JPH11115665A - Air bag folding method for occupant protection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple method capable of obtaining a similar effort even if no expansion regulating member such as complex strings and the like is used, and even if no development regulating member such as an inner bag is used. SOLUTION: This invention is concerned with a folding method for a circular shaped air bag 1 for an occupant protection device, which comprises the peripheral parts of overlapped fabrics sewn together where a surface side backing fabric 2 is overlapped on a back side backing fabric 3 having a gas generator mounting port 3a. In this case, the air bag 1 is wound up in a spiral shape while being started from two opposite places of its peripheral part toward to its center part up to the side part of a gas generator 5 so as to allow an intermediate wound-up body 18 to be formed up, which is composed of two wound-up bodies 16 and 17 lined up in parallel while the gas generator 5 is held in between. By letting both the side portions 18a and 18b in its longer direction of the intermediate wound-up body 18, be squeezed and drawn up toward a center line 19 in the longer direction, paired narrow width parts 20a and 20b narrowed in width, are formed around the gas generator 5 in the longer direction at both the sides of it, and the folding method thereby comprises the paired narrow width parts 20a and 20b wound up around the gas generator 5 in a spiral shape in the identical direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for folding an airbag used in an occupant protection system for a vehicle, and more particularly to a method for suppressing inflation of the airbag in the direction of the occupant in an early stage of deployment of the airbag. The present invention relates to a method of folding an airbag which prevents an occupant from being injured by the inflation force of the airbag.

[0002]

2. Description of the Related Art As shown in FIG. 2, a typical structure of a conventional airbag has a front base cloth 2 located on an occupant side and a gas generator mounting opening 3a for mounting a gas generator 5. As shown in FIG. The back base cloth 3 is overlapped, and the peripheral edges of both base cloths 2 and 3 are sewn by sewing lines 4 to form a bag. A gas generator 5 is inserted into the gas generator mounting opening 3a of the back fabric 3 of the airbag 1 and a flange 5b of the gas generator 5 is inserted.
And the peripheral edge 3b of the opening 3a of the backing base cloth 3 are held and fixed to a retainer 7 by fixing means 6 such as bolts so as to be sandwiched by an upper retainer ring 8.

[0003] The airbag 1 is deployed between the occupant and the vehicle body in a very short time by the high-pressure gas rapidly discharged from the gas discharge port 5a of the gas generator 5, and reduces the collision between the occupant and the vehicle body. Things. By the way, the airbag 1
Although it is folded and arranged in the airbag device, this folding is based on the basic idea of selecting a folding method so that the airbag can be easily deployed at the time of deployment. At the time of deployment, the folded state is released rapidly, and the airbag 1 tends to first inflate rapidly and largely as shown by the dotted line in the figure. At this time, a so-called "punching phenomenon" may occur in which the front end portion 1a of the airbag collides with the occupant's face at high speed, thereby causing abrasion on the occupant's face,
If the occupant has a small physique, the occupant may even be violently bounced off.

In order to prevent this, as shown in FIG. 3, an appropriate portion of the central portion of the front side base cloth 2 and the periphery 3b of the gas generator mounting opening of the back side base cloth 3 are fixed by an expansion restricting member 9 such as a string. A measure has been proposed and implemented to prevent the front side fabric 2 from being excessively unfolded forward by coupling.

Another solution is disclosed in Japanese Patent Laid-Open No. 7-149.
There is a system using an inner bag as represented by Japanese Patent Publication No. 199. In this method, as shown in FIG. 4, an inner bag 11 of an appropriate size enough to cover the gas generator 5 is intermittently sewn to the vicinity 3b of the opening of the back side base cloth 3 in the airbag 1. When the airbag 1 is inflated and deployed, first, the inner bag 11 is inflated, and the inner bag 11 is inflated.
The gas is discharged from the gas passage 10 (unsewn portion) formed in the lateral direction of the airbag body into the airbag body.
Thus, a lateral deployment force is always applied to the airbag 1 at the time of deployment, and the inflation of the airbag in the occupant direction is suppressed.

Further, as a system similar to the system shown in FIG. 4, there is a system using an auxiliary bag disclosed in JP-A-8-11659. In this method, an opening serving as a gas passage is perforated in the inner bag 11 itself, and the opening is formed in the outer peripheral portion excluding the upper portion of the gas generator. It is the same as that of FIG.

