JPH07329695A - Internal pressure adjusting device for air bag - Google Patents

Abstract

PURPOSE:To shorten a period of time from the time when the internal/pressure of an air bag reaches a specified value up to the time when a film is ruptured by providing an opening in a place where a part of a sheet is overlapped with vent holes, which is closely attached to the film, combined with an air bag base fabric, and smaller in elongation than the film. CONSTITUTION:Vent holes 5 are provided for the base fabric 8 of an air bag 1, and a film 7 is also provided, which covers the vent holes 5, and is ruptured when gas pressure in the inside of the air bag 1 exceeds a specified value. An opening 11 is provided in a place where a part of a sheet 6 is overlapped with the vent holes 5, which is closely attached to the film 7, combined with the air bag base fabric 8, and smaller in elongation than the film. By this constitution, a period of time from the time when the inner pressure of the air bag reaches a specified value up to the time when the film 7 is ruptured, can thereby be shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air bag of an air bag device provided in an automobile or the like, and more particularly to a device for adjusting an internal pressure of the air bag.

[0002]

2. Description of the Related Art As is well known, an automobile air bag system is constructed so that gas is supplied into the air bag at the time of collision of the car to rapidly deploy the air bag.

When an occupant plunges into the deployed airbag, a vent hole is provided in the airbag to reduce the impact on the occupant by causing the gas in the airbag to flow out of the airbag. There is.

In order to promptly deploy the airbag, the vent hole is closed when the airbag is being deployed, and the vent hole is opened when the internal pressure of the airbag exceeds a predetermined level. Devices are known. FIG. 6 shows a conventional air bag internal pressure adjusting device, in which a vent hole 32 provided in a base fabric 31 of an air bag is provided with a rubber or resin film 33.
The film 33 is broken when the internal pressure of the air bag, which is covered with, exceeds a predetermined value. Reference numeral 34 designates a thread for sewing the film 33 to the base cloth 31.

[0005]

In the conventional air bag internal pressure adjusting device, when the air bag internal pressure rises, the film 33 moves from the vent hole 32 to the outside of the air bag as shown in FIG. It bulges out and then the film 33 breaks. Therefore, from the time when the internal pressure of the airbag reaches a predetermined pressure to the time when the film 33 is broken, the time elapses by the time corresponding to the time when the film 33 bulges.

Particularly, since the seam of the thread 34 is separated from the peripheral portion of the vent hole 32 to a required extent, the film 33 in the region F between the threads 34 extends when the internal pressure of the airbag rises. For this reason, the film 33 swells up considerably from the vent hole as shown in FIG.

An object of the present invention is to provide an internal pressure adjusting device for an airbag, which shortens the time from when the internal pressure of the airbag reaches a predetermined pressure until the film is broken.

[0008]

According to a first aspect of the present invention, there is provided an internal pressure adjusting device for an air bag, the vent hole is provided in a base cloth of the air bag, and the vent hole is covered. In an internal pressure adjusting device for an airbag, which has a film that ruptures when the pressure exceeds a pressure, further, the film is in close contact with the film and is bonded to an airbag base cloth around the vent hole, and It is characterized by comprising a sheet having a small elongation and an opening provided at a position of the sheet which overlaps with the vent hole.

According to a second aspect of the present invention, there is provided an air bag internal pressure adjusting device.
In Claim 1, the opening of the seat is substantially the same size as the vent hole or slightly larger than the vent hole.

According to a third aspect of the present invention, there is provided an internal pressure adjusting device for an air bag.
In Claim 1 or 2, a plurality of vent holes are arranged close to each other, and the vent holes close to each other are covered by one sheet of the film.

According to a fourth aspect of the present invention, there is provided an internal pressure adjusting device for an airbag.
A vent hole provided in a base fabric of an airbag, and a film that covers the vent hole and ruptures when a gas pressure inside the airbag exceeds a predetermined pressure, and an internal pressure adjusting device for an airbag, 10 to 10 diameters
It is characterized in that circular vent holes of 30 mm are arranged close to each other, and these adjacent vent holes are covered with one sheet of film.

[0012]

In the air bag internal pressure adjusting device according to the first aspect, when the air bag internal pressure becomes high, the film tries to bulge out of the air bag from the vent hole.
The sheet having a small elongation is closely attached to the film, and only the opening portion of the sheet of the film can freely extend from the sheet. Therefore, the film ruptures when the bulging of the film to the outside of the vent hole is small.

