JP7296752B2 - Airbag - Google Patents

Description

The present invention relates to airbags.

2. Description of the Related Art As a safety device for protecting a passenger from impact when the vehicle collides, an airbag device is widely installed in the vehicle. Conventionally, only airbags for frontal collisions, such as driver's airbags and passenger's airbags, were often installed, but in recent years, side airbags and curtain airbags have been installed. The installation of airbags in preparation for side collisions is also increasing. In addition, due to the diversification of required safety performance, the shapes of airbags to prepare for frontal collisions are becoming more complicated.

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

In addition, as the shape becomes more complicated, the number of parts forming the airbag increases, and along with this, the number of stitches tends to increase. As a result, the load applied to the sewn part during unfolding has become an issue more than ever.

In order to solve this problem, Patent Document 1 discloses an airbag in which pattern sewing is applied to seam allowances 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 fabric to enhance the frictional action between yarns, thereby improving anti-misalignment. .

Further, in Patent Document 3, a sewing part of an airbag formed by sewing a fabric is integrally sewn with an auxiliary fabric different from this fabric, which prevents the opening of the eyes when deployed, and An airbag is disclosed that can prevent airbag bursts.

JP-A-5-229393 Japanese Patent Application Laid-Open No. 2002-220780 JP 2005-14841 A

However, the airbags disclosed in the above patent documents have the following problems. First, 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 obviously leads to a decrease in productivity.

The airbag base fabric disclosed in Patent Literature 2 is provided with a functional compound that enhances the frictional action between threads, and the functional compound thus provided may wear the sewing needles.

In addition, since the airbag disclosed in Patent Document 3 has an additional reinforcing fabric, it is inevitable that the weight of the airbag increases and that the sewn portion becomes bulky, which may deteriorate the storability of the airbag. There is Moreover, since the reinforcing fabric is integrally sewn, it is obvious that the productivity is lowered.

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

SUMMARY OF THE INVENTION An object of the present invention is to provide an airbag that is excellent in productivity and storability, and that suppresses the opening of the seams at the time of deployment of the airbag.

An airbag according to the present invention includes at least two panels, and is formed into a bag shape by a sewn portion in which peripheral edges of the panels are sewn together with a suture thread, and at least a part of the sewn portion includes the sewn and at least one receding suture sutured in a direction opposite to said advancing direction and continuous with said advancing suture in said advancing direction. A plurality of the forward stitches and the backward stitches included in each of the stitching units are arranged so as to overlap each other at least partially.

In the above airbag, in the adjacent stitching units, the forward stitches and the backward stitches may be arranged so as to overlap three or more in total.

In the above airbag, each of the stitching units includes one forward stitching and one backward stitching, and the stitching units adjacent to each other in the advancing direction are arranged in the advancing direction in the forward stitching. The trailing end opposite to and the trailing end of the retraction suture may be configured to be connected.

In the above airbag, in each of the stitching units, the ratio of the length of the backward stitching to the length of the forward stitching in the advancing direction may be 0.33 to 0.70.

In the airbag described above, each of the stitching units may include a plurality of forward stitches and the backward stitches that are one less than the number of forward stitches, and the stitching units adjacent in the traveling direction are: The front end of the advancing suture in the advancing direction and the rear end of the advancing suture opposite to the advancing direction may be connected.

In the above-mentioned airbag, in the stitching, the portion where the plurality of stitching units are arranged is such that 100/N is 2.5 or less, where N is the total number of the forward stitching and the backward stitching 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 seams at the seams when the airbag is deployed.

