JP2020157878A - Airbag - Google Patents

Abstract

To provide an airbag which is excellent in productivity and storability, and suppresses sieve opening at a sewing part when expanding the airbag.SOLUTION: An airbag comprises at least two panels, and is formed into a bag shape by a sewing part at which peripheral edges of respective panels are sewn by a suture thread. At least a part of the sewing part, plural sewing units, which include at least one advancement sewing such that sewing is performed in a direction same as a sewing travel direction and at least one retraction sewing continuous with the advancement sewing such that sewing is performed in a direction opposite to the travel direction, are formed so as to be arranged in the travel direction. The advancement sewing and the retraction sewing included in each sewing unit are so located at least parts thereof are overlapped on each other.SELECTED DRAWING: Figure 2

Description

The present invention relates to airbags.

As a safety device for occupant protection that protects occupants from the impact when a vehicle collides, the installation of an airbag device in a vehicle is widespread. In the past, only airbags for driver's seats and passenger's seats, which were prepared for collisions from the front, were often installed, but in recent years, they are called side airbags and curtain airbags. The number of airbags installed in case of a collision from the side is increasing. In addition, due to the diversification of required safety performance, the shape of the airbag in preparation for a collision from the front has become complicated.

Airbags that prepare for side collisions are required to deploy more quickly due to the close distance between the collision object and the occupants, and the pressure inside the airbag tends to increase in order to obtain sufficient protection performance. .. Therefore, a load is likely to be applied to the sewn portion of the airbag in preparation for a collision from the side, and there is a risk that the seams will expand during deployment and the inflator gas will leak.

In addition, as the shape becomes more complicated, the number of parts forming the airbag increases, and the number of sewing tends to increase accordingly. As a result, the load applied to the sewn portion during deployment has become an issue more than ever.

In response to this problem, Patent Document 1 discloses an airbag in which a seam allowance portion is sewn with a pattern to improve sewing strength.

Further, Patent Document 2 discloses an airbag base fabric in which a functional compound is attached to one side of a woven fabric to enhance the frictional action between the yarns, thereby improving the anti-seam displacement. ..

Further, in Patent Document 3, the sewn portion of the airbag formed by sewing the woven fabric is integrally sewn with an auxiliary woven fabric different from the woven fabric to prevent the opening of the eyes at the time of unfolding. Airbags that can prevent bursts of airbags are disclosed.

Japanese Unexamined Patent Publication No. 5-229393 JP-A-2002-220780 Japanese Unexamined Patent Publication No. 2005-14841

However, the airbags disclosed in the above patent documents have the following problems. First, it is clear that the airbag disclosed in Patent Document 1 needs to be sewn for reinforcement at a position different from the sewing for forming the bag, which causes a decrease in productivity.

Since the base fabric for airbags disclosed in Patent Document 2 is provided with a functional compound that enhances the frictional action between threads, there is a risk that the sewing needle will be worn by the added functional compound.

Further, since the airbag disclosed in Patent Document 3 has a reinforcing woven fabric added, it is inevitable that the weight of the airbag will increase and the sewn portion will become bulky, and the storability of the airbag may deteriorate. There is. In addition, since the reinforced fabric is sewn integrally, it is clear that the productivity is lowered.

Therefore, there is a demand for a technique capable of suppressing opening of eyes (also referred to as misalignment) without deteriorating productivity and storability.

An object of the present invention is to provide an airbag which is excellent in productivity and storability and suppresses opening of stitches at a stitched portion when the airbag is deployed.

The airbag according to the present invention includes at least two panels, and is formed in a bag shape by a suture portion in which the peripheral edges of the panels are sutured with sutures, and the suture is formed on at least a part of the suture portion. A suture unit comprising at least one forward suture that is sutured in the same direction as the forward suture and at least one backward suture that is sutured in a direction opposite to the forward suture and continuous with the forward suture is in the forward direction. A plurality of the forward sutures and the backward sutures included in the respective suture units are arranged so as to overlap at least a part thereof.

In the airbag, in the adjacent suture unit, the forward suture and the backward suture can be arranged so as to overlap each other by 3 or more in total.