[0007]

In the prior art, in the method using the expansion restricting member 9 such as a string shown in FIG. 3, the string is sewn to the inner surfaces of the front side base cloth 2 and the back side base cloth 3. There is a need to. For this purpose, the inner and outer base fabrics 2, 3
After sewing, it is necessary to turn over this and work to sew the expansion regulating member 9, and therefore, it is inevitable that the sewing operation becomes complicated, which is a difficulty in production and at the same time This is a major factor that increases the production cost.

In the method using the inner bag 11 as shown in FIG. 4, a base cloth slightly larger than the gas generator 5 is intermittently connected to the gas generator mounting opening peripheral portion 3b of the back side base cloth 3 while being folded. This is a method that is difficult to adopt in a low-price tide with the same point that it is necessary to perform sewing in a complicated manner.

In the method disclosed in Japanese Patent Application Laid-Open No. Hei 8-11659, an opening having a certain area is formed in the inner bag 11 in advance, and the peripheral portion of the inner bag is sewn on the back side fabric 3 in advance. If it is worn, it becomes possible to sew the back side base cloth 3 with the inner bag with the front side base cloth 2, so that the complicated sewing work described above is eliminated. Since the gas to be blown out from the opening having a certain area, the vector in the forward direction (occupant direction) is increased together with the vector in the lateral direction, and the lateral deployment force is larger than that in the method of FIG. Had the problem of becoming smaller.

In any case, the above-mentioned systems are provided with another member having an inflation restricting action on the airbag having the front base fabric 2 and the back base fabric 3 as basic components. And the fundamental problem that costs are inevitable. Therefore, an object of the present invention is to provide a simple measure that can obtain the same effect without using such a complicated expansion restricting member such as a string or a deployment restricting member such as an inner bag.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is characterized by a front-side base cloth and a back-side base cloth having a gas generator mounting opening. Is a method of folding a circular airbag in which the peripheral edge portion is sewn, and from two opposing peripheral portions of the airbag portion toward the center thereof.
After spirally winding up to the side of the gas generator to form an intermediate winding composed of two parallel windings sandwiching the gas generator, the intermediate winding in the longitudinal direction of the intermediate winding is formed. By narrowing both sides of the gas generator toward the center line in the longitudinal direction, a pair of narrow portions having a narrow width are formed on both sides of the gas generator in the longitudinal direction, centering on the gas generator. After that, the pair of narrow portions are spirally wound in the same direction around the gas generator.

According to this folding method, the present invention can easily prevent abnormal forward bulging in the initial stage of airbag deployment without using the deployment regulating members such as the inflation regulating member 9 and the inner bag 11 shown in FIG. It is possible to do.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for folding an airbag according to the present invention will be described below with reference to the drawings. FIG. 1 (A) ~
(H) is a series of folding step diagrams showing a typical folding method of the airbag according to the present invention, and each drawing is a plan view. First, FIG. 1A is a plan view of the airbag 1 before being folded, as viewed from the back, and shows the back side fabric 3.
A gas generator mounting hole 3a is formed in the center of the gas generator, and a gas generator 5 is inserted and arranged in the hole, and is fixed to a retainer by a retainer ring 8, but in the drawing, a method of folding an airbag is shown. Only the parts necessary for the description are shown, and the detailed mounting portions of the gas generator 5 and the retainer ring 8 and the peripheral sewn portions of the front side base cloth 2 and the back side base cloth 3 are omitted. The same applies to the following drawings.

Next, as shown in FIG.
, The peripheral edge 15 on the opposite side to the side where the vent hole 12 of the back side fabric 3 of the airbag 1 is formed,
The gas generator 5 is bent toward the center of the backside fabric 3 with the backside fabric 3 facing inside, as shown in FIGS. (The side of the retainer ring) to form a spirally wound winding body 16.

Subsequently, as shown in FIG.
6 is also spirally wound toward the center from the peripheral portion facing the winding start end 15, and an intermediate winding body 18 comprising a pair of winding bodies 16 and 17 on both sides of the gas generator 5. To form

Next, the intermediate winding body 1 shown in FIG.
8 left and right sides 1 centering on the longitudinal gas generator 5
8A and 18b are squeezed toward the center line 19 in the longitudinal direction as shown in FIG.
0a and 20b are formed. To this end, the back base fabrics 3c, 3d exposed at the center of the left and right side portions 18a, 18b of the intermediate winding body 18 in FIG. The procedure of pulling the two winding bodies 16 and 17 after that is a simple method from the viewpoint of the process.