1 is a plan view showing an embodiment of an airbag according to the present invention; FIG. FIG. 4 is a schematic diagram showing a first pattern A of stitching of panels; FIG. 10 is a schematic diagram showing a first pattern B of stitching of panels; FIG. 10 is a schematic diagram showing a first pattern C of stitching of panels; FIG. 11 is a schematic diagram showing a first pattern D of stitching of panels; FIG. 11 is a schematic diagram showing a first pattern E of stitching of panels; FIG. 11 is a schematic diagram showing a second pattern A of stitching of panels; FIG. 11 is a schematic diagram showing a second pattern B of stitching of panels; FIG. 4 is a diagram for explaining forces acting on an airbag during deployment; FIG. 4 is a diagram for explaining forces acting on an airbag during deployment; FIG. 4 is a diagram for explaining forces acting on an airbag during deployment; FIG. 4 is a diagram for explaining forces acting on an airbag during deployment; It is a figure explaining the position of the needle hole in sewing which concerns on this invention. FIG. 10 is a diagram illustrating positions of needle holes in conventional sewing;

An embodiment of an airbag according to the present invention will be described below. FIG. 1 is a plan view showing an example of an airbag according to this embodiment.

<1. Overview of Airbags>
As shown in FIG. 1, the airbag of this embodiment has two panels 1 that are cut in a circular shape. It is formed in a bag shape by providing it. A mounting opening 2 is formed in the center of one panel 1 , and a ring-shaped first reinforcing patch 4 is attached to the panel 1 so as to surround the mounting opening 2 . The first reinforcing patch 4 is sewn to the panel 1 with suture threads 7a and 7b at two concentrically arranged locations to reinforce the mounting opening 2. As shown in FIG. Also, in this panel 1, two vent holes 3 smaller than the mounting opening 2 are formed outside the mounting opening 2 in the radial direction. Similarly to the mounting opening 2, each vent hole 3 has a second annular reinforcing patch 5 sewn to the panel 1 with a suture thread 7c to reinforce the vent hole 3. As shown in FIG.

The two panels described above, the first reinforcing patch 4 and the second reinforcing patch 5, are formed by pieces of fabric cut from airbag fabric using a laser cutter or a knife cutter. The above configuration is an example of the simplest shape, and if it is a complicated shape, it can be made into a bag shape by joining three or more panels, or by joining a belt that is a piece of fabric for adjusting the shape. It can be selected according to the passenger protection requirement. Further, the shape of the panel 1, the shapes of the reinforcing patches 4 and 5, the shapes and positions of the mounting opening 2 and the vent hole 3, etc. can be appropriately changed according to the application. Furthermore, the reinforcing patches 4 and 5 are not essential, and may be provided as required.

<2. Suture>
As described above, in the airbag of the present invention, the panels 1 are joined by stitching. It can be performed by a sewing method applied to ordinary airbags such as. Further, the number of stitches can be set to 2 to 10 stitches/cm.

Further, in the present invention, the sutured portion is formed by advancing and retracting at least a portion thereof. The suturing formed by advancing and retreating has overlapping sutures (overlapping in the direction in which the panels 1 overlap), which increases the suturing strength and makes it possible to suppress the opening of the eyes. For this reason, when stitching by advancing and retreating is formed only in part of the entire stitched portion, it is preferable to form it at a position where the load is high when the airbag is deployed. Here, "advance" means advancing in the suture advancing direction, and "retreat" means advancing in a direction reversed 180 degrees with respect to the suturing advancing direction.

It is essential that sutures formed by advancing and retracting have two or more repeating units (also called suturing units). By having the repeating unit, the load at the time of unfolding is evenly applied to the sutured portion (without unevenness), and the occurrence of local eye opening can be suppressed. As a result, airbag burst can be prevented. Note that the opening means that the needle hole of the suture (the distance between adjacent warps or wefts) expands due to the expansion of the panel 1 when the airbag is deployed. Although the pattern of the suturing unit can be arbitrarily selected, two patterns, ie, a first pattern and a second pattern, are shown below as examples.