In the airbag, each suture unit includes one forward suture and one backward suture, and in the suture unit adjacent to the advancing direction, the advancing direction in the advancing suture. It can be configured so that the rear end on the opposite side and the rear end of the retracted suture are connected.

In the airbag, in each of the suture units, the ratio of the length of the retreating suture to the length of the advancing suture in the advancing direction can be 0.33 to 0.70.

In the airbag, each suture unit can include a plurality of the forward sutures and the retracted suture that is one less than the number of the forward sutures, and in the suture unit adjacent to the traveling direction, the suture unit The tip of the forward suture in the traveling direction and the rear end of the forward suture opposite to the traveling direction can be configured to be connected.

In the airbag, 100 / N is 2.5 or less in the suture where the plurality of suture units are lined up, where N is the total number of the forward suture and the backward suture per 100 mm. be able to.

It is possible to provide an airbag that is excellent in productivity and storability and that suppresses the opening of the stitched portion when the airbag is deployed.

It is a top view which shows one Embodiment of the airbag which concerns on this invention. It is the schematic which shows the 1st pattern A of the suture of a panel. It is the schematic which shows the 1st pattern B of the suture of a panel. It is the schematic which shows the 1st pattern C of the suture of a panel. It is the schematic which shows the 1st pattern D of the suture of a panel. It is the schematic which shows the 1st pattern E of the suture of a panel. It is the schematic which shows the 2nd pattern A of the suture of a panel. It is the schematic which shows the 2nd pattern B of the suture of a panel. It is a figure explaining the force acting on the airbag at the time of deployment. It is a figure explaining the force acting on the airbag at the time of deployment. It is a figure explaining the force acting on the airbag at the time of deployment. It is a figure explaining the force acting on the airbag at the time of deployment. It is a figure explaining the position of the needle hole in sewing which concerns on this invention. It is a figure explaining the position of the needle hole in the conventional sewing.

Hereinafter, embodiments of the airbag according to the present invention will be described. FIG. 1 is a plan view showing an example of an airbag according to the present embodiment.

<1. Overview of airbags>
As shown in FIG. 1, the airbag of the present embodiment has two panels 1 cut into a circle, and a sutured portion in which the peripheral edges of the two panels 1 are sewn together with a suture thread 6 is formed. By providing it, it is formed in a bag shape. A mounting port 2 is formed in the center of one of the panels 1, and an annular first reinforcing patch 4 is attached to the panel 1 so as to surround the mounting port 2. The first reinforcing patch 4 is sewn to the panel 1 by suture threads 7a and 7b at two positions arranged concentrically to reinforce the attachment port 2. Further, in this panel 1, two vent holes 3 smaller than the mounting port 2 are formed outside the mounting port 2 in the radial direction. Then, similarly to the attachment port 2, each vent hole 3 also has an annular second reinforcing patch 5 sewn to the panel 1 by the suture thread 7c to reinforce the vent hole 3.

The two panels described above, the first reinforcing patch 4, and the second reinforcing patch 5 are formed of woven pieces cut from a woven fabric for an airbag using a laser cutting machine or a knife cutting machine. The above-mentioned configuration is an example of the simplest shape. If the shape is complicated, three or more panels are joined to form a bag shape, and a belt, which is a woven fabric piece for adjusting the shape, is joined. It can be selected according to the requirements for occupant protection. Further, the shape of the panel 1, the shapes of the reinforcing patches 4 and 5, the shape and the position of the mounting port 2 and the vent hole 3 can be appropriately changed according to the application. Further, the reinforcing patches 4 and 5 are not essential, and may be provided as needed.

<2. Suture>
As described above, in the airbag of the present invention, the panels 1 are joined by stitching, and the stitching is lock stitching, double chain stitching, one-sided stitching, overlock stitching, safety stitching, zigzag stitching, and flat stitching. It can be done by the sewing method applied to ordinary airbags such as. The number of hand movements can be 2 to 10 needles / cm.

