrical portions 126, 128 are flanged bottomed cylinders. And the small diameter cylindrical portion 1
The bottom wall of 04 and the bottom wall of the large diameter cylindrical portion 126 of one of the pair of large diameter cylindrical portions are welded (b), and the flanges of the large diameter cylindrical portions 126 and 128 are welded (a). , In addition,
The bottom wall of the other large-diameter cylindrical portion 128 of the pair of large-diameter cylindrical portions is bent along the peripheral wall of the small-diameter cylindrical portion 104 and welded (c) to the small-diameter cylindrical portion 104.

[0008]

By the way, in the above inflator case, each cylindrical portion is formed by press-working a blank material corresponding to the cylindrical portion separately,
After that, as they are combined and welded, if the dimensions and shapes of the formed cylindrical parts vary, the welding route becomes unclear, and if the positional deviation due to the welding of each cylindrical part occurs, welding will occur. Quality is reduced.

In view of the above facts, it is an object of the present invention to provide an inflator case for an airbag device, which can easily improve the processing accuracy and the welding quality.

[0010]

In order to solve the above-mentioned problems, the present invention is formed by a plurality of plate materials in which the thickness of the inner plate material and the thickness of the outer plate material welded to the inner plate material are different. For an airbag device, which is obtained by drawing a formed blank material, and includes an inner tubular portion formed of the inner plate material and an outer tubular portion formed of the outer plate material. It proposes an inflator case.

[0011]

According to the inflator case for an air bag device of the present invention, the blank member is formed by welding a plurality of plate members, and the inner plate member and the outer plate member welded thereto have different wall thicknesses. . A blank material formed by welding plate materials having different wall thicknesses is drawn, and an inner tube portion is formed by the inner plate material, and an outer tube portion is formed by the outer plate material.

For example, when an enhancer is housed in the inner cylinder part and a gas generating material is housed in the outer cylinder part to obtain an inflator for an airbag device, the wall thickness of the inner plate material is increased and the outer plate material is increased. By reducing the thickness of the blank and drawing the blank material, the inner cylinder becomes thick enough to withstand the large pressure associated with the ignition of the enhancer, and the outer cylinder becomes
It is thin enough to withstand the small pressures associated with the combustion of the gas generant.

In an inflator case in which blanks corresponding to the respective cylinders are separately drawn, and then the cylinders are combined and welded, the dimensions and shapes of the cylinders are likely to vary, and the cylinders have different sizes. Although a positional shift easily occurs due to the set at the time of welding, in the present invention, welding is performed before draw forming, and it is possible to obtain a tubular portion having a different wall thickness at the same time by one draw forming, and therefore, easily, The processing accuracy is improved,
Welding quality is improved, and less molds are required.
Good material yield.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An inflator case for an airbag device according to an embodiment of the present invention will be described with reference to FIGS. The arrow F in the figure indicates the front of the vehicle.

As shown in FIG. 2, the airbag device 12 for the driver's seat is attached to the hub 16 of the steering wheel 14,
It is attached via the base plate 18. In this airbag device 12, the bag body 2 is provided in the bowl-shaped cover 20.
2 is folded and accommodated, and gas is supplied from the inflator 24 into the bag body 22, whereby the bag body 22 breaks and expands the bottom wall 26 of the cover 20 and bulges toward the occupant side. ing.

As shown in FIG. 1, in the inflator 24, the case includes a small-diameter cylindrical portion 32 and a pair of large-diameter cylindrical portions 3.
4, 36 are provided. In the small diameter cylindrical portion 32,
An enhancer 38 and a starter 40 are housed so as to face each other in the vehicle front-rear direction, an intermediate-diameter cylindrical portion 42 is arranged in each of the large-diameter cylindrical portions 34, 36, and a gas generating material is placed inside through the intermediate-diameter cylindrical portion 42. 44 is accommodated in an annular shape, and the coolant 4 is provided on the outside.
6 and the filter 48 are respectively housed in a ring shape.

At the time of sudden deceleration of the vehicle, although not shown, the ball in the starting device 40 inertially moves and collides the ignition pin toward the detonator. As a result, the detonator ignites and the enhancer 38 ignites. This spark passes through the flame transfer hole 52 formed in the peripheral wall 50 of the small-diameter cylindrical portion 32 and passes through the gas generating material 3
2, the gas generating material 32 burns to generate gas. The generated gas passes through the communication hole 54 opened in the peripheral wall 54 of the intermediate diameter cylindrical portion 42, is cooled by the coolant 46, is purified by the filter 48, and is then one of the large diameter cylindrical portions. Inside the bag body 22 from the gas hole 60 opened in 34, the small-diameter cylindrical portion 32 is the enhancer 3
It is necessary to withstand the high pressure associated with ignition of No. 8, and the wall thickness is increased. On the other hand, the large-diameter cylindrical portions 34 and 36 only need to withstand the pressure associated with the combustion of the gas generating material 44, and the wall thickness may be small. For example, the wall thickness of the small-diameter cylindrical portion 32 is 1.5 to
The diameter is about 2 mm, whereas the large-diameter cylindrical portions 34, 36
Is about 1 mm thick.