<2-1. First 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 explained. In the following, it is assumed that suturing proceeds from left to right in each figure (advancing direction), suturing from left to right is referred to as forward suturing, and suturing from right to left is referred to as backward suturing. The directions are numbered in order. For example, in the first pattern A shown in FIG. 2 , the leftmost forward stitching is called the first forward stitching 811 and the rightmost forward stitching is called the fifth forward stitching 815 . This point is the same for the backward suturing. Also, the right side of each figure is called the "front end" side, and the left side is called the "rear end" side. Furthermore, in the diagrams showing each pattern, a plurality of stitching units are shown shifted in the vertical direction of the drawing. are overlapped and sutured in the thickness direction. At this time, in principle, the adjacent suturing units overlap so as to pass through the same needle hole in the vertical direction. . 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 advancing suture and each retreating suture is the same, and after each advancing suture 811-815, 25% of the length of the advancing suture 811-815 is retreated. Sutures 911 to 915 are performed and repeated as one unit. Here, the length of the backward stitches 911-915 to the length of the forward stitches 811-815 is referred to as the pitch ratio, and in the first pattern A, the pitch ratio is 0.25. Also, in this example, by arranging a plurality of units, up to three forward stitches 811 to 815 and backward stitches 911 to 915 are overlapped.

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

FIG. 4 shows the first pattern C. As shown in FIG. The difference between the first pattern C and the first pattern A is the pitch ratio. In the first pattern C, the pitch ratio is 0.5. Also in the first pattern C, at most three forward stitches 831 to 835 and three backward stitches 931 to 935 overlap.

FIG. 5 shows the first pattern D. FIG. The difference between the first pattern D and the first pattern A is the pitch ratio. In the first pattern D, the pitch ratio is 0.66. Further, in the first pattern D, the forward stitches 841 to 845 and the backward stitches 941 to 945 overlap five at most.

FIG. 6 shows the first pattern E. FIG. The difference between the first pattern E and the first pattern A is the pitch ratio. In the first pattern E, the pitch ratio is 0.7. In addition, in the first pattern D, the forward stitches 841 to 845 and the backward stitches 941 to 945 overlap at most seven.

As described above, the five types of first patterns have been described. In the first pattern, one forward stitch and one backward stitch form one unit. Although the pitch ratio is not particularly limited, it is preferably 0.33 to 0.70, more preferably 0.50 to 0.66, still more preferably 0.50 to 0.60. If the pitch ratio is 0.33 or more, the overlapping portion of the suture thread occupies 50% of the suture, and therefore it can be expected to suppress the opening of the stitches. That is, as the number of overlaps increases, the effect of suppressing opening of the eyes improves. On the other hand, if the number of overlaps is too large, the storability will decrease. On the other hand, if the pitch ratio is 0.66 or less, the maximum number of overlapping sutures is 5 or less, and excellent storability is obtained. From the above, if the pitch ratio is 0.50, the suture thread overlaps three, which is the best from the point of view of restraining the opening and storability.

<2-2. Second pattern>
Next, the second pattern will be explained. 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, forward stitching, backward stitching, and forward stitching are continuously performed in this order in one stitching unit. That is, two forward stitches and one backward stitch are performed in one stitching unit, and these stitches have the same length. So the maximum overlap is 3. Then, when the stitching of one stitching unit is finished, the formation of the next stitching unit is started. In the second pattern A, the forward stitches and the backward stitches have the same length, but one stitch unit includes two forward stitches and one backward stitch, so the pitch ratio is 0.5.

Next, the second pattern B will be explained. As shown in FIG. 8, the second pattern B differs from the second pattern A in that the length of the two forward stitches 871 and 872 is longer than the length of the backward stitch 971 in one stitching unit. is. Therefore, in one suturing unit, the tip of the second forward suture is positioned more forward than the tip of the backward suture. In the example of the second pattern B shown in FIG. 8, the length of both forward stitches is twice the length of the backward stitches, so the pitch ratio is 0.25. The lengths of forward stitching and backward stitching included in one stitching unit can be changed as appropriate. Also, the lengths of the two forward sutures included in one suturing unit may be different.