Then, in the present invention, the sutured portion is formed by advancing and retracting at least a part thereof. The suture formed by advancing and retreating has suture overlap (overlap in the overlapping direction of the panel 1), which improves the suture strength and makes it possible to suppress the opening. For this reason, when such forward and backward sutures are formed only on a part of the entire suture portion, it is preferable to form the sutures at a position where the load is high when the airbag is deployed. Here, advancing means advancing in the advancing direction of the suture, and retreating means advancing in the direction inverted by 180 degrees with respect to the advancing direction of the suture.

It is imperative that the suture formed by advancing and retreating have two or more repeating units (also referred to as suture units). By having the repeating unit, the load at the time of deployment is evenly applied to the corresponding sutured portion (without bias), and the occurrence of local opening can be suppressed. As a result, airbag burst can be prevented. The opening means that the needle hole (distance between adjacent warp or weft) of the suture is expanded by expanding the panel 1 when the airbag is deployed. The pattern of the suture unit can be arbitrarily selected, but two patterns, that is, a first pattern and a second pattern, are shown below as examples.

<2-1. 1st pattern>
As shown in FIGS. 2 to 6, five types of patterns (first patterns A to E) are shown as the first pattern. First, the first pattern A will be described. In the following, it is assumed that the suture progresses from the left side to the right side in each figure (progress direction), the suture from the left side to the right side is referred to as an forward suture, and the suture from the right side to the left side is referred to as a backward suture. Numbers will be assigned in order of direction. For example, in the first pattern A shown in FIG. 2, the leftmost forward suture is referred to as the first forward suture 811 and the rightmost forward suture is referred to as the fifth forward suture 815. This point is the same for the retracted suture. Further, the right side of each figure is referred to as the "tip" side, and the left side is referred to as the "rear end" side. Further, in the figure showing each pattern, a plurality of suture units are described by shifting them in the vertical direction of the drawing, but this is for convenience of explanation, and in reality, the suture units adjacent to each other in the front and rear are panel 1. It is sewn so that it overlaps in the thickness direction of. At this time, as a general rule, the adjacent suture units are overlapped so as to pass through the same needle hole in the vertical direction, but may be overlapped so as to pass through another needle hole or be displaced in the surface direction to some extent. .. This point is the same for all patterns according to the present invention.

As shown in FIG. 2, in the first pattern A, the length of each forward stitch and each backward stitch is the same, and after each forward stitch 81 to 815, the recess is 25% of the length of the forward stitch 81 to 815. Sutures 911 to 915 are performed, and this is repeated as one unit. Here, the length of the backward stitches 911 to 915 with respect to the length of the forward stitches 81 to 815 is referred to as a pitch ratio, and in the first pattern A, the pitch ratio is 0.25. Further, in this example, by arranging a plurality of units side by side, a maximum of three forward stitches 81 to 815 and backward stitches 911 to 915 are overlapped.

FIG. 3 shows the first pattern B. The difference between the first pattern B and the first pattern A is the pitch ratio, and in the first pattern B, the pitch ratio is 0.33. Further, also in the first pattern B, the forward stitches 821-825 and the backward stitches 921-925 overlap at most three.

FIG. 4 shows the first pattern C. The difference between the first pattern C and the first pattern A is the pitch ratio, and in the first pattern C, the pitch ratio is 0.5. Further, also in the first pattern C, the forward stitching 831 to 835 and the backward stitching 931 to 935 overlap at most three.

FIG. 5 shows the first pattern D. The difference between the first pattern D and the first pattern A is the pitch ratio, and in the first pattern D, the pitch ratio is 0.66. Further, in the first pattern D, a maximum of five forward stitches 843 to 845 and backward stitches 941-945 overlap.

FIG. 6 shows the first pattern E. The difference between the first pattern E and the first pattern A is the pitch ratio, and in the first pattern E, the pitch ratio is 0.7. Further, in the first pattern D, a maximum of seven forward stitches 843 to 845 and backward stitches 941-945 overlap.

