JPH09323604A - Air bag for occupant restraint device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify manufacturing process and reduce production cost of an air bag for an occupant restraint device. SOLUTION: An air bag is made in a bag shape by joining together peripheral portions of base cloth pieces 1 and 2 and an exhaust port 4 is provided for discharging at least part of high pressure gas supplied to the interior thereof. The exhaust port 14 is formed by intermittently sewing the peripheral portions of the base cloth pieces 1, 2, or by partially increasing the sewing pitch on the peripheral portions of the base cloth pieces 1, 2, so that parts of the peripheral portions of the base cloth pieces 1, 2 are not joined together. In particular, the parts to be the exhaust port is sewn with a thread which may be broken by an internal pressure of the air bag.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air bag for deploying and inflating by a high pressure gas supplied from an inflator which generates combustion gas when a collision impact is sensed and restraining an occupant.

[0002]

2. Description of the Related Art An occupant restraint system is known in which an inflator generates a combustion gas when a collision impact is sensed, and the high-pressure gas instantly expands and inflates an airbag to restrain the movement of an occupant. . The airbag used for this is to release a part of the high-pressure gas generated by the inflator in order to restrain the occupant's body with appropriate flexibility when inflated and to prevent the occupant from bouncing in the opposite direction. The internal pressure rise / fall characteristics are optimized (see Japanese Patent Publication No. 4-17811).

[0003]

In such an airbag for an occupant restraint system, conventionally, an exhaust port for discharging high-pressure gas is formed by cutting a hole of a predetermined shape in a base cloth forming the airbag. Was there. For this reason, in addition to the step of opening the hole, a step of sewing a reinforcing cloth to the peripheral portion of the hole is required, resulting in a disadvantage that the manufacturing process becomes complicated and the manufacturing cost increases.

[0004]

In order to solve the above problems and reduce the manufacturing cost, in the present invention, the peripheral portions of a plurality of base cloths are joined together to form a bag. In addition, the airbag for an occupant restraint device provided with an exhaust port for discharging at least a part of the high-pressure gas supplied to the inside, wherein the exhaust port is
The non-bonding portion is provided in a part of the peripheral edge portion of the plurality of base cloths.

Particularly, it is preferable that the exhaust port is formed by intermittently stitching the peripheral edges of the plurality of base cloths.

Further, it is preferable that the seam pitches of the peripheral portions of the plurality of base fabrics are partially increased, and the exhaust port is formed at the portion where the seam pitch is large.

In addition to this, it is preferable to sew the portion to be the exhaust port with a thread that can be broken by internal pressure.

Further, it is preferable that ear pieces extending from the outer peripheral edge of the base cloth and folded back inward when they are overlapped with each other are provided in the portion serving as the exhaust port.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of the present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings.

FIG. 1 shows a situation in which an air bag for a driver seat constructed according to the present invention is deployed and inflated. As shown in FIG. 2 as well, this airbag 1 is formed into a bag shape by sewing the peripheral portions of a pair of front and back base cloths 2 and 3 cut into a predetermined circular shape to each other over substantially the entire circumference. In the normal state, the high-pressure gas from the inflator, which is stored in a folded state inside the steering wheel pad in response to a signal from the collision detection means, is provided on the backside base cloth 3. It is supplied from the hole and expanded and expanded.

There are a pair of left and right sides of the airbag 1 that are not sewn to each other over a predetermined size, and the high pressure gas is supplied to the inside to expand and inflate the airbag 1. The sewn portion is expanded to serve as an exhaust port 4 for appropriately discharging high-pressure gas.

On both sides of the exhaust port 4, reciprocal stitching is performed over a predetermined dimension in order to prevent loosening and breaking of the suture thread 5, as shown in FIG.

4 to 8 show a modification of the airbag 1 according to the present invention. What is shown in FIG.
As shown in FIG. 5, the non-sewn portion extending over a predetermined size constitutes the exhaust port 4, and in the exhaust port 4, the outside of the seam by the suture thread 5 is the seam. The sewn yarn 6 having a small tensile strength is sewn over a predetermined size so that both ends overlap with each other. As a result, the exhaust port 4 is closed at the initial stage of inflation, but when the internal pressure of the airbag 1 rises above a predetermined value, the broken yarn 6 naturally breaks and the exhaust port 4 opens. High-pressure gas is not discharged more than necessary when the bag 1 is deployed, and the internal pressure is prevented from becoming insufficient.

FIG. 5 shows that the stitch pitch of the suture thread 5 is
The peripheral edges of the pair of base cloths 2 and 3 are sewn over the entire circumference so that the base cloths 2 and 3 are enlarged at a plurality of positions at regular intervals. The part where these stitch pitches are made larger than others,
Similar to the above-mentioned unsewn portion, the airbag expands and becomes the exhaust port 4 as the airbag expands and expands. In addition, the exhaust port 4 is the same as that shown in FIG.
Both sides of the portion to be used may be reinforced by reciprocating stitches. In addition, as in the case shown in FIG.
It is also possible to sew only the portion to be sewn with the breaking thread 6, and in this case, it is desirable to provide the seam of the breaking thread 6 inside the seam of the suture thread 5.