Although the two patterns have been described above, these patterns can be combined as appropriate when sewing the peripheral edges of the panels 1 together. That is, the number of each pattern and the order of combination are not particularly limited. In addition, it is also possible to combine sutured portions only for forward stitching. Note that the number of stitches (portions between needle holes adjacent in the advancing direction) included in each forward stitching and each backward stitching is not particularly limited, and may be one.

In addition, when the panels 1 are sewn together, the average stitch pitch of the stitches formed by forward stitching and backward stitching is preferably 2.5 mm or less, more preferably 2.0 mm or less, and still more preferably 1 mm. .5 mm or less. The average suture pitch is a value calculated by counting the total number of forward and backward sutures included in 100 mm of suture and dividing 100 mm by the total number.

For example, if 20 forward sutures and 10 backward sutures are included within 100 mm, the number of sutures is counted as 30, 100/30=3.3, and the average suture pitch is 3.3 mm. Become. As described above, if the average stitch pitch is 2.5 mm or less, it is possible to further suppress the opening of the eyes when the airbag is deployed. 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>
Sewing threads used for suturing may be appropriately selected from those generally called synthetic fiber sewing threads and those used as industrial sewing threads. For example, nylon 6, nylon 66, nylon 46, polyester, high-molecular polyolefin, fluorine-containing, vinylon, aramid, carbon, glass, steel, etc., may be spun yarn, filament plied yarn, or filament resin processed yarn. The thickness of the suture thread is not particularly limited, but can be, for example, 700 dtex (corresponding to 20 count) to 2800 dtex (corresponding to 0 count).

The stitching according to the present invention is applied to the joining of pieces to be cut, mainly to the joining of panels, which are parts where a load is applied when an airbag is deployed. In some cases, the stitching of the present invention is preferably applied because a high load is also applied to the joint portion between the panel and the belt. Also, it may be applied to other parts such as the joint between a panel and a patch.

<3. Various Physical Properties of Airbags>

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

It is preferable that the total fineness of the threads constituting the fabric used for the airbag of the present invention is 310 dtex or more. When the total fineness of the yarn is 310 dtex or more, the strength of the woven fabric is at an excellent level as an airbag. Further, the total fineness is preferably 560 dtex or less, more preferably 470 dtex or less, in order to easily obtain a lightweight woven fabric.

The air permeability of the fabric used for the airbag of the present invention is preferably 0.5 ml/cm ² ·sec or less, more preferably 0.3 ml/cm ² ·sec or less, as measured by the Frazier method. is more preferred. By setting the above value, gas leakage from the surface of the base fabric is reduced when the airbag is deployed, and the size of the inflator can be reduced and it can be rapidly deployed. Further, the ventilation rate under a pressure difference of 20 kPa is preferably 0.9 L/cm ² ·min or less. With such a ventilation amount, the airbag can be deployed without losing the gas ejected from the inflator. Also, a suitable deployment speed can be obtained to quickly protect the occupants.

The single fiber fineness of the threads constituting the woven fabric may be the same or different. For example, it 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 folding the airbag. You can also make it lower. In addition, it is preferably 1.0 dtex or more because single fiber breakage is less likely to occur in the spinning process, the weaving process, and the like.

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

Various additives commonly used to improve spinnability, workability, durability, etc., such as heat stabilizers, antioxidants, light stabilizers, anti-aging agents, and lubricants are added to these fibers. , a smoothing agent, a pigment, a water repellent, an oil repellent, a masking agent such as titanium oxide, a gloss imparting agent, a flame retardant, a plasticizer, or the like.

The texture of the woven fabric may be plain weave, basket weave, lattice weave (ripstop weave), twill weave, ribbed weave, leno weave, satin weave, or a composite weave of these. If necessary, in addition to the two axes of warp and weft, a multi-axis design including an oblique angle of 60 degrees may be used. Among them, plain weave is preferable from the viewpoint of ensuring fineness of structure and uniformity of physical properties and performance.