The five types of first patterns have been described above, but in the first pattern, one forward stitch and one backward stitch form one unit. The pitch ratio is not particularly limited, but is, for example, preferably 0.33 to 0.70, more preferably 0.50 to 0.66, and further preferably 0.50 to 0.60. When the pitch ratio is 0.33 or more, the overlapping portion of the sutures occupies 50% of the sutures, so that the opening of the stitches can be expected to be suppressed. That is, as the number of overlaps increases, the opening suppression effect improves. On the other hand, if the number of overlaps is too large, the storability is lowered. On the other hand, when the pitch ratio is 0.66 or less, the maximum number of sutures that overlap is 5 or less, and excellent storability can be obtained. From the above, when the pitch ratio is 0.50, the number of sutures overlapping is three, which is the best in terms of suppressing opening and storing.

<2-2. Second pattern>
Next, the second pattern will be described. As shown in FIGS. 7 and 8, two types of patterns (second patterns A and B) are shown as the second pattern. As shown in FIG. 7, in the second pattern A, the forward stitch, the backward stitch, and the forward stitch are continuously performed in this order in one suture unit. That is, in one suture unit, two forward stitches and one backward stitch are performed, and these sutures are the same length. Therefore, the maximum overlap is 3. Then, when the suturing of one suturing unit is completed, the formation of the next suturing unit is started. In the second pattern A, the lengths of the forward stitch and the backward stitch are the same, but the pitch ratio is 0.5 because one stitch unit includes two forward stitches and one backward stitch.

Next, the second pattern B will be described. As shown in FIG. 8, the second pattern B differs from the second pattern A in that the lengths of the two forward stitches 871 and 872 in one suture unit are longer than the length of the backward stitch 971. Is. Therefore, in one suture unit, the tip of the second forward suture is located more anterior than the tip of the receding suture. In the example of the second pattern B shown in FIG. 8, the length of both forward stitches is twice as long as that of the backward stitches, so that the pitch ratio is 0.25. The lengths of the forward stitch and the backward stitch included in one suture unit can be appropriately changed. Further, the lengths of the two forward sutures included in one suture unit may be different.

Although the two patterns have been described above, these patterns can be appropriately combined in the suturing of the peripheral edges of the panels 1. That is, the number of each pattern and the order of combinations are not particularly limited. It is also possible to combine a sutured portion having only forward suture. The number of stitches (the portion between the needle holes adjacent to each other in the traveling direction) included in each forward stitch and each backward stitch is not particularly limited and may be 1.

Further, in the sutures between the panels 1, the average suture pitch of the sutures formed by the forward suture and the backward suture is preferably 2.5 mm or less, more preferably 2.0 mm or less, still more preferably 1. It is 5.5 mm or less. The average suture pitch is a value calculated by counting the total number of forward and backward sutures included in a 100 mm suture and dividing 100 mm by the total number.

For example, if the number of forward stitches is 20 and the number of backward stitches is 10 within 100 mm, the number of stitches is counted as 30, 100/30 = 3.3, and the average stitch pitch is 3.3 mm. Become. As described above, when the average stitch pitch is 2.5 mm or less, the opening of the eyes when the airbag is deployed can be further suppressed. Here, the average stitch pitch is a value calculated by counting the number of stitches (between needle holes) included in a 100 mm stitch and dividing 100 mm by the number of stitches.

<2-3. Sewing thread>
The sewing thread used for suturing may be appropriately selected from those generally called synthetic fiber sewing threads and those used as industrial sewing threads. For example, there are nylon 6, nylon 66, nylon 46, polyester, high molecular weight polyolefin, fluorine-containing, vinylon, aramid, carbon, glass, steel and the like, and it may be any of spun yarn, filament twisted yarn or filament resin processed yarn. The thickness of the suture is not particularly limited, but can be, for example, 700 dtex (equivalent to 20th count) to 2800 dtex (equivalent to 0 count).

The suture described in the present invention is applied to the joining of cut pieces, mainly to the joining of panels, which is a part where a load is applied when the airbag is deployed, but the sewing of an airbag having a belt for adjusting the shape of the airbag. In this case, a high load is also applied to the joint portion between the panel and the belt, so the suture of the present invention may be applied. Further, it may be applied to other parts such as joining a panel and a patch.