FIG. 6 shows that ear pieces 7 are formed outward in the radial direction on the outer peripheral edges of the base cloths 2 and 3 to form the exhaust ports 4. As shown in FIG. It is designed to be folded inward and sewn. The ear piece 7 is formed on either or both of the pair of base fabrics 2 and 3, and is sewn by reciprocating stitches to reinforce the peripheral portion of the exhaust port 4.

FIG. 8 shows a situation in which the passenger airbag constructed according to the present invention is deployed and inflated. The airbag 8 includes a pair of substantially triangular base fabrics 9 that are symmetrical to each other.
And a strip-shaped base fabric 10 in total, and in a normal state, they are stored in a folded state inside a lid 11 provided on an instrument panel in front of the passenger seat.

The left and right base cloths 9 and the center base cloth 10 are sewn over substantially the entire circumference, but the upper portion near the base end is not partially sewn, and this non-sewn portion is Similar to the airbag 1 described above, it expands and becomes the exhaust port 4 as it expands and inflates.

Needless to say, the peripheral edges of the plurality of base fabrics may be joined not only by the above-mentioned stitching but also by using an appropriate adhesive.

[0019]

As described above, according to the present invention, a part of the peripheral edge portions of the base cloth, which are conventionally joined to each other by firmly stitching so as to be kept airtight against the internal pressure, are separated from each other. By not connecting them or by connecting them lightly so that they can be easily separated from each other by the internal pressure, the portions are expanded to form an exhaust port as the airbag expands and expands. This saves the labor of cutting out the hole to be the exhaust port in the base cloth and sewing the reinforcing cloth, and simplifies the manufacturing process, which is extremely effective in reducing the manufacturing cost. In addition, since the base cloth itself is not processed, the strength of the base cloth is uniformly maintained over the entire surface, and the advantage of facilitating the design of the airbag is obtained.

As described above, as the structure in which the exhaust port is opened at the peripheral portion of the base fabric in response to the expansion and inflation of the airbag, intermittent stitching is performed or the stitch pitch is partially increased. You can easily get it. That is, when the peripheral edge portion of the base cloth is intermittently sewn, the sewn portions of the peripheral edge portion of the base cloth are bonded to each other to maintain an airtight state, while the non-sewn portion expands in accordance with the expansion and inflation of the airbag. It opens and becomes an exhaust port for discharging high-pressure gas. Further, if the stitch pitch is partially increased, the portion where the stitch pitch is increased expands in accordance with the expansion and inflation of the airbag and becomes an exhaust port. In this way, the exhaust port can be formed extremely easily, which is very effective in reducing the number of manufacturing steps.

Moreover, since a large number of exhaust ports can be formed relatively easily, the opening area of each exhaust port is made small and the influence of the change of the opening area of the exhaust port on the change of the shape of the airbag at the time of inflation is made small. It is possible to obtain stable exhaust characteristics.

Further, by suturing the portion of the exhaust port with a thread that can be broken by the internal pressure, it is possible to prevent the high-pressure gas from being excessively discharged when the airbag is deployed.

In addition to the above, if ear pieces that are folded back inward at the time of stacking are provided so as to project at the portion of the outer peripheral edge of the base cloth that forms the exhaust port, the effort of sewing a separate reinforcing cloth is required. It is possible to easily reinforce the peripheral edge portion of the base cloth, which serves as the exhaust port, without requiring.

[Brief description of drawings]

FIG. 1 is a perspective view showing a deployed and inflated state of an airbag for a driver's seat constructed according to the present invention.

FIG. 2 is a front view of the airbag shown in FIG.

FIG. 3 is an enlarged front view showing a peripheral portion of an exhaust hole.

FIG. 4 is an enlarged front view showing a main part of a first modified embodiment of an airbag constructed according to the present invention.

FIG. 5 is a front view showing a second modification of the same.

FIG. 6 is a front view showing a base cloth before suturing according to a third modified embodiment.

FIG. 7 is a front view showing a completed state after the suturing of the modified form shown in FIG. 6;

FIG. 8 is a perspective view showing a deployment state of an airbag for a passenger seat constructed according to the present invention.

[Explanation of symbols]

 1 Airbag 2.3 Base cloth 4 Exhaust port 5 Suture thread 6 Broken thread 7 Ear piece 8 Airbag 9/10 Base cloth 11 Lid

Claims (5)

[Claims] 1. An occupant, which is formed into a bag shape by joining peripheral portions of a plurality of base cloths to each other and is provided with an exhaust port for discharging at least a part of high-pressure gas supplied to the inside. An airbag for a passenger restraint device, wherein the exhaust port is formed by providing a non-coupling portion at a part of a peripheral portion of the plurality of base fabrics. 2. The airbag for an occupant restraint apparatus according to claim 1, wherein the exhaust port is formed by intermittently stitching the peripheral edges of the plurality of base cloths. 3. The exhaust pitch is formed at a portion where the seam pitch is large by partially enlarging the seam pitch at the peripheral edges of the plurality of base fabrics. An airbag for an occupant restraint system as described above. 4. The airbag for an occupant restraint system according to claim 1, wherein a portion that becomes the exhaust port is sewn with a thread that can be broken by internal pressure. 5. An ear piece that extends from the outer peripheral edge of the base cloth and that is folded back inward when the base cloth is overlapped with each other is provided in a portion that serves as the exhaust port. An airbag for an occupant restraint device according to any one of 1.