In the air bag internal pressure adjusting device according to the second aspect, the size of the seat opening is substantially the same as or slightly larger than the vent hole.
The stretch range of the film is narrowed. Therefore, the film ruptures when the bulging of the film to the outside of the vent hole is small.

In the air bag internal pressure adjusting device of the third aspect, even if the opening area of each vent hole is made small, the vent hole opening area required for the entire airbag can be secured. By reducing the size of each vent hole, the stretch range of the film is narrowed. Therefore, the film ruptures when the bulging of the film to the outside of the vent hole is small.

In the air bag internal pressure adjusting device of the fourth aspect, even if the opening area of each vent hole is made small, the vent hole opening area required for the entire airbag can be secured. By making each vent hole small, even a thin film will not burst until the internal pressure of the airbag rises to a predetermined pressure.

[0016]

EXAMPLES Examples will be described below with reference to the drawings. FIG. 1 is a perspective view showing an airbag for a passenger seat according to an embodiment of the present invention, FIG. 2 is a side view of a main part of FIG. 1, and FIG. 3 is a sectional view taken along line III-III of FIG. FIG. 4 is an operation diagram of the vent hole portion.

The passenger seat airbag 1 has an opening 2 at its rear portion for receiving gas from an inflator (not shown). The airbag 1 is made of cloth, and a flap portion 3 is provided on the peripheral portion of the opening 2 by impregnating a synthetic resin or by stitching a reinforcing cloth. The flap portion 3 is provided with a plurality of bolt or rivet insertion holes 4 so that the airbag 1 can be connected to a container (not shown) of the airbag device by the bolts or rivets. On the side surface of the airbag 1, a plurality of circular vent holes 5 are provided close to each other in an array of 3 × 4.

A film 7 and a sheet 6 adhered to the film 7 from the inner surface side of the airbag 1 so as to close the vent hole 5 are sewn to a base cloth 8 of the airbag 1 together with a patch cloth 10 with a thread 9. It is attached. As shown, the seam of the thread 9 extends so as to surround a group of 12 vent holes 5.

The seat 6 and the patch cloth 10 are provided with circular openings 11 and 12 having substantially the same size as the vent hole 5. The film 7 is in close contact with the sheet 6 so as to close the opening 11.

The diameter of the vent hole 5 is preferably 10 to 30 mm, especially 15 to 30 mm. Opening 1 of seat 6
The diameter of 1 is substantially the same as that of the vent hole 5 or slightly larger than the vent hole 5 (for example, within 3 mm).

In this embodiment, the film 7 is arranged between the patch cloth 10 and the sheet 6, but the film 7 may be arranged between the sheet 6 and the base cloth 8.

The film 7 has a thickness of 50 to 300 μm.
m is suitable for silicone rubber, but polyurethane,
Synthetic resins and rubbers such as olefin elastomers and chloroprene rubber are also suitable. As a material for forming the sheet 6, polyester, nylon, olefin resin, or the like is suitable. The elongation of the sheet 6 is preferably 1000% or less, particularly 800% or less of the elongation of the film 7. The film 7 and the sheet 6 are brought into close contact with each other only by stacking them, but they may be adhered to each other with an adhesive.

The passenger seat air bag 1 thus constructed is expanded into the shape shown in FIG. 1 by the gas from the inflator introduced through the opening 2 into the interior. When the gas pressure P in the expanded airbag 1 becomes higher than a predetermined pressure, the film 7 swells outward as shown in FIG. 4, and then the film 7 ruptures so that the vent hole 5 and the opening 11 are inside and outside the airbag 1. Will be in communication with each other. Reference numeral 7t schematically shows a tear that has entered the film 7.

In the present embodiment, since the sheet 6 having a small elongation is in close contact with the film 7, only the portion of the film 7 facing the opening 11 of the film 7 bulges outward of the airbag. Then, when the film 7 is slightly expanded as shown in FIG. 4, the tension applied to the film 7 exceeds the compressive strength of the film 7, and the film 7 is broken.

In this embodiment, since a large number of vent holes 5 having a small diameter are provided, the area of the film 7 facing each vent hole 5 is small. Therefore, even if the film 7 is thin,
The film 7 does not tear until the inner pressure of the airbag reaches a predetermined pressure.