The inflator case requiring the cylindrical portions having different wall thicknesses is obtained as follows.

First, as shown in FIG. 3 (A), a circular plate 62 having a large wall thickness that constitutes an inner plate member and an annular plate 64 having a small wall thickness that constitutes an outer plate member are respectively formed to form a circle. The plate 62 is fitted in the ring of the annular plate 64, and is laser-welded (welded portion is indicated by A) in a circumferential shape along the fitting portion. Thereby, the blank material 66 is obtained.

Next, the blank material 66 is drawn by press working. As a result, as shown in FIG. 3B, the two tubular portions are formed coaxially. That is, the circular plate 62 forms the small-diameter cylindrical portion 32, the annular plate 64 forms the other large-diameter cylindrical portion 36 of the pair of large-diameter cylindrical portions, and the small-diameter cylindrical portion 32 becomes thick and has a large diameter. The cylindrical portion 36 has a thin wall. The small-diameter cylindrical portion 36 is a bottomed cylinder, and the welding portion A is located at the open end of the small-diameter cylindrical portion 36. The large-diameter cylindrical portion 36 is formed by folding back the small-diameter cylindrical portion 36 along the welded portion A (folding portion 78), and is further bent at a plurality of portions to form the bottom wall 78, the peripheral wall 80, and the flange 82.
To form a bottomed cylinder with a flange.

On the other hand, another blank material is pressed,
One large-diameter cylindrical portion 34 of the pair of large-diameter cylindrical portions is obtained by drawing. The large-diameter cylindrical portion 34 is a bottomed cylinder with a flange.

After being molded in this way, a flame transfer hole 52 is bored in the peripheral wall 32 of the small diameter cylindrical portion 32, and the large diameter cylindrical portion 3 is formed.
4 is subjected to trimming processing such as drilling gas holes 60. A male screw 96 is formed on the outer peripheral surface of the folded-back portion 78. The open end of the small-diameter cylindrical portion 32 can be closed by the cylindrical cap 84 screwed with the male screw 96.

After that, the bottom wall 72 of the small-diameter cylindrical portion 32 and the bottom wall 70 of the large-diameter cylindrical portion 34 are overlapped and spot-welded (welding site is indicated by B) to form a pair of large-diameter cylindrical portions 34, 3
The flanges 74 and 82 of No. 6 are overlapped and laser welded (the welded portion is indicated by C).

In this way, the inflator case is obtained. The intermediate-diameter cylindrical portion 42 is also press-formed with another blank material to be drawn into a bottomed cylinder with a flange. The bottom wall 88 of the intermediate diameter cylindrical portion 42 allows the open end of the small diameter cylindrical portion 32 to penetrate therethrough and is joined to the bottom wall 78 of the large diameter cylindrical portion 36, and the flange 90 is the bottom wall of the large diameter cylindrical portion 34. It is joined to 70.

Further, in FIG. 1, reference numeral 92 is an annular support frame for separately supporting the filter 48 and the coolant 46.

According to the above construction, first, the blank 66 is formed.
Is a thick disk 62 on the inside and a thin annular plate 64 on the outside.
Are formed by welding, and then the blank material 56 is formed by drawing to form the small-diameter cylindrical portion 32 as the inner cylindrical portion with the disc 62 and the large-diameter cylindrical portion as the outer cylindrical portion with the annular plate 64. The part 36 is formed.

The small-diameter cylindrical portion 32 has a large thickness corresponding to the thickness of the circular plate 62 to withstand the high pressure caused by the ignition of the enhancer 38, and the large-diameter cylindrical portion 36 has a thin wall corresponding to the annular plate 64. Therefore, it withstands the pressure accompanying the combustion of the gas generating material 44.

In an inflator case in which blanks corresponding to the respective cylinders are separately drawn, and then the cylinders are combined and welded, the dimensions and shapes of the cylinders tend to vary, and the cylinders of the cylinders have different shapes. Although a positional shift easily occurs due to the set at the time of welding, in this embodiment, welding is performed before draw forming, and it is possible to obtain a tubular portion having different wall thickness at the same time by one draw forming, and therefore, easily. The processing accuracy is improved, the welding quality is improved, and the number of forming dies is small, and the material yield is good. Further, complicated forming is facilitated by drawing after welding.