Subsequently, as shown in FIG. 1G, the narrow portions 20a and 20b on both the left and right sides are spirally wound around the gas generator 5 in the same direction around the gas generator 5, thereby forming the final shape. Is a folded body 22 in which a spiral wound body 21 is formed around the gas generator 5 as shown in FIG.

In the above-described embodiment, the method of spirally winding up the back fabric 3 of the airbag so that the back fabric 3 is on the inside is described. The intermediate winding body 18 shown in FIG. 1E may be formed by winding up. Also, the narrow portions 20a,
20b may be wound around the gas generator 5 in the clockwise direction or around the gas generator 5 in a counterclockwise direction.

The folded body 22 of the airbag folded as described above is incorporated in an airbag module, and its periphery is surrounded by a retainer or a bag cover of the airbag module, so that the shape of the folded body 22 is reduced. Is held.

On the other hand, when the airbag is deployed, the gas ejected from the gas generator 5 causes a reverse process of the folding process to occur basically simultaneously and in parallel, so that the airbag is inflated and deployed instantaneously. In this case, the folded body 22 has two winding bodies 16,
17 and narrow portions 20a, 2 formed by narrowing them.
Since the winding direction of the wound body 21 of 0b is different from each other, the wound bodies 16, 17 and the wound body 21 act as deployment resistance of the airbag, which hinders smooth deployment of the airbag. Become.

As a result, the airbag is unfolded in the forward direction (direction toward the occupant) and in the radial direction while unwinding the spiral of the folded body 22 at the same time. This prevents the "punching phenomenon" such as directly hitting the occupant's face, thus improving the safety of the airbag.

Further, according to the folding method of the present invention, as described above, the deployment speed of the airbag is reduced, so that when the occupant is seated in front of the seat or when the occupant is small,
The folding method of the present invention is also applicable to a case where it is desired to reduce the deployment speed of a conventional airbag in order to protect the airbag from rapid deployment. In this sense, by applying the present invention to an airbag having the deployment regulating member, while regulating forward deployment, the deployment speed is reduced,
It is also possible to protect the occupant sitting in front of the seat or the occupant having a small size from the rapid deployment of the airbag.

According to the airbag folding method of the present invention, only one of the front side fabrics is present above the gas generator 5, and all other parts are folded around the gas generator. However, recent gas generators use a nitrogen-containing organic compound gas generating agent with a high gasification rate instead of the conventional metal azide compound. The amount of gas generating agent required for the gas generation amount is reduced, and as a result, the gas generator is also reduced in diameter, so there is much more space around the gas generator than in the past. It is possible to get. Therefore, if the present invention is applied to an airbag module incorporating a gas generator using a nitrogen-containing organic compound gas generating agent,
The folding method of the present invention can be easily applied without increasing the size of the airbag module as compared with the related art.

[0024]

As described above, according to the present invention, as a measure for preventing the punching phenomenon in the early stage of the airbag deployment, different from the front and back base cloths such as the inflation restricting member and the inner bag as in the prior art. It does not prevent the airbag from inflating forward abnormally by using the body deployment restricting member, but adopts a folding method that prevents smooth deployment when deploying the airbag. Since the front deployment is suppressed, various front deployment regulating members are unnecessary, and the airbag has a simple structure consisting of only the front and back base fabrics.
It is possible to easily prevent the punching phenomenon,
The cost of the airbag is reduced.

The conventional airbag folding method is as follows.
In general, the airbag is folded while being folded in a bellows shape so that the airbag can be easily deployed.In this case, the folding work is complicated since the folding operation is repeated vertically and horizontally. Since only the operation of winding up the airbag from both sides toward the center and subsequently winding the airbag around the gas generator, the folding operation is greatly simplified, and the workability is improved.

Further, according to the folding method of the present invention, since only one front side fabric is present on the upper part of the gas generator, the thickness of the airbag module can be significantly reduced. As a result, the degree of freedom in the design of the steering wheel is widened from the aspect of the design, and the opposition to various tastes of the steering wheel of the customer is factory.