<3. Various physical properties of airbags>

The woven fabric used for the airbag of the present invention preferably has a cover factor of 2000 to 2800, more preferably 2200 to 2650. Within this range, excellent strength, low air permeability, flexibility, productivity, and smoothness can be obtained. The cover factor (CF) is defined as follows. The cover factor (CF) is obtained by the product of the weaving density N of each of the warp and weft of the woven fabric and the total fineness D, and is expressed by the following formula.
CF = Nw × √Dw + Nf × √Df
Here, Nw and Nf are the weaving densities of the warp and the weft (book / 2.54 cm), and Dw and Df are the total fineness (dtex) of the warp and the weft.

The total fineness of the threads constituting the woven fabric used for the airbag of the present invention is preferably 310 dtex or more. When the total fineness of the yarn is 310 dtex or more, the strength of the woven fabric becomes an excellent level as an airbag. Further, in terms of easily obtaining a lightweight woven fabric, the total fineness is preferably 560 dtex or less, and more preferably 470 dtex or less.

The air permeability of the woven fabric used for the airbag of the present invention is preferably 0.5 ml / cm ² · sec or less, and 0.3 ml / cm ² · sec or less, as measured by the Frazier method. Is more preferable. By setting the above values, gas leakage from the surface of the base cloth is reduced when the airbag is deployed, and the inflator can be miniaturized and quickly deployed. The air flow rate under a differential pressure of 20 kPa is preferably 0.9 L / cm ² · min or less. With such an amount of airflow, the airbag can be deployed without losing the gas ejected from the inflator. It is also possible to obtain a deployment speed suitable for quickly protecting the occupants.

The single fiber fineness of the yarn constituting the woven fabric may be the same or different, and is preferably in the range of 1.0 to 7.0 dtex, more preferably 1.0. ~ 3.5. If the single fiber fineness is 7.0 dtex or less, there is no effect when the airbag is folded, and if it is 3.5 dtex or less, the flexibility of the woven fabric is improved, the foldability of the airbag is improved, and the air permeability is improved. It can also be lowered. In addition, since single fiber breakage is unlikely to occur in the spinning process, weaving process, etc., the value is preferably 1.0 dtex or more.

The cross-sectional shape of the single fiber may be selected from circular, elliptical, flat, polygonal, hollow, and other variants. If necessary, these mixed fibers, synthetic yarns, combined yarns, mixed yarns (different for warp yarns and weft yarns) may be used, and are appropriately selected within a range that does not interfere with the spinning process, the woven fabric manufacturing process, or the physical properties of the woven fabric. do it.

Various additives commonly used to improve spinnability, processability, durability, etc., such as heat-resistant stabilizers, antioxidants, light-resistant stabilizers, anti-aging agents, and lubricants are added to these fibers. , Smoothing agents, pigments, water repellents, oil repellents, concealing agents such as titanium oxide, gloss imparting agents, flame retardants, plasticizers and the like may be used alone or in combination of two or more.

The structure of the woven fabric may be plain weave, diagonal weave (basket weave), lattice weave (ripstop weave), twill weave, ridge weave, leno weave, imitation weave, or a composite structure thereof. If necessary, in addition to the biaxial warp and weft, a multi-axis design including an oblique angle of 60 degrees may be used, and the arrangement of the threads in this case may be the same as that of the warp or weft. Of these, plain weave is preferable because it can ensure the fineness of the structure and the uniformity of physical properties and performance.

The woven fabric used for the airbag of the present invention is preferably a non-coated cloth, but a part or all of the cut pieces constituting the airbag are coated depending on the output of the inflator and the temperature of the gas generated from the inflator. A cloth may be applied. If it is a non-coated cloth, it is possible to obtain an airbag that is excellent in weight reduction and storability.

The airbag of the present invention includes various occupant protection bags, for example, front collision protection for driver's seat and passenger's seat, side bag for side collision protection, center bag, and rear seat occupant protection (front collision, rear collision). ), Headrest bag for rear collision protection, knee bag and foot bag for leg / foot protection, mini bag for infant protection (child seat), bag for air belt, passenger car for pedestrian protection, commercial car, In addition to various uses such as buses and motorcycles, it can be applied to various uses such as ships, trains / trains, airplanes, and amusement park facilities as long as it is functionally satisfactory.