As a laser beam for laser welding, a laser beam suitable for stainless steel welding is preferable (as a material of the inflator case, stainless steel or aluminum can be used, and among them, slenderless is preferable).
A CO ₂ laser (having a wavelength of 10.6 μm) and a YAG laser (having a wavelength of 1.06 μm) are preferable. Conditions such as laser output, focus position, and scanning speed are set appropriately so that when laser light is irradiated, the laser light irradiation portion melts and can be welded. In order to carry out welding continuously, the laser beam may be moved or the article to be welded may be moved. In addition,
Welding is not limited to laser welding, but for example, MIG welding or T welding.
Of course, other welding such as IG welding is also possible.

The present invention is not limited to the above embodiment, but can be variously modified. For example, in the above-described embodiment, the airbag device 12 for the driver's seat has been described, but the present invention is not limited to this, and is also applied to an airbag device for a passenger seat, an airbag for a side collision provided in a door, or the like. It is possible.

Further, in the above embodiment, in order to house the enhancer 38 in the small-diameter cylindrical portion 32 and the gas generating material 40 in the large-diameter cylindrical portion 36, a blank material 66 is used as a thick disk. 62 and an annular plate 64 having a small thickness are formed by welding, and a thick small-diameter cylindrical portion 32 is formed by drawing.
Two inner and outer tubular parts having different wall thicknesses from the thin-walled large-diameter cylindrical part 36 were obtained, but the invention is not limited to this. For example, a blank material, conversely, a thin disk and a thin wall It is also possible to obtain a thin-walled small-diameter cylindrical portion and a thick-walled large-diameter cylindrical portion by draw forming. Furthermore, the number of cylinders and the shape of the cylinders are not limited to those in the embodiment. For example, in order to reduce the number of tubular portions to three, the blank may be formed by welding the disc, the outer annular plate, and the further outer annular plate by welding. It may be. Furthermore,
It is also possible to form a blank material by welding annular plates having different diameters instead of a circular plate to form two large and small annular tubular portions.

Further, in the above-mentioned embodiment, the small-diameter cylindrical portion 32 and the large-diameter cylindrical portion 36 obtained by drawing the circular plate 6 are used.
The welded portion A between 2 and the annular plate 64 is located at the open end of the small-diameter cylindrical portion 32, and the large-diameter cylindrical portion 36 forms the folded-back portion 76 that is folded back along the welded portion A. The bottom wall may be formed as it is without forming the folded portion, and in this case, the position of the welded portion A may be located on the bottom wall side of the large diameter cylindrical portion. is there.

[0033]

According to the inflator case for an airbag device of the present invention, the processing accuracy can be easily increased and the welding quality can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an inflator to which a case according to an embodiment of the present invention is applied, as seen from a direction perpendicular to an axis.

FIG. 2 is a cross-sectional view of the airbag device as seen from the direction perpendicular to the axis.

FIG. 3A is a cross-sectional view of a blank material, and FIG. 3B is a cross-sectional view of a tubular portion obtained by drawing the blank material, as viewed in the direction perpendicular to the axis.

FIG. 4 is a view of an inflator to which a conventional case is applied, viewed from a direction perpendicular to an axis.

[Explanation of symbols]

 12 Airbag Device 24 Inflator 32 Small Diameter Cylindrical Part (Inner Cylinder) 36 Large Diameter Cylinder (Outer Cylinder) 62 Disc (Inner Plate) 64 Annular Plate (Outer Plate) 66 Blank Material

Front page continuation (72) Inventor Yoshihide Sakaguchi Noda 1 Ota, Oguchi-machi, Niwa-gun, Aichi Prefecture Tokai Rika Electric Co., Ltd. (72) Inventor Ichiro Hattori 1 Noda, Oguchi, Oguchi-machi, Niwa-gun, Aichi Prefecture Tokai Rika Electric Co., Ltd. (72) Inventor Minoru Abe No. 1 Noda, Toyota, Oguchi Town, Niwa-gun, Aichi Prefecture Tokai Rika Electric Co., Ltd.

Claims (1)

[Claims] 1. A blank material formed by drawing a plurality of plate materials in which the thickness of the inner plate material and the thickness of the outer plate material to be welded to the inner plate material are different, and the blank material is obtained by drawing. An inflator case for an airbag device, comprising: an inner tubular portion formed by the above; and an outer tubular portion formed by the outer plate member.