The fabric used for the airbag of the present invention is preferably a non-coated fabric. 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 can be used for various occupant protection bags, for example, side bags for frontal collision protection of the driver's seat and front passenger seat, side bags for side collision protection, center bags, rear seat occupant protection (front collision, rear collision). ), rear collision protection headrest bags, leg and foot protection knee bags and foot bags, infant protection (child seat) mini bags, air belt bags, pedestrian protection for passenger cars, commercial vehicles, etc. 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>

In the airbag of the present invention constructed as described above, the stitching between the panels is performed by the stitching unit including at least one forward stitching and the backward stitching, so that the stitching can be performed without applying a reinforcing fabric or the like to the stitched portion. Suppression is possible. This point will be described in detail.

First, when the airbag deploys, a force acts as shown in FIG. 10 and 11 are diagrams showing a state in which the 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 warp extending direction. As a result, the adjacent wefts are separated from each other at the location where the suture is sewn, resulting in the opening of the stitches. Along with this, on the seam allowance side, the weft threads are displaced and the spacing between the weft threads becomes narrower.

On the other hand, in the present embodiment, the forward stitching and the backward stitching are combined to firmly sew the panels together. be able to.

In addition, since the forward stitching and the backward stitching are overlapped, the stitch pitch is narrowed. For example, in the example of FIG. 11A, the applied force F is received by 6 sutures, whereas in the example of FIG. 11B, the applied force F is received by 11 sutures. there is As a result, in the example of FIG. 11B as in the present embodiment, the force acting on each suture is dispersed, thereby suppressing the opening of the eyes.

Furthermore, in the present invention, since the forward stitching and the backward stitching 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 uniform, so that the same needle hole Z can be used for sewing. 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 achieve strong sewing. Note that FIG. 12A is described using the example of FIG. 4 . On the other hand, if the sewing is repeated a plurality of times, the positions of the needle holes may shift as shown in FIG. 12B. 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 the sewing is performed multiple times, the strength may be lowered. Therefore, according to the airbag of the present invention, strong stitching can be provided.

1 Panels 811-815, 821-825, 831-835, 841-845, 851-855, 861-876 Advance sutures 911-915, 921-925, 931-935, 941-945, 951-955, 961-965 , 971-973 Retracted Suture

Claims (3)

comprising at least two panels;
The peripheral edge of each panel is formed into a bag shape by a sewn part sewn with a suture thread,
At least a portion of the sutured portion includes at least one advancing suture sewn in the same direction as the suture advancing direction, and at least one retreating suture sewn in the opposite direction to the advancing direction and continuous with the advancing suture. A plurality of suturing units including suturing are arranged in the advancing direction,
the advancing suture and the retreating suture included in each of the suturing units are arranged so as to at least partially overlap;
each suturing unit includes one forward suture and one backward suture;
In the suturing units adjacent to each other in the advancing direction, the rear end of the advancing suture on the side opposite to the advancing direction is connected to the rear end of the retreating suture,
In the suturing part, in the suturing units adjacent to each other, the forward sutures and the reverse sutures are arranged in an odd number of 5 or more in total so as to overlap each other. 2. The airbag according to claim 1 , wherein in each of said stitching units, a ratio of said length of said backward stitching to said length of said forward stitching in said traveling direction is greater than 0.5 and equal to or less than 0.66. . comprising at least two panels;
The peripheral edge of each panel is formed into a bag shape by a sewn part sewn with a suture thread,
At least a portion of the sutured portion includes at least one advancing suture sewn in the same direction as the suture advancing direction, and at least one retreating suture sewn in the opposite direction to the advancing direction and continuous with the advancing suture. A plurality of suturing units including suturing are arranged in the advancing direction,
the advancing suture and the retreating suture included in each of the suturing units are arranged so as to at least partially overlap;
each suturing unit includes a plurality of forward sutures and a number of backward sutures that is one less than the number of forward sutures;
In the suturing unit adjacent to the advancing direction, the leading edge of the forward stitching in the advancing direction and the rear end of the advancing stitching opposite to the advancing direction are connected to each other.

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