The film 7 preferably breaks when the gas pressure in the airbag 1 reaches a pressure selected from the range of 5 to 70, especially 15 to 50 KPa. The film 7 is ruptured when the pressure inside the airbag 1 reaches the predetermined pressure, and may be ruptured before the occupant thrusts into the airbag 1, or the occupant thrusts into the airbag 1. The pressure inside the airbag 1 may be broken when the pressure exceeds the predetermined pressure.

FIG. 5 is a perspective view of the driver airbag according to the embodiment of the present invention.

The driver airbag 16 of this embodiment has an opening 17 at the center of the rear portion for receiving the inflator. Around the opening 17, a plurality of insertion holes 17a for inserting bolts or rivets are provided.
The airbag 16 is made of cloth and has a rear panel 18 and a front panel 19. The rear panel 18 is provided with a plurality of vent holes 20 adjacent to each other. The vent holes 20 are close to each other. In the vicinity of the vent holes 20, the base fabrics of the airbag 15 are overlapped, and the base fabrics on both sides of the overlapping portion 21 are sewn together with threads.

A film / sheet adhesive laminate 22 is sewn on the back side of the airbag base fabric so as to close the vent hole 20. This sheet has an opening similar to the sheet 6 of the above-mentioned embodiment and the opening is covered with a film.

In the driver seat airbag 15 constructed in this manner, the airbag 15 is also deployed by the gas from the inflator as shown in FIG. When the gas pressure inside the airbag 15 becomes higher than a predetermined pressure, the film slightly swells to the outside of the vent hole 20 and then immediately ruptures to open the vent hole 20.

[0031]

As described above, in the air bag internal pressure adjusting device of the present invention, the vent hole is closed until the pressure in the air bag reaches a predetermined pressure, so that the air bag can be deployed very quickly. Become. Therefore, even if the capacity of the airbag is increased or the output of the inflator is reduced, the airbag can be deployed sufficiently quickly.

In the airbag of the present invention, when the gas pressure inside the airbag becomes higher than a predetermined pressure, the film bulges slightly outward from the vent hole and then immediately ruptures. Therefore, the time from when the internal pressure of the airbag reaches a predetermined pressure to when the film is broken is short.

In the inner pressure adjusting device of the second aspect, since the range in which the film can freely extend can be limited to a very narrow range, the time from when the inner pressure of the airbag reaches a predetermined pressure to when the film breaks. It will be extremely short.

The internal pressure adjusting device for an airbag according to claim 3 is
The sheet can be easily sewn onto the base fabric.

According to the inner pressure adjusting device for an airbag of claim 4, the thickness of the film can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view of a passenger seat airbag according to an embodiment.

FIG. 2 is a side view of a main part of FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a sectional view of a vent hole portion during operation.

FIG. 5 is a perspective view of the driver airbag according to the embodiment.

FIG. 6 is a cross-sectional view showing a conventional example.

FIG. 7 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

 1 Airbag for passenger seat 2 Opening 3 Flap part 5 Venthole 6 Sheet 7 Film 8 Base cloth 9 Thread 11, 12 Opening 16 Airbag for driver's seat 20 Venthole 22 Laminate of seat and film

Claims (4)

[Claims] 1. An airbag comprising: a vent hole provided in a base fabric of the airbag; and a film covering the vent hole and being broken when a gas pressure inside the airbag exceeds a predetermined pressure. In the internal pressure adjusting device, a sheet that is in close contact with the film and is bonded to the airbag base cloth around the vent hole and has a smaller elongation than the film, and a position of the sheet that overlaps the vent hole. An internal pressure adjusting device for an airbag, comprising: an opening provided in the. 2. The internal pressure adjusting device for an airbag according to claim 1, wherein the opening of the seat is substantially the same size as or slightly larger than the vent hole. 3. The airbag according to claim 1, wherein a plurality of vent holes are arranged close to each other, and the adjacent vent holes are covered by one sheet of the film. Internal pressure regulator. 4. An airbag comprising: a vent hole provided in a base fabric of the airbag; and a film covering the vent hole and breaking when the gas pressure inside the airbag exceeds a predetermined pressure. In the internal pressure adjusting device, a plurality of circular vent holes having a diameter of 10 to 30 mm are closely arranged, and these adjacent vent holes are covered by a single film, and the internal pressure adjusting device for an airbag is characterized.