In the conventional folding method, since all the airbags are folded above the gas generator, the folded body is vertically moved (in the thickness direction of the module).
Therefore, in the module assembling process, it is necessary to attach the bag cover to the retainer by pressing down the inflating force of the folded body from above with the bag cover. However, various secondary processes, parts and structures such as means for temporarily fixing the bag cover to the retainer and means for holding the shape of the folded airbag body were required, but the folding method of the present invention requires Since the folded body is only held around the vertical wall of the retainer or the bag cover, there is no need for a temporary fixing means or structure for resisting the expansion of the folded body, and the mounting structure of the retainer and the bag cover is not required. Also, the mounting work is simplified, and the airbag module assembling process can be simplified.

Further, in a collision in which the response of the acceleration sensor is slow for a large part of the collision such as a pole collision, the occupant rapidly moves toward the airbag device due to the inertial force at the time of the collision. When the airbag was rapidly deployed toward the occupant, the occupant could be injured by applying a large impact force.However, in the airbag folded by the method of the present invention, the deployment speed was reduced. Since it is relatively moderate, it is possible to expect secondary effects such as being able to gently receive the occupant. From this viewpoint, by applying the method of the present invention to an airbag using a conventional deployment restricting member, only the deployment speed of the airbag can be maintained without changing the structure of the airbag (without changing production equipment and parts). And the safety of the airbag can be increased.

[Brief description of the drawings]

FIG. 1 is a folding process diagram showing one embodiment of a method for folding an airbag according to the present invention.

FIG. 2 is a conceptual diagram showing a deployed state of a conventional airbag.

FIG. 3 is a conceptual diagram showing a deployed state of an airbag using a conventional front deployment regulating member.

FIG. 4 is a conceptual diagram showing a deployed state of an airbag using a conventional inner bag.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Airbag 2 Front side base cloth 3 Back side base cloth 3a Gas generator mounting hole 4 Sewing line of front side base cloth and back side base cloth 5 Gas generator 5a Gas discharge hole 8 Retainer ring 9 Inflation regulating member 11 Inner bag 16, 17 rolls Upper body 18 Intermediate hoisting body 19 Center line of the intermediate hoisting body 20a, 20b Narrow portion 21 Wound body 22 Folded body of airbag

Claims (7)

[Claims] 1. An occupant protection system comprising: a front base cloth (2) and a back base cloth (3) having a gas generator mounting opening (3a) overlapped with each other, and a peripheral edge thereof is sewn (4). A method of folding a circular airbag (1) for use, comprising: a spiral shape from two opposing peripheral portions of the airbag (1) to the center of the airbag (5) to the side of the gas generator (5). To form an intermediate winding body (18) consisting of two winding bodies (16, 17) arranged in parallel with the gas generator (5) interposed therebetween, and the intermediate winding body (18) The two side portions (18a, 18b) of the gas generator in the longitudinal direction are aligned with the longitudinal center line (1).
By narrowing down toward 9), a pair of narrow portions (20a, 20b) having a reduced width is formed on both sides of the gas generator (5) in the longitudinal direction. Characterized in that the narrow portions (20a, 20b) are spirally wound around the gas generator (5) in the same direction around the gas generator (5). How to fold 2. The back fabric (3) is located inside from two opposing peripheral portions of the airbag (1).
The method for folding an airbag for an occupant protection device according to claim 1, wherein the intermediate winding body (18) is formed by spirally winding up to the side of the gas generator (5) toward the center thereof. 3. The front base fabric (2) is located inside from two opposing peripheral portions of the airbag (1).
The method for folding an airbag for an occupant protection device according to claim 1, wherein the intermediate winding body (18) is formed by spirally winding up to the side of the gas generator (5) toward the center thereof. 4. The airbag (1) according to any one of claims 1 to 3, wherein the airbag (1) comprises only a front side base cloth (2) and a back side base cloth (3) and does not have a deployment regulating member. Method of folding airbag for occupant protection device 5. The occupant protection device according to claim 1, wherein the airbag (1) has an inner bag (11) sewn to the back side fabric (3). How to fold the airbag 6. An inflation restricting member (9) for restricting inflation of the airbag (1), wherein both ends of the airbag (1) are sewn to the front side base cloth (2) and the back side base cloth (3). The method for folding an airbag for an occupant protection device according to any one of claims 1 to 3, comprising: 7. The gas generator (5) uses a nitrogen-containing organic compound-based gas generating agent.
A method for folding an airbag for an occupant protection device according to any one of the above.