<4. Features>

Since the airbag of the present invention configured as described above is sewn between panels by a sewing unit including at least one forward stitch and backward stitch, the airbag is opened without applying a reinforcing woven fabric or the like to the stitched portion. Suppression is possible. This point will be described in detail.

First, when the airbag is deployed, a force acts as shown in FIG. 10 and 11 are views showing a state in which the front surface side of the panel and the seam allowance are straightened for convenience of explanation. In FIG. 10, as an example, it is assumed that a force is generated in the direction in which the warp threads extend. As a result, the adjacent weft threads are separated from each other at the place where the suture threads are sewn, and as a result, opening occurs. At the same time, on the seam allowance side, the weft threads are displaced and the intervals between the weft threads are narrowed.

On the other hand, in the present embodiment, since the forward stitch and the backward stitch are combined and the panels are firmly sewn together, the base cloth becomes difficult to move when a force is applied, and as a result, the opening is suppressed. be able to.

Further, since the forward stitch and the backward stitch are overlapped, the stitch pitch becomes narrow. For example, in the example of FIG. 11A, a force is received by 6 sutures against the acting force F, but in the example of FIG. 11B, a force is received by 11 sutures against the acting force F. There is. As a result, in the example of FIG. 11B as in the present embodiment, the acting force acting on each suture is dispersed, whereby the opening of the stitch can be suppressed.

Further, in the present invention, since the forward stitch and the backward stitch are repeatedly performed under predetermined conditions, it is easy to align the pitch of the stitches. Therefore, for example, as shown in FIG. 12A, sewing can be controlled so that the pitches of the stitches are aligned, whereby sewing can be performed using the same needle hole Z. Therefore, since sewing can be performed without increasing the number of needle holes, it is possible to suppress a decrease in the strength of the panel and realize strong sewing. Note that FIG. 12A is described with reference to the example of FIG. On the other hand, if the sewing is simply repeated a plurality of times, the positions of the needle holes may shift as shown in FIG. 12B. Therefore, in each of the first to third sewings, different needle holes Z are formed. May be formed. That is, since a large number of needle holes Z are formed in the panel, the strength of the panel is lowered, and even if sewing is performed a plurality of times, the strength may be lowered. Therefore, according to the airbag according to the present invention, it is possible to provide strong sewing.

1 Panel 810-815, 821-825, 833-835,845,845,851-855,861-876 Forward suture 911-915, 921-925,931-935,941-945,951-955,961-965 , 971-973 Retreat suture

Claims (6)

With at least two panels
The peripheral edges of the panels are formed in a bag shape by the sutured portions that are sutured with sutures.
At least a part of the suture portion is sewn in the same direction as the traveling direction of the suture, and at least one retreat that is sewn in the direction opposite to the traveling direction and is continuous with the advancing suture. A plurality of suture units including sutures are arranged in the traveling direction.
An airbag in which the forward suture and the backward suture included in each suture unit are arranged so as to overlap at least a part thereof. The airbag according to claim 1, wherein in the suture unit adjacent to the suture portion, the forward suture and the backward suture are arranged so as to overlap each other in a total of 3 or more. Each suture unit includes one forward suture and one backward suture.
The suture unit adjacent to the traveling direction, according to claim 1 or 2, wherein the rear end of the advancing suture on the side opposite to the advancing direction and the rear end of the retracting suture are connected. Airbag. The airbag according to claim 3, wherein in each of the suture units, the ratio of the length of the retreating suture to the length of the advancing suture in the traveling direction is 0.33 to 0.70. Each suture unit includes a plurality of the forward sutures and the retracted suture, which is one less than the number of the forward sutures.
The first or second aspect of the suture unit adjacent to the advancing direction, wherein the tip of the advancing suture in the advancing direction and the rear end of the advancing suture opposite to the advancing direction are connected. Airbag. In the suture, where the plurality of suture units are lined up, 100 / N is 2.5 or less when the total number of the forward suture and the backward suture per 100 mm is N, claims 1 to 5. Airbags listed in any of.